In this research, the aim was to identify the order of the dynamic response of heat production of broiler chickens to steps in air temperature and light intensity. A total of 60 step experiments were performed with air temperature, and 181 step experiments were performed with light intensity. Each step experiment was modeled using a transfer function model. For each experiment, the order of the dynamic heat production response was determined using the Young identification criterion (YIC). Dynamic response of heat production to steps in temperature showed a first–order response in 43 of the 60 experiments (i.e., 72%) and a higher–order response in the other cases (28%). Dynamic response of heat production to steps in light intensity showed a first–order response in 130 of the 181 cases (72%) and a higher–order response in the remaining 51 steps (28%). Based on modeling accuracy in terms of R2, applying the higher–order models improved the accuracy only in a minority (2% to 5%) of the cases. As a conclusion, it can be stated that, in general, the dynamic response of heat production of broiler chickens to step changes in air temperature and light intensity can be modeled assuming first–order dynamics.

Effective and economical techniques to minimize production losses that result from heat stress are important in the broiler industry. Zone cooling, as opposed to whole-house cooling, during hot weather may be effective in relieving heat stress. The present studies seek to determine the effectiveness of such a practice. Two flocks (1 and 2) were raised sequentially for 42 days. Studies were analyzed separately, and when the results of the two studies were consistent, a combined analysis was completed and reported. Means comparison tests were completed on production parameters at harvest (day 42). Cool roost birds showed greater live weight and roost use, lower mortality, and lower feed-to-gain ratios than ambient roost and floor birds, respectively. The parts yield analysis showed that wing weight was greater in the floor-raised birds than in either the cool roost or ambient roost raised birds in flock 1. In flock 2, the cool roost birds showed a greater breast meat weight than the ambient roost birds. The cool roost system appeared to be more efficient at relieving heat stress at temperatures below 30 degrees C than at temperatures above 30 degrees C. Heat loss through the feet of birds ranged between 0.65 and 5.09 watts per bird during week 6 in either flock (chamber air temperature varied from 29 degrees C to 37 degrees C). Moisture condensation on the cool roost system did not significantly increase the litter moisture content in the cool roost treatment beyond that of the ambient roost system.

This article presents a transient 3D CFD model of heat and mass transfer in bulks of chicory roots. The model consists of the system of conservation equations of momentum, energy, and mass for the air phase, and the energy and mass for the product phase without considering the internal gradient in temperature and moisture in the product phase. The interaction between the airflow and the porous media is described by an Ergun-type equation based on experimental data. Heat of respiration is included in the model as an empirically derived function of temperature. A finite volume code is used to solve the model equations. The results show a good agreement between the model and the experiments. Differences between predicted and measured weight loss only amount to a maximum 10% after the initial cooling period. The non-ideal experimental conditions (high velocity, low relative humidity of the air), the various sizes of the products, the small scale of the porous region compared to the size of the product, and the estimation of transfer correlations contribute to the observed differences between experiment and simulation. The model can be applied to study the cooling process in an industrial cold store to find the optimal process settings to improve product quality and reduce product weight loss.

A ground-based remote sensing system (Agricultural Irrigation Imaging System, or AgIIS) was attached to a linear-move irrigation system. The system was used to develop images of a 1-ha field at 1 epsilon 1 m resolution to address issues of spatial scale and to test the ability of a ground-based remote sensing system to separate water and nitrogen stress using the coefficient of variation (CV) for water and nitrogen stress indices. A 2 2 epsilon Latin square water and nitrogen experiment with four replicates was conducted on cotton for this purpose. Treatments included optimal and low nitrogen with optimal and low water. ANOVA was not an adequate method to assess the statistical variation between treatments due to the large number of data points. In general, the coefficient of variation of water and nitrogen stress indices increased with water and nitrogen stress. In fact, the coefficient of variation of stress indices was a more reliable measurement of water and nitrogen status than the mean value of the indices. Differences in coefficient of variation of stress indices between treatments were detectable at 3 m grid resolution and finer for water stress and at 7 m grid resolution and finer for nitrogen stress.

The objectives of this study were to compare relative storability for five pairs of normal–oil content and high–oil content corn (Zea mays) hybrids, and for five pairs of conventional and Bt corn hybrids, stored at 20.C (68.F) and at two different moisture values (19% and 22%, wet basis). Paired hybrids had similar parent genetics. Carbon dioxide production by corn samples was used to calculate dry matter loss (DML), and time to 0.5% DML was used as the primary indicator of storability. Change in the fat acidity content of normal–oil and high–oil corn hybrids was determined and used as another possible indicator of relative storability. The mean adjusted times to 0.5% DML for normal–oil and high–oil corn hybrids were significantly different at a 0.05 probability level for all five hybrid pairs at 19% moisture, but time to 0.5% DML was significantly different for only two hybrid pairs at 22% moisture. The deterioration rate for high–oil corn was faster than for normal–oil corn in most hybrid pairs at both 19% and 22% moisture. Fat acidity values were significantly different at a 0.05 probability level for all hybrid pairs at both moisture levels, both before and after storability tests. Fat acidity values for high–oil corn hybrids were much higher than for comparable normal–oil content corn hybrids after the test. There was a strong positive correlation between oil content and fat acidity after storability tests at both moistures. In general, the high–oil corn hybrids had higher levels of damaged kernels (DKT) at the end of the storability tests, at both 19% and 22% moisture. Fat acidity and DKT results indicate that, at a given moisture content, some high–oil corn hybrids might not store as well as normal–oil content corn. For conventional and Bt corn hybrids, the mean adjusted times to 0.5% DML were significantly different at a 0.05 probability level for three hybrid pairs at 19% moisture and for four hybrid pairs at 22% moisture. In some cases, time to 0.5% DML was greater for the conventional hybrid, and in other cases, time to 0.5% DML was greater for the Bt hybrid. Differences in fungal counts and DKT values after storability tests were small for comparable hybrid pairs of conventional and Bt corn at both moisture levels. These results do not allow any conclusions to be drawn about the relative storability of Bt corn hybrids compared to conventional hybrids.

Water absorption characteristics of wheat and barley during soaking were measured at five temperatures ranging from 10.C to 50.C. From the water absorption characteristic curves, it was determined that water absorption of wheat and barley was in the second falling rate period. Using the measured data, a non–linear least squares method was applied to an approximate solution of the diffusion equation MR = B1 exp(–Kt). Values of parameter B1 for the diffusion model were estimated to be about 0.6 for wheat and about 0.8 for barley. Therefore, the measured data were fitted to the exact solution for the sphere diffusion model for wheat and for the infinite plane sheet diffusion model for barley by a non–linear least squares method. The measured results agreed well with the calculated results. The values determined for the diffusion coefficients were 1.1 . 10(–12) to 1.0 . 10(–11) (m2/s) for wheat and 3.5 . 10(–12) to 3.9 . 10(–11) (m2/s) for barley. An Arrhenius–type equation was used to relate the diffusion coefficient of wheat and barley to temperature (T), and the energy of activation (E) for wheat and barley was estimated. The values determined were 44.0 kJ/mol for wheat and 45.9 kJ/mol for barley.

Recent advancements in low-cost remote sensing equipment and techniques have proven that crop parameter classification can be practical in agricultural situations. One problem still remaining is how to account for in-field variability of mixed ground-cover areas. This study focused on finding a non-invasive method of screening low ground-cover areas before assessing crop nitrogen (N) status. Four years of plot data were used where intense ground sampling was coupled with nadir-viewing remotely sensed data from a ground-based remote sensing system. Data were collected over irrigated corn (Zea mays L.) with both light and dark soil backgrounds to develop a relationship between leaf area index (LAI) and remotely sensed data. An index based on subtracting the red from the green reflectance (green - red) was shown to be strongly related to LAI. A concurrent assessment of the N reflectance index (NRI) over the four-year study indicated that the corn N status classification improved with increasing LAI. Using the (green - red) index and a screening value corresponding to an LAI of 2.5, the data from the four-year study were screened and the NRI was reassessed. The initial screening removed all bare-soil and many of the measurements collected before the V12 growth stage. In this example, 94.0% of the data associated with LAI below 2.5 was correctly filtered out, and 95.4% of the data collected over areas with LAI at or above 2.5 correctly passed the filter. This method of filtering was shown to be highly effective in screening low ground-cover and bare-soil areas before classification. Future incorporation of this technique into on-the-go filtering algorithms could improve crop parameter classification from remotely sensed measurements in early-season and mixed vegetative cover situations.

Biodiesel is a non-toxic, biodegradable and renewable alternative fuel that can be used with little or no engine modifications. Biodiesel is currently expensive but would be more cost effective if it could be produced from low-cost oils (restaurant waste, frying oils, animal fats). These low-cost feedstocks are more challenging to process because they contain high levels of free fatty acids. A process for converting these feedstocks to fuel-grade biodiesel has been developed and described previously. The objective of this study was to investigate the effect of the biodiesel produced from high free fatty acid feedstocks on engine performance and emissions. Two different biodiesels were prepared from animal fat-based yellow grease with 9% free fatty acids and from soybean oil. The neat fuels and their 20% blends with No. 2 diesel fuel were studied at steady-state engine operating conditions in a four-cylinder turbocharged diesel engine. Although both biodiesel fuels provided significant reductions in particulates, carbon monoxide, and unburned hydrocarbons, the oxides of nitrogen increased by 11% and 13% for the yellow grease methyl ester and soybean oil methyl ester, respectively. The conversion of the biodiesel fuel's energy to work was equal to that from diesel fuel.

Agricultural straw is widely used as an erosion mitigation measure on disturbed soils. It has several drawbacks, however, which include increasing intrinsic value, increasing transportation costs, weed source, pesticide residues, and dust. An alternative is wood strands manufactured from small diameter timber or low-value veneer. A study to determine the efficacy of wood strands as an alternative to straw showed that straw and two types of wood strands were equally effective in reducing erosion by over 98%. The authors believe that there are opportunities to exceed the erosion control performance of agricultural straw through the disciplined design of a wood analog. Work is continuing to improve the wood strand properties for further field testing.

Optical coherence tomography (OCT), an imaging modality that uses reflected near-infrared light to generate micron-scale resolution, cross-sectional images of biological tissue, was applied to imaging of various botanical subjects. Example images are given of sectioned kiwifruit, orange flesh, orange peel, lettuce leaves, and intact cranberries. OCT appears to be well suited for botanical imaging; features at the tissue and cellular level in these subjects were well defined. Cranberries were imaged at different stages of ripeness as judged by flesh color, and repeatable differences were seen in the OCT images of ripe and unripe berries. This preliminary study suggests that OCT can be a valuable tool for non-destructive, morphological imaging of botanical subjects.