This study presents comparative energy and exergy analyses of a four-cylinder, four-stroke spark-ignition engine using gasoline fuels of three different research octane numbers (RONs), namely 91, 93 and 95.3. Each fuel test was performed by varying the engine speed between 1200 and 2400 rpm while keeping the engine torque at 20 and 40Nm. Then, using the steady-state data along with energy and e...

The Army is developing hypergolic, liquid and gelled bipropellants for a small, selectable-thrust, liquid rocket engine (LRE) that can power tactical missiles for both current and future combat systems. The use of gel propellants brings the advantages of selectable thrust and the promise of small engine size but also introduces new challenges in combustion control. One of these challenges is th...

The objective of the present work is to evaluate whether variable ignition timing can be effect on exhaust emission and engine performance of a spark ignition engine. The study describes some results of research in the area of spark ignition engine and is assessed by studying its performance and emission characteristics relative to that of conventional ignition engine using gasoline and methano...

There are many algorithms for optimizing the search engine results, ranking takes place according to one or more parameters such as; Backward Links, Forward Links, Content, click through rate and etc. The quality and performance of these algorithms depend on the listed parameters. The ranking is one of the most important components of the search engine that represents the degree of the vitality...

Increasingly restrictive emission regulations and renewed focus on energy efficiency drive the current researches to find alternative fuels and their related better combustion strategies. In this regard, dual fuel engines, in which natural gas fuel is used as a main fuel and diesel fuel is employed as a pilot fuel, have received considerable attention. However, poor fuel utilization efficiencie...

Resource discovery in a distributed digital library poses many challenges, one of which is how to choose search engines for query distribution, given a query and a set of search engines. This paper focuses on search engine performance as a criterion for search engine selection and defines two measurements of search engine performance: availability – will the search engine respond within a time ...