Development of a High-Strength Ultrafine-Grained Ferritic Steel Nanocomposite

This article describes the microstructural and mechanical properties of 12YWT oxide-dispersion-strengthened (ODS)-ferritic steel nanocomposite. According to the annealing results obtained from X-ray diffraction line profile analysis on mechanically alloyed powders milled for 80 hours, the hot extrusion at 1123 K (850 °C) resulted in a nearly equiaxed ultrafine structure with an ultimate tensile strength of 1470 MPa, yield strength of 1390 MPa, and total elongation of 13 pct at room temperature comparable with high-strength 14YWT ODS steel. Maximum total elongation was found at 973 K (600 °C) where fractography of the tensile specimen showed a fully ductile dimple feature compared with the splitting cracks and very fine dimpled structure observed at room temperature. The presence of very small particles on the wall of dimples at 1073 K (800 °C) with nearly chemical composition of the matrix alloy was attributed to the activation of the boundaries decohesion mechanism as a result of diffusion of solute atoms. The results of Charpy impact test also indicated significant improvement of transition temperature with respect to predecessor 12YWT because of the decreased grain size and more homogeneity of grain size distribution. Hence, this alloy represented a good compromise between the strength and Charpy impact properties.     

Increased Postprandial Triglyceride-Rich Lipoprotein Levels in Elderly Survivors of Myocardial Infarction

Postprandial triglyceride-rich lipoproteins (TRL) levels are a predictor for coronary atherosclerosis. The aim of the study was to compare fasting high density lipoprotein (HDL) cholesterol, plasma lipoprotein lipase (LPL) activity, and postprandial TRL between elderly survivors of myocardial infarction (MI) and healthy controls. A case-control study was performed in 44 elderly patients 65-85 years of age with a previous history of MI and 43 age- and sex-matched healthy controls. Each participant underwent physical examination and was given a standard oral fat load with subsequent blood sampling over the next 8 h. Total and chylomicron triglycerides were assessed by area under the curve (AUC), incremental are under the curve (AUCi) and triglyceride response (TGR). Elderly MI patients had significantly lower postheparin LPL activity (87.4 +/- 36.9 mU/ml) (mean +/- 1 SD) than healthy controls (106.0 +/- 29.0 mU/ml) (P = 0.014). Decreased postheparin LPL activity was accompanied by significant increased and delayed clearance of postprandial TRL. Fasting HDL cholesterol was significantly lower in elderly MI patients than controls (1.45 +/- 0.32 and 1.66 +/- 0.47 mmol/l, respectively, P = 0.048). Multiple regression analysis revealed postheparin LPL activity as an independent predictor for postprandial TRL and fasting HDL cholesterol. Logistic regressions analysis revealed HDL cholesterol, triglycerides measured 2 h after the oral fat load, and postheparin LPL activity as independent predictors for MI. Our findings indicate that decreased fasting HDL cholesterol is associated with increased postprandial triglyceridemia which could be a target for life-style and therapeutic interventions in patients at risk for cardiovascular disease.     

Dispersion of chiral amino acid organomodified Cloisite Na in poly(vinyl alcohol) matrix for designing of novel bionanocomposite films

In this study the inorganic nanolayers of Cloisite Na⁺ was modified with ammonium salt of l-valine amino acid (Val) and then it was dispersed in poly(vinyl alcohol) (PVA) matrix. The PVA/Cloisite Na⁺/Val bionanocomposites (BNC)s were prepared by solution intercalation technique using ultrasonic irradiation. The reaction between this novel organically modified Cloisite Na⁺ and PVA occurred by the hydrogen bonding and hydrophobic interactions. The basal spacing of the Cloisite Na⁺/Val was studied by X-ray diffraction. The thermal stability and optical clarity of PVA and PVA/Cloisite Na⁺/Val are also studied by thermogravimetric analysis (TGA) and UV–visible transmission spectra, respectively. TGA results show that using Cloisite Na⁺/Val in the PVA matrix improved the thermal stability property of the resulting BNC films. The morphological image of synthesized materials was studied by scanning electron microscopy, and transmission electron microscopy. The nanocomposite structure study specified a coexistence of exfoliated and intercalated Cloisite Na⁺/Val layers in the PVA matrix.     

Enhancement of mechanical and thermal properties of polycaprolactone/chitosan blend by calcium carbonate nanoparticles

This study investigates the effects of calcium carbonate (CaCO(3)) nanoparticles on the mechanical and thermal properties and surface morphology of polycaprolactone (PCL)/chitosan nanocomposites. The nanocomposites of PCL/chitosan/CaCO(3) were prepared using a melt blending technique. Transmission electron microscopy (TEM) results indicate the average size of nanoparticles to be approximately 62 nm. Tensile measurement results show an increase in the tensile modulus with CaCO(3) nanoparticle loading. Tensile strength and elongation at break show gradual improvement with the addition of up to 1 wt% of nano-sized CaCO(3). Decreasing performance of these properties is observed for loading of more than 1 wt% of nano-sized CaCO(3). The thermal stability was best enhanced at 1 wt% of CaCO(3) nanoparticle loading. The fractured surface morphology of the PCL/chitosan blend becomes more stretched and homogeneous in PCL/chitosan/CaCO(3) nanocomposite. TEM micrograph displays good dispersion of CaCO(3) at lower nanoparticle loading within the matrix.     

Emulsion polymerization of styrene: Simulation the effects of mixed ionic and non-ionic surfactant system in the presence of coagulation

A detailed model was developed for emulsion polymerization of styrene in batch reactor to predict the evolution of the product particle size distribution. The effect of binary surfactant systems (ionic/non-ionic surfactants) with different compositions was studied. The zero–one kinetics was employed for the nucleation rate, with the model comprising a set of rigorously developed population balance equations. The modeling incorporated particle formation by both nucleation and coagulation phenomena. The partial differential equations describing the particle population were discretized using finite volume elements. Binary surfactant systems, comprising sodium dodecyl sulfate (SDS) as anionic, and a commercial polyether polyol (Brij35^®) as non-ionic surfactants, were examined with different mass ratios. Increasing non-ionic surfactant mass fraction in binary surfactant system showed the decrease of particle number due to intensifying the coagulation between particles. Broader particle size distributions with greater average particle size were obtained with non-ionic surfactant comparing those obtained with anionic one.     

Synthesis of polyelectrolyte-modified ordered nanoporous carbon for removal of aromatic organic acids from purified terephthalic acid wastewater

In this work polyelectrolyte (polydiallyldimethylammonium chloride) modified ordered mesoporous carbon (CMK-1/PDDA) has been synthesized and has been employed in removal of major aromatic compounds present in purified terephthalic acid wastewater, such as p-toluic acid, benzoic acid, 4-carboxybenzaldehyde, phthalic acid and terephthalic. The adsorption behavior of these acidic impurities has been studied through batch experiments and using UV-spectrophotometric technique. The results show that CMK-1/PDDA is very effective in selective removal of acidic compounds from PTA-waste aqueous solutions. The electrostatic interaction was considered to be the main mechanism for the adsorption of acidic compounds. The effects of chemical modification, contact time, initial concentrations, adsorbent dose, agitation speed, solution pH and reaction temperature have been optimized. The sorption equilibrium was reached within 5 min. The sorption of acidic compounds on the CMK-1/PDDA slightly decreases with increasing pH, and temperature, indicating an exothermic process. The experimental isotherm data were analyzed using the Langmuir and Freundlich equations. The equilibrium data were best represented by the Langmuir isotherm.     

Outdoor scene image segmentation based on background recognition and perceptual organization

In this paper, we propose a novel outdoor scene image segmentation algorithm based on background recognition and perceptual organization. We recognize the background objects such as the sky, the ground, and vegetation based on the color and texture information. For the structurally challenging objects, which usually consist of multiple constituent parts, we developed a perceptual organization model that can capture the nonaccidental structural relationships among the constituent parts of the structured objects and, hence, group them together accordingly without depending on a priori knowledge of the specific objects. Our experimental results show that our proposed method outperformed two state-of-the-art image segmentation approaches on two challenging outdoor databases (Gould data set and Berkeley segmentation data set) and achieved accurate segmentation quality on various outdoor natural scene environments.     

An infobutton for Web 2.0 clinical discussions: the knowledge linkage framework

This paper aims to develop an infobutton to automatically retrieve published papers corresponding to a topic-specific online clinical discussion. The knowledge linkages infobutton is designed to supplement online clinical conversations with pertinent medical literature from Pubmed. The project involves three distinct steps: 1) Clinical messages around a specific problem are grouped together into a thread. 2) These threads are processed using Metamap to link the conversations to keywords from the MeSH lexicon. 3) These keywords are used in a novel search strategy to retrieve a set of papers from Pubmed, which are then returned to the user. A pilot study using the messages from 2007 and 2008, was conducted to compare the knowledge linkage search strategy to a vector space model and extended Boolean model. The knowledge linkage model proved to be significantly better in terms of precision ( p = 0.013 and 0.003, respectively) and recall ( p = 0.351 and 0.013). Pertinent papers were returned to over 55% of the threads. This approach has demonstrated how clinicians can supplement their peer communications with evidence based research. Future work should focus on how to improve the threading and keyword-mapping strategies.     

Evaluation of Antioxidant Compounds and Total Sugar Content in a Nectarine [Prunus persica (L.) Batsch] Progeny

Epidemiological studies suggest that consumption of fruit rich in phenolic compounds is associated with health-protective effects due to their antioxidant properties. For these reasons quality evaluation has become an important issue in fruit industry and in breeding programs. Phytochemical traits such as total phenolics, flavonoids, anthocyanins, L-ascorbic acid, sugar content and relative antioxidant capacity (RAC) were analyzed over four years in flesh fruit of an F1 population "Venus" × "Big Top" nectarines. Other traits such as harvesting date, yield, fruit weight, firmness, soluble solids concentration (SSC), pH, titratable acidity (TA) and ripening index (RI) were also determined in the progeny. Results showed high variability among genotypes for all analyzed traits. Total phenolics and flavonoids showed significant positive correlations with RAC implying that both are important antioxidant bioactive compounds in peaches. We found genotypes with enhanced antioxidant capacity and a better performance than progenitors, and in consequence the best marketability.     

Pretreatment of wool/polyester blended fabrics to enhance titanium dioxide nanoparticle adsorption and self‐cleaning properties

This research aims to enhance the self‐cleaning properties of fibre‐blended fabric using surface pretreatment prior to the application of titanium dioxide nanoparticles. To this end, the polyester/wool fabric was modified, in that the wool fibres were oxidised with potassium permanganate and the polyester fibres were hydrolysed with lipase before nano processing. Butane tetracarboxylic acid was also used to enhance the adsorption of the nanoparticles and also to stabilise them on the fabric surface. The self‐cleaning properties of the fabric were examined through staining of the fabric with CI Basic Blue 9 and then discolouring by exposing to ultraviolet and daylight irradiation. Some other properties of the treated fabrics, such as water drop absorption, crease recovery angle and bending were investigated and are discussed in detail. The colour changes of different samples indicated an appropriate discoloration on the titanium dioxide‐treated fabrics after ultraviolet and daylight irradiation. Overall, the surface pretreatment of the wool and polyester fibres improved the self‐cleaning properties of the fabric significantly.