Exhaust Emissions from an Engine Fueled with Biodiesel from High-Oleic Soybeans

Biodiesel is a fuel comprising mono-alkyl esters of medium to long-chain fatty acids derived from vegetable oils or animal fats. Typically, engines operated on soybean-based biodiesel exhibit higher emissions of oxides of nitrogen (NOx) compared with petroleum diesel. The increase in NOx emissions might be an inherent characteristic of soybean oil’s polyunsaturation, because the level of saturation is known to affect the biodiesel’s cetane number, which can affect NOx. A feedstock that is mostly monounsaturated (i.e. oleate) helps to balance the tradeoff between cold flow and oxidative stability. Genetic modification has produced a soybean event, designated 335-13, with a fatty acid profile high in oleic acid (>85%) and with reduced palmitic acid (<4%). This high-oleic soybean oil was converted to biodiesel and run in a John Deere 4045T 4.5-L four-stroke, four-cylinder, turbocharged direct-injection diesel engine. The exhaust emissions were compared with those from conventional soybean oil biodiesel and commercial No. 2 diesel fuel. There was a significant reduction in NOx emissions (α = 0.05) using the high-oleic soybean biodiesel compared with regular soybean oil biodiesel. No significant differences were found between the regular and high-oleic biodiesel for unburned hydrocarbon and smoke emissions.     

基于Nutch与元搜索引擎技术的高校网络舆情监测系统研究

针对高校网络舆情监测工作的不足,结合高校舆情信息的传播特点,提出了在校园网范围内基于Nutch搜索引擎技术进行信息检索,在互联网上采用元搜索引擎技术获取相关信息的舆情监测系统构建方案。采用关键词特征库匹配方式自动进行网络舆情监测,及时准确地发现网络舆情信息;探讨了高校对于网络舆情的监测、分析、引导和反馈等环节的处理方法,从而形成完善的应对机制。     

互联网应用发展和用户行为解析

互联网在我国迅猛发展,其应用不断创新发展。本文从搜索引擎、社交网站、电子商务、网络视频、网络游戏、移动互联网6个方面对互联网应用发展现状以及各种用户的行为习惯进行研究．最后分析了各种互联网应用的发展趋势。     

基于 HowNet 的用户兴趣挖掘研究及应用磁

搜索引擎中用户查询和网页资源之间的相似度研究一直是页面排序的研究核心。利用 HowNet 对词语的语义层次架构模型,对用户的检索词进行兴趣挖掘,同时对检索词和挖掘出的兴趣关键词的语义相似度计算方法进行改进,用户的检索请求与分块后的网页资源进行相似度迭代计算。实验结果表明,改进的算法使得页面排序的准确率和首页命中率有了较大提高。     

模糊逻辑在模拟演练系统智能体设计中的应用

根据模拟演练系统对智能体智能程度的要求为模拟演练系统添加模糊推理机,以增加演练系统的逼真程度及适应性. 本文以模糊逻辑理论为基础,以模拟演练系统为背景,对一个具体的应用实例进行数学建模,阐述了如何运用模糊逻辑来解决问题,并设计了模糊逻辑模块,通过应用实例演示验证了设计的可行性.     

文献搜索引擎中特征项及权重的应用

针对目前用户在使用搜索引擎过程中,检索结果冗余、效率低下等问题,本文在对文献垂直搜索系统中Lucene.Net的索引算法研究基础上,结合用户实际专业检索需求,改变其算法中的激励因子,实验结果证明该方法确能提高搜索结果的相关度.     

一种跨平台实时控制系统设备驱动的设计与实现

针对实时控制系统接入各种现场设备并与之通讯的问题,提出并设计了一种跨平台实时控制系统的现场设备驱动。首先概述了设计的基本原理,然后详细阐述了驱动函数,驱动模块,驱动引擎等各模块的设计及在多操作系统平台的实现。最后以实际的使用示例说明设备驱动的使用方法。     

Fuel properties and emissions of soybean oil esters as diesel fuel

The effects of using blends of methyl and isopropyl esters of soybean oil with No. 2 diesel fuel were studied at several steady-state operating conditions in a four-cylinder turbocharged diesel engine. Fuel blends that contained 20, 50, and 70% methyl soyate and 20 and 50% isopropyl soyate were tested. Fuel properties, such as cetane number, also were investigated. Both methyl and isopropyl esters provided significant reductions in particulate emissions compared with No. 2 diesel fuel. A blend of 50% methyl ester and 50% No. 2 diesel fuel provided a reduction of 37% in the carbon portion of the particulates and 25% in the total particulates. The 50% blend of isopropyl ester and 50% No. 2 diesel fuel gave a 55% reduction in carbon and a 28% reduction in total particulate emissions. Emissions of carbon monoxide and unburned hydrocarbons also were reduced significantly. Oxides of nitrogen increased by 12%.     

内网搜索引擎算法的分析与研究

近年来,Intranet不断飞速发展,导致信息量趋于庞大。于是如何让用户查找到自己想要的信息成为Intranet搜索引擎的一个难题。关于这个问题,它将对几种经典的Intranet搜索排序算法进行分析、比较。希望在以后的开发中可以以它为参照,进行相关算法的改进,尽可能的让算法更接近完美,使搜索结果更能符合用户的需求。     

基于OpenGL的图形引擎的设计与实现

近年过,随着图形硬件及图形接口的更新换代,用于游戏的实时图形引擎得到了突飞猛进的发展,各种开源引擎与商业引擎层出不穷。该文旨在运用计算机图形学理论知识,基于OpenGL 3.3的标准以及GLSL着色语言,使用C＋＋语言编写和Visual Studio 2010平台,完成一个拥有模型载入、贴图载入、UI界面、地形系统以及人机交互系统的图形引擎,能够用于游戏场景与漫游类的应用。