Neste trabalho, utilizamos o desenvolvimento recente do método DFT/LDA-1/2 para cálculos de estados excitados em materiais. Começamos com um resumo da teoria do funcional da densidade (DFT) e incluímos uma introdução ao método LDA-1/2 para cálculos de excitações em sólidos. Na compilação dos resultados esperamos ter demonstrado a utilidade do LDA-1/2 para cálculos de alinhamentos de bandas em junções semicondutor/semicondutor e semicondutor/isolante. A aplicação do método envolve o conhecimento da química básica dos sistemas. Para tanto, escolhemos sistemas importantes para diversas aplicações, e cujos modelos de simulação estão o limite ou fora do alcance de metodologias que envolvem alto custo computacional, mas que foram bem caracterizados experimentalmente. Concentramos nossas ações no estudo da capacidade preditiva do LDA-1/2 para alinhamentos de bandas, os chamados band offsets, particularmente importantes para a micro e optoeletrônica. Quando não foi possível compararmos nossos resultados com o experimento, procuramos a comparação com métodos estado-da-arte como GW. Bons resultados foram obtidos para band gaps e band offsets de interfaces A1As/GaAs, Si/SiO2, A1N/GaN e CdSe/CdTe, que representam os diferentes tipos de jun_c~oes poss__veis, com (e.g. A1As/GaAs, A1N/GaN) e sem (e.g. Si/SiO2, CdSe/CdTe) ^anions omuns, com (e.g. A1As/GaAs) e sem (e.g. CdSe/CdTe, Si/SiO2) casamento de parâmetros de rede e diferentes tipos de alinhamentos (\"straddling\", e.g. A1As/GaAs ou \"staggered\"e.g. CdSe/CdTe). Analisamos de maneira sistemática o comportamento do entorno do bandgap ao longo da interface, verificando plano a plano atômico o comportamento das bordas de valência e condução com LDA-1/2 em comparação com o LDA, ou comparando diferentes modelos dentro do LDA-1/2, como o caso do CdSe/CdTe e do Si/SiO2. Para o caso A1As/GaAs, aproveitamos o casamento de parâmetros de rede dos semicondutores constituintes e tentamos um modelo de interface de ligas A1xGa1-x As/GaAs para estudar a variação de valência, condução e bandgap em função da composição x. No AlN/GaN, estudamos também os offsets com as contribuições dos orbitais separadamente. Em todos os casos o LDA-1/2 levou-nos a resultados interessantes com modelos simples. A exploração de novas fronteiras de aplicação do método fez-se necessária com a diminuição da dimensionalidade dos sistemas, de 3D (bulk ) para 2D (interfaces) e depois para 1D, ou seja, _os quânticos (\"nanofios\"). Nosso material de estudo para os foi o ZnO que, além da motivação oriunda de conhecidas aplicações em optoeletrônica, apresenta desafios para simulações bulk com qualquer método, e que foi abordado com certo sucesso usando o LDA-1/2 anteriormente, sendo que para fios quânticos encontramos resultados interessantes em geometrias triangulares que facilitaram os modelos. Calculamos o bandgap ZnO bulk e de nanofios passivados e não passivados com hidrogênios usando LDA e LDA-1/2 sem polarização de spin. As estruturas de bandas e o bandgap como função do diâmetro do ano_o foram calculados e ajustes com funções de decaimento foram feitos para comparação, por extrapolação, dos bandgaps com valores experimentais. Foi possível comparar nossos resultados de fios com o bulk, e predizer uma faixa de variaação de bandgaps que os experimentais podem encontrar para nanofios triangulares de ZnO. Também foi feita análise de energias de confinamento em fios quânticos de ZnO, comparando o LDA com LDA-1/2. Finalmente, mostramos os resultados de uma oportunidade de aplicação do método a um material com defeitos, recentemente descoberto e promissor, e com enorme mercado potencial em fotocatálise, o Ti1-O4N. Nosso trabalho envolveu a aplicação do LDA-1/2 a um problema muito desafiador, e.g. a geração de energia limpa, especificamente a separação da molécula de água para produção de hidrogênio. O desafio maior vem da dificuldade de predição de bandgaps teoricamente, em particular para sistemas grandes como é o caso de modelos atomísticos com defeitos, devido aos altos custos computacionais envolvidos. Tais dificuldades forçam os pesquisadores a usarem parâmetros ajustáveis ou métodos semi-empíricos, ou modelos simplificados demais para descrever precisamente resultados experimentais. Isto dificulta o estudo dos sistemas fotocatalíticos potencialmente eficientes e que não foram ainda caracterizados ou otimizados. O LDA-1/2 é aqui validado para esta classe de materiais, abrindo assim a oportunidade para estudar sistemas mais realísticos e complexos para cálculos ainda mais precisos, particularmente para geração de energia limpa. Em particular, modelamos o TiO2 na estrutura rutile com nitrogênio substitucional, cuja estrutura eletrônica é ainda debatida. Foi a primeira aplicação do LDA-1/2 a sistemas com algum tipo de defeito, com ótimos resultados para o novo sistema Ti1- _O4N com vacâncias de Ti. / In this work, we used the recent development of DFT/LDA-1/2 method for calculations of excited states in materials. We begin with a summary of the density functional theory (DFT) and included an introduction to the method LDA-1/2 for calculations of excitations in solids. In compiling the results we hope to have demonstrated the usefulness of the LDA-1/2 for calculating alignments of bands at junctions semiconductor / semiconductor and semiconductor / insulator. The method involves the knowledge of basic chemical systems. To do this we chose systems important for several applications, and simulation models which are the limit or beyond the reach of methodologies involving high computational cost, but have been well characterized experimentally. We focus our actions in the study of the predictive capability of the LDA-1/2 for alignments of bands, the band called offsets, particularly important for micro and optoelectronics. When it was not possible to compare our results with experiment, we compared the methods with state of the art as GW. Good results were obtained for band gaps and band offsets of interfaces A1As/GaAs, Si/SiO2, A1N/GaN and CdSe / CdTe, which represent the different types of jun_c poss__veis-tions, with (eg A1As/GaAs, A1N/GaN) and without (eg Si/SiO2, CdSe / CdTe) ^ omuns anions with (eg A1As/GaAs) and without (eg CdSe / CdTe, Si/SiO2) matching network parameters and different types of alignments (\"straddling\" eg A1As/GaAs or \"staggered\" eg CdSe / CdTe). Systematically analyze the behavior of the environment along the interface bandgap, plane by plane scanning behavior of the edges atomic valence and conduction with LDA-half in comparison with LDA, or comparing templates within the LDA-1 / 2, as the case of CdSe / CdTe and Si/SiO2. For the case A1As/GaAs, we take the marriage of network parameters of semiconductor components and try an interface model alloys A1xGa1-x As / GaAs to study the variation of valence, conduction and bandgap as a function of composition x. In the AlN / GaN, we also studied the offsets with the contributions of the orbitals separately. In all cases the LDA-half led us to interesting results from simple models. The exploration of new frontiers of the method was necessary to decrease the dimensionality of the systems, the 3D (bulk) for 2D (interfaces) and then to 1D, ie, quantum _os (\"nanowires\"). Our study material for the ZnO was that, apart from the motivation coming from known applications in optoelectronics, presents challenges for bulk simulations with any method, and that was addressed with some success using the LDA-half earlier, and for wireless find interesting results in quantum triangular geometries that facilitated models. We calculate the bandgap and bulk ZnO nanowires passivated and not passivated with hydrogen using LDA and LDA-1/2 without spin polarization. The bandgap structures and strips as a function of the diameter of ano_o adjustments are calculated and decay functions for comparison were made by extrapolation of the bandgaps with experimental values. It was possible to compare our results with the bulk of wires, and predict a range of bandgaps that variaação can find experimental triangular ZnO nanowires. It was also made analysis of energy confinement in ZnO quantum wires, comparing LDA with LDA-1/2. Finally, we show the results of an opportunity to apply the method to a material with defects, newly discovered and promising, and with huge market potential in photocatalysis, the Ti1-O4N. Our work involved the application of LDA-1/2 to a very challenging problem, eg the generation of clean energy, specifically the separation of the water molecule for hydrogen production. The main challenge has been the difficulty of predicting bandgaps theoretically, in particular for large systems such as the model atomistic defects because of the high computational costs involved. These difficulties force the researchers to use adjustable parameters or semi-empirical methods, or other simplified models to accurately describe experimental results. This complicates the study of potentially efficient photocatalytic systems which have not yet been characterized or optimized. The LDA-1/2 is here validated for this class of materials, thus opening the opportunity to study more realistic and complex systems for more accurate calculations, particularly for clean energy generation. In particular, we modeled the structure of TiO2 in the rutile with substitutional nitrogen, whose electronic structure is still debated. It was the first application of the LDA-1/2 systems with some kind of defect, with excellent results for the new system Ti1-_O4N with Ti vacancies.

Submitted by Fernanda Weschenfelder (fernanda.weschenfelder@uniceub.br) on 2018-05-28T18:43:17Z No. of bitstreams: 1 61300067.pdf: 1248300 bytes, checksum: 9d3f40fb51f674713bd598e87a9ae2a5 (MD5) / Approved for entry into archive by Fernanda Weschenfelder (fernanda.weschenfelder@uniceub.br) on 2018-05-28T18:43:22Z (GMT) No. of bitstreams: 1 61300067.pdf: 1248300 bytes, checksum: 9d3f40fb51f674713bd598e87a9ae2a5 (MD5) / Made available in DSpace on 2018-05-28T18:43:22Z (GMT). No. of bitstreams: 1 61300067.pdf: 1248300 bytes, checksum: 9d3f40fb51f674713bd598e87a9ae2a5 (MD5) Previous issue date: 2016 / A presente pesquisa teve como meta avaliar criticamente em que medida os Acordos de Offset contribuem para o desenvolvimento da indústria de defesa, na perspectiva do setor aeronáutico brasileiro. Buscou-se analisar o processo de transferência de tecnologia, a partir dos acordos de compensação firmados no Projeto H-X BR, cujo objeto é a aquisição de 50 helicópteros franceses e suporte logístico inicial, destinados à satisfação de demandas operacionais das três Forças Armadas. A presente pesquisa analisou também as contribuições teóricas das principais linhas de pensamento em relação ao papel da inovação para o segmento de defesa, levando-se em conta os múltiplos participantes da estrutura estatal, a análise do arranjo normativo brasileiro e a natureza jurídica das práticas compensatórias, bem como o papel dos atores envolvidos no processo de aprovação dos Acordos de Offset.

Submitted by Marta Toyoda (1144061@mackenzie.br) on 2018-02-06T19:09:55Z No. of bitstreams: 2 Juliana Alves Luiz Pereira.pdf: 1930409 bytes, checksum: 863dfc773369134ad638c2b866f5868f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Paola Damato (repositorio@mackenzie.br) on 2018-02-22T13:25:42Z (GMT) No. of bitstreams: 2 Juliana Alves Luiz Pereira.pdf: 1930409 bytes, checksum: 863dfc773369134ad638c2b866f5868f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-02-22T13:25:42Z (GMT). No. of bitstreams: 2 Juliana Alves Luiz Pereira.pdf: 1930409 bytes, checksum: 863dfc773369134ad638c2b866f5868f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-11-10 / The purpose of the present study was to intercept the waste ink from offset in ceramic material, as some residues of compensated graphite inks are as hazardous by NBR10004, other toxic materials in its composition, such as lead and antimony. Using factorial planning it was observed that a residue addition did not cause large eyes on the actual porosity and apparent porosity of the sintered ceramics. By means of the results obtained it was observed that at both 1100 ° C and 1200 ° C the test bodies inerted the heavy metals because the metals of the test were not leached according to a standard by the ABNT NBR 10005: 2004 standard. The incorporation of waste into the ceramic mass is economically feasible and socioambiemalmente favorable, because it reduces the cost of the waste of ink to be discarded as well as it avoids its disposal in the environment. / O presente estudo teve o objetivo de intertizar resíduos de tinta offset em material cerâmico, pois alguns resíduos de tintas gráficas offset são considerados como perigosos pela NBR10004, por conter materiais tóxicos em sua composição, como o chumbo e o antimônio. Utilizando planejamento fatorial observou-se que a adição de resíduo não causou grandes alterações na porosidade real e porosidade aparente da cerâmica sinterizada. Por meio dos resultados obtidos observou-se que tanto a 1100°C quanto a 1200°C os corpos de prova inertizaram os metais pesados pois não ocorreu lixiviação dos metais em ensaio segundo a norma pela norma ABNT NBR 10005:2004. A incorporação de resíduo a massa cerâmica é economicamente viável e socio-ambiemtalmente favorável, pois diminui o custo do resíduo de tinta a ser descartado bem como evita seu descarte no meio ambiente.

No description available.

Reducing Emissions from Deforestation and Forest Degradatin (REDD+) is a market-based approachto address tropical deforestation as a key driver of anthropogenic climate change. In Tanzania, participatory forest management (PFM) was used as a vehicle for the institutionalisation of REDD+and implementation of pilot initiatives. With the lens of political ecology, this thesis analyses the effects of the REDD+ pilot project ‘Advancing REDD+ in the Kolo Hills Forests’ (ARKFor) inKondoa District, Tanzania, on structures of access and use of forest resources for local communities. This analysis is done by using qualitative interviews with villagers living within the REDD+ project area and government actors involved in forest management as well as textual analysis of a PFMagreement and community bye-laws established within the ARKFor project. The findings suggest that REDD+ pilot activities were planned without real participation by local communities and failed to take complex conservation histories and underlying power structures into account. Community access rights were not legally secured which resulted in processes of re-centralisation of forest managementand ‘green grabbing’ after the conclusion of project activities in 2014. The study underscores that successful forest management decentralisation needs to be based on localised, longer-term adaptive processes which clash with the globally driven, neoliberal conservation logic of REDD+.

Le marché volontaire du carbone est un mécanisme de marché de compensation d’émissions de gaz à effet de serre pour les entreprises et les particuliers non assujettis à un quota de réduction d’émissions. Jusqu'à présent, il n’a fait l’objet que de peu de recherches académiques. Ce travail s’intéresse à la gouvernance de la chaîne d’acteurs impliqués dans ce marché. Il utilise une approche pluridisciplinaire centrée sur les relations internationales, la science politique appliquée à la compensation et aux standards volontaires environnementaux et s’appuie sur une analyse anthropologique des projets de développement. Il s’agit de répondre à la question: comment les projets de compensation volontaire du carbone sont-ils gouvernés ? L’étude de cas d’un programme de diffusion de foyers améliorés au Pérou se focalise d’abord sur le contexte social et culturel de la cuisson dans les Andes avant d’étudier quatre projets avant financement carbone. Ensuite, le standard utilisé pour certifier ce projet, ainsi que le détaillant des crédits carbone générés par le projet et trois de ses entreprises clientes sont présentés. On peut alors aborder la création, la gestion et les premiers résultats du programme au travers d’une ethnographie de l’entreprise sociale qui en est à l’origine pour comprendre finalement l’influence du projet dans le secteur péruvien. Cette recherche montre un système de gouvernance multi-niveaux et pluri-acteurs majoritairement privée qui agit en grande partie en parallèle de l'État. Ce mode de gouvernance caractérisé par une succession de standards qui tentent de faire coller la réalité à un modèle est appelé standardisme. / The voluntary carbon offset market is a market mechanism for offsetting greenhouse gases emissions for organizations and individuals that are not legally committed to reductions. Until now it has not been studied much in academic circles. This dissertation looks at the governance of the chain of actors involved in the mechanism. A pluri-disciplinary approach is used based on international relations, political science of offsets and standards combined with an anthropological analysis of development projects. The central question is thus: how are carbon-offset programs governed? The empirical work is a case study of a new stove (improved cookstoves) diffusion program in Peru under the Gold Standard. The first focus is on the social and cultural context of cooking in the Andes. Then four projects before carbon funding are studied. The standard is the subject of the following section and the retailer of the credits generated by the programme and three different types of clients are then presented. We can then discuss the creation, design and management of the standard through an ethnography of the social business that implements. Finally, the influence of the projects on the sector can be discussed. The chain studied presents a governance system that is multi-level and multi-actors, with mainly private actors that act parallel to the state. This type of governance is characterized by a series of standards that define the model the reality should resemble to and is called standardism.

Institut de recherche Robert-Sauvé en santé et en sécurité du travail

The rapid progress of scaling and integration of modern complimentary metal oxide semiconductor (CMOS) technology motivates the replacement of traditional analog signal processing by digital alternatives. Thus, analog-to-digital converters (ADCs), as the interfaces between the analog world and the digital one, are driven to enhance their performance in terms of speed, resolution and power efficiency. However, in the presence of imperfections of device mismatch, thermal noise and reduced voltage headroom, efficient ADC design demands new strategies for design, calibration and optimization. Among various ADC architectures, successive-approximation-register (SAR) ADCs have received renewed interest from the design community due to their low hardware complexity and scaling-friendly property. However, the conventional SAR architecture has many limitations for high-speed, high-resolution applications. Many modified SAR architectures and hybrid SAR architectures have been reported to break the inherent constraints in the conventional SAR architecture. Loop-unrolled (LU) SAR ADCs have been recognized as a promising architecture for high-speed applications. However, mismatched comparator offsets introduce input-level dependent errors to the conversion result, which deteriorates the linearity and limits the resolution and the resolution of most reported SAR ADCs of this kind are limited to 6 bits. Also, for high-resolution SAR ADCs, the comparator noise specification is very stringent, which imposes a limitation on ADC speed and power-efficiency. Lastly, capacitor mismatch is an important limiting factor for SAR ADC linearity, and generally requires dedicated calibration to achieve efficient designs in terms of power and area. In this work, we investigate the impacts of offset mismatch, comparator noise and capacitor mismatch on high-speed SAR ADCs. An analytical model is proposed to estimate the resolution and predict the yield of LU-SAR ADCs with presence of comparator offset mismatch. A background calibration technique is proposed for resolving the comparator mismatch issue. A 150-MS/s 8-bit LU-SAR ADC is fabricated in a 130-nm CMOS technology to validate the concept. The measured result shows that the calibration improves the SNDR from 33.7-dB to 42.9-dB. The ADC consumes 640 μW from a 1.2 V supply with a Figure-of-Merit (FoM) of 37.5-fJ/conv-step. Moreover, the bit-wise impact of comparator noise is studied for LU-SAR ADCs. Lastly, an extended statistical element selection (SES) calibration technique is proposed to calibrate the capacitor mismatch in SAR ADCs. Based on these techniques, a high-resolution, asynchronous SAR architecture employing multiple comparators with different speed and noise specifications to optimize speed and power efficiency. A 12-bit prototype ADC is fabricated in a 1P9M 65nm CMOS technology, and fits into an active area of 500 μm × 200 μm. At 125 MS/s, the ADC achieves a signal-to-noise-and-distortion ratio (SNDR) of 64.4 dB and a spurious-free-dynamic-range (SFDR) of 75.1 dB at the Nyquist input frequency while consuming 1.7 mW from a 1.2 V supply. The resultant figure-of-merit (FoM) is 10.3 fJ/conv-step.

No description available.

Výpočetní tomografie je nástroj pro nedestruktivní inspekci vzorků, který je běžně používán v mnoha oblastech průmyslu a výzkumu. Některé tomografické přístroje umožňují snímání obrazů s prostorovým rozlišením pod jeden mikrometr. Zorné pole takovýchto přístrojů bývá malé, v rozsahu jednotek milimetrů či méně. Tím jsou omezeny rozměry vzorků, což je značně limitující. Toto omezení lze překonat pomocí různých technik pro rozšíření zorného pole. Jedna takováto dříve publikovaná metoda byla v této práci upravena a implementována pro přístroj Rigaku Nano3DX. Tato technika téměř zdvojnásobuje zorné pole přístroje bez nutnosti většího detektoru. Implementovaný přístup byl testován pomocí umělých i skutečných dat, a jeho účinnost byla zhodnocena subjektivně i objektivně, pomocí vizuální kontroly a metrik kvality obrazu. Hodnocení je převážně založeno na srovnání obrazů rekonstruovaných pomocí této metody s obrazy získanými pomocí většího detektoru. Implementovaná technika rozšíření zorného pole poskytuje věrné rekonstrukce vzorku, srovnatelné se zmíněnými protějšky.