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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

A regional analysis of supply in the Canadian pulp and paper sector

Klein, Stephen Richard January 1985 (has links)
The purpose of this thesis was to analyse the supply of pulp and paper products in the three major producing provinces of Canada, namely British Columbia, Ontario and Quebec. A translog restricted profit function and its first partial derivatives were estimated using the iterative seemingly unrelated regressions procedure. Derived demand equations for energy, fibre, labour and supply equations for net market pulp, newsprint and 'other paper and paperboard", (net market pulp and 'all paper and paperboard' for British Columbia) were obtained with net supplies as a function of each input and output price. The success of the model in representing the industry was mixed. Derived demand own price elasticities were, in almost all cases, negative as expected a priori. Negative own price elasticities were also found in many end product supply functions suggesting a misspecification of the supply relationship. The unexpected supply function results bring up questions about the degree of competitiveness in pulp and paper markets, and thus the validity of using the perfectly competitive market assumption in empirical studies. Finally the model was evaluated in the context of using the results in a spatial equilibrium model of the North American pulp and paper sector. / Forestry, Faculty of / Graduate
52

A comparative analysis of stability and structure-functional relationships of different xylanases

Tabosa-Vaz, Sacha 30 July 2013 (has links)
Submitted in complete fulfilment for Masters Degree in Technology: Biotechnology, Durban University of Technology, 2013. / A comparative thermostability analysis of different partially purified xylanases from Rhodothermus marinus, Bacillus halodurans, Thermomyces lanuginosus and Pulpzyme HC was studied using differential scanning fluorometry (DSF), fluorescence spectroscopy and circular dichroism (CD). The R. marinus xylanase was found to have an optimum temperature and pH of 90oC and 6 respectively while the B. halodurans xylanase was optimally active at 70oC and a broad range of alkaline pH of 8 - 10. The commercially available xylanase from T. lanuginosus showed optimal activity at 50oC and pH 7 while the Novozyme xylanase Pulpzyme HC showed optimal activity at 60oC and pH 7. Fluorescence spectroscopy monitored the microenvironment and fluorescence emission of Trp residues. In their native folded state, Trp are generally located in the core of the protein but during unfolding they become exposed. The fluorescence changes as the enzyme undergoes denaturation due to conformational changes and exposure of Trp residues. Differential scanning fluorometry (DSF) monitors thermal unfolding of proteins in the presence of a fluorescent dye such as Spyro Orange. A wide range of buffers were tested for their ability to increase the xylanase stability. T. lanuginosus had the greatest increase in melting temperature with 0.73M Bis Tris pH 6.5 and peaked highest at 78°C. The B. halodurans xylanase exhibited high pH stability (pH 4-10) and exhibited very little change in melting temperature, from 74°C-77°C over the twenty four different conditions. The R. marinus xylanase had no increase in melting temperature showing a maximum melting temperature of 90oC. Circular dichroism (CD) measures unequal absorption of right- and left-handed circularly polarized light by the molecule. The xylanase from R. marinus exhibited the lowest ΔG of 34.71kJ at 90°C as was expected. The B. halodurans xylanase showed a much higher ΔG of -52.71 at its optimum temperature of 70°C when compared with the xylanases from R. marinus and T. lanuginosus. When comparing the three xylanases activities at 70°C, it can be seen that the B. halodurans xylanase exhibited a lower relative activity then both R. marinus and T. lanuginosus xylanases. All three techniques offered different information on the structure and function relationship. Fluorescence spectroscopy, the change in conformation due to fluorescence emission as a result of increased temperature and salt concentrations. DSF, optimal conditions for increased stability and activity at higher temperatures and CD, conformational changes, the fraction of folded protein and change in Gibbs free energy over a range of temperature. / National Research Foundation
53

Local impacts of large investments

Lindgren, Urban January 1997 (has links)
The aim of the thesis is to investigate local impacts of large investments. This problem has been approached from three directions and, therefore, the study consists of three themes, namely: the changing spatial patterns of corporate activities, the short-term local economic impacts of invest­ments, and the long-term socio-economic impacts of investments on the local municipality. In order to put the impact studies of investments into a broader context the first theme provides an analysis of the macro-orientated processes that change the spatial pattern of a forest- based industry. The empirical investigation is based on a case-study of a major Swedish forest company (SCA — Svenska Cellulosa Aktiebolaget), analysing its development from the 1950s to the present (Paper I). The locational changes of production plants, sales units and headquarters have been mapped and, parallel to this study of the company's spatial evolution, the underlying corporate strategies are discussed. The second theme focuses on the short-term local economic impacts of investments which are carried out at production units. The empirical data has been collected from a major investment introducing a new technology (Light Weight Coated paper - LWC) at Ortviken, an SCA-owned paper mill in Sundsvall. The point of departure for the analysis is the identification of contracted suppliers and their location in order to obtain a picture of the investment's diffusion in the local economy. As the choice of supplier is an important part of the study, criteria on how suppliers are chosen have also been examined (Paper II). Moreover, by using results from a number of similar investment studies, an attempt is made to summarize general experiences within a tentative model for estimating the share of local purchase deriving from major investments: the Local or Non-Local (LNL) model (Paper III). The third theme of the thesis pinpoints long-term local impacts of large investments. The investment generates impacts not only concurrently with the implementation phase, but also during the operation period of the invested item. The investigation of long-term socio-economic impacts has been performed by two studies employing different methodological approaches. The first study (Paper IV) deals with ex ante local impacts of locating a nuclear waste repository in Storuman or Mala, two sparsely populated municipalities in northern Sweden. The model is a traditional macro- formulated cohort model which is combined with a 'basic/non-basic' assumption regarding the intcrdependency within the local trade and business. The second study (Paper V) refers once again to the forest-based industry by emphasising the long-term socio-economic impacts of the investment examined in Paper II. This paper employs a micro-analytical modelling approach, so that, the municipal population is represented individually within the model. A microsimulation model is elaborated in order to analyse the long-term (15 years) local population and labour market dynamics induced by the LWC-investment. Some major findings of the thesis are: * The share of local purchase is connected to the composition of the investment. Analyses have shown that the higher the technological demand and the more technically advanced the goods and services related to the investment, the smaller is the local share of the purchase. *  It has proved possible to trace chain effects on different local labour-markets induced by changes in production at a particular place of work. Through linkages between the partial labour markets the closure of a major place of work will not only affect the occupational groups to which laid-off employees belong, but also give rise to changes in unemployment levels in many other occupations. / digitalisering@umu
54

A study of the factors affecting the size distribution of micro-capsules for carbonless copy paper.

Chetty, Ezekiel. January 2002 (has links)
The process of micro-encapsulation by emulsifying a solution in a stirred tank has been accepted as the most suitable method for the production of microcapsules for carbonless copy paper and is currently used by Mondi Paper in Merebank. The focus of this project was to obtain a more uniform size distribution of the microcapsules so that oversize capsules would not smudge when they are coated on paper. There was also concern that the formation of very small ink/oil droplets was consuming wall material unnecessarily and was not contributing to the formation of an image on paper. The reduction of these tiny droplets would result in a saving of the cost of the wall material. Mondi currently produces microcapsules with an average diameter between 4 and 5 microns. The amount of capsules produced above 10 microns, the oversize, is less than 1 per cent (v/v) and the amount of capsules produced below 2 microns, the undersize, is between 25 and 30 per cent. Mondi wishes to reduce the amount of undersize capsules, thereby producing a narrower size distribution. This could result in large savings, as discussed above. It could also lead to the production of a six-sheet set of carbonless papers instead of the four-sheet set, which is currently produced. The production of microcapsules by emulsification was investigated in a 2.5-1iter laboratory tank, using an impeller measuring 45 mm in diameter. A range of agitation speeds was investigated and it was seen that at the lowest speed that formed emulsions, 6600 rpm, 15.03 per cent of undersize capsules was produced and an average capsule diameter of 7.57 microns, after 40 minutes of agitation. At the highest impeller speed, 8000 rpm, the average capsule diameter was reduced to 1.93 microns and 67.02 per cent of undersize capsules were classified as "undersize". No oversize capsules were observed. These capsule specifications were not favourable. Further experimentation showed that at 7500 rpm, an average capsule diameter of 5.12 microns and an undersize of 24.20 per cent were observed. The proportion of oversize capsules was 1.63 per cent. Since these results were similar to the results obtained from the plant, 7500 rpm was used accepted as the "standard" speed for the experiments. A reduction in the impeIler speed from 7500 rpm to 7200 rpm after the first 20 minutes of emulsification was one· way on reducing the proportion of undersize particles further. The proportion of undersize particles was reduced from 20.20 per cent to 19.71 per cent at standard conditions. The average capsule diameter and the oversize were not affected significantly. The effect of the emulsification temperature on the particle size distribution was investigated with temperatures ranging from 22 to 40°C, in increments of 2 QC. A temperature of 30 °c was used as a standard temperature as this temperature was being used at the plant. A decrease in the proportion of undersize capsules to 17.12 per cent was seen at temperatures below 30°C and an average of 23.87 per cent was noticed above 30 QC. Although the proportion of undersize capsules decreased, the average capsule diameter increased beyond the specified range to an average of 7.77 microns at temperatures below 30°C. At temperatures above 30 °c the average size was reduced to 5.59 microns. Hence the selection 000 °c as the optimum temperature was confirmed. Experimentation with the emulsification time showed that there were times when a unimodal size distribution was produced. However, these were at times just after the polymerisation had begun, and the reaction was not complete at this stage. A bimodal distribution was always noticed after 40 minutes of emulsification, i.e. after the completion of the reaction. The effects of the baffle widths on the microcapsules were also investigated. Baffle sizes of 5, 10 and 15 mm were used. It was shown that with an increase in baffle width, there was a decrease in the amount of undersize capsules produced. However, the average capsule diameter became too large. A baffle width of 5 mm was shown to produce desirable capsule sizes, although the undersize did not improve, or worsen. Too much of air was trapped in the emulsion when no baffles were used in the tank. Alternatives to the current surfactant, called "Lupasol" were tested so that Mondi could produce the capsules independently instead of relying on the original raw material supplier. This investigation was done based on limited informa.tion on Lupasol. Results from these experiments were inconclusive since more data on Lupasol was required. Samples of the microcapsule emulsion were sent to different companies, in South Africa and abroad, to determine whether the particle size analyser used at Mondi was giving correct results. The results obtained from the companies in South Africa differed by a small amount from that measured at Mondi. However, results obtained from companies abroad varied considerably and it is recommended that Mondi change their particle analyser settings. The power absorbed by the emulsion, in the laboratory-scale equipment was also found. This was determined by monitoring torque. The power was found to be 141.97 Wand the power number was calculated as 0.357. It was noted that the power per unit volume in the laboratory equipment was significantly higher than the plant data (47 kW/m3 vs. 12 kW/m3). The design of the impeller was not changed but the effect of baffle spacing was investigated. / Thesis (M.Sc.Eng.)-University of Natal, Durban, 2002.
55

Aligning corporate culture and product innovation at Sappi Fine Paper South Africa

24 March 2009 (has links)
M.B.A. / The paper industry and, more specifically, Sappi Fine Paper, has not been achieving the levels of innovation required to meet rapidly-changing market needs, especially when compared to manufacturers like 3M. The industry is therefore losing value and not achieving optimal returns on investment. The reasons for this lack of innovation are not known. This study aims to investigate these sub-optimal levels of innovation, and to define some of the possible reasons for it. The study begins with an examination of corporate culture and its impact on innovation. In this regard, a cultural audit was done on a selected group of Sappi employees involved in product development from manufacturing, and sales and marketing. The questionnaire used was aimed at measuring and quantifying innovation and creativity influencers, and both perceived and preferred dimensions of culture were recorded. A gap analysis was then undertaken between the two, and perceptual charts plotted for each of the research groups. The audit revealed that Sappi Fine Paper does, indeed, have a creative culture, but the gap analysis revealed that in certain dimensions there are large gaps between the perceived and preferred profiles. The most critical gap affecting innovation was the one in the “risk profile” dimension. This revealed a tendency for the company to be risk averse, while the expressed preference of staff is that it be more open to risk taking. The literature review also highlights the importance that risk taking plays in innovation. The conclusion drawn is that, in order to achieve improved levels of innovation, Sappi Fine Paper needs to support existing creativity with a greater openness to risk taking resulting in higher levels of innovation.
56

Sintering of fume deposits in kraft recovery boilers

Techakijkajorn, Udom 04 October 1995 (has links)
Fume, sub-micron aerosal particles in the combustion gases, have been identified as a cause of extensive plugging and fouling in the heat transfer section of a kraft recovery boiler in kraft pulp mills. After the deposition on the heat transfer surface, fume deposits will undergo the sintering process which causes densification and hardening, making them hard to remove. There has been relatively little information available on the kinetics of the sintering of fume particles, and no information on the modeling of the sintering process of this particular material. No conclusion about the effect of chloride species on the sintering of fume particles has been made. A series of sintering tests in air at various temperatures were conducted using dense pellets made from a specific fume dust which contains a low amount of chlorides. Each pellet was heated at a constant temperature, ranging from 300��C to 550��C, for a different time interval. By the study of the microstructural change of each sintered specimen, the initial stage, intermediate stage, and final stage of sintering were identified. By the presence of an empirical constant K���, the relative linear shrinkage data in the initial stage sintering fit well with the model proposed by Kingery and Berg��� when volume diffusion is the controlling mechanism. By the presence of an empirical constant K2 and the application of grain growth data, the porosity-time data in the intermediate stage sintering fit well with the model proposed by Coble����� when volume diffusion is the controlling mechanism. The apparent activation energy obtained from the initial stage sintering is equal to 54.5 �� 27.7 kcal/mol which is in good agreement with the apparent activation energy obtained from the intermediate stage sintering which is equal to 56.0 �� 31.3 kcal/mol. A semi-empirical model for the sintering process of this particular well-packed fume dust was formulated. The model does not apply well to the loosely packed fume dust due to some unidentified factors The same experiment was carried out for the other fume dust which contains a high amount of chloride. By the use of the fractional density, the qualitative comparison of the sintering of the low chloride and high chloride dusts was made. At low temperatures, the sintering rate of the high chloride fume dust is lower than that of the low chloride fume dust. At high temperatures, both dusts have the same sintering rate and can sinter close to the theoretical density. It is postulated here that the retarded grain growth rate for the high chloride dust can improve the densification process in the intermediate stage sintering. / Graduation date: 1996
57

Decomposition of integer programs with application to cutting stock and machine allocation /

Menon, Syam Sankar. January 1997 (has links)
Thesis (Ph. D.)--University of Chicago Graduate School of Business, December 1997. / Includes bibliographical references.
58

Two-dimensional flow of fluids in deformable porous media.

Peterson, Richard M. 01 January 1969 (has links)
No description available.
59

The Development of a simulation-optimization program for the pulp and paper industry.

Saffran, Kenneth E. 01 1900 (has links)
No description available.
60

A Study on Applying Analytic Hierarchy Process to Technician Performance Evaluation for the Paper Industry

Tzeng, Jeng-tzeng 22 June 2005 (has links)
A Study on Applying Analytic Hierarchy Process to Technician Performance Evaluation for the Paper Industry Abstract The papermaking business is one of the primary industries closely associated with people¡¦s livelihood. Its growth that shows a positive relationship with both Gross National Product and the education index serves as a major indicator of the economic progress and cultural level of a nation. For decades, with domestic economic growth and increment of national income, prosperity has been brought to the Taiwan Paper Industry. However, under the great impact from the society in recent years, enterprises with inappropriate business management and inferior performance may be struggling for survival, or even have been eliminated. In face of such challenges, to work out an approach to exert the maximum effect of human resources by employing an effective system for performance management to further enhance the competence of the organization has become an urgent issue for enterprise managers and human resource management professionals. Due to the skill-intensive feature of the paper industry, the performance evaluations of technicians who play a decisive role in the organizations are obviously significant. Analytic Hierarchy Process is adopted in this study in an attempt to discuss the critical elements of the technician performance evaluation for the paper industry and construct a hierarchical appraisal system, expecting to provide managers of the paper industry with an appropriate evaluation method to facilitate performance management. The achievements attained in this study are as follows: 1. Discussions on the present conditions of the performance evaluation for the paper industry. 2. Construction of the hierarchical appraisal system for technician performance evaluation. 3. The relative weights of the performance evaluation indicators with Analytic Hierarchy Process are applied. 4. The substance and significance of the performance evaluation indicators and relative weights. (1) Work achievement is a key factor to determine the quality of a technician. (2) Loyalty to the organization has received much attention, which facilitates innovation and improvement for the minorities. (3) Active professionals will be favored and valued. 5. Empirical applications. Three suggestions are proposed for the enterprises: (1) Constitute items and contents of the performance evaluation. (2) Integrate the performance evaluation into Human Resource Management. (3) Combine with the Human Resource Information System (HRIS).

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