A tarefa de regular um mercado estruturado sob a forma de monopólio natural, como no caso da distribuição de gás canalizado no Brasil, implica assegurar o equilíbrio econômicofinanceiro das firmas reguladas, garantindo, ao mesmo tempo, modicidade tarifária e nível de excelência na qualidade dos serviços prestados. Para isso, a questão da formação de preços é crítica, pois envolve aspectos do excedente e sua distribuição. Por esta razão, dentre as atribuições do órgão regulador, destaca-se o estabelecimento de regras tarifárias que conciliem os interesses dos consumidores e da empresa regulada. Entretanto, a tarefa de desenhar tarifas justas é afetada pela assimetria de informações entre o órgão regulador e a firma regulada, em favor da última. Este trabalho sugere a incorporação da metodologia do Economic Value Added EVA® no processo de revisão tarifária. Tal incorporação, conforme demonstrado, permite ao regulador avaliar a geração de valor do setor e reduzir a assimetria informacional entre concessionárias e agência reguladora. Além disso, facilita o repasse de eventuais excessos de geração de valor aos consumidores, em benefício da sociedade. Palavras-chaves: Assimetria de informação, Economic value added (EVA®), gás canalizado, gás natural, geração de valor, revisão tarifária. / Regulating a structured market under natural monopoly such as the Brazilian pipeline gas distribution implies in assuring an economic and financial equilibrium of the regulated firms as well as guaranteeing the tariff moderateness and service quality excellence. In order to achieve this pricing is crucial, for it encompasses surplus and surplus distribution. Therefore, the role of setting tariff rules of the regulator agency, stands out so that these rules conciliate the interests of both consumers and the regulated companies. However, outlining fair tariffs is impacted by asymmetrical information between regulator agency and regulated firms in favor of the latter. This study suggests incorporating the Economic Value Added methodology in tariff revision process. This incorporation allows the regulator to evaluate the value generation in the sector and to reduce asymmetrical information between companies regulated and the regulator. In addition to this, it makes it easier to allocate the possible value generation surplus to the consumers in favor of the society. Key words: Asymmetrical information, economics regulation, tariff revision, value generation, economic value added (EVA®), natural gas, and pipeline gas.

Thesis. 1975. M.S.--Massachusetts Institute of Technology. Dept. of Chemical Engineering. / Bibliography: leaves 63-65. / M.S.

Thesis. 1978. Sc.D.--Massachusetts Institute of Technology. Dept. of Chemical Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Vita. / Bibliography: leaves 421-426. / by Jaime A. Valencia-Chávez. / Sc.D.

The introduction of alternative fuels such as natural gas is likely to occur at an increasing rate. The dual-fuel concept allows these low cetane number fuels to be used in compression-ignition (CI, diesel) type engines. Most CI engine conversions have pre-mixed the alternative fuel with air in the intake manifold while retaining diesel injection into the cylinder for ignition. The advantage is that it is simple for practical adaptation; the disadvantage is that good substitution levels are only obtained at midload. A better solution is to inject both the alternative and diesel fuels directly into the cylinder. Here, the fuel in the end-zone is limited and the diesel, injected before the alternative, has only a conventional ignition delay. This improves the high-end performance. Modern, very high pressure diesel injectors have good turndown characteristics as well as better controllability. This improves low-end performance and hence offers an ideal platform for a dual-fuel system. Several systems already exist, mainly for large marine engines but also a few for smaller, truck-sized engines. For the latter, the key is to produce a combined injector to handle both fuels which has the smallest diameter possible so that installation is readily achieved. There exists the potential for much improvement. A combined gas/diesel injection system based on small, high pressure common-rail injectors has been tested for fluid characteristics. Spray properties have been examined experimentally in a test rig and modelled using CFD. The CFD package Fluent was used to model the direct-injection of natural gas and diesel oil simultaneously into an engine. These models were initially calibrated using high-speed photographic visualisation of the jets. Both shadowgraph and schlieren techniques were employed to identify the gas jet itself as well as mixing regions within the flow. Different orientations and staging of the jets with respect to each other were simulated. Salient features of the two fuel jets were studied to optimise the design of a dual-fuel injector for CI engines. Analysis of the fuel-air mixture strength during the injection allowed the ignition delay to be estimated and thus the best staging of the jets to be determined.

As drilling for natural gas in the Marcellus Shale becomes increasingly prevalent, both human safety and environmental concerns have arisen. The aim of this study was to assemble an environmental baseline to make an accurate assessment of its possible impacts. Water samples and chemical parameters were collected from Bates Fork, a stream with Marcellus Shale drilling activity and Fonner Run, a sister stream with no drilling activity, on a monthly basis beginning in the summer of 2010. Bacterial DNA was also extracted from water collected at each site and then amplified using primers for the variable ribosomal internal transcribed spacer (ITS) region of 16S and 23S rRNA. The bacterial ribosomal ITS has both sequence and length variability, which can be used to approximate species abundance and diversity along both streams. The conserved 16S rRNA gene was also amplified, and sequenced to taxonomically categorize organisms. To date, it has been observed that Bates Fork has consistently higher conductivity and chloride levels than Fonner Run. The bacterial diversity was found to be similar between the two streams. As a baseline study, these results show that there have not been any detectable impacts to Bates Fork thus far, but the stream should continue to be monitored. / Bayer School of Natural and Environmental Sciences / Biological Sciences / MS / Thesis

Le développement et l'utilisation des procédés industriels à basse température ont été très importants durant ces dernières années. Le développement est surtout dû à l'accroissement de la demande en produits liquides (purs ou mélanges) sur le marché mondial. L'auteur de cette thèse propose une analyse approfondie des trois grandes familles de procédés de liquéfaction du gaz naturel utilisés en Algérie. Il commence par examiner les traitements subis par le gaz naturel avant sa liquéfaction qui consiste à le ramener à une température de -160°C et à une pression légèrement supérieure à la pression atmosphérique. Il analyse ensuite, à l'aide du logiciel ASPEN PLUS, les différentes performances des trois types de cycles et conclut en montrant que le cycle Propane-MCR est thermodynamiquement le plus avantageux.

We have developed a new automatic apparatus for the measurement of the phase equilibrium and pVT properties of natural gas mixtures in our laboratory. Based on the isochoric method, the apparatus can operate at temperature from 200 K to 500 K at pressures up to 35 MPa, and yield absolute results in fully automated operation. Temperature measurements are accurate to 10 mK and pressure measurements are accurate to 0.002 MPa. The isochoric method utilizes pressure versus temperature measurements along an isomole and detects phase boundaries by locating the change in the slope of the isochores. The experimental data from four gas samples show that cubic equations of state, such as Peng-Robinson and Soave-Redich-Kwong have 1-20% errors in predicting hydrocarbon mixture dew points. The data also show that the AGA 8-DC92 equation of state has errors as large as 0.6% when predicting hydrocarbon mixture densities when its normal composition range is extrapolated.

Le développement et l'utilisation des procédés industriels à basse température ont été très importants durant ces dernières années. Le développement est surtout dû à l'accroissement de la demande en produits liquides (purs ou mélanges) sur le marché mondial. L'auteur de cette thèse propose une analyse approfondie des trois grandes familles de procédés de liquéfaction du gaz naturel utilisés en Algérie. Il commence par examiner les traitements subis par le gaz naturel avant sa liquéfaction qui consiste à le ramener à une température de -160°C et à une pression légèrement supérieure à la pression atmosphérique. Il analyse ensuite, à l'aide du logiciel ASPEN PLUS, les différentes performances des trois types de cycles et conclut en montrant que le cycle Propane-MCR est thermodynamiquement le plus avantageux.

Petrophysical evaluation of the Albian age gas bearing sandstone reservoirs of the O-M field, Offshore South Africa has been performed. The main goal of the thesis is to evaluate the reservoir potentials of the field through the integration and comparison of results from core analysis, production data and petrography studies for the evaluation and correction of key petrophysical parameters from wireline logs which could be used to generate an effective reservoir model. A total of ten wells were evaluated and twenty eight sandstone reservoirs were encountered of which twenty four are gas bearing and four are wet within the Albian age depth interval of 2800m to 3500m. Six lithofacies (A1, A2, A3, A4, A5 and A6) were grouped according to textural and structural features and grain size from the key wells (OP1, OP2 and OP3). Facies A6 was identified as non reservoir rock in terms of reservoir rock quality and facies A1 and A2 were regarded as the best reservoir rock quality. This study identifies the different rock types that comprise reservoir and non reservoirs. Porosity and permeability are the key parameters for identifying the rock types and reservoir characterization.

Historically, Ukraine has been a net energy importer, needing oil and natural gas for the effective functioning of its industries and satisfaction of domestic needs. Ukraine's independence immediately followed the disintegration of the Soviet Union in 1991, resulting in its ultimate dependency on oil and natural gas imports from Russia. During the last few years, the parties had undergone a number of disagreements that led to the disruption of natural gas supply to Ukraine, and political instability within the country. The necessity to redevelop Ukraine's domestic energy industry and adjust it to an available domestic natural gas source became vitally important for the national government. The present project provides a summary of the Ukrainian energy policy dynamics from 2006-present time. It specifies current energy trends, renewable energy sources, alternatives, and provides recommendations for the Ukrainian government on how to integrate successful international experiences into the development of coalbed methane in the local environment. / McAnulty College and Graduate School of Liberal Arts; / Graduate Center for Social and Public Policy / MA; / Thesis;