Conversion of Pyrolysis Fuel Oils by a Dielectric Barrier Discharge Reactor in the Presence of Methane and Ethane

Pyrolysis fuel oil cracking by low‐temperature plasma was investigated in a dielectric barrier discharge reactor at ambient pressure. The promoting effect of methane and ethane in the formation of products was evaluated by altering the working gas from methane to ethane. In addition, the production of hydrocarbons and hydrogen was analyzed. The main parameters were working gas type, flow rate, and applied voltage. Increasing the applied voltage enhanced the production rate of valuable petrochemical compounds like gas and liquid. Alteration of the working gas flow rate led to a higher production rate of H₂, C₂, C₃, and C₄. Chemical investigations were performed by optical emission spectroscopy of plasma and the main mechanisms are described.     

Continuum-molecular modelling of graphene

In the present contribution we address the modeling of graphene membranes using a hierarchical modeling strategy to bridge the scales required to describe and understand the material. Quantum Mechanical (QM) and optimized Molecular Mechanical (MM) models are used to describe details on the nanoscale, while a multiscale continuum mechanical method is used to model the graphene response at the device or micrometer scale. The complete method is obtained on the basis of the Cauchy Born Rule (CBR), where the continuum model is coupled to the atomic field via the CBR and a local discrete fluctuation field. The MM method, often used to model carbon structures, involves the Tersoff–Brenner (TB) potential; however, when applying this potential to graphene with standard parameters one obtains material stress behavior much weaker than experiments. On the other hand, the more fundamental Hartree Fock and Density Functional Theory (DFT) methods are computationally too expensive and very limited in terms of their applicability to model the geometric scale at the device level. In this contribution a simple calibration of some of the TB parameters is proposed in order to reproduce the results obtained from QM calculations. Subsequently, the fine-tuned TB-potential is used for the multiscale modeling of a nano indentation sample, where experimental data are available. Effects of the mechanical response after the calibration are demonstrated.     

The capability of SnTe QDs as QDSCs working in the visible–NIR region and the effects of Eu-doping on improvement of solar cell parameters

The current work is the first effort to show the capability of SnTe quantum dots (QDs) in as a quantum dots solar cell device, which work in visible-near-infrared (NIR) regions, and improvement of the solar cell parameters by Eu-doping. Undoped and Eu-doped SnTe QDs with different Eu concentration from 2 to 6% were synthesized by a co-precipitation method. X-ray diffraction patterns and transmission electron microscopy images indicated that, crystallite and particle size of the samples were decreased by increasing of Eu content. Fourier-transform infrared (FTIR) and Raman spectroscopy results revealed that some vibration modes were appeared and disappeared by Eu-doping. According to the photoluminescence (PL) results, PL intensity of the doped sample was enhanced significantly in the green region in comparison to the PL intensity of the undoped sample. Ultraviolet-visible-near infrared spectroscopy results indicated that the pristine and Eu(2%)-doped samples don’t have any absorption in the visible region, while, Eu(4% and 6%)-doped SnTe QDs showed a good absorption in this region. Photocurrent measurements showed that, unlike the pristine and Eu(2%)-doped QDs, Eu(4% and 6%)-doped SnTe QDs showed a high responsivity in the visible and NIR regions. Solar cell measurements showed that, solar cell parameters such as short current density (J_sc), open circuit voltage (V_oc), conversion efficiency values (η), and fill factor (FF) were increased by Eu-doping.     

A blackboard approach towards integrated Farsi OCR system

An integrated OCR system for Farsi text is proposed. The system uses information from several knowledge sources (KSs) and manages them in a blackboard approach. Some KSs like classifiers are acquired a priori through an offline training process while others like statistical features are extracted online while recognizing. An arbiter controls the interactions between the solution blackboard and KSs. The system has been tested on 20 real-life scanned documents with ten popular Farsi fonts and a recognition rate of 97.05% in word level and 99.03% in character level has been achieved. An erratum to this article can be found at     

Preparation of silica-decorated graphene oxide nanohybrid system as a highly efficient reinforcement for woven jute fabric reinforced epoxy composites

In the current work, silica-decorated graphene oxide (SiO₂@GONPs) nanohybrids were used to reinforce the jute fiber/epoxy (JF/EP) composite. Tetraethylorthosilicate (TEOS) was utilized to prepare the SiO₂@GONPs using a facial route. The results of Fourier-transform infrared spectroscopy (FTIR), atomic force microscopy, and elemental X-ray mapping confirmed the successful synthesis of SiO₂@GONPs nanohybrids. Herein, the effects of SiO₂@GONPs loading (0, 0.1, 0.3, and 0.5 wt%) on the mechanical behavior of the JF/EP composite were investigated with emphasis on the flexural and high-velocity impact properties. The results revealed that reinforcement of matrix with 0.3 wt% SiO₂@GONPs enhanced the flexural strength of the JF/EP composite by about 40%. The energy absorption capability and impact limit velocity of the 0.3 wt% SiO₂@GONPs-filled JF/EP composite were 61 and 28%, respectively, higher than those of the neat specimen. Compared to the untreated-GONPs, the SiO₂@GONPs nanohybrid demonstrated an evident superiority in improving the mechanical properties of the JF/EP composite at the same loading. Evaluation of the fracture surfaces of the multiscale composites revealed that the improved fiber-matrix interfacial bonding was the basic mechanism of fracture in these specimens.     

Effect of microwave plasma torch on the pyrolysis fuel oil in the presence of methane and ethane to increase hydrogen production

Pyrolysis fuel oil (PFO) processing by microwave plasma torch was developed for the production of hydrogen. The PFO cracking process was performed at atmospheric pressure in the absence of catalyst and effect of plasma gas on the production rate of hydrogen and light hydrocarbons (C₂–C₄) was evaluated. In the first step, effect of the applied power and the working gas flow rate was investigated. In the second step, the applied power and working gas rate were set to 650 W and 4000 sccm, respectively, which were provided by combining methane or ethane as 0%, 2.5%, 7.5%, and 20% with argon. By increasing the percentage of the existing methane in argon, production rate of the sum of the light hydrocarbons was increased and that of hydrogen was reduced, but it was more than the case when argon was applied alone. By increasing ethane percentage, hydrogen production and light hydrocarbon rate were increased. The best conditions of the plasma gas for producing hydrogen at the power of 650 W were obtained as 5CC PFO feed, 2500 sccm (80%) argon, and 500 sccm (20%). The hydrogen production rate in optimized conditions was 2343.16SCCM with selectivity of 84.41%. Sum of the obtained hydrocarbons in this test was 434.25 sccm. Another parameter in the present study was the feed volume processed by plasma. In this case, 5 cc, 3 cc, and 1 cc of the feed were tested when the plasma gas was 3000 sccm argon with the power of 650 W. The results showed that, by increasing the feed, the products were increased. In the processing of 5 cc feed with plasma, 896.41 sccm hydrogen and 61 sccm light hydrocarbon were produced.     

The removal of cationic dyes from aqueous solutions by adsorption onto pistachio hull waste

The efficacy of pistachio hull powder (PHP) prepared from agricultural waste was investigated in this study as a novel adsorbent for the elimination of dye molecules from contaminated streams. Removal of methylene blue (MB) as a cationic model dye by PHP from aqueous solution was studied under different experimental conditions. The selected parameters were solution pH (2–10), PHP dosage (0.5–3 g/L), MB concentrations (100–400 mg/L), contact time (1–70), and solution temperature (20–50 °C). The experimental results indicated that the maximum MB removal could be attained at a solution pH of 8. The dosage of PHP was also found to be an important variable influencing the MB removal percentage. The removal efficiency of MB improved from 94.6 to 99.7% at 70 min contact time when the MB concentration was decreased from 300 to 100 mg/L at a pH and PHP dosage of 8 and 1.5 g/L, respectively. The kinetic analysis showed that the pseudo-second-order model had the best fit to the experimental data. The Langmuir equation provided the best fit for the experimental data of the equilibrium adsorption of MB onto PHP at different temperatures. In addition, the maximum adsorption capacity increased from 389 to 602 mg/g when the temperature was increased from 20 to 50 °C. The thermodynamic evaluation of MB adsorption on PHP revealed that the adsorption phenomenon under the selected conditions was a spontaneous physical process. Accordingly, pistachio hull waste was shown to be a very efficient and low-cost adsorbent, and a promising alternative for eliminating dyes from industrial wastewaters.