Technetium—aspirin molecule complexes

Technetium-aspirin and technetium-aspirin-like molecule complexes were prepared. The structure of N-acetylanthranilic acid (NAA) has been decided through CNDO calculations. The ionization potential and electron affinity of the NAA molecule as well as the charge densities were calculated. Comparative studies of the electronic absorption spectra of acetylthiosalicylic acid (ATS) and aspirin (Asp) reveal the structure resemblance in which the acetyl carbonyl group is perpendicular to the plane of the corresponding organic acid. The studies of the electronic absorption spectra of NAA and anthranilic acid reveal the planarity of the NAA molecule. The electronic absorption spectra of Tc(V)-Asp and Tc(V)-ATS complexes have two characteristic absorption bands at 450 and 600 nm, but the Tc(V)-NAA spectrum has one characteristic band at 450 nm. As a comparative study, Mo-ATS complex was prepared and its electronic absorption spectrum is comparable with the Tc-ATS complex spectrum.     

Building cost effective lower layer VPNs: The ILEC/CLEC dilemma

Layer 2 and layer 1 Virtual Private Network (VPN) services; ranging from simple leased lines to extending private LANs across public networks, are commonplace today. With the continuously growing economic difficulties, capital meltdown, and telecommunication business turmoil, delivering those VPN services at the lowest cost or with the maximum revenue margin, while committing to Service Level Agreements (SLA), has become essential. We show that whether we tackle the optimal VPN design problem from an Incumbent Local Exchange Carrier (ILEC) standpoint or from a Competitive Local Exchange Carrier (CLEC) standpoint, we obtain contradictory rules. We show that by building Edge Disjoint VPN trees and spreading the traffic all over the network, the ILEC can achieve maximum throughput and enhanced network performance; while by concentrating all the VPN traffic over a single tree, the CLEC can minimize the cost of leased bandwidth. We then propose two simple algorithms that can help carriers and service providers leverage their networks and increase their revenue margins while meeting SLA requirements. Copyright © 2010 John Wiley & Sons, Ltd.     

ANFIS modeling of CO2 separation from natural gas using hollow fiber polymeric membrane

The present study is proposed to develop the Adaptive Neuro-Fuzzy Inference System optimized by genetic algorithm to estimate CO₂ value in permeate stream using a hollow fiber polymeric membrane for separation of binary gas containing CO₂ and CH₄ in natural gas. To that end, a number of 65 samples was gathered from the literature. Results indicated that the proposed ANFIS model has great potential with high correlation (R² = 0.9993) and less error (RMSE = 0.0064) for estimation of aforementioned parameter.     

Comprehensive partial decoding approach for two-level relay networks

Partial decoding scheme is a scheme in which each relay decodes only part of the transmitted message. Obviously, the achievable rates proposed by the partial decoding scheme subsume the achievable rates proposed by the full decoding scheme. The other motivation of using partial decoding scheme is that there are some special classes of relay networks such as semi-deterministic and orthogonal relay networks such that their capacities are obtained via this scheme. The authors propose a comprehensive partial decoding scheme based on regular encoding/sliding window decoding analysis to propose a new achievable rate for two-level relay networks. In contrast with the previously proposed methods, here the authors consider all possible partial decoding states that can occur between the different parts of the messages of the source and the relays in a two-level relay network. In this way, the common and private parts of the message transmitted by the source are defined to be decoded by the appropriate relays. Moreover, in the proof, the authors take advantage of regular encoding/sliding window decoding scheme that has superiorities to regular encoding/backward decoding and irregular encoding/random partitioning, in having less delay and yielding higher rates, respectively.     

Automatic image segmentation by integrating color-edge extractionand seeded region growing

We propose a new automatic image segmentation method. Color edges in an image are first obtained automatically by combining an improved isotropic edge detector and a fast entropic thresholding technique. After the obtained color edges have provided the major geometric structures in an image, the centroids between these adjacent edge regions are taken as the initial seeds for seeded region growing (SRG). These seeds are then replaced by the centroids of the generated homogeneous image regions by incorporating the required additional pixels step by step. Moreover, the results of color-edge extraction and SRG are integrated to provide homogeneous image regions with accurate and closed boundaries. We also discuss the application of our image segmentation method to automatic face detection. Furthermore, semantic human objects are generated by a seeded region aggregation procedure which takes the detected faces as object seeds.     

An investigation of different gas injection scenarios as enhanced condensate recovery method in a naturally fractured gas-condensate reservoir

In gas condensate reservoirs, when the bottom hole pressure falls below the dew point pressure condensates are formed. This causes hydrocarbon liquid saturation around the well bore region. This phenomenon is called condensate blockage or condensate banking. Condensate recovery reduction due to condensate banking near the well bore region is an important problem in gas condensate reservoirs. The common method to prevent the condensate banking is gas cycling (reinjection of produced dry gas) into the reservoir that can contribute to the condensate vaporization, thus increasing the condensate recovery factor. The objective of this study was to find a suitable replacement for gas cycling. For this purpose, an investigation on the effects of injection of different types of gases (CO₂, N₂, and C₁) on enhance condensate recovery factor and pressure maintenance were performed. This research was done on one of the Iranian gas condensate reservoirs through a compositional simulator. The two-parameter Peng-Robinson equation of state (EOS) and Lohrenz-Bray-Clark correlation were used to model reservoir fluid properties through regression on the pressure-volume-temperature (PVT) experimental data. A fracture network was distributed over the reservoir, so a dual porosity/dual permeability model was selected for better evaluation of the fracture system. Then, various scenarios of natural depletion and CO₂, N₂, C₁, and gas cycling injection were studied. The results showed that CO₂ injection scenario being associated with the highest efficiency compared to that of other gases.     

Comparison of the physicochemical properties and mineralogy of Chinese (Beihai) and Brazilian kaolin

Beihai area (China) has about 500 million tons kaolin reserves with potential applications in ceramics, paint, plastic and rubber-filler industries, but unlike the Brazilian kaolin, it is not good in paper-coating industry. In order to understand the differences between Chinese (Beihai) and Brazilian kaolin, their individual physicochemical properties, morphologies, crystal structures, and surface characteristics were systematically investigated and compared. The results showed that the viscosity concentration, specific surface area and zeta potential of Brazilian kaolin were higher than those of Beihai kaolin. SEM and TEM images revealed that Brazilian kaolin had more regular particle shape, smoother surface and larger diameter–thickness ratio than those of Beihai kaolin. Moreover, XRD and TG/DSC analyses exhibited that Beihai kaolin was low ordered kaolinite with lower value of Hinckley index, average flake thickness along c-axis and endothermic peak temperature as compared to Brazilian kaolin. Furthermore, the crystal structures refined by the Rietveld method of Beihai kaolin showed a greater distortion of [SiO₄] tetrahedron than that of Brazilian kaolin. It can be concluded that low viscosity concentration, low degree of order, and irregular particle shape of Chinese (Beihai) kaolin are the reasons why it is not suitable for use in the paper-coating industry.     

An image steganography method based on integer wavelet transform

This paper presents a novel approach for Image steganography based on Integer Wavelet Transform. In this method, the cover image is mapped to a specific frequency domain. Then in the obtained frequency domain, edge coefficients are classified based on their MSBs. The suggested method prevents changes in MSB in a way that receiver can extract the information without any mistakes. Considering the preformed classification, secret bits will be embedded in the frequency coefficients and then with the use of inverse transformation, stego image will be obtained. The most important features that our work obtained are good adaptation with human vision system and retrieval of data without error. Simulation results show that our proposed method has a good adaptation with human vision system (HVS) and outperforms in terms of PSPNR factors over recently published works.     

Use of artificial neural networks for estimation of agricultural wheel traction force in soil bin

This paper presents an application of artificial neural networks (ANNs) for the prediction of traction force using readily available datasets experimentally obtained from a soil bin utilizing single-wheel tester. Aiming this, firstly the tests were carried out using two soil textures and two tire types as affected by velocity, slippage, tire inflation pressure, and wheel load. On this basis, the potential of neural modeling was assessed with multilayered perceptron networks using various training algorithms among which, backpropagation algorithm was compared to backpropagation with declining learning rate factor algorithm due to their primarily yielded superior performance. The results divulged that the latter one could better achieve the aim of study in terms of performance criteria. Furthermore, it was inferred that ANNs could reliably provide a promising tool for prediction of traction force and its modeling.