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  • 1
    Electronic Resource
    Electronic Resource
    Determination of the pore widths of highly porous materials with NMR microscopy (1997)
    Springer
    Fresenius' journal of analytical chemistry 357 (1997), S. 508-513 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The quantitative characterization of macro-porous materials with regard to pore width and pore width distribution was accomplished for the first time by using 1H-NMR microscopy in combination with suitable methods of digital image analysis. Here we present the newly developed algorithm and discuss the first experimental results. Large-pored glass filter systems filled with silicon oil as intrusion fluid were used as references. Silicates of unknown pore width were analyzed both with the new method and with Hg intrusion. NMR image data were recorded using a 3D spin echo sequence, which gave 128 slice images with a spatial resolution of 14.5 μm × 14.5 μm within each slice, with a slice-thickness of 37 μm or 48 μm. A quantitative evaluation of the 3D NMR data, with regard to pore width and pore width distribution, was done using the appropriate image processing function of the HORUS program. Individual slice evaluation was performed first, followed by an analysis of the binding elements between the slices. Pore widths of the glass filters determined using this analytical algorithm were in accordance with the manufacturer’s values, and silicate pore widths were in good agreement with the values determined by Hg intrusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050203
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  • 2
    Electronic Resource
    Electronic Resource
    Three-segment electrodiffusion probe for velocity measurements (1991)
    Springer
    Experiments in fluids 11 (1991), S. 186-190 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A cylindrical electrodiffusion probe for the measurement of liquid velocity vectors in the plane perpendicular to its axis was developed as an analogue to the triple-split film thermoanemometer. The geometry of the probe enables high directional resolution in the whole range of 360°. The total mass transfer of the probe was well correlated by the relation Sh = 0.76 Sc 0.33 Re 0.47.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00190298
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  • 3
    Electronic Resource
    Electronic Resource
    Sensitivity of three-segment electrodiffusion probes to eddy shedding (1994)
    Springer
    Experiments in fluids 16 (1994), S. 368-374 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The influence of eddy shedding on the instantaneous readings of a three-segment cylindrical electrodiffusion velocity probe was investigated in an immersed jet with a very low turbulence intensity, σ = 1.2%. The velocity fluctuations measured by the three-segment probe were smaller than 2.6%, and the maximum error in the flow angle estimation was 2∘. Vortices with the Strouhal frequency were detected by a simple electrodiffusion probe placed downstream of the three-segment probe, but no peaks with this frequency were found on the frequency spectra of the three-segment probe. From the probe response to a stepwise change of the polarization voltage the characteristic times of the transient process were estimated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00202060
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  • 4
    Electronic Resource
    Electronic Resource
    Electrodiffusional direction-specific probe for measuring local velocity of aerated aqueous systems (1991)
    Springer
    Journal of applied electrochemistry 21 (1991), S. 1073-1076 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A three-segment direction specific probe based on the electrodiffusion measuring technique was used to measure local liquid velocities in gas-liquid flow. Dissolved oxygen was employed as depolarizer instead of the usually applied redox system ferro-ferricyanide in water. The concentration of the auxiliary electrolyte K2SO4 was so low that coalescence behaviour of the gas-liquid system was not influenced. It was possible to measure liquid velocities up to ca 100cm s−1. The probe showed satisfying sensitivity to flow direction. Furthermore, unequivocal discrimination between signals from the liquid and gas phases was achieved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01041449
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  • 5
    Electronic Resource
    Electronic Resource
    Determination of local hydrodynamic parameters in bubble columns by the electrodiffusion method with oxygen as depolarizer (1994)
    Springer
    Journal of applied electrochemistry 24 (1994), S. 666-669 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract An electrodiffusional three-segment probe was developed with which local axial and radial liquid velocities can be determined. Application of this probe in gas-liquid flow yields information on local gas hold-up. In coalescing media the commonly used redox-system Fe(CN) 6 3− /Fe(CN) 6 4 should be replaced by dissolved oxygen as depolarizer. Measurements of local axial and radial liquid velocity and turbulence intensity in different bubble columns (D = 150 and 600 mm) showed good agreement with data obtained by hotfilm anemometry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00252093
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  • 6
    Electronic Resource
    Electronic Resource
    Fluoridolyse von N-Phosphorylphosphazenen (1995)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 621 (1995), S. 865-870 
    Details
    ISSN: 0044-2313
    Keywords: Fluoridolysis ; N-Phosphoryl Phosphazenes ; Fluorophosphates ; Diazadiphosphetine ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fluoridolysis of N-Phosphoryl PhosphazenesIn the reaction of the N-phosphoryl phosphazenes X3P=N—P(Y)X2 (X = Cl, PhO, Et2N, CF3CH2O, PrS, Ph; Y = O, S) (1-18) with Et3N · nHF (n ≍ 3 or 0.6) fluoro derivatives of N-phosphoryl phosphazenes (see table 2) as well as N-phosphorylated imiddotetrafluorophosphates, [F4P=N—P(Y)Cl2]- (Y = O, S), and imidopentafluorophosphates, [F5P—N—P(Y)X2]2- or [F5P—NH—P(O)X2]- (see table 3), are formed. t-BuNHPCl2=N—POCl2 reacts in acetonitrile with Et3N or i-Pr2EtN to form a product, representing probably the diazadiphosphetine (5 b).
    Notes: Bei der Umsetzung der N-Phosphorylphosphazene X3P=N—P(Y)X2 (X = Cl, PhO, Et2N, CF3CH2O, PrS, Ph; Y = O, S) (1-18) mit Et3N · nHF (n ≍ 3 oder 0,6) werden durch den Austausch von Chlor sowie PhO-, Et2N- und CF3CH2O-Gruppen gegen Fluor Fluorderivate von N-Phosphorylphosphazenen (siehe Tab. 2) sowie N-phosphorylierte Imiddotetra- und -pentafluorophosphate, [F4P=N—P(Y)Cl2]- (Y = O, S) und [F5P—N—P(Y)X2]2- bzw. [F5P—NH—P(O)X2]- (siehe Tab. 3) gebildet. t-BuNHPCl2=N—POCl2 reagiert in Acetonitril mit Et3N oder i-Pr2EtN zu einem Produkt, bei dem es sich höchstwahrscheinlich um das Diazadiphosphetin (5 b) handelt.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19956210527
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  • 7
    Electronic Resource
    Electronic Resource
    Fluoridolyse von Diphosphorylverbindungen (1995)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 621 (1995), S. 894-900 
    Details
    ISSN: 0044-2313
    Keywords: Fluoridolysis ; Imidodiphosphoryl Compounds ; Methanediphosphonic Acid Derivatives ; Azadiphosphetidine ; Pentafluorophosphates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fluoridolysis of Diphosphoryl CompoundsThe behaviour of diphosphoryl compounds [X2(O)P]2Y in fluoridolysis reactions is decisively determined by the nature of the bridging group Y. In the cases of Y = NH and CH2 and X = Cl [F2P(O)]2N- and [F2P(O)]2CH2 are obtained quantitatively. For Y = NPh, O, and CH2 the formation of phosphorylated pentafluorophosphates [F5P—Y—POX2]- is observed. Amido and ester derivatives containing fluorine (see table 2) are obtained from the corresponding chloro compounds by Cl/F exchange. Fluoridolysis of the azadiphosphetidine 19 results in the formation of acyclic 19 a.
    Notes: Das Fluoridolyseverhalten von Diphosphorylverbindungen [X2(O)P]2Y wird maßgeblich durch die Brückengruppe Y bestimmt. Im Falle von Y = NH und CH2 sowie X = Cl werden quantitativ [F2P(O)]2N- und [F2P(O)]2CH2 erhalten. Für Y = NPh, O und CH2 wird die Bildung von phosphorylierten Pentafluorophosphaten [F5P—Y—POX2]- beobachtet. Aus chlorhaltigen Amido- und Esterderivaten werden durch Chlor-Fluor-Austausch die entsprechenden Fluorderivate erhalten (siehe Tab. 2). Die Fluoridolyse des Azadiphosphetidins 19 ergibt die acyclische Verbindung 19 a.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19956210531
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  • 8
    Electronic Resource
    Electronic Resource
    Über den Einfluß von Temperatur und Fremdionen auf Eigenschaften und Bau der Natriumwasserglaslösungen (1992)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 614 (1992), S. 95-101 
    Details
    ISSN: 0044-2313
    Keywords: silicate solution ; water glass ; NMR spectroscopy ; dre adsorption ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Influence of Temperature and Impurities Addition on the Properties and the Constitution of Sodium Water Glass SolutionsSodium water glass (NaWG-)solutions of constant composition (SiO2/Na2O = 3,3; CSiO2 = 6,2 M) and different concentration of impurities (Fe, Al, Ti, Cu, chloride, sulfate) were investigated in dependence on temperature by means of the dye absorption method, 1H- and 23Na-NMR spectroscopy. It is shown, that the differences in the dye absorption spectra of normalized technical NaWG-solutions, mainly depend on the Fe-concentration in the solutions and their thermal history. From the results follow a crosslinking of polymeric silicate species by Fe—O—Si bonds and/or hydrogen bridges and a fully or partially degradation of these bonds at higher temperatures (150°C).
    Notes: Natriumwasserglas-(NaWG-)lösungen konstanter Zusammensetzung (SiO2/Na2O = 3,3; CSio2 = 6,2 M) und mit unterschiedlichen Fremdatomgehalten (Fe, Al, Ti, Cu, Chlorid, Sulfat) wurden in Abhängigkeit ihrer thermischen Vorbehandlung mit Hilfe der Farbstoffadsorptionsmethode sowie der 1H- und 23Na-NMR-Spektroskopie untersucht. Es zeigt sich, daß die Unterschiede in den Farbstoffspektren normierter technischer NaWG-Lösungen im wesentlichen von dem Fe-Gehalt der Lösungen und ihrer „thermischen Vergangenheit“ abhängen. Die Ergebnisse der Farbstoffmethode und NMR deuten darauf hin, daß in Fe-haltigen NaWG-Lösungen bei 80°C Vernetzungen der polymeren Silicatteilchen über Fe—O—Si-Bindungen und/oder Wasserstoffbrückenbindungen erfolgen, die bei höheren Temperaturen (150°C) wieder ganz oder teilweise gelöst werden.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19926140817
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  • 9
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    Microbes are trophic analogs of animals [Ecology] (2015)
    National Academy of Sciences
    Details
    Publication Date: 2015-12-09
    Description: In most ecosystems, microbes are the dominant consumers, commandeering much of the heterotrophic biomass circulating through food webs. Characterizing functional diversity within the microbiome, therefore, is critical to understanding ecosystem functioning, particularly in an era of global biodiversity loss. Using isotopic fingerprinting, we investigated the trophic positions of a broad...
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
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  • 10
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    Predation shapes the movement of a well-defended species, the North American porcupine, even when nutritionally stressed (2016)
    Oxford University Press
    Details
    Publication Date: 2016-03-19
    Description: Animals reduce their exposure to predation often at the cost of nutritional inputs. A variety of predator avoidance strategies exist, but species generally exist along a spectrum with some primarily utilizing behavioral responses to avoid predation and others relying more on morphological defenses to deter predation. North American porcupines ( Erethizon dorsatum ) possess a well-developed predator deterrent strategy (i.e., quills). During the winter, porcupines enter a nutritional bottleneck where they principally rely on endogenous stores to survive winter. We hypothesized that porcupine behavior in winter would, then, be primarily driven by nutritional demands rather than predation risk. To test this trade-off between perceived risk of predation and nutritional stress, we analyzed the length and sinuosity of movement patterns, relative to nutritional condition (urinary urea: creatinine), snow conditions (depth, density), and a risk landscape (predation risk and refuges). As predicted, the sinuosity of movement paths was unrelated to any of our variables, but we detected a strong correlation between lengths of movements with risk landscape. Specifically, the length of porcupine movement declined as the average risk of predation increased, and the presence of refuge trees in their movement path was positively related to path length. Thus, even for animals possessing extreme morphological defenses effective at deterring predation, and during a period of nutritional stress, movement and behavior are nevertheless driven by perceived predation risk.
    Print ISSN: 1045-2249
    Electronic ISSN: 1465-7279
    Topics: Biology
    Published by Oxford University Press
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