1,376 research outputs found

    Thermosetting polymer-matrix composites for structural repair applications

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    Several classes of thermosetting polymer matrix composites were evaluated for use in structural repair applications. Initial work involved the characterization and evaluation of woven carbon fiber/epoxy matrix composites for structural pipeline repair. Cyanate ester resins were evaluated as a replacement for epoxy in composites for high-temperature pipe repair applications, and as the basis for adhesives for resin infusion repair of high-temperature composite materials. Carbon fiber/cyanate ester matrix composites and fumed silica/cyanate ester nanocomposites were evaluated for their thermal, mechanical, viscoelastic, and rheological properties as they relate to their structure, chemistry, and processing characteristics. The bisphenol E cyanate ester under investigation possesses a high glass transition temperature, excellent mechanical properties, and unique ambient temperature processability. The incorporation of fumed silica served to enhance the mechanical and rheological properties of the polymer and reduce thermal expansion without sacrificing glass transition or drastically altering curing kinetics. Characterization of the composites included dynamic mechanical analysis, thermomechanical analysis, differential scanning calorimetry, thermogravimetric analysis, rheological and rheokinetic evaluation, and transmission electron microscopy

    Impact of configuration variations on small modular reactor core performance

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    One of the most promising new reactor designs is the Small Modular Reactor (SMR). These reactors, which operate under 300 MWe, will help bring cheap and safe nuclear energy to remote and centralized locations alike. Their ease of construction, advanced passive safety features, and cost effectiveness make these reactors an intriguing option for the near future. In the work presented here, a neutronics analysis of the Westinghouse SMR was performed. Westinghouse\u27s SMR design is a scaled down version of their AP1000 plant and will produce about 225 MWe of power. Though the parameters of the reactor core will be modeled after the AP1000, the exact layout of the core has not been released. For this research project, six initial core configurations have been proposed. The Monte Carlo method was used to calculate several reactor parameters by means of the MCNP6 code. Beginning of life calculations such as effective multiplication factor, delayed neutron fraction, temperature coefficients of reactivity, and neutron flux profile have been performed. Three refueling cycles have then been completed to observe how the six cores perform within the cycle up to the point when an equilibrium fuel cycle has been reached, while extracting data pertaining to multiplication factor, burnup, composition of spent fuel, and flux profile. These calculations will help to determine the feasibility and the effectiveness of the six potential core configurations. --Abstract, page iii

    Visual and Expressive Form Qualities Attainable in Thrown Pottery Vessels by Use of Various Lips and Feet

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    It was the purpose of this study to discover the number of various form qualities that it is possible to achieve within pottery vessels that are closely related by similar feet, bodies, and lips. The variety of form qualities sought for were of a visual nature; the entire pot seeming to appear more or less vertical or more or less horizontal than others with the same type of body but with different shapes of lips and feet selected to be used

    A chapter in the history of Orange County, Virginia

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    In 1753 Orange County could hardly have still been oalled a frontier region, but its society remained like that of the more exposed communities to the west for some time. It was neither overpopulated nor was the land intensively cultivated. The flora and fauna had hardly been affected, and wolves frequently howling at night reminded the inhabitants that the job of taming their environment was yet unfinished. These wolves were suffi­ ciently destruotive to demand bounties, and many farmers, planters and. gentlemen eked out their income by presenting the head of a wolf to the sheriff, who paid a hundred pounds of tobacco for the trophy

    A system of industrialized housing for developing countries

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    Thesis (M.Arch)--Massachusetts Institute of Technology, Dept. of Architecture, 1962.Accompanying drawings held by MIT Museum.Includes bibliographical references (leaves 30-31).by William Kirby Lockard.M.Arc

    The Golden Dog (Le Chien D\u27or)

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    https://commons.und.edu/settler-literature/1139/thumbnail.jp

    Up to D[eb]ate on Raising and Control, Part 2: The Empirical Range of the Constructions and Research on their Acquistion

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    This is the second part of a two-part article that reviews a number of the current debates regarding raising and control constructions. The issues addressed in this part include the spectrum of related raising (e.g. possessor raising, further raising) and control (partial, split, generic, super-equi) phenomena; cross-linguistic typology, including backward and copy constructions; and their acquisition in child language

    Young people's views on accelerometer use in physical activity research : findings from a user involvement investigation

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    The use of accelerometers to objectively measure physical activity is important in understanding young people's behaviours, as physical activity plays a key part in obesity prevention and treatment. A user-involvement qualitative study with young people aged 7–18years (n = 35) was carried out to investigate views on accelerometer use to inform an obesity treatment research study. First impressions were often negative, with issues related to size and comfort reported. Unwanted attention from wearing an accelerometer and bullying risk were also noted. Other disadvantages included feeling embarrassed and not being able to wear the device for certain activities. Positive aspects included feeling "special" and having increased attention from friends. Views on the best time to wear accelerometers were mixed. Advice was offered on how to make accelerometers more appealing, including presenting them in a positive way, using a clip rather than elastic belt to attach, personalising the device, and having feedback on activity levels. Judgements over the way in which accelerometers are used should be made at the study development stage and based on the individual population. In particular, introducing accelerometers in a clear and positive way is important. Including a trial wearing period, considering practical issues, and providing incentives may help increase compliance

    Second-quantized fermionic operators with polylogarithmic qubit and gate complexity

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    We present a method for encoding second-quantized fermionic systems in qubits when the number of fermions is conserved, as in the electronic structure problem. When the number FF of fermions is much smaller than the number MM of modes, this symmetry reduces the number of information-theoretically required qubits from Θ(M)\Theta(M) to O(FlogM)O(F\log M). In this limit, our encoding requires O(F2log4M)O(F^2\log^4 M) qubits, while encoded fermionic creation and annihilation operators have cost O(F2log5M)O(F^2\log^5 M) in two-qubit gates. When incorporated into randomized simulation methods, this permits simulating time-evolution with only polylogarithmic explicit dependence on MM. This is the first second-quantized encoding of fermions in qubits whose costs in qubits and gates are both polylogarithmic in MM, which permits studying fermionic systems in the high-accuracy regime of many modes.Comment: up to date with published version; 19 pages, 4 figure
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