DIAL,a system for atmospheric methane measurement over Guwahati: development and results

The article discusses the development and operational details of Differential Absorption LiDAR (DIAL) for the measurement of methane concentration in the semi-urban environment of Gauhati University. The system comprises two specifically selected wavelengths in 3 μm range: one is an absorbing wavelength (λ_on) and the other is non-absorbed (λ_off) by methane molecules. Pulses of 10 ns for the two wavelengths are transmitted alternately for interleaved sampling of differential absorption. The pulse repetition rate is variable between 1 and 20 Hz. The slope and integrated target approaches are adopted to calculate the methane concentration, and observed figures are compared with globally reported values.     

Computer-aided kinematic analysis of basic spatial mechanisms

Using the spherical coordinate system in conjunction with the principle of algebraic correspondence between the displacement equations of the plane, spherical and spatial four-bar mechanisms and the plane and spatial slider-crank mechanisms, an efficacious procedure has been developed to carry out kinematic analysis for the coupler and output link of the mechanisms. The iteration-free nature of the procedure precludes any non-convergence problem and the inherent complexity of the 3-dimensional analysis is mitigated substantially.     

Looking beyond lithium-ion technology – Aqueous NaOH battery

The objective of this work is to investigate a water based sodium battery technology. The new concept proposed here for an aqueous rechargeable battery is replacing lithium hydroxide with a sodium hydroxide electrolyte in the patented technology developed at Murdoch University. Alternative energy storage system using abundantly available sodium as the aqueous electrolyte coupled with Zn anode and environmentally friendly MnO₂ cathode are investigated and found feasible. Sodium intercalation and de-intercalation mechanism is identified in MnO₂|NaOH|Zn cell yielding 225 against 142 mAh/g for LiOH counterpart. The preliminary studies of the aqueous NaOH battery showed improved energy density and voltaic efficiency.     

Modeling and simulation of curing kinetics for the cardanol-based vinyl ester resin by means of non-isothermal DSC measurements

The cure kinetics of vinyl ester-styrene system was studied by non-isothermal differential scanning calorimetric (DSC) technique at four different heating rates. The kinetic parameters of the curing process were determined by isoconversional method for the kinetic analysis of the data obtained by the thermal treatment. Activation energy (E_a = 56.63 kJ mol⁻¹) was evaluated for the cure process and a two-parameter (m, n) autocatalytic model was found to be the most adequate to describe the cure kinetics of the studied cardanol-based vinyl ester resin. Non-isothermal DSC curves, as obtained by using the experimental data, show good agreement with the DSC curves obtained by theoretically calculated data.     

Isolation and Evaluation of Stearin and Olein Fractions from Rice Bran Oil Fatty Acid Distillate by Detergent Fractionation and Conversion into Neutral Glycerides by Autocatalytic Esterification Reaction

Detergent fractionation (Lanza process) offers a valuable separation process for edible oils that contain varying amounts of saturated and unsaturated fatty acids. The rice bran oil fatty acid distillate (RBOFAD), obtained as a major byproduct of rice bran oil deacidification refining process, was fractionated by detergent solution into a fatty acid mixture as follows: low-melting (19.00 °C) fraction of fatty acids as olein fraction (44.50 g/100 g) and high-melting (49.00 °C) fatty acids as stearin fraction (37.15 g/100 g). A high amount of palmitic acid (42.75 wt%) is present in stearin fraction, while oleic acid is higher (48.21 wt%) in the olein fraction. The stearin and olein fractions of RBOFAD with very high content of free fatty acids are converted into neutral glycerides by autocatalytic esterification reaction with a theoretical amount of glycerol at high temperatures (130–230 °C) and at a reduced pressure (30 mmHg). Acid value, peroxide value, saponification value, and unsaponifiable matters are important analytical parameters to identity for quality assurance. These neutral glyceride-rich stearin and olein fractions, along with unsaponifiable matters, can be used as nutritionally and functionally superior quality food ingredients in margarine and in baked goods as shortenings.     

Fusion Based Feature Extraction and Optimal Feature Selection in Remote Sensing Image Retrieval

Multimedia Tools and Applications - In remote sensing (RS) community, RSIR (Remote Sensing Image Retrieval) is considered as a tough topic and gained more attention because the data is collected...     

MnO2 cathode in an aqueous Li2SO4 solution for battery applications

A manganese dioxide (MnO₂) cathode with zinc (Zn) as the anode has been investigated using lithium sulphate (Li₂SO₄) as an electrolyte. Previously we demonstrated that cells comprising MnO₂ and lithium hydroxide (LiOH) as an electrolyte can be made rechargeable to over one-electron capacity with a discharge capacity of 150 mAh g⁻¹. Here we have extended our work to assess Li₂SO₄ as an electrolyte and have found that the battery is not rechargeable. Based on the electrochemical (discharge/charge) performance and the products formed following discharge and charge, the mechanism proposed for the sulphate-based media is one of proton insertion into the MnO₂ cathode, rather than the lithium ion insertion observed for the LiOH electrolyte. The addition of bismuth species to the Li₂SO₄-based cell results in a transition to rechargeable behaviour. This is believed to be due to the influence of Bi ions on the formation of soluble Mn³⁺ soluble intermediates. However, the coulombic efficiency of the cell diminishes rapidly with repeated charge/discharge cycles. This confirms that the nature of the Li-containing electrolyte has a marked influence on the electrochemistry of the cell.     

Anodic behavior of zinc in Zn-MnO2 battery using ERDA technique

The commercial, alkaline zinc-manganese dioxide (Zn-MnO₂) primary battery has been transformed into a secondary battery using lithium hydroxide electrolyte. Galvanostatic discharge–charge experiments showed that the capacity decline of the Zn-MnO₂ battery is not caused by the MnO₂ cathode, but by the zinc anode. The electrochemical data indicated that a rechargeable battery made of porous zinc anode can have a larger discharge capacity of 220 mAh/g than a planar zinc anode of 130 mAh/g. The cycling performance of these two anodes is demonstrated. Structural and depth profile analyses of the discharged anodes are examined by X-ray diffraction (XRD) and elastic recoil detection analysis (ERDA) techniques.     

Recent advancements in urea biosensors for biomedical applications

The quick progress in health care technology as a recurrent measurement of biochemical factors such as blood components leads to advance development and growth in biosensor technology necessary for effectual patient concern. The review wok of authors present a concise information and brief discussion on the development made in the progress of potentiometric, field effect transistor, graphene, electrochemical, optical, polymeric, nanoparticles and nanocomposites based urea biosensors in the past two decades. The work of authors is also centred on different procedures/methods for detection of urea by using amperometric, potentiometric, conductometric and optical processes, where graphene, polymer etc. are utilised as an immobilised material for the fabrication of biosensors. Further, a comparative revision has been accomplished on various procedures of urea analysis using different materials‐based biosensors, and it discloses that electrochemical and potentiometric biosensor is the most promise one among all, in terms of rapid response time, extensive shelf life and resourceful design.     

Process modeling, optimization and analysis of esterification reaction of cashew nut shell liquid (CNSL)-derived epoxy resin using response surface methodology

Concept of five-levels-four-factors central composite rotatable design was utilized for the optimization of reaction conditions of cardanol-based vinyl ester resin production, by employing response surfaces methodology, to establish a relationship between the process variables and the extent of conversion under a wide range of operating conditions which resulted in different extent of conversions. The maximum extent of conversion of cardanol-based epoxidised novolac resin (CNE) and methacrylic acid (MA) catalyzed by triphenylphosphine was found to be 95% at optimum set of conditions of molar ratio (1:0.9) between CNE and MA, catalyst concentration (1.49%), reaction temperature (89.96 °C) and reaction time (17,991s). Geometrical representation of the mathematical models in three-dimensional response surface plots and isoresponse contour plots served as a good aid in understanding the behavior of reaction under different operating conditions by only limited sets of experiments. A statistical model predicted that the highest conversion yield of novolac resin would be greater than 95% at the optimized reaction conditions. The predicted values thus obtained were close to the experimental values indicating suitability of the model.