نتایج جستجو برای: and ground
تعداد نتایج: 16846951 فیلتر نتایج به سال:
Optimization of the sectional wing in ground effect (WIG) has been studied using ahigh order numerical procedure and response surface method (RSM). Initially, the effects of the ground clearance, angle of attack, thickness, and camber of wing have been investigated by a high-resolutionscheme, which is highlystrong and accurate. In the numerical simulation, Normalized Variable Diagram (NVD) sche...
Dynamic Ratcheting (DR) is a nonlinear dynamic phenomenon occurring in hysteretic damping systems. It means the structural plastic deformation increases asymmetrically in successive cycles under an earthquake excitation. Although it is generally recognized that DR is closely related to the frequency contents of an earthquake excitation applied to thestructure, no targeted analysis has bee...
This study investigates the role of man-made disturbance on on nitrogen and phosphorus nutrient storage by herbaceous species in Gall Oak stands of Lorestan province. In order to do this study, two sites with the same physiographic and ecological conditions and different land uses were selected. Multiscale sampling plots were used randomly in each site to collect data on forest floor vegetation...
growing environmental and social concerns, both on the part of decision makers and public opinion, have brought a new perspective to the perception of hazard assessments a valid alternative in the long-term, and an effective complement in short and medium terms, to traditional design procedure for a resistant and safe environment. results of the gradual development of research on the probabilis...
ongoing climate change has been a major global challenge since the 1880s. sequestration of carbon(c) in rangelands ecosystems could provide a net carbon sink to offset increases in atmospheric c in global scale. this research is aimed at estimating the above-ground biomass carbon sequestration potential in iran. for this purpose, total rangelands area and productivity data were extracted from t...
Objective: In recent years, farmers have shown great interest to using native drill planter rather than complex planters to grow vegetables. Methods: In this study, we tested a native planter Independent variables were the two types of substrate surface (asphalt and plowed field), three ground speed (3, 5 and 7 kph) and four types of seeds (tomatoes, onions, radishes and lettuce). Dependent var...
The design of a novel volcano smoke antenna for UWB indoor applications is presented. The design method is based on a general description for the geometry of UWB monopole antennas which is capable of producing most possible shapes for these antennas. It is also compatible with different optimization methods. In addition to a volcano smoke antenna, this method is used to design two optimized mon...
Near-fault ground motions have caused very much damage in the vicinity of seismic sources during recent earthquakes. It is well known that under specific circumstances, intensive ground shakings near fault ruptures may be characterized by short-duration impulsive motions. This pulse-type motion is generally particular to the forward direction, where the fault rupture propagates towards the site...
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