bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolation and characterization of polymorphic microsatellite markers from Australia short‐finned eel (Anguilla australis Richardson)
Authors: GONG XIAO‐LING , LI SI‐FA , CAI WAN‐QI , WANG CHENG‐HUI
Published: June 2008

Seventeen microsatellite DNA loci from the Australian short‐finned eel (Anguilla australis Richardson) were isolated and their amplification characteristics were described. The polymerase chain reaction primers were tested on 40 eel individuals. The primers amplified loci with relatively high numbers of alleles, ranging from five to 14 with an average of nine per locus. Mean observed heterozygosity (HO) and expected heterozygosity (HE) were 0.6779 and 0.7374, respectively, indicating that these markers would be useful for population studies. No loci deviated significantly from Hardy–Weinberg equilibrium (P = 0.05) and no evidence was found for genotypic disequilibrium among loci at a 5% significance level.
ldne: a program for estimating effective population size from data on linkage disequilibrium
Authors: WAPLES ROBIN S. , DO CHI
Published: June 2008

ldne is a program with a Visual Basic interface that implements a recently developed bias correction for estimates of effective population size (Ne) based on linkage disequilibrium data. The program reads genotypic data in standard formats and can accommodate an arbitrary number of samples, individuals, loci, and alleles, as well as two mating systems: random and lifetime monogamy. ldne calculates separate estimates using different criteria for excluding rare alleles, which facilitates evaluation of data for highly polymorphic markers such as microsatellites. The program also introduces a jackknife method for obtaining confidence intervals that appears to perform better than parametric methods currently in use.
Isolation and characterization of new microsatellite markers in shea tree (Vitellaria paradoxa C. F. Gaertn)
Authors: ALLAL FRANÇOIS , VAILLANT ALEXANDRE , SANOU HABY , KELLY BOKARY , BOUVET JEAN‐MARC
Published: June 2008

Vitellaria paradoxa is one of the major components of African parkland agroforestry systems. In order to assess the genetic diversity and population structure of this species, we isolated and characterized 14 polymorphic nuclear microsatellite loci. Primers developed to amplify these loci were used to analyse 200 individuals of a shea tree population in Mali. Loci have shown a high number of alleles ranging from four to 26, and display an observed level of heterozygosity between 0.37 and 0.85. These new very polymorphic microsatellite markers will be useful for genetic and ecological studies of V. paradoxa.
Development of 17 microsatellite markers for Ceratosolen constrictus, the pollinating fig wasp of Ficus fistulosa
Authors: KATABUCHI M. , ISAGI Y. , NAKASHIZUKA T.
Published: June 2008

The obligate mutualism between figs (Ficus) and fig pollinating wasps (Agaonidae) is regarded as a classic example of mutualism. Seventeen polymorphic microsatellite loci were developed for Ceratosolen constrictus, the pollinating wasp of the dioecious fig Ficus fistulosa. The number of alleles per locus ranged from two to 15 and the observed and expected heterozygosities ranged from 0.040 to 0.846 and from 0.040 to 0.916, respectively. These microsatellite loci offer a powerful tool for evolutionary and population genetic studies in C. constrictus, and gene flow of F. fistulosa.
Isolation and characterization of microsatellite loci in the long‐fingered bat Miniopterus fuliginosus
Authors: HAN B. Y. , HUA P. Y. , GU X. M. , MILLER‐BUTTERWORTH C. M. , ZHANG S. Y.
Published: June 2008

We isolated and characterized 10 microsatellite loci in the long‐fingered bat Miniopterus fuliginosus. These loci were tested on 48 individuals from Anhui Province of China, and all loci were highly polymorphic. The mean number of observed alleles per locus was 13.6 (range from six to 27). Observed and expected heterozygosity values ranged from 0.364 to 0.957, and from 0.676 to 0.951, respectively. After Bonferroni correction, four loci deviated significantly from Hardy–Weinberg equilibrium. No pairs of loci were in linkage disequilibrium. These polymorphic markers will be used to examine population structure and genetic diversity in this species.
Characterization of nine polymorphic microsatellite markers in sprat (Sprattus sprattus L.)
Authors: DAILIANIS T. , LIMBORG M. , HANEL R. , BEKKEVOLD D. , LAGNEL J. , MAGOULAS A. , TSIGENOPOULOS C. S.
Published: June 2008

Nine polymorphic microsatellites were isolated from sprat (Sprattus sprattus) using a microsatellite enrichment protocol and selective hybridization with a biotinylated (AC)12 probe. The loci showed different variation patterns in a Baltic Sea population (44 individuals) with mean number of alleles at 12.7 and mean observed heterozygosity at 0.78. These microsatellite loci are expected to be used for taxonomic considerations in sprat, stock differentiation and population genetic analysis.
Isolation and characterization of polymorphic microsatellite loci in yellowtail catfish, Pangasius pangasius (Hamilton, 1822)
Authors: MOHINDRA VINDHYA , SINGH RAJEEV K. , PUNIA PEYUSH , GUPTA HARI SHANKAR , LAL KULDEEP K. , MISHRA AKHILESH , KUMAR RAJESH , SHAH RAMASHANKAR , LAKRA W. S.
Published: June 2008

A total of nine polymorphic microsatellite loci were obtained from a genomic library of Pangasius pangasius (order Siluriformes, family Pangasiidae). Samples from rivers Bhagirathi (n = 22) and Mahanadi (n = 20) were genotyped for each of the nine microsatellite loci to determine genetic variation. The mean number of alleles per locus was 5.22 in Bhagirathi and 5.78 in Mahanadi; and expected heterozygosity ranged from 0.567 (Bhagirathi) to 0.578 (Bhagirathi). Significant deviation (P < 0.003) from Hardy–Weinberg expectations was evident at three loci, Ppa2 (Bhagirathi), Ppa14 (Mahanadi) and Ppa28 (Bhagirathi and Mahanadi). The identified microsatellite loci were found to be promising for population genetics studies of P. pangasius.
Pigmentation effects of solar‐simulated radiation as compared with UVA and UVB radiation
Authors: Wolber Rainer , Schlenz Kathrin , Wakamatsu Kazumasa , Smuda Christoph , Nakanishi Yukiko , Hearing Vincent J. , Ito Shosuke
Published: June 2008

Different wavelengths of ultraviolet (UV) radiation elicit different responses in the skin. UVA induces immediate tanning and persistent pigment darkening through oxidation of pre‐existing melanin or melanogenic precursors, while UVB induces delayed tanning which takes several days or longer to develop and requires activation of melanocytes. We compared the effects of a 2‐week repetitive exposure of human skin to solar‐simulated radiation (SSR), UVA or UVB at doses eliciting comparable levels of visible tanning and measured levels of melanins and melanin‐related metabolites. Levels of eumelanin and pheomelanin were significantly higher in the order of SSR, UVB, UVA or unexposed control skin. Levels of free 5‐S‐cysteinyldopa (5SCD) were elevated about 4‐fold in SSR‐ or UVB‐exposed skin compared with UVA‐exposed or control skin. Levels of protein‐bound form of 5SCD tended to be higher in SSR‐ or UVB‐exposed skin than in UVA‐exposed or control skin. Total levels of 5‐hydroxy‐6‐methoxyindole‐2‐carboxylic acid (5H6MI2C) and 6H5MI2C were higher in SSR‐ than in UVB‐exposed or control skin. These results show that SSR is more effective in promoting delayed tanning than UVB radiation alone, suggesting a synergistic effect of UVA radiation. Furthermore, free 5SCD may serve as a good marker of the effect of SSR and UVB.
The relationship between Rarebit perimetry and OCT‐derived retinal nerve fibre layer thickness in glaucoma
Authors: Katsanos Andreas , Labiris Georgios , Fanariotis Michael , Tsirouki Theodora , Chatzoulis Dimitrios
Published: June 2008

Purpose:  To examine the association between measures of neuroretinal matrix integrity as determined with Rarebit perimetry and optical coherence tomography (OCT)‐derived retinal nerve fibre layer thickness.

Methods:  One randomly selected eye of 30 White primary open‐angle glaucoma patients (age: 60.9 ± 11.7 years; MD: −3.2 ± 5.1 dB) and 16 healthy White individuals (age: 33.2 ± 6.4 years; MD: −0.8 ± 0.8 dB) were included in the study. Participants underwent Rarebit perimetry testing (central field, software version 4) and an OCT fast retinal nerve fibre layer (RNFL) scan. Correlation was investigated between hemifield Rarebit scores and the corresponding RNFL values, as well as between global Rarebit scores and the respective RNFL measures.

Results:  Statistically significant correlations of average hit rate (HR) < 90 and mean hit rate (MHR) were detected with Max–Min and average thickness (Pearson’s r ranging from 0.393 to 0.474). Number HR < 90 showed a moderate correlation only with Max–Min (r = −0.396, P = 0.030). Regarding the association between hemifield hit rates and the corresponding OCT thickness parameters, only inferior maximum correlated moderately with HR superior (r = 0.385, P = 0.035). A tendency was detected for the relationship of superior maximum with HR inferior (r = 0.345, P = 0.062). For the control group, no significant correlation was found for any of the global or hemifield indices and the corresponding thickness values.

Conclusion:  Although Rarebit perimetry is based on a physiological principle distinctly different from conventional perimetry, it provides global indicators of neuroretinal matrix integrity that correlate with some OCT‐derived RNFL thickness measures.
The physiological basis of the effects of intermittent theta burst stimulation of the human motor cortex
Authors: Di Lazzaro V. , Pilato F. , Dileone M. , Profice P. , Oliviero A. , Mazzone P. , Insola A. , Ranieri F. , Meglio M. , Tonali P. A. , Rothwell J. C.
Published: June 2008

Theta burst stimulation (TBS) is a form of repetitive transcranial magnetic stimulation (TMS). When applied to motor cortex it leads to after‐effects on corticospinal and corticocortical excitability that may reflect LTP/LTD‐like synaptic effects. An inhibitory form of TBS (continuous, cTBS) suppresses MEPs, and spinal epidural recordings show this is due to suppression of the I1 volley evoked by TMS. Here we investigate whether the excitatory form of TBS (intermittent, iTBS) affects the same I‐wave circuitry. We recorded corticospinal volleys evoked by single pulse TMS of the motor cortex before and after iTBS in three conscious patients who had an electrode implanted in the cervical epidural space for the control of pain. As in healthy subjects, iTBS increased MEPs, and this was accompanied by a significant increase in the amplitude of later I‐waves, but not the I1 wave. In two of the patients we tested the excitability of the contralateral cortex and found a significant suppression of the late I‐waves. The extent of the changes varied between the three patients, as did their age. To investigate whether age might be a significant contributor to the variability we examined the effect of iTBS on MEPs in 18 healthy subjects. iTBS facilitated MEPs evoked by TMS of the conditioned hemisphere and suppressed MEPs evoked by stimulation of the contralateral hemisphere. There was a slight but non‐significant decline in MEP facilitation with age, suggesting that interindividual variability was more important than age in explaining our data. In a subgroup of 10 subjects we found that iTBS had no effect on the duration of the ipsilateral silent period suggesting that the reduction in contralateral MEPs was not due to an increase in ongoing transcallosal inhibition. In conclusion, iTBS affects the excitability of excitatory synaptic inputs to pyramidal tract neurones that are recruited by a TMS pulse, both in the stimulated hemisphere and in the contralateral hemisphere. However the circuits affected differ from those influenced by the inhibitory, cTBS, protocol. The implication is that cTBS and iTBS may have different therapeutic targets.
On the voltage‐dependent Ca2+block of serotonin 5‐HT3receptors: a critical role of intracellular phosphates
Authors: Noam Yoav , Wadman Wytse J. , Van Hooft Johannes A.
Published: June 2008

Natively expressed serotonin 5‐HT3receptors typically possess a negative‐slope conductance region in theirI–Vcurve, due to a voltage‐dependent block by external Ca2+ions. However, in almost all studies performed with heterologously expressed 5‐HT3receptors, this feature was not observed. Here we show that mere addition of ATP to the pipette solution is sufficient to reliably observe a voltage‐dependent block in homomeric (h5‐HT3A) and heteromeric (h5‐HT3AB) receptors expressed in HEK293 cells. A similar block was observed with a plethora of molecules containing a phosphate moiety, thus excluding a role of phosphorylation. A substitution of three arginines in the intracellular vestibule of 5‐HT3Awith their counterpart residues from the 5‐HT3Bsubunit (RRR‐QDA) was previously shown to dramatically increase single channel conductance. We find this mutant to have a linearI–Vcurve that is unaffected by the presence of ATP, with a fractional Ca2+current (Pf%) that is reduced (1.8 ± 0.2%) compared to that of the homomeric receptor (4.1 ± 0.2%), and similar to that of the heteromeric form (2.0 ± 0.3%). Moreover, whereas ATP decreased the Pf% of the homomeric receptor, this was not observed with the RRR‐QDA mutant. Finally, ATP was found to be critical for voltage‐dependent channel block also in hippocampal interneurons that natively express 5‐HT3receptors. Taken together, our results indicate a novel mechanism by which ATP, and similar molecules, modulate 5‐HT3receptors via interactions with the intracellular vestibule of the receptor.
A Numerical/Experimental Approach to Software Development for Thermoforming Simulations (Survey Paper)
Authors: deLorenzi H. G. , Nied H. F. , Taylor C. A.
Published: June 2008

This paper describes a combined numerical and experimental approach to the development of a software package for simulating the thermoforming process. In this process thin polymer sheets are forced under pressure into a mold cavity. During the forming process the polymer is subjected to large deformations, which result in severe nonuniform thinning. The development of the simulation software was facilitated by a close interaction between numerical modeling and experiment. On the one hand, experimental results guided the development of the software, and on the other hand, numerical developments have been used to suggest new experiments to be performed and critical quantities to be measured. The numerical software is based on the finite element method and the hot polymer is modeled as a nonlinear elastic membrane. Because of the very large deformations occurring in this process, a rigorous large deformation theory has been employed. The numerical formulation also contains contact capabilities for contact between the polymer and the mold and for contact between different parts of the polymer itself. Since very little was known about the physical processes before the program was started, especially about the material behavior and temperatures involved, carefully planned experiments were carried out to guide the selection of the material models used in the software. Since there also was a widespread misconception about the nature of some of the process parameters involved, numerical calculations were used to suggest measurements to be performed on some of these critical parameters. Excellent correlation between calculations and experiment have been obtained and are presented in the paper.
Quantitative Evaluation of Environmentally Assisted Cracking: A Survey of Developments and Application of Modeling Concepts
Authors: Garud Y. S.
Published: June 2008

In recent years there has been a great impetus for the development and application of quantitative methods to correlate and predict the crack initiation and propagation response of materials and structures under the joint action of mechanical loads and the environment. In this paper, after briefing the need and objectives of such methods, some of the current methods—especially, in corrosion fatigue, creep-fatigue, and damage accumulation—and the underlying concepts are critically examined; the main objective of this examination was to identify, and build upon, useful ideas for furthering the state-of-the-art. As a convenient point of reference, the presentation and discussion emphasize the models and concepts, recently developed by the author, for the quantitative evaluation of intergranular stress corrosion cracking (IGSCC); these are based on the premise that the IGSCC damage is related to the imposed strain rate under static as well as dynamic loading situations. In particular, it is concluded that the cumulative (continuum) damage approach currently offers a promising means for evaluating the crack growth response when the concept of effective stress is integrated to account for the loss of load-bearing area (due to the cracking). The significance of these models and concepts is briefly discussed in relation to the plausible mechanistic considerations including film-rupture ideas and the electrochemistry. Also, the logical framework of the modeling is made clear in relation to its engineering application, and subsequent future work is indicated.
Fluidelastic Instability of Heat Exchanger Tube Bundles: Review and Design Recommendations
Authors: Pettigrew M. J. , Taylor C. E.
Published: June 2008

Fluidelastic instability is the most important vibration excitation mechanism for heat exchanger tube bundles subjected to cross-flow. Most of the available data on this topic have been reviewed from the perspective of the designer. Uniform definitions of critical flow velocity for instability, damping, natural frequency and hydrodynamic mass were used. Nearly 300 data points were assembled. We found that only data from experiments where all tubes are free to vibrate are valid from a design point of view. In liquids, fluid damping is important and should be considered in the formulation of fluidelastic instability. From a practical design point of view, we conclude that fluidelastic instability may be expressed simply in terms of dimensionless flow velocity and dimensionless mass-damping. There is no advantage in considering more sophisticated models at this time. Practical design guidelines are discussed.
Fatigue and Creep-Fatigue Life Evaluation of U-Shaped Bellows
Authors: Tsukimori K. , Yamashita T. , Kikuchi M. , Iwata K. , Imazu A.
Published: June 2008

For the reliable operation of bellows under cyclic loadings at high temperatures, a rational evaluation method of life of bellows would be needed. Authors investigated simplified analysis methods for fatigue and creep-fatigue life prediction of U-shaped bellows considering inelasticity as well as various geometrical nonuniformity such as thickness and shape of convolutions. A conservative evaluation method of the strain range is developed, introducing three strain range amplification factors for nominal elastic strain range. Creep and relaxation behaviors of bellows are studied. Consequently, a new evaluation method of creep damage fractions is proposed which depends upon the relation between primary and secondary stresses. Fatigue and creep-fatigue tests are conducted and the validity of the present methods is discussed.
Engineering Treatment Model (ETM) for Crack Driving Force Estimation of Structures With Stress Concentration
Authors: Su H. , Cornec A. , Schwalbe K.-H.
Published: June 2008

A simple relationship for estimating the limit load of a structure with a crack located in a zone with high stress-strain concentration has been suggested using Neuber’s relation. Then, based on the engineering treatment model (ETM), a method for calculating the crack driving force in the structure with a stress concentration was developed. It has also been proved that under deformation plasticity theory and monotonic loading, the ETM can be justified theoretically. Relationships between ETM and other engineering methods have also been established. The predictions by ETM agree well with the test results of full-scale pressure vessels with corner cracks at the joint between cylinder and nozzle.
Fluid Damping and Fluid Stiffness of a Tube Row in Crossflow
Authors: Chen S. S. , Zhu S. , Jendrzejczyk J. A.
Published: June 2008

Motion-dependent fluid forces acting on a tube array were measured as a function of excitation frequency, excitation amplitude, and flow velocity. Fluid-damping and fluid-stiffness coefficients were obtained from measured motion-dependent fluid forces as a function of reduced flow velocity and excitation amplitude. The water channel and test setup provide a sound facility for obtaining key coefficients for fluidelastic instability of tube arrays in crossflow. Once the motion-dependent fluid-force coefficients have been measured, a reliable design guideline, based on the unsteady flow theory, can be developed for fluidelastic instability of tube arrays in crossflow.
Prediction of Transient Vibration Envelopes Using Statistical Energy Analysis Techniques
Authors: Lai M. L. , Soom A.
Published: June 2008

The prediction, by the statistical energy analysis (SEA) method, of transient vibration envelopes for coupled systems is investigated. The relation between the time-varying energy transferred between two coupled subsystems and time-varying energies of the subsystems is studied numerically and experimentally. These studies indicate that time-varying energy transmitted between two subsystems is related to the subsystem energies by an apparent time-varying coupling loss factor. It is shown that the apparent coupling loss factor approaches the asymptotic (or steady-state) coupling loss factor as response energies and transferred energies are integrated over progressively larger times. Both the apparent time-varying coupling loss factor and the asymptotic coupling loss factor, determined experimentally, are used in energy balance equations to predict the time-varying vibration envelopes of a system of two point-coupled plates and the results are compared. Although overall response predictions are similar, considerable differences are noted in individual frequency bands. However, no general method for a priori determination of the apparent time-varying coupling loss factor is suggested.
Collision Detection for Virtual Objects in a Haptic Assembly and Disassembly Simulation Environment
Authors: Coutee Adam S. , Bras Bert
Published: June 2008

There exist a large body of work in the field of assembly, sometimes involving the use of a virtual environment to assist the user in assembly analysis. We have developed HIDRA (Haptic Integrated Dis/Re-assembly Analysis), a real-time haptic simulation for the analysis of assembly and disassembly operations. In this paper, we address the state of the art in collision detection and the implications it has on the effectiveness of our simulation. In particular, we focus on the usability of current collision detection libraries and discuss some of their limitations. Also, techniques to improve the robust ness of object interactions, in support of a collision detection algorithm, are presented. Although HIDRA is focused on assembly and disassembly simulations, the techniques described are relevant for the broader development of haptically enabled simulations.
Solid Modelling Through Constraint-Based Manipulations in a Virtual Reality Environment
Authors: Zhong Yongmin , Mu¨ller-Wittig Wolfgang
Published: June 2008

Virtual Reality (VR) technology is a natural extension of 3D computer graphics with advanced input and output devices and brings a completely new environment to the CAD community. However, with today’s VR systems, it is difficult to directly and precisely create and modify objects in a VR environment. This paper presents an efficient approach for solid modelling in a VR environment. Solid modelling in the VR environment is precisely performed in an intuitive manner through precise constraint-based manipulations. Constraint-based manipulations are accompanied with automatic constraint recognition and precise constraint satisfaction for establishing the hierarchically structured constraint-based data model and are realized by allowable motions for precise 3D interactions in the VR environment. The allowable motions are represented as a mathematical matrix for conveniently deriving the allowable motions from constraints. A procedure-based degree-of-freedom incorporation method for 3D constraint solving is presented for deriving the allowable motions. A rule-based constraint recognition engine is developed for automatic constraint recognition. A prototype system has been developed for solid modelling in the VR environment, where the user can create solid models in an intuitive manner through precise constraint-based manipulations.
Validation of Virtual Crane Behavior Through Comparison With a Real Crane
Authors: Taylor Frank , Jayaram Sankar , Jayaram Uma , Mitsui Tatsuki
Published: June 2008

A module has been developed for virtual assembly systems allowing them to more realistically simulate heavy machinery assembly. The module provides a virtual overhead crane for manipulating heavy assembly components and physically based motion of components attached to the crane. This paper shows validation of the heavy machinery virtual assembly module by performing real world tasks in the virtual environment. More importantly, it compares the simulated motions of the crane and attached load in the virtual environment with motions of a real crane and attached load. The results show a correlation between the virtual and real world for the crane velocity and acceleration, as well as angular displacement and damped motion of the attached load due to crane acceleration.
AR-PDA: A Personal Digital Assistant for VR/AR Content
Authors: Fruend Juergen , Matysczok Carsten , Ebbesmeyer Peter , Maciej Joerg
Published: June 2008

This paper describes the development of an AR-based hard- and software system for a mobile digital assistant (AR-PDA). Target group for using this system is the large group of consumers. Here the AR-PDA uses AR technology to efficiently support users during their daily tasks. The technical realization of the system is based on 3rd generation video supported mobile phones. The user visualizes real objects with the AR-PDA. An integrated camera takes the pictures and the AR-PDA sends the video stream by mobile radiocommunication (e.g. UMTS) to the AR server. The server recognizes the objects by analyzing the image and establishes the relevant context-sensitive information, which is added to the video stream as multimedia elements (e.g. sound, video, text, images or virtual objects) and then sent back to the AR-PDA. The function validity is shown on the basis of close to practice application scenarios in the scope of household appliances.
A Fuzzy Logic Trail Finding Algorithm Trained With Human Knowledge
Authors: Kinney Charles , Edwards Dean B.
Published: June 2008

This paper presents a method for developing a fuzzy logic trail finding algorithm using a technique called embedding human knowledge. The trail finding algorithm was trained to find the pixels in images that closely resemble those that were classified as belonging to a forest trail by a human analyst. The relationship of the fuzzy logic system to a classical logic system is discussed as a method for training the fuzzy sets to mimic a human. The results show that the method outlined in this paper reduced the error in the fuzzy logic system by 99%. More generally, this method can be applied to many different situations to find features in images quickly and effectively.
Development of a Computer Controlled Valve System for an Internal Combustion Engine
Authors: Sullivan Paul , Petersen Harry
Published: June 2008

A newly emerging method of improving gas mileage and emissions from spark ignition engines is by computer control of the operation of the engine intake and exhaust valves. By controlling valve timing and duration the elimination of the throttle, a source of pumping loses can be minimized. One system is now in production by BMW, which uses a mechanism that varies the rocker arm ratio to vary the intake valve’s lift. As part of two Senior Design Projects a spark ignition internal combustion engine was modified at Minnesota State University, Mankato, to allow computer control of the engine’s valves. These projects worked at replacing the mechanically operated intake and exhaust valves with pneumatically operated valves controlled by computer in the form of a Programmable Logic Controller. The valves controlled by the solenoids switched compressed air to pneumatic cylinders that operate the existing poppet intake and exhaust valves on the engine. This paper will present the background, operational issues, and the initial results of the project.
The Synaps Pointer Optimization Engine
Authors: Van der Velden Alex , Kokan David
Published: June 2008

This paper describes a innovative optimization algorithm called Pointer. The Pointer software consists of a complementary set of optimization algorithms: linear simplex, sequential quadratic programming (SQP), downhill simplex, and genetic algorithms. Pointer can efficiently solve a wide range of problems in a fully automatic manner due to a special automatic control algorithm. The goal of the Pointer software is to make optimization more accessible to non-expert users without sacrificing performance.
Web-Based Design Coordination
Authors: Domeshek Eric A. , Holman Elias
Published: June 2008

This paper reports on a web-based groupware tool intended to support large distributed teams of engineers in modern engineering design practice. The Advanced Design Coordination Tool (ADCT) presents itself to members of a design team as a shared on-line set of engineers’ notebooks with flexible editing, filing, viewing, browsing, and searching capabilities. Additionally, its use of product, process, and decision representations referencing an explicit domain ontology, and tied together by dependency links, introduces artificial intelligence technology that enables capabilities beyond simple unstructured design history capture. The resulting repository can capture a rich and structured design rationale, which, with the system’s state management and versioning capability, enables recording active as well as rejected alternatives. The system currently exploits the captured data to improve team coordination: it applies dependency processing algorithms to automatically generate notifications to appropriate team members, based on changes to design notes or the detection of design conflicts. Over time, the accumulation of structured design histories with rationales should provide the basis for a knowledge repository that can proactively offer advice on new design challenges. This paper first sketches the context that makes this tool desirable, and then describes the system’s design and key capabilities. We finish with a discussion of limitations and future enhancements.
An Integrated Computer-Aided Data Acquisition and Control System
Authors: Khosrowjerdi Mohammad , Aflaki James
Published: June 2008

PC-based data acquisition systems are used in a wide variety of applications. In laboratories, in field services and in manufacturing facilities, these systems act as general-purpose measurement and control tools well suited for measuring voltage signals. Teaching and learning experiences may be enhanced by integrating new-technologies in the engineering curriculum, particularly in experimental-type courses. By installing plug-in data acquisition boards and signal-conditioning hardware, and appropriate software, the general-purpose computers become enormously flexible virtual-instruments with data acquisition and analysis capability. This paper describes a Computer-Aided Testing System which uses a commercially available A/D board to offer users a wide array of measurement and control capabilities. It can be used for making repeated high speed measurement, controlling motors or teaching data acquisition.
Geometric Reasoning for Evaluation Criteria in Intelligent Tutoring System for Introductory Figural Space Design
Authors: Lim Jin Seung , Kim Yong Se , Wang Eric , Dicker James
Published: June 2008

The ability of an engineer and an architect to visualize and reason about geometric aspects of physical objects and processes is crucial to the success of their professional activities. This visual reasoning capability forms the essential foundation for engineering and architecture education. This paper describes the Figural Space Design problem in the architectural design module of the Visual Reasoning Tutor (VRT) system. Specifically, geometric reasoning methods developed to provide evaluation of the student solution in an introductory figural space design problem using four sticks are described in this paper together with the pedagogy of the problem.
Development of a Digital Lectern for Teleteaching
Authors: Kunz Andreas M. , Kennel Thomas , Hugentobler Urs
Published: June 2008

Increased capacity of the network will also provide the possibility to transmit pictures and sound. This is of particular interest if speeches, presentations or lectures have to be recorded or transmitted in order to make them accessible at a different location or to a larger auditorium. Very often additional information has to be transmitted simultaneously as for example the visualization of overhead slides or PowerPoint presentations with additional annotations. Up to now this has not been possible or only with a large number of staff and financial expenditure and thus is refused in many cases. This paper describes the construction and the functionality of a digital lectern named “Speaker’s Corner” that solves the problems described above and also allows the use of conventional media.
Computational Study of Film-Cooling Effectiveness on a Low-Speed Airfoil Cascade: Part I — Methodology and Validation
Authors: Walters D. Keith , Leylek James H.
Published: June 2008

Computational fluid dynamics (CFD) results are presented for a study of film cooling on a linear turbine airfoil cascade. The simulations are for a single-row of streamwise-injected cylindrical holes on both the pressure and suction surfaces, downstream of the leading edge. The cases considered match experimental efforts previously documented in the open literature. Results are obtained for density ratio equal to 2.0, and a blowing ratio range from 0.5 to 2.0. The computational methodology minimizes error due to geometry modeling, grid, and numerical scheme, placing the simulations against the limits of the turbulence modeling. A commonly available two-equation turbulence model is used in combination with a two-layer near-wall treatment, and its performance is highlighted. Results are compared to experimental data in terms of downstream adiabatic effectiveness, and conclusions are drawn regarding the performance of the current approach.
Computational Study of Film-Cooling Effectiveness on a Low-Speed Airfoil Cascade: Part II — Discussion of Physics
Authors: Walters D. Keith , Leylek James H.
Published: June 2008

Computational fluid dynamics (CFD) results are presented for a study of film cooling on a linear turbine airfoil cascade. The simulations are for a single-row of streamwise-injected cylindrical holes on both the pressure and suction surfaces, downstream of the leading edge. The cases considered match experimental efforts previously documented in the open literature. Results are obtained for density ratio equal to 2.0, and a blowing ratio range from 0.5 to 2.0. The computational methodology minimizes error due to geometry modeling, grid, and numerical scheme, placing the simulations against the limits of the turbulence modeling. In this part, the results are examined in order to highlight the mean-flow physical mechanisms responsible for film-cooling performance on airfoils.
Experimental Investigation of Heat Transfer in Two-Pass Coolant Passages With Ribs and Film Cooling Hole Ejection
Authors: Chanteloup D. , Bo¨lcs A.
Published: June 2008

A study of flow in two stationary models of two-pass internal coolant passages is presented, which focuses on the heat transfer characteristics in the two-pass coolant channel. Heat transfer measurements were made with a transient technique using thermochromic liquid crystal technique to measure a surface temperature. The technique allows full surface heat transfer coefficient measurements on all the walls. The coolant passage model consisted of two square passages, each having a 20 hydraulic diameter length, separated by a rounded-tip web of 0.2 passage widths, and connected by a sharp 180 deg bend with a rectangular outer wall. Ribs were mounted on the bottom and top walls of both legs, with a staggered arrangement, and at 45 deg to the flow. The rib height and spacing were 0.1 and 1.0 passage heights, respectively. The measurements were obtained for Reynolds numbers of 25000, 50000 and 70000. One geometry is equipped with extraction holes to simulate holes for film cooling. Two series of holes are placed solely in the bottom wall, 4 holes are located in the bend, and 12 in the downstream leg. The global extraction through the holes was set to 30%, 40% and 50% of the inlet massflow. This paper presents new measurements of the heat transfer in the straight legs, and in the bend of the passage. It shows the influence of Reynolds number and extraction on full surface measurements and area averaged results.
Progressive Solid Models for Internet-Based Design and Collaboration
Authors: Lee Jae Yeol , Lee Joo-Haeng , Kim Hyun , Kim Hyung Sun
Published: June 2008

Progressive mesh representation and generation have become one of the most important issues in network-based computer graphics. However, current researches are mostly focused on triangular mesh models. On the other hand, solid models are widely used in industry and are applied to advanced applications such as product design and virtual assembly. Moreover, as the demand to share and transmit these solid models over the network is emerging, the representation and the generation of progressive solid models depending on specific engineering needs and purpose are essential. In this paper, we present a Cellular Topology-based approach to generating progressive solid models from a feature-based solid model for internet-based design and collaboration. The proposed approach introduces a new scheme for storing and transmitting solid models over the network. The Cellular Topology (CT) approach makes it possible to effectively generate progressive solid models and to efficiently transmit the models over the network with compact model size. Thus, an arbitrary solid model SM designed by a set of design features is stored as a much coarser solid model SM0 together with a sequence of n detail records that indicate how to incrementally refine SM0 exactly back into the original solid model SM = SMn.
A Distributed Multidisciplinary Design Optimization Framework Based on Web and Agents
Authors: Shen Weiming , Ghenniwa Hamada H.
Published: June 2008

Web technology is playing an increasingly important role in collaborative product development systems. However, most Web-based applications were developed using client/server architecture for information sharing. This paper presents some results of an on-going research project on developing a distributed multidisciplinary design optimization (MDO) framework based on Web and agents. The primary objective is to develop an architectural framework for implementing MDO environments by integrating intelligent agents and Internet/Web based technologies. The principle is to leverage the right technology for the appropriate purpose. Agent-based negotiation is used for computing resource management or load balancing. Web-based interfaces are developed for users to access the MDO software environment and collaborate with each other. Active Web servers provide a way to integrate legacy systems separated by firewalls. The paper describes the proposed framework; presents a prototype environment for blow molded automotive parts design; and addresses some key issues in system implementation.
Web-Based Finite Element Mesh Generator for Testing Behavior of Steel Building Connections in Virtual Environment
Authors: Abolmaali Ali , Razavi Hadi
Published: June 2008

This study presents development of a Web-based Finite Element Method (FEM) module, which creates model-virtual experimentations (MVE) for double web angle, top and seat angle, flush end-plate, and extended end-plate connections. The MVE mimics the real test set-up for monotonic and cyclic types of experiments in a Web-based virtual environment to be used for conducting virtual experiments to obtain load-deformation characteristics of the aforementioned connections being developed by the authors. The MVE’s library contains three dimensional isoparametric elements with and without internal nodes to eliminate shear errors. The MVE module and its output will contain graphical and visualization capability, and it will be accessible to researchers and students on the web. The Web-based client applications are developed such that it will access the MVE program running on a centralized server. The user is capable of changing parameters of visualization such as connection’s geometric variables or test beam and columns dimensions for real time recreation of MVE.
Program Synthesis of FEA Constitutive Behavior Modules Through Data Driven Design Optimization
Authors: Michopoulos J. G.
Published: June 2008

Design optimization in the context of finite element modeling (FEM) and analysis (FEA) has been traditionally used to help designers determine optimal structural geometry and/or material property parameters according to objective functions of interest and necessary constraints. In the present paper it is attempted to generalize the design optimization methodology into a program synthesis technique for determining the code necessary to encapsulate the constitutive behavior of the material system required for generalized FEA applications. The core concept behind the methodology followed by our group in the past, has been the experimental identification of a dissipated energy density (DED) function for polymer matrix composites (PMCs) through a non-linear optimization scheme for determining the free coefficients of the sum of the basis functions that are used to construct the DED function and is based on the energy balance of the specimen under testing. The utilized testing generated massive amounts of experimental data that would be produced by exposing PMC specimens to multidimensional loading paths with the help of custom made multi-axial computer-controlled testing machines. The variety of custom environments utilized to implement the analytical and numerical details has often created difficulties in transferring our technology to end users in the design and material communities. The present implementation was greatly enabled by recent advances in finite element techniques and “of the shelf” design optimization integration technologies along with the parallel hardware and software evolution. The program synthesis lies on a process that automatically generates the code of a user material subroutine through minimization of the error between measured and simulated specimen behavior. The generated code can be subsequently used with any geometry and loading specification definable within the limits of the non-linear element library in commercial codes such as ANSYS and ABAQUS.
Rationalization and Computer Modeling of GD&T Classes
Authors: Wu Yanyan , Shah Jami J. , Davidson Joseph K.
Published: June 2008

The main focus of this research is to develop a mathematical model for GD&T (Geometric Dimensioning and Tolerancing) to support tolerance specification, validation and tolerance analysis. The model should be built on the clear definition of GD&T, both in terms of semantics and syntax. The current tolerance standards (Y14.5M-1994 and ISO 1101-1983) have many inconsistencies. We present a rational basis for GD&T by examining the basic elements involved in geometric variation and their interrelations. Tolerance classes are defined in terms of a target, a datum reference frame, and geometric relations. The GD&T global model developed is the basis for a set of computer tools for automatically generating and validating dimension and tolerance specifications based on the functionality of the part, checking dimensioning status and tolerancing status, and applying GD&T advisor.
An Automated and Optimal Tool Path Planning System for the 3-1/2-1/2-Axis CNC Maching of Sculptured Parts
Authors: Chen Zezhong C. , Dong Zuomin , Vickers Geoffrey W.
Published: June 2008

Some sculptured parts with complex free-form surfaces usually require expensive 5-axis CNC machining. In this work, a cost-effective and practical solution to the 5-axis sculptured part machining – 3-1/2-1/2-axis CNC machining scheme – is discussed. An automatic and optimal tool path planning system for 3-1/2-1/2-axis CNC machining is introduced. The system uses fuzzy pattern recognition method and Voronoi diagram to subdivide a complex sculptured surface into an optimal number of uniform surface patches, finds the optimal cutter/part orientation for each surface patch, and plans 3-axis CNC tool paths for them. This type of machining is carried out by rotating the part to the cutter/part orientations discretely and sequentially using a tilt-rotary table attached to the 3-axis CNC machine. Under each orientation, the corresponding surface patch is machined using the 3-axis CNC tool paths. This tool path planning system can automatically generate efficient tool paths for sculptured parts and make the 3-1/2-1/2-axis CNC machining scheme as an applicable alternative of 5-axis CNC machining method.
Hybrid Cutter Path Generation for 2.5D Milling Operation
Authors: Yao Zhiyang , Gupta Satyandra K. , Nau Dana S.
Published: June 2008

2.5D milling operation is widely used in a variety of applications. Generating efficient cutter path for 2.5D milling operation is very important in order to shorten total machining time and thus enhance overall throughput. However, most existing cutter path generation algorithms do not produce highly efficient cutter paths for certain type of complex pockets. The reason behind this is as following. For different types of pocket geometries, different types of cutter paths have been shown to be efficient. However, in certain types of complex pockets, no single type of cutter path produces efficient path throughout the pocket. Hybrid cutter paths, where different portions of the complex pocket have different types of paths, appear to be promising idea for generating efficient cutter path. However, currently only limited work has been devoted to generating hybrid cutter paths automatically. In this paper, we systematically analyze different cutter path generation strategies, and discuss several existing heuristics. Based on our observations, we propose two algorithms for generating hybrid cutter path, i.e., a greedy algorithm using heuristics and a branch and bound search algorithm, which can find efficient hybrid cutter path for complex parts.