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Gas-phase electron diffraction (GED) is the method of choice for determining the structures of molecules containing between two and 100 atoms, free from intermolecular interaction. However, for many molecules it becomes necessary to augment the experimental GED data with information from other sources. The SARACEN method, used routinely at Edinburgh when determining structures, allows computed parameters from ab initio and density functional theory (DFT) calculations to be used as extra data in the GED refinement process. This thesis describes the determinations of the gas-phase structures of molecules that contain heavy p-block elements, including examples from Groups 13, 14, 15 and 16. Each of the compounds studied was solid at room temperature, requiring heating to produce a suitable vapour pressure and vaporisation rate and testing the existing electron diffraction apparatus to its limits. Use was made of a new heated reservoir, recently developed in Edinburgh by a previous PhD student, which has allowed compounds to be studied that were previously inaccessible. The molecules that were studied during the course of this degree are: In(P3C2But2), In(P2C3But3), Sn(P2C2But2), Sb2(C6F6)3, Bi2(C6F6)3, Se(SCH3)2 and Te(SCH3)2. While determining the structures of these molecules, accurate theoretical geometries have been obtained using both ab initio and DFT methods. As a result a better understanding has been achieved of which methods are suitable for use in calculating the structures of molecules with heavy p-block elements. The use of pseudopotentials as opposed to all-electron basis sets proved necessary when performing calculations on such large molecules with heavy atoms. The extent to which these pseudopotentials, especially ones that consider very few electrons to be in the valence shell of an atom, can affect the calculated geometries has been shown to be considerable. In addition, methods being developed to compute vibrational corrections for gas-phase structure determination have been extended to the crystalline phase. Molecular dynamics simulations have been used to derive the effects of vibrations on average nuclear positions, relative to equilibrium positions. The differences, when applied to coordinates obtained experimentally by neutron diffraction yield experimental equilibrium structures.

In April 2007 we contacted Lennart Augustsson at Designpartners AB in Västerås. He came up with the idea to investigate and evaluate their construction of a interaction beam, CSB-beam. CSB is short for Connector Interaction beam. The beam is based on a horizontal C-profile of high-tensile steel and in the bottom of the profile are vertical flat bar welded so called block connectors. These block anchorsare also made of hightensilesteel. Their task is to create collaboration between the steel and the concrete. The dimensioning of the block connectors is done according to the Swedish standard SSENV199411.The purpose of this study is to evaluate and control the formula used for the dimensioning which is found in SS-ENV 1994-1-1.There has been two main parts of this exam work. Part 1: Theoretical preliminary investigations,consisting of calculations and literature studies of block anchors. Part 2: Practical testloads of four prefabricatedCSB-beams.The results of the two parts were thencompared to see if theory corresponded to reality. The result shows that the comparison of the formula in Swedish standard, SS-ENV 1994-1-1 can be used for dimensioning of block connectors in interaction beams.

We have investigated the use of the graphical processing unit to accelerate the software package DarkSUSY. DarkSUSY is, among other things, used for calculating the dark matter relic density -- an measurable quantity -- given the supersymmetric neutralino, χ, as a dark matter candidate. Supersymmetric theories have many free parameters and we want to calculate the relic density for large areas of the parameter space. The results can then be compared with observations and to constrain the parameters. A faster DarkSUSY would allow for larger searches in the parameter space. We modified DarkSUSY using Nvidia's CUDA platform and wrote a program that, by using the GPU, calculates the χ + χ <-> W+ + W- contribution to the annihilation cross-section. Our initial try was only negligible faster than our non-CUDA program due to under-utilization of the GPU, but solving that the program was 47 times faster than the reference program. We also report on difficulties we faced, both solved and unsolved so the reader can make an informed decision on the worth of rewriting so that the heavy calculations in DarkSUSY use the GPU. / Vi har undersökt om man kan använda grafikkortet för att få mjukvarupaketet DarkSUSY snabbare. DarkSUSY används, bland annat, för att beräkna relikdensiteten av mörk materia -- en mätbar kvantitet -- användandes den supersymmetriska neutralinon, χ, som mörk materia-kandidat. Supersymmetriska teorier har många fria parametrar och vi vill beräkna relikdensiteten för stora områden av parameterrummet. Resultaten kan sedan jämföras med observationer för att begränsa parametrarna. Ett snabbare DarkSUSY skulle tillåta större sökningar i parameterrummet. Vi modifierade DarkSUSY med hjälp av Nvidias CUDA-platform och skrev ett program som, genom att använda grafikkortet, beräknar χ + χ <-> W+ + W- kanalens bidrag till annihilationstvärsnittet. Vårt första försök var bara försumbart snabbare än vårt icke-CUDA program på grund av underanvändning av grafikkortet. Men med det åtgärdat så var programmet 47 gånger snabbare än referensprogrammet. Vi rapporterar också de problem vi stött på, både de vi löste och de vi inte löste. Detta så att läsaren kan avgöra värdet av att omarbeta så att alla de beräkningsintensiva delarna av DarkSUSY använder grafikkortet.

Density functional theory (DFT) is used to study the reactivity of Pt and Pt-M (M: Pd, Co, Ni, V, and Rh) alloy catalysts towards the oxygen reduction reaction (ORR) as a function of the alloy overall composition and surface atomic distribution and compared to that on pure Pt surfaces. Reactivity is evaluated on the basis of the adsorption strength of oxygenated compounds which are intermediate species of the four-electron oxygen reduction reaction, separating the effect of the first electron-proton transfer from that of the three last electron-proton transfer steps. It is found that most homogeneous distribution PtxM catalysts thermodynamically favor the dissociation of adsorbed OOH in comparison with pure Platinum and adsorb strongly O and OH due to the strong oxyphilicity of the M elements. On the other hand, in all cases skin Platinum surfaces catalysts do not favor the dissociation of adsorbed OOH and do favor the reduction of M-O and M-OH with respect to Platinum. Considering the overall pathway of the reactions to catalyze the ORR most of the skin Platinum monolayer catalysts provide more negative free energy changes and should behave at least in a similar way than Platinum in following order: Pt3V (skin Pt) > Pt3Co (skin Pt) > Pt3Ni (skin Pt) > Pt > PtPd (skin) > Pt4Rh (skin Pt) > PtPd3 (skin ). In all cases, the reactivity is shown to be not only sensitive to the overall composition of the catalyst, but most importantly to the surface atomic distribution. Proposed electrochemical dissolution reactions of the catalyst atoms are also analyzed for the ORR catalysts, by computing the free energy changes of Platinum and bimetallic Pt-X (X: Co, Pd, Ni, and Rh) catalysts. It is found that Platinum is thermodynamically more stable than Pt-alloys in Pt3Co, Pt3Pd, Pt3Ni and Pt4Rh.

This dissertation investigates three topics in the field of multiple-bonded metal chemistry. The first topic concerns the synthetic and theoretical considerations of ditungsten formamidinates and guanidinates compounds. This work presents an enhanced synthetic path to the W2(hpp)4 molecule (Hhpp = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine). The reflux of W(CO)6 with Hhpp in o-dichlorobenzene at 200 oC produces W2(hpp)4Cl2 in a one-pot reaction in 92% yield. This compound is stable and easily stored for further use, and it can be efficiently reduced in a one-step reaction to the most easily ionized compound W2(hpp)4. This work also examines the electronic structure and geometry of the intermediates W2(µ-CO)2(µ- hpp)2(η2-hpp)2 and W2(hpp)4Cl2. The second topic concerns the theoretical investigation by DFT of the electronic structure of [Mo2] units bridged by oxamidate ligands or bridging hydride ions ([Mo2] = (Mo2(DArF)3, where DArF is the anion of a diarylformamidine). It is shown that the effect of the gauche conformation of the α oxamidate isomers is due to steric interactions, and that the planar β oxamidate isomers have an electronic structure similar to that of naphthalene when it is doubly oxidized. The [Mo2](µ-H)2[Mo2] compound shows interdimetal unit interactions between the δ orbitals of the two [Mo2] units. These interactions are theoretically predicted and experimentally observed by a decrease in the [Mo2]---[Mo2] distance with a one-electron oxidation of [Mo2](µ- H)2[Mo2]. The final topic concerns the magnetic and structural properties of two Ru2(DArF)4Cl compounds. The compounds with Ar = p-anisyl (para) and m-anisyl (meta) both show different temperature dependence of their molar magnetic susceptibility, χ. For the para compound, there is a Boltzmann distribution between a π*3 ground state and a δ*2π* upper state, and this is confirmed by a temperature dependence of the Ru-Ru bond length: 2.4471(5) àat 23 K and 2.3968(5) àat 300 K. For the meta compound, a δ*2π*configuration persists over the range of 23-300 K as shown by an invariant Ru-Ru bond length and its molar magnetic susceptibility.

Until recently, Taiwan elementary mathematics curriculum has been changing for several times. The aim of this study is to refer to various curriculum reforms, and focus on the way ¡§Number and Calculation Standards¡¨ changed in the history of reforms. The specific objectives of this study: to refer to one curriculum standards and its subsequent standards and do pair wise comparison. To achieve the above objectives, the investigator referred to 7 target versions of mathematics curriculum standards: 41, 51, 57, 64, 82, 89, 92 (R.O.C year). The comparison was done qualitatively, using historical research methodology. The main research findings are the differences in the above 6 pair wise comparisons. 1. The change from Year 41 to Year 51: In the Year 51, the part on Writing numbers in Chinese characters was de-emphasized. Emphasis was on Ordinal numbers, division thinking, mental arithmetic and written algorithm. The size of numbers reduced to 4-digits (due to a change in currency, 4 dollars to 1 New Taiwan dollar). 2. The change from Year 51 to 57: more focus on symbols, did not require the revision on what was learned in previous year. 3. The change from Year 57 to 64: de-emphasized on mental arithmetic and written calculation; emphasized on Inverses, multiplication/division on ¡§0¡¦ and ¡§1¡¨, ratio, approximation, negative numbers and use of electronic calculators. 4. The change from Year 64 to 82: no need to include negative numbers and abacus. Emphasized on two-step problems, number line, and reading multiplication tables. 5. The change from Year 82 to 89: de-emphasis on odd and even numbers; emphasis on realistic contexts, understanding vertical algorithm. 6. The change from Year 89 to 91: no need to use calculators to check working; emphasis on vertical algorithm, whole number calculations, and the connections of multiples/factors, rate/speed, and, fractions/decimals.

Thesis (Ph. D.)--Tampere University of Technology, 2002. / Includes bibliographical references. Also available on the World Wide Web.

Depletion calculations for nuclear reactors model the dynamic coupling between the material composition and neutron flux and help predict reactor performance and safety characteristics. In order to be trusted as reliable predictive tools and inputs to licensing and operational decisions, the simulations must include an accurate and holistic quantification of errors and uncertainties in its outputs. Uncertainty quantification is a formidable challenge in large, realistic reactor models because of the large number of unknowns and myriad sources of uncertainty and error. We present a framework for performing efficient uncertainty quantification in depletion problems using an adjoint approach, with emphasis on high-fidelity calculations using advanced massively parallel computing architectures. This approach calls for a solution to two systems of equations: (a) the forward, engineering system that models the reactor, and (b) the adjoint system, which is mathematically related to but different from the forward system. We use the solutions of these systems to produce sensitivity and error estimates at a cost that does not grow rapidly with the number of uncertain inputs. We present the framework in a general fashion and apply it to both the source-driven and k-eigenvalue forms of the depletion equations. We describe the implementation and verification of solvers for the forward and ad- joint equations in the PDT code, and we test the algorithms on realistic reactor analysis problems. We demonstrate a new approach for reducing the memory and I/O demands on the host machine, which can be overwhelming for typical adjoint algorithms. Our conclusion is that adjoint depletion calculations using full transport solutions are not only computationally tractable, they are the most attractive option for performing uncertainty quantification on high-fidelity reactor analysis problems.

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