Sawdust--a green and economical sorbent for the removal of cadmium (II) ions

The ability of sawdust (treated and untreated) waste, a waste material derived from the commercial processing of cedrus deodar wood for furniture production, to remove/preconcentrate Cd(II) ions from aqueous solution was determined. Sorption was found to be rapid (approximately 97% within 8 min). The binding of metal ions was found to be pH dependent, optimal sorption accruing at around pH 4-8. Potentiometric titrations of sawdust revealed two distinct pK(a) values, the first having the value similar to carboxylic groups (3.3-4.8) and second comparable with that of amines (8.53-10.2) with the densities 1.99 x 10(-4) and 7.94 x 10(-5), respectively. Retained Cd(II) ions were eluted with 5 ml of 0.1 mol l(-1) HCl. Detection limit of 0.016 microg ml(-1) was achieved with enrichment factors of 120. Recovery was quantitative using sample volume of 600 ml. The Langmuir and D-R isotherm equations were used to describe partitioning behavior for the system at different temperatures. Kinetic and thermodynamic behavior of sawdust for Cd(II) ions removal was also studied.     

A new method of reinforcing graphene nanoplatelets in glass/epoxy composites

This research aims to develop a method for the amalgamation of graphene nanoplatelets in glass/epoxy composites. The poor interface bonding between the fiber and matrix is critical and hinders the full performance of the composites. Glass fabric and epoxy were used as reinforcement and matrix in the composite, respectively. Graphene nanoplatelets were utilized as an additional nano-materials filler for the composites. Glass/graphene/epoxy and glass/epoxy composites were fabricated via vacuum infusion molding. The new method of applying graphene nanoplatelets as secondary reinforcement in the composite was developed based on proper functionalization in the sonication process. The physical, tensile, flexural, and short beam interlaminar properties of fabricated composites were examined to analyze the method's effectiveness. The results showed that density decreased by around 5 %; however, thickness increased by around 34 % after introducing graphene nanoplatelets into the composites. The tensile strength and modulus of the composites declined by approximately 19 %, on the other hand, flexural strength and modulus increased by around 63.3 % and 8.3 %, respectively, after the addition of graphene nanoplatelets into the composites. Moreover, interlaminar shear strength of the composite was enhanced by approximately 50 %.     

Spin glass behaviour in the Co2−xZnxTiO4 compound

A.c. susceptibility measurements were carried out on the disordered spinel system Co_2–x Zn _x TiO₄ (0<x<1) between 10 and 80 K. Our measurements show three peaks in the versus T curve for Co₂TiO₄ and CoZnTiO₄ compounds. In both compounds two peaks are very close to each other, indicating that the Néel and semi-spin glass temperatures are very close. A third peak indicates the presence of the semi-spin glass to spin glass transition. In Co_1.5Zn_0.5TiO₄ only one peak is observed which indicates spin glass ordering at 26 K. Furthermore, the A-site canting present in Co₂TiO₄ and CoZnTiO₄ has a collinear and magnetic structure, indicating strong A-B coupling. X-ray analysis indicated that compounds of the system Co₂Zn_xTiO₄ synthesized with cubic symmetry. From transport properties it was found that the activation energy and thermoelectric coefficient decrease with increasing concentration of Zn in the system. The mobility of the system calculated from infrared measurements is typically of the order of 10^–9cm²V^–1s^–1.     

Rheology of polycarbonate/poly(butylene terephthalate) blends containing a core-shell modifier and high-molecular-weight acrylic polymers: Extrusion blow-moldable resins

Several different polymer modifications are currently used to produce commercial plastic materials, especially engineering resins, that have significantly improved melt strength. However, these modifications rarely produce materials that can be formed into very large parts. This study shows that the melt strength of engineering resins can be enhanced by rubber particles having grafted shells that are compatible with the resin. The melt strength of the engineering resin can be further improved by the incorporation of compatible highmolecular-weight polymers. The melt strength improvements thus obtained facilitate the formation of very large parts requiring 8–10 ft long parisons. The effects of shear rate on complex viscosity indicate that the extent of interaction between the polycarbonate matrix and the core-shell impact modifier decreases with increasing shear rate. Therefore, the impact strength of the part molded from a matrix modified with a core-shell rubber may depend on the process history. Dynamic mechanical measurements may provide a means to evaluate the interaction between the matrix and a core-shell modifier in an actual blend. © 1994 John Wiley & Sons, Inc.     

Vesicouterine fistula twenty years following brachytherapy for cervical cancer

Assessment of maternal pelvic dimensions is usually considered necessary where vaginal delivery is contemplated in a breech presentation or if reduced pelvic dimensions are suspected in a current or previous pregnancy. Pelvimetry techniques include computed tomography (CT), conventional radiography, digital fluorography and magnetic resonance imaging (MRI). The first three techniques result in a radiation dose to mother and fetus which, depending on how the technique is performed, can vary by up to 40-fold. Of the techniques using X-rays, CT pelvimetry with a lateral scanogram generally gives the lowest radiation dose and conventional radiography using an air gap technique with a single lateral view is a relatively low-dose alternative where CT is not available. A questionnaire was sent to 227 hospitals during 1993 and 1996 to assess whether there was a move towards lower dose techniques of pelvimetry. The results show a trend away from conventional pelvimetry (48.4% in 1993 to 28% in 1996) with a small proportion of centres using MRI (4%) in 1996. Of the centres still using conventional pelvimetry, relatively few were using a low-dose air-gap technique (2.1% in 1993 to 10.9% in 1996). An increasing majority of centres were using one-view CT (69.3% in 1993 and 80.4% in 1996) but a significant proportion were still performing more than one view. This study shows that there was a move towards lower dose techniques of pelvimetry but that there were still many hospitals that had not implemented a policy of reducing radiation exposure in these patients.     

Lung herniation secondary to minimally invasive direct coronary artery bypass grafting

Lung herniation after thoracotomy is rare. We report a 66-year-old man who presented with this complication after undergoing attempted minimally invasive direct coronary artery bypass grafting. The defect was repaired with a composite of Marlex mesh and methyl methacrylate.     

Psychotherapy and the recovery of memories of childhood sexual abuse: U.S. and British practitioners' opinions, practices, and experiences.

Psychotherapists were surveyed regarding clients' memories of childhood sexual abuse (CSA). The 3 samples were highly similar on the vast majority of measures. Respondents listed a wide variety of behavioral symptoms as potential indicators of CSA, and 71% indicated that they had used various techniques (e.g., hypnosis, interpretation of dreams) to help clients recover suspected memories of CSA . Across samples, 25% of the respondents reported a constellation of beliefs and practices suggestive of a focus on memory recovery, and these psychologists reported relatively high rates of memory recovery in their clients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An Optimal Approach to Online Tuning Method for PID Type Iterative Learning Control

The proportional-integral-derivative (PID) controller is widely used in process control engineering. However, the parameter updating of PID controller has     

Flame synthesis of graphene films in open environments

Few-layer graphene is grown on copper and nickel substrates at high rates using a novel flame synthesis method in open-atmosphere environments. Transmittance and resistance properties of the transferred films are similar to those grown by other methods, but the concentration of oxygen, as assessed by X-ray photoelectron spectroscopy, is actually less than that for graphene grown by chemical vapor deposition under near vacuum conditions. The method involves utilizing a multi-element inverse-diffusion-flame burner, where post-flame species and temperatures are radially-uniform upon deposition at a substrate. Advantages of the specific flame synthesis method are scalability for large-area surface coverage, increased growth rates, high purity and yield, continuous processing, and reduced costs due to efficient use of fuel as both heat source and reagent. Additionally, by adjusting local growth conditions, other carbon nanostructures (i.e. nanotubes) are readily synthesized.     

Removal of ciprofloxacin from aqueous solution using wheat bran as adsorbent

Current study describes sorption of antibiotic drug (ciprofloxacin) by using nontoxic and biocompatible carrier, i.e., wheat bran (WB). For sorption study, various parameters were optimized and Freundlich, Dubinin–Radushkevich, Langmuir, and Temkin isotherm models were applied to demonstrate the mechanism of sorption, while kinetics study for sorption was evaluated using diffusion models, pseudo-first-order kinetic (Langergren) and pseudo-second-order (Ho and McKay) kinetic models. In addition, thermodynamics study was also carried out. However, sorption of ciprofloxacin was pH depended and it showed 75% drug release in alkaline medium (at pH = 1.5) indicating the good release ability of WB for ciprofloxacin.