bluuebunny/crossref_metadata_2025 huggingface dataset:
Using courseware to deliver library instruction via the Web: four examples
Authors: Getty Nancy K. , Burd Barbara , Burns Sarah K. , Piele Linda
Published: July 2002

Librarians at four academic institutions present their experiences using four courseware products (Web Course in a Box, Blackboard, eCollege.com, and WebCT) to teach information literacy skills. Objectives, methods, content, and student populations vary from place to place. In all four cases, with some reservations, librarians deem courseware a valuable tool for delivery of library instruction. They agree on the following primary advantages: support for interactivity; support for assessment/grade management; support for distance education; relatively quick development time; relatively low technical skill requirement; and raise the following concerns: inability to integrate quiz questions into the text of lessons; and diminution of interpersonal contact.
LANSLIDE
Authors: Harrison Ken
Published: July 2002

Lancaster University Library developed an in‐house software package,
LANSLIDE, for its slide collection in 1987. Examines the system, which
includes slide cataloguing, mini‐label production, keyword searching,
and classmark searching. A recent development has been the introduction
of an issue module. The system has resulted in savings in staff time,
and much improved access to the slide collection.
From research to implementation: finding leverage for prevention
Authors: Rayner Charlotte
Published: July 2002

This paper relates research on workplace bullying to the prevention measures which an organisation might consider implementing. The implications of collecting research information only from targets of bullying is highlighted, and discussed in relation to identifying bullies and targets. Incidence studies are used to track environmental patterns and processes. Included in such studies is the recent UK UNISON survey, where patterns of consistency are found between targets and non‐targets in attitude questions regarding the causes of bullying, but strong divergence of response regarding other parameters. The effectiveness of actions taken by targets of bullying is also reported. These find that reports of bullying stopping as a result of action by targets are rather rare, and advising targets to discuss the situation with the bully without professional support (such as from a personnel officer or union representative) is probably misguided as retaliation from the bully is likely.
An algebraic multigrid solver for finite element computations in solid mechanics
Authors: Boersma A. , Wriggers P.
Published: July 2002

Presents an implementation of the algebraic multigrid method. It can work in two ways: as pure multigrid method and as a pre‐conditioner for the conjugate gradient method. Shows applications of the iterative solvers for problems in linear and non‐linear elasticity. Shows the range of possible applications with different examples with regular and non‐regular meshes and three‐dimensional problems.
Benchmark problems for optimal shape design for 2D eddy currents
Authors: Starzynski Jacek , Wincenciak Stanislaw
Published: July 2002

Two new benchmark inverse problems for eddy currents are proposed. The first originates in the optimal design of the tubular inductive heater. The authors’ goal is to offer a simple problem which will check whether new software is able to minimize a multimodal objective function. The second benchmark is a simplified model of a hardening device. The purpose of this problem is to test the ability of the software to deal with different design parameters. This benchmark can be easily extended for more complicated, coupled fields problems. For both benchmarks reference standard solutions are presented. They were obtained using a finite element package for electromagnetics, developed by the authors.
Factors Contributing to Commitment to the Teaching Profession
Authors: Mohan Raju P. , Srivastava R.C.
Published: July 2002

Presents a need to look at commitment of teachers to their profession in
terms of effect, goals and values of the profession. Measuring
commitment on this basis, explores the contributing factors and
variables to commitment. Empirical evidence on 454 senior secondary
school teachers of Delhi, with the help of discriminant analysis,
revealed that perceived characteristics of profession, workrelated
personality and desire to improve one′s own skills were contributing in
that order. The constituent variables that discriminated more and less
committed teachers were perceived status, expectations of significant
persons, interest in profession, intrinsic motivation, social support,
positive group attitudes, perceived advancement and desire to improve
skills for professional purpose.
Occupational stress of teachers: biographical differences in a large school system
Authors: McCormick John
Published: July 2002

Presents the results of an analysis of questionnaire and interview data revealing significant differences in occupational stress between groups of public school teachers, in New South Wales, Australia. In particular, emphasizes the importance of differentiating between executive and classroom teachers, primary/infants and secondary teachers, teachers at different career stages and teachers in geographical locations, when planning to alleviate stress in the future. The fact that primary/infants teachers reported greater stress attributable to student misbehaviour than secondary teachers reinforces the need to distinguish between the perceived “objective strength” of a stressor and the degree of distress felt by a teacher.
Effects of heat generation/absorption and thermophoresis on hydromagnetic flow with heat and mass transfer over a flat surface
Authors: Chamkha Ali J. , Issa Camille
Published: July 2002

The problem of steady, two‐dimensional, laminar, hydromagnetic flow with heat and mass transfer over a semi‐infinite, permeable flat surface in the presence of such effects as thermophoresis and heat generation or absorption is considered. A similarity transformation is used to reduce the governing partial differential equations into ordinary ones. The obtained self‐similar equations are then solved numerically by an implicit, tri‐diagonal, finite‐difference scheme. Favourable comparison with previously published work is performed. Numerical results for the velocity, temperature and concentration profiles as well as for the skin‐friction coefficient, wall heat transfer and particle deposition rate are obtained and reported graphically for various parametric conditions to show interesting aspects of the solution.
Semantic processing performance of Internet machine translation systems
Authors: Watters Paul A. , Patel Malti
Published: July 2002

The Internet has the potential to facilitate understanding across cultures and languages by removing the physical barriers to intercultural communication. One possible contributor to this development has been the recent release of freely‐available automated direct machine translation systems, such as AltaVista with SYSTRAN, which translates from English to five other European languages (French, German, Italian, Spanish and Portuguese), and vice versa. However, concerns have recently been raised over the performance of these systems, and the potential for confusion that can be created when the intended meaning of sentences is not correctly translated (i.e. semantic processing errors). In this paper, we use an iterative paradigm to examine errors associated with interlingual divergence in meaning arising from the automated machine translation of English proverbs. The need for the development of Web‐based translation systems, which have an explicit cross‐linguistic representation of meaning for successful intercultural communication, is discussed.
Wealth Effects of International Acquisitions by US Banks
Authors: Gleason Kimberly C. , Mathur Ike
Published: July 2002

The wealth effects of international acquisitions by US banks (USBs) are examined in this study. The results show that shareholders of USBs experience significant negative excess returns when banks make international acquisition announcements. Excess returns are significantly negative when banks announce acquisitions in developed countries. The excess returns are not different for first time versus subsequent acquisition announcements. However, excess returns are significantly negative for USBs that are frequent acquirers overseas. Sampling by time periods, negative excess returns are observed during the fixed exchange rate regime (1965–1973) and during the post Tax Reform Act of 1986 era. Cross‐sectional regressions indicate that profitability and efficiency measures are positively associated with excess returns.
Stress preconditioning attenuates oxidative injury to the alveolar epithelium of the lung following haemorrhage in rats
Authors: Pittet J. F. , Lu L. N. , Geiser T. , Lee H. , Matthay M. A. , Welch W. J.
Published: July 2002

Inhibition of cAMP‐dependent stimulation of vectorial fluid transport across the alveolar epithelium following haemorrhagic shock is mediated by reactive nitrogen species released within the airspaces of the lung. We tested here the hypothesis that the prior activation of the cellular heat shock or stress response, via exposure to either heat or geldanamycin, would attenuate the release of airspace nitric oxide (NO) responsible for the shock‐mediated failure of the alveolar epithelium to respond to catecholamines in rats. Rats were haemorrhaged to a mean arterial pressure of 30–35 mmHg for 60 min, and then resuscitated with a 4 % albumin solution. Alveolar fluid clearance was measured by change in concentration of a protein solution instilled into the airspaces 5 h after the onset of haemorrhage. Stress preconditioning restored the cAMP‐mediated upregulation of alveolar liquid clearance after haemorrhage. The protective effect of stress preconditioning was mediated in part by a decrease in the expression of iNOS in the lung. Specifically, stress preconditioning decreased the production of nitrite by endotoxin‐stimulated alveolar macrophages removed from haemorrhaged rats or by A549 and rat alveolar epithelial type II cell monolayers stimulated with cytomix (a mixture of TNF‐α, IL‐1β and IFN‐γ) for 24 h. In summary, these results provide the first in vivo evidence that stress preconditioning restores a normal fluid transport capacity of the alveolar epithelium in the early phase following haemorrhagic shock by attenuating NO‐mediated oxidative stress to the lung epithelium.
Formulation and Analysis of EHL Problems for Soft Materials
Authors: Kudish Ilya I.
Published: July 2002

This paper presents a qualitative and numerical analysis of the new formulation of a steady problem for lubricated rollers made of elastic materials with low Young’s modulus. The feature that makes this formulation different from the classic one is that the linear velocities of the surfaces take into account tangential deformations of elastic materials. Therefore, in Reynolds equation, the surface linear velocities are represented by functions of the location in the contact region instead of constants. The new formulation predicts the formation of a significant depression (dimple) in the contact surfaces of soft materials as opposed to flat surfaces in the classic EHL theory. The paper also describes the dependence of dimple sizes on problem parameters. [S0742-4787(00)02003-8]
A Hydraulically-Actuated Reconfigurable Tool for Flexible Fabrication: Implementation and Control
Authors: Walczyk Daniel F. , Im Yong-Tai
Published: July 2002

An automatically reconfigurable discrete tool (matrix of pins) has been developed and demonstrated for sheet metal part forming and composite part molding in the aerospace industry. A GUI-based control system positions each of the hydraulically-actuated pins according to a computer model of the intended tool surface. Open-loop position control of individual pins (timing the upward movement of each pin) is possible but accuracy and repeatability are inadequate for most sheet metal forming and composite molding applications. However, closed-loop position control is shown to provide sufficient accuracy and repeatability for these same applications. Once the pin matrix shape is set, it can be made into a rigid forming or molding tool by side clamping with a hydraulic ram. Since the pin ends are spherical in shape, the resulting dimpled tool surface is covered with an interpolating layer of material. The pins can be reset to their lowest position by either withdrawing hydraulic fluid or pushing them down with the setting platen. [S1087-1357(00)01403-9]
Simulation of Multipass Welding With Simultaneous Computation of Material Properties
Authors: Bo¨rjesson Lars , Lindgren Lars-Erik
Published: July 2002

Multipass butt welding of two 0.2 m thick steel plates has been investigated. The objective is to calculate residual stresses and compare them with measured residual stresses. The material properties depend on temperature and temperature history. This dependency is accounted for by computing the microstructure evolution and using this information for computing material properties. This is done by assigning temperature dependent material properties to each phase and applying mixture rules to predict macro material properties. Two different materials have been used for the microstructure calculation, one for the base material and one for the filler material.
Bond-Induced Longitudinal Fracture in Reinforced Concrete
Authors: Ghandehari M. , Krishnaswamy S. , Shah S.
Published: July 2002

Splitting of concrete caused by pullout of deformed rebars is investigated. The influence of specimen cross section size and geometry on the relationship between the components of stress and relative displacement at the interface is evaluated. Phase measurement interferometry is used for accurate mapping of the splitting cracks. The measured crack profiles, material model, and a fracture criterion are used in a hybrid experimental/numerical approach to evaluate the unknown normal component of traction at the interface. [S0021-8936(00)03603-5]
Sliding-Mode Adaptive Observer Approach to Chaotic Synchronization
Authors: Azemi Asad , Yaz Edwin Engin
Published: July 2002

Extensions of sliding-mode adaptive observer are presented for state reconstruction of nonlinear systems with uncertainty having unknown bounds. The observer uses nonlinear gains that are smoothened versions of classical sliding-mode gains and they are continuously updated to guarantee a globally stable observation error. This observer is applied to Chua’s circuit in a chaotic synchronization scheme. A generalization to known waveform type disturbances and measurement uncertainties is pointed out. [S0022-0434(00)02304-2]
Correspondence Principle in Viscoelastic Functionally Graded Materials
Authors: Paulino G. H. , Jin Z.-H.
Published: July 2002

This paper presents an extension of the correspondence principle (as applied to homogeneous viscoelastic solids) to nonhomogeneous viscoelastic solids under the assumption that the relaxation (or creep) moduli be separable functions in space and time. A few models for graded viscoelastic materials are presented and discussed. The revisited correspondence principle extends to specific instances of thermoviscoelasticity and fracture of functionally graded materials.
Stick-Slip, Imposition-Removal of Constraints and the Spinning Ball Problem
Authors: Djerassi S.
Published: July 2002

It has been observed that balls pressed between elastic bodies spin when subjected to linear, cyclic motion. This paper proposes an explanation to this phenomenon, based upon the stick-slip theory. To this end, a modified, vectorial formulation of the stick-slip theory is presented. The formulation is applied to a model comprising a ball pressed between pairs of springs and dampers. A computer program based on this formulation is used to predict the resulting motion. Predictions are shown to agree with experimental results. [S0021-8936(01)00701-2]
Influence of Circuitry Arrangement on the Pressure Drops of Two-Row Finned Tube Evaporators
Authors: Wang Chi-Chuan , Liu Min-Sheng , Leu Jin-Sheng
Published: July 2002

This study experimentally investigates the effect of circuitry on the refrigerant-side pressure drops of plate finned tube evaporators. Experiments were performed with countercross, parallel-cross, and z-shape arrangements. The results showed that the parallel-cross-flow circuit gives a lower pressure drop than other arrangements. Generally, the refrigerant-side pressure drops increase with air frontal velocities. However, for G=200 kg/m2s˙s and parallel flow, the pressure drops decrease with increase of air frontal velocity. This unusual characteristic is most likely related to the flow pattern transition when subjected to heat addition.
A Computational Study of a Novel Turbine Rotor Partial Shroud
Authors: Harvey Neil W. , Ramsden Ken
Published: July 2002

The over tip leakage (OTL) flow that exists between the stationary casing and the rotor tip of a shroudless HP turbine remains a major source of loss of performance for modern aero gas turbines. To date the principal approaches to reducing OTL loss have been to minimize the clearance gap and/or apply a rotating shroud to the rotor. Tip clearance control systems continue to improve, but a practical limit on tip gap remains. A rotating shroud is highly effective but increases the rotor weight, forcing it to run more slowly and thus increasing other aerodynamic losses. Additional means of reducing OTL loss are still needed. Partial shrouds (winglets) have been tried but none have entered commercial service to date. This paper presents a novel design of partial shroud derived from a review of past research. The (arbitrary) objectives were to halve the OTL loss of a shroudless rotor, at less than half the size of a full shroud. This design has been analyzed using a steady flow RANS CFD code to qualitatively determine its benefits. Attention has been paid to its validation and a realistic determination of its capabilities. The winglet is predicted to significantly improve the efficiency of a highly loaded HP turbine, by 1.2 percent–1.8 percent at 2 percent tip gap/span. A detailed understanding of the flow field shows this to be credible.
Fundamental Characteristics of a New Variable Torque Clutch With Skewed Rollers
Authors: Feng Ming , Ono Kyosuke , Mimura Kenji
Published: July 2002

In this paper, a new type of a clutch by the name of the variable torque clutch with skewed rollers is first introduced and second investigated both theoretically and experimentally. It is comprised of an inner and an outer race that are each in spatial line contact with the crossed axis cylindrical rollers. Torque transmission is delivered by a slipping induced between the rollers and the races due to skewing the rollers. The equations of the race surfaces are derived and the geometrical properties are analyzed. Based on the kinematic analysis, a roller-wedge model is proposed for this clutch in order to visualize the motion at the tangency of the rollers and the races. By assuming the linear distribution of the contact force along the spatial contact line, the transmitted torque capacity and kinematic characteristics can be evaluated properly from the solution of a set of nonlinear equilibrium equations. Several prototypes of this clutch are manufactured and measured to show the validity of this design idea and the theoretical results. The computational results are found to coincide with the experimental data. In addition, the influences of the design parameters on the fundamental characteristics are discussed in detail.
Negative Stiffness Coefficients for Magnetic Actuators Using Laplace’s Equation
Authors: Stephens L. S. , Casemore M. A.
Published: July 2002

Magnetic bearings offer high speed and low power losses as compared to film riding and rolling element bearings. Significant efforts are underway to apply magnetic bearings to gas turbines and jet aircraft engines. Negative stiffness coefficients for magnetic actuators can have a significant impact on shaft rotordynamics. These coefficients are typically computed as the sensitivity of a magnetic force expression derived from a lumped parameter reluctance network. However, as the complexity of magnetic actuator designs increases, the reluctance network method may become impractical for, or even incapable of, coefficient determination. In this paper, an alternative method is presented for determination of negative stiffness coefficients for a large class of magnetic actuators. The method solves the Dirichlet boundary value problem for the magnetomotive force in the actuator air gap, subject to periodic boundary conditions that can be represented by Fourier series. A conformal transformation to bipolar coordinates is used that results in a boundary value problem that is solvable using separation of variables. Negative stiffness coefficients are presented and the method is benchmarked against well-known solutions using the reluctance network method.
Optimal Blank Design for the Drawings of Arbitrary Shapes by the Sensitivity Method
Authors: Shim H. B. , Son K. C.
Published: July 2002

The sensitivity method is employed in this work in order to find initial blank shapes which result in desired shapes after deformation. By assuming the final deformation shape be the drawn cup with uniform trimming allowance at the flange, the corresponding initial blank which gives the desired final shape after deformation has been found. With the aid of a well-known dynamic explicit analysis code PAM-STAMP, shape sensitivity has been obtained. To get the shape sensitivity numerically, a couple of deformation processes have been analyzed. Drawings of trapezoidal cup, oil pan, and Audi front door panel, the benchmark test problem of Numisheet ’99, have been chosen as the examples. In every case the optimal blank shape has been obtained after only a few modifications without a predetermined deformation path. With the predicted optimal blank, both computer simulation and experiment are performed. Excellent agreements are obtained between simulation and experiment in every case. Through this investigation, the sensitivity method is found to be very effective in the design of arbitrary shaped drawing processes.
Hybrid Active Noise Control of a One-Dimensional Acoustic Duct
Authors: Esmailzadeh E. , Alasty A. , Ohadi A. R.
Published: July 2002

Based on the closed-form solution of a one-dimensional wave equation, the primary, secondary and acoustic feedback paths for the active control of sound in an acoustic duct have been investigated. Accurate models for the condenser microphone and loudspeaker, which include both the electro-mechanical and mechano-acoustical couplings as well as acoustical damping, have been considered. A generalized form of the filtered-x least mean square (FXLMS) algorithm that uses a more general recursive adaptive weight update equation to improve the performance of the FXLMS algorithm has been developed. Computer simulations were carried out to investigate the performance of acoustical feedback and feedback neutralization as well as the effect of boundary conditions on the performance of active noise control (ANC) systems. Comparisons of the simulation results were carried out.
Prediction of Blade-Vortex Interaction Airloads With Higher-Harmonic Pitch Controls Using the 2GCHAS Comprehensive Code
Authors: Lim Joon W. , Tung Chee , Yu Yung H.
Published: July 2002

Analytically predicted results of blade-vortex interaction (BVI) airloads, using the second- generation comprehensive helicopter analysis system (2GCHAS), are presented with the experimental results obtained from the higher-harmonic-control aeroacoustic rotor test (HART) program using a 40-percent, Mach-scaled model of the hingeless BO-105 main rotor. Correlations include airloads, blade tip deflections, and tip vortex geometry. The effects on blade airload predictions are studied with higher-harmonic pitch controls (HHC). It was concluded that the blade torsional deflection and the wake system play a very important role in predicting BVI airloads.
Moving boundaries in micro-scale biofluid dynamics
Authors: Shyy and W , Francois M , Udaykumar HS , N’dri and N , Tran-Son-Tay R
Published: July 2002

Many critical issues in biofluid dynamics occur at the boundaries between fluids, solids, or both. These issues can be very complex since in many cases the boundaries are deformable and moving. Furthermore, different characteristic times, lengths, and material properties are often present which make any computational task taxing. The present review focuses on computational modeling techniques for moving boundaries and multi-component systems with emphasis on micro-scale biofluid physics, including i) the dynamics of leukocyte (white blood cell) deformation, recovery, and adhesion; and ii) the thin-film dynamics involving tear–structure interaction in soft contact lens applications. In these problems, multiple length scales exist, and at least one of them is on the order of 10 μm or smaller. After presenting appropriate computational techniques for moving boundaries, recent research on leukocyte deformation, recovery, and adhesion is reviewed in the context of multi-component, multi-time-scale, and micro-macro interactions. The soft contact lens problem is discussed from the viewpoint of large disparities in length scales due to high aspect ratios. Depending on the nature of the problem and the goal of the computation, alternative computational techniques can successfully address the physical and numerical challenges. A major interest of this article is to stress how moving boundary techniques can be applied to provide new insights into the physico-chemical behavior of complex biological systems. To treat different time and length scales with due care in a moving boundary framework is a grand challenge in developing first-principle-based computational capabilities. There are 175 references in this review article.
Effect of Strain Gradients and Heterogeneity on Flow Strength of
Particle Reinforced Metal-Matrix Composites
Authors: Duan D-M. , Wu N. Q. , Zhao M. , Slaughter W. S. , Mao Scott X.
Published: July 2002

This paper deals with an analysis of the size effect on the flow strength of metal-matrix composites due to the presence of geometrically necessary dislocations. The work is based upon a cell model of uniaxial deformation. The deformation field is analyzed based on a requirement of the deformation compatibility along the interface between the particle and the matrix, which in turn is completed through introducing an array of geometrically necessary dislocations. The results of modelling show that the overall stress-strain relationship is dependent not only on the particle volume fraction but also on the particle size. It has been found that the material length scale in the strain gradient plasticity is dependent on the particle volume fraction, or in other words, on the relative ratio of the particle spacing to the particle size. The strain gradient is, besides the macro-strain and the particle volume fraction, inversely proportional to the particle size.
Influence of Injection Type and Feed Arrangement on Flow and Heat Transfer in an Injection Slot
Authors: Cho Hyung Hee , Ham Jin Ki
Published: July 2002

An experimental investigation is conducted to improve a slot film cooling system used for the cooling of a gas turbine combustor liner. The tangential slots are constructed of discrete holes with different injection types which are the parallel, vertical, and combined to the slot lip. The investigation is focused on the coolant supply systems of normal, inline, and counter-flow paths to the mainstream flow direction. A naphthalene sublimation technique has been employed to measure the local heat/mass transfer coefficients in a slot wall with various injection types and coolant feeding directions. A numerical simulation is also conducted to help understand the flow patterns inside the slot for different injection types. The velocity distributions at the exit of slot lip for the parallel and vertical injection types are fairly uniform with mild periodical patterns with respect to the injection hole positions. However, the combined injection type increases the nonuniformity of flow distribution with the period equaling twice that of hole-to-hole pitch due to splitting and merging of the ejected flows. The dimensionless temperature distributions at the slot exits differ little with blowing rates, injection types, and secondary flow conditions. In the results of heat/mass transfer measurements, the best cooling performance inside the slot is obtained with the vertical injection type among the three different injection types due to the effects of jet impingement. The lateral distributions of heat/mass transfer coefficients with the inline and counter-flow paths are more uniform than the normal-flow path. The average heat/mass transfer coefficients with the injection holes are about two to five times higher than that of a smooth two-dimensional slot path.
Transient Heat Conduction in a Heat Generating Layer Between Two Semi-Infinite Media
Authors: van der Tempel Leendert
Published: July 2002

The problem of transient heat conduction in a heat generating layer between two semi-infinite media has been solved. The one-dimensional thermal model is Laplace transformed. Three analytical temperature solutions are derived: two approximation solutions and an exact series solution. They are compared with respect to accuracy, convergence and computational efficiency. The approximations are computationally more efficient, and the series converge to the exact solution. The presented accurate solutions enable quick thermal analysis in terms of just 2 parameter groups, but overestimate the temperature during initialization of rewritable optical disks due to lateral heat conduction.
Bubble Characteristics in a Developing Vertical Gas–Liquid Upflow Using a Conductivity Probe
Authors: Zhang Junping , Epstein Norman , Grace John R. , Lim Kokseng
Published: July 2002

Experiments were carried out in an 82.6-mm-dia column with a perforated distributor plate. Conductivity probes on the axis of the column were used to measure local bubble properties in the developing flow region for superficial air velocities from 0.0018 to 6.8 m/s and superficial water velocities from 0 to 0.4 m/s, corresponding to the discrete bubble, dispersed bubble, coalesced bubble, slug, churn, bridging, and annular flow regimes. Bubble frequency increased linearly with gas velocity in the discrete and dispersed bubble regimes. Bubble frequency also increased with gas velocity in the slug flow regime, but decreased in the churn and bridging regimes. Bubble chord length and its distribution were smaller and narrower in the dispersed than in the discrete bubble regime. Both the average and standard deviation of the bubble chord length increased with gas velocity in the discrete, dispersed, and churn flow regimes. However, the average bubble chord length did not change significantly in the slug flow regime due to the high population of small bubbles in the liquid plugs separating Taylor bubbles. The bubble travel length, defined as the product of local gas holdup and local bubble velocity divided by local bubble/void frequency, is used to correlate bubble characteristics and to characterize the flow regimes. [S0098-2202(00)00101-2]
Moving and Rotating Sphere in the Thermal Entrance Region of a Heated Pipe
Authors: Shahcheraghi N. , Dwyer H. A.
Published: July 2002

Flow and unsteady heat transfer around a moving and rotating sphere is considered as it passes through the thermal entrance region of a heated pipe. The flow is incompressible and viscous with constant properties, and the heated pipe wall is kept at a constant temperature. Two Peclet numbers of 25 and 100 are considered along with two sphere-to-pipe-diameter ratios of 0.2 and 0.4. The flow is made three dimensional by an eccentric positioning of the sphere inside the pipe. The governing equations are solved by a validated numerical method which uses a finite volume formulation in a generalized body-fitted coordinate system. An overset (Chimera) grid scheme is used to resolve the two geometries of the pipe and sphere. The results are presented in terms of the steady pressure and viscous lift and drag forces on the sphere. In addition the unsteady heat transfer characteristics of the flow are presented in terms of the local and overall Nusselt number evolution around the sphere as it passes through the thermal entrance region of the pipe. Sphere heat-up is also given as the lumped mass sphere temperature as a function of distance from the thermal entrance. [S0022-1481(00)02402-6]
Wrap-around B-spline Surface Fitting to Digitized Data With Applications to Reverse Engineering
Authors: Weir D. J. , Milroy M. J. , Bradley C. , Vickers G. W.
Published: July 2002

The design of products containing sculptured surfaces typically begins with the crafting of a clay or wood model. The physical model must be reverse engineered to create a CAD representation. Three dimensional computer vision systems are currently being employed to digitize models in the first step of reverse engineering. In this paper, a three dimensional vision system that permits multiple viewpoint digitization is described. Furthermore, a new approach to modeling the data sets generated employing wrap-around B-spline surface patches is presented. The laser digitization and software modeling of bicycle seat and telephone handset models are presented.[S1087-1357(00)70102-X]
Prediction of Transitional Heat Transfer Characteristics of Wake-Affected Boundary Layers
Authors: Kim K. , Crawford M. E.
Published: July 2002

The presence of wake-passing in the gas turbine environment significantly modifies the heat transfer characteristics on the downstream blade surface by causing wake-induced transition. In this study, time-dependent boundary layer calculations were carried out using a model for wake-induced transition based on a prescribed time-dependent intermittent function. The model is determined from the well-known turbulent spot propagation theory in a time-space diagram and from experimental evidence in the ensemble-averaged sense. Time-averaged heat transfer distributions are evaluated and compared with experimental results for different flow and wake-generating conditions over a flat plate. Comparison showed that the present time-dependent calculations yield more accurate results than existing steady superposition models. [S0889-504X(00)00901-6]
The Evolution of the ASME Boiler and Pressure Vessel Code
Authors: Ling June
Published: July 2002

This paper describes the evolution of the ASME Boiler and Pressure Vessel Code from its inception in 1911 to the year 2000. It begins with the need of State government to protect its citizenry from the growing frequency of boiler explosions to its current stature as an international standard that facilitates global trade and commerce. A description of the major milestones in code development is provided. [S0094-9930(00)01803-5]
Tubesheet Heat Exchangers: New Common Design Rules in UPV, CODAP, and ASME
Authors: Osweiller Francis
Published: July 2002

French CODAP rules devoted to tubesheet heat exchangers were adopted in the 1990s, for the European Unfired Pressure Vessel Standard (UPV). ASME Section VIII—Div. 1 rules issued in July 1998 are based on a similar approach. At the initiative of the author, who is a member of CODAP, UPV, and ASME respective Committees on Heat Exchangers, it has been decided to make the tubesheet design rules of these three codes as consistent as possible. This paper presents the various aspects of this harmonization that covers both the theoretical basis of the rules and the editorial aspect (use of common notations, common tubesheet configurations, common terminology, etc). The main analytical basis of these rules, and their differences are explained. Numerical benchmark calculations, performed on real heat exchangers, outline the significant improvements due to the consistency, with a comparison to current TEMA rules. Use of these common rules in the coming years, both in US and Europe, is discussed in the general context of globalization of the market. [S0094-9930(00)01003-9]
Joint and Cross Acceptances for Cross-Flow-Induced Vibration—Part II: Charts and Applications
Authors: Au-Yang M. K.
Published: July 2002

Using closed-form and finite element solutions derived in Part I of this paper together with a standard commercial finite element structural-analysis computer program, the joint and cross acceptances for tubes and beams with different boundary conditions are calculated as a function of the correlation length up to 10 times the length of the structures. The results are presented in the form of charts. Steps are given to show how to use these charts together with standard commercial finite-element structural-analysis computer programs to estimate the responses of single and multi-span tubes and beams to cross-flow turbulence-induced vibration. The importance of cross-modal coupling for multi-supported beams is investigated. Examples are given. [S0094-9930(00)03303-5]
Editorial
Authors: Inman, Daniel J.
Published: July 2002

[S0739-3717(00)00101-X]
Active Mode Localization in Distributed Parameter Systems with Consideration of Limited Actuator Placement, Part 2: Simulations and Experiments
Authors: Shelley F. J. , Clark W. W.
Published: July 2002

The purpose of this two-part work is to apply active mode localization techniques to distributed parameter systems where control actuator and sensor placement is a limiting factor. In this paper, Part 2 of the study, the SVD eigenvector shaping technique examined in Part 1 is utilized to numerically and experimentally localize the response of a simply supported beam. This is done for two reasons. First, it demonstrates the application of this modified mode localization technique to a distributed parameter system. Second, it shows that it is possible to use this method to produce vibration isolation, reducing the absolute displacements in designated portions of the system while simultaneously curtailing the number of necessary control sensors and actuators. [S0739-3717(00)70302-3]
Polyetherimide (Ultem®) Spin Cast Films by XPS
Authors: Burrell Michael C. , Chera John J.
Published: July 2002

A spin cast film of polyetherimide (Ultem® 1000, GE Plastics) was analyzed by XPS using monochromatic Al Kα excitation. The measured atomic composition closely matched the expected stoichiometry of the polymer. Peak positions of the individual chemically shifted C 1s, O 1s, and N 1s components are reported. The results are in general agreement with other reported spectra of polyetherimide polymers: experimental, C 83.0%, O 12.9%, and N 4.1%; theoretical, C 82.2%, O 13.3%, and N 4.3%.
Reduction of indium segregation in InGaAs/GaAs quantum wells grown by molecular beam epitaxy on vicinal GaAs(001) substrates
Authors: Martini S. , Quivy A. A. , Tabata A. , Leite J. R.
Published: July 2002

Low-temperature photoluminescence (PL) was used to investigate the optical properties of In0.10Ga0.90As/GaAs quantum wells grown on GaAs(001) substrates with a miscut angle of 0° (nominal), 2°, 4° and 6° towards [110]. The luminescence from the quantum wells grown on a vicinal surface exhibited a blueshift compared to the nominal case. An extra emission at low energy was only observed for the nominal sample and was related to In segregation. Its absence from the PL spectrum of quantum wells grown on vicinal surfaces is a strong indication that In segregation is modified on this type of surface. Theoretical calculations confirmed our experimental data.
Thickness dependence of Y2O3 films grown on an oxidized Si surface
Authors: Cho M.-H. , Ko D.-H. , Choi Y. K. , Lyo I. W. , Jeong K. , Whang C. N. , Kim H. J. , Noh D. Y.
Published: July 2002

Heteroepitaxial Y2O3 films were grown on oxidized Si(111) and Si(100) substrates by ion assisted evaporation in ultrahigh vacuum. Film qualities such as the crystallinity, the film strain, and the morphological characteristics were investigated using x-ray scattering methods. The crystallinity of the films was investigated by reflection of high energy electron diffraction and x-ray diffraction. The morphological characteristics of the surface and interface were investigated by x-ray reflection and atomic force microscopy. From extraction of the interface and surface characteristics with the film thickness, the structural characteristics of the Y2O3 films grown on the oxidized Si(111) showed that a mosaic structure is formed at the interfacial area. The mosaic structure was minimized as the film thickness was increased. The morphological coherences between film and substrate, the strain change, and the sharp diffraction peak showed that the film surface of Y2O3(111) grown on a mosaic structure had a perfect crystalline structure and flat surface. This crystalline structure changed into a grain growth structure as the film thickness increased. However, the changes in the morphological coherence, the crystallinity, and the strain of the growth system of Y2O3(110)/Si(100) with the film thickness suggest that the film was grown with grain like islands in all the thickness ranges.
Electron-beam-assisted evaporation of epitaxial CeO2 thin films on Si substrates
Authors: Inoue Tomoyasu , Yamamoto Yasuhiro , Satoh Masataka
Published: July 2002

Electron-beam-assisted evaporation is a way to lower the growth temperature and improve crystalline quality of CeO2(110) layers on Si(100) substrates. The electron-beam-assisted evaporation system is constructed utilizing an electron-beam-irradiation system with a suppressor electrode around the sample holder. The suppressor bias condition is optimized as a function of acceleration energy of assisting electrons. The epitaxial growth quality depends on the assisting electron-beam energy. Optimum electron energy is experimentally determined to be around 360 eV, wherein the epitaxial temperature is lowered to 710 °C, i.e., temperature lowering of more than 100 °C compared with the conventional growth method.
Characterization of titanium nitride etch rate and selectivity to silicon dioxide in a Cl2 helicon-wave plasma
Authors: Chiu H. K. , Lin T. L. , Hu Y. , Leou K. C. , Lin H. C. , Tsai M. S. , Huang T. Y.
Published: July 2002

The effects of Cl2 and N2 flow rate, substrate bias power, and reaction pressure on both the titanium nitride and SiO2 etch rate plus the etch selectivity of TiN/SiO2 in a high-density helicon-wave plasma were studied. It was found that the bias power has the greatest effect on etch rate and selectivity, followed by the reaction pressure. As the bias power increased, both the TiN and SiO2 etch rate increased significantly. This result is consistent with the fact that the dominant etch mechanism for both SiO2 and TiN is an ion-assisted energy driven etch mechanism rather than pure chemical etching. As the SiO2 etch rate is drastically reduced from 403 Å/min to near zero when the bias power is decreased from 70 to 20 W, the etch selectivity of TiN to SiO2 significantly rises from 55 to over 500. The effect of pressure was found to be more complex, having a different effect on the etch rate of TiN versus SiO2. By increasing the pressure from 2.5 to 4 mTorr, the TiN etching rate rose to a maximum at 4 mTorr and then monotonically decreased up to a pressure of 10 mTorr. This result is similar to aluminum etching in a Cl2/BCl3 helicon-wave plasma. In contrast to the TiN etch behavior, the etch rate of SiO2 increased monotonically over the full pressure range investigated. In addition to the effect on etch rate, the etch selectivity of TiN to SiO2 noticeably increased with increasing pressure. Optical-emission spectroscopy was used to investigate the cause. It was determined that the effect of pressure on etch rate and selectivity could be explained by the change of atomic Cl radical density, ion flux, and ion energy. It was also observed that both the etch rate of TiN and SiO2 slightly increased as Cl2 flow rate increased from 10 to 90 sccm, reaching a maximum at about 70 sccm. The selectivity of TiN to SiO2 remained around 8–11 in this Cl2 flow rate range. The addition of N2 seems to have only a small effect on etch rate.
Microwave-assisted chemical vapor deposition process for synthesizing carbon nanotubes
Authors: Kuo Teng-Fan , Juang Zhen-Yu , Tsai Chuen-Horng , Tsau You-Ming , Cheng Hsiu-Fung , Lin I-Nan
Published: July 2002

A chemical vapor deposition (CVD) process is described that uses a susceptor to absorb the microwave and self-generate the heat for growing carbon nanotubes (CNTs) on a Si substrate. A high deposition rate of CNTs over a large area has been achieved, compared to the conventional CVD process, in which the reaction chamber was heated to the growing temperature (∼1100 °C) to trigger the reaction between the CH4 gas species and the catalyst. The modified CVD process possesses a pronounced advantage in the simplicity of the react on chamber design because no external heating is required. The size of the substrate is, in principle, unlimited as long as the susceptors can absorb the microwave uniformly. However, the design of the processing chamber and the choice of susceptors are very critical for successfully growing the CNTs using such a microwave-assisted CVD process.
X-ray photoelectron spectroscopy investigation of sidewall passivation films formed during gate etch processes
Authors: Desvoivres L. , Vallier L. , Joubert O.
Published: July 2002

We have used x-ray photoelectron spectroscopy (XPS) to investigate the composition of sidewall passivation films formed during the plasma patterning of 0.1 μm silicon gates in a high density plasma source, as a function of plasma operating conditions for HBr, Cl2, and O2 based chemistry. XPS analyses clearly show that sidewall passivation films SiXxOy (X=Br, Cl, x+2y⩽4) are formed during the main step of the gate etch process and become oxidized at the early stage of the overetch step leading to an oxidelike layer after halogen desorption. Sidewall passivation films are thicker under HBr based chemistry than under chlorine containing chemistries. In addition, the film thickness seems to be highly sensitive to oxygen dilution in HBr based plasma. These results are discussed in view of the critical dimension deviation budget bearable in sub-0.1 μm gate fabrication.
Refractive indices change at 633 nm of antimony thin films prepared by heliconwave-plasma sputtering method
Authors: Shima Takayuki , Kim Jooho , Tominaga Junji , Atoda Nobufumi
Published: July 2002

Antimony (Sb) films were prepared by heliconwave-plasma sputtering method. Refractive indices change of Sb films was examined as functions of the film thickness (3.5–100 nm) and sputtering pressure (0.2–0.8 Pa). As the thickness increased from 5 to 15 nm, the phase of the film transformed from amorphous into crystalline and the extinction coefficient k significantly increased from about 3 to 5. Amorphous thin films transformed also into crystalline state by annealing at ∼200 °C and was observed as changes in reflectivity and refractive indices. As the thickness further increased from 15 to 100 nm, the film remained crystalline, however the coefficient k oppositely decreased to the value close to that of the amorphous state (3–4) for films prepared at high sputtering pressure (0.4–0.8 Pa). Furthermore, refractive index n decreased monotonically from about 4 to 2–3 as the film thickness increased and was less dependent on the sputtering pressure.
High characteristic temperature (T=243 K) of stacked InGaAs quantum wire lasers grown on (775)B GaAs substrates by molecular beam epitaxy
Authors: Ohno Yasuhide , Kanamori Hironori , Shimomura Satoshi , Hiyamizu Satoshi
Published: July 2002

Stacked In0.15Ga0.85As quantum wire (QWR) laser structures were grown on (775)B-oriented GaAs substrates by molecular beam epitaxy. The laser active region consists of three 2.4-nm-thick QWR layers separated by thin (0.5 or 1 nm thick) AlAs barriers. It showed better one-dimensionality than that of nonstacked (775)B QWRs. The stacking (775)B QWR lasers oscillated at room temperature with the threshold current density of about 3 kA/cm2 under the pulsed current condition. They showed the characteristic temperature of T0∼243 K in the temperature range of 20–80 °C, which is very high not only T0 values of previous (775)B QWR lasers but also among those of the low-dimensional quantum structure lasers reported so far.