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Temperature and Thermal Stress Distribution for Metal Mold in Squeeze casting Process

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Journal of Materials Science & Technology 2008年第3期24卷 347-350页

作者： c.H.lee S.H.lee Institute of Technology and Science Chung-Ang University

In the squeeze casting process, loaded high pressure （over approximately 200 MPa） and high temperature influence the thermo-mechanical behavior and performance of the used metal mold. Therefore, to safely maintain the metal molds, the thermo-mechanical characteristics （temperature and thermal stress） of metal mold in the squeeze casting must be investigated. In this paper, temperature and thermal stress distribution of steel mold in squeeze casting process were investigated by using a three-dimensional non-steady heat conduction analysis and a three-dimensional thermal elastic-plastic analysis considering temperature-dependent thermophysical and mechanical properties of the steel mold.

关键词： Squeeze casting Steel mold Thermal stress Thermo-Mechanical analysis

Elimination of Quench cracking by controlling Agitation Uniformity

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材料热处理学报 2004年第5期25卷 457-461页

作者： cANALE Lauralice c.F TOTTEN george E Departamento de Materials Automobilistica e Aerondutica da EESC da Universidade de Sao Paulo - USP Sao Carlos SP BrazilPortland State University USA

Uniform agitation of the quenchant is a critically important control parameter in optimizing distortion control and reducing steel cracking. Quenching with ultrasonic agitation or in the presence of electrical and magnetic fields provide uniform agitation leading to improved uniformity of the stress fields within the metal not readily achievable with more traditional agitation methods such as propeller pumps and sprays. These methods provide the additional potential advantage of varying agitation throughout the cooling cycle to achieve a wide range of cooling profiles not readily achievable with quenchants and more traditional agitation systems currently in use.

关键词：热处理淬火裂纹搅拌均匀性超声搅拌

Settling basin design in a constructed wetland using TSS removal efficiency and hydraulic retention time

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Journal of Environmental Sciences 2014年第9期26卷 1791-1796页

作者： Soyoung lee Marla c.Maniquiz-Redillas lee-Hyung Kim Water Environment Research Dept. National Institute of Environmental ResearchHwangyeong-ro 42Seo-guIncheon 404-708Korea Dept.of civil & Envi.Eng'g. Kongju National University275 BudaedongSeobukguCheonanChungnamdo 331-717Korea

Using total suspended solid （TSS） removal efficiency and hydraulic retention time （HRT） as design parameters a design guideline of a settling basin in a constructed wetland （cW） was suggested; as well as management of sediment and particle in the settling basin. The cW was desiEned to treat the piggery wastewater effluent from a wastewater treatment plant during dry days and stonnwater runoff from the surrounding paved area during wet days. The first settling basin （FSB） in the cVV was theoretically designed with a total storage volume （TSV） of 453 ms and HRT of 5.5 hr. The amount of sediment and particles settled at the FSB was high due to the sedimentation and interception of plants in the cVV. Dredging of sediments was performed when the retention rate at the FSB decreased to approximately 80%. Findings showed that the mean flow rate was 21.8 m3/hr less than the designed flow rate of 82.8 m3/hr indicating that the FSB was oversize and operated with longer HRT （20.7 hr） compared to the design HRT. An empirical model to estimate the length of the settling basin in the cW was developed as a function of HRT and desired TSS removal efficiency. Using the minimum tolerable TSS removal efficiency of 30%, the length of the FSB was estimated to be 31.2 m with 11.8 hr HRT.

关键词： constructed wetlandHydraulic retention timeParticle size distributionSettling basin designTSS removal efficiency

Effects of interlayer spacing and applied pressure on the lanthanide transport in MoS_(2)-based two-dimensional channels

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International Journal of Smart and Nano Materials 2024年第3期15卷 579-592页

作者： Qinsi Xiong chong Liu george c.Schatz Department of chemistry Northwestern UniversityEvanstonILUSA Pritzker School of Molecular Engineering University of ChicagoChicagoILUSA

Rare-earth elements(REEs)are critical to modern industry but difficult to separate due to their subtle and monotonic changes in physico-chemical ***2-based two-dimensional(2D)materials offer novel opportunities for enhancing REE separation,exhibiting a distinct volcano-shaped transport performance distribution that peaks at Sm3+.However,the specific contributions of thermodynamic and kinetic factors to ion transport within 2D confinement remain *** this study,we conducted a series of non-equilibrium all-atom molecular dynamics(MD)simulations to explore the effects of interlayer spacing and external pressure on the transport of lanthanide ions inÅ-scale acetate functionalized 2D MoS2(MoS2-cOOH)*** examined ion entry and permeation rates,water flux,dehydration,and binding *** simulation results reveal that the transport trends of lanthanide ions are jointly driven by the dehydration degree and the relative-binding strengths of ions to water and to the acetate within the 2D ***,the dehydration pattern of lanthanide ions during permeation is closely linked to kinetic ***,this study provides a detailed atomistic understanding of the mechanisms under-lying lanthanide ion transport under *** findings point to the significant potential for tuning confinement and chemical functionalization withinÅ-scale channels for more efficient REE separation.

关键词： MoS_(2) 2D channels Lanthanide ions ion transport nanofluidics

Male courtship signal modality and female mate preference in the wolf spider Schizocosa ocreata: results of digital multimodal playback studies

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current Zoology 2019年第6期65卷 705-711页

作者： Elizabeth c.KOZAK george W.UETZ Department of Biological Sciences University of CincinnatiCincinnatiOHP.0.Box 260006USA45221-0006

Females must be able to perceive and assess male signals,especially when they occur simultaneously with those of other *** studies show female Schizocosa ocreata wolf spiders display receptivity to isolated visual or vibratory courtship signals,but increased receptivity to multimodal *** is unknown whether this is true when females are presented with a choice between simultaneous multimodal and isolated unimodal male *** used digital playback to present females with a choice simulating simultaneous male courtship in different sensory modes without variation in information content:1)isolated unimodal visual versus vibratory signals;2)multimodal versus vibratory signals;and 3)multimodal versus visual *** choosing between isolated unimodal signals(visual or vibratory),there were no significant differences in orientation latency and number of orientations,approaches or receptive displays directed to either *** given a choice between multimodal versus vibratory-only male courtship signals,females were more likely to orient to the multimodal stimulus,and directed significantly more orients,approaches and receptivity behaviors to the multimodal *** presented with a choice between multimodal and visual-only signals,there were significantly more orients and approaches to the multimodal signal,but no significant difference in female *** suggest that signal modes are redundant and equivalent in terms of qualitative responses,but when combined,multimodal signals quantitatively enhance detection and/or *** study confirms the value of testing preference behavior using a choice paradigm,as female preferences may depend on the context(e.g.,environmental context and social context)in which they are presented with male signals.

关键词： mate choice multimodal communication Schizocosa signaling wolf spider

Developing Skin Analogues for a Robotic Octopus

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Journal of Bionic Engineering 2012年第3期9卷 385-390页

作者： Jinping Hou Richard H. c. Bonser george Jeronimidis centre for Biomimetics School of Construction Management and Engineering University of Reading Reading RG6 6AY UK School of Engineering and Design Brunel University Uxbridge Middlesex UB8 3PH UK

In order to fabricate a biomimetic skin for an octopus inspired robot, a new process was developed based on mechanical properties measured from real octopus skin. Various knitted nylon textiles were tested and the one of 10-denier nylon was chosen as reinforcement. A combination of Ecoflex 0030 and 0010 silicone rubbers was used as matrix of the composite to obtain the right stiffness for the skin-analogue system. The open mould fabrication process developed allows air bubble to escape easily and the artificial skin produced was thin and waterproof. Material properties of the biomimetic skin were char- acterised using static tensile and instrumented scissors cutting tests. The Young＇s moduli of the artificial skin are 0.08 MPa and 0.13 MPa in the longitudinal and transverse directions, which are much lower than those of the octopus skin. The strength and fracture toughness of the artificial skin, on the other hand are higher than those of real octopus skins. conically-shaped skin prototypes to be used to cover the robotic arm unit were manufactured and tested. The biomimetic skin prototype was stiff enough to maintain it conical shape when filled with water. The driving force for elongation was reduced significantly compared with previous prototypes.

关键词： biomimetic skin artefact octopus robot textile composite

AN AccURATE TWO-DIMENSIONAL THEORY OF VIBRATIONS OF ISOTROPIc,ELASTIc PLATES

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Acta Mechanica Solida Sinica 2011年第2期24卷 125-134页

作者： Peter c.Y.lee Department of civil and Environmental Engineering Princeton University

An infinite system of two-dimensional equations of motion of isotropic elastic plates with edge and corner conditions are deduced from the three-dimensional equations of elasticity by expansion of displacements in a series of trigonometrical functions and a linear function of the thickness coordinate of the plate. The linear term in the expansion is to accommodate the in-plane displacements induced by the rotation of the plate normal in low-frequency flexural motions. A system of first-order equations of flexural motions and accompanying boundary conditions are extracted from the infinite system. It is shown that the present system of equations is equivalent to the Mindlin＇s first-order equations, and the dispersion relation of straight-crested waves of the present theory is identical to that of the Mindlin＇s without introducing any corrections. Reduction of present equations and boundary conditions to those of classical plate theories of flexural motions is also presented.

关键词： isotropic elastic plates first-order equations boundary conditions flexural andthickness-shear vibrations

Design of a Biomimetic Skin for an Octopus-Inspired Robot - Part Ⅱ： Development of the Skin Artefact

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Journal of Bionic Engineering 2011年第3期8卷 297-304页

作者： Jinping Hou Richard H. c. Bonser george Jeronimidis centre for Biomimetics School of Construction Management and Engineering UniversiO~ of Reading Reading RG6 6A Y UK

In order to develop skin artefact for an octopus-inspired robot arm, which is designed to be able to elongate 60% of its original length, silicone nlbber and knitted nylon sheet were selected to manufacture an artificial skin, due to their higher elastic strain and high flexibility. Tensile and scissors cutting tests were conducted to characterise the matrix and reinforcing materials and the skin artefact. Material properties of the individual and the composite materials were compared with the measured properties of real octopus skin presented ill Part I. The Young＇s modulus of the skin should be below 20 MPa and the elastic strain range should be over 60%. The fracture toughness should be at least 0.9 kJ.m 2. Tubes made of the skin artefact filled with liquid were tested to study volume change under deformation. Finite element analysis model was developed to simulate the material and arm structure under tensile loading. Results show that the skin artefact developed has similar mechanical properties as the real octopus skin and satisfies all the design specifications of the OcTOPUS robot.

关键词： octopus skin static tensile test toughness skin artefact nylon/silicone composite

Design of a Biomimetic Skin for an Octopus-Inspired Robot - Part I： characterising Octopus Skin

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Journal of Bionic Engineering 2011年第3期8卷 288-296页

作者： Jinping Hou Richard H. c. Bonser george Jeronimidis centre for Biomimetics School of Construction Management and Engineering University of Reading Reading RG6 6AY UK

Octopus skin samples were tested under quasi-static and scissor cutting conditions to measure the in-plane material prop- erties and fracture toughness. Samples from all eight arms of one octopus were tested statically to investigate how properties vary from arm to arm. Another nine octopus skins were measured to study the influence of body mass on skin properties. In- fluence of specimen location on skin mechanical properties was also studied. Material properties of skin, i.e. the Young＇s modulus, ultimate stress, failure strain and fracture toughness have been plotted against the position of skin along the length of arm or body. Statistical studies were carried out to help analyzing experimental data obtained. Results of this work will be used as guidelines for the design and development of artificial skins for an octopus-inspired robot.

关键词： octopus skin uniaxial tension scissor cutting Young's modulus failure strain fracture toughness