bluuebunny/crossref_metadata_2025 huggingface dataset:
Training Needs Assessment Data‐gathering Methods: Part 3, Focus Groups
Authors: McClelland Samuel B.
Published: July 2002

Explores four training needs assessment (TNA) data‐gathering methods:
survey questionnaires, individual interviews, focus groups, and on‐site
observations. Originally presented in condensed format in an article
entitled “Training Needs Assessment: An ‘Open‐systems’ Application”,
published in the Journal of European Industrial Training, Vol. 17 No. 1,
presents the focus group method as a means for identifying
organizational training needs. Presents and discusses relevant research
into behavioural and group dynamics, moderator skill(s) requirements,
group structure, composition, methods of interaction between the
moderator and the group, teleconferencing as a variation of the focus
group method, and analysis of the data. Concludes with the necessity of
using focus groups in conjunction with another more numerically‐oriented
method such as survey/ questionnaires in order to produce an objective
balance of both qualitative as well as quantitative training data.
Contours of diversity management and triple loop learning
Authors: Flood Robert L. , Romm Norma R.A.
Published: July 2002

Introduces diversity management as managing the increased diversity of issues that confront humankind in contemporary organizational and societal affairs. Defines triple loop learning as being about the increase in the fullness and deepness of learning about the diversity of issues and dilemmas faced. Presents the contours of diversity management and triple loop learning. Sees the latter as the dénouement of single loop learning and of double loop learning. Provides a “quickmap” of the contours of diversity management and triple loop learning.
Healthy schools, robust schools and academic emphasis as an organizational theme
Authors: Licata Joseph W. , Harper Gerald W.
Published: July 2002

Positive interpersonal relations among students, teachers and administrators that help the school meet the demands of its environment have been described as organizational health. When schools operate in ways that regularly result in student and teacher empathy and involvement, they can be considered relatively robust organizations. This study employed a sample of 38 junior high and middle schools to test a hypothesis predicting a significant positive relationship between school health and robustness. Multiple regression analysis tended to support this hypothesis, suggesting a positive association between teachers’ perceptions of organizational health and environmental robustness. However, only one school health measure, teachers’ perceptions of a healthy school‐level emphasis on the academic success of their students, made a significant and separate contribution to the overall relationship between school health and robustness. Apparently, when schools are healthy and robust, academic emphasis is a predominant organizational theme.
Tourists’ perceptions towards and satisfaction with service quality in the cross‐cultural service encounter: implications for hospitality and tourism management
Authors: Weiermair Klaus
Published: July 2002

This article develops a comprehensive cultural construct to explain and forecast tourists’ behaviour and quality judgements. A destination value chain is depicted to capture the possible influence of culture and cultural values on tourism behaviour. Cultural norms have an impact on both tourists’ expectations and their perceptions of received service quality for any of the six service elements frequently employed in tourism analyses. Tourism service encounters take place in the context of a tourism culture which is formed by four components: the national/regional settings of the tourist and the host region, the tourists’ various subcultures and the organisational culture of tourism enterprises in the tourism receiving region. A differentiated approach is developed which distinguishes between global, national and sub‐national cultural constructs.
The culture and quality of higher education institutions: examining the links
Authors: Lomas Laurie
Published: July 2002

A more rigid and specific quality management system in higher education institutions (HEIs) is developing under the auspices of the Quality Assurance Agency. The use of models of organisational culture suggest that organisation cultures vary greatly in the higher education sector. Within each HEI there is a mosaic of sub‐cultures making it very difficult to discern what is the dominant culture. The author’s initial analysis of an empirical study of seven HEIs points up the great variance of culture which emanates from differing mission statements, aims and objectives, size and nature of student intake, range of courses and emphasis on research. This article questions whether the developing quality management approach based on standards and benchmarks can gauge accurately and fairly the quality of provision in such a variety of HEIs.
Toward effective use of cause‐related marketing alliances
Authors: Till Brian D. , Nowak Linda I.
Published: July 2002

Companies have become increasingly active in developing relationships between their brands and popular causes in such areas as the environment (e.g. nature conservancy) and health issues (e.g. breast cancer awareness crusade). As such alliances become a more important strategic component of the brand’s marketing mix, managers seek direction as to how to generate the most impact with these tie‐ins. This article uses associative learning principles as a framework for understanding how to facilitate building connections between brands and causes so as to increase the value of this highly visible marketing activity. Specific associative learning principles are detailed and applied, improving the use of cause‐related marketing alliances.
Moving beyond fit: the role of brand portfolio characteristics in consumer evaluations of brand reliability
Authors: DelVecchio Devon
Published: July 2002

Brand extensions allow consumers to use past experiences with the brand in order to assess the extension and thereby reduce the risk associated with purchasing a new product. In considering the ability of a brand to mitigate the risk associated with an extension (a construct herein referred to as brand reliability), prior research has focused on the role of fit between the brand and the extension category. In the present study, results indicate that in addition to fit, characteristics of the brand portfolio (number of products affiliated with the brand and the quality variance of these products) play an important role in affecting consumer impressions of brand reliability. In contrast to prior research that forwards that brands become diluted by offering extensions, the present results suggest that having a greater number of products affiliated with the brand has positive consequences when consumers evaluate a new extension.
Comprehensive criteria to judge validity and reliability of qualitative research within the realism paradigm
Authors: Healy Marilyn , Perry Chad
Published: July 2002

Aims to address a gap in the literature about quality criteria for validity and reliability in qualitative research within the realism scientific paradigm. Six comprehensive and explicit criteria for judging realism research are developed, drawing on the three elements of a scientific paradigm of ontology, epistemology and methodology. The first two criteria concern ontology, that is, ontological appropriateness and contingent validity. The third criterion concerns epistemology: multiple perceptions of participants and of peer researchers. The final three criteria concern methodology: methodological trustworthiness, analytic generalisation and construct validity. Comparisons are made with criteria in other paradigms, particularly positivism and constructivism. An example of the use of the criteria is given. In conclusion, this paper’s set of six criteria will facilitate the further adoption of the realism paradigm and its evaluation in marketing research about, for instance, networks and relationship marketing.
Calibration of shrinkage and beam offset in SLS process
Authors: Wang Xiangwei
Published: July 2002

Selective laser sintering (SLS) is one of the most successful rapid tooling processes. Shrinkage and beam offset are the two most important control parameters in this process. First, the SLS process and procedure of calibration are described. Second, based on the property of shrinkage and beam offset, a basic formula of shrinkage and beam offset is derived. Finally, the procedure of applying shrinkage (scaling factor) and beam offset is described.
Bank lending valuations on commercial property – Does European mortgage lending value add anything to the process?
Authors: Crosby Neil , French Nick , Oughton Melanie
Published: July 2002

This paper reviews a number of alternative bases of valuation which can be applied for lending purposes. In early 1999, the European Mortgage Federation suggested that the philosophy of a European Mortgage Lending Value (EMLV) should be based on “sustainable” values and this recommendation is compared to the current basis used for bank lending valuations, mainly market value. This comparison is of both concepts and applications. In addition, concepts and applications of worth valuations are considered. The paper concentrates on commercial property but many of the principles also apply to residential property valuations. The paper concludes that the EMLV concept of sustainable values is itself unsustainable. There are a number of reasons for this view, not least that the concept itself cannot be closely defined and will be interpreted differently by those who apply it. It lacks the objectivity of market value and the rationality of concepts of worth. The paper also questions whether any concept of value can apply over a period of time and suggests that all other “values” do not have a shelf life and relate to one specific point in time only. In application, in the absence of any meaningful conceptual basis, sustainable value appears to have been applied as a conservative market value. It may give the illusion of having some extended time horizon attached to it but this is the major danger. The reality is that it is just another product of the endless search for a single valuation figure which can give lenders the holy grail of longer‐term protection from lender default. This it will fail to do as all other bases applied so far to lending valuations have done. The recommendations of this paper are that all European institutions and valuer/appraisers resist this latest incursion into the fruitless search for the perfect loan valuation basis and concentrate on the other aspects of the valuation which can truly help lenders make their decisions. These are the economic, property market and occupier issues which should be considered by the appraiser and included as major items in valuation reports, many of which would be explicitly included in a full discounted cash flow approach to commercial property loan valuations.
Sorting out access and neighbourhood factors in hedonic price modelling
Authors: Des Rosiers François , Thériault Marius , Villeneuve Paul‐Y
Published: July 2002

This paper investigates the analytical potential of factor analysis for sorting out neighbourhood and access factors in hedonic modelling using a simulation procedure that combines GIS technology and spatial statistics. An application to the housing market of the Quebec Urban Community (575,000 in population; study based on some 2,400 cottages transacted from 1993 to 1997) illustrates the relevance of this approach. In the first place, accessibility from each home to selected activity places is computed on the basis of minimum travelling time using the TransCAD transportation‐oriented GIS software. The spatial autocorrelation issue is then addressed and a general modelling procedure developed. Following a five‐step approach, property specifics are first introduced in the model; proximity and neighbourhood attributes are then successively added on. Finally, factor analyses are performed on each set of access and census variables, thereby reducing to six principal components an array of 49 individual attributes. Substituting the resulting factors for the initial descriptors leads to high model performances, controlled collinearity and stable hedonic prices, although remaining spatial autocorrelation is still detected in the residuals.
Effect of the N1 residue on the stability of the α‐helix for all 20 amino acids
Authors: Cochran Duncan A.E. , Penel Simon , Doig Andrew J.
Published: July 2002

N1 is the first residue in an α‐helix. We have measured the contribution of all 20 amino acids to the stability of a small helical peptide CH3CO‐XAAAAQAAAAQAAGY‐NH2 at the N1 position. By substituting every residue into the N1 position, we were able to investigate the stabilizing role of each amino acid in an isolated context. The helix content of each of the 20 peptides was measured by circular dichroism (CD) spectroscopy. The data were analyzed by our modified Lifson‐Roig helix‐coil theory, which includes the n1 parameter, to find free energies for placing a residue into the N1 position. The rank order for free energies is Asp−, Ala > Glu− > Glu0 > Trp, Leu, Ser > Asp0, Thr, Gln, Met, Ile > Val, Pro > Lys+, Arg, His0 > Cys, Gly > Phe > Asn, Tyr, His+. N1 preferences are clearly distinct from preferences for the preceding N‐cap and α‐helix interior. pKa values were measured for Asp, Glu, and His, and protonation‐free energies were calculated for Asp and Glu. The dissociation of the Asp proton is less favorable than that of Glu, and this reflects its involvement in a stronger stabilizing interaction at the N terminus. Proline is not energetically favored at the α‐helix N terminus despite having a high propensity for this position in crystal structures. The data presented are of value both in rationalizing mutations at N1 α‐helix sites in proteins and in predicting the helix contents of peptides.
Three‐dimensional structures of the three human class I alcohol dehydrogenases
Authors: Niederhut Monica S. , Gibbons Brian J. , Perez‐Miller Samantha , Hurley Thomas D.
Published: July 2002

In contrast with other animal species, humans possess three distinct genes for class I alcohol dehydrogenase and show polymorphic variation in the ADH1B and ADH1C genes. The three class I alcohol dehydrogenase isoenzymes share ∼93% sequence identity but differ in their substrate specificity and their developmental expression. We report here the first three‐dimensional structures for the ADH1A and ADH1C*2 gene products at 2.5 and 2.0 Å, respectively, and the structure of the ADH1B*1 gene product in a binary complex with cofactor at 2.2 Å. Not surprisingly, the overall structure of each isoenzyme is highly similar to the others. However, the substitution of Gly for Arg at position 47 in the ADH1A isoenzyme promotes a greater extent of domain closure in the ADH1A isoenzyme, whereas substitution at position 271 may account for the lower turnover rate for the ADH1C*2 isoenzyme relative to its polymorphic variant, ADH1C*1. The substrate‐binding pockets of each isoenzyme possess a unique topology that dictates each isoenzyme's distinct but overlapping substrate preferences. ADH1*B1 has the most restrictive substrate‐binding site near the catalytic zinc atom, whereas both ADH1A and ADH1C*2 possess amino acid substitutions that correlate with their better efficiency for the oxidation of secondary alcohols. These structures describe the nature of their individual substrate‐binding pockets and will improve our understanding of how the metabolism of beverage ethanol affects the normal metabolic processes performed by these isoenzymes.
Kinetic properties and inhibition of the dimeric dUTPase‐dUDPase from Leishmania major
Authors: Hidalgo‐Zarco Fernando , Camacho Ana G. , Bernier‐Villamor Victor , Nord Johan , Ruiz‐Pérez Luis Miguel , González‐Pacanowska Dolores
Published: July 2002

Kinetic properties of the dimeric enzyme dUTPase from Leishmania major were studied using a continuous spectrophotometric method. dUTP was the natural substrate and dUMP and PPi the products of the hydrolysis. The trypanosomatid enzyme exhibited a low Km value for dUTP (2.11 μM), a kcat of 49 s−1, strict Michaelis–Menten kinetics and is a potent catalyst of dUDP hydrolysis, whereas in other dUTPases described, this compound acts as a competitive inhibitor. Discrimination is achieved for the base and sugar moiety showing specificity constants for different dNTPs similar to those of bacterial, viral, and human enzymes. In the alkaline range, the Km for dUTP increases with the dissociation of ionizable groups showing pKa values of 8.8, identified as the uracil moiety of dUTP and 10, whereas in the acidic range, Km is regulated by an enzyme residue exhibiting a pKa of 7.1. Activity is strongly inhibited by the nucleoside triphosphate analog α‐β‐imido‐dUTP, indicating that the enzyme can bind triphosphate analogs. The existence of specific inhibition and the apparent structural and kinetic differences (reflected in different binding strength of dNTPs) with other eukaryotic dUTPases suggest that the present enzyme might be exploited as a target for new drugs against leishmaniasis.
Prenatal nicotine exposure increases apnoea and reduces nicotinic potentiation of hypoglossal inspiratory output in mice
Authors: Robinson Dean M. , Peebles Karen C. , Kwok Henry , Adams Brandon M. , Clarke Lan‐Ling , Woollard Gerald A. , Funk Gregory D.
Published: July 2002

We examined the effects of in utero nicotine exposure on postnatal development of breathing pattern and ventilatory responses to hypoxia (7.4 % O2) using whole‐body plethysmography in mice at postnatal day 0 (P0), P3, P9, P19 and P42. Nicotine delayed early postnatal changes in breathing pattern. During normoxia, control and nicotine‐exposed P0 mice exhibited a high frequency of apnoea (fA) which declined by P3 in control animals (from 6.7 ± 0.7 to 2.2 ± 0.7 min−1) but persisted in P3 nicotine‐exposed animals (5.4 ± 1.3 min−1). Hypoxia induced a rapid and sustained reduction in fA except in P0 nicotine‐exposed animals where it fell initially and then increased throughout the hypoxic period. During recovery, fA increased above control levels in both groups at P0. By P3 this increase was reduced in control but persisted in nicotine‐exposed animals. To examine the origin of differences in respiratory behaviour, we compared the activity of hypoglossal (XII) nerves and motoneurons in medullary slice preparations. The frequency and variability of the respiratory rhythm and the envelope of inspiratory activity in XII nerves and motoneurons were indistinguishable between control and nicotine‐exposed animals. Activation of postsynaptic nicotine receptors caused an inward current in XII motoneurons that potentiated XII nerve burst amplitude by 25 ± 5 % in control but only 14 ± 3 % in nicotine‐exposed animals. Increased apnoea following nicotine exposure does not appear to reflect changes in basal activity of rhythm or pattern‐generating networks, but may result, in part, from reduced nicotinic modulation of XII motoneurons.
Presynaptic short‐term depression is maintained during regulation of transmitter release at a GABAergic synapse in rat hippocampus
Authors: Hefft Stefan , Kraushaar Udo , R. P. Geiger Jörg , Jonas Peter
Published: July 2002

To examine possible interactions between fast depression and modulation of inhibitory synaptic transmission in the hippocampus, we recorded from pairs of synaptically connected basket cells (BCs) and granule cells (GCs) in the dentate gyrus of rat brain slices at 34 °C. Multiple‐pulse depression (MPD) was examined in trains of 5 or 10 inhibitory postsynaptic currents (IPSCs) evoked at frequencies of 10–00 Hz under several conditions that inhibit transmitter release: block of voltage‐dependent Ca2+ channels by Cd2+ (10 μm), activation of γ‐amino‐butyric acid type B receptors (GABABRs) by baclofen (10 μm) and activation of muscarinic acetylcholine receptors (mAchRs) by carbachol (2 μm). All manipulations led to a substantial inhibition of synaptic transmission, reducing the amplitude of the first IPSC in the train (IPSC1) by 72 %, 61 % and 29 %, respectively. However, MPD was largely preserved under these conditions (0.34 in control versus 0.31, 0.50 and 0.47 in the respective conditions at 50 Hz). Similarly, a theta burst stimulation (TBS) protocol reduced IPSC1 by 54 %, but left MPD unchanged (0.40 in control and 0.39 during TBS). Analysis of both fractions of transmission failures and coefficients of variation (CV) of IPSC peak amplitudes suggested that MPD had a presynaptic expression site, independent of release probability. In conclusion, different types of presynaptic modulation of inhibitory synaptic transmission converge on a reduction of synaptic strength, while short‐term dynamics are largely unchanged.
Multiobjective Weighting Selection for Optimization-Based Control Design
Authors: Takahashi Ricardo H. C. , Camino and Juan F. , Zampieri Douglas E. , Peres Pedro L. D.
Published: July 2002

A methodology for the multiobjective design of controllers is presented, motivated by the problem of designing an active suspension controller. This problem has, as a particular feature, the possibility of being defined with two design variables only. The multiobjective controller is searched inside the space of “optimal controllers” defined by a weighted cost functional. The weightings are taken as the optimization variables for the multiobjective design. The method leads to (local) Pareto-optimal solutions and allows the direct specification of controller constraints in terms of some primary objectives which are taken into account in the multiobjective search. [S0022-0434(00)01403-9]
A Method of Correlating Fully Developed Turbulent Friction in Triangular Ducts
Authors: Nan S. F. , Dou M.
Published: July 2002

Fanning factors in isosceles-triangular ducts are examined. Data obtained in the literature were examined for deviations from the smooth circular tube line. It was found that the constant C in a form of the Blasius equation 4f Re0.25=C decreases as the apex angle does within the extent of experiments, and has 20 percent low deviation at 4 degree. For the apex angles greater than 60 degree, it was found that the constant C decreases as the apex angle increases. It is thus concluded that the hydraulic diameter is not the proper length dimension to use in the Reynolds number to insure similarity between the circular and triangular ducts. Instead, if an area equivalent round diameter is used in the Reynolds number, the deviations from the smooth circular tube line is within ∼6 percent. By using this area equivalent round diameter, it is demonstrated that circular tube methods may be readily applied to triangular ducts eliminating large errors in estimation of friction factors. [S0098-2202(00)00503-4]
From Heat Transfer Principles to Shape and Structure in Nature: Constructal Theory
Authors: Bejan Adrian
Published: July 2002

This lecture reviews a relatively recent body of heat transfer work that bases on a deterministic (constructal) principle the occurrence of geometric form in systems with internal flows. The same principle of global optimization subject to constraints allow us to anticipate the natural (animate and inanimate) flow architectures that surround us. The lecture starts with the example of the optimal spatial distribution of material (e.g., heat exchanger equipment) in power plants. Similarly, void space can be allocated optimally to construct flow channels in the volume occupied by a heat generating system. The lecture continues with the optimization of the path for heat flow between a volume and one point. It shows that when the heat flow can choose between at least two paths, low conductivity versus high conductivity, the optimal flow structure for minimal global resistance in steady flow is a tree. Nearly the same tree is deduced by minimizing the time of discharge in the flow from a volume to one point. Analogous tree-shaped flows are constructed in pure fluid flows, and in flow through a heterogeneous porous medium. The optimization of trees that combine heat transfer and fluid flow is illustrated by means of two-dimensional trees of plate fins. The method is extended to the superposition of two fluid trees in counterflow, as in vascularized tissues under the skin. The two trees in counterflow are one tree of convective heat currents that effect the loss of body heat. It is shown that the optimized geometry of the tree is responsible for the proportionalities between body heat loss and body size raised to the power 3/4, and between breathing time and body size raised to the power 1/4. The optimized structures are robust with respect to changes in some of the externally specified parameters. When more degrees-of-freedom are allowed, the optimized structure looks more natural. The lecture outlines a unique opportunity for engineers to venture beyond their discipline, and to construct an engineering theory on the origin and workings of naturally organized systems. [S0022-1481(00)02403-8]
A Frequency and Curvature Based Experimental Method for Locating Damage in Structures
Authors: Ratcliffe Colin P.
Published: July 2002

This paper presents a method for locating structural damage using experimental vibration data. The method uses measured frequency response functions to obtain displacement as a function of frequency. The displacement functions are converted to curvature functions, which are further processed to yield a damage index, displayed on a plot of position versus frequency. The method can be applied when there is no a priori knowledge about the undamaged structure, and it is suitable for automation. This paper details the theory of the broadband method, and the results of an experimental demonstration in which a steel beam was damaged with a narrow slot. It is shown that this proposed damage detection method is highly sensitive, and can locate a very small amount of damage. For example, the narrow slot was correctly located when there was only a 0.8 percent reduction in thickness in the beam. Traditionally, damage causes a change in natural frequencies, but at this small level of damage the frequency changes were within experimental error. Other published methods failed to locate the slot until it was significantly deeper. [S0739-3717(00)01403-3]
Elastohydrodynamic Film Collapse During Rapid Deceleration. Part II—Theoretical Analysis and Comparison of Theory and Experiment
Authors: Glovnea R. P. , Spikes H. A.
Published: July 2002

This paper presents a theoretical model for the behavior of elastohydrodynamic films subjected to transient speed conditions, based on Grubin’s analytical solution for elastohydrodynamic lubrication. This model is applied to predict film thickness in high deceleration conditions. The model’s predictions are compared with the experimental results presented in an accompanying paper entitled “Elastohydrodynamic Film Collapse During Rapid Deceleration. Part I: Experimental Results.”
Closure to “Discussion of ‘Response Bounds for Linear Damped Systems’ ” (2000, ASME J. Appl. Mech., 67, p. 636)
Authors: Hu Bin , Eberhard Peter
Published: July 2002

[S0021-8936(00)03803-4]
Experimental and Numerical Investigations on the Influence of Tooth Friction in Spur and Helical Gear Dynamics
Authors: Velex P. , Cahouet V.
Published: July 2002

A model based upon a finite element procedure is introduced for analyzing the influence of tooth friction on spur and helical gear dynamics. The equations of motion are solved by combining a time-step integration method with several iterative algorithms aimed at satisfying normal and tangential contact conditions. Comparisons between simulated and measured quasi-static bearing forces are satisfactory and largely validate the theoretical developments. Results also reveal the potentially significant contribution of tooth friction to gear vibration and noise. Simulations are then extended to high speeds and the interest of considering both transmission error and tooth friction excitations to achieve silent gears is discussed. [S1050-0472(00)02804-X]
The Elastic Cable Under the Action of Concentrated and Distributed Forces
Authors: Sagatun Svein I.
Published: July 2002

This article contains a recursive analytical expression for the static solution of an elastic cable under the action of concentrated and distributed forces in three dimensions. The cable’s axial stiffness as well as the concentrated and distributed forces may vary along the cable. The proposed solution is presented on vectorial form; it is exact and faster than a finite-element-based solution.
Rough Wall Modification of Two-Layer k−ε
Authors: Durbin P. A. , Medic G. , Seo J.-M. , Eaton J. K. , Song S.
Published: July 2002

A formulation is developed to apply the two-layer k−ε model to rough surfaces. The approach involves modifying the lν formula and the boundary condition on k. A hydrodynamic roughness length is introduced and related to the geometrical roughness through a calibration procedure. An experiment has been conducted to test the model. It provides data on flow over a ramp with and without surface roughness.
Real and Misconceived Limitations to Decision Based Design With Utility Analysis
Authors: Thurston Deborah L.
Published: July 2002

Decision based design shows great promise in improving the design process, but is not a panacea. The design problem of interest here is tradeoffs between conflicting objectives, particularly under uncertainty. The focus is on multiattribute utility theory. This paper describes several real limitations to utility analysis in the context of engineering design, and attempts to clear up several common misconceptions about it. The real limitations are in the initial configuration and analytic design phases, and in overcoming difficulties in group decision making. The major misconceptions relate to independence conditions, the functional form and assessment biases.
Acceleration of Anisotropic Scattering Computations Using Coupled Ordinates Method (COMET)
Authors: Mathur S. R. , Murthy J. Y.
Published: July 2002

Traditional sequential solution procedures for solving coupled heat transfer and radiation problems are known to perform very poorly when the optical thickness is high. This poor performance can be traced to the fact that sequential procedures cannot handle strong inter-equation coupling resulting from large absorption and scattering coefficients. This paper extends the use of the coupled ordinates method (COMET) to problems involving anisotropic scattering, where inter-equation coupling results from the in-scattering terms. A finite volume formulation for arbitrary unstructured meshes is used to discretize the radiative transfer equation. An efficient point-solution procedure is devised which is suitable for different scattering phase functions, and eliminates the cubic dependence of the operation count on the angular discretization. This solution scheme is used as a relaxation sweep in a multigrid procedure designed to eliminate long-wavelength errors. The method is applied to scattering problems and shown to substantially accelerate convergence for moderate to large optical thicknesses.
Off-Axis Torsion Tests on Tubular Specimens of Steel
Authors: Takeda Takenobu , Chen Zhongchun
Published: July 2002

In order to analyze the anisotropic hardening behavior of metals, an off-axis torsion test by combined loading is developed. In this test, the maximum shear stress direction φ can be changed from 0 deg to 90 deg while the ratio of maximum and minimum principal stresses is kept at −1. With increasing angle φ, the yield stress of the torsional-prestrained steel decreases; the difference between the directions of the maximum shear stress and principal shear strain increment rises to a maximum value and then decreases. It is experimentally verified that anisotropy is more severe when a smaller offset strain is used in defining the yield stress.
Flamelet Model of NOx in a Diffusion Flame Combustor
Authors: Volkov D. V. , Belokin A. A. , Lyubimov D. A. , Zakharov V. M. , Opdyke, G.
Published: July 2002

This paper describes a model used for the prediction of the formation of nitrogen oxides in modifications of an industrial diffusion flame, natural gas fueled can combustor. The flowfield inside the modified combustors is calculated using a Navier-Stokes solver. A fast chemistry assumption is used for modeling the heat release. Calculated turbulence parameters are then used for the calculation of the NOx formation rate in the post-processing mode with the aid of a flamelet model. The flamelet model permits the use of detailed kinetics with only minimal computational expense. The dependence of the NOx formation rate on the mixture fraction and scalar dissipation is calculated separately for each given condition. The validation of the model predictions is based on field test data taken earlier on several low NOx modifications recently applied to an industrial, reverse flow can type combustor. The reduced level of NOx emissions was achieved in these modifications by changes in the air distribution within the combustor liner. A comparison of the predicted and measured NOx emission levels shows good potential of the flamelet model.
Identification of Hardening Parameters of Metals From Spherical Indentation Tests
Authors: Kucharski S. , Mro´z Z.
Published: July 2002

The identification method of hardening parameters specifying stress-strain curve is proposed by applying spherical indentation test and measuring the penetration depth during loading and unloading. The loading program is composed of a geometric sequence of loading and partial unloading steps from which the variation of permanent penetration with load level is determined. This data is used for specification of two parameters k and m occurring in the plastic hardening curve εp=σ/k1/m, where εp denotes the plastic strain.
Bouncing-Ball Model of ‘Dry’ Motions of a Tethered Buoy
Authors: Plaut R. H. , Farmer A. L. , Holland M. M.
Published: July 2002

The motions of a buoy moored to the sea floor by a cable are considered. The buoy is modeled both as a point mass and as a sphere. It is assumed that the mooring line has no effect when it is slack, and that when it becomes taut it exerts an instantaneous impulsive force on the buoy, analogous to the impact of a ball bouncing on a rigid surface. The magnitude of the axial component of the velocity is reduced at this time. Fluid inertia and damping are not included, and the wave forces are assumed to be harmonic. The effects of the coefficient of restitution and the forcing frequency on two types of critical force are examined. Trajectories of the motion are plotted and the impact velocities are computed and analyzed. Knowledge of the number and magnitude of these impacts is useful in assessing fatigue of the mooring line.
NO

x

and N2O Formation Mechanisms—A Detailed Chemical Kinetic Modeling Study on a Single Fuel Particle in a Laboratory-Scale Fluidized Bed
Authors: Lo¨ffler Gerhard , Andahazy Dietmar , Wartha Christian , Winter Franz , Hofbauer Hermann
Published: July 2002

NO x (i.e., NO and NO2) and N2O are known as harmful pollutants. In fluidized bed combustion these are formed from the nitrogen in the fuel. To develop effective primary measures reducing the emissions, more knowledge on the mechanism of formation and destruction ongoing in fluidized beds has to be obtained. In this work, a detailed chemistry model is combined with a two-phase model for a stationary fluidized bed to calculate the emissions of a single fuel particle in a laboratory-scale stationary fluidized bed. The single particle model consists of a simple model for the H2O release during drying, a model for the volatiles composition, and a model for the nitrogen chemistry during char combustion. The detailed reaction mechanism consists of a homogeneous part, heterogeneously catalyzed reactions on the bed material, and radical recombination reactions on the solids’ surface. The results confirm that devolatilization and char combustion are of nearly equal importance for NO and N2O formation. During devolatilization, NO is formed from HCN and NH3, while N2O is formed almost exclusively from HCN. During char combustion, NO is mostly formed by heterogeneous oxidation of char nitrogen, while N2O is formed from homogeneous oxidation of HCN. On the other hand, there is also a back coupling of NO on the homogeneous burnout of the carbon containing species, by sensitizing the oxidation of CH4.
A Reduced-Order Model of Mistuning Using a Subset of Nominal System Modes
Authors: Yang M.-T. , Griffin J. H.
Published: July 2002

Reduced-order models have been reported in the literature that can be used to predict the harmonic response of mistuned bladed disks. It has been shown that in many cases they exhibit structural fidelity comparable to a finite element analysis of the full bladed disk system while offering a significant improvement in computational efficiency. In these models the blades and disk are treated as distinct substructures. This paper presents a new, simpler approach for developing reduced-order models in which the modes of the mistuned system are represented in terms of a subset of nominal system modes. It has the following attributes: the input requirements are relatively easy to generate; it accurately predicts mistuning effects in regions where frequency veering occurs; as the number of degrees-of-freedom increases it converges to the exact solution; it accurately predicts stresses as well as displacements; and it accurately models the deformation and stresses at the blades’ bases.
Numerical Study of Pressure Fluctuations Caused by Impeller-Diffuser Interaction in a Diffuser Pump Stage
Authors: Shi F. , Tsukamoto H.
Published: July 2002

Two-dimensional and three-dimensional, unsteady state Reynolds-averaged Navier-Stokes (RANS) equations with standard k-ε turbulence models were solved within an entire stage of a diffuser pump to investigate pressure fluctuations due to the interaction between impeller and diffuser vanes. A complete solution of transient flows due to the interaction between components in the whole pump without approximating the blade count ratio of impeller to diffuser was obtained by employing an Arbitrary Sliding Mesh. The unsteady numerical results were compared with experimental data and values calculated by the singularity method. As a result of the present study, the Navier-Stokes code with the k-ε model is found to be capable of predicting pressure fluctuations in the diffuser. Furthermore, extensive numerical studies identified sources contributing to the pressure fluctuations in the diffuser, and helped to understand the mechanism of impeller-diffuser interactions in the diffuser pump.
On Characteristic Times in Generalized Thermoelasticity
Authors: Strunin D. V.
Published: July 2002

The model of Green and Lindsay is a popular generalization of the theory of thermoelasticity incorporating second sound. Within the model the second sound is intimately linked to a presence of two characteristic times, t1 and t2, constrained by an inequality t2⩽t1. We present a modification of the theory where no constraints on the times arise.
In-Cylinder Pressure Reconstruction Based on Instantaneous Engine Speed Signal
Authors: Moro D. , Cavina N. , Ponti F.
Published: July 2002

This paper presents an original methodology for the instantaneous in-cylinder pressure waveform reconstruction in a spark-ignited internal combustion engine. The methodology is based on the existence of a linear correlation, characterized by frequency response functions, between in-cylinder pressure and engine speed signals. This correlation is experimentally verified and evaluated by simultaneous measurements of the above-mentioned quantities. The evaluation of different frequency response functions, one for each steady-state condition investigated, allows recovering the pressure waveform even under other engine running conditions (i.e., transients). In this way, during on-board operation, the pressure waveform could be recovered using only the engine speed signal, already present in current production electronic control units. In this paper the signal processing methodology and some experimental results, obtained during transient tests, are presented. The methodology could be interesting for the development of advanced engine control strategies aimed at the management of the torque generated by the engine. As an example, traction control in drive-by-wire systems could be a possible challenging application. The in-cylinder pressure reconstruction performed using the frequency response functions, in fact, allows the evaluation of the indicated torque. An important characteristic of this methodology is, furthermore, the diagnostic capability for the combustion process, that is guaranteed by the linear correlation between in-cylinder pressure and instantaneous engine speed waveforms. Also in presence of a misfiring cylinder, when the instantaneous engine speed waveform is strongly affected by the absence of combustion, the reconstructed in-cylinder pressure shows a good agreement with the measured one. The experimental tests have been conducted in a test cell using a four-cylinder production engine. It has to be noted, anyway, that the same methodology can be applied to engines with a higher number of cylinders.
Constructive Representation of Heterogeneous Objects
Authors: Shin Ki-Hoon , Dutta Debasish
Published: July 2002

This paper proposes a constructive representation scheme for heterogeneous objects (or FGMs). In particular, this scheme focuses on the construction of complicated heterogeneous objects, guaranteeing desired material continuities at all the interfaces. In order to create various types of heterogeneous primitives, we first describe methods for specifying material composition functions such as geometry-independent, geometry-dependent functions, and multiple sets of these functions. Constructive Material Composition (CMC) and corresponding heterogeneous Boolean Operators (e.g., material union, difference, intersection, and partition) are then proposed to illustrate how material continuities are dealt with. Finally, we will describe the model hierarchy and data structure for computer representation. Even though the constructive representation alone is sufficient for modeling heterogeneous objects, the proposed scheme pursues a hybrid representation between decomposition and construction. That is because hybrid representation can avoid unnecessary growth of binary trees.
Fourier Series Analysis of Epicyclic Gearbox Vibration
Authors: McNames James
Published: July 2002

Synchronous averaging is difficult to use with epicyclic gear systems because the dominant frequencies are slightly skewed and asymmetrical. This Tech Brief uses Fourier series analysis to add new insight to this phenomenon. The results are illustrated on vibration data recorded from a Cobra AH-1S helicopter gearbox.
Fluid transients and fluid-structure interaction in flexible liquid-filled piping
Authors: Wiggert David C , Tijsseling Arris S
Published: July 2002

Fluid-structure interaction in piping systems (FSI) consists of the transfer of momentum and forces between piping and the contained liquid during unsteady flow. Excitation mechanisms may be caused by rapid changes in flow and pressure or may be initiated by mechanical action of the piping. The interaction is manifested in pipe vibration and perturbations in velocity and pressure of the liquid. The resulting loads imparted on the piping are transferred to the support mechanisms such as hangers, thrust blocks, etc. The phenomenon has recently received increased attention because of safety and reliability concerns in power generation stations, environmental issues in pipeline delivery systems, and questions related to stringent industrial piping design performance guidelines. Furthermore, numerical advances have allowed practitioners to revisit the manner in which the interaction between piping and contained liquid is modeled, resulting in improved techniques that are now readily available to predict FSI. This review attempts to succinctly summarize the essential mechanisms that cause FSI, and present relevant data that describe the phenomenon. In addition, the various numerical and analytical methods that have been developed to successfully predict FSI will be described. Several earlier reviews regarding FSI in piping have been published; this review is intended to update the reader on developments that have taken place over the last approximately ten years, and to enhance the understanding of various aspects of FSI. There are 123 references cited in this review article.
Effective stress-strain relations for two-dimensional cellular sandwich cores: Homogenization, material models, and properties
Authors: Hohe and Jo¨rg , Becker Wilfried
Published: July 2002

The theory of sandwich construction has been an active field of research for more than five decades. Aim of the present article is to review the work dedicated to the theoretical determination of the effective stress-strain material behavior of two-dimensional cellular materials with large-scale cells used as core material of structural sandwich panels. Both, the applied homogenization schemes and the applied material models are considered. Explicit expressions for the linear properties of a variety of basic cell geometries are presented, as well as schemes for the analysis of more general cases. In addition, the incorporation of specific effects such as cell wall imperfections or core face sheet constraints and the analysis of nonlinear elastic and elastic-plastic effective material response are reviewed. This review article includes 148 references.
A Dynamical Systems Approach to Damage Evolution Tracking, Part 2:
Model-Based Validation and Physical Interpretation
Authors: Cusumano Joseph P. , Chelidze David , Chatterjee Anindya
Published: July 2002

In this paper, the hidden variable damage tracking method developed in Part 1 is analyzed using a physics-based mathematical model of the experimental system: a mechanical oscillator with a nonstationary two-well potential. Numerical experiments conducted using the model are in good agreement with the experimental study presented in Part 1, and explicitly show how the tracking metric is related to the slow hidden variable evolution responsible for drift in the fast system parameters. Using the idea of averaging, the slow flow equation governing the hidden variable evolution is obtained. It is shown that the solution to the slow flow equation corresponds to the hidden variable trajectory obtained with the experimental tracking method. Thus we establish in principle the relationship of our algorithm to any underlying physical process. Based on this result, we discuss the application of the tracking method to systems with evolving material damage using the results of some preliminary experiments.