bluuebunny/crossref_metadata_2025 huggingface dataset:
MUSE Spectroscopic Identifications of Ultra-faint Emission Line Galaxies with MUV ∼ −15*
Authors: Maseda Michael V. , Bacon Roland , Franx Marijn , Brinchmann Jarle , Schaye Joop , Boogaard Leindert A. , Bouché Nicolas , Bouwens Rychard J. , Cantalupo Sebastiano , Contini Thierry , Hashimoto Takuya , Inami Hanae , Marino Raffaella A. , Muzahid Sowgat , Nanayakkara Themiya , Richard Johan , Schmidt Kasper B. , Verhamme Anne , Wisotzki Lutz
Published: September 2018

Using an ultra-deep blind survey with the MUSE integral field spectrograph on the European Southern Observatory Very Large Telescope, we obtain spectroscopic redshifts to a depth never before explored: galaxies with observed magnitudes m
AB ≳ 30–32. Specifically, we detect objects via Lyα emission at 2.9 < z < 6.7 without individual continuum counterparts in areas covered by the deepest optical/near-infrared imaging taken by the Hubble Space Telescope, the Hubble Ultra Deep Field. In total, we find 102 such objects in 9 square arcminutes at these redshifts. Detailed stacking analyses confirm the Lyα emission as well as the 1216 Å breaks and faint ultraviolet continua (M
UV ∼ −15). This makes them the faintest spectroscopically confirmed objects at these redshifts, similar to the sources believed to reionize the universe. A simple model for the expected fraction of detected/undetected Lyα emitters as a function of luminosity is consistent with these objects being the high-equivalent width tail of the normal Lyα-emitter population at these redshifts.
EU Permanent Structured Cooperation - a New Momentum for Streamlining Interaction Between the EU Operations Planning and Capability Development
Authors: Petráš Zdeněk , Spišák Ján
Published: September 2018

The authors' intention is to present findings to which they came while analysing the implementation process of the EU Permanent Structured Cooperation (PESCO), especially in the area of EU operations planning and development of capabilities required for achieving the EU level of ambition. Only issuing the EU Global Strategy in 2016 and its subsequent implementation process seems to be a momentum for specifying commitments stemming from PESCO. At present, there is a list of common binding commitments which 25 of 28 EU member states have signed to. This list includes specific commitments as for development of required capabilities needed for achieving expected objectives of CSDP operations. Nevertheless, a very critical point related to the current PESCO implementation process is whether the present level of EU member states integration allows fully completing all highly ambitious commitments as declared by political leaders.
Approaches to Scenario Development
Authors: Gireth Jan
Published: September 2018

The article deals with the issue of methodological approach to scenario development. This paper describes the methods and techniques used in scenarios development both in civilian sphere and within NATO and the EU, with an emphasis on their role in the military capability development process of the armed forces. The article defines the usual scenario construction process and describes the location and differences of generic and specific planning situations. In addition, the principles necessary to create quality scenarios are described here. The conclusion of the article deals with proposals focused on the elaboration of a methodology for scenario building in the Czech Armed Forces as part of the project "Strategic Alternatives to the Construction and Development of the Czech Armed Forces", which is being elaborated at the Center for Security and Military and Strategic Studies of the University of Defense in Brno.
Three Key Issues of Project Management in the Ministry of Defense Sector
Authors: Pitaš Jaromír , Mašlej Miroslav
Published: September 2018

Implementation of project management is a step by which the organization declares that it wants to offer unique products in the appropriate quality. Just as a newly implemented process to an organization is not always perfect and needs to be constantly improved. Consequently, the project management implemented in the organization needs to be improved. The article presents the main problems identified by the members of the project management courses, which took place at the University of Defense in Brno in period 2011 - 2018. The authors of the article, based on the analysis of the findings, concluded that problems identified in the Ministry of Defence of the Czech Republic are solvable and present possible approaches to the solution.
Démobiliser ? La reconversion de la défense aux États-Unis après la Guerre froide
Authors: J. Stricof Michael
Published: September 2018

Après la Guerre froide, les États-Unis devaient redéfinir le format de leurs forces armées en prenant en compte les retombées économiques attendues sous la forme de « dividendes de la paix », tout en évitant la réémergence d’une superpuissance et la menace des conflits régionaux. Des propositions pour la reconversion de l’industrie de la défense tentaient de réduire le budget et de transformer la politique étrangère américaine. Cependant, les impératifs politiques et la vision des responsables de la défense des administrations George HW Bush et Bill Clinton privilégièrent la continuité avec les structures de forces de la Guerre froide plutôt que des changements adaptés au « nouvel ordre mondial ».
Numérologie identitaire au sein de l’armée française renaissante en 1944-1945
Authors: Weiss Stéphane
Published: September 2018

En 1944, la libération de la majeure partie du territoire français a permis au général de Gaulle d’engager un vaste programme de réarmement, s’appuyant sur les Forces françaises de l’Intérieur. Quelque 150 régiments ont progressivement été recrées. Cet article explore la façon dont ces unités ont été nommées, entre filiation historique et choix politiques. En effet, sans attendre les décisions gouvernementales, d’assez nombreux responsables FFI ont octroyé de leur propre initiative des numéros de corps réguliers à leurs groupements, affirmant ainsi des revendications identitaires.
Façonner la mondialisation. Le pouvoir politique des multinationales
Authors: Chavagneux Christian , Achin Catherine , Yon Karel
Published: September 2018

Christian Chavagneux est économiste, éditorialiste à Alternatives Economiques . Spécialiste de la (dé)régulation des banques, de la finance 1 et de la mondialisation, il décrypte « l’économie politique des bulles » et les mécanismes qui favorisent les intérêts de la finance et des grandes firmes. Pour ouvrir ce numéro sur les tentatives de résistances syndicales au pouvoir des multinationales, il nous a semblé nécessaire de partir d’un tableau de l’état des forces en présence et de leur évolution. C’est ce panorama que cet entretien nous aide à dessiner.
La polarisation des élites administratives et économiques françaises et le conflit sur l’orientation stratégique du capitalisme français
Authors: Georgiou Christakis
Published: September 2018

Porter attention aux firmes multinationales permet d’appréhender la mondialisation de manière plus concrète, en soulignant le rôle que jouent les dirigeant.es des grandes entreprises dans les mutations du capitalisme. Si les multinationales ne sont pas apatrides, y a-t-il pour autant un intérêt commun aux multinationales françaises ? Ou bien un intérêt supérieur a-t-il émergé dans le cadre de l’intégration européenne pour unifier les classes possédantes à ce niveau ? En s’appuyant sur les outils de l’économie politique et de la sociologie des élites, Christakis Georgiou offre une réponse nuancée en montrant que le niveau national reste pertinent pour comprendre les conflits stratégiques qui traversent le patronat et se réfractent à une échelle régionale plus large.
Face aux multinationales : faire appliquer les normes et défaire les réputations
Authors: Achin Catherine , Bourdeau Vincent , Macé Arnaud
Published: September 2018

Alors que les multinationales s’organisent et trouvent des relais à l’échelle internationale auprès de grandes institutions – telles le FMI 1 ou l’OMC 2 – comment les mouvements sociaux, portés par les syndicats, les organisations non gouvernementales ou les associations citoyennes, peuvent-ils espérer corriger l’orientation de plus en plus libérale de l’économie mondiale ? Comment œuvrer à ce que de grands principes humanistes, à l’image de la soumission de l’économie au développement humain, pourtant mis en avant dès 1944 par la Déclaration de Philadelphie, puissent servir de boussoles aux décisions qui concernent la gouvernance de l’économie et de la finance internationales ? Mouvements a posé la question à deux figures du mouvement syndical et citoyen, Bernard Thibault, ancien secrétaire général de la CGT, aujourd’hui membre du Bureau permanent de l’OIT 3 , et Annick Coupé, secrétaire générale d’ATTAC après avoir été porte-parole de l’Union syndicale Solidaires, ainsi qu’à une spécialiste du droit du travail international, Michèle Bonnechère, professeure émérite de l’Université d’Évry.
Syndicats et entreprises multinationales, passé, présent, futur
Authors: Pernot Jean-Marie
Published: September 2018

La mobilisation syndicale contre les stratégies des multinationales a une longue histoire, dont Jean-Marie Pernot nous rappelle ici les étapes. Dans le contexte de la guerre froide et de l’affrontement des Confédérations syndicales internationales, l’action revendicative a d’abord surtout été portée par les secrétariats professionnels internationaux organisés par branche d’activité. Dans les années 1990, elle s’est ensuite concentrée sur la critique des codes de bonne conduite au sein des multinationales, dénoncés comme instruments de communication non contraignants. C’est depuis les années 2000, autour de la négociation d’accords-cadres internationaux et des comités d’entreprise européens, que s’articule la résistance interne aux multinationales, appuyée sur des coalitions de syndicats internationaux et d’ONG.
Les Comités d’entreprise européens : un outil d’action transnationale
Authors: Warneck Fabrice
Published: September 2018

Créés en 1994 par une directive européenne, les Comités d’Entreprise Européens (CEE) promettaient une coordination de l’action syndicale à l’échelle d’un continent. Malgré un rôle consultatif limité – tant sur les projets économiques que sociaux des entreprises – les CEE rendent possible la rencontre et l’échange entre travailleur.ses européen.nes. Les politiques d’austérité qui ont gagné la plupart des pays d’Europe n’incitent malheureusement pas à valoriser le rôle des syndicats et ne contribuent pas à sécuriser leur rôle dans l’entreprise. Devant les obstacles que rencontre souvent la mise en œuvre des CEE, l’heure est aujourd’hui, pour les syndicats, à la tentation du repli national. Cet article se propose de faire le bilan de cet outil plein de promesses, qui suscite aujourd’hui un certain désenchantement, en pointant notamment les évolutions législatives européennes, mais aussi françaises, récentes qui donnent quelques raisons de rester optimistes.
« Nous n’avons plus peur » : la mobilisation inattendue des travailleur.ses de Ryanair
Authors: Anderson Jeremy
Published: September 2018

Le succès de la compagnie aérienne Ryanair repose notamment sur son modèle économique fondé sur les bas salaires. Pour le préserver, elle n’a pas hésité à faire la guerre aux syndicats, à choisir les pays aux législations les plus accommodantes pour ses pratiques managériales agressives. Cependant, depuis 2017, la multinationale a été contrainte de reconnaître les syndicats, d’écouter et de négocier avec ses salarié.es. Cet article retrace les conditions et les actions qui ont permis cette victoire syndicale.
Livreur.ses de tous les pays, unissons-nous !
Authors: Bouvier Steven
Published: September 2018

L’ubérisation, stade suprême du capitalisme ? Depuis quelques années, les plateformes numériques réorganisent et transforment le travail, permettent à leurs propriétaires de maximiser leurs profits et de diviser les travailleur.ses. Ces dernier.es paient le prix fort : mal rémunéré.es, payé.es à la tâche, condamné.es à la précarité. Malgré ces obstacles, les forçats de la pédale s’organisent et mènent des luttes. Dans cet article, un membre du Collectif des Livreurs Autonomes de Paris (CLAP) nous raconte les mobilisations en cours face à Deliveroo. Au niveau local, national et transnational, les livreur.ses s’organisent, font alliance avec les syndicats et font pression sur la multinationale. Ils et elles inventent des solutions qui permettront à l’avenir de créer une économie au service de celles et ceux qui la font tourner.
Du salarié détaché au salarié exploité : la lutte syndicale européenne dans le secteur de la construction
Authors: Mesure Marina
Published: September 2018

En France et en Europe, le nombre de travailleur.ses détaché.es explose. C’est souvent un moyen pour les entreprises de faire du dumping social. Et cela se concrétise par de mauvaises conditions de travail pour les salarié.es, par des vols de salaires et de droits sociaux. Face à ces abus, depuis quelques années la solidarité s’organise. La CGT Construction a notamment mis en place, avec d’autres syndicats européens, un réseau pour venir en aide aux travailleur.ses détaché.es. Une expérience qui ouvre la voie à une continuité syndicale européenne pour les travailleurs et les travailleuses détaché.es.
La mondialisation à domicile : la lutte des coiffeuses du 57, boulevard de Strasbourg
Authors: Brasier Pierre-Jean , Cottin-Marx Simon
Published: September 2018

Membre de l’Union Départementale CGT de Paris, Marilyne Poulain milite depuis une dizaine d’années pour et avec les travailleur.ses sans-papiers. Dans cet entretien, à travers son parcours, elle nous raconte l’histoire récente des luttes des travailleur.ses migrant.es et celle des coiffeuses du 57, boulevard de Strasbourg, dont les patrons ont été condamnés à de la prison ferme pour « traite des êtres humains ».
Nucléaire, une (dé)raison d’État
Authors: Binctin Barnabé , Cottin-Marx Simon
Published: September 2018

Depuis une cinquantaine d’années, Bernard Laponche nous alerte sur les dangers de l’atome. Dans cet itinéraire, ce physicien nucléaire qui fut membre du Commissariat à l’Énergie Atomique (CEA), nous raconte comment son expérience syndicale l’a amené à découvrir le risque nucléaire, pour les travailleurs de cette industrie et plus largement pour la population. A travers son parcours militant et professionnel passant par la CFDT, Global Chance, ou le cabinet du ministère de l’Environnement, il nous révèle la folie d’un État français enferré dans une politique pronucléaire. Cet ancien directeur de l’AFME (l’ancêtre de l’Agence de l’environnement et de la maîtrise de l’énergie – ADEME) a aussi imaginé et construit des alternatives : il est un infatigable défenseur des économies d’énergie et des énergies renouvelables.
In the Crosshairs: Examining Firearms, Violence, and Mental Illness
Authors: Anacker Lisa , Pinals Debra A.
Published: September 2018

The general public often looks to mental health professionals to predict or somehow stop acts of gun violence, especially after highly publicized mass shootings. What is often less sought by the public, but no less critical, is the role of mental health professionals in examining risk of suicide related to firearms. Therefore, it is important for mental health professionals to understand the current data about firearms as they relate to violence against others, suicide, and mental illness, as well as the associated clinical implications. Understanding the general public's conceptions related to gun violence and mental illness, as well as the background and current developments of these important issues, will aid the mental health professional on legal and clinical matters, including variations of legislation related to guns and mental illness, gun violence–restraining orders, firearm-related clinical conversations, and risk assessments.

[
Psychiatr Ann.
2018;48(9):416–420.]
Le site archéologique médiéval et moderne de Terravecchia (Sicile, Italie)
Authors: Racinet Philippe , Woimant George-Pierre
Published: September 2018

Les recherches archéologiques et historiques menées sur un bourg sicilien mentionné dès le xiie siècle et abandonné à la suite du tremblement de terre de 1693 ont consisté en une prospection de surface associée au relevé topographique complet du site. Elles ont permis d’identifier une implantation dense sur un relief accidenté, organisée autour de certains pôles comme le château ou les églises. Le relevé, complété par des nettoyages de surface ciblés, constitue un document fiable pour les recherches archéologiques. Ces dernières ont été engagées sous la forme de sondages ponctuels, pour éclairer les origines de la ville et sa structuration à l’époque moderne. Des aménagements programmés et systématiques semblent avoir eu lieu à la fin du Moyen Âge, ils ont impliqué des nivellements et des reconstructions d’envergure certainement suivis d’une forte urbanisation, non ou mal contrôlée.
Les coupes en verre à décor chrétien découvertes en Belgique (fin ve-début vie siècle)
Authors: Van Wersch Line , Van Geesbergen Dominique , Vrielynck Olivier
Published: September 2018

Les coupes à décor chrétien sont de petits vases en verre soufflé-moulé qui présentent sur leur fond un décor imprimé composé de motifs chrétiens. Plusieurs d’entre elles ont été découvertes dans des contextes mérovingiens sur le territoire de la Belgique actuelle. Dans cet article, un nouvel inventaire des objets a été dressé. Une approche contextuelle attentive a permis de les dater avec plus de précision et d’en étudier la répartition. Les techniques et matériaux utilisés pour leur fabrication ont été mieux compris grâce à des analyses chimiques. Enfin, l’étude iconographique s’est enrichie de nouveaux relevés graphiques et photographiques. Au terme de ce travail, il s’avère que ces coupes sont d’excellents témoins pour aborder certains aspects de la culture, de la société et de l’économie mérovingiennes en Belgique.
 Experiência da família de crianças e adolescentes com estomas gastrointestinais/ The family’s experience of children and adolescents with gastrointestinal stomas
Authors: Zacarin Clara Ferraz Lazarini , Borges Amanda Aparecida , Dupas Giselle
Published: September 2018

Cuidar de uma criança estomizada provoca impactos na família e gera grande demanda de cuidados permanentes e específicos. Esse estudo teve como objetivo compreender a experiência da família de crianças e adolescentes que têm estomias gastrointestinais. Trata-se de estudo qualitativo, em que se utilizou o Interacionismo Simbólico como referencial teórico e a análise de narrativa como método, a fim de apreender a experiência da família. A análise dos dados aponta que as famílias passam por processo dinâmico frente a indicação da necessidade da realização do estoma. A aceitação da condição que no filho é progressiva e, mesmo diante das dificuldades, os familiares apontam otimismo e almejam reinserção deste filho na sociedade, preferencialmente sem dispositivo. Os resultados deste estudo possibilitam aprofundar o conhecimento acerca da experiência da família neste contexto, e isso permite melhorar o atendimento de saúde, avançando nas questões da assistência de enfermagem. Neste contexto, o estudo destaca a necessidade de apoio de uma rede estruturada para a família para acompanhar, orientar e sanar dúvidas existentes do processo de colocação e cuidado ao estoma.
O GRUPO DE OUVIDORES DE VOZES: DISPOSITIVO DE CUIDADO EM SAÚDE MENTAL
Authors: Fernandes Henrique Campagnollo Dávila , Zanello Valeska
Published: September 2018

A alucinação auditiva é um fenômeno que participa da vida de muitas pessoas que fazem tratamento no sistema público de saúde mental de nosso país. No cotidiano de um Centro de Atenção Psicossocial de uma capital brasileira, ouvidores de vozes relatavam com frequência que continuavam sofrendo em função de experiências alucinatórias, mesmo seguindo o tratamento prescrito pela equipe de saúde. Considerando esse problema, foi criado no local um grupo voltado para a lida com o fenômeno. Este artigo teve como objetivo analisar experiências desse grupo. Para isso, utilizou-se o método qualitativo, o qual envolveu o registro de 62 sessões sob a forma de diário de campo, e a análise do corpus. A organização dos dados se deu em três espectros temporais estruturantes de (psico)terapias de grupo em geral: “apresentação”, “trocas de experiências”, e “fechamento”; além de um aspecto dinâmico, denominado de “manejo terapêutico”. A apresentação promoveu a ambientação dos participantes e possibilitou o surgimento de temas importantes, os quais foram trabalhados no decorrer da sessão. Ao trocarem experiências, os integrantes conseguiram compreender algumas dinâmicas relativas às vozes, e houve a promoção de determinados fatores terapêuticos. O manejo serviu para alinhavar os espectros temporais e garantir a fluidez da atividade. Recomenda-se a adoção de grupos com esse foco e formato nos serviços de saúde mental, considerando que eles ampliam a capacidade de cuidado.
Potential of the Biosorbent from Waste for the Separation of Cu(II) from Aqueous Solutions
Authors: Rozumová Lucia , Legátová Barbora , Prehradná Jana
Published: September 2018

The aim of this paper was to study of biosorption by use waste material as a biosorbent. Waste material used in this work was activated industrial hemp shives (Cannabis sativa), which occurs during the processing of hemp shives grown as the waste biomass in the processing process. The sorbent was utilized to reduce the content of Cu(II) ions from aqueous solutions. Sorption experiments of the cannabis hemp shives were conducted in a batch mode by use the model solutions of Cu(II). The impact of pH, contact time and initial concentration on the pollutant removal efficiency was observed. The sorption kinetics were evaluated with pseudo-first and pseudo-second order kinetic models. Adsorption process has been modeled by the Langmuir, Freundlich, Temkin and Dubinin‑Radushkevich isotherms using linear regression. The results of this study indicated that the application of hemp shives of Cannabis sativa waste material as a biosorbent is highly effective for the removal copper ions from wastewater.
A Three-Dimensional Metal-Organic Framework Displaying Guest-Dependent Spin-Crossover Behaviour
Authors: Shao Feng , Zhuang Jia Jia , Luo Gang , Zhang Ke , Li Chang Jiang , Zhu Hai Feng , Tong Jia Ping
Published: September 2018

A new three-dimensional metal-organic complex, [{Fe (NCSe)2}3(TPB)4]x(guest), was prepared with the ligand of TPB (1,3,5-tris (4-pyridyl) benzene). The X-ray single crystal diffraction studied in 100 K and 173 K shown the change of bonds and angles of the framework. The guest exchange and magnetic properties indicated that the 3D framework can be responsible to the solvent guest molecules and shows guest-dependent spin-crossover behaviour.
Grafting Carbon Nanotube for Dye-Sensitized Solar Cell Improvement
Authors: Yooruengdech Nongnapas , Ontong Suthisa , Pongprayoon Thirawudh
Published: September 2018

Carbon nanotubes (CNTs) were modified by grafting polymerization with copolymer of polyaniline and poly (vinyl acetate) for improving their electrical conductivity and water dispersion. After surface modification of CNTs, they were used to fabricate as the photoelectrode or working electrode for the dye-sensitized solar cell (DSSC). The characterizations of the modified CNTs were done by FTIR, TEM and SEM. Lastly, the efficiency of DSSC prepared from the modified CNT was evaluated by photovoltaic test. The results showed the high performance of the grafting CNTs-added working electrode.
Fabrication of Zinc Oxide-Polyaniline Composite on Kapok Paper for Methylene Blue Dye Removal in Aqueous Solution
Authors: Lacuesta Aldwin Christian , Balela Mary Donnabelle , Herrera Marvin U.
Published: September 2018

Polyaniline-zinc oxide composite on Kapok paper were fabricated for methylene blue dye removal in aqueous solution. Kapok fibers were fabricated into papers. The fabricate paper served as substrate for the zinc oxide-polyaniline composite. Zinc oxide particles were deposited on the Kapok paper using an in-situ method while polyaniline molecules are deposited on paper using Successive Ionic Layer Adsorption and Reaction (SILAR) method. The polyaniline molecules were deprotonated using sodium hydroxide (NaOH) to be able adsorb cationic dyes in aqueous solution. The samples were characterized using scanning electron microscope (SEM), energy dispersive X-ray (EDX) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. Results show that the deprotonated polyaniline nanocomposite was able to remove at about 75% more dye compared to the as-synthesized polyaniline nanocomposite.
Secondary Machining Characteristics of Additive Manufactured Titanium Alloy Ti-6Al-4V
Authors: Polishetty Ashwin , Raju Basil , Littlefair Guy
Published: September 2018

Titanium alloy, Ti-6Al-4V is a popular alloy used in wide range of design applications mostly in aerospace and biomedical industry due to its advantageous material properties. This research is based on threading operation in a cylindrical workpiece of Ti-6Al-4V additive manufactured by Selective Laser Melting (SLM) technique. Secondary machining is described as the operations that are performed on the workpiece after a primary machining in order to achieve a required finish and form. Common secondary operations after drilling includes threading, reaming and knurling. Threading is a significant machining process in almost all applications of Titanium alloys. The development of an efficient threading process for Titanium alloys and enhancing existing methods may lead to a wider application of additive manufactured Titanium alloys. The aim of this research is to find out favorable threading conditions for Titanium alloy Ti-6Al-4V to obtain better machinability. Threads are tapped into the workpiece using variable machining parameters such as spindle speed and depth of cut. Statistical data are collected and analyzed by qualitative and quantitative evaluation of the threads. The outputs under consideration to evaluate efficiency of the secondary machining include surface texture (roughness (Ra)), dimensional accuracy (thread geometry) and power required (cutting force).
Effects of Cutting Speed and Feed Rate on Surface Roughness in Hard Turning of AISI 4140 with Mixed Ceramic Cutting Tool
Authors: Paengchit Phacharadit , Saikaew Charnnarong
Published: September 2018

This work investigated the influences of cutting speed and feed rate on surface roughness in hard turning of AISI 4140 chromium molybdenum steel bar using mixed ceramic inserts Al2O3+TiC under dry condition for automotive industry applications. Turning experiments were conducted by varying cutting speed ranging from 150 to 220 m/min and feed rate ranging from 0.06 to 1 mm/rev. General factorial design was used to analyze the data set of surface roughness and determine statistically significant process factors based on analysis of variance results. The results showed that average surface roughness was significantly affected by feed rate and interaction between cutting speed and feed rate at the level of significance of 0.05. An optimal operating condition for hard turning of AISI 4140 with the ceramic cutting tool that produced a minimum machined surface roughness was obtained at cutting speed of 220 m/min and 0.06 mm/rev.
Rheological Behavior of Mixture of Carbonyl Iron Powder (CIP) and High Density Polyethylene (HDPE)
Authors: Doifode Devanand S. , Deorukhkar Bharat D. , Date Prashant P. , Alexandrov Sergei
Published: September 2018

Rheological study has been performed experimentally by using melt flow index (MFI) tester on a mixture of CI (Carbonyl Iron) powder and HDPE (High-Density Polyethylene) polymer. The rheological properties such as volume flow rate (cm3/s), shear strain rate (s-1) and viscosity (Pa.s) are investigated for varying conditions of temperature and weight (pressure). This also includes experimental determination of viscosity dependence over parameters like temperature, shear strain rate and CI powder loading by weight added in HDPE. For this experimental conditions selected are temperatures 4480K-5230K in steps of 250K, weights in MFI tester (ultimately converted to shear strain rate) 0.325, 1.20, 2.16, 3.80, 5.00Kg and carbonyl iron powder loading in binder HDPE (by weight) 80%-92% in steps of 6%. A constitutive equation for viscosity is formulated which considers all factors affecting viscosity with the maximum percentage error of about 4% between experimental value and value predicted by the formulated equation is obtained.
Viscoelasticity of Chemically Bonded Interfacial Epoxy-Polyurea Matrix per Migration of Epoxy Species via Curing Time Parameter
Authors: He Li , Attard Thomas L.
Published: September 2018

A new fiber (x) reinforced Dynamic Covalent epoxy-polyurea Interface (x-DCEPI) shows good mechanical energy transferability of impact and vibration forces. The bonding property of x-DCEPI interface, engendered between curing, or reactive, epoxy and dynamic polyurea, is controlled by epoxy curing time (tc). The reaction of curing epoxy, where tc is a thermodynamic processing parameter, and fast-curing/ dynamic aliphatic polyurea, which lacks polyol in its resin chain extender, is linked to bulk mechanical energy transfer, quantified specifically via the loss modulus of x-DCEPI. The parameter tc effectuates designable chemical bond properties within x-DCEPI. Using Generalized Maxwell models, viscoelastic properties of epoxy, polyurea, and x-DCEPI are predicted, and results are verified using Dynamic Mechanical Analysis (DMA). The Maxwell models for x-DCEPI, as a function of tc, are used in a finite element analysis (ABAQUS) to control performance of dynamically loaded structures.
Beneficiation of Sugarcane Bagasse Boiler Ash via Production of Syntactic Foams and Thermal Refractory Materials
Authors: Lokhat David , Sewlala Irshaan , Hooblal Diajal , Paul Bradley
Published: September 2018

Aqueous solutions of sodium polytungstate were used to fractionate samples of sugarcane bagasse ash by heavy media separation. Practically no cenospheres were recovered from the ash samples. The method was successful in separating fibrous carbonaceous particles with a uniform surface from particles containing more silica and having a less uniform surface. A geopolymer refractory brick having satisfactory durability was produced from sugarcane bagasse ash with metakaolin and ball clay fillers and a sodium metasilicate/hydroxide activator liquor. Drying and firing shrinkage, bulk density and ultimate compressive strength tests were performed to determine the most feasible combination of ingredients. Geopolymer samples produced using aluminium powder instead of ball clay were found to be very brittle and unsuitable for refractory service.
Photonic Properties of PZT Powders along the Crystallization Process of the Polymeric Precursor
Authors: da Silva Margarete Soares , de Souza Eliane F. , Ramos Talita Cuenca Pina Moreira , Barbosa Graciele Vieira , Fischer Eliane Kujat , da Silva Lucas L. , Li Máximo Siu , de Moura Ana Paula , Cavalheiro Alberto Adriano
Published: September 2018

Lead zirconate titanate (PZT) is a wide versatile material applied in several electronic devices. Some of dielectric and piezoelectric characteristics depend on phase formation, crystallization and composition. In this work, we prepare PZT powder samples with different compositions by the Polymeric Precursor Method, which were thermally treated at very low temperatures in order to get amorphised powder samples. The zirconium-rich PZT6040 sample showed a significant uptake in photoluminescent emission between 320 oC and 350 oC, followed by a slightly increasing in bandgap energy. In spite of the bandgap energy posses the typical value for several structurally disordered semiconductors, these effects were associated to the coexistence of pyrochlore and tetragonal perovskite phases in that referred conditions.
Effect of the Addition of the Waste Generated from the Feldspar Mining on the Obtainment of Ceramic Brick
Authors: Sartor Felipe de Luca , Spricigo Luís Philipe , Niero Danila Ferreira , Bernardin Adriano Michael , Montedo Oscar Rubem Klegues , Angioletto Elidio
Published: September 2018

TheNossa Senhora do Carmomining company, located at the southern of Santa Catarina (SC), Brazil, explores a large amount of feldspar to the ceramic market. As a result, waste is inevitable in the production and processing of the feldspar mineral, which results in an environmental impact. Therefore, this study aims to evaluate the effect of the addition of the waste coming from the feldspar mining in the composition of ceramic bricks. In this way, the waste and a clay mineral were characterized. The waste (0, 5, 15 and 25 wt%) was added to a composition of clay brick based on a standard clay fromMorro da Fumaça, Santa Catarina, Brazil. Specimens were extruded and sintered at temperatures of 1123, 1223, and 1323 K. The technological properties assessed in this study were linear shrinkage, water absorption and bending strength. The data were assessed by analysis of variance. The results showed the feasibility of adding 15 and 25 wt% of waste to the brick composition. All technological properties were improved when compared to pure samples, except for linear shrinkage. The analysis of variance showed significant and reproducible effects for the water absorption results. The results for linear shrinkage and bending strength showed no statistical significance.
Absorption Evaluation of Water in Panels from Elephant Grass with Eucalyptus sp. Leaves
Authors: de Souza João Sammy Nery , Osajima Josy Anteveli , Furtini Marcelo Barbosa , da Silva Filho Edson Cavalcanti , Abreu Yara Karolynne Lopes , Ribeiro M.X. , de Araújo Francisca Pereira , Santana J.S. , Melo D.F.
Published: September 2018

There are reports that the production of panels with various mixtures is quite feasible. However, the knownlogment of production of panels with other residues is litle, except wood. The objective of this work was to evaluate the effect of water absorption on panels produced with elephant grass (Pennisetum purpureumSchum.) andEucalyptussp. leaves, Consolidated with urea-formaldehyde adhesive. For the production of the panels, the elephant grass (CA) was used, without particle size reduction, andEucalyptussp. (EU), freshly collected and crushed as powder. Two panels were produced, one consisting of 100% elephant grass (CA) and another in the proportion (1: 1, from CA: EU), with urea-formaldehyde adhesive. From each panel, 4 specimens were removed and the water absorption test was carried out for 2 hours, in addition to the determination of the apparent density. Panel test specimens (CA) showed, on average, an initial apparent density of 0.5953 g.cm-3and final (water absorption) of 0.5465 g.cm-3, while those of CA + EU showed an apparent density of 0.5478 g.cm-3and 0.6881 g.cm-3. The panels (CA) and (CA + EU) produced showed good consolidation after pressing, but It was verified that there are possibilities of improvement in order to minimize water absorption and improve the stability of this product.
Addition of Zinc Oxide Nanoparticles in Biodegradable Polymer and Evaluation of its Antimicrobial Activity
Authors: Capelezzo Ana Paula , Mohr Laura Cassol , Godoy Janayne Sander , Bellei Alessandra Sgnaulin , Silva Luciano Luiz , Martins Maria Ana Pignatel Marcon , Fiori Márcio Antônio , Mello Josiane Maria Muneron
Published: September 2018

The food contamination for pathogenic microorganisms is a serious problem for the food security. Many actions can be taken in order to reduce this pathogenic multiplication, highlighting the use of active packaging for the food conservation, which have antimicrobial agents dispersed in its surface. The metal oxides and its nanoparticles have been shown effective additives for this purpose. With the growing concern with the environmental and the use of less aggressive materials, biodegradable polymers emerge like a good alternative. This work has the goal to investigate the effect on antimicrobial activity against Gram negative (Escherichia coli) and Gram positive (Staphylococcus aureus) bacteria when added zinc oxide nanoparticles (ZnO NPs) in concentration of 1% (wt/wt) in the biodegrable polymer Ecoflex®. The system was homogenized and proccessed in industrial extruder single screw and the polymer’s antimicrobial activity was evaluated by the agar diffusion tests and counting surviving microorganisms with the time. The results showed that the biodegradable polymer Ecoflex®with ZnO NPs exhibit good antibacterial activity.
Factorial Experimental Planning Applied for Evaluated Effect of Matrix Temperature and Screw Rotation Speed of Extrusion in Mechanical Properties and Dimensional Changes in PVC Pipes
Authors: Fiori Júnior J. , Piletti Raquel , Ilha J. , Pierini M. , Riella Humberto Gracher , Fiori Márcio Antônio
Published: September 2018

This study evaluated the effects of temperature and speed screw rotation of rigid recycled PVC pipe extrusion process on mechanical properties and dimensional variation. In developing the experiments were used the factorial design method type 2k. Were studied the influence of process variables on the properties of impact resistance, dimensional change and tensile strength of PVC pipe. From this study, it was possible to define the best extrusion process conditions with a point of view on the best properties of PVC pipes. The results indicated that the screw rotation has a significant influence on the impact property. For the dimensional variation, the extrusion temperature had a significant influence. There is no significant statistical values for the tensile strength in the studied variables.
Micromechanical Modeling of Dual-Phase DP600 Steel Sheet Plastic Behavior Based on a Representative Volume Element Defined from the Real Microstructure
Authors: Barbosa Gustavo Coqui , Moreira Luciano Pessanha , da Silveira Lílian Barros , da Silva Fabiane Roberta Freitas , Cardoso Marcelo Costa
Published: September 2018

Dual-phase steels offer very attractive combinations of strength and ductility owing to the coexistence of different microstructures components and their interactions. These steels are suitable to the automotive industry due to their improved impact resistance increasing the passenger safety along with the vehicle weight reduction. The properties of the dual-phase steels are attributed to the chemical composition, type, size, amount and spatial distribution of different phases that can be obtained during thermomechanical treatments, namely, ferrite and martensite. In this work, the microstructure of as-received DP600 cold rolled steel sheet with 1.2 mm nominal thickness was firstly characterized by means of scanning electron microscopy technique. Then, a representative volume element was obtained from the DP600 microstructure and a micromechanical finite element model is proposed considering the steel chemical composition, average ferrite grain size, martensite volume fraction and mechanical properties of both ferrite and martensite phases. The uniaxial tension loading was simulated by assuming either plane-stress and plane-strain conditions. The numerical predictions corresponding to the plane-strain model are in good agreement with the experimental true stress-strain curve determined along the sheet rolling direction. The proposed finite element micromechanical approach based on the real microstructure proved to be an important tool to evaluate both local and overall behaviors of DP600 steel grade.
Effects of Heat Input Conditions on the Local Thermophysical Properties of Super Duplex Stainless Steels
Authors: de Castro José Adilson , da Fonseca Gláucio Soares , Almeida D.S.S. , Lopes L.C.R. , Xavier C.R. , de Oliveira Elizabeth Mendes
Published: September 2018

The thermal properties of the super duplex stainless steels are strongly affected by the thermal history when welding procedure are applied leading to substantial changes on the mechanical properties of the welding region. The controlled dual phase microstructure (ferrite and austenite) guarantee excellent mechanical properties such as mechanical strength and corrosion resistance, in addition to small thermal expansion coefficient and high thermal conductivity. In this research a model able to predict the thermal history of the welding pieces coupled with local mechanical properties developed during welding procedure is developed. The model was verified by measured temperature profile and used to predict local properties such as grain size evolution, hardness and mechanical strength. An inverse method was implemented to obtain the parameters fitting for the grain growth evolution, hardness and yielding strength compatible with the final microstructure and grain size measured using SEM images and stereological techniques.
Study of Wear on Nicraly Coating Sprayed by HVOF on 316 Steel and Laser CO2 Remelting Process
Authors: Silva Silvelene Alessandra , Oliveira Ana Claudia Costa , Pita Glaucia Regina , Ferreira Maria Fernanda Souza , de Vasconcelos Getúlio
Published: September 2018

The use of NiCrAlY is a great alternative as Bond Coat - BC (bonding layer) in coatings for turbine vane, and it is possible to increase its life. This work aims to study the BC layer of NiCrAlY on the substrate of 316 steel which was deposited by the High Velocity Oxygen Fuel method (HVOF) and after laser remelting irradiated.selective laser melting which is an innovative process. The laser treatment induced changes in porosity, microhardness and wear resistance. After spraying, the samples were irradiated with a CO2laser beam by varying the scan speed in 50, 100 e 200 mm/s. The speed at which the metallurgical bond between the coating and the substrate occurred was of 50 mm/s. A wear test was performed to analyze the thickness of the coating, which was 60 μm, and the hardness profile and hardness profile where it presented a higher hardness in the coating after the laser treatment. The investigations range included analysis of top surface of coatings by XRD characterization oxides formed types and microscopic investigations of coatings morphology.
Effect of Cooling Rate on the Transformation Temperatures of Ni50Ti36Hf14 Melt-Spun Ribbons
Authors: Soares R.L. , Castro Walman Benicio
Published: September 2018

Solidification structures and shape memory characteristics of Ni50Ti36Hf14(at.%) alloy ribbons prepared by melt spinning were investigated by means of differential scanning calorimetry and X-ray diffraction. In these experiments particular attention has been paid to change the velocity of cooling wheel from 20 to 40 m/s. Then the cooling rates of ribbons were controlled. The effect of this cooling rate on solidification structures and martensitic transformation behaviors is discussed. When the ribbon is produced at a wheel velocity of 40 m/s in melt spinning, the degree of supercooling becomes high because of its thinner thickness.
Analysis of Mechanical and Micro-Structural Properties of Shaft Tips Manufactured in ABNT 1045 Steel Applied in Transportation Ore Fractured Early
Authors: Magalhães Narubia Miranda , da Silva Lourival Augusto Júnior , da Silva Oliveira Gustavo Antônio , Brandão Sérgio Mateus , Wobeto Ricardo , Monteiro Aline Alcamin , Silva Josemar Gomes
Published: September 2018

This paper aims is the study of shaft tips applied in ore transportation that are subjected to continuous torsional stresses, and which rupture early. This component consists of an ABNT 1045 steel shaft, where an ABNT 1020 steel flange is welded by the MIG/MAG (GMAW) process, both fixed, in addition to welding, by ABNT 1020 steel latches welded to the flange and shaft. The methodology is based on fracture analysis of the material and application of thermal treatments at different temperatures in order to reduce the incidence of early fracture. The results showed that the thermal treatment at 300oC for 4 hours was the most efficient in all regions, giving the shaft an increase of tenacity, without losing its mechanical resistance and hardness, indispensable properties to the shafts taking into account its characteristics operation.
Observations on Dynamic Strain Aging Manifestation in Inconel 718 Superalloy
Authors: Rezende Monica Costa , Araújo Leonardo Sales , Gabriel Sinara Borborema , Dille Jean , de Almeida Luiz Henrique
Published: September 2018

The manifestation of dynamic strain aging (DSA) in Inconel 718 is reported in this work. Analysis were performed in the material with different microstructures resulting from solution anneal and aging treatment. Tensile tests were made under secondary vacuum with temperature ranging between 200 and 950°C and strain rates of 3.2 x 10-3 to 3.2 x 10-5 s-1. Results showed the range of DSA occurrence. Analysis indicates that at lower temperatures, from approximately 200 to 450°C, serrations are controlled by the diffusion of carbon. At higher temperatures, until 800°C, DSA coincided with the occurrence of other thermally activated phenomena: dynamic precipitation, especially γ’’, and Oxidation Assisted Intergranular Cracking (OAIC). It was observed that competitive phenomena affect DSA manifestation directly due to the availability of niobium in solid solution.
Analysis of the Effect of Cyclic Fatigue on the Flexural Strength of a Ceramoceramic System Used in Dental Prostheses
Authors: de Carvalho Cristiane Fonseca , de Melo-Silva Cláudio Luis , de Melo-Silva Tereza Cristina Favieri , de Araújo Fábio Amaral , Lins Jefferson Fabricio Cardoso
Published: September 2018

The aim of this study was to analyze the flexural strength of ceramics based on yttria-stabilized zirconia (YTZP) , used in the manufacture of dental prostheses infrastructure before and after aging with cyclic fatigue in moisture. The samples were made by pre-sintered blocks of ZirkonTransluzent (Zirkonzahn GMHB) from YTZP ceramics with and without feldspathic ceramic coating, divided into groups: G1 = YTZP control; G2 = YTZP aged; G3 = YTZP + feldspathic; G4 = YTZP + aged feldspathic. The samples were submitted to a three-point bending test with a speed of 0.5 mm / min. The mean values of the flexural strength values were G1 = 645 MPa (DP ± 124), G2 = 681 MPa (DP ± 129), G3 = 904Mpa (DP ± 157) and G4 = 954Mpa (DP ± 243). The values of groups G1 and G2; G3 and G4 were statistically similar, depending on the presence or absence of coating. Cyclic stresses did not affect the flexural strength of the material
Behavior of Polypyrrole Film Chemically Polymerized with Lauric Acid on Copper Surface
Authors: Ferreira Bárbara Ramos , Liu Andrea Santos , Cho Liu Yao
Published: September 2018

Pyrrole was successfully polymerized on copper surface in ethanol solution using hydrogen peroxide as catalyst to generate an adherent and homogeneous polypyrrole (PPy) coating. The PPy was formed of clusters composed of small spherical grains. The layer has remained stable when immersed in 0.1mol L-1NaCl for 7 days, which indicated that the copper-PPy arrangement is stable in corrosive environment. The polarisation curves showed that the PPy layer can promote a positive displacement in the corrosion potential compared to the value of the uncoated copper. It also was observed that the corrosion current density decreases sharply in the presence of the lauric acid as dopant. These results indicate that PPy-lauric acid can act as a protective layer on copper and improve the overall corrosion performance.