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  • 1995-1999  (4)
  • NaHSO4  (2)
  • BaTiO3  (1)
  • decahydroquinolines
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Materials research innovations 1 (1997), S. 44-52 
    ISSN: 1433-075X
    Keywords: Key words Microwave ; Synthesis ; Processing ; WC ; BaTiO3 ; Hydrothermal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  The innovations in microwave processing of ceramics have been dominated to date by serendipitous discovery, because the interaction between such radiation as delivered via available tools and the materials of widely varying properties, sizes, and shapes is so complex that it has defied quantitative analysis. For over 10 years a wide variety of inorganic ceramic and semiconducting materials have been synthesized, sintered, and reacted in our own labs, including microwave hydrothermal synthesis of metals, ferrites, and electroceramic phases. These local results are summarized and used as the reference point for reporting on two different new advances: sintering of WC-Co composite tool bits and other similar objects in under 15 min, while retaining extremely fine microstructures, without any grain growth inhibitors; using reduced TiO2 or Ta2O5 for the synthesis of phases such as BaTiO3, Ba3MgTa2O9, and Pb(Zr.Ti)O3 in a few minutes in a 2.45 GHz field at the astonishing temperatures of 300–700 ºC.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1572-8927
    Keywords: Activity coefficient ; electromotive force ; Pitzer ; HCl ; Na2SO4 ; NaHSO4
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The electromotive force of HCl–Na2SO4 solutions has been determined from 5 to 50°C and ionic strengths from 0.5 to 6m with a Harned type cell $${\text{Pt; H}}_{\text{2}} ({\text{g, 1 atm}})|{\text{HCl(}}m_1 {\text{) + Na}}_{\text{2}} {\text{SO}}_{\text{4}} {\text{(}}m_2 {\text{)}}|{\text{AgCl, Ag}}$$ The results have been used to determine the activity coefficient of HCl in the mixtures. The activity coefficients have been analyzed with the Pitzer equations to account for the ionic interactions. The measurements were used to determine interaction coefficients (β0, β1) for NaHSO4 solutions from 5 to 50°C. The model represents the mean activity coefficients of HCl in the mixtures to ±0.005 over the entire temperature and concentration range of the measurements. The results have been combined with literature data to provide parameters that are valid from 0 to 250°C for NaHSO4 solutions.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-1561
    Keywords: Alkaloids ; mass spectrometry ; infrared spectroscopy ; amphibians ; ants ; decahydroquinolines ; quinolizidines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Three alkaloids—two minor decahydroquinolines (DHQs) and a major quinolizidine—were detected in an extract of a Brazilian myrmicine ant (Solenopsis (Diplorhoptrum) sp. picea group). One DHQ (3) was identical to a known frog-skin alkaloid, cis-195A (cis-5-methyl-2-propyldecahydroquinoline), while the second DHQ, an isomer of 3, designated 195J, was assigned a tentative cis-2-methyl-5-propyldecahydroquinoline structure (2) based on mass and infrared spectra. The third alkaloid proved identical to the frog-skin alkaloid 195C, for which a structure had not been previously proposed. Mass and infrared spectral analysis, including chemical ionization tandem mass spectrometry, indicated a 4-methyl-6-propylquinolizidine structure (1) for 195C. The four possible diastereomers were synthesized and the (6Z,10E)-4-methyl-6-propylquinolizidine diastereomer (1b) was identical to the natural alkaloid. Skin extracts of a population of a Madagascan mantelline frog contained, among other alkaloids, minor amounts of the same alkaloid triad 1–3 with 1 again predominating. The common occurrence of alkaloids 1–3 in both ant and frog supports the hypothesis that ants are a likely dietary source for sequestered frog-skin alkaloids and brings to six, the alkaloid classes common to ant and frog.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1572-8927
    Keywords: Activity coefficient ; electromitive force ; Pitzer, HCl ; Na2SO4 ; NaHSO4
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The electromotive force of HCl−Na2SO4 solutions has been determined from 5 to 50°C and ionic strengths from 0.5 to 6m with a Harned type cell $$Pt; H_2 (g, 1 atm)|HCl(m_1 ) + Na_2 SO_4 (m_2 )|AgCl, Ag$$ The results have been used to determine the activity coefficient of HCl in the mixtures. The activity coefficiencts have been analyzed with the Pitzer equations to account for the ionic interactions. The measurements were used to determine interaction coefficients (β0, β1) for NaHSO4 solutions from 5 to 50°C. The model represents the mean activity coefficients HCl in the mixtures to ±0.005 over the entire temperature and concentration range of the measurements. The results have been combined with literature data to provide parameters that are valid from 0 to 250°C for NaHSO4 solutions.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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