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Estudo do processo de aglomeração de pectina em leito fluidizado : efeito sobre as propriedades físico-químicas; Study of the pectin agglomeration process : effect on physicochemical properties

Talita Akemi Medeiros Hirata
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 24/03/2011 PT
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36.49%
Com o aumento da variedade de produtos em pó, produzidos por diversas indústrias alimentícias, há a necessidade de informações detalhadas a respeito do seu manuseio e processamento voltadas para a aplicação em diversos produtos alimentares. O aumento do tamanho de partículas finas pelo processo de aglomeração em leito fluidizado proporciona benefícios que incluem redução de perdas de finos e perigo ou desconforto na manipulação, e principalmente, melhoria das propriedades de instantaneização do pó, por exemplo, solubilidade, dispersão em líquidos etc. Os leitos fluidizados pulsados possuem uma série de vantagens em relação aos leitos convencionais, podendo-se destacar a fácil fluidização de partículas irregulares com tamanhos distintos. A pectina é muito conhecida como agente geleificante e vem sendo utilizada na forma de pó. Este trabalho teve como objetivo estudar as modificações nas propriedades físicas da pectina em pó produzida por aglomeração em leito fluidizado pulsado. As condições ótimas de processo foram obtidas por meio de planejamento experimental, ou delineamento composto central 24. As variáveis estudadas foram temperatura do ar, vazão de ligante, velocidade de fluidização do ar e frequência de pulsação do ar. Obteve-se um rendimento no processo superior a 80% e o aumento de tamanho da partícula foi de quase 340%. O produto foi caracterizado por análises de umidade...

Connecting Lagging and Leading Regions : The Role of Labor Mobility

Lall, Somik V.; Timmins, Christopher; Yu, Shouyue
Fonte: Banco Mundial Publicador: Banco Mundial
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46.35%
How can policies improve the welfare of people in economically lagging regions of countries? Should policies help jobs follow people? Or should they enable people to follow jobs? In most countries, market forces have encouraged the geographic concentration of people and economic activities - policies that try to offset these forces to encourage balanced economic growth have largely been unsuccessful. However, policies that help people get closer to economic density have improved individual welfare. In this paper, the authors examine the migration decisions of working-age Brazilians and find that the pull of higher wages in leading regions has a strong influence on the decision to migrate. However, many people are also "pushed" to migrate, starved of access to basic public services such as clean water and sanitation in their hometowns. Although migration is welfare-improving for these individuals, the economy may end up worse off as these migrants are more likely to add to congestion costs in cities than to contribute to agglomeration benefits. Encouraging human capital formation can stimulate labor mobility for economic gain; and improving access to and quality of basic services in lagging regions will directly improve welfare as well as reduce the type of migration motivated by the search for life-supporting basic services.

Urban Transport : Can Public-Private Partnerships Work?

Engel, Eduardo; Galetovic, Alexander
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
EN_US
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46.54%
Cities exist, grow, and prosper because they take advantage of scale economies and specialization wrought by agglomeration. But output growth inevitably stresses transport infrastructure because production requires space and mobility. To prevent congestion from crowding out agglomeration benefits and to expand the supply of urban land, cities must invest in transport infrastructure. Building more infrastructures, especially highways, just fosters sprawl and fails to reduce congestion that people respond to more capacity by driving more and wasting even more time. In this view, a central task for policy makers and planners is to curb the preference for cars. Proponents of this view advocate subsidizing public transportation; enacting taxes and restrictions to raise the costs of owning and driving cars; and establishing zoning regulations to foster compact living, shrink the spatial distribution of activities, and reduce the number of vehicle trips. Yet urban planners often lack formal and real authority to cut through the bureaucratic web of multiple authorities and jurisdictions. Can public-private partnerships (PPPs) deal with these problems better than conventional public provision and ensure proper maintenance...

Growing through Cities in Developing Countries

Duranton, Gilles
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
EN_US
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36.49%
This paper examines the effects of urbanization on development and growth. It begins with a labor market perspective and emphasizes the importance of agglomeration economies, both static and dynamic. It then argues that more productive jobs in cities do not exist in a void and underscores the importance of job and firm dynamics. In turn, these dynamics are shaped by the broader characteristics of urban systems. A number of conclusions are drawn. First, agglomeration effects are quantitatively important and pervasive. Second, the productive advantage of large cities is constantly eroded and must be sustained by new job creation and innovation. Third, this process of creative destruction in cities, which is fundamental for aggregate growth, is determined in part by the characteristics of urban systems and broader institutional features. The paper highlights important differences between developing countries and more advanced economies. A major challenge for developing countries is to reinforce the role of their urban systems as drivers of economic growth.

Agglomeration Economies and Productivity in Indian Industry

Lall, Somik; Shalizi, Zmarak; Deichmann, Uwe
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
EN_US
Relevância na Pesquisa
36.59%
"New" economic geography theory, and the development of innovative methods of analysis have renewed interest in the location, and spatial concentration of economic activities. The authors examine the extent to which agglomeration economies contribute to economic productivity. They distinguish three sources of agglomeration economies: 1) At the firm level, from improved access to market centers. 2) At the industry level, from enhanced intra-industry linkages. 3) At the regional level, from inter-industry urbanization economies. The input demand framework they use in analysis, permits the production function to be estimated jointly with a set of cost shares, and, makes allowances for non-constant returns to scale, and for agglomeration economies to be factor-augmenting. They use firm-level data for standardized manufacturing in India, together with spatially detailed physio-geographic information that considers the availability, and quality of transport networks linking urban centers - thereby accounting for heterogeneity in the density of transport networks...

Urban Transport : Can Public-Private Partnerships Work?

Engel, Eduardo; Galetovic, Alexander
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
EN_US
Relevância na Pesquisa
46.54%
Cities exist, grow, and prosper because they take advantage of scale economies and specialization wrought by agglomeration. But output growth inevitably stresses transport infrastructure because production requires space and mobility. To prevent congestion from crowding out agglomeration benefits and to expand the supply of urban land, cities must invest in transport infrastructure. Yet balancing the growing demand for infrastructure with its supply is often difficult. In particular, many cities lack the funding to maintain and expand streets and urban highways. Also problematic is that roads are managed like a social service rather than subjected to market discipline. This leads to the central question of this chapter: Can public-private partnerships (PPPs) deal with these problems better than conventional public provision and ensure proper maintenance, timely expansion, and less congestion? And if so, how? To answer these questions, the paper examines what PPPs can do and what they need to work, focusing in particular on the role of institutions. This is followed by an investigation of common PPP pitfalls and the ways in which they can be avoided. The paper concludes with a case study of a successful transportation PPP in Chile that emphasizes the importance of planning.

Regional Economic Impact Analysis of High Speed Rail in China : Main Report

World Bank
Fonte: Washington, DC Publicador: Washington, DC
EN_US
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26.42%
This report reflects a two-stage work flow designed to fulfill the research objectives: stage one defined the methodology, and stages two tested this methodology and transferred the know-how to the China Railway Corporation and its consultants through case studies. Chapter two summarizes the theoretical framework within which regional economic impacts are discussed and quantified. Chapter three reviews current regional economic impact analyses in China. Chapter four summarizes the approach to practical regional impact assessment in other countries and reviews the relevance of the main methods in the Chinese context. Chapter five summarizes the work that has been carried out by the World Bank to date in estimating regional impacts in China. Chapter six develops a practical approach to quantifying the regional economic impacts of future HSR in China, including methods for data collection, surveys and interviews. Chapter seven presents the implementation of the methodology in the case studies and the interpretation of quantified model results. Chapter eight summarizes the conclusions and the recommendations for further work. In addition...

Infrastructure in Conflict-Prone and Fragile Environments

Ali, Rubaba; Barra, A. Federico; Berg, Claudia N.; Damania, Richard; Nash, John D.; Russ, Jason; Russ, Jason
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Trabalho em Andamento
EN_US
Relevância na Pesquisa
36.12%
In conflict-prone situations, access to markets is necessary to restore economic growth and generate the preconditions for peace and reconstruction. Hence, the rehabilitation of damaged transport infrastructure has emerged as an overarching investment priority among donors and governments. This paper brings together two distinct strands of literature on the effects of conflict on welfare and on the economic impact of transport infrastructure. The theoretical model explores how transport infrastructure affects conflict incidence and welfare when selection into rebel groups is endogenous. The implications of the model are tested with data from the Democratic Republic of Congo. The analysis addresses the problems of the endogeneity of transport costs and conflict using a novel set of instrumental variables. For transport costs, a new instrument is developed, the natural-historical path, which measures the most efficient travel route to a market, taking into account topography, land cover, and historical caravan routes. Recognizing the imprecision in measuring the geographic impacts of conflict...

Firms’ Locational Choice and Infrastructure Development in Rwanda

Iimi, Atsushi; Humphrey, Richard Martin; Melibaeva, Sevara
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Trabalho em Andamento
EN_US
Relevância na Pesquisa
36.41%
Agglomeration economies are among the most important factors to increase firm productivity. However, there is little evidence supportive of this in Africa. By applying the conditional and nested logit models, this paper examines the relationship between firm locations and infrastructure accessibility in Rwanda. It is found that agglomeration economies matter to even one of the smallest countries in Africa. It is also found that infrastructure availability has an important role in affecting the firm location decision. Electricity access and transport connectivity to the domestic and international markets are found to be important to attract new investment. In addition, the quality of local labor supplied, measured by educational attainment, is found as an important determinant of firm location, while the effect of labor costs remains inconclusive.

Mecanismos de aglomeração de polissacarídeos em pó em leito fluidizado pulsado; Mechanisms of polysaccharides powder agglomeration in pulsed fluidized bed

Talita Akemi Medeiros Hirata
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 19/08/2015 PT
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36.52%
Com o aumento da variedade de produtos em pó produzidos por diversas indústrias alimentícias, há a necessidade de informações detalhadas a respeito do seu manuseio e processamento voltadas para a aplicação em diversos produtos alimentares. O aumento do tamanho de partículas finas pelo processo de aglomeração proporciona benefícios que incluem redução de perdas de finos e desconforto na manipulação, e principalmente, melhora as propriedades de instantaneização do pó. O uso de leitos fluidizados pulsados possui uma série de vantagens em relação aos leitos convencionais, podendo-se destacar a fácil fluidização de partículas irregulares com tamanhos distintos. A influência de diferentes parâmetros de processo tem sido investigada. No entanto, substâncias como esferas de vidro, carbonato de cálcio e areia são frequentemente utilizadas, representando muito pobremente o comportamento dos alimentos frente à aglomeração. Além disso, os mecanismos de aglomeração de partículas amorfas e viscoplásticas com agentes ligantes estão longe de serem elucidados. O objetivo do presente trabalho foi estudar a influência das propriedades físico-químicas e de transporte nos mecanismos de aglomeração em leito fluidizado pulsado da pectina de alta metoxilação...

Jobs and Land Use within Cities; A Survey of Theory, Evidence, and Policy

Goswami, Arti Grover; Lall, Somik V.
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Working Paper; Publications & Research :: Policy Research Working Paper; Publications & Research
ENGLISH; EN_US
Relevância na Pesquisa
36.41%
Over the last century, the urban spatial structure of cities has transformed dramatically from the traditional monocentric configuration to varying forms of decentralized organization. This paper reviews the theory and empirical evidence to understand the urban morphology of jobs and land use within a city. This survey highlights four broad insights: (i) The evolution of monocentric to polycentric centers has been accompanied by structural changes in the city. (ii) The internal geography of a city is an outcome of the trade-off between the pull from agglomeration economies and the push from congestion. (iii) The presence of externalities implies that the equilibrium spatial organization achieved by profit-maximizing firms may not necessarily be optimal. This justifies the role of public policy in addressing the associated market failures. (iv) The productive edge and competitiveness of a city can be enhanced by introducing policies that increase the overall connectivity to take advantage of economic opportunities across the metropolitan area. The survey also puts together a wide range of policy instruments that are useful in closing the gap between equilibrium urban spatial structure and the optimal outcome.

Urbanization beyond Municipal Boundaries : Nurturing Metropolitan Economies and Connecting Peri-Urban Areas in India

World Bank
Fonte: Washington, DC: World Bank Publicador: Washington, DC: World Bank
Tipo: Publications & Research :: Publication; Publications & Research :: Publication
ENGLISH; EN_US
Relevância na Pesquisa
36.61%
The report is organized into three chapters: chapter two looks at the pace and patterns of India's urbanization, providing a 100-year perspective on demographic shifts and a 20-year perspective on the spatial distribution of jobs across India's portfolio of settlements. The review is based on a careful, spatially detailed analysis of data from economic and demographic censuses, annual surveys of industry, national sample surveys, and special surveys of freight transport. This chapter provides diagnostics on whether Indian industry is adequately exploiting agglomeration economies and whether there are hints of specific barriers to the natural tendency of standardized industry to reshuffle from large metropolitan areas to smaller urban areas. Chapter three examines specific policy issues and investment bottlenecks that are curbing the pace and benefits of urbanization in India. The policy issues relate to land markets and housing, connectivity (within and between cities), and access to basic services. The purpose of this analysis is to unravel the specific distortions that may be preventing India from reaping the entire range of benefits of urbanization. Chapter four provides some options for policy reform...

Urbanization and Agglomeration Benefits : Gender Differentiated Impacts on Enterprise Creation in India's Informal Sector

Ghani, Ejaz; Kanbur, Ravi; O'Connell, Stephen D.
Fonte: World Bank, Washington, D.C. Publicador: World Bank, Washington, D.C.
Tipo: Publications & Research :: Policy Research Working Paper; Publications & Research
ENGLISH; EN_US
Relevância na Pesquisa
46.54%
This paper presents an exploration at the intersection of four important themes in the current development discourse: urbanization, agglomeration benefits, gender and informality. Focusing on the important policy objective of new enterprise creation in the informal sector, it asks and answers four specific questions on the impact of urbanization and gender. It finds that (i) the effect of market access to inputs, on creation of new enterprises in the informal sector, is greater in more urbanized areas; (ii) This "urbanization gradient" also exists separately for the creation of female owned enterprises and male owned enterprises; (iii) there is a differential impact of female specific market access compared to male specific market access, on female owned enterprise creation in the informal sector ; and (iv) gender specific market access to inputs matters equally in more or less urbanized areas. Among the policy implications of these findings are that (i) new enterprise creation by females can be encouraged by urbanization...

Urbanization and (In)Formalization

Ghani, Ejaz; Kanbur, Ravi
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Policy Research Working Paper; Publications & Research
ENGLISH; EN_US
Relevância na Pesquisa
36.47%
Two of the great stylized predictions of development theory, and two of the great expectations of policy makers as indicators of progress in development, are inexorable urbanization and inexorable formalization. Urbanization is indeed happening, beyond the "tipping point" where half the world's population is now urban. However, formalization has slowed down significantly in the past quarter century. Indeed, informality has been increasing. This disconnect raises a number of questions for development analysis and development policy. Is the link between urbanization and formalization more complex than what had been thought? What does this mean for policy? The first core section of this paper asks what exactly is meant by formality and informality. The second core section turns to processes of urbanization and asks how these processes intersect with and interact with the incentives to formalize. The paper examines why cities attract the informal sector and the role that urbanization plays in growth and job creation through both the formal and informal sectors. Cities generate agglomeration benefits in the informal sector...

Promoting Women's Economic Participation in India

Ghani, Ejaz; Kerr, William; O'Connell, Stephen D.
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Brief; Publications & Research
ENGLISH; EN_US
Relevância na Pesquisa
36.47%
Despite rapid economic growth, gender disparities in women's economic participation have remained deep and persistent in India. What explains these gender disparities? Is it poor infrastructure, limited education, or the composition of the labor force and industries? Or is it deficiencies in social and business networks and a low share of incumbent female entrepreneurs? This note analyzes the spatial determinants of female entrepreneurship in India in the manufacturing and services sectors. It finds that good infrastructure and education predict higher female entry shares. Gender networks also influence women's economic participation, as strong agglomeration economies exist in both manufacturing and services. A higher female ownership among incumbent businesses within a district-industry predicts a greater share of subsequent female entrepreneurs. Moreover, higher female ownership of local businesses in related industries (similar labor needs, input-output markets) predicts greater relative female entry rates. Unlocking female empowerment and entrepreneurship is a direct path to shared prosperity and a more dynamic and sustainable growth.

Urbanization and the Geography of Development

Henderson, J. Vernon
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Working Paper; Publications & Research
ENGLISH; EN_US
Relevância na Pesquisa
36.33%
This paper focuses on several interrelated key questions on the geography of development. Although we herald cities with their industrial bases as 'engines of growth,' does industrialization in fact drive urbanization?1 What economic activities do cities of different sizes undertake? Does this change as countries develop? If so, what are the policy implications? Do development policies have a big-city bias? If so, what does this imply for growth and inequality, and what are appropriate place-based policies? Should countries have policies concerning optimal city sizes or city-size distributions? Urbanization is central to the development process. Employment shifts out of agriculture into industry, and industrial production proceeds most effectively in cities, with their agglomeration economies. Cities are thus viewed as engines of growth. While such relationships appear in the data, the process is not straightforward. Among developing countries, changes in income or industrialization correlate only weakly with changes in urbanization. This suggests that policy and institutional factors may also influence the urbanization process...

Spatial costs in a monocentric city (and implications for agglomeration)

Wenban-Smith, Hugh B.
Fonte: Spatial Economics Research Centre (SERC), London School of Economics and Political Science Publicador: Spatial Economics Research Centre (SERC), London School of Economics and Political Science
Tipo: Monograph; NonPeerReviewed Formato: application/pdf
Publicado em /10/2009 EN; EN
Relevância na Pesquisa
36.21%
Using water supply as a model for a wider range of infrastructure services, the effect of a negative exponential density gradient on distribution costs is investigated for four monocentric urban development scenarios: (a) Densification; (b) Dispersion; (c) Suburbanisation; and (d) Constant density. It is shown that economies of scale in production can be outweighed by diseconomies in distribution in cases (b) and (c), suggesting that the agglomeration benefits of infrastructure cannot be taken for granted. They depend as much on the effect of density on distribution costs as the effect of size on production costs.

What makes cities more productive? Agglomeration economies and the role of urban governance: evidence from 5 OECD countries

Ahrend, Rudiger; Farchy, Emily; Kaplanis, Ioannis; Lembcke, Alexander C.
Fonte: Spatial Economics Research Centre Publicador: Spatial Economics Research Centre
Tipo: Monograph; NonPeerReviewed Formato: application/pdf
Publicado em /07/2015 EN; EN
Relevância na Pesquisa
36.47%
This paper estimates agglomeration benefits across five OECD countries, and represents the first empirical analysis that combines evidence on agglomeration benefits and the productivity impact of metropolitan governance structures, while taking into account the potential sorting of individuals across cities. The comparability of results in a multi-country setting is supported through the use of a new internationally-harmonised definition of cities based on economic linkages rather than administrative boundaries. In line with the literature, the analysis confirms that city productivity increases with city size but finds that cities with fragmented governance structures tend to have lower levels of productivity. This effect is mitigated by the existence of a metropolitan governance body.

Rocketing rents the magnitude and attenuation of agglomeration economies in the commercial property market

Koster, Hans R. A.
Fonte: Spatial Economics Research Centre (SERC), London School of Economics and Political Science Publicador: Spatial Economics Research Centre (SERC), London School of Economics and Political Science
Tipo: Monograph; NonPeerReviewed Formato: application/pdf
Publicado em /01/2013 EN; EN
Relevância na Pesquisa
26.49%
Rocketing rents in urban areas are likely explained by agglomeration economies. This paper measures the impact of these external economies on commercial property values using unique micro�]data on commercial rents and employment. A measure of agglomeration is employed that is continuous over space, avoiding the modifiable areal unit problem. To distinguish agglomeration economies from unobserved endowments and shocks, I use temporal variation in densities and instrumental variables. The spatial extent of agglomeration economies is determined by estimating a spatial bandwidth within the model. The results show that agglomeration economies have a considerable impact on rents: a standard deviation increase in employment density leads to an increase in rents of about 10 percent. The geographical extent of these benefits is about 15 kilometres. The bias of ignoring time�]invariant unobserved endowments and unobserved shocks seems to be limited.

External benefits of brownfield redevelopment: an applied urban general equilbirum analysis

Vermeer, Niels; Vermeulen, Wouter
Fonte: Spatial Economics Research Centre, London School of Economics and Political Science Publicador: Spatial Economics Research Centre, London School of Economics and Political Science
Tipo: Monograph; NonPeerReviewed Formato: application/pdf
Publicado em /01/2012 EN; EN
Relevância na Pesquisa
26.58%
Does brownfield redevelopment warrant government support? We explore several external benefits in an urban general equilibrium framework. Preferences are modelled such that demand for housing units in the city is downward sloping, which yields a more general setup than the extreme open and closed city cases. We shed light on the relative importance of general equilibrium effects of nonmarginal redevelopment projects and we isolate the external benefits of the removal of a local nuisance, the exploitation of agglomeration economies and the preservation of open space at the urban fringe. A numerical application indicates that local nuisance and agglomeration effects may push social returns significantly beyond the value of redeveloped land that accrues to its owner. However, depending on the price elasticity of urban housing demand and the strength of agglomeration economies, the amount of preserved greenfield land may be small and it only generates additional benefits to the extent that direct land use policies fail to internalize its value as open space.