检索结果-内蒙古大学图书馆

Study on the Flow, Foaming Characteristics and Structural Strength of Polypropylene Structural Foam Injection Molding by Innovative Nitrogen and Molten Plastic Mixing Mechanism

引用

Polymers 2023年第9期15卷 2116-2116页

作者： Huang, Po-Wei Peng, Hsin-Shu Hwang, Sheng-Jye Huang, Chao-Tsai Program of Mechanical and Aeronautical Engineering Feng Chia University of Engineering and Science Taichung407102 Taiwan Department of Mechanical and Computer Aided Engineering Feng Chia University of Engineering and Science Taichung407102 Taiwan Department of Mechanical Engineering National Cheng Kung University of Engineering Tainan70101 Taiwan Department of Chemical and Materials Engineering Tamkang University of Engineering New Taipei City251301 Taiwan

Plastic foam molding methods include thermoforming, extrusion and injection molding. Injection foam molding is a one-time molding method with high production efficiency and good product quality. It is suitable for foamed plastic products with complex shapes and strict size requirements. It is also the main method for producing structural bubbles. In this investigation, we developed a structural foam injection molding technology using the gas supply equipment connected to the unique plasticizing mechanism of the injection machine and studied its influence on the specimens’ melt rheology quality and foam structures. In the experiment, the forming material was polypropylene (PP), and the gas for mixing/forming foaming characteristics was nitrogen (N2). Additionally, in order to observe the rheological properties of N2/melt mixing, a melt flow specimen mold cavity was designed and the change in the melt viscosity index was observed using a melt pressure sensing element installed at the nozzle position. With the nitrogen supply equipment connected to a unique plasticizing mechanism, the mixing of gas and molten plastic can be achieved at the screw plasticizing stage, where the foaming effect is realized during the melt-filling process due to the thermodynamic instability of the gas. It was also found that an increase in N2 fill content increased melt fluidity, and the trend of melt pressure and melt viscosity index showed that the higher the gas content, the lower the trend. The foaming characteristic depends on the gas thermodynamic instability and the pressure release, so it can be seen from the melt fill path that, the greater the pressure near the gate, the lower the foaming amount and the internal structure (SEM) after molding;the farther from the gate, the greater the relative increase in the foaming growth/amount. This phenomenon will be more obvious when the N2 fill content is increased. © 2023 by the authors.

关键词： Gases

来源：评论

学校读者我要写书评

暂无评论

The Application of 3D Printing Technology in Fabrication of Calcium Phosphate-based Biomaterials for Bone Repairment 22

The Application of 3D Printing Technology in Fabrication of ...

引用

12th International Conference on Biomedical engineering and Technology, ICBET 2022

作者： Lu, Jingyi Wang, Zhongchao Zhao, Zhihuan Song, Weihai Yu, Huijun Chen, Chuanzhong Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of Education Shandong Engineering & Technology Research Center for Superhard Material School of Materials Science and Engineering Shandong University Shandong University China School of Mechanical and Electronic Engineering Shandong Agricultural and Engineering University China

ISBN: (纸本)9781450395779

Bone defect has become a common disease threatening people's health. 3D-printed Calcium phosphate (CaP) is endowed with porous structure, proper mechanical properties and biological properties thus widely considered as an ideal bone substitutive material used for bone repairment. Herein, we reviewed the application of 3D-printing technology in generating CaP-based implants. Among 3D-printing techniques, binder jetting method has been widely applied to print CaP scaffolds since it is convenient and stable. Cubic structure is the most common shape of 3D-printed implants while patient-specific scaffold achieved by computed tomography scan is more preferred for clinical cases. Unified and interconnected porous structure of CaP scaffold desired for excellent biological performance can be obtained by 3D printing technique. Besides, loading bone morphogenetic protein and drugs on printed scaffold is proved to be an effective way to enhance vascularization and antibacterial ability. Most of the 3D-printed CaP scaffolds possess great mechanical strength within the range of 20-500 MPa to meet the requirement of load condition at defect site. Sintering process after printing is vital for achievement of better mechanical properties, sinter method and sinter temperature have marked effects on compressive strength of CaP implants. Finally, limitations and outlook of 3D-printing are summerized in the end. © 2022 ACM.

关键词： Calcium phosphate

来源：评论

学校读者我要写书评

暂无评论

Local Control of Microstructure and mechanical Properties Of High-Strength Steel in Electric Arc-Based Additive Manufacturing

SSRN

引用

SSRN 2023年

作者： Babu, Aravind Ebrahimi, Amin Wu, Kuo-Hao Richardson, Ian Malcom Hermans, Marcel J.M. Department of Material Science and Engineering Faculty of Mechanical Maritime and Materials Engineering Delft University of Technology Delft2628CD Netherlands

Additive manufacturing (AM) offers a significant potential for producing metallic parts with distinctly localised microstructures and mechanical properties, commonly referred to as functional grading. Functional grading in metal additive manufacturing is frequently accomplished through variations in composition or the implementation of in-situ thermo-mechanical techniques. Focusing on the electric arc-based additive manufacturing process, this study investigates the functional grading of high-strength steel (S690 grade) using a new technique by adjusting the travel speed and inter-pass temperature. It is demonstrated, through a combination of thermal simulations and experimental measurements on single bead-on-plate depositions, that the microstructure and the mechanical properties of parts manufactured through electric arc-based additive manufacturing can be controlled through the rational adjustment of process parameters. To exhibit functional grading, a rectangular block was fabricated using a constant wire feed rate of 6 m min−1, while the travel speed was varied. The rectangular block consisted of a region of low heat input (LHI) deposited with a travel speed of 20 mm s−1, situated between two zones of high heat input (HHI) that were deposited with a travel speed of 8 mm s−1. The results of the microstructural characterization revealed that the HHI zones were composed of a mixture of polygonal ferrite, acicular ferrite, and bainite, while the LHI region was primarily comprised of martensite. The hardness and profilometry-based indentation plastometry (PIP) measurements indicated that the LHI region exhibited higher hardness and strength, but lower elongation, compared to the HHI zones. The microstructural variation and associated changes in mechanical properties observed in this study demonstrate the potential to achieve functional grading by adjusting process parameters in electric arc-based additive manufacturing. © 2023, The Authors. All rights reserved.

关键词： 3D printing

来源：评论

学校读者我要写书评

暂无评论

Performance Evaluation of Partially Filled Metal Foam Channels for Improved Thermal-Hydraulic Performance in Forced Convections

SSRN

引用

SSRN 2023年

作者： Sonavane, Prasad Deepak Mahajan, Roop L. aDepartment of Mechanical Engineering Virginia Tech. Blacksburg 24061 VA USA bDepartment of Mechanical Engineering Department of Material Science and Engineering Virginia Tech. Blacksburg 24061 VA USA

In this paper, we report the findings of a thesis to investigate the potential for reducing pumping power penalty in channels partially filled with metal foams while maintaining thermal performance. The thermal-hydraulic performance parameter J/F1/3, where J is the Colburn-J factor and F is the friction factor was used to compare the relative performance of foams at various values of blockage fractions (B), where B is defined as the ratio of the height of the foam to the height of the channel. The metal foam samples considered were 10 PPI 6101-T6 Aluminum, with porosity of ∼ 94-96%, and B of 1/6, 1/3, 2/3, 5/6, and 1. The Reynolds number (based on the channel hydraulic diameter and inlet velocity) was varied from 1,000 to 15,000. A modification was made to all configurations with B © 2023, The Authors. All rights reserved.

关键词： Forced convection

来源：评论

学校读者我要写书评

暂无评论

Interactive Robot-Environment Self-Calibration via Compliant Exploratory Actions

Interactive Robot-Environment Self-Calibration via Compliant...

引用

IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

作者： Podshara Chanrungmaneekul Kejia Ren Joshua T. Grace Aaron M. Dollar Kaiyu Hang Department of Computer Science Rice University Houston TX USA Department of Mechanical Engineering and Material Science Yale University New Haven CT USA

ISBN: (数字)9798350377705

ISBN: (纸本)9798350377712

Calibrating robots into their workspaces is crucial for manipulation tasks. Existing calibration techniques often rely on sensors external to the robot (cameras, laser scanners, etc.) or specialized tools. This reliance complicates the calibration process and increases the costs and time requirements. Furthermore, the associated setup and measurement procedures require significant human intervention, which makes them more challenging to operate. Using the built-in force-torque sensors, which are nowadays a default component in collaborative robots, this work proposes a self-calibration framework where robot-environmental spatial relations are automatically estimated through compliant exploratory actions by the robot itself. The self-calibration approach converges, verifies its own accuracy, and terminates upon completion, autonomously purely through interactive exploration of the environment’s geometries. Extensive experiments validate the effectiveness of our self-calibration approach in accurately establishing the robot-environment spatial relationships without the need for additional sensing equipment or any human intervention.

关键词： Accuracy Robot vision systems Estimation Measurement by laser beam Cameras Probabilistic logic Sensor systems Calibration Robots Intelligent sensors

来源：评论

学校读者我要写书评

暂无评论

Drying of Industrial Sanitary Ware at Low Temperature: A Theoretical and Experimental Investigation

引用

Defect and Diffusion Forum 2023年 429卷 152-161页

作者： Gomez, Ricardo Soares Gomes, Kelly Cristiane Gurgel, José Maurício Alves de Matos da Silva, Fabio Emanuel França Alves, Laís Belizário Magalhães, Hortência Luma Fernandes de Lima, Antonio Gilson Barbosa Postgraduate Program in Mechanical Engineering Federal University of Paraíba Paraíba João Pessoa58051-900 Brazil Department of Renewable Energy Engineering Federal University of Paraíba Paraíba João Pessoa58051-900 Brazil Dexco S.A Paraíba João Pessoa58082-797 Brazil Science and Technology Institute Federal University of Jequitinhonha and Mucuri Valleys Minas Gerais Diamantina39100-000 Brazil Department of Mechanical Engineering Federal University of Campina Grande Paraíba Campina Grande58429-900 Brazil

Sanitary ware, including toilets, washbasins, and bathtub, plays a crucial role in maintaining hygiene and sanitation in various settings. The drying process is a critical stage in the manufacturing of ceramic sanitary ware, as it influences product quality, production efficiency, and energy consumption. Then, the purpose of this work is to investigate the drying of sanitary ware at low temperature by experiments and empirical mathematical models. The idea is to accurately predict moisture loss of the ceramic parts under different operational conditions. Results of the drying kinetics have shown that higher temperatures and lower air relative humidity accelerate the drying process. Also, no cracks or fissures were observed as a result of drying sanitary ware at low temperatures and the two-term model provides the best fit for the dimensionless average moisture content as a function of the time. These findings contribute to a better understanding of the drying process and support the optimization of sanitary ware manufacturing. © 2023 Trans Tech Publications Ltd, Switzerland.

关键词： Drying

来源：评论

学校读者我要写书评

暂无评论

Mass transport in a highly immiscible alloy on extended shear deformation

引用

Journal of materials science & Technology 2023年第3期134卷 197-208页

作者： Miao Song Jia Liu Xiaolong Ma Qin Pang Matthew J.Olszta Joshua Silverstein Madhusudhan R.Pallaka Peter V.Sushko Suveen N.Mathaudhu Cynthia Powell Arun Devaraj Bharat Gwalani Physical and Computational Sciences Directorate Pacific Northwest National Laboratory902 Battelle BoulevardRichlandWA 99354USA Energy and Environmental Directorate Pacific Northwest National Laboratory902 Battelle BoulevardRichlandWA 99354USA Material Science and Engineering Program University of CaliforniaRiversideCA92521USA Colorado School of Mines 1500 Illinois St.GoldenCO 8040USA Department of Materials Science and Engineering North Carolina State UniversityRaleighNC27695-7907USA State Key Laboratory of Powder Metallurgy Central South Uni-versityChangsha 410083China

Forced mixing to a single-phase or supersaturated solid solution(SSS)and its prerequisite microstructure evolution in immiscible systems has been a focus of research for fundamental science and practical *** the formation of SSS by shear deformation could enable a material design beyond conventional equilibrium microstructure in immiscible ***,a highly immiscible Cu-50 at.%Cr binary alloy(mixing enthalpy of∼20 kJ mol^(−1))was employed to investigate the microstructure evolution and localized tendencies of SSS during severe shear *** results demonstrate the dislocation mediated microstructural refinement process in each phase of the binary alloy and the mechanisms associated with localized solute supersaturation as a function of shear *** grain refinement in the softer Cu phase occurs owing to the strain localization driving the preferential dynamic *** grain refinement of the Cr phase,however,is enabled by the progressive evolution of grain lamination,splitting,and fragmentation as a function of shear *** solute supersaturation is found to be strongly dependent on the local environments that affect the dislocation activity,including the level of microstructure refinement,the interfacial orientation relationship,the mechanical incompatibility,and the localized preferential phase *** initio simulations confirm that it is more favorable to oxidize Cr than Cu at incoherent Cu/Cr interfaces,limiting the mass transport on an incoherent *** results unveil the mechanism underpinning the non-equilibrium mass transport in immiscible systems upon severe deformation that can be applied to produce immiscible alloys with superior mechanical properties.

关键词： Tribology Immiscible alloys Nanostructures Shear deformation Forced mixing Atom probe

来源：评论

学校读者我要写书评

暂无评论

Raindrop energy-powered autonomous wireless hyetometer based on liquid-solid contact electrification

引用

Microsystems & Nanoengineering 2022年第2期8卷 175-183页

作者： Chaoqun Xu Xianpeng Fu Chengyu Li Guoxu Liu Yuyu Gao Youchao Qi Tianzhao Bu Yuanfen Chen Zhong Lin Wang Chi Zhang Center on Nanoenergy Research School of Physical Science&TechnologySchool of Mechanical EngineeringGuangxi UniversityNanning 530004China CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 101400China School of Nanoscience and Technology University of Chinese Academy of SciencesBeijing 100049China School of Material Science and Engineering Georgia Institute of TechnologyAtlantaGA 30332USA

Triboelectric nanogenerators(TENGs)can directly harvest energy via solid-liquid interface contact electrification,making them very suitable for harvesting raindrop energy and as active rainfall *** technology is promising for realizing a fully self-powered system for autonomous rainfall monitoring combined with energy harvesting/***,we report a raindrop energy-powered autonomous rainfall monitoring and wireless transmission system(R-RMS),in which a raindrop-TENG(R-TENG)array simultaneously serves as a raindrop energy harvester and rainfall *** a rainfall intensity of 71 mm/min,the R-TENG array can generate an average short-circuit current,open-circuit voltage,and maximum output power of 15 pA,1800 V,and 325 pW,*** collected energy can be adjusted to act as a stable 2.5 V direct-current source for the whole system by a power management ***,the R-TENG array acts as a rainfall sensor,in which the output signal can be monitored and the measured data are wirelessly *** a rainfall intensity of 71 mm/min,the R-RMS can be continuously powered and autonomously transmit rainfall data once every 4 *** work has paved the way for raindrop energy-powered wireless hyetometers,which have exhibited broad prospects in unattended weather monitoring,field surveys,and the Internet of Things.

关键词： energy autonomous harvesting

来源：评论

学校读者我要写书评

暂无评论

Effect of brazing and artificial aging on the microstructure and mechanical properties of a high-strength four-layer laminar aluminum alloy

引用

Vacuum 2025年 239卷

作者： Cao, Qi Zhao, Na Xia, Chengdong Zhang, Zhengjin Cheng, Long Zhou, Dejing College of Materials Science and Engineering Central South University Changsha410083 China Yinbang Clad Material Co. Ltd. Wuxi214145 China College of Mechanical Engineering Quzhou University Quzhou324000 China

The lightweight design of power battery thermal management systems remains a critical challenge for new energy vehicles. Conventional aluminum alloys often fail to achieve satisfactory mechanical properties after high-temperature brazing (600 °C). To address this limitation, we developed modified aluminum alloys (6061MOD and 3003MOD) and engineered a four-layer laminar structure (4045/3003MOD/6061MOD/3003MOD) for water-cooled plate applications. The microstructural changes and mechanical behavior of these materials were systematically investigated after high-temperature brazing and subsequent aging treatments. Brazing induced substantial grain growth in the 6061MOD core layer, increasing average grain size from 42.3 μm to 90.1 μm. Optimal mechanical properties were achieved through post-brazing treatment: air cooling followed by 200 °C aging for 2 h. This treatment resulted in a tensile strength of 287.1 MPa and a yield strength of 230.5 MPa, primarily attributed to the fine precipitation of Al-Cu, AlMgSiCu (Q), and Mg2Si reinforcing precipitates. Elemental diffusion analysis revealed Mg penetration depths of 63.7 μm (initial brazing) and 81.9 μm (secondary brazing), with the 3003MOD layer effective blocking of Mg diffusion. This laminated structural design, which integrates components with distinct functional properties, provides an innovative strategy for developing lightweight, high-strength brazed materials while offering critical implications for next-generation vehicle thermal management systems. © 2025

关键词： Aluminum alloys

来源：评论

学校读者我要写书评

暂无评论

Biomimetic surfaces with patterned wettability for improved dehumidification/air condition efficiency 2

Biomimetic surfaces with patterned wettability for improved ...

引用

2nd International Conference on materials Chemistry and Environmental engineering, CONF-MCEE 2022

作者： Fang, Mingjia Tang, Haoyang Ke, Gege Li, Guanying School of Metal Materials Engineering Jiangsu University of Science and Technology of Materials Science and Engineering Jiangsu Zhenjiang212000 China School of Mechanical and Mining Engineering The University of Queensland BrisbaneQLD4072 Australia School of Environmental Science Chemistry Duke Kunshan University Jiangsu Kunshan215316 China Material Science and Engineering University of North Texas DentonTX76201 United States

ISBN: (纸本)9781510657205

Dehumidification has a massive impact on the energy efficiency of the air condition system. Condensation is a common way to achieve dehumidification. However, a certain amount of energy is required for harvesting water from the air through condensation. A hybrid hollow fiber membrane system proves to be effective in lowering the consumption of energy. However, the surfaces with patterned wettability receives inadequate attention despite its potential to achieve energy-efficient dehumidification. This review casts a view on the mechanism of condensation via patterned surfaces, which are normally originated from natural biomimetic surfaces. Then, three kinds of surfaces, including the completely hydrophobic surface, completely hydrophilic surface, and the hybrid surface, is employed to explain the working principles of dehumidification via condensation. Besides, the connection between air conditioning and dehumidification and an application that involves a membrane dehumidification and water harvest system for condensation are introduced. It can be concluded that the patterned surfaces do have potentials that can be adopted to air conditioning, considering its exceptional condensation capability. © 2022 SPIE.

关键词： Condensation

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：