7 resultados para Building material

em Digital Commons at Florida International University


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Construction projects are complex endeavors that require the involvement of different professional disciplines in order to meet various project objectives that are often conflicting. The level of complexity and the multi-objective nature of construction projects lend themselves to collaborative design and construction such as integrated project delivery (IPD), in which relevant disciplines work together during project conception, design and construction. Traditionally, the main objectives of construction projects have been to build in the least amount of time with the lowest cost possible, thus the inherent and well-established relationship between cost and time has been the focus of many studies. The importance of being able to effectively model relationships among multiple objectives in building construction has been emphasized in a wide range of research. In general, the trade-off relationship between time and cost is well understood and there is ample research on the subject. However, despite sustainable building designs, relationships between time and environmental impact, as well as cost and environmental impact, have not been fully investigated. The objectives of this research were mainly to analyze and identify relationships of time, cost, and environmental impact, in terms of CO2 emissions, at different levels of a building: material level, component level, and building level, at the pre-use phase, including manufacturing and construction, and the relationships of life cycle cost and life cycle CO2 emissions at the usage phase. Additionally, this research aimed to develop a robust simulation-based multi-objective decision-support tool, called SimulEICon, which took construction data uncertainty into account, and was capable of incorporating life cycle assessment information to the decision-making process. The findings of this research supported the trade-off relationship between time and cost at different building levels. Moreover, the time and CO2 emissions relationship presented trade-off behavior at the pre-use phase. The results of the relationship between cost and CO2 emissions were interestingly proportional at the pre-use phase. The same pattern continually presented after the construction to the usage phase. Understanding the relationships between those objectives is a key in successfully planning and designing environmentally sustainable construction projects.

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The aesthetic placement and period designation of Jorge Luis Borges (1899–1986) and José Lezama Lima (1910–1976) are complicated issues among critics. Borges is considered a predecessor of the Latin American literary “boom,” but despite that taxonomy his work transcends that definition and provides a foundation for new trends, such as the “neobarroco” cultivated by Severo Sarduy. Lezama is considered part of the second wave of the “boom,” but his work feeds, stylistically, from the Spanish baroque. At the same time, Lezama's daring treatment of homoeroticism and his system of images place him after the “boom” in a narrative style that is postmodern. This study undertakes a revision of external and internal issues, revealing the key fictive elements that characterize both writers. Through discourse analysis, a poetic system is formulated, which incorporates features of the “neobarroco,” and postmodern narrative styles. ^ This dissertation uses a polar structure to analyze both poetic visions and finds that they are symmetrical. From this perspective, Borges and Lezama belong to the “core” of literature that centers its emphasis in the creation of a system versus other modes of writing in which mimetic function prevails. By doing this and by recycling world culture, they create postmodern myth: the new building material for Hispanic American literature. ^ There are a few studies that explore the works of Borges and Lezama within the context of Baroque aesthetics. This dissertation offers a comprehensive analysis that considers their poetic visions at large. Besides the difference in perspective, defined as macro-spatial in Borges and micro-spatial in Lezama, there are many similarities. Both writers question the cause and effect relationship and the use of metaphor. They share a redefinition of genre as well as a hedonistic approach to literature. This kinship in poetic vision is revealed through the polar method used for this study, which proposes a new form of aesthetic placement and period designation. ^

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The aesthetic placement and period designation of Jorge Luis Borges (1899-1986) and José Lezama Lima (1910-1976) are complicated issues among critics. Borges is obviously considered a predecessor of the Latin American literary “boom,” but despite that taxonomy his work transcends that definition and provides a foundation for new trends and styles, such as the “neobarroco” cultivated by Severo Sarduy. Lezama is considered part of the second wave of the “boom,” but his work feeds, stylistically, from the Spanish baroque. At the same time, Lezama’s daring treatment of homoeroticism and his revolutionary system of images place him after the “boom” in a narrative style that is postmodern. This study undertakes a thorough revision of external and internal issues, revealing the key linguistic and fictive elements that characterize both writers. Through discourse analysis and close reading, a poetic system is formulated, which incorporate features of the “neobarroco,” “boom” and postmodern narrative styles. This dissertation uses a polar structure to analyze both poetic visions and concludes that they are compatible and symmetrical. From this perspective, Borges and Lezama belong to the “core” of literature that centers its emphasis in the creation of a system versus other modes of writing in which mimetic function prevails. By doing this and by recycling world culture, they create postmodern myth: the new building material for Hispanic American literature. There are only a few studies that explore the works of Borges and Lezama within the context of Baroque aesthetics. For the first time, this dissertation offers a comprehensive analysis that considers their poetic visions at large. Besides the difference in perspective, defined as macro-spatial in Borges and micro-spatial in Lezama, there are many similarities in content and form. Both writers question the cause and effect relationship and the modern use of metaphor. They also share a redefinition of genre as well as a hedonistic approach to literature and culture. This kinship in poetic vision is revealed through the polar method used for this study, which proposes a new form of aesthetic placement and period designation.

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In this thesis, results of the investigation of a new low-dimensional cobaltates Ba2-xSrxCoO 4 are presented. The synthesis of both polycrystalline and single crystalline compounds using the methods of conventional solid state chemical reaction and floating-zone optical furnace is first introduced. Besides making polycrystalline powders, we successfully, for the first time, synthesized large single crystals of Ba2CoO4. Single crystals were also obtained for Sr doped Ba2-xSrxCoO 4. Powder and single crystal x-ray diffraction results indicate that pure Ba2CoO4 has a monoclinic structure at room temperature. With Sr doping, the lattice structure changes to orthorhombic when x ≥ 0.5 and to tetragonal when x = 2.0. In addition, Ba2CoO4 and Sr2CoO4, have completely different basic building blocks in the structure. One is CoO4 tetrahedron and the later is CoO6 octahedron, respectively. Electronic and magnetic properties were characterized and discussed. The magnetic susceptibility, specific heat and thermal conductivity show that Ba2CoO4 has an antiferromagnetic (AF) ground state with an AF ordering temperature TN = 25 K. However, the magnitude of the Néel temperature TN is significantly lower than the Curie-Weiss temperature (:&thetas;: ∼ 110 K), suggesting either reduced-dimensional magnetic interactions and/or the existence of magnetic frustration. The AF interaction persists in all the samples with different doping concentrations. The Néel temperature doesn't vary much in the monoclinic structure regime but decreases when the system enters orthorhombic. Magnetically, Ba2CoO4 has an AF insulating ground state while Sr2CoO4 has a ferromagnetic (FM) metallic ground state. Neutron powder refinement results indicate a magnetic structure with the spin mostly aligned along the a-axis. The result from a μ-spin rotation/relaxation (μ+SR) experiment agrees with our refinement. It confirms the AF order in the ab -plane. We also studied the spin dynamics and its anisotropy in the AF phase. The results from inelastic neutron scattering show that spin waves have a clear dispersion along a-axis but not along c-axis, indicating spin anisotropy. This work finds the strong spin-lattice coupling in this novel complex material. The interplay between the two degrees of freedom results an interesting phase diagram. Further research is needed when large single crystal samples are available.

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Small states that lack capacity and act on their own may fall victim to international and domestic terrorism, transnational organized crime or criminal gangs. The critical issue is not whether small Caribbean states should cooperate in meeting security challenges, but it is rather in what manner, and by which mechanisms can they overcome obstacles in the way of cooperation. The remit of the Regional Security System (RSS) has expanded dramatically, but its capabilities have improved very slowly. The member governments of the RSS are reluctant to develop military capacity beyond current levels since they see economic and social development and disaster relief as priorities, requiring little investment in military hardware. The RSS depends on international donors such as the USA, Canada, Great Britain, and increasingly China to fund training programs, maintain equipment and acquire material. In the view of most analysts, an expanded regional arrangement based on an RSS nucleus is not likely in the foreseeable future. Regional political consensus remains elusive and the predominance of national interests over regional considerations continues to serve as an obstacle to any CARICOM wide regional defense mechanism. Countries in the Caribbean, including the members of the RSS, have to become more responsible for their own security from their own resources. While larger CARICOM economies can do this, it would be difficult for most OECS members of the RSS to do the same. The CARICOM region including the RSS member countries, have undertaken direct regional initiatives in security collaboration. Implementation of the recommendations of the Regional Task Force on Crime and Security (RTFCS) and the structure and mechanisms created for the staging of the Cricket World Cup (CWC 2007) resulted in unprecedented levels of cooperation and permanent legacy institutions for the regional security toolbox. The most important tier of security relationships for the region is the United States and particularly USSOUTHCOM. The Caribbean Basin Security Initiative [CBSI] in which the countries of the RSS participate is a useful U.S. sponsored tool to strengthen the capabilities of the Caribbean countries and promote regional ownership of security initiatives. Future developments under discussion by policy makers in the Caribbean security environment include the granting of law enforcement authority to the military, the formation of a single OECS Police Force, and the creation of a single judicial and law enforcement space. The RSS must continue to work with its CARICOM partners, as well as with the traditional “Atlantic Powers” particularly Canada, the United States and the United Kingdom to implement a general framework for regional security collaboration. Regional security cooperation should embrace wider traditional and non-traditional elements of security appropriate to the 21st century. Security cooperation must utilize to the maximum the best available institutions, mechanisms, techniques and procedures already available in the region. The objective should not be the creation of new agencies but rather the generation of new resources to take effective operations to higher cumulative levels. Security and non-security tools should be combined for both strategic and operational purposes. Regional, hemispheric, and global implications of tactical and operational actions must be understood and appreciated by the forces of the RSS member states. The structure and mechanisms, created for the staging of Cricket World Cup 2007 should remain as legacy institutions and a toolbox for improving regional security cooperation in the Caribbean. RSS collaboration should build on the process of operational level synergies with traditional military partners. In this context, the United States must be a true partner with shared interests, and with the ability to work unobtrusively in a nationalistic environment. Withdrawal of U.S. support for the RSS is not an option.

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Electromagnetic waves in suburban environment encounter multiple obstructions that shadow the signal. These waves are scattered and random in polarization. They take multiple paths that add as vectors at the portable device. Buildings have vertical and horizontal edges. Diffraction from edges has polarization dependent characteristics. In practical case, a signal transmitted from a vertically polarized high antenna will result in a significant fraction of total power in the horizontal polarization at the street level. Signal reception can be improved whenever there is a probability of receiving the signal in at least two independent ways or branches. The Finite-Difference Time-Domain (FDTD) method was applied to obtain the two and three-dimensional dyadic diffraction coefficients (soft and hard) of right-angle perfect electric conductor (PEC) wedges illuminated by a plane wave. The FDTD results were in good agreement with the asymptotic solutions obtained using Uniform Theory of Diffraction (UTD). Further, a material wedge replaced the PEC wedge and the dyadic diffraction coefficient for the same was obtained.

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