Risk is an uncertain event which will cause deviation in pre-defined objectives, if it occurs. Risk management aims to identify risks, quantify their impacts and develop strategies to mitigate them to ensure project success. Within the context of risk management studies, risk models are usually designed to simulate the project performance under various scenarios. For risk modeling, the statistical link between the risk events and their consequences is scrutinized. However, this approach has a limitation as the influence of the &ldquo / system&rdquo / is neglected during modeling the relation between risk sources and consequences. The term &ldquo / vulnerability&rdquo / is used to describe internal characteristics of a system which influence this relationship. Management of vulnerabilities in addition to risks is essential for the success of risk management. However, there is no consensus on an appropriate definition of vulnerability parameters and their influence on construction projects. One of the aims of the study is to identify the vulnerability factors for construction projects and to propose a framework which portrays the relationship between risk and vulnerability. For this purpose, a detailed literature survey is performed to define the determinants influencing the level of vulnerability. In addition, case studies were conducted with Turkish contractors to explore the relationships between risk events, project vulnerabilities and project performance. Another objective of the study is to propose a risk and vulnerability ontology which provides a definite vocabulary and machine-comprehensible common understanding of the developed framework. Developed ontology will further be used to form a database for risk and vulnerability management.

By the evolving application of technology in the oil and gas fields, the volume of gathered information through the dynamic surveillance gets enormous. The importance is lying not only in the regular storage and standalone usage of such a big volume of data but also analyzing and integrating them in the light of alternative sources of data in order to turn the data to valuable field performance information. It is aimed to investigate role of the real time (bottom hole temperature gauges and distributed temperature sensor) and dynamic surveillance (PBU/PFO, production test results etc.) data in effectively managing ACG field. The case study has been carried out by integrating various sources of surveillance data (well test, DTS, PBU) with flowing bottomhole temperature and pressure in order to show the response of production wells to offset producers as wells as water injection and gas injection wells. It has been observed that the reservoir pressure change impacts on the GOR trend which in turn is reflected on the FBHT by means of Joule-Thomson effect. Analyzed Azeri filed examples shows that the change in FBHT is dependant on the rate of change of the reservoir pressure as well as the gas saturation. Also, there are several Azeri field examples that confirm the observed FBHT and FBHP fluctuations is the informer of the instability in the lift performance as a result of GOR decline. Along with above study, investigation of correlation between FBHT and measured GOR from an Azeri production well revealed that there exists a flow regime dependent linear correlation between these parameters. Such a correlation is applied in Azeri wells to predict the &lsquo / real-time&rsquo / GOR in the production wells.

Hydropower helps countries meet their energy needs in an economically, environmentally, and socially sustainable way while saving money and increasing energy security and self-reliance. Being one of the fastest developing countries, electricity demand of Turkey has been increasing and is expected to increase in the future. Untapped hydropower potential is among the prospective alternative resources to supply this demand. Developing a hydropower project requires a great deal of expertise in multiple disciplines. RETScreen software developed by CanmetENERGY helps the planners and decision makers to assess the feasibility of renewable energy projects at the pre-feasibility and feasibility stages. This study is an application of RETScreen to assess the feasibility of alternative formulations for Niksar HEPP, a small hydropower project which is under construction in Turkey. Three alternative formulations are generated and their economic performances are evaluated and compared. First, optimum design discharges are calculated and then economical analysis is conducted for various electricity export rates by RETScreen for all the alternatives. This study provides a detailed literature review on hydropower and its economical, social and environmental aspects, and shows how RETScreen can be used in assessing the economical feasibilities of the current formulation for Niksar HEPP and its alternative schemes.

Thesis (Ph.D.)--Brown University, 2008. / Vita. Advisor : Anubhav Tripathi. Includes bibliographical references.

<p> The power conversion efficiency of organic thin film solar cells must be improved before they can become commercially competitive alternatives to silicon-based photovoltaics. Exciton diffusion and charge carrier migration in organic films are strongly influenced by film morphology, which can be controlled by the substrate temperature during film growth. Zinc-phthalocyaninelbuckminsterfullerene bilayer film devices are fabricated with substrate temperatures between 25&deg;C and 224&deg;C and their solar cell performance is investigated here. The device open-circuit voltage, efficiency, and fill factor all exhibit peaks when films are grown at temperatures between 160&deg;C and 180&deg;C, which is likely a result of both the increase in shunt resistance and reduction in undesirable back diode effects which occur between l00&deg;C and 180&deg;C. The device performance can also be attributed to changes in the film crystallite size, roughness, and abundance of pinholes, as well as the occurrence of crystalline phase transitions which occur in both zinc-phthalocyanine and buckminsterfullerene between 150&deg;C and 200&deg;C. The unusually high open-circuit voltage (1.2 V), low short-circuit current density (0.03 mA/cm²), and low device efficiency (0.04%) reported here are reminiscent of single layer phthalocyanine-based Schottky solar cells, which suggests that pinholes in bilayer film devices can effectively lead to the formation of Schottky diodes.</p>

<p> Manufacturers, specifically small machine shops, find it difficult to compete with the capabilities of large manufacturers. If these small shops are not certified to a recognized standard such as AS9100, sales become even harder.</p><p> Small businesses need assistance in understanding and achieving the certifications requirements for a quality management system (QMS), which requires management's commitment and total buy-in for a proper implementation plan that involves the entire staff.</p><p> The objective of this project is to develop a quality manual that outlines the total process for the implementation of an AS9100 QMS. The author has researched various guidance documents that provide an understanding of the requirements, ownership, targets, and steps for applying appropriate resources. </p><p> A Gap analysis has been completed to determine the status of the QMS and identify what actions should be taken. Documents and processes have been developed with input from the management team, leading to a successful certification process.</p>

<p> Building complex physics-based systems in a timely cost-effective manner, that perform well, meet diverse user needs, and have no bad emergent behaviors is a challenge. To meet these requirements the solution is to model the physics-based system before building it. Modeling and Simulation capabilities for these type systems have advanced continuously during the past 20 years thanks to progress in the application of high fidelity computational codes that are able to model the real physical performance of system components. The problem is that it is often too time consuming and costly to model complex systems, end-to-end, using these high fidelity computational models alone. Missing are good approaches to segment the modeling of complex systems performance and behaviors, keep the model chain coherent and only model what is necessary. Current research efforts have shown that using multi-fidelity and/or surrogate models might offer alternative methods of performing the modeling and simulations needed to design and develop physics-based systems more efficiently. This study demonstrates that it is possible reduce the number of high fidelity runs allowing the use of classical systems engineering analysis and tools that would not be possible if only high fidelity codes were employed. This study advances the systems engineering of physics-based systems by reducing the number of time consuming high fidelity models and simulations that must be used to design and develop the systems. The study produced a novel approach to the design and development of complex physics-based systems by using a mix of variable fidelity physics-based models and surrogate models. It shows that this combination of increasing fidelity models enables the computationally and cost efficient modeling and simulation of these complex systems and their components. The study presents an example of the methodology for the analysis and design of two physics-based systems: a Ground Penetrating Radar (GPR) and a Nuclear Electromagnetic Pulse Bounded Wave System.</p>

<p> Paracrine signals, essential for the proper survival and functioning of tissues, can be mimicked by delivery of therapeutic proteins within engineered tissue constructs. Conventional delivery methods are of limited duration and are unresponsive to the local environment. I developed a system for sustained and regulated delivery of paracrine signals by encapsulating living cells of one type in alginate beads and co-suspending these cell-loaded particles along with unencapsulated cells of a second type within a 3D protein gel. By using cells as particulate protein delivery sources in a 3D gel, an array of soluble factors are delivered in an adaptable manner throughout the gel material for as long as the cells are alive and healthy.</p><p> This system was applied to vascular tissue engineering by placing human placental microvascular pericytes (PCs) in the particulate alginate phase and human umbilical vein endothelial cells (HUVECs) in the protein gel phase. Particle characteristics were optimized to keep the encapsulated PCs viable for at least two weeks. Encapsulated PCs were bioactive <i>in vitro</i>, secreting multiple angiogenic proteins for up to 7 days, including hepatocyte growth factor and vascular endothelial growth factor, and responding to externally applied HUVEC-derived signals. Medium conditioned by encapsulated PCs stimulated the formation of longer cumulative sprout lengths (1.4x) in an HUVEC sprouting assay.</p><p> Encapsulated PCs were biologically active in the complete dual-cell system described. These encapsulated PCs influenced HUVEC behavior in the surrounding gel by enhancing the formation of vessel-like structures, when compared to empty alginate bead controls. Significantly more multi-cell cords (3.1x) and tubes (2.6x) were formed by HUVEC in the presence of encapsulated PC. Additionally, multi-cell cords were significantly longer (1.4x) and lumen diameter was significantly smaller (1.5x) than in control gels containing empty alginate particles.</p><p> Encapsulated PCs appear to lead to important functional consequences in the developing vascular network: paracrine signals from the entrapped PCs lead to smaller lumen diameters in vessels formed by HUVEC that were suspended in protein gels and subcutaneously implanted in the abdominal wall of immunodeficient mice. In native <i>in vivo</i> microvessels, PCs reside in the basement membrane and directly contact EC tubes. Previous studies, in which EC-PC contact was permitted, showed that the presence of PCs lead to smaller vessel diameter. These earlier studies hypothesize that this limitation of lumen diameter requires EC-PC contact, and was due to a physical restriction. Our studies, on the other hand, suggest that paracrine signals contribute to this control of vessel diameter.</p><p> I conclude that alginate-encapsulated cells can provide functional paracrine signals within engineered tissues. The dual-cell system described in this dissertation can be used both as an engineering therapy to adaptably deliver an array of paracrine signals and as a platform for studying the purely paracrine interactions between two cell types in the absence of cell-cell contact.</p>

Bandsawing is a preferred method used by steel stockholders and steel users in industry for cutting-off to size in the primary and secondary processes. The state-of- the-art features in current industrial bandsaw machines have transformed this method for cutting-off stock to size into a hi-tech operation capable of storage and handling. This method is particularly suitable for use in engineering factories involved in fast, highly automated mass-production techniques, providing the user with continuous batches of cut-to-length materials. Bandsaw machines have now superseded power hacksaws and circular saws in cutting rate and lower kerf loss due to better computer- controlled saw machines and improved blade designs (bi-metal HSS, carbide tipped). Although, there have been some new developments in bandsaw blades (tooth geometry, band material etc.) there are continuous new demands made on the bandsaw blades by materials engineers, challenged with introducing new materials to satisfy the needs of the design engineers, e.g. aerospace industry. There is therefore a need to improve the bandsaw blade. In order to do this we need to have an understanding of the mechanics of the cutting process associated with bandsawing and the various parameters affecting cutting forces, specific cutting energy, metal removal rates etc. One of the primary problems in evaluating metal bandsaws and developing newer variants, including new saw tooth materials, their heat treatment, or special tooth forms and quality, has been the use of costly and time consuming sawing tests. Furthermore, there are no simple ways of quantitatively evaluating the performance and life of these bands during sawing. Traditional method used by machine operators to assess the performance of blades only give global data, which is difficult to apply to individual teeth. Therefore there is a need to develop "time compression" test methods for evaluating the performance of bandsaw blades to replace full bandsaw blade testing. The work presented in this thesis is on the development of a single tooth testing method to simulate the intermittent cutting action of a bandsaw blade. Cutting tests have been performed to assess the testing method by comparing single tooth test results to full bandsaw blade test results. The test method developed is capable of producing scientific data for bandsawing associated with forces, metal removal rate and specific cutting energy when cutting a variety of workpiece materials at different speeds and feeds. Thus, it can be used as a substitute to full bandsaw blade testing. The cutting data for the workpiece materials tested using the single tooth test method was obtained in 25% of the full bandsaw blade evaluation time. This represents a significant saving in time and cost, which should prove useful to design engineers when designing and testing new prototype bandsaw blades for the future needs of the steel and manufacturing industry involved in metal cutting.

Almost 50 years of thermophotovoltaic (TPV) research from various sectors has resulted in a variety of potential applications and TPV technology options. In this work the potential of commercial TPV applications is assessed with specific reference to the UK. The assessment considers competing technologies for electricity generation, namely solar photovoltaics, external and internal heat engine generators, electro¬chemical cells and direct heat-to-electricity conversion devices. Electricity generation by TPV conversion from waste heat of industrial high-temperature processes is identified as one of the most suitable TPV applications. This market is examined in more detail using three specific high-temperature processes from the iron and steel and the glass sectors. Results are extrapolated to the entire UK high-temperature industry and include potential energy and CO2 savings. This work gathers knowledge from TPV and other literature sources and evaluates the technological options for the heat source, the radiator and the PV cell for a TPV system. The optical control in terms of the angular, spatial and in particular spectral radiation distributions in cavities is identified as a specific factor for TPV conversion and critical for a system design. The impact of simultaneous radiation suppression above and below the PV cell bandgap on an ultimate efficiency level is examined. This research focuses on fused silica (SiO2) in TPV cavities and examines the aspects of radiation guidance by total internal reflection and spectral control using coupled radiative and conductive heat transfer. Finite volume modelling and experimental work have examined the radiator-glass-air-PV cell arrangement up to a SiO2 thickness of 20 cm. Both show that the efficiency improves for an increased SiO2 thickness. Finally, the novel concept of a TPV cavity consisting of a solid dielectric medium is assessed.