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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.
231

Shop-floor society : work and social relations on the North Shore of Québec

Lapierre, Christine January 2005 (has links)
No description available.
232

Shop-floor society : work and social relations on the North Shore of Québec

Lapierre, Christine January 2005 (has links)
Iron Bay is a small community situated on the North Shore of the province of Quebec, where people work mainly in the resources and industrial sectors. This study examines the social relations of the workers of an iron pellet plant in that community, both at work and outside. The social organization of work, the relations between hierarchical orders at work and leisure activities are examined to produce an ethnographic account of the way of life of an affluent, if isolated, segment of the working class of Quebec.
233

Elucidating sweet corrosion scales

Joshi, Gaurav Ravindra January 2015 (has links)
The objective of this thesis is to improve understanding of the development of corrosion products (scales) that form on the inner walls of carbon steel pipelines in CO2-rich (sweet) oilfield environments. If well adherent to the carbon steel surface, such scales can significantly reduce the metal’s rate of corrosion. Typically, the open literature labels sweet corrosion scale as ferrous (II) carbonate (FeCO3) or siderite, although this may not always be the case. For example, Fe2(OH)2CO3 (chukanovite) and Fe3O4 (magnetite) are known to modify the protective character of a sweet corrosion product scale. Practical electrochemical methods for the assessment of substrate corrosion, and electron/photon-based characterisation techniques for investigating scale structure and composition, have revealed interesting aspects of the nature of sweet corrosion scale development on model high purity Fe and real-world pipeline steel surfaces. Concerning scale development on model Fe substrates immersed in CO2-saturated deionised water (buffered to pH = 6.8, T = 80°C, Ptotal = 1 bar), electrochemical data supplemented by grazing incidence x-ray diffraction (GIXRD) and scanning electron microscopy (SEM) show that a semi-protective mixed corrosion scale comprising siderite and chukanovite becomes a highly protective siderite scale with longer exposure time. The introduction of sodium chloride to the CO2-saturated solution (T = 80°C, pH = 6.8, Ptotal = 1 bar) impedes the rate of scale formation. Increasing [NaCl] from the start of experiment is suspected to limit the precipitation kinetics of sweet corrosion scale crystals, since chukanovite is no longer observed, and siderite formation is somewhat slowed as well. SEM imaging, using an electronic workfunction-sensitive detector (in lens), reveals nanoscale deposits on the corroded Fe surface in regions that are devoid of µm-scale crystals. With the Raman spectra from these regions considered, it is interpreted that the nanoscale deposits are likely amorphous iron carbonate, albeit oxidised to a significant extent. Moving to real-world carbon steel immersion in sweet solutions, a scale comprising predominantly chukanovite is observed (using GIXRD and SEM) on the 1% Ni weld zone (WZ) surface of a pipeline weld-joint, but not on adjacent, distinct regions (heat affected zones (HAZ) and base metal (BM)). This selective scaling is suggested to be due to some initial corrosion of the weld-joint, which generates sufficient [Fe2+(aq)], and a macro-galvanic effect across the weld, i.e. WZ is cathodic to HAZ and BM. Further, to gain mechanistic insight into compositional changes during sweet corrosion scale growth, an electrochemical cell for in situ GIXRD (named E-cell) has been developed and commissioned. Diffraction patterns acquired using synchrotron radiation, from a pipeline steel surface, reveal the formation and temporal evolution of a multicomponent corrosion scale. Accompanying electrochemical data suggest that the scale is quite protective.
234

A comparative study of power relationships of large State-Owned Enterprises (SOEs) and Private-Owned Enterprises (POEs) over small distributors considered from the distributors' perspective - the case of the iron and steel industry in China

Liu, Wei January 2016 (has links)
This thesis investigates manufacturer-distributor power relationship in the Chinese Iron and Steel Industry. The main objectives of this study are to identify, describe and investigate the power relationships in Chinese Iron and Steel Industry; to understand the concept of power from the perspective of distributors and their relationship with State-Owned Enterprises and Private-Owned Enterprises in this industry; and to explore the possibility of developing an extended research power-relationship framework by investigating the power construct and potentially related and relevant factors in the Chinese market that may impact predicted outcomes such as positive conflict resolution attitude and levels of conflict. Two quantitative pilot studies were conducted, consisting of 14 surveys with semi-structured questions each, which were instrumental in the design of an extended power relationship model by incorporating the factors such as the level of trust, frequency of communication and level of guanxi that drive positive conflict resolution attitude into the traditional power model that had not been combined in a single framework before. Subsequently, the main study was carried out comprising 148 questionnaires completed by distributor firm managers. These represent the views of 74 respondents, who responded for both state-owned enterprises and private-owned enterprises in the Chinese Iron and Steel Industry The sample size is 74 respondents including 14 respondents that were also respondents for the pilot studies. This study generated four main findings. 1) a State-Owned Enterprises tend to use more non-coercive power than Private-Owned Enterprises, and have a stronger negative effect than Private-Owned Enterprises; 2) although Private-Owned Enterprises were rated higher than State-Owned Enterprises in the level of trust, and have a stronger positive effect when explaining the observed relationship between the level of trust and positive conflict resolution attitude, the difference is really minimal; 3) Private-Owned Enterprises were rated higher than State-Owned Enterprises in the frequency of communication, and have a stronger positive effect than State-Owned Enterprises in the explanation of the relationship between frequency of communication and positive conflict resolution attitude. 4) Private-Owned Enterprises were rated higher than State-Owned Enterprises in the level of guanxi, and have stronger positive effect than State-Owned Enterprises in the explanation of the relationship between level of guanxi and positive conflict resolution attitude. These findings contribute to fill gaps in the literature with regard to power relationships in distribution channels. This thesis extends the current boundary of knowledge through the formulation of an extended framework that integrates conflict resolution constructs into a typical/traditional power model. This extended framework comprises new constructs such as level of trust, frequency of communication and level of guanxi and hypothesises their impact on conflict resolution attitude and level of conflict in the Chinese distribution channel. New knowledge is created by investigating differences regarding the use of power by SOEs and POEs considered from the distributor perspective in the Chinese context. Theoretical and managerial implications are discussed in detail.
235

Cost-effectiveness assessment of energy efficiency obligation schemes - implications for Swedish industries

Xylia, Maria January 2013 (has links)
This thesis is an investigation of whether an energy efficiency obligation scheme would be cost-effective for the Swedish industrial sector. The basic guidelines of the scheme were constructed based on the characteristics proposed in the Energy Efficiency Directive and the previously implemented schemes in other EU Member States. In order to measure the cost effectiveness of the scheme for the industries, a Cost Benefit Analysis was performed. The results of the study show that the participation of the industries in an energy efficiency obligation scheme seems to be cost effective, and the Benefit to Cost Ratios of the analysis where ranging in numbers higher than one, showing that the benefits outweigh the costs. The scheme is in general more cost effective when scenarios assuming high policy intensity for the whole economy of the country are used as input for the calculation of the BCRs, which are also affected positively when higher fuel prices scenarios are adopted. The obligation should be placed upon the distributors, since the prices of energy distribution are administratively regulated. There is opportunity of financial benefits for the Swedish industries from agreements of energy savings delivery to the distributors in order for them to fulfill their obligation. These benefits will support the cost recovery of the investments for the energy savings measures. The possibility of certificate trading in the context of the scheme is another option that can create opportunities for financial gains and stimulate further the energy market. Basing the costs inputs from other EU Member States offers an insight on how these costs could be formed in the case of Sweden, but they cannot be taken as a complete calculation of the scheme’s financial effects. As a result, this study does not offer a final conclusion on the cost-effectiveness of the scheme; it rather serves as a means of support of the final conclusion regarding the cost-effectiveness of energy efficiency obligation schemes for the Swedish industries.
236

Environmental Indicators : A Study of Eight Companies in Three Branches of Industry

Johansson, Stefan January 2004 (has links)
Swedish companies have invested a lot of time, effort and resources into becoming moreenvironmentally friendly. The primary focus of this on-going process has been to implementenvironmental management systems and to develop more environmentally friendlytechnologies. Measuring the effects of these actions has proven more difficult. Theintroduction of environmental indicators is emerging as a simple, yet effective way forcompanies to measure their environmental performance, increase the control of theirenvironmental activities and help the decision making process when developing new productsand processes. The aim of the project is to study to what extent eight Swedish companies in three differentbranches of industry use environmental indicators, if there are any similarities and differenceswithin and between branches and if any conclusions can be drawn. The companies chosen arethree companies within the pulp- and paper producing industry, three companies within theiron- and steel producing industry and two companies within the car manufacturing industry.The primary method of analysis is to study the environmental report from one factory of eachcompany, the environmental section of the financial report and/or the environmental report ofthe entire company or business group and environmental information on each company’s website. No interviews were conducted with any of the companies, since it was deemed that therewas not enough time if they were to be meaningful. Before the evaluation, the concept of environmental indicators needs further examination. Theindicators are comparative, comparing an environmental quantity to a financial one. Examplesof common indicators are energy use per quantity of produced product or emissions of CO2-equivalents per tonne of produced product. Since the denominator is the same, companieswith significantly different sizes of production can easily be compared to each other. Today itis hard if even possible to compare companies within the same branch to each other and evenharder to compare ones in different branches to each other or to branch indexes. The lack ofcommon guidelines for measuring, processing and presenting the results of environmentalperformance data is the biggest problem when using environmental indicators today. The environmental indicators can be used in a number of different roles. Today they are usedto measure and compare the environmental performance of a company as well as tools forcommunication to various stakeholders. If the companies continue to develop the indicators,they can be used pro-actively in the decision making process as well as to highlight problemareas and to track the progress towards goals set by the company. Some of the companies inthis report are already using indicators in one or more of the advanced roles. All the companies were evaluated in two different ways, qualitatively and quantitatively atthree levels of reporting. The three levels were the environmental report from a single factory,the environmental report for the entire company/business group and the environmentalinformation on the Internet from each company. The qualitative evaluation analysed how the companies used environmental indicators, if thecompanies used them explicitly, if they used them to track goals and if there were differencesbetween the different levels of reporting. The analysis showed that only a few companies usedenvironmental indicators at the single factory level, but that all companies used them in thebusiness group reports and on the Internet. There was also a much higher degree of coherencybetween the companies financial reporting than there was in their environmental one. Thequalitative evaluation also showed that the pulp- and paper companies used the mostenvironmental indicators, the iron- and steel companies used them most effectively and thatthe car companies used them to their fullest extent. The quantitative evaluation analysed each company by itself to examine how each individualcompany used the environmental indicators. The differences between the use of indicators atthe different levels of reporting also became more evident. The pulp- and paper companieswere the most consistent while the iron- and steel companies had the biggest differences withthe car companies somewhere in between. The analysis also showed that companies that werepart of bigger business groups had bigger differences, especially if they were not part of themother company. There are two major conclusions that can be drawn from the report. The first one is thatcompanies use environmental indicators to measure and present their environmentalperformance because they see them as effective tools. The second one is that commonguidelines are necessary to develop the indicators further. The first conclusion can be drawn from the fact that all the companies use environmentalindicators as a tool for reporting their environmental performance in their primary channels ofinformation, the business group reports and on the Internet The second conclusion can be drawn from the fact that even though the companies werechosen because they produced different products, they turned out to have very similar types ofemissions but very different environmental indicators. Since all the companies are verysincere in their efforts to limit their impact, on the environment and the fact that they have allchosen environmental indicators to measure their impact the need for coherency is great forfurther development. It is doubtful that the companies themselves can develop the indicatorson their own which means that the authorities and possibly the branch organisations have towork together to develop common guidelines. The biggest challenges are to decide on thecommon rules of reporting and to put financial values on the environment. If these problemscan be resolved, environmental indicators can be used to their fullest potential in the future. / www.ima,kth.se
237

Towards a fossil free steel sector : Conditions for technology transfer of hydrogenbased iron and steel in Europe / Mot en fossilfri stålsektor : Förutsättningar för tekniköverföring av vätgasbaserat järn och stål i Europa

Öhman, Amanda January 2019 (has links)
In order to meet the targets of the Paris Agreement, there is a need to significantly reduce emissions from energy-intensive industries, iron and steel included. One promising technology with the potential to reduce the emissions related to iron and steelmaking to basically none is direct reduction with fossil free hydrogen, which requires large amounts of fossil free electricity. This master thesis explores the conditions for this technology in a European context with an energy perspective as the main focus. Three primary steel producing countries in Europe are chosen as focus countries; Germany, France and Italy. The findings of the study conclude that neither of the focus countries is an optimal sociotechnical fit for hydrogen-based direct reduction for iron and steel production at present. France is the country with the best conditions from a solely energy perspective but lacks some important factors for an enabling environment for technology transfer. Germany on the other hand have the most promising characteristics for an enabling environment but still face large challenges when it comes to power sector decarbonisation. In order to overcome the barriers and create an enabling environment it is key that energy and industry transitions are aligned, that a policy framework that supports these transitions is in place and that key actors representing all aspects of the transition cooperate; from industry to research, academia, policymakers and others. The findings also show that the current locations of the primary steel plants are in many cases not where the most favourable conditions for renewable power generation are and given the renewable capacity and transmission limitations of today, merely switching to a hydrogenbased process is not likely viable. A future configuration could be decentralised value chains where the different processes are located where there are optimal conditions e.g. that either hydrogen or sponge iron is produced where there are favourable power conditions and then transported to steel plants for the remaining processes in the value chain. / För att nå målen uppsatta i Parisavtalet behöver energiintensiva industrier kraftigt minska sina utsläpp, däribland järn- och stålindustrin. Direktreduktion med fossilfri vätgas är en teknologi med potential att minska utsläppen från järn och ståltillverkning till praktiskt taget noll men kräver stora mängder fossilfri el. Detta examensarbete undersöker de energimässiga förutsättningarna för denna teknik i en europeisk kontext. Tre länder som producerar primärstål är utvalda som fokusländer i studien; Tyskland, Frankrike och Italien. Resultaten av studien visar att inget av de utvalda länderna i dagsläget har optimala sociotekniska förutsättningar för tekniken. Frankrike är det land med de bästa energimässiga förutsättningarna men saknar några viktiga faktorer för att vara en möjliggörande socioteknisk miljö. Tyskland å andra sidan har de mest lovande förutsättningarna för en lämplig socioteknisk miljö men står inför utmaningar när det kommer till energisystemet och tillgången på fossilfri el. För att skapa förutsättningar för denna teknik är det viktigt med koordinerade omställningar i energisektorn och industrin, policys som möjliggör dessa omställningar samt ett väl fungerande samarbete mellan industrin, akademin, beslutsfattare och andra viktiga aktörer. Studien visar också att de platser där nuvarande stålverk för primärstål finns inte har de bästa förutsättningar för förnybar elproduktion och att en vätgasbaserad process inte är optimal, baserat på den förnybara kapaciteten och de transmissionsbegränsningar som finns idag i elsystemet. Det finns istället möjlighet till decentraliserade värdekedjor, där varje process placeras där de mest lämpliga förhållandena finns. Detta kan exempelvis innebära att vätgas eller järnsvamp produceras där tillgången till fossilfri el är god, för att sedan transporteras till stålverken för de resterande processtegen.
238

Improved Energy Efficiency and Fuel Substitution in the Iron and Steel Industry

Johansson, Maria January 2014 (has links)
IPCC reported in its climate change report 2013 that the atmospheric concentrations of the greenhouse gases (GHG) carbon dioxide (CO2), methane, and nitrous oxide now have reached the highest levels in the past 800,000 years. CO2 concentration has increased by 40% since pre-industrial times and the primary source is fossil fuel combustion. It is vital to reduce anthropogenic emissions of GHGs in order to combat climate change. Industry accounts for 20% of global anthropogenic CO2 emissions and the iron and steel industry accounts for 30% of industrial emissions. The iron and steel industry is at date highly dependent on fossil fuels and electricity. Energy efficiency measures and substitution of fossil fuels with renewable energy would make an important contribution to the efforts to reduce emissions of GHGs. This thesis studies energy efficiency measures and fuel substitution in the iron and steel industry and focuses on recovery and utilisation of excess energy and substitution of fossil fuels with biomass. Energy systems analysis has been used to investigate how changes in the iron and steel industry’s energy system would affect the steel plant’s economy and global CO2 emissions. The thesis also studies energy management practices in the Swedish iron and steel industry with the focus on how energy managers think about why energy efficiency measures are implemented or why they are not implemented. In-depth interviews with energy managers at eleven Swedish steel plants were conducted to analyse energy management practices. In order to show some of the large untapped heat flows in industry, excess heat recovery potential in the industrial sector in Gävleborg County in Sweden was analysed. Under the assumptions made in this thesis, the recovery output would be more than three times higher if the excess heat is used in a district heating system than if electricity is generated. An economic evaluation was performed for three electricity generation technologies for the conversion of low-temperature industrial excess heat. The results show that electricity generation with organic Rankine cycles and phase change material engines could be profitable, but that thermoelectric generation of electricity from low-temperature industrial excess heat would not be profitable at the present stage of technology development. With regard to fossil fuels substituted with biomass, there are opportunities to substitute fossil coal with charcoal in the blast furnace and to substitute liquefied petroleum gas (LPG) with bio-syngas or bio synthetic natural gas (bio-SNG) as fuel in the steel industry’s reheating furnaces. However, in the energy market scenarios studied, substituting LPG with bio-SNG as fuel in reheating furnaces at the studied scrap-based steel plant would not be profitable without economic policy support. The development of the energy market is shown to play a vital role for the outcome of how different measures would affect global CO2 emissions. Results from the interviews show that Swedish steel companies regard improved energy efficiency as important. However, the majority of the interviewed energy managers only worked part-time with energy issues and they experienced that lack of time often was a barrier for successful energy management. More efforts could also be put into engaging and educating employees in order to introduce a common practice of improving energy efficiency at the company. / Halterna av växthusgaserna koldioxid (CO2), metan och kväveoxider har under de senaste 800 000 åren aldrig varit högre i atmosfären än vad de är idag. Detta resultat redovisades i IPCCs klimatrapport år 2013. CO2-koncentrationen har ökat med 40 % sedan förindustriell tid och denna ökning beror till största delen på förbränning av fossila bränslen. Ökade koncentrationer av växthusgaser leder till högre global medeltemperatur vilket i sin tur resulterar i klimatförändringar.  För att bromsa klimatförändringarna är det viktigt att vi arbetar för att minska utsläppen av växthusgaser. Industrin står för 20 % av de globala utsläppen av CO2 och järn- och stålindustrin står för 30 % av industrins utsläpp. Järn- och stålindustrin är i dag till stor del beroende av fossila bränslen och el för sin energiförsörjning. Energieffektiviseringsåtgärder och byte av fossila bränslen mot förnybar energi i järn- och stålindustrin skulle kunna bidra till minskade utsläpp av växthusgaser. Denna avhandling studerar åtgärder för effektivare energianvändning och möjligheter för bränslebyte i järn- och stålindustrin. Avhandlingen fokuserar på återvinning och utnyttjande av överskottsenergier och ersättning av fossila bränslen med biomassa. Energisystemanalys har använts för att undersöka hur förändringar i järn- och stålindustrins energisystem skulle påverka ekonomin och de globala utsläppen av CO2. Avhandlingen studerar också betydelsen av energiledning och nätverkande för att uppnå en effektivare energianvändning. Fokus har här varit på att studera hur energiansvariga resonerar kring varför energieffektiviseringsåtgärder genomförs eller varför de inte genomförs. Djupintervjuer med energiansvariga vid elva svenska stålverk genomfördes för att analysera denna fråga. För att ge ett exempel på den stora outnyttjade potentialen av överskottsvärme från industrin analyserades potentialen i Gävleborgs län. Möjligheterna att använda överskottsvärmen som fjärrvärme eller för att producera el analyserades. Här visar resultaten att fjärrvärmeproduktionen skulle bli mer än tre gånger så stor som elproduktionen. En ekonomisk utvärdering gjordes där tre tekniker för produktion av el från lågtempererad industriell överskottsvärme jämfördes. Resultaten visar att elproduktion med organisk Rankine-cykel eller en så kallad fasändringsmaterialmotor kan vara lönsam, men att termoelektrisk elproduktion inte är lönsam med dagens teknik och prisnivåer. Det är möjligt att ersätta en del av det fossila kolet i masugnen med träkol och på detta sätt introducera förnybar energi i stålindustrin. Man kan också ersätta gasol som används som bränsle i stålindustrins värmningsugnar med syntesgas eller syntetisk naturgas (SNG) som produceras genom förgasning av biomassa. Under de antaganden som gjorts i avhandlingen skulle det dock inte vara lönsamt för det skrotbaserade stålverk som studerats att ersätta gasolen med bio-SNG. För att uppnå lönsamhet behövs i detta fall ekonomiska styrmedel. Hur olika åtgärder påverkar de globala utsläppen av CO2 beror till stor del på hur framtidens energimarknad ser ut. Elproduktion från industriell överskottsvärme skulle minska de globala CO2-utsläppen i alla scenarier som studerats, men för de andra åtgärderna varierar resultaten beroende på vilka antaganden som gjorts. Resultaten från intervjustudien visar att svensk stålindustri anser att energifrågan är viktig, men det finns fortfarande mycket att göra för att effektivisera energianvändningen i denna sektor. Flera av de intervjuade arbetade bara deltid med energifrågor och de upplevde att tidsbrist hindrade dem från ett effektivt energiledningsarbete. En rekommendation till företagen är därför att anställa en energiansvarig på heltid och/eller fler personer som kan arbeta med energifrågor. Det bör också läggas mer resurser på att engagera och utbilda anställda för att på så sätt introducera en företagskultur som främjar effektiv energianvändning.
239

Innovative energy technologies in energy-economy models

Schumacher, Katja 08 August 2007 (has links)
Die Einführung neuartiger Energietechnologien wird allgemein als der Schlüssel zur Senkung klimaschädlicher Treibhausgase angesehen. Allerdings ist die Abbildung derartiger Technologien in numerischen Modellen zur Simulation und ökonomischen Analyse von energie- und klimaschutzpolitischen Maßnahmen vielfach noch rudimentär. Die Dissertation entwickelt neue Ansätze zur Einbindung von technologischen Innovationen in energie-ökonomische allgemeine Gleichgewichtsmodelle, mit dem Ziel den Energiesektor realitätsnäher abzubilden. Die Dissertation adressiert einige der Hauptkritikpunkte an allgemeinen Gleichgewichtsmodellen zur Analyse von Energie- und Klimapolitik: Die fehlende sektorale und technologische Disaggregation, die beschränkte Darstellung von technologischem Fortschritt, und das Fehlen von einem weiten Spektrum an Treibhausgasminderungsoptionen. Die Dissertation widmet sich zwei Hauptfragen: (1) Wie können technologische Innovationen in allgemeine Gleichgewichtsmodelle eingebettet werden? (2) Welche zusätzlichen und politikrelevanten Informationen lassen sich durch diese methodischen Erweiterungen gewinnen? Die Verwendung eines sogenannten Hybrid-Ansatzes, in dem neuartige Technologien für Stromerzeugung und Eisen- und Stahlherstellung in ein dynamisch multi-sektorales CGE Modell eingebettet werden, zeigt, dass technologiespezifische Effekte von großer Bedeutung sind für die ökonomische Analyse von Klimaschutzmaßnahmen, insbesondere die Effekte hinsichtlich von Technologiewechsel und dadurch bedingten Änderungen der Input- und Emissionsstrukturen. Darüber hinaus zeigt die Dissertation, dass Lerneffekte auf verschiedenen Stufen der Produktionskette abgebildet werden müssen: Für regenerative Energien, zum Beispiel, nicht nur bei der Anwendung von Stromerzeugungsanlagen, sondern ebenso auf der vorgelagerten Produktionsstufe bei der Herstellung dieser Anlagen. Die differenzierte Abbildung von Lerneffekten in Exportsektoren, wie zum Beispiel Windanlagen, verändert die Wirtschaftlichkeit und die Wettbewerbsfähigkeit und hat wichtige Implikationen für die ökonomische Analyse von Klimapolitik. / Energy technologies and innovation are considered to play a crucial role in climate change mitigation. Yet, the representation of technologies in energy-economy models, which are used extensively to analyze the economic, energy and environmental impacts of alternative energy and climate policies, is rather limited. This dissertation presents advanced techniques of including technological innovations in energy-economy computable general equilibrium (CGE) models. New methods are explored and applied for improving the realism of energy production and consumption in such top-down models. The dissertation addresses some of the main criticism of general equilibrium models in the field of energy and climate policy analysis: The lack of detailed sectoral and technical disaggregation, the restricted view on innovation and technological change, and the lack of extended greenhouse gas mitigation options. The dissertation reflects on the questions of (1) how to introduce innovation and technological change in a computable general equilibrium model as well as (2) what additional and policy relevant information is gained from using these methodologies. Employing a new hybrid approach of incorporating technology-specific information for electricity generation and iron and steel production in a dynamic multi-sector computable equilibrium model it can be concluded that technology-specific effects are crucial for the economic assessment of climate policy, in particular the effects relating to process shifts and fuel input structure. Additionally, the dissertation shows that learning-by-doing in renewable energy takes place in the renewable electricity sector but is equally important in upstream sectors that produce technologies, i.e. machinery and equipment, for renewable electricity generation. The differentiation of learning effects in export sectors, such as renewable energy technologies, matters for the economic assessment of climate policies because of effects on international competitiveness and economic output.
240

Influence of cross-frame detailing on curved and skewed steel I-girder bridges

Ozgur, Cagri 25 August 2011 (has links)
Curved and skewed I-girder bridges exhibit torsional displacements of the individual girders and of the overall bridge cross-section under dead loads. As a result, the girder webs can be plumb in only one configuration. If the structure is built such that the webs are plumb in the ideal no-load position, they generally cannot be plumb under the action of the structure's steel or total dead load; hence, twisting of the girders is unavoidable under dead loads. The deflected geometry resulting from these torsional displacements can impact the fit-up of the members, the erection requirements (crane positions and capacities, the number of temporary supports, tie down requirements, etc.), the bearing cost and type, and the overall strength of the structure. Furthermore, significant layover may be visually objectionable, particularly at piers and abutments. If the torsional deflections are large enough, then the cross-frames are typically detailed to compensate for them, either partially or fully. As specified in Article C6.7.2 of the AASHTO LRFD Specifications, different types of cross-frame detailing methods are used to achieve theoretically plumb webs under the no-load, steel dead load, or total dead load conditions. Each of the cross-frame detailing methods has ramifications on the behavior and constructability of a bridge. Currently, there is much confusion and divergence of opinion in the bridge industry regarding the stage at which steel I girder webs should be ideally plumb and the consequences of out-of-plumbness at other stages. Furthermore, concerns are often raised about potential fit-up problems during steel erection as well as the control of the final deck geometry (e.g., cross-slopes and joint alignment). These influences and ramifications of cross-frame detailing need to be investigated and explained so that resulting field problems leading to needless construction delays and legal claims can be avoided. This dissertation addresses the influence of cross-frame detailing on curved and/or skewed steel I girder bridges during steel erection and concrete deck placement by conducting comprehensive analytical studies. Procedures to determine the lack-of-fit forces due to dead load fit (DLF) detailing are developed to assess the impact of different types of cross-frame detailing. The studies include benchmarking of refined analytical models against selected full scale experimental tests and field measurements. These analytical models are then utilized to study a variety of practical combinations and permutations of bridge parameters pertaining to horizontal curvature and skew effects. This research develops and clarifies procedures and provides new knowledge with respect to the impact of cross-frame detailing methods on: 1) constructed bridge geometries, 2) cross-frame forces, 3) girder stresses, 4) system strengths, 5) potential uplift at bearings, and 6) fit-up during erection. These developments provide the basis for the development of refined guidelines for: 1) practices to alleviate fit-up difficulties during erection, 2) selection of cross-frame detailing methods as a function of I-girder bridge geometry characteristics, and 3) procedures to calculate the locked-in forces due to DLF cross-frame detailing.

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