AN APPROXIMATE METHOD FOR FATIGUE-LIFE PREDICTION OF FRAMED STRUCTURES

The propagation of fatigue cracks in framed metal structures, usually described by Linear Elastic Fracture Mechanics, is analysed here and described by a numerical method based on classical beam theory. A procedure to be used in practice for the evaluation of stiffness degradation and energy release rate is presented. The procedure uses formulae which are explicitly given for statistically determinate beam structures that are being progressively damaged. If implemented into any beam-oriented finite element code as shown here, the proposed approach allows one to deal also with redundant structures.     

我国钢铁工业能源经济效益分析

在建立起源经济效益和节能经济效益的概念和衡量的方法的基础上，用近年来我国钢铁企业的实际生产数据，研究了重点钢铁企业和地方骨干钢铁企业的能源成本率，能源利润率和成本利润率的变化情况。结果表明，尽管能源成本率的波动都不太大，但能源消耗所创造的利润逐年急剧下降，因而成本利润率也不断下降，而且地方骨干企业尤其。     

影响点火药点火温度的因素及其与能量输出的关系

通过对给定金属，氧化剂体系的ＤＴＡ试验，研究了影响点火药点火温度的因素，说明了它们和点火药能量输出的关系。     

平流双效精馏过程的模拟和优化

对平流双效精馏过程进行了详细研究，建立了最优化设计的数学模型并编制了通用计算机最优化设计程序，用实例对所建立的数学模型及优化设计方法进行了考核计算，发现平流双效精馏节能效果显著，具有很高的应用价值。     

Barriers to the adoption of an energy efficient technology

Solid state electronic ballasts promise significant energy savings in the lighting systems of large buildings. However, organizational factors and standard operating procedures may inhibit the adoption of this technology in the large, bureaucratic public and private sector organizations which represent the major potential users of this technology.     

An experimental study of energy dips for speech and music

Speech signals generally have many intervals with low energy “energy dips”. For music signals, energy dips are not always remarkable. We studied stochastic features of energy dips for speech and music signals. A certain difference was found between the signals in the length of energy dips. Also, the number of energy dips in a time window and their distribution were investigated. From this distribution, a threshold number of energy dips was estimated which provided a scheme for the discrimination of speech from music.     

Investing in energy conservation: Are homeowners passing up high yields?

Energy conservation is examined as an investment option for homeowners. Conservation technologies produce monetary benefits through reduced fuel costs. Calculations suggest that many conservation measures have rates of return significantly higher than alternative investments in stocks, bonds, and real estate, yet the level of conservation activity is inconsistent with these high yields. Several barriers exist which inhibit investments in conservation; it is perceived as risky and the cost of obtaining reliable information is high. Public policies to encourage conservation should focus on reducing the risk of purchasing energy saving devices by improving the accuracy of energy savings estimates.     

Energy dissipation rate and pressure fluctuations in a three phase fluidized bed with a large column diameter

The effects of liquid (0.02-0.10 m/s) and gas (0.0-0.10 m/s) velocities and particle size (1.0, 2.3, 3.0 mm) on the pressure fluctuations and energy dissipation rate in three phase fluidized beds were determined in a large column (0.376 m-I.D.× 2.1 m high). The standard deviation of pressure fluctuations and energy dissipation rate increase with gas and liquid velocities but, decrease in the radial direction of three phase fluidized beds. The energy dissipation rate was well correlated with dimensionless groups as: E_d=16.788Fr ₁ ^0.183 Fr _g ^0.139 (1-ψ)^0.442+1.265Fr _g ^0.143 Re^0.181.     

Secondary ion emission of Fe-Ni alloys in the temperature range including the Curie point

The temperature dependence of secondary ion emission was investigated for Fe-Ni ferromagnetic alloys with different Curie points T_c and elemental composition: 35% Ni 65% Fe (T_c=240°C), 40% Ni 60% Fe (T_c=360°C), and 50% Ni 50% Fe (T_c=530°C). The alloy 79% Ni 16% Fe 5% Mo (T_c=345°C) was also studied. The spatial distribution of Ni⁺ and Fe⁺ secondary ions emitted from the (1 1 1) face of invar and permalloy single crystals was shown to be anisotropic with pronounced ion-yield maximum for both components in the 〈1 1 0〉 directions. The shape of the energy distribution of Ni⁺ and Fe⁺ ions was found to be virtually identical for all the alloys under investigation with a most probable energy at 7 eV and a width at half-maximum of 12 eV. The temperature dependence of the Ni⁺ and Fe⁺ emission has a maximum near the Curie point of the investigated alloys and another maximum at the Curie point of nickel which may indicate the precipitation of nickel into microscopic islands on the surface as a result of heating and sputtering. Auger analysis of the surface composition in the surface layers showed a variation in concentration of oxygen and carbon atoms when Fe-Ni alloys pass from the ferromagnetic to the paramagnetic state and this must affect also the secondary ion emission of alloy components.