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Etude des écoulements à l'interface joint-rugosité pour des applications de haute étanchéité / Study of the flow at the seal-flange interface for high performance sealing applicationsZaouter, Tony 19 October 2018 (has links)
Certaines applications industrielles nécessitent des niveaux d’étanchéité exceptionnels pour permettre la réalisation d’un vide poussé ou pour répondre à des enjeux de sécurité radiologique par exemple. Ces niveaux de haute étanchéité statique sur des assemblages démontables sont obtenus à l’aide de joints entièrement métalliques. La fuite résultante de l’assemblage n’est due qu’à la persistance d’un champ des ouvertures à l’interface entre le joint d’étanchéité et la bride d’assemblage, conséquence d’un contact imparfait entre les deux surfaces rugueuses. Le champ des ouvertures à l’interface de contact est assimilable à une fracture rugueuse hétérogène, de nature multi-échelle, et peut en principe être obtenu par un calcul de déformations mécaniques préalable. Dans ce travail, on s’intéressera plus particulièrement à l’écoulement gazeux raréfié dans le régime glissant au sein de cette fracture. Pour les régimes modérément raréfiés,l’écoulement est modélisé par l’équation de Reynolds faiblement compressible avec correction de glissement de premier ordre aux parois que l’on développe. On effectue ensuite un changement d’échelle par la méthode de la prise de moyenne volumique, permettant d’établir un modèle macroscopique d’écoulement à l’échelle d’un élément représentatif, où le débit massique est relié au gradient de pression via le tenseur de transmissivité. Celui-ci, caractéristique de l’élément représentatif de fracture, est calculé par résolution d’un problème de fermeture et est dépendant de la microstructure ainsi que du libre parcours moyen représentatif sur l’élément. Pour remonter à l’écoulement dans l’ensemble de la fracture, hétérogène à cette échelle, celle-ci est subdiviséeen pavés sur chacun desquels est calculé un tenseur de transmissivité local par la méthode sus-citée. Ensuite, l’écoulement dans ce champ de tenseurs est résolu par une méthode des éléments finis de frontière, donnant la transmissivité apparente glissante du joint dans son ensemble. Cette approche à deux échelles, vue comme outil d’aide à la conception, permet une réduction de la complexité de calcul par rapport à une simulation directe, rendant possible une analyse plus efficace du comportement d’un système d’étanchéité. Pour valider l’utilisation du modèle de glissement d’un point de vue macroscopique et s’affranchir des incertitudes sur le calcul de déformation mécanique, des puces nanofluidiques de type réseau hétérogène de canaux droits sont fabriquées par photolithographie par niveaux de gris. Des essais expérimentaux de mesure de fuite sont réalisés sur ces géométries modèles, représentant des joints idéalisés. Ces essais sont effectués en appliquant une forte différence de pression d’hélium par utilisation d’un spectromètre de masse mesurant la fuite, produisant une condition de vide en sortie de puce.Selon les puces, les régimes de raréfaction atteints vont alors du régime glissant au régime moléculaire. Le débit de fuite mesuré est alors supérieur à celui prédit par le modèle de premier ordre, l’écart restant inférieur à un ordre de grandeur quel que soit le régime / Some industrial applications require exceptional sealing levels to maintain ultra-high vacuumconditions or for radiological safety concerns for example. Such high performance static sealingconditions on mechanical assemblies are reached using entirely metallic gaskets. The resultingleak-rate is only due to the persistence of an aperture field at the seal-flange interface,consequence of a non-ideal contact between the two rough surfaces. This aperture field can beviewed as a rough and heterogeneous fracture, of multi-scale nature, and can be obtained by aprior contact mechanics computation. In this work, we are interested on the rarefied flow of a gasin this fracture, drawing our attention to the slip regime. For such moderately rarefied regime, theflow is described by the slightly compressible Reynolds equation with a first-order slip-flowcorrection at the walls, which we develop. Using the method of volume averaging, an upscalingprocedure is performed to derive the macroscopic flow model at the scale of a representativeelement, and where the mass flow rate is related to the pressure gradient by the transmissivitytensor. This latter is characteristic of the representative fracture element and is obtained by solvingan auxiliary closure problem which depends on the micro-structure as well as the representativemean free path on the element. To compute the flow in the whole fracture, heterogeneous at thisscale, it is subdivided in tiles on which a transmissivity tensor is locally computed by theaforementioned method. Then, the flow problem in this tensor field is solved using a boundaryelement method, leading to the apparent slip-corrected transmissivity of the entire aperture field.This two-scale approach is a conception tool which reduces the overall complexity with respect toa direct numerical simulation, allowing a more efficient analysis of the behavior of a sealingassembly. To validate the use of slip models at the macroscopic level and to eliminate theuncertainties of the contact mechanics computation, nanofluidic chips composed ofheterogeneous network of straight channels are fabricated using a grayscale photolithographytechnique. Experimental measurements of the leak-rate are performed on these idealizedgeometries that mimic a seal assembly. They are realized by applying a strong helium pressuredifference on the chip using a mass spectrometer to measure the leak, which produces a nearvacuum condition at the outlet. Depending of the chip, the rarefaction regime ranges from slip tofree-molecular. The measured leak-rate is greater than predicted by the first order model, thoughbeing of the same order of magnitude whatever the regime
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Análise do uso de redundância em circuitos gerados por síntese de alto nível para FPGA programado por SRAM sob falhas transientesSantos, André Flores dos January 2017 (has links)
Este trabalho consiste no estudo e análise da suscetibilidade a efeitos da radiação em projetos de circuitos gerados por ferramenta de Síntese de Alto Nível para FPGAs (Field Programmable Gate Array), ou seja, circuitos programáveis e sistemas em chip, do inglês System-on-Chip (SOC). Através de um injetor de falhas por emulação usando o ICAP (Internal Configuration Access Port) localizado dentro do FPGA é possível injetar falhas simples ou acumuladas do tipo SEU (Single Event Upset), definidas como perturbações que podem afetar o funcionamento correto do dispositivo através da inversão de um bit por uma partícula carregada. SEU está dentro da classificação de SEEs (Single Event Effects), efeitos transitórios em tradução livre, podem ocorrer devido a penetração de partículas de alta energia do espaço e do sol (raios cósmicos e solares) na atmosfera da Terra que colidem com átomos de nitrogênio e oxigênio resultando na produção de partículas carregadas, na grande maioria nêutrons. Dentro deste contexto além de analisar a suscetibilidade de projetos gerados por ferramenta de Síntese de Alto Nível, torna-se relevante o estudo de técnicas de redundância como TMR (Triple Modular Redundance) para detecção, correção de erros e comparação com projetos desprotegidos verificando a confiabilidade. Os resultados mostram que no modo de injeção de falhas simples os projetos com redundância TMR demonstram ser efetivos. Na injeção de falhas acumuladas o projeto com múltiplos canais apresentou melhor confiabilidade do que o projeto desprotegido e com redundância de canal simples, tolerando um maior número de falhas antes de ter seu funcionamento comprometido. / This work consists of the study and analysis of the susceptibility to effects of radiation in circuits projects generated by High Level Synthesis tool for FPGAs Field Programmable Gate Array (FPGAs), that is, system-on-chip (SOC). Through an emulation fault injector using ICAP (Internal Configuration Access Port), located inside the FPGA, it is possible to inject single or accumulated failures of the type SEU (Single Event Upset), defined as disturbances that can affect the correct functioning of the device through the inversion of a bit by a charged particle. SEU is within the classification of SEEs (Single Event Effects), can occur due to the penetration of high energy particles from space and from the sun (cosmic and solar rays) in the Earth's atmosphere that collide with atoms of nitrogen and oxygen resulting in the production of charged particles, most of them neutrons. In this context, in addition to analyzing the susceptibility of projects generated by a High Level Synthesis tool, it becomes relevant to study redundancy techniques such as TMR (Triple Modular Redundancy) for detection, correction of errors and comparison with unprotected projects verifying the reliability. The results show that in the simple fault injection mode TMR redundant projects prove to be effective. In the case of accumulated fault injection, the multichannel design presented better reliability than the unprotected design and with single channel redundancy, tolerating a greater number of failures before its operation was compromised.
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Avaliação ambiental e econômica do processo de limpeza para a reciclagem do cavaco metálico contaminado com fluído de corteSimon, Luísa 30 August 2016 (has links)
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Previous issue date: 2016-08-30 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / CNPQ - Conselho Nacional de Desenvolvimento Científico e Tecnológico / O crescimento populacional e sua dependência de bens materiais têm aumentado a demanda pelo desenvolvimento de novas tecnologias que não utilizam em sua maioria recursos naturais não renováveis. Os processos produtivos geram resíduos e esses podem ser dispostos em aterros apropriados, visando o fluxo linear de produção. Porém, a busca por processos sustentáveis e a redução de custos para disposição de resíduos tem levado os empresários a adotar tecnologias limpas favorecendo a reutilização e reciclagem destes resíduos. Outro enfoque é o seu uso como fonte alternativa para aumentar a ecoeficiência e como um objeto maior, a ecoefetividade, ou seja, reduzir os impactos, aumentando a eficiência econômica e ambiental e desta forma contribuir para a sustentabilidade. Esta pesquisa teve como objetivo avaliar ambiental e economicamente processos de limpeza e reciclagem dos cavacos metálicos contaminados com fluido de corte. Para isso, foram identificadas empresas geradoras deste tipo de resíduo da Região Metropolitana de Porto Alegre licenciadas pela FEPAM e por órgãos ambientais municipal através de questionário. A seguir iniciou-se uma pesquisa exploratória entre as empresas identificadas, das quais realizou-se visita de estudo em oito empresas. A partir das empresas visitadas, foram identificadas e mapeadas 16 rotas cujo percurso se dá entre empresa geradora de cavaco e Prestadores de Serviço Ambiental. Com base nos resultados obtidos foram levantados os aspectos e impactos ambientais dos processos de usinagem, separação, armazenamento e transporte dos cavacos metálicos através de uma planilha de avaliação de aspectos e impactos ambientais. Os resultados obtidos permitiram identificar que os impactos adversos mais significativos são oriundos do consumo de insumos e matéria-prima e do transporte do resíduo até o PSA. A partir da quantificação de emissões de CO2 eq. do transporte pode-se observar que é possível reduzir 48% das emissões em um ano apenas mudando a rota e o PSA que recolhe o material. Em relação a avaliação econômica, realizada pelos cálculos de Valor Presente Líquido e Payback, foi possível concluir que o investimento para limpeza dos cavacos se torna viável para empresas que grande geração deste resíduo. Em caso de pouca geração seria mais viável vende-los para um PSA que faria a limpeza juntamente com os cavacos coletados de outras empresas, aumentando o montante a ser limpo. / Population growth and its dependence on material goods have increased the demand for the development of new technologies that do not use mostly non-renewable natural resources. The production processes generate waste and these must be arranged in appropriate landfills, targeting the linear production flow. However, the search for sustainable processes and reducing waste disposal costs has been taken the entrepreneurs to adopt clean technologies favoring the reuse and recycling of waste. Another approach is its use as an alternative source to increase eco-efficiency and as a larger object, the eco-effectiveness, or reduce the impacts, increasing economic and environmental efficiency and thus contribute to the sustainability. This research aimed to evaluate environmental and economic cleaning processes and recycling of metal chips contaminated with cutting fluid. For this generation firms were identified this type of waste in the metropolitan region of Porto Alegre licensed by FEPAM and municipal environmental agencies through a questionnaire. Then began an exploratory survey of the identified firms, which held study tour in eight firms. From the firms visited were identified and mapped 16 routes whose route is between generator of chip and Environmental Service Providers. Based on the results obtained were raised environmental aspects and impacts of machining processes, separation, storage and transportation of metallic chips through a spreadsheet evaluation of environmental aspects and impacts. The results have identified that the most significant adverse impacts come from the consumption of inputs and raw materials and the waste transport to the ESP. From the measurement of CO2 equivalent emissions. Transport can be seen that it is possible to reduce 48% of the emissions in one year only changing the route and collecting the ESP material. Regarding the economic assessment carried out by calculation of Net Present Value and Payback, it was concluded that the investment for chip cleaning becomes feasible for firms with large generation of this waste. In case of little generation would be more feasible to sell them for an ESP that would make cleaning along with the chips collected from other companies, increasing the amount to be clean.
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Bränsleoptimering av befintliga brikettpannorNilsson, Daniel, Rosenqvist, Fredrik, Blomgren, Erik January 2009 (has links)
Intresset för biobränsleproducerad energi har ökat i takt med att kunderna blivit mer miljömedvetna. På grund av detta har efterfrågan på briketter ökat samtidigt som träindustrin har haft det svårt i en sviktande konjunktur. Därför har ett examensarbete utförts i samarbete med E.ON Värme Sverige AB där undersökningar på bränslebyte i pannor avsedda för torra bränslen till fuktigare, stamvedflis har utfört. För denna undersökning har begränsningar införts på övre och undre effekt i form av uppehållstid och slutförbränningstemperatur. Intervallen är enbart beräknade på stamvedflis med 30 och 40 % fukthalt. Undersökning visar att det går bra att elda stamvedsflis i briketteldade pannor utan att emissionerna ökar så pass mycket att villkoren för anläggningarna överskrids om lasten hålls inom vissa intervall. Det möjliga effektintervallet ökar med minskad fukthalt på bränslet. Undersökningen har visat att det är bränslets kvalitet som är den mest begränsande faktorn. / The interest in bioenergy has increased with increased environmental awareness. The increasing demand on biofuels and the decreasing availability of the rawmaterials for making refined biofuels such as wood briquettes and wood pellets have caused the prices of these biofuels to increase. This report is performed in collaboration with E.ON Värme Sverige AB and its purpose is to investigate the possibilities for a change of fuels in existing boilers designed for refined biofuels, from wood briquettes to wood chips. To be able to calculate a power interval where it would be possible to use wood chips with moisture contents of 30 and 40% by weight respectively, we had to make some assumptions regarding maximum flue gas flow, minimum retention time and the lowest temperature regarding complete combustion of CO. Our calculations show that it is possible to use woodchips with a moisture content of 30 % w/w without any significant problems in all our boilers. When the moisture content is increased to 40 % w/w the interval for possible power output becomes more narrow. The amount of dust that is being emitted from the boilers does not exceed the limits regulated by environmental law, unless the thermal load of the boiler is too high. The single most important factor for a successful change of fuel from wood briquettes to woodchips is that the fuel quality is good.
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Biotreatment of propylene glycol methyl ether acetate (PGMEA) and toluene in air streamsChang, Yu-feng 02 July 2009 (has links)
Biotreatment for air pollution control can generally be categorized as biofilter, bioscrubbing and biotrickling filter systems. Generally, biotreatments could be effective and more economical treatment for containment waste gas if designed and operated properly.
A two stage down-flow biofilter (2.18 m in height and 0.4 m¡Ñ0.4 m in cross-sectional area) was constructed to develop a biofilter packed only with fern chips for the removal of air-borne propylene glycol monomethyl ether acetate (PGMEA). Both stages were packed with fern chips of 0.30 m in height and 0.40 m ¡Ñ0.40 m in cross section. Fern chips could avoid the shortcomings of traditional media, such as compaction, drying, and breakdown, which lead to the performance failure of the biofilters. In addition, the fern chip medium has the following merits: (1) simplicity in composition, (2) low pressure drop for gas flow (< 20 mmH2O m-1), (3) simple in humidification, nutrient addition, pH control, and metabolite removal, (4) economical (USD$ 174 ¡V 385 m-3), and (5) low weight (wet basis around 290 kg m-3). Results indicate that with operation conditions of media moisture content controlled in the range of 50 ¡V 74%, media pH of 6.5 ¡V 8.3, EBRT (empty bed retention time) of 0.27 ¡V 0.4 min, influent PGMEA concentrations of 100 to 750 mg m-3, volumetric organic loading of < 170 g m-3 h-1, and nutrition rates of Urea-N 66.0 g m-3.day-1, KH2PO4-P 13.3 g m-3.day-1 and milk powder 1.0 g m-3 day-1, the fern-chip packed biofilter could achieve an overall PGMEA removal efficacy of around 94%. Instant milk powder or liquid milk was essential to the good and stable performance of the biofilter for PGMEA removal.
An activated sludge aeration basin (20 cm i.d., 140 cm height) equipped with either a coarse air diffuser (a plastic pipe perforated with 56 orifices of 2 mm in diameter) or a fine diffuser (porous plastic type with 100-micrometer pores) was utilized to treat an air-borne hydrophobic VOC (toluene, 700 ¡V 800 mg m-3). The purposes of this study were to test the influences of both MLSS and diffuser type on the VOC removal efficiency. Results show that higher MLSS (mixed liquor suspended solids) such as 10,000 ¡V 40,000 mg L-1 in the mixed liquor did not enhance greatly the transfer and removal of the introduced toluene. Instead, activated sludge basins with a normal MLSS (e.g., 2,000 ¡V 4,000 mg L-1) in the mixed liquor and an efficient gas diffusion system with volumetric VOC transfer coefficient of around 10 ¡V 15 h-1 can be used for the removal of hydrophobic VOCs from the introduced gas. For achieving a removal of over 95% of the introduced toluene or similar hydrophobic VOCs, commercial air diffusers for aerobic biological wastewater treatment basins can be used with a submerged liquid depth of over 0.40 m over the diffusers and an aeration intensity (air flow rate/basin cross-sectional area) of lower than 5.0 m3 m-2 h-1.
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Bränsleoptimering av befintliga brikettpannorNilsson, Daniel, Rosenqvist, Fredrik, Blomgren, Erik January 2009 (has links)
<p>Intresset för biobränsleproducerad energi har ökat i takt med att kunderna blivit mer miljömedvetna. På grund av detta har efterfrågan på briketter ökat samtidigt som träindustrin har haft det svårt i en sviktande konjunktur. Därför har ett examensarbete utförts i samarbete med E.ON Värme Sverige AB där undersökningar på bränslebyte i pannor avsedda för torra bränslen till fuktigare, stamvedflis har utfört.<strong></strong></p><p>För denna undersökning har begränsningar införts på övre och undre effekt i form av uppehållstid och slutförbränningstemperatur. Intervallen är enbart beräknade på stamvedflis med 30 och 40 % fukthalt.</p><p>Undersökning visar att det går bra att elda stamvedsflis i briketteldade pannor utan att emissionerna ökar så pass mycket att villkoren för anläggningarna överskrids om lasten hålls inom vissa intervall. Det möjliga effektintervallet ökar med minskad fukthalt på bränslet.</p><p>Undersökningen har visat att det är bränslets kvalitet som är den mest begränsande faktorn.</p> / <p>The interest in bioenergy has increased with increased environmental awareness. The increasing demand on biofuels and the decreasing availability of the rawmaterials for making refined biofuels such as wood briquettes and wood pellets have caused the prices of these biofuels to increase. This report is performed in collaboration with E.ON Värme Sverige AB and its purpose is to investigate the possibilities for a change of fuels in existing boilers designed for refined biofuels, from wood briquettes to wood chips.</p><p>To be able to calculate a power interval where it would be possible to use wood chips with moisture contents of 30 and 40% by weight respectively, we had to make some assumptions regarding maximum flue gas flow, minimum retention time and the lowest temperature regarding complete combustion of CO.</p><p>Our calculations show that it is possible to use woodchips with a moisture content of 30 % w/w without any significant problems in all our boilers. When the moisture content is increased to 40 % w/w the interval for possible power output becomes more narrow. The amount of dust that is being emitted from the boilers does not exceed the limits regulated by environmental law, unless the thermal load of the boiler is too high.</p><p>The single most important factor for a successful change of fuel from wood briquettes to woodchips is that the fuel quality is good.<strong></strong></p>
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Kernel Methods for Genes and Networks to Study Genome-Wide Associations of Lung Cancer and Rheumatoid ArthritisFreytag, Saskia 08 January 2014 (has links)
No description available.
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Smulkintosios medienos tūrio ir masės tyrimas / Choped wood volume and mass researchMozūras, Vytautas 21 June 2010 (has links)
Darbo objektas – smulkintoji mediena (skiedros, naudojamos šildymo katilinių kūrenimui bei celiuliozės gamybai).
Darbo tikslas – Ištirti smulkintosios medienos, skirtos šildymo katilinių kūrenimui bei celiuliozės gamybai, masės ir tūrio kitimo dėsningumus.
Darbo metodai – Empirinio tyrimo metodas paremtas duomenų rinkimu smulkintąją medieną sveriant, atrenkant mėginius ir juos džiovinant. Statistinis duomenų apdorojimas paremtas vidurkių ir standartinių paklaidų skaičiavimais prie tikimybės (p=0,683). Kiekybinis palyginimas - statistinis duomenų apdorojimas paremtas dispersine ir regresine analize, bei taikant koreliacinius ryšius. Visą empirinę medžiagą sudarė 4950 biokuro smulkintos medienos automašinų imtis, iš kurių buvo imami mėginiai po 200 gramų, taip pat 21 mėginys techninės skiedros.
Darbo rezultatai. Iš surinktų duomenų nustatyta, kad santykinis visų frakcijų smulkintos medienos drėgnis didžiausias yra žiemą (gruodžio – kovo mėnesiais, 49 – 57 %). Pavasarį šiai medienai pradėjus džiūti, drėgmė išgaruoja, vandens kiekis medienoje sumažėja ir drėgnos medienos tankis žemiausias būna birželio – rugsėjo mėnesiais (33 – 48 %). Standartinė drėgnio paklaida atskirais mėnesiais svyruoja nuo 0,5 iki 4 %. Esant tam pačiam drėgniui, medienos masės tūrio vienete priklausomybė nuo metų laiko silpniau išreikšta. Medienos vidutinis tankis žiemą svyruoja nuo 810 iki 1200 kg/m³, vasarą nuo 640 iki 850 kg/³. Didėjant medienos santykiniam drėgniui, medienos masė tūrio vienete taip... [toliau žr. visą tekstą] / Work study – Choped wood (chips) The aim of the work: – investigate chopped wood for the heating of local heating stations, also technological chips in cellulose manufacturing, consistent patterns of mass and volume changing. Methods of work: empirical investigation method is based on collecting data by scaling chopped wood, sorting out samples and drying them. Statistical data trimming is based on the calculating of averages and standard error near the probability (p = 0.683). Quantitative comparison – statistical data trimming is based on dispersion and regression analysis as well as applying correlations. All empirical material was made from the sample of 4950 chopped wood bio-fuel auto-cars, from which were taken samples of 200 grams, and 21 sample of technical chips. The results of the work: The data from the samples indicate that the comparative humidity of choped wood reaches it‘s maximum at winter time. The humidity declines in spring time and it reaches the lowest point in the period of june and september. It was estimated that the mass of choped wood differs even if the humidity remains the same and is clearly expressed according to the time of year – it becomes heavier at winter time and lighter in summer.
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Análise do uso de redundância em circuitos gerados por síntese de alto nível para FPGA programado por SRAM sob falhas transientesSantos, André Flores dos January 2017 (has links)
Este trabalho consiste no estudo e análise da suscetibilidade a efeitos da radiação em projetos de circuitos gerados por ferramenta de Síntese de Alto Nível para FPGAs (Field Programmable Gate Array), ou seja, circuitos programáveis e sistemas em chip, do inglês System-on-Chip (SOC). Através de um injetor de falhas por emulação usando o ICAP (Internal Configuration Access Port) localizado dentro do FPGA é possível injetar falhas simples ou acumuladas do tipo SEU (Single Event Upset), definidas como perturbações que podem afetar o funcionamento correto do dispositivo através da inversão de um bit por uma partícula carregada. SEU está dentro da classificação de SEEs (Single Event Effects), efeitos transitórios em tradução livre, podem ocorrer devido a penetração de partículas de alta energia do espaço e do sol (raios cósmicos e solares) na atmosfera da Terra que colidem com átomos de nitrogênio e oxigênio resultando na produção de partículas carregadas, na grande maioria nêutrons. Dentro deste contexto além de analisar a suscetibilidade de projetos gerados por ferramenta de Síntese de Alto Nível, torna-se relevante o estudo de técnicas de redundância como TMR (Triple Modular Redundance) para detecção, correção de erros e comparação com projetos desprotegidos verificando a confiabilidade. Os resultados mostram que no modo de injeção de falhas simples os projetos com redundância TMR demonstram ser efetivos. Na injeção de falhas acumuladas o projeto com múltiplos canais apresentou melhor confiabilidade do que o projeto desprotegido e com redundância de canal simples, tolerando um maior número de falhas antes de ter seu funcionamento comprometido. / This work consists of the study and analysis of the susceptibility to effects of radiation in circuits projects generated by High Level Synthesis tool for FPGAs Field Programmable Gate Array (FPGAs), that is, system-on-chip (SOC). Through an emulation fault injector using ICAP (Internal Configuration Access Port), located inside the FPGA, it is possible to inject single or accumulated failures of the type SEU (Single Event Upset), defined as disturbances that can affect the correct functioning of the device through the inversion of a bit by a charged particle. SEU is within the classification of SEEs (Single Event Effects), can occur due to the penetration of high energy particles from space and from the sun (cosmic and solar rays) in the Earth's atmosphere that collide with atoms of nitrogen and oxygen resulting in the production of charged particles, most of them neutrons. In this context, in addition to analyzing the susceptibility of projects generated by a High Level Synthesis tool, it becomes relevant to study redundancy techniques such as TMR (Triple Modular Redundancy) for detection, correction of errors and comparison with unprotected projects verifying the reliability. The results show that in the simple fault injection mode TMR redundant projects prove to be effective. In the case of accumulated fault injection, the multichannel design presented better reliability than the unprotected design and with single channel redundancy, tolerating a greater number of failures before its operation was compromised.
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Análise do uso de redundância em circuitos gerados por síntese de alto nível para FPGA programado por SRAM sob falhas transientesSantos, André Flores dos January 2017 (has links)
Este trabalho consiste no estudo e análise da suscetibilidade a efeitos da radiação em projetos de circuitos gerados por ferramenta de Síntese de Alto Nível para FPGAs (Field Programmable Gate Array), ou seja, circuitos programáveis e sistemas em chip, do inglês System-on-Chip (SOC). Através de um injetor de falhas por emulação usando o ICAP (Internal Configuration Access Port) localizado dentro do FPGA é possível injetar falhas simples ou acumuladas do tipo SEU (Single Event Upset), definidas como perturbações que podem afetar o funcionamento correto do dispositivo através da inversão de um bit por uma partícula carregada. SEU está dentro da classificação de SEEs (Single Event Effects), efeitos transitórios em tradução livre, podem ocorrer devido a penetração de partículas de alta energia do espaço e do sol (raios cósmicos e solares) na atmosfera da Terra que colidem com átomos de nitrogênio e oxigênio resultando na produção de partículas carregadas, na grande maioria nêutrons. Dentro deste contexto além de analisar a suscetibilidade de projetos gerados por ferramenta de Síntese de Alto Nível, torna-se relevante o estudo de técnicas de redundância como TMR (Triple Modular Redundance) para detecção, correção de erros e comparação com projetos desprotegidos verificando a confiabilidade. Os resultados mostram que no modo de injeção de falhas simples os projetos com redundância TMR demonstram ser efetivos. Na injeção de falhas acumuladas o projeto com múltiplos canais apresentou melhor confiabilidade do que o projeto desprotegido e com redundância de canal simples, tolerando um maior número de falhas antes de ter seu funcionamento comprometido. / This work consists of the study and analysis of the susceptibility to effects of radiation in circuits projects generated by High Level Synthesis tool for FPGAs Field Programmable Gate Array (FPGAs), that is, system-on-chip (SOC). Through an emulation fault injector using ICAP (Internal Configuration Access Port), located inside the FPGA, it is possible to inject single or accumulated failures of the type SEU (Single Event Upset), defined as disturbances that can affect the correct functioning of the device through the inversion of a bit by a charged particle. SEU is within the classification of SEEs (Single Event Effects), can occur due to the penetration of high energy particles from space and from the sun (cosmic and solar rays) in the Earth's atmosphere that collide with atoms of nitrogen and oxygen resulting in the production of charged particles, most of them neutrons. In this context, in addition to analyzing the susceptibility of projects generated by a High Level Synthesis tool, it becomes relevant to study redundancy techniques such as TMR (Triple Modular Redundancy) for detection, correction of errors and comparison with unprotected projects verifying the reliability. The results show that in the simple fault injection mode TMR redundant projects prove to be effective. In the case of accumulated fault injection, the multichannel design presented better reliability than the unprotected design and with single channel redundancy, tolerating a greater number of failures before its operation was compromised.
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