transverse vibrations of the elastically connected rectangular double membrane compound system abstract the free and forced vibrations of a system of two rectangular membranes attached together by a winkler elastic layer are studied analytically the motion of the system is described by two non homogeneous partial differential equations the solutions of the free vibrations are obtained by the bernoulli fourier method solving the boundary value problem the natural frequencies and the mode shape functions are found the initial value problem is also solved the free vibrations of the double membrane system are realised by synchronous and asynchronous deflections the forced vibrations of membranes subjected to arbitrarily distributed continuous loads are determined by using the classical method of the expansion in a series of the normal modes of vibrations discussing the vibrations caused by the harmonic exciting forces it is shown that the dynamic absorption phenomenon appears therefore the double membrane system can be used as a dynamic vibration absorber as a numerical example the vibrations of the system consisting of two identical membranes subjected to harmonic uniform distributed load are treated in detail

dynamic response of a double euler bernoulli beam due to a moving constant load in this paper the dynamic response of a double beam system traversed by a constant moving load is studied the system consists of two elastic homogeneous isotropic euler bernoulli beams the two simply supported prismatic beams are identical parallel one upon the other and connected continuously by a viscoelastic layer the dynamic deflections of both beams are given in analytical closed forms the effects of the moving speed of the load and the damping and the elasticity of the viscoelastic layer on the dynamic responses of the beams are investigated in detail also several plots of the deflections of the beams are given and discussed for different values of speed parameter damping ratio and stiffness parameter furthermore the force transmitted between the beams is determined and the effects of the system parameters on this force are studied plots of the maximum responses of the beams are presented

the effects of measurement error and vowel selection on the locus equation measure of coarticulationa effects on the slope of introducing error in the f2 hz values in locus equations les and of using fewer than ten vowels were investigated for each of the initial consonants b d g 2000 simulated sets were generated using monte carlo techniques the sets were altered with 50 100 or 200 hz error being randomly applied to each f2 value within a set selected vowels were then removed from the sets and the effects on the slopes were measured results suggest that the le slopes are generally resistant to error and reduced number of vowels effects of adding 50 hz of random error to the f2 values in sets using eight or ten vowels were minimal yielding a mean absolute change in slope less than 0 07

transverse vibrations of elastically connected double string complex system part i free vibrations this paper analyzes the forced transverse vibrations of an elastically connected double string complex continuous system the general solutions of forced vibrations of strings subjected to arbitrarily distributed continuous loads are found by using the method of expansion in a series of the mode shape functions different cases of exciting loadings are analyzed the action of stationary harmonic loads and moving concentrated forces is considered vibrations caused by the harmonic exciting forces are discussed and conditions of resonance and dynamic vibration absorption are formulated thus the string type dynamic absorber can be used to suppress the excessive vibrations of corresponding string systems the dynamic string type damper is a new concept of a continuous dynamic vibration absorber cdva it is shown that a corresponding two degree of freedom discrete system is an analogue of an elastically connected double string complex system theoretical analysis is illustrated by a numerical example

forced transverse vibrations of an elastically connected complex rectangular simply supported double plate system abstract the paper deals with forced transverse vibrations of an elastically connected rectangular double plate system this complex continuous system can represent a certain simplified model of a three layered structure consisting of two parallel thin plates separated by an elastic massless layer of a winkler type undamped motion of the system excited by arbitrarily distributed continuous loadings subjected transversely to both plates are governed by a linear set of two coupled non homogeneous partial differential equations based on the kirchhoff love plate theory the forced vibration problem is solved generally by the application of the modal expansion method in the case of simply supported boundary conditions for plates on the basis of general solutions obtained three particular cases of the action of exciting stationary harmonic loads are considered an analysis of harmonic responses of the system makes it possible to determine conditions of resonance and dynamic vibration absorption a numerical example is given to illustrate the theory presented

an asymptotic solution of the governing equation for the natural frequencies of a cantilevered coupled beam model abstract an asymptotic solution is presented for the natural frequencies mode shapes of a cantilevered coupled beam model a three term expansion is obtained for the frequency which shows good agreement with exact values over a wide range of the stiffness parameter the first three mode shapes are also presented for large and show good agreement for the first and second modes agreement for the third mode improves as gets larger the modeled structure behaves essentially as a shear beam except in the immediate neighborhood of the ends

free transverse vibrations of elastically connected simply supported double beam complex system abstract in this paper the free vibration analysis of two parallel simply supported beams continuously joined by a winkler elastic layer is presented the motion of the system is described by a homogeneous set of two partial differential equations which is solved by using the classical bernoulli fourier method the natural frequencies of the system are determined the initial value problem is considered to find the final form of the free vibrations the free vibrations of an elastically connected double beam complex system are realized by synchronous and asynchronous deflections the presented theoretical analysis is illustrated by a numerical example in which the effect of physical parameters characterizing the vibrating system on the natural frequencies is investigated

vibration of a double beam system abstract an exact method is presented for solving the vibration of a double beam system subject to harmonic excitation the system consists of a main beam with an applied force and an auxiliary beam with a distributed spring k and dashpot c in parallel between the two beams the viscous damping and the applied forcing function can be completely arbitrary the damping is assumed to be neither small nor proportional and the forcing function can be either concentrated at any point or distributed the euler bernoulli model is used for the transverse vibrations of beams and the spring dashpot represents a simplified model of viscoelastic material the method involves a simple change of variables and modal analysis to decouple and to solve the governing differential equations respectively a case study is solved in detail to demonstrate the methodology and the frequency responses are shown in dimensionless parameters for low and high values of stiffness k k0 and damping c c0 the plots show that each natural mode consists of two submodes 1 the in phase submode whose natural frequencies and resonant peaks are independent of stiffness and damping and 2 the out of phase submode whose natural frequencies are increased with increasing stiffness and resonant peaks are decreased with increasing damping the closed form solution and the plots especially the three dimensional ones not only illustrate the principles of the vibration problem but also shed light on practical applications

free transverse vibrations of an elastically connected rectangular simply supported double plate complex system abstract in this paper the free transverse vibrations of a system of two rectangular simply supported thin plates connected by a homogeneous winkler elastic layer are investigated analytically the small vibrations of the system are described by a set of two partial differential equations based on the kirchhoff love plate theory next the homogeneous equations of motion are solved by using the classical navier method the natural frequencies of the system in the form of two infinite sequences are determined and the corresponding mode shapes of vibration are shown as a consequence an elastically connected double plate complex system executes two kinds of the free vibrations synchronous and asynchronous the initial value problem is then considered to find the final form of the free vibrations the theoretical analysis presented is illustrated by a numerical example in which the free vibrations of a system of two identical plates are discussed in detail

on connected sums and legendrian knots abstract we study the behavior of legendrian and transverse knots under the operation of connected sums as a consequence we show that there exist legendrian knots that are not distinguished by any known invariant moreover we classify legendrian knots in some non legendrian simple knot types

free transverse vibrations of an elastically connected complex beam string system abstract the present work is devoted to theoretical vibration analysis of a complex mixed continuous system undamped free transverse vibrations of an elastically connected beam string system are considered solutions of the problem are formulated by using the modal expansion method two infinite sequences of the natural frequencies corresponding to two possible kinds of vibration motions synchronous and asynchronous are determined in a numerical example illustrating the theory presented the effect of string tension force on the natural frequencies of the system is investigated in detail

free vibrations of elastically connected stretched beams abstract a general theory for the determination of natural frequencies and mode shapes for a set of elastically connected axially loaded euler bernoulli beams is developed a normal mode solution is applied to a set of non dimensional coupled partial differential equations the natural frequencies are the eigenvalues of a matrix of differential operators the matrix operator is shown to be self adjoint leading to an orthogonality condition for the mode shapes in the special case of identical beams it is shown that the natural frequencies are organized into sets of intramodal frequencies in which each mode shape is a product of a spatial mode and a discrete mode an exact solution is available for the general case however the natural frequencies and mode shapes are then determined using a complicated numerical method a rayleigh ritz method using mode shapes of the corresponding unstretched beams is developed as an alternative

differential algebra of legendrian links let the space r q p u be equipped with the standard contact form du pdq a link l r3 is called legendrian if the restriction of to l vanishes two legendrian links are said to be legendrian isotopic if they can be connected by a path in the space of legendrian embeddings consider the map r3 r2 q p u q p since the kernel of d is everywhere transverse to the kernel of the projection l of a legendrian link l is an immersed curve we say that a link l r3 is generic with respect to or generic if all self intersections of l are transverse double points given a generic legendrian link l its diagram is the curve l r2 at every crossing of which the overpassing branch the one with the larger value of u is marked it is well known that every smooth link type can be realized by a legendrian link it is shown in sect 11 that such a realization can be chosen to have a diagram with relatively few crossings the so called classical invariants of an oriented legendrian link l are defined as follows first of them is just the smooth isotopy type of l let l1 lk be the components of l the maslov number m li of li is twice the rotation number of li the thurston bennequin number li of li is the linking number between li and s li where s is a small shift along the u direction the orientation on r3 involved in the definition of the linking number is given by the form d dq dp du in terms of the diagram li is the number of double points of li counted with signs shown in fig 1 the thurston bennequin number does not depend on the orientation of li while the maslov number changes its sign when the orientation changes

new modified multi level residue harmonic balance method for solving nonlinearly vibrating double beam problem abstract in this study a new modified multi level residue harmonic balance method is presented and adopted to investigate the forced nonlinear vibrations of axially loaded double beams although numerous nonlinear beam or linear double beam problems have been tackled and solved there have been few studies of this nonlinear double beam problem the geometric nonlinear formulations for a double beam model are developed the main advantage of the proposed method is that a set of decoupled nonlinear algebraic equations is generated at each solution level this heavily reduces the computational effort compared with solving the coupled nonlinear algebraic equations generated in the classical harmonic balance method the proposed method can generate the higher level nonlinear solutions that are neglected by the previous modified harmonic balance method the results from the proposed method agree reasonably well with those from the classical harmonic balance method the effects of damping axial force and excitation magnitude on the nonlinear vibrational behaviour are examined

computational vibration and buckling analysis of microtubule bundles based on nonlocal strain gradient theory abstract a nonlocal strain gradient model is proposed to study buckling and vibrational responses of microtubules in axons with attention to different size effect parameters based on finite element method supporting effects of surrounding cytoplasm and map tau proteins are considered microtubules are modeled as elastically connected improved timoshenko nano beams resting on a two parameter pasternak foundation differential equations are discretized using galerkin method finally two eigenvalue problems are solved to achieve critical buckling loads and frequencies of single and doubled microtubule systems the nonlocal strain gradient model is employed in order to show both hardening and softening effects of structural stiffness based on relative magnitudes of nanoscale parameters influence of size effects including nonlocal nanoscale parameter gradient coefficient and surface effects are examined for various boundary conditions and some benchmark results are reported it is observed that these effects are more prominent at higher modes based on presented numerical results map tau proteins strengthen doubled microtubule systems to bear 11 7 more buckling load than a single microtubule furthermore vibration frequencies of microtubules depend on their physical surrounding condition in cell such as cell matrix and membrane and since microtubules could be employed as biosensors this property may be used in order to detect malignant tumors based on vibrational damping

an ozsvath szabo floer homology invariant of knots in a contact manifold abstract using the knot floer homology filtration we define invariants associated to a knot in a three manifold possessing non vanishing floer co homology classes in the case of the ozsvath szabo contact invariant we obtain an invariant of knots in a contact three manifold this invariant provides an upper bound for the thurston bennequin plus rotation number of any legendrian realization of the knot we use it to demonstrate the first systematic construction of prime knots in contact manifolds other than s 3 with negative maximal thurston bennequin invariant perhaps more interesting our invariant provides a criterion for an open book to induce a tight contact structure a corollary is that if a manifold possesses contact structures with distinct non vanishing ozsvath szabo invariants then any fibered knot can realize the classical eliashberg bennequin bound in at most one of these contact structures

damping of beam vibrations by means of a thin constrained viscoelastic layer evaluation of a new theory abstract in this paper a new one dimensional theory of beams damped by means of a thin viscoelastic film is presented based upon a prescribed piecewise linear longitudinal displacement field and a shear stress field satisfying continuity conditions at the interfaces the beam formulation of the proposed theory is derived in order to demonstrate the accuracy of this beam model numerical tests were carried out by using the finite element method the present results are compared with well known analytical finite element with the msc nastran computer program and experimental solutions under various material temperature and boundary conditions it is found that the proposed theory is very simple and efficient in predicting the dynamic response of beams that are damped by means of a thin viscoelastic film

evaluation of a strategy for automatic formant tracking variations on an automatic formant tracking strategy developed at alberta will be compared to manual formant measurements from two databases of vowels spoken by men women and children in texas or michigan correct vowel formant candidates for f1 f2 and f3 may be found roughly 85 90 percent of the time for adult male speakers using autocorrelation lpc with the following settings f3 maximum at 3000 hz lpc order of 14 sampling rate of 10 khz j markel and a gray linear prediction of speech springer new york 1975 experience shows good results are also often found with females and children s speech provided the sampling rate and f3 maximum are scaled appropriately for each speaker our new basic strategy involves analyzing each utterance at several distinct sampling rates and coordinated f3 cutoff frequencies with a fixed lpc order each scaling choice provides an independent set of candidates that is post processed by a simple tracking algorithm a correlation measure between a spectrogram of the original signal and one resynthesized from each estimated track set is defined this measure is combined with other heuristic figures of merit based on e g continuity formant ranges and bandwidths to choose the best analysis

likelihood ratio forensic voice comparison using parametric representations of the formant trajectories of diphthongs non contemporaneous speech samples from 27 male speakers of australian english were compared in a forensic likelihood ratio framework parametric curves polynomials and discrete cosine transforms were fitted to the formant trajectories of the diphthongs a e o a and the estimated coefficient values from the parametric curves were used as input to a generative multivariate kernel density formula for calculating likelihood ratios expressing the probability of obtaining the observed difference between two speech samples under the hypothesis that the samples were produced by the same speaker versus under the hypothesis that they were produced by different speakers cross validated likelihood ratio results from systems based on different parametric curves were calibrated and evaluated using the log likelihood ratio cost function cllr the cross validated likelihood ratios from the best performing system for each vowel phoneme were fused using logistic regression the resulting fused system had a very low error rate thus meeting one of the requirements for admissibility in court

on transversally simple knots this paper studies knots that are transversal to the standard contact structure in ir 3 bringing techniques from topological knot theory to bear on their transversal classification we say that a transversal knot type t k is transversally simple if it is determined by its topological knot type k and its bennequin number the main theorem asserts that any t k whose associated k satisfies a condition that we call exchange reducibility is transversally simple as applications we give a new proof of a theorem of eliashberg el91 which asserts that the unknot is transversally simple and with the help of a new theorem of menasco me99 extend a result of etnyre et99 to prove that all iterated torus knots are transversally simple we show that the concept of exchange reducibility is the simplest of the constraints that one can place on k in order to prove that any associated t k is transversally simple we also give examples of pairs of transversal knots that we conjecture are not transversally simple

free vibration analysis of elastically connected multiple beams by using the adomian modified decomposition method abstract the adomian modified decomposition method amdm is employed in this paper to investigate the free vibrations of n elastically connected parallel euler bernoulli beams which are continuously joined by a winkler type elastic layer the proposed amdm method can be used to analyze the vibration of beam system consisting of an arbitrary number of beams by using boundary conditions the natural frequencies and corresponding mode shapes can be easily obtained simultaneously the numerical results for different boundary conditions beam numbers and the stiffness of the winkler type elastic layer are presented it is shown that the amdm offers an accurate and effective method of free vibration analysis of multiple connected beams with arbitrary boundary conditions

synthesis fidelity and time varying spectral change in vowels recent studies have shown that synthesized versions of american english vowels are less accurately identified when the natural time varying spectral changes are eliminated by holding the formant frequencies constant over the duration of the vowel a limitation of these experiments has been that vowels produced by formant synthesis are generally less accurately identified than the natural vowels after which they are modeled to overcome this limitation a high quality speech analysis synthesis system straight was used to synthesize versions of 12 american english vowels spoken by adults and children vowels synthesized with straight were identified as accurately as the natural versions in contrast with previous results from our laboratory showing identification rates 9 12 lower for the same vowels synthesized using the cascade formant model consistent with earlier studies identification accuracy was not reduced when the fundamental frequency was held constant across the vowel however elimination o

vibrations of double string complex system under moving forces closed solutions in this paper the dynamic response of a double string system traversed by a constant or a harmonically oscillating moving force is considered the force is moving with a constant velocity on the top string the strings are identical parallel one upon the other and continuously coupled by a linear winkler elastic element the classical solution of the response of a double string system subjected to a force moving with a constant velocity has a form of an infinite series the main goal of this paper is to show that in the considered case a part of the solution can be presented in a closed analytical form instead of an infinite series the presented method of finding the solution in a closed analytical form is based on the observation that the solution of the system of partial differential equations in the form of an infinite series is also a solution of an appropriate system of ordinary differential equations

cabling and transverse simplicity we study legendrian knots in a cabled knot type specifically given a topological knot type c we analyze the legendrian knots in knot types ob tained from k by cabling in terms of legendrian knots in the knot type k as a corollary of this analysis we show that the 2 3 cable of the 2 3 torus knot is not transversely simple and moreover classify the transverse knots in this knot type this is the first classification of transverse knots in a non transversely simple knot type we also classify legendrian knots in this knot type and exhibit the first example of a legendrian knot that does not destabi lize yet its thurston bennequin invariant is not maximal among legendrian representatives in its knot type in this paper we continue the investigation of legendrian knots in tight contact 3 manifolds using 3 dimensional contact topological methods in eh1 the authors introduced a general framework for analyzing legendrian knots in tight contact 3 manifolds there we streamlined the proof of the classification of legendrian unknots originally proved by eliashberg eraser in ef and gave a complete classification of legendrian torus knots and figure eight knots in eh2 we gave the first structure theorem for legendrian knots namely the reduction of the analysis of connected sums of legendrian knots to that of the prime summands this yielded a plethora of non legendrian simple knot types a topological knot type is legendrian simple if legendrian knots in this knot type are determined by their thurston bennequin invariant and rotation number moreover we exhibited pairs of legendrian knots in the same topological knot type with the same thurston bennequin and rotation numbers which required arbitrarily many stabilizations before they became legendrian isotopic see eh2