bluuebunny/crossref_metadata_2025 huggingface dataset:
La sécurité contre la peine
Authors: Garapon Antoine
Published: November 2016

Le terrorisme est combattu par des mesures sécuritaires qui visent à neutraliser les risques et qui sortent donc de la « mytho-logique » de la peine. Lorsqu’une peine n’est pas justifiée, mais qu’un danger est avéré, il faudrait pouvoir mettre en place une assistance civique transitoire.
The Euro Crisis’ Actors and their Roles
Authors: Hubé Nicolas , Salgado Susana , Puustinen Liina
Published: November 2016

Cette contribution observe le traitement journalistique des acteurs visibles lors de la première phase de résolution de la crise de l’euro (entre 2010 et 2012). Elle repose sur une étude de quarante journaux pris dans dix pays européens. Pour ce faire, nous avons pris au sérieux deux affirmations des littératures en communication politique et en European Studies  : d’une part, l’hypothèse de la personnalisation de l’écriture du politique et, de l’autre, celle d’un recul du processus d’européanisation, suggérant de facto que la crise de l’euro a contribué à accroitre le rôle et la place des gouvernements nationaux par rapport aux institutions communautaires et, certains pays plutôt que d’autres. Nos conclusions confirment ces hypothèses d’une couverture personnalisée des informations, dominées par les responsables politiques nationaux ainsi que par les experts économiques. Enfin nous abordons les raisons d’un tel cadrage de l’information et ses implications pour le processus d’intégration européenne, et en particulier pour l’absence d’un espace public européen.
La relación entre el uso de las TICs y la innovación de las MiPymes Mexicanas. Evidencia empírica del estado de Guanajuato, México.
Authors: Cuevas-Vargas Héctor , Aguilera Enríquez Luis , Citlalli López Torres Gabriela , González Adame Martha
Published: November 2016

Cette étude empirique visait à analyser la relation entre l'utilisation des TIC et de l'innovation des MPME industriels de Guanajuato, au Mexique. Les deux échelles utilisées ont été soumises à une analyse factorielle confirmatoire (AFC) de second ordre selon la méthode du maximum de vraisemblance, de fiabilité et de validité. Les résultats obtenus grâce à la modélisation par équation structurelle (SEM) à partir d'un échantillon de 288 MPME nous permettent de déduire qu'il ya suffisamment de preuves empiriques que l'utilisation des TIC a une influence positive et significative dans l'innovation de ce type d’entreprises.
Oportunidades y riesgos de las redes sociales en internet: el caso de empresas mexicanas
Authors: Güemez Regina Leal , Porras Salvador T.
Published: November 2016

L'utilisation des technologies de l'information (TI) est une stratégie utilisée par les organisations dans le cadre de leurs ressources pour effectuer des activités multiples et variées. Une application de ces technologies est les réseaux sociaux en ligne, qui sont devenus un phénomène mondial au cours des dernières années, avec un impact économique et social de grande dimension. Les réseaux sociaux ont considérablement évolué et passent d'un outil qui facilite seulement l'accès à l'information, à la pénétration dans de nombreuses façons dans les organisations, et génèrent simultanément de nouveaux modes de relations aux clients (Kaiser, Kröckel et Bodendorf 2013; Vaast et Kaganer 2013). L’objectif de cet article est double, d'abord de présenter un aperçu des sites de réseautage social au Mexique comme un outil que les entreprises devraient envisager dans le cadre de leur gestion stratégique, et d'autre part de contribuer à une meilleure compréhension de ce phénomène dans les entreprises mexicaines. La recherche consiste à analyser des sites web d'un groupe d'entreprises au Mexique, à partir de quoi, il apparaît une faible intégration des sites de réseautage social sur leurs sites. Le site de référence de réseautage social est Facebook (22%), suivie de Twitter (19%) et YouTube (8%). Les entreprises utilisent principalement ces réseaux dans le domaine du marketing pour la publicité sur Internet. Les résultats préliminaires nous permettent de continuer à travailler dans cette perspective afin de recueillir ultérieurement des informations directement auprès des entreprises pour analyser la stratégie liée à l'utilisation et à la gestion des sites de réseautage social.
La literatura en la ontología social de John Searle
Authors: Guijarro Lasheras Rodrigo
Published: November 2016

Estas páginas se proponen mostrar que el paradigma de la teoría de la construcción de la realidad social propuesto por John Searle en las últimas décadas permite derivar importantes elementos a la reflexión sobre literatura. La distinción entre «hechos sociales» y «hechos institucionales» supone ciertamente un sólido cimiento sobre el que articular una taxonomía de algunas de las principales aproximaciones a la ontología de la literatura. Un trabajo en esta línea de Vitor Guerreiro (2012) sobre filosofía de la música sirve de inspiración a la reflexión que se presenta aquí sobre el campo literario.
Historia, poesía y cotilleos. Cristina de Suecia en los Avisos de Barrionuevo
Authors: Arellano Ignacio
Published: November 2016

El artículo examina el modo en que aparece la figura de la reina Cristina de Suecia en los Avisos o noticias de Jerónimo de Barrionuevo, que va comentando los sucesos contemporáneos desde una perspectiva que podríamos llamar satírica, y que se relaciona con las convenciones propias del mismo género, pero también con la actitud intelectual y política del narrador.
De este modo se advierte que ciertos motivos se reservan para ciertos géneros: en este caso los chismes y cotilleos que no suelen aparecer en tratamientos propiamente literarios, forman el núcleo de los textos que definen en Barrionuevo la principal perspectiva con la que se evoca a Cristina. Así pues, no solo las prerrogativas de la poesía permiten modelar el tratamiento de los personajes históricos acudiendo a alteraciones de los hechos legitimadas por las teorías poéticas de la época; también los privilegios libérrimos del cotilleo adquieren un protagonismo especial, con un marcado predominio en Barrionuevo de la mirada misógina —que podría ser propia del relator o debida a la tendencia satírica de la misma categoría textual—.
Lugné-Poe e l’Œuvre simbolista
Authors: Altamura Giuliana
Published: November 2016

Il volume, nato dall’esigenza di rivalutare l’esperienza teatrale simbolista affrancandola dall’annoso pregiudizio sulla sua anti-teatralità, propone una ricostruzione storico-biografica della figura di Lugné-Poe – attore, regista, direttore, nonché principale animatore del teatro simbolista francese – e del suo teatro, l’Œuvre, per riconoscerne i tentativi di sperimentazione scenica.   Ripercorrendo la prima parte della vita del protagonista di questa affascinante stagione, lo studio traccia – con un criterio rigorosamente cronologico – un capitolo fondamentale della storia del teatro, affrontato finora quasi unicamente dal punto di vista della teoria, della poetica e dell’analisi testuale.   Partendo da un attento studio del contesto della nascita del teatro simbolista, la ricostruzione delle fortune alterne dell’Œuvre si sofferma, stagione per stagione, sui singoli spettacoli e sulla loro fortuna critica, oltre che sulle vicende interne delle relazioni umane e professionali intrattenute con artisti, scrittori, poeti, attori che per una ragione o per l’altra sfiorarono le vicende del teatro.   Il volume, frutto di un ampio lavoro di documentazione, ricontestualizza l’esperienza dell’Œuvre alla luce della consapevolezza contemporanea, rilevandone l’importanza per gli sviluppi delle avanguardie e dando inoltre maggiore spessore alla personalità di Lugné-Poe, da cui la scelta di un taglio biografico che, attraverso la ricostruzione di una vicenda professionale tanto ricca, arrivi a descrivere l’uomo, testimone e attore di un momento epocale di trasformazione.
Examining the Roles of Job Satisfaction and Organizational Commitment in the Global Workplace
Authors: Kasemsap Kijpokin
Published: November 2016

This chapter describes the concepts of job satisfaction and organizational commitment; the relationship between job satisfaction and organizational commitment; the significance of job satisfaction in the global workplace; and the significance of organizational commitment in the global workplace. Job satisfaction is important from the perspective of maintaining appropriate employees within the organization. Organizational commitment plays an essential role in determining whether employees will stay with the organization and enthusiastically work toward organizational goals. Retention of employees is one of the most significant outcomes of organizational commitment. The chapter argues that encouraging job satisfaction and organizational commitment has the potential to increase organizational performance and gain sustainable competitive advantage in the global workplace.
Phytotoxicity of Oxidised and Reduced Nitrogen Aerosols on Potato (Solanum Tuberosum L.) Crop
Authors: Bharali Bhagawan , Ullah Zafar , Haloi Bhupendra , Chutia Jayashree , Chack Sonbeer
Published: November 2016

In a field trial (2012), simulated aerosols: NH4Cl (reduced) and NaNO2 (oxidised) @ 10 & 20 kg ha-1y-1 (˜ 100 ppm & ˜ 200 ppm respectively), 1000 cm3m-2 of each along with a control were misted to population of Kufri Jyoti at different growth stages viz., vegetative (10-60 DAS), tuber initiation (60-90 DAS) and tuber bulking >90DAS). The higher dose of aerosols lowered nitrate reductase activity, nitrogen use efficiency, cell membrane stability, tuber yield, but increased photosynthesis, peroxidise activity significantly. The mechanisms of injury in terms of higher peroxidase activity and lower membrane stability of leaf cells have been elucidated. Foliar feeding of nitrogenous pollutant in the form of aerosols to plants at juvenile stage is important in addition to basal use of recommended fertilizers.
Thermo-Mechanical Training of Stainless Steels to Improve Damping Capacity
Authors: Watanabe Yoshimi , Iwata Naoya , Sato Hisashi
Published: November 2016

The effects of thermo-mechanical training on damping capacity of two types of stainless steels, Fe-18Cr-8Ni (SUS 304) and Fe-25Cr-20Ni (SUS 310S) stainless steels, are studied. The thermo-mechanical training with bending deformation is adopted, since vibration manner in internal friction measurement is bending mode. An anisotropic damping capacity as well as hardness of samples is studied. It is found that deformation induced ε-martensite is observed for trained SUS 304 sample, while deformation twins are formed in the trained SUS 310S sample. It is also found that internal friction of SUS 304 sample is larger than that of SUS 310S sample. Increase in number of training results in an increase in the internal friction and hardness. In addition, anisotropic damping capacity is observed in the samples subjected the thermo-mechanical training. To be concluded, the thermo-mechanical training is useful for enhancement of both damping capacity and strength of SUS 304 and SUS 310S stainless steels.
Effect of Layer-by-Layer Texture Inhomogeneity on the Stress Corrosion of Gas Steel Tubes
Authors: Perlovich Yuriy , Krymskaya Olga , Isaenkova Margarita , Morozov Nikolay , Ryakhovskikh Ilya , Esiev Taimuraz
Published: November 2016

Based on the data of X-ray texture and structure analysis of the material of main gas pipelines it was shown that the layerwise inhomogeneity of tubes is formed during their manufacturing. The layerwise texture inhomogeneity of steel tubes, obtained by hot rolling at the air, differs depending on variation of technological parameters of their processing in inner and outer layers, i.e. the temperature and deformation gradients, penetration of interstitial impurities into the surface layer from surrounding atmosphere etc. The thickness of the surface layer with modified texture parameters depends on the temperature of rolling and its regime. Under exploitation when stress-corrosion cracks grows and reach the layer with a modified texture, their opening is slowing down or stops because of the high mutual misorientation of grains of different layers and the necessity of changing the plane of moving cracks, what requires additional tensile stresses. Layered textures of different gas tubes were compared. It was shown that character and degree of arising inhomogeneity correlates with the tubes resistance to stress-corrosion cracking.
Resolving the Strength-Ductility Paradox through Severe Plastic Deformation of a Cast Al-7% Si Alloy
Authors: Kumar Praveen , Kawasaki Megumi , Langdon Terence G.
Published: November 2016

Ultrafine-grained (UFG) materials produced by severe plastic deformation (SPD) may show both enhanced ductility and strength and hence resolve the so-called strength-ductility paradox. To gain mechanistic insights into such resolution, the effect of high-pressure torsion (HPT) on the microstructure and mechanical behavior was studied using a cast Al-7 wt. % Si alloy. As expected, the grain size decreased while the fraction of high-angle grain boundaries and microhardness increased due to HPT processing. However, tensile testing at room temperature revealed a simultaneous increase in strength and ductility compared to the as-cast sample. The samples showing simultaneous increase in strength and ductility also showed an increased contribution from grain boundary sliding (GBS), even at room temperature, which is attributed to the existence of a high fraction of high-angle and high-energy grain boundaries. It is proposed that the occurrence of moderate GBS, providing ductility, in very small size grains provides Hall-Petch strengthening and this suggests a potential combination for simultaneously achieving high strength and high ductility in SPD-processed UFG materials.
Separating Technology of Pure Zirconia from Zircon-Sand by the Ar-H2 Arc Plasma Fusion and the Microwave Leaching
Authors: Lee Jeong Han , Kang Da Som , Moon Min Kuk , Hong Sung Kil
Published: November 2016

Zirconia (ZrO2) has excellent properties such as high toughness, high strength, thermal stability and high corrosion resistance. Thus, recent zirconia has been spotlighted as a dental material. Most of pure zirconia has been separated from zircon sand (ZrSiO4) by wet refining process which is very complex and not an environmental. The arc plasma fusion method has the advantages as a sustainable process that can easily and quickly get very good fine and high pure powders from the original materials compared with traditional wet method.
In this study, zircon sand is separated into zirconia and silica by using the Ar-H2(hydrogen) arc plasma refining. And then silica is removed from it by the microwave leaching method to produce a high pure zirconia. Argon gas, hydrogen gas, copper anode and tungsten cathode are used for the plasma arc generation. To facilitate zirconia and silica separation, carbon of 1-3molar ratios are added with zircon sand. Plasma melting were sequentially conducted two processes. After a reduction process using Ar gas only, it was refined using a mixed gas of Ar-H2. After melting and water cooling in chamber, the solid phases composed with zirconia and silica were obtained at 240 ̊C, and 20% sulfuric acid solution was used as the leaching materials to obtain a high purity zirconia (more than 99%).
The Role of Preliminary Heat Treatment in the Formation of Ultrafine-Grained Structure in the Implementation of the Combined Process "Rolling - Equal Channel Angular Pressing"
Authors: Naizabekov Abdrakhman B. , Lezhnev Sergey , Panin Evgeniy , Volokitina Irina
Published: November 2016

In recent years was developed a number of new methods of processing of metals by pressure aimed at obtaining metal with sub-ultrafine-grained structure, the basic principle of which is the realization in the process of deformation of simple shear scheme. One of those ways is pressing blanks in matrices of different designs, in particular in equal-channel step die. However, this method has a significant disadvantage - it can’t be used for deforming of lengthy billets. Another disadvantage of this method of deformation is that it does not provide the continuity of the pressing process. For removing these shortcomings at the Department "Metal Forming" of Karaganda state industrial University was developed a combined process "Rolling-pressing" using equal channel step matrix with calibrated and smooth rolls. This work investigates the impact of the proposed combined process "rolling-pressing", and also preliminary and final heat treatment during the implementation of this combined process on the evolution of microstructure and mechanical properties of copper alloy. Obtained in the course of these studies, the results indicate that the proposed technology can be recommended for implementation in production to produce blanks of ferrous and non-ferrous metals and alloys with ultrafine-grained structure and high level of mechanical properties.
The Effect of Process Parameters in Interdendritic-Melt Solidification Control Technique on the Microstructure and Properties of a Ni-Base Superalloy
Authors: Zheng Liang , Zhang Guo Qing , Daisenberger Dominik , Li Zhou , Xiao Cheng Bo
Published: November 2016

A novel technique called interdendritic-melt solidified control (IMSC) was developed to manufacture equiaxed superalloy in the efforts of reducing porosity. The effect of process parameter, such as withdrawal rate, of the IMSC on the porosities and mechanical properties of IN792 alloy was investigated, compared with conventional investment casting (CC) technique. The IMSC and CC samples were characterized by optical metallography and scanning electron microscopy. In addition, the minor phases, such as MC carbides and trace amount of η phase, were identified by synchrotron X-ray diffraction. The results indicate that proper withdrawal rate for IMSC can produce castings with much reduced porosity and higher stress rupture properties at elevated temperature compared to conventional investment casting. However, fast withdrawal rate will produce much severe porosity and lower mechanical property.
Experimental Bio-ESPI for Validation of Magnetic Induced Deformation on HeLa Cells
Authors: Lietzau Kai Henning , Stollfuß Carsten , Richetta Maria , Foitzik Andreas H.
Published: November 2016

The determination of mechanical properties can provide insight into complex biochemical processes such as the cell cycle and even the progression of diseases. However, this field of biomechanical research strongly depends on a high-resolution measurement technology and a gentle stimulation method in order to examine these mostly biological samples in their original condition. In terms of this work, a different approach utilizing a modified ESPI setup and two types of ferro-fluids is presented. By exposing the prepared specimen to an electro-magnetic field it has been possible to induce a local displacement and to monitor the deformation with the adapted ESPI setup.
Morphological Evolution of Carbides in DZ125 Superalloy during Heat Treatment
Authors: Liu Li Rong , Han Shuo , Pu Yi Fan , Peng Zhi Jiang , Zhang Ming Jun
Published: November 2016

Morphological evolution of carbides in DZ125 superalloy during heat treatment was investigated by using SEM and EDS. The results show that in DZ125 directionally solidified superalloy, the MC carbide is either smooth platelet or bone-shaped structure with nodes in morphology in as-cast state, which is rich in Ta, Ti and Hf. During solid solution treatment, parts of primary MC carbides dissolve, so that the morphology of MC carbide changes from smooth and regular surface to scattered configuration. During aging heat treatment and long term aging, the secondary MC carbides enriched in Hf element precipitated from the matrix. Moreover, there is some M6C carbide enriched in W element precipitated on the grain boundary. With the process of heat treatment, the content of Hf element in MC carbides increases obviously.
Analysis of the Static Recrystallization Behavior of Nb-Ti Microalloyed Steels Including Low Strain Levels
Authors: Sanz L. , Pereda Beatriz , López B.
Published: November 2016

Semi-empirical models for predicting the austenite static recrystallization behavior are widely used in designing thermomechanical treatments to improve final mechanical properties. However, a problem with these models is that their utility can be limited to the range of deformation conditions and chemical compositions they were developed for. This work focuses on the study of the applicability of current recrystallization models to the range of low strain conditions and/or high Nb microalloying additions (≈0.1%). To do so, the recrystallization behavior of two low carbon Nb-Ti microalloyed steels (0.04 and 0.11% Nb and ≈0.01% Ti) has been investigated by torsion tests. Experimental results for recrystallization time and recrystallized grain size have been compared to previously developed equations. It has been observed that at low strains (ε = 0.1) the predictions fail. A dependence of the n Avrami exponent both on temperature and applied strain was also found.
Friction Stir Welding on Light-Weight Metal - Aluminum Alloy Al6061
Authors: Shunmugasamy Vasanth Chakravarthy , Mansoor Bilal
Published: November 2016

Friction stir welding (FSW) is a solid state joining process in which metals are joined together using frictional heat and severe plastic deformation. The heating and the mixing of the metals is performed using a hardened tool with a shoulder and pin. FSW of lightweight metal alloy Al6061 has been carried out in the present study. For welding aluminum the parameters used were a constant tool rotation speed of 1600 rpm and varying tool translation speeds of 250, 500, 750 and 1000 mm/min. The welded coupons were characterized for microstructural observations and mechanical properties such as tensile and Charpy impact properties. The tensile and impact properties were studied at two different temperature namely, room temperature (RT) and 300°C. The FS welded aluminum specimens showed 86% – 98% tensile yield strength, in comparison to the base material at RT. At 300°C, the yield strength was observed to be 85% to 93% of the base material value. For the impact properties, the Al specimens showed 60% – 140% specific impact energy, in comparison to their respective base materials. Based on the mechanical properties and microstructural examination, the optimal weld parameter was identified as 1600 rpm and 250 mm/min which is dependent on the tool pin and shoulder design utilized in the study.
Building Blocks for Artificial Extracellular Matrices Based on Cross-Linkable Polysaccharide and Glycosaminglycan Sulfates
Authors: Becher Jana , Moeller Stephanie , Schnabelrauch Matthias
Published: November 2016

Natural sulfated glycosaminoglycans (GAGs) play a crucial role as components of the extracellular matrix (ECM). They participate in the regulation of important cellular functions including cell growth, differentiation and signalling. The generation of artificial ECM mimicking selected functions of the native ECM is a promising approach to improve the biological acceptance of materials which are in direct contact to living tissue. In this context we developed synthesis routes for polysaccharide and GAG derivatives bearing both bioactive sulfate and reactive (meth) acrylate functions of different degrees of substitution within the sugar repeating unit. In addition, we studied the photochemically initiated cross-linking of these biopolymer derivatives to form biodegradable hydrogels usable as coatings for biomaterials or scaffolds in tissue engineering.
Microstructure Evolution during LCF of a 10%Cr Steel at Room Temperature
Authors: Mishnev Roman , Dudova Nadezhda , Kaibyshev Rustam
Published: November 2016

The influence of cyclic loading on microstructure and hardness of a 10%Cr steel with 3%Co and 0.008%B was examined at room temperature and total strain amplitudes of ±0.25% and ±0.6%. Low cycle fatigue (LCF) curves exhibit a stress peak after a few cycles. Hardening is attributed to an increase in dislocation density; no changes in lath size were observed. Then stress tends to decrease monotonically with number of cycles that is indicative for material softening. At εac =±0.25%, strain softening is attributed to decreasing dislocation density and lath coarsening under LCF, whereas at εac =±0.6%, the knitting reaction between dislocations comprising lath boundaries and trapped lattice dislocation leading to the transformation of lath boundaries to subboundaries is a reason for hardness decrease and strain-induced subgrain coarsening.
Microstructure of Rapidly Solidified Melt-Spun Ribbon in AlCoCrFeNi2.1 Eutectic High-Entropy Alloys
Authors: Nagase Takeshi , Takemura Mamoru , Matsumuro Mitsuaki
Published: November 2016

The microstructure of rapidly solidified melt-spun ribbon in AlCoCrFeNi2.1 eutectic high entropy alloys (EHEAs) was investigated for clarifying the effect of rapid solidification on the constituent phases and microstructure of specimens formed through solidification. XRD analysis indicates that the melt-spun ribbons were composed of a mixture of fcc and bcc phases. The rapidly solidified melt-spun ribbon shows a fine poly-crystalline structure with fcc matrix phase and crystalline precipitates in the grain boundary, indicating that the solidification structure in the melt-spun ribbon was significantly different from that obtained by conventional casting processes.
Compressive Residual Stresses and Associated Surface Modifications Induced in Ti6Al4V by Laser Shock Processing
Authors: Ocaña José Luis , González-Carrasco J.L. , Lieblich M. , Barriuso S. , Porro J.A. , Ruiz de Lara L. , Díaz M. , Santiago J.A.
Published: November 2016

Laser shock processing (LSP) is increasingly applied as an effective technology for the improvement of metallic materials’ mechanical and surface properties in different types of components, mostly as a means of enhancement of their fatigue life behavior. As reported in previous contributions by the authors, a main effect resulting from the application of the LSP technique consists in the generation of relatively deep compression residual stresses fields into metallic components allowing an improved mechanical behaviour. In this paper, the special case of Ti6Al4V alloy is considered from a more fundamental point of view, with specific consideration of the microstructural changes and residual stresses fields justifying those macroscopic effects. From a concrete point of view, the effect of the application of different typical LSP intensities on the microstructure and residual stresses fields introduced in this material and their possible correlation to the associated surface effects are analyzed.
Fundamental Aspects of Rolled Zn Alloy Sheet Formability: Structure-Property and Failure Mode Relationships
Authors: Pantazopoulos George , Toulfatzis A. , Vazdirvanidis A. , Rikos A.
Published: November 2016

In the present work, critical testing methods are employed in order to assess the formability of a Zn-Ti-Cu alloy, evaluating, therefore, the anisotropic properties of the produced sheet. The determination of plastic strain ratios and the induced combined mathematical expressions, utilizing bi-axial strain measurements for the various test directions (0, 45 and 90 degrees towards the RD), together with the performance of cupping tests are compiled, aiming to rank and interpret the bending and sheet metal roll-forming capability. Moreover, the microstructural characterization is realized to address the influence of grain and phase structure on the sheet metal formability and identify potential optimization routes. Fracture analysis approach elucidated the micro-mechanisms prevailed in damage evolution and accumulation during monotonic loading, signifying the importance of microstructure development during thermomechanical process history.
Influence of Initial Heat Treatment on the Microhardness Evolution of an Al-Mg-Sc Alloy Processed by High-Pressure Torsion
Authors: Pereira Pedro Henrique R. , Huang Yi , Langdon Terence G.
Published: November 2016

An Al-3% Mg-0.2% Sc alloy was subjected to annealing or solution treatment and further processed by HPT at room temperature. Microhardness measurements were taken along the middle-sections of the discs and they demonstrated that a very substantial hardening is achieved during HPT processing regardless of the initial heat treatment. Hardness values of ~200 Hv were recorded at the edge of the samples although the microhardness distribution remained inhomogeneous along the diameters of the discs after 20 turns of high-pressure torsion. In addition, the microhardness of the solution treated Al-Mg-Sc samples continued to increase with the equivalent strain imposed by the anvils even after 30 turns of HPT processing whereas the hardness at the edges of the annealed discs saturated after 10 turns. These differences in the hardness evolution are attributed to the higher Mg content in solid solution in the case of the solution treated samples and its influence on delaying the recovery rate of this aluminium alloy.
Modeling of Grain-Boundary Mobility and Nucleation Rate during Discontinuous Dynamic Recrystallization in Ni-Nb Alloys and a High-Purity Alloy Derived from SAE 304L
Authors: Piot David , Smagghe Guillaume , Montheillet Frank
Published: November 2016

A simple mesoscale model has been developed for discontinuous dynamic recrystallization. Each grain is considered in turn as an inclusion, embedded in a homogeneous equivalent matrix, the properties of which are obtained by averaging over all the grains. The model includes: (i) a grain-boundary migration-equation driving the evolution of grain size via the mobility of grain boundaries, which is coupled with (ii) a single-internal-variable (dislocation density) constitutive model for strain hardening and dynamic recovery, and (iii) a nucleation equation governing the total number of grains by the nucleation of new grains. All the system variables tend to asymptotic values at large strains, in agreement with the experimentally observed steady-state regime.With some assumptions, both steady-state stress and grain-size are derived in closed forms, allowing immediate identification of the mobility of grain boundaries and the rate of nucleation. An application to Ni–Nb-pure-binary model alloys and high-purity 304L stainless steel with Nb addition is presented. More specifically on one hand, from experimental steady-state stresses and grain sizes, variations of the grain boundary mobility and the nucleation rate with niobium content are addressed in order to quantify the solute-drag effect of niobium in nickel. And on the other hand, the Derby exponents were investigated varying separately the strain rate or the temperature.
Biocompatible Ceramic-Biopolymer Coatings Obtained by Electrophoretic Deposition on Electron Beam Structured Titanium Alloy Surfaces
Authors: Ramskogler C. , Cordero L. , Warchomicka Fernando Gustavo , Boccaccini A.R. , Sommitsch Christof
Published: November 2016

An area of major interest in biomedical engineering is currently the development of improved materials for medical implants. Research efforts are being focused on the investigation of surface modification methods for metallic prostheses due to the fundamental bioinert character of these materials and the possible ion release from their surfaces, which could potentially induce the interfacial loosening of devices after implantation. Electron beam (EB) structuring is a novel technique to control the surface topography in metals. Electrophoretic deposition (EPD) offers the feasibility to deposit at room temperature a variety of materials on conductive substrates from colloidal suspensions under electric fields.
In this work single layers of chitosan composite coatings containing titania nanoparticles (n-TiO2) were deposit by EPD on electron beam (EB) structured Ti6Al4V titanium alloy. Surface structures were designed following different criteria in order to develop specific topography on the Ti6Al4V substrate. n-TiO2 particles were used as a model particle in order to demonstrate the versatility of the proposed technique for achieving homogenous chitosan based coatings on structured surfaces. A linear relation between EPD time and deposition yield on different patterned Ti6Al4V surfaces was determined under constant voltage conditions, obtaining homogeneous EPD coatings which replicate the 3D structure (pattern) of the substrate surface. The present results show that a combination of both techniques can be considered a promising surface modification approach for metallic implants, which should lead to improved interaction between the implant surface and the biological environment for orthopaedic applications.
Bridging the Gap between Ab Initio and Large Scale Studies - A Monte Carlo Study of Cu Precipitation in Fe
Authors: Redermeier Alice , Kozeschnik Ernst
Published: November 2016

In the present study, we investigate the performance of efficient pair potentials in comparison to accurate ab initio potentials as energy descriptions for Monte Carlo simulations of solid-state precipitation. As test scenario, we take the phase decomposition kinetics in binary Fe1-xCux. In a first effort, we predict thermodynamic equilibrium properties of bcc-rich Cu precipitates in an Fe-rich solution with a temperature and composition dependent Cluster Expansion. For this Cluster Expansion, combined ab inito and phonon calculations for various configurations serve as input. Alternatively, we apply the Local Chemical Environment approach, where the energy is described by computationally efficient pair potentials, which are calibrated on the first principles cluster expansion results. We observe that these fundamentally different approaches provide similar information in terms of the precipitate radius, chemical composition and interface constitution, however, the computational effort for the Local Chemical environment approach is significantly lower.
Microstructure and Friction Behavior of AISI 52100 and D2 Steels Subjected to Ultrasonic Nanocrystalline Surface Modification (UNSM) Technique at a High Temperature
Authors: Amanov Auezhan , Kim Jun Hyong , Pyun Young Sik
Published: November 2016

In this study, two different AISI 52100 bearing and D2 tool steels were subjected to ultrasonic nanocrystalline surface modification (UNSM) technique at ambient and high temperature of 500 °C. The objective of this study is to characterize the microstructure and to investigate the effectiveness of UNSM technique on the friction and wear behavior of those steels. The friction and wear behavior of the specimens against AISI52100 bearing steel ball with a diameter of 10 mm was carried out using a micro-tribo tester under dry conditions. The hardness with respect to depth from the top surface was measured using a microhardness. The change in the microstructure of the specimens before and after UNSM treatment was characterized by scanning electron microscopy (SEM). The findings from this preliminary study are expected to be implemented to the bearings and tools to increase the efficiency and performance of the components.
Influence of Different pH and Fluoride Addition on the Corrosion Behavior of the Sintered CoCr Alloy Ceramill Sintron Compared to the Cast Alloy Girobond NB
Authors: Schille Christine , Schweizer Ernst , Hoffmann Rita , Noack Falko , Geis-Gerstorfer Juergen
Published: November 2016

In addition to conventionally casting, dental metallic framework can be manufactured using different CAD/CAM technologies (selective laser melting, milling). The milling of porous CoCr blanks followed by sintering under protective gas is a new 2012 introduced dental technology called Ceramill Sintron. For this new material so far, there exist few studies on the corrosion behavior. The aim of this study was to investigate the influence of different pH values as well as fluoride additions on the corrosion behavior of the sintered CoCr alloy compared to the cast condition by electrochemical corrosion measurements according to ISO 10271.
Liquid Composite Molding: A Widely Used Group of FRPC Processing Techniques, but still a Challenging Topic
Authors: Schledjewski Ralf , Grössing Harald
Published: November 2016

Liquid Composite Molding techniques are widely used technologies in order to manufacture fiber reinforced plastic composites using near-net-shaped preforms consisting of single reinforcements, e.g. woven textiles or multiaxial fabrics. All LCM process variants have in common to impregnate and saturate dry reinforcing structures with a liquid thermoset resin system. The challenge during LCM process development and mold designing is the prevention of potential error sources for safe in-spec FRPC production. Race tracking zones and air inclusions are two major issues which need to be avoided in order to ensure an excellent FRPC quality.
The knowledge about preform transmissibility, i.e. permeability, of the dry reinforcing structure to the liquid flow during the saturation phase is of major importance. The knowledge about the filling and flow behavior during FRPC processing is responsible for the process efficiency and process success. In-plane and out-of-plane permeability characterization is of great interest. Especially industry is interested in precise permeability values for numerical mold filling simulations in order to support the process development and the mold design. Industrial work is also carried out for filling strategies and textile development as well as textile improvement.
The paper presents different LCM processing techniques and discusses the advantages and disadvantages as well as the linked challenges during FRPC processing. Furthermore, the in-plane permeability characterization of reinforcing structures and moreover influencing factors on the filling behavior are presented. Finally the significance of accurate and reliable permeability values according to numerical filling simulations and their validity are discussed.
The Effects of Interfacial Heat Transfer Coefficient on the Microstructure of High-Pressure Die-Cast Magnesium Alloy AM60B
Authors: Sharifi Pouya , Sadayappan Kumar , Wood Jeffrey T.
Published: November 2016

This paper describes the details of a quantitative experimental and numerical study on the influence of solidification conditions, including the apparent interfacial heat transfer coefficient (IHTC) between the die and solidifying metal, on the resulting local microstructure. Multiple runs of the commercial casting simulation package, ProCASTTM, are used to model the mold filling and solidification events employing a range of IHTC values. The simulation results are used to estimate the centreline cooling curve at various locations through the casting. The centreline cooling curve, together with the die temperature and the thermodynamic properties of the alloy are then used as inputs to compute the solution to the Stefan problem of a moving phase boundary, thereby providing the through-thickness cooling curves at each chosen location of the casting. Finally, the local cooling rate is used to calculate the resulting grain size and skin thickness via previously established relationships. A comparison of the predicted and experimentally determined grain size profiles enables the determination of the apparent IHTC, which, in this study, was approximately 12000 W/m2·K.
Additional useful observations from the numerical study suggest that the IHTC has a significant influence on the skin thickness and grain size in both the skin and core regions of the casting, while the effect of die temperature is limited to influencing the skin grain size only.
Hot Torsion Tests - A Reliable Rolling Simulation Method for C-Mn Steels
Authors: Siciliano Fulvio , Allen Brian J. , Ferguson David
Published: November 2016

Torsion tests have been proven to be a successful method to simulate the hot rolling of steels. Simulation work performed at a laboratory scale together with the analysis of the resulting mean-flow-stress behavior, leads to important metallurgical information to be considered during full-scale rolling processes. In this work, two different hot deformation schedules of C-Mn steels have been performed on a Gleeble simulation system in hot torsion mode. In addition to the torsion tests, the mean-flow-stresses of industrial rolling data were analyzed. Industrial hot deformation schedules simulated using hot torsion and the mean-flow-stress values were plotted versus the inverse of absolute temperature in the same graph. All points match the same behavior showing that torsion testing is a reliable hot working simulation method.
Measurement of Residual Stresses in Linear Friction Welded In-Service Inconel 718 Superalloy
Authors: Smith M. , Bichler L. , Sediako D.
Published: November 2016

Measurement of residual strains by neutron diffraction of linear friction welded Inconel® 718 (IN 718) superalloy acquired from a mid-service aero-engine disk was undertaken in this study. Residual strain and stress throughout the various weld regions including the heat affected zone (HAZ), thermomechanical affected zone (TMAZ) and dynamically recrystallized zone (DRX) were characterized. The residual stresses were observed to increase from the base material to the weld interface, with a peak stress at the weld interface in all orthogonal directions. The trends for residual stress across the weld are in agreement with other work published in literature for solid state welding of aerospace alloys, where high residual stresses were commonly reported at the weld interface.
Evaluation of the Hardening Capacity of Low-Alloyed Steels Quenched by HPGQ in Vacuum Furnaces
Authors: Liščić Božidar , Smoljan B.
Published: November 2016

The technology of High Pressure Gas Quenching (HPGQ) in modern vacuum furnaces has already reached the level of 20 to 25 bar pressure and up to 80 m/s gas flow velocity. By using primarily nitrogen (N2) it is possible to quench also low-alloyed steels, and to compete, in some cases successfully, with oil quenching. This depends basically on the hardenability of the steel and on the cross-section thickness of the quenched workpiece. The present work explains experimental testing of steels' hardenability when gas quenching is applied. For determination and vizualization of the hardening capacity of steels quenched by HPGQ, a computer aided method has been developed for axially symmetric workpieces of any complex shape, to show at a glance the complete hardness distribution on longitudinal section. An included database of relevant steel grades and possible gas quenching parameters enables to choose another steel grade and/or other quenching parameters, and see on the display another relevant hardness distribution, without performing additional experiments.
Mathematical Model of Microstructural Evolution of Hot Rolled Wire Rods for Nb Microalloyed Steels
Authors: Oliveira Felipe , Lino Roney , Barbosa Ronaldo
Published: November 2016

Wire rods are supplied for end users manufactures of products with increasing complexity and mechanical properties requirements. Demanding end users field applications must provide high yield stress, ductility and, in certain cases, toughness. These properties can be improved simultaneously if appropriate rolling technique and alloy design are used. It has been known for decades in the flat rolling industry that microalloyed steels can be produced achieving requirements just mentioned. The technology, however, is less often seen applied at the long products industry.
In order to obtain metallurgical sound products, steelmakers need to run industry scale trials. These, however, are costly, time consuming and results are not always easy to analyze given the number of variables involved. Mathematical models are frequently used in order to reduce plant trials reducing costs. There models already published in the literature suitable for wire rod applications. They are however more concerned with the thermomechanical process than with alloy design. This paper presents a model for wire rod rolling of microalloyed steels in which some consideration to alloy design is taken into account. Predicted and mill trial results were compared. Reasonable agreement was found proving the model to be a valuable tool in both schedule and alloy design.
Microstructure Refinement in the CoCrFeNiMn High Entropy Alloy under Plastic Straining
Authors: Stepanov Nikita , Shaysultanov Dmitry , Yurchenko Nikita , Klimova Margarita , Zherebtsov Sergey , Salishchev Gennady
Published: November 2016

The effect of plastic deformation under various conditions of the equiatomic CoCrFeNiMn alloy with single face-centered cubic phase structure was studied. The alloy was rolled at room and cryogenic temperatures, and uniaxially compressed at room temperature and temperatures of 600-1100°C with different height reductions. In addition, multiaxial forging at 900-1000°C was performed. Scanning and transmission electron microscopy, including EBSD analysis, was widely employed to characterize microstructure of the deformed alloy. At room and cryogenic temperatures, mechanical twinning and shear banding plays play dominant role in microstructure evolution. Extensive refinement of the microstructure occurs as the result of rolling with reduction of 80%. During deformation at 600-1100°C, discontinuous dynamic recrystallization takes place. The recrystallized grains size and their volume fraction increases with increase of deformation temperature. Multiaxial forging at 900-1000°C was used to produce fully recrystallized structure with average grain size of 6.7 μm. The alloy in the initial condition had low yield strength of 160 Mpa but remarkable tensile ductility of 68%. Rolling substantial increases yield strength to 1120-1290 MPa, but results in loss of ductility. After multiaxial forging the alloy has balanced combination of properties – yield strength of 280 MPa and elongation of 56%.
Novel ESPI Measurement Prototype for Analyzing Biological Samples from Cell Culture Technique
Authors: Stollfuß Carsten , Lietzau Kai Henning , Richetta Maria , Foitzik Andreas H.
Published: November 2016

An essential part of cell cultivation via cell culture technology is the determination and monitoring of culture parameters. Such parameters refer to the vitality or mutual mutations of the cell culture, while the actual number of living cells in each batch indicates the correct growth rate rather than stagnation or an overgrowth of the cell culture. Today such parameters are determined by applying light microscopy methods or by staining specific constituents of the cells. Commonly such methods are a stressful procedure for the studied cells. Most applied dyes are toxic over a certain period of time and thus they are used in low concentrations only when necessary. Within this work a new kind of measurement device prototype was designed to address these problems. This device is based on the Electronic Speckle Pattern Interferometry (ESPI). ESPI is an optical high-resolution method combined with a photonic analysis system capable of analyzing cellular deformations and oscillations. In this approach the combination of a greatly modified microscope together with ESPI method is presented. The apparatus allows the determination of cellular deformation (i) at very high magnifications, (ii) with high lateral resolution. Furthermore the system studies (iii) contact free, (iv) in vitro cells, in a non-invasive and non-destructive way. A co-developed cultivation system allows monitoring the culture parameters in real time minimizing the stress for the cell culture. Since no additional substances are needed, the presented prototype is automated to a large extent and can be operated by a special control-and regulation system (CRS) based on a microcontroller development board (Arduino Mega).