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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

<strong>Lifecycle of social networks: A dynamic analysis of social capital accumulation</strong>

Munasib, Abdul B. A. 10 August 2005 (has links)
No description available.
22

Sustainability evaluation of proposal for a decentralized office space. : Case study, Växjö, Sweden

Frenliden, Carl, Ljungman, Martin January 2022 (has links)
As the COVID-19 pandemic became widespread around the world, the need to be able to work from home became clear to help reduce the spread of the virus, while at the same time showing that working from home could be successful in the future. While working from home can be positive, it also has drawback as reduce social interactions, hard to set working boundaries and more. This paper examines the viability to introduce a decentralized office space trough environmental sustainability, economic sustainability and social sustainability for a reference apartment building and an energy renovated one compared to a centralized office space. This study shows that working from a decentralized office space will reduce emissions with better utilization of the apartment building, saving the companies money and having a reasonable payback period for investors, while giving employees better personaleconomic and more free time without compromising on the social sustainability from not meeting people and having a hard time to different on working hours and non-working hours.
23

Life Cycle Cost of Smart Wayside Object Controller / Livscykelkostnad av Smart Wayside Object Controller

Zarov, Filipp January 2021 (has links)
In a regional railway signalling system, object controllers are the devices responsible for controlling Track Side Equipment and act as interfaces for TSE with the interlocking computer and the Traffic control system. However, associated cabling (signal and power cabling) and civil works pose a major capital investment and it is a source of significant Capital and Operational expenses, particularly in rural areas, where accessibility andconnectivity to power grid and to the interlocking are a problem. Furthermore, cables/signalling equipment are exposed to sabotage and theft in such areas. This can increase the total Life Cycle Cost even further. The Shift2Rail research programme, which was initiated by the European Union and railway stakeholders, tries to address this issue, and revamp the Object Controller concept through the project “TD2.10 Smart radio connectedwayside object controller”, where the aim is to develop a Smart Wayside Object Controller (SWOC). A SWOC is capable of wireless communication between central interlocking and TSE as well as decentralization of interlocking logic. These innovations can reduce the cabling required, increase the availability of diagnostic data, thus reducing maintenance and operational costs and can lead to power saving by utilizing local power sources. The most important impact of the SWOC is a significant reduction of CAPEX, OPEX and of total LCC for an installation utilizing SWOCs, instead of typical OCS.  This work focuses on estimating the LCC of a SWOC system and to compare it with a conventional OCS by developing an LCC model that covers both cases, as well as to use this model to examine when it is more profitable to implement a SWOC, instead of an OCS system. This is done by utilizing LCC analysis and combining a variety of methods in a parametric study. To that extend, a thorough analysis of a modern regional railway signalling system, as well as the basis for LCCA are being discussed. At the same time, both OC and SWOC systems are being described and factors affecting their cost discussed.  The methodology is comprised of the LCC modelling part as well as the collection of methods and techniques used to calculate the LCC of OC/SWOC systems and to estimate the costs of different sub-models and parameters of the process. For the modelling process, the station of Björbo was chosen, which operates under ERTMS-R system, but for the sake of the analysis it is assumed that the typical base system in place is an OCS and together with the existing track layout and equipment it is used as the basis of the analysis. Finally, the formed LCC model is being used in a parametric study to examine how the LCC is affected by using OC or SWOC as well as how LCC responds to changes in parameters such as number of OC/SWOC, traffic density and local power installation cost for the Björbo station. / I ett regionalt järnvägssignalsystem är utdelar de enheter som ansvarar för att kontrollera spårutrustning och fungerar de som gränsyta för spårutrustning med ställverksdatorn och tågtrafikledning systemet. Dock, tillhörande kablar (signalkablar ock kraftkablar), samt anläggningsinfrastruktur utgör en stor kapitalinvestering och de är en källa till märkbar kapitalkostnad och driftskostnader, särskilt på landsbygdsområden, där tillgänglighet och anslutning till elnätet och ställverket är problematisk. Dessutom, kablar och signalutrustning utsätts för stöld och sabotage i sådana områden. Detta kan öka den totala livscykelkostnaden ytterligare. Shift2rail forskningsprogram, som genomförs av EU och järnvägsintressenter, försöker att ta itu med problemet och modernisera utdelar konceptet genom projektet “TD2.10 Smart Radio Connected Wayside Object Controller”, där målet är att utveckla en Smart Spårutrustning Utdelar, så kallade SWOC. En SWOC har kapacitet för trådlös kommunikation mellan central ställverket och spårutrustning, samt decentralisering av satällverkslogiken. Dessa innovationer kan minska nödvändig kabeldragning, öka tillgängligheten av diagnostiska data, vilket minskar underhålls- och driftskostnader och kan leda till energibesparing genom att använda lokala kraftkällor. Den viktigaste effekten av SWOC är en betydande minskning av kapitalkostnader, driftskostnader och totala livscykelkostnaden för en installation som använder SWOC istället för typiska utdelningsystemet. Detta examensarbete fokuserar på att uppskatta LCC för ett SWOC-system och jämföra det med en konventionell utdelingsystem genom att utveckla en LCC-modell som täcker båda fallen, samt att använda denna modell för att undersöka när det är mer lönsamt att implementera en SWOC istället av ett typiskt utdelingsystem. Detta görs genom att använda LCC-analys och kombinera en mängd olika metoder i en parametrisk studie. För att göradetta genomförs en grundlig analys av ett modernt regionalt järnvägssignalsystem, samt grunden för livscykelanalys. Samtidigt beskrivs både ett typiskt utdelingssystem - och SWOC-system samt faktorer som påverkar deras kostnad deskuteras. Metoden består av LCC-modelleringsdelen samt insamling av metoder och tekniker som används för att beräkna LCC för OC / SWOC-system och för att uppskatta kostnaderna för olika delmodeller och parametrar för processen. För modelleringsprocessen valdes stationen i Björbo, som arbetar under ERTMS-R-systemet, men för analysens skull antas att det typiska bassystemet på plats är en typisk OCS och tillsammans med befintlig planritning ochkabelplan är används som grund för analys. Slutligen används den bildade LCC-modellen i en parametrisk studie för att undersöka hur LCC påverkas genom att använda OC eller SWOC samt hur LCC reagerar på förändringar i parametrar såsom antal OC / SWOC, trafiktäthet och lokala kraftinstallationskostnader för Björbo-stationen.
24

Evidenciação dos gastos ambientais do ciclo de vida do produto: uma aplicação do custeio baseado em atividades na indústria eletrônica / Discovering evidences of the environmental costs in the products lifecycle: an application of activity-based cost in the electronic industry

Rogério Ferraz Garcia de Andrade 21 February 2006 (has links)
As questões ambientais são variáveis estratégicas para as organizações do século XXI, pois pressionadas pela legislação ambiental com nível de exigência crescente - exigindo responsabilidades cada vez maiores para as fases finais do ciclo de vida dos produtos - e a sociedade não mais aceitando os custos dos impactos ambientais causados pela ação industrial - as externalidades - impulsionam as empresas a melhorar o desempenho ambiental de seus produtos e processos. É neste ambiente de mudanças que se torna necessário aos gestores e àqueles que tomam decisões conhecer e evidenciar os gastos ambientais em todo o ciclo de vida dos produtos comercializados. Por estes motivos apresentados é que este trabalho trata da evidenciação dos gastos ambientais no ciclo de vida do produto através da aplicação do método de custeio baseado em atividades e subsidiada pela realização de uma pesquisa-ação em uma empresa do setor eletrônico. A escolha do setor eletrônico se deve ao fato de que ao longo dos últimos 5 anos a legislação ambiental internacional de forma impositiva obrigou as companhias a alterar a composição de produtos - pelo banimento de diversas substâncias tóxicas, e a mudar processos - instituição obrigatória de índices de reciclagem por exemplo. Toda esta revolução foi acompanhada de perto pelo pesquisador, por isso a escolha da pesquisa-ação como metodologia, pois propiciou a modelagem de uma proposta de um método para a evidenciação dos gastos ambientais em todo o ciclo de vida do produto. / The environmental questions are strategical variables for the organizations in this century, therefore pressured by the increasing requirement level of the environmental legislation - which demands more responsibilities from the final phases of the products lifecycle - and the society, which is no longer accepting the costs of environmental impacts caused by the industrial actions - the externalities -, stimulating the companies to improve their products and processes environmental performance. This changing situation is the place where managers and other decision makers are asked to know and to evidence the environmental costs in all their traded products. It is because of these reasons that this work deals with the discovery of evidences of environmental costs in products lifecycle, by means of an application of the activity-based cost method, carried out according to the action research methodology in a company of the electronic segment. The choice of the electronic segment is due to the fact that in the last five years the international environmental legislation compelled these companies to change their products composition - by means of banishment of diverse toxic substances, and also to change their processes - by means of the institution of higher recycling rates, for example. All this revolution was closely followed by the researcher. This fact can explain the choice of action research methodology, which provided the proposal of a method for the evidence discovery of environment costs in the product lifecycle.
25

En miljö- och kostnadsjämförelse av insamlingssystem för källsortering närmare hushållen

Gyllenbreider, Emelie, Odencrants, Stina January 2017 (has links)
För att kunna uppnå de tuffare materialåtervinningsmålen som börjar gälla i Sverige år 2020 måste utsorteringen av bland annat plast-, papper- och metallförpackningar öka. Hushållsavfall beskrivs som en av de mest miljöpåverkande kategorin av avfall men samtidigt den kategori där det finns mest potential för förbättringar genom bättre hantering. Plockanalyser från 67 procent av Sveriges kommuner mellan åren 2013 och 2016 visar att ett svenskt villahushålls restavfall innehåller 34,5 procent förpackningar och returpapper som skulle kunna sorteras ut för materialåtervinning. Ett sätt att öka utsorteringen av producentansvarsmaterial från restavfallet och då kunna uppnå materialåtervinningsmålen är att kommuner erbjuder enklare samt ökad service i form av källsortering närmare hushållen. Tidigare studier har jämfört systemen optisk sortering och fyrfackskärl, som båda innebär källsortering närmare hushållen, med det vanligaste systemet i Sverige idag, tvåkärl, som inte innebär en ökad service genom kvalitativa metoder. Systemen har inte jämförts med kvantitativa metoder utifrån ekonomi eller miljö och inte heller med ett nytt koncept som heter Kvartersnära insamling. Den här rapporten har därför jämfört de fyra systemen utifrån aspekterna miljö och ekonomi med hjälp av verktygen livscykel- och livscykelkostnadsanalys som applicerades i ett område i Kristinehamns kommun för att på så sätt komma närmare verkligheten. Resultatet visar att systemet kvartersnära insamling har lägst miljöpåverkan i de undersökta miljöpåverkanskategorierna och därefter fyrfackskärl, optisk sortering och högst miljöpåverkan har systemet tvåkärl utifrån förutsättningarna och antagandena som har applicerats i studien. Livscykelanalysen visar att miljönyttan med materialåtervinningen överväger konsekvenserna av ökade transporter. Systemet med lägst livscykelkostnad är tvåkärl och sedan kvartersnära insamling, optisk sortering och dyrast livscykelkostnad har fyrfackskärl utifrån antaganden och de förutsättningar som använts i studien. En slutsats från rapporten är att det är viktigt att även undersöka andra aspekter förutom ekonomi och miljö vid val av insamlingssystem då resultatet till stor del beror på andra aspekter bland annat användarens uppfattning om systemet. / To achieve the stricter material recycling goals in Sweden in 2020 plastic-, metallic- and paper packages need to be better sorted from the household waste. Household waste might have the highest environmental impact compared with other sorts of waste but household waste has the highest potential to lower its impact. Waste pick-up analysis from 67 percent of Sweden's municipalities between 2013 and 2016 show that a Swedish household waste contains 34.5 percent packaging and recycled paper that could be sorted for recycling. The producers of that material have the responsibility to collect it but it does not work as well as planned because of different circumstances. One way to increase the recycling of the material from the household waste and then achieve the material recycling goals is that municipalities offer simpler and increased service in the form of source sorting closer to the households. Previous studies have compared the systems of optical sorting and multi compartment bin, which offer separation at sources closer to the households. Moreover, those systems have been compared with the most common system in Sweden today, two bins, which do not involve increased service. The systems have not been compared with quantitative methods based on economics or the environment, nor with a new concept called district collection. This report has compared the four systems. The aspects that have been compared are the environmental aspects and economical aspects by using the tools lifecycle assessment and lifecycle cost assessment. Moreover, the systems have been fictive studied in an area in the municipality of Kristinehamn, in order to get closer to reality. The results indicate that the collection system district collection had the lowest environmental impact followed by multi compartment bin and then optical sorting. Moreover, the system with two bins has the highest impact in the studied environmental impact categories according to the assumptions that have been applied in the study. The lifecycle assessment indicates that the benefits with material recycling is higher than the environmental impacts of increased transportation. The system with lowest lifecycle cost is the system with two bins and then the district collection. The system with highest lifecycle cost is the system optical sorting and the system with the second highest cost is multi compartment bin according to the assumptions that have been applied in the study. One conclusion from the study is that it is important to investigate more aspects than environmental impact and costs when to decide collection system. It is because the results depends on the other aspects as well like the users experience about the system.
26

Evidenciação dos gastos ambientais do ciclo de vida do produto: uma aplicação do custeio baseado em atividades na indústria eletrônica / Discovering evidences of the environmental costs in the products lifecycle: an application of activity-based cost in the electronic industry

Andrade, Rogério Ferraz Garcia de 21 February 2006 (has links)
As questões ambientais são variáveis estratégicas para as organizações do século XXI, pois pressionadas pela legislação ambiental com nível de exigência crescente - exigindo responsabilidades cada vez maiores para as fases finais do ciclo de vida dos produtos - e a sociedade não mais aceitando os custos dos impactos ambientais causados pela ação industrial - as externalidades - impulsionam as empresas a melhorar o desempenho ambiental de seus produtos e processos. É neste ambiente de mudanças que se torna necessário aos gestores e àqueles que tomam decisões conhecer e evidenciar os gastos ambientais em todo o ciclo de vida dos produtos comercializados. Por estes motivos apresentados é que este trabalho trata da evidenciação dos gastos ambientais no ciclo de vida do produto através da aplicação do método de custeio baseado em atividades e subsidiada pela realização de uma pesquisa-ação em uma empresa do setor eletrônico. A escolha do setor eletrônico se deve ao fato de que ao longo dos últimos 5 anos a legislação ambiental internacional de forma impositiva obrigou as companhias a alterar a composição de produtos - pelo banimento de diversas substâncias tóxicas, e a mudar processos - instituição obrigatória de índices de reciclagem por exemplo. Toda esta revolução foi acompanhada de perto pelo pesquisador, por isso a escolha da pesquisa-ação como metodologia, pois propiciou a modelagem de uma proposta de um método para a evidenciação dos gastos ambientais em todo o ciclo de vida do produto. / The environmental questions are strategical variables for the organizations in this century, therefore pressured by the increasing requirement level of the environmental legislation - which demands more responsibilities from the final phases of the products lifecycle - and the society, which is no longer accepting the costs of environmental impacts caused by the industrial actions - the externalities -, stimulating the companies to improve their products and processes environmental performance. This changing situation is the place where managers and other decision makers are asked to know and to evidence the environmental costs in all their traded products. It is because of these reasons that this work deals with the discovery of evidences of environmental costs in products lifecycle, by means of an application of the activity-based cost method, carried out according to the action research methodology in a company of the electronic segment. The choice of the electronic segment is due to the fact that in the last five years the international environmental legislation compelled these companies to change their products composition - by means of banishment of diverse toxic substances, and also to change their processes - by means of the institution of higher recycling rates, for example. All this revolution was closely followed by the researcher. This fact can explain the choice of action research methodology, which provided the proposal of a method for the evidence discovery of environment costs in the product lifecycle.
27

Miljö - och kostnadsanalys av UHPC som reparationsmaterial för bropelare / Sustainability of UHPC as a repair material for bridge piers

Huq, Saraj, Milosevic, Ivan January 2020 (has links)
Byggindustrin har i dagsläget en negativ klimatpåverkan och infrastrukturen likaså. Många länder har därför försökt undersöka möjligheten att hitta ett långsiktigt och hållbart alternativ till det konventionella reparationsmaterialet. Olika material undersöks, olika optimerade betongrecept testas för att förstå hur miljöpåverkan har minimeras för att förlänga livslängden hos betongkonstruktioner. Vid reparation av en bro är det viktigt att ta hänsyn till både kostnader och miljöpåverkan under hela dess livscykel. Kostnader som uppstår är investeringskostnader samt drift- och underhållskostnader. Miljöpåverkan från betongkonstruktioner i produkt skedet består av materialframställning, byggtransporter och produktion på byggarbetsplatserna. totala växthusgasutsläppet summeras och beräknas i kg CO2-ekv. Syftet med detta examensarbete är att studera den långsiktiga hållbarheten hos UHPC med hjälp av beräkningsmodeller såsom livscykelanalys och livscykelkostnadsanalys med avsikt att applicera reparationstekniken. Flera UHPC recept ställs mot det konventionella reparationsmaterialet detta för att kunna bedöma miljöpåverkan och kostnadseffektiviteten hos materialen. Dvs om det går det att minska klimatutsläppet och kostnaderna. De jämförda recepten är olika UHPC-recept samt traditionell betong. Recepten appliceras slutligen på en befintlig bropelare för att undersöka de olika receptens tillämpbarhet som reparationsmaterial ur ett hållbarhetsperspektiv. Det saknas tillräckligt med kunskap om UHPC:s långtidseffekter, speciellt om reparationsintervall. Med åtanke på materialets höga draghållfasthet och beständighet tillsammans med UHPC:s strukturella egenskaper har antaganden gjorts att materialet är reparationsfri under konstruktionens livslängd. Det vill säga att bropelaren som undersökts med UHPC i studien inte behövt repareras under sin livslängd. Resultatet från livscykelkostnadsanalysen visar att UHPC är dyrare i både kubikmeter (m3) och kvadratmeter (m2) med tanke på täckskiktets tjocklek än traditionell betong i materialpriset. Men med tanke på att UHPC är underhållsfritt har den en mindre livscykelkostnad. Resultatet från livscykelanalysen visar att UHPC blandningarna har större miljöpåverkan per kubikmeter. Då de olika täckskiktetstjocklek relateras till pelarens längd erhålls resultat där UHPC medför slankare konstruktioner och besparingar upp emot 50% mindre betongvolym (för den 6 m långa pelaren i fallstudien). Med UHPC som reparationsmaterial medför det till att bron inte behöver repareras under dess livslängd. Bropelaren som repareras med UHPC kommer därför ha en mindre miljöpåverkan än den traditionella betongen. Långsiktig hållbarhet och mindre totala växthusgasutsläpp (som är i riktlinje med EU:s och regeringens klimatkrav) erhålls för anläggningskonstruktioner med UHPC. / The construction industry has a negative climate impact and so does the infrastructure. Which is due to frequent repairs that are not sustainable. Many countries have therefore tried to explore the possibility of finding a long-term and sustainable alternative to conventional repair materials. Different materials are examined, different optimized concrete recipes are tested to understand how the environmental impact can be minimized and the service life of concrete structures extended. When repairing a bridge, it is important to take into account both costs and environmental impact throughout its life cycle. Costs that arise are investment costs as well as operating and maintenance costs. The environmental impact from concrete structures in the product phase consists of material production, construction transports and production at construction sites. The total greenhouse gas emissions are summed up and calculated in kg CO2 eq. The purpose of this thesis is to study the long-term sustainability of UHPC using calculation models such as life cycle analysis and life cycle cost analysis with the intention of applying the repair technique. Several UHPC prescriptions are set against the conventional repair material in order to be able to assess the environmental impact and cost-effectiveness of the materials. That is, if it is possible to reduce climate emissions and costs. The compared recipes are different UHPC recipes and traditional concrete. The recipes are finally applied to an existing bridge pillar to investigate the applicability of the various recipes as repair materials from a sustainability perspective. There is a lack of knowledge about the long-term effects of UHPC, especially about repair intervals. Given the high tensile strength and durability of the material together with the structural properties of the UHPC, it has been assumed that the material is repair-free for the life of the structure. That is, the bridge pillar examined with UHPC in the study did not need to be repaired during its lifetime. The results from the life cycle cost analysis show that UHPC is more expensive in both cubicmeters (m3) and square meters (m2) given the thickness of the cover layer than traditional concrete in the material price. However, given that UHPC is maintenance free, it has a lower lifecycle cost. The results from the life cycle analysis show that the UHPC mixtures have a greater environmental impact per cubic meter when the cover layer varies. As the thickness of the different cover layers is related to the length of the pillar, results are obtained where UHPC leads to slimmer constructions and savings of up to 50% less concrete volume (for the 6 m long pillar in the case study). With UHPC as repair material, this means that the bridge does not need to be repaired during its service life. The bridge pillar that is repaired with UHPC will therefore have a smaller environmental impact than the traditional concrete. Long-term sustainability and smaller total greenhouse gas emissions (which are in line with EU and government climate requirements) are obtained for plant constructions with UHPC.

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