In this thesis, we utilized CCFL as the sidelight of backlight module. At the same time, we designed many um-size and 45 degree stepped microstructures on the bottom of LGP to reach the goal of uniform plane light due to its diffraction effect. Then mostly incident light can be induced to the ejected surface by once of total reflection. This way can avoid light energy being wasted, which always happens in traditional LGP design because of several times of diffraction and reflection occurred in front of light being ejected out of LGP. Moreover, stepped microstructures LGP combines the functions of reflector, diffuser, and prism film, so it can lower material cost. Relating to geometrical optics, we simulated our design with TracePro software to verify the effect we expect; relating to wave motion theory, we verified it by Definite Difference Method and programming with Matlab language. At last, we made samples to verify the above simulations and theories.

<p>Den vård som har starkast evidens vid behandling av tvångssyndrom, Obsessive Compulsive Disorder (OCD), är kognitiv beteendeterapi (KBT), innehållande exponering och responsprevention. Idag är tillgången till denna vård begränsad främst på grund av för få behandlare. Tidigare forskning pekar på att personer med OCD kan bli hjälpta av mindre terapeutintensiva behandlingar. Att leverera vård stegvis med ökande behandlingsintensitet; Stepped Care, kan vara ett sätt att öka tillgängligheten av KBT. Denna pilotstudie har undersökt Stepped Care för OCD i form av tre steg, på Ångestenheten, Karolinska Universitetssjukhuset. Det primära syftet har varit att bidra till kunskapsinsamlingen kring Stepped Care vid OCD. Sammanlagt 19 vuxna patienter ingår i pilotstudien. 8 blev förbättrade efter självhjälp, 5 efter gruppbehandling, 2 efter individualterapi samt 4 bortfall. Av dessa behöll 7 av självhjälps-, 3 av grupp- och ingen av individualpatienterna sina framsteg vid en uppföljning 12 veckor efter avslutad behandling. Totalt tog behandlingen 244 terapeuttimmar i anspråk, vilket är mer än en halvering mot traditionell individualbehandling. Resultaten tyder på att Stepped Care är ett intressant alternativ för att effektivisera och öka tillgängligheten av vård för OCD-patienter.</p>

Den vård som har starkast evidens vid behandling av tvångssyndrom, Obsessive Compulsive Disorder (OCD), är kognitiv beteendeterapi (KBT), innehållande exponering och responsprevention. Idag är tillgången till denna vård begränsad främst på grund av för få behandlare. Tidigare forskning pekar på att personer med OCD kan bli hjälpta av mindre terapeutintensiva behandlingar. Att leverera vård stegvis med ökande behandlingsintensitet; Stepped Care, kan vara ett sätt att öka tillgängligheten av KBT. Denna pilotstudie har undersökt Stepped Care för OCD i form av tre steg, på Ångestenheten, Karolinska Universitetssjukhuset. Det primära syftet har varit att bidra till kunskapsinsamlingen kring Stepped Care vid OCD. Sammanlagt 19 vuxna patienter ingår i pilotstudien. 8 blev förbättrade efter självhjälp, 5 efter gruppbehandling, 2 efter individualterapi samt 4 bortfall. Av dessa behöll 7 av självhjälps-, 3 av grupp- och ingen av individualpatienterna sina framsteg vid en uppföljning 12 veckor efter avslutad behandling. Totalt tog behandlingen 244 terapeuttimmar i anspråk, vilket är mer än en halvering mot traditionell individualbehandling. Resultaten tyder på att Stepped Care är ett intressant alternativ för att effektivisera och öka tillgängligheten av vård för OCD-patienter.

<p> A report follows in which five different conditions of support of stepped crane columns were investigated. In each case the curvature or moment equations representing the column in its just-buckled condition are determined. The general solution of each differential equation is then found and solved in terms of the boundary conditions to obtain a transcendental equation which gives the critical buckling length. This transcendental equation is solved for the lowest possible value to get the critical buckling length. This lowest value is compared to the Euler critical buckling value in order to get the effective length factor.</p> / Thesis / Master of Engineering (MEngr)

The straight line calm water performance of stepped planing hulls has been studied experimentally, by prediction method, and numerically. A model test was conducted to provide a systematic understanding of the effects that displacement and step location have on the performance of a stepped planing hull. Ten different step configurations were tested at three different displacements and over a range of four different speeds in calm water. Seven of these configurations were tested at two different Longitudinal Center of Gravity (LCG) locations. Of all the configurations tested, the stepped hull configurations showed reduced resistance compared to the unstepped hull. The configurations with the largest step height aft showed the least amount of resistance over the speed range tested. Increasing displacement and shifting LCG had similar effects on craft performance for both stepped and unstepped hulls. The current stepped hull prediction method was expanded to include a three dimension wave profile and the ability for the stagnation line to cross the step. Using previous model test data and existing two dimension wave profile equations, a single equation was developed to predict the three dimension wave profile aft of a step. Formulations were added to Savitsky's planing prediction method to include very high speed craft and chines dry conditions. Lastly, two simulations were performed using two computational fluid dynamics numerical tools, OpenFOAM, and NFA. The results of these simulations were compared to the experimental test results to assess each code's relative strengths and weaknesses for use in detail design of stepped planing craft. / Ph. D.

The work presented in this thesis aims at investigating the attachment of lightning flashes to wind turbines. Modern wind turbines are highly exposed to lightning strikes, due to the increase of their height and the rotation of the blades. Upward lightning is the dominant mechanism of lightning strikes to them. Therefore, this study evaluates the initiation of the initial upward leader discharge and the process of lightning attachment of dart leaders taking place prior to the first return stroke in upward flashes. This work extends the self-consistent leader inception and propagation model (SLIM) to evaluate the lightning attachment of dart and dart-stepped leaders to grounded objects. SLIM was originally proposed to evaluate the lightning attachment of stepped leaders. Unlike the well-studied lightning attachment of stepped leaders, upward connecting leaders initiated in response to dart and dart-stepped leaders develop under a significantly faster change of the ambient electric field. Additionally, these connecting leaders could develop in warm air pre-conditioned by the previous strokes in the same flash. An analytical expression to evaluate the charge required to thermalize the connecting leader per unit length is also developed in the extended model. This model is validated through the analysis of three attachment events recorded in rocket-triggered lightning experiments. Good agreement between the predicted properties of the upward leaders and the measurements has been found. The model is utilized to evaluate the different conditions where connecting leaders can develop prior to the return strokes in upward lightning. The extended model of SLIM is also applied to study the interception of lightning dart leaders by upward connecting leaders initiated from wind turbines. The evaluation considers the influence of the return stroke peak current, the blade rotation and wind on the attachment of lightning dart leaders to wind turbines. The probability of lightning strikes to the receptors along the blade and on the nacelle is calculated for upward lightning flashes. It is shown that the lightning attachment of dart leaders is a mechanism that can explain the lightning damages to the inboard region of the blades (more than 10 meters from the tip) and the nacelle of wind turbines. Furthermore, the critical stabilization electric field required to initiate upward lightning from wind turbines is evaluated for both ‘self-initiated’ and ‘other-triggered’ upward flashes. The calculation shows that the stabilization electric field of an operating wind turbine periodically changes due to the rotation of its blades.  The initiation of upward lightning is greatly facilitated by the electric field change produced by nearby lightning events. However, the rate of rise of the electric field only has a weak impact on the stabilization electric field. The evaluation of the stabilization electric field provides essential information needed for the estimation of the incidence of upward lightning to wind turbines. / <p>QC 20161201</p>

Barragens são utilizadas há séculos para diversas finalidades. Em diversas barragens os vertedouros são constituídos de degraus com o objetivo de aumentar a dissipação de energia. A presente pesquisa objetiva a caracterização dos esforços atuantes em vertedouros em degraus, através da análise da variação das pressões atuantes ao longo da calha e suas distribuições na faces do degraus. Com esse objetivo, são realizadas análises sobre modelos de vertedouros com declividade de 1V:0,75H e degraus de 3, 6 e 9 centímetros. São analisados os campos de pressões nos degraus e comparados com os resultados disponíveis na bibliografia. Também são propostos modelos para previsão de pressões nos patamares e espelhos dos degraus bem como dos esforços resultantes. Além disso, são realizadas transposições dos resultados para a escala de protótipo, inclusive com a análise da possibilidade de cavitação na estrutura. Como constatação geral sobre as pressões nos espelhos verifica-se que os esforços de tração e compressão têm magnitudes relativamente semelhantes, sendo mais intensas as pressões negativas. Sobre as pressões máximas nos patamares, destaca-se que os valores máximos de compressão ocorreram no final da calha, percebendo-se que as menores vazões geraram maiores valores de coeficientes de pressões. As variações da compressão nas faces dos patamares apresentam crescimento, no sentido da extremidade com o espelho acima deste para o vértice com o espelho abaixo do mesmo patamar. Nas faces dos espelhos, percebe-se que os mais extremos de tração são observados na parte superior, próximo à quina com os patamares. / Dams have been used throughout the centuries for a plethora of purposes. Several designs employ steps on the spillways in order to increase the power dissipation. The present research aims to characterize the forces acting on stepped spillways by analyzing both the variation of pressures acting along the pipeline and their distributions on the faces of the steps. In order to achieve this purpose, observations and discussions regarding spillways models with slope characterized as 1V: 0.75H and steps ranging from 3 to 9 centimeters are conducted. The pressure fields measured in the steps were analyzed and compared with results available in the literature. Sub sequentially, models to predict pressures on the faces of the steps and the resulting efforts were proposed. Finally, transpositions were performed on a prototype scale. Generally, it was found that the magnitude of tensile and compressive forces on the vertical faces are relatively similar, being the negative pressure slightly higher on all cases. During the experiments, it was observed that compression forces increased thought the length of the step’s horizontal face, peaking at the edge. It was also noticed that lower flows generated higher pressure coefficients. The measured compression on the horizontal faces of the step and its variation increase towards the edge of the step. It is perceived that the maximum tensile is observed on the top of the step’s vertical faces, near the corner with the horizontal faces.

Computational Science and Engineering (CSE) applications often exhibit the pattern of adaptive mesh applications. Adaptive mesh algorithm starts with a coarse base-level grid structure covering entire computational domain. As the computation intensified, individual grid points are tagged for refinement. Such tagged grid points are dynamically overlayed with finer grid points. Similarly if the level of refinement in a cell is greater than required, all such regions are replaced with coarser grids. These refinements proceed recursively. We have developed an object-oriented framework enabling time-stepped adaptive mesh application developers to convert their sequential applications to MPI applications in few easy steps. We present in this thesis our positive experience converting such application using our framework. In addition to the MPI support, framework does the grid expansion/contraction and load balancing making the application developer’s life easier.

The purpose of this thesis is aimed to predict that what kind of adhesive bonded joint of composite tube the can obtain more efficient structure. APC-2 sixteen-layer laminates of AS-4/PEEK were used as adherends, including cross-ply [0/90]4S and quasi-isotropic [0/45/90/-45]2S laminates. And we use two different kinds of adhesive bonded joints, including stepped lap joint and scarf lap joint. On the aspect of numerical analysis, we employ finite element method incorporate with the software of ANSYS 5.5.1 to obtain the distribution of stress on adhesive bonded joint. In this thesis, there are two kinds of geometrical shape on stepped lap joint. The bonded layer height h that is vertical to the axis of the composite tube is 2mm and 5mm. There are also two kinds of the geometrical shape on scarf lap joint. The angle £\ between the bonded layer and the axis of the composite tube is 30¢Xand 45¢X.The boundary condition on one side of the composite tube is assumed to be fixed. The other side of the composite tube is due to torsion. According to the numerical result, the stepped lap joint with h=5mm and quasi-isotropic [0/45/90/-45] occurs minimum von Mises stress, and we predict this kind of joint can sustain the maximum external load and obtain better efficiency. In this thesis, the geometrical shape, size and the direction of laminates of the joint will effect the distribution of stress.

Stepped chutes have been used as hydraulic structures for more than 3.5 millennia for different purposes: For example, to dissipate energy, to enhance aeration rate in the flow and to comply with aesthetical functions. They can be found acting as spillways in dams and weirs, as energy dissipators in artificial channels, gutters and rivers, and as aeration enhancers in water treatment plants and fountains. Spillways are used to prevent dam overtopping caused by floodwaters. Their design has changed through the centuries. In ancient times, some civilizations used steps to dissipate energy in open channels and dam over-falls in a similar fashion as natural cascades. However, in the first half of the twentieth century, the use of concrete became popular and the hydraulic jump was introduced as an efficient energy dissipator. In turn, the use of a stepped geometry became obsolete and was replaced with smooth chutes followed by hydraulic jump stilling basins. In recent years, new construction techniques and materials (Roller Compacted Concrete RCC, rip-rap gabions, wire-meshed gabions, etc.) together with the development of new applications (e.g. re-aeration cascades, fish ladders and embankment overtopping protection or secondary spillways) have allowed cheaper construction of stepped chutes, increasing the interest in stepped chute design. During the last three decades, research in the hydraulics of stepped spillways has been very active. However, studies prior to 1993 neglected the effect of free-surface aeration. A number of studies since this time have focused on air-water flows in steep chutes (θ ≈ 50o). But experimental data is still scarce, and the hydraulic performance of stepped cascades with moderate slope is not yet understood. This study details an experimental investigation of physical air-water flow characteristics down a stepped spillway conducted in two laboratory models with moderate slopes: the first model was a 3.15 m long stepped chute with a 15.9o slope comprising two interchangeable-height steps (h = 0.1 m and h = 0.05 m); the second model was a 2.5 m long, stepped channel with a 21.8o slope comprising 10 steps (h = 0.1 m). Different arrangements of turbulence manipulators (vanes) were also placed throughout the chute in the second model. A broad range of discharges within transition and skimming flow regimes was investigated to obtain a reliable representation of the air-water flow properties. Measurements were conducted using single and double tip conductivity probes at multiple span wise locations and at streamwise distances along the cavity between step edges to obtain a complete three-dimensional representation of the flow. Although the present study was conducted for two moderate slope chutes (θ = 15.9º & 21.8o), it is believed that the outcomes are valid for a wider range of chute geometry and flow conditions. The purpose of this study is to improve the understanding of turbulent air-water flows cascading down moderate slope stepped chutes, and gain new understandings of the interactions between aeration rate, flow turbulence and energy dissipation; scale effects are also investigated. The study provides new, original insights into air-water turbulent flows cascading down moderate slope stepped spillways not foreseen in prior studies, thus contributing to improve criterion designs. It also presents an extensive experimental database (available in a CD-ROM attached at the end of this thesis) and a new design criterion that can be used by designers and researchers to improve the operation of stepped chutes with moderate slopes. The present thesis work included a twofold approach. Firstly, the study provided a detailed investigation of the energy dissipative properties of a stepped channel, based upon detailed airwater flow characteristics measurements conducted with sub-millimetric conductivity probes. Secondly, the study focused on the microscopic scale properties of the airwater flow, using the experimental data to quantify the microscopic scale physical processes (e.g. momentum transfer, shear layer development, vertical mixing, airbubbles/ water-droplets break-up and coalescence etc.) that are believed to increase the flow resistance in stepped canals. The study highlighted the tridimensionality of skimming flows and hinted new means of enhancing flow resistance by manipulating turbulence in the stepped chute. Basic dimensional analysis results emphasized that physical modelling of stepped chutes is more sensitive to scale effects than classical smooth-invert chute studies and thus suggested that the extrapolation of results obtained from heavily scaled experimental models should be avoided. The present study also demonstrated that alterations of flow recirculation and fluid exchanges between free-stream and cavity flow affects drastically form losses and in turn the rate of energy dissipation. The introduction of vanes demonstrated simple turbulence manipulation and form drag modification that could lead to more efficient designs in terms of energy rate dissipation without significant structural load on the stepped chute.