nowadays, energy plays an important role in the economic and community development of country. consequently, performance analysis of energy systems is one of the effective methods being used to prevent waste of energy resources. among the different power generation technologies, steam power plants make a significant contribution to power generation in iran, with a share of 47 % of electricity g...

Environmental Health Perspectives • volume 119 | number 7 | July 2011 A 283 acquiesced to that point in a reply to the first of several letters to the editor by Brondum (2007) on the same topic. However, Braun et al. (2007) noted that including such information is not always possible when, for example, the use of National Health and Nutrition Examination Survey (NHANES) data or other constraint...

Analysts agree about the need for developing both new and cleaner energy resources. At the same time, some argue that energy efficiency can provide only a minimal role in meeting future energy needs. Hence, energy supply is encouraged while energy efficiency is supported only minimally. Analysts Douglas Lightfoot and Christopher Green suggest in a series of papers, for example, that there are p...

Increasing energy end-use efficiency—technologically providing more desired service per unit of delivered energy consumed—is generally the largest, least expensive, most benign, most quickly deployable, least visible, least understood, and most neglected way to provide energy services. The 46% drop in U.S. energy intensity (primary energy consumption per dollar of real GDP) during 1975–2005 rep...

p. 396, col. 2, full para. 2 ("Perhaps..."): The vehicle efficiency stated is from a simulation of on-road performance, obtained by multiplying each vector in the standard EPA test cycles by 1.3. The equivalent EPA adjusted efficiency (the kind used for official efficiency ratings and shown on the window stickers of market vehicles) is 2.06 L-equivalent per 100 km, 48.5 km/L-equivalent, or 114 ...

www.sciencemag.org SCIENCE VOL 325 14 AUGUST 2009 785 COVER Pulsars in our Galaxy newly discovered by the Fermi Gamma-ray Space Telescope, launched in June 2008. The objects emit broad gamma-ray beams that have enabled Fermi to locate a never-before-seen population. Fermi has also seen pulsars with millisecond periods and has detected at least one globular cluster (center left). See the Researc...

OS resource management policies traditionally employ buffering to “smooth out” fluctuations in resource demand. By minimizing the length of idle periods and the level of contention during non-idle periods, such smoothing tends to maximize overall throughput and minimize the latency of individual requests. For certain important devices, however (disks, network interfaces, or even computational e...