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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    

火灾中闭式喷头响应特性研究

张村峰,霍然,李元洲

《中国工程科学》 2005年 第7卷 第11期   页码 55-59

摘要:

探讨了火灾时闭式喷头的响应时间和启动闭式喷头的临界火源功率,通过分析计算,给出了喷头启动时间与各种影响因素的拟合公式。结果表明:响应时间与安装高度、环境温度呈近似线性关系;火灾增长方式对响应时间的增长快慢产生影响;喷头的响应时间常数与响应时间则成指数关系。随着高度增加,喷头启动的临界火源功率不断增大,当喷头安装高度较高时,为早期有效的控制火灾,必须采用快速响应喷头。

关键词: 喷头     临界热释放速率     响应时间    

性能化防火设计中火灾场景设置初步研究

徐亮,张和平,杨昀,朱五八

《中国工程科学》 2004年 第6卷 第1期   页码 64-67

摘要:

火灾场景的设置是性能化设计的关键步骤,重点介绍了常用的火灾增长曲线设计方法,并且以高架仓库火灾设计为例,说明了如何灵活运用火灾设计方法。

关键词: 火灾场景设置     火灾增长曲线     热释放速率    

用锥形量热仪研究细水雾抑制熄灭PVC火

黄鑫,刘江虹,张永丰,秦俊

《中国工程科学》 2006年 第8卷 第12期   页码 102-106

摘要:

利用锥形量热仪和单流体细水雾系统研究了细水雾抑制PVC火的过程,并观察了重燃现象的发生,测量了实验中热释放速率及O2,CO2,CO和烟气的浓度变化,并对不同细水雾工作压力及不同热辐射流量下的结果进行了比较。由实验可知细水雾能快速扑灭PVC火,且压力越大灭火越迅速,但是在灭火后停止施加细水雾会发生重燃现象,且重燃发生的时间长短与作用在燃料表面的水量有关。

关键词: PVC火     细水雾     热释放速率     重燃    

油池火中细水雾强化火焰现象的研究

陆强,李钙,廖光煊,黄鑫,朱伟

《中国工程科学》 2006年 第8卷 第7期   页码 78-82

摘要:

细水雾与油池火相互作用之初往往会使燃烧剧烈,强化火焰。实验研究与理论分析表明,雾滴在可燃物表面蒸发是造成这种现象的主要原因。通过改变燃料种类、喷头雾特性参数等实验工况发现火焰强化程度主要决定于燃料的挥发性以及雾滴的直径、速度等参数。而在油盆中加水后燃料表面温度降低、火焰功率下降,火焰强化现象随着加水量的增加而逐渐弱化乃至消失,细水雾系统的灭火时间也明显缩短。

关键词: 细水雾     油池火     共沸     过压     热释放速率    

Experimental investigations of frost release by hydrophilic surfaces

Zhongliang LIU, Lingyan HUANG, Yujun GOU, Yaomin LIU

《能源前沿(英文)》 2010年 第4卷 第4期   页码 475-487 doi: 10.1007/s11708-010-0114-x

摘要: Frost formation occurs when water vapor in the surrounding air comes into contact with cold surfaces through heat and mass transfer. It is usually an undesirable phenomenon in most refrigeration and cryogenic systems. A few studies have shown that changing the surface energy, such as increasing the surface hydrophilicity or hydrophobicity, has significant effects on frost growth. In this paper, a kind of hydrophilic polymer paint is formulated to counteract frost deposition on cold surfaces. The coated surface can retard frost formation up to three hours under low plate temperatures (-15.3°C) and high air humidity (72%). To test the antifrosting performance of the hydrophilic paint under more practical conditions, it is applied to a fin-and-tube heat exchanger and a domestic refrigerator at a coating thickness of 30 μm. Comparisons of frost deposition, pressure drops, and outlet temperatures are made between uncoated and coated heat exchangers. Under conditions of high air temperature (2.2°C) and relative high air humidity (90%), the paint prolongs the defrosting interval from 80 to 137 min. Experimental observations also show that the coated hydrophilic fins are free of frost deposition during the entire course of the test and that the coating has no significant additional thermal resistance.

关键词: frost formation     hydrophilicity     heat and mass transfer     performance    

Experimental study of heat transfer coefficient with rectangular baffle fin of solar air heater

Foued CHABANE,Nesrine HATRAF,Noureddine MOUMMI

《能源前沿(英文)》 2014年 第8卷 第2期   页码 160-172 doi: 10.1007/s11708-014-0321-y

摘要: This paper presents an experimental analysis of a single pass solar air collector with, and without using baffle fin. The heat transfer coefficient between the absorber plate and air can be considerably increased by using artificial roughness on the bottom plate and under the absorber plate of a solar air heater duct. An experimental study has been conducted to investigate the effect of roughness and operating parameters on heat transfer. The investigation has covered the range of Reynolds number from 1259 to 2517 depending on types of the configuration of the solar collectors. Based on the experimental data, values of Nusselt number have been determined for different values of configurations and operating parameters. To determine the enhancement in heat transfer and increment in thermal efficiency, the values of Nusselt have been compared with those of smooth duct under similar flow conditions.

关键词: Nusselt number     flow rate     heat transfer     heat transfer coefficient     thermal efficiency     forced convection    

Fracture behavior of two non-symmetrical collinear cracks emanating from an elliptical hole in a piezoelectric material

Junhong GUO, Zixing LU

《机械工程前沿(英文)》 2011年 第6卷 第3期   页码 296-300 doi: 10.1007/s11465-011-0236-9

摘要:

Based on the Stroh-type formalism and the technique of conformal mapping, the problem of two non-symmetrical collinear cracks emanating from an elliptical hole in a piezoelectric solid is investigated under remotely uniform in-plane electric loading and anti-plane mechanical loading, which allowed us to take the electric field inside the hole and cracks into account. The analytical solutions of the field intensity factors and the energy release rate are presented in closed-form, which includes the extreme cases for an impermeable crack and a permeable crack. Numerical results are then presented to reveal the effects of geometrical parameters, crack permeability and combined mechanical and electric loadings on the energy release rate.

关键词: piezoelectric materials     elliptical hole     semi-permeable crack     energy release rate     analytic solution    

Design of nanocarriers for efficient cellular uptake and endosomal release of small molecule and nucleic

Vaibhav Mundra, Ram I. Mahato

《化学科学与工程前沿(英文)》 2014年 第8卷 第4期   页码 387-404 doi: 10.1007/s11705-014-1457-3

摘要: There are many challenges in developing efficient and target specific delivery systems of small molecule and nucleic acid drugs. Cell membrane presents one of the major barriers for the penetration of hydrophilic macromolecules across the plasma membrane. Nanocarriers have been designed to enhance their cellular uptake via endocytosis but following their cellular uptake, endosomal escape is the rate limiting step which restricts the value associated with the enhanced uptake by nanocarriers. Viruses are an excellent model for efficient cytosolic delivery by nanocarriers. Viruses exploit intracellular cues to release the genome to cytosol. In this review, we first discuss different endocytic uptake pathways and endosomal escape mechanisms. We then summarize the existing tools for studying the intracellular trafficking of nanocarriers. Finally, we highlight the important design elements of recent virus-based nanocarriers for efficient cellular uptake and endosomal escape.

关键词: nanocarrier     cellular uptake     endosomal release     nucleic acid drug    

Experimental study on performance of passive and active solar stills in Indian coastal climatic condition

R. LALITHA NARAYANA, V. RAMACHANDRA RAJU

《能源前沿(英文)》 2020年 第14卷 第1期   页码 105-113 doi: 10.1007/s11708-018-0536-4

摘要: This present work is aimed to examine the effect of mass flow rate on distillate output and performance of a solar still in active mode. Outdoor experiments were conducted at the coastal town, Kakinada (16° 93′N/83° 33′E), Andhra Pradesh, India. A solar still with a 30° of fixed cover inclination, 1m of effective basin area, and a flat-plate collector (FPC) with an effective area of 2 m were used. An attempt was also made earlier in passive mode to optimize the water depth for the same solar still for maximum yield and distillation efficiency. For the passive still, it is observed that the capacity of heat storage and heat drop are significant parameters that affect the still performance. For the selected still design, the study reveals that 0.04 m water depth is the optimum value for specific climatic conditions. In the active solar still, with the optimum water depth, different flow rates of 0.5, 1 and 1.5 L/min are considered through FPC. It is observed that both the mass flow rate and the variation of internal heat transfer coefficients with the mass flow rate have a significant effect on the yield and performance of the still. The experimental results show that the combination of 1.5 L/min mass flow rate and an optimum water depth of 0.04m leads to a maximum yield for the active solar still. The enhanced yield of the active solar still is 57.55%, compared with that of the passive solar still, due to increase in area of radiation collection and more heat absorption rate.

关键词: distillation efficiency     solar still     heat transfer coefficient     water depth     optimum and mass flow rate    

Semi-solid materials for controlled release drug formulation: current status and future prospects

Michelle TRAN,Chun WANG

《化学科学与工程前沿(英文)》 2014年 第8卷 第2期   页码 225-232 doi: 10.1007/s11705-014-1429-7

摘要: Semi-solid materials represent an important category of inactive ingredients (excipients) of pharmaceutical products. Here we review several common semi-solid polymers currently used in the controlled release formulations of many drugs. These polymers are selected based on their importance and broad scope of application in FDA-approved drug products and include several polysaccharides (cellulose, starch, chitosan, alginate) and carbomers, a group of mucoadhesive synthetic polymers. Glyceride-based polymers used in self-emulsifying drug delivery systems (SEDDS) will also be discussed for its importance in formulating poorly water-soluble drugs. Unique features and advantages of each type of semi-solid materials are discussed and examples of their use in oral delivery of drugs are provided. Finally, future prospects of developing new and better semi-solid excipients are discussed with the objective of facilitating clinical translation.

关键词: controlled release     drug delivery     semi-solids     polymer     excipient    

Study on the NOx release rule along the boiler during pulverized coal combustion

JIN Jing, ZHANG Zhongxiao, LI Ruiyang

《能源前沿(英文)》 2007年 第1卷 第1期   页码 91-95 doi: 10.1007/s11708-007-0009-7

摘要: Numerical simulation and experimental study on NO release along the boiler during pulverized coal combustion have been conducted. With the increase of temperature the NO emission increased and the peak value of NO release moved forward. But when the temperature increased to a certain degree, NO emission began to reduce. NO emission increased with the increase of nitrogen content of coal. The peak value of NO release moved backwards with the increase of coal rank. NO emission increased obviously with the increase of stoichiometric ratio. There existed a critical average diameter of the pulverized coal (). If "d, NO emission reduced with the decrease of pulverized coal size. If >, NO emission reduced with the increase of the pulverized coal size. The results showed that the simulation results are in agreement with the experimental results for concentration distribution of NO along the axis of the furnace.

Capacity estimation and preliminary strategy for reducing the release of dioxins in China

YU Gang, ZHANG Qing, HUANG Jun, CAI Zhenxiao, SUI Qian

《环境科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 13-17 doi: 10.1007/s11783-007-0002-8

摘要: As a party of the Stockholm Convention on Persistent Organic Pollutants, China must submit its national implementation plan (NIP) for this convention. The strategy and action plan for reducing the release of dioxins in China are the most important components of the NIP. Three problems are key points for developing such strategy and action plan what are the key sources for applying the best available technology/best environmental practice (BAT/BEP) to reduce the release of dioxins? How about the capacity for reducing the dioxins release from the key sources? Where are the areas of priority for applying BAT/BEP? This paper shows the efforts towards the solution of these problems. The list of key sources covering about half of the total dioxins release was determined considering four criteria. The capacity of key sources were estimated based on the difference between the emission factor corresponding to the actual situation in 2004 and that corresponding to the scenario that all key sources have been applied BAT/BEP to reduce the dioxins release. The priority analysis using the geographical information system (GIS) tool has revealed that eastern provinces should be of high priority in the future reduction activities of dioxins release in China.

关键词: GIS     difference     capacity     scenario     implementation    

Synthesis and characterization of biocompatible polyurethanes for controlled release of hydrophobic and

Juichen YANG,Hong CHEN,Yuan YUAN,Debanjan SARKAR,Jie ZHENG

《化学科学与工程前沿(英文)》 2014年 第8卷 第4期   页码 498-510 doi: 10.1007/s11705-014-1451-9

摘要: Design of biocompatible and biodegradable polymer systems for sustained and controlled release of bioactive agents is critical for numerous biomedical applications. Here, we designed, synthesized, and characterized four polyurethane carrier systems for controlled release of model drugs. These polyurethanes are biocompatible and biodegradable because they consist of biocompatible poly(ethylene glycol) or poly(caprolactone diol) as soft segment, linear aliphatic hexamethylene diisocyanate or symmetrical aliphatic cyclic dicyclohexylmethane-4,4′-diisocyanate as hard segment, and biodegradable urethane linkage. They were characterized with Fourier transform infrared spectroscopy, atomic force microscope, and differential scanning calorimetry, whereas their degradation behaviors were investigated in both phosphate buffered saline and enzymatic solutions. By tuning polyurethane segments, different release profiles of hydrophobic and hydrophilic drugs were obtained in the absence and presence of enzymes. Such difference in release profiles was attributed to a complex interplay among structure, hydrophobicity, and degradability of polyurethanes, the size and hydrophobicity of drugs, and drug-polymer interactions. Different drug-polyurethane combinations modulated the distribution and location of the drugs in polymer matrix, thus inducing different drug release mechanisms. Our results highlight an important role of segmental structure of the polyurethane as an engineering tool to control drug release.

关键词: phase structure     degradation     polyurethanes     controlled release     drug delivery    

functional supramolecular nanoparticles based on pillar[5]arene for controlled generation, storage and release

《化学科学与工程前沿(英文)》 2023年 第17卷 第3期   页码 307-313 doi: 10.1007/s11705-022-2216-5

摘要: The storage and controlled release of singlet oxygen (1O2) have attracted increasing attention due to the wide application and microsecond lifetime of 1O2 in water. Herein we provide an integrated nanoplatform consisting of a diphenylanthracene derivative, a water-soluble pillar[5]arene and a photosensitizer tetrakis(4-hydroxyphenyl)porphyrin (TPP), that may provide the controlled generation, storage and release of singlet oxygen. We design a new diphenylanthracene derivative with two trimethylammonium bromide groups on both ends that can be well recognized by the pillar[5]arene. The formed nanocarriers can be used to load TPP through their supramolecular self-assembly. The resulting nanoparticles show good water-solubility and uniform spherical morphology. After laser irradiation (660 nm), the nanoparticles exhibit excellent ability for the generation and storage of 1O2. When the irradiated nanoparticles are heated above 80 °C, 1O2 can be released from the system. Therefore, in this paper we pioneer the use of noncovalent interaction to integrate the diphenylanthracene derivatives and photosensitizers into one functional system, which provides a new strategy for the controlled generation, storage and release of singlet oxygen. We believe this groundbreaking strategy will have a great potential in providing necessary amounts of 1O2 for the photodynamic therapy of tumors in dark.

关键词: storage and controlled release of singlet oxygen     supramolecular nanoparticles     noncovalent interactions     pillararenes     diphenylanthracene     photosensitizers    

标题 作者 时间 类型 操作

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

期刊论文

火灾中闭式喷头响应特性研究

张村峰,霍然,李元洲

期刊论文

性能化防火设计中火灾场景设置初步研究

徐亮,张和平,杨昀,朱五八

期刊论文

用锥形量热仪研究细水雾抑制熄灭PVC火

黄鑫,刘江虹,张永丰,秦俊

期刊论文

油池火中细水雾强化火焰现象的研究

陆强,李钙,廖光煊,黄鑫,朱伟

期刊论文

Experimental investigations of frost release by hydrophilic surfaces

Zhongliang LIU, Lingyan HUANG, Yujun GOU, Yaomin LIU

期刊论文

Experimental study of heat transfer coefficient with rectangular baffle fin of solar air heater

Foued CHABANE,Nesrine HATRAF,Noureddine MOUMMI

期刊论文

Fracture behavior of two non-symmetrical collinear cracks emanating from an elliptical hole in a piezoelectric material

Junhong GUO, Zixing LU

期刊论文

Design of nanocarriers for efficient cellular uptake and endosomal release of small molecule and nucleic

Vaibhav Mundra, Ram I. Mahato

期刊论文

Experimental study on performance of passive and active solar stills in Indian coastal climatic condition

R. LALITHA NARAYANA, V. RAMACHANDRA RAJU

期刊论文

Semi-solid materials for controlled release drug formulation: current status and future prospects

Michelle TRAN,Chun WANG

期刊论文

Study on the NOx release rule along the boiler during pulverized coal combustion

JIN Jing, ZHANG Zhongxiao, LI Ruiyang

期刊论文

Capacity estimation and preliminary strategy for reducing the release of dioxins in China

YU Gang, ZHANG Qing, HUANG Jun, CAI Zhenxiao, SUI Qian

期刊论文

Synthesis and characterization of biocompatible polyurethanes for controlled release of hydrophobic and

Juichen YANG,Hong CHEN,Yuan YUAN,Debanjan SARKAR,Jie ZHENG

期刊论文

functional supramolecular nanoparticles based on pillar[5]arene for controlled generation, storage and release

期刊论文