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
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Growth and change 4 (1973), S. 0 
    ISSN: 1468-2257
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography , Economics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Growth and change 7 (1976), S. 0 
    ISSN: 1468-2257
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography , Economics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Growth and change 7 (1976), S. 0 
    ISSN: 1468-2257
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography , Economics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of polymer research 3 (1996), S. 105-114 
    ISSN: 1572-8935
    Keywords: Aromatic polyamide ; Poly(m-phenylene isophthalamide) ; PmIA-PU copolymers ; Conventional polyurethane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract In this study,we modified two kinds of conventional polyurethane (PU) by the low molecular weight diamine-terminated wholly-rigid aromatic polyamide poly(m-phenylene isophthalamide) (PmIA) (Nomex). Two molecular weights (1000 and 2000) of poly(tetramethylene glycol) (PTMG) with 4,4′-diphenylene methane diisocyanate (MDI) and with three different ratios of low molecular weight diamine-terminated PmIA prepolymer with different molecular weight of 346, 584, 823 were synthesized to form six PmIA-PU block copolymers. Various block copolymers were also obtained by different ratios of wholly-rigid PmIA prepolymers. Inherent viscosity results indicated that the block copolymers are more viscous than conventional polyurethanes, suggesting that the block copolymers had sufficiently high molecular weights. Moreover, results obtained from differential scanning calorimetry (DSC) and dynamic mechanical properties analysis (DMA) demonstrated that the block copolymers not only exhibited a glass transition temperature (Tg) under 0 °C, but also had a higher storage modulus (E′) than those of the conventional PU. Opitical microscopy (OM), phase contrast microscopy (PCM), and transmission electron microscopy (TEM) analyses confirmed that all of the block copolymers had a dispersed phase structure. The mechanical properties, tensile strength and 300% modulus of the block copolymers were found to be better than those of conventional PU.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-0495
    Keywords: Key words Agricultural production ; Agriculture and the environment ; Soil nitrogen tests ; Technological change
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  The economic and environmental consequences of soil nitrogen tests can have significant impacts on agricultural production. Some of these are explored here. The pre-side-dress soil N-test is evaluated for a hypothetical farmer growing corn at the ARS Sustainable Agriculture Demonstration Farm site in southern Maryland. For a farmer not currently using a soil N-test, adoption of this technology can lead to the enhancement of net farm income and the reduction in nitrogen loss to the environment. This will transpire only if the farmer is currently underestimating nitrogen carryover by more than 25% or applying nitrogen fertilizer based solely on an expected plateau-yield goal.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 29 (1994), S. 2040-2052 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Nylon-6 was reinforced by two semi-rigid aromatic polyamides, poly(p-diphenylmethyl terephthalamide) (PMA), and poly(p-diphenyloxide terephthalamide) (POA), and also one wholly-rigid aromatic polyamide, poly(m-phenylene isophthalamide) (PmlA) by physical blending and chemical copolymerization usingp-amino phenyl acetic acid (P-APA) as a coupling agent. From the results of differential scanning-calorimetry, it was shown that both the polyblends with semi-rigid and wholly-rigid polyamides exhibited a glass transition temperature,Tg, higher than that of nylon-6 homopolymer. It also showed that theT gs of wholly-rigid polyblends were higher than those of semi-rigid polyblends. Nevertheless, the multiblock copolyamides appeared to have even higherT g andT m, and better thermal stability. Morphological observations revealed that all the polymer alloys (polyblends and copolymers) were a dispersed phase structure, although the multiblock copolyamides were more homogeneous and compatible. Based on wide-angle X-ray diffraction, it was found that the polyblends had two diffraction peaks, i.e. 2θ = 20.5 ° and 24 °. However, the multiblock copolyamides had only one peak at 2θ = 20 °, evidently indicating a new crystal structure of the multiblock copolyamides formed. For the mechanical properties, it was found that the multiblock copolyamides had a more significant reinforcing effect than those of polyblends, especially those copolymerizing with wholly aromatic polyamides.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 30 (1995), S. 824-833 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Flexible polyurethane (PU) was reinforced by wholly-rigid aromatic polyamide poly (m-phenylene isophthalamide) (PmlA) (Nomex) by physical polyblending and chemical copolymerization. Three polyurethane elastomers were blended physically with various amounts of high molecular weight Nomex to form twelve PU/Nomex polyblends in order to modify their physical properties. Also three multiblock copolyamides (PU-Nomex)were synthesised with a low molecular weight diamine-terminated Nomex prepolymer as a hydrogen donor for chain extending. From differential scanning calorimetry and Rheovibron measurements it was shown that both the polyblends and multiblock copolyamides exhibited a glass transition temperature under 0 °C and had a higher storage modulus, E′, than those of the polyurethane. Scanning electron microscopy revealed that the polyblends and multiblock copolyamides had a dispersed phase structure. From the wide-angle X-ray diffraction pattern of the polyurethane and multiblock copolyamides it was found that the degree of stress-induced crystallization was dependent on the composition of the soft and hard segments and also the degree of its stretching. With regard to mechanical properties, it was found that both the tensile strength and elongation of the multiblock copolyamides had a more significant reinforcing effect than those of the polyblends and polyurethanes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 12 (1993), S. 1781-1785 
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 28 (1993), S. 4862-4867 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Reinforcement of flexible nylon-6 by using poly (m-phenylene isophthalamide) PmIA (Nomex) using (MDI) 4,4′-diphenylene methane diisocyanate as a chain extender was studied. Observation by scanning electron microscopy showed that the multiblock copolymer had a homogeneous texture. From the differential scanning calorimetry measurements, the multiblock copolymers were shown to have only one melting point, T m, which is higher than that of nylon-6. The wide-angle X-ray diffraction pattern shows that nylon-6 has two diffraction peaks at 2θ=20° and 23.8°. However, the multiblock copolymer has only one peak at 2θ=20°, indicating a different crystal structure of multiblock copolymers. The copolymers appear to have a significant reinforcing effect on the mechanical properties.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 29 (1994), S. 1179-1184 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In this study, the flexible nylon-6 was reinforced by the semi-rigid aromatic polyamide poly(p-diphenylmethyl terephthalamide) through chemical copolymerization using p-aminophenylacetic acid as a coupling agent. From differential scanning calorimetry it was discovered that theT g andT m of multiblock copolyamides were higher than those of triblock copolyamides. From observation by scanning electron microscopy the multiblock copolyamides exhibited a homogeneous texture rather than an aggregated one. We found that in wide-angle X-ray diffraction patterns the triblock copolyamides had two diffraction peaks, i.e. 2θ=20 and 24
    Type of Medium: Electronic Resource
    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...