This thesis presents an analytical approach using Root-Loci method for designing optimum passive series RC snubbers for continuous-current synchronous buck switch mode power supply (SMPS). Synchronous buck SMPS is the most popular power converter topology found in modern consumer electronics. It offers relatively good efficiency to target the high-current and low-voltage requirements while it is also relatively inexpensive to implement. Passive series RC snubbers are simple, efficient and cost-effective open-loop equalizer circuit for synchronous buck SMPS. Its purpose is to control and to balance between the rate of rise and the overshoots of transient switching waveform in order to optimize efficiency and reliability Existing methods of RC snubber design are solely based on second-order approximation. It is investigated in this research that this approximation is highly inaccurate in SMPS applications because higher order equivalent models are required for the load path of the SMPS. The results using the RC snubbers obtained from existing method are shown to be unsatisfactory without correlation to the calculations and simulations based on second-order approximation. Optimum RC values obtained using Root-Loci approach presented in this thesis are shown to correlate to both Spice simulation and lab measurements.

Phytoremediation systems for petroleum hydrocarbons rely on a synergistic relationship between plants and their root-associated microbial communities. Plants exude organic compounds through their roots, which increase the density, diversity and activity of plant-associated microorganisms, which in turn degrade hydrocarbons. Understanding the mechanisms driving this relationship poses one of the more intriguing challenges in phytoremediation research. This study was designed to address that challenge. Plant-microbe interactions in a weathered-hydrocarbon contaminated soil were examined under controlled growth chamber, and field conditions. In both environments single-species grass treatments initially facilitated greater total petroleum hydrocarbon (TPH) degradation than <i> Medicago sativa </i> (alfalfa), mixed species, or control treatments. In growth chamber studies increased degradation was linked to increased aliphatic-hydrocarbon degrader populations within the rhizosphere. Under field conditions, specific recruitment of endophytic aliphatic-hydrocarbon degraders in response to high TPH levels may have facilitated increased degradation by the grass <i> Elymus angustus</i>(Altai wild rye, AWR). AWR stably maintained these communities during times of local drought, enabling them to act as subsequent source populations for rhizosphere communities. The broad phylogenetic diversity of AWR endophytes, compared to the <i> Pseudomonas</i>-dominated communities of other plants, contributed to the observed stability. The relative composition of exudates released by plants also impacted both degradation activity and potential. Alfalfa released higher concentrations of malonate, which hindered degradation by decreasing metabolic activity and concomitantly inhibiting catabolic plasmid transfer. In contrast, AWR exudates contained high levels of succinate, which was linked to increased catabolic gene expression and plasmid transfer. A reciprocal relationship between exudation patterns and endophytic community structure likely exists, and both parameters have a specific influence on rhizosphere degradation capacity. In this study, grasses were more successful in maintaining the specific balance of all parameters required for the transfer, preservation, and stimulation of hydrocarbon catabolic competency.

There are much economic and financial data which are restricted by some bounds, such as expenditure shares, unemployment, norminal interest rate, or target zone exchange rate. How to interpret and analyze time series whose behaviors can be well approximated by means of integrated processes, I(1), but are ¡§limited¡¨ in the sense that their range is constrained by fixed bounded is what this thesis develops. One method to analyze bounded variable of this paper is ¡§The Bounded Unit Root¡¨ which provided by Cavaliere (2005), and the other is using Gibbs sampling simulation and trying to recover the part of hidden variables. We would examin some empirical problems that has often been tackled in the literature and we give three time series which include Danish kron/Deutshe mark, Belgium Franc/ Deutshe mark, and Japan 1 mouth interbank interest rate for examples. We conclude that these three time series data are I(0) in classical unit root test framework, but are all I(1) in The Bounded Unit Root test framework. And the results of Gibbs sampling simulation are that Danish kron/Deutshe mark and Belgium Franc/ Deutshe mark are I(0), but Japan 1 mouth interbank interest rate is I(1).

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xi, 61 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 34-37).

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains viii, 51 p. : ill. Includes abstract. Includes bibliographical references (p. 39-42).

Revised; Originally Published: 2000 / 8 pp. / Whether you are beginning a new landscape or renovating an existing one, planning ahead can prevent many problems. The majority of maintenance requirements and plant problems result from either selecting the wrong kind of plant for a location or planting an inferior specimen of the selected plant type. In other words, there are two decisions to be made: ▪ What species, or kind, of tree are you going to buy — an oak, pine, mesquite, or acacia? ▪ Assuming you decide on an oak, which one in the row of oaks at the nursery are you going to buy? The first decision is called Plant Selection and the second is Selecting Plants. Our goal is to install the right plant in the right place. This publication will cover the factors involved in making good decisions to achieve this goal.

Revised 02/2015; Originally published: 2000. / The most important disease of woody dicotyledonous plants in Arizona is Phymatotrichopsis root rot (Cotton or Texas root rot) caused by a unique and widely distributed soil-borne fungus, Phymatotrichopsis omnivora. The fungus is indigenous to the alkaline, low-organic matter soils of the southwestern United States and central and northern Mexico.

Softwood cuttings of Euonymus alatus and the cultivar Rudy Haag, a nearly seedless cultivar, were taken in Kentucky on two cutting dates. E. alatus Rudy Haag cuttings taken in mid-May, untreated or treated with 1000 - 3000 ppm IBA, produced many roots on a high percentage of cuttings. Post-rooting shoot growth was reduced for the species with cuttings taken in June. Rudy Haag produced new growth on cuttings taken in May with no IBA treatment. Transplanting resulted in a decrease in new growth. Liner plants of E. alatus Compactus and Rudy Haag were planted into 1 and 3 gallon containers of two different types, conventional black plastic and root training. A second experiment exposed plants to two levels of supplemental fertilizer in addition to slow release. A subsample was sprayed with Fascination (BA + GA4+7) at 1500 ppm in late July. No difference was seen in above-ground growth due to container type or supplemental fertilizer. A change in root morphology is seen with root trainers. Three gallon containers produced a larger plant than one gallon containers. Rudy Haag sprayed with Fascination were greater in size and branch number than those not sprayed.

Plant growth and development depends on controlled cell expansion. This, in itself, is determined by the plant cell wall, a structural matrix of polysaccharides encasing the plant cell. One line of investigation that has proven particularly successful in elucidating the components of the plant cell wall machinery has been the forward genetic screens of cell wall mutants. In this study, the molecular and cellular characterisation of sloughy, a cell separation mutant in Arabidopsis thaliana, was commenced. This mutant has a striking phenotype, with files of elongating epidermal cells snaking away from the adjacent epidermal cells and from the underlying cortex, loosing contact from the side walls while remaining attached at the cell ends, in a manner reminiscent of border-like cells in the root cap of arabidopsis. The sloughy mutation was fine mapped to a short region on chromosome I using high resolution melt point analysis. On sequencing all five genes in this region, a single nucleotide mutation, introducing a stop codon, was detected in exon 2 in the previously-described heat shock transcription factor SCHIZORIZA that results in a truncated protein missing several conserved domains essential for activity. SCHIZORIZA acts as a cell fate determinate in the root meristem to promote cortex fate, while suppressing epidermal and root cap fate in the mature ground tissue. Although the literature on schizoriza mutants has focused on the developing root meristem, with little documentation on the cell separation phenotype further up in the roots, the investigation of a collection of schizoriza TILLING mutants revealed that aberrant cell separation was ubiquitous to schizoriza mutants with a severely truncated protein. To investigate cell identity in the mature roots, sloughy was crossed to GAL4-GFP enhancer trap lines that act as cell-specific markers. Epidermal identity lines revealed that sloughy possessed a supernumerary ground tissue layer with epidermal identity. A cortex and endodermal line revealed that these two identities are restricted to the endodermal layer and the next ground tissue layer out. There was no indication of root cap identity in the mature root with any of the root cap lines used, although partial lateral root cap identity has been previously described in the epidermal and subepidermal cell layers in the meristem of schizoriza mutants expressing SOMBRERO-GFP, a lateral root cap-specific transcription factor. Immunolabelling of cell wall epitopes revealed that the JIM13 antibody, which specifically labels arabinogalactan-proteins in wild-type root caps, often labelled the epidermal cells and surrounding mucilage further up the in the roots of sloughy. The aberrant cell separation present in sloughy is thought to be a consequence of epidermal cells possessing partial lateral root cap identity. The data on sloughy/schizoriza is sufficient to generate a model on how a meristem developmental gene can generate a cell separation phenotype in the mature roots. Loss of SCHIZORIZA causes confused cell identity in the root meristem that results in an epidermal and subepidermal layer possessing mixed epidermal and lateral root cap identity. The distinctive properties of border-like cells in the root cap of arabidopsis have been linked to unique cell wall maturation and developmental processes, implicating the cellulases CEL3 and CEL5, the pectin glycosyltransferase QUA1, the pectin methyltransferase QUA2 and other pectolytic enzymes. The ectopic expression of these cell wall enzymes in the epidermal and subepidermal layers of sloughy roots result in reduced adhesion along the sides of the cell, while the ends remain attached, causing the observed cell separation phenotype.

Thesis (M.S.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed Feb. 5, 2008). Includes bibliographical references (p. 71-79).