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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Surface and geometrical effect on the punch-through device

Liu, Bin, 1957- January 1988 (has links)
The punch-through space-charge-limited load (PTSCLL) may be an alternate VLSI design as a high resistance load device. A surface and geometrical study on the PTSCLL device is presented. From this research, it is found out that the dynamic resistance value increases as the surface bias to a negatively voltage. Also, the resistance increases as the channel length and substrate doping increase. But the resistance value decreases as the channel width, junction depth, and overlap oxide thickness increase. Incorporate these design considerations, it can maximize the resistance value of the PTSCLL.
22

Hydrological controls on shallow mass movements and characteristic slope forms in the tropical rainforest of Temburong District, Brunei

Dykes, Alan Philip January 1994 (has links)
No description available.
23

Uniform random planar graphs with degree constraints

Dowden, Christopher Thomas January 2008 (has links)
Random planar graphs have been the subject of much recent work. Many basic properties of the standard uniform random planar graph $P_{n}$, by which we mean a graph chosen uniformly at random from the set of all planar graphs with vertex set $ { 1,2, ldots, n }$, are now known, and variations on this standard random graph are also attracting interest. Prominent among the work on $P_{n}$ have been asymptotic results for the probability that $P_{n}$ will be connected or contain given components/ subgraphs. Such progress has been achieved through a combination of counting arguments cite{mcd} and a generating function approach cite{gim}. More recently, attention has turned to $P_{n,m}$, the graph taken uniformly at random from the set of all planar graphs on ${ 1,2, ldots, n }$ with exactly $m(n)$ edges (this can be thought of as a uniform random planar graph with a constraint on the average degree). In cite{ger} and cite{gim}, the case when $m(n) =~!lfloor qn floor$ for fixed $q in (1,3)$ has been investigated, and results obtained for the events that $P_{n, lfloor qn floor}$ will be connected and that $P_{n, lfloor qn floor}$ will contain given subgraphs. In Part I of this thesis, we use elementary counting arguments to extend the current knowledge of $P_{n,m}$. We investigate the probability that $P_{n,m}$ will contain given components, the probability that $P_{n,m}$ will contain given subgraphs, and the probability that $P_{n,m}$ will be connected, all for general $m(n)$, and show that there is different behaviour depending on which `region' the ratio $rac{m(n)}{n}$ falls into. In Part II, we investigate the same three topics for a uniform random planar graph with constraints on the maximum and minimum degrees.
24

Design of a planar biaxial mechanical testing device for soft biological tissues

January 2017 (has links)
acase@tulane.edu / The application of continuum mechanics principles to biological tissues is paramount to understanding (patho)physiological changes in tissue structure and function. Experimental and mathematical approaches can be utilized to quantify tissue mechanical behavior. In particular, planar biaxial mechanical testing of soft tissues (i.e. applying loads or deformation along two axes in the same plane) has proven to mimic physiologically relevant conditions for most soft tissues. Constitutive relations can then be formulated based on biaxial data to describe and predict soft tissue mechanical behavior. These mathematical tools could aid in delineating underlying mechanisms of and evaluating treatments for various clinically relevant issues. Therefore, the overall objective of this thesis is to build a custom planar biaxial mechanical testing device to characterize the mechanical properties of soft biological tissues to identify appropriate constitutive relations. A custom planar biaxial mechanical testing device was successfully built and validated. A LabVIEW program was written to interface with the stepper motors and load cells of the device to control their movements. A mechanical testing protocol was developed and incorporated to enable the characterization of a variety of soft tissue structure-function relationships. Foundations were laid for studies using the planar biaxial device for research in a tissue-engineered nipple-areolar complex (NAC), pelvic floor disorders, and age-specific tendinopathy. The planar biaxial device has the potential to impact many areas of clinical research. / 1 / Taylor McCrady
25

Design, Construction, and Validation of a Planar Biaxial Device for Mechanical Testing of Soft Tissue

January 2017 (has links)
acase@tulane.edu / Soft tissue mechanics attempts to describe biological tissues such as skin, tendon, and the reproductive organs using concepts found in mechanical engineering. By approaching soft tissues using this framework, the complex biomechanical response of such tissues, which have been implicated in the development of disease and injury, can be ascertained and quantified. Robust mechanical tests, in which tissue stress-strain behavior is characterized, are needed in order to inform constitutive models of healthy and diseased tissue. The overall objective of this thesis was to design, construct, program, and validate a planar biaxial device capable of testing soft tissues. Improvements and redesigns were made to the device to better suit the nature of testing required for soft tissue. Custom grips, modules, and software were developed and fabricated to facilitate accurate biaxial mechanical tests. Optimized for testing of small soft tissues, the biaxial device is an evolution of the standard approach towards mechanical testing. The overall device and the individual systems were validated internally and externally. Pilot studies were conducted on murine skin, compared to existing data from literature, and observed to correspond with known stress-strain and load-displacement properties. Further, experimental protocols were developed to evaluate the biaxial behavior of soft tissues, including cervical, uterine, vaginal, and uterosacral ligament tissue. Studies were described in which experimental data could be used to establish structure-function relationships describing reproductive tissue. Results from these studies could be used to elucidate the underlying mechanical etiologies of preterm birth and pelvic organ prolapse. / 1 / Jonathan Nguyen
26

Displaying cliques in graph drawings

Yamamoto, Yosuke 19 September 2010
Relational information represented by graphs can be found in various areas. Understanding completely connected groups of items is useful in studying relational information. However, when displayed in the form of a graph drawing, completely connected graphs contain quadratically many edges relative to the number of their vertices. This may increase the difficulty in identifying useful information, such as maximal cliques, in the graph. This thesis attempts to display the maximal cliques and the cliques contained in two or more maximal cliques in a given graph in an explicit and clear fashion. In order to achieve the goal, the thesis defines two models, the clique-star and the reduced-clique-star, that represent given input graphs. Both representations reduce the number of edges of the original graphs while maintaining the information about the maximal cliques. This thesis shows that six classes of graphs that can be represented by planar clique-star representations, and four classes of graphs that can be represented by planar reduced-clique-star representations. It also empirically shows that small graphs or either very sparse or very dense graphs maybe beneficially represented by planar clique-star or planar reduced-clique-star representations.
27

Displaying cliques in graph drawings

Yamamoto, Yosuke 19 September 2010 (has links)
Relational information represented by graphs can be found in various areas. Understanding completely connected groups of items is useful in studying relational information. However, when displayed in the form of a graph drawing, completely connected graphs contain quadratically many edges relative to the number of their vertices. This may increase the difficulty in identifying useful information, such as maximal cliques, in the graph. This thesis attempts to display the maximal cliques and the cliques contained in two or more maximal cliques in a given graph in an explicit and clear fashion. In order to achieve the goal, the thesis defines two models, the clique-star and the reduced-clique-star, that represent given input graphs. Both representations reduce the number of edges of the original graphs while maintaining the information about the maximal cliques. This thesis shows that six classes of graphs that can be represented by planar clique-star representations, and four classes of graphs that can be represented by planar reduced-clique-star representations. It also empirically shows that small graphs or either very sparse or very dense graphs maybe beneficially represented by planar clique-star or planar reduced-clique-star representations.
28

High power rotary microgenerator with multipole and multilayer planar microcoil

Wu, Tsung-Tien 01 July 2005 (has links)
MEMS process offers many advantages that the microsystem can be downscaled and can be combined with integrated circuit (IC). This technique has been successfully applied to micromotor, micropump, and microelectric apparatus but there has been existing problems of independent and compact power supply system. Hence this study presents an electromagnetic rotary microgenerator, mainly consisting of multilayer planar Cu microcoil and multipolar hard magnet of Nd/Fe/B by sintering. The layout of the microgenerator is 9 9 1 mm3 in volume. The paper also presents design and analysis of a multipolar rotary electromagnetic microgenerator. Theoretical mathematic model is derived to predict the power generation. Experimental results are compared with simulations. The experimental result shows good agreement with simulations. The preliminary experimental result reveals that this microgenerator with eight magnet poles and four-layer Cu planar microcoil generates an output voltage of 569 mV at 213.7 Hz frequency.
29

Investigating the Relationship Between Cilia and Planar Cell Polarity Signalling During Zebrafish Development

Borovina, Antonija 07 January 2014 (has links)
Cilia are microtubule-based organelles that project into the extracellular space and have various functions including transducing sensory information, regulating developmental signalling pathways, and generating directed fluid flow, making them important regulators of vertebrate development and homeostasis. Despite their importance, there are many aspects of cilia formation and function that remain poorly understood. The planar cell polarity (PCP) pathway is a branch of Wnt signalling that provides positional information to cells and is required for polarized morphogenic cell movements. Previous studies of PCP effector proteins suggested that PCP signalling was required for cilia formation. However, these proteins are not specific to the PCP pathway and are shared with other branches of Wnt signalling. To determine the role of a core and specific PCP regulator on ciliogenesis, I examined maternal-zygotic (MZ) vangl2 zebrafish mutants using an in vivo marker of cilia, Arl13b-GFP. Analysis of MZvangl2 mutants revealed that PCP is not required for cilia formation but is required for the posterior tilting and posterior positioning of motile cilia, essential for directed fluid flow. A parallel branch of studies suggested that cilia are actually required to regulate PCP signalling because defects in PCP-mediated morphogenic movements were observed with the knockdown of certain proteins that localize at or near cilia or basal bodies. To determine whether cilia were required to establish PCP, I generated MZ-intraflagellar transport-88 (IFT88) mutants, where ciliogenesis is completely abolished. Analysis of MZift88 mutants revealed that cilia are not directly required for PCP-mediated morphogenic movements. However, I observed that MZift88 mutants had defects in oriented cell divisions (OCD) occurring during gastrulation. Remarkably, these divisions occur prior to cilia formation, suggesting a cilia-independent role for IFT proteins in cell divisions, which may have important consequences on the interpretation of the role of cilia in disease.
30

Analysis of single and coupled microstrip-fed slot antennas

Akhavan, Haj Ghadir January 1996 (has links)
No description available.

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