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The circular economy is promoted by the EU, governments, and businesses all over the world as a concept to reach a sustainable future. The concept is embedded into the UN Sustainable Development Goals for 2030 and aims to decouple economic growth and environmental pressure. Many studies have been conducted on the circular economy in recent years but the research on the actual environmental performance of the concept is limited. To move forward with the concept of the circular economy and reach a sustainable future, the environmental performance must be investigated. In this thesis, the environmental impact of circularity in products is investigated by comparing the environmental impact from one circular and one linear product case. To achieve this, the environmental impact and the degree of circularity is calculated with two different methods. The circularity is calculated with a circularity indicator called the Linear Flow Ratio and the environmental impact is assessed with the environmental evaluation technique Life Cycle Assessment (LCA). In the LCAs, the cases are compared for different environmental impact categories (e.g. global warming). The product that is investigated is an LED lighting fixture from the company 2P1. The circular case is based on a leasing business model and includes remanufacturing, reuse and recycling. The linear case includes production, sales, use, and disposal. The LCA results show that the environmental impact from the circular case is lower for all environmental impact categories. The environmental impact is almost exclusively from the manufacturing phase (including extraction and production of raw materials) and the use phase. The circularity results from the Linear Flow Ratio show contradicting results, presenting that the degree of circularity is higher for the linear case. By comparing the results to calculations from another circularity indicator (Material Circularity Indicator), it is concluded that a unified framework for circularity measurements is required. / Cirkulär ekonomi är introducerat av EU, länder och företag över hela världen som ett koncept för att nå en hållbar framtid. Den cirkulära ekonomin är en del av arbetet mot agenda 2030 för hållbar utveckling och strävar efter att frånkoppla ekonomisk tillväxt från miljöpåverkan. Det har forskats mycket på cirkulär ekonomi under de senaste åren men studier som undersöker det miljömässiga utförandet av konceptet saknas. För att fortsätta att utveckla konceptet och för att nå en hållbar framtid så måste den miljömässiga påverkan från cirkularitet undersökas. I denna studie undersöks miljöpåverkan från cirkularitet hos produkter genom att jämföra miljöpåverkan från ett cirkulärt och ett linjärt fall. Miljöpåverkan och cirkularitetsgraden beräknas med två olika metoder. Cirkulariteten beräknas med cirkularitetsindikatorn Linear Flow Ratio och miljöpåverkan analyseras men livscykelanalys. I livscykelanalyserna värderas miljöpåverkan för de två fallen för olika påverkanskategorier (t.ex. global uppvärmning). Produkten som undersökt är en LED-armatur från företaget 2P1. Det cirkulära fallet basers på uthyrning av armaturerna och innehåller renovering, återanvändning och återvinning. Det linjära fallet innehåller produktion, försäljning, användning och bortskaffande av produkten. Resultaten från livscykelanalyserna visar att det cirkulära fallet medför mindre miljöpåverkan för alla kategorier. Miljöpåverkan kommer nästan enbart från produktion (inklusive material) samt användning. Cirkularitetsresultaten från Linear Flow Ratio visar motsägelsefulla resultat då det linjära fallet har en högre cirkularitetsgrad än det cirkulära fallet. Genom att jämföra resultaten med beräkningar från en annan cirkularitetsindikator (Material Circularity Indicator) kan det fastställas att ett enhetligt ramverk för beräkning av cirkularitet är nödvändigt framöver.

The increase of the industrial pollution has been carrying the organs of environmental control to review the legislation in force and to limit in a more rigorous form the discards of industrial effluent. As opposed, the companies have been improving the treatment systems of their effluent, applying new technologies. In the petroleum industry, in the oil-water separation, are used floatation chamber and hydrocyclones. The floatation seeks to recover the oil residue through gravitational separation, while the hydrocyclones try to accelerate this process with the use of the centrifugal force. The hydrocyclones in study are equipment constituted of a cylindrical part and two conic parts joint, in which the supply is constituted by two entrances involute, diametrically opposite, presenting a normal axis to the equipment and positioned tangentially to the lateral wall of the cylinder. The separator has two openings for exit, axis positioned to the equipment, one of them, called overflow, placed near to the supply section and to another, called underflow, placed near to the vertex of the conic body of the hydrocyclone. The analysis of the fluid-dynamic behavior of the hydrocyclone was led through the numeric simulation of the treatment of water produced, applying methods of Computational Fluid-dynamic (CFD). In the used computational tool, CFX, it is possible to build the geometry, draw the numeric mesh, adjust the simulation parameters, solve and to analyze the results, being able to be applied for several kinds of flow. It accomplished an experimental planning with the goal of analyzing the influence of the geometry in the separation efficiency of the hydrocyclone, in other words, know which variables were more important for the separation efficiency. To evaluate the performance of the equipment were calculated the Flow Ratio (Rf) and the Reduced Grade Efficiency (G ), for each geometry. Due to the great number of tested variables, whatever Dc, Do, Du, Hc, VF e L1 it opted to not analyze the effect of each one in separated, but the interactions of these. The different numeric simulations were considered as computational experiments. In all the 19 computational experiments, the simulations were initiated with the turbulence model k-e, these last used as initial values for the simulations with the turbulence model SSG, because this last is what best represents the flow in the hydrocyclone. The analyses done in the Essential Regression show that the variables which the most influence the separation efficiency are the overflow and underflow diameters. The reduced grade efficiencies stayed well distributed in the range 0-96%, what shows that the choice of the size of tried drop (250 mm) was adequate. The greatest reason values of fluid were obtained for Do/Du @ 1.0 and the minors, excluding Rf = 0, for Do/Du @ 0.2. In the studied intervals, the greatest Reduced Grade Efficiency values are obtained with the biggest values of Do and the smallest of Du. The smallest results of Flow Ratio are obtained with the smallest values of Do and the biggest values of Du. / O aumento da poluição industrial tem levado os órgãos de controle ambiental a rever a legislação em vigor e a limitar de forma mais rigorosa o descarte de efluentes industriais. Em contrapartida, as empresas têm melhorado os sistemas de tratamento de seus efluentes, aplicando novas tecnologias. Na indústria de petróleo, na separação óleo-água, são usados flotadores e hidrociclones. A flotação procura recuperar o resíduo de óleo através de separação gravitacional, enquanto que os hidrociclones procuram acelerar este processo com o uso da força centrífuga. Os hidrociclones em estudo são equipamentos constituídos de uma parte cilíndrica e duas partes cônicas justapostas, nas quais a alimentação é constituída por duas entradas em voluta, diametralmente opostas, apresentando um eixo normal ao do equipamento e posicionada tangencialmente à parede lateral do cilindro. O separador tem duas aberturas para saída, posicionadas axialmente ao equipamento, uma delas, chamada overflow, situada próxima à seção de alimentação e a outra, chamada underflow, situada próxima ao vértice do corpo cônico do hidrociclone. A análise do comportamento fluidodinâmico do hidrociclone foi conduzida através da simulação numérica do tratamento da água produzida, aplicando-se métodos de Fluidodinâmica Computacional (CFD). Na ferramenta computacional utilizada, CFX, é possível construir a geometria, desenhar a malha numérica, ajustar os parâmetros de simulação, resolver e analisar os resultados, podendo ser aplicado para diversos tipos de escoamento. Realizou-se um planejamento experimental com o objetivo de analisar a influência da geometria na eficiência de separação do hidrociclone, ou seja, saber quais variáveis eram mais relevantes para a eficiência de separação. Para avaliar o desempenho do equipamento foram calculadas a Razão de Fluido (Rf) e a Eficiência Granulométrica Reduzida (G ), para cada geometria. Devido ao grande número de variáveis testadas, quais sejam Dc, Do, Du, Hc, VF e L1 optou-se por não analisar o efeito de cada uma em separado, mas a interações destas. As diferentes simulações numéricas foram consideradas como experimentos computacionais. Em todos os 19 experimentos computacionais, as simulações foram iniciadas com o modelo de turbulência k-, estas últimas utilizadas como valores iniciais para as simulações com o modelo de turbulência SSG, pois este último é o que melhor representa o escoamento no hidrociclone. As análises feitas no Essential Regression mostram que as variáveis que mais influenciam a eficiência de separação são os diâmetros de overflow e de underflow. As eficiências granulométricas reduzidas ficaram bem distribuídas na faixa 0-96%, o que mostra que a escolha do tamanho de gota testado (250 mm) foi adequada. Os maiores valores de razão de fluido foram obtidos para Do/Du @ 1,0 e os menores, excluindo-se Rf = 0, para Do/Du @ 0,2. Nos intervalos estudados, os maiores valores de Eficiência Granulométrica Reduzida são obtidos com os maiores valores de Do e os menores de Du. Os menores resultados de Razão de Fluido são obtidos com os menores valores de Do e os maiores valores de Du.

The following study presents an experimental and computational investigation on the effects of implementing a dual cavity slashface configuration and varying slashface coolant leakage mass flow rate on the thermal performance for a 1st stage nozzle guide vane axisymmetric converging endwall. An upstream doublet staggered cylindrical hole jet cooling scheme provides additional purged coolant with consistent conditions throughout the investigation. The effects are measured in engine representative transonic mainstream and coolant flow conditions where Mexit = 0.85, Reexit = 1.5 × 106, freestream turbulence intensity of 16%, and a coolant density ratio of 1.95. Four combinations of slashface Fwd and Aft cavity mass flow rate are experimentally analyzed by comparing key convective heat transfer parameters. Data is collected and reduced using a combination of IR thermography and a linear regression technique to map endwall heat transfer performance throughout the passage. A flow visualization study is employed using 100 cSt oil-based paint to gather qualitative insights into the endwall flow field. A complimentary CFD study is carried out to gather additional understanding of the endwall flow ingestion and egression behavior as well as comparing performance against a conventional cavity configuration. Experimental comparisons indicate slashface mass flow rate variations have a minor effect on passage film cooling coverage. Instead, coolant coverage across the passage is primarily driven by upstream purge coolant. However, endwall heat transfer coefficient is reduced as much as 20% in mid-passage areas as leakage flow decreases. This suggests that changes in leakage flow maintains a first order correlation in altering passage aerodynamics that, despite relatively consistent film cooling coverage, also leads to significant changes in net heat flux reduction in the passage. Endwall flow behavior proves to be complex along the gap interface showing signs of ingestion, egression, and tangential flow varying spatially throughout the gap. CFD comparisons suggests that a dual cavity configuration varies the gap static pressure distribution closer to the mainstream pressure throughout the passage in high speed applications compared to a single cavity configuration. The resulting decelerating flow creates a more stable endwall flow profile and favorable coolant environment by reducing boundary layer thinning and shear interaction in near gap endwall tangential flow. / Master of Science / Gas turbines are often exposed to high temperatures as they convert hot, energetic gas streams into mechanical motion. As turbines receive higher temperature gases, their efficiency increases and reduces waste. However, these temperatures can get too hot for turbine parts. To survive these high temperatures, turbine components are often assembled with a gap in between to allow the part to expand and contrast when it heats and cools. Relatively cold air is also fed into the gap to help prevent hot gases from entering. This cold air can also feed into other pathways to flow onto the turbine component's surface and act as an insulating layer to the hot gas and protect the component from overheating. The study presented investigates an assembly gap, referred to as a slashface gap, found in the middle of a vane located immediately after gas combustion with cold air leaking through. One unique aspect of this study is that there are two pathways for cold air, or coolant, to leak through when, typically, there is only one. The slashface gap lies on a wall which the vanes are attached to, referred to as the endwall. Multiple small holes on the endwall in between the combustor and vanes jet out coolant to try and protect the endwall from hot gases. These holes, called jump cooling holes, point out towards the vanes and angled more shallowly so that the holes do not face directly up from the endwall. The holes are angled as they are meant to gracefully spray coolant to cover and insulate the endwall instead of mixing with the hot air above. The experiments found that changing how much coolant is leaked through the slashface has little effect on how much coolant from jump cooling holes covered the endwall. However, smaller slashface leaks better protect the endwall from the hot gas by forcing it to move smoother and give off less heat across the endwall rather than a tumbling like manner. The experiment is modeled on a computer simulation to determine the differences of a slashface gap with the typical one coolant pathway and the coolant dual pathway configuration that is tested in the experiments. This simulation discovered that having two coolant pathways significantly reduces how much hot gas and jump cooling coolant enters and leaves the slashface gap. This makes the surrounding airflow along the endwall travel more smoothly and does not give off as much heat as if a single coolant pathway configuration is used instead.

The objective of this thesis is evaluation of financial health of Pilkington Czech s.r.o. by using chosen methods of financial analysis. It contains concepts of potential solutions of discovered problems, which have to lead in the future to the improvements of financial situation of the company.

This diploma work assess the financial health of the company in the years 2002–2006 on the basis of selected methods of the financial analysis. It includes proposals of possible solutions of identified problems which should result in the improvement of financial situation of the firm in the following years.