Copper molybdenum sulfide: A novel pseudocapacitive electrode material for electrochemical energy storage device

The ever-growing demand for energy storage devices necessitates the development of novel energy storage materials with high performance. In this work, copper molybdenum sulfide (Cu₂MoS₄) nanostructures were prepared via a one-pot hydrothermal method and examined as an advanced electrode material for supercapacitor. Physico-chemical characterizations such as X-ray diffraction, laser Raman, field emission scanning electron microscope with elemental mapping, and X-ray photoelectron spectroscopy analyses revealed the formation of I-phase Cu₂MoS₄. Electrochemical analysis using cyclic voltammetry (CV), charge-discharge (CD) and electrochemical impedance spectroscopy (EIS) showed the pseudocapacitive nature of charge-storage via ion intercalation/de-intercalation occurring in the Cu₂MoS₄ electrode. The Cu₂MoS₄ electrode delivered a specific capacitance of 127 F g^?1 obtained from the CD measured using a constant current density of 1.5 mA cm^?2. Further, Cu₂MoS₄ symmetric supercapacitor (SSC) device delivered a specific capacitance of 28.25 F g^?1 at a current density of 0.25 mA cm^?2 with excellent rate capability. The device acquired high energy and power density of 3.92 Wh kg^?1 and 1250 W kg^?1, respectively. The Nyquist and Bode analysis further confirmed the pseudocapacitive nature of Cu₂MoS₄ electrodes. The experimental results indicate the potential application of Cu₂MoS₄ nanostructures as a novel electrode material for energy storage devices.     

Conjugate Heat Transfer Analysis for a Finite Thickness Cylinder in a Hypersonic Flow

Prediction of surface heating rates is of prime importance for the hypersonic flow regime. Experimental and conventional computational efforts overlook the heat transfer phenomenon in the solid due to the rigid assumptions involved in the solution methodologies. In order to address this fact, conjugate heat transfer (CHT) studies are carried out using various coupling techniques to examine their implementation abilities. Three types of solution methodologies are adopted, namely, decoupled, strongly coupled, and loosely coupled analysis. This study is also focused on looking into the effect of a hypersonic flow field on wall heat flux for a finite thickness insulating cylinder at moderately large time scales. Increase in wall temperature and decrease in surface heat flux have been noticed using strong and loose coupling techniques with an increase in simulation time. Decoupled fluid and solid domain analysis is found to be useful for typical shock tunnel test durations (～1 ms) while investigations with loose coupling techniques are advisable for time scales corresponding to flight testing (～1 s). Efforts are also made to reason the discrimination in prediction of stagnation point heat flux using conventional computational and experimental analysis.     

Performance Enhancement for Wavy Fin Automotive Radiator Using Optimum PG Brine Based Nanofluids

In this study, optimum propylene glycol (PG) brine‐based nanofluids are being proposed as coolants for a wavy finned automotive radiator. Performance analysis is conducted and compared with conventional Ethylene Glycol (EG) brine and related nanofluids. A 25% PG brine has similar heat transfer characteristics to water at higher operating temperature ranges. The effects on radiator size, weight and cost, engine efficiency and fuel consumtion, and embodied energy saving and environmental impact are discussed as well. Compared to conventional coolant(EG water brine), for the same cooling capacity and radiator size, the coolant requirement and pumping power are reduced significantly by about 25% and 64%, respectively, whereas, for the same cooling capacity and mass flow rate, the radiator size and pumping power is reduced by 4.2% and 25.5%, respectively, with PG brine‐based Ag nanofluids.Furthermore, by using optimum PG brine‐based nanofluids, 3.5% of the embodied energy may be saved, which may yield reductions in radiator cost, engine fuel consumption and environmental costs.     

Efficient Beamformer for Low Mobility Indoor Communication Using Sparse Adaptive Algorithm

Wireless Personal Communications - The proposed beamforming model exploits the underlying sparseness of the adaptive filter as impulse response of wireless channel shows some extent of sparse...     

Rail-to-rail split-output SET tolerant digital gates

Analog Integrated Circuits and Signal Processing - Electronic circuits operating in the radiation intensive environment like space, are subject to a barrage of cosmic particles like neutrons,...     

Effect of Aluminum Filler on Friction and Wear Characteristics of Glass Epoxy Composites

An experimental study was carried out to investigate the dry sliding friction and wear characteristics of woven glass epoxy composites filled with Al particulates sliding against steel using a pin-on-disc tribometer. The glass fiber weight fraction was kept constant at 60 wt% and Al wt% varied as 0, 5, 10, and 15%. The composite was fabricated by a hand lay-up technique followed by light compression molding. Friction and wear behavior under dry sliding condition are presented as a function of sliding speed varying between 1–5 m/s and normal load ranging between 10–40 N. Friction characteristics of composites depend strongly on a combination of filler content, sliding speed and load. Wear loss increases with both sliding speed and load. Incorporation of a smaller amount of Al filler reduces wear loss compared to un-filled glass epoxy composites. An attempt has also been made to observe the distribution of fiber and Al particles in the composite, and to correlate the wear behavior using Scanning Electron Microscopy (SEM) observations.     

Antimicrobial Properties of Nanogold-Imprinted Starch Bionanocomposites

Nanogold-imprinted starch bionanocomposites of various compositions were synthesized by “one-pot reaction” with in situ generation of nanogold. Bionanocomposites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscope and high-resolution transmission electron microscope. The electrical conductivity of nanocomposites was enhanced because of dispersion of nanogold in the starch. Antimicrobial activity of starch was increased due to incorporation of nanogold. The bionanocomposites were resistant towards dilute acid and alkali with little scarification in biodegradable properties. The enhanced thermal, gas barrier and antimicrobial properties may enable the synthesized materials for packaging applications.     

Recovery of metals and other beneficial products from coal fly ash: a sustainable approach for fly ash management

International Journal of Coal Science & Technology - Increasing production and disposal of coal fly ash (CFA) is a matter of serious environment concern. However, CFA contains various...     

Influence of phosphate species on green rust I transformation and local structure and morphology of γ-FeOOH

To clarify the role of phosphate in the formation of corrosion products, the transformation of GRI(Cl⁻) with the addition of phosphate was characterized through XRD, TEM, and solution analysis. Electrochemical analysis showed that the transformation of GRI(Cl⁻) was delayed and the size of the final products, i.e., γ-FeOOH was reduced in the phosphate added case. X-ray absorption spectroscopy indicated that the neighboring Fe–Fe coordination number of FeO₆ octahedral unit in γ-FeOOH was decreased. These effects of phosphate are attributed to its adsorption on GRI(Cl⁻) and nucleated γ-FeOOH that prevented particle growth during oxidation process.     

Dielectric relaxation, conductivity behaviour and magnetic properties of Mg substituted Ni-Li ferrites

The dielectric properties of Mg substituted Ni-Li spinel ferrites synthesized by sol-gel auto combustion process have been studied using impedance measurements in the frequency range from 10 Hz to 10 MHz and in the temperature range from 310 K to 473 K. The effect of frequency, temperature and composition on dielectric constant (?′), dielectric loss (tan δ) and conductivity (σ) has been discussed in terms of hopping of charge carriers between Fe²⁺ and Fe³⁺ ions. The electrical modulus formulism has been employed to study the relaxation dynamics of charge carriers and the results indicate the presence of non-Debye type of relaxation in the present ferrites. Similar values of activation energies for dc conduction (E_dc) and for conductivity relaxation (E_M″) reveal that the mechanisms of electrical conduction and dielectric polarization are same in these ferrites. A single ‘master curve’ for normalized plots of all the modulus isotherms observed for a given composition indicates the temperature independence of dynamical process for charge carriers. The saturation magnetization and coercivity have been calculated from the hysteresis loop measurements and show striking dependence on the composition.