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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.
141

Enabled by the past : understanding endogenous innovation in mature industries

Onufrey, Ksenia January 2017 (has links)
Mature industries have played and still play a crucial role in national and world economies. To survive and retain competitiveness, they need to innovate, as innovation is the driver of economics growth and industrial transformation. However, existing research does not provide sufficient explanation of how innovation in mature industries can be enabled based on resources and internal development logic of those industries, i.e. endogenously. Some previous studies focused on incremental innovation patterns, which led to an underestimation of innovation potential of mature industries. Other studies acknowledged a high innovation potential of mature industries, but failed to explain how, through what mechanisms, industry-endogenous logic can bring about major innovations. Therefore, the purpose of this thesis is to systematically address, explain and conceptualize endogenous industry- innovation and its driving mechanisms in mature industries. To achieve this purpose, three main issues are addressed. First, the thesis investigates and conceptualizes the notion of industry endogenous innovation mechanisms based on the path dependency theory. Second, the thesis addresses strategic choices and actions by established companies that are rooted in the industry endogenous mechanisms and result in highly innovative outcomes. Third, the thesis systematically analyses different aspects of radicalness of innovations resulting from industry endogenous mechanisms. The thesis represents a qualitative, embedded case study with two main industry cases, i.e. the global lighting industry and the Swedish pulp and paper industry. The lighting industry and its sub-cases in the form of specific lighting technologies have been studied via the analysis of patents of leading lighting manufacturers, archival and secondary data sources as well as interviews with different types of actors in the industry. The pulp and paper industry and its sub-cases in the form of innovation initiatives have been studied with the help of interviews with leading manufacturers and research institutes, as well the analysis of annual reports and secondary data sources. The outcomes of the study are presented in the form of the thesis cover paper and five appended papers. The results show that innovations of any magnitude can be endogenously developed in mature industries. At the industry level, endogenous innovation is driven by innovation mechanisms that can be conceptualized as reactive sequences and self-reinforcing mechanisms. At the level of individual companies, the exploitation strategy corresponds to the logic of endogenous innovation mechanisms by enabling highly innovative outcomes and building on a wide range of resources available in the industry. The endogenous character of innovation mechanisms imposes certain limitations on the radicalness of the outcomes in the form of trade-offs in terms of how many and what particular aspects can be radically new at once. With these results, the thesis contributes to a more balanced overall understanding of innovation potential of mature industries and allows shifting the focus of discussion from whether mature industries can develop radical innovation to when and under what conditions they can succeed in this process. The results of the thesis also suggest several recommendations for managers in established companies with regard to how they can they can take advantage of industry endogenous innovation mechanisms. / Mogna branscher har traditionellt sett spelat och spelar fortfarande en viktig roll för såväl nationella ekonomier som för världsekonomin. För att överleva och behålla sin konkurrenskraft behöver mogna branscher fortsätta vara innovativa, eftersom innovation driver ekonomisk tillväxt. Även för enskilda, etablerade företag i sådana branscher är innovation centralt – de företag som inte lyckas med innovation riskerar att förlora i konkurrensen och bli ersatta av andra. Det finns emellertid än så länge inte någon bra förklaring till hur innovation i mogna branscher kan möjliggöras endogent, d v s baserat på befintliga resurser och branschens interna utvecklingslogik. Tidigare studier har antingen tenderat att underskatta innovationspotentialen i mogna branscher eller misslyckats med att visa hur – d v s genom vilka mekanismer – branschens egen logik kan möjliggöra radikala innovationer. Syftet med denna avhandling är att förklara och konceptualisera endogena innovation och dess drivmekanismer i mogna branscher. För att uppnå detta syfte undersöker avhandlingen endogena innovationsprocesser på såväl bransch- som företagsnivå samt analyserar i vilken utsträckning olika aspekter av radikala innovationer möjliggörs av endogena mekanismer. Avhandlingen är baserad på kvalitativa fallstudier av två branscher. Den första branschen är den globala belysningsindustrin, där olika belysningstekniker har studerats via analyser av patent, sekundära datakällor samt intervjuer med olika typer av aktörer i branschen. Den andra branschen är svensk pappersmassaindustri, där ett antal olika innovationsinitiativ har studerats framförallt med hjälp av intervjuer med ledande företag och forskningsinstitut. Avhandlingen består av en kappa och fem bifogade artiklar. Resultaten visar att alla typer av innovationer, inklusive radikala innovationer, kan utvecklas endogent i mogna branscher. På industrinivån drivs denna utveckling av innovationsmekanismer i form av reaktiva sekvenser och självförstärkande mekanismer. På företagsnivån kan processen drivas av en innovationsstrategi som bygger på exploatering av befintliga resurser. Trots att alla aspekter av radikala innovationer kan utvecklas endogent, medför endogena mekanismer emellertid vissa begränsningar i form av kritiska avvägningar när det gäller hur många och vilka aspekter som kan hållas radikala samtidigt. Med dessa resultat bidrar avhandlingen till en mer balanserad, övergripande förståelse för innovationspotentialen i mogna branscher och medger ett skifte av fokus i vetenskapliga diskussioner från frågan om mogna branscher kan utveckla radikala innovationer till när och under vilka villkor de kan lyckas med denna process. I avhandlingen ges även rekommendationer för ledare i etablerade företag med avseende på hur de kan dra nytta av branschens endogena innovationsmekanismer.
142

Avaliação da qualidade da madeira das espécies Acacia crassicarpa, Acacia mangium, Eucalyptus nitens, Eucalyptus globulus e Populus tremuloides / Evaluation of the wood quality of species Acacia crassicarpa, Acacia mangium, Eucalyptus nitens, Eucalyptus globulus and Populus tremuloides

Antunes, Fernanda Schablatura 10 June 2009 (has links)
As madeiras utilizadas para produção de polpa celulósica podem ser divididas em dois grupos em função da fibra: folhosas (fibra curta) e coníferas (fibra longas), as espécies de folhosas são destinadas especialmente a papéis de escrita e impressão. As principais espécies de folhosas utilizadas para produção de polpa de fibra curta em outros países são o Eucalyptus globulus (Península Ibérica e Chile), Eucalyptus nitens (Chile), Populus tremuloides (Canadá), Acacia mangium, Acacia crassicarpa (Indonésia). Este projeto tem por objetivo: avaliar e comparar o desempenho de madeiras utilizadas mundialmente para produção de polpa celulósica de fibra curta considerando parâmetros de qualidade da madeira tais como composição química, densidade básica, características anatômicas da madeira; com objetivo de fornecer informações estratégicas para o setor nacional de celulose e papel, visando o conhecimento e posicionamento em competitividade destas madeiras no mercado mundial. Para a realização deste trabalho foram coletadas 5 árvores de cada espécie as quais foram utilizados cavacos cortados manualmente obtidos de discos; com relação à madeira foram determinadas densidade básica, composição química e dimensões de fibras. Os resultados foram analisados estatisticamente sendo comparadas as diferentes espécies referentes à qualidade da madeira. / Wood used for pulp production may be divided in two major groups regarding fiber function: hardwood (short fiber) and softwood (long fibers). Hardwood species are mainly designated to writing and printing papers. Hardwood principal species used for production of short fiber pulp in other countries are Eucalyptus globulus (Iberian Peninsula and Chile), Eucalyptus nitens (Chile), Populus tremuloides (Canada), Acacia mangium and Acacia crassicarpa (Indonesia). This study aimed to evaluate and compare the performance of the main woods used worldwide for short fiber pulp production regarding wood quality parameters such as chemical composition, basic density and wood anatomical properties, in order to provide strategic information for national pulp and paper industry, aiming the knowledge and competitiveness of these woods at worldwide market. To accomplish this study, 5 trees from each species were collected and wood chips were manually cut. In relation to the wood, basic density, chemical composition and fiber lengths were determined. The results were statistically analyzed and the different species were compared regarding wood quality.
143

Avaliação da qualidade da madeira das espécies Acacia crassicarpa, Acacia mangium, Eucalyptus nitens, Eucalyptus globulus e Populus tremuloides / Evaluation of the wood quality of species Acacia crassicarpa, Acacia mangium, Eucalyptus nitens, Eucalyptus globulus and Populus tremuloides

Fernanda Schablatura Antunes 10 June 2009 (has links)
As madeiras utilizadas para produção de polpa celulósica podem ser divididas em dois grupos em função da fibra: folhosas (fibra curta) e coníferas (fibra longas), as espécies de folhosas são destinadas especialmente a papéis de escrita e impressão. As principais espécies de folhosas utilizadas para produção de polpa de fibra curta em outros países são o Eucalyptus globulus (Península Ibérica e Chile), Eucalyptus nitens (Chile), Populus tremuloides (Canadá), Acacia mangium, Acacia crassicarpa (Indonésia). Este projeto tem por objetivo: avaliar e comparar o desempenho de madeiras utilizadas mundialmente para produção de polpa celulósica de fibra curta considerando parâmetros de qualidade da madeira tais como composição química, densidade básica, características anatômicas da madeira; com objetivo de fornecer informações estratégicas para o setor nacional de celulose e papel, visando o conhecimento e posicionamento em competitividade destas madeiras no mercado mundial. Para a realização deste trabalho foram coletadas 5 árvores de cada espécie as quais foram utilizados cavacos cortados manualmente obtidos de discos; com relação à madeira foram determinadas densidade básica, composição química e dimensões de fibras. Os resultados foram analisados estatisticamente sendo comparadas as diferentes espécies referentes à qualidade da madeira. / Wood used for pulp production may be divided in two major groups regarding fiber function: hardwood (short fiber) and softwood (long fibers). Hardwood species are mainly designated to writing and printing papers. Hardwood principal species used for production of short fiber pulp in other countries are Eucalyptus globulus (Iberian Peninsula and Chile), Eucalyptus nitens (Chile), Populus tremuloides (Canada), Acacia mangium and Acacia crassicarpa (Indonesia). This study aimed to evaluate and compare the performance of the main woods used worldwide for short fiber pulp production regarding wood quality parameters such as chemical composition, basic density and wood anatomical properties, in order to provide strategic information for national pulp and paper industry, aiming the knowledge and competitiveness of these woods at worldwide market. To accomplish this study, 5 trees from each species were collected and wood chips were manually cut. In relation to the wood, basic density, chemical composition and fiber lengths were determined. The results were statistically analyzed and the different species were compared regarding wood quality.
144

Compósito cimento-lodo de ETE de indústria de papel para aplicação na construção civil / Composite cement-sludge from pulp and paper industry mills effluent treatment for use in building materials

Paiva, Samantha Nazaré de 26 April 2007 (has links)
O grande volume de resíduos sólidos industriais gerado pelo setor de celulose e papel e o alto custo do seu manejo estimulam pesquisas em busca de soluções mais adequadas para o seu gerenciamento. Uma alternativa que se destaca neste contexto é o aproveitamento destes resíduos em materiais de construção. Este trabalho visa o aproveitamento do lodo de ETE de indústria de papel na produção de compósitos cimentícios para uso na construção civil. Foi estudada a influência de diferentes teores da adição do lodo de ETE (5%,10%,20% e 30% em massa) em argamassa de cimento e areia, com relação água-cimento de 0,65. Determinou-se para o resíduo: teor de umidade; massa unitária; massa específica; pH; sazonalidade de geração e teor de sólidos fixos e para o compósito: massa específica aparente; absorção de água por imersão; absorção de água por capilaridade; retratibilidade; isolamento acústico; resistência à compressão e análise da microestrutura. O resíduo foi classificado como Classe II – A, não inerte e não perigoso, o que indica alto potencial para aproveitamento em materiais de construção. Sua incorporação na argamassa aumentou a absorção de água por capilaridade em 12,76 % e por imersão em 18,93% no traço com 30% de resíduo para a empresa "A". Houve também a diminuição da resistência à compressão com a incorporação do resíduo, entretanto definiu-se o ponto-ótimo de incorporação em 12% para as duas empresas avaliadas, garantindo assim a resistência mínima à compressão de 2,5 MPa, exigência para blocos sem função estrutural. A incorporação de resíduo também apresentou decréscimo na massa específica do compósito de 14% na empresa "A" e de 34% para a empresa "B" para os traços de 30% de resíduo. Os resultados permitem concluir que este compósito é adequado para uso em materiais de construção sem função estrutural. / The large volume of industrial solids residues generated by the pulp and paper sectors and its high management cost stimulate research aiming at finding adequate solutions to its management. An alternative that shows high potential in this context is using these residues in building materials. This work aims at studying the use of paper's mills effluent treatment solid waste in the production of cement composites to be used in construction. The influence of adding different sludge proportions (5%,10%,20% and 30% in mass) in cement and sand mortar, with a water-cement relation of 0,65 was studied. The humidity ratio, unit mass, specific mass, pH, generation season and fixed solid concentration for the residue; and specific apparent mass, water absorption by immersion, water absorption by capillarity, acoustic isolation, compression resistance and microstructure analysis for the composite. The residue was classifies as Class II – A, not inert and not dangerous, which indicated high potential for use as building materials. Its use in the mortar increased the water absorption by capillarity in 12.76% and in immersion by 18.93% in the trace of 30% residue from company "A". There was also a decrease in compression strength when the residue was incorporated, however the optimal incorporation point was defined in 12% for both evaluated firms, guaranteeing the minimum compression resistance of 2.5 MPa, required for block without structural function. The residue incorporation also presented a decrease in the composite specific mass of 34% for company "B" and 1% for company "A" for the traces of 30% residue. The results allow us to conclude that this composite is adequate for use as building materials with no structural function.
145

ESTUDO ELETROQUÍMICO E DA CORROSÃO DO AÇO ASTM 285 GRAU C, NAS REGIÕES DE SOLDA E DA ZONA TERMICAMENTE AFETADA, EM SOLUÇÕES DE LICOR BRANCO, UTILIZADO EM DIGESTORES DA INDÚSTRIA DE PAPEL E CELULOSE, E SEUS PRINCIPAIS COMPONENTES / ESTUDO ELETROQUÍMICO E DA CORROSÃO DO AÇO ASTM 285 GRAU C, NAS REGIÕES DE SOLDA E DA ZONA TERMICAMENTE AFETADA, EM SOLUÇÕES DE LICOR BRANCO, UTILIZADO EM DIGESTORES DA INDÚSTRIA DE PAPEL E CELULOSE, E SEUS PRINCIPAIS COMPONENTES

D’avila, Ariel Leandro 25 August 2016 (has links)
Made available in DSpace on 2017-07-21T20:43:49Z (GMT). No. of bitstreams: 1 Dis_Ariel_final.pdf: 5083548 bytes, checksum: acac140ede5eeafdd769aa58a612e863 (MD5) Previous issue date: 2016-08-25 / This work aims to study the electrochemical steel ASTM A285 Grade C and the same welded with coated electrode AWS E 7018 in the solution of industrial white liquor used in pulp and paper industry by the Kraft method. Samples were withdrawn by electroerosion into three regions: the base metal (BM), the heat affected zone (HAZ) and at the weld metal (WM). Corrosion rates of the three metal regions were determined in 8°C, 16°C, 24°C, 35°C, 42°C, 50°C and 60°C temperature. The values of corrosion rates were compared with the BM, ZTA and WM corrosion rates in electrolytic solutions of the main chemical components of the industrial white liquor in the same temperature range. These solutions were 0,1 mol/L of Na2SO4; 2.276 mol/L of NaOH; 0.126 mol/L of Na2S; 0.128 mol/L of Na2CO3 and simulated white liquor composed of the above solutions with the same molar concentrations. The BM to 24°C, industrial white liquor aerated presented corrosion rate of 0.022 mm/year, 0.045 mm/year for the HAZ and 0.032 mm/year for the WM. It was observed that the HAZ corrosion rates were higher than BM and WM in all solutions studied. Lower corrosion rates were in Na2CO3, followed by NaOH, Na2S, simulated white liquor and finally with the highest corrosion rates in white liquor industry. All solutions are presented alkaline, except sodium sulfate, and it was observed that the three regions are passivated when compared to a reference solution of 0.1 mol/L Na2SO4, and aerated with a pH between 6.0 to 6.5. This passivation film are complex chemical composition due to the presence in solution of OH- HS- ion. From the corrosion potentials of BM in each solution and the pH values it was found that the BM region is passivated according iron Pourbaix diagram in water. Chronoamperometry and voltammetric studies showed that these passivation films that promote greater protection against corrosion, they are solubilized in NaOH solution, simulated white liquor and industrial white liquor when submitted to anodic polarization in potential near at +2.0 V versus saturated calomel electrode. In Na2S and Na2CO3 solution was observed the formation of thick deposits on the surface of BM and when analyzed by EDS was observed the presence of phases such as oxides, sulfides and possibly iron carbonate. / Este trabalho tem como objetivo o estudo eletroquímico do aço ASTM A285 Grau C soldados com eletrodo revestido AWS E 7018 em meio de licor branco industrial empregado na indústria de papel e celulose pelo método Kraft. As amostras foram retiradas por eletroerosão em três regiões: metal base (MB), região termicamente afetada pela soldagem (ZTA) e pelo metal de solda (MS). As taxas de corrosão das três regiões metálicas foram determinadas em temperaturas de 8°C a 60°C. Os valores das taxas de corrosão foram comparados com as taxas de corrosão do MB, ZTA e MS em soluções eletrolíticas dos principais componentes químicos do licor branco industrial, no mesmo intervalo de temperatura. Estas soluções foram de 0,1 mol/L de Na2SO4; 2,276 mol/L de NaOH; 0,126 mol/L de Na2S; 0,128 mol/L de Na2CO3 e em um licor branco simulado composto pelas soluções acima com as mesmas concentrações molares. O MB, a 24°C, em licor branco industrial, aerado, apresentou taxa de corrosão de 0,022 mm/ano, 0,045 mm/ano para a ZTA e 0,032 mm/ano par o MS. Observou-se que as taxas de corrosão da ZTA foram superior a do MB e MS em todas as soluções estudadas. As taxas de corrosão mais baixas foram em Na2CO3, seguido pela solução de NaOH, Na2S, licor branco simulado e finalmente, com as maiores taxas de corrosão, em licor branco industrial. Todas as soluções apresentaram-se alcalinas, exceto a de sulfato de sódio, e constatou-se que as três regiões encontravam-se passivadas quando comparada a uma solução de referência de 0,1 mol/L de Na2SO4,aerada e com pH entre 6,0 a 6,5. Estes filmes de passivação são de composição química complexa devido a presença em solução de íon OH- e HS-. A partir dos potenciais de corrosão do MB em cada solução e dos valores do pH foi verificado que a região do MB encontra-se passivado segundo o diagrama de Pourbaix de ferro em água. Estudos voltamétricos e de cronoamperometria mostraram que estes filmes de passivação, que promovem uma maior proteção contra a corrosão, são solubilizados em meio de NaOH, licor branco simulado e no licor branco industrial quando submetidos a polarizações anódicas em potenciais próximos de +2,0 V versus eletrodo de calomelano saturado. Em solução de Na2S e Na2CO3 foi observado à formação de depósitos espessos sobre a superfície do MB e quando analisados por EDS, observou-se a presença de fases como de óxidos, sulfetos e possivelmente carbonato de ferro.
146

Abordagens para o problema de dimensionamento e sequenciamento da produção em indústrias integradas de papel e celulose / Approaches for the lot sizing and scheduling problem in integrated pulp and paper mills

Furlan, Marcos Mansano 10 December 2015 (has links)
O setor industrial produtor de papel e celulose tem aumentado sua relevância comercial nas últimas décadas devido à demanda constantemente crescente. O aumento na competitividade do setor gerado pela economia globalizada e a dificuldade de desenvolvimento de bons planos de produção em ambientes produtivos cada vez mais complexos têm motivado a pesquisa por novas e efetivas ferramentas de auxílio à tomada de decisão. Considerando estas dificuldades, abordamos neste trabalho o problema de dimensionamento e sequenciamento de lotes com foco em empresas com processo integrado de produção de celulose e de papel. Trata-se de um problema de planejamento de médio a curto prazo, geralmente com maior enfoque no curto prazo por considerar o planejamento detalhado da produção em horizontes de planejamento que não superam 30 dias. No processo integrado de celulose e papel, foram consideradas as decisões de produção do digestor, evaporador, caldeira de recuperação e de múltiplas máquinas produtoras de papel, além do controle de estoque de produtos intermediários e finais. Modelos matemáticos da literatura foram modificados e estendidos para incorporar características adicionais do problema como, por exemplo, processos com múltiplas máquinas de papel. Além disso, foram desenvolvidas heurísticas construtivas, heurísticas de melhoria, abordagens de solução híbridas baseadas em algoritmos genéticos combinadas com ferramentas comerciais de solução exata, além de combinações entre os métodos. As abordagens desenvolvidas foram testadas computacionalmente e as melhores combinações de métodos foram definidas. De forma geral, os resultados dessas abordagens foram superiores aos obtidos por ferramentas de solução comerciais puras. Ademais, a variação proposta da heurística de melhoria fixe-e-otimize com mudanças na função objetivo se destacou com relação aos demais métodos, obtendo os melhores resultados, independentemente da qualidade da solução inicial utilizada. As principais contribuições desta tese são a apresentação de modelos matemáticos para representar apropriadamente o problema estudado, e o desenvolvimento de métodos de solução efetivos para resolver o problema. / The pulp and paper industry has been increasing the commercial importance in recent decades due to the constant growing demand. The increasing competitiveness of this sector generated by the globalized economy and the difficulty to develop good production plans in complex production environments have motivated the search for new and effective decision support systems. Given these difficulties, in this thesis we address the lot sizing and scheduling problem focused on integrated pulp and paper mills. This is a problem of medium to short term planning, generally more focused on the short term as it covers detailed production schedules in planning horizons which do not exceed 30 days. In these integrated pulp and paper process the production decisions of digester, evaporator, recovery boiler and multiple paper machines are considered, apart from the inventory control of intermediate and final products. Mathematical models known in the literature were modified and extended to incorporate additional features of the problem, such as processes with multiple paper machines. In addition, constructive and improvement heuristics, and hybrid methods based on genetic algorithms combined with a commercial solver were developed, as well as combinations of these solution approaches. The methods developed were computationally tested and the best combinations of methods were defined. Overall, the results of these methods were superior to the solutions obtained by pure commercial solvers. Moreover, the alternative variation proposed of the improvement heuristic fix-and-optimize with exchanges in the objective function surpassed the other methods, obtaining the best results, regardless of the quality of the initial solution used. The main contribution of this thesis are the presentation of mathematical models that appropriately represents the problem under study, and the development of effective solution methods to deal with the problem.
147

Influence of acid hydrogen peroxide treatment on refining energy and TMP properties

Walter, Karin January 2009 (has links)
<p>The potential of using acid hydrogen peroxide under Fenton conditions to lower the electrical energy consumed during the production of Black spruce (Picea mariana) thermomechanical pulp (TMP) was investigated. The chemical system, which consisted of ferrous sulphate, hydrogen peroxide and optionally an enhancer (3,4-dimethoxybenzyl alcohol, ethylenediaminetetraacetic acid or oxalic acid/sodium oxalate), was evaluated as an inter-stage treatment where the primary refiner was used as a mixer. The produced TMPs were thoroughly characterised in order to explain the effect of the chemical system on fibre development and to be able to propose a mechanism for the impact on refining energy reduction. The possibility to improve the optical properties by washing, chelating and sodium dithionite or hydrogen peroxide bleaching the treated pulps was evaluated.</p><p> </p><p>The results obtained in a pilot plant trial show that it is possible to significantly reduce the comparative specific energy consumption by approximately 20% and 35% at a freeness value of 100 ml CSF or a tensile index of 45 Nm/g by using 1% and 2% hydrogen peroxide respectively. The energy reduction is obtained without any substantial change in the fractional composition of the pulp, though tear strength is slightly reduced, as are brightness and pulp yield. No major differences between the reference pulp and the chemically treated pulps were found with respect to fibre length, width or cross-sectional dimensions. However, the acid hydrogen peroxide-treated pulps tend to have more collapsed fibres, higher flexibility, a larger specific surface area and a lower coarseness value. The yield loss accompanying the treatment is mainly a consequence of degraded hemicelluloses. It was also found that the total charge of the chemically treated pulps is higher compared to the reference pulps, something that may have influenced the softening behaviour of the fibre wall.</p><p> </p><p>A washing or chelating procedure can reduce the metal ion content of the chemically treated TMPs considerably. The amount of iron can be further reduced to a level similar to that of untreated pulps by performing a reducing agent-assisted chelating stage (QY) with dithionite. The discoloration cannot, however, be completely eliminated. The brightness decrease of the treated pulps is thus not only caused by higher iron content in the pulp, but is also dependent on the type of iron compound and/or other coloured compounds connected with the acid hydrogen peroxide treatment. Oxidative bleaching with hydrogen peroxide (P) is more effective than reductive bleaching with sodium dithionite in regaining the brightness lost during the energy reductive treatment. Using a QY P sequence, a hydrogen peroxide charge of 3.8% was needed to reach an ISO brightness of 75% for the chemically treated pulps. The corresponding hydrogen peroxide charge for the untreated TMP reference was 2.5%.</p><p> </p><p>The radicals generated in the Fenton reaction will probably attack and weaken/soften the available outer fibre wall layers. This could facilitate fibre development and consequently lower the electrical energy demand for a certain degree of refinement.</p>
148

Influence of acid hydrogen peroxide treatment on refining energy and TMP properties

Walter, Karin January 2009 (has links)
The potential of using acid hydrogen peroxide under Fenton conditions to lower the electrical energy consumed during the production of Black spruce (Picea mariana) thermomechanical pulp (TMP) was investigated. The chemical system, which consisted of ferrous sulphate, hydrogen peroxide and optionally an enhancer (3,4-dimethoxybenzyl alcohol, ethylenediaminetetraacetic acid or oxalic acid/sodium oxalate), was evaluated as an inter-stage treatment where the primary refiner was used as a mixer. The produced TMPs were thoroughly characterised in order to explain the effect of the chemical system on fibre development and to be able to propose a mechanism for the impact on refining energy reduction. The possibility to improve the optical properties by washing, chelating and sodium dithionite or hydrogen peroxide bleaching the treated pulps was evaluated.   The results obtained in a pilot plant trial show that it is possible to significantly reduce the comparative specific energy consumption by approximately 20% and 35% at a freeness value of 100 ml CSF or a tensile index of 45 Nm/g by using 1% and 2% hydrogen peroxide respectively. The energy reduction is obtained without any substantial change in the fractional composition of the pulp, though tear strength is slightly reduced, as are brightness and pulp yield. No major differences between the reference pulp and the chemically treated pulps were found with respect to fibre length, width or cross-sectional dimensions. However, the acid hydrogen peroxide-treated pulps tend to have more collapsed fibres, higher flexibility, a larger specific surface area and a lower coarseness value. The yield loss accompanying the treatment is mainly a consequence of degraded hemicelluloses. It was also found that the total charge of the chemically treated pulps is higher compared to the reference pulps, something that may have influenced the softening behaviour of the fibre wall.   A washing or chelating procedure can reduce the metal ion content of the chemically treated TMPs considerably. The amount of iron can be further reduced to a level similar to that of untreated pulps by performing a reducing agent-assisted chelating stage (QY) with dithionite. The discoloration cannot, however, be completely eliminated. The brightness decrease of the treated pulps is thus not only caused by higher iron content in the pulp, but is also dependent on the type of iron compound and/or other coloured compounds connected with the acid hydrogen peroxide treatment. Oxidative bleaching with hydrogen peroxide (P) is more effective than reductive bleaching with sodium dithionite in regaining the brightness lost during the energy reductive treatment. Using a QY P sequence, a hydrogen peroxide charge of 3.8% was needed to reach an ISO brightness of 75% for the chemically treated pulps. The corresponding hydrogen peroxide charge for the untreated TMP reference was 2.5%.   The radicals generated in the Fenton reaction will probably attack and weaken/soften the available outer fibre wall layers. This could facilitate fibre development and consequently lower the electrical energy demand for a certain degree of refinement.
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Three essays on evolving regulatory climates and market adjustment strategies

Urmanbetova, Asel 21 September 2015 (has links)
This dissertation consists of three empirical analyses examining the interactive and evolving nature of government regulations and how the regulated industries respond to the changes in the regulatory climate. Using the U.S. pulp and paper mills as an example, the three essays bring together a number of strands of literature in environmental economics and policy studies discussing how changes in the U.S. environmental policy are shaped by industry concerns and which strategies firms choose in order to adjust to the changes in policy. Essay 1 examines if, in addition to the standard input factors, indirect costs associated with tax and environmental policies affect papermakers’ ‘stay put’ investment decisions. The findings suggest that state environmental stringency has a negative impact on investments, but it is statistically insignificant and higher taxes do not deter investments. The Essay 2 studies whether voluntary abatement and prevention efforts at pulp and paper mills affects regulatory stringency they face. The analysis tests the hypotheses of ‘responsive regulation’ and whether regulators are driven by numerical pollution targets or budgetary constraints. The findings suggest that voluntary pollution abatement and prevention have greater impact on regulatory stringency than government budgets. Finally, Essay 3 analyzes the relationship between pollution prevention (P2) policy instruments and adoption of P2 modifications. The study tests the hypotheses of whether P2 policy instruments have positive impact on P2 adoptions. The results suggest that the policy instruments have different effects on different types of P2 modifications and that regulatory and political threat is a strong predictor of P2 adoptions.
150

Newswire

Vice President Research, Office of the 11 1900 (has links)
Three UBC researchers have been awarded the 2007 NSERC Synergy Award for Innovation. A development of advanced pulp screen rotors that employ innovative energy-saving technology has garnered a 2007 NSERC Synergy Award. The 2007 Leo Derikx Award from the NSERC Synergy Awards has been awarded to UBC's Mineral Deposit Research Unit. A UBC collaboration with Weyerhaeuser, an international forest products company, and Paprican, the Pulp and Paper Research Insittute of Canada, is among the recipients of a 2007 NSERC Synergy Award for Innovation.

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