A robust CELP coder with source-dependent channel coding

A CELP coder using Source Dependent Channel Encoding (SDCE) for optimal channel error protection is introduced. With SDCE, each of the CELP parameters are encoded by minimizing a perceptually meaningful error criterion under prevalent channel conditions. Unlike conventional channel coding schemes, SDCE allows for optimal balance between error detection and correction. The experimental results show that the CELP system is robust under various channel bit error rates and displays a graceful degradation in SSNR as the channel error rate increases. This is a desirable property to have in a coder since the exact channel conditions cannot usually be specified a priori

Effect of Body Composition on Ventilation Parameters in a Group of Young Sudanese Females

Background: Lung Function Test helps (LFT) in the diagnosis and follow up of patients with pulmonary or cardiac diseases. Ignoring BMI and body composition during interpretation of LFT results may lead to wrong diagnosis and unnecessary use of drugs.Objective: This study was conducted to test the hypothesis that differences in body composition between individuals can explain some of the features of LFT that are explained by variations in age, sex, and height only.Methods: This observational analytical cross sectional study which included 150 young adult females. Those with history of amenorrhea, smoking, asthma or cardiac disease were excluded. Anthropometric measurements including: BMI, waist circumference (WC) and body fat percent calculated from skinfold thickness measurements were done. Dynamic spirometric tests were performed using digital spirometer; FEV1, FVC, FEV1% were measured.Results: Both obese and underweight subjects had a significant reduction in FEV1 (P=.002) and FVC (P=.004) compared to normal ones. FEV1% was significantly higher in the overweight and obese group compared to the other two groups (P=.02). Body weight, BMI, and WC had significant positive correlation with FEV1 and FEV1% in young healthy females.Conclusion: Increase in BMI, body weight, WC and body fat showed positive significant correlation with FEV1% and may give a restrictive pattern in LFT. Underweight subjects may show significant reduction in lung function if their BMI is not considered

Characterization of Nanosilica and Comparing Its Effect on Crude Oils and Diesel Fuel

Heavy oils generally exhibit high viscosity, which is detrimental to their production, transport, and refining. The Oil & Gas industry has thoroughly investigated the use of chemical agents to improve the mobility of this type of low-quality crude oils at the surface as well as reservoir conditions for many years. In this sense the main objective of this work is to investigate the viscosity reduction of heavy oil resulting from the presence of silica nanoparticles by asphaltene adsorption process. Silica nanoparticles was produced successfully in this work from sand of Mount Sannam in Basra city (south of Iraq) by chemical and physical methods (SiO2ch and SiO2ph respectively). The XRD results indicated a high purity SiO2ch NPs was produced with purity of 96.8%, while, the purity of SiO2ph NPs was about 87.2%. The main particle size analyzer (PSA) were measured to be 35 nm and 22 nm for SiO2ch and SiO2ph respectively. On the other hand, the BET total surface area of SiO2ch and SiO2ph NPs were 520 m2/g and 705 m2/g respectively. Also, the SEM results showed a uniform distribution of nanoparticles for both prepared silica nanoparticles. The FTIR results indicated a high intensity bonds were formed due to present of functional groups of Si-O-Si, O-Si-O and Si-O. Two Iraqi crude oil samples was selected to be as base fluid with APIs (17.4 and 29.1). Also, diesel fuel with API= 40.91 was tested. For each hydrocarbon a nanofluid was prepared by adding silica nanoparticles to parent fluid. Four concentration of silica nanoparticles were added to the parent fluid (250, 500, 1000 and 1250 mg/L). And also, used a bath ultrasonic method for dispersing NPs inside the parent oils. Keywords: Petroleum Pipelines; natural nanoparticles; viscosity reduction; silica preparation; silica characterization; asphaltene adsorption; crude oil DOI: 10.7176/JNSR/9-4-0

Hydrodynamics, Mass and Heat Transferin Reactive Distillation

The ethyl acetate synthesis via heterogeneous reactive distillation is studied experimentally using ethanol and acetic acid. Three types of cation exchanging resins were used as catalysts: Zerolit 225, Zerolit 226 and Ambylite 400. Experiments were carried out in two units of the same dimensions. Each unit consisted of three sections: rectifying, reactive and stripping sections of heights (60+25+20) cm respectively and 2.5cm column diameter. The first unit (column-A-) was a fractionation type and the second unit (column-B-) was packed column. The packing type was hollow glass cylinders with 10 mm height, and 4, 5 mm inner and outer diameter respectively. <br /> The experiments were carried out by using two operation modes. The semi-batch and continuous operation mode. In the first part of present investigation, the semi-batch mode was used to evaluate the catalyst type and to evaluate the performance of reactive distillation unit configuration (Fractionation and packed column). Results show that, the column-B- gave higher conversion rates than column-A-. This is attributed to the high surface area available for liquid vapour contact in packed type column, which leads to increasing mass transfer rates. On the other hand, Ambylite 400 catalyst showed higher activity for esterification reaction than other two types of catalysts. <br /> The second part of work continued with column -B- only. It is well known that, the esterification process is regarded one of exothermic reactions. Therefore, the monitoring of the temperature distribution along column axial for all three types of catalysts showed that the temperature distribution was essentially the same due to steady state operation in continuous operation mode. On the other hand, the effect of reflux ratio on temperature distribution was clearly noted, that is as the reflux ratio increased the temperature distribution along the column was reduced for each type of catalysts.<br /> On the other hand, the experimental results point that, as a reflux ratio increases the conversion rates of acetic acid is increased too because such increasing is related to high mass transfer rates between vapour and liquid along reactive distillation column. <br /

Improve the Process of Enhancing Oil Recovery (EOR) by Applying Nanomagnetic Cobalt Ferrite Nanoparticles

In this paper we reported nano-crystalline cobalt ferrite powders were synthesized using co-precipitation method at 600 °C, 700 °C and 800 °C. The structural, morphological and magnetic properties of the powders were investigated by x-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). Infrared spectral analysis data between 200 and 1000 cm-1 defined the intrinsic cation vibrations of the characteristic spinel structure system. The saturation magnetization (Ms) and coercivity (Hc) of the CoFe2O4 were found to be in the range of 94-33 emu/g, which is still in the range of hard ferrite. The observed variation in saturation magnetization, coercivity and remanence magnetization as a function of increasing the temperature and grain size of samples. From this point of view, nano-scale size of nanoparticles makes them efficient for using in borehole stability maintaining for enhancing oil and gas recovery efficiency improvement. The large value of magnetic pressure (-2.95699) are expected to be useful in oil recovery applications. It has also been found that the choice of nanoparticles for application in oil recovery depends on nature, magnetic and electric properties of the reservoir rock

Investigation and Simulation of Catalytic Reforming Reactions of Iraqi Heavy Naphtha Using Pt-Sn/Al2O3 and Pt-Ir/Al2O3 Catalysts

In the present work experimental and simulation studies have been carried out to describe the reaction kinetics of catalytic reforming process using Iraqi heavy naphtha as a feedstock. Two types of bi-metals catalysts were prepared (Pt- Sn/Al2O3 and Pt-Ir/Al2O3) supported on γ-Al2O3. The main three described reforming reactions were investigated (dehydrogenation, dehydrocyclization, and hydrocracking) to characterize catalysts performance in term of activity and selectivity. The performances of catalysts were investigated under the following operating conditions: reaction temperature range of 480-510 ˚C, weight hour space velocity range of 1-2 hr-1, pressure at 6 atm, and hydrogen to hydrocarbon ratio of 4:1. The results showed that the higher conversion of Iraqi heavy naphtha components (i.e., paraffins and naphthenes) increased with temperature whereas, weight hourly space velocity has shown inverse impact on conversion. On the other hand, it was concluded that the yields of aromatics and high components are increased for both types of catalysts (Pt-Sn/Al2O3 and Pt-Ir/Al2O3) under the same operating conditions. A comprehensive mathematical model and simulation was developed in the present work to describe the reaction kinetics of reforming reactions. The comparison between the concentration of (paraffin’s, naphthenes, and aromatics), and temperature profile of experimental and simulation results showed a good agreement and the deviation confined between them in the range of 1.93% to 14.51%

Experimental Study and Simulation of Iraqi Heavy Naphtha Catalytic Reforming Reactions Using Pt-Ir-Sn/AL2O3 and Pt-Ir/AL2O3 Catalysts

In present study experimental and mathematical model have been carried out to describe the reaction kinetics of catalytic reforming process using Iraqi heavy naphtha as a feedstock for the process. Two types of catalysts were prepared (Pt-Ir-Sn/AL2O3 and Pt-Ir/AL2O3) supported on γ-AL2O3. The main three described reforming reactions were investigated (dehydrogenation, hydrocracking, and dehydrocyclization) to characterize catalysts performance in term of activity and selectivity. The performance of catalysts were investigated under the following operating condition: reaction temperature range of 480-510 ˚C, weight hour space velocity range of 1-2hr-1, pressure at 6 atm, and hydrogen to hydrocarbon ratio of 4:1.The results show higher conversion of Iraqi heavy naphtha components (i.e., Paraffins and Naphthenes) with higher temperatures whereas; weight hourly space velocity has shown negative impact on conversion (i.e., higher WHSV shows lower conversion). In general, it was noted that the yields of aromatics and light components are increased for both types of catalysts (Pt-Ir-Sn/AL2O3 and Pt-Ir/AL2O3) under the same operating conditions. Results of tri-metal catalyst better than bi-metal catalyst. A comprehensive mathematical model and simulation was developed in the present work to describe the reaction kinetics of reforming reactions. The model predicts the concentration, conversion, and temperature profile with time and axial direction of the reactor. The comparison between experimental and simulation results of the concentrations of (Paraffin’s, Naphthenes, and Aromatics), and temperature showed a good agreement with a deviation confined 19.50%

Investigation Nano coating for Corrosion Protection of Petroleum Pipeline Steel Type A106 Grade B; Theoretical and Practical Study in Iraqi Petroleum Sector

In the present investigation, titania (TiO2) nano-thin films were deposited on steel type A106-B, by using the Pulse Laser Deposition (PLD) technique to obtain passive layers of nano-coating. Electrochemical methods (Tafel completion) are used for study corrosion behavior of steel coating. The A106-B specimens were evaluated in 3.5 wt. % NaCl aqueous solution by using polarization technique with pH adjustment to 4.0 in order to determine the corrosion rate. The samples of TiO2 thin films were characterized by SEM, AFM, XRD, and FTIR. The input parameters were substrate temperature (100, 200 and 300) ’0C’, number of pulse (300, 400 and 500) and fluencies energy (800, 900 and 1000) mJ/cm2, have been investigated to detect their impact on corrosion reduction rate using Taguchi methodology orthogonal array and Analysis of Variance (ANOVA).The ANOVA results indicates that number of shoots pulse significantly affecting the corrosion rate in PLD technique, which is highest among the contributions of the other parameters which is (58.03%) about three times of the fluencies energy (19.12%).The results show that the TiO2 deposition on steels offers an excellent corrosion resistance about 99 times as compared with uncoated steel. The optimum conditions to minimum values corrosion rate are: temperature of 300ºC, number of laser pulses at 300, and fluencies energy equal to 1000 mJ/cm2. Finally the optimal parameters that was used to predict the conclusions were (98.6) to the response of corrosion rate

Reaction Kinetics of Acetic Acid and n-Butanol Esterification Catalyzed by Dowex 50 Catalyst

The reaction kinetics of the n-butanol esterification and acetic acid on acidic solid catalyst named Dowex 50 under atmospheric pressure was investagated in this work. Reaction experiments were carried out in a stirred batch reactor at temperature range of 343 to 363 K, under various catalyst loads and various starting reactants feed ratios. The experimental data were fitted to estimate the kinetic parameters for reaction mechanisms by using MATLAB 7 software. The chemical equilibrium composition was measured and kinetic information was obtained at the same temperature range. The results show that the activation energy of n-butanol esterification reaction was found to be 39.975 kJ/mol. Finally the results of produced reaction mechanisms were compared with experimental results to validate the reaction mechanism. Then it was conclud that the model results with the regressed kinetic parameters are in excellent agreement with the experimental results

A Self-Learning MAC Protocol for Energy Harvesting and Spectrum Access in Cognitive Radio Sensor Networks

The fusion of Wireless Sensor Networks (WSNs) and Cognitive Radio Networks (CRNs) into Cognitive Radio Sensor Networks (CRSNs) is quite an attractive proposal, because it allows a distributed set of low-powered sensor nodes to opportunistically access spectrum bands that are underutilized by their licensed owners (called primary users (PUs)). In addition, when the PUs are actively transmitting in their own bands, sensor nodes can switch to energy harvesting mode to obtain their energy needs (for free), to achieve almost perpetual life. In this work, we present a novel and fully distributed MAC protocol, called S-LEARN, that allows sensor nodes in a CRSN to entwine their RF energy harvesting and data transmission activities, while intelligently addressing the issue of disproportionate difference between the high power necessary for the node to transmit data packets and the small amount of power it can harvest wirelessly from the environment. The presented MAC protocol can improve both the network throughput and total harvested energy, while being robust to changes in the network configuration. Moreover, S-LEARN can keep the cost of the system low, and it avoids the pitfalls from which centralized systems suffer