Dissertations / Theses: 'Tunnel technology'

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Persson, Tobias. "Wind Tunnel Effects on Truck Aerodynamica and Soiling." Thesis, KTH, Mekanik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-203972.

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Erlandsson, Olof. "Comparison of Tunnel Convergence Measurement Methods." Thesis, KTH, Fastigheter och byggande, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-276439.

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When creating cavities below ground, movements occur in the surrounding soil due to disrupted equilibrium. In tunnel constructions these displacements are referred to as tunnel convergence. This report compares four dierent methods for monitoring tunnel convergence with regards to both measurement precision and method cost. Three of the methods are based on displacement measurements of optical targets placed at regular intervals in the tunnel. Presented is also a method using a combination of wireless tilt and distance sensors to monitor tunnel convergence. The overall conclusion is that measurement precision and cost are well correlated. However, important to consider is that tunnel convergence monitoring cost is faceted and not only the obvious cost of equipment and labour, but also the indirect cost from interfering with other activities in the tunnel. Measurement precision of the dierent methods was determined by applying the methods in a lab environment, congured to eliminate any possible movements, and analysing the distribution of the displacement demonstrated by each method. In addition, information regarding the labour eort required to prepare and perform the measurements was also collected. Based on the experiments and literature studies, the report discusses the criteria to consider when selecting a tunnel convergence monitoring method and presents a comparison of the four methods included in the study.
Vid skapandet av underjordiska hålrum uppträder rörelser i den omgivande marken på grund av att jämvikten upphävs. I tunnelkonstruktioner kallas dessa förskjutningar för tunnelkonvergens. Denna rapport jämför, med avseende både på precision och kostnad, fyra metoder för mätning av tunnelkonvergens. Tre av metoderna baseras på förskjutningsmätningar av optiska mål placerade på regelbundna avstånd längs tunneln. Rapporten presenterar även en metod där en kombination av trådlösa tilt- och distanssensorer används för att monitorera tunnelkonvergens. Den övergripande slutsatsen är att mätprecision och kostnad är väl korrelerade. Viktigt är dock att beakta de olika delarna i den totala kostnaden, som inte bara består av kostnader för arbetskraft och utrustning utan även indirekta kostnader på grund av att annan verksamhet hindras under mätaktiviteter. Mätprecisionen för de olika metoderna uppskattades genom att analysera fördelningen av mätvärden uppmätta i en lab-miljö beskaffad så att inga rörelser förväntades. Från labmätningarna noterades även omfattningen av den arbetsinsats som krävs för att förbereda och utföra mätningarna. Med mätningarna och litteraturstudier som bakgrund diskuteras kriterier att beakta när man väler metod för konvergensmätning. Baserat på dessa kriterier jämförs de fyra metoderna.

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Inghels, Pieter. "Wind tunnel blockage corrections forwind turbine measurements." Thesis, KTH, Mekanik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-202632.

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Wind-tunnel measurements are an important step during the windturbinedesign process. The goal of wind-tunnel tests is to estimate theoperational performance of the wind turbine, for example by measuringthe power and thrust coecients. Depending on the sizes of both thewind turbine and the test section, the eect of blockage can be substantial.Correction schemes for the power and thrust coecients havebeen proposed in the literature, but for high blockage and highly loadedrotors these correction schemes become less accurate.A new method is proposed here to calculate the eect a cylindricalwind-tunnel test section has on the performance of the wind turbine.The wind turbine is modeled with a simplied vortex model. Usingvortices of constant circulation to model the wake vortices, the performancecharacteristics are estimated. The test section is modeled witha panel method, adapted for this specic situation. It uses irrotationalaxisymmetric source panels to enforce the solid-wall boundary condition.Combining both models in an iterative scheme allows for thesimulation of the eect of the presence of the test-section walls on windturbines performace.Based on the proposed wind-tunnel model, a more general empirical correlationscheme is proposed to estimate the performance characteristicsof a wind turbine operating under unconned conditions by correctingthe performance measured in the conned wind-tunnel conguration.The proposed correction scheme performs better than the existing correctionschemes, including cases with high blockage and highly loadedrotors.

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Lyu, Zhipeng. "Aerodynamic Wind Tunnel in Passenger Car Application." Thesis, KTH, Mekanik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-203971.

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The thesis aims to provide an evaluation on the Volvo 1/5th scaled wind tunnel regarding its potentials and capabilities in aerodynamic study. The flow quality in the test section was evaluated. The experiments were performed included measurements of airspeed stability, tunnel-wall boundary layer profile and horizontal buoyancy. A numerical model was developed to predict the boundary layer thickness on the test floor. Repeatability tests were also conducted to establish the appropriate operating regime.A correlation study between the 1/5th scaled wind tunnel (MWT) and full scale wind tunnel (PVT) was performed using steady force and unsteady pressure measurements. The Volvo Aero 2020 concept car was selected to be the test model.The Reynolds effect and the tunnel-wall boundary layer interference were identified in the steady force measurements. Unsteady near-wake phenomena such as wake pumping and wake flapping were discussed in the unsteady base pressure measurements.

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DALLA, ROSA LEONARDO. "Structural Health of a concrete tunnel lining under complex in situ loading." Thesis, KTH, Bro- och stålbyggnad, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-255537.

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Supporting structures were designed for a utility tunnel in hard rock which was to be intersectedby some road tunnels. With the intersections involving partial overlapping between the idealcross-sections, a concrete lining and post-tensioned steel cables were added to support theutility tunnel prior to the excavation of the road tunnels. The objectives in this work wereto identify the structural behaviour of the system, assess the present state of the supportingstructures and suggest an effective monitoring strategy. Preliminary information was collectedfrom the original drawings, technical specifications as well as from site visits. Using on thefinite elements software Comsol Multiphysics, suitable models were built to represent thetunnel intersections and to test hypotheses. The significant uncertainties in the problem wereaddressed by studying limit cases and discussing their results. A measure of validation wasgained from comparing cracks in concrete on site with cracking hotspots predicted by themodel. It was concluded that the behaviour of the lining is not compatible with that of cablesuspended structures and that concrete is subject to relatively high state of stress. Monitoringcable forces was found to be an ineffective strategy for identifying changes in the structuralsystem. Monitoring the evolution of cracks in concrete was found to be the most feasiblestrategy.

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Domingo, Sabugo María. "Systematic errors in the characterization of rock mass quality for tunnels : a comparative analysis between core and tunnel mapping." Thesis, KTH, Jord- och bergmekanik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-233126.

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This thesis analyzes the potential systematic errorin the characterization of the rock mass quality in borehole and tunnel mapping. The difference when assessing the rock mass quality refers to the fact that the characterization performed on drilled rock cores are commonly done on-meter length, while the tunnel section can be up to 20-25 m wide. At the same time, previous studies indicate that the engineering geologist tends to characterize the rock mass quality during tunnel excavation with a conservative estimation of the parameters defining the rock mass quality to ensure a sufficient rock support. In order to estimate this possible systematic error produced by the size difference when assessing the rock mass quality, a simulation was performed within a geological domain, representative of Stockholm city. In the simulation, each meter of the tunnel section was given a separate value of the rock mass quality, randomly chosen from a normal distribution representative for the studied geological domain. The minimum value was set to represent the characterized rock mass quality for that tunnel section. The results from the simulation produced a systematic error due to the difference between the geological domain, reproducing the borehole mapping, and the simulated values, representing the tunnel mapping. The results showed a systematic error in the RMR basic index around 15 points in average, which compared to the difference of 5-7 points obtained in Norrström and the Norrmalm tunnels in the Stockholm Citylink project recently constructed, are found to be excessive. However, in the simulation, it was assumed that (1) the results obtained were the same in the bore hole mapping and in the tunnel mapping, (2) with the only difference of the engineer geologist assigning to the tunnel section the lowest RMR basic value, and (3) that there was no spatial correlation between the quality RMR basic index. After analyzing the three assumptions the simulation was based upon, the absence of spatial correlation was found to be the most significative, which indicate that spatial correlation in rock mass quality needs to be included if a more correct value should be obtained.

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Li, Guijun, and 李桂君. "Development of recording technology with FePt recording media and magnetic tunnel junction sensors with conetic alloy." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hub.hku.hk/bib/B50899776.

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With highly demanding requirement in current emerging cloud storage and personal computers, hard disk drive recording with high stability and high volume has attached much attention in industry and academy. Recording media and recording head feasible for future high-density recording are both crucial to utilize magnetic recording with 1T bit/in2 recording density. Recoding media with FePt for high density and high stability was investigated in this thesis using FePt polymers with imprinting methods and FePt thin films with ion-beam bombardment technologies. The FePt polymers can be patterned using imprint at micro-and nano-scales. The micro-and nano-patterns could be retained on substrates after sintering at high temperatures. The high magnetic coercivity was proved with line and dot patterns at different scales. Recording heads with Al2O3based magnetic tunneling junction sensors were also studied in thesis. The magnetic tunneling junction sensors were proved to work stable at different temperatures varying from -30oC to 100oC. The long time running test up to 100 hours also proved the stability of the magnetic tunneling junction sensors working in extreme temperatures. Withstate-of-art patterning and depositing technologies, new ideas about using FePt polymer to work as magnetic recording media and using ion beam bombardments to tune the FePt magnetic properties were verified. The feasibility of using Al2O3 based magnetic tunneling junction sensors as recording head was also discussed.
published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy

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Taylor, Nigel John. "Adaptive wall technology for two-dimensional wind tunnel testing at high subsonic through to low supersonic speeds." Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294622.

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Sanches, José Afonso. "Understanding the dynamics of a tunnel oven : Use of infrared sensors to measure the temperature of the conveyor belt in a tunnel oven used in bread production." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-70363.

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During the continuous production of bread sometimes there are problems that lead to interruptions in the production and consequently to quality problems. One such problem is the bread burning in the contact area between the bread and the conveyor belt. In order to understand the problem and to know how to quantify it, it is necessary to understand what a thermodynamic system is and what types of systems exist, how the various types of heat transfer are processed, how to measure the temperature of an object by infrared radiation and some mathematical methods such as the least square root method. Temperature measurements were planned and carried out. The goal with the first experiment was to understand how the temperature of the conveyor belt varies during an interruption. All the other tests were done to investigate the effects of different solutions in the temperature variation of the belt. According to the results, the best solution is to turn off the oven during an interruption and the worst to spray the belt with water. To spray the belt with water may be a better solution than these results shows, but it is very affected by other problems, like depositions of limestone on the nozzles. A lot more solutions could be found but due to the time available, it was not possible to investigate all the variables/solutions in the process. A long-term study would help understand much more within the regulation of the industrial baking process.
Under kontinuerlig produktion av bröd finns det ibland problem som leder till avbrott i produktionen och kvalitetsproblem. Ett sådant problem är att brödet blir bränt i kontaktytan mellan brödet och transportbandet. För att förstå problemet och veta hur man kvantifierar detta, är det nödvändigt att förstå vad ett termodynamiskt system är och vilka typer av system finns, hur olika typer av värmeöverföring sker, hur man mäter temperatur med hjälp av infraröd strålning och några matematiska metoder som minst kvadratrotsmetoden. Temperaturmätningar planerades och genomfördes. Målet med det första experimentet var att förstå hur transportbandets temperatur varierar under ett huppehåll. Alla andra tester utförades för att undersöka effekterna av de olika lösningarna i bandets temperaturvariation. Enligt resultaten är den bästa lösningen att stänga av ugnen under ett uppehåll och det värsta att spreya bältet med vatten. Att spreya bältet med vatten kan vara en bättre lösning än vad resultaten visar, men det påverkas mycket av andra problem, som avsättningar av kalksten på munstyckena. Många fler lösningar kunde hittas men det var inte möjligt att undersöka alla variabler / lösningar i processen på grund av tillgänglig tid. En långsiktig studie skulle hjälpa till att förstå mycket mer inom regleringen av industriell bakning.

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CONTRERAS, MORENO Jorge, and KIBRET DAWIT GHEBREIGZIABHER. "Aeration and risk mitigation for flood discharge tunnel in Zipingpu water conservancy project." Thesis, KTH, Betongbyggnad, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-275668.

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The importance of hydraulic structures has become an essential mitigating mean for floodsthat occur more often due to climate change. Thus, the importance and safety of flooddischarge tunnels has promoted further studies and experiments on the topic to mitigatedamages, such as cavitation that arise because of high speed flows.After an experimental study on a physical model was carried out on the flood discharge tunnelin Zipingpu Water Conservancy project, a CFD model was designed and simulated in thecommercial software ANSYS Fluent. The simulations aimed to evaluate and examine the riskfor cavitation in the tunnel, examine the design problems of the structure and analyse theinstalled aerators for the mitigation of cavitation. Moreover, using CFD models as acomplementary form to physical models was analyzed.A three dimensional geometry of the discharge tunnel was built in ANSYS Spaceclaim and themesh conducted with ANSYS mesh generator. The known boundary condition such as thedesign flow conditions, velocity inlet, pressure inlets and pressure outlet were set. For themodel a multiphase VOF scheme with RANS approach, k-ϵ turbulence model and a standardwall function was set.The results from the initial simulations showed that the discharge tunnel was under cavitationrisk, since the recorded cavitation index in the tunnel was below 1.8. After having revised thelayout of the aerators in order to mitigate cavitation risk, the results from the simulations withadded aerators were sufficient to mitigate the risk as the cavitation index was still below 1.8.The results for the cavitation index remained unchanged even in the simulated models with adifferent solver setup that were used in the comparison with the experimental data in order tovalidate them.As a conclusion, it was recommended that the tunnel design has to be revised and improvedby adding more aerators and air vents to mitigate the cavitation risk. Furthermore, more studieson the discharge tunnel or similar tunnels with similar conditions should be carried out in orderto validate the results of this study and determine if numerical models are preferable to physicalmodels

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Abdo, Aslan. "Modeling contingency infiltration scenarios in MODFLOW : Stockholm Bypass and tunnel induced groundwater drawdown." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-244307.

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Subsurface constructions, such as tunnels, create hydrogeological challenges in mitigating risk of subsidence due to groundwater drawdown. Presenting readily made precautionary mitigation plans, such as strategically planned artificial recharge applications, can help effectivise the mitigation process. The Bypass Stockholm project comprises of several subsurface constructions which may lower the surrounding groundwater level through tunnel leakage. Risk of land subsidence persists in the nearby urban area of Vinsta, Stockholm, where a groundwater drawdown may cause the clays in the area to experience land subsidence. A hydrogeological modelling approach was used in the area to create strategic artificial infiltration plans that could be employed as a mitigative response to the drop in groundwater head. In order to simulate the potential tunnel drainage, a steady state hydrogeological model was built using MODFLOW. A 220 l/s tunnel leakage was then simulated. Four different artificial groundwater infiltration scenarios were then conceptualized and simulated to observe effects on groundwater heads. The groundwater levels of the baseline model of the area fit the calibration targets with average absolute deviation of 0.18 m. The tunnel drainage scenario lowered the groundwater level in the till aquifer and bedrock by 0 - 1.5 m and 0.5 - 5 m respectively, with higher drawdowns observed closer to the tunnel. The infiltration scenarios mitigate the groundwater drawdown with different efficacies; proximity to the recharge point, and discharge into the till aquifer were observed to have the highest effect on groundwater recharge in the model. The model could have been improved by improving the data quality surrounding the hydraulic conductivity of the bedrock, as it had the highest effect according to the parameter sensitivity analysis.
Konstruktioner under mark kan skapa hydrogeologiska utmaningar, såsom sättningsrisk orsakade av grundvattenavsänkning. Ett sätt att effektivisera åtgärdsprocessen är att förbereda för eventuell artificiell grundvatteninfiltration. Vägprojektet Förbifart Stockholm innefattar konstruktioner under mark och riskerar, genom inläckage, att sänka grundvattennivån i omgivningen. Ett potentiellt problemområde är stadsdelen Vinsta, delar av vars är byggd på sättningskänslig lera som kan påverkas av en grundvattenavsänkning. För att kunna motverka en grundvattensänkning i Vinsta har hydrogeologisk modellering utförts för att strategiskt planera artificiell grundvatteninfiltration. Ett tunnelläckage på 220 l/s har simulerats genom en hydrogeologisk steady state-modell i MODFLOW. Fyra olika scenarier för grundvatteninfiltration har konceptualiserats och simulerats för att observera påverkan på grundvattennivån. Den spatialt variabla grundvattennivån i grundmodellen nådde kalibreringsmålen med en genomsnittlig absolutavvikelse på 0,18 m. Modellen för tunnelläckage resulterade i att grundvattennivån i moränakvifären och berget sjönk med 0 – 1,5 resp. 0,5 – 5 m, med större grundvattensänkning närmare tunneln. Scenarierna för infiltration motverkade grundvattensänkningen i olika grad. Närhet tilltunneln, eller platsen för inläckage, samt den hydrauliska konduktiviteten mellan infiltrationen och akvifären visade störst påverkan på resultatet för att motverka grundvattensänkningen. Känslighetsanalysen för parametrarna i modellen visade att berget och dess hydrauliska konduktivitet hade störst påverkan på resultatet. Tillgång till bättre data för berget möjliggör förbättrat modelleringsresultat.

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Beder, Sharon Science &amp Technology Studies (STS) UNSW. "From pipe dreams to tunnel vision : engineering decision-making and Sydney's sewerage system." Awarded by:University of New South Wales. Science and Technology Studies (STS), 1989. http://handle.unsw.edu.au/1959.4/20621.

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The broad theme of this thesis is engineering decision-making. The various factors that shape technological development are investigated using the development of Sydney's sewerage system as a case study. The thesis focuses on various key decisions, past and present, including the choice of water-carriage technology for sewage collection, the selection of sewage treatment technologies, and on-going preference of engineers and bureaucrats for ocean disposal. Also covered are the legislative and regulatory mechanisms, the policies of the Sydney Water Board with regard to industrial waste disposal and the relationship between the Board and the public. A study was made of historical documents, engineering reports and papers, parliamentary debates, annual reports, minutes, newspaper reports and secondary sources and personal interviews were conducted. Various bodies of literature were referred to and used, including the books and articles on the history and sociology of engineers, the politics of expertise and public participation and the emerging discipline of science and technology studies. It is concluded that the development of Sydney's sewerage system has been shaped by social, political and economic factors and that engineers have played a pivotal role in the decisions made through their deliberate shaping of knowledge and the performance of predictions they have made for various options. The decisions made in this way have been defended against public opinion and public participation in the decision-making process has been kept to a minimum. This thesis supports the argument that technology is socially constructed, that the technical cannot be separated from the social, and that an interactive model of technological development is more appropriate than a linear, causal one. It shows that the role of power in the shaping of technology is crucial, and in particular the alliance of state and professional power that occurs in the shaping of public sector technology.

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Oliveira, Rone Batista de [UNESP]. "Caracterização funcional de adjuvantes em soluções aquosas." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/101668.

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Made available in DSpace on 2014-06-11T19:31:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-07Bitstream added on 2014-06-13T19:20:42Z : No. of bitstreams: 1 oliveira_rb_dr_botfca.pdf: 2430018 bytes, checksum: 83351333d3d9c8a67f6e396d9780730d (MD5)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
A alta demanda por agrotóxicos pelos sistemas de produção agrícola, aliada ao possível uso inadequado desses produtos, torna a deriva um dos maiores problemas potenciais da agricultura atual, e a escolha correta de adjuvantes pode ser uma das alternativas para minimizar os impactos negativos causados pela deriva nas pulverizações. Este trabalho foi desenvolvido com o objetivo de avaliar o efeito proporcionado por diferentes grupos de adjuvantes nas propriedades físicas e químicas das soluções, no espectro de gotas, bem como no potencial do risco de deriva quantificado em túnel de vento, como forma de auxiliar na escolha correta desses produtos para melhor utilização nas aplicações de agrotóxicos. Foram selecionados 18 adjuvantes comumente utilizados em misturas com agrotóxicos em pulverizações agrícolas, avaliando-se as propriedades físicas e químicas dos mesmos em soluções aquosas (viscosidade, densidade, tensão superficial e condutividade elétrica), o espectro de gotas e o potencial de deriva medido em túnel de vento. O experimento foi composto de 33 tratamentos, tendo a água como testemunha adicional, resultantes da diluição dos adjuvantes em diferentes concentrações, com três repetições. Para os ensaios em túnel de vento e análise de espectro de gotas foi utilizada uma ponta de pulverização XR8003 VK na pressão de 200 kPa, gerando um padrão de gotas médias. A deriva foi coletada no túnel de vento com fluxo de ar na velocidade de 2 m s-1. O corante Azul Brilhante a 0,6% (m v-1) foi utilizado como marcador para todas as soluções pulverizadas visando a quantificação da deriva por espectrofotometria. Os resultados mostraram que a adição de adjuvantes alterou as propriedades físicas e químicas das soluções aquosas em diferentes magnitudes, dependendo da concentração utilizada. Os surfatantes organosilicones...
Due to the high demand for pesticide by the agricultural systems and the possible inadequate use of the products, drift became one of the biggest concerns of the modern agriculture, and the correct use of adjuvants may be one of the possible alternatives to minimize the negative impact of spray operations. This study was developed to evaluate the effect of different adjuvants on physical and chemical properties of spray solutions, droplets spectra as well as drift potential measured in wind tunnel, aiming the correct choice of adjuvants to improve efficiency in pesticide application. For this purpose 18 commercially available agricultural spray adjuvants were selected including products usually mixed up with pesticides in the sprayer tank. The evaluation included physical and chemical properties of spray solutions (viscosity, density, surface tension and electric conductivity), droplets spectra and drift risk potential measured in wind tunnel. The experiment was set up with 33 treatments (solutions) obtained from 18 adjuvants used in different concentrations with 3 replications, including pure water as a standard. For wind tunnel tests and droplet spectra analysis it was used a Teejet XR8003 flat fan nozzles at 200 kPa (medium droplets) and all solutions were mixed up with a food color dye (Blue FDC) at 0,6% m v-1 for spectrophotometry analysis of drift deposits on the wind tunnel. The results showed that the addition of adjuvants changed physical and chemical properties of spray solutions in different magnitudes according to the product concentration. The organosilicon surfactants (Silwet 0.1% e 0.2% and BreakThru 0,1%) had the lowest values for surface tension, while the drift retardant based polymers (Define 0,06% e 0,12%) had the highest values for viscosity and density. There was high correlation between the Volume Median Diameter (VMD) and percentage of droplets smaller... (Completo abstract click electronic access below)

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Guttman, Jeremy. "Polymer-based Tunnel Diodes Fabricated using Ultra-thin, ALD Deposited, Interfacial Films." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469125487.

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Oliveira, Rone Batista de 1977. "Caracterização funcional de adjuvantes em soluções aquosas /." Botucatu : [s.n.], 2011. http://hdl.handle.net/11449/101668.

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Orientador: Ulisses Rocha Antuniassi
Banca: Otavio Jorge Gricoli Abi Saab
Banca: Marco Antonio Gandolfo
Banca: Carlos Gilberto Raetano
Banca: Paulo Roberto Arbex Silva
Resumo: A alta demanda por agrotóxicos pelos sistemas de produção agrícola, aliada ao possível uso inadequado desses produtos, torna a deriva um dos maiores problemas potenciais da agricultura atual, e a escolha correta de adjuvantes pode ser uma das alternativas para minimizar os impactos negativos causados pela deriva nas pulverizações. Este trabalho foi desenvolvido com o objetivo de avaliar o efeito proporcionado por diferentes grupos de adjuvantes nas propriedades físicas e químicas das soluções, no espectro de gotas, bem como no potencial do risco de deriva quantificado em túnel de vento, como forma de auxiliar na escolha correta desses produtos para melhor utilização nas aplicações de agrotóxicos. Foram selecionados 18 adjuvantes comumente utilizados em misturas com agrotóxicos em pulverizações agrícolas, avaliando-se as propriedades físicas e químicas dos mesmos em soluções aquosas (viscosidade, densidade, tensão superficial e condutividade elétrica), o espectro de gotas e o potencial de deriva medido em túnel de vento. O experimento foi composto de 33 tratamentos, tendo a água como testemunha adicional, resultantes da diluição dos adjuvantes em diferentes concentrações, com três repetições. Para os ensaios em túnel de vento e análise de espectro de gotas foi utilizada uma ponta de pulverização XR8003 VK na pressão de 200 kPa, gerando um padrão de gotas médias. A deriva foi coletada no túnel de vento com fluxo de ar na velocidade de 2 m s-1. O corante Azul Brilhante a 0,6% (m v-1) foi utilizado como marcador para todas as soluções pulverizadas visando a quantificação da deriva por espectrofotometria. Os resultados mostraram que a adição de adjuvantes alterou as propriedades físicas e químicas das soluções aquosas em diferentes magnitudes, dependendo da concentração utilizada. Os surfatantes organosilicones... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Due to the high demand for pesticide by the agricultural systems and the possible inadequate use of the products, drift became one of the biggest concerns of the modern agriculture, and the correct use of adjuvants may be one of the possible alternatives to minimize the negative impact of spray operations. This study was developed to evaluate the effect of different adjuvants on physical and chemical properties of spray solutions, droplets spectra as well as drift potential measured in wind tunnel, aiming the correct choice of adjuvants to improve efficiency in pesticide application. For this purpose 18 commercially available agricultural spray adjuvants were selected including products usually mixed up with pesticides in the sprayer tank. The evaluation included physical and chemical properties of spray solutions (viscosity, density, surface tension and electric conductivity), droplets spectra and drift risk potential measured in wind tunnel. The experiment was set up with 33 treatments (solutions) obtained from 18 adjuvants used in different concentrations with 3 replications, including pure water as a standard. For wind tunnel tests and droplet spectra analysis it was used a Teejet XR8003 flat fan nozzles at 200 kPa (medium droplets) and all solutions were mixed up with a food color dye (Blue FDC) at 0,6% m v-1 for spectrophotometry analysis of drift deposits on the wind tunnel. The results showed that the addition of adjuvants changed physical and chemical properties of spray solutions in different magnitudes according to the product concentration. The organosilicon surfactants (Silwet 0.1% e 0.2% and BreakThru 0,1%) had the lowest values for surface tension, while the drift retardant based polymers (Define 0,06% e 0,12%) had the highest values for viscosity and density. There was high correlation between the Volume Median Diameter (VMD) and percentage of droplets smaller... (Completo abstract click electronic access below)
Doutor

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Lovén, Sara. "Ersättning för järnvägstunnlar : En jämförelse mellan servitut och 3D - fastighet." Thesis, KTH, Fastigheter och byggande, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-211438.

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Det har skett en betydande folkökning i Stockholm under de senaste åren. För att kunna hantera ökningen ska tunnelbanan byggas ut. Stockholmsförhandlingen resulterade i planering och finansiering av ett antal nya sträckningar. Sträckningarna kommer mestadels att gå underjord och kräver markåtkomst och tillträde. För att tvångsvis få markåtkomst till järnvägstunnlar finns det två konkurrerande möjligheter antigen används tredimensionell fastighetsbildning eller servitutsrätt. När mark exproprieras eller på annat sätt tvångsvis överlåts ska ersättning utgå. Intrångsersättningen ska motsvara marknadsvärdeminskningen som intrånget gör. Syftet med studien är att jämföra överlåtelseformerna servitut och tredimensionell fastighetsbildning vid tvångsvis markåtkomst för järnvägstunnlar samt även bestämma lämplig ersättning för överlåten mark eller rättighet. En kvalitativ studie har används för att svara på syftet och frågeställningen. Metoden har inkluderat en undersökning av rättssituationen, fallstudier och intervjuer. Järnvägstunnlar i Stockholm, Göteborg och Malmö har studerats som lämpliga fall. I intervjuerna tillfrågades representanter från Stockholms Statliga och Kommunala lantmäteri, Trafikverket samt även en fastighetsvärderare. Frågorna som behandlades var om tunnelns intrång, lämplig ersättning och skillnaderna mellan servitut och tredimensionell fastighetsbildning. Undersökningen resulterade i att det är juridiskt möjligt att bilda både en tredimensionell fastighet och servitut men utifrån fallstudierna och intervjuerna har tredimensionell fastighetsbildning fördelar framför servitutsbildning. Eftersom järnvägsägaren blir fastighetsägare över tunneln så blir ansvarsfördeliningen tydligare vilket förenklar den framtida förvaltningen. När det gäller ersättningen bör den bestämmas utifrån den faktiska marknadsvärdeminskningen om det går men för de fastigheter där det är svårt att påvisa en värdeminskning kan schablonbelopp användas. Undersökningen kom fram till att intrånget blir lite större när tredimensionell fastighetsbildning används och bör resultera i lite högre ersättning.
The population of Stockholm has increased over the last few years and will continue to increase in the near future. In order to facilitate a continuing development of Stockholm the Metro will expand. The Metro expansion will run mostly underground and requires access to underground space. There are two different options to receive access either through three-dimensional property or easements. Depending on which method is used there are different consequences for the railway owner and the property owners. The purpose of this thesis is to describe the reasons for using either ownership or easements and the consequences of the choice, the effect an underground tunnel has on the property value, and if there is a difference in the effect on property value depending on which method is utilized. A qualitative study has been employed to answer the research questions. The research consisted of case studies and the interviews. Three cases have been studied; the cases are railway tunnels in Stockholm, Gothenburg and Malmö. Interviews have been held with the cadastral authorities in Stockholm, the Transportation administration, and a property evaluator specializing in infrastructure. The research concludes ownership is a more suitable for railways and makes the maintaining easier. However it can be considered more intrusive and thus the compensation received should be a little higher. The compensation values that Norell came up with are appropriate for the seized space.

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17

Moses, Kenneth C. "A Durable Terrestrial Drive Train for a Small Air Vehicle." Cleveland, Ohio : Case Western Reserve University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1270233578.

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Thesis (Master of Sciences (Engineering))--Case Western Reserve University, 2010
Department of EMC - Mechanical Engineering Title from PDF (viewed on 2010-05-25) Includes abstract Includes bibliographical references and appendices Available online via the OhioLINK ETD Center

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18

Niel, Stéphan. "Optimisation du système émetteur-base de transistors bipolaires haute performance en technologie 0,35 [mu]m, simple-polysiliciium, quasi-auto-alignée." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10186.

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Le travail presente dans ce manuscrit s'insere dans le cadre des recherches menees sur les composants bipolaires npn sur silicium au sein du centre national d'etudes des telecommunications de grenoble (cnet grenoble). Afin de realiser des transistors tres performants, nous avons tout d'abord travailles sur une des parties critiques des transistors a emetteur polysilicium : l'interface polysilicium/monosilicium. Nous presentons donc dans un premier temps, une etude originale sur la realisation de ces interfaces en utilisant une ozonation soit en ambiance gazeuse soit en ambiance aqueuse qui creent chacune une couche d'oxyde differente. Dans un deuxieme temps, nous presentons un modele de transport des porteurs a travers la barriere interfaciale qui nous permet d'extraire la resistance specifique d'interface et le coefficient de transmission des trous. Cette etude nous permet egalement de correler le bruit basse frequence a l'interface polysilicium/monosilicium et de montrer qu'il est le plus faible pour une interface la plus propre possible. Enfin, nous montrons qu'il est possible d'obtenir de tres bonnes performances dynamiques et un tres faible bruit basse frequence en utilisant une technologie simple polysilicium, quasi-auto-alignee 0,35 m avec un emetteur recristallise.

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El, zain Nadia. "An experimental study of the validity of the round panel test method for shotcrete." Thesis, KTH, Betongbyggnad, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-230981.

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Shotcrete (sprayed concrete) was used for the first time in 1914 and has become of growing importance in stabilizing the excavated tunnel sections over the past century. Even though the technology develops, there are some difficult tasks such as the design of a bolt anchored tunnel lining made of shotcrete. A proven and established design method does not exist today; instead the design of tunnel linings are based on trial and error or experience from similar projects. One method used today, to determine the actual structural behavior of fiber reinforced shotcrete, is the standard beam test method. Previous studies have shown that the beam method gives scattered results since the testing volume are relatively small and the fibers might be unevenly distributed. In 1998, an alternative to determine the actual structural behavior of reinforced shotcrete was proposed, based on using round determinate panels. In 2004 this method became a part of the American Society for Testing and Materials, ASTM, standards. The method has the potential of becoming a major, reliable test procedure that better reproduce the behavior of reinforced shotcrete in situ, compared to test beams. An experimental test series was performed to compare the different testing methods in terms of data variability and validity, in the laboratory of Vattenfall in Älvkarleby. The experiment was performed on 30 specimens in total, with five different concrete recipes. The difference in the recipe was the fiber and cement content. The round panels are designed according to ASTM C-1550 and the beams according to SS-EN14488-3. The results from the experiment is here presented and evaluated, and also including the data variability and validity for the proposed method. The two basic testing methods of using beams and round panels are investigated, compared and evaluated, and their advantages and disadvantages discussed.
Sprutbetong användes första gången år 1914 och har under det gångna århundradet blivit allt viktigare för att stabilisera utsprängda tunnelsektioner. Trots att tekniken utvecklas finns det svårigheter med att exempelvis utforma bultförankrade tunnelbeklädnader av sprutbetong. En beprövad och etablerad metod att konstruera sprutbetongbeklädnad existerar inte idag. Istället används erfarenhetsåterföring från tidigare projekt och/eller experimentella försök. En testmetod som används idag för att återskapa beteendet hos sprutbetong är balkförsök. Tidigare studier har däremot visat att resultaten från försöken oftast har stor spridning vilket kan bero på att brottytorna är små areor där fibrerna kan vara ojämnt fördelade vilket påverkar resultaten. År 1998 föreslogs en alternativ metod för att fastställa de mekaniska egenskaperna hos sprutbetong, baserat på användning av runda plattor. År 2004 blev denna metod en del av the American Society for Testing and Materials, ASTM, standarder. Metoden har potential att bli en viktigt och tillförlitligt testmetod som mer realistiskt efterliknar beteendet hos fiberarmerad sprutbetong jämfört med balkprovning. En experimentell försöksserie har genomförts hos Vattenfall i Älvkarleby, för att jämföra de två metoderna med avseende på mätosäkerhet. Försöksserien är på totalt 30 prover, där fem olika betongrecept använts. Cementmängden och fiberhalten varierade mellan de olika recepten. De runda plattorna är utförda enligt ASTM C-1550 och balkarna enligt SS-EN14488-3. Resultaten från försöken har redovisats och utvärderats, och en mätosäkerhersanalys presenteras för metoden ASTM C-1550. Korrelationen mellan resultaten från de två metoderna är beräknad och varianskoefficienten presenteras. För- och nackdelar mellan båda testmetoderna diskuteras.

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Trompille, Virginie. "Etude expérimentale et théorique du comportement d'un tunnel renforcé par boulonnage frontal." Lyon, INSA, 2003. http://theses.insa-lyon.fr/publication/2003ISAL0044/these.pdf.

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Le renforcement des tunnels par boulonnage au front de taille permet le creusement dans des terrains de mauvaise tenue. Bien que cette technique soit de plus en plus employée, l'effet réel des boulons sur l'augmentation de stabilité et la réduction des mouvements à l'avant du front reste encore difficile à appréhender. Le présent travail de thèse propose d'aborder ce problème en intégrant deux types d'approches. D'abord, une approche théorique par homogénéisation du milieu renforcé conduisant in fine à des outils d'aide à la conception. Ensuite, une approche expérimentale comprenant d'une part le recueil de données in situ obtenues grâce à l'instrumentation d'un chantier et d'autre part, des essais sur modèle réduit en laboratoire pour compléter mais aussi pour fournir des données sous conditions idéales plus facile à interpréter
The reinforcement of tunnels face using longitudinal fibre glass bolts allows the excavation in weak ground. Although this technique is employed more and more, the real effect of the bolts on the increase of stability and the reduction of the movements behind the tunnel face remains still difficult to evaluate. This thesis work proposes to tackle this problem using two types of approaches. First, a theoretical approach by homogenisation of the reinforced medium leading to useful design tools. Then, an experimental approach including, on the one hand in situ data obtained thanks to the instrumentation of a real tunnel and on the other hand, experiments using a reduced-scale model in laboratory to complete but also to provide data under ideal conditions easier for the interpretation

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Trompille, Virginie Wong Henry Kwai-Kwan. "Etude expérimentale et théorique du comportement d'un tunnel renforcé par boulonnage frontal." Villeurbanne : Doc'INSA, 2005. http://docinsa.insa-lyon.fr/these/pont.php?id=trompille.

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22

Dounia, Salim. "Optimisation des performances de capteurs de champ à base de jonctions tunnel magnétiques." Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALY025.

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Les capteurs de champ magnétique à base de jonctions tunnel magnétiques constituent une solution prometteuse dans le cadre du développement de dispositifs miniatures de basse consommation. Les performances de ces capteurs dépendent fortement de l’état magnétique (macrospin ou vortex) et des dimensions de la couche libre. Crocus Technology entreprise partenaire de cette thèse conçoit depuis plusieurs années des capteurs à base de jonctions tunnel. Malgré leur très bonne sensibilité, les capteurs dont la couche libre est à l’état macrospin, présentent un bruit important, dégradant fortement la capacité à détecter des champs de faible amplitude, et une hystérèse, qui réduit la gamme de mesure. Les travaux de cette thèse se situent dans ce contexte d’amélioration de la détectivité et de réduction de l’hystérèse et sont consacrés à l’étude de capteurs dont la couche sensible est à l’état vortex en vertu du faible bruit et de l’hystérèse réduite générés par ces capteurs. L’objectif est d’améliorer les performances des capteurs à base de jonctions tunnel à l’état vortex en étudiant différentes formes de plots et différents empilements magnétiques via des simulations micromagnétiques et des caractérisations électriques. Les premiers résultats présentés portent sur l’amélioration de la sensibilité sans dégradation de la linéarité pour des capteurs à base de plots non circulaires et les solutions identifiées par simulations micromagnétiques sont vérifiées expérimentalement. La deuxième partie de ce travail concerne la mesure et l’étude du bruit dans ces capteurs pour différentes formes de plots et empilements magnétiques. On montre que la sensibilité et le bruit dans les capteurs sont corrélés et associés à la qualité de l’interface avec la barrière tunnel en MgO. Le rôle des inserts non-magnétiques pour améliorer la détectivité est démontré. La troisième partie de ce travail porte sur la suppression de l’hystérèse dans ces capteurs. On montre par simulations micromagnétiques que l’hystérèse est contrôlée grâce à une entaille au bord des plots. On montre également que des plots elliptiques avec méplat permettent d’augmenter la gamme de mesure. Une hystérèse résiduelle est néanmoins générée par la présence de l’entaille. On développe par la suite un modèle analytique permettant de confirmer les résultats de simulations et de déterminer les dimensions des plots et du méplat permettant de supprimer cette hystérésis. Finalement, la dernière partie de ce travail porte sur la suppression de l’hystérèse résiduelle via l’interaction magnétostatique entre plots voisins dans une matrice indépendamment de la forme du plot et de l’entaille. Un modèle analytique est développé pour étudier cette interaction mais il doit encore être amélioré afin de confirmer les résultats de simulations
Magnetic field sensors based on magnetic tunnel junctions are a promising solution in the development of miniature low power devices. The performances of these sensors are highly dependent on the free layer dimensions and thus it’s magnetic state (macrospin/vortex). Crocus Technology, the industrial stakeholder of this thesis, has been designing some of the smallest TMR sensors for several years. Sensors at macrospin state, despite their good sensitivity, have a high noise level strongly degrading their ability to detect low magnetic fields, and an undesired hysteresis. This thesis takes place in this context of improving detectivity and reducing hysteresis. It focuses on the study of TMR sensors with a free layer at vortex state to take advantage of the low noise and reduced hysteresis expected for this magnetic state. The objective is to improve the performances of these TMR sensors by studying different dot shapes and magnetic stacks via micromagnetic simulations and electrical characterizations. The first results presented in this thesis concern the improvement of sensitivity without degradation of linearity for sensors based on non-circular dots; experiments confirm the validity of the solutions obtained by micromagnetic simulations. The second part of this work concerns the measure and study of noise and detectivity for different dot shapes and magnetic stacks. We show that noise and sensitivity are correlated and that noise is linked to grains at the interface with MgO tunnel barrier. In particular, we demonstrate that non-magnetic inserts improve detectivity. The third part of this work deals with hysteresis reduction in these sensors. Using micromagnetic simulations, we show that hysteresis can be controlled thanks to a cut at the dot edge. We also note that elliptical dots with a flat cut improve the measuring range. A residual hysteresis is however generated by the cut. An analytical model is then developed in order to confirm simulations results and to determine dots geometry leading to hysteresis suppression. Finally, the last part of this work deals with the suppression of the residual hysteresis via the magnetostatic interaction between neighbouring dots independently of their shape. An analytical model is developed but needs further improvements to confirm simulation results

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Barros, Oscar de. "Caractérisation électrique des défauts induits lors de l'intégration de la base d'un transistor bipolaire a hétérojonction SIGe en technologie BICMOS." Lyon, INSA, 1997. http://www.theses.fr/1997ISAL0106.

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Les progrès des techniques d'épitaxie ont permis la fabrication de couches de SiGe contraint sur substrat silicium et leur mise en application dans des transistors bipolaires à hétérojonction, permettant à la technologie silicium d'atteindre des performances dynamiques intéressantes pour les applications haute fréquence. Toutefois l'intégration de l'alliage SiGe dans: une filière doit répondre au double impératif de qualité finale de l'alliage et de perturbation minimum à apporter à la filière technologique. C'est dans cet objectif et dans le cadre de l'intégration du TBH SiGe dans une filière BiCMOS développée au CENT Meylan que s'inscrit ce sujet de thèse. Au cours de ce travail, nous avons étudié la qualité du système émetteur-base des transistors bipolaires à hétérojonction à base SiGe à l'aide• de techniques de caractérisation électrique, mesure de courant statique et spectroscopie de transitoire. Les résultats expérimentaux obtenus sur des transistors simple-polysilicium auto-alignés ont mis en évidence la présence de défauts dans la zone active du composant, localisés à la périphérie de la jonction émetteur-base le long des espaceurs Si02. L'énergie d'activation apparente de ces pièges est de 0,6 eV, ce qui en fait des centres de recombinaison très efficaces. Ces défauts ayant pu être corrélés à l'étape de gravure lors de la définition du système émetteur-base, la qualité cristalline des couches épitaxiées n'est donc pas dégradée par le process post-épitaxie. Ce résultat est une contribution au choix d'une nouvelle architecture pour les filières développées plus récemment, dans laquelle la zone active est éloignée des zones gravées. Les études initiées sur les transistors simple-polysilicium quasi auto- alignés de cette filière montrent la présence de plusieurs niveaux profonds dans la base du composant, ce qui est un point critique pour le bon fonctionnement de ces composants
Epitaxial growth improvements have allowed the elaboration of high quality SiGe strained layers on Si substrate and their application in heterojunction bipolar transistors, leading silicon based devices to high frequency performances. Nevertheless, the integration of the. SiGe alloy in an industrial process requires minimum process modification as well as a high final quality of epitaxial layers. This is the context of the SiGe HBTs integration into a BiCMOS process developed at the CNET Meylan. In this thesis work, we present a study of the quality of the emitter-base system of SiGe HBTs, by means of electrical measurements such as deep level transient spectroscopy and static currents. Experimental results on single polysilicon self-aligned transistors point out the presence of defects in the active zone of the devices, located at the emitter-base junction periphery along Si02 spacers. The apparent activation energy is 0. 6 eV, making these deep levels very active recombination centers. These defects have been shown to originate from the reactive ion etching of the polysilicon emitter, leading to the conclusion that the epitaxial layers do not suffer relaxation during the process. This result is a contribution to the choice of a quasi-self-aligned structure for further development, where the active zone is far from etch-induced damages. First results concerning the quasi self-aligned transistors have evidenced the presence of many deep levels in the SiGe base bandgap, corresponding to defects at the Si/SiGe interface and in the SiGe base, which dramatically degrade the device performances

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Di, Pendina Grégory. "Conception innovante et développement d'outils de conception d'ASIC pour Technologie Hybride CMOS / Magnétique." Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENT035/document.

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Depuis plusieurs années de nombreuses technologies non volatiles sont apparues et ont pris place principalement dans le monde de la mémoire, tendant à remplacer tout type de mémoire. Leurs atouts laissent à penser que certaines d'entre elles, et en particulier les technologies MRAM, pourraient améliorer les performances des circuits intégrés en utilisant leurs composants magnétiques, si connus notamment sous le nom de jonctions tunnel magnétiques, dans la logique. Pour évaluer ces éventuels gains, il faut être capable de concevoir de tels circuits. C'est pourquoi nous proposons dans ces travaux d'une part un kit de conception complet pour les flots de conception full custom et numérique, permettant de couvrir l'ensemble des étapes de conception pour chacun d'entre eux. Une partie de ce kit a servi à plusieurs partenaires de projets de recherche ANR, pour concevoir des démonstrateurs. Nous proposons également dans ce kit de conception un latch magnétique non volatil innovant ultra compact, pour lequel deux brevets d'invention ont été déposés, intégré à une flip-flop. Enfin, nous présentons l'intégration de composants magnétiques à deux applications, sécurité et faible consommation, ainsi qu'une étude qui montre que les gains en consommation statique peuvent être considérables
For several years many non-volatile technologies have been appearing and taking place mainly in the memory world, aiming at replacing all kind of memory. Their assets let thinking that some of them, specially the MRAM technologies, could improve the integrated circuit performances, using their so called magnetic components in the logic, in particular the magnetic tunnel junctions. To evaluate the potential benefits, it is necessary to be able to design such a circuit. That is the reason why we are proposing a full design kit for both full custom and digital designs, allowing all the design steps. Part of this kit has been used by partners in research project to design demonstrators. We also propose in this kit an innovative ultra-compact magnetic latch, for which 2 patents have been deposited, integrated in a flip-flop. Finally, we present the integration of magnetic components for two applications, security and low power, as well as a case study which shows that the static consumption reduction can be huge

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Unlu, Mehmet. "Novel Impedance Tuner, Phase Shifter, And Vector Modulators Using Rf Mems Technology." Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/4/12610502/index.pdf.

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This thesis presents the theory, design, fabrication, and measurement results of novel reconfigurable impedance tuner, phase shifter, and vector modulators using the RF MEMS technology. The presented circuits are based on triple stub topology, and it is shown both theoretically and experimentally in this thesis that it is possible to control the insertion phase and amplitude of the input signal simultaneously using this topology. The presented circuits are implemented using an in-house, surface micromachining fabrication process developed at METU, namely METU RF MEMS Fabrication Process, which is implemented using six masks on quartz substrates. The RF MEMS impedance tuner is designed to operate in 6-20 GHz frequency band, and it covers the Smith Chart with 1331 impedance points. The measurement results of 729 impedance points of the fabricated impedance tuner show that a wide Smith Chart coverage is obtained in the entire band. The RF MEMS phase shifter is designed to cover 0-360 degrees range 10 degree steps at 15 GHz center frequency. The measurement results of the fabricated phase shifter show that the average phase error is 1.7 degrees, the average insertion loss is -3.1 dB, and the average return loss is -19.3 dB for the measured 21 phase states. The phase shifter can also work up to 30 GHz and 40 GHz with average insertion losses of -5 dB and -8 dB, respectively. The designed RF MEMS vector modulator operates in 22.5-27.5 GHz band, and it has 3 amplitude and 8 phase states. The measurement results of the fabricated vector modulator show that the amplitude error is 0.5 dB, the phase error is 4 degrees, and the return loss is -15 dB on average among the 24 measured states at each of 22.5, 25, and 27.5 GHz frequencies.

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Kilburn, Lilia Maud. "Answering machine, auto-tune, spectrograph : queer vocality through sonic technology." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/106760.

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Thesis: S.M. in Comparative Media Studies, Massachusetts Institute of Technology, Department of Humanities, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 113-121).
In academic and activist contexts, "voice" has long served as shorthand for inclusion, empowerment, and the like, occasioning bromides about having or not having a voice, giving voice to the voiceless, breaking the silence, and speaking truth to power. Such metaphysically inflected phrasings often serve to reinforce a binary between sound and silence at the expense of attending to other vocal modulations. This thesis first assembles calls by queer and feminist scholars for such nuanced portrayals of vocality; then, so as to answer those calls, it stages scenes of listening. I examine vocality through technology: by looking at how vocality is structured by enclosing technologies, which in turn structure relations and the reverse. More specifically, my thesis traces the ways in which vocality travels in the world by attending to three particular technologies through which the voice is filtered: the answering machine, Auto-Tune pitch correction software, and the sound spectrograph. This approach enables me to probe the distinct claims that specific sound technologies allow us to hold on one another-claims about mourning and loss, about calling and the promise of response, about the identification of individuals (or oneself) via the voice. Though my investigations span various archives, I center them on two characters: the performer Cher and her son Chaz, who is transgender. I do so to consider the ways in which a sonically inflected media theory can inform queer theory and vice versa, and to consider the particular relational dilemmas made incumbent upon subjects whose vocal trajectories are discontinuous, depart from normative pitch, and/or deemed an invitation to violence.
by Lilia Maud Kilburn.
S.M. in Comparative Media Studies

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Couturaud, Olivier. "Effets tunnels dans des nano-capteurs de Hall." Montpellier 2, 2008. http://www.theses.fr/2008MON20122.

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Dans le cadre de cette thèse, nous avons étudié une famille de capteurs à effet Hall, composé de croix de Hall submicroniques et de microgradiomètres réalisée à partir d'hétérostructures à puits quantiques optimisées. De par leurs performances, ces capteurs pourraient permettre d'aborder de façon plus efficace, l'étude à l'échelle nanométrique, des propriétés magnétiques de la matière micro- et nanostructurée, ainsi que celles des nanocomposants. La première partie de cette thèse est consacrée à la fabrication et à la caractérisation des capteurs. On étudiera tout d'abords les résistances de contacts et les largeurs de déplétion limitant le fonctionnement des capteurs puis on s'intéressera à la métrologie des composants. Dans la seconde partie, on étudie le passage par effet tunnel des électrons entre les bords de l'échantillon. En régime d'effet Hall Quantique, il apparaît des fluctuations aux extrémités des plateaux à la fois sur les résistances transverses et longitudinales. Les pics sur le côté fort champ de la transition sont différent de ceux situé sur le côté faible champ de la transition. Il diffère aussi par leur comportement en température. Du côté des fort facteurs de remplissage, l'évolution en température des pics permet de les relier à un effet tunnel résonnant à travers un état créé par un des antidots se formant lors du remplissage des niveaux de Landau. Du côté des faibles facteurs de remplissage, la dépendance en température est différente et est reliable à un processus de "Variable Range Hopping". Ces processus peuvent être reliés à l'assymétrie de la densité d'états
As part of this thesis, we studied a family of Hall effect sensors , composed of submicrometers Hall cross and microgradiometers made from optimized quantum wells. The first one left this thesis is dedicated to manufacture and to characterization of sensors. They will study everything of manners the resistance of contacts and the depletion length restricting the functioning of sensors In second part, we study the tunnel effect of electrons between the edges of the sample. In the presence of a quantizing magnetic field, at the transition between two quantized Hall plateaus, a succession of sharp peaks is detected in the Hall signal RH and in the longitudinal resistance RL. The peaks appearing on the high-í side of the RL transition appear to be different from the peaks appearing on the low-í side. They mainly differ by their temperature dependence. On the high-í side of the RL transition, the temperature evolution of the peaks is typical for resonant tunneling through a single state in one of the antidots that are progressively formed when the initially occupied LL is emptied. On the low í of the transition, by contrast, the temperature dependence is different. This may be related to the asymmetry of the density of states

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Chahboun, Adil. "Etude d'électrons balistiques en microscopie à effet tunnel et autres applications en microscopie à champ proche." Toulouse 3, 1992. http://www.theses.fr/1992TOU30212.

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Quand un metal vient au contact d'un semi-conducteur, il y a formation d'une barriere de potentiel appelee la barriere de schottky. Cette barriere energetique joue un role important sur les performances des instruments a base de semi-conducteur. Une manipulation derivee de la microscopie a effet tunnel (beem) permet la mesure de la hauteur de cette barriere avec une resolution nanometrique. Durant cette these, nous avons realise cette manipulation et avons applique a l'etude d'une jonction au/si. Des phenomenes originaux ont ete observes, telle la saturation du spectre beem a fortes tensions de polarisation tunnel, la dependance de la geometrie d'injection electronique de la cristallographie du film metallique. L'etude de membranes d'ultrafiltration par stm, afm et sem a montre que le stm et l'afm peuvent etre consideres comme deux outils efficaces pour la caracterisation de ces materiaux. Les effets de la pointe sur la reproduction de surfaces rugueuses ont ete mises en evidence. L'observation de microtubules par stm a permis de deceler une eventuelle sous-structure de la tubuline, molecule unite des microtubules

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Chinien, Lomadeven Viken. "Design of multiple tuned mass dampers for mitigation of wind induced vibrations." Thesis, Imperial College London, 2000. http://hdl.handle.net/10044/1/11536.

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Grigoriou, Eleni. "Graded organisation of fibronectin to tune cell behaviour." Thesis, University of Glasgow, 2017. http://theses.gla.ac.uk/8523/.

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Cells are in constant and dynamic interactions with the extracellular environment. They receive several inputs involved in the regulation of cell behaviour. Fibronectin, an abundant protein of the ECM, contains multiple binding domains and binds to cell receptors, growth factors and other ECM proteins. FN undergoes conformational changes through cell-generated contractile forces which consequently affects cell response. Tissue engineering aims at engineering biomaterials that recreate the in vivo ECM. In addition to biomaterials, stem cells have emerged as a promising source due to their inherent differentiation potential. In this work, the role of poly acrylates in controlling human mesenchymal stem cell behaviour (hMSCs) was explored. Particularly, a series of copolymers with specific ratio of ethyl(acrylate), EA, and methyl(acrylate), MA, were used. It is known that poly(ethyl)acrylate, PEA, triggers a network-like conformation of FN upon adsorption, whereas poly(methyl)acrylate, PMA, elicits a globular conformation. It was found that a different degree of FN organisation can be obtained dependent on the EA/MA ratio, with the network being more connected with increased EA ratio. This differential conformation was shown to affect the availability of critical binding sites. This system was further used to study hMSCs response in terms of adhesion and osteogenic differentiation. All surfaces support cell growth and focal adhesion formation. However, increased cell size and spreading was promoted on surfaces with higher EA concentration. Next, the potential of the surfaces after sequential adsorption of FN and the growth factor BMP-2 to drive osteogenic commitment was explored. Enhanced expression of the osteogenic markers RUNX2 and OCN was found with higher concentration of EA whereas the opposite was observed with ALP expression. Another part of this work involved investigating cell migration on PEA and PMA. Higher cell speed was found on PEA where FN adopts a more extended conformation. Moreover, the protein composition of focal adhesions was evaluated by proteomic analysis. The findings of this work give further insights into how the surface with well-defined chemical properties can modulate FN conformation and how these changes affect cellular processes.

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Skiribou, Camelia. "Canal de propagation 5G et mécanisme de contrôle d'intégrité : application à la localisation sûre des rames dans un tunnel." Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS343.

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Le développement de toute nouvelle technologie sans fil passe par une phase de simulation système, afin d’identifier les paramètres qui impactent la qualité de transmission et de définir les limites du réseau. Ces simulateurs doivent reposer sur des modèles de canaux précis et réalistes permettant de mieux prédire les indicateurs de performance du système. La future génération des réseaux mobiles 5G, en cours de standardisation pour un déploiement en 2020, n’en est pas une exception. Afin d’assurer une communication optimale en termes de ressources énergétiques et spectrales, la nouvelle génération des terminaux 5G doit être également en mesure de connaître en permanence son environnement. Cela repose sur l’implémentation d’un système de localisation, notamment dans les milieux contraints où les systèmes de positionnement satellitaires ne sont pas disponibles. Dans le domaine des transports, un exemple assez récurent est celui des tunnels. Ce type d’environnement est caractérisé par le phénomène de guidage d’onde dû à sa structure géométrique et des propriétés des matériaux de ses murs. Une extension des modèles de propagation développés pour les systèmes 5G s’avère nécessaire, afin de prendre en considération ce cas d’usage. Le modèle proposé dans le cadre de cette thèse adopte une approche hybride pour reproduire l’effet du canal dans une chaîne de localisation. Dans un premier temps, les paramètres de propagation sont calculés par un simulateur à tracé de rayons. Les données déterministes obtenues sont analysées afin d’identifier les lois statistiques qui les régissent. Cela permet de créer une base de données contenant pour chaque paramètre la distribution qui lui correspond. Cette dernière est utilisée pour générer d’une manière stochastique les coefficients du canal utiles à notre système de localisation, à savoir l’amplitude et le retard relatifs à chaque trajet. La réponse impulsionnelle du canal servira à estimer la distance entre les deux antennes de transmission. En fonction des conditions de propagation ainsi que de la position du récepteur, trois sources d’erreur peuvent compromettre la précision de cette distance. Elles sont liées à sa largeur de bande, son seuil de détection, et à l’obstruction éventuelle du trajet direct. L’implémentation d’un mécanisme de contrôle d’intégrité s’annonce comme une solution prometteuse pour améliorer les performances de notre système. Ce dernier consiste à identifier les mesures aberrantes ne répondant pas aux contraintes imposées par l’application, puis de les exclure ou les corriger en fonction de la stratégie adoptée par le récepteur. Dans ce contexte, nous proposons d’exploiter la diversité spatiale d’un système SIMO (pour Single Input Multiple Output) à deux antennes de réception afin d’identifier les conditions de propagation du canal. La première étape de notre approche a pour but d’augmenter la résolution temporelle des deux réponses impulsionnelles du système. Ces dernières sont reconstruites dans le domaine fréquentiel sur une très large bande grâce à une technique de « compressed sensing ». Elles sont ensuite classifiées selon un critère temporel. Celui-ci représente la différence des temps de propagation du signal dans chacun des deux canaux, et il est obtenu par l’intercorrélation des réponses impulsionnelles reconstruites. L’approche proposée permet d’améliorer la fiabilité de l’information de localisation dans le tunnel et de réduire l’erreur liée à la bande limitée du système et à l’absence du trajet direct. Une implémentation expérimentale de la chaîne de localisation basée sur des signaux OFDM donne lieu à des erreurs d’estimation de distance au moins six fois inférieures à celles reportées par l’approche classique, ou même à celles relatives aux autres techniques d’identification basées sur les tests statistiques. Cet algorithme constitue, avec le modèle hybride du canal, les deux contributions majeures de ce travail de thèse [...]
System level simulations are crucial in the development phase of any emerging wireless technology. It allows to identify the key factors that affect the transmission quality and to define the network limits. The used simulators must then be based on accurate and realistic channel models to better predict the system performances. In this context, several researches had been interested to the development of new models that take into account the emerging propagation scenarios introduced by the fifth generation of mobile communications (5G) that will be commercialized by 2020. In order to optimize the spectral and energetic resources use, the mobile terminals of this next generation should be constantly aware of their environment. This relies on the implementation of a location system, especially in constrained environments where satellite positioning systems are not available. In the field of transport, a rather recurrent example of these scenarios is that of tunnels. Although they are indoor environments, this type of environment is characterized by the phenomenon of wave guiding due to its geometric structure and the properties of the materials of its walls. Thus, an extension of the propagation models developed for the 5G systems is then necessary, in order to take into account this use case. We propose in this thesis a hybrid approach to reproduce the effect of the channel in a localization system. First, we calculate the propagation parameters by a ray-tracing simulator. It accurately describes the behavior of the radio waves inside the tunnel; nevertheless, it is expensive in terms of computing time. Then we analyze the obtained deterministic data to identify their statistical laws, and we store both of them in a database to stochastically generate the channel coefficients needed for our ranging system, namely the amplitude and the delay relative to each path. The impulse response of the channel will finally be used to estimate the distance between the two transmission antennas. Depending on the propagation conditions as well as the position of the receiver, three sources of error can compromise the accuracy of this distance. For a ranging system based on the time metric, they are related to the bandwidth, the detection threshold, and the obstruction of the direct path. The implementation of an integrity control mechanism seems to be a promising solution to improve the performance of our system. It then consists of identifying the outliers that do not meet the constraints imposed by the application, then excluding or correcting them according to the strategy adopted by the receiver. In this context, we propose to exploit the spatial diversity of a SIMO (Single Input Multiple Output) system with two reception antennas in order to identify the propagation conditions of the channel. The first step of our approach aims to increase the temporal resolution of the two impulse responses of the system. Being sparse, they are reconstructed in the frequency domain over a very wide band using a compressed sensing technique. Then we classify them according to a temporal criterion, which represents the time difference of propagation of the signal in each channel, and we obtain it by the inter-correlation of reconstructed impulse responses. The proposed approach not only improves the reliability of the ranging information in the tunnel, but also reduces the error related to the limited bandwidth of the system and the obstruction of the direct path. An experimental implementation of the ranging system based on OFDM signals gives rise to distance estimation errors at least six times lower than those reported by the classical approach, or even to those issued from other identification techniques based on statistical tests. This algorithm and the hybrid model of the channel are then the two major contributions of this thesis work [...]

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Giones, Valls Ferran. "Turn On, Tune In, Drop Out? Exploring the Venture Emergence in Technology-based Firms." Doctoral thesis, Universitat Ramon Llull, 2016. http://hdl.handle.net/10803/361123.

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Els emprenedors prenen decisions com la d’engegar o no la seva idea de negoci, adaptar-se i ajustar-se a les peticions del mercat, i desafortunadament la de continuar o deixar el procés de creació del nou negoci. Tot i que la constant progressió tecnològica obre oportunitats als emprenedors per engegar idees de negoci en base a noves innovacions tecnològiques, només alguns d’ells i elles aconsegueixen complir amb aquestes expectatives. Les investigacions prèvies en emprenedoria s'han centrat en entendre com els recursos poden explicar l'evolució de les empreses de nova creació. No obstant, quan es planteja l’estudi de l’emprenedoria de base tecnològica trobem dificultats per poder explicar les diferències de resultats si només ens fixem en les combinacions de recursos inicials. Aquesta recerca proposa introduir altres perspectives teòriques que ens poden ajudar a identificar factors per entendre millor com sorgeixen les organitzacions de base tecnològica. Fem servir un mètode mixt, combinant un estudi qualitatiu exploratori amb un estudi quantitatiu. En primer lloc explorem factors i accions que influencien el procés d’emprenedoria tecnològica. Seguidament, ampliem el marc teòric inicial per donar suport als aspectes que han aparegut en el treball qualitatiu, i formular les hipòtesis de recerca. Fem servir un set de dades longitudinals per testejar aquestes hipòtesis. Finament, es conclou el document reflexionant sobre la combinació dels resultats del treball qualitatiu i quantitatiu. Utilitzant la teoria de senyals expliquem que els recursos tecnològics poden tenir una funció com a símbol diferencial de qualitat. Observem que aquests recursos han de ser transformats per tal de generar valor pels potencials clients. Fent servir la perspectiva teòrica de màrqueting i del capital humà es detalla com l’experiència i la intensitat de les seves accions de creació de mercat tenen una influència positiva en el procés de sorgiment. Aquesta recerca contribueix al coneixement actual sobre el desenvolupament de les empreses de nova creació de base tecnològica. Es suggereix que l’orientació de les accions de l’emprenedor, en concret l’activació de capacitats d’interacció amb el mercat, influeixen en sorgiment d’aquest tipus d’organitzacions. Els resultats també tenen implicacions pràctiques per emprenedors, inversors i agents implicats en el desenvolupament d’emprenedoria tecnològica; es proposa que més enllà d’analitzar les combinacions inicials de recursos d’un emprenedor, s’ha de dedicar més atenció a la capacitat de transformar aquests recursos en propostes de valor, i la seva orientació a mercat.
Los emprendedores toman decisiones como la de empezar o no su idea de negocio, adaptarse o no a las necesidades del mercado, y desafortunadamente la de continuar o dejar su proyecto. A pesar de que la constante progresión tecnológica abren oportunidades para generar ideas de negocio a partir de las innovaciones tecnológicas; sólo algunos de ellos y ellas logran cumplir estas expectativas. Las investigaciones previas en emprendimiento han observado como los recursos pueden ayudar a entender la evolución de las empresas de nueva creación. No obstante, cuando se plantea el estudio del emprendimiento de base tecnológica nos encontramos con dificultades para poder explicar las diferencias de resultados si nos limitamos a observar las combinaciones iniciales de recursos. Esta investigación propone introducir perspectivas teóricas que nos permitan identificar factores y su influencia para entender como surgen las organizaciones de base tecnológica. Utilizamos un método mixto, combinando un estudio cualitativo y un cuantitativo. En primer lugar exploramos factores y acciones que influyen en el proceso de emprendimiento tecnológico. A continuación ampliamos el marco teórico inicial para dar soporte a los aspectos identificados en el trabajo cualitativo, y formulamos las hipótesis de investigación. Usamos un set de datos longitudinales para testeas estas hipótesis. Finalmente, se concluyen el documento con una discusión de los resultados obtenidos. La teoría de señales nos permite entender como los recursos tecnológicos pueden tener una función como símbolo de calidad. Observamos que estos recursos deben ser transformados para generar valor para los potenciales clientes. Utilizando la perspectiva teórica de marketing y de capital humano detallamos como la experiencia y la intensidad de las acciones de creación de mercado tienen una influencia positiva en el proceso de creación de las empresas. Esta investigación contribuye al conocimiento actual sobre el desarrollo de empresas de nueva creación de base tecnológica. Se sugiere que la orientación de las acciones del emprendedor, en concreto la activación de orientación a mercado, influyen en desarrollo de estas organizaciones. Los resultados tienen implicaciones prácticas para emprendedores, inversores y agentes implicados en el desarrollo de emprendimiento tecnológico; se propone que más allá de fijarse en las combinaciones iniciales de recursos, debemos dedicar más atención a las capacidades de transformar estos recursos en propuestas de valor y su orientación a mercado.
Despite the remnant promises that sustained technological progress offers to entrepreneurs eager to introduce disruptive technological innovations, we observe that only few of them live up to the expectations. In fact, there is a limited understanding on the factors underlying the transformation of promising technologies into viable organizations, and how they influence the decisions to turn on, tune in with the market, and drop-out or continue with their organizing efforts. Prior entrepreneurship research relying on the resource-based view finds difficulties to explain the technology-based firms' performance. We propose to complement the current understanding with additional perspectives that could help to identify factors that provide further insights on the emergence of new technology-based firms. We adopt a mixed-method approach to combine an exploratory qualitative field work with a quantitative research approach. First, we gather insights on the factors and actions that are seen to be influencing the technology entrepreneurship process, from the initial opportunity to the creation of a stable business. Then, we extend our initial theoretical framework on the technology entrepreneurship process to support the qualitative findings and build propositions; these are tested as hypotheses on a larger sample of technology-based firms. Finally, we combine the findings from the qualitative field work with the findings from the hypotheses test. Using the signaling theory we explain how some resources value goes beyond its direct impact on firm’s performance, suggesting that they are also used for their symbolic value. We observe that technological assets need to be transformed in order to generate value for the potential customers of the new venture. Marketing and human capital theory insights provide an explanation on how experience and market presence positively influence the venture emergence of new technology-based firms. We contribute to the current understanding of new technology-based firms with the introduction of human capital, marketing and technology commercialization theory. Describing how the orientation of entrepreneur's actions and the early development of market capacities influence on the venture emergence of this type of firms. The results also have implications for entrepreneurs, investors in technology startups, and stakeholders in technology entrepreneurship; as they suggest that further attention should be given to the market actions of the entrepreneurs, regardless of their initial combinations of resources.

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Di, pendina Gregory. "Conception innovante et développement d'outils de conception d'ASIC pour Technologie Hybride CMOS / Magnétique." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00750121.

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Depuis plusieurs années de nombreuses technologies non volatiles sont apparues et ont pris place principalement dans le monde de la mémoire, tendant à remplacer tout type de mémoire. Leurs atouts laissent à penser que certaines d'entre elles, et en particulier les technologies MRAM, pourraient améliorer les performances des circuits intégrés en utilisant leurs composants magnétiques, si connus notamment sous le nom de jonctions tunnel magnétiques, dans la logique. Pour évaluer ces éventuels gains, il faut être capable de concevoir de tels circuits. C'est pourquoi nous proposons dans ces travaux d'une part un kit de conception complet pour les flots de conception full custom et numérique, permettant de couvrir l'ensemble des étapes de conception pour chacun d'entre eux. Une partie de ce kit a servi à plusieurs partenaires de projets de recherche ANR, pour concevoir des démonstrateurs. Nous proposons également dans ce kit de conception un latch magnétique non volatil innovant ultra compact, pour lequel deux brevets d'invention ont été déposés, intégré à une flip-flop. Enfin, nous présentons l'intégration de composants magnétiques à deux applications, sécurité et faible consommation, ainsi qu'une étude qui montre que les gains en consommation statique peuvent être considérables.

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Maasoglu, Goncagül. "Kan den fysiska miljön underlätta brott? : Lärdomar från en systematisk analys i Bergsjön, Rinkeby och Vivalla." Thesis, KTH, Samhällsplanering och miljö, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-232993.

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Det pågår många brottsförebyggande arbeten idag i Sverige och dessa sker oftast genom sociala insatser, men det är allt för få satsningar som avser den fysiska miljön. Den påverkar oss människor mer än vad vi tror. Syftet med denna studie är att göra en systematisk analys av den fysiska miljön i tre särskilt utsatta områden och undersöka hur dessa miljöer kan skapa brottsmöjligheter. Områdena Bergsjön, Rinkeby och Vivalla undersöks i denna rapport, dessa är valda till särskilt utsatta områden och där finns en rådande problematik och även en högre koncentration av kriminella (Polisen, 2017). Fakta och teorier som bland annat rutinaktivitetsteorin, CPTED och Jane Jacobs stadsplaneringsidéer behandlas i studiens bakgrund. Likheterna mellan områdenas fysiska miljöer sammanställs genom kartjämförelser, platsanalyser och intervjuer. Metoden visade att trafiksepareringen hade skapat många mörka gångtunnlar in till områdena som skapade oattraktiva och otrygga inträden. Att områdena var bilfria ledde ytterligare till att många ställen blev ödsliga, obevakade och otrygga. Områdenas byggnader var vidare inte varierade och det kunde förekomma flera likadana hus bredvid varandra, till och med över hela områden. För en brottsling är det enklare att begå brott i en enkel detaljfattig miljö, eftersom det då är färre saker att hålla koll på och det blir mycket enklare att begå brottet när övriga människor inte ser sig omkring sig. En annan likhet var gatustrukturen, till exempel hade de tre områdena återvändsgator som inte sammanvävde vägarna med varandra. Detta bidrog till segregerade områden och svårigheter för polisen att komma fram och utföra sina insatser på ett effektivt sätt. Även byggnadernas placering mot gatan påverkade huruvida det skapades naturlig övervakning som kunde motverka brottslighet. Därmed blev slutsatsen att likheterna i den fysiska miljön mellan de tre områdena kan underlätta möjligheterna för att begå brott.
There is many jobs today in Sweden for crime prevention and these happen often through social efforts, but there is way too few of these for the physical environment that actually affects us more than we think they do. The purpose with this study is to make a systematical analysis of the physical environment in three deprives areas and examine if these environments can create crime opportunities. The chosen places are Bergsjön, Rinkeby and Vivalla with current problematic and high crime concentration (Polisen, 2017). Fact and theories such as the Routine Activity Theory, CPTED and Jane Jacobs’s urban ideas is treated in the study’s background. Similarities between the areas physical environment is compiled through map comparisons, place analysis and interviews. The methods result showed that the traffic separation created many dark tunnels into the areas, which caused unattractive and insecure entries. The buildings in the areas were also not varied and there could be a several of similar houses next to each other or over the whole field. It can be easier for a criminal to commit crimes in a simple surrounding without details, because it is fewer things to keep track of and it becomes much easier to commit the crime when people doesn’t look around themselves. Another similarity was the street structures, for example the three areas had blind alleys that didn't interweave the streets with each other. This contributed to segregated areas and difficulties for the police to arrive and perform their efforts effectively. Even the buildings placement to the street affected whether they had a natural surveillance that could prevent crime. This concluded that the physical environment in these three deprived areas can affect the emergence of crime.

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Prasetiadi, Ananto Eka [Verfasser], Rolf [Akademischer Betreuer] Jakoby, and Michael [Akademischer Betreuer] Höft. "Tunable Substrate Integrated Waveguide Bandpass Filter and Amplitude Tuner Based on Microwave Liquid Crystal Technology / Ananto Eka Prasetiadi ; Rolf Jakoby, Michael Höft." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2017. http://d-nb.info/114058670X/34.

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Jansson, Anna. "Ljuset i tunneln : En studie i hur ljus och färg kan utformas, i syfte att erbjuda en tryggare känsla för fotgängare i befintliga gångtunnlar." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-36306.

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Många människor i dagens samhälle upplever att de känner sig otrygga när de rör sig i utvalda delar av staden. Detta är ofta platser som saknar tillräcklig ljussättning eller känns bortglömda i stadsrummet. En utav dessa platser är den miljö i stadens befintliga gångtunnlar som ibland inte används, på grund av personers rädsla för att vistas i dessa, trots att deras främsta syfte är just trygghet för fotgängare i stadsmiljöer. I denna studie undersöks hur ljus och färg kan användas som kommunikationsmedel, i syfte att skapa en tryggare känsla för användarna av dessa otrygga tunnlar. Arbetet har genomgått metoder som användarundersökning, intervju med sakkunnig och rumsliga observationer för att svara på forskningsfrågan. Teorier inom trygghetsfrämjande element har studerats, så väl som ljuset och färgens effekter på välbefinnande, samt kommunikativa förmåga. Ljuset i tunneln är ett examensarbete inom området för Informationsdesign och Rumslig gestaltning. Den slutgiltiga gestaltningen syftar till att informera de som arbetar med trygghetsarbete i form av ljus och färg, om vilka riktlinjer som bör finnas i åtanke i projektet, för att täcka användarna av dessa miljöers behov.
Many people in today’s society feel unsafe while walking in specific parts of a city. This may be the result in lack of lightning in these spaces, and it’s possible that these spaces don’t communicate a safe passage for the users. This study aims to investigate how light and colour can be configured to communicate and conjure a safe passage through the experienced unsafe places. One of these unsafe places are pedestrian tunnels, who might not be used as thought, due to the anxiety of usage. Even thou these tunnels actually exist to bring safety to pedestrians in the city. This thesis has implemented through different methods such as user survey, interview with expertise, and spatial observation, in order to achieve new insight into this research. An already existing tunnel in Eskilstuna partly known for its lack of lightness, will serve as my case study for this Bachelor thesis in Information design, emphasis in Spatial design.

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Persson, Daniel. "Visualisering av amyloider och patogenes i skadad näthinna." Thesis, Högskolan Kristianstad, Sektionen för lärande och miljö, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hkr:diva-17218.

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Ansamling av amyloid beta (Aβ) i de extracellulära miljöerna är associerad till många svåra sjukdomar som Alzheimers och ålders-relaterad makuladegeneration (AMD). Amyloider karaktäriseras av att de är olösliga, toxiska mot neuron och orsakar därför svår skada. AMD är den ledande orsaken till blindhet och irreversibelt förlorande av skarp syn då Aβ manifesterar i makula. I AMD orsakar Aβ inflammatorisk aktivitet där det retinala pigmentepitelet bryts ned och ljuskänsliga fotoreceptorer dör genom apoptos. Idag lever ca 150 miljoner människor med AMD där mänga har svårt att utföra vardagliga uppgifter till följd av förlust av skarp syn. Idag är Kongo röd en av de vanligaste metoderna för att visualisera amyloider in vitro. Den patogenes som orsakas av amyloider kan analyseras med immunofluorescens och immunohistokemi. Syftet med studien var att undersöka förekomst av amyloider i samband med celldöd i näthinna från gris, undersöka den patogenes som amyloider orsakar med immunofluorescens och immunohistokemi, samt undersöka om det finns korrelation mellan amyloider och celldöd. Resultatet visade att amyloider var förekommande i näthinnan och hade orsakat celldöd och ansamling av aggresomer. Amyloider och den patologi som orsakats kunde visualiseras i det yttre lagret av näthinnan.
Deposition of amyloid beta (Aβ) in the extracellular environment are associated to some severe diseases, like Alzheimer’s disease and age-related macular degeneration (AMD). Amyloids are characterized by insolubility, toxicity towards neuron and are there-for damaging to tissues. AMD is the primary cause of blindness and irreversible loss of central vision through manifestation of Aβ in the macula. In AMD, Aβ drives an inflammatory action that degenerates the retinal pigment epithelium and cause atrophy of photoreceptors. Today ~150 million people live with AMD where many find difficulties performing everyday tasks due to loss of sharp vision. Congo red is a gold standard for visualizing amyloids in vitro and the pathogenesis caused by amyloids can be analyzed by immunofluorescence and immunohistochemistry. The purpose of this study was to show the presence of amyloids relating to cell death in pig retina, show the pathogenesis caused by amyloids by using immunofluorescence and immunohistochemistry, and investigate whether there is correlation between amyloids and cell death. The result showed that amyloids were present in the retina and caused cell death and gathering of aggresomes. Amyloids and the caused pathology could be visualized in the outer layer of the retina.

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Palun, Lionel. "Etude prospective sur les dispositifs silicium à blocage de Coulomb dans une perspective d'application à la micro-électronique." Université Joseph Fourier (Grenoble), 2000. http://www.theses.fr/2000GRE10019.

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A court ou moyen terme (2002-2010) les projections de generations technologiques en micro-electronique prevoient une limitation physique et technologique des composants silicium. Les dispositifs a blocage de coulomb y sont souvent evoques comme une alternative ou un complement possible. Dans une perspective industrielle, de tels dispositifs doivent etre fabriques avec une technologie silicium et fonctionner a temperature ambiante. Ce travail de these se propose comme une contribution a la reflexion sur les debouches industriels possibles du blocage de coulomb. Le chapitre 1 presente un etat de l'art de deux familles de dispositifs silicium a blocage de coulomb : les transistors a un electron (single electron transistor) et les memoires a un electron. Le chapitre 2 est dedie a une etude sur le confinement des electrons dans un ilot nanometrique de silicium entoure de sio 2. Cette etude conduit a l'introduction de la notion de capacite quantique. Le chapitre 3 propose un rappel theorique sur le blocage de coulomb, dans lequel est integre la capacite quantique. Le passage tunnel entre deux ilots de silicium est discute a l'aide de la notion de resistance tunnel. Le chapitre 4 est consacre a une nouvelle architecture de cellule memoire silicium a blocage de coulomb : la cellule memoire a jonctions tunnel verticales. Son fonctionnement est decrit a l'aide du simulateur setmos. Ce simulateur a ete developpe au cours de la these et permet de simuler conjointement un set a ilots nanometriques de silicium et un transistor mos, en prenant en compte la capacite quantique des ilots. Le chapitre 5 decrit la fabrication d'un transistor a un electron realise sur des plaques soi (silicon on insulator) de 200 mm de diametre avec des outils de recherche et developpement de la micro-electronique. Bien que n'offrant pas de caracteristique claire de blocage de coulomb, la fabrication de ce dispositif a permis le demarrage d'une serie de projets technologiques au leti sur le theme de la nano-electronique.

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Brorson, Erik. "Classifying Hate Speech using Fine-tuned Language Models." Thesis, Uppsala universitet, Statistiska institutionen, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-352637.

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Given the explosion in the size of social media, the amount of hate speech is also growing. To efficiently combat this issue we need reliable and scalable machine learning models. Current solutions rely on crowdsourced datasets that are limited in size, or using training data from self-identified hateful communities, that lacks specificity. In this thesis we introduce a novel semi-supervised modelling strategy. It is first trained on the freely available data from the hateful communities and then fine-tuned to classify hateful tweets from crowdsourced annotated datasets. We show that our model reach state of the art performance with minimal hyper-parameter tuning.

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Fortea, Richard, and Nils Vennberg. "Ljudbilders Mättnad i Film : Hur tjocka och tunna ljudbilder byggs upp." Thesis, Blekinge Tekniska Högskola, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-20403.

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Detta kandidatarbete undersöker ljudbilder i film och vad som påverkar ljudbildens mättnad. Med stort fokus på Walter Murchs Dense Clarity, Clear Density (2005) bryter vi ner uppbyggnaden av en ljudbild för att få bättre förståelse kring detta. Med en egenframtagen analysmetod som fokuserar på filmers ljudbild analyserar vi scener ifrån flertalet filmer och tv-program, hittar mönster kring deras ljudläggning och hur det påverkar ljudbilden. Därefter bygger vi upp en lista med förhållningspunkter för olika typer av ljudbilder. Resultatet av undersökningen blir en förklaring av hur man uppnår olika former av ljudbilder i film och varför det blir så.

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Barnhart, Samuel. "Design and Development of a Coherent Detection Rayleigh Doppler Lidar System for Use as an Alternative Velocimetry Technique in Wind Tunnels." University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1595276402371536.

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Tomasoni, Angela Maria. "Modèles et méthodes d'évaluation et de gestion des risques appliqués aux systèmes de transport de marchandises dangereuses (TMD), reposant sur les nouvelles technologies de l'information et de la communication (NTIC)." Phd thesis, École Nationale Supérieure des Mines de Paris, 2010. http://pastel.archives-ouvertes.fr/pastel-00006223.

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Durant ma thèse de doctorat, j'ai développé plusieurs modèles et méthodes d'évaluation des risques dans les systèmes de transport de matières dangereuses. En raison de la multiplicité des approches d'évaluation de risque, tous les modèles décrits, définis et utilisés sont fondés sur la définition classique du risque technologique - liés à l'activité de l'homme - la catégorie des risques accidentels, - ou d'un accident - d'un véhicule transportant des matières dangereuses. Cette définition des risques est la même pour les conduites que pour le transport par route, mais différentes approches méthodologiques pour l'évaluation des risques de transport peuvent être abordées : Au chapitre n°2: une définition générale des marchandises dangereuses a été réalisé ainsi que différents types de matières dangereuses considérées. Ensuite, l'étude a été focalisé sur les hydrocarbures ainsi que sur les réglementations qui y sont liés. Dans le chapitre n°3, l'étude a porté sur la définition des risques dans le transport des matières dangereuses, respectivement, dans le cas des pipelines ainsi que pour le transport routier. Au cours du 4ème chapitre, une description complète de la méthodologie d'évaluation des risques de pipelines a été réalisé. Par la suite, au chapitre n°5, un modèle innovant et technologique a été utilisé afin de décrire un scénario d'accident du GPL par route et d'évaluer son impact sur la population concernée. Au chapitre n°6, j'aborde des modèles et des méthodes innovants pour l'évaluation des risques et le contrôle de la DGT par route. Cette méthodologie est basée sur une approche "Risk averse decision making" . Au chapitre n°7, une loi de contrôle optimale de la DGT a été développé et appliqué dans le cas d'une infrastructure critique, spécifiquement, dans le cas des tunnels. Enfin, le chapitre n°8 a pour objectif de résumer mon travail en termes de résultats obtenus au cours de ma thèse.

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Tunger, Antje [Verfasser], Marc [Akademischer Betreuer] [Gutachter] Schmitz, and Michael [Gutachter] Göttfert. "Generierung hoch-avider, WT1126-spezifischer CD8+ zytotoxischer T-Zell-Klone mit anti-leukämischer Aktivität mittels Streptamer-Technologie / Antje Tunger ; Gutachter: Marc Schmitz, Michael Göttfert ; Betreuer: Marc Schmitz." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://d-nb.info/1123932182/34.

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Soulier, Antoine. "Caractérisation du fonctionnement aérodynamique du e-Penon, capteur de décollement pour les pales d'éoliennes." Thesis, Ecole centrale de Nantes, 2020. http://www.theses.fr/2020ECDN0005.

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La complexité de l’écoulement amont sur les éoliennes peut être la cause de décollement et/ou de décrochage sur les pales d’éoliennes. Ces phénomènes sont à l’origine de variations des efforts aérodynamiques et provoquent ainsi un vieillissement accéléré des pales. Aujourd’hui il n’existe pas de capteur capable de détecter localement le décollement sur les pales d’éoliennes, utilisable sur les éoliennes en production. Le e-Penon a été développé pour pallier ce manque. L’objectif de cette thèse a été de caractériser l’impact de la présence du e-Penon sur l’aérodynamique de la pale et d’évaluer la performance du e-Penon, dans sa capacité à détecter l’apparition du décollement/décrochage et du réattachement de l’écoulement. Pour cela des mesures ont été réalisées dans deux souffleries. La soufflerie NSA du CSTB avec un profil 2D de pale de taille réaliste et un e-Penon à échelle 1 a été le siège d’essais avec des angles d’incidences fixes. La soufflerie aérodynamique du LHEEA, a été utilisée avec le même profil et un e-Penon, tous deux à échelle réduite avec des oscillations dynamiques de l’angle d’attaque. Il a été montré que seules les fluctuations locales des pressions pariétales et la signature spectrale du sillage proche du profil ont été modifiées par la présence du e-Penon, alors que les efforts aérodynamiques moyens globaux ne le sont pas significativement. En ce qui concerne la performance du e-Penon, il a été montré, avec les essais à l’échelle 1 qu’un e-Penon assez long et suffisamment souple est capable de détecter le décollement au bord de fuite et le décrochage, lorsque ce capteur est placé au bord de fuite. Enfin, la capacité de la languette d’un capteur e-Penon à detecter les instants de décrochage et de réattachement de l’écoulement a été démontrée pour le cas d’un profil à l’échelle réduite avec un angle d’incidence oscillant
Wind turbine inflow complexity can cause flow separation and stall on wind turbine blades. These phenomena are responsible of aerodynamic load fluctuations and thus a faster aging of the blades. Today there is no sensor able to detect locally the flow separation on blades of productive wind turbines. The e-Penon was developped to fill this lack. The aim of this thesis PHD was to characterise the impact of the presence of the e-Penon on blade aerodynamics and to assess the performance of the sensor about its capacity to measure flow separation, stall and reattachment. For this work, wind tunnel measurements were performed in two different wind tunnels. The NSA wind tunnel at CSTB with a 2D blade profile and a full scale e-Penon was used to perform measurments with static angles of attack. The aerodynamic wind tunnel of the LHEEA was used with the same 2D profile and a e-Penon, both at reduced scale, with angle of attack oscillations. It was shown that the presence of the e-Penon only impacts the wall pressure fluctuations around the sensor and the near wake spectral signature, while the global and mean aerodynamic forces are not significantly modified. It was also shown that an adequate flexibility and length of the e-Penon strip makes it able to detect both the flow separation at the trailing edge and the stall when positioned near the trailing edge. It was finally demonstrated that the strip of a downscaled e-Penon is able to detect stall, flow separation and reattachment instants when placed at the trailing edge of an oscillating airfoil at a reduced scale

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Bossuet, Alice. "Intégration sur silicium de solutions complètes de caractérisation en puissance de transistor HBT en technologie BiCMOS 55 nm à des fréquences au-delà de 130 GHz." Thesis, Lille 1, 2017. http://www.theses.fr/2017LIL10038/document.

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L’évolution des technologies silicium rend aujourd’hui possible le développement de nombreuses applications dans les domaines millimétriques tels que pour les systèmes de communication à très haut débit. Cette évolution se caractérise par une croissance des performances en fréquence des transistors disponibles dans ces technologies et nécessite la mise en place d’outils de mesure performants pour valider la modélisation et l’optimisation technologique de ces dispositifs. La caractérisation load-pull est une méthode incontournable pour modéliser le comportement en fort signal des transistors. En bande G [140-220 GHz], l’environnement de mesure classiquement disponible n’a plus les performances requises pour ce type de caractérisation compte tenu des pertes dans les accès au dispositif sous test. Ce travail de thèse a pour objectif de lever ce verrou en proposant de réaliser, en technologie BiCMOS 55 nm de STMicroelectronics, un banc load-pull entièrement intégré sur silicium afin d’être au plus près du dispositif à caractériser. Le mémoire est articulé autour de quatre chapitres. Le premier chapitre présente l’état de l’art de l’instrumentation actuellement disponible pour la caractérisation en puissance aux fréquences millimétriques et leurs limitations. Le second chapitre détaille la conception et la caractérisation des blocs constituant le banc intégré : le tuner et la source MMW de puissance. Le troisième chapitre décrit la réalisation et les performances du détecteur de puissance. Enfin, le quatrième chapitre présente le banc complet et son application à la caractérisation en bande G d’un dispositif bipolaire disponible dans la technologie BiCMOS 55 nm
The evolution of silicon technologies now makes possible the development of many applications in the millimeter areas such as high speed communication systems. The evolution of these silicon technologies is characterized by the increase of the transistor performances with the frequency that requires the development of efficient radiofrequency measurement tools for accurate modeling of active components or the optimization of integrated circuits. In this framework, the load-pull characterization is an essential method to model the behavior of transistors in nonlinear region. In the G Band, the classical measurement environment typically available has not the required performance for this kind of characterization due to the losses in the accesses to the device under test. The aim of this thesis is to lift this lock by offering, in the STMicroelectronics BiCMOS 55 nm technology, a fully integrated load-pull characterization bench on silicon in order to be as close as possible to the device to characterize. The thesis manuscript is divided into four chapters. The first chapter presents the state of the art of the currently available instrumentation for power characterization at millimeter wave frequencies band and their limitations, which leads to the G band characterization bench specifications. The second chapter details the design and characterization of the mains blocks constituting the integrated bench: the tuner and the mmw power source. The third chapter present the design and characterization of the power detector. Finally, the fourth chapter presents the complete bench and its application with the G band load-pull characterization of a transistor bipolar device

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Alami, Jones. "Plasma Characterization & Thin Film Growth and Analysis in Highly Ionized Magnetron Sputtering." Doctoral thesis, Linköping : Dept. of Physics and Measurement Technology, Univ, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-4147.

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Amestoy, Antoine. "Synthèse de nanohélices hybrides par auto-assemblage de type "bottom up" pour la fabrication de capteurs de déformation flexibles." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0041.

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Les capteurs de déformation flexibles et biocompatibles constitués d’assemblages de nanoparticules (NPs) sont prometteurs pour diverses applications futures, telles que la peau électronique, les écrans tactiles flexibles ou la robotique. Le principe de ces capteurs de déformations repose sur la conduction par effet tunnel entre les NPs qui varie de façon exponentielle lorsque que le film de NPs est déformé. Cependant, la sensibilité, la reproductibilité et la stabilité de ces capteurs sont affectées par les variations d'épaisseur, de morphologie et de densité des films lors de la fabrication ou au cours de leur utilisation. L’objectif de ces travaux est de développer des capteurs de déformations basés sur l'utilisation d’assemblages de nanohélices de silice recouvertes de NPs métalliques conductrices ou de NPs d’oxydes métalliques semi-conductrices pour surmonter ces aspects critiques. Dans la première partie, des NPs d’or sont synthétisées et fonctionnalisées avec différentes compositions de ligands isolants et sont ensuite greffées à la surface des nanohélices de façon covalente. Dans la seconde partie, des NPs semi-conductrices transparentes d’oxyde d’étain dopé à l’antimoine sont synthétisées, fonctionnalisées et assemblées à la surface des nanohélices par interactions électrostatiques ou covalentes. Enfin, les différents assemblages obtenus sont déposés par diélectrophorèse entre des électrodes interdigitées sur un substrat flexible. Les propriétés de flexibilité, de sensibilité et de stabilité des capteurs fabriqué sont ensuite caractérisées à l’aide de mesures électromécaniques couplées à des observations en microscopie électronique à balayage
Flexible and biocompatible strain sensors based on nanoparticle (NPs) assemblies show great potential for various future applications, such as electronic skin, flexible touch screens, and robotics. The high sensitivity of such strain sensing devices is due to the exponential dependence of the tunnel resistance on the distance between adjacent NPs, which is altered by the strain. However, the sensitivity, reproducibility and stability of these sensors are affected by variations in thickness, morphology and density of the films during manufacture or during their application. The objective of this work is to develop strain sensors based on assemblies of silica nanohelices covered with conductive metallic NPs or semiconducting metal oxide NPs to overcome these critical aspects. In the first part, gold NPs are synthesized and functionalized with different compositions of insulating ligands and are further grafted on the surface of the nanohelices with a covalent bond. In the second part, transparent semiconducting NPs of antimony-doped tin oxide are synthesized, functionalized and assembled on the surface of nanohelices by electrostatic or covalent interactions. Finally, the various assemblies obtained are deposited by dielectrophoresis between interdigitated electrodes on a flexible substrate. The flexibility, sensitivity and stability properties of the sensors are then characterized by electromechanical measurements coupled with scanning electron microscopy observations

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Emslie, Martin. "Station-nearness Principles in the Copenhagen Region and Scania, Integrating Urban Functions with Public Transit." Thesis, Blekinge Tekniska Högskola, Sektionen för teknokultur, humaniora och samhällsbyggnad, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-1264.

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Abstract Station-nearness principles as we will discuss in this paper, deals with the coordination of urban functions with the public transportation network. When we talk about functions, we mean residences, workplaces, commercial services, entertainment venues, places of culture, etc. These functions should be high density, there should be a mix of them and they should be pedestrian friendly in nature. Effective integration of functions around train stations brings many benefits and is one of the best means by which you can increase public transport use and increase the accessibility for people in a region. More and more, cities in North America, Europe and other places, are exploring the idea of how this concept can be applied. The Copenhagen region as we will discuss, has placed station-nearness principles at the forefront of their finger plan. Since the Copenhagen region has applied these principles, they have seen clear results with increased public transit ridership, as well on the overall, an increase in the standard of living. As many places are exploring the concept, not everyplace has been able to make the concept work. When we look at Scania, the concept is under utilized to a degree. There continues to be many populated and dense areas in Scania where the coordination of urban functions with public transit is lacking. The automobile is also gaining stronger competition over public transportation; this is a concern in terms of the sustainable future and quality of life for the region. It is not always the solution to simply expand the public transportation network, rather it can be significant to explore more upon the concept of station-nearness principles so that the existing public transit network can be made more effective. It is important to compare places, see in our case study how the concept has worked in the Copenhagen region and look into why the concept is lacking in Scania, as well, what can be done to implement it more in Scania. It is also important how the Öresund region as whole, can play a role with developing the concept, as well, how the concept can benefit the Öresund region vice versa.

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Karoumi, Raid. "Response of cable-stayed and suspension bridges to moving vehicles : Analysis methods and practical modeling techniques." Doctoral thesis, KTH, Byggkonstruktion, 1998. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2764.

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This thesis presents a state-of-the-art-review and twodifferent approaches for solving the moving load problem ofcable-stayed and suspension bridges. The first approach uses a simplified analysis method tostudy the dynamic response of simple cable-stayed bridgemodels. The bridge is idealized as a Bernoulli-Euler beam onelastic supports with varying support stiffness. To solve theequation of motion of the bridge, the finite difference methodand the mode superposition technique are used. The second approach is based on the nonlinear finite elementmethod and is used to study the response of more realisticcable-stayed and suspension bridge models considering exactcable behavior and nonlinear geometric effects. The cables aremodeled using a two-node catenary cable element derived using"exact" analytical expressions for the elastic catenary. Twomethods for evaluating the dynamic response are presented. Thefirst for evaluating the linear traffic load response using themode superposition technique and the deformed dead load tangentstiffness matrix, and the second for the nonlinear traffic loadresponse using the Newton-Newmark algorithm. The implemented programs have been verified by comparinganalysis results with those found in the literature and withresults obtained using a commercial finite element code.Several numerical examples are presented including one for theGreat Belt suspension bridge in Denmark. Parametric studieshave been conducted to investigate the effect of, among others,bridge damping, bridge-vehicle interaction, cables vibration,road surface roughness, vehicle speed, and tuned mass dampers.From the numerical study, it was concluded that road surfaceroughness has great influence on the dynamic response andshould always be considered. It was also found that utilizingthe dead load tangent stiffness matrix, linear dynamic trafficload analysis give sufficiently accurate results from theengineering point of view.
QC 20100511

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Bossens, Frédéric. "Amortissement actif des structures câblées: de la théorie à l'implémentation." Doctoral thesis, Universite Libre de Bruxelles, 2001. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211598.

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Cette thèse s'inscrit dans la continuation du travail de Younes Achkire, consacré au contrôle actif des ponts haubanés. Elle traite de l'implémentation d'un système de contrôle actif sur des maquettes de structures câblées. Deux types de structures sont étudiés expérimentalement: les ponts haubanés et les treillis spatiaux. Après une brève introduction sur l'usage du contrôle actif dans ces domaines, le chapitre 2 traite numériquement des mécanismes d'interaction entre le câble et la structure. Au chapitre 3, nous présentons la stratégie de contrôle que nous utilisons pour stabiliser une structure câblée: il s'agit d'un contrôle décentralisé, basé sur des paires capteur/actionneur colocalisées, placées au niveau des ancrages des câbles, chacune équipée d'un contrôleur Intégral Force Feedback. Nous présentons une théorie linéaire simplifiée permettant de dimensionner le système et de prévoir son efficacité. Elle est illustrée sur un exemple, et nous discutons de la validité de certaines hypothèses simplificatrices. Le chapitre 4 est consacré au contrôle actif des ponts haubanés. Nous y présentons 2 maquettes. La première, de petite taille (3m) représente un pylône de pont haubané en construction. Elle est équipée d'actionneurs piézoélectriques. La seconde, installée au Centre Commun de Recherche d'Ispra (Italie), mesure 30m de long, et est équipée d'actionneurs hydrauliques. Les expériences réalisées sur ces maquettes ont démontré l'efficacité du contrôle et la fiabilité de la théorie prédictive. Le contrôle du flottement des ponts est traité sur un exemple numérique. Le chapitre 5 relate nos expériences d'amortissement actif des treillis spatiaux. Deux structures ont été étudiées: une colonne en treillis équipée de 3 câbles actifs, et une structure triédrique suspendue à des cordons élastiques pour simuler l'absence de gravité, également munie de câbles actifs. Deux concepts d'actionneur piézoélectrique ont été testés. Nous avons ensuite examiné le problème de la saturation des actionneurs, et celui du contrôle actif des microvibrations (~10nm) d'une structure câblée. Le chapitre 6 conclut ce travail, en souligne les aspects originaux et donne quelques perspectives de développement.
Doctorat en sciences appliquées
info:eu-repo/semantics/nonPublished

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Dissertations / Theses on the topic 'Tunnel technology'

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