Agro-Waste Generated Pd/CAP-Ash Catalyzed Ligand-Free Approach for Suzuki–Miyaura Coupling Reaction

Catalysis Letters - We converted agro-waste Custard Apple Peels (CAP) to ash via thermal treatment, on which Pd(OAc)2 was immobilized easily that produced a low-cost, highly efficient Pd/CAP-ash...     

Reusable and Efficient Polystyrene Immobilized Ionic Liquid Catalyst for Batch and Flow Methylation of Hydroquinone

Catalysis Letters - An environmentally benign process for synthesizing 4-methoxyphenol through methylation of hydroquinone using polystyrene immobilized Bronsted acidic ionic liquid is presented....     

Effect of nBaCO3 on mechanical,thermal and morphological properties of isotactic PP-EPDM blend

Isotactic polypropylene (iPP): ethylene propylene diene monomer (EPDM) blend is one of the most suited compatible and miscible blends. The blends of iPP and EPDM (80:20) filled with BaCO₃ nanoparticles (0.5, 1.5, 2.5 and 3 wt%) were prepared on Brabender Plasticorder, which was then subjected to injection molding to get dumbbell-shaped specimens. Meanwhile, BaCO₃ nanoparticles (nBaCO₃) were prepared using ultrasonic cavitation technique. The size and shape of nBaCO₃ particle was confirmed using transmission electron microscope and found to be capsule shape of diameter ~40–60 nm with aspect ratio (l/d) of 2.2–2.5. The reduction in particle size of nBaCO₃ leads to formation of uniform suspension. The solution was kept as such for long time so as to nullify the charges developed over the surface of nanoparticles. The mechanical properties of nBaCO₃-reinforced iPP-EPDM blends were studied using universal testing machine and impact tester. Moreover, thermal properties were studied using flammability tester, vicat softening temperature, thermo gravimetric analyzer and differential scanning calorimeter (DSC). Dispersion of nBaCO₃ in iPP-EPDM matrix was studied using scanning electron microscope and X-ray diffractometer. The mechanical and thermal properties of iPP-EPDM/nBaCO₃ blends were found to be improved significantly with increasing amount of nBaCO₃ up to 2.5 wt%, which is due to good compatibility in between iPP and EPDM with uniform dispersion of nBaCO₃. Moreover, due to agglomeration at 3 wt% loading of nBaCO₃ few of the properties found to be decreased marginally.     

Simultaneous Enhancement of Fracture Toughness and Unipolar Strain in Pb(Zr,Ti)O3‐ZrO2 Composites Through Composition Adjustment

The influence of second phase zirconia particles on the electrical properties and fracture behavior of various polycrystalline soft Pb(Zr_1?xTi_x)O₃ (PZT) compositions was investigated. PZT composites with yttria‐stabilized tetragonal zirconia particles exhibited enhanced crack resistance in comparison to monolithic compositions, regardless of the PZT composition. The addition of zirconia, however, was found to change the PZT composition through the diffusion of zirconium, resulting in variations in the observed piezoelectric and ferroelectric responses. Through the tailoring of the PZT matrix composition, the large electromechanical response and enhanced fracture toughness could be retained. The variation in both small and large signal properties is contrasted to fracture results and crystal structure changes, as determined by X‐ray diffraction.     

Distributed topology management for wireless multimedia sensor networks: exploiting connectivity and cooperation

In this paper, we propose a distributed topology management algorithm, named T‐Must, which orchestrates coalition formation game between camera and scalar sensor (SS) nodes, for use in wireless multimedia sensor networks. In the proposed solution, connectivity among the peer camera sensor (CS) nodes is maintained, and coverage is ensured between them. Only the scalar data are not sufficient to describe an event in a particular monitored area. In many cases, multimedia data (specifically, video data) are required to provide more precise information about the event. As the CS nodes, which sense and transmit multimedia data, are costlier than the SS nodes, the former are deployed in the monitored area in lesser numbers compared to the latter ones. In case of CS nodes, power consumption due to sensing is also significant, similar to power consumption for the transmission and reception of packets. Therefore, in this work, in order to increase the network lifetime, topology is controlled by forming coalition between the CS and SS nodes. Upon occurrence of an event, the SS nodes send scalar data to their associated CS nodes. If the scalar data received from SS nodes cross a preconfigured threshold, the associated CS node in the coalition starts sensing the event, captures the video data, and forwards the video data toward other coalitions or sink. Copyright © 2014 John Wiley & Sons, Ltd.     

平均波长和输出功率稳定性高的掺铒光子晶体光纤超荧光光源的实验研究

采用掺铒光子晶体光纤代替传统掺铒光纤来提高超荧光光纤光源输出的功率稳定性和平均波长稳定性。在-45℃~70℃的全温区范围内,对超荧光光纤光源的光纤长度和半导体激光器(LD)抽运功率进行优化,并提出了用插值法进行LD抽运功率的优化方法,在光纤长度优化的基础上,高效、精确地优化了抽运功率,改善了光源的平均波长稳定性。经过优化的光源,在-45℃~70℃的全温区范围内平均波长变化量为0.67×10-6/℃,输出功率稳定性为0.37%。     

Scientific collaboration of researchers and organizations: a two-level blockmodeling approach

Scientometrics - The development and successful implementation of R&D policies depends on understanding patterns of scientific collaboration (SC). Existing studies on SC typically focus on...     

Transient and steady states of Gd2Zr2O7 and 2ZrO2∙Y2O3 (ss) interactions with calcium magnesium aluminium silicates

Reactions between calcium magnesium aluminium silicates (CMAS) and Gd₂Zr₂O₇ or 2ZrO₂?Y₂O₃ (ss) are investigated within a temperature range of 1200–1300 °C and for durations of 1 h–100 h. The evolution of CMAS penetration depth in Gd₂Zr₂O₇ and 2ZrO₂?Y₂O₃ (ss) pellets varies considerably depending on the interaction time. A quantitative analysis of the nature and composition of phases observed in stationary conditions (powder/powder interaction) is performed by SEM-FEG coupled with WDS analyses using micro-agglomerated nanoparticles of Gd₂Zr₂O₇ and 2ZrO₂?Y₂O₃. Faster kinetics of the gadolinium-based system are illustrated through an analysis of the morphology of the reaction area and of the resulting CMAS tightness of reaction products. The compositions and quantities of reaction products observed at equilibrium are very similar for the two systems, but transient states are significantly different.     

Determination of the Exciton Binding Energy Using Photothermal and Photoluminescence Spectroscopy

In this paper, experimental photoluminescence (PL) and piezoelectric photothermal (PPT) spectra of selected II–VI binary crystals are presented and analyzed. The quantitative analysis of the photothermal spectra was performed using a modified and extended Jackson–Amer model. The values of the bandgap energies of investigated semiconductors were computed from the PT amplitude and phase spectra. From the temperature dependence of the exciton emission so-called “excitonic energy gaps” have been determined. It follows from the theory that the exciton binding energy is the difference of these two values of energy gaps derived from PPT and PL spectroscopy.