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991.
Wideband multipath measurements at 1300 MHz were made in five factory buildings in Indiana. Root-mean-square delay spread (σ) values were found to range between 30 and 300 ns. Median σ values were 96 ns for line-of-sight paths along aisleways and 105 ns for obstructed paths across aisles. Worst-case σ or 300 ns was measured in a modern open-plan metal-working factory. Delay spreads were not correlated with transmitter-receiver separation or factory topography but were affected by factory inventory, building construction materials, and wall locations. Wideband path loss measurements consistently agreed with continuous-wave measurements made at identical locations. It is shown that such empirical data suggest independent and identical uniform distributions on the phases of resolvable multipath signal components. Average factory path loss was found to be a function of distance to the 2.2 power 相似文献
992.
Utilization of chopped and long alfalfa by dairy heifers 总被引:2,自引:0,他引:2
Two physical forms of alfalfa hay, chopped and long, were fed at maintenance and for ad libitum consumption to dairy heifers to determine effects upon digestibility and energy utilization. Ad libitum intake was associated with lower digestibility of dry matter (56 versus 58%), neutral detergent fiber (45 versus 58%), and acid detergent fiber (45 versus 52%). Energy balance was 1.77 Mcal/day at ad libitum versus .08 Mcal/day at maintenance. Dry matter intake was similar for chopped (5.4 kg/day) versus long alfalfa (5.5 kg/day). Digestibilities of dry matter, neutral detergent fiber, acid detergent fiber, and cellulose were 7 to 10 percentage units lower when heifers were fed the chopped alfalfa. Metabolizable energy intake generally reflected digestible energy intake, which was about 2 Mcal/day less for heifers consuming chopped alfalfa. Heat production was similar for the two physical forms. Consequently, heifers consuming chopped alfalfa had lower energy balance. Reducing particle size of the alfalfa resulted in lower dry matter and energy digestibility, presumably because of increased rate of passage. Increased intake to compensate for depressed energy utilization of the chopped alfalfa did not occur; effects upon animal gain could not be assessed. 相似文献
993.
M. R. MARSHALL T. R. GRAUMLICH R. J. BRADDOCK M. MESSERSMITH 《Journal of food science》1985,50(4):1211-1212
Digestion of citrus wastes by pectolytic and cellulolytic enzymes was compared to the currently employed lime method of solubilizing solids from citrus peel. Maximal soluble solids removed from the pressed peel occurred after 6 hr incubation at 45°C with a pectinase concentration of 1.0 PGu/g peel mixture. Decreasing the particle size of the peel caused a 4 - 10% increase in solids removal after enzyme treatment. Addition of cellulase enzyme (20 CEu/g peel mixture) to pectinase enzyme (1.0 PGu/g peel mixture) removed an additional 15% soluble solids from peel. Glucose, fructose, arabinose, and xylose were the major sugars extracted from enzymetreated peel, while sucrose was the major sugar in lime-treated peel samples. Organic acids (citric, malic, and quinic) were present at higher concentrations in lime-treated peel extracts than in enzymetreated peel extracts. 相似文献
994.
K.G.T. Hollands 《Solar Energy》1985,35(2):131-136
When averaged over many events having the same kt, the average diffuse fraction
carries an important quasi-universal functional dependence
on the clearness index kt. This paper presents a theoretical derivation of k(kt). The atmosphere is modeled as having two homogeneous, nonselectively absorbing layers: an upper layer (roughly, the ozonosphere) with zero scattering and beam transmittance τu, and a lower layer with isotropic, nonselective scattering characterized by an albedo ωl. After an analysis which traces generations of scattered photons, this model predicts a
function which, upon adjusting ωl and τu, fits the measured data closely. 相似文献
995.
Verification of a diffuse pollution model involves comparing results actually observed with those predicted by precise model inputs. Acquisition of precise model inputs is, however, problematic. In particular, when the target catchment is large and substantial estimation uncertainty exists, not only model verification but also prediction is difficult. Therefore, in this study, rice-farming data were collected for all paddy fields from all farmers in a catchment and pesticide adsorption and degradation rates in paddy field soil samples were measured to obtain precise model inputs. The model inputs successfully verified the model's capability to predict pesticide concentrations in river water. Sensitivity analyses of the model inputs elucidated the processes significantly affecting pesticide runoff from rice farms. Pesticide adsorption and degradation rates of the soil did not significantly affect pesticide concentrations, although pesticide discharge to river water accounted for less than 50% of the total quantity of pesticide applied to fields, possibly owing to pesticide adsorption and degradation. The timing of increases in pesticide concentrations in river water was affected mostly by the farming schedule, including the time of pesticide application and irrigation, and secondarily by rainfall events. 相似文献
996.
997.
998.
Zinc and Phytate Distribution in Peas. Influence of Heat Treatment, Germination, pH, Substrate, and Phosphorus on Pea Phytate and Phytase 总被引:1,自引:0,他引:1
The largest proportions of zinc and phytate, 88.7 and 97.1%, respectively, were in the Garfield pea cotyledon; the greatest concentrations were in the germ. Cooking peas by two different methods resulted in 13% phytate reduction. Peas incubated 6.5 hr from 25 to 80°C yielded maximum phytate loss (25%) at 60°C due to phytase activated hydrolysis. Germination (10 d) decreased pea phytate 75% and increased phytase activity 12-fold. Semi-purified germinated pea phytase showed temperature optimum at 45°C, pH optimum of 5.2, 30% inhibition by 1 mM inorganic P, and substrate preference for pyrophosphate. Incubation of early germinated peas at optima pH and temperature is suggested for maximum phytate reduction. 相似文献
999.
T. MATTILA-SANDHOLM T. ALI-VEHMAS G. WIRTANEN U. RÖNNER M. SANDHOLM 《International Journal of Food Science & Technology》1991,26(3):325-336
Automated monitoring of the microbiological quality of heat-processed foods by the resazurin reduction test was applied to microtitration plate incubator-fluorimeter technology. The appearance and disappearance of the fluorescing peak of resorufin was monitored on microtitration trays. Pasteurized or ultra-high temperature-treated starch-based soup was used as the model food system. Bacillus subtilis spores (ultra-high temperature treatment) and vegetative cells of Enterococcus faecalis (pasteurization) were inoculated into the soup before the heat treatment at levels which resulted in some survival. The timing of appearance of maximum fluorescence correlated with the number of bacteria in pre-incubated samples. Automated resazurin-reduction fluorimetry was compared with conventional plating, turbidometry and microcolony count by the direct epifluorescent filter technique. The results of the resazurin test correlated well with those of all the other methods tested. Fluorimetry had the advantage that the results could be read within 1–5h and the reproducibility was superior to the other methods. 相似文献
1000.
Self-organizing communication networks 总被引:3,自引:0,他引:3