ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
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
    Spacer-modified stationary phases for anion chromatography: Alkyl- and carbonylalkylspacers – A comparison (2000)
    Springer
    Fresenius' journal of analytical chemistry 366 (2000), S. 341-345 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A comparison of two separation columns for high-capacity anion chromatography is presented. The distinctive feature of both packing materials is the structure of the alkyl-chain (spacer-group) between the polymer-backbone and the functional group. All other parameters, e.g. exchange capacity, functionality and length of the spacer-arm, are identical. The retention behavior of the so-called standard-anions is investigated on both columns under identical chromatographic conditions using an experimental design technique in the course of which the composition of the elution system applied is varied. The statistical treatment of the retention data offers the possibility to explain the different chromatographic behavior of both stationary phases, at least qualitatively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050069
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Modifying the fatigue properties of polyamide treated by the thermal method under pressure (1977)
    Springer
    Mechanics of composite materials 13 (1977), S. 848-851 
    Details
    ISSN: 1573-8922
    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
    URL: http://dx.doi.org/10.1007/BF00866991
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Effect of the characteristics of sinusoidal and rectangular cycles on the endurance limit of pipes of a laminated epoxy fiber glass plastic (1986)
    Springer
    Mechanics of composite materials 21 (1986), S. 432-439 
    Details
    ISSN: 1573-8922
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Conclusions 1. Examination of the fatigue of fiber glass plastic pipes in loading with the sinusoidal cycle can be replaced with an error of up to 10% by tests with the right-angled cycle in equipment of simple design. 2. The endurance limit in the right-angled cycle is lower than in the sinusoidal cycle. Therefore, in testing the pipes it is necessary to avoid sharp changes in internal pressure if the winding angle is αi〉 15°. 3. The tangential stress corresponding (with an error of up to 15%) to the endurance limit in the right-angled load cycle can be determined on the basis of acoustic emission in static internal pressure loading.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00610891
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Determination of nitrite and bromate in disinfected water samples at the low μg/L level by means of a high-capacity anion exchanger (1997)
    Springer
    Fresenius' journal of analytical chemistry 358 (1997), S. 551-553 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Bromate and nitrite are formed during the disinfection of water. The German threshold value for nitrite in drinking water is 100 μg/L, for bromate a limit below 50 μg/L has to be established. A self-made high-capacity resin with 2-(dimethylamino)-ethanol functionality in combination with a UV-transparent elution system based on perchloric acid allows the separation and sensitive photometric detection of nitrite and bromate, even if high chloride concentrations are present. The high capacity of the strongly basic resin allows sample volumes of up to 400 μL without disturbance of the separation. Detection limits for bromate and nitrite are 15 and 10 μg/L, respectively. The direct analysis of water samples with high salt contents, such as disinfected pool water, is possible by insertion of an on-line chloride removal step.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050467
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    The mechanisms of water diffusion in polymerized silicate melts (1997)
    Springer
    Contributions to mineralogy and petrology 126 (1997), S. 377-385 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Diffusion of water was experimentally investigated for melts of albitic (Ab) and quartz-orthoclasic (Qz29Or71, in wt %) compositions with water contents in the range of 0 to 8.5 wt % at temperatures of 1100 to 1200 °C and at pressures of 1.0 and 5.0 kbar. Apparent chemical diffusion coefficients of water (D water) were determined from concentration-distance profiles measured by FTIR microspectroscopy. Under the same P-T condition and water content the diffusivity of water in albitic, quartz-orthoclasic and haplogranitic (Qz28Ab38 Or34, Nowak and Behrens, this issue) melts is identical within experimental error. Comparison to data published in literature indicates that anhydrous composition only has little influence on the mobility of water in polymerized melts but that the degree of polymerization has a large effect. For instance, Dwater is almost identical for haplogranitic and rhyolitic melts with 0.5–3.5 wt % water at 850 °C but it is two orders of magnitude higher in basaltic than in haplogranitic melts with 0.2–0.5 wt % water at 1300 °C. Based on the new water diffusivity data, recently published in situ near-infrared spectroscopic data (Nowak 1995; Nowak and Behrens 1995), and viscosity data (Schulze et al. 1996) for hydrous haplogranitic melts current models for water diffusion in silicate melts are critically reviewed. The NIR spectroscopy has indicated isolated OH groups, pairs of OH groups and H2O molecules as hydrous species in polymerized silicate melts. A significant contribution of isolated OH groups to the transport of water is excluded for water contents above 10 ppm by comparison of viscosity and water diffusion data and by inspection of concentration profiles from trace water diffusion. Spectroscopic measurements have indicated that the interconversion of H2O molecules and OH pairs is relatively fast in silicate glasses and melts even at low temperature and it is inferred that this reaction is an active step for migration of water. However, direct jumps of H2O molecules from one cavity within the silicate network to another one can not be excluded. Thus, we favour a model in which water migrates by the interconversion reaction and, possibly, small sequences of direct jumps of H2O molecules. In this model, immobilization of water results from dissociation of the OH pairs. Assuming that the frequency of the interconversion reaction is faster than that of diffusive jumps, OH pairs and water molecules can be treated as a single diffusing species having an effective diffusion coefficient . The shape of curves of Dwater versus water content implies that increases with water content. The change from linear to exponential dependence of Dwater between 2 and 3 wt % water is attributed to the influence of the dissociation reaction at low water content and to the modification of the melt structure by incorporation of OH groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004100050257
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    An experimental investigation on diffusion of water in haplogranitic melts (1997)
    Springer
    Contributions to mineralogy and petrology 126 (1997), S. 365-376 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract   The diffusivity of water has been investigated for a haplogranitic melt of anhydrous composition Qz28Ab38Or34 (in wt %) at temperatures of 800–1200°C and at pressures of 0.5–5.0 kbar using the diffusion couple technique. Water contents of the starting glass pairs varied between 0 and 9 wt %. Concentration-distance profiles for the different water species (molecular water and hydroxyl groups) were determined by near-infrared microspectroscopy. Because the water speciation of the melt is not quenchable (Nowak 1995; Nowak and Behrens 1995; Shen and Keppler 1995), the diffusivities of the individual species can not be evaluated directly from these profiles. Therefore, apparent chemical diffusion coefficients of water (D water) were determined from the total water profiles using a modified Boltzmann-Matano analysis. The diffusivity of water increases linearly with water content 〈3 wt % but exponentially at higher water contents. The activation energy decreases from 64 ± 10 kJ/mole for 0.5 wt % water to 46 ± 5 kJ/mole for 4 wt % water but remains constant at higher water contents. A small but systematic decrease of D water with pressure indicates an average activation volume of about 9 cm3/mole. The diffusivity (in cm2/s) can be calculated for given water content (in wt %), T (in K) and P (in kbar) by in the ranges 1073 K ≤ T ≤ 1473 K; 0.5 kbar ≤ P≤ 5␣kbar; 0.5 wt % ≤ C water ≤ 6 wt %. The absence of alkali concentration gradients in the glasses after the experiments shows that interdiffusion of alkali and H+ or H3O+ gives no contribution to the transport of water in aluminosilicate melts. The H/D interdiffusion coefficients obtained at 800°C and 5 kbar using glass pieces with almost the same molar content of either water or deuterium oxide are almost identical to the chemical diffusivities of water. This indicates that protons are transported by the neutral component H2O under these conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004100050256
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Reversible hydration in synthetic mixite, BiCu6(OH)6(AsO4)3·nH2O (n≤3): hydration kinetics and crystal chemistry (1997)
    Springer
    Physics and chemistry of minerals 24 (1997), S. 411-422 
    Details
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract  The presence of zeolitic water, with a reversible hydration behaviour, was determined by structural and kinetic studies on synthetic mixite BiCu6(OH)6(AsO4)3·nH2O (n≤3). X-ray diffraction and infrared-spectroscopic investigations were performed on single crystals. Isothermal thermogravimetric experiments were carried out to determine the reaction kinetics of the de- and rehydration processes. The single-crystal structure refinement of a fully hydrated crystal yielded five partially occupied Ow positions (Ow=oxygen atom of a H2O molecule) within the tube-like channels of the hexagonal [BiCu6(OH)6(AsO4)3] framework. For the partially dehydrated form, with n≈1, at least two of these sites were found to be occupied significantly. In addition, the structural investigations allowed two different intra-framework hydrogen bonds to be distinguished that are independent of the extra-framework water distribution and are responsible for the stability of the self-supporting framework. The kinetic analysis of the rate data in the 298–343K temperature range shows that the dehydration behaviour obeys a diffusion-controlled reaction mechanism with an empirical activation energy of E a dehyd=54±4 kJ mol–1. A two-stage process controls rehydration of which the individual steps were attributed to an initial surface-controlled (E a hyd-I=6±1 kJ mol–1) and subsequent diffusion-controlled reaction mechanism (E a hyd-II=12±1 kJ mol–1). The estimated hydration enthalpy of 42±5 kJ mol–1 supports the distribution model of molecular water within the channels based on a purely hydrogen-bonded network.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002690050055
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Organochlorine Pesticide Contamination in Neotropical Migrant Passerines (1996)
    Springer
    Archives of environmental contamination and toxicology 31 (1996), S. 386-390 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract. Organochlorine pesticide levels were determined in Neotropical migrant passerines which have populations reported to be declining. Pesticide residues ranging from 0.385 to 27.4 ng/g were found in 19 of 21 birds, including both Hatch Year (HY) and After Hatch Year (AHY) age classes of nine different species. Eighteen of the 19 birds contained p,p′-DDE, while dieldrin was found in 16 birds and heptachlor epoxide was present in 10 birds. There were no significant differences in pesticide levels between HY and AHY birds, suggesting that HY birds are exposed to pesticides in their diet on the breeding ground or that pesticides are acquired from contaminated mothers, or both. Pesticide levels were not related to gender. Although the effects of these low residue levels on passerine fecundity are unknown, their presence has potential conservation implications for passerines and for the raptorial birds that feed upon them.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002449900122
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    High-pressure crystal chemistry of chromous orthosilicate, Cr2SiO4. A single-crystal X-ray diffraction and electronic absorption spectroscopy study (1999)
    Springer
    Physics and chemistry of minerals 26 (1999), S. 446-459 
    Details
    ISSN: 1432-2021
    Keywords: Key words Chromous silicate ; High-pressure ; Crystal chemistry ; Chromium dimer ; Metal-metal bonding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract The high-pressure behaviour of chromous orthosilicate, Cr2SiO4, has been studied by means of single-crystal X-ray diffraction and electronic absorption spectroscopy. X-ray diffraction data show that the structure remains orthorhombic to the highest pressure reached of 9.22 GPa. The compressibility of the unit-cell is strongly anisotropic with the c axis approximately six times more compressible than the a and b axes. A third-order Birch-Murnaghan equation of state fitted to the volume-pressure data yields V 0 = 610.10(3) Å3, K = 94.7(4) GPa, K′ = 8.32(14). Cr2SiO4 is therefore more compressible than the isostructural Cd analogue, even though its molar volume is smaller. This unusual behaviour can be attributed to the fact that the Cr atom is too small for the six-coordinated site that it occupies, and the site is therefore strongly distorted. Structure refinements indicate that under high pressures the Cr atom remains strongly displaced from the central position of the octahedron. Polarized and unpolarized electronic absorption spectra include a strong absorption band occuring at 18.300 cm−1 for E//c (which is parallel to the shortest Cr-Cr vector in the structure) which has an unusually large half width (5000 cm−1), indicative of electronic interaction between metal centres. Deconvolution of unpolarized high-pressure spectra show that the relative integrated intensity of this component increases linearly from 40% at 1 bar to 60% at 11.2 GPa. Both the structural changes and the absorption spectra at high pressures suggest that pairs of adjacent Cr atoms in chromous orthosilicate form chromium dimers with a weak metal-metal bond, which is consistent with the diamagnetic response found at ambient pressure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002690050207
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Direct photon production beyond leading log approximation—q+q→γ+q+q contribution (1983)
    Springer
    The European physical journal 17 (1983), S. 249-257 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Theq+q→γ+q+q contribution (for incoming quarks of equal and different flavours) to the next-to-leading correction for the direct photon production inpp collisions is calculated, analyzed in terms of double moments and compared with the data. The dimensional regularization method is used and the final state Bremsstrahlung infinities are regularized by an angular cut-off. The correction is found to be 30–40% of the Born contribution providing a better description of the data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01578151
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...