1,944 research outputs found
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Magnetostratigraphy of Equatorial Pacific Site 503 Hydraulic Piston Cores
The paleomagnetic measurement procedure at Site 503 was similar to that described for Site 502 (See preceding chapter). Each core section was measured with the longcore spinner magnetometer at 10-cm intervals. In addition, one or more discrete samples were taken from each core section for measurement of the total magnetic vector and its stability against progressive AF demagnetization. There were noteworthy differences in conditions at Site 503, however, that affected the quality and interpretation of the magnetic data and require comment
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High resolution magnetostratigraphy of Caribbean Plio-Pleistocene deep-sea sediments
The ability of the hydraulic piston corer (HPC) to recover virtually undisturbed sections of semi-consolidated deep-sea sediments suitable for paleomagnetic study was first demonstrated on Leg 64 and Leg 68 of the Glomar Challenger. Reported here is a complete magnetostratigraphy for a 150 m section of Plio-Pleistocene pelagic deposits recovered at Site 502 in the Caribbean. Correlation of the magnetic polarity zones to the well-dated standard sequence of geomagnetic polarity reversals provides a precise geochronological framework for age-calibration of calcareous plankton fossil datums and which, combined with the moderate to high sedimentation rates (24–38 m/m.y.), present an opportunity to study paleoenvironmental variations in the Early Pleistocene and the Pliocene with a time control and resolution heretofore possible only in Late Pleistocene deep-sea sediment cores
Use of Simulation Methods of Wave Processes for Non-Destructive Testing of Concrete Products of Different Geometrical Size
Theoretical and experimental research of electrical responses under pulsed mechanical excitation of different size concrete products was carried out. Comparison of calculated and experimental data shows very close agreement. The obtained results will help to develop new opportunities to improve the method of non-destructive testing of concrete by creating a bank of calculated electrical responses from products of different geometrical arrangement and elastic response and using them as standard samples for defectiveness evaluation of products according to previously established criteria
The Relationship Between the Parameters of the Electric and the Acoustic Signal with the Destruction of Concrete Under Cyclic Freeze-Thaw
The paper presents the research results of the effect of formation crack process on the parameters of the electric and acoustic response to impact excitation. The physical basis of mechanoelectric transformations is described. It was found that with increasing number of freeze-thaw cycles observed increase of the attenuation coefficient of energy of the electric and acoustic response by a linear relationship. Differences in the dynamics of change of attenuation coefficient of energy of the electric and acoustic response associated with differences in formation and registration of electric and acoustic response
Hierarchical Assembly of a Micro- and Macroporous Hydrogen-Bonded Organic Framework with Tailored Single-Crystal Size
Porous organic molecular materials represent an emergent field of research in Chemistry and Materials Science due to their unique combination of properties. To enhance their performance and expand the number of applications, the incorporation of hierarchical porosity is required, as exclusive microporosity entails several limitations. However, the integration of macropores in porous organic molecular materials is still an outstanding challenge. Herein, we report the first example of a hydrogen-bonded organic framework (MM-TPY) with hierarchical skeletal morphology, containing stable micro- and macroporosity. The crystal size, from micro to centimetre scale, can be controlled in a single step without using additives or templates. The mechanism of assembly during the crystal formation is compatible with a skeletal crystal growth. As proof of concept, we employed the hierarchical porosity as a platform for the dual, sequential and selective co-recognition of molecular species and microparticles.J.F.-S. thanks “Ramón y Cajal“ program (RYC2019-02794-I), MINECO (Spain) (Projects PID2019−104778GB−I00 and Excellence Unit “Maria de Maeztu” CEX2019−000919−M) and Generalitat Valenciana (SEJI/2020/034). E.V.R.F. thanks Ministerio de Ciencia e innovación (PID2020-116998RB-I00) and Ministerio de Educación y Formación Profesional (PRX21/00407)
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Site 503: Eastern Equatorial Pacific
Our primary objective at Site 503 (Fig. 1) was to re- cover a complete, undisturbed Neogene and Quaternary section in the eastern equatorial Pacific. Site 503 is located near Site 83 in an area that contains an almost continuous pelagic record of the past 10 m.y. (Hays et al., 1972). Unfortunately, Site 83 was only spot-cored, and the recovered sediment is so badly disturbed by rotary drilling that most of the detailed record is lost. The section has an average sedimentation rate of 2.0 to 2.5 cm/k.y. with good-to-moderate preservation of all the major microfossil groups. We returned to Site 83 to core the same section, using the Hydraulic Piston Corer (HPC) to obtain an undisturbed, continuous section for high-resolution stratigraphic studies
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Site 502: Colombia Basin, Western Caribbean
Our specific objective at Site 502 was to recover an undisturbed, complete section that could be used as a Neogene and Quaternary reference section. A complete record such as this would allow intercorrelations between (1) paleomagnetic stratigraphy, (2) calcareous biostratigraphy, (3) cyclic accumulation of sediment, (4) paleoceanographic changes, (5) oxygen and carbon isotope stratigraphies, (6) the chronology of Central American volcanism, (7) the timing and effects of the emergence of the Isthmus of Panama, and (8) the timing and effects of the initiation of Northern Hemisphere glaciation
Long-lived non-equilibrium superconductivity in a non-centrosymmetric Rashba semiconductor
We report non-equilibrium magnetodynamics in the Rashba-superconductor GeTe,
which lacks inversion symmetry in the bulk. We find that at low temperature the
system exhibits a non-equilibrium state, which decays on time scales that
exceed conventional electronic scattering times by many orders of magnitude.
This reveals a non-equilibrium magnetoresponse that is asymmetric under
magnetic field reversal and, strikingly, induces a non-equilibrium
superconducting state distinct from the equilibrium one. We develop a model of
a Rashba system where non-equilibrium configurations relax on a finite
timescale which captures the qualitative features of the data. We also obtain
evidence for the slow dynamics in another non-superconducting Rashba system.
Our work provides novel insights into the dynamics of non-centrosymmetric
superconductors and Rashba systems in general
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