Forest managers concerned with maintaining soil productivity must consider the impacts of forestry practices upon the features of a site. One critical feature is the amount and type of organic matter on a site, which may affect soil development. This study addresses the question of whether CWD accumulations increase the intensity of podzolization, thus reducing the long-term productivity of a site.

Nuclear magnetic resonance (NMR) spectroscopy was used to determine the structure of transmembrane (TM) segment IX of the Na+/H+ exchanger isoform 1 (NHE1) in dodecylphosphocholine micelles. Studying isolated TM segments in this fashion constitutes a well-established "divide and conquer" approach to the study of membrane proteins, which are often extremely difficult to produce, purify, and reconstitute in full-length polytopic form. A similar approach was combined with NMR spin relaxation experiments to determine the peptide backbone flexibility of NHE1 TM VII. The combined NMR structural and dynamics studies are consistent with an important role for TM segment flexibility in the function of NHE1, a protein involved in apoptosis and myocardial disease. The study of the rhomboid protease system is also described from two perspectives: 1) I attempted to produce several TM constructs of the substrate spitz or a related construct and the production and purification are described in detail; and 2) I present coarse-grained molecular dynamics simulation results for the E. coli rhomboid ecGlpG and a spitz TM construct. Spitz appears to preferentially associate with rhomboid near TMs 1 and 3 rather than the proposed substrate gate at TM 5. The two proteins primarily interact at the termini of helices rather than within the hydrocarbon core of the bilayer. Finally, I present a detailed analysis of coarse-grained molecular dynamics simulations of the fibroblast growth factor receptor 3 TM domain dimerization. Specifically, algorithms are described for analyzing critical features of wild-type and G380R mutant constructs. The G380R mutation is the cause of achondroplasia, the most common form of human dwarfism. The results suggest that the proximity of a residue to the dimer interface may impact the severity of the mutant phenotype. Strikingly, heterodimer and mutant homodimer constructs exhibit a secondary dimer interface which may explain the increased signaling activity previously reported for the G380R mutation--the helices may rotate with the introduction of G380R. The unifying theme of this work is the 'study of membrane proteins' using complementary techniques from structural biology and computational biochemistry.

In this dissertation, Richardson extrapolation and other computational techniques are used to develop a series of high accuracy high efficiency solution techniques for solving partial differential equations (PDEs). A Richardson extrapolation-based sixth-order method with multiple coarse grid (MCG) updating strategy is developed for 2D and 3D steady-state equations on uniform grids. Richardson extrapolation is applied to explicitly obtain a sixth-order solution on the coarse grid from two fourth-order solutions with different related scale grids. The MCG updating strategy directly computes a sixth-order solution on the fine grid by using various combinations of multiple coarse grids. A multiscale multigrid (MSMG) method is used to solve the linear systems resulting from fourth-order compact (FOC) discretizations. Numerical investigations show that the proposed methods compute high accuracy solutions and have better computational efficiency and scalability than the existing Richardson extrapolation-based sixth order method with iterative operator based interpolation. Completed Richardson extrapolation is explored to compute sixth-order solutions on the entire fine grid. The correction between the fourth-order solution and the extrapolated sixth-order solution rather than the extrapolated sixth-order solution is involved in the interpolation process to compute sixth-order solutions for all fine grid points. The completed Richardson extrapolation does not involve significant computational cost, thus it can reach high accuracy and high efficiency goals at the same time. There are three different techniques worked with Richardson extrapolation for computing fine grid sixth-order solutions, which are the iterative operator based interpolation, the MCG updating strategy and the completed Richardson extrapolation. In order to compare the accuracy of these Richardson extrapolation-based sixth-order methods, truncation error analysis is conducted on solving a 2D Poisson equation. Numerical comparisons are also carried out to verify the theoretical analysis. Richardson extrapolation-based high accuracy high efficiency computation is extended to solve unsteady-state equations. A higher-order alternating direction implicit (ADI) method with completed Richardson extrapolation is developed for solving unsteady 2D convection-diffusion equations. The completed Richardson extrapolation is used to improve the accuracy of the solution obtained from a high-order ADI method in spatial and temporal domains simultaneously. Stability analysis is given to show the effects of Richardson extrapolation on stable numerical solutions from the underlying ADI method.

GPS is widely used for localization and tracking, however traditional GPS receivers consume too much energy for many applications. This thesis implements and evaluates the performance of a low energy GPS solution, including a working hardware prototype, that reduces energy consumption significantly. The prototype operates for 2 years on a coin cell battery, sampling every minute. The corresponding time for a traditional receiver is 2 days. The main difference is that a traditional receiver requires 30 seconds of data to estimate a position; this solution only requires 2 milliseconds of data, a reduction of a factor 15 000. The solution consists of a portable device, sampling the GPS signal, and server software that utilizes Doppler navigation and Coarse Time Navigation to estimate positions. The median positioning error is at most 38 meters in our tests. We expect that this solution will enable positioning for billions of devices in the near future.

The shear strength, elastic moduli and plastic strain characteristics of scaled-down ballast materials are investigated by use of the parallel gradation technique. Uniformly graded ballast materials chosen for the investigation are limestone, basalt and steel-slag. Steel-slag is a byproduct material of Eregli Iron and Steel Works, which is suitable to meet the durability test requirements as well as the electrical resistivity and the waste contaminants regulatory level. Conventional triaxial testing at a strain rate of 0.4 mm/min is used to obtain these characteristics for the scaled-down materials with a diameter of 100 mm specimen under a confining stress of 35 kPa, 70 kPa and 105 kPa / whereas that of only 35 kPa is used to characterize the accumulated plastic strain. The angle of internal friction, f, and the apparent cohesion, c, may be conservatively taken to be 42o and 35 kPa for all materials. The elastic moduli values for all materials may be predicted within an adequate estimate for the engineering purposes by using the power law parameters, K and n, determined for L-9.5 (D50 = 12.7 mm), the coarsest gradation tested for limestone. K with a reference pressure, pr = 1 kPa and n values for L-9.5, respectively, are 4365 and 0.636 for initial / 8511 and 0.419 for secant / 25704 and 0.430 for unloading-reloading elastic moduli. The unloading-reloading moduli increased, as the number of cycles increased. An increase in unloading-reloading modulus at N = 20 obtained was roughly 15% for scaled-down limestone / 10% for the basalt / and 5% for the steel-slag. The plastic strain after first cycle, &amp / #949 / 1, and the plastic strain coefficient, C can be represented as a function of mean particle size for each material type. For the limestone, basalt and steel-slag prototype size, D50 = 45 mm, &amp / #949 / 1 values of 0.59, 0.43 and 0.75 and C values of 0.54, 1.42 and 0.74 are predicted, respectively.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2007. / Thesis documentation sheet inserted. Includes appendix of four papers and manuscripts, three co-authored with others. Includes bibliographical references. Also issued electronically via World Wide Web in PDF format; online version lacks appendix.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: There is a need for a coarse-to-fine positioning system as per a case study presented by the project collaboration partner, the Technical University of Chemnitz. The case study involves the picking and placing of piezo-ceramic micro parts into milled micro cavities. The focus of the project is the creation and development of a systematic approach for the design and the implementation of a coarse-to-fine positioning system for micro material handling. A second focus is to determine the applicability of the system for highly accurate and repeatable micro drilling and micro-milling. A systematic approach entails combining innovation management (assists in overall project structure), systems engineering (assists in specific design steps and tools) and research questions. Micro-milling was achieved, however the system proved unsuitable for highly accurate and repeatable micro drilling. The coarse-to-fine positioning system was successfully designed, built, and tested for accurate micro material handling. / AFRIKAANSE OPSOMMING: Daar bestaan ’n behoefte aan ’n grof-tot-fyn-posisioneringstelsel - soos blyk uit die gevallestudie uiteengesit deur die samewerkende projekvennoot, die Tegniese Universiteit van Chemnitz. Die gevallestudie behels die uitsoek en plasing van piezo-keramiek partikels in gefreesde mikroholtes. Hierdie projek het gefokus op die skepping en ontwikkeling van ’n stelselmatige benadering tot die ontwerp en implementering van ’n grof-tot-fyn-posisioneringstelsel vir mikromateriaalhantering en mikromasjienering. ’n Stelselmatige benadering behels dat innovasiebestuur (hulp met die algehele projekstruktuur), stelselingenieurswese (hulp met spesifieke ontwerpstappe en -hulpmiddels) en navorsingsdoelwitte gekombineer word. Die geïmplementeerde stelsel is eksperimenteel getoets en daar is bevind dat dit aan die spesifikasies en vereistes voldoen.

O emprego de concreto com resistência à compressão ultrapassando 100 MPa e o aumento do número de aplicações do concreto de alto desempenho em diferentes regiões do país mostra que há espaço para a consolidação desta tecnologia no meio técnico nacional. Contudo na medida em que se eleva a resistência à compressão dos concretos, os agregados passam a exercer um papel cada vez mais importante no comportamento global do material. A busca constante pelo entendimento preciso da influência das características do agregado nas propriedades do concreto tem despertado o interesse de diversos trabalhos em todo o mundo. O objetivo deste trabalho foi estudar a influência da resistência à compressão da rocha e a influência da dimensão máxima característica do agregado graúdo, nas propriedades mecânicas de concretos no estado endurecido produzidos com diferentes consumos de água (200, 160, 145, 130 e 115 litros de água). Para a produção do concreto utilizou-se como referência os princípios estabelecidos no método de dosagem proposto por Mehta e Aïtcin (1990). A metodologia baseou-se em ensaios laboratoriais e no uso de ferramentas estatísticas para validação dos resultados. Com base nesses resultados obtidos foram propostos modelos de previsão de comportamento. Em termos de resistência à compressão observou-se que a influência da dimensão máxima característica é maior para concretos produzidos com consumo de água menor. Quanto à resistência do agregado, os resultados obtidos neste trabalho negam a teoria da resistência potencial do agregado. A resistência à tração mostrou-se somente influenciada pelo consumo de água. O módulo de elasticidade do concreto, no entanto foi diretamente influenciado pela resistência da rocha. / The use of concrete with compressive strength of 100 MPa and the number of applications of high performance concrete in different regions of Brazil shows that this technology seeks to consolidate the national technical means. But to the extent that amounts to the compressive strength of concrete, aggregates start to exert an increasingly important role in the global behavior of the material. The objective was to study the influence of the compressive strength of rock and the influence of maximum size of coarse aggregate characteristic, the mechanical properties of concrete in hardened produced with different water consumption (200, 160, 145, 130 and 115 liters of water). To produce the dosage of concrete was used as a reference the principles of the determination method proposed by Mehta and Aïtcin (1990). The methodology is based on laboratory tests and the use of statistical tools to validate the results. Based on these results were proposed prediction models of behavior. In terms of compressive strength was observed that the influence of the characteristic maximum dimension is greater for concretes with lower water consumption. As the aggregate’s resistance, the results obtained in this work deny the theory of the potential resistance. The tensile strength was found to be only influenced consumption of water. The modulus of elasticity of the concrete, however it was influenced by the strength of the aggregates.

abstract: Coarse Grain Reconfigurable Arrays (CGRAs) are promising accelerators capable of achieving high performance at low power consumption. While CGRAs can efficiently accelerate loop kernels, accelerating loops with control flow (loops with if-then-else structures) is quite challenging. Techniques that handle control flow execution in CGRAs generally use predication. Such techniques execute both branches of an if-then-else structure and select outcome of either branch to commit based on the result of the conditional. This results in poor utilization of CGRA s computational resources. Dual-issue scheme which is the state of the art technique for control flow fetches instructions from both paths of the branch and selects one to execute at runtime based on the result of the conditional. This technique has an overhead in instruction fetch bandwidth. In this thesis, to improve performance of control flow execution in CGRAs, I propose a solution in which the result of the conditional expression that decides the branch outcome is communicated to the instruction fetch unit to selectively issue instructions from the path taken by the branch at run time. Experimental results show that my solution can achieve 34.6% better performance and 52.1% improvement in energy efficiency on an average compared to state of the art dual issue scheme without imposing any overhead in instruction fetch bandwidth. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2014

abstract: Coarse-grained Reconfigurable Arrays (CGRAs) are promising accelerators capable of accelerating even non-parallel loops and loops with low trip-counts. One challenge in compiling for CGRAs is to manage both recurring and nonrecurring variables in the register file (RF) of the CGRA. Although prior works have managed recurring variables via rotating RF, they access the nonrecurring variables through either a global RF or from a constant memory. The former does not scale well, and the latter degrades the mapping quality. This work proposes a hardware-software codesign approach in order to manage all the variables in a local nonrotating RF. Hardware provides modulo addition based indexing mechanism to enable correct addressing of recurring variables in a nonrotating RF. The compiler determines the number of registers required for each recurring variable and configures the boundary between the registers used for recurring and nonrecurring variables. The compiler also pre-loads the read-only variables and constants into the local registers in the prologue of the schedule. Synthesis and place-and-route results of the previous and the proposed RF design show that proposed solution achieves 17% better cycle time. Experiments of mapping several important and performance-critical loops collected from MiBench show proposed approach improves performance (through better mapping) by 18%, compared to using constant memory. / Dissertation/Thesis / Masters Thesis Computer Science 2016