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  • 1990-1994  (3)
  • 1985-1989  (6)
  • Polymer and Materials Science  (6)
  • Blasting  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Geotechnical and geological engineering 7 (1989), S. 301-313 
    ISSN: 1573-1529
    Keywords: Blasting ; cast blasting ; dam construction ; caving blast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Summary A proposal is under consideration to construct a dam on an experimental basis by a cast (or directional) blasting technique, ‘DBT’. The dam site is located at Bharari Khad, a tributary of the Sutlaz river in Himachal Pradesh. Site investigations have been completed and a large scale blast has been designed for construction of the experimental dam. The paper describes the basic design concept of DBT and application of ‘throw’ and ‘caving’ methods for construction of dams. The preliminary tests required to design the blasting pattern are detailed. The technique has a great potential because it reduces construction cost and time particularly in inaccessible mountain regions.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Geotechnical and geological engineering 7 (1989), S. 333-340 
    ISSN: 1573-1529
    Keywords: Blasting ; fragmentation ; natural blocks ; surface mining ; quarrying
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 30 (1985), S. 2821-2836 
    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 physical properties of a new class of ionomers comprising a semirigid polyphenylene ether backbone were investigated. The material was studied principally in the form of films of ca. 150 μm micrometers in thickness. The study focused on material of 600 equivalent weight. Torsion pendulum results showed a significant increase in the glass transition temperature of the ionomer relative to that of its ester precursor but gave no evidence of ionic clustering. Stress-strain studies performed both in water and in 20% KOH solution at 80°C indicated that the mechanical properties of the material remain stable under these conditions. Differential scanning calorimetry was used to investigate both the high temperature behavior and the water uptake of the ionomer films. The behavior of this ionomer at high temperature and in an alkaline solution is of particular interest in view of the possible use of these films as separators in an alkaline electrolysis cell.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 35 (1988), S. 1459-1472 
    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 effect of polymer morphology on the dielectric breakdown of isotactic polypropylene was investigated under the influence of a ramped ac voltage. Samples were prepared by melt-pressing polypropylene beads into plaques and subsequently quenching or isothermally cyrstallizing these plaques. Some of the quenched samples were annealed at different temperatures to induce further crystallinity. The plaques were then characterized by wide-angle X-ray diffraction, density measurements, and differential scanning calorimetry. The 60 Hz, ac breakdown voltages of the samples were determined at 7°C, 23°C, and 45°C in a specially designed test cell. There was a lack of any significant effect on the ac breakdown strength of isotactic polypropylene of either the overall crystallinity or the crystallite thickness. This result can be understood in light of previous studies relating the electrical breakdown of polymers to morphology. It is postulated that the degree of crystallinity would influence the breakdown characteristics only when the amorphous regions constitute a small fraction of the total volume, that is, at very high crystallinity values - values beyond the range of the present study.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Geotechnical and geological engineering 7 (1989), S. 239-248 
    ISSN: 1573-1529
    Keywords: Blasting ; rock fragmentation ; rock discontinuities ; surface mining ; quarrying
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 29 (1990), S. 347-355 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Light scattering has been used to investigate the structure of human tracheobronchial mucin glycoproteins (HTBM) from the sputum of cystic fibrosis patients. The specimen was extracted using 6M guanidinium hydrochloride solution and fractionated by gel exclusion chromatography on Sephacryl S-1000. The fractionated HTBM was purified by density gradient ultracentrifugation. Purity of the resulting material was confirmed by SDS polyacrylamide gel electrophoresis and uv spectroscopy. Light scattering measurements on the fractionated mucins yield weight-average molecular weights Mw, and z-average radii of gyration Rg, z. The native cystic fibrosis HTBM consisted of a high molecular weight fraction with Mw = 9.3 × 106 daltons and a lower molecular weight fraction contanining partly degraded mucins. After reduction and carboxymethylation of the high molecular weight native fraction, the resulting material was separated into three pools with Mw values of 5.1 × 106, 1.6 × 106, and 400,000. The derived molecular weights for the protein cores Mp,w, and the experimental radii of gyration are found to be consistent with the Mp,w - Rg relation established previously for submaxillary, cervical, and gastric mucins. These results imply that HTBM has the same extended-coil conformation reported for other mucins and has a molecular structure consisting of subunits, linked into linear chains via covalent (disulfide) bonds.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 43 (1991), S. 1293-1299 
    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 individual, competitive, and displacement adsorption of polyvinyl alcohol (PVOH), hydroxyethyl cellulose (HEC), and hydroxypropylmethyl cellulose (HPMC) in aqueous solution onto an attapulgite clay has been systematically studied. For the individual adsorption experiments, the amount of polymer adsorbed at equilibrium decreased in the order PVOH, HEC, HPMC. In the competitive adsorption experiments, the adsorption level of each polymer is diminished by the presence of a competing polymeric species. Binary mixtures of a cellulosic polymer (HEC or HPMC) with PVOH result in a substantial reduction in the amount of cellulosic polymer adsorbed. In the displacement adsorption studies, the sequential addition of HEC or HPMC is not able to displace previously adsorbed PVOH molecules to any appreciable extent. However, the addition of PVOH to previously equilibrated HEC/clay or HPMC/clay suspensions results in a large amount of the adsorbed cellulosic polymer being displaced by PVOH, especially under conditions of high surface coverage. These results indicate that PVOH is preferentially adsorbed on the clay surface and the strength of attachment to the surface is greater for PVOH than for either cellulosic polymer.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 49 (1993), S. 1131-1144 
    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 structural properties of epoxy can be retained and thermal stability improved by blending epoxy with bismaleimide (BMI) and curing them simultaneously. Depending on the curing agent, the overall viscoelastic properties of the cured material can be varied. In the present work, diaminodiphenylmethane and diaminodiphenyl sulfone have been used as curing agents to prepare blends of epoxy and BMI. The blends were characterized by DSC, TG, DMA, and SEM. Results indicate that an excellent interpenetrating network forms in both the cases and that the DDM-cured system gives better thermal stability than that of the DDS-cured system. © 1993 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 30 (1985), S. 2837-2846 
    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 sorption and transport properties of newly developed aromatic carboxylate polymers have been investigated in the context of their application as membrane separators for water electrolyzers. Conductance measurements of aromatic carboxylates of various equivalent weights have been performed as a function of current density, temperature, and electrolyte environment. Results have been compared with those for Nafion 117. The sorption results in dilute and concentrated solution show large water and electrolyte uptake for the aromatic carboxylate films. Furthermore, relatively large sodium ion self-diffusion coefficients have been found in both dilute and concentrated solution environments. The results of these measurements are characteristic of microporous films. The de conductance behavior of the aromatic carboxylate ionomers is quite different from that found for nonporous 1150 equivalent weight Nafion membranes. This difference is caused primarily by the microporous structure of the aromatic carboxylates, which results in large membrane specific conductances.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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