T events of September 11, 2001, caused major changes in the lives of Americans, but the full meaning of that day— even as we approach its one-year anniversary—has perhaps not yet been realized. Clearly, the threat of terrorism in all its forms is real. In the medical community, the horrific attacks on New York City and Washington, DC; the thwarted attack on United Airlines Flight 93, which cras...

the zagros forests (west of iran) have been highly exploited in recent decades by human impacts. easy access, abundance and variety of valuable forest yields have led to population growth density, creation of new residential areas and deforestation activities. in order to determinate the distribution and rate of deforestation from 1995 to 2006 by using the satellite imagery (irs-1c and  landsat...

In tissue slices from rapidly expanding internodes of sugar cane the vacuolar invertase level is a function of the balance between synthesis and destruction. The enzyme is destroyed in the tissue at an approximately constant rate with a half time of 2 hours. Invertase synthesis is regulated by both auxin and glucose. From studies with inhibitors of protein and RNA synthesis we conclude that aux...

in this work, tio2 /sio2 (pure anatase), and tio2 /sio2 (anatase/rutile) nano-photocatalysts are prepared by using sol-gel method and control of acidity. the particles size is calculated using scheerer, s equation and is estimated to be around 7-15 nm. in order to improve the photocatalytic activity of tio2 /sio2 ,1% (wt) platinum particles are loaded on both catalysts using photoreductive meth...

The metal-assisted chemical etching (MACE) was used to synthesis silicon nanowires. The effect of etchant concentration, etching and chemical plating time and doping density on silicon nanowires length were investigated. It is held that the increasing of HF and H2O2 concentrations lead to etching rate increment and formation of wire-like structure. The results show that, the appropriate ratio o...

Pulmonary emphysema is a connective tissue disease characterized by the progressive destruction of alveolar walls leading to airspace enlargement and decreased elastic recoil of the lung. However, the relationship between microscopic tissue structure and decline in stiffness of the lung is not well understood. In this study, we developed a 3D computational model of lung tissue in which a pre-st...

Communication and transportation networks are among the most important infrastructures critically involved in the development of different countries. The structural and tectonic position of Iran causes significant damage to its communication networks every year. Therefore, it is essential to adopt an integrated and flexible approach for assessing seismic risk in terms of available indicators. T...

This research is concerned with the design and analysis of a geothermal based multi-generation system by applying both conventional and advanced exergy and exergoeconomic concepts. The proposed energy system consists of a dual-organic Rankine cycle (ORC) to vaporize liquefied natural gas (LNG) and produce electricity. A proton exchange membrane(PEM) electrolyzer is employed to produce hydrogen ...