bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiferroic and Piezoelectric Behavior of Transition-Metal Doped ZnO Films
Authors: Pan Feng , Liu Xue Jing , Yang Yu Chao , Song Cheng , Zeng Fei
Published: August 2009

In this paper, we report the multiferroic and piezoelectric behavior observed in transition-metal doped ZnO films. The experimental results indicated that the Co-doped ZnO films deposited by magnetron sputtering possess a Curie temperature higher than 700K, and the magnetic moments of Co are intimatedly correlated to the doping concentration and the substrate. A giant magnetic moment of 6.1 B/Co is observed in (4 at.%) Co-doped ZnO films. Ferroelectric and ferromagnetic behaviors simultaneously were also obtained in V and Cr doped ZnO films on Pt(111)/Ti/SiO2/Si(100) substrates by reactive sputtering method, revealing a multiferroic nature. The high piezoelectric d33 coefficient 80-120 pm/V has also been achieved by Cr and V substitutions, which could make Cr-doped or V-doped ZnO a promising material in piezoelectric devices.
Preparation and Properties Fluoralkylpolysiloxane Modified Polyurethane Films
Authors: Weng Rui , Wang Chong Rui , Zhang Lian Meng , Wang Shui Ping
Published: August 2009

Fluoralkylpolysiloxane modified Polyurethane (FSPU) films with high water contact angle (CA) were prepared. fluoralkylpolysiloxane was obtained using perfluoro octyl sulfuryl fluoride and terminal amino-silicone oil as reactants. Then, the isocyanate end capped PU prepolymer was synthesized by reacting isocyanate with a soft segment mixed by active amino-end-capping fluoralkylpolysiloxane and polyether glycol. The fluoralkylpolysiloxane modified PU films were obtained after the PU prepolymer was cured by 3,3 '- dichloro -4,4' – amino - diphenyl methane (MOCA). The results showed that the modified polyurethane with 10% (mass fraction) PFATPS had a good compatibility, low surface energy, surface water contact angle and surface oil contact angle was improved by 49° and 37° respectively, and heat resistance, water resistance was apparently improved.
Preparation of Bioactive Porous Titanium-Molybdenum Alloy through Powder Metallurgy
Authors: Yamada Yasuo , Li Yun Cang , Xiong Jian Yu , Banno Takumi , Hodgson Peter  D. , Wen Cui E
Published: August 2009

Porous Ti-Mo alloy samples with different porosities from 52% to 72% were successfully fabricated by the space-holder sintering method. The pore size of the porous Ti-Mo alloy samples were ranged from 200 to 500 μm. The plateau stress and elastic modulus of the porous Ti-Mo alloy samples increases with the decreasing of the porosity. Moreover, an apatite coating on the Ti-Mo alloy after an alkali and heat treatment was obtained through soaking into a simulated body fluid (SBF). The porous Ti-Mo alloy provides promising potential for new implant materials with new bone tissue ingrowth ability, bioactivity and mechanical properties mimicking those of natural bone.
Research on Physical and Mechanic Properties of Green-Growing Porous Concrete for Ecological Slope Protection
Authors: Xiong Xiao Bo , Gui Guo Qing , Zhao Qi Hua
Published: August 2009

In this paper, the conception and classification of Green-growing porous concrete (POC) is introduced. POC is made of single-sized coarse aggregate, Portland cement, admixtures, chemical admixtures, water, et al. It should be properly mixed before cast in mould. Because of its large-pore structure, POC have much ecological and environmental value. In the case of be used as greening concrete which placed in highway side, POC’s compressive strength should be higher than 15MPa, at the same time, its valid porosity content should be at the range of 25% and 30%.
Porous Silicon Nitride Ceramics Prepared by Reduction – Nitridation of Diatomite
Authors: Xue Yao Hui , Lu Yuan , Wang Bo , Yang Jian Feng , Lu Wei Zhong , Gao Ji Qiang
Published: August 2009

In this paper, porous Si3N4 ceramics were fabricated by carbothermal reduction between carbon black and diatomite. Diatomite is a siliceous, sedimentary rock consisting principally of the fossilized skeletal remains of diatom, a unicellular aquatic plant related to the algae. The main ingredient of diatomite is the amorphous active silicon dioxide. The influence of diatomite particle size on the microstructure of sintering bodies was analyzed. XRD analysis demonstrated the formation of Si3N4 except for minor of glass phase. SEM analysis showed that the resultant porous β-Si3N4 ceramics occupied fine microstructure and uniform pore structure.
Structure Change and Improvement of the Mechanical Properties of Lotus-Type Porous Copper by ECAE Process
Authors: Lobos Juan , Suzuki Shinsuke , Utsunomiya Hiroshi , Nakajima Hideo
Published: August 2009

Deformation behavior of lotus-type porous copper with long cylindrical pores aligned in one direction through equal-channel angular extrusion (ECAE) process was investigated using a die with channel angle of 150º. Although the density slightly increased after every pass, the porous structure remains in the process. The Vickers hardness and the compressive yield strength of lotus copper increased through the ECAE process. The compressive yield strength after 3 passes increased up to 10 times larger than that before processing. The deformation of lotus copper takes place by buckling and the shearing of the cell walls. The increase in hardness is considered to be caused by work hardening.
Fabrication and Properties of Pressureless Sintered Si3N4/BN Composite Ceramics with La2O3-Al2O3-Y2O3 as Sintering Additives
Authors: Li Yong Feng , Liu Ping , Qiao Guan Jun , Yang Jian Feng , Jin Hai Yun , Wang Xiang Dong
Published: August 2009

With commercial α-Si3N4 and h-BN powders as starting materials, La2O3, Al2O3, Y2O3 as sintering additives, Si3N4/BN composite ceramics with 25vol% h-BN were fabricated by pressureless sintering. Various amounts of La2O3 (0, 2, 4, 8, 15wt%) were added, with constant Y2O3/Al2O3 weight ratio and additives (Y2O3/Al2O3/La2O3) amount. The densification behaviors, α-βtransformation and room-temperature strength of Si3N4/BN composite were investigated. The porosity of samples decreased with La2O3 content increasing, and the lowest porosity of 20.83% was observed for samples containing 4wt% La2O3, then leaded to an increase. The flexural strength of all the specimens increased with the addition up to 4wt% and changed greatly thereafter. The highest room-temperature flexural strength, 272.4MPa, was obtained when 4wt% La2O3 was added. Results of XRD patterns revealed that β-Si3N4 and h-BN existed in all the specimens. No α-Si3N4 was detected, implying thatα- toβ-Si3N4 transformation has been completed during the pressureless sintering process. These results show that the La2O3-Al2O3-Y2O3 system can act as effective sintering additives for pressureless sintered Si3N4/BN composite.
Porous Materials with Hybrid Structure Produced by Nitriding Partially-Sintered Silicon
Authors: Nanko Makoto
Published: August 2009

New porous materials with hybrid pore structure “Fibers-In-Pores” structure were produced by developing Si3N4 whiskers in pores of partially-sintered silicon by nitriding. Because silicon and Si3N4 have excellent heat resistance, the proposed porous materials are expected to utilize high-temperature applications such as gas filters. Porous silicon was produced by sintering Si powder at 1300°C for 1 h in a stream of Ar gas. Porous Si bodies were nitrided at 1300°C for 1 h with N2 gas to develop long Si3N4 whiskers in pores of partially-sintered silicon. Specific surface area was increased and gas permeability was decreased by applying the nitridation process at 1300°C.
Abrasive Grain Efficiency and Surface Roughness in Machining Magnesium Alloys by Newly Developed Cup-Type Diamond-Grinding-Wheels
Authors: Nguyen Tien Dong , Matsumaru Koji , Takatsu Masakazu , Ishizaki Kozo
Published: August 2009

New cup-type diamond-grinding-wheels with hexagonal pattern have been developed. Grinding stone ratio, R is defined as the ratio between the hexagonal edge area containing abrasive grains and the total area of the wheel surface. In the present work, four kinds of hexagonal grinding wheels with different R (13 %, 19 %, 25 % and 36 %) and a conventional wheel (R: 100 %) were used to grind a light metals, which was represented by magnesium alloy AZ31B. Efficiency of abrasive grains and ground surface for machining a light metals were evaluated by calculating the number of abrasive grains which pass through a unit length of a sample surface for each grinding pass, Ng.
The results show that surface roughness becomes smaller, i. e., smoother surfaces as Ng increases. Surfaces ground by the conventional wheel are rougher than those by using newly developed hexagonal grinding-wheels in spite of the larger Ng for the conventional wheel. Surface roughness data forms one curve in roughness vs. Ng graph for all hexagonal wheels, and forms another curve for the conventional grinding-wheel.
The difference of two curves indicates that the number of effective working abrasive grains in hexagonal wheels is about 5 times higher than that of the conventional wheel. The similar results were obtained for machining sapphire according to our previous work. Hexagonal wheels show higher abrasive grain efficiency for machining not only hard-to-machine ceramics but also light metals such as magnesium alloys than conventional wheels.
A Novel Method for the Preparation of Porous SiC
Authors: Liu Rong Zhen , Wang Bo , Cheng Ji Kuan , Yang Jian Feng , Gao Ji Qiang
Published: August 2009

A novel method for preparing porous silicon carbide ceramics with high porosity had been developed by recrystallization of green bodies composed of α-SiC, β-SiC, remnant silicon and incompletely-reacted carbon. Fine microstructure and uniform pore structure of the resultant porous silicon carbide ceramics was obtained. The green bodies of porous ceramics were prepared by the precursor powder which contained α-SiC, carbon black and silicon powder. The precursor powder was sintered at 1600°C under Vacuum circumstance to obtain the green bodies; the sintering process is same with the reaction sintering silicon carbide. Then the green bodies were sintered to 2300°C for half an hour to recrystallization. The incompletely-reacted carbon was fully reacted with silicon. And the remnant silicon was excluded during the recrystallization process to create porous structures. The influence of composition of the precursor powder and the fabrication process (the moulding pressure) on the microstructure of sintering bodies was analyzed. X-ray diffractometry demonstrated the transformation of β-SiC to α-SiC during the recrystallization process. The density and the porosity of this material was 1.027g/cm3 and 67% respectively.
Fabrication of Clay Foam Ceramics Using Silicon Carbide and Ferric Oxide as Foaming Agents
Authors: Liu Guang Liang , Bai Jian Guang , Yang Jian Feng
Published: August 2009

In this paper a foam ceramic was prepared from clay, silicon carbide, ferric oxide, feldspar and other raw materials. The content of ferric oxide and the powder size of silicon carbide influenced the sinter behavior of the foam ceramics. The ferric oxide and feldspar are favorable to form of glass phase in the ceramics. The foam ceramics with the rate of moisture absorption is less than 0.05%, the bulk density is 0.3~0.9g/cm3, and compressive strength is over than 2MPa.
Fabrication of Porous Metals with Directional Pores through Solidification of Gas-Dissolved Melt
Authors: Nakajima Hideo , Ide Takuya , Kim Song Youl
Published: August 2009

Porous metals with long cylindrical pores aligned in one direction were fabricated by unidirectional solidification using pressurized gas (hydrogen) method (PGM) and thermal decomposition method (TDM). The pores are evolved from insoluble gas when the molten metal dissolving the gas is solidified. In the conventional PGM, the hydrogen pressurized in a high-pressure chamber is used as the dissolving gas. However, the use of high-pressure hydrogen is not desirable because of inflammable and explosive gas, in particular, for scaling up to mass production of lotus metals. In order to overcome this shortcoming, the thermal decomposition method was developed as an alternative simple fabrication method. Gas-forming compounds were added into the molten metal to fabricate lotus metals. The porosity and pore size were controlled by the amount of gas-forming compounds. TDM was applied to fabricate porous copper and aluminium
Geopolymer Concrete Fabricated by Waste Concrete Sludge with Silica Fume
Authors: Yang Z. X. , Ha N. R. , Jang M.S. , Hwang Kyu Hong
Published: August 2009

As a relatively new material, geopolymer concrete offers the benefits as a construction material for sustainable development. It utilized waste materials such as recycled concrete sludge, fly ash and etc. It has a very low rate of green house gas emission when compared to ordinary Portland cement. In this study, the component of geopolymer is concrete sludge, metakaolin and water glass, NaOH was used as alkalin activator. To improve the mechanical properties, the amount of NaOH and water glass were varied to obtain higher strength and the specimens were cured both in air and water, then their mechanical properties like compressive strength and bending strength were measured the microstructures were investigated.
Synthesis and Microstructural Control of In2O3(ZnO)3 Layered Compound by Microwave-Heating
Authors: Yanagiya Shouhei , Hayashi Yamato , Takizawa Hirotsugu
Published: August 2009

In2O3(ZnO)3 layered compound was synthesized by 2.45 GHz microwave heating in a solid state reaction. Microwave-processed samples were obtained at low temperature by the enhancement of solid state diffusion and sublimation of the powder bed. Plate-like grain microstructures formed on the bottom part of the pellet, and vicinity of the surface was dense. The plate-like grain was oriented in the ab-plane direction. Compared with a conventional heated sample, the electrical conductivity increased and the band gap energy decreased. In the case of deposition on a silica substrate by microwave heating, the plate-like grain film was synthesized.
Eco-Friendly Grain Refinement for A3003 Alloy
Authors: Cho Hoon , Ha Jae Hong , Lee Byoung Soo , Chang Sung Ho , Shin Je Sik
Published: August 2009

Eco-friendly grain refinement of A3003 alloy was studied by addition of non-toxic Al-Ti alloy because of toxic-fluorine in Al-Ti-B alloys which used as a representative grain refiner for aluminum and its alloys. TiAl3 phase in Al-Ti alloy bring to decrease grain size of A3003 alloy. But, grain growth occurred with prolonged holding time due to the solution of Ti into aluminum matrix. In contrast, lasting grain refinement of A3003 alloy was occurred in graphite crucible. It can be mentioned that carbon comes from graphite crucible was combined with Ti solute in aluminum melt and then TiC acts as a heterogeneous nucleation for A3003 alloy.
Evaluations of Hydrogen Properties on MgHx-Nb2O5 Composite by Mechanical Alloying
Authors: Kim Kyeong Il , Hong Tae Whan
Published: August 2009

The most attractive way to storage hydrogen safely and economically is in metal hydrides. In particular, magnesium has attracted much interest since their hydrogen capacity exceeds that of known metal hydrides. One of the approaches to improve the kinetic is addition of metal oxide. In this paper, we tried to improve the hydrogen absorption properties of Mg. The effect of transition oxides, such as Nb2O5 on the kinetics of the Mg hydrogen absorption reaction was investigated. MgHx-Nb2O5 composites have been synthesized by hydrogen induced mechanical alloying. The powder synthesized was characterized by XRD, SEM, EDX, BET and simultaneous TG/DSC analysis. The hydrogenation behaviors were evaluated by using an automatic Sievert’s type PCT apparatus. Absorption/desorption kinetics and PCI of MgHx catalyzed with 5wt.%Nb2O5(as-received), 5wt.%Nb2O5(30min. milled) are determined at 423, 473, 523, 573, 623K.
Studies on Filming of Corn Starch
Authors: Chen Zhi Zhou , Wang Jian Qing
Published: August 2009

In this study, corn starch was taken as the raw material and its filming property was studied through single-factor experiments and orthogonal experiment. The results showed that there were significant effects on properties of the corn starch films under different corn starch concentration, glycerol concentration, CMC-Na concentration and pH value of coating liquid. Referring to the effects on properties of corn starch films, the most important factor was the glycerol concentration, the following factors were the pH value of the coating liquid, the CMC-Na concentration and the corn starch concentration. The optimum filming condition was 5.5% corn starch, 1.0% glycerol, 0.15% CMC-Na and pH 6.0-6.9 for the coating liquid of film-forming.
The Strain Rate Intensity Factor and its Applications: A Review
Authors: Alexandrov Sergei
Published: August 2009

The present paper concerns with the concept of the strain rate intensity factor in rigid plastic solids. The strain rate intensity factor is the coefficient of the principal singular term in the expansion of the equivalent strain rate in a series in the vicinity of maximum friction surfaces. Such singular velocity fields appear in solutions based on several rigid plastic models. Because of this singularity in the velocity field, many conventional evolution equations for material properties are not compatible with such rigid plastic solutions. On the other hand, qualitative behaviour of the singular rigid plastic solutions in the vicinity of maximum friction surfaces is in agreement with a number of experimental results. Therefore, the primary objective of research in this direction is to develop an approach to relate parameters of the singular velocity fields and parameters characterizing material properties. The approaches proposed in previous works are based on the strain rate intensity factor. In the case of analytical and semi-analytical solutions the strain rate intensity factor can be found by means of an asymptotic analysis of the solutions. A number of such solutions obtained by inverse methods are reviewed in the present paper and the strain rate intensity factor is found. An effect of process parameters on its magnitude is shown and discussed.
Preliminary Design of a Composite Material Flywheel
Authors: Alexandrova Nelli N. , Vila Real Paulo M.M.
Published: August 2009

Flywheel rotor performance monitoring and damage detection are increasingly gaining the interest of manufacturers of aircraft engines. This is primary due to the fact that there is a necessity for improving safety during operation as well as a need for lower maintenance costs. Applied techniques for damage detection and health monitoring of rotors are essential for engine safety, reliability and life prediction. Preliminary design of such a flywheel studied here is based on a simple model of annular rotating disk with stress-free boundary conditions. In addition to the critical rotational speed, the paper analyses the influence of the leading design parameter - material plastic anisotropy - on the development of plastic zone and stress/strain distributions.
Experimental Investigations and Numerical Analysis for Improving Knowledge of Incremental Sheet Forming Process for Sheet Metal Parts
Authors: Dejardin Steeve , Gelin Jean Claude , Thibaud Sebastien
Published: August 2009

The paper is related to the analysis of shape distortions and springback effects arising in Single Point Incremental Forming. An experimental set up has been designed and manufactured to carry single point incremental forming on small size sheet metal parts. The experimental set up is mounted on 3-axes CNC milling machine tool and the forming tool is attached and move with the spindle. Experiments have been carried out on sheet metal parts to obtain tronconical shapes. The forming strategy associated to the movement of the forming tool has been also investigated. The experiments indicate that shape distortions arising in the corners of the tronconical shape are clearly related to forming strategy. The springback of rings cut in the tronconical parts have been also investigated. It is shown that positive or negative springback could be also related to forming strategy. In order to enhance experimental investigations, Finite Element simulations of the incremental sheet forming have been performed. Results obtained from the simulations prove that if boundary conditions and forming strategy carefully are taking into account, the finite elements results are in good agreement with experiments. So it is then possible to use FEM as a design tool for incremental sheet forming.
Modelling Dense Granular Flows
Authors: Harris David
Published: August 2009

In this paper we discuss properties of dense granular °ows and elaborate on some
properties of a model which generalises the classical plastic potential model using elements of
the double shearing model. It is shown how the model is embedded into a Cosserat continuum
model. The proposed model recti¯es the ill-posedness of both the non-associated °ow rule and
the double shearing model and may be used for both granular materials and also for metals
which possess a micro-structure which is capable of rotation.
An Upper Bound Solution for Upsetting of Anisotropic Hollow Cylinders
Authors: Lyamina Elena , Tzou Gow Yi , Hsia Shao Yi
Published: August 2009

The paper concerns with an effect of plastic anisotropy on the load required to deform hollow cylinders between two parallel, rough dies. It is assumed that the material obeys Hill’s quadratic yield criterion and its associated flow rule. The friction stress is supposed to be proportional to the corresponding shear yield stress, including the maximum friction law as a special case. The kinematically admissible velocity field is chosen such that the stress field following from the associated flow rule satisfies the boundary condition at the plane of symmetry. Moreover, this velocity field is singular in the vicinity of the friction surface. Therefore, in the case of the maximum friction law the friction law is satisfied, again if the associated flow rule is combined with the velocity field. A significant effect of plastic anisotropy on the limit load is illustrated.
FE Analysis of Size Effect on Deformation Behavior of Metal Microtube Considering Surface Roughness in Flaring Test
Authors: Mirzai Mohammad Ali , Manabe Kenichi
Published: August 2009

Reliable test results that show the material characteristics of a micromaterial are necessary for the accurate analysis and design of microforming processes. The size effects in the microforming are predicted to have a significant impact on the material behavior. Two size effects are explored in metallic materials. One is the grain size effect, and the other is the feature/specimen size effect. In this study, the feature size effect on the smoothing process with the consideration of tool surface roughness is investigated numerically for metal microtubes by the flaring test. Stainless-steel (SUS 316L) microtubes with the same outer diameter of 500 μm and different wall thicknesses of 50, 25 and 10 μm were used in the FE analysis to study the feature size effect on the microscale by the flaring test. The surface roughnesses of the inner and outer surfaces of the microtube, as well as the surface asperity of the conical tool, were modeled in the cyclic concave-convex configuration. It is found, in the flaring test with using rough and fine tools, that the smoothing process on the inner surface of the microtube (ISM), as well as the plastic strain in the wall thickness of microtube, is affected owing to the rigidity of the microtube, which decreases as the wall thickness of the microtube decreases. These results suggest that the feature size affects the flaring test results for the metal microtube.
Plane-Strain Compression of a Three Layer Strip Containing Viscoplastic Material with Saturation Stress
Authors: Miszuris Wiktoria
Published: August 2009

The plane strain compression of a long symmetric strip consisted of a three layer material between rigid, parallel, rough plates is under consideration. Two possible geometrical configurations of the layers are examined (a) a viscoplastic material is situated between two layers consisting of a rigid/perfectly plastic material, (b) a rigid/perfectly plastic material lies between two viscoplastic layers. It is assumed throughout the paper that the viscoplastic law is bounded in that sense that it reaches its critical value (saturation stress) as the strain rate tends to infinity. Exploiting closed form solutions obtained, qualitative differences between them and the known from literature solutions for three layer material structure with classic viscoplastic material are discussed. Asymptotic behaviour of solutions in the vicinity of maximum friction surfaces is analysed for any configuration.
Quantitative Analysis of Microstructure and Modeling of Sintering
Authors: Chaix Jean Marc
Published: August 2009

Microstructure is the key scale to understand and describe sintering mechanisms and their consequences at the macroscopic level. As modeling techniques are continuously developing, the need for input data and comparison with more and more accurate descriptions of the evolution is expected to create a growing demand for quantitative microstructure data. Image analysis is the classic way to get these data. This paper reviews the practical use and progresses of this old technique in the sintering literature during the past and recent years. The place of basic tools and more recent ones, such as 3D imaging, are discussed from a practical point of view accounting from sintering models needs: mean size and size distributions in pores and grains, homogeneity, sintering trajectories…
Doped LaGaO3 Based Solid Oxide Fuel Cell Materials and their Sintering Aspects: An Overview
Authors: Datta Pradyot
Published: August 2009

Solid oxide fuel cells (SOFCs) are electrochemical devices that offer advantages over conventional power generation systems in terms of their high efficiency of power generation, low emission of green house gases and the flexibility of fuel usage. The major research focus of recent times is to lower the operating temperature of SOFC in the range of 600 to 800°C so as to make it commercially viable. This reduction in temperature is largely dependent on finding an electrolyte material with adequate oxygen ion conductivity at the intended operating temperature. One much material is pervoskite LaGaO3 doped with Sr- and Mg- La1-xSrxGa1-yMgyO3-δ (LSGM) that shows very good oxygen ion conductivity at intermediate temperature (600-800°C) over a wide range of oxygen partial pressure. The aim of this overview is to highlight the contribution that materials chemistry has made to the development of LSGM based SOFCs.
Computer Simulation of Liquid Phase Sintering: Gravity Induced Skeletal Structure Evolution – A Review
Authors: Nikolic Zoran S.
Published: August 2009

This paper summarizes and reviews a number of important theoretical and experimental results connected to study of gravitational effects on liquid phase sintering. However, we will also investigate numerically gravity induced skeletal structure evolution during liquid phase sintering. Applying domain methodology, solid skeleton evolution will be introduced by definition of skeleton units determined by equilibrium dihedral angle and formation of large solid skeleton arranged in long chain of connected solid-phase domains. The settling procedure will be simulated by two submodels: free settling model in which solid-phase domains fall under gravity over already settled domains, and extended model in which settled domains continue their motion till they reach a position of their local equilibrium. Three more submodels will be also defined: rearrangement densification model, settling densification model, and Brownian motion model. It will be assumed that under gravity condition Stokes’s law settling usually dominates microstructure formation, where the settling procedure as well as settling time will be used for computation of average migration distance during defined time interval. Thus gravity induced solid-phase domain structure evolution will be simulated by simultaneous computation of displacement of the center of mass. The new methodology will be applied for simulation of microstructural evolution of a regular multi-domain model under gravity and gravity conditions.
An Integrated Approach to Teach Metal Forming and Moulding as per New EHEA Framework
Authors: Sánchez Jose Antonio , López de Lacalle Luis Norberto , Ortega N. , Lamikiz Aitzol , Plaza Soraya
Published: August 2009

The paradigm the new European Higher Education Area places us in together with the teaching/learning guidelines and models demands the teacher adapt his/her function considering new methods which locate the students in the centre of this process. In this context the experience of the subject ‘Advanced forming and moulding techniques’ taught in 5th course of the Industrial Engineering qualification at the Bilbao Engineering Faculty (UPV/EHU), is presented. This subject must be taken by students opting for intensification in Mechanical Manufacturing. The subject is taught over tour months with 30 students per group on average, where a methodology based on Scoring Rubrics was set up.
The Application of PDAs and Smartphones in the Classroom as Instruments for Improvement of Learning Monitoring
Authors: Estrems Manuel , Cerdán Fernando , García Diego , Sánchez Horacio T. , Franco Patricio
Published: August 2009

The skill of students in the use of new technologies could provoke serious problems of lower attention toward studied contents in the classroom. Nevertheless, many advantages can be also highlighted from an educational point of view: high ability for the search of technical information, quicker exchange of information by keyboard interface, good communication resources for group works, etc. In this sense, the quality of teaching action can be remarkably improved by the application of educational platforms based on electronic devices such as PDA and Smartphones, as proved by the project of educative innovation that was carried out by the authors of this work. With the purpose of promoting the philosophy of continuous improvement into the teaching/learning process, these authors created a platform dedicated to facilitate the interactive communication between teacher and students inside the classroom, as a useful educative tool to provide a feedback about learning level achieved by students. The new technology is oriented to assist to the teacher by means of introduction of the Shewhart Cycle –or also named PDCA (Plan, Do, Check, Act) Cycle–, avoiding the waste of sheet and significant time losses during the educative practice. The results obtained regarding the course “Quality Engineering” that belongs to degree of Industrial Engineering are shown in this work, although similar benefits could be achieved for other courses contained in technical teachings.
CAL-CBT Based Virtual Learning and Training in Machining Engineering. A Case Study: CNC Lathe
Authors: Batista Moisés , Álvarez Miguel , Sánchez-Carrilero Manuel , Salguero Jorge , Marcos Bárcena Mariano
Published: August 2009

Computer-Aided Learning is currently applied for improving educational methods in order to reach teaching objectives in experimental fields, which are in a continuous renovation process. So, handling new machines learning cannot be usually carried out in Teaching Centres because of the high economical inversion required. Furthermore, the number of students / number of machines ratio is too high. This acquires special relevance in technical studies where practical learning is essential.
In this work, a virtual learning and training application for a CNC lathe is presented into a virtual learning environment developed in the Manufacturing Engineering Labs of the University of Cadiz.
Computer Aided Practical Teaching of the Electro Discharge Machining Process
Authors: Diéguez Jose L. , Araújo G. , Ares E. , Pereira A. , Pérez J.A. , Peláez G.
Published: August 2009

With the necessity to improve the teaching techniques of the processing technologies, in the present paper is showed the development and implantation of a application software that will serve to aid the student of the electro discharge machining process in the decision making process planning this non-conventional manufacture method. This application software manages the totality of the electro discharge machining process, in the die sinking case, by means of the creation of a data base with the necessary parameters of machining. To do these specific tasks, this application makes the data acquisition in analytical form of the machining values that the student tries to reach and has also a graphical environment form to define the geometry of the wished cavity. Finally it exposes the results in a didactic form expressed in a sheet of manufacture operations..
Good Practices in Teaching of Advanced Processes in Mechanical Engineering Projects Learning Groups
Authors: Ares E. , Diéguez Jose L. , Hernández P. , Pereira A. , Pérez J.A. , Peláez G.
Published: August 2009

It has developed a methodology to implement the Project Group Based Learning (PGBL) to solve the problems associated with the introduction of an innovative process conditioned by different types of restrictions, both the structure and type of curriculum, teaching resources available. This paper describes the characteristics of the experiences in PGBL in class practices related Technologies and Manufacturing Processes in ETSII of Vigo, as a part of changing habits and methods based on educational experiences which occurs in different countries of the European Area of Higher Education. We can conclude that the PGBL is a good alternative to the traditional education, especially to address and solve the real problems that require application of knowledge in Mechanical Manufacturing.
New Virtual Environment for Active Learning on Parameter Adjustment of Plastic Injection Molding
Authors: Marquez J.J. , Rodriguez M. , Martinez M.L. , Perez J.M.
Published: August 2009

This paper describes some aspects of new software development and its academic application. This program is an alternative to enhance and to improve the available resources for students to acquire practical knowledge in plastic injection molding parameterization. A virtual injection molding environment has been developed, which allows preliminary machine capacity determination, number of cavities analysis, injection cycle parameter definition, and defects analysis and representation. The environment allows the student to carry out an iteration process in order to optimize the injection molding process parameters. All decision making is based on an Expert System which response is similar to a skilled machine operator.
Application of New Educational Methodologies Adapted to the EHEA Guidelines for Manufacturing Engineering Teaching in University Curricula
Authors: Franco Patricio , Sánchez Horacio T. , Estrems Manuel , Monreal S. , Faura F.
Published: August 2009

Since the birth of European Higher Education Area (EHEA), the higher education institutions of European countries have been involved in the complex process of re-designing of their curricula according to the new educational criteria oriented to the convergence of contents and methodologies in teaching university curricula. According to the principles pursued by the so named Bologna process, the present work is focused on the description of experiences accumulated by these authors in adaptation of their courses of manufacturing engineering, as a previous stage to complete re-formulation of study plans for engineering programmes that are taught in Escuela Técnica Superior de Ingeniería Industrial (ETSII) of Universidad Politécnica de Cartagena. The strategies followed for the enhancement of the interest of students towards the theoretical and practical teachings, and the promotion of traverse and specific competences specially associated to these courses are explained in this work, as well as the academic results provided by the new educational methodologies assumed for the teaching-learning process.
Study of the Student’s Workload for the Manufacturing Related Subjects within the European Higher Education Area
Authors: Sánchez Horacio T. , Franco Patricio , Zamora R. , Estrems Manuel , Faura F.
Published: August 2009

Within the framework in which the Spanish universities are involved, the ECTS credit must be considered as the working hours needed for the students to acquire the subject related knowledge, capabilities and skills. The work presented in this paper consists of analyzing the data obtained by the surveys made by the students registered in manufacturing engineering subjects of the Technical University of Cartagena. This information lets us to estimate the workload needed for the subject adaptation process within the European higher education area framework.
Reclamation of Polymer PET Substrate Using T-Form Tool
Authors: Pa Pai Shan
Published: August 2009

In the current study, a reclamation module uses micro electroetching as a precision fabrication with a new design of T-form tool to remove the defective Indium-tin-oxide (TCO) nanostructure from the optical PET surfaces of digital paper display is presented in current studies. The adopted precision reclamation process requires only a short period of time to remove the TCO nanostructure easily and cleanly is based on technical and economical considerations and is highly efficient. A large rotational diameter of the cathode accompanied by a small gap width between the cathode and the workpiece corresponds to a higher removal rate for the TCO nanostructure. A small thickness of the electrodes, or a small edge radius of the electrodes takes less time for the same amount of TCO removal. A higher feed rate of the optical PET diaphragm combines with enough electric power to drive fast etching rate. High rotational speed of the T-form tool can improve the effect of dregs discharge and is advantageous to associate with the fast feed rate of the workpiece (optical PET diaphragm).
Calculating of the Temperature Distribution of Primary Shear Zone in Orthogonal High Speed Cutting Based on the Non-Uniform Volume Moving Heat Source
Authors: Li Guo He , Wang Min Jie
Published: August 2009

A method was presented for calculating the temperature distribution of primary shear zone in orthogonal high speed cutting based on the non-uniform volume moving heat source. The temperature distribution of primary shear zone in orthogonal high speed cutting was calculated by the dynamic plastic constitutive relationship and the distribution of strain and strain rate of primary shear zone. The results show that the temperature distribution of primary shear zone is uneven, from the original plane to the cutoff plane, the cutting temperature increases continuously. In the middle of primary shear zone, the change of cutting temperature is larger, at the position near to original plant and cutoff plane, the change of cutting temperature is smaller. The cutting temperature increases with the increase of cutting speed and cutting depth, but decreases with the increase of rake angle. The comparison with existing method shows that the method presented in this paper is not only available, but also simple, convenient and more accord with the fact of orthogonal high speed cutting.
The Predictive Model of Surface Roughness and Searching System in Database for Cutting Tool Grinding
Authors: Wang Yung Cheng , Chen Chen Hsiang , Lee Bean Yin
Published: August 2009

Due to the rapid development in recent cutting technology, demands for different types of precise cutting tools become increasingly complicated. Since the design and grinding of end-mills are the last and the most important processing for cutting tools. The geometrical accuracy and the cutting performance of an end-mill depend essentially on the grinding. However, the complicated geometry of an end-mill will be ground by the specific software of CAD/CAM on the 5-axis CNC tool grinding machine. The precision of end-mill grinder will be determined by the performance of 5-axis CNC tool grinder and setting of grinding parameters. Three regulation factors for grinding are grit size of the diamond grinding wheel, grinding speed and the feeding speed. The variable ranges of each parameter can be divided in large, medium and small interval. In this study for an end-mill with fixed geometrical profile, a series of different grinding parameters have been utilized by the 33 factorial experiment planning. And tool grinding experiments for the rod material specification of tungsten carbide have been performed by 5-axis CNC tool grinder. After grinding, surface roughness of tools will be measured. The reliability and precision of the end-mill grinding can be enhanced by the prediction model of polynomial network for surface roughness of end-mills. Besides, the database system for cutting tool has benn established. Totally 4802 data were constructed in the relational database according to the characteristics of tools.
A Novel Design of Calibration Equipment for 6-Component Huge Force Sensor and Coupling Modification
Authors: Zhang J. , Peng Z.L. , Li Y.J. , Qian Min
Published: August 2009

This paper presents the research on calibration for a 6-component huge force sensor. 6-component huge force sensor is used to measure the loading forces Fx, Fy, Fz and moments Mx, My, Mz. Static calibration equipment is studied. In order to express the relationship between input force signal and output electric signal when the sensor is used, a coupling matrix is needed. In this paper, a method for establishing the coupling matrix is developed. The matrix is used to calculate the input signal when sensor works in the simulation application, and the result shows it serves the sensor well.
Tool-Life Optimization in High-Speed Milling of Aeronautical Aluminum Alloy 7050-T7451
Authors: Pan Y.Z. , Ai Xing , Zhao Jun , Fu X.L.
Published: August 2009

A new approach is presented to optimize the tool life of solid carbide end mill in high-speed milling of 7050-T7451 aeronautical aluminum alloy. In view of this, the multi-linear regression model for tool life has been developed in terms of cutting speed and feed per tooth by means of central composite design of experiment and least-square techniques. Variance analyses were applied to check the adequacy of the predictive model and the significances of the independent parameters. Response contours of tool life and metal removal rates were generated by using response surface methodology (RSM). The analysis results show that it is possible to select an optimum combination of cutting speed and feed per tooth that improves metal removal rate without any sacrifice in tool life.
Experimental Research on Surface Roughness in High Speed Milling of Complex Surface Mold Steel
Authors: Yan Cao Qing , Zhao Jun , Li Yue En , Han Shi Guo
Published: August 2009

Complex surface mold has been widely used in various industries, and high efficiency and high quality can been achieved through high-speed CNC milling processing. Surface roughness including transverse and longitudinal roughness is an important criterion for mold quality. A high-speed milling experiment was performed in mold steel P20 using cemented carbide ball-end mill to investigate the surface roughness. The effects of process parameters on roughness including spindle speed, feed per tooth and radial cutting depth were examined, and an analysis on the mechanism for two kinds of roughness of different tool paths was finished. The experimental results show that the longitudinal roughness improve obviously while the spindle speed and the feed per tooth increase on the high-speed conditions, and the transverse roughness increase significantly when the radial cutting depth increases. And for a smaller roughness value, the tool path should be selected along the direction in which the curvature changes evidently.
Research on Thermal Error Modeling of NC Machine Tool Based on BP Neural Networks
Authors: Guo Qian Jian , Qi X.N.
Published: August 2009

Through analysis of the thermal errors affected NC machine tool, a new prediction model based on BP neural networks is presented, and ant colony algorithm is applied to train the weights of neural network model. Finally, thermal error compensation experiment is implemented, and the thermal error is reduced from 35μm to 6μm. The result shows that the local minimum problem of BP neural network is overcome, and the model accuracy is improved.
Folding Method and Controlling Tactics of the Tire Building Hub Based on the Parallel Mechanism
Authors: Guo Zong He , Wang Ke Jie , Zou Zhong Yue
Published: August 2009

This paper analyses the tire building hub mechanism, and the law in the course of working is studied. In accordance with principles of variable topology, the characteristics of the topology of the tire building hub is researched, and kinematics simulation analysis and verification are carried out. Based on the parallel mechanism, the new hubs are given, the types of the parallel mechanism are enumerated, which can achieve trajectory of the hub, and the folding way and controlling method of the tire building hub are ameliorated.
The Study on the Surface Abrasion about Wafer Final Polishing
Authors: Won Jong Koo , Lee Jung Taik , Lee Eun Sang
Published: August 2009

Polishing is one of the important methods in manufacturing of Si wafers and in thinning of completed device wafer. This study will report the evaluation on abrasion of wafer according to processing time; machining speed and pressure which have major influence on the abrasion of Si wafer polishing, for this, this study design the head unit and analysis head unit. After that, apply to experiment. It is possible to evaluation of wafer abrasion by load cell and infrared temperature sensor. The evaluation of abrasion according to processing condition is selected to use result data that measure a pressure, machining speed, and the processing time. This result is appeared by abrasion in machining condition. Through that, the study cans evaluation a wafer abrasion in machining. It is important to obtain mirror-like wafer surface.
CBN Slipstone Super-Accurate Grinding Theoretical Analysis and Application
Authors: Chen J.F. , Cui J.H. , Li F.
Published: August 2009

In this paper, the principle and impact factors for super-accurate grinding are analyzed and discussed. A comparative test is made to investigate the differences between advanced cubic boron nitride (CBN) slipstone and ordinary CBN abrasive corundum in performance such as grinding force, grinding temperature, metal surface metamorphic layer and so on. Based on these results, we design and manufacture a carding Laura slot super-accurate grinding machine. This new grinding machine is standard in system, compact in structure and perfect in appearance. Its fixture has a high positioning accuracy. The surface roughness of the Laura manufactured on the new grinding machine has reduced to Ra0.01μm. The productivity of the new machine increases by 25 times.
Experimental Study of Tangential-Feed Centerless Grinding Process Performed on Surface Grinder
Authors: Xu Wei Xing , Wu Yong Bo , Sato Takashi , Liang Z. , Lin Wei Min
Published: August 2009

In our previous study, a new centerless grinding method using surface grinder was proposed. In this method, a compact unit consisting mainly of an ultrasonic elliptic-vibration shoe, a blade, and their respective holders is installed on the worktable of a multipurpose surface grinder to conduct tangential-feed centerless grinding operations. For the complete establishment of this new method, firstly in this paper workpiece rotational speed control tests were carried out to make sure that the workpiece rotational speed is exactly controlled by the elliptic vibration of shoe to achieve high-precision centerless grinding. Then, the effects of the process parameters such as the worktable feed rate, the stock removal and the workpiece rotational speed on the workpiece roundness were clarified experimentally. The obtained results showed that (1) The workpiece rotational speed can be controlled exactly by the shoe ultrasonic vibration, (2) The roundness is improved with the increases in the voltage applied and the stock removal, but the decrease in the worktable feed rate; The best roundness obtained was 0.84m.