Multiphase flows occurring in pipelines with a serpentine configuration is an important phenomenon, which can be encountered in heat exchangers used in a variety of industrial processes. More specifically, in many industrial units such as a large cracking furnace in a refinery, the tubes are arranged in a serpentine manner and are relatively short. As flow negotiates round the 180o bend at the ends of the tubes, the generated centrifugal force could cause flow maldistribution creating local dry spots, where no steady liquid film is formed on the adjacent straight sections of the pipe. As a result, events including coking, cracking and overheating of heat transfer surfaces may occur and lead to frequent shutdown of the facilities. Consequently, this could increase operating costs and reduce production revenue. Thus, it is desirable to know the effect that the bends exert on the flow in the straight part of the pipe. Apart from this, knowledge of the bend effects on the flows in the pipeline could also be important for the design of other pipelines for gas/liquid transport, e.g. offshore gas and oil pipelines. Quite a large number of studies have been found in the literature. The majority of them were for two-phase flow with small diameter pipes (i.d. ≤ 50 mm). However, studies with large diameter pipes (i.d. ≥ 100 mm), have increasingly been considered in recent years as problems related to large diameter vertical pipes are being encountered more and more often in industrial situations. This thesis studies the effect of 180o bends on the characteristics and development of gas-liquid two-phase flows in large diameter downward and upward pipes. The study particularly focuses on the influence of serpentine configuration on flow structure, cross-sectional void distribution and circumferential liquid film profiles and their development along the downward and upward sections. It was found that both the top and bottom bends have considerable impacts on flow behaviour, although to varying degrees. These impacts were highly dependent on the air and water flow rates. For sufficient flow rates, the bends were observed to create flow maldistribution in the adjacent straight section, due to the effects of centrifugal force. The air moved towards the inner zone of the bend and the water towards the outer zone, while a lesser quantity of water was identified on the other surfaces of the pipe. Investigation of the film thickness development in the downward and upward sections showed that, the liquid film behaviour close to the bends was significantly different from those located further away. This can be attributed to the centrifugal force of the bends. Examination of the power spectral density (PSD) along the downward and upward sections showed that, the shape of PSD located in the adjacent section to the bends, was substantially different from those located further away. Furthermore, several flow regime maps were generated which showed that, in addition to bubbly, intermittent and annular flows, unstable flows existed along the upward section, particularly for low gas and water flow rates. In this study it was found that, the lower bend was periodically blocked by the liquid and then blown through by the accumulated air. The data obtained from this study were compared with different theoretical correlations found in the existing literature. Some discrepancy between the results of the current study and those of previous published materials was noted. Updated correlations were presented which provided well results when they applied for the data obtained from the current study and previous studies.

O objetivo deste trabalho consiste em analisar as implicações das regras sociais implícitas brasileiras no desenvolvimento sócio-econômico do país sob a luz da teoria neoinstitucionalista. Inserido neste arcabouço teórico tem-se um desenvolvimento alcançado a partir de um progressivo ajustamento entre as instituições e a realidade. Como realidade, entende-se, neste estudo, o capitalismo. Desta forma, primeiramente, se analisa as instituições que propiciaram o surgimento do capitalismo na Europa, enfatizando as revoluções precedentes que influenciaram a formação sócio-cultural deste sistema. Posteriormente, se realiza um resgate histórico da formação sócio-econômica do Brasil destacando os aspectos culturais enraizados na sociedade durante o período colonial. Observa-se que, a despeito da industrialização, o Brasil permaneceu calcado em valores tradicionais e arcaicos que não condizem com os valores modernos da gênese do capitalismo. Tendo em vista estes conceitos, utiliza-se do Reconstitutive Downward Causation para se analisar a forma em que emergem as instituições no Brasil. Observou-se que, enquanto as instituições que operam no ambiente informal surgem a partir dos hábitos mentais dos próprios indivíduos, as instituições que operam no âmbito formal são decorrentes da importação de modelos externos. Esta incoerência faz com que surja o ‘jeitinho brasileiro’, uma instituição que permite ao indivíduo lidar com a esfera formal mantendo seus hábitos mentais. / The objective of this study consists of analyzing the implications of the Brazilian implicit social rules in the socio-economic development of the country under the light of neoinstitutionalist theory. Inserted in this theoretical approach, development it is achieved from a gradual adjustment between institutions and reality. As, reality, it is understood in this study, capitalism. Thus, first, examines the institutions that enabled the emergence of capitalism in Europe, emphasizing the previous revolutions that have influenced the social-cultural formation of the system. Subsequently, it is done a rescue of the historic socio-economic formation of Brazil highlighting the cultural aspects rooted in society during the colonial period. It is observed that, in spite of industrializations, Brazil remained based on traditional and archaic values which do not match with the values of the genesis of modern capitalism. In view of these concepts, the Reconstitutive Downward Causation concept it is used to examine the way in which institutions emerge in Brazil. It was observed that while the institutions operating in the informal environment arise from the mental habits of the individual themselves, the institutions that operate under formal scope are resulted from the importation of foreign models. This inconsistency makes it arises the ‘jeitinho brasileiro’, an institution that allows the individual to deal with formal sphere keeping its mental habits.

O objetivo deste trabalho consiste em analisar as implicações das regras sociais implícitas brasileiras no desenvolvimento sócio-econômico do país sob a luz da teoria neoinstitucionalista. Inserido neste arcabouço teórico tem-se um desenvolvimento alcançado a partir de um progressivo ajustamento entre as instituições e a realidade. Como realidade, entende-se, neste estudo, o capitalismo. Desta forma, primeiramente, se analisa as instituições que propiciaram o surgimento do capitalismo na Europa, enfatizando as revoluções precedentes que influenciaram a formação sócio-cultural deste sistema. Posteriormente, se realiza um resgate histórico da formação sócio-econômica do Brasil destacando os aspectos culturais enraizados na sociedade durante o período colonial. Observa-se que, a despeito da industrialização, o Brasil permaneceu calcado em valores tradicionais e arcaicos que não condizem com os valores modernos da gênese do capitalismo. Tendo em vista estes conceitos, utiliza-se do Reconstitutive Downward Causation para se analisar a forma em que emergem as instituições no Brasil. Observou-se que, enquanto as instituições que operam no ambiente informal surgem a partir dos hábitos mentais dos próprios indivíduos, as instituições que operam no âmbito formal são decorrentes da importação de modelos externos. Esta incoerência faz com que surja o ‘jeitinho brasileiro’, uma instituição que permite ao indivíduo lidar com a esfera formal mantendo seus hábitos mentais. / The objective of this study consists of analyzing the implications of the Brazilian implicit social rules in the socio-economic development of the country under the light of neoinstitutionalist theory. Inserted in this theoretical approach, development it is achieved from a gradual adjustment between institutions and reality. As, reality, it is understood in this study, capitalism. Thus, first, examines the institutions that enabled the emergence of capitalism in Europe, emphasizing the previous revolutions that have influenced the social-cultural formation of the system. Subsequently, it is done a rescue of the historic socio-economic formation of Brazil highlighting the cultural aspects rooted in society during the colonial period. It is observed that, in spite of industrializations, Brazil remained based on traditional and archaic values which do not match with the values of the genesis of modern capitalism. In view of these concepts, the Reconstitutive Downward Causation concept it is used to examine the way in which institutions emerge in Brazil. It was observed that while the institutions operating in the informal environment arise from the mental habits of the individual themselves, the institutions that operate under formal scope are resulted from the importation of foreign models. This inconsistency makes it arises the ‘jeitinho brasileiro’, an institution that allows the individual to deal with formal sphere keeping its mental habits.

abstract: Contemporary research has examined the relationship between determinate sentencing reforms and unwarranted punishment disparities in states and the federal criminal justice system. Recent investigations suggest that legal developments in federal sentencing—namely, the High Court’s rulings in U.S. v. Booker (2005) and Gall/Kimbrough v. U.S. (2007) which rendered and subsequently reaffirmed the federal guidelines as advisory—have not altered disparities associated with imprisonment outcomes. Punishment disparities following Booker and Gall, particularly racial and ethnic disparities, have been linked to Assistant U.S. Attorneys’ (AUSAs) use of substantial assistance departures. What remains unanswered in the literature is whether the changes in AUSAs’ decision making following the landmark cases has enduring effects and whether the effects are conditioned by defendants’ race/ethnicity and the type of case (guidelines cases or mandatory minimum cases), and whether the use of substantial assistance varies across U.S. District Courts. Accordingly, these questions are examined using sentencing data from the U.S. Sentencing Commission, coupled with data from the National Judicial Center, U.S. Census Bureau, Uniform Crime Reports, and Interuniversity Consortium for Political and Social Research. This study looks at 465,476 defendants convicted from fiscal year 2001 to fiscal year 2010 across 89 federal districts. A series of multilevel discontinuity regression models are estimated to assess the short-term and long-term effects of the Booker and Gall/Kimbrough decisions on AUSAs’ use of substantial assistance departures, accounting for contextual differences between federal district courts. The results show that AUSAs are less likely to seek motions for substantial assistance immediately and in the long term in the post-Booker period but are more likely to seek substantial assistance in the long term in the post-Gall/Kimbrough period. These effects, however, are restricted to the models that include all cases and guidelines cases. The interaction models show that Hispanic defendants facing a mandatory minimum sentence are less likely to receive a substantial assistance departure immediately and in the long term following the Court’s Booker decision. Moreover, the use of substantial assistance varies across federal districts. The results are discussed in relation to their implications for theory, courts and sentencing policy, and future research on punishment outcomes. / Dissertation/Thesis / Doctoral Dissertation Criminology and Criminal Justice 2015

abstract: Firms reduce investment when facing downward wage rigidity (DWR), the inability or unwillingness to adjust wages downward. I construct DWR measures and exploit staggered state-level changes in minimum wage laws as an exogenous variation in DWR to document this fact. Following a minimum wage increase, firms reduce their investment rate by 1.17 percentage points. Surprisingly, this labor market friction enhances firm value and production efficiency when firms are subject to other frictions causing overinvestment, consistent with the theory of second best. Finally, I identify increased operating leverage and aggravation of debt overhang as mechanisms by which DWR impedes investment. / Dissertation/Thesis / Doctoral Dissertation Business Administration 2017

O regime de meta para a inflação foi adotado por um amplo conjunto de países nos últimos anos. Evidentemente, a definição da meta de inflação a ser perseguida é parte essencial do regime. O presente trabalho pretende contribuir para o debate sobre a meta ótima para o Brasil. O trabalho está dividido em três ensaios que, por caminhos diversos, buscam estimar quantitativamente os custos e benefícios de diferentes metas de inflação para a economia brasileira. O foco é sobre os efeitos de longo prazo de diferentes metas, uma vez que esses são mais relevantes do que os possíveis custos de ajustamento para uma eventual nova meta de inflação. O primeiro artigo aborda a questão sobre a meta de inflação ótima para o Brasil por meio da perda de bem estar medida pela demanda de moeda, um canal clássico considerado pela literatura. O segundo avalia a relação entre o nível e a incerteza sobre a inflação futura, utilizando para tanto modelos para a estimação da variância condicional da inflação, as expectativas de inflação relatadas por analistas econômicos e medidas de inflação implícita em preços de ativos. O terceiro artigo apresenta um enfoque mais teórico e estrutural, apresentando um modelo no qual existe um trade-off para a meta de inflação e calibrando esse modelo para obter estimativas da meta ótima para a economia brasileira. O modelo considera, de um lado, a perda de bem estar causada pela inflação através da demanda de moeda e, de outro, o benefício pela redução da perda de eficiência econômica ocasionada pela rigidez dos salários nominais. Concluímos que a análise exposta no presente trabalho sugere que, tendo em vista a redução da incerteza macroeconômica na economia brasileira nos últimos anos, haveria motivos também para uma redução gradual da meta de inflação. Contudo, também aponta que não se deve buscar metas muito baixas, uma vez que o benefício adicional em se reduzir a meta de inflação é relativamente pequeno quando já se está em um nível de inflação baixo. / Inflation targeting regimes have been adopted by a large number of countries in recent years. Obviously, the definition of the actual inflation target to be pursued is an essential part of this regime. This work aims to make a contribution to the debate about the optimal target for Brazil. The three essays follow different paths in an attempt to estimate the quantitative costs and benefits of the different inflation targets for the Brazilian economy. The focus is on the long-term effects of the different targets as these are more important than the possible costs during the transition towards the new inflation target. The first article discusses the optimal inflation target based on the welfare loss measured by the money demand function, a classic channel highlighted in the literature. The second assesses the relation between the level and uncertainty of future inflation. We investigate this issue with the use of econometric models to estimate the conditional variance of inflation, of inflation expectations reported by professional economic analysts and of break-even inflation rates. The third article presents a more theoretical and structural focus. We present a model in which there is a trade-off for the inflation target and this model is calibrated to obtain estimates of the optimal target for the Brazilian economy. On one hand, the model considers the welfare loss caused by inflation through money demand and, on the other, the benefit from the reduced frequency of periods in which a downward nominal wage restriction binds. Our conclusion is that the analysis presented suggests that, considering the lower macroeconomic uncertainty observed in Brazil in the recent years, there would be reasons for a gradual reduction in the inflation target. However, it also suggests that very low targets should not be set as the additional benefit in reducing the inflation target is relatively small once the inflation target has already been set at a low level.

The present dissertation explores the Congolese immigrant workers‟ meanings, their labour migration and their transnationalism in Pretoria through the perspective of south-south social transformation. It argues that this migration is partly an outcome and effect of various social transformations that have been occurring in Southern Africa since the end of cold war in the era of globalisation and age of mass migration. The study draws on Castles‟ middle range theory and the comprehensive sociology of Max Weber. This dissertation makes use of qualitative method, based on ethnography, and corresponding techniques such as interviews. The study shows that what drives Congolese labour migration to Pretoria are economic (wage differential or cost benefit), political issues (wars, violence against human rights, freedom of speech), cultural (the Congolese mythology of migration) and psychological reasons (prestige). These migration processes and patterns are also determined by migrants‟ social class position in the DRC. The latter to a large extent determines the nature and status of their employment in Pretoria. In addition, findings demonstrate that a number of structural constraints and features of Congolese qualifications, skills, and even culture contribute to Congolese immigrants negative performances in the South African labour market. Faced with numerous barriers to professional incorporation, Congolese migrants resort to any legal or illegal means to bypass these barriers. It is revealed that the Congolese conception of social and occupational mobility is mostly understood in terms of economic or income mobility. This dovetails with the socially constructed meanings that Congolese workers attach to their work. Concerning their transnational activities, research participants are shown to be involved in political, economic and socio-cultural activities. Most of their activities are nationally-oriented. Nevertheless, the weight of the tense political situation has an influence on their transnational activities and Congolese culture and/or homeland politics leads to their economic transnationalism. For these reasons, practices of remitting are connected with transnational political activities and culture. Despite the extensive contacts „back home‟ socio-cultural activities of the Congolese in Pretoria are marked by cultural hybridization between Congolese migrants and South Africans. / Dissertation (MSocSci)--University of Pretoria, 2014. / lk2014 / Sociology / MSocSci / Unrestricted

Climate change is expected to increase the frequency, intensity and duration of droughts in all parts of the United States (US). Snow packs are disappearing earlier in the spring and summer, with reduced stream-flow. Lower reservoir levels, higher temperatures, and greater precipitation variability have been observed. Drought events in the US have threatened drinking water supplies for communities in Maryland and Chesapeake Bay as observed in 2001 through September 2002; Lake Mead in Las Vegas in 2000 through 2004; Peace River and Lake Okeechobee in South Florida in 2006; and Lake Lanier in Atlanta, Georgia in 2007. ENSO influences the climate of Florida; where El Niño years tend to be cooler and wetter, while La Niña years tend to be warmer and drier than normal in the fall through the spring, with the strongest effect in the winter. Both prolonged heavy rainfall and drought potentially have impacts on land uses and many aspects of Florida's economy and quality of life. Drought indices could integrate various hydrological and meteorological parameters and quantify climate anomalies in terms of intensity, duration, and spatial extent, thus making it easier to communicate information to diverse users. Hence, understanding local ENSO patterns on regional scales and developing a new land use drought index in Florida are critical in agriculture and water resources planning and managements. Current drought indices have limitations and drawbacks such as calculation using climate data from meteorological stations, which are point measurements. In addition, weather stations are scarce in remote areas and are not uniformly distributed. Currently used drought indices like the iv PDSI and the Standardized Precipitation Index (SPI) could not fully demonstrate the land use effects. Other limitations include no single index that addresses universal drought impact. Hence, there is a renewed interest to develop a new “Regional Land Use Drought Index (RLDI) that could be applied for various land use areas and serve for short term water resources planning. In this study, the first and second research topics investigated water and energy budgets on the specific and important land use areas (urban, forest, agriculture and lake) in the State of Florida by using the North American Regional Reanalysis (NARR) reanalysis data. NARR data were used to understand how drought events, EI Niño, La Niña, and seasonal and inter-annual variations in climatic variables affect the hydrologic and energy cycle over different land use areas. The results showed that the NARR data could provide valuable, independent analysis of the water and energy budgets for various land uses in Florida. Finally, the high resolution land use (32km×32km) adapted drought indices were developed based on the NARR data from 1979 to 2002. The new regional land use drought indices were developed from normalized Bowen ratio and the results showed that they could reflect not only the level of severity in drought events resulting from land use effects, but also La Niña driven drought impacts.

No description available.

This dissertation studies the reaction of trading behavior of investors, especially institutional investors, to the public information in Taiwan. Two kinds of public information are chosen in this dissertation. One is open-ending closed-end funds under the regulation set up by Taiwan authority. The other is the change of stocks in MSCI Taiwan Index that is decided by Morgan Stanley Capital International (MSCI), a well-known foreign institution in constructing various indices. Consistent with earlier studies using U.S. data, our results show that open-ending is a wealth-enhancing event for shareholders. We also provide evidence of the existence of noise traders in the closed-end fund market. The evidence is derived from the trading behavior of domestic institutional investors and small individual investors, who ignore price discounts when open-ending is imminent. The trading by noise traders impedes price adjustments to the discounts, and provides profit opportunities to arbitragers. Furthermore, we show that foreign investors gain considerable wealth, largely at the expense of domestic institutional investors and small individual investors, in the open-ending process. On average, their gains account for 30% of the total gains associated with open-ending, or NT$562 millions per case. On the issue of the change of stocks in MSCI Taiwan Index, we find that MSCI prefers to select the securities with good performance, high liquidity, and large firm size into MSCI Taiwan Index while tends to drop the securities with poor performance, lower liquidity, and small firm size from MSCI Taiwan Index. Besides, consistent with the previous studies, prices increase (decrease) significantly for stocks added to (deleted from) the MSCI Taiwan Index after the announcement date. As well as the deletions, the price decreases for unchanging stocks after the announcement date. However, there is no evidence to find that foreign investors have information advantage in MSCI news over domestic investors. Foreign investors increase (decrease) their holdings on stocks included in (excluded from) the MSCI Taiwan Index after the announcement date. Moreover, price pressure hypothesis is not supported. Visibility hypothesis, information content hypothesis, downward sloping demand curves hypothesis are supported. Finally, for additions and deletions, the market-adjusted returns are driven by the contemporaneous excess buy of foreign investors and the contemporaneous excess sells of domestic corporations and individuals.