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Combustion and emissions of the diesel engine using bio-diesel fuel

YUAN Yinnan, MEI Deqing, WANG Zhong, ZHANG Tian

《机械工程前沿（英文）》 2008年第3卷第2期页码 189-192 doi: 10.1007/s11465-008-0021-6

摘要： The combustion and heat release of engines using diesel fuel and bio-diesel fuel have been investigated. The results illustrate that the combustion happens in advance and the ignition delay period is shortened. The initial heat release peak declines a little, the corresponding crankshaft angle changes in advance, and the combustion duration is prolonged. The economic performance and emission features of diesel engines using diesel fuel and bio-diesel fuel are compared. The results also show that the specific fuel consumption of bio-diesel increases by about 12% .The emissions, such as CO, HC, and particulate matter decrease remarkably whereas NO increases a little.

关键词： advance combustion consumption economic performance combustion duration

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Combustion analysis of a hydrogen-diesel fuel operated DI diesel engine with exhaust gas recirculation

M. LOGANATHAN, A. VELMURUGAN, TOM PAGE, E. JAMES GUNASEKARAN, P. TAMILARASAN

《能源前沿（英文）》 2017年第11卷第4期页码 568-574 doi: 10.1007/s11708-017-0461-y

摘要： The rapid depletion of fossil fuel and growing demand necessitates researchers to find alternative fuels which are clean and sustainable. The need for finding renewable, low cost and environmentally friendly fuel resources can never be understated. An efficient method of generation and storage of hydrogen will enable automotive manufacturers to introduce hydrogen fuelled engine in the market. In this paper, a conventional DI diesel engine was modified to operate as gas engine. The intake manifold of the engine was supplied with hydrogen along with recirculated exhaust gas and air. The injection rates of hydrogen were maintained at three levels with 2 L/min, 4 L/min, 6 L/min and 8 L/min and 10 L/min with an injection pressure of 2 bar. Many of the combustion parameters like heat release rate (HRR), ignition delay, combustion duration, rate of pressure rise (ROPR), cumulative heat release rate (CHR), and cyclic pressure fluctuations were measured. The HRR peak pressure decreased with the increase in EGR rate, while combustion duration increased with the EGR rate. The cyclic pressure variation also increased with the increase in EGR rate.

关键词： hydrogen exhaust gas recirculation (EGR) diesel combustion heat release rate (HRR) combustion duration

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Construction Duration and Cost Simulation via Network-Program-Diagram

Wei-dong Wang,Jie Wu,Kai-jun Wang,Xin Wen

《工程管理前沿（英文）》 2014年第1卷第2期页码 210-217 doi: 10.15302/J-FEM-2014028

摘要： This paper outlines the creation of a simulation model used to extrapolate duration and resource requirements needed for the construction of bridges based on a sampling of data obtained during a field research conducted on the construction process of a single bridge. A sampling of statistical data was taken during a field investigation to measure schedule and resource requirements (labor, raw materials and machinery) at various stages of a bridge construction project. This data was used to identify the probability distribution and the associated parameters for the project examined, and a simulation model was built to extrapolate the necessary schedule and resource requirements needed for various stages of similar bridge projects based on Three-Point Estimation Method of Program Evaluation and Review Technique (PERT) and Monte Carlo Method. This simulation model’s resultant data for every process in an applicable construction project can be aggregated to form overall project duration and resource requirement statistical distribution using the Critical Path Method (CPM). The whole construction process will be visualized by a 4-dimensional (4D) model of the project which is created by appending time and resource requirements and to the 3-dimensional (3D) model that is built using the Building Information Modeling (BIM) and Alternativa 3D technology. Based on the simulation results of every procedure’s duration and resource requirements, the Network Program Diagram and Gantt Chart can be drawn with Flex and ActionScript language. Furthermore, with the Network Program Diagram at the core, the 4D model can incorporate simulation’s resultant data with respect to total time and cost of the project to show the condition of resource requirements and the project’s progressing at any time.

关键词： construction duration construction cost activity-on-node diagram building information modeling

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Effects of vitrification and cryostorage duration on single-cell RNA-Seq profiling of vitrified-thawed

Ying Huo, Peng Yuan, Qingyuan Qin, Zhiqiang Yan, Liying Yan, Ping Liu, Rong Li, Jie Yan, Jie Qiao

《医学前沿（英文）》 2021年第15卷第1期页码 144-154 doi: 10.1007/s11684-020-0792-7

摘要： Oocyte cryopreservation is widely used for clinical and social reasons. Previous studies have demonstrated that conventional slow-freezing cryopreservation procedures, but not storage time, can alter the gene expression profiles of frozen oocytes. Whether vitrification procedures and the related frozen storage durations have any effects on the transcriptomes of human metaphase II oocytes remain unknown. Four women (30–32 years old) who had undergone IVF treatment were recruited for this study. RNA-Seq profiles of 3 fresh oocytes and 13 surviving vitrified-thawed oocytes (3, 3, 4, and 3 oocytes were cryostored for 1, 2, 3, and 12 months) were analyzed at a single-cell resolution. A total of 1987 genes were differentially expressed in the 13 vitrified-thawed oocytes. However, no differentially expressed genes were found between any two groups among the 1-, 2-, 3-, and 12-month storage groups. Further analysis revealed that the aberrant genes in the vitrified oocytes were closely related to oogenesis and development. Our findings indicated that the effects of vitrification on the transcriptomes of mature human oocytes are induced by the procedure itself, suggesting that long-term cryostorage of human oocytes is safe.

关键词： human metaphase II oocyte vitrification cryostorage duration single-cell RNA-Seq lncRNA

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基于工期可控性的网络进度计划仿真评价方法研究

潘菲菲,王仁超,曹永雷

《中国工程科学》 2015年第17卷第1期页码 143-150

摘要：

针对工程建设过程中常常通过资源重新配置或提高资源利用率来应对风险事件可能引起工期延迟的问题，提出了基于工期可控性的网络进度计划随机仿真评价方法，以资源配置和利用裕度作为活动的可控性衡量指标，同时考虑了风险事件发生时间不同导致的风险应对措施的可实施性不同的问题，通过对各个风险事件发生时间及其引起的活动持续时间延误、风险应对效果等进行随机仿真，从而对整个项目的工期分布进行模拟，评价编制的网络进度计划的合理性。算例表明：相对于传统的基于工期和基于因素的Monte-Carlo仿真评价方法，基于工期可控性的仿真评价方法得到的结果更为合理。

关键词：网络进度计划；随机仿真；风险应对；工期可控性；评价

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项目进度管理中基于挣值的随机工期分析 Review

Fernando Acebes, David Poza, José Manuel González-Varona, Adolfo López-Paredes

《工程（英文）》 2022年第9卷第2期页码 148-162 doi: 10.1016/j.eng.2021.07.019

摘要：

挣值工期管理（EDM）是一种用于项目进度管理（PSM）的研究方法，当无法使用挣值管理（EVM）时，可以考虑这种方法。挣值工期管理用于估算进度偏差和最终项目工期。挣值工期管理和挣值管理的关键区别在于：在挣值工期管理中，用工作周期表示活动的值；而在挣值管理中，用成本表示活动的值。本文将展示如何使用挣值工期管理监控随机项目。为便于解释该方法，本文通过实例分析对呈现出高度不确定性的项目开展研究，项目中的各项活动采用随机工期。根据这些活动的网络拓扑分析该方法的可用性，并比较了挣值管理和挣值进度分析法（ESM）对项目进度管理的作用。

关键词：挣值工期管理挣值管理随机项目控制工期预测不确定性

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Combustion characteristics and kinetics of bio-oil

Ruixia ZHANG, Zhaoping ZHONG, Yaji HUANG

《化学科学与工程前沿（英文）》 2009年第3卷第2期页码 119-124 doi: 10.1007/s11705-009-0068-x

摘要： The combustion characteristics of bio-oils derived from rice husk and corn were studied by thermogravimetry analysis. According to the thermogravimetry (TG), differential thermogravimetry (DTG) and differential thermal analysis (DTA) curves of bio-oils in air and nitrogen atmosphere, we analyzed the combustion characteristics of different kinds of bio-oils in different atmospheres and worked out the combustion kinetics parameters of the bio-oil, providing reliable base data for the burning of bio-oil. The thermogravimetry indicated that the combustion process of bio-oil was divided into three stages. At the same time, the combustion process can be described by different order reaction models, and with the method of Coats-Redfern, the activation energy and frequency factor of different kinds of bio-oils were obtained.

关键词： bio-oil combustion characteristics combustion kinetics

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Numerical simulation of laminar premixed combustion in a porous burner

ZHAO Pinghui, CHEN Yiliang, LIU Minghou, DING Min, ZHANG Genxuan

《能源前沿（英文）》 2007年第1卷第2期页码 233-238 doi: 10.1007/s11708-007-0032-8

摘要： Premixed combustion in porous media differs substantially from combustion in free space. The interphase heat transfer between a gas mixture and a porous medium becomes dominant in the premixed combustion process. In this paper, the premixed combustion of CH

关键词： interphase mixture dominant Premixed combustion premixed combustion

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Entropy production analysis of swirling diffusion combustion processes

Deodat MAKHANLALL, Linhua LIU,

《能源前沿（英文）》 2010年第4卷第3期页码 326-332 doi: 10.1007/s11708-009-0058-1

摘要： A critical factor in the design of combustion systems for optimum fuel economy and emission performance lies in adequately predicting thermodynamic irreversibilities associated with transport and chemical processes. The objective of this study is to map these irreversibilities in terms of entropy production for methane combustion. The numerical solution of the combustion process is conducted with the help of a Fluent 6.1.22 computer code, and the volumetric entropy production rate due to chemical reaction, viscous dissipation, and mass and heat transfer are calculated as post-processed quantities with the computed data of the reaction rates, fluid velocity, temperature and radiative intensity. This paper shows that radiative heat transfer, which is an important source of entropy production, cannot be omitted for combustion systems. The study is extended by conducting a parametric investigation to include the effects of wall emissivity, optical thickness, swirl number, and Boltzmann number on entropy production. Global entropy production rates decrease with the increase in swirl velocity, wall emissivity and optical thickness. Introducing swirling air into the combustion system and operations with the appropriate Boltzmann number reduces the irreversibility affected regions and improves energy utilization efficiency.

关键词： entropy-based design radiation transfer swirl magnussen combustion-model

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Study on combustion characteristics of blended coals

LI Yonghua, WANG Chunbo, CHEN Hongwei

《能源前沿（英文）》 2007年第1卷第1期页码 96-100 doi: 10.1007/s11708-007-0010-1

摘要： Power plants in China have to burn blended coal instead of one specific coal for a variety of reasons. So it is of great necessity to investigate the combustion of blended coals. Using a test rig with a capacity of 640 MJ/h with an absolute milling system and flue gas online analysis system, characteristics such as burnout, slag, and pollution of some blended coals were investigated. The ratio of coke and slag as a method of distinguishing coal slagging characteristic was introduced. The results show that the blending of coal has some effect on NO but there is no obvious rule. SO emission can be reduced by blending low sulfur coal.

关键词： combustion capacity variety blended burnout

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Recent progress in electric-field assisted combustion: a brief review

《能源前沿（英文）》 2022年第16卷第6期页码 883-899 doi: 10.1007/s11708-021-0770-z

摘要： The control of combustion is a hot and classical topic. Among the combustion technologies, electric-field assisted combustion is an advanced techno-logy that enjoys major advantages such as fast response and low power consumption compared with thermal power. However, its fundamental principle and impacts on the flames are complicated due to the coupling between physics, chemistry, and electromagnetics. In the last two decades, tremendous efforts have been made to understand electric-field assisted combustion. New observations have been reported based on different combustion systems and improved diagnostics. The main impacts, including flame stabilization, emission reduction, and flame propagation, have been revealed by both simulative and experimental studies. These findings significantly facilitate the application of electric-field assisted combustion. This brief review is intended to provide a comprehensive overview of the recent progress of this combustion technology and further point out research opportunities worth investigation.

关键词： electric field combustion flame stabilization emission reduction flame propagation

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Catalytic combustion of volatile organic compounds using perovskite oxides catalysts—a review

《化学科学与工程前沿（英文）》 2023年第17卷第11期页码 1649-1676 doi: 10.1007/s11705-023-2324-x

摘要： With the rapid development of industry, volatile organic compounds (VOCs) are gaining attention as a class of pollutants that need to be eliminated due to their adverse effects on the environment and human health. Catalytic combustion is the most popular technology used for the removal of VOCs as it can be adapted to different organic emissions under mild conditions. This review first introduces the hazards of VOCs, their treatment technologies, and summarizes the treatment mechanism issues. Next, the characteristics and catalytic performance of perovskite oxides as catalysts for VOC removal are expounded, with a special focus on lattice distortions and surface defects caused by metal doping and surface modifications, and on the treatment of different VOCs. The challenges and the prospects regarding the design of perovskite oxides catalysts for the catalytic combustion of VOCs are also discussed. This review provides a reference base for improving the performance of perovskite catalysts to treat VOCs.

关键词： perovskite oxides volatile organic compounds catalytic combustion reaction mechanism

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Impact of oxygen enriched combustion on the performance of a single cylinder diesel engine

K. RAJKUMAR, P. GOVINDARAJAN

《能源前沿（英文）》 2011年第5卷第4期页码 398-403 doi: 10.1007/s11708-011-0157-7

摘要： In the present experiment, a computerized single cylinder diesel engine with a data acquisition system was used to study the effects of oxygen enriched combustion technology (OECT) on the performance characteristics. The use of different levels of oxygen-enriched air was compared with respect to percentage load. Increasing the oxygen content in the air leads to faster burn rates and increases the combustibility at the same stoichiometry (oxygen-to-fuel ratio). These effects have the potential to increase the thermal efficiency and specific power output of a diesel engine. The power increases considerably with oxygen enrichment. In addition, oxygen enrichment can also be considered as a way to reduce the sudden loss in power output when the engine operates in a high load condition. Assessed high combustion temperature from the oxygen enriched combustion leads to high combustion efficiency. OECT reduces the volume of flue gases and reduces the effects of greenhouse effects. Engine tests were conducted in the above said engine for different loads and the following performance characteristics like brake power (BP), specific fuel consumption (SFC), mean effective pressure, brake thermal efficiency, mechanical efficiency, and exhaust gas temperature were studied. The objective of this paper is to address, in a systematic way, the key technical issues associated with applying OECT to single cylinder diesel engines.

关键词： oxygen enriched combustion exhaust gas temperature brake power (BP) specific fuel consumption (SFC)

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Effect of Fe on NO release during char combustion in air and O

Ying GU, Xiaowei LIU, Bo ZHAO, Minghou XU

《能源前沿（英文）》 2012年第6卷第2期页码 200-206 doi: 10.1007/s11708-012-0181-2

摘要： The chemistry of char was probed by studying nitrogen release under the reactions with air and oxy-fuel combustion. The experiments were conducted in a drop tube furnace and a fixed bed flow reactor. NO was observed during those experiments. The results show that the particle size of char generated at 1073 K in CO is larger than that in N . However, at 1573 K, it is smaller in CO atmosphere due to particle breaking by gasification of char and CO . The Fe addition increases the NO conversion ratio, and the effect of Fe rises steeply with the process going until it becomes stable in the end. The results also indicate that the release of NO increases more significantly with the Fe addition in oxy-fuel environment.

关键词： NO Fe char combustion CO₂

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Influence of temperature on cam-tappet lubrication in an internal combustion engine

CHANG Qiuying, YANG Peiran, WANG Jing, CHEN Quanshi

《机械工程前沿（英文）》 2007年第2卷第4期页码 489-492 doi: 10.1007/s11465-007-0085-8

摘要： The transient thermo-elastohydrodynamic (TEHL) lubrication simulation and isothermal elastohydrodynamic (EHL) simulation were performed on the exhausting cam-tappet friction pair of an internal combustion engine. Although by employing the two models the center pressure, the thickness of the lubricant film and friction coefficient obtained were similar in the changing trend during a rotating cycle, the parameters make a great difference, especially for the thickness of the lubricant film; the TEHL was four times thicker than the EHL. These results show that the temperature should not be neglected in the study of the lubrication of cam-tappet pairs.

关键词： coefficient combustion isothermal elastohydrodynamic temperature thickness