Calculation of infrared spectral transmittances of inhomogeneous gases

Calculation of spectral transmittance for a particular inhomogeneous gas path is made by combining known data on gases at constant temperature, pressure, and concentration. The spectral transmittances of the inhomogeneous plume gases is needed to calculate the heat radiated from the exhaust plume to the rocket base of a multiple engine rocket

Wavelength dependence of coherent and incoherent satellite-based lidar measurements of wind velocity and aerosol backscatter

The results are presented of a capability study of Earth orbiting lidar systems, at various wavelengths from 1.06 to 10.6 microns, for the measurement of wind velocity and aerosol backscatter, and for the detection of clouds. Both coherent and incoherent lidar systems were modeled and compared for the aerosol backscatter and cloud detection applications

Application of a single laser Doppler system to the measurement of atmospheric winds

The feasibility of employing a single laser Doppler velocimeter (LDV) system to remotely measure one-, two-, and three-dimensional velocity components in atmospheric flow fields is presented. A focused continuous wave CO2 laser emitting at the 10.6 mu wavelength is used as the laser source. Scan configurations employed by the LDV system were single-point, two-point, conical, and spiral conical. Test results are presented, which include favorable comparisons of velocity components measured by conventional anemometry and the LDV system. The feasibility using a single-beam LDV employing a conical scan technique for measuring two- and three-dimensional mean winds. Measurements to 300 m in dense fogs showed the ability of the LDV system to operate in dense fogs

OPTIMAL CONTROL OF PEST RESISTANCE TO TRANSGENIC CROP VARIETIES

Transgenic corn varieties entered the market in 1996. These plant varieties carry a gene from the soil bacterium Bacillus thuringiensis kurstaki, Bt, that makes the plant produce a toxin deadly to the pest insect European Corn Borer (ECB) Ostrinia nubilalis (Hübner). Since ECB may build up genetic resistance to this toxin, the growers of transgenic corn varieties are required to plant a portion of their field (refuge) with regular corn. This requirement is expected to prolong the efficiency of Bt corn in combating the ECB because some non-resistant pests can survive in the refuge, and thereby dilute the build-up of resistance in the overall pest population. A fixed refuge size of 20 percent is the currently recommended "rule-of-thumb" by the Environmental Protection Agency (EPA). Past work has searched for an economically-optimal refuge size utilizing discrete-time simulation approaches in which refuge size is treated as an exogenous parameter whose optimal value is found through numerical iteration. The objective of this work is to fine-tune parametric refuge specifications by formulating a bioeconomic model capable of endogenously determining the optimal trajectory of refuge sizes over time via an analytical optimal-control rule. The model will provide novel comparative statics/dynamics results demonstrating the sensitivity of the optimal trajectory to important economic and biological parameters.Crop Production/Industries,

Laser Doppler system for measuring three dimensional vector velocity Patent

Describing laser Doppler velicometer for measuring mean velocity and turbulence of fluid flo

Efficiency of N use by wheat as a function of influx and efflux of NO sub 3

Since N assimilation is one of the most costly functions of a plant, its efflux before assimilation results in a serious energy cost and loss in efficiency which could decrease yields. Efficient crop production is critical to the Controlled Ecological Life-Support System (CELSS). The objective is to determine the extent of efflux of the N species NO3(-), NH4(+), NO2(-), and urea after uptake, and possible means of regulation. It was found that NO3(-) efflux became serious as its substrate level increased. Efflux/Influx (E/I) of 3NO3(-) was greater in darkness (35 pct) than in light (14 pct) and the ratio greatly increased with increased substrate NO3(-), (up to 45 pct at 10 mM). It seems advantageous to use the lowest possible nutrient concentration of NO3(-). The feasibility of using ClO3(-) as a trapping agent (competitive inhibitor of NO3(-) uptake) for effluxed NO3(-) was assessed and its toxicity determined

Efficiency of N use by wheat as a function of influx and efflux of NO3

Since N assimilation is one of the most costly functions of a plant, its efflux before assimilation results in a serious energy cost and loss in efficiency which could decrease yields. Efficient crop production is critical to the Closed Ecology Life Support System (CELSS). The objective is to determine the extent of efflux of the N species NO3(-), NH4(+), NO2(-), and urea after uptake, and possible means of regulation. Researchers found that NO3 efflux became serious as its substrate level increased. Efflux/Influx (E/I) of NO3(-) was greater in darkness (35 percent) than in light (14 percent), and the ratio greatly increased with substrate NO3 (-), (up to 45 percent at 10 mM). It seems advantageous to use the lowest possible nutrient concentration of NO3(-). The feasibility of using ClO3(-) was assessed and its toxicity determined

Three dimensional laser Doppler velocimeter turbulence measurements in a pipe flow

The mean and turbulent u, v, and w components of a gaseous fully developed turbulent pipe flow were measured with a laser Doppler velocimeter system. Measurements of important system parameters are presented and discussed in relation to the measurement accuracy. Simultaneous comparisons of the laser Doppler and hot wire anemometer measurements in the turbulent flow provided evidence that the two systems were responding to the same flow phenomena

IRRIGATION DISTRICT ADOPTION OF WATER CONSERVING RATE STRUCTURES

A binary choice model was used to identify the attributes that influence irrigation district adoption of conservation rate structures. Using principles of rate design and irrigation district administration as a framework, measures of irrigation district rate structure objectives and physical and economic conditions were developed. The factors investigated characterize the constraints under which districts operate, value and cost of water, quantity of water delivered and revenue risk for districts. Rate structure adoption was predicted with over 75% accuracy. Both significant and non-significant factors are key to understanding rate choice. Districts were more likely to adopt conservation rate pricing when the cost of water to farmers was greater, higher value crops were grown and in areas with warmer and longer growing seasons. These conditions may be interpreted as reflecting the presence of greater opportunity costs in allocating water between low and higher valued uses. Conservation rate pricing was less likely to be adopted by districts where the proportion of alfalfa to total acreage was higher and with higher per acre deliveries of water. Somewhat surprisingly, annual variation in water deliveries (which should increase the risk of revenue shortfalls) and size of the district (larger districts being more sophisticated) have little bearing on the type of rate structure adopted.Environmental Economics and Policy, Land Economics/Use, Resource /Energy Economics and Policy,

EMERGING AGRICULTURAL WATER CONSERVATION PRICE INCENTIVES

Recent Bureau of Reclamation policies encourage or require irrigation districts to adopt price conservation incentives. Using unpublished survey results and new district-level information, we examine the rate structures and incentives of district water pricing. Our findings reveal that the majority of districts use fixed charges independent of the quantity of water delivered and that most conservation rate structures recently implemented are designed so that the first tier quantity allocation satisfies most crop water needs. Although other district management objectives may be satisfied, price incentives are diminished or nonexistent. The question of whether conservation is being achieved is tautological and depends on how each district defines conservation.Resource /Energy Economics and Policy,