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.     

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.     

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.     

A Small-Scale Pneumatic Conveying Dryer of Rough Rice

This article studies the possibility of reducing the high initial moisture content of wet rough rice using a small-scale low-cost pneumatic conveying dryer as a first stage dryer. The parameters investigated are final moisture content, surface temperature of rough rice, head rice yield, drying rate, power consumption per unit mass of evaporated water, and physical characteristics of rice. Parametric effects of the following variables are examined: velocity of drying air from 20 to 30 m/s, feed rate of rough rice from 150 to 350 kg/h, initial moisture content from 22 to 26% (wet basis), and drying air temperature from 35 to 70°C. From the experimental results, it is found that this drying method can be used for fresh rough rice with an initial moisture content of over 24% (wet basis). The drying process is able to lead to very rapid drying without any grain quality problems such as cracks in the rice kernel. The moisture content can be reduced to approximately 18% (wet basis) or about 5-6% of the initial moisture content within 3-4 s. The optimal drying air temperature is in the range of 50 to 60°C. A comparison of pneumatic conveying drying data obtained from the present study with fluidized bed drying data reported in the open literature is also discussed.     

Diffusion with micro-sorption in bentonite: evaluation by molecular dynamics and homogenization analysis

We here give a numerical analysis method of a diffusion problem including sorption chemistry for bentonite clay. Bentonite predominantly consists of the microscopic smectitic clay minerals (mainly montmorillonite and beidellite). Physico-chemical properties of smectite clays such as diffusivity of chemical species and adsorptivity on surface of clay mineral are characterized by crystalline structure of hydrated smectite minerals. To obtain the microscopic properties of the hydrated smectite, the molecular behavior is analyzed by a molecular dynamic (MD) simulation. We understand at least two types of adsorption are formed on the smectite surface; outer sphere complex and inner sphere complex. The inner sphere complex occurs on the edge sites of clay minerals. The amount of mono-layer of cations on the edge surface is considered as the adsorptivity of smectite in the microscopic level. A multiscale homogenization analysis (HA) is applied to extend the microscopic characteristics of the hydrated smectite to the macroscopic behavior. The diffusion and adsorption of a radioactive specie, cesium (Cs), is introduced by this analysis. The calculated results appear to be acceptable.     

Use of Double Wash-Coatings of Platinum and Zeolite Catalysts to Improve Selective Reduction of NOx by Hydrocarbons

The selective catalytic reduction by hydrocarbons (HC-SCR) of NO _x under lean conditions has been improved by the use of double-layered catalysts with a lower layer of Pt/SiO₂ and an upper layer of a zeolite such as H-, Ce-, and Cu-ferrierite (-FER). H-FER wash-coated over Pt/SiO₂ (H-FER//Pt/SiO₂) performed best among the samples examined. The promotional effect was attributed to the synergy of the oxidation catalyst (Pt/SiO₂) in converting NO into NO₂, which is more reactive to C₃H₆, and the HC-SCR catalyst (H-FER). Cu-FER//Pt/SiO₂ was also effective at widening the temperature window, but with this combination the performance was attributed to a simple summation of the activity of two HC-SCR catalysts that were active at different temperatures.     

Silica gel-assisted solvothermal production of CdS,CuxS(x=1,2) and ZnS with different morphologies

CdS, Cu_xS (x=1, 2) and ZnS with different morphologies were produced by the solvothermal reactions of M(CH₃COO)₂·2H₂O (M=Cd, Cu and Zn) and NH₂CSNH₂ in hexane with and without silica gel as a hard template at 200 °C for 24 h. The product phases were detected using X-ray diffraction (XRD). Different morphologies were characterized using a scanning electron microscope (SEM). The existence of silica gel in modeling morphologies of the sulfides was characterized using Fourier transform infrared (FTIR) spectrometer. Raman spectra of different products show the vibrations at the same wavenumbers, although they are composed of different morphologies. Photoluminescence (PL) emissions of the corresponding phases with different morphologies are at the same values, but their intensities are increased by template adding.     

Flow pattern, mass flow rate, pressure distribution, and temperature distribution of two-phase flow of HFC-134a inside short-tube orifices

New experimental data on the influence of short-tube orifice configuration, including diameter, length, length-to-diameter ratio (L/D), and orientation on the flow pattern, mass flow rate, and pressure distribution of HFC-134a inside the short-tube orifice are presented. Short-tube orifice diameters ranging between 0.605 and 1.2 mm with L/D ranging between 1.87 and 33 are used in the experiments. Three different forms of the metastable liquid flow, which are metastable liquid core flow, conical metastable liquid core flow, and full metastable liquid flow are visually observed. The short-tube orifice diameter has a significant effect on the increase in the flow rate. Conversely, the change in the orientation of the test section has no significant effect on the flow rate. The choke flow phenomenon disappears inside the short-tube orifice when L/D is less than 2.91. Based on the present data, a correlation for predicting the mass flow rate through short-tube orifices is proposed.     

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.