Esterification of valeric acid over PTA supported mesoporous Al-SBA-15 as efficient solid acid catalysts

Journal of Porous Materials - Valeric acid can be produced by selective hydrogenation of biomass-derived levulinic acid. The present work aims to synthesize ethyl valerate (EV), a fuel, fuel...     

Pixel rearrangement based statistical restoration scheme reducing embedding noise

In this paper, a block based steganographic algorithm has been proposed where a sequence of secret bits are embedded into a set of pixels by rearranging the pixel locations. This algorithm has been devised as an improvement over existing statistical restoration based algorithms in order to reduce the additive noise which occurs due to embedding. It is shown that the proposed scheme substantially reduces the additive noise compared to existing statistical restoration based schemes.     

A Hybrid Clustering Approach Based Q-Leach in TDMA to Optimize QOS-Parameters

An Orthogonal frequency part multiplexing suffers from a considerable challenge due to a high peak to average power ratio (PAPR). Hence, an effective method such as partial transmits sequence (PTS) can avert this defiance by limit the design of PAPR. Therefore, an improving PAPR reduction performance via a novel approach is proposed by detaching each subblock into two parts furthermore exchanges the first sample with the final selection in each portion of the subblock to generate a new partitioning scheme. Several typical traditional segmentation schemes are used to analyze and apply the presented algorithm, such as adjacent, interleaving, and pseudo-random schemes. Besides, two scenarios are adopted based on simulation software in which the number of subcarriers is set to 128 and 256. Based on the results, a superior PAPR reduction performance is achieved based on the improved segmentation schemes regarding traditional strategies in both systems. Moreover, the enhanced adjusted PTS scheme poses a low computational complexity compared with that of the conventional schemes.

     

Encrypted Network Traffic Classification and Resource Allocation with Deep Learning in Software Defined Network

Wireless Personal Communications - The climate has changed absolutely in every area in just a few years as digitized, making high-speed internet service a significant need in the future. Future...     

Mesoporous Ru/Sn-SBA-15 catalysts: synthesis,characterization and catalytic activity towards hydrogenation of levulinic acid

Journal of Porous Materials - Among the various biomass-derived platform chemicals, levulinic acid (LA) has been identified as one of the top-10 important molecules by Department of Energy, United...     

Polyethers with phosphate pendant groups by monomer activated anionic ring opening polymerization: Syntheses,characterization and their lithium-ion conductivities

This paper describes the preparations and lithium-ion conductivities of various solid polymer electrolytes for potential use in high-energy density lithium-ion batteries. The ring opening polymerization of epoxides (M1–M6), catalyzed by Zn(II), Cu(II) and Cd(II) complexes in the presence of tetrabutylammonium bromide (TBAB), yielded polyethers (P1–P6) in which phosphates were attached as pendant groups. A reaction condition where Zn(II) catalyst used slightly excess to TBAB increased the polymerization rate remarkably and yielded the polyethers with higher molar masses in a short time. These polymerizations proceeded following a “monomer activated anionic ring opening polymerization” mechanism. These living like polymerizations also progressed according to “formation of polymer chain per initiator” model. The solid-state lithium-ion conductivities of these polymers were examined using lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The conductivity of one of the solid polymer electrolytes with 40 wt% of LiTFSI was 5.2 × 10⁻⁵ S cm⁻¹ at room temperature and 2.9 × 10⁻⁴ S cm⁻¹ at 80 °C.     

Nanoparticle-filled silane films as chromate replacements for aluminum alloys

Silane surface treatments have been developed as an alternative for toxic and carcinogenic chromate-based treatments for years. It is consistently observed that ultra-thin silane films offer excellent corrosion protection as well as paint adhesion to metals. The silane performance is comparable to, or in some cases better than, that of chromate layers. The most recent studies also showed that the silane films can be thickened and strengthened by loading of a small amount of nanoparticles such as silica and alumina into the films resulting in enhanced corrosion protection of aluminum alloys.     

Sliding Wear Characteristics of Friction Stir Processed CAST ZK60 Magnesium Alloy Under Different Applied Loads

Wear resistance and poor friction are the two main draw backs of magnesium alloys that restricts structural applications. Therefore it is essential to enhance the tribological properties of magnesium alloys with the help of surface engineering without causing significant antagonistic effects on the properties of the base metal. Friction stir processing (FSP) is one of the promising thermo-mechanical processing techniques that alters the micro-structural and tribological properties of the material with low production at less period of time. Hence, this investigation enable us to study an effect of friction stir processing on wear characteristics of cast ZK60 magnesium alloy. A pin-on-disc wear testing machine was used to evaluate the wear resistance of surface modified ZK60 magnesium alloy. The result shows that the surface modification by FSP resulted in 26% increase in hardness compared to parent metal. The formation of finer grains and subsequent increase in hardness are the main reasons to improve wear resistance of FSPed ZK60 magnesium alloy.     

EFFECT OF TEMPERATURE ON THE ADSORPTION OF METHYLENE BLUE DYE ONTO SULFURIC ACID–TREATED ORANGE PEEL

The present study explains the preparation and application of sulfuric acid–treated orange peel (STOP) as a new low-cost adsorbent in the removal of methylene blue (MB) dye from its aqueous solution. The effects of temperature on the operating parameters such as solution pH, adsorbent dose, initial MB dye concentration, and contact time were investigated for the removal of MB dye using STOP. The maximum adsorption of MB dye onto STOP took place in the following experimental conditions: pH of 8.0, adsorbent dose of 0.4 g, contact time of 45 min, and temperature of 30°C. The adsorption equilibrium data were tested by applying both the Langmuir and Freundlich isotherm models. It is observed that the Freundlich isotherm model fitted better than the Langmuir isotherm model, indicating multilayer adsorption, at all studied temperatures. The adsorption kinetic results showed that the pseudo-second-order model was more suitable to explain the adsorption of MB dye onto STOP. The adsorption mechanism results showed that the adsorption process was controlled by both the internal and external diffusion of MB dye molecules. The values of free energy change (ΔG ^o) and enthalpy change (ΔH ^o) indicated the spontaneous, feasible, and exothermic nature of the adsorption process. The maximum monolayer adsorption capacity of STOP was also compared with other low-cost adsorbents, and it was found that STOP was a better adsorbent for MB dye removal.