Le remplacement des Stellites, un superalliage base cobalt, en milieu nucléaire dans certaines parties du réacteur en milieu primaire a été étudié depuis les années soixante. Plusieurs nuances de revêtements base Fer et Nickel, sans ou avec très peu de cobalt, ont été développées dans ce sens. La quatrième génération de centrale impose également des conditions de fonctionnement très sévère pour les revêtements durs. L’idée principale de ce travail de thèse est de renforcer des nuances commerciales de superalliages base nickel avec des particules micrométriques et sub-micrométriques d’alumine par plasma d’arc transféré, Cold Spray et coprojection plasma simultanée de poudre et de suspension.Pour les dépôts PTA, l’analyse des dépôts a montré un raffinement de la microstructure mais une répartition inhomogène de l’alumine. L’ajout d’alumine n’a pas influé sur la microdureté des dépôts mais a permis d’améliorer la résistance à l’usure abrasive sous air. Les dépôts obtenus par projection plasma, en combinant projection classique de poudre et de suspension d’alumine, ont montrés un meilleur comportement tribologique sous conditions particulières. Les effets de l’ajout d’alumine dans la matrice ont été étudiés en observant la microstructure et en comparant les propriétés mécaniques des dépôts (micro dureté, et tests tribologiques représentatifs de l’application) pour différents taux de renforts (de 0 à 13% pds). / In nuclear plants, the replacement of hardfacing Stellite, a cobalt-base alloy, on parts of the piping system in connection with the reactor has been investigated since the late 60’s. Various Fe-base or Ni-base alloys, Co-free or with a low content of Co, have been developed in this aim. The 4th generation nuclear plants impose additional or more stringent requirements for hardfacing materials. The idea developed in this work is to reinforce commercial nickel base alloy with addition of micrometric and sub-micrometric alumina particles by Plasma Transferred Arc welding, Cold Spray and simultaneous conventional and suspension plasma spray.For PTA Coatings, the examination of coatings revealed a refinement of the microstructure but an inhomogeneous alumina distribution. The addition of alumina particles did not improve the micro-hardness of coatings but improve their resistance to ambient air abrasive wear.The coatings prepared by plasma spraying, combining powder of metallic matrix and suspension of ceramic particles, showed better tribological performance under particular conditions. The effect of the addition of ceramic particles in the matrix was investigated by observing the microstructure of coatings, and comparing their mechanical behavior (micro hardness and tribological tests representative of the application) for different ceramic particle contents (from 0 to 13 wt%).

No description available.

The aim of the study is to evaluate the efficacy of percutaneous transluminal angioplasty in reduction of the lower limb ischemia and to investigate the influence of this procedure on the lower limb salvage rate. The introduction defines the objectives and tasks of the study, includes a literature review, a summary of the main problems related to the theme. A separate chapter describes the research methodology. The study analysed the treatment results of 146 patients who underwent the iliac artery percutaneous transluminal angioplasty. The following PTA efficacy criteria were determined - the increase of ankle-brachial index and the decrease of ischemia according to Fontaine stages of limb ischemia. It was also found that the substantial PTA effect of the iliac artery and the need for additional interventions become evident during the early postoperative period (1–7 days after PTA), and the effect of angioplasty decreases gradually during one year follow-up after the procedure. To arrest the progression of ischemia an additional endovascular procedure or an open surgery of femoral, popliteal and the crural arteries is necessary. The majority of these operations or procedures are reconstructive operations of the femoral, popliteal and the crural arteries. The effectiveness of the iliac artery PTA depends on the stage of lower limb ischemia. The need of an additional intervention is determined by the nature of lesion of the femoral arteries and the increase in ankle-brachial... [to full text] / Tyrimo tikslas – nustatyti klubo arterijų perkutaninės transliuminalinės angioplastikos veiksmingumą mažinant apatinių galūnių išemiją ir ištirti, kokios įtakos ši gydomoji procedūra turi galūnių amputacijos dažniui. Įvade išdėstomi tyrimo tikslai bei uždaviniai, pateikiama literatūros apžvalga, kurioje apibendrinamos pagrindinės su nagrinėjama tema susijusios problemos. Atskirame skyriuje aprašyta tyrimo metodika. Disertacijoje išnagrinėti 146 pacientų, kuriems atlikta klubo arterijų perkutaninė transliuminalinė angioplastika, gydymo rezultatai. Nustatyta, kad kriterijai angioplastikos veiksmingumui įvertinti – kulkšnies-žasto indekso pokytis, išemijos sumažėjimas pagal Fontaine’o galūnės išemijos stadijas. Taip pat nustatyta, kad klubo arterijos PTA pakankamas efektas ir papildomų intervencijų poreikis daugiausia išryškėja ankstyvuoju pooperaciniu laikotarpiu (iki 7 dienų po PTA), o PTA rezultatai laipsniškai blogėja per vienerius metus. Išemijos progresavimui sustabdyti reikalinga šlaunies, pakinklio ir blauzdos arterijų papildoma endovaskulinė arba atviroji operacija, dažniausiai – rekonstrukcinės arterijų operacija. Klubo arterijų angioplastikos veiksmingumas priklauso nuo išemijos stadijos. Papildomos intervencijos poreikį po PTA lemia šlaunies arterijų pažeidimo pobūdis, kulkšnies-žasto indekso pokytis mažiau negu 0,15. Bendras pacientų sergamumas kitomis ligomis pakankamos angioplastikos ir papildomų intervencijų grupėje buvo vienodas. Iš tirtų periferinių arterijų... [toliau žr. visą tekstą]

The microstructures and performance of Ni-based alloys and Ni-WC (nickel-tungsten carbide) composite overlays deposited by plasma transferred arc welding have been studied. The Ni-alloy overlays had similar microstructures consisting of Ni dendrites, with interdendritic Ni-based eutectics, borides and carbides. Low hardness alloy overlays contained a smaller fraction of interdendritic phases relative to the high hardness alloys. The interdendritic regions make a significant contribution to the hardness since they are more than twice as hard as primary dendrites. The Ni-WC composites contained similar phases, however WC dissolution was observed leading to the formation of other carbides. Ni-alloys with low carbon and Cr content exhibited the lowest WC dissolution. The Ni-WC overlays produced using these dilute alloys generally performed better in ASTM G65 wear tests. This was likely due to the reduced dissolution which avoided formation of brittle secondary phases, maintaining a short mean free path between WC particles and allowing increased impact energy absorption. / Materials Engineering

No description available.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Grande parte do petrÃleo nacional encontra-se em ambiente offshore, onde suas condiÃÃes de extraÃÃo apresentam nÃveis crÃticos de tensÃo e um alto potencial corrosivo. Um dos grandes desafios do setor à assegurar as propriedades de juntas submarinas de aÃos soldadas quanto à resistÃncia mecÃnica, tenacidade e dureza, onde as mesmas, expostas a proteÃÃo catÃdica, podem sofrer fragilizaÃÃo por hidrogÃnio. Com o objetivo de evitar a necessidade de tratamento tÃrmico pÃs-soldagem no amanteigamento das juntas, uma alternativa à o emprego da tÃcnica dupla camada, a qual por meio da relaÃÃo adequada de energia de soldagem da primeira e segunda camada, visa-se obter o revenimento e o refino da estrutura com a sobreposiÃÃo de ciclos tÃrmicos. Para selecionar os parÃmetros utilizados nas camadas foram realizados os Testes Higuchi, depositando a liga de nÃquel UNS N06625 no aÃo baixa liga alta resistÃncia AISI 8630M com o processo de soldagem plasma com arco transferido, empregando material de adiÃÃo na forma de pà (PTA). As soldagens foram realizadas variando-se a energia de soldagem, a tÃcnica de soldagem e o gÃs de proteÃÃo. A partir das extensÃes de zona dura (ZD), zona macia (ZM), regiÃo grÃo grosso (ZACGG) e regiÃo grÃo fino (ZACGF) da zona afetada pelo calor obtidas com realizaÃÃo de perfis de microdureza e microscopia Ãtica, foi encontrada uma melhor relaÃÃo de energia, que promovesse o revenimento e o refino da microestrutura da ZAC. Juntas dos aÃos AISI 8630M e ASTM A182 F22 foram amanteigadas com as relaÃÃes de energia obtidas utilizando o processo PTA e enchidas utilizando o processo MIG. Nas interfaces dissimilares geradas entre os aÃos baixa liga alta resistÃncia e a liga de nÃquel UNS N06625 do amanteigamento foi realizada caracterizaÃÃo microestrutural e suas propriedades mecÃnicas foram medidas com a realizaÃÃo de microdureza, dureza e ensaio de fratura, visando avaliar a eficiÃncia dos Testes Higuchi. TambÃm foram analisadas a interface gerada entre a liga de nÃquel na forma de pà (amanteigamento) e na forma de arame (enchimento da junta) com microscopia Ãtica e dureza. As juntas amanteigadas na condiÃÃo indicada pelos testes Higuchi apresentaram um intenso refino na ZAC do aÃo baixa liga. A interface dissimilar apresentou uma composiÃÃo quÃmica intermediÃria entre os aÃos utilizados e a liga de nÃquel. A zona afetada pelo calor (ZAC) das amostras amanteigadas apresentaram uma diminuiÃÃo nos valores de dureza, no entanto para ambos os aÃos esses valores foram superiores aos estabelecidos pelas normas que regem a sua aplicaÃÃo. Os ensaios de fratura indicam que o fator de intensidade de tensÃo (K) encontrado para as amostras amanteigadas foram condizentes com a literatura. / Much of the domestic oil is located offshore environment where their extraction conditions have critical levels of strain and a high corrosion potential. One of the major challenges the sector is to ensure the properties of underwater joints welded steel as the mechanical strength, toughness and hardness, where the same exposed to cathodic protection can suffer hydrogen embrittlement. With the aim of avoiding the need for post-welding heat treatment of the buttering joints, an alternative is the use of double layer technique, which by means of suitable welding power ratio of the first and second layer, the aim is to obtain the tempering and refining structure with overlapping thermal cycles. To select the parameters used in the tests Higuchi layers were carried out by depositing nickel alloy UNS N06625 in high strength low alloy steel AISI 8630M with the process of welding plasma transferred arc, employing filler metal in powder form (PTA). The weldments were performed varying the welding energy, the welding technique and the shielding gas. From extensions harsh zone (HZ), soft zone (SZ), rough grain region (HAZRG) and fine grain region (HAZFG) of the heat affected zone obtained by performing microhardness and optical microscopy, better energy ratio was found, which promotes tempering and refining the microstructure of HAZ. Joints of AISI 8630M and ASTM A182 F22 were buttery with energy ratios obtained using the PTA process and filled using the MIG process. In the dissimilar interfaces generated between the low alloy high strength steels and nickel alloy UNS N06625 buttering the microstructural characterization was performed, and their mechanical properties were measured by carrying out hardness, hardness and fracture test, to evaluate the efficiency of tests Higuchi. The generated interface between the nickel alloy in powder form (buttering) and in the form of wire (joint filler) were anayzed using optical microscopy and hardness tests. The buttery joints in the condition indicated by Higuchi tests showed an intense refining HAZ of the low alloy steel. The dissimilar interface had a chemical composition intermediate between the steel used and nickel alloy. The heat affected zone (HAZ) of buttery showed a decrease in hardness, however for both steels these values of hardness test were higher than those established by the rules governing its application. The fracture test indicate that the fracture stress intensity factor (K) found for the buttery samples were consistent with the literature.

Thesis advisor: Robert Murphy / Given the increasing proliferation of preferential trade agreements, this work seeks to investigate the economic, political, and cultural relationships that may be built from the common foundation of a trade agreement. It evaluates the experiences of the European Union and the North American Free Trade Agreement and makes predictions and suggestions for future preferential trading partners, as well as analyzing the potential impact that PTAs will have on globalization and international relations. / Thesis (BA) — Boston College, 2004. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: International Studies. / Discipline: College Honors Program.

Submitted by Amanda Silva (amanda.osilva2@ufpe.br) on 2015-03-04T13:02:20Z No. of bitstreams: 2 _Dissertação_Erick_definitiva.pdf: 1573697 bytes, checksum: 6943380e245fdaf2368ad3a1ce00d608 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-04T13:02:20Z (GMT). No. of bitstreams: 2 _Dissertação_Erick_definitiva.pdf: 1573697 bytes, checksum: 6943380e245fdaf2368ad3a1ce00d608 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2013 / ANP; FINEP / Um dos grandes desafios da indústria é buscar o desenvolvimento sustentável no processo produtivo industrial. A baixa disponibilidade de água como matéria-prima em processos produtivos e a crescente exigência da sociedade por um meio ambiente mais saudável têm impulsionado a implantação de programas de minimização do consumo de água e reutilização de efluentes líquidos. Esta prática pode contribuir de forma significativa com a preservação dos recursos hídricos naturais, inclusive com a redução da captação de águas primárias. A Petroquímica Suape, em Pernambuco, iniciou em 2013 a produção de ácido tereftálico (PTA) que é a principal matéria-prima usada na produção do politereftalato de etileno (PET), gerando grande quantidade de efluentes que são tratados por processo biológico anaeróbio seguido de aeróbio. O tratamento de efluentes industriais contendo PTA apresenta dificuldades operacionais devido à toxicidade deste composto. Os processos oxidativos avançados (POA) apresentam facilidade em degradar contaminantes orgânicos tóxicos e resistentes ao tratamento biológico porque se baseiam na geração de radicais hidroxilas que são altamente reativos e pouco seletivos. Este estudo teve como objetivo avaliar a eficácia e a cinética da degradação do ácido tereftálico com processo de fotocatálise heterogênea com radiação solar artificial em presença oxigênio e catalisador TiO2. Foi usado um reator agitado em batelada para tratar um efluente modelo contendo 20 mg L-1 de PTA, com oxigênio adicionado através de borbulhamento de ar comprimido. A análise do efluente tratado foi feita via carbono orgânico total (COT) e determinação da concentração de PTA via espectroscopia UV-visível. As melhores condições operacionais foram obtidas através de um planejamento composto central rotacional, variando-se o pH e a concentração de catalisador TiO2. Um estudo cinético foi realizado variando-se as concentrações de PTA de 20 a 90 mg L-1. Os resultados mostram que a melhor condição de operação foi obtida em pH 5,5 e concentração de TiO2 igual a 1,0 g L-1, a qual foi observada máxima conversão de COT de 93% e conversão de PTA de 98,8%, após 90 minutos de reação. A degradação fotocatalítica de PTA sobre TiO2 seguiu um modelo cinético de pseudo-primeira ordem. Os parâmetros cinéticos de Langmuir-Hinshelwood foram ajustados com um coeficiente de regressão bem satisfatório. A toxicidade do efluente modelo após tratamento foi determinada por metodologia de germinação de sementes de alface. O efluente tratado foi classificado como sendo de baixa toxicidade de acordo com critérios do IBAMA. Dessa forma o processo de fotocatálise heterogênea com TiO2 mostrou-se tecnicamente viável para o tratamento do ácido tereftálico, podendo ser usado como pré-tratamento do efluente industrial antes do tratamento biológico convencional e abrir alternativas para futuros estudos de reuso de água na indústria.

Bakgrund: Percutan transluminal angioplastik (PTA) är ett ingrepp som syftar till att behandla patienter med besvär orsakade av ateroskleros med förträngningar i artärer. PTA går ut på att vidga kärlets diameter och ibland sätts en stent in i kärlet för att behålla öppenheten. Som röntgensjuksköterska ingår möten med patienter som genomgår PTA före, under och efter ingreppet. Syfte: Litteraturstudiens syfte är att belysa de vanligaste sena komplikationerna som kan uppstå vid PTA. Metod: Det här arbetet är en systematisk litteraturstudie. Inklusionskriterierna var vetenskapliga artiklar skriva mellan 2007 till 2018. Artiklarna var peer-reviewed och etiskt granskade. Databaserna CINAHL och MEDLINE användes vid sökningen. Relevans bedömdes med Critical Appraisal Skills Programme. Resultat: 20 vetenskapliga artiklar inkluderades i studien, samtliga visar på restenos. Stentfraktur förekom i 5 av 20 studier och amputation i 14 av 20 studier. Slutsats: Slutsatsen är att restenos är den vanligaste sena komplikationen oavsett om stent har använts eller inte i samband med PTA av nedre extremiteter. Om stent används finns risken för stentfraktur. Dock är denna risk inte lika stor som risken för restenos. Fortsatt forskning kring läkemedelstäckta ballonger och stentar behövs då det i dagsläget tyder på att färre antal patienter drabbas av restenos vid användandet av dessa. / Background: The purpose of percutanous transluminal angioplasty (PTA) is to treat patients with symptoms and discomfort because of stenosis and occlusions in the arteries caused by atherosclerosis. This is done by dilatation of the vessel diameter and sometimes placing a stent to maintain the patency of the artery. Working as a radiographer includes meeting patients before, during and after PTA. Purpose: The purpose of this study is to illustrate the most common late complications that can occur after PTA. Method: This is a systematic literature study. The inclusion criteria for the articles were to follow a scientific structure, they had to be published between 2007 and 2018 and they had to be peer-reviewed and ethically reviewed. The databases used in this study were CINAHL and MEDLINE. Critical Appraisal Skills Programme was used. Result: 20 scientific articles were included in this study. All of them reported restenosis. Stent fractures occurred in 5 of 20 studies and amputation occurred in 14 of 20 studies. Conclusion: Restenosis was the most common late complication of PTA both with and without stent placement. More research is needed using drug-coated balloons and drug-coated stents to see if there are any beneficial effects.

本研究旨在瞭解臺北市國民中學家長會之運作現況，分析家長會參與學校事務、學校支援方面的認知與成效，再依據研究結果，提出建議，做為家長會運作之參考。 本研究方法為問卷調查法。研究對象為臺北市家長會成員。問卷回收後分別以描述統計，獨立樣本t考驗、單因子變異數分析等統計方法分析。根據研究結果將結論分析歸納如下： 一、臺北市國民中學家長會在會務推動方面受家長肯定，惟家長普遍對家長會功能認知有偏低現象。 二、臺北市國民中學家長會運作在校務參與方面最重視班級經營。 三、臺北市國民中學家長會願意協助學校發展，其中人力或財力為協助學校最直接且有利的方式。 四、臺北市國民中學家長會運作正常，具備組織與成效，且對學校教育效能有所助益。 五、臺北市國民中學家長在家長會的參與及運作時不受其背景變項影響。 最後，依據研究結論，提出幾點建議提供家長會、學校、主管教育行政機關及後續相關研究做參考。 / This study aims to understand where PTA (parent teacher associations of Taipei city’s junior high schools) stands, assessment of current operation and function and involvement regarding to the parents. Based upon the full analysis, we made suggestions for PTA. Questionnaires are given to respondents who were parents, splintered by groups for the sake of statistics of those samples. We have achieved the following conclusions: 1.Parents felt positive to PTA for pushing forward agenda, but had low comprehension as to PTA’s functions. 2.PTA in daily operation placed most importance was class operation. 3.Parents were willingly to support school, by means of most straight forward: either manpower or financial support. 4.PTA remained well operational, organized and efficient, which enhanced scholastic functions. 5.PTA were not affected by background of parents (income and social status, etc.) According to the research result, we had achieved the conclusions and would like to propose to PTA, schools, and the scholastic administrative unit for better understanding and further improvement.