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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.
341

A Study in Sorghum Bicolor: QTL Analysis of Photoperiod Sensitive Sorghums, Evaluation of Sorghum x Sugarcane Hybrids and Trait Introgression for Intergeneric Hybrid Improvement

Bartek, Matthew 16 December 2013 (has links)
Recently designated as a bioenergy crop, Sorghum is rather unique as it can produce large quantities of cellulose or sugar which can be used to produce advanced biofuels or compounds. Sweet sorghum contains high levels of sugars and biomass sorghums consist primarily of ligno-cellulosic biomass. Improvement of both sorghum types is essential for maximizing production and conversion efficiency. Photoperiod sensitive sorghum is thought to maximize biomass production yet maturity influence on biomass production and composition is not fully understood. Utilizing sorghum for sugar production has increased efforts to develop sweet sorghums with sugar yields similar to sugarcane. Hybridization of these species has been investigated with, until recently, little success. Testing newly developed intergeneric hybrids and improvement of parents used in their creation will determine their feasibility and improve hybrid performance. Objectives of this research are multifaceted. First, analyze photoperiod sensitive sorghum in varying day length environments to determine maturity effects on plant phenotype, composition, and QTL detection. Second, analyze intergeneric sorghum × sugarcane hybrids to determine agronomic performance in relation to sugarcane. Lastly, introgress the iap allele into sweet sorghum females for use in intergeneric hybrid creation. Photoperiod sensitive sorghum RILs were evaluated in College Station and Weslaco, Texas and Puerto Rico which caused differential expression of plant maturity. Genetic control of trait expression was high for each location. Results indicate gradual induction of plant maturity increases detection of phenotypic QTL and detection of compositional QTL increases when maturity effects on plant phenotype are reduced. Intergeneric sorghum × sugarcane F_1 hybrids were compared to sugarcane in Weslaco, Texas in 2011. Each hybrid expressed agronomic traits similar or better than that of the sugarcane variety. High levels of repeatability and genetic influence on trait expression were observed. Overall performance of the sugarcane variety was better than any individual hybrid tested. Introgression of iap into sweet sorghum was successful and generated seventeen new sweet sorghum female genotypes possessing the allele. Only two genotypes exhibited higher brix readings and both were later maturing than Tx3361. Height and maturity of all developed genotypes varied and desirability of developed lines was similar to Tx3361.
342

Obtaining a quality model for manufacturing systems and establishing a maintenance-quality link

El Gheriani, Hany 25 June 2008 (has links)
This thesis describes the application of the stochastic-flow-modeling (SFM) approach to represent the quality behavior of a manufacturing system. Initially, a simple, one-product type SFM is discussed and then a more complex multiple-product manufacturing system is developed. This quality SFM-based model has aggregation by station, product, and operational shift. Subsequently, potential supervisory control architectures that could be used in conjunction with this quality-based SFM are discussed and developed. Distribution parameter fitting is explored using static and adaptive approaches and a comparison between these two approaches is given. Then, the accuracy of the SFM modeling technique is demonstrated using two simulation examples. Effective equipment maintenance is essential for a manufacturing plant seeking to produce high quality products. The impact of equipment reliability and quality on throughput have been well established, but the relationship between maintenance and quality is not always clear nor direct. Therefore, after developing a SFM to represent the quality of a manufacturing system, the focus of this work shifts towards identifying correlations between maintenance and quality. This thesis describes a statistical modeling method that makes use of a Kalman filter to identify correlations between independent sets of maintenance and quality data. With such a method, maintenance efforts can be better prioritized to satisfy both production and quality requirements. In addition, this method is used to compare results from the theoretical maintenance-quality model to data from an actual manufacturing system. Results of the analysis indicate the potential for this method to be applied to preventive, as well as reactive maintenance decisions, since ageing aspects of equipment are also considered in the model. / Thesis (Master, Chemical Engineering) -- Queen's University, 2008-06-25 11:18:16.925
343

Field Physiology and Growth of Select Poplar Clones

Ayton, Kelsey L Unknown Date
No description available.
344

Synthesis and interfacial characterization of metal-semiconductor contacts by galvanic displacement

Nagy, Sayed Unknown Date
No description available.
345

Response of leafy reduced-stature maize (Zea mays L.) hybrids to plant population densities and planting patterns in a short-season area

Begna, Sultan Hussein. January 1996 (has links)
The yield of short-season hybrids is lower than long-season hybrids, mainly as a result of the low final leaf area developed by the short-season plants. This is due to the smaller plant stature and smaller leaf number and size of short-season adapted hybrids. In addition, in short-season areas the thermal-time available may be insufficient to mature grain of current maize hybrids. Maize hybrids which accumulate leaf area quickly, mature earlier, yield well and tolerate higher population densities better than the currently available hybrids would be more suitable for production in short-season areas. The "Leafy reduced-stature" maize hybrids, which have only recently been developed, have traits which address these criteria. There has been no previous effort to evaluate the effects of more than two plant population densities or the effects of planting patterns on the yield, yield components and vegetative growth of these hybrids. in 1995, field experiments were conducted at two sites near Montreal to compare the response of leafy reduced-stature (LRS), non-leafy normal stature (NLNS), and non-leafy reduced-stature (NLRS) maize hybrids to plant population densities and planting patterns. LRS maize hybrids showed the most rapid growth of the first ear, and the highest yield per single plant and per hectare at high plant population densities in paired rows. LRS hybrids also had longer grain filling periods, lower grain moisture contents and higher harvest indices than conventional (NLNS) hybrids. Rapid growth of the first ear and a higher harvest index are indications that LRS hybrids should be more tolerant of higher population densities than currently available hybrids. Therefore, LRS hybrids show promise for production in short-season areas at high plant population densities where maize cultivation is not currently economical due to shortness of the growing-season.
346

On stabilization and control of hybrid systems

Ezzine, Jelel 05 1900 (has links)
No description available.
347

Optimization of the fuel consumption of a parallel hybrid electric vehicle

Khan, Bruno Shakou 05 1900 (has links)
No description available.
348

Mate Choice, Genetic Variation, and Population Structure in Hybrid Zones

Culumber, Zachary Wyatt 2011 December 1900 (has links)
Natural hybrid zones provide opportunities to study a range of evolutionary phenomena from speciation to the genetic basis of fitness-related traits. Additionally, investing the structure of hybrid zones can provide valuable insight in the ecology and evolution of species. The present dissertation approaches the investigation of natural hybrid zones between Xiphophorus birchmanni and X. malinche from a population genetics perspective. The goal of the chapters herein are to investigate the genetic structure of these natural hybrid zones overall and the genetic structure of the populations within them in an effort to better understand the factors producing and maintaining spatial genetic patterns among this species pair and their hybrids. Using informative single nucleotide polymorphisms (SNPs) in one mitochondrial and three nuclear intron loci, I show that hybrid zones occur in replicated fashion in multiple stream reaches along a gradient from high to low elevation. Tests of FIS and linkage disequilibrium (LD) revealed significant genetic structure within a small subset of populations. Specifically, parentals and hybrids all three occur in some locations while other locations appear to be hybrid swarms. I then investigated a behavioral mechanism of reproductive isolation - social association, which might affect population structure. In clean water, individuals shoaled significantly more closely with conspecifics. Additionally, genotyping of females and their embryos revealed signatures of non-random mating in structured populations. Taken together, assortative social grouping, which may translate to assortative female mate choice, likely plays a role in maintaining population structure. Finally, I show that fluctuating asymmetry is significantly higher in unstructured than structure populations. This is a further indication that some form of non-random mating occurs in structured populations and has effects on male phenotypes.
349

HYBRID FLOW STRATEGIES FOR HIGH VARIETY LOW VOLUME MANUFACTURING FACILITIES TO IMPLEMENT FLOW AND PULL

Narayanan, Mukund 01 January 2002 (has links)
Lean Manufacturing has proven to be a very successful strategy for achieving production efficiencies. The basic elements of lean manufacturing are flow and pull. The traditional methods for establishing flow and pull do not fit well in the realm of high variety low volume manufacturing systems. This thesis provides a general framework for establishing flow and pull in high variety low volume manufacturing systems, through the concept of hybrid flow layouts. The existing analytical procedure for forming hybrid flow layouts is described and a new heuristic procedure, that overcomes some of the limitations of the existing procedure, is proposed. The performance of the new procedure in comparison to the existing procedure is illustrated using a real world case study. Finally, certain practical implementation issues that affect the formation of hybrid flow layouts are provided.
350

Experiential Learning with Respect to Model Based Design Applied to Advanced Vehicle Development

Singh, Gurhari January 2014 (has links)
With the need for greener powertrains every more present, automakers and part suppliers are lacking skill staff to fulfill design roles. It is estimated there are over 20 million lines of software code in vehicles today and many embedded controllers. The shortage of these engineers is compounded by the economic down-turn of 2008-2009, which resulted in massive 20% to 30% layoffs, reduced internships and reduction of programs designed to recruit new talent. To increase their workforce pool, automakers are working with universities and governments operate student competitions such as EcoCAR 2: Plugging into the Future, alongside traditional private/university collaborations. These programs present students with real-world engineering challenges and the opportunities to design/construction solutions. This also exposes students to the concepts of experiential learning. The objective of this thesis will be to discuss the design, construction and operation of a vehicle for a student design competition or research group at an educational institution. A process based on model based design will be undertaken, which allows for a majority of the vehicle???s design to be completed virtually prior to vehicle prototyping. In this work the model based design method is based on General Motor???s Vehicle Design Process. A project management plan is also proposed, which breaks down tasks into three technical areas (mechanical, electrical and controls) and allows for parallelization and reduced development time will also be proposed. Finally, the resources required to operate a vehicle design team will be defined. This includes the support needed from the University, physical space, software and hardware tools, safety considerations and human capital. Examples are drawn from 2013 Chevrolet Malibu converted to a plug-in hybrid vehicle with an ethanol engine and a battery pack was designed and built. This thesis will showcase the concepts mentioned above through examples from the University of Waterloo Alternative Fuels Team and its participation in international EcoCAR 2 vehicle development competition. The conclusion is that application of the concepts did result in the successful construction of an EcoCAR 2 vehicle. Generally projects that were successful were provided with sufficient technical information from suppliers and supported with past-experiences. Recommendations include: (i) working with suppliers who are familiar with academic environments (including working with students new to vehicle design), (ii) rigorous documentation of design for future designs; and (iii) close collaboration with industry experts to review designs, manufacturing, project management and budgets.

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