检索结果-南通市图书馆

A Non-Intrusive Stochastic Phase-Field for Fatigue Fracture in Brittle Materials with Uncertainty in Geometry and Material Properties

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2024年第11期141卷 997-1032页

作者： Rajan Aravind Sundararajan Natarajan Krishnankutty Jayakumar Ratna Kumar Annabattula Department of Mechanical Engineering Indian Institute of Technology MadrasChennai600036India Vikram Sarabhai Space Centre Thiruvananthapuram695022India

Understanding the probabilistic nature of brittle materials due to inherent dispersions in their mechanical properties is important to assess their reliability and safety for sensitive engineering *** is all the more important when elements composed of brittle materials are exposed to dynamic environments,resulting in catastrophic fatigue *** authors propose the application of a non-intrusive polynomial chaos expansion method for probabilistic studies on brittle materials undergoing fatigue fracture when geometrical parameters and material properties are random independent *** the probabilistic nature of fatigue fracture in brittle materials is crucial for ensuring the reliability and safety of engineering structures subjected to cyclic *** growth is modelled using a phase-field approach within a finite element *** modelling fatigue,fracture resistance is progressively degraded by modifying the regularised free energy functional using a fatigue degradation *** of cycles to failure is treated as the dependent variable of interest and is estimated within acceptable limits due to the randomness in independent *** 2D benchmark problems are solved to demonstrate the ability of this approach to predict the dependent variable responses with significantly fewer simulations than the Monte Carlo *** proposed approach can accurately predict results typically obtained through 105 or more runs in Monte Carlo simulations with a reduction of up to three orders of magnitude in required *** independent random variables’sensitivity to the system response is determined using Sobol’*** proposed approach has low computational overhead and can be useful for computationally intensive problems requiring rapid decision-making in sensitive applications like aerospace,nuclear and biomedical *** technique does not require reformulating existing finite element code and can

关键词： Phase-field fatigue fracture polynomial chaos expansion material uncertainty random variables non-intrusive stochastic technique

Effect of dual and new generation wide-base tire assembly on inverted pavements

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Road Engineering 2022年第2期2卷 124-136页

作者： Rajan Singh Baghel Sridhar Reddy Kasu Anush K.Chandrappa School of Infrastructure Indian Institute of Technology BhubaneswarOdisha 752050India Department of Civil Engineering Sreyas Institute of Engineering and TechnologyHyderabad 500068India

The conventional flexible pavements have been constructed such that the stiffness of the layer reduces with *** crust thickness becomes significantly high for heavy traffic corridors resulting in the consumption of large quantities of construction materials and also increasing environmental *** pavements with the aggregate interlayer(AIL)or stress absorbing membrane interlayer(SAMI)are considered to be one of the alternatives for thick conventional flexible pavements for heavy traffic *** AIL or SAMI is placed between a stiff cement-treated base and asphalt concrete layer to function as crack relief *** change in the composition alters the behaviour of inverted pavements compared to the conventional flexible *** the other hand,wide-base tires are being increasingly preferred by trucking industries due to increased fuel economy and cargo ***,the effect of wide-base tires on the performance of inverted pavements is yet to be *** this study,the 3D finite element(FE)models of inverted pavements considering different crack relief layers were developed,and load from dual-wheel and wide-base tires were *** stress-strain evolution in the various layers of inverted pavements was investigated and discussed in this *** results indicated the higher stress and strains due to wide base tires compared to the dual-wheel ***,pavement with SAMI was found to result in lower stress and strains in the asphalt concrete layer compared to AIL pavements.

关键词： Aggregate interlayer Inverted pavement Shear strain Stress absorbing membrane interlayer Wide-base tire

Assessment of renewable energy:Status,challenges,COVID-19 impacts,opportunities,and sustainable energy solutions in Africa

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

Energy and Built Environment 2022年第3期3卷 348-362页

作者： Mohammad Amir Sana Zubair Khan Department of Electrical Engineering Faculty of Engineering and TechnologyJamia Millia Islamia(Central University)New Delhi 110025India Amity Institute of Environmental Science(AIES) Amity UniversityNoidaUttar Pradesh 201313India

Today’s more focus and efforts are being put by all the energy leaders towards power generation using renewable energy ***,these resources are becoming affordable to facilitate a swift shift towards green and clean *** strategic assets are an add-on for all the developing nations in terms of *** technological advancement and power market revolution resulting in an adequate reduction of renewable energy cost and *** paper mainly focusing on Covid-19 impacts in the African energy ***,analyzing recent developments in African renewable energy generation that holds the immense capacity for *** paper highlighting the recommendations in response to the COVID-19 pandemic for the African renewable energy *** paper is a result of rigorous analysis based on major issues governing sustainable solutions for *** review paper comes up with effective conclusions to address the challenges in the cur-rent pandemic *** Africa abundance of resources is found with huge potential for the generation of *** still,Africa undergoing a phase of serious crises because they are not able to tap its huge capital of renewable *** is a subsequent need for power grid restructuring,energy storage technologies,and parallel mitigation of environmental factors with seasonal *** review analysis bringing a better opportunity for all issues towards sustainable solutions,that will ease the renewable energy status in *** is observed that there is an inevitable need to focus on having strong government policy frameworks and proper *** various recommendations are required to swing towards renewable energy ***-bined efforts are required in luring foreign investments and to address feasible issues like setting-up *** paper demonstrated a smart energy system using a proposed machine learning-based framework for enhancing the PV forecasting an

关键词： Artificial intelligence COVID-19 CO_(2)emission International Solar Alliance(ISA) Renewable Energy Resources(RER) Western Africa Power Pool

Enhancement of methane yield from cotton stalks by mechanical pre-treatment

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Carbon Resources Conversion 2021年第1期4卷 164-168页

作者： Rafat Al Afif Christoph Pfeifer Institute of Chemical and Energy Engineering University of Natural Resources and Life SciencesViennaMuthgasse 107Vienna 1190Austria

Cotton stalks(CS)are lignocellulosic agricultural by-products,a potential source for biogas production,but pretreatment must be considered since hydrolysis is the rate-limiting stage for lignocellulosic biomass *** study investigates the feasibility of mechanical pretreatment of CS to enhance methane *** anaerobic digestion of CS samples with particle sizes ranging from 0.5 to 65 mm was carried out in 1 L eudiometer batch digesters for 48 days at 37◦*** showed that methane yield was inversely proportional to particle size,and the quality of biogas was good(54.0-55.2%CH_(4)).Significant increases in methane yield were observed with 20.3%and 26%for samples with a particle size of 3 mm and 0.5 mm,respectively,compared to untreated *** coefficient of anaerobic energy turnover was relatively low(20.2-25.5%).Reduction of the CS particle size to 3 mm or less is recommended to achieve effective methane conversion and decrease the retention time in an anaerobic digester from 31 to about 25 ***,to offset the high energy demand required for grinding,further research should be conducted in combining size reduction with chemical and physicochemical pretreatment.

关键词： Cotton stalks Anaerobic digestion Methane yield Mechanical pretreatment

Geochemistry of arsenic and selenium in a Ge-poor coal from the Wulantuga coal-hosted Ge ore deposit,Inner Mongolia,North China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Coal Science & Technology 2014年第4期1卷 383-389页

作者： Panpan Xie Qingqian Li Jingjing Liu Hongjian Song Jianpeng Wei College of Geoscience and Surveying Engineering China University of Mining and Technology(Beijing)Beijing 100083China

This paper reports new data for arsenic(As)and selenium(Se)in a total of twelve bench samples of Ge-rich and Ge-poor coals in the No.6 coal seam from the Wulantuga ore deposit,Inner Mongolia,Northeastern *** Gepoor coals are characterized by low-ash(with a weighted average ash yield 10.59%).The coal samples were digested using an UltraClave microwave high pressure reactor(milestone)and trace elements were detected by inductively coupled plasma mass spectrometry—collision/reaction cell technology,a reliable method for As and Se determination in coal *** contents of As and Se in the Ge-poor(with a weighted average content of 9.14 and 0.30 lg/g,respectively)and Ge-rich coal samples in the present study(varies from 16.88 to 17,776 lg/g and from 0.26 to 14.39 lg/g,respectively)are in a sharp *** As in the Ge-poor coals is of both organic-and pyrite-associations,and its enrichment is attributed to the sediment source,and to a lesser extent,to hydrothermal *** is predominantly connected with organic matter in the Wulantuga Ge-poor coals.

关键词： Arsenic Selenium Wulantuga Ge ore deposit

A Novel Analytical Technique of the Fractional Bagley-Torvik Equations for Motion of a Rigid Plate in Newtonian Fluids

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2020年第9期124卷 969-983页

作者： Mahmoud H.Taha Mohamed A.Ramadan Dumitru Baleanu Galal M.Moatimid Department of Mathematics Faculty of EducationAin Shams UniversityCairoEgypt Department of Mathematics&Computer Science Faculty of ScienceMenoufia UniversityShebin El-KomEgypt Department of Mathematics Cankaya UniversityAnkara06530Turkey Institute of Atomic Physics Magurele-Bucharest077125Romania Department of Medical Research China Medical University HospitalChina Medical UniversityTaichungTaiwan

The current paper is concerned with a modified Homotopy perturbation *** modification allows achieving an exact solution of an initial value problem of the fractional differential *** approach is powerful,effective,and promising in analyzing some classes of fractional differential equations for heat conduction problems and other dynamical *** crystallize the new approach,some illustrated examples are introduced.

关键词： Bagley-Torvik equation caputo sense Riemann-Liouville integral fractional differential equation

Overall eVTOL aircraft design for urban air mobility

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Green Energy and Intelligent Transportation 2024年第2期3卷 9-19页

作者： Jiechao Zhang Yaolong Liu Yao Zheng School of Aeronautics and Astronautics Zhejiang UniversityHangzhou 310027China

Electric vertical takeoff and landing(eVTOL)aircraft have emerged as a potential alternative to the existing transportation system,offering a transition from two-dimensional commuting and logistics to three-dimensional *** a groundbreaking innovation in both the automotive and aviation sectors,eVTOL holds significant promise but also presents notable *** paper aims to address the overall aircraft design(OAD)approach specifically tailored for eVTOL in the context of Urban Air Mobility(UAM).In contrast to traditional OAD methods,this study introduces and integrates disciplinary methodologies specifically catered to eVTOL aircraft design.A case study is conducted on a tilt-duct eVTOL aircraft with a typical UAM mission,and the disciplinary performance,including initial sizing,aerodynamics,electric propulsion systems,stability and control,weight,mission analysis and noise,is examined using the OAD *** findings demonstrate that the current approach effectively evaluates the fundamental aircraft-level performance of eVTOL,albeit further high-fidelity disciplinary analysis and optimization methods are required for future MDO-based eVTOL overall aircraft design.

关键词： Electric vertical takeoff and landing Urban air mobility Overall aircraft design Tilt-duct

Chitosan based bioactive materials in tissue engineering applications-A review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Bioactive Materials 2020年第1期5卷 164-183页

作者： Md.Minhajul Islam Md.Shahruzzaman Shanta Biswas Md.Nurus Sakib Taslim Ur Rashid Department of Applied Chemistry and Chemical Engineering Faculty of Engineering and TechnologyUniversity of DhakaDhaka1000Bangladesh Fiber and Polymer Science North Carolina State UniversityCampus Box 7616RaleighNC27695United States

In recent years,there have been increasingly rapid advances of using bioactive materials in tissue engineering *** materials constitute many different structures based upon ceramic,metallic or polymeric materials,and can elicit specific tissue ***,most of them are relatively brittle,stiff,and difficult to form into complex ***,there has been a growing demand for preparing materials with tailored physical,biological,and mechanical properties,as well as predictable degradation ***-based materials have been shown to be ideal bioactive materials due to their outstanding properties such as formability into different structures,and fabricability with a wide range of bioactive materials,in addition to their biocompatibility and *** review highlights scientific findings concerning the use of innovative chitosan-based bioactive materials in the fields of tissue engineering,with an outlook into their future *** also covers latest developments in terms of constituents,fabrication technologies,structural,and bioactive properties of these materials that may represent an effective solution for tissue engineering materials,making them a realistic clinical alternative in the near future.

关键词： Chitosan Bioactive material Scaffold Tissue engineering

Estimating the geographic range of a threatened shark in a data-poor region： Cetorhinus maximus in the South Atlantic Ocean

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2015年第5期61卷 811-826页

作者： Luis O. LUCIFORA Santiago A. BARBINI Edgardo E. DI GIACOMO Juan A. WAESSLE Daniel E. FIGUEROA Instituto de Biologia Subtropical - Iguazu Consejo Nacional de Investigaciones Cientificas y Tecnicas Universidad Nacional de Misiones Puerto Iguazu Misiones Argentina Laboratorio de Ictiologia Instituto de Investigaciones Marinas y Costeras Consejo Nacional de Investigaciones Cientificas y Tecnicas Universidad Nacional de Mar del Plata Mar del Plata Provincia de Buenos Aires Argentina Grupo Condros Instituto de Biologia Marina y Pesquera "Almirante Stomi" Universidad Nacional del Comahue San Antonio Oeste Rio Negro Argentina Instituto Nacional de Investigacion y Desarrollo Pesquero Mar del Plata Provincia de Buenos Aires Argentina

The distribution of the planktivorous basking shark Cetorhinus maximus is influenced by zooplankton abundance at small scales and temperature at medium scales in the North Atlantic. Here, we estimate the distribution of basking sharks on South Atlantic continental shelves, and the relative importance of chlorophyll concentration, as a proxy for zooplankton abun- dance, and temperature in determining habitat suitability for basking sharks at large scales. We used maximum entropy （MaxEnt） and maximum likelihood （MaxLike） species distribution modelling to test three hypotheses： the distribution of basking sharks is determined by （1） temperature, （2） chlorophyll concentration, or （3） both chlorophyll and temperature, while considering other factors, such as oxygen and salinity. Off South America, basking shark habitat included subtropical, temperate and cool-temperate waters between approximately 20°S and 55°S. Off Africa, basking shark habitat was limited to cool-temperate waters off Namibia and southern South Africa. MaxLike models bad a better fit than MaxEnt models. The best model included minimum chlorophyll concentration, dissolved oxygen concentration, and sea surface temperature range, supporting hypothesis 3. However, of all variables included in the best model, minimum chlorophyll concentration had the highest influence on basking shark distribution. Unlike the North Atlantic distribution, the South Atlantic distribution of basking sharks includes subtropical and cool-temperate waters. This difference is explained by high minimum chlorophyll concentration off southern Brazil as compared to North Atlantic subtropical areas. Observations in other regions of the world support this conclusion. The highest habitat suitability for basking sharks is located close to nearshore areas that experience high anthropogenic impact [Current Zoology 61 （5）： 811-826, 2015].

关键词： Basking shark Chondrichthyes Geographic range MaxEnt MaxLike Southern Hemisphere