Simulation and energy optimization of the stabilizer tower of a pyrolysis gasoline hydrogenation unit

Energy optimization of second distillation tower of a pyrolysis gasoline hydrogenation unit has been studied by the thermal cycle of vapor recompression method. The mentioned cycle is connected to the second distillation tower of the stabilizer of pyrolysis gasoline, and the results are found promising. The composite pinch curve for both the current and the optimized methods are shown. Moreover, an increase in the heat transfer rate in heat exchanger E-1014 causes energy recovery in reboiler. According to simulation results, by vapor recompression to 1970 kPa and using this heat source for thermal integration, condenser and reboiler’s energies are decreased by 56.93 and 30.4 percentage, respectively.     

Modeling,design, and optimization of a cost‐effective and reliable hybrid renewable energy system integrated with desalination using the division algorithm

People in the Middle East are facing the problem of freshwater shortages. This problem is more intense for a remote region, which has no access to the power grid. The use of seawater desalination technology integrated with the generated energy unit by renewable energy sources could help overcome this problem. In this study, we refer a seawater reverse osmosis desalination (SWROD) plant with a capacity of 1.5 m³/h used on Larak Island, Iran. Moreover, for producing fresh water and meet the load demand of the SWROD plant, three different stand‐alone hybrid renewable energy systems (SAHRES), namely wind turbine (WT)/photovoltaic (PV)/battery bank storage (BBS), PV/BBS, and WT/BBS are modeled and investigated. The optimization problem was coded in MATLAB software. Furthermore, the optimized results were obtained by the division algorithm (DA). The DA has been developed to solve the sizing problem of three SAHRES configurations by considering the object function's constraints. These results show that this improved algorithm has been simpler, more precise, faster, and more flexible than a genetic algorithm (GA) in solving problems. Moreover, the minimum total life cycle cost (TLCC = 243 763$), with minimum loss of power supply probability (LPSP = 0%) and maximum reliability, was related to the WT/PV/BBS configuration. WT/PV/BBS is also the best configuration to use less battery as a backup unit (69 units). The batteries in this configuration have a longer life cycle (maximum average of annual battery charge level) than two other configurations (93.86%). Moreover, the optimized results have shown that utilizing the configuration of WT/PV/BBS could lead to attaining a cost‐effective and green (without environmental pollution) SAHRES, with high reliability for remote areas, with appropriate potential of wind and solar irradiance.     

Synthesizing the note-specific atoms based on their fundamental frequency,used for single-channel musical source separation

The musical source separation deals with extracting the musical signals from a mixture. To attain this goal, one of the efficient methods is to decompose the mixture into a dictionary of some basic functions that inherently describe the instruments. Usually, a unique function is synthesized for each of the notes of each instrument, called the note-specific atom. In this paper, a sine-harmonic model is utilized to synthesize note-specific atoms and the note’s fundamental frequency is used as a prior information to determine the model parameters. To calculate these parameters, the training signal spectrum is processed only around the main note harmonics. Experimental results demonstrated that the proposed method is much faster in note-specific atoms synthesis, without decreasing the source separation quality and can also eliminate the single-frequency noise from training signals.

     

Preparation and characterization of a novel gelatin–poly(vinyl alcohol) hydrogel film loaded with Zataria multiflora essential oil for antibacterial–antioxidant wound‐dressing applications

This study was performed to evaluate the properties of poly(vinyl alcohol) (PVA), gelatin, and PVA–gelatin dispersions and films enriched with Zataria multiflora essential oil (ZO). The results reveal that the ζ potential, particle size, and viscosity values and the antioxidant and antibacterial activities of the dispersions changed significantly with the addition of ZO to the polymer matrix. Changes in the properties of the dispersions suggested the presence of interactions between PVA or gelatin and ZO. Such interactions could affect the mechanical and water‐barrier properties of the films. ZO induced remarkable decreases in the tensile strength, elastic modulus, and swelling and increases in the elongation at break, solubility, and water‐vapor permeability of the films. Scanning electron microscopy analyses proved the impact of ZO on the film morphology, which affected the film properties, including the mechanical and water‐barrier properties. The addition of ZO to the polymer led to a coarse film microstructure because of the hydrophobic ZO aggregates, which produced discontinuities in the film matrix. ZO considerably increased the antioxidant and antibacterial activities of the dispersions. Pseudomonas aeruginosa was the most resistant bacteria. The improved antioxidant and antimicrobial activities of the PVA–ZO and gelatin–ZO indicated that such products could effectively be used as wound dressings. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45351.     

Controlled release from polyurethane films: Drug release mechanisms

In this study, polyurethane-films loaded with diclofenac were used to analyze the drug release kinetics and mechanisms. For this purpose, the experimental procedures were developed under static and dynamic conditions with different initial drug loads of 10, 20, and 30%. In the dynamic condition, to better simulate the biological flow, drug release measurements were investigated at flow rates of 7.5 and 23.5 ml/s. These values indicate the flow rate of the internal carotid artery (ICA) for a normal state of a body and for a person during the exercise, respectively. The experimental data were analyzed and adjusted by Higuchi, Korsmeyer–Peppas, First-order, zero-order, and Peppas–Sahlin models in order to understand the mechanisms contributed. Finally, drug release mechanisms were specified by investigating the model correlation coefficients. Experimental results showed that increasing the flow rate and initial drug loads enhance drug liberation. In addition, the rate of release is more influenced by the drug dosage in the static state. The analysis revealed that diffusion, burst, and osmotic pressure are the principal mechanisms contributed. Moreover, Fickian type was the dominant mechanism at all duration of release. However, it was discovered using Peppas–Sahlin model that the contribution of the diffusion mechanism decreases with increasing flow rate and initial dosage. Furthermore, the tests at different drug dosages showed that the number of stages in medication release profile is independent of the flow rate and the medicine percentage. One can conclude that the drug release kinetic in static state is more influenced by drug dosage compared with dynamic state.     

Throughput analysis of wireless-powered decode-and-forward relay systems with interference

Wireless Networks - This paper investigates the throughput of a wireless-powered dual-hop relaying system with the presence of co-channel interference. Specifically, an energy-constrained source...     

Investigating various effects of reformer gas enrichment on a natural gas-fueled HCCI combustion engine

Homogenous charge compression ignition (HCCI) combustion has the potential to work with high thermal efficiency, low fuel consumption, and extremely low NO_x-PM emissions. In this study, zero-dimensional single-zone and quasi-dimensional multi-zone detailed chemical kinetics models were developed to predict and control an HCCI combustion engine fueled with a natural gas and reformer gas (RG) blend. The model was validated through experiments performed with a modified single-cylinder CFR engine. Both models were able to acceptably predict combustion initiation. The result shows that the chemical and thermodynamic effects of RG blending advance the start of combustion (SOC), whereas dilution retards SOC. In addition, the chemical effect was stronger than the dilution effect, which was in turn stronger than the thermal effect. Furthermore, it was found that the strength of the chemical effect was mainly dependent on H₂ content in RG. Moreover, the amount of RG and concentration of species (CO–H₂) were varied across a wide range of values to investigate their effects on the combustion behavior in an HCCI engine. It was found that the H₂ concentration in RG has a more significant effect on SOC at lower RG percentages in comparison with the CO concentration. However, in higher RG percentages, the CO mass concentration becomes more effective than H₂ in altering SOC.