نتایج جستجو برای: lean burn
تعداد نتایج: 41655 فیلتر نتایج به سال:
Mesoporous noble metals are an emerging class of cutting-edge nanostructured catalysts due to their abundant exposed active sites and highly accessible surfaces. Although various noble metal (e.g. Pt, Pd and Au) structures have been synthesized by hard- and soft-templating methods, mesoporous rhodium (Rh) nanoparticles have never been generated via chemical reduction, in part due to the relativ...
Temperature compensating materials were investigated for a resistive oxygen sensor using Ce(0.9)Zr(0.1)O(2) as a sensor material for lean-burn engines. The temperature dependence of a temperature compensating material should be the same as the sensor material; therefore, the Y concentration in CeO(2)-Y(2)O(3) was optimized. The resistance of Ce(0.5)Y(0.5)O(2-δ) was independent of the air-to-fue...
The emission control of NOx in exhaust gases is one of the greatest engineering challenges to extend the practical and commercial application of diesel and lean burn engines. One solution is selective NOx reduction using hydrocarbons in an oxidizing atmosphere. We mainly focused on catalytic reactions under temperature excursion because of the resemblance to conditions prevailing in real automo...
Submodels are developed for injection, evaporation and wall impingement of a liquid LPG spray. The injection model determines the quality of fuel as two-phase choke flow at the nozzle exit. Wind tunnel experiments show the spray penetration more sensitive to ambient flow velocity than to injection pressure. Most evaporation occurs during choking, while heat transfer from surrounding air has a n...
Over the past twenty years catalysts containing platinum group metals have become the preferred means of limiting the polluting emissions of carbon monoxide, hydrocarbons and nitrogen oxides from motor vehicles. However, from time to time methods of exhaust control are proposed which appear to off.. a viable alternative to autocatalysts. Europe has been slow to adopt emission control standards ...
The propagation of detonations through several fuel-air mixtures with spatially varying fuel concentrations is examined numerically. The detonations propagate through two-dimensional channels, inside of which the gradient of mixture composition is oriented normal to the direction of propagation. The simulations are performed using a two-component, single-step reaction model calibrated so that o...
background : burn wounds are one of the health problems in modern societies that are associated with irreparable harms and many side problems for patients and their families. infection due to burn wounds is the main cause of death in such patients. one of the methods to prevent infection of burn wounds is topical antibiotic ointments. this study aimed to investigate and identify effective ointm...
Severe burns induce pathophysiologic problems, among them catabolism of lean mass, leading to protracted hospitalization and prolonged recovery. Oxandrolone is an anabolic agent shown to decrease lean mass catabolism and improve wound healing in the severely burned patients. We enrolled 81 adult subjects with burns 20% to 60% TBSA in a multicenter trial testing the effects of oxandrolone on len...
In this work, the effects of the electric fields on the flame propagation and combustion characteristics of lean premixed methane–air mixtures were experimentally investigated in a constant volume chamber. Results show that the flame front is remarkably stretched by the applied electric field, the stretched flame propagation velocity and the average flame propagation velocity are all accelerate...
background self-inflicted burn injuries carry considerable mortality and morbidity among otherwise fit young individuals. this study assessed the epidemiologic pattern and outcome of these injuries in a burn care facility in pakistan. methods the study was carried out at pakistan institute of medical sciences (pims) burn care centre in islamabad over a period of 2 years. it included all adult p...
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