Retracted: Drug release properties of poly(vinyl pyrrolidone)/acrylic acid copolymer hydrogels

The following article from the Journal of Applied Polymer Science, “Drug release properties of poly(vinyl pyrrolidone)/acrylic acid copolymer hydrogels,” by Abdullah S. Alarifi, published online on 14 February 2011 in Wiley Online Library (wileyonlinelibrary.com), and in Volume 120, pp. 3484‐3489, has been retracted by agreement between the journal's editors and Wiley Periodicals, Inc. The retraction has been agreed because of unacknowledged overlap with work previously published in the Arab Journal of Nuclear Sciences and Applications ( 2010 , 43, 366), as well as in Proceeding, 2nd International Conference on Radiation Sciences and Applications (Egyptian Society of Radiation Sciences and Applications: Marsa Alam, Egypt, 2010 ; p 362).     

Double Perforated Impingement Plate in Shell-and-Tube Heat Exchanger

This article presents a solution to a chronic problem causing repeated tube failure at shell-and-tube heat exchangers. The problem is related to the fouling process on the tubes' surface, which accumulates downstream from the impingement plate at the exchanger inlet nozzle within the first tube rows due to low velocity and vortices production. In fouling services, the suspended deposits, fouling, accumulates on the tubes' surface downstream from the impingement plate, causing under-deposit corrosion, raising the tubes' surface temperature due to lack of cooling, and accelerating fouling process. Under-deposit corrosion attacks tubes and causes repeated tube failure, costing a lot of money in terms of material, maintenance, and production losses. Normal practice of extending tube life and delaying their failure is to upgrade the tubes' metallurgy. So the article objective is to present an economical solution option through modifying the impingement plate in the shell-and-tube heat exchangers where the impingement plate is recommended by the Tubular Exchanger Manufacturers Association (TEMA). The impingement modification is to replace the solid conventional impingement plate with double spaced plates having offset holes, called double perforated impingement plates (DPIP). The objective of this work can be met by comparing the simulation of the shell-side inlet flow distribution around the conventional and modified (DPIP) impingement plates and ensuring enhancement of the flow pattern distribution at the area behind the impingement plates. Since experimental work in flow investigation is time-consuming and costly, computational fluid dynamics (CFD) Fluent software was implemented as a cost-effective helpful tool to conduct the simulation for comparison purposes. The modified impingement plate, DPIP, will destroy vortices created behind the conventional plate, retarding fouling accumulation. DPIP will enhance shell-side flow distribution downstream from the impingement plate and will stop fouling accumulation on the tubes to prevent under-deposit corrosion.     

Intelligent Forensic Investigation Using Optimal Stacked Autoencoder for Critical Industrial Infrastructures

Industrial Control Systems (ICS) can be employed on the industrial processes in order to reduce the manual labor and handle the complicated industrial system processes as well as communicate effectively. Internet of Things (IoT) integrates numerous sets of sensors and devices via a data network enabling independent processes. The incorporation of the IoT in the industrial sector leads to the design of Industrial Internet of Things (IIoT), which find use in water distribution system, power plants, etc. Since the IIoT is susceptible to different kinds of attacks due to the utilization of Internet connection, an effective forensic investigation process becomes essential. This study offers the design of an intelligent forensic investigation using optimal stacked autoencoder for critical industrial infrastructures. The proposed strategy involves the design of manta ray foraging optimization (MRFO) based feature selection with optimal stacked autoencoder (OSAE) model, named MFROFS-OSAE approach. The primary objective of the MFROFS-OSAE technique is to determine the presence of abnormal events in critical industrial infrastructures. The MFROFS-OSAE approach involves several subprocesses namely data gathering, data handling, feature selection, classification, and parameter tuning. Besides, the MRFO based feature selection approach is designed for the optimal selection of feature subsets. Moreover, the OSAE based classifier is derived to detect abnormal events and the parameter tuning process is carried out via the coyote optimization algorithm (COA). The performance validation of the MFROFS-OSAE technique takes place using the benchmark dataset and the experimental results reported the betterment of the MFROFS-OSAE technique over the recent approaches interms of different measures.     

Carbonization behavior of oxidized viscose rayon fibers in the presence of boric acid–phosphoric acid impregnation

The oxidation and carbonization stages of viscose rayon fibers were performed in the presence of 3 % phosphoric acid and 4 % boric acid (PA–BA) impregnation. The results showed that PA–BA impregnation enhanced thermal stability and prevented the evolution of volatile by-products. During the oxidation stage carried out at 250 °C, the cellulose II crystalline structure was totally lost due to the decrystallization process. Carbonization was carried out in a pure nitrogen atmosphere at temperatures ranging from 600 to 1000 °C. The results obtained from the fiber thickness, linear density, carbon fiber yield, elemental analysis, volume density, X-ray diffraction, infrared (IR) and Raman spectroscopy, tensile testing, and electrical conductivity measurements showed that the carbonization temperature had a significant effect on the structure and properties of the resulting carbon fibers. Carbon fibers obtained from the oxidized viscose rayon fibers showed physical and chemical transformations with increasing carbonization temperature and were characterized by a reduction in fiber thickness and linear density values due to the removal of non-carbon elements together with increases in the carbon content, carbon to hydrogen ratio (C/H), volume density, tensile strength, tensile modulus, and electrical conductivity values. X-ray diffraction analysis showed that the interplanar d-spacing (d ₀₀₂) decreased, and that the apparent crystallite thickness (L _c) and the apparent crystallite width (L _a) increased with increasing temperature. IR spectroscopy in agreement with the elemental analysis showed the total loss of OH, CH, C=O, CH₂, C–O, and C–O–C groups arising from the completion of dehydration and dehydrogenation reactions indicating total elimination of the cellulose structure and the formation of amorphous carbon during high temperature treatment.     

Formulation of chemically reduced graphene oxide assembly with poly(4‐vinyl pyridine) through noncovalent interaction

Soluble chemically reduced graphene oxide (RGO)/poly(4‐vinyl pyridine) (P4VP) assembly was attempted by totally noncovalent approach. Chemical reduction of P4VP/GO mixture by hydrazine produced soluble RGO/P4VP assembly with long term stability. Prepared RGO/P4VP assembly showed pH‐dependent variation of optical transmittance. Transmittance of RGO/P4VP assembly solution at pH 2.0 dramatically increased more than 200% of transmittance of assembly at pH 6. This optical transmittance change was fully reversible. The detailed morphological features of assemble was evaluated by dynamic light scattering (DLS) and atomic force microscopy (AFM). It is estimated that RGO/P4VP assemblies were well separated each other at pH 6, enabling much higher optical absorption of RGO plates. At pH 2, protonation of pyridine ring occurs and this might hamper effective noncovalent interaction between RGO plate and protonated P4VP chains, forming bigger aggregates having less chance for optical absorption. This pH‐dependent optical modulation of RGO/P4VP assembly can be useful for the designing of pH‐sensor, removable nanocatalyst, and targeted drug delivery, etc. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2538–2543, 2013     

Frictional material selection of dry clutch disc based on the weighted factor and finite element methods

The main task of the frictional facing of a clutch disc is to transfer the power from the driving to the driven parts. High frictional heat will be generated when the frictional facing comes into contact with the moving surfaces (flywheel and pressure plate). In this research paper, the selection of the frictional-facing material of the clutch disc has been investigated to obtain the optimal thermal behavior of the clutch system. It used five different frictional materials (St37-2, HCC, G95, LUK, and Tiger), and then applied the Weighted Factor Method to find the optimal frictional material that can be used in the clutch disc. In the second part, an axisymmetric finite element (FE) model has been developed to simulate the working of the clutch system during the heating phase. A comparison was made between the results of the thermal problem using the FE method and the Weighted Factor Method, where a high agreement was obtained between them to determine the optimal frictional material for the clutch disc. It was found that the frictional material (HCC) is the superior one with the highest performance index equal to 90.7 and the lowest values of the maximum temperature (353.7 K). In contrast, the frictional material (St37-2) is the poorest one, with the lowest performance index equal to 30.7 and the highest values of the maximum temperature (378.2 K).     

Transfer learning for histopathology images: an empirical study

Neural Computing and Applications - Histopathology imaging is one of the key methods used to determine the presence of cancerous cells. However, determining the results from such medical images is...