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1
Faust, Robert Edward. "Lead belt progressives : the struggle for social and environmental reform in Missouri mining communities /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p3115543.
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Cornelissen, Tatiana. "Herbivory by leaf-miners on Florida scrub oaks." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001486.
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Perry, Stuart John. "Community dynamics of leaf-miners annd their parasitoids on Alder." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321761.
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Cheah, Carole A. S. J. "Biological control of the chrysanthemum leaf-miner." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254067.
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Krizanich, Gary W. "An investigation of lead and other metal contaminants in the sediments of Clearwater Lake, Missouri." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.mst.edu/thesis/pdf/krizanich_dis_09007dcc80601ec2.pdf.
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Thesis (Ph. D.)--University of Missouri--Rolla, 2007.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed July 31, 2008) Includes bibliographical references (p. 185-197).
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Beak, Douglas Gerald. "Lead and arsenic speciation and bioaccessibility following sorption on oxide mineral surfaces." Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1131933545.
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Cotter-Howells, Jane. "Lead minerals in soils contaminated by mine-waste : implications for human health." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/8913.
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Vazquez-Ortega, Angelica. "Mobilization of Lead and Zinc in Acid Sulfate Mine Tailings." Thesis, The University of Arizona, 2008. http://hdl.handle.net/10150/193339.
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In this thesis, column experiments were conducted in order to determine the effect of irrigation with local groundwater on mobilization of lead and zinc in 50 years old sulfate-acid mine tailings. In addition, the influence of soluble oxalic acid, a common rhizosphere organic acid, was assessed by varying its concentration across an environmentally relevant range. In general, metal contaminant dissolution was not affected by the presence of oxalic acid. In both tailings, Zn mobilization was higher than Pb suggesting the presence of more kinetically labile Zn phases, regardless of the treatment used. Lead mobilization was also low because effluent solutions were near to equilibrium conditions with respect to gypsum, preventing Pb dissolution from Pb-sulfate minerals. Geochemical modeling also indicated that lead release was controlled by anglesite and plumbojarosite dissolution. Zinc release appears to be controlled by Zn-talc and goslarite.
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Ben, Husin Taha Omar Ali. "Biological control of tomato leaf miner Tuta absoluta using entomopathogenic nematodes." Thesis, University of Newcastle upon Tyne, 2017. http://hdl.handle.net/10443/3845.
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Increasing resistance to chemical insecticides in field populations of tomato leafminer, Tuta absoluta, has motivated research on alternative control measures. Biological control with entomopathogenic nematodes (EPNs) can be an alternative, particularly against larval instars. In foliar application, EPNs encounter many factors that affect their survival and efficacy adversely. This thesis has investigated: (1) the efficacy of some commercial EPNs against different stages of Tuta absoluta (larvae, pupae and adults) in Petri dish, leaf and soil bioassays, (2) factors affecting EPNs on tomato leaves and (3) impact of some organic and non-organic adjuvants on efficacy of EPNs at 75 ± 10 % and 45 ± 10 % RH. Results showed high adult and larval mortality of Tuta absoluta using Steinernema feltiae, Steinernema carpocapsae and Heterorhabditis bacteriophora in dish and leaf bioassays in optimum conditions (> 90 % RH). S. feltiae was the most virulent species, followed by S. carpocapsae then H. bacteriophora. Larval susceptibility increased throughout larval development. Pupae in contrast were less susceptible to nematode infection. In soil, S. feltiae and S. carpocapsae were significantly more virulent than H. bacteriophora against fourth larval instar when they drop to pupate in the soil and against adults when they are emerging from pupae. All factors studied (relative humidity, temperature, repeat application, method of application and time for EPNs to enter a leaf) affected the efficacy of EPNs to some extent, but relative humidity (RH) was the most important factor. EPNs’ efficacy and survival decreased as RH declined. The addition of Barricade® II and xanthan gum to aqueous suspensions of S. feltiae and S. carpocapsae resulted in increasing their efficacy and survival. What is more, they reduced the loss of nematodes into the soil in run-off by depositing them on the leaf and they assured even distribution of nematodes in the spray tank by preventing them from settling down. Moreover, Barricade® II (1.5 %) reduced the time required by S. feltiae and S. carpocapsae to enter a leaf. Barricade® II is the candidate adjuvant to be used with S. feltiae for foliar application against T. absoluta.
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MOREIRA, SANDRA R. D. "Determinacao de sup210Pb em aguas minerais da cidade de Aguas da Prata." reponame:Repositório Institucional do IPEN, 1993. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10348.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Rosvall, Gustav, and John Palmborg. "Hur kan lean production implementeras i ett mindre företag?" Thesis, KTH, Industriell produktion, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-192675.
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Denna rapport behandlar en filosofi kallad Lean production som handlar om hur ett företag kan optimera sin produktion för högre effektivitet och lönsamhet. Tankesättet kommer ursprungligen från en av världens största biltillverkare Toyota, och har efter framgångarna det medförde hos dem blivit känt inom industrin och används idag runt om i hela världen.Syftet med rapporten är att besvara frågeställningen om hur Lean production kan implementeras i ett mindre globalt företag. En litteraturstudie är gjord om ämnet Lean production och dess filosofi samt mer specifikt området Lean production inom mindre företag. Med litteraturstudien som grund har en fallstudie gjorts på ett mindre globalt tillverkande företag där målet var att ge förslag på hur Lean production effektivt kan implementeras i företaget. Orsaken till att företaget skulle behöva implementera Lean är att det innehar stora säkerhetslager på den fabrik där produktionen sker, och som binder stora mängder kapital och även mycket slöseri i form av bland annat svinn. Det mindre producerande globala företaget refereras till som "Octa AB" i denna rapport. Octa AB ägdes tidigare av ett betydligt större företag, och genomförde under dess styre en satsning för att implementera Lean. Denna satsning anses generellt blivit ett misslyckande och har därför använts som grund vid arbetet att föreslå hur en implementering ska genomföras med lyckat resultat. Idag pågår ingen satsning för att bli Lean på företaget.De mest utmärkande resultat som framkommit under arbetet och som besvarar frågeställningen är:- Företagets ledning måste agera som den tydliga ledaren och engagerat driva satsningen. Ledningen måste också förstå fabrikens specifika behov. Tar ledningen inte implementeringen seriöst kommer inte heller resten av företaget göra det.- Tillsätta en person som enbart jobbar med Lean på uppdrag från ledningen.- Inte göra alla ändringar på en gång, börja med små metoder som är lättare att implementera för att undvika för snabba och stora förändringar i arbetssättet.- Anpassa implementeringen efter att det är ett mindre företag. Alla metoder som fungerar bra för ett stort företag kanske inte gör det för ett mindre.This report deals with a philosophy called Lean production which is about how a company can optimize its production to achieve a higher efficiency and profitability. The thinking is originally from one of the world's largest automaker Toyota, and after the success it brought with them they become world-known in the industrial world and the method is used around the world.The report aims to answer the question of how Lean production can be implemented in a smaller global company. A literature study is made on the topic Lean production and its philosophy, and more specifically the area of lean production in smaller companies. With literature study as foundation a case study has been done on a smaller global manufacturing companies where the goal was to provide suggestions on how Lean production can be effectively implemented in the company.The reason that the company would need to implement Lean is that it holds large safety stocks at the factory where production takes place, and which binds large amounts of capital and are also very wasteful. The smaller producing global company is referred to as "Octa AB" in this report.Octa AB was previously owned by a much larger company, and conducted under its rule an effort to implement Lean. This effort is generally considered to have been a failure and has therefore been used as the basis for the work that suggest how an implementation will be carried out successfully. There is no effort to be lean in the company today. The most distinctive results that emerged during the work and that answers the question is: - The company's management must act as the clear leader and committed operate the venture. Management must also understand the plant's specific needs. If the management is not taking the implementing seriously nor will the rest of the company to do it. - Appoint a person who only jobs participation is implementing Lean on behalf of management. - Do not make all the changes at once, start with small methods that are easier to implement in order to avoid too rapid and major changes in operation. - Customize implementation after the fact that it is a smaller company. Any method that works well for a large company may not do it for smaller once.
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Steinberg, José Gustavo. "Lean Mining: modelagem e melhorias em cadeias logísticas minerais." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3134/tde-17052011-114921/.
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Os processos extrativos tradicionais apresentam estágios que precisam de modernização e melhorias para permitir que as empresas mineradoras provisionem de maneira eficaz a qualidade e a quantidade de seus produtos. Tal garantia de provisão, tão difícil de sustentar devido à natureza intrínseca da incerteza geológica, pode somente ser conseguida com um aumento de eficiência nas cadeias logísticas minerais. Este trabalho demonstra os benefícios de se criar modelos de cadeias logísticas minerais existentes para identificar e compreender os pontos de criação de valor para possíveis intervenções visando melhorias. O trabalho também fornece um guia de modelagem, através de uma planilha eletrônica, permitindo aos usuários modelar quaisquer tipos de cadeias logísticas. O conhecimento do trajeto dos processos desde a extração ao consumidor final fornece uma oportunidade única para que os gerentes melhorem suas cadeias logísticas. Depois que o modelo foi criado, ele pode e deve ser melhorado. Um número técnicas e boas práticas já em uso por outros setores, mas ainda não aplicado setor mineiro são identificadas e estruturadas. Uma metodologia para a aplicação estratégica destas técnicas é então fornecida. O setor mineiro em todo mundo está sob pressão para procurar métodos para melhorar sua eficiência. Este trabalho introduz, de uma maneira inovadora, uma estratégia administrativa na mineração que se provou extremamente competitiva em outras indústrias. A questão básica abordada neste trabalho é como desenvolver uma metodologia robusta e controlada para que o setor mineiro tire proveito da filosofia enxuta, introduzindo o conceito de Lean Mining.Traditional extractive processes present stages that need modernization and optimization for enabling mining companies to warrant the effective achievement of both product quality and quantity. Such warranty, which is difficult to sustain due to the intrinsic nature of geological uncertainty, can only be achieved through an increased efficiency in the mineral supply chain. This work demonstrates the benefits of creating models of existing mineral supply chains to identify and understand the points of value creation and places for possible improvement interventions. It also gives a modeling guide, through an electronic chart, enabling users to model any kind of supply chain. The knowledge of the process path from extraction to final consumer provides a unique opportunity for managers to improve the mineral supply chain. After the model has been created, it should and must be improved. A number of techniques and good practices already in use by other sectors but not yet applied to the mining industry are identified and structured. A methodology to strategical application of these techniques in provided. The mining industry all over the world is under pressure to look for methods to improve its efficiency. This work leads the way to an innovative managerial strategy in mining that has proved itself extremely competitive in other industries. The key issue addressed in this work is how to identify a robust and risk-controlled path for the mining industry to benefit from the lean thinking approach, introducing the concept of Lean Mining.
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Ccatamayo, Barrios Johnny Henry. "Aplicación de filosofía Lean en la preparación minera, mina El Teniente Codelco Chile." Tesis, Universidad de Chile, 2017. http://repositorio.uchile.cl/handle/2250/147376.
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Magíster en MineríaLa División el Teniente a cargo de la Gerencia de Obras Mina (GOBM), pasa por un proceso de reformulación de la preparación minera, cuyo objetivo principal es aumentar la productividad y la eficiencia en la ejecución de desarrollos horizontales. Dentro del problema identificado se encuentra; los bajos tiempos productivos en postura, producto de esta deficiencia se tiene que hoy en día el tiempo productivo de trabajo por turno en postura es 4,94 hrs (Green ingeniería, 2014). Esta investigación se enmarca particularmente en la Mina Esmeralda. Para esto se analizaran los procesos de excavación horizontal (Ciclo de minado) y sus variables asociadas mediante la Filosofía LEAN, con la herramienta Mapeo de Cadena de Valor (MCV). La aplicación de esta herramienta permite representar la secuencia de actividades en un mapa de flujo, se divide en 4 etapas. La primera etapa desarrolla las adaptaciones al MCV definiendo como y que datos se recopilan en terreno y los cálculos que se realizarán. En la segunda etapa se realiza el Mapeo del Estado Actual donde se recopilan los datos en terreno del ciclo de minado en una frente y multifrentes, los resultados establecen que el tiempo del ciclo total de las excavaciones horizontales es de 22,1 hrs. En la tercera etapa se desarrolla el Mapeo del Estado Futuro donde se realiza el diagnóstico y posibles causas de las actividades identificadas como de menor rendimiento. En la cuarta etapa se realiza la implementación del Estado Futuro, donde se propone el plan de optimización de las actividades de menor rendimiento, se propone cambiar el explosivo AnFo por Emulsión bombeable. Esto significa reducir la sobre excavación hasta 18%, mayor eficiencia de avance hasta el 95% y reducir el tiempo de emisión de gases pos tronadura hasta 20 min. La aplicación del MCV en terreno fue práctica y se comprueba que eligiendo indicadores adecuados a medir, la herramienta permite elaborar un diagnóstico certero y acabado del estado de producción actual. Las mejoras propuestas y sus recomendaciones de implementación se basaron principalmente en las filosofías Lean Manufacturing , esta constituye estados de producción factibles y de gran optimización para la productividad.
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Goutier, Françoise Mélanie. "Galena lead isotope study of mineral deposits in the Eagle Bay Formation, southeastern British Columbia." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26264.
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The Eagle Bay Formation in the Adams Plateau-Clearwater area, 35km northeast of Kamloops, hosts several economic and sub-economic mineralized occurrences. The age and genesis of these mineral deposits can be estimated by using a specific growth curve which depicts the lead evolution for the Eagle Bay Formation. This curve, named the remodeled curve, represents a local deviation from the average 'shale' curve of Godwin and Sinclair (1982) for the autochthonous part of the Canadian Cordillera. This remodeled curve is specifically applicable to the Adams Plateau-Clearwater area. The lead isotope data from the deposits of the Eagle Bay Formation plot in three distinct clusters along the curve indicating that the lead isotopic signature of the Eagle Bay Formation is upper crustal, and that three periods of mineralization can be recognized or 'fingerprinted'. Accordingly, mineralization cogenetic with Devonian volcanism, and veins related to Cretaceous magmatism can be distinguished by location of galena-lead isotope values within clusters 1 or 3 respectively. Cluster 2 reflects a Late Triassic pulse of mineralization and includes epigenetic veins and stratiform deposits. These deposits are either replacement or cogenetic with their host. The Triassic model age for mineralization that is apparently stratiform and cogenetic raises questions about the currently assigned Cambrian age of associated host rock. To accommodate the lead isotope data a new Upper Triassic unit (T-EBG) within the Eagle Bay Formation is defined.
The distinctive lead isotopic signature between deposits hosted by the Eagle Bay Formation is valuable as a guide for future mineral exploration programs in the Adams Plateau-Clearwater area. Recognition of lead isotopic fields that fingerprint types of mineral deposits, provides a useful and practical framework for the classification and evaluation of new mineralized prospects in the area.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
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Childe, Fiona. "Uranium-lead geochronology of metamorphic accessory minerals south of the Grenville Front, western Québec, Canada." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61060.
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U-Pb ages were determined on single grains of monazite and xenotime as well as small populations of rutile from amphibolite to granulite facies metasediments of the Quebec Gneiss Segment of the Grenville Province in an area extending 45 to 135 km south of the Grenville Front in La Verendrye Park, Quebec. Recent geochronological studies include Pb-isotope ratios of metamorphic minerals corresponding to ages of 2.5 to 2.65 Ga and U-Pb monazite ages to 2649 to 2655 Ma, which define a lower discordia intercept of approximately 1.01 Ga. Recent thermobarometric studies indicate the presence of two metamorphic episodes in the region.Monazite and xenotime grains obtained from high grade metasediments at five locations between 45 and 70 km southeast of the Grenville Front yielded $ sp{207}$Pb/$ sp{206}$Pb ages of 999 $ pm$ 5 Ma to 1021 $ pm$ 2 Ma. Monazite from the norther part of this terrane also defined an upper intercept age of 2596 $ pm$ 3 Ma.
The southernmost sample location, 135 km south of the Grenville Front, yielded both monazite and rutile. Monazite gave an age of 1072 $ pm$ 2 Ma. Small populations of rutile yielded an age of 916 $ pm$ 2 Ma. (Abstract shortened by UMI.)
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Maunsell, Sarah. "Food Webs along Elevational Gradients: Interactions among Leaf Miners, Host Plants and Parasitoids in Australian Subtropical Rainforest." Thesis, Griffith University, 2014. http://hdl.handle.net/10072/368145.
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Gradients in elevation are used to understand how species respond to changes in local climatic conditions and are therefore a powerful tool for predicting how mountain ecosystems may respond to climate change. While many studies have shown elevational patterns in species richness and species turnover, little is known about how multi-species interactions respond to elevation. An understanding of how species interactions are affected by current clines in climate is imperative if we are to make predictions about how ecosystem function and stability will be affected by climate change.
This challenge has been addressed here by focussing on a set of intimately interacting species: leaf-mining insects, their host plants and their parasitoid predators. Herbivorous insects, including leaf miners, and their host plants and parasitoids interact in diverse and complex ways, but relatively little is known about how the nature and strengths of these interactions change along climatic gradients. In order to determine how elevational changes in climatic conditions affect interactions among leaf miners, their host plants and their parasitoids, I quantified these communities and their interactions along three elevational gradients in eastern Australian subtropical rainforest. In doing so, I aimed to 1) provide information on host plant use of leaf miners and the elevational associations of these relationships, 2) understand how the species richness and assemblage composition leaf miners and their parasitoids, and composition of interactions with their hosts (plants or leaf miners), is affected by elevation, 3) uncover any elevational changes in the structure of quantitative networks connecting leaf miners and their parasitoids, and 4) test if parasitism pressure increases at the lower edge of, and below the elevational range of a specific leaf miner species.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
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Mussi, Toschi Vitoria. "Lead-free ferroelectric ceramics for multilayer ceramic capacitors." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC089.
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De nos jours, la consommation des condensateurs céramiques multicouches (MLCCs) augmente en raison de leur efficacité et leur fiabilité. La miniaturisation résultant dans une plus grande dissipation volumique de chaleur et les nouvelles applications demandent des MLCCs qui peuvent travailler de 300 à 350°C, au-delà des limites actuelles de 200 – 250°C. De plus, les exigences environnementales augmentent également avec les réglementations REACH et RoHS qui interdisent l'utilisation du plomb en Europe. Il est donc impératif de créer des nouveaux matériaux sans plomb capables de répondre aux nouvelles attentes des MLCC.Cependant, la compatibilité avec les méthodes de production industrielle, ainsi que les prix du marché sont des limites importantes. Trois familles de matériaux sans plomb ont été examinées : celle du BaTiO3 (BT), du K0.5Na0.5NbO3 et du Na0.5Bi0.5TiO3 (NBT). Le NBT-BT à la MPB (6 % BT) a été choisi comme matériau diélectrique de base. Plusieurs méthodes et paramètres de synthèse ont ensuite été étudiés pour déterminer les meilleures conditions de synthèse. La synthèse à l'état solide et le frittage traditionnel ont été choisis pour les échantillons en massif et le coulage en bande a été choisi pour les couches. Pour éviter l'évaporation des espèces volatiles, le frittage a été effectué en couvrant le NBT-BT par une poudre de ZrO2. Tous les échantillons présentaient des phases secondaires contenant du Ba (Ba2TiO4 et Ba2Ti9O20) en raison de l'évaporation du Na pendant le frittage. Un effet de peau créé par la coexistence des phases tétragonale, rhomboédrique et cubique a également été observé, lié à la concentration locale de Ba dans le réseau cristallin du NBT. Les effets des paramètres de synthèse et la stœchiométrie des réactifs sur les propriétés diélectriques, la résistance d'isolement et la séparation des phases ont été analysés. La stœchiométrie nominale Na0.44Bi0.48Ba0.06TiO3 était la plus appropriée pour les MLCC en raison de sa résistance d'isolement élevée, de ses faibles pertes diélectriques et de sa stabilité de la permittivité en température. La présence de phases secondaires est initialement bénéfique en raison de l'élimination des lacunes d'oxygène. Au-delà d'une fraction volumique critique (2.5 à 3.0 %) et d'une taille de grain moyenne critique (0.9 à 3.0 m2), la tendance s'inverse en raison de la nature conductrice des phases secondaires.Pour atteindre la fraction volumique et la taille de grain critiques, un agent dispersant a été utilisé lors du broyage dans la jarre de YSZ, avec du MEK et de l'éthanol comme solvants, et sans sécher les réactifs avant la pesée. Enfin, la relaxation des contraintes a été réalisée à 400°C pendant 3 heures. Trois modèles ont été utilisés pour expliquer la dispersion des propriétés diélectriques en fréquence : le modèle de Maxwell-Wagner, le modèle de Nyquist et la loi de Curie-Weiss modifiée. Les incompatibilités entre les propriétés diélectriques du NBT-BT rapportées dans la littérature ont ensuite été analysées soulignant l'importance d'avoir des méthodes de synthèse et de mesure strictes. Les trois principaux facteurs affectant les propriétés diélectriques induisant ces incompatibilités étaient la stœchiométrie, la méthode de métallisation et la fixation des fils électriques à l'aide de la laque d'argent. Des pertes diélectriques croissantes à haute température a aussi été observée après chaque cycle thermique dépassant les 300°C, indiquant une dégradation thermique des échantillons.Enfin, les monocouches céramiques ont montré une faible densité (62%) après frittage, limitant la plage de température correspondant aux spécifications d'Exxelia. Cependant, en utilisant un pressage des couches avant frittage, l'échantillon multicouche fritté présentait une densité élevée (89%). Une mesure des propriétés diélectriques doit être effectuée sur cet échantillon multicouche synthétisé, afin de déterminer sa compatibilité avec les spécifications d’ExxeliaMLCC consumption is today increasing due to their high efficiency, reliability and frequency characteristics. MLCCs that can work from 300 to 350°C are required both for miniaturization, resulting in greater volume heat dissipation and for new applications. Moreover, environmental requirements are also increasing, the REACH and RoHS regulations prohibiting the use of lead in Europe. It is imperative to create new lead-free materials that are able to meet those requirements.However, the compatibility with the production methods, price, and market are important industrial limitations that need to be considered.Three families of lead-free materials were examined: BaTiO3-based, K0.5Na0.5NbO3-based and Na0.5Bi0.5TiO3-based materials. NBT-BT at the morphotropic phase boundary (6% BT) was chosen as the base dielectric material.Several synthesis methods and parameters were studied to determine the best synthesis conditions. Solid-state synthesis and traditional sintering were chosen for the bulk samples and tape casting was chosen for the layer samples preparation. Sintering was done under ZrO2 powder to prevent the evaporation of volatile species.All samples had secondary Ba-containing phases (Ba2TiO4 and Ba2Ti9O20) formed because of the evaporation of Na during sintering. A skin-effect was observed due to a phase coexistence (tetragonal, rhombohedral, and cubic) due to the local concentration of Ba in the NBT lattice.The effects of the synthesis parameters and the stoichiometry of the reactants on dielectric properties, insulation resistance, and phase separation were analysed.The Na0.44Bi0.48Ba0.06TiO3 nominal stoichiometry was the most suitable for the MLCCs due to its high insulation resistance, low dielectric losses, and stability of permittivity in temperature.The phase separation was initially beneficial, due to the resulting elimination of oxygen vacancies. Above a critical volume fraction (2.5 to 3.0%) and a critical mean surface area (0.9 to 3.0 m2), the trend was reversed due to the conductive nature of the secondary phases.To achieve the critical volume fraction and surface area of the secondary phases, a dispersing agent was used during ball-milling in YSZ jar, with MEK and ethanol as solvents, and without drying the reactants prior to weighing. Finally, a strain relaxation was done at 400°C for 3 hours.Three models explained the frequency dispersion of the dielectric properties: the Maxwell-Wagner model, the Nyquist plot and the modified Curie-Weiss law.Incompatibilities between the dielectric properties of NBT-BT reported in the literature were then analysed, showing the importance of maintaining strict synthesis and measurement methods. The three main factors affected the dielectric properties, creating these incompatibilities in the bulk samples. There were the stoichiometry, the metallization method, and the fixing of the electrical leads using silver paste.An increase of the high-temperature dielectric losses after each thermal cycle reaching more than 300°C was observed, indicating a thermal degradation of the material.Finally, the sintered ceramic monolayers showed a low density (62%), limiting the temperature range corresponding to Exxelia’s specifications. However, after pressing the layers together before sintering, the sintered multilayer sample showed a high density (89%). Dielectric property measurement should be carried out for these synthesized multilayers
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Smith, Peregrine Hugh Duncan. "Population dynamics of the holly leaf miner, 'Phytomyza ilicis' on urban-rural-gradients." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402466.
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NIERI, ARTIDORO. "Determinacao de sup210 Pb e sup210 Po em aguas minerais radioativas." reponame:Repositório Institucional do IPEN, 1996. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10479.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Diaz-Unzueta, Raul 1957. "GEOCHEMICAL AND ISOTOPIC STUDY OF CALCITE STOCKWORKS AT LA ENCANTADA MINING DISTRICT, COAHUILA, MEXICO: RELATIONSHIPS WITH OREBODIES AND IMPLICATIONS FOR EXPLORATION." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276408.
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Salih, Talal Sabhan. "Heavy metal inducible antimicrobial activity of Streptomyces spp. isolated from the Leadhills and Wanlockhead lead mines in Scotland, UK." Thesis, University of Strathclyde, 2017. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=28942.
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There is a real and urgent need for new antimicrobial compounds to combat the rise of multidrug resistant infections. Whole genome sequencing and genome mining have revealed that Streptomyces spp. possess a range of biosynthetic gene clusters for secondary metabolites, however many of them are silent and cryptic under conventional laboratory conditions. It has also been shown that triggering the expression of these cryptic gene clusters in Streptomyces might yield novel antibiotics. Here, we isolated over 100 Streptomyces strains from sediments contaminated with heavy metals from a former industrial site in Scotland, United Kingdom. These strains were assayed for heavy metal dependent antimicrobial activity. We have used a combination of genomics, bioinformatics and transcriptomics to investigate these novel strains, providing a phylogenetic context and molecular evidence towards the discovery of the gene clusters responsible for antibiotic biosynthesis. Our findings highlight the potential of using heavy metals for activation of silent biosynthetic metabolite gene clusters in Streptomyces isolated from extreme environments for natural product discovery. These findings are supported by the fact that these compounds are produced only in the presence of sub-inhibitory concentrations of heavy metals but not in the absence of metal induction. Whole genome sequencing has enabled us to investigate the taxonomy and biosynthetic capacity of the strains whilst transcriptomic analysis and bioinformatics tools are allowing us to investigate the changes in the transcript levels of these genes that occur under metal-inducing conditions.
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Berger, Madeleine. "Investigating the molecular mechanisms of insecticide resistance in the tomato leaf miner Tuta Absoluta." Thesis, University of Nottingham, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.718672.
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Tuta absoluta is an economically significant pest of tomatoes, which has undergone a rapid expansion in its range during the past six years. One of the main means of controlling this pest is through the use of chemical insecticides including pyrethroids and spinosad. However, their intensive use has led to the development of resistance. The aim of this PhD was to understand the mechanisms underlying resistance to pyrethroids and spinosad. The target site of pyrethroids, the sodium channel, was cloned and three known knockdown resistance mutations, L1014F, M918T and T929I were found. High-throughput diagnostic assays were developed and the prevalence of the three mutations was then assessed. All three mutations were found at high frequencies in populations across the range of T. absoluta. Additionally, a fourth novel mutation L925M was found in 14% of samples. Therefore, pyrethroids are unlikely to be effective at controlling T. absoluta. Bioassays were conducted to determine the sensitivity of five populations of T. absoluta to spinosad. One population, from an area where control failure using spinosad was reported in 2012, exhibited a high level of resistance after selection in the laboratory with spinosad. Synergist bioassays did not show enhanced activity/expression of P450s and esterases. The transcriptome of T. absoluta was sequenced and used, in combination with degenerate PCR, to identify the target site of spinosad, the nicotinic acetylcholine receptor (nAChR) a6 subunit. Analysis of Taa6 revealed that two mutually exclusive exons (3a and 3b) that encode loop D of the ligand binding domain are both absent in all transcripts from the selected strain. Additionally, QPCR showed that a6 is down regulated in both larvae and adults of the selected strain. Taken together this study has provided new data on the molecular basis of resistance of T. absoluta to pyrethroids and spinosad.
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Dennis, Russell E. "Aspen leaf miner (Phyllocnistis populiella) oviposition site preference mediated by expression of extrafloral nectaries." Thesis, University of Alaska Fairbanks, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1551924.
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As herbivorous insects choose where to lay their eggs, maximizing larval performance (optimal oviposition) may be at odds with adult foraging (optimal foraging). Aspen leaf miners (Phyllocnistis populiella; ALM) may choose between leaves with or without extrafloral nectaries (EFNs) as oviposition sites on quaking aspen (Populus tremuloides Michx.). Reduced ALM mining on leaves with EFNs may be linked to predators that defend leaves and feed at EFNs, and to increased concentrations of secondary leaf compounds. However, direct responses of adult ALM to EFN expression may also explain differences in ALM mining among leaves with and without EFNs. ALM might be less likely to oviposit on leaves with EFNs because these leaves provide poor conditions for larval development. With choice experiments and surveys of ALM oviposition, we examined oviposition site preference in relation to EFN expression. In choice experiments and field surveys adults preferred to oviposit on leaves without EFNs. Increased oviposition was also observed on shoots with high EFN frequencies, suggesting a combination of optimal foraging and optimal oviposition, and a role of EFNs at scales above the leaf level. Higher predation on leaves with EFNs likely exerts selective pressure for the observed ALM oviposition preference for non-EFN leaves.
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Nekvapil, Viktor. "Data Mining in Customer Relationship Management: The Case of a Major Logistic Company." Master's thesis, Vysoká škola ekonomická v Praze, 2012. http://www.nusl.cz/ntk/nusl-124538.
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The thesis addresses possibilities of deploying the open source data mining system LISp-Miner in the customer relationship management (CRM), specifically in the area of lead management. This is basically a process of finding information about potential customers, qualifying those customers according to their potential (future value), and turning the selected potential customers to real customers. The data used includes the records concerning the lead management of a major logistic company operating worldwide (the company wanted to stay in anonymity). The data is analysed using the LISp-Miner system which is an academic software developed at the Faculty of Informatics and Statistics at the University of Economics, Prague. The thesis also pays attention to the collaboration with the business experts of the company which provided the data. The principle aim of the thesis is to provide information contributing to the possible change of internal processes of the company. Further aims are to propose directions of the use of the LISp-Miner system when solving a similar data mining task, and propose a simple and understandable way how to present the results. The aims have been achieved by doing the analysis in compliance with the CRISP-DM Methodology. The asset of the thesis is the description of the whole project which includes the analysis of real data using the LISp-Miner system. Further result of the thesis is the description of the lead management domain. Finally, the thesis offers the instructions and recommendations for future similar projects. Section I outlines the LISp-Miner system and its procedures. Section II - A case study describes the process of analysing the data. Two cycles ("iterations") of the analysis were performed. The chapters devoted to the both iterations have been structured according to the phases of the CRISP-DM Methodology. Section III summarises the observations gained during the entire project. Moreover, it gives recommendations and instructions for the application in case a similar project of the data analysis using the LISp-Miner system is designed.
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Stenberg, Sandra. "Förstudie med förändringsförslag för omorganisation av mindre företag." Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-2873.
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BAGA Water Technology är ett svenskt företag som är verksamt inom vattenhantering med fokus på konstruktion och tillverkning av reningsverk särskilt anpassade för att klara de nordiska förhållandena. De är en av marknadens ledande aktörer inom området vilket gör att en ständig utveckling krävs för att konkurrenskraften ska bibehållas. Företagets huvudkontor är beläget i Karlskrona medan produktion och lagerhållning till största delen är outsourcat till en underleverantör i Norge och en i Blekinge (UL.B). Outsourcingen till UL.B har visat sig inge problem då kvalitén av produkter inte är tillfredsställande samtidigt som den spridda lagerhållningen och produktionen gör logistiksystemet komplext och svårhanterligt. Arbetets syfte är således att göra en förstudie där BAGA erhåller data som kan användas för att ta beslut om en omorganisation av företagets outsourcade lager och produktion är en rimlig lösning på problemen samtidigt som implementerbara förändringsförslag tillhandahålls. Genom användning av Lean Six Sigmas modell för förbättringsarbete, DMAIC, samt förespråkade verktyg har först en nulägesanalys av processer och flöden kopplade till UL.B genomförts. Intervjuer och observationer både på BAGA och hos UL.B har verkat som grundläggande data. Utifrån den samlade informationen har en orsak-verkan analys gjorts med fokus på de båda problemområdena, där orsakerna sedan har prioriterats i en FMEA. Framtagning av tre förbättringsförslag har därefter gjorts, där det förslag som ansågs mest fördelaktigt är att BAGA bör investera i en utökad egen verksamhet genom tillbyggnad av en lagerbyggnad intill kontoret i Karlskrona. Detta möjliggör en förflyttning av lager och produktion från UL.B till BAGA. Beskrivningen av förändringsförslaget presenterar bland annat förändringar i processer och flöden men även förslag på en fysisk utformning där ett effektivitetstänk enligt Lean Six Sigma ständig genomsyrar arbetet. Slutligen presenteras en kostnadskalkyl som jämför nuläget med det föreslagna scenariot där det visar sig att förslaget ger en ekonomisk vinning. Utifrån de många positiva argument som har framkommit, bland annat att förslaget bidrar med minskade transporter och ett ökat inflytande över produktionen, anses det som ett strategiskt riktigt beslut att implementera förbättringsförslaget.
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Campos, García Héctor A., and Paredes Doris Valdez. "Cinco temas controversiales en Materia Tributaria Minera. Entrevista a la Doctora Luz María Pedraza Mac Lean." Derecho & Sociedad, 2017. http://repositorio.pucp.edu.pe/index/handle/123456789/118970.
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Hussein, Ahmed A. (Ahmed Ali) Carleton University Dissertation Earth Sciences. "Application of lead isotopes to mineral exploration using glacial till of the Halfmile Lake Area, Bathurst, New Brunswick." Ottawa, 1996.
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BABINSKI, MARLY. "Metodologia isotopica Pb/Pb. Aplicacao aos migmatitos e rochas." reponame:Repositório Institucional do IPEN, 1988. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9894.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Geoffroy, Gómez Roberto Patricio. "Propuesta para el mejoramiento del proceso de reclutamiento y selección de una empresa minera." Tesis, Universidad de Chile, 2016. http://repositorio.uchile.cl/handle/2250/139103.
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Ingeniero Civil IndustrialLa Vicepresidencia de Proyectos de Codelco es la organización encargada de diseñar, construir y poner en marcha todos los proyectos estructurales de la compañía. Ésta cuenta con Gerencias Funcionales que desempeñan tareas fundamentales para que las Gerencias de Proyectos, representantes de la VP en cada proyecto, puedan llevar a cabo sus labores sin mayores complicaciones. Una de las funciones más importantes es desempeñada por la Gerencia de Recursos Humanos, que se preocupa de la provisión de los profesionales necesarios con el avance de los proyectos. En la actualidad, el área Reclutamiento y Selección presenta retraso en términos de la dotación necesaria para los distintos proyectos debido a los largos tiempos de espera en el proceso; es por esto que el objetivo general de la memoria es proponer un rediseño del proceso que permita aumentar la efectividad y acortar los plazos en la contratación de los profesionales requeridos. Para cumplir esto se utiliza la Metodología LEAN, la cual se define como un sistema cuyo propósito recae en identificar y eliminar desechos de manera continua buscando mejoras operacionales a lo largo de toda la empresa y la cadena de valor . En primer lugar se realiza un diagnóstico de la situación actual del proceso, donde se descubre que tiene una duración promedio de 5,9 meses y que los tiempos de espera corresponden al 83% del total; sin embargo, el cliente del servicio considera que debería tomar como máximo tres. En el análisis de causas del problema de demora se obtiene que los principales desperdicios LEAN están asociados a Tiempos de Espera, Sobreproducción y Procesos Inapropiados, principalmente explicados por la espera de documentos, reelaboraciones y etapas de alta complejidad operacional. Debido a esto, se plantean propuestas de mejora enfocadas en la mayor utilización de la tecnología disponible y la fijación de plazos para ciertas etapas. Con el rediseño se logra disminuir el tiempo total del proceso en un 53,3% lo que implica una duración promedio de 2,73 meses. Además se proponen indicadores que permitan controlar el cumplimiento de estos plazos, conocer la situación respectiva a los profesionales contratados versus lo que fue planificado al principio del año y prestar atención a aquellos procesos que tarden más de tres meses. Como recomendación final se plantea realizar una actualización completa de las bases del procedimiento en el cual se especifiquen todas las etapas, los responsables y una estimación de los tiempos. De este modo se podrá estandarizar el proceso e infundir mayor responsabilidad al cliente en el retraso por incumplimiento de los plazos. Finalmente, se debe insistir en el uso de la Metodología LEAN en la búsqueda continua de mejoras ante problemas que puedan surgir en el proceso.
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Thibodeau, Alyson Marie. "Isotopic Evidence for the Provenance of Turquoise, Mineral Paints, and Metals in the Southwestern United States." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/243111.
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Lead and strontium isotopes are two powerful tracers that can be used to identify or constrain the provenance of a wide range of archaeological materials, but these two isotopic tracers have been rarely employed to infer the sources of artifacts in the southwestern USA. This dissertation contains four studies that demonstrate how these isotopic systems can address questions about the sources of three types of archaeological materials found in this region: turquoise, lead-based glaze-paints, and metals. The analysis of 116 samples of turquoise from 17 deposits in the southwestern USA reveals that lead and strontium isotopes are robust and sensitive tracers of turquoise at multiple scales. Isotopic variation among turquoise deposits correlates with broad regional differences in the geologic and tectonic setting of the rocks and mineral deposits which host turquoise mineralization. Many turquoise deposits also have unique isotopic signatures that will enable insights into ancient patterns of turquoise acquisition at regional and local levels. To show the utility of these tracers when applied to archaeological turquoise, I use lead and strontium isotopic measurements to establish that the Silver Bell Mountains are the likely source turquoise found at the Redtail site in the Tucson Basin, Arizona, USA. This dissertation also contains new, high-precision isotopic ratios of lead ores (galena and cerrusite) from four mining districts in New Mexico, including the Cerrillos Hills. All districts studied are possible sources of lead used by Pueblo IV communities to produce glaze paints. These new measurements, made by multiple-collector ICP-MS, define the isotopic composition of the ore deposits with greater precision and accuracy than achieved in previous studies, indicating an opportunity to improve interpretations about the provenance of lead in glaze paints. Lead isotopes are also found to be useful tools for identifying lead and copper metal associated with the 1540-1542 Vázquez de Coronado expedition. Lead shot and copper crossbow boltheads from two sites with archaeological evidence for the expedition's presence were determined to share similar or identical lead isotopic ratios. I propose this specific isotopic "fingerprint" can be used to identify other artifacts belonging to the expedition in the Southwest.
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Ly, Wing. "Förstudie : Förbättra detaljplanering hos Boliden Mineral AB." Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-19646.
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Boliden Mineral AB (Boliden) är Europas ledande metallföretag med kärnkompetens inom bl.a. gruvdrift och smältverk. Rapporten behandlar frågeställningarna kring detaljplanering (korttid resursplanering) och produktionsprocesser hos Bolidens underjordsgruvor; Garpenberg, Kristineberg, Renström och Tara.Gruvorna brottas med återkommande störningar av olika slag i produktionsledet vilket påverkar måluppfyllelse (planföljsamhet) för de fastställda veckoplanen. Företagets senaste tidstudie i Kristineberg visar att maskinernas utnyttjandegrad inte motsvarar förväntningarna och har en fallande trend. Tidstudien visar även att maskinfel utgör ca 40 % av totala störningarna. Boliden testar olika idéer inom företagets olika funktioner för att finna den optimala (lämpligaste) produktionskonceptet och för att komma till rätta med problemen. Hos Gruvteknik (TG) finns idén att planföljsamhet och maskinutnyttjandegrad kan förbättras genom att automatisera ”korttid resursplanering”.En förstudie genomfördes med målsättning att kartlägga nuvarande verksamhet och fastställa vilka processer som behöver förbättras för att möjliggöra automatisering av ”korttid resursplanering”. Förstudien visar att den låga maskinutnyttjandegraden beror på bristande kännedom om resursernas tillgänglighet, behov, överkapacitet och hög grad av kroniska (små störningar) och sporadiska fel (maskinhaveri) p.g.a. bristande underhåll. Avvikande planföljsamhet beror på bristande planeringsunderlag, bristande kännedom om värdeflöden (produktionskedjan), otillräcklig robust planeringsverktyg, varierande planeringsmetod och otydlig produktionsstrategi. Även de mänskliga faktorerna har en avgörande betydelse för det kaotiska tillståndet.Förstudien resulterar i en åtgärdsplan som kan sammanfattas med fyra nyckeltermer; standardisera, visualisera, effektivisera och rationalisera.Till förbättringsarbete rekommenderas olika leanverktyg och välbeprövade koncept. För automatisering av ”korttid resursplanering” rekommenderas en investering eller utveckling av dataprogram som möjliggör automatiserad loggning av operationsdata för att säkra kvalitet på beslutsunderlag (statistik), och ett stopptidsprogram för att effektivisera maskinernas kapacitet, reducera ställtider och uppnå driftsäker produktion.
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Nilsson, Ulf. "Quantitative in vivo elemental analysis using X-ray fluorescence and scattering techniques applications to cadmium, lead and bone mineral /." Malmö : Dept. of Radiation Physics, Lund University, 1994. http://books.google.com/books?id=hotqAAAAMAAJ.
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Sentsho, Joel. "Export promotion in a small mineral based economy : the case of Botswana." Thesis, University of Strathclyde, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248534.
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Zhang, Wei. "Performance of lead anodes used for zinc electrowinning and their effects on energy consumption and cathode impurities." Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27021/27021.pdf.
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Hayes, Sarah. "Effects of Mineral Weathering and Plant Roots on Contaminant Metal Speciation and Lability in Arid Lead-Zinc Sulfide Mine Tailings at the Klondyke Superfund Site, Graham County, AZ." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/196007.
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Historic mine tailings pose a significant health risk to surrounding ecosystems and communities because of high residual concentrations of contaminant metals. The initial tailings mineral assemblage, metal sulfides, silicates, and carbonates are unstable at earth surface conditions and undergo oxidative and proton-promoted weathering. The weathering of metal sulfides generally produces acid that, if not balanced by protonconsuming dissolution of silicates and carbonates, leads to progressive acidification. The Klondyke State Superfund Site in Graham County, Arizona contains high concentrations of Pb (up to 13 g kg⁻¹) and Zn (up to 6 g kg⁻¹), and remains unvegetated 50 years after mining cessation. Field-scale investigation revealed a wide range of pH (2.5-8.0) and plant-available (DTPA-extractable) metals in the near surface of the tailings pile. Four samples were chosen for in-depth characterization ranging in pH, as denoted by subscript, from 2.6 to 5.4. The mineral transformations occurring in these four samples were investigated using a variety of techniques and the data indicated an increase in tailings weathering extent with increasing acidification (decreasing pH). Lead speciation, studied by a combination of chemical sequential extraction and X-ray absorption fine structure (XAFS) spectroscopy, was found to vary with tailings depth. The principle lead-bearing mineral was plumbojarosite (PbFe₆(SO₄)₄(OH)₁₂), with smaller amounts of anglesite (PbSO₄) and lead-sorbed iron-oxide. Anglesite, the most bioavailable mineral form of Pb in the tailings, was found to accumulate at the tailings surface, which has important implications for health risks. Total Zn content decreased by an order of magnitude (from 6 to 0.4 g kg⁻¹) and showed a change in molecular speciation with decreasing pH. Zinc-rich phyllosilicates and Zn-containing manganese oxides predominate at high pH, whereas low pH samples contained principally Zn-sorbed iron oxides. One of the overarching goals of the project is to remediate the Klondyke site using phytostabilization to keep contaminant metals from eroding offsite either by wind or water transport mechanisms. However, the impacts of plant growth on metal bonding environment are unknown. To address that gap in knowledge, we have developed a technique for the study of root-microbe-mineral-metal interactions that occur in the rhizosphere, the volume of soil surrounding, and affected by, plant roots. This technique involves the conjunctive use of fluorescence in-situ hybridization, X-ray fluorescence elemental mapping, XAFS and Raman micro-spectroscopies, and electron microscopy on single roots. Manganese and iron root plaques collocalized with elevated Pb, Zn, and Cr demonstrate that the rhizosphere can affect metal speciation. Metal speciation is an important factor in determining metal bioavailability, and thus is critical for understanding the health risk associated with mine tailings. The results of this research provides site-specific information about Pb and Zn speciation, which will be used to evaluate the effectiveness of site remediation within the context of metal toxicity.
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Jonsson, Carl, and Isak Falkman. "Production Control in Underground Mines using Discrete EventSimulation." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-86162.
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The optimization of production has come a long way in the last few years. From having to implement new production philosophies directly into the production, today you can simply build a simulation on the computer that can be used to test new solutions. This makes it cheaper and less time-consuming to improve production. This report will describe the thesis work made by two students from Lulea University of Technology studying mechanical engineering with orientation production technology. The thesis work was made at Boliden MineralsAB during the spring term of 2021. This master thesis aim is to look at the potential of using discrete-event simulation as a tool to test different production philosophies. To do this, a simulation model is built to represent Boliden’s mining operation. The focus will be on the Cut and fill process, and how vehicles and operators are dispatched. From interviews, videos and information gave by Boliden a current state analysis was done to get a good understanding of the situation and how the process works. This combined with a litterateur study a good foundation was made to start building the simulation. Since this is the first time Boliden uses simulation on the cut and fill process in this manner, there’s been close contact with Boliden to validate and verify the models. The different production scenarios that were simulated were selected with the guidance of Boliden to look at the most relevant areas for them. Firstly, a base model was constructed, this model had a number of restrictions compared to the real-life process. With data from previous work that Boliden had with simulation models, the base model could be controlled that it worked properly. From this model others, models could be build-up, with the difference of using another production control philosophy for the simulation. By using these philosophies there could be determined an increase by 1% in productivity when prioritizing operators to the bottleneck of the process to maximize utilization.
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Veliz, Yañez Pedro Yunior. "Mejora en el proceso de recepción de camiones para un depósito minero utilizando la metodología Lean Six Sigma." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/653446.
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La empresa en estudio, dedicada a la logística integral de concentrados mineros tiene como uno de sus proceso principales la recepción de camiones con concentrado de Cu, Pb y Zn de las diferentes mineras del Perú cuya demanda diaria es de 170 camiones para lo cual se ha propuesto atenderlo en un periodo de 10 horas cuyo indicador del proceso es de 17 camiones/hora, pero actualmente se viene manejando un indicador en promedio de 15 camiones/hora, esto ocasiona que se incurra en sobrecostos tales como horas extras y utilización de recursos los que equivalen a un sobrecosto anual de S/. 638,655; por este motivo se proponen implementar dos herramientas de la metodología Lean Six Sigma. El diagnostico reveló que el problema del incumplimiento de indicador radica en la ineficiencia y eficacia del proceso de recepción, en el cual el tiempo total de los camiones en todo el circuito del proceso de recepción es alto en promedio 2.4 horas; el análisis causal halló causas raíces como áreas desordenadas, congestión en zona de toma de muestra y zona de descarga, tras lo cual se propone el despliegue de las herramientas propias de la metodología como la implementación de 5S que busca generar cultura de orden y limpieza con y la mejora del flujo de camiones entre etapas con la estandarización de procesos. Al realizar las implementaciones se estima reducir el tiempo promedio de camiones de 2.4 horas a 1.7 horas y optimizar los recursos y reducir los sobre costos.The company under study, dedicated to the integral logistics of mining concentrates has as one of its main processes the reception of trucks with concentration of Cu, Pb and Zn of the different miners in Peru whose daily demand is 170 trucks for which it has set out to serve it in a period of 10 hours whose indicator of the process is 17 trucks/hour, but currently an indicator of 15 trucks/hour has been handled, this results in overruns such as overtime and resource utilization which amount to an annual cost of S/. 638,655; for this reason, they intend to implement two tools of the Lean Six Sigma methodology. The diagnosis revealed that the problem of non-compliance with indicator lies in the inefficiency and effectiveness of the receiving process, in which the total time of trucks throughout the receiving process circuit is high on average 2.4 hours; the causal analysis found root causes such as disordered areas, congestion in sampling area and discharge zone, after which it is proposed the deployment of the methodology's own tools such as the implementation of 5S that seeks to generate culture of order and cleanliness with and the improvement of the flow of trucks between stages with the standardization of processes. When deploying, it is estimated to reduce average truck time from 2.4 hours to 1.7 hours and optimize resources and reduce over-costs.
Trabajo de Suficiencia Profesional
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Andrew, Anne. "Lead and strontium isotope study of five volcanic and intrusive rock suites and related mineral deposits, Vancouver Island, British Columbia." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26953.
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Lead isotope compositions have been obtained from five major volcanic and intrusive rock suites and several ore deposits on Vancouver Island. Lead, uranium and thorium concentrations and strontium isotope ratios have been obtained for a subset of these samples. The rock suites examined are the Paleozoic Sicker Group, Triassic Karmutsen Formation, Jurassic Island Intrusions and Bonanza Group volcanic rocks, and the Eocene Catface intrusions.
Isotope geochemistry of the Sicker Group is consistent with the interpretation that it formed as an island arc. Relatively high 207pb/204pb ratios indicate sediment involvement in the subduction process, which suggests that the Sicker Group formed close to a continent. Buttle Lake ore deposits display decreasingly radiogenic lead isotope ratios with time, suggesting that the associated magmas become increasingly primitive. This supports the hypothesis that these deposits formed during the establishment of rifting in a back-arc environment.
Karmutsen Formation flood basalts display isotopic mixing between an ocean island-type mantle source and average crust. Isotopic evidence is used to support a Northern Hemisphere origin for these basalts.
Mixing is apparent in the lead and strontium isotope signatures of the Island Intrusions and Bonanza Group volcanic rocks, between depleted mantle and crustal (possibly trench sediments) components. This is consistent with formation of these rocks in an island arc environment.
Eocene Catface intrusions have relatively high 207pb/204pb indicating that crustal material was involved in their formation. There are two groups of plutons corresponding to an east belt and west belt classification. Galena from the Zeballos mining camp related to the Eocene Zeballos pluton indicates that the mineralization was derived from the pluton.
Galena lead isotope data from Vancouver Island may be interpreted in a general way by comparison with data from deposits elsewhere of known age and origin. No single growth curve model can be applied. Lead isotope characteristics of Vancouver Island are clearly different from those of the North American craton, reflecting the oceanic affinities of this terrane.
A new technique has been developed to compare 207pb/204pb ratios between samples with differing 206pb/204pb ratios. The procedure projects 207pb/204pb ratios along suitable isochrons until they intersect a reference value of 206pb/204pb. This technique can be used for interpreting lead isotope data from old terranes, in which lead and uranium may have undergone loss or gain, and if lead and uranium abundances have not been measured.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
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Dutra, Pedro Henrique. "Distribuição do Pb-210 em sedimentos de bacias hidrográficas à mina de urânio de Caldas - MG." CNEN - Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, 2014. http://www.bdtd.cdtn.br//tde_busca/arquivo.php?codArquivo=324.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorO empreendimento das Indústrias Nucleares do Brasil INB Caldas, Minas Gerais, o primeiro complexo mínero-industrial de urânio instalado no Brasil e inaugurado em 1982, está em fase de fechamento e de descomissionamento. Esse empreendimento está situado a mina de urânio a céu aberto Osamu Utsumi e a usina de extração de minério de urânio. Em relação a esta área, está sendo desenvolvido o Projeto Caracterização, monitoramento da qualidade ambiental e recuperação de áreas degradadas pela indústria mineral, incluindo a recuperação de metais de resíduos e de efluentes industriais em uma das linhas de pesquisa do Instituto Nacional de Ciência e Tecnologia em Recursos Minerais, Água e Biodiversidade (INCT-Acqua). Dentre as diversas atividades deste projeto, está a avaliação da qualidade da água e sedimentos no entorno do empreendimento, no município de Caldas, levando em conta os focos de contaminação em potencial e a verificação de impacto da mina em termos da presença de radionuclídeos provenientes da série de decaimento radioativo natural do 238U. A área de estudo é constituída pela Bacia Hidrográfica do Rio Taquari, subdividida por seus três principais sub-bacias: córrego da Consulta, ribeirão Soberbo e rio Taquari. Assim, atendendo a um dos objetivos do projeto, foi realizado este estudo no qual visando verificar a distribuição de 210Pb no entorno da mina, onde os resultados de concentrações da atividade do radionuclídeo em amostras de sedimento coletadas em 4 campanhas, estações seca e chuvosa, em diversos pontos das sub-bacias, foram a base para ser aplicada a técnica de geoprocessamento utilizando as concentrações da atividade de 210Pb medidas. As medidas da concentração de atividade 210Pb foram obtidas por espectrometria gama em detectores de alta e de baixa energias. Para se comparar os resultados obtidos foi calculada a razão entre os resultados dos detectores e normalizados em relação às médias das razões por campanha. Em 12 pontos de coleta foram produzidos 48 resultados, sendo que deste total, 77,1% apresentaram afastamento de apenas 5% em relação à média das razões normalizadas, 12,5 % apresentaram afastamento maior do que 10%, sendo que destes 4,2% acima de 20% de afastamento. Baseando-se nestes percentuais, pode-se afirmar que o desempenho dos detectores foi similar. Assim, verificou-se que a determinação de 210Pb em amostras de sedimento pode ser realizada tanto em detector de alta energia do tipo HPGe com janela de carbono quanto no de baixa energia do tipo HPGe janela de berílio. Em termos de distribuição da atividade de 210Pb nas campanhas e por sub-bacia, pode-se verificar que a proximidade dos corpos dágua de pontos-fonte, descarga de um rio em outro, ações antropogênicas na área e sazonalidade influenciam na variação da concentração de atividade do radionuclídeo. Quanto à aplicação da técnica de geoprocessamento, ela foi útil ao mapear a distribuição espacial do radionuclídeo, realçando as áreas de maior concentração. Os resultados indicam que a mina Osamu Utsumi está influenciando na distribuição de 210Pb no seu entorno. Estudos mais detalhados devem ser conduzidos de modo a identificar ocorrência de anomalias geológicas na região, ainda não identificadas, poderiam estar contribuindo para o aumento da atividade de 210Pb. As medidas da concentração de atividade 210Pb foram obtidas por espectrometria gama em detectores de alta e de baixa energias. Para se comparar os resultados obtidos foi calculada a razão entre os resultados dos detectores e normalizados em relação às médias das razões por campanha. Em 12 pontos de coleta foram produzidos 48 resultados, sendo que deste total, 77,1% apresentaram afastamento de apenas 5% em relação à média das razões normalizadas, 12,5 % apresentaram afastamento maior do que 10%, sendo que destes 4,2% acima de 20% de afastamento. Baseando-se nestes percentuais, pode-se afirmar que o desempenho dos detectores foi similar. Assim, verificou-se que a determinação de 210Pb em amostras de sedimento pode ser realizada tanto em detector de alta energia do tipo HPGe com janela de carbono quanto no de baixa energia do tipo HPGe janela de berílio. Em termos de distribuição da atividade de 210Pb nas campanhas e por sub-bacia, pode-se verificar que a proximidade dos corpos dágua de pontos-fonte, descarga de um rio em outro, ações antropogênicas na área e sazonalidade influenciam na variação da concentração de atividade do radionuclídeo. Quanto à aplicação da técnica de geoprocessamento, ela foi útil ao mapear a distribuição espacial do radionuclídeo, realçando as áreas de maior concentração. Os resultados indicam que a mina Osamu Utsumi está influenciando na distribuição de 210Pb no seu entorno. Estudos mais detalhados devem ser conduzidos de modo a identificar ocorrência de anomalias geológicas na região, ainda não identificadas, poderiam estar contribuindo para o aumento da atividade de 210Pb.As medidas da concentração de atividade 210Pb foram obtidas por espectrometria gama em detectores de alta e de baixa energias. Para se comparar os resultados obtidos foi calculada a razão entre os resultados dos detectores e normalizados em relação às médias das razões por campanha. Em 12 pontos de coleta foram produzidos 48 resultados, sendo que deste total, 77,1% apresentaram afastamento de apenas 5% em relação à média das razões normalizadas, 12,5 % apresentaram afastamento maior do que 10%, sendo que destes 4,2% acima de 20% de afastamento. Baseando-se nestes percentuais, pode-se afirmar que o desempenho dos detectores foi similar. Assim, verificou-se que a determinação de 210Pb em amostras de sedimento pode ser realizada tanto em detector de alta energia do tipo HPGe com janela de carbono quanto no de baixa energia do tipo HPGe janela de berílio. Em termos de distribuição da atividade de 210Pb nas campanhas e por sub-bacia, pode-se verificar que a proximidade dos corpos dágua de pontos-fonte, descarga de um rio em outro, ações antropogênicas na área e sazonalidade influenciam na variação da concentração de atividade do radionuclídeo. Quanto à aplicação da técnica de geoprocessamento, ela foi útil ao mapear a distribuição espacial do radionuclídeo, realçando as áreas de maior concentração. Os resultados indicam que a mina Osamu Utsumi está influenciando na distribuição de 210Pb no seu entorno. Estudos mais detalhados devem ser conduzidos de modo a identificar ocorrência de anomalias geológicas na região, ainda não identificadas, poderiam estar contribuindo para o aumento da atividade de 210Pb
The Nuclear Industries of Brazil - INB Caldas, State of Minas Gerais, was the first mineral-industrial complex in Brazil. It has been installed since 1982 and at the moment it is under conclusion and decommissioning. This complex consists of an open air uranium mining called Osamu Utsumi, and a unit of process in the extraction of uranium ore. Concerning this area, a project Characterization, monitoring of environment quality and recovering of degraded areas by mining industry, including recovering metals from waste and industrial effluents is one of researches of National Institute for Science and Technology in Mining Resources, Water and Biodiversity (INCT-Acqua). Among the several activities of this project, it is related to the evaluation of water quality and sediment around the complex in Caldas, taking into account the potential sources of contamination and the assessment of the impact of the mine basing on the presence of radionuclides from the radioactive decay series of natural 238U.The study area consists of the Taquari watershed, sub-divided by its three major sub-basins: Consultation stream, Soberbo stream and Taquari river. Therefore, in order to answer one of the objectives of the project, this research was carried to verify the distribution of 210Pb around the mining. The radionuclide activity concentrations were measured in sediment samples that were collected during 4 campaigns, dry and rainy seasons, in several collecting points. The values were the data basis for applying the geoprocessing technique. The results of the 210Pb concentration activity were obtained by gamma spectrometry performed in a high energy detector and also low energy detector. In order to compare the results, the ratio between the measurements on detectors was calculated and normalized related to the average of the ratios per caper detector. Summarizing, in 12 sampling points, 48 results were obtained: 77.1% of the total presented distance of only 5% related to the normalized average; 12.5% presented distance higher than 10% (4.2% above than 20%). Basing on these results, it is possible to state that the detectors had similar performance. Therefore, it was possible to verify that the 210Pb determination in sediment samples can be carried out in both types of detector HPGe, one suitable for measuring high gamma energy with composed carbon window and other suitable for low gamma energy with beryllium window. In relation to the distribution of 210Pb activity during the campaigns, it was possible to verify the influence of the proximity of the water bodies to source-points, discharge of a river into another, anthropogenic activities in the area and seasonality on the variation of the concentration of the radionuclide activity. The use of geoprocessing technique was useful mapping the spatial distribution of 210Pb activity. In the maps, the areas with higher activity were enhanced. The results point out that the Osamu Utsumi mining is influencing on the distribution of 210Pb activity in its neighbourhood. However, more detailed study should be done in order to identify if there is another source of 210Pb like geological anomaly occurrence in the region that may contributing to the 210Pb activity.
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Huaira-Perez, Jorge, Orlando Llerena-Vargas, Humberto Pehóvaz-Alvarez, Hugo Solis-Sarmiento, Vidal Aramburu-Rojas, and Carlos Raymundo. "Lean Six Sigma Fleet Management Model for the Optimization of Ore Transportation in Mechanized Underground Mines in Peru." Universidad Peruana de Ciencias Aplicadas (UPC), 2021. http://hdl.handle.net/10757/653823.
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El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.Mining activities around the world are undergoing constant change and modernization owing to technological and scientific advancements. Consequently, there are frequent proposals to streamline and enhance processes in mining operations. This study deals with ore transportation in mechanized mining units and aims to optimize fleet management using the Lean Six Sigma methodology to obtain a model in this specific process. The proposed method was implemented using a Lean Six Sigma instrument known as DMAIC (Define, Measure, Analyze, Improve, and Control). The case study was applied to an underground mine located in the Huancavelica region, Peru. The simulation showed that 24% of the time in the ore transport cycle is un-productive time and the improvement potential time represents 53% of the transportation process time.
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Ranford, Jonathan J. "The impact of tropospheric ozone on Ilex aquifolium L., its leaf-miner (Phytomyza ilicis Curt.) and its parasites." Thesis, Staffordshire University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438085.
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Socías, Salas Natacha Isabel. "Propuesta de mejora para el desarrollo de ingeniería pre-inversional de un proyecto minero utilizando el enfoque lean management." Tesis, Universidad de Chile, 2017. http://repositorio.uchile.cl/handle/2250/145337.
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Ingeniera Civil IndustrialEn la actualidad, la minería se ve enfrentada a un escenario crítico debido a la caída en el precio del cobre; menores rendimientos del mineral; agotamiento de recursos explotables y una fuerte baja de la productividad. Ante tal situación, Codelco, Corporación Nacional del Cobre de Chile, ha declarado iniciar un proceso transformador en sus procesos operacionales mediante la utilización de la filosofía Lean, filosofía que identifica las actividades que generan valor y elimina o disminuye las que no lo aporten, consideradas desperdicios. Codelco, mediante los servicios de Boston Consulting Group ha identificado los procesos críticos sobre los cuales influir para obtener la productividad deseada, siendo uno de éstos el desarrollo de ingeniería pre-inversional, proceso a cargo de la Vicepresidencia de Proyectos. Es en este punto donde surge la motivación por realizar este trabajo, con el objetivo de proponer mejoras sobre el desarrollo de ingeniería de Prefactibilidad, una de las etapas más críticas dentro del desarrollo de ingeniería pre-inversional porque establece las bases del futuro proyecto en construcción. Además, la literatura ha demostrado que buenas decisiones y definiciones en etapas conceptuales generan un gran impacto en el cumplimiento del presupuesto y manejo ante las posibles dificultades en la ejecución del proyecto. Para lograr el objetivo se ha considerado el estudio de bibliografía que incorpore herramientas de diseño, control y gestión de la filosofía Lean Management. Además, se analiza un caso de estudio de un proyecto minero, con el fin de levantar las principales problemáticas en el desarrollo de ingeniería de Prefactibilidad. El caso de estudio corresponde al proyecto Aumento de Capacidad de Tranque de Relaves de Talabre, tranque encargado de recibir los relaves de las Divisiones: Chuquicamata, Radomiro Tomic y Ministro Hales. Del caso estudiado, se realiza un diagnóstico de problemas, donde se obtienen las 2 problemáticas más relevantes dado un análisis de riesgos mediante la realización de una Matriz de Riesgos. Estas problemáticas corresponden a: falta de definiciones y estándares claves al inicio del proyecto y reuniones poco efectivas, las cuales son abordadas en la propuesta final del presente trabajo mediante el diseño de 2 herramientas basadas en la filosofía Lean Management: BEAM y Obeya Room. Estas herramientas ayudan a generar una mejor gestión integral del proyecto y son posibles de aplicar y adaptar a cualquier tipo de proyecto, con su respectiva actualización de información dada a la naturaleza del negocio. Finalmente, se proponen ciertas recomendaciones para lograr un cambio organizacional que lleve hacia una mejora en la productividad mediante la aplicación de herramientas de la Filosofía Lean Management, el cual está altamente determinado por la existencia de agentes de cambio, personas con conocimientos de las herramientas Lean, que sean capaces de motivar el cambio en la cultura organizacional, y promover la mejora continua.
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Aristizabal, Catalina. "Arbuscular Mycorrhizal Fungi Enhance the Acquisition of Mineral Nutrients from Leaf Litter by Morella cerifera." Scholarly Repository, 2008. http://scholarlyrepository.miami.edu/oa_dissertations/94.
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Morella cerifera (L.) Small, the Wax Myrtle, forms both arbuscular mycorrhizas and cluster roots which generally are regarded as alternative adaptations for phosphorus acquisition. But whether or not arbuscular mycorrhizal fungi (AMF) provide any benefit to M. cerifera is not known. Nevertheless, AMF can proliferate extensively within the litter leaves that accumulate beneath M. cerifera. The main objective of this study was to determine if AMF are beneficial to M. cerifera host plants in the presence of leaf litter. In the field, I examined leaf traits that affect the colonization of leaf litter by AMF. I compared AMF colonization of labile versus recalcitrant leaves, and that of leaf pieces with obstructed versus non-obstructed veins. In pot experiments, I examined if labile or recalcitrant litter influences the potential benefit of AMF to M. cerifera, and if nitrogen (N) or phosphorus (P) fertilization influences that benefit in the presence of recalcitrant leaf litter. I found that AMF extensively colonize both labile and recalcitrant leaves, but that they colonize labile leaves more rapidly than recalcitrant leaves. I found significantly less colonization in leaf pieces with obstructed veins than in those with non-obstructed veins which suggests that penetration by the fungi primarily is mechanical and not enzymatic. The pot experiments showed that AMF are parasitic on M. cerifera except when recalcitrant leaf litter is present, and that the effects of AMF on M. cerifera are indirect and mediated through effects of AMF on N-fixing nodule dry weight. In both pot experiments, AMF enhanced litter decomposition and may have enhanced plant P-nutrition. AMF benefited M. cerifera growth in the absence of N fertilization but negatively affected M. cerifera growth when N was added. In the presence of litter, inoculation with AMF increased cluster root formation, suggesting that these two adaptations may be complementary in extremely nutrient-poor soils. Overall, this study shows that M. cerifera does benefit from association with AMF, and it suggests that AMF play a more important role in the acquisition of mineral nutrients from leaf litter than previously recognized.
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Villarroel, Valle Cristián Enrique. "Aplicación de Lean Management en una mina rajo abierto División El Teniente - Codelco Chile." Tesis, Universidad de Chile, 2015. http://repositorio.uchile.cl/handle/2250/137312.
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Autor no autoriza el acceso a texto completo de su documento hasta el 11/9/2020.Magíster en Gestión y Dirección de Empresas
El presente trabajo muestra la implementación de la metodología LEAN, como una forma de gestión, aplicada a resolver la problemática de aumento de Utilización Efectiva de los Camiones de Extracción (CAEX), de Mina Rajo Sur, que posee costos de extracción mayores a la industria. Dicho proceso de Transporte representa del orden del 40% al 60% de los Costos Mina Rajo, y cualquier mejora, influye directamente en el costo C0 de División El Teniente. La aplicación LEAN, con iniciativas de organizar, controlar y estandarizar procesos como el Sistema de Despacho Jigsaw, que mejoró la utilización de la asignación dinámica, como el Abastecimiento de Combustible, que significó Cero aumento de inversión de capital (Capex) y/o gasto operacional (Opex), aumentando las horas efectivas de los CAEX. Los resultados obtenidos en el caso del Uso de la Asignaciones Dinámicas de los CAEX, supero el 90% de utilización de los 4 grupos de operaciones mina, y se tornó un estándar para el trabajo diario. La disminución del porcentaje de combustible remanente, que bordeaba el 60% antes de aplicar LEAN, logró una baja entre el 20 a 25%, en base a la estandarización y reglamentación, disminuyendo las veces que un CAEX asistía a la estación de servicio, ganando horas efectivas día (disminución de las detenciones). La implementación de un Casino en un punto estratégico de la trayectoria de los CAEX y Naves de Relevo, significó un aumento en la UEBD de 70% a 74%, logrando un aumento en la productividad de 40 ktpd a 43 ktpd. Los resultados obtenidos, dan cuenta de la importancia de la herramienta LEAN, trabajando con un equipo compuesto por Operadores, Supervisión y Dirigentes Sindicales, etc., instaurando la excelencia operacional como una forma de trabajar. El seguimiento de los resultados en base a los Diálogos de Desempeño & Retroalimentaciones, son expuestos semanalmente a la Operación Rajo, en forma visual en pantallas LED, han logrado mantener UEBD, en base a la estandarización de los procesos. Esto debe ser una forma de trabajar en la Administración de una Gerencia o Empresa, en que se logre trasferir el valor de LEAN .en todas las personas, en todo momento y en todo lugar. Finalmente, si bien aún queda espacios de mejoramientos para llegar a la excelencia operacional en Rajo Sur, la organización, lo más importante, está convencida que los resultados a la fecha, encaminan a un buen logro y sobre todo superando el objetivo de este trabajo.
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Päivöke, Aira E. A. "Responses of Pisum sativum to soil arsenate, lead and zinc a greenhouse study of mineral elements, phytase activity, ATP and chlorophylls." Helsinki : University of Helsinki, 2003. http://ethesis.helsinki.fi/julkaisut/mat/bioti/vk/paivoke/.
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Gustafsson, Marcus, and Patrik Bergström. "Cirkulär ekonomi i kombination med Lean för att förbättra hållbarheten i bergtäkter." Thesis, Karlstads universitet, Institutionen för ingenjörs- och kemivetenskaper (from 2013), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-85958.
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Stone is a useful resource, for example as a building material, which means that stone materials play a large role in the construction of society. Stone is mined and refined in so-called quarries. There are activities in quarries that have negative impact on the environment. In addition, such industries have traditionally consumed a substantial amount of fossil fuel. Due to these aspects, among others, the quarrying industry should become more sustainable. Circular economy has the fundamental idea of reducing, reusing and recycling, and can be useful for improving sustainability. To make a business more sustainable, all parts of it should improve in this aspect, including the processes. Process improvement is a strong area of the Lean, which strives to create flow and to remove everything that interferes with the flow. The purpose of the study was to obtain a deeper understanding of how quarries can be improved from a sustainability perspective with a combination of circular economy and Lean. This by reviewing previous theory of sustainability, circular economy, Lean and other relevant areas. The study was carried out as a qualitative case study at, and in collaboration with, a quarrying company in Sweden. The data collection consisted of interviews with relevant people from the company and observations of quarries. The results were compared with the theoretical framework to answer the formulated research questions. The study resulted in several conclusions, the most fundamental is that increased awareness and knowledge about sustainability would bring better possibilities for the company in its work towards a more sustainable busiss. According to the company investments must yield economic profitability, and hence a large responsibility is laid on the customers to demand sustainable products. Permissions and regulations are, according to the interviewees, obstacles to increased recycling of stone materials, and consequently obstacles to circular economy. An adjustment of permissions to allow more reuse of materials would benefit circular economy. Lean is not entirely applicable due to the long lead times in quarries. However, some aspects of Lean are useful, especially its focus on minimizing wastes. An approach characterized by a circular mindset and by process improvement can be adopted with a combination of circular economy and Lean. Overall, quarrying needs to be seen from a holistic perspective and the communication between all parties in the distribution chain needs to be improved.
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Belin, Joffrey. "Fabrication de filtres interférentiels par dépôt PECVD pour l'éclairage LED." Mémoire, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/10670.
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Grâce à leur haute efficacité et leur durée de vie plus longue, les LED sont de plus en plus utilisées pour l’éclairage, et particulièrement depuis ces dernières années, pour l’éclairage public. Toutefois, le spectre d’émission d’une LED diffère de celui d’une ampoule à incandescence ou à décharge, avec notamment des longueurs d’onde dont l’amplitude est plus élevée dans le domaine du bleu. Il a été démontré que ces longueurs d’onde bleues réduisent la sécrétion de mélatonine, une hormone qui, en plus de ses propriétés anti-oxydantes et anti- cancérigènes, permet de réguler l’horloge biologique du corps humain. La carence de mélatonine peut provoquer des états de fatigue et de stress, pouvant conduire dans certains cas à la dépression. Les longueurs d’onde rouges et proche-IR issues d’éclairages LED ou incandescent ont également des effets négatifs sur l’environnement, puisqu’elles perturbent les cycles de la végétation, comme la photosynthèse. Ces problèmes de santé publique sont connus des autorités, si bien qu’elles imposent des normes pour réduire l’émission de longueurs d’onde bleue, rouge et proche-IR issues de l’éclairage public (ex. norme BNQ 4930-100 au Québec). Dans ce projet, nous proposons des filtres interférentiels permettant d’éliminer les longueurs d’onde nuisibles issues d’un éclairage LED, sans impacter la qualité et l’efficacité de cet éclairage. En utilisant la technique de dépôt PECVD (Plasma Enhanced Chemical Vapor Deposition), nous avons développé des matériaux optiques innovants qui permettent de réaliser des filtres efficaces, simples et à faible coût.
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Brännström, Moa. "Utredning av alternativ för kostnadseffektivare pumpreparationer : vid Boliden Mineral AB:s gruva i Renström." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-72731.
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Företaget Boliden är världens främsta producent av zink och ledande i Europa medproduktion av koppar och nickel.För att nå malmen under jord drivs ramper och orter genom borrning, sprängningoch bergförstärkning. Dessa arbetsmoment kräver att stora mängder vatten tillförs,bland annat för att binda dammet som uppstår vid arbetsmomenten och även för attkyla maskinerna. Vattnet som är i omlopp i gruvan hanteras av länspumpar, sompumpar vattnet runt i gruvan eller upp till reningsverk.Bolidens gruva i Renström har länge haft problem med pumparna under jord, bådegällande den låga tillgängligheten och höga reparationskostnader. Syftet med dennarapport är att analysera och utvärdera möjligheterna att minska de kostnader somfinns kopplat till trasiga pumpar. Det slutgiltiga målet är att utvärdera och gekonkreta rekommendationer på hur Boliden Renström kan hantera de trasigapumparna i framtiden. De avgränsningar som fastställts är att enbart ganskaprocessflödet från när trasiga pumpar anländer till nivå 1125 tills de är tillbakareparerade på nivå 1125. Vissa ekonomiska faktorer som är svårbedömda kommeratt baseras på grova beräkningar och antaganden.Med hjälp av observationer och intervjuer ritades ett värdeflöde över nuläget.Värdeflödesanalysen och Lean’s teorier om slöseri jämfördes för att hitta onödigamoment i nuläget. Förbättringsåtgärder togs fram för att eliminera det slöseri somfanns. Dessa förbättringsåtgärder är; Minska antalet pumpar i flödet Ställa högre reparationsvillkor på den interna reparatören Hantera pumpar styckevis istället för stora partistorlekar Ändra beställningsrutinerna i Maximo Vidare analyserades tre olika framtida tillstånd för pumpreparationerna; reparerabåde internt och externt, endast reparera internt eller endast reparera externt. Dessatre framtida tillstånd analyserades med SWOT-analyser för att se dess fördelar och nackdelar.Rekommendationen som lämnas är att reparera alla pumpar internt, då det är detbilligaste alternativet samt har kortare ledtid än nuläget. Enligt SWOT-analysenframkom några svagheter och hot, dessa bör Boliden Renström se över innan någrabeslut tas. En avslutande rekommendation är att se över om det finns möjlighet attendast jobba med en serie av pumparna och dess modeller, anpassat efterverksamhetens behov.De framtida studier som lämnas till företaget är att se över om det är möjligt attordna en gemensam verkstad för Bolidenområdets pumpar. Vidare skulle det ävenvara intressant att se vad resultatet blir om pumpstyrning och fasföljdstyrninginstalleras i pumparna.
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Arriagada, Hernández Pablo Andrés. "Incorporación de metodologías de Lean Management en la etapa de construcción de la mina Recursos Norte." Tesis, Universidad de Chile, 2018. http://repositorio.uchile.cl/handle/2250/169953.
Full textAbstract:
Tesis para optar al grado de Magíster en Gestión y Dirección de EmpresasLa disminución de disponibilidad de mineral a partir del año 2021 producto del retraso en la puesta en marcha del Proyecto Nuevo Nivel Mina (PNNM) significó que División El Teniente tuviera que definir un Plan de Desarrollo Alternativo (PDA) que permitiera mantener los actuales ritmos de producción, que bordean las 137.000 t/d como promedio anual. De esta forma, el PDA considera la puesta en producción de tres nuevos sectores asociados a la mina subterránea, junto con una primera etapa del PNNM, con plazos de ejecución exigentes debido a la necesidad de asegurar la cobertura de mineral. El Proyecto Recursos Norte, perteneciente al PDA, instala el desafío de construir una mina de gran tamaño en tiempos menores a los que la División ha logrado concretar en proyectos anteriores de similares características, planteando el reto de desarrollar una forma diferente de encarar la construcción de una mina subterránea de modo de incrementar los indicadores de productividad de la actividad. El objetivo general del presente trabajo de tesis consistió en elaborar una propuesta de implementación de metodologías de Lean Management y Excelencia Operacional en el desarrollo de las obras tempranas del Proyecto Recursos Norte, con el objetivo de mejorar los rendimientos exhibidos por la empresa constructora y sentar las bases de un esquema de operación estandarizado para la ejecución de otros proyectos de construcción de mina. Para ello, se seleccionaron y desplegaron al interior del equipo de construcción del Proyecto una serie de metodologías y herramientas, y se evaluó su impacto entre los meses de mayo y diciembre de 2017. Los resultados logrados mediante el despliegue de estas metodologías evidenciaron una mejora relevante en los indicadores de productividad del contrato, sustentado en la gestión de interferencias e implementación de mecanismos de resolución de problemas que permitieron incrementar los tiempos efectivos de trabajo. A su vez, se dio una especial relevancia a los aspectos organizacionales relacionados con la implementación de este tipo de metodologías, de modo que su aplicación no respondiera a un lineamiento temporal si no que a un esquema estandarizado y asumido en el seno del equipo de construcción del Proyecto. Los beneficios evidenciados brindan un impulso a la estandarización de las metodologías de trabajo implementadas para su uso en otros proyectos de construcción de mina subterránea, aprovechando el aprendizaje adquirido y profundizando su aplicación mediante la adición de nuevos elementos. Es así como el uso de este tipo enfoques se convierte en un pilar para asegurar e incluso adelantar la puesta en producción de las nuevas minas subterráneas respecto de su fecha planificada, contribuyendo directamente en la sostenibilidad de la Corporación durante los próximos años.
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Hands, Stuart Thomas. "Tritrophic interactions between the leaf miner, Liriomyza bryoniae (Kaltenbach) (Diptera: Agromyzidae) and the parasitoid, Diglyphus isaea (Walker) (Hymenoptera: Eulophidae)." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/3950/.
Full textAbstract:
Liriomyza bryoniae is an economically important pest of vegetable and ornamental crops in European glasshouse agriculture. Diglyphus isaea is a parasitoid of Liriomyza leaf miners and is commercially available as a biological control agent. Anecdotal reports made to commercial producers of the parasitoid suggest that the efficacy of D. isaea varies between crops. This study examines the tritrophic interactions between crop plant, L. bryoniae and D. isaea. Host plant was found to influence the abundance of L. bryoniae and D. isaea with larger populations establishing in the culturing host than in the novel host, tomato. Individual size of L. bryoniae also varies with host plant. These patterns are consistent in L. bryoniae across three generations of rearing on tomato. Habituation of L. bryoniae to tomato does not affect D. isaea efficacy nor does the natal plant host of D. isaea. Both L. bryoniae and D. isaea are affected by plant host ontogenetic stage, becoming most numerous on juvenile plants. The D. isaea natal insect-plant complex showed no effect on D. isaea olfactory preferences. Diglyphus isaea demonstrated greater thermal tolerance than its host. These results are discussed in relation to biological control and also in terms of their wider ecological implications.