225 research outputs found

    Snow-Melting System, 9th Street and I 64, Louisville

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    The 9th Street - I 64 interchange in Louisville was equipped with an automated electrical heating system for snow and ice removal. The system is capable of maintaining a clear and safe passageway. This report summarizes the performance of the heating system and describes the factors that will influence future use of this or other nonconventional methods of snow and ice removal

    Evaluation of Watertight Bridge Expansion Joints

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    Engineers have long recognized the importance of bridge expansion joints. The inadequacy in design of such joints has also been realized. Proprietary products are now available which may eliminate well-documented problems associated with bridge expansion. The objective of this study was to evaluate the field performance of such products

    Heating the 9th Street Interchange: Construction and Initial Operation

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    The 9th-Street interchange was designed and constructed with an automated, electrical heating system for snow and fee removal. This report describes the heating system, its construction, and initial operation. The heating system was capable of keeping the interchange free of ice and snow accumulation. The average daily slab temperature fell below 32°F (0°C) on only one occasion. The average cost of electrical power for heating the interchange was $905 per day

    The Operation of an Electrical Heating System for Bridge Decks

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    The 9th-Street interchange with I 64 in Louisville, Kentucky, was designed and constructed with an automated electrical heating system for snow and ice removal. This report summarizes the operation of the heating system during the first four years. The system was capable of keeping the interchange free of ice and snow accumulation. The average daily slab temperature fell below 0°C (32° F) only on a few occasions. The average cost of electrical power for heating the interchange was $883 per day

    Cracking in Continuously Reinforced Concrete Pavements

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    The objective of this study was to monitor placement and evaluate performance of continuously reinforced concrete pavement with an emphasis on determining the time of cracking and crack interval. This paper reports on the design and construction practice for CRCP in Kentucky. Data on crack frequency and time of cracking is also included in an attempt to further explain the cracking pattern associated with CRCP

    Heating Bridge Decks by Electrical Resistance

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    The 9th-Street interchange was designed and constructed with an automated electrical heating system for snow and ice removal. This report describes the heating system, its construction, and initial operation. The heating system was capable of keeping the interchange free of ice and snow accumulation. The average daily slab temperature fell below 0°C (32°F) on only one occasion. The average cost of electrical power for heating the interchange was $1,075 per day

    Cracking in Concrete Pavement

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    Cracking of portland cement concrete pavements is a common, even expected, occurrence. To minimize potentially detrimental effects, it is necessary to understand mechanisms that might be used to explain such behavior so that measures may be developed and implemented to control the occurrence of such cracking. Several theories are discussed that might provide the mechanisms of pavement cracking. An alternate meachanism, based on fatigue loading of the concrete by temperature expansions-contrations, for the development of so-called D-cracking is offered

    A Longitudinal Method for Simultaneous Whole-Brain and Lesion Segmentation in Multiple Sclerosis

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    In this paper we propose a novel method for the segmentation of longitudinal brain MRI scans of patients suffering from Multiple Sclerosis. The method builds upon an existing cross-sectional method for simultaneous whole-brain and lesion segmentation, introducing subject-specific latent variables to encourage temporal consistency between longitudinal scans. It is very generally applicable, as it does not make any prior assumptions on the scanner, the MRI protocol, or the number and timing of longitudinal follow-up scans. Preliminary experiments on three longitudinal datasets indicate that the proposed method produces more reliable segmentations and detects disease effects better than the cross-sectional method it is based upon

    The Distribution of Toxoplasma gondii Cysts in the Brain of a Mouse with Latent Toxoplasmosis: Implications for the Behavioral Manipulation Hypothesis

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    reportedly manipulates rodent behavior to enhance the likelihood of transmission to its definitive cat host. The proximate mechanisms underlying this adaptive manipulation remain largely unclear, though a growing body of evidence suggests that the parasite-entrained dysregulation of dopamine metabolism plays a central role. Paradoxically, the distribution of the parasite in the brain has received only scant attention. at six months of age and examined 18 weeks later. The cysts were distributed throughout the brain and selective tropism of the parasite toward a particular functional system was not observed. Importantly, the cysts were not preferentially associated with the dopaminergic system and absent from the hypothalamic defensive system. The striking interindividual differences in the total parasite load and cyst distribution indicate a probabilistic nature of brain infestation. Still, some brain regions were consistently more infected than others. These included the olfactory bulb, the entorhinal, somatosensory, motor and orbital, frontal association and visual cortices, and, importantly, the hippocampus and the amygdala. By contrast, a consistently low incidence of tissue cysts was recorded in the cerebellum, the pontine nuclei, the caudate putamen and virtually all compact masses of myelinated axons. Numerous perivascular and leptomeningeal infiltrations of inflammatory cells were observed, but they were not associated with intracellular cysts. distribution stems from uneven brain colonization during acute infection and explains numerous behavioral abnormalities observed in the chronically infected rodents. Thus, the parasite can effectively change behavioral phenotype of infected hosts despite the absence of well targeted tropism
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