5,059 research outputs found

    Thermal conductivity, electrical resistivity, and thermopower of aerospace alloys from 4 to 300 K. 6: Fe-22Cr-13Ni-5Mn stainless steel

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    The equipment and techniques for determining the thermal conductivity, electrical resistivity Lorenz ratio, and thermopower characteristics of Fe-22Cr-13Ni-5Mn stainless steel are discussed. The dimensions of the specimen and its preparation are described. The experimental data are represented by arbitrary functions over the entire range and smooth tables are generated from these functions

    Thermal conductivity of austenitic stainless steel, SRM 735, from 5 to 280 K

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    Thermal conductivity and electrical resistivity measurements were conducted on two lots of an austenitic stainless steel. Electrical resistivity measurements were performed on the second lot, both before and after the material was hot-swaged and reannealed to a size 1/10 the original diameter. These measurements indicate that this steel can be swaged and reannealed without an appreciable change in thermal conductivity. Electrical resistivity measurements as well as direct thermal conductivity measurements on several specimens from both lots indicate a material variability in these lots of less than 1% in thermal conductivity

    Thermal conductivity, electrical resistivity, and thermopower of aerospace alloys from 4 to 300 K. 3: Annealed Inconel 718

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    Determination of thermal conductivity, electrical resistivity, Lorentz ratio, and thermopower for annealed specimen of Inconel 718 at temperatures from 4 to 300

    Standard reference materials: Thermal conductivity of electrolytic iron, SRM 734, from 4 to 300 K

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    Thermal conductivity data were obtained by the axial one-dimensional heat flow method for a cylindrical rod 3.6 mm in diameter and 23 cm long with an electric heater at one end and a temperature controlled sink at the other. Variability of this iron was studied by means of electrical residual resistivity ratio measurements on 63 specimens. This study showed that with a two-hour anneal at 1000 C one can obtain a thermal conductivity Standard Reference Material that has variability of less than 1% in thermal conductivity

    Cryogenic thermocouple calibration tables

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    Thermocouple calibration standards are developed for low-temperature thermocouple materials. Thermovoltage, thermopower, and the thermopower derivative are presented in tabular and graphical form

    Cryogenic thermocouple tables

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    Cryogenic standardized thermocouple materials table

    Morphology of the Nuclear Disk in M87

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    A deep, fuly sampled diffraction limited (FWHM ~ 70 mas) narrow-band image of the central region in M87 was obtained with the Wide Filed and Planetary Camera 2 of the Hubble Space Telescope using the dithering technique. The H-alpha+[NII] continuum subtracted image reveals a wealth of details in the gaseous disk structure described earlier by Ford et al. (1994). The disk morphology is dominated by a well defined three-arm spiral pattern. In addition, the major spiral arms contain a large number of small "arclets" covering a range of sizes (0.1-0.3 arcsec = 10-30 pc). The overall surface brightness profile inside a radius ~1.5" (100 pc) is well represented by a power-law I(mu) ~ mu^(-1.75), but when the central ~40 pc are excluded it can be equally well fit by an exponential disk. The major axis position angle remains constant at about PA_disk ~ 6 deg for the innermost ~1", implying the disk is oriented nearly perpendicular to the synchrotron jet (PA_jet ~ 291 deg). At larger radial distances the isophotes twist, reflecting the gas distribution in the filaments connecting to the disk outskirts. The ellipticity within the same radial range is e = 0.2-0.4, which implies an inclination angle of i~35 deg. The sense of rotation combined with the dust obscuration pattern indicate that the spiral arms are trailing.Comment: 5 pages, 3 postscript figures, to appear in the Proceedings of the M87 Workshop, Ringberg castle, Germany, 15-19 Sep 1997, also available from http://jhufos.pha.jhu.edu/~zlatan/papers.htm

    Seasonal and Regional Animal Use of Drainage Structures to Cross Under Roadways

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    Road drainage structures, hereafter designated culverts, are often used by wildlife and other animals to cross under roadways. However, crossings may vary by species, culvert design, different environmental factors, and land-use and land-cover (LULC) at culvert sites. We monitored 265 culverts located throughout Maryland, USA, with motion-detecting game cameras to assess seasonal and regional effects on culvert crossing rates by wildlife and other animal species considered common to the areas. Northern raccoon (Procyon lotor) and Virginia opossum (Didelphis virginiana) exhibited lower crossing rates in culverts during winter than at other times of the year. We did not detect any difference in seasonal crossings for other species, but several species exhibited similar patterns of lower crossings/culvert/day during winter. We detected more crossings/culvert/day in the Piedmont ecoregion of Maryland for several species associated with farmland and suburbia (e.g., raccoon and red fox [Vulpes vulpes]). In contrast, opossum and free-ranging domestic cat (Felis catus) crossing rates were greater in the Appalachian Mountain ecoregion. The crossing rates for the only bird species we recorded on camera traps, the great blue heron (Ardea herodias), tended to increase from west to east, with its highest crossing rate on the Eastern Shore (lower coastal plain) of Maryland, where these birds are known to be abundant in tidal marshes. Besides a myriad of LULC and structural variables known to affect wildlife and other animal crossing rates, seasonal and regional differences in animal use must also be taken into consideration for culvert design and placement or retrofitting existing culverts to enhance crossings by particular animal species

    Cryogenic thermocouple tables. Part 3 - Miscellaneous and comparison material combinations

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    Graphs and tables of thermocouples of Chromel, copper, platinum, and silver vs gol

    Cloning and expression of a human kinesin heavy chain gene: interaction of the COOH-terminal domain with cytoplasmic microtubules in transfected CV-1 cells.

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    To understand the interactions between the microtubule-based motor protein kinesin and intracellular components, we have expressed the kinesin heavy chain and its different domains in CV-1 monkey kidney epithelial cells and examined their distributions by immunofluorescence microscopy. For this study, we cloned and sequenced cDNAs encoding a kinesin heavy chain from a human placental library. The human kinesin heavy chain exhibits a high level of sequence identity to the previously cloned invertebrate kinesin heavy chains; homologies between the COOH-terminal domain of human and invertebrate kinesins and the nonmotor domain of the Aspergillus kinesin-like protein bimC were also found. The gene encoding the human kinesin heavy chain also contains a small upstream open reading frame in a G-C rich 5' untranslated region, features that are associated with translational regulation in certain mRNAs. After transient expression in CV-1 cells, the kinesin heavy chain showed both a diffuse distribution and a filamentous staining pattern that coaligned with microtubules but not vimentin intermediate filaments. Altering the number and distribution of microtubules with taxol or nocodazole produced corresponding changes in the localization of the expressed kinesin heavy chain. The expressed NH2-terminal motor and the COOH-terminal tail domains, but not the alpha-helical coiled coil rod domain, also colocalized with microtubules. The finding that both the kinesin motor and tail domains can interact with cytoplasmic microtubules raises the possibility that kinesin could crossbridge and induce sliding between microtubules under certain circumstances
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