bluuebunny/crossref_metadata_2025 huggingface dataset:
Factores clave del éxito en las empresas que practican márquetin social
Authors: Lin Mong-Mei
Published: May 2014

A través del márquetin social, las empresas podrían crear valores de multiservicio para la satisfacción del cliente, para incrementar los beneficios de la empresa y para beneficiar a la sociedad. La construcción de una Cadena de Valor de Servicio Social positiva para conseguir una gestión mental en el márquetin reforzaría las principales ventajas competitivas de una empresa, realzaría servicios de alta calidad y llevaría a la empresa a una dirección sostenible. Mediante el Método Delphi, se administra un cuestionario para evaluar los factores clave del éxito en empresas que practican el márquetin social. Se seleccionó a jefes y empleados del Grupo de Plásticos de Formosa para que cumplimentaran 200 cuestionarios. Se consiguió un total de 133 copias válidas, con una tasa de recuperación del 67%. A tenor de la influencia total de cada uno de los factores de éxito clave en empresas que practican el márquetin social, cabe concluir de forma resumida lo siguiente. 1. Los criterios de evaluación de las características organizativas se ordenan de la siguiente manera: Estructura Intrínseca, Entorno Interno, Eficiencia en Costes, Ventaja Organizativa, Debilidad Organizativa e Inspiración. 2. Los criterios de evaluación del contexto externo se ordenan así: Recursos Informativos, Oportunidades Contextuales y Amenazas Contextuales. 3. El orden de los criterios de evaluación de la estrategia de márquetin es el siguiente: Medios de comunicación Apropiados, Objetivos, Selección de mercados, la Respuesta de mercado y Cambios de Conducta. 4. Los criterios de evaluación de la orientación de procesos son los siguientes: Seguimiento de Ajustes, Sistemas de Feedback, Resultado de la Operación y Procesos de Operación.
Security of ISES Measureserver® Module for Remote Experiments against Malign Attacks
Authors: Gerža Michal , Schauer František , Jašek Roman
Published: May 2014

This paper focuses on the security of the remote laboratories, formed by remote experiments, against malign attacks. Surprisingly, in spite of the fact the remote laboratories have been existing for at least three decades, virtually no attention has been devoted to this vital subject. Specifically, the paper deals with the issues related to diverse attacks on the Measureserver® module, which is the basic unit of the ISES (Internet School Experimental System), based remote experiments, accessed by clients via web pages by common browsers. Such laboratories are sometimes called e-laboratories. In the introduction the basic features, principles and state of the art of this new ICT (Information and Communication Technologies) tool is described. The following chapter describes general security risks of remote laboratories for their software, hardware and as well as their specific risks. Next, the possible and existing attacks are analyzed for the Measureserver module. Finally, the suggestions for adequate security software and hardware solutions are outlined to secure the module.
A Case on Teaching Critical Thinking and Argument Mapping in a Teacher Education Context
Authors: Oral Yasemin
Published: May 2014

This chapter is based on the classroom work of a course on critical thinking designed as part of a pre-service teacher education program in English language teaching at a large-size Turkish state university. With its dual focus on both modernist and postmodern approaches to critical thinking, the course offers scope for classwork that concentrates on the skills to identify the parts and structure of arguments. To this end, argument mapping has been utilized to enhance understanding of the components of arguments and to facilitate the analysis of arguments. This chapter seeks to illustrate the materials and activities used when argument maps have been constructed during the class sessions. Furthermore, drawing from the data gathered from students' journal entries, I argue for a high interplay of the perceived efficacy of argument mapping with the content, length, and complexity of arguments as well as the anxiety evoked by these factors.
Concept Maps as Replacements of Written Essays in Efficient Assessment of Complex Medical Knowledge
Authors: Gomez Gloria , Griffiths Robin , Navathe Pooshan
Published: May 2014

Marking efficiency and timely student feedback are two aspects of assessment that may be greatly improved with concept maps (cmaps), if student learning style preference for more traditional approaches can be overcome. A semester-long exploratory case study was designed and performed in a distance aviation medicine course. This involved participant observations, interviews, and task analysis to investigate cmaps' claimed advantages for meaningful learning. The results showed that cmaps could be suitable replacements of written essays in the assessment of complex medical conceptual knowledge. Both present similar strengths and weaknesses; however, cmaps are faster to mark, and quickly reveal student understanding of a particular topic. The discussion of results is informed by relevant literature on concept mapping (cmapping) in medical education, assessment for deep understanding, and learning styles. This research can benefit online postgraduate education programmes searching for alternatives to improve the assessment process.
Talmud Diagrams
Authors: Ury Israel
Published: May 2014

The Talmud, as the basic source of Jewish law and thought, continues to receive the attention of scholars and students from a wide age group. Study of the Talmud is complicated by its complex and involved legal arguments. Talmud Diagrams are designed to be easy to read graphical representations of the logic of the Talmud that aid its comprehension and retention. In particular, Talmud Diagrams are maps of legal opinions that consist of rulings on a set of related cases. Passages in the Talmud are represented by a series of Talmud Diagrams that portray the evolution of the legal opinions, challenges, and resolutions. The principle of a fortiori is embedded within the structure and formation rules of Talmud Diagrams, allowing the use of Talmud Diagrams to be extended to other legal systems where a fortiori applies.
Freedom of Information and Records Management
Authors: Sebina Peter Mazebe II Mothataesi , Grand Balulwami
Published: May 2014

The adoption of e-Government programmes in Africa have been occasioned by the desire to improve public service delivery and to further enhance the government-citizen relationship through provision of access to information. Key to e-Government is information- its creation, management, and uploading onto a defined platform; its consistent updating and archiving; and its access by citizens irrespective of their level of education, social standing, or geographical location. The main outcome of e-Government is enhanced accountability of the governance process. Accountability in e-Government is a value-add to the government-citizen relationship in that citizens become assured that government will account to them as collaborators in the governance process. The reality in Africa is that the adoption of e-Government on its own is unlikely to yield the needed accountability mechanism. This chapter argues that an e-Government programme in Africa, supported by Freedom of Information and records management will result in governance which is both accountable and integral.
E-Government Development in Botswana
Authors: Moahi Kgomotso Hildegard
Published: May 2014

Botswana is in the process of developing and implementing e-Government for its population in an effort to enhance and improve service delivery. In order to achieve that, a significant number of interventions have been put in place on both the supply and demand sides of e-Government. Using literature and document review, this conceptual chapter highlights the major interventions in place to encourage development of e-Government. Specifically, the chapter explores the role of libraries in cementing the use and growth of e-Government in Botswana. The chapter posits that libraries have a cardinal role to play in successful implementation of e-Government, and must therefore be taken into serious account.
Strategic Networking Behavior of SMEs
Authors: Vasilska Maria , Kereziev Iliya , Ivanova Yordanka
Published: May 2014

Strategic networking behavior of SMEs is an issue that has not yet been thoroughly studied in the context of emerging market economies in Eastern Europe. No doubt, through strategic networking, SMEs could gain access to valuable resources – information, know-how, technologies, finance, etc., needed for strategy development, and building and maintaining competitive advantages. In addition, the networking of Bulgarian firms operating in a limited domestic market can be viewed as a tool for gaining access to external markets. On the other hand, intensive collaboration and networking creates problems and challenges for the SMEs and places new requirements to their strategic management. Therefore, this chapter draws upon the data and results of three researches which investigated strategic networking behavior of Bulgarian SMEs in order to reveal the specific benefits and challenges of SMEs involved in networks and to examine the impact of networking activities on SMEs strategic development. Finally, recommendations for the strategic networking behavior of Eastern European SMEs are formulated with a view to improve their results from networking and hence their competitiveness.
Securing Remote Obstetrics Monitoring Systems
Authors: Tan Chiu C. , Korostelev Michael , Bai Li , Mastrogiannis Dimitrios S. , Wu Jie
Published: May 2014

Reports from many countries describe remote obstetrics monitoring systems as a means of improving the quality of prenatal care. The next generation of remote obstetrics monitoring systems incorporate off-the-shelf equipment like commercial smartphones into their design, to not only reduce the cost of the monitoring equipment, but also to allow for greater flexibility by letting the patient perform monitoring herself, in the comfort of her own home. In this paper, the authors analyzed the security protections of recently proposed monitoring systems and proposed recommendations to improve the security of these systems.
Framework Design and Case Study for Privacy-Preserving Medical Data Publishing
Authors: Niu Yu , Yang Ji-Jiang , Wang Qing
Published: May 2014

With the pervasive using of Electronic Medical Records (EMR) and telemedicine technologies, more and more digital healthcare data are accumulated from multiple sources. As healthcare data is valuable for both commercial and scientific research, the demand of sharing healthcare data has been growing rapidly. Nevertheless, health care data normally contains a large amount of personal information, and sharing them directly would bring huge threaten to the patient privacy. This paper proposes a privacy preserving framework for medical data sharing with the view of practical application. The framework focuses on three key issues of privacy protection during the data sharing, which are privacy definition/detection, privacy policy management, and privacy preserving data publishing. A case study for Chinese Electronic Medical Record (ERM) publishing with privacy preserving is implemented based on the proposed framework. Specific Chinese free text EMR segmentation, Protected Health Information (PHI) extraction, and K-anonymity PHI anonymous algorithms are proposed in each component. The real-life data from hospitals are used to evaluate the performance of the proposed framework and system.
The Application of Intelligent Keywords to Patient Adherence Management System
Authors: Yang Yin-Pin , Lai Tsai-Ya
Published: May 2014

Health behavior change is the key challenge for healthcare intervention adherence management. For each treatment planning, patient adherence can be managed, audited, and improved by the Patient Adherence Management System applying Intelligent Keyword (PAMSIK) featuring the use of intelligent keywords, which has been design to navigate users to the target in-time knowledge and also leverage the collective power – peer learning to encourage patients. Three major components of PAMSIK are: an autonomous, intelligent, friendly User Behavior Collector to identify patient's personal adherence problems, a Patient Similarity Analyzer to dynamically cluster peers, and a Cure Service Dispatcher to recommend suitable cures and thus deliver prompt services and in-time contents to users.
Implementing a Cohesive Zone Interface in a Diamond-Coated Tool for 2D Cutting Simulations
Authors: Qin Feng , Chou Kevin
Published: May 2014

The interface properties and deposition residual stresses may have significant effects on the diamond-coated tool performance. However, it is still not fully understood how the interface mechanical behavior and deposition residual stress together influence the thermo-mechanical behavior of a diamond-coated tool during machining. In this study, a two-dimensional (2D) cutting simulation incorporating both deposition residual stresses and an interface cohesive zone model has been developed to demonstrate the feasibility of evaluating coating delamination of a diamond-coated tool during cutting. It has been shown that even the residual deposition stresses alone may result in failure initiations in the cohesive zone (i.e., the interface). In addition, the study further demonstrates the implementation of a cohesive zone interface in a diamond-coated tool in 2D cutting simulation. An example of cohesive failures occurred during the cutting simulation is presented. The result further shows that a larger uncut chip thickness will result in cohesive delamination of the coating-substrate interface during cutting.
FE Modeling for Load Distribution Analysis of Multi-Bolt Composite Joints
Authors: Xu Zhi Xiang
Published: May 2014

Multi-bolt composite joints are widely used in the primary structures because of their advantages of high reliability, load carrying capability, and maintainability. Load distribution analyses, as the precondition of strength analysis and design of multi-bolt composite joints, have attracted extensive attention over decades. The conventional 2D FEM, new 2D FEM and 3D FEM were established to analyze the load distribution of a typical single-lap three-bolt composite joint. The effect of friction on the load distribution results of 3D FEM was investigated. Furthermore, the load distribution of the joint was examined by using a theoretical spring model and load distribution experiments. Based on the investigation of experimental and numerical results, the load distribution character of single-lap three-bolt composite joint was obtained, and the suitability of different FE models was verified.
Noise Transfer Function Refinement of Commercial Vehicle Cab Based on the Vibro-Acoustic Model
Authors: Gao Yin Han , Wang Zhi Bo , Liang Jie , Zhang Li Tong , Liu Ying Jie , Jiang Wen Jun
Published: May 2014

The TPA method has gradually developed into a mature approach to solve the internal noise problem of vehicles in recent years. Among the excitation transfer path from excitation to the noise at the target point, the noise transfer function is an important path. The noise transfer function is an inherent property of the commercial vehicle cab like the modes. When noise transfer function is low; the noise caused by the vibration transformed from the suspension is relatively low, which will be great help for the comfort of the cab.
A vibro-acoustic model of some commercial vehicle cab has been built in this research, and the low frequency region noise transfer function from the mount points to the driver's ears has been simulated. From the comparison of the numerical result and the relevant test result, the accuracy of the simulation model has been proved. For the sensitive frequencies, the vibro-acoustic modes have larger vibration on some thin plates, which has been proved to be the reason for the peak for the noise transfer function. In order to reduce the noise transfer function, damping materials were applied to the sensitive thin plates, the modification effect proved to be content in the real working condition.
Ball Valve Seat Design Method Based on Finite Element Analysis and Calculation
Authors: Peng Yan , Zong Liang Yu , Hao Liu Feng , Li Qi Yang
Published: May 2014

The face of the valve seat sealing surface design, the finite element analysis and calculation of ball valve seat sealing surface and angle of the design method is studied. Through 3D CAD technology for ball valve design, guide 3D design model to finite element analysis software to calculate ,reveal the sealing load distribution of pressure in the valve seat sealing surface, sealing pressure values are obtained, through the valve seat sealing surface design Angle analysis, to obtain the optimal value of sealing surface angle.
The Strength of Laser Welded Web-Core Steel Sandwich Plates
Authors: Jiang Xiao Xia , Zhu Liang , Qiao Ji Sen , Wu Yi Xiong , Li Zhu Guo , Chen Jian Hong
Published: May 2014

All steel laser welded sandwich plates have found their position in the marine and land vehicles. To implement such design accurately, knowledge about its strength properties and the influence of laser weld dimensions on strength is necessary. In this paper, the over-hanging three point bending tests were conducted on the laser welded web-core steel sandwich plate with various weld dimensions by self-designed device, together with the finite element simulations. The results show that the joint is formed on the first plastic hinge when the load is no longer a linear relationship with the deflection, and the joint cracking when the load reaches the maximum bearing capacity of sandwich plate. The joint yield load and the maximum bearing capacity of the sandwich plates increased with the increasing of weld width. Meanwhile, the mode of failure of sandwich plates also changed: When the weld width is smaller, the mode of failure is joint yield, When the weld width is greater than 3mm, the mode of failure is the combination of partial joint yield, face plate and core plate local yield, while the face plate and core plate yield exists in the whole weld joint. It is necessary to consider the weld width in the design and evaluation of the strength of the laser welded web-core sandwich plate.
Water Resources Allocation of China Based on the Projection Pursuit Cluster
Authors: Zhou Ao Jun
Published: May 2014

Taking account of the economy, geography and ecological factors,based on the projection pursuit cluster, an optimization model for water-distributing weight is introduced with the eight factors (gross domestic product, industrial production, irrigation area, urban population, area of land, grosspopulation, cultivated land area and total water resources).Then the optimalwater-distributing weight which will promote sustainable development is worked out by genetic algorithm.
An Adaptive Time Delay Alignment Technique Based on Equalizer Taps in a Sensor Array
Authors: Tu Qi Hui , Shen Cai Yao , Yu Hong Yi , Hu Yun Peng
Published: May 2014

In the wireless sensor network, every node is energy and resource limited and the received signal is weak, which requires less complexity and low computation signal combination algorithm to improve the signal-to-noise ratio (SNR) of the combined output signal. Considering the computation and time-varying delay, this paper proposes an adaptive feedback time-delay alignment method based on equalizer taps to decrease the SNR loss caused by time-delay difference. The relationship between the equalizer taps and time-delay difference is derived according to the Nyquist first criterion and the gradient descent algorithm is adopted to iteratively adjust the time delay of one antenna signal. The numerical results show that the algorithm can almost eliminate the time difference and the SNR loss decreases. The bit error rate (BER) performance is obviously improved.
The Theoretical Analysis of Cylinder Screening Machine Based on the Method of Mogensen Screening and the Design of Intelligent PLC Control
Authors: Gu Li Zhi , Wang Jiao Tao , Du Wei Wen , Huang Yan Hua , Gu Li Zhi
Published: May 2014

The process of the single particle through screening is researched theoretically with Mogensen screening principle. The screened particles are divided into "particle easy to screen" and "particle difficult to screen" according to the relative size and shape. Systematically analyze the factors that affect the efficiency of cylinder screening machine—the characteristics of materials’ dimension, shape features, the movement of sieve, and sieve surface obliquity, in order to realize the nuts and kinds of nuts to be graded effectively according to the size and shape. PLC intelligent control is adopted into cylinder screening machine, through the real-time detection of the speed of the cylinder at all levels and the chain transfer between the cylinders, to logically estimate the possible faults in the screening process, improving the degree of automation and reliability and safety of the equipment operation.
Active Disturbance Rejection Control in Airborne Direct Drive Electro Mechanical Actuator Application
Authors: Liu He Song , Fu Yong Ling , Chen Juan , Chen Hui
Published: May 2014

A novel active disturbance rejection control (ADRC) strategy is presented to improve position control performance of airborne direct drive electro-mechanical actuator (EMA). To begin with, kinematics model of the direct drive EMA is deduced for simulation benefits. Then, an ADRC controller is designed to implement the position control. Finally, simulation work is put forward to verify the steady-state precision, dynamic performance and load disturbance rejection ability, accounting for over-running load. The results verify that the ADRC-based EMA servo system is fast, precise, of no overshoot and strongly robust to load disturbance.
Improved Position Control of Electro Mechanical Actuator Utilizing Optimal Current Trajectory Control
Authors: Liu He Song , Fu Yong Ling , Chen Juan , Chen Hui
Published: May 2014

Electro mechanical actuator (EMA) is an important type of power-by-wire (PBW) actuator. The dynamic performance of EMA is a key issue especially when it is mounted on a fighter aircraft. Generally, the EMA adopts permanent magnet synchronous motor (PMSM) as the drive unit. It is a position controlled cascade system with an inner current control loop. This study focuses on the current control loop and proposes a scheme which utilizes optimal current trajectory control to exploit the inherent torque capability of the motor. Compared with traditional current control, i.e. id=0 strategy, the torque capability of the motor is maximized and the speed range is expanded. This directly improves the EMA dynamic performance. Faster transient process is demonstrated experimentally, which verifies the efficiency of the proposed scheme.
Improve Peach: Making Network Protocol Fuzz Testing more Precisely
Authors: Zhang Hua , Zhang Zhao , Tang Wen
Published: May 2014

Peach is an indispensable tool for network security experts, but, it is not perfect in the coarse controlling granularity. This paper analyzes the core code of Peach and makes improvements of Peach in three aspects: 1) applying different Mutators to test different fields in PDU; 2) starting a fuzz test at any test case according to a config.xml file; 3) executing the specified number of test cases in each test. These contributions make fuzz testing like software debugging, and locate a network protocol implementation's bug triggered by which test case more precisely with less time and less test cases than ever before. This paper also adds a replaying test scenario to Peach based on our contributions. Experimental results demonstrate that the features this paper improved to Peach could save lots of time with lower costs when applying Peach to test protocol implementations.
Effect of Tensile Twinning on Low Temperature Shear Formability of Mg-3Al-1Zn Alloy
Authors: Dogan Ebubekir , Vaughan Matthew W. , Karaman Ibrahim
Published: May 2014

Mg-3Al-1Zn (AZ31) alloy samples with different starting textures have been processed using Equal Channel Angular Processing (ECAP) at 150°C and 200°C. The common temperature limit for ECAP of wrought AZ31 alloys has been reduced from 200°C to 150°C by suppressing tensile twinning activity. Twinning activity was reduced by either changing the starting texture or increasing the temperature. A crystal plasticity model was utilized to gain a better insight into the operating deformation mechanisms during ECAP. Suppression of tensile twinning and pronounced prismatic slip activity resulted in a crack-free, homogeneous deformation at 150°C. In addition, twinning, when exists, was shown to have a significant effect on the promotion of DRX and shear band formation.
In Situ Synchrotron Diffraction Studies on Hot Deformation of Austenite in a High Strength Quenched and Tempered Structural Steel
Authors: Dutta R.K. , Huizenga R.M. , Amirthalingam M. , Gao H. , King A. , Hermans M.J.M. , Richardson I.M.
Published: May 2014

The effect of plastic deformation of austenite at elevated temperatures on the kinetics ofphase transformations during continuous cooling was studied in a high strength quenched and tem-pered structural steel S690QL1 (Fe-0.16C-0.2Si-0.87Mn-0.33Cr-0.21Mo (wt.%)) by means of in-situsynchrotron diffraction. The steel was heated to 900 C (above Ac3) in the austenite region and elon-gated by 6% followed by quenching to room temperature. Time-temperature-load resolved 2D syn-chrotron diffraction patterns were recorded and used to calculate the local d-spacings between latticeplanes. The plane specific diffraction elastic constants of austenite at 900 C in the steel were deter-mined from the local d-spacings. The effect of the deformation of austenite on the phase transforma-tion kinetics was studied. The evolution of lattice parameters and the phase fraction of the bcc phasesduring the quenching process were calculated.The calculated plane specific elastic constants of austenite at 900 C varied between 32 GPa to140 GPa for the different fhklg reflections of austenite. The deformation of austenite at 900 C re-sulted in the formation of a mixture of 38 % bainite, 59 % martensite and 3 % retained austenite afterquenching to room temperature. Without hot deformation, austenite transformed to 9 % bainite and88 % martensite with 3 % retained austenite. The presence of the bainitic and the martensitic phaseswas observed fromthe change in the slopes of the lattice parameters of the bcc phase during quenchingand confirmed by microscopy.
Corrosion Behaviour of AISI 304 Stainless Steel with Solar Salt Heat Transfer Fluid
Authors: Ahmed Omar , Zhou Le , Mohajeri Nahid , Sohn Yong Ho
Published: May 2014

In an effort to understand the compatibility between the heat transfer medium and the structural materials used in concentrated solar power plants, the corrosion behavior of AISI 304 stainless steel (18 wt.% Cr, 8 wt.% Ni) in a molten solar salt mixture (53 wt. % KNO3, 40 wt. % NaNO2,7 wt. % NaNO3) has been investigated. The 304 stainless steel coupon samples were fully immersed and isothermally exposed to solar salt at 530°C for 250, 500, and 750 hours in air. X-ray diffraction and scanning electron microscopy with X-ray energy-dispersive spectroscopy were employed to examine the extent of corrosion and identify the corrosion products. Oxides of iron were found to be the primary corrosion products in the presence of the molten alkali nitrates-nitrite salt mixture because of the dissolution of the protective chromium oxide (Cr2O3) scale formed on 304 stainless steel coupons. The corrosion scale was uniform in thickness and chromium-iron oxide was found near the AISI 304. This indicates that the scale formed, particularly on the upper layer with presence of sodium-iron-oxide is protective, and forms an effective barrier against penetration of fused solar salt. By extrapolation, annual corrosion rate is estimated to reach 0.784 mils per year. Corrosion behavior of AISI 304 stainless steel is discussed in terms of thermodynamics and reaction paths.
Life Prediction of High-Temperature MCrAlY Coatings Based on Microstructural Observations
Authors: Eriksson Robert , Yuan Kang , Johansson Sten , Peng Ru Lin , Li Xin Hai
Published: May 2014

Thermal barrier coatings are commonly used in gas turbines for protection against high tem-perature and oxidation. Life prediction of oxidation protective coatingsmay be done bymicrostructure-based techniques such as -depletion based life criteria. In this study, a thermal barrier coating sys-tem, with an overlay NiCoCrAlY coating as bond coat, was oxidised up to 10000 h at 900 C. Themicrostructure was studied and related to Al depletion. It was found that a -depletion based lifecriterion could not be used for the studied coating composition and temperature as it would be tooconservative. A 0-depletion based model was instead suggested and supported by interdiffusion sim-ulation.
Evolution of Laves-Phase Particles in a Low Carbon 9%Cr Martensitic Steel during Creep at 650°C
Authors: Fedorova Irina , Belyakov Andrey , Kozlov Pavel , Skorobogatykh Vladimir , Schenkova Izabella , Kaibyshev Rustam
Published: May 2014

The evolution of microstructure in low carbon heat resistant steel of P92-type modified with 3%Co was examined during creep tests at 923K for 500, 1500, 6000 and 16000 hours. After tempering at 1023K (750°C), the steel was composed of martensite lath structure with numerous precipitates of MX-type carbonitrides and rare M23C6-type carbides. The structural changes during creep tests are characterized by an increase in the sizes of laths and second phase particles. Moreover, the Fe2W Laves-phase precipitates during long-term creep. The Laves-phase particles grow accordingly to power-law relationship of creep time.
X-Ray Residual Stress Analysis of Stainless Steel Using cosα Method
Authors: Sasaki Toshihiko , Koda Kei , Fujimoto Yohei , Ejiri Shoichi , Suzuki Tamaki , Kobayashi Yuichi
Published: May 2014

This paper shows X-ray residual stress analysis of stainless steel using 2-dimensional detection method. The 2-dimensional detection method of X-ray stress measurement will determine stress by conducting a 2-dimensional detecting of a Debye ring and analyzing the image data. The basic of typical austenitic stainless steel (JIS SUS304) was studied in this study, considering the fact that, at certain power plants, maintenance takes place to prevent stress corrosion cracking by adding compressive residual stress to the structure..
Application of Texture Analysis for Optimizing Thermo-Mechanical Treatment of a High Mn TWIP Steel
Authors: Haase Christian , Barrales-Mora Luis Antonio , Molodov Dmitri A. , Gottstein Günter
Published: May 2014

A recently introduced processing route consisting of cold rolling and recovery annealing allows the production of TWIP steels with high yield strength along with appreciable uniform elongation due to the thermal stability of mechanically induced nanoscale twins. A wide range of strength-ductility combinations was obtained using recovery and recrystallization annealing of 30%, 40%, and 50% cold-rolled Fe-23Mn-1.5Al-0.3C TWIP steel. Texture measurement during cold rolling and annealing was proven to be a suitable tool to determine the optimal deformation degree and annealing time for this processing method. As a consequence, texture analysis can be used to predict the final materials properties.
Structural Analysis of Shape Memory Gel
Authors: Kabir M. Hasnat , Makino Masato , Gong Jin , Furukawa Hidemitsu
Published: May 2014

The determination of structural properties of a material is important before its practical application. The analysis data provide us some information whether the material is suitable for application or not. The prospective applications of soft and wet materials explore the new era in the material science as an industrial material especially for medical applications. Shape memory gels (SMGs) are one kind of unique soft and wet materials having shape recovery property which is suitable for medical application such as bandages for broken bones or making optical lens and so on. In the present study, scanning microscopic light scattering (SMILS) is used to characterize the internal structure of shape memory gels. It is observed that the SMGs are transparent at room temperature, mechanically elastic and ductile as well as thermoresponsive despite the high water contents. We confirm the mesh size in nanometer scale of the internal network structure and the critical behavior of the SMG by dynamic light scattering (DLS). The mechanical properties also have been characterized by dynamic mechanical analysis (DMA).
Martensitic Transformation and Related Properties of AuTi-FeTi Pseudobinary Alloys
Authors: Aoki Taku , Tahara Masaki , Goto Kenji , Yamabe-Mitarai Yoko , Kanetaka Hiroyasu , Inamura Tomonari , Hosoda Hideki
Published: May 2014

The effects of Fe addition on martensitic transformation and mechanical properties of AuTi were investigated in this study. It was found that B2 parent phase is stabilized by the Fe addition and that AuTi can contain at least 20mol%Fe. The lattice deformation strain evaluated from θ-2θ X-ray diffraction analysis (XRD) is not significantly changed by the Fe addition. The decrease in Ms evaluated by differential scanning calorimetry (DSC) is-40K/mol%Fe. Tensile tests revealed that, with increasing Fe content, the yield stress decreases up to about 13mol%Fe, largely increases up to 15mol%Fe and then decreases gradually. By taking into account XRD and DSC results, these behaviors are judged to correspond to reorientation of martensite variants, stress induced martensitic transformation and slip deformation of parent phase, respectively. The values of dσSIMT/dCFe and dσSIMT/dT are evaluated to be-170MPa/mol%Fe and-4.3MPa/K, respectively. The elongation is degraded with increasing Fe content from 8% in AuTi (0mol%Fe, martensite phase) to 2% in AuTi-20mol%Fe (parent phase) depending on the apparent phase.
Effect of Process Parameters on Friction Surfaced Coating Dimensions
Authors: Akram Javed , Kalvala Prasad Rao , Misra Mano
Published: May 2014

Friction surfacing is a novel technology to build corrosion and wear resistant coatings and build functionally graded metallic layers. In this work, the coating dimensions as affected by process parameters and high temperature strength of consumable rods have been compared. Friction stir welding equipment, RM-1 model procured from MTI was used. Carbon steel, austenitic stainless steel and Ni-based alloy coatings were deposited. Following process parameter ranges were used: rotational speed: 1000-2000 RPM, feed rate: 50-150 mm/min and axial load: 3-12 kN. Results showed that the coating width and thickness decreased with a) increased magnitude of the process parameters used and b) increased high temperature strength of the consumable rod.
Effect of Precipitation on Texture Evolution during Dynamic Recrystallization in Mg-Al-Sn Alloys
Authors: Kabir Abu Syed Humaun , Su Jing , Sanjari Mehdi , Jung In Ho , Yue Stephen
Published: May 2014

In common magnesium alloys, recrystallization is usually not accompanied with a noticeable change of deformation texture resulting in, strong mechanical anisotropy. The aim of this work is to investigate the effect of dynamic or strain induced precipitates on texture evolution during hot deformation of Mg-Al-Sn alloys. Mg-Al-Sn alloys have been designed using thermodynamic modeling software, FactSage, based on forming precipitates at hot deformation temperatures. Two alloys have been chosen in a way that one forms precipitates during the hot deformation process, another does not at a certain temperature. Uniaxial compression has been introduced at different strain rates at this elevated temperature to simulate the hot deformation behaviour. Two alloys have been compared in terms of the intensity of basal texture. It was found that the formation of dynamic precipitates during deformation weakens the texture compared to the case where no precipitates were formed.
Effects of Cooling Rate on Impact Toughness of an Ultrahigh-Strength TRIP-Aided Martensitic Steel
Authors: Kobayashi Junya , Nakajima Yuji , Sugimoto Koh Ichi
Published: May 2014

The effects of variations in the rate of post-austenitization cooling of a 0.2%C-1.5%Si-1.5%Mn-1.0%Cr-0.2%Mo-1.5%Ni-0.05%Nb (mass%) transformation-induced plasticity (TRIP)-aided steel with a lath martensite structure matrix on the Charpy impact toughness were investigated, with the aim of improving the material properties for automotive body applications. When cooled at 1.2°C/s after austenitization, the TRIP-aided steel showed a higher upper-shelf Charpy impact absorbed value (90 J/cm2) and a lower ductile-brittle fracture appearance transition temperature (−126°C), compared with the values determined (82 J/cm2, −98°C) for steel cooled at 53.5°C/s. The lower cooling rate yielded a higher volume fraction and carbon concentration of metastable retained austenite, finer martensite-austenite constituents, and a lower carbide fraction in the wide lath martensite structure in the TRIP-aided steel. These improved microstructural characteristics resulted in superior impact toughness.
Relationship between Strength and Grain Size of Friction Stir Processed and Annealed High Purity Aluminum
Authors: Kobayashi Sho , Kawakatsu Tomo , Takigawa Yorinobu , Uesugi Tokuteru , Higashi Kenji
Published: May 2014

A relationship between yield stress and grain size was examined in FSP-ed and annealed 5N-Al (99.9996% purity) in order to reveal the relationship on materials with equal chemical composition, because the large positive deviations of yield stress from the Hall–Petch relation obtained by plots with coarse grain size were reported in the fine grain sizes with SPD processed and we focused on amount of impurities during SPD processing about this phenomenon. The purity of FSP-ed samples on this study were 99.9988% Al (Fe +8at.ppm). Annealing this sample at various temperatures, the relationship between yield stress and grain sizes was obtained on materials with equal chemical composition. However, the yield stress of sample as FSP-ed is higher than that following Hall-Petch relation obtained by subsequently annealed samples plots. As a result, the positive deviation is occurred by factors other than the impurities.
Numerical Analysis of Gas Tungsten Arc Welding with a Constricted Nozzle for Butt Joint of Thin-Sheet Metals
Authors: Konishi Kyohei , Tanaka Manabu , Murata Akihisa , Murata Tadasuke
Published: May 2014

GTA (Gas Tungsten Arc) welding process has been studied as a higher level welding process. The “GTA welding process with constricted nozzle” is one of new welding processes [1]. In this new process, arc stiffness is greatly improved by attaching an additional gas nozzle which is called “constricted nozzle” inside the shielding gas nozzle. The design of a constricted nozzle is shown in Figure 1. With this new process, a butt joint of thin-sheet metals can be achieved although that is difficult with a conventional GTA welding process. In this study, numerical simulation is conducted to understand phenomena of arc plasma in a GTA welding process with a constricted nozzle scientifically.
The Influence of Morphology on the Hydrogen Storage Properties of Magnesium Based Materials Processed by Cold Rolling
Authors: Lang Julien , Asselli Alexandre , Hebert Nicolas , Huot Jacques
Published: May 2014

In this communication we report the effect of macro and microstructure on the hydrogen storage properties of magnesium based materials. Magnesium hydride is an attractive material for hydrogen storage applications since it has a high hydrogen volumetric density. Furthermore, the high enthalpy of hydride formation makes it attractive for thermal energy storage applications. Besides, magnesium is an abundant and low cost material. However, the Mg/MgH2 system requires high operating temperatures due to its thermodynamic stability and slow hydrogen absorption and desorption kinetics. Magnesium’s first hydrogenation is a very long and costly process. This work aims to ameliorate this process which would effectively reduce the cost of MgH2.
Commercial pure magnesium samples were processed by cold rolling. After processing, the samples presented limited hydrogen absorption due to their small surface area to volume ratio. To overcome this problem the samples were then reduced to powder using a bastard file. The samples were characterized by scanning electron microscopy and presented different morphology. Hydrogen storage properties and morphology are discussed and correlated. Results show an important improvement on the hydrogen absorption and desorption kinetics for the comminuted samples.
Description of Surface Energy Anisotropy for BCC Metals
Authors: Luo Y.K. , Qin Rong Shan
Published: May 2014

Surface energy anisotropy (SEA) has long been a hot topic in interface science as it has an important role in the interface/surface behaviours for crystalline phases. Most studies aim to determine the numerical values of the anisotropic surface energy in some particular orientations, but few investigate the whole orientation-dependent trend, or the morphology of the polar plot. The present work propose descriptions for SEA of both body centred cubic (BCC) and face centred cubic (FCC) metals by considering the interactions between an atom and its 1st, 2nd and 3rd nearest neighbouring (NN) atoms. The expression makes use of only three coefficients K1, K2 and K3 which are correspondent to the contribution of 1st, 2nd and 3rd NN interactions respectively. This allows estimation of surface energy for all crystallographic orientations if the values for (111), (100) and (110) orientations are provided. Matching of our model with modified analytical embedded-atom method (MAEAM) results demonstrates less than 0.5% average relative error. We also construct the polar plots of BCC metals based on our model and compare them with some other models.
Effect of Composition and Thermo-Mechanical Processing on Microstructure Development in Ni-30Fe-Nb-C Model Alloys
Authors: Mannan Parvez , Kostryzhev Andrii G. , Pereloma Elena V.
Published: May 2014

The unavoidable phase transformation upon cooling makes a direct observation of austenite microstructure impossible. One of the methods to investigate the high temperature condition of austenite is to use a model alloy, which would not transform to martensite on quenching. In the present work the recrystallisation and grain growth of austenite during thermo-mechanical processing (TMP) were studied for three Ni-30Fe-Nb-C alloys containing 0.33, 0.85 and 1.42 wt% Nb. The austenite microstructures were characterised using optical and scanning electron microscopy, and energy dispersive X-ray spectroscopy. The austenite recrystallisation kinetics was investigated with respect to the precipitate distribution variations. A relative strength of the grain boundary pinning effect from solute Nb and precipitated particles is discussed.
High Tensile Ductility in Electrodeposited Bulk Nanocrystalline Ni–W Alloys
Authors: Matsui Isao , Takigawa Yorinobu , Higashi Kenji
Published: May 2014

Bulk nanocrystalline Ni–W alloys were electrodeposited from a sulfamate bath that contained saccharin sodium as a gloss agent, and propionic acid and sodium gluconate as a complexing agent (SPG bath) to understand the tensile behavior. SPG bath with 1.0 and 5.0 g/L saccharin sodium at 45 ºC produced the bulk specimens with W content of 3.4 and 1.5 at.%, respectively. The electrodeposited alloys had a nanocrystalline structure with grain sizes of approximately 20 nm and a stronger (111) texture. The bulk nanocrystalline Ni–3.4 at.%W alloys deposited from an SPG bath with 1.0 g/L saccharin sodium exhibited a tensile strength of 1.6 GPa and tensile ductility of 1.8%. The bulk nanocrystalline Ni–1.5 at.%W alloys deposited from an SPG bath with 5.0 g/L saccharin sodium exhibited a tensile strength of 1.4 GPa and tensile ductility of 1.7%. The bulk nanocrystalline Ni–W alloys with a stronger (111) texture showed high strength and low plasticity.
Crystallographic Features of the ν Phase in the Mn-Si Binary Alloy System
Authors: Nakayama Kei , Yabu Shouhei , Mizuno Takashi , Koyama Yasumasa
Published: May 2014

In the Mn-Si alloy system, there is the intermetallic-compound ν phase around Mn-18at.%Si. Its crystal structure called the ν structure has been reported to involve complex coordination polyhedra with coordination numbers (CN’s) 12, 14, and others. To clarify whether one of these polyhedra can be identified as a structural unit or not in the ν structure, we have investigated the crystallographic features of the (R → R + ν) reaction in Mn-15at.%Si alloy samples by transmission electron microscopy. In Mn-15at.%Si samples obtained by cooling from the single R phase at a relatively fast cooling rate, metastable precipitates were found to be present in the R-structure matrix. Their notable feature is that each precipitate involves regions exhibiting characteristic electron diffraction patterns, which indicate the presence of metastable states, in addition to the initial amorphous and final ν states. Based on the careful analysis of these patterns, it was understood that the metastable states were directly associated with the formation of the ν structure, and that the formation started with the appearance of dodecagonal atomic columns. Because a dodecagonal column is characterized by a one-dimensional array of CN14 polyhedra, among the coordination polyhedra involved in the ν structure, a CN14 polyhedron can be identified as its structural unit.
A Review on Thermomechanical Models of Friction Stir Welding
Authors: Nourani Mohamadreza , Milani Abbas S. , Yannacopoulos Spiro
Published: May 2014

There are several reported thermomechanical models that can be used to predict friction stir welding (FSW) properties of different alloys. A major application of these models is the computation of material temperature, flow stress, strain rate and strain during the process and/or the resulting residual stress after the process. The models are normally applied to solve energy, mass and force equilibrium equations simultaneously using different numerical approaches. All of the validated models can be reliably used to optimize the FSW process parameters such as tool RPM and transverse speed. The brief review in this article is indented to summarize some of the most commonly used thermomechanical models of FSW along with their main characteristics namely; the Solid Mechanics-based models, Fluid Dynamics-based models, and hybrid/ multiphysics models.
On the Behavior of Yttria/Yttrium during Mechanical Alloying of a Fe - Y2O3 Model Alloy System
Authors: Ressel Gerald , Parz Peter , Fian Alexander , Holec David , Primig Sophie , Puff Werner , Leitner Harald , Clemens Helmut
Published: May 2014

Mechanical alloying (MA) is an established way to prepare nanocrystalline materials and metastable solutions of materials, which normally have no mutual solubility. This is also the case for oxide dispersion strengthened (ODS) steels with improved mechanical properties at elevated temperatures. It is known that a small addition of yttria (Y2O3) has a beneficial effect on high temperature strength and reduces the creep rate in mechanically alloyed ferritic steels by about six orders of magnitude. In this work we present an experimental study using atom probe tomography, X-ray photoelectron spectroscopy, and positron annihilation spectroscopy combined with first principles modeling focusing on the distribution and behavior of yttria in pure iron prepared by mechanical alloying. Atom probe tomography and X-ray photoelectron spectroscopy measurements as well as positron annihilation spectroscopy conducted on powder particles directly after milling have revealed that a predominantly fraction of the yttria powder dissolves in the iron matrix and Y atoms occupy convenient positions, such as vacancies or dislocations. This is supported by ab initio calculations demonstrating that the formation energy for Y substitutional defects in bcc-Fe is significantly lower in the close neighborhood of vacancies.