Lecture 7AnnouncementsMoisture Relationships Chpt 3, Pages 79-81Slide 3Slide 4Moisture Relationships Chpt 3, Pages 81-105Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22HW#5 AssignmentSlide 241/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials1Lecture 7Announcements•Lab #1 due Today, 1/31•HW#5 due MONDAY, 2/5•HW#6 due Wednesday, 2/71/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials2Moisture RelationshipsChpt 3, Pages 79-81–Equations:•Conversion–Wet to dry–Dry to wet100100100100wdwdwdMMMMMM� �=� �-� �� �=� �+� �1/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials3Moisture RelationshipsChpt 3, Pages 79-81–Another exampleA bag containing 1.5 kg of popcorn has been stored in the cabinet for a long time. When heated appropriately, only a few kernels popped. Testing showed that the MCw was 9%. Popcorn pops best at 13%. How much water should be added to bring it to this moisture?1/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials4Moisture RelationshipsChpt 3, Pages 79-811/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials5Moisture RelationshipsChpt 3, Pages 81-105–Measuring moisture content•Oven drying…most common•Distillation, chemical reactions, electrical resistance or capacitance, near infrared spectroscopy, nuclear magnetic resonance•Variation due to how water is bound…chemically or physically1/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials6Moisture RelationshipsChpt 3, Pages 81-105–Sampling•Grain probe or trier (trucks or barges)•Diverter sampler (streams of material)•Ellis cup (material on a belt)•Samples divided by a Boerner divider…100-200g samples1/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials7Moisture RelationshipsChpt 3, Pages 81-105–Convection Oven Method•ASAE Standard S352.1, grain and seeds–Numbered dishes are heated for 1 hour–Grain is placed in dishes and in oven–Removed and placed in desiccator to be brought to room temperature and weighed–Heating times and temp vary by material–Wheat, oats, rye…130°C, 19 hr, 22hr, or 16 hr respectively (just an example)1/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials8Moisture RelationshipsChpt 3, Pages 81-105–Chemical method•Karl Fischer method: page 84–Electrical method•Moisture meters•Grain capacitance/conductance meter1/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials9Moisture RelationshipsChpt 3, Pages 81-105–Equilibrium Moisture Content (EMC)•Material moisture content when equilibrium occurs during the exchange of moisture between material and air–Equilibrium Relative Humidity•RH of air when equilibrium occurs–Relationship varies with temperature1/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials10Moisture RelationshipsChpt 3, Pages 81-1051/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials11Moisture RelationshipsChpt 3, Pages 81-1051/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials12Moisture RelationshipsChpt 3, Pages 81-1051/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials13Moisture RelationshipsChpt 3, Pages 81-105•Two equations for predicting EMC–Henderson or modified Henderson Equation–Chung-Pfost equation•Each has 2 forms:–EMC as a function of temperature and MCd–MCd as a function of rel. humidity and temperature1/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials14Moisture RelationshipsChpt 3, Pages 81-105–Modified Henderson:–Chung-Pfost:•K, N, and C are constants specific to materials (Table 3.2, pg 92)1/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials15Moisture RelationshipsChpt 3, Pages 81-105–Modified Henderson:–Chung-Pfost:•A, B, E, F, K, N, and C are constants specific to materials (Table 3.2, pg 92)1/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials16Moisture RelationshipsChpt 3, Pages 81-105–When all you know is the % dry matter as fat and % dry matter as nitrogen free extract (% carb which does not include fiber), use this equation from Vemuganti and Pfost:1/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials17Moisture RelationshipsChpt 3, Pages 81-105–Example:•Using the Modified Henderson and the Chung-Pfost Equations:–Determine the moisture content of rough rice at 20°C and 35% RH1/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials18Moisture RelationshipsChpt 3, Pages 81-1051/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials19Moisture RelationshipsChpt 3, Pages 81-1051/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials20Moisture RelationshipsChpt 3, Pages 81-105–Example:•Using the Modified Henderson and the Chung-Pfost Equations:–If the air temperature is 22°C, what does the rh need to be to dry corn to 15% MCw?1/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials21Moisture RelationshipsChpt 3, Pages 81-1051/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials22Moisture RelationshipsChpt 3, Pages 81-1051/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials23HW#5 AssignmentProblem 1: A grain storage facility in Oklahoma must store canola at 10% mcw or less to prevent molding and rancidity due to the summer temperatures. The facility has 12375 kg at 8% mcw storage. A producer would like to sell 10235 kg of his canola at 15% mcw to the facility. Should the manager of the facility buy this canola to mix with the seed already in storage?Problem 2:A drying system must remove excess moisture content from barley so that the barley will not mold. The barley is placed in the bin at 22% mcw. Safe storage takes place at 13.5% mcw If the bin holds 20,000 bushels, how much water should the drying system remove to achieve the necessary moisture content? (note the conversion necessary for bushels and kg or lbs.)Problem 3:Convert each of the moisture contents listed above to Dry Basis.1/26/07 BAE2022/BAE4400 Physical Properties of Biological Materials24HW#5 AssignmentProblem 4: An aeration equipment manufacturer is designing a system for an elevator facility to dry barley using ambient air aeration. The facility manager wishes to be able to accept 22% mc barley. Generally barley would be harvested in May. The Mesonet says that
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