Strength improvements in toughened epoxy composites using surface treated GnPs

Nanographitic materials are gaining enormous interest as a new class of reinforcement for nanocomposites, promising revolutionary electrical, thermal, and mechanical properties. However, the progress has been quite limited especially in terms of mechanical properties. Here we report a significant leap, >2× increases in tensile strength and modulus of an epoxy composite using surface treated graphite nanoplatelets (GnPs). This corroborated by increases in Tgs as well as the presence of oxygen‐functionalized groups verified by XPS, suggest improved distribution and chemical interaction at the filler‐to‐matrix interface. Toughness values also showed increases with concentration, without compromising the strength or failure strain. However, if solvent levels during degassing were not reduced sufficiently, negligible contributions to strength and stiffness were observed with GnP loading. Subsequent elevated temperature treatments increased the strength of the composite due to cure enhancement of the matrix material, yet did not provide mechanical enhancements due to the incorporation of the filler. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40802.     

Movement abnormalities and the progression of prodromal symptomatology in adolescents at risk for psychotic disorders.

The link between movement abnormalities and psychotic disorders is presumed to reflect common neural mechanisms that influence both motor functions and vulnerability to psychosis. The prodromal period leading to psychotic disorders represents both a viable point for intervention and a developmental period that, if studied, could shed light on etiology; however, no published studies have examined the temporal progression of this link. A group with high levels of prodromal symptomatology (i.e., adolescents with schizotypal personality disorder [SPD]; n = 42) and both psychiatric controls (with other personality disorders or conduct disorder [OD]; n = 30) and nonpsychiatric controls ([NC]; n = 49) were recruited. Videotapes of structured psychiatric interviews were coded for movement abnormalities by raters blind to participants' diagnostic status, and follow-up assessments were conducted 1 year later. Controlling for psychotropic medications, the authors found that adolescents with SPD exhibited significantly more motor abnormalities in the face and upper body than did OD and NC controls. At baseline, movement abnormalities were positively correlated with the severity of positive, negative, and total prodromal symptoms. Within the SPD group, baseline movement abnormalities predicted symptom severity 1 year later. Movement abnormalities represent an early risk indicator that may be predictive of later symptom severity and potentially of psychosis onset. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantitation of Hydrochlorothiazide in Combination with Methyldopa and Propranolol Hydrochloride by High-Performance Liquid Chromatography

A stability indicating assay method based on highperformance liquid chromatography has been developed for the quantitation of hydrochlorothiazide in combination with methyldopa and propranolol hydrochloride. The method is accurate, reproducible and precise with an average percent relative standard deviation of 1.3. The method can also be used for the quantitation of the only known impurity/decomposition product (4-amino, 6 chloro, 1,3 benzenedisulfonamide) in hydrochlorothiazide. For the complete separation of methyldopa from hydrochlorothiazide, a counterion, 1-heptanesulfonic acid sodium was added to the mobile phase to increase the retention time of methyldopa. A 4-5 minutes time to extract hydrochlorothiazide from tablets appears to be satisfactory.     

Tailoring of Electromagnetic Absorption in Substituted Hexaferrites from 8.2 GHz to 12.4 GHz

Journal of Electronic Materials - Microwave absorbers are an important topic of interest to mitigate electromagnetic interference. Here, we have investigated electromagnetic absorption properties...     

Toward the Understanding of CoAl2O4 Additions on the Formation of Microstructure in Alloy 718 Processed by Laser Powder Bed Fusion

Metallurgical and Materials Transactions A - This investigation rationalizes the impact of oxide particles on the melt pool and subsequent formation of microstructure in superalloy Inconel 718...     

Systematic generation of alternative production schedules

We propose a systematic approach for generating alternative production schedules to address two challenges in implementing optimization-based scheduling techniques in industrial settings: (a) the limited scope of the scheduling models due to modeling simplifications, and (b) the consideration of shop-floor nervousness. We first introduce metrics to quantify specific characteristics of a schedule (e.g., number of batches and degree of nervousness). Next, we favor, at different degrees, such characteristics in each alternative schedule, by penalizing the metrics in the objective function. Through illustrative instances, we show that multiple alternative schedules, including schedules with desired properties can readily be generated.     

Seeker: A bandwidth-based association control framework for wireless mesh networks

The rapid deployment of wireless mesh networks across universities and enterprises, and the pervasiveness of mobile devices equipped with Wi-Fi connectivity, has resulted in a scenario wherein end users have the option to choose from a multitude of access points at any given location. Moreover, with the increasing availability of rich online content, there has been a steady increase in mobile Internet traffic. Since the choice of access point that a user associates with will directly impact his performance, it is imperative that there exist an efficient association control mechanism, in order to enhance the end user’s experience. As part of this work, we propose Seeker, a novel framework for association control in wireless networks that utilizes “available bandwidth” as the design metric. The goal of Seeker is to assist the mesh network in making an intelligent decision regarding which access point a client should associate with. As part of our scheme, we implement and evaluate a passive tool to estimate available bandwidth in wireless networks. We then describe how we use this tool to implement our association control scheme, and evaluate it via extensive experiments on an outdoor testbed. Seeker takes into consideration the performance of the mesh backhaul, in addition to the client-to-AP link quality, thereby achieving significant advantages over traditional association control schemes for wireless-LANs.     

Study of the conditions for multi‐modal chromatographic capture of Fab′ from dual‐salt precipitated E. coli homogenate

BACKGROUND: In the commercial‐scale purification of immunotherapeutics, Protein A chromatography is employed routinely for its high binding capacity and selectivity. Nevertheless, matrix cost and ligand leaching issues remain and there are many alternatives such as ion‐exchange and multi‐modal resins that are less expensive. However, binding capacities are lower than Protein A owing to the co‐adsorption of protein impurities. One solution involves removing impurities before chromatography by precipitation and a potential approach presented in the literature recently employs a dual‐salt precipitation technique. The current study explores the impact of this upon the capture of an antibody fragment by a multimodal cation exchange resin. RESULTS: The dual salt precipitation procedure employed here removed 36% of the contaminant proteins. A microscale chromatography pipette tip approach was used in a high throughput screening format to scout rapidly for favourable binding conditions successfully. Higher binding capacities were achieved by activating the hydrophobic binding modality of the resin at feed ionic strengths of around 150 mS cm^?1 using ammonium sulphate. This was better than using the ion‐exchange modality at below 10 mS cm^?1. CONCLUSIONS: Dual salt precipitation followed by chromatographic capture using this resin were found to be complementary to one another since the removal of protein impurities by dual salt precipitation resulted in a two‐fold improvement in terms of binding capacity. © 2012 Society of Chemical Industry     

Development and gamma scintigraphy evaluation of gastro retentive calcium ion-based oral formulation: an innovative approach for the management of gastro-esophageal reflux disease (GERD)

Calcium chloride is an essential calcium channel agonist which plays an important role in the contraction of muscles by triggering calcium channel. First time hypothesized about its role in the treatment of GER (gastro-esophageal reflux) and vomiting disorder due to its local action. There are two objectives covered in this study as first, the development and optimization of floating formulation of calcium chloride and another objective was to evaluate optimized formulation through gamma scintigraphy in human subjects. Gastro retentive formulation of calcium chloride was prepared by direct compression method. Thirteen tablet formulations were designed with the help of sodium chloride, HPMC-K4M, and carbopol-934 along with effervescing agent sodium bicarbonate and citric acid. Formulation (F8) fitted best for Korsmeyer–Peppas equation with an R² value of 0.993. The optimized formulation was radiolabelled with ^99mTc-99?m pertechnetate for its evaluation by gamma scintigraphy. Gastric retention (6?h) was evaluated by gamma scintigraphy in healthy human subjects and efficacy of present formulation confirmed in GER positive human subjects. Gamma scintigraphy results indicated its usefulness in order to manage GERD. Stability studies of the developed formulation were carried out as per ICH guidelines for region IV and found out to be stable for 24?months.