L’hydrogène constitue un vecteur d’énergie très important. En effet, il est abondant à l’état combiné et sa combustion est très énergétique et non polluante. En revanche, le mode de stockage le plus sécurisant de ce gaz explosif c’est dans les métaux sous forme d’hydrure. Parmi ces métaux, le magnésium est l’un des plus prometteurs car il possède une capacité massique de stockage élevée (7,6%), un faible coût et une abondance naturelle. Cependant ses cinétiques de sorption sont lentes et son hydrure MgH2 est très stable et mauvais conducteur. L’objectif de ce travail de thèse est de contribuer à la résolution des points faibles du magnésium, en lui ajoutant des fibres de carbone comme renfort soit par broyage énergétique pour assurer une bonne intimité entre les deux, soit par coulage en bande, une technique qui permet d’orienter les fibres, pour un maximum de conductivité thermique. Nous étions donc intéressés à l’étude des cinétiques d’absorption/désorption où une amélioration a été observée après l’ajout du carbone par broyage. Une étude de la conductivité thermique était encore intéressante où le matériau préparé par coulage en bande, comme prévu, a présenté un très bon résultat. D’autre part, nous avons effectué des tests d’hydrolyse pour la production délocalisée d’hydrogène. Ayant comme problème la formation d’une couche imperméable de Mg(OH)2 en surface qui bloque la réaction, différents paramètres ont été modifiés (pH, T°, taille des particules, US) et cela a donné un impact positif sur le rendement en hydrogène et la cinétique de la réaction. Finalement, deux procédés de déformation plastique sévère i) le laminage et ii) l’ECAP ont été appliqués sur du TiH2 et du MgH2. Ces deux techniques ont présenté un pouvoir de déstabilisation des hydrures et donc une diminution de la température de déshydruration. Ils ont encore montré un comportement différent du broyage mécanique de point de vue microcontrainte et orientation des plans cristallins. / Hydrogen is a very important energy carrier. Indeed, it is abundant in the combined state and its combustion, very energetic, is non-polluting. However, the safest storage mode of this explosive gas is in the metal hydride form. Among metals, magnesium is one of the most promising one because its high mass capacity storage (7. 6%), low cost and natural abundance. However its kinetics of sorption are slow and its hydride MgH2 is very stable and has a poor thermal conductivity. The objective of this thesis is to resolve most of the weaknesses of magnesium by adding carbon fibers as reinforcement using the ball milling process, a way to ensure a good contact between the two, either by tape casting, a technique to help in the fibers’ orientation, for a maximum of thermal conductivity. We were therefore interested in the study of absorption / desorption kinetics, where an improvement was observed after the addition of carbon by grinding. A study of the thermal conductivity was also interesting, and the material prepared by tape casting, as expected, gave a very good result. On the other hand, we performed some hydrolysis’ tests to produce hydrogen. Having the problem of Mg(OH)2 formation on the surface, that blocks the reaction; different parameters were modified (e. G. PH, T°, particle size, U. S. ), which showed a positive impact on the hydrogen yield and reaction kinetics. Finally, two severe plastic deformation methods: i) cold rolling and ii) ECAP were applied to the TiH2 and MgH2 samples. Both techniques showed a destabilizing power of hydrides and therefore a decrease in the temperature of dehydrogenation. They even showed different behaviors than the mechanical grinding from microstrain and planes orientation point of view.

Introdução: o fator de proteção solar (FPS) dos filtros solares é determinado in vivo pela aplicação de uma quantidade padrão de 2mg/cm². Na prática, os usuários aplicam uma quantidade menor e de maneira irregular o que afeta o FPS final. Modelos matemáticos mostram que a reaplicação do fotoprotetor resulta em um aumento de 15-40% na capacidade de proteção à radiação ultravioleta. Objetivos: avaliar se a reaplicação de filtro solar aumenta a quantidade e melhora a regularidade do filme do produto na pele. Métodos: os voluntários selecionados foram solicitados a aplicar um filtro solar padronizado composto por benzofenona 6% (FPS 6) em ambos antebraços previamente lavados com sabonete neutro. Após 30 minutos o fotoprotetor foi reaplicado em um antebraço, selecionado previamente por computador para evitar a influência do lado dominante. Cinco fitas adesivas foram coletadas de duas diferentes áreas de cada antebraço, 30 minutos após a primeira aplicação e 30 minutos após a reaplicação. A concentração de benzofenona foi medida por cromatografia líquida de alta eficiência e a quantidade do filtro estimada por correlação matemática entre a quantidade de benzofenona removida nas fitas e a concentração na formulação. Resultados: um total de 107 voluntários, com idades entre 18 e 35 anos, foram selecionados. Entre eles, 36 participaram da parte prática do estudo (21 mulheres e 15 homens, idade média de 22,6 anos) A mediana da quantidade do filme de filtro solar aplicado à pele com 1 aplicação foi de 0,43mg/cm² (0,17-1,07) e com 2 aplicações foi de 0,95mg/cm² (0,18-1,91) e essa diferença foi considerada estatisticamente significativa (p=0,002). A variação comparando a uniformidade do filme com 1 e 2 aplicações não foi significativa (p=0,423). Conclusões: a reaplicação de filtro solar resulta em uma melhora da quantidade de produto aplicado à pele, refletindo, provavelmente, em uma melhora da proteção à radiação ultravioleta. Contudo, mesmo com a reaplicação a quantidade mediana foi inferior à preconizada (2mg/cm²) e não foi uniforme, confirmando que o fator de proteção real é muito inferior ao estabelecido no rótulo do produto. Os resultados reforçam a recomendação de reaplicar o produto para atingir um melhor nível de fotoproteção. / Background: the sun protection factor (SPF) of sunscreens is determined in vivo by the application of a standard amount of 2mg/cm², under controlled conditions. Individuals usually apply a smaller and irregular amount, compromising the final sun protection. Theoretical models show that sunscreen reapplication results in an increase of 15% to 40% in the UV protection capacity. Objective: to verify how young individuals use the filter and whether its reapplication increases the amount and regularity of the product in the skin, under real conditions. Methods: the selected volunteers were asked to apply a standardized sunscreen with 6 % benzophenone on both forearms. After 30 minutes, the sunscreen was reapplied in one of the forearms. Five tape-strips were collected from 2 different sites in each forearm, 30 minutes after the first application and 30 minutes after reapplication. The concentration of benzophenone was measured by liquid chromatography and the quantity of filter was estimated by calculating the correlation between the amount of benzophenone that was removed by the tapes, and the quantity present in the formulation. Results: A total of 107 volunteers, with ages between 18 and 35 years, were selected. Among them, 36 volunteers (21 female and 15 male, mean age 22.6 years) participated in the practical part of the study. The overall median sunscreen amount was 0,43mg/cm² (0.17–1.07) with 1 application and 0.95mg/cm² (0.18-1.91) with 2 applications, and the difference between sites was significant (p=0,002). The variation comparing the uniformity of the film with 1 and 2 applications was not significant (p=0,423). Conclusion: the reapplication of sunscreen contributes for a better amount of the product in the skin, probably reflecting in a better sun protection. However, even with reapplication, the median amount was less than the recommended one (2mg/cm²) and not homogeneous, confirming that the real level of protection is much lower than the stated SPF of the product. The results support the recommendation for reapplying filters to obtain a more reliable chemical photoprotection.

Introdução: o fator de proteção solar (FPS) dos filtros solares é determinado in vivo pela aplicação de uma quantidade padrão de 2mg/cm². Na prática, os usuários aplicam uma quantidade menor e de maneira irregular o que afeta o FPS final. Modelos matemáticos mostram que a reaplicação do fotoprotetor resulta em um aumento de 15-40% na capacidade de proteção à radiação ultravioleta. Objetivos: avaliar se a reaplicação de filtro solar aumenta a quantidade e melhora a regularidade do filme do produto na pele. Métodos: os voluntários selecionados foram solicitados a aplicar um filtro solar padronizado composto por benzofenona 6% (FPS 6) em ambos antebraços previamente lavados com sabonete neutro. Após 30 minutos o fotoprotetor foi reaplicado em um antebraço, selecionado previamente por computador para evitar a influência do lado dominante. Cinco fitas adesivas foram coletadas de duas diferentes áreas de cada antebraço, 30 minutos após a primeira aplicação e 30 minutos após a reaplicação. A concentração de benzofenona foi medida por cromatografia líquida de alta eficiência e a quantidade do filtro estimada por correlação matemática entre a quantidade de benzofenona removida nas fitas e a concentração na formulação. Resultados: um total de 107 voluntários, com idades entre 18 e 35 anos, foram selecionados. Entre eles, 36 participaram da parte prática do estudo (21 mulheres e 15 homens, idade média de 22,6 anos) A mediana da quantidade do filme de filtro solar aplicado à pele com 1 aplicação foi de 0,43mg/cm² (0,17-1,07) e com 2 aplicações foi de 0,95mg/cm² (0,18-1,91) e essa diferença foi considerada estatisticamente significativa (p=0,002). A variação comparando a uniformidade do filme com 1 e 2 aplicações não foi significativa (p=0,423). Conclusões: a reaplicação de filtro solar resulta em uma melhora da quantidade de produto aplicado à pele, refletindo, provavelmente, em uma melhora da proteção à radiação ultravioleta. Contudo, mesmo com a reaplicação a quantidade mediana foi inferior à preconizada (2mg/cm²) e não foi uniforme, confirmando que o fator de proteção real é muito inferior ao estabelecido no rótulo do produto. Os resultados reforçam a recomendação de reaplicar o produto para atingir um melhor nível de fotoproteção. / Background: the sun protection factor (SPF) of sunscreens is determined in vivo by the application of a standard amount of 2mg/cm², under controlled conditions. Individuals usually apply a smaller and irregular amount, compromising the final sun protection. Theoretical models show that sunscreen reapplication results in an increase of 15% to 40% in the UV protection capacity. Objective: to verify how young individuals use the filter and whether its reapplication increases the amount and regularity of the product in the skin, under real conditions. Methods: the selected volunteers were asked to apply a standardized sunscreen with 6 % benzophenone on both forearms. After 30 minutes, the sunscreen was reapplied in one of the forearms. Five tape-strips were collected from 2 different sites in each forearm, 30 minutes after the first application and 30 minutes after reapplication. The concentration of benzophenone was measured by liquid chromatography and the quantity of filter was estimated by calculating the correlation between the amount of benzophenone that was removed by the tapes, and the quantity present in the formulation. Results: A total of 107 volunteers, with ages between 18 and 35 years, were selected. Among them, 36 volunteers (21 female and 15 male, mean age 22.6 years) participated in the practical part of the study. The overall median sunscreen amount was 0,43mg/cm² (0.17–1.07) with 1 application and 0.95mg/cm² (0.18-1.91) with 2 applications, and the difference between sites was significant (p=0,002). The variation comparing the uniformity of the film with 1 and 2 applications was not significant (p=0,423). Conclusion: the reapplication of sunscreen contributes for a better amount of the product in the skin, probably reflecting in a better sun protection. However, even with reapplication, the median amount was less than the recommended one (2mg/cm²) and not homogeneous, confirming that the real level of protection is much lower than the stated SPF of the product. The results support the recommendation for reapplying filters to obtain a more reliable chemical photoprotection.

Les mètres rubans sont utilisés comme dispositif de déploiement car ils sont légers, compacts, se déploient de manière autonome et ont une capacité d'auto-blocage en position déployée. Ces structures élancées de forme cylindrique présentent un comportement complexe avec formation de plis localisés. Leur modélisation est donc difficile : bien que des modèles de poutre à section flexible (RFleXS) aient été développés. Les travaux réalisés consistent à développer des outils numériques d'aide au dimensionnement de structures déployées par des rubans. Un modèle RFleXS adimensionné dédié aux rubans peu profonds est introduit et analysé, mettant en évidence des liens avec le modèle de barre d'Ericksen régularisé. Ces liens expliquent la formation de plis et caractérisent les trois zones constitutives d'un pli. On détermine de façon analytique le nombre et la position des points de bifurcation des branches de solution obtenues pour un essai de flexion pure d'un ruban. Un enrichissement de la cinématique de section est intégré dans les modèles RFleXS. Les simulations de flexion de ruban montrent alors une bonne corrélation avec les modèles de coque. Une nouvelle formulation des modèles RFleXS est implémentée et conduisant au développement de deux outils numériques : un code de calcul par éléments finis complet et un élément à deux noeuds intégré dans un code commercial. Des essais de flexion réalisés sur des rubans composites viennent compléter ces travaux afin de confronter les simulations numériques à des essais réels. Bien que des écarts soient observés, le comportement global du ruban est bien retranscrit par les modèles de poutre à section flexible. / Due to their lightness, compactness, their autonomous deployment and their ability to self-locking while deployed, tape-springs are considered to deploy structures. These slender and cylindrical structures highlight a complex behaviour because of the formation of localised folds. Tape-springs are then difficult to model but a rod model with flexible cross-section (RFleXS) has been developed in order to characterise the tape-spring behaviour.The purpose of this PhD was to develop numerical tools dedicated to design structures deployed by tape-spings. A dimensionless form of the RFleXS model dedicated to shallow tape spring has been developed and links with a regularised Ericksen's bar have been made. These links help to explain folds creation and to determine characteristics of the three constitutive areas of a fold. Analysis of the dimensionless model leads to determine the finite number and the position of bifurcation points for the pure bending of a tape-spring. The cross-section kinematic is enriched; simulations of bending tests then show a good correlation with shell models. A new implementation of RFleXS models is introduced, leading to the creation of two numerical tools: a full finite element software and a one-dimensional element with two nodes incorporated in Abaqus. Some bending experiments have been performed in order to compare simulations with measured data. Even if discrepancies are observed, these comparisons show that the tape-spring overall behaviour is well predicted by rod models with flexible cross-section.

Orientador: Antonio Carlos de Moraes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Educação Física / Made available in DSpace on 2018-08-16T13:36:04Z (GMT). No. of bitstreams: 1 Moura_MelissaLuiza_M.pdf: 5391341 bytes, checksum: 1aaa11b5c3366a4040a0fe7a901723f9 (MD5) Previous issue date: 2010 / Resumo: A síndrome tensional cervical (STC) é a tensão no músculo trapézio decorrente de atividades repetitivas e aumento da carga muscular estática associados à postura inadequada da cintura escapular. O objetivo deste estudo foi comparar a eficácia da bandagem funcional (BF) e da corrente interferencial (CI) no alívio da dor da STC através da escala visual analógica da dor (EVA) e, confrontar as respostas dos sinais eletromiográficos do músculo trapézio descendente antes e após cada intervenção. 30 voluntárias do sexo feminino, com hipótese diagnóstica de STC foram avaliadas, com média de idade, estatura e massa corpórea de 28,2 anos, 1,61 m e 59,2 kg, respectivamente. Foram divididas em três grupos, com 10 indivíduos cada: Grupo Bandagem Funcional (GBF) - intervenção de 24 horas com bandagem funcional no músculo trapézio superior; Grupo Corrente Interferencial (GCI) - três dias consecutivos (GCI dia 1, 2 e 3) com intervenção de eletroterapia de 30 minutos cada dia; Grupo Controle (GC) - 30 minutos em repouso. Antes e após as intervenções foram mensuradas as respostas subjetivas da dor através da EVA e, as respostas da atividade elétrica da musculatura. Utilizou-se estatística descritiva para caracterização da amostra, apresentando valores referentes às variáveis selecionadas no estudo. Para os valores expressos em RMS e FM foi utilizado o teste de normalidade Shapiro-Wilk. Utilizou-se a análise de variância (ANOVA) one way, para análise entre os tratamentos no momento após. O teste t foi utilizado para análise intragrupos, comparando antes e após de cada grupo, e antes do GCI dia 1 com o após do GCI dia 3. Para a análise da EVA foi utilizado o teste de normalidade Shapiro-Wilk. Para a comparação das variações da EVA (antes e após as intervenções) utilizou-se o teste não paramétrico de Mann Whitney e quando normal, teste t. O nível de significância adotado foi de 5%. Os valores subjetivos da dor indicados pelas voluntárias através da EVA antes de iniciar o teste, com ou sem intervenção, foram maiores do que após o mesmo, indicando um quadro álgico doloroso. A variação percentual entre antes e após a intervenção da dor foi significativamente maior em GBF (70,75%) e GCI dia 3 (81,45%), em relação ao GC (5,83%) (p<0,05), representando diminuição significativa da dor com a intervenção. Já quanto à variação eletromiográfica em RMS e em FM não apresentou diferença estatisticamente significativa em nenhuma intervenção. Os resultados demonstram que a utilização de intervenções como BF e/ou CI em procedimentos fisioterapêuticos são alternativas igualmente eficazes para diminuição da percepção subjetiva da dor. Já através da EMG há aumento no recrutamento muscular para exercer contração isométrica voluntária máxima após intervenção de ambos os recursos avaliados. / Abstract: Cervical tension syndrome (CTS) is the tension in the trapezius muscle due to repetitive activities and increased static muscle load associated with bad posture of the shoulder girdle. The aim of this study was to compare the effectiveness of taping (BF) and interferential current (IC) in relieving the pain of CTS by the visual analogue scale (VAS), and compare the electromyographic responses (EMG) of the upper trapezius muscle before and after each intervention. 30 female volunteers with the diagnosis of CTS were evaluated, mean age, height and body mass index of 28.2 years, 1.61 m and 59.2 kg, respectively. Were divided into three groups, with 10 subjects each: Group Taping (GBF) - 24-hours of taping intervention on upper trapezius muscle, Group Interferential Current (GCI) - three consecutive days (GCI days 1, 2 and 3) with 30 minutes each day of electrotherapy intervention; Control Group (GC) - 30 minutes lying. Before and after the interventions were measured the subjective responses of pain by VAS, and the responses of the electrical activity of muscles. We used descriptive statistics to characterize the sample, with values on the variables selected in this study. The values expressed in EMG was used the normality test Shapiro-Wilk. We used analysis of variance (ANOVA) one way for analysis between treatments at the time after it. The t test was used for intragroup analysis, comparing before and after each group, and before the first day with the GCI with the GCI after the third day. For the analysis of VAS was used the normality test Shapiro-Wilk. For comparison of changes in VAS (before and after the interventions) used the Mann Whitney non parametric test and when normal, t test. The level of significance was 5%. Subjective values of pain indicated by the volunteers through the VAS before starting the test, with or without intervention, were higher than after the same, indicating painful. The percentage change between before and after the intervention of pain was significantly higher in the GBF (70.75%) and GCI day 3 (81.45%) compared to CG (5.83%) (p <0.05), representing a significant decrease in pain with the intervention. For the EMG variation in RMS and FM the statistics were not significant in any intervention. The results demonstrate that the use of interventions such as BF and/or IC in physical therapy procedures are equals effective alternative to reduce the subjective perception of pain. Already there is an increase over the EMG of muscle recruitment to exert maximal voluntary isometric contraction. / Mestrado / Ciencia do Desporto / Mestre em Educação Física

This research comprises an experimental and theoretical study on convective boiling inside tubes containing twisted-tape inserts. The demand for more compact and efficient thermal systems, in which the heat exchangers plays an important role, has led to the development and use of various heat transfer enhancement techniques. Among them twisted-tape insert as a swirl flow device is one of the most used. Twisted-tape inserts have been used for over more than one century ago as a technique of heat transfer enhancement applied to heat exchangers. However, the heat transfer augmentation comes together with pressure drop increment, impacting the pumping power and, consequently, the system efficiency. Moreover, until now it is not clear, the operational conditions under which the heat transfer coefficient augmentation by the use of twisted-tape inserts overcomes pressure drop penalty. In the present study, initially, extensive investigations of the literature concerning convective boiling inside plain tubes with and without twisted-tape inserts were performed. This literature review covers pressure drop, heat transfer coefficient and the leading frictional pressure drop gradient and heat transfer coefficient predictive methods during convective boiling inside tubes with and without twisted-tape inserts. Then, pressure drop and heat transfer coefficient results acquired in the present study were obtained in an experimental apparatus of 12.7 and 15.9 mm ID tubes during flow boiling of R134a for twisted-tape ratios of 3, 4, 9, 14 and tubes without inserts, mass velocities ranging from 75 to 200 kg/m2 s, saturation temperatures of 5 and 15°C and heat fluxes of 5 and 10 kW/m2. The experimental results were parametrically analyzed and compared against the predictive methods from literature. An analysis of the enhancement of the heat transfer coefficient and the pressure drop penalty is presented. Heat transfer coefficient increments up to 45% keeping the same pumping power and pressure drop penalty of about 35% were obtained by using twisted-tape relative to tubes without inserts. Additionally, through comparison of the present study experimental results with the predictive methods from the literature for heat transfer coefficient during two-phase flow inside tube containing twisted-tape inserts, it was verified that non of these methods predict satisfactory well the experimental results. However, a new method was develop for predicting the heat transfer coefficient during flow boiling inside tubes containing twisted-tape inserts based on the experimental results obtained in the present study. The predictive method takes into account the physical picture of the swirl flow phenomenon by including swirl flow effects promoted by the twisted-tape inserts. The proposed method predicts satisfactorily well the data obtained in the present study, predicting 89.1% of the experimental data within an error band of ± 30% and absolute mean deviation of 15.7%. / A presente pesquisa trata-se de um estudo teórico e experimental sobre a ebulição convectiva no interior de tubos com fitas retorcidas. A crescente demanda por sistemas térmicos mais compactos e eficientes, nos quais os trocadores de calor apresentam elevada relevância, tem motivado o desenvolvimento de inúmeras técnicas de intensificação de troca de calor, sendo que a utilização de fitas retorcidas é uma das técnicas mais adotadas. Fitas retorcidas são utilizadas como técnicas de intensificação de troca de calor há mais de um século. Entretanto o incremento da transferência de calor é acompanhado do aumento da perda de pressão, que por sua vez implica em aumento da potência de bombeamento, e consequentemente afeta a eficiência global do sistema. Adicionalmente, até os dias de hoje não há consenso sobre as condições operacionais em que o ganho com o incremento do coeficiente de transferência de calor é superior à perda devido ao aumento da perda de pressão. Neste estudo, inicialmente foi realizada uma extensa revisão da literatura sobre a ebulição convectiva no interior de tubos com e sem fitas retorcidas. Esta revisão aborda aspectos relacionados à perda de pressão e ao coeficiente de transferência de calor, juntamente com os métodos de previsão destes parâmetros. Foram realizados experimentos para determinação experimental de perda de pressão e coeficiente de transferência de calor, em aparato experimental contando com tubos horizontais com diâmetros internos iguais a 12,7 e 15,9 mm, para escoamento bifásico de R134a, razões de retorcimento iguais a 3, 4, 9, 14 e tubo sem fita, velocidades mássicas entre 75 e 200 kg/m²s, temperaturas de saturação iguais a 5 e 15°C, e fluxo de calor iguais a 5 e 10 kW/m². Os resultados experimentais foram analisados e comparados com estimativas segundo métodos disponíveis na literatura. Uma análise do aumento do coeficiente de transferência de calor e da perda de pressão friccional é apresentada. Foram verificados incrementos do coeficiente de transferência de calor de até 45% para a mesma potência de bombeamento, e aumento de perda de pressão de aproximadamente 35% para tubos com fitas retorcidas em relação aos tubos sem fita. Adicionalmente, através da comparação dos resultados experimentais com os métodos de previsão para coeficiente de transferência de calor, foi verificado que nenhuma metodologia apresentava previsões satisfatórias dos resultados. Portanto um novo método para previsão do coeficiente de transferência de calor durante ebulição convectiva no interior de tubos com fitas retorcidas foi desenvolvido com base nos resultados experimentais obtidos durante o presente estudo. O método proposto é função de parâmetros geométricos e do escoamento, e também de parâmetros físicos do escoamento rotacional induzido pela fita. A metodologia desenvolvida apresenta previsões satisfatórias dos resultados experimentais, prevendo 89,1% dos resultados experimentais com erro inferior a ± 30% e erro médio absoluto igual a 15,7%.

Reports and consultative documents published at national level since about 1980 have indicated that British Industry must look to modern technology and also educate and train its workers on a 'broad base', with an 'integrated' approach. Traditionally, and still very much the mode of operation, teaching has been confined within subject boundaries. A research group was established by Professor Bajpai consisting of the author, Mr Rod Bond (Burleigh Community College, Loughborough) and a few others working overseas to investigate a teaching strategy based on an interrelated approach to teaching mathematics. Measurement was chosen as the first topic of investigation using this approach which then formed the basis for further research undertaken by the two research workers of the group whose work is reported in the form of two theses. This thesis aims to show that mathematics is naturally related to science and technology in industrial practice and that when taught in an interrelated way it would be more interesting and have more relevance to real applications in technology-based employment at craft and technician levels. To help establish the case experiments carried out by the author are referred to; these include a few case studies, a questionnaire survey and results analysed from more than five hundred basic mathematics tests. The various kinds of mathematics taught in further education are described and compared with mathematics in a practical context as seen from a case study within an engineering training school. Next a survey of mathematics at work shows that, like the training school, there is a task associated with the mathematics which is also related to science or technology or both. Another case study in the pharmaceutical industry lends further support to the way mathematics is used in industry. Much of the mathematics also seems to be basic and used in association with measurement and a particular task. It was decided by the research group that a tape/slide programme on measurement for students and educators should be developed by the author and tested in different situations. Teaching modules on relevant mathematical topics based on the interrelated approach were constructed for students with strong support from industry in the form of materials and advice. Testing of these modules, in their original and revised forms after feedback, is described. These trials were also carried out in other establishments. Modules based upon the interrelated approach developed by the author formed a basis for promoting the underlying philosophy behind this approach. These were presented to educators in in-service training and staff development programmes in the north western region of the UK with success. Observations and conclusions drawn clearly indicate that this type of method makes mathematics more interesting and relevant for students of different abilities and backgrounds. Finally pointers are given in the thesis as to the wider use and promotion of this approach for teaching mathematics in further education.

Denna rapport beskriver arbetet med att konstruera utrustning för att strimla, tvinna och fixera en flerskiktsfilm i form av reflextejp med avsikten att tillverka garn av den strimlade tejpen där garnet slutligen stickas och vävs till tyger. Avsikten är inte att utveckla reflexgarn eftersom existerande metoder finns för detta, utan att undersöka om garntillverkning från filmmaterial, eller i en förlängning, andra tvådimensionella material lämpar sig för garnproduktion. Om metoden går att utveckla till kostnadseffektiva, industriella processer kan den exempelvis användas för återvinning av textilier i steget innan konsumentnivå. Överproduktion och tyger med fabrikationsfel inom textilindustrin skulle hypotetiskt kunna strimlas till remsor som tvinnas till relativt grova garner i mekaniska processer. En fördel är att materialblandningar och tillsatta additiv som normaltsett försvårar återvinning inte behöver beaktas. Ett annat tänkbart användningsområde är att råvaror som inte är lämpliga till fibertillverkning kan användas förtextilproduktion. Cellulosabaserat material som används till papperstillverkning där papperet sedan strimlas och tvinnas till garner är ett relativt nytt exempel på garnproduktion från tvådimensionell struktur som just nu är under utveckling. De konstruktioner som tillverkades för strimling, tvinning och fixering fungerade för att producera garner som gick att virka, sticka och väva med. En avgörandefaktor för garnkvaliteten var vilken slags polymer som reflextejpens lim var uppbyggd av. Polyuretan visade sig ge det mest användbara garnet och drygt tvåhundrameter garn av detta material tillverkades under arbetet. De processer och metoder som utvecklats är att betrakta som initiala steg, men är uppskalningsbara till kontinuerliga tillverkningsmetoder i industriell produktion. / This report describes the work of designing equipment for shredding, twisting and heat fixate a multilayer film in the form of reflective tape. The intention is to produce yarn of the shredded and twisted tape, where the yarn is finally knitted and woven into fabrics. The intention is not to develop reflex yarns because existing methods exists for this, but to investigate whether yarn production from film materials, or in an extension, other two-dimensional materials are suitable for yarn production. For example, if the method can be developed into cost-effective industrial processes, it can be used for textile recycling in the pre-consumer stage. Overproduction in the textile industry and fabrics with defects could hypothetically be shredded into strips that are twisted into relatively coarse yarns in mechanical processes. One advantage is that material mixtures and additives which normally make recycling difficult need not be taken into account. Another conceivable area of application is that raw materials which are not suitable for fiber production can be used for textile production. Cellulose-based material used for paper where the paper is shredded and twisted into yarns is a relatively new example of yarn production from a two-dimensional structure that is currently under development. The constructions made for shredding, twisting and heat fixation worked to produce yarns that could be transformed into fabrics. A decisive factor for the yarn quality was the kind of polymer on which the tapes adhesive film was made from. Polyurethane was found to provide the most useful yarn and more than two hundred meters of yarn were made from this material during the work. The processes and methods that have been developed are considered initial steps, but are scalable to continuous manufacturing methods in industrial production.

Bearing currents are not all the same. Under certain circumstances and special use cases classic bearing insulations are not sufficient anymore to prevent bearing currents due to the operation of frequency converters. Additional corrective measures have to be implemented to reduce the source of bearing currents the common mode current. The usage of nanocrystalline tape wound cores shows high effectiveness. As part of a big field study with more than 50 large drive trains in the primary industry, the damaging mechanics of bearing currents are examined under real conditions. Of exceptional high interest is the influence of disturbances which can hardly be simulated in the laboratory. Additional to the shielded motor cable parallel installed functional potential equalization cables applied multiple times have almost no effect in regard to reducing the bearing current. With an optimal installed functional potential equalization system more than 95 percent of the common mode current can flow back through the motor cable shield to the converter. The disturbance impact in the field can influence the voltage over the bearing that breakthroughs are favored but also reduced.

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