bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of heating on the stability of flow over concave walls
Authors: Garg Vijay K. , DiPrima R. C.
Published: March 2003

The effect of heating or cooling on the linear Görtler instability of the boundary layer flow over a concave wall is described using an asymptotic analysis for short-wavelength disturbances. The analysis takes account of all nonparallel flow effects in a uniform and systematic manner without making the quasiparallel flow approximation. The fluid viscosity is assumed constant while the perturbation in density is allowed to vary linearly with the perturbation in temperature. Both steady Taylor–Görtler disturbances and those that propagate downstream are considered. An analytic expression for the neutral curve is obtained. It is found that the critical disturbances are concentrated in thin viscous layers near the middle of the boundary layer; the precise location depending upon the basic velocity and temperature profiles. Heating the boundary layer destabilizes the short-wavelength disturbances and cooling does the reverse. While steady Taylor–Görtler disturbances are more unstable than those propagating downstream under the assumptions of the present analysis, the difference between the neutral stability boundaries for the two types of disturbances is decreased by heating at low Prandtl numbers and by cooling at moderate to high Prandtl numbers.
Theory of evaporation and condensation
Authors: Koffman L. D. , Plesset M. S. , Lees Lester
Published: March 2003

The theory of evaporation and condensation is considered from a kinetic theory approach with a particular interest in the continuum limit. The moment method of Lees is used to solve the problem of the steady flow of vapor between a hot liquid surface and a cold liquid surface. By incorporating the singular nature of the problem, the forms of the continuum flow profiles found by Plesset are recovered. The expression for mass flux has the form of the Hertz–Knudsen formula but is larger by a factor of 1.665. A result of the theory is that the temperature profile in the vapor for the continuum problem is inverted from what would seem physically reasonable. This paradox is significant in that it casts a shadow of doubt on the fundamental theory.
Whistler scattering from density fluctuations in magnetized plasmas
Authors: Antani S. N. , Kaup D. J.
Published: March 2003

Scattering of a coherent whistler from random density fluctuations is treated by a perturbation procedure. The attenuation length is calculated for scattering by a drift-wave type fluctuation model and is simply expressed as a function of the propagation angle in the limit where the whistler wavelength is long compared to a correlation length. For typical tokamak and space plasmas, this scattering becomes most important at larger angles.
Two-component ion distributions in tokamak hot ion plasmas
Authors: Ware A. A.
Published: March 2003

The two-component ion distribution observed with active charge-exchange measurements on the tokamak PDX are explained using the Fokker–Planck drift-kinetic equation and assuming that ion self-collisions are dominant for energy scattering. The energetic tail of the distribution, which is diffusing outwards in radius and down in energy, must retain an approximately constant effective temperature TH≡(−∂ ln f i/m∂ε)−1. The discontinuity in the slope of ln  f i is shown to be the boundary between the inward and outward diffusion parts of f i and is a form of contact discontinuity. Energy-scattering collisions with electrons or circulating beam ions, when important, modify the constancy of TH.
The spatial stability of a class of similarity solutions
Authors: Durlofsky L. , Brady J. F.
Published: March 2003

The spatial stability of a class of exact similarity solutions of the Navier–Stokes equations whose longitudinal velocity is of the form xf′(y), where x is the streamwise coordinate and f′(y) is a function of the transverse, cross-streamwise, coordinate y only, is determined. These similarity solutions correspond to the flow in an infinitely long channel or tube whose surface is either uniformly porous or moves with a velocity linear in x. Small perturbations to the streamwise velocity of the form xλg′(y) are assumed, resulting in an eigenvalue problem for λ which is solved numerically. For the porous wall problem, it is shown that similarity solutions in which f′(y) is a monotonic function of y are spatially stable, while those that are not monotonic are spatially unstable. For the accelerating-wall problem, the interpretation of the stability results is not unambiguous and two interpretations are offered. In one interpretation the conclusions are the same as for the porous problem—monotonic solutions are stable; the second interpretation is more restrictive in that some of the monotonic as well as the nonmonotonic solutions are unstable.
Bubbles rising in a tube and jets falling from a nozzle
Authors: Vanden-Broeck Jean-Marc
Published: March 2003

The shape of a two-dimensional bubble rising at a constant velocity U in a tube of width h is computed. The flow is assumed to be inviscid and incompressible. The problem is solved numerically by collocation. The results confirm Garabedian’s findings. There exists a unique solution for each value of the Froude number F=U/( gh)1/2 smaller than a critical value Fc. Here g denotes the acceleration of gravity. It is found that Fc =0.36. In addition the problem of a jet emerging from a vertical nozzle is considered. It is shown that the slope of the free surface at the separation points is horizontal for FFc. Graphs and tables of the results are included.
Behavior of the ponderomotive effect near gyroresonance
Authors: Lamb B. M. , Dimonte G. , Morales G. J.
Published: March 2003

A theoretical, numerical, and experimental study is made of the behavior of the ponderomotive effect for rf frequencies close to the particle gyrofrequency. Near gyroresonance the stopping potential is found to be small rather than infinite. The interaction is not adiabatic, and heating results both in the parallel and perpendicular directions. This behavior is explainable in terms of the finite transit time of the particle through the localized rf structure. A perturbation theory that includes finite transit time is found to be in good quantitative agreement with both the numerical study and the experimental results.
Oscillating two-stream instability of a ducted whistler pump
Authors: Kuo S. P. , Lee M. C.
Published: March 2003

A magnetically field-aligned zero-frequency mode excited together with two lower hybrid sidebands by a ducted whistler pump is investigated. The thermal focusing force is found to be the dominant nonlinear effect on the excitation of large-scale instabilities; while the nonoscillatory beating current overrides the thermal focusing force in the short wavelength instabilities. Applications of these studies to space and laboratory plasmas are discussed.
Theory of anomalous tearing mode growth and the major tokamak disruption
Authors: Diamond P. H. , Hazeltine R. D. , An Z. G. , Carreras B. A. , Hicks H. R.
Published: March 2003

An analytic theory of turbulence in reduced resistive magnetohydrodynamics is developed and applied to the major disruption in tokamaks. The renormalized equations for a long-wavelength tearing instability are derived. The theory predicts two principal nonlinear effects: an anomalous flux diffusivity due to turbulent fluid convection in Ohm’s law and a vorticity damping term due to turbulent magnetic stresses in the equation of motion. In the final phase of the disruption, when fine-scale fluid turbulence has been generated, detailed considerations show that anomalous diffusivity has the dominant effect at long wavelengths. For a low-m tearing mode, the solution of the renormalized equations during the turbulent phase yields a growth rate analogous to the classical case but increased by turbulent resistivity: γ∼(∑k′ k′2θ‖φk′‖2)3/8 ×(Δ′)1/2. This analytical prediction is in good accord with computational results.
Dependence of fast magnetic reconnection on characteristic plasma quantities
Authors: Ugai Masayuki
Published: March 2003

The fundamental fast reconnection flows in a large-scale X-type field configuration are numerically studied for various plasma conditions. The fast reconnection becomes more effective as the plasma density ρ̃ in the antiparallel-field region becomes lower, and the reconnection rate approximately scales as ρ̃−0.2, whereas it is little influenced by the plasma β. The relative electron–ion drift velocity, enhanced by the buildup of fast reconnection, becomes much larger near the X point as the plasma density or the plasma β becomes lower, which is favorable to the occurrence of anomalous resistivity. An important plasma situation where the effective fast reconnection and the significant anomalous resistivity can simultaneously grow is that the plasma density and the plasma β are sufficiently low in the ambient antiparallel-field region outside the field-reversal region.
Wave propagation in a plasma-filled bumpy cylinder
Authors: Whang K. W. , Shoji T. , Tsuboi F.
Published: March 2003

The propagation of waves with frequencies equal to or slightly less than the ion-cyclotron frequency is studied in absorptionless, uniform plasma in a bumpy cylinder. The corrugated wall is found to inhibit free propagation of the waves. The reflection coefficient is obtained by the variational method. The dispersion curve exhibits nonpropagating regions, and therefore suggests that ion-cyclotron resonance heating in bumpy tori may require many antennas for uniform toroidal heating.
Active control of transition by periodic suction-blowing
Authors: Biringen S.
Published: March 2003

A numerical study is conducted to investigate a new method of transition control by periodic suction-blowing. It is shown that significant reduction in the amplitudes of two- and three-dimensional finite-amplitude disturbances can be obtained by the application of this method to transition in plane channel flow.
Separability into coherent and chaotic time dependencies of turbulent fluctuations
Authors: Tsugé Shunichi
Published: March 2003

Theoretical background is given for the separability of turbulent unsteadiness into the coherent and the chaotic. A method of nonlinear separation of variables applied to the turbulent correlation equation yields a fluctuation equation having two temporal operators representing coherent and chaotic unsteadiness. This equation is compared with the equation of fluid dynamic stability with regard to similarity in form and difference in physical content. It is stressed that the equation is essentially complex, and that the nonlinear term representing triple correlation substantiates continuous energy cascade towards lower frequencies as well as higher ones. A Fourier transform of this equation yields a Navier–Stokes equation for variables with physical meaning distinct from the ordinary ones.
Minimum enstrophy vortices
Authors: Leith C. E.
Published: March 2003

Two kinds of minimum enstrophy vortices in two-dimensional flows are found by variational analysis. Each represents the ideal limit of a selective decay of enstrophy with energy and angular momentum or circulation, respectively, remaining fixed. For each, the vorticity is confined to a disk whose radius is determined by the fixed integrals. The definition of the vortices assures a large degree of stability, but many questions about their formation and destruction have not yet been answered.
Calculation of the spontaneous cyclotron emissivity using the complete relativistic resonance condition
Authors: Freund H. P. , Wu C. S. , Gaffey J. D.
Published: March 2003

An expression for the spectral emissivity of spontaneous synchrotron radiation for a plasma which consists of both thermal and suprathermal electron components is derived using the complete relativistic cyclotron resonance condition. The expression is valid over all angles of propagation. The result is applied to the study of the emission of radiation from an energetic population of electrons with a loss-cone distribution in a relatively low-density plasma (i.e., the electron plasma frequency is less than the cyclotron frequency).
Analysis and measurement of property disturbances in a combustion magnetohydrodynamic plasma
Authors: Simons Tad D. , Mitchner M. , Eustis R. H.
Published: March 2003

Measurements of propagating pressure and temperature (entropy) waves in a combustion magnetohydrodynamic (MHD) generator are presented along with a general model which describes how to produce controlled rapid property disturbances in a combustion MHD plasma. The model identifies the principal mechanisms of wave formation and predicts the qualitative and quantitative wave shapes as a function of average plasma and electrical properties but does not describe wave amplification. The model exhibits quantitatively the coupling between the entropy and acoustic waves and the electric current and magnetic field under conditions applicable to MHD power generation.
Electrostatic structure of the rotational discontinuity: The elementary pulse
Authors: Wang Dong-Jian , Sonnerup B. U. Ö.
Published: March 2003

An analysis is presented of the rotational discontinuity in a collision-free plasma when the width of the discontinuity is comparable to the Debye length, λD, so that a large deviation from charge neutrality occurs. It is found that such discontinuities have positive electrostatic potentials and structures similar to those of ion-acoustic solitons. The tangential magnetic field changes direction by a small angle Δθ across the discontinuity, where Δθ is of the order of λD/λi, λi being the ion inertial length. The polarization is left handed. These elementary pulse solutions exist only in a limited range of βxe and βxi values where βxe and βxi are the ratios of electron and ion pressure to magnetic pressure, the latter based on the magnetic field component Bx, normal to the layer. The possibility that rotational discontinuities with a large angle change Δθ are composed of wave trains of elementary pulses is discussed. Applications in the solar wind, at the magnetopause, and above the auroral zones are examined briefly.
Stability of the radial electric field in a nonaxisymmetric torus
Authors: Shaing K. C.
Published: March 2003

The stability of the radial electric field in a nonaxisymmetric torus is discussed from the thermodynamic point of view. It is found that for both radially local and nonlocal models, the stable radial electric field is at the minimum of the generalized heat production rate. A similarity between the local model and the liquid–gas phase transition is pointed out.
The stability of an evaporating liquid surface
Authors: Prosperetti Andrea , Plesset M. S.
Published: March 2003

A linearized stability analysis is carried out for an evaporating liquid surface with a view of understanding some observations with highly superheated liquids. The analytical results of this study depend on the unperturbed temperature near the liquid surface. The absence of this data renders a comparison with experiment impossible. However, on the basis of several different assumptions for this temperature distribution, instabilities of the interface of a rapidly evaporating liquid are found for a range of wavenumbers of the surface wave perturbation. At large evaporating mass flow rates the instability is very strong with growth times of a millisecond or less. A discussion of the physical mechanism leading to the instability is given.
Growth rates of parametric instabilities driven by two pumps
Authors: Milovich José L. , Fried Burton D. , Morales G. J.
Published: March 2003

The parametric instability growth rate of ion-acoustic and Langmuir waves, driven unstable by two uniform pumps near the Bohm–Gross frequency, is calculated as a function of pump amplitudes and frequencies. Two instability mechanisms can be identified: one corresponds to the usual, single pump parametric instabilities (decay and oscillating two stream), while the other is similar to that found in the Mathieu equation. The interaction between these two mechanisms results in a nonmonotonic dependence of the growth rate on the pump amplitudes and frequencies: both cancellation and enhancement are obtained for various values of the parameters. An analytic study of the relevant dispersion relation using Hill’s method is complemented by numerical studies in both the frequency and time domains.
Density threshold for parametric instability of lower-hybrid waves in tokamaks
Authors: Liu C. S. , Tripathi V. K. , Chan V. S. , Stefan V.
Published: March 2003

Lower-hybrid waves of finite wavenumber in a tokamak are susceptible to parametric instabilities when a certain threshold in density and power is exceeded. For typical tokamak temperatures, the channel of decay with a large growth rate is found to be due to the nonlinear ion-cyclotron damping of the beat wave generated by the pump and the lower-hybrid sideband. We furthermore compute the spectrum of the sideband at ω0−nωci through the nonlinear cascade of parametric interaction. The resonant decay into ion-cyclotron waves is also considered and shown to have a lower density threshold close to the critical density above which there is no current drive and occurs preferentially in a narrow region near the edge.
Stellarator equilibria and the problem of position control
Authors: Freidberg J. P. , Politzer P. A. , Rosenau Philip
Published: March 2003

A class of low-β stellarator magnetohydrodynamic (MHD) equilibria with β∼(a/R0)2 is introduced, and the corresponding toroidal shift is calculated. It is shown that an apparent paradox exists with regard to the problem of position control in that a vertical field is capable of shifting vacuum flux surfaces, but produces no net body force on a current-free stellarator. This paradox is resolved by an analysis of the transient response of the plasma and demonstrates how the vertical field can be used as a means of position control.
Inadequacies of finite Larmor radius treatments of the internal tilting instability in field-reversed configurations
Authors: Schwarzmeier J. L. , Seyler C. E.
Published: March 2003

A finite Larmor radius treatment of the tilting instability for field-reversed configurations is presented. It is shown on two accounts that such a treatment is inappropriate. First, the finite Larmor radius terms become infinite at the field null of the magnetic axis, because of the breakdown of the small Larmor radius assumption. Second, numerical computations using realistic parameters show that the magnetic moments of the ions are very poorly conserved at the tips of the flux surfaces in field-reversed configuration equilibria. Therefore finite Larmor radius theories cannot be used reliably to explain the observed stability to tilting of field-reversed configuration experiments.
Self-consistent, analytic, periodic-loop-antenna theory
Authors: Puri Satish
Published: March 2003

Loop-antenna coupling to toroidal plasmas is simulated in a flat geometry by an infinitely repeated array of finite loops in order to obtain a discrete spectrum along the y (azimuthal) as well as the z (toroidal) directions. The electromagnetic field of the entire configuration, including the wall, the plasma, and the Faraday shield, is analytically expressed in terms of the antenna current. The self-consistent antenna current is determined by variational techniques which also yield the antenna impedance. Finally, the theory is specifically applied to the case of ion-cyclotron-wave coupling. An approach for obtaining broadband, reflectionless coupling is introduced.
Relativistic ponderomotive Hamiltonian
Authors: Grebogi Celso , Littlejohn Robert G.
Published: March 2003

The relativistic ponderomotive Hamiltonian is derived under as general conditions as possible. Arbitrary kρ, E∥/E⊥, ω/Ω, v/c<1, wave polarization, spatial modulation of the wave, and nonuniformities in the background electric and magnetic fields are introduced in a systematic way. This calculation is a modification of guiding center theory, because in addition to averaging over gyration, there is also an averaging over rapid oscillations of the wave. Therefore, as a by-product of our objective, a new formulation of the relativistic guiding center motion is derived.
Stationary convection due to resistivity, viscosity, and thermal conductivity in a cylindrical plasma
Authors: Gomberoff L. , Palma G.
Published: March 2003

The stability of a current-carrying cylindrical plasma is studied by using the nonideal magnetohydrodynamic equations in a shearless magnetic field. It is shown that for each m mode there are four marginal stationary states which, under some conditions, give rise to large scale stationary convection when nonlinear effects are taken into account.
Quantitative explanation of oscillating two-stream and parametric decay instabilities in terms of wave pressure
Authors: Mulser P. , Giulietti A. , Vaselli M.
Published: March 2003

The exact equations of motion for the oscillating two-stream and parametric decay instabilities (OTSI and PDI) are derived in the reference system co-moving with the ion-acoustic disturbance and their physical interpretation in terms of wave pressure is presented. It is found that OTSI and PDI behave differently: whereas in the OTSI the ponderomotive force is shifted by −π/2 with respect to the disturbance, in the PDI case it is in phase with the propagating ion wave, as in stimulated Brillouin and Raman scattering. The decisive role of the pressure of an electrostatic wave is stressed.
The three-dimensional flow due to a stretching flat surface
Authors: Wang C. Y.
Published: March 2003

An exact similarity solution of the Navier–Stokes equations is found. The solution represents the three-dimensional fluid motion caused by the stretching of a flat boundary.
The effect of surface tension on the shape of the Kirchhoff jet
Authors: Vanden-Broeck Jean-Marc
Published: March 2003

The effect of surface tension on the shape of a two-dimensional jet emerging from an orifice is considered. It is shown that the slope of the surface profile of the jet is not continuous at the separation points. Both velocity and curvature are infinite at these points. The problem is solved numerically by series truncation. Jet profiles are presented for various values of the surface tension. In addition, perturbation solutions for both small and large values of the surface tension are derived.
Radial transport reduction in tandem mirrors using end-wall boundary conditions
Authors: Hooper E. B. , Baldwin D. E. , Fowler T. K. , Kane R. J. , Turner W. C.
Published: March 2003

Results from the Tandem Mirror Experiment-Upgrade (TMX-U) demonstrate that radial transport in the plasma volume can be affected by the boundary conditions at the end wall. Measurements in which end-wall plates, mapping to the plasma core, are switched from floating to grounded during plugging operation demonstrate that this floating increases the build-up rate of the central cell plasma (by increasing the radial confinement time), steepens the core density profile, and affects the plasma throughout the entire cross section.
Electron transport in the ELMO Bumpy Torus in the low collision frequency limit
Authors: Hastings D. E.
Published: March 2003

The electron neoclassical transport coefficients are calculated in a bumpy torus for the low collisionality regime. The electron radial drift is calculated as a function of the plasma position, as well as the poloidal electric field, which is determined self-consistently. A bounce-averaged differential collisional operator is used and the results are compared to previous treatments using a BGK operator.
Implications of applying a global energy balance to laser-supported and chemical detonation waves
Authors: Jumper E. J.
Published: March 2003

A closer examination of the conditions needed to propagate a steady-state shock wave is made and generalized to include energy added in the vicinity of the wave via both laser deposition and chemical reactions. This analysis yields slightly different results than standard detonation theory, and these differences are explored. A case is made for the correctness of the present method by citing the results of other researchers.
Stability boundary of the Taylor vortex flow
Authors: Park Kwangjai , Jeong Kwangho
Published: March 2003

The stability of the Taylor vortex state in a circular Couette geometry is investigated by measuring its transition to a wavy vortex state. Seven different radius ratios, ranging from 0.7767 to 0.7972, are used to map out the stability boundaries in the Reynolds number–radius ratio plane. The results verify several important features predicted by Jones.
The effusing core at the center of a vortex boundary layer
Authors: Phillips W. R. C.
Published: March 2003

The flow that results when a potential vortex rotates normal to a stationary horizontal disc is considered. This takes the form of an inward flowing boundary layer on the disc which effuses into, and ultimately forms, the core of the vortex. The pressure on the disc falls sharply toward the vortex axis and, over the boundary layer region, is essentially that of the outer flow. The radius at which the base pressure field first deviates appreciably from that of the interior is defined as r1, the radius of the effusing core. This radius and the pressure coefficient at the disc center, C0(0), are determined from radial pressure measurements on the disc over the range of Reynolds numbers, Re, from 3.0×103 to 3.0×104, where Re is based on the radius and the velocity at the disc edge. Three phases are observed as Re is varied. In the first the flow is laminar, r1∝Re−1/2 and C0(0)+1∝Re. The radius r1 continues to decrease and C0(0) to increase with Re in the second phase (1.0×104<Re<1.55×104), but faster than in the first, while in the third r1 grows and C0(0) falls. The behavior in the latter phases is thought to reflect a transition to turbulence, but several puzzling features are present and further experiments are necessary.
Development of a differential equation for the ambipolar electric field in a bumpy torus in the low collision frequency limit
Authors: Hastings D. E.
Published: March 2003

In a bumpy torus the radial electric field is determined by the constraint of ambipolarity. If both species are dominated by nonresonant diffusion, then the ambipolarity relationship as it is usually formulated is algebraic in the electric field. The solutions of this algebraic equation may have a discontinous first derivative of the electric field. The unphysical situation arises from the neglect of the finite orbit deviation from the pressure surface. If the fluxes are calculated to higher order in the inverse aspect ratio, a second-order differential equation for the electric field is obtained that will give a continuous first derivative for the electric field.
Comparative analysis of microsatellite loci in four fruit fly species of the genus Ceratitis (Diptera: Tephritidae)
Authors: Baliraine F.N. , Bonizzoni M. , Osir E.O. , Lux S.A. , Mulaa F.J. , Zheng L. , Gomulski L.M. , Gasperi G. , Malacrida A.R.
Published: March 2003

The possibility to cross-species amplify microsatellites in fruit flies of the genus Ceratitis was tested with the polymerase chain reaction (PCR) by analysing 23 Ceratitis capitata (Wiedemann) microsatellite markers on the genomic DNA of three other economically important, congeneric species: C. rosa (Karsch), C. fasciventris (Bezzi) and C. cosyra (Walker). Twenty-two primer pairs produced amplification products in at least one of the three species tested. The majority of the products were similar, if not identical in size to those expected in C. capitata. The structures of the repeat motifs and their flanking sequences were examined for a total of 79 alleles from the three species. Sequence analysis revealed the same repeat type as the homologous C. capitata microsatellites in the majority of the loci, suggesting their utility for population analysis across the species range. A total of seven loci were differentially present/absent in C. capitata, C. rosa, C. fasciventris and C. cosyra, suggesting that it may be possible to differentiate these four species using a simple sequence repeat-based PCR assay. It is proposed that medfly-based microsatellite markers could be utilized in the identification and tracing of the geographical origins of colonist pest populations of the four tested species and in the assessment of their risk and invasive potentials; thereby assisting regulatory authorities in implementing quarantine restrictions and other pest control measures.
Scenario Analysis of Chinese Passenger Vehicle Growth
Authors: Kobos Peter H. , Erickson Jon D. , Drennen Thomas E.
Published: March 2003

This article reports on a simulation and scenario analysis of Chinese passenger vehicle growth and resulting energy demand and CO2emissions. The model includes provincial level logistic growth functions with saturation levels representative of neighboring Asian economies, income growth measured in international dollars, and both estimated and literature‐based income elasticities. Scenarios explore variation in key parameters, including income and population growth rates, elasticity income ranges, fuel economy, and vehicle saturation. Countrywide base case results estimate growth from 4.22 to 54.33 passenger vehicles per thousand people from 1995 to 2025. Resulting passenger vehicle oil demands and CO2emissions increase nearly 17‐fold.
Resistance to change: a literature review and empirical study
Authors: Pardo del Val Manuela , Martínez Fuentes Clara
Published: March 2003

This paper examines organizational change, focusing on the distinction of changes according to their scope and presenting a typology of evolutionary and strategic changes. It also offers an in‐depth study of resistance to change. Through empirical research, the paper analyzes the importance of the sources of resistance to change defined theoretically, and considers both types of changes. The article shows which sources of resistance differ most, according to the scope of change, offering hints about where organizations should pay special attention when initiating a change process.
Law and the ethics of transformational leadership
Authors: Odom Lamar , Green Mark T.
Published: March 2003

Black’s Law Dictionarydefines law as a body of rules of action or conduct that govern behavior of individuals within society. A contemporary definition of ethical leadership is leadership that engages in ethical conduct that is based on right or wrong behavior towards members of society. Therefore, a common nexus between law and ethical leadership is a concern for the well‐being of members of society. The purpose of this article is to explore the relationship between law and ethical leadership. Specifically, through analysis of several legal cases, the author seeks to illustrate how applying principles of transformational leadership: idealized influence, intellectual stimulation, inspirational motivation and individualized consideration, to the ethical dilemmas faced by managers in the respective cases, would have diminished the need for involvement by the courts. Consequently, this article concludes that applying principles of transformational leadership will more likely than not lead to less litigation and better ethical outcomes than the more common transactional leadership style.
Rheological studies of shellac
Authors: Goswami D.N. , Jha P.C. , Mahato K.
Published: March 2003

The melt‐viscosity of shellac at various temperatures, the solution viscosity of shellac and the solution viscosity of several shellac‐based varnishes were investigated using a cone and plate rheometer. The study revealed information regarding yield stress (minimum force required for initiating flow) and thixotropic properties of shellac and shellac‐based materials. Such information will be useful for developing shellac‐based moulded articles and shellac‐based varnish compositions.
Electronic tools for cataloging
Authors: Khurshid Zahiruddin
Published: March 2003

BiblioFile marked the beginning of the availability of cataloging tools in electronic format based on microcomputer technology. During the last 17 years, some of these tools have evolved from CD‐ROM‐based to Web‐based versions. The ease of use, updated files, and lower cost of electronic tools have made them all the more popular among catalogers. This paper reviews electronic versions of various cataloging tools and discusses their salient features.
On-Line Chatter Detection Using Wavelet-Based Parameter Estimation
Authors: Choi Taejun , Shin Yung C.
Published: March 2003

A new method for on-line chatter detection is presented. The proposed method characterizes the significant transition from high dimensional to low dimensional dynamics in the cutting process at the onset of chatter. Based on the observation that cutting signals contain fractal patterns, a wavelet-based maximum likelihood (ML) estimation algorithm is applied to on-line chatter detection. The presented chatter detection index γ is independent of the cutting conditions and gives excellent detection accuracy and permissible computational efficiency, which makes it suitable for on-line implementation. The validity of the proposed method is demonstrated through the tests with extensive actual data obtained from turning and milling processes.
A Method for Sensor Selection in Reconfigurable Process Monitoring
Authors: Wang Litao , Kannatey-Asibu, Elijah , Mehrabi Mostafa G.
Published: March 2003

Sensor selection is important for process monitoring. Each time a machining system is reconfigured, the corresponding monitoring system needs to be re-designed for effective detection of the faults of interest. To accomplish this, a sensor selection methodology is proposed in this paper. Fuzzy theory is utilized for the multi-criteria decision-making process. Evaluation criteria are selected based on a thorough study of fault characteristics. Under subjective criteria, the ratings of different sensors are evaluated using linguistic terms, which are converted to trapezoidal fuzzy numbers. Under objective criteria, the fuzzy performance of each sensor is obtained directly from its specifications. The suitable sensor or sensors can be selected by aggregating and ranking the fuzzy numbers. Sensor selection in the turning process is used to illustrate the proposed methodology.
Reflection and Transmission of Ship Waves by Floating Barriers
Authors: Miao Quan-Ming , Chwang Allen T.
Published: March 2003

The reflection and transmission of ship waves by vertical floating barriers located on both sides of a fairway are investigated by the modified Dawson’s method in this paper. The free surface is specially treated to take into account the floating barriers. The wave pattern and the wave energy density between and outside the barriers are obtained. It is found that the reflection and transmission performance of a barrier is associated with its width and height. For a wider or higher barrier, more ship waves are reflected by it. A vertical floating barrier with a reasonable width and height can reduce ship waves in the outer region very efficiently.
Constitutive Expression of a Bacterial Pattern Recognition Receptor, CD14, in Human Salivary Glands and Secretion as a Soluble Form in Saliva
Authors: Uehara Akiko , Sugawara Shunji , Watanabe Kouichi , Echigo Seishi , Sato Mitsunobu , Yamaguchi Takahiro , Takada Haruhiko
Published: March 2003

Saliva contains a number of proteins and glycoproteins that protect oral tissues, but little is known about the role of human saliva in innate immunity. Here we showed that human major salivary gland cells constitutively expressed a bacterial pattern recognition receptor, CD14, by immunohistochemistry. Human salivary gland cells in culture express CD14 mRNA and a 55-kDa CD14 protein in, but not on the cells, and secrete a soluble form with the same molecular mass. Human whole saliva contains a 55-kDa CD14, and the concentration of parotid saliva was 10-fold higher than whole saliva, which is comparable to that of serum CD14. Levels of CD14 in unstimulated whole and parotid saliva were unchanged before and after a meal and between unstimulated and stimulated saliva, indicating that saliva CD14 is constitutively secreted into the oral cavity. In contrast, lipopolysaccharide (LPS)-binding protein was below the detectable level. The saliva CD14 is functionally active in that it mediated the activation of CD14-lacking intestinal epithelial cells by LPS in a Toll-like receptor 4-dependent manner. These results suggested that saliva CD14 is important for the maintenance of oral health and possibly intestinal homeostasis.
Elevated Levels of Matrix Metalloproteinase 9 and Tissue Inhibitor of Metalloproteinase 1 during the Acute Phase of Kawasaki Disease
Authors: Chua Pong Kian , Melish Marian E. , Yu Qigui , Yanagihara Richard , Yamamoto Kara S. , Nerurkar Vivek R.
Published: March 2003

Kawasaki disease (KD) is an acute, self-limiting, multisystem vasculitis of unknown etiology affecting infants and young children. Unless treated promptly with high-dose intravenous gamma globulin and aspirin, patients frequently develop coronary aneurysms. Previously, matrix metalloproteinase 9 (MMP-9), which is secreted complexed to tissue inhibitor of metalloproteinase 1 (TIMP-1), has been implicated in abdominal aortic aneurysm formation. Since the clinical and pathological features of KD include inflammation and weakening of blood vessels, we analyzed acute- and convalescent-phase paired plasma or serum samples from 31 KD patients, 7 patients who did not completely meet the criteria for KD, and 26 non-KD controls (9 febrile and 17 afebrile patients) for pro-MMP-9 (92 kDa) enzyme activity by gelatin zymography and for active MMP-9 (83 kDa), pro-MMP-9, and TIMP-1 protein levels by enzyme-linked immunosorbent assay. Statistical analysis was performed by using Studentttests, linear regression, and the Wilcoxon rank-sum test. Markedly elevated pro-MMP-9 enzymatic activity, pro-MMP-9 protein levels, and TIMP-1 protein levels were found during the acute phase of illness in patients with clinically established KD and in patients who were suspected of having KD but did not meet all of the criteria. There was no significant difference in active MMP-9 levels. Furthermore, pro-MMP-9 and TIMP-1 protein levels were significantly elevated among KD patients, compared to those of febrile and afebrile non-KD controls. The significantly elevated pro-MMP-9 enzyme and protein levels during the acute phase of KD may reflect vascular remodeling or an inflammatory response to a microbial agent, suggesting a pathophysiological role for MMP-9 in coronary aneurysm formation.
Interleukin 12 in Part Regulates Gamma Interferon Release in Human Whole Blood Stimulated withLeptospira interrogans
Authors: de Fost Maaike , Hartskeerl Rudy A. , Groenendijk Martijn R. , van der Poll Tom
Published: March 2003

Heat-killed pathogenicLeptospira interrogansserovar rachmati induced the production of gamma interferon (IFN-γ) and the IFN-γ-inducing cytokines interleukin-12p40 (IL-12p40) and tumor necrosis factor alpha in human whole blood in vitro. The production of IFN-γ was largely dependent on IL-12. These data establish that pathogenic leptospires can stimulate the production of type I cytokines involved in cellular immunity.
Leucine Biosynthesis in Fungi: Entering Metabolism through the Back Door
Authors: Kohlhaw Gunter B.
Published: March 2003

After exploring evolutionary aspects of branched-chain amino acid biosynthesis, the review focuses on the extended leucine biosynthetic pathway as it operates in Saccharomyces cerevisiae. First, the genes and enzymes specific for the leucine pathway are considered: LEU4 and LEU9 (encoding the α-isopropylmalate synthase isoenzymes), LEU1 (isopropylmalate isomerase), and LEU2 (β-isopropylmalate dehydrogenase). Emphasis is given to the unusual distribution of the branched-chain amino acid pathway enzymes between mitochondrial matrix and cytosol, on the newly defined role of Leu5p, and on regulatory mechanisms governing gene expression and enzyme activity, including new evidence for the metabolic importance of the regulation of α-isopropylmalate synthase by coenzyme A. Next, structure-function relationships of the transcriptional regulator Leu3p are addressed, defining its dual role as activator and repressor and discussing evidence in support of the self-masking model. Recent data pointing at a more extended Leu3p regulon are discussed. An overview of the layered controls of the extended leucine pathway is provided that includes a description of the newly recognized roles of Ilv5p and Bat1p in maintaining mitochondrial integrity. Finally, branched-chain amino acid biosynthesis and its regulation in other fungi are summarized, the question of leucine as metabolic signal is addressed, and possible directions of future research in this area are outlined.
Evaluation of Antinociceptive, Anti-inflammatory and Antipyretic Effects of Strobilanthes cusia Leaf Extract in Male Mice and Rats
Authors: Ho Yu-Ling , Kao Kuo-Ching , Tsai Huei-Yann , Chueh Fu-Yu , Chang Yuan-Shiun
Published: March 2003

The leaf of Strobilanthes cusia (Acanthaceae), popularly known as Da-Ching-Yeh, has been commonly used in traditional Chinese medicine. It is used for influenza, epidemic cerebrospinal meningitis, encephalitis B, viral pneumonia and mumps. It is also used to treat sore throat, aphthae and inflammatory diseases with redness of skin, etc. In this study, we evaluated the antinociceptive, anti-inflammatory and antipyretic effects of methanol extract of Strobilanthes cusia leaf. The results showed that the extract significantly inhibited the writhing responses of mice and decreased the licking time on both the early and late phases of the formalin test in a dose-dependent manner. It also reduced the paw edema induced by carrageenan in rats. In addition, it potently attenuated pyrexia induced by lipopolysaccharide.
Analgesic Effects of Different Acupoint Stimulation Frequencies in Humans
Authors: Attele Anoja S. , Mehendale Sangeeta , Guan Xiongfei , Dey Lucy , Yuan Chun-Su
Published: March 2003

Transcutaneous electrical acupoint stimulation (TEAS) provides a convenient and standardized technique for pain treatment. The cold-pressor test is a simple and reliable model in humans for the induction of tonic pain. In this controlled study, the effects of TEAS on cold pressor-induced pain were evaluated in 22 healthy human subjects. Electrical stimulation at 4 Hz and 32 Hz was applied to He-Gu (LI 4) and Nui-Guan (P 6) acupoints for 15 minutes. Pain score ratings were evaluated at four time points from 30–170 seconds during the cold-pressor test. We observed an analgesic effect at both 4 Hz and 32 Hz of stimulation, and pain score rating reductions were statistically significant compared to control (p < 0.01). Our data support the efficacy of TEAS analgesia. However, there was no significant difference between pain scores at 4 Hz and 32 Hz stimulation.
Choto-san Prevents Occurrence of Stroke and Prolongs Life Span in Stroke-Prone Spontaneously Hypertensive Rats
Authors: Shimada Yutaka , Yang Qiao , Yokoyama Koichi , Goto Hirozo , Kasahara Yuji , Sekiya Nobuyasu , Hikiami Hiroaki , Terasawa Katsutoshi
Published: March 2003

The effects of long-term oral administration of Choto-san (Diao-Teng-San in Chinese) extract on the occurrence of stroke and life span were investigated in stroke-prone spontaneously hypertensive rats (SHR-SPs). Twenty-four rats were ramdomized into three groups. From 8 weeks of age, 0.1% and 0.3% Choto-san groups were given water containing 0.1% (150 mg/kg/day) and 0.3% (450 mg/kg/day) Choto-san extract, respectively. A control group was given only water. The mean survival times of the control group, 0.1% and 0.3% Choto-san groups were 122.1, 159.8 and 176.8 days, respectively. The percent survivals of both the 0.1% and 0.3% Choto-san groups were significantly enhanced compared to the control (Kaplan-Meier analysis followed by log-rank test; 0.1% Choto-san: p < 0.05; 0.3% Choto-san: p < 0.05). Furthermore, the cumulative percent occurrence of neurological and behavioral signs accompanying stroke in the 0.3% Choto-san group was significantly inhibited compared to the control (p < 0.05). These results suggested that Choto-san prevents the occurrence of stroke and prolongs the life span of SHR-SPs.
FILAMENTATION AND SUPERCONTINUUM GENERATION DURING THE PROPAGATION OF POWERFUL ULTRASHORT LASER PULSES IN OPTICAL MEDIA (WHITE LIGHT LASER)
Authors: CHIN S. L. , BRODEUR A. , PETIT S. , KOSAREVA O. G. , KANDIDOV V. P.
Published: March 2003

The fundamental physical mechanism responsible for the self-focussing, filamentation, supercontinuum generation and conical emission of a powerful ultrashort laser pulse in a transparent optical medium is reviewed. The propagation can be described by the model of moving focus modified by the defocussing effect of the self-induced plasma through multiphoton interaction with the medium. Spatial and temporal self-phase modulation in both the neutral Kerr medium and the plasma transform the pulse into a chirped (elongated) and strongly deformed pulse both temporally and spatially. The manifestation of the deformation is supercontinuum generation and conical emission. A new phenomenon of refocussing was observed. It is due to the diffraction of the trailing part of the pulse by the plasma that results in a ring structure of positive index changes surrounding the plasma column. This ring structure refocuses the pulse partially. The measured coherence lengths of the various frequencies components of the supercontinuum are independent of the optical media used and are essentially equal to that of the pump laser pulse when compared to an incoherent white light source. We thus justify that such a deformed pulse with a very broad spectrum could be called a chirped white light laser pulse.
APPLICATION OF PHOTOREFRACTIVE FIBER AND WAVEGUIDE GRATINGS TO FAST SPEED NARROW BAND TUNABLE FILTERS
Authors: YIN SHIZHUO
Published: March 2003

In this paper, the progress of the application of photorefractive fiber and waveguide crystal gratings to a narrow band, fast speed, tunable filter is presented. This novel filter is based on tunable Bragg grating. It uses the diffraction effect of Bragg grating to select the wavelength and the electro-optic effect of the grating to tune the effective grating period. Several approaches of fabricating this type of tunable Bragg grating based filter are discussed and some preliminary results are provided. It is shown that the tuning speed of this type of filter can be in the ns range and the bandwidth can be as narrow as 0.01 nm.
HIGH- AND LOW-MOLAR-MASS LIQUID CRYSTAL MIXTURES FOR PHOTOREFRACTIVE APPLICATIONS
Authors: ONO HIROSHI , KAWATSUKI NOBUHIRO
Published: March 2003

We describe a highly efficient photorefractive material possessing high-molar-mass liquid crystal (H-LC), low-molar-mass liquid crystal (L-LC), and photoconductive agent. These photorefractive high- and low-molar-mass liquid crystal mixtures (HL-LCMs) show high-performance in a thick grating regime (Bragg regime) under low dc electric fields (< 1 V/μm). The photorefractive properties are strongly dependent on the concentration of the H-LC. The fastest response time of 70 ms is achieved with a gain coefficient of 213 cm-1 in the case of 10 wt% of the H-LC with 0.18 V/μm. The largest gain coefficient of over 600 cm-1 is achieved with the response time of 2.6 s in the case of 40 wt% of the H-LC with 0.7 V/μm. In addition, our future directions in this research area are also presented.
OPTICAL REORIENTATION IN DYE-DOPED LIQUID CRYSTALS
Authors: JÁNOSSY ISTVÁN
Published: March 2003

The light-induced reorientation of nematic liquid crystals is discussed with special emphasis on the effect of dye-dopants. A molecular model is presented which accounts for the large increase of the optical torque, observed in absorbing nematics. An analogous process is described for dye-doped isotropic liquids and the role of photoisomerization is considered as well.