Methyl ester of karanja oil as an alternative renewable source energy

Methyl ester of karanja oil from Jharkhand region has been prepared by transesterification method. Physical and chemical properties of the karanja oil and that of the methyl ester have been determined. Maximum thermal efficiency of methyl ester has been determined and found to be slightly less than that of the diesel. The brake specific fuel consumption of biodiesel of karanja oil is slightly higher as compared to diesel. Carbon monoxide, hydrocarbon and NO emission of methyl ester and blends have been determined and compared to that of the diesel. It appears that methyl ester of karanja oil is a suitable substitute of petroleum diesel fuel.     

The defluoridation of water by acidic alumina

Fluoride is considered as a major inorganic pollutant present in drinking water. To remove this excess fluoride, defluoridation was done by alumina. In the present study, alumina used was acidic in nature and hence considered as a good fluoride removing adsorbent. Characterization of the adsorbent was done by XRD, SEM, BET and FTIR with BET surface area of 144.27 m²/g. Systematic adsorption experiments were carried out with different process parameters such as contact time, adsorbent mass, pH, temperature and stirring speed. Fluoride adsorption by alumina was highly pH dependent. Maximum fluoride was removed from water at pH 4.4. At very low and very high pH, fluoride removal efficiency was affected. The study of thermodynamic parameters inferred that physical adsorption was dominant with activation energy of 95.13 kJ/mol and endothermic behavior of the process. The kinetics study concluded that pseudo second order kinetics was followed by the adsorption process. Adsorption equilibrium was studied with Langmuir and Freundlich isotherm models. The adsorption process followed Langmuir isotherm with an adsorption capacity of 8.4 mg/g. A regeneration study was proposed in order to reuse the adsorbent for better economy of the process. Finally, a process design calculation was reported to know the amount of adsorbent required for efficient removal of fluoride from aqueous medium.     

Improving Anodes for Lithium Ion Batteries

As energy demands increase for applications such as automotive, military, aerospace, and biomedical, lithium-ion battery capacities are forced to increase in a corresponding manner. For this reason, much research is directed toward the development of improved battery anodes. Carbon nanotubes (CNTs), silicon, tin, and nanocomposites with these metals are the leading candidates for the next generation of lithium-ion battery anodes, leading to capacities 3 to 10 times that of graphite alone. This review looks at some of the studies addressing high capacity lithium-ion battery anodes.     

Use of low dose e-beam irradiation to reduce E. coli O157:H7, non-O157 (VTEC) E. coli and Salmonella viability on meat surfaces

This study determined the extent that irradiation of fresh beef surfaces with an absorbed dose of 1 kGy electron (e-) beam irradiation might reduce the viability of mixtures of O157 and non-O157 verotoxigenic Escherichia coli (VTEC) and Salmonella. These were grouped together based on similar resistances to irradiation and inoculated on beef surfaces (outside flat and inside round, top and bottom muscle cuts), and then e-beam irradiated. Salmonella serovars were most resistant to 1 kGy treatment, showing a reduction of ≤ 1.9 log CFU/g. This treatment reduced the viability of two groups of non-O157 E. coli mixtures by ≤ 4.5 and ≤ 3.9 log CFU/g. Log reductions of ≤ 4.0 log CFU/g were observed for E. coli O157:H7 cocktails. Since under normal processing conditions the levels of these pathogens on beef carcasses would be lower than the lethality caused by the treatment used, irradiation at 1 kGy would be expected to eliminate the hazard represented by VTEC E. coli.     

Catalytic reaction in a circulating fluidized bed downer: Ozone decomposition

Catalytic ozone decomposition reaction was used to study the performance of a 76 mm i.d. and 5.8 m high gas–solid circulating fluidized bed (CFB) downer reactor. Optical fiber probes and an ultraviolet (UV) ozone analyzer were used to obtain comprehensive information about local solids holdup and ozone concentration profiles at different axial and radial positions at superficial gas velocity of 2–5 m/s and solids circulation rates of 50 and 100 kg/m² s. Axial ozone concentration profiles significantly deviated from the plug-flow behavior, with most conversion occurring in the entrance region or flow developing zone of the downer reactor. Strong correlation was observed between the spatial distributions of solids and extent of reaction; higher local solids holdups cause lower ozone concentrations due to higher reaction rates. Radial gradients of the reactant (ozone) concentrations increased in the middle section of the downer, and decreased with increasing superficial gas velocity and solids circulation rate. Contact efficiency, a measure of the interaction between gas and solids indicated high efficiency in the flow developing zone and decreased with height in the fully developed region.     

A clocked high-pass-filter-based offset cancellation technique for high-gain biomedical amplifiers

In this article, a simple offset cancellation technique based on a clocked high-pass filter with extremely low output offset is presented. The configuration uses the on-resistance of a complementary metal oxide semiconductor (CMOS) transmission gate (X-gate) and tunes the lower 3-dB cut-off frequency with a matched pair of floating capacitors. The results compare favourably with the more complex auto-zeroing and chopper stabilisation techniques of offset cancellation in terms of power dissipation, component count and bandwidth, while reporting inferior output noise performance. The design is suitable for use in biomedical amplifier systems for applications such as ENG-recording. The system is simulated in Spectre Cadence 5.1.41 using 0.6 μm CMOS technology and the total block gain is ～83.0 dB while the phase error is <5°. The power consumption is 10.2 mW and the output offset obtained for an input monotone signal of 5 μVpp is 1.28 μV. The input-referred root mean square noise voltage between 1 and 5 kHz is 26.32 nV/√Hz.     

A review of thermodynamic cycles and working fluids for the conversion of low-grade heat

This paper presents a review of the organic Rankine cycle and supercritical Rankine cycle for the conversion of low-grade heat into electrical power, as well as selection criteria of potential working fluids, screening of 35 working fluids for the two cycles and analyses of the influence of fluid properties on cycle performance. The thermodynamic and physical properties, stability, environmental impacts, safety and compatibility, and availability and cost are among the important considerations when selecting a working fluid. The paper discusses the types of working fluids, influence of latent heat, density and specific heat, and the effectiveness of superheating. A discussion of the 35 screened working fluids is also presented.     

Microwave mediated rapid synthesis of chitosan

Chitosan is synthesized by deacetylating chitin with NaOH solution under microwave irradiation. The process describes a rapid synthesis procedure in comparison to conventional methods. The microwave-synthesized chitosan was characterized by Ninhydrin test, Fourier transform-infrared spectroscopy and X-ray diffraction measurements. The experimental results show that the degree of deacetylation increased with increasing irradiation time. A degree of deacetylation of 85.3% was achieved after irradiating chitin with 45% NaOH solution in a microwave for 5.5 min at 900-watt power. This method can be very useful for synthesizing low molecular weight chitosan with rapid and clean chemistry.     

The effect of NiO on the phase formation,thermo-physical properties and sealing behaviour of lithium zinc silicate glass–ceramics

We have prepared lithium zinc silicate (LZS) glasses of compositions (mol%) 17.83Li₂O–17.73ZnO–(53.52 − x)SiO₂–5.25Na₂O–1.25P₂O₅–4.31B₂O₃–x-NiO, where 0.5 ≤ x ≤ 2.0, by the melt quench technique. The effect of NiO on the phase formation, thermo-physical properties and sealing behaviour of LZS glass–ceramics was studied using X-Ray diffraction (XRD), thermo-mechanical analysis (TMA) and microhardness (MH) measurements. It is found that NiO incorporation leads to a change in the role of ZnO from network modifier to intermediate oxide. The intermediate network forming Zn²⁺ ions would find it more difficult to diffuse and initiate the transformation of Li₃Zn_0.5SiO₄ to Li₂ZnSiO₄. Thus Li₃Zn_0.5SiO₄ is formed instead of Li₂ZnSiO₄ on addition of 2 mol% NiO. Scanning electron microscopy (SEM) and energy dispersive analysis of X-rays (EDAX) measurements at the glass–ceramic-to-metal interface reveal a change in the microstructure commensurate with the changing role of ZnO. Addition of NiO favoured interdiffusion of species at the interface leading to better sealing.