An Accurate PSO-GA Based Neural Network to Model Growth of Carbon Nanotubes

© 2017 Mohsen Asadnia et al. By combining particle swarm optimization (PSO) and genetic algorithms (GA) this paper offers an innovative algorithm to train artificial neural networks (ANNs) for the purpose of calculating the experimental growth parameters of CNTs. The paper explores experimentally obtaining data to train ANNs, as a method to reduce simulation time while ensuring the precision of formal physics models. The results are compared with conventional particle swarm optimization based neural network (CPSONN) and Levenberg-Marquardt (LM) techniques. The results show that PSOGANN can be successfully utilized for modeling the experimental parameters that are critical for the growth of CNTs

Cell sheet engineering: solvent effect on nanometric grafting of poly-n-isopropylacrylamide onto polystyrene substrate under ultraviolet radiation

Esmaeil Biazar1, MT Khorasani2, M Daliri31Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran; 2Biomaterial Department, Iran Polymer and Petrochemical Institute, Tehran, Iran; 3National Research Center for Genetic Engineering and Biotechnology, Tehran, IranBackground: The best solvent type and ratio for grafting of poly-n-isopropylacrylamide (PNIPAAm) on the surface of polystyrene is obtained under ultraviolet radiation. In this study, the effects of solvents, such as water, methanol, and their combinations, under ultraviolet radiation were investigated successfully.Method and results: Attenuated total reflection Fourier transform infrared analysis showed the existence of the graft PNIPAAm on the substrate for all samples resolved in solvents. The best solvent ratio and NIPAAm concentration for grafting was obtained with 40% NIPAAm concentrations resolved in a solvent of 9:1 (v/v) water/methanol (120%). Scanning electron microscopic and atomic force microscopic images clearly showed that a 10% increase of methanol to water would increase the amount of grafting. Surface topography and graft thickness in atomic force microscopic images of the grafted samples showed that the thickness of these grafts was about 600 nm. The drop water contact angles of the best grafted sample at 37°C and 4°C were 43.3° and 60.4°, respectively, which demonstrated the hydrophilicity and hydrophobicity of the grafted surfaces. Differential scanning calorimetric analysis also revealed the low critical solution temperature of the grafted sample to be 32°C. Thermoresponsive polymers were grafted to dishes covalently, which allowed epithelial cells to attach and proliferate at 37°C. The cells were also detached spontaneously without using enzymes when the temperature dropped below 4°C.Conclusion: MTT analysis also showed good viability of cells on the grafted samples, suggesting that this type of grafted material had potential as a biomaterial for cell sheet engineering.Keywords: nanometric grafting, solvent effect, poly-n-isopropylacrylamide, polystyrene film, ultraviolet radiatio

Three-dimensional accelerating AdS black holes in F(R)F(R) gravity

Considering a three-dimensional $C-$metric, we obtain the exact accelerating black holes in the $F(R)$ theory of gravity coupled with and without a matter field. First, we extract uncharged accelerating AdS black hole solutions in $F(R)$ gravity. Then, we study the effects of various parameters on metric function, roots, and the temperature of these black holes. The temperature is always positive for the radii less than $\frac{1}{\alpha }$, and it is negative for the radii more than $\frac{1}{\alpha }$. We extend our study by coupling nonlinear electrodynamics as a matter filed to $F(R)$ gravity to obtain charged black holes in this theory. Next, we evaluate the effects of different parameters such as the electrical charge, accelerating parameter, angular, $F(R)$ gravity, and scalar curvature on the obtained solutions, roots, and temperature of three-dimensional charged accelerating AdS black holes. The results indicate that there is a root in which it depends on various parameters. The temperature of these black holes is positive after this root.Comment: 11 pages, 3 figure

Thermomechanical buckling analysis of the e&p-fgm beams integrated by nanocomposite supports immersed in a hygrothermal environment

Due to the widespread use of sandwich structures in many industries and the importance of understanding their mechanical behavior, this paper studies the thermomechanical buckling behavior of sandwich beams with a functionally graded material (FGM) middle layer and two composite external layers. Both composite skins are made of Poly(methyl methacrylate) (PMMA) reinforced by carbon-nano-tubes (CNTs). The properties of the FGM core are predicted through an exponential-law and power-law theory (E&P), whereas an Eshelby–Mori–Tanaka (EMT) formulation is applied to capture the mechanical properties of the external layers. Moreover, different high-order displacement fields are combined with a virtual displacement approach to derive the governing equations of the problem, here solved analytically based on a Navier-type approximation. A parametric study is performed to check for the impact of different core materials and CNT concentrations inside the PMMA on the overall response of beams resting on a Pasternak substrate and subjected to a hygrothermal loading. This means that the sensitivity analysis accounts for different displacement fields, hygrothermal environments, and FGM theories, as a novel aspect of the present work. Our results could be replicated in a computational sense, and could be useful for design purposes in aerospace industries to increase the tolerance of target productions, such as aircraft bodies

Effect of plant cover on presence of Black Francolin (Francolinus francolinus) in Khouzestan Province, Southwestern Iran

Three of 6 subspecies of black francolins (Francolinus francolinus), are found throughout Iran. Habitat destruction and indiscriminate hunting as well as agricultural pesticides are among the most crucial factors threatening the populations of these birds in Khouzestan Province, southwestern Iran. Using plot sampling, this study aims to investigate different vegetative factors including plant species, percentage of species presence and dominant plant cover height on francolin presence. Sampling was carried out throughout 5 presence areas of black francolin and 2 areas lacking francolins (control areas). Results showed that frequency of Camels thorn (Alhagi cameloram), Cashew (Prosopis farcta) and African Salsola (Suaeda fruticosa) were higher in presence areas compared with other plant species. Using One Way ANOVA, it was determined that there was no significant difference between plant cover percent (P = 0.279) and dominant plant cover height (P = 0.316). However, difference of these two mentioned factors were significant in 4 seasons (P = 000 for cover height and P = 0.001 for cover percent). In fact, the highest black francolin presence was recorded at 15 – 67 and 4 – 48 for cover percent and cover height classes respectively

Efficacy of Hi-Lo Evac Endotracheal Tube in Prevention of Ventilator-Associated Pneumonia in Mechanically Ventilated Poisoned Patients

Background. Ventilator-associated pneumonia (VAP) is the most common health care-associated infection. To prevent this complication, aspiration of subglottic secretions using Hi-Lo Evac endotracheal tube (Evac ETT) is a recommended intervention. However, there are some reports on Evac ETT dysfunction. We aimed to compare the incidence of VAP (per ventilated patients) in severely ill poisoned patients who were intubated using Evac ETT versus conventional endotracheal tubes (C-ETT) in our toxicology ICU. Materials and Methods. In this clinical randomized trial, 91 eligible patients with an expected duration of mechanical ventilation of more than 48 hours were recruited and randomly assigned into two groups: (1) subglottic secretion drainage (SSD) group who were intubated by Evac ETT (n = 43) and (2) control group who were intubated by C-ETT (n = 48). Results. Of the 91 eligible patients, 56 (61.5) were male. VAP was detected in 24 of 43 (55.8) patients in the case group and 23 of 48 (47.9) patients in the control group (P = 0.45). The most frequently isolated microorganisms were S. aureus (54.10) and Acinetobacter spp. (19.68). The incidence of VAP and ICU length of stay were not significantly different between the two groups, but duration of intubation was statistically different and was longer in the SSD group. Mortality rate was less in SSD group but without a significant difference (P = 0.68). Conclusion. The SSD procedure was performed intermittently with one-hour intervals using 10 mL syringe. Subglottic secretion drainage does not significantly reduce the incidence of VAP in patients receiving MV. This strategy appears to be ineffective in preventing VAP among ICU patients. © 2016 Ahmad Ghoochani Khorasani et al

Quasi-3D Hyperbolic Shear Deformation Theory for the Free Vibration Study of Honeycomb Microplates with Graphene Nanoplatelets-Reinforced Epoxy Skins

A novel quasi-3D hyperbolic shear deformation theory (QHSDT) with five unknowns is here employed, together with the Hamilton's principle and the modified couple stress theory (MCST) to analyze the vibrational behavior of rectangular micro-scale sandwich plates resting on a visco-Pasternak foundation. The sandwich structure features a Nomex or Glass phenolic honeycomb core, and two composite face sheets reinforced with graphene nanoplatelets (GPLs). The effective properties of both face sheets are evaluated by means of the Halpin-Tsai and extended rule of mixture (ERM) micromechanical schemes. The governing equations of the problem are derived by applying the Hamilton's principle, whose solutions are determined theoretically according to a classical Navier-type procedure. A parametric study checks for the effect of different material properties, length-scale parameters, foundation parameters and geometrical properties of the honeycomb cells, and the reinforcing GPLs, on the vibration response of the layered structure, which can be of great interest for many modern engineering applications and their optimization design