bluuebunny/crossref_metadata_2025 huggingface dataset:
The creation of a management‐by‐variance tool for facilities management performance assessment
Authors: Hinks John , McNay Peter
Published: July 2002

The need to establish key performance indicators for facilities management (FM) is well recognised. However, difficulties in establishing universally‐accepted definitions of the FM function and its management process continue to confound the identification and application of a generic set of performance parameters. This paper describes the process of developing a management‐by‐variance tool for monitoring the performance of the FM function of a major financial services company. The dual problems of the absence of a standardised set of key performance indicators (KPIs) and the lack of existing data for performance evaluation were addressed using a Delphi group. The principle of management‐by‐variance is based on the monitoring and analysis of performance trends, which is done by monitoring changes in performance using a bespoke (rather than generalised) set of performance indicators. This paper describes the process of creating the pilot version of a management‐by‐variance tool in sufficient detail to allow the process to be replicated to create other sets of bespoke KPIs. The process and outcomes of the exercise to short‐list, rank, and weight a finalised list of 23 KPIs are discussed. The KPIs are analysed in the context of the method of their selection, prioritisation and weighting for their intended custom application.
The perception of lighting quality in a non‐uniformly lit office environment
Authors: Wright M.S. , Hill S.L. , Cook G.K. , Bright K.T.
Published: July 2002

This paper presents the views of 16 fully sighted people who carried out typical office tasks under eight different lighting systems. This work is taken from a much larger study, primarily involved with the lighting of office tasks for visually impaired people. Non‐parametric statistical tests show there are significant differences of opinion about the different lighting systems in terms of adequacy and comfort. Whilst there is a general trend in the results which suggest that increasing task illuminance and wall illuminance is preferred by the test subjects, other issues are identified which can influence aspects of lighting quality.
Three‐dimensional finite element analysis for hollow section extrusion of a triply‐connected section using mismatching refinement with domain decomposition
Authors: Park K. , Yang D.Y. , Kang Y.S.
Published: July 2002

The present work is concerned with three‐dimensional finite element analysis of the hollow section extrusion process using a porthole die. The effects of related design parameters are discussed through the finite element simulation for extrusion of a triply‐connected rectangular tubular section. For economic computation, mismatching refinement, an efficient domain decomposition method with different mesh density for each subdomain is implemented. In order to obtain the uniform flow at the outlet, design parameters such as the hole size and the hole position are investigated and compared through the numerical analysis. Comparing the velocity distribution with that of the original design, it is concluded that the design modification enables more uniform flow characteristics. The analysis results are then successfully reflected on the industrial porthole die design.
Training Needs Assessment Data‐gathering Methods:
Authors: McClelland Samuel B.
Published: July 2002

The fourth in a series of four articles which explores training needs
assessment (TNA) data‐gathering methods: survey questionnaires,
individual interviews, focus groups, and on‐site observations.
Originally presented in a condensed format in an article entitled
“Training Needs Assessment: An ‘Open‐systems’ Application” and published in
the Journal of European Industrial Training, Vol. 17 No. 1, this article
presents the method of using on‐site observations as a means of
gathering relevant training needs data. Emphasis is placed on using
observations in both production as well as non‐production or
administrative environments. Alternatively, presents and discusses the
selection and use of subject matter experts (SMEs). Explores the
advantages and disadvantages of using internal and external SMEs:
stresses analysis of data and recommends that only individuals who are
qualified, trained and/or experienced in observations should conduct
them. Concludes that a more balanced approach for conducting on‐site
observations is in using a combination of both internal as well as
external SMEs.
Training and development in the UK context: an emerging polarisation?
Authors: Tregaskis Olga , Brewster Chris
Published: July 2002

This paper aims to highlight the main debates in the field of skill development in a UK context. We begin with an examination of the economic and labour market conditions and their potential implications for skill development. The supply of training and development is examined through a critique of policy developments in both initial and continuing education and training. Original survey data are used in combination with national statistical sources and other survey findings to present a picture of human resource development activity within organisations. In conclusion the paper considers the implications of national policy and economic and labour market conditions for the state, employers and the individual.
Asymptotic approximations for the distributions of the (h‐, φ‐)‐divergence goodness‐of‐fit statistics: application to Renyi’s statistic
Authors: Menéndez M.L. , Pardo J.A. , Pardo L. , Pardo M.C.
Published: July 2002

Read (1984) presented an asymptotic expansion for the distribution function of the power divergence statistics whose speed of convergence is dependent on the parameter of the family. Generalizes that result by considering the family of (h, φ)‐divergence measures. Considers two other closer approximations to the exact distribution. Compares these three approximations for the Renyi’s statistic in small samples.
The perceived importance of sales managers’ rewards: a career stage perspective
Authors: Mehta Rajiv , Anderson Rolph E. , Dubinsky Alan J.
Published: July 2002

The primary intent of this research was to determine whether the perceived importance of various rewards is influenced by the career stage of sales managers. This study found that sales managers in different career stages have distinct intrinsic and extrinsic reward preferences that may ultimately affect motivation and productivity. Although several statistically significant differences in intrinsic and extrinsic reward preferences were discerned, some reward perceptions were found to be uniform regardless of sales manager career stage. Sales management implications, limitations, and directions for future research are offered.
A framework for research evaluation in management science
Authors: Lehaney Brian , Clarke Steve
Published: July 2002

A major problem facing students undertaking postgraduate study is
that of taking far greater responsibility for their own independent
learning than was the case at undergraduate level. In managing this
transition, educators must ensure that students are provided with the
necessary tools. In particular, at postgraduate level, a strong emphasis
is placed on research, yet most undergraduate courses will not have
equipped students with any framework for evaluating research. Such a
framework is important in assessing the completed work of other authors,
for evaluating a proposed research programme, and for reviewing work in
progress. Provides a set of guidelines which will enable students to
valuate management science research effectively and efficiently.
A re‐engineering framework for total home‐school partnership
Authors: Ming Tam Wai , Cheong Cheng Yin , Ming Cheung Wing
Published: July 2002

Aims to develop a framework that can provide a total conception of home‐school partnership and can be used to re‐engineer the existing superficial and fragmentary practice of home‐school co‐operation in both Hong Kong and international contexts. Argues that, using this framework to re‐engineer the traditional home‐school relationship and achieve total home‐school partnership, the school, family, education authority, as well as the community should each take on new and differentiated roles and should fulfil the functions and expectations as described in the framework. Addresses how the total home‐school partnership can contribute to the effectiveness of school education according to the seven models of school effectiveness: the goal model, the system‐resource model, the process model, the strategic‐constituencies model, the legitimacy model, the organizational learning model and the ineffectiveness model.
The preparation of beginning principals in Queensland
Authors: Hewitson M.T.
Published: July 2002

Reports on a research project which investigated the preparation of
beginning principals in Queensland primary and secondary government
schools. Thirty‐six principals completed a questionnaire, a return rate
of about 80 per cent. Of these principals, 13 were surveyed early in the
second year of their principalship, and 23 in August of their first
year. Six of the first‐year principals were interviewed in the following
month. Presents an overview of the findings, along with some general
observations on their practical implications and recommendations for
action.
Reforming America’s schools 1980‐2000
Authors: Murphy Joseph , Adams Jacob E.
Published: July 2002

Examines the causes, strategies, and dynamics of excellence era educational reforms in the USA. Assesses economic, social and political environmental pressures to reform American education. Examines major governmental, professional, citizen, and market policies promulgated across three generations of reform: an intensification era of government actions to repair the existing school system, a restructuring era focused on improving educational organization and governance, and a reformation era blending standards and accountability mechanisms with citizen and consumer‐oriented reforms. Scrutinizes political, structural, individual, and social dynamics that explain progress and stasis in American public education.
Service quality in education: a student perspective
Authors: Joseph Mathew , Joseph Beatriz
Published: July 2002

Examines New Zealand business students’ perceptions of service quality in education. Describes a study in which the respondents identified seven determinants of service quality. Unlike prior studies, uses an importance/performance‐based approach to evaluate service quality in education. Identifies some perceptual problems, such as the least important factors being the best performers. Presents the implications for education administrators and makes some suggestions for future research.
Managerial opportunism and the capital structure decisions of property companies
Authors: Ooi Joseph T.L.
Published: July 2002

The focus of this paper is on the problem of managerial opportunism in the corporate governance of UK quoted property companies. Agency conflicts exist between firm managers and owners because of the separation of ownership from management. Consequently, managers pursue activities that enhance their interests rather than that of the shareholders’. The empirical investigation of this paper is divided into two sections. The first part examines the ownership structure of 83 UK quoted property companies between 1989 and 1995, revealing that close to a quarter of the common shares issued by the companies are held by the managers. The gap between ownership and management appears to increase with firm size, risk and growth rate but decrease with corporate performance. In the second section, logit modeling is employed to examine 110 security issues of the companies during the study period. The evidence shows that ownership structure has an influence on the debt‐equity choice of property companies. Consistent with the findings of previous studies, the study also reveals that the capital structure choice is dictated to a large extent by company size, issue size, and condition of the security market. The empirical analysis also suggests that property companies make their financing decisions as though they have a target capital structure in mind.
A model of the replication fork blocking protein Fob1p based on the catalytic core domain of retroviral integrases
Authors: Dlakić Mensur
Published: July 2002

The replication fork blocks are common in both prokaryotes and eukaryotes. In most cases, these blocks are associated with increased levels of mitotic recombination. One of the best‐characterized replication fork blocks in eukaryotes is found in ribosomal DNA (rDNA) repeats of Saccharomyces cerevisiae. It has been shown that the replication fork blocking protein Fob1p regulates the recombination rate and the number of rDNA copies in S. cerevisiae, but the mechanistic aspects of these events are still poorly understood. Sequence profile searches revealed that Fob1p is related to retroviral integrases. Subsequently, the catalytic domain of HIV‐1 integrase was used as a template to build a reliable three‐dimensional model of Fob1p. Structural insights from this study may be useful in explaining Fob1p‐mediated formation of extrachromosomal rDNA circles that accelerate aging in yeast and recombination events that lead to expansion or contraction of rDNA.
Distance dependence and salt sensitivity of pairwise, coulombic interactions in a protein
Authors: Lee Kelly K. , Fitch Carolyn A. , García‐Moreno E. Bertrand
Published: July 2002

Histidine pKa values were measured in charge‐reversal (K78E, K97E, K127E, and K97E/K127E) and charge‐neutralization (E10A, E101A, and R35A) mutants of staphylococcal nuclease (SNase) by 1H‐NMR spectroscopy. Energies of interaction between pairs of charges (ΔGij) were obtained from the shifts in pKa values relative to wild‐type values. The data describe the distance dependence and salt sensitivity of pairwise coulombic interactions. Calculations with a continuum electrostatics method captured the experimental ΔGij when static structures were used and when the protein interior was treated empirically with a dielectric constant of 20. The ΔGij when rij ≤ 10 Å were exaggerated slightly in the calculations. Coulomb's law with a dielectric constant near 80 and a Debye‐Hückel term to account for screening by the ionic strength reproduced the salt sensitivity and distance dependence of ΔGij as well as the structure‐based method. In their interactions with each other, surface charges behave as if immersed in water; the Debye length describes realistically the distance where interactions become negligible at a given ionic strength. On average, charges separated by distances (rij) ≈5 Å interacted with ΔGij ≈ 0.6 kcal/mole in 0.01 M KCl, but ΔGij decayed to ≤0.10 kcal/mole when rij = 20 Å. In 0.10 M KCl, ΔGij ≈ 0.10 kcal/mole when rij = 10 Å. In 1.5 M KCl, only short‐range interactions with rij ≤ 5 Å persisted. Although at physiological ionic strengths the interactions between charges separated by more than 10 Å are extremely weak, in situations where charge imbalance exists many weak interactions can cumulatively produce substantial effects.
The Statistical Properties of the Black–Scholes Option Price
Authors: Ncube Mthuli , Satchell Stephen
Published: July 2002

This paper investigates the statistical properties of the Black–Scholes option price, considered as a random variable. The option is conditioned on the current price and/or the estimated volatility of the underlying security. In both cases, some exact results for the distribution functions of the true option price and the predicted option price are derived. Extensions to puts and American contracts are considered. Numerical results are presented for option prices based on parameters appropriate for the FTSE 100 Index.
A Comparison of Bond Ratings from Moody's S&P and Fitch IBCA
Authors: Jewell Jeff , Livingston Miles
Published: July 2002

Previous research has found that the bond market values the ratings of Moody's and Standard & Poor's. This paper extends earlier research by comparing the ratings of Moody's, Standard and Poor's, and Fitch IBCA. The authors examine a very large database with monthly observations of bonds and bond ratings over a five‐year time period. The analysis focuses on comparing rating levels, rating changes, and the impact of ratings on bond yields. The results show that firms with publicly available Fitch IBCA ratings have higher ratings from Moody's and S&P than firms without Fitch IBCA ratings. The typical firm releasing a Fitch IBCA rating has a lower yield (controlling for Moody's and S&P rating), a more stable rating, and is more likely to receive an upgrade. For split‐rated bonds (Moody's vs. S&P), Fitch IBCA serves as a tiebreaker. This evidence is consistent with the bond market valuing the ratings of all three raters—Moody's, Standard & Poor's, and Fitch IBCA.
Effect of nitric oxide donors and noradrenaline on Ca2+ release sites and global intracellular Ca2+ in myocytes from guinea‐pig small mesenteric arteries
Authors: Pucovský Vladimír , Gordienko Dmitri V. , Bolton Thomas B.
Published: July 2002

In smooth muscle the spontaneous Ca2+ release from the sarcoplasmic reticulum (SR) occurs at preferred locations called frequent discharge sites (FDSs) giving rise to localized intracellular Ca2+ transients (Ca2+ sparks). Laser scanning confocal microscopy of fluo‐3‐loaded single myocytes freshly isolated from small mesenteric arteries of guinea‐pig was used to investigate the action of nitric oxide (NO) donors and noradrenaline on the position and activity of FDSs and on global intracellular Ca2+ concentration ([Ca2+]i). In 8% of cells ‘microsparks’, Ca2+ release events smaller in duration, spread and amplitude than Ca2+ sparks were observed. The location of the initiation point of Ca2+ sparks observed during line‐scan imaging was found to ‘jitter’ by ± 0.41 μm. However, the general position of an FDS within the cell did not change; most FDSs were close (within 1.2 ± 0.1 μm) to the cell membrane and often multiple FDSs occurred in one confocal plane of the cell. In the resting state, NO donors S‐nitroso‐N‐acetylpenicillamine (SNAP; 50 μm) and sodium nitroprusside (SNP; 100 μm) did not change the general position of FDSs and slightly depressed their activity, but did not affect the global [Ca2+]i significantly. Application of noradrenaline (1–10 μm) increased Ca2+ spark frequency at existing FDS(s) leading to a Ca2+ wave. The increase in FDS activity and in global [Ca2+]i produced by noradrenaline were inhibited by the presence of SNAP or SNP but not by 8‐bromoguanosine cyclic 3′,5′‐monophosphate (8‐Br‐cGMP; 100 μm). In the presence of 1H‐[1,2,4]oxadiazolo[4,3‐a]quinoxalin‐1‐one (ODQ), inhibitor of soluble guanylate cyclase, SNAP and SNP still exerted their effects on the noradrenaline response. These results suggest that SNAP and SNP inhibit the noradrenaline‐evoked rise in global [Ca2+]i by a cGMP‐independent mechanism and that part of this effect is due to inhibition of the activity of FDSs; moreover, only the activity, but not the position, of FDSs is changed by either stimulant or inhibitory substances.
Comparison of the properties of CLCA1 generated currents and ICl(Ca) in murine portal vein smooth muscle cells
Authors: Britton Fiona C. , Ohya Susumu , Horowitz Burton , Greenwood Iain A.
Published: July 2002

Calcium‐activated chloride currents (ICl(Ca)) have been recorded in various smooth muscle cells but, to date, there has been no information as to the molecular nature of the channel underlying this conductance. We have characterised native ICl(Ca) in freshly dispersed smooth muscle cells isolated from murine portal vein using whole‐cell voltage clamp. ICl(Ca) exhibited time‐dependent activation at depolarised potentials and rapid deactivation upon repolarisation. The reversal potential of ICl(Ca) was close to the theoretical equilibrium potential (ECl) and was shifted by replacement of external Cl− by SCN− or isethionate. Dithiothreitol (DTT, 1 mm), a blocker of CLCA1, had no effect on the ICl(Ca) current in myocytes. RT‐PCR demonstrated the expression of mCLCA1 transcripts, but not mCLCA3 transcripts, in various murine smooth muscle cells including portal vein, as well as cardiomyocytes, and the levels of mCLCA1 transcriptional expression were quantified by real time quantitative RT‐PCR. Stable transfection of HEK293 cells with the cDNA encoding mCLCA1 cloned from murine portal vein smooth muscle yielded a current with notable differences in Ca2+ sensitivity, channel kinetics and modulation by DTT from the native ICl(Ca). However, there was some similarity in the pore properties and these data suggest that mCLCA1 alone does not comprise the Cl− channel in portal vein smooth muscle cells.
Experimental Investigation of Dynamic Normal Characteristics of Machined Joint Surfaces
Authors: Fu W. P. , Huang Y. M. , Zhang X. L. , Guo Q.
Published: July 2002

This paper presents an experimental investigation on the normal dynamic characteristics of several machined joint surfaces, i.e., the varying principle of the normal dynamic stiffness and damping with exciting frequency, relative displacement and static pre-load under different joint conditions, including joint materials, mediums, machining methods and surface roughness, etc.. The joint parameters are extracted from experimental data by establishing the theoretical model of the joint surfaces, and the mechanism is analyzed qualitatively. The studied results show that, in the test range of this paper, the stiffness and damping coefficient of the joint surfaces increase with the static pre-load; the stiffness for a dry joint is independent of the exciting frequency, while the damping coefficients for both a dry and an oiled joint decrease with the exciting frequency; little relative displacement has no marked effect on the dynamic characteristics. The amount of influence of exciting frequency and static pressure is related to the joint conditions. [S0739-3717(00)00804-7]
A Systematic Model for the Analysis of Contact, Side Slip and Traction of Toroidal Drives
Authors: Zhang Y. , Zhang X. , Tobler W.
Published: July 2002

This paper presents a systematic model for the design and analysis of toroidal traction drive continuously variable transmissions (CVT). The contacts between the input disk, the roller and the output disk of the traction drive are formulated using the classical Hertzian contact theory. The traction force and side slip force occurring in CVT operation are modelled based on the elasto-hydrodynammic theory and are correlated to the traction drive geometric and kinematic parameters. The model allows for the quantitative analysis of traction drive operation under various torque inputs and over the desired ratio range. [S1050-0472(00)01004-7]
Spatial Discretization of Axially Moving Media Vibration Problems
Authors: Jha Rajesh K. , Parker Robert G.
Published: July 2002

Spatial discretization of axially moving media eigenvalue problems is examined from the perspectives of moving versus stationary system basis functions, configuration space versus state space form discretization, and subcritical versus supercritical speed convergence. The moving string eigenfunctions, which have previously been shown to give excellent discretization convergence under certain conditions, become linearly dependent and cause numerical problems as the number of terms increases. This problem does not occur in a discretization of the state space form of the eigenvalue problem, although convergence is slower, not monotonic, and not necessarily from above. Use of the moving string basis at supercritical speeds yields strikingly poor results with either the configuration or state space discretizations. The stationary system eigenfunctions provide reliable eigenvalue predictions across the range of problems examined. Because they have known exact solutions, the moving string on elastic foundation and the traveling, tensioned beam are used as illustrative examples. Many of the findings, however, apply to more complex moving media problems, including nontrivial equilibria of nonlinear models. [S0739-3717(00)02103-6]
The Probabilistic Solutions to Nonlinear Random Vibrations of Multi-Degree-of-Freedom Systems
Authors: Er G.-K.
Published: July 2002

The probability density function of the responses of nonlinear random vibration of a multi-degree-of-freedom system is formulated in the defined domain as an exponential function of polynomials in state variables. The probability density function is assumed to be governed by Fokker-Planck-Kolmogorov (FPK) equation. Special measure is taken to satisfy the FPK equation in the average sense of integration with the assumed function and quadratic algebraic equations are obtained for determining the unknown probability density function. Two-degree-of-freedom systems are analyzed with the proposed method to validate the method for nonlinear multi-degree-of-freedom systems. The probability density functions obtained with the proposed method are compared with the obtainable exact and simulated ones. Numerical results showed that the probability density function solutions obtained with the presented method are much closer to the exact and simulated solutions even for highly nonlinear systems with both external and parametric excitations. [S0021-8936(00)01602-0]
A Note on the Driving Traction Acting on a Propagating Interface: Adiabatic and Non-Adiabatic Processes of a Continuum
Authors: Abeyaratne R. , Knowles J. K.
Published: July 2002

An expression for the driving traction on an interface is derived for an arbitrary continuum undergoing an arbitrary thermomechanical process which may or may not be adiabatic. [S0021-8936(00)00403-7]
On the Embedded Kinematic Fractionation of Epicyclic Gear Trains
Authors: Liu Chia-Pin , Chen Dar-Zen
Published: July 2002

In this paper, the concept of kinematic fractionation is introduced for epicyclic gear trains (EGTs) which contains structural fractionation as a degenerate case. With the concept of kinematic fractionation, kinematically independent group(s) embedded in an EGT can be identified. A composition list, which depicts the links and the link connection in the associated group, is used to determine the type of fractionation. It is found that most previously enumerated structurally non-fractionated EGTs in the literature are kinematically fractionated. It is shown that a structurally non-fractionated EGT may be kinematically fractionated while a structurally fractionated EGT must be kinematically fractionated. The concept of kinematic fractionation can lead to efficient topological analysis of EGTs with physical comprehension. [S1050-0472(00)01604-4]
Three-Dimensional Modeling of THD Lubrication in Face Seals
Authors: Tournerie B. , Danos J. C. , Fre^ne J.
Published: July 2002

In this study, the seal is supposed to operate in laminar flow, under steady-state conditions and without phase changing in the lubricant film. The model tackles the three-dimensional general case of misaligned faces and wavy rotor face in stable dynamic tracking regime. The general equations of the THD lubrication and the equations of heat transfer through the rings are established. Different types of heat exchange on the external frontiers of the ring are considered. The equations are numerically solved by using the finite difference method in an iterative procedure which ensure the heat transfer conditions on the boundaries of the fluid film and of the solid rings. Complete and approximated solutions are compared and the validity of the approximations is discussed. A parametric study is carried out in the three-dimensional cases corresponding with misaligned, wavy, and notched faces. The results show the influence of the interface geometry, the nature of the lubricant, the fluid flow, the ring materials, and the different heat transfer conditions on the ring surfaces.
Application of Lubrication Theory to Fluid Flow in Grinding: Part II—Influence of Wheel and Workpiece Roughness
Authors: Hryniewicz P. , Szeri A. Z. , Jahanmir S.
Published: July 2002

The objective of this study is to model fluid flow in grinding with nonporous wheels. While Part I focused on the flow in a simplified smooth geometry, in this part the wheel surface roughness is introduced. The applicability of the modified Reynolds equation for laminar flows between rough surfaces is verified experimentally in terms of the developed hydrodynamic pressure, using a resin-bonded diamond grinding wheel. The experiments were performed under the spark-out condition (i.e., with the wheel just touching the workpiece) and in actual grinding. Agreement between theory and experiment is shown for Re<100, but a significant discrepancy (most likely due to turbulence) is observed for 300<Re<1500.
Free Vibration of a Spinning Stepped Timoshenko Beam
Authors: Yu S. D. , Cleghorn W. L.
Published: July 2002

The finite element method is employed in this paper to investigate free-vibration problems of a spinning stepped Timoshenko beam consisting of a series of uniform segments. Each uniform segment is considered a substructure which may be modeled using beam finite elements of uniform cross section. Assembly of global equation of motion of the entire beam is achieved using Lagrange’s multiplier method. The natural frequencies and mode shapes are subsequently reduced with the help of linear transformations to a standard eigenvalue problem for which a set of natural frequencies and mode shapes may be easily obtained. Numerical results for an overhung stepped beam consisting of three uniform segments are obtained and presented as an illustrative example. [S00021-8936(01)00101-5]
Nonlinear Behavior of Trabecular Bone at Small Strains
Authors: Morgan Elise F. , Yeh Oscar C. , Chang Wesley C. , Keaveny Tony M.
Published: July 2002

Study of the behavior of trabecular bone at strains below 0.40 percent is of clinical and biomechanical importance. The goal of this work was to characterize, with respect to anatomic site, loading mode, and apparent density, the subtle concave downward stress–strain nonlinearity that has been observed recently for trabecular bone at these strains. Using protocols designed to minimize end-artifacts, 155 cylindrical cores from human vertebrae, proximal tibiae, proximal femora, and bovine proximal tibiae were mechanically tested to yield at 0.50 percent strain per second in tension or compression. The nonlinearity was quantified by the reduction in tangent modulus at 0.20 percent and 0.40 percent strain as compared to the initial modulus. For the pooled data, the mean±SD percentage reduction in tangent modulus at 0.20 percent strain was 9.07±3.24 percent in compression and 13.8±4.79 percent in tension. At 0.40 percent strain, these values were 23.5±5.71 and 35.7±7.10 percent, respectively. The magnitude of the nonlinearity depended on both anatomic site p<0.001 and loading mode p<0.001, and in tension was positively correlated with density. Calculated values of elastic modulus and yield properties depended on the strain range chosen to define modulus via a linear curve fit p<0.005. Mean percent differences in 0.20 percent offset yield strains were as large as 10.65 percent for some human sites. These results establish that trabecular bone exhibits nonlinearity at low strains, and that this behavior can confound intersite comparisons of mechanical properties. A nonlinear characterization of the small strain behavior of trabecular bone was introduced to characterize the initial stress–strain behavior more thoroughly.
Changes in Residual Stress in Worked Surface Layer of Type 304 Austenitic Stainless Steel Due to Tensile Deformation
Authors: Hayashi Makoto , Enomoto Kunio
Published: July 2002

Changes in the residual stress in a worked surface layer of type 304 austenitic stainless steel due to tensile deformation were measured by the X-ray diffraction residual stress measuring method. The compressive residual stresses introduced by end-mill, end-mill side cutter, and grinder were easily changed into tensile stresses when the plate specimens were subjected to tensile stress greater than the yield stress of the solid solution heat-treated material. The residual stresses after the tensile deformation depend on the initial residual stresses and the degree of preliminary working. The behavior of the residual stress changes can be interpreted if the surface-worked material is regarded as a composite made of solid solution heat-treated material and work-hardened material.
Concurrent Design of Continuous Zero Phase Error Tracking Controller and Sinusoidal Trajectory for Improved Tracking Control
Authors: Park Hyung-Soon , Chang Pyung Hun , Lee Doo Yong
Published: July 2002

A trajectory control strategy for a nonminimum phase system is proposed. A continuous-time version of the Zero Phase Error Tracking Controller (ZPETC), which is a well-known discrete-time feedforward controller, is considered. In the continuous-time case, the overall transfer function consisting of the ZPETC and the closed-loop plant exhibits high-pass filter characteristics. This introduces serious gain errors between the desired and actual output if the desired output is made directly as the ZPETC’s input. This paper proposes the use of a specially designed sinusoidal trajectory to compensate for the gain errors. The sinusoidal trajectory imparts a synergic effect to tracking performance when combined with the continuous ZPETC. Continuous ZPETC with sinusoidal trajectory is evaluated successfully by applying to a nonminimum phase plant, single link flexible arm.
Bi-Objective Optimization Design of Heterogeneous Injection Mold Cooling Systems
Authors: Huang Jinhua , Fadel Georges M.
Published: July 2002

This paper presents a two-step methodology for the bi-objective optimization design of heterogeneous injection mold cooling systems to achieve simultaneously fast and uniform cooling. During the first step, a single fundamental mold material selected from the material database is assumed, optimal cooling channels size, location, and coolant flow rate are obtained through a gradient-based optimization method. Based on the optimal results from the first step, the second step further reduces cooling time and increases temperature distribution uniformity at ejection by finding sensitive areas and distributing both fundamental and secondary materials in these areas through a genetic algorithm. A Finite Element Method with the Jacobi Conjugate Gradient scheme is utilized to perform the cyclic and transient cooling simulation. Two illustrations for the optimal methodology are provided.
Oscillatory Flow and Gas Transport Through a Symmetrical Bifurcation
Authors: Fujioka Hideki , Oka Kotaro , Tanishita Kazuo
Published: July 2002

Axial gas transport due to the interaction between radial mixing and radially nonuniform axial velocities is responsible for gas transport in thick airways during High-frequency oscillatory ventilation (HFO). Because the airways can be characterized by a bifurcating tube network, the secondary flow in the curved portion of a bifurcating tube contributes to cross-stream mixing. In this study the oscillatory flow and concentration fields through a single symmetrical airway bifurcating tube model were numerically analyzed by solving three-dimensional Navier-Stokes and mass concentration equations with the SIMPLER algorithm. The simulation conditions were for a Womersley number, α=9.1 and Reynolds numbers in the parent tube between 200 and 1000, corresponding to Dn2/α4 in the curved portion between 2 and 80, where Dn is Dean number. For comparison with the results from the bifurcating tube, we calculated the velocity and concentration fields for fully developed oscillatory flow through a curved tube with a curvature rate of 1/10, which is identical to the curved portion of the bifurcating tube. For Dn2/α4⩽10 in the curved portion of the bifurcating tube, the flow divider and area changes dominate the axial gas transport, because the effective diffusivity is greater than in either a straight or curved tube, in spite of low secondary velocities. However, for Dn2/α4⩾20, the gas transport characteristics in a bifurcation are similar to a curved tube because of the significant effect of secondary flow.
Effects of Guide-Vane Number in a Three-Dimensional 60-Deg Curved Side-Dump Combustor Inlet
Authors: Liou Tong-Miin , Lee Hsin-Li , Liao Chin-Chun
Published: July 2002

Three-dimensional flowfields in a 60-deg curved combustor inlet duct of rectangular cross-section with and without guide vanes were measured using Laser-Doppler velocimetry for the longitudinal, radial, and spanwise velocity components. The Reynolds number based on the bulk mean velocity and hydraulic diameter was 2.53×104. The main parameters examined were the guide-vane number and Reynolds number. The results show that to completely eliminate flow separation in the curved combustor inlet three guide vanes should be installed. The critical Reynolds number for the absence of the flow separation is found to decrease with increasing product of radius and aspect ratios. In addition, it is found that in most regions the maximum radial mean velocity, difference between radial and spanwise normal stress, and the turbulent kinetic energy decrease with increasing guide-vane number. A rationale for the absence of flow separation in the one-vane case predicted by previous researchers is also provided.
Stability of Beams on Bi-Moduli Elastic Foundation
Authors: Liu Z. H. , Wang L. , Pan L. Z.
Published: July 2002

This paper adopts the newly structured δ function and displacement function. Using two adjacent transition points as two interval terminals while beams buckle makes the interval [xi−1,xi]. According to the Winkler’s beam buckling theory on elastic foundation, we present the energy solutions of beams and then the exact solutions of buckling load of simple supported beams on bi-moduli elastic foundation.
LDV Measurements of the Flow Field in the Nozzle Region of a Confined Double Annular Burner
Authors: Schmitt Francois , Hazarika Birinchi K. , Hirsch Charles
Published: July 2002

A database for the complex turbulent flow of a confined double annular burner in cold conditions is presented here. In the region close to the exit of the annular nozzles LDV measurements at 5515 grid points in the meridional plane were conducted. At each measurement position, validated data for 3000–16,000 particles were recorded, and the mean axial and radial velocities, axial and radial turbulence intensity and Reynolds stresses were computed. The resulting mean flow field is axisymmetric within an uncertainty of 2 percent. The contour plots of turbulent quantities on the fine grid, as well as the streamlines based on the mean flow field, are presented for the flow.
Comparison of Methods to Measure Grinding Temperatures
Authors: Xu Xipeng , Malkin Stephen
Published: July 2002

Experimental measurements of grinding temperatures are used to estimate the energy partition to the workpiece. In the present investigation, three different temperature measuring techniques are compared for estimating the energy partition in grinding. Grinding temperatures were measured in the workpiece subsurface under identical surface grinding conditions using an embedded thermocouple and a two color infrared detector, and on the workpiece surface using a foil/workpiece thermocouple. All three methods gave comparable temperature responses which were consistent with analytical predictions for the same energy partition.
Using the Concept of Information to Optimally Design Experiments With Uncertain Parameters
Authors: Emery A. F.
Published: July 2002

When thermal systems are described by models, it is necessary to know the properties and parameters of the model to ensure accurate results. These properties are usually determined from experiments designed to maximize the precision of the estimated properties. Achieving such high precision requires that all of the other properties be known with certainty. This paper describes a method of design and estimation based upon Fisher’s concept of information that achieves good precision in estimating thermal properties even when the other parameters are known only approximately.
Solving the Kinematics of Planar Mechanisms by Dixon Determinant and a Complex-Plane Formulation
Authors: Wampler Charles W.
Published: July 2002

This paper presents a general method for the analysis of any planar mechanism consisting of rigid links connected by revolute joints. The method combines a complex plane formulation [1] with the Dixon determinant procedure of Nielsen and Roth [2]. The result is simple to derive and implement, so in addition to providing numerical solutions, the approach facilitates analytical explorations. The procedure leads to a generalized eigenvalue problem of minimal size. Both input/output problems and the derivation of tracing curve equations are addressed, as is the extension of the method to treat slider joints.
On Some Issues in Shakedown Analysis
Authors: Maier G.
Published: July 2002

Shakedown analysis, and its more classical special case of limit analysis, basically consists of “direct” (as distinct from time-stepping) methods apt to assess safety factors for variable repeated external actions and procedures which provide upper bounds on history-dependent quantities. The issues reviewed and briefly discussed herein are: some recent engineering-oriented and cost-effective methods resting on Koiter’s kinematic theorem and applied to periodic heterogeneous media; recent extensions (after the earlier ones to dynamics and creep) to another area characterized by time derivatives, namely poroplasticity of fluid-saturated porous media. Links with some classical or more consolidated direct methods are pointed out.
Stress Analysis of Layered Elastic Solids With Cracks Using the Fast Fourier Transform and Conjugate Gradient Techniques
Authors: Polonsky I. A. , Keer L. M.
Published: July 2002

The fast Fourier transform (FFT) technique has recently been applied to stress analyses of layered elastic solids, with a great deal of success. However, the existing FFT-based methods are limited to intact solids. This paper explores the possibility of using FFT for stress analyses of layered elastic solids containing cracks. A new numerical approach is developed by combining three-dimensional FFT with the theory of periodic eigenstrain and the conjugate gradient method. The new method is primarily designed for analyzing complex three-dimensional crack patterns in layered solids, such as those produced in thin protective coatings by roughness-induced contact stresses. The method should be particularly advantageous for studying crack propagation in coatings, as it does not require remeshing when the crack shape changes. Numerical examples illustrating advantages as well as limitations of the method are presented. Some unexpected results that were obtained for multiple cracks in a thin coating are discussed.
Melting and Resolidification of a Substrate Caused by Molten Microdroplet Impact
Authors: Attinger D. , Poulikakos D.
Published: July 2002

This paper describes the main features and results of a numerical investigation of molten microdroplet impact and solidification on a colder flat substrate of the same material that melts due to the energy input from the impacting molten material. The numerical model is based on the axisymmetric Lagrangian Finite-Element formulation of the Navier–Stokes, energy and material transport equations. The model accounts for a host of complex thermofluidic phenomena, exemplified by surface tension effects and heat transfer with solidification in a severely deforming domain. The dependence of the molten volume on time is determined and discussed. The influence of the thermal and hydrodynamic initial conditions on the amount of substrate melting is discussed for a range of superheat, Biot number, and impact velocity. Multidimensional and convective heat transfer effects, as well as material mixing between the droplet and the substrate are found and quantified and the underlying physics is discussed. Good agreement in the main features of the maximum melting depth boundary between the present numerical results and published experiments of other investigators for larger (mm-size) droplets was obtained, and a complex mechanism was identified, showing the influence of the droplet fluid dynamics on the substrate melting and re-solidification.
TEHD Behavior of Non-Newtonian Dynamically Loaded Journal Bearings in Mixed Lubrication for Direct Problem
Authors: Zhang Chao
Published: July 2002

A transient non-Newtonian TEHD analysis for dynamically loaded journal bearings in mixed lubrication is developed for direct problem. A mass conserving cavitation is included and viscoelasticity subsuming shear thinning is characterized by the upper converted Maxwell fluid and the power law fluid models. The Reynolds equation, the transient two-dimensional energy equation in the film, the quasi-steady-state two-dimensional heat conduction equation in the bushing and heat balance in the journal are solved using finite difference formulations. The thermal and elastic deformation equations are solved using the finite element method. The relation between the average contact pressure and the average gap is numerically determined in micro scale. Effects of roughness texture, degree of asperity contact, shear index, relaxation time, thermal and elastic deformations on bearing behavior are investigated.
Film-Cooled Turbine Endwall in a Transonic Flow Field: Part II—Heat Transfer and Film-Cooling Effectiveness
Authors: Nicklas Martin
Published: July 2002

Thermodynamic and aerodynamic measurements were carried out in a linear turbine cascade with transonic flow field. Heat transfer and adiabatic film-cooling effectiveness resulting from the interaction of the flow field and the ejected coolant at the endwall were measured and will be discussed in two parts. The investigations were performed in the Windtunnel for Straight Cascades (EGG) at the DLR, Goettingen. The film-cooled NGV endwall was operated at representative dimensionless engine conditions of Mach and Reynolds number Ma2is=1.0 and Re2=850,000 respectively. Part II of the paper discusses the thermodynamic measurements. Detailed temperature measurements were carried out on a turbine stator endwall. In order to determine the surface heat transfer and adiabatic film-cooling effectiveness, an infrared camera system in a rectilinear wind tunnel measured the endwall temperatures in the transonic flow field. The adiabatic film-cooling effectiveness was determined using the superposition method. Measurements were carried out to first, validate the assumptions of theory and second, analyze the error associated with the measurements. Effects of coolant ejection from a slot and three rows of holes were investigated and compared with each other. The influence of Mach number and blowing ratio on the heat transfer were further aspects of the investigation. Strong variations in heat transfer and film-cooling effectiveness due to the interaction of the coolant air and the secondary flow field were found. Based on the results of this investigation an improved cooling design will be investigated in a follow-up project.
Development of Zero-Spin Planetary Traction Drive Transmission: Part 1 — Design and Principles of Performance Calculation
Authors: Ai Xiaolan
Published: July 2002

A novel design of planetary tapered roller traction drive was described. The design eliminated the spin motion induced sliding, offering high mechanical efficiency and improved wear performance. Principles of performance calculation have been outlined. Torque and life calculations on a 186 kw (250 hp) prototype indicated a remarkable torque capacity and satisfactory durability.
On the Optimal Shape of a Rotating Rod
Authors: Atanackovic T. M.
Published: July 2002

By using Pontryagin’s maximum principle we determine the shape of the lightest rotating rod, stable against buckling. It is shown that the cross-sectional area function is determined from the solution of a nonlinear boundary value problem. Three variational principles for this boundary value problem are formulated and a first integral is constructed. The optimal shape of a rod is determined by numerical integration.