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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.
1

Measuring availability of healthful foods in two rural Texas counties

Bustillos, Brenda Diane 15 May 2009 (has links)
A comprehensive in-store survey may capture the availability of healthful food alternatives in different store types in two rural counties. The purpose of this study was to: (1) compare the availability of healthful foods in two rural Texas counties; and (2) compare the variety of healthful foods in two rural Texas counties. This study also acts as a pilot test for further food availability research in four other rural counties of the Brazos Valley. An unobtrusive, observational survey was used to measure availability of healthful food in all (100%) grocery, convenience, and discount stores (n=44) in two rural counties in the Brazos Valley of Texas. Results from the surveys indicated that availability of healthful food alternatives varied greatly among the three different store types and two counties surveyed. Grocery stores (n=7) were more likely than convenience (n=31) and discount (n=6) stores to offer fresh fruits and vegetables, leanmeat options, and low-fat/skim milk products. Fresh fruits and vegetables were available in 100% of grocery stores. Only 16.1% of convenience stores, compared with 0.0% in discount stores, offered fresh fruits and vegetables. Variety of fruits and vegetables varied greatly among the three different store types and the two counties surveyed. Findings suggest that the survey utilized was feasible in determining the availability of healthful food items in two rural counties. Implications of this study include the need for knowledge and awareness of rural consumers and rural food supply. Furthermore, nutrition education for rural consumers and those purchasing foods provided to rural areas is desired. This study provided that further investigation into the availability of healthful foods in rural areas is needed.
2

An analysis of the impact of reliability and maintainability on the operating and support (O & S) costs and operational availability (Ao) of the RAH-66 Comanche Helicopter

Dellert, Gregg M. 12 1900 (has links)
S costs and Ao is significant if the predicted reliability goals are not met. / US Army (USA) author
3

Assessment of server location on system availability by computer simulation /

Weissmann, Eric. January 1994 (has links)
Report (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Includes bibliographical references (leaf 40). Also available via the Internet
4

An analysis of the impact of reliability and maintainability on the operating and support (O&S) costs and operational availability (Ao) of the RAH-66 Comanche Helicopter/

Dellert, Gregg M. January 2001 (has links) (PDF)
Thesis (M.S. in Management) Naval Postgraduate School, Dec. 2001. / "December 2001." Thesis advisor(s): Thom W. Crouch, Keebom Kang. Includes bibliographical references (p. 121-123). Also available online.
5

Parametric examination of the destruction of availability due to combustion for a range of conditions and fuels

Chavannavar, Praveen Shivshankar 01 November 2005 (has links)
A comprehensive second law analysis of combustion for a range of conditions and fuels was completed. Constant pressure, constant volume and constant temperature combustion processes were examined. The parameters studied were reactant temperature, reactant pressure, equivalence ratio and the fuels themselves. In addition, the contribution and relative significance of the various components (thermo-mechanical, reactive and diffusion) to the mixture availability was examined. Also, the effect of reactant mixture dissociation was incorporated into the combustion analysis. It was found that for similar initial conditions, constant pressure combustion and constant volume combustion exhibited similar trends. For constant temperature combustion, the trend is significantly different from the constant pressure and constant volume combustion, with almost the entire reactant availability being destroyed due to combustion at lower temperatures. Amongst the parameters examined, reactant mixture temperature had the most significant effect on the fraction of availability destroyed during combustion. The percentage availability destroyed reduced from 25 to 30% at 300 K to about 5% at 6000 K for constant pressure and constant volume combustion processes. The effect of the reactant mixture pressure on the fraction of availability destroyed was more modest. The values for the percentage availability destroyed for pressures ranging from 50 kPa to 5000 kPa were found to lie within a range of 5%. The effect of equivalence ratio on the fraction of reactant mixture availability destroyed was also documented. In general, it was found that the destruction of availability decreased with increasing equivalence ratios. This value, however, accounts for the availability due to fuel like species in the product mixture. Therefore, for practical applications, combustion of the stoichiometric mixture would be preferred over the rich equivalence ratios. It was found that the fraction of reactant availability destroyed increased with increasing complexity of the fuel??s molecular structure. In addition, it was shown that the diffusion availability terms is small and may be neglected, while the reactive availability and thermo-mechanical availability are more significant.
6

Database High Availability using SHADOW Systems

Pan, Xin January 2014 (has links)
Various High Availability DataBase systems (HADB) are used to provide high availability. Pairing an active database system with a standby system is one commonly used HADB techniques. The active system serves read/write workloads. One or more standby systems replicate the active and serve read-only workloads. Though widely used, this technique has some significant drawbacks: The active system becomes the bottleneck under heavy write workloads. Replicating changes synchronously from the active to the standbys further reduces the performance of the active system. Asynchronous replication, however, risk the loss of updates during failover. The shared-nothing architecture of active-standby systems is unnecessarily complex and cost inefficient. In this thesis we present SHADOW systems, a new technique for database high availability. In a SHADOW system, the responsibility for database replication is pushed from the database systems into a shared, reliable, storage system. The active and standby systems share access to a single logical copy of the database, which resides in shared storage. SHADOW introduces write offloading, which frees the active system from the need to update the persistent database, placing that responsibility on the underutilized standby system instead. By exploiting shared storage, SHADOW systems avoid the overhead of database-managed synchronized replication, while ensuring that no updates will be lost during a failover. We have implemented a SHADOW system using PostgreSQL, and we present the results of a performance evaluation that shows that the SHADOW system can outperform both traditional synchronous replication and standalone PostgreSQL systems.
7

Analysis of glucosinolates in oilseed rape

Wright, Alan January 1995 (has links)
Four methods of analysis for the determination of total and individual glucosinolates in Brassica napus cultivars (ie Gas Chromatography (GC), High Pressure Liquid Chromatography (HPLQ, Glucose Release, and X-ray Fluorescence Spectrometry (XRF)) were developed, refined, validated and applied. These were used to investigate both high and low glucosinolate cultivars of rapeseed (oilseed rape, Brassica napus), and reproducibility (between replicates) and repeatability (between analysis days) of these methods was assessed. From these studies, an indirect method of glucosinolate determination, involving X-Ray Fluorescence analysis, proved to give the least variable results. Furthermore, this was markedly more rapid than the other methods of analysis. Of the methods assessed for the determination of individual glucosinolates, High Pressure Liquid Chromatography (HPLC) gave less variable results than Gas Chromatography (the European Community (EC) recommended method for glucosinolate determination in oilseed rape at the time of study). Thus, BPLC and XRF analysis were selected as methods for subsequent glucosinolate analysis in the remainder of the study. Effects of geographicallo cation in relation to atmospherics ulphur depositiona nd plant sulphur uptake in Brassica napus cv Ariana grown throughout the UK were determinedin two consecutivey ears. An initial study comparedg lucosinolatele vels in rapeseed samples from 211 sites. A second more detailed study involved determinationo f foliar sulphurl evels (by XRF analysis)a t three stagesd uring plant developmenftr om selecteds itest hroughoutt he UK, and comparisono f thesew ith glucosinolate levels in the harvested seed from these sites. The results of these investigations proved comparable between years, with final glucosinolate levels generally corresponding to atmospheric sulphur deposition levels. Furthermore, high glucosinolatele vels in harvesteds eedg enerallyc orrespondewd ith high sulphur levelsi n foliage ast he plantse ntereds eed-podd evelopment.A series of controlled environment and glasshouse experiments were developed to investigate the effects of sulphur nutrition on glucosinolate development in rape plants during growth. These highlighted that glucosinolate levels in plant material could be manipulated with variation in supplied nutrients. Furthermore, plants initially propagated with sulphur-complete nutrient in hydroponic media, then transferred to sulphur-free nutrient mid-development, were found to give good seed yields with substantially lower glucosinolate levels. In conclusion, attention must be given to choosing the appropriate method for analysis of glucosinolates. Secondly, sulphur availability and sulphur status are critical factors in the determination of glucosinolatelevels, and the relationship between these factors merits further study
8

Stochastic characterization of a class of 2-state system availability processes

Chávez Fuentes, Jorge Richard 25 September 2017 (has links)
The system availability process indicates whether or not the interconnection of components is operating as intended at each time instant. It is shown that a 2-states system availability process that results from a transformation of a Markov chain is not a Markov chain. The probabilistic characterization of the system availability process is given.
9

Reliability Transform Method

Young, Robert Benjamin 22 July 2003 (has links)
Since the end of the cold war the United States is the single dominant naval power in the world. The emphasis of the last decade has been to reduce cost while maintaining this status. As the Navy's infrastructure decreases, so too does its ability to be an active participant in all aspects of ship operations and design. One way that the navy has achieved large savings is by using the Military Sealift Command to manage day to day operations of the Navy's auxiliary and underway replenishment ships. While these ships are an active part of the Navy's fighting force, they infrequently are put into harm's way. The natural progression in the design of these ships is to have them fully classified under current American Bureau of Shipping (ABS) rules, as they closely resemble commercial ships. The first new design to be fully classed under ABS is the T-AKE. The Navy and ABS consider the T-AKE program a trial to determine if a partnership between the two organizations can extend into the classification of all new naval ships. A major difficulty in this venture is how to translate the knowledge base which led to the development of current military specifications into rules that ABS can use for future ships. The specific task required by the Navy in this project is to predict the inherent availability of the new T-AKE class ship. To accomplish this task, the reliability of T-AKE equipment and machinery must be known. Under normal conditions reliability data would be obtained from past ships with similar mission, equipment and machinery. Due to the unique nature of the T-AKE acquisition, this is not possible. Because of the use of commercial off the shelf (COTS) equipment and machinery, military equipment and machinery reliability data can not be used directly to predict T-AKE availability. This problem is compounded by the fact that existing COTS equipment and machinery reliability data developed in commercial applications may not be applicable to a military application. A method for deriving reliability data for commercial equipment and machinery adapted or used in military applications is required. A Reliability Transform Method is developed that allows the interpolation of reliability data between commercial equipment and machinery operating in a commercial environment, commercial equipment and machinery operating in a military environment, and military equipment and machinery operating in a military environment. The reliability data for T-AKE is created using this Reliability Transform Method and the commercial reliability data. The reliability data is then used to calculate the inherent availability of T-AKE. / Master of Science
10

A reliability, maintainability, supportability and availability analysis of a submarine sonar system /

O'Keefe, John Daniel. January 1990 (has links)
Project report (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Includes bibliographical references (leaves 164-166). Also available via the Internet.

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