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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.
1

Bio-Mag-MEMS autonomes basés sur des aimants permanents

Zanini, Luiz 18 February 2013 (has links) (PDF)
Les micro et nano billes magnétiques sont de plus en plus utilisées en Biologie et en Médecine, pour une large gamme d'applications. Plusieurs applications utilisent le piégeage et le guidage de ces billes sous l'effet d'un champ et d'un gradient de champ magnétique.Dans la plupart des applications le champ magnétique est macroscopique, créé par un aimant ou un électro-aimant. L'intégration plus poussée est souvent envisagée, dans les articles scientifiques, par des micro bobines ou par des éléments magnétiques doux. Ceux-ci doivent alors être polarisés par un champ externe (de nouveau, un électroaimant ou un aimant). Les micro-aimants mis au point à l'Institut Néel permettent d'obtenir les mêmes inductions que les meilleurs aimants du marché et, par conséquent, de par la réduction d'échelle, des gradients de champ intenses. Ils sont, de plus, favorables à l'autonomie et àla stabilité du système. Le défi est de produire de bonnes couches magnétiques avec des dimensions de l'ordre de 1 à 100 μm et de les intégrer à des Bio-Mag-MEMS.Le dépôt physique par phase vapeur (pulvérisation cathodique triode) est utilisé pour le dépôt de ces aimants de haute qualité, en couche épaisse, et à base de terres-rares. Dans le but d'optimiser les gradients latéraux des champs magnétiques, trois techniques ont été développées:* Le topographic patterning, dans lequel une couche est structurée géométriquement,soit par dépôt sur un substrat pré-gravé, soit par gravure humide après le dépôt.* Le thermo-magnetic patterning, qui exploite la dépendance thermique de la coercivité pour réorienter localement l'aimantation de la couche.* Le micro magnetic imprinting, qui consiste à organiser des particules magnétiques à l'aide des aimants mentionnés ci-dessus et, ensuite, de les noyer dans une couche polymérique.Les micro-aimants présentent l'avantage, majeur pour un microsystème, d'être autonomes. Ils ne nécessitent pas de source externe de champ magnétique, ni d'alimentation électrique. Lors de ces travaux, nous développons des prototypes de microsystèmes fluidiques autonomes basés sur des réseaux de micro-aimants. En premier lieu, la capture par attraction et le positionnement controllé, en utilisant des particules super paramagnétiques comme modèle. Puis, l'étude de phénomènes d'endocytose à l'aide d'éléments biologiques marqués magnétiquement. Dans le but de passer à l'intégration des systèmes, des canaux microfluidiques sont développes sur les réseaux magnétiques. Des particules magnétiques etnon-magnétiques sont introduites dans les canaux et leur positionnement, guidage et tri sont réalisés. L'analyse des solutions triées indique une haute efficacité du système.Les résultats obtenus lors du développement de ces micro-sources de champ magnétiques et de leur intégration dans des microsystèmes, ainsi que la manipulation et tri de particules,démontrent le grand potentiel de ces recherches pour des applications grand public à des systèmes biologiques et médicaux. De plus, la biocompatibilité et l'autonomie de ces systèmespermettent leur utilisation dans des microsystèmes d'analyse totale (μTAS), des systèmespoint-of-care (POC) et des implants biomédicaux, potentiellement jetables et bas coût.
2

Structures magnétiques et micro-systèmes pour applications biologiques / Magnetic structures and micro-systems for biological applications

Zanini, Luiz 18 February 2013 (has links)
The range of applications for magnetic micro- and nano-particles is constantlyexpanding, in particular in medicine and biology. A number of applications involve particletrapping and deviation under the effect of a magnetic field and field gradient. In mostpublications, the required magnetic fields are produced either using soft magnetic elementspolarized by an external magnetic field, electromagnets or bulk permanent magnets.Micromagnets produce high fields and favor autonomy and stability while downscalingleads to an increase of field gradients. The challenge is to produce good quality, hardmagnetic films in the range of 1 to 100 μm both in thickness and lateral dimensions and tointegrate them into a Bio-Mag-MEMS.Physical vapor deposition (triode sputtering) is used to prepare high quality rare earthmagnets in thick film form. In order to obtain field gradients in the lateral directions, threetechniques have been developed:• Topographic patterning, in which the film itself is patterned either by sputtering ontopre-etched substrates or by etching the magnetic film.• Thermo-magnetic patterning, which exploits the temperature dependance of coercivityto locally reorient the magnetization.• Micro magnetic imprinting, which consists of organizing magnetic powder with the aidof the above-cited magnets, then embedding the powder into a polymeric matrix.Such micro-magnets are autonomous, having no requirements for a cumbersome externalfield source nor power supply.Here we demonstrate the potential to develop autonomous devices based on micromagnetarrays. Controlled positioning using superparamagnetic particles as a model is shown at first.Then, the magnet arrays are used to study endocytic processes using magnetically labelledbiological elements.In a step towards device integration, microfluidic channels are produced above themagnet arrays. Magnetic and non-magnetic particles are pumped through the devices andprecise positioning, as well as guiding and sorting are performed. High purity is obtained inthe sorted solutions.The good results obtained in the development of micromagnetic flux sources, integrationinto microdevices and particle/cell handling and sorting indicate the high potential of thiswork for actual biological and medical applications. Moreover, the biocompatibility andautonomy of such devices allow their use in micro-total-analysis systems, point-of-care orimplantable devices. / Les micro et nano billes magnétiques sont de plus en plus utilisées en Biologie et enMédecine, pour une large gamme d’applications. Plusieurs applications utilisent le piégeageet le guidage de ces billes sous l’effet d’un champ et d’un gradient de champ magnétique.Dans la plupart des applications le champ magnétique est macroscopique, créé par un aimantou un électro-aimant. L’intégration plus poussée est souvent envisagée, dans les articlesscientifiques, par des microbobines ou par des éléments magnétiques doux. Ceux-ci doiventalors être polarisés par un champ externe (de nouveau, un électroaimant ou un aimant).Les micro-aimants mis au point à l’Institut Néel permettent d’obtenir les mêmesinductions que les meilleurs aimants du marché et, par conséquent, de par la réductiond’échelle, des gradients de champ intenses. Ils sont, de plus, favorables à l’autonomie et àla stabilité du système. Le défi est de produire de bonnes couches magnétiques avec desdimensions de l’ordre de 1 à 100 μm et de les intégrer à des Bio-Mag-MEMS.Le dépôt physique par phase vapeur (pulvérisation cathodique triode) est utilisé pourle dépôt de ces aimants de haute qualité, en couche épaisse, et à base de terres-rares. Dansle but d’optimiser les gradients latéraux des champs magnétiques, trois techniques ont étédéveloppées:• Le topographic patterning, dans lequel une couche est structurée géométriquement,soit par dépôt sur un substrat pré-gravé, soit par gravure humide après le dépôt.• Le thermo-magnetic patterning, qui exploite la dépendance thermique de la coercivitépour réorienter localement l’aimantation de la couche.• Le micro magnetic imprinting, qui consiste à organiser des particules magnétiquesà l’aide des aimants mentionnés ci-dessus et, ensuite, de les noyer dans une couchepolymérique.Les micro-aimants présentent l’avantage, majeur pour un microsystème, d’êtreautonomes. Ils ne nécessitent pas de source externe de champ magnétique, ni d’alimentationélectrique. Lors de ces travaux, nous développons des prototypes de microsystèmes fluidiquesautonomes basés sur des réseaux de micro-aimants. En premier lieu, la capture parattraction et le positionnement controllé, en utilisant des particules superparamagnétiquescomme modèle. Puis, l’étude de phénomènes d’endocytose à l’aide d’éléments biologiquesmarqués magnétiquement. Dans le but de passer à l’intégration des systèmes, des canauxmicrofluidiques sont développes sur les réseaux magnétiques. Des particules magnétiques etnon-magnétiques sont introduites dans les canaux et leur positionnement, guidage et tri sontréalisés. L’analyse des solutions triées indique une haute efficacité du système.Les résultats obtenus lors du développement de ces micro-sources de champ magnétiqueset de leur intégration dans des microsystèmes, ainsi que la manipulation et tri de particules,démontrent le grand potentiel de ces recherches pour des applications grand public à dessystèmes biologiques et médicaux. De plus, la biocompatibilité et l’autonomie de ces systèmespermettent leur utilisation dans des microsystèmes d’analyse totale (μTAS), des systèmespoint-of-care (POC) et des implants biomédicaux, potentiellement jetables et bas coût.
3

Etude de l’application de champs électriques pulsés sur des microalgues en vue de l’extraction de lipides neutres. / Study of the application of pulsed electric fields (PEF) on microalgae for the extraction of neutral lipids.

Bodenes, Pierre 10 May 2017 (has links)
Les microalgues, de par leur diversité, peuvent offrir une multiplicité de molécules bio-sourcées pour des applications variées (alimentation, énergie, santé etc…). Cependant, la production de biodiesel à partir de microalgues, désignée comme la 3e génération de biocarburant, nécessite encore une optimisation lors de l’étape de culture de la biomasse ou lors de l’extraction de l’huile pour que le procédé soit énergétiquement viable. Parmi les voies d’amélioration, l’application de champs électriques pulsés (PEF) en prétraitement à la biomasse pourrait améliorer la rentabilité énergétique du procédé d’extraction de lipides. Ce procédé appliqué aux microalgues est étudié dans le contexte d’une collaboration entre le laboratoire SATIE de l’ENS Cachan Paris Saclay et le laboratoire LGPM de Paris Saclay.Un microsystème d’électroporation a été conçu afin d’étudier in situ l’impact des champs électriques pulsés sur les cellules de microalgue, Chlamydomonas reinhardtii chargées en lipides. Parmi les principaux résultats du projet, l’étude énergétique du procédé a montré que les impulsions de très courte durée (5 µs) sont les moins énergivores. Associées à un champ électrique de 4.5 kV/cm, ces impulsions entrainent une perméabilisation réversible (80 % de cellules atteintes) de quelques secondes tandis qu’un champ de 7 kV/cm entraine un effet irréversible. Après ce prétraitement, les algues sont ensuite mélangées à de l’hexane afin d’évaluer si les lipides sont extraits plus facilement de la cellule. / Microalgae offer a multiplicity of applications for the production of bio-sourced compounds such as proteins, pigments, sugars and oils. However, the energy spent for algae culture and lipid extraction hinder the energetic viability of the process for the production of biofuel derived from algae oils. Among possible improvements, pulsed electric fields (PEF) may be used as a pre-treatment to extract valuable compounds from microalgae and making the process less energy demanding.This project started with a collaboration between the team of bio-micro-systems Biomis, laboratory SATIE, with the team of bio-process engineering laboratory LGPM to study in situ the effects of PEF on microalgae.First, a energetic study is performed in a micro-system specially built for this project to characterize in situ, the effect of various treatment parameters (pulse duration / electric field) on Chlamydomonas reinhardtii cells with high lipid content.Among the outputs of this study, an energetic optimization of PEF conditions shows that a high level of permeability and low energy consumption are obtained when using short pulses of 5 µs. Associated with an electric field of 4.5 kV/cm, the pores are reversible (80% of the cells) during few seconds, and with a field of 7 kV/cm or higher, the permeabilization is irreversible. Afterwards, this PEFpre-treatment is associated with solvent mixing (hexane) to evaluate if lipid extraction is improved.
4

Análise teórica-experimental do desempenho térmico de micro tubos de calor / A theoretical and experimental study on thermal performance of micro heat pipes

Ilvandro Luiz Souza Sueth Júnior 26 October 2018 (has links)
O objetivo deste trabalho consiste na análise teórica e experimental do desempenho térmico de dois arranjos de micro tubos de calor. Os arranjos diferem entre si pelo material base de fabricação, que são Acrilonitrila Butadieno Estireno (ABS) e latão, pelo número de canais e pelas dimensões. O fluido de trabalho utilizado foi R134a. A literatura indica micro tubos de calor como soluções proeminentes e de destaque para resfriamento de micro sistemas. Estes dispositivos podem ser adaptados a diferentes condições térmicas através da mudança de fluidos de trabalho, geometrias e materiais base do trocador. O estudo teórico foi baseado no modelo de circuitos térmicos proposto no presente trabalho, que visa calcular indicadores de desempenho térmico, sendo condutividade térmica efetiva e resistência térmica equivalente dos micro tubos de calor a partir das temperaturas obtidas experimentalmente. O estudo experimental foi baseado em obter distribuições de temperaturas dos dispositivos propostos sob diferentes condições de trabalho, variando-se a fração de enchimento de fluido de trabalho, inclinação e temperatura do condensador. Os resultados obtidos para o arranjo de micro tubos de calor em latão demonstrou uma razão de aumento de até 1482% na capacidade de transporte de calor, enquanto que o arranjo de micro tubos de calor em ABS apresentou uma razão de aumento de 247%. Os melhores desempenhos de ambos os casos foram observados para ângulos positivos com baixas frações de enchimento. / The purpose of this work is the theoretical and experimental study on the thermal performance of two micro heat pipes arrays. The differences between the arrays are the base substrate, which are Acrylonitrile Butadiene Styrene (ABS) and brass, the number of channels and their dimensions. The working fluid used was R134a. Previous works indicate micro heat pipes as prominent solutions for the cooling of micro systems. These devices can be adapted to different thermal conditions by changing the working fluids, geometries and base materials of the heat exchanger. The theoretical study was based on the thermal circuits model presented in this work, that aims on computing thermal performance indicators, such as the effective thermal conductivities and the equivalent thermal resistances of the micro heat pipes from the temperatures obtained experimentally. The experimental study was based on obtaining temperature distributions of the micro heat pipes under different working conditions, by varying the working fluid filling ratio, tilt angle and the temperature of the cooling water at the condenser. The results obtained for the brass micro heat pipe array showed a performance ratio increase up to 1482% in heat transfer capacity, while the ABS micro heat pipe array showed a performance ratio increase of 247%. The best performance for both cases were observed for positive tilt angles with low working fluid filling ratios.
5

Análise teórica-experimental do desempenho térmico de micro tubos de calor / A theoretical and experimental study on thermal performance of micro heat pipes

Sueth Júnior, Ilvandro Luiz Souza 26 October 2018 (has links)
O objetivo deste trabalho consiste na análise teórica e experimental do desempenho térmico de dois arranjos de micro tubos de calor. Os arranjos diferem entre si pelo material base de fabricação, que são Acrilonitrila Butadieno Estireno (ABS) e latão, pelo número de canais e pelas dimensões. O fluido de trabalho utilizado foi R134a. A literatura indica micro tubos de calor como soluções proeminentes e de destaque para resfriamento de micro sistemas. Estes dispositivos podem ser adaptados a diferentes condições térmicas através da mudança de fluidos de trabalho, geometrias e materiais base do trocador. O estudo teórico foi baseado no modelo de circuitos térmicos proposto no presente trabalho, que visa calcular indicadores de desempenho térmico, sendo condutividade térmica efetiva e resistência térmica equivalente dos micro tubos de calor a partir das temperaturas obtidas experimentalmente. O estudo experimental foi baseado em obter distribuições de temperaturas dos dispositivos propostos sob diferentes condições de trabalho, variando-se a fração de enchimento de fluido de trabalho, inclinação e temperatura do condensador. Os resultados obtidos para o arranjo de micro tubos de calor em latão demonstrou uma razão de aumento de até 1482% na capacidade de transporte de calor, enquanto que o arranjo de micro tubos de calor em ABS apresentou uma razão de aumento de 247%. Os melhores desempenhos de ambos os casos foram observados para ângulos positivos com baixas frações de enchimento. / The purpose of this work is the theoretical and experimental study on the thermal performance of two micro heat pipes arrays. The differences between the arrays are the base substrate, which are Acrylonitrile Butadiene Styrene (ABS) and brass, the number of channels and their dimensions. The working fluid used was R134a. Previous works indicate micro heat pipes as prominent solutions for the cooling of micro systems. These devices can be adapted to different thermal conditions by changing the working fluids, geometries and base materials of the heat exchanger. The theoretical study was based on the thermal circuits model presented in this work, that aims on computing thermal performance indicators, such as the effective thermal conductivities and the equivalent thermal resistances of the micro heat pipes from the temperatures obtained experimentally. The experimental study was based on obtaining temperature distributions of the micro heat pipes under different working conditions, by varying the working fluid filling ratio, tilt angle and the temperature of the cooling water at the condenser. The results obtained for the brass micro heat pipe array showed a performance ratio increase up to 1482% in heat transfer capacity, while the ABS micro heat pipe array showed a performance ratio increase of 247%. The best performance for both cases were observed for positive tilt angles with low working fluid filling ratios.
6

Computation and Simulation of the Effect of Microstructures on Material Properties

Carter, W. Craig 01 1900 (has links)
Many material properties depend on specific details of microstructure and both optimal material performance and material reliability often correlate directly to microstructure. In nano- and micro-systems, the material's microstructure has a characteristic length scale that approaches that of the device in which it is used. Fundamental understanding and prediction of material behavior in nano- and micro-systems depend critically on methods for computing the effect of microstructure. Methods for including the physics and spatial attributes of microstructures are presented for a number of materials applications in devices. The research in our group includes applications of computation of macroscopic response of material microstructures, the development of methods for calculating microstructural evolution, and the morphological stability of structures. In this review, research highlights are presented for particular methods for computing the response in: 1) rechargeable lithium ion battery microstructures, 2) photonic composites with anisotropic particulate morphologies, 3) crack deflection in partially devitrified metallic glasses. / Singapore-MIT Alliance (SMA)
7

[en] A SERIES INTERCONNECTING SYSTEM FOR INTELLIGENT STATIONS / [pt] SISTEMA PARA INTERLIGAÇÃO SÉRIE ENTRE ESTAÇÕES INTELIGENTES

EDMARSON BARCELAR MOTA 21 December 2006 (has links)
[pt] A interligação de mini ou micro-sistemas, seja através de processamento distribuído ou rede, torna-se nos dias atuais muito vantajosa em termos desempenho/custo, quando comparado a sistemas centralizados e via de regra com computadores de grande porte. Este trabalho apresenta um sistema de interligação série orientado para microcomputadores, com controle de barra de comunicação descentralizado. Apresenta como atrativos o baixo custo do hardware necessário à colocação de uma nova estação na rede, o protocolo simples e versátil, modular, e com a possibilidade de colocação de um número ilimitado de estações inteligentes. O seu desempenho pode ser considerado adequado quando utilizado em um ambiente onde não haja excessiva assiduidade à rede; laboratórios universitários e de pesquisa, assim como diversos tipos de controle industrial são bons exemplos. / [en] Mini or micro-systems interconnection, implemented through distributed processing or network, is nowadays more attractive viewed Performance / Cost than main frame centralized huge computers. This work shows a serial network system mainly for usage with microcomputer stations, with descentralized bus control. Main characteristics are low hardware cost to append a new station to the bus, simple protocol, modular design, and ability to support an unlimited number of systems on line. Its performance can be considered adequate when used in environments free from excess of requests to the network bus. University research laboratories, besides several kinds of industrial control applications, may be considered good examples.
8

Förbättring av sjukskrivningsprocess med Sex Sigma och mikrosystem perspektiv

Berg, Jenny, Widell, Yvonne January 2012 (has links)
Bakgrund: Sjukfrånvaron i Sverige 2004 var högst i Västeuropa och landets enskilt största ekonomiska problem. Regeringen vidtog åtgärder för att minska sjukfrånvaron. En del var att ge incitament för att sjukskrivningsprocessen skulle finnas med i hälso- och sjukvårdens ledningssystem, delvis på grund av förändrade krav och därmed brister i läkarintygens kvalitet. En lokal undersökning vid ortopedkliniken Kärnsjukhuset visade att 23 % av patienterna var missnöjda i samband med sjukskrivning. Syfte: Genom Sex Sigmas problemlösningsmodell DMAIC i kombination med mikrosystemperspektivet förbättra kvaliteten på läkarintygen, skapa mål och rutiner i sjukskrivningsprocessen samt öka patientnöjdhet  Metod: Utifrån ett mikrosystemperspektiv intervjuades projektgruppsdeltagare. Genom Sex Sigmas problemlösningsmodell fokuserades förbättringsområden på informationsutbyte till patienter och läkare samt utformande av mål och skriftliga rutiner. Femtioåtta patienter intervjuades om hur nöjda de var med sin sjukskrivning. Mätningar av ”onödiga” åtgärder utfördes och kvaliteten i läkarintygen följdes med styrdiagram. Förbättringsprojektet utvärderades kontinuerligt genom reflektion i projektgruppen. Resultat: Förbättringsarbete med hjälp av Sex Sigma och mikrosystemperspektiv har bidragit signifikant till ökad kvalitet i läkarintygen, p<0,001. Rutiner och mål för sjukskrivningsprocessen har implementerats i ledningssystemet. Hundra procent av patienterna på ortopedkliniken är nöjda och telefonsamtal om brister och felaktiga ärenden har minskat. Förbättringsmetodiken har bidragit till ett vidgat synsätt, ökad förståelse för patienten och mellan personalkategorier. Åtgärderna har haft genomslagskraft genom att förbättringsförslagen kom från dem som arbetar i verksamheten och genomfördes med egen personal. Diskussion: Sex Sigma och mikrosystemperspektivet har patientfokus vilket kan påverka värderingar och vilja till förändringar. Resultatet från denna studie stöder det som kommit fram i andra studier och arbetssättet gav signifikant förbättrat resultat. Förbättringsåtgärderna är inte generaliserbara men arbetssättet kan med fördel tillämpas i förbättringsarbete. Ytterligare studier av arbetssättet och dess hållbarhet över tid behövs för att stärka evidensen. / Background: The sickness absence in Sweden 2004 was highest inWestern Europe and the country's main economic problem. The government gave incentives to make the sick-leave process included in healthcare management system, partly because of changing requirements and deficiencies in the quality of medical-certificates quality. A local study at an orthopedic clinic showed that 23% of patients were dissatisfied with sick-leave. Purpose: Through Six Sigma's DMAIC problem-solving model in combination with micro-systems perspective, improving the quality of medical certificates, create goals and routines in the sick-leave process and increase patient satisfaction Method: Interviews of project participants were carried out using a micro-systems perspective. Through Six Sigma problem-solving model areas of improvement were focused on information exchange to patients and physicians as well as formulating goals and written routines. Fifty-eight patients were interviewed about their sick-leave satisfaction. Measurements of "unnecessary" actions were performed and the quality of medical certificates was followed with control-charts. The improvement project was evaluated by reflection in the group continuously. Results: Improvements with Six Sigma and micro-systems perspective has contributed to improving the quality of medical certificates significantly p<0.001. Routines and goals for sick-leave process have been implemented in the management system. 100% of the patients at the orthopedic clinic are satisfied. Phone calls about deficiencies and incorrect cases have decreased. This methodology has contributed to a broadened understanding of patients´ experiences and between different staff-categories. The actions have had impact because the improving proposals came from and were carried out by its own staff. Discussion: The Six Sigma and the micro-systems perspective has patient focus which can affect the values and willingness to change. The result from this study supports other studies and the approach in this study resulted in significantly improved results. Improvement actions are not generalizable, but the approach can be usefully applied in improvement efforts. Further studies of the approach and its sustainability over time are needed to strengthen the evidence.
9

Forms and Functioning of Local Accountability Mechanisms for Maternal, Newborn and Child Health: A Case Study of Gert Sibande District, South Africa

Mukinda, Fidele Kanyimbu January 2021 (has links)
Philosophiae Doctor - PhD / The value of accountability as a key feature of strengthening health systems and reducing maternal, newborn and child mortality is increasingly emphasised globally, nationally and locally. Frontline health professionals and managers play a crucial role in promoting maternal, newborn and child health (MNCH) services in an equitable and accountable manner. They are at the interface between higher-level health system management and communities, facing demands from both sides and often expected to perform beyond their available means. Although accountability is a central topic in the governance of MNCH literature, it has mostly been approached at global and national levels, with little understanding of how accountability is integrated into the routine functioning of local health systems. This PhD explores the forms and functioning of accountability at the district level focusing on MNCH as a programmatic area with long-established institutional mechanisms (structures and processes) in South Africa (SA). The thesis is presented in the form of four empirical papers (published or submitted), exploring different dimensions of accountability, which are embedded in a series of narrative chapters. In this thesis, accountability is understood as a set of relations between an accountholder and ‘accountor’ (or duty bearer), in which the latter provides information or justification for actions or decisions taken, and faces the resulting consequences of his/her actions (reward or sanction). Accountability mechanisms are the means to regulate accountability relationships and include broad strategies, interventions or instruments. These mechanisms can take various forms including performance, financial and public accountability, and operate both vertically (accountability inside bureaucratic hierarchies, or towards external stakeholders and/or the community), or horizontally (between peers, ‘neighbour’ units, departments or ministries in a national health system). Drawing conceptually on the field of governance and considering the complexity of the accountability phenomenon, I adopted a case study approach to the PhD research, using a combination of policy document review, interviews (with managers, providers, community representatives and members of labour unions) and field observations, conducted iteratively over 16 months. The study was conducted in Gert Sibande District, one of the three South African health districts in Mpumalanga Province, with an in-depth focus on two of the seven sub-districts in the District. The research found that frontline health professionals have a clear understanding and conceptualisation of accountability in the SA health policy context, despite the reported inability to define accountability by health professionals described in the literature. Respondents referred to accountability as responsibility, answerability and virtue, and also argued for strengthening accountability mechanisms as critical to addressing maternal and child mortality. While deeming accountability as important, frontline professionals experienced the existing accountability mechanisms as ‘too much’ and indicated the desire for the streamlining of existing mechanisms. In this regard, the study documented numerous mechanisms at district level, almost all related to performance accountability in MNCH. These included a performance management system, quality assessment and accreditation processes, quarterly reviews, and death surveillance and response processes. The existence of multiple and overlapping accountability mechanisms engenders operational confusion and ‘accountability overload’ for frontline providers, encouraging empty bureaucratic compliance, while critical gaps – notably in community accountability – remain. In practice, at their best, some mechanisms operate following a reciprocal1 pathway of capacity building with resource provision (from management) and expectation for better performance (from providers). There were, however, contextual variations in the implementation and practice of the mechanisms between sub-district settings. The fieldwork observations and interviews were also able to document how formal institutionalised mechanisms are embedded within a complex system of informal accountability relationships and social norms (‘accountability ecosystem’) that enables or constrains the ability of frontline professionals to fulfil their tasks. In addition, using a Social Network Analysis approach, the research identified key actors and their involved network, which form the relational backdrop to the functioning of accountability mechanisms for MNCH. By revealing complex relationships and collaboration patterns among frontline health professionals, the study was able to show the multi-level action and multiple actors required to achieve MNCH goals.
10

Entwicklung eines miniaturisierten Ionenfilters und Detektors für die potentielle Anwendung in Ionenmobilitätsspektrometern

Graf, Alexander 22 May 2015 (has links) (PDF)
Die Ionenmobilitätsspektrometrie ermöglicht eine selektive Detektion von niedrigkonzentrierten Gasen in Luft. Darauf beruhende Analysegeräte können verhältnismäßig einfach umgesetzt werden und in vielfältigen mobilen Einsatzszenarien wie der Umweltanalytik Anwendung finden. Die vorliegende Dissertation gibt einen Überblick über die Grundlagen der Ionenmobilitätsspektrometrie und setzt die funktionellen Teilkomponenten Ionenfilter und Ionendetektor mit Mikrosystemtechniken um. Dafür werden Möglichkeiten aus dem Stand der Technik vorgestellt und eine für die Umsetzung optimale Variante identifiziert. Ein Ionenfilter basierend auf der Differenzionenmobilitätsspektrometrie zeigt diesbezüglich ein sehr geeignetes Skalierungsverhalten. Zur Integration in einen Demonstrator-Chip wird ein neuartiges Bauelementkonzept verfolgt, mit technologischen Vorversuchen untersetzt und erfolgreich in einen Gesamtherstellungsablauf überführt. Mit Hilfe von weiterführenden analytischen Untersuchungen werden spezifische Phänomene bei der elektrischen Kontaktierung der verwendeten BSOI-Wafer als Ausgangsmaterial hergeleitet und Empfehlungen zur Vermeidung gegeben. Der Funktionsnachweis der Teilkomponente Ionendetektor wird anhand von hergestellten Demonstrator-Chips und mit Hilfe eines entwickelten Versuchsaufbaus begonnen. Es werden die weiteren Schritte zum Nachweis der Gesamtfunktionalität abgeleitet und festgehalten. Auf Basis des umgesetzten Bauelement- und Technologiekonzepts und der vorliegenden Ergebnisse, wird das entwickelte und realisierte Gesamtkonzept als sehr aussichtsreich hinsichtlich der favorisierten Verwendung als Teilkomponente eines miniaturisierten Ionenmobilitätsspektrometers eingeschätzt.

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