DESIGN AND DEVELOPMENT OF PEDAL OPERATED MAIZE SHELLER

Transcription

1 DESIGN AND DEVELOPMENT OF PEDAL OPERATED MAIZE SHELLER BY VINAY [2014AE04M] Thesis submitted to the Chaudhary Charan Singh Haryana Agricultural University in partial fulfillment of the requirements for the degree of MASTER OF TECHNOLOGY (AGRICULTURAL ENGINEERING) IN PROCESSING AND FOOD ENGINEERING DEPARTMENT OF PROCESSING AND FOOD ENGINEERING COLLEGE OF AGRICULTURAL ENGINEERING AND TECHNOLOGY CCS HARYANA AGRICULTURAL UNIVERSITY HISAR (HARYANA) 2016

2 CERTIFICATE I This is to certify that this thesis entitled Design and development of pedal operated maize sheller submitted for the degree of Master of Technology (Agricultural Engineering), in the subject of Processing and Food Engineering to the Chaudhary Charan Singh Haryana Agricultural University, Hisar, is a bonafide research work carried out by Vinay under my supervision and that no part of this dissertation has been submitted for any other degree. The assistance and help received during the course of investigation have been fully acknowledged. Dr. V.K. Singh (Major Advisor) Department of Processing and Food Engineering College of Agricultural Engineering & Technology CCS Haryana Agricultural University Hisar (Haryana)

3 CERTIFICATE II This is to certify that this thesis entitled Design and development of pedal operated maize sheller submitted by Vinay to the Chaudhary Charan Singh Haryana Agricultural University, Hisar in partial fulfillment of the requirements for the degree of Master of Technology (Agricultural Engineering) in the subject of Processing and Food Engineering, has been approved by the Student s Advisory Committee after an oral examination on the same. MAJOR ADVISOR EXTERNAL EXAMINER HEAD OF THE DEPARTMENT DEAN, POST-GRADUATE STUDIES

4 Acknowledgements I take this pleasant opportunity to express my deepest sense of gratitude and heartfelt thanks to my major advisor, Dr. V.K. Singh, Asstt. Scientist, Department of Processing and Food Engineering, CCSHAU, Hisar for his supreme guidance, valuable suggestions, constructive criticism, sustained encouragement and ever willing help exhibited by him during the course of my investigation and writing up of this manuscript. I am immensely grateful to the members of my advisory committee Dr. M. K. Garg, Professor and Head, Department of Processing and Food Engineering, Dr. Rakesh Gehlot, Prof., CFST, Dr. Amarjit Kalra, Prof., Basic Engg. Section, COAE&T and Dr. K.S. Bangarwa, Prof. & Head, Deptt. of Forestry. I am indebted to them for their timely advice, valuable suggestions, generous co-operation and healthy discussion. I am greatly obliged to other teaching and non-teaching staff especially Sh. Mahadev, Sh. Shrigopal, Sh. Gopi and Sh. Ravi of Department of Processing and Food Engineering for their timely help in completion of this study. I extend my sincere thanks and gratitude to my friends Ajay and Vinod Kumar for their considerable contribution and their cheerful encouragement for successful completion of my M.Tech. degree programme. It gives me immense pleasure to acknowledge CCS Haryana Agricultural University, Hisar for providing me financial assistance in form of merit scholarship and offering me M.Tech. degree in Processing and Food Engineering. Last but not the least; Above all, I bow my head before almighty as without his blessings it was unfeasible to achieve the important land mark of my academic journey. Dated: VINAY Place: Hisar

5 CONTENTS Chapter No. Description Page No. 1. INTRODUCTION 1.1 General Background 1.2 Most relevant review of literature 1.3 Significance of study 1.4 Objectives REVIEW OF LITERATURE Maize Shelling Techniques Maize shelling machines Maize shelling theories Pedal operated mechanisms Past literature and researches Operational optimization using response surface methodology (RSM) MATERIALS AND METHOD Design and development of pedal operated maize shelling machine Performance parameters of pedal operated maize shelling machine Optimization of operational parameters using Response Surface Methodology (RSM) RESULTS Design and development of pedal operated maize sheller machine Performance evaluation of pedal operated maize sheller machine Optimization of operational parameters using Response Surface Methodology (RSM) DISCUSSION SUMMARY AND CONCLUSIONS BIBLIOGRAPHY APPENDIX i-iv I XV

6 List of Tables No. Title Page 3.1 Materials used for development of angle frame structure Materials used for development of shelling unit Materials used for development of transmission system Specification of plumber block Specification of transporting wheel Morphological characteristics of maize cob Independent variables with their range Dependent variables with their range Levels of coded variables Response surface experimental design in terms of coded 36 levels and actual levels 4.1 Dimensions of frame Dimensions of sheller Pedal side chain specifications Specification of chain connecting main and bearing shaft Specification of flywheel Calculated parameters of machine ANOVA for Response Surface Linear model 50 (Capacity of machine) 4.8 ANOVA for Response Surface Linear model 51 (Unshelled grain) 4.9 ANOVA for Response Surface Linear model 53 (Damaged grain) 4.10 ANOVA for Response Surface Linear model 54 (Shelling efficiency) 4.11 ANOVA for Response Surface Linear model (Cleaned outlet grain) 56

7 List of Figure No. Title Page 2.1 Antique Maize sheller "Bamba" motorized maize sheller The axial flow cage type sheller The rasp bar cylinder-concave sheller Axial flow twin rotor sheller Axial flow single rotor sheller The USDA sheller uses two endless rubber belts operating in 11 opposite directions to accomplish shelling 2.8 The compression-type sheller designed by Fox uses two 11 pneumatic tires operating at differential speeds 2.9 The functional components of the roller sheller designed by 12 Brass (1970) 2.10 Schematic diagram of the modified single rubber roller sheller 13 tested by Jaafari and Buchele (1976) 2.11 Schematic diagram of the modified double rubber roller 13 sheller tested by Jaafari and Bùchele (1976) 2.12 Schematic diagram of the spring-mounted rasp-bar sheller 13 (Peprah, 1972) 2.13 Schematic diagram of the dual sheller (Mahmoud, 1972) Sectional view of the Shelling mechanism patented by Wicks 14 (1858) 2.15 Sectional view of the shelling Mechanism patented by Parmele 15 (1861) 2.16 Sectional view of the shelling machine invented by Maizeell 15 (1869); (a) vertical section, (b) transverse section 2.17 Sectional view of the shelling machine patented by Sailer 16 (1911) 2.18 Sectional view of the conical shelling device patented by 16 Borcher (1943) 2.19 Sectional view of the shelling machine invented by Young (1974) 17

8 2.20 Maize dehusker-sheller Whole crop maize thresher Displacement of the loaded kernels may cause wedging of the 20 kernel rows and tension on adjacent attachments 2.23 The bending of kernel attachments resulting from cob 20 deformation is the basis for a shelling theory 3.1 Design flow chart for development of pedal operated maize 27 shelling machine 3.2 Pitch circle diameter of the chain sprocket Preliminary sketch of pedal operated maize shelling machine Cycle frame of pedal operated maize shelling machine Top view of machine Front view of the machine Transmission system of pedal operated maize shelling 40 machine 4.6 All view of the machine Experimental design and data for optimization operational Effect of shelling disc r.p.m and moisture content on capacity 50 of machine 4.9 Effect of shelling disc r.p.m and moisture content on quantity 52 of unshelled grain 4.10 Effect of shelling disc r.p.m and moisture content on damaged 53 grain 4.11 Effect of shelling disc r.p.m and moisture content on shelling 55 efficiency 4.12 Effect of shelling disc r.p.m and moisture content on cleaned 57 outlet grain 4.13 Optimize parameters of machine 58

9 List of Plates No. Title Page 3.1 Ground maize Balance (least count) Developed maize shelling machine 37

10 List of Abbreviations % Per cent cm kg g l m min t/h h s kj mt w.b d.b RSM r.p.m MC HQPM PVC Centimeter Kilogram Gram Litre Meter Minute Tonne per hour Hour Second Kilo Joule Million tonnes Wet Basis Dry Basis Response Surface Methodology Revolutions per minute Moisture content Hybrid quality protein maize Poly Vinyl Chloride

11 CHAPTER-I INTRODUCTION 1.1 General Background Maize (Zea mays) is one of the most common cereal grain grown in the world. It belongs to a grass family (Gramineae) and originated from Mexico and South America. The plant prefers light (sandy), medium (loamy), and heavy (clay) soils and requires well-drained soil. It cannot grow in the shade and also requires moist soils. The period between planting and harvesting for maize depend upon the variety, but in general the crop physiologically mature in 7 to 8 weeks after flowering, at that time the kernel contains 35 to 40% moisture and has the maximum content of dry matter. Maize shelling is difficult at moisture content above 25%, with this moisture content, grain stripping efficiency is very poor with high operational energy and causing mechanical damage to the seed. A more efficient shelling is achieved when the grain has been suitably dry to 13 to 14% moisture content. (Danilo, 1991) Maize, the American Indian word for maize, means literally that which sustains life. It is, after wheat and rice, the most important cereal grain, providing nutrients for humans and animals and serving as a basic raw material for the production of starch, oil, protein, alcoholic beverages, food sweeteners and more recently, fuel (FAO, 1992). Shelling is the removal or separation of maize grain from the cob and it is an operation that follows the harvest. It can be carried out in the field or on the farm by hand or machines. The grain is obtained by shelling, friction or by shaking the products. The difficulty of the operation depends on the varieties grown, the moisture content and the degree of maturity of the crop. Maize is shelled traditionally by hands. This is done in such a way that maize is rubbed against another until the grains are removed from the cob. Likewise the grain can be detached from the cob with the use of pestle and mortal. But this traditional method of shelling is highly tedious, inefficient and time consuming with low productivity (FAO, 2005). However, the modern way of shelling is by the use of mechanical means, which can be driven by prime mover or tractor. This prime mover can either be diesel/petrol engine or electric motor. The efficiency and throughput of this machine depending on the type of machine, the skill of workers and organization of the work, yield can vary from 100 to 5000 kg/h (FAO, 2005). The power requirement of such sheller is high and hence, the prime mover is very expensive. Akubuo (2002) observed that manual shelling of maize is time-consuming tedious operation and the few existing mechanized shellers on Nigerian farms are imported and out of reach of the rural peasant farmers that are characterized by small holding and low income. However, due to the initial cost and high operating cost of this machine a manually driven maize sheller can be 1

12 used to perform similar operation. The machine is hand powered and a blower is incorporated to separate chaff from the grains. The efficiency of this maize sheller depends on skill, age and some ergonomics parameter. In India, Maize is an important grain after the rice and wheat. According to advanced estimate India cultivated in 9.43 m ha mainly during Kharif season which covers 80% area and total production are 24.35mt of maize. Haryana state grows maize in an area of 9 m ha, with production of 27 mt (India Stat ). In our country with the increased in demand of poultry feed the demand for maize is also going up. It is the grain with the highest per day productivity. Some estimates indicate that India may have to produce 55 million tonnes of maize to meet its requirement for human consumption, poultry, piggery, pharma industry and fodder by The major steps involved in the processing of maize are harvesting, drying, de-husking, shelling, storing, and milling. For the rural farmers to maximize profit from their maize, appropriate technology that suites their needs must be used. 1.2 Most relevant review of literature Maize shelling a post-harvest operation is the removal of maize seeds from the cob. This operation can be carried out in the field or at the storage environment. Maize shelling therefore is an important step towards the processing of maize to its various finished products like flour. The different methods of maize shelling can be categorized based on various mechanization technology used. These includes: hand-tool-technology, animal technology, and engine power technology. Hand technology involves the use of hand tools in shelling, while as animals technology were used in threshing on the field by marching on the maize. Engine powered technology involves the use of mechanical assistance in threshing or shelling the maize. To facilitate speedy shelling of maize in order to reduce post-harvest deterioration, mechanical shellers are recommended; because hand shelling methods cannot support commercialized shelling. Shelling is a necessary process subsequent to harvesting because the maize kernels when harvested are firmly attached to the hard cob. Most of the low acreage maize growers encounter several difficulties in shelling as it involves relatively high labour expenditures and human energy. The energy consumption for only shelling of maize cob was per cent of total operational energy used in rainfed cultivation of maize crop in India (De, 2005). Singh (2010) reported that the farm women could dehusk 59 kg un-dehusked cobs/h. The farm women have to use their hands for nailing (1-2 times), tearing (2-3 times) and plaming (1-2 times) in order to dehusk a cob taking about 8-10 s. Shelling has previously been accomplished either by rubbing the maize cobs against one another by hand or by direct removal of kernels with low shelling rate. Another shelling technique for maize shelling is hand beating technique in which sacks stuffed with maize are beaten with a wooden flail 2

13 (Anonymous, 2000 and 2008; Bharati, 1998 and Nkakini, 2007). This method causes damage to the kernels. 1.3 Significance of study Maize is shelled traditionally by hands. This is done in such a way that maize is rubbed against another until the grains are removed from the cob. Likewise the grain can be detached from the cob with the use of pestle and mortal. But this traditional method of shelling is highly tedious, inefficient and time consuming with low productivity as worker can only shell a few kilogram per hour (FAO, 2005). The existing methods of maize de-husking in agriculture industry consist of breaking the grains by using large machinery for deseeding, both of which are not effective for a developing economy like India where farmers have little money for investment. The power operated maize sheller machine requires electrical energy for its working and its capital investment is also high compared to the conventional methods of shelling but in rural areas supply of electricity is not good at all times. Hence there was a need for an innovative idea or product that is feasible, safe, cost effective and productive for the Indian farmer. So in order to suit the prevailing condition and reduce the capital investment and operating costs, pedal operated maize sheller needs to be developed. 1.4 Objectives: Keeping in view the above facts, the present study has been has been undertaken by following objectives. It was proposed to design a pedal operated maize sheller with following objectives: 1. To design and develop pedal operated maize sheller. 2. To evaluate the performance of the maize sheller. 3

14 CHAPTER-II REVIEW OF LITERATURE This chapter includes summary of the past literature and researches which are relevant to the present study. The literature associated with various aspects of the present study is divided under the following subheads as 2.1 Maize shelling techniques 2.2 Maize shelling machines 2.3 Maize shelling theories 2.4 Pedal operated mechanisms 2.5 Past literature and researches 2.6 Operational optimization using response surface methodology (RSM) 2.1 Maize shelling techniques Depending on the influence of agronomic, economic and social factors, shelling is done in different ways: Shelling by hand, with simple tools Mechanical shelling with simple machines operated manually Mechanical shelling with motorized equipment Hand shelling The easiest traditional system for shelling maize is to press the thumbs on the grains in order to detach them from the ears. Another simple and common shelling method is to rub two ears of maize against each other. These methods however require a lot of labour. It is calculated that a worker can hand-shell only a few kilograms an hour. Shelling of maize, as well as of sunflowers, can be more efficiently accomplished by striking a bag full of ears or heads with a stick. Maize and sunflowers can also be shelled by rubbing the ears or heads on a rough surface. Small tools, often made by local artisans, are sometimes used to hand-shell maize. With these tools, a worker can shell 8 to 15 kg of maize an hour (Wanjala, 2014) Maize-shelling with Rotary Equipment Manual shellers, which are relatively common and sometimes made by local artisans, permit easier and faster shelling of ears of maize. These come in several models, some of them equipped to take a motor; they are generally driven by a handle or a pedal. Use of manual shellers generally requires only one worker. A good example is the Antique maize shellers. 4

15 The major setbacks with these shellers are that their shelling capacities are low and most of them require to be fixed on benches before operation. Also their method of operation is too cumbersome from the fact that the crank handle is directly connected to the shelling chamber and therefore the effect of friction is too vigorous during the shelling operational (Wanjala, 2014). Fig. 2.1 Antique Maize sheller Mechanized shelling or shelling with motorized equipment Now a days many small maize shellers, equipped with a rotating cylinder of the peg or bar type, are available on the market. Their output ranges between 500 and 2000 kg per hour, and they may be driven from a tractor power take off or have their own engine; power requirements vary between 5 and 15 hp according to the equipment involved. For instance the French Bourgoin "Bamba" model seems well-suited to rural areas in developing countries because of its simple design, easy handling and versatility (maize, millet sorghum, etc.) (Wanjala, 2014). Fig. 2.2 "Bamba" motorized maize sheller 5

16 2.2 Maize shelling machines The two types of shelling machines commonly used for shelling of Maize are: Conventional Maize shelling machines Nonconventional Maize shelling machines Conventional Maize Shelling Machines The two types of shelling mechanisms commonly used for field shelling of Maize are the axial flow cage sheller and the cylinder-concave sheller. Both shellers have a relatively high capacity and the capability of shelling snapped (unhusked) ear Maize. The popularity of the cylinder sheller has increased with the practice of field shelling high moisture Maize. The cage sheller (Figure 2.3) consists of a cylinder with lugs, helical flutes, or paddles which turns inside a cage. The cage has a perforated surface with holes large enough to let kernels fall though but retain the cobs. The ears are fed into an opening at one end of the cage. The helical flutes feed the ears though the cage and at the same time shell them by a rolling and crushing action against the cage surface and each other. An adjustable cob gate serves to retain the ears the cage long enough to be completely shelled. The cages are usually from 27.9 to 38.1 cm (11 to 15 inches) in diameter and the cylinders have rotational speeds of 650 to 790 r.p.m. The capacity of these shellers is in the order of 4 to 5 metric tons per hour (150 to 200 bushels per hour). This shelling unit is generally used as a shelling attachment mounted on a two-row Maize picker in place of the husking bed, although self-propelled Maize harvesters using this type of sheller are available. Fig. 2.3 The axial flow cage type sheller 6

17 Fig. 2.4 The rasp bar cylinder-concave sheller Ability to shell high-moisture Maize is important when field shelling. Burrough and Harbage (1953) showed cage sheller losses of 5 to 10% when kernel moisture was 29.6% and cob moisture was 56.5%, wet base. Part of the loss was due to unshelled Maize remaining on crushed cob sections, and part to difficulty in separating the damp kernels from the cobs. The percentage of kernels left on the cobs and the percentage of kernels damaged by shelling were almost directly proportional to the moisture content of the kernels. The second basic shelling mechanism, commonly used in combines, consists of a cylinder and a concave (Figure 2.4). The Maize is shelled by the impact of bars on the periphery of the cylinder as the Maize is fed between the cylinder and the concave bars. The most common type of cylinder bar used is the rasp-bar. These bars were shown to cause less damage than an angle-bar type cylinder. (Pickard, 1955) observed that cylinders are commonly 55.9 cm (22 inches) in diameter and range from 61 to 152 cm (24 to 60 inches) in length, depending on the size of the combine. For Maize shelling, they turn at speeds of 400 to 700 r.p.m. The concave assembly nearly conforms to the periphery of the cylinder. It forces the Maize to be in contact with the cylinder though about 90 degrees of cylinder rotation. The concave bars are channel, rectangular, or half round in shape and are oriented parallel to the cylinder axis. The severity of the shelling action is controlled by the cylinder speed and the cylinder to concave clearance. Clearance at the front of the concave is approximately 3 cm. This allows ears to easily enter the shelling crescent between the cylinder and concave assembly. The cylinderconcave clearance tapers to the rear and is about 1.5 cm at the rear of the concave. The severity of the shelling action determines the amount of unshelled Maize remaining on the cob and the level of kernel damage. Cylinder adjustments are a compromise between high speeds for kernel removal and low speeds for reduced kernel damage. Reducing the concave clearance also increased the thoroughness of shelling and the level of kernel damage. 7

18 Kernel moisture content is another factor that has a great influence on kernel damage (Hopkins and Pickard, 1953; Barkstrom, 1955; Goss et al., 1955; Pickard, 1955; Fox, 1959; Brass, 1970; Hall and Johnson, 1970; Mahmoud, 1972). These researchers reported that mechanical kernel damage increased rapidly with increasing moisture content over approximately 20%, However, Maize shelled at moisture contents considerably below 2056 moisture also suffered high levels of damage. Minimum kernel damage was generally found to occur at kernel moisture contents of 18 to 22%. In a field survey conducted on 84 Maize combines in north central Iowa (Ayres et al. 1972), the total kernel damage averaged 34.4% and ranged from 16.4 to 79.4% (as determined by visual inspection). Maize harvested in this survey ranged from 12 to 23.9% moisture content. Combine performance, based on low field losses and total damage, was reported to be best for Maize between 18 and 22% moisture. A series of tests was conducted by Morrison (1955) on kernel damage comparisons between the combine cylinder and the cage-type sheller. For kernel moisture contents below 15%, the combine cylinder resulted in greater kernel damage than the cage-type sheller. For this reason the cage-type sheller is used for shelling seed Maize after the Maize has been dried on the ear. In the moisture range of 15 to 20%, there was no appreciable difference in kernel damage with the two machines. Above approximately 20% kernel moisture, the combine cylinder resulted in much less kernel damage than the cage-type sheller. (Skromme, 1977; DePauw et al. 1977) developed two new combines. These combines utilize twin or single longitudinal rotors to replace the conventional cylinder and straw walkers for shelling and separating the grain from the other plant parts. The twin rotor thresher shown in Figure 2.5 is used in axial flow combines for shelling and separating grain, including Maize. This thresher consists of two 43.2 cm (17 inches) diameter rotors operating inside dual shelling and separating grates. These two rotors, which are cm (88 inches) long, are positioned side by side axially along the combine. Spinning in opposite directions, the rotors move the crop in a helical motion against shelling grates enclosing the rotors. The speed of the rotors is adjustable from 5 80 to 1325 r.p.m depending on the requirement of the crop being harvested. The crop is threshed by a flailing (impact) action and separated from the straw by the centrifugal force exerted by the spinning rotors. This new shelling machine is claimed to have smooth performance, and to produce less grain damage, but Skromme gave no specific details about the amount of damage and how it was affected by moisture content when shelling Maize, which is the interest of this study. A single thresher rotor (Figure 2.6) was also used for shelling Maize in axial flow combines (DePauw et al. 1977).The shelling rotor, which is 76.2 cm) 30 inches) in diameter and cm (108 inches) long, is a one-piece cylindrical structure with impellers at the front and rasp bars around the forward part of its circumference. The rasp bar section of the axial rotor is immediately behind the impeller blades and has helically and axially mounted rasp-bar sections. The helically mounted rasp 8

19 bars continue the helical crop flow pattern started by the impeller blades. The crop material flows around the rotor housing several times before reaching the separator section of the housing. Rotor speed can be varied from 280 to 1250 r.p.m to meet shelling requirements for numerous crops. The rotor cage consists of a funnel-shaped front opening with spiral vanes to control the crop flow to the impellers. Additional vanes along the side of the shelling chamber control the movement of the material though the machine. The bottom of the cage is made up of a set of three adjustable bar and wire concaves toward the front and a set of three stationary separating grates to the rear. The grain is threshed by a combination of impact, rubbing and centrifugal action as the crop passes repeatedly across the concaves and grates. The axial flow single rotor thresher was claimed to have less grain damage compared with the conventional combine cylinder. For Maize specifically, the kernel crackage was stated to be two-thirds as much as that of the conventional combine cylinder. No information was reported concerning the effect of moisture content on the level of grain damage. Fig. 2.5 Axial flow twin rotor sheller Fig. 2.6 Axial flow single rotor sheller 9

20 2.2.2 Non conventional Maize Shelling Machines Maize shelled by the conventional combine cylinder suffers a high level of kernel damage. Several com shelling machines have been developed by different research workers in an attempt to shell Maize with a relatively low damage compared to that caused by the high impact action of the combine cylinder. Although the new experimental machines succeeded in reducing the level of kernel damage, they lacked other functional requirements such as high shelling efficiency, high capacity, and durability. An experimental sheller that handles Maize gently during the shelling operational was designed by USDÀ agricultural engineers (1967), This shelling device (Figure 2.7) consisted of two endless rubber belts rotating in opposite directions at different speeds. The ears of Maize were rolled though the unit and were shelled with an intensifying squeezing action provided by an adjustable pneumatic spring located at the discharge end. In laboratory tests with this device, Maize at 15% moisture content was shelled with no apparent damage to the kernels. However, the low durability of the belts, low capacity of the sheller, and the decreased in shelling efficiency at high moisture are major problems of this shelling system. The principle of rolling and squeezing was used in another experimental sheller designed by Fox (1969). This machine consisted of two smooth-surfaced tires mounted with their axes parallel as shown in Figure 2.8. The two rollers rotate in the same direction but at different speeds. A feeder plate shaped to the contour of the tire was used to orient and feed the ears between the rollers. The hypothesis was that the combination of compression, low impact and centrifugal force induced by the sheller reduced the strength of the kernel attachment to the cob. The wedging action of the kernels and the centrifugal force cause failure of the weakened attachment and the kernels are shelled as the ear is rotated between the rollers. Fox ran comparative damage studies using the rubber roller sheller and a combine cylinder. Kernel damage of Maize shelled by the rubber roller sheller ranged from 6% damage at 22% moisture content to 9% damage at 30% moisture content, while Maize shelled in the combine cylinder ranged from 15% to 30% damage for 22% and 30% moisture content, respectively. However, the rubber roller sheller was reported to have feeding problems, and its shelling of unhusked ears was unsatisfactory. Fox did not report the shelling capacity of the rubber roller sheller and how it compared to the capacity of a conventional combine cylinder. Another roller sheller was designed and tested in the laboratory by Brass (1970). This sheller used a combination of compression and ear rotation for Maize shelling. The basic components of the machine (Figure 2.9) are a smooth tread pneumatic roller in combination with a concave and a second pneumatic orientation roller. Both the primary and orientation rollers rotate in the same direction. The opposing surface motion of the two rollers causes the ear of Maize to attain an orientation parallel to the roller axis while simultaneously subjecting each ear to several cycles of compression loading. After passing the orientation roller the ear moves onto the concave, continuing the rolling motion that it has attained. 10

21 Shelling is induced in the concave area by the combination of rolling action and cyclic compressive loading imparted to the rows of kernels as the ear passes over the concave bars. Both around steel bar concave and a rubber bar concave were tested in the new machine. In damage comparison tests against a conventional combine cylinder, the rubber roller sheller inflicted a lower level of total damage upon the grain at all moisture contents than did the combine cylinder, although the difference was less at the highest grain moisture content tested. Minimum kernel damage of 18% occurred at approximately 19% kernel moisture, compared to 33% damage for the combine cylinder at the same moisture content. The rubber covered concave bars reduced damage more than the steel bars at the lower moisture contents tested, but caused a greater amount of damage than the steel bars at the highest moisture content. Besides excessive wear, the rubber roller sheller also had feeding problems and low shelling efficiency at high moisture contents. Fig. 2.7 The USDA sheller uses two endless rubber belts operating in opposite directions to accomplish shelling Fig. 2.8 The compression-type sheller designed by Fox uses two pneumatic tires operating at differential speeds 11

22 Fig. 2.9 The functional components of the roller sheller designed by Brass (1970) Jaafari and Buchele (1976) tested modified versions of the two roller shellers designed by Fox and Brass. Their objectives were to eliminate the feeding problems and improve the shelling performance of the rubber roller shellers. The modified shellers are illustrated in Figures 2.11 and 2.12; Maize shelled by the modified single and double roller shellers was also reported to have a lower damage level compared to Maize shelled in a conventional combine cylinder. Peprah (1972) hypothesized that spring-mounting the rasp bars of conventional rasp-bar cylinders would reduce damage to kernels during shelling. Laboratory tests were performed in which Maize was shelled with a modified combine cylinder with spring mounted rasp bars (Figure 2.12). Shelling efficiency and percent kernel damage for various spring constants were determined. The test results revealed that the spring-mounted rasp-bar sheller had objectionably low shelling efficiency at low speeds. However, shelling efficiency increased with increasing speed, especially when softer springs were used. Comparative damage studies showed that the spring-mounted rasp-bar sheller had a slightly lower percent damage than the conventional combine cylinder. The percent damage decreased with a decreased in the spring constant and increased with speed. Mahmoud (1972) studied the damage distribution along the shelling crescent of a rasp-bar combine cylinder. In laboratory tests, he found that the damage increased as the grain traveled down the concave. The increased in damage along the concave was believed to be caused by the repetitive impacts on the ear and shelled kernels by the cylinder rasp-bar. Since shelling becomes easier after some kernels have been detached, he suggested that the shelling mechanism could be modified to eliminate the unnecessary impacts on the ear. A dual sheller was proposed by Mahmoud as illustrated in Figure This sheller consisted of a conventional combine cylinder, a shelling grate and a belt sheller. The cylinder provides the high impact forces necessary to initiate the shelling, and the rubbing action of the belt completes the shelling of the partially shelled ears. 12

23 Fig Schematic diagram of the modified single rubber roller sheller tested by Jaafari and Buchele (1976) Fig Schematic diagram of the modified double rubber roller sheller tested by Jaafari and Buchele (1976) Fig Schematic diagram of the spring-mounted rasp-bar sheller (Peprah, 1972) The proposed sheller combines the desired impact forces of the cylinder to initiate shelling and the proven damage reduction achieved by the belt sheller. However, Mahmoud did not build a model to verify his hypothesis. Selected Maize Shelling Machines Covered by U.S. Patents Wicks (1858) patented a mechanism in which he employed two spirally toothed 13

24 cylinders, in conjunction with a toothed wheel for shelling Maize as shown in Figure The two cylinders revolve and feed the ears of Maize downwards while they are being shelled by the shelling wheel. Another maize sheller was invented by Parmele (1861). His sheller (Figure 2.15) consisted of two ribbed cylinders placed one over the other in the same axial plane, and a vertical corrugated concave plate (C in Figure 2.15). The lower cylinder was rotated four times faster than the upper cylinder. The upper ribbed cylinder rotates the ear with a moderate movement, while the lower ribbed cylinder effectively shells the Maize from the cob by its comparatively rapid movement. The shelled Maize passes though the screen F and the cob is conveyed around and forced out though the flap I. À Maize shelling mechanism (Figure 2.16) which consisted of two cylinders rotating in the same direction but at different speeds was invented by Maizeell (1869). The two cylinders were located vertically parallel to and adjacent to each other. One cylinder, E, is corrugated its entire length while the other cylinder, D, is covered with spiral hooked teeth. A spring holds the ears of Maize against both cylinders. The one turning slower allows the ears to turn, while the faster cylinder strips off the Maize, and also draws the ears down though the machine with its spiral teeth. Fig Schematic diagram of the dual sheller (Mahmoud, 1972) Fig Sectional view of the Shelling mechanism patented by Wicks (1858) 14

25 Fig.2.15 Sectional view of the shelling mechanism patented by Parmele (1861) Fig Sectional view of the shelling machine invented by Maizeell (1869); (a) vertical section,(b) transverse section Sailer (1911) patented a Maize sheller (Figure 2.17) which consists of two horizontal parallel cylinders, one of which is provided with thead-like teeth. The other is provided with longitudinal spirally disposed rib-like teeth. Acting with these cylinders is a toothed plate which is yieldingly supported in an inclined position above the cylinders. As the ear is fed between the cylinders, it is rotated as well as being carried forward. The teeth on the cylinders and on the plate spread and loosen the kernels from the cobs. A Maize sheller particularly intended to be used for shelling seed Maize was made by Borchers (1943). The shelling device (Figure 2.18) consisted of a conical member rotating inside a hollow cone. The rotating cone has a plurality of nonmetallic pliable projections on its outer face, and the hollow cone has similar projections on its inner surface. These flexible projections elastically engage the kernels of Maize while on the cob and rub they off the cob without substantial damage to the kernels. The inner cone is adjustable endwise to accommodate variable sized ears of Maize. Young (1974) patented a Maize sheller (Figure 2.19) which consists of a cone-shaped drum rotating inside a truncated 15

26 cone-shaped housing. Both the rotating drum and the stationary housing have resilient the ads protruding spirally around their surfaces. The ears are fed to the open upper end of the housing and as they pass between the inside surface of the housing and the exterior surface of the rotating drum, the resilient the ads apply a compressive force to the ears which dislodge the kernels from the cobs. The kernels pass though perforated portions of the housing while the cobs are discharged from the lower end of the housing. Fig Sectional view of the shelling machine patented by Sailer (1911) Fig Sectional view of the conical shelling device patented by Borcher (1943) 16

27 Fig Sectional view of the shelling machine invented by Young (1974) Maize dehusker-sheller The department of Farm Power & Machinery, PAU Ludhiana developed two types of Maize dehusker cum threshers namely spike tooth type (modified version of wheat thresher) and axial flow type (modified version of sunflower thresher) for threshing the maize along with the husk. It is used for dehusking and shelling of maize cobs simultaneously. It is operated by a PTO of 26.1 kw tractors. In the spike tooth type sheller, pegs are staggered at varying heights for better shelling efficiency. The spikes are placed in 6 rows with 6 pikes in each row. The sieves have 1.25 cm diameter opening to separate the shelled maize from husk. Fig Maize dehusker-sheller 17

28 In axial flow type threshers, pegs are provided on the cylinder and louvers were provided on the upper periphery of the drum to convey the crop to the outlet. Working capacity of sheller is q/h. Weight of the machine is about kg. Shelling efficiency is about 100% in both the cases and broken grains are maximum up to 2.0%. Dehusking-cum-shelling saves lot of labour in comparison to traditional system. Performance results of the machine are given below. ( Whole crop maize thresher A whole crop maize thresher developed at MPUAT Udaipur with the objectives to do the shelling of maize cob and simultaneously stalk is converted to chaff. A tractor operated multi crop thresher was also modified with arrangement so of spikes on threshing cylinder and concave made of 8 mm square bar with 19 mm spacing. The output of grain was observed as 710 kg/h with chaff size of 16 to 63 mm. This chaff was fed to the animals and 85% material was consumed in comparison to the whole stalk. The significant saving in labour was found for detachment of cobs and transportation of crop from field to home. The threshing efficiency was 99% and cleaning efficiency 96.4%. Fig. 2.21Whole crop maize thresher Tractor-drawn combines with suitable adjustment can be used for de-husking and shelling of maize in stationary operation. The following adjustments can be made in the combine before using for maize shelling: (i) The drive to cutter bar should be disconnected and reel removed for easy feeding of maize ears. (ii) Rasp bar cylinder used for wheat threshing should be used for maize threshing. The speed of the cylinder may be kept between rpm as compared to 900 rpm for wheat. 18

29 (iii) Cylinder-concave clearance should be around 25 mm for maize threshing. (iv) The sieve in the cleaning shoe should be replaced by large size hole (approximately 12.5 mm). (v) If the combine does not have a grain tank, grain should be collected directly from the chaffer to avoid grain damage. However, if the grain tank is provided no such change is necessary. (vi) There should be at least two canvas screens on the straw rack/walkers. One screen is normally provided at one-third distance in the first portion. The second screen should be provided at one-third distance from the rear. This is necessary to avoid grain losses. The combine, if modified as above, can be used for de-husking and shelling of maize cobs satisfactorily at cylinder speed of 575 rpm and cylinder-concave clearance of 20 mm. The capacity of machine ranges between t/h at a feed rate of t/h. Cylinder and shoe (including rack) losses are 1.5% each and grain crackage about 2%. ( 2.3 Maize Shelling Theories Several theories have been developed for the purpose of explaining the shelling operational. In formulating a theory descriptive of the actual shelling operational, a dynamic analysis of the problem should be implied. However, because of the complicated structure of the ear and the heterogeneous nature of the material, most researchers have resorted to a quasistatic approach using an idealized model. Some experimental work has also been done in an attempt to extend these theories into the dynamic range by using simple impact loading tests. Two additional shelling theories have been proposed by Halyk et al. (1969) and Johnson et al, (1969). Their respective theories are derived from consideration of Figures 2.20 and In the Halyk et al., theory the kernels and the cob are assumed to be composed of a rigid material, such that their deformation was insignificant when compared to the deformation of the kernel attachment or pedicel. As the load P is applied, the first segment of kernel depression takes up the clearance space between the rows of kernels around the circumference of the ear. Additional loading and kernel depression cause tensile and bending forces on the pedicels of adjacent kernels due to the wedging action of the kernels in the available circumferential space. Shelling occurs by failure of the pedicel of a kernel adjacent to the depressed kernel because this element is subjected to the greatest strain. In order to assess the validity of the theory, Halyk et al. (1969) conducted quasi-static and low velocity impact shelling experiments in the laboratory. They observed that shelling occurred in the row 19

30 adjacent to the loaded kernel as predicted by the theory. However, the theory was found to apply only to Maize kernels having average moisture content below 15.3% wet basis. Fig Displacement of the loaded kernels may cause wedging of the kernel rows and tension on adjacent attachments (Halyk et al., 1969) Fig The bending of kernel attachments resulting from cob deformation is the basis for a shelling theory by Johnson et al. (1969) 2.4 Pedal operated mechanisms The pedal powered air compressor set up, has a simple mechanism operate with the chain and sprocket arrangement. The chain is place on the teeth of the wheel and pinion. Pedal and connecting rod are interconnected to each other with bolts. It is arguable that the most important development, technically and socially, in the nineteenth century was the bicycle. Pre bicycle technology was heavy and inefficienttypically the steam locomotive-but post-bicycle technology became lightweight and efficient, both structurally and mechanically. Witness the light weight tubular steel frame, wire spooked 20

31 wheel, bush roller chain, ball bearings, and pneumatic tire. All these, developed specifically for the bicycle, led to a triumph of ergonomics matching the machine to the human beings. In energy terms the reason the bicycle is so efficient is that it uses the most powerful muscles in the body-the thigh muscles-in the right motion, a circular pedaling motion, at the right speed, revolutions per minute, and then transmits the power efficiently by means of a crank system, sprocket-and-chain mechanism and ball bearings. This technology is most commonly used for transportation and has been used to propel bicycles for over a hundred years. Kajogbola et al. (2010) designed and developed a pedal soap mixer. The machine consists of a chain drive and gear amplification mechanisms that turns impeller blades in a large stainless steel container, where soap ingredients are stirred and blended. The machine is economically viable, can be used by unskilled workers, save time otherwise spent in traditional mixing and can be adopted for human-powered operational units which could have intermittent operation without affecting the end-product. Bahaley et al. (2012) analyzed the performance of pedal powered multipurpose machine. A human powered multipurpose machine was developed which lifts water to a height 10 meter and generates 14 Volt, 4 ampere of electricity in most effective way. Power required for pedaling was well below the capacity of an average healthy human being. The system was also found useful for the work out purpose because pedaling will act as a health exercise and also doing a useful work. Chand et al. (2013) developed Pedal Operated Integrated Potato Peeler and Slicer. For the processing of potatoes, removal of the peel is an important unit operation. The main parts of the integrated machine were peeling drum, water spraying unit, slicing unit, a piston to transfer the peeled potato from peeler to slicer and a power transmission system. The peeling drum, with protrusion on the inside surface, rotated and detached the peel from the potatoes by abrasion. The water spraying unit washed the potatoes and, simultaneously, the peel was removed from the drum though the peripheral clearance of the drum along with the flow of water. The miter gears, transmission shafts and chain drives were significant parts of the machine. The machine worked at 45 r.p.m with a 65 kg/h capacity. Tambari (2015) designed and fabricated of a pedal powered hacksaw cutting machine. The aim of this work is to develop a modernized and less stressful operation for cutting wood, metals and plastic materials. It is very useful for cutting PVC materials (pipes) and can be used widely in lather and in furniture making industries. This work can also serve as an exercising machine for fitness while cutting; it uses the principle of a slider crank mechanism which converts the rotary motion of the flywheel to the reciprocating motion of the hacksaw during pedaling. The machine was tested and continued to be very efficient with an ideal mechanical Advantage of 0.5 (less than 1), velocity ratio of 0.65 (less than 1), a 21

32 power output of 5.72 KW and an efficiency of 76.9%, which makes it very adequate and capable for cutting. 2.5 Past literature and researches Sharma (2007) studied to developed such a machine and suggest the farmers to adopt suitable values of crop and machine operational parameters for the optimum threshing. The studies were carried out in three different phases. In the first phase, physical properties of maize kernel and maize cob that have bearing on dehusking and shelling performance of maize thresher were determined. These include length, breadth, thickness, bulk density, sphericity and terminal velocity for maize kernel; and cob size and grain-to-non grain ratio for maize cob. In addition, an effort was also made to determine the force required to detach husk and a single kernel from maize cobs using a pendulum device which was specially developed for this purpose. Results indicated that the size of the maize kernel ranged from mm and grain-to-non grain ratio from The force required to detach husk and a single kernel from maize cob ranged from N and N respectively. Hassan et al. (2009) studied that many farmers grow maize but could not afford the cost of acquiring some of the imported shelling machines because of their cost. Such people resort to manual means of shelling which results into low efficiency, high level of wastage and exerting of much labor. This machine was constructed to shell maize and separate the cob from the grains. It was constructed from locally available materials and its cost is very low and affordable. Its shelling efficiency is 99.2% and breakage is very insignificant, as well as losses. Tiwari et al. (2010) explained operating speed of rotary maize sheller was optimized for its operation at higher operating speeds in pedaling mode, by conducting a simulation study for three sizes of maize cobs at seven operating speeds. The shelling capacity and shelling efficiency of maize sheller for all categories of maize cobs increased curvilinearly with increased in operating speed up to about 70 r.p.m. The shelling capacity at a particular operating speed decreased with increased in the maximum diameter of cobs. Operating torque of rotary maize sheller for a given size of maize cobs decreased with increased in operating speed. On the other hand, the torque decreased with decreased in maximum diameter of maize cobs at a given operating speed. It was concluded that the operating speed of maize sheller should be 70 to 80 r.p.m for higher shelling capacity, shelling efficiency and lower operating torque. Nwakaire et al. (2011) designed constructed and evaluated a low cost maize sheller for rural farmers in Nigeria. The methods used involved the collection of farmer s opinion on their sheller needs, selecting appropriate materials, and utilization of theories of failure that enable the determination of allowable shear stress on the bearing supports. The communication methods used were interactive sessions with farmers especially the women 22

33 and children determine their shelling problems. Comparison was made between the human performance index for shelling and the machine performance index. The human mechanical efficiency, though-put capacity and grain handing capacity are 45%, 26.67kg/h and 21.1kg/h at a biomaterial test weight of 20kgwith actual shelled weight of 15.8kg at a shelling time 45 minutes. For machine indices, though-put capacity and the grain handing capacity of the sheller are 86%, kg/h and kg/h respectively. The price difference shows a drastic eduction in the purchase price of maize thresher by N 32, (216.67), which represents 56.52% price reduction. Singh (2013) examined that hand operated maize dehusker-sheller was ergonomically evaluated with tenfarm women to assess the physiological workload and its performance in standing and sitting postures. Two workers are required during its operation, i.e., one for hand cranking and another for feeding the cob. One by one cob (without removing its outer layer/sheath) was fed in hopper at an interval of about 4 s. Farm women operated the equipment at their rhythmic speed in both postures. The average heart rate of subject was 144 and 142 beats per min in standing and sitting postures, respectively. The overall discomfort rating (ODR) and Body Parts Discomfort Score (BPDS) clearly indicated that the standing posture could be better option for operation of this equipment. This was found to reduce the physiological cost by 38.95% and 21.62% in dehusking & shelling the maize cob with hand, and dehusking by hand & shelling by octagonal maize sheller respectively. Oriaku et al. (2014) concluded agricultural products like maize, soya bean, millet and rice, when processed into quality forms not only prolongs the useful life of these products, but increased the net profit farmers make from mechanization technologies of such products. One of the most important processing operations done to bring out the quality of maize is de-cobbing or shelling of maize. Consequently, a de-cobbing and separation machine was designed, fabricated and its performance evaluated. Maize at moisture content of 15.14% (dry basis) sourced locally was used in the experiment and the data collected were analyzed. Results showed that for a total 20kg of sample tested, the average feed and shelling time were 2.37 and 2.95 minutes respectively. The average feed and shelling rates were 2.06 and 1.65 kg/min with an average shelling efficiency of %. The average separation efficiency was %. These results indicate that shelling and separation can be performed out satisfactorily with the designed machine and it can be used to operational about 1 tonne of maize per nine-hour shift. Shelare et al. (2015) studied that there are many maize shelling techniques in India which are used in our life. The main problems with these machines are that they are not affordable to farmers who are having acreage farms and which they do not require these big shelling machines. Many farmers in India are not affordable to use these machines because of their cost. So these farmers resort hand operated tools which gives low output, more damages of kernel threshed from cob, which is monotonous work. Since inventions of maize shelling by machines reduced the hectic work for farmers but these machines never provided the cost 23

34 saving, accident precautions. These machines are automatic operated, fuel operated. So as man machine system can be established these machine provides simple mechanical design. This literature report is review on human powered machine, the survey proved to system which shows cost effective and functional viable. Karikatti et al. (2015) found that dehusking and shelling are important post-harvest activities in maize crop, predominantly done by women. These activities involve a lot of drudgery as these are done manually. The maize shelling with the tool makes women's lives difficult and yields very low level of output. Moreover, dehusking as a separate activity precedes shelling that brings additional burden on farmers. They may employ labourers or use machines. But in villages, there is a shortage of labourers, and their wages are also pretty high. The farmers or field owners find it difficult to afford the machines. In order to make it affordable and more convenient to shell the maize, and as a part of our academic project, we have developed a Crank Operated Maize Sheller using ergonomic and mechanical considerations for dehusking and shelling. It consists of feeder from where the maize is inserted. The crank is connected to the blade. When the crank is turned, the blade rotates and shells the maize. The machine is operated by 1 person and requires feeding of cobs one by one. 2.6 Optimization of operational parameters of machine using response surface methodology (RSM) Response Surface Methodology is a statistical tool which explores the relationships between several explanatory variables and one or more response variables. The method was introduced by Box and Wilson in The main idea of RSM is to use a sequence of designed experiments to obtain an optimal response. RSM is a very useful tool in operational optimization (Cochan and Cox, 1957). RSM comprises a group of statistical techniques for empirical model building and model exploitation. In this, the tests are performed by using different combinations of experiments according to a predetermined design and an appropriate data are fitted to the experimental data by the method of least squares. Three dimensional plots provide a very useful aid for checking the adequacy of the model, for examining the response surface and location of the optimum conditions. The advantages of design of experiments as reported by Adler et al. (1975) and Johnston (1964) are as follows. 1) Numbers of trials are reduced. 2) Optimum values of parameters can be determined. 3) Assessment of experimental error can be made. 4) Qualitative estimation of parameters can be made. 5) Inference regarding the effect of parameters on the characteristics of the operational can be made. 24

35 Singh et al. (2008) designed and developed a pedal-operated paddy thresher. The machine performance was evaluated for optimal design parameters, viz., wire loop spacing 39.1 mm, wire loop tip height 60.6 mm and shelling drum speed m min 1. The corresponding shelling capacity and efficiency were 64.6 kg h 1 against predicted 66.8 kg h 1 and 96.4% against predicted 98.3%, respectively. Comparative performance tests between the newly developed thresher and the old pedal thresher were conducted to test the effects optimization. Paddy thresher performed better compared to the existing pedal thresher. The weight and cost of the paddy thresher were lower than the existing pedal thresher. The power source for operating the thresher was either one person or a kw electric motor. Ojomo et al. (2012) investigated that the optimum condition of operating the performance parameters of a locally developed maize shelling machine. A response surface methodology with three levels (-1, 0, +1) was used as the experimental design. Independent variables to be optimized are shelling efficiency, Cleaned outlet grain, heavy unwanted materials and light unwanted materials. The experiment was performed using a maize shelling machine previously developed at the Agricultural Engineering department of Rufus Giwa Polytechnic, Owo, Ondo State, Nigeria. Seventeen treatments were randomly experimented following the Bob-Behnken design and the experimental data on Machine Speed, ConcaveCylinder Clearance and the Moisture Content of the Machine parameters treated as response variables were fitted into a quadratics polynomial model. The result shows the optimum conditions at which maize could be shelled using a locally fabricated maize shelling machine. 25

36 CHAPTER-III MATERIALS AND METHODS This section includes the materials used and the methods and procedures that were adopted for conducting investigation. The experiments were conducted with the following objectives: 1. Design and development of pedal operated maize shelling machine 2. Performance parameters of pedal operated maize shelling machine 3. Optimization of operational parameters using Response Surface Methodology (RSM) The detailed description of materials and methods is as follows: 3.1 Design, development and performance evaluation of pedal operated maize shelling machine Idea generation India is the third largest producer of maize and due to the increased in demands of its processed form (preserve) both in national and international markets, shelling is considered as a major economic activity for the individuals associated with it. In developing countries like India there is always a problem of availability of resources and power especially in the rural areas. The supply of electricity is not uniform and fossil fuels are not always an option when farmer wants to keep the operating costs of a operational low in order to increase the profits. Also, rural women are among the least privileged, not only do women perform agricultural duties and care for livestock alongside men, but women are also responsible for many domestic chores. Usually, new technology improves people s efficiency, but women benefit less from new technology for several reasons. There are existing solutions and machines were developed in the past that runs on manual power but the capacity and quality of shelling was poor. Also the maize need to be graded so that they can fit in these machines and the effort required was more leading to repetitive strain injuries during a longer span of time due to the postural discomfort. So, the idea was to design and develop a gender equal machine which can eliminate the need of size grading and can run on manual energy with a little effort and more capacity. The flow chart that was followed for designing and development operational of the machine is as follows: 26

37 Fig.3.1 Design flow chart for development of pedal operated maize shelling machine Sketch and preliminary design A preliminary conceptual design was prepared using CorelDraw thereby forming the basis of the design and development operational Selection of materials Various materials that were used in the fabrication of the machine were listed Frame structure This formed the main skeleton of the machine. It was made strong enough to resist the maximum magnitudes of compressive, tensile and impact forces and simultaneously support the other parts of the machine fixed on it. Table 3.1 Materials used for development of angle frame structure Sr. No. Name of part Materials used 1. Frame structure Different Mild steel used to formed frame structure (Solids rods and Hollow pipes) Shelling Unit The shelling unit was fixed on the left side of the machine. It consisted of cast iron sheller for shelling, an adjustable spring was joined to the shelling unit to adjust the diameter of the shelling unit according to the size and shape of the maize, bearing and bearing rods for transmission of power and movement of shelling assembly. The side of the shelling assembly was covered for safety purposes. The list of various materials that were used is as follows: 27

38 Table 3.2 Materials used for development of shelling unit Sr. No. Name of part Materials used 1. Sheller Mild steel 2. Shelling disc plate Mild steel 3. Frame Mild steel 4. Adjustable spring Hardened steel Transmission system It includes the various components which were employed to transmit the power from the lower back and leg muscles of the worker finally to the shelling unit with the help of shafts, chains and sprockets and plumber block. Table 3.3 Materials used for development of transmission system Sr. No. Name of part Materials used 1. Chains and sprockets Stainless steel sprockets and cast iron chains 2. Shafts Mild steel 3. Flywheel Mild steel 4. Plummer Block Cast iron 5. Pedal Rubber and stainless steel 6. Transporting wheel PVC Plummer block A Plummer block or bearing housing is a pedestal used to provide support for a rotating shaft with the help of compatible bearings & various accessories. Housing material for a plummer block is typically made of cast iron or cast steel. Table 3.4 Specification of plumber block Sr. No. Name of component 1. Bearing Diameter Dimensions (cm) Transporting wheel It was used for transport the maize shelling machine from one place to another. 28

39 Table 3.5 Specification of transporting wheel Sr. No. Name of compound 1. Transporting wheel Dimensions (cm) Diameter Width Basket Basket was used to carry the maize at the time of shelling of maize. It is made from metal mesh. Miscellaneous materials There were many items which have not been mentioned under any subheading. These were nuts and bolts, steel screws, vulcanized rubber pedals, saddle, stainless steel handle, basket, seat, shelling unit and welding kit (iron and steel) with welding rods Consideration of manufacturing operational The points to be considered for manufacturing operational were the availability of raw material and feasibility of manufacturing operational Design of chain and sprockets The chains were made up of rigid links which were hinged together in order to provide the necessary flexibility for warping around the driving and driven wheels. The wheels had projecting teeth and fit into the corresponding recesses, in the links of the chain. The wheels and the chain were thus constrained to move together without slipping and ensured perfect velocity ratio. The toothed wheels are known as sprockets. The chains were used to transmit motion and power from one shaft to another because the distance between the centers of the shafts was short. Chain drive gave high transmission efficiency as no slippage took place. Pitch (P) of the chain is the distance between the hinge centre of a link and the corresponding hinge centre of the adjacent link. The diameter of the circle on which the hinge centers of the chain lie, when the chain is wrapped round a sprocket is known as pitch circle diameter (d) of the chain sprocket (fig. 3.4). 29

40 Fig. 3.2 Pitch circle diameter of the chain sprocket Since the links of the chain are rigid, therefore pitch of the chain does not lie on the arc of the pitch circle. The pitch length becomes a chord. D = Diameter of the pitch circle, and T = Number of teeth on the sprocket. = (360 /2 ) The exact length of the chain (L)was determined as: T1 = Number of teeth on the larger sprocket, T2 = Number of teeth on the smaller sprocket Where, x= Centre distance between sprockets = ( + 2 ) [ /2 csc(180 / ) /2 csc(180 / ]/ The length of the chain must be equal to an integer number of times the pitch of the chain (Wilson 1986) Design of flywheel A flywheel is an inertial energy-storage device. It absorbs mechanical energy and serves as a reservoir, storing energy during the period when the supply of energy is more than the requirement and releases it during the period when the requirement of energy is more than the supply. The main function of a flywheel is to smoothen out variations in the speed of a shaft caused by torque fluctuations. If the source of the driving torque or load torque is fluctuating in nature, then a flywheel is usually called for. Many machines have load patterns that cause the torque time function to vary over the cycle. Internal combustion engines with one or two cylinders are a typical example. Piston compressors, punch presses, rock crushers etc. are the other systems that have fly wheel. Flywheel absorbs mechanical energy by increasing its angular velocity and delivers the stored energy by decreasing its velocity 30

41 Design Approach There are two stages to the design of a flywheel. First, the amount of energy required for the desired degree of smoothening must be found and the (mass) moment of inertia needed to absorb that energy determined. Then flywheel geometry must be defined that caters the required moment of inertia in a reasonably sized package and is safe against failure at the designed speeds of operation. Design Parameters (Khurmi and Gupta, 2005) Flywheel inertia (size) needed directly depends upon the acceptable changes in the speed. Speed fluctuation The change in the shaft speed during a cycle is called the speed fluctuation and is equal to FI =ωmax ω min We can normalize this to a dimensionless ratio by dividing it by the average or nominal shaft speed (ωave). C S= (ωmax ωmin) /ω Where ω is angular velocity. avg Co-efficient of speed fluctuation The above ratio is termed as coefficient of speed fluctuation Cf and it is defined as C S = (ωmax ωmin) /ω Where ω is nominal angular velocity, and ω the average or mean shaft speed desired. This ave coefficient is a design parameter to be chosen by the designer. The smaller this chosen value, the larger the flywheel have to be and more the cost and weight to be added to the system. However the smaller this value more smoother the operation of the device It is typically set to a value between 0.01 to 0.05 for precision machinery and as high as 0.20 for applications like crusher hammering machinery. Design equation When a flywheel absorbs energy its speed increases and when it gives up energy its speed decreases Let m = Mass of the flywheel in kg, d = Diameter of the flywheel in meters, I = Mass moment of inertia of the flywheel about the axis of rotation in kg-m2 I = d4/64 (i) N = Mean speed during the cycle in r.p.m. = (N1 + N2) / 2 ω= Mean angular speed during the cycle in rad / s = (ω1 + ω2) / 2 We know that mean kinetic energy of the flywheel, 31

42 E = ½ I. ω2 ( in N-m) As the speed of the flywheel changes from ω1 to ω2, the maximum fluctuation of energy, Δ E = Maximum K.E. Minimum K.E. = ½ I. ω2-½ I. ω2.(i) Δ E = I. ω2.cs = m.k2. ω2.cs..(ii) = 2.E.CS The radius of gyration (k) may be taken equal to the mean radius of the rim (R), because the thickness of rim is very small as compared to the diameter of rim. Therefore substituting k = R in equation (ii), we have Δ E = m.r2. ω2.cs... (iii) Assembly drawing preparation Individually designed and manufactured parts were assembled and a final drawing was prepared Detailed drawing of job Detailed drawing of the machine was made by using CorelDraw (version 2007). 3.2 Performance parameters of machine After the machine was made, the testing of the machine was done considering the following parameters: 1. Independent/Operational parameters: I. Moisture Content (%) II. Feed rate (kg/h) 2. Dependent/Response parameters: I. Machine capacity (kg/h) II. Unshelled grain (%) III. Mechanically damaged grain (%) IV. Shelling efficiency (%) V. Cleaned outlet grain (%) Capacity of machine: The shelling capacity was determined as the weight of cobs shelled in an hour, and expressed as kg of cob/h. Unshelled grain: Unshelled grain is defined as the amount of unshelled grain (maize) remains at the cob after the shelling operation. Unshelled grain (%) = ( ) 32

43 Mechanically damaged grain: Mechanically damaged grain (maize) is defined as grain which is damaged by machine during shelling operation. Mechanically damaged grain (%) = ( ) Shelling efficiency: Shelling efficiency is defined as the mass of the kernels actually shelled to the total mass of kernels on the ear before shelling. Shelling efficiency (%) = (100 weight of unshelled grain) Cleaned outlet grain: Cleaned outlet grain is defined as the quantity of maize clean has no damage and unwanted materials. Cleaned outlet grain = ( ) Total grain output = Cleaned grain + damaged grain Sample Preparations Maize (HQPM variety) was provided by the CCSHAU, Regional Research Station Uchani, Karnal, Haryana. The initial moisture content of maize was 7 % (wb). Table 3.6 Morphological characteristics of maize cob Parameters Cob size, cm Variety of maize HQPM Average kernel moisture content at time of tests, % (db) 7 Average number of cobs in 20 kg sample 124 Kernel/pith ratio 4.5 Cob length 19.5 Maximum cob diameter at base end 3.7 Minimum cob diameter at head end 2.8 Average Weight of single cob, g The maize were conditioned to maintain the desire levels moisture content and shelling of cobs were carried out by fabricated pedal operated maize sheller in Pilot plant, 33

44 Department of processing and food engineering, COAE&T, CCSHAU, Hisar. The moisture content of the different maize was measured by hot air oven method. After getting the initial moisture the moisture content of maize, water was added to maintain desired moisture content levels in the maize i.e. 7, 9, 11, 13 and 15, kept for conditioning for 24 h as per the method described by Basediya, et al., (2013) as follows: = Where, { Ww = Weight of water to be added }/((1 )(1 )) Wd = Bone dry weight of raw flour M1= Initial moisture content of flour, % wb in decimal M2= Desired moisture content of flour, % wb in decimal Moisture determination of maize: The moisture is calculated as follows: (as per ISTA, 1986) Procedure Set the oven to pre heat to the required temperature (1030 or 1300) Weight empty container along with lid, (M1) Put the working sample to the weighed container in duplicate and weigh again before drying, (M2) Weighing should be up 3 decimal Remove the lead and place then underneath the container and place in to oven at appropriate temp. And for a required period. Switch off the oven at the end of drying period and transfer to desiccators to cool for 3045 min After cooling weigh the containers with its lid and contents (M3) Moisture content determination: MC (%) = {loss in weight / weight of working sample} x 100 Where; = {( )/ ( )} 100 M1 = Weight of the container along with lid M2 = Weight of the container along with lid and sample before drying M3 = Weight of the container along with lid and sample after drying 3.3 Optimization of operational parameters using Response Surface Methodology Response surface methodology (RSM) was used in designing the experiment (Cochan and Cox, 1957). The central composite rotatable design (CCRD) for the two independent variables was performed. The independent variables considered were shelling disc r.p.m (X1), and moisture content (X2). The independent variables and variation levels are shown in 34

45 Table1. The levels of each variable were established according to literature data and preliminary trials. The outline of experimental design with the actual level is presented in Table 2. Dependent variables were capacity of machine, unshelled grain, mechanically broken grain, shelling efficiency and Cleaned outlet grain of the product responses. Response surface methodology was applied for experimental data, a statistical package of design-expert version 8.01 (Trial version for 30 days) for generation of response surface plots and for statistical analysis of experimental data was used. The results were analyzed by a multiple linear regression method which describes the effects of variables in the models derived. Experimental data were fitted to the selected models and regression coefficients obtained. The analysis of variance (ANOVA) tables were generated for each of the response functions. The individual effect of each variable and also the effects of interaction term in coded levels of variables were determined. Total no. of experiments = 2N+ 2 N+ Central points N = no. of variables Total no. of experiments for three variables = = 13 Five different levels for each experiment in coded form are as follows: -α, -1, 0, +1, +α Where, α = 2N/4 = 1.41 Table 3.7 Independent variables with their range Sr. No. Independent variables 1 Moisture content (%) 2 Speed of operation (r.p.m.) Experimental ranges Levels 7, 9, 11, 13, , 130, 180, 230, Table 3.8 Dependent variables with their range Sr. No Dependent variables Units 1. Capacity of machine kg/h 2. Unshelled grain % 3. Damaged grain % 4. Shelling efficiency % 5. Cleaned outlet grain % Table 3.9 Levels of coded variables Sr. Independent No. Variables Code Coded and actual values Shelling disc r.p.m.(±10) X Moisture content X

46 Table 3.10 Response surface experimental design in terms of coded levels and actual levels Exp. Run Coded value Actual values X1 (Shelling disc, X2 (Moisture r.p.m.) content, %) X1 X

47 Plat 3.1 Ground maize Plat 3.2 Balance (least count) Plate 3.3 Developed maize shelling machine 37

48 CHAPTER-IV RESULTS The results of the study are presented under following subheadings: 4.1 Design and development of pedal operated maize sheller machine. 4.2 Performance evaluation of pedal operated maize sheller machine. 4.3 Optimization of operational parameters using Response Surface Methodology (RSM). 4.1 Design and development of pedal operated maize sheller machine State the purpose To address the problem of shortage of electricity in rural and semi urban areas, manual implement is required. So, a pedal operated maize shelling machine was developed which would be easy to operate and require low maintenance and simultaneously overcome the problems of food safety and hygiene Preliminary sketch and design diagram A preliminary sketch was prepared before the actual designing of the machine to work out the plan (fig 4.1). Schematic diagram showing various dimensions and details are as shown (fig ). Fig 4.1 Preliminary sketch of pedal operated maize shelling machine 38

49 Fig 4.2 Cycle frame of pedal operated maize shelling machine Fig 4.3 Top view of machine 39

50 Fig 4.4 Front view of the machine Fig 4.5 Transmission system of pedal operated maize shelling machine 40

51 Fig. 4.6 Views of the maize shelling machine 41

52 Detailed description of working of pedal operated maize shelling machine The energy required for the pedaling activity in order to run the machine came from the legs, lower back, abdomen and thigh muscles. The person remained seated on the seat and started the pedaling activity with the help of pedals made up of vulcanized rubber. A specially designed seat made up of plastic was provided on the machine itself for the user so that he/she could balance his/her body properly during the activity. The energy from the pedals was transmitted with the help of chain and sprockets made up of cast iron. Iron chain was used as the pedal chain, laid on the sprockets at the pedal end and at the main shaft in the horizontal direction. A stainless steel flywheel was also fitted on this shaft which was used to store rotational energy. It resisted changes in rotational speed and provided continuous energy when the energy source was discontinuous. A set of another chain and sprocket was fixed on this shaft in the vertical direction connecting the shaft and bearing of the shelling unit. A set of transporting wheel also provided for transporting purpose. A transporting handle also connected at the front of machine to run the machine from one place to another place without any problems. The feed i.e. maize was provided with the help of stainless steel hopper which used the force of gravity as the driving force to push the maize towards the shelling assembly. As the person started pedaling activity, the pedal side chain and sprocket drive the main shaft with the help of bearings and in turn the flywheel also started revolving and the rotational energy got stored in it so as to provide a continuous motion to the shaft. The rotating main shaft then in turn rotated another chain and sprocket and with the second chain and sprocket the bearing of the shelling unit started rotated and at the same time shelling unit also. From the reciprocating motion in the assembly maize separated out from the cobs. So, all the respective motions started simultaneously. The shelled maize were then collected at the outlet. 2.1 Principle of operation; The transmission system was provides the primary motion required to power the machine. The motion and torque are transmitted via chain, sprocket and bearings to the shaft attached to the sheller has shelling teeth. The whole maize (together with the cobs) is introduced into the machine through the inlet hopper. They reach the rotating sheller inside the de-cobing teeth by action of sheller. The teeth gave continuous impact force on the whole maize, thereby removing the grains. Because the teeths are arranged in a zig-zag form, the whole maize moves along the length of the sheller in the forward direction until they reach the cob exit spout. Before the whole maize reaches this point, almost all the grains (seeds) was removed. Due to the impact of the teeth some of the cobs may be broken, though both broken and whole exit through the exit spout. The clean maize then run into the receiver where they are collected for further processing operations. 42

53 4.1.3 Consideration of manufacturing operational The points which were considered for the manufacturing operational were the availability of raw material and feasibility of manufacturing operational. Similar works dealing with pedal machines were done by Kajogbola et al. (2010) and Baker et al. (2005) Consideration of size of each member of job and manpower requirement The machine to be developed was aimed for a single person. The total weight of the machine was kg. The following considerations were taken into account: Force required for maize shelling The force required to a single kernel from maize cob ranges = N (Sharma, 2007) Number of grain in a single cob varies = So, force required for one whole maize varies = N Design of Frame Frame was used to as supporting structure to the others parts. Table 4.1 Dimensions of frame Sr. NO Name of compound Dimensions (cm) Solid rods Length 5.08 Width 2.54 Thickness 0.20 Hollow pipes Length Diameter 1.25 Thickness 0.20 Design of sheller Sheller was the part of shelling unit and its function was shelled of the maize. Table 4.2 Dimensions of sheller Sr. NO. Name of compound 1. Sheller 2. Dimensions (cm) Diameter 10 Thickness 1.50 Shelling teeth Pitch 1.25 Height 1 43

54 Design of chain and sprockets Chains and sprockets were used for the transmission of power. One set of chain and sprockets was used at the pedal side and another was used to connect the main shaft to the cam shaft. Design of chain and sprockets: P = Pitch of the sprocket d = Diameter of the pitch circle, and T = Number of teeth on the sprocket. (360 /2 ) =..I) P = 7.2 Sin (1800/18) = 7.2 Sin (100) = = 1.23 cm The exact length of the chain (L) was determined as: = ( + 2 ) [ /2 csc(180 / T1 = Number of teeth on the larger sprocket, ) /2 csc(180 / )]/ T2 = Number of teeth on the smaller sprocket Where, x = Centre distance between sprockets Pedal side chain length: And from eq. (1), L = 1.23(44+18)/ {1.23/2 cosec (180/44) 1.23/2cosec (180/18)/63.6} = {(-1.23)-( )}/63.6 = cm Length of chain connecting main and bearing shaft From eq. (1), L = 1.23(18+9)/ {(1.23/2) cosec (1800/80) /2cosec (1800/9)}/27.5 = {( ) - ( )} = cm The various parameters for the chain and sprockets were calculated and are presented in table Design of flywheel Flywheel A flywheel is an inertial energy-storage device. It absorbs mechanical energy and serves as a reservoir, storing energy during the period when the supply of energy is more than the requirement and releases it during the period when the requirement of energy is more than the supply. Flywheels-Function need and Operation the main function of a flywheel is to smoothen out variations in the speed of a shaft caused by torque fluctuations. If 44

55 the source of the driving torque or load torque is fluctuating in nature, then a flywheel is usually called for. Many machines have load patterns that cause the torque time function to vary over the cycle. Internal combustion engines with one or two cylinders are a typical example. Piston compressors, punch presses, rock crushers etc. are the other systems that have fly wheel. Flywheel absorbs mechanical energy by increasing its angular velocity and delivers the stored energy by decreasing its velocity. Table 4.3 Pedal side chain specifications Sr. No. Specifications Values (cm) 1. Pitch circle diameter (larger sprocket, d1) Pitch circle diameter (smaller sprocket, d2) Number of teeth on larger sprocket (T1) Number of teeth on smaller sprocket (T2) Pitch of chain (p) Centre distance between sprockets (x) Length of chain (L) Table 4.4 Specification of chain connecting main and bearing shaft Sr. No. Specifications Values (cm) 1. Pitch circle diameter (larger sprocket, d1) 2. Pitch circle diameter (smaller sprocket, d2) 4 3. Number of teeth on larger sprocket (T1) Number of teeth on smaller sprocket (T2) 9 5. Pitch of chain (p) Centre distance between sprockets (x) Length of chain (L) Design Approach There are two stages to the design of a flywheel. First, the amount of energy required for the desired degree of smoothening must be found and the (mass) moment of inertia needed to absorb that energy determined. Then flywheel geometry must be defined that caters the required moment of inertia in a reasonably sized package and is safe against failure at the designed speeds of operation. 45

56 Design Parameters Flywheel inertia (size) needed directly depends upon the acceptable changes in the speed. Speed fluctuation The change in the shaft speed during a cycle is called the speed fluctuation and is equal to FI = ω max ω min We can normalize this to a dimensionless ratio by dividing it by the average or nominal shaft speed (ωave). C S= (ωmax ωmin) /ω Where ω is nominal angular velocity. avg Co-efficient of speed fluctuation The above ratio is termed as coefficient of speed fluctuation Cf and it is defined as C S = (ωmax ωmin) /ω Where ω is nominal angular velocity, and ω the average or mean shaft speed desired. This ave coefficient is a design parameter to be chosen by the designer. The smaller this chosen value, the larger the flywheel have to be and more the cost and weight to be added to the system. However the smaller this value more smoother the operation of the device It is typically set to a value between 0.01 to 0.05 for precision machinery and as high as 0.20 for applications like crusher hammering machinery. Design equation When a flywheel absorbs energy its speed increased and when it gives up energy its speed decreased. Let m = Mass of the flywheel in kg, Diameter of the flywheel in meters (d) = 35 cm = 0.35 m I = Mass moment of inertia of the flywheel about the axis of rotation in kg-m2 I = d4/64 (i) = (0.1524)/64) = m N = Mean speed during the cycle in r.p.m. = (N1 + N2) / 2 = (80+280)/2 =180 r.p.m. ω= Mean angular speed during the cycle in rad / s = (ω1 + ω2) / 2 ω1 = 2.. N1 / 60 = / 60 = 8.37 r.p.m. ω2 = 2.. N1 / 60 = / 60 = r.p.m. so, ω = ( )/2 = r.p.m. We know that mean kinetic energy of the flywheel, E = ½ I. ω2 ( in N-m) As the speed of the flywheel changes from ω1 to ω2, the maximum fluctuation of energy, 46

57 Δ E = Maximum K.E. Minimum K.E. Δ E = ½ I. (ω1)2 - ½ I. (ω2)2.(ii) Δ E = ½ 147 (8.37)2-½ (280)2 = 0.23 N-m Δ E = m.r2. ω2.cs.. (iii) The mass of the flywheel rim from equation (iii), m = Δ E / R2. ω2.cs (R = Radius of flywheel) 2 2 = 0.23 / (0.072) (18.83) 0.1 = 1.37 kg And we know, W = mg = = 13.5 kg Table 4.5 Specification of flywheel Sr. No. Name of part 1. Flywheel Specification Diameter (cm) Weight (kg) Floor space requirement The floor space requirement of the machine for working and storage was 9922 cm2 (121 cm 82 cm). 4.2 Performance evaluation of pedal operated maize sheller machine Performance of pedal operated maize sheller was evaluated at different moisture content i.e. 7, 9, 11, 13 and 15 and different speed of operations i.e. 80, 130, 180, 230 and 280. Different machine parameters i.e. Capacity of machine (kg/h), unshelled grain (%), mechanically damaged grain (%), shelling efficiency (%) and Cleaned outlet grain (%) parameters were calculated and shown in table Optimization of the operational parameters using Response surface methodology (RSM) Optimization of the operational parameters aimed at finding the level of intermediate variables viz. capacity of machine, Unshelled grain, mechanically damaged grain, shelling efficiency and Cleaned outlet grain where shelling would be done at minimum moisture content, shelling disc speed and at the same time would result into maximum productivity in terms of quantity of maize shelled. The RSM was applied on pedal operated maize shelling machine and a total of 13 experiments were carried out (fig 4.9). The design layouts with 47

58 results are presented from the table and fig The response surface or contour plots were generated for different interaction of any two independent variables, while keeping the third variable constant. Such three dimensional surfaces give accurate representation and provide useful information about the behavior of the system within the experiment design. Response 1. Capacity of machine (%) Diagnostic checking of fitting model and surface plots for capacity of machine (kg/h) The Model F-value of implies the model is significant. There is only a 0.01% chance that an F-value this large could occur due to noise. Values of "Prob> F" less than indicate model terms are significant. In this case A is a significant model term. Values greater than indicate the model terms are not significant. If there are many insignificant model terms (not counting those required to support hierarchy), model reduction may improve your model. The "Lack of Fit F-value" of implies the Lack of Fit is significant. There is only a 0.01% chance that a "Lack of Fit F-value" this large could occur due to noise. Significant lack of fit is bad -- we want the model to fit. 48

59 Table 4.6 Calculated parameters of machine Exp. Coded value Actual Response parameters values Run X1 X2 X1 X2 Capacity Unshelled Mechanically Shelling Cleaned of grain damaged efficiency outlet machine (%) grain (%) grain (kg/h) (%) (%) Fig. 4.7 Experimental design and data for optimization operational Final Equation in Terms of Coded Factors: Capacity of machine (kg/h) = (9.46 A) (1.30 B) The equation in terms of coded factors can be used to make predictions about the response forgiven levels of each factor. By default, the high levels of the factors are coded as +1 and the low levels of the factors are coded as -1. The coded equation is useful for identifying the relative impact of the factors by comparing the factor coefficients. 49

60 Table 4.7ANOVA for Response Surface Linear model Analysis of variance table [Partial sum of squares - Type III] Source Sum of d.f Squares Mean Square F- P-value Value Model A-Shelling disc r.p.m < B-Moisture content Residual Lack of Fit < Pure Error CorrectedTotal R-Squared Figure 4.8 depicts the interaction shelling disc speed (r.p.m), moisture content and capacity of machine. It is clear from the figure that was found capacity of machine to be minimum at 80 r.p.m and maximum at 280 r.p.m. i.e. as the shelling disc r.p.m increased, capacity of machine also increased and decreased with decreased in shelling disc speed. Whereas, the capacity of machine is minimum at 7 % m.c. and maximum at 15 % i.e. as m.c. content increased, the capacity of machine was also increased and vice- versa. Fig. 4.8 Effect of shelling disc r.p.m and moisture content on capacity of machine 50

61 Response 2. Unshelled grain (%) Diagnostic checking of fitting model and surface plots for unshelled grain The Model F-value of implies the model is significant. There is only a 0.01% chance that an F-value this large could occur due to noise. Values of "Prob> F" less than indicate model terms are significant. In this case A is a significant model term. Values greater than indicate the model terms are not significant. If there are many insignificant model terms (not counting those required to support hierarchy), model reduction may improve your model. Final Equation in Terms of Coded Factors: Unshelled grain (%) = 0.72 (0.33 A) + (0.051 B) The equation in terms of coded factors can be used to make predictions about the response forgiven levels of each factor. By default, the high levels of the factors are coded as +1 and the low levels of the factors are coded as -1. The coded equation is useful for identifying the relative impact of the factors by comparing the factor coefficients. Table 4.8 ANOVA for Response Surface Linear model Analysis of variance table [Partial sum of squares - Type III] Source Sum of d.f Squares Mean F-Value P-value Square Model < A-Shelling disc speed (r.p.m) < B-Moisture content (%) Residual Lack of Fit Pure Error 2.280E E Corrected Total R-Squared Figure 4.9 depicts the interaction shelling disc speed (r.p.m), moisture content and unshelled grain. It is clear from the figure that was found unshelled grain to be minimum at 280 r.p.m and maximum at 80 r.p.m. i.e. as the shelling disc r.p.m increases the quantity of unshelled grain decreased and decreases in shelling disc speed (r.pm) the quantity of 51

62 unshelled grain was increased. Whereas, the unshelled grain decrease with decreased in moisture content and increase with increased in m.c. Fig. 4.9 Effect of shelling disc r.p.m and moisture content on unshelled grain Response 3.Mechanically damaged grain (%) Diagnostic checking of fitting model and surface plots for quantity mechanically damaged grain The Model F-value of implies the model is significant. There is only a 0.11% chance that an F-value this large could occur due to noise. Values of "Prob> F" less than indicate model terms are significant. In this case A, B is significant model terms. Values greater than indicate the model terms are not significant. If there are many insignificant model terms (not counting those required to support hierarchy), model reduction may improve your model. Final Equation in Terms of Coded Factors: Mechanically damaged grain (%) = (0.72 A) + (0.26 B) The equation in terms of coded factors can be used to make predictions about the response for given levels of each factor. By default, the high levels of the factors are coded as +1 and the low levels of the factors are coded as -1. The coded equation is useful for identifying the relative impact of the factors by comparing the factor coefficients. 52

63 Table 4.9 ANOVA for Response Surface Linear model Analysis of variance table [Partial sum of squares - Type III] Source Sum of d.f Squares Mean F-Value P-value Square Model A-Shelling disc speed (r.p.m) B-Moisture content (%) Residual Lack of Fit < Pure Error 2.280E E Corrected Total R-Squared Fig Effect of shelling disc r.p.m and moisture content on mechanically damaged grain Figure 4.10 depicts the interaction between shelling disc speed (r.p.m), moisture content and mechanically damaged grain. It is was found that the quantity of the mechanically damaged grain minimum at 80 r.p.m and maximum at 280 r.p.m. i.e. with increased in shelling disc r.p.m the mechanically damaged grain also increased and vice-versa. Whereas, the quantity of the mechanically damaged grain is minimum at 7 % moisture content and 53

64 maximum at 15 % moisture content i.e. as damaged grain increased with increased in m.c. and vice versa. Response 4.Shelling efficiency (%) Diagnostic checking of fitting model and surface plots for shelling efficiency The Model F-value of implies the model is significant. There is only a 0.01% chance that an F-value this large could occur due to noise. Values of "Prob> F" less than indicate model terms are significant. In this case A is a significant model term. Values greater than indicate the model terms are not significant. If there are many insignificant model terms (not counting those required to support hierarchy), model reduction may improve your model. Table 4.10 ANOVA for Response Surface Linear model Analysis of variance table [Partial sum of squares - Type III] Source Sum of d.f Mean Squares F-Value P-value Square Model < A-Shelling disc r.p.m < B-Moisture content Residual Lack of Fit Pure Error CorrectedTotal R-Squared

65 Fig Effect of shelling disc r.p.m and moisture content on shelling efficiency Final Equation in Terms of Coded Factors: Shelling efficiency (%) = (0.34 A) (0.051 B) The equation in terms of coded factors can be used to make predictions about the response forgiven levels of each factor. By default, the high levels of the factors are coded as +1 and the low levels of the factors are coded as -1. The coded equation is useful for identifying the relative impact of the factors by comparing the factor coefficients. Figure 4.11 depicts the interaction shelling disc speed (r.p.m), moisture content and shelling efficiency. It is clear from the figure that was found shelling efficiency was maximum at 280 and minimum at 80 r.p.m i.e. as shelling efficiency of grain gone increased with increased in shelling disc speed (r.p.m) and vice-versa. Whereas, the shelling efficiency of grain is minimum at 7% moisture content and maximum at 15 % m.c. i.e. shelling efficiency slightly increased with increased in moisture content and vice-versa. Response 5.Cleaned outlet grain (%) Diagnostic checking of fitting model and surface plots for cleaned outlet grain The Model F-value of implies the model is significant. There is only a 0.15% chance that an F-value this large could occur due to noise. Values of "Prob> F" less than indicate model terms are significant. In this case A, A^2 are significant model terms. Values greater than indicate the model terms are not significant. If there are many insignificant model terms (not counting those required to support hierarchy), model reduction may improve your model. 55

66 Table 4.11 ANOVA for Response Surface Quadratic model Analysis of variance table [Partial sum of squares - Type III] Source Sum of d.f Squares Mean F-Value P-value Square Model A-Shelling disc speed (r.p.m) < B-Moisture content (%) AB 4.225E E A B E E Residual E Lack of Fit E Pure Error 2.320E E Corrected Total R-Squared Final Equation in Terms of Coded Factors: Cleaned outlet grain (%) = (0.12 A) + (0.057 B) (0.032 AB) (0.030 A2) (0.011 B2) The equation in terms of coded factors can be used to make predictions about the response for given levels of each factor. By default, the high levels of the factors are coded as +1 and the low levels of the factors are coded as -1. The coded equation is useful for identifying the relative impact of the factors by comparing the factor coefficients. Figure 4.12 depicts the interaction shelling disc speed (r.p.m), moisture content and cleaned grain output. It is clear from the figure that was found cleaned outlet grain gone to increase with increased in shelling disc speed from 80 to 180 r.p.m. after that gone to decreased. Whereas, the cleaned outlet grain of grain is minimum at 7 % moisture content and maximum at 15 % moisture content i.e. cleaned outlet gain was increased with increased in moisture content and vice versa. 56

67 Fig Effect of shelling disc r.p.m and moisture content on Cleaned outlet grain Optimize parameters are: After the optimization of the all response parameters of the machine by RSM the results was found that at shelling disc r.p.m and moisture content 8.17 (%) the capacity of machine and shelling efficiency is maximum i.e and % respectively and mechanically damage is minimum i.e.4.77 %. 57

68 Fig Optimize parameters of machine 58

69 CHAPTER-V DISCUSSION This chapter presents the discussion regarding the findings of the study. 5.1 Design and development of pedal operated maize shelling machine A pedal operated maize shelling machine was designed, developed and tested. The machine was pedal operated and could be operated at various r.p.m manually. The machine was tested at different levels of the moisture contents and different shelling disc speed (r.p.m) had different machine capacity (kg/h), unshelled grains (%), shelling efficiency (%) mechanically damaged grain (%) and cleaned outlet grain (%).The capacity of machine varied from to kg/h at different moisture content and different speed of operation. The capacity of machine was maximum kg/h with maximum shelling efficiency and cleaned outlet grain i.e (%) and (%) respectively and minimum mechanically damaged i.e % at shelling disc r.p.m (180 r.p.m) and moisture content of maize was 9 %. User s acceptability of pedal operated maize shelling machine. The machine was well accepted by majority of the workers as they felt that machine was time saving, labour saving, drudgery saving and simple to operate. They were also satisfied with the working of the machine. Further, there were no injuries to the workers while working on the machine. 5.2 Optimization of the operational parameters using Response surface methodology The main objective for the optimization of operational variables was to get a particular range or numerical values of operating conditions where the dependent variables was best according to the response parameters. Effect of shelling disc speed (r.p.m) and moisture content (%) on capacity of machine (kg/h) 1. The moisture content had no effect on the capacity of pedal operated maize shelling machine. 2. With increase in speed of operation, capacity of the machine had shown a continuous and sharp increased. Capacity of the machine was maximum when the shelling disc r.p.m was maximum and it showed an increasing trend with the increased in speed of operation. Effect of shelling disc speed (r.p.m) and moisture content (%) on mechanically damage grain (%) 1. The mechanically damaged grain increased with increased in moisture content within experimental region. 2. The mechanically damaged grain was maximum when the shelling disc speed (r.p.m) was maximum because shelling disc strike more rapidly with the impact of force on the grain 59

70 cause the broken of grain. It showed an increasing trend with the increased in speed of operation. Similar study reported that kernel moisture content is another factor that has a great influence on kernel damage (Hopkins and Pickard, 1953; Barkstrom, 1955; Goss et al., 1955; Pickard, 1955; Fox, 1959; Brass, 1970; Hall and Johnson, 1970; Mahmoud, 1972). These researchers reported that mechanical kernel damage increased rapidly with increasing moisture content over approximately 20 %. However, Maize shelled at moisture contents considerably below 20 % moisture also suffered high levels of damage. Effect of shelling disc speed (r.p.m) and moisture content (%) on shelling efficiency (%) 1. The shelling efficiency increased with decrease in moisture content and decreased with increase in moisture content. 2. The shelling disc r.p.m had great effect on the shelling efficiency. With the increased in speed of operation, the shelling efficiency increased. It showed an increasing trend with the increased in speed of operation. Similar study conducted by Peprah (1972) hypothesized that spring-mounting the rasp bars of conventional rasp-bar cylinders would reduce damage to kernels during shelling. Laboratory tests were performed in which Maize was shelled with a modified combine cylinder with spring mounted rasp bars (Figure 2.12). Shelling efficiency and percent kernel damage for various spring constants were determined. The test results revealed that the spring-mounted rasp-bar sheller had objectionably low shelling efficiency at low speeds. However, shelling efficiency increased with increasing speed, especially when softer springs were used. Comparative damage studies showed that the spring-mounted rasp-bar sheller had a slightly lower percent damage than the conventional combine cylinder. The percent damage decreased with a decreased in the spring constant and increased with speed. Tiwari et al. (2010) explained operating speed of rotary maize sheller was optimized for its operation at higher operating speeds in pedaling mode, by conducting a simulation study for three sizes of maize cobs at seven operating speeds. The shelling capacity and shelling efficiency of maize sheller for all categories of maize cobs increased curvilinearly with increased in operating speed. Effect of shelling disc speed (r.p.m) and moisture content (%) on cleaned outlet grain (%) 1. The moisture content had not much effect on the cleaned outlet grain of machine. There was small change in increased of cleaned outlet grain with increased in moisture content. 2. With increased in speed of operation cleaned outlet grain was also decreased and with decrease in shelling disc r.p.m it was increased. 60

71 CHAPTER-VI SUMMARY AND CONCLUSION Maize (Zea mays) is one of the most common cereal crop grown in the world. It belongs to a grass family (Gramineae) and originated from Mexico and South America. The plant prefers light (sandy), medium (loamy), and heavy (clay) soils and requires well-drained soil. It cannot grow in the shade and also requires moist soils. The period between planting and harvesting for maize depend upon the variety, but in general the crop physiologically mature 7 to 8 weeks after flowering at that time the kernel contains 35 to 40% moisture and has the maximum content of dry matter. Maize shelling is difficult at a moisture contents above 25%, with this moisture content, grain stripping efficiency is very poor with high operational energy and causing mechanical damage to the seed. It is, after wheat and rice, the most important cereal grain in the world, providing nutrients for humans and animals and serving as a basic raw material for the production of starch, oil and protein, alcoholic beverages, food sweeteners and, more recently, fuel (FAO, 1992).Shelling is the removal or separation of maize grain from the cob and it is an operation that follows the harvest. Maize is shelled traditionally by hands. This is done in such a way that maize is rubbed against another until the grains are removed from the cob, this traditional method of shelling is highly tedious, inefficient and time consuming with low productivity. The existing methods of maize dehusking in agriculture industry consist of breaking the grains by using large machinery for deseeding, both of which are not effective for a developing economy like India where farmers have little money for investment. The power operated maize sheller machine requires electrical energy for its working and its capital investment is also high compared to the conventional methods of shelling but in rural areas supply of electricity is not good at all times. Hence there was a need for an innovative idea or product that is feasible, safe, cost effective and productive for the Indian farmer. Keeping in view the prevailing conditions, a continuous and high capacity pedal operated maize shelling machine was designed, developed and tested by RSM methods. Response surface methodology was adopted for optimization of operational variables. BoxBehnken design was used to analyze and predict the operational variables. The effect of operational variables was studied on response variables. The main criteria for optimization were capacity of machine, mechanically damaged grain and shelling efficiency. The following conclusions were drawn from the study: a) The machine was tested at five levels of moisture content (7, 9, 11, 13, and 15%) and five levels of shelling disc r.p.m (80, 130, 180, 230 and 280) had different machine 61

72 capacity (kg/h), unshelled grains (%), shelling efficiency (%) mechanically damaged grain (%) and cleaned outlet grain (%). The capacity of machine varied from to kg/h at different moisture content and different speed of operation. The capacity of machine was maximum kg/h with maximum shelling efficiency and cleaned outlet grain i.e (%) and (%) respectively and minimum mechanically damaged i.e % at shelling disc r.p.m (180 r.p.m) and moisture content of maize was 9 %. After the optimization of operational parameters of the machine using RSM, the results were found that capacity of machine and shelling efficiency were maximum i.e and % respectively and mechanically damage was minimum i.e % at shelling disc r.p.m and 8.17 % moisture content of maize. b) The moisture content had no effect on the capacity of pedal operated maize shelling machine. c) With increase in speed of operation, capacity of the machine had shown a continuous and sharp increased. Capacity of the machine was maximum when the shelling disc r.p.m was maximum and it showed an increasing trend with the increased in speed of operation. d) The mechanically damaged grain varied from 2.63 to 6.38 %.The mechanically damaged grain increased with increase in moisture content. The mechanically damaged grain was maximum when the shelling disc r.p.m was maximum as shelling disc strike more force on the grain cause broken of the grain and it showed an increasing trend with the increased in speed of operation. e) The shelling efficiency varied from to %.The shelling efficiency increased with decrease in moisture content and decreased with increase in moisture content. The shelling disc r.p.m had great effect on the shelling efficiency. With the increased in speed of operation, the shelling efficiency increased. It showed an increasing trend with the increased in speed of operation. f) The cleaned outlet grain of machine showed not much variation and had approximately 98 % values for all the moisture content and shelling disc r.p.m. The moisture content had not much effect on the cleaned outlet grain of machine. There was small change in increase of cleaned outlet grain with increased in moisture content. With increase in speed of operation, cleaned outlet grain was also decreased and decreased in shelling disc r.p.m, it was increased. 62

73 BIBLIOGRAPHY Adler, Y. P., Markova, E. V. and Granovsky, Y. V. (1975). The design of experiments to find optimal conditions. Mir Publishers, Moscow. Columbus, Ohio. Akubuo C.O. (2002). Performance evaluation of manual maize sheller. University of Nigeria, Nsukka. J. Dep. Agric. Eng. 83(1): Anonymous (2000). Epitome from commissioner of Agriculture. Pune, MH state. Anonymous (2008). Annual report of Directorate of Maize research, New Delhi. Ayres, G. E., Babcock C. E., and Hull D. 0.(1972). Maize combine field performance in Iowa. ASAE Grain Damage Symposium, Agr. Eng. Dept., Ohio State University, Bahaley, S.G., Awate, A.U., & Saharkar, S.V. (2012). Performance analysis of pedal powered multipurpose machine. International Journal of Engineering Research & Technology, 1(5). Barkstrom, R. (1955). Attachments for combining maize.agr. Eng. 36: Basediya A. L., Pandey S., Shivastava S. P., Khan K.A. and Nema A. (2013). Effect of operational and machine parameters on physical properties of extrudate during extrusion cooking of sorghum, horse gram and defatted soy flour blends. Journal Food Science Technology. 50(1): Bharati, K. (1998). Testing and evaluation of locally-made maize sheller. Journal of National Research, Council Thailand. 20 (2). Borchers, I. E. (1943). Maize sheller. U.S. Patent No. 2,325,654 issued Aug. 3, Brass, R. W. (1970). Development of a low damage maize shelling cylinder.unpublished M.S. thesis.library, Iowa State University, Ames, Iowa. Burrough, D. E. and Harbage R. P. (1953). Performance of a maize picker-sheller.agr. Eng. 34: Chand, K., Pandey, R.K., Shahi, N.C. &Lohani, U.C. (2013). Pedal operated integrated potato peeler and slicer. Agricultural Mechanization In Asia, Africa, And Latin America, 44(1) : Cochan, W.G. and Cox, G. M. (1957). Experimental Designs, 2nd edition. John Wiley & Sons, Oxford, UK. Danilo M. (1991). Maize Post-Harvest Operation: Chapter 2. Journal Food Agric. Org. United Nations (FAO), AGST. De, (2005). Energy use in crop production systems in India. Book No.CIAE/2005/2. Central Institute of Agricultural Engineering, Bhopal. DePauw, R. A., Francis R. L. and Snyder H. C. (1977). Engineering aspects of axial-flow combine design. ASAE Paper No i

74 FAO. (1992). Maize in human nutrition.fao Food and Nutrition Series, No.25. Food and Agriculture Organization, Food and Agricultural Organisation (FAO) (2005). Agricultural engineering in development shelling and shelling. Fox, R. E. (1969). Development of compression type maize shelling cylinder.unpublished M.S. thesis. Library, Iowa State University, Ames, Iowa. Freeman, J. E. (1972). Damage factors which affect the value of maize for wet milling. ASAE Grain Damage Symposium, Agr. Eng. Dept., Ohio State University, Columbus, Ohio. Ghadi, A.J. and Kumar A. (2014). Design, development and fabrication of a low cost maize deseeding machine. International Journal of Research in Engineering and Technology 03: Goss, J. R., Bainer R., Curley R. G. and Smeltzer D. G. (1955). Field tests of combines in maize. Agr. Eng. 36: Hall, G. E. and Johnson W. H. (1970). Corn kernel crackage induced by mechanical shelling. ASAE Trans. 13: Halyk, R. M., Stout R. A., and Norris E. R. (1969). A theory impact loading. ASAE Paper No Hassan, A.B., Abolarin, M.S., Olugboji, O.A. and Ugwuoke, I.C. (2009). The design and construction of maize shelling machine. Federal University of Technology. 12(3): Hopkins, D. F. and Pickard G. E. (1953). Maize shelling with a combine cylinder.agr. Eng. 34: indiastat.com/agriculture/2/cerealsandmillets/963995/maize/17199/stats.aspx ISTA. (1996). International rules for seed testing. Seed science and Technology. 24 : Johnston, R. E. (1964). Statistical methods in foundry expts.afs Trans. 72, Kajogbola, R. A., Mustapha, K., Mahamood, M.R. & Iyanda M.O. (2010). Design & development of pedal powered soap mixer, New York Science Journal3(1). Karikatti G., Satish J. J., Anjali K., Roopa L., Sameer S. (2015). Crank Operated Maize Sheller. International Journal for Scientific Research & Development.3: Khurmi, R.S. & Gupta, J.K. (2005). A textbook of machine design. Eurasia Publishing House (Pvt.) Ltd., New Delhi, India Mahmoud, A. R. (1972). Distribution of damage in maize combine cylinder and relationship between physico-rheological properties of shelled grain and damage. Unpublished Ph.D. dissertation. Library, Iowa State University, Ames, Iowa. Maizeell, H. W. (1869). Improvement in maize-shellers. U.S. Patent No. 96,306 issued Nov. 2, ii

75 Morrison, C. S. (1955). Attachments for combining com. Agr. Eng. 35: Nkakini, S.O. (2007). Manually powered continuous flow maize sheller. Applied Energy, Nwakaire, J.N., Ugwuishiwu, B.O. and Ohagwu, C.J. (2011). Design, Construction and performance analysis of a maize thesher for rural dweller. Nigerian Journal of Technology30: Ojomo, A.O., Ale, M.O., and Ogundele, J.O. (2012). Response surface methodology approach to optimizing performance parameters of a locally fabricated maize shelling machine. Journal of Science and Multi-disciplinery Research 04: Oriaku, E.C., Agulanna, C.N., Nwannewuihe, H.U., Onwukwe, M.C. and Adiele, I.D. (2014).Design and performance evaluation of a maize de-cobbing and separating machine engineering.american Journal of Engineering Research. 03: Peprah, I.K.N.E. (1972). Effect of spring-mounted rasp bars on the performance of a shelling cylinder. Unpublished M.S. thesis. Library, Iowa State University, Ames, Iowa. Pickard, G. E. (1955). Laboratory studies in maize combining. Agri. Eng. 36: Sailer, J. M. (1911). Corn sheller. U.S. Patent No. 985,287, issued Feb. 28, Sarma A. (2007). Department of Agricultural and Food Engineering, Indian Institute of Technology, Kharagpur. Shelare S. D., Mali, P.K., Dr. Sakhale C. N. (2015). A Literature Review on Design and Devlopement of Maize Thesher. International Journal of Pure and Applied Research in Engineering and Technology 3 (9), Singh, K.P., Pardeshi, I.L., Kumar, N., Srinivas, K. and Srivastava, A. K. (2008). Optimisation of machine parameters of a pedal-operated paddy thesher using RSM. Biosystems Engineering. (100): Singh, S.P. (2010). Ergonomical interventions in developing hand operated maize dehusker-sheller for farm women. Ph. D. Thesis, CTAE Library, Maharana Pratap University of Agriculture and Technology, Udaipur, RAJASTHAN (INDIA). Skromme, L. K. (1977). Progress report on twin rotor combine concept of rotary shelling and separation. ÀSAE/CIGR International Grain and Forage Harvesting Conference, Iowa State University, Ames, Iowa. Tambari S., Gloria D.O., Diabi O.W., Victor Ayejah (2015). Technical Study on the Design and Construction of a Pedal Powered Hacksaw Cutting Machine. Journal of Mechanical and Civil Engineering. 04: Tiwari, P. S., Pandey, M. M., Gite, L. P. and Shivastava, A. K. (2010). Effect of operating speed and cob size on performance of a rotary maize sheller. International Journal of Research in Engineering and Technology. 47(2): iii

76 Wanjala, N.E. (2014). Design Of A Modified Hand Operated Maize Sheller. University of Nairobi Department of Environmental And Biosystems Eng Wicks, L. J. (1858). Corn shelling machine. U.S. Patent No. 21,288, issued Aug. 24, Young, D. M. (1974). Corn shelling device. U.S. Patent No. 3,844,293, issued Oct. 29, iv

77 Appendix-A Fit Summary Response 1. Capacity of machine (%) Summary (detailed tables shown below) Source Linear Sequential Lack of Fit Adjusted Predicted p-value p-value R-Squared R-Squared < Suggested 2FI < Quadratic < Cubic < Aliased Sequential Model Sum of Squares [Type I] Source Sum of Squares df Mean Square F Value p-value Prob > F Mean vs Total Linear vs Mean 2FI vs Linear Quadratic vs 2FI Cubic vs Quadratic Residual Total Suggested Aliased "Sequential Model Sum of Squares [Type I]": Select the highest order polynomial where the additional terms are significant and the model is not aliased. Lack of Fit Tests Sum of Mean F p-value df Square Value Prob > F Source Squares Linear < FI < Quadratic < Cubic < Pure Error I Suggested Aliased

78 Model Summary Statistics Source Linear Std. Dev R-Squared Adjusted R-Squared Predicted R-Squared PRESS FI Quadratic Cubic Suggested " Aliased" Model Summary Statistics": Focus on the model maximizing the "Adjusted R-Squared" and the "Predicted R-Squared. Anova Response 1. Capacity of machine (kg/h) ANOVA for Response Surface Linear model Std. Dev. Mean C.V. % PRESS 4.56 R-Squared Adj R-Squared Pred R-Squared Adeq Precision Log Likelihood BIC AICc The "Pred R-Squared" of is in reasonable agreement with the "Adj R-Squared" of ; i.e. the difference is less than 0.2. "Adeq Precision" measures the signal to noise ratio. A ratio greater than 4 is desirable. Your ratio of indicates an adequate signal. This model can be used to navigate the design space. Coefficient Standard 95% CI 95% CI Factor Estimate df Error Low High Intercept A-Shelling disc speed (rpm) B-Moisture content (%) II VIF

79 Final Equation in Terms of Coded Factors: Capacity of machine : A 1.30 B The equation in terms of coded factors can be used to make predictions about the response for given levels of each factor. By default, the high levels of the factors are coded as +1 and the low levels of the factors are coded as -1. The coded equation is useful for identifying the relative impact of the factors by comparing the factor coefficients. Final Equation in Terms of Actual Factors: Capacity of machine (kg/h) : [ Shelling disc speed (rpm)] [ Moisture content (%)] The equation in terms of actual factors can be used to make predictions about the response for given levels of each factor. Here, the levels should be specified in the original units for each factor. This equation should not be used to determine the relative impact of each factor because the coefficients are scaled to accommodate the units of each factor and the intercept is not at the center of the design space. Proceed to Diagnostic Plots (the next icon in progression). Be sure to look at the: 1) Normal probability plot of the studentized residuals to check for normality of residuals. 2) Studentized residuals versus predicted values to check for constant error. 3) Externally Studentized Residuals to look for outliers, i.e., influential values. 4) Box-Cox plot for power transformations. III

80 Appendix-B Fit summary Respons 2. Quantity of unshelled grain (%) Summary (detailed tables shown below) Sequential Lack of Fit Adjusted Predicted Source p-value p-value Linear < Quadrati c FI Cubic Lack of Fit Tests Sum of Source Squares df Linear R-Squared R-Squared Mean Square Aliased F p-value Value Prob > F Suggested 2FI Quadratic Cubic Suggested 5.837E E Aliased Pure Error 2.280E E-004 Sequential Model Sum of Squares [Type I] Sum of Source Mean Squares df Square Mean vs Total Linear vs Mean FI vs Linear F p-value Value Prob > F < Suggested 7.225E E Quadratic vs 2FI Cubic vs Quadratic Residual Total Aliased 8.117E E "Sequential Model Sum of Squares [Type I]": Select the highest order polynomial where the additional terms are significant and the model is not aliased. IV

81 Model Summary Statistics Std. Adjusted Predicted Source Dev. R-Squared R-Squared R-Squared PRESS Linear Suggested 2FI Quadratic Aliased Cubic "Model Summary Statistics": Focus on the model maximizing the "Adjusted R-Squared" and the "Predicted R-Squared". Anova Response 2. Quantity of unshelled grain (%) ANOVA for Response Surface Linear model Std. Dev R-Squared Mean 0.72 Adj R-Squared C.V. % Pred R-Squared PRESS 0.28 Adeq Precision Log Likelihood BIC AICc The "Pred R-Squared" of is in reasonable agreement with the "Adj R-Squared" of ; i.e. the difference is less than 0.2. "Adeq Precision" measures the signal to noise ratio. A ratio greater than 4 is desirable. Your ratio of indicates an adequate signal. This model can be used to navigate the design space. Coefficient Factor Standard 95% CI 95% CI Estimate df Error Low High VIF Intercept A-Shelling disc speed (rpm) B-Moisture content (%) V 1.00

82 Final Equation in Terms of Coded Factors: Quantity of unshelled grain (%) = 0.72 (0.33 A) + (0.051 B) The equation in terms of coded factors can be used to make predictions about the response for given levels of each factor. By default, the high levels of the factors are coded as +1 and the low levels of the factors are coded as -1. The coded equation is useful for identifying the relative impact of the factors by comparing the factor coefficients. Final Equation in Terms of Actual Factors: Quantity of unshelled grain (%) = { E Shelling disc speed (rpm)} + { Moisture content (%)} The equation in terms of actual factors can be used to make predictions about the response for given levels of each factor. Here, the levels should be specified in the original units for each factor. This equation should not be used to determine the relative impact of each factor because the coefficients are scaled to accommodate the units of each factor and the intercept is not at the center of the design space. Proceed to Diagnostic Plots (the next icon in progression). Be sure to look at the: 1) Normal probability plot of the studentized residuals to check for normality of residuals. 2) Studentized residuals versus predicted values to check for constant error. 3) Externally Studentized Residuals to look for outliers, i.e., influential values. 4) Box-Cox plot for power transformations. VI

83 Appendix-C Fit summary Response 3. Damaged grain (%) Summary (detailed tables shown below) Sequential Lack of Fit Adjusted Predicted Source p-value p-value R-Squared R-Squared Linear < FI < Quadratic < Cubic < Suggested Aliased Lack of Fit Tests Sum of Mean F p-value Source Squares df Square Value Prob > F Linear < FI < Quadratic < Cubic < Pure Error 2.280E E-004 Suggested Aliased Sequential Model Sum of Squares [Type I] Sum of Mean F p-value Source Squares df Square Value Prob > F Mean vs Total Linear vs Mean FI vs Linear Quadratic vs 2FI Cubic vs Quadratic Residual Total VII Suggested Aliased

84 "Sequential Model Sum of Squares [Type I]": Select the highest order polynomial where the additional terms are significant and the model is not aliased. Model Summary Statistics Std. Adjusted Predicted Source Dev. R-Squared R-Squared R-Squared PRESS Linear Suggested 2FI Quadratic Cubic Aliased "Model Summary Statistics": Focus on the model maximizing the "Adjusted R-Squared" and the "Predicted R-Squared". Anova Response 3. Damaged grain (%) ANOVA for Response Surface Linear model Std. Dev R-Squared Mean 4.62 Adj R-Squared C.V. % Pred R-Squared PRESS 5.44 Adeq Precision Log Likelihood BIC AICc The "Pred R-Squared" of is not as close to the "Adj R-Squared" of as one might normally expect; i.e. the difference is more than 0.2. This may indicate a large block effect or a possible problem with your model and/or data. Things to consider are model reduction, response transformation, outliers, etc. All empirical models should be tested by doing confirmation runs. "Adeq Precision" measures the signal to noise ratio. A ratio greater than 4 is desirable. Your ratio of indicates an adequate signal. This model can be used to navigate the design space. Coefficient Standard 95% CI 95% CI Factor Estimate df Error Low High Intercept A-Shelling disc speed (rpm) B-Moisture content (%) VIII VIF

85 Final Equation in Terms of Coded Factors: Damaged grain (%) = (0.72 A) + (0.26 B) The equation in terms of coded factors can be used to make predictions about the response for given levels of each factor. By default, the high levels of the factors are coded as +1 and the low levels of the factors are coded as -1. The coded equation is useful for identifying the relative impact of the factors by comparing the factor coefficients. Final Equation in Terms of Actual Factors: Damaged grain (%) = [ Shelling disc speed (rpm)] + [ Moisture content (%)] The equation in terms of actual factors can be used to make predictions about the response for given levels of each factor. Here, the levels should be specified in the original units for each factor. This equation should not be used to determine the relative impact of each factor because the coefficients are scaled to accommodate the units of each factor and the intercept is not at the center of the design space. Proceed to Diagnostic Plots (the next icon in progression). Be sure to look at the: 1) Normal probability plot of the studentized residuals to check for normality of residuals. 2) Studentized residuals versus predicted values to check for constant error. 3) Externally Studentized Residuals to look for outliers, i.e., influential values. 4) Box-Cox plot for power transformations. IX

86 Appendix-D Fit summary Response 5. Shelling efficiency (%) Summary (detailed tables shown below) Sequential Lack of Fit Adjusted Predicted Source p-value p-value R-Squared R-Squared Linear < FI Quadratic Cubic Suggested Aliased Sequential Model Sum of Squares [Type I] Sum of Source Squares Mean vs Total df Square F Value Prob > F < Suggested 7.225E E Quadratic vs 2FI E Cubic vs Quadratic Residual Total p-value 1.281E E+005 Linear vs Mean 2FI vs Linear Mean Aliased 9.811E E E "Sequential Model Sum of Squares [Type I]": Select the highest order polynomial where the additional terms are significant and the model is not aliased. Lack of Fit Tests Sum of Mean Source Squares df Square Value Prob > F Linear FI Quadratic Cubic F p-value 7.531E E Pure Error 2.280E E-004 X Suggested Aliased

87 Model Summary Statistics Std. Adjusted Predicted Source Dev. R-Squared R-Squared R-Squared PRESS Linear Suggested 2FI Quadratic Aliased Cubic "Model Summary Statistics": Focus on the model maximizing the "Adjusted RSquared" and the "Predicted R-Squared" Anova Response 4. Shelling efficiency (%) ANOVA for Response Surface Linear model Std. Dev R-Squared Mean Adj R-Squared C.V. % 0.11 Pred R-Squared PRESS 0.24 Adeq Precision Log Likelihood BIC AICc The "Pred R-Squared" of is in reasonable agreement with the "Adj RSquared" of ; i.e. the difference is less than 0.2. "Adeq Precision" measures the signal to noise ratio. A ratio greater than 4 is desirable. Your ratio of indicates an adequate signal. This model can be used to navigate the design space. Coefficient Standard 95% CI 95% CI Factor Estimate df Error Low High Intercept A-Shelling disc speed (rpm) B-Moisture content (%) XI VIF

88 Final Equation in Terms of Coded Factors: Shelling efficiency (%) = (0.34 A) (0.051 B) The equation in terms of coded factors can be used to make predictions about the response for given levels of each factor. By default, the high levels of the factors are coded as +1 and the low levels of the factors are coded as -1. The coded equation is useful for identifying the relative impact of the factors by comparing the factor coefficients. Final Equation in Terms of Actual Factors: Shelling efficiency (%) = [ E 003 Shelling disc speed (rpm)] [ Moisture content (%)] The equation in terms of actual factors can be used to make predictions about the response for given levels of each factor. Here, the levels should be specified in the original units for each factor. This equation should not be used to determine the relative impact of each factor because the coefficients are scaled to accommodate the units of each factor and the intercept is not at the center of the design space. Proceed to Diagnostic Plots (the next icon in progression). Be sure to look at the: 1) Normal probability plot of the studentized residuals to check for normality of residuals. 2) Studentized residuals versus predicted values to check for constant error. 3) Externally Studentized Residuals to look for outliers, i.e., influential values. 4) Box-Cox plot for power transformations. XII

89 Appendix-E Fit summary Response 5. Cleaned outlet grain (%) Summary (detailed tables shown below) Sequential Lack of Fit Adjusted Predicted Source p-value p-value RSquared R-Squared Linear < FI Quadratic Suggested Cubic Aliased Sequential Model Sum of Squares [Type I] Sum of Mean F p-value Square Value Prob > F < FI vs Linear 4.225E E Quadratic vs 2FI Suggested Aliased Source Squares df Mean vs Total 1.269E E+005 Linear vs Mean Cubic vs Quadratic 8.217E E-003 Residual 4.680E E-004 Total 1.269E "Sequential Model Sum of Squares [Type I]": Select the highest order polynomial where the additional terms are significant and the model is not aliased Lack of Fit Tests Sum of Mean F p-value Source Squares df Square Value Prob > F Linear E FI E Quadratic E Suggested 2.360E E Aliased Pure Error 2.320E E-004 Cubic XIII

90 Model Summary Statistics Std. Adjusted Predicted Source Dev. R-Squared R-Squared R-Squared PRESS Linear FI Quadratic Suggested Cubic Aliased "Model Summary Statistics": Focus on the model maximizing the "Adjusted RSquared" and the "Predicted R-Squared". Anova Response 5. Cleaned outlet grain (%) ANOVA for Response Surface Quadratic model Std. Dev R-Squared Mean Adj R-Squared C.V. % Pred R-Squared PRESS 0.10 Adeq Precision Log Likelihood BIC AICc The "Pred R-Squared" of is not as close to the "Adj R-Squared" of as one might normally expect; i.e. the difference is more than 0.2. This may indicate a large block effect or a possible problem with your model and/or data. Things to consider are model reduction, response transformation, outliers, etc. All empirical models should be tested by doing confirmation runs. "Adeq Precision" measures the signal to noise ratio. A ratio greater than 4 is desirable. Your ratio of indicates an adequate signal. This model can be used to navigate the design space. XIV

91 Final Equation in Terms of Coded Factors: Cleaned outlet grain (%) = (0.12 A) + (0.057 B) (0.032 AB) (0.030 A2) (0.011 B2 Coefficient Factor Standard 95% CI Estimate df 95% CI Error Low High VIF Intercept A-Shelling disc speed (rpm) B-Moisture content (%) AB A E E B E The equation in terms of coded factors can be used to make predictions about the response for given levels of each factor. By default, the high levels of the factors are coded as +1 and the low levels of the factors are coded as -1. The coded equation is useful for identifying the relative impact of the factors by comparing the factor coefficients. Final Equation in Terms of Actual Factors: Cleaned outlet grain: E 003 Shelling disc speed (r.p.m.) Moisture content (%) E 004 Shelling disc speed (r.p.m.) Moisture content (%) E 005 Shelling disc speed ( r.p.m.) E 003 Moisture content (%)2 The equation in terms of actual factors can be used to make predictions about the response for given levels of each factor. Here, the levels should be specified in the original units for each factor. This equation should not be used to determine the relative impact of each factor because the coefficients are scaled to accommodate the units of each factor and the intercept is not at the center of the design space. Proceed to Diagnostic Plots (the next icon in progression). Be sure to look at the: 1) Normal probability plot of the studentized residuals to check for normality of residuals. 2) Studentized residuals versus predicted values to check for constant error. 3) Externally Studentized Residuals to look for outliers, i.e., influential values. 4) Box-Cox plot for power transformations. XV

92 ABSTRACT Title of Thesis : Design and Development of Pedal Operated Maize Sheller Name of Degree holder Admission number Title of Degree Name of Discipline Name and address of Major Advisor : : : : : Degree awarding University : VINAY 2014AE04M Master of Technology Processing and Food Engineering Dr. V.K. Singh Assistant Scientist Department of Processing and Food Engineering CCS Haryana Agricultural University, Hisar (Haryana) India. CCS Haryana Agricultural University Hisar (Haryana), India Year of award of Degree Major Subject Total number of pages in Thesis Number of words in the Abstract : : : : 2016 Processing and Food Engineering 62 + iv + XV 251 Key words: Maize sheller, Shelling unit, Pedal operated, Response surface methodology, Optimization, Capacity In India, Maize (Zea mays) is an important crop after the rice and wheat. Many farmers grow maize but could not afford the cost of acquiring some of the imported threshing machines because of their cost. Such people resort to manual means of threshing which results into low efficiency, high level of wastage and exerting of much labor. This machine was constructed to shell maize and separate the cob from the grains. It was constructed from locally available materials and its cost is low and affordable. The operating speed of pedal operated maize sheller was optimized for its operation at higher operating speeds in pedaling mode. Effect of operational parameters of pedal operated maize sheller i.e. shelling disc r.p.m. (80, 130, 150, 230 and 280) and moisture content (7, 9, 11, 13 and 15%) of maize on machine capacity (kg/h), unshelled grain (%), mechanically damaged grain (%), shelling efficiency (%) and cleaned outlet grain (%) were studied. The capacity of machine was maximum kg/h with maximum shelling efficiency and cleaned outlet grain i.e (%) and (%) respectively and minimum mechanically damaged i.e % at shelling disc r.p.m (180 r.p.m) and moisture content of maize was 9 %. After the optimization of operational parameters of the machine using RSM, the results were found that capacity of machine and shelling efficiency were maximum i.e and % respectively and mechanically damage was minimum i.e % at shelling disc r.p.m and 8.17 % moisture content of maize. MAJOR ADVISOR HEAD OF THE DEPARTMENT SIGNATURE OF STUDENT

93 CURRICULUM VITAE Name : VINAY Date of birth : January 15, 1993 Place of birth : Hisar Mother s name : Smt. Jamna Devi Father s name : Sh. Prem Singh Permanent address : H. No.-10, Central Sheep Breeding Farm, P.O.Box-10, Hisar Mobile : ID : vinaythakur38@gmail.com Academic qualifications Sr. Exam Passed No. Board/Univ. Marks Year of obtained Courses Passed completion (%age/ogpa) i) Undergraduate CCS HAU, Hisar /10 Soil water engg., Processing and Food Engineering, Farm power machinery (Agri. Engg.) ii) Post graduation /10 Processing and Food Engineering CCS HAU, Hisar Co-curricular activities attended: NSS Certificate Holder Attended First Aid Camp Participated in Various Games Signature of student