energy consumption is considered as a critical issue in wireless sensor networks (wsns). batteries of sensor nodes have limited power supply which in turn limits services and applications that can be supported by them. an efcient solution to improve energy consumption and even trafc in wsns is data aggregation (da) that can reduce the number of transmissions. two main challenges for da are: (i)...

the method of entropy production minimization for finding energy efficient paths of operation of process equipment is first presented using an instructive example with optimal control theory. with refer-ence to the earlier investigations, the researchers present some design rules that relate to the designs’ en-tropy production. minimum entropy production is not obtained in special cases, not ge...

the aim of this paper is to assess the adaptation of iran’s energy policies to the kyoto protocol. in the past two decades, iran has experienced a considerable increase in greenhouse gas (ghg) emissions; in 2013 it was the world’s ninth largest emitter. although adapting to this protocol in iran’s energy and climate policies seems vital and urgent, its recent status is not promising. this paper...

using photovoltaic systems is gradually expanded by increasing energy demand. abundance and availability of this energy, has turned to one of the most important sources of renewable energy. unfortunately, photovoltaic systems have two big problems: first, those have very low energy conversion efficiency (in act between 12 and 42 percent under certain circumstances). second, the power produced b...

the energy of a graph is equal to the sum of the absolute values of its eigenvalues. two graphs of the same order are said to be equienergetic if their energies are equal. we point out the following two open problems for equienergetic graphs. (1) although it is known that there are numerous pairs of equienergetic, non-cospectral trees, it is not known how to systematically construct any such pa...

long-throated flumes are measurement structures often used in water and wastewater systems to determine the flow discharge. the head-discharge relationship of long-throated flumes is traditionally determined following the critical flow theory and the boundary layer concept. after a review of the traditional approach and an analysis of the approximate assumptions of the boundary layer approach, ...

introduction: ramadan is the holiest month in islamic calendar and muslims abstain from eating, drinking, and smoking from dawn to sunset, in which there are changes in quality of food and eating patterns. the purpose of this study was to know whether these changes provide nutritional needs, and supply all of necessary macronutrients for individuals in the month. method: a prospective observati...

cumin (cuminum cyminum) is an annual suitable for the dry and semi-dry areas of iran. recently, farmers have chosen to plant cumin because it requires less water and growth time. however, at harvest time, the resistance of cumin seed to shatter is low and, if careful attention is not paid to this fact, a major portion of the crop can be lost. when the connection force of the seed decreases, see...

abstract background: biogas is obtained by anaerobic decomposition of organic wastes buried materials used to produce electricity, heat and biofuels. biogas is at the second place for power generation after hydropower and in 2000 about 6% of the world power generation was allocated to biogas. biogas is composed of 40–45 vol% co2, 55–65 vol% ch4, and about 1% non-methanevocs, and non-methane vol...

according to research, between 15 to 20 percent of the total energy consumption of every country is used for residential spaces. this amount is explanatory of the high cost and will follow the destruction of natural resources and environmental demolition. the aim of this research is to recognize earth thermal ability and its usage in public buildings and especially in private buildings in order...