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  • 1
    Electronic Resource
    Electronic Resource
    Review of electrolytic conductance standards (1987)
    Springer
    Journal of solution chemistry 16 (1987), S. 985-997 
    Details
    ISSN: 1572-8927
    Keywords: Aqueous solution ; cell constant ; conductance ; electrolytic conductivity ; potassium chloride ; primary ; resistance ; resistivity, secondary, standards, and temperature scale
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Measurements of aqueous electrolytic conductance are performed routinely in a variety of disciplines and industries. Conductivity is a measure of the ionic content in solution and thus has applications in pharmaceuticals, power plants, rainwater, lake surveys, and oceanography, to name a few. A thorough review of the measurement of and standards for aqueous electrolytic conductance is herein presented. At present, the most precise and accurate standards have been set forth by the International Organization of Legal Metrology (OIML), and have been adopted by most other standards organizations. However, the uncertainty assigned to these standards, especially the secondary standards, is somewhat larger than would be expected from the physical aspects of the measurement. Several changes in the units and measurement scales, including temperature, volume, molar mass, resistance, and concentration obfuscate the accuracy of these standards. In addition to the review, research is proposed, using a conductance cell with variable length, to establish new standards for aqueous electrolytic conductance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00652583
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  • 2
    Electronic Resource
    Electronic Resource
    Determination of the absolute specific conductance of primary standard KCl solutions (1989)
    Springer
    Journal of solution chemistry 18 (1989), S. 515-528 
    Details
    ISSN: 1572-8927
    Keywords: Absolute standard ; conductivity cell ; demal ; electrolyte ; molality ; potassium chloride ; primary standard ; specific conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A determination of the absolute specific conductance of KCl solutions is demonstrated. The measurement is based on the conductance cell with a well defined geometry, having a difference in the removable center tube of accurately measured dimensions. The specific conductance of the solution is obtained from the measured resistances of the cell with and without the center tube and the measured l/A ratio of the center tube. Specific conductances obtained using the cell agree with the previously accepted standards for 0.1 demal and 0.01 demal solutions within 0.02%. Results are also presented for solutions based on molality. The temperature control, bridge, and detector technology used to obtain results of this accuracy are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00664234
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  • 3
    Electronic Resource
    Electronic Resource
    Absolute determination of electrolytic conductivity for primary standard KCl solutions from 0 to 50°C (1991)
    Springer
    Journal of solution chemistry 20 (1991), S. 391-401 
    Details
    ISSN: 1572-8927
    Keywords: Cell constant ; conductance ; demal ; electrolytic conductivity ; potassium chloride ; primary standards ; resistance ; specific conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An absolute determination of aqueous electrolytic conductivity has been made for primary standards 0.01D and 0.1D (demal) potassium chloride solutions over the temperature range of 0 to 50°C in 5 degree intervals. A cell with a removable center section of accurately known length and area was used for the measurements. Values were adjusted to be in conformity with the ITS-90 temperature scale. The overall uncertainty over the entire temperature range is estimated to be 0.03%. Values at 25°C for 0.01D and 0.1D KCl solutions are 0.0014086 and 0.012852 S-cm−1, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00650765
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  • 4
    Electronic Resource
    Electronic Resource
    The short- and long-term mechanical properties of filled and unfilled thermotropic liquid crystalline polymer injection moldings (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 48 (1993), S. 731-740 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    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 basic mechanical properties of a series of injection moldings of the thermotropic liquid crystalline polymer Vectra have been investigated to determine the effect of fillers on the short- and long-term mechanical properties of these materials. Mineral-filler addition results in a slight decrease in strength and an increase in stiffness in the flow direction, but has relatively little effect on the anisotropy. Glass fiber addition, on the other hand, may substantially lower the anisotropy depending on the degree of fiber orientation transverse to the flow direction. The glass fiber-filled grade investigated also showed improved creep properties at high temperature compared with both the unfilled and mineral-filled grades. © 1993 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070480415
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of an oxidative environment on the creep compliance of poly(ether urethane urea) (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 53 (1994), S. 1037-1049 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    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: Secondary creep of unstabilized poly(ether urethane urea) (PEUU) in an oxidative environment appears as a linear time-dependent component superimposed on the logarithmic, viscoelastic response. The surfaces of unstabilized PEUU crept in H2O2/CoCl2 have been characterized by scanning electron microscopy and ATR-FTIR. By examining PEUU crept for various periods of time, it is found that surface damage proceeds at gradually increasing size scales, culminating in large voids. It is hypothesized that the initial chain scission creates a flaw that grows in size under the influence of the applied load into a “nano-pit,” which grows further by coalescence into a pit and, finally, a void. The initial stages of voiding occur during an induction period when there is no measurable effect on the creep response. It is possible to estimate the average compliance of the damaged PEUU by assuming a composite model with an undamaged center layer sandwiched between damaged surface layers. When the contribution of the surface layers to the creep compliance is estimated from the creep curves, the average compliance of the damaged layer is found to be about 1.6 times higher than that of the undamaged PEUU. Independent calculations of the damaged layer compliance from the void fraction indicate that the damaged layer behaves as a flexible foam in the early stages, then as a more rigid foam at longer creep times. © 1994 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1994.070530806
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  • 6
    Electronic Resource
    Electronic Resource
    Complexes of starch polysaccharides and poly(ethylene co-acrylic acid): Structure and stability in solution (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 1701-1709 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    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: Chiroptical methods have been used to study the conformation and interactions of amylose and amylopectin with poly(ethylene co-acrylic acid) (EAA) in aqueous solution. These studies, along with X-ray diffraction and solid-state NMR data, show that amylose and EAA, as well as amylopectin and EAA, form helical V-type inclusion complexes when mixed in aqueous suspension. This structure apparently accounts for the partial compatibility observed in films containing starch and EAA. About 2/3 by weight of EAA does not interact with amylose and probably represents the ethylene-rich central core of the EAA micelle. EAA/amylose complexes in 10 mM NaOH were stable to temperatures 〉 90°C, whereas EAA/amylopectin complexes in the same solvent were largely disrupted at this temperature. Urea, at a concentration of 8 M, further destabilized both EAA/amylopectin and EAA/amylose complexes. Solutions with an alkaline pH (〉 9.5) dispersed EAA optimally and allowed maximum complexing with amylose. At pH values 〉 13, the EAA/amylose complexes were weaker, most likely due to electrostatic repulsion between ionized hydroxyl groups of amylose and carboxyl groups of EAA.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070420625
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  • 7
    Electronic Resource
    Electronic Resource
    An FTIR-ATR investigation of in vivo poly(ether urethane) degradation (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 46 (1992), S. 201-211 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    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: Surface degradation of implanted poly(ether urethane)s was studied quantitatively with a micro-ATR-FTIR technique. Substantial degradation was observed particularly in the soft segment at the α-carbon adjacent to the ether linkage. The degradation caused changes in the concentration profiles of the soft-segment groups in the depth direction, and the affected depth was up to 10 microns after implantation for 10 weeks. Inhibition of degradation by antioxidants indicated the oxidative nature of degradation. An in vivo poly(ether urethane) degradation mechanism was proposed.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070460202
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  • 8
    Electronic Resource
    Electronic Resource
    Treatment of leachate from a solid waste landfill site using a two-stage anaerobic filter (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 31 (1988), S. 257-266 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Raw leachate was treated using a two-stage upflow anaerobic filter process. Leachate from a solid waste landfill site, which received both municipal and industrial wastes, contained high organic matter (17-21 g/L COD, 13-14 g/L BOD, and 3.5-4.6 g/L volatile acids), and low metal (Zn and Fe) concentrations. Depending on sampling time, leachate composition and characteristics varied considerably. At an organic loading up to 4 g COD/day2 media area, the BOD and COD removal percentages were 98 and 91%, respectively. The biofilters were also effective for metal removal. However, the filter effluent contained a high concentration of ammonia. System overloading was characterized by the accumulation of large quantities of volatile acids and by a now ratio of alkalinity/volatile acids, resulting in low COD removal and reduced gas production. Once the first filter was upset, the second stage could only partially respond to the volatile acids accumulated in the effluent of first filter.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260310312
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  • 9
    Electronic Resource
    Electronic Resource
    Effects of interfacial instability on film boiling of saturated liquid helium I above a horizontal surface (1966)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 12 (1966), S. 238-244 
    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: Film boiling above a horizontal surface has been investigated theoretically and experimentally at standard gravity and 1 atm. Theoretical film boiling results for conventional fluids have been extended, on the basis of interfacial instability due to gravity, to include liquefied gases properties, such as low viscosity and small surface tension. In the experiments, primarily ordinary liquid helium I has been studied to extend the range of the film boiling Rayleigh numbers (based upon Laplace's reference length) from about 107 (reported for room temperature liquids) to values of the order of magnitude unity. The heat transfer data taken at surface excess temperatures ΔT (above the boiling point) between 80° and 300°K. have been correlated with a theoretical model which presumes the absence of any scaling length (Laplace length) associated with surface tension. At low ΔT the experimental results have been found to agree with a model which presumes a negligible influence of a scaling length due to surface tension and absence of detectable viscosity effects.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690120207
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  • 10
    Electronic Resource
    Electronic Resource
    Effect of some additives on the biostability of a poly(etherurethane) elastomer (1991)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 25 (1991), S. 725-739 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Four materials based on a single poly(etherurethane) (PEU) prepared from MDI and PTMEG but differing in additives were studied in the cage implant systm. The two additives studied were Santowhite powder at the 1% level and Methacrol 2138F 5%. Methacrol 2138F appeared to be immiscible with the base PEU and was dispersed in discrete domains about 0.5-μm in size. The retrieved PEU specimens were also cleaned and examined in the optical and scanning electron microscopes, and the size and density of adherent foreign body giant cells (FBGCs) were measured at implantation times up to 10 weeks. Methacrol 2138F had no effect on the density, coverage or size distribution of adherent FBGCs, but leaching of Methacrol 2138F was considered to be responsible for extensive pitting of the PEU surface. On the other hand, Santowhite powder appeared to inhibit formation of FBGCs, and while surface cracking and flaking were observed as early as 3 weeks postimplantation on some PEUs, the Santowhite powder effectively inhibited surface cracking and flaking up to the longest implantation time studied.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820250604
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