نشریه انرژی ایران
سال هشتم شماره 1 (پیاپی 29، بهمن 1381)

A preliminary process concept has been developed for methane to ethylene conversion via OCM reactions based on the fixed bed reactor technology. The effects of catalyst performance parameters including methane conversion per pass(XCH4)and C2+ selectivity(SC2+) and ethylene/ethane ratio in the reactor effluent on the capital and operating costs of the process has been estimated quantitatively.The economic impact of possible utilization of different type of inert gases(e.g.,steam and/or methane)and implementing the fluidized bed technology in the process have also been discussed

The use of insulating material in envelope of a residential building reduces the total amount of annual cooling-heating loads. This is affected by two factors: the insulation thickness, and the configuration of installation of the insulation. In the present study effect of configuration and distribution of a 5 centimeters styro-foam insulation in a 20 centimeters thickness concrete walls and roofs is investigated. The climatic condition are chosen as of Tehran city (as moderate climate), and Tabriz city (as cool climate), and Ahwaaz city (as hot climate). The results show that use of insulation material in buildings of these cities reduces the annual loads 64-72% approximately. The reduction of annual loads depends on the insulation configuration.

Since the first experiments with plasma focus facilities in 1960's. These devices are known as intense sources of neutron when the working gas contains deuterium with a proper density. Most of the emitted neutrons are produced by D-D reactions, but the mechanism of these reactions is not still clear completely. In this paper, the results of experimental investigations of neutron emission characteristics in "Dena" plasma focus facility (Filippov type, 90 kJ, 25 kV) over a range of discharge voltages and pressures are presented. Out working gases are D2 & D2+%1 Kr, two different conic and flat insert anodes were employed. We have simultaneously measured the total emissions in our experiments for analyzing the neutron generation mechanism in this device. We have found the upper & lower pressure limits and the optimum pressure for neutron generation, and we have observed the double pluses structure of neutron signal for the first time in this device. Form the experimental results, it seems that both thermonuclear & no thermonuclear mechanisms are always present in neutron generation, but their contribution in the total yield is strongly dependent on experimental conditions (initial pressure, discharge voltage, gas admixture, etc.) It was found that the range of variation of total neutron yield and neutron emission anisotropy factor for experiments with D2+%1 Kr is wider than experiments with D2, and the best neutron emission results belongs to discharges in D2+%1 Kr with a conic insert anode. By employing D2+%1 Kr with a conic insert anode, and varying pressure between 0.3-2 torr at a discharge voltage of 16 kV, it can be deduced that in low pressures (<0.5 torr) the role of beam - target interaction mechanism in neutron production is important, and its importance decreases with pressure, around the optimum pressure (0.86 torr) the GPM mechanism has the major effect on neutron generation, and at high pressures the thermonuclear mechanism plays the major role. Furthermore, the behavior of the neutron yield and anisotropy factor with discharge energy at a pressure near optimum (0.84 torr) was studied and it was found that at low energies anisotropy factor is relatively high and decreases sharply by increasing the energy, From the experimental results, the? index in the empirical neutron yield scaling law was found about 3.62 for D2 +%1 Kr and 3 for D2.

Due to limitation of fossil fuel resources, other renewable sources of energy such as hydro plants have found wide spread application. However, in countries where limited hydro potentials are widely available, micro hydro plants have strongly attracted attentions. The very main application of micro hydros is in the rural areas where end users of electricity are far from the electricity net work that by no means the extension of the net work can be economically justified. Agnew micro hydro is an axial flow, 45? Kaplan turbine. Due to presence of thousands of limited potentials in Iran, a joint project on redesigning and development of Agnew turbine was under taken between Iranian Research Organization for Science and Technology (IROST) and the Glasgow university. For Undertaking this project a test laboratory was designed and prepared at IROST. Test results showed a 23% increase of the best performance of the turbine. In this article, the turbine and the test rig have been briefly introduced and the test results are presented

Available solar radiation potential is the primary condition for any solar energy applications in any region. In this article attempt is made to evaluate solar radiation intensity at Yasooj which located 30? 50? north latitude about south central parts of Iran. Metrological data and climate condition from 1988 to 1997 is used to apply different correlations and daily solar irradiation during the years is determined. It was found that average a clear index is about 0.6 which shows nearly clear sky condition for this location.