bluuebunny/crossref_metadata_2025 huggingface dataset:
Deprescribing to Reduce Medication Use: Will This Help Your Patient?
Authors: Howland Robert H.
Published: November 2016

Polypharmacotherapy is a commonly used, but frequently criticized, clinical practice. Deprescribing is the process of discontinuing inappropriate or unnecessary medications, with the goals of decreasing adverse events and drug–drug interactions, simplifying medication regimens to enhance adherence, and reducing costs associated with medication use while maintaining or improving clinical outcomes. Studies of groups of patients suggest that deprescribing medication is feasible and safe, but individual experiences are masked by group data. Although deprescribing can decrease medication exposure, evidence of the effectiveness of deprescribing medication on improving clinical outcomes is conflicting or lacking. Medication necessity or appropriateness should be assessed on a case-by-case basis and from visit to subsequent visit over time. Deprescribing medication should be accompanied by vigilant monitoring for adverse drug withdrawal effects or relapse of an underlying condition. [
Journal of Psychosocial Nursing and Mental Health Services
,
54
(11), 21–24.]
Metabolic Syndrome: Psychiatric–Mental Health Nurses' Knowledge of Risks and Care Practices
Authors: Bolton Paula S. , Knight Margaret , Kopeski Lynne M.
Published: November 2016

Comorbidity of serious mental illness (SMI) and metabolic syndrome contributes to the reduced lifespan of individuals with SMI. Integration of physical and mental health care has been slow. The current study explored the level of knowledge of metabolic syndrome and practices of psychiatric–mental health nurses related to metabolic syndrome risks. Using a knowledge survey and adapted Mental Health Nurse Physical Health Attitude Scale, the researchers surveyed 175 psychiatric nurses through an online social media website. Of respondents, 52% identified all five risk factors for metabolic syndrome. However, only 70.8% knew all recommended physiological monitoring markers. There was no significant relationship between knowledge score and integration of physical health care activities in practice; however, knowledge regarding metabolic syndrome risk factors was high. Currently, integration of this knowledge into care is lagging. Nurse educators must integrate assessment, planning, intervention, and evaluation of physical health status and related needs of individuals with SMI. [
Journal of Psychosocial Nursing and Mental Health Services, 54
(11), 44–53.]
Characterization of gypsum plasterboard with polyurethane foam waste reinforced with polypropylene fibers
Authors: Alameda L. , Calderón V. , Junco C. , Rodríguez A. , Gadea J. , Gutiérrez-González S.
Published: November 2016

Gypsum plasterboard that incorporates various combinations of polyurethane foam waste and polypropylene fibers in its matrix is studied. The prefabricated material was characterized in a series of standardized tests: bulk density, maximum breaking load under flexion stress, total water absorption, surface hardness, thermal properties, and reaction to fire performance. Polypropylene fibers were added to the polyurethane gypsum composites to improve the mechanical behavior of the plasterboard under loading. The results indicate that increased quantities of polymer waste led to significant reductions in the weight/surface ratio, the mechanical strength and the surface hardness of the gypsum, as well as improving its thermal resistance. The polypropylene fibers showed good adhesion to the polymer and the gypsum matrix, which enhanced the mechanical performance and the absorption capacity of these compounds. The non-combustibility test demonstrated the potential of the new material for use in internal linings.
Reconstruire les paysages urbains et ruraux d’Alsace après 1945
Authors: Bolle Gauthier
Published: November 2016

Certains aspects de la seconde reconstruction demeurent encore peu traités par les historiens, notamment les liens et continuités entre opérations urbaines et rurales, par-delà les registres stylistiques divers. En rapprochant des projets de logements reconstruits et réalisés en Alsace au début des années 1950, on décèle de nombreuses variations entre persistance du langage traditionnel et revendication plus nette d’un vocabulaire moderne. Ainsi, plusieurs thématiques fortes émergent de cette analyse. En premier lieu, la volonté des architectes alsaciens de ressusciter des paysages ruraux et urbains disparus, réinterprétant des traditions architecturales locales. Puis, l’apparition et le développement de nouvelles formes d’urbanisation plus ou moins négociées avec la ville existante. C’est enfin et surtout le logement devenant un espace mieux orienté, à la fois compact et fonctionnel, qui semble être le vecteur d’unité de l’ensemble des réalisations ici considérées. L’histoire de ces réalisations, brosse aussi le portrait d’une scène professionnelle et des divers acteurs qui se mettent au service de processus de modernisation qui vont s’intensifier fortement dans la décennie suivante.
La narration au service de la politique monétaire : étude comparée du premier discours à Mansion House de deux gouverneurs de la Banque d’Angleterre
Authors: Harris Laurence
Published: November 2016

Cette étude propose d’explorer les frontières narratives en anglais de l’économie et de la finance à partir de deux discours de gouverneurs de la Banque d’Angleterre extraits d’un corpus de soixante-et-onze allocutions prononcées depuis la nationalisation de la Banque en 1946. L’étude se présente en trois parties. La première partie aborde le cadre théorique et méthodologique de l’étude. La deuxième partie mène une lecture comparée des deux discours du corpus intégrant les structures narratives les plus abouties et s’interroge sur la visée de ces macro-récits. La troisième partie examine la signification des micro-récits enchâssés dans la trame discursive et les enjeux qu’ils soulèvent. L’objectif est de mettre au jour les ressorts narratifs auxquels les gouvernements ont recours afin de capter l’attention et d’obtenir l’adhésion de plusieurs publics, tout en parvenant à inspirer confiance, à rassurer et à guider face à de multiples incertitudes.
Medical Humanities in the English classroom: building students’ professional identity through poetry
Authors: Marthouret Thibault
Published: November 2016

Les Humanités médicales et la médecine narrative permettent aux professionnels de santé d’acquérir une meilleure compréhension de leurs patients et de leurs collaborateurs tout en étayant le développement de leur identité professionnelle et en cultivant chez eux les compétences relatives à l’observation, à l’analyse et à l’autoréflexion. La lecture détaillée de poèmes afin d’affiner les capacités d’interprétation est une pratique courante dans les cours de médecine narrative, tout comme le recours aux activités d’écriture poétique pour promouvoir la créativité, la connaissance de soi et l’empathie. Cet article présente un module expérimental d’anglais ayant pour but d’initier des étudiants de médecine à l’Université de Bordeaux au champ des Humanités médicales et de les sensibiliser à leur culture de spécialité ainsi qu’aux réalités phonologiques et prosodiques par l’intermédiaire de poèmes traitant de sujets médicaux. Il propose une réflexion sur la place de la poésie dans le cours d’anglais médical et le recours à l’écriture créative comme outil permettant aux étudiants d’explorer et de rapporter certaines expériences de leur champ disciplinaire ainsi que de consolider leurs compétences langagières.
Devenir styliste. Des trajectoires genrées dans les écoles de mode
Authors: Divert Nicolas
Published: November 2016

Depuis les années 1960, le secteur de l’habillement, désigné communément comme la mode, focalise son attention sur les activités à forte valeur ajoutée. Parmi elles, la création symbolise son dynamisme et le styliste en est sa figure. Incarnée régulièrement par des hommes dans un secteur d’activités identifié comme féminin, une division sexuelle du travail traditionnelle se donne à voir. A partir d’une enquête ethnographique dans deux écoles supérieures de mode situées à Paris, cet article se propose d’étudier la manière dont les trajectoires des garçons et des filles se construisent et se différencient au cours de leurs études. Peu nombreux en formation, les garçons sont recherchés et le « stigmate » lié à leur orientation atypique devient une source de distinction. L’enquête montre cependant que ces trajectoires masculines génèrent des interrogations relatives à leur sexualité de sorte que sexe, genre et sexualité doivent être appréhendés conjointement.
Les formations supérieures françaises délocalisées à l’étranger : Expériences migratoires d’étudiants français au Vietnam
Authors: Cerbelle Sophie
Published: November 2016

Les étudiants français sont de plus en plus nombreux à poursuivre leurs études à l’international. Parallèlement à ces migrations estudiantines se développent des projets d’exportation de l’enseignement supérieur français à l’étranger. Peu de recherches portent aujourd’hui sur les étudiants français qui poursuivent leurs études dans des formations françaises délocalisées et dans des zones géographiques moins classiques. C’est tout l’objet de ce travail qui cherche à comprendre les processus d’intégration sociale et scolaire de jeunes français inscrits dans des formations universitaires françaises délocalisées au Vietnam et offre l’opportunité de questionner l’offre de formation française à l’international.
L’éthique du care dans le champ éducatif ou le nouveau paradigme de la bienveillance
Authors: Roux-Lafay Corinne
Published: November 2016

L’éthique du care, fondée sur l’attention portée à la singularité du sujet en sa vulnérabilité constitutive, est au cœur de l’École de la refondation et interroge à la fois la posture de l’enseignant et le statut de l’élève. La posture morale de l’enseignant est en effet celle d’une exemplarité sans interférence émotionnelle qui doit pourtant se conjuguer avec une bienveillance qui a pour nom sollicitude. Du côté de l’élève et en lien avec les nouveaux programmes, il s’agira de développer les compétences relationnelles relevant du care, de manière à en reconnaître l’enjeu quant à la formation du sujet. Mais ce nouveau paradigme, en ce qu’il reconfigure l’École de la République construite historiquement sur un socle de rationalité refoulant l’altérité, reste à interroger d’un point de vue critique.
State-Level Cyberbullying Policy
Authors: McNeal Ramona Sue , Kunkle Susan M. , Bryan Lisa Dotterweich
Published: November 2016

Cyberbullying is the use of information technology to deliberately hurt, taunt, threaten or intimidate someone. Currently, there are no federal statutes in the United States which directly address this problem. The response of the states has varied from attempting to use existing anti-bullying laws to limit cyberbullying to passing new laws that specifically target cyberbullying behavior. An important question is, “why are some states taking a lead in combating this cybercrime through new laws while others are relying on existing laws?” The literature on policy adoption suggests politics, resources and public need are important factors in predicting why certain states are more likely to enact government policies. This chapter analyzes the impact of these factors and others on policy adoption by exploring the level of legislative action to update existing cyberbullying laws for 2009 through 2014.
Understanding Bystanders' Willingness to Intervene in Traditional and Cyberbullying Scenarios
Authors: Walker Justine A. , Jeske Debora
Published: November 2016

Bullying incidents in traditional and online settings are a cause for concern to many parties. The goal of the current study was to explore the extent to which a bystander would intervene in a bullying incident and the degree to which this behavior is influenced by group size (the number of other witnesses), the setting (traditional or cyberbullying), and gender of the victim. Using an online survey method, participants were presented with eight bullying scenarios, each of which involved verbal bullying of a victim. Participants (N = 82) were asked to report how likely they would be to intervene in each of these scenarios. Results showed that female victims were more likely to be helped than male victims. Furthermore, female participants were more willing to intervene than the male participants in the cyberbullying scenarios. Altruism was a positive predictor of participants' willingness to intervene. The present findings suggest that certain gender differences in helping behavior may depend on the context in which bullying is observed (traditional or cyberbullying).
Comparing Peer-to-Peer and Individual Learning
Authors: Kelly Patrick , Katz Larry
Published: November 2016

Peer-to-peer (P2P) learning within two distinct groups of disadvantaged adults was studied during a two-hour computer skills workshop. Of interest was whether or not P2P learning with this population was a viable method for increasing performance and confidence. Two qualified instructors at two locations taught the same introductory word-processing workshop to students enrolled in one of three learning intervention groups: P2P, Individual (IND), and No Intervention (NINT). Data was collected through pre- and posttests (all groups), quizzes (P2P and IND groups) and qualitative analysis of P2P group discussions. Quiz results indicated that those in the P2P group gained a better understanding of concepts than participants in the IND group; however, posttest results showed that the understanding was not maintained over time. Confidence in computer skills knowledge increased between the pre and posttest in all treatment groups, regardless of correct or incorrect answers. Analysis of P2P discussions found a significant relationship between the quality of peer discussions and the posttest scores. This study concluded there is a potential benefit of using P2P strategies with disadvantaged adults in the classroom, as confidence is developed and maintained, even as knowledge was not.
Supporting Doctoral Students through the Personalisation of a Graduate Virtual Research Environment
Authors: Costello Robert
Published: November 2016

This paper offers a case study in which a traditional Learning Management System (LMS) was enhanced through learning theories and web-based technologies to support the development of doctoral students. The model being used here, can address and support a personalised learning approach to assist postgraduate students, as part of matching their skills with a repository of rich media and activities. The mixed method research approach adopted here aided into the investigation into the Graduate Virtual Research Environment (GVRE) while analysing factors like usability, accessibility, goal orientation and evolving the learners' needs. The author argues by tailoring the gap between learning theories and technology with the complexities of human nature one can adapt the educational setting to provide a LMS which can be personalized for doctoral students.
A TPM-based Secure Multi-Cloud Storage Architecture grounded on Erasure Codes
Authors: Mugisha Emmy , Zhang Gongxuan , El Abidine Maouadj Zine , Eugene Mutangana
Published: November 2016

In cloud storage systems, data security management is becoming a serious matter. Big data and accessibility power is increasingly high, though the benefits are clear, such a service is also relinquishing users' physical possession of their outsourced data, which inevitably poses new security risks toward the correctness of the data in cloud. As a result, cloud storage security has become one of the driving components in Cloud Computing regarding to data manipulation trust on both hosting center and on-transit. This paper proposes a TPM-Based Security over Multi-Cloud Storage Architecture (MCSA) grounded on Erasure Codes to apply root of trust based on hardware authenticity. An erasure codes such as Reed-Solomon, is capable of assuring stability in storage costs with best practice to guarantee data accessibility failure recovery. A Multi-Cloud Control Node manages other Control Nodes evolved in the cloud; this work introduces TPM-Based Security functions per Control node in the architecture. This concept will resolve a number of storage security issues, hence Cloud Computing adoption.
The Onset of the Austenite to Bainite Phase Transformation for Different Cooling Paths and Steel Compositions
Authors: Pohjonen Aarne , Somani Mahesh , Pyykkönen Juha , Paananen Joni , Porter David
Published: November 2016

We present calculations of austenite to bainite phase transformation start for different cooling paths and for different steel compositions and a method to estimate the cooling water required to cool a steel strip to desired temperatures during water cooling line after industrial hot rolling. We also quantitatively compare how different alloying elements affect the phase transformation activation energy and the time required for the transformation to start and proceed to the extent that it can be detected with dilatometer. This analysis can be used for aid when designing suitable cooling paths for hot rolled steel products. The calculations of the activation energy can be used as input in more detailed microstructure models.
Improvement of Fatigue Strength of Hole Edge of Ultra-High Strength Steel Sheet by Punching Process Including Thickening
Authors: Abe Yohei , Mori Ken-Ichiro , Kosaka Ryota
Published: November 2016

The effect of the hole edge shape formed by a punching process including thickening on the fatigue strength of the hole of ultra-high strength steel sheets was investigated. The bending and tensile fatigue tests of the thickened hole edge were performed. For the bending fatigue strength, the high height of hole edge was effective because of high bending stiffness. Although the high tensile stiffness was important for the high tensile fatigue strength, the shape of hole edge was alternative. To increase both the bending and tensile fatigue strengths, a compressive process in rollover of hole edge was added for the thickened sheet having a high bending fatigue strength. It was found that the thickened and compressed hole edge of ultra-high strength steel sheet was effective in improving both the bending and tensile fatigue strengths.
Computer Simulation of the Combined Process "Helical Rolling-Pressing"
Authors: Naizabekov Abdrakhman , Lezhnev Sergey , Arbuz Alexandr , Panin Evgeniy
Published: November 2016

In this work a simulation of the innovation process "helical rolling – pressing" in the software package Simufact.Formingwas performed. The result is several models of this process. To analyze the feasibility of the process various key parameters that have a significant impact on the implementation processwere carried out. As a result, the optimal values of friction coefficients in the rolls and in the matrix, the angle of intersection of channels in the matrix and the distance of matrix from the deformation zone of the rollswere obtained.
Influence of Material and Tribological Modelling on the Prediction of Big Size Automotive Components Springback
Authors: Gil Imanol , Mugarra Endika , Agirre Julen , Mendiguren Joseba , Sáenz de Argandoña Eneko , Galdos Lander
Published: November 2016

The finite element simulation has become an essential tool for the proper design of big size automotive components stamping tooling and their process optimization. Although big improvements have been made in the last years in terms of material and tribological modelling, the accuracy of the current models should be further improved to estimate the final post-forming springback of these components, in both AHSS and mild steels.In the present paper the forming of a B-Pillar reinforcement is numerically analyzed using a DX54D mild steel and a TRIP800 high strength steel. In the first part, the influence of the elastic behavior including variable young modulus, the yield criteria and the hardening law on the final springback is studied for both materials. Secondly, the friction coefficient is defined constant and pressure dependent and springback variation is analyzed in function of this variable.In order to stablish the material and friction variables and their typical deviation, results obtained from material characterization and strip drawing tests are used.
Prediction of Forming Limit Diagram for AA5754 Using Artificial Neural Network Modelling
Authors: Mohamed Mohamed , Elatriby Sherif , Shi Zhusheng , Lin Jian Guo
Published: November 2016

Warm stamping techniques have been employed to solve the formability problem in forming aluminium alloy panels. The formability of sheet metal is a crucial measure of its ability for forming complex-shaped panel components and is often evaluated by forming limit diagram (FLD). Although the forming limit is a simple tool to predict the formability of material, determining FLD experimentally at warm/hot forming condition is quite difficult. This paper presents the artificial neural network (ANN) modelling of the process based on experimental results (different temperature, 20°C-300°C and different forming rates, 5-300 mm.s-1) is introduced to predict FLDs. It is shown that the ANN can predict the FLDs at extreme conditions, which are out of the defined boundaries for training the ANN. According to comparisons, there is a good agreement between experimental and neural network results
Production Technology for Precision Seamless Steel Tubes from the Perspective of Microhardness Changes
Authors: Mojžiš Milan , Ridzoň Martin , Bella Peter , Martinkovič Maroš , Parilák Ľudovít
Published: November 2016

The production of precision seamless steel tubes in Železiarne Podbrezová is using hot rolled tubes with multiple cold drawing passes and intermediate annealing. It utilizes intensive plastic deformation during cold drawing, taking full advantage of the microstructural state from a physical point of view. In this paper, optimization of technological processes for cold drawn tubes made from ferritic-pearlitic steel has been elaborated. We use microstructural and substructural analysis, dislocation hardening theory and stress analysis. The subject of this article is the experiment with multiple drawing passes and intermediate annealing for production of precision steel tubes with dimensions of 31.8 x 2.6 mm. The drawing itself consists of 5 processes (also called „runs“) with 7 drawing passes in total. The results presented show strain hardening of the material after drawing along with relaxation mechanism during intermediate annealing. The possibility of utilizing the microhardness values on intensity assessment of these processes is investigated, too.
T-Shape Connector Hydroforming Process Analysis
Authors: Paćko Marek , Krawczyk Janusz , Bała Piotr , Paćko Paweł , Śleboda Tomasz , Muszka Krzysztof , Hojny Marcin , Wojtaszek Marek , Cios Grzegorz , Burdzy Józef , Wydra Roman
Published: November 2016

The work is focused on hydroforming of T-shape connector for high temperature applications. A seamless part for use in industrial applications was formed in a high pressure liquid extrusion process. Due to the occurrence of faults in the final products, numerical simulations were conducted to reveal the possible sources of such failures. The numerical simulation took into account precisely determined boundary conditions allowing proper selection of processing parameters. The microstructure of charge material as well as that of the final product was also examined. Numerical simulations of the investigated extrusion process showed the possibility of obtaining good quality product, however, the quality of final part is strongly influenced by properly designed heat treatment schedule.
Effects of Ti Powder Additions in Melt-SHS Process on the Performance of Al-Ti-B Grain Refiner Alloys
Authors: Li He , Chai Li Hua , Xiang Zhi Lei , Cui Yong Shuang , Chen Zi Yong
Published: November 2016

Melt-SHS (Self-propagating High-temperature Synthesis) was used for the preparation of Al–5Ti–1B master alloy. The quality ratio of Ti powder/TiO2 in initial powder mixture was varied from 0:1 to 1:0. The AES, XRD and SEM were applied to evaluate the microstructure and phase componet. The results showed that the Al-5Ti-1B master alloy could be successful produced by the reaction of Al powder, TiO2 and H3BO3 in Al melt, while the reaction rate was slow. The microstructure mainly presents the TiAl3 particles with long strip shape. A significant improvement was noted both in reaction rate and in the grain refining efficiency when Ti powder was added to the reactants and the optimized ratio of Ti powder/TiO2 was 2:3. The TiAl3 particles were reduced and the grain refining efficiency turned bad when Ti powder was totally used to supply Ti
Effect of Direct Chill Casting Speed and Heat Treatment on Microstructure and Mechanical Properties of Al-13.9%Mg2Si Composite
Authors: Wang Dong Tao , Zhang Hai Tao , Qin Ke , Han Xing , Shao Bo , Zuo Ke Sheng , Cui Jian Zhong
Published: November 2016

The aim of this work is to investigate the effect of different casting speed in DC casting process and solution heat treatment of in situ Al-13.9%Mg2Si composite. The increasing of DC casting speed not only makes primary Mg2Si distribute more uniform and restricts segregation of primary Mg2Si particles, but also it reduces primary Mg2Si particle size. The DC casting speed significantly alter the eutectic Mg2Si phase from fibrous to fine dot-like and eutectic phase refines effectively. The results obtained from mechanical testing demonstrated that the increasing of DC casting speed intensifies both hardness and tensile strength values. Then, the billet were subjected to solutionizing at 500oC for holding time of 4h followed by quenching. The results indicate that the morphology of both primary and eutectic Mg2Si changes after heat treatment. Solutionizing leads to the dissolution of the Mg2Si particles and changes morphology from sharp edges to round shape. After solution heat treatment, tensile strength and elongation increase to 238.8MPa and 13.5%.
Effects of Mn and Cr Additions on the Recrystallization Behavior of Al-Mg-Si-Cu Alloys
Authors: Zhang Gong Wang , Nagaumi Hiromi , Han Yi , Xu Yi , Parish Chad M. , Zhai Tong Guang
Published: November 2016

Upsetting tests on two newly developed Mn and Cr-containing Al-Mg-Si-Cu alloys with various Mn contents were carried out at a speed of 15 mm/s under upsetting temperature of 450 °C after casting and subsequent homogenization heat treatment using a 300-Tone hydraulic press. STEM experiments revealed that Mn and Cr-containing α-Al (MnCrFe)Si dispersoids formed during homogenization showed a strong pinning effect on dislocations and grain boundaries, which could effectively inhibit recovery and recrystallization during hot deformation in the two alloys. Recrystallization fractions after solution heat treatment following hot deformation were measured by EBSD technique. It was found that the recrystallization fractions of the two alloys were less than 30%, giving rise to lower recrystallization fraction in the alloy with higher amount of Mn, which had higher number density of dispersoids. This implied that the finely distributed α-dispersoids were rather stable against coarsening and they stabilized the microstructure by inhibiting dislocation recovery and recrystallization during elevated temperature exposure. Increasing the content of Mn could increase the number density as well as the aspect ratio of the dispersoids, and more significantly, the effect of retardation on recrystallization were further enhanced.
The Influence of Extended and Variable Pre-Stretching on the Strength of AA2195 Alloy Taper-Rolled Plates
Authors: Rodgers B.I. , Cinderey R.J. , Prangnell Philip B.
Published: November 2016

The influence of larger pre-strains, than are currently used in industry, has been investigated on the ageing behaviour of the Al-Cu-Li alloy 2195 - in the context of producing near-net-shape, taper-rolled, thickness-tailored, plates for aerospace applications. FE modelling and simulations have demonstrated it is viable to stretch plates with rolled tapers of up to 1:1.6 in thickness. Increasing the pre-strain level at the thin end of the plate, up to 15%, resulted in a continued increase in microstructure refinement and yield strength, which rose to ~ 670 MPa without an unacceptable loss of ductility. It is shown that, even with such high pre-strains, a relatively low level of recovery occurs after artificial ageing and increasing the pre-strain is predicted to result in a reduction in strengthening from the T1 phase, due to precipitate refinement, in favour of a higher contribution from strain hardening.
Effect of Compound Modification and Cooling Rate on Microstructure and Mechanical Properties of Al-25%Si Alloy
Authors: Zhang Hai Tao , Wang Dong Tao , Qin Ke , Han Xing , Shao Bo , Zuo Ke Sheng , Cui Jian Zhong
Published: November 2016

The effect of phosphorus on primary silicon, phosphorus and mischmetal (Ce-50La) modification on primary and eutectic silicon and cooling rate on microstructure of Al-25%Si are investigated. The results show that, with the addition of phosphorus, the size of primary silicon decreases from 93.6μm to 24.75μm. The morphology of primary silicon changes from irregular to polygonal. When Al-25%Si is modified by phosphorus and mischmetal, primary and eutectic silicon all change effectively. Addition of mischmetal on the basis of phosphorus modification have no influence to primary silicon, but it can make morphology of eutectic silicon change from lamellar to short rod-like when the content of mischmetal reaches 0.5%. The cooling rate curves show the change of temperature in different height of wedge-shaped mould. When cooling rate increases, microstructure of Al-25%Si refines, the size of primary silicon decrease to 22.7μm. The results obtained from mechanical testing demonstrate that the addition of mischmetal and increasing of cooling rate increase hardness value of Al-25%Si alloy.
Phase Composition, Texture and Mechanical Properties of 80 mm Plates of Al-2.8Cu-1.7Li-0.5Mg-0.5Zn-0.1Zr-0.06Sc Alloy
Authors: Betsofen Sergey , Antipov Vladislav , Knyazev Maxim , Dolgova Margarita
Published: November 2016

Phase composition, texture and mechanical properties of plates 80 mm thick from Al-2.8Cu-1.7Li-0.5Mg-0.5Zn-0.1Zr-0.06Sc alloy were investigated. It has been found that strength characteristics are maximum in median section (ultimate strength and the yield stress of 570 MPa and 540 MPa, respectively). In 0,25T section (where T is the plate thickness) these quantities make 530 MPa and 490 MPa, and in the short transverse direction of only 490 MPa and 440 MPa. Textural studies showed that on medium layer of a plate 0,3-0,35T thick is observed identical to a matrix and δ'-phase intensive single-component texture with an arrangement of the plane {011} parallel to the plate plane with domination of a "brass" texture component {110} <112>.
Effects of Homogenization Conditions on the Microstructures of Twin-Roll Cast Foil Stock of AA8021 Aluminum Alloy
Authors: Chen Wei , Zhao Pi Zhi , Zhou Yu Li , Pan Yan Feng
Published: November 2016

AA8021 aluminum alloy twin-roll cast strips with 7mm gauge were rolled to 3.8mm gauge sheets and given homogenization, further rolled into 0.55mm gauge foil stocks with intermediate annealing. This paper investigated the influence of homogenization conditions on microstructures of foil stocks in detail. The results show that, for the foil stock made from the sheet without homogenization, the grain structure is partially recrystallized. While the grain structure of foil stock made from the sheet with medium temperature homogenization is fully recrystallized, but it is coarse near sheet surface. However, foil stock made from the sheet with high temperature homogenization has fine and uniform recrystallized grain structures. The differences of grain structures among these three kinds of foil stocks can be understood by the variation in solid solution content of Fe, Si, Mn and distribution of intermetallic compounds. The optimized homogenization condition was adopted by our plant to produce foil stock, and its grain structure was fine and uniform. The surface quality of final aluminum foil rolled from the foil stock could meet high grade requirements of customers.
Thermodynamics Calculation of Extra Mn Addition in the Recycling of Al-Si-Cu Aluminium Alloys
Authors: Ji Shou Xun , Gao Feng , Fan Zhong Yun
Published: November 2016

Iron contamination from scrapped materials is always a problem in producing high quality secondary aluminium alloys. Consequently, the iron removal during recycling of aluminium alloys is essential and important in industrial practice. This work aims to study the effect of extra Mn addition on the effectiveness and efficiency of iron removal during recycling. The thermodynamics assessment was carried out for Al-Si-Cu alloys to find out the variation of balanced iron and manganese in the liquid melt and in the sediment solid Fe-rich intermetallics with different levels of extra Mn addition. The effect of alloy composition and processing temperatures was investigated. The findings help to understand the capability and fundamentals of iron removal in aluminium alloys.
6000 Series Aluminium Alloy Strip Casting Using a Vertical Type Twin Roll Caster
Authors: Chen He , Li Yong , Li Jia Dong , Gao Guang Jun , Wang Zhao Dong
Published: November 2016

A vertical type twin roll caster with two side dams was used to cast aluminium alloy strip with a thickness of about 5mm at speed higher than 10m/min. The characteristics of the twin roll caster with two side dams are as follows: The diameter of the copper roll is 500mm, the width of the copper roll is 110mm and the thickness of the copper roll sleeve is 25mm.The maximum casting speed is up to 60m/min. Using the vertical type twin roll caster, a 4.5mm thickness of 6111 strip could be cast at a speed of 30m/min. The microstructure of the as-cast strip was equiaxed and spherical, not columnar. The mechanical properties of the strip casted from the vertical type twin roll caster were almost as same as that of the strip made from the conventional cast ingot.
The Study of Ingots and Deformed Semi-Finished Products of Al-Mg-Sc and Al-Cu-Li Alloys Using Diffraction Methods
Authors: Ovsyannikov Boris , Chikova Olga , Reznik Pavel
Published: November 2016

The influence of Al-Mg-Sc ingots and Al-Cu-Li semi-finished products heat treatment modes on structure, phase composition, and crystal structure was studied. Based on EBSD and EDS data, the difference of the sample microstructures was detected and the most favorable annealing mode for further deformation was presumed.
Microstructural Evolution of Al-Mn Based Alloy Fabricated by Vertical-Type High-Speed Twin-Roll Casting
Authors: Song Ram , Harada Yohei , Muraishi Shinji , Kumai Shinji
Published: November 2016

For decades, twin-roll casting has been applied for manufacturing aluminum alloy sheets. This conventional process contributes to make thin aluminum sheets from the molten metal directly. Recently, vertical-type high-speed twin-roll casting (HSTRC) has been developed with much higher casting speed rather than the horizontal-type. Some modifications such as feeding nozzle and water-cooling system of copper rolls contribute to increase cooling rates. This characteristic leads to many metallurgical advantages like grain refinement, super-saturation of alloying elements and fine distribution of secondary particles. The objective of this study is to investigate the constituent particles in HSTRC aluminum alloy. The commercial Al-Mn alloy strip was successfully fabricated by HSTRC. Clearly different microstructure was found in thickness direction. Many constituent particles observed along the grain boundaries/cell boundaries as well as inside of Al matrix on the surface area, while eutectic structure around globular grain boundaries was observed in mid-central area. The morphology as well as chemical compositions of the constituent particles were investigated.
About the Role of Hydrogen in Stress Corrosion Cracking of a 7xxx Aluminium Alloy (Al-Zn-Mg)
Authors: Oger Loïc , Andrieu Eric , Odemer Grégory , Peguet Lionel , Blanc Christine
Published: November 2016

The effects of hydrogen during stress corrosion cracking mechanisms (SCC) have been highlighted for many years but hydrogen trapping mechanisms are not yet well understood for 7xxx aluminium alloys. The 7046-T4 Al-Zn-Mg alloy has been chosen for this study because its low corrosion susceptibility allows hydrogen embrittlement (HE) to be more easily distinguished during SCC tests. Tensile stress tests have been carried out at a strain rate of 10-3 s-1 on tensile samples after an exposure at their corrosion potential in a 0.6M chloride solution for 165 hours under an imposed loading of 80%Rp0.2. The results were compared to those obtained for samples pre-corroded without mechanical loading applied and healthy specimens. A loss of mechanical properties was observed for the pre-corroded samples and presumably attributed to the absorption, the diffusion and the trapping of hydrogen which affects a volume under the surface of the alloy and modifies its mechanical properties. Scanning electron microscope (SEM) observations highlighted a strong effect of hydrogen on fracture modes. The ductile-intergranular initial fracture mode observed on the healthy samples was partially replaced for the pre-corroded samples by a combination of two main fracture modes, i.e. brittle intergranular and cleavage, in relation with the nature of the hydrogen trapping sites and local stress state.
Corrosion Characteristics of Al-B4C Metal Matrix Composites in Boric Acid Solution
Authors: Han Yu Mei , Chen X. Grant
Published: November 2016

The corrosion behavior of Al-B4C metal matrix composites in H3BO3 solutions with different Cl- contents was investigated using potentiodynamic polarization and zero resistance ammetry techniques. Results show that the corrosion of Al-B4C composites in H3BO3 solution increases with increasing B4C volume fraction in the composites. The main corrosion characteristic of Al-B4C composites in H3BO3 solution is the galvanic corrosion between Al matrix and B4C particles. In the galvanic couple, B4C particle acts as cathode and Al matrix acts as anode. The cathodic reaction is hydrogen revolution reaction, which controls the corrosion mechanism of Al-B4C composites. Pitting is not observed on the composite surface in the H3BO3 solution with zero Cl-. However, with addition of Cl- in H3BO3 solution, pitting occurs and the corrosion resistance remarkably decreases with increasing Cl- content. The corrosion resistance of Al-B4C composites in H3BO3 solutions is compared with that in the standard 3.5% NaCl solution.
Refinement of Primary Silicon Crystals by Novel P-Doped γ-Al2O3 Particles in Solidification of Hypereutectic Al-Si Alloys
Authors: Al-Helal Kawther , Stone Ian , Fan Zhong Yun
Published: November 2016

P-doped γ-Al2O3 was found to be a potent substrate to nucleate primary silicon whilst good modification of the eutectic matrix is retained during solidification of hypereutectic Al-Si alloys. On using P-doped γ-Al2O3 could be a perfect and clean source of P without additional impurities. The optical micrographs show that the morphologies of primary silicon crystals in solidification of Al-18Si alloy are changed from irregular coarse morphologies to fine regular particles. The average particle size of primary Si decreased from 52 μm to 25 μm and 22 μm in adding P-doped α-Al2O3 and P-doped γ-Al2O3 respectively. It was clear that P-doped γ-Al2O3 led to good refinement of primary Si and the modification effect on eutectic Si was retained in solidification of commercial purity Al-18Si alloy. Adding P-doped γ-Al2O3 give a good primary Si refinement to Al-18Si alloy if compared with the addition of P and using finer P doped γ-Al2O3 powder give narrower particle size range similar to that of adding P.
A Novel Methodology for Optimization of Properties, Costs and Sustainability of Aluminium Extrusions
Authors: Furu Trond , Østhus Rune , Søreide Jostein , Myhr Ole Runar
Published: November 2016

The present paper describes an innovative methodology that has been developed for optimization of product properties, production costs, and environmental impact in fabrication of aluminium alloys. The main idea is to represent each operation along the process chain by predictive models, which include material, mechanical, cost, and sustainability models. A multi-objective optimization platform is used to combine the models into a common software environment, which allows fully automatic simulations. The optimization tool runs the models in iterations until user-defined acceptance levels on properties, costs, and sustainability indices are obtained. In this paper, the methodology has been applied for fabrication of 6xxx-series aluminium extrusions. As a demonstration of practical relevance, the software tool was used to optimize mechanical properties and electrical conductivity by manipulation of alloy chemistry, processing parameters, and microstructure characteristics like grain structure, precipitates, dispersoids, and solid solution concentrations. At the same time material and production costs, as well as CO2 emissions along the value chain were attempted to be kept at minimum levels.
Modelling of the Age-Hardening Behavior in AA6xxx within a Through-Process Modelling Framework
Authors: Mao Feng Xin , Bollmann Christian , Brüggemann Thiemo , Liang Ze Qin , Jiang Hai Chun , Mohles Volker
Published: November 2016

The manufacturing of AA6xxx car body panels typically consists of rolling, ageing and forming processes. Thus, multiple simulation tools can be coupled to set up a through-process modelling (TPM) framework for predicting the evolution of microstructure and the final mechanical properties of these products. In order to realize such a TPM concept, various industrial processing phenomena were studied and modelled in the open innovation research cluster “Advanced Metals and Processes” (AMAP♯). This work focuses on the age hardening behavior which takes place during the industrial paint bake process. To reflect the microstructure evolution of this processing step, a multi-component precipitation model is developed. So far, the influences of thermomechanical processes, i.e. annealing temperature on the kinetics of MgxSiy precipitates during artificial aging were implemented. The precipitation model was linked to a yield strength model in order to simulate the evolution of mechanical properties within the TPM framework. For validation, the evolution of microstructure and mechanical properties of an AA6016 alloy during artificial ageing was investigated via transmission electron microscopy (TEM) and tensile testing. The simulation results are in agreement with experimental observations.
Effects of Heat Transfer Coefficients on Quenching Residual Stresses in 7055 Aluminum Alloy
Authors: Li Ya Nan , Zhang Yong An , Li Xi Wu , Li Zhi Hui , Wang Guo Jun , Yan Hong Wei , Jin Long Bing , Xiong Bai Qing
Published: November 2016

The quenching process can produce great residual stresses in 7055 aluminum alloy plates. The main factor that affects the quenching residual stresses is the heat transfer coefficient in the quenching process. In this paper, the heat transfer coefficients of spray quenching under different spray water flows were measured by using the inverse method, and the heat transfer coefficients of immersion quenching under different water temperatures were measured by the iterative method. The heat transfer coefficient increases as the spray water flow increases while decreases as the water temperature increases. The basic differences of water temperatures/spray water flows/quenching methods are the different heat transfer coefficients. According to the heat transfer coefficients results of immersion and spray quenching, an orthogonal test was carried out to study the effects of heat transfer coefficients in different temperature regions on the quenching residual stresses. The heat transfer coefficients in the range of 100oC ~200oC have a great influence on the quenching residual stresses, especially for the heat transfer coefficient near 150oC.
Multiscale Approach for the Damage Modeling of an Aluminum Casting Alloy with Stochastic Character
Authors: Andrieux Florence , Sun Dong Zhi , Burblies Andreas
Published: November 2016

Aluminum die casting components are widely used in vehicle constructions because they satisfy the conflicting requirements between weight reduction and mechanical property improvement. However, the analysis of deformation and damage behavior of aluminum cast components is very complex, since local mechanical properties in the components are inhomogeneous as a consequence of spatial distribution of microstructure. For crash simulation it is necessary to well predict the damage behavior which is strongly influenced by micro-defects especially by cast pores. The conventional continuum mechanics approaches often fail due to the statistical character of cast pores. In this work the Markov random field model (Ising) is used to describe the pore morphology. Markov random field classes are defined by porosity (macroscopic property) and equivalent pore size (microscopic property) and determined by micro computer tomography (CT) analysis.A multi scale approach was applied to map the results of the stochastic model to the FE models, which results in a distribution of porosity. A porosity dependent continuum model was developed based on results of representative volume elements with variation of porosity. It was shown that the continuum model with porosity distributions from the Ising model as initial conditions captures well the spatial material properties (i.e. fracture strain) and their variations in the bridging scale.
Effect of Electromagnetic Field on the Macrosegregation Behaviour of Al-Cu Alloy Ingot Prepared with Direct-Chill Casting Process
Authors: Zuo Yu Bo , Zhu Qing Feng , Li Lei , Xu Guang Ming , Cui Jian Zhong
Published: November 2016

A low frequency electromagnetic field was introduced into the direct chill (DC) casting process and the ingots of Al-Cu alloy were prepared to study the macrosegregation behaviour of the ingots under the influence of the electromagnetic field. The experimental results showed that there is an obvious positive segregation near to the surface and a negative segregation in the centre area of the ingot. Cu shows the highest segregation tendency among the main elements of Cu, Mg and Mn. Grain refiner element Ti shows a segregation trend opposite to that of Cu. With the application of electromagnetic field, the negative centreline segregation in the centre area of the ingot was evidently reduced although it didn’t show significant effect on the segregation near to the ingot surface. A significant grain refinement was also achieved with the application of electromagnetic field. The mechanism of the reduction of macrosegregation with electromagnetic field was also analyzed in the present work.