• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 19
  • 3
  • 1
  • Tagged with
  • 23
  • 23
  • 21
  • 12
  • 7
  • 6
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 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.
21

Exploration e exploitation na estratégia de diversificação da indústria sucroalcooleira paulista

Santos, Fábia Maria Silva Lins dos 16 August 2007 (has links)
Made available in DSpace on 2016-03-15T19:26:31Z (GMT). No. of bitstreams: 1 Fabia Maria Silva Lins dos Santos.pdf: 2368363 bytes, checksum: b7f60e810f9885e4ab828fa7fb8ba2a0 (MD5) Previous issue date: 2007-08-16 / Fundo Mackenzie de Pesquisa / Traditionally, the sugar cane sector is commodities industry and rarely innovate its portfolio, although researches have shown that some firms inside the sector have been using portfolio diversification strategies in the search of growth. Inside these strategies, the firms have made choices to: prospect new knowledge (exploration) or take advantage of not utilized competencies (exploitation). The use of knowledge is part of sectoral systems of innovation due to actors and institutions interaction. Using an exploratory and multicase and multistrategy study, this project wants to verify which processes exploration or exploitation is predominant on diversification strategy of sugar cane firms. The main contribution of this study are related to three main objectives: (1) identify characteristics of diversification in the sugar cane plants; (2) distinguish the processes of exploration and exploitation in these plants; (3) present evidences that support the presupposition of sugar cane sector being a sectoral systems of innovation. The results have shown that, from a total of nine firms, eight of them developed diversification strategies, related to Penrose (1959) classification of diversification. All of them participated in the sectoral systems of innovation, interacting in major or minor degree. All researched firms presented process related to exploitation, but their punctuation in exploration may explain their search for diversification. The high punctuation at exploration of some firms suggests it may be an explanation of their differentiated portfolio. Furthermore they showed intensive interaction with universities and research entities, in the search for new knowledge. These findings where consistent with the main objective defined in this project. It is expected that the present study might support future researches upon knowledge generation in firms oriented to diversification strategies. / Tradicionalmente, o setor sucroalcooleiro é um produtor de commodities e raramente inova sua carteira de produtos, embora algumas pesquisas demonstrem que firmas dentro do setor têm usado estratégia(s) de diversificação destas carteiras para buscar crescimento. Para atingir esta(s) estratégia(s), as firmas fazem escolhas entre: prospectar conhecimento novo (exploration) ou aproveitar competências não utilizadas (exploitation). O uso do conhecimento é característico dos sistemas setoriais de inovação devido à interação entre seus atores e instituições. Através de um estudo exploratório, mediante a aplicação de estudo multicasos e pesquisa de múltipla estratégia (quantitativa e qualitativa), buscou-se verificar qual dos processos exploration ou exploitation predomina na estratégia de diversificação das firmas sucroalcooleiras. As principais contribuições deste estudo relacionaram-se a três objetivos específicos: (1) identificar características de diversificação presentes nas usinas estudadas; (2) caracterizar os processos de exploration e exploitation nessas usinas; (3) apresentar argumentos que suportem o pressuposto de que o setor sucroalcooleiro é um sistema setorial de inovação. Os resultados apontaram que oito entre nove usinas pesquisadas apresentaram algum tipo de diversificação, de acordo com a classificação de Penrose (1959). Todas as usinas apresentaram participação no sistema setorial em menor ou maior grau e processos voltados à exploitation, mas observou-se que a pontuação em exploration pode ser um fator que explica a busca pela diversificação produtiva. As usinas com valores altos em exploration foram aquelas que apresentaram uma carteira de produtos diferenciada e também nas quais observou-se uma interação maior com universidades e entidades de pesquisa, buscando a prospecção do conhecimento. Espera-se que o presente estudo possa apoiar futuras pesquisas sobre geração de conhecimento em firmas voltadas a estratégias de diversificação.
22

Impacts agronomiques et environnementaux de l'épandage de vinasse et de cendre de charbon/bagasse sur les terres agricoles de l'Île Maurice / Agronomic and environmental impacts of application of coal/bagasse ash and vinasse to sugarcane fields in Mauritius

Soobadar, Aneeza 07 July 2009 (has links)
Des 85 000 hectares de terres agricoles à l’île Maurice, prés de 85% est occupé par la canne à sucre, le reste étant composé de maraîchage et des cultures fruitières. Pour assurer sa pérennité et sa viabilité économique à long terme, l’industrie cannière s’appuie dans son programme de réforme sur une revalorisation de ses sous produits en développant une industrie d’éthanol à partir de la mélasse et en utilisant plus efficacement la bagasse durant la période de récolte pour produire l’électricité. Cependant ces deux filières génèrent beaucoup de déchets (400 000 T/an de vinasse durant la distillation d’éthanol, et 40 000 T/an de la cendre de charbon/bagasse durant la production d’énergie électrique), qu’il faudrait valoriser et gérer avec le moins d’effet néfaste possible sur l’environnement. Parmi les moyens disponibles pour la gestion de ces déchets, le recyclage agricole semble être le plus attrayant du point de vue agronomique et également sous l’aspect de protection de l’environnement. Dans ce contexte pour valider cette pratique de recyclage agricole à l’Île Maurice, une étude a été entreprise pour connaître les effets de l’épandage de fortes doses de vinasse et des cendres de bagasse/charbon sur les sols, la culture de la canne à sucre et sur la qualité des ressources en eau. L’analyse de la vinasse et de la cendre de charbon et de bagasse échantillonnées à intervalle régulier de trois mois entre 2005 et 2008 a montré que leur composition chimique est très variable. Néanmoins la caractérisation de la vinasse a confirmé qu’avec sa teneur en K (moyenne de 9.37 g/L), elle est utile principalement comme engrais potassique quoiqu’à un taux de 100 m3/ha son apport en termes d’azote (moyenne de 122 kg N/ha) et en matière organique (8-15% de matière sèche) sera aussi appréciable. Des métaux lourds (Cu, Zn, Ni, Mn, Pb) étaient également présents dans la vinasse mais leurs concentrations étaient négligeables et ne dépassaient souvent pas la limite de détection du spectrophotomètre d’absorption atomique utilisé pour la mesure (5 mg/kg pour le Cu, Zn, Ni, Pb, 10 mg/Kg pour le Mn) A l’opposé de la vinasse qui est acide (pH de 4.5 en moyenne), la cendre de bagasse ou de charbon possède un pH alcalin variant entre 7.5 à 11.5, et peut de ce fait, être utilisée comme amendement pour corriger l’acidité dans les sols. Appliquée à un taux de 100 T/ha, la cendre de charbon représenterait une source importante de potassium (moyenne de 139 kg K/ha) et surtout de phosphore (moyenne de 298 kg P/ha) à la canne à sucre. Contenant très peu de métaux lourds (Cu, Zn, Ni, Mn, Pb et Hg) et en général pas de micropolluants organiques, la cendre de charbon ne risque pas d’accentuer la présence de ces polluants organiques ou inorganiques dans le sol, dans la canne à sucre ou dans la nappe phréatique. Les études au laboratoire ont par contre démontré que la cendre de bagasse/charbon était capable de fortement immobiliser par adsorption, les herbicides atrazine et hexazinone avec des valeurs de Km (coefficients de sorption) de 0.13 pour atrazine et 0.32 pour hexazinone, rendant minime le risque de transfert de ces herbicides vers la nappe souterraine. Les analyses de sol ont confirmé que l’apport de la vinasse baissait le pH (de 5.9 à 5.4 en moyenne), mais cette baisse n’était que temporaire et pas assez significative pour affecter la croissance de la canne. Le pH du sol retournait à sa valeur initiale peu de temps après l’épandage de 100 m3/ha de la vinasse. La cendre de charbon avait eu un effet inverse en augmentant le pH du sol quoique cette hausse ne fût également pas significative pour la culture de la canne. Epandues à 100 m3/ha et à 100 T/ha la vinasse et la cendre de charbon, respectivement, avaient tendance à hausser la salinité du sol qui restait toutefois bien en dessous du seuil de 1700 RS/cm acceptable pour la culture de la canne à sucre. Si la vinasse à 100 m3/ha augmentait le carbone organique dans certains sols, tel ne fut cependant pas le cas pour la cendre de charbon à 100 T/ha. La vinasse comme la cendre de charbon avait un effet positif sur le niveau de calcium et de magnésium échangeables dans le sol. Ainsi à 100 T/ha la cendre de charbon augmentait dans le sol de Pamplemousses le Ca échangeable de 3.40 à 6.61 cmol+/kg après 12 mois, tandis que durant cette même période la vinasse à 100 m3/ha, et malgré sa forte teneur en potassium, portait le Ca échangeable de 1.66 à 1.83 cmol+/kg dans le sol de Union Park. Les essais aux champs établis dans quatre localités avec des doses croissantes de vinasse (25, 50 et 100 m3/ha) ont montré que le rendement de la canne à sucre que ce soit sous forme de canne ou de sucre n’était pas affecté de façon négative par ce déchet. Au contraire les résultats obtenus durant les trois années d’étude, qui ont permis de récolter une canne vierge et deux repousses, ont démontré que la vinasse avait donné un meilleur rendement en canne (moyenne de 84.9 T/ha annuellement pour les quatre sites) que le traitement recevant NPK uniquement sous forme d’engrais minéraux (moyenne de 77.3 T/ha annuellement pour les quatre sites). Puisque tous les traitements avaient reçu le même taux d’azote et de phosphate, ce rendement plus élevé de la vinasse était A part une meilleure nutrition potassique, probablement dû à une amélioration de la qualité du sol grâce aux matières organiques apportées par la vinasse. D’autre part, la cendre de charbon à 100 T/ha était définitivement néfaste à la canne à sucre comme indiqué par le rendement en canne plus faible (moyenne de 67.5 T/ha annuellement pour les quatre sites). A 50 T/ha, l’effet de la cendre de charbon sur le rendement dépendait du type de sol, étant plus affecté dans les sols lessivés comme à Belle Rive que dans les sols moins lessivés de la zone sous humide comme à Pamplemousses. En raison de leur faible teneur en métaux lourds, la vinasse aussi bien que la cendre de charbon n’ont pas d’effet sur la concentration des métaux lourds présents dans la canne à sucre. Pour connaître l’effet de l’épandage de 100 m3/ha de vinasse et de 100 T/ha de cendre de bagasse sur la qualité des eaux souterraines, l’eau percolant après chaque grosse pluie à un mètre de profondeur sous des lysimètres établis sur deux sites avec une pluviométrie différente (1500 mm/an à Réduit et plus de 3500 mm/an à Belle Rive) avait été recueillie et analysée durant la période 2005 à 2008. Les résultats ont montré que la vinasse à 100 m3/ha n’accentuait pas les pertes d’azote sous forme de nitrate. Les métaux lourds les plus mobiles en l’occurrence le cuivre, le zinc et le nickel ont également été retrouvés dans les percolâts mais leurs teneurs restaient bien en dessous des seuils recommandés pour l’eau potable préconisé par l’Organisation Mondiale de la Santé , c'est-à-dire, 1mg Cu/L, 5mg Zn/L et 0.02 mg Ni/L. Les résultats de quenching de fluorescence de la matière organique dissoute de la vinasse et de ses fractions (issues de la dialyse) avec le cuivre ont confirmé une bonne complexation entre cette matière organique dissoute et le cuivre. La cendre de bagasse n’avait pas engendré une présence plus prononcée des métaux lourds et des micropolluants organiques dans les eaux drainant à un mètre de profondeur des lysimètres. La seule différence remarquée entre la vinasse et la cendre de bagasse, était une capacité accrue de cette dernière à mobiliser le nitrate dans le sol. Ainsi suite à l’apport de 100 T/ha de cendre de bagasse, la concentration du nitrate dans les percolâts avait durant la période de novembre 2005 à février 2008 dépassé en de nombreuses occasions à Belle Rive et Réduit respectivement, le seuil de 10 mg N-NO3- /L recommandé pour l’eau potable par l’Organisation Mondiale de la Santé. En conclusion, cette étude a donné des résultats forts intéressants et valables qui indiquent que si l’épandage des fortes doses de vinasse peut être accepté, celle de la cendre de charbon est à éviter puisqu’elle n’est pas sans conséquence nuisible pour les sols ou les cultures et même les eaux souterraines. En effet, les fortes doses de cendre de charbon dans les champs de canne à l’île Maurice, conduiraient à une baisse de production et à une pollution plus accentuée de la nappe souterraine par le nitrate / Of the 85 000 hectares of arable land in Mauritius, sugar cane occupies some 85% of that area, the remainder is made up mostly of vegetables and fruit trees. To ensure its economic viability and long term sustanainability, the sugar cane industry through a reform program is striving to add value to its by-products by producing ethanol from molasses and by optimizing energy production from bagasse during the harvest season. However these two avenues generate considerable wastes (400 000 T/yr of vinasse during ethanol distillation and 40 000 T/yr of coal/bagasse ash during the production of electricity), which have to be judiciously disposed of with a minimum of risk to the environment. Among the disposal means for these wastes, the application of vinasse and coal/bagasse ash to agricultural land is believed to represent the most sensible economic option from both the agronomic and environmental point of view. In this context before recommending elimination of the wastes through disposal on agricultural lands, a study has been conducted to determine the effects of high doses of vinasse and coal/bagasse ash on soil quality, on the sugar cane plant and on groundwater quality. Analyses of vinasse samples collected at regular intervals of three months during 2005 to 2008 showed that its chemical composition was very variable. However these analyses also showed that as vinasse contained on average 9.37 g/L of K, its fertilization value was mostly as a source of potassium. Nevertheless at an application rate of 100 m3/ha vinasse, it can in addition represent a significant source of N (average of 122 kg N/ha) and of organic matter (average of 8-15 % dry matter). Vinasse also contained heavy metals (Cu, Zn, Ni, Mn, Pb) but their concentrations were negligible and were well below the detection limit of the atomic absorption spectrophotometer (5 mg/kg for Cu, Zn, Ni, Pb and 10mg/kg for Mn). As opposed to vinasse which is acidic in nature (an average pH of 4.5), coal or bagasse ash is alkaline with a pH varying between 7.5 and 11.5 and can therefore be used to amend soil acidity. When applied at 100 T/ha coal ash would represent a significant source of potassium (average of 139 kg K/ha) and of phosphorus (average of 298 kg P/ha) to the sugar cane crop. Due to its low contents of heavy metals (Cu, Zn, Ni, Mn, Pb, and Hg) and to the absence of organic micro pollutants, coal ash is unlikely to enhance the levels of these contaminants in the soil, in the sugar cane crop or in the groundwater. Laboratory studies had demonstrated that coal and bagasse ash were able to strongly adsorb the herbicides atrazine and hexazinone with a sorption coefficient (km) of 0.13 for atrazine and 0.32 for hexazinone. They would thereby act to decrease the movement of these herbicides to groundwater. Analyses of the soils at the study sites showed that the application of vinasse lowered soil pH from an average of 5.9 to 5.4, but this decrease was only temporary and was not significant enough to affect sugar cane growth. In fact the soil pH returned to its initial value shortly after the application of the 100 m3/ha vinasse. On the other hand, coal ash raised soil pH but this rise in pH was likewise not significant to crop growth. Vinasse and coal ash applied at the high rates of 100 m3/ha and 100 T/ha respectively raised the electrical conductivity of the soil, but in spite of this increase, the electrical conductivity remained below the threshold value of 1700 RS/cm recommended for sugar cane. Furthermore if an application rate of 100 m3/ha of vinasse did increase the organic carbon content of certain soils, it was not observed with coal ash at 100 T/ha. Both vinasse and coal ash improved the level of exchangeable calcium and magnesium in the soils. Thus, 12 months after its application at 100 T/ha coal ash raised the level of exchangeable calcium from 3.40 to 6.61 cmol+/kg in the soil at Pamplemousses, whereas during that same period with vinasse at 100 m3/ha, the level of exchangeable calcium rose only from 1.66 to 1.83 cmol+/kg at Union Park, despite the high K content of the vinasse. Field trials laid down in four different agroclimatic zones provided evidence that increasing application rates of vinasse (25, 50 and 100 m3/ha) did not affect cane or sugar yield. On the contrary, results obtained during the three year study period which covered a plant cane crop and two ratoons, had shown that vinasse gave a higher cane yield (an average of 84.9 T/ha/yr for the four sites) than NPK fertilizers alone (an average of 77.3 T/ha/yr for the four sites). As all the treatment plots received the same rate of N and P, this increase in cane yield was in all probability due to a better K nutrition as well as to an improvement in soil organic matter status brought about by the vinasse. On the other hand, coal ash at 100 T/ha definitely impaired cane yield (an average of 67.5 T/ha/yr for the four sites). When it was applied at 50 T/ha, the effect of coal ash on yield was dependent on soil type, being more severe in the highly leached soils of the super humid region at Belle Rive, and less damaging in the soils having undergone less leaching in the humid region of Pamplemousses. Additionally because of their low heavy metal concentrations, vinasse as well as coal ash did not increase the heavy metal contents in the sugar cane plant. To determine the effects of spreading 100 m3/ha of vinasse and 100 T/ha of bagasse ash on groundwater quality, lysimeter studies were conducted at two sites differing in rainfall regimes (3500 mm/yr at Belle Rive and 1500 mm/yr at Réduit). Drainage water percolating at one metre depth was collected after each heavy rainfall event. Analyses of the leachates showed that the vinasse at 100 m3/ha did not enhance loss of N in the form of nitrate. If, as expected, the heavy metals (Cu, Ni and Zn) known to be mobile had been detected in drainage water, their concentrations remained well below the drinking water limits proposed by the World Health Organization (1 mg/L for Cu, 5 mg/L for Zn and 0.02 mg/L for Ni). Fluorescence quenching studies of the dissolved organic matter in vinasse and of its dialysis fractions with copper confirmed the formation of complexes of the dissolved organic matter with copper. As expected, bagasse ash did not increase the levels of heavy metals and organic micropollutants in the drainage water. But bagasse ash as opposed to vinasse moved significantly more nitrate into the groundwater. In fact the limit of 10 mg/L N-NO3- recommended by World Health Organization for drinking water, was exceeded on many occasions during the study period of November 2005 to February 2008 at both Belle Rive and Réduit lysimeters. To conclude, this study has provided some pertinent and very valuable data. Whereas the disposal of high rates of vinasse on agricultural land under sugar cane is acceptable, the same cannot be stated for coal ash which must be avoided as it is would represent a hazard to the sugar cane crop and to groundwater. Indeed, high application rates of coal ash to sugar cane fields in Mauritius will eventually lead to a decrease in sugar cane productivity and to an increase in nitrate contamination of groundwater
23

O perfil do desenvolvimento socioeconômico dos municípios paranaenses que possuem agroindústria canavieira: estudo de caso / The profile of the socioeconomic development of the municipal districts that have cane agro-industry: case studies. 2010

Deliberali, Edson Antonio 06 August 2010 (has links)
Made available in DSpace on 2017-07-10T18:33:47Z (GMT). No. of bitstreams: 1 Edson Antonio Deliberali.pdf: 966799 bytes, checksum: afc55b6e35c1c774a3ee93a88e66c098 (MD5) Previous issue date: 2010-08-06 / This study has the objective of expose the profile of socioeconomic development of municipalities of Paraná that have sugar-cane Agro-Industry (in this figure as the main force). First of all was used the analysis method of principal components to create socioeconomic development Indicator (IDSE) to Paraná cities. After that is elected a city with a low (IDSE) and another with a high one to be done a individual case study. In case of low IDSE the search showed a lack of joint actions between the community and the local unit producing to improve population life. The only relationship directly in this case evidenced by generation jobs provided by the plant versus income (salary) paid to its collaborators. The plant uses to hire workers with permanent housing in the city or region. The mechanization of cane cutting and adult sand young people illiteracy is a short-term concern for the local population. In case of high IDSE the relation between local agro-industry and the city is more intense. The unit participates with social activities, and promotes indoors activities at the company to improve some indicators. The city has bigger opportunities of job vacancies, but also tends in a near future encounter with implementation of the mechanization of its sugar cane plantation. The hand-manpower available for the plant consists of three profiles worker, the former worker and resident in municipality most often occupies other positions that do not cutting sugar cane, and frequent training courses during the off-season, the second worker the region, and the third wheel is the worker, other regions of the country coming to town and settles provisionally (during harvest) the end of the harvest they return to their homeland bringing with economies who managed to save. That way that way for this two cases in particular, that the sugar industry influence the local economy of the town which is located, because it directly promotes employment and income, which provides access to consumer goods, health, education and others, and indirectly through actions Community influences the improvement of Socioeconomic municipalities indicators where they are located. / Esse estudo tem como objetivo expor o perfil do desenvolvimento socioeconômico dos municípios paranaenses que possuem agroindústria canavieira (em que esta figura como força motriz). Primeiramente, utilizou-se o método da Análise dos Componentes Principais para criar um Indicador de Desenvolvimento Socioeconômico (IDSE) para as cidades paranaenses. Na sequência, elegeu-se uma cidade com baixo IDSE e outra com alto IDSE para ser realizado estudo de caso individual. Para o caso de baixo IDSE, os resultados pesquisa apresentou a falta de ações conjuntas entre a comunidade e a unidade produtora local em prol da melhoria das condições de vida da população. A única relação diretamente evidenciada nesse caso é através da geração de empregos proporcionada pela usina versus a renda (salários) paga aos seus colaboradores. A usina contrata trabalhadores com moradia fixa na cidade e na região. A mecanização do corte da cana e o analfabetismo de jovens e adultos é uma preocupação de curto prazo para a população local. Para o caso do município de alto IDSE, a relação evidenciada entre a agroindústria local e o município é mais intensa, a unidade agroindustrial local participa com ações sociais, bem como promove atividades internas na empresa para a melhoria de alguns indicadores. O município conta com uma maior diversidade de oportunidades de vagas de emprego, mas também tende, no futuro próximo, a deparar-se com implementação da mecanização em seus canaviais. A mão de obra disponível para a usina é composta por três perfis de trabalhador: o primeiro, trabalhador e morador no município, na maioria das vezes ocupa outros cargos que não no corte de cana, é frequentador de cursos de qualificação durante o período de entressafra; o segundo, o trabalhador da região; e o terceiro é o trabalhador volante, de outras regiões do país, que vem para o município e se estabelece provisoriamente (durante a safra), indo embora, ao término da safra, para a sua terra natal, levando consigo as economias que conseguiu economizar. Assim, pôde-se validar, para esse dois casos em específico, que a agroindústria canavieira local influencia a economia do município onde está localizada, isto porque, diretamente, promove emprego e renda e isso proporciona acesso a bens de consumo, saúde, educação e outros, e, indiretamente, através de ações comunitárias que influenciam a melhoria de indicadores socioeconômicos dos municípios onde estão localizadas.

Page generated in 0.0628 seconds