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  • Electronic Resource  (13)
  • Chemical Engineering  (8)
  • thermal conductivity  (3)
  • Column-switching  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Thermal conductivity of CVD diamond films (1996)
    Springer
    International journal of thermophysics 17 (1996), S. 695-703 
    Details
    ISSN: 1572-9567
    Keywords: AC calorimetry ; CVD diamond film ; Debye phonon model ; grain boundary ; thermal conductivity ; thermal diffusivity ; U-process
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Diamond films 60 and 170 µm in thickness were grown by PACVD (plasma-assisted chemical vapor deposition) under similar conditions. The thermal diffusivity of these freestanding films was measured between 100 and 300 K using AC calorimetry. Radiation heat loss from the surface was estimated by analyzing both the amplitude and the phase shift of a lock-in amplifier signal. Thermal conductivity was calculated using the specific heat data of natural diamond. At room temperature, the thermal conductivity of the 60 and 170 υm films is 9 and 16 W-cm−1. K−1 respectively, which is 40–70% that of natural diamond, The temperature dependence of thermal conductivity of the CVD diamond films is similar to that of natural diamond, Phonon scattering processes are considered using the Debye model, The microsize of the grain boundary has a significant effect on the mean free path of phonons at low temperatures. The grain in CVD diamond film is grown as a columnar structure, Thus, the thicker film has the larger mean grain size and the higher thermal conductivity. Scanning electron microscopy (SEM) and Raman spectroscopy were used to study the microstructure of the CVD diamond films. In this experiment, we evaluated the quality of CVD diamond film of the whole sample by measuring the thermal conductivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01441515
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  • 2
    Electronic Resource
    Electronic Resource
    Thermal conductivity of R32 and its mixture with R134a (1995)
    Springer
    International journal of thermophysics 16 (1995), S. 1193-1201 
    Details
    ISSN: 1572-9567
    Keywords: R134a, R32 ; R32+R134a mixture ; thermal conductivity ; transient hot-wire method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The liquid thermal conductivity of R32 (CH2F2) and R134a (CF3CH2F) was measured in the range from 223 to 323 K and from 2 to 20 MPa by the transient hot-wire method. The thermal conductivity of the R32+R134a mixture was also measured in the same range by varying the mass fraction of R32. The measured data are analyzed to obtain a correlation in terms of temperature, pressure and composition of the mixture. The uncertainty of our measurements is estimated to be within ±2%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02081287
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  • 3
    Electronic Resource
    Electronic Resource
    Measurement of the Thermal Conductivity of Si and GaAs Wafers Using the Photothermal Displacement Technique (1998)
    Springer
    International journal of thermophysics 19 (1998), S. 281-290 
    Details
    ISSN: 1572-9567
    Keywords: GaAs ; impurities ; phonons ; photothermal displacement technique ; semiconductors ; Si ; thermal conductivity ; thermal diffusivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Thermal conductivity and thermal diffusivity of Si and GaAs wafers were measured using the photothermal displacement technique, and the temperature dependence of these two quantities was investigated. Thermal diffusivity was obtained from the phase difference between the heating source and the signal, and thermal conductivity was determined from the maximum value of the signal amplitude in the temperature range 80 to 300 K. It was verified that an increase in doping concentration gives rise to a decrease in thermal conductivity at low temperatures. The experimental results obtained on samples with different types and doping concentrations are consistent with those expected from theoretical considerations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021467606454
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  • 4
    Electronic Resource
    Electronic Resource
    Analysis of reaction injection molding process of polyurethane-unsaturated polyester blends. Part II: Mechanical properties (1987)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987), S. 1252-1257 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The mechanical properties of polyurethane-unsaturated polyester interpenetrating polymer networks (IPNs) that were prepared by reaction injection molding (RIM) process were measured with variations In composition, cross-link density, and relative reaction rate. From dynamic mechanical analysis (DMA), it was found that the two component polymers had a good compatibility over the whole composition range. The tensile strengths of the blends were greater than those of the pure components and had a maximum value at 50/50 composition. The modulus of elasticity and surface hardness decreased and the impact strength increased as the polyurethane content was increased, but the changes were not high at low polyurethane content, below 50%. For higher cross-link density, the compatibility was enhanced and the mechanical properties were improved. When the reaction rates of the components were different, some extent of phase separation was found in DMA and the properties were affected adversely.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760271608
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  • 5
    Electronic Resource
    Electronic Resource
    Simultaneous determination of parathion and metabolites in serum by HPLC with column switching (1997)
    Springer
    Chromatographia 44 (1997), S. 473-476 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Column-switching ; Parathion, and metabolites in serum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new high-performance liquid chromatographic method with column-switching has been developed for the simultaneous determination of parathion and its metabolites such asp-nitrophenol and paraoxon in serum. Serum samples were injected onto a precolumn packed with LiChroprep RP-8 after simple dilution with 20% phosphoric acid. Polar plasma components were washed with 0.02 M phosphate buffer (pH 3.0). After valve switching, the concentrated compounds were eluted in back-flush mode and separated on a Ultracarb ODS 30 column with a gradient of acetonitrile −0.01 M phosphate buffer (pH 3.0) as mobile phase. The method showed excellent precision, accuracy and speed with detection limit of 0.1 μg mL−1. Total analysis time per sample was 〈40 min and coefficients of variation for intra-and inter-assay were 〈4.5%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02466739
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  • 6
    Electronic Resource
    Electronic Resource
    Determination of myristicin in rat serum samples using microbore high performance liquid chromatography with column-switching (1998)
    Springer
    Chromatographia 48 (1998), S. 365-368 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Microbore columns ; Column-switching ; Myristicin ; Serum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A microbore high-performance liquid chromatographic method with column-switching was developed for the analysis of myristicin from rat serum without prepurification. Deproteinization, fractionation, concentration and separation of analyte were carried out by appropriate switching of columns and using solvent mixtures. The method showed excellent precision, accuracy and speed with a detection limit of 10 ng mL−1 from 25 μL of serum. The total analysis time per sample was 25 min and the coefficients of variation for intra- and inter-assay were less than 1.8%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02467705
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  • 7
    Electronic Resource
    Electronic Resource
    Pressure drop for cocurrent downflow of gas-solids suspensions (1983)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 29 (1983), S. 353-360 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Pressure drop for a gas-solids suspension flowing concurrently downward in a 13-mm inside-diameter tube was investigated using 329-micron spherical glass beads in air. The gas Reynolds number varied from 0 to 30,000 with solids-loading ratios of up to 20 at a gas Reynolds number of 10,000. The frictional pressure drop for downflow was found to be a weaker function of the solids-loading ratio than the upflow case using data reported in the literature. Empirical correlation of the two-phase friction factor, in terms of the gas Reynolds number and a dimensionless parameter, CDEPD/[(1 - Ep)dp], showed that at high solids loadings, particles tend to stabilize the suspension flow. The dimensionless parameter seems to be applicable to a universal pressure drop correlation for solids-fluid systems, but requires further investigation.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690290302
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  • 8
    Electronic Resource
    Electronic Resource
    Heat transfer to gas-solids suspensions flowing cocurrently downward in a circular tube (1983)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 29 (1983), S. 306-312 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Heat transfer to a gas-solids suspension flowing cocurrently downward in a 13-mm inside diameter tube with uniform heat-flux boundary conditions was investigated using 329-μm spherical glass beads in air. The gas Reynolds number varied from 0 to 30,000 with solids-loading ratios of up to 20 at a gas Reynolds number of 10,000. The suspension Nusselt number, defined in terms of the wall-to-gas mixed-mean temperature difference, decreased with increasing solids-loading ratio at high Reynolds numbers, while it changed little from the value for gas alone at low Reynolds numbers. A possible explanation is given by considering the effects of particles on the fluid mechanical properties of the gas. Asymptotic Nusselt numbers in downflow are compared with results of other investigations for upflow.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690290219
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  • 9
    Electronic Resource
    Electronic Resource
    Phase behavior of blends of poly(vinyl chloride) with an α-methyl styrene/acrylonitrile copolymer (1989)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 29 (1989), S. 581-585 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Poly(vinyl chloride), PVC, is shown to be miscible with an α-methyl styrene/acrylonitrile copolymer, αMSAN, containing 30 percent AN by weight using differential scanning calorimetry for blends prepared by several methods. Melt blending gave single Tg mixtures; whereas, solution techniques gave results that depended on the solvent choice and the manner in which it was removed. These blends do not phase separate on heating prior to significant PVC decomposition (∼250°C) in contrast to PVC/SAN blends which have much lower cloud points. Repulsion between α-methyl styrene and acrylonitrile units in the copolymer is the principal cause for miscibility of this system as shown by an analysis based on a binary interaction model using calorimetry data for low molecular weight liquid analog compounds.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760290903
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  • 10
    Electronic Resource
    Electronic Resource
    Reaction mechanisms of polyacrylonitrile on thermal treatment (1993)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 33 (1993), S. 1452-1457 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A high-temperature radical scavenger, 2,2-diphenyl-l-picryl hydrazyl (DPPH), has been used to study the reaction mechanisms of polyacrylonitrile (PAN) on thermal treatment. The effect of DPPH on the cyclization reaction of PAN in both air and nitrogen, investigated by differential scanning calorimetry (DSC), helped to verify the proposed reaction mechanisms, i.e., the free radical and the ionic ones. For PAN homopolymer, the peak temperature of the reaction exotherm shifted to higher temperatures and the heat of reaction was decreased with increasing DPPH concentration. For PAN copolymer with methylacrylate and itaconic acid, however, the effects of DPPH on DSC thermograms were insignificant. The effects of IPPH suggest that the reaction of the nitrile groups proceeds by free radicals for the homopolymer while by ions for the copolymer. The activation energies for the thermal reactions of PAN in both air and nitrogen were also estimated by the dynamic DSC method, and they proved to be highly dependent on reaction mechanism, environment of thermal treatment, and DPPH concentration.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760332203
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