in the present work, a prototype of a new type of solar collectors, which called direct absorption solar collector, was built and its thermal performance is experimentally compared with conventional flat plate solar collector under transient and steady state conditions. different volume fractions of multi wall carbon nanotubes in water and ethylene glycol mixture (70%:30% in volume) were used a...

in this research calcium fluoride nanoparticles and its different amount of cerium ion dopant (5%and 10%) were prepared. the mentioned nanoparticle were studied by fourier transform infrared spectroscopy (ftir) , x-ray diffraction (xrd), absorption and photoluminescence spectra (pl) and scanning electron microscopy (sem). the xrd patterns indicate a typical cubic fluorite structure and no other...

this research presents a mathematical model for the optimal allocation of oil and gas to different sectors in iran using operations research techniques. sectors are residential, commercial, transportation, industries, agriculture, exports, injection to oil reservoirs and power plants as a secondary energy producer. optimal allocation of energy resources to end-users from 2011 to 2021 has been d...

Magnetorheological elastomer (MRE) is a smart material whose its damping and stiffness characteristics change when exposed to magnetic field. MRE usually contains rubber ferrous particles. Other materials such as additives, can improve physical properties of during cyclic loading. However, limited research has been conducted into the effect incorporating these additives on performance subjected...

Today, due to qualitative growth and scientific advances, energy, especially electricity is increasingly needed by human society. One of the almost endless and pure energy which have been paid attention over the years is the solar energy. Solar cells directly convert solar energy into electrical energy and are one of the main blocks of photovoltaic systems. Significant improvement has been made...

Accelerate the development and utilization of new energy sources, which is basic requirements of implementing the scientific development concept, and building a resource-saving and environment-friendly society, and which has very important meaning for adjusting industrial structure, changing the mode of economic development, expanding employment, and promoting economic society sustainable devel...

Fecal energy excretion was measured by bomb calorimetry, in a group of 30 healthy volunteers and 15 patients with tropical sprue, to determine the absorption of nutrient energy. The mean energy absorption in the healthy volunteers (91.6%) was less than in similar subjects in temperate climates. The reduction of energy absorption in the volunteers, who all have tropical enteropathy, suggests tha...

In the present work, KTP crystals have been grown by spontaneous nucleation technique in flux medium using K6P4O13 flux. 0.4-1 °C/h cooling rates were applied in the spontaneous nucleation process. The presence and amount of impurities has been determined by using XRF. The optical transmission spectra of impure KTP crystals in the UV–visible region are discussed. The transmission cut-off is cle...