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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.
201

Analytical applications of the peroxyoxalate chemiluminescence reaction

Sanders, Matthew Graham January 1999 (has links)
The overall objectives of this thesis were to investigate the potential of the peroxyoxalate chemiluminescence (POOL) reaction for the quantitative detection of target analytes in non-aqueous matrices and to compare quantitative performance with fluorescence detection. The target analytes investigated were polycyclic aromatic hydrocarbons (PAHs) and aliphatic amines. These were selected as an important class of compounds in engine exhaust emissions and a detergent additive in diesel fuel respectively. Chapter one outlines the challenges of analysing petroleum products and engine exhaust emissions and discusses the potential of luminescence techniques, particularly chemiluminescence (CL), for the quantification of trace components. The chapter also reviews the technique of flow injection (FT) as a means of sample delivery for CL detection and as a potential technique for field deployment. Liquid chromatography techniques are described as a means of separation of complex matrices, e.g. fuels and engine exhaust particulates, in the laboratory prior to CL detection. The luminescence properties of several PAHs were investigated in Chapter Two. Optimum excitation and emission wavelengths for eleven PAHs in four different solvents were determined using a batch fluorescence technique. A FI approach was used to determine PAH concentrations using fluorescence and POCL detection. Two aryl oxalates; bis(2,4-dinitophenyl)oxalate and bis(2,4,6-trichlorophenyl)oxalate were compared for their suitability for PAH determinations and an investigation of the key variables (e.g. concentration of aryl oxalate and hydrogen peroxide, mobile phase composition and pH) affecting POCL was performed. Recommendations for the optimum conditions for the determination of PAHs by POCL detection were determined, A comparison between a photodiode based detection device and a low power (12V) photomultiplier tube was also described. In Chapter Three the procedure of using POCL detection as a post column liquid chromatography (LC) detector for PAHs has been considered. The performance of the POCL detection system was compared with wavelength programmed fluorescence. Both reversed and normal phase LC was investigated and the suitability of POCL detection with each approach was discussed. Additionally the procedure for the LC separation and analysis of SRM 1649 (Urban Dust/Organics) and SRM 1650 (Diesel Particulate Matter) was described. The relative performance of fluorescence and CL detection are discussed. Chapter four describes the principles of multivariate calibration of spectrophotometric data, and three commonly applied techniques (PCR, PLSI and PLS2). Fluorescence data was obtained for synthetic mixtures of PAHs containing two, three, four and five components. A procedure whereby individual spectra were 'glued' together before undergoing data analysis has been developed and the results obtained discussed. POCL emission spectra for five PAHs were acquired using a two-dimensional charge coupled device (CCD). The sensitivity of the CCD system toward POCL detection of PAHs and a multivariate investigation using benzo[a]pyrene and benzo[k]fluoranthene has been described. The potential of the fluorescence and CL approaches used has been discussed. Chapter five describes the aryl oxalate sulphorhodamine-101 CL reaction and its application to the determination of amines. A FI optimisation of the reaction parameters is presented together with some quantitative data for the detection of a homologous series of amines and dodecylamine (a commonly added detergent compound in diesel fuels). The application of the technique toward the detection of dodecylamine in a diesel fuel matrix and the potential as a field deployable technique was also considered.
202

The chemical and physical analyses of new and degraded lubricating oils

Singleton, Nichola Louise January 1993 (has links)
No description available.
203

Unsteady gas flow in the manifolds of multicylinder automotive engines

Bingham, J. F. January 1983 (has links)
No description available.
204

Inlet manifold fuel film study

Creery, Niall James January 2000 (has links)
No description available.
205

Design and Development of a Direct-acting Piezoelectric Fuel Injector

Nouraei, Hirmand 26 November 2012 (has links)
Manufacturers face the challenge of enhancing fuel efficiency, engine performance, and reducing harmful emissions. Novel fuel injection technologies can assist in meeting such demands. This dissertation summarizes the stages in the design, prototyping and experimental analysis of a direct-acting piezoelectric fuel injector concept. In the proposed design, a piezoelectric stack actuator is used to directly control the injection of fuel in order to enhance the injection characteristics by utilizing the fast response time of the actuator. The direct-acting concept was implemented by developing a motion inverter in the form of a disc that reverses the direction of the input and allows the actuator to directly control injections. Tests with input signals similar to those used in diesel engines confirmed the theoretical calculations and verified the prototype’s performance. This design can control the quantity of injected fuel more precisely than currently available commercial injectors.
206

Novelty and Diversity in Retrieval Evaluation

Kolla, Maheedhar 21 December 2012 (has links)
Queries submitted to search engines rarely provide a complete and precise description of a user's information need. Most queries are ambiguous to some extent, having multiple interpretations. For example, the seemingly unambiguous query ``tennis lessons'' might be submitted by a user interested in attending classes in her neighborhood, seeking lessons for her child, looking for online videos lessons, or planning to start a business teaching tennis. Search engines face the challenging task of satisfying different groups of users having diverse information needs associated with a given query. One solution is to optimize ranking functions to satisfy diverse sets of information needs. Unfortunately, existing evaluation frameworks do not support such optimization. Instead, ranking functions are rewarded for satisfying the most likely intent associated with a given query. In this thesis, we propose a framework and associated evaluation metrics that are capable of optimizing ranking functions to satisfy diverse information needs. Our proposed measures explicitly reward those ranking functions capable of presenting the user with information that is novel with respect to previously viewed documents. Our measures reflects quality of a ranking function by taking into account its ability to satisfy diverse users submitting a query. Moreover, the task of identifying and establishing test frameworks to compare ranking functions on a web-scale can be tedious. One reason for this problem is the dynamic nature of the web, where documents are constantly added and updated, making it necessary for search engine developers to seek additional human assessments. Along with issues of novelty and diversity, we explore one approximate approach to compare different ranking functions by overcoming the problem of lacking complete human assessments. We demonstrate that our approach is capable of accurately sorting ranking functions based on their capability of satisfying diverse users, even in the face of incomplete human assessments.
207

Thermodynamic And Structural Design And Analysis Of A Novel Turbo Rotary Engine

Ercan, Taylan 01 September 2005 (has links) (PDF)
A novel turbo rotary engine, operating according to a novel thermodynamic cycle, having an efficient compression phase, a limited temperature combustion phase followed by a long power extraction phase is designed. Thermodynamic and structural design and analysis of this novel engine is carried out and two prototypes are manufactured according to these analysis. High performance figures such as torque, power and low specific fuel consumption are calculated. Also the component tests of the manufactured prototypes are completed and their results are demonstrated.
208

A quasi-dimensional spark ignition two stroke engine model

Lewis, Daniel January 2014 (has links)
Despite challenges with poor emissions and fuel economy, gasoline two stroke engines continue to be developed for a number of applications. The primary reasons for the choice of a gasoline two stroke engine includes its low cost, mechanical simplicity and high specific power output. Some applications for the gasoline two stroke engine include small capacity motorcycles and scooters, off road recreational vehicles, hand held power tools and unmanned aerial vehicles. New technologies, which are already mature in four stroke engines, are now being applied to two stroke engines. Such technologies include direct fuel injection, electronic engine management and exhaust gas after treatment. To implement these new technologies computation models are being continuously developed to improve the design process of engines. Multi-dimensional computational fluid dynamics modelling is now commonly applied to engine research and development, it is a powerful tool that can give great insight into the thermofluid working of an engine. Multi-dimensional tools are however computationally expensive and quasi-dimensional modelling methods are often better suited for the analysis of an engine, for example in transient engine simulation. This thesis reports the development of a new quasi-dimensional combustion model for a loop scavenged two stroke engine. The model differs from other quasi-dimensional models available in the literature as it accounts for a bulk motion of the flame front due to the tumble motion created by the loop scavenge process. In this study the tumble motion is modelled as an ellipsoid vortex and the size of the vortex is defined by the combustion chamber height and a limiting elliptical aspect ratio. The limiting aspect ratio has been observed in experimental square piston compression machines and optical engines. The new model also accounts for a wrinkled flame brush thickness and its effects on the interaction between flame front and combustion chamber. The new combustion model has been validated against experimental engine tests in which the flame front propagation was measured using ionization probes. The probes were able determine the flame front shape, the bulk movement of the flame front due to tumble and also the wrinkled flame brush thickness.
209

The mixing characteristics of dilution jets issuing into a confined cross-flow

Carrotte, Jonathan F. January 1990 (has links)
An experimental investigation has been carried out into the mixing of a row of jets injected into a confined cross-flow. Measurements were made on a fully annular test facility, the geometry of the rig simulating that found in the dilution zone of a gas turbine combustion chamber. A small temperature difference of 44°C between the cross-flow and dilution fluid allowed the mixing characteristics to be assessed, with hot jets being injected into a relatively cold cross-flow at a jet to cross-flow momentum flux ratio of 4.0. The investigation concentrated on differences in the mixing of individual dilution jets, as indicated by the regularity of the temperature patterns around the cross-flow annulus. Despite the uniform conditions approaching the dilution holes there were significant differences in the temperature patterns produced by the dilution jets around the annulus.
210

Machinima jako nástroj propagace firmy

Šmíd, Jaromír January 2014 (has links)
This thesis considers using machinima to aid company marketing activities, suitable programs analysis, design and creation of an advertisment video.

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