Search

The attenuation factor or quality factor (Q-factor or Q) has been used to measure the energy attenuation of seismic waves propagating in underground media. Many methods are used to estimate the Q-factor. We propose a method to calculate the Q-factor based on the prestack Q-factor inversion and the generalized S-transform. The proposed method specifies a standard primary wavelet and calculates the cumulative Q-factors; then, it finds the interlaminar Q-factors using the relation between Q and offset (QVO) and the Dix formula. The proposed method is alternative to methods that calculate interlaminar Q-factors after horizon picking. Because the frequency spectrum of each horizon can be extracted continuously on a 2D time-frequency spectrum, the method is called the continuous spectral ratio slope (CSRS) method. Compared with the other Q-inversion methods, the method offers nearly effortless computations and stability, and has mathematical and physical significance. We use numerical modeling to verify the feasibility of the method and apply it to real data from an oilfield in Ahdeb, Iraq. The results suggest that the resolution and spatial stability of the Q-profile are optimal and contain abundant interlaminar information that is extremely helpful in making lithology and fluid predictions. [ABSTRACT FROM AUTHOR]

We develop an alkaline electroless bath for deposition of a conformal Pt layer 40 nm thick on titania nanotubes 800 nm long. The charge storage capacity (CSC) and electrochemically active surface area (ECSA) of this Pt-coated titania nanotube array have been studied to evaluate its potential as a bio-electrode for implantable bio-electronic devices. Images from electron microscopes confirm the formation of a uniform Pt film on both the internal and external surfaces of the nanotubes. The X-ray diffraction pattern indicates a preferred (111) orientation. Analysis from X-ray absorption spectroscopy on the plating bath suggests a reduction sequence of Pt 4+  → Pt 2+  → Pt. The Pt-coated titania nanotube array has large CSC and ECSA values, attributed to the hollow tubular nanostructure with a conformal Pt coating. [ABSTRACT FROM AUTHOR]

Cold supply chain distribution systems ensure the freshness of temperature-sensitive products during transportation. In this study, we investigated a fresh food company's cold supply chain distribution. Making fresh food available and achieving quality and safety, requires proper planning of vehicle routing, we addressed a routing problem that simultaneously considers time windows, multiple trips per vehicle, a heterogeneous fleet, parking constraints, unloading time at customer position, and limited duration, minimizing related operational costs. We formulate this problem as a mixed-integer programming model. Since this problem is NP-hard, we also propose a genetic algorithm with two adaptive-parameter mechanisms to solve it within a reasonable computational time. Extensive experiments were conducted to assess the performance of different approaches in a real-world application. The results demonstrate that the algorithms are robust and efficient. The proposed algorithms can reduce operational costs by more than 20% compared to the current practical planning approach. [ABSTRACT FROM AUTHOR]