نتایج جستجو برای ' UES '

 This paper consists of two sections. In the first section an efficient method is used for decomposition of the canonical matrices associated with repetitive structures. For this purpose, cylindrical coordinate system, as well as a special numbering scheme is employed.In the second section the results of this method is compared with the results of the methods which MATLAB software used to compute eigenvalues. In order to illustratethe efficiency of the aforementioned methods, repetitive str...

 Site layout planning is a significant but relatively ignored work on construction site, which has been treated improperly as somewhat routine. It is known that the complex interrelationship of material, equipment, laborers, space, environment, assess road, surrounding buildings, and building types affect the productivity and efficiency of a construction process. This complexity was inhibiting the smooth flow of resources especially when many trade contractors were working simultaneously on...

 Accurate and rapid assessment of the as-built status on any construction site provides the opportunity to understand the current performance of a project easily and quickly. Rapid project assessment further identifies discrepancies between the as-built and as-planned progress, and facilitates decision making on the necessary remedial actions. Currently, manual visual observations and surveying are the most dominant data capturing techniques but they are time-consuming, error-prone, and inf...

 Phase Change Materials (PCMs) are increasingly being used in the area of energy sustainability. Thermal characterization is a prerequisite for any reliable utilization of these materials. Current characterization methods including the well-known T-history method depend on accurate temperature measurements. This paper investigates the impact of different thermistor linearization techniques on the temperature uncertainty in the T-history characterization of PCMs. Thermistor sensors and two l...

Exhaust Gas Recycle (EGR) is an interesting technique, which is more and more adopted in spark-ignition engines in order to reduce both NOx emissions and fuel consumption in certain engine operating points. A fraction of exhaust gases recycled to the intake produces a significant charge dilution which decreases the combustion chamber temperature and, as a consequence, the NO formation rates. Furthermore, charge dilution allows reducing pumping losses at part load and heat losses through the wall...

 Two aspects of the existing minimum rule (MR) are used in the optimization of heat exchange networks (HENs). One aspect is to use the minimum of the algebraic quantities Ω1 and Ω2 or the minimum of cold and hot stream heat capacity flowrates of each heat exchanger (HEX) in HEN optimization. The other aspect is the dependency (or relationship) between the input and output temperature differentials of each HEX in HEN. As a consequence of the first aspect, the ...

 This paper presents a systematic methodology for the optimal design of geothermal systems. First, the different components of the system superstructure are separately modeled using flowsheeting software. The superstructure includes the different conversion technologies, the potential resources and the demand profiles in energy services. It covers a wide panel of conventional resources and technologies like deep and shallow aquifers, heat pumps, organic Rankine cycles for combined heat and ...

 Mordenite is a zeolite that has been used as a selective adsorbent and as a catalyst. Mordenite zeolite with crystal diameter 65 nm and crystal length 7 μm was successively synthesized in the absence of organic template by hydrothermal method at 180 °C for 5 days after stirring at high speed and aging in the synthesis mixture with the molar composition of 12Na2O:100SiO2:2Al2O3:500H2O. The produced samples were investigated using XRD, SEM, FT-IR, EDS, DTA/TG and B...

 This paper reports additive-free, reproducible, low-temperature solution-based process for the preparation of crystalline ZnO nanorods by homogeneous precipitation from zinc acetate. Also, ZnO nanorod structured dye sensitized solar cells using ruthenium dye (Z907) have been fabricated and characterized. The formation and growth of zinc oxide nanorods are successfully achieved. We analyzed three different synthesis method using solution phase, autoclave and microwave. The calcination effec...

 In this research, TiO2 nanoparticles were treated with hydrophobic 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (fluorosilane) in acidic, neutral and alkaline conditions. The treated nanoparticles were characterized using FTIR spectroscopy, thermal gravimetric analysis, X-ray photoelectron spectroscopy, transmission electron microscopy and X-ray diffraction spectroscopy. Reflectance spectra were obtained using UV–vis diffuse reflectance spectroscopy and band gap energy of the va...