ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    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: Thermal analysis of oriented polymers involves several transitional processes which may be coupled in a complex way. The disorientation process that occurs during heating is often accompanied by dimensional shrinkage which may occur in both amorphous and crystalline oriented polymers. From differential scanning calorimetry (DSC) measurements it has been determined that shrinkage is an exothermic process. In amorphous atactic polystyrene (PS), hot drawn uniaxially, the shrinkage occurs just above Tg. In triaxially oriented polyethylene (PE) and isotactic polypropylene (iPP), shrinkage and melting take place concomitantly, producing multiple melting peaks. In rolltruded (and also in biaxially oriented) poly(ethyleneterephthalate) (PET) films, shrinkage and crystallization are found to be coupled and to occur between Tg and Tm upon heating. If the enthalpy contribution due to shrinkage is ignored, it follows that crystallinities determined by DSC are incorrect. In this study, the influence of shrinkage upon transitional changes in oriented polymers is investigated in a systematic manner.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 27 (1989), S. 65-72 
    ISSN: 0887-6258
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 29 (1989), S. 715-721 
    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 effect of rolltrusion, a solid state deformation process, on the three dimensional mechanical properties of several polymers has been measured. Polymers studied included isotactic polypropylene (iPP), polyvinylidene fluoride (PVDF), and propylene/ethylene block copolymers. It was found that mechanical strength is enhanced triaxially for all these specimens upon rolltrusion. Material stiffness also exhibits 3-D improvement, depending on the polymer type and processing conditions. These new results are discussed in regard to some structural models in the literature.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 50 (1993), S. 353-365 
    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: Chitosan was chemically modified by alkylation with N-(2-bromoethyl) phthalimide, N-(3-bromopropyl) phthalimide, and N-(4-bromobutyl) phthalimide. The resulting N-(phthalidimidoalkyl) chitosans were treated with hydrazine to remove the phthalidimido group resulting in the final N-(aminoalkyl) chitosan products. For comparison purposes, poly(vinyl alcohol) (PVA) was alkylated with N-(3-bromopropyl) phthalimide, then treated with hydrazine to give the N-(3-aminopropyl) PVA product. All alkylation products were characterized by solution 1H- and 13C-NMR and by solid-state CP-MAS 13C-NMR. The above synthetic polymer derivatives, as well as chitosan, polyallyl amine, and polyethylen-imine, were used to form membrane coatings around calcium alginate beads in which blue dextran of molecular weight 7.08×104 or 26.6×104 was entrapped. These microcapsules were prepared by extrusion of a solution of blue dextran in sodium alginate into a solution containing calcium chloride and the membrane polymer. Membrane integrity and permeability were assessed by measuring the elution of the blue dextran from the capsules, spectrophotometrically. © 1993 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 30 (1990), S. 635-643 
    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: Rolltrusion, a single step solid state deformation process, has been successfully applied to isotactic poly(propylene), iPP, to produce unique 3-D properties. Mechanical property enhancement not only occurs in the principal draw direction, but also in the transverse directions. A systematic series of standard (ASTM) tensile and compressive experiments were made on well oriented materials supporting this claim. Tensile testing was also performed on dumb-bell shaped specimens cut at various angles to the main deformation direction. A variety of observations were made during testing. Deformation bands, anisotropic yielding, and ductile-to-brittle behavior were observed. These results are presented along with a morphological model that has been developed to account for the behavior of these unique triaxially oriented polymers.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 34 (1987), S. 2337-2343 
    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
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 21 (1983), S. 335-340 
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2011-08-24
    Description: Cavitation of the oil film in a dynamically loaded journal bearing was studied using high-speed photography and pressure measurement simultaneously. Comparison of the visual and pressure data provided considerable insight into the occurence and non-occurrence of cavitation. It was found that (1), cavitation typically occurred in the form of one bubble with the pressure in the cavitation bubble close to the absolute zero; and (2), for cavitation-producing operating conditions, cavitation did not always occur; with the oil film then supporting a tensile stress.
    Keywords: MECHANICAL ENGINEERING
    Type: ASME, Transactions, Journal of Tribology (ISSN 0742-4787); p. 88-95.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2011-08-24
    Description: Two formulas, one for the characteristic time of filling a void with the vapor of the surrounding liquid, and one of filling the void by diffusion of the dissolved gas in the liquid, are derived. By comparing these time scales with that of the dynamic operation of oil film bearings, it is concluded that the evaporation process is usually fast enough to fill the cavitation bubble with oil vapor; whereas the diffusion process is much too slow for the dissolved air to liberate itself and enter the cavitation bubble. These results imply that the formation of a two phase fluid in dynamically loaded bearings, as often reported in the literature, is caused by air entrainment. They further indicate a way to simplify the treatment of the dynamic problem of bubble evolution.
    Keywords: MECHANICAL ENGINEERING
    Type: ASME, Transactions, Journal of Tribology (ISSN 0742-4787); 114; 3, Ju
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2019-06-28
    Description: The geometrical parameters for a wormgear intended to be used as the transmission in advanced helicopters are finalized. The resulting contact pattern of the meshing tooth surfaces is suitable for the implementation of hydrostatic lubrication Fluid film lubrication of the contact is formulated considering external pressurization as well as hydrodynamic wedge and squeeze actions. The lubrication analysis is aimed at obtaining the oil supply pressure needed to separate the worm and gear surfaces by a prescribed minimum film thickness. The procedure of solving the mathematical problem is outlined.
    Keywords: MECHANICAL ENGINEERING
    Type: AD-A290331 , ARL-CR-219 , E-9345 , NAS 1.26:195416 , NASA-CR-195416
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...