Extraction of essential oils from Bunium persicum Boiss. using superheated water

A comparative study of superheated water extraction (SWE) with two conventional volatile isolation methods including hydrodistillation and Soxhlet extraction was performed on Bunium persicum Boiss. Influence of operating conditions such as temperatures from 100 to 150 °C, mean particle size from 0.5 to 1.0 mm and flow rates from 2 to 4 mL/min on the extraction process was investigated. The experiments were carried out using a laboratory-built apparatus. Separation and identification of the components were carried out by GC-FID and GC/MS. The optimum extraction efficiency for SWE was determined at 125 °C, 4 mL/min and 0.5 mm. At these operating conditions, the extraction efficiency was lower than hydrodistillation and Soxhlet extraction methods, but SWE was quicker and with respect to the valuable oxygenated components, it was more selective.     

Optimization of proteases pretreatment on natural dyeing of wool using response surface methodology

Natural dyes and enzymes have attracted a lot of attention due to their non-hazardous nature. In this research, wool fabrics were pretreated with the commercial protease at different concentrations over various times. The dyeing process was then carried out on the treated fabrics with the commercial madder and cochineal. Also, the central composite design analysis was used to design the relation between dye exhaustion and some properties of dyed wool including tensile strength, alkaline solubility, water drop absorption, and weight loss based on Design of Expert software. The response surface methodology was also applied to find the optimum conditions for the wool fabric pretreatment. The scanning electron microscopy was employed to indicate the influences of proteases on the fabric surface. The optimized proteases pretreatment on the wool surfaces has considerably improved the absorption of madder and cochineal and minimized the damage to appropriate physical properties. The adsorption kinetic of madder and cochineal on enzymatic wool fiber was fitted with a pseudo-second-order model. The rate of dyeing at different temperatures, as well as the values of standard affinity, entropy, and enthalpy, was calculated. The activation energy of dyeing with madder and cochineal at different temperatures are 23.79 and 30.96 kJ/mol, respectively, considering that these values are in the typical activation energy for physisorption. It was also found that wash, light, wet and dry rub fastness properties of the samples dyed along with protease have not changed significantly. This can be easily scaled up in the industry as a simple method using the commercial materials.     

Promotional effect of Mg in trimetallic nickel-manganese-magnesium nanocrystalline catalysts in CO2 reforming of methane

In the present paper, the dry reforming reaction was studied over the 10 wt%Ni-3wt.%Mn-x wt.% Mg (x = 2, 4 and 6 wt%) catalysts supported on γ-Al₂O₃ with mesoporous structure. The physicochemical characteristics of the samples were determined by XRD, BET, TPO, and SEM techniques. Mesoporous γ-Al₂O₃ carrier with the high BET area (186 m²/g) was synthesized by a simple sol–gel method and the Ni, NiMn and Mg promoted catalysts possessed nanocrystalline mesoporous structure with the BET area in the range of 127–176 m²/g. The average pore radius of the prepared catalysts were smaller than 11 nm. All the synthesized samples exhibited a CH₄ conversion in the range of 60–65% at 700 °C. The small differences in methane conversion in all catalysts could be related to the same nickel loading. According to the TPR results, the Mg addition caused an increase in the reducibility of the nickel catalyst and the Mg-promoted sample exhibited a higher conversion compared to the monometallic catalyst, due to its higher reducibility. The results showed that the textural characteristics of the catalysts were affected by the content of Mg. The results indicated that the NiMn/Al₂O₃ catalyst promoted by 4 wt% Mg showed the highest CH₄ conversion in all studied reaction temperatures (550–700 °C). Furthermore, only one oxidation peak was detected for all catalysts in TPO analysis, which was related to the filamentous form carbon. The 10Ni/Al₂O₃ and 10Ni3Mn4Mg/Al₂O₃ catalysts exhibited the highest and the lowest amount of deposited filamentous carbon, respectively. The 10Ni3Mn4Mg/Al₂O₃ catalyst was stable during the 20 h time on stream without any decline in CH₄ conversion.     

Experimental investigation on the behavior of corrugated steel shear wall subjected to the different angle of trapezoidal plate

Studies on corrugated steel shear walls (CSSWs) generally indicate noticeable increase of energy absorption, as well as increasing shear buckling capacity of corrugated plates being more likely rather than the flat plates. In this paper, the effect of variation in the angle of trapezoidal plate on the behavior of CSSWs has extensively been investigated. Three specimens of CSSW with 1 story and single bay in half scale are tested under cyclic load. The observations of experiment do indicate that stress concentration has been increased in the corner of subpanels, by increasing of the corrugation angle. Development of the tensile field and wall yield and damage depends on the geometry of the plate. By increasing the corrugation angle, the stiffness and energy dissipation decrease; in addition, large loss of strength takes place. Comparing the numerical and experimental results indicates that for a closer look at behavior of trapezoidal CSSWs, fracture mechanics, fatigue, and damping of materials should be considered by numerical analysis.     

Measuring social media activity of scientific literature: an exhaustive comparison of scopus and novel altmetrics big data

This paper measures social media activities of 15 broad scientific disciplines indexed in Scopus database using Altmetric.com data. First, the presence of Altmetric.com data in Scopus database is investigated, overall and across disciplines. Second, a zero-truncated negative binomial model is used to determine the association of various factors with increasing or decreasing citations. Lastly, the effectiveness of altmetric indices to identify publications with high citation impact is comprehensively evaluated by deploying area under the curve (AUC)—an application of receiver operating characteristic. Results indicate a rapid increase in the presence of Altmetric.com data in Scopus database from 10.19% in 2011 to 20.46% in 2015. It was found that Blog count was the most important factor in the field of Health Professions and Nursing as it increased the number of citations by 38.6%, followed by Twitter count increasing the number of citations by 8% in the field of Physics and Astronomy. The results of receiver operating characteristic show that altmetric indices can be a good indicator to discriminate highly cited publications, with an encouragingly AUC = 0.725 between highly cited publications and total altmetric count. Overall, findings suggest that altmetrics can be used to distinguish highly cited publications. The implications of this research are significant in many different directions. Firstly, they set the basis for a further investigation of altmetrics efficiency to predict publications impact and most significantly promote new insights for the measurement of research outcome dissemination over social media.     

A fast method for process reliability analysis of CNFET-based digital integrated circuits

Due to aggressive technology scaling in electronic of digital integrated circuits, the circuit reliability is becoming an ever-increasing challenge. In nanoscale technologies, the physical and chemical properties of materials are fundamentally different compared to the larger scales. Therefore, it is necessary to revise the conventional reliability assessment techniques considering their applicability to nanoscale integrated circuits. This paper presents a method for evaluating the circuit reliability at the transistor level of abstraction considering the physical characteristics of the transistors. The proposed method considers various parameters, including the probability of different types of a transistor failure, the topology of logic gates and the logical values of the applied input vectors. Experimental results show that the proposed approach provides accurate transistor-level circuit reliability evaluations (with < 4% inaccuracy) as compared to a reference method based on Monte Carlo HSPICE simulations in addition to more than 800 times speedup. Moreover, to show the comprehensiveness and extensibility of the proposed reliability analysis method for the technologies beyond conventional MOSFETs, it is applied to carbon nanotube field-effect transistor (CNFET) technology as one of the most promising candidates for future CMOS circuits. The obtained results re-acknowledge that in order to achieve a more accurate reliability estimation approach for CNFET circuits, it is necessary to consider the open and short failure probability values individually instead of considering them in the form of a single transistor failure probability.     

Production of polyvinylpyrrolidone/chiral diacid modified nanocrystalline Mg‐substituted fluorapatite nanocomposites: Morphological and thermal characterization

The main objective of this work was the production of novel polyvinylpyrrolidone/diacid modified Mg‐substituted fluorapatite (DM‐MFA) nanocomposites (NC)s, by sonication process. Mg‐substituted fluorapatite (MFA) powders with a chemical composition of Ca_9.5Mg_0.5(PO₄)₆F₂ were prepared by mechanical alloying technique. Initially, surface of MFA was modified by bioactive chiral diacid monomer, N‐trimellitylimido‐l ‐leucine as a coupling agent to form DM‐MFA nanoparticles. DM‐MFA NPs were utilized as a filler, to give the NCs with potential bioactivity. Examination of transmission electron microscopy (TEM), and field emission scanning electron microscopy (FE‐SEM) microphotographs displayed that, there is no aggregation of a large quantity of particles. The above NCs showed rather improved thermal stability compared with pure polymer. The improvement of thermal behavior was related to the uniform and good dispersion of DM‐MFA in the polymer matrix as well as the strong hydrogen bonding between C?O of PVP and OH of DM‐MFA. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44254.     

Preparation of nanocrystalline Ni/Al2O3 catalysts with the microemulsion method for dry reforming of methane

Mesoporous nanocrystalline nickel‐alumina catalysts with high surface area were prepared by a microemulsion (ME) method and were employed in methane reforming with carbon dioxide for syngas production. The catalysts were characterized by X‐ray diffraction (XRD), Brunauer‐Emmett‐Teller surface area analysis (BET), temperature‐programmed reduction (TPR), temperature‐programmed oxidation (TPO), and scanning electron microscopy (SEM) techniques. The results showed that the catalysts possessed mesoporous structure with high surface area (> 250 m² · g^?1) and small crystallite size (～5 nm). The catalytic results revealed high activity and stability for the prepared catalysts. In addition, the effect of feed ratio and GHSV on catalytic performance was investigated.     

Synthesis of lysozyme imprinted column with macroporous structure and enhanced selectivity: Utilization of cryogelation technique and electrostatic functional monomers

Applicability of molecularly imprinted polymers (MIP) in conventional protein separation processes demands monolithic construction of columns with macroporous structure in addition to the high specificity and adsorption capacity. In this study, therefore, lysozyme (Lyz) imprinted monolithic cryogel columns were synthesized using electrostatic functional monomers (EFMs) to provide strong interactions between template and polymer, leading to specific recognition and capture of Lyz. SEM images and FTIR spectroscopy analysis confirmed the macroporous structure and presence of EFMs in the samples. Adsorption isotherms, heterogeneity, and breakthrough curves as well as selectivity of the molecularly imprinted cryogels (EFMs‐MIC) and non‐imprinted cryogels (EFMs‐NIC) were investigated. Results showed effective imprinting with a maximum adsorption capacity of 211 mg/g and a high imprinting factor (IF) of 4.2 at low Lyz concentrations. A high relative selectivity coefficient of 7.24 was obtained for Lyz over cytochrome c, a competing protein, indicating that the imprinted sites could well distinguish Lyz. Reusability of MICs was also examined, where insignificant changes were observed in the cryogel adsorption/desorption characteristics after four cycles. Therefore, it is suggested to use EFMs and cryogelation in the synthesis of imprinted monolithic cryogels column for application in conventional protein separation processes. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42880.