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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.
71

A revision of the first three phases in the European Union’s ETS and its effects on the CO2 emissions within the Swedish and Finnish Pulp & Paper industry.

Blanking, Oscar, Stålberg, Samuel January 2023 (has links)
The European Emissions Trading Scheme (EU ETS) aims to lower greenhouse gases inpollution-intensive industries. The success of the EU ETS, its policy framework and its pricingstrategy is both empirically acknowledged and disputed. The study contributes to the empiricalresearch on the effect of the price of EU ETS permits on carbon emissions. Therefore, the aimis to establish the relationship between the price of emission permits and CO2 emissions inrelation to each phase of the EU ETS, for Sweden and Finland with a focus on the Pulp andPaper Industry (PPI). Moreover, the focus lies on the difference in the effect of each EU ETSphase on CO2 emissions, allowing for discussion on the effectiveness of each phase. Using aNewey-West multiple linear regression analysis, we found statistically significant evidence thatduring Phase 3, EU ETS permit pricing had a negative effect on CO2 emissions for both Swedenand Finland, EU ETS permit pricing in Phase 1 seems to have a low positive effect on CO2emissions solely for Sweden, while Phase 2 does not have an effect on CO2 emissions for eithercountry. Our collected data implies some degree of ineffectiveness and uncertainty in thesuccess of the EU ETS framework and pricing strategy.
72

Industrial Demand Response in the Primary Reserve Markets : A case study on Holmen’s Pulp and Paper Mill

Tomasini, Federica January 2019 (has links)
This thesis stems from the interest of Holmen group to investigate the opportunitiesavailable for large electricity consumers in the Swedish primary reserve markets.The study performed focuses on one of Holmen's paper mill and it aims at identifyinga load inside the production process that is suitable for providing frequency containmentservices for the grid. The evaluation of the mill's consumption prole and the technicalrequirements of the reserve market led to the identication of the electric boiler coupledwith a steam accumulator as the most appropriate load.Five case study simulating the participation of the mill to dierent energy and reservemarkets have been evaluated. For each case a linear optimization problem has beenformulated. The rst simulation represents the current practice of the mill in relation tothe energy purchased on the spot market (following it will be also referred as referencecase). The second case study (II c.s.) integrates the use of the steam accumulator asa tool to perform thermal load shifting. In the third case study (III c.s.) the mill ismodelled to bid on the spot and primary reserve market by oering some capacity ofthe electric boiler. The last two case studies (IV and V c.s.) recalls the rst and lastpreviously mentioned, but also include the possibility of having energy imbalance. Thismeans that the imbalance settlement operated by eSett will produce an additional costor prot for the mill.The last three problem formulations fall under the denition of stochastic problems,since two random variable are present, namely: average hourly frequency value andimbalance settlement price. The uncertainty of the variables is represented throughscenarios.The outcome derived from the combination of the results for the winter and summercases shows that each strategy brings an economic saving when compared to the referencecase (I c.s.). The less interesting strategies are the ones that do not involve the reservemarket, leading to about 0.03% (II c.s.) and 0.06% (IV c.s.) of saving on the overallyearly energy cost. Contrariwise, by oering FCR-N capacity, the cost of electricitycan be cut by 5.15% (III c.s.) and 6.69% (V c.s.), respectively considering and notconsidering the imbalance settlement. / Avhandlingen har sitt ursprung i skogsindustrikoncernen Holmens intresse att undersökamöjligheten för stora elförbrukare att delta på den svenska primär-reservmarknaden. Studien som utförts fokuserar på ett av Holmens pappersbruk och syftar till att identifiera en elektrisk process som, inom bruksgränserna, är lämplig för att tillhandahålla frekvensregleringstjänster till det nationella nätet. En utvärdering av brukets elförbrukning samt de tekniska krav som ställs på reservmarknaden ledde till att en elektrisk panna med tillkopplad ångackumulator identifierades som mest lämplig.Fem budstrategier som simulerar brukets deltagande till olika energioch reservmarknader har presenterats. För varje strategi är ett linjärt optimeringsproblem formulerat. Den första strategin visar på nuvarande sätt bruket köper elektricitet på spotmarknaden. Den andra strategin integrerar användning av ångackumulatorn som ett verktyg för att utföra termisk lastskiftning. I den tredje modelleras deltagande också på primärreservmarknaden genom att erbjuda en viss kapacitet hos elpannan. De två sista strategierna baseras på den första och tredje, men tillåter i tillägg obalanser vilket innebär en extra kostnad eller möjlig intjäning för bruket.De tre sista problemformuleringarna faller under definitionen stokastiska problem, eftersom två slumpmässiga variabler är närvarande, nämligen: genomsnittligt timfrekvensvärde och priset för obalans. Osäkerheten för variablerna representeras genom scenarier.Resultatet visar att varje strategi ger en ekonomisk besparing jämfört med refer-ensfallet (strategi ett). De mindre intressanta strategierna är de som inte involverarreservmarknaden, vilka endast leder till ca 0,03% och 0,06% minskning av den totalaårliga energikostnaden. Däremot, genom att erbjuda FCR-N-kapacitet kan kostnaden för el minskas med 6,69% och 5,15% beroende s eller ej.
73

Produktion av flyktiga fettsyror genom anaerobisk rötning av pappersmassa och papperslam / Production of volatile fatty acids from pulp and paper sludge

Lara, Abdla January 2022 (has links)
Recently, there has been an increased interest in the production of volatile fatty acids from pulp and paper sludge using an immersed membrane bioreactor during anaerobic digestion. The production of biogas through anaerobic digestion has been a hot topic in recent years, but it is no longer economically viable due to competition from fossil fuels. As a result, the production of volatile fatty acids has been investigated in this study using pulp and paper sludge as substrate. To investigate the effect of methane inhibition on enhanced volatile fatty acid production, various parameters, and pre-treatments such as pH, O2 presence, thermal heat shock, and chemical BES-addition were used. Heat shock pre-treatment produced the most volatile fatty acids (2.4 g/L) while producing the least methane (50 mL/g VS). The immersed membrane bioreactor was successfully used to produce volatile fatty acids for 54 days. / En av dagens problem är den ökade populationen vilket har lett till ökade mängder av avfall från mat och slam. Innan låg ett stort fokus på att använda dessa rester i en anaerobisk rötning för att producera biogas. Dock har detta visat sig att inte vara ekonomiskt hållbart just på grund av att inte kunna konkurrera med fossila bränslen, därför har man i stället fokuserat på att ta fram de intermediära produkterna från rötning processen, dvs flyktiga fettsyror. Detta projekt har fokuserat på att producera flyktiga fettsyror från pappersmassa och papperslam som är potentiellt lättare nedbrytbart, än andra lignocellulosa rika substrat. När man vill maximera flyktiga fettsyraproduktionen, då är det viktigt att samtidigt förhindra produktion av biogas. Effekten av flera olika parametrar, såsom närvaro av syre, pH, för behandling med värmechockeller BES-tillsats, för att inhibera produktion av metan har därför undersökts. Förbehandlingen med värmechock ledde till runt 2,4g/L fettsyraproduktion, tillsammans med den minsta mängden av metan, runt 50 mL/gVS. Membranreaktorn kunde användes framgångsrikt för kontinuerlig produktion av flyktiga fettsyror under 54 dagar.
74

Application of Ozone in Dissolved Air Flotation (DAF) for Enhanced Removal of TOC and Suspended Solids in Pulp and Paper Wastewaters

Brown, Amy Patricia January 2016 (has links)
Pulp and paper mills are one of the top consumers of water related to industrial manufacturing, which ultimately leads to a large volume of heavily contaminated wastewater. This discharged effluent can have a harmful effect on the receiving aquatic environment and cause further ramifications downstream. Thus, a technically feasible and cost effective treatment solution for safe release from the mill is essential. Dissolved air flotation (DAF) has many applications and involves the formation of air microbubbles triggered by a drop to atmospheric pressure. When introduced into the wastewater, these microbubbles attach to the floc particles present and float to the surface. Another water treatment technology is ozone, a powerful oxidant, and has been widely used in water and wastewater treatment over recent decades, including color reduction in pulp and paper mill wastewater treatment. This thesis studied the effect pre-ozonation has on the DAF process in treating pulp and paper mill secondary effluent. Wastewaters from three mills with different initial water quality parameters were used, especially chemical oxygen demand (COD), turbidity, and color. The most suitable coagulant and coagulant aid, aluminum chlorohydrate and cationic polymer NS 4700P respectively, were selected, and an effective bench-scale experimental procedure was established. Pre-ozonation did not reduce the need for coagulant due to little change in the overall COD, color, or turbidity removal. However, ozonation did reduce color before coagulation, and the ultimate target removal of COD to 90 ppm was met with the conditions chosen. / Environmental Engineering
75

Adhesives with Controllable Degradability for Wet Cellulosic Materials / Degradable Cellulose Wet Adhesives

Yang, Dong January 2018 (has links)
Cellulose wet adhesives are applied to enhance the wet strength of paper products by binding individual paper fibers together. However, the recycling of the wet strength paper is a challenge as the fibers are hard to re-disperse in water. This project demonstrates new strategies for developing cellulose wet adhesives with controllable degradability, facilitating the recycling of wet strength papers. In this project, regenerated cellulose membranes were used to simulate paper fibers. In adhesion measurements, two wet cellulose membranes were laminated with a thin layer of adhesive (1–30 mg/m2), and the 90-degree wet-peel was used as a measure of cellulose wet adhesion. It was shown that the wet-peel was a simple and reliable method to evaluate the wet adhesives for paper products. Cellulose wet adhesives, in the form of microgels or linear polymers, were synthesized by incorporation of hydrazide, amine or azetidinium functional groups that can form covalent bonds to cellulose surfaces. Two strategies to design degradable adhesives were demonstrated in this project. 1) Reductant-responsive microgel adhesives were created by introducing cleavable disulfide linkages, either in the polymer chains tethering adhesive groups or as the microgel crosslinks. More than 70% reduction in wet adhesion was achieved after exposure to a reductant. 2) Degradable polymer cohesive bonds were used to “switch off” the cellulose wet adhesion. This adhesive was created by introducing labile boronate-dextran complexes to the PVAm adhesive layer between cellulose surfaces. The introduction of this new interaction between PVAm chains enhanced the cellulose wet adhesion. In response to subtle pH changes or the presence of monosaccharides, the wet adhesion decreased by 60%. / Thesis / Doctor of Philosophy (PhD) / Wet strength is important for paper products such as paper towels and paper packaging. In paper manufacturing, cellulose wet adhesives are applied to enhance the strength of wet papers by “gluing” together individual cellulose fibers. However, the recycling of wet strength papers is a challenge because the current adhesives prevent the easy disintegration of waste paper back to a suspension of discrete cellulose fibers. As an important part of the bio-based economy, the next generation of paper products are required to be both strong in water and easy to recycle. This thesis explores new designs for wet-strength adhesives that will facilitate recycling. Both nanoparticles and linear polymers were synthesized in this study as cellulose wet adhesives. Many important properties of wet adhesives were probed, including the size of nanoparticles, the pre-treatment of cellulose surfaces, the dosage of adhesives and the choice of adhesive chemistries. A few types of novel cellulose wet adhesives with controllable degradability were synthesized and evaluated. I demonstrated that the cellulose wet adhesion can be “switched off” in response to subtle pH changes, reducing agents or sugars, showing a promising start for the recycling of wet strength papers.
76

Analysis and Prevention of Usable Fiber Loss from a Fine Paper Mill

Barber, Steven Donald 08 October 1998 (has links)
Reducing losses of usable waste fiber from paper mills conserves valuable resources and has the capacity to produce considerable economic returns to the manufacturer. The purpose of this research effort was to evaluate the potential for the prevention of loss and/or recovery of usable waste fiber from paper machines within a fine paper mill. Further, a preliminary evaluation of fiber loss prevention strategies and fiber recovery technologies was conducted. The paper mill in question experienced losses of usable waste fiber to the sewer in amounts approaching, and sometimes exceeding 40 tons/day. An existing database of usable fiber test results was analyzed to determine patterns of fiber loss. Further testing showed that the most significant fiber losses resulted from centrifugal cleaner cones. These cones, designed to remove foreign material from stock, are one step in a series of mechanical cleaning devices in the stock preparation area of the paper mill. Cleaner cone systems on two of the paper machines were found to contribute most significantly to total fiber loss. Contrary to cleaner cone design, the dirt content of fiber rejects from cones experiencing excessive loss was very low. Cleaner cones on other machines operated normally. These rejects were extremely dirty and quantities of fiber were low. These results indicate poor operating efficiency of two of the cleaner cone systems in question. By adding cones where space is available, system capacity and efficiency will increase, fiber losses will decrease, and the dirt content of rejects will increase. This will result in substantial resource and financial savings to the paper mill. Technologies have been developed to recover usable fiber from paper mill sludge. However, prior to further investigation of the use of such innovations at this paper mill, efforts should focus on the reduction of fiber loss from point sources. / Master of Science
77

Närsaltsdosering till luftad damm : en åtgärd för ökad TOC-reduktion hos Skoghalls Bruk luftade damm / Dosage of nutrient to an aerated lagoon : a measure to a higher TOC-reducation to the aerated lagoon of Skoghall Mill

Bonde, Carl January 2006 (has links)
<p>In the process of making carton boards into Skoghall Mill, are great quantities of water being contaminated. This water has to be treated before it is possible to release into the recipient, Kattfjorden. One of the contaminations that is important to extract from the wastewater, is organic carbon (measured as TOC-total organic carbon) because microbiological breakdown can lead to the bottom becomig free of oxygen.</p><p>The wastewater treatment at Skoghall Mill is done through an external wastewater treatment that is located at the factory. The biological treatment (aerated lagoon) is a 140 000 m3 water pool with surface aerator, which is give oxygen to the water. In the lagoon live microorganisms who performs the biggest part of the TOC-reduction.</p><p>One problem with the lagoon is that the treatment of TOC is considerably worse during wintertime than during summertime. The reduction is during wintertime only 40 %, while during summertime it is about 70-80 %. This seasonal variation can to a large extent be explained by, that the water temperature in the lagoon decreases wintertime. The low water temperature does that the biological activity in the lagoon is reduced, which reduces the TOC-reduction. A second reason can also be that the microorganisms do not have enough bioavailable nutrients that is needed for growth of a new biomass.</p><p>In this thesis the need of nutrient has been examined. In two test pools, addings of nutrient were being done, to come to the conclusion of a good dosage of nutrient which would lead to a larger reduction of TOC, without enlarged quantities of nitrogen/phosphorus in the outgoing water. One of the test pools hold a summer temperature (30°C), and the other test pool hold a winter temperature (10°C). The test was performed this way to see if there would be any difference in the need of nutrient between summertime and wintertime.</p><p>The most important conclusion was that a nutrient dosage to the Skoghall aerated lagoon, rise the TOC-reduction wintertime. It was also concluded that it was foremost the nitrogen that contributed to the raised TOC-reduction, and nitrogen is thereby considered to be the growth restraining element wintertime. It seemed like phosphorus had been overdosed during the tests, while enlarged halts of the substance could be seen in the outgoing water, and an optimal dosage of phosphorus could not be done. The recommendation that came as a results from the tests, was that during wintertime add nitrogen and phosphorus according to TOC:N:P-quota 100:0,75:0,10. To the summer pool was no considerable improvement of the TOC-reduction seen, as a result of the nutrient addings. It is also no reason to dosage nutrients in summertime.</p> / <p>Vid tillverkning av kartong och pappersmassa på Skoghalls Bruk förorenas stora mängder vatten, som därmed måste renas före utsläpp till recipienten, Kattfjorden, en vik i Vänern. En av de föroreningar som är viktig att avlägsna ur avloppsvattnet är organiska kolföreningar (TOC-total organic carbon) eftersom det vid mikrobiologisk nedbrytning av TOC åtgår syre vilket kan leda till att sjöbotten blir syrefri.</p><p>Rening av avloppsvatten på Skoghall Bruk sker genom en extern reningsanläggning som är placerad på bruket. Det biologiska reningssteget i reningsanläggningen är en s.k. luftad damm. Detta är en 140 000 m3 stor vattenbassäng med ytluftare som syresätter vattnet. I dammen lever mikroorganismer vilka utför den största delen av TOC-reduktionen i brukets reningsanläggning.</p><p>Ett problem med dammen är att reningen av TOC är betydligt sämre vintertid än sommartid. Reduktionen av det till dammen inkommande TOC, är vintertid endast ca 40 % medan den sommartid ligger kring 70-80 %. Denna årstidsvariation kan till stor del förklaras av att vattentemperaturen i dammen sjunker vintertid. Den låga temperaturen medför att den biologiska aktiviteten i dammen sjunker, vilket hämmar TOC-reduktionen. En annan orsak till en låg TOC-reduktion kan vara att det för mikroorganismerna råder brist på biotillgängliga närsalter (kväve och fosfor) som behövs för tillväxt av ny biomassa.</p><p>I detta examensarbete har det undersökts behovet av närsalter för att höja TOC-reduktionen. I två laborationsdammar (ca 20 l) skedde doseringar av närsalter i syfte att finna en bra doseringskvot som innebar en ökad reduktion av TOC, utan att det blev förhöjda kväve-/fosforhalter i utgående vatten. En av laborationsdammarna höll sommartemperatur (ca 30°C) och en höll vintertemperatur (ca 10°C) vilket gjordes för att undersöka om det var skillnad av närsaltsbehovet mellan sommar och vintertid.</p><p>Den viktigaste slutsatsen av försöken var att en närsaltsdosering till Skoghalls luftade damm höjer TOC-reduktion vintertid. Det konstaterades att det var kvävet som främst bidrog till den ökade TOC-reduktionen och kväve anses därmed vara det tillväxtbegränsande ämnet vintertid. Fosfor tycktes ha överdoserats under försöken, då det sågs förhöjda halter i utgående vatten, och en optimal dosering av fosfor kunde inte avgöras. Den rekommendation som föll ut av de laborativa försöken var att vintertid dosera kväve och fosfor enligt TOC:N:P-kvot 100:0,75:0,10. Till sommardammen sågs inte någon förbättring av TOC-reduktionen till följd av närsaltstillsatserna, vilket innebär att närsaltsdoseringar sommartid är obefogat. Vidare sågs tendenser till att slammets sedimentationsegenskaper, hos framförallt vinterdammen, blev bättre till följd av närsaltsdosering, men brist på mätdata medför att det är svårt att dra slutsatser om det verkligen varit så.</p>
78

Development of a Free Lime Monitoring System for the Kraft Recovery Process using Zeta Potential

Ren, Wei 04 July 2014 (has links)
The presence of Ca(OH)2 (or free lime) in lime mud can cause many problems in the recovery process of kraft pulp mills. Conventional free lime analyses require extensive laboratory work and give inconsistent results. A systematic study was performed to determine if zeta potential, a quickly measurable dispersion characteristic, can be used to indicate the presence of free lime in the recovery process. Measurements were made on synthetic wet lime mud to simulate samples collected after the white liquor clarifier in pulp mills. The results show that zeta potential increases from negative to positive when the free lime content in the lime mud exceeds a critical threshold. This change from negative to positive zeta potential of the lime mud slurry can be used as a basis for developing an on-line monitoring system that effectively detects free lime in the lime mud in order to avoid problems associated with overliming in the recovery process.
79

Configuração, reestruturação e mercado de trabalho do setor de celulose e papel no Brasil / Configuration, restructuring and marketplace of pulp and paper sector in Brazil

Montebello, Adriana Estela Sanjuan 25 October 2010 (has links)
A presente tese analisa a configuração, a reestruturação e a dinâmica do setor de celulose e papel no Brasil (em especial o seu mercado de trabalho), mostrando que esses processos foram distintos para as indústrias desse setor, que são: a indústria de celulose, a indústria de papéis e a indústria de artefatos de papéis. A tese está organizada em quatro capítulos, incluindo a Introdução. O segundo capítulo, Análise do processo de configuração do setor de celulose e papel no Brasil, destaca como a conduta das empresas multinacionais, as políticas públicas e o dinamismo dos mercados doméstico e externo geram evoluções e dinâmicas distintas para as indústrias desse setor, desde sua origem até 2009, e implicaram em suas distintas inserções na Divisão Internacional do Trabalho - DIT ao longo do tempo. Demonstra-se que a configuração dessas indústrias foi diferenciada nos últimos cinquenta anos, sendo que a expansão da indústria de celulose foi para atender o mercado internacional e as indústrias de papéis e artefatos de papéis são mais centralizadas em atender o mercado doméstico em resposta à forma como os países se organizaram dentro da DIT. O terceiro capítulo, Impactos da reestruturação do setor de celulose e papel no Brasil sobre o desempenho de suas indústrias, usou dados em painel e estimou equações visando identificar se as variáveis de estrutura e de abertura comercial tiveram influência sobre o desempenho das indústrias do setor no período de 1986 a 2007 com base nos dados da PIA IBGE, da BRACELPA e do Sistema ALICE-Web. Pode-se concluir que a variável de concentração de mercado (HHI) teve impacto positivo sobre a medida de desempenho margem preço-custo; o aumento na taxa de importação tem relação negativa com a margem preço-custo; e a origem do capital tem relação positiva com a medida de desempenho considerada. O quarto artigo, Impactos da liberalização comercial e da reestruturação industrial sobre o mercado de trabalho do setor de celulose e papel no Brasil, analisa a dinâmica do mercado de trabalho desse setor entre 1996 e 2008 usando dados da RAIS. Verificou-se: 1) aumento no número de empregados no setor de celulose e papel nesse período, mas redução desse número para a indústria de celulose e para a indústria de papéis; 2) a indústria de celulose emprega proporcionalmente mais trabalhadores com maior escolaridade e idade do que a indústria de artefatos de papéis; 3) os salários pagos na indústria de celulose foram maiores que nas outras duas indústrias e no setor de celulose e papel como um todo; 4) predomínio do uso da mão de obra masculina e diferencial salarial entre homens e mulheres nas três indústrias, entretanto, esse diferencial foi menor na indústria de celulose em 2008; 5) a maioria das variáveis explicativas propostas para analisar o impacto sobre os salários apresentou o sinal esperado nas regressões. As variáveis abertura comercial, proporção de mulheres em relação aos homens e escolaridade média dos trabalhadores foram as que apresentaram melhor significância estatística. As duas primeiras atuam para reduzir o salário e a última para aumentá-lo. / The present thesis analyzes the configuration, the restructuring and the dynamics of the pulp and paper sector in Brazil (paying a special attention to its labor market), showing that these processes were different to the industries of this sector: the industry of pulp, industry of papers and industry of paper-made products. The thesis is organized in four chapters, including the Introduction. The second, Analysis of configuration process of pulp and paper sector in Brazil, highlights how the conduct of multinational companies, the public policies and the dynamism of domestic and external markets generate distinct evolutions and dynamics for the three industries inside the pulp and paper sector in Brazil since the origin of this sector until 2009 and implicated in distinct insertions of these industries in the International Work Division - DIT along time. It is demonstrated that the configuration of these industries was differentiated during the last fifty years, pointing out the expansion of pulp industry, from 1970 on, to attend the international market and the paper and paper artifacts industries are more focused in attending the domestic market in response to the way the countries organized themselves inside DIT. The third chapter, Impacts of pulp and paper sector´s restructuring in Brazil on the performance of its industries, organized data in panel and run equation to determine if the variables of structure and commercial openness that had influence the performance of industries under analysis. The period of time considered was from 1986 to 2007 and data utilized came from PIA IBGE, from BRACELPA and from Alice-Web System. It can be concluded that the variable of market concentration (HHI) had positive impact on the performance measure cost-price margin; the increase in the importation rate has negative relation with price-cost margin; and the capital´s origin has positive relation with the performance measure considered. The fourth chapter, Impacts of trade liberalization and industrial reorganization the market place of pulp and paper sector in Brazil, analyses the labor market dynamics of this sector between 1996 and 2008 using data from RAIS. The main findings are: 1) increase in the number of employees of the pulp and paper sector in this period, but reduction of this number to the pulp industry and to the paper industry; 2) the pulp industry employs proportionally more workers with higher scholarity and age than the paper-made products industry; 3) salaries paid in the pulp industry were higher than in the other two industries and in the pulp and paper sector as a whole; 4) predominance of masculine labor force and salary differential between men and women in the three industries, however, this differential was lower in the pulp industry in 2008; 5) the majority of the explicative variables proposed to analyze the impact on the salaries presented the expected signal in regressions. The variables commercial openness, proportion of women in relation to men and workers average scholarity were the ones that presented better statistic significance. The first two act to reduce salaries and the third one to increase salaries.
80

Influência do valor da madeira de mercado sobre o ordenamento de florestas plantadas para o suprimento parcial de uma indústria de celulose e papel: uma aplicação da programação linear. / Influence of the market wood value on the management of planted forests partially supplying a pulp mill: an application of linear programming.

Brun, Fábio Luís 11 April 2002 (has links)
De maneira geral, o abastecimento de madeira de indústrias de celulose brasileiras provém de áreas plantadas próprias e de madeira comprada no mercado. Programas de planejamento florestal de longo prazo procuram, normalmente, abranger o manejo da floresta plantada de forma dissociada à aquisição de madeira de fontes externas. O objetivo deste estudo é avaliar o impacto da variação de valores de aquisição da madeira de mercado em modelos de programação linear que consideram seu volume adquirido como uma das variáveis-resposta. Fundamentado em dados florestais de 155 Unidades de Produção fornecidos pela International Paper do Brasil Ltda., empresa do ramo de papel para imprimir e escrever situada em Mogi-Guaçu, Estado de São Paulo, o trabalho apresenta resultados provenientes da geração de 80 modelos de programação linear submetidos a cinco diferentes cenários de valores de madeira de mercado. As abordagens dos modelos foram divididas em: modelos de maximização do valor presente líquido e modelos de minimização do valor do custo presente, subdivididos em modelos Global e Regionalizado (procurando observar uma condicionante administrativa da empresa), ordenados ou de produção livre e, finalmente, submetidos ou não a restrições operacionais de área máxima de colheita. Os resultados permitem observar que as diferentes abordagens de planejamento possuem graus variados de sensibilidade a variações de valores de madeira de mercado, notadamente os modelos de minimização do valor presente do custo. Esta sensibilidade pode ser medida pelas variações provocadas nos programas de colheita de madeira própria e compra de madeira de mercado, pela flutuação das idades médias de colheita, pelos resultados das funções-objetivo e pelo percentual de aproveitamento de área própria. Os dados também sugerem que há vantagem em manejar a floresta pelo modelo Global, que desconsidera os limites administrativos da empresa. Também, pode-se afirmar que a maximização do valor presente líquido das prescrições é a abordagem preferível em função de demonstrar maior robustez na geração de planos de manejo menos sensíveis aos diferentes cenários de valor da madeira de mercado. / Generally, the Brazilian pulp industry wood supply is largely provided by planted forests owned by the companies and wood purchased in the market. Long term planning programs usually address the two supplying sources - fee forests and market wood -separately. The main objective of this study is to assess the impact of different wood acquisition value scenarios in linear programming models that consider the amount of purchased wood as one of the variables. Based on data of 155 Production Units supplied by International Paper do Brasil Ltda., a printing paper company located in Mogi-Guaçu, State of São Paulo, the study presents results from the generation of 80 linear programming models submitted to five different wood acquisition value scenarios. The approach was divided into: maximization of net present value and minimization of the present cost, divided into Global and Regionalized models (pertaining to a company administrative restriction), with regulated or floating production and submitted or not to operational restrictions as a maximum harvesting area. Results allow observing that the different modeling approaches show different degrees of sensitivity to variations in the wood acquisition value - notably the minimization models. That sensitivity can be measured against variations in the harvesting and wood purchase programs, the floatation of the average harvesting ages, results of the objective function values and the percentage of utilization of fee lands. Results also suggest that there are advantages in managing the forest through the Global model, not considering the actual administrative limitations. Also, the maximization approach is the preferred one once it demonstrates more robustness through the generation of management programs less sensitive to the different proposed wood acquisition value scenarios.

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