bluuebunny/crossref_metadata_2025 huggingface dataset:
An Exact Approach for Free Flexural Vibrations of Multistep Nonuniform Beams
Authors: Li Q.S.
Published: March 2007

A new exact approach that combines the general solutions and recurrence formula developed in this paper for determining natural frequencies and mode shapes of multistep flexural beams with varying cross sections is proposed in this paper. The frequency equations of such beams with several concentrated masses, rotational springs, and translational springs at the ends and intermediate points can be easily established from a determinant of order two. The general solutions for free vibrations of five classes of nonuniform beams are found and expressed in terms of Bessel functions, triangular functions, and hyperbolic functions. Numerical examples show that the calculated natural frequencies and mode shapes are very close to the corresponding field measure data, and the proposed procedure is a simple, efficient, and exact method.
Time-Domain Simulations of Linear and Nonlinear Aeroelastic Behavior
Authors: Preidikman Sergio , Mook Dean
Published: March 2007

A method for simulating unsteady, nonlinear, subsonic aeroelastic behavior of an aircraft wing is described. The flowing air and deforming structure are treated as the elements of a single dynamic system, and all of the governing equations are integrated numerically, simultaneously, and interactively in the time domain. The authors' version of the general nonlinear, unsteady, vortex-lattice method is used to predict the aerodynamic forces; a linear finite-element model of the wing, which is derived from MSC/NASTRAN, is used to predict the deformations of the wing; and the models are coupled in such a way that the structural and aerodynamic grids can be chosen arbitrarily. The deformation of the wing is expressed as an expansion in terms of the linear free-vibration modes obtained from the finite-element model, and the time-dependent coefficients in the expansion serve as the generalized coordinates for the entire dynamic system. A predictor- corrector method is adapted to solve for the generalized coordinates and the flowfield. The results clearly show that when the speed is low, the responses to initial disturbances contain many frequencies and decay, but that the responses become more organized (energy concentrates around a few frequencies) as the speed and/or the angle of attack increases. Finally, at the onset of flutter, all of the modes, after an initial transient period, respond at the same frequency. It appears that the flutter-causing instability is a supercritical Hopf bifurcation. At and above the critical speed, the amplitudes of the responses appear to grow linearly with time initially, but then become limit cycles. The amplitudes of the limit cycles grow as the speed increases, and eventually it appears that the limit cycles experience a secondary supercritical Hopf bifurcation and become unstable; their amplitudes and phases modulate. At this point, the response can be described as motion on a torus.
Stochastic Optimal Bounded Control for a System With the Boltz Cost Function
Authors: Iourtchenko D.V.
Published: March 2007

A single-degree-of-freedom mass-spring system is considered under white-noise excitation. To reduce expected response energy of the system, a bounded control force can be applied and optimal control law is sought for. An exact explicit analytical solution, for the Lagrange cost function, is derived for the Hamilton-Jacobi-Bellman (HJB) equation within a certain "outer" domain. This solution provides boundary conditions for numerical simulation of the HJB equation within the remaining "inner" domain. Comparison of optimal control law, with a previously obtained one for the Mayer cost function, is made. The analytical solution to the HJB equation for the "combined" Boltz cost function is derived for the outer domain as a linear combination of the solutions for the Mayer and Lagrange cost functions. Sensitivity of the Bellman functional to the above optimal control laws is analyzed.
Prediction of the Steady State Dynamic Behavior of an Elastically Supported Rigid Plate Subjected to a Steady Uniform Airflow
Authors: Al-Saif K.A. , Al-Majed M.I.
Published: March 2007

The steady state dynamic behavior of an autonomous nonconservative system is investigated both numerically and experimentally. The system consists of an elastically supported rigid plate and is subjected to a uniform steady airflow. The plate is allowed to execute large rotational oscillations. Therefore, the flow separates and reattaches as the plate oscillates. Modeling the motion-dependent fluid forces using the unsteady Navier-Stokes equations coupled with the structural equations is a very formidable task and requires an immense amount of computations. An alternative approach to model the solid-fluid interaction is presented. The model is improved based on the measured time histories of the plate motion. The refined mathematical model is used to predict the steady state frequency of the plate vibration. Another objective of the current study is to develop empirical equations to predict the critical flow speed that initiates the plate vibration as well as the self-excited frequency of the plate oscillations. The equations include all the relevant parameters of the system. The developed equations are then verified experimentally. A good correlation between the predicted and the tested results is achieved.
Bifurcation in a Flexible Rotor Supported by Short Journal Bearings With Nonlinear Suspension
Authors: Chen Cha'o-Kuang , Yau Her-Terng
Published: March 2007

The hydrodynamic journal bearings-rotor system is a common machine element that is strongly nonlinear due to oil film forces. In this study, bifurcation of the response of an unbalanced bearings-rotor system with nonlinear suspension is investigated based on the assumption of an incompressible lubricant to gether with the short bearing approximation. Theoretical bifurcation analysis of bearing center motion is carried out by means of numerical investigation, the procedure here being numerical integration. The six ma jor parameters characterizing the theoretical model of the system are considered with nondimensional speed. Jump phenomena, subharmonic and quasi-periodic vibrations of the bearing center trajectory, are found in this system. It is concluded that the bearing center trajectory had undesirable nonsynchronous vibrations. Under standing the bifurcation behavior of these parameters provides theoretical and practical ideas for controlling bearings-rotor systems and optimizing their operation.
Basins of Attraction and Transient Chaos in a Gear-Rattling Model
Authors: de Souza Silvio L.T. , Caldas Iberê L.
Published: March 2007

The authors numerically investigate basins of attraction of coexisting periodic and chaotic attrac tors in a gear-rattling impact model. These attractors are strongly dependent on small changes of the initial conditions. Gradually varying a control parameter, the size of these basins of attraction is modified by global bifurcations of their boundaries. Moreover, the topology of these basins is also modified by appearance or disappearance of coexisting attractors. Furthermore, for the considered control parameter range, the frac tal basin boundaries are so interleaved that trajectories are practically unpredictable in some regions of phase space. The authors also examine an example of a crisis on which a chaotic attractor is converted into a chaotic transient that goes to a periodic attractor. For this crisis, the authors show the evolution of transient lifetime dependence of the initial conditions as the control parameter is varied.
Calculus Model for a Rolling Guided Missile
Authors: Botez R.M. , Chelaru V. , Parvu P. , Gheorghe C.
Published: March 2007

The paper presents the relations that form the basis for the calculus models needed to study rolling guided missiles. The equations of the general motion are written within the Resal trihedral in a way that allows, after linearization, one to draw up a structural scheme of the controlled object, a scheme that will be used in the guided missile system analysis. Opposite to the flying machines with stabilized roll where the analysis is done after decoupling the channels, for the missile with rotation, the analysis of the scheme is done simultaneously on both channels, as terms used are complex terms. Furthermore, there will be presented some characteristics of this type of missile by analyzing a model close to the one of an antichariot missile with gasodynamic control.
Free Vibration of Skewed Bridges
Authors: Maleki S.
Published: March 2007

Determination of period of vibration is an essential step in understanding the seismic behavior of bridges. In this paper, an analytical solution for the free vibration problem of slab-beam, single-span skewed bridges is derived. It is assumed that the deck acts as a rigid diaphragm, but the effects of cross-frame and elastomeric bearing stiffnesses at the ends of the span are included. Based on the ratio of elastomer to cross-frame stiffness, exact equations for determination of translational and torsional periods of vibration and their corresponding mode shapes are derived. In addition, correlation factors for estimating the translational periods of a skewed bridge from the periods of a straight bridge with the same characteristics are also given. The derived equations are compared with finite element analysis, and it is shown that they are in excellent agreement.
Instability Mechanisms of a Centrally Clamped Rotating Circular Disk Under a Space-Fixed Spring-Mass-Dashpot System
Authors: Manzione Piergiuseppe , Nayfeh Ali H.
Published: March 2007

The transverse vibrations of a circular disk of uniform thickness rotating about its axis with constant angular velocity are analyzed when the disk is subject to a space-fixed spring-mass-dashpot system. The disk is clamped at the center and free at the periphery. Using the method of multiple scales, the authors determine a set of four nonlinear ordinary-differential equations governing the modulation of the amplitudes and phases of two interacting modes. The symmetry of the system and the loading conditions are reflected in the symmetry of the modulation equations. They are reduced to an equivalent set of two first-order equations whose equilibrium solutions are determined analytically. The stability characteristics of these solutions is studied; the qualitative behavior of the response is independent of the mode being considered. Considering the case of a spring moving periodically along the radius of the disk, the authors show how its frequency can be coupled to the rotational speed of the disk and subject the system to a principal parametric resonance.
Filtering of Rayleigh Surface Waves by Means of Periodic Corrugations
Authors: Asfar Omar R. , Hawwa Muhammad A.
Published: March 2007

Using a periodic corrugation at the surface of a semi-infinite elastic medium, the incident and reflected Rayleigh modes are strongly coupled when the Bragg condition is satisfied. The method of multiple scales is used to derive the coupled-mode equations describing such an interaction. The filter response is presented in terms of the reflection coefficient. An improved filter response may be obtained by imposing an amplitude taper on the corrugation, resulting in a close to ideal narrower midband response. By further introducing a chirped corrugation, an optimized wider midband response is realized.
Chain Link Deformation in the Nonlinear Dynamics of Tracked Vehicles
Authors: Sarwar M.K. , Nakanishi Toshikazu , Shabana A.A.
Published: March 2007

In this investigation, a computational finite element procedure for the deformation and stress analysis of the chain links of tracked vehicles is presented and used to examine the validity of using the static approach in the design and stress analysis of tracked vehicles. The contact forces resulting from the interaction between the track links and the vehicle components (sprocket, idler, and the rollers) as well as the interaction between the track links and the ground are evaluated using continuous force models, which are used to define generalized contact forces associated with the deformation degrees of freedom of the track links using the virtual work. The dynamic forces including the contact forces used in the finite element procedure developed in this investigation are evaluated using a 54-body vehicle model in which the track is modeled as a closed kinematic chain with 42 degrees of freedom. It is demonstrated in this study that the effect of the contact forces is more significant as compared to the effect of the rigid-body inertia forces of the chain links, and consequently, it is assumed that the deformation of the track links does not have a significant effect on the overall motion of the vehicle. In the finite element computational procedure used in this study, three-dimensional solid elements are used to discretize the links of the track chain. The numerical results presented in this investigation demonstrate that the use of the static analysis may lead to low estimates of the stresses of the track links as compared to those obtained by a dynamic stress analysis that takes into consideration the time history of the forces.
Dynamics of Multibody Systems Containing Dependent Unilateral Constraints with Friction
Authors: Wösle M. , Pfeiffer F.
Published: March 2007

In couplings of machines and mechanisms, backlash and friction phenomena are always occurring. Whether stick-slip phenomena take place depends on the structure of such couplings. These processes can be modeled as multibody systems with a time-varying topology. Making use of Lagrange multiplier methods with a mathematical formulation of the contact problem is very efficient for large systems with many constraints. The differential-algebraic equations of a system are transformed into a resolvable mathematical form by means of contact laws. In the following, rigid multibody systems with dependent constraints and planar friction will be considered. For the evaluation of such problems, an iterative algorithm is presented. This method is based on transformations of the kinematic secondary conditions in the form of inequalities to equations. In mathematical sense, these transformations are projections of the constraint forces on convex sets. Ultimately, we have a solvable nonlinear system of equations consisting of the differential equations of motion, the constraint equations and the projections of the constraint forces.
Natural Frequencies of Near-Periodic Structures
Authors: Masad Jamal A.
Published: March 2007

An approximate analytical expression for the natural frequencies of a multi-degree of freedom sys tem with small deviations in its masses and stiffnesses from some mean values is presented. The expression is derived by using the method of strained parameters along with the adjoint of the perfectly periodic struc ture problem. Numerical examples for linearly decreasing masses and stiffnesses are considered where the approximate values of the natural frequencies are compared with the corresponding exact values.
Explicit Stability Conditions For Viscoelastic Structural Members
Authors: Drozdov A.D. , Kalamkarov A.L.
Published: March 2007

For a linear viscoelastic system, the authors derive sufficient stability conditions formulated ex plicitly in terms of the system coefficients. These conditions are determined by two parameters of relaxation kernels. The first is the standard norm of the kernel. The other characteristic (maximum of the norm for the Laplace transform of the relaxation kernel) is newly developed. To demonstrate efficiency of these conditions, the authors apply them to two problems of practical interest. The first example is concerned with a system of two bars (elastic and viscoelastic) linked by a thin adhesive layer. The viscoelastic bar is compressed, and the elastic bar is stretched. Explicit restrictions on the compressive load are developed that ensure the system stability. Dependence of the critical compressive force on the tensile load and on the material parameters is analyzed numerically.The other problem is concerned with flutter of a viscoelastic compressed panel in a supersonic gas flow. Explicit restrictions on the compressive load and on the gas speed are derived for an arbitrary relaxation kernel of the panel material. Dependence of the critical flow speed on the material viscosity is studied numerically.
Semiactive and Active Suspensions for Vehicle Ride Control Using Velocity Feedback
Authors: Lieh Junghsen
Published: March 2007

This paper discusses the application of velocity feedback systems to the control of vehicle ride. The first is a semiactive damper with an adjustable damping coefficient. The damping may be switched from low to high or vice versa through continuous paths. The second is an active damper whose control force is derived from velocity signals. Both control systems could be used when full-state information is not available. The effect of high damping levels and control valve switching time of the semiactive damper on the ride performance is examined. The controller for the active damper is developed from second-order equations. By assuming the road profile as a random noise, the power spectral density is computed and compared with that of full-state systems. A quarter-car model is used for the simulation.
Optimal Sensor Deployment: Application to Model Updating
Authors: Lallement G. , Ramanitranja A. , Cogan S.
Published: March 2007

The proposed formulations deal with various specific aspects of the problem of parametric identi fication of linear elastodynamic finite element models. They involve adapting, via expansion data observed on the structure, to the analogous quantities calculated from the model. They also aim at improving the condition number of the estimation equations. The minimization of expansion errors in frequency responses or eigenvectors by an optimal choice of the observed dofs is formulated in two cases: the first uses a Ritz basis consisting of eigenvectors and static residuals, while the second implies using a Guyan-static condensation matrix. The relationship between optimal expansion and maximization of the cutoff frequency corresponding to this condensation is also analyzed.
On Harmonic Vibrations in Thermoelasticity of Micropolar Bodies
Authors: Marin M. , Lupu M.
Published: March 2007

In this study, the authors consider a right cylinder composed of a physically micropolar thermoelastic material for which one plane end is subjected to an excitation harmonic in time. By using a measure of Toupin type associated with the corresponding steady-state vibration and assuming that the exciting frequency is lower to a certain critical frequency, the authors obtain a spatial decay estimate, similar to that of the Saint-Venant type.
A Case Study of the Generation of Irregular Sea Waves
Authors: Nohara Ben T.
Published: March 2007

This article describes the generation methods of irregular sea waves specified by its spectrum. It will describe the difference between the small equal frequency division method and the energy equivalence frequency division method. In the latter method, it is shown to completely generate a stationary irregular wave in an engineering regard. The theoretical iteration period of the time histories generated by the method is also obtained by using a symbolic computation. Finally, experimental results of the generation of sea waves spectra are presented. The spectrum of the revolution of the AC servomotor driven by the energy equivalence frequency division method is obtained. The good agreement between the measured and calculated spectra is shown.
Tension-Induced Conveyor Belts: A Finite Element Free Vibration Study
Authors: Samanta A. , Mukhopadhyay M.
Published: March 2007

A conveyor belt is often analyzed for free vibration by considering a panel of it that may yield results that are misleading. To improve on the existing practice, an analysis has been carried out by treating the complete belt as a folded plate. For these belts, high tension is induced, and the belts vibrate in a flexural mode. A discrete Kirchhoff triangle (DKT) plate-bending element, in combination with Allman's plane stress triangle, has been used to carry out the necessary finite element analysis. Free vibration study has been carried out for three different belt shapes. Results have been compared when available. Although scanty literature is available on the free vibration of folded plates, no investigation has yet been reported so far on folded plates with in-plane forces, which occurs in the case of conveyor belts. Results for these cases are presented for the first time.
Recommended Control Configurations for DC Drives With Flexible Shafts
Authors: Yousef H.A. , El-Saied S.M. , Sebakhy O.A.
Published: March 2007

This article deals with new recommended control structures for adjustable-speed direct current (DC) drives with a flexible shaft. Two cases will be analyzed: a two-inertia system (i.e., single motor driving a load through an elastic coupling; e.g., suction fan drive) and a three-inertia system (i.e., two motors driving a common load through two elastic couplings; e.g., dual-kiln drives). The first recommended control con figuration is an extension of the rigid system controller with an added control term that is proportional to the differential speed. The second recommended configuration is the variable-structure sliding-mode con trol (VSC) that is known to be robust, insensitive to parameter variations, and easy to implement. Simulation results for both structures are presented to illustrate the effectiveness of the proposed controllers.
On the Isolation Properties of Semiactive Dampers
Authors: Ahmadian Mehdi
Published: March 2007

The primary purpose of this study is to evaluate and better understand the isolation properties of semiactive suspensions. Specifically, this study will answer the question regarding why semiactive dampers are able to isolate at frequencies well below those for passive dampers, even though they do not add any energy to the system. A single suspension model is used to derive and analytically evaluate the transmissibility properties of passive and semiactive dampers. The results show that for semiactive dampers, the frequency range of isolation and the transmissibility amplitude are functions of ξ, the damping ratio. In contrast, the isolation frequency range for passive dampers is completely independent of ξ. Furthermore, the results show that for sufficiently large ξ, semiactive dampers are able to provide isolation at all frequencies. This feature is useful for many applications, particularly for sensitive machinery that cannot tolerate any overshoot in power- up or power-down, and yet must have good isolation during normal operation. Passive suspensions offer only one of the two aspects, whereas semiactive suspensions offer both.
An Application of Smart-Structure Technology to Rotor Blade Tip Vibration Control
Authors: Lin Y.-J. , Lee T. , Choi B. , Saravanos D.
Published: March 2007

This paper presents the experimental development of a simple and effective vibration control scheme by employing smart-structure technology Due to high accuracy and high slew rate requirements for lightweight structures, vibration control becomes a challenging task. In this paper, it is proposed to ac tively control rotor blade tip vibration with collocated piezoceramic sensors and actuators. To include the flexible characteristics of rotor blades in the analysis, a flexible cantilever beam is used to simulate the dy namic behavior of the blade subjected to external disturbances, generated by a magnetic shaker. The shaker was installed near the tip of the simulated rotor blade to maximize the external excitations. PZT4 piezoce ramic sensor and actuator were used and considered as elements of the smart structure. Based on the derived dynamic model, a proportional gain feedback controller was implemented to compensate for the vibratory de flections of the underlying structure. The results of the work show that the proposed control methodology along with the smart structure can suppress 85% of the measured structural vibration, which is considered satisfactory.
Optimal Actuator Placement for Active Vibration Control With Known Disturbances
Authors: Mirza Marghub Alam , Van Niekerk Johannes L.
Published: March 2007

Two cost functions, based on the disturbance sensitivity grammian, are presented that can be used to find the optimal position of an active vibration control actuator. The disturbance sensitivity grammian is a novel parameter in the field of active vibration control, and by minimizing the "size" of this matrix, one can maximize the effectiveness of the actuator to control the structure in a closed-loop configuration. Two examples—a pinned-pinned beam and an L-shaped membrane—are used to demonstrate the applicability of the criterion. It turns out that the optimal position is very close to where the disturbance acts on the system. The criterion is also not sensitive to the assumed damping included in the model.
Nonlinear Longitudinal Vibrations of a Rod
Authors: Cveticanin L. , Uzelac Z.
Published: March 2007

This paper deals with the longitudinal vibrations of a nonlinear rod. The nonlinearity is strong and of cubic type. The motion of the rod is described by a second-order strong nonlinear partial differential equation. The exact numerical solution is obtained. Four approximate analytical methods for solving the differential equation are developed: the eigenmode solutions are denoted by applying the known space or time distribution functions, respectively, the method based on invariant manifolds, and the method for optimizing the two-mode eigenfrequency solution. The analytical and numerical solutions are compared. The amplitude-time-position diagrams and amplitude-frequency diagrams are plotted.
Theory and Vibration Analysis of Laminated Barrel Thin Shells
Authors: Qatu Mohamad S.
Published: March 2007

This paper deals with analysis of laminated composite barrel shells. Barrel shells are essentially cylindrical shells for which the meridional direction of the shell has some initial curvature. The curvature may be due to imperfection in manufacturing, or is a part of the design as is the case in barrel shells. The equations are developed for the general dynamic analysis of laminated barrel shells and can be reduced to the static analysis and the free vibration analysis. Natural frequencies are obtained for open and closed, isotropic and laminated barrel shells having shear diaphragm boundary conditions. For composite shells, the effects of curvature, thickness, and orthotropy ratios as well as the lamination sequence on the nondimensional natural frequency parameters are studied.
Stability Analysis for Linear Time-Varying Systems With Uncertain Parameters: Application to Steady-State Solutions of Nonlinear Systems
Authors: Pun D. , Lau S.L. , Cao D.Q.
Published: March 2007

The problem of robust stability in the state space model of linear time-varying systems with time- varying parameter uncertainties is considered. The Lyapunov approach is employed to obtain bounds on the uncertain time-varying parameters to guarantee the stability of the system. The robust stability bounds obtained are not necessarily symmetric with respect to the origin in the parameter space and can significantly reduce the conservatism in the previous results. Sufficient conditions for the stability of the steady-state responses of nonlinear systems (especially of piecewise linear systems) subjected to periodic excitations are proposed by using the results derived. Two numerical examples are used to demonstrate the accuracy of the formulation.
The Key Role of Listening in Business: A Study of the Singapore Insurance Industry
Authors: Goby Valerie Priscilla , Lewis Justus Helen
Published: March 2007

We tend to regard listening as a passive, automatic process that just happens rather than as a skill that is essential for good communication. Yet in reality effective lis tening is a skill that needs to be developed as a prerequisite for successful practice of the more 'active' skills of speaking and writing. The insurance industry is a prime example of an industry that relies heavily on good listening skills for effective marketing. We conducted a study in Singapore of how listening is perceived by people involved in insurance. We found that more experienced people were well aware of its key role although students majoring in insurance believed speaking was more important. This study confirms earlier research: in the insurance indus try in Singapore there is a gap between the perceived need for good listening and the degree to which good listening skills are perceived to be possessed by insurance agents.
Building Knowledge Structures in Teaching Cross-cultural Sales Genres
Authors: Yunxia Zhu
Published: March 2007

Approaching genres as knowledge structures provides a useful theoretical basis for teaching students to communicate across cultures. The approach is based on the concept of schemata (Rumelhart, 1980; Cook, 1994) and on Swales's (1990) techniques for genre analysis. It is divided into four interrelated teaching stages: background information, communicative purposes, text structure, and the implica tions of genre comparisons. Among the four stages, teaching the communicative purposes is the most important. This approach has been used effectively to teach students how to write sales letters in English and Chinese.
Self-observation in Teaching: what to Look for
Authors: Robbins Larry
Published: March 2007

Instructors who want to improve their teaching often do not know how to identify the changes they need or want to make. This article offers practical suggestions on course planning and class preparation, effective communication, questioning and responding, assessment and evaluation. The focus is on providing a method of observing the process of teaching and learning. If teachers know how to observe themselves, they can more easily establish a personal style that motivates their students.
Toward a New Cartography of Intercultural communication: Mapping Bias, Business, and Diversity
Authors: Munshi Debashish , McKie David
Published: March 2007

Courses in intercultural communication often put non-Western students at a dis advantage. In developing a course with a majority of non-Western participants at The University of Waikato, we adapted critical pedagogy to address the Western biases in the texts and approaches of intercultural communication. We selected both mainstream and alternative readings that allowed students to connect the field's neo-colonial business present with its colonialist past, to question the ethics and efficacy of an often skewed territorialisation of knowledge; and to redress tra ditional distortions by introducing perspectives from a range of critical and post colonial theorists. The readings were reinforced by student presentations of their own experiences crossing cultural borders. These experiences were then assessed in class, so that we didn't rely on the simulated experiences recorded in the conven tional texts.
Language Training for Enhanced Horizontal Communication: A Challenge for MNCs
Authors: Charles Mirjaliisa , Marschan-Piekkari Rebecca
Published: March 2007

Horizontal communication between subsidiaries of the same multinational corpo ration (MNC) is a Problem faced by staff as the demands for communicating across borders are pushed downwards in the organizational hierarchy. Although the choice of English as the common corporate language alleviates some of the hor izontal communication problems, it does not solve them all-particularly not when many subsidiaries are located in non-English speaking countries. In that situation, horizontal communication between subsidiaries can be a significant casualty.

In a study of communication within a Finland-based MNC, Kone Elevators, interviews with staff globally revealed problems not only for non-native speakers, but also for native speakers of English. Illustrative interview data suggests that cor porate training schemes should focus on the broad spectrum of international com munication rather than on increasing a systematic knowledge of any one language.
From "Acing the Test" to "Touching Base": The Sports Metaphor in the Classroom
Authors: Offstein Evan H. , Neck Christopher P.
Published: March 2007

The use of sports metaphors to convey business lessons both within and outside the classroom is a common phenomenon. The sports metaphor, however, is prone to misuse and can often inadvertently exclude large segments of the student popula tion. To address these issues, we put forth an innovative and novel pedagogical approach that attempts to capitalize better on the shared meanings between athlet ics and certain business practices. Using the sports of tennis and basketball, we demonstrate how sports metaphors can he responsibly used to aid in the under standing of business lessons, such as managerial decision making.
Getting the Big Picture: Writing to Learn in a Finance Class
Authors: Hall Susan , Tiggeman Theresa
Published: March 2007

This paper describes a project incorporating writing-to- learn activities into an introductory finance class. Such activities use writing informally as a vehicle to promote student learning. Examination of the students' brief papers showed that students became less likely to skip theory and go to canned formulas and that they took more responsibil ity for their work. For instructors, the project was beneficial because it enabled them to tailor class presentations more precisely to students' actual comprehension of course material.
The Writing of Nurse Managers: A Neglected Area of Professional Communication Research
Authors: Spears Lee A.
Published: March 2007

The practice and teaching of nurse management writing has received little attention in professional communication journals. This study is based on sec ondary research, examination of documents written by nurse managers, and interviews with 54 nurse managers and 13 nurse educators. It indicates that writing a variety of business communications is a crucial career task jor nurse managers, directly affecting their professional power. However, most nurse managers interviewed believed their undergraduate education had not pre pared them adequately for their workplace writing and perceived a need for professional writing instruction in four-year nursing programs.
New Corporate Practice, New Classroom Pedagogy: Toward a Redefinition of Management Communication
Authors: Rubin James R.
Published: March 2007

Just as the challenge in a global economy is to develop new frameworks and then communicate them effectively, our challenge is to prepare students for negotiating wholly new communication challenges. Communication is much more than expressing the content of other "real" business disciplines clearly. Language and image have become a crucial part of creating and managing contemporary corporate culture; thus, we must expand the teaching of man agerial communication to include corporate communication. To describe "communication," we must also employ words such as "critical thinking" and "flexibility." Communication is integral to the process of problem solving in the team-oriented workplace.
Preparing MBA Students for the World of Professional Communication
Authors: Wolff Aline
Published: March 2007

An analysis of a large-scale professional communication project helps to define relevant managerial communication tasks; the project exemplifies the type of projects that graduating students will be expected to collaborate on or to manage successfully. The implications of this project for teaching manager ial communication to MBA students and recommended applications for inte grating work world tasks into the curriculum are also discussed.
Human Factors in High-Tech Writing: Targeting the Right Tool for Professional Development
Authors: Rehling Louise
Published: March 2007

Practitioners, students, and instructors of business communication can benefit from learning new professional technologies; but choosing among them may be difficult. This article provides a method, based on human factors, for help ing individuals with that choice. The first step is to complete a self-assessment questionnaire ranking preferences among forms, industries, techniques, roles, and purposes for writing. Then, individuals can match those preferences to typ ical expectationsfor each of several new text technologies: structured on-line documentation markups, help screens and interactive tutorials, and multime dia presentations. With that information, individuals can choose training in a technology that suits them.
Skills Versus Apprehension: Empirical Euidence on Oral Communication
Authors: Fordham David R. , Gabbin Alexander L.
Published: March 2007

Regardless of their oral communication ability, students must be willing to use their communication skills to be successful in business professions. A pro gram of study that addresses communication skills may not satisfactorily address the apprehension students may feel about communicating. In this study we administered the Personal Report of Communication Appreliension (PRCA) to 84 accounting seniors at an institution whose curriculum requires significant communication skills training and practice. We conclude that busi ness educators must pay special attention to communication apprehension separate from, and in addition to, communication skills.
Student Perceptions of the Value of a Prewriting Problem-Solving Plan
Authors: Winter Janet K.
Published: March 2007

This study attempted to determine student perceptions of the value of using a prewriting problem-solving plan and its relationship to their success in writ ing. The business communication students in the study felt that the plan was beneficial, particularly for persuasive messages, individual writing, and small- group writing. In addition, participants seemed to feel that the plan was worth preparing even when not required as part of the assignment. The results sug gest that the problern-solving plan can be a useful tool for complicated assign ments and group work but that it should probably be optional for simple assignments.
Student and Instructor Use of Comments on Business Communication Papers
Authors: Winter Janet K. , Neal Joan C. , Waner Karen K.
Published: March 2007

Writing comments on student papers takes tremendous effort, and this study attempted to determine how students use these comments, the importance of the comments, and methods to encourage students to use comments. The results revealed that students' course grades did not correlate with their use of comments; however, students were likely to review comments if they had to rewrite assignments. Significant differences existed between course grades and these variables: (a) how well students read comments, (b) how useful com ments were, (c) how well students understood comments, and (d) how likely students were to get help in understanding comments.
Integrating Managerial Ethics into the Business Communication Curriculum
Authors: Brown Paula E. , Mausehund Jean
Published: March 2007

This article addresses the advantages of using a business structure in the classroom, the purpose of discussing ethics in the classroom, a design of a classroom business, the methodology needed to implement the activity, an assessment of outcomes, and the results of the exercise.
Does "Gramma-tik" You off?
Authors: Ray Lorraine
Published: March 2007

The effectiveness of WordPerfect's Grammatik as a tool for business writing is the sub ject of this study. Results of this informal study suggest significant limitations to the effectiveness of this application as a guide for student writ ers. I reached this conclusion by having 12 students' papers critiqued by both Grammatik (affectionately known as Gramma) and by real English/ business communication professors to compare their values.
Written Feedback on Student Assignments: Another Look
Authors: Byrne Ros
Published: March 2007

Recent articles in Business Communication Quarterly advocate giving oral feedback on business communication assignments and compare such com mentary to written feedback: Little attention has been paid, however, to computer-assisted feedback. This article describes one way to give such word- processed feedback, describes some advantages of this mode over both hand written and audio comments, and identifies some limitations of this method.
In vitro interactions between calcium, zinc, copper and iron in milk- and soy-based infant formulas / Interacciones in vitro entre calcio, cinc, cobre e hierro en formulas de base láctea y de soja para lactantes
Authors: Jovaní M. , le Masle M. , Alegría A. , Barberá R. , Farré R. , Lagarda M.J. , Clemente G.
Published: March 2007

Interactions among calcium, zinc, copper and iron in milk- and soy-based infant formulas were as sessed in order to evaluate the influence of supplementation with one trace element on the bioavailability of the others. The criterion used to estimate the bioavailability is the percentage of dialysis, estimated by applying an in vitro method. Infant formulas were supplemented with CaCl2, ZnO, CuCO3 Cu(OH) 22H2O and FeSO4 7H2O at two levels (maximum (+) and minimum (-) allowed by the European Union). A factorial design at two levels with three factors (Zn, Cu and Fe addition) was carried out. The main effects and the second-order interactions of the studied factors on the bioavailability of a given element were estimated. The results obtained for milk-based formulas clearly indicated the negative influence of iron at the high addition level (+) on the dialysis percentage of calcium, and of zinc at the high addition level (+) on its own dialysis percentage, whereas in the same type of formulas, the addition of zinc had a positive effect on the copper dialysis percentage. In soy- based formulas a negative effect of added copper (+) on its own dialysis percentage was observed. The most important second order interaction found to be significant was the negative effect of (zinc x iron) on copper dialysis in milk-based formulas.
Nota. Diferenciación de vinos tintos varietales de la Comunidad Valenciana a partir del contenido de alcoholes y polioles / Note. Differentiation of varietal red wines from Communidad Valenciana (Spain) based on their composition in terms of alcohols and polyols
Authors: Aleixandre J.L. , Lizama V. , Alvarez I. , Garcia M.J.
Published: March 2007

The composition in terms of alcohols and polyols of 44 and 49 red wines (harvested in 1994 and 1995, respectively) produced in Comunidad Valenciana (Spain) from the grape varieties Cabernet Sauvignon, Tempranillo, Monastrell and Bobal was,analyzed. Discriminant analysis revealed differences among wines, and a clear separation of the samples (90 and 98%) was obtained. The most important compo nents in the differentation of the varieties studied were isoamyl alcohol for Cabernet Sauvignon, cis- 3-hexenol and isobutyl alcohol for Tempranillo, methanol and cis-3-hexenol for Monastrell, and 2,3- butanediol for Bobal. The classification obtained by elimination of the five less significant variables was similar to the one obtained using statistical treatment of all variables (with 84% and 90% in their respective harvests).
Note. Quality evaluation of cupuaçu (Theobroma grandiflorum) purée after pasteurization and during storage / Nota. Calidad del puré de cupuaçu (Theobroma grandiflorum) después de la pasterización y durante su almacenamiento
Authors: Silva F.M. , Silva C.L.M.
Published: March 2007

Cupuaçu ( Theobroma grandiflorum ) is an Amazonian fruit with a pleasant aroma and flavor, which offers a great economic potential. Purée of cupuaçu pulp was pasteurized (70 and 90 °C), and stored for half a year at 18 and 38 °C. The pasteurization was effective in microbial and enzyme inactivation, and stabilization of the purée. Peroxidase enzyme was inactivated (polyphenoloxidase was not de tected in raw cupuaçu), some cupuaçu 'fresh notes' were lost, and the color changed slightly during pasteurization at both temperatures. Since, except for color, no significant quality differences were detected between samples processed at 70 °C and 90 °C, the pasteurization at 90 °C is recommended. The parameters that changed most during storage were the color, flavor, aroma and sugars. The purée got darker, especially at 38 °C, and the non-reducing sugars were converted into reducing sugars, while the total sugars remained constant. The final quality was determined by the storage tempera ture and not by the pasteurization temperature. The total color difference, TCD*, was well modeled by first-order reversible kinetics.
Note. Histamine production by some lactic acid bacteria isolated from ciders / Nota. Producción de histamina por algunas bacterias lácticas aisladas a partir de sidras
Authors: del Campo G. , Lavado I. , Dueñas M. , Irastorza A.
Published: March 2007

Histidine decarboxylase activity has been investigated in 23 strains of lactic acid bacteria, belonging to Oenococcus oeni, Lactobacillus brevis and Lactobacillus spp., isolated during the cidermaking process at different stages of fermentation. After 14 days at 25 °C on a semisynthetic medium supplemented with L-histidine, 13 strains were histamine producers and six of these strains were selected to study the kinetics of growth and histamine production at different temperatures. The results showed that histamine accumulation was maximal at 25 °C after 10-15 days of growth. Comparison of growth and histamine level curves demonstrated a delay time of eight days between maximal growth and the highest histamine content of the cultures.
Separation kinetics of karnal bunt (Tilletia indica) infected wheat (Triticum aestivum) grains in a fluidized bed / Cinética de separación de granos de trigo (Triticum aestivum) infectados con carbon parcial (Tilletia indica) en un lecho fluidificado
Authors: Alvarez-Ramirez J. , Vernon-Carter E.J. , Vizcarra-Mendoza M.
Published: March 2007

Infection of breadmaking wheat grains by karnal bunt ( Tilletia indica) is a common disease in north- western Mexican states, causing major economic losses. In this work, the feasibility of separating infected from wholesome wheat grains by using fluidized bed technologies was evaluated. The pro posed separation equipment was of the batch type and fluidization was attained via direct air injec tion into the grain bed. Minimum fluidization rates were determined and effects of infected grain composition in the bed were studied. The experimental results showed that the separation of infected grains was quite possible with small losses of wholesome wheat grains. A quantitative characteriza tion of the separation process was made by determining the separation kinetics from the available experimental data. Separation kinetics were shown to be useful for estimating the equipment operat ing time to attain an allowed level of grain infection, as established by the Mexican government for the commercialization of wheat.
Influence of flour, bacterial starter and breadmaking stages on total starch, sugars and low-molecular-weight dextrins/ Influencia de la harina, del iniciador microbiano y de la etapa del proceso de panificación sobre el almidón total, azúcares y dextrinas de bajo peso molecular
Authors: Martínez-Anaya M.A. , Rouzaud O.
Published: March 2007

Wheat flours and bacterial starters were used in sourdough and straight breadmaking processes. The effect of the processing stage on levels of starch, sugars and low-molecular-weight dextrins (LMWD) with degrees of polymerization (DP) 3-7 were studied. The breadmaking step and type of flour affected the majority of the variables. The type of microorganism influenced only sugar contents. In factor analysis, the first two factors correlated with LMWD and the third factor with starch. Sourdough and fermentation mainly influenced changes in LMWD; baking did not result in further differences. Sourdoughs and unfermented doughs had the greatest amounts of monosaccharides, whereas fermented doughs and breads had the highest levels of dextrins with DP 3-5. The type of wheat was more significant than the flour extraction rate in governing LMWD.