检索结果-内蒙古大学图书馆

mechanical Integrity and Failure Analysis of Photovoltaic Modules under Simulated Snow Loads Using Pneumatic Airbag Setup

引用

Journal of Power and Energy engineering 2022年第1期10卷 1-13页

作者： Nouman Ali Shah Rizwan M. Gul Zafar Hayat Khan State Key Laboratory of Polymer Materials Engineering College of Polymer Science and Engineering Sichuan University Chengdu China Department of Mechanical Engineering University of Engineering and Technology Peshawar Pakistan State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and Hydropower Sichuan University Chengdu China

Photovoltaic (PV) modules have emerged as an ideal technology of choice for harvesting vastly available renewable energy resources. However, the efficiency of PV modules remains significantly lower than that of other renewable energy sources such as wind and hydro. One of the critical elements affecting a photovoltaic module’s efficiency is the variety of external climatic conditions under which it is installed. In this work, the effect of simulated snow loads was evaluated on the performance of PV modules with different types of cells and numbers of busbars. According to ASTM-1830 and IEC-1215 standards, a load of 5400 Pa was applied to the surface of PV modules for 3 hours. An indigenously developed pneumatic airbag test setup was used for the uniform application of this load throughout the test, which was validated by load cell and pressure gauge. Electroluminescence (EL) imaging and solar flash tests were performed before and after the application of load to characterize the performance and effect of load on PV modules. Based on these tests, the maximum power output, efficiency, fill factor and series resistance were determined. The results show that polycrystalline modules are the most likely to withstand the snow loads as compared to monocrystalline PV modules. A maximum drop of 32.13% in the power output and a 17.6% increase in series resistance were observed in the modules having more cracks. These findings demonstrated the efficacy of the newly established test setup and the potential of snow loads for reducing the overall performance of PV module.

关键词： Photovoltaic Modules Pneumatic Testing Setup mechanical Integrity Electroluminescence Testing Electrical Performance

来源：评论

学校读者我要写书评

暂无评论

Origin of inhomogeneity in spark plasma sintered bismuth antimony telluride thermoelectric nanocomposites

引用

Nano Research 2020年第5期13卷 1339-1346页

作者： Enzheng Shi Shuang Cui Nicholas Kempf Qingfeng Xing Thomas Chasapis Huazhang Zhu Zhe Li Je-Hyeong Bahk G.Jeffrey Snyder Yanliang Zhang Renkun Chen Yue Wu Department of Chemical and Biological Engineering Iowa State UniversityAmesIA 50011USA Ames Laboratory Department of EnergyIowa State UniversityAmesIA 50011USA Department of Mechanical and Aerospace Engineering University of California-San DiegoLa JollaCA 92093USA Buildings and Thermal Sciences Center National Renewable Energy LaboratoryGoldenCO 80401USA Department of Aerospace and Mechanical Engineering University of Notre DameNotre DameIN 46556USA Department of Materials Science and Engineering Northwestern UniversityEvanstonIL 60208USA Department of Mechanical and Materials Engineering University of CincinnatiCincinnatiOH 45221USA

Anisotropy and inhomogeneity are ubiquitous in spark plasma sintered thermoelectric ***,the origin of inhomogeneity in thermoelectric nanocomposites has rarely been investigated so ***,we systematically study the impact of inhomogeneity in spark plasma sintered bismuth antimony telluride(BiSbTe)thermoelectric nanocomposites fabricated from solution-synthesized *** figure of merit can reach 1.18,which,however,can be overestimated to 1.88 without considering the *** study reveals that the inhomogeneity in thermoelectric properties is attributed to the non-uniformity of porosity,textures and elemental distribution from electron backscatter diffraction and energy-dispersive spectroscopy *** finding suggests that the optimization of bulk material homogeneity should also be actively pursued in any future thermoelectric material research.

关键词： bismuth antimony telluride solution synthesis thermoelectrics inhomogeneity

来源：评论

学校读者我要写书评

暂无评论

Application Research of Computational Design Aesthetics

Application Research of Computational Design Aesthetics

引用

Intelligent Design (ICID), International Conference on

作者： Ding Zhou Jiawei Huang Yukun Zhang Bingjian Liu School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China Department of Mechanical Materials and Manufacturing Engineering University of Nottingham Ningbo China Ningbo China

This study explores the application of computational design aesthetics to conform to Chinese aesthetic standards in customized glasses frames. Through quantitative analysis, it examines the impact of key design variables (upper frame position, middle beam height, and lower frame position) on the aesthetics of wearing. The results indicate that achieving a better aesthetic feeling can be attained when the upper frame of the glasses is approximately 20% above the vertical distance between the eyebrow and eye, the middle beam is about 20% above the height of the frame, or the lower frame is roughly 40% above the vertical distance between the lower eyelid and the angle of the mouth. These findings hold significant value for the eyewear industry and cultural confidence. They empower enterprises to leverage computational design tools, enhancing the harmony and attractiveness of individual facial frames, catering to the preferences of the Chinese market, and deepening the understanding of cultural factors in aesthetic perception. Furthermore, it contributes to realizing the goal of socialist cultural confidence with Chinese characteristics. In conclusion, this study is a valuable reference for creating eyewear frames that exude individual and cultural confidence, fostering innovation in the eyewear industry and the principles of harmonious design aesthetics.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Metallic Slurry Preparation and Printability Assessment For Material Extrusion Additive Manufacturing

SSRN

引用

SSRN 2023年

作者： Li, Zhong Hu, Xiaogang Zhou, Yang Qu, Wenying Wen, Linju Meng, Xiaoxia Xu, Zhen Guo, Chuan Lu, Hongxing Zhu, Qiang Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen518055 China Shenzhen Key Laboratory for Additive Manufacturing of High-performance materials Southern University of Science and Technology Shenzhen518055 China Department of Mechanical Engineering Sciences University of Surrey Surrey GuildfordGU2 7XH United Kingdom BYD Auto Industry Company Limited Shenzhen518118 China Department of Mechanical Engineering Polytechnic University of Milan Milan20156 Italy

Material extrusion additive manufacturing of thermoplastics is so advanced due to the tunable rheological properties and hence a suitable printability, which is deficient for metals. Even though semi-solid modification and binder indirect modification are used to realize metal extrusion printing, the uncontrollable flow behavior and the metallurgical defects make it challenging to bridge this gap. In this study, mixed powder remelting and printability assessment were first proposed for producing metallic slurry with pre-designed microstructure and suitable printability. Specifically, the hypoeutectic Sn-Bi metallic slurry was obtained by remelting the mixed powder composed of SnBi58 powder and pure Sn powder. The microstructural characteristics at different temperatures were investigated, demonstrating the ability of microstructure predesign. Furthermore, the printability, including stability, extrudability, and buildability, was evaluated by an advanced rheometer and a screw-type 3D printer. The combined slurry preparation, printability assessment, and printing experiment provides a systematic method for parameters improvement to obtain the structural fidelity. © 2023, The Authors. All rights reserved.

关键词： Microstructure

来源：评论

学校读者我要写书评

暂无评论

Anti-Termite Activity of Azadirachta excelsa Seed Kernel and Its Isolated Compound against Coptotermes curvignathus

Journal of the Korean Wood Science and Technology

引用

Journal of the Korean Wood science and Technology 2023年第3期51卷 157-172页

作者： Adfa, Morina Wiradimafan, Khafit Pratama, Ricky Febri Sanjaya, Angga Triawan, Deni Agus Yudha S., Salprima Ninomiya, Masayuki Rafi, Mohamad Koketsu, Mamoru Department of Chemistry Faculty of Mathematics and Natural Sciences University of Bengkulu Bengkulu38371 Indonesia Research Center of Sumatera Natural Product and Functional Materials University of Bengkulu Bengkulu38371 Indonesia Master of Chemistry Study Program Faculty of Mathematics and Natural Sciences University of Bengkulu Bengkulu38371 Indonesia Department of Chemistry and Biomolecular Science Faculty of Engineering Gifu University Gifu5011193 Japan Department of Chemistry Faculty of Mathematics and Natural Sciences IPB University Bogor16128 Indonesia Tropical Biopharmaca Research Center-Institute of Research and Community Services IPB University Bogor16128 Indonesia

Azadirachta excelsa, is a plant belonging to the same genus as Indian neem (Azadirachta indica), and its use as a pesticide is reported by few studies. Despite being a different species, it is expected to have the same biopesticide potential as A. indica. Therefore, this study aims to investigate the anti-termite activity of n-hexane and methanol extracts of A. excelsa seed kernel at various concentrations against Coptotermes curvignathus. The methanol extract demonstrated greater termicidal activity than n-hexane at doses test of 2%, 4%, and 8%. It also showed 100% termite mortality on the third day of administering the 8% dose. According to the gas chromatography with mass spectrometry data, the putative main components of the n-hexane extract were hexadecanoic acid, ethyl ester (18.99%), 9,12-octadecadienoic acid (Z,Z)-(16.31%), and 9-octadecenal (16.23%). In contrast, the principal constituents of methanol extract were patchouli alcohol (28.1%), delta-guaiene (15.15%), and alpha-guaiene (11.93%). Furthermore, limonoids profiling of A. excelsa methanol extract was determined using Ultrahigh-performance liquid chromatography coupled with quadrupole-Orbitrap high-resolution mass spectrometry. The number of limonoids identified tentatively was fifteen, such as 6-deacetylnimbin, nimbolidin C, nimbolide, 6-acetylnimbandiol, 6-deacetyl-nimbinene, salannol, 28-deoxonimbolide, gedunin, nimbandiol, epoxyazadiradione, azadirone, 2',3'-dihydrosalannin, marrangin, nimbocinol, and azadirachtin. They were the same as those reported in the seed and leaves of A. indica, but its largest component in A. excelsa was 6-deacetylnimbin. As a result, the presence of these compounds may be responsible for the anti-termite activity of A. excelsa seed kernel extract. Additionally, column chromatography of methanol extract yielded 6-deacetylnimbin, which was found to be antifeedant and termiticide against C. curvignathus. © 2023 The Korean Society of Wood science & Technology.

关键词： Mass spectrometry

来源：评论

学校读者我要写书评

暂无评论

Simulations of multivariant Si I to Si II phase transformation in polycrystalline silicon with finite-strain scale-free phase-field approach

arXiv

引用

arXiv 2023年

作者： Babaei, Hamed Pratoori, Raghunandan Levitas, Valery I. Department of Aerospace Engineering Iowa State University AmesIA50011 United States Departments of Mechanical Engineering Iowa State University AmesIA50011 United States Ames Laboratory Division of Materials Science and Engineering AmesIA50011 United States

Scale-free phase-field approach (PFA) at large strains and corresponding finite element method (FEM) simulations for multivariant martensitic phase transformation (PT) from cubic Si I to tetragonal Si II in a polycrystalline aggregate are presented. Important features of the model are large and very anisotropic transformation strain tensor ΕΕt = {0.1753;0.1753;−0.447} and stress-tensor dependent athermal dissipative threshold for PT, which produce essential challenges for computations. 3D polycrystals with 55 and 910 stochastically oriented grains are subjected to uniaxial strain- and stress-controlled loadings under periodic boundary conditions and zero averaged lateral strains. Coupled evolution of discrete martensitic microstructure, volume fractions of martensitic variants and Si II, stress and transformation strain tensors, and texture are presented and analyzed. Macroscopic variables effectively representing multivariant transformational behavior are introduced. Macroscopic stress-strain and transformational behavior for 55 and 910 grains are close (less than 10% difference). This allows the determination of macroscopic constitutive equations by treating aggregate with a small number of grains. Large transformation strains and grain boundaries lead to huge internal stresses of tens GPa, which affect microstructure evolution and macroscopic behavior. In contrast to a single crystal, the local mechanical instabilities due to PT and negative local tangent modulus are stabilized at the macroscale by arresting/slowing the growth of Si II regions by the grain boundaries and generating the internal back stresses. This leads to increasing stress during PT. The developed methodology can be used for studying similar PTs with large transformation strains and for further development by including plastic strain and strain-induced PTs. © 2023, CC BY.

关键词： Polycrystals

来源：评论

学校读者我要写书评

暂无评论

Unusual effects of vacuum annealing on large-area Ag_(3)PO_(4) microcrystalline film photoanode boosting cocatalyst-and scavengerfree water splitting

引用

Journal of Materiomics 2021年第5期7卷 929-939页

作者： Qi Cao Jun Yu Yue Cao Jean-Jacques Delaunay Renchao Che Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy and EnvironmentSoutheast UniversityNanjing210096China Department of Mechanical Engineering School of EngineeringThe University of TokyoTokyo113-8656Japan Laboratory of Advanced Materials Department of Materials ScienceAnd Collaborative Innovation Center of Chemistry for Energy Materials(iChEM)Fudan UniversityShanghai200438China Guangdong Provincial Key Laboratory of Nano-Micro Materials Research School of Chemical Biology and BiotechnologyPeking University Shenzhen Graduate SchoolShenzhen518055China Department of Chemistry School of ScienceThe University of TokyoTokyo113-8656Japan

Ag_(3)PO_(4) as a novel photoanode material,despite its arguably highest photoactivity,suffers for its poor light absorption and stability for photoelectrochemical(PEC)water *** this work,4.54.5 cm^(2) Ag_(3)PO_(4) microcrystalline films are grown via a room-temperature solution process,and vacuum annealing is proposed to solve the stability and light absorption *** is found that the major process below 400℃ of vacuum annealing is the|Recovery|process for Ag_(3)PO_(4) microcrystals,when lattice defects and Ag0 surface species get ***,|Recrystallization|stage occurs at>40℃.The recovery of native defects of silver vacancies,with both density functional theory calculation and experimental results,could simultaneously improve the light absorption and catalytic activity of Ag_(3)PO_(4).The 400℃-annealed Ag_(3)PO_(4) photoanode,with enhanced light harvesting and crystal quality,exhibits 88% increase in(Jlight-Jdark)value(1.94 mA cm^(-2))than non-annealed photoanode(1.03 mA cm^(-2)).Moreover,it retains>99% current density after a 4000-s stability *** results suggest that vacuum annealing can substantially improve the PEC performance of Ag_(3)PO_(4) microcrystalline film photoanodes due to mitigated effects of native defects,improved light harvesting,and inhibited Ag_(3)PO_(4) decomposition during water oxidation reaction.

关键词： Orthophosphate Defect engineering Light harvesting Oxygen evolution reaction(OER) Hydrogen production Post-annealing

来源：评论

学校读者我要写书评

暂无评论

Nonlocal Nernst-Planck-Poisson System for Modeling Electrochemical Corrosion in Biodegradable Magnesium Implants

引用

Journal of Peridynamics and Nonlocal Modeling 2025年第1期7卷 1-32页

作者： Hermann, Alexander Shojaei, Arman Höche, Daniel Jafarzadeh, Siavash Bobaru, Florin Cyron, Christian J. Institute of Material Systems Modeling Helmholtz-Zentrum Hereon Max-Planck-Str. 1 21502 Geesthacht Germany Institute of Surface Science Helmholtz-Zentrum Hereon Max-Planck-Str. 1 21502 Geesthacht Germany Department of Mathematics Lehigh University Bethlehem 18015 PA United States Department of Mechanical & amp Materials Engineering University of Nebraska-Lincoln Lincoln 68588-0526 NE United States Institute for Continuum and Material Mechanics Hamburg University of Technology Eissendorfer Strasse 42 Hamburg 21073 Germany

This paper provides a comprehensive derivation and application of the nonlocal Nernst-Planck-Poisson (NNPP) system for accurate modeling of electrochemical corrosion with a focus on the biodegradation of magnesium-based implant materials under physiological conditions. The NNPP system extends and generalizes the peridynamic bi-material corrosion model by considering the transport of multiple ionic species due to electromigration. As in the peridynamic corrosion model, the NNPP system naturally accounts for moving boundaries due to the electrochemical dissolution of solid metallic materials in a liquid electrolyte as part of the dissolution process. In addition, we use the concept of a diffusive corrosion layer, which serves as an interface for constitutive corrosion modeling and provides an accurate representation of the kinetics with respect to the corrosion system under consideration. Through the NNPP model, we propose a corrosion modeling approach that incorporates diffusion, electromigration and reaction conditions in a single nonlocal framework. The validity of the NNPP-based corrosion model is illustrated by numerical simulations, including a one-dimensional example of pencil electrode corrosion and a three-dimensional simulation of a Mg-10Gd alloy bone implant screw decomposing in simulated body fluid. The numerical simulations correctly reproduce the corrosion patterns in agreement with macroscopic experimental corrosion data. Using numerical models of corrosion based on the NNPP system, a nonlocal approach to corrosion analysis is proposed, which reduces the gap between experimental observations and computational predictions, particularly in the development of biodegradable implant materials. © The Author(s) 2024.

关键词： Biodegradation Corrosion modeling Electromigration Implant materials Nernst-Planck-Poisson system Peridynamics

来源：评论

学校读者我要写书评

暂无评论

Influence of stacking sequences of woven jute-carbon hybrid composites: Diffusion mechanism and mechanical characterization

引用

Heliyon 2024年第17期10卷 e36632页

作者： Alvy, Md Sadbin Azad Hossain, Md Foisal Rana, Muhammed Sohel Rahman, Md Motinur Ferdous, Md Shafiul Department of Materials Science and Engineering Khulna University of Engineering & Technology Khulna 9203 Bangladesh Department of Electronics and Communication Engineering Khulna University of Engineering & Technology Khulna 9203 Bangladesh Central Engineering Facilities Atomic Energy Research Establishment Savar Dhaka 1349 Bangladesh Institute of Electronics Bangladesh Atomic Energy Commission Dhaka 1349 Bangladesh Former Faculty Department of Mechanical Engineering Khulna University of Engineering & Technology Khulna 9203 Bangladesh

In this study, different stacking orders of carbon-jute fiber mats were used to fabricate the composites and hybrids. The impact of different stacking orientations on mechanical properties was investigated experimentally. The experimental results were verified by finite element analysis (FEA). In addition, the impact of the fiber orientation on the loading direction was also investigated. Four layers of fabrics were piled to fabricate the composites by hand-layup with the cold press process. A NaCl solution was used to create a corrosive medium (pH 8), and the composites and hybrids were immersed in that medium, and their mechanical properties were compared. In this research, it has been found that the laminates with the stacking sequence of type-C (C/J/J/C) show the best result among other composites. Jute composites where all the fibers are in the loading direction possess a high strain compared with the other composites and hybrids. On the scanning electron microscope (SEM) image, delamination, buckling of fiber, fiber pullout, and voids were observed. In addition, the kinetics of the diffusion mechanism were also investigated, and it was found from the experimental results that the composites and hybrids immersed in pH 8 absorbed water via Fickian diffusion. © 2024 The Authors

关键词： Composites Corrosive impact Diffusion mechanism FEM Flexural strength Tensile strength

来源：评论

学校读者我要写书评

暂无评论

Chiral, Topological, and Knotted Colloids in Liquid Crystals

arXiv

引用

arXiv 2024年

作者： Yuan, Ye Smalyukh, Ivan I. Hiroshima University Hiroshima Higashi-Hiroshima739-8526 Japan Department of Physics Department of Electrical Computer and Energy Engineering Materials Science and Engineering Program Soft Materials Research Center University of Colorado BoulderCO80309 United States Renewable and Sustainable Energy Institute National Renewable Energy Laboratory University of Colorado BoulderCO80309 United States

The geometric shape, symmetry, and topology of colloidal particles often allow for controlling colloidal phase behavior and physical properties of these soft matter systems. In liquid crystalline dispersions, colloidal particles with low symmetry and nontrivial topology of surface confinement are of particular interest, including surfaces shaped as handlebodies, spirals, knots, multi-component links, and so on. These types of colloidal surfaces induce topologically nontrivial three-dimensional director field configurations and topological defects. Director switching by electric fields, laser tweezing of defects, and local photo-thermal melting of the liquid crystal host medium promote transformations among many stable and metastable particle-induced director configurations that can be revealed by means of direct label-free three-dimensional nonlinear optical imaging. The interplay between topologies of colloidal surfaces, director fields, and defects is found to show a number of unexpected features, such as knotting and linking of line defects, often uniquely arising from the nonpolar nature of the nematic director field. This review article highlights fascinating examples of new physical behavior arising from the interplay of nematic molecular order and both chiral symmetry and topology of colloidal inclusions within the nematic host. Furthermore, the article concludes with a brief discussion of how these findings may lay the groundwork for new types of topology-dictated self-assembly in soft condensed matter leading to novel mesostructured composite materials, as well as for experimental insights into the pure-math aspects of low-dimensional topology. © 2024, CC BY.

关键词： Crystal symmetry

来源：评论

学校读者我要写书评

暂无评论

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

请选择保存的检索档案：

请选择收藏分类：

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

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

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：