Theory Of Lord Research Articles

Singing Formula of Kelong Jaga (Kajang Oral Tradition)

This study focuses on the formula of Kelong Jaga. This study used a descriptive qualitative method in which data were the lyrics of Kelong Jaga then analyzed based on theory of Lord (1981). The result shows that singers of Kelong Jaga use ready common repeated pattern from tradition but in some certain part they usually have to improvise the lyric. The way of learning of Kelong Jaga starts from listening the performance in every opportunity, then practicing in leisure time, and finally trying to get the opportunity to perform in front of the real audience. The formula is distinguished in some parts, namely line analysis, parallel sense, and filler occurred in the Kelong Jaga. It is involved by some ideas that generally mean having good attitude to others, as a guest and as a host. It is involved some ideas namely, 1) Respecting ada’; 2) Party or feast; 3) Telling story about a single girl; 4) Unity and kinship; 5) Giving the best service to the guest; 6) Acting the best attitude to the host; and 7) Keeping earth or environment. It is suggested to youth to learn and perpetuate kelong jaga as oral tradition in Kajang community, thus extinction threat could be avoided.
 Keywords: Singing formula, Kelong Jaga, oral tradition, Kajang community.

Related dynamic axisymmetric thermoelectroelasticity problem for a long hollow piezoceramic cylinder

Introduction. The article studies the problem of investigation of coupled nonstationary thermoelectroelastic fields in piezoceramic structures. The main approaches related to the construction of a general solution to the initial non-selfadjoint equations describing the process under consideration are briefly outlined. The work aims at constructing a new closed solution to the axisymmetric thermoelectroelasticity problem for a long piezoceramic cylinder.Materials and Methods. A long hollow cylinder whose electrodated surfaces were connected to a measuring device with large input resistance was considered. On the cylindrical surfaces of the plate, a time-varying temperature was given. The hyperbolic theory of Lord–Shulman thermo-electro-elasticity was used. The closed solution is constructed using a generalized method of finite integral transformations.Results. The developed calculation algorithm makes it possible to determine the stress–strain state of the cylinder, its temperature, and electric fields. In addition, it becomes possible to investigate the coupling of fields in a piezoceramic cylinder, as well as to analyze the effect of relaxation of the heat flow on the fields under consideration.Discussion and Conclusion. The use of assumptions about the equality of the components of the temperature stress tensor and the absence of temperature effect on the electric field allowed us to formulate a self-adjoint initial system of equations and construct a closed solution.

Generalized thermoelasticity of a piezoelectric layer

In the present research, the response of a one-dimensional piezoelectric layer is investigated using the generalized thermoelasticity theory of Lord and Shulman. The layer is subjected to thermal shock on one surface. Three coupled equations, namely, motion equation, energy equation and Maxwell equation in terms of displacement, temperature, and electric potential are established. Using the proper transformation, the mentioned equations are given in a dimensionless form. These equations are discretized by means of the generalized differential quadrature method and traced in time by means of the Newmark time marching scheme. Numerical examples are provided to show the propagation and reflection of thermal, mechanical and electrical waves in a layer. It is shown that under the Lord and Shulman theory, temperature propagates with a finite speed, similar to mechanical displacement wave. However, the electric displacement and potential propagate with infinite speed.

Effect of the rotation of generalized thermoelastic layer subjected to harmonic heat: state-space approach

The theory of generalized thermoelasticity, based on the theory of Lord–Shulman (L-S) with one relaxation time, is used to solve boundary value problems of a one-dimensional layer of semi-infinite elastic medium. We considered the medium is rotating, and one of its boundaries subjected to harmonic heat and traction free, and the other boundary connected to the rigid foundation and has zero heat flux. The governing partial differential equations are solved in the Laplace transform domain by using the state-space approach of the modern control theory. The inverse Laplace transforms are obtained numerically. The temperature, the displacement, and the stress distributions are represented graphically with some comparisons to stand on the effect of the rotation of the medium and the harmonic heat on all the studied functions.

Effect of the thermal relaxation and magnetic field on generalized micropolar thermoelasticity

The model of generalized micropolar magneto-thermoelasticity for a thermally and perfectly conducting half-space is studied. The initial magnetic field is parallel to the boundary of the half-space. The formulation is applied to the generalized thermo-elasticity theories of Lord and Shulman, Green and Lindsay, as well as to the coupled dynamic theory. The normal mode analysis is used to obtain expressions for the temperature increment, the displacement, and the stress components of the model at the interface. By using potential functions, the governing equations are reduced to two fourth-order differential equations. By numerical calculation, the variation of the considered variables is given and illustrated graphically for a magnesium crystal micropolar elastic material. Comparisons are performed with the results predicted by the three theories in the presence of a magnetic field.

Modification of Shock Resistance for Cutting Tools Using Functionally Graded Concept in Multilayer Coating

In this study, thermal analysis and optimization of the material composition in functionally graded (FG) cutting tools were carried out to achieve the minimum thermal stress. Since cutting tool particularly rotating ones in milling process are exposed to thermal shock during machining, a complicated analysis is required to analyze the thermal shock response. Therefore, a generalized coupled thermoelasticity theory of Lord–Shulman based on second sound effect is adopted. Lord–Shulman theory, as a generalized coupled thermoelasticity, is chosen as governing equation in terms of temperature and displacement. The coupled equations are transferred to Laplace domain and then Galerkin finite element method is employed to solve the equation in the Laplace domain. Then, a numerical Laplace inversion has been applied to transform back the equation from Laplace domain to real time. Results are obtained for several material compositions so that the proper composition will be found for design. It is shown that FG materials (FGMs) exhibit lower stresses, lower displacement, and lower temperature levels compared to multilayer materials. Furthermore, the effect of FGM is increased by increasing the power law index, representing the change in concentration.

Thermo-Elastic Half Space Under Illumination of a Laser Beam by Using Lord and Shulman Theory

The problem of thermo-elasticity, based on the theory of Lord and Shulman with one relaxation time, is used to solve a two-dimensional boundary value problem for a semi-infinite medium heated by a pulsed laser beam. The surface of the medium is taken as traction free. The general solution is obtained in the Laplace and Hankel transforms domain. Approximate small time analytical solutions to temperature, displacement, and stress are obtained. Results of this problem are presented graphically.

Thermo-Elastic Dissipation of Microbeam Resonators in the Framework of Generalized Thermo-Elasticity Theory

Thermo-elastic dissipation of microbeam resonators is studied by the generalized thermo-elasticity theory of Lord and Shulman's model. Explicit formulae of thermo-elastic damping and frequency shift have been derived. Influences of the beam height and aspect ratio are examined. The thermal relaxation time is determined by Chester's formula, where the phonon velocity is replaced by the flexural wave velocity in the microbeam. Numerical results show that the discrepancy between results of the present non-Fourier theory and classical ones increase with decrease of aspect ratio of the beam resonator. For fixed aspect ratios thermo-elastic damping tends to increase from lower vibration modes to higher modes.

Theories of thermal stresses based on space–time-fractional telegraph equations

The generalized telegraph equations with time- and space-fractional derivatives are considered. The corresponding theories of thermal stresses are formulated. The proposed theories interpolate the classical thermoelasticity, the theory of Lord and Shulman, thermoelasticity without energy dissipation of Green and Naghdi, and theories of fractional thermoelasticity proposed earlier. The fundamental solution to the nonhomogeneous space–time-fractional telegraph equation as well as the corresponding thermal stresses are obtained in the axisymmetric case.

Dynamic problem of generalized thermoelastic diffusive medium

The equations of generalized thermoelastic diffusion, based on the theory of Lord and Shulman with one relaxation time, are derived for anisotropic media with rotation. The variational principle and reciprocity theorem for the governing equations are derived. The propagation of leaky Rayleigh waves in a viscous fluid layer overlying a homogeneous isotropic, generalized thermoelastic diffusive halfspace with rotating frame of reference is studied.

Generalized Theory of Thermoelastic Diffusion for Anisotropic Media

The equations of generalized thermoelastic diffusion, based on the theory of Lord and Shulman with one relaxation time, are given in anisotropic media. A variational principle for the governing equations is obtained. Then we show that the variational principle can be used to obtain a uniqueness theorem under suitable conditions. A reciprocity theorem for these equations is given. The obtained results are valid for some special cases that can be deduced from our generalized model.

Uniqueness and Reciprocity Theorems in the Theory of Generalized Thermoelastic Diffusion

The equations of generalized thermoelastic diffusion, based on the theory of Lord and Shulman, are given. Using Laplace transforms, a uniqueness theorem for these equations is proved. Also, a reciprocity theorem is obtained.

A generalized thermoelastic diffusion problem for an infinitelylong solid cylinder

The theory of generalized thermoelastic diffusion, based on the theory of Lord and Shulman, is used to study the thermoelastic‐diffusion interactions in an infinitely long solid cylinder subjected to a thermal shock on its surface which is in contact with a permeating substance. By means of the Laplace transform and numerical Laplace inversion the problem is solved. Numerical results predict finite speeds of propagation for thermoelastic and diffusive waves and the presence of a tensile stress region close to the cylinder surface. The problem of generalized thermoelasticity has been reduced as a special case of our problem.

A generalized electromagneto-thermoelastic problem for an infinitely long solid cylinder

The theory of generalized thermoelasticity, based on the theory of Lord and Shulman with one relaxation time, is used to study the electromagneto-thermoelastic interactions in an infinitely long perfectly conducting solid cylinder subjected to a thermal shock on its surface when the cylinder and its adjoining vacuum is subjected to a uniform axial magnetic field. The cylinder deforms because of thermal shock, and due to the application of the magnetic field, there result an induced magnetic and an induced electric field in the cylinder. The Maxwell's equations are formulated and the generalized electromagneto-thermoelastic coupled governing equations are established. By means of the Laplace transform and numerical Laplace inversion the problem is solved. The distributions of the considered temperature, stress, displacement, induced magnetic and electric field are represented graphically. From the distributions, it can be found the electromagnetic-thermoelastic coupled effects and the wave type heat propagation in the medium. This indicates that the generalized heat conduction mechanism is completely different from the classic Fourier's in essence. In generalized thermoelasticity theory heat propagates as a wave with finite velocity instead of infinite velocity in medium.

A two-dimensional generalized thermal shock problem for a half-space in electromagneto-thermoelasticity

The theory of generalized thermoelasticity, based on the theory of Lord and Shulman with one relaxation time, is used to study the electromagneto-thermoelastic interactions in a semi-infinite perfectly conducting solid subjected to a thermal shock on its surface when the solid and its adjoining vacuum is subjected to a uniform axial magnetic field. The solid deforms because of thermal shock, and due to the application of the magnetic field, there result an induced magnetic and an induced electric field in the solid. The Maxwell's equations are formulated and the generalized electromagneto-thermoelastic coupled governing equations are established. Based on these governing equations, the generalized electromagneto-thermoelastic coupled finite element equations are first formulated in this paper. By means of the Laplace transform and numerical Laplace inversion the problem is solved. The distributions of the considered physical variables are represented graphically. From the distributions, it can be found the electromagnetic-thermoelastic coupled effects and the wave type heat propagation in the medium. This indicates that the generalized heat conduction mechanism is completely different from the classic Fourier's in essence.

State space approach to one-dimensional thermal shock problem for a semi-infinite piezoelectric rod

The theory of generalized thermoelasticity, based on the theory of Lord and Shulman with one relaxation time, is used to solve a boundary value problem of one-dimensional semi-infinite piezoelectric rod with its left boundary subjected to a sudden heat. The governing partial differential equations are solved in the Laplace transform domain by the state space approach of the modern control theory. Approximate small-time analytical solutions to stress, displacement and temperature are obtained by means of the Laplace transform and inverse transform. It is found that there are two discontinuous points in both stress and temperature solutions. Numerical calculation for stress, displacement and temperature is carried out and displayed graphically.

On the propagation of thermoelastic waves in temperature rate-dependent materials

The one-dimensional propagation of thermoelastic waves in isotropic homogeneous half spaces within the theory of Green and Lindsay [1] is studied. Pade-extended ray methods are employed to obtain the desired information. Comparisons between the predictions of the Green and Lindsay theory and the theory of Lord and Shulman [2] are made. Our ray series solutions show that for discontinuous thermal disturbances the displacement according to the Green and Lindsay theory is also discontinuous. This violates the fundamental continuum hypothesis that matter is impenetrable. For a simple numerical example we show also that a compressive behaviour in the displacement may be associated with a tensile behaviour in the stress and vice versa. This prediction of the Green and Lindsay theory is also unrealistic from the physical point of view.

GENERALIZED MAGNETOTHERMO ELASTIC WAVES IN AN INFINITE ELASTIC SOLID WITH A CYLINDRICAL CAVITY

In this article, we deal with the application of generalized thermoelasticity, based on the theories of Lord and Shulman and of Green and Lindsay, to solve a one-dimensional problem related to magnetothermoelastic waves produced by a thermal shock in an infinite elastic solid with a cylindrical cavity. Laplace transform technique is employed to solve the set of basic equations. Analytical results are presented in the case of generalized thermoelasticity. Approximate small-time solutions are obtained in each case. Numerical results for displacement, temperature, and stresses are presented in the form of tables.

On Fixed and Fluid 'Texts': The Singer of Tales and the Natural Approach of Tracy D. Terrell

Before sharing with you some reflections on teaching with the Natural Approach, it might be worthwhile to review very briefly some basic operating principles of this methodology. One of the early formulators of the Natural Approach, Tracy D. Terrell, has singled out the following primary considerations: 1) immediate communicative competence [not grammatical perfection] should be the goal of beginning instruction; 2) instruction should be directed to modifying and improving the students' grammar [rather than building it one rule at time]; 3) students should be given the opportunity to acquire [rather than be forced to learn it]; and 4) affective [not cognitive] factors are primary forces operating in acquisition ['A Natural Approach 329].1 I should also like to establish the context of the fixed text and the fluid text appearing in the title. A fixed text, or classroom agenda, is one in which the material to be learned is taught in isolation (fragmented from the system as whole) or within rigid boundaries. Conversely, the fluid text would designate manner of presenting the same material which would permit those boundaries to expand and perhaps even dissolve, while keeping acquisition anchored in the system as whole. The framework for these comments is as much Albert B. Lord's The Singer of Tales as it is Tracy Terrell's formulations of the Natural Approach. To my knowledge, Lord's important little book has never before been associated with teaching methodology; yet, Lord's landmark study of techniques for composition among unlettered singers of Yugoslavia and other South Slavic regions certainly is an exposition of highly refined methodology. That methodology relates very specifically to acquisition and mastery with one significant difference: the language studied by Professor Lord is the unique to epic verse-making by the use of formulae. Lord's theory of composition during performance is an extension of the work of his Harvard mentor, Milman Parry, and is founded on Parry's definition of the formula as a group of words which is regularly employed under the same metrical conditions to express given essential idea (Lord 4). The way in which the poet uses formulae in the of composing in performance is unique and prodigious in which oral composition and transmission almost merge; they seem to be different facets of the same process (5). This observation lends itself to some of the most successful learning techniques that we use in the classroom which are perceived by the studentconsciously or unconsciously-to be different facets of the same process. The student, after all, is learning language. The student is not in our classroom to cover ser and estar, the uses of the subjunctive, irregular future stems, etc. Rather, s/he is there to learn system which most commercial texts have broken

GENERALIZED THERMOELASTICITY IN AN INFINITE SOLID WITH A HOLE

This paper deals with one-dimensional generalized thermoelasticity based on the theories of Lord and Shulman and of Green and Lindsay. A formulation of generalized thermoelasticity that combines both generalized theories is derived. The generalized thermoelastic problems for an infinite solid with a cylindrical hole and an infinite solid with a spherical hole are analyzed by means of the Laplace transform technique. Numerical calculations for temperature, displacement, and stresses under the generalized formulation are carried out and compared with those of classical dynamic coupled theory.