bluuebunny/crossref_metadata_2025 huggingface dataset:
Does Plasticity of the GABAA Reversal Potential Contribute to Epileptogenesis?
Authors: Staley Kevin J.
Published: June 2008

Disrupted Dentate Granule Cell Chloride Regulation Enhances Synaptic Excitability during Development of Temporal Lobe Epilepsy. Pathak HR, Weissinger F, Terunuma M, Carlson GC, Hsu FC, Moss SJ, Coulter DA. J Neurosci 2007;27(51):14012–14022. GABAA receptor-mediated inhibition depends on the maintenance of intracellular Cl- concentration ([Cl-]in) at low levels. In neurons in the developing CNS, [Cl-]in is elevated, EGABA is depolarizing, and GABA consequently is excitatory. Depolarizing GABAergic synaptic responses may be recapitulated in various neuropathological conditions, including epilepsy. In the present study, rat hippocampal dentate granule cells were recorded using gramicidin perforated patch techniques at varying times (1–60 d) after an epileptogenic injury, pilocarpine-induced status epilepticus (STEP). In normal, non-epileptic animals, these strongly inhibited dentate granule cells act as a gate, regulating hippocampal excitation, controlling seizure initiation and/or propagation. For 2 weeks after STEP, we found that EGABA was positively shifted in granule cells. This shift in EGABA altered synaptic integration, increased granule cell excitability, and resulted in compromised “gate” function of the dentate gyrus. EGABA recovered to control values at longer latencies post-STEP (2–8 weeks), when animals had developed epilepsy. During this period of shifted EGABA, expression of the Cl-extruding K+/Cl- cotransporter, KCC2 was decreased. Application of the KCC2 blocker, furosemide, to control neurons mimicked EGABA shifts evident in granule cells post-STEP. Furthermore, post-STEP and furosemide effects interacted occlusively, both on EGABA in granule cells, and on gatekeeper function of the dentate gyrus. This suggests a shared mechanism, reduced KCC2 function. These findings demonstrate that decreased expression of KCC2 persists for weeks after an epileptogenic injury, reducing inhibitory efficacy and enhancing dentate granule cell excitability. This pathophysiological process may constitute a significant mechanism linking injury to the subsequent development of epilepsy.
Thrombin: Is it on a PAR with Seizures and Epilepsy?
Authors: Kelly Kevin M.
Published: June 2008

Thrombin Induces Long-Term Potentiation of Reactivity to Afferent Stimulation and Facilitates Epileptic Seizures in Rat Hippocampal Slices: Toward Understanding the Functional Consequences of Cerebrovascular Insults. Maggio N, Shavit E, Chapman J, Segal M. J Neurosci 2008;28(3):732–736. The effects of thrombin, a blood coagulation serine protease, were studied in rat hippocampal slices, in an attempt to comprehend its devastating effects when released into the brain after stroke and head trauma. Thrombin acting through its receptor, protease-activated receptor 1 (PAR1), produced a long-lasting enhancement of the reactivity of CA1 neurons to afferent stimulation, an effect that saturated the ability of the tissue to undergo tetanus-induced long-term potentiation. This effect was mediated by activation of a PAR1 receptor, because it was shared by a PAR1 agonist, and was blocked by its selective antagonist. An independent effect of thrombin involved the lowering of the threshold for generating epileptic seizures in CA3 region of the hippocampus. Thus, the experiments in a slice mimicked epileptic and cognitive dysfunction induced by thrombin in the brain, and suggest that these effects are mediated by activation of the PAR1 receptor.
KCTD5, a putative substrate adaptor for cullin3 ubiquitin ligases
Authors: Bayón Yolanda , Trinidad Antonio G. , de la Puerta María L. , del Carmen Rodríguez María , Bogetz Jori , Rojas Ana , De Pereda José M. , Rahmouni Souad , Williams Scott , Matsuzawa Shu‐ichi , Reed John C. , Crespo Mariano Sánchez , Mustelin Tomas , Alonso Andrés
Published: June 2008

Potassium channel tetramerization domain (KCTD) proteins contain a bric‐a‐brac, tramtrak and broad complex (BTB) domain that is most similar to the tetramerization domain (T1) of voltage‐gated potassium channels. Some BTB‐domain‐containing proteins have been shown recently to participate as substrate‐specific adaptors in multimeric cullin E3 ligase reactions by recruiting proteins for ubiquitination and subsequent degradation by the proteasome. Twenty‐two KCTD proteins have been found in the human genome, but their functions are largely unknown. In this study, we have characterized KCTD5, a new KCTD protein found in the cytosol of cultured cell lines. The expression of KCTD5 was upregulated post‐transcriptionally in peripheral blood lymphocytes stimulated through the T‐cell receptor. KCTD5 interacted specifically with cullin3, bound ubiquitinated proteins, and formed oligomers through its BTB domain. Analysis of the interaction with cullin3 showed that, in addition to the BTB domain, some amino acids in the N‐terminus of KCTD5 are required for binding to cullin3. These findings suggest that KCTD5 is a substrate‐specific adaptor for cullin3‐based E3 ligases.
New polymorphic dinucleotide and trinucleotide microsatellite loci for hop Humulus lupulus L.
Authors: JAKSE J. , LUTHAR Z. , JAVORNIK B.
Published: June 2008

One hundred and thirty‐five microsatellite markers were developed for hop Humulus lupulus L. from di‐ and trinucleotide‐enriched libraries. Seventy‐eight primers showed amplification in two tested genotypes. Twenty‐four loci were further characterized on a population of 34 hop samples and the number of alleles per locus, observed heterozygosity and expected heterozygosity ranged from two to 20 (9.7 on average), from 0.0294 to 0.9412 (0.6234 on average) and from 0.0294 to 0.9170 (0.6720 on average), respectively. These microsatellite markers will be further used for studying population structures and relationships and for identifying important qualitative and quantitative loci of hop.
Development of cytochrome b primers for mitotyping of barbels (Barbus spp.)
Authors: GANTE H. F. , ALVES M. J. , DOWLING T. E.
Published: June 2008

Primers were developed that allow for rapid, reliable and inexpensive screening of cytochrome b by analysis of single‐stranded conformational polymorphisms. Twenty different haplotypes were identified from six species of Iberian Barbus. These primers proved useful for population and species level studies, and could also be valuable in population genetic and phylogenetic studies of other cyprinin fishes.
Accurate methods of DNA extraction and PCR‐based genotyping for single scallop embryos/larvae long preserved in ethanol
Authors: ZHAN AIBIN , BAO ZHENMIN , HU XIAOLI , LU WEI , WANG SHI , PENG WEI , WANG MINGLING , HUI MIN , HU JINGJIE
Published: June 2008

Marine scallops are sessile as adult but have a long planktonic larval phase showing great possibility to migrate in marine realm lacking of obvious barriers. Genetic analysis of scallop embryos/larvae based on molecular markers is very essential to clarify the spatial and temporal gene flow and the unique population and community structure. However, the technical challenges, such as single embryos/larvae isolation and low quantity and poor quality of DNA extracted, make genotyping for a single embryo/larva long preserved in ethanol to be a really difficult task. In this study, we analysed the factors that might affect the DNA quantity and quality for simple sequence repeat‐based genotyping for single embryos/larvae. Based on the factors analysed, we developed a LoTEPA buffer‐based method, of which the accuracy, stability and reproducibility were evaluated by controlled inter‐ and intraspecies and self‐fertilized scallop families. The genotyping results showed the high success rate of more than 90% in total for embryos/larvae preserved in ethanol for 1–5 years. Furthermore, the successful genotyping for the larvae sampled from a natural habitat well demonstrated the potential use of this method in practical ecological analysis.
SIMIL: an r (CRAN) scripts collection for computing genetic structure similarities based on structure 2 outputs
Authors: NADIR ALVAREZ , NILS ARRIGO , CONSORTIUM INTRABIODIV
Published: June 2008

The emergence of comparative phylogeography requires tools that allow comparing quantitatively the genetic structures between species. Whereas numerous methods have been developed to compare trees inferred from two species, comparison methods involving population structures issued from Bayesian inferences or maximum likelihood criterion have been poorly investigated. Here, we present a method implemented in an r (CRAN) scripts collection, SIMIL, based on the mean absolute differences computed from structure 2 outputs. The scripts collection is illustrated by the computation of unweighted and weighted genetic‐structure‐similarity (GSS) indices in three alpine plants. Different weighting procedures — taking into account the level of overlap between the species sampling areas — are compared among the different species pairs and among the different numbers of gene pools considered in structure.
Isolation of compound microsatellite loci in the herbaceous perennial Cirsium purpuratum (Maxim.) Matsum.
Authors: WU BINGYUN , SHIOKAWA AKIKO , MATSUSHITA NORIHISA , HOGETSU TAIZO
Published: June 2008

The herbaceous perennial Cirsium purpuratum is a pioneer on the southeast side of Mount Fuji in Japan. For genetic analysis of reproduction in this species, we developed polymorphic compound microsatellite markers using an adaptor‐ligated library method and a simpler method called the intercompound microsatellite method. The latter method was an effective method for developing compound simple sequence repeat markers. In total, 11 polymorphic, codominant microsatellite markers were developed and characterized for this species. These polymorphic markers had three to 20 alleles per locus, a range of observed heterozygosity from 0.25 to 0.90, and were considered effective for genetic analysis.
Characterization of 12 highly variable tetranucleotide microsatellite loci for Arctic grayling (Thymallus arcticus) and cross amplification in other Thymallus species
Authors: DIGGS MATTHEW D. , ARDREN WILLIAM R.
Published: June 2008

We describe the isolation and development of 12 polymorphic tetranucleotide microsatellite loci for Arctic grayling (Thymallus arcticus). In a sample of 46 fish, we observed between three and 20 alleles per locus. All 12 of these loci were also polymorphic in at least one of the following Thymallus species and subspecies: T. burejensis, T. amurensis, T. thymallus, T. brevirostris, T. grubii, T. arcticus baicalensis and T. arcticus pallasi. These loci will aid in our understanding of the population genetics, behaviour and conservation of grayling species throughout the northern hemisphere.
Identification of 20 polymorphic microsatellite loci in European crow (Corvus corone) from existing passerine loci
Authors: HAAS FREDRIK , HANSSON BENGT
Published: June 2008

The European crow (Corvus corone) occurs in two subspecies (or species) with distinct plumage coloration: the black carrion crow (C. c. corone) and the grey and black hooded crow (C. c. cornix). We tested 42 passerine microsatellite loci for amplification in the European crow and identified 20 loci that were both polymorphic and easy to score. In 50 individuals sampled in the Danish part of the species’ pan‐European hybrid zone, the number of alleles ranged between two and 21. One locus deviated from Hardy–Weinberg equilibrium and had a high estimated null allele frequency. These 20 loci were highly successful in amplifying polymorphic products also in other crow populations and in another Corvidae species, the rook (Corvus frugilegus).
Isolation and characterization of microsatellite loci in Coccoloba cereifera (Polygonaceae), an endangered species endemic to the Serra do Cipó, Brazil
Authors: MOREIRA RENNAN G. , MCCAULEY ROSS A. , CORTÉS‐PALOMEC AUREA C. , LOVATO M. BERNADETE , FERNANDES G. WILSON , OYAMA KEN
Published: June 2008

Microsatellite primers were isolated from the microendemic and threatened species Coccoloba cereifera, a shrub known only from a small region in the Serra do Cipó, Brazil. Thirteen primer pairs amplifying perfect and imperfect microsatellite regions were tested in 40 individuals from the one known occurrence of the species. Number of alleles ranged from two to six and levels of observed heterozygosities ranged from 0.21 to 0.95. These markers will be useful for the analysis of questions concerning population genetic structure and will assist in providing information for future conservation management programmes.
Isolation and characterization of polymorphic microsatellite and COI loci from the whelk Kelletia kelletii
Authors: WHITE CROW , TOONEN ROBERT J.
Published: June 2008

There is considerable interest in the genetic structure of Kelletia kelletii because of its economic, ecological and scientific importance. To that end, we developed species‐specific primers which amplify mitochondrial cytochrome c oxidase subunit I as well as 13 hypervariable nuclear microsatellite loci. Using dye‐labelled primers, the microsatellite loci can be co‐amplified in two multiplex polymerase chain reactions and scored simultaneously on an automated sequencer.
Pseudoexfoliation as a risk factor for prevalent open‐angle glaucoma
Authors: Ekström Curt , Alm Albert
Published: June 2008

Purpose:  To estimate the risk of open‐angle glaucoma (OAG) associated with exposure to pseudoexfoliation (PEX) and increased intraocular pressure (IOP).

Methods:  In 1984−86, a cross‐sectional, population‐based survey was conducted in the municipality of Tierp, central Sweden. Its target population comprised 2429 residents aged 65–74 years. In addition to a sample of 760 people, patients previously diagnosed with glaucoma were examined. The prevalence of OAG in the target population was estimated from the prevalence in the sample and patients already diagnosed. A review of prevalent cases in 1984–86 was undertaken in 2006.

Results:  Definite OAG was established in 77 cases, corresponding to a prevalence of 5.3% (95% confidence interval [CI] 4.4–6.2). Of these, 23 represented newly detected cases. The prevalence of PEX was 17.2% (95% CI 14.6–19.9), calculated from 134 cases in the population sample. When adjusting for gender, PEX was associated with a 4.7‐fold (95% CI 2.2–9.4) increased risk of OAG. For clinical cases only, the risk was 16‐fold (95% CI 4.8–56) greater in subjects with PEX, compared with those without PEX. In individuals without a previous diagnosis of glaucoma, an IOP ≥ 20 mmHg was associated with a 9.7‐fold (95% CI 3.7–27) increased risk, but PEX alone was not a risk factor for OAG (adjusted odds ratio = 0.96).

Conclusions:  Pseudoexfoliation was associated with OAG only in people previously diagnosed with the disease. In cases detected in the population‐based survey, increased IOP was a serious risk factor.
Role of the amino and carboxy termini in isoform‐specific sodium channel variation
Authors: Lee Annie , Goldin Alan L.
Published: June 2008

Nav1.2 and Nav1.6 are two voltage‐gated sodium channel isoforms found in adult CNS neurons. These isoforms differ in their electrophysiological properties, even though the major regions that are known to be involved in channel activation and inactivation are conserved between them. To determine if the terminal domains of these channels contributed to their activation and fast inactivation differences, we constructed chimeras between the two isoforms and characterized their electrophysiological properties. Exchanging the N‐terminal 205 amino acids of Nav1.6 and the corresponding 202 amino acids of Nav1.2 completely swapped the V_1/2 of steady‐state activation between the Nav1.2 and Nav1.6 channels in an isoform‐specific manner. Exchanging the C‐terminal 436 amino acids of Nav1.6 and the corresponding region of Nav1.2 altered the voltage dependence and kinetics of steady‐state inactivation, but the changes did not reflect a direct transfer of inactivation properties between the two isoforms. Finally, the N‐ and C‐terminal domains from Nav1.6 demonstrated functional cooperation. These results suggest that the terminal sequences of the sodium channel are important for isoform‐specific differences between the channels.
Retinal ganglion cells in diabetes
Authors: Kern Timothy S. , Barber Alistair J.
Published: June 2008

Diabetic retinopathy has long been recognized as a vascular disease that develops in most patients, and it was believed that the visual dysfunction that develops in some diabetics was due to the vascular lesions used to characterize the disease. It is becoming increasingly clear that neuronal cells of the retina also are affected by diabetes, resulting in dysfunction and even degeneration of some neuronal cells. Retinal ganglion cells (RGCs) are the best studied of the retinal neurons with respect to the effect of diabetes. Although investigations are providing new information about RGCs in diabetes, including therapies to inhibit the neurodegeneration, critical information about the function, anatomy and response properties of these cells is yet needed to understand the relationship between RGC changes and visual dysfunction in diabetes.
Design and Manufacturing Methodology for Mechanical Systems Using Virtual Product Simulator
Authors: Hashima Masayoshi , Senta Yosuke , Sato Yuichi
Published: June 2008

In mechanical systems development, it is well known that verification tests covering all aspects of mechanics, software, and hardware cannot be performed until a working prototype of the product is completed. As a result, serious flaws may be not discovered until the final stages of development, resulting in delays and extra work, mainly on the embedded software (known as firmware). We propose a new design and manufacturing methodology for mechanical systems that is based on a 3D real-time simulator, called “VPS” (Virtual Product Simulator). This simulator enables the development of virtual mechanical models on computers, allowing engineers to work on the model without seeing the actual device. It provides more time to thoroughly test the whole system, thereby, making the development process more efficient.
Design of a Haptic Device for Weight Sensation in Virtual Environments
Authors: Gurocak Hakan , Parrish Benjamin , Jayaram Sankar , Jayaram Uma
Published: June 2008

The research presented in this paper is the design and implementation of a force feedback hand master called AirGlove. The device uses six ports arranged in a Cartesian coordinate frame setting to apply a point force to the user’s hand. Compressed air is exhausted through the ports, creating thrust forces. The magnitude and direction of the resultant force are controlled by changing the flow rate of the air jets and by activating different ports. The AirGlove can apply an arbitrary point force to the user’s hand. However, the main goal of this research is to reflect gravitational forces to the user so that sensation of weight of a virtual object can be created. After introduction of the main concept of the AirGlove, the paper presents design and implementation details of the device. Integration of the AirGlove with a virtual assembly system called VADE is explained next. Finally, details of experiments with the device are presented and discussed. Results indicate that users wearing the AirGlove can feel a minimum weight of about 100 grams and the device can create a fairly realistic weight sensation.
Collaborative Virtual Design Environments: A Treatise of the Supporting Technologies
Authors: Horva´th Imre , Rusa´k Zolta´n , Vergeest Joris S. M.
Published: June 2008

The fourth generation of CAD/E systems appears in the form of collaborative virtual design environments (CVDEs). These distributed design support systems are based on a still developing new paradigm. Consequently, the standard architecture, functionality, and implementation of CVDEs are not fully elaborated yet. It is believed that six fundamental components are needed for a fully featured implementation: i. enhanced CAD/E kernel functionality, ii. multi-site imagining and advanced interaction, iii. high-speed communication and multi-channel networking, iv. collaboration support and virtual presence, v. knowledge asset management, and vi. interface to virtual enterprises. This paper investigates the supporting technologies with the aim to explore what is available, satisfactory, compatible, and experienced. The authors found that remarkable results have been achieved in terms of the supporting technologies, but for some CVDEs functions the technologies are not available so far. Currently the largest problem is to integrate the highly heterogeneous technologies into one coherent system. This is due partly to the inherent complexity of the problem, and partly to the uneven maturity of the technologies. It can be predicted without any hazard that dramatic changes will be witnessed soon in this front of research and development.
Tracker Modalities for Virtual Environments: A Comparison of Some Performance Characteristics
Authors: Repp Roglenda , Jayaram Uma
Published: June 2008

In this paper the authors present a comparison of some performance characteristics of two motion tracking modalities for use in a virtual environment. Ascension Technology’s Flock of Birds is an electromagnetic tracking system. Intersense’s IS-600 uses a combination of ultrasonic, infrared, and inertial principles. Case studies were performed for both tracking systems to study static distortion, temporal stability, and the effect of metal. The requirements of the virtual reality application would ultimately guide the choice of the tracker modality.
An Evolutionary Approach to the Identification of Linkage Curves
Authors: Li Hongjie , Wang Gary , Xiao Renbin
Published: June 2008

Identification of an appropriate linkage curve is an important step in the application of linkage mechanisms. This paper applies a new identification method, evolutionary identification, to search tbr the curve based on the analogy of species evolution. In this method, features of general linkage curves are defined and represented as evolutionary factors, or “genes”. Then the evolutionary factors are operated through evolutionary computation. This method can automatically identity the curve with the maximum similarity and thus obtain the structural parameters of the curve from the atlas base of linkage curves. General principles are also given for the evolutionary identification approach as a new identification method. The proposed method has been coded and applied in real linkage design problems. Further research topics are also discussed.
Case Studies on the Application of the Abstract Prototyping Strategy in the Development of Design Support Software
Authors: Opiyo Eliab Z. , Horva´th Imre , Vergeest Joris S. M.
Published: June 2008

The traditional software process models are used in the development of design support software (DSS). They are typically multi phased, and consist of requirements specification, design, implementation, testing and operation as the main phases. One of the goals of phased development is to minimize faults in the delivered codes. Many of the faults can be traced back to the pre implementation phases of requirements specification and design. Reviews are typically performed to remove faults before the requirements or designs are passed to the subsequent phase. The problem is that activities in the phases of software process models, in particular the design phase are coarsely defined and do not scale to precisely match the underlying needs. We have developed a computer based pre-implementation testing methodology called abstract prototyping. It extends the current practices by defining the steps of the design phase of the DSS development process as definition of features, creation or selection of theories, formulation of methods, building of algorithms and implementation of pilot prototypes. Based on this methodology, faults can be traced back to the requirements, theories, methods, algorithms, or pilot prototypes rather than exclusively to the requirements or designs. Under this procedure, reviews are performed to remove faults before the requirements, theories, methods, algorithms, or pilot prototypes are passed to the subsequent stage or phase. Prototypes are used to provide the feel and the look of these work products and specially designed measures are used to estimate the extent to which they fulfill their respective specification requirements. We have applied our methodology to several application cases. The results show that the levels of fulfillment of requirements for theories, methods, algorithms, or pilot prototypes can effectively be estimated and in so doing faults detected sufficiently. In this paper, we first review the problem and present the related works. We then briefly introduce the abstract prototyping concept and present its application case studies.
Development of the Finite Element Modeling Markup Language
Authors: Michopoulos J. G.
Published: June 2008

The finite element modeling Markup Language (femML) effort is addressing the problems of data interpretation and exchange for intra- and inter- application interoperability in the Finite Element Modeling domain. This is achieved through the development of an extensible markup language (XML) variant for finite element model data that will permit the storage, transmission, and processing of finite element modeling data distributed via the World Wide Web and related infrastructure technologies. The focus of this work was to utilize the XML’s power of semantic encapsulation along with the existing and continuously improving associated technology to develop a dialect for exchanging FEM data across various codes with heterogeneous input format syntactic specifications. The main aspects of a finite element definition have been used as archetypes for defining the XML element taxonomy definitions. Namely, the geometry, the material, and the loading aspects of a structural component specification are used to define the first level elements of the associated Document Type Definition (DTD). The element list has been amended with a behavior element specification that represents the solution data to be exchanged or visualized. Various tools have been developed to demonstrate associated concepts along with the ANSYS set of tools.
Design, Analysis, and Simulation of Engineering Systems Over the World Wide Web for Educational Use
Authors: Shiakolas P. S. , Kebrle J. , Chandra V. , Wilhite David
Published: June 2008

This paper presents the use of developed software tools for engineering education accessible via a web browser over the World Wide Web. The primary purpose of this work aims at improving the understanding of engineering fundamentals through interactive real-time simulation. The environment consists of modules for interactive real-time simulation of linear time invariant dynamic systems, and for the synthesis and analysis of planar mechanisms. The user interface enables easy understanding of the required inputs from the user. The outputs are presented in pictorial, graphical and textual forms. In addition to these forms, for the mechanism modules the user has the option to view an animation of the synthesized mechanism. This work demonstrates the ease of implementation, advantages of using this technology to aid in classroom instruction and provides valuable analysis tools to engineering professionals. Examples demonstrating features of the developed tools are presented. Users with Internet access can use the developed modules at http://zodhia.uta.edu/development.
An Optimum Aero-Design Process of Turbine Blades
Authors: Xu C. , Amano R. S.
Published: June 2008

With the development of the advanced technology, the combustion temperature is raised for increased efficiencies. At the same time, the turbine and compressor pressure ratio and the mass flow rate rise; thus causing turbine and compressor blades turning and blade lengths increase. Moreover, the high efficiency requirements had made the turbine and compressor blade design difficult. A turbine airfoil has been custom designed for many years, but an optimization for the section design in a three-dimensional consideration is still a challenge. For a compressor blade design, standard section cannot meet the modern compressor requirements. Modern compressor design has not only needs a custom designed section according to flow situation, but also needs three-dimensional optimizations. Therefore, a good blade design process is critical to the turbines and compressors. A blade design of the turbomachines is one of the important steps for a good turbomachine design. A blade design process not only directly influences the overall machine efficiency but also dramatically impact the design time and cost. In this study, a blade design and optimization procedure was proposed for both turbine and compressor blade design. A compressor blade design was used as a test case. It was shown that the current design process had more advantages than conventional design methodology.
Experimental and Theoretical Analysis of the Flow in a Centrifugal Compressor Volute
Authors: Engeda Abraham
Published: June 2008

Volute scroll, conic diffuser and sudden expansion discharge loss account for 4–6 points of efficiency decrement in a typical centrifugal compressor stage. The flow in a volute is highly comlex. It is strongly believed that understanding of the detailed flow structure in a volute will provide insights on minimizing the losses by isolating the mechanisms that contributes to entropy generation. The result will be more efficient centrifugal compressor product for customers at higher profitability levels for manufacturers. Results of an experimental and theoretical analysis of the flow inside in a single stage centrifugal compressor volute are presented. Experiments were performed at three speeds and eight mass flow rates per speed. Static pressure distributions were mapped on the vaneless diffuser and volute casings. This data gave a good understanding of the flow structure in the volute. A meanline analysis was performed using the experimental results in order to obtain the absolute velocity and flow angle leaving the impeller. The combination of the two data sets was used as boundary conditions for a theoretical analysis. Theoretical results showed the detail flow structures inside the vaneless diffuser and volute with good agreement to the experiment.
On the Impact of Radiation Cooling Due to Soot on NO-Emission From a Small Methane-Fueled Furnace
Authors: Al-Omari Salah-Addin B.
Published: June 2008

The paper studies numerically the thermal NO emission from a small vertical methane-fueled furnace supplied with the fuel through its primary inlet located at its bottom, and with the air via two opposing horizontal air jets perpendicular to the direction of fuel supply. Special emphasis is given to investigating the impact of radiation cooling due to the presence of soot in the flame established inside the furnace on NO emission from the furnace. Hereby two main issues are studied. These are the consequence of the commonly adopted assumption of decoupling soot from the gas phase computations, and the impact of the fuel/air reactivity level on NO concentrations. Results show that a complete decoupling of soot from the gas-phase computations leads, as compared with the case when soot and the gasphase are coupled, to a clear enhancement in soot levels, hence in radiation cooling which basically would depress NO formation. However, the difference in NO emission between the two cases is found to be small. Concerning the reactivity level of the fuel/oxidizer mixture, for the case when the reaction rate is reduced by a factor of 2 the overall amount of soot generated, hence radiation cooling, decreases noticeably. This, although reaction rates here are reduced, is responsible for the higher local temperatures and consequently the higher NO emission observed in this case, as compared with their corresponding levels when fuel/oxidizer reactivity levels increase.
A Web-Based Information Management System for Bus Test Data for the Pennsylvania Transportation Institute
Authors: Nanda Jyotirmaya , Iera Rob , Clarke Stella , Simpson Timothy W. , Klinikowski David
Published: June 2008

Computer-based information management systems have allowed many companies and facilities to greatly improve their data storage and processing capabilities over traditional paper and file methods. The Internet and its associated web-based technologies have further contributed to information processing capabilities. The Federal Transit Administration’s Bus Testing Program, operated by the Pennsylvania Transportation Institute at the Pennsylvania State University requires an upgrade to such a system. Currently, all bus test data is entered directly into a hardcopy report, and data analysis must be performed manually. The objective in this research is to develop an information management system for the bus test data to facilitate access to the data, enable search queries, and perform statistical analyses to examine current trends or predict performance characteristics of future buses. A database has been created in Microsoft Access and linked to a user-friendly graphical user interface developed in Visual Basic for fast and nearly error-free data entry. A web-based infrastructure comprised of HTML, XML, ASP, and customized COM objects is used to display, search, and analyze the bus test data. The resulting information system saves time and money for PTI while enabling easy access to bus test reports.
Procedural Visualization of Manufacturing Processes in Distributed Environment
Authors: Sormaz Dusan N. , Borse Prashant A.
Published: June 2008

Visualization provides a tool to enhance understanding and data representation for information generated from numerical simulations and measurements. Visualization of a manufacturing process provides approximate simulation of machining with alternative process parameters, tool and work piece being examined in action. This paper presents a system that provides for visualization of machining processes. The developments were being carried out with Java and Java3d APIs. The process, feature and work piece geometry data are retrieved from knowledge-based system for generating process animation in Java3d environment. The data structures from Java classes are converting the data into GeometryArray objects using Java3d utilities such as GeometryInfo, Triangulator and others. For process animation, the important classes involved are Morphing, Behavior and various interpolators. The complete process animation is guided using a single alpha timer object with supplementary geometry arrays generating realistic machining process. Prototype has been implemented so that it accepts data (tool, feature, work piece geometries) from knowledge based process planner and generates data driven animation in a distributed environment.
Nonlinear Random Responses of Shell Structures With Spatial Uncertainties
Authors: To C. W. S.
Published: June 2008

A novel procedure for large deformation nonstationary random response computation of shell structures with spatial uncertainty is presented. The procedure is free from the limitations associated with those employing perturbation approximation techniques, such as the so-called stochastic finite element method and probabilistic finite element method, for systems with spatial uncertainties. In addition, the procedure has several important and excellent features. Chief among these are: (a) ability to deal with large deformation problems of finite strain and finite rotation; (b) application of explicit linear and nonlinear element stiffness matrices, mass matrix, and load vectors reduces computation time drastically; (c) application of the averaged deterministic central difference scheme for the updating of co-ordinates and element matrices at every time step makes it extremely efficient compared with those employing the Monte Carlo simulation and the conventional central difference algorithm; and (d) application of the time co-ordinate transformation enables one to study highly stiff structural systems.
Handling Tool Holder Collision in Optimal Tool Sequence Selection for 2.5-D Pocket Machining
Authors: D’Souza Roshan M. , Wright Paul K. , Se´quin Carlo
Published: June 2008

Significant cycle time saving can be achieved in 2.5-D milling by intelligently selecting tool sequences. The problem of finding the optimal tool sequence was reduced to finding the shortest path in a single-source single-sink directed acyclic graph. The nodes in the graph represented the state of the stock after the tool named in the node was done machining and the edges represented the cost of machining. In this paper a novel method for handling tool holder collision in the graph-based algorithm for optimal tool sequence selection has been developed. The method consists of iteratively solving the graph for the shortest path, validating the solution by checking for tool holder collisions and eliminating problematic edges in the graph. Also described is a method to intelligently build the graph such that in presence of tool holder collisions, the complexity of building the graph is greatly reduced.
3D “Micro’’-Geometry Modeling From Image Cues
Authors: Wang Yu , Wang Charlie C. L. , Yuen Matthew M. F.
Published: June 2008

This paper presents an approach to construct 3D microstructure of a surface from a single image. By integrating our technique with traditional CAD tools, the surface modeling results have clear ‘micro’ surface structures. Firstly, a multi-pyramid image segmentation algorithm is applied on the single image to extract the objective region. Our segmentation algorithm is an energy-based model, and it is accelerated by multi-pyramid. In the following, we use a modified shape from shading (SFS) model to construct the 3D surface described in the extracted image region. Our method is a global SFS approach, which is based on a new energy function that represents the shading difference between the reconstructed image (obtained from the constructed 3D object) and the input image.
Local Polygon Reduction for Voxel-Based Modeling
Authors: Yim Soonkyu , Gea Hae Chang
Published: June 2008

In voxel-based modeling systems, shapes of objects are visualized in terms of many tiny polygons. Because these excessive polygons deteriorate the interactive visualization performance, a grid-dependent local polygon reduction method is developed in this paper. Instead of processing the entire polygons altogether in the reduction process, these polygons are divided into many subgroups and reduced separately. This method has the advantages of having faster computational speed and providing local editing functions. The relations of native voxel data and sub-regions for local reduction are discussed. The partial surface editing function is also presented.
Dynamic Shape Typing
Authors: Vergeest Joris S. M. , Wang Chensheng , Song Yu , Horva´th Imre
Published: June 2008

Automatic processing of shape information requires the selection of a representation form of shape. Shape modeling is based on a choice of shape type, which is the joint specification of representation form and a set of operations. In shape applications, such as shape design and shape optimization, it is not sufficient to maintain a static shape type. Depending on the specific needs during the application, i.e. depending on the modeling context, the appropriate shape type might be continuously varying. Programmed systems can handle static shape types relatively well. However, to support dynamic shape typing a number of fundamental problems need to be understood and solved. An approach to dynamic typing of freeform shapes is presented. Theoretical issues will be described and some concrete examples and initial experimental results will be presented.
Estimation of the Non-Linear Material Properties for a Finite Elements Model of the Human Body Parts Involved in Sitting
Authors: Moes Niels C. C. M. , Horva´th Imre
Published: June 2008

An optimization procedure was developed to search for the ergonomically optimum shape of consumer products. The entity to be optimized is a Finite Elements Model of the human body. The modification variable is the pressure values in the contact area. The Finite Elements Model and the optimization procedures were developed for a sitting support without backrest or arm rests. The model consists of a simplified assembly of the upper leg and the buttock area. Three components are included: skin, bony parts and in between a matrix of soft tissue. This paper presents the construction of the Finite Elements Model, in particular the assessment of the material properties according to the James-Green-Simpson elasticity model, and the first results of the Finite Elements Analysis. The first experiments are to validate the model for material properties. To that end the coefficients of the elasticity model are needed that cause good agreement of the maximum pressure values in the contact area with the predicted values obtained by earlier published regression. A hypothetical dependency of the maximum interface pressure on the stiffness is introduced. The results confirmed a part of the hypothesis. The current model needs further elaboration to test the hypothesis completely and to obtain a valid assessment of the material properties.
Computer-Aided Fixture Design Verification: Part 1 — The Framework and Modeling
Authors: Kang Y. , Rong Y. , Yang J. A.
Published: June 2008

Computer-aided fixture design (CAFD) techniques have been advanced rapidly that fixture configurations can be generated automatically, for both modular fixtures and dedicated fixtures. Computer-aided fixture design verification (CAFDV) is the technique for verifying and improving existing fixture designs. In this paper, the framework of CAFDV is introduced with two based on two models, geometric and kinematic models. The fixturing tolerance and stability verification will be presented in separated papers.
Empirical Studies for Evaluation and Investigation of a New Knowledge Representation Structure in Design Automation
Authors: Summers Joshua D. , Shah Jami J.
Published: June 2008

The introduction of a new knowledge representation structure, the design exemplar, in design automation systems dictates the need for developing a set of evaluative and investigative measures. Current research trends have focused on offering implemented systems as validations of new structures or using algorithmic and runtime complexity measures as evaluations. A set of objective and quantitative measures are introduced for evaluating the design exemplar. Based upon these measures, a series of empirical studies are executed that preliminarily demonstrate the breadth and depth of the potential for using the design exemplar as a knowledge representation structure. These measures may also be used as the basis for conducting other studies to evaluate independently multiple representation structures in design automation.
An Intelligent Manufacturing Advisor for Casting and Injection-Moulding Based on a Mid-Surface Approach
Authors: Lockett Helen L. , Guenov Marin D.
Published: June 2008

Products that are manufactured using near net-shape manufacturing processes must be designed with regard to the constraints of the manufacturing process. The purpose of this research project is to develop a knowledge based manufacturing advisor to assist designers of products for casting and injection moulding. The manufacturing advisor is tightly integrated with a CAD solid modeller, and uses a novel feature recognition approach to identify the manufacturing features of the part. A mid-surface abstraction from the part’s solid geometry is used as the basis for feature recognition, and it is argued that this is a better approach to feature recognition for this class of parts than a CAD solid model. Initial testing indicates that the feature recognition process is able to effectively recognise a range of features but that the quality of the feature recognition is dependent on the mid-surface representation that is generated.
A Collaborative Architecture for Multiple Computer Aided Engineering Applications
Authors: Cramer David , Jayaram Uma , Jayaram Sankar
Published: June 2008

In this paper, we describe the need, design, and implementation of a Collaborative Architecture. The Collaboration Architecture addresses the need for multiple Computer Aided Engineering applications to exchange data packets directly with each other in an effort to decrease the design cycle time. This architecture incorporates three components in its design, a server, a controller, and multiple members. The members generate and use the data packets. The server maintains and distributes the data packets between the members. The controller component determines which CAE users are generating or using which data sets. The member component has been implemented with three subcomponents, a pusher application, a receiver application, and the CAE application which uses / generates the data packets. For the local member communication, the Collaborative Architecture uses shared memory. For inter-component communication, the architecture uses CORBA. Finally, this paper describes the implementation of two Computer Aided Applications, Dv/Mockup and an Immersive Virtual Design Environment.
Metamodels for Planar 3R Workspace Optimization
Authors: Turner Cameron J.
Published: June 2008

Robotic workspace optimization is a central element of robot system design. To formulate the optimization problem, the complex relationships between design variables, tuning parameters, and performance indices need to be accurately and efficiently represented. The nature of the relationships suggests that metamodels, or models of the models, should be used to derive suitable objective functions. A comparison of two metamodeling techniques for robotic workspace optimization problems for several trial cases suggests that non-uniform rational B-spline models, derived from computer graphics and computer-aided design techniques, are as suitable as response surface models to solve planar 3R workspace optimization problems. Promising nonlinear modeling results with B-spline models suggest future work is justified and performance gains can be realized.
Distributed Control of a Track Based Multi-Head Robot
Authors: Derby Stephen J. , Brown David
Published: June 2008

A novel closed loop track based multi-head robot has been developed to increase material handing throughput. This robot allows for waves of autonomous robot heads to move materials in the working path by eliminating the traditional return path. Distributed control architecture was developed using a system comprising of desktop, embedded and single board PC’s, some linked by infrared communications. This paper discusses the design and impact of such a control architecture, and looks at some performance boundaries.
Performance Analysis for Design of a High-Precision Electronic Opto-Mechanical System for Vehicle Delineation Detection on Highway
Authors: Wang Zhaoqing , Chen Bo , Cheng Harry H. , Shaw Ben , Palen Joe
Published: June 2008

We have developed a laser photodiode array based detection system that can non-intrusively detect delineations of vehicles on the highway. A patent for this detection system has been recently approved by the U.S. Patent Office. The system is built with low-cost off-the-shelf opto-mechanical components. The error sources from a system design point of view will be analyzed in this paper. Our study indicates that the frequency of pulsed laser diodes, computer sampling rates, deviations in the angle of laser light and imperfectly matched detection points for sensor pairs are the main sources of error in the detection system.