Showing papers in "International Journal of Applied Mechanics and Engineering in 2014"
TL;DR: In this article, the authors presented the analysis of the potential of using biomass and coal co-firing in the Polish electro energetic system and showed the benefits resulting from an increase of biomass amount in electricity production in one of the largest Polish power stations.
Abstract: The article presents the analysis of the potential of using biomass and coal co-firing in the Polish electro energetic system and shows the benefits resulting from an increase of biomass amount in electricity production in one of the largest Polish power stations. The paper discusses the most often used technologies for biomass co-firing and the potential of using biomass in electricity production in Poland. It also emphasises the fact that biomass co-firing allows a reduction of greenhouse gases emissions to the atmosphere and helps decrease consumption of energy resources. The article also emphasises the economic meaning of increasing the share of renewable energy resources in energy balance, including biomass, due to costs related to greenhouse gases emissions charges. Finally, conclusions from using biomass and coal cofiring in electricity production are presented.
18 citations
TL;DR: In this article, the authors apply weighting logical functions in the analysis of a degree of importance of construction parameters of a hydraulic valve and show that a shorter stabilisation time has a more important value of the weighting coefficient.
Abstract: Abstract In the optimization process, changes in the construction parameters value influence the behaviour of functions depending on time. Weighting logical coefficients for the stabilisation time are taken into consideration here, i.e., a shorter (better) stabilisation time has a more important (bigger) value of the weighting coefficient. An example of applying weighting logical functions in the analysis of a degree of importance of construction parameters of a hydraulic valve is presented in the paper
15 citations
TL;DR: In this article, a mathematical model is conceived in order to analyse and determine the parameters for driving and control of the operation of the novel walking leg solution, where a 5 link belt mechanism with 2 DOF can be adapted for generating similar Jansen mechanism path curve, where the step height of this path can be increased.
Abstract: Abstract From the analysis of Theo Jansen walking mechanism and of the path curve that it describes the reduced capability for crossing over obstacles of the Jansen leg (1 DOF) is pointed out. By using a 5 link belt mechanism with 2 DOF can be adapted for generating similar Jansen mechanism path curve, where the step height of this path can be increased. For this purpose a mathematical model is conceived in order to analyse and determine the parameters for driving and control of the operation of the novel walking leg solution.
14 citations
TL;DR: In this article, the effects of skew angle, aspect ratio, fiber orientation angle and laminate stacking sequence on the natural frequencies of antisymmetric laminated composite skew plates were also studied.
Abstract: The present paper deals with the experimental and finite element studies carried out on free vibration of isotropic and laminated composite skew plates. The natural frequencies were determined using CQUAD8 finite ele- ment of MSC/NASTRAN and comparison made between the experimental values and the finite element solution. The effects of the skew angle and aspect ratio on the nat- ural frequencies of isotropic skew plates were studied. The effects of skew angle, aspect ratio, fiber orientation angle and laminate stacking sequence (keeping total number of layers in the laminate constant) on the natural frequencies of antisymmetric laminated composite skew plates were also studied. The experimental values of the natural fre- quencies are in good agreement with the finite element solution. The natural frequencies generally increase with an increase in the skew angle for any given value of aspect ratio. List of symbols a Plate length b Plate width t Plate thickness NL Number of layers in the laminate E Modulus of elasticity of the material of isotropic plate E1 Young's modulus of the lamina in the longitudinal direction E2 Young's modulus of the lamina in the transverse direction
13 citations
TL;DR: In this paper, the effects of radiation and convection heat transfer in a radial porous fin are considered and the results suggest that the radiation transfers more heat than a similar model without radiation.
Abstract: Abstract In this study, the effects of radiation and convection heat transfer in a radial porous fin are considered. The geometry considered is that of a rectangular profile fin. The porous fin allows the flow to infiltrate through it and solid-fluid interaction takes place. This study is performed using Darcy’s model to formulate the heat transfer equation. The thermal conductivity is assumed to be a function of temperature. The effects of the natural convection parameter Nc , radiation parameter Nr and thermal conductivity parameter m on the dimensionless temperature distribution and heat transfer rate are discussed. The results suggest that the radiation transfers more heat than a similar model without radiation
13 citations
TL;DR: In this article, the temperature fluctuations in tissues based on Penne's bio-heat transfer equation is investigated by applying the Laplace and Hankel transforms to get the solution in a physical form, a numerical inversion technique has been applied.
Abstract: Abstract In the present study, the temperature fluctuations in tissues based on Penne’s bio-heat transfer equation is investigated by applying the Laplace and Hankel transforms. To get the solution in a physical form, a numerical inversion technique has been applied. The temporal and spatial distribution of temperature is investigated with the effect of relaxation time and is presented graphically.
13 citations
TL;DR: In this article, an unsteady magnetohydrodynamic (MHD) two-layered fluids flow and heat transfer in a horizontal channel between two parallel plates in the presence of an applied magnetic and electric field is investigated, when the whole system is rotated about an axis perpendicular to the flow.
Abstract: Abstract An unsteady magnetohydrodynamic (MHD) two-layered fluids flow and heat transfer in a horizontal channel between two parallel plates in the presence of an applied magnetic and electric field is investigated, when the whole system is rotated about an axis perpendicular to the flow. The flow is driven by a constant uniform pressure gradient in the channel bounded by two parallel insulating plates, when both fluids are considered as electrically conducting, incompressible with variable properties, viz. different viscosities, thermal and electrical conductivities. The transport properties of the two fluids are taken to be constant and the bounding plates are maintained at constant and equal temperatures. The governing partial differential equations are then reduced to the ordinary linear differential equations using two-term series. Closed form solutions for primary and secondary velocity, also temperature distributions are obtained in both the fluid regions of the channel. Profiles of these solutions are plotted to discuss the effects of the flow and heat transfer characteristics, and their dependence on the governing parameters involved, such as the Hartmann number, rotation parameter, ratios of the viscosities, heights, electrical and thermal conductivities
13 citations
TL;DR: This work presents a conceptual solution to support the process of rehabilitation of the knee joint which is necessary after arthroscopic surgery and suggests directions for further research.
Abstract: Abstract Existing commercial solutions of the CPM (Continuous Passive Motion) machines are described in the paper. Based on the analysis of existing solutions we present our conceptual solution to support the process of rehabilitation of the knee joint which is necessary after arthroscopic surgery. For a given novel structure we analyze and present proprietary algorithms and the computer application to simulate the operation of our PCM device. In addition, we suggest directions for further research.
11 citations
9 citations
TL;DR: In this article, the influence of bearing surfaces roughness on the pressure distribution and load-carrying capacity of a thrust bearing is discussed and the equations of motion of an Ellis pseudo-plastic fluid are used to derive the Reynolds equation.
Abstract: In the paper the influence of bearing surfaces roughness on the pressure distribution and load-carrying capacity of a thrust bearing is discussed. The equations of motion of an Ellis pseudo-plastic fluid are used to derive the Reynolds equation. After general considerations on the flow in a bearing clearance and using the Christensen theory of hydrodynamic rough lubrication the modified Reynolds equation is obtained. The analytical solutions of this equation for the cases of a squeeze film bearing and an externally pressurized bearing are presented. As a result one obtains the formulae expressing pressure distribution and load-carrying capacity. A thrust radial bearing is considered as a numerical example.
8 citations
TL;DR: The method of determination of the configuration of mechanisms using contour vector notation and the equations for the analysis of the direct and inverse kinematics task are determined.
Abstract: Abstract The paper presents elements of the topology, geometry and the kinematic analysis of a translational parallel mechanism with three degrees of freedom. In such mechanisms the selection of a proper structure and geometry ensures that the driven link maintains a fixed orientation relative to the base. The method of determination of the configuration of mechanisms using contour vector notation was elaborated in the paper. The equations for the analysis of the direct and inverse kinematics task are determined. An analytical procedure for determining the system’s singular positions is presented and illustrated with examples
TL;DR: In this paper, the effects of the panel angle, skew angle, aspect ratio, and length-to-thickness-ratio on the fundamental natural frequency of vibration of isotropic cylindrical skew panels are studied.
Abstract: This paper presents the finite element studies made on free vibration of isotropic and laminated composite cylindrical skew panels. A finite element analysis is performed using CQUAD4 and CQUAD8 elements of MSC/NASTRAN software. The effects of the panel angle, skew angle, aspect ratio, and length-to-thickness-ratio on fundamental natural frequency of vibration of isotropic cylindrical skew panels are studied.The effects of additional parameters such as fiber orientation angle, numbers of layers (keeping total thickness constant), and laminate stacking sequence on the fundamental frequency of vibration of antisymmetric composite laminates have also been studied. During validation and convergence study, it is found that the CQUAD8 element yields more accurate results than the CQUAD4 element. Hence the CQUAD8 element has been employed for the remaining part of the investigation.The fundamental frequency is found to increasewith the panel angle and skew angle.The variation of the fundamental frequency with the number of layers is not appreciable when the number of layers is greater than about 6. It is also seen that the boundary conditions have significant influence on the fundamental frequency.
TL;DR: Versatile graph based methods have been utilized for kinematical analysis of an automotive gear, which allows the detection of possible mistakes as well as a deeper insight into the designed artifact.
Abstract: In the present paper, kinematical analysis of an automotive gear is described. Versatile graph based methods have been utilized for this purpose. An application of mixed, contour and bond graphs gives the same results. It allows the detection of possible mistakes as well as a deeper insight into the designed artifact. The graphs can also be used for further analyses which will be published in a separate document.
TL;DR: In this paper, the authors presented a theoretical analysis of the system comprising an impeller and a balancing device, and the dynamic analysis took into account linearized hydrodynamic forces and moments generated in the longitudinal clearances of the seals of the impeller.
Abstract: Abstract This paper presents the theoretical study of the system comprising an impeller and a balancing device. It deals with the dynamic analysis of the system, i.e., the axial vibrations of the impeller, and the system stability. The dynamic analysis took into account linearized hydrodynamic forces and moments generated in the longitudinal clearances of the seals of the impeller. The theoretical analysis was supplemented with a numerical example with characteristics determined for a real single-stage centrifugal pump
TL;DR: The purpose of the neuro-fuzzy system is the approximation of the nonlinearity of the robotic manipulator’s dynamic to generate a compensatory control.
Abstract: Abstract In this paper, to solve the problem of control of a robotic manipulator’s movement with holonomical constraints, an intelligent control system was used. This system is understood as a hybrid controller, being a combination of fuzzy logic and an artificial neural network. The purpose of the neuro-fuzzy system is the approximation of the nonlinearity of the robotic manipulator’s dynamic to generate a compensatory control. The control system is designed in such a way as to permit modification of its properties under different operating conditions of the two-link manipulator
TL;DR: Taking into account weighting coefficients in the logical tree minimization reflects a physical model of the object being analysed much better.
Abstract: The method of minimization of complex partial multi-valued logical functions determines the degree of importance of construction and exploitation parameters playing the role of logical decision variables. Logical functions are taken into consideration in the issues of modelling machine sets. In multi-valued logical functions with weighting products, it is possible to use a modified Quine - McCluskey algorithm of multi-valued functions minimization. Taking into account weighting coefficients in the logical tree minimization reflects a physical model of the object being analysed much better.
TL;DR: In this paper, the effect of temperature dependent viscosity on a Soret driven ferrothermohaline convection heated from below and salted from above subjected to a transverse uniform magnetic field in the presence of a porous medium was investigated.
Abstract: Soret driven ferrothermoconvective instability in multi-component fluids has a wide range of applications in heat and mass transfer. This paper deals with the theoretical investigation of the effect of temperature dependent viscosity on a Soret driven ferrothermohaline convection heated from below and salted from above subjected to a transverse uniform magnetic field in the presence of a porous medium. The Brinkman model is used in the study. It is found that the stationary mode of instability is preferred. For a horizontal fluid layer contained between two free boundaries an exact solution is examined using the normal mode technique for a linear stability analysis. The effect of salinity has been included in magnetization and density of the fluid. The critical thermal magnetic Rayleigh number for the onset of instability is obtained numerically for sufficiently large values of the buoyancy magnetization parameter M1 using the method of numerical Galerkin technique. It is found that magnetization and permeability of the porous medium destabilize the system. The effect of temperature dependent viscosity stabilizes the system on the onset of convection.
Abstract: Abstract A technique for path synthesis is employed to design a feeder for carrying products between two points. The feeder is assumed to be a one degree of freedom system of six links connected by means of revolute joints. The mathematical basis of the concept is presented. An exemplary solution is presented and discussed
TL;DR: In this article, the design and static analysis of an impeller for a single-stage pump is presented, where the impeller needs to have a properly designed system of longitudinal and lateral clearances on both sides.
Abstract: Abstract This part of the work presents the design and static analysis of an impeller for a single-stage pump. The impeller is directly connected with a balancing device. The impeller needs to have a properly designed system of longitudinal and lateral clearances on both sides. With the simplifying assumptions concerning the flow and distribution of pressure in the longitudinal and lateral clearances, the static analysis involved deriving relationships between the impeller geometry and the basic performance parameters of the pump. A numerical example was used to show the calculation procedure of static characteristics for the predetermined parameters
TL;DR: Sensitivity analysis and parameter estimation were performed using the evolutionary algorithm method and the method itself can be useful when solving problems concerning the displacement and loads analysis in the knee joint.
Abstract: Abstract Position and displacement analysis of a spherical model of a human knee joint using the vector method was presented. Sensitivity analysis and parameter estimation were performed using the evolutionary algorithm method. Computer simulations for the mechanism with estimated parameters proved the effectiveness of the prepared software. The method itself can be useful when solving problems concerning the displacement and loads analysis in the knee joint
TL;DR: In this paper, an MHD free convection flow of an incompressible non-Newtonian viscoelastic fluid past an infinite vertical plate in the presence of a heat source and Soret effect is analyzed.
Abstract: Abstract The present paper deals with the unsteady motion of an MHD free convection flow of an incompressible non- Newtonian viscoelastic fluid past an infinite vertical plate in the presence of a heat source and Soret effect. A parametric study illustrating the influence of various parameters on the temperature, velocity as well as on the skin-friction and rate of heat transfer is conducted. The results of the effect of the magnetic field, the parameter describing the non-Newtonian behavior, and the velocity of suction and injection on both the velocity and temperature distributions are examined and shown graphically
TL;DR: In this paper, the effect of a magnetic field dependent viscosity on a Soret driven ferro thermohaline convection in a rotating porous medium has been investigated using the linear stability analysis.
Abstract: Abstract The effect of a magnetic field dependent viscosity on a Soret driven ferro thermohaline convection in a rotating porous medium has been investigated using the linear stability analysis. The normal mode technique is applied. A wide range of values of the Soret parameter, magnetization parameter, the magnetic field dependent viscosity, Taylor number and the permeability of porous medium have been considered. A Brinkman model is used. Both stationary and oscillatory instabilities have been obtained. It is found that the system stabilizes only through oscillatory mode of instability. It is found that the magnetization parameter and the permeability of the porous medium destabilize the system and the Soret parameter, the magnetic field dependent viscosity and the Taylor number tend to stabilize the system. The results are presented numerically and graphically
TL;DR: In this paper, a generalized model of strain during metal tube bending was derived based on the postulate concerning a local change of the actual active radius with a bending angle in the bend zone.
Abstract: Abstract According to the postulate concerning a local change of the “actual active radius” with a bending angle in the bend zone, a generalized model of strain during metal tube bending was derived. The tubes should be subjected to bending at tube bending machines by the method of wrapping at the rotating template and with the use of a lubricated steel mandrel. The model is represented by three components of strain in the analytic form, including displacement of the neutral axis. Generalization of the model during bending metal tubes at the tube bending machines as compared with the existing papers (Śloderbach, 1999; Śloderbach and Rechul, 2000) consists in including the neutral axis displacement and possibility of determination of strains at each point along the thickness of the wall of the bent tube in the bending and bend zone. The derived scheme of strain satisfies initial and boundary kinematic conditions of the bending process, conditions of continuity and inseparability of strains. The obtained analytic expressions can be classified as acceptable from the kinematic point of view
TL;DR: In this paper, a numerical study on an unsteady flow past an oscillating semi-infinite vertical plate with variable temperature and uniform mass diffusion under the influence of a first order chemical reaction has been carried out.
Abstract: An numerical study on an unsteady flow past an oscillating semi-infinite vertical plate with variable temperature and uniform mass diffusion under the influence of a first order chemical reaction has been carried out. The dimensionless governing equations are solved by an unconditionally stable and fast converging implicit finite difference scheme. The effects of velocity and temperature for different physical parameters such as the chemical reaction parameter, thermal Grashof number, mass Grashof number and time are analysed. It is observed that due to the presence of first order chemical reaction, the velocity increases during a generative reaction and decreases in a destructive reaction.
TL;DR: In this paper, the dynamics of an orthogonal mechanism in the presence of a shaking table of fixed cargo is studied, where the focus is on the vibrational motion of the mechanism in slow-speed motor rotation.
Abstract: Abstract The dynamics of orthogonal mechanism in the presence of a shaking table of fixed cargo is studied. The focus is on the vibrational motion of the mechanism in slow-speed motor rotation. The analysis of the solutions for motion nonlinear equations showed that the angular velocity of the guiding link oscillates according to the harmonic law about a mean value. The character of changing its amplitude, depending on the weight of the cargo and the length of the guiding link, is determined. Dependence of the mean angular velocity on the motor torque is set.
TL;DR: A new version of the Matlab toolbox for modeling and simulation of any mechanisms consisting of open kinematic chains is presented, which renders it possible to define any manipulator described by Denavit-Hartenberg parameters and then connect the mechanisms created in this way into one complex mechanism.
Abstract: Abstract In the paper, a new version of the Matlab toolbox for modeling and simulation of any mechanisms consisting of open kinematic chains is presented. This tool renders it possible to define any manipulator described by Denavit-Hartenberg parameters and then connect the mechanisms created in this way into one complex mechanism. The package can be used for a realistic visualization of robot motion necessary in research, didactic process or during design of a production cell. Available functions render it possible to show a realistic model of a mechanism based on both default and user defined appearance. The toolbox also provides a set of tools for performing simultaneous simulations of many robots and other objects in their workspace. An example illustrating new features of the toolbox, presenting modeling and motion simulating of human upper limb is also attached.
TL;DR: In this paper, a finite difference solution of an unsteady flow past an oscillating semi-infinite vertical place with variable temperature and uniform mass flux is presented, where the fluid considered here is a gray, absorbing-emitting radiation but a non-scattering medium.
Abstract: Abstract A finite difference solution of an unsteady flow past an oscillating semi-infinite vertical place with variable temperature and uniform mass flux is presented here. The fluid considered here is a gray, absorbing-emitting radiation but a non-scattering medium. The dimensionless governing equations are solved by an efficient, more accurate, and unconditionally stable and fast converging implicit scheme. The steady state velocity, temperature and concentration profiles are shown graphically. The effect of velocity and temperature for different physical parameters such as the thermal radiation, Schmidt number, thermal Grashof number and mass Grashof number is studied. It is observed that the velocity decreases in the presence of thermal radiation. It is also observed that the time taken to reach a steady-state is more in the case of vertical plate than horizontal plate.
TL;DR: In this article, a fluid flow and heat transfer analysis of an electrically conducting non-Newtonian power law fluid flowing over a non-linear stretching surface in the presence of a transverse magnetic field taking into consideration viscous dissipation effects is investigated.
Abstract: Abstract A fluid flow and heat transfer analysis of an electrically conducting non-Newtonian power law fluid flowing over a non-linear stretching surface in the presence of a transverse magnetic field taking into consideration viscous dissipation effects is investigated. The stretching velocity, the temperature and the transverse magnetic field are assumed to vary in a power-law with the distance from the origin. The flow is induced due to an infinite elastic sheet which is stretched in its own plane. The governing equations are reduced to non-linear ordinary differential equations by means of similarity transformations. By using quasi-linearization techniques first linearize the non linear momentum equation is linearized and then the coupled ordinary differential equations are solved numerically by an implicit finite difference scheme. The numerical solution is found to be dependent on several governing parameters, including the magnetic field parameter, power-law index, Eckert number, velocity exponent parameter, temperature exponent parameter, modified Prandtl number and heat source/sink parameter. A systematic study is carried out to illustrate the effects of these parameters on the fluid velocity and the temperature distribution in the boundary layer. The results for the local skin-friction coefficient and the local Nusselt number are tabulated and discussed.
TL;DR: In this article, a great deal of interest has been focused on Adomian's Decomposition Method (ADM) and its applications to a wide class of physical problems containing fractional derivatives (Rida and Sherbiny, 2008; Saha Ray et al., 2008; Datta, 2007; Kaya, 2006; Jiang, 2005; Sutradhar, 2009).
Abstract: Recently, a great deal of interest has been focused on Adomian’s Decomposition Method (ADM) and its applications to a wide class of physical problems containing fractional derivatives (Rida and Sherbiny, 2008; Saha Ray et al., 2008; Datta, 2007; Kaya, 2006; Jiang, 2005; Sutradhar, 2009). The decomposition method employed here is adequately discussed in the published literature (Wazwaz, 2002; Adomian, 1994; Ngarhasta et al. 2002), but it still deserves emphasis to point out the very significant advantages over other methods. The said method can also be an effective procedure for the solution of the time fractional Fokker-Planck equation by suitable choice of drift and fluctuation term. The fractional differential equations have been used to model many physical and engineering processes such as frequency dependent damping behaviour of materials, motion of a large thin plate in a Newtonian fluid, creep and relaxation function for viscoelastic materials, etc. (Suarez and Shokooh, 1997; Glockle and Nonnenmacher, 1991). Moreover, phenomena in electromagnetics, acoustics, viscoplasticity, electrochemistry are also described by differential equations of fractional order (Podlubny, 1999; Shawagfeh, 2002).
TL;DR: In this article, the effects of thermal radiation on a flow past an impulsively started infinite vertical plate in the presence of a magnetic field have been studied and the dimensionless governing equations are solved by an efficient, more accurate, unconditionally stable and fast converging implicit scheme.
Abstract: Abstract The effects of thermal radiation on a flow past an impulsively started infinite vertical plate in the presence of a magnetic field have been studied. The fluid considered is a gray, absorbing-emitting radiation but non-scattering medium. The dimensionless governing equations are solved by an efficient, more accurate, unconditionally stable and fast converging implicit scheme. The effects of velocity and temperature for different parameters such as the thermal radiation, magnetic field, Schmidt number, thermal Grashof number and mass Grashof number are studied. It is observed that the velocity decreases in the presence of thermal radiation or a magnetic field