检索结果-南通市图书馆

Numerical investigation on the aerodynamic drag reduction based on bottom deflectors and streamlined bogies of a high-speed train

引用

Journal of Central South University 2024年第9期31卷 3312-3328页

作者： JIANG Chen LONG jn-lan LI Yan-ong GAO Guang-jun franklin eze State Key Laboratory of Heavy-duty and Express High-power Electric Locomotive Central South UniversityChangsha 410075China Key Laboratory of Traffic Safety on Track of Ministry of Education School of Traffic&Transportation EngineeringCentral South UniversityChangsha 410075China National&Local Joint Engineering Research Center of Safety Technology for Rail Vehicle Central South UniversityChangsha 410075China Key Laboratory of Railway Industry of Aerodynamics Central South UniversityChangsha 410075China

The complex structure of the bottom of a high-speed train is an important source of train aerodynamic ***,improving the bottom structure is of great significance to reduce the aerodynamic drag of the *** this study,computational fluid dynamics(CFD)based on three-dimensional steady incompressible Reynolds-average Naiver-Stokes(RANS)equations and Realizable k-ε turbulence model were utilized for numerical *** by the concept of streamlined design and the idea of bottom flow field control,this study iteratively designed the bogies in a streamlined shape and combined them with the bottom deflectors to investigate the joint drag reduction *** models,i.e.,single-bogie model,simplified train model,and eight-car high-speed train model,were created and their aerodynamic characteristics were *** results show that the single-bogie model with streamlined design shows a noticeable drag reduction,whose power bogie and trailer bogie experience 13.92%and 7.63%drag reduction,*** range of positive pressure area on the bogie is *** aerodynamic drag can be further reduced to 15.01%by installing both the streamlined bogie and the deflector on the simplified train *** the streamlined bogies and deflectors are used on the eight-car model together,the total drag reduction rate reaches 2.90%.Therefore,the proposed aerodynamic kit for the high-speed train bottom is capable to improve the flow structure around the bogie regions,reduce the bottom flow velocity,and narrow the scope of the train’s influence on the surrounding environment,achieving the appreciable reduction of aerodynamic *** paper can provide a new idea for the drag reduction of high-speed trains.

关键词： high-speed train numerical simulation drag reduction deflector streamlined design

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

高速列车底部导流板与流线型转向架的综合减阻研究（英文）

引用

Journal of Central South University 2024年第9期 3312-3328页

作者：姜琛龙金兰李岩松高广军 franklin eze State Key Laboratory of Heavy-duty and Express High-power Electric Locomotive Central South University Key Laboratory of Traffic Safety on Track of Ministry of Education School of Traffic &Transportation Engineering Central South University National & Local Joint Engineering Research Center of Safety Technology for Rail Vehicle Central South University Key Laboratory of Railway Industry of Aerodynamics Central South University

高速列车底部结构复杂，是列车气动阻力的重要来源。因此，改善列车底部结构对减小列车气动阻力有重要意义。本文使用了三维稳定不可压缩雷诺平均N-S方程和Realizable k-ε湍流模型进行数值仿真研究。受流线设计理念和底部流场控制思想... 详细信息

高速列车底部结构复杂，是列车气动阻力的重要来源。因此，改善列车底部结构对减小列车气动阻力有重要意义。本文使用了三维稳定不可压缩雷诺平均N-S方程和Realizable k-ε湍流模型进行数值仿真研究。受流线设计理念和底部流场控制思想的启发，本文对高速列车转向架进行了流线型迭代设计，并结合底部导流板装置，分别对单转向架模型、简化车体模型和八编组高速列车模型进行气动特性分析，探究流线型转向架和导流板的综合减阻机理。结果表明：经过流线型设计的转向架气动阻力显著降低，单动车转向架和单拖车转向架的减阻率分别达到13.92%和7.63%，转向架上正压范围缩小。在简化车体上同时安装流线转向架与导流板，其气动阻力可以进一步减少到15.01%。当流线型转向架和导流板在八车编组模型上组合使用时，虽然会造成车体上的阻力系数增加，但转向架区域的阻力系数显著降低，转向架舱内空气流速减缓，同时列车滑流的影响范围缩小，流场结构显著改善，八车模型的减阻率达到2.90%。本文为高速列车的减阻设计提供了新思路。

关键词：高速列车数值仿真减阻导流板流线型转向架

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Advances in Vehicular Ad-hoc Networks(VANETs):Challenges and Road-map for Future Development

引用

International Journal of Automation and computing 2016年第1期13卷 1-18页

作者： Elias C.eze Si-Jing Zhang En-Jie Liu Joy C.eze Centre for Wireless Research Institute for Research in Applicable Computing (IRAC) Department of Computer Science and TechnologyUniversity of Bedfordshire

Recent advances in wireless communication technologies and auto-mobile industry have triggered a significant research interest in the field of vehicular ad-hoc networks （VANETs） over the past few years. A vehicular network consists of vehicle-to-vehicle （V2V） and vehicle-to-infrastructure （V2I） communications supported by wireless access technologies such as IEEE 802.11p. This innovation in wireless communication has been envisaged to improve road safety and motor traffic efficiency in near future through the development of intelligent transportation system （ITS）. Hence, governments, auto-mobile industries and academia are heavily partnering through several ongoing research projects to establish standards for VANETs. The typical set of VANET application areas, such as vehicle collision warning and traffic information dissemination have made VANET an interesting field of mobile wireless communication. This paper provides an overview on current research state, challenges, potentials of VANETs as well as the ways forward to achieving the long awaited ITS.

关键词： Vehicle-to-vehicle communication (V2V) vehicle-to-infrastructure (V2I) intelligent transport systems (ITS) IEEE802.11p wireless access in vehicular environment (WAVE) IEEE 1609.

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

Exploring factors of disaster preparedness in UNESCO-designated heritage sites

引用

Geography and Sustainability 2024年第3期5卷 392-404页

作者： Emmanuel eze Alexander Siegmund Institute of Geography&Heidelberg Center for the Environment(HCE) University of HeidelbergHeidelbergGermany Department of Geography-Research Group for Earth Observation(r geo) UNESCO Chair on Observation and Education of World Heritage&Biosphere ReserveHeidelberg University of EducationHeidelbergGermany Geographical and Environmental Education Unit Department of Social Science EducationUniversity of NigeriaNsukkaNigeria

Increased hazards threatening the United Nations Educational,Scientific and Cultural Organization(UNESCO)-designated sites and endangering cultural heritage and community well-being require attention and ***-sidering the pivotal role of UNESCO sites in conservation and development,this study assessed their levels of disaster *** absence of studies assessing disaster awareness,risk perception,and preparedness among UNESCO site actors,as well as the pivotal place of preparedness within the Disaster Risk Management(DRM)cycle justifies this *** the tenets of the Person-Relative-to-Event framework,we hypothe-sized that a strong positive correlation exists between perceived risks,resources,and disaster *** collect pertinent data,we employed an embedded mixed-method design and conducted an online questionnaire survey yielding 141 responses from 59 *** the results of relevant analyses,wildfires,floods,and droughts are top hazards occurring frequently in UNESCO sites,with significant concerns about pollution and habitat loss during future *** emerged as the most available crucial DRM resource,with higher availability of DRM resources correlating positively and significantly with sites’*** findings con-tribute valuable insights to address missing links for disaster-ready and resilient UNESCO sites,promoting their preservation for future generations.

关键词： Biosphere reserves Disaster risk management(DRM) Global geoparks Person-relative-to-event(PRE)framework Sustainability World heritage sites

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

Modulated Collective Motions and Condensation of Bacteria

引用

Chinese Physics Letters 2022年第10期39卷 79-84页

作者： Mei-Mei Bao Isaiah eze Igwe Kang Chen Tian-Hui Zhang Center for Soft Condensed Matter Physics and Interdisciplinary Research&School of Physical Science and Technology Soochow UniversitySuzhou 215006China Department of Physics Federal University Dutsin-MaKatsina State 821101Nigeria

Bacteria can spontaneously develop collective motions by aligning their motions in dense *** we show that bacteria can also respond collectively to an alternating electrical field and form dynamic clusters oscillating at the same frequency of the *** the dynamic clusters go beyond a critical size,they split into smaller ones *** critical size for splitting depends on the frequency of electric field and the concentration of *** show that,instead of their biological activity,the physical properties of bacteria as charged particles are responsible for the formation of dynamic *** flows across the system play the key role in stabilizing the ***,to form clusters,collective hydrodynamic cooperation between bacteria is important such that no aggregation occurs in dilute *** findings in this study illustrate that bio-systems can respond collectively to an external field,promising an effective way to control and modulate the behavior of ***,the controlled aggregation and condensation of bacteria offer a robust approach to improve the local concentration of bacteria for early and rapid detection,which has wide applications in clinics.

关键词： field collective aggregation

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

Prevalence of parasitemia and associated immunodeficiency among HIV—malaria co—infected adult patients with highly active antiretroviral therapy

引用

Asian Pacific Journal of Tropical Medicine 2013年第2期6卷 148-152页

作者： Caroline Edijana Omoti Chiedozie K.Ojide Patrick V.Lofor Emeka eze Joy C eze Department of Haematology and Blood Transfusion University of Benin Teaching HospitalBenin CityNigeria Department of Medical Microbiology University of Benin Teaching HospitalBenin CityNigeria Department of Internal Medicine University of Benin Teaching HospitalBenin CityNigeria

Objective:To investigate the malaria parasitemia,CD4~+ cell counts and some haematological indices among HIV-malaria co-infected adult patients with highly active antiretroviral therapy (HAART).Methods:A total of 342 adult HIV positive subjects were recruited at the consultant outpatient HIV/AIDS *** of Benin Teaching Hospital,Benin City,Nigeria between June 2011 to November *** samples were taken for malaria parasite count,CD4~+ cell count and other haematological ***:Out of the 342 adult HIV positive subjects a total of 254 patients(74.3%) were found to have malaria *** incidence of malaria parasitemia increased with advancing clinical stage of HIV infection and this was statistically significant(P=0.002).There was no statistical significance when gender was compared with the HIV-malaria status(P>0.05).Of the 254 co-infected patients,134(52.8%) had high parasitemia (>1.25×10~9/L).Sixty patients were found to be hyperparasitemic(>2.5 parasites/L).There was a significant association between CD4~+ cell count and having significant parasitemia(P0.05).Conclusions:The prevalence of parasitemia is high among the HIV/AIDS infected patients.

关键词： HIV Malaria HAART CD4~+

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

Kinetics and mechanistic investigation of epoxide/CO2 cycloaddition by a synergistic catalytic effect of pyrrolidinopyridinium iodide and zinc halides

引用

Journal of Energy Chemistry 2019年第10期28卷 35-42页

作者： Abdul Rehman Valentine C. eze M.F.M.Gunam Resul Adam Harvey School of Engineering Merz CourtNewcastle UniversityNewcastle Upon Tyne NE1 7RUUK Department of Chemical and Polymer Engineering University of Engineering and Technology LahoreFaisalabad CampusPakistan

Formation of styrene carbonate (SC) by the cycloaddition of CO2 to styrene oxide (SO) catalysed by pyrrolidinopyridinium iodide (PPI) in combination with zinc halides (ZnCl2, ZnBr2 and ZnI2) was investigated. Complete conversion of the SO to SC was achieved in 3 h with 100% selectivity using 1/0.5 molar (PPI/ZnI2) catalyst ratio under mild reaction conditions i.e., 100℃ and 10 bar CO2 pressure. The synergistic effect of ZnI2 and PPI resulted in more than 7-fold increase in reaction rate than using PPI alone. The cycloaddition reaction demonstrated the first-order dependence with respect to the epoxide, CO2 and catalyst concentrations. Moreover, the kinetic and thermodynamic activation parameters of SC formation were determined using the Arrhenius and Eyring equations. The positive values of △H(42.8 kJ mol^-1) and △G(102.3 kJ mol^-1) revealed endergonic and chemically controlled nature of the reaction, whereas the large negative values of △S(-159.4 J mol^-1 K^-1) indicate a highly ordered activated complex at the transition state. The activation energy for SC formation catalyzed by PPI alone was found to be 73.2 kJ mol^-1 over a temperature range of 100-140℃, which was reduced to 46.1 kJ mol^-1 when using PPI in combination with ZnI2 as a binary catalyst. Based on the kinetic study, a synergistic acid-based reaction mechanism was proposed.

关键词： Cycloaddition CO2 utilization Cyclic carbonates Homogeneous catalysis Activation energy

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

Plinthite and Its Associated Evolutionary Forms in Soils and Landscapes:A Review

引用

Pedosphere 2014年第2期24卷 153-166页

作者： P.N.eze T.K.UDEIGWE M.E.MEADOWS Department of Environmental & Geographical Science University of Cape Town Department of Plant and Soil Science Texas Tech University

At elevated temperature regimes and abundant precipitation, mobilization and accretion of weathered iron oxides are promoted especially in a reduced environments in the tropics. This may lead to the formation of plinthite, which hardens irreversibly upon repeated wetting and drying to form petroplinthite. The need for this review stems from the seemingly dearth of information on the subject and a need to clarify different terms used in describing plinthite. We review various research works on plinthite and its associated pedogenic forms in the tropics. Furthermore, we proffer recommendations as to the most appropriate land use management practices that could help minimise the environmental and agronomic problems associated with plinthite and its related pedogenic forms. Parent material, temperature, seasonality and geomorphology are critical factors that influence soil water regime which in turn affect the pedogenesis of plinthite. Soil pH and mineralogy are additional factors that could also promote plinthite formation. Fossil plinthic soils are potential proxies for palaeoenvironmental reconstruction. Measures used in the management of plinthic soils include mechanically breaking the hardpans and the use of organic and inorganic amendments to modify the structure and chemistry of the soils. Avoidance of practices that would predispose soils to erosion would also prevent plinthization. We call for the relinquishment of the term ＂[aterite＂ which is a generM term for all forms of iron oxide-enriched earthy materials as used for plinthite. Plinthic horizon should also be incorporated into the United States Department of Agriculture Soil Taxonomy in view of its growing importance in soils.

关键词： agronomy pedogenesis petroplinthite soil taxonomy tropics

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

Public＇s knowledge of the differences between ophthalmologists and optometrists：a critical issue in eye care service utilisation

引用

International Journal of Ophthalmology(English edition) 2016年第9期9卷 1336-1342页

作者： Boniface Ikenna eze Obiekwe Okoye Emmanuel Nwabueze Aguwa Department of Ophthalmology University of Nigeria Teaching Hospital PMB 01139 Ituku-Ozalla EnuguNigeria Department of Community Medicine and Public Health University of Nigeria Teaching Hospital PMB 01139Ituku-Ozalla Enugu Nigeria

AIM：To assess the public＇s knowledge of the differences between ophthalmologists and optometrists and identify the factors associated with ***：The study was a population-based random survey of adults aged 18 years or older conducted in Enugu,south eastern Nigeria,between March and June,*** on respondents＇ socio-demographics,clinical profile,and knowledge of the differences between ophthalmologists and optometrists were collected using a 28-item *** were analysed using descriptive and analytical *** of P〈0.05 were considered statistically ***：The respondents（P=394） comprised 198 males and 196 females（sex ratio =1.01：1）,aged 18-70（30.9 ±10.8） *** majority of respondents were single（57.4%）,possessed secondary education（96.9%）,employed（65.2%） and had no health insurance（77.4%）.Their clinical profile showed previous eye exam 54.1%,spectacle wear 41.6%and contact lens wear 5.6%.In the multivariate analysis,participants＇ good knowledge of the differences between ophthalmologists and optometrists was significantly associated with educational status（OR：0.32,95%CI：0.23-0.44,P〈0.0001,β =-0.988）,employment status（OR：1.8,95%CI：1.45-2.25,P〈0.0001,β=0.124）and previous eye examination（OR：1.63,95%CI：1.29-2.07,P〈0.0001,β =0.549）.CONCLUSION：Participants＇ socio-demographic and clinical characteristics are important predictors of good *** findings may have implications for all stakeholders in eye care *** is need for knowledge enhancement,by the government and eye care providers,through population-based eye health literacy campaigns.

关键词： public's knowledge ophthalmologists optometrists

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

Some Estimates of the Maximum Modulus for Polynomials with Gaps

引用

Analysis in Theory and Applications 2019年第4期35卷 421-426页

作者： eze R.Nwaeze Department of Mathematics Tuskegee UniversityTuskegeeAL 36088USA

Let p(z)be a polynomial of degree n having some zeros at a point z0 ∈C with |z0|<1 and the rest of the zeros lying on or outside the boundary of a prescribed *** this brief note,we consider this class of polynomials ... 详细信息

关键词： Polynomials maximum modulus zeros prescribed disk

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

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：