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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Aplica??o de argilas modificadas no abrandamento de ?guas duras

Lima, Roberto Rodrigues Cunha 03 March 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-04-17T21:26:31Z No. of bitstreams: 1 RobertoRodriguesCunhaLima_TESE.pdf: 7306887 bytes, checksum: 2d3570ac4799b41660ad1adcdc1842e7 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-04-18T21:54:32Z (GMT) No. of bitstreams: 1 RobertoRodriguesCunhaLima_TESE.pdf: 7306887 bytes, checksum: 2d3570ac4799b41660ad1adcdc1842e7 (MD5) / Made available in DSpace on 2017-04-18T21:54:32Z (GMT). No. of bitstreams: 1 RobertoRodriguesCunhaLima_TESE.pdf: 7306887 bytes, checksum: 2d3570ac4799b41660ad1adcdc1842e7 (MD5) Previous issue date: 2017-03-03 / A necessidade de diversifica??o das formas de tratamento da ?gua de diferentes fontes e para fins diversos revela-se mais urgente a cada dia, sobretudo quando s?o considerados os impactos econ?micos e sociais associados ao manejo de um recurso natural insubstitu?vel. As argilas podem ser aplicadas no abrandamento de ?guas duras, ampliando as perspectivas de aproveitamento e reuso de ?guas, com o desenvolvimento de dispositivos e processos tecnol?gicos sustent?veis. Neste estudo, al?m das que foram mantidas sem tratamento, amostras de bentonita foram ativadas com HCl e H2SO4, enquanto amostras de vermiculita foram modificadas com HCl, NaOH e NaCl, para ensaios de adsor??o de ?ons Ca2+ utilizando solu??o padr?o de c?lcio e ?guas duras reais coletadas adequadamente de po?os da regi?o central do estado do Rio Grande do Norte, Brasil. Uma redu??o de 22,8 % na dureza da solu??o padr?o de c?lcio foi verificada com bentonita ativada com H2SO4, enquanto efici?ncia mais elevada foi comprovada com vermiculitas tratadas com HCl, NaOH e NaCl, com redu??es nas durezas da solu??o padr?o de c?lcio de 43,6 %, 46,3 % e 57,5 %, respectivamente, e redu??o de at? 45,2 % na dureza de amostra real, com a vermiculita modificada com NaCl, que gerou os melhores resultados. Foi comprovado que ? poss?vel recondicionar a vermiculita, bem como atestar que a concentra??o do eletr?lito e tratamento sucessivo influenciam na capacidade adsortiva dessa argila modificada com NaCl. O tratamento salino da vermiculita pode ser feito, de forma simult?nea, com uma combina??o de Na+ e K+ como c?tions troc?veis. As modifica??es realizadas nas argilas foram rastreadas com an?lises de DRX, MEV, TG, DTG, EDX, BET e medida de par?metros f?sico-qu?micos. Novas pesquisas devem ser estimuladas para o refinamento de t?cnicas e m?todos que apliquem argilas na recupera??o e gerenciamento dos recursos h?dricos. / The need to diversify the ways of treating water from different sources and for different purposes becomes more urgent every day, especially when considering the economic and social impacts associated with management of an irreplaceable natural resource. Clays can be applied for softening hard water, expanding perspectives of water use, with the development of sustainable technological devices and processes. In this study, in addition to those that were kept untreated, bentonite samples were activated with HCl and H2SO4, while vermiculite samples were modified with HCl, NaOH and NaCl, for adsorption tests of Ca2+ ions using standard calcium solution and real hard water adequately collected from wells in the central region of the state of Rio Grande do Norte, Brazil. A reduction of 22.8% in the hardness of the standard calcium solution was verified with H2SO4-activated bentonite, while higher efficiency was verified with vermiculites treated with HCl, NaOH and NaCl, with hardness reductions on the standard calcium solution of 43.6%, 46.3% and 57.5%, respectively, and reduction of up to 45.2% in the hardness of the field-collected samples, with NaCl-modified vermiculite, which generated the best results. It has been proven that it is possible to recondition the vermiculite, and that electrolyte concentration and successive treatment influence the adsorptive capacity of this NaCl-modified clay. Vermiculite saline treatment can be performed simultaneously with a combination of Na+ and K+ as exchangeable cations. Clay modifications were tracked with XRD, SEM, TG, DTG, EDX and BET analyzes, as well as the determination of physicochemical parameters.
22

A dura??o razo?vel do processo na justi?a do trabalho: uma abordagem constitucional

Teixeira, Winston de Ara?jo 06 September 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-11-01T22:40:28Z No. of bitstreams: 1 WinstonDeAraujoTeixeira_DISSERT.pdf: 1204463 bytes, checksum: ce6f9db56353b5a238b14f5f7b448a3a (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-11-14T00:33:03Z (GMT) No. of bitstreams: 1 WinstonDeAraujoTeixeira_DISSERT.pdf: 1204463 bytes, checksum: ce6f9db56353b5a238b14f5f7b448a3a (MD5) / Made available in DSpace on 2017-11-14T00:33:03Z (GMT). No. of bitstreams: 1 WinstonDeAraujoTeixeira_DISSERT.pdf: 1204463 bytes, checksum: ce6f9db56353b5a238b14f5f7b448a3a (MD5) Previous issue date: 2017-09-06 / A presente disserta??o trata da dura??o razo?vel do processo, especificamente, na justi?a do trabalho. Nesse contexto, abordam-se as quest?es constitucionais referentes ? problematiza??o da dura??o razo?vel do processo, enquanto direito fundamental, bem como sua aplicabilidade na justi?a trabalhista. O estudo do tema escolhido ? importante porque traz a discuss?o acerca da ?demora? na presta??o jurisdicional, notadamente, ?quela que assegura os direitos fundamentais dos trabalhadores, proporcionando a an?lise das causas e consequ?ncias do tempo do processo. O presente trabalho tem por objetivo desenvolver uma abordagem constitucional da dura??o razo?vel do processo na justi?a do trabalho, considerando o tempo razo?vel do processo no ordenamento jur?dico brasileiro como um direito fundamental. Levantando a problem?tica dos efeitos do tempo na atividade jurisdicional e o crescente fen?meno da sumariza??o da cogni??o processual, em que o processo de amplo conhecimento come?a a ser visto como uma via residual para solu??o de conflitos. Empregando a t?cnica da documenta??o indireta, atrav?s de pesquisa bibliogr?fica, analisa-se a concep??o de tempo razo?vel do processo adequada ao processo p?trio; a rela??o entre efic?cia, efetividade, seguran?a jur?dica e o tempo razo?vel da presta??o jurisdicional; a positiva??o formal da dura??o razo?vel do processo na Constitui??o Federal de 1988, no direito internacional e em alguns pa?ses latinoamericanos; e a aplicabilidade imediata desse direito fundamental. Desenvolve-se o tema com base no vi?s constitucional de interpreta??o de direitos fundamentais e na principiologia constitucional, abordagem que ter? sempre presente a preocupa??o de pautar-se numa metodologia que contemple os campos normativo, emp?rico-dogm?tico e de concretiza??o do direito fundamental ao tempo razo?vel do processo. Adota-se como corte metodol?gico o estudo dessa problem?tica no ?mbito judicial, mais especificamente, no campo do processo trabalhista. S?o indicadas a crise do Judici?rio e a demora processual como problemas relacionados diretamente aos limites e possibilidades de concretiza??o do direito fundamental em estudo. Por fim, numa vis?o anal?tica e cr?tica, apresenta-se as conclus?es, as quais demonstram as alternativas e/ou mecanismos que podem ser utilizados na supera??o dos limites impostos ? concretiza??o imediata do direito fundamental ao tempo razo?vel do processo na justi?a do trabalho. / The present dissertation deals with the reasonable length of the process, specifically, in labor justice. In this context, we address the constitutional issues regarding the problematization of the reasonable duration of the process, as a fundamental right, as well as its applicability in labor justice. The study of the chosen topic is important because it brings the discussion about the "delay" in the jurisdictional provision, notably to the one that assures the fundamental rights of the workers, providing the analysis of the causes and consequences of the time of the process. The present work aims to develop a constitutional approach to the reasonable length of the process in labor justice, considering the reasonable time of the process in the Brazilian legal system as a fundamental right. The problem of the effects of time on the jurisdictional activity and the growing phenomenon of the summarization of procedural cognition, where the process of extensive knowledge begins to be seen as a residual way to solve conflicts. Using the technique of indirect documentation, through a bibliographical research, the design of reasonable time of the process appropriate to the process of the country is analyzed; the relationship between efficacy, effectiveness, legal certainty and the reasonable time of judicial service; the formal validation of the reasonable duration of the process in the Federal Constitution of 1988, in international law and in some Latin American countries; and the immediate applicability of this fundamental right. The theme is developed based on the constitutional bias of fundamental rights interpretation and constitutional principles, an approach that will always have the concern of being guided by a methodology that contemplates normative, empirical-dogmatic and fundamental right to time process. The study of this problematic in the judicial scope, more specifically, in the field of the labor process, is adopted as methodological section. The crisis of the Judiciary and procedural delays are indicated as problems directly related to the limits and possibilities of realization of the fundamental right under study. Finally, in an analytical and critical view, the conclusions are presented, which demonstrate the alternatives and / or mechanisms that can be used in overcoming the limits imposed to the immediate realization of the fundamental right to the reasonable time of the process in the labor courts.
23

Pagan Roman Religious Acculturation? An Inquiry into the Domestic Cult at Karanis, Ephesos and Dura-Europos: The First to Fifth Centuries CE

Yandek, Amy C. January 2013 (has links)
The ancient Roman domestic cult is often overlooked and marginalized in favor of state sponsored practices, monuments, and temples; yet it can give us insights into daily life, cultural interactions, and personal identity in the Empire. In my dissertation, I recreate a selection of domestic contexts in order to learn more about private cultic practices, thus illuminating those activities and behaviors that may be far removed from what appears in the literary sources or in monumental reliefs and paintings. Furthermore, the era considered is a crucial period in the history of the western world that included the rise of Christianity and dramatic changes in Roman pagan cults. By concentrating on the Roman East, I produce information relating to these changes outside of Italy and study the impact on cross-cultural exchanges and identities formulated by the Roman colonization of these cities. The Roman domestic cult in Italy invoked specific gods to maintain the well-being of the home in small shrines within the house. Material evidence for these practices survives in the form of statuettes and wall paintings of the gods, incense burners, and altars. Other divinities chosen by the head of the household could join or supplant the traditional domestic deities. These additions to private shrines acted as protective patron gods of the household and they reveal a personal relationship between deity and devotee. One barrier to the understanding of the domestic cult in its original context is the nature of multiculturalism in the Roman Empire. In the nineteenth and early twentieth centuries, scholars tended to equate the Roman Empire with the concept of the modern nation-state. The Empire was seen as a cultural juggernaut that disseminated a uniform Roman identity that was sent out from Italy to the provinces. Evidence for "Romanization" was noted in the introduction of the Roman city plan, and Roman habits were seen in new types of public buildings such as baths or amphitheaters, the adoption of Roman coinage, the toga and the Latin language, and the introduction of Roman cults, especially the cult of the emperor. Most scholars today prefer to view the expansion of the Empire as a process that included reciprocal acculturation between natives and their Roman masters. Using this model, I examine religious cross-currents on a domestic scale, thus contributing to the current scholarly discussion. By exploring the cult in the home, we can get a better indication of the interaction between native and Roman in the private sphere. Scholars agree that we can learn more from smaller, regional studies; it cannot be assumed that the same things occurred in all parts of the empire and at all times. The case-study approach has replaced the sweeping and sometimes vague histories of years past. I have chosen three sites from the Roman East since they have an abundance of material evidence that has not been exploited to its full potential: Karanis (modern Egypt), Ephesos (modern Turkey), and Dura-Europos (modern Syria). The significance of my project is three-fold. I present previously unpublished material from important sites in the Roman East. By looking at these three sites, I expand the dialogue from the singular discussion of domestic religion in first-century Italy, thus enriching it substantially. Through the consideration of acculturation between east and west I contribute to the discussion of "Romanization" in the first to fifth centuries CE. By comparing these sites with those better published, such as Pompeii and Ostia (Rome's port, largely abandoned in the second half of the third into the fourth centuries), I can more clearly show the contrast between the two halves of the Empire. My goals will be to determine how (and if) "Romanization" can be seen in these locations, what the impact of local artistic styles and indigenous deities is, and how the reciprocal relationship manifests in daily religious practices within the home. / Art History
24

A comparative study on the functionality of porcine dura as a tissue-engineered dura mater graft for clinical applications

Sharma, Ashma 13 May 2022 (has links) (PDF)
Damage to dura mater may occur during intracranial or spinal surgeries, which can result in cerebrospinal fluid leakage as well as other potentially fatal physiological changes. As a result, biological scaffolds derived from xenogeneic materials are typically used to repair and regenerate dura mater post intracranial or spinal surgeries. In this study we explore the mechanics, structure, and immunological capacity of xenogeneic dura mater to be considered as a replacement for human dura. A comparative analysis is done between native porcine dura and a commercially available bovine collagen-based dura graft. Native porcine dura mater was decellularized and subjected to mechanical and histological analysis. Our decellularized porcine dura was able to maintain the overall morphological/structural integrity and held an increased extensibility without sacrificing strength, which provides a solid foundation as a functional grafting material. The histological observations showed that the orientation of fibers was maintained after decellularization. We investigated the biocompatibility of native and decellularized porcine dura reseeded with fibroblast cells for in vitro study. Cell proliferation, cell viability, and mechanical properties of dural grafts were evaluated post reseeding on days 3, 7, and 14. Live-dead staining and resazurin salts quantified cell viability and cell proliferation, respectively. This in vitro study showed that the acellular porcine dural graft provided a favorable environment for rat fibroblast cell infiltration. The results of micro indentation testing show that the cell-seeded porcine dural graft provides a favorable environment for rat fibroblast cell infiltration. The mechanics and biocompatibility results provide promising insight for the potential use of porcine dura in future cranial dura mater graft applications. Lastly, a subcutaneous in vivo study of dura graft compared with the market available Lyoplant®. Grafts were evaluated for inflammation by evaluating macrophage and leukocyte invasion on 3, 7, and 14 days post implantation. Histological analysis of both implants revealed macrophage (and leukocyte infiltration, supporting reabsorption, and thus encouraging the regeneration at 14 days. Cell markers also revealed that inflammation and leukocytes decreased as the number of days increased. Future work will involve a long-term subcutaneous implantation up to 30 days and 60 days to determine the long-term immune response.
25

Ozbrojené násilí - gangy maras - výzva a hrozba pro národní stát. Příklad El Salvadoru, Guatemaly a Hondurasu / Armed Violence - Gangs Maras - Challenge and Threat to the National State in El Salvador, Guatemala and Honduras

Líčková, Kateřina January 2011 (has links)
The three countries of Central America El Salvador, Guatemala and Honduras, which form the so-called Northern Triangle, are among the most violent countries in the world. One of the actors of local violence are gangs maras. This thesis "Armed Violence - Gangs Maras - Challenge and Threat to the National State in El Salvador, Guatemala and Honduras." deals with the problem of transnational gangs Mara Salvatrucha (MS- 13) and Barrio 18 (M-18) and with the interaction between maras and society. The aim of this thesis is to understand the complexity of the maras phenomen and to provide its detailed analysis. Maras were originally founded in Los Angeles by Mexican (M-18) and Salvadorian (MS-13) immigrants. As a result of tighter U.S. immigration policy, some members were deported to their country of origin - to the northern triangle countries. The strong cultural identity of maras appealed to thousands of young people and helped in the rapid expansion of the gangs. Maras are currently regarded as one of the greatest threats to the Central American region. Since 2003 the governments have led a repressive campaign to combat maras, which is supported by media and which sought to involve military in police actions. However, the politics of firm hand haven't had desired effect. Labeling maras as the main...
26

Avaliação de marcadores moleculares associados à qualidade da carne de bovinos Simental Sul Africano x Nelore / Evaluation of molecular markers associated with meat quality in crossbreed South African Simmental x Nellore

Fonseca, Roberta Doriguello 07 October 2016 (has links)
No Brasil, a perspectiva de aumento do volume de exportações e a exigência dos diferentes mercados faz com que a adaptação da cadeia produtiva da carne seja necessária, assim como a mudança de conceitos e critérios de seleção dos animais, de forma a melhorar as características consideradas pelo consumidor como de primeira importância: aparência e a palatabilidade. Porém existem diversos fatores que podem influenciar na qualidade da carne: sexo, raça (genética), idade, nutrição e estresse durante a vida do animal. Esses fatores influenciam diretamente no produto final, pois têm relação com as mudanças que ocorrem durante o post mortem. Desta forma, este trabalho teve como objetivo geral avaliar a influencia do pH, da condição sexual e de polimorfismos genéticos em genes relacionados à qualidade da carne e a resposta ao estresse sobre a variação das características da carne em rebanho bovino comercial Simental Sul Africano x Nelore. Para isso o trabalho foi dividido em duas partes: (a) avaliar os parâmetros de qualidade da carne em dois diferentes tempos de maturação (48 horas e 15 dias), sendo estudadas as variações entre os sexos (fêmeas e machos castrados), e nos diferentes valores de pH (classe 1=pH ≤ 5,79 e classe 2=pH ≥ 5,8). (b) Associar SNPs de diferentes genes ou marcadores (CAPN, UOGCAST, NR3C1_1, NR3C2_1, TG5) ligados a características de qualidade da carne, visando compreender melhor os efeitos genéticos desses marcadores sobre as características da carne. Para esta pesquisa foram avaliados 485 bovinos (182 fêmeas e 303 machos) recriados e terminados em confinamento. Os resultados mostraram haver relação do sexo como parâmetros de cor e maciez. As classes de pH mostraram relação significativa com a cor da carne. Verificou-se incidência de carnes DFD (pH≥5,8) da ordem de 5,3%. Dos polimorfismos estudados foram encontradas associações significativas apenas para CAPN, NR3C1_1 e TG. O CAPN relacionado à cor e, NR3C1_1 e TG com as perdas de água por cocção (PAC). Portanto, é possível inferir que tanto o sexo quanto as classes de pH tem influencia direta com os parâmetros de qualidade da carne. Os polimorfismos dos genes CAPN, NR3C1_1 e TG propiciaram mudanças nas características físico-químicas da carne. / In Brazil, the prospect of increased exports and the requirement of different markets makes necessary adaptation of the meat production chain, as the change of concepts and criteria in animal selection to improve the characteristics that the consumer consider as most important: appearance and palatability. However, there are some factors that could influence meat quality: sex, breed (genetics), age, nutrition and stress during the life of the animal. These factors directly influence the final product, since they are related to changes that occur during post mortem period. The aim was to evaluate the pH influence, sexual condition and genetic polymorphisms on genes related to meat quality and stress response on meat quality variation of South African Simmental x Nellore beef cattle. Therefore, this research were divided into two parts: (a) to evaluate the meat quality characteristics in two different aging times (2 and 15 days), being studied variations within the sexual condition (females and castrated males), as well as within the pH range (pH ≤ 5.79 Class 1 and Class 2 ≥ pH 5.8). (b) Associate SNPs of different genes (CAPN, UOGCAST, NR3C1_1, NR3C2_1, TG5) with meat quality characteristics. For this research were evaluated 485 animals (182 heifers and 303 steers) recreated and finished in feedlot. The results shows relation of sex with color and tenderness and, from pH range with color. There was an incidence of DFD meat (pH≥5,8) of 5,3%. The CAPN polymorphism was associated with color meat and NR3C1_1 and TG with cooking loss. Therefore, it is possible to infer that both sex and pH value influence in the meat quality. The polymorphisms CAPN, NR3C1_1 and TG led to changes in the physicochemical characteristics of the meat.
27

Efeito do tamanho do abrasivo no desgaste de metais. / The effect of abrasive size on the wear resistance of metallic materials.

Coronado Marin, John Jairo 08 June 2010 (has links)
Neste trabalho, foi investigado o efeito do tamanho do abrasivo na resistência ao desgaste de cinco ligas metálicas. Foi usado, para este estudo, o equipamento pino contra lixa e alumina como abrasivo, com tamanho médio entre 16 µm e 192 µm. A microestrutura das ligas metálicas foi caracterizada com microscopia ótica e os mecanismos de desgaste abrasivo e os microcavacos (partículas de desgaste) foram caracterizados usando microscopia eletrônica de varredura (MEV). Em uma primeira série de experimentos, foi usado ferro fundido mesclado com carbonetos M3C (temperado e revenido a temperaturas entre 300 e 600°C). Para abrasivos pequenos, a perda de massa elevou-se com o aumento do tamanho do abrasivo. Entretanto, para abrasivos grandes, a perda de massa aumenta com inclinação menor e o mecanismo prevalente de desgaste é o microcorte. Para abrasivos maiores, o mecanismo prevalente de desgaste é microsulcamento. Em uma segunda série de experimentos, foi usado ferro fundido branco (FFB), com matrizes austenítica e martensítica. O FFB com matriz austenítica apresentou um tamanho crítico de abrasivo (TCA) de 36 µm e, para o ferro fundido martensítico, foi aproximadamente de 116 µm. A perda de massa do ferro fundido com matriz austenítica aumentou linearmente com o aumento do tamanho dos abrasivos, após o TCA a perda de massa aumenta com inclinação menor. O FFB martensítico, com menores tamanhos do abrasivo, apresentou um comportamento linear. Existe, porém, uma região de transição não-linear e achatada, quando o tamanho de partícula crítico é atingido, tornando-se independente do tamanho do abrasivo. Antes do TCA, o micromecanismo prevalente de desgaste foi microcorte e a lixa apresentou cavacos contínuos e finos e, após o TCA, o mecanismo prevalente de desgaste foi microsulcamento e apresentou cavacos descontínuos e deformados. O efeito do tamanho de abrasivo observado na perda de massa foi apresentado na energia especifica de corte e no coeficiente de atrito. Em uma terceira série de experimentos, foi usado alumínio e aço AISI 1045. O alumínio (estrutura cristalina cúbica de fase centrada) apresentou um comportamento similar ao observado no FFB com matriz austenítica, e o aço AISI 1045 apresentou um comportamento similar ao FFB com matriz martensítica. Verificou-se que, no alumínio e no aço AISI 1045, também se apresenta mudança na morfologia dos cavacos e nos micromecanismos de desgaste, observados nos materiais com segunda fase dura. Em uma quarta série de experimentos, foi usado o ferro fundido cinzento para corroborar a mudança dos micromecanismos de desgaste abrasivo e dos microcavacos com o TCA. O ferro fundido cinzento não apresentou uma transição (TCA) na curva de tamanho de abrasivo contra perda de massa. A morfologia dos cavacos foi similar para os diferentes tamanhos de abrasivos (descontínua). Para abrasivos menores, porém, apresentaram-se alguns cavacos contínuos e finos. O micromecanismo prevalente de desgaste abrasivo foi de microcorte para os diferentes abrasivos usados. Portanto, nesta pesquisa, foi demonstrado que o tamanho crítico de abrasivo está relacionado com os micromecanismos de desgaste e com a morfologia dos microcavacos. / In this research, the effect of abrasive size on the wear resistance of five metallic materials was investigated. Abrasive wear tests using a pin test on alumina paper were carried out using abrasive sizes between 16 µm and 192 µm. The wear surface of the specimens was examined by scanning electron microscopy for identifying the wear micromechanism and the type of microchips formed on the abrasive paper (wear debris). In a first series of experiments mottled cast iron samples with M 3 C carbides were tested. The samples were quenched and tempered in temperatures ranging from 300°C to 600°C. For small abrasive particles, the wear mass loss increased linearly with the increase of particle size. However, for higher abrasive sizes the wear mass loss increased much more slowly. For lower abrasive sizes the main wear mechanism was microcutting. For higher abrasive sizes, the main wear mechanism was microploughing. In a second series of experiments white cast iron with M 3 C carbide with austenitic and martensitic matrix were tested. The results show that the mass loss for cast irons with austenitic and martensitic matrices increases linearly with the increase of particle size until the critical particle size is reached. The cast iron with austenitic matrix presented a critical abrasive size of 36 µm and for the martensitic cast iron, the critical particle size was about 116 µm. After the critical particle size is reached, the rate of mass loss of the cast iron with austenitic matrix diminishes to a lower linear rate, and for cast irons with martensitic matrix the curve of mass loss is non-linear and flattens when the critical particle size is reached. It becomes, then, constant, independent of additional size increases. The abrasive paper in contact with the iron of both austenitic and martensitic matrices presents fine continuous microchips and the main wear mechanism was microcutting before reaching critical particle size, and after that it presents deformed discontinuous microchips and the main wear mechanism was microploughing. This behavior of change in rates after reaching a critical size happened not only for mass loss versus abrasive size, but it was also observed both in curves of friction coefficient and specific cutting energy versus abrasive size. In a third series of experiments aluminum and AISI 1045 steel were tested. The first (FCC structure) showed similar behavior to that observed in the white cast iron with austenitic matrix and the latter showed similar behavior to that observed in white cast iron with martensitic matrix. Both aluminum and AISI 1045 steel show similar changes in the microchips morphology and in the wear micromechanisms, something that had been observed before in materials with hard second phase. In a fourth series of experiments gray cast iron was tested in order to demonstrate the relationship between the abrasive wear micromechanisms and the type of microchips, before and after achieving critical abrasive size. The grey cast iron did not show a transition in the curve of abrasive size against mass loss. The morphology of the chips was similar for the different sizes of abrasive (discontinuous). However, smaller abrasive sizes some thin continuous microchips were formed. The main abrasive wear micromechanism was microcutting for the different abrasives sizes tested. Therefore, it was shown that the critical abrasive size is related to the wear micromechanisms and the microchips morphology.
28

Contratos empresariais de longa dura??o e incompletude contratual

Faganello, Tiago 21 February 2017 (has links)
Submitted by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-07-31T11:45:36Z No. of bitstreams: 1 DIS_TIAGO_FAGANELLO_PARCIAL.pdf: 377919 bytes, checksum: c7b4be1f8100a5e74e1de397c5148a29 (MD5) / Approved for entry into archive by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-07-31T11:45:46Z (GMT) No. of bitstreams: 1 DIS_TIAGO_FAGANELLO_PARCIAL.pdf: 377919 bytes, checksum: c7b4be1f8100a5e74e1de397c5148a29 (MD5) / Made available in DSpace on 2017-07-31T11:45:54Z (GMT). No. of bitstreams: 1 DIS_TIAGO_FAGANELLO_PARCIAL.pdf: 377919 bytes, checksum: c7b4be1f8100a5e74e1de397c5148a29 (MD5) Previous issue date: 2017-02-21 / The present dissertation has the objective of analyzing long-term commercial contracts that have contractual gaps (lacunae), especially through the literature of Law and Economics. In scenarios of perfect competition, contracts would be able to foresee all contingencies and perfect state of nature. However, real markets do not reflect the perfect competition model and, as such, as there may be gap in the legal system (article 4 of the Law of Introduction to Brazilian Law), there are situations in which there may be gap in the contract drafted by the parties to serve a particular purpose. Contracts that contain such lacunae are known as incomplete contracts, and these omissions may be voluntary or involuntary. Thus, initially, the first part of this dissertation will establish a general framework of contracts and their relations to the economy and the market. Following, the concept of long-term corporate contracts will be analyzed and the impossibility of predisposition of all future contingencies and allocation of all existing risks in the contract, that is, the recognition that such contracts have lacunae and, consequently, are incomplete. In the second part of this dissertation, the concept of incomplete contracts will be analyzed, as well as its sources and manners for the solution of such contractual incompletion. Finally, on the last part of the second session, a modality of ascertainment of lacunae that seeks to preserve contractual ties in the event of conflict will be described, namely, renegotiation. / O presente trabalho tem por objetivo analisar os contratos empresariais de longa dura??o que possuem lacunas contratuais, sobremodo a partir da literatura de Direito e Economia. Em cen?rios de concorr?ncia perfeita, os instrumentos contratuais seriam capazes de prever todas as conting?ncias e estados da natureza. Todavia, mercados reais n?o refletem o modelo de concorr?ncia perfeito e, portanto, assim como pode haver lacuna no ordenamento jur?dico (artigo 4? da Lei de Introdu??o ?s normas do Direito Brasileiro), h? situa??es em que pode haver tamb?m lacuna no instrumento contratual redigido pelas partes a fim de atender a uma determinada finalidade. Trata-se do contrato incompleto, o qual em seu clausulado contratual apresenta alguma omiss?o, involunt?ria ou volunt?ria. Assim, na primeira parte do trabalho, ser? tra?ado um quadro geral dos contratos e suas rela??es com a economia e o mercado. Na sequ?ncia, ser? analisado o conceito de contrato empresarial de longa dura??o e a impossibilidade de predisposi??o de todas as conting?ncias futuras e da aloca??o de todos os riscos existentes no instrumento contratual, ou seja, o reconhecimento de que tais contratos possuem lacunas, isto ?, s?o incompletos. Na segunda parte do trabalho, ser? analisado o conceito de contrato incompleto, as suas fontes e as formas de solu??o da incompletude contratual. Por fim, na ?ltima parte da segunda se??o, ser? descrita uma modalidade de determina??o da lacuna que busca a preserva??o do v?nculo contratual no caso de conflito: a da renegocia??o.
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Efeito do tamanho do abrasivo no desgaste de metais. / The effect of abrasive size on the wear resistance of metallic materials.

John Jairo Coronado Marin 08 June 2010 (has links)
Neste trabalho, foi investigado o efeito do tamanho do abrasivo na resistência ao desgaste de cinco ligas metálicas. Foi usado, para este estudo, o equipamento pino contra lixa e alumina como abrasivo, com tamanho médio entre 16 µm e 192 µm. A microestrutura das ligas metálicas foi caracterizada com microscopia ótica e os mecanismos de desgaste abrasivo e os microcavacos (partículas de desgaste) foram caracterizados usando microscopia eletrônica de varredura (MEV). Em uma primeira série de experimentos, foi usado ferro fundido mesclado com carbonetos M3C (temperado e revenido a temperaturas entre 300 e 600°C). Para abrasivos pequenos, a perda de massa elevou-se com o aumento do tamanho do abrasivo. Entretanto, para abrasivos grandes, a perda de massa aumenta com inclinação menor e o mecanismo prevalente de desgaste é o microcorte. Para abrasivos maiores, o mecanismo prevalente de desgaste é microsulcamento. Em uma segunda série de experimentos, foi usado ferro fundido branco (FFB), com matrizes austenítica e martensítica. O FFB com matriz austenítica apresentou um tamanho crítico de abrasivo (TCA) de 36 µm e, para o ferro fundido martensítico, foi aproximadamente de 116 µm. A perda de massa do ferro fundido com matriz austenítica aumentou linearmente com o aumento do tamanho dos abrasivos, após o TCA a perda de massa aumenta com inclinação menor. O FFB martensítico, com menores tamanhos do abrasivo, apresentou um comportamento linear. Existe, porém, uma região de transição não-linear e achatada, quando o tamanho de partícula crítico é atingido, tornando-se independente do tamanho do abrasivo. Antes do TCA, o micromecanismo prevalente de desgaste foi microcorte e a lixa apresentou cavacos contínuos e finos e, após o TCA, o mecanismo prevalente de desgaste foi microsulcamento e apresentou cavacos descontínuos e deformados. O efeito do tamanho de abrasivo observado na perda de massa foi apresentado na energia especifica de corte e no coeficiente de atrito. Em uma terceira série de experimentos, foi usado alumínio e aço AISI 1045. O alumínio (estrutura cristalina cúbica de fase centrada) apresentou um comportamento similar ao observado no FFB com matriz austenítica, e o aço AISI 1045 apresentou um comportamento similar ao FFB com matriz martensítica. Verificou-se que, no alumínio e no aço AISI 1045, também se apresenta mudança na morfologia dos cavacos e nos micromecanismos de desgaste, observados nos materiais com segunda fase dura. Em uma quarta série de experimentos, foi usado o ferro fundido cinzento para corroborar a mudança dos micromecanismos de desgaste abrasivo e dos microcavacos com o TCA. O ferro fundido cinzento não apresentou uma transição (TCA) na curva de tamanho de abrasivo contra perda de massa. A morfologia dos cavacos foi similar para os diferentes tamanhos de abrasivos (descontínua). Para abrasivos menores, porém, apresentaram-se alguns cavacos contínuos e finos. O micromecanismo prevalente de desgaste abrasivo foi de microcorte para os diferentes abrasivos usados. Portanto, nesta pesquisa, foi demonstrado que o tamanho crítico de abrasivo está relacionado com os micromecanismos de desgaste e com a morfologia dos microcavacos. / In this research, the effect of abrasive size on the wear resistance of five metallic materials was investigated. Abrasive wear tests using a pin test on alumina paper were carried out using abrasive sizes between 16 µm and 192 µm. The wear surface of the specimens was examined by scanning electron microscopy for identifying the wear micromechanism and the type of microchips formed on the abrasive paper (wear debris). In a first series of experiments mottled cast iron samples with M 3 C carbides were tested. The samples were quenched and tempered in temperatures ranging from 300°C to 600°C. For small abrasive particles, the wear mass loss increased linearly with the increase of particle size. However, for higher abrasive sizes the wear mass loss increased much more slowly. For lower abrasive sizes the main wear mechanism was microcutting. For higher abrasive sizes, the main wear mechanism was microploughing. In a second series of experiments white cast iron with M 3 C carbide with austenitic and martensitic matrix were tested. The results show that the mass loss for cast irons with austenitic and martensitic matrices increases linearly with the increase of particle size until the critical particle size is reached. The cast iron with austenitic matrix presented a critical abrasive size of 36 µm and for the martensitic cast iron, the critical particle size was about 116 µm. After the critical particle size is reached, the rate of mass loss of the cast iron with austenitic matrix diminishes to a lower linear rate, and for cast irons with martensitic matrix the curve of mass loss is non-linear and flattens when the critical particle size is reached. It becomes, then, constant, independent of additional size increases. The abrasive paper in contact with the iron of both austenitic and martensitic matrices presents fine continuous microchips and the main wear mechanism was microcutting before reaching critical particle size, and after that it presents deformed discontinuous microchips and the main wear mechanism was microploughing. This behavior of change in rates after reaching a critical size happened not only for mass loss versus abrasive size, but it was also observed both in curves of friction coefficient and specific cutting energy versus abrasive size. In a third series of experiments aluminum and AISI 1045 steel were tested. The first (FCC structure) showed similar behavior to that observed in the white cast iron with austenitic matrix and the latter showed similar behavior to that observed in white cast iron with martensitic matrix. Both aluminum and AISI 1045 steel show similar changes in the microchips morphology and in the wear micromechanisms, something that had been observed before in materials with hard second phase. In a fourth series of experiments gray cast iron was tested in order to demonstrate the relationship between the abrasive wear micromechanisms and the type of microchips, before and after achieving critical abrasive size. The grey cast iron did not show a transition in the curve of abrasive size against mass loss. The morphology of the chips was similar for the different sizes of abrasive (discontinuous). However, smaller abrasive sizes some thin continuous microchips were formed. The main abrasive wear micromechanism was microcutting for the different abrasives sizes tested. Therefore, it was shown that the critical abrasive size is related to the wear micromechanisms and the microchips morphology.
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Influência da idade do fruto no período de incubação e na expressão de diferentes tipos de sintomas da mancha preta dos citros / Influence of fruit age on the incubation period and in the expression of different types of symptoms of citrus black spot

Frare, Guilherme Fernando 08 October 2015 (has links)
A mancha preta dos citros (MPC), causada por Phyllosticta citricarpa, é uma doença de importância econômica devido à redução na produtividade ocasionada pela queda prematura dos frutos e ao aumento dos custos da produção devido ao uso intensivo de fungicidas. As lesões restringem-se praticamente ao flavedo dos frutos, depreciando-os para a comercialização e restringindo a exportação de frutas in natura. A MPC causa danos em todas as espécies cítricas de valor comercial, com exceção da Citrus aurantium (laranja azeda) e do Citrus latifólia (lima ácida Tahiti). Phyllosticta citricarpa causa infecções latentes e diferentes tipos de sintomas nos frutos. Essas características podem estar relacionadas com o estádio fenológico do fruto no momento da infecção. Os objetivos desse trabalho foram avaliar a influência da idade dos frutos de laranja doce na germinação dos conídios e no período de incubação de P. citricarpa e identificar compostos fenólicos pré ou pós-formados no flavedo de frutos de laranja doce inoculados com P. citricarpa. Frutos de laranjeira das variedades Hamlin, Valência e Pêra com 1,5, 3,0, 5,0 e 7,0 cm de diâmetros foram inoculados com suspensão de conídios de P. citricarpa na concentração de 103 e 105 conídios.mL-1 e avaliados mensalmente. O primeiro sintoma observado foi o da falsa melanose e não foram observadas diferenças no período de incubação entre as variedades. O período de incubação da falsa melanose foi afetado pela concentração de inóculo e pelo diâmetro dos frutos. Frutos de 1,5 e 3,0 cm de diâmetro inoculados com suspensão de conídios de P. citricarpa, na concentração de 103 conídios.mL-1, apresentaram sintomas entre 70 e 116 dias respectivamente, enquanto que os frutos de 1,5, 3,0 e 5,0 cm de diâmetro, inoculados com suspensão de 105 conídios.mL-1, expressaram sintomas entre 40, 65 e 156 dias respectivamente. A expressão dos sintomas de mancha dura não diferiu entre as concentrações de inóculo, mas diferiu entre os diâmetros e entre as variedades avaliadas. A variedade Valência apresentou os menores tempos para o aparecimento dos sintomas quando comparado com as variedades Hamlin e Pêra. Os tempos médios para a expressão da mancha dura nos frutos (todas as variedades) inoculados com 1,5, 3,0, 5,0 e 7,0 cm de diâmetro foram 240, 217, 176 e 197 dias respectivamente. Sintomas de falsa melanose e mancha dura se expressaram independente um do outro. Não foi observado diferenças nas quantidades dos compostos fenólicos entre os frutos inoculados e não inoculados após 48 h de câmara úmida. As maiores quantidades de compostos fenólicos foram encontradas nos frutos menores e à medida que estes aumentaram de tamanho, observou-se a diminuição nas quantidades destes compostos. Não foram observadas diferenças no padrão de germinação do fungo em relação aos diferentes diâmetros inoculados, porém foram observadas placas de cera na superfície dos frutos de 7,0 cm de diâmetro. Os sintomas de falsa melanose parecem estar relacionados com a defesa da planta, e os sintomas de mancha dura estão relacionados com o estádio fenológico dos frutos. / Citrus black spot (CBS), caused by Phyllosticta citricarpa, is a disease of economic importance due to the reduction in yield, caused by premature fruit drop, and high production costs, due to the intensive fungicide spraying. The lesions are restricted to the fruit flavedo, decreasing market prices and restricting exports of fresh fruits. CBS causes damage in all commercial citrus species with exception of Citrus aurantium (sour orange) and Citrus latifolia (Tahiti acid lime). Phyllosticta citricarpa causes latent infections and different types of symptoms on fruit. These characteristics may be related to the phenological stage of the fruit at the time of infection. The objectives of this study were to evaluate the influence of fruit age of sweet orange on conidia germination and on the incubation period of P. citricarpa and identify phenolics pre or post-formed in the flavedo of sweet orange inoculated with P. citricarpa. Orange fruits of varieties Hamlin, Valencia and Pera with 1.5, 3.0, 5.0 and 7.0 cm of diameters were inoculated with a conidia suspension of P. citricarpa at the concentration of 103 and 105 conidia.mL-1 and were evaluated monthly. The first symptom observed was false melanose and no differences were found in the incubation period among the varieties. The incubation period of false melanose was affected by the inoculum concentration and fruit diameters. Fruits with 1.5 and 3.0 cm of diameter inoculated with a conidia suspension of P. citricarpa, at a concentration of 103 conidia.mL-1, showed symptoms between 70 and 116 days, respectively. On the other hand, fruits with 1.5, 3.0 and 5.0 cm in diameter, inoculated with suspension of 105 conidia.mL-1, expressed symptoms between 40, 65 and 156 days, respectively. The period for symptom expression of hard spot did not differ between inoculum concentrations. The incubation period differed between the diameters and varieties evaluated. The Valencia variety presented symptoms in a shorter time than Hamlin and Pera. The average times for hard spot expression in fruits (all varieties together) inoculated with 1.5, 3.0, 5.0 and 7.0 cm of diameter were 240, 217, 176 and 197 days, respectively. Symptoms of false melanose and hard spot were expressed independently from each other. No differences were observed in the amounts of phenolic compounds between inoculated and non-inoculated fruits after 48 h of incubation in a humid chamber. The highest amounts of phenolic compounds were found in smaller fruits and, as fruits increased size, there was a decrease in the amounts of these compounds. No differences were found in the germination pattern of fungus on the inoculated fruits, but wax plates were observed on the surface of fruits with 7.0 cm in diameter. Symptoms of false melanose seem to be related to the plant defense mechanism, and symptoms of hard spot appeared to be related with phenological stages of the fruits.

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