• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 23
  • 9
  • 7
  • 2
  • 1
  • 1
  • Tagged with
  • 45
  • 21
  • 17
  • 12
  • 10
  • 9
  • 8
  • 7
  • 7
  • 7
  • 7
  • 7
  • 7
  • 6
  • 6
  • 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.
41

An?lise do comportamento mec?nico de concretos refor?ados com fibras e adi??o de res?duo de fresado asf?ltico / Analysis of the mechanical behavior of reinforced concrete with fibers and addition of asphalt milling residue

Martins, Jo?o Victor Rodrigues 27 June 2018 (has links)
Submitted by SBI Biblioteca Digital (sbi.bibliotecadigital@puc-campinas.edu.br) on 2018-08-14T11:38:43Z No. of bitstreams: 1 Jo?o Victor Rodrigues Martins.pdf: 6347531 bytes, checksum: da963af88129f7568a2e10f7c530b612 (MD5) / Made available in DSpace on 2018-08-14T11:38:43Z (GMT). No. of bitstreams: 1 Jo?o Victor Rodrigues Martins.pdf: 6347531 bytes, checksum: da963af88129f7568a2e10f7c530b612 (MD5) Previous issue date: 2018-06-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Funda??o de Amparo ? Pesquisa do Estado de S?o Paulo (FAPESP) / The process of assembling the reinforcement and the density of the concrete in structural pieces demand time and displacement of labor. The use of reinforcement with fibers in partial replacement of the transverse reinforcement could reduce the time of manufacture and facilitate the densification of the parts. Given this scenario, this research aimed at the study of concrete reinforced with fibers and reinforced concrete beams, in order to verify their behavior. Traces of concrete reinforced with steel fibers and traces of concrete with alkali-resistant glass fibers were made. In addition, the asphaltic milling residue was used for partial replacement of the small and large aggregate in the percentage of 15%. The material characterization was performed according to ABNT standards. Tests were performed to evaluate the Compressive Strength, Indirect Traction, Elasticity Modulus, and Tenacity through the Barcelona and ASTM C-1399 Tests. The evaluation of the mechanical behavior was performed by means of four-point bending in reinforced concrete beams, aiming to show its behavior to the applicant efforts. The results show the positive effect of the fibers for concrete with residues in their composition, mainly with respect to the steel fibers. It was verified a greater performance of the fibers as the Residual Resistance of the concrete and its Tenacity. It was also apresentated the viability of the structural application of asphalt milling residue as partial replacement of natural aggregates. / O processo de montagem da armadura e do adensamento do concreto em pe?as estruturais demandam tempo e deslocamento de m?o de obra. O uso do refor?o com fibras em substitui??o parcial da armadura transversal poderia reduzir o tempo de fabrica??o e facilitar o adensamento das pe?as. Diante de tal cen?rio, esta pesquisa visou o estudo de concretos refor?ados com fibras e de vigas de concreto armado, a fim de verificar seu comportamento. Foram confeccionados tra?os de concretos refor?ados com fibras de a?o e tra?os de concretos com fibras de vidro ?lcali-resistentes. Ademais foi utilizado o res?duo de fresado asf?ltico para substitui??o parcial do agregado mi?do e gra?do na porcentagem de 15%. A caracteriza??o dos materiais foi realizada conforme as normas da ABNT. Foram realizados ensaios para an?lise da Resist?ncia a Compress?o, da Tra??o Indireta, do Modulo de Elasticidade, da Tenacidade por meio dos Ensaios Barcelona e ASTM C-1399. A avalia??o do comportamento mec?nico foi realizada por meio de flex?o em quatro pontos em vigas de concreto armado, visando mostrar o seu comportamento aos esfor?os solicitantes. Os resultados revelam o efeito positivo das fibras para concretos com res?duos em sua composi??o, principalmente no que diz respeito as fibras de a?o. Foi verificada maior atua??o das fibras quanto a Resistencia Residual do concreto e a sua Tenacidade. Demonstrou-se tamb?m a viabilidade da aplica??o estrutural do res?duo de fresado asf?ltico como substitui??o parcial de agregados naturais.
42

Concreto com fresado asf?ltico aplicado em dispositivos de prote??o e drenagem de obras vi?rias / Concrete with recycled asphalt pavement applied in protection devices and drainage of road works

Ruiz, Adilson Nunes 07 February 2017 (has links)
Submitted by SBI Biblioteca Digital (sbi.bibliotecadigital@puc-campinas.edu.br) on 2017-03-23T14:31:48Z No. of bitstreams: 1 Adilson Nunes Ruiz.pdf: 6007533 bytes, checksum: 99ead3c6678aa04d133ce01f857fe6f0 (MD5) / Made available in DSpace on 2017-03-23T14:31:48Z (GMT). No. of bitstreams: 1 Adilson Nunes Ruiz.pdf: 6007533 bytes, checksum: 99ead3c6678aa04d133ce01f857fe6f0 (MD5) Previous issue date: 2017-02-07 / Funda??o de Amparo ? Pesquisa do Estado de S?o Paulo - FAPESP / In view of the large volume of waste generated by the construction industry coupled with the growing understanding of environmental preservation by the population, it was necessary to carry out studies with the firm intention of reusing these wastes. This work focuses on the residues generated in the area of road pavement construction, especially those resulting from the maintenance, restoration and improvement of roads paved with asphalt concrete. As the use of this material is not always carried out in a technical and adequate way, even though several studies are directed to the good technique of using recycled asphalt pavement, this work intends to present another technical form for the application of this important residue, to use in the construction of rigid concrete barriers and in gutters, half wire and gutters. These services normally run within the road works, that is, it aims to keep the material generated within the limits of the generating source. In order to achieve this, studies focused on meeting the technical specifications of the National Department of Infrastructure and Transport (DNIT) and the Department of Roads of the State of S?o Paulo (DER-SP), minimizing the output of milling from the generating source, considering that these public agencies are the main sources of this waste and performers of the services for which it is intended. This study compared the physical characteristics of conventional concrete and concrete with embedded asphalt milling, thus evaluating its technical, economic feasibility and environmental. The study was carried out in concrete with a characteristic compressive strength of 25MPa, intended for road safety elements, and at 20MPa for surface drainage elements. It was observed that the increase of recycled asphalt pavement in the concrete mixture directly influences the mechanical resistance, reducing its resistant capacity. When analyzing the substitution content of recycled asphalt pavement in the mix, it was found that percentages higher than 15% substantially affect the concrete's strength properties. The concrete with recycled asphalt pavement presents less rise and absorption of water by capillarity, as well as less absorption in the test of immersion, important qualities for mixtures that will be destined to the manufacture of structures that will be exposed to the elements or the contact with the water. The use of this residue in the concrete generates reduction in the cost of manufacture, besides providing reduction of the emission of greenhouse gases (CO2). In Brazil, it can be estimated that the use of asphalt milling in the concretes studied, can generate the approximate annual reduction of 270 thousand tCO2, besides saving approximately US$ 97 million/year through the sale of CO2 ("green" income) And the reduction of costs with the acquisition of natural raw materials extracted from deposits (sand and crushed stone), as well as to finance with this amount the construction of approximately 23 thousand popular residences of 40m2. / Tendo em vista o grande volume gerado de res?duos pela ind?stria da constru??o aliado ao fato do crescente entendimento pela popula??o da preserva??o ambiental, fez-se necess?ria a realiza??o de estudos com o firme prop?sito de reutiliz?-los. Este trabalho foca no res?duo gerado na ?rea da constru??o de pavimenta??o vi?ria, principalmente naqueles advindos das obras de manuten??o, restaura??o e melhoria do leito vi?rio pavimentado revestido com concreto asf?ltico. Como a utiliza??o deste material ? realizada nem sempre de forma t?cnica e adequada, mesmo tendo diversos estudos direcionados ? boa t?cnica de utiliza??o do fresado asf?ltico, este trabalho tem a pretens?o de apresentar mais uma forma t?cnica para a aplica??o deste importante res?duo, o de utilizar na constru??o de barreiras r?gidas de concreto e em canaletas, meios fio e sarjetas. Servi?os estes normalmente executados dentro das obras vi?rias, ou seja, visa manter o material gerado dentro dos limites da fonte geradora. Para isso, foram realizados estudos focados em atender as especifica??es t?cnicas do Departamento Nacional de Infraestrutura e Transporte (DNIT) e do Departamento de Estradas de Rodagem do Estado de S?o Paulo (DER-SP) em parte das obras de seguran?a vi?ria e drenagem, tendo em vista que estes ?rg?os p?blicos tem o dom?nio das principais fontes geradoras deste res?duo e s?o executores dos servi?os ao qual se destina. Este estudo comparou as caracter?sticas f?sicas do concreto convencional e do concreto com fresado asf?ltico incorporado, avaliando assim a sua viabilidade t?cnica, econ?mica e ambiental. O estudo foi realizado em concreto com resist?ncia caracter?stica ? compress?o de 25MPa, destinado a elementos de seguran?a vi?ria, e com 20MPa, para os elementos de drenagem superficial. Foi constatado que o incremento de fresado asf?ltico na mistura do concreto influencia diretamente nas resist?ncias mec?nicas, reduzindo sua capacidade resistente. Ao analisar o teor de substitui??o de fresado asf?ltico na mistura, foi constatado que percentuais superiores a 15% afetam substancialmente as propriedades mec?nicas do concreto. O concreto com fresado asf?ltico apresenta menor ascens?o e absor??o de ?gua por capilaridade, bem como menor absor??o no ensaio de imers?o, qualidades importantes para misturas que ser?o destinadas ? fabrica??o de estruturas que ficar?o expostas ?s intemp?ries ou ao contato com a ?gua. O uso deste res?duo no concreto gera redu??o no custo de fabrica??o, al?m de proporcionar redu??o da emiss?o de gases do efeito estufa (CO2). No Brasil, pode-se estimar que o uso do fresado asf?ltico nos concretos estudados, pode gerar a redu??o anual aproximada de 270mil tCO2, al?m de possibilitar economia aproximada de US$ 97 milh?es/ano atrav?s da comercializa??o do CO2 (renda ?verde?) e da redu??o de custos com a aquisi??o de mat?rias primas naturais extra?das de jazidas (areia e pedra britada), bem como financiar com este valor a constru??o de aproximadamente 23mil resid?ncias populares de 40m?.
43

Integrerad arbetsmiljöplanering

Rasouli, Mohammad January 2017 (has links)
Since the early 1980s, several   research programs initiated in the construction industry with the aim of   achieving a better working environment and more codetermination in the   planning of construction projects. Integrated planning (IP) was a project   carried out in 1985-1988 as a collaboration with Lund University, companies   in the construction industry and the trade unions in the afore-mentioned   area. The integrated planning concept was developed and implemented in the   construction industry in building production. IP is a model for integrating   production planning with systematic work environment planning and integrating   the skills of all participants in building production planning from early   stage to finish. The purpose of this study is to assess the extent to which   the work environment plan is a governing document during the ongoing work   environment planning before and during construction. Work Environment Act   (AML) and its provisions (AFS 1999: 3, AFS 2001: 1 and AFS 2015: 4) are   governing for the planning of the working environment in a construction   project. Based on the provisions, the report's research questions focus on   how and at what stage a work environment plan is established, as well as how   the model integrated planning is used in the ongoing work environment   planning prior to construction start and during the production phase. Of the   companies included in the study, three of them, Skanska, Peab and NCC are   Sweden's largest company and work on a national and international scale. The   third is INAB, a small company that mainly works nationally. The results show   that work environment planning starts at an early stage with preventive   actions and routines during the building construction process and mainly   follow the same concept as the integrated planning model. Integrated work   environment planning (IWEP) is a model for building production planning that   can be used in any projects, whatever, its complexity and size. Tallåsen is a   clear example that shows the work environment plan is a governing document during   the production phase. More attention should be paid to the OSA (AFS 2015:4)   by implementing more practical preventive actio / <p>Betyg 170707, H14.</p>
44

Investigating the Effect of Phage Therapy on the Gut Microbiome of Gnotobiotic ASF Mice

Ganeshan, Sharita January 2019 (has links)
Mounting concerns about drug-resistant pathogenic bacteria have rekindled the interest in bacteriophages (bacterial viruses). As bacteria’s natural predators, bacteriophages offer a critical advantage over antibiotics, namely that they can be highly specific. This means that phage therapeutics can be designed to destroy only the infectious agent(s), without causing any harm to our microbiota. However, the potential secondary effects on the balance of microbiota through bacteriophage-induced genome evolution remains as one of the critical apprehensions regarding phage therapy. There exists a significant gap in knowledge regarding the direct and indirect effect of phage therapeutics on the microbiota. The aim of this thesis was to: (1) establish an in vivo model for investigation of the evolutionary dynamics and co-evolution of therapeutic phage and its corresponding host bacterium in the gut; (2) determine if phage therapy can affect the composition of the gut microbiota, (3) observe the differences of phage-resistant bacteria mutants evolved in vivo in comparison to those evolved in vitro. We used germ-free mice colonized with a consortium of eight known bacteria, known as the altered Schaedler flora (ASF). The colonizing strain of choice (mock infection) was a non-pathogenic strain E. coli K-12 (JM83) known to co-colonize the ASF model, which was challenged in vivo with T7 phage (strictly lytic). We compared the composition of the gut microbiota with that of mice not subject to phage therapy. Furthermore, the resistant mutants evolved in vivo and in vitro were characterized in terms of growth fitness and motility. / Thesis / Master of Applied Science (MASc) / Bacteriophages are viruses that infect bacteria. After their discovery in 1917, bacteriophages were a primary cure against infectious disease for 25 years, before being completely overshadowed by antibiotics. With the rise of antibiotic resistance, bacteriophages are being explored again for their antibacterial activity. One of the critical apprehensions regarding bacteriophage therapy is the possible perturbations to our microbiota. We set out to explore this concern using a simplified microbiome model, namely germ-free mice inoculated with only 8 bacteria plus a mock infection challenged with bacteriophage. We monitored this model for 9 weeks and isolated a collection of phage-resistant bacterial mutants from the mouse gut that developed post phage challenge, maintaining the community of mock infection inside the gut. A single dose of lytic phage challenge effectively decreased the mock infection without causing any extreme long-term perturbations to the gut microbiota.
45

Wastescape Bhubaneswar &amp; Cuttack

Gudéhn, Oskar, Ringqvist, Linda January 2014 (has links)
This project is a study of the wastescape - a network of waste - of Bhubaneswar and Cuttack in Odisha, India.  The study incorporates key locations, e.g. landfills, urban wastelands and waste warehouses; major actors in the formal and informal waste sector; and flows of waste through economic and social systems. Drawing from the studies, multiple interventions within the wastescape are proposed for improvement of the economic, ecologic and social situation. An important aspect of the project is the development of an approach for how to, as architects, work with big, complex, contingent networks; how to map and understand such a system; and how to determine where to intervene. To improve the existing wastescape, interventions must consciously and holistically address multiple scales; levels of formal-informal; and phases within the waste cycle. The study includes a vast amount of possible interventions. Some of the interventions are further detailed to show feasibility; impact on the wastescape; and synergies with other interventions within the wastescape. / Projektet “Wastescape of Bhubaneswar &amp; Cuttack” är en studie av ett nätverk av skräpflöden genom Bhubaneswar och Cuttack i Odisha, Indien. Studien inkorporerar viktiga platser, t.ex. deponier, urbana ödemarker och lokaler för skräphandel; stora aktörer i den formella och informella skräpsektorn; och flöden av skräp genom ekonomiska och sociala system. Utifrån dessa studier, ett flertal interventioner i “the wastescape” föreslås för att förbättra den ekonomiska, ekologiska och sociala situationen. En viktig aspekt av arbetet är utvecklingen av ett sätt att, som arkitekt, arbeta med storskaliga, komplexa och inter-beroende nätverk; hur sådana system kan kartläggas och förstås; samt hur det går att avgöra vart och hur interventioner passar in i “the wastescape”. För att förbättra “the wastescape”, interventioner måste medvetet och holistiskt adressera multipla skalor; nivåer av formell-informell; och faser i skräpets kretslopp. Studien innehåller ett stort nummer av möjliga interventioner. Några av dessa interventioner är ytterligare detaljerade för att visa på genomförbarhet; påverkan på “the wastescape”; och synergier gentemot andra interventioner i “the wastescape”.

Page generated in 0.0514 seconds