Karaj dam watershed which is the main source of drinking water for the city of Tehran and thesurrounding area has been confronted with a reduction of water quality in the recent years. Ecological land use evaluation using GIS aimed to determining suitability of existent land uses, analysis of 10 years’ (1998-2007) water pollutant averages for determining the river quality and SWOT analysis for recognizing weakness and threats of water quality and strengths and opportunities for its improvement have all been used in this research. The results of these 3 methods have been integrated into a hierarchical process for the zoning of Karaj dam watershed’s polluting potentials. As a result five zones - very few, few, average, high and very high pollution potentials - have been identified. The decision making process for reducing the pollution potential of basin zones may be facilitated by taking into consideration the zoning and the time/budget constraints.

Land use planning is a key and challengable issue in the process of urban comprehencive plans، determining many aspects of future expansion and development of cities. A projected land use table in urban development plans seems a quantitative figure، showing per capita land uses. However، it must have been the results of various studies on population، cultural، social، economic، environmental and physical subjects. Since the issue of per capita land use planning is a base for various urban activities، analysis of this issue is important in a study on land uses analysis. The major aims for determination of per capita land use are to response to the locational and spatial society needs، in the process of rapid urbanization. Per capita land uses are quantitative illustrations of policies، methods and models for land uses، land subdivision، spatial distribution of activities and zonning. It is a key factor affecting construction and population densities، development level، urban design، and city vision. In the process of comprehensive plans provision in Iran، it has been tried to determine per capita land uses in a rational way. However، it has been mainly on the basis of the western literature، or individual and personal perceptions of planners، lacking theoretical and analytical bases. A major challenge in relation to per capita land uses in Iran can be its inconsistencies with various conditions of Iranian cities regarding population، culture، social، economy، environment and climate. In this regard، the relation between per capita land use and city cize is perhaps one of the most important issue to be examined. This is an important subject in Iran، because of Iranain urban hierarcy and city cize situation. The aim of this research is the analysis of per capita land uses in Iranian urban comprehensive plans. The literature on this issue was reviewed and conceptual framework of the sudy was formed. The research method of the study was based on both quantitative and qualitative methods. The relation between per capita land uses and city size was examined and analysed in 40 Iranian urban comprehensive plans. Sampling model and selection of cities was based on two factors، population size and and climate region. For this، 17 samples with less than 100000 population، 8 samples with population between 100000 to 200000، 10 samples with population between 200000 to 500000، 2 samples with population between 1 to 2 millions، and 3 samples with population over 1 million were selected. For correlation relations between city size and per capita، statistical moddeling was used. In the analysis of correlation relations، several softwares were used، including SPSS، Excel، Linear، Logarithmic، Inverse، Quadratic، Cubic، Compound، Power، Growth، and Logistic. Correlations between city size and various land uses were as follow: -0. 346 for residential، -0. 068 for commercial، -0. 317 for educational، -0. 198 for higher education، -0. 320 for health and clinics، -0. 127 for sport، 0. 028 for parks and green spaces، -0. 368 for cultural and religous spaces. Regression and correlation relations showed that there has not been a rational and scientific method for determination of per capita land uses in the selected urban comprehensive plans

این مقاله قصد دارد که با استفاده از تحلیل بارافزون به تحلیل لرزه ای بر مبنای عملکرد پوشش تونل های کم عمقی که در خاک ساخته شده اند و تحت بارگذاری موج برشی قائم قرار گرفته اند بپردازد. تحلیل بارافزون یک تحلیل استاتیک غیرخطی است که بر اساس جابجا کردن جانبی مدل دو بعدی خاک و تونل عمل می کند. این تحلیل تنها مود تغییر شکل اعوجاج (رکینگ) مقطع عرضی پوشش تونل را ارزیابی می کند و نسبت به سایر روش های عددی تحلیل لرزه ای دارای مزیت استفاده از طیف شتاب پاسخ استاندارد نهشته ی خاکی به عنوان تقاضای لرزه ای می باشد. در ابتدا پاسخ یک تونل نمونه بر اثر چهار زلزله به طور جداگانه به وسیله تحلیل بارافزون محاسبه شد. در ادامه روش بکار گیری یک طیف استاندارد نمونه به عنوان تقاضا در تحلیل بارافزون بیان گردید که در آن از طیف استاندارد ساختمان فیما 302 استفاده شد. نتایج تحلیل بارافزون با انجام تحلیل دینامیکی تاریخچه زمانی غیرخطی مورد ارزیابی قرار گرفت و روش تحلیل بارافزون تایید شد. با این وجود برای بکار گیری این روش به مطالعات بیشتری جهت ارائه یک طیف استاندارد قابل قبول، که با طبیعت ژئوتکنیکی نهشته خاکی حاوی تونل کم عمق سازگاری داشته باشد، الزامی است.

This paper presents a failure analysis of journal bearings used in GE-F9 gas turbines. Detailed studies including visual examination, optical microscopy, scanning electron microscopy, XRD and oil analysis were performed to determine the root causes of failure. Based on the results, it was determined that fretting, sulfur attack and fatigue were the main causes of failure.

This paper presents a novel approach for human-machine interface using visual-based communication. Scene analysis، object recognition and tracking، together with gesture detection and classification، are employed to design and implement a system for real time interaction. A new paradigm is proposed for efficient selection of hand gestures that can be used in other gesture-based environments aiming at interactive multimedia. An inexpensive web camera and readily available tools (such as an ordi­nary pen) have been used in this approach to render the system cost effective and suit­able for general and home-based multimedia applications. Focus is placed on real time applications with a fast decision function for gesture classification، and a model-based approach for orientation detection. Experimental results demonstrate the efficacy of the proposed approach when tested using different performance criteria.

This paper proposes a simultaneous approach to manage congestion, evaluate congestion cost, and to allocate this cost among consumers in a short-run market model. The proposed method consists of an iterative algorithm to search and apply a sequence of the best feasible bilateral power exchange among the generators that would optimally reduce and completely remove the congestion. The best exchanges are selected using sensitivity analysis and the AC load flow is used to apply the selected exchange on the system. Congestion cost is calculated using the change in generation cost and divided among the overloaded lines regarding the change in power flow of these lines, after applying the selected exchange. Following each exchange, the costs are allocated to consumers based on the generalized load distribution factors, which are calculated on the system operating condition. The effectiveness of the proposed approach is illustrated in two case studies on the standard IEEE 14 and 118-bus systems, and the results discussed and compared with the other methods in the paper.

Ground Vibration Test (GVT) is one of the standard tests used for designing new aircraft. In this paper, GVT was carried out on an aircraft structure model by the phase separation method. In order to obtain more accurate results, the structure was excited by hammer, random and sine excitations. The results were then used to extract the modal parameters, i.e. natural frequencies, modal damping factors and mode shapes. Extraction algorithms were based on multi-degree of freedom (MDoF) methods where several FRFs are analyzed simultaneously. Correlation between different test techniques was also investigated. Next, a finite element model of the structure was constructed and the theoretical modal analysis results have been compared with experimental ones. The test results obtained from the phase separation technique were also compared with a similar test carried out on the same structure by the phase resonance method. Finally, a cylindrical mass was added to the right tail wing of the model. A new set of modal tests was carried out to investigate the effect of unsymmetry on the modal properties of the structure.