724 research outputs found
Documentation requirements for Applications Systems Verification and Transfer projects (ASVTs)
NASA's Application Systems Verification and Transfer Projects (ASVTs) are deliberate efforts to facilitate the transfer of applications of NASA-developed space technology to users such as federal agencies, state and local governments, regional planning groups, public service institutions, and private industry. This study focused on the role of documentation in facilitating technology transfer both to primary users identified during project planning and to others with similar information needs. It was understood that documentation can be used effectively when it is combined with informal (primarily verbal) communication within each user community and with other formal techniques such as organized demonstrations and training programs. Documentation examples from eight ASVT projects and one potential project were examined to give scope to the investigation
Breeding Strategies of the Northern Bobwhite in Marginal Habitat
We studied nesting behavior of radio-tagged northern bobwhite (Colinus virginianus) in south-central Iowa from 1984 to 1988. Female bobwhite incubated 78% of81 clutches where incubation was observed and males incubated 22%. On only 1 occasion were both a male and female observed to incubate the same clutch. Incubation was initiated on 73% of the nests by females before 1 July, while incubation was initiated on 56% of the clutches by males after 1 July. Males hatched 16% of all clutches, first nests by females accounted for 69%, renests for 4%, and second clutches by females that had already hatched 1 clutch for 11 %. Chicks from 3 of the first broods of females that hatched ~l brood survived for ~l week and were not accompanied by other adults. These breeding strategies appear to provide bobwhite populations multiple chances at recruitment in variable environments
Survival Rates for Northern Bobwhites on Two Areas with Different Levels of Harvest
We estimated survival rates for radio-marked northern bobwhites ( Colinus virginianus) in south-central Iowa from I 984 to I 988. Survival rates and survival functions were calculated for 2 areas that received different and varied amounts of hunting pressure. Survival from fall-spring averaged 17.1 % ± 6.9% on the Brown\u27s Slough study area (BSSA) and 20.1 % ± 5.7% on the Millerton study area (MSA). Although these estimates were not different (P = 0.898), the survival functions did differ between the 2 areas (x2 = 25.82, P\u3c0.001). Mortality due to hunting averaged 27.7% ± 8.2% on the BSSA during the fall-spring period and 12.3% ± 4.9% on the MSA. Predators accounted for 52% of fall-spring mortality on the BSSA and 79% of the mortality on the MSA. The BSSA had much lower rates of predation the 2 months following the hunting season. Survival rates during both the spring-fall period and annually did not differ between the 2 areas (P = 0.395 and P = 0.979). Hunting did not appear to be a limiting factor for quail numbers on these areas during the study
Survival Rates of Northern Bobwhite Chicks in South-Central Iowa
We estimated survival rates for radio-tagged northern bobwhite quail chicks (Colinus virginianus) in south-central Iowa from 1986 to 1988. Survival rates and survival functions were calculated for chicks from broods raised by females, broods raised by males and from broods that did not have an adult associated with them. Survival functions differed between broods with hens and those without adults. Predators accounted for almost all of the observed mortality
Experimental determination of grain density function of AZ91/SiC composite with different mass fractions of SiC and undercoolings using heterogeneous nucleation model
The grain density, Nv, in the solid state after solidification of AZ91/SiC composite is a function of maximum undercooling, ΔT, of a liquid alloy. This type of function depends on the characteristics of heterogeneous nucleation sites and number of SiC present in the alloy. The aim of this paper was selection of parameters for the model describing the relationship between the grain density of primary phase and undercooling. This model in connection with model of crystallisation, which is based on chemical elements diffusion and grain interface kinetics, can be used to predict casting quality and its microstructure. Nucleation models have parameters, which exact values are usually not known and sometimes even their physical meaning is under discussion. Those parameters can be obtained after mathematical analysis of the experimental data. The composites with 0, 1, 2, 3 and 4wt.% of SiC particles were prepared. The AZ91 alloy was a matrix of the composite reinforcement SiC particles. This composite was cast to prepare four different thickness plates.They were taken from the region near to the thermocouple, to analyze the undercooling for different composites and thickness plates and its influence on the grain size. The microstructure and thermal analysis gave set of values that connect mass fraction of SiC particles, and undercooling with grain size. These values were used to approximate nucleation model adjustment parameters. Obtained model can be very useful in modelling composites microstructure
Results of the August Roadside Survey for Upland Wildlife in Iowa: 1963-1988
Results of the August roadside survey collected from 1963 through 1988 were examined to determine if trends could be detected in the counts of ring-necked pheasants (Phasianus colchicus), northern bobwhite (Colinus virginianus), gray partridge (Perdix perdix), cottontail rabbits (Sylvilagus floridanus), and white-tailed jackrabbits (Lepus townsendii). The counts also were compared to harvest estimates co determine if correlations exist. Statistically significant linear trends were detected statewide for pheasants, gray partridge and jackrabbits during the 1963 co 1988 period. Trends were downward for all species except gray partridge. During the late 12 years (1977 through 1988), the only significant trend detected was for gray partridge, where counts increased. The survey results also were examined for trends on a regional basis where possible. Significant correlations were found between the mean counts and harvest for all species. For cottontails, however, chis relationship appears to have changed as the correlation of the counts with harvest since 1977 is near zero
Influence of Simulated Harvest on Iowa Wild Turkey Populations
Computer models were used to simulate autumn harvest of a wild turkey (Meleagris gallopava silvestrus) population in Iowa. Parameters were based on estimates of survival rates, fecundity rates, and age and sex ratios from field studies in mixed forest-farmland from 1977 to 1981. Simulations with average survival and fecundity parameters resulted in a population growth rate of 4% per year. If female survival rates were reduced 4.8% or fecundity was reduced 13.9%, the population became stationary. Interaction of hunting and non-hunting mortality was incorporated according to 3 hypotheses: additive, completely compensatory, and compensatory mortality rates up to a threshold. Estimated allowable autumn harvest rates, based on the goal of a stationary breeding population, ranged from 4.7% to 9.5 % of the females and from 14.8% to 28.4% of the males. At these harvest levels, female survival would have to increase approximately 5% and fecundity 16% to compensate for the harvest and return the population to former growth rates. The time required for the total population to decline by 25% of present levels ranged from more than 100 years at 5% harvest rate under additive mortality to almost 74 years at 10% harvest rate under the threshold theory
Modeling of MnS precipitation during the crystallization of grain oriented silicon steel
The process of manganese sulfide formation in the course of grain-oriented silicon steel solidification process is described in the paper. Fine dispersive MnS inclusions are grain growth inhibitors and apart from AlN inclusions they contribute to the formation of a privileged texture, i.e. Goss texture. A computer simulation of a high-silicon steel ingot solidification with the use of author’s software has been performed. Ueshima model was adapted for simulating the 3 % Si steel ingot solidification. The calculations accounted for the back diffusion effect according to Wołczyński equation. The computer simulation results are presented in the form of plots representing the process of steel components segregation in a solidifying ingot and curves illustrating the inclusion separation process
Modelling of non-metallic particles motion process in foundry alloys
The behaviour of non-metallic particles in the selected composites was analysed, in the current study. The calculations of particles floating in liquids differing in viscosity were performed. Simulations based on the Stokes equation were made for spherical SiC particles and additionally the particle size influence on Reynolds number was analysed.The movement of the particles in the liquid metal matrix is strictly connected with the agglomerate formation problem.Some of collisions between non-metallic particles lead to a permanent connection between them. Creation of the two spherical particles and a metallic phase system generates the adhesion force. It was found that the adhesion force mainly depends on the surface tension of the liquid alloy and radius of non-metallic particles
Use of Molybdenum in the Transplant Water for Burley Tobacco
The need for adding molybdenum to tobacco arises because contents in Kentucky soils generally are on the borderline of sufficiency and because amounts of available molybdenum in soil are low when soil pH is low. Soil pH in tobacco fields at midseason often is 0.5 to 1.0 pH unit lower than prior to fertilization. primarily because of the high rates of commercial fertilizers commonly applied to tobacco. This acidity greatly lowers the availability of molybdenum to tobacco plants. That is why we recommend the use of molybdenum when soil pH before fertilization is 6.4 or below
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