A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. February 2015. / We explore the non-perturbative physics of giant gravitons in type IIB string theory on the AdS5 ⇥ S5 background in this thesis. The gauge theory dual is N = 4 super Yang-Mills theory with a U(N) gauge group. We diagonalise the one and two-loop dilatation operators acting on the restricted Schur polynomial basis. These operators are dual to a system of giant gravitons with strings attached. Hence, we present evidence for integrability in certain non-planar sectors of the gauge theory. In the second half of the thesis, we turn our focus to N = 4 super Yang-Mills theory with an SO(N) gauge group. In this case, the geometry of the dual gravity theory is AdS5 ⇥RP5. The non-planar physics of the SO(N) theory is distinct from that of the U(N) theory. To pursue the goal of searching for non-planar integrability in the SO(N) gauge theory, one might try to generalise the restricted Schur basis to the SO(N) case. We propose such a basis and evaluate their two-point functions exactly in the free theory. Further, we develop techniques to compute correlation functions of multi-trace operators involving two scalar fields exactly. Lastly, we extend these results to the theory with an Sp(N) gauge group.

Os moinhos de bolas são equipamentos presentes em plantas de mineração, sendo uma máquina importante no circuito de cominuição de minérios. Em função de inúmeros fatores como, por exemplo, projeto, fabricação, sobrecarga no equipamento, falta de manutenção e procedimentos de operação inadequados, são desenvolvidas descontinuidades nos componentes estruturais desse equipamento. Os componentes estruturais dos moinhos, basicamente, corpo, tampas e munhões, além do custo elevado, possuem prazos de fabricação que podem variar de dois a três anos dependendo da demanda do mercado. Portanto é cada vez mais necessário que as descontinuidades detectadas nesses componentes sejam corretamente avaliadas. Neste trabalho analisaram-se pela mecânica da fratura a criticalidade de descontinuidades, tais como trincas constatadas em um munhão de um moinho de bolas e compararam-se os valores teóricos de taxa de propagação (crescimento) dessas descontinuidades com valores reais obtidos por meio de inspeções periódicas realizadas neste componente. A nucleação das trincas foi causada por falta de lubrificação nos mancais do moinho, gerando esforços térmicos circunferenciais no munhão, em que a temperatura estimada do contato munhão e bucha atingiu a faixa de 100 °C a 150 °C. No período analisado, os resultados obtidos por meio da norma BS7910 mostraram-se mais próximos dos valores reais do que a norma ASME Seção XI, Apêndice A. O tamanho da trinca mais crítica foi aceito pelos critérios da norma BS7910 e aprovado apenas na condição de emergência da norma ASME Seção XI, Apêndice A. / The grinding ball mills are equipments present in mining plants, being important in the ore comminution circuits. Depending on numerous factors, such as, for example, design, manufacturing, overloads, poor maintenance and inadequate operating procedures, flaws are developed in the structural components of this equipment. The structural components of a mill, basically, shell, heads and trunnions, besides high costs, have lead times that might vary from two to three years, according to market demand. Therefore, it becomes increasingly necessary that any flaws in those components to be properly evaluated. This paper analyzed the fracture mechanics of the criticality of flaws, such as cracks observed in a ball mill trunnion and compared the theoretical values of growth rate of these defects with actual values obtained through periodic inspections performed in this component. The cracks nucleation was caused by lack of lubrication in the trunnion bearings, generating circumferential thermal stresses, thus the estimated temperature of the trunnion and bushing contact achieved the range 100 °C to 150 °C. During the analyzed period, the results obtained by the standard BS7910 proved to be closest to the actual values than the standard ASME, Section XI, Appendix A. The most critical crack size was accepted by the criteria of the BS7910 and approved only on emergency condition of ASME Section XI, Appendix A.

Planar maximally supersymmetric Yang-Mills theory (N = 4 SYM) is a special quantum fi eld theory. A few of its remarkable features are conformal symmetry at the quantum level, evidence of integrability and, moreover, it is a prime example of the AdS/CFT duality. Triggered by Witten's twistor string theory [1], the past 15 years have witnessed enormous progress in reformulating this theory to make as many of these special features manifest, from the choice of convenient variables to recursion relations that allowed new mathematical structures to appear, like the Grassmannian [2]. These methods are collectively referred to as on-shell methods. The ultimate hope is that, by understanding N = 4 SYM in depth, one can learn about other, more realistic quantum fi eld theories. The overarching theme of this thesis is the investigation of how on-shell methods can aid the computation of quantities other than scattering amplitudes. In this spirit we study form factors and correlation functions, said to be partially and completely off-shell quantities, respectively. More explicitly, we compute form factors of half-BPS operators up to two loops, and study the dilatation operator in the SO(6) and SU(2j3) sectors using techniques originally designed for amplitudes. A second part of the work is dedicated to the study of scattering amplitudes beyond the planar limit, an area of research which is still in its infancy, and not much is known about which special features of the planar theory survive in the non-planar regime. In this context, we generalise some aspects of the on-shell diagram formulation of Arkani-Hamed et al. [3] to take into account non-planar corrections.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Includes bibliographical references (p. 147-148). / This is a study of the ways in which the forms in landscapes - natural terrain adapted and inhabited - can serve as references in architectural design. As references for design, landscapes provide a richness of responses to local and evolutionary factors and a richness of associations which are central to our own identity and the identity of places or regions. In this thesis several perspectives on ways in which landscapes serve as references are analyzed. The landscape and surrounding context of each particular site importantly define its character and offer significant references for forms to be extended or generated. More broadly, landscapes can be viewed as sources for forms which can be transposed in multiple ways; the ultimate test of their value being whether they provide habitable, usable spaces. Landscapes can also be studied for the associations which they bring. These associations may explain feelings which we have about the quality and character of places . A series of principles for design are proposed. These principles reflect convergence amongst the several perspectives on how landscapes can serve as references and constitute a collection of suggestions for design. The principles are organized along a continuum of "forms", "processes of addition and change", and "associative qualities". Design studies for a site along the Neponset River at the south edge of Boston have been undertaken to aid in the development of the principles and illustrate their application. A mix of uses and building methods have been studied. The site for the studies is near the village center known as Lower Mills. The natural topography, the river's transition from narrow rapids to open estuary, and the historic collection of industrial buildings form a landscape rich in references and associations. / by James P. Batchelor. / M.Arch.

Orientador: Abraham Hirsz Zimerman / Banca: Waldyr Alves Rodrigues Junior / Banca: Cesar Augusto Linhares / Banca: Juan Alberto Mignaco / Banca: Ruben Aldrovandi / Doutor

For much of the early 1960s, House Ways and Means chairman Wilbur Mills represented the “One-Man Veto” on Medicare before eventually offering his reluctant support to the measure in 1964 and 1965. Ironically, this longtime opponent would be the one to suggest an expansion in the scope of the bill. Early proposals for Medicare only offered to cover hospital costs; Mills would call for physician costs to be covered, as well. The aim of this thesis is to show how Mills’s expansion of Medicare benefits in 1965 caused health care costs to skyrocket in the late 1960s, causing the fiscally conservative Mills to co-sponsor legislation for a single-payer national health insurance program along with Senator Edward Kennedy almost a decade later.

Abstract Production of pulp and paper from raw wood involves the washing of substantial quantities of highly coloured material from the wood pulp. Although most of this colour is trapped within the mill and the mills wastewater treatment system, discharge of coloured wastewater remains a problem of public concern. Lake Rotorua, New Zealand is filled with sediment consisting almost exclusively of diatoms. The most abundant species, Aulacoseira, has been shown to have very small pores, less than 200 nm, that could be very useful for the capture and holding of large organic molecules. Lake Rotorua is situated close to the two largest pulp and paper mills in New Zealand and may have to be dredged to solve a problem of eutrophication. Wastewaters generated at the Kinleith (Tokoroa) and Tasman (Kawerau) mills in the North island of New Zealand have been used to assess the characteristics of colour removal by Lake Rotorua diatoms. Vacuum filtration through the diatoms succeeded in removing colour but proved to be impractically slow as an industrial process. Addition of diatoms to wastewater streams in stirred experiments showed that significant adsorption took place. The majority of the colour was removed within 30 seconds of mixing. The efficiency of colour removal was found to vary between wastewater streams within the mills. The pH dependency of this removal was tested and found to be most effective in a pH range of 3.6 to 5. Attempts to reuse the diatoms showed that chemical backwash regimes were more effective than calcination. This study concluded that surface silanols were likely to be the principle agent in forming coagulants with the colour material and were subsequently trapped on the diatom surfaces, but more importantly within the pores.

Polymorphism and crystallinity are now recognised as important issues in drug development. This is shown by the increased amount of research in this area over recent years. In pharmaceutical development milling is an important unit operation for size reduction to improve powder handling, processing and dissolution rate. The aim of this thesis was to investigate the effect of ball milling (and cryo-milling) on the solid state properties, including amorphous drug formation, of pharmaceutical solids. Milling was carried out using an oscillatory ball mill (Mixer Mill MM301, Retsch GmbH & Co., Germany). In cryo-milling the milling jars were immersed in liquid nitrogen for three min before milling. XRPD was used as the main technique to evaluate the milled samples. Ranitidine hydrochloride (RAN) and indomethacin (INDO) were the model drugs used in this study. It was found that upon milling, RAN form 1 converts to RAN form 2 via an amorphous phase. A faster amorphization rate was observed when the crystalline samples were cryo-milled. Amorphous ranitidine hydrochloride was characterized to have a glass transition (T[g]) range of 13 to 30 �C and a crystallization exotherm (T[c]) between 30 and 65 �C. Conversion was found to occur faster when the temperature of the solid powder was greater than the T[c]. Under various storage conditions, similarly, crystallization of the amorphous phase mainly led to RAN form 2. However, some form 1 and amorphous phase was also detected on the XRPD diffractograms. Using partial least squares regression, the amount of solid form components in the ternary RAN mixtures were successfully quantified. RAN form 2 did not convert to form 1 under any milling (including cryo-milling) or storage conditions used in this study. Overall, RAN form 2 was found to be the thermodynamically stable form and the two (RAN) polymorphs are likely to be a monotropic pair. In a co-milling study of INDO and RAN, the two crystalline drugs were successfully converted into a single amorphous phase after 60 min of co-milling in a cold room (4 �C). The T[g] range (26-44 �C) was also characterized for these mixtures. DRIFTS spectra of the co-milled amorphous samples indicated an interaction had occurred between the carboxylic acid carbonyl (HO-C=O) and benzonyl amide (NC=O) of the INDO molecule with the aci-nitro (C=NO₂) of RAN. Depending on the ratio of INDO to RAN, in general, the amorphous mixtures were stable at 4 �C after 30 days of storage. Crystallization was faster when the binary mixtures were stored at higher temperature or contained higher amounts of RAN in the mixture. Although XRPD and DRIFTS suggested an interaction between the two drugs, co-crystal formation was not observed between INDO and RAN. Ball milling can be used to produce amorphous drug. The rate and extent of amorphization is dependent on the milling conditions. A faster rate of amorphization was observed when the crystalline drugs were cryo-milled. Amorphous drug formation can be made either alone or in combination with another crystalline drug. Amorphization could offer a significant improvement on the dissolution profile and the bioavailability of the poorly water soluble drug - indomethacin. Furthermore, ball milling can also be used to produce a homogenous mix between solids. The �goodmix� effect can be used for seed-induced crystallization or, when the XRPD or Raman data were combined with partial least squares regression, to create a reliable calibration model for quantitative analysis.

Thesis (Ph. D.)--University of Chicago, Dept. of Physics, June 1999. / Includes bibliographical references. Also available on the Internet.