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  • 1
    Publication Date: 2015-05-16
    Description: In porous media, the nonwetting phase is trapped on water saturation due to capillary forces acting in a heterogeneous porous structure. Within the capillary fringe, the gas phase is trapped and released along with the fluctuation of the water table, creating a highly active zone for biological transformations and mass transport. We conducted column experiments to observe and quantify the magnitude and structure of the trapped gas phase at the pore scale using computed microtomography. Different grain size distributions of glass beads were used to study the effect of the pore structure on trapping at various capillary numbers. Viscous forces were found to have negligible impact on phase trapping compared with capillary and buoyancy forces. Residual gas saturations ranged from 0.5 to 10%, while residual saturation increased with decreasing grain size. The gas phase was trapped by snap-off in single pores but also in pore clusters, while this single-pore trapping was dominant for grains larger than 1 mm in diameter. Gas surface area was found to increase linearly with increasing gas volume and with decreasing grain size.
    Electronic ISSN: 1539-1663
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 2
    Publication Date: 2015-06-17
    Description: We investigated the inflammatory response, acute phase response and genotoxic effect of diesel exhaust particles (DEPs, NIST1650b) following a single intratracheal instillation. C57BL/6J BomTac mice received 18, 54 or 162 µg/mouse and were killed 1, 3 and 28 days post-exposure. Vehicle controls and the benchmark particle carbon black (CB, Printex 90; 162 µg/mouse) were tested alongside for comparison. The cellular composition and protein concentration were determined in bronchoalveolar lavage (BAL) fluid as markers for an inflammatory response. Pulmonary and systemic genotoxicity was analysed by the alkaline comet assay as DNA strand breaks in BAL cells, lung and liver tissue. The pulmonary acute phase response was analysed by Saa3 mRNA levels by real-time quantitative polymerase chain reaction. Instillation of DEP induced a strong neutrophil influx 1 and 3 days, but not 28 days post-exposure. Saa3 mRNA levels were increased at all time point for the highest dose and 28 days post-exposure for the middle dose. DEP increased levels of DNA strand breaks in lung tissue for all doses 1 day post-exposure and after 28 days for mid- and high-dose groups. Pulmonary exposure to DEP induced transient inflammation but long-lasting pulmonary acute phase response as well as genotoxicity in lung tissue 28 days post-exposure. The observed long-term pulmonary genotoxicity by DEP was less than the previously observed genotoxicity for CB using identical experimental set-up.
    Print ISSN: 0267-8357
    Electronic ISSN: 1464-3804
    Topics: Biology , Medicine
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  • 3
    Publication Date: 2015-06-18
    Description: Author(s): A. Kartavtsev, G. Raffelt, and H. Vogel Neutrinos propagating in media (matter and electromagnetic fields) undergo flavor and helicity oscillations, where helicity transitions are instigated both by electromagnetic fields and matter currents. In addition, it has been shown that correlations between neutrinos and antineutrinos of opposite ... [Phys. Rev. D 91, 125020] Published Tue Jun 16, 2015
    Keywords: Field Theory, Formal Particle Theory
    Print ISSN: 0556-2821
    Electronic ISSN: 1089-4918
    Topics: Physics
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  • 4
    Publication Date: 2019
    Description: Abstract Mineral dust is a key player in the Earth system that affects the weather and climate through absorbing and scattering the radiation. Such effects strongly depend on the optical properties of the particles that are in turn affected by the particle shape. For simplicity, dust particles are usually assumed to be spherical. But this assumption can lead to large errors in modeling and remote sensing applications. This study investigates the impact of dust particle shape on its direct radiative effect in a next‐generation atmospheric modeling system ICON‐ART (ICOsahedral Nonhydrostatic with Aerosols and Reactive Trace gases) to verify if accounting for non‐sphericity enhances the model‐observation agreement. Two sets of numerical experiments are conducted by changing the optical shape of the particles: one assuming spherical particles and the other one assuming a mixture of 35 randomly oriented tri‐axial ellipsoids. The simulations are compared to MISR, AERONET and CALIPSO observations (with focus on North Africa). The results show that consideration of particle non‐sphericity increases the dust AOD at 550 nm by up to 28% and leads to slight enhancement of the agreement between modeled and measured AOD. However, the model performance varies significantly when focusing on specific regions in North Africa. These differences stem from the uncertainties associated with particle size distribution and emission mechanisms in the model configuration. Regarding the attenuated backscatter, the simulated profile assuming non‐sphericity differs by a factor of 2 to 5 from the experiment assuming spherical dust, and is in a better agreement with the CALIPSO observations.
    Print ISSN: 2169-897X
    Electronic ISSN: 2169-8996
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 5
    Publication Date: 2017-07-14
    Description: Interest in energy storage technologies is still increasing in times of the excess of electricity that is generated by wind farms or solar plants. Solar electricity can be transformed to solar-hydrogen via water electrolysis. A crucial part of the energy storage technologies plays the efficient conversion of H 2 and CO 2 from renewable resources. Here, the process conditions for continuously catalytic hydrogenation of CO 2 to CH 3 OH under supercritical conditions over lab-synthesized Cu/ZnO/Al 2 O 3  catalysts were investigated. The impact of temperature (230 – 330 °C), residence time (0.5 - 2.2 s) at moderate pressure (150 bar) but even above the supercritical parameters of CO 2 showed a selective CO 2 hydrogenation. Higher H 2 concentrations, respectively higher H 2 :CO 2 -ratios (H 2 :CO 2  = 6), lead to an increased selectivity of CH 3 OH. A possible in situ phase separation of reaction products within the reactor due to the higher densities of the reaction mixture by the highered pressure could affect the kinectics and simplfy the down-stream processing. The combination of thermodynamic studies (phase separation phenomena) as well as the catalytic performance tests for the CO2 hydrogenation under supercritical conditions are discussed. Based on these data a process concept is presented.
    Print ISSN: 0930-7516
    Electronic ISSN: 1521-4125
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Published by Wiley
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  • 6
    Publication Date: 2020-02-24
    Description: The bulk magnetic mineral record from Lake Ohrid, spanning the past 637 kyr, reflects large-scale shifts in hydrological conditions, and, superimposed, a strong signal of environmental conditions on glacial–interglacial and millennial timescales. A shift in the formation of early diagenetic ferrimagnetic iron sulfides to siderites is observed around 320 ka. This change is probably associated with variable availability of sulfide in the pore water. We propose that sulfate concentrations were significantly higher before 320 ka, due to either a higher sulfate flux or lower dilution of lake sulfate due to a smaller water volume. Diagenetic iron minerals appear more abundant during glacials, which are generally characterized by higher Fe = Ca ratios in the sediments. While in the lower part of the core the ferrimagnetic sulfide signal overprints the primary detrital magnetic signal, the upper part of the core is dominated by variable proportions of high- to low-coercivity iron oxides. Glacial sediments are characterized by high concentration of high-coercivity magnetic minerals (hematite, goethite), which relate to enhanced erosion of soils that had formed during preceding interglacials. Superimposed on the glacial–interglacial behavior are millennial-scale oscillations in the magnetic mineral composition that parallel variations in summer insolation. Like the processes on glacial–interglacial timescales, low summer insolation and a retreat in vegetation resulted in enhanced erosion of soil material. Our study highlights that rock-magnetic studies, in concert with geochemical and sedimentological investigations, provide a multi-level contribution to environmental reconstructions, since the magnetic properties can mirror both environmental conditions on land and intra-lake processes.
    Description: Published
    Description: 2093–2109
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Description: JCR Journal
    Description: open
    Keywords: Environmental magnetism Pleistocene Lake Ohrid ; 04. Solid Earth::04.05. Geomagnetism::04.05.09. Environmental magnetism
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 6 (1950), S. 187-188 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary (1) Calcium deposits in the bile ducts of cattle, caused by infestation withFasciola hepatica, consist of hydroxyl apatite in granules of about 10−5 to 10−6 cm3 in size. (2) Egg-shaped calcareous bodies fromTænia saginata consist of the two kinds of crystals hydroxyl apatite and brucite.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 5 (1954), S. 41-43 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Progress in the Manufacture of Acidresistant StonewareOne of the distinguishing features of stoneware is its resistance to chemical action and its outstanding mechanical properties. These qualities permitted the development of stoneware to keep pace with that of the chemical industry.The article describes further progress in the field of acid-resistant stoneware. Particular emphasis is laid on the development of special mixtures having great powers of resistance to temperature changes, at the same time retaining their excellent heat-conducting properties. Improvements in the mechanical working of stoneware are also discussed.The mechanical working of stoneware by grinding, polishing and threading has been brought to the point where the accuracy and finish of the work is equivalent to that obtaining in metal working practice. A new field of application of stoneware was thereby opened. The production of air and dust locks for use in installation working with ultrafine abrasive dust particles is an example. Stoneware rollers having precision ground surfaces are used in various industries. Ground, polished and threaded stoneware components enable many improvements and simplifications to be made in the design of machinery and equipment for the chemical industry.
    Notes: Kennzeichnend für den Werkstoff Steinzeug sind seine Beständigkeit gegenüber chemischer Korrosion und seine ausgezeichneten mechanischen Eigenschaften. Beides waren die Voraussetzungen, um mit der Entwicklung der chemischen Großindustrie Schritt halten zu können.In der Abhandlung werden weitere Fortschritte auf dem Gebiet des säurefesten Steinzeug besprochen. Diese werden besonders deutlich durch Entwicklung von temperaturwechselbeständigen und wärmeleitfähigen Spezialmassen und durch Verbesserung der Nachbearbeitungsmethoden.Die mechanische Bearbeitung von Steinzeug durch Schleifen, Polieren und Gewindeschneiden wurde so weit entwickelt, daß eine Vergütung und Maßgenauigkeit möglich ist, wie in der Metallindustrie. Dadurch wurden dem Steinzeug neue Anwendungsmöglichkeiten erschlossen. Beispielsweise werden Staubschleusen zur Förderung von feinsten aggressiven Staubteilchen hergestellt. Steinzeugwalzen mit präzisem Schliff der Oberfläche finden in verschiedenen Industriezweigen Verwendung. Geschliffene, polierte und mit Gewinde versehene Steinzeugteile brachten Vereinfachungen und Verbesserungen im Steinzeugmaschinen- und Apparatebau.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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