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The present article describes a detailed mathematical investigation of electro-magneto-hydrodynamic dispersion in the pulsatile flow of a Casson viscoplastic fluid in a tube packed with a porous medium. Using appropriate transformations, the model is rendered non-dimensional. Via the generalized dispersion method and finite Hankel transforms, analytical solutions for the solute concentration dispersion and convection coefficients have been obtained. The impact of the Hartmann (magnetic) number, Debye–Hückel(electrokinetic) parameter, Darcy number, and chemical reaction parameter with regard to dispersion phenomena has been studied. The evolution in velocity and concentration profiles are investigated graphically for realistic ranges of the various physical parameters. The present investigation, highlights the dual nature of the Debye–Hückel parameter in the dispersion process. Increment in the lower or higher magnitudes of Debye–Hückel parameter induces or decreases the magnitudes of effective dispersion coefficient, whereas it induces a reverse dual mechanism in the zenith of the average concentration profile. The present simulations are relevant to enhancing the performance of diagnostic tools in biochemical engineering, pumping of intelligent rheological working fluids in biomedicine, and also soft robotics.

Motivated by exploring the fluid dynamics of dual drug delivery systems in biomedicine, a mathematical analysis of the bi-component species transport (convective-diffusion) in rheological blood flow with bulk chemical reaction through a two-dimensional rigid vessel is presented. Two different bulk degradation reaction rates are included for the dual species (pharmacological agents, A, B). An analytical expression for axial velocity is derived using a perturbation method. The decoupled convection-diffusion equations are then analyzed with the Aris – Barton approach. The mean concentration of the species is estimated using the first five concentration moments with the aid of fourth order Hermite polynomials. A finite difference technique based on the Crank Nicholson implicit scheme is employed to handle the pth order moment of the general concentration. The analysis reveals that increasing reversible transfer rate and irreversible bulk degradation result in a reduction in the total mass of the species over time. The mass of both species decreases with an increase in reversible transfer rate, even though the mass of species A depletes faster than the mass of species B. The skewness of the concentration distribution decreases as yield stress increases and the distributions in all scenarios are positively skewed and tend to zero over time, implying that the distribution tends to symmetry over time. The kurtosis decreases over time from positive to negative values and eventually approaches zero. Mean concentration peaks for both species A and B are elevated with increasing yield stress, although magnitudes are significantly higher for species A. With increasing values of the distribution coefficient between two species, mean concentration peaks are elevated for species (component) A whereas they are depleted for species B, although substantially greater magnitudes are computed for species B. Good correlation of the skewness with earlier Newtonian results is achieved. The results provide some useful insight into the bi-component drug transport in smaller vessel pharmacodynamics where hemorheology is important.

This study reports a wet spinning method to spin composite micro-fibres of 2D liquid crystalline graphene oxide (GO) and exfoliated MoS2 nanosheets with very high MoS2 loading. The MoS2 dispersion was found to be isotropic irrespective of solvent type or solute concentration in the dispersion and thus found to be non-spinnable via wet spinning process. The liquid crystallinity of GO induces birefringence in the composite dispersion and enables the spinning of the composite dispersion containing high loading of MoS2 with great flexibility. We were able to spin composite microfibers with 69 wt% MoS2 loading for the first time. The resulting fibres were annealed at high temperature to produce flexible conductive rGO#MoS2 fibres. Scanning electron microscopy (SEM) and Raman analysis strongly suggest homogeneous distribution of MoS2 throughout the fibres. Mechanical properties of the fibres were studied and maximum tensile strength (76.5 MPa) and Young's modulus (13.3 GPa) obtained with 10 wt% MoS2 loading. All solid-state flexible symmetric supercapacitor from these composite fibres was fabricated and the electrochemical performance was studied. The electrochemical study shows high areal capacitance of the produced composite fibres (as high as 282.6 mF cm−2) with good cycling stability (82.5% capacitance retention after 5000 cycles) that indicates high potential of these composite fibres as energy storage system for smart textile of the future.

In this study, N-doped reduced graphene oxide (rGO) wrapped carbon micro fibres (CFs) were synthesized by one-step high temperature pyrolysis method. Free-standing binder-free electrodes of N-doped rGO on CF were fabricated to apply in extended flexible fibrous supercapacitors and sodium-ion batteries (NIBs). The results showed that the attachment of N-doped graphene onto CF led to high electrochemical capacitance properties. The micro-fibre electrodes showed high performance supercapacitor behaviour of 18.7 F cm−3 at a current density of 1 A cm−3 as a flexible solid-state energy storage device. In parallel with the supercapacitance properties, the micro-fibre electrode shows impressive electrochemical performances when evaluated as anode for NIB, delivering a reversible capacity of 400 mAh/g with capacity retention approaching 100% after 100 cycles. The excellent performances are attributed to defects induced by N-doping along with large surface area of hierarchical porous architecture that can facilitate the storage and diffusion of Na+ and prevent the restacking of rGO during cycling. Thus, these N-doped rGO fibrous materials have substantial promise for fabricating extended flexible cable electronics and NIBs with superior strength and performance.

A facile synthesis of three-dimensional (3D) network of copper confined nitrogen-doped graphene (NG)/carbon nanotube (CNT) with high atomic percentage of nitrogen (10.1 at.%) has been reported. The homogenous intercalation of the CNT network in-between the graphene layers decorated with copper nanoparticles take place which inhibits the self-agglomeration within the lattice and enhance the volumetric storage capability. The composite electrode demonstrates exceptionally high specific capacitance of 1250 mA h/g obtained at a current density of 0.1 A/g which is 3.4 times greater than the theoretical capacity of graphite (372 mA h/g). The discharge-charge profiles (from 0.002 to 3 V) with reversible battery capacity exhibit a stable state of the lithium-ion batteries which were observed at high rate capability of 420 mA h/g at a current density of 1 A/g even after 500 cycles. The enhancement of the electrochemical performance could be attributed to the 3D electrically conductive networks of copper confined nitrogen-doped graphene/carbon nanotubes (Cu@[N-Gr/CNT]).

Surface modification of carbon microfibres (CF) represents a promising and challenging alternative for creating multiscale and multifunctional hierarchical lightweight high-performance composite materials. In this study, a low-temperature chemical method is developed to graft layered graphene oxide (GO) directly onto CF through covalent bonding, and the grafting is characterised by SEM, FTIR, Raman and XPS spectroscopy. The GO failure stress (FS) measured using in situ nanomechanical pull-out tests is 36.2% higher than the literature values. Since GO fracture is the only breaking mechanism observed, there exists a strong carbon-carbon covalent bonding at the GO-CF interface indicating that the actual grafting strength (GS) is greater than the FS obtained. This elevated GS can substantially increase the interfacial and impact properties necessary in high performance composites. CF and GO-CF are fabricated to current-collector free ultra-long flexible cable-supercapacitors and their electrochemical properties in gel electrolyte are systematically investigated. GO-CF supercapacitor leads to an electrochemical capacitance of 7.8 F cm−3 and an energy density of 6.93 × 10−4 Wh cm−3 at 0.02 A cm−3. Thus, these grafted materials along with advanced composites have substantial promise in ultra-long flexible cable electronics with superior strengths and performances.

AMR and drug void have caused huge panic today with few thousand death per year. MDR Typhoid was a serious old disease and caused serious health hazard in humen and animals demanding an update on molecular biology of the status on transferable genetic elements. R-plasmids combined in F’-plasmid and the new MDR conjugative plasmids were shown abundant in Sanmonella ranging 70-440kb with similarities. BlaTEM, blaCTX-M, blaOXA, blaNDM mdr genes were abundant in >50 plasmids analyzed and metal resistant gene clusters are predominant in most large plasmids. Among the acetyltransferase all catA1, aacA1 and aac-1b-cr genes were located. Abundant streptomycin phosphotransferases (StrAB) and rarely colistin resistant Mcr-5/9 phosphoethanolamine–lipid A transferase were detected. Altered isomeric dihydropterote synthases (Sul1/2/3) were present giving sulfamethoxazole resistance and dhfr gene frequently associated giving trimethoprim resistance. Metal resistant gene clusters like SilABC (CusABC), PcoAB, RcnA, terABC, and merABCXT etc were found in many Salmonella enterica plasmids. Toxin genes like HipA and virulence genes like spvABD were located in few plasmids increasing virulence and pathogenesis. Drug efflux genes tetA or tetB and OqxB, floR, CmlA were frequent where as QepA and EamA genes were rarely seen. Thus, Salmonella metal resistant genes combined with antibiotic resistant genes has tried to overcome the both toxic antibiotics and metalions causing Typhoid AMR. Such acquisition spreads salmoniasis in the live stocks (pig, cow, chicken) where toxic soil and water dominate increasing chance of MDR typhoid in human.

Nickel nanoparticles supported on nitrogen doped graphene (Ni−NGr) as highly efficient electrocatalyst were synthesized via controlled thermal annealing using a mixture of graphene oxide, nickel nitrate and uric acid. The synthesized Ni−NGr catalyst presented excellent electrocatalytic performance for ethanol, glucose and glycerol oxidation, stemming from the synergistic effects of nickel and N-graphene. The electrocatalytic activity was enhanced by the high surface area and nitrogen-based active sites of pyridinic and graphitic N in doped graphene. These N-moieties enhanced the accessibility of active sites while preventing agglomeration of nickel nanoparticles on the doped graphene surface. The hybrid electrocatalyst performances were significantly improved and are suited for electrooxidation application in fuel cells.

A three-dimensional nanostructured nitrogen-doped graphene/carbon nanotube composite has been synthesized via a thermal annealing process, using the high surface attachment properties of uric acid (solid nitrogen precursor) with graphene oxide and oxidized multiwalled carbon nanotube. In the synthesis procedures, the attachment of uric acid to graphene oxide surfaces and the oxidized multiwalled carbon nanotubes via hydrogen bonding and electrostatic forces in the solution leads to a lamellar nanostructure during thermal annealing by the proper insertion of carbon nanotubes in graphene layers with nitrogen doping. The resultant composite has good atomic percentage of N (11.2 at. %) and shows superior electrochemical energy storage and conversion properties compared with nitrogen-doped graphene only and physically mixed nitrogen-doped graphene and nitrogen-doped carbon nanotube samples. The composite exhibits high gravimetric and volumetric capacitance (324 F g-1 at a current density of 1 A g-1) as electrode in solid-state supercapacitors, superior capacitive deionization (440 F g-1 at a current density of 1 A g-1) in 1 M sodium chloride solution, and as high-performance anode in lithium-ion batteries (1150 mAh g-1 at 0.1 A g-1) with long-term cycling stability. In addition, the composite demonstrates efficient metal-free bifunctional electrocatalysis toward the oxygen reduction and evolution reactions, comparable with the commercial electrocatalysts.

A multifunctional nano-heterostructured electrocatalyst of transition metal/metal oxide (nickel/nickel oxide) embedded on nitrogen-doped graphene is reported. The hybrid composite of N-doped graphene nanosheets with a high atomic percentage of nitrogen (8.2 at%) and embedded with highly distributed nickel/nickel oxide nanoparticles inside the graphene layers is synthesized by a one pot thermal annealing process. The resultant composite demonstrates excellent electrocatalytic activity utilizing the superior electrocatalytic properties of nickel/nickel oxide nanoparticles supported on nitrogen-doped graphene. The hybrid exhibits efficient oxygen reduction reaction (ORR) properties comparable with state-of-the-art electrode Pt/C with a four-electron transfer pathway and superior oxygen evolution reaction (OER) compared to the state-of-the-art electrode for the OER, Ru/C. Alternatively, this composite acts as an excellent electrode material for the hydrogen evolution reaction (HER) both in acidic and alkaline media. Nevertheless, this composite facilitates the hydrogen peroxide oxidation reaction (HPOR) in the presence of hydrogen peroxide, which is crucial for developing reversible fuel cells and fuel cells with liquid oxidant.

A free-standing, 3D, macro/microstructured atomic-cobalt/cobalt-oxide–reduced-graphene-oxide (Co/Co3O4-Gr) composite has been developed for complete water splitting. The self-assembled porous morphology associated with the metal/metal oxide active sites makes the whole surface of the electrode conducive toward catalyzing hydrogen and oxygen evolution in alkaline media at a low onset potential. The liquid-crystal-mediated free-standing electrocatalyst shows oxygen evolution at the onset potential of 1.38 V and at the potential of 1.66 V for a current density of 10 mA cm−2. These potentials are comparable to the corresponding values for Ru/C (1.46 and 1.62 V, respectively). In addition, the promising hydrogen evolution performance of our composite compared to Pt/C in alkaline media makes it an efficient bifunctional electrocatalyst for comprehensive water splitting, as well as provides guidance for future electrochemical energy material technologies.

A non-enzymatic sensing platform was developed for detecting glucose and hydrogen peroxide using nitrogen doped graphene decorated with copper-nickel nanoparticles. The synthesized CuNi-NGr composite presented excellent electrocatalytic interaction with glucose and hydrogen peroxide owing to the synergistic effect of copper, nickel and N-graphene. The enhanced performance of the active materials was due to the presence of nitrogen based active sites with high contents in pyridinic and graphitic N as well as the electrocatalytic activity of distributed copper and nickel nanoparticles on graphene. Amperometric analysis showed that the sensitivity of CuNi-NGr based electrode was 7143 μA.mM−1.cm−2 at low (0.01 μM to 1 mM), and 1030 μA.mM−1.cm−2 at high concentrations (2 to 20 mM) of glucose. The detection responses had corresponding linear ranges as functions of concentration with limit of detection (LOD): 10 nM at S/N = 3. For hydrogen peroxide, the fabricated electrode showed detection sensitivity of 954 μA.mM−1.cm−2 with LOD of 10 μM (S/N = 3) and linear response within 0.01 to 1 mM. On testing, the electrode displayed excellent reproducibility, stability and selectivity for detecting glucose and H2O2 simultaneously in aqueous electrolytes. The sensor was shown to be effective in analyzing glucose and H2O2 present in human urine with excellent recovery.