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  • NDE  (5)
  • Polymer and Materials Science  (3)
  • Cell & Developmental Biology  (2)
  • 1
    Electronic Resource
    Electronic Resource
    The relationship between radiating body forces and equivalent surface stresses: Analysis and application to EMAT design (1980)
    Springer
    Journal of nondestructive evaluation 1 (1980), S. 79-85 
    Details
    ISSN: 1573-4862
    Keywords: ultrasonic waves ; EMAT ; surface stress ; NDE ; Green's function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract An analysis of the radiation from a body force shows that it is equivalent to the radiation from a series of surface stresses defined by the moments of the body force taken with respect to the depth coordinate. As the body force becomes localized near the surface, the zeroth moment of the force dominates the radiation and is often thought of as an equivalent surface stress. However, under certain conditions, this can vanish, and the other moments must be considered. It is found that, as the order of the moment of a particular force component increases, the resulting radiation patterns alternate between those characteristic of a compressive surface stress and those characteristic of a shear surface stress, which have considerably different angular variations. Results of experiments in the development of EMAT transducers for nondestructive testing that support these results are cited, and important consequences in the design of inspection systems are indicated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00566116
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  • 2
    Electronic Resource
    Electronic Resource
    Quantitative characterization of flaws near a surface using inverse born approximation (1982)
    Springer
    Journal of nondestructive evaluation 3 (1982), S. 183-188 
    Details
    ISSN: 1573-4862
    Keywords: Ultrasonics ; Born inversion ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Quantitative reconstruction of volumetric flaws near a surface of an elastic solid has been carried out experimentally by analyzing the scattered ultrasonic waves. The inverse Born approximation (developed for flaws in bulk materials) was tested for the first time in the determination of the size, shape, and orientation of near-surface flaws. We have studied spherical solid inclusions at various depths below the surface. In addition we examined an approximately 2:1 prolate spheroidal inclusion which was located one major axis below the surface. The determination of the flaw's size, shape, and orientation in terms of an equivalent ellipsoid is realized by performing nonlinear least-squares iteration of the one-dimensional Born inversion results obtained at various scattering directions within a finite aperture. The reconstruction is in good agreement with the actual parameters of the flaw.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00565863
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  • 3
    Electronic Resource
    Electronic Resource
    The interaction of ultrasound with contacting asperities: Applications to crack closure and fatigue crack growth (1984)
    Springer
    Journal of nondestructive evaluation 4 (1984), S. 203-212 
    Details
    ISSN: 1573-4862
    Keywords: Acoustic diffraction ; acoustic transmission ; asperity contact ; crack closure ; fatigue cracks ; mode conversion ; NDE ; stress intensity factor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The partial contact of two rough fatigue crack surfaces leads to transmission, reflection, diffraction, and mode conversion of an acoustic signal at those contacts. This paper reviews recent experimental and theoretical efforts to understand and quantify such contact on actual fatigue cracks in greater detail. It is shown that the size and density of individual contacts, or asperities, can be estimated from acoustic measurements. Furthermore, it is shown that this information is useful to provide the static stress across a partially closed crack as well as the “effective” stress intensity range which activates fatigue crack propagation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00566225
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  • 4
    Electronic Resource
    Electronic Resource
    The effects of focusing and refraction on Gaussian ultrasonic beams (1984)
    Springer
    Journal of nondestructive evaluation 4 (1984), S. 107-123 
    Details
    ISSN: 1573-4862
    Keywords: ultrasonics ; transducers ; focusing ; refractior ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A scalar theory of the propagation of Gaussian ultrasonic beams through lenses and interfaces is presented. For radiation into a fluid, the Fresnel approximation is employed to derive the laws of propagation of Guassian beams (previously employed in the analysis of coherent optical systems). These are then generalized to situations commonly found in nondestructive evaluation by treating the effects of propagation through lenses and through curved interfaces at oblique incidence. A numerical example illustrates the ease with which insight into diffraction phenomena for complex geometries can be gained by this approach. The limitations imposed on the theory by aberrations and the scalar assumption are discussed, and the relationship of the Gaussian theory to the radiation of piston transducers is explored.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00566401
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  • 5
    Electronic Resource
    Electronic Resource
    Half-space radiation by EMATs (1980)
    Springer
    Journal of nondestructive evaluation 1 (1980), S. 157-181 
    Details
    ISSN: 1573-4862
    Keywords: EMAT ; radiation pattern ; transducer ; shear waves ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A Green's function calculation of the far-field radiation patterns of EMATs is presented. The approach is based on (a) closed form expressions for the eddy current and static magnetic field distributions, established by the EMATs, which react to produce the driving Lorentz forces, and (b) a Green's function derived from the steepest descent approximation to the far-field response of an arbitrary surface point force on a half space. Numerical results are presented, illustrating the radiation patterns of the three common EMAT designs. Included are vertically polarized shear waves as radiated by both meander coil and periodic magnet EMATs and horizontally polarized shear waves as radiated by the latter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00567089
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  • 6
    Electronic Resource
    Electronic Resource
    A circular dichroic investigation of the secondary structure of lectins (1978)
    New York : Wiley-Blackwell
    Biopolymers 17 (1978), S. 2107-2120 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The far-uv CD spectra of eight lectins are presented. These eight lectins, as well as others previously studied, are grouped into three classes according to their particular CD spectra. The eight lectins studied appeared to have secondary structure dominated by β-pleated sheet, which so far has been true of all lectins. An attempt was made to quantitate the three structural components (α-helix, β-pleated sheet, and aperiodic) in the lectins using the data for reference proteins given by Chen et al. [Biochemistry 13,3350 (1974)]. For lectins in two of the classes, this method proved excellent and values for the three components are given. However, for the third class of lectins, which includes most of the lectins as well as Concanavalin A, this method of analysis proved to be unsatisfactory. This inadequacy was due to two factors: (1) the reference proteins used by Chen and (2) the unusual CD spectra of these lectins manifested by considerable ellipticity above 225 nm in a region where there are no known peptide electronic transitions.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1978.360170906
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  • 7
    Electronic Resource
    Electronic Resource
    Basic dyeability and acid content of high-conversion polyacrylonitrile (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 3341-3351 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Previous data have shown that the basic dyeability of acrylic polymers increases at a given specific viscosity as the peroxydisulfate-to-bisulfite ratio, that is, the catalyst-toactivator (C/A) ratio, is increased. This study represents an effort to understand better the role of the initiator system on the basic dyeability, the acid group composition, and the chain composition of acrylic polymers by preparing model polymers with radioactive initiators. As the C/A ratio is increased, the molecular weight distribution broadens as measured by the M̄v/M̄n ratio, the latter obtained by osmometry. There is also a significant effect of both C/A ratio and molecular weight on the sulfate group content per molecule, but there is no effect of C/A ratio on the number of basic dye sites per molecule, the number of sulfonate groups per molecule, or the weak acid groups per molecule. These effects can be explained by invoking a chain transfer to activator reaction in addition to the usual method of chain termination by recombination. The basic dyeability is found to correlate with the number-average molecular weight and with the number of strong acid groups plus the nonchromophoric weak acid groups.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070161223
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  • 8
    Electronic Resource
    Electronic Resource
    Lectin histochemistry of the embryonic heart: Expression of terminal and penultimate galactose residues in developing rats and chicks (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 184 (1989), S. 85-94 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Rat embryos at days 10-18 of gestation and chicken embryos at days 3-6 of incubation were fixed and processed for lectin histochemistry. The distribution of binding sites for a lectin from the peanut Arachis hypogaea (PNA) conjugated to horseradish per-oxidase (HRP) was determined on tissue sections both before and after enzymatic cleavage of sialic acid with neuraminidase (sialidase). Endocardial cushion tissue in the rat, but not in the chick, reacted with PNA-HRP prior to digestion with sialidase. Endocardium of both species (12 and 13 days in rat, 5 and 6 days in chick), particularly at the level of endocardial cushions, reacted strongly with the sialidase-PNA sequence; this staining decreased markedly after day 14 of gestation in the rat. PNA binding sites capped by sialic acid were most abundant in the developing rat heart during the critical period of endocardial cushion formation and decreased as development proceeded. The marked changes in the appearance and distribution of cardiac cell and tissue glycoconjugates during cardiogenesis support the concept that rapid changes occur in the structure of complex carbohydrates during embryonic and fetal development. The findings also suggest that such glycosylation-related events may be species specific.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001840110
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  • 9
    Electronic Resource
    Electronic Resource
    Lectin histochemistry of the embryonic heart: Fucose-specific lectin binding sites in developing rats and chicks (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 184 (1989), S. 76-84 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Glycoconjugates, particularly their sugar side chains, play important roles in embryonic development. Changes in cell-surface-associated glyco-conjugates are known to affect cell differentiation, cellular interactions, and other developmental phenomena during embryogenesis. The embryonic heart goes through a series of complicated morphologic events during development. Of particular interest is morphogenesis of the outflow tract. This region of the embryonic heart originates from more than one cell population and undergoes a complex process of septation during formation of the great vessels. Histochemi-cal analysis with a series of fucose-specific lectins conjugated to horseradish peroxidase has revealed the presence of a fucosylated glycoconjugate in the outflow tract of the developing heart. The results reveal further that the expression of the fucosylated glycoconjugate is stage-dependent and thus probably genetically regulated. The timing and distribution of staining with the lectin OFA suggest that this fucosylated glycocoiyu-gate may play a role in directing the migration of neural crest cells into the heart and subsequent formation of the conus septum.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001840109
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  • 10
    Electronic Resource
    Electronic Resource
    GPC analysis of model compounds. I. Phenyl- and benzo-substituted aromatic compounds (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 8 (1970), S. 1165-1190 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of 36 compounds of known structure was used in a study to elucidate the mechanism of separation of gel-permeation chromatography (GPC). The various molecular dimensions were defined and measured for these compounds. The elution volume for these compounds was determined by GPC under specified and controlled conditions. The relationships between elution volume and molecular dimension were investigated using computer-based statistical analysis for the entire set of compounds and manual simultaneous equations for smaller sets of compounds. It was found that, as increasingly more molecular dimensions are considered, (1) the importance of the maximum molecular dimension Ap′ (the only dimension considered by many investigators) significantly decreases and (2) a significantly better prediction of the elution volume of these compounds could be made.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.150080511
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