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In a previous study, we investigated the effect of additions of 10, 15, and 20% water (on a weight basis) to snow at an initial temperature of -11°C on the energy required for compaction. Water-addition of 10% significantly reduced the amount of energy required to compact snow. Here, we describe the compressive characteristics of snow at water-addition levels of 0, 3, 6, 9, and 12% and initial snow...
This study focuses on the issue of whether fluctuations in the price of crude oil have affected employment and the rate of unemployment in the U.S. After reviewing previous assessments of the issue, the existence of an empirical relationship between the rate of unemployment and crude oil price volatility is established using tests for cointegration. Subsequently, the nature of the relationship is...
We present monthly-average maximum, minimum and mean temperatures and the medians of extreme temperatures for 24 weather stations in Saudi Arabia. Heating-degree days are also given for these locations.
Variations of collection efficiencies and pressure drops through bag filters have been investigated experimentally. It was found that the collection efficiencies decreased exponentially or linearly with increases of particle diameter or dust loading, respectively; they increased exponentially with the filter surface area, were found to be independent of dust-particle material and filtration velocity,...
The objective of this study was to investigate the patterns of energy use and their relationship with crop production on farms in the Dera Ismail Khan (D.I. Khan) District of the North West Frontier Province, Pakistan. A year-long survey of daily inputs of energy to more than 600 crop plots of 26 farms in seven villages was carried out. These represented both rainfed and irrigated farms operated...
We present a thermodynamic analysis of the Maloney and Robertson and the Kalina absorption power cycles. The maximum power for specified external conditions is identified and used as a reference to evaluate the performance of these two absorption power cycles. The evaluation focuses on power cycles operating with low temperature heat sources such as geothermal heat, solar energy or waste heat.
We present the results of an Austrian appliance turn-in program and document major performance features. This program is of interest because it was launched in 1989 and was the first comprehensive rebate program for household appliances in Europe. Although not a state-of-the-art design, the program provides useful insights and performance data.
Monthly-average hourly data for global and diffuse solar radiation on a horizontal surface in Gebze were measured for the period 1984-1992. A statistical procedure has been employed to develop a correlation of monthly-average hourly global and diffuse solar radiation to clearness-index. Results have been compared with an equation which was proposed by Liu and Jordan.
We have gathered and analysed energy-consumption data in the residential sector in Hong Kong. We surveyed 200 households in 5 different classes of residential units. Sub-sector and end-use electricity consumption have been estimated. Major electricity-consuming items are room air-conditioners, lighting and refrigerators. Ownership levels of most essential and common electrical appliances are above...
We have analysed the performance of a greenhouse suitable for use in the summer season when the temperature inside the greenhouse may have to be reduced for optimum plant growth. Cooling was achieved by integrating the earth via an air tunnel with the greenhouse in a forced-circulation mode. This technique also reduces irrigation requirements. The selection of optimum design parameters is described.
Modified expressions for the heat-transfer fluxes at the interface of a solid surface and a gas are given for different Knudsen-number regimes. These expressions for diatomic gases contain both a gas-reflection and a thermal accommodation coefficient. Parallel-plate, coaxial-cylindrical and concentric-spherical surfaces are considered. A general expression for the thermal accommodation coefficient...
Energy analysis, data and research are reviewed. Methods to determine the energy required to maintain the structures of industrial organizations are described. Results for six organizations reconfirm earlier findings: (i) there are diseconomies of scale, i.e. smaller firms are more energy efficient (in Btu/employee-year) in maintaining structure than are larger firms; (ii) private-sector firms are...
We consider the effects of operating variables on SO x emissions in unstaged combustion with a stainless steel combustor that is 2 m high and has a 0.3 m 0.3 m square cross section. Fluidizing air was supplied through a multihole distributor. The experiments were carried out for fluidizing velocities of 1-2 m/sec, bed temperatures of 830-880°C, 20-40% excess air, and bed particle sizes...
We develop a pricing model for electric power service that accounts for customers' reliability preferences as well as the randomness of outages in the power-supply system. The model combines features of both reliability pricing and real-time pricing. A production cost simulation submodel is used to estimate expected total and marginal production costs on an hourly basis, as well as system reliability...
We examine various systems for the recovery of thermal energy from waste gases and for preheating in blast-furnace Cowper stoves, with the basic aim of improving efficiencies when utilizing blast-furnace gas with low net heating value at constant peak temperature. Using first- and second-law analyses, with suitably defined exergetic quantities, numerical values are given to measure energy savings.
Although thermal-energy storage (TES) systems for peak-load shifting are now in the market, very few performance testing and evaluation procedures have been developed. Measurements were made to quantify space-cooling, space-heating, and domestic water-heating but the emphasis was on space-cooling performance of the unit. The TES system was tested over a wide range of indoor and outdoor conditions...
The performance of an endoreversible regenerative Brayton heat engine has been studied. The analysis is focused on minimizing irreversibilities associated with the hot and cold heat exchangers and regenerator.
The energy efficiency of tobacco-curing practice in Tanzania is investigated. A one-quarter size laboratory model of a traditional, fuelwood-fired, rural barn is used. The energy consumed in the tobacco-curing process is monitored together with emissions of CO and CO 2 . An average of 14 kg of fuelwood is consumed to obtain 1 kg of cured tobacco. The emission of CO is 0.6% of total volume...
There has been a recent growth of interest in the potential for using straw as an energy source to generate electricity and/or heat. The energy balance of this process is important as a measure of the sustainability of such an activity, while the CO 2 emitted and that saved by offsetting the need to produce energy by other means are also important, given the U.K.'s obligations to reduce CO...
We present a new methodology for obtaining optimum values of the integrated cost of utility investment with customer interruption in distribution planning for electric power systems by determining the reliability cost and worth of the distribution system. Reliability cost refers to investment cost of the utility in achieving a defined level of reliability. Reliability worth is the benefit gained...
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