Sample records for areas phd thesis

  1. PhD Thesis: Functional Textiles in Hospital Interiors

    Mogensen, Jeppe Emil

    The PhD thesis explores the possibilities and design qualities of using functional textiles in the interior of hospital environments, and is the result of a three-year collaboration between Aalborg University, Department of Civil Engineering, and VIA University College, VIA Design. The thesis...... main design qualities that may improve the patients’ experience of the hospital interior, and in the experimental studies these aesthetic quali- ties are contextualised in empirical studies conducted at two Danish hospitals. Through these different studies, the PhD thesis addresses the technical and...

  2. Instructable autonomous agents. Ph.D. Thesis

    Huffman, Scott Bradley


    In contrast to current intelligent systems, which must be laboriously programmed for each task they are meant to perform, instructable agents can be taught new tasks and associated knowledge. This thesis presents a general theory of learning from tutorial instruction and its use to produce an instructable agent. Tutorial instruction is a particularly powerful form of instruction, because it allows the instructor to communicate whatever kind of knowledge a student needs at whatever point it is needed. To exploit this broad flexibility, however, a tutorable agent must support a full range of interaction with its instructor to learn a full range of knowledge. Thus, unlike most machine learning tasks, which target deep learning of a single kind of knowledge from a single kind of input, tutorability requires a breadth of learning from a broad range of instructional interactions. The theory of learning from tutorial instruction presented here has two parts. First, a computational model of an intelligent agent, the problem space computational model, indicates the types of knowledge that determine an agent's performance, and thus, that should be acquirable via instruction. Second, a learning technique, called situated explanation specifies how the agent learns general knowledge from instruction. The theory is embodied by an implemented agent, Instructo-Soar, built within the Soar architecture. Instructo-Soar is able to learn hierarchies of completely new tasks, to extend task knowledge to apply in new situations, and in fact to acquire every type of knowledge it uses during task performance - control knowledge, knowledge of operators' effects, state inferences, etc. - from interactive natural language instructions. This variety of learning occurs by applying the situated explanation technique to a variety of instructional interactions involving a variety of types of instructions (commands, statements, conditionals, etc.). By taking seriously the requirements of flexible

  3. The Virtual Observatory Powered PhD Thesis

    Zolotukhin, Ivan


    The Virtual Observatory has reached sufficient maturity for its routine scientific exploitation by astronomers. To prove this statement, here I present a brief description of the complete VO-powered PhD thesis entitled "Galactic and extragalactic research with modern surveys and the Virtual Observatory" comprising 4 science cases covering various aspects of astrophysical research. These comprize: (1) homogeneous search and measurement of main physical parameters of Galactic open star clusters in huge multi-band photometric surveys; (2) study of optical-to-NIR galaxy colors using a large homogeneous dataset including spectroscopy and photometry from SDSS and UKIDSS; (3) study of faint low-mass X-ray binary population in modern observational archives; (4) search for optical counterparts of unidentified X-ray objects with large positional uncertainties in the Galactic Plane. All these projects make heavy use of the VO technologies and tools and would not be achievable without them. So refereed papers published i...

  4. MATLAB simulation software used for the PhD thesis "Acquisition of Multi-Band Signals via Compressed Sensing


    MATLAB simulation software used for the PhD thesis "Acquisition of Multi-Band Signals via Compressed Sensing......MATLAB simulation software used for the PhD thesis "Acquisition of Multi-Band Signals via Compressed Sensing...

  5. Motivation in medical students: a PhD thesis report

    Kusurkar, Rashmi


    The aims of this thesis were to gather insights and investigate the factors influencing, outcomes and applications of medical students' motivation. This thesis consists of three literature reviews, four research papers and two application papers. Two research studies investigated the relationships of student motivation with study strategy, effort and academic performance through structural equation modelling and cluster analysis. The relationships of age, maturity, gender and educational back...

  6. Motivation in medical students: a PhD thesis report.

    Kusurkar, Rashmi


    The aims of this thesis were to gather insights and investigate the factors influencing, outcomes and applications of medical students' motivation. This thesis consists of three literature reviews, four research papers and two application papers. Two research studies investigated the relationships of student motivation with study strategy, effort and academic performance through structural equation modelling and cluster analysis. The relationships of age, maturity, gender and educational background with motivation were investigated through multiple regression analysis. The results of this thesis were 1. Developments in medical education appear to have undervalued student motivation. 2. Motivation is an independent variable in medical education; intrinsic motivation is significantly associated with deep study strategy, high study effort and good academic performance. 3. Motivation is a dependent variable in medical education and is significantly affected by age, maturity, gender, educational background; intrinsic motivation is enhanced by providing students with autonomy, feedback and emotional support. 4. Strength of motivation for medical school can be reliably measured by Strength of Motivation for Medical School questionnaire. The conclusion of this thesis was that it is important to give consideration to motivation in medical education because intrinsic motivation leads to better learning and performance and it can be enhanced through giving students autonomy in learning, feedback about competence and emotional support. PMID:23316471

  7. Topics in vacuum decay (Ph.D Thesis)

    Masoumi, Ali


    If a theory has more than one classically stable vacuum, quantum tunneling and thermal jumps make the transition between the vacua possible. The transition happens through a first order phase transition started by nucleation of a bubble of the new vacuum. The outward pressure of the truer vacuum makes the bubble expand and consequently eat away more of the old phase. In the presence of gravity this phenomenon gets more complicated and meanwhile more interesting. It can potentially have important cosmological consequences. Some aspects of this decay are studied in this thesis. Solutions with different symmetry than the generically used O(4) symmetry are studied and their actions calculated. Vacuum decay in a spatial vector field is studied and novel features like kinky domain walls are presented. The question of stability of vacua in a landscape of potentials is studied and the possible instability in large dimension of fields is shown. Finally a compactification of the Einstein-Maxwell theory is studied which...

  8. Nozzle Flow with Vibrational Nonequilibrium. Ph.D. Thesis

    Landry, John Gary


    Flow of nitrogen gas through a converging-diverging nozzle is simulated. The flow is modeled using the Navier-Stokes equations that have been modified for vibrational nonequilibrium. The energy equation is replaced by two equations. One equation accounts for energy effects due to the translational and rotational degrees of freedom, and the other accounts for the affects due to the vibrational degree of freedom. The energy equations are coupled by a relaxation time which measures the time required for the vibrational energy component to equilibrate with the translational and rotational energy components. An improved relaxation time is used in this thesis. The equations are solved numerically using the Steger-Warming flux vector splitting method and the Implicit MacCormack method. The results show that uniform flow is produced outside of the boundary layer. Nonequilibrium exists in both the converging and diverging nozzle sections. The boundary layer region is characterized by a marked increase in translational-rotational temperature. The vibrational temperature remains frozen downstream of the nozzle, except in the boundary layer.

  9. Paleomagnetism of the Mesozoic in Alaska. Ph.D. Thesis

    Packer, D. R.


    Over 400 oriented cores of Permian, Triassic, Jurassic, and Cretaceous sedimentary and igneous rocks were collected from 34 sites at 10 areas throughout southern Alaska. After magnetic cleaning in successively higher alternating fields 179 samples were considered to be stable and to give statistically consistent results within each site and age group. Due to the lack of a sufficient number of stable samples, the results from Permian, Triassic, and Cretaceous rocks were inconclusive. The nine remaining Jurassic sites represent 100 samples from three general areas in southern Alaska. The southern Alaskan Jurassic paleomagnetic pole is significantly different from the North American Jurassic pole. This suggests that since the Jurassic, southern Alaska must have moved approximately 18 degrees north and rotated 52 degrees clockwise to reach its present position. Tectonic interpretation of these results give a possible explanation for many of the geologic features observed in southern Alaska.

  10. The Jade File System. Ph.D. Thesis

    Rao, Herman Chung-Hwa


    File systems have long been the most important and most widely used form of shared permanent storage. File systems in traditional time-sharing systems, such as Unix, support a coherent sharing model for multiple users. Distributed file systems implement this sharing model in local area networks. However, most distributed file systems fail to scale from local area networks to an internet. Four characteristics of scalability were recognized: size, wide area, autonomy, and heterogeneity. Owing to size and wide area, techniques such as broadcasting, central control, and central resources, which are widely adopted by local area network file systems, are not adequate for an internet file system. An internet file system must also support the notion of autonomy because an internet is made up by a collection of independent organizations. Finally, heterogeneity is the nature of an internet file system, not only because of its size, but also because of the autonomy of the organizations in an internet. The Jade File System, which provides a uniform way to name and access files in the internet environment, is presented. Jade is a logical system that integrates a heterogeneous collection of existing file systems, where heterogeneous means that the underlying file systems support different file access protocols. Because of autonomy, Jade is designed under the restriction that the underlying file systems may not be modified. In order to avoid the complexity of maintaining an internet-wide, global name space, Jade permits each user to define a private name space. In Jade's design, we pay careful attention to avoiding unnecessary network messages between clients and file servers in order to achieve acceptable performance. Jade's name space supports two novel features: (1) it allows multiple file systems to be mounted under one direction; and (2) it permits one logical name space to mount other logical name spaces. A prototype of Jade was implemented to examine and validate its

  11. Top tips for PhD thesis examination: nurse clinicians, researchers and novices.

    Cleary, Michelle; Horsfall, Jan; Hunt, Glenn E


    Interestingly, there are very few guidelines in the literature to assist novice nurse PhD examiners. In this paper, we aim to provide information to nurses, researchers or early career academics who have little experience in assessing a university thesis. The article provides background information about recent changes in the university sector; overviews some research on experienced examiners views; presents factors that differentiate between high and low quality PhD theses; and outlines some pointers that may be useful when marking at the doctoral level. PMID:21903305

  12. Multipole gas thruster design. Ph.D. Thesis

    Isaacson, G. C.


    The development of a low field strength multipole thruster operating on both argon and xenon is described. Experimental results were obtained with a 15-cm diameter multipole thruster and are presented for a wide range of discharge-chamber configurations. Minimum discharge losses were 300-350 eV/ion for argon and 200-250 eV/ion for xenon. Ion beam flatness parameters in the plane of the accelerator grid ranged from 0.85 to 0.93 for both propellants. Thruster performance is correlated for a range of ion chamber sizes and operating conditions as well as propellant type and accelerator system open area. A 30-cm diameter ion source designed and built using the procedure and theory presented here-in is shown capable of low discharge losses and flat ion-beam profiles without optimization. This indicates that by using the low field strength multipole design, as well as general performance correlation information provided herein, it should be possible to rapidly translate initial performance specifications into easily fabricated, high performance prototypes.

  13. "Essays on International Business Cycles", PhD thesis, Economics Department, University of Chicago, 1991.

    Kollmann, Robert


    PhD dissertation, 1991, Economics Department, University of Chicago. (Thesis committee: Michael Woodford, advisor; José Scheinkman; John Huizinga.) Models of the international economy which assume complete asset markets predict that consumption co-moves closely in different countries as this structure of asset markets allows agents in different countries to 'pool' the country-specific risks which they face (see Scheinkman (1984), Leme (1984)). Examples in this class of models include the...

  14. Synthesis of the PhD thesis "Anti-money laundering and counter terrorism financing management"

    Camelia Popa


    As a whole, this PhD thesis follows three research lines, namely: (1) the conceptual line - concerns the definition of the money laundering and terrorism financing phenomenon, the processes, mechanisms, stages and instruments of the laundering of illegally obtained fund; (2) the estimative line aimed at measuring the size of money laundering phenomenon, the economic, social and security effects and consequences; (3) the line of an awareness of the need to prevent and fight against the effects...

  15. Synthesis of the PhD thesis "Anti-money laundering and counter terrorism financing management"

    Camelia Popa


    Full Text Available As a whole, this PhD thesis follows three research lines, namely: (1 the conceptual line - concerns the definition of the money laundering and terrorism financing phenomenon, the processes, mechanisms, stages and instruments of the laundering of illegally obtained fund; (2 the estimative line aimed at measuring the size of money laundering phenomenon, the economic, social and security effects and consequences; (3 the line of an awareness of the need to prevent and fight against the effects arising from money laundering processes, the national and international efforts taken until present nation- and worldwide and the future measures required to diminish the consequences of this scourge.

  16. Management of Stress and Anxiety Among PhD Students During Thesis Writing: A Qualitative Study.

    Bazrafkan, Leila; Shokrpour, Nasrin; Yousefi, Alireza; Yamani, Nikoo


    Today, postgraduate students experience a variety of stresses and anxiety in different situations of academic cycle. Stress and anxiety have been defined as a syndrome shown by emotional exhaustion and reduced personal goal achievement. This article addresses the causes and different strategies of coping with this phenomena by PhD students at Iranian Universities of Medical Sciences. The study was conducted by a qualitative method using conventional content analysis approach. Through purposive sampling, 16 postgraduate medical sciences PhD students were selected on the basis of theoretical sampling. Data were gathered through semistructured interviews and field observations. Six hundred fifty-four initial codes were summarized and classified into 4 main categories and 11 subcategories on the thematic coding stage dependent on conceptual similarities and differences. The obtained codes were categorized under 4 themes including "thesis as a major source of stress," "supervisor relationship," "socioeconomic problem," and "coping with stress and anxiety." It was concluded that PhD students experience stress and anxiety from a variety of sources and apply different methods of coping in effective and ineffective ways. Purposeful supervision and guidance can reduce the cause of stress and anxiety; in addition, coping strategy must be in a thoughtful approach, as recommended in this study. PMID:27455365

  17. Nitrogen Removal in Riparian Areas. PhD thesis

    Blicher-Mathiesen, G.

    Formålet med Ph.D.-studiet er at beskrive og måle kvælstoffjernelse i vådområder. En væsentlig del af formålet har været at udvikle en ny metode til måling af kvælstoffjernelse i vådområder. Rapporten indeholder seks engelsksprogede artikler, som er på vej til at blive, eller er publiceret, i int...

  18. 博士论文选题研究%Research on Topic Selection of Ph.D. Thesis

    夏庆霖; 赵鹏大


    Through statistically analyzing the topics of 102 Ph.D. thesis, the article advances the mare principles ror tnesis topic selection, such as frontier, application, innovation, challenge and feasibility. Finally, a new idea is proposed that thesis topic selection will be written into the guide of recruit students as an important reform item.%本文通过对102篇博士论文选题的统计分析,提出博士论文选题应遵循前沿性、应用性、创新性、挑战性和可行性五大原则,以及以选题为指南的博士生招生改革思路。

  19. Spanish production of PhD Thesis in the field of guidance on TESEO database (2001-2012

    Ferreira-Villa, Camino


    Full Text Available The objective of this research is to analyse the scientific production in PhD Thesis about guidance in Spain from 2001 to 2012. The data have been recollected on the TESEO database belonging to the Ministry of Education, Culture and Sport. It has realized a content analysis of the titles, keywords and abstracts and it has assessed of them their productivity, the general and methodological features and the subjects that have been studied. It has been obtained ninety PhD Thesis in relation to the field of guidance over the last ten years that have studied mainly curriculum and career development. El objetivo de este estudio es analizar la producción científica en Tesis Doctorales sobre orientación en España entre 2001 y 2012. Los datos han sido recogidos a través de la Base de datos TESEO del Ministerio de Educación, Cultura y Deporte. Se ha realizado un análisis de contenido de los títulos, descriptores y resúmenes, valorando la productividad del área, las principales características generales y metodológicas y las temáticas estudiadas. Se han obtenido noventa Tesis Doctorales relacionadas con el ámbito de la orientación en los últimos diez años que han estudiado principalmente aspectos sobre el currículum y el desarrollo vocacional.

  20. The Experienced Meaning of Working with a PhD Thesis

    Stubb, Jenni; Pyhalto, Kirsi; Lonka, Kirsti


    There is a variation in terms of how researchers perceive the nature of research work. Previous research has mainly looked at the members of academia who already have established themselves in the scholarly community. We aimed at exploring the ways in which doctoral students perceived their thesis project and further, the relations of such…

  1. Reading in Preparation for Writing a PhD Thesis: Case Studies of Experiences

    Kwan, Becky S. C.


    The paper presents stories of how a group of doctoral students chose the key disciplinary literature that they read in preparation for their thesis-undertaking (RT). The stories were analyzed in light of current understanding of literature reviewing as a situated practice and theory of doctoral education as socio-cognitive apprenticeship. As the…

  2. A numerical study of fundamental shock noise mechanisms. Ph.D. Thesis - Cornell Univ.

    Meadows, Kristine R.


    The results of this thesis demonstrate that direct numerical simulation can predict sound generation in unsteady aerodynamic flows containing shock waves. Shock waves can be significant sources of sound in high speed jet flows, on helicopter blades, and in supersonic combustion inlets. Direct computation of sound permits the prediction of noise levels in the preliminary design stage and can be used as a tool to focus experimental studies, thereby reducing cost and increasing the probability of a successfully quiet product in less time. This thesis reveals and investigates two mechanisms fundamental to sound generation by shocked flows: shock motion and shock deformation. Shock motion is modeled by the interaction of a sound wave with a shock. During the interaction, the shock wave begins to move and the sound pressure is amplified as the wave passes through the shock. The numerical approach presented in this thesis is validated by the comparison of results obtained in a quasi-one dimensional simulation with linear theory. Analysis of the perturbation energy demonstrated for the first time that acoustic energy is generated by the interaction. Shock deformation is investigated by the numerical simulation of a ring vortex interacting with a shock. This interaction models the passage of turbulent structures through the shock wave. The simulation demonstrates that both acoustic waves and contact surfaces are generated downstream during the interaction. Analysis demonstrates that the acoustic wave spreads cylindrically, that the sound intensity is highly directional, and that the sound pressure level increases significantly with increasing shock strength. The effect of shock strength on sound pressure level is consistent with experimental observations of shock noise, indicating that the interaction of a ring vortex with a shock wave correctly models a dominant mechanism of shock noise generation.

  3. Radiation and scattering from cylindrically conformal printed antennas. Ph.D. Thesis Final Report

    Kempel, Leo C.; Volakis, John L.


    Microstrip patch antennas offer considerable advantages in terms of weight, aerodynamic drag, cost, flexibility, and observables over more conventional protruding antennas. These flat patch antennas were first proposed over thirty years ago by Deschamps in the United States and Gutton and Baisinot in France. Such antennas have been analyzed and developed for planar as well as curved platforms. However, the methods used in these designs employ gross approximations, suffer from extreme computational burden, or require expensive physical experiments. The goal of this thesis is to develop accurate and efficient numerical modeling techniques which represent actual antenna structures mounted on curved surfaces with a high degree of fidelity. In this thesis, the finite element method is extended to cavity-backed conformal antenna arrays embedded in a circular, metallic, infinite cylinder. Both the boundary integral and absorbing boundary mesh closure conditions will be used for terminating the mesh. These two approaches will be contrasted and used to study the scattering and radiation behavior of several useful antenna configurations. An important feature of this study will be to examine the effect of curvature and cavity size on the scattering and radiation properties of wraparound conformal antenna arrays.

  4. Microscopic-macroscopic models for fission of extreme mass asymmetry. Resume of Ph.D thesis

    This is an extended abstract of the Ph. D. thesis devoted to the microscopic-macroscopic nuclear models able to describe the fission processes with high mass asymmetry. The chapter one presents the pertinent research on nuclear cluster emission, both theoretical and experimental. The chapter two presents a new nuclear shape parametrization with three degrees of freedom: elongation, necking, and mass asymmetry. General features of three dimensional potential barrier behaviour are analysed for the case of high mass asymmetry for different neck geometries. The chapter number three gives the computing methods of the shell corrections adequate for the case of high mass asymmetries. A new extension of the two-center harmonic approach to the single-particle shell model in the case of high asymmetry is given. The fourth chapter is devoted to the nuclear dynamics of the decay processes in a broad range of mass asymmetry to include under the same formalism the cold fission, heavy-ion emission and alpha decay. Two original methods to obtain the likeliest fission pattern with the essential features of the three subdue processes are finally described. The methods developed in this thesis are illustrated on the case of 234 U fission with 28 Mg as cluster emission and with 100 Zr as light fission fragment. (M.I.C.). 9 Figs., 48 Refs

  5. Contributions to the study of nuclear fragmentation in nucleus-nucleus interactions. Resume of Ph.D thesis

    The subject of Ph.D thesis is devoted to the study of high-energy nuclear fragmentation of He, C, Ne, Si, O nuclei resulting from the collisions of accelerated nuclei with target nuclei constituent of thick nuclear emulsions at primary momenta around 4.5 A GeV/c. The nuclear emulsions were irradiated at JINR-Synchrophasotron in Dubna, Russia. Geometrical measurements were performed with a semi-automated device mounted on a KSM-type microscope and the charges were determined by an original photometric method. From the analysis of topological diagrams a new class of decay events were evidenced in which the primary nucleus is fragmented in nuclei with electrical charge smaller or equal to two units. From the behaviour of the parameters characterizing these events the conclusions was drown that the fragmentation mechanism is different from the ones responsible for other decay channels. The most significant result thoroughly discussed in this thesis is that the high energy tail in the transverse momentum distribution is due to a source different from that explaining the main body of the distribution. (author) 9 Figs., 8 Tabs., 36 Refs

  6. Transport phenomena in high Tc superconductors. Resume of Ph.D thesis

    This is an extended abstract of the Ph. D. thesis devoted to the transport phenomena in high-Tc superconductors. There are three chapters. The first chapter presents an overview of the essential theoretical aspects concerning the vortex dynamics particularly in ceramic superconductors. The chapter two gives a description of the preparation methods of superconductor samples used by the author as well as the measurement devices for volt-ampere characteristics and the associated electronic circuitry. In the third chapter there are presented the experimental data obtained from different samples prepared in different temperature and magnetic field conditions. The obtained results are finally interpreted in the frame of existent or original models. (M.I.C.). 31 Refs

  7. Preparation and characterization of ferroelectric thin layers for IR detection. Resume of Ph.D thesis

    The thesis is studying the ferroelectric thin films, stressing their pyroelectric properties (for applications in the IR detection). In the beginning there are presented the deposition methods used for obtaining ferroelectric thin films and some of the most important applications. An entire chapter is dedicated to the thermodynamic theory of ferroelectrics, the general presentation of a new deposition method (the sol-gel method) and to a short presentation of the characterization methods (structural and electrical) of the ferroelectric thin films. The structural characterization was made by RX diffraction and the electrical characterization was made by measuring the I-V and C-V characteristics, the polarization and the photoelectric parameters. It is described the deposition of Pb Ti O3 thin films using the sol-gel method. A buffer thin film of Ba Pb O3 - RF sputtered - was used for growing the Pb Ti O3 film because of its perovskivic structure. It was studied the electrical conduction in Ba Pb O3 films. Very important is the study of the photoelectric effect in Pb Ti O3/Si and Pb S/Pb Ti O3/Si heterostructures. In the last part an original pyroelectric detector realized by using a bimorph structure is proposed. On a Pt/Ti/Si O3/Si substrate by sol-gel method a bimorph system is deposited which consists in a basic film of PLZT 2/65/35 and a frontal film of PLZT 8/65/35. The sensitive element was defined by photolithography. The detailed discussion on the obtaining of the heterostructures and the realization of the detector are presented in the final part of this thesis. This resume contains a section describing the preparation of ferroelectric thin layers by the sol-gel method, a section describing the obtained results and the pertinent discussion and conclusions. (author) 20 figs., 1 tab., 27 refs

  8. Toroidal collective motions in atomic nuclei. Resume of Ph.D thesis

    Short communication. The thesis treats one of the types of collective motion. Using the multipole parametrization for the charge and current, introduced by Dubovik and Cheshkov, the toroidal multipoles are extracted from the expansion of the transverse part of the current density. This new class of electromagnetic multipoles is associated with poloidal flows from a macroscopic point of view. In the frame of Nuclear Fluid Dynamics, a model which portrays the nuclear matter as a quantum elastic body, the torus-like motions and their associated energies are computed using the thirteen moment approximation. Such excitations correspond to the Hill vortex known from classical hydrodynamics. There are also calculated the nonvanishing contributions of transverse electric form factors and differential cross sections in the electroexcitation of these collective modes which are purely toroidal. Next we study the spin-dependent collective excitations with toroidal electromagnetic structure by means of the Generalized Goldhaber-Teller model with emphasis on the 1- spin-flip mode and its excitation in spherical nuclei by inelastic electron scattering. In the second part of the thesis we discuss the importance of toroidal contributions in the inclusive electron scattering (e, e') and exclusive coincidence electron scattering (e, e'γ). In order to extract the toroidal multiple we use the back scattering angles in the first mentioned reaction, and the separation of the longitudinal/transverse interference, in the second case. The introduction of a quantity which accounts for the deviations from the Siegert theorem shows the importance of toroidal quadrupole transitions at high-momentum transfer. Another important result concerns the dependence of the intensity of toroidal effects on the nuclear vorticity. (Author) 15 Figs., 1 Tab., 32 Refs

  9. The intrinsic bispectrum of the Cosmic Microwave Background (Ph.D. thesis)

    Pettinari, Guido Walter


    [Abridged version] A huge theoretical and experimental effort is being made by cosmologists and particle physicists to gain insight of the mechanism of generation of the primordial cosmological fluctuations, which remains still largely unknown. The bispectrum of the cosmic microwave background (CMB) has been recognised as a powerful probe of this mechanism, as it is sensitive to the non-Gaussian features in the seed fluctuations. To access this information, however, it is crucial to model the non-linear evolution of the CMB between the formation of the initial fluctuations and its observation, which results in the emergence of an intrinsic bispectrum. In this thesis we quantify the intrinsic bispectrum and compute the bias it induces on the primordial signal. To do so, we develop $\\text{SONG}$, an efficient code for solving the second-order Einstein-Boltzmann equations, and use it to estimate the CMB non-Gaussianity arising from the non-linear evolution of density perturbations. The full calculation involves ...

  10. Structure of neutron-deficient nuclei by gamma spectroscopy. Resume of Ph.D thesis

    This is an extended abstract of the Ph. D. thesis devoted to the experimental study by in-beam gamma spectroscopy of the neutron-deficient nuclei 111 Sb and 146 Nd. The experimental investigation of these nuclei implied the following measurements: 1. in-beam activations; 2. cross reactions; 3. excitation functions; 4. charged-particle - gamma; 5. neutron - gamma coincidences; 6. γ-γ coincidences; 7. lifetime determinations; 8. gated-angular distributions 9. angular correlations. Original contributions concerning lifetime determination through the time centroid shift method, interpretation of double angular correlations of gamma rays emitted from oriented sources and a quasi-complete program package for processing and interpretation of in-beam gamma spectroscopy data are given. The nuclear data and shape coexistence in the 111 Sb nucleus are reported for the first time. The nuclear level scheme of 146 Nd was greatly extended, reaching levels as high as E ∼ 7.5 MeV, and Jπ = (22+). Also in the case of this nucleus the coexistence of mirror symmetric and asymmetric states was evidenced. The data were interpreted both in the frame of deformed mean field model and IBA model. (M.I.C.). 5 Figs., 3 Tabs., 35 Refs

  11. Investigation of finite element: ABC methods for electromagnetic field simulation. Ph.D. Thesis

    Chatterjee, A.; Volakis, John L.; Nguyen, J.


    The mechanics of wave propagation in the presence of obstacles is of great interest in many branches of engineering and applied mathematics like electromagnetics, fluid dynamics, geophysics, seismology, etc. Such problems can be broadly classified into two categories: the bounded domain or the closed problem and the unbounded domain or the open problem. Analytical techniques have been derived for the simpler problems; however, the need to model complicated geometrical features, complex material coatings and fillings, and to adapt the model to changing design parameters have inevitably tilted the balance in favor of numerical techniques. The modeling of closed problems presents difficulties primarily in proper meshing of the interior region. However, problems in unbounded domains pose a unique challenge to computation, since the exterior region is inappropriate for direct implementation of numerical techniques. A large number of solutions have been proposed but only a few have stood the test of time and experiment. The goal of this thesis is to develop an efficient and reliable partial differential equation technique to model large three dimensional scattering problems in electromagnetics.

  12. Robust control design with real parameter uncertainty using absolute stability theory. Ph.D. Thesis

    How, Jonathan P.; Hall, Steven R.


    The purpose of this thesis is to investigate an extension of mu theory for robust control design by considering systems with linear and nonlinear real parameter uncertainties. In the process, explicit connections are made between mixed mu and absolute stability theory. In particular, it is shown that the upper bounds for mixed mu are a generalization of results from absolute stability theory. Both state space and frequency domain criteria are developed for several nonlinearities and stability multipliers using the wealth of literature on absolute stability theory and the concepts of supply rates and storage functions. The state space conditions are expressed in terms of Riccati equations and parameter-dependent Lyapunov functions. For controller synthesis, these stability conditions are used to form an overbound of the H2 performance objective. A geometric interpretation of the equivalent frequency domain criteria in terms of off-axis circles clarifies the important role of the multiplier and shows that both the magnitude and phase of the uncertainty are considered. A numerical algorithm is developed to design robust controllers that minimize the bound on an H2 cost functional and satisfy an analysis test based on the Popov stability multiplier. The controller and multiplier coefficients are optimized simultaneously, which avoids the iteration and curve-fitting procedures required by the D-K procedure of mu synthesis. Several benchmark problems and experiments on the Middeck Active Control Experiment at M.I.T. demonstrate that these controllers achieve good robust performance and guaranteed stability bounds.

  13. Method for optimizing resource allocation in a government organization. Ph.D. Thesis

    Afarin, James


    The managers in Federal agencies are challenged to control the extensive activities in government and still provide high-quality products and services to the American taxpayers. Considering today's complex social and economic environment and the $3.8 billion daily cost of operating the Federal Government, it is evident that there is a need to develop decision-making tools for accurate resource allocation and total quality management. The goal of this thesis is to provide a methodical process that will aid managers in Federal Government to make budgetary decisions based on the cost of services, the agency's objectives, and the customers' perception of the agency's product. A general resource allocation procedure was developed in this study that can be applied to any government organization. A government organization, hereafter the 'organization,' is assumed to be a multidivision enterprise. This procedure was applied to a small organization for the proof of the concept. This organization is the Technical Services Directorate (TSD) at the NASA Lewis Research Center in Cleveland, Ohio. As part of the procedure, a nonlinear programming model was developed to account for the resources of the organization, the outputs produced by the organization, the decision-maker's views, and the customers' satisfaction with the organization. The information on the resources of the organization was acquired from current budget levels of the organization and the human resources assigned to the divisions. The outputs of the organization were defined and measured by identifying metrics that assess the outputs, the most challenging task in this study. The decision-maker's views are represented in the model as weights assigned to the various outputs and were quantified by using the analytic hierarchy process. The customer's opinions regarding the outputs of the organization were collected through questionnaires that were designed for each division individually. Following the philosophy of

  14. Methods and devices for characterization of neutron field in controlled nuclear fusion installations. Resume of Ph.D thesis

    The abstract presents the essential features of the Ph.D. thesis which is dealing with the development of advanced methods and devices for characterization of neutron emission in controlled nuclear fusion systems. This work presents the author's contribution to neutron diagnosis in fusion systems and especially in investigation and understanding of fusion mechanisms in dense Z-pinch installations in their most preferment variant plasma focus, aiming to optimization of neutron production and applications. The work is structured in 6 chapters and 4 appendices. The first chapter presents the numerical and analytical models for the main characteristics of neutron emission in fusion systems. To extract quantitative information on the distribution function of reacting deuterons from neutron measurements analytical expressions for flux anisotropy and energy spectrum of the fusion neutrons emitted in Z-pinch installations were derived. The second chapter introduces the main calibration method of total neutron yield in pulsed fusion system. The conclusions of this study were used for selecting the optimal method of experimental determination of neutron yield in plasma focus installations operating in the laboratory of plasma physics and nuclear fusion of the Institute for Physics and Technology of Radiation Devices, Bucharest and in the Focalized Plasma Group in the Institute of Experimental Physics of the Heinrich-Heine University, Dusseldorf. The third chapter describes the theoretical principles in the spectroscopy of fusion neutrons. The fourth chapter is entirely dedicated to the characterization of neutron emission in the focalized plasma installation SPEED-2 of the University of Dusseldorf. In the fifth chapter there are introduced and applied original methods for determination of energy and angular characteristics of the distribution function of reactant deuterons in focalized plasma. In the sixth chapter it is developed an original concept of collimation and

  15. Factors controlling fluxes of volatile sulfur compounds in Sphagnum peatlands. Ph.D. Thesis

    Demello, William Zamboni


    Exchange of DMS and OCS between the surface of Sphagnum peatlands and the atmosphere were measured with dynamic (S-free sweep air) and static enclosures. DMS emission rates determined by both methods were comparable. The dynamic method provided positive OCS flux rates (emission) for measurements performed at sites containing Sphagnum. Conversely, data from the static method indicated that OCS was consumed from the atmosphere. Short and long-term impacts of increased S deposition on fluxes of volatile S compounds (VSC's) from Sphagnum peatlands were investigated in a poor fen (Mire 239) at the Experimental Lakes Area, Ontario, Canada. Additional experiments were conducted in a poor fen (Sallie's Fen in Barrington, NH, USA). At Mire 239, emissions of VSC's were monitored, before and after acidification, at control and experimental sections within two major physiographic areas of the mire (oligotrophic and minerotrophic). DMS was the predominant VSC released from Mire 239 and varied largely with time and space. Sulfur addition did not affect DMS emissions in a period of hours to a few days. DMS emissions in the experimental oligotrophic area of the mire was approximately 3-fold greater than in the control oligotrophic area, and approximately 10-fold greater than in the minerotrophic zones. These differences could be due to a combination of differences in types of vegetation, nutritional status, and S input. At Sallie's Fen, DMS fluxes were not significantly affected by sulfate amendments, while DMS and MSH concentrations increased greatly with time in the top 10 cm of the peat column. The major environmental factors controlling fluxes of DMS in a Sphagnum-dominated peatland were investigated in Sallie's Fen, NH. DMS emissions from the surface of the peatland varied greatly over 24 hours and seasonally. Temperature seemed to be the major environmental factor controlling these variabilities. Concentrations of dissolved VSC's varied with time and space throughout the fen

  16. Acceleration processes in the quasi-steady magnetoplasmadynamic discharge. Ph.D. Thesis

    Boyle, M. J.


    The flow field characteristics within the discharge chamber and exhaust of a quasi-steady magnetoplasmadynamic (MPD) arcjet were examined to clarify the nature of the plasma acceleration process. The observation of discharge characteristics unperturbed by insulator ablation and terminal voltage fluctuations, first requires the satisfaction of three criteria: the use of refractory insulator materials; a mass injection geometry tailored to provide propellant to both electrode regions of the discharge; and a cathode of sufficient surface area to permit nominal MPD arcjet operation for given combinations of arc current and total mass flow. The axial velocity profile and electromagnetic discharge structure were measured for an arcjet configuration which functions nominally at 15.3 kA and 6 g/sec argon mass flow. An empirical two-flow plasma acceleration model is advanced which delineates inner and outer flow regions and accounts for the observed velocity profile and calculated thrust of the accelerator.

  17. Numerical Modeling of a Vortex Stabilized Arcjet. Ph.D. Thesis, 1991 Final Report

    Pawlas, Gary E.


    Arcjet thrusters are being actively considered for use in Earth orbit maneuvering applications. Experimental studies are currently the chief means of determining an optimal thruster configuration. Earlier numerical studies have failed to include all of the effects found in typical arcjets including complex geometries, viscosity, and swirling flow. Arcjet geometries are large area ratio converging nozzles with centerbodies in the subsonic portion of the nozzle. The nozzle walls serve as the anode while the centerbody functions as the cathode. Viscous effects are important because the Reynolds number, based on the throat radius, is typically less than 1,000. Experimental studies have shown that a swirl or circumferential velocity component stabilizes a constricted arc. This dissertation describes the equations governing flow through a constricted arcjet thruster. An assumption that the flowfield is in local thermodynamic equilibrium leads to a single fluid plasma temperature model. An order of magnitude analysis reveals the governing fluid mechanics equations are uncoupled from the electromagnetic field equations. A numerical method is developed to solve the governing fluid mechanics equations, the Thin Layer Navier-Stokes equations. A coordinate transformation is employed in deriving the governing equations to simplify the application of boundary conditions in complex geometries. An axisymmetric formulation is employed to include the swirl velocity component as well as the axial and radial velocity components. The numerical method is an implicit finite-volume technique and allows for large time steps to reach a converged steady-state solution. The inviscid fluxes are flux-split, and Gauss-Seidel line relaxation is used to accelerate convergence. Converging-diverging nozzles with exit-to-throat area ratios up to 100:1 and annular nozzles were examined. Quantities examined included Mach number and static wall pressure distributions, and oblique shock structures. As

  18. Multiseasonal-multispectral remote sensing of phenological change for natural vegetation inventory. Ph.D. Thesis

    Schrumpf, B. J. (Principal Investigator)


    The author has identified the following significant results. Variations in phenological development among plant species was noted, as well as the tendency for the seasonal appearance of some vegetation types to be dominated by the appearance of one or a few similarly developing species. Most of the common plants in the study area could be characterized by temporal aspects of their phenological development. There was a strong similarity among the spectral signatures of vegetation types in which the spectral return was dominated by green plant material. When the soil background dominated the spectral return from a vegetation stand, then the spectral radiance and the vegetation physiognomy were apparently related. When the deciduous shrubs lost their leaves, their spectral signature altered with a slight decrease of radiance in the visible wavelengths and a strong decrease in the near infrared. As the foliage of perennial grasses cured from August to November, its apparent green radiance remained unchanged, red radiance increased over 50 percent, and near infrared radiance decreased approximately 30 percent. A reflective mineral surface exhibited high radiance levels in all four bands, thus providing a marked contrast to the absorption characteristics of vegetation canopies.

  19. Concurrent communication among multi-transceiver stations over shared media. Ph.D. Thesis

    Birk, Yitzhak


    In order to increase a local-area network's throughput beyond a single bus data rate without using dedicated switching nodes, multiple buses and multitransceiver stations are required. The design space of single-hop interconnections is explored among such stations. Interconnections are presented whose throughput can grow quadratically with the number of transmitters and receivers per station. These are referred to as selective broadcast interconnections (SBIs). The performance of various SBIs are studied. A spread-spectrum channel can accommodate several current successful transmission, and a single-transceiver node can thus utilize only a small fraction of the channel capacity. In order to allocate the appropriate fraction of capacity to a busy node, it is proposed to equip it with several transmitters and receivers, thereby turning it into a supernode. Several architectures and operation policies for supernodes are suggested and compared. It is shown that a supernode can significantly outperform a collection of independent conventional nodes with the same total numbers of transmitters and receivers. Packet-radio networks with half-duplex nodes, as well as networks with full-duplex nodes, are considered.

  20. Calculation of Propulsive Nozzle Flowfields in Multidiffusing Chemically Reacting Environments. Ph.D. Thesis - Purdue Univ.

    Kacynski, Kenneth John


    An advanced engineering model has been developed to aid in the analysis and design of hydrogen/oxygen chemical rocket engines. The complete multispecies, chemically reacting and multidiffusing Navier-Stokes equations are modelled, including the Soret thermal diffusion and the Dufour energy transfer terms. In addition to the spectrum of multispecies aspects developed, the model developed in this study is also conservative in axisymmetric flow for both inviscid and viscous flow environments and the boundary conditions employ a viscous, chemically reacting, reference plane characteristics method. Demonstration cases are presented for a 1030:1 area ratio nozzle, a 25 lbf film cooled nozzle, and a transpiration cooled plug and spool rocket engine. The results indicate that the thrust coefficient predictions of the 1030:1 and the 25 lbf film cooled nozzle are within 0.2 to 0.5 percent, respectively, of experimental measurements when all of the chemical reaction and diffusion terms are considered. Further, the model's predictions agree very well with the heat transfer measurements made in all of the nozzle test cases. The Soret thermal diffusion term is demonstrated to have a significant effect on the predicted mass fraction of hydrogen along the wall of the nozzle in both the laminar flow 1030:1 nozzle and the turbulent flow plug and spool nozzle analysis cases performed. Further, the Soret term was shown to represent an important fraction of the diffusion fluxes occurring in a transpiration cooled rocket engine.

  1. Optimization of microwave power transmission from solar power satellites. Ph.D. Thesis

    Potter, S.D.


    Solar energy can be used to avoid environmental problems associated with the use of fossil fuels. Because of limitations on the availability of solar energy at the Earth`s surface, it is recommended that energy from the sun be harnessed by solar collectors in geostationary orbit, known as solar power satellites (SPS). The energy collected is transmitted to the Earth by means of microwaves. The physics of power beaming is investigated through the use of mathematical analysis and numerical computer techniques. The most widely considered microwave frequency, 2.45 GHz, constrains the design of the SPS, due to the diffraction of the beam. Therefore, transmission through other atmospheric `windows` has been considered, notably 35 and 94 GHz. Although increasing the frequency decreases the size of the main beam lobe, and thus the rectifying antenna (rectenna) needed to capture the energy, the size of the exclusion zone needed to protect populations from microwave exposure is independent of frequency for a square transmitting antenna. Rain attenuation is significant above 15 GHz. In clear air, microwave absorption may lead to atmospheric heating effects, especially at 94 GHz. It is therefore recommended that future power beaming research concentrate on minimizing beam sidelobes, and increasing the frequency from 2.45 GHz to no more than 15 GHz. Circular transmitting antennas allow for smaller exclusion zones than square antennas. Furthermore, if the amplitude of the beam is varied, or tapered, across the face of the transmitting antenna, then the exclusion zones can be made even smaller. If the frequency is increased to 9.8 GHz, a moderate beam taper is used, and the peak beam intensity is kept to a few tens of milliwatts per square centimeter, then a larger number of somewhat smaller SPS`s will be needed to supply a given amount of power. This results in a net decrease in the land area needed for rectennas and exclusion zones.

  2. Processed data from neutron scattering experiments described in PhD thesis "NMR and neutron total scattering studies of silicon-based anode materials for lithium-ion batteries"

    Kerr, Christopher J


    The results of processing the data in the dataset "Raw data for neutron scattering experiments described in PhD thesis "NMR and neutron total scattering studies of silicon-based anode materials for lithium-ion batteries""

  3. PhD Students' Experiences of Thesis Supervision in Malaysia: Managing Relationships in the Midst of Institutional Change

    Krauss, Steven Eric; Ismail, Ismi Arif


    Despite the plethora of studies that have been conducted on PhD supervision, little qualitative investigation has been conducted with a diverse, non-Western sample of doctoral students in an attempt to understand how the supervisory relationship is experienced. In response, eighteen students from diverse, non-Western backgrounds studying at one…

  4. Detectors for the study of the proton-proton interaction at very high energies. Resume of Ph.D thesis

    Extremely attractive for precision tracking in HEP experiments due to their unsurpassed speed and resolution, silicon detectors have been proposed for the central trackers in the future p-p experiments ATLAS and CMS at LHC. The LHC radiation environment is extremely hostile and special radiation hardness studies are needed to ensure the survivability of the detectors for ten years. Most of the radiation damage tests are performed in neutron fields, at various irradiation facilities. They should be characterized with respect to spectra, fluence temperature and stray radiation. Frequently used sources, including the NINPE ΣΣ facility, are analyzed in a systematic way. The principles of operation of silicon detectors and the main parameters of interest for damage studies are summarized in a separate chapter. Based on this, a vast discussion is given illustrated with experimental results on bulk damage in pad and microstrip detectors, irradiated at the IBR-2 reactor at JINR Dubna and ΣΣ facility at NINPE. Damage constant and annealing are studied. The correlation of the experimental results obtained at different facilities is done via the NIEL scaling. The scaling factor is the hardness parameter. The thesis is the first complete analysis of the NIEL hypothesis together with detailed results on hardness parameter and relative damage calculations for all the spectra used for testing and those foreseen in ATLAS and CMS. The thesis gives a complete description of the present status of the knowledge of the macroscopic parameters in bulk damage in silicon detectors, irradiation sources and the NIEL scaling. It discusses the limits of error we expect from the estimates on damage, and example of how radiation hardness results can be used in the design of an experiment. (author).10 Figs., 4 Tabs., 33 Refs

  5. Perovskite ceramics with high merit factor and their application in IR radiation detection .Resume of Ph.D thesis

    Ferroelectric materials with perovskite structure are studied in the thesis from the point of view of their pyroelectric properties. Ceramic materials of PZT type, with different chemical compositions are prepared using hot-pressing method. The values of the main electrical parameters are determined. The figure of merit for I.R. detection is computed in different working conditions of the pyroelectric detectors manufactured from the studied materials. A new method is proposed for the enhancement of the pyroelectric coefficient value. It is shown that using pyroelectric bimorph structures, with series connection, it is possible to obtain a considerable improvement (around 30%) of the pyroelectric coefficient and, consequently, of the figure of merit. Also, it is shown that the bimorph properties are strongly influenced by the charge exchange that takes place between the two component phases during heating. The temperature dependence of the pyroelectric current and spontaneous polarization are explained considering the hypothesis of a pyroelectric charge redistribution when the bimorph temperature varies. The behaviour of a pyroelectric ceramic subject to a static electric field was also studied. It was shown that the values of the pyroelectric current and spontaneous polarization are strongly influenced by the value and orientation of the applied field. Finally, the studied materials are used for manufacturing pyroelectric detectors and pyroelectric linear arrays. The pyroelectric detectors were then used to produce non-contact thermometers (heat-spies). (author) 13 figs., 6 tabs., 45 refs

  6. Structure and grain coarsening during the processing of engineering ceramics. Ph.D. Thesis - Leeds Univ., United Kingdom

    Shaw, Nancy J.


    Studies have been made of three ceramic systems (Al2O3, Y2O3/MgO, and SiC/C/B), both to explore a surface area/density diagram approach to examining the coarsening processes during sintering and to explore an alternative coarsening parameter, i.e., the grain boundary surface area (raising it at a given value of the density) and not the pore surface area; therefore, pinning of the grain boundaries by solid-solution drag is the only function evidenced by these results. The importance of such pinning even at densities as low as 75% of theoretical is linked to the existence of microstructural inhomogeneities. The early stages of sintering of Y2O3 powder have been examined using two techniques, BET surface area analysis and transmission electron microscopy. Each has given some insight into the process occurring and, used together, have provided some indication of the effect of MgO on coarsening during sintering. Attempts to further elucidate effects of MgO on the coarsening behavior of Y2O3 by the surface area/density diagram approach were unsuccessful due to masking effects of contaminating reactions during sintering and/or thermal etching. The behavior of the undoped SiC which only coarsens can be clearly distinguished by the surface area/density diagram from that of SiC/C/B which also concurrently densifies. Little additional information was obtainable by this method due to unfavorable sample etching characteristics. The advantages, disadvantages, and difficulties of application of these techniques to the study of coarsening during sintering are discussed.

  7. A Management Information System Model for Program Management. Ph.D. Thesis - Oklahoma State Univ.; [Computerized Systems Analysis

    Shipman, D. L.


    The development of a model to simulate the information system of a program management type of organization is reported. The model statistically determines the following parameters: type of messages, destinations, delivery durations, type processing, processing durations, communication channels, outgoing messages, and priorites. The total management information system of the program management organization is considered, including formal and informal information flows and both facilities and equipment. The model is written in General Purpose System Simulation 2 computer programming language for use on the Univac 1108, Executive 8 computer. The model is simulated on a daily basis and collects queue and resource utilization statistics for each decision point. The statistics are then used by management to evaluate proposed resource allocations, to evaluate proposed changes to the system, and to identify potential problem areas. The model employs both empirical and theoretical distributions which are adjusted to simulate the information flow being studied.

  8. A study of quadrupole dynamics: quantification of classical motion chaos, and new features of the coherent states model. Resume of Ph.D thesis

    This resume of the Ph.D. thesis has three main parts. In the first part a fourth order quadrupole boson Hamiltonian is semi classically treated through a time-dependent variational principle (TDVP), the variational states being of coherent type for the boson operators b20+ and 1/√2 (b22+ + b2-2+). The static ground state is studied as a function of the parameters involved in the model Hamiltonian. Linearizing the classical equations of motion one obtains the RPA approach for the many boson correlations. There are two RPA roots which describe the beta and gamma vibrations, respectively. Several quantization procedures for both small and large amplitude regimes are discussed. The quantized Hamiltonians are compared with some others which were previously obtained by using different methods. A special attention is paid to the quantal states associated to some of the peaks appearing in the Fourier spectrum of the classical action density. Some of the quantal states exhibit a pronounced anharmonic structure. Therefore the procedure may be used for a unified description of small and large amplitude regimes. In the next part the semiclassical foundations of the Coherent State Model are established using the formalism elaborated in the previous section. In the third part the semiclassical treatment through a time-dependent variational principle (TDVP) of the fourth order quadrupole boson Hamiltonian H is continued. In the parameter space of H there are regions, conventionally called as 'nuclear phases', determining specific static properties. Several ground states corresponding to different equilibrium shapes are found as static solutions of classical equations of motion. The non-integrable system may follow a chaotic trajectory. The mechanism of destroying the tori bearing regular orbits and the onset of chaos may depend on nuclear phase. The regular and chaotic motions are analyzed in terms of Poincare sections and Lyapunov largest exponent. Specific features of various

  9. An analysis of Ph.D. examiners' reports in engineering

    Prieto, Elena; Holbrook, Allyson; Bourke, Sid


    In recent years, there have been increasing calls for an overall transformation of the nature of engineering Ph.D. programs and the way theses are assessed. There exists a need to understand the examination process to ensure the best quality outcome for candidates in engineering. The work we present in this paper uses data collected between 2003 and 2010 for a total of 1220 Australian Ph.D. theses by analysing examiner reports. Our analysis indicates that Ph.D. theses in engineering, N = 106, differ considerably from those in other fields in areas such as gender of candidates and examiners and the examiners' geographical location. We also found that assessment areas such as significance and contribution of the thesis, publications arising from the thesis, breadth, depth and recency of the literature review and communication and editorial correctness are areas in which the proportion of text of engineering examiners' comments differs significantly from other fields.

  10. Numerical Prediction of Turbulent Oscillating Flow and Heat Transfer in Pipes with Various End Geometries. Ph.D. Thesis, Final Report

    Oseid, Kirk Leroi


    Unsteady flow is present in man, machine and nature. The flow of blood in arteries and capillaries in the human body is pulsatile-composed of a mean flow superposed with an oscillating component. The tides that wash in and out of rivers, harbors and estuaries are unsteady flows with very long periods of oscillation. Many engineering devices employ pulsatile and oscillating flow. Pulsating flow is defined here as a periodic flow with a net displacement of fluid over each flow cycle. Oscillating flow is defined as a period flow with a zero mean over each cycle. The subject of this thesis is oscillating flow and heat transfer in pipes which make up the heater and cooler sections of the NASA Space Power Research Engine (SPRE) currently under development. This engine uses the Stirling cycle as the thermal energy converter in a power plant for future space applications. The information presented in this thesis will of course be applicable to the design of many types of machinery which employ oscillating flow and heat transfer.

  11. ATLAS PHd Grants 2015

    Marcelloni De Oliveira, Claudia


    ATLAS PHd Grants - We are excited to announce the creation of a dedicated grant scheme (thanks to a donation from Fabiola Gianotti and Peter Jenni following their award from the Fundamental Physics Prize foundation) to encourage young and high-caliber doctoral students in particle physics research (including computing for physics) and permit them to obtain world class exposure, supervision and training within the ATLAS collaboration. This special PhD Grant is aimed at graduate students preparing a doctoral thesis in particle physics (incl. computing for physics) to spend one year at CERN followed by one year support also at the home Institute.

  12. Ph.D. thesis carried out at Uppsala University: Health-Related Quality of Life and Return to Work following Breast Cancer

    Høyer Lundh, Marie


    -cancer-free controls. Questionnaire data on HRQoL, socio-demographics and work-related variables were combined with clinical register, normative and social insurance data. Results Following deteriorations within eight months post-diagnosis, HRQoL generally improved during the three years studied. The majority of women...... returned to work and sickness absence steadily decreased, but, compared with the controls, the odds of being on sick leave were increased all three years post-diagnosis. Chemotherapy, young age and sick leave/disability pension pre-diagnosis were associated with poorer HRQoL, decreased working time......L) and return to work in the first three years following a breast cancer diagnosis, and to identify clinical and contextual factors associated with these outcomes. Methods All four papers in the thesis were part of a population-based cohort study including women registered in the Breast Cancer Quality...

  13. BETA: Behavioral testability analyzer and its application to high-level test generation and synthesis for testability. Ph.D. Thesis

    Chen, Chung-Hsing


    In this thesis, a behavioral-level testability analysis approach is presented. This approach is based on analyzing the circuit behavioral description (similar to a C program) to estimate its testability by identifying controllable and observable circuit nodes. This information can be used by a test generator to gain better access to internal circuit nodes and to reduce its search space. The results of the testability analyzer can also be used to select test points or partial scan flip-flops in the early design phase. Based on selection criteria, a novel Synthesis for Testability approach call Test Statement Insertion (TSI) is proposed, which modifies the circuit behavioral description directly. Test Statement Insertion can also be used to modify circuit structural description to improve its testability. As a result, Synthesis for Testability methodology can be combined with an existing behavioral synthesis tool to produce more testable circuits.

  14. Estimation of absorbed gamma dose in air due to natural and artificial radioactivity of soil. Resume of Ph.D thesis

    This is an extended abstract of the Ph. D. thesis devoted to the measurements of air absorbed gamma doses due to natural and artificial radioactivity in soil. It contains a summary of the four chapters of the thesis. The first chapter presents problems related to the measurement of natural and artificial radioactivity coming from soil contamination due to nuclear explosions or nuclear accidents. The natural and artificial radionuclides which usually contaminate the soil are reviewed. The chapter two presents the original contribution of the author in the field of the methods of soil sampling and NaI(Tl) gamma spectrometry analysis of radioactive samples. Also the results of the measurements carried out in 10 counties in Romania are here reported. The natural radionuclides measured were Ra-226, Th-232, and K-40, while the artificial radionuclides were Cs-137 and Cs-134. In the third chapter the radioactivity levels are reported as absorbed air gamma doses due to presence of 137 Cs and 134 Cs in soil. Also here the effective dose equivalents estimated for the population of the 10 counties are presented. In the concluding chapter four a discussion is given concerning the dose levels measured following the Chernobyl nuclear accident as function of time elapsed from the accident and of depth of soil sampling and of soil type. It is shown that the dose levels which affected the population in the studied zones are within the values of radioprotection standards in Romania. These data were used as input to solve the problem of the biological effects of low doses on the population health. (M.I.C.). 7 Figs., 10 Tabs., 73 Refs

  15. Constraints on the neutrino parameters by future cosmological 21cm line and precise CMB polarization observations (PhD thesis, The Graduate University for Advanced Studies (SOKENDAI))

    Oyama, Yoshihiko


    Observations of the 21 cm line radiation coming from the epoch of reionization have a great capacity to study the cosmological growth of the Universe. Also, CMB polarization produced by gravitational lensing has a large amount of information about the growth of matter fluctuations at late time. In this thesis, we investigate their sensitivities to the impact of neutrino property on the growth of density fluctuations, such as the total neutrino mass, the neutrino mass hierarchy, the effective number of neutrino species (extra radiation), and the lepton asymmetry of our Universe. We will show that by combining the precise CMB polarization observations with Square Kilometer Array (SKA) we can measure the impact of non-zero neutrino mass on the growth of density fluctuation, and determine the neutrino mass hierarchy at 2 sigma level if the total neutrino mass is smaller than 0.1 eV. Additionally, we will show that by using these combinations we can constrain the lepton asymmetry better than big-bang nucleosynthes...

  16. The intercrater plains of Mercury and the Moon: Their nature, origin and role in terrestrial planet evolution. Measurement and errors of crater statistics. Ph.D. Thesis

    Leake, M. A.


    Planetary imagery techniques, errors in measurement or degradation assignment, and statistical formulas are presented with respect to cratering data. Base map photograph preparation, measurement of crater diameters and sampled area, and instruments used are discussed. Possible uncertainties, such as Sun angle, scale factors, degradation classification, and biases in crater recognition are discussed. The mathematical formulas used in crater statistics are presented.

  17. A Programming Environment Evaluation Methodology for Object-Oriented Systems. Ph.D Thesis Final Report, 1 Jul. 1985 - 31 Dec. 1987

    Dominick, Wayne D. (Editor); Moreau, Dennis R.


    The object-oriented design strategy as both a problem decomposition and system development paradigm has made impressive inroads into the various areas of the computing sciences. Substantial development productivity improvements have been demonstrated in areas ranging from artificial intelligence to user interface design. However, there has been very little progress in the formal characterization of these productivity improvements and in the identification of the underlying cognitive mechanisms. The development and validation of models and metrics of this sort require large amounts of systematically-gathered structural and productivity data. There has, however, been a notable lack of systematically-gathered information on these development environments. A large part of this problem is attributable to the lack of a systematic programming environment evaluation methodology that is appropriate to the evaluation of object-oriented systems.

  18. An Investigation into Automatically Captured Autobiographical Metadata, and the Support for Autobiographical Narrative Generation. Mini-Thesis: PhD upgrade report

    Tuffield, Mischa M; Millard, David E.; Shadbolt, Nigel R.


    Personal information and the act of publishing multimedia artifacts to the World Wide Web is becoming more and more observable. This report presents an infrastructure for the capturing and exploitation of personal metadata to drive research into context aware systems. I aim to expose ongoing research in the areas of capture of personal experiences, context aware systems, multimedia annotation systems, narrative generation, and that of Semantic Web enabling technologies. This report details th...

  19. Investigations of primary and secondary impact structures on the moon and laboratory experiments to study the ejecta of secondary particles. Ph.D. Thesis - Ruprecht Karl Univ.

    Koenig, B.


    Young lunar impact structures were investigated by using lunar orbiter, Apollo Metric and panorama photographs. Measurements on particularly homogeneous areas low in secondary craters made possible an expansion of primary crater distribution to small diameters. This is now sure for a range between 20m or = D or = 20km and this indicates that the size and velocity distribution of the impacting bodies in the last 3 billion years has been constant. A numerical approximation in the form of a 7th degree polynomial was obtained for the distribution.

  20. The effect of hydrogen and microstructure on the deformation and fracture behavior of a single crystal nickel-base superalloy. Final Report Ph.D. Thesis

    Walston, William S.


    A study was conducted on the effects of internal hydrogen and microstructure on the deformation and fracture of a single crystal nickel-base superalloy. In particular, room temperature plane strain fracture toughness and tensile tests were performed on hydrogen-free and hydrogen charged samples of PWA 1480. The role of microstructure was incorporated by varying the levels of porosity and eutectic gamma/gamma prime through hot isostatic pressing and heat treatment. The room temperature behavior of PWA 1480 was unusual because precipitate shearing was not the primary deformation mechanism at all strains. At strains over 1 percent, dislocations were trapped in the gamma matrix and an attempt was made to relate this behavior to compositional differences between PWA 1480 and other superalloys. Another unique feature of the tensile behavior was cleavage of the eutectic gamma/gamma prime, which is believed to initiate the failure process. Fracture occurred on (111) planes and is likely a result of shear localization along these planes. Elimination of the eutectic gamma/gamma prime greatly improved the tensile ductility, but pososity had no effect on tensile properties. Large quantities of hydrogen (1.74 at. percent) were gas-phase charged into the material, but surprisingly this was not a function of the amount of porosity or eutectic gamma/gamma prime present. Desorption experiments suggest that the vast majority of hydrogen is at reversible lattice trapping sites. This large, uniform concentration of hydrogen dramatically reduced the tensile strain to failure, but only slightly affected the reduction in area. Available hydrogen embrittlement models were examined in light of these results and it was found that the hydrogen enhanced localized plasticity model can explain much of the tensile behavior. K(IC) fracture toughness tests were conducted, but it was necessary to also perform J(IC) tests to provide valid data.

  1. PhD Dissertations

    Redazione Reti Medievali (a cura di


    Full Text Available Report of PhD Dissertations. Guido Antonioli Conservator pacis et iustitie. La signoria di Taddeo Pepoli a Bologna (1337-1347, Tesi di dottorato di ricerca in Filologia romanza e cultura medievale (XIII ciclo, Università degli Studi di Bologna, 2001   Elisabetta Filippini «In vassallatico episcopi permanere debent». Rapporti vassallatici e concessioni beneficiali dei vescovi di Cremona fra X e XIII secolo, Tesi di dottorato di Ricerca in Storia Medievale (XV ciclo, Università Cattolica del Sacro Cuore di Milano, 2003   Marco Meschini, Innocenzo III e il "negotium pacis et fidei" in Linguadoca tra il 1198 e il 1215, Tesi di dottorato di ricerca in Storia medievale, Università Cattolica del Sacro Cuore, 2003   Fabrizio Ricciardelli The Politics of Exclusion in Florence (1215-1434, thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in History, University of Warwick, Department of History, April 2003 Renata Salvarani Baptizare pueros et decimas dare. Cura delle anime, strutturazione ecclesiastica e organizzazione delle campagne in area gardesana fra VIII e XIII secolo (diocesi di Brescia, Verona, Mantova e Trento, Tesi di dottorato in Storia medievale (XV ciclo, Università Cattolica del Sacro Cuore di Milano, 2002-2003   Vito Sibilio Le parole della prima crociata, Tesi di dottorato di ricerca in Storia dei centri delle vie e della cultura dei pellegrinaggi nel medioevo euromediterraneo, Università degli studi di Lecce, 2003

  2. Pursuit of the Ph.D.

    Scott P. Kerlin


    Full Text Available he thesis is put forward that changes in public policy which originally promoted broad access to higher education are leading to the diminished likelihood that minorities, those from low-income backgrounds and females in underrepresented disciplines will pursue, or be able to complete, the doctorate. By reviewing a wide range of research literature and statistical reports on the status of doctoral education in the U.S. & Canada, a detailed sociological portrait of those who pursue the Ph.D. is presented. Recommendations are given for further research on doctoral education, particularly in areas of attrition,retention, student indebtedness, social stratification, and post-doctoral career plans.

  3. Lynn Sorbara, PhD | Division of Cancer Prevention

    Dr. Lynn Sorbara earned her PhD from Albert Einstein College of Medicine in 1986. Her thesis research was in the areas of the mechanism of action of the drug, Taxol, and of multidrug resistance. After postdoctoral fellowships at the Rockefeller University and the Mount Sinai College of Medicine in Manhattan, she came to the NIH as a Senior Staff Fellow in the Diabetes Branch of NIDDK. |

  4. Award for the best CMS thesis


    The 2002 CMS PhD Thesis Award for has been presented to Giacomo Luca Bruno for his thesis defended at the University of Pavia in Italy and entitled "The RPC detectors and the muon system for the CMS experiment at the LHC". His work was supervised by Sergio P. Ratti from the University of Pavia. Since April 2002, Giacomo has been employed as a research fellow by CERN's EP Division. He continues to work on CMS in the areas of data acquisition and physics reconstruction and selection. Last Monday he received a commemorative engraved plaque from Lorenzo Foà, chairman of the CMS Collaboration Board. He will also receive expenses paid to an international physics conference to present his thesis results. Giacomo Luca Bruno with Lorenzo Foà

  5. CMS Thesis Award


    The 2003 CMS thesis award was presented to Riccardo Ranieri on 15 March for his Ph.D. thesis "Trigger Selection of WH → μ ν b bbar with CMS" where 'WH → μ ν b bbar' represents the associated production of the W boson and the Higgs boson and their subsequent decays. Riccardo received his Ph.D. from the University of Florence and was supervised by Carlo Civinini. In total nine thesis were nominated for the award, which was judged on originality, impact within the field of high energy physics, impact within CMS and clarity of writing. Gregory Snow, secretary of the awarding committee, explains why Riccardo's thesis was chosen, ‘‘The search for the Higgs boson is one of the main physics goals of CMS. Riccardo's thesis helps the experiment to formulate the strategy which will be used in that search.'' Lorenzo Foà, Chairperson of the CMS Collaboration Board, presented Riccardo with an commemorative engraved plaque. He will also receive the opportunity to...

  6. Hrvoje Tomić, PhD in Technical Sciences

    Siniša Mastelić Ivić


    Full Text Available Hrvoje Tomić defended his PhD thesis Geospatial Data Analysis for the Purpose of Real Estate Valuation in Urban Areas at the Faculty of Geodesy, University of Zagreb, on November 15, 2010. His mentor was Prof. Dr. Siniša Mastelić Ivić, and the other two members of the Grading and Defence Committee were Assist. Prof. Dr. Vlado Cetl and Prof. Dr. Goran Poljanec from the Faculty of Civil Engineering, University of Zagreb.

  7. Ante Šiljeg, PhD in Interdisciplinary Sciences

    Sanja Lozić


    Full Text Available Ante Šiljeg defended his doctoral thesis The Digital Relief Model in Analysis of Geomorphometric Parameters – Example of PP Vrana Lake at Faculty of Science, University of Zagreb on June 20th, 2013 (supervisor Sanja Lozić, PhD, assistant professor and received a PhD degree in the field of interdisciplinary science, field of geography, branch of applied geography. Doctoral thesis was defended in front of committee composed of Mladen Pahernik, PhD, assistant professor, Danijel Orešić, PhD, associate professor and Aleksandar Toskić, PhD, associate professor. Commitee for disertation review was in the same composition.

  8. The intercrater plains of Mercury and the Moon: Their nature, origin and role in terrestrial planet evolution. Estimated thickness of ejecta deposits compared to to crater rim heights. Ph.D. Thesis

    Leake, M. A.


    The area of the continuous ejecta deposits on mercury was calculated to vary from 2.24 to 0.64 times the crater's area for those of diameter 40 km to 300 km. Because crater boundaries on the geologic map include the detectable continuous ejecta blanket, plains exterior to these deposits must consist of farther-flung ejecta (of that or other craters), or volcanic deposits flooding the intervening areas. Ejecta models are explored.

  9. Thesis Proposal

    Sloth, Erik


    Strukturen i Thesis proposal er følgende: Først præsenteres mine konkrete empiriske forskningsprojekter som skal munde ud i afhandlingens artikler. Jeg præsenterer herefter de teoretiske overvejelser omkring oplevelsesbegrebet og forbrugerkulturteori som danner baggrund for at jeg er nået frem til...

  10. Bachelor thesis



    The aim of the bachelor thesis was to create a survey of characteristics of pork meat quality including pH45, pH24, colour, water holding capacity, texture, intramuscular fat content and influences that affect the meat quality, i.e. breed, sex, slaughter weight, nutrition and feed, stabling technology, treatment, transport to the slaughterhouse, method of stunning and way of slaughter. The meat quality is also conditioned by the chemical composition, physical and technological features of the...

  11. Thermal Stability of Distillate Hydrocarbon Fuels. Ph.D. Thesis

    Reddy, Kishenkumar Tadisina; Cernansky, Nicholas P.


    Thermal stability of fuels is expected to become a severe problem in the future due to the anticipated use of broadened specification and alternative fuels. Future fuels will have higher contents of heteroatomic species which are reactive constituents and are known to influence fuel degradation. To study the degradation chemistry of selected model fuels, n-dodecane and n-dodecane plus heteroatoms were aerated by bubbling air through the fuels amd stressed on a modified Jet Fuel Thermal Oxidation Tester facility operating at heater tube temperatures between 200 to 400 C. The resulting samples were fractionated to concentrate the soluble products and then analyzed using gas chromatographic and mass spectrometric techniques to quantify and identify the stable reaction intermediate and product specifically. Heteroatom addition showed that the major soluble products were always the same, with and without heteroatoms, but their distributions varied considerably.

  12. Communication theory of quantum systems. Ph.D. Thesis, 1970

    Yuen, H. P. H.


    Communication theory problems incorporating quantum effects for optical-frequency applications are discussed. Under suitable conditions, a unique quantum channel model corresponding to a given classical space-time varying linear random channel is established. A procedure is described by which a proper density-operator representation applicable to any receiver configuration can be constructed directly from the channel output field. Some examples illustrating the application of our methods to the development of optical quantum channel representations are given. Optimizations of communication system performance under different criteria are considered. In particular, certain necessary and sufficient conditions on the optimal detector in M-ary quantum signal detection are derived. Some examples are presented. Parameter estimation and channel capacity are discussed briefly.

  13. Applications of industrial engineering. Ph.D. Thesis

    Yarbrough, Walthea V.


    Two separate and distinctly different projects are described within this paper: the stepping motion bearing tester, and the memo search and find project. The objective of the first project was to program the JSI Digital Servo Controller to control the motor using the stepping pattern prescribed by the AMSU-U2 Scan Profile. The objective of the second project was to develop a dBASE 3 Plus program that would allow the user to gain the necessary information to retrieve the memo(s) being sought upon supplying a word or group of words possibly found in the keyword list or upon supplying the author's name.

  14. Stratigraphy and Tectonics of Southeastern Serenitatis. Ph.D. Thesis

    Maxwell, T. A.


    Results of investigations of returned Apollo 17 samples, and Apollo 15 and 17 photographs have provided a broad data base on which to interpret the southeastern Serenitatis region of the moon. Although many of the pre-Apollo 17 mission interpretations remain valid, detailed mapping of this region and correlation with earth-based and orbital remote-sensing data have resulted in a revision of the local mare stratigraphy.

  15. Controlling Flexible Manipulators, an Experimental Investigation. Ph.D. Thesis

    Hastings, Gordon Greene


    Lightweight, slender manipulators offer faster response and/or greater workspace range for the same size actuators than tradional manipulators. Lightweight construction of manipulator links results in increased structural flexibility. The increase flexibility must be considered in the design of control systems to properly account for the dynamic flexible vibrations and static deflections. Real time control of the flexible manipulator vibrations are experimentally investigated. Models intended for real-time control of distributed parameter system such as flexible manipulators rely on model approximation schemes. An linear model based on the application of Lagrangian dynamics to a rigid body mode and a series of separable flexible modes is examined with respect to model order requirements, and modal candidate selection. Balanced realizations are applied to the linear flexible model to obtain an estimate of appropriate order for a selected model. Describing the flexible deflections as a linear combination of modes results in measurements of beam state, which yield information about several modes. To realize the potential of linear systems theory, knowledge of each state must be available. State estimation is also accomplished by implementation of a Kalman Filter. State feedback control laws are implemented based upon linear quadratic regulator design.

  16. Molecular clouds in Orion and Monoceros. Ph.D. Thesis

    About one-eighth of a well-sampled 850 deg. sq. region of Orion and Monoceros shows CO emission coming from either local clouds (d < 1 kpc) lying as much as 25 deg. from the galactic plane or from more distant objects located within a few degrees of the plane. Local giant clouds associated with Orion A and B have enhanced temperatures and densities near their western edges possibly due to compression by a high pressure region created by approx.10 supernovae that occurred in the Orion OB association. Another giant cloud associated with Mon R2 may be related to the Orion clouds. Two filamentary clouds (one possibly 300 pc long but 10 pc wide) may represent a new class of object. An expanding ring of clouds concentric with the H II region ionized by lambda Ori probably constitute fragments of the original cloud from which lambda Ori formed; the gas pressure of the H II region and the rocket effect probably disrupted the original cloud. At a distance of 3 kpc, a large (250 x 100 pc) and massive (7-11x10 to the 5th power solar mass) cloud was found with the unusual combination of low temperatures (T sub R < 2.7 K) and wide spectral lines (approx. 7 km /sec). Most of the signs of star formation expected for such a massive cloud being absent, this may be a young cloud that has not yet started to form stars. The approx. 15 large clouds found in the outer galaxy (1 approx. 206 deg. - 220 deg.) probably lie in two spiral arms. The distribution of outer galaxy clouds and a comparison of the properties of these clouds and those of local clouds are given

  17. Quantization of gauge theories. Resume of Ph.D thesis

    The resume contains five chapters and a reference list. list. The chapters are: 1. Introduction; 2. Classical BRST symmetry , with 2.1: Elements of homologous perturbation theory; 2.2: Hamiltonian BRST symmetry; 2.3: Lagrangian BRST symmetry; 2.4:Examples; 3. The BRST quantization of class II systems, with 3.1: BRST quantization of class II systems in the original phase space; 3.2: Examples; 3.3: The BRST quantization of systems with only class II constraints in the extended phase space; 3.4: Examples; 3.5: The BRST quantization of the systems linear in derivatives; 4. The BRST - anti-BRST antibracket-antifield, with 4.1: The construction of Lagrangian BRST - anti- BRST symmetry; 4.2 Quantization of BRST - anti-BRST Abelian 3-forms; 5. Conclusions. 116 refs

  18. Research of PHD and Sports Education Media Master Thesis



    The access to relevant literature, This paper has discussed the research situation and significance of International Sports Education Media Politics through accessing to some relevant documents and materials, and has selected some important research achievements of Doctors’ and Maters’ papers on the topic of International Sports Education Media Politics, and also made recommendation and comments, e.g.

  19. Characterization of measurements in quantum communication. Ph.D. Thesis

    Chan, V. W. S.


    A characterization of quantum measurements by operator valued measures is presented. The generalized measurements include simultaneous approximate measurement of noncommuting observables. This characterization is suitable for solving problems in quantum communication. Two realizations of such measurements are discussed. The first is by adjoining an apparatus to the system under observation and performing a measurement corresponding to a self-adjoint operator in the tensor-product Hilbert space of the system and apparatus spaces. The second realization is by performing, on the system alone, sequential measurements that correspond to self-adjoint operators, basing the choice of each measurement on the outcomes of previous measurements. Simultaneous generalized measurements are found to be equivalent to a single finer grain generalized measurement, and hence it is sufficient to consider the set of single measurements. An alternative characterization of generalized measurement is proposed. It is shown to be equivalent to the characterization by operator-values measures, but it is potentially more suitable for the treatment of estimation problems. Finally, a study of the interaction between the information-carrying system and a measurement apparatus provides clues for the physical realizations of abstractly characterized quantum measurements.

  20. Topics in vacuum decay (Ph.D Thesis)

    Masoumi, Ali


    If a theory has more than one classically stable vacuum, quantum tunneling and thermal jumps make the transition between the vacua possible. The transition happens through a first order phase transition started by nucleation of a bubble of the new vacuum. The outward pressure of the truer vacuum makes the bubble expand and consequently eat away more of the old phase. In the presence of gravity this phenomenon gets more complicated and meanwhile more interesting. It can potentially have import...

  1. On reliable control system designs. Ph.D. Thesis; [actuators

    Birdwell, J. D.


    A mathematical model for use in the design of reliable multivariable control systems is discussed with special emphasis on actuator failures and necessary actuator redundancy levels. The model consists of a linear time invariant discrete time dynamical system. Configuration changes in the system dynamics are governed by a Markov chain that includes transition probabilities from one configuration state to another. The performance index is a standard quadratic cost functional, over an infinite time interval. The actual system configuration can be deduced with a one step delay. The calculation of the optimal control law requires the solution of a set of highly coupled Riccati-like matrix difference equations. Results can be used for off-line studies relating the open loop dynamics, required performance, actuator mean time to failure, and functional or identical actuator redundancy, with and without feedback gain reconfiguration strategies.

  2. Video transmission on ATM networks. Ph.D. Thesis

    Chen, Yun-Chung


    The broadband integrated services digital network (B-ISDN) is expected to provide high-speed and flexible multimedia applications. Multimedia includes data, graphics, image, voice, and video. Asynchronous transfer mode (ATM) is the adopted transport techniques for B-ISDN and has the potential for providing a more efficient and integrated environment for multimedia. It is believed that most broadband applications will make heavy use of visual information. The prospect of wide spread use of image and video communication has led to interest in coding algorithms for reducing bandwidth requirements and improving image quality. The major results of a study on the bridging of network transmission performance and video coding are: Using two representative video sequences, several video source models are developed. The fitness of these models are validated through the use of statistical tests and network queuing performance. A dual leaky bucket algorithm is proposed as an effective network policing function. The concept of the dual leaky bucket algorithm can be applied to a prioritized coding approach to achieve transmission efficiency. A mapping of the performance/control parameters at the network level into equivalent parameters at the video coding level is developed. Based on that, a complete set of principles for the design of video codecs for network transmission is proposed.

  3. Nonlinear damping model for flexible structures. Ph.D. Thesis

    Zang, Weijian


    The study of nonlinear damping problem of flexible structures is addressed. Both passive and active damping, both finite dimensional and infinite dimensional models are studied. In the first part, the spectral density and the correlation function of a single DOF nonlinear damping model is investigated. A formula for the spectral density is established with O(Gamma(sub 2)) accuracy based upon Fokker-Planck technique and perturbation. The spectral density depends upon certain first order statistics which could be obtained if the stationary density is known. A method is proposed to find the approximate stationary density explicitly. In the second part, the spectral density of a multi-DOF nonlinear damping model is investigated. In the third part, energy type nonlinear damping model in an infinite dimensional setting is studied.

  4. An Investigation of Generic Structures of Pakistani Doctoral Thesis Acknowledgements

    Rofess, Sakander; Mahmood, Muhammad Asim


    This paper investigates Pakistani doctoral thesis acknowledgements from genre analysis perspective. A corpus of 235 PhD thesis acknowledgements written in English was taken from Pakistani doctoral theses collected from eight different disciplines. HEC Research Repository of Pakistan was used as a data sources. The theses written by Pakistani…

  5. What Works for Doctoral Students in Completing Their Thesis?

    Lindsay, Siân


    Writing a thesis is one of the most challenging activities that a doctoral student must undertake and can represent a barrier to timely completion. This is relevant in light of current and widespread concerns regarding doctoral completion rates. This study explored thesis writing approaches of students post or near Ph.D. completion through…

  6. Tracking the PhD Students' Daily Computer Use

    Sim, Kwong Nui; van der Meer, Jacques


    This study investigated PhD students' computer activities in their daily research practice. Software that tracks computer usage (Manic Time) was installed on the computers of nine PhD students, who were at their early, mid and final stage in doing their doctoral research in four different discipline areas (Commerce, Humanities, Health Sciences and…

  7. Study of the cerrado vegetation in the Federal District area from orbital data. M.S. Thesis

    Dejesusparada, N. (Principal Investigator); Aoki, H.; Dossantos, J. R.


    The physiognomic units of cerrado in the area of Distrito Federal (DF) were studied through the visual and automatic analysis of products provided by Multispectral Scanning System (MSS) of LANDSAT. The visual analysis of the multispectral images in black and white, at the 1:250,000 scale, was made based on the texture and tonal patterns. The automatic analysis of the compatible computer tapes (CCT) was made by means of IMAGE-100 system. The following conclusions were obtained: (1) the delimitation of cerrado vegetation forms can be made by the visual and automatic analysis; (2) in the visual analysis, the principal parameter used to discriminate the cerrado forms was the tonal pattern, independently of the year's seasons, and the channel 5 gave better information; (3) in the automatic analysis, the data of the four channels of MSS can be used in the discrimination of the cerrado forms; and (4) in the automatic analysis, the four channels combination possibilities gave more information in the separation of cerrado units when soil types were considered.

  8. Precautionary interventions in industrial areas. An optimal stopping approach

    The contribution consists of an abstract of a PhD thesis. The thesis deals with the precautionary evacuation of an industrial facility's workforce threatened by a radiological release from a nuclear power plant nearby. The issue of deferring intervention decisions until additional information is available is addressed. Furthermore, interventions in industrial areas with a concentration of chemical and petrochemical plants form part of this study

  9. Precautionary interventions in industrial areas. An optimal stopping approach

    Pauwels, N


    The contribution consists of an abstract of a PhD thesis. The thesis deals with the precautionary evacuation of an industrial facility's workforce threatened by a radiological release from a nuclear power plant nearby. The issue of deferring intervention decisions until additional information is available is addressed. Furthermore, interventions in industrial areas with a concentration of chemical and petrochemical plants form part of this study.

  10. Proceedings of the ICTSS 2012 PhD Workshop - Preface

    Nielsen, Brian; Weise, Carsten


    their thesis work and receive constructive feedback from experts in the field as well as from peers. Also it is an opportunity for researchers to get an insight into new research topics in the field. Ph.D. students at any stage of their doctoral studies may participate. Seven abstracts were submitted......, theoretic, and practical challenges of testing software systems, including communication protocols, services, distributed platforms, middleware, embedded systems, and security infrastructures. The aims of the ICTSS Doctoral Workshop is to provide a forum for PhD students to present preliminary results and...

  11. Ph.D. shortage

    The late 1990s will see a shortage of Ph.D. graduates, according to the Association of American Universities, Washington, D.C. AAU's new comprehensive study, “The Ph.D. Shortage: The Federal Role,” reports that competition for new Ph.D.s is already intense and can only intensify because demand is greater than supply in both academic and nonacademic markets.Doctoral education plays an increasingly important role in U.S. research and development programs. Students have a pivotal part in doing research and enriching it with new ideas. The AAU report says that graduate students are “major determinants of the creativity and productivity of U.S. academic research, the source of more than 50% of the nation's basic research.’ The market for doctoral education extends beyond the university. In 1985, about 43% of all Ph.D.s employed in this country were working outside higher education; the demand for doctorate recipients in nonacademic sectors continues to grow.

  12. Choosing Thesis Juries: The Costs of Taking a Strict Line on Conflicts of Interest

    Williams-Jones, Bryn


    Full Text Available This case study examines the conflicts of interest (COI that can arise in the selection of jury members to evaluate a PhD thesis, and the costs (time, personnel, expertise associated with trying to avoid COI.

  13. Thesis Preparation Manual


    "This Thesis Preparation Manual has been written to provide you with format and procedure guidance for preparing and processing your thesis at the Naval Postgraduate School. It covers both unclassified and classified theses. All theses and thesis technical reports must be prepared in accordance with these guidelines. Please note that this manual is not written in the thesis format." form the Foreword

  14. Teaching the Thesis

    Carroll, Joyce Armstrong


    Writing a good thesis provides a successful foundation for composing an essay. Teaching how to do that, however, is quite another matter. Teachers often say to students, "Find a thesis," or "Get a thesis," or "Bring in a thesis statement tomorrow," as if students could order one like a pizza, command it like a pet pooch, or grasp one out of thin…

  15. Constructing Your Thesis

    Ryan, Anne; Walsh, Tony


    This chapter explores a number of questions most commonly asked by students as they embark on writing a thesis: •What is a thesis? •How is a thesis structured? •How do I select a thesis topic? •How do I formulate a research question or hypothesis? •How can I be sure I take an objective angle in writing my thesis? •How do I start my thesis? •What is theory? •What can I expect from my supervisor? •What will I learn from writing a thesis?

  16. Industrial PhD report: Sustainable Innovation

    Olesen, Gitte Gylling Hammershøj


    Erhvervs PhD rapport udarbejdet i tilknytning til Erhvervs PhD kurset der er obligatorisk for Erhvervs PhD studerende. Rapporten omhandler relationer melllem den akademiske verden og industrien i sammenhæng med PhD projektet, betragtet og analyseret gennem teori om bæredygtig innovation.......Erhvervs PhD rapport udarbejdet i tilknytning til Erhvervs PhD kurset der er obligatorisk for Erhvervs PhD studerende. Rapporten omhandler relationer melllem den akademiske verden og industrien i sammenhæng med PhD projektet, betragtet og analyseret gennem teori om bæredygtig innovation....

  17. Riccardo Ranieri (left) receives the 2003 CMS Thesis Award from Lorenzo Foà, the chairperson of the CMS collaboration board, at the awards ceremony

    Maximilien Brice


    2003 CMS Thesis Award was presented to Riccardo Ranieri for his PhD thesis "Trigger selection of WH -> bb (bar) with CMS". Ranieri received his PhD from the University of Florence and was supervised by Carlo Civinini.

  18. Rinaldo Paar, PhD in Technical Sciences

    Zdravko Kapović


    Full Text Available Rinaldo Paar defended his PhD thesis Geospatial Databases of Objects in the Highway Management System of the Republic of Croatia at the Faculty of Geodesy, University of Zagreb on 29 June 2010. His thesis supervisor was Prof. Dr. Zdravko Kapović. The Examining Committee comprised Prof. Dr. Gorana Novaković, Prof. Dr. Zdravko Kapović, Prof. Dr. Marko Džapo (all of the Faculty of Geodesy and Prof. Dr. Zlatko Šavor and Prof. Dr. Ljudevit Herceg of the Faculty of Civil Engineering, University of Zagreb.

  19. Andrija Krtalić, PhD in Technical Sciences

    Miljenko Lapaine


    Full Text Available Andrija Krtalić successfully defended his PhD thesis Decision Support System in Conditions of Uncertainty in Demining Activities Based on Remote Sensing Methods at the Faculty of Geodesy, University of Zagreb on 11 July 2011. The thesis was examined by an Examining Committee composed of Prof. Emer. Nedjeljko Frančula, Prof. Dr. Miljenko Lapaine, Prof. Dr. Renata Pernar (Faculty of Forestry, University of Zagreb, Prof. Dr. Hrvoje Gold (Faculty of Traffic Sciences in Zagreb and Prof. Dr. Milan Bajić (supervisor.

  20. Articulating Expectations for PhD Candidature upon Commencement: Ensuring Supervisor/Student "Best Fit"

    Moxham, Lorna; Dwyer, Trudy; Reid-Searl, Kerry


    The journey towards completion of a PhD is a bumpy one for many. One of the major factors that influence successful and on-time thesis completion is the relationship that the PhD candidate has with her or his supervisor. This paper presents results from research undertaken using a 12-item survey to collect data from a purposive sample: PhD…

  1. Rainfall-runoff modeling in arid areas

    Abushandi, Eyad


    The Wadi Dhuliel catchment/ North east Jordan, as any other arid area has distinctive hydrological features with limited water resources. The hydrological regime is characterized by high variability of temporal and spatial rainfall distributions, flash floods, absence of base flow, and high rates of evapotranspiration. The aim of this Ph.D. thesis was to apply lumped and distributed models to simulate stream flow in the Wadi Dhuliel arid catchment. Intensive research was done to estimate the ...

  2. The Tractable Cognition thesis

    Rooij, I.J.E.I. van


    The recognition that human minds/brains are finite systems with limited resources for computation has led some researchers to advance the Tractable Cognition thesis: Human cognitive capacities are constrained by computational tractability. This thesis, if true, serves cognitive psychology by constra

  3. The Tractable Cognition Thesis

    van Rooij, Iris


    The recognition that human minds/brains are finite systems with limited resources for computation has led some researchers to advance the "Tractable Cognition thesis": Human cognitive capacities are constrained by computational tractability. This thesis, if true, serves cognitive psychology by constraining the space of computational-level theories…

  4. Feynman's thesis: A new approach to quantum theory

    It is not usual for someone to write a book on someone else's Ph.D. thesis, but then Feynman was not a usual physicist. He was without doubt one of the most original physicists of the twentieth century, who has strongly influenced the developments in quantum field theory through his many ingenious contributions. Path integral approach to quantum theories is one such contribution which pervades almost all areas of physics. What is astonishing is that he developed this idea as a graduate student for his Ph.D. thesis which has been printed, for the first time, in the present book along with two other related articles. The early developments in quantum theory, by Heisenberg and Schroedinger, were based on the Hamiltonian formulation, where one starts with the Hamiltonian description of a classical system and then promotes the classical observables to noncommuting quantum operators. However, Dirac had already stressed in an article in 1932 (this article is also reproduced in the present book) that the Lagrangian is more fundamental than the Hamiltonian, at least from the point of view of relativistic invariance and he wondered how the Lagrangian may enter into the quantum description. He had developed this idea through his 'transformation matrix' theory and had even hinted on how the action of the classical theory may enter such a description. However, although the brief paper by Dirac contained the basic essential ideas, it did not fully develop the idea of a Lagrangian description in detail in the functional language. Feynman, on the other hand, was interested in the electromagnetic interactions of the electron from a completely different point of view rooted in a theory involving action-at-a-distance. His theory (along with John Wheeler) did not have a Hamiltonian description and, in order to quantize such a theory, he needed an alternative formulation of quantum mechanics. When the article by Dirac was brought to his attention, he immediately realized what he was

  5. The Competitors: violent women protagonists in popular cinema - a creative and critical thesis

    Greenberg, Ruth


    The Competitors Violent Women Protagonists in Popular Cinema: A Creative and Critical Thesis is a practice based PhD thesis in creative and critical writing. This research comprises an original feature length screenplay and an accompanying critical thesis. The screenplay, The Competitors, is a dystopian western set in Britain 2053 and follows two women on a journey through a brutal landscape. The subjects of competition and violence are at the centre of this creative work, in particular ...

  6. Master Thesis Chao Xu

    Chao, Xu Jr


    This master thesis deals with the research question of the changes of terrorism, especially after “9, 11”, what the role of mass media plays and how internet is changing terrorism both in international society and China so far.

  7. Lamm Thesis Handbook

    Lamm, D.


    This guide has been prepared for use by Systems Management students to assist them in the research and writing of the master's thesis. It outlines the specific steps necessary to successfully complete a thesis of high quality. It has been written specifically for you, the student. As appropriate, this guide will be revised to reflect changes in school policy, advances in research methodology, availability of new resources and the accumulated experience of both students and faculty. S...

  8. Dražen Tutić, PhD in Technical Sciences

    Miljenko Lapaine


    Full Text Available Dražen Tutić defended his PhD thesis Stereographic and Other Conformal Map Projections  for Croatia at the Faculty of Geodesy of the University of Zagreb on August 4, 2009. The thesis was evaluated by the Committee: Prof. Emeritus Nedjeljko Frančula, Prof. Dr. Miljenko Lapaine (mentor and Prof. Dr. Dušan Petrovič from the Faculty of Civil and Geodetic Engineering of the University of Ljubljana.

  9. THESIS9, Version Oct85

    Frazier, Larry; Carlsen, David D.


    This example of a thesis explains how to effectively use the THESIS9 thesis preparation package. This example includes an index to improve its usefulness as documentation. However, an index is not part of accepted thesis format. It is intended that the THESIS9 commands produce all requirements of the NPS Thesis Manual dated 5/85. In addition they provide some features that simplify thesis preparation. All headings, the table of contents, figures, tables and references ...

  10. Modern Approach in Management and Noise Control in Urban Areas

    Hadzi-Nikolova, Marija


    PhD thesis presents identification and analysis of noise sources in the city of Stip (as a representative for a small urban center with a dynamic development, whose noise dispersion model can be applied in other similar urban centers). Methodology for modern technologies application in management and noise control in urban areas is developed based on generated noise maps and conflicting noise maps. For this porpose, two-year noise level monitoring on strategic measurement points was performed...

  11. ATLAS Thesis Awards 2015

    Biondi, Silvia


    Winners of the ATLAS Thesis Award were presented with certificates and glass cubes during a ceremony on Thursday 25 February. The winners also presented their work in front of members of the ATLAS Collaboration. Winners: Javier Montejo Berlingen, Barcelona (Spain), Ruth Pöttgen, Mainz (Germany), Nils Ruthmann, Freiburg (Germany), and Steven Schramm, Toronto (Canada).

  12. Going beyond the Thesis

    Smith, Andrew C.


    Most every writing teacher can relate to the curse of reading yet another incoherent essay, the contents of which resemble an unorganized junk drawer of thoughts. Such essays cry out for a main idea. The remedy is a thesis, and teachers rightly take pains to help students discover this. Yet in spite of this, writing teachers ought to bear in mind…

  13. Writing a Thesis Differently

    Honan, Eileen; Bright, David


    In this paper we explore the contributions that Deleuze and Guattari have made to thinking/writing language and how these ideas can be put to work in producing a doctoral thesis. We contribute to the field of work within what Patti Lather and Elizabeth St Pierre have called the "post-qualitative" movement, where researchers attempt to…

  14. The Las Vegas Thesis

    Sughrua, William


    Following "reflexive ethnography" and utilizing an approach of "performative narrative" and "layered text", this article explores how Bachelor of Arts students in the Teaching of English as a Foreign Language program at a public university in Mexico successfully manage the writing of an inductive-oriented thesis in English by resisting…

  15. On Einstein's Doctoral Thesis

    Straumann, N


    Einstein's thesis ``A New Determination of Molecular Dimensions'' was the second of his five celebrated papers in 1905. Although it is -- thanks to its widespread practical applications -- the most quoted of his papers, it is less known than the other four. The main aim of the talk is to show what exactly Einstein did in his dissertation. As an important application of the theoretical results for the viscosity and diffusion of solutions, he got (after eliminating a calculational error) an excellent value for the Avogadro number from data for sugar dissolved in water. This was in agreement with the value he and Planck had obtained from the black-body radiation. Two weeks after he finished the `Doktorarbeit', Einstein submitted his paper on Brownian motion, in which the diffusion formula of his thesis plays a crucial role.

  16. [Albert Schwietzer's doctoral thesis].

    Gorn, M F


    A review on Albert Schweitzer's doctoral thesis "The psychiatric study on Jesus" and his analysis of the delirium of persecution, megalomania and hallucination in order to refuse different authors hypothesis about the Jesus, psychosis or paranoia. The author highlights the symbolism of Schweitzer's decision for studying medicine and dedicating his life and efforts to the full of need men of Africa so the importance of his philosophic studies on the western culture. PMID:11640683

  17. The origin and evolution of sulfur in an Archean volcano-sedimentary basin, Deer Lake area, Minnesota. M.S. Thesis

    Nicol, D. L.


    Rocks of the Deer Lake area, northcentral Minnesota, consist of Archean (age greater than 2.6 billion years) metasediments and metavolcanics intruded by mafic layered sills. Geologic and sulfur isotopic data suggest that sulfides in the sediments are bacteriogenic, having formed in response to the activity of sulfate reducing bacteria during diagenesis. Deposition of the sediments appears to have occurred in a deep marine basin with restricted circulation of sea water. The bulk of the sulfur in the igneous rocks is of deep seated origin, but basal contacts of the sills show evidence of assimilation of biogenic sulfur from the intruded sediments. This assimilation of biogenic sulfur is the primary geochemical control of local Cu-Ni sulfide mineralization.

  18. Urbanism PhD Research 2008 - 2010

    Van der Hoeven, F.D.; Brand, N.; Van der Burg, L.; Çalışkan, O.; Tan, E.R.; Wang, C.-Y.; Zhou, J.


    To ensure the quality of the Ph.D. research the Department introduced a special procedure for periodic evaluation: after a period of nine months the potential Ph.D. candidates are asked to present their research design, theoretical framework and methodological approach to the members of the Departme

  19. Diversity in Collaborative Research Communities: A Multicultural, Multidisciplinary Thesis Writing Group in Public Health

    Guerin, Cally; Xafis, Vicki; Doda, Diana V.; Gillam, Marianne H.; Larg, Allison J.; Luckner, Helene; Jahan, Nasreen; Widayati, Aris; Xu, Chuangzhou


    Writing groups for doctoral students are generally agreed to provide valuable learning spaces for Ph.D. candidates. Here an academic developer and the eight members of a writing group formed in a Discipline of Public Health provide an account of their experiences of collaborating in a multicultural, multidisciplinary thesis writing group. We…

  20. Creating entrepreneurial networks : academic entrepreneurship, mobility and collaboration during PhD education

    Bienkowska, Dzamila; Klofsten, Magnus


    Network-building activities of PhD students are an important area of study in furthering our understanding of academic entrepreneurship. This paper focuses on PhD students’ participation in network-building activities defined as mobility and collaboration, as well as own interest in and perceived grade of support for commercialisation from various levels of the university hierarchy. The results of a large-scale survey (of 1,126 PhD students at Linköping University, Sweden, 41% response rate) ...

  1. The Price of a Thesis

    Pad+ma skyabs


    Full Text Available "Ring…ring…" bleated a mobile phone, waking Lha mo, a student in the Tibetan Department at a well-known nationalities university. She raised her head languidly and looked around the dorm room. Her roommates were applying various cosmetics and lotions to their faces, getting ready for class. The warm sun heated her bed. She slowly turned her head to the right and gazed at a small picture of a young Chinese movie star pasted on the wall by her bed. He was wearing a shirt that exposed his skin, which seemed as white as flour smeared on a cutting board beneath a ball of dough. Nearby was a panda doll wearing a suit of red clothes that made it resemble a sleeping guard. She was suddenly overwhelmed by nostalgia. Lha mo came from an area where Tibetan was rarely taught. Sometimes she hated herself for being Tibetan. Lha mo would soon leave school and was required to write a thesis. Because her written Tibetan was very poor, she resolved to use Chinese, and spent two weeks writing a few lines in her notebook. What she wrote had many grammar mistakes and she quickly and angrily ripped the pages into pieces. She agonized about her situation and didn't know what to do. Then she heard the good news that a thesis could be purchased in Room 304, East Second Street. The problem was that it cost 2,000 yuan, which was far too expensive for her. She only received 1,000 yuan a month from her family, half of which was for food and the other half went to meet the cost of clothes and other expenses. She just didn't have the money to buy the thesis. ...

  2. Method for assessing consolidated coastal tourist areas and urban regeneration. La costa del sol occidental

    Gallardo Ramírez, Cristina


    The research presented in this abstract, which is in an initial phase, forms part of a future PhD thesis whose objective is the definition of a Methodology to assessment and integral regeneration of the Mediterranean coastal tourist areas in Spain, transformed since the start of tourism as massive activity in the mid-twentieth century. The base of this research is the fact that historic city centres, neighborhoods or brownfields have been the focus of european and national urban regeneration ...

  3. Education of MSc and PhD Students in Fluid Power and Mechatronics at DTU

    Conrad, Finn


    The paper deals with education of MSc and PhD students in engineering areas fluid power and mechatronics at the Technical Univ of Denmark, DTU, Lyngby. The new education structure and programs for MSc and PhD students adapted to the change and development of technologies. Focus is on two of twent...... industrial enterprises into account. Projects are included covering mathematical modelling, simulation, analysis, experiments, implementation and prototyping....

  4. Phd dissertation on: Effects of an expressive writing intervention in a nationwide sample of breast cancer patients

    Jensen-Johansen, Mikael Birkelund


    This PhD thesis consists of four original papers, including a systematic review and meta-analysis, a pilot-study, and the to date largest nationwide randomized controlled trial examining the effects of expressive writing intervention (EWI) on psychological adjustment, somatic symptoms, and health...

  5. Interaction in PhD supervision

    Kobayashi, Sofie; Grout, Brian William Wilson; Rump, Camilla Østerberg

    This paper contains an analysis of a single supervision session, undertaken with the aim of identifying how learning opportunities might be created for a PhD student. The supervision session concerned methodologies to be employed in a PhD study related to storm water management and included the Ph...... learning opportunity is created for the PhD student as a participant in the academic discussion with her supervisors about the research methodologies. The involvement of multiple supervisors appears to enrich the learning environment and help create learning opportunity....

  6. Robert Lončarić, PhD in Geography

    Damir Magaš


    Full Text Available On June 29, 2010, Robert Lončarić defended his PhD thesis Littoralisation of the Kvarner Islands – a Hydrogeographical Basis at the Department of Geography of the University of Zadar. Members of the Defence Committee  were Prof. Dr. Damir Magaš (mentor, Assoc. Prof. Dr. Martin Glamuzina, (Chairman and Prof. Dr. Ognjen Bonacci of the Faculty of Civil Engineering and Architecture in Split.

  7. Estimation from incomplete multinomial data. Ph.D. Thesis - Harvard Univ.

    Credeur, K. R.


    The vector of multinomial cell probabilities was estimated from incomplete data, incomplete in that it contains partially classified observations. Each such partially classified observation was observed to fall in one of two or more selected categories but was not classified further into a single category. The data were assumed to be incomplete at random. The estimation criterion was minimization of risk for quadratic loss. The estimators were the classical maximum likelihood estimate, the Bayesian posterior mode, and the posterior mean. An approximation was developed for the posterior mean. The Dirichlet, the conjugate prior for the multinomial distribution, was assumed for the prior distribution.

  8. Optical Communication with Semiconductor Laser Diode. Interim Progress Report. Ph.D. Thesis

    Davidson, Frederic; Sun, Xiaoli


    Theoretical and experimental performance limits of a free-space direct detection optical communication system were studied using a semiconductor laser diode as the optical transmitter and a silicon avalanche photodiode (APD) as the receiver photodetector. Optical systems using these components are under consideration as replacements for microwave satellite communication links. Optical pulse position modulation (PPM) was chosen as the signal format. An experimental system was constructed that used an aluminum gallium arsenide semiconductor laser diode as the transmitter and a silicon avalanche photodiode photodetector. The system used Q=4 PPM signaling at a source data rate of 25 megabits per second. The PPM signal format requires regeneration of PPM slot clock and word clock waveforms in the receiver. A nearly exact computational procedure was developed to compute receiver bit error rate without using the Gaussion approximation. A transition detector slot clock recovery system using a phase lock loop was developed and implemented. A novel word clock recovery system was also developed. It was found that the results of the nearly exact computational procedure agreed well with actual measurements of receiver performance. The receiver sensitivity achieved was the closest to the quantum limit yet reported for an optical communication system of this type.

  9. Reliable and Efficient Parallel Processing Algorithms and Architectures for Modern Signal Processing. Ph.D. Thesis

    Liu, Kuojuey Ray


    Least-squares (LS) estimations and spectral decomposition algorithms constitute the heart of modern signal processing and communication problems. Implementations of recursive LS and spectral decomposition algorithms onto parallel processing architectures such as systolic arrays with efficient fault-tolerant schemes are the major concerns of this dissertation. There are four major results in this dissertation. First, we propose the systolic block Householder transformation with application to the recursive least-squares minimization. It is successfully implemented on a systolic array with a two-level pipelined implementation at the vector level as well as at the word level. Second, a real-time algorithm-based concurrent error detection scheme based on the residual method is proposed for the QRD RLS systolic array. The fault diagnosis, order degraded reconfiguration, and performance analysis are also considered. Third, the dynamic range, stability, error detection capability under finite-precision implementation, order degraded performance, and residual estimation under faulty situations for the QRD RLS systolic array are studied in details. Finally, we propose the use of multi-phase systolic algorithms for spectral decomposition based on the QR algorithm. Two systolic architectures, one based on triangular array and another based on rectangular array, are presented for the multiphase operations with fault-tolerant considerations. Eigenvectors and singular vectors can be easily obtained by using the multi-pase operations. Performance issues are also considered.

  10. Very long baseline interferometry applied to polar motion, relativity, and geodesy. Ph.D. thesis

    The causes and effects of diurnal polar motion are described. An algorithm was developed for modeling the effects on very long baseline interferometry observables. A selection was made between two three-station networks for monitoring polar motion. The effects of scheduling and the number of sources observed on estimated baseline errors are discussed. New hardware and software techniques in very long baseline interferometry are described

  11. Optical measurements of soot in premixed flames. Ph.D. Thesis - California Univ.

    Lyons, Valerie J.


    Two laser diagnostic techniques were used to measure soot volume fractions, number densities and soot particle radii in premixed propane/oxygen flat flames. The two techniques were two wavelength extinction, using 514.5 to 632.8 nm and 457.9 to 632.8 nm wavelength combinations, and extinction/scattering using 514.5 nm light. The flames were fuel rich and had cold gas velocities varying from 3.4 to 5.5 cm/s. Measurements were made at various heights above the sintered bronze, water colored flat flame burner with the equivalence ratio and cold gas velocity fixed. Also, measurements were made at a fixed height above the burner and fixed cold gas velocity while varying the equivalence ratio. Both laser techniques are based on the same underlying assumptions of particle size distribution and soot optical properties. Full Mie theory was used to determine the extinction coefficients and the scattering efficiencies. Temperature measurements in the flame were made using infrared radiometry and fine wire thermocouples. Good agreement between the two techniques in terms of soot particle radii, number density and volume fraction was found for intensity ratios between 0.1 and 0.8.

  12. Early impact basins and the onset of plate tectonics. Ph.D. Thesis - Maryland Univ.

    Frey, H.


    The fundamental crustal dichotomy of the Earth (high and low density crust) was established nearly 4 billion years ago. Therefore, subductable crust was concentrated at the surface of the Earth very early in its history, making possible an early onset for plate tectonics. Simple thermal history calculations spanning 1 billion years show that the basin forming impact thins the lithosphere by at least 25%, and increases the sublithosphere thermal gradients by roughly 20%. The corresponding increase in convective heat transport, combined with the highly fractured nature of the thinned basin lithosphere, suggest that lithospheric breakup or rifting occurred shortly after the formation of the basins. Conditions appropriate for early rifting persisted from some 100,000,000 years following impact. We suggest a very early stage of high temperature, fast spreading "microplate" tectonics, originating before 3.5 billion years ago, and gradually stabilizing over the Archaean into more modern large plate or Wilson Cycle tectonics.

  13. Intervention into a turbulent urban situation: A case study. Ph.D. Thesis

    Caldwell, G. M., Jr.


    The application is reported of NASA management philosophy and techniques within New Castle County, Delaware, to meet actual problems of community violence. It resulted in restructuring the county approach to problems of this nature, and development of a comprehensive system for planning, based on the NASA planning process. The method involved federal, state, and local resources with community representatives in solving the problems. The concept of a turbulent environment is presented with parallels drawn between NASA management experience and problems of management within an urban arena.

  14. Ion tracking in an electrostatic potential distribution. Ph.D. Thesis; [photomultiplier tubes

    Ross, D. P.


    An ion tracking system utilizing a single detector was designed to resolve two dimensional potential distributions in a vacuum. The ion detector consisted of a continuous dynode electron multiplier tube mounted behind a series of aperture plates. The detector was located on a track below a wedge shaped structure used to produce the desired potential distribution. A 150 volt electron beam aimed at selected regions, ionized the residual gas in the chamber. The ions were ejected from their source points by electrostatic forces causing them to drift downward toward the detector. Measurements of particle energy, detector position, and entry angle of the incoming particle flux were used to initialize a computer trajectory-tracing program. The program assumes a known theoretically calculated potential distribution near the wedge for computation of particle trajectories, providing a basis for evaluating the data. Special attention was given to characterization of the ion detector.

  15. Solid state polymerization and crystallography of polyimide precursors. Ph.D. Thesis - Va. Univ.

    Wakelyn, N. T.


    Although the production of crystallinity in a polymeric system has historically led to commerically useful properties, the polyimides, prized for their high temperature characteristics, as customarily synthesized by melt or solution casting, are amorphous. It is shown that polymide containing residual crystallinity can be synthesized by isothermal annealing of crystals of the salt of the diisopropyl ester of pyromellitic acid and phenylene diamine. The reaction is topochemical in that the geometry of the polymer product is dependent upon that of the crystalline precursor. Infrared spectroscopy reveals the presence of imide absorption in the polymer, while powder diffractometry suggests residual crystallinity. Single crystal X-ray analysis of the monomer yields a structure of chains of alternating acid and base suggesting that the monomer is amenable to polymerization with a minimum of geometrical disruption.

  16. Knowledge Management Techniques to Augment Textual CBR (PhD Thesis)

    Padmanabhan, Deepak


    The past decade had witnessed an unprecedented growth in the amount of available digital content, and its volume is expected to continue to grow the next few years. Unstructured text data generated from web and enterprise sources form a large fraction of such content. Many of these contain large volumes of reusable data such as solutions to frequently occurring problems, and general know-how that may be reused in appropriate contexts. In this work, we address issues around leveraging unstruct...

  17. Modal analysis and control of flexible manipulator arms. Ph.D. Thesis

    Neto, O. M.


    The possibility of modeling and controlling flexible manipulator arms was examined. A modal approach was used for obtaining the mathematical model and control techniques. The arm model was represented mathematically by a state space description defined in terms of joint angles and mode amplitudes obtained from truncation on the distributed systems, and included the motion of a two link two joint arm. Three basic techniques were used for controlling the system: pole allocation with gains obtained from the rigid system with interjoint feedbacks, Simon-Mitter algorithm for pole allocation, and sensitivity analysis with respect to parameter variations. An improvement in arm bandwidth was obtained. Optimization of some geometric parameters was undertaken to maximize bandwidth for various payload sizes and programmed tasks. The controlled system is examined under constant gains and using the nonlinear model for simulations following a time varying state trajectory.

  18. Kinetic model for the vibrational energy exchange in flowing molecular gas mixtures. Ph.D. Thesis

    Offenhaeuser, F.


    The present study is concerned with the development of a computational model for the description of the vibrational energy exchange in flowing gas mixtures, taking into account a given number of energy levels for each vibrational degree of freedom. It is possible to select an arbitrary number of energy levels. The presented model uses values in the range from 10 to approximately 40. The distribution of energy with respect to these levels can differ from the equilibrium distribution. The kinetic model developed can be employed for arbitrary gaseous mixtures with an arbitrary number of vibrational degrees of freedom for each type of gas. The application of the model to CO2-H2ON2-O2-He mixtures is discussed. The obtained relations can be utilized in a study of the suitability of radiation-related transitional processes, involving the CO2 molecule, for laser applications. It is found that the computational results provided by the model agree very well with experimental data obtained for a CO2 laser. Possibilities for the activation of a 16-micron and 14-micron laser are considered.

  19. Space Reclamation for Uncoordinated Checkpointing in Message-Passing Systems. Ph.D. Thesis

    Wang, Yi-Min


    Checkpointing and rollback recovery are techniques that can provide efficient recovery from transient process failures. In a message-passing system, the rollback of a message sender may cause the rollback of the corresponding receiver, and the system needs to roll back to a consistent set of checkpoints called recovery line. If the processes are allowed to take uncoordinated checkpoints, the above rollback propagation may result in the domino effect which prevents recovery line progression. Traditionally, only obsolete checkpoints before the global recovery line can be discarded, and the necessary and sufficient condition for identifying all garbage checkpoints has remained an open problem. A necessary and sufficient condition for achieving optimal garbage collection is derived and it is proved that the number of useful checkpoints is bounded by N(N+1)/2, where N is the number of processes. The approach is based on the maximum-sized antichain model of consistent global checkpoints and the technique of recovery line transformation and decomposition. It is also shown that, for systems requiring message logging to record in-transit messages, the same approach can be used to achieve optimal message log reclamation. As a final topic, a unifying framework is described by considering checkpoint coordination and exploiting piecewise determinism as mechanisms for bounding rollback propagation, and the applicability of the optimal garbage collection algorithm to domino-free recovery protocols is demonstrated.

  20. Best Phd thesis Prize : Statistical analysis of ALFALFA galaxies: insights in galaxy

    Papastergis, E.


    We use the rich dataset of local universe galaxies detected by the ALFALFA 21cm survey to study the statistical properties of gas-bearing galaxies. In particular, we measure the number density of galaxies as a function of their baryonic mass ("baryonic mass function") and rotational velocity ("veloc

  1. Spectrophotometric analysis of cometary nuclei from in situ observations (PhD thesis)

    Raponi, Andrea


    Topic of this work are comets, small and elusive objects that may hold great secrets about the origin of the Solar System and life on Earth, being among the most primitive objects. The method of investigation addressed in this work is the visible and infrared spectrophotometry by imaging spectrometers, designed for the observation of remote planetary atmospheres and surfaces, capable to acquire hyperspectral data with high spatial and spectral resolution. The context under which this mission moves its steps is described in the first chapter. In the second chapter the performances of the VIRTS instrument, onboard Rosetta spacecraft, are analyzed in detail. In particular the modeling of the signal to noise ratio is the main argument of this chapter. The third chapter shows simulations of possible spectra of the comet's nucleus, which are useful for both a comparison with real spectra, and for a planning of the observations. Hapke's radiative transfer model is used to invert acquired data to infer physical prope...

  2. Dynamic Analysis and Control of Lightweight Manipulators with Flexible Parallel Link Mechanisms. Ph.D. Thesis

    Lee, Jeh Won


    The objective is the theoretical analysis and the experimental verification of dynamics and control of a two link flexible manipulator with a flexible parallel link mechanism. Nonlinear equations of motion of the lightweight manipulator are derived by the Lagrangian method in symbolic form to better understand the structure of the dynamic model. The resulting equation of motion have a structure which is useful to reduce the number of terms calculated, to check correctness, or to extend the model to higher order. A manipulator with a flexible parallel link mechanism is a constrained dynamic system whose equations are sensitive to numerical integration error. This constrained system is solved using singular value decomposition of the constraint Jacobian matrix. Elastic motion is expressed by the assumed mode method. Mode shape functions of each link are chosen using the load interfaced component mode synthesis. The discrepancies between the analytical model and the experiment are explained using a simplified and a detailed finite element model.

  3. Automatic data partitioning on distributed memory multicomputers. Ph.D. Thesis

    Gupta, Manish


    Distributed-memory parallel computers are increasingly being used to provide high levels of performance for scientific applications. Unfortunately, such machines are not very easy to program. A number of research efforts seek to alleviate this problem by developing compilers that take over the task of generating communication. The communication overheads and the extent of parallelism exploited in the resulting target program are determined largely by the manner in which data is partitioned across different processors of the machine. Most of the compilers provide no assistance to the programmer in the crucial task of determining a good data partitioning scheme. A novel approach is presented, the constraints-based approach, to the problem of automatic data partitioning for numeric programs. In this approach, the compiler identifies some desirable requirements on the distribution of various arrays being referenced in each statement, based on performance considerations. These desirable requirements are referred to as constraints. For each constraint, the compiler determines a quality measure that captures its importance with respect to the performance of the program. The quality measure is obtained through static performance estimation, without actually generating the target data-parallel program with explicit communication. Each data distribution decision is taken by combining all the relevant constraints. The compiler attempts to resolve any conflicts between constraints such that the overall execution time of the parallel program is minimized. This approach has been implemented as part of a compiler called Paradigm, that accepts Fortran 77 programs, and specifies the partitioning scheme to be used for each array in the program. We have obtained results on some programs taken from the Linpack and Eispack libraries, and the Perfect Benchmarks. These results are quite promising, and demonstrate the feasibility of automatic data partitioning for a significant class of scientific application programs with regular computations.

  4. An Adaptive Technique for a Redundant-Sensor Navigation System. Ph.D. Thesis

    Chien, T. T.


    An on-line adaptive technique is developed to provide a self-contained redundant-sensor navigation system with a capability to utilize its full potentiality in reliability and performance. The gyro navigation system is modeled as a Gauss-Markov process, with degradation modes defined as changes in characteristics specified by parameters associated with the model. The adaptive system is formulated as a multistage stochastic process: (1) a detection system, (2) an identification system and (3) a compensation system. It is shown that the sufficient statistics for the partially observable process in the detection and identification system is the posterior measure of the state of degradation, conditioned on the measurement history.

  5. Numerical simulation of a compressible homogeneous, turbulent shear flow. Ph.D. Thesis

    Feiereisen, W. J.; Reynolds, W. C.; Ferziger, J. H.


    A direct, low Reynolds number, numerical simulation was performed on a homogeneous turbulent shear flow. The full compressible Navier-Stokes equations were used in a simulation on the ILLIAC IV computer with a 64,000 mesh. The flow fields generated by the code are used as an experimental data base, to examine the behavior of the Reynols stresses in this simple, compressible flow. The variation of the structure of the stresses and their dynamic equations as the character of the flow changed is emphasized. The structure of the tress tensor is more heavily dependent on the shear number and less on the fluctuating Mach number. The pressure-strain correlation tensor in the dynamic uations is directly calculated in this simulation. These correlations are decomposed into several parts, as contrasted with the traditional incompressible decomposition into two parts. The performance of existing models for the conventional terms is examined, and a model is proposed for the 'mean fluctuating' part.

  6. The Use of Efficient Broadcast Protocols in Asynchronous Distributed Systems. Ph.D. Thesis

    Schmuck, Frank Bernhard


    Reliable broadcast protocols are important tools in distributed and fault-tolerant programming. They are useful for sharing information and for maintaining replicated data in a distributed system. However, a wide range of such protocols has been proposed. These protocols differ in their fault tolerance and delivery ordering characteristics. There is a tradeoff between the cost of a broadcast protocol and how much ordering it provides. It is, therefore, desirable to employ protocols that support only a low degree of ordering whenever possible. This dissertation presents techniques for deciding how strongly ordered a protocol is necessary to solve a given application problem. It is shown that there are two distinct classes of application problems: problems that can be solved with efficient, asynchronous protocols, and problems that require global ordering. The concept of a linearization function that maps partially ordered sets of events to totally ordered histories is introduced. How to construct an asynchronous implementation that solves a given problem if a linearization function for it can be found is shown. It is proved that in general the question of whether a problem has an asynchronous solution is undecidable. Hence there exists no general algorithm that would automatically construct a suitable linearization function for a given problem. Therefore, an important subclass of problems that have certain commutativity properties are considered. Techniques for constructing asynchronous implementations for this class are presented. These techniques are useful for constructing efficient asynchronous implementations for a broad range of practical problems.

  7. Energetic neutrinos from heavy-neutralino annihilation in the Sun. Ph.D. Thesis

    Kamionkowski, Marc


    Neutralinos may be captured in the sun and annihilated therein producing high-energy neutrinos. Present limits on the flux of such neutrinos from underground detectors such as IMB and Kamiokande 2 may be used to rule out certain supersymmetric dark matter candidates, while in many other supersymmetric models the rates are large enough that if neutralinos do reside in the galactic halo, observation of a neutrino signal may be possible in the near future. Neutralinos that are either nearly pure Higgsino or a Higgsino/gaugino combination are generally captured in the sun by coherent scattering off nuclei via exchange of the lightest Higgs boson. If the squark mass is not much greater than the neutralino mass, then capture of neutralinos that are primarily gaugino occurs predominantly by spin-dependent scattering off hydrogen in the sun. The neutrino signal from annihilation of WIMPs with masses in the range of 80 to 1000 GeV in the sun should generally be stronger than that from weakly interacting massive particle (WIMP) annihilation in the earth, and detection rates for mixed-state neutralinos are generally higher than those for Higgsinos or gauginos.

  8. BRST quantization of field theories. Resume of Ph.D thesis

    The resume contains five chapters and a reference list. list. The chapters are: 1. Introduction; 2. BRST quantization of gauge theories, with 2.1: Lagrangian BRST quantization; 2.2: Hamiltonian BRST quantization; 3. The BRST quantization of systems with class II constrains by introduction of extra-variables, with 3.1: Transformation of original system in a class I system on the same phase space; 3.2 Construction of single parameter family of class I systems; 3.3: BRST quantization of class I families; 3.4: Lagrangian approach of a class I family; 4. Applications for field theories, with 4.1: Massive Yang-Mills fields; 4.2: Massive Abelian p-forms; 5. Conclusions. 91 refs

  9. Performance Evaluation and Modeling Techniques for Parallel Processors. Ph.D. Thesis

    Dimpsey, Robert Tod


    In practice, the performance evaluation of supercomputers is still substantially driven by singlepoint estimates of metrics (e.g., MFLOPS) obtained by running characteristic benchmarks or workloads. With the rapid increase in the use of time-shared multiprogramming in these systems, such measurements are clearly inadequate. This is because multiprogramming and system overhead, as well as other degradations in performance due to time varying characteristics of workloads, are not taken into account. In multiprogrammed environments, multiple jobs and users can dramatically increase the amount of system overhead and degrade the performance of the machine. Performance techniques, such as benchmarking, which characterize performance on a dedicated machine ignore this major component of true computer performance. Due to the complexity of analysis, there has been little work done in analyzing, modeling, and predicting the performance of applications in multiprogrammed environments. This is especially true for parallel processors, where the costs and benefits of multi-user workloads are exacerbated. While some may claim that the issue of multiprogramming is not a viable one in the supercomputer market, experience shows otherwise. Even in recent massively parallel machines, multiprogramming is a key component. It has even been claimed that a partial cause of the demise of the CM2 was the fact that it did not efficiently support time-sharing. In the same paper, Gordon Bell postulates that, multicomputers will evolve to multiprocessors in order to support efficient multiprogramming. Therefore, it is clear that parallel processors of the future will be required to offer the user a time-shared environment with reasonable response times for the applications. In this type of environment, the most important performance metric is the completion of response time of a given application. However, there are a few evaluation efforts addressing this issue.

  10. Electrical properties of materials for elevated temperature resistance strain gage application. Ph.D. Thesis

    The objective was to study the electrical resistances of materials that are potentially useful as resistance strain gages at 1000 C. Transition metal carbides and nitrides, boron carbide and silicon carbide were selected for the experimental phase of this research. Due to their low temperature coefficient of resistance and good stability, TiC, ZrC, B sub 4 C and beta-SiC are suggested as good candidates for high temperature resistance strain gage applications

  11. Dynamic substructuring by the boundary flexibility vector method of component mode synthesis. Ph.D. Thesis

    Abdallah, Ayman Ahmed


    Component mode synthesis (CMS) is a method of dynamic analysis, for structures having a large number of degrees of freedom (DOF). These structures often required lengthy computer CPU time and large computer memory resources, if solved directly by the finite-element method (FEM). In CMS, the structure is divided into independent components in which the DOF are defined by a set of generalized coordinates defined by displacement shapes. The number of the generalized coordinates are much less than the original number of physical DOF, in the component. The displacement shapes are used to transform the component property matrices and any applied external loads, to a reduced system of coordinates. Reduced system property matrices are assembled, and any type of dynamic analysis is carried out in the reduced coordinate system. Any obtained results are back transformed to the original component coordinate systems. In all conventional methods of CMS, the mode shapes used for components are dynamic mode shapes, supplemented by static deflected shapes. Historically, all the dynamic mode shapes used in conventional CMS are the natural modes (eigenvectors) of components. A new method of CMS, namely the boundary flexibility vector method of CMS, is presented. The method provides for the incorporation of a set of static Ritz vectors, referred to as boundary flexibility vectors, as a replacement and/or supplement to conventional eigenvectors, as displacement shapes for components. The generation of these vectors does not require the solution of a costly eigenvalue problem, as in the case of natural modes in conventional CMS, and hence a substantial saving in CPU time can be achieved. The boundary flexibility vectors are generated from flexibility (or stiffness) properties of components. The formulation presented is for both free and fixed-interface components, and for both the free and forced vibration problems. Free and forced vibration numerical examples are presented to verify the accuracy of the method and the saving in CPU time. Compared to conventional methods of CMS, the results indicate that by using the new method, more accurate results can be obtained with a substantial saving in CPU time.

  12. An HP Adaptive Discontinuous Galerkin Method for Hyperbolic Conservation Laws. Ph.D. Thesis

    Bey, Kim S.


    This dissertation addresses various issues for model classes of hyperbolic conservation laws. The basic approach developed in this work employs a new family of adaptive, hp-version, finite element methods based on a special discontinuous Galerkin formulation for hyperbolic problems. The discontinuous Galerkin formulation admits high-order local approximations on domains of quite general geometry, while providing a natural framework for finite element approximations and for theoretical developments. The use of hp-versions of the finite element method makes possible exponentially convergent schemes with very high accuracies in certain cases; the use of adaptive hp-schemes allows h-refinement in regions of low regularity and p-enrichment to deliver high accuracy, while keeping problem sizes manageable and dramatically smaller than many conventional approaches. The use of discontinuous Galerkin methods is uncommon in applications, but the methods rest on a reasonable mathematical basis for low-order cases and has local approximation features that can be exploited to produce very efficient schemes, especially in a parallel, multiprocessor environment. The place of this work is to first and primarily focus on a model class of linear hyperbolic conservation laws for which concrete mathematical results, methodologies, error estimates, convergence criteria, and parallel adaptive strategies can be developed, and to then briefly explore some extensions to more general cases. Next, we provide preliminaries to the study and a review of some aspects of the theory of hyperbolic conservation laws. We also provide a review of relevant literature on this subject and on the numerical analysis of these types of problems.

  13. Design of passive piezoelectric damping for space structures. Final Report Ph.D. Thesis

    Hagood, Nesbitt W., IV; Aldrich, Jack B.; Vonflotow, Andreas H.


    Passive damping of structural dynamics using piezoceramic electromechanical energy conversion and passive electrical networks is a relatively recent concept with little implementation experience base. This report describes an implementation case study, starting from conceptual design and technique selection, through detailed component design and testing to simulation on the structure to be damped. About 0.5kg. of piezoelectric material was employed to damp the ASTREX testbed, a 500kg structure. Emphasis was placed upon designing the damping to enable high bandwidth robust feedback control. Resistive piezoelectric shunting provided the necessary broadband damping. The piezoelectric element was incorporated into a mechanically-tuned vibration absorber in order to concentrate damping into the 30 to 40 Hz frequency modes at the rolloff region of the proposed compensator. A prototype of a steel flex-tensional motion amplification device was built and tested. The effective stiffness and damping of the flex-tensional device was experimentally verified. When six of these effective springs are placed in an orthogonal configuration, strain energy is absorbed from all six degrees of freedom of a 90kg. mass. A NASTRAN finite element model of the testbed was modified to include the six-spring damping system. An analytical model was developed for the spring in order to see how the flex-tensional device and piezoelectric dimensions effect the critical stress and strain energy distribution throughout the component. Simulation of the testbed demonstrated the damping levels achievable in the completed system.

  14. Visible-infrared remote-sensing model and applications for ocean waters. Ph.D. Thesis

    Lee, Zhongping


    Remote sensing has become important in the ocean sciences, especially for research involving large spatial scales. To estimate the in-water constituents through remote sensing, whether carried out by satellite or airplane, the signal emitted from beneath the sea surface, the so called water-leaving radiance (L(w)), is of prime importance. The magnitude of L(w) depends on two terms: one is the intensity of the solar input, and the other is the reflectance of the in-water constituents. The ratio of the water-leaving radiance to the downwelling irradiance (E(d)) above the sear surface (remote-sensing reflectance, R(sub rs)) is independent of the intensity of the irradiance input, and is largely a function of the optical properties of the in-water constituents. In this work, a model is developed to interpret r(sub rs) for ocean water in the visible-infrared range. In addition to terms for the radiance scattered from molecules and particles, the model includes terms that describe contributions from bottom reflectance, fluorescence of gelbstoff or colored dissolved organic matter (CDOM), and water Raman scattering. By using this model, the measured R(sub rs) of waters from the West Florida Shelf to the Mississippi River plume, which covered a (concentration of chlorophyll a) range of 0.07 - 50 mg/cu m, were well interpreted. The average percentage difference (a.p.d.) between the measured and modeled R(sub rs) is 3.4%, and, for the shallow waters, the model-required water depth is within 10% of the chart depth. Simple mathematical simulations for the phytoplankton pigment absorption coefficient (a(sub theta)) are suggested for using the R(sub rs) model. The inverse problem of R(sub rs), which is to analytically derive the in-water constituents from R(sub rs) data alone, can be solved using the a(sub theta) functions without prior knowledge of the in-water optical properties. More importantly, this method avoids problems associated with a need for knowledge of the shape and value of the chlorophyll-specific absorption coefficient. The simulation was tested for a wide range of water types, including waters from Monterey Bay, the West Florida Shelf, and the Mississippi River plume. Using the simulation, the R(sub rs)-derived in-water absorption coefficients were consistent with the values from in-water measurements (r(exp 2) greater than 0.94, slope approximately 1.0). In the remote-sensing applications, a new approach is suggested for the estimation of primary production based on remote sensing. Using this approach, the calculated primary production (PP) values based upon remotely sensed data were very close to the measured values for the euphotic zone (r(exp 2) = 0.95, slope 1.26, and 32% average difference), while traditional, pigment-based PP model provided values only one-third the size of the measured data. This indicates a potential to significantly improve the accuracy of the estimation of primary production based upon remote sensing.

  15. Equalization and detection for digital communication over nonlinear bandlimited satellite communication channels. Ph.D. Thesis

    Gutierrez, Alberto, Jr.


    This dissertation evaluates receiver-based methods for mitigating the effects due to nonlinear bandlimited signal distortion present in high data rate satellite channels. The effects of the nonlinear bandlimited distortion is illustrated for digitally modulated signals. A lucid development of the low-pass Volterra discrete time model for a nonlinear communication channel is presented. In addition, finite-state machine models are explicitly developed for a nonlinear bandlimited satellite channel. A nonlinear fixed equalizer based on Volterra series has previously been studied for compensation of noiseless signal distortion due to a nonlinear satellite channel. This dissertation studies adaptive Volterra equalizers on a downlink-limited nonlinear bandlimited satellite channel. We employ as figure of merits performance in the mean-square error and probability of error senses. In addition, a receiver consisting of a fractionally-spaced equalizer (FSE) followed by a Volterra equalizer (FSE-Volterra) is found to give improvement beyond that gained by the Volterra equalizer. Significant probability of error performance improvement is found for multilevel modulation schemes. Also, it is found that probability of error improvement is more significant for modulation schemes, constant amplitude and multilevel, which require higher signal to noise ratios (i.e., higher modulation orders) for reliable operation. The maximum likelihood sequence detection (MLSD) receiver for a nonlinear satellite channel, a bank of matched filters followed by a Viterbi detector, serves as a probability of error lower bound for the Volterra and FSE-Volterra equalizers. However, this receiver has not been evaluated for a specific satellite channel. In this work, an MLSD receiver is evaluated for a specific downlink-limited satellite channel. Because of the bank of matched filters, the MLSD receiver may be high in complexity. Consequently, the probability of error performance of a more practical suboptimal MLSD receiver, requiring only a single receive filter, is evaluated.

  16. Ph.D. Thesis: Chiral Effective Field Theory Beyond the Power-Counting Regime

    Hall, Jonathan M M


    Novel techniques are presented, which identify the power-counting regime (PCR) of chiral effective field theory, and allow the use of lattice quantum chromodynamics results that extend outside the PCR. By analyzing the renormalization of low-energy coefficients of the chiral expansion of the nucleon mass, the existence of an optimal regularization scale is realized. The techniques developed for the nucleon mass renormalization are then applied to a test case: performing a chiral extrapolation without prior phenomenological bias. The robustness of the procedure for obtaining an optimal regularization scale and performing a reliable chiral extrapolation is confirmed. The procedure developed is then applied to the magnetic moment and the electric charge radius of the nucleon. The consistency of the results for the value of the optimal regularization scale provides strong evidence for the existence of an intrinsic energy scale in the nucleon-pion interaction.

  17. Anode power in a quasi-steady MPD thruster. Ph.D. Thesis

    Saber, A. J.


    Local anode heat flux in a quasi-steady MPD thruster is measured by thermocouples attached to the inside surface of a shell anode. Over a range of arc currents J from 5.5 to 44 kiloamperes and argon propellant mass flows m from 1 to 48 g/sec, with the ratio J2/m held constant, the fraction of arc power deposited in the anode is found to decrease with increasing arc power. Specifically, this anode power fraction decreases from 50% at 200 kW arc power, to 10% at 20 MW. In an effort to account for this functional behavior, the current density, plasma potential, and electron temperature in the plasma adjacent to the anode are measured with probes, and the results are used in a theoretical anode heat flux model. The model asserts that energy exchange between electrons and heavy particles in the plasma near the anode occur over distances greater than the anode sheath thickness.

  18. Mercury Oxidation over Selective Catalytic Reduction (SCR) Catalysts - Ph.d. thesis Karin Madsen

    Madsen, Karin

    The vanadium-based SCR catalyst used for NOx-control promotes the oxidation of elemental mercury Hg0 to Hg2+ in flue gases from coal-fired power plants. Hg2+ is water soluble and can effectively be captured in a wet scrubber. This means that the combination of an SCR with a wet FGD can offer...... an effective control option for mercury. Laboratory experiments have been carried out to quantify the Hg0 oxidation that can be achieved over commercial SCR catalysts for different gas compositions, operating conditions and catalyst types. The following three net reactions have been identified as relevant...... for the mercury chemistry over the SCR: R1. 2 HCl + Hg0 + 1/2 O2 ↔ HgCl2 + H2O R2. 2 NH3 + 3 HgCl2 ↔ N2 + 3 Hg0 + 6 HCl R3. 2 NO + 2 NH3 + 1/2 O2 ↔ 2 N2 + 3 H2O where reaction R1 is the oxidation of Hg0 by HCl, reaction R2 is the reduction of HgCl2 by NH3 and reaction R3 is the DeNOx reaction. The importance...

  19. Unidirectional fibers and polyurethane elastomer matrix based composites synthesis and properties. Ph.D. Thesis

    Chakar, A.


    A study of the properties and manufacturing techniques for long-fiber reinforced elastomeric composites for flexible and damping structural materials is presented. Attention is given to the usage of polyurethane in the matrix to obtain plastic elastomeric matrices and vitreous transition temperatures which vary from -80 C to 10 C, as well as assure good fiber adhesion. Various polyurethane formulations synthesized from diisocyanate prepolymers are examined in terms of mechanical and thermal properties. The principal reinforcing fiber selected is a unidirectional glass cloth.

  20. The isotropic condition of energetic particles emitted from a large solar flare. Ph.D. Thesis

    Spalding, J.


    Isotope abundance ratios for 5 to 50 MeV/nuc nuclei from a large solar flare were measured. The measurements were made by the heavy isotope spectrometer telescope (HIST) on the ISEE-3 satellite orbiting the Sun near an Earth-Sun liberation point approximately one million miles sunward of the Earth. Finite values for the isotope abundance ratios C-13/C-12, N-15/N-14, O-18/O-16, Ne-22/Ne-20, Mg-25/Mg-24, and Mg-26/Mg-24, and upper limits for the isotope abundance ratios He-3/He-4, C-14/C-12, O-17/O-16 and Ne-21/Ne-20 were reported. Element abundances and spectra were measured to compare the flare with other reported flares. The flare is a typical large flare with low Fe/O abundance or = to 0.1). For C-13/C-12, N-15/N-14, O-18/O-16, Mg-25/Mg-24 and Mg-26/Mg-24 isotope abundance ratios agree with the solar system abundance ratios. Measurement for Ne-22/Ne-20 agree with the isotopic composition of the meteoritic component neon-A.

  1. Oxygen diffusion in alpha-Al2O3. Ph.D. Thesis

    Cawley, J. D.; Halloran, J. W.; Cooper, A. R.


    Oxygen self diffusion coefficients were determined in single crystal alpha-Al2O3 using the gas exchange technique. The samples were semi-infinite slabs cut from five different boules with varying background impurities. The diffusion direction was parallel to the c-axis. The tracer profiles were determined by two techniques, single spectrum proton activation and secondary ion mass spectrometry. The SIMS proved to be a more useful tool. The determined diffusion coefficients, which were insensitive to impurity levels and oxygen partial pressure, could be described by D = .00151 exp (-572kJ/RT) sq m/s. The insensitivities are discussed in terms of point defect clustering. Two independent models are consistent with the findings, the first considers the clusters as immobile point defect traps which buffer changes in the defect chemistry. The second considers clusters to be mobile and oxygen diffusion to be intrinsic behavior, the mechanism for oxygen transport involving neutral clusters of Schottky quintuplets.

  2. The control system position to the electric probe in the Tokamak Novillo. Ph.D. Thesis

    Sanchezgarcia, A.M.


    An electric probe is used to determine the parameters of electronic temperatures, the electron density and the plasma potential in Tokamak machines. On this machine the electric probes are used only in the plasma edge due to the intensive flow of high energy particles. This is the region in which the plasma density and temperature are relatively low. This work shows the design and construction of an electro mechanic system which is used to control the position of the probe into the discharge chamber. This system is called `The control system position to the electric probe in the tokamak Novillo`. This controller is a minimum system to rule a step motor by a logic sequence commutation. This is done by sliding the probe in a radial way with millimetric precision into the discharge chamber. To this purpose it is used as step motor, due to its principal characteristic as the control of the end element position without needing a feedback of the error signal. The system function consists of reading, through a board, the data corresponding to the position where it is wanted to place the probe; it also displays by a numeric indicator the position in which the probe is located (in an interval from 0 to 100 mm), and provides the logic sequence commutation for the step motor. The minimum system is consists of the microcontroller 8748-8 that gives precision control of the electric probe position in the Tokamak Novillo, by programming, associated circuits, amplification unit bi-phase unipolar and switching power (they supply the power to the control circuit and to the step motor too), avoiding the destruction of the electric probe.

  3. Observations of hydrogen and helium isotopes in solar cosmic rays. Ph.D. Thesis

    Hurford, G. J.


    The isotopic composition of hydrogen and helium in solar cosmic rays provides a means of studying solar flare particle acceleration mechanisms since the enhanced relative abundance of rare isotopes, such as H-2, H-3, and He-3, is due to their production by inelastic nuclear collisions in the solar atmosphere during the flare. Electron isotope spectrometer on an IMP spacecraft was used to measure this isotopic composition. The response of the dE/dx-E particle telescope is discussed, and alpha particle channeling in thin detectors is identified as an important background source affecting measurement of low values of (He-3/He-4). The flare-averaged results obtained for the period October, 1972 November, 1973 are given.

  4. Adaptive Strategies for Controls of Flexible Arms. Ph.D. Thesis

    Yuan, Bau-San


    An adaptive controller for a modern manipulator has been designed based on asymptotical stability via the Lyapunov criterion with the output error between the system and a reference model used as the actuating control signal. Computer simulations were carried out to test the design. The combination of the adaptive controller and a system vibration and mode shape estimator show that the flexible arm should move along a pre-defined trajectory with high-speed motion and fast vibration setting time. An existing computer-controlled prototype two link manipulator, RALF (Robotic Arm, Large Flexible), with a parallel mechanism driven by hydraulic actuators was used to verify the mathematical analysis. The experimental results illustrate that assumed modes found from finite element techniques can be used to derive the equations of motion with acceptable accuracy. The robust adaptive (modal) control is implemented to compensate for unmodelled modes and nonlinearities and is compared with the joint feedback control in additional experiments. Preliminary results show promise for the experimental control algorithm.

  5. Oxides of Nitrogen Emissions from the Combustion of Monodisperse Liquid Fuel Sprays. Ph.D. Thesis

    Sarv, H.


    A study of NO sub x formation in a one dimensional monodisperse spray combustion system, which allowed independent droplet size variation, was conducted. Temperature, NO and NO sub x concentrations were measured in the transition region, encompassing a 26 to 74 micron droplet size range. Emission measurements of hydrocarbons, carbon monoxide, carbon dioxide and oxygen were also made. The equivalence ratio was varied between 0.8 and 1.2 for the fuels used, including methanol, isopropanaol, n-heptane and n-octane. Pyridine and pyrrole were added to n-heptane as nitrogen-containing additives in order to simulate synthetic fuels. Results obtained from the postflame regions using the pure fuels indicate an optimum droplet size in the range of 43 to 58 microns for minimizing NO sub x production. For the fuels examined, the maximum NO sub x reductions relative to the small droplet size limit were about 10 to 20% for lean and 20 to 30% for stoichiometric and rich mixtures. This behavior is attributed to droplet interactions and the transition from diffusive to premixed type of burning. Preflame vaporization controls the gas phase stoichiometry which has a significant effect on the volume of the hot gases surrounding a fuel droplet, where NO sub x is formed.

  6. Entrance and exit region friction factor models for annular seal analysis. Ph.D. Thesis

    Elrod, David Alan


    The Mach number definition and boundary conditions in Nelson's nominally-centered, annular gas seal analysis are revised. A method is described for determining the wall shear stress characteristics of an annular gas seal experimentally. Two friction factor models are developed for annular seal analysis; one model is based on flat-plate flow theory; the other uses empirical entrance and exit region friction factors. The friction factor predictions of the models are compared to experimental results. Each friction model is used in an annular gas seal analysis. The seal characteristics predicted by the two seal analyses are compared to experimental results and to the predictions of Nelson's analysis. The comparisons are for smooth-rotor seals with smooth and honeycomb stators. The comparisons show that the analysis which uses empirical entrance and exit region shear stress models predicts the static and stability characteristics of annular gas seals better than the other analyses. The analyses predict direct stiffness poorly.

  7. The Policy Formation Process: A Conceptual Framework for Analysis. Ph.D. Thesis

    Fuchs, E. F.


    A conceptual framework for analysis which is intended to assist both the policy analyst and the policy researcher in their empirical investigations into policy phenomena is developed. It is meant to facilitate understanding of the policy formation process by focusing attention on the basic forces shaping the main features of policy formation as a dynamic social-political-organizational process. The primary contribution of the framework lies in its capability to suggest useful ways of looking at policy formation reality. It provides the analyst and the researcher with a group of indicators which suggest where to look and what to look for when attempting to analyze and understand the mix of forces which energize, maintain, and direct the operation of strategic level policy systems. The framework also highlights interconnections, linkage, and relational patterns between and among important variables. The framework offers an integrated set of conceptual tools which facilitate understanding of and research on the complex and dynamic set of variables which interact in any major strategic level policy formation process.

  8. York University PhD Thesis about the voyage of the Walnut


    York'i Ülikooli sotsiaalantropoloogia üliõpilase Lynda Männiku uurimistööst, mis käsitleb 1948. a. novembris ohtliku merereisi Briti miinilaeval "Walnut" Rootsist Kanadasse üle elanud inimeste, kelle hulgas oli ka Lynda isa, saatust

  9. Effects of road traffic background noise on judgments of individual airplane noises. Ph.D. Thesis

    Powell, C. A.


    Two laboratory experiments were conducted to investigate the effects of road-traffic background noise on judgments of individual airplane flyover noises. In the first experiment, 27 subjects judged a set of 16 airplane flyover noises in the presence of traffic-noise sessions of 30-min duration consisting of the combinations of 3 traffic-noise types and 3 noise levels. In the second experiment, 24 subjects judged the same airplane flyover noises in the presence of traffic-noise sessions of 10-min duration consisting of the combinations of 2 traffic-noise types and 4 noise levels. In both experiments the airplane noises were judged less annoying in the presence of high traffic-noise levels than in the presence of low traffic-noise levels.

  10. Effect of wave localization on plasma instabilities. Ph.D. Thesis

    Levedahl, William Kirk


    The Anderson model of wave localization in random media is involved to study the effect of solar wind density turbulence on plasma processes associated with the solar type III radio burst. ISEE-3 satellite data indicate that a possible model for the type III process is the parametric decay of Langmuir waves excited by solar flare electron streams into daughter electromagnetic and ion acoustic waves. The threshold for this instability, however, is much higher than observed Langmuir wave levels because of rapid wave convection of the transverse electromagnetic daughter wave in the case where the solar wind is assumed homogeneous. Langmuir and transverse waves near critical density satisfy the Ioffe-Reigel criteria for wave localization in the solar wind with observed density fluctuations -1 percent. Numerical simulations of wave propagation in random media confirm the localization length predictions of Escande and Souillard for stationary density fluctations. For mobile density fluctuations localized wave packets spread at the propagation velocity of the density fluctuations rather than the group velocity of the waves. Computer simulations using a linearized hybrid code show that an electron beam will excite localized Langmuir waves in a plasma with density turbulence. An action principle approach is used to develop a theory of non-linear wave processes when waves are localized. A theory of resonant particles diffusion by localized waves is developed to explain the saturation of the beam-plasma instability. It is argued that localization of electromagnetic waves will allow the instability threshold to be exceeded for the parametric decay discussed above.

  11. Rime ice accretion and its effect on airfoil performance. Ph.D. Thesis. Final Report

    Bragg, M. B.


    A methodology was developed to predict the growth of rime ice, and the resulting aerodynamic penalty on unprotected, subcritical, airfoil surfaces. The system of equations governing the trajectory of a water droplet in the airfoil flowfield is developed and a numerical solution is obtained to predict the mass flux of super cooled water droplets freezing on impact. A rime ice shape is predicted. The effect of time on the ice growth is modeled by a time-stepping procedure where the flowfield and droplet mass flux are updated periodically through the ice accretion process. Two similarity parameters, the trajectory similarity parameter and accumulation parameter, are found to govern the accretion of rime ice. In addition, an analytical solution is presented for Langmuir's classical modified inertia parameter. The aerodynamic evaluation of the effect of the ice accretion on airfoil performance is determined using an existing airfoil analysis code with empirical corrections. The change in maximum lift coefficient is found from an analysis of the new iced airfoil shape. The drag correction needed due to the severe surface roughness is formulated from existing iced airfoil and rough airfoil data. A small scale wind tunnel test was conducted to determine the change in airfoil performance due to a simulated rime ice shape.

  12. Microscopic aspects of the effect of friction reducers at the lubrication limit. Ph.D. Thesis

    Mansot, J. L.


    An attempt is made to analytically model the physicochemical properties of lubricants and their capacity to reduce friction. A technique of frozen fracturing of the lubricants was employed to study the dispersion of additives throughout a lubricant. Adsorption was observed at the liquid-solid interface, which was the region where the solid and lubricant met, and the molecular dispersion of the additive enhanced the effectiveness of the lubricant. The electrically conductive characteristics of the lubricant at the friction interface indicated the presence of tunneling effects. The Bethe model was used to examine the relationship between the coefficient of friction and the variation of interface thickness. The electron transport permitted an inelastic tunnel electron spectroscopic investigation of the molecular transformations undergone by the additive during friction episodes.

  13. Effects of cooling system parameters on heat transfer in PAFC stack. Ph.D. Thesis

    Abdul-Aziz, Ali A.


    Analytical and experimental study for the effects of cooling system parameters on the heat transfer and temperature distribution in the electrode plates of a phosphoric acid fuel-cell has been conducted. An experimental set-up that simulates the operating conditions prevailing in a phosphoric-acid fuel-cell stack was designed and constructed. The set-up was then used to measure the overall heat transfer coefficient, the thermal contact resistance, and the electrode temperature distribution for two different cooling plate configurations. Two types of cooling plate configurations, serpentine and straight, were tested. Air, water, and oil were used as coolants. Measurements for the heat transfer coefficient and the thermal contact resistance were made for various flow rates ranging from 16 to 88 Kg/hr, and stack clamping pressure ranging from O to 3448 Kpa. The experimental results for the overall heat transfer coefficient were utilized to derive mathematical relations for the overall heat transfer coefficient as a function of stack clamping pressure and Reynolds number for the three coolants. The empirically derived formulas were incorporated in a previously developed computer program to predict electrodes temperature distribution and the performance of the stack cooling system. The results obtained were then compared with those available in the literature. The comparison showed maximum deviation of +/- 11%.

  14. Thermal effects in two-phase flow through face seals. Ph.D. Thesis

    Basu, Prithwish


    When liquid is sealed at high temperature, it flashes inside the seal due to pressure drop and/or viscous heat dissipation. Two-phase seals generally exhibit more erratic behavior than their single phase counterparts. Thermal effects, which are often neglected in single phase seal analyses, play an important role in determining seal behavior under two-phase operation. It is necessary to consider the heat generation due to viscous shear, conduction into the seal rings and convection with the leakage flow. Analytical models developed work reasonably well at the two extremes - for low leakage rates when convection is neglected and for higher leakage rates when conduction is neglected. A preliminary model, known as the Film Coefficient Model, is presented which considers conduction and convection both, and allows continuous boiling over an extended region unlike the previous low-leakage rate model which neglects convection and always forces a discrete boiling interface. Another simplified, semi-analytical model, based on the assumption of isothermal conditions along the seal interafce, has been developed for low leakage rates. The Film Coefficient Model may be used for more accurate and realistic description.

  15. A methodology for the synthesis of robust feedback systems. Ph.D. Thesis

    Milich, David Albert


    A new methodology is developed for the synthesis of linear, time-variant (LTI) controllers for multivariable LTI systems. The resulting closed-loop system is nominally stable and exhibits a known level of performance. In addition, robustness of the feedback system is guaranteed, i.e., stability and performance are retained in the presence of multiple unstructured uncertainty blocks located at various points in the feedback loop. The design technique is referred to as the Causality Recovery Methodology (CRM). The CRM relies on the Youla parameterization of all stabilizing compensators to ensure nominal stability of the feedback system. A frequency-domain inequality in terms of the structured singular value mu defines the robustness specification. The optimal compensator, with respect to the mu condition, is shown to be noncausal in general. The aim of the CRM is to find a stable, causal transfer function matrix that approximates the robustness characteristics of the optimal solution. The CRM, via a series of infinite-dimensional convex programs, produces a closed-loop system whose performance robustness is at least as good as that of any initial design. The algorithm is approximated by a finite dimensional process for the purposes of implementation. Two numerical examples confirm the potential viability of the CRM concept; however, the robustness improvement comes at the expense of increased computational burden and compensator complexity.

  16. Space Satellite Dynamics with Applications to Sunlight Pressure Attitude Control. Ph.D. Thesis

    Stuck, B. W.


    A research program into three aspects of space satellite dynamics was carried out. First, a four-dimensional space-time formulation of Newtonian mechanics is developed. This theory allows a new physical interpretation of the conservation theorems of mechanics first derived rigorously by Noether. Second, a new concept for estimating the three angles which specify the orientation in space of a rigid body is presented. Two separate methods for implementing this concept are discussed, one based on direction cosines, the other on quaternions. Two examples are discussed: constant orientation in space, and constant rate of change of the three angles with time. Third, two synchronous equatorial orbit communication satellite designs which use sunlight pressure to control their attitude are analyzed. Each design is equipped with large reflecting surfaces, called solar sails, which can be canted in different directions to generate torques to correct pointing errors.

  17. Experimental study of unsteady hydrodynamic force matrices on whirling centrifugal pump impellers. Ph.D. Thesis

    Belgacem, Jery


    An experimental facility was constructed and instrumented. A set of centrifugal flow pumps whose impellers were made to follow a controlled circular whirl motion were studied. The aim was to characterize the steady and unsteady fluid forces measured on the impeller under various pump operating conditions. The postulation was that the unsteady lateral forces result from interactions between the impeller and the surrounding diffuser and/or volute (via the working fluid), and that under certain flow regimes these forces can drive unstable lateral motions of the pump rotor. The lateral hydrodynamic forces were decomposed into their steady and unsteady parts, the latter being further expressed in terms of a generalized fluid stiffness matrix. Conclusions regarding the effect of impeller geometry could not be reached given the similarity of the tested designs. However, other results on phenomena such as skin friction and leakage flow are presented. Some of the findings are compared to experimental and theoretical data from other sources. Finally, the rotordynamic consequences of the results are discussed as the present data were applied to the case of the Space Shuttle Main Engine (SSME) High Pressure Oxidizer Turbopump (HPOTP).

  18. Teleseismic array analysis of upper mantle compressional velocity structure. Ph.D. Thesis

    Walck, M. C.


    Relative array analysis of upper mantle lateral velocity variations in southern California, analysis techniques for dense data profiles, the P-wave upper mantle structure beneath an active spreading center: the Gulf of California, and the upper mantle under the Cascade ranges: a comparison with the Gulf of California are presented.

  19. International Ultraviolet Explorer Observations of Wolf-Rayet Binaries: Wind Structures. Ph.D. Thesis

    Koenigsberger, G.


    Spectra of six WN + OB Wolf-Rayet systems obtained with the IUE are analyzed for phase-dependent variations. Periodic variability at emission-line frequencies is detected in V444 Cyg, HD 90657, HD 211853, HD 186943 and HD 94546 on low dispersion SWP images. No changes in the low dispersion spectra of HD 193077 are apparent. We find the variations in the UV to be similar in nature to those observed in optical spectra of various WR sources. That is, there is a strengthening of absorption components in P Cygni-type features at orbital phases in which the O-star is behind the WR wind. With the aid of a computer code which models this type of variations, and through a comparison with HD 193077, the dominant mechanism producing the variations is shown to be selective atmospheric eclipses of the O-star by the WR wind. Based on this interpretation, a straightforward technique is applied to the line of N IV 1718, by which an optical depth distribution in the WN winds of the form tau varies as r(-1) is derived for 16 r 66 solar radii. Phase-dependent variations in the width of the C IV 1550 absorption component in V444 Cyg, HD 90657 and HD 211853 are interpretated as wind-wind collision effects.

  20. Structure and evolution of the large scale solar and heliospheric magnetic fields. Ph.D. Thesis

    Hoeksema, J. T.


    Structure and evolution of large scale photospheric and coronal magnetic fields in the interval 1976-1983 were studied using observations from the Stanford Solar Observatory and a potential field model. The solar wind in the heliosphere is organized into large regions in which the magnetic field has a componenet either toward or away from the sun. The model predicts the location of the current sheet separating these regions. Near solar minimum, in 1976, the current sheet lay within a few degrees of the solar equator having two extensions north and south of the equator. Soon after minimum the latitudinal extent began to increase. The sheet reached to at least 50 deg from 1978 through 1983. The complex structure near maximum occasionally included multiple current sheets. Large scale structures persist for up to two years during the entire interval. To minimize errors in determining the structure of the heliospheric field particular attention was paid to decreasing the distorting effects of rapid field evolution, finding the optimum source surface radius, determining the correction to the sun's polar field, and handling missing data. The predicted structure agrees with direct interplanetary field measurements taken near the ecliptic and with coronameter and interplanetary scintillation measurements which infer the three dimensional interplanetary magnetic structure. During most of the solar cycle the heliospheric field cannot be adequately described as a dipole.

  1. UTD analysis of electromagnetic scattering by flat structures. Ph.D. Thesis

    Sikta, F. A.; Peters, L., Jr.


    The different scattering mechanisms that contribute to the radar cross of finite flat plates were identified and analyzed. The geometrical theory of diffraction, the equivalent current and the corner diffraction are used for this study. A study of the cross polarized field for a monopole mounted on a plate is presented, using novel edge wave mechanism in the analysis. The results are compared with moment method solutions as well as measured data.

  2. A search for periodic structure in solar 2 cm microwave radiation. Ph.D. Thesis

    Sentman, D. D.


    A power spectral analysis of 285 hr of 2 cm microwave intensity data showed no statistically significant ( 96% confidence) periodicities in the frequency range 1 to 15 mHz. No correlation was found between 2 cm periodicities and solar activity in H alpha, X-ray, and several microwave frequencies. A small shift of power toward higher frequencies in the power spectrum of the 2 cm data was found to be correlated with solar H alpha and X-ray activity. Using the statistical properties of power spectra, an expression for the ratio of the minimum detectable peak-to-peak to ambient temperature at chromospheric heights may be derived. Applied to a model for oscillation bursts in quiescent supergranules, and using the most significant results of experiments to detect the microwave periodicities, this expression yields an upper limit of approximately .0015.

  3. Lunar Seismology: the Internal Structure of the Moon. Ph.D. Thesis

    Goins, N. R.


    The direct P and S wave arrival times are the primary data set that can be measured on the seismograms of natural lunar seismic events. Polarization filtering techniques allow the enhancement of secondary body wave arrivals and record curves to identify the secondary phases and deduce structural information. Finally, shear wave amplitude vs. distance curves yield information on the location and magnitude of seismic velocity gradients in the interior. The results of these analyses show that the moon appears to have a two-layer crust at all four seismic stations: a 20 km upper crust that seems to be constant at all sites and a lower crust that is 40 km thick at stations 12 and 14 (mare), 55 + or - 10 km at station 16 (highland), and tentatively either 40 km or 70 km at station 15. The lower mantle extends from 480 km to at least 1100 km depth which is the maximum depth of penetration of all but a few seismic waves used as data. No definitive evidence for or against a lunar core exists.

  4. Real time identification of large space structures. Ph.D. Thesis - MIT

    Voss, Janice E.


    Identification of frequencies, damping ratios, and mode shapes of large space structures (LSSs) are examined in real time. Real time processing allows for quick updates of model processing after a reconfiguration of structural failure. Recursive lattice least squares (RLLS) was selected as the baseline algorithm for the identification. Simulation results on a one dimensional LSS demonstrated that it provides good estimates, was not ill-conditioned in the presence of under-excited modes, allowed activity by a supervisory control system which prevented damage to the LSS or excessive drift, and was capable of real-time processing for typical LSS models. A suboptimal version of RLLS, which is equivalent to simulated parallel processing, was derived. A NASTRAN model of the dual keel U.S. space station was used to demonstrate the input/identification algorithm package in a more realistic simulation. Because the first eight flexible modes were very close together, the identification was much more difficult than in the simple examples. Even so, the model was accurately identified in real time.

  5. Robust fault diagnosis of physical systems in operation. Ph.D. Thesis - Rutgers - The State Univ.

    Abbott, Kathy Hamilton


    Ideas are presented and demonstrated for improved robustness in diagnostic problem solving of complex physical systems in operation, or operative diagnosis. The first idea is that graceful degradation can be viewed as reasoning at higher levels of abstraction whenever the more detailed levels proved to be incomplete or inadequate. A form of abstraction is defined that applies this view to the problem of diagnosis. In this form of abstraction, named status abstraction, two levels are defined. The lower level of abstraction corresponds to the level of detail at which most current knowledge-based diagnosis systems reason. At the higher level, a graph representation is presented that describes the real-world physical system. An incremental, constructive approach to manipulating this graph representation is demonstrated that supports certain characteristics of operative diagnosis. The suitability of this constructive approach is shown for diagnosing fault propagation behavior over time, and for sometimes diagnosing systems with feedback. A way is shown to represent different semantics in the same type of graph representation to characterize different types of fault propagation behavior. An approach is demonstrated that threats these different behaviors as different fault classes, and the approach moves to other classes when previous classes fail to generate suitable hypotheses. These ideas are implemented in a computer program named Draphys (Diagnostic Reasoning About Physical Systems) and demonstrated for the domain of inflight aircraft subsystems, specifically a propulsion system (containing two turbofan systems and a fuel system) and hydraulic subsystem.

  6. Brenda K. Edwards, PhD

    Brenda K. Edwards, PhD, has been with the Surveillance Research Program (SRP) and its predecessor organizations at the National Cancer Institute (NCI) since 1989, serving as SRP’s Associate Director from 1990-2011.

  7. Biomedical PhD education - an international perspective

    Mulvany, Michael J.


    The PhD, otherwise known as the doctor of philosophy or Dr. Phil., is an internationally recognized degree, indicating that the PhD graduate has received training in research under supervision. Traditionally, the PhD was the route to an academic career, with most successful PhD graduates receivin...

  8. Protein engineering with PHD zinc fingers

    Full text: The plant homeodomain (PHD) is a protein domain of ∼45-100 residues that is characterised by a Cys4-His-Cys3 zinc-binding motif These domains are found widely in nuclear proteins involved in transcription and seem to have an array of functions. In some instances, PHD domains have been shown to be important in mediating protein-protein interactions. Sequence alignments indicate that while the cysteines, histidine and a few other key residues are strictly conserved, the rest of the domain can vary greatly in terms of both amino acid composition and length. Given the diversity of functions they fulfill in nature, we propose to use these PHD domains as prototype protein interaction scaffolds for drug design. We have determined the solution structure of the second PHD domain of Mi2 (Mi2-PHD2) by multi-dimensional NMR spectroscopy. The structure shows that Mi2-PHD2 adopts a globular fold in solution and contains a di-metal-binding structural motif with the two zinc ions ligated in an interleaved manner. While this structure is similar to that of other PHD domains, two flexible loop regions can also be observed. These loops may be suitable target regions for protein engineering studies, where novel binding functions could be introduced. To test the stability of the Mi2-PHD2 fold, we have made a number of mutations and insertions in the two loop regions NMR spectra of these mutants show they adopt native-like conformations. We are currently determining the structures of a selection of these mutants and are using a combination of rational and combinatorial methods to introduce new functions

  9. What PhD students really want

    Mao, Minnie


    The road to becoming an astronomer is exciting, but often fraught with danger and conflicting messages. A PhD student is inundated with catch-phrases such as "publish or perish" and "it's not about the quantity, but the quality of work". How do we know which advice to follow? How can we publish copious amounts of quality work in only three years so as to maximize our success in the future? How do we even know what "good quality" really is? With only a short time to prepare ourselves for the big wide world of Astronomy, what is the best way for a PhD student to maximize their research and ultimately maximize their success as a real astronomer? The PhD students of today are the astronomers of tomorrow, but their journey depends on a positive work environment in which they can thrive and improve. Here I present the results of a survey of current PhD students on how they believe they can maximize their success in science. I find that PhD students in Australia expect to write more papers during their PhD than is e...

  10. Expression and DNA methylation levels of prolyl hydroxylases PHD1, PHD2, PHD3 and asparaginyl hydroxylase FIH in colorectal cancer

    Colorectal cancer (CRC) is one of the most common and comprehensively studied malignancies. Hypoxic conditions during formation of CRC may support the development of more aggressive cancers. Hypoxia inducible factor (HIF), a major player in cancerous tissue adaptation to hypoxia, is negatively regulated by the family of prolyl hydroxylase enzymes (PHD1, PHD2, PHD3) and asparaginyl hydroxylase, called factor inhibiting HIF (FIH). PHD1, PHD2, PHD3 and FIH gene expression was evaluated using quantitative RT-PCR and western blotting in primary colonic adenocarcinoma and adjacent histopathologically unchanged colonic mucosa from patients who underwent radical surgical resection of the colon (n = 90), and the same methods were used for assessment of PHD3 gene expression in HCT116 and DLD-1 CRC cell lines. DNA methylation levels of the CpG island in the promoter regulatory region of PHD1, PHD2, PHD3 and FIH were assessed using bisulfite DNA sequencing and high resolution melting analysis (HRM) for patients and HRM analysis for CRC cell lines. We found significantly lower levels of PHD1, PHD2 and PHD3 transcripts (p = 0.00026; p < 0.00001; p < 0.00001) and proteins (p = 0.004164; p = 0.0071; p < 0.00001) in primary cancerous than in histopathologically unchanged tissues. Despite this, we did not observe statistically significant differences in FIH transcript levels between cancerous and histopathologically unchanged colorectal tissue, but we found a significantly increased level of FIH protein in CRC (p = 0.0169). The reduced PHD3 expression was correlated with significantly increased DNA methylation in the CpG island of the PHD3 promoter regulatory region (p < 0.0001). We did not observe DNA methylation in the CpG island of the PHD1, PHD2 or FIH promoter in cancerous and histopathologically unchanged colorectal tissue. We also showed that 5-Aza-2’-deoxycytidine induced DNA demethylation leading to increased PHD3 transcript and protein level in HCT116 cells. We

  11. Towards a doctoral thesis through published works.

    Breimer, L H; Mikhailidis, D P


    Doctoral theses submitted in medical schools under a system dependent on publications (Sweden) and one which was not (UK) were compared. A subset consisting of UK theses containing papers (about 1/3 of all UK theses) was used. The publication-based theses gave candidates a significantly higher (P < 0.03) profile in terms of key authorship positions. Nevertheless, in 66% of the UK theses with papers the candidate was either the first or sole author. Swedish and UK theses with papers were of equal quality when assessed by the number of papers in journals: a) ranked in the top 100 (14% vs 10%) or 200 (26% vs 32%); or b) used more than once and either ranked in the top 1000 (median 224 vs 218) or in the top two thirds by subject section (98 vs 100%). UK theses benefitted from the greater impact of journals emanating from the UK compared to continental Europe (P < 0.001). An estimated 13% of UK PhD theses overall included three or more papers per thesis despite no requirement of publication. A publication-based doctorate should be introduced on trial in parallel with the existing systems to ensure efficiency and international comparability. PMID:8068863

  12. Arbejdspapir til Thesis-seminar

    Damkjaer, Maja Sonne


    Arbejdspapir til Thesis-seminar afholdt ved Forskningsseminar i Forskningsprogrammet: Medier, Kommunikation og Samfund, Institut for Æstetik og Kommunikation, Aarhus Universitet. Afhandlingens teoretiske afsnit.......Arbejdspapir til Thesis-seminar afholdt ved Forskningsseminar i Forskningsprogrammet: Medier, Kommunikation og Samfund, Institut for Æstetik og Kommunikation, Aarhus Universitet. Afhandlingens teoretiske afsnit....

  13. District Heating in Areas with Low Energy Houses

    Tol, Hakan Ibrahim

    renewable energy sources and the heat energy requirements, both in terms of the variations involved, such through the excessive production of heat by means of solar based systems, heat that cannot be used immediately but can be stored in borehole storage systems, to be used then in the cold winter period......This PhD thesis presents a summary of a three-year PhD project involving three case studies, each pertaining to a typical regional Danish energy planning scheme with regard to the extensive use of low-energy district heating systems, operating at temperatures as low as 55°C for supply and 25°C...... for return, and with the aim of intensive exploitation of renewable energy sources. The hypothesis is that a detailed analysis of energy performance and cost of construction and operation of low energy district heating systems can be used as a rational basis for planning use of district heating in areas...

  14. Interview with Di Gao PhD

    Di Gao


    Full Text Available Di Gao is currently a scientist in the Quality Control department of AstraZeneca. She is responsible for technology transfer, stability programs and supporting regulatory submission. She has a BSc and PhD degree in chemistry and interned with Genentech in 2012. After completing her Ph.D. from University of Michigan in June 2013, she joined the R&D department of the United States Pharmacopeia (USP to support USP monograph modernization and since June 2014 she has been working in her current position at AstraZeneca. Recently, she won a prestigious award from Women in Bio (WIB. WIB is an organization of professionals committed to promoting careers, leadership and entrepreneurship for women in the life sciences. This interview was conducted by Roland J.W. Meesters PhD, Editor-in-Chief of Journal of Applied Bioanalysis.

  15. Three new students selected for the ATLAS PhD Grant Scheme

    Antonella Del Rosso


    Initiated in 2013, the ATLAS PhD Grant Scheme aims to enable young, talented and motivated students to work on part of their PhD thesis at CERN. The collaboration has just selected the three students who will start their theses in 2016.   The three students who received the ATLAS grant, which will cover part of their PhD studies. From left to right: Ruth Jacobs (Germany), Artem Basalaev (Russia), Nedaa B I Asbah (Palestine). The ATLAS PhD Grant Scheme was made possible thanks to a large donation by former ATLAS spokespersons Fabiola Gianotti and Peter Jenni, who started the fund with money from the Fundamental Physics Prize they received in 2013. Applications are handled by CERN HR, via this link. The aim of the initiative is to offer a unique educational opportunity to students within the ATLAS collaboration and to give them the possibility to continue their career in particle physics. Selected candidates receive a stipend allowing them to spend one year at CERN, followed by one year at their h...

  16. Aquaponics : Practical thesis in Australia

    Kopsa, Piia


    This thesis is about building an aquaponics system to an Australian farm. This thesis begins by introducing what aquaponics is, and continues by designing and building an aquaponics system to a farm in Australia. One of the goals is to learn more about aquaponics that’s a growing idea all around the world and raise the farm’s self-sustainability level. Information for the thesis has been gathered from several books, internet sources, followed by visits and inter-views from users of existing a...

  17. Interview with Di Gao PhD

    Di Gao


    Di Gao is currently a scientist in the Quality Control department of AstraZeneca. She is responsible for technology transfer, stability programs and supporting regulatory submission. She has a BSc and PhD degree in chemistry and interned with Genentech in 2012. After completing her Ph.D. from University of Michigan in June 2013, she joined the R&D department of the United States Pharmacopeia (USP) to support USP monograph modernization and since June 2014 she has been working in her current p...

  18. Gaussian Mixture PHD Filtering with Variable Probability of Detection

    Hendeby, Gustaf; Karlsson, Rickard


    The probabilistic hypothesis density (PHD) filter has grown in popularity during the last decade as a way to address the multi-target tracking problem. Several algorithms exist; for instance under linear-Gaussian assumptions, the Gaussian mixture PHD (GM-PHD) filter. This paper extends the GM-PHD filter to the common case with variable probability of detection throughout the tracking volume. This allows for more efficient utilization, e.g., in situations with distance dependent probability of...

  19. Thesis-Building: Architecture, Alchemy and the Constructive Moment(s of a Doctoral Dissertation

    Willem de Bruijn


    Full Text Available This paper looks back at the long and sometimes difficult process of doing a ‘PhD’. It asks how certain ‘moments’ in the building of a doctoral thesis – moments of conception, of discovery, of despair, of truth, of revelation and of jouissance – inform the building of a thesis. By revisiting these moments, the paper traces the genesis of the author’s thesis on Architecture and Alchemy and explores the metaphor of construction encountered in the work of cultural theorist Walter Benjamin.Drawing on some of the historical sources of the thesis, in particular the emblem books of seventeenth-century alchemist Michael Maier (1568-1622, the paper argues that the above-named ‘moments’ in a PhD constitute an ensemble of impassioned investment, which can be known as the PhD-pathos. This paper, then, can be read as no more, or less, than a pathological guide to the PhD, where architecture and alchemy come into play as polar opposites in the process of construction and change that thesis-building is.

  20. Thesis on safeguards gains doctorate

    Full text: One of the most complete analyses yet to be made outside the Agency of its Safeguards system for preventing diversion of materials to military purposes has gained for its author a Doctorate of Philosophy. The subject was chosen as a thesis by Miss Gabrielle Martino, daughter of His Excellency Mr. Enrico Martino, Italian Ambassador to Austria and Resident Representative to IAEA. Miss Martino has been studying in the Faculty of Political Science at Rome University. Her thesis, which runs to 110 pages, traces the history of safeguards and the stages in evolution to the system adopted by the General Conference at its 1965 Session held in Tokyo. (author)

  1. PhD students share their work

    Joannah Caborn Wengler


    Last week, the second Doctoral Student Assembly gave students in the final stages of their PhD at CERN the chance to meet and present their work.   On 9 May, 24 students who are completing their PhD under the CERN Doctoral Student Programme were joined by their CERN supervisors and some of their university supervisors at an event organised by HR and the Technical Students Committee (TSC). After an address by the Director-General Rolf Heuer and short presentations by Ingrid Haug from HR and TSC Chair Stephan Russenschuck, the students presented their work in a poster session. Held in a packed Council Chamber, the event was a great opportunity for the doctoral students to get to know each other and to share their work in fields as diverse as radiation protection, computing, physics and engineering.

  2. ATLAS PhD Grant Scholarship Programme

    Abha Eli Phoboo


    On 11 February, the first recipients of the ATLAS PhD Grant were presented with a certificate by the programme’s selection committee. The three scholars - Lailin Xu of China, Josefina Alconada of Argentina and Gagik Vardanyan of Armenia - were delighted at being able to continue their PhD programmes at CERN.   With certificates, from left: Lailin Xu, Josefina Alconada, and Gagik Vardanyan. The selection committee members, from left: IFAE Barcelona’s Martine Bosman, Fabiola Gianotti, Peter Jenni and from CERN HR James Purvis. (Image: ATLAS/Claudia Marcelloni). Former ATLAS spokespersons Peter Jenni and Fabiola Gianotti started the fund with the Fundamental Physics Prize award money they received last year. Both have used the entirety of their prizes for educational and humanitarian programmes. "We wanted to do something for students who are working on ATLAS, in particular those who otherwise could not come here and actually see the detector they are working on,&am...

  3. 2nd My phd International Conference

    Armand Faganel


    The article presents the organization of the second My phd International Conference organized in June in Bratislava. The organizer Friedrich Ebert Foundation is a German non-profit organization. During the conference young researchers from various fields dealt with the issue of ‘New Europe’ and the challenges of sustainable development. The conference was also an opportunity for young researchers to meet new colleagues and exchange their views. The interest was very big since only 40 percent ...

  4. Master's thesis policies in nursing education.

    May, K M; Holzemer, W L


    A telephone survey of 25 schools of nursing with doctoral programs was conducted to inquire about their master's thesis policies. Six programs require a thesis. Sixteen programs provide both thesis and other options, described in the paper. Other policy issues are discussed which include: relation of thesis to faculty research, criteria for serving on a master's thesis committee, and requirements for doctoral admission. Responses to the survey indicate a variety of types and degrees of research experience in master's programs. PMID:2981987

  5. The Reframing of Methodology: Revisiting a PhD Study

    Sarah Dubberley


    The paper draws on a PhD study to explore some methodological dilemmas associated with the execution of qualitative research when framed within positivist study design. The PhD was linked to an externally funded research project which evaluated the implementation of a custody-based intervention in the secure estate. While the PhD was conceived as a qualitative study, informed by interpretivist methodology and associated epistemology, the wider funded study was informed by positivist tradition...

  6. First ‘Gentner Doktor’ finishes PhD at CERN

    Jordan Juras


    In 2007, the CERN Doctoral Student Programme saw the addition of the Gentner Doctoral Student Programme, named in honour of the celebrated nuclear physicist, Wolfgang Gentner. Four years later, on 22 June 2011, Marcel Schuh finished his PhD with a thesis in the field of accelerator technology and became the very first ‘Gentner Doktor’.   Marcel Schuh, first 'Gentner Doktor', celebrates completing his PhD. (Photo by Carsten P. Welsch) Marcel Schuh became a Gentner student in April 2008, after completing a physics degree in 2007 at the University of Heidelberg. His thesis allowed him to gain exposure to CERN and the LHC, as he worked on monitoring and control systems for trigger and readout electronics on the ALICE detector at the LHC. With the support of university supervisor, Carsten P. Welsch, Schuh applied for a Gentner Doctoral Studentship on the Superconducting Proton Linac (SPL) project. “My task was to evaluate whether dedicated higher order mode (HOM) coupler...

  7. Understanding Non-Traditional PhD Students Habitus--Implications for PhD Programmes

    Naidoo, Devika


    Against the background of vast changes in doctoral education and the emergence of non-traditional doctoral programmes, this paper investigates the habitus of non-traditional PhD students at a South African university. Bourdieu's conceptual tool of habitus informed the study. In-depth and open-ended interviews were conducted with 10 non-traditional…

  8. Adidas Group : equity valuation thesis

    Menezes, João Francisco Carvalho Gomes


    This dissertation has the purpose of valuating Adidas Group, a German company, listed on the DAX30, which has three main brands, Adidas, Reebok and TaylorMade. To reach a value for the share of the company, taking in consideration the future of the group, it has been used different methods. The Discounted Cash Flow (DCF), considered by many analysts the most accurate method is the process of valuating Adidas explained more detailed in this Thesis, which allowed us to get to a v...

  9. Lessons from a doctoral thesis.

    Peiris, A N; Mueller, R A; Sheridan, D P


    The production of a doctoral thesis is a time-consuming affair that until recently was done in conjunction with professional publishing services. Advances in computer technology have made many sophisticated desktop publishing techniques available to the microcomputer user. We describe the computer method used, the problems encountered, and the solutions improvised in the production of a doctoral thesis by computer. The Apple Macintosh was selected for its ease of use and intrinsic graphics capabilities. A scanner was used to incorporate text from published papers into a word processing program. The body of the text was updated and supplemented with new sections. Scanned graphics from the published papers were less suitable for publication, and the original data were replotted and modified with a graphics-drawing program. Graphics were imported and incorporated in the text. Final hard copy was produced by a laser printer and bound with both conventional and rapid new binding techniques. Microcomputer-based desktop processing methods provide a rapid and cost-effective means of communicating the written word. We anticipate that this evolving technology will have increased use by physicians in both the private and academic sectors. PMID:2308505

  10. Agro-based Industry of Tharparkar and Barrage Area of Sindh: Concluding Remarks

    Gobind M. Herani


    This study is concluding the thesis about agro-based industry of Tharparkar and barrage area of Sindh, and ninth chapter of the Ph.D submitted in 2002. Demographic, social and economic conditions are compared and results of hypotheses are given theoretically with reference of primary and secondary data in detail. Purpose of the study was to give the complete picture of results of hypotheses and valuable findings. On the completion of this study it has been observed that both the given hypoth...

  11. Agro-based industry of Tharparkar and barrage area of Sindh: Conclusion remarks

    Gobind M. Herani


    This study is concluding the thesis about agro-based industry of Tharparkar and barrage area of Sindh, and ninth chapter of the Ph.D submitted in 2002. Demographic, social and economic conditions are compared and results of hypotheses are given theoretically with reference of primary and secondary data in detail. Purpose of the study was to give the complete picture of results of hypotheses and valuable findings. On the completion of this study it has been observed that both the given hypoth...

  12. "Unexplainable" medical histories and childhood sexual abuse. New doctoral thesis tells you how to investigate the links.

    Getz, L


    This is a brief summary and a personal reflection on Anne Luise Kirkengen's PhD thesis "Embodiment of sexual boundary violations in childhood". It is written to encourage other clinicians to familiarise themselves with this original and important study. It has high relevance for every clinician who is ever confronted with patients that present medical histories that are "diffuse" or unexplainable according to traditional medical knowledge. PMID:10439487

  13. Predicting Computer Science Ph.D. Completion: A Case Study

    Cox, G. W.; Hughes, W. E., Jr.; Etzkorn, L. H.; Weisskopf, M. E.


    This paper presents the results of an analysis of indicators that can be used to predict whether a student will succeed in a Computer Science Ph.D. program. The analysis was conducted by studying the records of 75 students who have been in the Computer Science Ph.D. program of the University of Alabama in Huntsville. Seventy-seven variables were…

  14. Research Collaboration and Commercialization: The PhD Candidate Perspective

    Dooley, Lawrence; Kenny, Breda


    This paper explores PhD students' perceptions of their entrepreneurial and commercial capabilities, their attitude towards university supports and the extent to which they engage in external collaboration. The study concentrated on current PhD researchers at one university in Ireland as a unit of analysis and provides encouraging evidence from the…

  15. An Experiment in Thesis: A Universal Approach

    Noteboom, Jay


    This experimental lesson gives students practice at writing a one sentence thesis statement. Each student chooses a song or short poem for which he must provide a thesis statement. The exercise not only teaches development of the thesis statement, but also stimulates student interest and discussion. Examples are presented. (AH)

  16. The training, careers, and work of Ph.D. physical scientists: Not simply academic

    Smith, Steven J.; Pedersen-Gallegos, Liane; Riegle-Crumb, Catherine


    We present an in-depth portrait of the training, careers, and work of recent Ph.D. physical scientists. Use of specialized training varies widely, with about half often using knowledge of their Ph.D. specialty area in their jobs. The use of specialized training does not, however, correlate with job satisfaction. In this and other important measures, there are relatively few differences between "academics" and "nonacademics." Important job skills for all employment sectors include writing, oral presentation, management, data analysis, designing projects, critical thinking, and working in an interdisciplinary context. Rankings given by respondents of graduate training in some of these skill areas were significantly lower than the importance of these skills in the workplace. We also found that the rated quality of graduate training varies relatively little by department or advisor. Finally, although nonacademic aspirations among graduate students are fairly common, these do not appear to be well supported while in graduate school.

  17. 2. mednarodna konferenca My PhD = 2nd My phd International Conference

    Armand Faganel


    The article presents the organization of the second My phd InternationalConference organized in June in Bratislava. The organizer Friedrich Ebert Foundation is a German non-profit organization. During the conference young researchers from various fields dealt with the issue of ‘New Europe’ and the challenges of sustainable development. The conference was also an opportunity for young researchers to meet new colleagues and exchange their views. The interest was very big since only 40 percent o...

  18. Launching a Geoscience Career: Insights Gained from MS PHD'S Beyond the PhD

    Guzman, W. I.; Johnson, A.; Williamson Whitney, V.; Jansma, P. E.; Huggans, M. J.; Ricciardi, L.


    The Beyond the PhD (B-PhD) Professional Development Program is the newest addition to the Minorities Striving and Pursuing Higher Degrees of Success (MS PHD'S®) Professional Development Program in Earth System Science. This exciting new program is designed to facilitate the development of a new community of underrepresented minority (URM) doctoral candidates and recent doctorate degree recipients in Earth system science (ESS)-related fields. Building upon MS PHD'S extensive professional development activities provided to URM undergraduate and graduate students, B-PhD's vision is to encourage and support URM doctoral students and early career PhD's in becoming part of the global workforce. (Since its inception in 2003, MSPHD'S supports 213 participants of which 42 have achieved the doctoral degree and another 71 are enrolled in doctoral programs.) By providing customized support and advocacy for participants, B-PhD facilitates smoother and informed transitions from graduate school to postdoctoral and tenure-track positions, as well as other "first" jobs in academia, government, industry, and non-profit organizations. In 2011, the first conference for 18 doctoral candidate and recent graduates was hosted at the University of Texas at Arlington's (UTA) College of Science. Using a format of guest speakers, brown bag discussions, and interactive breakout sessions, participants engaged in sessions entitled "Toolkits for Success in Academia, Business and Industry, Federal Government and Non-Profits", "Defining Short, Mid and Long Term Career Goals", "Accessing and Refining Skill Sets and Other Door Openers", "International Preparation and Opportunities", "Paying it Forward/Lifting as You Climb", and "Customized Strategies for Next Steps". This presentation will discuss outcomes from this pilot project, the use of social media to track and support ongoing B-PhD activities, and objectives for future B-PhD workshops.

  19. Pure Mafia - a novel about child labour, plus thesis and commentary

    Ahmad, Rohail


    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. This PhD in Creative Writing consists of three parts. The first part is a full-length novel, approximately 80K words, entitled Pure Mafia. It is a drama about child labour and the Pakistani “carpet mafia”. This is intertwined with the story of an unhappily married man undergoing a midlife crisis who has an affair with a younger woman; the latter is instrumental to the main plot about...

  20. Evaluating the effectiveness of protected areas for maintaining biodiversity, securing habitats, and reducing threats

    Geldmann, Jonas

    Protected areas are amongst the most important conservation responses to halt the loss of biodiversity and cover more than 12.7% of the terrestrial surface of earth. Likewise, protected areas are an important political instrument and a key component of the Convention for Biological Diversity (CBD......); seeking to protect at least 17% of the terrestrial surface and 10% of the coastal and marine areas by 2020. Protected areas are expected to deliver on many different objectives covering biodiversity, climate change mitigation, local livelihood, and cultural & esthetic values. Within each of these...... categories a suite of relevant success matrices exist including; coverage, quality, and performance. This PhD thesis deals with the effectiveness of terrestrial protected areas using temporal data to explore whether protected areas have had a positive effect as a consequence of their establishment. The aim...


    FLÉGL, Martin


    Full Text Available In an attempt to improve the quality of doctoral studies and the satisfaction of PhD students at the Czech University of Life Sciences Prague (CULS Prague the authors disseminated online questionnaire among all PhD students in May and June 2014. The questionnaire covered areas related to doctoral study, PhD supervisors, doctoral scholarship, research publications, and last but not least, to satisfaction with the doctoral study. In this article responses related to research, such as allocation of time to doctoral studies, allocation of time to research, involvement in research projects and satisfaction with research outputs. The authors provide comparison of all above mentioned domains according to faculties as well as form of doctoral studies at CULS Prague.

  2. Time-domain finite elements in optimal control with application to launch-vehicle guidance. PhD. Thesis

    Bless, Robert R.


    A time-domain finite element method is developed for optimal control problems. The theory derived is general enough to handle a large class of problems including optimal control problems that are continuous in the states and controls, problems with discontinuities in the states and/or system equations, problems with control inequality constraints, problems with state inequality constraints, or problems involving any combination of the above. The theory is developed in such a way that no numerical quadrature is necessary regardless of the degree of nonlinearity in the equations. Also, the same shape functions may be employed for every problem because all strong boundary conditions are transformed into natural or weak boundary conditions. In addition, the resulting nonlinear algebraic equations are very sparse. Use of sparse matrix solvers allows for the rapid and accurate solution of very difficult optimization problems. The formulation is applied to launch-vehicle trajectory optimization problems, and results show that real-time optimal guidance is realizable with this method. Finally, a general problem solving environment is created for solving a large class of optimal control problems. The algorithm uses both FORTRAN and a symbolic computation program to solve problems with a minimum of user interaction. The use of symbolic computation eliminates the need for user-written subroutines which greatly reduces the setup time for solving problems.

  3. Enabling Active Ontology Change Management within Semantic Web-based Applications. Mini-thesis: PhD upgrade report

    Liang, Yaozhong; Alani, Harith; Shadbolt, Nigel


    Enabling traceable ontology changes is becoming a critical issue for ontology-based applications. Updating an ontology that is in use may result in inconsistencies between the ontology and the knowledge base, dependent ontologies and applications/services. Current research concentrates on the creation of ontologies and how to manage ontology changes in terms of mapping ontology versions and keeping consistent with the instances. Very little work investigated on-the-fly keeping track of ontolo...

  4. Spherical Earth analysis and modeling of lithospheric gravity and magnetic anomalies. Ph.D. Thesis - Purdue Univ.

    Vonfrese, R. R. B.; Hinze, W. J.; Braile, L. W.


    A comprehensive approach to the lithospheric analysis of potential field anomalies in the spherical domain is provided. It has widespread application in the analysis and design of satellite gravity and magnetic surveys for geological investigation.

  5. Transient response to three-phase faults on a wind turbine generator. Ph.D. Thesis - Toledo Univ.

    Gilbert, L. J.


    In order to obtain a measure of its responses to short circuits a large horizontal axis wind turbine generator was modeled and its performance was simulated on a digital computer. Simulation of short circuit faults on the synchronous alternator of a wind turbine generator, without resort to the classical assumptions generally made for that analysis, indicates that maximum clearing times for the system tied to an infinite bus are longer than the typical clearing times for equivalent capacity conventional machines. Also, maximum clearing times are independent of tower shadow and wind shear. Variation of circuit conditions produce the modifications in the transient response predicted by analysis.

  6. Rheological Behavior and Microstructure of Ceramic Particulate/Aluminum Alloy Composites. Ph.D. Thesis Final Technical Report

    Moon, Hee-Kyung


    The rheological behavior and microstructure were investigated using a concentric cylinder viscometer for three different slurries: semi-solid alloy slurries of a matrix alloy, Al-6.5wt percent Si: composite slurries, SiC (sub p) (8.5 microns)/Al-6.5wt percent Si, with the same matrix alloy in the molten state, and composite slurries of the same composition with the matrix alloy in the semi-solid state. The pseudoplasticity of these slurries was obtained by step changes of the shear rate from a given initial shear rate. To study the thixotropic behavior of the system, a slurry was allowed to rest for different periods of time, prior to shearing at a given initial shear rate. In the continuous cooling experiments, the viscosities of these slurries were dependent on the shear rate, cooling rate, volume fraction of the primary solid of the matrix alloy, and volume fraction of silicon carbide. In the isothermal experiments, all three kinds of slurries exhibited non-Newtonian behavior, depending on the volume fraction of solid particles.

  7. An investigation of the SNS Josephson junction as a three-terminal device. Ph.D. Thesis

    Meissner, H.; Prans, G. P.


    A particular phenomenon of the SNS Josephson junction was investigated; i.e., control by a current entering the normal region and leaving through one of the superconducting regions. The effect of the control current on the junction was found to be dependent upon the ration of the resistances of the two halves of the N layer. A low frequency, lumped, nonlinear model was proposed to describe the electrical characteristics of the device, and a method was developed to plot the dynamic junction resistance as a function of junction current. The effective thermal noise temperature of the sample was determined. Small signal linearized analysis of the device suggests its use as an impedance transformer, although geometric limitations must be overcome. Linear approximation indicates that it is reciprocal and no power gain is possible. It is felt that, with suitable metallurgical and geometrical improvements, the device has promise to become a superconducting transistor.

  8. Experiments in cooperative-arm object manipulation with a two-armed free-flying robot. Ph.D. Thesis

    Koningstein, Ross


    Developing computed-torque controllers for complex manipulator systems using current techniques and tools is difficult because they address the issues pertinent to simulation, as opposed to control. A new formulation of computed-torque (CT) control that leads to an automated computer-torque robot controller program is presented. This automated tool is used for simulations and experimental demonstrations of endpoint and object control from a free-flying robot. A new computed-torque formulation states the multibody control problem in an elegant, homogeneous, and practical form. A recursive dynamics algorithm is presented that numerically evaluates kinematics and dynamics terms for multibody systems given a topological description. Manipulators may be free-flying, and may have closed-chain constraints. With the exception of object squeeze-force control, the algorithm does not deal with actuator redundancy. The algorithm is used to implement an automated 2D computed-torque dynamics and control package that allows joint, endpoint, orientation, momentum, and object squeeze-force control. This package obviates the need for hand-derivation of kinematics and dynamics, and is used for both simulation and experimental control. Endpoint control experiments are performed on a laboratory robot that has two arms to manipulate payloads, and uses an air bearing to achieve very-low drag characteristics. Simulations and experimental data for endpoint and object controllers are presented for the experimental robot - a complex dynamic system. There is a certain rather wide set of conditions under which CT endpoint controllers can neglect robot base accelerations (but not motions) and achieve comparable performance including base accelerations in the model. The regime over which this simplification holds is explored by simulation and experiment.

  9. Surveys of Ph.D. Thesis: Review of Doctoral Research in Language Assessment in Canada (2006-2011)

    Cheng, Liying; Fox, Janna


    This paper reviews a selected sample of 24 doctoral dissertations in language assessment (broadly defined), completed between 2006 and 2011 in Canadian universities. These dissertations fall into five thematic categories: 1) reliability, validity and factors affecting test performance; 2) washback (impact) and ethics; 3) raters, rating and rating…

  10. Response of the upper atmosphere to variations in the solar soft x-ray irradiance. Ph.D. Thesis

    Bailey, S.M.


    Terrestrial far ultraviolet (FUV) airglow emissions have been suggested as a means for remote sensing the structure of the upper atmosphere. The energy which leads to the excitation of FUV airglow emissions is solar irradiance at extreme ultraviolet (EUV) and soft x-ray wavelengths. Solar irradiance at these wavelengths is known to be highly variable; studies of nitric oxide (NO) in the lower thermosphere have suggested a variability of more than an order of magnitude in the solar soft x-ray irradiance. To properly interpret the FUV airglow, the magnitude of the solar energy deposition must be known. Previous analyses have used the electron impact excited Lyman-Birge-Hopfield (LBH) bands of N2 to infer the flux of photoelectrons in the atmosphere and thus to infer the magnitude of the solar irradiance. This dissertation presents the first simultaneous measurements of the FUV airglow, the major atmospheric constituent densities, and the solar EUV and soft x-ray irradiances. The measurements were made on three flights of an identical sounding rocket payload at different levels of solar activity. The linear response in brightness of the LBH bands to variations in solar irradiance is demonstrated. In addition to the N2 LBH bands, atomic oxygen lines at 135.6 and 130.4 nm are also studied. Unlike the LBH bands, these emissions undergo radiative transfer effects in the atmosphere. The OI emission at 135.6 nm is found to be well modeled using a radiative transfer calculation and the known excitation processes. Unfortunately, the assumed processes leading to OI 130.4 nm excitation are found to be insufficient to reproduce the observed variability of this emission. Production of NO in the atmosphere is examined; it is shown that a lower than previously reported variability in the solar soft x-ray irradiance is required to explain the variability of NO.

  11. Response of the upper atmosphere to variations in the solar soft x-ray irradiance. Ph.D. Thesis

    Bailey, Scott Martin


    Terrestrial far ultraviolet (FUV) airglow emissions have been suggested as a means for remote sensing the structure of the upper atmosphere. The energy which leads to the excitation of FUV airglow emissions is solar irradiance at extreme ultraviolet (EUV) and soft x-ray wavelengths. Solar irradiance at these wavelengths is known to be highly variable; studies of nitric oxide (NO) in the lower thermosphere have suggested a variability of more than an order of magnitude in the solar soft x-ray irradiance. To properly interpret the FUV airflow, the magnitude of the solar energy deposition must be known. Previous analyses have used the electron impact excited Lyman-Birge-Hopfield (LBH) bands of N2 to infer the flux of photoelectrons in the atmosphere and thus to infer the magnitude of the solar irradiance. This dissertation presents the first simultaneous measurements of the FUV airglow, the major atmospheric constituent densities, and the solar EUV and soft x-ray irradiances. The measurements were made on three flights of an identical sounding rocket payload at different levels of solar activity. The linear response in brightness of the LBH bands to variations in solar irradiance is demonstrated. In addition to the N2 LBH bands, atomic oxygen lines at 135.6 and 130.4 nm are also studied. Unlike the LBH bands, these emissions undergo radiative transfer effects in the atmosphere. The OI emission at 135.6 nm is found to be well modeled using a radiative transfer calculation and the known excitation processes. Unfortunately, the assumed processes leading to OI 130.4 nm excitation are found to be insufficient to reproduce the observed variability of this emission. Production of NO in the atmosphere is examined; it is shown that a lower than previously reported variability in the solar soft x-ray irradiance is required to explain the variability of NO.

  12. Processing and Mechanical Properties of NiAl-Based In-Situ Composites. Ph.D. Thesis Final Report

    Johnson, David Ray


    In-situ composites based on the NiAl-Cr eutectic system were successfully produced by containerless processing and evaluated. The NiAl-Cr alloys had a fibrous microstructure while the NiAl-(Cr,Mo) alloys containing 1 at. percent or more molybdenum exhibited a lamellar structure. The NiAl-28Cr-6Mo eutectic displays promising high temperature strength while still maintaining a reasonable room temperature fracture toughness when compared to other NiAl-based materials. The Laves phase NiAlTa was used to strengthen NiAl and very promising creep strengths were found for the directionally solidified NiAl-NiAlTa eutectic. The eutectic composition was found to be near NiAl-15.5Ta (at. percent) and well aligned microstructures were produced at this composition. An off-eutectic composition of NiAl-14.5Ta was also processed, consisting of NiAl dendrites surrounded by aligned eutectic regions. The room temperature toughness of these two phase alloys was similar to that of polycrystalline NiAl even with the presence of the brittle Laves phase NiAlTa. Polyphase in-situ composites were generated by directional solidification of ternary eutectics. The systems investigated were the Ni-Al-Ta-X (X=Cr, Mo, or V) alloys. Ternary eutectics were found in each of these systems and both the eutectic composition and temperature were determined. Of these ternary eutectics, the one in the NiAl-Ta-Cr system was found to be the most promising. The fracture toughness of the NiAl-(Cr,Al)NiTa-Cr eutectic was intermediate between those of the NiAl-NiAlTa eutectic and the NiAl-Cr eutectic. The creep strength of this ternary eutectic was similar to or greater than that of the NiAl-Cr eutectic.

  13. Damage Mechanisms and Controlled Crack Propagation in a Hot Pressed Silicon Nitride Ceramic. Ph.D. Thesis - Northwestern Univ., 1993

    Calomino, Anthony Martin


    The subcritical growth of cracks from pre-existing flaws in ceramics can severely affect the structural reliability of a material. The ability to directly observe subcritical crack growth and rigorously analyze its influence on fracture behavior is important for an accurate assessment of material performance. A Mode I fracture specimen and loading method has been developed which permits the observation of stable, subcritical crack extension in monolithic and toughened ceramics. The test specimen and procedure has demonstrated its ability to generate and stably propagate sharp, through-thickness cracks in brittle high modulus materials. Crack growth for an aluminum oxide ceramic was observed to be continuously stable throughout testing. Conversely, the fracture behavior of a silicon nitride ceramic exhibited crack growth as a series of subcritical extensions which are interrupted by dynamic propagation. Dynamic initiation and arrest fracture resistance measurements for the silicon nitride averaged 67 and 48 J/sq m, respectively. The dynamic initiation event was observed to be sudden and explosive. Increments of subcritical crack growth contributed to a 40 percent increase in fracture resistance before dynamic initiation. Subcritical crack growth visibly marked the fracture surface with an increase in surface roughness. Increments of subcritical crack growth loosen ceramic material near the fracture surface and the fracture debris is easily removed by a replication technique. Fracture debris is viewed as evidence that both crack bridging and subsurface microcracking may be some of the mechanisms contributing to the increase in fracture resistance. A Statistical Fracture Mechanics model specifically developed to address subcritical crack growth and fracture reliability is used together with a damaged zone of material at the crack tip to model experimental results. A Monte Carlo simulation of the actual experiments was used to establish a set of modeling input parameters. It was demonstrated that a single critical parameter does not characterize the conditions required for dynamic initiation. Experimental measurements for critical crack lengths, and the energy release rates exhibit significant scatter. The resulting output of the model produces good agreement with both the average values and scatter of experimental measurements.

  14. Interfacial Effects on the Thermal and Mechanical Properties of Graphite/Copper Composites. Final Contractor Report Ph.D. Thesis

    Devincent, Sandra Marie


    Graphite surfaces are not wet by pure copper. This lack of wetting has been responsible for a debonding phenomenon that has been found in continuous graphite fiber reinforced copper matrix composites subjected to elevated temperatures. By suitably alloying copper, its ability to wet graphite surfaces can be enhanced. Information obtained during sessile drop testing has led to the development of a copper-chromium alloy that suitably wets graphite. Unidirectionally reinforced graphite/copper composites have been fabricated using a pressure infiltration casting procedure. P100 pitch-based fibers have been used to reinforce copper and copper-chromium alloys. X-ray radiography and optical microscopy have been used to assess the fiber distribution in the cast composites. Scanning electron microscopy and Auger electron spectroscopy analyses were conducted to study the distribution and continuity of the chromium carbide reaction phase that forms at the fiber/matrix interface in the alloyed matrix composites. The effects of the chromium in the copper matrix on the mechanical and thermal properties of P100Gr/Cu composites have been evaluated through tensile testing, three-point bend testing, thermal cycling and thermal conductivity calculations. The addition of chromium has resulted in an increased shear modulus and essentially zero thermal expansion in the P100Gr/Cu-xCr composites through enhanced fiber/matrix bonding. The composites have longitudinal tensile strengths in excess of 700 MPa with elastic moduli of 393 GPa. After 100 hr at 760 deg C 84 percent of the as-cast strength is retained in the alloyed matrix composites. The elastic moduli are unchanged by the thermal exposure. It has been found that problems with spreading of the fiber tows strongly affect the long transverse tensile properties and the short transverse thermal conductivity of the P100Gr/Cu-xCr composites. The long transverse tensile strength is limited by rows of touching fibers which are paths of easy crack propagation under low tensile loads. The short transverse thermal conductivity is dictated by the fiber/matrix interface. Conduction across this interface has been estimated to be two orders of magnitude lower than that across the composite. This is due to the mechanical, and not chemical, nature of Gr/Cu bond.

  15. Inertial acceleration as a measure of linear vection: An alternative to magnitude estimation. Ph.D. Thesis

    Carpenter-Smith, Theodore R.; Futamura, Robert G.; Parker, Donald E.


    The present study focused on the development of a procedure to assess perceived self-motion induced by visual surround motion - vection. Using an apparatus that permitted independent control of visual and inertial stimuli, prone observers were translated along their head x-axis (fore/aft). The observers' task was to report the direction of self-motion during passive forward and backward translations of their bodies coupled with exposure to various visual surround conditions. The proportion of 'forward' responses was used to calculate each observer's point of subjective equality (PSE) for each surround condition. The results showed that the moving visual stimulus produced a significant shift in the PSE when data from the moving surround condition were compared with the stationary surround and no-vision condition. Further, the results indicated that vection increased monotonically with surround velocities between 4 and 40/s. It was concluded that linear vection can be measured in terms of changes in the amplitude of whole-body inertial acceleration required to elicit equivalent numbers of 'forward' and 'backward' self-motion reports.

  16. The Impact of Educational Interventions on Organizational Culture at an Urban Federal Agency. Ph.D. Thesis - Old Dominion Univ.

    Mckenzie, Janet Myrick


    This study on the impact of educational interventions on organizational culture is an evaluation of a major educational initiative undertaken by an urban federal agency, namely the National Aeronautics and Space Administration's Langley Research Center (NASA-LaRC). The design of this educational evaluation captures the essence of NASA-LaRC's efforts to continue its distinguished and international stature in the aeronautical research community following the Challenger tragedy. More specifically, this study is an evaluation of the educational initiative designed to ameliorate organizational culture via educational interventions, with emphasis on communications, rewards and recognition, and career development. After completing a review of the related literature, chronicling the educational initiative, interviewing senior managers and employees, and critically examining thousands of free responses on employee perceptions of organizational culture, it is found that previous definitions of organizational culture are more accurately classified as manifestations of organizational culture. This research has endeared to redefine 'organizational culture' by offering a more accurate and diagnostic perspective.

  17. Nial and Nial-Based Composites Directionally Solidified by a Containerless Zone Process. Ph.D. Thesis

    Joslin, Steven M.


    A containerless electromagnetically levitated zone (CELZ) process has been used to directionally solidify NiAl and NiAl-based composites. The CELZ processing results in single crystal NiAl (HP-NiAl) having higher purity than commercially pure NiAl grown by a modified Bridgman process (CP-NiAl). The mechanical properties, specifically fracture toughness and creep strength, of the HP-NiAl are superior to binary CP-NiAl and are used as a base-line for comparison with the composite materials subsequently studied. Two-phase composite materials (NiAl-based eutectic alloys) show improvement in room temperature fracture toughness and 1200 to 1400 K creep strength over that of binary HP-NiAl. Metallic phase reinforcements produce the greatest improvement in fracture toughness, while intermetallic reinforcement produces the largest improvement in high temperature strength. Three-phase eutectic alloys and composite materials were identified and directionally solidified with the intent to combine the improvements observed in the two-phase alloys into one alloy. The room temperature fracture toughness and high temperature strength (in air) serve as the basis for comparison between all of the alloys. Finally, the composite materials are discussed in terms of dominant fracture mechanism observed by fractography.

  18. Interlaminar stress analysis of dropped-ply laminated plates and shells by a mixed method. Ph.D. Thesis

    Harrison, Peter N.; Johnson, Eric R.; Starnes, James H., Jr.


    A mixed method of approximation based on Reissner's variational principle is developed for the linear analysis of interlaminar stresses in laminated composites, with special interest in laminates that contain terminated internal plies (dropped-ply laminates). Two models are derived, one for problems of generalized plane deformation and the other for the axisymmetric response of shells of revolution. A layerwise approach is taken in which the stress field is assumed with an explicit dependence on the thickness coordinate in each layer. The dependence of the stress field on the thickness coordinate is determined such that the three-dimensional equilibrium equations are satisfied by the approximation. The solution domain is reduced to one dimension by integration through the thickness. Continuity of tractions and displacements between layers is imposed. The governing two-point boundary value problem is composed of a system of both differential and algebraic equations (DAE's) and their associated boundary conditions. Careful evaluation of the system of DAE's was required to arrive at a form that allowed application of a one-step finite difference approximation. A two-stage Gauss implicit Runge-Kutta finite difference scheme was used for the solution because of its relatively high degree of accuracy. Patch tests of the two models revealed problems with solution accuracy for the axisymmetric model of a cylindrical shell loaded by internal pressure. Parametric studies of dropped-ply laminate characteristics and their influence on the interlaminar stresses were performed using the generalized plane deformation model. Eccentricity of the middle surface of the laminate through the ply drop-off was found to have a minimal effect on the interlaminar stresses under longitudinal compression, transverse tension, and in-plane shear. A second study found the stiffness change across the ply termination to have a much greater influence on the interlaminar stresses.

  19. Studies of Two-Phase Gas-Liquid Flow in Microgravity. Ph.D. Thesis, Dec. 1994

    Bousman, William Scott


    Two-phase gas-liquid flows are expected to occur in many future space operations. Due to a lack of buoyancy in the microgravity environment, two-phase flows are known to behave differently than those in earth gravity. Despite these concerns, little research has been conducted on microgravity two-phase flow and the current understanding is poor. This dissertation describes an experimental and modeling study of the characteristics of two-phase flows in microgravity. An experiment was operated onboard NASA aircraft capable of producing short periods of microgravity. In addition to high speed photographs of the flows, electronic measurements of void fraction, liquid film thickness, bubble and wave velocity, pressure drop and wall shear stress were made for a wide range of liquid and gas flow rates. The effects of liquid viscosity, surface tension and tube diameter on the behavior of these flows were also assessed. From the data collected, maps showing the occurrence of various flow patterns as a function of gas and liquid flow rates were constructed. Earth gravity two-phase flow models were compared to the results of the microgravity experiments and in some cases modified. Models were developed to predict the transitions on the flow pattern maps. Three flow patterns, bubble, slug and annular flow, were observed in microgravity. These patterns were found to occur in distinct regions of the gas-liquid flow rate parameter space. The effect of liquid viscosity, surface tension and tube diameter on the location of the boundaries of these regions was small. Void fraction and Weber number transition criteria both produced reasonable transition models. Void fraction and bubble velocity for bubble and slug flows were found to be well described by the Drift-Flux model used to describe such flows in earth gravity. Pressure drop modeling by the homogeneous flow model was inconclusive for bubble and slug flows. Annular flows were found to be complex systems of ring-like waves and a substrate film. Pressure drop was best fitted with the Lockhart- Martinelli model. Force balances suggest that droplet entrainment may be a large component of the total pressure drop.

  20. Spectroscopic studies of the exhaust plume of a quasi-steady MPD accelerator. Ph.D. Thesis

    Bruckner, A. P.


    Spectroscopic and photographic investigations are reported that reveal a complex azimuthal species structure in the exhaust plume of a quasi-steady argon MPD accelerator. Over a wide range of operating conditions the injected argon remains collimated in discrete jets which are azimuthally in line with the six propellant injector orifices. The regions between these argon jets, including the central core of the exhaust flow, are occupied by impurities such as carbon, hydrogen and oxygen ablated from the Plexiglas back plate of the arc chamber. The features of this plume structure are found to be dependent on the arc current and mass flow rate. It is found that nearly half the observed velocity is attained in an acceleration region well downstream of the region of significant electromagnetic interaction. Recombination calculations show that the ionization energy is essentially frozen.

  1. An investigation of satellites to the resonance lines in some hydrogen-like ions. Ph.D. Thesis - Colo. Univ.

    Jalufka, N. W.


    An experimental and theoretical investigation was conducted on the origin of satellite to resonance lines of the hydrogen-like ions of boron, carbon, and nitrogen. A theta pinch was employed with a grazing incidence spectrograph to measure the wavelengths of the satellites. The spectroscopic data also provided an estimate of the satellite/resonance line intensity ratio. Wavelengths of spectral lines due to transition from doubly excited states were calculated by a Hartree-Fock computer program. Wave functions were also calculated and were used to obtain the oscillator strengths of the transitions. Experimental work confirmed that the lines investigated were not satellites but were due to highly ionized argon which was present as an impurity in the filling gas.

  2. The effect of variable calcium and very low calcium diets on human calcium metabolism. Ph.D. Thesis. Final Report

    Chu, J.


    The effects of a very low calcium diet, with variable high and low protein intake, on the dynamics of calcium metabolism and the mechanism of calciuretics, are examined. The experiment, using male subjects, was designed to study the role of intestinal calcium absorption on urinary calcium excretion, and the rate of production of endogeneously secreted calcium in the gastrointestinal tract. The study showed an average of 70% fractional absorption rate during very low calcium intake, and that a decrease in renal tubular reabsorption of calcium is responsible for calciuretic effects of high protein intake. The study also indicates that there is a tendency to develop osteoporosis after long periods of low calcium intake, especially with a concurrent high protein intake.

  3. Patients' Obligation, Embodiment, Motives, and Self in Hypertension - a Qualitative Study from General Practice (PhD thesis)

    Sångren, Henrik

    Resume: Afhandlingen besk‘ftiger sig med hvordan patienter oplever at blive diagnosticeret med forh›jet blodtryk (hypertension). Unders›gelsen unders›ger hvilke motiver der bev‘ger patienter til at acceptere medicinsk behandling af deres forh›jede blodtryk, og hvorledes de oplever livet med...... patientens opfattelse af eget Selv. Ved brug af Interpretative Phenomenological Analysis (IPA) analyseres patienters motiv for accept af medicinsk behandling af forh›jet blodtryk. En del af afhandlingen benytter forskerens muligheder of refleksivitet og humanistiske teorier til at n† til en forskningsm......‘ge-patient forholdet. Alle resultater fra dette studie blev diskuteret ud fra denne pr‘mis. Form†l Det overordnede form†l med studiet var at unders›ge hvordan patienter oplever at blive diagnosticeret som havende forh›jet blodtryk. Patientens motiv for at acceptere medicinsk behandling for tilstanden blev unders...

  4. Surface films and metallurgy related to lubrication and wear. Ph.D. Thesis - Tokyo Inst. of Technology

    Buckley, D. H.


    The nature of the tribological surface is identified and characterized with respect to adhesion, friction, wear, and lubricating properties. Surface analysis is used to identify the role of environmental constituents on tribological behavior. The effect of solid to solid interactions for metals in contact with metals, ceramics, semiconductors, carbons, and polymers is discussed. The data presented indicate that the tribological surface is markedly different than an ideal solid surface. The environment is shown to affect strongly the behavior of two solids in contact. Results also show that small amounts of alloying elements in base metals can alter markedly adhesion, friction, and wear by segregating to the solid surface.

  5. The Bulk Lunar Electrical Conductivity. Ph.D. Thesis. Final Report; [from Explorer 35 satellite and the Apollo 12 flight

    Leavy, Donald Lucien


    The electrical conductivity structure was studied of a spherically layered moon consistent with the very low frequency magnetic data collected on the lunar surface and by Explorer 35. In order to obtain good agreement with the lunar surface magnetometer observations, the inclusion of a void cavity behind the moon requires a conductivity at shallow depths higher than that of models having the solar wind impinging on all sides. By varying only the source parameters, a conductivity model can be found that yields a good fit to both the tangential response upstream and the radial response downstream. This model also satisfies the dark side tangential response in the frequency range above 0.006 Hz, but the few data points presently available below this range do not seem to agree with the theory.

  6. Aeroelastic response and stability of tiltrotors with elastically-coupled composite rotor blades. Ph.D. Thesis

    Nixon, Mark W.


    There is a potential for improving the performance and aeroelastic stability of tiltrotors through the use of elastically-coupled composite rotor blades. To study the characteristics of tiltrotors with these types of rotor blades it is necessary to formulate a new analysis which has the capabilities of modeling both a tiltrotor configuration and an anisotropic rotor blade. Background for these formulations is established in two preliminary investigations. In the first, the influence of several system design parameters on tiltrotor aeroelastic stability is examined for the high-speed axial flight mode using a newly-developed rigid-blade analysis with an elastic wing finite element model. The second preliminary investigation addresses the accuracy of using a one-dimensional beam analysis to predict frequencies of elastically-coupled highly-twisted rotor blades. Important aspects of the new aeroelastic formulations are the inclusion of a large steady pylon angle which controls tilt of the rotor system with respect to the airflow, the inclusion of elastic pitch-lag coupling terms related to rotor precone, the inclusion of hub-related degrees of freedom which enable modeling of a gimballed rotor system and engine drive-train dynamics, and additional elastic coupling terms which enable modeling of the anisotropic features for both the rotor blades and the tiltrotor wing. Accuracy of the new tiltrotor analysis is demonstrated by a comparison of the results produced for a baseline case with analytical and experimental results reported in the open literature. Two investigations of elastically tailored blades on a baseline tiltrotor are then conducted. One investigation shows that elastic bending-twist coupling of the rotor blade is a very effective means for increasing the flutter velocity of a tiltrotor, and the magnitude of coupling required does not have an adverse effect on performance or blade loads. The second investigation shows that passive blade twist control via elastic extension-twist coupling of the rotor blade has the capability of significantly improving tiltrotor aerodynamic performance. This concept, however, is shown to have, in general, a negative impact on stability characteristics.

  7. The performance of a seasonal global climatic model. Ph.D. Thesis - MIT; [seasonal cycle of the temperature

    Robock, A.


    A seasonal global climatic model developed by Sellers is studied. Several changes are made to correct errors in the original model and to allow its use in a time dependent simulation mode. The major changes are in the infrared radiation formulation and in the size of the time steps. The seasonal cycles of surface temperature, wind, ice, snow, albedo, horizontal heat transport, and vertical flux of solar and infrared radiation are compared to recent observations. The seasonal cycle of temperature is fairly well reproduced, but has too small an amplitude in the Northern Hemisphere high latitudes. An overestimate of albedo at the poles is found, which is related to errors in some of the other variables. The sensitivity of the model to CO2 and solar constant (O) changes is summarized. Doubling the CO2 amount causes a 2.45 K increase in global average surface temperature (T). Increasing Q by 1% increases T by 3.14K. Decreasing 0 by 1% decreases T by 4.65K. An annual average version of the model is more sensitive to changes in Q than the model with the seasonal cycle.

  8. Mapping unstructured grid computations to massively parallel computers. Ph.D. Thesis - Rensselaer Polytechnic Inst., Feb. 1992

    Hammond, Steven Warren


    Investigated here is this mapping problem: assign the tasks of a parallel program to the processors of a parallel computer such that the execution time is minimized. First, a taxonomy of objective functions and heuristics used to solve the mapping problem is presented. Next, we develop a highly parallel heuristic mapping algorithm, called Cyclic Pairwise Exchange (CPE), and discuss its place in the taxonomy. CPE uses local pairwise exchanges of processor assignments to iteratively improve an initial mapping. A variety of initial mapping schemes are tested and recursive spectral bipartitioning (RSB) followed by CPE is shown to result in the best mappings. For the test cases studied here, problems arising in computational fluid dynamics and structural mechanics on unstructured triangular and tetrahedral meshes, RSB and CPE outperform methods based on simulated annealing. Much less time is required to do the mapping and the results obtained are better. Compared with random and naive mappings, RSB and CPE reduce the communication time two fold for the test problems used. Finally, we use CPE in two applications on a CM-2. The first application is a data parallel mesh-vertex upwind finite volume scheme for solving the Euler equations on 2-D triangular unstructured meshes. CPE is used to map grid points to processors. The performance of this code is compared with a similar code on a Cray-YMP and an Intel iPSC/860. The second application is parallel sparse matrix-vector multiplication used in the iterative solution of large sparse linear systems of equations. We map rows of the matrix to processors and use an inner-product based matrix-vector multiplication. We demonstrate that this method is an order of magnitude faster than methods based on scan operations for our test cases.

  9. Reflecting Solutions of High Order Elliptic Differential Equations in Two Independent Variables Across Analytic Arcs. Ph.D. Thesis

    Carleton, O.


    Consideration is given specifically to sixth order elliptic partial differential equations in two independent real variables x, y such that the coefficients of the highest order terms are real constants. It is assumed that the differential operator has distinct characteristics and that it can be factored as a product of second order operators. By analytically continuing into the complex domain and using the complex characteristic coordinates of the differential equation, it is shown that its solutions, u, may be reflected across analytic arcs on which u satisfies certain analytic boundary conditions. Moreover, a method is given whereby one can determine a region into which the solution is extensible. It is seen that this region of reflection is dependent on the original domain of difinition of the solution, the arc and the coefficients of the highest order terms of the equation and not on any sufficiently small quantities; i.e., the reflection is global in nature. The method employed may be applied to similar differential equations of order 2n.

  10. Perturbation theory of structure in classical liquid mixtures: Application to metallic systems near phase separation. Ph.D. Thesis

    Henderson, R. L.


    The partial structure factors of classical simple liquid mixtures near phase separation are dicussed. The theory is developed for particles interacting through pair potentials, and is thus appropriate both to insulating fluids, and also to metallic systems if these may be described by an effective ion-ion pair interaction. The motivation arose from consideration of metallic liquid mixtures, in which resistive anomalies have been observed near phase separation. A mean field theory correction appropriate to 3 pair potential for the effects of correlated motions in the reference fluid is studied. The work is cast in terms of functions which are closely related to the direct correlation functions of Ornstein and Zernike. The results are qualitatively in accord with physical expectations. Quantitative agreement with experiment seems to turn on the selection of the hard core reference potential in terms of the metallic effective pair potential. It is suggested that the present effective pair potentials are perhaps not properly used to calculate the metallic structure factors at long wavelength.