نتایج جستجو برای: temperature and pressure effect
تعداد نتایج: 17236480 فیلتر نتایج به سال:
although there are studies on pragmatic assessment, to date, literature has been almost silent about native and non-native english raters’ criteria for the assessment of efl learners’ pragmatic performance. focusing on this topic, this study pursued four purposes. the first one was to find criteria for rating the speech acts of apology and refusal in l2 by native and non-native english teachers...
nanosized al2o3 powder is synthesized by thermal metal organic chemical vapor deposition (mocvd)combined withplasma. the effects of reaction temperature, pressure, al(ch3)3 (tma) concentration and reactant gases (co2 and o2) on the characteristics of the synthesized al2o3 powders are investigated. the experimental results demonstrate that very fineal2o3 powders with mean particle size of about ...
Abstract: During solidification and casting in metallic molds, the heat flow is controlled by the thermal resistance at the casting-mold interface. Thus heat transfer coefficient at the metal- mold interface has a predominant effect on the rate of heat transfer. In some processes such as low pressure and die-casting, the effect of pressure on molten metal will affect the rate of heat transfer a...
The aim of this work is to optimize the oxidation resistance of ZrB2-SiC-based composites with different additives. Effect of nine factors including SiC, Cf, MoSi2, HfB2 and ZrC contents, milling time of Cf (M.t) and SPS parameters such as temperature, time and pressure on oxidation resistance in four levels was investigated. Taguchi design was applied to explore effective parameters for ...
in this thesis, phosphorus ylides [phbppy], [no2bppy] and [brbppy] have been synthesized through the formation of phosphonium salt and dihydrogenation, followed by the reaction of pd(oac)2 and the orthopalladated dinuclear complexes [pd(?-cl)(phbppy)]2, [pd(?-cl)(no2bppy)]2 and [pd(?-cl)(brbppy)]2 have been produced. the reaction of dinuclear complexes and bidentate ligands [l = bipy (2,2-bipyr...
this study investigated the effect of prior knowledge on the listening comprehension performance of fl learners. twenty students, male and female, drawn from the two intact groups of the senior and junior english language and literature majors were chosen as the participants of this study . the two groups were then randomly assigned into the experimental and control group. the experimental gr...
this study was an attempt to investigate and compare the effect of lexical inferencing and concept mapping on developing vocabulary retention of iranian language learners. sixty homogeneous students from different intact classes who were being taught as intermediate learners in sokhan english institute participated in this study. they were in different classes. a teacher made test as a pre-test...
output characteristics of fuel cells are affected by a large number of parameters such as geometry, dimensions, construction materials and conditions of supplying fluids. in this paper a mathematical model followed by a two-dimensional numerical approach has been presented to study the fuel cell parametrically. effect of oxygen concentration at gas diffusion layer entrance, temperature and pres...
in this paper, a new combined power and refrigeration cycle is proposed, which combines the rankin power cycle and the ejector refrigeration cycle. this combined cycle produces both power output and refrigeration output simultaneously. this cycle is driven by the flue gas of gas turbines, industrial waste heats, solar energy and geothermal energy. an exergy analysis is performed to guide the th...
چکیده : * در یک واکنش تک ظرفی و با استفاده از واکنش آلدهید های آروماتیک و 3- متیل 1- فنیل پیرازولین-5- ان با نسبت مولی 1:1، ساختارهای هتروسیکل پیرازول سنتز شد. از مزایای آن، انجام واکنش در دمای اتاق، عدم نیاز به کاتالیزور، بازده بالای واکنش، استفاده از آب بعنوان حلال سبز و بی خطر به جای حلال های آلی وسمی می باشد . * توانستیم با استفاده از ملدرام اسید ومشتقات 2- هیدروکسی بنزآلدهید، ترکی...
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