Magister Philosophiae - MPhil / The fascinating optical properties of metallic nanostructures, dominated by collective oscillations of free electrons known as plasmons, open new opportunities for the development of devices fabrication based on noble metal nanoparticle composite materials. This thesis demonstrates a low-cost and versatile technique to produce stimuli-responsive ultrafast plasmonic nanostructures with reversible tunable optical properties. Albeit challenging, further control using thermal external stimuli to tune the local environment of gold nanoparticles embedded in V02 host matrix would be ideal for the design of responsive functional nanocomposites. We prepared Au-V02 nanocomposite thin films by the inverted cylindrical reactive magnetron sputtering (ICMS) known as hollow cathode magnetron sputtering for the first time and report the reversible tuning of surface plasmon resonance of Au nanoparticles by only adjusting the external temperature stimuli. The structural, morphological, interfacial analysis and optical properties of the optimized nanostructures have been studied. ICMS has been attracting much attention for its enclosed geometry and its ability to deposit on large area, uniform coating of smart nanocomposites at high deposition rate. Before achieving the aforementioned goals, a systematic study and optimization process of V02 host matrix has been done by studying the influence of deposition parameters on the structural, morphological and optical switching properties of V02 thin films. A reversible thermal tunability of the optical/dielectric constants of V02 thin films by spectroscopic ellipsometry has been intensively also studied in order to bring more insights about the shift of the plasmon of gold nanoparticles imbedded in V02 host matrix.

Un nouveau moteur de recherche embarqué conçu pour les objets intelligents. Ces dispositifs sont généralement équipés d'extrêmement de faible quantité de RAM et une grande capacité de stockage Flash NANAD. Pour faire face à ces contraintes matérielles contradictoires, les moteurs de recherche classique privilégient soit la scalabilité en insertion ou la scalabilité en requête, et ne peut pas répondre à ces deux exigences en même temps. En outre, très peu de solutions prennent en charge les suppressions de documents et mises à jour dans ce contexte. nous avons introduit trois principes de conception, à savoir y Write-Once Partitioning, Linear Pipelining and Background Linear Merging, et montrent comment ils peuvent être combinés pour produire un moteur de recherche intégré concilier un niveau élevé d'insertion / de suppression / et des mises à jour. Nous avons mis en place notre moteur de recherche sur une Board de développement ayant un représentant de configuration matérielle pour les objets intelligents et avons mené de vastes expériences en utilisant deux ensembles de données représentatives. Le dispositif expérimental résultats démontrent la scalabilité de l'approche et sa supériorité par rapport à l'état des procédés de l'art. / A new embedded search engine designed for smart objects. Such devices are generally equipped with extremely low RAM and large Flash storage capacity. To tackle these conflicting hardware constraints, conventional search engines privilege either insertion or query scalability but cannot meet both requirements at the same time. Moreover, very few solutions support document deletions and updates in this context. we introduce three design principles, namely Write-Once Partitioning, Linear Pipelining and Background Linear Merging, and show how they can be combined to produce an embedded search engine reconciling high insert/delete/update rate and query scalability. We have implemented our search engine on a development board having a hardware configuration representative for smart objects and have conducted extensive experiments using two representative datasets. The experimental results demonstrate the scalability of the approach and its superiority compared to state of the art methods.

Low slope roofs are roofs with an inclination between 1:16 and 1:4 and have been constructed and preferred for many years due to the benefits they present. The goal of the present work is to study the following problems of low slope roofs, as they are suggested by previous relevant theses and the current needs of the market. Moisture transfer in low slope roofs with constant exposure to high levels of relative humidity. Is protection against corrosion required for steel beams placed directly under the external membranes? If yes, what kind of protection is that? Roof drainage on low slope roofs The study of the first subject was based on simulations of this type of structures in order to see how external moisture affects the moisture level and the potential for corrosion on steel beams. The main goal was to conclude whether we can actually build inverted roofs with steel plates or beams lying right under the roof membrane and what kind of protection is more appropriate to apply, in case it is required. According to the literature review conducted on roof structures, corrosion and corrosion protection, as well as the results of the simulations, the main factor defining the corrosion potential is the indoor environment. Moreover, paint coating seems to be the indicated anticorrosive protection. Regarding drainage, the study focused on the literature review of the current situation, the solutions applied, the existing regulations and guidelines regarding the type of systems used (full flow or gravity, internal or external), the construction of drainage valleys (inclined or horizontal) and the placement and dimensioning of drains and overflows, in order to create a short handbook with issues to be considered by the roof engineer. The main conclusions are that drain valleys are suggested to be constructed completely horizontal, in order to facilitate the cooperation between drains, and that full-flow systems are more efficient than gravity ones and should be preferred, as long as the roof is not exposed to solid material and prone to its accumulation around drains (e.g. roofs covered with vegetation or stone ballast, with overhanging or nearby trees).

This study inquires as to whether Walmart’s sustainability campaign represents a sincere and holistic change throughout the company’s global supply chain or if it is simply a public relations campaign which caters to the growing target market of “next-generation” consumers and justifies further expansion into “emerging markets”. A critical analysis of Walmart’s sustainability discourse is presented, using transcribed texts of various corporate and publicitygeared publications. Frequently utilized terms and themes are identified throughout the big-box retailer’s sustainability campaign which convey a distinctly Neoliberal ethos—a political economy which lies at the heart of current practices of institutional unsustainability—and emphasize the role of the atomized individual—who may purchase protection from environmental risks via green products. Other themes, which are commonly associated with sustainability research, are glaringly absent: subsidiarity; human rights; steady-state economics; economic inequity; the precautionary principle. This research aims to shed light on the prospects for the sustainability of green overconsumption, which Walmart is leading the way in promoting, and for the continuation of the modern economistic zeitgeist into the twenty-first century.

The focus of this document is on the design, modeling, and control of a self-balancing two wheel robot, hereafter referred to as the balance bot, driven by independent brushless DC (BLDC) motors. The balance bot frame is composed of stacked layers allowing a lightweight, modular, and rigid mechanical design. The robot is actuated by a pair of brushless DC motors equipped with Hall effect sensors and encoders allowing determination of the angle and angular velocity of each wheel. Absolute orientation measurement is accomplished using a full 9-axis IMU consisting of a 3-axis gyroscope, a 3-axis accelerometer, and a 3-axis magnetometer. The control algorithm is designed to minimize deviations from a set point specified by an external radio remote control, which allows the remote operator to steer and drive the bot wirelessly while it remains balanced. Multiple dynamic models are proposed in this analysis, and the selected model is used to develop a linear-quadratic regulator based state-feedback controller to perform reference tracking. Controller tracking performance is improved by incorporating a prefilter stage between the setpoint command from the remote control and the state-feedback controller. Modeling of the actuator dynamics is considered brie y and is discussed in relation to the control algorithm used to balance the robot. Electrical and software design implementations are also presented with a focus on effective implementation of the proposed control algorithms. Simulated and physical testing results show that the proposed balance bot and controller design are not only feasible but effective as a means of achieving robust performance under dynamic tracking profiles provided by the remote control.

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The Intergovernmental Panel on Climate Change 2018 highlights the importance of short-lived greenhouse gasses to combat global warming. This study explores the relationship between Gross Domestic Product per capita and methane per capita. The relationship is explored in relation to the Environmental Kuznets Curve theory where the subjects to examination used are High Income Countries and Low Income Countries based on United Nation classifications in 2019. In total 47 countries are examined where 30 countries are High Income Countries and 17 are Low Income Countries. The relationships are examined for the time periods 1970 to 2017 through Fixed Effect Models. To improve accuracy additional control variables are added: Population in agriculture (% of total employment), balance of payments and forest areas. With the added control variables, the time frame used in Fixed Effect Models changes to 1991 to 2017. The different Fixed Effect Models provide inverted U-shaped relationships for Low Income Countries and uncertain results for High Income Countries according to the Environmental Kuznets Curve.

In this paper the two reinforcement learning algorithmsQ-learning and deep Q-learning (DQN) are used tobalance an inverted pendulum. In order to compare the two, bothalgorithms are optimized to some extent, by evaluating differentvalues for some parameters of the algorithms. Since the differencebetween Q-learning and DQN is a deep neural network (DNN),some benefits of a DNN are then discussed.The conclusion is that this particular problem is simple enoughfor the Q-learning algorithm to work well and is preferable,even though the DQN algorithm solves the problem in fewerepisodes. This is due to the stability of the Q-learning algorithmand because more time is required to find a suitable DNN andevaluate appropriate parameters for the DQN algorithm, than tofind the proper parameters for the Q-learning algorithm. / I denna rapport används två algoritmer inom förstärkningsinlärning och djup Q-inlärning (DQN), för att balancera en omvänd pendel. För att jämföra dem så optimeras algoritmerna i viss utsträckning genom att testa olika värden för vissa av deras parametrar. Eftersom att skillnaden mellan Q-inlärning och DQN är ett djupt neuralt nätverk (DNN) så diskuterades fördelen med ett DNN. Slutstatsen är att för ett så pass enkelt problem så fungerar Q-inlärningsalgoritmen bra och är att föredra, trots att DQNalgoritmen löser problemet på färre episoder. Detta är pågrund av Q-inlärningsalgoritmens stabilitet och att mer tid krävs för att hitta ett passande DNN och hitta lämpliga parametrar för DQN-algoritmen än vad det krävs för att hitta bra parametrar för Q-inlärningsalgoritmen. / Kandidatexjobb i elektroteknik 2021, KTH, Stockholm

The inverted T-beam bridge system provides an accelerated bridge construction alternative for short-to-medium-span bridges. The system consists of adjacent precast inverted T-beams finished with a cast-in-place concrete topping. The system offers enhanced performance against reflective cracking, and reduces the likelihood of cracking due to time dependent effects. The effects of transverse bending due to concentrated wheel loads are investigated with respect to reflective cracking. Transverse bending moment are quantified and compared to transverse moment capacities provided by a combination of various cross-sectional shapes and transverse connections. A design methodology for transverse bending is suggested. Tensile stresses created due to time dependent and temperature effects are quantified at the cross-sectional and structure level and strategies for how to alleviate these tensile stresses are proposed. Because differential shrinkage is believed to be one of the causes of deck cracking in composite bridges, a study on shrinkage and creep properties of seven deck mixes is presented with the goal of identifying a mix whose long terms properties reduce the likelihood of deck cracking. The effects of differential shrinkage at a cross-sectional level are numerically demonstrated for a variety of composite bridge systems and the resistance of the inverted T-beam system against time dependent effects is highlighted. End stresses in the end zones of such a uniquely shaped precast element are investigated analytically in the vertical and horizontal planes. Existing design methods are evaluated and strut-and-tie models, calibrated to match the results of 3-D finite element analyses, are proposed as alternatives to existing methods to aid designers in sizing reinforcing in the end zones. Composite action between the precast beam and the cast-in-place topping is examined via a full scale test and the necessity of extended stirrups is explored. It is concluded that because of the large contact surface between the precast and cast-in-place elements, cohesion alone appears to provide the necessary horizontal shear strength to ensure full composite action. Live load distribution factors are quantified analytically and by performing four live loads tests. It is concluded that AASHTO's method for cast-in-place slab span bridges can be conservatively used in design. / Ph. D.