bluuebunny/crossref_metadata_2025 huggingface dataset:
Comme / comment du latin au français : perspectives diachronique, comparatiste et typologique
Authors: Aslanov Cyril
Published: August 2009

Résumé La comparaison entre les langues romanes révèle une intéressante dissymétrie entre les langues qui utilisent le même mot pour l’expression du subordonnant « comme » et de l’adverbe interrogatif « comment » et le français qui prend soin de distinguer les deux fonctions à travers l’emploi de comment , clairement distinct de celui de comme . Cette dissymétrie vient s’ajouter à la liste des divergences entre le français et les langues de la Romania continua , et mérite d’être examinée dans une perspective diachronique, afin de tenter de dégager les implications structurelles de la spécificité française sur ce point précis de la non-correspondance entre l’expression de « comment » et de « comme ». Pour ce faire, l’auteur combine les axes diachronique (du latin archaïque au français moderne), comparatiste (latin par rapport aux autres langues indo-européennes ; latin tardif à travers ses diverses spécifications ; ancien français par rapport aux autres langues romanes attestées au Moyen Age ; français moderne par rapport aux autres langues romanes modernes) et typologique (certaines langues, par exemple l’arménien, exprime « comment » par la combinaison de « comme » et de « quoi ? »).
Comment narratif
Authors: Defrancq Bart
Published: August 2009

Résumé Cette contribution se concentre sur un emploi particulier de comment que l’on trouve derrière un nombre restreint de verbes, tels que raconter , expliquer , voir ou dans des titres d’ouvrages ou d’articles. Cet emploi est appelé « narratif », dans la mesure où comment y dénote une série de procès résumés par la proposition à laquelle il appartient. La recherche exposée vise à déterminer la nature de la proposition qui accompagne comment narratif. Il apparaîtra qu’elle est à rapprocher des interrogatives enchâssées telles que définies dans Defrancq (2005), même si certains emplois ne sont pas enchâssés. La recherche, essentiellement basée sur corpus, permettra également de passer en revue les différentes propriétés syntaxiques et sémantiques qui font de comment narratif un cas spécial parmi ces interrogatives enchâssées.
« Comment n'y ai-je pas songé plus tôt ? », questions rhétoriques en comment
Authors: Desmets Marianne , Gautier Antoine
Published: August 2009

Résumé Dans cet article nous proposons une analyse constructionnelle des phrases interrogatives en comment dotée d’une lecture rhétorique (IRC). Au plan syntaxique, la structure interrogative présente des restrictions inhabituelles dans ses propriétés d’extraction. Au plan sémantique, l’IRC est une question partielle portant sur les conditions d’accessibilité à un monde où le noyau propositionnel de l’interrogative ( p ) est vrai, et non sur la manière d’un prédicat de p . La présence d’indices contrefactuels contraint le champ des réponses possibles et déclenche une lecture rhétorique qui véhicule l’assertion non (modalité)p . La conjonction de propositions contradictoires ( p et non (modalité)p )) provoque un conflit entre le monde des attentes du locuteur et celui dans lequel p est envisagée comme vraie ; conflit qui est le support d’attitudes émotives telles que la surprise ou l’indignation. Au plan pragmatique, les IRC sont des actes de langage complexes qui associent un commitment questionnant du locuteur à une demande adressée à l’interlocuteur de se commettre au déni de p .
Comment et les expressions indéfinies en n'importe et que ce soit
Authors: Pierrard Michel
Published: August 2009

Résumé Le français a produit deux séries d’« expressions indéfinies » : les formes « négativement indéfinies », où la proforme indéfinie est reprise par une forme en que ce soit ( je n’ai pas vu qui que ce soit ) et les formes « positivement indéfinies » en n’importe ( n’importe qui doit respecter la loi ). Contrairement à ce qui s’est passé dans d’autres langues (cf. angl. whenever / however et ndl. wanneer ook / hoe ook ) et à ce qui était encore possible en ancien ou en moyen français, (1) a) Quant que ce soit , ou tost ou tart. (Barb.; T.L., 2 : 27) b) Si suis-je trompé si guere d’autres donnent plus à prendre en la matiere : et comment que ce soit , mal ou bien, si nul escrivain l’a semée, ny guere plus ... (Montaigne, Essais , livre 1, chap. 39) le français moderne a restreint les expressions en quand et en comme / comment à la deuxième série. L’étude montre la spécificité de comment par rapport à qui , quoi , etc., et explique pourquoi comment n’entre pas dans l’expression indéfinie ... que ce soit , mais uniquement dans n’importe ... Elle décrit ensuite le fonctionnement sémantique de n’importe comment . French uses two types of indefinite constructions: the « negative indefinites », in which the indefinite proform qu- is completed by the hypothetical concessive clause que ce soit (e.g. je n’ai pas vu qui que ce soit ) and the « positive indefinites », introduced by the verbal element n’importe (e.g. n’importe qui doit respecter la loi ). In contrast to similar constructions in other languages ( cf . English whenever / however and Dutch wanneer ook / hoe ook ) and in Old and Middle French (1) a) Quant que ce soit , ou tost ou tart. (Barb.; T.L., 2 : 27) b) Si suis-je trompé si guere d’autres donnent plus à prendre en la matiere : et comment que ce soit , mal ou bien, si nul escrivain l’a semée, ny guere plus ... ( Montaigne, Essais, livre 1, chap. 39)
Et comment !, entre exclamation et assertion
Authors: Moline Estelle
Published: August 2009

Résumé Et comment ! peut occuper une position finale détachée ( Je m’assieds comme toi sur les traditions, et comment ! , Abellio) ou, en dialogue, constituer une réplique assertive autonome ( C’était faux ? / Et comment ! , Malraux). Il peut également être suivi d’une conjonctive en que , laquelle reprend, le cas échéant, le contenu propositionnel de l’énoncé ayant provoqué son énonciation ( Va donc gueuler à la cuisine / Et comment que j’vais gueuler ! , Fallet). De ce fait, Et comment ! s’apparente aux adverbes assertifs ( Effectivement , Evidemment , etc ) et évaluatifs ( Heureusement , Malheureusement , etc. ), qui présentent des propriétés analogues. A la différence de ces adverbes cependant, Et comment ! possède une valeur exclamative, dans la mesure où il est en quelque sorte « arraché » à l’énonciateur par la prédication antérieure (emploi relatif), ou par l’acte de langage, en l’occurrence une demande d’assentiment, accompli par l’interlocuteur. Cet emploi assertif de et comment ! est corrélé à l’emploi prototypique de l’adverbe interrogatif comment , dont il est issu par un processus de grammaticalisation.
Les sionismes au 20e siècle, entre contextes et contingences
Authors: Charbit Denis
Published: August 2009

Résumé Le sionisme fait souvent l’objet d’éloges et de condamnations qui ont en commun de l’expulser hors de l’histoire, alors même qu’il est un produit de l’histoire du 19 e et du 20 e siècle. Né dans le contexte de l’émancipation, du printemps des peuples et de l’antisémitisme, son développement ultérieur sous la forme de l’État d’Israël tient largement aux événements clés du 20 e siècle : la première et la seconde guerre mondiale, la décolonisation et la chute de l’Union soviétique. L’article examine la question récurrente de l’assimilation du sionisme au colonialisme et montre ensuite comment un projet, qui fut révolutionnaire pour le peuple juif après deux mille ans de conscience exilique, a échappé à la tentation totalitaire de nombre de projets révolutionnaires dont le sionisme fut contemporain.
Construction nationale et discrimination au Proche-Orient
Authors: Bourmaud Philippe
Published: August 2009

Résumé La discrimination nationale est une notion dont le sens varie. Elle prend cependant toute sa signification dans le cadre des États nations. La transition de l’Empire ottoman, un État impérial multi-ethnique, aux États créés comme mandats de la Société des nations, fut l’occasion de ce phénomène. La discrimination était opérée différemment et avec des objectifs variables d’un pays du Proche-Orient à un autre, selon l’équilibre politique au sein des élites locales et selon la vision sociopolitique qui avait façonné ces États. Pendant les Mandats et après les indépendances, les nouveaux États ont eu tendance à sélectionner les communautés qu’ils étaient prêts à accueillir parmi leurs citoyens. Les membres d’autres communautés, moins fortunées, furent dénationalisés par de multiples moyens, surtout par l’émigration et par les politiques d’expulsion. Les Palestiniens, dans les différents États et territoires qu’ils habitent, constituent un exemple des processus d’exclusion par discrimination nationale.
De la région frontière à la ligne frontière
Authors: Mizrahi Jean-David
Published: August 2009

Résumé Lorsque la France s’installe en Syrie et au Liban au lendemain de la première guerre mondiale, elle doit faire face à une profonde insécurité. En particulier, les confins méridionaux de la Syrie mandataire, au contact d’une Transjordanie encore balbutiante, représentaient une zone particulièrement sensible. Expliquer comment cette région frontière devint une ligne frontière permet non seulement de comprendre comment le Moyen-Orient moderne est né, mais permet aussi de comprendre comment ces nouvelles frontières ont affecté les représentations, à la fois géographiques et politiques, que les populations locales avaient d’elles-mêmes.
Frontières et pouvoir d'État
Authors: Altuğ Seda , White Benjamin Thomas
Published: August 2009

Résumé Le présent article se propose d’étudier la délimitation de la frontière turco-syrienne dans les années 1920 et 1930, afin d’illustrer le rapport dynamique entre le développement des frontières contemporaines – lignes précises et fixes, délimitant des territoires bien définis – et le développement de l’État nation. En Turquie, la définition de la frontière faisait partie de l’extension du pouvoir du nouvel État républicain sur le territoire qu’il revendiquait. La frontière jouait aussi un rôle important dans le discours nationaliste de la République, puisqu’elle servait à définir non seulement le territoire de l’État, mais aussi les groupes et populations qu’il fallait en exclure. En Syrie, si la délimitation de la frontière jouait un rôle identique dans l’extension du pouvoir de l’État mandataire, elle jouait un rôle discursif davantage dans le discours nationaliste arabe syrien que dans le discours de la puissance mandataire.
Identifications nationales et construction des frontières
Authors: Sfeir-Khayat Jihane
Published: August 2009

Résumé L’article se penche sur l’identification des Palestiniens durant les premières années de leur exil libanais (1947-1958). Il s’agit d’abord de revenir sur la mise en place des frontières séparant le Liban de la Palestine mandataire et de l’État d’Israël post-1948. Il est ensuite question d’étudier tout un ensemble de politiques qui définissent l’attitude institutionnelle libanaise à l’égard d’une population étrangère. L’article se termine par une analyse de l’impact des frontières sur le façonnement des nouvelles identités palestiniennes et libanaises, de la redéfinition de l’espace dans lequel s’étaient construites les identités des habitants de part et d’autre de la ligne séparant le Liban sous mandat français de la Palestine sous domination britannique, du Liban indépendant avec le nouvel État d’Israël.
Les identités chiites au Liban-Sud
Authors: Chaib Kinda
Published: August 2009

Résumé L’appartenance au système confessionnel libanais apporte aux chiites une certaine reconnaissance en tant que groupe constitué, mais ce constat ne nous informe que peu sur la façon dont ils se définissent comme chiites aujourd’hui. Nous prendrons l’exemple du Liban-Sud qui a une histoire particulière, tant par l’ancienneté de la présence chiite que par son contact direct avec l’occupation. Après avoir posé quelques jalons de l’histoire des chiites au Liban, nous verrons comment s’est opérée leur prise de conscience communautaire, entre adhésion à des partis de gauche et affirmation d’une identité confessionnelle (re)découverte à la faveur de la guerre civile et de l’occupation israélienne. L’iconographie et les cimetières de villages, à travers l’étude de la mise en scène des martyrs, permettront ensuite de comprendre comment, entre contrôle partisan et ancrage local, les chiites du Liban-Sud se vivent comme chiites depuis la libération de la région en 2000.
Guerre, rupture et frontière identitaire dans le Sud du Mont-Liban
Authors: de Clerck Dima
Published: August 2009

Résumé Cet article fait le point sur les rapports intercommunautaires druzo-chrétiens dans le Liban d’après-guerre et se penche sur les conditions et les difficultés d’une réintégration des chrétiens dans leur milieu d’origine après plus de quinze ans de séparation avec leurs voisins de toujours, depuis leur expulsion hors de la Montagne en 1983. Les relations druzo-chrétiennes d’avant-guerre sont revisitées, en soulignant qu’elles étaient caractérisées plus par une proximité que par la mixité. Lors de la guerre de 1975-1990, le code tacite de sociabilité forcée qui régulait ces relations et prévenait la violence n’a pas été suffisant pour empêcher la rupture entre druzes et chrétiens. Les préjugés qu’ils nourrissent sont le fruit de leur cohabitation historique et de leurs mémoires affrontées. L’installation massive, souvent forcée des chrétiens en ville et leur adoption de tendances citadines a suscité de leur part un relâchement des pratiques propres au milieu rural restées chères aux druzes.
Vers un féminisme politique hors frontières au Proche-Orient
Authors: Latte Abdallah Stéphanie
Published: August 2009

Résumé Cet article a pour objet l’histoire du féminisme jordano-palestinien depuis les années 1950, entendue comme un cas d’étude exemplaire des recompositions des organisations féminines au Proche-Orient. Depuis les années 1980, ce féminisme a subverti les frontières partisanes, s’est émancipé du nationalisme, avant de s’approprier puis de redéfinir les nationalismes, palestinien puis jordanien, au sein desquels il s’est forgé des années 1950 aux années 1980. Ce féminisme s’est aussi démocratisé en s’ouvrant aux classes moyennes et populaires. Ainsi, contrairement à l’idée d’un renforcement du conservatisme social dans la région au cours des années 1980, qui voit l’émergence de l’Islam politique dans la sphère publique régionale, c’est à partir de cette période que commencent à être formulées des revendications plus radicalement féministes. Celles-ci sont liées à l’émergence de nouvelles actrices militantes, séculières et islamiques, et aux relations qu’elles nouent. Elles sont le plus souvent issues de groupes sociaux ayant moins eu accès à la représentation sociale et politique. Ce féminisme politique hors frontières peut être qualifié de postpartisan, postnationaliste et postislamique. Il s’emploie à contester les violences et les situations de minorités sociales et politiques, à travers la notion large de discrimination (tout à la fois sexuelle, sociale et politique), replaçant au cœur du politique une question démocratique élargie, de la sphère intime et privée à la place des groupes sociaux et nationaux au niveau régional et mondial.
Health Literacy Issues Among Women with Visual Impairments
Authors: Harrison Tracie C. , Mackert Michael , Watkins Casey
Published: August 2009

The purpose of this secondary analysis using qualitative description was to explore health literacy using the health care experiences of women with permanent visual impairments (VIs). Interviews were analyzed from a sample of 15 community-dwelling women ages 44 to 79 with permanent VIs who had participated in a larger grounded theory study. The 15 women were interviewed twice; the audio-recorded interviews were then transcribed verbatim and analyzed using qualitative content analysis. Using the Institute of Medicine's definition of health literacy, the women's experiences were categorized into their ability to obtain, process, and understand health information. Their perceptions of the factors that influenced their health literacy were also explored. The women voiced that barriers to their ability to gain information in a format amenable to their processing skills, combined with barriers arising from health care providers' attitudes, undermined their ability to build health literacy capacity.
Use of Lay Educators to Overcome Barriers to Research with Black Older Adults: A Case Study Using an Alzheimer's Disease Center
Authors: Souder Elaine , Terry Tanya Laws
Published: August 2009

There are many well-documented barriers to recruitment of Black participants in clinical research. This is of concern in Alzheimer's disease (AD) research because of the escalating rate of AD in this group, the increasing proportion of minority groups, and their low rate of research participation. Our Alzheimer's Disease Center (ADC) Black Advisory Board recommended we try a lay educator (LE) approach to bridge the gap between the community and university-based research center. As a result, our LE program contributed to a significant increase in the number of AD presentations given to the Black community. Although the number of Black participants enrolled in our ADC program increased from 12% to 25%, the process was challenging. However, the LE program led to significant progress in our efforts to meet our enrollment expectations, fostered links between the university and the Black community, and furthered our understanding of the barriers created by our recruiting practices.
Question Asking by Family Caregivers in Hospice Interdisciplinary Team Meetings
Authors: Wittenberg-Lyles Elaine , Oliver Debra Parker , Demiris George , Washington Karla T. , Regehr Kelly , Wilder Heidi M.
Published: August 2009

This article reports findings from a pilot study that enabled family caregivers to use videophone technology to participate in hospice interdisciplinary team meetings. The goal of the study was to ascertain which issues were important to caregivers and the hospice team. A qualitative content analysis of video-recorded team meetings between team members and caregivers was conducted. In a sample of 12 caregivers in 36 discussions, caregivers asked a total of 137 questions, with the majority being Yes/No questions (45.1%), primarily used to seek clarification (19.6%). Hospice staff asked 396 questions, with the majority consisting of Yes/No questions (66.5%), mainly used to ask about the overall condition of the patient (22.2%). Data from this study suggest that when given the opportunity to participate in hospice team meetings, caregivers will ask questions of hospice staff. In addition, in light of prior research, this study's findings suggest that caregivers may have questions that go unaddressed, specifically regarding pain and medication.
The Cumulative Influence of Conflict on Nursing Home Staff: A Computer Simulation Approach
Authors: Abrahamson Kathleen , Anderson James G. , Anderson Marilyn M. , Suitor J. Jill , Pillemer Karl
Published: August 2009

Nursing staff burnout is a significant challenge in the delivery of nursing home care. Using a representative sample of nursing staff working within the nursing home setting, our analysis addressed the influence of conflict with residents' families on the burnout experience of staff. Through the use of computer simulation modeling we were able to assess the cumulative effects of conflict between staff and families. Findings indicated that conflict with the residents' families increased both burnout and dissatisfaction among nursing staff. The burnout experience of nursing staff peaked with initial episodes of conflict, then leveled off as simulated conflict with family members continued. Because previous research has indicated that burnout tends to peak early in nurses' career cycle, the finding that initial episodes of conflict have a strong influence on nursing staff burnout highlights the importance of interpersonal conflict within nursing homes in both individual and institutional outcomes.
Ten Commandments of Faith-Based Recruitment
Authors: Lefler Leanne L.
Published: August 2009

Recruitment of older adults for clinical research, especially racial/ethnic minorities, is challenging at best. This article reports the author's experience and reviews current literature regarding faith-based methods to recruit older Black and White women for research. Her work and the literature review suggest 10 major recommendations for faith-based recruitment. Recommendations include: Select only faith institutions with religious leaders who actively advocate and collaborate; select key advisors or “insiders” to facilitate and customize the study; use culturally appropriate and age-sensitive recruitment and study materials; use faith institution facilities and promote access; use incentives; increase “face time”; use existing faith groups to encourage peer support; make it a social event and make it fun; provide personal benefit to participation; and customize spirituality. Involvement with faith institutions may be essential to reach groups who have been underrepresented in research.
Going the Distance: Overcoming Challenges in Recruitment and Retention of Black and White Women in a Multisite, Longitudinal Study of Predictors of Coronary Heart Disease
Authors: McSweeney Jean C. , Pettey Christina M. , Fischer Ellen P. , Spellman Alisa
Published: August 2009

High recruitment and retention rates are hallmarks of scientifically rigorous longitudinal research. However, recruitment and retention are challenging, especially with older adults and minorities. In this article, we discuss strategies that have enabled us to retain more than 80% of both Black and White women in a 5-year observational study. To overcome challenges such as staff turnover and introduction of computerized record systems, we developed a time-saving handout, streamlined procedures for documenting contact information, and motivated site staff through weekly personal contact. We responded to problems with mailed privacy consent forms by garnering approval for verbal consent that allowed immediate response to participants' questions. In addition to standard steps to minimize attrition, we encouraged ongoing participation with personal letters following interviews, “refrigerator reminders” of the next interview date, and “missing you” letters following missed appointments. We believe these and other strategies described in this article were responsible for our high retention rate.
Mobile Prototyping Platforms for Remote Engineering Applications
Authors: Henke Karsten , Ostendorff Steffen , Volkert Thomas , Mitschele-Thiel Andreas
Published: September 2009

This paper describes a low-cost mobile communication platform as a universal rapid-prototyping system, which is based on the Quadrocopter concept. At the Integrated Hardware and Software Systems Group at the Ilmenau University of Technology these mobile platforms are used to motivate bachelor and master students to study Computer Engineering sciences. This could be done by increasing their interest in technical issues, using this platform as integral part of a new ad-hoc lab to demonstrate different aspects in the area of Mobile Communication as well as universal rapid prototyping nodes to investigate different mechanisms for self-organized mobile communication systems within the International Graduate School on Mobile Communications. Beside the three fields of application, the paper describes the current architecture concept of the mobile prototyping platform as well as the chosen control mechanism and the assigned sensor systems to fulfill all the required tasks.
Effect of LaCl3 on the Properties of LAS Ceramics
Authors: Li Yong , Zhang Xiao Li , Li Ling , Wang Hong Sheng , Jiang Hong Yi
Published: September 2009

In this research, different amounts of LaCl3 were added to the lithium aluminum silicate (LAS) ceramics and the sample powder was prepared by sol-gel method. The effect of LaCl3 on the density, bending strength and the thermal expansion of the obtained ceramics was mainly investigated because LaCl3 is heavier than the lithium aluminum silicate (LAS) ceramics and the superfluous of La2O3 can be introduced into the sol solution.
Investigation of Bipolar Resistance Switching Properties in SrTiO3 Thin Films with Symmetric Electrodes Structure
Authors: Yu Wei Dong , Li Xiao Min , Zhang Yi Wen , Yang Rui , Wang Qun , Chen Li Dong
Published: September 2009

A noncrystalline SrTiO3 (STO) thin film was grown on Pt/Ti/SiO2/Si substrates by pulsed laser deposition. The Pt thin film was deposited on STO film as top electrode, forming a symmetric structure (Pt/STO/Pt) to exclude the influence of the electrical difference in STO-electrode interfaces. It was found that a stable bipolar resistive switching was obtained in this structure. In a current sweep, an obvious S type negative differential conductance (NDC) phenomenon was found in both polarities. And in a voltage sweep, no NDC was observed due to the current control mechanism of S type NDC effect. The possible mechanism of this effect is discussed preliminarily.
Laser Energy Dependent Structure of Pulsed Laser Deposited Barium Dititanate Films
Authors: Li L. , Wang Chuan Bin , Shen Qiang , Zhang Lian Meng
Published: September 2009

Barium dititanate (BaTi2O5) films were prepared on MgO (100) substrate by pulsed laser deposition under various laser energy densities. The effect of laser energy on crystallinity, orientation and surface morphology was investigated. The preferred orientation of the as-deposited films changes from (710) to (020) with decreasing laser energy, and the surface morphology is different depending on laser energy too. The b-axis oriented BaTi2O5 film could be obtained at the laser energy density of 2J/cm2, where the film shows a dense surface with an elongated granular texture.
Preparation of TC4-LY12 Joint by Vacuum Diffusion Welding
Authors: Zeng Hao , Luo Guo Qiang , Shen Qiang , Wang Chuan Bin , Zhang Lian Meng
Published: September 2009

TC4-LY12 welding joint are fabricated by vacuum diffusion welding. The bonding phases are confirmed by X-Ray Diffraction (XRD), the morphology of samples and chemical composition are evaluated by Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectrometer (EDS) analysis, the mechanical property is tested by tensile strength measurement. The XRD patterns show that the main intermetallic compounds formed in the transition zone are Ti3Al, TiAl and TiAl3. Combining the fracture surfaces morphology and element analysis, the bonding mechanism of TC4-LY12 joint is attributed to the inter-diffusion between Ti and Al atoms. The initial phase formed during the reaction is TiAl3 due to the diffusion of titanium atoms into aluminum substrate; with the process of the reaction, Ti3Al and TiAl phases appear gradually with the atomic ratio of 1:1.The tensile strength of the joint increases remarkably with increase of temperature and takes a maximum value (~60MPa) when the welding temperature is 550°C.
Fabrication of Mg-W System FGM with Density Gradient by Hot-Press Sintering
Authors: Wei Qin Qin , Luo Guo Qiang , Shen Qiang , Zhang Lian Meng
Published: September 2009

Functionally graded material (FGM) with density gradient has showed great potentials as flier-plate for creating quasi-isentropic compression waves. In order to obtain a FGM with low density in the front face and with a wide density range, the Mg-W system gradient material is designed, and the power metallurgy method and hot-press (HP) sintering are chosen for its fabrication. The sintering of Mg-W alloys is studied at relative low temperatures and the processing of densification is mainly investigated. It is found that, up to 85wt%W, the approximately wholly dense Mg-W system alloys are achieved at 620°C for 1.5 hours under a pressure of 100MPa. Mainly the mechanical mixtures of Mg and W are formed in Mg-W alloys. And the Mg-W alloys are fully densified at 620°C due to the conglutination of Mg, a small amount of which are melting in this experimental condition. Finally, the Mg-W system FGM with a wide density gradient from 1.74g/cm3 to 7.56 g/cm3 within the 3.50mm thickness range is fabricated at the sintering parameter of 620°C-100MPa-1.5hours.
Quasi-Isentropic Compression Characters of Flier-Plates with Graded Impedance
Authors: Wang Chuan Bin , Shen Qiang , Zhang Lian Meng
Published: September 2009

Two types of flier-plates with graded impedance, namely multi-ply and pillow, which had different variations of impedance’s distribution, were prepared in the present study. Wave profiles with a small initial jump followed by a slowly-rising front were generated by using both types of the flier-plates, indicating that quasi-isentropic loading had been realized. The characters of wave profiles generated by these two flier-plates were different from each other, which were in accord with their impedance distribution and microstructure. The pillow flier-plate created a more smoothly-rising front than that of multi-ply flier-plate, leading to better loading effect.
Numerical Simulation of Dominating Control Factors of Thermal Protection FGM’s Effective Thermal Conductivity
Authors: Liu Qi Wen , Zhang Bei , Zhang Lian Meng
Published: September 2009

Thermo-shock resistance of the thermal protection materials is affected by its heat, mechanical properties, and various environmental factors. Therefore, it is very essential to understand which factors take great roles in affecting thermo-shock resistance and how much they affect, when designing the thermal protection materials. This paper applies the experimental scheme designed by means of orthogonal design and implement numerical experiments with the numerical simulation technology; and analyses the factors which affect the thermo-shock resistance of FGM material, such as choice of ceramic material, specimen thickness, number of layers, and heat flux loading; then identifies the dominating factors controlling the thermal shock resistance of thermal protection materials.
Effect of Sintering Schedule on the Microstructure of Carbon Nanotubes Reinforced Alumina Fabricated by SPS Method
Authors: Huang Li Wei , Fu Zheng Yi , Zhang Jin Yong , Wang Wei Min , Wang Hao , Wang Yu Cheng , Niihara Koichi , Lee Soo Wohn
Published: September 2009

Carbon nanotubes reinforced alumina was fabricated by spark plasma sintering method. When adding 0.2wt% nanotubes, the fracture toughness of the composites prepared increases 19% compared with the pure alumina ceramics. The effect of sintering schedule on microstructure and mechanical properties is investigated systematically. Microstructure studies reveal that at high sintering temperature, the nanotubes tend to gather in the gaps surrounded by three or more grains in a flocculent state, which leads to poor mechanical properties. Raman spectrum indicates that long sintering duration may cause serious nanotubes destruction and lower the mechanical properties.
Effect of CaO on Sintering and Crystallization of CaO-Al2O3-SiO2 System Phosphorus Slag Glass-Ceramic
Authors: Cheng Jin Shu , Qiu Hui Guang , Tang Li Ying
Published: September 2009

Much phosphorus slag which is produced every year, not only brings about the resource waste, but also results in the pollution of the environment. In the paper, phosphorus slag was added into the glass-ceramics of CaO-Al2O3-SiO2 system. Through increasing the CaO content of CaO-Al2O3-SiO2 system glass-ceramics and keeping constant content of the phosphorus slag, the phosphorus slag glass-ceramics were obtained. The optimum compositions of CaO-Al2O3-SiO2 system phosphorus slag glass-ceramics was obtained through careful analysis based on X-ray diffraction (XRD), scanning electron microscopy (SEM) and other measuring methods. The results showed that with increasing of CaO content, the leveling temperature, the crystal content and the densities of samples were gradually increasing, however, the leveling temperature range was gradually narrowing. When the content of phosphorus slag was 30wt%, the addition of 17wt%CaO was more reasonable. The main phase of phosphorus slag glass-ceramic was β-wollastonite. The leveling temperature range of glass-ceramic was 1130-1140°C and the holding time was 2 hours.
Carbothermal Reduction and Nitridation Synthesis of γ-AlON Powder under High Heating Rate
Authors: Peng Ding , Wang Hao , Wang Wei Min , Wang Yu Cheng , Fu Zheng Yi
Published: September 2009

In this paper, a carbothermal reduction and nitridation (CRN) synthesis for cubic aluminum oxynitride (γ-AlON) powders is reported. The CRN reaction was conducted via a two-step synthesis procedure at a heating rate of 100 °C/min. In the first step, the mixture of fine γ-Al2O3 and soluble starch was annealed at 1550~1580 °C for different duration. It is found that the mixture of α-Al2O3 and AlN with an appropriate ratio can be obtained by CRN reaction. The content of AlN in mixture is closely related with the reaction condition. In the second step, the as-received mixture of α-Al2O3 and AlN was heat-treated at 1700 °C for 10 min. The single phase γ-AlON powders with particle size less than 3 µm were obtained.
Effect of Nd2O3 and Sm2O3 on the Microstructure and Electrical Properties of WO3 Capacitor-Varistor Ceramics
Authors: Wang Tian Guo , Shao Gang Qin , Zhang Wen Jun , Li Xi Bao
Published: September 2009

The effect of Nd2O3 and Sm2O3 on the microstructure, nonlinear electrical properties, and dielectric properties of WO3-based ceramics was investigated. The dopant Nd2O3 and Sm2O3 can promote the grain growth of WO3 grains. It was also found that Nd2O3 and Sm2O3 can reduce the breakdown voltages values of WO3-based ceramics effectively, but do not strongly influence the nonlinear values. The nonlinear coefficient of doped samples was 2-3 and the barrier voltage was very low with the value of 0.04-0.08 V. Through impedance analysis, it can be found that those rare earth ions have a great influence on the dielectric properties. The dielectric constant of doped samples was higher than that of undoped samples, and the high dielectric constant makes them suitable as capacitor-varistor materials. The theory of defects in the crystal lattice was introduced to explain the nonlinear electrical behavior of the WO3-based varistor ceramics.
Characterization of Transparent Conducting Al:ZnO Thin Films Deposited by Chemical Spray Pyrolysis
Authors: Mahajan C.M. , Godbole A.G. , Gumfekar S.P. , Sonawane S.H. , Takwale M.G.
Published: September 2009

Nanocrystalline undoped and Al doped ZnO thin films were synthesized by the chemical spray pyrolysis of Zinc acetate and Aluminium chloride solution. The optoelectronic properties of undoped and Al:ZnO films were investigated. The XRD patterns of films were preferably oriented along c-axis [0 0 2] plane with the hexagonal wurtzite structure. The Al-doping caused no additional X-ray diffraction peaks when compared with XRD of undoped film, indicating Al2O3 content was below the detection limit. The crystallite size of undoped and Al doped film was 48 nm and 51nm respectively, as measured from X-ray diffractogram. The films are of high optical transmittance (≥ 90%). The resistivity of the film was found to decrease because of Al doping. The dark resistivity measurement for Al:ZnO film was of the order of 10-3 Ω-1cm-1. The band gap energy of the film was found to vary from 3.25 to 3.32eV indicating the Moss Burstein shift. Al:ZnO films can be used as transparent conducting oxide layers for photovoltaic applications.
Magnetic, Electronic - and Magneto - Transport Properties of Nanocrystalline Nd0.6Sr0.4MnO3 Manganites
Authors: Sourav Kundu , Tapan Kumar Nath
Published: September 2009

We have reported in this paper, the effect of grain size in Nd0.6Sr0.4MnO3 .We have investigated the effect of grain size on metal-insulator transition and Curie temperature. We have also reported here the variation of low field magnetoresistance with temperature and grain size. We have observed that the Curie temperature increases monotonically with particle size. The metal insulator transition temperature initially increases with particle size and then gets fixed to a certain value. In these Nd0.6Sr0.4MnO3 nanometric systems, any significant variation of magnetoresistance with particle size is not observed.
Structural and Magnetic Properties of BaMg2Fe10O19 Hexaferrite Particles
Authors: Jotania Rajshree B. , Chauhan Chetna , Menon Shobhana , Jotania Kanti
Published: September 2009

BaMg2Fe10O19 hexaferrite particles were synthesized by using a Stearic acid gel method. The prepared Ba-Mg hexaferrite particles were calcinated at Microwave frequency (2.45 GHz, power 900W, 5 min.) as well as at 650°C, 750°C, 850°C and 950°C. Decomposition behavior and the phase associated therein are investigated by means of thermal analysis (DTA, TGA, DSC) and XRD, respectively. The X-ray diffractograms of prepared samples calcinated at 650°C, 750°C, 850°C and 950°C show the presence of M and α- Fe2O3 Phases, whereas the sample heated in a microwave oven shows only single M-phase. Surface morphology of nonporous particles has been examined by using SEM. The samples prepared by conventional heat treatment produces agglomerated clusters of various size particles whereas, the sample heated in a microwave oven shows separate particles with size ranging from 80-240nm. There is significant change in crystallite size of the resultant Ba-Mg hexaferrite particles prepared at microwave frequency. It was observed that heat treatment condition plays a very crucial role in controlling morphology of prepared Ba-Mg hexaferrite particles. Room temperature magnetic measurements were carried out using VSM. Magnetic study reveals that prepared BaMg2Fe10O19 particles possess single magnetic domains.
Direct Synthesis of Nano Alumina from Natural Bauxite
Authors: Manivasakan P. , Rajendran V. , Rauta P.R. , Sahu B.B. , Panda B.K.
Published: September 2009

The nano alumina have been synthesised employing a novel eco-friendly route from natural bauxite ore. The synthesis of alumina powder from natural bauxite is of great interest owing to the fact that it enables mass production without the use of expensive chemical resources and processing techniques. Employing the Bayer process, synthesis of nano alumina has been made from natural bauxite followed by sol-gel route. The ultra fine alumina powder with high surface area is obtained through the digestion of gel followed by sintering. The size of the particle and its morphology was controlled by calcination temperature and processing time. The crystallite size of the nano alumina powder has been measured using XRD pattern and the FTIR spectrum of nano powder after calcination at different temperatures (873 K and 1273 K) were measured. The results from the energy dispersive X-ray analysis (EDAX) and morphological studies reveal interesting informations. The observed results indicate that one can control the particle size by controlling the aging and calcination temperature. The obtained results indicate that the above process technique is an unique method for the preparation of nano alumina (Al2O3) from natural source such as bauxite.
Corrosion Behaviour of Amorphous and Nanocrystalline Ti60Ni40 in Aqueous HNO3 Solution
Authors: Mathur Shubhra , Vyas Rishi , Dolia S.N. , Sachdev Kanu , Sharma S.K.
Published: September 2009

Potentiodynamic polarization studies were carried out on amorphous, nanocrystalline and crystalline states of the alloy Ti60Ni40 in 0.1 M HNO3, 0.5 M HNO3 and 1 M HNO3 aqueous solutions at room temperature. It was observed that the amorphous state exhibited higher corrosion current density than that by the nanocrystalline state. These results are corroborated by the weight loss studies performed on the different structural states of Ti60Ni40 alloy in 0.1 M HNO3, 0.5 M HNO3 and 1 M HNO3 aqueous media. Thus the nanocrystalline state is least prone to corrosion than the amorphous and the crystalline states.
A Comparative Study of Corrosion Behaviour of Amorphous and Nanocrystalline Ti60Ni40 in 0.5 M H2SO4 and 0.5 M HNO3 Aqueous Media
Authors: Mathur Shubhra , Vyas Rishi , Dolia S.N. , Sachdev Kanu , Sharma S.K.
Published: September 2009

Corrosion studies were carried out using potentiodynamic polarization method on amorphous, nanocrystalline and crystalline states of the alloy Ti60Ni40 in 0.5 M H2SO4 and 0.5 M HNO3 aqueous media at room temperature. The nanocrystalline state of Ti60Ni40 was obtained by removing about 10 μm from the air side surface (crystalline state) by polishing. The presence of nanocrystalline phase was confirmed by X-ray diffraction (XRD). It was found from polarization results that the corrosion current density was higher in the amorphous state than in the nanocrystalline state in both 0.5 M H2SO4 and 0.5 M HNO3 aqueous media. These results are corroborated by the weight loss studies which were carried out in both of these media. Results are discussed in the paper in the light of data reported in the literature on similar type of alloys.
Spectroscopic Analysis and Synthesis of Wide Band Gap CdS Quantum Dots Using Colloidal Synthesis Technique at Low Temperature
Authors: Hashmi Lubna , Qureshi M.S. , Dubey R.N. , Malik M.M. , Alim Ishrat , Siddiqui A.H.
Published: September 2009

A broad range of II-VI materials has been investigated in order to produce light in the full visible range for optoelectronic applications. The present investigation was carried out for the spectroscopic analysis and synthesis of wide band gap cadmium sulfide nanoparticles. Large-band gap semiconductors have the added advantage in that; they can support higher electric field before breaking down, which means that they can be used for high-power electronic devices.Synthesis has been carried out using colloidal synthesis technique at low temperature. The size, stabilization and optical properties were studied using UV-vis Spectrophotometer and Spectroflourometer. Further, the structural studies of synthesized powder were carried out using X-ray diffraction technique; which also confirms the formation of desired product. The capping ligand and the impurities present in the sample were characterized by Fourier transform infra red spectroscopy. Synthesized CdS powder dispersed in aqueous media gave the value of 193 nm for the onset wavelength using UV-vis spectrophotometer, which is significantly blue-shifted compared to bulk CdS and shows the quantum confinement effect. From the onset wavelength the radius of CdS quantum dot calculated using the Brus equation was found to be ca. 0.7 nm.
Synthesis and Nondestructive Characterization of Cr2O3 Nanoparticles-PVA Suspensions
Authors: Singh D.K. , Yadav R.R. , Pandey D.K.
Published: September 2009

Nanoparticles of chromic oxide (Cr2O3) are widely used in many fields serving as catalysts, wear resistance materials, and advanced colorants. By the reaction system of CrO3 and PVA in aqueous solution, Cr2O3 nanoparticles were prepared via hydrothermal synthesis. We have taken sucrose as reducing agent. The products were loosely agglomerated Cr2O3 particles of 30-80 nm in average particle size calculated from Scherrer’s formula, whose microstructure and the precursor were investigated by SEM. The findings showed that the higher calcination temperatures result in the larger average particle size. Ultrasonic velocity measurements in Cr2O3 nanoparticles suspended in PVA solution were made at different thermal conditions. In the sample Cr2O3+PVA the ultrasonic velocity increases up to 500C and then remains constant. The effort has been made to correlate the ultrasonic velocity/absorption behavior with the magnetic property.
Formation of Metastable Phases and their Stability in Mechanically Alloyed Ti-48Al-12Nb-1Cr (at %) System
Authors: Kumaran S. , Rao T. Srinivasa
Published: September 2009

The reported work is on Ti-48Al-12Nb-1Cr (at %) system synthesized in a high-energy planetary ball mill with optimized milling parameters. The synthesized powders are characterized by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), X-Ray Diffraction (XRD) and Differential Thermal Analysis (DTA) in order to understand the structural and phase transformation. The results obtained from the above said studies show the particles refinement, formation of non-equilibrium structures, etc. High-energy ball milling results super saturation of Al and Nb in titanium matrix at 15 hrs of milling, nanocrystalline nature at 20 hrs and amorphous phase formation at 50 hrs of milling. Differential Thermal Analysis (DTA) and XRD scans of MA powder thermally treated at 750°C for 1 hr show the formation of TiAl and TiAl3 intermetallic compounds.
Equal Channel Angular Pressing of Al Alloy AA2219
Authors: Anil Kumar V. , Karthikeyan M.K. , Gupta Rohit Kumar , Ramkumar P. , Sinha P.P.
Published: September 2009

Severe plastic deformation processes (SPD) are gaining importance as advanced materials processing techniques and hold immense potential in obtaining ultra fine-grained high strength materials. Among the SPD techniques, Equal channel angular pressing (ECAP) has its own merits to produce materials with ultra fine grains in bulk with better mechanical properties. The material deforms with high level of plastic strain inside the channel resulting in grain refinement of the output material with improvement in mechanical properties.
A very viable die configuration was conceptualized and die was made with 1200 channel angle. Processing of 25 mm dia. of Al alloy AA2219 at room temperature was successfully carried out and grain refinement was observed. The mechanism of grain refinement has been studied using optical and transmission electron microscopy (TEM). It was observed that low energy dislocation structure (LEDS) forms concurrently with sub-grain structure due to dislocation rearrangements, which provide stability to the evolving sub-grain structure. Dislocation mobility is hindered by the presence of precipitates and / or intermetallic dispersoids present in the matrix and results in presence of dislocations in grain interiors. The pile up of dislocations at intermetallic dispersoids was confirmed from the dark field TEM micrographs.
Present paper describes the experimental procedure and followed to attain severe plastic deformation through ECAP. Increase in hardness as well as refinement in the grain size after 5-passes have been discussed in light of extensive optical and TEM. The mechanisms of grain refinement to achieve nano-grained structure and strengthening accrued from the grain refinement through ECAP has been discussed.
Development of Nanomaterials from Natural Resources for Various Industrial Applications
Authors: Rajendran V.
Published: September 2009

In the present study, the synthesis of nano structured materials such as nano alumina (Al2O3), nano silica (SiO2), and nano hydroxyapatite (HAp) have been discussed for industrial applications. The oxide nano materials are prepared employing chemical methods from natural resources. The HAp is prepared employing sol-gel process using chemical precursors. The synthesised nano alumina (Al2O3) powder has been used to improve the physicochemical properties of refractories. The prepared nano particles employing different process techniques have been characterized using XRD, FTIR, EDAX and SEM studies. The silica nano particles have been coated on textiles to get the wrinkle free/antibacterial textile cloths/products. The synthesized nanoparticles from natural resources have been used in various industrial applications such as refractories, textiles and biomedical field.
Predicted Rake Face Wear of PCBN Cutting Tools in High-Speed Precision Hard Cutting
Authors: Wang Yu , Zhai Yuan Sheng , Yan Fu Gang , Liu Xian Li
Published: September 2009

PCBN cutting tool’s wear in high speed precision reaches tool wear criterion will cause cutting force and cutting temperature increase clearly, chip color change or melt. Even vibration in cutting will influence dimension accuracy and surface quality of workpiece. It is very useful to establish model by FEM simulation of tool wear predicted. The influence of tool wear in cutting conditions will assurance of machining quality and efficiency, decreasing rate of product cost. PCBN cutting tool’s wear is simulated by FEM software Deform 2D, rake face wear state can be analysed by the influence of tools geometric parameters and cutting parameters tool wear.