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The electrical characteristics of the ferroelectric field-effect transistors (FeFETs) are analyzed numerically and presented in this paper. The metal–ferroelectric–insulator–semiconductor field-effect transistor (MFISFET), among the primary structures, is taken into consideration. The nonsaturated hysteresis loop of the ferroelectric material is described by a novel analytical calculation for the relation of polarization against electric field (P–E). The combined impact of the nonuniform concentrations of electric field charge throughout the channel and the nonsaturated polarization of ferroelectric layers are considered to create a more realistic modeling. The proposed research work also provides an in-depth study of the electrical properties of the GAA-based Nanowire FeFET, exploring important variables including transconductance, subthreshold swing, as well as a threshold voltage. The analytical insights derived from the mathematical framework are consistent with the simulated results obtained with the ATLAS 3D simulator.

Phosphorene is a new two-dimensional material that has great potentials in Nano electronic application, so it has attracted more researchers’ attention nowadays. Indeed, phosphorene is an interesting material in gas sensing, due to its high surface-to-volume ratio and its carrier mobility. Many studies have been reported on phosphorene gas sensing, but there is not enough study on analytical modeling of phosphorene gas sensing properties. In this research, by adopting data from experimental NO₂-based gas sensor, an analytical model of the phosphorene gas sensing behavior is presented. Then, the experimental results of NO₂ gas sensing are compared with the proposed model and acceptable agreement is reported. This new model is adapted to predict phosphorene gas sensing performance in higher NO₂ gas concentrations, which demonstrates, linear relation is established in higher concentrations same as lower ppb NO₂ gas concentration. So, we have predicted the result of NO₂ gas sensing for higher concentration based on experimental sensing.

Coupling resonance mechanism of interfacial fatigue stratification of adhesive and/or welding butt joint symmetric and/or antisymmetric structures excited by horizontal shear waves are investigated by forced propagation analytical solutions derived by plane wave perturbation methods, integral transformation methods and global matrix methods. The influence of materials on the coupled resonance frequency is analyzed and discussed by the analytical methods. Coupling resonance of interface shear stress is a structure inherent property. Even a very small excitation amplitude at the coupling resonance frequency can result in interface shear delamination. The coupling resonance frequency decreases with the increase of interlayer thickness or shear wave velocity difference between substrate and interlayer. The results could be applied to layered and/or anti-layered structural design.

In this paper, problem of squeeze film damping in dual axis torsion microactuators is modeled and closed form expressions are provided for damping torques around tilting axes of the actuator. The Reynolds equation which governs the pressure distribution underneath the actuator is linearized. The resulting equation is then solved analytically. The obtained pressure distribution is used to calculate the normalized damping torques around tilting axes of the actuator. Dependence of the damping torques on the design parameters of the dual axis torsion actuator is studied. It is observed that with proper selection of the actuator's aspect ratio, damping torque along one of the tilting directions can be eliminated. It is shown that when the tilting angles of the actuator are small, squeeze film damping would act like a linear viscous damping. The results of this paper can be used for accurate dynamical modeling and control of torsion dual axis microactuators.

Based on the first-order shear deformation shell theory, an analytical approach is developed to predict the thermal buckling response of an all-edge clamped cylindrical panel. The analytical approach adopts a double Fourier solution method suitable for cylindrical panels. The present solutions are compared with the finite element solutions obtained using ANSYS. The effects of various dimensional parameters are included in the study.

Quasi-three-dimensional (3D) stability and free vibration analyses of bi-axially loaded, simply-supported, sandwich piezoelectric plates with an embedded either a functionally graded (FG) carbon nanotube-reinforced composite (CNTRC) core or a multilayered fiber-reinforced composite (FRC) one are presented. Three different distributions of carbon nanotubes (CNTs) through the thickness of the CNTRC core, i.e. uniformly distributed and FG V-, rhombus- and X-type variations, are considered, and the effective material properties of the CNTRC core are estimated using the rule of mixtures. The Pagano method, which is conventionally used for the analysis of multilayered FRC plates, is modified to be feasible for the study of sandwich hybrid CNTRC and piezoelectric ones, in which Reissner mixed variational theorem, the successive approximation and transfer matrix methods, and the transformed real-valued solutions of the system equations are used. The modified Pagano solutions for the stability and free vibration of multilayered hybrid FRC and piezoelectric plates are in excellent agreement with the exact 3D ones available in the literature, and those for sandwich hybrid CNTRC and piezoelectric plates may be used as the benchmark solutions to assess the ones obtained by using various 2D theories and numerical models.

Studying the dynamics of beams subjected to a moving mass is important due to their wide applications, including railways, machining processes, and microelectromechanical systems (MEMS). Various numerical and analytical approaches have been used for modeling such structures. In this analytical study, we have used a combination of the Optimal homotopy analysis method (Optimal HAM) and enriched multiple scales (MS) to analytically study the dynamics of a simply supported Euler–Bernoulli beam traversed by a moving mass and resting on a viscoelastic foundation. The viscoelastic foundation contributes to the modeling by adding a linear and nonlinear term to the formulation. Further, we have considered a fifth-order nonlinear term to account for the bending vibration of the flexible beam. Using the Galerkin method, we have formed the corresponding ordinary differential equation (ODE). Then, we used the enriched MS Optimal HAM to calculate the dynamic response of the beam. After validating our method by comparing our results with the dynamic results of the beam obtained from finite element analysis (FEA), we investigated the effects of the determining parameters on the beam dynamic response. The effects of the foundation nonlinear and linear terms, the moving load weight, and its velocity have been investigated by studying the variation of the normalized beam lateral deflection versus the normalized moving mass instantaneous position in each case. We showed that the difference between linear and nonlinear modeling results is pronounced, and it becomes more pronounced for faster and heavier moving loads.

The aim of this article is to achieve a parametric modeling of kinematics, geometrical and inertial properties of the various joints and links which constitute an anthropomorphic biped. The result is the automatic creation of virtual models of humanoid bipeds while respecting intrinsically the inertial and geometrical distribution of each link, according only to two parameters: the total mass and the total height of the system. Future developments are to use the analytical parameters of masses and inertia in analytical dynamic models in order to control humanoids having different masses and heights.

The novelty of this paper is the use of four variable refined plate theory for nonlinear analysis of plates made of functionally graded materials. The plates are subjected to pressure loading and their geometric nonlinearity is introduced in the strain–displacement equations based on Von–Karman assumptions. Unlike any other theory, the theory presented gives rise to only four governing equations. Number of unknown functions involved is only four, as against five in case of simple shear deformation theories of Mindlin and Reissner (first shear deformation theory). The plate properties are assumed to be varied through the thickness following a simple power law distribution in terms of volume fraction of material constituents. The theory presented is variationally consistent, does not require shear correction factor, and gives rise to transverse shear stress variation such that the transverse shear stresses vary parabolically across the thickness satisfying shear stress free surface conditions. The fundamental equations for functionally graded plates are obtained using the Von–Karman theory for large deflection and the solution is obtained by minimization of the total potential energy. Numerical results for functionally graded plates are given in dimensionless graphical forms; and the effects of material properties on deflections and stresses are determined. The results obtained for plate with various thickness ratios using the theory are not only substantially more accurate than those obtained using the CPT, but are almost comparable to those obtained using higher order theories having more number of unknown functions.

Compaction and the corresponding viscoelastic behaviors of woven fiber reinforcements are essential to determine the mechanical properties of composite components. Current reported works separately studied the viscoelastic behaviors in partial stage of the compaction process. In contrast, here, we propose a uniform viscoelastic model that can describe the viscoelastic responses in all stages. Systematical experiments of carbon and glass woven fiber reinforcements demonstrate the effectiveness of this viscoelastic model. Moreover, the significances of the model parameters and their underlying relations are clearly revealed. The time constants are not equal in different stages due to different roles of fiber friction played. The relationship among time constants in different stages is found and is experimentally demonstrated. Stress constants strongly depend on the initial stress and types of fiber reinforcements. The relationships between stress constants in all stages are also obtained. The proposed theoretical model here provides a potential and promising approach to understand the viscoelastic responses of woven fiber reinforcements in compaction process.

Congestion control is among primary topics in computer network in which random early detection (RED) method is one of its common techniques. Nevertheless, RED suffers from drawbacks in particular when its "average queue length" is set below the buffer's "minimum threshold" position which makes the router buffer quickly overflow. To deal with this issue, this paper proposes two discrete-time queue analytical models that aim to utilize an instant queue length parameter as a congestion measure. This assigns mean queue length (mql) and average queueing delay smaller values than those for RED and eventually reduces buffers overflow. A comparison between RED and the proposed analytical models was conducted to identify the model that offers better performance. The proposed models outperform the classic RED in regards to mql and average queueing delay measures when congestion exists. This work also compares one of the proposed models (RED-Linear) with another analytical model named threshold-based linear reduction of arrival rate (TLRAR). The results of the mql, average queueing delay and the probability of packet loss for TLRAR are deteriorated when heavy congestion occurs, whereas, the results of our RED-Linear were not impacted and this shows superiority of our model.

Step discontinuities, which are formed in pipeline repair and maintenance, will introduce additional wave scattering in the pipeline diagnosing work. Therefore, an analytical model is established in this paper to investigate the longitudinal wave scattering from a step discontinuity and the influence of discontinuity material on the scattering characteristics in water pipelines. In the model, axial wavenumber, displacement and stress profiles of the unblemished pipeline and discontinuity sections are calculated by a multi-layered cylindrical waveguide model. To concatenate these sections and predict the overall influences of the discontinuity, the mode matching method is applied by enforcing the flexible axial boundary conditions with an extended bi-orthogonality relation. Based on the established model, numerical calculations are carried out to investigate the reflection/transmission characteristics when discontinuity material and attenuation are considered. Both finite element method (FEM) software and laboratory experiments are also conducted for modeling verification: the maximum root mean square errors of the predicted reflection and transmission coefficients are 0.01 and 0.1 compared with FEM and experiment results, respectively. It indicates the proposed model is accurate in predicting the wave scattering from a step discontinuity in a water pipeline with the influence of discontinuity material accounted for. In addition, this pure analytical model introduces advantages in computational cost when modeling long pipelines compared with existing FEM packages.