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It has been recognized for some years that the use of computer graphics systems has great potential for improving man/computer communication. In the past, however, the high cost of graphics hardware, and the lack of accepted principles for graphics programming, prevented the widespread use of such systems. Recently, hardware has become more readily available, and efforts have been made to develop graphics software standards. This report presents an overview of one of the proposed standards, the Core System, and also discusses a portable subroutine library, based on the the Core System, that has been developed for use at McMaster University. This library, called SSOCS, is written in Pascal, and allows a user to produce two-dimensional images without regard to the characteristics of the graphics devices being used. / Thesis / Master of Science (MS)

This study extends job embeddedness and job satisfaction theory in several notable directions. As hypothesized, structural equation modeling revealed that community embeddedness was a partial mediator of the relationship between core self-evaluations and job satisfaction. Contrary to job embeddedness theory, this study found that organizational embeddedness and job satisfaction were best represented by a single latent factor. Thus, organizational embeddedness did not act as a mediator of the relationship between core self-evaluations and job satisfaction nor did it act as a multiple mediator with community embeddedness. Explanations of these results and new avenues for research are discussed. / Ph. D.

No / Composite structure incorporating steel beams and precast hollowcore slabs is a recently developed composite floor system for building structures. This form of composite construction is so far limited to simple beam-column connections. Although the concept of semi-rigid composite joints has been widely research in the past, most of the researches have been carried out on composite joints with metal deck flooring and solid concrete slabs. Research on composite joints with precast hollowcore slabs is rather limited. As the construction industry demands for rapid construction with reduction in cost and environmental impacts, this form of composite floor system, which does not require major onsite concreting, has become very popular among the designers and engineers in the UK. In this paper, full-scale tests of beam-to-column semi-rigid composite joints with steel beam and precast hollowcore slabs are reported. Based on the tests data; the structural behaviour of these semi-rigid composite joints is discussed together with numerical and finite element modelling. Through parametric studies, an analytical model for the semirigid composite joints is proposed and is verified by both the experimental data and finite element model; and good agreement is obtained.

Cellular core structures are the state-of-the-art technology for light weight structures in the aerospace industry. In an aerospace product, sandwich panels with cellular core represent the primary structural component as a given aerospace product may contain a large number of sandwich panels. This reveals the necessity of understanding the mechanical behavior of the cellular core and the impact of that behavior on the overall structural behavior of the sandwich panel, and hence the final aerospace product. As the final aerospace product must go through multiple qualification tests to achieve a final structure that is capable of withstanding all environments possible, analyzing the structure prior to testing is very important to avoid any possible failures and to ensure that the final design is indeed capable of withstanding the loads. To date, due to the lack of full understanding of the mechanical behavior of cellular cores and hence the sandwich panels, there still remains a significant lack of analytical capability to predict the proper behavior of the final product and failures may still occur even with significant effort spent on pre-test analyses. Analyzing cellular core to calculate the equivalent material properties of this type of structure is the only way to properly design the core for sandwich enhanced stiffness to weight ratio of the sandwich panels. A detailed literature review is first conducted to access the current state of development of this research area based on experiment and analysis. Then, one of the recently developed homogenization schemes is chosen to investigate the mechanical behavior of heavy, non-corrugated square cellular core with a potential application in marine structures. The mechanical behavior of the square cellular core is then calculated by applying the displacement approach to a representative unit cell finite element model. The mechanical behavior is then incorporated into sandwich panel finite element model and in an in-house code to test the predicted mechanical properties by comparing the center-of-panel displacement from all analyses to that of a highly detailed model. The research is then expanded to cover three cellular core shapes, hexagonal cores made of corrugated sheets, square cores made of corrugated sheets, and triangular cores. The expansion covers five different cell sizes and twenty one different core densities for each of the core shapes considering light cellular cores for space applications, for a total of 315 detailed studies. The accuracy of the calculated properties for all three core shapes is checked against highly detailed finite element models of sandwich panels. Formulas are then developed to calculate the mechanical properties of the three shapes of cellular cores studied for any core density and any of the five cell sizes. An error analysis is then performed to understand the quality of the predicted equivalent properties considering the panel size to cell size ratio as well as the facesheet thickness to core thickness ratio. The research finally expanded to understand the effect of buckling of the unit cell on the equivalent mechanical property of the cellular core. This part of the research is meant to address the impact of the local buckling that may occur due to impact of any type during the manufacturing, handling or assembly of the sandwich panels. The variation of the equivalent mechanical properties with the increase in transverse compression load, until the first folding of the unit cell is complete, is calculated for each of the three core shapes under investigation. / Ph. D.

Design of magnetic component is a key factor in achieving high frequency, high power-density converters. Planar magnetics are widely used in bias power supplies for the benefits of low profile and their compatibility with printed-circuit boards (PCB). The coupled inductors with winding layers sandwiched between two core plates are studied in this dissertation in order to model the self-inductance, winding loss, and core loss. The most challenging task for the plate-core inductor is to model the magnetic field with finite core dimensions, very non-uniform flux pattern, and large fringing flux. The winding is placed near the edge of the core to maximize the energy within the limited footprint and the amount of energy stored outside the core volume is not negligible. The proportional-reluctance, equal-flux (PREF) model is developed to build the contours with equal amount of flux by governing the reluctance of the flux path. The shapes of the flux lines are modeled by different functions that guided by the finite-element simulation (FES). The field from the flux lines enables calculation of inductance, winding loss, and core loss, etc. The inductance matrix including self-inductance and mutual inductance of a coupled inductor is important for circuit simulation and evaluation. The derivation of the inductance matrix of inductors with plate-core structure is described in Chapter 2. Two conditions are defined as common-mode (CM) field and differential-mode (DM) field in order to compute the matrix parameters. The proportional-reluctance, equal-flux (PREF) model introduced is employed to find the CM field distribution, and the DM field distribution is found from functions analogous to that of a solenoid's field. The inductance calculated are verified by flex-circuit prototypes with various dimensions, and the application of the inductance model is presented at the last with normalized parameters to cover structures within a wide-range. In circuit where coupled inductors are used instead of transformers, the phase shift between the primary and secondary side is not always 180 degrees. Therefore, it is important to model the winding loss for a coupled inductor accurately. The winding loss can be calculated from the resistance matrix, which is independent of excitations but only relates to the frequency and geometry. The methodology to derive the resistance matrix from winding losses of coupled inductors is discussed. Winding loss model with 2D magnetic field is improved by including the additional eddy current loss for better accuracy for the plate-core structures. The resistance matrix calculated from the model is verified by both measurement results and finite-element simulation (FES) of coupled-inductor prototypes. Accurate core loss model is required for designing magnetic components in power converters. Most existing core loss models are based on frequency domain calculation and they cannot be implemented in SPICE simulations. The core loss model in the time domain is discussed in Chapter 5 for arbitrary current excitations. An effective ac flux density is derived to simplify the core loss calculation with non-uniform field distribution. A sub-circuit for core loss simulation is established in LTSPICE that is capable of being integrated to the power stage simulation. Transient behavior and accurate simulation results from the LTSPICE matches very well with the FES results. An equivalent circuit for coupled windings is developed for inductors with significant fringing effect. The equivalent circuit is derived from a physical model that captures the flux paths by having a leakage inductor and two mutual inductors on the primary and secondary side. A mutual resistor is added to each side in parallel with one mutual inductor to model the winding loss with open circuit and phase-shift impact. Two time-varying resistors are employed to represent the core loss in the time-domain. The equivalent circuit is verified by both finite-element simulation (FES) and prototypes fabricated with flexible circuit. / Ph. D. / Compact power supplies requires low profile, high quality magnetic components such as inductors and two-winding inductors in order to achieve high efficiency and high density. The plate-core inductors comprise multilayer windings sandwiched by two core plates on the top and bottom, and the total thickness of the inductor is significantly smaller than the conventional surface-mount inductors. A model based on physical examination of the flux pattern is developed to calculate the magnetic field distribution of the plate-core inductor. The other performance factors such as inductance, winding loss, and core loss can also be calculated from the field distribution. An improved equivalent circuit is developed in order to simulate the voltage and current of the inductor in an arbitrary circuit. Compared to conventional equivalent circuit, the improved model includes the winding-loss variation with asymmetric current excitations. A core-loss sub-circuit is developed in SPICE simulation tools so that no finite-element simulations (FES) are required to obtain the core loss in the time domain, and the cost of time is reduced by more than 80%. A prototype is fabricated with inductors of different geometrical dimensions to verify the equivalent circuit under small signal condition. Good correlations among calculation, FES, and measurement are obtained with less than 13% error.

Piezoelectric material based sensors are widely used in applications such as automobiles, aircraft, and industrial systems. In past decade, attention has been focused on synthesizing composites that can provide multifunctional properties, i.e., same material exhibits two or more properties. In this group of composites, magnetoelectric materials are particularly interesting as they provide the opportunity of coupling magnetic and electric field. Another class of composite materials that are being actively pursued is piezoresistive materials. Piezoresistivity refers to change in resistance with applied stress and these materials are promising for enhancing the sensitivity of current generation pressure sensors based on silicon. In this study, we focus on two composites systems: ferrite / Terfenol-D / nickel — lead zirconate titanate (magnetoelectric); and lanthanum strontium manganate (LSMO) — carbon nanotube (CNT) – silicon carbonitride (SiCN) (piezoresistive). Recently, Islam et al. have reported a magnetic field sensor based on a piezoelectric transformer with a ring- dot electrode pattern. In this thesis, this design was further investigated by synthesizing Terfenol-D / PZT laminate. The fabricated sensor design consists of a ring-dot piezoelectric transformer laminated to a magnetostrictive disc and its working principle is as follows: When a constant voltage is applied to the ring section of the piezoelectric layer at resonance, a stress is induced in the dot section. Then, if an external magnetic object is introduced in the vicinity of the dot section, the effective elastic stiffness is increased, altering the resonance frequency (fr). The variation of resonance frequency and magnitude of output voltage with applied magnetic field was characterized and analyzed to determine the sensitivity. The sensor showed a shift of ~1.36Hz/Oe over the frequency range of 137.4<fr<144.2 kHz with increasing magnetic bias from 1<Hdc<6kOe. Next, in order to overcome the need of magnetic DC bias in current magnetoelectric composites, a metal – ceramic core-shell composite structure was investigated. Metal-ceramic composite particles were synthesized at room temperature and their magnetic properties were investigated. The particles constitute a core-shell structure where the core is nickel-metal, while the shell is manganese zinc ferrite (MZF). Coprecipitation was used for synthesis of MZF nanoparticles comprising the shell, whereas nickel was synthesized by hydrazine assisted reduction of nickel ions in aqueous media. A core shell structure was then obtained by hetero-coagulation to form a shell of MZF around the nickel particles. Electron microscopy and x-ray diffraction confirmed nickel cores coated by MZF shells. Magnetization studies of MZF nano-particles revealed that they were not super-paramagnetic at room temperature, as expected for such particle sizes of 20nm in size. Sintered composites of metal-ceramic particles core-shell exhibited a magnetostriction of 5ppm. Lastly, the thesis investigates the piezoresistive properties of LSMO – CNT – SiCN composites that were synthesized by the conventional ceramic sintering technique. Recent investigations have shown that CNTs and SiCN have high piezoresistive coefficient. DSC/TGA results showed that pure CNTs decompose at temperatures of ~600°C, however, SiCN was found to sustain the sintering temperature of 1300°C. Thus, LSMO – SiCN composites were used for the final analysis. A fractional resistivity change of 4% was found for LSMO — 12.5 vol% SiCN composites which is much higher compared to that of unmodified LSMO. / Master of Science

Yes / There are more than 200 published species within the Lactobacillus genus complex (LGC), the majority of which have sequenced type strain genomes available. Although genome-based species delimitation cutoffs are accepted as the gold standard by the community, these are seldom actually checked for new or already published species. In addition, the availability of genome data is revealing inconsistencies in the species-level classification of many strains. We constructed a de novo species taxonomy for the LGC based on 2,459 publicly available genomes, using a 94% core nucleotide identity cutoff. We reconciled these de novo species with published species and subspecies names by (i) identifying genomes of type strains and (ii) comparing 16S rRNA genes of the genomes with 16S rRNA genes of type strains. We found that genomes within the LGC could be divided into 239 de novo species that were discontinuous and exclusive. Comparison of these de novo species to published species led to the identification of nine sets of published species that can be merged and one species that can be split. Further, we found at least eight de novo species that constitute new, unpublished species. Finally, we reclassified 74 genomes on the species level and identified for the first time the species of 98 genomes. Overall, the current state of LGC species taxonomy is largely consistent with genome-based species delimitation cutoffs. There are, however, exceptions that should be resolved to evolve toward a taxonomy where species share a consistent diversity in terms of sequence divergence. / This study was supported by the Research Foundation Flanders (grant 11A0618N), the Flanders Innovation and Entrepreneurship Agency (grants IWT-SB 141198 and IWT/50052), and the University of Antwerp (grant FFB150344).

Inledning: Inom ISTDP har psykodynamisk diagnostik utvecklats och används kontinuerligt i behandlingen. Diagnostiken delar in patienter i olika karaktärsstrukturer. Frederickson (2013) gör en indelning i de fyra kategorierna lågt motstånd, moderat motstånd, högt motstånd och skör. Föreliggande studie undersöker hur patienters bedömda karaktärsstruktur samvarierar med patientens självskattning av sina psykiska besvär.  Frågeställningar: Samvarierar terapeutens bedömning avseende karaktärsstrukturerna lågt motstånd, moderat motstånd, högt motstånd och skör med patientens självskattade psykiska besvär med utvärderingsformuläret CORE-OM.  Metod: 31 patienter på tre olika psykiatriska mottagningar har fyllt i självskattningsformuläret CORE-OM. Därefter intervjuades de av psykolog för att bedöma karaktärsstruktur. Den fastställda karaktärsstrukturen jämfördes med utfall i CORE-OM. De statistiska analyserna har genomförts med Spearmans rho värde. Kruskal - Wallis rangordningstest. Vald signifikansnivå &lt; 0.05. Uppföljande parvisa post/hoc test (Man-Whitney U test med Bonferoni korrigerat p värde).  Resultat: Bedömd karaktärsstruktur samvarierar med patientens självskattning av psykiska besvär mätt med CORE-OM. Skillnaderna är signifikanta mellan karaktärstrukturerna moderat motstånd och skör avseende både CORE-OM total- och domänpoäng. Karaktärsstrukturen skör skiljer ut sig signifikant från övriga i domänen risk med högre grad av risk rapporterad. Karaktärsstrukturen moderat motstånd skiljer ut sig signifikant med rapporterat lägre grad av svårigheter i underkategorierna nära relationer och socialt i förhållande till övriga.  Diskussion: Studiens resultat påvisar att bedömning av karaktärsstruktur utifrån ISTDP är en tillförlitlig diagnostisk metod. Resultatet stödjer den långa traditionen av teoribildning inom den psykodynamiska traditionen vad gäller koppling mellan art av försvar och graden av psykisk ohälsa. / Introduction: In ISTDP have psychodynamic diagnostics developed and is continuously used in the treatment. The diagnostics divides patients into different character structures. Frederickson (2013) makes a classification into these four categories low resistance, moderate resistance, high resistance and fragile. This study examines how patients assessed character structure correlates with the patient's self-assessment of their mental problems. Questions: Does therapist's assessment correlate, concerning the nature of the structures low resistance, moderate resistance, high resistance and fragile, with the patient's self-rated mental health problems with the evaluation form CORE-OM. Methods: 31 patients at three psychiatric clinics have completed the self-assessment form CORE-OM. Then they were interviewed by the psychologists to assess the character of the structure. The estimated structure was compared with the outcomes of the CORE-OM. The statistical analyzes were conducted with Spearman's rho value. Kruskal - Wallis rank test. Selected level of significance &lt;0:05. Follow-up pairwise mail / hoc test (Man-Whitney U test with Bonferoni corrected p value). Results: The estimated character structure correlates with the patient's self-assessment of psychological disorders as measured by the CORE-OM. The differences are significant between character structures moderate resistance and fragile regard both the CORE-OM total and domain scores. Fragile character structure stands out significantly from the rest of the domain risk with higher degree of risk reported. Character Structure moderate resistance stands out significantly with reported lower degree of difficulty in subcategories close relationships and socially with the rest. Discussion: The study's results demonstrate that the assessment of the character structure based ISTDP is a reliable diagnostic method. The results support the long tradition of theory in the psychodynamic tradition of the link between the nature of the defense and the level of mental illness.