Orientadores: Florencia Cecilia Menegalli, Maria Isabel Rodrigues / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-24T08:01:10Z (GMT). No. of bitstreams: 1 Vissotto_FernandaZaratini_D.pdf: 6786611 bytes, checksum: dffef14262649a8cbe2a7daad1cf4d46 (MD5) Previous issue date: 2014 / Resumo: Os achocolatados em pó são formulados com a mistura de cacau, açúcar, maltodextrina e aromas, podendo conter derivados lácteos. Para se obter uma adequada reconstituição em líquidos, os achocolatados são submetidos aos processos de lecitinação (adição de um agente tensoativo: lecitina de soja) e aglomeração com vapor. Um dos objetivos desse estudo foi o de avaliar os efeitos das variáveis do processo de aglomeração com vapor (pressão do vapor, temperatura do secador rotativo, vazão de sólidos da alimentação e frequência de rotação do secador) sobre as características físicas e físico-químicas de achocolatados em pó. A aglomeração com vapor levou a um aumento do diâmetro médio de partículas, sendo mais pronunciado no produto formulado com o açúcar moído. O processo foi responsável pelo escurecimento e redução da umidade dos achocolatados, além da diminuição dos tempos de molhabilidade. Adicionalmente foi caracterizada a morfologia dos grânulos de achocolatado, obtidos em diferentes condições operacionais do aglomerador (máxima, média e mínima), utilizando os descritores de tamanho e forma. Os resultados mostraram que não existe diferença entre os descritores de forma e quanto aos descritores de tamanho verificou-se diferença entre as condições de processo para grânulos maiores que 600 ?m. Concluiu-se que os grânulos de achocolatado aglomerados apresentaram formato alongado. Foram também determinadas as transições de fase e as temperaturas de transição vítrea (Tg) de achocolatados em pó e dos seus principais constituintes. Durante a aglomeração com vapor a alta temperatura levou o açúcar moído a uma condição acima da sua Tg, passando a ser esse componente um veículo para a granulação. A Tg da maltodextrina é pequena em atividades de água elevadas (Tg= - 4,9 °C; Aa= 0,843), o que também a torna um veículo para o processo de aglomeração. No cacau em pó alcalino foi observada a fusão da manteiga de cacau (aparecimento das formas polimórficas ?v e ?). Para o achocolatado lecitinado verificou-se que a Tg aumenta com o incremento da atividade de água do meio, portanto para esse tipo de produto a água, ao ser adsorvida, não consegue interagir com o material, não sendo verificado o efeito plasticizante. Para o achocolatado aglomerado com vapor verificou-se que a Tg diminuiu com o aumento da atividade de água do meio (efeito plasticizante). A evolução do caking dos constituintes dos achocolatados mostrou que o cacau em pó apresentou baixa higroscopicidade (pequeno aumento do ângulo de repouso com o tempo), pequena formação de aglomerados e a ausência do caking. A medida da força de compressão dos agregados formados mostrou que a sacarose formou pontes mais rígidas entre as partículas que a maltodextrina. Foi também monitorada a estabilidade de achocolatados em pó lecitinados e aglomerados com vapor, estocados a 25 e 35 °C, numa umidade relativa de 84%, buscando-se simular um clima quente e úmido (região norte do Brasil). Ao longo do tempo, verificou-se aumento do ângulo de repouso e escurecimento dos produtos. O achocolatado lecitinado mostrou-se mais susceptível ao empedramento que o aglomerado, com a formação de grumos a partir do 63° dia de armazenamento / Abstract: Cocoa beverage powders consist of a mixture of cocoa, sugar, maltodextrin, flavors, and may contain dairy products. To obtain products with adequate reconstitution in liquids, the cocoa beverage powders are subjected to the processes of lecithination (addition of the surfactant soy lecithin) and steam agglomeration. One objective of this study was to evaluate the effects of the main variables of the steam agglomeration process (vapor pressure, temperature of rotary dryer, solid feed rate and dryer rotation frequency) on the physical and physicochemical characteristics of cocoa beverage powders. The steam agglomeration led to an increased average particle diameter, being more pronounced in the product formulated with granulated sugar. The process was responsible for powder darkening, reduction of the product¿s moisture and decrease in the wettability. Additionally, the morphology of the cocoa beverage powder granules was characterized in different operating conditions of the steam agglomerator (maximum, average and minimum) using the descriptors of size and shape. There were no differences between the shape descriptors and as to the size descriptors there were differences in the process conditions studied for the granules of size above 600 ?m. It was observed that the steam agglomerated cocoa beverage granules had a more elongated shape. It was also determined phase transitions and the glass transition temperature (Tg) of cocoa beverage powders and the main constituents of these products. During the steam agglomeration, the high temperature led the granulate sugar to a condition above its Tg, making this ingredient a granulation vehicle. The Tg of maltodextrin is small at higher water activities (Tg = - 4.9 °C, aw = 0.843), which makes this ingredient a vehicle for the agglomeration process. For the alkaline cocoa powder the phase transition observed is the melting of the cocoa butter with the appearance of polymorphic forms ? and ?v. For the lecithinated cocoa beverage powder, it was verified that the Tg increases with the increasing of the water activity, which leads to the conclusion that for this type of product the adsorbed water cannot interact with the material, and the plasticizing effect is not noted. For the steam agglomerated cocoa beverage powder it was observed that the Tg decreases with increasing water activity (plasticizing effect). The evolution of the caking for the constituents of cocoa beverage powders showed that the cocoa powder had low hygroscopicity (small increase of the repose angle with time), little formation of granules and the absence of caking. The measurement of the compression strength of the aggregates showed that sucrose formed bridges more rigid between the particles than maltodextrin. Stability of lecithinated and steam agglomerated cocoa beverage powders stored at 25 and 35 °C, in a relative humidity of 84%,was also monitored, in order to simulate hot and humid climates (like northern Brazil). Overtime, it was observed increase of the repose angles and products darkening. The lecithinated cocoa beverage powder was more susceptible to caking than the steam agglomerated product, with the formation of lumps from the 63th day of storage / Doutorado / Engenharia de Alimentos / Doutora em Engenharia de Alimentos

Thesis advisor: Arthur Lewbel / In my dissertation I studied the political economy of economic development as well as the the urban wage premium, all using data from Brazil. In the first chapter, which is joint work with Carlos Varjao, we analyze the effect that increased political opposition in the city council has on corruption and public service provision at the local level. In the second chapter I study the sources of the high wage premium observed in cities, including firm sorting, firm and occupational matching, and compensating wage differentials. Finally, in the third chapter I study what happens to the provision of public education when a school teacher is elected to the city council (which actually occurs quite frequently). More detailed summaries of each chapter follow below. Chapter 1: In 'Political Opposition, Legislative Oversight, and the Performance of the Executive Branch', we study the effect that increased political opposition has on corruption and other measures of the mayor's performance in Brazil. The separation of powers between the executive and legislative branches is a cornerstone of democracy. This system of checks and balances, however, can be circumvented by partisan loyalties if legislators strategically avoid exerting oversight when their own party controls the executive branch. It is thus an empirical question whether the separation of powers prevents the abuse of power in practice. We answer this question by measuring the extent to which members of political opposition parties in a city council effectively check the mayor's performance in Brazil. We employ a regression discontinuity design to estimate the causal effect of an additional politically opposed legislator, and we find that political opposition increases oversight action and decreases corruption, with the effect fully concentrated on mayors facing reelection pressure. We trace the impact of oversight, via a reduction in healthcare spending irregularities, all the way to impacts on healthcare service delivery and health outcomes. Chapter 2: In 'Decomposing the Urban Wage Premium in Brazil: Firms, Matching, and Compensating Wage Differentials' I study the sources of the high wage premium observed in cities. In this chapter I used detailed employer-employee matched data from Brazil to understand 3 important elements of the urban wage premium: (1) the role of firms sorting into cities, (2) the role of firm and occupational matching in creating agglomeration economies, and (3) the role of compensating wage differentials. I first exploit identification from multi-city firms to show that positive selection of high-wage firms into larger cities accounts for 44% of what is often considered `agglomeration economies'. Then I show that improved firm and occupational matching together account for 87% of agglomeration effects. I then turn my attention to compensating wage differentials--- a possible explanation for the high-wage firms in cities. I estimate revealed-preference valuation of jobs, and show that jobs in cities in fact have better non-wage characteristics, and so high urban wages cannot be due to compensating wage differentials. This evidence together suggests that in Brazil, cities exist because they provide thick labor markets where high-wage firms and high-wage workers can go to find productive matches. Chapter 3: In 'Teachers in Politics: Teacher-Politicians, Gender, and the Representation of Public Education' I study what happens to public education in a city when a school teacher is elected to the city council, and I find that it depends on the gender of the teacher. Using a regression discontinuity design that exploits close elections, I find that when a female teacher is elected to the city council, the city hires both more teachers and more qualified teachers, and pays them more. Having a female teacher on the city council also increases the likelihood that the city's schools have necessary teaching resources, books, and financing, and possibly increases student test scores. No significant effect is found for male teachers elected to the city council. This difference may be due to different political career concerns for men versus women, a simple amplification of existing gender policy preference differences, or some mixture of the two. / Thesis (PhD) — Boston College, 2021. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.

In the midst of global economic and financial integration, there are increasing cross-border capital flows between China and the rest of the world. Foreign financial businesses also start to play more important roles in the nation's market after waves of financial reforms. Within such a background, this study aims to investigate the agglomeration and location choice of overseas financial institutions in Chinese cities. Data from the 2004 China Economic Census show that foreign financial establishments, including banks, insurance companies, and other financial service businesses, were mainly agglomerated in coastal cities. In particular, three major urban areas, Shanghai, Beijing, and Guangzhou, concentrated a majority of overseas financial institutions. Results from regression models show that foreign businesses' location choice is greatly influenced by a city's urban economy, involvement in the global market, and telecommunication infrastructure. However, we do not find a significant link between foreign financial institutions' market entry and the size of domestic financial centers in China.

This study aims to find a relationship between the distribution of locals inside of Sweden and the municipalities’ relative concentration of foreigners. With the usage of data found in the website Statistics Sweden, we aim to investigate the existence of any relationship between the local population size of a municipality against the number of foreigners present in said municipalities, and see whether foreigners and immigrants are more concentrated in more populated municipalities rather than less populated ones. We aim to do this by utilizing multiple regression and dummy variables to identify whether there is a significant extra negative or positive effect on foreigners. The answer seems to be that foreigners are in fact more concentrated in more locally populated municipalities, rather than less populated ones

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The increasing concern for emissions and pollutants from power generation plants has increased the desire for and the study of biomass fuels. Biomass combustion produces less carbon monoxide as well as other greenhouse gases. Black liquor is a byproduct from the Kraft process in making paper. Black liquor can be gasified and used as a fuel in recovery boilers and fluidized bed steam reformers. Recovery boilers have a low efficiency and are used today because of their reliability. Steam reformers have a much higher efficiency but they are a relatively new science and are not as reliable. One of the reasons why steam reformers are not reliable is due to the agglomeration of the particles in the fluidized bed. The particles will stick together, agglomerate, at temperatures much lower than their melting temperature. The strength of these bonds and the temperature at which the bed agglomerates were studied as well as the effect of particle size on the heat transfer coefficient from the heaters to the bed material by means of experimentation and analysis. As the carbon content decreases, the agglomeration temperature also decreases. For 0.3% carbon content coated particles, the agglomeration temperature is approximately 490 ºC. The temperature at which the inter-particle bond strength increases dramatically also decreases. By comparing the inter-particle force with the collision force between particles, it was observed that when the velocity of the particles decreases below 1/500th of the free stream velocity, the particles will agglomerate.

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