The Effect of Ductile-Lithic Sand Grains,Overpressure and Secondary Dissolution on Porosity and Permeability and Their Relevance to Hydrocarbon Exploration in Aşkale Sub-Basin,East Anatolia,Turkey

Ductile lithic grain, secondary porosity, temperature, and overpressure control porosity and permeability in the Mio-Pliocene and Upper Oligocene sandstones of the A?kale sub-basin in East Anatolia. Ductile lithic grains account for between approximately 60–90% of the original sand grain population. There is a pronounced loss of porosity with increasing bruial depth in this sub-basin. At depths of less than 3000 m, this is due solely to ductile-lithic grain compaction where the rate of porosity loss of with depth increases with increasing ductile-lithic grain content. But at depths greater than 3000 m, the steep porosity increases with depth due to secondary solution activities and overpressure in the A?kale sub-basin in East Anatolia. Secondary porosity is a common diagenetic feature in the more deeply buried (> 3000 m) sediments in the A?kale sub-basin. The secondary porosity arises principally from dissolution of feldspar, to a lesser extent, of the quartz (approximately 10–30%). Overpressure is due to tectonic stress. Reservoir quality is thus controlled by secondary solution activities, overpressure, temperature (geothermal gradient) and depth of burial in the A?kale sub-basin in East Anatolia Basin.     

Optical characterization of curved organic light emitting diodes with different thicknesses of barrier layers and cylindrical radii of curvatures

Organic light emitting diode (OLED) light sources were bent to study theoretically and experimentally the effect of bending on the optical characteristics. First, the effect of superstrate thickness on the emitted light was theoretically studied for cylindrical and spherical bent OLEDs, and the transmission and the reflection coefficients were simulated. In the second step, four OLEDs were fabricated; three of them with polyethylene naphthalate (PEN) superstrates and one with glass superstrate for comparison. In the third step, three jigs were fabricated with radii of R₀ = ∞ mm (plane), R₂ = 143 mm (cylinder), and R₅ = 56.7 mm (cylinder). The OLEDs were fixed on the jigs and the on-axis and off-axis spectra of each were measured. In addition, the effect of barrier thickness on the optical characteristics was studied by changing the thickness from 100 to 150 nm. The reduction in bent radius resulted in shifts of the spectra toward the shorter wavelengths, and meanwhile, the width of the spectra was reduced. Similar result was found when the barrier layer was increased; that is, the peaks of the shorter spectra increased resulting in narrow bandwidth spectra. By bending a flexible OLED, a color change acquires and it increases with the bending radius, as well as by the increase of the barrier layer thickness.