High-resolution pursuit for detecting flaw echoes close to the material surface in ultrasonic NDT

2006 ◽  
Vol 39 (6) ◽  
pp. 487-492 ◽  
Author(s):  
N. Ruiz-Reyes ◽  
P. Vera-Candeas ◽  
J. Curpián-Alonso ◽  
J.C. Cuevas-Martínez ◽  
J.L. Blanco-Claraco
2019 ◽  
Author(s):  
Carolina Chávez-Madero ◽  
María Díaz de León-Derby ◽  
Mohamadmahdi Samandari ◽  
Carlos Fernando Ceballos-González ◽  
Edna Johana Bolívar-Monsalve ◽  
...  

AbstractThis paper introduces the concept of continuous chaotic printing, i.e., the use of chaotic flows for deterministic and continuous fabrication of fibers with internal multilayered micro-or nanostructures. Two free-flowing materials are coextruded through a printhead containing a miniaturized Kenics static mixer (KSM) composed of multiple helicoidal elements. This produces a fiber with a well-defined internal multilayer microarchitecture at high speeds (>1.0 m min-1). The number of mixing elements and the printhead diameter determine the number and thickness of the internal lamellae, which are generated according to successive bifurcations that yield a vast amount of inter-material surface area (~102 cm2 cm3) and high resolution features (~10 μm). In an exciting further development, we demonstrate a scale-down of the microstructure by 3 orders of magnitude, to the nanoscale level (~10 nm), by feeding the output of a continuous chaotic 3D printhead into an electrospinner. Comparison of experimental and computational results demonstrates the robust and predictable output and performance of continuous chaotic 3D printing. The simplicity and high resolution of continuous chaotic printing strongly supports its potential use in novel applications, including—but not limited to—bioprinting of multi-scale tissue-like structures, modeling of bacterial communities, and fabrication of smart multi-material and multilayered constructs.


2020 ◽  
Author(s):  
Valérie Baumann ◽  
Marc-Henri Derron ◽  
Jean-Luc Epard ◽  
Michel Jaboyedoff

<p>The main goal of this project is to harmonise the different geological maps (scale 1:25.000) and to improve the Quaternary mapping of the region of “canton de Vaud” in Switzerland using a high resolution LiDAR digital elevation model, and geophysical or boreholes data. We present here the results for the geologic mapping of two test areas: one in the Prealps and the second in the Molasse Plateau.</p><p>Detailed geological maps (scale 1:25.000) have been produced during the XX century for the whole region. During the last Late Glacial Maximum (LGM) the canton de Vaud area was covered by ice sheets, then soils and loose rock deposits were formed toward the end of ice age, however the Quaternary formations are sometimes not represented especially when their thickness is only of a few meters and the interpretation of geomorphologic features with aerial photographs was difficult in areas covered by forest.  </p><p>In recent years, the high-resolution digital elevation model derived from high resolution LiDAR data with the possibility to remove the trees in the forested areas offers the possibility to detect and interpret new morphologies.</p><p>In this study, different LIDAR-derived hillshade maps have been used to improve the delimitation of bedrock and Quaternary formation through morphological feature analyse. Borehole data gave us fundamental data about geology and stratigraphy and field surveys were performed for selected places. Additionally, a terrain classification system first developed in Canada (Cruden and Thomson, 1987) was used to add information for each polygon like genetic material, surface expression, modifying processes and stratigraphic data. All the mapping was performed in a GIS (Geographic system information) environment.</p><p>Detailed bedrock and Quaternary mapping will provide very good information for the management of the resources, land planning and geo-hazards. The additional information (terrain classification) for each polygon allow us to create different thematic maps starting from the geological map.</p><p> </p><p>Reference:</p><p> Cruden, D. M., and S. Thomson. Exercises in terrain analysis. Pica Pica Press, 1987.</p><p> </p>


1967 ◽  
Vol 31 ◽  
pp. 45-46
Author(s):  
Carl Heiles

High-resolution 21-cm line observations in a region aroundlII= 120°,b11= +15°, have revealed four types of structure in the interstellar hydrogen: a smooth background, large sheets of density 2 atoms cm-3, clouds occurring mostly in groups, and ‘Cloudlets’ of a few solar masses and a few parsecs in size; the velocity dispersion in the Cloudlets is only 1 km/sec. Strong temperature variations in the gas are in evidence.


2019 ◽  
Vol 42 ◽  
Author(s):  
J. Alfredo Blakeley-Ruiz ◽  
Carlee S. McClintock ◽  
Ralph Lydic ◽  
Helen A. Baghdoyan ◽  
James J. Choo ◽  
...  

Abstract The Hooks et al. review of microbiota-gut-brain (MGB) literature provides a constructive criticism of the general approaches encompassing MGB research. This commentary extends their review by: (a) highlighting capabilities of advanced systems-biology “-omics” techniques for microbiome research and (b) recommending that combining these high-resolution techniques with intervention-based experimental design may be the path forward for future MGB research.


1994 ◽  
Vol 144 ◽  
pp. 593-596
Author(s):  
O. Bouchard ◽  
S. Koutchmy ◽  
L. November ◽  
J.-C. Vial ◽  
J. B. Zirker

AbstractWe present the results of the analysis of a movie taken over a small field of view in the intermediate corona at a spatial resolution of 0.5“, a temporal resolution of 1 s and a spectral passband of 7 nm. These CCD observations were made at the prime focus of the 3.6 m aperture CFHT telescope during the 1991 total solar eclipse.


1994 ◽  
Vol 144 ◽  
pp. 541-547
Author(s):  
J. Sýkora ◽  
J. Rybák ◽  
P. Ambrož

AbstractHigh resolution images, obtained during July 11, 1991 total solar eclipse, allowed us to estimate the degree of solar corona polarization in the light of FeXIV 530.3 nm emission line and in the white light, as well. Very preliminary analysis reveals remarkable differences in the degree of polarization for both sets of data, particularly as for level of polarization and its distribution around the Sun’s limb.


1988 ◽  
Vol 102 ◽  
pp. 41
Author(s):  
E. Silver ◽  
C. Hailey ◽  
S. Labov ◽  
N. Madden ◽  
D. Landis ◽  
...  

The merits of microcalorimetry below 1°K for high resolution spectroscopy has become widely recognized on theoretical grounds. By combining the high efficiency, broadband spectral sensitivity of traditional photoelectric detectors with the high resolution capabilities characteristic of dispersive spectrometers, the microcalorimeter could potentially revolutionize spectroscopic measurements of astrophysical and laboratory plasmas. In actuality, however, the performance of prototype instruments has fallen short of theoretical predictions and practical detectors are still unavailable for use as laboratory and space-based instruments. These issues are currently being addressed by the new collaborative initiative between LLNL, LBL, U.C.I., U.C.B., and U.C.D.. Microcalorimeters of various types are being developed and tested at temperatures of 1.4, 0.3, and 0.1°K. These include monolithic devices made from NTD Germanium and composite configurations using sapphire substrates with temperature sensors fabricated from NTD Germanium, evaporative films of Germanium-Gold alloy, or material with superconducting transition edges. A new approache to low noise pulse counting electronics has been developed that allows the ultimate speed of the device to be determined solely by the detector thermal response and geometry. Our laboratory studies of the thermal and resistive properties of these and other candidate materials should enable us to characterize the pulse shape and subsequently predict the ultimate performance. We are building a compact adiabatic demagnetization refrigerator for conveniently reaching 0.1°K in the laboratory and for use in future satellite-borne missions. A description of this instrument together with results from our most recent experiments will be presented.


Author(s):  
Robert M. Glaeser

It is well known that a large flux of electrons must pass through a specimen in order to obtain a high resolution image while a smaller particle flux is satisfactory for a low resolution image. The minimum particle flux that is required depends upon the contrast in the image and the signal-to-noise (S/N) ratio at which the data are considered acceptable. For a given S/N associated with statistical fluxtuations, the relationship between contrast and “counting statistics” is s131_eqn1, where C = contrast; r2 is the area of a picture element corresponding to the resolution, r; N is the number of electrons incident per unit area of the specimen; f is the fraction of electrons that contribute to formation of the image, relative to the total number of electrons incident upon the object.


Author(s):  
Glen B. Haydon

Analysis of light optical diffraction patterns produced by electron micrographs can easily lead to much nonsense. Such diffraction patterns are referred to as optical transforms and are compared with transforms produced by a variety of mathematical manipulations. In the use of light optical diffraction patterns to study periodicities in macromolecular ultrastructures, a number of potential pitfalls have been rediscovered. The limitations apply to the formation of the electron micrograph as well as its analysis.(1) The high resolution electron micrograph is itself a complex diffraction pattern resulting from the specimen, its stain, and its supporting substrate. Cowley and Moodie (Proc. Phys. Soc. B, LXX 497, 1957) demonstrated changing image patterns with changes in focus. Similar defocus images have been subjected to further light optical diffraction analysis.


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