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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 803-805 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reduction of δ-hydroxy-β-ketoesters 1 was investigated with three different reducing agents. In several instances, high selectivity in favor of syn-1,3-diols was observed.
    Additional Material: 2 Tab.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989), S. 773-790 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An analysis of the pathways and intermediates for the epoxidation of olefins using a Ru(IV)-oxo model complex is presented. Simple bonding concepts, coupled with INDO/1 semiempirical MO calculations, provide a description of the metal-oxo/olefin interaction that agrees well with experimental facts. Concerted [1 + 2] and [2 + 2] pathways are investigated and found to lead to unfavorable orbital interactions as with organic analogues. Nonconcerted process (those in which one bond is formed before the second), which connect the two concerted pathways, are preferred. A nonconcerted [1 + 2] pathway is preferred over a nonconcerted [2 + 2] pathway on the basis of less steric repulsions between the olefin and the metal ligands. Also, all open structures (those with one C—O bond formed) investigated minimized to bound epoxides. In the most favorable pathway, a nonconcerted [1 + 2] pathway, radical cation character on the terminal carbon increases as the nonconcerted process is induced. Preference for the bound epoxide intermediate over the oxometallocycle is simply explained by partial charge considerations.
    Additional Material: 7 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 38 (1990), S. 665-678 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The INDO/1 semi-empirical method is used to analyze the hydroxylation of alkanes by models for the putative active species in cytochromes P-450. In the insertion of oxygen into the C—H bond by a M - O complex there are four atoms of particular interest, the metal and oxygen atoms of the oxidant plus the C and H atom of the C—H bond to be activated. With four atoms being studied (3N-6=), 6 degrees of freedom need to be described and a nearly intractable computational problem results. Thus, two reaction coordinates (CHI and OAT) were developed in an attempt to describe alkane hydroxylation in a chemically meaningful way. CHI (C—H insertion) is a measure of the extent to which the C—H bond has been activated and transferred to the O atom. OAT (oxygen atom transfer) is a measure of the extent to which the C—O bond in the alcohol product has formed. The models chosen for the present study are manganyl (MnO) and ferryl (FeO) porphyrin complexes. Experimental evidence for manganese prophyrin complexes shows that as the axial ligand is made a stronger donor the insertion of the O atom into the C—H bond becomes less concerted. The INDO/1 method was used to calculate the points on the PES determined by the changes in OAT and CHI. The results point to the axial ligand modifying the pathway by changing the relative electro-/nucleophilicity of the oxygen atom.
    Additional Material: 2 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 7 (1973), S. 537-543 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Numerical solutions are presented for the problem of minimum weight design of a thin one-dimensiona simply-supported, solid panel in compression with one side exposed to a parallel high supersonic air flow. The flutter speed is held fixed, and a minimum thickness constraint is imposed. In addition, a multiplier technique is incorporated into the discrete variable minimization process to improve the convergence speed.
    Additional Material: 2 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 950-953 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Large scale non-linear programming problems with non-linear constraints are of practical concern in the areas of process control and system design. Although advances in computer technology address these problems, more efficient algorithms are needed. An algorithm currently used is Rosen's Gradient Projection Method. This note presents an alternative technique of performing the steps for finding the projected gradient used in Rosen's method, a technique that gives equivalent results with fewer computations.
    Additional Material: 1 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 30 (1996), S. 165-174 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Ion beam technology may be applied in a straightforward fashion to the analysis and modification of biomaterials. For analytical purposes, characterization using megaelectron-volt He2+ ions provides a standardless, nondestructive means for accurately quantifying the composition of material surfaces and the thickness of thin films. In this study, three complementary ion backscattering techniques were utilized to characterize hydroxyapatite (HA) films: Rutherford backscattering spectrometry (RBS) can determine composition and amounts of elements heavier than He; forward recoil elastic spectrometry (FRES) can determine hydrogen content; resonance-enhanced RBS can quantify small amounts of light elements, e.g. carbon, by choosing a particular incident beam energy resulting in excitation of the light element nucleus. At this resonance energy, the scattering cross section greatly increases, improving elemental sensitivity. Sol-gel chemistry was used to synthesize HA films by spin coating and annealing in a rapid thermal processor. Using these techniques, the chemical composition of unfired films was Ca1.63O5.4H1.8C0.24P with a thickness of 3.01 × 10 18 atoms/cm2 and after firing at 800°C as Ca1.66O4.0H0.26C0.09P with a thickness of 2.11 × 1018 atoms/cm2. This compares favorably to stoichiometric HA, which has a composition of Ca1.67O4.33H0.33P. © 1996 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 16 (1995), S. 216-226 
    ISSN: 0197-8462
    Keywords: job classification ; occupational exposure ; personal-exposure monitoring ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The Electric and Magnetic Field Measurement Project for Utilities - the Electric Power Research Institute (EPRI) Electric and Magnetic Field Digital Exposure (EMDEX) Project (the EPRI EMDEX Project) - was a multifaceted project that entailed technology transfer, measurement protocol design, data management, and exposure assessment analyses. This paper addresses one specific objective of the project: the collection, analysis, and documentation of power-frequency magnetic field exposures for a diverse population of utility workers. Field exposure data measured by an EMDEX system were collected by volunteer utility employees at 59 sites in four countries between September, 1988, and September, 1989. Specially designed sampling procedures and data collection protocols were used to ensure uniform implementation across sites. Volunteers within 13 job classifications recorded which of eight work or three nonwork environments they occupied while wearing an EMDEX meter. Approximately 50,000 hours of magnetic field exposure records taken at 10 s intervals were obtained, about 70% of which were from work environments. Exposures and time spent in environments were analyzed by primary work environment, by occupied environment, and by job classification. Generally, for utility-specific job classifications related to the generation, transmission, and distribution of electricity, the field and exposure measurements in terms of workday mean field were higher than in more general occupations. The job classifications with the highest (median workday mean) exposure were substation operators (0.7 μT) and electricians (0.5μT). Total variance also tended to be largest for utility-specific job classifications. For these workers, the contributions of between-worker and within-worker variances to total variance were about the same. Measurements in utility-specific environments were higher than in more general environments. Estimates of time-integrated exposure indicated that utility-specific job classifications received about one-half or more of their total exposure on the job. The nonwork field and exposure distributions for workers in all job categories were comparable with median nonworkday means of about 0.09 μT. © 1995 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 56 (1962), S. 267-272 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Titanium tetrafluoride has been successfully employed in combination with triisobutyl aluminum (TBA) as a Ziegler type of catalyst to polymerize butadiene. The resulting polymer has a higher cis to trans ratio and a higher degree of crosslinking than one prepared with the titanium tetrachloride-TBA catalyst. It is of interest that vinyl chloride, a monomer containing a donor atom, was polymerized with the TiF4-TBA catalyst. Titanium tetrafluoride is not a very effective catalyst for the Friedel-Crafts type of reactions.
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  • 9
    Electronic Resource
    Electronic Resource
    Brookfield, Conn. : Wiley-Blackwell
    Journal of Vinyl and Additive Technology 16 (1994), S. 181-186 
    ISSN: 0193-7197
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new process system began operation at the Eaglebrook Plastics, Inc. facility in January 1992 that provides automated identification and separation of postconsumer plastic bottles and containers derived from baled and whole bottle sources. Since that time a number of these automated separation systems have been installed, and are in operation. This paper describes automated plastic separation systems that are currently in operation, provides operating data from the plants, and discusses advances in plastic separation methods currently under development.
    Additional Material: 4 Ill.
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  • 10
    ISSN: 0197-8462
    Keywords: exposure indices ; epidemiology ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Power-frequency electric and magnetic fields are known to exhibit marked temporal variation, yet in the absence of clear biological indications, the most appropriate summary indices for use in epidemiologic studies are unknown. In order to assess the statistical patterns among candidate indices, data on 4383 worker-days for magnetic fields and 2082 worker-days for electric fields collected for the Electric and Magnetic Field Project for Electric Utilities using the EMDEX meter [Bracken (1990): Palo Alto, CA: Electric Power Research Institute] were analyzed. We examined correlations at the individual and job title group levels among indices of exposure to both electric and magnetic fields, including the arithmetic mean, geometric mean, median, 20th and 90th percentiles, time above lower cutoffs of 20 V/m and 0.2 μT, and time above higher cutoffs of 100 V/m and 2.0 μT. For both electric and magnetic fields, the arithmetic mean was highly correlated with the 90th percentile; moderately correlated with the geometric mean, median, and lower and higher cutoff scores; and weakly correlated with the 20th percentile. Electric and magnetic field indices were generally weakly correlated with one another. Rank-order correlation coefficients were consistently greater than product-moment correlation coefficients. Job title group summary scores showed higher correlations among electric field indices and magnetic field indices and between electric and magnetic field indices than was found for individual worker-days, with only the 20th percentile clearly independent of the others. These results suggest that individuals' exposures are adequately characterized by a measure of central tendency for electric and magnetic fields, such as the arithmetic or geometric mean, and an indicator of a lower threshold or cutoff for each field type, such as the 20th percentile or proportion of time above 20 V/m or 0.2 μT. A single measure of central tendency for each type of field appears to be adequate when exposures are assessed at the job title level. © 1994 Wiley-Liss, Inc.
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