We study the drag resistivity numerically for charge carriers in a specially separated electron-electron (e-e) bilayer system for both the symmetric and asymmetric case in weak interaction and ...Boltzmann regime. Interaction in Coulomb drag effect is based on Coulomb interaction in a specially separated bilayer systems. Random phase approximation (RPA) method is used to find the drag resistivity. Simply RPA method is a reliable method for high-density regime where exchange and correlation effects do not impact too much. On lowering the density, the exchange and correlation effects are significant which are included by suggesting the local field correction (LFC) in effective interlayer interactions. The drag resistivity is noticed improvement on employing the LFC. Impact of exchange and correlation based LFC increase on increasing the temperature and decreasing the concentration. Predictable behaviour is shown by the dependency of drag resistivity on temperature, density, interlayer spacing, and dielectric constant.
We present a numerical calculation for the drag resistivity of charge carriers interaction in coupled layer system separated by a barrier. Analytical expressions of non-linear susceptibility function ...and effective interlayer Coulomb interaction have been shown for non homogeneous dielectric environment at low temperature and low frequency regime. The system is studied within the model of random phase approximation (RPA) and taking into account the static local field correction (LFC). We employ Hubbard approximations (HA) and self consistent STLS approximations based LFC for obtaining the results, where LFC includes the exchange and correlation effects. Exchange and correlation effects enhanced the drag resistivity and the net screening. Another important quantity is the local form factors (LFF), which is the function of the bare inter- and intra-layer potential of the dielectric media. LFF for a multi-layer system is derived from the Poisson equation solution.
•We have measured the drag resistivity in 2D-GaAs bilayer system for weakly interacting regime.•Analytical expressions of response function are used in Boltzmann regime and bare Coulomb interaction for non-homogeneous dielectric environment which make the system interested and different compare to others.•RPA method is used to evaluate the results with including exchange and correlation effects. Exchange and correlation effects are considered in the calculation using Hubbard and STLS approximations in dielectric function.•The Local Form Factor (LFF) are obtained from the solution of the Poisson equation of a three-layer dielectric medium.•Drag resistivity dependency is measured numerically with respect to temperature T and density n and compared to other 2DES.
In green energy generation, recently Hydroelectric cell (HEC) by dissociating the water molecules at room temperature has taken a big stride among other alternative green energy sources. In this ...work, another unique novel material Ni substituted lithium ferrite (LNFO) for the fabrication of hydroelectric cell to generate green electricity has been reported. Oxygen deficient nanoporous LNFO has been synthesised by the Solid-State reaction method. Special processing steps were taken to control oxygen defect’s concentration in the ferrite by varying pre-sintering temperature during its synthesis to deliver more power output. Phase formation of nickel substituted lithium ferrite has been confirmed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The porous microstructure of LNFO has been analysed by Field-emission scanning electron microscope (FESEM) micrographs, BET and DFT techniques. The presence of defects and decrease in their concentration with the increase in pre-sintering temperature has been confirmed by analysing X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) measurements. Hydroelectric cell fabricated using LNFO pellets pre-sintered at 750 °C and 800 °C, delivered output current densities of 3.8 mA/cm2 and 3.6 mA/cm2 respectively. The decrease in output current is attributed to reduction in defect concentration as confirmed by PL and XPS spectrum. Generated current densities are two times higher than reported in lithium substituted magnesium ferrite based hydroelectric cell (1.7 mA/cm2).
•Nanoporous nickel substituted lithium ferrite (Li0.3Ni0.4Fe2.3O4) has been used for fabrication of hydroelectric cell.•Variation in output current of Hydroelectric Cell as function of pre-sintering temperature conditions has been studied.•We obtained two times higher current densities as compared to earlier reported Mg0.8Li0.2Fe2O4 based hydroelectric cell.•Effect of defects, which acts as active sites to dissociate water, on output of Hydroelectric cell has been studied.
Drag resistivity mediated by Coulomb interaction is a transport phenomenon in a specially separated bilayer systems. The drag resistivity is numerically analysed for both the n- and p-type charge ...carriers between the bilayer-graphene and a GaAs layer, with an insulating barrier by using random phase approximation (RPA). The RPA method does not include exchange and correlation effects, which are included by assuming the local field correction (LFC) in effective interactions. Because of the LFC effects, the drag resistivity is found enhanced compared to the measured results of RPA. The present bilayer system shows a comparison between effect of electron–electron (e–e) repulsive and electron–hole (e–h) attractive interactions in Boltzmann regime for low temperature limit. Different masses of electrons and holes in GaAs layer are analysed, and drag resistivity is increased on increasing the effective mass of the charge carriers. The dependency of drag resistivity on temperature, concentration, interlayer separation, width of the drag layer and dielectric constant of barrier shows a consistent behaviour.
The Gibbs phenomenon describes oscillations of small or large amplitudes that occur, when a signal with steep gradients or noise components is approximated. Such interruptions can degrade the quality ...of desired signal. Reduction of such oscillations is an essential task to extract vital information from the desired signal. This paper, therefore, presents the Chebyshev spectral method (CSM) that is combined with two novel concepts to reduce the influence of oscillatory structures. The first notion uses a thresholding approach to estimate true expansion coefficients in a noisy environment, while the second concept introduces a new smoothing function. The basic framework of the proposed concept is to introduce an additional threshold procedure into pre-existing Chebyshev collocation method to handle the fluctuations of noise interferences. Moreover, the CSM is the global-behaviour approximation based on the points of an entire domain, which allows for high-order convergence to be recovered. The method is implemented for sharp gradient-contained function and to a signal that has been distorted by noise. Through computational experiments, efficiency of the proposed method is verified graphically and numerically. Signal-to-noise ratio of 37.4810 dB is achieved with corresponding mean square error about 1.79e−04. The percentage root-mean-square difference (PRD) and maximum error are obtained as 1.3402% and 0.0399, respectively.
In this study, TiO2 nanoparticles are decorated on multi-walled carbon nanotubes (MWCNTs) by exploitation of opposite zeta potential of MWCNTs and TiO2 nanoparticles without degrading the hexagonal ...interatomic structure of MWCNT and generated new MWCNT/TiO2 hybrid nanofiller (MT hybrid nanofiller). The newly obtained MT hybrid nanofiller (from 0.25 wt% to 1.50 wt%) is loaded in crosslinking epoxy matrix to understand the multiphase nanocomposite in terms of mechanical performance under various stresses (storage modulus, loss modulus, tensile strength and modulus). The decoration of TiO2 nanoparticles on MWCNTs changes the fracture mechanism in the mirror zone and generates a new fracture surface, which changes the behavior of multiphase nanocomposite under various types of stresses.
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•MWCNT/TiO2 hybrid nanofillers play a significant role in transfer of applied stress from matrix to nanofiller.•MWCNT/TiO2 hybrid nanofillers change the fracture mechanism in the mirror zone.•Mechanical properties were strongly influenced by dispersion and interfacial interaction.
Discretization-based spectral approximation methods provide spectrally accurate reconstruction of an analytic function. The expansion of non-smooth functions is contaminated by high frequency ...non-diminishing oscillations near discontinuity points, and this behaviour is named as Gibbs phenomenon. This problem can be well resolved by well-chosen post-processing technique, and one possible choice is spectral filtering. In this paper, a comparison scenario of adaptive spectral filtering for resolution of Gibbs phenomenon is presented. Several spectral filter functions are compared using Chebyshev collocation and Legendre collocation spectral methods, in terms of pointwise and
L
2
normed-wise convergence analysis of computed filtered approximations.
Multiferroic is the future of the next generation memory devices; because of its advantages over the single-phase ferroelectric and ferromagnetic memory systems. In conventional ferroelectric memory ...system fatigue effect lowers the storage capacity. Other side high magnetic energy is essential for writing the data in ferromagnetic-based memory system. Considering these facets and taking environmental issue in the account we developed lead-free Na
0.5
Bi
0.5
TiO
3
(NBT)–CoFe
2
O
4
(CFO) multiferroic system via two wet chemical methods. To check the feasibility of the system for device application various physical measurements were carried out. The structural analyses have been done by XRD, FTIR and FESEM which confirm the coexistence of bi-phase in these composites. The dense microstructure was observed for composite sample with highest CFO concentration. In comparison to pure ferrite phase, the composite exhibit low leakage current density, high dielectric constant with low dielectric losses. Interestingly, the CFO affected the phase transition temperature of the NBT as evidenced by the dielectric behaviour as a function of temperature. Also, multiferroic studies were influenced by the content of CFO/NBT phases in composite system. Furthermore, the highest value of ME coupling (~ 64 μV/Oe-cm) was observed for the 50CFO/50NBT composite system.
Pyridoxine‐dependent epilepsy (PDE‐ALDH7A1) is an autosomal recessive condition due to a deficiency of α‐aminoadipic semialdehyde dehydrogenase, which is a key enzyme in lysine oxidation. PDE‐ALDH7A1 ...is a developmental and epileptic encephalopathy that was historically and empirically treated with pharmacologic doses of pyridoxine. Despite adequate seizure control, most patients with PDE‐ALDH7A1 were reported to have developmental delay and intellectual disability. To improve outcome, a lysine‐restricted diet and competitive inhibition of lysine transport through the use of pharmacologic doses of arginine have been recommended as an adjunct therapy. These lysine‐reduction therapies have resulted in improved biochemical parameters and cognitive development in many but not all patients. The goal of these consensus guidelines is to re‐evaluate and update the two previously published recommendations for diagnosis, treatment, and follow‐up of patients with PDE‐ALDH7A1. Members of the International PDE Consortium initiated evidence and consensus‐based process to review previous recommendations, new research findings, and relevant clinical aspects of PDE‐ALDH7A1. The guideline development group included pediatric neurologists, biochemical geneticists, clinical geneticists, laboratory scientists, and metabolic dieticians representing 29 institutions from 16 countries. Consensus guidelines for the diagnosis and management of patients with PDE‐ALDH7A1 are provided.
•Report of twenty nine cases of CNS demyelination with close temporal association to COVID-19 vaccination.•Clinical presentation is heterogenous, including myelitis, optic neuritis, ADEM, brainstem ...demyelination and multiaxial involvement.•Most prevalent antibody in postvaccinial cases is the antibody against MOG antigen.•As compared to the controls, postvaccinial demyelination cases have significantly higher encephalopathy features, CSF pleocytosis and raised CSF protein.
ChAdOx1-S (Covishield™/Vaxzervria, AstraZeneca) and BBV152 (Covaxin) SARS-CoV-2 vaccines are proven to be safe and effective, but rare complications have been reported.
To describe reports of central nervous system (CNS) demyelination following ChAdOx1-S and BBV152 vaccinations.
We report 29 (17 female; mean 38 years) cases of CNS demyelination; twenty-seven occurred in temporal association with ChAdOx1-S vaccine; two in association with BBV152 vaccine. Eleven patients had presentation with myelitis, six patients developed optic neuritis, five had acute demyelinating encephalomyelitis, three presented with brainstem demyelination, and four had multiaxial involvement. Myelin oligodendrocyte glycoprotein (MOG) antibodies were positive in ten patients. One patient with ADEM and tumefactive demyelinating lesions died after a prolonged intensive care unit stay and superimposed infection. As compared to the control group (87); the postvaccinial cases were found to have a significantly higher mean age, presence of encephalopathy (p value:0.0007), CSF pleocytosis (p value: 0.0094) and raised CSF protein (p value: 0.0062).
It is difficult to establish a causal relationship between vaccination and neurological adverse events such as demyelination. The temporal association with the vaccination and the presence of MOG antibodies raises the possibility of an immunogenic process triggered by the vaccine in susceptible individuals.
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