Potassium Ion Impregnated Calcium Oxide as a Nanocrystalline Solid Catalyst for Biodiesel Production from Waste Cotton Seed Oil

<div><p>Vegetable oil and animal fat derived fatty acid methyl esters are commonly known as biodiesel and provide an environment friendly and renewable substitute for the conventional diesel fuel. The present work demonstrates an easy preparation of potassium ion impregnated calcium oxide in nano crystalline form (supported by powder X-ray diffraction and transmission electron microscopic studies) and its application as a solid catalyst for the transesterification of waste cottonseed oil with methanol. The catalyst prepared by impregnating 3.5 wt% of potassium in CaO support was found to show the best catalytic activity among the prepared catalysts. The same catalyst was found to be effective for the complete transesterification of less expensive feedstock, waste cotton seed oil, even in the presence of 10.26 wt% moisture and 4.35 wt% free fatty acid contents. The selected catalyst has also been reused successfully for three catalytic cycles. Few physicochemical properties of the prepared biodiesel sample have been studied and found to be within the acceptable limits of EN 14214 standards.</p></div

Sodium Impregnated Zinc Oxide as a Solid Catalyst for Biodiesel Preparation from a Variety of Triglycerides

<div><p>In the present work, a series of sodium impregnated zinc oxide catalysts were prepared by a wet impregnation method followed by calcinations at different temperatures. The prepared catalysts were characterized by powder X-ray diffraction, Hammett indicator test, scanning electron, and transmission electron microscopic studies. The catalysts prepared by impregnating 5 wt% of sodium in ZnO and calcined at 400°C were used for the virgin cotton seed oil transesterification with methanol. The selected catalysts were able to yield the complete transesterification of the oil to biodiesel, and the catalytic activity was found to depend on (i) the impregnated sodium amount, (ii) the calcination temperature, (iii) methanol to oil molar ratio, (iv) reaction temperature, and (v) the amount of free fatty acid contents in feedstock. The selected catalyst was also used for the transesterification of a variety of feedstock (virgin cottonseed oil, used cotton seed oil, mutton fat, karanja oil, and jatropha oil) having free fatty acid contents in the range of 0.1–8.5 wt% and found to complete the transesterification when free fatty acids were less than 1 wt% in feedstock used.</p></div

Effect of organics, biofertilizers and crop residue application on soil microbial activity in rice – wheat and rice-wheat mungbean cropping systems in the Indo-Gangetic plains

<p>The aim of this study was to investigate the response of soil microbial parameters to nutrient management practices involving organic amendments, farmyard manure (FYM), vermicompost (VC), crop residues (CR) and biofertilizers (BF) in rice–wheat and rice–wheat–mung bean cropping system of the Indo-Gangetic Plains, India. Soil microbial biomass C (C_mic), basal respiration, ergosterol, glomalin, soil enzymes (glucosidases, phosphatases and dehydrogenases), FDA activity, organic carbon (C_org), C_mic-to-C_org ratio and metabolic quotient (qCO₂) were estimated in soil samples collected at 0–15 cm depth. The highest C_org (0.64%) and C_mic (103.8 μg g⁻¹) soil levels occurred in the treatment receiving a combination of VC, CR and BF. Soil respiration, C_org and C_mic-to-C_org ratio were significantly enhanced by the input of CR to plots receiving FYM and VC. The qCO₂ was the highest in plots receiving a combination of FYM, CR and BF followed by control (no nutrient input) and least in plots receiving a combination of VC, crop residue and biofertilizer. These results indicate that the organic practices involving VC, CR and BF improved soil microbial characteristics and C_org in rice–wheat systems.</p

Effect of Multiwalled Carbon Nanotubes on the Conductivity and Swelling Properties of Porous Polyacrylamide Hydrogels

<div><p>Multiwalled carbon nanotubes (MWCNTs) were added to polyacrylamide (PAM) hydrogels in different proportions to tune their electrical and mechanical properties. The choice of MWCNTs as a reinforcement is justified by the fact that these are highly conducting, fairly stable and flexible particles. A series of MWCNT/PAM hydrogels were prepared by freezing method. The characteristic absorption peaks at 1480 and 1213 cm⁻¹ in the FTIR spectra reveal that MWCNTs are embedded in the PAM hydrogels. Powder x-ray diffractograms and thermogravimetric analysis (TGA) images show that the MWCNT/PAM hydrogels are crystalline, more thermally stable and have a higher electrical conductivity than a traditional PAM hydrogel. Scanning electron micrographs reveal about reduced pore size, homogeneous and denser texture. The swelling properties of all these hybrid hydrogels were found to be better than those of the parent PAM hydrogel. The Li–Tanaka equation was employed to produce the swelling parameters. The diffusion coefficients (<i>D</i>_<i>c</i>) of PAM hydrogel is 10 times higher than the literature value. 0.8% MWCNTs reinforced PAM hydrogel has excellent τ_c and electrical conductivity (0.76 mS/cm) with improvements in all properties. Lower <i>D</i>_<i>c</i> of 0.8% MWCNTs/PAM hydrogel reveal that extent of crosslinking is much important than density of the system for a better collective diffusion of the respective solvent.</p> </div

Synthesis, Characterization, and Tribological Evaluation of SDS-Stabilized Magnesium-Doped Zinc Oxide (Zn_0.88Mg_0.12O) Nanoparticles as Efficient Antiwear Lubricant Additives

Pure zinc oxide (ZnO) and magnesium-doped zinc oxide (ZMO) nanoparticles (NPs) with the composition of Zn_0.88Mg_0.12O have been prepared by an autocombustion method. The as-synthesized ZMO nanoparticles were calcined for 2 h at 800 and 1000 °C to yield different-sized ZMO nanoparticles abbreviated as ZMO-1 and ZMO-2, respectively. These nanoparticles have been characterized by powder X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) techniques. The average size of these nanoparticles is found to be 30, 27, 39, and 44 nm, respectively for ZnO, ZMO, ZMO-1, and ZMO-2. A stable dispersion of ZMOs (ZMO, ZMO-1, and ZMO-2) nanoparticles in paraffin oil has been achieved with an appropriate percentage of surfactant sodium dodecylsulfate (SDS), abbreviated as SZMOs (SZMO, SZMO-1, and SZMO-2). The effect of the particle size of these nanoparticles on the tribological behavior of the paraffin oil has been investigated at an optimized additive concentration (0.25% w/v with 0.10% SDS) using different ASTM D4172 and D5183 standards. In addition, a test has been conducted by varying the loads for a 30 min time duration and by varying the test durations at 392 N load. All tribological testing of SZMOs nanoparticles were conducted on a four-ball lubricant tester. These tribological tests revealed that the SZMOs nanoparticles act as excellent antiwear agents and friction modifiers and also enhance the load-bearing ability. Being the smaller particle size, SZMO nanoparticles (27 nm) exhibited better tribological behavior than SZMO-1 (39 nm) and SZMO-2 (44 nm). The morphology of the worn surfaces lubricated with nanoparticles and without SZMOs at a 392 N applied load for 60 min and at higher loads for a 30 min test duration has been examined by scanning electron microscopy (SEM) and contact mode atomic force microscopy (AFM) analyses. Energy-dispersive X-ray (EDX) analysis of the surface lubricated with SZMO nanoparticles shows the presence of zinc, magnesium, iron, carbon, and oxygen on the steel surface which confirmed the adsorption of the additive on the interacting/rubbing surface. These elements form tribochemical film on the interacting surfaces to prevent the metal–metal contact thereby reducing wear and friction

Media 1: Light-into-heat conversion in La₂O₃:Er³⁺-Yb³⁺ phosphor: an incandescent emission

Originally published in Optics Letters on 01 March 2012 (ol-37-5-776

UK-India PV module measurement intercomparison [Abstract]

UK-India PV module measurement intercomparison [Abstract