Inter-cell interference in multi-tier heterogeneous cellular networks: modeling and constraints

Telecommunication Systems - Interference is the main source of capacity limitation in wireless networks. In some medium access technologies in cellular networks, such as OFDMA, the allocation of...     

Interpretation of Cyclic Potentiodynamic Polarization Test Results for Study of Corrosion Behavior of Metals: A Review

Protection of Metals and Physical Chemistry of Surfaces - The cyclic potentiodynamic polarization technique is a method for evaluating the susceptibility of a metal to localized corrosion such as...     

Simultaneous kinetic spectrophotometric determination of sulfide and sulfite ions by using an optode and the partial least squares (PLS) regression

The characterization of an optical sensor membrane is described for simultaneous determination of sulfite and sulfide ions based on the immobilization of crystal violet on a triacetylcellulose membrane. The absorbance of the membranes decreased by increasing sulfite and sulfide concentration. The partial least squares (PLS-1) calibration model based on spectrophotometric measurement for simultaneous determination of sulfite and sulfide ions was applied. This method is based on the difference between the rate of the reaction of sulfide and sulfite with membranes in pH 7.0 buffer solution and at 25 °C. The experimental calibration matrix for partial least squares (PLS-1) calibration was designed with 18 samples. The cross-validation method was used for selecting the number of factors. The results showed that simultaneous determination could be performed in the range of 200–2000 μg mL⁻¹ (2.5–25 mmol L⁻¹) and 80–900 μg mL⁻¹ (2.5–28.125 mmol L⁻¹) for sulfite and sulfide, respectively. The sensor can readily be regenerated with water and the color is fully reversible. The sensor was successfully applied to the simultaneous determination of sulfide and sulfite in water samples.     

Investigation of calcareous deposits formation on copper and 316L stainless steel under cathodic polarization in artificial seawater

The formation and growth of calcareous deposits on 316L stainless steel and copper under cathodic polarization in artificial seawater were investigated by electrochemical tests and analytical techniques such as SEM, EDX and XRD. The deposits mineral compositions were related to the types of metallic materials and were different on each substrate. On 316L stainless steel at potentials less negative than the water reduction potential (−1100 mV/SCE), the deposits were composed of aragonite with low amounts of brucite; at the potentials more negative than the water reduction potentials, only of brucite. Around the water reduction potentials, the deposits were composed of both aragonite and brucite together. However the formation of brucite was noted before activating the water reduction processes. The results were moderately similar to that on mild steel and the type of deposited phases depended on potentials, at which the cathodic protection was carried out. The deposits formed on copper differed from those on 316L stainless steel and the types of deposited phases were independent from water reduction potential on copper (−1150 mV/SCE). Hence, the deposits were composed only of aragonite at all potential ranges. Due to the low current densities observed in chronoamperometric curves during cathodic polarization and in sufficient alkalinity, it seemed that the brucite could not deposit on this metallic substrate. The article is published in the original.     

Cold atmospheric-pressure plasma treatment of turmeric powder: microbial load,essential oil profile,bioactivity and microstructure analyses

Turmeric powder treated by cold atmospheric-pressure plasma (CAPP) at 25 kV for various times of 3, 5 and 7 min was examined for microbial load, essential oil profile, colour parameters, total phenolic content, total flavonoid content, antioxidant activity and microstructure. CAPP treatment caused a reduction of approximately 1.5 log CFU g⁻¹ in aerobic viable cell count of turmeric powder, which was most pronounced during the first 3 min of the treatment. The inactivation kinetic was fitted to the Weibull model with R² of 0.9913 and RMSE of 0.0641. Gas chromatography–mass spectrometry analysis of essential oils identified twelve different components for turmeric powder of which 1,8-Cineole, α-Terpinolene and trans-Caryophyllene were lost and ar-Turmerone and α-Zingiberene experienced considerable increases after plasma treatment. The double-edged effect of plasma treatment was also observed on bioactivity. Scanning electron microscopy showed formation of super-agglomerates in plasma-treated samples due probably to coalescence of the granules with plasma-damaged walls.     

Synchronization in multi-echelon supply chain applying timing discount

Due to the increasing emphasis on the effective management of the supply chain, synchronization and cooperation issues between suppliers and retailers in decentralized multi-echelon inventory/distribution systems have gained much attention in the recent years. In this paper, we consider coordination issues of a distribution system composed of a manufacturer, a supplier (distributor), and several retailers. The supplier outsourcing a third party offers a timing discount to multiple retailers in order to synchronize the timing of their orders with the order cycle. It is also assumed that retailers are allowed to face stock outs. In this paper, a mathematical model is developed to analyze the problem. Results show that while synchronizing the supplier and the outsourcer enhances the supply chain efficiency, offering any type of timing discount by the supplier decreases the supply chain efficiency. It is also noted that having coordination between the manufacturer and the supplier has no impact on the supplier’s profit but may decrease the retailer’s costs. It is believed that our findings provide potential and significant managerial implications in the area of supply chain coordination when these systems are decentralized.     

Experimental and theoretical study of phase behavior for live oil during CO2 EOR process

Carbon dioxide flooding is a very complicated process, involving phase behavior that could increase oil recovery by means of swelling, evaporating, and lowering oil viscosity. The present investigation reports the results of extensive experimental and theoretical work to determine the viscosity and swelling factor changes of the live oil in the Cheshmeh Khoshk reservoir in southern part of Iran (Ilam District), and also minimum miscible pressure is determined. In this study, we want to study the potential of carbon dioxide injection application in improving oil recovery by simulating a slim-tube experiment. In order to get representative fluid samples of a reservoir, it was necessary that the right operation of mixing the separator oil and gas samples to match the bubble point pressure be carried out. The potential application of the study is that we could have a good estimate of the recovery improvement under carbon dioxide gas injection, which will be the basic input parameter for the economic feasibility study, and also a decision can then be made whether to implement or abandon the prospective project.     

Influence of commercial culture composition and cow milk to soy milk ratio on the biochemical,microbiological, and sensory characteristics of a probiotic fermented composite drink

Food Science and Biotechnology - In this study, the effects of various ratios of cow milk to soy milk (100:0, 75:25, 50:50, 25:75, and 0:100) and three types of commercial culture composition...