Suitable energy platform significantly improves charge separation of g-C_3N_4 for CO_2 reduction and pollutant oxidation under visible-light

The photocatalytic activities of g-C_3N_4 can be significantly improved by increasing life time of the photogenerated charges. Here, in this work we introduced TiO_2 as proper energy platform to accept the photogenerated electrons from g-C_3N_4 during photocatalysis. The nanophotocatalysts formed from the combination of a suitable amount of TiO_2 nanoparticles and g-C_3N_4 nanosheets showed 8.75 and 4.22% enhancement in photocatalytic activities for CO_2 reduction and 2-chlorophenol(2-CP) degradation under visible light illumination as compared to bare g-C_3N_4. Based on the surface photovoltage spectra, photoluminescence spectra and examination of formed hydroxyl radicals, it was confirmed that these enhanced photoactivities were attributed to the much-improved charge separation via the electron transfer from g-C_3N_4 to TiO_2. From trapping experiments,it was found that hydroxyl radicals were the major species involved in the photocatalytic degradation of 2-CP.This study is helpful to synthesize efficient photocatalysts to cope with energy and environmental issues.     

Effect of Co substitution on the structural, electrical, and magnetic properties of Bi0.9La0.1FeO3 by sol-gel synthesis

Cobalt (Co)-doped Bi_0.9La_0.1FeO₃ multiferroics were synthesized by a sol-gel method based on the autocombustion technique. As-synthesized powder was examined using various characterization techniques to explore the effect of Co substitution on the properties of Bi_0.9La_0.1FeO₃. X-ray diffraction reveals that Co-doped Bi_0.9La_0.1FeO₃ preserves the perovskite-type rhombohedral structure of BiFeO₃, and the composition without Co preserves the original structure of the phase; however, a second-phase Bi₂Fe₄O₉ has been identified in all other compositions. Surface morphological studies were performed by scanning electron microscopy. Temperature-dependent resistivity of the samples reveals the characteristic insulating behavior of the multiferroic material. The resistivity is found to decrease with the increase both in temperature and Co content. Room temperature frequency-dependent dielectric measurements were also reported. Magnetic measurements show the enhancement in magnetization with the increase in Co content.     

Strength of Concrete Filled Steel Tubular Columns

Introduction The steel tube in a concrete filled tubular column (CFT) acts as both longitudinal and lateral reinforcement, and is thus subjected to biaxial stresses of longitudinal compression and hoop tension. At the same time, con- crete is stressed tri…     

Synthesis and superconductivity of (Ag)x/CuTl-1223 composites

Series of(Ag)x/(Cu0.5Tl0.5Ba2Ca2Cu3O10-δ) {(Ag)x/Cu Tl-1223} nano-superconductor composites were synthesized with different concentrations(i.e. x ? 0 4.0 wt%) of silver(Ag) nanoparticles. Low anisotropic Cu Tl-1223 superconducting matrix was prepared by solid-state reaction and Ag nanoparticles were prepared by a sol–gel method separately. The required(Ag)x/Cu Tl-1223 composition was obtained by the inclusion of Ag nanoparticles in Cu Tl-1223 superconducting matrix. Structural, morphological, compositional and superconducting transport properties of these composites were investigated in detail by x-ray diffraction(XRD), scanning electron microscopy(SEM), energy dispersive x-rays(EDX)spectroscopy and four-point probe electrical resistivity(ρ) measurements. The inclusion of Ag nanoparticles enhanced the superconducting properties without affecting the tetragonal structure of the host Cu Tl-1223 matrix. The improvement in superconducting properties of(Ag)x/Cu Tl-1223 composites is most likely due to enhanced inter-grains coupling and increased superconducting volume fraction after the addition of metallic Ag nanoparticles at the inter-crystallite sites in the samples. The presence of Ag nanoparticles at the grain-boundaries may increase the number of flux pinning centers, which were present in the form of weak-links in the pure Cu Tl-1223 superconducting matrix.     

Enhanced ductility of Mg–3Al–1Zn alloy reinforced with short length multiwalled carbon nanotubes using a powder metallurgy method

Mg–3Al–1Zn–CNTs composites, with different weight fractions(0.25–1.0 wt%) of carbon nanotubes(CNTs) were successfully fabricated via a powder metallurgy method. The processing parameters were adopted in such a way to have uniform dispersion of short length CNTs without any damage, as well as re fi ned and dissolved β phases structures throughout the composite matrix. The composite exhibited impressive increase in microhardness(about+23%) and tensile failure strain value(about+98%) without signi fi cant compromise in tensile strength, compared to the un-reinforced Mg–3Al–1Zn alloy. The synthesized composites can be used in automotive and aerospace industries due to their low density and high speci fic strength.     

Epidemiological modeling of passive worm propagationon the P2P file-sharing network

The peer-to-peer(P2P) file-sharing network as a vehicle of disseminating files has become very popular.The appearance of dozens of kinds of passive worms on this network has,however,made it unsecured.This problem has been paid attention and a few of models for passive worm propagation has been presented.Unfortunately,the dynamic properties of this network are ignored in these models.Given the fact,the characteristics of both this network and the passive worm are identified,and on this basis a new mathematical model of passive worm propagation on the P2P network is presented in applying epidemiology in this paper.Note that the dynamic properties of this network are considered in the presented model.The model has been validated by large scale simulation experiments,which demonstrates that the presented model may be used for analyzing the behaviors of passive worms and predicting the trend of their propagation.     

Tunability of physical properties of (Cd:Zn)S thin film by Close Space Sublimation Process (CSSP)

The present paper reports on a systematic study of the influence of Zn alloying on the structural and optical properties of Cd1 xZnxS thin films. X-ray diffraction study for structural analysis reveals that the two binary compounds have been completely transformed into ternary compound with hexagonal (wurtzite) structure with preferred orientation along c-direction with (002) planes. The optical properties such as optical constants and band gap energy of the films were examined by using spectroscopic ellipsometer and Photospectrometery. It was found that the optical constants (n and k) decrease with the addition of Zn content in the alloy. It was also confirmed that the band gap increases with increasing Zn amount in the alloy and is attributed to quantum size effect in the grain size. Raman spectroscopy analysis shows one dominant phonon band at 326 cm 1, the so-called longitudinal optical (LO) mode for all the alloy composition (x). The appearance of a single phonon band in the Raman spectra established the formation of single phase hexagonal structured Cd1 xZnxS thin film. The LO band is asymmetrically broaden and high frequency shifted due to potential fluctuation caused by the dopant material. The AFM results showed that the surface roughness was decreased with increasing Zn content.     

Biodiversity loss and its impact on humanity

The most unique feature of Earth is the existence of life, and the most extraordinary feature of life is its diversity. Approximately 9 million types of plants, animals, protists and fungi inhabit the Earth. So, too, do 7 billion people. Two decades ago, at the first Earth Summit, the vast majority of the world's nations declared that human actions were dismantling the Earth's ecosystems, eliminating genes, species and biological traits at an alarming rate. This observation led to the question of how such loss of biological diversity will alter the functioning of ecosystems and their ability to provide society with the goods and services needed to prosper.