Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains x, 61 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 59-61).

To ensure energy security, the first to know what is energy, and second, what are the factors of non-security, means that the challenge of energy security. Finally, puts forward some policy or in the case of a reasonable method to solve it according to these problems. At present, energy security is facing two challenges of structural crisis and crisis management system. Concretely, main problems in that security are analyzed, which are considered to affect China and mostly embody in such four big areas as the great pressure in energy supply, the scarcity of relative energy resources, foreign oil dependence is too large, crisis management systems of energy security, the shortage of green energy. Furthermore the counter measures concerned are proposed, including saving energy and increasing the energy utilization rate, to establish strategic energy reserves, strengthening environmental protection and adjusting the primary energy structure. China's rapid economic growth lead to sharp increase in oil imports. Due to China relies on a single chokepoint, the Malacca Strait, which has caused a high degree of concern about the safety of its energy. Nearly three-quarters of its oil imports flowing through the Strait. In view of its strategic importance to China and China’s little sway on the waterway, this view is mainly focused on China’s energy demand and supply in two aspects of concern. The paper analysis of whether the current energy structure is appropriate and sustainable. Because the energy security is facing China's energy is more and more dependent on imported fuel and the need to convert energy to meet the demand of modern society and the rapid growth of the requirements of the economic challenges. Concludes that the China's new policy should focus on energy efficiency, energy saving, renewable energy and turned to the main energy source of natural gas.

Το κύριο θέμα της εργασίας είναι η μοντελοποίηση και η αριθμητική επίλυση μη- μόνιμων και μεταβατικών φαινομένων ροής σε αγωγούς μεταφοράς και δίκτυα διανομής φυσικού αερίου. Το φυσικό αέριο είναι ένα σύγχρονο καύσιμο το οποίο έχει μεγάλες ενεργειακές εφαρμογές καλύπτοντας σε μεγάλο ποσοστό το ενεργειακό ισοζύγιο μιας χώρας. Είναι ένα αέριο και φυσικό καύσιμο για τη μεταφορά του οποίου από τα σημεία άντλησης του, έχει δημιουργηθεί ένα πολύπλοκο διεθνές δίκτυο. Το δίκτυο αυτό συνδέεται με τα εθνικά τοπικά δίκτυα που το διανέμουν στους καταναλωτές. Τα πολύπλοκα αυτά δίκτυα αν και σχεδιάζονται για λειτουργία σε μόνιμη ροή στην πραγματικότητα λειτουργούν υπό μη-μόνιμες συνθήκες. Οι μεταβολές και οι αιχμές στις καταναλώσεις κατά τη διάρκεια μια μέρας, η εκκίνηση ή το κλείσιμο των συμπιεστών ή των σταθμών ρύθμισης της ροής, η αστοχία συσκευών του δικτύου ή και αγωγών είναι μερικοί από τους παράγοντες οι οποίοι προκαλούν σημαντικές μεταβολές στη ροϊκή συμπεριφορά αυτών των συστημάτων. Η υπολογιστική προσομοίωση και η ακριβής πρόβλεψη αυτών των ακραίων ροϊκών καταστάσεων είναι πολύ σημαντική για τη σωστή και οικονομική λειτουργία αυτών των δικτύων. Για την ανάλυση αυτών των φαινομένων η παρούσα εργασία διαρθρώθηκε σε οκτώ κεφάλαια. Στο κεφάλαιο 1 γίνεται ο ορισμός του προβλήματος και η περιγραφή των ροϊκών συνθηκών που διέπουν τα δίκτυα φυσικού αερίου. Στο κεφάλαιο 2 γίνεται εκτεταμένη διερεύνηση στην πρότερη ερευνητική προσπάθεια πάνω σε αυτό το θέμα. Στο κεφάλαιο 3 καταστρώθηκε το μαθηματικό μοντέλο το οποίο προσομοιώνει με επιτυχία τέτοιες ροϊκές καταστάσεις. Εν συνεχεία στα κεφάλαια 4 και 5 αναπτύσσονται αριθμητικές μέθοδοι κατάλληλες για την επίλυση αυτού του μοντέλου. Είναι μέθοδοι κατάλληλες για τον αρχικό σχεδιασμό των αγωγών μεταφοράς (κεφάλαιο 4) όσο και ανώτερης τάξης για πιο ακριβείς υπολογισμούς (κεφάλαιο 5). Στο κεφάλαιο 6 γίνεται η παρουσίαση του αλγόριθμου, για την επέκταση των μεθόδων που αναπτύχθηκαν στα κεφάλαια 4 και 5 για την επίλυση δικτύων πολλών αγωγών και κόμβων. Εν συνεχεία στο κεφάλαιο 7 γίνεται πειραματική διερεύνηση σε εργαστηριακές εγκαταστάσεις αγωγών αερίου που προσομοιώνουν μεταβατικά φαινόμενα ροής. Στο κεφάλαιο 8 γίνεται μια εκτεταμένη επισκόπηση και συγκεντρώνονται τα βασικά συμπεράσματα που προέκυψαν από το σύνολο της ερευνητικής εργασίας. Τέλος γίνονται προτάσεις για την περαιτέρω συνέχιση του ερευνητικού έργου πάνω στο συγκεκριμένο γνωστικό αντικείμενο. / The main subject of the present study is the modelling and the numerical simulation of unsteady and transient flow phenomena in natural gas transmission pipelines and distribution networks. Natural gas is a modern fuel which has serious energy applications covering in big percentage the energy balance of many countries. It is a gas and natural fuel for the transport of which from his points of pumping, has been created a complicated international network. This network is connected with the national local networks that distribute it to local consumers. These complicated networks even if they are designed for operation in steady flow conditions actually work under unsteady conditions. The changes and the peaks of the demand at the duration of a day, the start or the sudden stop of compressors or regulation stations, the failure of network appliances are few of the factors which cause important changes in the flow behaviour of these systems. The simulation and the precise forecast of these extreme flow situations are very important for safe, reliable and economic operation of these networks. For the analysis of these phenomena the present work was structured in eight chapters. In chapter 1 become the definition of problem and the description of flow conditions that rule the natural gas networks. In chapter 2 becomes extensive investigation in the previous research effort on this subject. In chapter 3, the mathematic model which simulates with success such flow situations is defined. Further more in chapters 4 and 5 numerical methods suitable for the numerical solution of this model were developed. These methods are suitable for the initial design of pipelines (chapter 4) as much for more precise calculations (chapter 5). In chapter 6 an improved algorithm for the simulation if complicated networks with many pipes and nodes is presented. The numerical solution of the transient network conditions based on the methodology that developed in previous chapters. In chapter 7 experimental investigations of transient flow phenomena in pipe networks was carried out in laboratory installations. In chapter 8 an extensive review of the basic conclusions was presented, combined with proposals for further research.

In the spring of 1998, a closed end gravity flow pipeline was installed in the Lethbridge Northern Irrigation District. The pipes ranged from 900 mm to 300 mm in diameter. / Manholes were placed at several locations along the pipeline and were used to install velocity meters and pressure transducers, which recorded data every second. Pressures and velocities during periods of steady state were used to calculate the head loss, Re and the Hazen-Williams friction factor, "C", along lengths of constant diameter. / The results were compared to the industry design standard of C = 150 (used for the design of rigid PVC pipe installations) and to the theoretical hydraulically smooth line developed from the Moody diagram and the Darcy-Weisbach equation. Since the maximum and minimum calculated values of C came in the 750 mm and 900 mm diameter pipes, respectively, and all other C values, including those from the 300 mm and 650 mm diameters, fell between these, pipe diameter was assumed not to be a variable. Therefore all the field data was averaged. The average value of Re for the range studied was 9.73 x 105 . The corresponding best-fit C value is 147.7, which is 6.0% lower than the derived theoretical maximum. Since the derived theoretical maximum is the ideal condition and the recorded data was slightly lower and therefore determined be a good representation of what can be expected in true field conditions.

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Natural gas feeds often contain contaminants such as CO₂, H₂S, H₂O, and small hydrocarbons. Carbon dioxide is a major contaminant reducing the heating value of the gas and causing pipeline corrosion, so CO₂ level should be lowered to below 2% to meet the United States pipeline specifications. Membrane separation technology can be advantageous over cryogenic distillation and amine adsorption in terms of cost and efficiency. The key hurdle to overcome in polymeric membrane separation technology is improvement in selectivity, productivity, and durability without introducing significant additional cost. The ultimate goal of this study is to analyze effects due to polymerization conditions and imidization methods on properties of 1,3-propanediol monoesterified crosslinkable polyimide (PDMC). Hillock, Omole, Ward, and Ma did work on PDMC synthesis; however, variability of polymer properties remains a challenge that must be overcome for industrial implementation of PDMC material. First, reaction temperature and reaction time of polymerization prior to imidization were considered as key conditions to affect molecular weight, crosslinkability and transport properties of polymer. Batches with controlled reaction temperature and time were prepared, and properties of each dense film were measured and optimized in terms of permeability, selectivity, and plasticization suppression. Second, imidization methods for PDMC were also studied. There are mainly two kinds of Imidization: chemical Imidization and thermal Imidization. Surprisingly, thermally imidized PDMC showed 70% higher permeability than chemically imidized samples with minimal acrifice in selectivity. At high reaction temperature during the thermal imidization, transamidation can occur. It is believed that the transamidation led to more randomized sequence distribution in the thermally imidized samples. We thus hypothesize that the higher permeability of the thermally imidized PDMC results from greater uniformity of the sequence distribution, as compared to the chemically imidized sample that does not experience high temperature during imidization. XRD, DSC, DMA, and permeation instruments checked and supported this hypothesis. FTIR, TGA, and NMR ruled out the possibility of an alternate hypothesis related to side reaction. Finally, effects of aggressive feed conditions on both chemically imidized PDMC and thermally imidized PDMC dense film were examined. The aggressive feed conditions include high CO₂ partial pressure, operating temperatures, and exposure to high feed pressure. Testing aggressive feed conditions for dense film should be pursued before pursuing hollow fiber applications, to decouple effects on the basic material from those on the more complex asymmetric morphology. This study enables understanding of the disparity between various previous researchers’ selectivity and permeability values. The work shows clearly that polymerization conditions and imidization methods must be specified and controlled to achieve consistently desirable polymer properties. In addition, for batch scale-up and development to a hollow fiber, this fundamental study should enable production of high molecular weight PDMC with good fiber spinnability and defect-free structure.

Steel pipelines are widely used in offshore oil/gas facilities. To achieve economically feasible designs, regulatory codes permit utilization of the pipelines well past their elastic response limit. This requires thorough integrity check of the pipeline subject to large scale yielding (LSY). Engineering criticality assessments (ECA) are used to justify the integrity of a cracked pipeline against fracture failure. The currently used ECA crack driving force equation was developed for load-controlled components subject to very limited crack-tip plasticity. Moreover, fracture toughness data are extracted from deeply-cracked laboratory specimens that produce the lowest margin of toughness values. Therefore, the current framework can be overly conservative (or include non-uniform inaccuracies) for ECA of modern pipelines that undergo LSY and ductile crack growth prior to failure. The two main goals of this thesis are: (i) Development of an alternative crack driving force estimation scheme, (ii) Justification of the use of use of shallow-cracked single edge notch tensile (SENT) specimens for the ECA. Strain concentration in concrete coated pipelines, and effect of Lüders plateau on the fracture response are also investigated. A new reference strain J-estimation scheme is proposed and calibrated to 300 nonlinear parametric FE models, which takes advantage of the linear evolution of the J with LSY bending strains. The scheme is hence strain-based and needless of limit load solutions, providing additional accuracy and robustness. The near-tip stress and strain fields of cracked pipelines were also investigated and compared to those obtained from a K-T type formulation. It is shown that the J-Q constraint theory can satisfactorily characterize these fields up to extreme plastic bending levels. Similar J-Q trajectories were also observed in the SENT and pipeline models. Subsequently, FE models utilizing a voided plasticity material were used to parametrically investigate ductile crack growth and subsequent failure of pipelines subject to a biaxial stress state. Plastic strain and stress triaxiality fields ahead of the propagating crack, along with R-curves, were compared among SENT and pipeline models. It is concluded that the SENT specimen could be a viable option for ECA of such pipes based on the observed crack tip constraint similarity.

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This paper explored the knowledge dynamics of cultural industries in Yogyakarta Region. The aims of this paper are to explain how local knowledge is circulated and how new elements are added, as well as to find out how different kinds of knowledge are anchored. This thesis contributes to fill the gap of the lack of research conducted to explain knowledge dynamics in the context of Indonesian cultural industries. Cultural industries have been increasingly considered important towards economic development, whereas territorial knowledge dynamics (TKD) is considered as an update of the traditional territorial innovation models (TIM). The empirical part of this paper contains data collected from interviews with the representatives of sixteen firms, five government institutions, three local trade associations, one local youth organisation and one non-governmental organisation. The finding reveals that direct observation, face-to-face contact, and local buzz are important towards the circulation of local knowledge within the clusters. Different kinds of innovations were also found, involving multidimensional aspects at micro-levels. In a few cases, innovation was influenced by the presence of global pipelines. Knowledge anchoring happened in a complex process and involved a number of actors in multiple locations and scales. This thesis argues that policy makers should increasingly incorporate the concept of territorial knowledge dynamics (TKD) in the development of Indonesian cultural industries.