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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.
201

Biaxial böjhållfasthet på högtranslucent zirkonia efter värme-, ytbehandling, recementering och långtidsförvaring / Biaxial flexural strength on high translucent zirconia after heat-, surface treatment, re-cementation and longterm storage

Cristurean, Anamaria Lucretia, Kirakosian, Alin January 2022 (has links)
Syfte  Syftet med föreliggande studie var att undersöka hur böjhållfastheten på zirkonia påverkas av värmebehandling, ytbehandlingar vid re-cementering och långtidsförvaring i cirka två år. Material och metod I en tidigare studie av A.Cervenka och H. Ekdahl (7) designades 30 stycken zirkoniahättor, med måtten 6 mm i tjocklek och 14 mm i ⌀(Z-CAD, HTL, Metoxit), i ett CAD-program (3shape) och frästes (DATORN 5).  Zirkoniahättorna delades in i tre grupper med tio provkroppar i varje grupp, beroende på ytbehandling: kontrollgrupp (C), sandblästring med aluminiumoxid (A) och skrapning (S). Zirkoniahättorna cementerades på titandistanser. Grupp S och grupp A utsattes för värmebehandling, för att kunna lossa hättorna från titandistanserna. Överskottet av cement avlägsnades genom två olika ytbehandlingar innan recementering (A respektive S). Samtliga grupper termocyklades i 5000 cykler (5° till 55°) innan de utsattes för ett draghållfasthetstest. När föreliggande studie genomfördes hade zirkoniahättorna förvarats torrt i rumstemperatur i cirka två år. Zirkoniahättornas underdel slipades ner till 2,9 mm i tjocklek i en slipmaskin (Phoneix 4000) för att tillverka provkroppar lämpade för utförande av ett biaxialt böjhållfasthetstest. Resultaten analyserades med One-way ANOVA, Tukey’s test med en signifikansnivå på α =0,05.   Resultat Det biaxiala böjhållfasthetstestet påvisade att grupp C hade högst medelvärde och S hade lägst medelvärde. Det fanns inte någon signifikant skillnad mellan grupperna, p>0,05.  Slutsats Inom ramen för föreliggande studie kan följande slutsats dras:  Böjhållfastheten på zirkoniahättor som har långtidsförvarats i cirka två år påverkas inte av tidigare genomförd värmebehandling och olika ytbehandlingar vid recementering / Purpose The purpose of the present study was to investigate how the flexural strength of zirconia is affected by heat treatment, various surface treatments during re-cementation, and long term storage for about two years. Material and method In a previous study by A.Cervenka and H. Ekdahl (7), 30 zirconia copings, measuring 6 mm in thickness and 14 mm in ⌀ (Z-CAD, HTL, Metoxit), were designed in a CAD-program (3shape) and milled (DATORN 5). Zirconia copings were divided into three groups with ten specimens in each group, depending on different surface treatment: control group (C), aluminum oxide abrasion group (A) and scraping (S). Zirconia copings were cemented on titanium abutments. Group S and group A were subjected to heat treatment in order to be able to detach the zirconia copings from titanium abutments. The excess cement was removed by two various surface treatments before the recementation (A respective S). All groups were thermocycled for 5000 cycles (5 ° to 55 °) before being subjected to a tensile strength test. At the time of the present study zirconia copings had been stored dry at room temperature for about two years. The lower part of the zirconia copings was reduced to 2.9 mm in thickness using a grinding machine (Phoneix 4000)in order to produce specimens suitable to performe a biaxial flexural strength test. The results were analyzed with One-way ANOVA, Tukey's test with a significance level of α = 0.05.. Results The biaxial flexural strength test showed that group C had the highest mean and S had the lowest mean. There was no significant difference between the groups, p> 0.05.  Conclusion Within the limitations of this study, the following conclusion can be drawn: The flexural strength of zirconia copings that have been stored for about two years is not affected by previously heat treatment performed during recementation and various surface treatments during recementation.
202

Efficiency and Roughness Characteristics of Surface Treated Powder Metal Electric Vehicle Gears

Mohandas, Vyshak, Thazhathe Kalathil, Sreekuttan January 2023 (has links)
This thesis presents an experimental research study aimed at identifying the optimal mechano-chemical surface treatment for powder metallurgy gears utilized in electric vehicles (EVs). The primary objective of the study is to determine the most effective surface treatment method in terms of enhancing gear transmission efficiency. The experiments utilise a specialized FZG test rig, which allows for comprehensive testing under realistic operating conditions. In addition, a surface roughness measurement device is used to evaluate the impact of the surface treatments on the gear's surface characteristics. The results obtained from the experiments reveal a particular type of surface treatment as the most effective among the test samples considered within the scope of the thesis, as it significantly improves gear transmission efficiency. These findings contribute to the advancement of surface treatment techniques for powder metallurgy gears used in EVs, aiding in the development of more efficient and high-performing gear systems for electric mobility. / Denna avhandling presenterar en experimentell forskningsstudie som syftar till att identifiera den optimala mekano-kemiska ytbehandlingen för pulvermetallurgiväxlar som används i elfordon (EV). Det primära syftet med studien är att fastställa den mest effektiva ytbehandlingsmetoden när det gäller att förbättra effektiviteten i växelöverföringen. Experimenten utförs med hjälp av en specialiserad FZG-testrigg, som möjliggör omfattande tester under realistiska driftsförhållanden. Dessutom används en ytråhetsmätningsanordning för att utvärdera effekten av ytbehandlingarna på kugghjulets ytegenskaper. Resultaten från experimenten avslöjar en viss typ av ytbehandling som den mest effektiva bland de testprover som betraktas inom ramen för avhandlingen, eftersom den avsevärt förbättrar växeltransmissionens effektivitet. Dessa fynd bidrar till utvecklingen av ytbehandlingstekniker för pulvermetallurgiska redskap som används i elbilar, vilket hjälper till att utveckla mer effektiva och högpresterande växelsystem för elektrisk mobilitet.
203

Investigation of micropitting and wear in rolling/sliding contacts operating under boundary lubrication conditions

Hasan, Mushfiq January 2021 (has links)
No description available.
204

Robust human-robot collaboration for polishing tasks in the automotive industry

García Fernández, Alberto 20 October 2023 (has links)
[ES] La presente tesis aborda la Interacción Humano-Robot para tareas industriales de tratamiento superficial, con el objetivo de obtener una verdadera sinergia entre el operador humano y el sistema robotizado, así como un funcionamiento robusto. En concreto, la tesis establece las bases sobre las cuales un robot con asistencia por teleoperación o autónomamente interacciona con los humanos y con los otros robots en la zona de trabajo. Las propuestas se validan mediante experimentación real utilizando hasta dos robots manipuladores 6R y 7R respectivamente. Las principales contribuciones son: - Asistencia robótica para el lijado industrial con aproximación suave a la superficie y restricciones de límite - Control de robots bimanuales usando teleoperación asistida para tareas de tratamiento superficial - Interfaz basada en Realidad Aumentada para la teleoperación de robots bimanuales La aplicación de técnicas de Control en Modo Deslizante (SMC, por sussiglas en inglés) tanto convencional como no convencional y una arquitectura de control basada en prioridades son las herramientas clave para el desarrollo de estas contribuciones. / [CA] La present tesi aborda la Interacció Humà-Robot per a tasques industrials de tractament de superfícies, amb l'objectiu d'obtindre una veritable sinergia entre l'operador humà i el sistema robotitzat, així com un funcionament robust. En concret, la tesi estableix les bases sobre les quals un robot amb assistència per teleoperació o autònomament interacciona amb els humans i amb els altres robots a la zona de treball. Les propostes es validen mitjançant experimentació real utilitzant fins a dos robots manipuladors 6R i 7R, respectivament. Les principals contribucions són: - Assistència robòtica per al poliment industrial amb aproximació suau a la superfície i restriccions de límit - Control de robots bimanuals emprant teleoperació assistida per a tasques de tractament superficial - Intefaç basada en Realitat Augmentada per a la teleoperació de robots bimanuals L'aplicació de tècniques de Control en Mode Lliscant (SMC, per les seues sigles en anglés)tant convencional com no convencional i una arquitectura de control basada en prioritats són les eines clau pel desenvolupament d'aquestes contribucions. / [EN] The present thesis work addresses Human-Robot Interaction for industrial surface treatment tasks, aiming to attain a true synergy between the human operator and the robot system, as well as a robust performance. Specifically, this thesis establishes the basis on which a robot, either assisted by teleoperation or working autonomously, interacts with humans and with other robots in its working area. These proposals are validated through real experimentation using up to two robot manipulators, 6R and 7R respectively. The main contributions are: - Robotic assistance for industrial sanding with a smooth approach to the surface and boundary constraints - Bimanual robot control using assisted teleoperation for surface treatment tasks - Augmented reality-based interface for bimanual robot teleoperation The appliance of conventional and non-conventional Sliding Mode Control (SMC) techniques and a priority-based control architecture are the fundamental tools for the development of these contributions. / García Fernández, A. (2023). Robust human-robot collaboration for polishing tasks in the automotive industry [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/198673
205

Rôle des interfaces dans les propriétés macroscopiques de composites C/C

Podgorski, Michael 23 October 2009 (has links)
Les composites Carbone/Carbone (C/C), largement utilisés à hautes températures dans des environnements oxydants, sont sensibles à l'oxydation dès 400°C. Deux voies sont envisagées pour accroître la tenue à l'oxydation de ces matériaux. La première est de renforcer la force de la liaison fibre/matrice en modifiant les propriétés de surface des fibres de carbone. La seconde voie d 'étude consiste à remplacer une partie de la matrice carbone par un oxyde. L'introduction d'une nouvelle phase conduit à la création de nouvelles interfaces dans les matériaux. L'ensemble des résultats obtenus à partir des caractérisations physico-chimiques et macroscopiques des matériaux élaborés permettent alors de répondre à la problématique qui est de connaître le rôle des interfaces dans les propriétés macroscopiques de composites C/C. / C/C composites are widely used as structural parts in oxiding environment. Yet, they become very sensitive to air oxidation for temperature higher than 400°C. This work proposed two methods to improve their oxidation resistance :(i) the fiber/matrix bond is increased by modifying the properties of the carbon fiber surface, and (ii) a fraction of the carbon matrix is substitued by an oxide phase.Introduction of new constituants leads to the creation of new material interfaces. Thus, the influence of the interfaces on the macroscopic properties of the composite is evaluated by physico-chemical and macroscopic characterizations.
206

Resistência de união de tratamentos de superfície realizados anteriormente à realização de restaurações em resina composta / Bonding strength of surface treatments performed prior to composite resin restorations

Colombini, Caio Piccolo 30 January 2019 (has links)
As lesões cervicais não cariosas (LCNCs) são definidas pela perda de estrutura dental na junção cemento/esmalte que envolve três mecanismos de estresse mecânico (tensão), atrito (fricção) e erosão (degradação química).. Existem tratamentos preventivos e dessensibilizantes para o principal sintoma das LCNCs, a hipersensibilidade dentinária cervical (HDC), porém, em casos que há perda de estrutura dental maior que 1mm é necessário realizar uma intervenção restauradora. Dessa forma, o objetivo deste estudo foi avaliar a resistência de união da dentina erodida e abrasionada modificada com diferentes pré-tratamentos e posteriormente restauradas com resina composta, através do teste de microtração. Para tanto, foram selecionados 40 molares humanos íntegros, que tiveram as porções oclusais seccionadas até exposição da dentina. Os espécimes passaram por desafio erosivo e abrasivo em uma ciclagem de 5 dias. Após os desafios, os espécimes receberam os tratamentos de superfície (n=10): G1: controle sem tratamento; G2: tratamento de superfície com ponta diamantada; G3: jateamento com óxido de alumínio, G4: ciclagem com enxaguatório fluoretado Elmex Erosion. Feito isso os espécimes foram restaurados, seccionados em palitos e submetidos ao teste de microtração em uma máquina universal de ensaios a 0,5mm/min. Para a analise estatística, foi utilizado o teste paramétrico de análise de variância (ANOVA) um fator e o teste auxiliar de Tukey. Foi observado que não houve diferença entre os tratamentos com ponta diamantada, óxido de alumínio e enxaguatório fluoretado. O único grupo a se diferenciar dos demais foi o grupo controle que apresentou valores de resistência de união inferiores. Dentro das limitações de um trabalho in vitro, conclui-se que os tratamentos de superfície estudados são procedimentos indicados para melhorar a adesão dental frente à necessidade de restaurar uma LCNC. / Non-carious cervical lesions (NCCLs) are defined by loss of dental structure at the cement/enamel junction involving three mechanisms of mechanical stress (tension), friction and erosion (chemical degradation). There are preventive and desensitizing treatments for the the main symptom of NCCLs, cervical dentin hypersensitivity (CDH), but in cases where there is loss of tooth structure greater than 1mm, a restorative intervention is necessary. Thus, the objective of this study was to evaluate the bond strength of the eroded and abraded dentin modified with different pre-treatments and later restored with composite resin, through the microtensile test. For this, 40 sound human molars were selected, which had the occlusal portions sectioned until exposure of the dentin. The specimens underwent erosive and abrasive challenge in a 5-day cycling. After the challenges, the specimens received the surface treatments (n = 10): G1: control without treatment; G2: surface treatment with diamond tip; G3: sandblasting with aluminum oxide, G4: cycling with fluoridated rinse Elmex Erosion. After this, the specimens were restored, sectioned on sticks and subjected to the microtensile test in a universal test machine at 0.5mm/min. For statistical analysis, the parametric analysis of variance (ANOVA) one factor and the Tukey auxiliary test were used. It was observed that there was no difference between treatments with diamond tip, aluminum oxide and fluoride. The only group to differentiate from the others was the control group that presented inferior bond strength values. Within the limitations of an in vitro work, it is concluded that the surface treatments studied are procedures indicated to improve dental adhesion in view of the need to restore NCCL.
207

Influência do meio de conservação e efeito do tratamento de superfície na anquilose e na reabsorção de tecidos mineralizados após o reimplante de dentes avulsionados / Influence of the storage medium and effect of root surface treatment on ankylosis and resorption of mineralized tissues after tooth replantation

Longo, Daniele Lucca 03 July 2017 (has links)
O tratamento preconizado para dentes permanentes avulsionados devido a traumatismos dentários em crianças é o reimplante dental. Entretanto, sabe-se que o sucesso após o reimplante depende, especialmente, do tempo em que o dente permanece fora do alvéolo e do meio de conservação no qual o dente é armazenado. Nesse sentido, para que se tenha sucesso após o reimplante faz-se necessário que o dente seja imediatamente reimplantado e/ou seja mantido em um meio capaz de manter a vitalidade das células da superfície radicular. Se isso não for possível, o tratamento da superfície radicular deverá ser instituído com o objetivo de prevenir a reabsorção radicular. Dessa maneira, esta pesquisa teve como primeiro objetivo avaliar a influência de diferentes meios de conservação para dentes avulsionados, por meio de uma revisão sistemática, com a finalidade de estabelecer se há um consenso sobre o meio mais adequado para conservação capaz de prevenir sequelas como anquilose e reabsorção dentária. A seguir, o segundo objetivo desse estudo foi testar o Denosumab, um anticorpo monoclonal anti-RANKL, como substância para o tratamento tópico da superfície radicular, a fim de evitar a anquilose e a reabsorção dentária por substituição. Para tanto, foram utilizados 36 incisivos superiores direitos de ratos submetidos à extração cirúrgica, manutenção em meio extra-alveolar seco por 60 minutos e posterior reimplante. No grupo I, controle positivo, foi realizado o reimplante tardio sem tratamento de superfície; nos grupos II e III, grupos experimentais, previamente ao reimplante tardio foi realizado o tratamento da superfície radicular com solução de Denosumab a 60 mg/mL e a 30 mg/mL, respectivamente, por 10 minutos. Os canais radiculares dos animais dos três grupos foram preenchidos com pasta à base de hidróxido de cálcio, via retrógrada, e em seguida os dentes foram reimplantados. Decorridos 15 e 60 dias do reimplante, os animais foram submetidos à eutanásia e as peças, contendo dente e osso, foram removidas para o processamento histotécnico. A seguir cortes histológicos foram realizados, corados por hematoxilina e eosina (HE), para descrição das características da superfície dentária e do ligamento periodontal e para mensuração do comprimento (perímetro) da anquilose e/ou reabsorção por substituição e das áreas de reabsorção dentária, em microscopia de luz e, para mensuração da área do ligamento periodontal, em microscopia de fluorescência. Espécimes sequenciais foram analisados por meio de coloração de Brown & Brenn modificada para identificação de micro-organismos e imunohistoquímica para identificação dos marcadores RANKL, OPG e Periostina (PRT). As análises foram realizadas de forma descritiva e quantitativa. Dados quantitativos foram submetidos à analise estatística por meio do teste paramétrico ANOVA de uma via e pós-teste de Tukey e dos testes não-paramétricos de qui-quadrado e exato de Fisher, com nível de significância de 5%. Ao final da revisão sistemática da literatura pudemos concluir que não há evidência para estabelecer qual o melhor meio de conservação para dentes avulsionados. Dentre os meios que foram encontrados estão a água de coco, água da torneira, leite de soja, leite integral, solução salina, saliva, própolis, soro fisiológico, solução Euro-Collins, solução salina balanceada de Hanks (HBSS) e Viaspan®. Ainda que esta revisão tenha sido conduzida em modelo animal experimental, a baixa qualidade dos estudos bem como a sua heterogeneidade indicam que a extrapolação para humanos deva ser cautelosa. No estudo experimental em modelo animal, o tratamento de superfície com Denosumab a 60 mg/mL preveniu a anquilose, a reabsorção por substituição e a reabsorção dentária, após 60 dias, comparado com o grupo sem tratamento. A coloração de Brown & Brenn evidenciou uma menor contaminação nos tecidos mineralizados quando do tratamento de superfície com Denosumab, independente da concentração utilizada. Com relação à imunohistoquímica, o tratamento com Denosumab inibiu a síntese de RANKL sem modular OPG. A Periostina foi observada no ligamento periodontal dos dentes reimplantados. Porém, essa marcação estava ausente nas áreas de anquilose, em ambos os períodos experimentais, indicando que durante o processo de anquilose a síntese de periostina é inibida, o que resulta na fusão do osso à superfície radicular. / The treatment of choise for permanent dental avulsion is replantation. However, it is known that the success of the repair after replantation depend especially the extracellular and the storage medium in which is stored the tooth. Accordingly, in order to have success after replantation is necessary that the tooth is replanted immediately and/or to be kept in a medium capable of maintaining the cell´s vitality of the root surface. If that is not possible, treatment of the radicular surface should be done in order to prevent radicular resorption. Thus, the firstly aim was to perfom a systematic review to evaluate the in vivo effectiveness of different storage media for avulsed teeth. So, the second aim of this study is to test the substance as Denosumab, a monoclonal antibody, for the topical treatment of the root surface in order to prevent dental ankylosis and replacement resorption. For this, we used 36 rat incisors rights, extracted and replanted, and divided into: group I, positive control, delayed replantation without root surface treatment; groups II and III , experimental groups, delayed replantation without root surface treatmen with Denosumab 60 mg/mL and 30 mg/mL, respectively, for 10 minutes. The canals were filling with calcium hydroxide and the teeth were replanted. After periods of 15 and 60 days of the replantation, the animals will be euthanized. Then, samples are removed and processed for microscopic analysis. Histological sections were performed, stained with hematoxylin and eosin, to describe the characteristics of the dental surface and the periodontal ligament and to measure the length of ankylosis, replacement resorption and dental resorption by conventional microscopy, and for the measure the area of periodontal ligament, by fluorescence microscopy. Sequential specimens were analyzed by Brown & Brenn, for localization of bacteria; and markek by immunohistochemistryfor RANKL, OPG and Periostin (PRT). The analysis were displayed qualitatively or quantitatively. Data were subjected to statistical analysis by oneway ANOVA and the Tukey post-test and by chi-square and Fisher\'s exact tests. The significance level was set at 5%. The systematic review does not provide enough evidence to determine the best storage medium to achieve successful tooth replantation. This systematic review has identified many storage media that have been used to preserve avulsed teeth, including coconut water, tap water, soy milk, whole milk, saline solution, saliva, propolis, physiologic saline, Euro-Collins solution, HBSS, and Viaspan®. Although this review was conducted in an experimental animal model, a poor quality of the studies as well as their heterogeneity indicates that a human extrapolation should be cautious. In the experimental study in animal model, root surface treatment with Denosumab 60 mg/mL prevented ankylosis, replacement resorption, and tooth resorption, 60 days after replantation, compared with the untreated group. Brown & Brenn staining showed a lower contamination in the mineralized tissues in the Denosumab surface treatment group, regardless of the concentration used. As for immunohistochemistry, Denosumab inhibited the synthesis of RANKL without modulating OPG. Periostin was observed in periodontal ligament of tooth replanted. However, this labeling was absent in the ankylosis areas, in both experimental periods, indicating that during the ankylosis process, the periostin synthesis is inhibited, resulting in the fusion between bone and root surface.
208

材料表面處理技術的創業規劃及經營探討 / A study on the entrepreneurial plan and management for surface treatment of materials

葉信宏, Yeh,shinn horng Unknown Date (has links)
新創企業在創業之初,往往資源不足、訂單未到、客戶關係未建立好、技術及產品未成熟、管理尚未到位,市場不確定等不利因素。所以不管從台灣或大陸的環境來看新創企業,創業之初的三到五年是新創企業最為艱困且風險最高的時段。 因此本研究主要在探討,材料表面處理技術的創業規劃及經營,新創企業如何在創業醞釀階段,就做好創業活動規劃;在草創存活階段,做好存活策略推動,使企業得以存活;在經營維持階段,如何推進經營利潤,並讓企業持續發展下去。使新創企業處於不同階段下,能有效分析、規劃及做好該階段的行動任務,而讓新創企業渡過各個階段的考驗,為本論文的研究目的。 研究結果顯示,在創業醞釀階段,要有創業活動的形成,需要在創業活動前做好分析及規劃。除要有創業的「環境價值機會」出現外,要有能提供顧客價值之「價格」、「品質」、「速度」、「需求滿足」誘因,及具備「技術、產品或服務」、「人或團隊」、「資金」、「客戶關係」等創業關鍵組成。 在草創存活階段,企業需推動存活策略三構面,使企業能順利存活下來,其中與其構面變項有利的連接方向,證明朝向:產品/服務經營模式「訂定得當」、控制資源/開銷「消耗少」、創造利益體/網絡「連結多」,將最有利於新創企業存活的方向。此外,新創企業在草創階段,如所從事的產品或服務之營銷活動,所在的區域、客戶、及市場,在創業之初有很高的不確定性,選擇性或階段性的「集中」(Focus)策略才是正確的戰略。但如從存活策略三構面上做分析,所得到的結果皆為不利的情況,而資源又已先行投入情況下,如擬存活下來,對該項目最好的經營策略就是採取「退縮」(Withdrawal)策略。 而在新創企業在剛經歷草創存活階段後,為能持續性存活下來,需有「經營利潤推進」產生,才得以能維持經營。本論文從經營利潤推進的角度,提出經營維持的四構面做法,包括在創業經營風險構面及成本構面的降低活動;價值構面及收入構面的提升活動。做為在經營維持階段,主要的經營指標。因此,具體落實經營利潤推進的四構面,企業才得以有「利潤」的產生,也唯有利潤的產生,新創企業才得以有機會永續。 關鍵字:新創企業、創業規劃、存活策略、利潤推進、表面處理 創業管理 / A start-up at the beginning often encounters the following challengers: resources are insufficient; the order has not been big enough; customer's relation has not been set up well; the technology and the product is immature; the management has not been put in place yet; the market is uncertain, and so on. No matter the new company is operating in Taiwan or the mainland china, it will face high risk, particularly in the period of 3rd to 5th year after its establishment. Therefore, this research aims to study the entrepreneurial plans and managements for the material surface treatment technology, including how to make a business activity plan well in the entrepreneurial fermentation stage? how to do a better survival strategy promotion in the starting survival stage? and how to become profitable in the management arrangement stage. The purpose to let the new enterprise pass each stage sufferings by effectively analyzing, planning and completing action tasks under the different periods. The findings showed that the company needs to complete the analysis and the plan prior to the activity of entrepreneurship in the entrepreneurial fermentation stage. Besides providing with the opportunities for value added, the start-up needs to provide with “the customer value”, such as “price”, “quality”, “speed”, and “the satisfied demand” to provide, and to possess “the entrepreneurial key element” including “the technology, the product or the service”, “the human or the team”, “the fund”, and “the customer relations”. In the starting survival stage, the enterprise could implement the three key actions of survival strategy to survive smoothly. It is proven that a better survival orientation for a newly created enterprise is to have an appropriate position in product/service or business model, to utilize fewer resources/expenses, and to link with a wider network. In addition, the right strategy for a newly created enterprise in the starting survival stage is the selective or gradual focus strategy, if the marketing activities of product/service have the very high uncertainty at the beginning of the undertaking in the region or the market. The analysis from three key elements of survival strategy obtains result all for disadvantageous situation, but resources already in advance investment situation. The best management strategy is adapted to the strategy of withdrawal. A newly creation enterprise has gone through the starting survival stage, the advancement of operating profit should be produced to last for long enduring survival. The present paper proposed four key elements of management maintenance as a main management target from the advancement's angle of operating profit, which including to reduces the operational risk and cost elements and to increase the operational value and income elements. Therefore, the new enterprise could carry out the four key elements of operating profit advancement to get “the profit”, which would let enterprise have the opportunity to last forever. Keywords:Newly Created Enterprise, Entrepreneurial Plan, Survival Strategy, Profit Advancement, Surface Treatment, Entrepreneurial Management,
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Επεξεργασία υλικών από ψυχρό πλάσμα φθορανθράκων προς παραγωγή μη-ρυπαινόμενων μονωτικών υλικών

Κεφάλα, Ειρήνη 07 June 2013 (has links)
Η μείωση της ρύπανσης των μονωτήρων εξωτερικών χώρων είναι ένα αντικείμενο το οποίο έχει απασχολήσει εκτεταμένα τους μηχανικούς λόγω των απαιτήσεων που υπάρχουν στην αποδοτική λειτουργία των μονωτήρων αυτών. Στην παρούσα διπλωματική δοκιμάστηκαν τέσσερα διαφορετικά υλικά (δυο πολυμερή και δυο κεραμικά) που χρησιμοποιούνται στην κατασκευή τέτοιων μονωτήρων και μελετήθηκε η μεταβολή στην υδροφοβία της επιφάνειάς τους μετά από επεξεργασία αυτών από ψυχρό πλάσμα φθορανθράκων χαμηλής πίεσης. Παράλληλα έγιναν και ηλεκτρικές μετρήσεις σε πλάσμα Ο2 και CF4 προκειμένου να γίνουν γνωστές οι τιμές της τάσης και του ρεύματος κάτω από τις οποίες έγινε η επεξεργασία των επιφανειών. Πιο συγκεκριμένα: • Στο πρώτο κεφάλαιο έγινε μια εισαγωγή στους μονωτήρες εξωτερικών χώρων, κατάταξη αυτών με βάση τη θέση τους ως προς τους ηλεκτροφόρους αγωγούς αλλά και ως προς το υλικό κατασκευής τους. Έγινε επίσης παρουσίαση των επιπτώσεων της ρύπανσης των μονωτήρων αλλά και απαρίθμηση των μεθόδων αντιμετώπισης της. Τέλος, εξηγήθηκε η έννοια της υδροφοβίας και έγινε εισαγωγή στις ιδιότητες του πλάσματος φθορανθράκων. • Στο δεύτερο κεφάλαιο περιγράφηκε αναλυτικά η διάταξη παραγωγής πλάσματος χαμηλής πίεσης καθώς επίσης και η διάταξη μέτρησης γωνιών επαφής. Παρατίθενται φωτογραφίες αλλά και πλήρης περιγραφή όλων των επιμέρους διατάξεων που χρησιμοποιήθηκαν στην παρούσα διπλωματική εργασία. • Στο τρίτο κεφάλαιο παρουσιάστηκαν και αναλύθηκαν τα πειραματικά αποτελέσματα και μετρήσεις (ηλεκτρικές μετρήσεις και μετρήσεις γωνιών επαφής) που συλλέχθηκαν κατά την εκπόνηση της εργασία καθώς επίσης και γραφικές παραστάσεις για την ομαδοποίηση των δεδομένων. • Στο τέταρτο κεφάλαιο καταγράφηκαν τα συμπεράσματα στα οποία οδήγησε η παρούσα διπλωματική. / Reducing pollution in the surface of outdoor insulators is an issue that has occurred and has troubled lots of engineers due to strict requirements that should be met for specific insulators’ proper operation. In the present thesis, four different insulating materials (two polymerics and two ceramics) were tested and the change on their surface hydrophobic properties was studied. Furthermore, electrical measurements in O2 and CF4 plasma were taken so the values of the current and voltage under which this experiment has taken place, would be known. More specific: • In the first chapter, an introduction to outdoor insulators was made. They were classified according to their position regarding the conductors and their construction material. Also, the consequences of pollution and some ways of its control were presented. Lastly, there was explained the concept of hydrophobicity and the properties of fluorocarbon plasma. • In the second chapter, the vacuum system that was used to create low pressure, fluorocarbon plasma is analyzed as well as the device for measuring the contact angles of the samples. This detailed presentation is accompanied by photographs and full analysis of all the individual devices that were used in the present thesis. • In the third chapter, all the experimental results were presented and analyzed. The measurements (electrical and contact angles’) were plotted so that data would appear in groups. • In the forth chapter, all the conclusions of the present thesis were exported.
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Influência do meio de conservação e efeito do tratamento de superfície na anquilose e na reabsorção de tecidos mineralizados após o reimplante de dentes avulsionados / Influence of the storage medium and effect of root surface treatment on ankylosis and resorption of mineralized tissues after tooth replantation

Daniele Lucca Longo 03 July 2017 (has links)
O tratamento preconizado para dentes permanentes avulsionados devido a traumatismos dentários em crianças é o reimplante dental. Entretanto, sabe-se que o sucesso após o reimplante depende, especialmente, do tempo em que o dente permanece fora do alvéolo e do meio de conservação no qual o dente é armazenado. Nesse sentido, para que se tenha sucesso após o reimplante faz-se necessário que o dente seja imediatamente reimplantado e/ou seja mantido em um meio capaz de manter a vitalidade das células da superfície radicular. Se isso não for possível, o tratamento da superfície radicular deverá ser instituído com o objetivo de prevenir a reabsorção radicular. Dessa maneira, esta pesquisa teve como primeiro objetivo avaliar a influência de diferentes meios de conservação para dentes avulsionados, por meio de uma revisão sistemática, com a finalidade de estabelecer se há um consenso sobre o meio mais adequado para conservação capaz de prevenir sequelas como anquilose e reabsorção dentária. A seguir, o segundo objetivo desse estudo foi testar o Denosumab, um anticorpo monoclonal anti-RANKL, como substância para o tratamento tópico da superfície radicular, a fim de evitar a anquilose e a reabsorção dentária por substituição. Para tanto, foram utilizados 36 incisivos superiores direitos de ratos submetidos à extração cirúrgica, manutenção em meio extra-alveolar seco por 60 minutos e posterior reimplante. No grupo I, controle positivo, foi realizado o reimplante tardio sem tratamento de superfície; nos grupos II e III, grupos experimentais, previamente ao reimplante tardio foi realizado o tratamento da superfície radicular com solução de Denosumab a 60 mg/mL e a 30 mg/mL, respectivamente, por 10 minutos. Os canais radiculares dos animais dos três grupos foram preenchidos com pasta à base de hidróxido de cálcio, via retrógrada, e em seguida os dentes foram reimplantados. Decorridos 15 e 60 dias do reimplante, os animais foram submetidos à eutanásia e as peças, contendo dente e osso, foram removidas para o processamento histotécnico. A seguir cortes histológicos foram realizados, corados por hematoxilina e eosina (HE), para descrição das características da superfície dentária e do ligamento periodontal e para mensuração do comprimento (perímetro) da anquilose e/ou reabsorção por substituição e das áreas de reabsorção dentária, em microscopia de luz e, para mensuração da área do ligamento periodontal, em microscopia de fluorescência. Espécimes sequenciais foram analisados por meio de coloração de Brown & Brenn modificada para identificação de micro-organismos e imunohistoquímica para identificação dos marcadores RANKL, OPG e Periostina (PRT). As análises foram realizadas de forma descritiva e quantitativa. Dados quantitativos foram submetidos à analise estatística por meio do teste paramétrico ANOVA de uma via e pós-teste de Tukey e dos testes não-paramétricos de qui-quadrado e exato de Fisher, com nível de significância de 5%. Ao final da revisão sistemática da literatura pudemos concluir que não há evidência para estabelecer qual o melhor meio de conservação para dentes avulsionados. Dentre os meios que foram encontrados estão a água de coco, água da torneira, leite de soja, leite integral, solução salina, saliva, própolis, soro fisiológico, solução Euro-Collins, solução salina balanceada de Hanks (HBSS) e Viaspan®. Ainda que esta revisão tenha sido conduzida em modelo animal experimental, a baixa qualidade dos estudos bem como a sua heterogeneidade indicam que a extrapolação para humanos deva ser cautelosa. No estudo experimental em modelo animal, o tratamento de superfície com Denosumab a 60 mg/mL preveniu a anquilose, a reabsorção por substituição e a reabsorção dentária, após 60 dias, comparado com o grupo sem tratamento. A coloração de Brown & Brenn evidenciou uma menor contaminação nos tecidos mineralizados quando do tratamento de superfície com Denosumab, independente da concentração utilizada. Com relação à imunohistoquímica, o tratamento com Denosumab inibiu a síntese de RANKL sem modular OPG. A Periostina foi observada no ligamento periodontal dos dentes reimplantados. Porém, essa marcação estava ausente nas áreas de anquilose, em ambos os períodos experimentais, indicando que durante o processo de anquilose a síntese de periostina é inibida, o que resulta na fusão do osso à superfície radicular. / The treatment of choise for permanent dental avulsion is replantation. However, it is known that the success of the repair after replantation depend especially the extracellular and the storage medium in which is stored the tooth. Accordingly, in order to have success after replantation is necessary that the tooth is replanted immediately and/or to be kept in a medium capable of maintaining the cell´s vitality of the root surface. If that is not possible, treatment of the radicular surface should be done in order to prevent radicular resorption. Thus, the firstly aim was to perfom a systematic review to evaluate the in vivo effectiveness of different storage media for avulsed teeth. So, the second aim of this study is to test the substance as Denosumab, a monoclonal antibody, for the topical treatment of the root surface in order to prevent dental ankylosis and replacement resorption. For this, we used 36 rat incisors rights, extracted and replanted, and divided into: group I, positive control, delayed replantation without root surface treatment; groups II and III , experimental groups, delayed replantation without root surface treatmen with Denosumab 60 mg/mL and 30 mg/mL, respectively, for 10 minutes. The canals were filling with calcium hydroxide and the teeth were replanted. After periods of 15 and 60 days of the replantation, the animals will be euthanized. Then, samples are removed and processed for microscopic analysis. Histological sections were performed, stained with hematoxylin and eosin, to describe the characteristics of the dental surface and the periodontal ligament and to measure the length of ankylosis, replacement resorption and dental resorption by conventional microscopy, and for the measure the area of periodontal ligament, by fluorescence microscopy. Sequential specimens were analyzed by Brown & Brenn, for localization of bacteria; and markek by immunohistochemistryfor RANKL, OPG and Periostin (PRT). The analysis were displayed qualitatively or quantitatively. Data were subjected to statistical analysis by oneway ANOVA and the Tukey post-test and by chi-square and Fisher\'s exact tests. The significance level was set at 5%. The systematic review does not provide enough evidence to determine the best storage medium to achieve successful tooth replantation. This systematic review has identified many storage media that have been used to preserve avulsed teeth, including coconut water, tap water, soy milk, whole milk, saline solution, saliva, propolis, physiologic saline, Euro-Collins solution, HBSS, and Viaspan®. Although this review was conducted in an experimental animal model, a poor quality of the studies as well as their heterogeneity indicates that a human extrapolation should be cautious. In the experimental study in animal model, root surface treatment with Denosumab 60 mg/mL prevented ankylosis, replacement resorption, and tooth resorption, 60 days after replantation, compared with the untreated group. Brown & Brenn staining showed a lower contamination in the mineralized tissues in the Denosumab surface treatment group, regardless of the concentration used. As for immunohistochemistry, Denosumab inhibited the synthesis of RANKL without modulating OPG. Periostin was observed in periodontal ligament of tooth replanted. However, this labeling was absent in the ankylosis areas, in both experimental periods, indicating that during the ankylosis process, the periostin synthesis is inhibited, resulting in the fusion between bone and root surface.

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