Copies of original instruments used for ABET student learning outcome "a" and "e" assessment for the course (ABE 455) (Problems used are highlighted)

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1 Copies of original instruments used for ABET student learning outcome "a" and "e" assessment for the course (ABE 455) (Problems used are highlighted) Homework # 2 Problem 1 Homework # 4 Problems 4&5

2 The University of Arizona Department of Agricultural and Biosystems Engineering ABE/CE 455/555 Fall 2015 Soil and Water Resources Engineering HOMEWORK ASSIGNMENT # 2 DUE: Monday September 14, A snow making machine is to cover 8 ha of blueberries to protect from winter damage. To find: a) If water is available at 20L/min at 0 o C and ambient air at 5 o C will be used to carry away the latent heat of fusion, at what rate (m 3 /s) must air be supplied to prevent the air temperature from rising above 0 o C? b) If the air moves through an orifice 0.4m in diameter, at what velocity will the air exit the orifice? c) If the snow produced has a density 1/6 that of water, how long will it take (days) to cover the 8 ha with 1 cm depth of snow. 2. On a particular date and time, the temperature was 15 o C with 70% rh. To find: Assuming the actual vapor pressure of the air did not change, and that the latent heat of vaporization released during dew formation is sufficient to prevent the night-time temperature from fall further, what temperature do you expect to be reached at night. 3. A 1.4 kw heating element is adding energy to water. At the time the water begins to boil, the room is 25 o C and 75% rh. The dimensions of the room are 4m x 4m x 2.13 m. To find: a) If no air exchange takes place, how long will it take the room to reach 100% rh? b) Air is to be removed from the room by a fan placed above the boiling water. If the air entering the 76.2 mm diameter fan duct is 30 o C and 80% rh., at what rate should the fan remove air (m 3 /min)? Air to make up that leaving the room, enters the room at 25 o C and 75% rh. c) What should be the fan watt rating if the it is assumed to operate at 90% electrical efficiency and 49% fan efficiency?

3 d) If the fan is only 50% efficient in removing the water vapor and the temperature of the inside surface of a window in the room is 20 o C, how long will it take before the window begins to sweat (i.e. dew forms on the window). Assuming that water vapor is distributed evenly throughout the room. 4. Air temperature (dry bulb) of 43 o C and a relative humidity of 10%. To a) What would be the minimum temperature that you might expect the surface of a freely transpiring (evaporating) leaf surface would reach under these conditions? b) What would be the dewpoint temperature for this condition? c) How much water (kg H2O per kg of dry air) would be added if the air were cooled from dry bulb to wet bulb temperature by evaporative cooling?

4 The University of Arizona Department of Agricultural and Biosystems Engineering ABE/CE 455/555 Fall 2015 Soil and Water Resources Engineering HOMEWORK ASSIGNMENT #4 DUE: Friday October 16, 2015 Problem 4.1. A polyethylene sheet is used as a greenhouse covering. The reflectivity of the polyethylene is 0.04 and the absorptivity is Problem 4.2. a) What is the transmissivity? b) If the radiation incident on the plastic is 300 W/m 2, what is the radiation flux entering the greenhouse? A swimming pool 3m wide x 10m long with an average depth of 1.5m in Tucson, Arizona. a) the average daily evaporation from this pool (mm/day) during the month of May b) The average daily evaporation from the same pool during the month of July c.) Which is greater? Why?. Hint: You will need to use weather data from the AZMET files: Note: The equations given in the lecture notes use wind velocities at 7.6m, while those in AZMET are at 2m. To convert from one to the other use the equation: W Z W o Z o height Z. Problem where Wo is the wind speed at height Zo and W is the desired windspeed at The AZMET Weather Data. a) The average daily Penman-Monteith Reference Crop Evapotranspiration at the Campus Ag. Center for May b) How does this compare with the swimming pool evaporation found in problem 4.2?

5 Problem 4.4. Problem 4.5. A cotton crop planted on April 1, 2015 at Maricopa, AZ. Using the crop coefficient curve on slide 28 of lecture #10 and AZMET data for Maricopa, find the crop ET for June 15, 2015 assuming that the base temperature for cotton, Tb, is 55 o F. Note that the crop coefficient curve shows Kc as a function of degree Fahrenheit heat unit accumulation after planting. A maize crop with a plant height of 1m, an LAI of 6, and a minimum stomatal diffusion resistance of 150s/m. On the particular day in question, the net radiation is 500 langleys (cal/cm 2 /day), the average wind speed at 2m is 5 m/s, the temperature is 25 o C and the relative humidity is 40%. Using the Penman-Monteith Equation given as equation 3 in FAO I & D paper # 56 what is the daily ET of this crop in mm/day. Problem 4.6. The meteorological conditions of problem 4.5. a) What is the reference ETo for the hypothetical FAO grass reference for this condition? (Equation 6 in FAO 56) b) If the crop ET is that found in problem 4.5, what is the crop coefficient (Kc) for the maize crop on this particular day?

6 Examples of course instruments/sections of course instruments used for course outcome assessments Homework problems (good, medium, and bad) HW #2 Prob 1 HW #4 Probs 4 & 5

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8 ABE/CE 455/555 Fall 2015 Homework Assignment #2 Brooke Conrardy Question 1 A snow making machine must cover 8 ha (a) At what rate must air be supplied to prevent air T from rising above 0 C (b) At what velocity will air exit an orfice of 0.4m diameter (c ) If snow is 1/6 density of water, how long will it require to cover 8ha to 1cm Solution (a) 20 L/min x 1kg/L x 1min/60s= 1/3 kg/s Latent heat of fusion= 333kJ/kg Energy removed= 333kJ/kg x 1/3kg/s = Enthalpy (-5 C to 0 C)= 10kJ/kg-1kJ/kg 111 kj/s Air Removed= Energy removed/enthalpy= 111kJ/s kg/s 9kJ/kg Rate Air removed (Q)= kg/s*(0.76m^3/kg)= m^3/s (b) Diameter of orifice=0.4m A=pi*(0.4/2)^2= m^2 V=Q/A= m/s (c ) Volume water req= volume water*1/6cm volume water= 8ha*10000m^2/ha*1000L/m^3= vol req=v*(1/600m) Time=Vol/Rate Available= days Homework #2 Prob 1 Medium example no bad examples

9 A cotton crop planted on April 1, 2015 at Maricopa, AZ. Using the crop coefficient curve on slide 28 of lecture #10 and AZMET data for Maricopa, find the crop ET for June 15, 2015 SGDD= 1357 assuming that the base temperature for cotton, Tb, is 55oF. Kc= 1 ET0(in)= 0.37 Etcrop(in)= 0.37 _ = _ Homework #4 Prob 4 Good example no medium or bad examples

10 Problem 4.5 A maize crop with a plant height of 1m, an LAI of 6, and a minimum stomatal diffusion resistance of 150s/m. On the particular day in qu the net radiation is 500 langleys (cal/cm2/day), the average wind speed at 2m is 5 m/s, the temperature is 25oC and the relative humidit Using the Penman-Monteith Equation given as equation 3 in FAO I & D paper # 56 what is the daily ET of this crop in mm/day. Maize crop 1 m LAI 6 minimum stomatal diffusion resistance 150 s / m net radiation ( _ 500 cal/cm2/day = wind speed at 2m 5 m/s Temp air 25 C RH 40 % wet bulb 16.2 C Dew point psy chart cp for air MJ Kg-1 Tucson elevation 806 m λ 2.45 (from FAO 56) Rn MJ/m^2/day =( ( _ )+ (( _ _ ))/ _ )/( + (1+ _ / _ )) _ =(0.408 ( _ )+ 900/( +273) _2 ( _ _ ))/( + ( _2)) _ =(ln [( _ )/ _ ] ln [( _h )/ _( h) ])/( ^2 _ ) =2/3h _ =0.123 =( _ ) _( h)=0.1 Zom _ = _1/( _ ) d =.67 Zoh =.0123 Zom =.123 _ =1.01( +273) _ =1.01(25+273)= =( _ )/( )= ^( 3) _ =(ln [(2 0.67)/0.123] ln [(2 0.67)/0.0123])/( (0.41) ^2 2)= / =101.3(( )/293)^5.26 _ =150/6=25 / =101.3 (( )/293 )^5.26=92.13 Assume h = 2 m T =25 Y =.061 kpa C -1 esa ^ ( )= exp [(17.27 = ^ (25)= 3.17 kpa Kpa C^-1 _ = ^ ( = )= exp [( kpa =( ( _ )+ (( _ _ ))/ _ )/( + (1+ _ / _ )) pa =(0.189( ) "0013 " ET 5.46 mm/day HW #4 Prob 5 good example

11 A maize crop with a plant height of 1m, an LAI of 6, and a minimum stomatal diffusion resistance of 150s/m. On the particular day in question, the net radiation is 500 langleys (cal/cm2/day), the average wind speed at 2m is 5 m/s, the temperature is 25oC and the relative humidity is 40%. Using the Penman-Monteith Equation given as equation 3 in FAO I & D paper # 56 what is the daily ET of this crop in mm/day. LAI= 6 rs(s/m)= 150 e sa ea rc(s/m)= 25 (Rn G) acp u2(m/s)= 5 ra ET Tdb( C)= 25 o r Rn(MJ/m^2/day)= s 1 h(m)= 1 ra d(m)= 0.67 T( C)= 25 zom(m)= 0.12 e0(25 C)(kPa)= 3.17 zoh(m)= 0.01 Since Tmax and Tmin are not given, it will be assumed that es is approximately e0. zm=zh(m)= 2 Tdew( C)= 10.9 k= 0.41 ea(10.9 C)(kPa)= 1.3 ra= 13.3 Δ(kPa/ C)= 0.19 Elevation(ft)= cp(mj/kg* C)= 1.01E-03 P(kPa)= 90.0 ra(kg/m^3)= 1.2 γ= λet0(mm/day)= 4.32 HW # 4 Prob 5 medium example

12 Problem 5 A maize crop with a plant height of 1m, an LAI of 6, and a minimum stomatal diffusion resistance of 150s/m. On the particular day in question, the net radiation is 500 langleys (cal/cm2/day), the average wind speed at 2m is 5 m/s, the temperature is 25oC and the relative humidity is 40%. Using the Penman-Monteith Equation given as equation 3 in FAO I & D paper # 56 what is the daily ET of this crop in mm/day. Solution: Lecture #23 slide 5 Canopy resistance rc= rs/laieff efflai is affected by percentage of sunlit leaves EFFLAI = LAI= 6 since it is a short corn crop (1m) find actual ET since you are given all parameters. HW #4 Prob 5 Bad example