Fabrication of superparamagnetic adsorbent based on layered double hydroxide as effective nanoadsorbent for removal of Sb (III) from water samples

In this study, the superparamagnetic adsorbent as Fe@Mg‐Al LDH was synthesised by different methods with two steps for the removal of heavy metal ions from water samples. An easy, practical, economical, and replicable method was introduced to remove water contaminants, including heavy ions from aquatic environments. Moreover, the structure of superparamagnetic adsorbent was investigated by various methods including Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and vibrating sample magnetometer. For better separation, ethylenediaminetetraacetic acid ligand was used, forming a complex with antimony ions to create suitable conditions for the removal of these ions. Cadmium and antimony ions were studied by floatation in aqueous environments with this superparamagnetic adsorbent owing to effective factors such as pH, amount of superparamagnetic adsorbent, contact time, sample temperature, volume, and ligand concentration. The model of Freundlich, Langmuir, and Temkin isotherms was studied to qualitatively evaluate the adsorption of antimony ions by the superparamagnetic adsorbent. The value of loaded antimony metal ions with Fe@Mg‐Al LDH was resulted at 160.15 mg/g. The standard deviation value in this procedure was found at 7.92%. The desorption volume of antimony metal ions by the adsorbent was found to be 25 ml. The thermodynamic parameters as well as the effect of interfering ions were investigated by graphite furnace atomic absorption spectrometry.     

Error evaluation on experimental stress–strain curve obtained from tube bulging test

To get precise material data for advanced numerical modelling of tube hydroforming process, the tube bulging test is recommended. Stresses and strains in the tube cannot be evaluated easily and several approaches have been proposed. A review is proposed and points out their advantages and drawbacks.     

Mechanism of production of intestinal secretion by negative luminal pressure

The relationships between luminal hydrostatic pressure and fluid transport by dog jejunum in vivo studied as a sheet in the Wells clamp were compared with quantitative predictions from a model proposed for the mechanism of the secretion produced by elevated venous pressure. According to the model, the secretion produced by increasing venous pressure and the secretion produced by negative luminal pressure are both passive filtrates contingent on a transepithelial pressure of a few centimeters of H2O. We consider that the agreement between the observed and predicted responses to luminal pressure provides strong support for the model. In particular, a) the observations displayed a predicted gross asymmetry in rates of fluid transfer with isotonic fluids depending on whether the luminal pressure was positive or negative; b) the observed magnitude of the negative luminal pressure required for the onset of secretion agreed with predictions; and c) the secretion contained significant amounts of protein at about 25% of the plasma concentration.     

Nanoparticle Coating for Advanced Optical,Mechanical and Rheological Properties

Primary titania nanoparticles were coated with ultrathin alumina films using Atomic Layer Deposition (ALD). The deposited films were highly uniform and conformal with an average growth rate of 0.2 nm per coating cycle. The alumina films eliminated the surface photocatalytic activity of titania nanoparticles, while maintained their original extinction efficiency of ultraviolet light. Deposited films provided a physical barrier that effectively prevented the titania surface from oxidizing organic material whereas conserving its bulk optical properties. Parts fabricated from coated powders by pressureless sintering had a 13 % increase in surface hardness over parts similarly fabricated from uncoated particles. Owing to its homogeneous distribution, the secondary alumina phase suppressed excessive grain growth. Alumina films completely reacted during sintering to form aluminum titanate composites, as verified by XRD. Coated particles showed a pseudoplastic behavior at low shear rates due to modified colloidal forces. This behavior became similar to the Newtonian flow of uncoated nanoparticle slurries as the shear rate increased. Suspensions of coated particles also showed a decreased viscosity relative to the viscosity of uncoated particle suspensions.     

Numerical electromagnetic field analysis on lightning surgeresponse of tower with shield wire

Lightning surge characteristics of a transmission line comprising a tower, a shield wire and phase conductors are studied with the help of NEC-2. A tower struck by a lightning stroke behaves as an antenna until a traveling wave makes several roundtrips in the tower. During this interval, the tower footing impedance appears to be higher than the footing resistance, and the coupling coefficient between a shield wire and a phase conductor is much lower than that in the TEM mode. These affect the estimation of insulator voltages of transmission towers subject to lightning currents having short rise times. On the basis of these findings, the parameters in the multistory tower model, which has been used widely in EMTP multi-conductor analyzes, are newly proposed     

Modification of interparticle forces for nanoparticles using atomic layer deposition

Silica and titania nanoparticles were individually coated with ultrathin alumina films using atomic layer deposition (ALD) in a fluidized bed reactor. The effect of the coating on interparticle forces was studied. Coated particles showed increased interactions which impacted their flowability. This behavior was attributed to modifications of the Hamaker coefficient and the size of nanoparticles. Stronger interparticle forces translated into a larger mean aggregate size during fluidization, which increased the minimum fluidization velocity. A lower bed expansion was observed for coated particles due to enhanced interparticle forces that increased the cohesive strength of the bed. Increased cohesiveness of coated powders was also determined through angle of repose and Hausner index measurements. The dispersability of nanopowders was studied through sedimentation and z-potential analysis. The optimum dispersion conditions and isoelectric point of nanoparticle suspensions changed due to the surface modification. A novel atomic force microscope (AFM) technique was used to directly measure interactions between nanoparticles dispersed on a flat substrate and the tip of an AFM cantilever. Both Van der Waals and electrostatic interactions were detected during these measurements. Long and short range interactions were modified by the surface coating.     

A multiprocessor based heuristic for multi-dimensional multiple-choice knapsack problem

This paper presents a multiprocessor based heuristic algorithm for the Multi-dimensional Multiple Choice Knapsack Problem (MMKP). MMKP is a variant of the classical 0–1 knapsack problem, where items having a value and a number of resource requirements are divided into groups. Exactly one item has to be picked up from each group to achieve a maximum total value without exceeding the resource constraint of each type. MMKP has many real world applications including admission control in adaptive multimedia server system. Exact solution to this problem is NP-Hard, and hence is not feasible for real time applications like admission control. Therefore, heuristic solutions have been developed to solve the MMKP. M-HEU is one such heuristic, which solves the MMKP achieving a reasonable percentage of optimality. In this paper, we present a multiprocessor algorithm based on M-HEU, which runs in O(T/p+s(p)) time, where T is the time required by the algorithm using single processor, p is the number of processors and s(p), a function of p, is the synchronization overhead. We also present the worst-case analysis of our algorithm, the computation of the optimal number of processors as well as the lower bound of the total value that can be achieved by the heuristic.     

Target search of burglars: A revised economic model

Abstract. This article investigates home attributes that attract residential burglars in choosing a target. These attributes are the location of the home, its physical appearance, demographic characteristics of the residents, and the security precautions present. The theoretical foundation of the empirical model is the criminal utility maximization behavior that considers costs and benefits as formulated by Becker. However, this article introduces to the model the spatial dimension of the burglar's search for a target. The incidence of burglary is the dependent variable and is measured in a dichotomy scale. The empirical analysis utilizes a survey database of burgled and non-burgled homes that was conducted by the researchers. A logit model is used for the investigation, and the effects of the explanatory variables are calculated as probabilities. The database is unique in the wealth of attributes of individual homes that are relevant to burglars'decision process.     

Plasma surface modification and characterization of collagen‐based artificial cornea for enhanced epithelialization

Argon plasma treatment enhanced the attachment of epithelial cells to a collagen‐based artificial cornea crosslinked using glutaraldehyde (GA) and glutaraldehyde‐polyethylene oxide dialdehyde (GA‐PEODA) systems. The epithelialization of untreated and treated surfaces was evaluated by the seeding and growth of human corneal epithelial cells. Characterization of polymer surface properties such as surface hydrophilicity and roughness was also made by contact angle measurement and atomic force microscopy, respectively. Contact angle analysis revealed that the surface hydrophilicity significantly increased after the treatment. In addition, AFM characterization showed an increase in surface roughness through argon plasma treatment. Based on the biological and surface analysis, argon plasma treatment displays promising potential for biocompatibility enhancement of collagen‐based artificial corneas. It was also found that the cell attachment to artificial cornea surfaces was influenced by the combined effects of surface chemistry (i.e., surface energy), polymer surface morphology (i.e., surface roughness), and polar interactions between functional groups at the polymer surface and cell membrane proteins. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007