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: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: A sample of ombrotrophic peat from Moor House in northern England was extensively extracted with dilute nitric acid (pH 1) to free it of bound cations. Suspensions of the acid-washed peat (5–30 g l−1), prepared with different concentrations of background electrolyte (NaCl and KCl), were used to conduct batch acid–base titrations. A strong dependence of proton release on ionic strength (I) was observed, the apparent acid dissociation constant (pKapp) being found to decrease by approximately 1.0 for each tenfold increase in I. This behaviour could not be explained satisfactorily with Humic Ion-Binding Model VI, a discrete-site/electrostatic model of cation binding by humic substances, parameterized with data from laboratory studies on isolated samples. More success was obtained by abandoning the impermeable-sphere electrostatic submodel used in Model VI, and instead assuming the peat to consist of aggregates with fixed internal volume, and with counterion accumulation described by the Donnan model, as proposed by Marinsky and colleagues. The fixed-volume Donnan model (Model VI-FD) could also approximately explain other reported results from acid–base titrations of peat, including the effects on the titrations of complexing cations (Al, Ca, Cu). Copper titrations of the Moor House sample were performed using an ion-selective electrode, with peat suspensions in the acid pH range, at two ionic strengths, and in the presence of Al and Ca. The measured concentrations of Cu2+ were in the range 10−13−10−5 m. Model VI-FD provided reasonable fits of the experimental data, after optimization of the intrinsic binding constant for Cu, the optimized value being close to the default value derived previously from data referring to isolated humic substances. The optimized constants for Al and Ca, derived from their competition effects, were also close to their default values. Additional experiments were performed in which the centrifugation-depletion method was used to measure the binding of a cocktail of metals (Al, Ni, Cu, Zn, Cd, Eu, Pb) at a single pH. The model correctly predicted strong binding of Al, Cu, Eu and Pb, and weaker binding of Ni, Zn and Cd. For the strongly binding metals, the dissolved forms were calculated to be mainly due to complexes with dissolved humic matter, whereas the free ions (Ni2+, Zn2+, Cd2+) dominated for the weakly binding metals. Acid-washed soil appears to provide a valuable intermediate between isolated humic substances and untreated soil for the investigation of cation binding by natural organic matter in the natural environment.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 11 (1874), S. 88-88 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] I THINK I informed you about two years ago of the discovery of a bed of plants, with leaves, and a great variety of seeds, in this locality; also the wings of a Libellula, and the beak of a bird. As little interest was attracted, I have not hitherto informed you of the subsequent finding of a ...
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2019-04-02
    Description: Since its launch in October 1990, Ulysses has provided good quality magnetic field data, practically covering the whole time interval until now. We have studied the very long time scale evolution of the interplanetary magnetic field, in particlular, we have search for recurrent disturbances in the magnetic field. The magnetic field vectors have been mapped back to the Sun along Parker spirals, in order to determine the Heliographic longitude of the source regions in the corona. It was found that the position of many high field sources drifts systematically relative to the corona assumed to rotate with the equatorial rotation period of the Sun. The results are compared to similar observations on the eastward drift of magnetic sectors observed after about June 1992. Changes associated with both the declining phase of the solar cycle and the latitudinal excursion of Ulysses are also discussed.
    Keywords: SOLAR PHYSICS
    Type: Advances in Space Research (ISSN 0273-1177); 16; 9; p. (9)339
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2019-04-02
    Description: A detailed analysis of small period (15-900 sec) magnetohydrodynamic (MHD) turbulences of the interplanetary magnetic field (IMF) has been made using Pioneer-11 high time resolution data (0.75 sec) inside a Corotating Interaction Region (CIR) at a heliocentric distance of 2.5 AU in 1973. The methods used are the hodogram analysis, the minimum variance matrix analysis and the cohenrence analysis. The minimum variance analysis gives evidence of linear polarized wave modes. Coherence analysis has shown that the field fluctuations are dominated by the magnetosonic fast modes with periods 15 sec to 15 min. However, it is also shown that some small amplitude Alfven waves are present in the trailing edge of this region with characteristic periods (15-200 sec). The observed wave modes are locally generated and possibly attributed to the scattering of Alfven waves energy into random magnetosonic waves.
    Keywords: SOLAR PHYSICS
    Type: Advances in Space Research (ISSN 0273-1177); 16; 9; p. (9)171-(9)174
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2019-01-25
    Description: Magnetic field data from ISEE-3 in the distant magnetotail at crossings of the field reversal (or neutral sheet) region were analyzed to determine the instantaneous direction of the normal component Bz at the crossing. A crossing identified as being almost always tailward of the steady-state X-line was selected. Data for 1 hr are discussed to illustrate difficulties. One particular smooth crossing shows that complicated microstructure can occur in times less than 1 min. Averaging over long times may eliminate essential information. Inspection of the magnetic field data at the highest resolution, however, shows that the direction of the plasma sheet flows and the sense of Bz across the neutral sheet do not always agree with the reconnection models. Rather, they indicate that the low latitude boundary layer may play a significant role in the dynamics of the magnetotail.
    Keywords: SPACE SCIENCES (GENERAL)
    Type: CNES Proceedings of a Conference on the Comparative Study of Magnetospheric Systems; p 315-322
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Detailed measurements have been made of the magnetic field (0〈H〈6 T) and temperature (10 K〈T〈100 K) dependencies of the critical current density jc in Tl2CaBa2Cu2O8 films before and after irradiation with incremental fluences (0〈Φ〈3×1016 cm−2) of 2 MeV protons. The results are interpreted quantitatively in terms of radiation-induced changes in (1) the critical temperature, (2) the rate of thermal flux creep, and (3) local scale superconductivity. Radiation-induced enhancements in jc are described by an expression which allows the fluence that maximizes jc to be predicted as a function of H, T, pinning energy, and particle type.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report measurements of microwave surface resistance in Tl-based superconductor thin films made by laser ablation followed by a post-deposition thermal process. The films were measured by using cavity methods. The data at 9.5 and 148 GHz indicate that the residual resistance scales as f2. At 77 K, the 9.5 GHz surface resistance is ten times smaller than oxygen-free high-conductance copper at the same temperature and frequency. The 9.5 GHz measurement also indicates that the film-substrate interface does not cause more microwave loss than the film surface.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2018-06-11
    Description: Comet McNaught was the brightest comet observed from Earth in the last 40 years. For a period of five days in early 2007 February, four instruments on the Ulysses spacecraft directly measured cometary ions and key properties of the interaction of the comet's ion tail with the high-speed solar wind from the polar regions of the Sun. Because of the record-breaking duration of the encounter, the data are unusually comprehensive. O3(+) ions were detected for the first time in a comet tail, coexisting with singly charged molecular ions with masses in the range 28-35 amu. The presence of magnetic turbulence and of ions with energies up to approximately 200 keV indicate that at a distance of approximately 1.6 AU from the comet nucleus, the ion tail McNaught had not yet reached equilibrium with the surrounding solar wind.
    Keywords: Astronomy
    Type: The Astrophysical Journal; Volume 667; 1262-1266
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2018-06-08
    Description: A study is presented of 153 fast shock waves and their relation to other large-scale features in the solar wind: corotating interaction regions (CIRs), interplanetary counterparts of coronal mass ejections (ICMEs) and the magnetic sector structure, observed by Ulysses from October 1990 to the south solar pass in the summer of 1994.
    Keywords: Solar Physics
    Type: Journal of Geophysical Research
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2018-06-08
    Keywords: Geophysics
    Type: Fall 2001 American Geophysical Union; San Francisco, CA; United States
    Format: text
    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...