bluuebunny/crossref_metadata_2025 huggingface dataset:
Elicit, engage, experience, explore: discovery learning in library instruction
Authors: Bicknell‐Holmes Tracy , Seth Hoffman Paul
Published: July 2002

Discovery learning is a teaching strategy instructors can utilize to increase the engagement of and content relevance to students involved in library instruction. There are five learning “architectures” which discovery learning comprises: Case‐based learning; Incidental learning; Learning by exploring; Learning by reflection; and Simulation‐based learning. Alone, or in combination, they can be applied to activities and the teaching of skills across the spectrum of complexity, curricular format, and class size. These architectures are not intended to supplant established and more traditional methods of instruction; rather, they serve to enhance the effectiveness and the likelihood of mastery and application of skills and concepts. Though perceptual and attitudinal barriers can create obstacles to implementing discovery learning, these can be overcome. The authors recommend a gradual application of discovery learning activities to instruction.
Robots in agriculture
Authors: Hollingum Jack
Published: July 2002

SILVER, the special interest group on advanced robotics and intelligent automation, is holding a series of meetings on applications in different sectors of industry. The May meeting was held at the Silsoe Research Institute in Bedfordshire. Speakers from Silsoe, as well as from universities and industry, reviewed a number of applications, current and potential, and some systems were demonstrated during the lunch break.
An analysis of the utilization and effectiveness of non‐financial incentives in small business
Authors: Appelbaum Steven H. , Kamal Rammie
Published: July 2002

This research was conducted in order to determine what variables would give small businesses (defined as any firm with less than 100 employees) an advantage versus larger businesses in attracting and maintaining employees while optimizing their performance. Job enrichment, employee recognition, pay equity and managerial skill do affect employee job satisfaction in small business. However, there was sufficient evidence to indicate that income was, at the very least, a moderating factor with regard to the success of non‐monetary incentives. Therefore, the variables studied are most effective when supplemented with an income that allows employees to meet physiological and security needs for themselves and their families. What this article demonstrates is that by increasing job satisfaction via job enrichment, employee recognition, internal pay equity and the use of skilled managers, smaller firms can increase productivity and attractiveness to existing and potential employees.
Effectiveness of ISO 9000 in raising construction quality standards: some empirical evidence using CONQUAS scores
Authors: Sui Pheng Low , Boon Kee Tan , Ang Aik Leng Allen
Published: July 2002

To enhance and promote quality construction, the Construction Quality Assessment System (CONQUAS) was introduced in Singapore in 1989 to evaluate the quality performance of building contractors using numerical scores. Apart from the CONQUAS system, the ISO 9000 quality management standards were also introduced in the Singapore construction industry in 1991. Is there a relationship between certification to ISO 9000 standards and the achievement of higher construction quality standards as indicated by CONQUAS scores? As several years have passed since the introduction of the CONQUAS system and ISO 9000 in the Singapore construction industry, this paper aims to ascertain if the implementation and certification of quality management systems to ISO 9000 standards in construction firms has helped them to achieve higher construction quality standards through higher CONQUAS scores.
The IT effects on competitiveness for interaction between manufacturing and marketing: six Taiwan cases
Authors: Hsu Li‐Ling
Published: July 2002

This study is to explore the impact of information technology (IT) on the interaction between manufacturing and marketing. Literature reviews are initially conducted to understand the interfunctional goal gap and activity conflict that exist between the two departments which invariably constitute achievement on corporate competitiveness. The application dimension of IT function is introduced as a useful tool in reducing the degree of interfunctional gap through advanced IT which in turn will reduce the conflict on the activity level. Thus, the ultimate end might lead to positive effects on corporate competitiveness. In this paper, we discuss the interaction of manufacturing and marketing departments and the resulting capacity of IT in six firms, located in the HsinChu Science‐Based Industrial Park (HSIP) in Taiwan. HSIP is referred to as Taiwan’s Silicon Valley. This study’s methodology is based on a case study. Deep analysis of the six cases leads to ten hypotheses.
Recent developments in the incremental flow formulation for the numerical simulation of metal forming processes
Authors: Bonet Javier
Published: July 2002

This paper describes the use of the incremental flow formulation for the numerical analysis of forming processes. This formulation is based on the approximation of the flow type of constitutive equations by means of an algorithmic equation based on geometry changes over a timestep. The resulting equilibrium equations are functions of nodal positions. Hence geometrical constraints such as contact and incompressibility can be enforced in an exact manner. Two types of incremental equations leading to first and second order time approximations are presented. The more accurate case is based on the incremental logarithmic stretches. Several examples will be used to demonstrate the validity of the method.
An understanding of the structure and geography of the subcontract PCB industry in the UK
Authors: Hughes Cy , Williams David J. , Edwards Terry
Published: July 2002

This paper examines the make‐up of the subcontract printed circuit board industry in the UK and identifies the geographical location of manufacturing sites together with the number of employees at these sites. It describes both the subcontract board‐producing and assembly sectors. The maps show the position and size of the sites, and these together with a histogram showing the frequency of ranges of employee numbers, provide an understanding of the structure of the industry. Higher density areas which have a greater incidence of PCB manufacturing activity are identified and compared. It is also shown that there is little consistent relationship between the positions of the major system providers and the PCB subcontract industry sites. Concern is expressed about the ability of the many smaller companies to compete in the supply of emerging assembly and substrate technologies.
Management training in UK NGOs: a small survey
Authors: Amos‐Wilson Pauline
Published: July 2002

A survey of 21 UK NGOs identified a number of interesting issues associated with management training activities within them. These issues include a dissatisfaction with management training, the mis‐match between stated organizational training needs and what training was in fact engaged in, the apparent lack both of a systematic approach to management training, or of learning from approaches to training in other sectors, and the role of evaluation. These findings lead to the observation that perhaps the purpose of management training within NGOs needs to be assessed within the framework of the donating public’s image of the sector.
Piperylene‐styrene copolymer for adhesive applications
Authors: Jankauskaite V. , Barkauskas R.
Published: July 2002

Discusses the use of piperylene‐styrene copolymer (PSC) for polychloroprene adhesive modification. States that PSC significantly improves modified adhesive properties ‐ bond strength, viscosity, high heat resistance, good adhesion to a variety of substrates, compatibility with other adhesive additives. Looks at the advantage of using more environmentally friendly technology for thermoplastic rubber bonding with PSC modified polychloroprene adhesives. Concludes that the new adhesive product can be used for specific combinations of materials and application methods, making it possible to produce cheaper and better products.
Leadership for teachers’ action learning
Authors: Yiu Yuen Pong , Cheong Cheng Yin
Published: July 2002

Action learning can help teachers gain the necessary professional competence for making better judgements and taking effective action in ambiguous situations. It thus enhances teachers’ professional practice and performance in a changing and uncertain environment. This paper intends to propose a leadership framework for facilitating teachers’ action learning in school. This framework may not only bridge the theoretical gap between school leadership and teachers’ action learning but also enrich the knowledge base of school leadership. The framework comprises three dimensions – inspiring, social supporting, and enabling – and eight components. The inspiring dimension is composed of three components: building and institutionalizing shared vision, providing individualized job design, and modeling. The social supporting dimension encompasses another three components: reducing defensive routines, fostering learning culture, and mobilizing social support. The enabling dimension comprises two components: enhancing theoretical knowledge and repertoires of skills, and providing intellectual stimulation. A principal who exercises this framework has high potential to facilitate teachers’ action learning in school. A list of expected teachers’ cognitive/behavioral characteristics is incorporated in the framework as indicators for the occurrence of teachers’ action learning. Some implications of this framework for research and theory development, and particularly the knowledge base of school leadership, will be discussed at the end of this paper.
Partnership in social work education: a Northern Irish experience
Authors: Bamford David R.
Published: July 2002

Analyses the experience of partnership in social work education between the University of Ulster and external social work organizations between 1990‐1995. Using a historical perspective, considers key issues associated with this collaborative process, all of which are of fundamental relevance to managers in education. Draws on the author’s own experience as chairperson of the USSET Partnership for four years, making extensive use of documentary evidence such as minutes and policy statements, and consults widely with key personnel in other organizations within the partnership framework. Affords a glimpse of the troubled socio‐political Northern Irish context within which the partnership functions.
Simulation of fluid flow and gaseous radiation heat transfer in a natural gas‐fired furnace
Authors: Song Ge , Bjørge Tor , Holen Jens , Magnussen Bjørn F.
Published: July 2002

Reports that major advances have been achieved on computational simulations of multidimensional fluid flow, heat and mass transfer during the last 20 years. Focuses on the numerical prediction of fluid flow, combustion and gas radiation in a combustion chamber of a typical industrial glass‐melting furnace. Carries out the flow simulation in a three‐dimensional calculation domain by using computer models in conjunction with the standard k ‐ ε turbulence model. Tests the predictions of spectral intensity by solving the equation of radiative transfer. Employs the Goody statistical narrow band model with the Curtis‐Godson approximation to calculate radiative properties for inhomogeneous gas mixtures.
Internet conferencing with networked virtual environments
Authors: Towell John F. , Towell Elizabeth R.
Published: July 2002

Describes a networked virtual environment, a type of virtual
reality most commonly known as a “MUD” or a
“MOO”, which was used at an internationally‐attended
scientific conference held on the Internet. Interviews with conference
attendees indicated enthusiasm for the effectiveness of the medium, and
revealed how the virtual environment can be modified to improve
conferencing efficacy. Such alterations included: novel input‐output
control management; automation of conference registration; control of
anonymous or guest connections; simplification of conference center
topography; an improved methodology for recording discussion sessions;
use of moderated rooms to compensate for network lag; and providing
buffers to update late arriving participants. Concludes that networked
virtual environments provide an inexpensive means for effective
international conferencing on the Internet.
Investment valuation models
Authors: French Nick , Cooper Richard
Published: July 2002

It is well recognised that the UK commercial property market has traditionally used nominal market benchmarks such as the all‐risk yield based on the assumption that rents are received annually in arrears. Obviously, the reality of the market is that rents are invariably received quarterly in advance and it has been suggested that valuers should move towards valuation techniques that reflect the actual timing of the cash flow. The Investment Property Forum issued a paper in September 1999 promulgating the use of quarterly in advance valuations. Parry’s Tables provides quarterly in advance formulae that reflect the reality of rental income and indicates that an annual effective yield should be used instead of a nominal yield to compensate for the subsequent compounding resulting from an income received quarterly. However, as will be shown, the effective yield formula provided by Parry’s does not reflect quarterly payments that are received in advance so compromising the accurate transition from annually in arrears to quarterly in advance formulae based valuations. Tables produced by the IPF have rectified this problem in part as they correctly work on the premise that capital values will not change as the profession changes to a quarterly approach. It is the yield which will be expressed differently. The use of an all risk yield technique for valuation is actually a comparative method. The way in which the yield is expressed is not the critical issue, it is the multiplier against the rent which will determine value. This paper provides the formula required to accurately transfer annually in arrears data into quarterly in advance data together with the formulae required for contemporary growth explicit discounted cash flows (DCF).
Stability and interactions of the amino‐terminal domain of ClpB from Escherichia coli
Authors: Tek Vekalet , Zolkiewski Michal
Published: July 2002

ClpB is a member of a multichaperone system in Escherichia coli (with DnaK, DnaJ, and GrpE) that reactivates aggregated proteins. The sequence of ClpB contains two ATP‐binding regions that are enclosed between the N‐ and C‐terminal extensions. Whereas it has been found that the N‐terminal region of ClpB is essential for the chaperone activity, the structure of this region is not known, and its biochemical properties have not been studied. We expressed and purified the N‐terminal fragment of ClpB (residues 1–147). Circular dichroism of the isolated N‐terminal region showed a high content of α‐helical structure. Differential scanning calorimetry showed that the N‐terminal region of ClpB is thermodynamically stable and contains a single folding domain. The N‐terminal domain is monomeric, as determined by gel‐filtration chromatography, and the elution profile of the N‐terminal domain does not change in the presence of the N‐terminally truncated ClpB (ClpBΔN). This indicates that the N‐terminal domain does not form strong contacts with ClpBΔN. Consistently, addition of the separated N‐terminal domain does not reverse an inhibition of ATPase activity of ClpBΔN in the presence of casein. As shown by ELISA measurements, full‐length ClpB and ClpBΔN bind protein substrates (casein, inactivated luciferase) with similar affinity. We also found that the isolated N‐terminal domain of ClpB interacts with heat‐inactivated luciferase. Taken together, our results indicate that the N‐terminal fragment of ClpB forms a distinct domain that is not strongly associated with the ClpB core and is not required for ClpB interactions with other proteins, but may be involved in recognition of protein substrates.
Thermosensitivity of muscle: high‐intensity thermal stimulation of muscle tissue induces muscle pain in humans
Authors: Graven‐Nielsen T. , Arendt‐Nielsen L. , Mense S.
Published: July 2002

Small‐calibre afferent units responding to thermal stimuli have previously been reported to exist in muscle. The question as to whether these receptors in humans mediate subjective thermal sensations from muscle remains unresolved. The aims of the present study were to determine in humans whether intramuscular injection of warm and cold isotonic saline elicits temperature sensations, muscle pain or any other sensations. In 15 subjects, no thermal sensations assessed on a temperature visual analogue scale (VAS) could be detected with intramuscular injections of isotonic saline (1.5 ml) into the anterior tibial muscle at temperatures ranging from 8 to 48 °C. The same subjects recorded strongly increasing scores on a temperature VAS when thermal stimuli in the same intensity range were applied to the skin overlying the muscle by a contact thermode. However, i.m. isotonic saline of 48 °C induced muscle pain with peak scores of 3.2 ± 0.8 cm on a VAS scale ranging from 0 to 10 cm. Using the the McGill pain questionnaire a subgroup, of subjects qualitatively described the pain using the ‘thermal hot’ and ‘dullness’ word groups. Temperature measurements within the muscle during the stimulating injections showed that the time course of the pain sensation elicited by saline at 48 °C paralleled that of the intramuscular temperature and far outlasted the injection time. The present data show that high‐intensity thermal stimulation of muscle is associated with muscle pain. High‐threshold warm‐sensitive receptors may mediate the pain following activation by temperatures of 48 °C or more. Taken together, the data indicate that thermosensation from a given volume of muscle is less potent than nociception.
Vago‐sympathoadrenal reflex in thermogenesis induced by osmotic stimulation of the intestines in the rat
Authors: Osaka Toshimasa , Kobayashi Akiko , Inoue Shuji
Published: July 2002

Duodenal infusion of hypertonic solutions elicits osmolality‐dependent thermogenesis in urethane‐anaesthetized rats. Here we investigated the involvement of the autonomic nervous system, adrenal medulla and brain in the mechanism of this thermogenesis. Bilateral subdiaphragmatic vagotomy greatly attenuated the first hour, but not the later phase, of the thermogenesis induced by 3.6 % NaCl (10 ml kg−1). Neither atropine pretreatment (10 mg kg−1, i.p) nor capsaicin desensitization had any effect on the osmotically induced thermogenesis, suggesting the involvement of non‐nociceptive vagal afferents. Bilateral splanchnic denervation caudal to the suprarenal ganglia also had no effect, suggesting a lack of involvement of spinal afferents and sympathetic efferents to the major upper abdominal organs. Adrenal demedullation greatly attenuated the initial phase, but not the later phase, of thermogenesis. Pretreatment with the β‐blocker propranolol (20 mg kg−1, i.p) attenuated the thermogenesis throughout the 3 h observation period. The plasma adrenaline concentration increased significantly 20 min after osmotic stimulation but returned to the basal level after 60 min. The plasma noradrenaline concentration increased 20 min after osmotic stimulation and remained significantly elevated for 120 min. Therefore, adrenaline largely mediated the initial phase of thermogenesis, and noradrenaline was involved in the entire thermogenic response. Moreover, neither decerebration nor pretreatment with the antipyretic indomethacin (10 mg kg−1, s.c) had any effect. Accordingly, this thermogenesis did not require the forebrain and was different from that associated with fever. These results show the critical involvement of the vagal afferents, hindbrain and sympathoadrenal system in the thermogenesis induced by osmotic stimulation of the intestines.
Chatter Instability in Milling Systems with Flexible Rotating Spindles—A New Theoretical Approach
Authors: Tian Jifang , Hutton Stanley G.
Published: July 2002

The stability characteristics of a milling system are investigated in this paper. A model is developed that includes the gyroscopic effects of the rotating spindle and on the basis of this model new insight into the physics of chatter instability is obtained. In the analysis the basic Fourier series method for solving a harmonically time-varying system without time lag is extended to obtain a finite-order characteristic equation for the milling system in terms of the system matrices. The complex eigenvalues of the resulting characteristic equation can be efficiently predicted by using Mu¨ller’s optimization algorithm with deflation, and the stability lobes can be predicted by using a nonlinear optimization procedure at different rotating speeds based on the Nyquist stability criterion. In this study it was found that including the gyroscopic effects of the rotating spindle increases the real parts of the eigenvalues of the system. This reduces the critical axial depth of cut. It is also found that the milling forces primarily excite the backward-wave modes but stabilize the forward-wave modes of the rotating spindle.
Studies of Spray Breakup and Mixture Stratification in a Gasoline Direct Injection Engine Using KIVA-3V
Authors: Assanis Dennis N. , Hong Sang Jin , Nishimura Akihiro , Papageorgakis George , Vanzieleghem Bruno
Published: July 2002

The Low Pressure spray Breakup (LPB) model of Papageorgakis and Assanis has been implemented in the multi-dimensional code KIVA-3V as an alternative to the standard Taylor Analogy Breakup (TAB) model. Comparison of spray predictions with measurements shows that the LPB model, in conjunction with the standard k-ε turbulence model, has the potential for simulating the evolution of hollow cone sprays with acceptable fidelity, both from qualitative and quantitative standpoints. After validating the LPB model, illustrative studies of mixture stratification are conducted for a Direct Injection Gasoline (DIG) combustion chamber resembling the Mitsubishi design. The effects of reverse tumble strength and injection timing on mixture quality in the vicinity of the spark plug are explored. Overall, the study demonstrates how the KIVA-3V code with the LPB model can contribute to the optimization and control of mixing in DIG engines. [S0742-4795(00)00303-3]
Effects of Air Entrainment on the Ability of Air Vessels in the Pressure Surge Suppressions
Authors: Lee T. S.
Published: July 2002

This paper describes a new and efficient model for the study of air entrainment effects on the responses of a typical horizontal air vessel. The effects of air entrainment on the pressure surges for unsteady flow in a pipeline system were investigated. Studies showed that entrained, entrapped, or released gases in the transient fluid system tend to amplify the first pressure peak, increase surge damping, and produce asymmetric pressure surges with respect to the static head. The pressure surges showed longer periods of down-surge and shorter periods of upsurge. The upsurge was considerably amplified and down-surge was marginally reduced when compared with the gas-free case. With the horizontal air vessel installed, studies showed that the effects of air entrainment on the maximum transient pressure can be considerably reduced with an appropriately configured air vessel. [S0098-2202(00)00203-0]
Effects of Blending MTBE With Unleaded Gasoline on Exhaust Emissions of SI Engine
Authors: Al-Farayedhi Abdulghani A. , Al-Dawood A. M. , Gandhidasan P.
Published: July 2002

The current paper examines the effects of using MTBE as a replacement of lead additives in gasoline on exhaust emissions of a typical SI engine. The MTBE was blended with a base unleaded fuel in three ratios (10, 15, and 20 vol. percent). The emissions of CO, HC, and NOx were measured at a variety of engine operating conditions using an engine dynamometer setup. The results of the MTBE blends were compared to those of the base fuel and of a leaded fuel prepared by adding TEL to the base. With respect to the base fuel, the addition of MTBE decreased the CO emissions, decreased the HC emissions at most operating conditions, but generally increased the NOx emissions. The emissions results for the leaded fuel were comparable to those of the base fuel. [S0195-0738(00)00103-5]
Effects of Backbone and Endgroup on the Decomposition Mechanisms of PFPE Lubricants and Their Tribological Performance at the Head-Disk Interface
Authors: Chen Chao-Yuan , Bogy David B. , Bhatia C. Singh
Published: July 2002

Tribo-chemical studies of the lubricant endgroup effect on the tribology of the head-disk interface were conducted using carbon disks coated with PFPE lubricant. The studies involved drag tests with uncoated and carbon-coated Al2O3-TiC sliders in an ultrahigh-vacuum (UHV) tribochamber. The UHV drag tests show that a good lubricant should have one active OH endgroup and one nonactive endgroup. The active one insures the lubricant is adsorbed very well onto the disk carbon surface, resulting in a lower removal rate of the lubricants during the contact sliding. The nonactive one prevents the catalytic decomposition of the lubricant in the presence of the Al2O3 surface of the uncoated slider. The studies also demonstrate that the catalytic degradation process of ZDOL in the presence of Lewis acid occurs most readily at the acetal units -O-CF2-O within the internal backbones (CF2O and CF2CF2O) instead of the endgroup functionals. Therefore, demnum, without any acetal units, experiences less catalytic degradation with the uncoated Al2O3/TiC sliders as compared to ZDOL.
A Transport Model for the Deterministic Stresses Associated With Turbomachinery Blade Row Interactions
Authors: van de Wall Allan G. , Kadambi Jaikrishnan R. , Adamczyk John J.
Published: July 2002

The unsteady process resulting from the interaction of upstream vortical structures with a downstream blade row in turbomachines can have a significant impact on the machine efficiency. The upstream vortical structures or disturbances are transported by the mean flow of the downstream blade row, redistributing the time-average unsteady kinetic energy (K) associated with the incoming disturbance. A transport model was developed to take this process into account in the computation of time-averaged multistage turbomachinery flows. The model was applied to compressor and turbine geometry. For compressors, the K associated with upstream two-dimensional wakes and three-dimensional tip clearance flows is reduced as a result of their interaction with a downstream blade row. This reduction results from inviscid effects as well as viscous effects and reduces the loss associated with the upstream disturbance. Any disturbance passing through a compressor blade row results in a smaller loss than if the disturbance was mixed-out prior to entering the blade row. For turbines, the K associated with upstream two-dimensional wakes and three-dimensional tip clearance flows are significantly amplified by inviscid effects as a result of the interaction with a downstream turbine blade row. Viscous effects act to reduce the amplification of the K by inviscid effects but result in a substantial loss. Two-dimensional wakes and three-dimensional tip clearance flows passing through a turbine blade row result in a larger loss than if these disturbances were mixed-out prior to entering the blade row. [S0889-504X(00)01804-3]
Improving Startup Behavior of Fluid Couplings Through Modification of Runner Geometry: Part II—Modification of Runner Geometry and Its Effects on the Operation Characteristics
Authors: Huitenga H. , Mitra N. K.
Published: July 2002

In Part I of this paper, we analyzed the turbulent flow structure and the torque transport characteristics of a fluid coupling. The results suggested certain modifications of the geometry which can improve the start-up behavior and reduce at the same time the material costs. In Part II we perform the numerical simulation of the flow in the modified geometry and investigate the influence of the modification on the performance. [S0098-2202(00)02204-5]
Preface: Special ICE Section
Authors: Assanis Dennis N.
Published: July 2002

[S0742-4795(00)01804-4]
A Conewise Linear Elasticity Mixture Model for the Analysis of Tension-Compression Nonlinearity in Articular Cartilage
Authors: Soltz Michael A. , Ateshian Gerard A.
Published: July 2002

A biphasic mixture model is developed that can account for the observed tension-compression nonlinearity of cartilage by employing the continuum-based Conewise Linear Elasticity (CLE) model of Curnier et al. (J. Elasticity, 37, 1–38, 1995) to describe the solid phase of the mixture. In this first investigation, the orthotropic octantwise linear elasticity model was reduced to the more specialized case of cubic symmetry, to reduce the number of elastic constants from twelve to four. Confined and unconfined compression stress-relaxation, and torsional shear testing were performed on each of nine bovine humeral head articular cartilage cylindrical plugs from 6 month old calves. Using the CLE model with cubic symmetry, the aggregate modulus in compression and axial permeability were obtained from confined compression (H−A=0.64±0.22 MPa, kz=3.62±0.97×10−16 m4/Ns˙s,r2=0.95±0.03), the tensile modulus, compressive Poisson ratio, and radial permeability were obtained from unconfined compression (E+Y=12.75±1.56 MPa, v−=0.03±0.01,kr=6.06±2.10×10−16 m4/Ns˙s,r2=0.99±0.00), and the shear modulus was obtained from torsional shear (μ=0.17±0.06 MPa). The model was also employed to predict the interstitial fluid pressure successfully at the center of the cartilage plug in unconfined compression r2=0.98±0.01. The results of this study demonstrate that the integration of the CLE model with the biphasic mixture theory can provide a model of cartilage that can successfully curve-fit three distinct testing configurations while producing material parameters consistent with previous reports in the literature. [S0148-0731(00)00306-X]
Dynamic Behavior of Lung Surfactant
Authors: Morris J. , Ingenito E. P. , Mark L. , Kamm R. D. , Johnson M.
Published: July 2002

We have previously developed an adsorption-limited model to describe the exchange of lung surfactant and its fractions to and from an air–liquid interface in oscillatory surfactometers. Here we extend this model to allow for diffusion in the liquid phase. Use of the model in conjunction with experimental data in the literature shows that diffusion-limited transport is important for characterizing the transient period from the start of oscillations to the achievement of steady-state conditions. Matching previous data shows that upon high levels of film compression, large changes occur in adsorption rate, desorption rate, and diffusion constant, consistent with what one might expect if the subsurface region was greatly enriched in DPPC. Collapse of the surfactant film that occurs during compression leads to a significant elevation of surfactant concentration immediately beneath the interface, consistent with the subsurface depot of surfactant that has been postulated by other investigators. Modeling studies also uncovered a phenomenon of surfactant behavior in which the interfacial tension remains constant at its minimum equilibrium value while the film is compressed, but without collapse of the film. The phenomenon was due to desorption of surfactant from the interface and termed “pseudo-film collapse.” The new model also gave improved agreement with steady-state oscillatory cycling in a pulsating bubble surfactometer.
The Force and Pressure of a Diffuser-Equipped Bluff Body in Ground Effect
Authors: Senior Andrea E. , Zhang Xin
Published: July 2002

The force and pressure behavior of a generic diffuser in ground effect were investigated. The diffuser model is a bluff body with a rear diffuser at 17 deg to the horizontal, and side-plates. Measurements were conducted in a low speed wind tunnel equipped with a moving ground facility. Techniques employed were force balance, pressure taps, and surface flow visualization. The diffuser flow in ground effect was characterized by vortex flow and three-dimensional flow separation. Four types of force behavior were observed: (a) down-force enhancement at high ride heights characterized by an attached symmetric diffuser flow, (b) maximum down-force at moderate ride heights characterized by a symmetric diffuser flow and separation on the diffuser ramp surface, (c) down-force reduction at low ride heights characterized by an asymmetric diffuser flow and flow separation, and (d) low down-force at very low ride heights, also characterized by an asymmetric diffuser flow and flow separation. The down-force reduction near the ground is attributed to flow separation at the diffuser inlet and subsequent loss of suction in the first half of the diffuser.
Reference Trajectory Tracking of Overhead Cranes
Authors: Moustafa Kamal A. F.
Published: July 2002

This paper addresses the automation problem of overhead cranes. A feedback control strategy is proposed so that the crane travel and hoisting or lowering motions are forced to track a given reference trajectory while killing the payload swing angle. Stability analysis is carried out using Lyapunov functions and it is shown that the equilibrium point of the crane system is asymptotically stable.
Large Deformations of a Rotating Solid Cylinder for Non-Gaussian Isotropic, Incompressible Hyperelastic Materials
Authors: Horgan C. O. , Saccomandi G.
Published: July 2002

The purpose of this research is to investigate the steady rotation of a solid cylinder for a class of strain-energy densities that are able to describe hardening phenomena in rubber. It is well known that use of the classic neo-Hookean strain energy gives rise to physically unrealistic response in this problem. In particular, solutions exist only for a sufficiently small angular velocity. As the velocity approaches this limiting value, the analysis predicts that the rotating cylinder collapses to a disk. It is shown here that this nonphysical behavior does not occur when generalized neo-Hookean models, which exhibit hardening at large deformations, are used.
Economic Evaluation of the Industrial Photosynthesis of Rose Oxide via Lamp or Solar Operated Photooxidation of Citronellol
Authors: Monnerie Nathalie , Ortner Ju¨rgen
Published: July 2002

An economic evaluation regarding the industrial photosynthesis of fine chemical rose oxide using solar light is given and compared to conventional lamps as light source. A plant reaching a capacity of 100 t/a was designed containing app. 1,900 m2 of parabolic troughs, 1,500 m2 of flatbed reactors or 32 high-pressure mercury lamps doped with Thallium iodide (TlI) as a photounit. The investment and production costs were compared and graded. We reached the conclusion that solar application is more profitable than the lamp driven one.
The Potential Impact of Utilizing Advanced Engine Technology for a Combat Capable Unmanned Air Vehicle (UAV)
Authors: Bruening G. B. , Snyder J. R. , Fredette R. E.
Published: July 2002

This paper evaluates the potential impact of utilizing advanced engine technology for a limited life, combat capable, unmanned air vehicle (UAV) application. A study was conducted to define payoffs in terms of mission capability and system level life cycle costs (LCC) associated with implementing three different engine development approaches into a combat capable UAV design. The three different approaches considered were: a new, advanced technology engine; an existing (off-the-shelf) engine; and a derivative of an existing engine with limited technology insertion. A detailed vehicle configuration design was developed to conduct this assessment, including a low observable (LO), highly integrated engine/airframe layout for survivability and mission adaptable considerations. The vehicle is designed with multirole mission capability such as suppression of enemy air defense (SEAD), close air support (CAS), and battlefield air interdiction (BAI). A system level performance comparison is assessed with the three different engine approaches, specifically for the SEAD-type mission. For the cost analysis, the multirole mission capability is reflected in the overall assumptions such as in the number of aircraft needed to meet the mission requirements. A system level assessment such as in this study is essential in determining whether the additional costs associated with the development of a new, advanced engine is worth the investment. The results of this study suggest that advanced engine technology insertion can provide significant benefits in terms of mission range capability, vehicle weight/size, and overall life cycle costs versus an existing engine.
On Saint-Venant’s Problem for an Inhomogeneous, Anisotropic Cylinder—Part I: Methodology for Saint-Venant Solutions
Authors: Dong S. B. , Kosmatka J. B. , Lin H. C.
Published: July 2002

In this paper, the first in a series of three, a procedure based on semi-analytical finite elements is presented for constructing Saint-Venant solutions for extension, bending, torsion, and flexure of a prismatic cylinder with inhomogeneous, anisotropic cross-sectional properties. Extension-bending-torsion involve stress fields independent of the axial coordinate and their displacements may be decomposed into two distinct parts which are called the primal field and the cross-sectional warpages herein. The primal field embodies the essence of the kinematic hypotheses of elementary bar and beam theories and that for unrestrained torsion. The cross-sectional warpages are independent of the axial coordinate and they are determined by testing the variationally derived finite element displacement equations of equilibrium with the primal field. For flexure, a restricted three-dimensional stress field is in effect where the stress can vary at most linearly along the axis. Integrating the displacement field based for extension-bending-torsion gives that for the flexure problem. The cross-sectional warpages for flexure are determined by testing the displacement equations of equilibrium with this displacement field. In the next paper, the cross-sectional properties such as the weighted-average centroid, center of twist and shear center are defined based on the Saint-Venant solutions established in the present paper and numerical examples are given. In the third paper, end effects or the quantification of Saint-Venant’s principle for the inhomogeneous, anisotropic cylinder is considered.
Biodiesel Development and Characterization for Use as a Fuel in Compression Ignition Engines
Authors: Agarwal A. K. , Das L. M.
Published: July 2002

Neat vegetable oils pose some problems when subjected to prolonged usage in CI engine. These problems are attributed to high viscosity, low volatility and polyunsaturated character of the neat vegetable oils. These problems are reduced to minimum by subjecting the vegetable oils to the process of transesterification. Various properties of the biodiesel thus developed are evaluated and compared in relation to that of conventional diesel oil. These tests for biodiesel and diesel oil include density, viscosity, flash point, aniline point/cetane number, calorific value, etc. The prepared biodiesel was then subjected to performance and emission tests in order to evaluate its actual performance, when used as a diesel engine fuel. The data generated for various concentrations of biodiesel blends were compared with base line data generated for neat diesel oil. It was found that 20 percent blend of biodiesel gave the best performance amongst all blends. It gave net advantage of 2.5 percent in peak thermal efficiency and there was substantial reduction in smoke opacity values. This blend was chosen for long term endurance test. The engine operating on optimum biodiesel blend showed substantially improved behavior. A series of engine tests provided adequate and relevant information that the biodiesel can be used as an alternative, environment friendly fuel in existing diesel engines without substantial hardware modification.
A Novel Parallel Hybrid Transmission
Authors: Tsai L. W. , Schultz G. , Higuchi N.
Published: July 2002

This paper presents a novel transmission mechanism for use in a parallel hybrid vehicle. A parallel hybrid vehicle typically employs two or more power sources to drive the vehicle. For such a vehicle to function properly, a non-conventional transmission mechanism and a microprocessor-based controller are needed to manage the power flow among the various power sources. The transmission mechanism described in this paper can provide a parallel hybrid with thirteen clutching conditions that can be grouped into five major modes of operation, namely, electric motor mode, power mode, CVT/charging mode, engine mode, and regenerative braking mode. The kinematics, statics, and power flow of each mode of operation are analyzed. A numerical example is used to illustrate the principle of operation. Furthermore, a clutching sequence control logic is developed.
Performance Characteristics of Centrifugal Slurry Pumps
Authors: Gandhi B. K. , Singh S. N. , Seshadri V.
Published: July 2002

The performance of two centrifugal slurry pumps has been reported for three solid materials having different particle size distribution (PSD) in terms of head, capacity, and power characteristics. The results have shown that the values of head and efficiency ratios are not only dependent on solid concentration but are also affected by PSD of the solids and properties of the slurry. The addition of fine particles in the slurry of coarser material leads to reduction in the additional losses that occur in the pumps due to the presence of solids. It is also observed that with the increase in the pump size, the additional losses due to presence of solids reduce.
The Fault-Tolerant Control of Magnetic Bearings With Reduced Controller Outputs
Authors: Na Uhn Joo , Palazzolo Alan
Published: July 2002

The fault-tolerant control scheme utilizes grouping of currents to reduce the required number of controller outputs. Reduced current distribution matrices can be calculated with the constraint conditions of the controller outputs and the necessary condition for linearization. Decoupling chokes are not required for the control scheme with grouped currents since fluxes are isolated in C-cores. By reducing controller outputs and removing decoupling chokes the fault-tolerant control scheme is more efficient and practical in terms of industrial applications.
Automotive Vehicle Engine Mounting Systems: A Survey
Authors: Yu Yunhe , Peelamedu Saravanan M. , Naganathan Nagi G. , Dukkipati Rao V.
Published: July 2002

This study divided into three portions to provide performance requirements; overview and development of various engine mounts; and the optimization of engine mount systems. The first part provides an insight about the ideal engine mount system that should isolate vibration caused by engine disturbance force in various speed range and prevent engine bounce from shock excitation. This implies that the dynamic stiffness and damping of the engine mount should be frequency and amplitude dependent. Therefore, the development of engine mounting systems has mostly concentrated on improvement of frequency and amplitude dependent properties. The second part starts discussion on the conventional elastomeric mounts that offer a trade-off between static deflection and vibration isolation. The next level, passive hydraulic mounts can provide a better performance than elastomeric mounts especially in the low frequency range. Subsequently, semi-active and active techniques are used to improve performance of hydraulic mounts by making them more tunable. The active engine mounting system can be very stiff at low frequency and be tuned to be very soft at the higher frequency range to isolate the vibration. The final part is about the optimization of engine mounting systems. An overview of the current work on this optimization shows some limitations. Further study is needed to consider the nonlinearities and variations in properties of different types of mounting systems.
Vehicle Evaluation of the Performance of Magneto Rheological Dampers for Heavy Truck Suspensions
Authors: Simon David , Ahmadian Mehdi
Published: July 2002

This study is intended to complement many existing analytical studies in the area of semiactive suspensions by providing a field evaluation of semiactive magneto rheological (MR) primary suspensions for heavy trucks. A set of four controllable MR dampers are fabricated and used experimentally to test the effectiveness of a semiactive skyhook suspension on a heavy truck. In order to evaluate the performance of the semiactive suspensions, the performance of the truck equipped with the MR dampers is primarily compared with the performance of the truck equipped with the stock passive dampers. The performance of the semiactive system and the original passive system are compared for two different driving conditions. First, the truck is driven over a speed bump at approximately 8–11 kmh (5–7 mph) in order to establish a comparison between the performance of the MR and stock dampers to transient inputs at the wheels. Second, the truck is driven along a stretch of relatively straight and level highway at a constant speed of 100 kmh (62 mph) in order to compare the performance of the two types of dampers in steady state driving conditions. Acceleration data for both driving conditions are analyzed in both time and frequency domains. The data for the speed bumps indicate that the magneto rheological dampers used (with the skyhook control policy) in this study have a small effect on the vehicle body and wheel dynamics, as compared to the passive stock dampers. The highway driving data shows that magneto rheological dampers and the skyhook control policy are effective in reducing the root mean square (RMS) of the measured acceleration at most measurement points, as compared to the stock dampers.
Rotordynamic Force Prediction of Whirling Centrifugal Impeller Shroud Passages Using Computational Fluid Dynamic Techniques
Authors: Moore J. J. , Palazzolo A. B.
Published: July 2002

The demand for higher efficiencies and performance of modern centrifugal turbomachinery requires improved knowledge of critical design factors in strength of materials, aerodynamics, and rotordynamics. While tremendous strides in finite element stress analysis and computational fluid dynamics (CFD) have addressed the first two areas, the lack of accurate prediction tools for centrifugal impellers typically leaves rotordynamics out of the design loop. While several authors have analyzed the rotordynamic forces arising from shrouded centrifugal impellers, there has been no study to couple the secondary shroud passage with the three-dimensional primary flow model. The strong interaction between these domains makes this approach advantageous. The current study utilizes CFD techniques to analyze the full three-dimensional viscous, primary/secondary flow field in a centrifugal pump impeller to determine rotordynamic forces. Multiple quasi-steady solutions of an eccentric three-dimensional model at different precessional frequency ratios yield the rotordynamic impedance forces. Performing a second-order least-squares analysis generates the skew-symmetric stiffness, damping, and mass matrices. The results show good correlation with experiment for both performance and rotordynamic forces.