Hydrothermal synthesis and characterization of Dy-doped CeVO_4 nanorods used for photodegradation of methylene blue and rhodamine B

Pure CeVO_4 and Dy-doped CeVO_4 nanorods containing different weight contents of Dy dopant were synthesized by hydrothermal method.Effect of Dy dopant on photodegradation of methylene blue(MB)and rhodamine B(RhB) was evaluated under UV light irradiation within 80 min.Pure CeVO_4 and Dydoped CeVO_4 nanorods were characterized by X-ray diffraction(XRD),Raman spectroscopy,transmission electron microscopy(TEM) and UV-visible spectroscopy.In this research,CeVO_4 nanorods are tetragonal phase with the detection of main peak shift after being doped with Dy.The length of nanorods is deceased from 50 to 200 nm for pure CeVO_4 to 50-100 nm for 3% Dy-doped CeVO_4.Photodegradation of MB and RhB by CeVO_4 nanorods under UV light irradiation is improved by Dy-dopant that plays the role in accepting electrons and reducing electron-hole recombination.MB and RhB solutions degraded by 3% Dy-doped CeVO_4 nanorods was 94% and 93% within 80 min,respectively.     

Conversion of Methylesters to Hydrocarbons Over Zn-Modified H-ZSM-5 Zeolite Catalyst

The conversion of methyloctanoate has been studied on Zn- and H-ZSM-5 catalysts. While the addition of Zn has a promoting effect in the aromatization of light alkanes, the effect is much lower when the feed is a methylester. Direct ring closure at the C adjacent to the CO group has been identified.     

Characterization of Li1−x Ni1+x O2 prepared using succinic acid as a complexing agent

Li_1−x Ni_1+x O₂ was prepared by a polymerized complex method using succinic acid as a complexing agent. Ethanolic solutions of lithium acetate dihydrate, nickel acetate tetrahydrate, and succinic acid were mixed to form carboxylate precursors, which were subsequently calcined at 650–800°C for 14–48 h. TGA curves of metal acetates, succinic acid, and the precursors were characterized to determine weight loss and formation temperature of the oxide. By using XRD, SEM, and EDX, pure crystals of Li_1−x Ni_1+x O₂ were detected at 750 and 800°C. The maximum and minimum intensity ratios of XRD spectra show that the optimum calcination condition is 750°C for 40 h. At 650–800°C, the particle size distribution is in the range of 0.35–39 μm. The text was submitted by the authors in English.     

Predicting performance of radial flow type impeller of centrifugal pump using CFD

The main objective of this work is to use the computational fluid dynamics (CFD) technique in analyzing and predicting the performance of a radial flow-type impeller of centrifugal pump. The impeller analyzed is at the following design condition: flow rate of 528 m³/hr; speed of 1450 rpm; and head of 20 m or specific speed (N_s) of 3033 1/min in US-Units. The first stage involves the mesh generation and refinement on domain of the designed impeller. The second stage deals with the identification of initial and boundary conditions of the mesh-equipped module. In the final stage, various results are calculated and analyzed for factors affecting impeller performance. The results indicate that the total head rise of the impeller at the design point is approximately 19.8 m. The loss coefficient of the impeller is 0.015 when 0.6 < Q/Q_design < 1.2. Maximum hydraulic efficiency of impeller is 0.98 at Q/Q_design = 0.7. Based on the comparison of the theoretical head coefficient and static pressure rise coefficient between simulation results and experimental data, from previous work reported in the literature [Guelich, Kreiselpumpen, Springer, Berlin, 2004], it is possible to use this method to simulate the performance of a radial-flow type impeller of a centrifugal pump. This paper was recommended for publication in revised form by Associate Editor Seungbae Lee Somchai Wongwises is currently a Professor of Mechanical Engineering at King Mongkut’s University of Technology Thonburi, Bangmod, Thailand. He received his Doktor Ingenieur (Dr.Ing.) in Mechanical Engineering from the University of Hannover, Germany, in 1994. His research interests include two-phase flow, heat transfer enhancement, and thermal system design. Professor Wongwises is the head of the Fluid Mechanics, Thermal Engineering and Two-Phase Flow Research Laboratory (FUTURE). Suthep Kaewnai obtained a B. S. degree in Mechanical Engineering, 1980 from the King Monkut’s University of Technology Thonburi and M. S. degree in Mechanical Engineering, 1983 from Chulalongkorn University. He is currently an assistant professor at King Mongkut’s University of Technology Thonburi. Suthep’s research interests are in the area of pumps and small hydroturbine. Manuspong Chamaoot received a B. S. degree, 1972 and M.S. degree in Mechanical Engineering, 1979 from the King Monkut’s University of Technology Thonburi. He is currently an assistant professor at King Monkut’s University of Technology Thonburi. His research interests are in the field of mechanical vibration for rotating equipment and computational fluid dynamics.     

Experimental and numerical studies on heat transfer enhancement for air conditioner condensers using a wavy fin with a rectangular winglet

Journal of Mechanical Science and Technology - The air side thermal performance of wavy fins with rectangular winglets are studied using experimental and numerical methods. The following parameters...     

Facile sonochemical synthesis and photocatalysis of Ag nanoparticle/ZnWO_4-nanorod nanocomposites

A facile sonochemical method was developed to synthesize metallic Ag spherical nanoparticles on the surface of ZnWO_4 nanorods by forming heterostructure Ag/ZnWO_4 nanocomposites.The Ag/ZnWO_4 nanocomposites were characterized by X-ray powder diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS).The experimental results showed that fcc metallic Ag nanoparticles were supported on surface of monoclinic sanmartinite ZnWO_4 nanorods.The Ag3d_(3/2) and Ag 3 d_(5/2) peaks have well-separated binding energies of 6.00 eV,certifying the existence of metallic Ag.The Ag/ZnWO_4 nanocomposites were evaluated for photodegradation of methylene blue(MB)induced by ultraviolet-visible(UV-Vis)radiation.In this research,heterostructure 10 wt% Ag nanoparticle/ZnWO_4-nanorod composites have the highest photocatalytic activity of 99%degradation of MB within 60 min.The increase in photocatalytic activity was the result of photoinduced electrons in conduction band of ZnWO_4 that effectively diffused to metallic Ag spherical nanoparticles and the inhibition of electron-hole recombination process.     

Further purification of food‐grade alcohol to make a congener‐free product

Most alcoholic beverages contain small amounts of chemicals other than ethanol, the congeners. These are byproducts of the fermentation process of the substrate. Congeners are implicated in contributing to hangover (veisalgia) symptoms and it is therefore considered expedient to remove these substances. This research compared 12 established vodka brands with a new product by GC‐MS‐olfactometry. A new vodka produced in Iowa from corn was found to be the purest while another corn‐based vodka and a potato‐based vodka contained eight and 12 impurities each. Eight other commercially available vodkas contained 15–19 impurities and three vodkas showed more than 30 impurities. Neither the raw material nor the country of origin made a difference to the level of the impurities. However, the treatment process was of great importance in terms of reaching lower impurity levels. Multiple distillations and filtration did not seem to benefit the quality, nor did charcoal and activated carbon alone. However, one vodka based on a multiple distilled neutral grain spirit process from corn contained zero measurable volatile impurities. The particular treatment process involved ozonation, followed by granular activated carbon and a nano‐noble‐metal catalysis and adsorption. Copyright © 2015 The Institute of Brewing & Distilling     

Microwave-assisted synthesis of ZnO nanostructure flowers

Hexagonal ZnO nanostructure flowers were successfully synthesized from a 1:15 molar ratio of Zn(CH₃COO)₂2H₂O to KOH using 180 W microwave radiation for 20 min. The product phase was detected using X-ray diffraction (XRD) and selected area electron diffraction (SAED). A diffraction pattern was also simulated and was found to be in accordance with those of the experiment and the JCPDS database. Raman spectrometry revealed the presence of four vibration peaks at 337.85, 381.13, 437.54 and 583.30 cm^? 1. The product, spear-shaped nanorods in flower-like clusters, was characterized using both scanning electron microscopy (SEM) and transmission electron microscopy (TEM). High resolution TEM (HRTEM) showed that growth of the spear-shaped nanorods was in the [001] direction, which was normal to the (002) planes composing a lattice fringe of the nanorods. A formation mechanism of hexagonal ZnO nanostructure flowers was also proposed.     

Effects of ethylenediamine to water ratios on cadmium sulfide nanorods and nanoparticles produced by a solvothermal method

Cadmium sulfide nanorods and nanoparticles were successfully produced by a solvothermal reaction at 200 °C for 24 h using ethylenediamine and water as pure and mixed solvents. The products were analyzed by X-ray diffraction, Raman spectroscopy and transmission electron microscopy. In pure ethylenediamine, they show the hexagonal structure CdS nanorods with 0.2-2 μm long and 30 nm diameter, and the 1LO and 2LO modes at 299.36 and 600.72 cm^− 1, respectively. Growth of CdS nanorods is along the [001] direction, interpreted by HRTEM images and SAED patterns. In the 50:50 vol.% of ethylenediamine:water mixed solvents, the length of CdS nanorods decreased to 100-200 nm. The CdS nanoparticles were produced when pure water was used.