Predicting the performance of wells in compartmentalized reservoirs can be quite challenging to most conventional reservoir engineering tools. The purpose of this research is to develop a Compartmentalized Gas Depletion Model that applies not only to conventional consolidated reservoirs (with constant formation compressibility) but also to unconsolidated reservoirs (with variable formation compressibility) by including geomechanics, permeability deterioration and compartmentalization to estimate the OGIP and performance characteristics of each compartment in such reservoirs given production data. A geomechanics model was developed using available correlation in the industry to estimate variable pore volume compressibility, reservoir compaction and permeability reduction. The geomechanics calculations were combined with gas material balance equation and pseudo-steady state equation and the model was used to predict well performance. Simulated production data from a conventional gas Simulator was used for consolidated reservoir cases while synthetic data (generated by the model using known parameters) was used for unconsolidated reservoir cases. In both cases, the Compartmentalized Depletion Model was used to analyze data, and estimate the OGIP and Jg of each compartment in a compartmentalized gas reservoir and predict the subsequent reservoir performance. The analysis was done by history-matching gas rate with the model using an optimization technique. The model gave satisfactory results with both consolidated and unconsolidated reservoirs for single and multiple reservoir layers. It was demonstrated that for unconsolidated reservoirs, reduction in permeability and reservoir compaction could be very significant especially for unconsolidated gas reservoirs with large pay thickness and large depletion pressure.

Thesis (M.A.)--University of South Florida, 2003. / Title from PDF of title page. Document formatted into pages; contains 90 pages. Includes bibliographical references.

published_or_final_version / Physics / Master / Master of Philosophy

Zinc oxide (ZnO), as a Ⅱ-Ⅵ compound semiconductor with a wide direct band gap, has attracted great attention from the worldwide researchers for its potential application in the fields of spintronics and optoelectronics. At present research about the defects in ZnO and ZnO-based materials is still far from complete. The deep level defects in melted grown ZnO single crystal induced by helium ions implantation and electron irradiation, as well as their thermal evolution, were studied in this research using the technique of deep level transient spectroscopy (DLTS) and photoluminescence (PL). DLTS results indicated that, besides E3 (????~0.28 ????) trap which was widely observed in the as-grown ZnO samples, the deep level with ????~0.92 ???? was also indentified in the helium-implanted ZnO samples, which was introduced by the ion implantation and tentatively assigned to be the oxygen vacancy (VO). This deep level was removed after 350 oC annealing in argon gas. Annealing at 350 oC also brought along a new deep level with ????~0.66???? into helium-implanted samples which could be annealed out by 650 oC annealing in argon gas. The electron irradiation induced a deep level with ????~0.59 ???? into ZnO, which was probably associated with the singly charged state of VO. This deep level also tended to be removed at 350 oC annealing in argon gas. The PL spectra revealed that both helium implantation and electron irradiation could improve the bound-exciton peak. Helium implantation also introduced defects emission at 1.90 eV , which was the red luminescence band, into the ZnO single crystal materials. This red luminescence band peak might be associated with DAP recombination. Electron irradiation might restrain the green luminescence in ZnO single crystal. The fine structures could disappear as the measurement temperature increased, leaving the green luminescence band only. / published_or_final_version / Physics / Doctoral / Doctor of Philosophy

Mooring systems for floating facilities that are used offshore to produce oil and gas, consisting of individual mooring lines and foundations, are currently designed on the basis of individual components and on a case-by-case basis. The most heavily loaded line and anchor are checked under extreme loading conditions (hurricane and loop current) with the system of lines intact and with one line removed. However, the performance of the entire mooring system depends more directly on the performance of the system of lines and foundations rather than on the performance of a single component. In this study, a floating production system design originally developed by the industry consortium, DeepStar, was chosen for study. The mooring system was designed for three different nominal water depths: 1000, 2000 and 3000 m. It is a classic spar with steel mooring lines in 1000 m of water and polyester mooring lines in deeper depths. Based on simulated results of loads on mooring lines and foundations using a numerical model, reliability analyses were conducted using representative probabilistic descriptions of the extreme met-ocean conditions, hurricanes and loop currents, in the Gulf of Mexico. The probability of failure of individual mooring line components during a 20-year design life is calculated first, followed by that of a complete mooring line which consists of top and bottom chains, a steel cable or polyester rope at the middle and a suction caisson foundation, and finally that of the mooring system. It is found that foundations have failure probabilities that are more than an order of magnitude smaller than those for lines under extreme loading. Mooring systems exhibit redundancy in that the failure of the most heavily loaded component during an extreme event does not necessarily lead to failure of the system. The system reliability and redundancy are greater for the taut versus semi-taut systems and is greater for designs governed by loop current versus hurricane events. Although this study concerns about the mooring systems of a classical spar, the methodology of the reliability analysis and the conclusions made in this study may have important implications to the other deepwater mooring systems / text

published_or_final_version / Physics / Master / Master of Philosophy

Η παρούσα διπλωματική εργασία πραγματοποιήθηκε από 8/2013-9/2014 στο τμήμα ηλεκτρολόγων μηχανικών & τεχνολογίας υπολογιστών του πανεπιστημίου Πατρών, υπό την επίβλεψη του καθηγητή Γαβριήλ Γιαννακόπουλου. Σκοπός της παρούσας διπλωματικής είναι η σχεδίαση και ο έλεγχος στατικού σειριακού αντισταθμιστή με στόχο την αντιστάθμιση συμμετρικών και ασύμμετρων βυθίσεων τάσης σε ευαίσθητα φορτία. Αρχικά γίνεται μια γενική αναφορά στην δομή των συστημάτων ηλεκτρικής ενέργειας στην έννοια της ποιότητας ισχύος και στις διαταραχές που μπορούν να εμφανιστούν σε ένα σύστημα ηλεκτρικής ενέργειας. Έπειτα παρουσιάζονται μέθοδοι βελτίωσης της ποιότητας ισχύος και συγκεκριμένα των διαταραχών που οφείλονται σε βυθίσεις τάσεις. Κατόπιν περιγράφεται η δομή και ο τρόπος λειτουργίας της διάταξης που θα χρησιμοποιηθεί για την αντιστάθμιση της τάσης (Στατικός Σειριακός Αντισταθμιστής). Αναλύεται το σύστημα ελέγχου (Διπλός Διανυσματικός Ελεγκτής, Double Vector Controller) και παρουσιάζονται τα αποτελέσματα της προσομοίωσης διαφόρων τύπων βραχυκυκλωμάτων με την χρήση του Στατικού Σειριακού Αντισταθμιστή (Static Series Compensator). / The present work was carried out by 8 / 2013-9 / 2014 in the Department of Electrical and Computer Engineering,in the University of Patras, under the supervision of Professor Gabriel Giannakopoulos. The purpose of this project is the design and control of serial static compensator designed to compensate symmetrical and asymmetrical voltage drops to sensitive loads. Originally made ​​a general reference to the structure of power systems in the sense of power quality and disturbances that can occur in a power system. Then, the study methods for improving power quality and specific disorders caused dips trends. After describing the structure and function of the device to be used to compensate for the voltage (Serial Static Compensator). Analyzed control system, Double Vector Controller and presented the results of the simulation of various types of short circuits using the Serial Static Compensator

The effects of deep fat frying and oven baking on mass transfer (moisture loss and oil uptake), color and textural characteristics of chicken nuggets were studied. Deep fat frying was performed at three oil temperatures, namely 150, 170 and 190°C. The frying times were 1, 2, 3 and 4 min. Oven baking was accomplished at three temperature levels: 200, 220, and 240°C, and the baking times were 10, 15, 20 and 25 min. / Moisture content of the breading portion of the fried chicken nuggets decreased following a typical drying curve and ranged from 0.90 to 0.22 g/g (db), while the moisture content of the core portion of the chicken nuggets decreased almost linearly and ranged from 1.96 to 1.4 g/g (db). Fat contents of the breading and core portions increased linearly with time. Generally, frying temperature significantly affected the moisture contents of the breading and core. It also affected the fat content of the core but not that of the breading. (Abstract shortened by UMI.)

Anorexia Nervosa (AN) has the highest mortality rate of any psychiatric condition, and despite its recognition for centuries, remains a significant treatment challenge. Marked by firmly entrenched maladaptive beliefs about body, weight and food, as well as high rates of psychiatric comorbidity, AN is a chronic illness in a large proportion of patients. The neural substrates of AN are now beginning to emerge, and appear to be related to dysfunctional, primarily limbic, circuits driving pathological thoughts and behaviours. Deep Brain Stimulation (DBS) is a neurosurgical procedure where implanted electrodes are used to regulate activity in critical nodes comprising such aberrant circuits. The promise of DBS in motor-circuit conditions, such as Parkinson’s Disease, has driven it’s investigation in other circuit-based disorders, including some psychiatric conditions. Converging evidence from clinical and imaging literatures suggests that AN is in large part a disorder of emotional processing, wherein disordered mood, anxiety, and affective dysregulation contribute to disease maintenance and are obstacles to effective treatment. The subcallosal cingulate (SCC), a key medial frontal structure involved in affective processing, has further been directly implicated in AN relevant pathways. As such, this work had three broad objectives: i) to establish the safety and initial efficacy of SCC DBS in a group of chronic and highly-refractory AN patients; ii) to show that SCC DBS can have network wide cerebral metabolic influence, on AN-relevant circuits and structures; and, iii) to investigate whether structural brain features, including hippocampal volume changes, are correlated with clinical outcomes of DBS. Our results showed that DBS is safe in AN, and associated in some patients with significant improvements in mood, anxiety and, over time, weight and treatment-response. Imaging results further showed DBS to be associated with substantial changes in glucose utilization in disease-relevant circuits, with preliminary evidence supporting a relationship between hippocampal volume changes and clinical improvements. In the context of highly refractory disease, these promising results suggest that DBS can inform AN circuit models, and be explored as a novel therapeutic option for treatment-resistant patients.

Anorexia Nervosa (AN) has the highest mortality rate of any psychiatric condition, and despite its recognition for centuries, remains a significant treatment challenge. Marked by firmly entrenched maladaptive beliefs about body, weight and food, as well as high rates of psychiatric comorbidity, AN is a chronic illness in a large proportion of patients. The neural substrates of AN are now beginning to emerge, and appear to be related to dysfunctional, primarily limbic, circuits driving pathological thoughts and behaviours. Deep Brain Stimulation (DBS) is a neurosurgical procedure where implanted electrodes are used to regulate activity in critical nodes comprising such aberrant circuits. The promise of DBS in motor-circuit conditions, such as Parkinson’s Disease, has driven it’s investigation in other circuit-based disorders, including some psychiatric conditions. Converging evidence from clinical and imaging literatures suggests that AN is in large part a disorder of emotional processing, wherein disordered mood, anxiety, and affective dysregulation contribute to disease maintenance and are obstacles to effective treatment. The subcallosal cingulate (SCC), a key medial frontal structure involved in affective processing, has further been directly implicated in AN relevant pathways. As such, this work had three broad objectives: i) to establish the safety and initial efficacy of SCC DBS in a group of chronic and highly-refractory AN patients; ii) to show that SCC DBS can have network wide cerebral metabolic influence, on AN-relevant circuits and structures; and, iii) to investigate whether structural brain features, including hippocampal volume changes, are correlated with clinical outcomes of DBS. Our results showed that DBS is safe in AN, and associated in some patients with significant improvements in mood, anxiety and, over time, weight and treatment-response. Imaging results further showed DBS to be associated with substantial changes in glucose utilization in disease-relevant circuits, with preliminary evidence supporting a relationship between hippocampal volume changes and clinical improvements. In the context of highly refractory disease, these promising results suggest that DBS can inform AN circuit models, and be explored as a novel therapeutic option for treatment-resistant patients.