Effect of wind turbine generator model and siting on wind power changes out of large WECS arrays

Methods of reducing the WECS generation change through selection of the wind turbine model for each site, selection of an appropriate siting configuration, and wind array controls are discussed. An analysis of wind generation change from an echelon and a farm for passage of a thunderstorm is presented. Reduction of the wind generation change over ten minutes is shown to reduce the increase in spinning reserve, unloadable generation and load following requirements on unit commitment when significant WECS generation is present and the farm penetration constraint is satisfied. Controls on the blade pitch angle of all wind turbines in an array or a battery control are shown to reduce both the wind generation change out of an array and the effective farm penetration in anticipation of a storm so that the farm penetration constraint may be satisfied

Understanding Muslim Technoscientific Identities

With Islamic resurgence, there has been an increased concern that science and technology are not valuefree agents that can be appropriated and expropriated without inducing social and cultural violence. There is a complex relationship between culture, religion and society on the one side, and science and technology on the other, that is far from being value free. The way people understand and adopt this relationship between culture, science, and technology, can be termed 'technoscientific identities'. This relationship has seldom been explored in the Islamic world

The effect of terrain factors on landslide features along forest road

The objective of this study was to investigate the effects of physiographic features such as slope, altitude, aspect and soil on landslides dimensions and distribution in Pahnehkola forest, north of Iran. 30 landslides were selected for detailed observation, with their occurrences recorded by global positioning system (GPS) along the surveyed forest road. Then, landslides were mapped in Arc view and subsequently digitized into a geographic information system (GIS). Results indicate that the landslide area at a distance of 80 to 100 m from road edge was significantly more than that of other distances. The landslide dimensions increased with increasing slope angle. The mean of landslide area and mean of landslide volume on the Northwest aspect was significantly more than that on other aspects (P<0.01). The mean of landslide dimensions in altitude class of 400 to 650 m was significantly less than that in altitude class of 150 to 400 m (P<0.01). The mean of landslide dimensions increased significantly with increasing soil liquid and plastic limit. The logistic regression modeling indicate that independent variables including aspect, liquid limit, plastic limit and soil moisture, significantly influence the landslides area. The majority of landslides were situated along roads and on faults, and shallow landslides were more frequent along roads compared to those on faults.Key words: Landslide, forest road, physiographic features, GPS, Pahnehkola forest

Evaluating Physical Properties of Potato by a Combined Tillage Machine

Abstract: Potato is a complete and cheap food and can be considered as a source of starch. It medical, industrial and other usages have increased its importance. One the most important things about potato from customer's point of view is it appearance. Because its improper shapes raise problems for re-planting and other uses. One of the most important factors that affect shape and other properties of potato is soil preparation practices prior to seeding. Thus through experiments at educational farm located in Khurasegan Islamic Azad University, in form of complete random tests, four treatments of plows, moldboard, chisel, disk, and a new one made by Iran Plow Tools (a combination of chisel and disk plows), in three repetitions were compared. Parts of harvested products from each device's farm were divided and then tested. Through several experiments, skin area averages, tubers weight, tubers size, tubers quantity, and product performance (output) were measured and by a statistical analysis method were compared. In comparing products from moldboard plow and Iran Plow Tools' plow no significant differences were observed in tubers size and product performance, but for tubers quantity and tubers weight averages, the differences were significant. In comparing the new plow with other tested plows for above mentioned factors, mostly the differences were significant. Briefly, the results show that by means of the new combined plow, more uniform products can be obtained and it is a proper choice to replace moldboard plow nationwide. [Nature and Science 2010;8(11):66-70]. (ISSN: 1545-0740)

Planning road network in mountain forests using GIS and Analytic Hierarchical Process (AHP)

Forest road construction is the most costly operation in forestry. Road designing and construction in unsuitable areas may increase construction and maintenance costs and also cause many environmental impacts. Therefore, it is required to pay more attention to forest road design. In this research, we tried to introduce an appropriate method for locating forest roads using GIS and AHP simultaneously. The most important layers in locating forest road include slope, soils type, geology, hydrographic networks, aspects, trees volume m3 per hectare ,tree type and elevation maps which were determined and then by using expert thought and AHP method the study area was classified in five classes including very good, good, medium, bad and worse for forest road construction. Then two new variants were designed on the prepared AHP map: the first variant was designated using traditional method and Pegger extension was applied to design the second. Pegger Planning variant (PP_variant) had the highest efficiency in path from good and bad points of view based on AHP map. The results of this study illustrated that using AHP and GIS simultaneously can introduce an appropriate and suitable method in the forest road network planning

Atmospheric Error Correction of the Laser Beam Ranging

Atmospheric models based on surface measurements of pressure, temperature, and relative humidity have been used to increase the laser ranging accuracy by ray tracing. Atmospheric refraction can cause significant errors in laser ranging systems. Through the present research, the atmospheric effects on the laser beam were investigated by using the principles of laser ranging. Atmospheric correction was calculated for 0.532, 1.3, and 10.6 micron wavelengths through the weather conditions of Tehran, Isfahan, and Bushehr in Iran since March 2012 to March 2013. Through the present research the atmospheric correction was computed for meteorological data in base of monthly mean. Of course, the meteorological data were received from meteorological stations in Tehran, Isfahan, and Bushehr. Atmospheric correction was calculated for 11, 100, and 200 kilometers laser beam propagations under 30°, 60°, and 90° rising angles for each propagation. The results of the study showed that in the same months and beam emission angles, the atmospheric correction was most accurate for 10.6 micron wavelength. The laser ranging error was decreased by increasing the laser emission angle. The atmospheric correction with two Marini-Murray and Mendes-Pavlis models for 0.532 nm was compared