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  • 1
    ISSN: 1436-722X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract  The combination of synthetic thermoplastic polymers and wood is normally problematic because wood surfaces are hydrophilic while typical thermoplastic polymers are hydrophobic. A possible solution is to use block copolymer coupling agents. In this work we show the use of a potentially useful synthetic method of producing hydrophilic-hydrophobic block copolymers as hydrophobic coatings and coupling agents in polystyrene/wood flour composites. In particular, wood veneers are coated with water-based emulsions of hydrophilic-hydrophobic block copolymers from styrene and methacrylic acid. Dried coated surfaces are shown to become hydrophobic through dynamic contact angle measurements. When wood flour is coated with the hydrophilic-hydrophobic block copolymer based on styrene and acrylic acid, significant improvement in the ultimate tensile properties of composites formed from coated wood flour/polystyrene mixtures is realized. Since no volatile organic compounds (VOCs) are used in coating wood surfaces and subsequent composite production, improvement in mechanical properties of thermoplastic/wood flour composites are shown to occur in environmentally responsible formulations.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of inorganic and organometallic polymers and materials 1 (1991), S. 167-187 
    ISSN: 1572-8870
    Keywords: Hybrid CERAMER ; sol gel ; network polymers ; titanium tetraisopropoxide ; zirconium tetra-n-propoxide poly(tetramethylene oxide) ; tetraethylorthosilicate ; stress-elongation response
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The structure-property relationships are presented for two new organic/inorganic hybrid network systems which were prepared by the sol gel method using either titanium tetraisopropoxide or zirconium tetra-n-propoxide with silane end-capped poly(tetramethylene oxide) (PTMO) oligomers. These novel network materials, broadly referred to as CERAMERs, are optically transparent and monolithic in form, as were CERAMERs prepared with PTMO and tetraethylorthosilicate (TEOS) as the metal alkoxide in the sol gel process. The dynamic mechanical behavior of the titanium- and zirconium-containing CERAMERs exhibit similar trends as reported for the TEOS/PTMO CERAMERs. The stress-elongation response, however, exhibits yielding behavior and higher moduli and ultimate stress at break. The small-angle X-ray scattering (SAXS) behavior of these materials indicates a morphology similar to that measured in other CERAMERs prepared previously. A morphological model developed for these novel hybrid materials is described. Preliminary dynamic dielectric behavior were interpreted in terms of the polarization phenomena known as the Maxwell-Wagner-Sillar effect.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 29 (1999), S. 74-80 
    ISSN: 1432-0789
    Keywords: Key words Methane production ; Flooded soil ; Incubation ; Soil organic matter ; Redox potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Soil CH4 production potentials were investigated by incubating air-dried soils under anaerobic conditions in the laboratory. Twenty-eight soils from different fields and locations were collected for this study. Soil CH4 production during a 100-day incubation differed greatly and were significantly correlated with soil organic content (r=0.61, P〈0.01). The statistical significance increased when soils were grouped according to soil reduction rates. A significant correlation was also found between CH4 production and total N content (r=0.64, P〈0.01) and between CH4 production and soil particle sizes of 0.25–0.05 mm (r=0.48, P〈0.05). A negative exponential correlation was found between CH4 production and aerobic soil pH (r=–0.74, P〈0.01). The 28 soils were stratified into four groups on the basis of variation in CH4 production rates which were associated with the soil reduction rate and soil organic content. The faster the Eh of soil fell, the more CH4 was formed. Adding rice straw to Hangzhou and Beijing soils increased CH4 production. The increase in CH4 production was more pronounced in the soil with the lowest organic matter content and slowest reduction rate than in the soil with highest organic matter and fastest reduction rate. Inorganic fertilizer had no significant influence on CH4 production potentials of either type of soil.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of environmental contamination and toxicology 59 (1997), S. 888-893 
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 29 (1999), S. 218-220 
    ISSN: 1432-0789
    Keywords: Key words Elevated atmospheric carbon dioxide ; Flooded soil ; Methane production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  CH4 production in a flooded soil as affected by elevated atmospheric CO2 was quantified in a laboratory incubation study. CH4 production in the flooded soil increased by 19.6%, 28.2%, and 33.4% after a 2-week incubation and by 38.2%, 62.4%, and 43.0% after a 3-week incubation under atmospheres of 498, 820, and 1050 μl l–1 CO2, respectively, over that in soil under the ambient CO2 concentration. CH4 production in slurry under 690, 920, and 1150 μl l–1 CO2 increased by 2.7%, 5.5%, and 5.0%, respectively, after a 3-day incubation, and by 6.7%, 12.8%, and 5.4%, respectively, after a 6-day incubation over that in slurry under the ambient CO2 concentration. The increase in CH4 production in the soil slurry under elevated CO2 concentrations in a N2 atmosphere was more pronounced than that under elevated CO2 concentrations in air. These data suggested that elevated atmospheric CO2 concentrations could promote methanogenic activity in flooded soil.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Meteorology and atmospheric physics 44 (1990), S. 43-61 
    ISSN: 1436-5065
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Summary Pentad mean anomaly maps were used to study the climatology of tropical intraseasonal convection anomaly (TICA) as a dynamic system. One hundred and twenty-two events were identified and classified into three categories: eastward (77), independent northward (27), and westward (18) propagation. The eastward propagation is more active in boreal winter than in summer, while the independent northward propagation, which is not associated with equatorial eastward propagation, occurs in boreal summer from May to October. The eastward moving TICA exhibits three major paths: 1) eastward along the equator from Africa to the mid-Pacific, 2) first eastward along the equator, then either turning north-east to the northwest Pacific or turning southeast to the southwest Pacific at the maritime continent, and 3) the main anomaly moves eastward along the equator with split center(s) moving northward over the Indian and/or western Pacific Oceans. The equatorial Indian Ocean and the western Pacific intertropical convergence zone are preferred geographic locations for their development, while the maritime continent and central Pacific are regions of dissipation. Independent northward propagation is confined to the Indian and western Pacific monsoon regions. Its existence suggests that the mechanism responsible for meridional propagation may differ from that for eastward propagation. The dynamic effect of the equator and the thermodynamic effect of the underlying warm ocean water are basic factors in trapping TICA in the deep tropics, while the annual march of maximum SST (thermal equator) and the monsoon circulation have profound influences on the annual variation and meridional movement of TICA.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Meteorology and atmospheric physics 56 (1995), S. 17-32 
    ISSN: 1436-5065
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Summary The transition from a cold to a warm state of the E1 Niño-Southern Oscillation (ENSO) cycle is studied using Comprehensive Ocean-Atmosphere Data Sets (COADS) for the period 1950–1992. The onset of El Niño (November to December of the year preceding the El Niño) is characterized by an occurrence of minimum sea-level pressure anomalies in the subtropics around the “node” line of the Southern Oscillation. This pressure fall favors the formation of the anomalous cyclonic circulations over the western Pacific and leads to the establishment of anomalous westerlies in the western equatorial Pacific during the boreal spring of the El Niño year. The westerly anomalies then intensify and propagate into the central Pacific by the end of the El Niño year. This is an essential feature of the development of a basin-wide warming. It is argued that the development of the equatorial westerly anomalies over the western Pacific may result from the thermodynamic coupling between the atmosphere and ocean. In boreal winter and spring the mean zonal winds change from westerly to casterly over the western equatorial Pacific. A moderate equatorial westerly anomaly initially imposed on such a mean state may create eastward SST gradients via changing rates of evaporational cooling and turbulent mixing. The equatorial SST gradients would, in turn, induce differential heating and zonal pressure gradients which reinforce the westerly anomalies. The feedback between the eastward SST gradients and westerly anomalies promotes the eastward propagation of the westerly anomalies.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Meteorology and atmospheric physics 47 (1991), S. 27-36 
    ISSN: 1436-5065
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Summary Wave-organized convective features in the southwest Indian Ocean are described using Hovmoller composites of satellite imagery, OLR anomalies and ECMWF precipitable water departures during the southern summer. Westward movement of large convective elements is noted in the 10–20°S latitude band in about half of the years between 1970 and 1984. A study of 47 convective systems from satellite imagery establishes the climatological features, including zonal propagation speeds for maritime systems in the range −2 to −4 m s−1, wavelengths of 25–35° longitude (3,000 km), lifespans of 10–20 days and convective areas of 7–10° longitude (800 km). Transient convective waves over the tropical SW Indian Ocean are slower and more diverse than their northern hemisphere counterparts. Interannual tendencies in the frequency and mode are studied. Wet summers over SE Africa correspond with an increased frequency of westward moving convective systems, whereas in dry summers convective systems tend to be quasi-stationary. INSAT data composites provide additional insight into the convective structure and show that tropical waves penetrated into southern Africa in February 1988. A more quantitative assessment of transient convective waves is provided by Hovmoller composites of OLR anomalies and precipitable water departures. Both display westward moving systems in 1976 and 1984 and highlight the wide variety and mixed mode character of convective waves. A case study is analyzed which illustrates the deepening of a moist, unstable layer coincident with the westward passage of a convective wave.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Letters in mathematical physics 39 (1997), S. 213-228 
    ISSN: 1573-0530
    Keywords: Seiberg--Witten monopoles ; Casson invariants ; topological Lagrangians.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract Dimensional reduction of the Seiberg--Witten equations leads to the equations of motion of a U(1) Chern--Simons theory coupled to a massless spinorial field. A topological quantum field theory is constructed for the moduli space of gauge equivalence classes of solutions of these equations. The Euler characteristic of the moduli space is obtained as the partition function which yields an analogue of Casson's invariant.A mathematically rigorous definition of the invariant isdeveloped for homology spheres using the theory of spectral flow ofself-adjoint Fredholm operators.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Climate dynamics 16 (2000), S. 677-691 
    ISSN: 1432-0894
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract  We describe a coupled tropical ocean-atmosphere model that represents a new class of models that fill the gap between anomaly coupled models and fully coupled general circulation models. Both the atmosphere and ocean are described by two and half layer primitive equation models, which emphasize the physical processes in the oceanic mixed layer and atmospheric boundary layer. Ocean and atmosphere are coupled through both momentum and heat flux exchanges without explicit flux correction. The coupled model, driven by solar radiation, reproduces a realistic annual cycle and El Nino-Southern Oscillation (ENSO). In the presence of annual mean shortwave radiation forcing, the model exhibits an intrinsic mode of ENSO. The oscillation period depends on the mean forcing that determines the coupled mean state. A perpetual April (October) mean forcing prolongs (shortens) the oscillation period through weakening (enhancing) the mean upwelling and mean vertical temperature gradients. The annual cycle of the solar forcing is shown to have fundamental impacts on the behavior of ENSO cycles through establishing a coupled annual cycle that interacts with the ENSO mode. Due to the annual cycle solar forcing, the single spectral peak of the intrinsic ENSO mode becomes a double peak with a quasi-biennial and a low-frequency (4–5 years) component; the evolution of ENSO becomes phase-locked to the annual cycle; and the amplitude and frequency of ENSO become variable on an interdecadal time scale due to interactions of the mean state and the two ENSO components. The western Pacific monsoon (the annual shortwave radiation forcing in the western Pacific) is primarily responsible for the generation of the two ENSO components. The annual march of the eastern Pacific ITCZ tends to lock ENSO phases to the annual cycle. The model's deficiencies, limitations, and future work are also discussed.
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