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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.
71

Field Observation of Installation and Performance of Repair Materials

Susinskas, Larisa Diana 22 August 2016 (has links)
No description available.
72

SPECIFICATION RECOMMENDATION FOR USE OF HIGH PERFORMANCE REPAIR MATERIAL

Woods, Jennifer January 2016 (has links)
No description available.
73

A Guideline for Establishing Local Energy-Efficiency Programs in Virginia

St.Jean, David Bryan 24 January 2011 (has links)
From a big picture perspective, investing in energy efficiency in the existing stock of residential buildings in the United States brings unquestioned economic, employment and environmental benefits. The aggregation of energy and dollar savings from millions of small improvements in efficiency adds up to enormous regional and national savings. By employing cost-effective investments in building efficiency, we could reduce the cumulative energy use of America's housing stock by twenty-eight percent, save Americans $41 billion annually, abate 360 megatons of CO-2 (Choi Granade, et.al., 2009), and meet fifty percent or more of the expected electric load growth by 2025 (EPA, 2008). In Virginia alone investing in the efficiency of our existing stock of buildings could save the commonwealth's residents $2.2 billion annually by 2025 (ACEEE, 2008). But from the perspective of the individual property owner the potential benefits of investing in energy efficiency, although just as real, are either less obvious or have impediments to their attainment. Understanding and overcoming these micro-impediments to energy investing is essential to realizing the macro-benefits of energy efficiency. Consequently, any successful local energy program must tailor its efforts to address the barriers to investing in efficiency at the level of the individual consumer. This thesis, through an analysis of existing and emerging residential energy programs, along with a review of the behavioral and economic literature on the subject, aims to point out the micro-impediments to achieving macro-reductions in energy use. Becoming familiar with these obstructions on the level of the individual consumer is the first necessary step in producing model guidelines for a successful whole house local energy efficiency program. Although the basic tenets of these guidelines could be used as the basis for any locally organized energy program in the U.S., they are specifically tailored in this thesis for the Commonwealth of Virginia. / Master of Urban and Regional Planning
74

Interrelated dataset of rebound numbers, ultrasonic pulse velocities and compressive strengths of drilled concrete cores from an existing structure and new fabricated concrete cubes

Gebauer, Daniel, Beltrán Gutiérrez, Raúl Enrique, Marx, Steffen, Butler, Marko, Grahl, Konrad, Thiel, Thomas, Maack, Stefan, Küttenbaum, Stefan, Pirskawetz, Stephan, Breit, Wolfgang, Schickert, Martin, Krüger, Marco 10 January 2025 (has links)
Two test series were examined using nondestructive measuring methods by six independent laboratories before determining their compressive strength. The nondestructive test methods used were the rebound hammer and ultrasonic pulse velocity measurement. Two types of geometries were investigated: drilled cores and cubes. The measurement procedure for each of these datasets is conditioned to the geometry and is therefore different. The first series consists of 20 drilled cores (approximately diameter/height = 10 cm/20 cm) from the 55-year-old Lahntal Viaduct near Limburg, Germany. After preparation in the first laboratory, the lateral surface of the drilled cores was tested with the rebound hammer using a given pattern. Every laboratory tested every drilled core at different locations. Ultrasonic measurements in transmission were performed repeatedly at predefined points on the flat surfaces of the specimen. The second series consisted of 25 newly manufactured concrete cubes of a mix with a target concrete strength class of C30/37. The edge length was 15 cm. Each laboratory received five specimens of this test series. Thus, contrary to the first series, each specimen was tested by only one laboratory. Two side faces of each cube were tested with the rebound hammer. In addition, ultrasonic measurements were performed by one laboratory. The time of flight was measured between the tested side faces of the rebound hammer at different positions. For both series, rebound hammers were used to determine the R-value as well as the Q-value. The rebound hammer models within the laboratories were always the same, while they differed between the laboratories. The ultrasonic measurements took place with different measurement systems and couplants. Finally, both specimen series were tested destructively for compressive strength. The dataset contains the raw data summarized in tabular form. In addition, relevant calculated data are included in some cases. For the ultrasonic measurements, the time of flight has already been converted into the ultrasonic velocity. Besides, in addition to the raw data of the compressive strength test (force, weight, and geometry values), the calculated compressive strengths and densities are also provided.
75

Vytvoření předpokladů pro hodnocení vlastností vysokopevnostních betonů s využitím nedestruktivních metod zkoušení / Creating conditions for evaluation of high-strength concrete characteristics using non-destructive testing methods

Procházka, David Unknown Date (has links)
High-strength concrete (HSC) belongs in the recent years to frequently used types of concrete. It allows realization of static challenging structures and also shows due to its dense structure greater durability especially against aggressive media. Currently HSC construction realization abroad is not exceptional. It’s using in the Czech Republic is still limited. When realized, then in a small scale in civil engineering works. The realization of high-strength concrete structures is closely related with the concrete construction quality verification. Good efficiency of the quality control methods can provide non-destructive testing methods (NDT), especially when investigating strength of concrete built in structure. A lack on relevant data for non-destructive testing of HSC in technical and normative rules is to be considered as a significant deficiency. Evident for HSC generally is the lack in literature on deeper analysis of the factors affecting their non-destructive testing, as well a meaningful methodology or practically usable calibration relationships. HSC differs from ordinary concrete not only by used components, but also by more compact structure with different strength – elastic characteristics. Considering these differences, HSC strength prediction can not be performed by using calibration relationships developed for ordinary concrete. Moreover, the question is to what extent the current knowledge of the NDT results influencing factors can be considered as valid. The paper presents findings on the effects of the key factors affecting the measurement results of Schmidt hardness method and ultrasonic pulse method, including recommendations for the practical application of these methods. The problematic of static vs. dynamic modulus of elasticity was also solved. Calibration equations for predicting the compressive strength of HSC from the non-destructive testing parameter were elaborated, showing high cohesion among variables and practically usability.
76

Estimation of the characteristic in-situ compressive strength class of concrete structures - A case study of the Skuru bridge / Bedöming av den karaktäristiska tryckhållfasthetsklassen för betong konstruktioner - en fallstudie av Skuru bron

Ahmadiyan, Sara, Mehari, Daniel January 2021 (has links)
It is inevitable that Structures become older and their intended use changes or the structuralcodes regulations change. In some regions the damage from seismic activities is a possibility.It becomes, therefore crucial to assess the structural capacity of such structures. The purposeof this study is to assess the different methods used for testing and estimating thecharacteristic in-situ compressive strength which is the most vital parameter required instructural assessment. The focus of the study is for existing structures where there is no prior knowledge about theconcrete strength. This study first investigates and evaluates the merits and demerits of thesemethods for investigation of the condition of in-situ compressive strength of concrete inexisting structures. A case study of the Skuru bridge that was built in 1914 was utilized forthis study. The study is based on information of the construction data and some results fromprior investigation performed by the company COWI. Afterwards, non-destructive tests werecarried out with the UPV and Rebound hammer to assess the quality of the concrete. In addition, the study assesses the use of different interpretation methods with regards toreliability and practical application. The results were interpreted in accordance to theEuropean codes, Swedish codes and other interpretation methods. The difference of theresults from the different interpretation methods are compared and evaluated for reliabilityand efficiency. The test results confirmed that the concrete consisted of the same strength class. However,the results from the different interpretation methods are dissimilar. The reason for obtainingdifferent results is because the methods depend on different methodologies. The studyshowed that some methods can sometimes overestimate the results and become unsafe forstructural assessment. On the contrary, the other methods can yield lower but safer estimates. Moreover, the use of small number of cores is evaluated for various methods. The reasons arebecause in practice, the preference is to avoid large number of cores. As a result, it isrecommended to apply care and proper judgment in selection of the methods andinterpretation of the results. It is also recommended to consider the methods with respect tothe aim of the investigation, their limitations and assumptions. / Samtida befintliga konstruktioner blir äldre och de dimensionerade lasterna ökar med tiden.Ifatt med detta ändras även kraven för större laster. Därför bör regelbundna inspektioner ochförbättringar genomföras. I vissa områden kan det även förekomma seismiska rörelser som isin tur förorsakar skador på strukturer. Av bland annat dessa anledningar är det därför viktigtatt bedöma bärförmågan för befintliga konstruktioner. Syftet med arbetet är att granska demetoder och tillvägagångssätt som finns för att kunna bedöma den karaktäristiskatryckhållfastheten för betong i befintliga konstruktioner. Tryckhållfastheten är den styrandeparametern för materialet under tillståndsbedömningar. Huvudfokuset med arbetet är att bedöma den karaktäristiska tryckhållfastheten för befintligakonstruktioner som saknar information om nuvarande tryckhållfasthet. Till en början utfördesen noggrann litteraturstudie för alla applicerbara metoder. Därefter gjordes en undersökningoch bedömning av för- och nackdelar med vardera metod. Syftet med dessa metoder är attkunna mäta den nuvarande tryckhållfastheten för befintliga konstruktioner. Efter en ingående litteraturstudie, valdes de icke-destruktiva metoderna Ultrasonic pulsevelocity och Schmidt Hammer. Dessa metoder applicerades senare på Skuru bron i syfte attutföra icke-destruktiva tester för att bedöma betongens kvalitet. Tidigarekonstruktionshandlingar samt provtagningsrapporter från Skurubron som byggdes år 1914,har legat till grund för detta arbete. Företaget COWI är ansvariga för Skurubron projektet ochhar tillhandahållit all information om bron. Vidare, redovisar detta arbete olika beräkningssätt för samtliga metoder utifrån olikastandarder och tolkningsmetoder. För varje tolkningsmetod har evalueringar och analyserutförts med avseende på tillförlitlighet och praktisk tillämpning. De redovisadeberäkningssätten har använts för att räkna fram resultat från destruktiva och icke-destruktivatester. Resultaten tolkades i enlighet med europeiska koder, svenska koder och andratolkningsmetoder. Skillnaden mellan resultaten från samtliga tolkningsmetoder jämförs ochutvärderas med hänsyn till tillförlitlighet och effektivitet. Testresultaten från UPV och Schmidt Hammer bekräftade att betongen består av sammatryckhållfasthetsklass. Resultaten från de olika tolkningsmetoderna var dock olika.Anledningen till att det blev olika resultat beror på att varje tolkningsmetod utgörs av sinaegna metodiska procedurer. Resultaten visade även att vissa standarder kan övervärderaresultaten vilket kan resultera i fel bedömning av den karaktäristiska tryckhållfastheten. Åandra sidan, resulterade vissa tolkningsmetoder i lägre men säkrare uppskattning avtryckhållfastheten. Utöver detta, utfördes det beräkningar på de destruktiva testerna utifrån olikatolkningsmetoder. Beräkningarna baserades dels på att räkna på ett mindre antal kärnor.Skälet till detta är att man i praktiken vill undvika att borra ett stort antal kärnor. Resultatenvisade att korrekt bedömning och försiktighet vid val av metod och tolkningsmetod behöverimplementeras. Det rekommenderas även att överväga metoderna med hänsyn tillutredningens ändamål, dess begränsningar och antaganden.
77

Monitoração dinâmica na cravação de estacas: aplicabilidade da equação de Energy Approach e estimativas das tensões de compressão. / Dynamic monitoring in pile driving: applicability of the Energy Approach equation and compression stresses estimation.

Querelli, André Esposito 09 May 2019 (has links)
Fundações constituídas de estacas pré-moldadas cravadas têm, na questão dos controles executivos, significativas vantagens em relação às estacas moldadas in loco: desde a simplicidade executiva dos diagramas de cravação até a sofisticação teórica dos ensaios de carregamento dinâmico, há sempre a possibilidade de expeditas verificações de comportamento da cravação, de homogeneidade de estaqueamento e até estimativas da capacidade de carga. No entanto, assim como o grande número de dispositivos de controle para esse tipo de estaca representa uma vantagem, a diversidade de formas existentes de interpretá-los representa, igualmente, uma desvantagem. Em face disso, a presente pesquisa compilou 881 registros de ensaios de carregamento dinâmico (708 em estacas de concreto e 173 em estacas de aço) e os comparou com as estimativas de resistência da Equação de Energy Approach. A aplicabilidade da equação foi testada aos dois materiais de estaca, principalmente quando se estudaram variações do parâmetro Ksp em relação às diversas grandezas envolvidas na cravação, seus extremos empíricos e uma proposta de calibração à fórmula dinâmica por meio desse parâmetro chave. O estudo dos ensaios dinâmicos também levou à proposição de uma equação para se estimar a energia efetivamente transferida à estaca no golpe do martelo por meio da nega e do repique elástico. O presente estudo também dedicou uma seção à questão das tensões dinâmicas de compressão na cravação, avaliando estimativas de tensões por meio da Equação de Gambini e propondo duas versões alternativas ao método: uma primeira, simplificada e uma de cunho prático, com objetivo de possibilitar rápidas estimativas das tensões de compressão quando ainda em campo. / Driven precast piled foundations have significant advantages in respect of quality control over cast-in-place piles - from the executive simplicity of the blow count diagrams to the theoretical sophistication of dynamic load tests - there is always the possibility of fast and practical driving behavior check, homogeneity and even load capacities estimation. However, as the large number of available quality controls represents an advantage, that diversity can equally represent a disadvantage in respect to interpretation and methodology. Therefore, the present research compiled 881 records of dynamic load tests (708 on concrete piles and 173 on steel piles) and compared them with the resistance estimation with the Energy Approach Equation. The applicability of the equation was tested for both materials, especially when studying its main parameter (Ksp) variation related to several variables involved in pile driving, its empirical extremes and a calibration to the dynamic formula by means of Ksp. The study of the dynamic tests also led to the proposition of an equation to estimate the effective transferred energy to the pile in the hammer stroke by means of the blow count (set) and the elastic rebound. The study also devoted a section to the issue of dynamic compression stresses during driving, evaluating it through Gambini\'s Equation and proposing two alternative versions of that formula: a simplified one and a practical formulation in order to enable field estimations.
78

Un rebond au singulier pluriel : l'après-transmission du cédant mature en PME / A singular-plural rebound : post-succession of the mature SME transferor

Stéphan, Sylvie 23 October 2012 (has links)
L’objet de la présente recherche vise à donner un éclairage théorique, empirique et pratique de l’après-transmission du point de vue du cédant, qui a transmis sa PME saine ou apparemment saine, pour un motif autre que la retraite. A la suite de l’étude d’un cas pilote, la recherche s’oriente vers l’investigation de l’après-transmission volontaire du cédant mature en PME, comme opportunité de rebond pluridimensionnel. Le cadre conceptuel procède des théories du développement psychosocial à mi-vie, du développement du style cognitif de l’adulte, des stratégies de réinvestissement et du concept d’identité plurielle. Fondés sur une étude de cas multiples composée de huit unités d’analyse, les résultats résident dans la compréhension de la dynamique de rebond du cédant mature en PME (1), la modélisation du processus de rebond associé à l’évolution du statut du cédant-réinvestisseur (2) et la formulation d’une taxonomie des trajectoires individuelles de rebond (3). Au final, l’après-transmission du cédant mature en PME se révèle être un rebond au singulier pluriel. / The aim of the present research is to provide a theoretical, empirical and practical exploration of post- succession, from the perspective of the transferor who has transferred a healthy or apparently healthy SME for a reason other than retirement. Following a pilot case study, the research focused on the investigation of the voluntary post-succession of the mature SME transferor, as an opportunity for pluridimensional rebound. The conceptual framework emerges from theories of midlife psychosocial development, adult cognitive style development and reinvestment strategy and the concept of multiple identities. Based on a study of multiple cases, using eight units of analysis, the results lead to the understanding of the rebound dynamics of the mature SME transferor (1), modelling of the rebound process associated with the development of the status of transferor/reinvestor (2) and the formulation of a taxonomy of individual rebound trajectories (3). Finally, the post- succession of the mature SME transferor is revealed to be a “singular-plural” rebound.
79

Green consumption energy use and carbon dioxide emission

Alfredsson, Eva January 2002 (has links)
The aim of this thesis is to explore the quantitative potential to reduce energy requirements and CO2 emissions through changed patterns of consumption, given unchanged levels of consumption expenditure. The thesis question is analysed using a systems analysis approach which in this case means that life cycle assessment data on energy requirements and CO2 emissions related to household consumption are combined with a financial and behavioural analysis to make sure that the budget constraint is kept and that both the first and second order effects of adopting a green consumption pattern are analysed. The budget constraints are kept using a general linear model. By using marginal propensities to spend to direct the reallocation of saved or deficit money calculated utility is maintained as far as possible. Further, investigations explore the impact of individual household demographic characteristics and geographic context on household consumption patterns, energy requirements and CO2 emissions. The key result of this thesis is that changed household behaviour, choosing “green“ products and energy efficient technology will not make a big difference. What can be achieved in the short time perspective by adopting an almost completely green consumption pattern and energy efficient technology is a reduction of energy requirements by around 8% and CO2 emissions by around 13%. With a longer time perspective and further technological change that provides additional possibilities to move consumption patterns in a greener direction, the effect on energy requirements and CO2 emissions is still fairly small. By 2020, the potential to reduce energy requirements is around 13% and CO2 emissions around 25%. In the most extreme scenario (2050), the scope for reducing energy requirements is 17% and for CO2 emissions 30%. All these reductions will be outpaced by growth in income almost as soon as they are implemented. Of policy relevance the results reveal that very limited impact can be expected by a policy relying on greener consumption patterns, whether adopted voluntarily or as a result of incentives such as tax changes. Such a policy cannot achieve more than a small and temporary reduction to growth in energy requirements and CO2 emissions. It is also shown that, prescribing specific consumption patterns as a means of reducing energy requirements and CO2 emissions has to be done with care. This is illustrated by one of the experiments in which adopting a partly green consumption pattern, a green diet, in fact increased total energy requirements and CO2 emissions. This, and the results of all the other experiments show the importance of applying a systems approach. It demonstrates that life cycle data alone are irrelevant for assessing the total effects of adopting green consumption patterns. Further research on the potential to reduce energy requirements and CO2 emissions thus primarily needs to better capture system wide effects rather than to improve on, and fine tune the measurement of the energy requirements and CO2 emissions related to individual products.
80

Koldioxidlagring - realitet eller utopi? : En komparativ fallstudie med syfte att undersöka potentialen för koldioxidlagring i geologiska formationer och biologiska sänkor och dess förmåga att bidra till hållbar utveckling

Holgerson, Line January 2013 (has links)
To curb greenhouse gases and mitigate climate change is one of the biggest challenges human society face today. Carbon dioxide (CO2) has accumulated rapidly in the atmosphere as a consequence of burning of fossil fuels and deforestation. The aim of this study is to explore two methods to store carbon dioxide in geological formations and biological sinks. The aim is also to discuss the two mitigation options from a sustainable perspective and whether it can lead to a better environment and benefits for local and global societies. The research questions are: Which method to store carbon dioxide, geological or biological, is the most effective? Which method to store carbon dioxide, geological or biological, has the greatest potential to promote sustainable development for local communities? The method used is a comparative case study and presents four case studies that explore the potential for CO2 storage offshore in Norway and Brazil; and in tropical forests in Mexico and Brazil. The mitigation options are discussed from two different theoretical perspectives. The principle of the theory of ecological modernisation is that innovation and environmentally friendly technology can solve the environmental problems human societies face today, whereas the theory of common pool resources promotes local communities to govern limited resources in order to manage them sustainably. The findings suggest that ecological modernisation legitimize environmental destruction as carbon dioxide storage in geological formations (CCS) use the technology as a mean to extract more oil and gas; which results in a rebound-effect. Therefore, carbon dioxide capture in geological formations is not a realistic method unless it can prevent further emissions. Protected forest resources can be seen as biological insurance, which safeguard ecosystem services, biodiversity, and the forest potential to hold carbon. Carbon sequestration in tropical forest has the potential to store carbon dioxide given that the forests are protected and local communities have tenure rights, knowledge, and the means to protect the forest and manage them sustainably.

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