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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.
251

Analytical procedures for the determination of wattle polyphenols in wastewaters

Hendry, Antony John January 1984 (has links)
No description available.
252

High pressure liquid chromatographic quantification of nitrile biocatalysis

Mathiba, Kgama January 2012 (has links)
Nitrile biocatalysts are of use in the chemical and pharmaceutical industries for the synthesis of carboxyamides and carboxylic acids. In particular, the application of biocatalysts in the synthesis of single enantiomer compounds is of increasing interest, but requires novel substrate specific highly stereoselective biocatalysts. Addition to the limited toolbox of known nitrile biocatalysts requires definitive characterisation of the biocatalysts through accurate determination of the substrate profiles and quantification of activity. The accurate quantification of stereoisomers chiral mixtures to determine biocatalyst stereoselectivity remains a significant challenge due to the difficulty in separating stereoisomers by physical methods. The known nitrile metabolising organism, Rhodococcus rhodochrous ATCC BAA-870, was grown in a defined medium and harvested, providing whole cell biocatalyst. Additional biomass was disrupted to provide a cell free enzyme extract, which was put through an enzyme purification protocol to provide a solution with specific activity of 351 U.mg⁻¹. A portion of the enzyme was self immobilised using the SphereZyme™ technique. The nitrile hydratase SphereZymes™ (1.2 U.mg⁻¹ initial activity) that were prepared had pH and temperature optima of 6 and 30°C respectively, and could be recovered by repeated washing. The particles retained activity in the presence of the organic solvents isooctane and n-hexadecane saturated with 50 mM phosphate buffer (pH 7.5). An initial analytical system was devised for quantification of the nitrile hydratase activity using the non-chiral substrate benzonitrile. An improved reversed phase high performance liquid chromatography method was developed to separate and quantify benzamide, benzoic acid and benzonitrile. The mobile phase consisting of 0.1% trifluoroacetic acid in H₂O and acetonitrile (70:30, %v/v), at a flow rate of 0.5 ml.ml⁻¹, 25°C, resolved all three analytes in 3.5 minutes on a Waters X-Terra MS C18 3.5μm column. UV detection was carried out at 210 nm. Analytical methods to determine activity and enantioselectivity of the whole cell biocatalyst were subsequently developed for both β-amino nitriles and β-hydroxy nitrile substrates and hydrolysis products.
253

Building Reliable and Cost-Effective Storage Systems for High-Performance Computing Datacenters

Qiao, Zhi 08 1900 (has links)
In this dissertation, I first incorporate declustered redundant array of independent disks (RAID) technology in the existing system by maximizing the aggregated recovery I/O and accelerating post-failure remediation. Our analytical model affirms the accelerated data recovery stage significantly improves storage reliability. Then I present a proactive data protection framework that augments storage availability and reliability. It utilizes the failure prediction methods to efficiently rescue data on drives before failures occur, which significantly reduces the storage downtime and lowers the risk of nested failures. Finally, I investigate how an active storage system enables energy-efficient computing. I explore an emerging storage device named Ethernet drive to offload data-intensive workloads from the host to drives and process the data on drives. It not only minimizes data movement and power usage, but also enhances data availability and storage scalability. In summary, my dissertation research provides intelligence at the drive, storage node, and system levels to tackle the rising reliability challenge in modern HPC datacenters. The results indicate that this novel storage paradigm cost-effectively improves storage scalability, availability, and reliability.
254

Leveraging organisational energy to improve performance

Maxl, Pierre 23 February 2013 (has links)
The objective of this research was to gain insight into the key drivers of productive organisational energy and to determine whether there is a relationship between productive organisational energy and high performance in organisations. This study also aimed to identify key measures of success of organisations. Organisational energy has a critical role to play in driving both people behaviour and innovation in organisations, ultimately providing a competitive advantage.Both a quantitative and qualitative analysis was conducted on the data collected from four case study organisations, comprising a total sample size of 47 respondents. The research consisted of three phases. Phase One, which made use of an open-ended qualitative survey, was directed at industry experts who were required to identify and recommend four small- to medium- sized high-energy information technology organisations to be considered for this research. Phase Two consisted of gaining approval to conduct research within four of the recommended case study organisations, and conducting an open-ended exploratory face-to-face interview with each Managing Director, with the objective of determining the success, energy state, key drivers, and performance measures of the organisations, as well as the factors that drive the energy of staff. Furthermore, each Managing Director completed the same self-administered questionnaire that formed the basis of Phase Three. This structured survey was used to gather the perceptions and opinions of each organisation’s staff members in determining: the energy state of the organisation, the key drivers of organisational energy, and the link between organisation energy and performance. Statistical analysis techniques were used to determine whether significant relationships exist between the drivers of organisational energy and their respective rankings; and between organisational energy and organisational performance.The study provided evidence that intrapreneurial orientation, collective identity, employee investment and leadership are the most significant drivers of productive organisational energy and confirmed the existence of a significant relationship between productive organisational energy and high performance organisations. Through this research, a model has been developed that can be utilised by leaders of organisations to leverage organisational energy in order to improve and measure organisational performance, thereby creating a sustainable competitive advantage. / Dissertation (MBA)--University of Pretoria, 2012. / Gordon Institute of Business Science (GIBS) / unrestricted
255

Vývoj HPLC metody pro hodnocení čistoty a stability fesoterodinu za použití přístupu plánování experimentu / Development of HPLC method for evaluating the purity and stability of fesoterodine using a design of experiment approach

Erdeová, Karolína January 2017 (has links)
The aim of this diploma thesis was to develop and validate a high performance liquid chromatography (HPLC) method for purity and stability evaluation of fesoterodine. The HPLC method development was carried out using design of experiments (DOE), which allows to find optimal separation conditions within small number of experimental analysis. Design was done by using L18 linear model. Chromatographic system of the developed method consisted of a C8 stationary phase (SF) XBridge BEH - C8 (100 x 4.6 mm, 2.5 µm), a binary mobile phase (MF) consisting of 10mM borate buffer pH 9.2 and MeOH in various ratios according to the gradient program. Flow rate was 0.7 ml/min, column temperature 35 řC and a diode-array detector (DAD) was applied for the detection at 227 nm. Analysis time was 22 min. The optimized method was validated and the forced degradation study was performed. Studied effects were: the effect of elevated temperature (60 řC), humidity (10 and 75% relative humidity), acidic and basic conditions, oxidation and light. Peak purity of fesoterodine was evaluated for all experiments of forced degradation study. Additionally, the sensitivity of the active substance to hydrolysis was determined within the pH range of 2-10.
256

SORPTIVITY, RESISTIVITY AND POROSITY OF CONCRETE CONTAINING SUPPLEMENTARY CEMENTITIOUS MATERIALS

Unknown Date (has links)
Supplementary cementitious materials (SCMs), are beneficial when used as partial replacement of cement in concrete mixtures for coastal concrete structures, blended with Portland cement (binary or ternary mixes), i.e., high-performance concrete provides improved properties when exposed to marine harsh environment. In order to characterize selected durability properties of different concrete mixtures, a testing program was established. The intent of this study consists of testing 10cm diameter x 20cm long concrete specimens prepared with a range of different mix designs. 1) to evaluate the rate of water absorption due to capillary suction, referred to as sorptivity, 2) to evaluate the concrete surface resistivity, 3) to evaluate and compare the total porosity of specimens with different mixes, and 4) to obtain correlations between resistivity and sorptivity. All of these experimental tests were carried out according to ASTM International Standards (Sorptivity, Porosity) and Florida Method of Test (Resistivity). The tests were performed on concrete samples at various ages. Moreover, The results provided a fast and reasonable approximation of the concrete durability over time. Ordinary portland cement was partially replaced with supplementary cementitious materials including: fly ash (20%), silica fume (8%) and blast furnace slag (50%). These SCMs are highly effective in creating more durable concrete design mixtures. The water-to-cementitious (w/cm) ratios of 0.41 and 0.35 were investigated. The concrete that contains pozzolanic materials has demonstrated progress in extending the time for initiation of corrosion. The test results obtained indicate that the concurrent inclusion of fly ash and silica fume greatly reduced water penetration. The mixes containing slag also showed lower porosity and water absorption result, when compared to specimens containing fly ash only. Ternary concrete mixtures specimens showed much higher surface resistivity values than binary mixture specimens. These results suggest that reducing w/cm ratio, adding SCMs to concrete mixtures improved the concrete durability. The possibilities for the risks of corrosion initiation would be minimized (delayed) by prescriptive and then performance-based concrete blends with SCM materials optimized for service exposure in aggressive environments. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection
257

Troubleshooting a Nonresponder: Guidance for the Strength and Conditioning Coach

Gleason, Benjamin H., Hornsby, William G., Suarez, Dylan G., Nein, Matthew A., Stone, Michael H. 01 June 2021 (has links)
Ideally an athlete would continue to improve performance indefinitely over time, however improvement slows as the athlete approaches their genetic limits. Measuring performance is complex—performance may be temporarily depressed following aggressive training for multiple reasons, physiological and psychosocial. This reality may be vexing to the strength and conditioning coach, who, as a service provider, must answer to sport coaches about an athlete’s progress. Re-cently an evaluation mechanism for strength and conditioning coaches was proposed, in part to help coaches establish their effectiveness within the organization. Without formal guidance and realistic expectations, if an athlete is not bigger, leaner, stronger, etc. as a result of training within a specified timeframe, blame is often placed upon the strength and conditioning coach. The purpose of this article is to explore possible causes of what may be perceived as athlete non-responses to training and to provide guidance for the coach on how to handle those issues within their domain. A process of investigation is recommended, along with resources to assist coaches as they consider a broad range of issues, including enhancing existing testing methods, improving athlete behaviors, and adjusting processes designed to bring about performance improvement.
258

Pharmacokinetics and Bioavailability of Moxifloxacin in Calves Following Different Routes of Administrations

Goudah, A., Hasabelnaby, S. 01 April 2010 (has links)
Background: Moxifloxacin is a new fourth-generation 8-methoxy fluoroquinolone developed primarily for the treatment of community-acquired pneumonia and upper respiratory tract infections. The aim of the study was to investigate the plasma pharmacokinetics characteristic of moxifloxacin in calves, after intravenous, intramuscular and subcutaneous administration of a single dose. Meanwhile, plasma protein binding and bioavailability of moxifloxacin were also estimated. Methods: Plasma concentrations of moxifloxacin were measured using a modified HPLC method, and the extent of plasma protein binding was determined in vitro using ultrafiltration. Results: Following intravenous administration, the half life of elimination, the volume of distribution at steady state and the area under the curve were 3.29 h, 0.94 l/kg and 24.72 μg·h/ml, respectively. After intramuscular and subcutaneous administration of moxifloxacin at the same dose, the peak plasma concentrations were 2.41 and 2.20 μg/ml and were obtained at 1.54 and 1.59 h, respectively. The systemic bioavailabilities were 87.19 and 75.94%, respectively. The in vitro plasma protein binding of moxifloxacin in plasma of calves was 27%. Conclusion: A high peak plasma concentration, area under the curve, rapid absorption and bioavailability following intramuscular and subcutaneous administration characterize the pharmacokinetics of moxifloxacin in calves.
259

Application-aware resource management for datacenters / Applikationsmedveten resurshantering för datacenter

Souza, Abel Pinto Coelho de January 2018 (has links)
High Performance Computing (HPC) and Cloud Computing datacenters are extensively used to steer and solve complex problems in science, engineering, and business, such as calculating correlations and making predictions. Already in a single datacenter server, there are thousands of hardware and software metrics – Key Performance Indicators (KPIs) – that individually and aggregated can give insight in the performance, robustness, and efficiency of the datacenter and the provisioned applications. At the datacenter level, the number of KPIs is even higher. The fast growing interest on datacenter management from both public and industry together with the rapid expansion in scale and complexity of datacenter resources and the services being provided on them have made monitoring, profiling, controlling, and provisioning compute resources dynamically at runtime into a challenging and complex task. Commonly, correlations of application KPIs, like response time and throughput, with resource capacities show that runtime systems (e.g., containers or virtual machines) that are used to provision these applications do not utilize available resources efficiently. This reduces datacenter efficiency, which in term results in higher operational costs and longer waiting times for results. The goal of this thesis is to develop tools and autonomic techniques for improving datacenter operations, management and utilization, while improving and/or minimizing impacts on applications performance. To this end, we make use of application resource descriptors to create a library that dynamically adjusts the amount of resources used, enabling elasticity for scientific workflows in HPC datacenters. For mission critical applications, high availability is of great concern since these services must be kept running even in the event of system failures. By modeling and correlating specific resource counters, like CPU, memory and network utilization, with the number of runtime synchronizations, we present adaptive mechanisms to dynamically select which fault tolerant mechanism to use. Likewise, for scientific applications we propose a hybrid extensible architecture for dual-level scheduling of data intensive jobs in HPC infrastructures, allowing operational simplification, on-boarding of new types of applications and achieving greater job throughput with higher overall datacenter efficiency.
260

Computation of a Damping Matrix for Finite Element Model Updating

Pilkey, Deborah F. 26 April 1998 (has links)
The characterization of damping is important in making accurate predictions of both the true response and the frequency response of any device or structure dominated by energy dissipation. The process of modeling damping matrices and experimental verification of those is challenging because damping can not be determined via static tests as can mass and stiffness. Furthermore, damping is more difficult to determine from dynamic measurements than natural frequency. However, damping is extremely important in formulating predictive models of structures. In addition, damping matrix identification may be useful in diagnostics or health monitoring of structures. The objective of this work is to find a robust, practical procedure to identify damping matrices. All aspects of the damping identification procedure are investigated. The procedures for damping identification presented herein are based on prior knowledge of the finite element or analytical mass matrices and measured eigendata. Alternately, a procedure is based on knowledge of the mass and stiffness matrices and the eigendata. With this in mind, an exploration into model reduction and updating is needed to make the problem more complete for practical applications. Additionally, high performance computing is used as a tool to deal with large problems. High Performance Fortran is exploited for this purpose. Finally, several examples, including one experimental example are used to illustrate the use of these new damping matrix identification algorithms and to explore their robustness. / Ph. D.

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