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The current research article explores the bio-convection magnetized Carreau-nanofluid flow utilizing activation energy and magnetic dipole. Magnetic nanomaterials have significant effect on the magnetized behavior of ferrofluids which leads to robust the changes in fluid viscosity and thermophysical characteristics. Darcy-Forchheimer flow model is also present. Thermal conductivity of nanofluid is dependent on the temperature. Brownian motion and thermophoresis aspects are also accounted. The PDEs are reduced to set of ODEs via appropriate functions. Numerical solutions are achieved with the help of the famous bvp4c solver a built-in function in MATLAB. Numerous flow parameters are graphically and numerically presented with physical significance. The proposed findings could be useful for applications of extrusion systems, organic compounds, improved energy generation and improved manufacturing techniques.

In this study, we investigate a new fourth-order integrable nonlinear equation. Firstly, by means of the efficient Hirota bilinear approach, we establish novel types of solutions which include breather, rogue, and three-wave solutions. Secondly, with the aid of Lie symmetry method, we report the invariance properties of the studied equation such as the group of transformations, commutator and adjoint representation tables. A differential substitution is found by nonlinear self-adjointness (NSA) and thereafter the associated conservation laws are established. We show some dynamical characteristics of the obtained solutions through via the 3-dimensional and contour graphs.

Cost-effective synthesis, portability, quick response and fascinating features of semiconducting metal oxide sensors have drawn much accredited to be utilized in wide variety of potential sensing applications. Herein, flexible acetone sensor was fabricated through spray coating method using different conductive inks of carbon nanotubes (CNTs), zinc oxide (ZnO) and silver (Ag) nanoparticles solutions on cellulose paper. Morphological analysis revealed the fiber like morphology of cellulose over which CNTs, ZnO and Ag nanoparticles are uniformly distributed. The energy dispersive X-ray spectroscopic analysis was performed to observe the elemental composition in the as-prepared samples. The recovery time toward acetone was greater for CNTs/Ag acetone sensor at 95% as compared to CNTs/ZnO/Ag sensor. Additionally, sensing time of the samples towards acetone was measured and the observed response time was greater for CNTs/ZnO/Ag (0.52 s) acetone sensor as compared to CNTs/Ag sensor (0.41 s). Hence, CNTs/ZnO/Ag can be easily employed for sensing applications due to quick response.

This research aims to discuss and control the chaotic behaviour of an autonomous fractional biological oscillator. Indeed, the concept of fractional calculus is used to include memory in the modelling formulation. In addition, we take into account a new auxiliary parameter in order to keep away from dimensional mismatching. Further, we explore the chaotic attractors of the considered model through its corresponding phase-portraits. Additionally, the stability and equilibrium point of the system are studied and investigated. Next, we design a feedback control scheme for the purpose of chaos control and stabilization. Afterwards, we introduce an efficient active control method to achieve synchronization between two chaotic fractional biological oscillators. The efficiency of the proposed stabilizing and synchronizing controllers is verified via theoretical analysis as well as simulations and numerical experiments.

The aim of this research is to propose a new fractional Euler-Lagrange equation for a harmonic oscillator. The theoretical analysis is given in order to derive the equation of motion in a fractional framework. The new equation has a complicated structure involving the left and right fractional derivatives of Caputo-Fabrizio type, so a new numerical method is developed in order to solve the above-mentioned equation effectively. As a result, we can see different asymptotic behaviors according to the flexibility provided by the use of the fractional calculus approach, a fact which may be invisible when we use the classical Lagrangian technique. This capability helps us to better understand the complex dynamics associated with natural phenomena.

The exceptional high surface area and wide band gap ranges of semiconductor metal oxide nanostructures owe unique chemical, optical and physical properties that have grabbed their utilization for humidity sensing applications. In this framework, cost-effective sensors have been fabricated using a simple spray coating technique. Initially, the sonication was carried out for all the conductive inks such as carbon nanotubes (CNTs), zinc oxide (ZnO) and silver (Ag) nanoparticles (NPs) for 15 min in each case and then sprayed over conducting cellulose polymer substrate. Surface study demonstrated conducting networks of CNTs and cellulose polymer, and layers of ZnO and Ag NPs, as well. The analysis of elemental composition confirmed the required stoichiometric contents. Sensing measurement of CNTs/ZnO/Ag sample showed smaller resistance and enhanced current as compared to CNTs/ZnO sample. Hence, the device showed an efficient activity to sense humidity.

In this new study, we investigate the motion of a forced mass-spring-damper in a vertical position. First, the classical Lagrangian as well as the classical Euler–Lagrange equation of motion are constructed. Then the fractional Euler–Lagrange equation is derived by extending the classical Lagrangian in the fractional sense. In this extension, a new form of the fractional derivative is employed including a general function as its kernel. The derived fractional Euler–Lagrange equation is then converted into a system of linear algebraic equation by designing an efficient matrix approximation approach. The numerical findings are reported verifying the theoretical investigations. According to the results, some remarkable thinks are achieved; indeed, the numerical simulations show that different aspects of the system under study can be explored with regard to the flexibility found in selecting the kernel contrary to the traditional fractional models.

This article addresses the numerical approximation of third-grade nanoliquid flow over a stretchable rotating disk in the existence of nano-sized particles and gyrotactic motile microorganisms. The behavior of bioconvection is contemplated. The comportment of mixed convection, activation energy and Joule heating effects are also considered. Further the nano-characteristics for Brownian dispersion of fluid particles and thermophoresis aspect are also taken into account. Utilizing appropriate scaling group of transformation variables, the partial differential equations are converted into governing ordinary differential system. Then coupled ordinary differential equations are tackled numerically by using shooting technique via built-in function bvp4c solver with the help of computational software MATLAB. Graphical impact of miscellaneous arising sundry parameters on distribution, volumetric concentration of nano-particles, velocity field and rescaled density of motile micro-organisms are scrutinized and deliberated. The present model plays a crucial role in sectors of industry and engineering. This model is suitable for heating and cooling including engine cooling, microelectronics, biotechnology, bio-microsystems, cancer therapy, fertilizers and biofuel etc. Furthermore, the temperature distribution is enhanced for larger values of thermal radiation parameter.

Highly sensitive and extremely stretchable piezoresistive strain sensors have shown intense applications in wearable electronics. In this context, a comparative study of stretchable strain sensors based on hybrid layers of silver nanoparticles and carbon nanotubes spray coated on stretchable textile is presented in this manuscript. For this persistence, three stretchable and highly flexible electrodes are fabricated: first devoid of pre-strain, second with 25 × 25% multiaxial pre-strain, and third with 50 × 50% multiaxial pre-strain. Pre-strain technique was employed to improve the stretchability and resistance stability of the electrodes. Surface morphology and elemental composition of the as-prepared electrodes were analyzed via scanning electron microscope associated with energy-dispersive detector. The fabricated electrodes were used for the assembly of strain sensors. The sensing measurements revealed high sensitivity, significant stretchability, and fast response of the fabricated strain sensors. Cost-effective and extremely facile fabrication strategy as well as direct fabrication on textile substrates can be significant advancements in fabrication of strain sensors for practical applications in human motion detection and wearable electronics.

Winter dormancy of temperate zone perennial plant species is commonly released by chilling temperature. If the duration of the cold weather is not adequate, plant growth becomes disorganized leading to reduced growth, spread out flowering and fruit maturation and often reduced yield. In mild-winter regions, growers commonly resort to spraying their trees with chemicals such as hydrogen cyanamide to compensate for the lack of chilling to ensure good growth and yield. Although effective, most of these chemicals are highly toxic; unfortunately, there is no effective and environmentally friendly alternative which can be used to release dormancy. In this work, we present a cold plasma treatment-based method which can effectively release the dormancy of grape buds. We have found that exposing grape buds to plasma provides improvement of several growth parameters including higher, faster and more synchronous budbreak and more vigorous vegetative growth, comparatively similar to or better than natural chilling. Biochemical analyses of bud tissue suggest that the plasma treatment triggered a marked transient oxidative stress as indicated by the increase in the concentrations of free proline, malondialdehyde (MDA) and hydrogen peroxide (H2O2). Proline appears to have played a key role; as a compatible osmolyte, it may have protected cellular structures against free radicals and as a signaling molecule, it may have induced the events leading to dormancy release. We anticipate that our work will provide a starting point for the development of novel plasma-based tools and methods to treat dormant plants. The plasma treatment method may allow higher agricultural production in several regions of the world at risk of becoming marginal for the cultivation of certain crops due to global warming.

The present study aims to investigate a new fractional model describing the dynamical behaviour of the tuberculosis infection. In this new formulation, we use a recently introduced fractional operator with Mittag–Leffler nonsingular kernel. To solve and simulate the proposed model, a new and efficient numerical method is developed based on the product-integration rule. Simulation results are provided and some discussions are given to verify the theoretical analysis. The results indicate that employing the nonsingular operator can extract the hidden aspects of the model under consideration while these features are invisible when we use the ordinary time-derivatives. Therefore, the non-integer calculus supplies more flexible models describing the asymptotic behaviours of the real-world phenomena and helps us to better understand their complex dynamics.

Internet-of-Things (IoT) is no longer just a buzzword. “Things” that are immensely connecting to the Internet, are now creating “Smart” systems. However, heterogeneous devices and the dominance of propriety protocols are still the major challenges for practical application of such systems. This research work presents a practical application of a real-time microwave sensing system for the evaluation of tissues moisture. The work addresses two major challenges; first, the use of a highly sensitive microwave sensor to determine tissue moisture; second, to share the measurement with the remote users through an IoT-based system over the Bluetooth low-energy radio using open standards and protocols. The prototype shows significant changes in its resonance frequency, return loss and bandwidth (5.5%–26%) for the measured moisture content, which is also validated. This implementation demonstrates the feasibility of real-time monitoring of food quality. It also enables data-analytics that may help the industries to improve product quality, supply-chain and predicts demand in a more effective manner.

In this work buried channel devices were successfully integrated in HKMG. Analog, noise and reliability performance have been reported and compared to a surface device. The devices were processed to have the same V Tsat for the nominal geometry of a corresponding surface device. Advantages and drawbacks of the two integrations are discussed and explained with the support of calibrated TCAD simulations.

Everyone is talking about coronavirus from the last couple of months due to its exponential spread throughout the globe. Lives have become paralyzed, and as many as 180 countries have been so far affected with 928,287 (14 September 2020) deaths within a couple of months. Ironically, 29,185,779 are still active cases. Having seen such a drastic situation, a relatively simple epidemiological SIR model with Caputo derivative is suggested unlike more sophisticated models being proposed nowadays in the current literature. The major aim of the present research study is to look for possibilities and extents to which the SIR model fits the real data for the cases chosen from 1 April to 15 March 2020, Pakistan. To further analyze qualitative behavior of the Caputo SIR model, uniqueness conditions under the Banach contraction principle are discussed and stability analysis with basic reproduction number is investigated using Ulam–Hyers and its generalized version. The best parameters have been obtained via the nonlinear least-squares curve fitting technique. The infectious compartment of the Caputo SIR model fits the real data better than the classical version of the SIR model (Brauer et al. in Mathematical Models in Epidemiology 2019). Average absolute relative error under the Caputo operator is about 48% smaller than the one obtained in the classical case ($\nu =1$ ν = 1 ). Time series and 3D contour plots offer social distancing to be the most effective measure to control the epidemic.

This article examines magnetohydrodynamic three-dimensional (3D) squeezed flow by a rotating permeable channel subject to Dufour and Soret impacts. Impact of viscous dissipation is also considered. An applied magnetic field is considered subject to electrically conducting viscous fluid. The change from the non-linear partial differential framework to the non-linear ordinary differential framework is assumed into position by utilizing appropriate variables. Governing differential frameworks are computed numerically by shooting method. Numerical results have been achieved by considering numerous values of emerging flow parameters. Contributions of influential parameters on physical quantities are studied thoroughly. Surface drag coefficients and mass and heat transport rates are also processed and examined. Furthermore, the concentration and temperature distributions are reduced for larger values of Soret number. The prime interest of presented study is to model and examine the Dufour and Soret aspects in concentration and energy expressions. To our knowledge, no such analysis has been addressed in the literature yet.

This paper presents the characterization and reliability results achieved on 1.8 V 4 Mb flash array built around 3rd generation Embedded SuperFlash® (ESF3) memory cell featuring high-k metal gate (HKMG) select transistor and embedded into Low-Power 28 nm CMOS HKMG technology with gate-first architecture. Endurance shows better performance in terms of erase degradation as compared to prior technology nodes with poly-SiON select transistor. This improvement is attributed to HKMG-related process integration scheme allowing to reduce the effect of the CMOS baseline on tunnel oxide quality. Excellent program-erase performance, program disturb windows and data retention capability are observed.

We study the influence of higher-order effects such as third order dispersion (TOD), fourth order dispersion (FOD), quintic nonlinearity (QN), self steepening (SS) and second order nonlinear dispersion (SOND) on the dynamics of dissipative soliton (DS) in metamaterials. Considering each higher-order effect as a perturbation to the system and following Lagrangian variational method, we demonstrate stable dynamics of DS as a result of the interplay between different higher-order effects. We also perform numerical analysis to confirm the analytical results., Comment: Accepted for publication in Physics Letters A

This study examines Darcy-Forchheimer 3D nanoliquid flow caused by a rotating disk with heat generation/absorption. The impacts of Brownian motion and thermophoretic are considered. Velocity, concentration, and thermal slips at the surface of the rotating disk are considered. The change from the non-linear partial differential framework to the non-linear ordinary differential framework is accomplished by utilizing appropriate variables. A shooting technique is utilized to develop a numerical solution of the resulting framework. Graphs have been sketched to examine how the concentration and temperature fields are affected by several pertinent flow parameters. Skin friction and local Sherwood and Nusselt numbers are additionally plotted and analyzed. Furthermore, the concentration and temperature fields are enhanced for larger values of the thermophoresis parameter.

Graphene devices have been widely explored for photonic applications, as they serve as promising candidates for controlling light interactions resulting in extreme confinement and tunability of graphene plasmons. The ubiquitous presence of surface crumples in graphene, very less is known on how the crumples in graphene can affect surface plasmon resonance and its absorption properties. In this article, a novel approach based on the crumpled graphene is investigated to realize broadband tunability of plasmonic resonance through the mechanical reconfiguration of crumpled graphene resonators. The mechanical reconfiguration of graphene crumples combined with dual electrostatic gating (i.e. raising the Fermi level from 0.2–0.4 eV) of graphene serves as a tuning knob enabling broad spectral tunability of plasmonic resonance in the wavelength range of 14–24 µm. The crumpled region in the resonators exhibits an effective trapping potential where it extremely confines the surface plasmonic field on the surfaces of crumples providing localized surface plasmon resonance at the apices of these crumples. Finally, to achieve near-unity absorption >99% at the resonance wavelengths (17 µm and 22 µm) crumpled graphene resonators are loaded with four ring shaped metamaterials which result in the enhanced near-field intensity of ≈1.4×106. This study delivers insight into the tunability of crumpled graphene and their coupling mechanism by providing a new platform for the flexible and gate tunable graphene sensors at the infrared region.

The aim of this study is to assess the effect of argon gas (0–30%) addition in pure nitrogen and nitrogen‑hydrogen admixture on the surface properties of plain carbon steel by cathodic cage plasma nitriding. The surface hardness is obtained using hardness tester, phase composition is evaluated by X-ray diffraction, surface features are observed using scanning electron microscope (SEM) along with energy-dispersive X-ray spectroscopy (EDS) and wear rate is assessed using the ball-on-disc tester. Insignificant change in hardness is found in nitrogen plasma (with or without argon admixing), whereas it is expressively improved in nitrogen-hydrogen mixture plasma. The samples treated in nitrogen atmosphere mainly contains oxides, whereas iron nitrides in the nitrogen-hydrogen atmosphere, both with and without argon. The thickness of the modified layer is drastically changed with gasses composition, and the thick layer is achieved in nitrogen‑hydrogen admixture. The wear rate is also significantly improved while using nitrogen‑hydrogen mixture, and best results are achieved by using 20% argon in this mixture. This study reveals that although argon addition can enhance the reactive species production, however the presence of hydrogen is compulsory to improve the surface properties.

As magnetic cooling refrigerant, Ni–Mn–Sn Heusler alloys have gained significant potentials for a wide range of practical applications as compared with other expensive Ga-doped Ni–Mn based Heusler alloys, toxic As and P doped Mn-based alloys and rare-earth elements like Gd-based alloys. Consequently, an inclusive investigation on magnetostructural transition and magnetocaloric features of Ni43Mn47−xMoxSn10 alloys is carried out. The alloys are assembled through arc-melting technique and their X-ray diffraction analysis confirms their B2-type crystal structure at room temperature. As the Mo contents are increased, the magnetostructural transition temperature increases for a temperature range between Curie temperature of austenite and martensite phases. Obvious metamagnetic behavior and magnetic hysteresis are observed in isothermal magnetization curves, suggesting that the temperature and magnetic field can be used as robust tools for tuning the structural transformation in Heusler alloys. The noticeable magnetocaloric effect suggests that the prepared alloys can be an attractive choice for magnetic refrigeration applications.

The cathodic cage plasma nitriding (CCPN) is an innovative surface engineering method, which overcomes the shortcomings associated with conventional plasma nitriding (CPN). In current study, optical emission spectroscopy (OES) and optical actinometry are used to diagnose the electron, vibrational and rotational temperature, relative active species density (N, N2+) and nitrogen dissociation fraction in hydrogen admixed nitrogen plasma (with 4% argon as actinometer) in CCPN reactor. The electron temperature is estimated using modified Boltzmann plot method, vibrational temperature using N2(C, v′) state distribution, while rotational temperature is estimated using Boltzmann plot method. To estimate the nitrogen dissociation fraction, actinometery as well as intensity ratio method is employed. The electron and vibrational temperature depicts an increasing trend, while rotational temperature decreases with hydrogen admixture. The relative density of [N] is found to be increasing up to 40% hydrogen admixture, however, relative density of [N2+] is decreasing. This study presents clear picture of hydrogen admixing on the surface characteristics: it depicts that with hydrogen admixture, in addition to oxide layer removal and increased ionization, the generation of active species is also influenced. It suggests that with regard to both N and N2+ density, 40% hydrogen is beneficial.

This paper studies optical soliton perturbation with spatio-temporal dispersion by trial equation method. There are five types of nonlinear fibers studied in this paper. They are quadratic-cubic law, anti-cubic law, cubic-quintic-septic law, triple-power law and log-law. Bright, dark and singular soliton solutions are recovered. In addition, singular periodic solutions naturally emerge as a byproduct of this integration mechanism.

The modified simple equation scheme is employed to secure dark and singular optical soliton solution to the perturbed Gerdjikov-Ivanov equation that models pulse dynamics in optical fibers and PCF. The solvability conditions for this algorithm is also presented. National Science Foundation for Young Scientists of Wuhan Donghu University (2017dhzk001) Department of Mathematics and Statistics at Tshwane University of Technology South African National Foundation (92052 IRF1202210126) National Research Foundation of Korea Qatar National Research Fund (QNRF) (NPRP 8-028-1-001)

This paper obtains dark and singular resonant optical soliton solutions with anti-cubic noinlinearity. Riccati-Bernoulli sub-ODE method is the integration algorithm adopted in this paper. There are constraint conditions that are also listed and these guarantee the existence of such solitons.

This paper obtains optical soliton solution to perturbed Gerdjikov-Ivanov equation by trial equation approach. Bright, dark and singular soliton solutions are derived. Additional solutions such as singular periodic solutions also emerge of this integration scheme. National Science Foundation for Young Scientists of Wuhan Donghu University (2017dhzk001) Department of Mathematics and Statistics at Tshwane University of Technology South African National Foundation (92052 IRF1202210126) National Research Foundation of Korea Qatar National Research Fund (QNRF) (NPRP 8-028-1-001)

This paper secures dark and singular optical soliton solution to the perturbed Kundu–Eckhaus equation where the perturbation terms appear with full nonlinearity. The integration algorithm adopted in this paper is the modified simple equation approach. The solitons appear with certain parameter restrictions that are listed as constraints.

This paper studies the resonant optical solitons that comes with anti-cubic nonlinearity in presence of Hamiltonian perturbation terms. The extended trial function method is employed to retrieve cnoidal waves, bright and singular soliton solutions as well as periodic singular solutions to the model.

We present an extensive study of the magnetic properties of a novel La0.5Ba0.5MnO3 perovskite material prepared by the hydrothermal method. The explored sample was structurally studied by the x-ray diffraction (XRD) method which confirms the formation of a pure cubic phase of a perovskite structure with Pm3m space group. The magnetic properties were probed by employing temperature M (T) and external magnetic field M (μoH) dependence of magnetization measurements. A magnetic phase transition from ferromagnetic to paramagnetic phase occurs at 339 K in this sample. The maximum magnetic entropy change ( $\left | {{\Delta } S}_{M}^{\max } \right |$ ) took a value of 1.4 J kg− 1 K− 1 at the applied magnetic field of 4.0 T for the explored sample and has also been found to occur at Curie temperature (TC). This large entropy change might be instigated from the abrupt reduction of magnetization at TC. The magnetocaloric effect (MCE) is maximum at TC as represented by M (μoH) isotherms. The relative cooling power (RCP) is 243.2 J kg− 1 at μoH = 4.0 T. Moreover, the critical properties near TC have been probed from magnetic data. The critical exponents δ, β, and γ with values 3.82, 0.42, and 1.2 are close to the values predicted by the 3D Ising model. Additionally, the authenticity of the critical exponents has been confirmed by the scaling equation of state and all data fall on two separate branches, one for T TC, signifying that the critical exponents obtained in this work are accurate.

A higher-order nonlinear Schrodinger equation with the third-order dispersion, the cubic–quintic nonlinearities, derivative non-Kerr nonlinear terms, Kerr dispersion, and stimulated inelastic scattering is considered. The model can be used to describe the subpicosecond or femtosecond optical pulse propagation in highly nonlinear optical fibers. We find the exact gray solitary wave solution (i.e., a dark localized structure with nonzero minimum in intensity) on a continuous-wave background for the equation by adopting an appropriate ansatz solution. The propagation characteristics of such solitary pulses are determined in the presence of all higher-order effects. We also find black solitary wave solutions for the higher-order evolution equation under specific conditions for its coefficients. The parametric conditions on fiber parameters for the existence of both types are given.

This paper obtains optical soliton solutions to the Kundu Eckhaus equation with general coefficients. The Riccati Bernoulli's sub-ODE method as well as Kudryashov's scheme are employed to obtain soliton solutions to the model. This generalized earlier reported result of the model with specific coefficients. Subsequently, the multiplier approach was utilized to secure a conserved quantity with the bright soliton solution that was reported earlier. Young Foundation of Wuhan Donghu University (2017DHKZ001) Department of Mathematics and Statistics at Tshwane University of Technology South African National Foundation (92052 IRF1202210126) Qatar National Research Fund (QNRF) (NPRP 8-028-1-001)

This paper employs the extended trial equations algorithm to extract soliton and other forms of waves in quadratic-cubic nonlinear medium. These waves stem from the continuous spectrum. The solutions appear with their corresponding constraints, also known as the existence criteria for the waves.

We consider the evolution of ultrashort pulses in metamaterials wherein the pulse propagation is governed by the generalized nonlinear Schrodinger equation with higher-order effects such as pseudo-quintic nonlinearity and self-steepening effect. We present three new types of exact singular soliton-like solutions for the model in the presence of the self-steepening term, whose phase chirping varies as a function of the pulse intensity. The obtained results indicate that the parameters of solutions are directly related the self-steepening parameter. Parametric conditions on physical parameters for the existence of the novel structures are also presented. Particular cases are discussed.

Propagating chirped soliton solutions for the Chen–Lee–Liu equation also called the derivative nonlinear Schrodinger II equation are investigated by application of the ansatz method. The model incorporating self-steepening term has many applications in nonlinear optical fibers and plasma physics. A nonlinear differential equation describing the evolution of the wave amplitude in the nonlinear media is derived by means of the coupled amplitude-phase formulation. Special exact chirped soliton solution that takes the shape of “W” is determined for the first time in presence of all physical effects. It is shown that the nonlinear chirp associated with this type of solitons is crucially dependent on the wave intensity and related to self-steepening and group velocity dispersion parameters. Parametric conditions on system parameters for the existence of the chirped soliton structure are also presented. This soliton solution exists due to a balance among group velocity dispersion and self-steepening effect solely.

An optical graphene-metal hybrid antenna geometry, permitting the efficient tuning of plasmon resonance with unity absorption is reported. The total optical absorption and optical field enhancement are accomplished by designing a graphene-metal antenna. The antenna is comprised of gold hexagon radiator with bilayer graphene on the top, functioning as a double plasmonic resonant structure. The tunability of absorption and optical field enhancement is realized by electrical gating. The strong coupling takes place between the gold plasmons and graphene plasmons, resulting in the strong enhancement of optical fields. The proposed design is modeled in CST Microwave Studio and is simulated through FDTD solver. Moreover, the dynamic tuning of the resonance frequency and optical absorption is achieved by increasing the chemical potential of graphene layers through gate voltage. The tuning range of the designed antenna is optimized in a bandwidth starting from 30 THz to 34 THz. Although at 33 THz the antenna meets matching conditions by having high input impedance, low admittance, and almost unity absorption. The functioning bandwidth of the antenna is preferable for plasmonic applications i.e. infrared sensing and imaging, where high absorption and enhanced field characteristics are required.

This paper obtains bright optical soliton solutions from resonant nonlinear Schrodinger’s equation by the aid of semi-inverse variational principle. The two forms of nonlinear media studied are par...

In this work, a duplex cathodic cage plasma nitriding (CCPN) process is performed using aluminum (pre and post treatment) and stainless steel cathodic cages. The duplex treated samples are also compared with the single treatments. The nitrided samples are analyzed with Vickers micro-hardness tester, X-ray diffraction and scanning electron microscope along with energy dispersive spectroscopy. It is found that the duplex post-aluminum CC process attains a surface hardness of ∼1124 HV; far higher than the other treated samples and previously reported in the literature. The crystal structure of post-aluminum nitrided samples shows the dominant aluminum nitride phase. The compatibility of the reported process with the existing industrial systems makes it promising for large-scale industrial uses.

Aluminum and its alloys are widely employed in aerospace and automobile industries. However, they exhibit poor surface properties, which considerably reduce their applicability. The titanium nitride (TiN) coatings deposited by physical vapor deposition (PVD) are extensively used on aluminum due to their excellent surface features. Unfortunately, TiN coatings contain pores, voids, and pinholes; as well as they get oxidized during machining, which significantly reduces their surface hardness. In this work, we have investigated a hybrid coating combining TiN (deposited by PVD) with cathodic cage plasma nitriding (CCPN), in alternating sequence, to improve the surface properties of aluminum. The results show that post-CCPN treatment of TiN coating attains higher surface hardness, better wear resistance and excellent film quality due to combined diffusion of iron, nitrogen, and substrate aluminum in TiN. Also, the problem of pores has been eliminated. The results are contradictory to the conventional routine in duplex coatings, where pre-plasma nitriding is typically used.

We investigate the extended nonlinear Schrodinger equation with higher-order odd and even terms. The model includes additional higher-order dispersion and nonlinear terms that are most important for applications in fiber optics, in the case of the Heisenberg spin chain, and for ocean waves. Special exact solutions in the form of a dipole soliton is obtained, by adopting a complex amplitude ansatz composed of the product of bright and dark solitary waves. The conditions on the system parameters for the existence of this localized structure are also reported. The derived solution characteristically exists due to a balance among physical effects of different nature. Numerical results and discussions are also presented.

This paper obtains conservation laws for the cubic–quartic nonlinear Schrodinger's equation that is proposed to be an alternative model for soliton propagation, when the group velocity dispersion is negligibly small. Two laws of nonlinearity are considered, namely Kerr law and power law. The multiplier method obtains the conserved densities for the model, with these two laws.

In this paper, we present the exact bright and singular optical solitons of the nonlinear Schrodinger equation with third and fourth order dispersion terms. The method of undetermined coefficients is applied to obtain the reported solutions. The cases of Kerr law and power law nonlinearity are taken into account. We also find the conditions concerning the optical material parameters for the existence of these soliton structures. The results are useful in describing the propagation of optical solitons in highly dispersive media with Kerr and power law nonlinearity.

This paper applied extended trial equation algorithm to obtain dispersive optical solitons in DWDM system that is governed by the Schrodinger–Hirota equation with Kerr law nonlinearity. Bright and singular soliton solutions are reported.

This paper obtains optical soliton solutions to the Lakshmanan–Porsezian–Daniel model. The method of undetermined coefficients is applied to extract these solutions. Bright, dark and singular soliton solutions are obtained and the constraint conditions for the existence of these solitons are presented.

This paper obtains resonant soliton solutions to the nonlinear Schrodinger's equation that is studied in quadratic-cubic nonlinear media. The semi-inverse variational principle is applied to retrieve the soliton solution. The soliton parameters appear with restrictions that are also presented.

This paper obtains bright and singular optical soliton solutions in nonlinear negative-index materials that appears with quadratic-cubic nonlinearity. The applied integration algorithm is the extended trial equation. Additional waves such as plane waves, periodic singular waves also emerge as a byproduct of this scheme.

The perturbed nonlinear Schrodinger's equation with anti-cubic nonlinearity is studied with the aid of semi-inverse variational principle. The perturbation terms that are included are inter-modal dispersion, third and fourth order dispersion, nonlinear dispersion and self-steepening term, the last two of which appear with full nonlinearity.

We investigate the dynamics of ultrashort pulses in nano optical fibers that is governed by improved nonlinear Schrodinger equation with dual-power law nonlinearity with Hamiltonian perturbation terms. A set of entirely new soliton solutions with nonlinear chirp is derived for the first time. The chirped solutions comprise of bright, dark and singular solitons, illustrating the potentially rich set of localized structures with nontrivial phase for the improved model. It was shown that the nonlinear chirp associated with each of these optical solitons is dependent on the pulse intensity. The restrictions on physical parameters for the existence of chirped soliton pulses are also listed.

Soliton perturbation theory is applied to obtain the adiabatic variation of its parameters and slow change in velocity. The dynamical system leads to a stable fixed point to which the soliton amplitude and frequency gets locked into for a stable propagation down the fibers with anti-cubic nonlinearity.