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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Engineering with computers 12 (1996), S. 144-154 
    ISSN: 1435-5663
    Keywords: Automatic mesh generation ; Mesh control ; Mapped meshing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract This paper presents generated enhancements for robust ‘two and three-quarter dimensional meshing’, including: (1) automated interval assignment by integer programming for submapped surfaces and volumes, (2) surface submapping, and (3) volume submapping. An introduction to the simplex method, an optimization technique of integer programming, is presented. Simplification of complex geometry is required for the formulation of the integer programming problem. A method of ‘i-j unfolding’ is defined which explains how irregular geometry can be realigned into a simplified form that is suitable for submap interval assignment solutions. Also presented is the processes by which submapping eliminates the decomposition of surface geometry, through a pseudodecomposition process, producing suitable mapped meshes. The process of submapping involves the creation of ‘interpolated virtual edges’, user defined ‘vertex types’ and ‘i-j-k space’ traversals. The creation of ‘interpolated virtual edges’ is the method by which submapping automatically subdivides surface geometry. The ‘interpolated virtual edge’ is formulated according to an interpolation scheme using the node discretization of curves on the surface. User defined ‘vertex types’ allow direct user control of surface decomposition and interval assignment by modifying ‘i-j-k space’ traversals. Volume submapping takes the geometry decomposition to a higher level by using ‘mapped virtual surfaces’ to eliminate decomposition of complex volumes.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of environmental contamination and toxicology 19 (1990), S. 190-196 
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Twelve workers were monitored for exposure to 18.75% lindane dust formulation during manual wheat seed treatment. The mean total actual exposure rate was 32.89 mg/hr. Potential respiratory exposure averaged 0.0057 mg/hr (〈1% of the total), with seven workers receiving no measurable respiratory exposures. Mean hand exposure was 1.84 mg/hr (5.6%). Dermal exposure to the head and neck averaged 4.28 mg/hr (13%). Exposure measured beneath the workshirt and workpants averaged 26.8 mg/hr (81.4%). The workshirt and workpants provided 3.4-fold and 11.5-fold protection factors, respectively. Forearm exposure measured beneath the workshirt represented more than 40% of total actual exposure. The small contribution of hand exposure to total dermal exposure was consistent with the use of chemical-resistant gloves by all workers. Total dermal exposure could be reduced substantially by wearing coveralls over regular work clothing, and by the use of gauntlet-type gloves. It is recommended that worker education concerning personal hygiene and the appropriate use of protection clothing be made essential components of exposure reduction programs.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1617-4623
    Keywords: Key words Adenine phosphoribosyl transferase ; Cytokinins ; Arabidopsis thaliana ; Mutant ; Male sterility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four mutants of Arabidopsis thaliana that are deficient in adenine phosphoribosyl transferase (APRT) activity have been isolated by selecting for germination of seeds and growth of the plantlets on a medium containing 2,6-diaminopurine (DAP), a toxic analog of adenine. In all mutants, DAP resistance is due to a recessive nuclear mutation at a locus designated apt. The mutants are male sterile due to pollen abortion after meiosis. Furthermore, it has been shown that metabolism of cytokinins is impaired in the mutant BM3, which has the lowest level of APRT activity among the mutants tested. However, three different cDNAs encoding APRT have been isolated in A. thaliana and this raised the question of the nature of the mutation which results in low APRT activity. The mutation was genetically mapped to chromosome I and lies within 6 cM of the phenotypic marker dis2, indicating that the mutation affects the APT1 gene, a result confirmed by sequencing of mutant alleles. The mutation in the allele apt1-3 is located at the 5′ splicing site of the third intron, and eliminates a BstNI restriction site, as verified by Southern blotting and PCR fragment length analysis.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Engineering with computers 12 (1996), S. 143-143 
    ISSN: 1435-5663
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Engineering with computers 13 (1997), S. 35-47 
    ISSN: 1435-5663
    Keywords: Hexahedral mesh generation ; Mesh refinement ; Plastering ; Whisker Weaving
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The spatial twist continuum (STC) is a powerful extension of the dual of a hexahedral mesh Murdochet al.,Int. J. Numer. Math. Engng (submitted). The STC captures the global connectivity constraints inherent in hexahedral meshing. Whisker wwaving is an advancing-front type of algorithm based on the STC[Tautges et al., Int. J. Numer. Math. Engng (submitted]. During the whisker weaving algorithm, certain types of degenerate elements calledwedges [Biacker; Myers (1993)Engng with Computers 9, 83–93 arise. This paper describedwedges and how they are formed, and presentscollapsing anddriving, two strategies for removing these degeneracies.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Engineering with computers 9 (1993), S. 83-93 
    ISSN: 1435-5663
    Keywords: Mesh generation ; Plastering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract This paper describes mesh correction techniques necessary for meshing an arbitrary volume with a completely hexahedral mesh. Specifically, it describes seams and wedges, mechanisms that overcome major hurdles encountered in the preliminary work on the plastering algorithm. The plastering algorithm iteratively projects layers of elements inward from a quadrilateral discretization of the volume's bounding faces. Seams and wedges resolve incompatibilities in the mesh and in the progressing boundary, thus ensuring the correct formation of a hexahedral mesh from the plastering algorithm.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1-12 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 2,7-diazapyrenium group (DAP2+) combines the features of pyrene, of methylviologen, and of nucleicacid intercalators and may thus present a variety of interesting properties. The cations 1 and 2 and the bis-diazapyrenium species 3 have been synthesized and shown to bind molecular anions like aromatic polycarboxylates, giving rise to pronounced shifts of 1H-NMR signals, modifications of UV/VIS absorption spectra, and quenching of fluorescence. The complexes formed probably have a face-to-face structure, and their stability constants are remarkably high, in particular for the bis-diazapyrenium cation 3 which is susceptible to form intercalative chelate complexes such as 9(log Ks ≈ 3 for 1, up to ca. 7 or more for 3a). Neutral molecules like adenine are also bound, but much less strongly. Visible-light irradiation of Me2DAP2+ (1) in presence of various electron donors, such as EDTA, gives the reduced species Me2DAP+ wich has been characterized by UV/VIS and ESR spectroscopy. The results indicate that Me2DAP2+ (1) functions as a methylviologen analogue, photoactive in visible light. Thus 2,7-diazapyrenium cations are attractive subunits for incorporation into macropolycyclic structures to give photo- and electroactive receptor molecules.
    Additional Material: 4 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1995-1999 
    ISSN: 0887-624X
    Keywords: poly-γ-D-glutamic acid ; biopolymer ; covalent modification ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methods for the covalent modification in aqueous solution of poly-γ-D-glutamic acid from Bacillus licheniformis have been studied. Co-derivatization of a synthetic UV-absorbent amine and ethanolamine, using a water-soluble carbodi-imide coupling agent, yielded a water-soluble modified polymer. Derivatization of the polymer was accompanied by cleavage of the γ-linked polypeptide backbone, and a reduction in molecular mass from 170 to 10 kDa. A procedure was developed for the removal of noncovalently bound ligands by treatment with 5 M CaCl2. The polymer sidechains also reacted in aqueous solution with p-nitrophenyl acetate to form covalent linkages. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 1995-1999, 1998
    Additional Material: 4 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 37 (1994), S. 517-536 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The superconvergent patch derivative recovery method of Zienkiewicz and Zhu is enhanced by adding the squares of the residuals of the equilibrium equation and natural boundary conditions. In addition, a new conjoint polynomial for interpolating the local patch stresses over the element which significantly improves the local projection scheme is presented. Results show that in the 4-node quadrilateral, the equilibrium and boundary condition residuals usually improve accuracy but not the rate of convergence, whereas in the 9-node quadrilateral, results are mixed. The conjoint polynomial always improves the accuracy of the derivative field within the element as compared to the standard nodal interpolation, particularly in 4-node quadrilaterals.
    Additional Material: 21 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 39 (1996), S. 1475-1489 
    ISSN: 0029-5981
    Keywords: meshing ; three-dimensional ; surfaces ; quadrilateral ; finite element ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper discusses the extension of the paving algorithm for all quadrilateral mesh generation to arbitrary three-dimensional trimmed surfaces. Methods of calculating angles, projecting elements, and detecting collisions between paving boundaries, for general surfaces are presented. Extensions of the smoothing algorithms for three dimensions are set forth. Advances in the use of scalar sizing functions are presented. These functions can be used to better approximate internal mesh density from boundary densities and surface characteristics.
    Additional Material: 16 Ill.
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