检索结果-南通市图书馆

Control of peak pressures of an HCCI engine under varying swirl and operating parameters

Frontiers in Energy 2016年第3期10卷 337-346页

作者： T. KARTHIKEYA sharma g. AMBA PRASAd RAO K. MAdHU MURTHY department of Mechanical Engineering NIT Warangal Warangal506004 India

The major advantages of homogeneous charge compression ignition （HCCI） are high efficiency in combination with low NOx-emissions. However, one of the major challenges with HCCI is the control of higher peak pressures which may damage the engine, limiting the HCCI engine life period. In this paper, an attempt is made to analyze computationally the effect of induction swirl in controlling the peak pressures of an HCCI engine under various operating parameters. A single cylinder 1.6 L reentrant piston bowl diesel engine is chosen. For computational analysis, the ECFM-3Z model of STAR - Cd is considered because it is suitable for analyzing the combustion processes in SI and CI engines. As an HCCI engine is a hybrid version of SI and CI engines, the ECFM- 3Z model with necessary modifications is used to analyze the peak pressures inside the combustion chamber. The ECFM-3Z model for HCCI mode of combustion is validated with the existing literature to make sure that the results obtained are accurate. Numerical experiments are performed to study the effect of varying properties like speed of the engine, piston bowl geometry, exhaust gas recirculation （EgR） and equivalence ratio under different swirl ratios in controlling the peak pressures inside the combustion chamber. The results show that the swirl ratio has a considerable impact on controlling the peak pressures of HCCI engine. A reduction in peak pressures are observed with a swirl ratio of 4 because of reduced in cylinder temperatures. The combined effect of four operating parameters, i.e., the speed of the engine, piston bowl geometry, EgR, and equivalence ratio with swirl ratios suggest that lower intake temperatures, reentrant piston bowl, higher engine speeds and higher swirl ratios are favorable in controlling the peak pressures.

关键词： HCCI engine ECFM-3Z Swirl ratio peak pressures engine speed piston bowl geometry

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Assessment of land use change and its effect on soil carbon stock using multitemporal satellite data in semiarid region of Rajasthan, India

引用

Ecological Processes 2019年第1期8卷 513-529页

作者： garima sharma L.K.sharma K.C.sharma department of Environmental Science Central University of RajasthanNH-8BandarsindriRajasthan 305817India M.d.S.University AjmerRajasthanIndia.

Background:Land use change plays a vital role in global carbon *** land use change impact on soil carbon stock is crucial for implementing land use management to increase carbon stock and reducing carbon ***,the objective of our study was to determine land use change and to assess its effect on soil carbon stock in semi-arid part of Rajasthan,*** temporal satellite data of Pushkar valley region of Rajasthan acquired on 1993,2003,and 2014 were analyzed to assess land use *** trading of land use was depicted *** organic carbon(SOC)stock was calculated for soil to a depth of 30 cm in each land use type in 2014 using field data *** SOC stock for previous years was estimated using stock change *** effect of land use change on SOC stock was determined by calculating change in SOC stock(t/ha)by deducting the base-year SOC stock from the final year stock of a particular land use ***:The total area under agricultural lands was increased by 32.14%while that under forest was decreased by 23.14%during the time period of 1993–*** land use change shows that in both the periods(1993–2003 and 2003–2014),7%of forest area was converted to agricultural land and about 15%changes occurred among agricultural *** 1993–2003,changes among agricultural land led to maximum loss of soil carbon,i.e.,4.88 Mt C and during 2003–2014,conversion of forest to agricultural land led to loss in 3.16 Mt ***:There was a continuous decrease in forest area and increase in cultivated area in each time *** use change led to alteration in carbon equity in soil due to change or loss in ***,we can conclude that the internal trading of land use area during the 10-year period(1993–2003)led to net loss of SOC stock by 8.29 Mt ***,land use change during 11-year period(2003–2014)caused net loss of SOC by 2.76 Mt *** should be made to implement proper land

关键词： Multitemporal satellite data Land use change dynamics Internal trading of land use SOC stock,Stock change factor Change in SOC pool Land use management

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Remote sensing and census based assessment and scope for improvement of rice and wheat water productivity in the Indo-gangetic Basin

引用

Science China(Technological Sciences) 2009年第11期52卷 3300-3308页

作者： sharma Bharat International Water Management Institute (IWMI) New Delhi Office NASC Complex CG Block Dev Prakash Shastri Marg Pusa New Delhi 110012 India

Understanding of crop water productivity (WP) over large scale, e.g., river basin, has significant impli-cations for sustainable basin development planning. This paper presents a simplified approach to combine remote sensing, census and weather data to analyze basin rice and wheat WP in Indo-gangetic River Basin, South Asia. A crop dominance map is synthesized from ground truth data and three existing LULC maps. National statistics on crop area and production information are collected and the yield is interpolated to pixel level using moderate resolution imaging spectroradiometer (MOdIS) normalized difference vegetation index (NdVI). Crop evapotranspiration is mapped using simplified surface energy balance (SSEB) model with MOdIS land surface temperature products and meteorological data collected from 56 weather stations. The average ET by rice and wheat is 368 mm and 210 mm respectively, accounting for only 69% and 65% of potential ET, and 67% and 338% of rainfall of the crop growth period measured from Tropical Rainfall Measurement Mission (TRMM). Average WP for rice and wheat is 0.84 and 1.36 kg/m3 respectively. WP variability generally follows the same trend as shown by crop yield disregarding climate and topography changes. Sum of rice-wheat water productivity, however, exhibits different variability leading to better understanding of irrigation water management as wheat heavily relies on irrigation. Causes for variations and scope for improvement are also analyzed.

关键词： crop water productivity remote sensing census Indo-gangetic Basin

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Performance analysis of Sige double-gate N-MOSFET

引用

Journal of Semiconductors 2017年第4期38卷 38-44页

作者： A.Singh d.Kapoor R.sharma department of Electronics and Communication Engineering Vaish College of EngineeringRohtak 124001India department of Electronics and Communication Engineering Northern India Engineering CollegeNew Delhi 110053India

The major purpose of this paper is to find an alternative configuration that not only minimizes the limitations of single-gate（Sg） MOSFETs but also provides the better replacement for future *** this paper,the electrical characteristics of Sige double-gate N-MOSFET are demonstrated and compared with electrical characteristics of Si double-gate ***,in this paper the electrical characteristics of Si doublegate N-MOSFET are demonstrated and compared with electrical characteristics of Si single-gate *** simulations are carried out for the device at different operational voltages using Cogenda Visual TCAd ***,we have designed its structure and studied both Id-Vg characteristics for different voltages namely 0.05,0.1,0.5,0.8,1 and 1.5 V and Id-Vd characteristics for different voltages namely 0.1,0.5,1 and 1.5 V at work functions 4.5,4.6 and 4.8 eV for this *** performance parameters investigated in this paper are threshold voltage,dIBL,subthreshold slope,gIdL,volume inversion and MMCR.

关键词： double gate MOSFET dIBL gIdL volume inversion Sige genius tool

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Modeling the triaxial behavior of riverbed and blasted quarried rockfill materials using hardening soil model

引用

Journal of Rock Mechanics and geotechnical Engineering 2016年第3期8卷 350-365页

作者： N.P.Honkanadavar K.g.sharma Central Soil and Materials Research Station (CSMRS) New Delhi India Indian Institute of Technology delhi (IITd) New Delhi India

Riverbed modeled rockfill material from Noa dehing dam project, Arunachal Pradesh, India and blasted quarried modeled rockfill material from Kol dam project, Himachal Pradesh, India were considered for this research. Riverbed rockfill material is rounded to sub-rounded and quarried rockfill material is angular to sub-angular in shape. Prototype rockfill materials were modeled into maximum particle size （dmax） of 4.75 mm, 10 mm, 19 mm, 25 mm, 5O mm and 80 mm for testing in the laboratory. Consolidated drained triaxial tests were conducted on modeled rockfill materials with a specimen size of 381 mm in diameter and 813 mm in height to study the stress-strain-volume change behavior for both rockfill materials. Index properties, i.e. uncompacted void content （UVC） and uniaxial compressive strength （UCS）, were determined for both rockfill materials in association with material parameters. An elasto- plastic hardening soil （HS） constitutive model was used to predict the behavior of modeled rockfill materials. Comparing the predicted and observed stress-strain-volume change behavior, it is found that both observed and predicted behaviors match closely. The procedures were developed to predict the shear strength and elastic parameters of rockfill materials using the index properties, i.e. UCS, UVC and relative density （Rd）, and predictions were made satisfactorily. Comparing the predicted and experi- mentally determined shear strengths and elastic parameters, it is observed that both values match closely. Then these procedures were used to predict the elastic and shear strength parameters of large- size prototype rockfill materials. Correlations were also developed between index properties and ma- terial strength parameters （dilatancy angle, ~, and initial void ratio, einit, required for HS model） of modeled rockfill materials and the same correlations were used to predict the strength parameters for the prototype rockfill materials. Using the predicted material parameters,

关键词： Riverbed rockfill materialsQuarried rockfill materialsTriaxial testingModelingStrength lawHardening soil (HS) model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Synthesis of N1-3-{（4-Substituted aryl-3-chloro-2-oxo- azetidine）-iminocarbamyl}-propyl-6-nitroindazole derivatives and Their Biological Significance

引用

Chinese Journal of Chemistry 2011年第8期29卷 1745-1752页

作者： Samadhiya, Pushkal sharma, Ritu Srivastava, Santosh K. Srivastava, Savitri d. Synthetic Organic Chemistry Laboratory Department of Chemistry Dr. H. S. Gour University (A Central Univer- sity) Sagar M.P. 470003 India

Synthesis of N1-3-{（4-substitute daryl-3-chloro-2-oxo-azetidine）-iminocarbamyl}-propyl-6-nitroindazole 4a-- 4s was conducted by a conventional method. All the compounds were synthesized and characterized by IR, 1H NMR, 13C NMR, FAB-Mass techniques and chemical methods. All the final synthesized compounds were evaluated for their antimicrobial activity and antitubercular activity with MIC values against some selected microorganisms.

关键词： synthesis 6-nitroindazole 2-azetidinone biological activity

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

3d biofabrication of vascular networks for tissue regeneration:A report on recent advances

引用

Journal of Pharmaceutical Analysis 2018年第5期8卷 277-296页

作者： M.d.Sarker Saman Naghieh N.K.sharma Xiongbiao Chen division of Biomedical Engineering College of Engineering University of Saskatchewan department of Mechanical Engineering College of Engineering University of Saskatchewan

Rapid progress in tissue engineering research in past decades has opened up vast possibilities to tackle the challenges of generating tissues or organs that mimic native structures. The success of tissue engineered constructs largely depends on the incorporation of a stable vascular network that eventually anastomoses with the host vasculature to support the various biological functions of embedded cells. In recent years, significant progress has been achieved with respect to extrusion, laser, micro-molding, and electrospinning-based techniques that allow the fabrication of any geometry in a layer-by-layer fashion. Moreover, decellularized matrix, self-assembled structures, and cell sheets have been explored to replace the biopolymers needed for scaffold fabrication. While the techniques have evolved to create specific tissues or organs with outstanding geometric precision, formation of interconnected, functional, and perfused vascular networks remains a challenge. This article briefly reviews recent progress in 3d fabrication approaches used to fabricate vascular networks with incorporated cells, angiogenic factors, proteins, and/or peptides. The influence of the fabricated network on blood vessel formation, and the various features, merits, and shortcomings of the various fabrication techniques are discussed and summarized.

关键词： 3d bioprinting Tissue engineering Vascularization Extrusion Laser-based printing Co-axial printing

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Synthesis and Biological Study of Some 4-oxo-Thiazolidine derivatives of 2-Aminothiazole

引用

Chinese Journal of Chemistry 2011年第5期29卷 1001-1010页

作者： Samadhiya Pushkal sharma Ritu Srivastava Santosh K. Srivastava Savitri d. Synthetic Organic Chemistry Laboratory Department of Chemistry Dr. H.S. Gour University (A Central University) Sagar M.P. 470003 India

Conventional and microwave assisted synthesis of new series of N-[2-{2-（substituted phenyl）-4-oxo- 5-（substituted benzylidene）-1,3-thiazolidine}-iminoethyl]-2-aminothiazole 5a-Sin have been developed. The cycloaddition reaction of thioglycolic acid with N-{2-（substituted benzylidenehydrazino）-ethyl}-2-aminothiazole 3a--3m in the presence of anhydrous ZnC12 afforded new heterocyclic compounds N-[2-{2-（substituted phenyl）- 4-oxo-l,3-thiazolidine}-iminoethyl]-2-aminothiazole 4a---4m. The later product on treatment with several selected substituted aromatic aldehydes in the presence of C2HsONa undergoes Knoevenagel reaction to yield 5a--Sin. The structures of compounds 1, 2, 3a--3m, 4a---4m and 5a--Sm were confirmed by IR, IH NMR, 13C NMR, FAB-Mass and chemical analysis. All above compounds were screened for their antimicrobial activities against some selected bacteria and fungi and antituberculosis study against M. tuberculosis.

关键词： conventional microwave synthesis 2-aminothiazole 4-oxo-thiazolidine antimicrobial antitubercular

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Influence of Accompanying Anions on Potassium Retention and Leaching in Potato growing Alluvial Soils

引用

Pedosphere 2013年第4期23卷 464-471页

作者： V.sharma K.N.sharma department of Soils Punjab Agricultural University

A column study was carried out to assess the influence of accompanying anions on potassium （K） leaching at potato growing sites with different soil textures （sandy loam and clay loam） in northwestern India. Potassium was applied in the top 15 cm layer of soil column at 30 and 60 mg K kg-1 through different sources having different accompanying anions （CI-, SO^-, NO3 and H2PO4-）. Maximum K was retained in the top 0-15 cm layer with a sharp decrease in K content occurring in 15 30 cm layer of the soil column. The trend was similar for both levels of applied K as well as frequency of leaching and soil type. The decrease of K content in soil column after four leaching events was maximum in case of Khanaura sandy loam, while only minor decrease was observed in Hundowal clay loam when K was applied at 60 mg K kg-1, indicating higher potential of clay rich soil to adsorb K. In general, the K leaching in presence of the accompanying anions followed the order of SO4^2-≤ H2PO42- 〈 NO3 = Cl-. Highest 1 mol·L^-1 CH3COONH4-extractable K was retained when K was applied along with SO4^2- and H2PO4 anions, and the least was retained when accompanying anion was Cl-. The influence of anions was more pronounced in the light textured soil and at high amounts of K application. Higher levels of K application resulted in higher losses of K, especially in sandy loam soil as observed from the leachate concentration. Among the different K sources, the maximum amount of K leaching was noticed in the soil column amended with KC1. After four leachings, the maximum amount of K leached out was 6.40 mg L-1 in Hundowal clay loam and 9.29 mg L-1 in Khanaura sandy loam at 60 mg K kg-1 of soil application through KC1. These concentrations were lower than the recommended guideline of the World Health Organisation （12.00 mg L-1）.

关键词： column study leaching events potassium application potassium sources soil texture

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

data-driven Bayesian inference of turbulence model closure coefficients incorporating epistemic uncertainty

引用

Acta Mechanica Sinica 2021年第12期37卷 1812-1838页

作者： daigo Maruyama Philipp Bekemeyer Stefan gortz Simon Coggon Sanjiv sharma german Aerospace Center(dLR) Institute of Aerodynamics and Flow Technology Lilienthalplatz 738108 BraunschweigGermany Airbus Operations Limited Pegasus House Aerospace AveFiltonBristol BS347PA

We introduce a framework for statistical inference of the closure coefficients using machine learning *** objective of this framework is to quantify the epistemic uncertainty associated with the closure model by using experimental data via Bayesian *** framework is tailored towards cases for which a limited amount of experimental data is *** consists of two ***,by treating all latent variables(non-observed variables)in the model as stochastic variables,all sources of uncertainty of the probabilistic closure model are quantified by a fully Bayesian *** probabilistic model is defined to consist of the closure coefficients as parameters and other parameters incorporating ***,the uncertainty associated with the closure coefficients is extracted from the overall uncertainty by considering the noise being *** overall uncertainty is rigorously evaluated by using Markov-Chain Monte Carlo sampling assisted by surrogate *** apply the framework to the Spalart-Allmars one-equation turbulence *** test cases are considered,including an industrially relevant full aircraft model at transonic flow conditions,the Airbus ***,we demonstrate that epistemic uncertainties in the closure coefficients result into uncertainties in flow quantities of interest which are prominent around,and downstream,of the shock occurring over the XRF1 *** data-driven approach could help to enhance the predictive capabilities of CFd in terms of reliable turbulence modeling at extremes of the flight envelope if measured data is available,which is important in the context of robust design and towards virtual aircraft *** plentiful amount of information about the uncertainties could also assist when it comes to estimating the influence of the measured data on the inferred model ***,the developed framework is flexible and can be applied to different test cases and to various turbulence model

关键词： Turbulence modeling Uncertainty quantification Parameter calibration Bayesian statistics Surrogate-assisted methods Spalart-Allmaras one-equation turbulence model Large-scale industrial aircraft use-case

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：