9,799 research outputs found
A MATHEMATICAL PROGRAMMING MODEL FOR OPTIMAL MANAGEMENT ZONE DELINEATION IN PRECISION AGRICULTURE
The identification of optimal management zones, including optimal uniform grid size, is a complex issue central to the successful implementation of variable rate input application. A novel economic optimization model is developed and applied that identifies the economically optimal management zone. Variable rate seeding can increase profits and reduce risk.Farm Management,
PRODUCTION PRACTICE ALTERNATIVES FOR INCOME AND SUITABLE FIELD DAY RISK MANAGEMENT
Production risk includes yield and days suitable for fieldwork variability. Both were modeled using biophysical simulation and a mean-variance, chance-constrained mathematical programming formulation representing a Kentucky corn, soybean, and wheat producer. While crop diversification, planting date, and maturity group can be used to reduce the types of risk considered, interaction between the two influences how production practices are used to manage risk. For the conditions studied, plant population alterations were less effective for risk reduction of either component. The study provides evidence of the importance of the consideration of both elements of production risk in whole farm planning.days suitable for fieldwork, mathematical programming, risk management, Crop Production/Industries, Risk and Uncertainty,
Shock absorbing mount for electrical components
A shock mount for installing electrical components on circuit boards is described. The shock absorber is made of viscoelastic material which interconnects the electrical components. With this system, shocks imposed on one component of the circuit are not transmitted to other components. A diagram of a typical circuit is provided
Redundant Array Configurations for 21 cm Cosmology
Realizing the potential of 21 cm tomography to statistically probe the
intergalactic medium before and during the Epoch of Reionization requires large
telescopes and precise control of systematics. Next-generation telescopes are
now being designed and built to meet these challenges, drawing lessons from
first-generation experiments that showed the benefits of densely packed, highly
redundant arrays--in which the same mode on the sky is sampled by many antenna
pairs--for achieving high sensitivity, precise calibration, and robust
foreground mitigation. In this work, we focus on the Hydrogen Epoch of
Reionization Array (HERA) as an interferometer with a dense, redundant core
designed following these lessons to be optimized for 21 cm cosmology. We show
how modestly supplementing or modifying a compact design like HERA's can still
deliver high sensitivity while enhancing strategies for calibration and
foreground mitigation. In particular, we compare the imaging capability of
several array configurations, both instantaneously (to address instrumental and
ionospheric effects) and with rotation synthesis (for foreground removal). We
also examine the effects that configuration has on calibratability using
instantaneous redundancy. We find that improved imaging with sub-aperture
sampling via "off-grid" antennas and increased angular resolution via far-flung
"outrigger" antennas is possible with a redundantly calibratable array
configuration.Comment: 19 pages, 11 figures. Revised to match the accepted ApJ versio
PRECISION AGRICULTURE, WHOLE FIELD FARMING AND IRRIGATION PRACTICES: A FINANCIAL RISK ANALYSIS
One of the main advantages of precision agriculture (PA) is its potential to increase profitability by optimizing the productivity of each section of the field. Incorporating irrigation practices to the PA technology could further increase profitability. However, investing in a complete set of precision agriculture (PA) and/or irrigation equipment represents for the average Kentuckian grain producer a substantial investment that can have a significant impact on the financial risk the he/she faces. An analysis of the consequences of that investment on the farm's cash flow and debt to asset ratio is investigated hereCrop Production/Industries,
Precision Timing and Spatial Allocation of Economic Fertilizer Application
Recent increases in fertilizer, particularly nitrogen, and fuel price have resulted in increased production cost for farmers. In this paper a farm level production model that compare uniform and variable rate fertilizer (NPK) application is developed that permits an analysis of the economic performance of fertilizer management regarding profitability. Results show that farmer's exposure to fertilizer and fuel prices risk have substantial impact both on the expected net returns and production practices for producers both uniform and variable rate technology.Q12, Q15, Q55, Crop Production/Industries,
Precision Feeding in Dairy Ration Cost Minimization Under Producer's Risk Management
The biophysical simulation data from Cornell Net Carbohydrate and Protein System were used in non-linear programming model for least cost ration incorporating ingredient nutrient and price variations. Precision feeding practice indicated to have lower mean cost ration than whole herd feeding in terms of ration cost.Non-linear programming, nutrient variation, price variation, precision feeding, environmental pollution, phosphorus, nitrogen, mean cost ration, whole herd feeding, Livestock Production/Industries, Risk and Uncertainty,
Thermoelectric temperature control system for the pushbroom microwave radiometer (PBMR)
A closed loop thermoelectric temperature control system is developed for stabilizing sensitive RF integrated circuits within a microwave radiometer to an accuracy of + or - 0.1 C over a range of ambient conditions from -20 C to +45 C. The dual mode (heating and cooling) control concept utilizes partial thermal isolation of the RF units from an instrument deck which is thermally controlled by thermoelectric coolers and thin film heaters. The temperature control concept is simulated with a thermal analyzer program (MITAS) which consists of 37 nodes and 61 conductors. A full scale thermal mockup is tested in the laboratory at temperatures of 0 C, 21 C, and 45 C to confirm the validity of the control concept. A flight radiometer and temperature control system is successfully flight tested on the NASA Skyvan aircraft
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