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[pt] O processo de revestimento por extrusão é um método muito utilizado na manufatura de diversos produtos. Ele pertence à uma classe de processos de revestimento chamada revestimento com vazão pré-fixada: para operações em regime permanente, a espessura da camada de líquido revestida é definida pela vazão na entrada do equipamento e pela velocidade do substrato. Para diversas aplicações, o líquido de revestimento é uma suspensão de partículas. A abordagem comumente usada é analisar o escoamento como se o fluido fosse Newtoniano, onde sua viscosidade é avaliada pela concentração média de partículas. Porém, dados experimentais mostram que a distribuição de partículas não é uniforme em escoamentos com cisalhamento. Além disso, a distribuição de partículas no filme após o processo de revestimento afetará a estrutura final do filme e, consequentemente, a qualidade final do produto. Portanto, é importante entender os fundamentos do processo de revestimento com suspensão de partículas para melhor descrever este processo e prever comportamentos desse escoamento. O objetivo do presente trabalho é estudar diferentes mecanismos de migração de partículas em suspensão que podem afetar a distribuição de partículas no filme revestido; como mecanismos de difusão e sedimentação. O modelo apresentado leva em consideração a dependência da viscosidade pela concentração local de partículas e o efeito de Marangoni. Dois modelos diferentes foram usados para estudar o escoamento de Marangoni. No primeiro, o transporte de partículas entre a superfície e o escoamento é considerado muito mais rápido que a difusão no escoamento de tal forma que o fluxo líquido é zero e a concentração de partículas na região do escoamento próxima à superfície. No segundo, um modelo mais completo, os efeitos de adsorção e dessorção de partículas pela interface é considerado. O sistema final de equações e não-linear e, com as condições de contorno apropriadas, é resolvido pelo método de Galerkin em elementos finitos e pelo método de Newton. O escoamento é bi-dimensional e, portanto, elementos bi-dimensionais são utilizados para descrever o domínio do problema. Entretanto, para avaliar a concentração ao longo da superfície, foi necessário criar um elemento uni-dimensional. O acoplamento entre estas duas classes de elementos também é discutido. Os resultados mostram que a distribuição de partículas do filme revestido é uma forte função da espessura do filme e das propriedades da suspensão, como a densidade das partículas e coeficientes de difusão. O escoamento de Marangoni pode afetar o padrão de recirculação e a distribuição de concentração de partículas. Além disso, os resultados mostram que a adsorção e dessorção de partículas na interface afetam fortemente a distribuição de partículas. / [en] Slot coating is a common method in the manufacturing of a wide variety of products. It belongs to a class of coating method known as premetered coating: in a steady state operation, the thickness of the coated liquid layer is set by the flow rate fed to the die and the speed of the substrate moving past, and is independent of other variables of the process. For many applications, the coating liquid is a particle suspension. The commom simplified approach is to study the flow as Newtonian and evaluate its viscosity based on the average particle concentration. However, experimental data shows that particle distribution is in fact non-uniform in shear flows. Moreover, particle distribution along the film thickness during the coating process will affect the final fim structure and consequently product performance. Hence, it is important to understand the fundamentals of coating process with particle suspension to better describe and predict the behavior of the flow and the particle distribution in the coated layer. The goal of the present work is to study different particle migration mechanisms in a suspension that may affect particle distribution in the coated film; such as diffusive mechanisms and sedimentation. The model presented takes into account the viscosity dependency and local particle concentration and surface-active particles, i.e. Marangoni effect. Two different approaches were used to study Marangoni flow. First, the bulk-interface transport is considered much faster than bulk diffusion such that the net flux is zero and surface concentration is equal bulk concentration. The second, more complete model, considers adsorption and desorption fluxes from the interface. The non-linear system of equations, with appropriate boundary conditions, is solved by Galerkin Finite Element Method and Newton s Method. The flow is two-dimensional and therefore two-dimensional elements are used to describe flow domain. Nonetheless, in order to evaluate particle concentration along the interface a one-dimensional element was created. The coupling between those two classes of elements of discussed. The results show that the particle distribution on the coated layer is a strong function of the film thickness and suspension properties, such as particle density and diffusion coefficients. The Marangoni flow associated with surface tension gradient due to particle concentration variation along the interface can change the recirculation pattern and particle concentration distribution. Furthermore, the results show that particle adsorption and desorption from interface have a strong effect on the particle distribution.

Nya casinon dyker upp allt oftare och spelberoende är ett återkommande ämne i nyheterna. Trots alla nya onlinecasinon finns det inga studier idag som undersöker hur den visuella aspekten av dessa onlinespel påverkar spelarna. Denna studie undersöker hur visuell återkoppling påverkar individernas spelande och risktagande när de spelar på onlinecasinon. För att studera dessa effekter genomfördes en studie på 45 studenter som delades in i två grupper. Båda grupperna blev ombedda att spela en prototyp av en enarmad bandit skapad för denna studie som heter "Casino Slotmachine". En grupp såg en vanlig grå pop-up ruta med resultat, medan den andra gruppen utsattes för animeringar i form av fallande konfetti när de vann och en mer estetiskt tilltalande popup-box i en ljusgul ton med resultat. Under spelet registrerades deltagarnas satsningar per runda, tid per runda samt antalet klick per runda. Varje deltagare spelade 20 rundor av spelet. Efter spelet svarade deltagarna på en enkät om deras spelupplevelse. Resultaten visar att deltagarna som fick visuell återkoppling tog större risker under sessionen än gruppen som inte fick visuell återkoppling. Visuell återkoppling kan därför vara en underliggande faktor till varför vissa spelare i onlinecasinon tar större risker idag. Undersökningen visar också på att de som fick visuell återkoppling blev mindre stressade av spelet än de som inte gjorde det. Både män och kvinnor påverkades på samma sätt av den visuella återkopplingen. / New casinos appear online constantly, and gambling addiction is a recurring subject in the news. Despite all the new online casinos, there are no studies today that investigate how the visual aspect of these online games affects the players. This study examines how visual feedback affects individuals' gambling and risk-taking when gambling on online casinos. To study these effects, a study was conducted on 45 students who were divided into two groups. Both groups were asked to play a prototype of a slot machine created for this study called "Casino Slotmachine". One group saw a regular gray pop-up box displaying net profit, while the other group was exposed to animations in the form of falling confetti when winning, and a more aesthetically pleasing pop-up box in a light yellow tone displaying net profit. During the game, the participants' bet per round, time per round and the amount of clicks per round was recorded. Each participant played 20 rounds of the game. After playing, the participants responded to a survey about their gaming experience. The results show that the participants who received visual feedback took more risks during the session than the group that did not receive visual feedback. Visual feedback can therefore be an underlying factor to why some players in online casinos are taking greater risks today. The survey also shows that those who received visual feedback became less stressed by the game than those who did not. Both men and women were similarly affected by the visual feedback.

In the past centuries, grouting has been one of the most common techniques in geotechnical engineering to strengthen and seal underground structures. Concerning increasing demands for tightness and cost efficiency, cement-based grout has been one the most frequent used materials. One of the first grouting operations is the work done by Charles Bérigny in France back in 1802 in order to repair a sluice by stabilizing the ground with liquid grout. Several studies have been then conducted in grouting, which have contributed into successful improvement of the grouting operations. The investigations have also extended the understanding of the factors such as choice of materials, choice of equipment, and the applied pressure type and magnitude, etc. that influencing the grout spread in rock fracture systems.   Among the factors, the applied pressure is one of the most significant ones influencing the spread of grout during grouting operations. Grouting at static pressure conditions is the most common method used in field, where in practice the injected grout can only penetrate into the rock fractures wider than 100 µm.   Recent investigations conducted on application of static and dynamic pressure conditions, using Short Slot and Varying Aperture Long Slot (VALS) in the lab have yielded an overall improvement of the grout spread under dynamic pressure conditions rather than the conventional static pressure conditions. However, the efforts conducted are just a beginning, especially in very fine micro factures smaller than 70 µm    The main objective of this investigation was therefore to improve the spread of grout by dynamic grouting into fractures smaller than 70 µm effectively, which could not be done with grouting at static pressure conditions.  Furthermore, the aim was to investigate filtration and erosion phenomena/ tendency of grout flow during static and dynamic pressure application using Varying Aperture Long Slot (VALS) in the lab. The durations of peak and rest periods used in the experiments were 2s/2s and 1s/5.5s, which were equivalent to 0.25 Hz and 0.15 Hz, respectively. The results of dynamic grouting showed up to 10 times improvement in the volume of passed grout through fracture apertures smaller than 70 µm. / Injektering är en av de vanligaste metoderna som använts för att förstärka och täta geotekniska konstruktioner. När det gäller ökande krav på täthet och kostnadseffektivitet har cementbaserade bruk varit ett populärt förbrukningsmaterial. Injektering användes förmodligen först av Charles Bérigny i en slussreparation i Frankrike under 1802 där marken stabiliserades med hjälp av flytande injekteringsmaterial. Flera studier har sedan dess utförts inom injekteringsteknik, vilket har bidragit till en framgångsrik förbättring av injekteringsoperationer. Dessa undersökningar har också utvidgat förståelsen av faktorer såsom materialegenskaper, val av utrustning, provprestanda, trycktyp och storhet som i sin tur påverkar brukets spridningsförmåga i bergets spricksystem.   Forskningen inom bergtätning fokuserar bland annat på att utveckla tillämpningen av statisk och dynamisk tryck vid injektering. Tillämpning av statiskt tryck är den vanligaste metoden för injektering ute i arbetsfält, där den injicerade bruket i praktiken endast kan tränga in i bergssprickor som är större än 100 μm.   De senaste undersökningarna med hjälp av Short Slot och Varying Aperture Long Slot (VALS) har visat en övergripande förbättring av inträngningen under dynamisk injektering jämfört med de konventionella statiska. Detta är bara en början och metoden behöver utvecklas mer, särskild för att åstadkomma bruksspridningen i mycket finare mikrosprickor, exempelvis sprickor mindre än 70 µm.   Syftet med detta arbete var att utveckla injekteringsmetoden där bruket kan tränga  i berg med sprickor mindre än 70 µm. Resultaten på de dynamiska tryckförhållanden visade att injekteringsbruket trängde bättre  i de smala sprickor  jämfört med de statiska tryckförhållanden. Upp till 10 gånger mer mängd av injekteringsbruk passerade sprickor med storlek mindre än 70 µm i VALS. Vidare har inloppsflödet och filtrerings- och erosionsfenomenen studerats med hjälp av laboratorieinstrumentet VALS. Varaktigheten av peak- och restperioder som användes i experimenten var 2s/2s och 1s 5.5s, vilka var ekvivalenta med 0.25 Hz respektive 0.15 Hz.

The main goal of the grouting is to seal the fractures in the rock mass,improve the strength properties of the rock mass and decrease deformability. However,the overuse of the grouting should be avoided due mainly to economic reasons,optimizing the project time and sometimes severe environmental issues.Insufficient grout spread can cause worse sealing results and decreasedurability. To control the process of grouting and predict the penetrationlength an analytical solution called Real Time Grouting Control theory (RTGC) hasbeen developed. This thesis aimed to evaluate RTGC theory on the equipmentrepresenting a one-dimensional model of a fracture called Varying Aperture LongSlot - VALS. The evaluation was based on a comparison between the calculated(predicted) penetration length according to RTGC theory and the realpenetration obtained in the experiments. Results of the tests show that the RTGCtheory is a good tool to predict the penetration length of the grout at thejoints with apertures close to the hydraulic apertures. At the apertures,significantly less than the hydraulic aperture, the results of the test andRTGC theory differ a lot.

The infrared and millimeter-wave portions of the spectrum both have their advantages for development of imaging systems. Because of the difference in wavelengths, infrared imagers offer inherently high resolution, while millimeter-wave systems have better penetration through atmospheric aerosols such as fog and smoke. Shared-aperture imaging systems employing a common focal-plane array that responds to both wavebands are desirable from the viewpoint of overall size and weight. We have developed antenna-coupled sensors that respond simultaneously at 30 THz and at 94 GHz, utilizing electron-beam lithography. Slot-antenna designs were found to be particularly suitable for coupling radiation into metal-oxide-metal (MOM) tunnel diodes at both frequencies. The MOM diodes are fabricated in a layered structure of Ni-NiO-Ni, and act as rectifying contacts. With contact areas as low as 120 nm × 120 nm, these diodes have time constants commensurate with rectification at frequencies across the desired millimeter-wave and infrared bands. One challenge in the development of true focal-plane array imagers across this factor-of-300 bandwidth is that the optimum spatial sampling interval on the focal plane is different in both bands. We have demonstrated a focal plane with interleaved infrared and millimeter-wave sensors by fabricating infrared antennas in the ground plane of the millimeter-wave antenna. Measured performance data in both bands are presented for individual antenna-coupled sensors as well as for devices in the dual-band focal-plane-array format.

Improving the predictability of airline schedules in the National Airspace System (NAS) has been a constant endeavor, particularly as system delays grow with ever-increasing demand. Airline schedules need to be resistant to perturbations in the system including Ground Delay Programs (GDPs) and inclement weather. The strategic search heuristic proposed in this dissertation significantly improves airline schedule reliability by assigning airport departure and arrival slots to each flight in the schedule across a network of airports. This is performed using a multi-objective optimization approach that is primarily based on historical flight and taxi times but also includes certain airline, airport, and FAA priorities. The intent of this algorithm is to produce a more reliable, robust schedule that operates in today's environment as well as tomorrow's 4-Dimensional Trajectory Controlled system as described the FAA's Next Generation ATM system (NextGen). This novel airline schedule optimization approach is implemented using a multi-objective evolutionary algorithm which is capable of incorporating limited airport capacities. The core of the fitness function is an extensive database of historic operating times for flight and ground operations collected over a two year period based on ASDI and BTS data. Empirical distributions based on this data reflect the probability that flights encounter various flight and taxi times. The fitness function also adds the ability to define priorities for certain flights based on aircraft size, flight time, and airline usage. The algorithm is applied to airline schedules for two primary US airports: Chicago O'Hare and Atlanta Hartsfield-Jackson. The effects of this multi-objective schedule optimization are evaluated in a variety of scenarios including periods of high, medium, and low demand. The schedules generated by the optimization algorithm were evaluated using a simple queuing simulation model implemented in AnyLogic. The scenarios were simulated in AnyLogic using two basic setups: (1) using modes of flight and taxi times that reflect highly predictable 4-Dimensional Trajectory Control operations and (2) using full distributions of flight and taxi times reflecting current day operations. The simulation analysis showed significant improvements in reliability as measured by the mean square difference (MSD) of filed versus simulated flight arrival and departure times. Arrivals showed the most consistent improvements of up to 80% in on-time performance (OTP). Departures showed reduced overall improvements, particularly when the optimization was performed without the consideration of airport capacity. The 4-Dimensional Trajectory Control environment more than doubled the on-time performance of departures over the current day, more chaotic scenarios. This research shows that airline schedule reliability can be significantly improved over a network of airports using historical flight and taxi time data. It also provides for a mechanism to prioritize flights based on various airline, airport, and ATC goals. The algorithm is shown to work in today's environment as well as tomorrow's NextGen 4-Dimensional Trajectory Control setup.

In a bus chassis, welded connections are often preferred to other fastening techniques due to low cost and broad competence among suppliers but are usually the weakest parts due to fatigue life. Evaluation of welds is often costly in time and competence. Long iteration times are often leaving welded designs unoptimized and poorly understood by designers and engineers. The goal of this thesis is to gather knowledge about a plug-welded bracket commonly found welded to beams in bus chassis and body, aiding the design and dimensioning of such brackets. A factorial design study was performed using FEM analysis with the “Effective notch method,” revealing the effects of seven different design parameters on the stresses in the weld. A theory to analytically calculate the profile of the bracket is presented. The theory is taking the beam’s second moment of area and the bending moment into consideration, essentially tuning the bracket’s stiffness to the beam and the load situation. An improved bracket is presented, analyzed, and compared to the design study. The results show how stresses in the weld are affected by the stiffness of the bend in the bracket, the location of bolts (or other fastening technique) and the plug weld dimensions. When the weld is made to run longer along the beam, the importance of adjusting the stiffness in the bracket increases in order to balance the load throughout the whole weld. / Svetsade fästelement är ofta att föredra i ett busschassi över andra tekniker av kostnadsskäl och att en bred kompetens finns inom svets hos många underleverantörer. Men på grund av utmattning är ofta svetsade infästningar den svagaste punkten i ett chassi. Utvärdering av svetsar är kostsamt i tid och kompetens. Långa iterationstider i svetsutvärderingar lämnar ofta svetsen ooptimerad och undermåligt förstådd av designers och ingenjörer. Målet med detta arbete är att samla kunskap runt ett pluggsvetsat fästelement som ofta förekommer i busschassier och busskarosser, för att underlätta design och dimensionering av dessa fästelement. En faktoriell designstudie var utförd med FEM analys enligt ”Effective Notch” metoden för att undersöka effekten från sju olika designparametrar på spänningskoncentrationerna i svetsen. En teori för att analytiskt beräkna profilen på fästelementet presenteras. Teorin tar balkens böjtröghetsmoment och böjmoment med i beräkningen för att optimera fästelementets styvhet till balken och lastsituationen. Ett förbättrat fästelement är presenterat, analyserat och jämförd med designstudien. Resultaten visar hur spänningarna i svetsen påverkas av styvheten i den böjda delen av fästelementet, placeringen av bultar (eller annan infästningsteknik) och dimensioner på ”svetspluggen.” När svetsen är går längre längs med balken blir fästelementets styvhet allt viktigare för att kunna balansera lasten igenom det svetsade området.

No / To mitigate potential interferences with coexisting wireless systems operating over 3.3-3.6 GHz, 5.15-5.35 GHz, or 5.725-5.825 GHz bands, four novel band-notched antennas suitable for ultra-wideband (UWB) applications are proposed. These include UWB antennas with a single wide notched band, a single narrow notched band, dual notched bands, and triple notched bands. Each antenna comprises a half-circle shaped patch with an open rectangular slot and a half-circle shaped ground plane. Good band-notched performance is achieved by using high permittivity and low dielectric loss substrate, and inserting quarter-wavelength horizontal/vertical stubs or alternatively embedding quarter-wavelength open-ended slots within the feed line. The results of both simulation and measurement confirm that the gain suppression of the single and multiple band-notched antennas in each desired notched band are over 15 dB and 10 dB, respectively. The radiation pattern of the proposed triple band-notched design is relatively stable across the operating frequency band.

No / A compact-size asymmetrical linearly tapered slot antenna required for portable ultra-wideband (UWB) imaging systems is presented. The total antenna size is reduced compared with the conventional linearly tapered slot antenna by using a triangular slot on the left-hand side of the tapered-shaped radiator, whereas introducing a corrugated pattern of cuts on the right side. The antenna operates over a wide bandwidth extending from 3.1 to 10.6 GHz with a maximum gain of 8.5 dBi. Stable radiation patterns are observed across the operational bandwidth, with cross-polarization levels below 20 dB. The realized antenna structure occupies a volume of 35 x 36 x 0.8 mm3, and possesses the essential time domain fidelity needed for UWB imaging applications. (c) 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.