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  • 1
    Electronic Resource
    Electronic Resource
    Evanescent Electromagnetics: A Novel, Super-Resolution, and Non-Intrusive, Imaging Technique for Biological Applications (1999)
    Springer
    Biomedical microdevices 2 (1999), S. 73-80 
    Details
    ISSN: 1572-8781
    Keywords: nondestructive testing ; evanescent microwave imaging ; quantitative testing ; conductivity in biomaterials ; high resolution imaging ; material non-uniformity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Scanning tunneling and atomic force microscopes (STM and AFM) are used to study biological materials. These methods, often capable of achieving atomic resolutions, reveal fascinating information regarding the inner workings of these materials. However, both STM and AFM require physical contact to the specimen. In the case of STM, the specimen needs to be conducting as well. Here we introduce a new method for imaging biological materials through air or a suitable liquid using decaying or evanescent fields at the tip of a properly designed microwave resonator. This novel method involves the use of an evanescent microwave probe (EMP) and is capable of imaging a variety of non-uniformities in biological materials including conductivity, permittivity, and density variations. EMP is a non-contact and non-destructive sensor and it does not require conducting specimens. Its spatial resolution is currently around 0.4 μm at 1 GHz. We have used this probe to map non-uniformities in a variety of materials including metals, semiconductors, insulators, and biological and botanical samples. Here we discuss applications of EMP imaging in bone, teeth, botanical, and agricultural specimens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009911417776
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  • 2
    Electronic Resource
    Electronic Resource
    Image shifting for PIV using birefringent and ferroelectric liquid crystals (1996)
    Springer
    Experiments in fluids 21 (1996), S. 341-346 
    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 This paper discusses a new implementation of electrooptical image shifting, used to resolve directional ambiguity in particle image velocimetry (PIV) measurements. The setup uses a ferroelectric liquid crystal (FLC) as a polarization rotator and a birefringent calcite plate as a shifter. The system can be used with non-polarized light sources and fluorescent particles. The minimum shifting time (pulse separation) is approximately 100 μs. This compact electrooptical device is usually positioned in front of the camera lens, though it has also been mounted inside the lens body. Sample vector maps from a turbulent multidirectional flow are included.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00189054
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  • 3
    Electronic Resource
    Electronic Resource
    Turbulent flow measurement in a square duct with hybrid holographic PIV (1997)
    Springer
    Experiments in fluids 23 (1997), S. 373-381 
    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 hybrid holographic system has been developed for three-dimensional particle image velocimetry. With unique high pass filters, the system combines advantages of both in-line and off-axis holography without having their draw-backs. It improves the signal to noise ratio of the reconstructed image, allows use of 3–15 μm particles in water at high population and achieves large dynamic ranges in both velocity and space. With an automated image acquisition and processing system it has been used for measuring the velocity distributions in a square duct at Re=1.23×105. The data consists of 97×97×87 vectors (with 50% overlapping of adjacent interrogation windows). The quality of the results is evaluated using the continuity equation. The deviation from the equation decreases rapidly with increasing control volume and reaches a level of less than 10%. Mean velocities, r.m.s. velocity fluctuations and turbulence spectra are estimated using the data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003480050124
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  • 4
    Electronic Resource
    Electronic Resource
    The Ptolemaic gamma-ray burst universe (1992)
    Springer
    Astrophysics and space science 197 (1992), S. 163-168 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The BATSE experiment on GRO has demonstrated the isotropic arrival directions and flad logN vs logS of cosmic gamma-ray bursts. These data are best explained if the burst sources are distributed throughout an extended spherical galactic halo, as previously suggested by Jennings. The halo's radius is at least 40 kpc, and probably is more than 100 kpc. I consider possible origins of this halo, including primordial formation and neutron stars recoiling from their birthplaces in the galactic disc A simple geometrical model leads to a predicted relation between the dipole and quadrupole anisotropy. I suggest that neutron stars born with low recoil become millisecond publsars, while those born with high recoil become the sources of gamma-ray bursts; these populations are nearly disjoint. Quiescent counterparts of gamma-ray bursts are predicted to be undetectably faint.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00645080
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  • 5
    Electronic Resource
    Electronic Resource
    Failure of magnetic fields to explain rotation curves of spiral galaxies (1994)
    Springer
    Astrophysics and space science 213 (1994), S. 155-156 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00627787
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  • 6
    Electronic Resource
    Electronic Resource
    Theory of microwave interactions in ceramic materials: the phenomenon of thermal runaway (1991)
    Springer
    Journal of materials science 26 (1991), S. 2483-2489 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A theory of the phenomenon of thermal runaway in ceramic materials undergoing microwave heating is presented on the basis of a simple temperature-time equation. The non-linear evolution inherent in the equation is shown to arise naturally from physical arguments and it is shown how the parameters of the theory may be calculated from the microscopic absorption processes and information about the material under consideration. The theory is applied to experimental observations reported on several different materials and shown to be in good agreement with the data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01130199
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  • 7
    Electronic Resource
    Electronic Resource
    Microwave and conventional sintering of rapidly solidified Al2O3-ZrO2 powders (1994)
    Springer
    Journal of materials science 29 (1994), S. 2119-2125 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The Al2O3-ZrO2 eutectic composition was rapidly solidified, forming amorphous and crystalline structures. The as-quenched material was crushed and pressed into pellets which were sintered conventionally or with microwaves. Conventional and microwave sintering at temperatures up to 1600 °C resulted in a microstructure where 100–200 nm ZrO2 grains were present intergranularly in the α-Al2O3 grains. Larger ZrO2 grains (∼1 μm) were found intergranularly. The as-quenched lamellar structure spheroidized during sintering at high temperatures. Boron contamination of the powders resulted in more homogeneous and dense as-fired samples but promoted the ZrO2 tetragonal-to-monoclinic transformation, which was attributed to increased grain boundary diffusivity. Conventional sintering at low temperatures resulted in the formation of “rods” of an Al2O3-rich phase which grew from a low-melting B2O3-rich liquid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01154689
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  • 8
    Electronic Resource
    Electronic Resource
    Microwave densification of electrophoretically infiltrated silicon carbide composite (1997)
    Springer
    Journal of materials science 32 (1997), S. 6429-6433 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A new method to fabricate SiC composites by microwave heating SiC preforms is described. Preforms were produced by electrophoretically infiltrating SiC fibre (Nicalon) preforms with SiC powder. Samples were heated to 1600°C in a matter of minutes and held at temperature for 5 min to minimize fibre degradation. To achieve densification, heated preforms required the application of a uniform load. Bulk densities increased from ∼ 0.8 gcm-3 for the as-infiltrated preforms to over 1.9 gcm-3 for microwave-heated samples with a small applied load of ∼13 kPa. Microstructural analysis revealed the presence of some pores and cracks in the matrix; however, large areas of dense SiC matrix material are apparent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018634521493
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  • 9
    Electronic Resource
    Electronic Resource
    A generalized method for characterizing elastic anisotropy in solid living tissues (1990)
    Springer
    Journal of materials science 1 (1990), S. 1-8 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract The microstructure of cortical bone may exhibit either transverse isotropic or orthotropic symmetry, thus requiring either five or nine independent elastic stiffness coefficients (or compliances), respectively, to describe its elastic anisotropy. Our previous analysis to describe this anisotropy in terms of two scalar quantities for the transverse isotropic case is extended here to include orthotropic symmetry. The new results for orthotropic symmetry are compared with previous calculations using the transverse isotropic analysis on the same sets of anisotropic elastic constants for bone, determined either by mechanical or by ultrasonic experiments. In addition, the orthotropic calculation has been applied to full sets of orthotropic elastic stiffness coefficients of a large variety of wood species. Although having some resemblance to plexiform bone in microstructural organization, there is a dramatic difference in both the shear and the compressive elastic anisotropy between the two materials: wood is at least one order of magnitude more anisotropic than bone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00705346
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  • 10
    Electronic Resource
    Electronic Resource
    How much is a collaboration worth? A calibrated bibliometric model (1997)
    Springer
    Scientometrics 40 (1997), S. 541-554 
    Details
    ISSN: 1588-2861
    Source: Springer Online Journal Archives 1860-2000
    Topics: Information Science and Librarianship , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract Interest in collaboration is increasing in policy circles. There are numerous international and national programs to encourage collaboration, for example, between university and industry researchers. However, little is know about the way in which collaboration changes the impact of a research publication. This paper explores how the impact (average citations per paper) varies with different types of collaboration. A calibrated bibliometric model is derived that demonstrates that collaborating with an author from the home institution or another domestic institution increases the average impact by approximately 0.75 citations while collaborating with an author from a foreign institution increases the impact by about 1.6 citations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02459299
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