6,350 research outputs found
Palynological PV borehole dataset
No full textQuantitative palynological data – proxy data – from the PV borehole (onshore Valdés Basin) together with the statistical treatment of data, offer key information for regional paleoclimatic, paleoenvironmental and paleogeomorphic reconstructions for the Miocene of the southwestern Atlantic Ocean. Data show the stratigraphical distribution of palynomorphs (number of specimens) and environmental variables of 60 samples from a 580 m-thick section. Quantitative changes in the palynological assemblages may indicate shifting of the coastline, related — in part – to fluctuations of the relative sea level and in turn, interpreted as successive regional transgressive - regressive cycles occurred during the Miocene in the southwestern Atlantic margin
Spatial Dataset for Suitability Modeling and Sensitivity Analysis for Biomass Energy Facilities in Turkey
No full textThis dataset contains various spatial data formatted with ESRI shapefile or TIFF for the Turkey study area. All data have the same projection system as EPSG 5637 TUREF/LCC Europe. The metadata of dataset is given below;
-Population Density, Turkish Statistical Institute, 2018,
-Estimated Biomass Energy, General Directorate of Energy Affairs, 2014,
-Slope, European Digital Elevation Model (EU-DEM), v 1.1, 2011, Raster, 25 m,
-Water Body, CORINE, 2018, Raster, 100 m,
-Road Network, Global Roads Open Access Data Set (gROADS), 2013, Vector,
-Railway Network, OpenStreetMap, 2019, Vector,
-Settlement Area, European Settlement Map, 2019, Raster, 10 m,
-Wetland, CORINE, 2018, Raster, 100 m,
-Green Area, Tree Cover Density (TCD), 2015, Raster, 20 m,
-Protected Area, General Directorate of Nature Conservation And National Parks, 2019, Vector,
-Airport, General Directorate of State Airports Authority, 2019, Vector,
-Mining Area, CORINE, 2018, Raster, 100 m
Couple stress effects in a thin film bonded to a half-space
No full textThis study investigates the contact mechanics of a thin film laying on an elastic substrate within the context of couple-stress elasticity. It aims to introduce the effects of material internal length scale, which has proven an effective way of modeling structures at micro to nano-scales, allowing to capture their size dependent behavior. Specifically, stress analysis for a thin film bonded to a couple stress elastic half-space is considered under plane strain loading conditions by assuming that both shear stress and couple tractions are exchanged between the thin film and the substrate. The problem is converted to a singular integral equation, which is solved by expanding the shear stress tractions as a Chebyshev series. The results show that the introduction of couple tractions decreases the shear stress tractions and the axial load in the thin film. When the characteristic length is sufficiently small, but still finite, the results for classical elastic behavior are approached
Indentation of a free beam resting on an elastic substrate with an internal lengthscale
No full textThe plane strain problem of a slender and weightless beam-plate loaded by a transversal point force in unilateral contact with a couple stress elastic foundation is investigated. The study aims to explore the consequences of the material internal lengthscale on the contact mechanics. In particular, compatibility between the beam and the foundation surface demands that both displacement and rotation match along the contact line. To this aim, couple tractions are exchanged besides the traditional contact pressure until separation between the beam and the foundation occurs. The problem is formulated making use of the Green's functions for a point force and a point couple acting atop of a couple stress elastic half-plane. A pair of coupled integral equations is thus derived, that governs the distribution of contact pressure and couple tractions, with one of them being immediately solved to provide an explicit relation between the two unknowns. In this sense, we retrieve the concept of a mechanically equivalent action, as it is the case of the Kirchhoff shear for plates. The remaining integral equation sets a cubic eigenvalue problem, whose linear term accounts for the microstructure. Its numerical solution is sought by expanding the equivalent contact pressure in series of Chebyshev polynomials vanishing at the contact region ends points, namely the lift-off points, and then applying a collocation strategy. The contact length, the distributions of contact pressure and couple tractions under the beam and the shearing force and bending moment along the beam are then obtained as a function of the material characteristic length. Results clearly indicate that accounting for the material internal lengthscale is mainly realized through exchange of the couple tractions, in the lack of which results much resemble those of the classical solution. Specifically, greater contact lengths and a stronger focusing effect about the loading point are encountered, which become very significant when the contact length approaches the internal lengthscale
Temperature-dependent absorption edge and photoconductivity of Tl2In2S3Se layered single crystals
No full textFracture Detection And Characterization
No full textThe effects of fractures on full waveform acoustic logs are studied on the basis of field
observations, available theoretical models, and a series of ultrasonic laboratory experiments. Results from diffusion models applicable to fine microfractures and finite difference models of isolated fractures are reviewed. Laboratory experiments are carried
out with fine microfractures around the borehole in a Lucite model, and isolated single
fractures in aluminum models. Cases of horizontal and inclined (45°) fractures are
studied as a function of fracture aperture and frequency of Stoneley waves. A vertical
fracture model is also studied. Results indicate that the effect of different fractures are manifested differently on P, S, pseudo-Rayleigh, and Stoneley waves. Micro-fractures
surrounding a borehole attenuate Stoneley waves most strongly. Vertical fractures attenuate Stoneley waves more strongly than other phases in the wave train. Horizontal
and inclined fractures have a greater effect on P and S waves than on Stoneley waves.Massachusetts Institute of Technology. Full Waveform Acoustic Logging Consortiu
Ultrasonic Laboratory Study of Full Waveform Acoustic Logs in Boreholes with Fractures
No full textA set of ultrasonic experiments was carried out to determine the effects of horizontal and vertical fractures on full waveform acoustic logs. Boreholes of 1 cm diameter were drilled in aluminum blocks. Measurements were made with horizontal fractures of 0.05 mm, 1.0 mm, 2.5 mm, and 4.5 mm width and a vertical fracture of 1.0 mm width. The horizontal
fractures of even the smallest thickness significantly attenuate the P, S, and pseudo-Rayleigh waves. The Stoneley waves are the least attenuated, and attenuation increases
with increasing fracture width. The vertical fracture attenuates Stoneley waves most
significantly. Both scattering and fluid flow playa role in attenuation. The results may
qualitatively be extended to inclined open fractures, where we expect strong attenuation
of P and S waves and moderate attenuation of Stoneley waves.Massachusetts Institute of Technology. Full Waveform Acoustic Logging Consortiu
Radiocarbon dating of archaeological and geographical samples and their evaluation
No full textVarious samples obtained from different places in Anatolia were dated using radiocarbon technique. The results of unknown aged archaeological samples were chronogically evaluated. The wood and charcoal samples taken from archaic mine galleries showed that development of mining dates back to 2000 B.C. in Anatolia, Shells found around Konya plain proved that this place was occupied by a lake and the dates suggest that the lake level attained its maximum 20.000 years ago, and it possibly dried 14.000 years ago,Différents échantillons obtenus de divers sites d'Anatolie ont été datés par la technique du radio- carbone. Les résultats concernant des échantillons archéologiques d'âge inconnu sont évalués chronologiquement. Des échantillons de bois et de charbon pris dans des galeries de mines antiques montrent que le développement de l'art des mines remonte vers 2000 B.C. en Anatolie. Des coquilles découvertes autour de la plaine de Konya prouvent que cette zone était occupée par un lac et les dates suggèrent que le niveau de ce lac atteignit son maximum il y a 20,000 ans, et il s'assécha peut-être il y a 14.000 ans.Ergin M., Kis M., Guler R. Radiocarbon dating of archaeological and geographical samples and their evaluation. In: Revue d'Archéométrie, n°4, 1980. pp. 73-76
Single and binary biosorption of Cu(II), Ni(II) and methylene blue by raw and pretreated Spirogyra sp.: Equilibrium and kinetic modeling
No full textThe raw and pretreated Spirogyra sp. were used for the single and binary removal of Cu(II), Ni(II) and methylene blue (MB) from aqueous solution. The effects of pH, contact time, initial pollutant concentration, biosorbent dosage and ionic strength (NaCl) on removal efficiency were investigated. The biosorption capacity of Cu(II), Ni(II) and MB onto raw and pretreated Spirogyra sp. was found as the following order: MB > Cu > Ni and Ni > MB > Cu. The pseudo-first order, pseudo-second order and the intraparticle diffusion models were applied to the experimental data. The thermodynamic parameters (?H, ?S, ?G) were calculated. Desorption studies was also done. The structural characteristics of biosorbent were determined through FT-IR spectrums and SEM images. Also, binary biosorption studies showed that removal efficiency of dominant pollutant reduced by the presence of the other ion in aqueous solution. © 2013 Elsevier Ltd. All rights reserved.M-326This work is supported by the Scientific Research Project Fund of Cumhuriyet University under the project number M-326.Guler, U.A.; Department of Environmental Engineering, Engineering Faculty, Cumhuriyet University, Sivas 58140, Turkey; email: [email protected]
Neutron Background Predictions and Measurement at ATF2 Beamline
No full textAbstractIn electron machines, neutrons near the interaction region are dominantly produced by photonuclear processes in electromagnetic showers initiated by lost particles in dense materials. The photonuclear cross-section and the high multiplicity of low-energy photons make the low-energy regime vastly dominating this neutron production. ATF2, operating at 1.3GeV, offers most of the phase space to assess the widely used Geant4 toolkit with this respect. The experiment beam dump is used to mimic the above mentioned high density region: the flux of neutron is initiated by the electron beam showering in the dump; which then scatters up to exiting the dump. The measurement of the time dependent flux is sensitive to both the neutron production and transport. Measurements of neutron fluxes performed with plastic and CsI scintillators will presented. They will be compared to a Geant4 simulation of the setup. The simulation makes use of biasing techniques to boost the simulated flux exiting the beam dump which results will be discussed
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