We study thoroughly Casimir energy and Casimir force in a rectangular cavity and piston with various boundary conditions, for both scalar field and electromagnetic (EM) field. Using the cylinder kernel approach, we find the Casimir energy exactly and analyze the Casimir energy and Casimir force from the point of view of closed classical paths (or optical paths). For the scalar field, we study the rectangular cavity and rectangular piston with all Dirichlet conditions and all Neumann boundary conditions and then generalize to more general cases with any combination of Dirichlet and Neumann boundary conditions. For the EM field, we first represent the EM field by 2 scalar fields (Hertz potentials), then relate the EM problem to corresponding scalar problems. We study the case with all conducting boundary conditions and then replace some conducting boundary conditions by permeable boundary conditions. By classifying the closed classical paths into 4 kinds: Periodic, Side, Edge and Corner paths, we can see the role played by each kind of path. A general treatment of any combination of boundary conditions is provided. Comparing the differences between different kinds of boundary conditions and exploring the relation between corresponding EM and scalar problems, we can understand the effect of each kind of boundary condition and contribution of each kind of classical path more clearly.

No description available.

Titanium dioxide (TiO2) attracts extensive attention due to its widespread technological and environmental applications. This study seeks to investigate the surface charging behavior of the two TiO2 polymorphs, anatase and rutile, using Flow Adsorption Microcalorimetry (FAMC). FAMC allows direct quantitative measurement of the heat of a surface reaction; these calorimetric heats are directly proportional to the surface charge. Determining the magnitude of positive and negative charges at the surface over a range of pHs allows for the determination of the point of zero net charge (PZNC) via a unique calorimetric method that removes many of the shortcomings related to the other analytical techniques used for such measurements.

Zero-point energy is the energy of the vacuum. Disturbing the vacuum results in a change in the zero-point energy. In 1948, Casimir considered the change in the zeropoint energy when the vacuumis disturbed by two parallelmetal plates. The plates disturb the vacuum by restricting the quantum fluctuations of the electromagnetic field. Casimir found that the change in the zero-point energy implies that the plates are attracted to each other. With the recent advances made in the experimental verification of this remarkable result, theoretical interest has been rekindled. In addition to the original parallel plate configuration, several other boundaries have been studied. In this thesis, two novel boundaries are considered: elliptic-cylindrical and spheroidal. The results for these boundaries lead to the conjecture that zero-point energy does not change for small deformations of the boundary that preserve volume. Assuming the conjecture, it is shown that zero-point energy plays a stabilizing role in quantum chromodynamics, the leading theory of the strong interaction.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The present study aims to present the general way in which Husserl understand the meaning of body as body-live from the bias of the sensations as well as the general sense of the body as zero-point (Nullpunkt), positioning this study from paragraphs §36-37 and §41 of the work Ideas II. In the first chapter we present the historical and philosophical reasons for the theme investigation, the etymological and philosophical origins of the term Leib and general aspects of the "body" in Ideas II work. In a second time, we drove a study on the constitution of the body as the body alive from the bias of sensations. In the third chapter of this work, we study the meaning of zero-point (Nullpunkt) body and the way the body from its zero (Null) position is originally the show look of things (Ding). / O presente estudo tem como objetivo geral apresentar o modo como Husserl compreende o sentido de corpo como corpo-vivo a partir do viés das sensações, bem como, o sentido de corpo como ponto-zero (Nullpunkt), posicionando esse trabalho nos parágrafos §36-37 e §41 da obra Ideias II. No primeiro capítulo apresentaremos as razões histórico-filosóficas que justificam a investigação da referida temática, as origens etimológicas e filosóficas do termo Leib e os aspectos gerais do corpo na obra Ideias II. Em um segundo momento, dirigiremos um estudo sobre a constituição do corpo como corpo-vivo a partir do viés das sensações. No terceiro capítulo deste trabalho, estuda-se o sentido de corpo como ponto-zero (Nullpunkt) e o modo como o corpo a partir de sua posição zero (Null) constitui originariamente o aparecer visual das coisas (Ding).

Detta examensarbete har utförts i Karlskoga på två företag, Lasertech LSH AB och PartnerTech Karlskoga AB, där uppdraget bestod i att med en metodutveckling hitta ett generellt angreppssätt som man kan förhålla sig till för att förenkla efterbearbetningen av en additivt tillverkad (AT) detalj. Fortsättningsvis kommer additiv tillverkning att benämnas AT i texten. Svårigheten ligger i att spänna upp och mäta in en detalj i en CNC-maskin som nästan är färdig och saknar självklara inmätning- och inspänningsytor. Syftet med arbetet var att hitta en generell metod att använda sig av för att lösa dessa svårigheter vilket leder till en säkrare och effektivare tillverkning. Parallellt med problemlösningen gjordes även en fallstudie där bägge företagen har en AT produkt som ska bearbetas i CNC-maskin. Problemen klargjordes med hjälp av ett funktionsmedelträd och lösningar togs fram med hjälp av konceptgenerering för att få fram så många och bra lösningar som möjligt. Genom att ta fram dessa koncept och möjligheten att kombinera dessa med varandra skapades en metod som löser inmätning- och inspänningsproblemen och visade sig vara användbar i fallstudien. Dessa koncept ses som en generell och bra lösning på ovanstående problem. Fortsatt arbete och utbildning kommer att krävas för att ytterligare testa metoderna och ge ökad kunskap om AT för att underlätta tillverkningsprocessen. / This thesis has been carried out in Karlskoga at the two companies, Lasertech LSH AB and PartnerTech Karlskoga AB, where the assignment consisted of using a methodological development to find a general approach that can be used to simplify the processing of an additive manufactured (AM) part. The challenge is to rig and calibrate a detail in a CNC machine that is nearly finished that lacks obvious faces to rig and calibrate the part in the machine. The aim of the work is to find a general method that can be used to resolve these difficulties, leading to a safer and more efficient manufacturing. Parallel to the solution of the problem, a case study will also be done where both companies have a product that will be additive manufactured (AM) and processed in the CNC machine. The problems were clarified by using a functional-medium-trees (funktionsmedelträd) and solutions were developed using the concept generation to get as many good solutions as possible. By developing these concepts and the ability to combine these with each other a method that solves the problems with the rigging and calibration was created and proved to be useful in the case study. We see these concepts as general and a good solutions to the problems above. Further work and training will be required to further test the methods and increase knowledge about AM production to facilitate the manufacturing process.

No description available.

This thesis presents a new theoretical formalism which incorporates dynamical effects in atomistic electronic structure and related calculations. This research, fundamental by nature, brings about a deeper understanding of the dynamical processes in a range of materials. This establishes technologically important correlation with experimentally measured macroscopic properties and materials characterization. This method—the first of its kind—is a natural and long overdue extension of customary adiabatically separated time-independent electronic structure methods. It accounts explicitly for atomic motion due to thermal and zero-point vibration. The approach developed requires no direct treatment of time dependence in the quantum mechanical calculations, making the method widely applicable utilizing currently available electronic structure and ab-initio molecular dynamics software. The formalism is extensively applied and demonstrated for the linear optical response of bulk gallium arsenide and electronic structure of the C(111) 2 x 1 surface. Both cases are complimented by comparison of key observables to experimental data which may be used to judge the quality of the results. The results are found to be in good agreement with experimental data, with most exceptions being readily explainable and well understood.

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Indiana University-Purdue University Indianapolis (IUPUI) / Based on plane wave DFT calculation, we carried out micro level investigation of hydrogen storage in nanoporous silicon (npSi). One quarter of a hexagonal pore with Palladium catalyst placed at the surface has been studied for hydrogen dissociation, spillover, bond hopping, and diffusion for both single catalyst atom and small catalyst cluster consisting of multiple catalyst atoms. All the DFT computations were done in one of the biggest research supercomputer facilities of the world, Big Red II. We opted ABINIT, an open source DFT tool for our computations. Our calculation revealed low dissociation, spillover, and bond hoping energy barrier. The energy required to be provided from external sources to fully recharge the storage medium from a gaseous source at a completely empty state has also been evaluated. Hydrogen diffusion along the inner surface of the pore as a means of bond hopping and the possibility of quantum tunneling, a low temperature phenomena used to spontaneously go over an otherwise less likely high energy barrier have been studied as well. Using these micro level parameter values evaluated from the DFT study, the performance of any potential hydrogen storage material can be compared to a set of characteristics sought in an efficient storage media. Thus, the micro scale feasibility of this novel npSi material based hydrogen storage technology was studied as a part of a STTR Phase I project.