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The information engine is a feedback mechanism that extorts work from a single heat bath using the mutual information earned during the measurement. We consider an overdamped active Ornstein–Uhlenbeck particle trapped in a 1D harmonic oscillator. The particle experiences fluctuations from an inherent thermal bath with a diffusion coefficient (D) and an active reservoir, with characteristic correlation time (τa) and strength (Da). We design a feedback-driven active Brownian information engine (ABIE) and analyze its best performance criteria. The optimal functioning criteria, the information gained during measurement, and the excess output work are reliant on the dispersion of the steady-state distribution of the particle's position. The extent of enhanced performance of such ABIE depends on the relative values of two underlying time scales of the process, namely, thermal relaxation time (τr) and the characteristic correlation time (τa). In the limit of τa/τr → 0, one can achieve the upper bound on colossal work extraction as ∼ 0.202 γ (D + D a ) (γ is the friction coefficient). The excess amount of extracted work reduces and converges to its passive counterpart (∼ 0.202 γ D) in the limit of τa/τr → high. Interestingly, when τa/τr = 1, half the upper bound of excess work is achieved irrespective of the strength of either reservoirs, thermal or active. Finally, we look into the average displacement of active Brownian particles in each feedback cycle, which surpasses its thermal analog due to the broader marginal probability distribution. [ABSTRACT FROM AUTHOR]

"Gating" is a widely observed phenomenon in biochemistry that describes the transition between the activated (or open) and deactivated (or closed) states of an ion-channel, which makes transport through that channel highly selective. In general, gating is a mechanism that imposes an additional restriction on a transport, as the process ends only when the "gate" is open and continues otherwise. When diffusion occurs in the presence of a constant bias to a gated target, i.e., to a target that switches between an open and a closed state, the dynamics essentially slow down compared to ungated drift-diffusion, resulting in an increase in the mean completion time, ⟨TG⟩ > ⟨T⟩, where T denotes the random time of transport and G indicates gating. In this work, we utilize stochastic resetting as an external protocol to counterbalance the delay due to gating. We consider a particle in the positive semi-infinite space that undergoes drift-diffusion in the presence of a stochastically gated target at the origin and is moreover subjected to rate-limiting resetting dynamics. Calculating the minimal mean completion time ⟨ T r ⋆ G ⟩ rendered by an optimal resetting rate r⋆ for this exactly solvable system, we construct a phase diagram that owns three distinct phases: (i) where resetting can make gated drift-diffusion faster even compared to the original ungated process, ⟨ T r ⋆ G ⟩ < ⟨ T ⟩ < ⟨ T G ⟩ , (ii) where resetting still expedites gated drift-diffusion but not beyond the original ungated process, ⟨ T ⟩ ≤ ⟨ T r ⋆ G ⟩ < ⟨ T G ⟩ , and (iii) where resetting fails to expedite gated drift-diffusion, ⟨ T ⟩ < ⟨ T G ⟩ ≤ ⟨ T r ⋆ G ⟩. We also highlight various non-trivial behaviors of the completion time as the resetting rate, gating parameters, and geometry of the set-up are carefully ramified. Gated drift-diffusion aptly models various stochastic processes such as chemical reactions that exclusively take place in certain activated states of the reactants. Our work predicts the conditions under which stochastic resetting can act as a useful strategy to enhance the rate of such processes without compromising their selectivity. [ABSTRACT FROM AUTHOR]

Biological neurons are electro-mechanical systems, where the generation and propagation of an action potential are coupled to the generation and transmission of an acoustic wave. Neuristors, such as VO2, characterized by insulator-metal transition (IMT) and negative differential resistance, can be engineered as self-oscillators, which are good approximations of biological neurons in the domain of electrical signals. In this study, we show that these self-oscillators are coupled electro-opto-mechanical systems, with better energy conversion coefficients than the conventional electro-mechanical or electro-optical materials. This is due to the significant contrast in the material's resistance, optical refractive index, and density across the induced temperature range in a Joule heating driven IMT. We carried out laser interferometry to measure the opto-mechanical response while simultaneously driving the devices electrically into self-oscillations of different kinds. We analyzed films of various thicknesses, engineered device geometry, and performed analytical modeling to decouple the effects of refractive index change vis-à-vis mechanical strain in the interferometry signal. We show that the effective piezoelectric coefficient (d13*) for our neuristor devices is 660 ± 20 pm/V, with a 31% internal energy conversion efficiency, making them viable alternatives to Pb-based piezoelectrics for MEMS applications. Furthermore, we show that the effective electro-optic coefficient (r13*) is ∼22 nm/V, which is much larger than that in thin-film and bulk Pockels materials. [ABSTRACT FROM AUTHOR]

We design a geometric Brownian information engine by considering overdamped Brownian particles inside a two-dimensional monolobal confinement with irregular width along the transport direction. Under such detention, particles experience an effective entropic potential which has a logarithmic form. We employ a feedback control protocol as an outcome of error-free position measurement. The protocol comprises three stages: measurement, feedback, and relaxation. We reposition the center of the confinement to the measurement distance (xp) instantaneously when the position of the trapped particle crosses xp for the first time. Then, the particle is allowed for thermal relaxation. We calculate the extractable work, total information, and unavailable information associated with the feedback control using this equilibrium probability distribution function. We find the exact analytical value of the upper bound of extractable work as ( 5 3 − 2 l n 2) k B T. We introduce a constant force G downward to the transverse coordinate (y). A change in G alters the effective potential of the system and tunes the relative dominance of entropic and energetic contributions in it. The upper bound of the achievable work shows a crossover from ( 5 3 − 2 l n 2) k B T to 1 2 k B T when the system changes from an entropy-dominated regime to an energy-dominated one. Compared to an energetic analog, the loss of information during the relaxation process is higher in the entropy-dominated region, which accredits the less value in achievable work. Theoretical predictions are in good agreement with the Langevin dynamics simulation studies. [ABSTRACT FROM AUTHOR]

This article aims to manifest a new way of the utilization of renewable resources in a distribution network. Solar power acts as a source of excitation in the field winding of a separately excited biogas DC generator for the generation of DC power. The amount of DC power required by the generator's field winding is supplied by harnessing a minimum amount of solar energy from a solar photovoltaic (solar PV) for the operation of the bio-power generator of a rated capacity of 5 kW. It is observed, that the availability of 5% peak solar power can be utilized for full excitation of the generator and, it is observed that the full load demand at the time around 16:00 pm can be catered only by the bio-generator. In this work, it has been acknowledged that solar power can be effectively used in low insolation. In addition, it has been revealed, no auxiliary power source is needed for the operation of the generator approximately, 330.22 W of DC power is required by the field winding for full excitation of the DC generator. The present research developed a unique way of power management strategy, which can mitigate the delicate problems in a conventional distribution system. [ABSTRACT FROM AUTHOR]

In this article, a novel compact dual‐band uniform circular array (UCA) is proposed to generate the conical‐shaped orbital angular momentum (OAM) beam with high azimuthal symmetry for vehicular communication. Most antenna designs proposed in the past for obtaining conical‐shaped radiation patterns have complex structures and are very expensive. However, the generation of conical‐shaped patterns by an OAM antenna provides simplicity in the structural realization and is compact for integrating with transceiver circuits. By selecting circularly polarized (CP) patches as array elements of a UCA, conical‐shaped OAM beams can be generated. The proposed UCA consists of a simple feed network with eight dual‐band CP elements. The required phase delay for generating OAM beam (l $l$ = +1 mode) is obtained by rotating the CP elements 45∘ $4{5}^{\circ }$ in clock wise direction. The UCA is 150 mm × $\times $ 140 mm in size, fabricated on a FR4 substrate, and experimentally tested. The measured results confirm that the generated OAM beam has conical‐shaped radiation patterns at 5.3 and 5.77 GHz. The generated OAM beam has a peak gain of 10 dBi with high mode purity and a divergence angle of ±20∘ $\pm 2{0}^{\circ }$ in both simulated and measured findings. [ABSTRACT FROM AUTHOR]

A water-stable and structurally-characterized earth-abundant copper(II) complex, [Cu(dpa)2(N3)]Cl·4H2O, containing an N,N-chelator (dpa = 2,2′-dipyridylamine) and an ancillary ligand (N3− = azide ion) was synthesized and evaluated for electrocatalytic H2 production activity in water using acetic acid as a proton source. Crystal engineering approach revealed the presence of multiple lattice water molecules and a chloride ion in the secondary coordination zone of the distorted square pyramidal copper(II) complex forming an 8-membered tetrameric water cluster and, subsequently, an 11-membered hexameric water cluster in a repetitive mode in association with a water-chloride cluster, leading to a beautiful long-range supramolecular framework involving the chains of a copper(II) complex. The copper catalyst exhibited excellent hydrogen generation activity for the electrochemical proton reduction in acidic water with a rate of 49.81 s−1. A Faradic efficiency of 71% was derived from controlled potential electrolysis (CPE) with [Cu(dpa)2(N3)]+ at −1.25 V vs. Ag/AgCl for 3 h using a glassy carbon electrode ensuring a high turnover number of 41.96 and the desired durability of the molecular electrocatalyst under electrochemical conditions. Further, electrochemical, spectroscopic, and computational studies propose the proton-coupled reduction mechanism for the hydrogen evolution where endo conformational Hδ+⋯Hδ− coupling effectively releases molecular hydrogen. [ABSTRACT FROM AUTHOR]

This work examines the effect of dark matter haloes on the fate of bar-driven escaping patterns in disc galaxies. In this study, a three-dimensional gravitational model with a strong bar profile has been considered and examined separately for the following dark halo profiles: NFW and oblate. These profiles are chosen to model massive and low-mass disc galaxies, respectively. In both cases, a bar-driven escape mechanism has been identified near the saddle points of the phase space, which correspond to the bar ends. This bar-driven escaping motion has been analysed via orbital and Poincaré surface section maps. Moreover, with a choice of initial condition in the vicinity of escape saddles, the variation of its maximal Lyapunov exponent value against the dark halo parameters such as mass, size, circular velocity and nature has been studied. This helps to determine the sensitivity of the bar-driven escaping patterns to the dark halo parameters. Our results state that NFW dark haloes support the formation of bar-driven grand design spiral arms (as we have seen in massive disc galaxies) only if there is an excess energy generation source other than the baryonic feedback generated due to the accretion of the central supermassive black hole. In this regard, active galaxies might be one of the potential contenders where NFW profiles may be a better fit for modelling dark haloes. On the other hand, oblate dark haloes support the formation of bar-driven less prominent spiral arms in low-mass disc galaxies like S0, ultra-compact dwarfs, etc. [ABSTRACT FROM AUTHOR]

We numerically investigate the mean exit time of an inertial active Brownian particle from a circular cavity with single or multiple exit windows. Our simulation results witness distinct escape mechanisms depending on the relative amplitudes of the thermal length and self-propulsion length compared to the cavity and pore sizes. For exceedingly large self-propulsion lengths, overdamped active particles diffuse on the cavity surface, and rotational dynamics solely governs the exit process. On the other hand, the escape kinetics of a very weakly damped active particle is largely dictated by bouncing effects on the cavity walls irrespective of the amplitude of self-propulsion persistence lengths. We show that the exit rate can be maximized for an optimal self-propulsion persistence length, which depends on the damping strength, self-propulsion velocity, and cavity size. However, the optimal persistence length is insensitive to the opening windows' size, number, and arrangement. Numerical results have been interpreted analytically based on qualitative arguments. The present analysis aims at understanding the transport controlling mechanism of active matter in confined structures. [ABSTRACT FROM AUTHOR]

We present a theoretical model to study the origin of chiral symmetry breaking of a racemic mixture of optically active biomolecules. We consider a collection of Brownian particles, which can stay in any of the three possible isomeric states: one achiral and two enantiomers. Isomers are undergoing self-regulatory reaction along with chiral inhibition and achiral decay processes. The reaction rates of the isomeric states are guided by their neighbors as well as the thermal fluctuations of the system. We find that an alteration in the relative dominance of self-regulation, chiral inhibition, and achiral decay processes breaks the chiral symmetry of the system, which is either partial or complete. This results in four different asymmetric population states, viz., three-isomer coexistence, enantiomeric coexistence, chiral–achiral coexistence, and homochiral state. A change in the reaction condition induces nonequilibrium transition among these states. We also report that a fast stochastic self-regulation and a slow chiral inhibition and achiral decay process along with a threshold population of interacting neighbors suffice for the requisite for transition toward a completely symmetry broken state, i.e., homochirality. [ABSTRACT FROM AUTHOR]

Atomically-abrupt interfaces in transition metal oxide (TMO) heterostructures could host a variety of exotic condensed matter phases that may not be found in the bulk materials at equilibrium. A critical step in the development of such atomically-sharp interfaces is the deposition of atomically-smooth TMO thin films. Optimized deposition conditions exist for the growth of perovskite oxides. However, the deposition of rutile oxides, such as VO 2 , with atomic-layer precision has been challenging. In this work, we used pulsed laser deposition to grow atomically-smooth VO 2 thin films on rutile TiO 2 (101) substrates. We show that an optimal substrate preparation procedure followed by the deposition of VO 2 films at a temperature conducive for step-flow growth mode is essential for achieving atomically-smooth VO 2 films. The films deposited at optimal substrate temperatures show a step and terrace structure of the underlying TiO 2 substrate. At lower deposition temperatures, there is a transition to a mixed growth mode comprised of island growth and layer-by-layer growth modes. VO 2 films deposited at optimal substrate temperatures undergo a sharp metal to insulator transition, similar to that observed in bulk VO 2 , but at a transition temperature of ∼ 325 K with ∼ 10 3 times increase in resistance. [ABSTRACT FROM AUTHOR]

A structurally characterized porous Ag(I)-molecular cage AgMOC and a Cu(II)-coordination polymer CuCP with a pre-synthesized ligand 1,3-bis(((E)-2-methoxybenzylidene)amino)propan-2-ol and its parental amine with thiocyanate are reported to harness electrical mobility-driven hydrogen evolution activity. Porosity-induced electrically conductive AgMOC emerges as a better electrocatalyst with a Tafel slope of 104 mV per decade over Cu(II)-polymer's slope of 128 mV per decade. The electrochemical stability and durability of the designed electrocatalysts in harnessing the HER activity are also examined under experimental conditions. [ABSTRACT FROM AUTHOR]

The objective of this study was to obtain insight into the synthesis and structural changes of organo-montmorillonite (OMT) by tailoring montmorillonite (MMT) with the help of a quaternary ammonium salt. The OMT was prepared as a precursor to the development of enhanced asphalt rubber (AR) product. The dimethyldioctadecylammonium chloride (DDAC) provided the required thermodynamic driving force for changing the polarity of hydrophilic MMT to organophilic when both materials were mixed at 80°C under constant stirring for about 12 h. The newly synthesized OMT and base MMT were thoroughly characterized by using particle size analyzer, zeta potential, infrared (IR) spectroscopy, powder X-ray diffraction, and scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) measurements encompassing 20,936 data points. The SEM images of OMT depicted the grafted fibrils of long-chain aliphatic hydrocarbons. At the same time, EDX indicated the exchange of sodium and magnesium cations with carbon and nitrogen of the DDAC. Comparison of the IR spectra for reactants and OMT powders concluded that water molecules were removed and methyl/methylene functional groups were inserted in the OMT. The 100 basal reflections of OMT were 1.894 nm, while that of untreated MMT was 1.522 nm, which corroborated the intercalation of the long alkyl chains of the DDAC, a cationic surfactant in the OMT. The study established a simple method for the preparation of OMT to be used as an AR modifier for roadway applications supporting the utilization of nanoclay material in resolving storage stability issues and enhancing properties of recycled rubber–based asphalt products. [ABSTRACT FROM AUTHOR]

The continuous heating of the Earth’s surface and aerosphere causes global warming. Recent developments predict that at the end of the twenty-first century, with 3 °C on average global warming will yield a regional augmentation in the probability of the abnormally large precipitation accumulation in a single downpour event. We examine this issue using a stochastic climate model and provide a theoretical scheme to the increased possibility of cloudburst in a single rainfall event. We find that implementing a permanent upper cut-off in column integrated water vapour or an asymmetric stochastic resetting can reduce the abnormally high accumulation probability of such rainstorms. We report that an optimum upper limit of column integrated water vapour in the atmosphere ascertain the decrease in the heavy precipitation-accumulation. The presence of such a perpetual upper ceiling in the moisture content is energy exorbitant and can significantly affect the mean downpour. A careful choice of the system parameters ensures the decrease in mean accumulation size within a ten per cent tolerance limit. We introduce an asymmetric stochastic resetting to the amount of column integrated water vapour at its upper threshold to recompense the energy cost. We perceive that an adaptive restart rate is efficient enough to reduce the probability of targeted precipitation accumulation to the desired extent. [ABSTRACT FROM AUTHOR]

Abstract Graphene-oxide/alumina (GO/Al2O3) nanocomposite was synthesized and applied for the removal of phosphate from water through adsorption. Various parameters like the influence of adsorbent dose, adsorption time, solution pH, and initial phosphate concentration on the phosphate removal capacity were examined. It was observed that the second-order kinetics model fitted better compare to the first-order kinetics. The adsorption isotherm was best fitted with Langmuir isotherm compare to Freundlich isotherm. The GO@Al2O3 nanocomposite showed maximum phosphate adsorption capacity 33.2 mg/g at pH 6 and room temperature 30 °C.The new phosphate adsorbents can be produced in a variety of structures using a simple technique and are likely to be applied to industrial applications in phosphate contaminated wastewater management. [ABSTRACT FROM AUTHOR]

This article presents the realistic initial design studies of a 300-GHz, 1-MW, conventional-cavity gyrotron for its probable application in the next-generation thermonuclear fusion reactors. Keeping the design goals, parameters, and constraints in view, the very high-order TE49,18 mode is chosen as the operating mode after a careful mode-selection calculation considering realistic ohmic cavity losses. After mode selection and mode competition studies, the cold-cavity design and initial design of a triode-type magnetron injection gun (T-MIG) and a gyrotron magnet are carried out and an electron beam radius of 8.11 mm is obtained with 2.4% velocity spread. Furthermore, investigation on RF behavior of the cavity is performed with the T-MIG beam parameters. By varying the nominal beam parameters, single-mode self-consistent calculations are conducted and achieved the desired output power. Then, multimode time-dependent self-consistent calculations are carried out before and after space-charge neutralization (SCN) with realistic velocity spread (up to 6%) and different beam radii for the assessment of the start-up scenario. Before SCN without velocity spread, the beam voltage is depressed to 70.08 kV and 0.72-MW output power is obtained, whereas with velocity spread (6%), 0.69-MW output power is obtained with 8.11 mm of beam radius. After 60% of SCN in the start-up scenario with velocity spread (6%), the beam voltage increases to 74.83 kV, and thereby, an output power of 0.91 MW is obtained. [ABSTRACT FROM AUTHOR]

We report a three dimensional Langevin dynamics simulation of a uniformly charged flexible polyelectrolyte chain, translocating through an asymmetric narrow channel with periodically varying cross sections under the influence of a periodic external electric field. When reflection symmetry of the channel is broken, a rectification effect is observed with a favored direction for the chain translocation. For a given volume of the channel unit and polymer length, the rectification occurs below a threshold frequency of the external periodic driving force. We have also observed that the extent of the rectification varies non-monotonically with increasing molecular weight and the strength of geometric asymmetry of the channel. Observed non-monotonicity of the rectification performance has been interpreted in terms of a competition between two effects arising from the channel asymmetry and change in conformational entropy. An analytical model is presented with predictions consistent with the simulation results. [ABSTRACT FROM AUTHOR]

We have studied the occurrence of stochastic resonance when a flexible polymer chain undergoes a single-file translocation through a nano-pore separating two spherical cavities, under a time-periodic external driving force. The translocation of the chain is controlled by a free energy barrier determined by chain length, pore length, pore-polymer interaction, and confinement inside the donor and receiver cavities. The external driving force is characterized by a frequency and amplitude. By combining the Fokker-Planck formalism for polymer translocation and a two-state model for stochastic resonance, we have derived analytical formulas for criteria for emergence of stochastic resonance during polymer translocation. We show that no stochastic resonance is possible if the free energy barrier for polymer translocation is purely entropic in nature. The polymer chain exhibits stochastic resonance only in the presence of an energy threshold in terms of polymer-pore interactions. Once stochastic resonance is feasible, the chain entropy controls the optimal synchronization conditions significantly. [ABSTRACT FROM AUTHOR]

In this paper, we have demonstrated that resonant activation (RA) is possible even in a thermodynamically closed system where the particle experiences a random force and a spatio-temporal frictional coefficient from the thermal bath. For this stochastic process, we have observed a hallmark of RA phenomena in terms of a turnover behavior of the barrier-crossing rate as a function of noise correlation time at a fixed noise variance. Variance can be fixed either by changing temperature or damping strength as a function of noise correlation time. Our another observation is that the barrier crossing rate passes through a maximum with increase in coupling strength of the multiplicative noise. If the damping strength is appreciably large, then the maximum may disappear. Finally, we compare simulation results with the analytical calculation. It shows that there is a good agreement between analytical and numerical results. [ABSTRACT FROM AUTHOR]

In this present research, a superhydrophobic cotton fabric exhibiting a water contact angle of 155.2° has been prepared via dip‐coating technique involving silica nanoparticle deposition followed by silane hydrophobization. Interestingly, the mirror‐like phenomenon was also observed at the interface between was and modified cotton fabric. The surface morphology and microstructure of the modified fabrics were characterized by scanning electron microscope (SEM) and energy dispersive x‐ray spectroscopy (EDX). Fourier transform infrared spectroscopy (FTIR) was performed for functional group detection on a modified cotton surface. For practical applications, the washing durability was characterized by measuring contact angle values before and after washing cycles. Besides this, the durability of the superhydrophobic cotton fabric was measured under different harsh environmental conditions such as highly acidic, neutral, and highly basic environment. After each measurement, water contact angles and sliding angles were measured for dynamic stabilities. Again the modified coated cotton fabric showed strong resistance to the various organic solvents. Along with the above studies, the physical and mechanical durability of the coated fabric was also measured for both industrial and household importance. [ABSTRACT FROM AUTHOR]

A simple pyridine-dicarbohydrazide based colorimetric and fluorometric chemosensor L was designed and synthesized for Al3+ ion sensing in organo aqueous solution. In the presence of Al3+ ions, probe L exhibited visible color changes and fluorescence enhancement (20-fold) due to Al3+ induced chelation-enhanced fluorescence (CHEF) effects. Chemosensor L revealed high selectivity toward Al3+ ions by "turn-on" fluorescence among the other competitive metal ions examined with a detection limit of 0.8 μM. Probe L was found to bind with Al3+ ions in a 1 : 2 (probe : metal) stoichiometric fashion, with an association constant (Ka) of 4.26 × 104 M−2. In addition, DFT and TDDFT calculations were carried out to recognize the binding nature and electronic properties of probe L and its Al-complex. Furthermore, the in situ prepared [L–Al] complex was able to detect HF2− anions via a metal displacement strategy. The bioimaging application of Al3+ and HF2− was implemented in living human liver cancer cells (Hep G2). [ABSTRACT FROM AUTHOR]