Effective removal of automobile exhausts over flower-like Ce1−xCuxO2 nanocatalysts exposed active {100} plane

This work elucidates the synthesis and characterization of copper ions incorporated ceria(Ce_(1-x)Cu_xO_2)nanocatalysts with 3 D flower-like and nanocrystalline morphology for the purification of automobile exhausts. XRD and Raman results confirm the presence of copper ions in ceria. The 3 D flower-like and nanocrystalline morphology exhibited by these catalysts were seen by FESEM images. HRTEM and SAED results confirm that(100) plane is dominantly presented in 3 D flower-like Ce_(1-x)Cu_xO_2 catalysts when compared to nanocrystalline morphology. The textural properties of synthesized catalysts was done with the help of N2 sorption study, which confirms that flower-like Ce_(1-x)Cu_xO_2 catalysts show high surface area and pore volume. The existence of Ce~(3+), Ce~(4+), Cu~+ and Cu~(2+) ions in the catalyst were examined by XPS and DR UV-Vis techniques. Oxygen storage capacity(OSC) of the catalysts was studied by H_2-TPR analysis. These characterization results elucidate the presence of dominant active sites(Ce~(3+), Ce~(4+), Cu~+and Cu~(2+)) and {100} plane in the flower-like morphology compared to nanocrystalline. The catalytic activity of synthesized Ce_(1-x)Cu_xO_2 catalysts was tested for removal of CO, HC_x and NO gases from automobile emission with respect to the copper content and morphology. The obtained results indicate that the presence of optimum amount of copper in ceria with flower-like morphology is essential for the removal of CO, HC_x and NO at low temperature via redox process, which is due to the presence of active sites on the dominant {100} plane.     

Synthesis and application of biocompatible nontoxic nanoparticles for reclamation of Ce3+ from synthetic wastewater: Toxicity assessment,kinetic, isotherm and thermodynamic study

The aim of present study is to synthesize forsterite nanoparticles(FRST) for the reclamation of cerium ions(Ce~(3+)) from synthetic wastewater.The aim to synthesize FRST nanoparticles is due to its biocompatible and nontoxic nature.The formation of nanoparticles with average diameter of 58 nm was confirmed by TEM analysis.SEM images of bare FRST nanoparticles show a heterogeneous surface with porous nature.BET surface area of FRST nanoparticles is calculated to be 33.69 m~2/g.The significant uptake of Ce~(3+) ions can be obtained for all the selected concentrations(25-150 mg/L) within 2 h of adsorbent—adsorbate interaction.The pH study shows that by increasing pH from acidic to alkaline range,higher removal can be achieved.Temperature study demonstrates the endothermic nature of Ce~(3+)adsorption.The value of sticking probability suggests very high sticking probability of Ce~(3+) ion for FRST nanoparticles.Ce~(3+) uptake is favored by higher temperature and with the increase in temperature from298 to 328 K,Langmuir adsorption capacity increases from 36.45 to 42.99 m~2/g.Applicability of FRST nanoparticles was also investigated for other light and heavy rare earth elements in single solute and multisolute systems,FRST nanoparticles show the significant removal of divalent metallic pollutants as well.The assessment of chemical toxicity of treated wastewater was carried out with the bioluminescent photobacterium(Vibrio fischeri) and decreased toxicity was observed in treated water samples.The outcome of present study suggests that the FRST nanoparticles can be efficiently utilized for the removal of Ce~(3+) ions and a wide range of other pollutant species as well.     

Enhanced Densification of PM Steels by Liquid Phase Sintering with Boron-Containing Master Alloy

Metallurgical and Materials Transactions A - Reaching high density in PM steels is important for high-performance applications. In this study, liquid phase sintering of PM steels by adding...     

Growth and properties of benzil doped benzimidazole (BMZ) single crystals

In the present work, we have made an attempt to study the effect of benzil doping on the properties of benzimidazole single crystals. For this purpose we have grown pure and benzil doped benzimidazole single crystals by vertical Bridgman technique. The grown crystals were characterized by various characterization techniques. The presence of dopants confirmed by powder X-ray diffraction (XRD). Crystalline perfection of the grown crystals has been analysed by high-resolution X-ray diffraction (HRXRD). The transmittance, electrical property and mechanical strength have been analysed using UV-vis-NIR spectroscopic, dielectric and Vicker's hardness studies. The relative second harmonic generation efficiency of pure and doped benzimidazole crystals measured using Kurtz powder test.     

Microbial diversity analysis of long term operated biofilm configured anaerobic reactor producing biohydrogen from wastewater under diverse conditions

This communication provides an insight into the composition of the microbial community survived in the biofilm configured anaerobic reactor operated for biohydrogen (H₂) production using wastewater as substrate under diverse conditions for past four years. PCR amplified 16S rDNA product (at variable V3 region using universal primers 341F and 517R) was separated by using denaturing gradient gel electrophoresis (DGGE) to identify the diversity in microbial population survived. The phyologenetic profile of the bioreactor showed significant diversity in the microbial community where major nucleotide sequences were affiliated to Class Clostridia followed by Bacteroidetes, Deltaproteobacteria and Flavobacteria. Clostridium were found to be dominant in the microbial community observed. The controlled growth conditions, application of pre-treatment to biocatalyst, operation with specific pH and variation in substrate composition are reasoned for the robust acidogenic culture identified in the bioreactor. Most of the operational taxonomic units (OTUs) observed in the bioreactor are capable to undergo acetate producing pathway, feasible for effective H₂ production.     

Optimum Design of Bridge Abutments under Seismic Conditions: Reliability-Based Approach

The paper focuses on the reliability-based design optimization of gravity wall bridge abutments when subjected to active condition during earthquakes. An analytical study considering the effect of uncertainties in the seismic analysis of bridge abutments is presented. Planar failure surface has been considered in conjunction with the pseudostatic limit equilibrium method for the calculation of the seismic active earth pressure. Analysis is conducted to evaluate the external stability of bridge abutments when subjected to earthquake loads. Reliability analysis is used to estimate the probability of failure in three modes of failure viz. sliding failure of the wall on its base, overturning failure about its toe (or eccentricity failure of the resultant force) and bearing failure of foundation soil below the base of wall. The properties of backfill and foundation soil below the base of abutment are treated as random variables. In addition, the uncertainties associated with characteristics of earthquake ground motions such as horizontal seismic acceleration and shear wave velocity propagating through backfill soil are considered. The optimum proportions of the abutment needed to maintain the stability are obtained against three modes of failure by targeting various component and system reliability indices. Studies have also been made to study the influence of various parameters on the seismic stability.     

Optimum Design for External Seismic Stability of Geosynthetic Reinforced Soil Walls: Reliability Based Approach

In this paper, an analytical study considering the effect of uncertainties in the seismic analysis of geosynthetic-reinforced soil (GRS) walls is presented. Using limit equilibrium method and assuming sliding wedge failure mechanism, analysis is conducted to evaluate the external stability of GRS walls when subjected to earthquake loads. Target reliability based approach is used to estimate the probability of failure in three modes of failure, viz., sliding, bearing, and eccentricity failure. The properties of reinforced backfill, retained backfill, foundation soil, and geosynthetic reinforcement are treated as random variables. In addition, the uncertainties associated with horizontal seismic acceleration and surcharge load acting on the wall are considered. The optimum length of reinforcement needed to maintain the stability against three modes of failure by targeting various component and system reliability indices is obtained. Studies have also been made to study the influence of various parameters on the seismic stability in three failure modes. The results are compared with those given by first-order second moment method and Monte Carlo simulation methods. In the illustrative example, external stability of the two walls, Gould and Valencia walls, subjected to Northridge earthquake is reexamined.     

Toward prediction of microstructural evolution during laser surface alloying

The stability of tungsten carbide particles in iron-rich and nickel-rich liquid during the laser surface alloying (LSA) process was investigated. Kinetic calculations indicate a rapid dissolution of tungsten carbide particles in iron-rich liquid, as compared with the dissolution rate in nickel-rich liquid. Optical microscopy indicated a heterogeneous microstructure around the tungsten particles that is in agreement with concentration gradients predicted by kinetic calculations. The work demonstrates the applicability of computational thermodynamics and kinetic models for the LSA process.     

Renal artery stent placement for the management of ischemic nephropathy

The aim of this work was to determine the oesophageal transit time (OTT) of a bolus using the biomagnetic technique and compare the results to those obtained by means of scintigraphy. For the biomagnetic evaluation, a test meal (yoghurt) uniformly labelled with 5 g of powder ferrite was swallowed in a single gulp by 19 normal volunteers in the upright position. One sensor (first order gradiometer) was placed at the furcula and a second one at the xiphoid process to detect the passage of the test meal and the magnetic signal output was recorded in a computer. The OTT was determined by plotting the voltage signal against time. The scintigraphic technique was used in the same volunteers: the test meal was labelled with less than 350 MBq of 99mTc-phytate and swallowed in the same way. The bolus transit was recorded at 4 frames s(-1) (100-120 frames acquisition) and the OTT was determined by drawing two regions of interest in the same areas as the sensors. The results were determined by plotting counts against time. The averages for OTTs were 3.8 +/- 0.8 s for the scintigraphic technique and 4.6 +/- 0.9 s for the biomagnetic technique. Although scintigraphic OTT was significantly shorter than magnetic OTT, there was a significant correlation between them. We conclude that the biomagnetic study may be used to evaluate OTT.     

Municipal solid waste fueled power generation for India

The energy policy of the Government of India aims to ensure adequate energy supplies at minimal cost, achieving self-sufficiency in energy supplies and protecting the environment from the adverse impact of using energy resources in an injudicious manner. To achieve its goals, the Indian Government invited the support of the private sectors as before for the development and exploitation of environmentally friendly new and renewable sources of energy. This paper proposes one such technology of generating electricity from municipal solid waste (MSW), to be implemented in Tamilnadu State. To do so, a complete feasibility survey has been conducted with a probable developer and the benefits of this project are compared with the existing wind farm project to attract more investors in the future.