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When a tunnel is built in rock, a type of water is formed as a residual product. This tunnel wateris formed due to construction processes such as drilling requiring water and groundwater thatinfiltrates into the tunnel. The water can cause environmental damage if it is released directlyinto nature and needs to be treated. Usually, therefore, the water is purified regardingconcentrations of suspended matter, oil, metals, nitrogen and basic pH values. In this degree project water analysis data, after a local purification in the tunnel area, has beenobtained from 17 different tunnel projects and processed to look into the water quality in theseprojects. The parameters from the analysis data processed are the concentrations of nitrogen,arsenic, lead, cadmium, chromium, mercury, nickel, zinc, chloride, and suspended matter aswell as pH value and conductivity. The results show a large variation in the average valuesbetween the projects and also that a flocculation step in the purification lowers the averageconcentrations for most metals. An analysis of the suitability of using tunnel water for irrigation and fertilization purposes hasalso been carried out by examining the differences in the characteristics of tunnel watercompared to irrigation and fertilizer sources. The result shows that the average concentrationsof the metals chromium and nickel exceed the average concentrations found in groundwaterand surface water in several projects. This means that the tunnel water with respect to thesetwo metals differs from natural sources of irrigation water. According to FAO's guidelines forirrigation water, the average chloride content and average conductivity of the tunnel water isalso elevated and means that the use of the water for irrigation may need to be partly limited.However, this influence needs to be investigated more for Swedish conditions / När en tunnel byggs i berg uppkommer länshållningsvatten, vilket är en restprodukt som måsteomhändertas. Länshållningsvattnet bildas med anledning av att processer som exempelvisborrning kräver vatten samt att grundvatten tränger in i tunneln. Länshållningsvattnet behöverrenas då det kan påverka miljön negativt om det släpps ut direkt i naturen. Vanligtvis renasdärför vattnet med avseende på suspenderat material, olja, metallhalter, basiska pH-värden ochkvävehalter. I arbetet har vattenanalysdata, efter en lokal rening i tunnelområdet, inhämtats från 17 olikatunnelprojekt och bearbetats för att utreda vattnets innehåll i dessa projekt. De parametrarfrån analysdatan som behandlats är koncentrationerna av kväve, arsenik, bly, kadmium, krom,kvicksilver, nickel, zink, klorid och suspenderat material samt pH-värde och konduktivitet. Iresultatet ses en stor variation i medelvärdena mellan projekten och även att ett flockningssteg ireningen sänker medelhalterna för de flesta metaller. En utredning av lämpligheten att använda länshållningsvatten i bevattnings- och gödslingssyftehar också utförts. Detta gjordes genom att klargöra vilka skillnader som finns i halterna avmetaller, kväve och klorid samt i pH-värdet och konduktiviteten hos länshållningsvatten, jämförtmed befintliga bevattnings- och gödselkällor. Resultatet visar att medelhalterna av metallernakrom och nickel överskrider medelhalterna som finns i grundvatten och ytvatten i flera projekt.Detta innebär att länshållningsvattnet med avseende på dessa två metaller skiljer sig från naturligakällor av bevattningsvatten. Enligt FAO:s riktvärden för bevattningsvatten är länshållningsvattnetsmedelkloridhalt och medelkonduktivitet dessutom förhöjd och innebär att användningen avvattnet till bevattning kan behöva begränsas. Denna påverkan behöver dock utredas mer försvenska förhållanden.

<p>A model to predict carpal tunnel syndrome (CTS) risk would improve ergonomic assessments and help reduce the incidence of occupational CTS and its associated costs. Research spanning over sixty years has shown that deviated wrist, forearm, and hand posture has on the hydrostatic pressure within the carpal tunnel (also known as carpal tunnel pressure, CTP). Elevated CTP is a mechanism of the development, or aggravation of CTS symptoms. The purpose of this thesis was to develop a model to predict CTS risk, based on CTP, and incorporate the model into an ergonomic tool for use by ergonomists. An extensive literature review identified additional studies that investigated the effects of pronation/supination, finger posture, and fingertip loading on CTP. The effect of wrist, forearm, and hand posture was then incorporated into the model via a series of regression equations developed for each plane of movement. The effect of fingertip loading (independent to the posture effects) was included using a multiplier based on the hand posture and load magnitude. To provide a user-friendly tool for ergonomists, a graphical-user-interface was developed to predict CTS risk based on the developed model. Input variables were wrist, hand, and forearm posture, and fingertip loading. CTP program estimated CTP, and compared the predicted pressure to a known threshold beyond which median nerve function has been shown to degrade. The tool was then evaluated by comparing the output of the tool (CTS risk) to the incidence of CTS in a large automotive manufacturing environment. There was no significant difference between the two groups (workers completing jobs with an incidence of CTS and workers completing jobs with no incidence of CTS). The tool marks an important first step v towards providing ergonomists with a much-needed tool to predict CTS risk based on posture, frequency, and fingertip force.</p> / Master of Science (MSc)

<p dir="ltr">Force and moment measurements are valuable tools for evaluating designs in a wind tunnel environment. In fact, this type of research has been conducted ever since the earliest wind tunnels were in use. Load measurement techniques are complicated by hypersonic wind tunnel designs, which often have much shorter test times due to the immense stagnation pressures that are used. Previous research had been conducted once before in the Boeing/AFOSR Mach 6 Quiet Tunnel (BAM6QT) at Purdue University using a six-component moment balance. This initial testing utilized a balance with maximum load limits which far exceeded the loads experienced within the BAM6QT. Because of this, much of the data collected was imprecise. </p><p dir="ltr">Testing was conducted in the BAM6QT using three different balances - a five-component foil, five-component semiconductor, and six-component semiconductor balance. Data were taken for a variety of geometry configurations over a range of total pressures. All data were taken at 0 degree angle of attack. The two geometries used most commonly were the 1 inch diameter blunt nose-tip, 7 degree half-angle, 1.75 inch base diameter cone, with either a 20 degree or 30 degree curved ramp. An additional sharp nose-tip configuration was also used. Results for multiple load components were calculated during each run and compared between each balance type. Results were compared to the surface panel method results of CBAERO, which uses either modified Newtonian theory or the tangent cone method to compute loads. </p><p dir="ltr">Results between each balance type were similar and generally in good agreement. The semiconductor balance designs showed considerably less noise than the foil design. Results of CBAERO matched well with the balance data, with a baseline comparison of the plain blunt cone showing a maximum difference of 12% for the modified Newtonian theory. The more complicated ramp geometries, which exhibited regions of flow detachment, agreed surprisingly well with CBAERO results, despite the more complicated flow phenomena, which was unexpected. The best agreement was generally seen in the cases where the large 30 degree ramp was used, while the sharp nose-tip configuration produced the worst agreement. Overall, CBAERO proved valuable as an approximate method for determining the general magnitude of loads. The sting, used to mount the model in the wind tunnel, was found to drive the oscillation frequency of the model-sting system. The longer sting and less stiff balance used on the six-component system likely contributed to lower oscillation frequencies which affected the results for the pitching moment and normal force. The relationship between startup and running loads was also investigated and a startup-to-running load ratio of 5 to 20 was determined, depending on the load component and geometry.</p>

Wind tunnels are important tools used in physics and engineering, with a wide range of usability and applications in industrial, research, and educational settings. A wind tunnel holds an object steady while generating airflow over it, often to study the interaction between the object and the airflow. The design of wind tunnels can be very costly, extensive, and difficult to implement. This paper analyzes literature on wind tunnels to compile a method for designing a portable wind tunnel suitable for educational and demonstrative purposes. The method includes design guidelines for each component, including the test section, contraction, settling chamber, honeycomb, diffuser, and fan section. A blueprint for a wind tunnel with specified dimensions is presented. The blueprint is designed to fit a Boeing 747-200 model, scaled at 1:390, and therefore have a 40 cm long test section with a 20x20 cm square cross-section. The designed wind tunnel achieves a velocity of 5 m/s in the test section. Emphasizing portability, simplicity, and functionality, this wind tunnel design enhances educational experiences, making complex fluid dynamics concepts accessible and engaging for students.

Wind tunnels are important tools used in physics and engineering, with a wide range of usability and applications in industrial, research, and educational settings. A wind tunnel holds an object steady while generating airflow over it, often to study the interaction between the object and the airflow. The design of wind tunnels can be very costly, extensive, and difficult to implement. This paper analyzes literature on wind tunnels to compile a method for designing a portable wind tunnel suitable for educational and demonstrative purposes. The method includes design guidelines for each component, including the test section, contraction, settling chamber, honeycomb, diffuser, and fan section. A blueprint for a wind tunnel with specified dimensions is presented. The blueprint is designed to fit a Boeing 747-200 model, scaled at 1:390, and therefore have a 40 cm long test section with a 20x20 cm square cross-section. The designed wind tunnel achieves a velocity of 5 m/s in the test section. Emphasizing portability, simplicity, and functionality, this wind tunnel design enhances educational experiences, making complex fluid dynamics concepts accessible and engaging for students.

The Tunnel Field Effect Transistor (TFET) with sub-60mV/decade Sub-threshold slope and extremely high ION/IOFF ratio has attracted enough attention for low standby power (LSTP) applications where the battery life is very important. So far research in this area has been limited to numerical simulation and experimental analysis. It is however extremely necessary to develop compact models for TFET in order to use them in nano-scale integrated circuit design and simulation. In this work, for the first time, we develop analytical Sub-threshold slope model for n-channel double gate TFET (nDGTFET). Unlike conventional FETs, current in TFET is mainly controlled by the band-to-band tunneling mechanism at source/channel interface. As the total drain current is proportional to band-to-band generation rate, the main challenge in the present work is to find an explicit relationship between average electric field over the tunneling path and the applied gate voltage under nonlocal tunneling condition. Two dimensional Poisson’s equation (with Laplace approximation)is first solved in a rectangular coordinate system in order to obtain analytical expression for electron energy distribution over the channel region.Kane’s Model[J. Phy. Chem.Solids 12(181)1959]for band-to-band tunneling along with some analytical approximation techniques are then used to derive the expression for the Sub-threshold slope under nonlocal tunneling conditions. This Sub-threshold slope model is verified against professional numerical device simulator (MEDICI) for different device geometries. Being an asymmetric device, TFET fabrication suffers from source misalignment with gate. As the doping in source and drain-gate are different, conventional-FET-like self-aligned gate stack formation is not possible for TFET. Such misalignment, at source side, seriously degrades the performance of TFETs. To overcome this problem, in this work we explore the possibility of using “gate replacement” technique for TFET fabrication. We first develop process flow for single gate bulk nTFET, and then we extend it to n-channel double gate TFET (nDGTFET) using modified FinFET process. Good alignments between source and gate are observed with TCAD-simulations in both the cases.

Les modèles théoriques qui prônent l’existence d’un filtrage en symétrie dans les électrodes ferromagnétiques n’ont jamais souffert d’autre justification que leur potentiel à éclairer les résultats expérimentaux. En la matière, les jonctions tunnel magnétiques Fe/MgO/Fe(001) apparaissent être un outil approprié pour confronter expérience et théorie de par leur haute qualité cristalline, cette dernière étant essentielle pour se rapprocher au plus près des considérations théoriques. Les premières mesures de bruit basse fréquence réalisées sur ce système en démontrent la qualité remarquable, paramètres primordiaux au bon déroulement des mécanismes de transport tunnel. L’étude de la dynamique du courant a permis de montrer l’existence d’un mode de transport tunnel direct d’une électrode à l’autre et d’invalider un mode de transport séquentiel via des défauts dans la barrière. L’intégration de films minces de Cr(001) dans ce système idéal a permis de valider de façon non ambigüe l’existence effective du filtrage en symétrie suite à l’apparition d’états de puits quantiques pour une seule symétrie électronique dans des jonctions Fe/Cr/Fe/MgO/Fe. Ce résultat phare met aussi en évidence un mode de transport tunnel cohérent et balistique. La validation de ces concepts autorise l’étude de l’injection de spin dépendant des symétries dans des matériaux plus complexes, comme des films minces de Fe3O4(001). Ces derniers ont fait l’objet d’une étude structurale approfondie et ont amené à des résultats de magnéto-transport encourageants suite à leur intégration dans des dispositifs tunnel à base de MgO(001). / The symmetry-filtering into the ferromagnets as predicted by the theoreticians has never suffered of any other justification than its ability to shed the light on the experimental observations. Fe/MgO/Fe(001) junctions are then an appropriate tool to test its validity thanks to their high crystallinity. The first performed low frequency noise measurements have proved the well-suited quality of this kind of junctions and the study of the current’s dynamic through the system, its pure direct tunneling. By using Cr(001) thin films, the symmetry-filtering has been unambiguously highlighted with the occurrence of quantum-well states only for one specific electronic symmetry in Fe/Cr/Fe/MgO/Fe(001). Thus, the validity of the theoretical concepts allows investigating the symmetry-dependent spin-injection into more complex systems such as Fe3O4(001) thin films which have revealed theirselves as promising to integrate into MgO(001)-based tunnel devices.

Depuis l'avènement des nanotechnologies, une grande quantité de matériaux sont façonnés à l'échelle du nanomètre par des techniques diverses et l'intégration de ces nanostructures demande une caractérisation de leur structure électronique. La microscopie à effet tunnel est adaptée à ces études car elle permet l'adressage de nanostructures uniques pour mesurer leur structure électronique. <br>Nous rapportons ici l'étude du transport électronique dans deux types de nanostructures: des nanotubes de carbone simple paroi déposés sur une surface d'or et des atomes uniques de silicium sur un substrat de silicium. <br>Dans la première étude, le couplage faible entre un nanotube et le substrat permet d'accéder à la densité d'états unidimensionnelle des nanotubes et autorise la formation de défauts ponctuels, ayant des états localisés dans la bande interdite des nanotubes. Cette modification, réversible, de la structure atomique des nanotubes de carbone amène des opportunités concernant la modification controlée et à volonté de leurs propriétés électroniques. <br>La deuxième étude vise à caractériser la dynamique des porteurs dans une liaison pendante de silicium énergétiquement isolée de tout autre état électronique sur une surface Si(111). L'analyse du transport révèle un courant inélastique mettant en oeuvre la recombinaison non radiative des électrons de la pointe avec des trous capturés par l'état de la liaison pendante, grâce à l'émission de vibrations. La spectroscopie à effet tunnel montre de plus que l'on peut caractériser l'efficacité de capture d'un état quantique unique, en connaissant son niveau d'énergie, sa fonction d'onde, sa section de capture et le couplage électron-phonon.

Les travaux présentés dans cette thèse s'inscrivent dans le cadre général de la description de l'effet tunnel dans la limite semiclassique $\hbar \rightarrow 0$. Nous présentons une nouvelle méthode de calcul direct de la largeur des doublets tunnel. L'expression obtenue est basée sur l'utilisation de traces d'opérateurs quantiques, dont l'opérateur d'évolution $\hat{U}(T)$ prolongé analytiquement à l'aide d'un temps complexe $T$. L'étape suivante consiste en un développement semiclassique de ces traces. Nous nous plaçons dans le cadre des systèmes intégrables unidimensionnels afin d'insister sur l'importance d'un temps complexe et on montre que le choix d'un chemin du temps $[t]$ adapté, lors du calcul semiclassique des traces, fournit un critère de sélection efficace des trajectoires complexes dominantes. Nous verrons que cette approche retrouve la technique des instantons dans la limite d'un temps purement imaginaire et qu'elle permet d'inclure les descriptions, inaccessibles par une rotation de $\textsc{Wick}$ complète, de l'effet tunnel dynamique et résonant. Nous montrons également comment adapter cette méthode au taux de transmission tunnel d'un état localisé dans un minimum local vers un continuum d'états. Enfin, nous proposerons, en guise de perspectives, d'étudier l'effet tunnel résonant à partir de modèles intégrables présentant des îlots stables entourés de chaînes de tores pour lesquels nous tenterons d'adapter la théorie de l'effet tunnel assisté par les résonances.