bluuebunny/crossref_metadata_2025 huggingface dataset:
Dil: The Crying Game, espectatoralidade e agenciamento trans em Traídos pelo Desejo
Authors: Spitzner Marcelo
Published: June 2019

Este artigo, através de uma perspectiva transfeminista e queer, discute um recorte do filme Traídos pelo Desejo, como pertence a um campo que convencionalmente tem-se chamado de Trans Cinema. Através da discussão do filme busca-se, além de problematizar o conceito de gaze, a partir de um viés binário, propor uma espectatoralidade agencial da personagem trans. Essa espectatoralidade e agenciamento da personagem Dil são possíveis através de um momento, que pode ser observado em vários filmes do Trans Cinema, em que o personagem experimenta uma ruptura com o sentimento de medo ou da exposição a potencial violência, é um momento de intenso engajamento fílmico que permite uma fuga temporária do domínio cinematográfico dos efeitos negativos de cenas constrangedoras. A esse momento poderíamos chamar de “ válvula de escape” e pode estar associado a diversos elementos, tais como sonho, fantasia, dança, etc. Nesse filme, associo-o a performance da música (ou músicaescape) The Crying Game.Palavras-chave: Trans Cinema; Espectatoralidade; Gaze; Agenciamento; Teoria queer.
UMA ANÁLISE SOBRE A “CAMPANHA PERMANENTE CONTRA OS AGROTÓXICOS E PELA VIDA”
Authors: Cover Maciel , Rodrigues Patrícia Silveira
Published: June 2019

No contexto em que o Brasil se torna o principal consumidor mundial de agrotóxicos, um conjunto de atores sociais como movimentos sociais do campo, organizações não governamentais, sindicatosrurais e urbanos, organizam a “Campanha Permanente contra os Agrotóxicos e pela Vida” com o intuito de chamar a atenção para a sociedade brasileira diante do eminente risco que estes produtos químicos acarretam para a saúde humana e para o meio ambiente. Por meio desse artigo propomos refletir sobre o processo desenvolvido por esta campanha a partir da seguinte questão: que fatores podem ser mobilizados para explicar o crescimento em termos organizativos da Campanha Permanente contra os Agrotóxicos e pela Vida? O artigo é fundamento na análise de materiais produzidos pela campanha, bem como pelas adesões de novos atores sociais que adentraram na campanha desde seu começo. Em termos teóricos, buscamos nos fundamentar nas discussões sobre sociedade global de risco de Ulrich Beck bem como no conceito de sistemas peritos de Anthony Giddens.Palavras-Chaves: Agrotóxicos; Movimentos Sociais do Campo; Sociedade Global de Risco; Sistemas Peritos.
POPULAÇÕES TRADICIONAIS: IDENTIDADES, MEIO AMBIENTE E CONFLITOS FUNDIÁRIOS
Authors: De Andrade Neto João Augusto
Published: June 2019

RESUMO Nas últimas décadas um fenômeno social despontou na sociedade brasileira, chamando a atenção de pesquisadores e mediadores que trabalham junto a segmentos rurais. Trata-se da visibilização de conflitos envolvendo o acesso à terra e a outros recursos naturais, nos quais a categoria “populações tradicionais” ganha crescente destaque, indicando a existência de grupos que assumem identidades como quilombolas, indígenas, ribeirinhos, quebradeiras de coco babaçu, faxinais, fundo de pasto, dentre outras denominações. Fundamentalmente reivindicam o reconhecimento estatal da garantia do direito à terra, ao meio ambiente, à manutenção de modos de vida historicamente constituídos e a políticas públicas voltadas especificamente para esses segmentos da sociedade. Além das questões ambientais e culturais que apontam para particularidades de cada um desses grupos específicos, é possível identificar um traço comum a várias situações distintas de conflitos sociais envolvendo “populações tradicionais”: a disputa fundiária envolvendo os territórios historicamente ocupados por tais grupos. Pretende-se levantar alguns elementos que permitam discutir a relação entre a identidade de grupos presentes no chamado mundo rural brasileiro, conhecidos como “populações tradicionais”, e o lugar dos conflitos sociais vivenciados por esses segmentos em meio ao secular problema fundiário no país. Partir-se-á de uma abordagem histórica sobre a categoria “populações tradicionais” no Brasil, para em seguida problematizar a categoria e discutir a sobreposição dos critérios ambiental e fundiário no que tange aos conflitos vivenciados por tais grupos sociais.Palavras-chave: Populações tradicionais; identidades; conflitos fundiários.
ENSAIOS DE SOCIOLOGIA DA CIÊNCIA: MAIS QUE UMA COLETÂNEA, UM MAPA DA VISÃO MERTONIANA SOBRE CIÊNCIA
Authors: Coelho Gabriel Bandeira , Massaú Guilherme Camargo
Published: June 2019

Resenha da Obra: MERTON, Robert. Ensaios de sociologia da ciência. São Paulo: Editora 34, 2013.
O PERIGO DE SER JOVEM E NEGRO NO BRASIL: UM OLHAR SOBRE A ADOLESCÊNCIA NUMA PERSPECTIVA RACIAL
Authors: Macedo Aldenora Conceição de , Felipe Herculano Pereira
Published: June 2019

Impulsionado pelos acontecimentos que envolvem a adolescência do Brasil, na atualidade, este trabalho apresenta de forma breve o percurso trilhado historicamente em busca de ressignificação da adolescência. Aponta a questão racial como fator legitimador de todo um processo de vulnerabilização que acomete a população negra e, neste caso, a adolescência. Nesse sentido busca ressaltar o peso do racismo no que diz respeito à violência urbana por meio de pesquisas estatísticas e demonstra, como um alerta, o local de perigo constante - suscetível a todo tipo de violência, até mesmo a violência letal, ocupado pelo jovem negro na sociedade. É um trabalho de revisão bibliográfica cujo objetivo é o despertar para uma reflexão sobre os rumos que estão norteando legal e socialmente a adolescência e as ameaças políticas que visam cercear seus direitos. A conclusão é a de que se há algum interesse em se combater essa realidade violenta e desigual, deve estar aliado às políticas de prevenção que visam melhoria das condições de vida da população negra como um todo. Fomentando a articulação e integração de esforços de diferentes áreas e entre diferentes níveis de governo. Somente assim se faz possível transformar a realidade a que estão sujeitos milhões de jovens negros brasileiros.
Economia e política da transição democrática no Brasil: uma análise dos governos FHC, Lula e Dilma
Authors: Belieiro Junior José Carlos Martines
Published: June 2019

O objetivo principal do trabalho é contribuir aos estudos de economia e política nas ciências sociais, com foco de análise na transição democrática brasileira e no debate sobre a relação entre redemocratização política e crise econômica. O artigo se concentra  na análise dos governos FHC, Lula e Dilma, buscando analisar aspectos políticos e econômicos dos três diferentes governos, como a política econômica, a questão da inflação, o papel do Estado na economia, estabilidade econômica e a crise final do governo Dilma, ocorrida em abril de 2016. O trabalho sugere que a crise final do governo Dilma e o impeachment representam um ponto de inflexão no processo de transição democrática e a uma crise nas promessas da Constituição de 1988. O trabalho foi elaborado especialmente para o seminário Transição Democrática: aspectos sociológicos e políticos, que ocorreu na UFPel em novembro de 2015.Palavras-Chave: Crise econômica e democracia; Economia e política da transição democrática; Governos FHC, Lula e Dilma.
Editorial
Authors: Norus Equipe Editorial
Published: June 2019

É com satisfação que a Revista Novos Rumos Sociológicos (NORUS), do Programa de Pós-Graduação em Sociologia (PPGS) da Universidade Federal de Pelotas (UFPel), em seu sexto número publica o Dossiê “A atualidade de Henri Lefebvre”.  Nesse dossiê, organizado por Carlos Roberto da Silva Machado e William Héctor Gómez Soto, professores e pesquisadores da Universidade Federal de Rio Grande (FURG) e da Universidade Federal de Pelotas (UFPel), destaca-se a contribuição do pensamento de Henri Lefebvre para a compreensão da sociedade contemporânea a partir de trabalhos que apresentam interlocuções teóricas e metodológicas com sua obra
A rebelião do vivido. Henri Lefebvre no centro de Salvador
Authors: Uriarte Urpi Montoya
Published: June 2019

Este artigo pretende trazer Henri Lefebvre para o centro de Salvador: usar suas ideias e categorias para interpretar alguns discursos e cenas na capital baiana, demonstrando como o que ele chamou de direito à cidade está sendo exigido hoje no Pelourinho e como o que ele denominou de a rebelião do vivido está acontecendo em espaços centrais, tais como a Avenida Sete de Setembro. O material empírico que este artigo analisa à luz das ideias e categorias lefebvrianas são um documento da Associação de Moradores e Amigos do Centro Histórico (AMACH) e o cotidiano de um vendedor de castanhas e camarão seco na Rua do Forte.
A vida cotidiana na Belle Époque do Rio Grande-RS
Authors: Ortigara Andrea Maio
Published: June 2019

O presente artigo objetiva constituir um panorama sobre como a sociedade rio-grandina se inseriu no mercado cultural e econômico mundial entre os anos 1900 e 1920, refletir sobre o modo como esse período foi vivenciado, e analisar características do cotidiano e dos processos de ajustamentos urbanos. Para tanto, as questões referentes ao cotidiano e ao urbano serão fundamentadas a partir do pensamento de Henri Lefèbvre, que defende a noção de cotidiano como instrumento de conhecimento e de análise da realidade social, dando visibilidade à dinâmica dos processos de mudança na sociedade. Como complemento a essa base teórica, apresentamos os registros pessoais em forma de diário manuscrito e álbuns fotográficos de um sujeito que vivenciou esse período. Assim, procuramos demonstrar uma articulação entre o urbano, o cultural e o cotidiano, a partir das transformações que redefiniram a imagem das cidades e de seus habitantes no período Belle Époque.
3-Dimensional structural control of silica microparticles using photoresponsive materials
Authors: Ikawa Taiji , Furukawa Tomoya , Shibata Hidenori , Narita Mamiko , Mouri Makoto , Watanabe Osamu , Tawata Masahiro
Published: June 2019

We demonstrate the three-dimensional arrangement of silica microparticles in body-centered cubic lattice structure using both a relief pattern formed in the film of the azopolymer and silica micro particles dispersed in a nematic liquid crystal. In the method, firstly, the square lattice relief structures with the spacing of 2000 nm and the depth of 400 nm were formed on the azopolymer film by twice exposure to two beam interference patterns with coherent light of 488 nm in wavelength from Ar ion laser. Next, a nematic liquid crystal (5CB) containing 2000 nm diam. silica microparticles, with the surface modified with silane coupling reagent giving rise to homeotropic texture, was dropped on the relief structure on the azopolymer. The two dimensional square lattice structures of the micropaticles were formed spontaneously in an isotropic to nematic phase transition. Finally, the microparticles were three-dimensionally arranged by using optical tweezers. The microparticles were successfully stacked in a four-step pyramid structure with body centered tetragonal lattice structure.
Concentrated colloidal dispersion of decanoic acid self-assembled monolayer protected CeO2 nanoparticles up to 77 wt% in nonpolar organic solvents
Authors: Arita Toshihiko , Yoo Jungwoo , Ueda Yu , Adschiri Tadafumi
Published: June 2019

Self-assembled monolayers (SAMs) of decanoic acids were prepared on cerium oxide nanoparticles (NPs). The dispersion of the NPs was improved by increasing the packing density of decanoic acid SAM on the NPs. Highly concentrated ceria nanofluids more than 22 vol% (about 77 wt%) in cyclohexane and trans-decalin were achieved, according to the criterion to the packing density and chain length of the alkanoic acid of the SAM to disperse the ceria NPs in nonpolar organic solvents proposed previously. Temperature effect on the dispersion was also examined and it was turned out that the dispersion was strongly enhanced with activation of Brownian motion.
Enhanced photocurrent due to interband transitions from InAs quantum dots embedded in InGaAs quantum well solar cells
Authors: Vasan R. , Makableh Y. F. M. , Sarker J. C. , Manasreh M. O.
Published: June 2019

Solar cells based on InAs quantum dots embedded in InxGa1-xAs quantum wells grown on n-type GaAs substrate were fabricated and tested. Solar cells with In mole fraction (x) in the range of 0-40% were investigated. The performance of the solar cells was evaluated using current-voltage characteristics, spectral response, and quantum efficiency measurements. The spectral response and quantum efficiency spectra possess several peaks along the lower energy side of the spectra, which are attributed to the interband transitions in the structure. These peaks are red shifted as x is increased above 0 %. The device power conversion efficiency was extracted from the current-voltage characteristics using an AM 1.5 solar simulator. The short circuit current density increased as the x is increased above 0 %. But the overall power conversion efficiency decreased due to decrease in the open circuit voltage. The decrease in open circuit voltage is due strain induced dislocations caused by lattice mismatch.
High Energy Density, High Operating Frequency and Energy Efficient On-Chip Inductors based on Coiled Carbon Nanotubes (CCNTs)
Authors: Faraby H. , Bandaru P. R.
Published: June 2019

We demonstrate the superior inductive properties of coiled carbon nanotubes (CCNTs) through numerical computation and analytical modeling, for the next generation of nanoscale, on-chip inductors. Taking advantage of the kinetic inductance (Lk), particularly evident at the nanoscale we find that the inductance can be increased by three orders of magnitude through changing the tube radius as well as the coil radius while the device footprint of the CCNTs can be reduced by 60%. By varying the geometric parameters of the coiled structure, the external magnetic inductance (LM,ext) can be as high as 20% of the Lk. We also report that the self resonant frequency (fSR) of CCNTs can be as much of the order of THz whereas the fSR of conventional copper(Cu) spiral inductors are limited to around 40GHz. Moreover when the material volume is considered, CCNTs have the potential to achieve Quality Factor (Q) eight times as Cu and when the footprint volume is considered Q can be twice as Cu All these promising properties of CCNTs make them a potential candidate for the entire frequency spectrum.
Investigation of Quantum Dot Solar Cell Device Performance
Authors: Beattie Neil S. , Zoppi Guillaume , Farrer Ian , See Patrick , Miles Robert W. , Ritchie David A.
Published: June 2019

The device performance of GaAs p-i-n solar cells containing stacked layers of self-assembled InAs quantum dots is investigated. The solar cells demonstrate enhanced external quantum efficiency below the GaAs band gap relative to a control device without quantum dots. This is attributed to the capture of sub-band gap photons by the quantum dots. Analysis of the current density versus voltage characteristic for the quantum dot solar cell reveals a decrease in the series resistance as the device area is reduce from 0.16 cm2 to 0.01 cm2. This is effect is not observed in control devices and is quantum dot related. Furthermore, low temperature measurements of the open circuit voltage for both quantum dot and control devices provide experimental verification of the conditions required to realise an intermediate band gap solar cell.
Reactive Laser–Sputtering for Amorphous Silicon Films
Authors: Hanabusa M. , Suzuki M.
Published: June 2019

Intense, Q-switched Nd:YAG laser pulses were used to vaporize a silicon target. The pulsed atomic vapor generated produces amorphous silicon films at unusually fast accumulation speeds of 106 Å/s. Despite this speed, reactive deposition is made possible simply by evaporating in a reactive gas atmosphere. For instance, hydrogenated films have been produced by evaporating in hydrogen. Atomic hydrogen generated by thermal decomposition at a laserirradiated target spot is responsible for hydrogenation. Dynamics of this laser-induced deposition have been studied by a spectroscopic technique.
Evaluation of a Thermoelectric Device Utilizing Porous Medium
Authors: Yasuda Hideyuki , Ohnaka Itsuo , Inada Yoichi , Nomura Kimitaka
Published: June 2019

ABASTRACT:

A thermoelectric device consisting of the porous part and the bulk part was proposed. Increase of heat exchange area due to porous medium will improve the efficiency of heat exchange between heating/cooling sources and the device. Estimation based on physical properties of FeSi2 indicated that generated power of the partially porous device per unit area can be several times higher than that of the bulk one in case of gas heating / cooling system. The partially porous thermoelectric devices were produced. In measurement of power, it has been confirmed that generated power per unit area of the partially porous FeSi2 devices was roughly 10 times higher than that of the conventional device. The proposed porous device will exhibit its advantage in the case of low heat transfer coefficient between the device and the heating / cooling sources.
Synthesis and Characterization of Large Single Crystals of Silicon and Germanium Clathrate-II Compounds and a New Tin Compound with Clathrate Layers
Authors: Bobev Svilen , Sevov Slavi C.
Published: June 2019

We have synthesized large single crystals of clathrate-II compounds with frameworks of silicon and germanium by employing mixed alkali metal countercations. The combinations of alkali metals are rationally selected in order to fit the different cages of the clathrate-II structure. This approach leads to the following stoichiometric and fully “stuffed” compounds: Cs8Na16Si136, Cs8Na16Ge136, Rb8Na16Si136 and Rb8Na16Ge136. The structures and the corresponding Si-Si and Ge-Ge distances are elucidated and established with high accuracy from extensive single crystal X-ray diffraction work. The compounds are stoichiometric, metallic, and are very stable at a variety of extreme conditions such as heat, concentrated acids, hydrothermal treatment etc. No evidence was found for vacancies in the silicon and germanium networks or partial occupancies of the alkali metal sites. The stoichiometry of these fully “stuffed” clathrates is consistent with the measured temperature independent Pauli paramagnetism, supported also by the conductivity measurements on single crystals and thermopower measurements on pellets. A new compound with novel clathrate-like structure forms when small and large cations are combined with tin. The new materials, A6Na18Sn46 (A = K, Rb, Cs), are made of clathrate layers and the interlayer space filled with Sn4-tetrahedra and alkali-metal cations. Its formula can be rationalized as A6Na6Sn34 + 3·Na4Sn4 (one clathrate layer and three tin tetrahedra). The compound is stable in air and is being currently tested at other conditions. Detailed measurements of its transport properties are under way.
Artificially Atomic-scale Ordered Superlattice Alloys for Thermoelectric Applications
Authors: Cho S. , Kim Y. , DiVenere A. , Wong G. K. L. , Freeman A. J. , Ketterson J. B. , Olafsen L. J. , Vurgaftman I. , Meyer J. R. , Hoffman C. A. , Chen G.
Published: June 2019

We report artificially atomic-scale ordered superlattice alloy systems, new scheme to pursue high-ZT materials. We have fabricated Bi/Sb superlattice alloys that are artificially ordered on the atomic scale using MBE, confirmed by the presence of XRD superlattice satellites. We have observed that the electronic structure can be modified from semimetal, through zero-gap, to semiconductor by changing the superlattice period and sublayer thicknesses using electrical resistivity, thermopower, and magneto-transport measurements. InSb/Bi superlattice alloys have also been prepared and studied using XRD and thermopower measurements, which shows that their thermoelectric transport properties can be modified in accordance with structural modification. This superlattice alloy scheme gives us one more tool to control and tune the electronic structure and consequently the thermoelectric properties.
Compositional And Structural Modifications In Ternary Bismuth Chalcogenides And Their Thermoelectric Properties
Authors: Chung Duck-Young , Lane Melissa A. , Ireland John R. , Brazis Paul W. , Kannewurf Carl R. , Kanatzidis Mercouri G.
Published: June 2019

Based on the versatile combination of PbQ- and Bi2Q3-type (Q = S, Se, Te) fragments, we explored new compounds in the Pb/Bi/Se ternary system. The new class of compounds, Pb5Bi6Se14, Pb5Pb12Se23, and PbBi8Se13 are homologues with different combination of alternating Bi2Se3- and PbSe-type layers. α- and β-Pb6Bi2Se9 were obtained in different synthetic conditions and the former is isostructural to heyrovskyite (Pb6Bi2S9) while the latter is a NaCl-type cubic phase. Pb5Bi6Se14 shows a power factor of 11.2 μW/cm·K2 with electrical conductivity of 657 S/cm and thermopower of -131 μV/K at 271 K. The most significant characteristic of this material is the extremely low thermal conductivity of less than 1.0 W/m·K at room temperature. On the basis of these properties, a preliminary doping study for Pb5Bi6Se14 with Sn, Sb, and SbBr3 as dopants was undertaken and the results are presented in this report.
Exploring Complex Chalcogenides for Thermoelectric Applications
Authors: Wang Ying C. , DiSalvo Francis J.
Published: June 2019

Our research on ternary / quaternary chalcogenides for thermoelectric applications has lead to the identification of new interesting compounds and better understanding of the chemistry and physical properties of complex chalcogenides. The chemical, geometric, electronic diversity and flexibility has been well demonstrated in BaBiSe3 and Sr4Bi6Se13 type compounds. This presents both a challenge and more opportunity in controlling and optimizing the thermoelectric properties of these complex chalcogenides, compared with elemental and binary compounds. The importance of multivalley band structure in thermoelectric materials is emphasized. Only compounds with high crystal symmetry have the possibility of having a large number of degenerate valleys in the conduction bands or peaks in the valence bands, respectively. However, most of the complex chalcogenides crystallize in low crystal symmetry. An Edisonian method of exploratory synthesis and characterization may be the working approach to find good thermoelectric materials with ZT higher than 4.
Structure and Thermoelectric Properties of New Quaternary Tin and Lead Bismuth Selenides, K1+xM4-2xBi7+xSe15 (M = Sn, Pb) and K1+xSn5-xBi11+xSe22
Authors: Mrotzek Antje , Choi Kyoung-Shin , Chung Duck-Young , Lane Melissa A. , Ireland John R. , Brazis Paul W. , Hogan Tim , Kannewurf Carl R. , Kanatzidis Mercouri G.
Published: June 2019

We present the structure and thermoelectric properties of the new quaternary selenides K1+xM4–2xBi7+xSe15 (M = Sn, Pb) and K1-xSn5-xBi11+xSe22. The compounds K1+xM4-2xBi7+xSe15 (M= Sn, Pb) crystallize isostructural to A1+xPb4-2xSb7+xSe15 with A = K, Rb, while K1-xSn5-xBi11+xSe22 reveals a new structure type. In both structure types fragments of the Bi2Te3-type and the NaCl-type are connected to a three-dimensional anionic framework with K+ ions filled tunnels. The two structures vary by the size of the NaCl-type rods and are closely related to β-K2Bi8Se13 and K2.5Bi8.5Se14. The thermoelectric properties of K1+xM4-2xBi7+xSe15 (M = Sn, Pb) and K1-xSn5-xBi11+xSe22 were explored on single crystal and ingot samples. These compounds are narrow gap semiconductors and show n-type behavior with moderate Seebeck coefficients. They have very low thermal conductivity due to an extensive disorder of the metal atoms and possible “rattling” K+ ions.
Characterization of New Materials in A Four-Sample Thermoelectric Measurement System
Authors: Ghelani Nishant A. , Loo Sim Y. , Chung Duck-Young , Sportouch Sandrine , Nardi Stephan de , Kanatzidis Mercouri G. , Hogan Timothy P. , Nolas George S.
Published: June 2019

Several new materials in the CsBi4Te6, A2Bi8Se13, (A = K, Rb, Cs), HoNiSb, Ba/Ge/B (B = In, Sn), and AgPbBiQ3 (Q = S, Se, Te) systems have shown promising characteristics for thermoelectric applications. New synthesis techniques are able to produce samples at much higher rates than previously possible. This has led to a persistent challenge in thermoelectric materials research of rapid and comprehensive characterization of samples. This paper presents a description of a new 4-sample transport measurement system and the related measurement techniques. Special features of the system include fully computer-controlled operation (implemented in LabView™) for simultaneous measurement of electrical conductivity, thermo-electric power, and thermal conductivity. This system has been successfully used to characterize several new thermoelectric materials (including some of the above-mentioned compounds) and reference materials exhibiting a wide range of thermal conductivities.
The Dynamics of Avalanching Bead Chains
Authors: Bretz Michael , Rojo Alberto G.
Published: June 2019

Avalanching studies were performed on 2D beds of a unique granular material - uniform length, 2.06 mm diameter flexible metal bead chain. The dynamical behavior of the slowly rotating vertical chain beds was separately characterized using chain lengths of 1, 2, 5, 9 and 13 beads, respectively. Digital images were acquired at 30-second intervals and analyzed to provide comparisons of mean profiles, slope angle variations, avalanche mass distributions and surface step discontinuities. This study is designed to probe how elongation, flexing and rolling affect avalanching through interlocking and polymer-like behavior.
Ultrasound propagation in disordered granular media
Authors: Jia Xiaoping
Published: June 2019

We have identified, according to the ratio of the wavelength to the grain size, two distinct types of pulsed ultrasound transmission through a dry bead packing under stress: one corresponds to coherent ballistic waves characterized by the effective medium description, the other to the waves scattered by the inhomogeneous stress field within the granular medium. Over long distances of transport, the multiply scattered waves exhibit a diffusive character. Also we investigate the dynamics of the granular medium during a compaction under cyclic loading-unloading. Both the macroscopic deformation and the microscopic rearrangement have been measured, via an ultrasonic correlation technique using the multiple acoustic scattering very sensitive to the change of the system configuration. It is found that as the packing fraction increases, there is a continuous evolution of the system in response to external loading, from an irreversible behavior towards more elastic one.
Analysis of shear bands in slow granular flows using a frictional Cosserat model
Authors: Nott Prabhu R. , Kesava Rao K. , Srinivasa Mohan L.
Published: June 2019

The slow flow of granular materials is often marked by the existence of narrow shear layers, adjacent to large regions that suffer little or no deformation. This behaviour, in the regime where shear stress is generated primarily by the frictional interactions between grains, has so far eluded theoretical description. In this paper, we present a rigid-plastic frictional Cosserat model that captures thin shear layers by incorporating a microscopic length scale. We treat the granular medium as a Cosserat continuum, which allows the existence of localised couple stresses and, therefore, the possibility of an asymmetric stress tensor. In addition, the local rotation is an independent field variable and is not necessarily equal to the vorticity. The angular momentum balance, which is implicitly satisfied for a classical continuum, must now be solved in conjunction with the linear momentum balances. We extend the critical state model, used in soil plasticity, for a Cosserat continuum and obtain predictions for flow in plane and cylindrical Couette devices. The velocity profile predicted by our model is in qualitative agreement with available experimental data. In addition, our model can predict scaling laws for the shear layer thickness as a function of the Couette gap, which must be verified in future experiments. Most significantly, our model can determine the velocity field in viscometric flows, which classical plasticity-based model cannot.
Wavelength Selection in a Vibrated Granular Layer
Authors: Clément Eric , Labous Laurent
Published: June 2019

We present a numerical study of a surface instability occurring in a bidimensional vibrated granular layer. The driving mechanism for the formation of stationary waves is closely followed. Two regimes of wavelength selection are identified : a dispersive regime and a saturation regime. For the saturation regime, a connection is established between the pattern formation and an intrinsic instability occurring spontaneously in dissipative gases. We also address the importance of the detailed dissipation laws determining the wavelength values.
Theory of Stress Distribution in Granular Materials: the Memory Formalism
Authors: Kenkre V. M.
Published: June 2019

A theoretical approach to the description of stress distribution in granular compacts is presented on the basis of a memory function formalism. Experiments which have motivated the approach are mentioned. The formalism is shown to provide an explanation of observed features of stress distribution in compacts, and to lead to existing theories in extreme limits, thereb y providing a unification of the theories. The memory functions are shown to be intimately related to characteristic spatial correlations in the granular system and are discussed on the basis of stochastic considerations.
A New Simple Non Linear Modelling of the Quasi Statics of Granular Media: predictions, comparisons with experiments
Authors: Evesque Pierre
Published: June 2019

First, a non linear incremental modelling is proposed to describe rheological behaviour of granular material under different simple (i.e. triaxial-, oedometric-, undrained-) stress-strain paths. Validity of isotropic-response assumption is demonstrated whatever the stress ratio as far as deformation range remains small (ε1<5%). This contradicts some recent hypothesis made on the evolution of contact distribution during anisotropic loading.
FACET: a two Dimensional Simulator of Polycrystalline thin film Growth
Authors: Zhang Jie , Adams James B.
Published: June 2019

We present FACET: a two dimensional simulator to model polycrystalline thin film growth, which links atomic scale processes to macroscopic phenomena. The model is based on the concept of describing the crystal surface in terms of preferred facets. Line segments were used to depict the profile of the grain and grain boundaries. Multiple nuclei are semi-randomly distributed along the textured or non-textured surface, and crystallographycally appropriate facets are created in the nucleation simulation. We use a Kinetic Lattice Monte Carlo (KLMC) method to calculate the inter-facet diffusion rates and use a continuum approach to grow the facets, hence the multiple grains. The software is Windows(95/98/2000/NT) based and has an integrated Graphical User Interface, within which a user can input deposition conditions and experimental and simulation data, visualize the nucleation and growth of the grains, and obtain the final grain structure and texture.
Calculation of Intrinsic Stresses and Elastic Moduli in Nonhomogeneous Thin Films
Authors: Andia Pedro C. , Costanzo Francesco , Gray Gary L. , Yurick Thomas J.
Published: June 2019

An approach is presented for the determination of the residual stresses and elastic moduli of particle systems resulting from computer simulations of particle or atomic deposition. The proposed technique is based on fundamental concepts of elasticity and is capable of capturing the variation of stresses and moduli as functions of position within the system. Application to a simple particle system consisting of a deposited thin film is demonstrated.
A Method to Simulate the Interface-Diffusion in Solid-State Bonding-Processes Considering the Elastic Deformation
Authors: Ito Takehiko , Saito Shigeki , Takahashi Kunio , Onzawa Tadao
Published: June 2019

We propose a new method to simulate the interface diffusion in the solid-state bonding-process. This method is more significant under the condition of low pressure and low temperature. It is available for the bonding of two bodies which consist of the atoms of the same kind and have slight surface roughness. In a conventional method, the elastic deformation during the bonding process is considered. The interface diffusion is enhanced and the bonding time decreases when the external pressure changes at appropriate frequency. In order to clarify the enhancement effect of changing the pressure, we examine three cases, i.e., the 1st pressure type is constant pressure, the 2nd type is zero pressure, and the 3rd type is the on-off pressure. Our results suggest the on-off pressure decreases the required time for the perfect bonding if we choose on appropriate frequency.
Interactions between Edge Dislocations and Interstitial Clusters in Iron and Copper
Authors: Osetsky Yu.N. , Bacon D.J. , Serra A. , Singh B.N.
Published: June 2019

Dislocations decorated by both clusters of self-interstitial atoms (SIAs) and small dislocation loops, are one of the microstructure features which can play an important role in post-irradiated deformation processes. The interactions between dislocations and clusters are important and are usually treated within the framework of isotropic elasticity theory. However, it is still not clear whether or not these interactions, especially for small clusters at short distances, can be treated accurately by elasticity theory. Comparative studies by atomistic simulation and elasticity theory can clarify this. Here we present a simple example of such a study where interactions between a glissile SIA cluster and an edge dislocation are studied in bcc-Fe and fcc-Cu using both techniques. In Fe we have studied the interaction of a dislocation with Burgers vector b= 1/2<111> lying along <112> direction with a SIA cluster with the same b situated at different distances below the extra half-plane. In Cu, the dislocation and cluster had b = 1/2<110> and the dislocation line was along the <112> direction. Interactions with clusters of diameter about 1nm were simulated. Elastic calculations were made within the isotropic theory with parameters estimated from atomistic simulation. The results obtained by both techniques are discussed and some preliminary conclusions for different cases are drawn.
Unstable Motion of an Edge Dislocation in a Solute Atom Atmosphere Studied by Kinetic Monte Carlo Simulations
Authors: Gu X. M. , Sun Y. Q.
Published: June 2019

The discontinuous yielding of a model material, which contains an edge dislocation moving in the atmosphere of solute atoms, is studied by Kinetic Monte Carlo (KMC) simulations. The stress-strain curves for a constant strain rate were obtained at different temperatures. The dislocation moves discontinuously, producing three types of serrated yielding behavior at intermediate temperatures for different imposed strain rates. Positive dependence of flow stress on temperature and negative strain rate sensitivity were observed in the regime of discontinuous motion. The present model, though highly simplified and not taking into account the collective behaviors of dislocations in real materials, does exhibit some of the basic features observed in experiments.
A Theory for Multi Damage Evaluation of TiN Thin Film
Authors: Misawa Kazunori , Okabe Tomonaga , Yanaka Masaaki , Shimizu Masao , Takeda Nobuo
Published: June 2019

The present paper experimentally studies the cracking phenomena of a TiN thin film on a titanium alloy, and presents a new approach to predict the number of cracks under tensile load. An elastoplastic shear-lag model is developed to obtain the stress distribution caused by the film cracks, which is found to agree well with that calculated with FEM. The number of thin film cracks is predicted using a Monte Carlo simulation using the present approach, and favourably compared with the experimental results.
Modeling of the Heterogeneous Deformation of an Aggregate of Grains
Authors: Erieau Philippe P. , Hoc Thierry P. , Rey Colette C.
Published: June 2019

Multiple layers of an Interstitial Free (IF) steel microstructure are polished and analyzed using EBSP and Orientation Imaging Microscopy (OIM) technique. This enables to build a 3D finite element mesh which represents the actual grains arrangement. Then a 30 % reduction plane strain compression is applied on this mesh in order to capture the heterogeneous deformation of the aggregate. After deformation, many grains show large orientation spreads, and thus do not follow a Taylor type assumption. This computation also shows that the stored energy distribution depends on the chosen definition.
Incorporation of Highly Concentrated Iron Impurities in InP by High Temperature Ion Implantation
Authors: Cesca T. , Gasparotto A. , Habra N. El , Coati A. , Fraboni B. , Priolo F. , Moreira E.C. , Ciatto G. , Bocchi C.
Published: June 2019

Iron was introduced in InP by ion implantation with the aim of obtaining a high concentration of substitutional, electrically active, deep level impurities. A substrate temperature higher than 200 °C was maintained during implantation in order to reduce damage accumulation and Fe defect reactions. The lattice position of the implanted Fe atoms and its modification during annealing treatments was studied by means of Proton Induced X-ray Emission (PIXE) in channeling conditions and correlated with the ion induced damage measured by different techniques. The results show that a high fraction of substitutional Fe atoms is present after the implantation. This fraction is progressively reduced during thermal treatments by increasing the annealing temperature, with the formation of inactive Fe aggregates, probably in the form of small Fe-P complexes.
Dose Rate and Temperature Dependence of Ion-Beam-Induced Defect Evolution in Si and SiC
Authors: Posselt M. , Bischoff L. , Teichert J. , Ster A.
Published: June 2019

A focused ion beam system is applied to investigate the dose dependence of the shape of Ge channeling implantation profiles in Si and SiC at two very different dose rates (1011 and 1018 cm-2 s-1), and for implantation temperatures between room temperature and 580 °C. The competing influence of dose rate and temperature observed is explained in terms of intracascade defect relaxation. For the different implantation temperatures, the time scale for defect reduction is estimated. The results obtained for Si are compared with those for SiC.
Comparison of deep level spectra of MBE- and MOCVD-grown InGaAsN
Authors: Kaplar R. J. , Ringel S. A. , Kurtz Steven R. , Allerman A. A. , Klem J. F.
Published: June 2019

Deep level transient spectroscopy (DLTS) studies of both p-type (uid) and n-type (Sidoped), lattice-matched, 1.05 eV bandgap InGaAsN grown by molecular-beam epitaxy (MBE) are reported, and the results are compared to previous measurements of similar materials grown by metal-organic chemical-vapor deposition (MOCVD). In MBE-grown p-type InGaAsN, two majority-carrier hole traps were observed: H3' (0.37 eV) and H4' (0.51 eV), and no evidence was found for the presence of minority-carrier electron traps. These two traps appear to be similar to two levels, H3 (0.48 eV) and H4 (0.5 eV), previously characterized in MOCVD-grown InGaAsN. In MBE-grown n-type InGaAsN, we observed a shallow distribution of electron levels, E1' (0 < EA < 0.35 eV), as well as a deep electron trap E4' (0.56 eV) and a deep hole trap H5' (0.71 eV). E1' appears to be coincident with a superposition of two levels observed in MOCVD-grown InGaAsN, a shallow distribution termed E1 (0 < EA < 0.20 eV) and a discrete (though broadened) level E3 (0.34 eV). Further, E4' appears to be similar in character to a level observed in MOCVD-grown material, E4 (0.82 eV), although a disparity in activation energy exists. This disparity may be due to a temperature-dependent capture cross-section for one or both levels, a possibility that is currently under investigation. In contrast, H5' appears to have no analogue in MOCVD-grown material and thus may be unique to the MBE growth technique.
Application Of Room-Temperature Photoluminescence For Characterizing Thermally Processed Cz Silicon Wafers
Authors: Kirscht F. , Orschel B. , Kim S. , Rouvimov S. , Snegirev B. , Fletcher M. , Shabani M. , Buczkowski A.
Published: June 2019

PL studies of oxygen precipitation related defects, stress relaxation related defects and doping striations in various silicon materials are presented. The sample spectrum includes a variety of dopant species, and the dopant concentration range covers several 1014 cm-3 to several 1019 cm-3. Lightly doped, precipitation-annealed polished wafers were intentionally contaminated with Fe, Ni and Cu. Several types of epi wafers based on heavily doped substrates have been investigated after full device processing. PL intensity in the investigated doping concentration range is controlled by three basic recombination mechanisms: radiative recombination competing with multi phonon Shockley-Read-Hall (SRH) and Auger recombination. SRH recombination is the major competing mechanism at low dopant concentration, and Auger recombination becomes important at increasing doping levels. Even though not yet fully understood, the PL technique applied in this study has generated practically useful results.
Control of Valence States for Zno And Zns with a Wide-Band Gap by a Codoping Method
Authors: Yamamoto T.
Published: June 2019

We have investigated the electronic structures of p- or n-type doped ZnO and ZnS based on the basis of the analysis of the results obtained by ab initio electronic band structure calculations. We find the doping problems of the two materials. They at highly N-doping levels have the narrow impurity bands at the top of the valence band, where holes are very localized by repulsion effects. As a solution to the doping problems described above, we proposed a codoping method: The deliberate codoping of the donors with N acceptors is essential for the enhancement of N-acceptor incorporation and delocalization of the N-impurity states with the electrostatic energy gain in p-type highly doped ZnO and ZnS.
Organic-semiconductor-based all-solid-state photoelectro chemical cells
Authors: Hudej Robert , Pavlica Egon , Bratina Gvido , Lavrencic-Štangar Urška , Vuk Angela Šurca , Orel Boris
Published: June 2019

3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) layers exhibit significant photoresponse. Despite of unfavorable electronic energy level alignment at the dye/PTCDA interface, photon-to-electron conversion efficiencies as high as 1% were observed.
Structural and Optical Characterization of CuxGaySe2Thin Films under Excitation with Above and Below Band Gap Laser Light
Authors: Xue C. , Papadimitriou D. , Raptis Y.S. , Riedle T. , Esser N. , Richter W. , Siebentritt S. , Nishiwaki S. , Albert J. , Lux-Steiner M.Ch.
Published: June 2019

CuxGaySe2MOCVD and PVD grown films were structurally and optically characterized by Raman, Micro-Raman and photoluminescence spectroscopy. Defect related photoluminescence excitation with wavelengths varying across the material band gap reveals: a) in Cu-rich CuGaSe2films, three band edge splitting due to the spin-orbit interaction and the crystal field, and donor-acceptor pair recombination between a shallow donor and two different acceptor levels, and b) in Ga-rich CuGaSe2films, donor-acceptor pair transitions between quasi-continua of donor and acceptor levels related to potential fluctuations. Raman spectra of CuxGaySe2films, excited by laser light near and below the material band gap, show intense modes at 197cm-1, 187cm-1, and 277cm-1, which can be used as indicators of crystallinity and Ga-content of the films. Polarization- and angular- dependent micro-Raman spectra of MOCVD CuGaSe2indicate that CuxSey-crystallites, dispersed on the surface of Cu-rich films, are grown oriented with their c-axis perpendicular to the film surface.
Micro-Fabricated Thin-Film Fuel Cells for Portable Power Requirements
Authors: Jankowski Alan F. , Hayes Jeffrey P. , Graff R. Tim , Morse Jeffrey D.
Published: June 2019

Fuel cells have gained renewed interest for applications in portable power since the energy is stored in a separate reservoir of fuel rather than as an integral part of the power source, as is the case with batteries. While miniaturized fuel cells have been demonstrated for the low power regime (1-20 Watts), numerous issues still must be resolved prior to deployment for applications as a replacement for batteries. As traditional fuel cell designs are scaled down in both power output and physical footprint, several issues impact the operation, efficiency, and overall performance of the fuel cell system. These issues include fuel storage, fuel delivery, system startup, peak power requirements, cell stacking, and thermal management. The combination of thin-film deposition and micro-machining materials offers potential advantages with respect to stack size and weight, flow field and manifold structures, fuel storage, and thermal management. The micro-fabrication technologies that enable material and fuel flexibility through a modular fuel cell platform will be described along with experimental results from both solid oxide and proton exchange membrane, thin-film fuel cells.
Grain Size and Chemical Composition Effects on the Grain Boundary Resistance of Ceria
Authors: Zhou Xiao-Dong , Anderson Harlan U. , Huebner Wayne
Published: June 2019

Studies related to the effects of grain size (30nm – 5.0μm) on the electrical conductivity of undoped CeO2 and Ce0.90Gd0.10O1.95 were performed. A series of impedance spectra as a function of temperature and grain size were analyzed. It was found that the ratio of the grain boundary resistance to the total resistance became lower with decreasing grain size, increasing temperature or increasing Gd content. For the case of Gd doped CeO2, the source of the grain boundary resistance may be due to the trapping of oxygen ions in the grain boundary area.
Single-Source Approach for The Growth of I-III-VI Thin Films
Authors: Afzaal Mohammad , Deivaraj Theivanayagam C. , O'Brien Paul , Park Jin-Ho , Vittal Jagadese J.
Published: June 2019

The ternary chalcopyrite semiconductors I-III-VI are currently used for photovoltaic solar cell applications. In this study, AgIn5S8 thin films were prepared from a series of single-source bimetalorganic precursors, e.g. [(PPh3)2AgIn(SC{O}R)4] (R = alkyl) by aerosol assisted chemical vapour deposition (AA-CVD). The compounds can be used as single-source precursors for the deposition of ternary compounds (I-III-VI) by one-pot reaction using CVD process and they are found to be air stable, which is favourable in comparison with metal alkyl compounds, which are found to be pyrophoroic. The optimum growth temperature for the preparation of these films on glass and Si(100) substrates, was found to be above 350°C in terms of crystallinity, although deposition occurred at low temperatures. The films have been investigated using XRD, SEM and EDS. SEM analysis shows that all films are microcrystalline but have different morphologies depending on the growth temperatures. XRD results show evidence of the crystalline nature of these films. The results of this comprehensive study are presented and discussed.