bluuebunny/crossref_metadata_2025 huggingface dataset:
L’ampleur du désastre : l’évaluation américaine d’un conflit nucléaire avec l’URSS (1953-1965)
Authors: Baulon Jean-Philippe
Published: September 2018

La Maison Blanche crée en 1953 un sous-comité du Conseil de Sécurité nationale dont la mission est d’évaluer les dégâts que causerait une guerre nucléaire. Ce groupe travaille dans le plus grand secret durant les présidences Eisenhower et Kennedy avant d’être dissous par Johnson en 1965. La déclassification récente d’une partie de ses études révèle la constitution d’une véritable expertise du désastre. Refusant la simple intuition, le sous-comité produit des analyses selon des méthodes revêtant une forme scientifique. Il détermine ainsi les conséquences probables d’un conflit dans tous les aspects de la vie nationale. Ses conclusions, de plus en plus pessimistes, sont présentées chaque année au Président et contribuent ainsi à l’enracinement de la dissuasion.
Le renseignement politique en Indochine à l’épreuve de la vietnamisation de la Sûreté (1949-1955)
Authors: Le Page Jean-Marc
Published: September 2018

Le contrôle de la police est un élément fondamental de souveraineté pour un Etat. Durant la guerre d’Indochine, son transfert au jeune Etat vietnamien est un facteur de légitimité, d’autant plus pour un service qui a symbolisé la puissance coloniale. Durant six années la vie de la sûreté vietnamienne sera un révélateur des difficultés de l’Etat dirigé par Bao Dai à se construire. Après s’être constituée, la sûreté nationale est confrontée aux pouvoirs des gouverneurs des différentes régions du Viêt-Nam qui affirme leur indépendance, mais également aux multiples jeux de pouvoirs qui caractérisent le nationalisme vietnamien. La prise de contrôle de la sûreté par les Binh Xuyen en 1954, montre clairement que l’efficacité opérationnelle de la police n’est pas l’objectif essentiel des nominations pour l’empereur Bao Dai.
Firmes et travailleur.ses dans le jeu politique européen : deux poids pour une mesure
Authors: Cloteau Armèle , Louis Julien
Published: September 2018

On pourrait penser que l’Union européenne constitue une institution favorable au développement d’un syndicalisme international et d’un rapport de force équilibré avec les firmes multinationales. En réalité, dans l’espace de la représentation des intérêts, syndicats et patronat ne possèdent ni le même volume ni le même type de ressources, les firmes s’appuyant sur des fonds propres et des experts plus spécialisés. Au-delà, comme le démontrent Armèle Cloteau et Julien Louis, les dispositifs de participation avantagent largement les organisations les plus dotées et tendent à domestiquer l’action des syndicats par leur forte institutionnalisation. Les pratiques de représentation des intérêts, en majorité informelles, se réalisent surtout dans des relations d’interconnaissance : l’industrie a ici un avantage majeur en raison des carrières de ses représentants, marquées par la circulation dans les institutions européennes.
Faire progresser le droit. Un enjeu des alliances entre syndicats et ONG contre l’impunité des multinationales
Authors: Corpet Marthe
Published: September 2018

La lutte contre l’impunité dont les multinationales bénéficient est menée depuis de nombreuses années par la société civile, à travers des alliances entre syndicats et ONG. La loi du 27 mars 2017 qui instaure un devoir de vigilance pour les entreprises multinationales est le fruit de cette bataille et constitue une première mondiale. Cette avancée législative constitue également un point d’appui important dans les négociations en cours à l’ONU pour qu’un traité international soit adopté et fasse reculer l’impunité des multinationales partout dans le monde.
Globaliser le modèle de l’organizing : les luttes de gouvernance et le renouveau syndical
Authors: K. McCallum Jamie
Published: September 2018

Les mobilisations des personnels d’entretien ou « Justice for Janitors » (J4J) organisées par le syndicat des services SEIU en 1990 aux Etats-Unis ont mis en œuvre de nouvelles formes d’action syndicale. La lutte contre la firme multinationale de services de sécurité G4S menée par SEIU associé à UNI Global Union a permis de mettre à l’épreuve de l’internationalisation ces nouvelles pratiques. L’article se propose de décrire cette transformation du syndicalisme en révélant le modèle politique qu’elle fait émerger, un modèle d’organizing. Ce dernier consiste à sortir du face-à-face traditionnel employeurs-employé.es, en s’appuyant sur des ressources locales, sur une stratégie totale qui vise à repenser les cibles de la lutte, ainsi que sur des solidarités syndicales internationales. Les luttes syndicales apparaissent alors comme des luttes de gouvernance qui visent moins à arracher quelque chose à l’entreprise qu’à peser sur la fabrique des règles du jeu.
Lost in translation : la délicate importation de la campagne Fight for 15 en France
Authors: Pasquier Vincent
Published: September 2018

Né en 2012 aux États-Unis, le mouvement Fight for 15 vise à la fois à faire progresser le salaire minimum et à syndiquer les salarié.es à faibles revenus du secteur des services. Porté principalement par le syndicat SEIU, le combat pour 15 dollars marque par son ampleur inédite, sa stratégie innovante et une série de victoires a priori improbables. En 2014, alors en plein essor aux États-Unis, le mouvement cherche à s’internationaliser et tente notamment de favoriser l’émergence d’actions en France. Mais le scénario à succès déployé aux États-Unis semble bien difficile à mettre en œuvre dans l’Hexagone, en raison notamment de l’inertie des principaux acteurs syndicaux.
Taking the Wheel: Patient Driving in Clinical Psychiatry
Authors: Holoyda Brian J. , Landess Jackie , Scott Charles L. , Newman William J.
Published: September 2018

Driving is a complex task involving mental functions including attention, concentration, visual and auditory perception, and gross and fine motor control. Psychiatric illness and the use of psychotropic medications and illicit drugs, not surprisingly, can affect patients' driving abilities. Clinically, many psychiatrists may not evaluate patients' driving or discuss the risks of patients' medication and substance use on their driving. Some experts and the American Psychiatric Association have noted that psychiatrists are not specially equipped to evaluate driving and, therefore, should not be held liable for patients' negligent driving. Some notable cases indicate that psychiatrists may be held liable for a patient's negligent driving, even months after discharge from an inpatient setting. This article reviews what is known about various psychiatric conditions and driving, the effect of medications and cannabis on driving, as well as duties that psychiatrists may have in managing patients' driving-related risk of harm.

[
Psychiatr Ann.
2018;48(9):421–426.]
From True Threat to Trigger Warnings: A Primer on Forensic Assessment of Speech
Authors: Ferranti Jessica , Scott Charles L. , McDermott Barbara
Published: September 2018

The First Amendment protects freedom of speech as an essential right of Americans. It has long been established that a “true threat” is not afforded protection because the law recognizes that a verbal threat can cause harm, even if the threat is never carried out. The last decade has seen an expansion of formal and informal claims of emotional harm due to verbal statements and the content of college curricula. A new lexicon has developed describing and attempting to regulate verbal content that some people claim cause emotional harm, including “microaggression,” “trigger,” “trigger warning,” and “safe spaces.” A culture of vindictive protectiveness characterized by heightened vigilance on speech and retaliatory litigiousness is discussed in this article. We also discuss forensic assessments of emotional harm from speech claims as we highlight the ever-present tension between our desire for safety and civil liberties in this evolving area of forensic practice.[Psychiatr Ann.2018;48(9):427–432.]
Towards Bioelastomers via Coordination Polymerization of Renewable Terpenes Using Neodymium-Based Catalyst Systems
Authors: Díaz de León Ramón , López Ricardo , Valencia Luis , Mendoza Ricardo , Cabello Judith , Enríquez Javier
Published: September 2018

Syntheses of biolestomers through the coordination polymerization of terpenes, such as ocimene (Oc), β-myrcene (My) andtrans-β-farnesene (Fa), using catalyst systems based on neodymium versatate (NdV3) are reported in this work. All polymerization products were characterized by size exclusion chromatography, differential scanning calorimetry and nuclear magnetic resonance in order to determine their macromolecular, thermal and structural characteristics. The NdV3in combination with diisobutylaluminum hydride as cocatalyst and diethylaluminum chloride (DEAC) as halogen source was found effective for Oc polymerizations providing polyocimenes with molecular weights (Mn) in the order of 20 to 57 Kg/mol, broad molecular weight distributions (Mw/Mn) since 3.8 until 8.2, preferablycis-1,4 content (61-69 %) and glass transition temperatures (Tg) in the range of-30 to-26 °C. On the other hand, the same NdV3but now activated by modified methylaluminoxane and DEAC was found considerably active in My and Fa polymerizations, affording polymyrcenes and polyfarnesenes withMnbetween 155 and 243 Kg/mol, as well asMw/Mnranging between 3.1-3.9 and 1,4 content values were found higher than 94 % for this subfamily of polyterpenes, being the 3,4 content the complement for completing 100 %. Moreover, it was demonstrated thatTgof polyterpenes studied depends on the size of pendant group, shifting it towards lower temperatures as increasing the size of the pendant group.
Potential in the Development of Borneo Acacia Wood Reinforced Polyhydroxyalkanoates Bio-Composites
Authors: bin Bakri Muhammad Khusairy , Jayamani Elammaran , Kakar Akshay
Published: September 2018

This research focuses on the mechanical and morphological properties of acacia wood (AW) reinforced polyhydroxyalkanoates (PHA) bio-composites. Acacia woods waste in the form of sawdust was processed into short wood fiber, which was later mixed with pure PHA with different fiber loading (5wt%, 10wt%, 15wt% and 20wt%). The acacia wood fibers were chemically modified by using the naturalization technique (which used both acidic and alkaline base) using acetic acid and sodium bicarbonate. The hot press machine was used to fabricate the samples. Tensile and flexural samples were fabricated and tested according to the ASTM standards. The SEM images show that the chemically modified acacia wood reinforced PHA (M-AW-PHA) bio-composites create desirable adhesion which contributed to better mechanical strength at 15wt%, when compared with untreated acacia wood reinforced PHA (U-AW-PHA) bio-composites.
Cementitious Composites with Low Water Permeability through Internal Hydrophobicity
Authors: Baghban Mohammad Hajmohammadian , Holvik Ole Kristian , Hesselberg Eivind , Javadabadi Mohaddeseh Tahanpour
Published: September 2018

Three different hydrophobic agents were considered for internal hydrophobation of cementitious composites. The dosage varied between one and two percent of cement weight and these admixtures were introduced to the composite during the mix procedure. capillary suction test, pore protection factor (PF) test and compressive strength test where conducted for material characterization. The results show reduction in water permeability of modified samples and rapeseed oil was the most effective admixture between these agents. While water resistance in the PF test of the modifies samples were increased between 21% to 33%, the compressive strength was reduced between 10% to 18%. In cases where reducing water permeability is a major challenge in cementitious composites, using rapeseed oil for internal hydrophobation can be an environmentally friendly solution.
Fabrication and Characterization of Novel Bone Void Filler Made from Hydroxyapatite-Rice Starch Composite
Authors: Punyanitya Sittiporn , Punyanitya Warangkul , Thiansem Sakdiphon , Koonawoot Rungsarit
Published: September 2018

The aim of this study is fabricated bone void filler (BVF) made from hydroxyapatite (HA)-rice starch (RS) composite. We provided HA derived from cockle shells and RS derived from Thai rice starch. BVF was prepared by adding the pore former method to mimic the pore structure of bones. The samples were heated at 1250°C for 3 hours. Then, the composites were prepared by dipping and coating surface of the samples with RS gel. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) confirmed that bovine bone and BVF are made of HA phase. Film of RS gel coated on surface of samples indicated that BVF without toxicity and would increased the proliferation of bone cells. Moreover, it was found that BVF after coated RS gel had water absorption value higher than before coated as 25% that exhibited a good capacity of regeneration bone.
Surface Hydrophilic Modification of Polypropylene Fiber by Hydrolysis of Silane Coupling Agent
Authors: Fei Yi Wei , Ma Jun , Sun Shian , Tong Li Ping , Liu Hong Ming
Published: September 2018

Silane coupling agent is applied to modify polypropylene fiber. The modification effectively transfers the hydrophobic surface of polypropylene fiber to hydrophilic surface. Results from FT-IR, SEM and contact angle meter suggest that that the surface functional groups, the morphology and hydrophilia of polypropylene fiber is changed during the hydrolysis reactions of silane coupling agent. The modification process not only improve the surface hydrophilia of polypropylene fiber, but also convert the smooth surface of unmodified fibers to rough surface of modified fibers which gives stronger interface bonding force between fiber and substrate in the field of composite applications.
ZnO Tetrapods for Potential Photocatalytic Dye Degradation
Authors: Sadyk Shynggys , Atabaev Timur Sh.
Published: September 2018

In this study, a facile method was used to prepare ZnO tetrapods for potential dye degradation applications. Field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX) and UV-Vis spectroscopy were employed to investigate the morphology, chemical composition, and photocatalytic properties of prepared ZnO tetrapods. A Rhodamine B (RB) dye was used as a model dye to study the photocatalytic activity of the prepared sample. It was shown that RB dye can be efficiently degraded in the presence of ZnO tetrapods under continuous UV-light illumination. Thus, prepared ZnO tetrapods with excellent photocatalytic properties can be potentially used in wastewater treatment.
Structural Effects on Perovskite Phase Formation for PZT Powders Obtained by Polymeric Precursor Method
Authors: da Silva Margarete Soares , da Silva Lucas L. , de Souza Eliane F. , Ramos Talita Cuenca Pina Moreira , de Sá Igor Silva , Barbosa Graciele Vieira , Longo Elson , Cavalheiro Alberto Adriano
Published: September 2018

Many synthesis methods are available to obtain a set of specific characteristics for lead zirconate titanate (PZT) piezoelectric ceramic powders. In this work, we have successfully prepared PZT powder samples through the Polymeric Precursor Method with x = 0.6, according the general formula Pb (ZrxTi1-x)O3. The powders were thermally treated from 380 to 550 oC and characterized by Raman spectroscopy and X-ray diffraction (DRX) in order to evaluate the effects of thermal treatment on the phase formation and the crystallization processes. The results obtained by Raman spectroscopy were compared to refined crystal data obtained by Rietveld method, leading to coherent conclusions about the structural effects occurring along the temperature of calcination. It was possible to characterize the tetragonal perovskite phase as predominant phase occurs only after 500 oC, but its crystallinity is already determined by synthesis method. Thus, no ordering process is verified for perovskite as a function of the temperature increasing during thermal treatment, in spite of the continuous pyrochlore-to-perovskite phase transition. The pyrochlore secondary phase starts to vanish before its proper crystallization process, changing the tetragonality of previously formed perovskite phase.
Brick Drying Simulations by Finite Volume Method
Authors: Santos R.S. , Peña D.P.A. , Diniz D.D.S. , Costa G.A. , Queiroz J.G.A. , Neto S.R.F.
Published: September 2018

There are numerous studies on the application of ceramic materials, such as bricks, in the various engineering and manufacturing fields. Ceramic bricks are manufactured from humidified clay and are classified as structural ceramics. When exposed to drying the process is not precisely controlled, defects such as cracks, deformations and warping can arise, which compromise the final physical and structural properties of the product. Seeking to solve the procedure through simulations, this work presents a numerical study on a brick drying. A three-dimensional transient model is presented to predict the temperature of the holed ceramic brick and the distribution of the humidity content in a drying situation inside a temperature controlled oven, the heat transfer and mass phenomena are present. As simulations were done in the ANSYS CFX® program, which uses the Finite Volumes Method and presented satisfactory results when compared with the experimental works.
Use of Waste from Construction and Demolition in the Manufacture of Soil-Cement Bricks: A Sustainable Alternative
Authors: de Macêdo Reis Lívia Racquel , do Nascimento Filho Ilvio Romero Oliveira , Reis Ian Gustavo Rodrigues Veloso , de Abreu Vieira Pablo , Brasileiro Luzana Leite , de Matos José Milton Elias
Published: September 2018

The search for preserving the environment and avoiding the scarcity of natural resources leads civil construction to seek new technical measures tending to the sustainability of its activities, among them, the use of soil-cement bricks and construction and demolition waste (CDW), contributing to the reduction of materials discarded and costs in the works. This research aims to partially incorporate CDW in the manufacture of soil-cement bricks, with 25% and 50% of the soil mass replaced. Soil and CDW mixtures with 8%, 10% and 12% of cement were submitted to compaction tests. Soil-cement and CDW-cement bricks were submitted to dimensional analysis, water absorption tests and simple compression strength at 14 days. The results confirmed the potential of the CDW as a partial raw material for the preparation of soil-cement bricks as the results of the absorption tests achieved desired results. The brick with 25% of CDW and 12% of cement presented the best resistance to compression. The use of CDW as a construction material enables the reduction of waste-disposal areas and provides the manufacture of environmentally sustainable materials.
Phenomena of Capillarity and Drying in Gypsum Blocks: Development of Experimental Apparatus for the Characterization of Representative Specimens
Authors: de Campos Emanuel Patrick , de Vasconcelos Ferraz Andrea
Published: September 2018

The construction market has at its disposal more and more technical solutions in sealing materials that allow cost reduction and short term execution for construction companies. Among these solutions are the so called gypsum blocks. In spite of their countless advantages when it comes to their use as masonry sealing material, there are limits to the use of gypsum blocks: due to their low resistance to deterioration by rain, their use as external sealing is not recommended. Therefore, the aim of the present work was the development of experimental apparatus for the analyses of capillary phenomena in representative samples of gypsum blocks for sealing. The development of these apparatus for capillarity tests was based on models for tests of liquid water flow in porous media – standardized by procedure 11.2 according to RILEM TC 25-PEM (1980). By means of the obtained results it was possible to verify the high accuracy of the apparatus, seeing that considerable differences were observed in values of capillary absorption coefficient for specimens with water/gypsum ratios of 0.5; 0.6; 0.7 and 0.8 (results varied from 14.75 g cm-2h-0,5 for ratio 0.5 and 58.99 g cm-2h-0,5 for ratio 0.8). Additionally, tests with water repellent additives were carried out, verifying that the developed apparatus is able to identify the influence of these additives in representative specimens of gypsum blocks.
Physical Properties, Mechanical Strength and Microstructure of Fired Clay Brick Waste and Metakaolin Geopolymer Mortars
Authors: Schwaab S. , Ueno O.K. , Ganasini D. , Folgueras M.V. , Correia Sivaldo L.
Published: September 2018

This paper presents a study related to the application of geopolymers cements as a binder on production of mortars for construction and building materials. Geopolymeric cements were produced from metakaolin, clay brick waste and activator consisting of potassium hydroxide and potassium silicate. The mixtures were prepared using standard production processes according Brazilian standards. Hardened properties of density, water absorption, 7-day and 28-day compressive strength were evaluated on samples of cured mortars. Selected samples of fractured specimens were subjected to microstructural characterisation via scanning electron microscopy, X-ray diffraction and thermal analysis. The results for the 7-day and 28-day compressive strength of geopolymer mortars showed that these materials have properties as good as those obtained from Portland cement mortars. Microstructural characterization of fractured pieces showed a morphology usually found in the category of geopolymers product structures.
Study of the Effect of Compatibility Agents in the Incorporation of Rice Hull Ash in Polypropylene Compounds: Mechanical Properties
Authors: Oliveira Morgueto Natalia , de Cássia Dutra Nunes Edilene , Codelo Nascimento Fernando , Haruo Saito Newton
Published: September 2018

The present work aimed at incorporating the rice hull ash (RHA) into a polypropylene polymer matrix. The methodology applied was the case study, whereby the rice hull, residue generated during the grain extraction, was used in the present study. The samples were prepared with the addition of a coupling agent (silane) with 10% by mass in relation to the filler, to improve the characteristics of the ash/ matrix interface. The tensile test results showed that the modulus of elasticity increased proportionally to the addition of the RHA contents, promoting an increase in the material stiffness. The micrographs showed excellent adhesion between the RHA particles and the polymer matrix. proving the coupling, because there was a good wettability array load due to the use of the coupling agent. The results show the feasibility of use of CCA in the composite with PP.
Hybrids Obtained from Monoglyceride of Castor Oil with Hydroxyapatite for Applications in Bioinduction of Bone Tissue: Synthesis and Characterization
Authors: de Albuquerque Mendes Milton Thélio , Nobre Francisco Xavier , de Matos José Milton Elias
Published: September 2018

In this paper, we report the initial research to obtain hybrids (PU@Hap-1%, PU@Hap-2% and PU@Hap-3% compound by hydroxyapatite (Hap) synthesized by coprecipitation (CP) method, with monoglycerides (MG) of castor oil (Ricinus communis) polymerized with hexamethylene diisocyanate (HDI). Hap, was characterized by X-ray diffraction (XRD), Rietveld refinement, Fourier transform infrared (FTIR), RAMAN spectroscopy and X-ray fluorescence (XRF). Hybrids, MG and castor oil, were characterized by Fourier transform infrared (FTIR). XRD patterns and Rietveld refinement analysis confirmed that hexagonal phase for nanostructure for Hap, with average size particles D  12 nm, obtained by Scherrer equation and ration Ca/P = 2.13 (m/m) confirmed that XRF spectroscopy. FTIR and RAMAN spectra exhibited all active modes for vibrational stretches (1, 2, 3 and 4) of the phosphate groups () and vibrational modes of O-H bonds, present in the hexagonal structure for Hap in a ranger from 400 to 4000 cm-1 and 400 to 1100 cm-1, respectively. The conversion of castor oil (triglyceride) to MG, was monitored by FTIR spectroscopy, confirmed that increase of intensity active modes in 3317 cm-1 and 1741 cm-1, corresponding to the vibrations modes of O-H and C=O, respectively. Finally, we observed that all active modes in FTIR spectroscopy, corresponding to the hybrids: PU@Hap-1%, PU@Hap-2% and PU@Hap-3%, and Polyurethanes – PU (standard), confirmed the increase of intensity mode of the phosphate group with the increase of Hap in the polymerization of the mixture MG with HDI.
Study of Double Walled Corrugated Cardboard as an Alternative Material for Eco-Friendly Designed Furniture
Authors: Sales Rosemary Bom Conselho , Franco Annibal Gouvêa , Mohallem Nelcy Della Santina , Paulino Aguilar Maria Teresa
Published: September 2018

The global production capacity of corrugated cardboard used in packaging increased by 3.5% per year in the last decade. These packages have limited life span and, after use, contribute for increasing the waste stream on the planet. An interesting alternative for their reuse is the manufacture of unconventional furniture and objects. Nevertheless, there are few studies addressing the performance of cardboard for their application in furniture products. In this study we characterized corrugated cardboard by scanning electron microscopy, energy dispersive spectroscopy. X-ray diffraction, determination of the basic weight of paper (grammage), resistance to burst, column compression and uniaxial compression of test samples manufactured with a specific geometry. Results indicate that cardboard can be a material of great feasibility and workability to be used in furniture design.
Phase Formation in Copper and Calcium Titanate Dielectric Ceramic Obtained by Polymeric Precursor Method
Authors: Barbosa Graciele Vieira , Gonçalves Sabrina Vitor , Kawahara Creuza Kimito Caceres , Amoresi Rafael Aparecido Ciola , da Silva Margarete Soares , Stropa Jusinei Meireles , de Oliveira Lincoln Carlos Silva , Cavalheiro Alberto Adriano
Published: September 2018

The polycrystalline ceramic named calcium and copper titanate is a dielectric ceramic with very high dielectric constant applicable in several electronic devices. The powder form for that advanced ceramic can be synthesized through chemical route, like the Polymeric Precursor Method at relative lower temperatures the presence of alkaline earth cations harms the structural homogenization during the crystallization process. In this work, the calcium and copper titanate powder was obtained by Polymeric Precursors Method by imposing a slow thermal decomposition of polymeric precursor and several crushing steps before the calcination at 800 °C for 4 hours. The entire process was observed by thermogravimetric analysis and FTIR spectrometry, including the nitrogen adsorption-desorption isotherms and X-ray diffractometry techniques for calcined power samples. It was observed the crystallization of the cubic Im-3 Ca1/4Cu3/4TiO3phase only starts after organics removal and full calcium carbonate elimination above 700 oC, which is followed by pore elimination and particle sintering. The chemical synthetic route used in this work shows the ability to prepare CCT powders sample with very structural homogeneity, which characteristics are required to manufacturing many electronic devices.
Generation of Latex Films on Glassy Substrates by Evaporation Induced Self-Assembly (EISA) Process
Authors: Rodrigues Wagner Cirilo , dos Santos Silva Antony Ernesto , Lima Phabyanno Rodrigues , dos Santos Sousa Jonas , de Freitas Alan John Duarte , de Freitas Johnnatan Duarte , de Albuquerque Barros Filho Djalma
Published: September 2018

It will be discussed in this work how it is possible to produce latex films by evaporation induced self-assembly (EISA) process. Latex beads were synthesized in a cylindrical flask without N2flow. The polymerization process of styrene happens at water as solvent and with the presence of persulfate potassium as initiator. The final product was a dispersion of spherical nanometric particles (ɸ = 0.47 ± 0.06μm) whose concentration can be changed from 0.5 to 10% (V/Vo). These dispersions were spread on glassy substrates at 50°C over a square area (~1cm2) with control of solvent evaporation. The films are transparent and they show the formation of nanowire structures by scanning electron microscopy (SEM) characterization. Such structures were associated to high affinity of latex beads particles to form cylindrical arrangements due to presence of O2during their synthesis. It has been concluded that this self-assembly structure can be very worthy for generation of functional devices like sensors, solar cells and biomaterials.
Morphological and Structural Analyses in Carbonated Magnesium-Aluminum Hydrotalcites Co-Substituted with Iron III
Authors: Kawahara Creuza Kimito Caceres , Barbosa Graciele Vieira , de Sá Igor Silva , Gonçalves Sabrina Vitor , Amoresi Rafael Aparecido Ciola , Zaghete Maria Aparecida , da Silva Margarete Soares , Cavalheiro Alberto Adriano
Published: September 2018

Magnesium-aluminum hydrotalcites can be co-substituted with others trivalent cations, such as iron III in aluminum site, which can be a promising way to modify the properties of that synthetic adsorptive material. In the present work, hydrotalcite containing 5 mol% iron III in co-substitution to the aluminum was prepared by precipitation process and compared with no co-substituted sample along the temperature of calcination at 100 and 500 oC for 4 hours. The calcined samples were characterized by simultaneous TG/DTA, X-ray Diffraction and nitrogen adsorption-desorption techniques. The iron (III) insertion showed positive results in order to provide more stable structure against high temperatures of calcination, which was observed by lesser structural decomposition of rhombohedral hydrotalcite and a more mesoporous structure.
PA6/Sodium Clay Membrane for Application in Petroleum Sector
Authors: Mota Matos Maria Carmo Cabral , Araújo Edcleide Maria , Damião Leite Amanda Melissa , Medeiros Keila Machado , de Lima Carlos Antônio Pereira
Published: September 2018

Membrane is a barrier that separates two phases and limits, totally or partially, the transportation of one or various chemical species present in the phases. In this study, were obtained membranes of polyamide6 (PA6)/sodium clay from the technique immersion-precipitation. Membranes were characterized by diffraction of X-ray (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and the permeation of water vapor. For DRX, verified the disappearance of the clay characteristic peak, indicating obtaining an exfoliated and/or partially exfoliated structure. Analysis by DSC indicated that the presence of the clay leading to an increase in the crystallinity of the membranes. SEM photomicrographs showed that the presence of clay caused changes in membrane morphology and pore formation. In the water vapor permeation, the presence of clay promoted an increase in the permeability of membranes to be compared with the pure PA6 membrane. Thus, these membranes have potential for the treatment of effluents from industry of oil.
Modeling and Simulation of Nucleation and Growth Transformations with Nucleation on Interfaces of Kelvin Polihedra Network
Authors: da Fonseca Guilherme Dias , Alves André Luiz Moraes , da Costa Marcos Felipe Braga , Lyrio Mariana Sizenando , Assis Weslley L.S. , Rios Paulo Rangel
Published: September 2018

Nucleation is a phenomenon associated to the start of the new phase, from a primary phase, named matrix. Growth is the increase in size of this new phase over time. In metallic materials, the nucleation may take place on the grain boundaries of the primary phase. A network of Kelvin polyhedra was used in this paper to represent the grains. A computer simulation was performed in which nucleation took places at the faces, edges and vertices of this polyhedral network. The Causal cone method was employed in the simulations. The results of the present computational simulations were compared with the classical Johnson Mehl-Avrami-Kolmogorov (JMAK) as well as with Cahn model for nucleation at the grain boundaries. JMAK theory considers nuclei to be uniform randomly located within the matrix. Cahn analytical model specifies that nucleation takes place on random planes. For a small number of nuclei, the simulations approached the JMAK model whereas as the number of nuclei increased the simulation results agree with Cahn's theory. Reasons for this are fully discussed.
Evolution of Individual Grains in 3d Microstructure Generated by Computational Simulation of Transformations Involving Two Phases
Authors: Alves André Luiz Moraes , da Fonseca Guilherme Dias , da Costa Marcos Felipe Braga , da Silva Assis Weslley Luiz , Rios Paulo Rangel
Published: September 2018

In the phase transformations of the solid state, situations can occur in which the initial phase transform forming two or more distinct phases. The exact mathematical model for situations where more than one transformation occurs simultaneously or sequentially was proposed by Rios and Villa. The computational simulation was used to study the evolution and visualization of the possible microstructures that these transformations may present. The causal cone methodology was adopted. The simulations were compared with the analytical model to ensure that they occur as expected. The growth of individual grains of each phase was monitored in 3D microstructure evolution. With this monitoring, was possible to extract useful data able to quantify the simulated 3D microstructure. Quantifying the simulated microstructures increase the possibility of the simulations give to the experimentalist insights about the transformations. In this paper, it is verified that each grain evolves in an individual way, as expected, however their growth is similar.
The Effect of Iron (III) Co-Insertion in Magnesium-Aluminum Hydrotalcites Obtained by Precipitation Method at pH 11
Authors: de Sá Igor Silva , Kawahara Creuza Kimito Caceres , Barbosa Graciele Vieira , de Souza Eliane F. , Ramos Talita Cuenca Pina Moreira , Amoresi Rafael Aparecido Ciola , da Silva Margarete Soares , Cavalheiro Alberto Adriano
Published: September 2018

Hydrotalcite are anionic clay material presenting LDH arrangement and high porosity and specific areas, which make it a good adsorbent for pollutant species in water. Besides that, that material type can be used as catalyst or catalyst support in several industrial processes. The most common compositions is based on metallic mix hydroxide with high content of magnesium, but their adsorptive properties arise from aluminum replacement in layer structure. The present work presents the synthesis of carbonated magnesium-aluminum hydrotalcite through the precipitation method in order to investigate the co-insertion of iron (III) in aluminum site. It was found the iron (III) co-inserted samples obtained at 100 and 200 oC for 4 hours present no substantial harming in relation to the common magnesium-aluminum composition. All of the samples presented high porosity and specific area, becoming an alternative anionic adsorptive.
Electrochemical Behavior of Hot Treated Ti-12Mo-8Nb Alloy
Authors: Nunes Aline Raquel Vieira , Gabriel Sinara Borborema , Araújo Leonardo Sales , Nunes Carlos Angelo , de Almeida Luiz Henrique
Published: September 2018

Several beta titanium alloys are finding ever-increasing applications in biomaterials, due to the combination of its mechanical properties including low elasticity modulus, high strength, fatigue resistance and good ductility with improved corrosion resistance. In this regard, a new beta titanium Ti-12Mo-8Nb alloy was developed as an alternative to the traditional alloy Ti-6Al-4V. Studies have shown that the release of vanadium (V) and aluminum (Al) ions in the human body may cause cytotoxic effects and neurological disorders, respectively. Additionally, this new alloy presented higher ratio of hardness to elastic modulus, as compared to the commercial Ti-6Al-4V alloy. This paper presents the electrochemical behavior and mechanical properties of the Ti-12Mo-8Nb heat treated at 950 oC for 1h under high vacuum and then water quenched. The electrochemical behavior was carried through potentiodynamic polarization curves using Ringer's solution to simulate the body fluid. The Ti-12Mo-8Nb alloy presented a microstructure consisting of β phase with good mechanical properties and a passive layer was formed.
Study of the Abrasion Resistance of Fe-Cu-Nb and NEXT 100® Metallic Matrices for the Manufacture of Diamond Tools
Authors: de Oliveira Hellen C.P. , Batista Adriano Corrêa , Perpétuo Genivaldo Júlio , Leal Thales Eduardo , Reis Ana Carolina Fernandes , Assis Paulo Santos , Filgueira Marcello
Published: September 2018

The substitution of cobalt, present in the commercial binder metal matrix commonly used by the industry, was analyzed: 25,2%Fe-49,5%Cu-24,1%Co – NEXT 100® by the niobium element of the Fe-Cu-Co system, obtaining 4 metal matrices: 28,34%Fe–56,66%Cu–15%Nb; 25%Fe–50%Cu–25%Nb; 21,67%Fe–43,33%C–35%Nb; 18,34%Fe–36,66%Cu–45%Nb. This study aims to evaluate the behavior of metal matrices to better choose the type of matrix to be used in the manufacture of diamond tools. The metal powders were blended according to the compositions of each metal matrix and then hot pressed at 800o /35MPa / 3min, thus occurring the sintering. The sintered samples of each metal matrix were conducted to the Abrasion Resistance test in order to verify the wear, for the accumulated times of 2, 6, 12 and 20 minutes. In these metal matrices, density, porosity and Vickers hardness (HV5) tests were performed to better understand the wear suffered by the samples. Thus, the metal matrix 25% Fe-50%Cu-25%Nb presented, in the general context of the properties and from the abrasive point of view, satisfactory results capable of replacing the NEXT 100 matrix.
Relationship between Electrical Conductivity and the Stage of the Heat Treatments of Aging and Overaging of the Aluminum Alloy AA2024
Authors: Oliveira Paulo Junho , Melo Mirian Lourdes Noronha , Silva Renato Sergio Mello , Caixeta Daniel Oliveira
Published: September 2018

The aluminum alloys of the 2xxx series have been widely used in structural applications because the interesting combination of their good mechanical properties and their low weight. This interesting combination of properties is only possible because of the heat treatments and the control of these properties deserves special attention because these alloys "age" over time as a function of the temperature to which they are submitted. The studies of the respective thermal treatments and the behavior of these properties in function of these treatments can lead to the development and the validation of a simple, fast and nondestructive test to control the useful life of the components. The objective of this work is to evaluate the possibility of the use of eddy currents to evaluate the mechanical properties of the AA2024 alloy in different conditions: annealed, solubilized, aged and over-aged, that is, through the electrical conductivity and hardness obtained in the respective heat treatments in other words, through the electrical conductivity and hardness obtained in the respective heat treatments, be able to obtain a relation between them, in such a way that, with the measured conductivity value, it is possible to predict the aging stage in which the alloy is found, without having to resort to a destructive test. Samples of the alloy, as received, were submitted to over-aging treatment, using temperatures between 250°C and 415°C for times of 8 min to 24h. In a second step, samples of this alloy were submitted to solubilization and artificial aging treatments, and measurements were made of hardness and electrical conductivity and the behavior of electrical conductivity and hardness was also studied. The results indicate good a correlation between hardness and conductivity and this investigation suggests a way to obtain the nondestructive test.
Comparative Analysis of Wear Behavior of Al 7075 Alloy, AISI 1020 and AISI 1045 Carbon Steels
Authors: Santos Ernelison , Alencar Janiclay , Cruz Kleber
Published: September 2018

The main objective of this study is to analyze a comparative research about the tribological behavior of Al7075, AISI 1020 and AISI 1045 steels during the ball crater abrasion wear test (Hutchings, 1996) without the presence of lubricants (abrasive slurry). The tests were performed for each alloy with a load equal to 1.4N, during 5, 10, 15 and 20 minutes and the rotation used was equal to 230 rpm. Scanning electron microcopy and optical microscopy were used to characterize the worn samples. The wear resistance was measured by calculating the worn volume (V), with the basis on the diameter of the crater produced by the rotating sphere. [1,2,4]. According to the results, the alloy Al7075 presented the lower wear resistance and the AISI 1020 and AISI 1045 steels obtained a similar wear behavior, probably due to the presence of carbon, which makes the hardness increase. However, when the sliding distance is about 276 m, the wear resistance of AISI 1045 steel falls indicating that AISI 1045 may present lower wear resistance for longer sliding distances
Effect of Passivation Treatment on Adhesion and Protective Properties of Steel Coated with Polymeric Film
Authors: Zumelzu Ernesto , de Melo Hercílio G. , di Sarli Alejandro R. , Tomachuk Célia Regina
Published: September 2018

The surface of steel coated with Cr3+-based passivation layer and polyethylene therephtalate (PET) polymeric film was investigated by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). This coating was applied to the steel surface through a co-lamination industrial procedure. As well, the coated steel porosity was characterized by BET (Brunaer, Emmert, Teller) gas adsorption technique. Basic aspects of the polymer adhesion to the passivated steel were also studied by determining the force and energy adhesion between them. The AFM results showed that the PET coating presents roughness in the nanometer scale. XPS diagrams indicated the absence of surface contaminants and flaws on the applied coating and low contaminant levels on the Cr layer and absence of Cr6+peaks after coating removal. This material can be a environmental compliant alternative to replace tinplate and Cr6+conversion layer in the food industry, being compatible with the packed product.
Diffusion Analyses Using GDOES Technique of the 22MnB5 Press Hardened Steel with Al-Si and Zn-Ni Coatings
Authors: Couto C.P. , Politano R. , Gomes Maurilio Pereira , Colosio M.A. , Rossi Jesualdo Luiz
Published: September 2018

The hot stamping process consists to heat the steel blank, at total austenitization temperatures and to transfer it into the press tooling for forming and fast cooling to fully martensitic transformation. This transference from furnace to press stage promotes some steel oxidation. The application of metallic coatings avoids this phenomenon. The Al-Si coating, a patented process, has been the most applied on steel. Hence, alternative coatings like Zn-Ni are under development. It is known that this furnace heating causes chemical elements diffusion that results in intermetallics formation. This study had the objective of analyze the diffusion profiles of chemical elements present in the substrate, 22MnB5 steel, and coatings of Al-Si and Zn-Ni, using glow-discharge optical emission spectroscopy - GDOES and to correlate the results with those obtained with energy dispersive X-ray spectroscopy - EDS. The results showed that for the Zn-Ni sample, the Zn and Fe profiles at the interfacial zone, are predominant; which justify the high proportion of ZnFe phases as showed using scanning electron microscopy - SEM images. For the Al-Si sample at the interfacial zone, the profile of Al and Fe varies simultaneously; besides that, silicon diffusion in the substrate is more effectively than the nickel diffusion. For this reason, it was possible to identify AlFeSi phase near to the steel substrate.
Characterization of Biomaterial and Tissue Response Analysis after Implantation
Authors: Câmara-Pereira Eliana dos Santos , Rolim Ana Emília Holanda , Barreto Isabela Cerqueira , Moraes Laise Monteiro Campos , Campos Lilian , de Campos Michelle Oliveira Mendes Carneiro , Barbosa Junior Aryon de Almeida , Rossi Alexandre Malta , de Albuquerque-Santos Silvia Rachel , Rosa Fabiana Paim
Published: September 2018

Some biomaterials can be used to promote tissue repair process. The biological substitutes (biomaterials such as hydroxyapatite beads) can be used with some advantages and purpose of mimicking responses to on-site repair of the injured bone. The objective of this study was to evaluate the osteogenic potential of the biomaterial composed of hydroxyapatite and alginate in place of the critical defect. bioceramic samples stoichiometric hydroxyapatite was produced by the precipitation method, wet method with ion molar ratio of Ca 10 (PO 4) 6 (OH) 2, in which the Ca / P ratio was equal to 1.67. The reaction conditions were favorable to the composition of a biomaterial with crystalline phase. The synthesis of the biomaterial composed of hydroxyapatite and alginate microspheres (HAAlg5%; 200 ø 425mm) was obtained from two primary solutions with the aim of, in optimal reactive conditions, to form the precipitate. After synthesis the microspheres were implanted into the defect site. The potential effects of using HAAlg5% and the application of vibratory waves in the critical defect repair were unknown and the results described in this study are promising, considering the systemic therapy and at the site of injury. The biomaterial used promoted repair the injured tissue.
Microstructural Evaluation of a 5052 H34 Aluminum Alloy Used in Multilayered Armor
Authors: Pereira Artur Camposo , de Oliveira Braga Fabio , Monteiro Sergio Neves , de Azevedo Thales Moreira , Braga Wesley Soares
Published: September 2018

Among the aluminum alloys, the 5052 has been extensively investigated aiming at high rate deformation applications, owing to its high mechanical strength, plasticity and toughness. In this work, the microstructure and microhardness of a 5052 H34 alloy were investigated. This alloy was subjected to ballistic impact with 7.62 mm ammunition as back layer of a multilayered armor system composed of a ceramic and a composite material. An increase in the microhardness was observed. However, changes in the microstructure were not significant. The fracture aspect of the alloy in the high deformation rate was compared to that of a tensile tested sample. A stronger plastic behavior was verified in ballistic tested samples.
Dechroming: An Alternative Treatment for Leather Shavings, to Obtain a Biocompatible Collagen without Environmental Impacts
Authors: Balarim Nelissa Garcia , Cavalcante Dalita Gomes Silva Morais , Gomes Andressa Silva , Cabrera Flavio Camargo , Job Aldo Eloizo
Published: September 2018

One of the biggest problems facing the leather industry is the production of solid waste with chromium. Dechroming process remove chrome from leather waste and it is designed to recover the value of collagen in the waste. Thus, the aim of this study was try to improve a methodology of dechroming process already described in the scientific literature, seeking to increase the percentage of dechroming ratio, as well as to evaluate the cytotoxic and genotoxic effects of the dechromed samples obtained from the leather residue for possible applications that require non-toxic materials based on collagens. As results, the dechroming process has been shown to be effective, with 99.29% of chromium removed from the shavings. In addition, it is possible to infer that the process of dechroming performed in this study was efficient in the neutralization step of hexavalent chromium and that the collagen from the leather residue did not shows cytotoxic and genotoxic effects for the evaluatedin vitrotest system. Therefore, this treatment allows to obtain a valuable product extracted from what was previously a hazardous waste.