Made available in DSpace on 2014-06-12T18:29:21Z (GMT). No. of bitstreams: 2 arquivo8000_1.pdf: 1648781 bytes, checksum: e048c2be5c57968dba1e17be7e69255a (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2004 / O presente trabalho tem por finalidade avaliar a confiabilidade e descrever os achados da cintilografia de corpo inteiro com 99mTc-Sestamibi na avaliação préoperatória do câncer de tireóide; e ainda analisar a concordância entre os achados cintilográficos e histopatológicos dos nódulos tireoideanos. Um estudo observacional descritivo, tipo série de casos, foi realizado no período de julho de 2003 a janeiro de 2004. Foi avaliada através da cintilografia de corpo inteiro com 99mTc-Sestamibi a detecção da neoplasia primária da tireóide e de metástases em 16 pacientes, com PAAF sugestiva de neoplasia diferenciada da tireóide, sendo 10 mulheres, 6 homens, com média de idade de 46,1+14,5 anos. A confiabilidade dos achados cintilográficos foi medida através da concordância entre as análises das imagens cintilográficas realizadas pelos três observadores, utilizando-se o índice Kappa. A cintilografia detectou 15 (83,3%) nódulos tireoideanos, entre os quais 8 (53,3%) se localizavam no lobo direito, 6 (40%) no lobo esquerdo e 1 (6,7%) no istmo. Em 15 (93,7%) pacientes não foi detectada metástase regional; sendo observadas metástases regionais em 1 (6,3%) paciente. Metástases à distância visíveis à cintilografia não foram observadas em nenhum dos pacientes. Em relação à visibilização da neoplasia primária tireoideana e de metástase regional e/ou à distância, a concordância entre os observadores foi de 100% (kappa=1;p=0,00). Obsevou-se concordância entre os achados cintilográficos e histológicos em 88,9% dos casos. A cintilografia de corpo inteiro com 99mTc-Sestamibi mostrou-se um método útil na detecção da lesão primária e secundária de câncer diferenciado de tireóide, com grau perfeito de confiabilidade, podendo contribuir para o estadiamento do câncer diferenciado de tireóide

Annual allochthonous leaf litter inputs to temperate headwater streams provide a major contribution to the energy and carbon dynamics of the system, with whole seasonal cycles being determined by leaf litter inputs. Although a number of different physical and hydraulic factors have been linked to leaf retention, the mechanism of leaf retention has not been fully quantifed. A series of flume experiments investigated how leaf retention and the flow structure varied with bed heterogeneity, boulder submergence and boulder density. Two set-ups were used; a flat bed consisting of two physically different substrates, sand and pebbles, under the same `global' conditions and an idealised situation using uniformly sized concrete hemispheres placed in a staggered array directly on the flume bed, where the boulder submergence and density was varied systematically for a constant discharge. Saturated leaves were added, with retention number and locations being recorded. Detailed three dimensional velocity measurements were taken throughout a control volume. Signifcantly higher retention was observed on the larger substrate and the presences of protrusions were found to be important. Boulder density was signifcantly related to both the retention effciency and retention per boulder with an optimum density occurring at the intermediate density. Flow depth was found not to be signifcantly related to any measure of retention. The presence of the boulders generated a number of previously identified coherent structures within the flow. Increase in boulder density produced larger wakes, stronger crossstreamwise and vertical velocities and increased TKE within the boulder flow layer. The flow structure did not change with boulder submergence but with increasing boulder density it changed from isolated boulders with separate wakes to wake-interfering flow where the wakes of adjacent boulders were observed to `overlap'. A strong relationship was exhibited between the spatially-averaged near-bed shear stress immediately upstream of the boulder and retention. Retention increased as the shear stress neared zero, and decreased with both large negative and positive shear stresses. Maximum retention occurred under isolated flow conditions, with an increase in density providing increased retention due to a greater number of retention locations. However, a change in flow conditions to wake-interaction resulted in a decrease in retention.

Uma média de 80 % dos radiofármacos usados nas clínicas são marcados com 99mTc por suas propriedades físicas adequadas e fácil obtenção através de geradores de 99Mo/99mTc. A Diretoria de Radiofarmácia (DIRF) do IPEN-CNEN/SP desenvolveu um gerador cromatográfico tipo gel de MoZr com 99Mo produzido pela da reação 98Mo(n,)99Mo que ocorre no reator Nuclear IEA-R1 do IPEN-CNEN/SP. O gel é composto de molibdato de zircônio com volume de eluição de 12 mL com uma atividade de 11100 MBq (300 mCi) produzindo uma concentração radioativa de 925 MBq (25 mCi)/mL. O gerador de fissão produz uma concentração radioativa maior, de 1850 MBq (50 mCi)/mL. Pretende-se com esse trabalho desenvolver um gerador 99 Mo/99mTc tipo gel com a qual se possa eluir 99mTc obtendo-se uma concentração radioativa adequada para atender a demanda de mercado sem perder a qualidade. Foram desenvolvidos dois tipos de sistemas de concentração o único e o em série. O sistema mais adequado para o gerador de 99Mo/99mTc do tipo gel de MoZr estéril e automatizado à vácuo foi o sistema de concentração em série utilizando o cartucho Dionex 2,5 cc/QMA. O gerador de gel é eluído com 10 mL de solução de NaCl 0,1 % sendo o pertecnetato retido no cartucho aniônico QMA e eluído com 4 mL de solução de NaCl de 0,9 %. O processo dura no máximo 30 minutos. A eficiência de eluição do sistema de concentração foi de 90 %. No início de 2009 aconteceu uma crise mundial do abastecimento de 99Mo fazendo com que surgisse a necessidade do desenvolvimento de tecnologias alternativas para a produção de geradores de 99Mo/99mTc utilizando 99Mo produzido por fissão ou o desenvolvimento de um método adequado para estender a vida útil deste gerador. Os resultados deste trabalho mostraram que é possível utilizar o mesmo sistema de concentração desenvolvido para o gerador de gel, o que levará a um fator de concentração de 3 para o 99mTc eluído. / On average 80% of the radiopharmaceuticals used in Nuclear Medicine are labeled with 99mTc due to its physical properties and easy attainment through of 99Mo/99mTc generators. The Directory of Radiopharmacy (DIRF) of IPEN-CNEN/SP developed a gel type chromatographic generator of MoZr with 99Mo produced by 98Mo(n,)99Mo reaction that occurs at the IEA-R1 Nuclear Reactor. The gel is composed of zirconium molibdate with elution volume of 12 mL with an activity of 11100 MBq (300 mCi) producing a radioactive concentration of 925 MBq (25 mCi)/mL. The fission generator gives a higher radioactive concentration around 1850 MBq (50 mCi)/mL. The aim of this work is to study a system of post-elution concentration of 99mTc for the attainment of a high enough radioactive concentration to meet the demands of the market, with a proved quality. Two types of systems of post-elution concentration were developed: the single and the tandem. The most appropriate system for the gel generator of 99Mo/99mTc, being at the same time sterile and vacuum automated, was the tandem system using Dionex 2.5 cc/QMA cartridges. The gel generator is eluted with 10 mL of solution of 0.1% NaCl and the pertechnetate anion is retained in the QMA cartridge and further eluted with 4 mL of saline. The process takes no more than 30 minutes. The elution efficiency of the system of concentration was 90 %. At the beginning of 2009 a global crisis in the supply of 99Mo took place making it necessary the development of alternative technologies for the production of 99Mo/99mTc generators using fission produced 99Mo and the development of an appropriate method to extend the useful life of this generator. The results of this study showed that the same system developed for the post- concentration of the gel generator can be employed for the fission generator, using the tandem system, giving a concentration factor of 3 for the elution of 99mTc.

This research work is aimed at developing a coupled surface-groundwater flow model which can be used to simulate both surface and groundwater flow at the swash zone. The coupled model is then used to investigate the effects of seepage on swash hydrodynamics as well as morphodynamics. The surface flow model was originally developed by Briganti et al. (2012), which solved a system of equations consisting of the Nonlinear Shallow Water Equations and the bed-evolution (Exner) equation with bed shear stress computed using a boundary layer model without seepage developed in Briganti et al. (2011). In this work, a groundwater flow model which solves Laplace's equation following the approach of Li and Barry (2000) is incorporated into the surface flow model, which allows computation of seepage into the bed (infiltration) and out of it (exfiltration). The seepage is then included into the boundary layer models to incorporate the effects of seepage on the bed shear stress. To assess the performance of the surface flow model, dam-break cases are simulated and compared against analytical and quasi-analytical solutions from literature. Firstly, the dam-break case on a fixed bed is simulated and compared against Ritter solution (Stoker, 1957) and then the dam-break case on a mobile bed is verified against Zhu (2012)'s quasi-analytical Riemann solver. Both models show good agreement with their respective reference results. Subsequently, the verification of the groundwater flow model is conducted by simulating phreatic surface flow through a rectangular dam and comparing the results against those of Kazemzadeh-Parsi and Daneshmand (2012). Next, the coupled surface-groundwater flow model is validated by reproducing surface and groundwater flow in the prototype-scale BARDEX II experiment. Firstly, the groundwater flow cases (higher and lower lagoon levels than the initial sea level) without surface water waves are simulated. The comparison of time-averaged numerical phreatic surface elevations against the experimental data shows excellent agreement. Next, the surface water waves are included and the simulations are repeated for the previous two cases. The groundwater comparisons again yield good agreement and the hydrodynamics of the surface waves show reasonably close agreement. Increase in exfiltration is observed to result in an increase in boundary layer thickness, which subsequently results in smaller velocity gradients and a decrease in bed shear stress using exfiltration included BBL model of Cheng and Chiew (1998). Conversely, the increase in infiltration causes a decrease in boundary layer thickness, which results in an increase in bed shear stress using infiltration included BBL model of Chen and Chiew (2004). The model results also show that the boundary layer effect by infiltration is opposed by the 'continuity effect' in the swash zone (Baldock and Nielsen, 2009). The model results show that an increase in infiltration rates is observed to increase slip velocity, and also compares well against the empirical equation derived in Chen and Chiew (2004). Furthermore, the rate of increase (decrease) of bed shear stress due to infiltration (exfiltration) compares favourably against the empirical trend line of Nielsen et al. (2001) and experimental data of Conley (1993). Additionally, the boundary layer model bed shear stress is compared against single swash event bed shear stress results from Kikkert et al. (2013) experiment and shows reasonably good agreement. The boundary layer models can be used to account for seepage effects on bed shear stressfor a larger range of ventilation parameters than Nielsen et al. (2001), which would improve morphodynamical modelling on permeable beds in the swash zone. Finally, the performance of the coupled surface-groundwater model is further investigated by simulating the BARDEX II experiment with a mobile bed. The swash zone water depth compares well with the BARDEX II experimental results. Although the corresponding dataset for velocity is shown to be rather unreliable during backwash, during uprush, the comparison is very close. Using both Meyer-Peter-Müller (MPM) and Grass sediment transport models, similar morphodynamical patterns are observed. The bed change comparisons against experimental results show that the model predicts the same order as well as the same pattern of erosion. However, deposition in the upper swash zone is not predicted by the model which could be due to the presence of significant amounts of suspended sediment which would lead to onshore sediment transport (Pritchard and Hogg, 2005, Zhu and Dodd, 2015) which is not accounted for in the simplified numerical model. The model is shown to be robust and flexible and it is capable of simulating both surface and groundwater flow simultaneously on fixed or evolving bed.

Thesis(MSc(Med)Pharmacy)) -- University of Limpopo, 2011. / ABSTRACT Introduction: Non-invasive detection of tumour hypoxia theoretically adds value to the. outcome of treatment; however the practical aspect of using 99mTc-EC-MN in cervical cancer remains un-attempted. 99mTc-EC-MN has been used to indirectly detect hypoxia in many tumours (head and neck) and other hypoxic states such as strokes and MI. This study aims to determine the value of using this tracer in early stage cervical cancer. Objectives: This study aimed to investigate the use of 99mTc-EC-MN to determine the degree of hypoxia in cervical cancer. The original study design was to determine whether SPECT with 99mTc-EC-MN would detect ~l'poxi~cervicalc;ancer 'lesions and compare the results with the histological report. The practice of safe handling of radiopharmaceuticals and gaining knowledge in conducting research formed part of the secondary objective of the study. Due to circumstances beyond the control of the researcher, the focus of the study changed from a clinical to a chemistry-based project. Method development: Safety of EC-MN was tested through determination of the labelling efficiency with pertechnetate initially by ITLC-SG. Ethyl acetate, ethanol, saline and ac;etone were selected to develop 99mTc-EC-MN chromatograms to identify the system which best displays separation. Radio-ITLC displayed multiple peaks due to high residual activity in ethyl acetate- and acetone-developed scans. Saline- and ethanol-developed scans showed better separation of 99mTc-EC-MN but separation from free pertechnetate was difficult. Radio HPLC coupled with a diode array detector was used to successfully separate the labelled product, 99mTc-EC-MN from free pertechnetate, thereby achieving good radiolabelling. Clinical application: After the relative safety of the product was established, it was injected IV in the selected patient who had early stage cervical carcinoma. Clinical examinations which included pre-operative WBC, ultrasonography of the kidneys and bladder, and chest x-rays were performed. Histological analysis was performed after surgery and gave results that were insufficient to conclude the absence or the presence of tumour hypoxia. Detection of 99mTc-EC-MN was analysed from blood-flow and -pool images, thyroid and pelvic static, SPECT, and WBS images obtained from a gamma scintillation camera. Faint hot spots consistent with low levels of free pertechnetate were detected in the salivary glands. Hot areas which paralleled the bio-distribution of the 99mTc-EC-MN were also detected in the thyroid, liver, intestines, kidneys, and bladder. There was no tracer detection in the pelvic area. Conclusions: Experience was gained in QC procedures and aseptic preparation of radiopharmaceuticals, and in conducting and co-managing a chemical and clinical based research. Radiochemically related findings demonstrated that tin (II) chloride can be solubilised in water; 99mTc-EC-MN migrates with the solvent front in saline and ethanol developed ITLSG scans; and ITLC cannot sufficiently separate 99mTc-EC-MN from free pertechnetate. Successful labelling of EC-MN was confirmed by scintigraphy and showed tracer distribution that parallels those previously described. Successful labelling of EC-MN with 99mTc can be achieved up to two years after kit manufacture given appropriate storage conditions for the EC-MN. The hypoxic status of the tumour remained inconclusive; therefore the prognostic impact of 99mTc-EC-MN in cervical cancer remains unknown. Recommendations: Product stability and potential expiry should be available for all products, even in the developmental stages and particularly for clinical trials. A simple QC method to separate 99mTc-EC-MN from free pertechnetate should be developed. Further studies are required in order to confirm the efficacy of 99mTc-EC-NM in determining tumour hypoxia in cervical cancer. If a suitable animal model is not available, patients with known cancer tissue hypoxia should be evaluated and compared with those who are non-hypoxic

The global offshore oil and gas industry is constantly challenged with complex operational activities, increasing uncertainties, strict regulations and delicate health, safety and environmental issues. That has made offshore deepwater drilling operation the most time sensitive activity in the upstream oil and gas industry with high probabilities of cost and time overrun. Unfortunately, the current cost estimation models are not robust enough to deal with the multi-variables associated with cost overrun in the offshore deepwater drilling industry in the Sub-Sahara Africa. This study therefore developed a mathematical model that can give accurate estimations with limited data, precisely capture risk elements and factor probability results of all the possible cost variables in the offshore deep-water drilling operations. The study combined Bayesian approach with Activity-based costing (ABC) model to address the limitations of most existing models using primary data collected and secondary data extrapolated from past literatures, published official drilling data and companies’ financial and operational reports. The integrated model showed promising results when tested against three offshore fields’ data across three different countries (Erha-Nigeria, Jubilee-Ghana and Luanda-Angola). Findings from the analysis of the three fields showed cost estimates to be 10% more accurate than the estimates from existing cost estimation models in Sub-Sahara Africa. Further analysis also demonstrated the ability of the model to reduce the regional cost overrun from about 40% to 20%, thereby underlining the efficacy of the model in estimating offshore drilling cost. The strengths, weaknesses as well as the implications of using the model were also discussed. Additionally, the study developed an improved elicitation framework and guidelines to help facilitate cost estimation in the offshore deep-water drilling operations based on the Bayesian approach. The developed elicitation process was used to collect the primary data for this work and generated probabilistic response on the known unknowns and unknown unknowns’ variables in the oil and gas industry Finally, the research analysed and produced findings on cost reduction techniques for the offshore drilling industry.

The UK sector of the North Sea is a mature oil and gas basin subjected to some of the harshest offshore environments with a majority of the oil and gas installations approaching or having exceeded their original design life, often specified as 25 years. It is likely that the operation of these installations will continue for a substantial period in the foreseeable future. However, the ageing nature of these installations present significant challenges to the delivery of high standards of health and safety required by the UK Health and Safety Executive. The issue of ageing installations has been shown to be an important factor in offshore incidents and accidents, leading to an increased risk of accidental loss of hydrocarbon and failures due to equipment deterioration. Two major hazards resulting from ignition of accidental hydrocarbon release are fires and explosions. Failure to minimise the effects of fires and explosions can bring about significant damage to the structural integrity of offshore installations and pose a risk to personnel safety as evidenced by the 1988 Piper Alpha Disaster and the 2010 Deepwater Horizon Explosion and Oil Spill. This thesis presents a practical tool that can be used to predict the costs, risks and service reliability of any given asset management policy for an offshore oil and gas installation. The tool is implemented using a standard Petri Net technique with already adopted and newly proposed high level extensions, and fluid flow modelling technique. The tool is further divided into two sub models that work in conjunction with one another: (1) the Petri Net based Offshore Safety System Degradation and Maintenance Model and (2) the Offshore Fire and Explosion Model based on fluid flow modelling techniques. The aim of the Offshore Safety System Degradation and Maintenance Model is to concurrently simulate the degradation, failure, inspection and maintenance of four safety systems which includes the fire and gas detection system, process isolation, process blowdown, and the deluge system. Simulation of the model generates a variety of statistics such as the estimated operational costs and unavailability associated with implementing any given asset management policy. The Offshore Fire and Explosion Model is then used to model the occurrence of a hydrocarbon leak from a process vessel located within three enclosed modules; wellhead, separation and compression, of an offshore installation. The aim of this model is to predict the frequencies of fires and explosions in the event that the safety systems previously modelled in the Offshore Safety System Degradation and Maintenance Model fail to function on demand in the presence of an ignition source. The model utilises fluid flow modelling to calculate parameters such as the hydrocarbon discharge rate, gas cloud build-up and dispersion, oil-pool build-up and reduction. These parameters can then be used to predict the magnitude of the fires and explosions in terms of the flame length produced in the event of a fire and the overpressures generated in the event of an explosion. The results and statistics generated are highly beneficial to offshore asset operations managers as they can be used to predict the number of maintenance interventions necessary to ensure safety systems are in an acceptable condition. From this, associated costs can be determined enabling offshore managers to allocate resources and budget accordingly. Finally, an optimisation study is carried out using Genetic Algorithm to identify the optimum inspection, maintenance and repair strategy for the offshore safety systems with an acceptable risk level. The methodology presented in this research considers the offshore safety systems and the processes described above in more detail compared to previous literature associated with asset management offshore oil and gas installation. Additionally, the research demonstrates the suitability of Petri Nets for integrating fire and explosion modelling within the asset management framework which is first of its kind. The model can be successfully used to predict costs, risks and service reliability, and to support asset management decisions when the model is implemented in an optimisation framework.

With the increase in human activity associated with the recent rise in Kuwait’s oil production, there is greater need for an optimised solution to protect the Kuwaiti coastline and islands from wave attacks and erosion. This thesis describes a programme of research conducted to support the development of a cost-effective method of protecting the Kuwaiti coastline with a breakwater system that also provides an opportunity to generate energy by locally increasing the energy density of waves to make wave energy conversion (WEC) more efficient, cost-effective and commercially competitive. A comprehensive review of the historical development and current state-of-the-art regarding breakwater and WEC technologies is presented. On the basis of these evaluations, a floating breakwater combined with point absorber device is identified as appropriate for use in the Kuwaiti near shore marine environment. The need for increasing the local energy density at the point absorber is highlighted and the concept of using a parabolic concentrator in combination with point absorber is suggested and developed. An analytical study extends the understanding of the role of damping in the response of an idealised point absorber device. A steady-state harmonic model is developed to simulate the motion of a single buoy with one degree of freedom (heave) along the vertical axis to optimise its geometrical and control parameters and maximise its power absorption from incident waves. Evaluating different buoy shapes namely: bullet, spike, and bi-cone (60o/120o) indicates that for each buoy shape, there is an optimum operating range for the power take-off (PTO) that drives the generator where wave energy capture and thus electrical power would be greatest. In the model, comprising a spring-damper system, the PTO is represented as a damper with a constant damping coefficient (〖 c〗_1) and the radiation force is represented by a linear radiation damping term (〖 c〗_2). The model reveals that the best performance is obtained at the optimum value for c_1 which is c_1= c_2=k/ω. This condition is met when the buoy with optimum mass is at resonance with the peak frequency of the sea state at ω^2=k/m. Evaluating the power absorption as a function of 〖 c〗_2 in the model also reveals that at resonance, a buoy of any shape will have two types of behaviour: one driven by low radiation damping and the other by high radiation damping range of values. Operation in the low 〖 c〗_2 region is difficult to achieve in practice, and hence, it is recommended that devices should be designed to operate in the high 〖 c〗_2 region to maximise power capture. Data is presented from wave tank testing conducted using a flume at the Kuwaiti Institute for Scientific Research (KISR). This is used to evaluate the capability of the proposed parabolic concentrator elements to increase potential wave energy harvesting. A wealth of data, both visualisation and numerical, was obtained and this compares well with the computational analyses. The results indicate that a parabola-buoy system would be capable of absorbing almost 260 kW of power at prototype scale (1:16). A computational modelling approach using the commercial CFD code ANSYS-Fluent is developed, applying the volume of fluid approach combined with a wave boundary condition. The KISR wave tank was modelled with parabolic element installed and data is compared to that obtained experimentally. Good agreement between CFD and experimental data is obtained validating the modelling choices made. Additional modelling results for the behaviour of waves near an anchored buoy in combination with a parabolic concentrator are presented. The work presented in this thesis shows that there is the potential for substantial benefit for power absorption through using a combined parabolic concentrator-point absorber device. Future modelling work with fluid-structure interaction and moving buoy will permit further optimisation and development paving the way for full-scale developments in the future.

This thesis proposes the initial stages of the development of a NUI – Asset Integrity Case (Normally Unattended Installation). An NUI – Asset Integrity Case will enable the user to determine the impact of deficiencies in asset integrity and demonstrate that integrity is being managed. A key driver for improved asset integrity monitoring is centred on the level of accurate reporting of incidents. This stems from incidents to key offshore systems and areas. For example, gas turbine driven generators where 22% of fuel gas leaks were undetected with 60% of these 22% having been found to have ignited. Accordingly, there is a need for dynamic risk assessment and improved asset integrity monitoring. The immediate objective of this research is to investigate how a dynamic risk model can be developed for an offshore system. Subsequently, two dynamic risk assessment models were developed for an offshore gas turbine driven electrical power generation system. Bayesian Networks provided the base theory and algorithms to develop the models. The first model focuses on the consequences of one component failure. While the second model focuses on the consequences of a fuel gas release with escalated fire and explosion, based upon several initiating failures. This research also provides a Multiple Attribute Decision Analysis (MADA) to determine the most suitable Wireless Sensor Network (WSN) configuration for asset integrity monitoring. The WSN is applied to the same gas turbine system as in the dynamic risk assessment models. In the future, this work can be expanded to other systems and industries by applying the developed Asset Integrity Case framework and methodology. The framework outlines the steps to develop a dynamic risk assessment model along with MADA for the most suitable remote sensing and detection methods.

Made available in DSpace on 2014-10-09T12:37:36Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:18Z (GMT). No. of bitstreams: 1 04860.pdf: 16120223 bytes, checksum: e94349c100b463afba7f046b474fbb09 (MD5) / Tese (Doutoramento) / IPEN/T / Massachusetts Institute of Technology - Cambridge, Mass - MIT