The study has considered the connection between the satellite and the earth as one of the underlying and complicated issues in the field of aerospace. Because of the complexity of the issue and necessity of precision and speed in designing equipment and observation, many scholars work in this field. The first step in the field of making telecommunication connection between the earth station and satellite is modeling location of earth station and modeling movement of the satellite in its circuit. The issue of movement of telecommunication equipment in the defined route is very important. In this study, after direct kinematic modeling of the mechanism of a signal on antenna and modeling earth's rotation and satellite period in the relevant circuit, a controller was finally needed to control status of satellite and direction of signal mechanism on antenna towards earth station. Therefore, with designing a suitable controller such as LQR controller and taking simulations, preservation of signal on antenna towards earth station was shown. The results obtained from applying this controller on the presented models show the favorable performance of the controller.
In this paper, we characterize translation surfaces such as translation surfaces of type-I and type-II in pseudo-Galilean 3-space G(3)(1). Then we study some classification of translation surfaces of type-I in pseudo-Galilean 3-space G(3)(1) under the condition Delta r=Ar, where A is an element of R-3x3 the set of 3 x 3 real matrices. Also we give a theorem to classify translation surfaces of type-I in pseudo-Galilean 3-space G(3)(1) under the condition Delta G = AG, where G is the Gauss map, and A = (a(ij)), i, j =1, 2, 3.
In this paper, we introduce a new efficient numerical approach for solving of mixed 2D nonlinear Volterra-Fredholm integral equations. The fundamental structure of this method is based on the using of 2D Haar wavelets. Next, a detailed error analysis for the method is presented by applying the Banach fixed point theorem. This theorem guarantees that under certain assumptions, the analyzed equations would have a unique fixed point. Finally, some numerical examples are given to show the accuracy of the method, and results are compared with other numerical methods.
In this paper we introduce an approach to increase density of field-effect transistors and diodes in a high-voltage current driver. By using the approach we consider manufacturing the driver in heterostructure with specific configuration. Several required areas of the heterostructure should be doped by diffusion or ion implantation. After that dopant and radiation defects should by annealed by using optimized scheme. We also consider an approach to decrease value of mismatch-induced stress in the considered heterostructure. We introduce an analytical approach to analyze mass and heat transport in heterostructures during manufacturing of integrated circuits with account of mismatch-induced stress.
There are many micro-organisms, including sperm, that move in confined geometries. With sperm as a motivating example, we investigate emergent trajectories and beat forms of an actuated filament as it approaches a stationary and planar wall in three dimensions. There is a multiscale coupling of the surrounding fluid flow and the elastic filament, represented as a Kirchhoff rod, exerting both forces and torques on the fluid. The actuation of the filament is determined by the spatiotemporal preferred curvature and twist, which corresponds to either a planar (sinusoidal), quasi-planar, or helical wave. A regularized image system is used to solve for the Stokes flow in the half-space above the wall, accounting for the no-slip boundary condition at the wall. In the presence of a wall, the swimming speed and angle of the swimmer near the wall varies based on the preferred flagellar bending as well as the plane that the swimmer is initialized in relative to the wall. We observe that swimming perpendicular to the wall at a distance of approximately 0.3 microns from the wall is a stable swimming pattern for all three actuations when the filament's centerline is initialized perpendicular (or perpendicular with a rotation less than or equal to +/-pi/3) to the wall.
The derailment model of a 51-DOF railway vehicle including coupling effects of the longitudinal and lateral modes was theoretically built by investigating the geometrical and dynamical effects of the lateral acceleration, gyro factors and mechanical factors such as flange angle, friction coefficient, effective radius of the wheel and track gauge. The lateral dynamic of the railway vehicle comprising lateral, vertical displacement and roll, yaw, pitch angular displacements of each six wheelset, three bogie frames, and vehicle body was modeled in detail. Depending on this model, the initiation of different kind of derailments such as wheel lifting, wheel climbing, roll-over and their synthesis can be predicted. In addition, the effects of vehicle speed on derailment quotient (DQ)'s were investigated under various suspension parameters and curved track radius. Main objective of the development of such a numerical model is to analyze various dynamical and geometrical influences on the wheelset, which is not considered in conventional derailments models such as those based on Nadal and Weinstock criteria.
This paper includes new bounds concepting the vanishing generalized weighted Morrey space. In this sense, it is outlined improved bounds about the a class of fractional type rough higher order commutators on vanishing generalized weighted Morrey spaces.
In this paper, we investigate the bisector surfaces generated by spatial curves via split quaternions in E-1(3). We consider the bisector surfaces between two split quaternionic curves in Minkowski 3-space. This case is shown to yield rational bisector surfaces. Moreover, we give degenerate cases of these curves. Then, we provide some examples of rational bisector surfaces of two spatial quaternionic curves.
Aero elastic flutter as a means of harvesting energy from ambient fluid flow is a topic of active research. (1-3) Such a design is even more crucial for micro scale devices such as MEMS, where due to scaling effects, friction becomes prohibitively high to use successful macro scale designs involving sliding such as a rotary fan. MEMS sensors require miniscule energy and powering those using batteries, whose life is a function of their size, is counterproductive to their usage as tiny sensing units. Hence the energy harvested in the manner described above can be used to power continuously operating remote MEMS sensors with application in structural health monitoring, smart dust, body prosthetics etc. One of the measures taken for increasing the efficiency of this system is to increase the vorticity of the flow before it hits the vibrating elements. This is achieved by placing a bluff body in front of the flow to generate vortex trail (G. W. Taylor, et al., IEEE Journal of Oceanic Engineering 26, 539 (2001)). Properly designed device, e.g.: one with resonant frequency equal to vortex shedding frequency would flutter in this flow with high amplitude. With a piezoelectric strip attached to this fluttering device, the vibrational energy can be converted to electrical and can either be directly used or stored in tiny rechargeable batteries. We present a systematic design of this system, with a cantilever shaped vibrating element. Using CFD based numerical analysis we determine the best design for the bluff body in providing the most turbulent flow. Using the POD modes generated for the flow field, we also determine the best location for the placement of this device. The designs are validated using coupled Fluid structure based simulations performed in Abaqus.
This paper obtains the soliton solutions of a system of coupled nonlinear Schrodinger type equations (CNLSE). Two analytical approaches, namely; the sine-Gordon expansion method (SGEM) and the generalized tanh (GTH) method are used to extract the kink-type, bell-shaped, kink-bell shaped, singular and combined solitons.
In this study, the modified Kudryashov and Riccati-Bernoulli (sub-ODE) methods are applied to construct some analytical solutions of the nonlinear Foam-drainage equation which plays an important part in the formation and evolution of liquid foams. Kink type, singular and logarithmic function solutions are obtained. Then, the residual power series method (RPSM) is used to analyze the numerical behavior of the equation by considering all the exact solutions. We observed that the modified Kudryashov and Riccati Bernoulli sub-ODE methods are powerful techniques for finding the exact solutions to various nonlinear models. Also, the RPSM is efficient for examining numerical behavior of nonlinear models. Some interesting figures are shown to show the reliability of the methods.
In this article, numerical solutions of the fractional Biswas-Milovic equation with m = 4, which defines the long-space optical communications, are obtained by using the residual power series method (RPSM). The RPSM also helps to obtain Maclaurin expansion of the solution. Solutions of this equation are computed via convergent series and its representations are given by using the Mathematica software package. Explanations and consequences of the method are presented by graphical models. It is finally shown that this technique is an efficient method for the solution of the fractional Biswas-Milovic equation.
In this paper, we present new soliton solutions for the time fractional nonlinear Pochhammer-Chree equation (NPCE) with conformable derivative. The generalized tanh function (GTF) method is employed to extract such solutions for the underlying equation. Physical features of some of the obtained soliton solutions are illustrated through 3 and 2 dimensional plots. The GTF method is very efficient in establishing solitons for fractional differential equations.
We establish the existence and shape of periodic solutions of the singular differential delay equation epsilon(X)over dot(t)+x(t) = f(x(t - 1)), epsilon > 0 under the assumptions that the continuous nonlinearity f(x) satisfies the negative feedback condition, x . f(x) < 0, Co) x not equal 0, has sufficiently large derivative at zero vertical bar f'(0)vertical bar, and possesses an invariant interval 1(sic) 0 , f(1) subset of 1, as the one-dimensional map. As epsilon -> 0(+) we show the convergence of the periodic solutions to a discontinuous square Ca wave function generated by the globally attracting 2-cycle of the map f. Differential delay equations of this type find numerous applications in various fields of science and engineering such as physics and laser optics, mathematical biology, physiology, and economics, nonlinear boundary value problems for hyperbolic partial differential equations, others.
In this paper, new dark and singular solutions are constructed for the generalized nonlinear Schrodinger equation with higher order dispersion and cubic-quintic nonlinear terms using a relatively new technique, namely the generalized exponential rational function method (GERFM). Moreover, the modulation instability analysis (MIA) of the underlying equation is studied by using linear-stability analysis and the gain spectrum in the modulation instability is computed. Numerical simulations are made to shed light on characteristics of the obtained solutions.
In this study, electrical responses of conductive granular mixtures over a wide frequency range were investigated by focusing on the universal power-law scaling. The studied granular packings with various proportion of conductive grains were considered as resistor-capacitor networks based on contact fabrics and interfacial properties. With prescribed contact networks constructed from the discrete element method, we employed both percolation theories and circuit simulation to compute electrical responses, both of which well predict the span of power-law regimes obtained in experimental observations. This study reveals the role of percolation in controlling electrical responses of conductive granular materials and provide insight into testing techniques for granular energy materials and systems.
In this paper, first we analyze the geometry of a moving particle in a 3-dimensional ordinary space in terms of parallel adapted frame elements. Then, we compute energy on each parallel vector fields in the space. We also obtain a necessary condition of having a critical point for the energy functional of unit parallel vector fields by only using the geometric description of the curvature of the worldline belonging to the particle. Finally, we give the condition of the minimizing energy for frictional, gravitational, and normal force vector fields by considering the critical curve among the class of all curves in space.
In the present paper, general coupled system of nonlinear time-space fractional Schrodinger equations is considered in multi-dimensional case. Finite difference method is used to construct the difference schemes for one and multidimensional problems for general coupled system of nonlinear time-space fractional Schrodinger equations. A reformulation of Grunwald-Letnikov difference derivative is used to construct the difference schemes. Convergence and stability results are presented. Numerical experiments are carried out on problems with one and two dimensional space variables.
In this article, we propose new method to find a nondominated solution of a specific type of nonlinear fuzzy optimization problems, where all coefficients of the objective function and the constraints are triangular fuzzy numbers. For this purpose we use alpha-cuts of the triangulare fuzzy numbers to convert the main problem to an interval nonlinear programming problem. The nondominated solution of the original problem by solving the interval programming problem is obtained. To illustrate the efficiency of the method, some examples have been solved.
Due to high impact toughness of leather, it is assumed that reinforcement of polyurethane foams (PU) with micro-particles of leather will impart good energy absorbing capabilities. Hence, the present work focuses on use of buffing dust (BD) obtained from processing of leather in tannery as reinforcement filler in PU foam. PU foams are modified with BD in range of 1-3 wt% and are compared with neat PU foam. Also, an effort has been made to understand effect of mould end conditions on the variation it brings to properties. To this end, two different types of molds are used; one of cylindrical shape with free top end (free foaming) and constrained top end (constrained foaming). It is found that BD addition leads to noticeable change in density, microstructure and mechanical properties under compression. The results show that compared to the neat foam of density 0.042 g/cc, composition modified with BD provides density in range of 0.044-0.047 g/cc. All types of PU foams are subjected to compression test at strain rate of 0.002 s(-1), 0.02 s(-1) and 0.2 s(-1) to 80% compression. The most promising of all samples is 1 wt% BD PU foam which showed a rise in specific elastic modulus and specific plateau stress compared to neat PU foam sample. The energy absorption capacity of 1 wt% sample depicted by efficiency curve shows a rise in peak efficiency parameter by 39, 22 and 12% at strain rates of 0.002 s(-1), 0.02 s(-1) and 0.2 s(-1) respectively in contrast to neat PU foam sample. The elastic recovery measured after compression test is also improved for 1 wt% BD PU for given value of strain rate. In multiple cyclic compression tests, the energy dissipated for each cycle is higher for 1 wt% sample possibly due to formation of stiffer cell walls which resists more against cell collapse by buckling, yielding or crushing.
