Graphene quantum dots derived from carbon fibers

Graphene quantum dots (GQDs), which are edge-bound nanometer-size graphene pieces, have fascinating optical and electronic properties. These have been synthesized either by nanolithography or from starting materials such as graphene oxide (GO) by the chemical breakdown of their extended planar structure, both of which are multistep tedious processes. Here, we report that during the acid treatment and chemical exfoliation of traditional pitch-based carbon fibers, that are both cheap and commercially available, the stacked graphitic submicrometer domains of the fibers are easily broken down, leading to the creation of GQDs with different size distribution in scalable amounts. The as-produced GQDs, in the size range of 1-4 nm, show two-dimensional morphology, most of which present zigzag edge structure, and are 1-3 atomic layers thick. The photoluminescence of the GQDs can be tailored through varying the size of the GQDs by changing process parameters. Due to the luminescence stability, nanosecond lifetime, biocompatibility, low toxicity, and high water solubility, these GQDs are demonstrated to be excellent probes for high contrast bioimaging and biosensing applications.     

Flow properties of vacuum gas oil–low density polyethylene blends

In this paper, the viscous flow behaviour of Vacuum Gas Oil (VGO) with different fractions (0–10% wt.) of Low Density Polyethylene (LDPE) under dynamic shear has been investigated. Viscosimetry measurements of the blends at temperatures between 333 and 433 K using a BOHLIN Controlled Stress Rheometer, as well as compatibility studies using Differential Scanning Calorimetry (DSC) were carried out. The effects of the variation of the blends polymer content on the activation energy of flow has also been investigated. The results obtained reveal that the blends show Newtonian flow behaviour at higher temperatures for all polymer concentrations studied, while at lower temperatures and at higher polymer concentrations, they show non-Newtonian shear-thinning behaviour. Furthermore, at lower temperatures, these behaviours are more pronounced at lower shear rates than at higher shear rates. As the polymer content in the blend is increased, the shear viscosity increases, the flow behaviour index decreases, and the application of an Arrhenius type equation shows an increase in the activation energy of flow at the lower shear rates.     

KEPPAN: Knowledge exploitation for proactively-planned ad-hoc networks

This paper explores the idea of managing mobile ad-hoc networks (MANETs) by the communication needs of their nodes, as a means to facilitate the operation of distributed applications. Specifically, we present a middleware layer that enables reasoning about the multiple possibilities there may exist to ensure satisfiability of certain communication needs. This middleware has been explicitly devised to handle partial and changeable knowledge about the networks, and to guide the search for missing information whenever it cannot conclude whether it will be possible to satisfy some needs. These features provide the basis to implement policies with which to coordinate activities in a MANET, in quest for the configuration that best satisfies the communication needs of its nodes. We provide simulation results to show the comparative advantages of our solution, plus a report of experiments to assess its practicality and usability.     

ATLAS: a framework to provide multiuser and distributed t‐learning services over MHP

The increasing need of the developed countries to carry out effective distance learning strategies has led to a great development of Internet‐based learning technologies (e‐learning). Despite its evident advantages, the expansion of e‐learning has been limited by the difficulty in reaching important social sectors, and also by the absence of mechanisms to fight the feeling of isolation of the users, which often leads them to abandoning the distance learning activities. This paper tackles these problems by introducing ATLAS, a framework for the development and deployment of multiuser t‐learning services (i.e. learning services over Interactive Digital TV). This framework is built around three major features: an architecture for the services that exploits the multimedia capabilities of the television, a communications infrastructure that promotes the establishment of virtual learning communities, and a development tool that allows services to be created with minimum programming knowledge. ATLAS has been designed by considering several features that make Interactive Digital TV quite different from the PC, advising against the direct translation of the models developed for the Internet. In particular, ATLAS adheres to the Multimedia Home Platform (MHP) standard, which is gaining worldwide acceptance as one of the technical solutions that will shape the future of Interactive Digital TV. Copyright © 2006 John Wiley & Sons, Ltd.     

Contribution of low‐molecular‐weight antioxidants to the antioxidant capacity of raw and processed lentil seeds

In this study four cultivars of lentil originating from Spain were examined: cv Paula, cv Agueda, cv Almar and cv Alcor. Since consumption of these seeds after heat treatment and as sprouts has been popularised, the impact of cooking (up to 30 min) and germination process (in dark, at 25°C, for up to 4 days) on peroxyl radical‐trapping capacity (PRTC) and Trolox‐equivalent antioxidant capacity (TEAC) of the processed seeds was addressed. Also, changes in the content of low‐molecular‐weight antioxidants (LMWA) and soluble proteins in the course of cooking and germination were studied. The analyzed LMWA were: total phenolics, tocopherols (α‐T, β‐T, γ‐T, δ‐T( reduced glutathione, and L ‐ascorbic acid. On the basis of the results obtained, the contribution of LMWA and soluble proteins to the PRTC and TEAC of raw, cooked, and germinated lentil seeds was calculated by multiple mean values for the content of investigated compounds and their relative potential with respect to Trolox. The results showed a very high molar percentage contribution of phenolic compounds and low contribution of tocopherols, glutathione, soluble proteins, and ascorbate (only in germinated seeds) to the total TEAC and total PRTC calculated as a sum of data provided for phosphate‐buffered and 80% methanolic extracts of raw and processed lentil seeds.     

Differential scanning calorimetry of mixtures of EVA and PE. Kinetic modeling

Mixtures of commercial EVA and different concentration of PE have been prepared and the heat evolution during two successive heating experiments has been studied by means of differential scanning calorimetry (DSC). A kinetic model has been suggested and applied, involving the different intrinsic fractions susceptible of undergoing transitions during the experiment, and also the concentration of PE in the initial binary mixture. Moreover, the variation of the apparent heat capacities of the different fractions and components with the temperature has been considered, yielding a remarkable improvement in the fitting of the DSC curves in the whole range of temperature studied. The models applied are capable of representing all the different processes observed and can be of great interest in the understanding of such phenomena, as well as in modeling the heat involved in the industrial processing of these types of products.     

Chemometric study on the forensic discrimination of soil types using their infrared spectral characteristics

Soil has been utilized in criminal investigations for some time because of its prevalence and transferability. It is usually the physical characteristics that are studied; however, the research carried out here aims to make use of the chemical profile of soil samples. The research we are presenting in this work used sieved (2 mm) soil samples taken from the top soil layer (about 10 cm) that were then analyzed using mid-infrared spectroscopy. The spectra obtained were pretreated and then input into two chemometric classification tools: nonlinear iterative partial least squares followed by linear discriminant analysis (NIPALS-LDA) and partial least squares discriminant analysis (PLS-DA). The models produced show that it is possible to discriminate between soil samples from different land use types and both approaches are comparable in performance. NIPALS-LDA performs much better than PLS-DA in classifying samples to location.     

Socioeconomic disparities in pain: The role of economic hardship and daily financial worry.

Objective: Socioeconomic disparities in pain may be attributable to both greater frequency in stressful financial events as well as greater vulnerability to economic hardship for those at the lower end of the socioeconomic spectrum. This study investigated the effects of economic hardship and daily financial worry on daily pain among women with a chronic musculoskeletal condition. Design: The sample consisted of 250 women with osteoarthritis (N = 105), fibromyalgia (N = 46), or both (N = 99). During an initial assessment, participants' chronic pain diagnosis, level of economic hardship, and demographic information were ascertained. For a period of 30 days, daily diary assessments recorded daily financial worries and daily pain severity. Hypotheses were tested using multilevel modeling for repeated measures in SAS PROC MIXED. Main Outcome Measure: Daily pain severity. Results: Conditions of economic hardship and daily ratings of financial worry both had significant detrimental effects on daily pain. Participants with greater levels of economic hardship reported greater pain severity in response to daily financial worries than their counterparts with little or no economic hardship. Further, participants in the sample who were not employed and who reported higher levels of economic hardship exhibited the most pain reactivity in response to daily financial worries. Conclusion: Economic hardship was associated not only with greater exposure to daily financial worries but also with greater vulnerability to pain on days when daily financial worries were experienced. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

DSC study of foamable poly (vinyl chloride‐co‐vinyl acetate) plastisols of different commercial plasticizers

In this article the characterization of the thermal behavior of foamable PVC (Poly (vinyl chloride)) plastisols from 20 different plasticizers has been studied by differential scanning calorimetry (DSC). The interactions between the resin and the plasticizer as well as the decomposition of the azodicarbonamide (ADC)—the chemical blowing agent (CBA) used—have been analyzed. The latter process is of crucial importance for the knowledge of plasticized PVC flexible foam formation. Clear effects of the chemical nature of the plasticizers and their molecular weight (M_w) have been observed, both in the interactions (swelling and early stages of gelation) between the resin and the plasticizer, as well as in the temperature of the ADC decomposition and the shape of the DSC peak. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Contribution of low-molecular-weight antioxidants to the antioxidant capacity of raw and processed lentil seeds

In this study four cultivars of lentil originating from Spain were examined: cv Paula, cv Agueda, cv Almar and cv Alcor. Since consumption of these seeds after heat treatment and as sprouts has been popularised, the impact of cooking (up to 30 min) and germination process (in dark, at 25 degrees C, for up to 4 days) on peroxyl radical-trapping capacity (PRTC) and Trolox-equivalent antioxidant capacity (TEAC) of the processed seeds was addressed. Also, changes in the content of low-molecular-weight antioxidants (LMWA) and soluble proteins in the course of cooking and germination were studied. The analyzed LMWAwere: total phenolics, tocopherols (alpha-T, beta-T, gamma-T, delta-T), reduced glutathione, and L-ascorbic acid. On the basis of the results obtained, the contribution of LMWA and soluble proteins to the PRTC and TEAC of raw, cooked, and germinated lentil seeds was calculated by multiple mean values for the content of investigated compounds and their relative potential with respect to Trolox. The results showed avery high molar percentage contribution of phenolic compounds and low contribution of tocopherols, glutathione, soluble proteins, and ascorbate (only in germinated seeds) to the total TEAC and total PRTC calculated as a sum of data provided for phosphate-buffered and 80% methanolic extracts of raw and processed lentil seeds.