Página 14 dos resultados de 2122 itens digitais encontrados em 0.045 segundos

‣ Laboratory characterization of a highly weathered old alluvium in San Juan, Puerto Rico

Zhang, Guoping, 1968-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 334 p.; 28650743 bytes; 28650500 bytes; application/pdf; application/pdf
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The old alluvium underlying much of metropolitan San Juan was formed in early Pleistocene and has undergone substantial post-depositional weathering in the tropical climate of Puerto Rico, resulting in a special combination of soil mineralogy and structure, with very unusual engineering properties. The soil mineralogy was determined both qualitatively and quantitatively by a series of analytical techniques, consisting of X-ray diffraction, thermal analysis, X-ray fluorescence, and chemical analyses including cation exchange capacity (CEC), soil pH, and selective chemical dissolutions (SCD). Results show that the old alluvium contains: (1) two most weathering resistant primary minerals: quartz and orthoclase; (2) kaolinite and smectites as major clay minerals; and (3) Fe-oxides (goethite and hematite) as special fine-grained minerals, which give the soil distinct red, brown, and yellow coloration. The subsequent quantitative analysis yields high accuracy results, such that the identified mineral phases account for 94-95% of the bulk material. Characterization of soil microstructure also used a variety of techniques including environmental scanning electron microscope (ESEM), slaking tests, CEC, and SCD of Fe-oxides. The results reveal an aggregate structure comprising groups of clay platelets...

‣ Experiential learning environments for structural behavior

Viteri, Victor R. (Victor Raul)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 184 leaves; 16427226 bytes; 16427030 bytes; application/pdf; application/pdf
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Computers have dramatically changed the nature of structural engineering practice by shifting work from process-oriented tasks, such as performing hand calculations and drafting, to structural modeling and interpretation of computer results. To perform these new functions, engineers need to have a deep understanding of structural behavior. There exists, however, a strong sentiment that engineering education has not been able to effectively address these new needs. Through the Experiential Learning Cycle, this research identifies structural behavior as knowledge associated with conceptual understanding that is most effectively attained through reflective action. Within this context, an epistemological analysis reveals that the use of computer applications that integrate simulation and assessment capabilities would enhance the traditional framework of structural engineering education. The Tutorial Cycle provides the pedagogical foundation for the development of a methodology that leads to the creation of such environments. The principles proposed by this methodology were implemented in the building of an Experiential Learning Environment whose primary objective is to help develop a qualitative understanding for the structural behavior of beams. In order to address conceptual and developmental issues...

‣ Use of fiber reinforced polymer composite in bridge structures; Use of FRP in bridge structures

Tuakta, Chakrapan, 1980-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 50 leaves; 2551286 bytes; 2555317 bytes; application/pdf; application/pdf
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Fiber reinforced polymer composite (FRP) is a new construction material, gradually gaining acceptance from civil engineers. Bridge engineering is among the fields in civil engineering benefiting from the introduction of FRP composite. Its advantages over traditional construction materials are its high tensile strength to weight ratio, ability to be molded into various shapes, and potential resistance to environmental conditions, resulting in potentially low maintenance cost. These properties make FRP composite a good alternative for innovative construction. In the past 10 years, experiments have been conducted to investigate the applicability of FRP composite in bridge structures, including the applications of FRP composite girder and bridge deck, column and beam strengthening, etc. This document will first present the basic information of FRP composite, including its mechanical behaviors and manufacturing processes relevant to civil engineering applications. Then the application of FRP composite in bridge engineering will be investigated, through three case studies. Four main issues contributing to the slow acceptance of the material into construction industry as a whole, despite its success in aerospace and automobile industries...

‣ Structural feasibility of a medium-rise timber office building

Nasr, Mohsen, 1981-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 85 leaves; 6541054 bytes; 6550430 bytes; application/pdf; application/pdf
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Using timber as a structural material for commercial projects will certainly gain importance and popularity in the coming decades as more focus is placed on reducing environmental effects created by a dependence on steel and concrete in the construction industry. Timber is a clean alternative that despite its historical use is too often overlooked by designers when they are choosing materials for ordinary commercial projects like office buildings. This thesis presents a case for using timber as the primary structural material in a medium-rise office building (up to ten stories), where currently only concrete and steel are normally used. The study accomplishes this using a custom structural design for a typical office building and exploring the structural issues that presumably prohibit timber from being used more commonly. Such issues are strength capacity, stiffness, material reliability, natural defects, area of required material, fire protection, and constructability. Addressing these issues in terms of building codes and in general comparison to steel and concrete makes up the bulk of the feasibility study. Future work essential to completing the structural case for timber is also identified, and the study concludes that timber is indeed a viable alternative material in typical office building design. The motivation behind the thesis is one based on obtaining and sharing an introduction to a material that finds little application in traditional engineering education yet will grow to play a large role in the field of structural engineering in the coming age of sustainability-minded design.; by Mohsen Nasr.; Thesis (M. Eng.)--Massachusetts Institute of Technology...

‣ Evolution in the design and construction of stadiums

Mezher, Jad F. (Jad Farid), 1978-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 59 leaves; 4504523 bytes; 4504330 bytes; application/pdf; application/pdf
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by Jad F. Mezher.; Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.; Includes bibliographical references (leaves 58-59).

‣ On the design of a kinetic adaptive structural surface with reference to nature, form and simplicity

Kassabian, Paul E. (Paul Edward), 1974-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 100 p.; 5808084 bytes; 5807889 bytes; application/pdf; application/pdf
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Paul E. Kassabian.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.; Includes bibliographical references (p. 89-90).

‣ Utilization of information management systems for sustainable infrastructure planning; Utilization of information management systems for sustainable and resilient infrastructure planning

Gourley, James Steven, 1978-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 70 p.; 4560903 bytes; 4560712 bytes; application/pdf; application/pdf
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by James Steven Gourley.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.; Includes bibliographical references (p. 67-70).

‣ Extended discrete choice models : integrated framework, flexible error structures, and latent variables

Walker, Joan Leslie
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 209 leaves; 13077075 bytes; 13089818 bytes; application/pdf; application/pdf
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by Joan Leslie Walker.; Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2001.; Includes bibliographical references (leaves 199-209).

‣ Size distributions, population dynamics, and single-cell properties of marine plankton in diverse nutrient environments

Cavender-Bares, Kent Keller, 1966-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 208 p.; 10312201 bytes; 10320951 bytes; application/pdf; application/pdf
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by Kent Keller Cavender-Bares.; Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1999.; Includes bibliographical references.

‣ Private finance initiative and major construction firms in Japan

Kato, Koji, 1964-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 144 p.; 16753587 bytes; 16764612 bytes; application/pdf; application/pdf
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by Koji Kato.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2001.; Includes bibliographical references (p. 240-244).

‣ Offshoring is not the panacea : ensuring sustainable employment in the US manufacturing industry by leveraging demand proximity; Ensuring sustainable employment in the US manufacturing industry by leveraging demand proximity

Bartolin, Alexandre (Alexandre Fernand Sauveur)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 216 p.; 42653169 bytes; 42652467 bytes; application/pdf; application/pdf
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This thesis investigates the theme of "manufacturing offshoring" that became a political issue during the 2004 U.S. presidential election. As during previous elections, employment became a key focus on the home front. Whereas the 1992 presidential election was marked by the debate around the loss of manufacturing jobs due to NAFTA, the 2004 election focused on both manufacturing and services jobs lost due to offshoring to low cost countries. For the first time, well paying jobs, such as IT programming, were outsourced to emerging countries like India or China. Offshoring of "white collar" jobs became the focus of academic, consultant, and journalist discussions in U.S., whereas offshoring of manufacturing activities generated comparatively less interest. For decades offshoring of manufacturing activities to low cost countries was used by American companies to either reduce production cost or to avoid high tariffs on exports. Offshoring strategy was historically applied in labor intensive industries, such as the apparel and electronics sectors. On the other hand, the influence of offshoring on high-tech industries was assumed to be limited. However, with the fast technological development of China and India, this paradigm might change quickly.; (cont.) This thesis explores the U.S. manufacturing sector by looking at employment and trade data at a macro-level. The terms offshoring and outsourcing will be defined and the main international trade theories discussed. The thesis develops a model to show that offshoring was only a part of the reason for the shrinkage in manufacturing employment between 1997 and 2003; the others being a drop in demand and gains in productivity. After introducing several case studies of companies in the apparel sector and the semi-conductor industry...

‣ Formulation and testing of a distributed triangular irregular network rainfall/runoff model

Rybarczyk, Scott Michael, 1974-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 186 p.
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by Scott Michael Rybarczyk.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000.; Includes bibliographical references (p. 178-186).

‣ Prospects for plug-in hybrid electric vehicles in the United States : a general equilibrium analysis; Prospects for PHEVs in the United States : a general equilibrium analysis

Karplus, Valerie Jean
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 80 p.
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The plug-in hybrid electric vehicle (PHEV) could significantly contribute to reductions in carbon dioxide emissions from personal vehicle transportation in the United States over the next century, depending on the cost-competitiveness of the vehicle, the relative cost of refined fuels and electricity, and the existence of an economy-wide carbon emissions constraint. Using a computable general equilibrium model, I evaluated the potential for the PHEV to enter the U.S. personal vehicle market before 2100 and alter electricity output, refined oil consumption, carbon dioxide emissions, and the economic welfare losses associated with the imposition of a strict climate policy. The PHEV is defined by its ability to run on battery-stored electricity supplied from the grid as well as on refined fuel in an internal combustion engine. Sectors that produce PHEV transportation as well as other electric-drive vehicle technologies were added to the MIT Emissions Prediction and Policy Analysis (EPPA) Model as a perfect substitute for internal combustion engine (ICE)-only vehicles. Engineering cost estimates for the PHEV, as well as information about the pre-existing fleet, were used to specify PHEV sector input shares and substitution elasticities in the model. Based on the model results...

‣ Wastewater treatment in Las Vegas, Santa Barbara, Honduras

Hodge, Matthew M
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 62 leaves
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The Municipality of Las Vegas, Honduras is located immediately to the west of Lake Yojoa, the largest inland lake in Honduras. Beginning in 2005, the Massachusetts Institute of Technology (MIT) began working with stakeholders around the lake to assess anthropogenic environmental impacts on the lake. In January 2008, a technical team composed of Dr. Eric Adams from MIT, Aridai Herrera a civil engineer from Malcolm Pirnie, and MIT students Anne Mikelonis and Matthew Hodge, traveled to Las Vegas to work with the Municipality on domestic wastewater discharge, one of the previously identified environmental impacts on Lake Yojoa. In preliminary discussions with the Municipality, the team identified three goals for the project: evaluate the performance of the existing wastewater treatment facility, test the possibility of enhancements to this facility, and evaluate options for expanded sewerage and wastewater treatment throughout Las Vegas. The results of this project are a set of three recommendations for the Municipality to improve wastewater treatment. First, regular maintenance of existing facilities is necessary to achieve optimal performance for existing wastewater infrastructure. Second, substantial non-waste water is entering the sewerage leading to an average daily flow of 1...

‣ Integrated product design and life-cycle assessment

Sousa, Inês (Maria Inês Silva Sousa), 1972-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 146 p.
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by Inês Sousa.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1998.; Includes bibliographical references (p. 111-114).

‣ Corporate value creation for Japan's construction firms in the shrinking and changing domestic market

Kanari, Masahiko, 1968-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 153 p.; 6495296 bytes; 6495103 bytes; application/pdf; application/pdf
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by Masahiko Kanari.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.; Includes bibliographical references (p. 149-153).

‣ Analysis of crack patterns in reinforced concrete frames under seismic excitation

Blé, Aurélie
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 44 leaves; 2228104 bytes; 2228143 bytes; application/pdf; application/pdf
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Earthquakes occur as a result of sudden displacements across a fault within the earth. The seismic waves that result from them propagate along the earth's surface and are the cause of multiple damages especially in civil engineering. The main objective of this study is to compare different types of concrete (RC, HSRC and SFRC) in order to determine the one that will contribute the most to increase the steadiness of buildings in seismic regions at the connection between beams and columns. The first part of this paper consists of introducing these different types of concrete. Then cracks patterns analyses are run at the joint between beam and column. In that part, theoretical approach precedes experimental application. Finally, explanation about benefits and advantages of using SFRC in joints of buildings subjected to seismic excitations will be provided. In fact, concrete reinforced with short steel fibers is associated with its ability to control cracking and enhances properties of concrete.; by Aurélie Blé.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2006.; Includes bibliographical references (leaves 41-42).

‣ Acoustic data communication system for in-pipe wireless sensor networks

Kokossalakis, George, 1976-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 294 p.
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Sustainability of aging infrastructure is one of the greatest current civil engineering challenges, especially in the case of pipelines, where no direct access is available. Being simultaneously massive and distributed, their normal operation is critical for the health and prosperity of the community. In current practice, the condition of pipelines is assessed by non-destructive inspection techniques. Nonetheless, frequent pipeline failures warrant the continuous assessment of their condition, in order to schedule the maintenance activities accordingly, and assure their safe operation. Continuous monitoring necessitates the deployment of autonomous wireless sensor networks (WSN). This thesis proposes solutions for the communication and power units of a WSN for monitoring underground water pipelines. Regarding the communication unit, it is proposed to use the pipeline as an acoustic waveguide for the transmission of appropriately modulated acoustic waves that encapsulate the digital data, since radio frequency transmission is not feasible underground. The confined acoustic channel imposes severe distortion on the propagating signal. In order to compensate for the dispersion and ambient noise, the proposed communication system employs an elaborate set of signal processing steps...

‣ A web-controllable shaking table for remote structural testing under seismic loading

Manasseh, Mazen, 1980-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 79 leaves; 3221753 bytes; 3221561 bytes; application/pdf; application/pdf
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The thesis presents a remotely accessible system for controlling a shaker table laboratory experiment. The Shake Table WebLab is implemented at MIT's Civil Engineering Department under the Microsoft-sponsored iLab initiative for the development of educationally-oriented virtual experiments. Facilitated accessibility, safe operation and expandability are essentials at the root of the design and implementation of the Shake Table WebLab. The fully functional system allows students and researchers to excite a two-story structure, which is three feet high, by vibrating its base while receiving accelerometer readings from its three levels. Registered Internet users may upload their own input data, such as the seismic ground acceleration of a newly occurring earthquake, and therefore study the corresponding behavior of a real structure. The system is designed with an expandable architecture which enables future researchers to add functionalities that suit their fields of interest. Relevant fields of study include real-time signal processing and filtering techniques that would provide an understanding of how earthquakes affect a structure and therefore provide insight on means to minimize encountered damage in large-scale structures. An already developed tool utilizes frequency domain transfer functions to compare the measured structural response at the upper levels with a predictable result based on seismic vibrations applied at the structure's base. Two main characteristics of the web-based application are interactivity...

‣ Implementing a wireless base station for a sensor network

Song, Heewon, 1977-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 69 leaves; 4756296 bytes; 4756103 bytes; application/pdf; application/pdf
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Using wireless sensor networks for monitoring infrastructure is a new trend in civil engineering. Compared with traditional ways to monitor infrastructure, wireless sensor networks are cheap, safe, and compact. However, there are many available wireless communication techniques and hardware for a wireless sensor network. Therefore, it is an important step to choose the best communication method and hardware to construct a wireless sensor network for a particular infrastructure. The London Underground project, which is described in this thesis as a reference case study, demands real-time data transmission, low-power network, and wireless network communication, and also a hardware/software system to collect, archive and display data from the monitoring activity. We consider the trade-offs in choosing 802.1 lb as a communication method. A web service architecture for data visualization is then described. Finally we discuss the appropriate selection of a computer device to serve as the base station.; by Heewon Song.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004.; Includes bibliographical references (leaves 68-69).