Influence of Rutile and Anatase TiO2 Nanoparticles on Polyethylene Properties

Nanocomposites from polyethylene and TiO₂ with different shape and size were prepared by direct mixing and masterbatch dilution, respectively. The mechanical properties of nanocomposites were determined and discussed in relation to the nanofiller dispersion. Moreover, the morphological aspects of polyethylene with and without nanofiller were revealed by means of SEM and WAXD. A better dispersion of the nanoparticles and increased mechanical properties were observed in the case of the masterbatch method. No important differences in mechanical and morphological characteristics of anatase and rutile containing polyethylene composites were observed, except a higher increase of the elastic modulus in case of anatase-containing composites.     

Effect of SEBS on morphology, thermal, and mechanical properties of PP/organoclay nanocomposites

A simultaneously increase in stiffness and toughness is needed for improving polypropylene (PP) competitiveness in automotive industry. The aim of this paper is to investigate the effects of styrene-(ethylene-co-butylene)-styrene triblock copolymer (SEBS) on mechanical and thermal properties of PP, in the presence and the absence of nanoclay. The amount of SEBS in PP was ranged to obtain the matrix with the most favorable stiffness–toughness balance. For this purpose, SEBS domain size and distribution in PP/SEBS blends was determined by means of atomic force microscopy and correlated with mechanical properties. The influence of SEBS on the crystalline structure of PP in PP/organoclay nanocomposites was investigated by X-ray diffraction and differential scanning calorimetry, a synergistic effect of SEBS and nanoclay being pointed out. Moreover large improvement in the impact strength (almost 22 times) was obtained in the case of SEBS-containing nanocomposite in comparison with the composite without SEBS.     

Evaluation of a functionalized copolymer as adsorbent on direct dyes removal process: Kinetics and equilibrium studies

Functionalized polymeric microbeads were investigated as adsorbent for the removal of three direct dyes from aqueous solutions. The effects of different experimental parameters, such as initial dye concentration, temperature, and solution pH on the adsorption process were investigated. The adsorption process can be conducted with very good result at normal working conditions: neutral pH and normal temperature. The maximum percentage removal obtained was 99.11% for the symmetrical disazo dye, 90.14% for asymmetrical disazo dye, and 98.53% for trisazo dye. The adsorption kinetics followed the pseudo‐second‐order equation for all three investigated dyes in all working conditions. The experimental data were fitted to Langmuir, Freundlich, Sips, and Redlich–Peterson isotherm models, and the best fit was obtained with Sips model. Thermodynamic parameters (ΔH°, ΔS°, and ΔG°) revealed that dye adsorption is an endothermic and spontaneous process. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

SELECTIVE SEPARATION OF URANYL ION FROM TRU'S IN A COMBINED SOLVENT EXTRACTION PROCESS USING TETRAHYDROFURAN-2,3,4,5-TETRACARBOXYLICACID

ABSTRACT

Selective partitioning of uranyl from transuranic elements in a solvent extraction system which employs a neutral organophosphorus extractant and an aqueous complexant has been demonstrated in a previous report. The extractant solution combines octyl(phenyl)-N,N-diisobutylcarbamoylrnethylphosphine oxide (CMPO), diamyt(amyl)phosphonate (or tributylphosphate), and di(t-butylcyclohexano)-18-crown-6 in Isopar L, and is designed for simultaneous removal of strontium, technetium, lanthanides and actinides from radioactive wastes. The aqueous complexant is tetrahydrofuran-2,3,4,5-tetracarboxylic acid (THFTCA). In this report, the separation of UO₂ ²⁺ from Np(IV), Eu(III), Am(III), and Pu(IV) using the Combined Process Solvent has been optimized. Potentiometric titration and NMR spectroscopic results describe the distribution of THFTCA into the organic phase as a function of acidity and [THFTCA]. Further potentiometric titration experiments have determined the stoichiometry and stability of uranyl complexes in the aqueous phase. The thermodynamic data indicate that the uranyl complexes are anomalously weak which partially accounts for the selectivity. Ternary complexes involving, UO₂ ²⁺ CMPO, and THFTCA in the extractant phase also appear to play a role.     

Atmospheric induced nanoparticles due to the urban street dust

ABSTRACT

Urban street dust (SD) represents a natural source of mineral floating particles (FP) in the atmosphere. The FP particles have usually a wide range of sizes. These particles were monitored and collected by automatic stations in Cluj-Napoca, Romania. The SD and FP samples were investigated by XRD and SEM-EDX analysis. The obtained results prove that both, SD and FP, have a similar composition, namely quartz, clay particles (e.g., muscovite, and kaolinite), calcite, and trace of lepidocrocite. Nanostructural features and fine micro-scaled particles are observed. Quartz and clay nanoparticles were found in SD samples as well as in FP samples. The AFM investigation reveals a nano-size range for quartz particles between 80–90 nm, and 40–60 nm diameter for clay particles. Similar values were obtained by TEM microscopy. The high resolution microscopy results were confirmed by the values obtained by Scherrer formula applied to the XRD patterns. Composition and dimensional similarities found for the nanoparticles in SD and FP samples prove that mineral nanofractions in atmosphere were induced by the urban environmental interactions with the SD. Results provide valuable information on the size, shape, and composition of nanoparticles induced in atmosphere by winds and by environmental interactions with the SD. This work contributes to the evaluation of the air pollution and simultaneously it offers a basis for an improved life quality for Cluj-Napoca population.     

Thermogravimetric analysis of polyurethane–polysulfone blends

Thermal decomposition of blends of a poly(ester urethane) and poly(ether sulfone) with or without poly(urethane sulfone), taken as a compatibilizing agent, was studied by thermogravimetric analysis under dynamic conditions. Theoretical mass loss curves were compared with experimental ones and it was found that the blends studied possessed lower thermal stability than the pure polymers, indicating the presence of interactions in the degradation process. The shifts between the theoretical and experimental curves became smaller as the amounts of polysulfone increased, confirming the thermal stabilisation effect of this polymer. The analysis of activation energy revealed, for both binary and ternary systems, that E_CR (T_max corresponding to the main decomposition stage of polysulfone) increased as the amount of this polymer increased and also the reaction order became zero. For the polyurethane decomposition stages and blending revealed no significant changes as far as activation energy and order of reaction were concerned. © 2002 Society of Chemical Industry     

Energy efficient all-to-all broadcast in all-wireless networks

All-to-all broadcast is a communication pattern in which every node initiates a broadcast. In this paper, we investigate the problem of building a unique cast tree of minimum total energy, which we call Minimum Unique Cast (MUC) tree, to be used for all-to-all broadcast. The MUC tree is unoriented and unrooted. We study three known heuristics for the minimum-energy broadcast problem: the Broadcast Incremental Power (BIP) algorithm, the Wireless Multicast Advantage-conforming Minimum Spanning Tree (WMA-conforming MST) algorithm, and the Iterative Maximum-Branch Minimization (IMBM) algorithm. Experimental results conducted on various types of networks are reported. We show that neither of these methods is best overall for building all-to-all broadcast trees.     

On software verification for sensor nodes

We consider software written for networked, wireless sensor nodes, and specialize software verification techniques for standard C programs in order to locate programming errors in sensor applications before the software's deployment on motes. Ensuring the reliability of sensor applications is challenging: low-level, interrupt-driven code runs without memory protection in dynamic environments. The difficulties lie with (i) being able to automatically extract standard C models out of the particular flavours of embedded C used in sensor programming solutions, and (ii) decreasing the resulting program's state space to a degree that allows practical verification times.We contribute a platform-dependent, OS-independent software verification tool for OS-wide programs written in MSP430 embedded C with asynchronous hardware interrupts. Our tool automatically translates the program into standard C by modelling the MCU's memory map and direct memory access. To emulate the existence of hardware interrupts, calls to hardware interrupt handlers are added, and their occurrence is minimized with a double strategy: a partial-order reduction technique, and a supplementary reachability check to reduce overapproximation. This decreases the program's state space, while preserving program semantics. Safety specifications are written as C assertions embedded in the code. The resulting sequential program is then passed to CBMC, a bounded software verifier for sequential ANSI C. Besides standard errors (e.g., out-of-bounds arrays, null-pointer dereferences), this tool chain is able to verify application-specific assertions, including low-level assertions upon the state of the registers and peripherals.Verification for wireless sensor network applications is an emerging field of research; thus, as a final note, we survey current research on the topic.     

DE-BAR: Device Energy-Centric Backlight and Adaptive Region of Interest Mechanism for Wireless Mobile Devices

One of the main challenges in the smart-phone world is that they are battery constrained and the development of battery technologies have not kept pace with the required energy demand. In particular, there are still significant technological gaps on developing energy-aware solutions that would prolong the battery life of devices without affecting the quality of the distributed video/multimedia content. In this aspect, this paper proposes DE-BAR—a process based innovation that will provide a seamless battery saving mechanism, based on backlight and adaptive region of interest of the streamed multimedia content. This work intends to look at the nature of the video/multimedia content that is received in the device and adapts the energy consumption dynamically at three levels: Screen Colour, backlight and Intensity; and adaptive Region-of-Interest (RoI) based variation in the multimedia content. Notably, the work provides the mechanism for real-time adaptation. The colour intensity, number of RoI for the video sequence and the frame rate is decided by the spatial and temporal complexity of the video. The energy consumption is measured using an Arduino board while video quality is analyzed using extensive subjective tests. The results indicate that more than 50% energy could be saved in the device while retaining above average perceptual video quality.