The disintegration of agglomerates of solid charge used in a nickel flash furnace has been investigated. The in-flight agglomerate size of solid charge with different characteristics has been measured using turbulent conditions similar to a full-scale flash furnace. Plant observations indicated that under certain conditions solid charge was able to pass through the furnace shaft unreacted. The motivation for this work was to improve the understanding and the modelling of a flash furnace. A review of the literature revealed that the disintegration of agglomerates of solid charge is very important to the performance of a flash furnace, however, there has been no detailed study of the factors governing the disintegration of in-flight agglomerates of solid charge.A laboratory-scale experimental rig was constructed to non-intrusively measure the in-flight agglomerate size distribution of solid charge and to visualise the powder injection process, while using turbulent conditions similar to a flash furnace. A high-speed video technique and a laser diffraction technique were used to measure the wide range of in-flight agglomerate sizes present during powder injection. A range of variables including the particle size, turbulence level, packing density, particle shape, solid concentration, and moisture content were investigated.

Thesis (M.Ing. (Chemical Engineering))--North-West University, Potchefstroom Campus, 2009.

Technological position is a dimension along which organizations can either differentiate from or mimic the behavior of other organizations in the technological landscape. This paper is aimed at providing empirical evidence of the specific ways in which an organization’s technological position choice is impacted by the tension that arises from technological co-location; the information available to the focal firm; and the focal firm’s usage of such information. In this dissertation I examine the factors influencing technological agglomerations in technological positions in the technological landscape. I further examine how the organization’s experience impacts its strategic positioning choice while facing the tradeoff between the expected derivatives of co-location - opportunities and competition. I argue and find that an organization strategically positions itself in the technological landscape based not only on the information it has gathered on its technological environment but also using its own experience and information. Further, my findings show that the organization’s technological positioning choice reflects the tension between opportunity and competition, which questions the notion of isomorphism.

This dissertation consists of two essays dealing with the trends in industrial agglomeration and changes in the influence of micro-determinants of agglomeration due to globalization in the U.S. manufacturing agglomeration and the second essay discusses the impact of globalization on the micro-determinants of agglomeration. The first essay explores recent agglomeration trends in the U.S. manufacturing industries between 1988 and 2003 using employment and employment-based agglomeration measures such as Ellison-Glaeser Index and Gini index, and using Herfindahl index as a measure of industrial concentration due to scale economies. Between 1988 and 2003, forty two states lost and eight states gained manufacturing employment with a net loss of more than 5.13 million jobs nationwide. Middle Atlantic, New England, and South Atlantic are the three divisions with highest drops in manufacturing employment with Middle Atlantic division’s loss of 45 percent jobs, New England division’s loss of 44 percent and South Atlantic division’s loss of 28 percent of jobs in the manufacturing industries. Three states that experienced the most decrease in manufacturing jobs in 2003 measured in percent of their 1988 employment are New Jersey (51 percent), New York (51 percent), and Connecticut (48 percent). Textile and apparel industries, metal related industries and leather and leather goods industries etc. are among the industries that experienced relatively higher attrition in manufacturing jobs in 2003. Three trends are apparent. First, employment has declined across regions, years and industries. Second, the industries that were among the most agglomerated industries in 1988 have generally displayed decrease in agglomeration indices (both in terms of EGI and Gini measures) in later years including 2003. This trend may imply that for these industries, attrition of manufacturing employment in later years mainly occurred from the counties with relatively higher share of employment in the concerned industries in 1988. Third, industries that are found to be least agglomerated in 1988 have often displayed increase in agglomeration in later years including 2003. This trend may imply that for these industries, attrition of manufacturing employment in 2003. This trend may imply that for these industries, attrition of manufacturing employment in 2003 mainly occurred from the counties with lower employment share of the concerned industries in 1988. Similar trends are observed for the Herfindahl indices. Changes in the Herfindahl indices may be due to changes in traditional scale economies caused by advancements in the ICTs. The second essay explores the differential impacts of technological advancements and trade liberalization on the three Marshallian determinants of industrial agglomeration for U.S. manufacturing industries. These three micro-determinants of agglomeration are goods pooling (input sharing), labor pooling (availability of labor), and idea pooling (knowledge spillover). The impact of decrease in employment on industrial agglomeration is ambiguous, and warrants empirical investigation. An index of agglomeration is regressed on proxies for three micro-determinants of agglomeration, after controlling for transportation costs, natural advantage and other state level economic variables, and after inclusion of interaction variables for technological advancement and trade liberalization. The regression results for both the OLS and FE specifications are consistent with the hypothesis that there was a structural change in the effect of the micro-determinants of industrial agglomeration in the U.S. manufacturing industries beginning in 1995. In the second essay, we decompose the impact of globalization on three micro-determinants of agglomeration into two separate segments: impact of technological advancements and impact of trade liberalization. The findings are partially consistent with the hypothesis that globalization has attenuated the effect of micro-determinants of agglomeration as the influence of two out of three micro-determinants of agglomeration diminished in the post-1995 years relative to their pre-1995 levels. For example, in the post 1995 period in our base line model, influence of labor pooling is diminished by about 4 percent and influence of idea pooling has attenuated by about 1 percent from their pre-1995 levels. Contrary to our hypothesis, we find that the influence of goods pooling has increased as a micro-determinant of agglomeration in the post-1995 years relative to its pre-1995 levels. The attenuation in influence for labor pooling and increase in influence of goods pooling in the post-1995 period are statistically significant when attenuation of influence of idea pooling is not statistically significant. Also, when we decompose the total effect of globalization, we find the impact of technology to be greater than that of international trade. The key findings are robust to alternative specifications of the econometric model, particularly to changes in the proxies used for LP.

Technological position is a dimension along which organizations can either differentiate from or mimic the behavior of other organizations in the technological landscape. This paper is aimed at providing empirical evidence of the specific ways in which an organization’s technological position choice is impacted by the tension that arises from technological co-location; the information available to the focal firm; and the focal firm’s usage of such information. In this dissertation I examine the factors influencing technological agglomerations in technological positions in the technological landscape. I further examine how the organization’s experience impacts its strategic positioning choice while facing the tradeoff between the expected derivatives of co-location - opportunities and competition. I argue and find that an organization strategically positions itself in the technological landscape based not only on the information it has gathered on its technological environment but also using its own experience and information. Further, my findings show that the organization’s technological positioning choice reflects the tension between opportunity and competition, which questions the notion of isomorphism.

In many countries, the agricultural subsidy is the existence, whether in order to protect the livelihood of farmers, or to ensure a stable supply of domestic agricultural products, the agricultural subsidy is the subject which may not neglect easily. This article uses new viewpoint which is brought by the economic geography, discusses the influence which the agricultural subsidy brings. We find that: (1) Agricultural subsidy would cause worker's nominal wage to change, causing further changes in production costs, thus affecting the equilibrium output of firms. (2) When subsidies some agricultural region, not necessarily improve the level of subsidy region. (3) If the degree of freedom of trade is low level , subsidies will make up the region's income level.

none

The purpose of this study is to investigate the determinants of interstate migration in the United States (US) from the perspective of institutions and agglomeration economies. Dependent variables used in this study relate to the net interstate migration of four distinct demographic groups; migrants as whole (MIGRATE), migrants aged between 22 and 39 years of age (MIGR2239), migrants aged between 22 and 39 years of age educated to the undergraduate level (BAMIGR), and migrants aged between 22 and 39 years of age educated to the postgraduate level (MAMIGR). Independent variables proxying for institutions are sourced from both the Mercatus Center and the Fraser Institute. The Mercatus Center¡¦s economic freedom index (the MEFI) and overall freedom index (MOFI) represent the relative economic and overall freedoms enjoyed by residents of the 50 states. The Fraser Institute¡¦s economic freedom index (FIEFI) also measures economic freedom. Agglomeration economy proxies relate to both creativity levels in state, measured by Richard Florida¡¦s creativity index (SCI06), and education levels, measured by the percentage of a state¡¦s population educated to the undergraduate level (EDUBPLUS). It is well established that crime and climate are factors that influence migration and these variables are controlled for in this study by using murder rates in the largest in-state city (MURDER) and the average annual number of heating degree days (HDD) in a state. This study uses multivariate linear regression to analyze the variables and the findings emphasize the importance of both institutions and agglomeration economies in explaining the migration decisions of US citizens. Institutions, proxied for by greater economic and overall freedoms, are shown to be more important than agglomeration economies for migrants across a broad range of demographic. Institutions are less important, however, for younger, better educated migrants who reveal preferences for good agglomeration economies and particularly creativity.

Attachment of particles to one another due to action of certain inter-particle forces is called as particle agglomeration. It has applications ranging from efficient capture of ultra-fine particles generated in coal-burning boilers to effective discharge of aerosol sprays. Aerosol sprays have their application in asthma relievers, coatings, cleaning agents, air fresheners, personal care products and insecticides. There are several factors that cause particle agglomeration and based on the application, agglomeration or de-agglomeration is desired. These various factors associated with agglomeration include van derWaals forces, capillary forces, electrostatic double-layer forces, effects of turbulence, gravity and brownian motion. It is therefore essential to understand the underlying agglomeration mechanisms involved. It is difficult to perform experiments to quantify certain effects of the inter-particle forces and hence we turn to numerical simulations as an alternative. Simulations can be performed using the various numerical simulation techniques such as molecular dynamics, discrete element method, dissipative particle dynamics or other probabilistic simulation techniques. The main objective of this thesis is to study the geometric characteristics of particle agglomerates using dissipative particle dynamics. In this thesis, agglomeration is simulated using the features of dissipative particle dynamics as the simulation technique. Forces of attraction from the literature are used to modify the form of the conservative force. Agglomeration is simulated and the characteristics of the result ing agglomerates are quantified. Simulations were performed on a sizeable number of particles and we observe agglomeration behavior. A study of the agglomerates resulting from the different types of attractive forces is performed to characterize them methodically. Also as a part of this thesis, a novel, dynamic particle simulation technique was developed by interfacing MATLAB and our computational C program.

Industrial cluster is a geographical phenomenon in the process of industrial development. It means in a certain field, related enterprises and organizations gather together in a certain region and form an organic system with intact upstream, middle stream, and downstream structures. With support of suburban industry system, such system has formed the engines of regional economic development. After open policy and economic reformation, Zhejiang Province has achieved a great accomplishment in both economic and social development. Zhejiang Province is also one of the fast growing and the most vigorous provinces in Mainland China. The key features, like ¡§Small merchandise, big market¡¨, ¡§Small enterprise, big cluster¡¨, ¡§Small region, big industry¡¨, etc., in this region have aroused public interests and concerns. In this thesis, we explore the issue of industrial cluster and its relationship to regional economic development and growth in Zhejiang Province. The analysis of the issue is based primarily upon the theoretical arguments and secondary empirical evidence. Research suggests that agglomeration economies at the cluster level influence the competition more profoundly, and the agglomeration economies further to affect the whole region.