bluuebunny/crossref_metadata_2025 huggingface dataset:
A Formal Approach for the Validation of Web Service Orchestrations
Authors: Sellami Wael , Kacem Hatem Hadj , Kacem Ahmed Hadj
Published: July 2013

A web service composition is considered as a real revolution in SOA (Service Oriented Architecture). It is based on assembling independent and loosely coupled services to build a composed web service. This composition can be described from both a local or a global perspective by respective orchestration or choreography. The validation of web service orchestrations is the main topic of this work. It is based on the verification of two classes of properties: generic and specific properties. The former can be checked for any invoked web services whereas the specific properties are different interdependence relationships between activities within an orchestration process. These properties cannot be directly verified on the orchestration process, so, the authors have to use formal techniques. In this paper, they propose a formal approach for the validation of web service orchestrations. This work adopts WS-BPEL 2.0 as the language to describe the web service orchestration and uses the SPIN model-checker for the verification engine. The WS-BPEL specification is translated into Promela code which is the input language for the SPIN model-checker, in order to check generic and specific properties expressed with LTL (Linear Temporal Logic).
Analysis of the Integrated Implementation of the Manufacturing Engineering Subject in Engineering Degrees at the Malaga University
Authors: Sevilla L. , Martín M.J. , Martín F. , Trujillo F.J. , Bermudo C.
Published: July 2013

In this paper the integrated implementation of the Manufacturing Engineering subject in all new engineering degrees at the University of Malaga is analyzed, within the European Higher Education Area (EHEA) framework. After identifying the methodology used by Department of Engineering Manufacturing Process and the problems generated in its development, the robustness of the designed organization system is justified. This methodology has successfully overcome the negative effects of multiple changes made to the delivery of the first edition of this subject. Additionally, the methodology developed has generating a significant level of student satisfaction by comparison with near departments and overall university.
New Trends in Higher Education for a Thinner Approach to Technological Needs of Manufacturing Companies
Authors: Fernández A. , Urbicain G. , Calleja A. , de Lacalle L.N. López
Published: July 2013

The High Performance Manufacturing Group is established and grows from the 80's until now within the Department of Mechanical Engineering of the University of the Basque Country (UPV/EHU). The group's work focuses on teaching and research on manufacturing processes, primarily: metal removal processes, EDM, laser-processing techniques and grinding. To develop the investigations, the group has a workshop equipped with the latest technology machines manufactured by nearby companies of the machine tool sector. Furthermore, the workshop makes use of instrumentation systems for forces, temperatures or other parameters acquisition, in order to obtain the maximum amount of information from each test.With the objective of reducing the gap between industry and academic-scientific fields, it has been recently established the Machine Tool Unit. This initiative aims to provide advanced training in the field of Machine Tools and Manufacturing Technology. For this purpose, the unit gives strong theoretical formation along with practical training in companies and/or technological canters. Classes are taught both by own staff of the university as by external agents from research centers who develop R & D + i activities.
Assessing the Acquisition of Generic Skills in Open Postgraduate Studies in Advanced Manufacturing Engineering
Authors: Domingo Rosario , Claver J. , Álvarez R.
Published: July 2013

This study intended to define and implement activities to ensure the acquisition of generic skills and to evaluate the acquisition by students from the perspective of the latter and from the teacher. This research focuses on official postgraduate studies, which develop in the field of Advanced Manufacturing Engineering in open teaching. To obtain the data, combined analysis of teachers (internal vision) and student surveys (external view). The results from the insight they give an idea of activities designed, although focused on knowledge, abilities and technology skills, combining a methodology that implicitly has contemplated generic skills; moreover, the external view corroborate it, especially considering the student profile and the specialty studied, but also detect some aspect of improving.
Online Activities Development to Improve the Understanding of the Processes for Sheet Cold Forming
Authors: Álvarez R. , Claver J. , Lobo D. , Domingo Rosario
Published: July 2013

When it comes to teaching of manufacturing processes and more specifically in the related processes to sheet metal forming, communication technologies now allow the development of set of online activities in order to enable the student to understand some of the scientific basis of this process. The aim of this paper is the introduction of new teaching methodologies in the learning of subjects, to get more involved students in the learning process. To this end, activities that allow the simulation of metal sheet forming processes have been realised. These processes are required to manufacture a workpiece, thus understanding the required force to the process and analyzing the stress and temperatures developed during the process enable to students to make decisions on the suitability of the process. This paper develops the mentioned activities and connects them with the skills to be acquired by distance learning students, join with their implementation.
Design and Development of Integrated Lab-Practical Class in Manufacturing Engineering
Authors: Batista Moisés , Salguero Jorge , Álvarez Miguel , Gómez A. , González J.M. , Mayuet Pedro F. , Fernández S.R. , Marcos Bárcena Mariano
Published: July 2013

University studies have changed in Spain in the last five years in order to adequate them to the European Space for Higher Education. Under these changes Spanish law fixes the skills and abilities that must acquire the Graduates in Engineering with competences and applications in the Industrial Field. Among them, it can be found the corresponding to Manufacturing Engineering. In this work an Integrated Lab-Practical Class has been performed including different stages of a Manufacturing Process from the Product/Process Design to the Final Product. This Practical Class is developed in six sessions. This experience has shown the interest of the students for the contents of the subject and its relationship with the theoretical concepts.
Simulation Tools as an Educational and Training Resource in Manufacturing Engineering Subjects Teaching
Authors: García-García M. , Soriano E. , García-Alonso M.J. , García-García E. , Sánchez-Lite A.
Published: July 2013

Education & Learning Process at Manufacturing Engineering subjects requires the use, at every educational level, of resources and technologies that improve professor educative practice and student contents and competences acquisition. In this work it is showed the use of a 3D simulation tool for virtual models creation, carried out by National Distance University of Spain and the Salesianos Atocha School at Madrid, Spain, within the practical part of several subjects of their manufacture engineering studies and professional formative. It is analyzed and discussed the development of a virtual model that simulates a lathe gearbox manufacturing project in the classroom. A 3D CAD geometry is used as a base for the calculation and design of all the gearbox components (main spindle, chuck ́s joints, gears, change of feed, etc.). This methodology, used with every lathe component, permits the presentation of the machine as a whole and the analysis of the gearbox development in it. Human factors, assembly time, workplaces development and 3D lines design are studied and analyzed within the proposed model. The programs which have been used to develop this work are: Inventor 2009, Adobe Premier and 3D Studio Max R6. The final results can be displayed into several digital formats which help with the pedagogical model promotion.
Room Temperature Ferromagnetism in Ti0.985Co0.015O2-δ Thin Films Grown by Pulsed Laser Deposition Technique
Authors: Mohanty P. , Ganeshan V. , Rath Chandana
Published: July 2013

Ti0.985Co0.015O2-δ thin films are deposited at 0, 0.1, 1 and 300 mTorr oxygen partial pressures by pulsed laser deposition (PLD) technique. Glancing angle x- ray diffraction (GAXRD) and micro-Raman spectroscopy show that the phase changes from rutile to anatase with increasing oxygen partial pressure. From Rutherford backscattering spectroscopic (RBS) technique, O to (Ti+Co) atomic ratio is found to increase with increasing oxygen partial pressure. Further, the simulation of RBS data while reveals non-uniform distribution of Co throughout the film deposited at 0 and 0.1 mTorr oxygen partial pressures, at 1 and 300 mTorr oxygen partial pressure, Co distribution is found to be uniform. Magnetic measurements confirm the room temperature ferromagnetism (RTFM) in all the films independent of the phase. Magnetic force microscopy (MFM) further supports the ferromagnetic nature of the films. We attribute the ferromagnetism in the films to be arisen from defects like oxygen vacancies rather than any contamination or Co clustering.
Synthesis of Thermostable Amylase Enzyme from Bacillus licheniformis and it's Optimization to Different Sources
Authors: Nanda Anima , Sudhakar T. , Nayak B.K. , Kumar J. Prem
Published: July 2013

S: - Among the six isolated amylase producing strains,Bacillus licheniformis(B1), the thermostable strain was selected from the soil of a paddy field. Its enzyme productivity and activity were evaluated. The activity of enzyme was calculated as 27.77 IU/ml. Effects of various carbon and organic nitrogen sources, and C/N ratio on enzyme production were examined. Maximum α - amylase production was obtained in medium containing 1% starch. Fructose supported the maximum amylase production among all the sugar studied. Of the organic nitrogen sources tested, peptone was found to be the best organic nitrogen source for excess yield of the enzyme. The optimum C/N ratio was found to be 1:1. The α amylase exhibited activity at a wide pH and temperature range and activity were found to be optimal at pH 6 and 40 °C respectively. The molecular weight of α amylase was calculated by sodium dodecyl sulphate gel electrophoresis and found to be around 29,000 Daltons.
Comparative Analysis of Antibiotic Effect of AgNO3 and Silver Nanoparticles Synthesized from Penicillium fellutanum
Authors: Nanda Anima , Majeed Shahnaz
Published: July 2013

The proposed study was to synthesize silver nanoparticles by using filamentous fungus Penicillium fellutanum. From the ancient period, silver has been used against microorganisms due to its own antibacterial properties. The fungal culture of Penicillium fellutanum was isolated from the soil samples of Sathyabama University, Chennai, Tamil Nadu, India. The fungal isolates were inoculated in culture medium and incubated at room temperature for three days and the culture filtrate was separated and divided into two parts. One part of the culture filtrate was mixed with equal volume of 1mM silver nitrate [AgNO3,(1 mM)] and agitated at room temperature in dark condition. And the second half was kept as such. In the other hand only 1mM silver nitrate was added into the equal volume of Milli Q water and one half was plain Milli Q water. All the four samples were tested against pathogens like Bacillus cereus, E. coli, Proteus vulgaris, Staphylococcus aureus, Staphylococcus epidermidis and the results were compared. Proteus vulgaris showed the highest zone where E coli showed the least zone of inhibition, in the culture filtrate added with silver nitrate. The cell filtrate on treatment with silver nitrate and prior incubation were observed for change in color and characterized by UV-Vis spectrophotometer which detected AgNPs in the solution. The maximum absorbance 410nm confirmed the formation of silver nanoparticles. Size and morphology of silver nanoparticle were investigated using Atomic Force microscopy (AFM). The silver Nanoparticles after confirmation were checked for its antibacterial activity against selected pathogenic bacteria. The biologically synthesized Nanoparticles from Penicillium fellutanum showed the good inhibitory effect against the selected pathogens, which would be the novel remedy substituent in the place of high dose antibiotics.
Linear Assembly of Oxidized Surface Treated Nanodiamonds in Polymer-Based Nanohybrids by Electric Field Inducement
Authors: Nguyen Son Thanh , Cho Hong Baek , Nakayama Tadachika , Huynh Minh Triet Tan , Suematsu Hisayuki , Suzuki Tsuneo , Jiang Wei Hua , Tanaka Satoshi , Tokoi Yoshinori , Niihara Koichi
Published: July 2013

Linear assembly of densely packed oxidized nanodiamonds (OxNDs) was achieved in polyepoxide-based nanohybrid films. A homogeneous suspension of pre-polymer of polyepoxide and OxNDs was cast onto a polyamide-spacer and subjected to an electric field in order to induce relocation and stretched-assembles of the fillers before the mixture became cross-linked. The OxNDs suspended readily, forming linear assemblies of OxNDs (LAOxNDs) of varying thicknesses, and aligned vertical to the film surfaces. Nanohybrid films with assemblies of LAOxNDs led to a significant enhancement in thermal conductivity while maintained the electrical insulation property of the polyepoxide. Mechanisms for the formation and structural variation of LAOxNDs in the matrix are elaborated regarding the improvement in physical properties. The present ambient-oxidation process and field-induced application are simple, but effective in enhancing the thermal properties of the polymer-based hybrids, and hence, promising for applications in the semiconductor industry, such as thermal interface materials.
Characterization of Hydroxyapatite Containing of Titanium Hydride Sintered Body by Nano Size Powder
Authors: Ishiwata Kazuki , Tawara Kazumasa , Matsushita Junichi
Published: July 2013

The material study on bioactivitying artificial bone is lacking results for improve the quality of life (QOL) for individuals to fulfill their happy life in the society, which requires artificial bone to be replaced with neonatal bone by absorbing, regenerating the bone, which is not possible. Hydroxyapatite Ca10(PO4)6(OH)2, (HAp) has excellent biomaterial for biomedical and dental applications because of its superior properties. However, HAp had poor mechanical properties such as low hardness and fracture toughness. In this study, HAp containing titanium and titanium hydride (TiH2) sintered bodies were studied in order to investigate the possibility of its advanced biomaterials application. The nano particle size starting powders were milled by using mortar and muddler equipment. The sintered bodies were prepared by pressureless sintering at argon-hydrogen gas atmosphere. The samples were evaluated for bioactive performance by using simulated body fluid (SBF) solution for. The HAp-Ti, the HAp-TiH2 composite material is attractive as a bioceramics compared with HAp ceramics.
Optical and Photovoltaic Properties of CdS/Ag2S Quantum Dots Co-Sensitized-Solar Cells
Authors: Tubtimtae Auttasit , Lee Ming Way
Published: July 2013

Subscript textWe present a co-sensitization of CdS/Ag2S quantum-dot as sensitizers for solar cells. The optical properties of single and double-layered quantum-dot conditions were monitored using UV-Vis spectrophotometer. The results show that the different characteristics of absorption spectra depended on the types of QDs, indicating to the different energy gap of each QDs deposited on TiO2 surface and the tunable absorption ranges of the sample of double-layered quantum-dot-sensitized TiO2 electrodes are broader and the absorption intensity are higher than the single-layered quantum-dot, attributed to the co-absorption of two QDs to the light and both CdS and Ag2S are activated in visible to near-infrared region (450-1100 nm). The photovoltaic data shows that the highest efficiency of 1.41% with a photocurrent density, Jsc of 20.6 mA/cm2, an open-circuit voltage, Voc of 0.32 V and a fill factor, FF of 21.3% were yielded by the sample of CdS(3)/Ag2S(4) as an optimum condition of dipping cycles for CdS and Ag2S under irradiance of 100 mW/cm2 (AM 1.5G).
Preparation and Electrical Conductivity of Sr(Zr1-xAlx)O3-x/2 Perovskite Solid Solution (x = 0-0.5)
Authors: Oitate Ryuji , Hirata Yoshihiro , Sameshima Soichiro , Matsunaga Naoki
Published: July 2013

Perovskite solid solution of Sr(Zr1-xAlx)O3-x/2 was prepared by a coprecipitation method using corresponding aqueous solutions and ammonium carbonate solution. The freeze-dried powders at x = 0-0.5, heated at 1000°C for 4 h in air, were identified to be an orthorhombic SrZrO3 solid solution. The highest electrical conductivity of Sr(Zr1-xAlx)O3-x/2 system sintered at 1400°C was measured at x = 0.2 (3.80×10-4 S/cm at 800°C, activation energy 109 kJ/mol ). The activation energy also showed a maximum value at x = 0.25 .
The Thermal Expansion Characteristics of Epoxy Resin/Crepe Paper Composites for High-Voltage DC Bushing
Authors: Gao Nai Kui , Wu Chun , Zhang Wen Xi , Xu Zhou , Jin Hai Yun
Published: July 2013

Abstract. In this paper, the thermal expansion characteristics of epoxy resin/crepe paper composite insulation structure for high-voltage DC bushing were studied. The results showed that when temperature was lower than the glass transition temperature(Tg) of epoxy resin, coefficients of thermal expansion along axial and radial direction of the insulation structure increased with increasing temperature; When higher than Tg, with an increasing temperature, the CTE along radial direction of the structure increased-even larger than the pure epoxy, while axial decreased. Tg is obtained by DSC. The microstructure of high-voltage DC bushing was observed by polarizing microscope. On the basis of the above analysis, the different trend in thermal expansion characteristics may be resulted from the sample structure, fiber distribution of crepe paper and the movement of epoxy resin molecular chains.
Fabrication and Characterization of Calcium Silicate Phosphors - Ca2SiO4 and Ca2MgSi2O7 -
Authors: Watari Takanori , Tsuji Tomohiro , Mori Komei , Luitel Hom Nath , Torikai Toshio , Yada Mitsunori , Xu Chao Nan , Terasaki Tadashi
Published: July 2013

Calcium silicate phosphors, Ca2-xSiO4(CS):Eu3+x, CS:Eu2+x and Ca2-y-zMgSi2O7 (CMS):Eu2+y,Dy3+z were prepared by the solid state reaction. The phases in CS:Eu3+ system were β- and αL’ -types. The fluorescent color under a black-light irradiation was red and the emission spectrum consisted of 590nm(αL’), 615nm(β) and 625nm(αL’) peaks. The emission intensity took a maximum value at x=0.2. The addition of B3+ accelerated the solid solution of Eu3+. The phase in CS:Eu2+ system was β-type only. The fluorescent color was yellow-green(520nm). The emission intensity took a maximum value at x=0.01. The CMS product showed the akermanite phase. The lattice constants of CMS:Eu2+ increased with increasing Eu content, but those became constant at y>0.05. The fluorescent color of CMS:Eu2+ was yellow-green and the emission intensity took a maximum value at y=0.03. In the case of CMS:Eu2+0.03,Dy3+z, the fluorescent color and the afterglow color were same, yellow-green. The emission intensity took a maximum value at z=0.06. The longest afterglow time, 23min., was obtained at z=0.09. The trap depth were 0.64-0.69 eV.
Preparation of the Catalyst for Methanol Steam Reforming from Cr–Zr Amorphous Alloys
Authors: Matsusako Toshiya , Kai Takami , Nakazato Tsutomu , Kimura Hisamichi , Goto Takashi , Kato Hidemi
Published: July 2013

Amorphous Cu–Zr metallic alloys were studied as precursors to catalysts for methanol steam reforming to produce hydrogen. The alloy ribbons were prepared by single-roll rapid solidification, and the optimum pretreatment method and conditions were determined. The activity of the catalysts prepared by the improved pretreatment method was greater than that of previously prepared catalysts by two degrees of magnitude. The addition of a very small amount of Pt enhanced the activity without increasing CO formation.
Softening Kinetics in High Al-Nb Microalloyed Steels
Authors: Aretxabaleta Z. , Pereda Beatriz , Parker S.V. , López Beatriz
Published: July 2013

The combined effect of Al and Nb additions on the static softening behavior of C-Mn steels was investigated. The compositions of the steels studied in this work are representative of the recently developed TRIP-assisted steels: a base composition of 0.2wt.%C, 2wt.%Mn, 50ppmN, three different Al levels, 0.03 (base steel), 1 and 2wt.%, and two Nb contents of 0.03 and 0.07wt.%. Double-hit torsion tests were performed at different deformation temperatures (925-1065oC) and pass-strains (=0.2 and 0.35). It was found that solute Al produced a significant retardation on the static softening kinetics, this effect being enhanced by the addition of Nb. Additionally, below 1000oC the addition of 2 wt.%Al promotes the γα phase transformation to occur concurrently with softening. For the Nb microalloyed steels strain induced precipitation also occurred, resulting in a complex interaction between softening, phase transformation and strain induced precipitation.
Numerical Simulation of Casting Thermal Stress and Deformation Based on Finite Difference Method
Authors: Chen Tao , Liao Dun Ming , Zhou Jian Xin
Published: July 2013

Thermal stress simulation is an important part in the numerical simulation of casting process. It provides engineers with insights into the evolution of displacement, strain and stress of castings in the solidification process. With thermal stress simulation, some defects of casting, i.e. hot tearing, cold cracking and large deformation can be predicted and the engineers are instructed to optimize and improve the casting process. Based on the finite difference method (FDM), this paper presents an integrated numerical method to simulate the thermal stress and deformation of casting in the solidification process. Practical examples show that the method is capable to predict stress distribution and deformation as well as the defects in the experiment.
Research and Development on CAD/CAE Integration of Casting Process System Based on IGES Neutral File
Authors: Tang Hong Tao , Zhou Jian Xin , Shen Xu , Liao Dun Ming , Pang Sheng Yong , Wan Lin
Published: July 2013

Nowadays, most 3D casting process CAD systems are developed based on second development tools of various 3D CAD systems. However the type and version escalation of various 3D CAD systems in foundry enterprises greatly limit the application of 3D casting process CAD systems. By the data exchange between the neutral file format of 3D geometric model, these problems can be well solved. In this study, by taking advantage of universal CAD data-exchange standard iges for data exchange, a practical 3D CAD system was developed based on opencascade geometry kernel. The system has the function of design and modeling of practical casting process such as part information extraction, parting surface, gating system, riser system and so on. Finally taking a steel casting for example, the casting process is exported in the file of stl and the simulation analysis is carried by intecast software which demonstrate the system based on iges neutral file can well support the integration of casting CAD and CAE.
Advanced Methods in Modelling of Metallurgical Unit Operations
Authors: Järvinen Mika , Visuri Ville Valtteri , Pisilä Sauli , Kärnä Aki , Sulasalmi Petri , Heikkinen Eetu Pekka , Fabritius Timo
Published: July 2013

This paper summarizes and discusses our recent work on modelling of several steelmaking processes. The work started by developing a detailed sub-model for a single gas bubble reacting in liquid steel. The key feature in this model was an approach based on LOMA, Law of Mass Action, which was employed for defining the chemical rate of a reaction in a robust way. The bubble reaction model was then coupled with a new simulator concept for the AOD process, Argon-Oxygen Decarburization. After a successful validation, the same approach was used to model chemical reactions and chemical heating of liquid steel in the CAS-OB process, Composition Adjustment by Sealed Argon Bubbling Oxygen Blowing,using a supersonic lance. Finally, a new model was developed and implemented into the existing AOD process model for slag reduction with slag droplets. The purpose of this paper is to present a generalised framework for applying and validating the LOMA approach into modelling of metallurgical unit operations. In addition, the use of Computational Fluid Dynamics (CFD) in the validation and verification work is discussed.
Modelling of Grain Refinement Induced by SMAT Process, Using a Complete Numerical Chaining Methodology
Authors: Benafia Souhail , Retraint Delphine , Panicaud Benoit , le Joncour Lea , Rouhaud Emmanuelle , Micoulaut Matthieu
Published: July 2013

Surface Mechanical Attrition Treatment (SMAT) is a recent process that enables to nanocrystallise the surface of metallic alloys. It can thus enhance mechanical properties of the treated material by inducing a grain refinement down to the nanometre scale, in the top surface layer. This nanocrystallisation process leads to different effects that were successively studied on several metallic materials. In the present work, investigations are carried out on the modelling of SMAT. A simulation of the shot dynamics is performed using different process parameters, with the aim to obtain the impact velocity field on the treated surface. This field is then used as an input for a finite element model to predict the induced grain refinement. The evolution of the micro and nanostructures are then calculated using a micromechanical approach, which takes into account the dislocations and their interactions. Coupled with a finite element analysis, this approach enables to deduce the influence of the process on the macroscopic material properties, whatever the geometry of the sample.
Challenges in Finite Element Simulations of Chain of Manufacturing Processes
Authors: Lindgren Lars Erik , Lundbäck Andreas , Edberg Jonas , Svoboda Ales
Published: July 2013

Simulation of some, or all, steps in a manufacturing chain may be important for certain applications in order to determine the final achieved properties of the component. The paper discusses the additional challenges in this context.
Application of a Material Model to Predict Rolling Forces and Microstructure during a Hot Ring Rolling Process
Authors: Henke Thomas , Hirt Gerhard , Bambach Markus
Published: July 2013

Ring rolling is an incremental bulk forming process. Hence, the process consists of a large number of alternating deformations and dwell steps. For accurate calculations of material flow and thus ring geometry and rolling forces in hot ring rolling processes, it seems necessary to consider material softening due to static and post dynamic recrystallization which could occur between two deformation steps. In addition, due to the large number of cycles, the modeling results, especially the prediction of grain size, can easily be affected by uncertainties in the input data. However, for small rings and ring material with slow recrystallization kinetics, the interpass times can be short compared to the softening kinetics and the effect of softening can be so small, that microstructure evolution and the description of the materials flow behavior can be de-coupled.
In this paper, a semi-empirical JMAK-based model for a stainless steel (1.4301/ X5CrNi18-9/ AISI304) is presented and evaluated by the use of experiments and other investigations published in [1],[2]. Finite Element (FE) simulations of a ring rolling process with a high number of ring revolutions and thus multiple, incremental forming steps were conducted based on ring rolling experiments. The FE simulation results were validated with the experimentally derived rolling force and evolution of ring diameter. The microstructure evolution was calculated in a post processing step considering the investigated evolution of strain and temperature. In this calculation the interrelations between the fraction of dynamically recrystallized microstructure, the evolution of post-dynamically recrystallized microstructure and the final grain size have been considered. Both, the calculated final microstructure and the evolution of rolling force and ring geometry calculated stand in good agreement with the experimental investigations.
The Numerical Simulation Research of Thermal Mechanical Simulation Compression Behavior with Uneven Temperature on End
Authors: Yao Lei , Fang Zheng , Ge Zhang
Published: July 2013

The study has been performed concerning the influence of temperature field created by heat conduction between sample and the anvils, and the influence of lubrication condition (friction coefficient) on thermal mechanical compression test with numerical simulation, with regard to deformation resistance and distributions of strain and strain rate. The results show that temperature field has an effect on deformation resistance and distributions of strain and strain rate. That will influence on the results from thermal mechanical simulation tests. Further, the results also show that friction coefficient has no influence on deformation resistance, but the friction coefficient will result in uneven distribution of strain and strain rate.
Effect of Constrained Conditions on the Equivalent Strain and Microstructure of 5052 Al Alloy Deformed by Groove Pressing
Authors: Chen Wen Zhe , Yang Kai Huai , Huang You Ting
Published: July 2013

Three-dimensional finite element simulation (3D FES) and experiments were carried out for analyzing the deformation behavior, homogeneity, microstructure and properties of 5052 Al alloy during groove pressing (GP) with two different processing conditions, that is, constrained groove pressing (CGP) and unconstrained groove pressing (UGP). The simulation results show that the values of the equivalent strain and its distribution depend strongly on the constrained conditions. Especially, the equivalent strain and its distribution are inhomogeneous along X direction, with lower strain regions located at both ends and larger strain regions with periodic variation located at intermediate section. CGP results in a higher accumulative rate of equivalent strain than that of UGP. The average strain is equal to the theoretical strain for CGP, but it is much lower than its theoretical strain for UGP. The experimental results show that grain sizes of 5052 Al alloy can be refined significantly by CGP or UGP, while CGP has a higher rate of grain refinement and finer grains than that of UGP. And the results of microhardness confirmed the prediction of 3D FES.
Physical Modelling of the Interaction between Softening and Nb (C,N) Strain-Induced Precipitation in High-Mn Steels
Authors: Llanos Laura , Pereda Beatriz , Paul Georg , López Beatriz
Published: July 2013

The applicability of a physical model to describe the austenite microstructure evolution after hot deformation in High-Mn steels was investigated. Double-hit torsion tests were carried out to determine the softening behaviour of two High-Mn steels, one of them microalloyed with 0.11 wt% Nb. The values of the unknown parameters included in the model were determined by fitting experimental results. The model describes adequately the softening evolution of the steels. At high temperatures recovery and recrystallization contribute to mechanical softening, the latter having the main contribution. In contrast, when strain-induced precipitation occurs recovery has a larger effect.
The Effect of Bonding Flaws on the Splitting Process in the Smart-Cut Technology
Authors: Gu Bin , Yuan Wei Feng , Ning You Jun , Song Dan Lu
Published: July 2013

Smart-Cut®is an innovative and highly efficient technology to fabricate high quality Silicon-on-Insulator (SOI) wafers, especially when the top film of SOI wafers is very thin. In the present paper, a fracture mechanics model is established to examine the effect of bonding flaws on defect growth in the Smart-Cut process. It is found that although defect growth can occur in a practical Smart-Cut process, large bonding flaws are inclined resulting in severe deviation of the direction of defect propagation, leading to a non-transferred area of thin film when splitting. Moreover, at the expense of low defect growth, increasing the internal pressure of bonding flaws decreases the defect growth deviation and thus benefits to improve the quality of final SOI wafer. The mechanism of relaxation of stiffener constraint is proposed to clarify the effect of bonding flaws. Finally, progress of the splitting process is analyzed when bonding flaws are present.
Modeling of Steels and Steel Surfaces Using Quantum Mechanical First Principles Methods
Authors: Alatalo Matti , Pitkänen Heikki , Ropo Matti , Kokko Kalevi , Vitos Levente
Published: July 2013

We describe recent progress in first principles materials modelling applied to iron alloys. First principles methods in general have proven to be an effective way of describing atomic level phenomena in solids. When applied to alloys with chemical disorder, however, the widely used supercell methods turn out to be impractical due to the vast variety of different possible configurations. This problem can be overcome using the coherent potential approximation (CPA), which enables the description of a multicomponent alloy in terms of an effective medium constructed in such a way that it represents, on the average, the scattering properties of the alloy. A bulk alloy, in the case of substitutional random alloys, can thus be described with a single atom while a slab is needed to describe surfaces. The exact muffin-tin orbitals (EMTO) method provides a first principles method that can be combined with the CPA in order to describe steels and other multicomponent alloys. We describe the EMTO-CPA method and provide examples of both bulk and surface properties that can be modelled with this method.
Materials for Electronics by Thermal Spraying
Authors: Ronkainen Helena , Kanerva Ulla , Varis Tommi , Ruusuvuori Kimmo , Turunen Erja , Peräntie Jani , Putaala Jussi , Juuti Jari , Jantunen Heli
Published: July 2013

In this paper, dielectric and conductive properties of thermally sprayed Al2O3- and Cu-based coatings on steel and alumina substrates were studied. Alumina powders with nanoand micro-sized additions of Ni, NiO, TiO2, silica, and commercial glass were used in High Velocity Oxygen Fuel (HVOF) deposition. The conventional commercial copper powder and three Ag, WC and H2 -modified powders were used in Direct Write Thermal Spray (DWTS) deposition. Mixed phases of α-Al2O3 and γ-Al2O3 were found to be present in the as-deposited coatings. Sprayed alumina-based composites exhibited dielectric permittivity of 5.3-13.9 and losses of 0.002-0.178 at 1 MHz and 1 GHz while the additions tend to increase the values. Sprayed compositions with glass-type additions were found to retain α-Al2O3 crystalline phase after the deposition. Cu depositions, especially modified ones, realised by Direct Write Thermal Spray (DWTS) showed conductivity values as high as 4256 % of IACS values. The results demonstrate that ceramic and conductive coatings fabricated by thermal spray techniques show feasible properties for electrical applications, such as low-frequency components and insulation layers to be utilised in embedded 3D circuitry, in a way that is not possible through traditional manufacturing methods.
Comparison of Material Properties and Creep Behavior of 20MnCr5 and S275JR Steels
Authors: Brnic J. , Niu Ji Tai , Turkalj G. , Canadija M. , Lanc D. , Brcic M. , Krscanski S. , Vukelic G.
Published: July 2013

t is well known that the optimization procedure has an important role in the structure design. Furthermore, experimentally obtained data of material behavior is known to serve as the most relevant data in the mentioned design procedure. Therefore, this paper sets out to examine some experimentally determined data of the material subjected to certain environmental conditions. Based on these parameters, some analyses of material behavior can be made. In addition, data are of such nature that it is possible to make an appropriate comparison between the two investigated materials. Materials under considerations were 20MnCr5 steel and S275JR steel. Both of materials have been subjected to the same environmental conditions and the following properties can be singled out: ultimate tensile strength, 0.2 offset yield strength, the modulus of elasticity, elongation, creep behavior and Charpy impact energy. Each of the mentioned details are determined by the corresponding test, e.g. data related to strengths and to creep behavior are determined by tensile tests while impact energy is determined by Charpy impact test. In this way, the obtained values are presented in the form of the engineering stress-strain diagrams, creep curves and impact energy data.
Welding of Aluminum Matrix Composites
Authors: Niu Ji Tai , Gao Zeng , Cheng Dong Feng , Wang Xi Tao , Chen Si Jie
Published: July 2013

Aluminum metal matrix composites (Al-MMCs) are new promising materials for aviation, aerospace and automotive industries. However, due to the poor weldability they have very limited applications. In this paper, the authors present the welding achievements of Al-MMCs developed by their scientific research team in recent years. Laser welding, liquid phase impact diffusion welding and vacuum brazing were utilized. Based on analysis of microstructure, good joints can be achieved by using these welding methods.
Phase Transitions and Microstructural Processes in Shape Memory Alloys
Authors: Adiguzel Osman
Published: July 2013

Shape memory alloys exhibit a peculiar property, shape memory effect that is the result from the structural changes in microscopic scale. These alloys return to previously defined shapes when they are subjected to variation of temperature after deformation of the low temperature phase. Shape-memory effect is based on martensitic transformation, with which the material changes its internal crystalline structure. The ordered structure or super lattice structure is essential for the shape memory effect of the material.
Copper based alloys exhibit this property in the β-phase field, which possesses the simple bcc-structure at high temperature austenite phase. As the temperature is lowered, austenite phase undergoes martensitic transition following two ordering reactions, and microstructural changes in microscopic scale govern this transition. In the present work, Cu alloys were investigated by transmission electron microscope, TEM, and x-ray diffraction techniques.
Surface Patterning of Stainless Steel in Prevention of Fouling in Heat Transfer Equipment
Authors: Pääkkönen Tiina M. , Ojaniemi Ulla , Riihimäki Markus , Muurinen Esa , Simonson Carey J. , Keiski Riitta L.
Published: July 2013

Fouling of surfaces is a major challenge in design and operation of many industrial heat transfer equipment. Fouling causes significant energy, material and production losses, which increase the environmental impact and decrease economic profitability of processes. Even small improvements in prevention of fouling would lead to significant savings in a wide range of heat transfer applications. In this study, crystallization fouling of aqueous calcium carbonate solutions on a heated stainless steel surface is used to investigate the prevention of fouling in heat transfer equipment by physical surface modifications. Fouling behaviour of different surface patterns are studied experimentally in a laboratory scale fouling test apparatus. CFD modelling is used to study hydrodynamic and thermal conditions near surfaces with different patterns. In addition, the effect of surface pattern on the removal of particles is studied numerically. Surface patterning is found to affect the hydrodynamic and thermal conditions near the wall, and therefore to change the conditions for fouling layer build-up and removal, when compared to a flat heat transfer surface. The most promising surface pattern includes curved shapes, and it seems to create flow conditions in which improved convective heat transfer decreases the driving force for crystallization fouling. In addition, curved surfaces increase the shear forces at the wall, which prevents adhesion of the foulants to the surface and increases resuspension.
Tuning the Composition and Microstructure of Fe-Based Alloy Thick Coatings for Heavy Duty Applications
Authors: Rovatti Ludovica , Palamini N. , Vedani Maurizio , Schubert G.
Published: July 2013

Thick coatings for heavy duty applications in many industrial fields are produced by generating hard layers of Fe-based complex alloys on the critical surfaces. The composition and structure of these coatings have to be carefully tuned in order to generate a defect-free layer after solidification and to meet the expected service conditions.
The present study is aimed at investigating and developing improved Fe-based alloys for the above described thick coatings by a careful definition of the microstructural features required to bear service conditions and by defining the optimal compositions to achieve the desired properties.
Primary carbide distribution and size as well as steel matrix composition are the main microstructural features that will be evaluated in order to fine tune coating performance in terms of toughness and hardness. The experimental part of the investigation here presented will be mainly concerned to laboratory casting the above alloys and to assess their microstructure and properties.
Simulation of the Hot Extrusion Process of Sintered WCu40 Covered with a Steel Cup
Authors: Lin Qiang , Liu Zu Yan , Su Xin Yan
Published: July 2013

In this paper, based on the determination of the stress-strain relationship of sintered W-40wt.%Cu by upsetting tests, the hot extrusion process of the materials covered with a steel cup has been simulated by DEFORM. The effect of the thickness of steel cup, extrusion temperature and extrusion ratio on the extrusion process has been studied, so that a group of optimal parameters could be obtained which is useful to the experiment of powder compact by extrusion with cups.
Control of Microstructure by MaxStrain Device
Authors: Mandziej Stan T. , Ruggeri Marc
Published: July 2013

Grain refinement should increase strength of metallic materials in a predictable manner. However, in applications of severe plastic deformations for this purpose, limits have been observed due to self-recovery and strain-induced precipitation assisted by generation of adiabatic heat. Pure metals and single-phase alloys have not been the best candidates for achieving ultrafine-grained microstructures therefore more often precipitation-hardening multi-phase alloys have been used in SPD experiments. To generate ultrafine-grained microstructures by accumulated multiple compressive strains executed at various strain rates during programmed thermal cycles the MaxStrainTM device was developed for GleebleTM physical simulator. This paper deals with processing of Al-6061 wrought alloy and Al-319 cast alloy by the MaxStrain device, and describes obtained microstructures.
Physical Simulation on Microstructure and Properties for Weld HAZ of X100 Pipeline Steel
Authors: Liu Yu , Yang Liu Qing , Feng Bin , Bai Shi Wu , Xu Chang Xue
Published: July 2013

In this paper, the simulation heat affected zone (HAZ) continuous cooling transformation (SH-CCT) diagram of X100 pipeline steel was drew by using Gleeble 3500-HS thermal/mechanics simulation test machine, and the microstructure and properties of the HAZ of single-pass/double-pass welding were simulated and studied. The results show that the hardening trend of X100 pipeline steel weld coarse grain HAZ (CGHAZ) is significant when using the small welding heat input. To prevent the hardening of weld CGHAZ and reduce the cold cracking sensitivity, moderate heat input welding specification (between 12 and 18 kJ/cm) and weld preheating process (between 100 and 150°C) should be adopted. When appearing obvious embrittlement, the microstructure of double-pass weld intercritically reheated coarse grain HAZ (ICCGHAZ) of X100 pipeline steel is mainly upper bainite, the precipitation and the chain-like distribution of quantity more martensite-austenite (M-A) constituents in austenite grain boundaries is one of the main reasons leading to toughness deterioration. In conclusion, optimization control measures on the microstructure and properties of X100 pipeline steel weld HAZ are presented by above comprehensive analysis.
Thermodynamic Modeling of a Wide Thin Steel Plate Irradiated by a Moving Gaussian Laser Beam
Authors: Qiu Feng , Kujanpää Veli
Published: July 2013

This study developed a thermodynamic model to investigate the quasi-steady thermal process of a wide thin steel workpiece irradiated with a moving Gaussian laser beam. Equations were established for the temperature distribution and the Ac1 and Ac3 boundaries. The temperature distributions for diverse thicknesses were compared with that for infinite thickness at different laser traverse speed. The lag of the peak temperature relative to the center of laser beam is found to be limited.
The Preparation and Curing Kinetics of Epoxy/PhS(4, 4'-dihydroxydiphe-nylsulfone)/aluminum tris (tetradecylacetoacetate) Latent Resin System
Authors: Wan Zhi Min , Liu Yu Yan , Kang Hong Jun , Zhu Qi
Published: July 2013

In this paper, organic aluminum compound, aluminum tris (tetradecylacetoacetate) (Al-14) was synthesized, and its molecular structure was identified by IR spectrum. The investigation of the curing kinetic of epoxy resin system with PhS (4, 4-dihydroxydiphenylsulfone)/aluminum tris (tetradecylacetoacetate) (Al-14) latent catalysts was performed by differential scanning calorimetry (DSC) using an isothermal approach. All kinetic parameters of the curing reaction including the reaction order and activation energy were calculated and reported. The results indicated that the curing reaction of Ep/PhS/Al-14 compand system in this experiment proceeded through an autocatalytic kinetic mechanism.
Evaluation of the Fatigue Life in Aluminum Alloy Welded Joint by Nonlinear Ultrasonic Testing
Authors: Gang Tie , Wan Chu Hao , Zhu Rong Hua , Zhao Li Bin
Published: July 2013

Fatigue is a common phenomenon in welded structures. Prediction of fatigue life of welded joints in-service is still an unsolved puzzle by the conventional linear ultrasonic testing method. However, the nonlinear ultrasonic waves or the acoustic nonlinear signal can provide clear signs of the accumulative fatigue damage in materials, as reported by a number of researchers. Hence, the nonlinear ultrasonic testing method has revealed a tremendous potential for fatigue damage evaluation. This paper presents a study to characterize the fatigue damage using the analysis of the signal characteristics and a new nonlinear parameter. Based on the very high-cycle fatigue testing results for a 6N01 aluminum alloy welded joint, the relationship between the amplitude of the second-order harmonic and fatigue cycling has been established. The nonlinear ultrasonic system test results show that the amplitude of the second-order harmonic increases at the early fatigue stage, with further increase in cyclic loading until reaching a peak. Metallographic examinations show that a fatigue crack will nucleate in the weld joint in the stage as the amplitude reaches the peak value. Finally, theoretical and experimental results confirm that the amplitude of the second-order harmonic is useful for assessing the fatigue life of a 6N01 aluminum alloy welded joint.