The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Robert F. Handschuh - One of the best experts on this subject based on the ideXlab platform.
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modified involute helical gears computerized design simulation of meshing and stress analysis
Computer Methods in Applied Mechanics and Engineering, 2003Co-Authors: Faydor L. Litvin, Alfonso Fuentes, Luca Carvenali, Ignacio Gonzalezperez, Kazumasa Kawasaki, Robert F. HandschuhAbstract:The contents of the paper cover: (i) computerized design, (ii) methods for generation, (iii) simulation of meshing, and (iv) enhanced stress analysis of modified involute helical gears. The approaches proposed for modification of conventional involute helical gears are based on conjugation of double-crowned pinion with a conventional helical involute gear. Double-crowning of the pinion means deviation of cross-profile from an involute one and deviation in longitudinal direction from a helicoid surface. The pinion-gear tooth surfaces are in point contact, the bearing contact is localized and oriented longitudinally, edge contact is avoided, the influence of errors of alignment on the shift of bearing contact and vibration and noise are reduced substantially. The developed theory is illustrated with numerical examples that confirm the advantages of the gear drives of the modified geometry in comparison with conventional helical involute gears.
Anders Tunlid - One of the best experts on this subject based on the ideXlab platform.
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multiple gene genealogies and species recognition in the ectomycorrhizal fungus paxillus involutus
Fungal Biology, 2008Co-Authors: Jenny Hedh, Susanne Erland, Peter Samson, Anders TunlidAbstract:Paxillus involutus (basidiomycetes, Boletales) is a common ectomycorrhizal fungus in the Northern Hemisphere. The fungus displays significant variation in phenotypic characters related to morphology, physiology, and ecology. Previous studies have shown that P. involutus contains several intersterility groups and morphological species. In this study, we have used concordance of multiple gene genealogies to identify genetically isolated species of P. involutus. Fragments from five protein coding genes in 50 isolates of P. involutus collected from different hosts and environments in Europe and one location in Canada were analysed using phylogenetic methods. Concordance of the five gene genealogies showed that P. involutus comprises at least four distinct phylogenetic lineages: phylogenetic species I (with nine isolates), II (33 isolates), III (three isolates), and IV (five isolates). The branches separating the four species were long and well supported compared with the species internodes. A low level of shared polymorphisms was observed among the four lineages indicating a long time since the genetic isolation began. Three of the phylospecies corresponded to earlier identified morphological species: I to P. obscurosporus, II to P. involutus s. str., and III to P. validus. The phylogenetic species had an overlapping geographical distribution. Species I and II differed partly in habitat and host preferences.
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size and complexity of the nuclear genome of the ectomycorrhizal fungus paxillus involutus
Fungal Genetics and Biology, 2002Co-Authors: Antoine Le Quere, Tomas Johansson, Anders TunlidAbstract:The basidiomycete Paxillus involutus is forming ectomycorrhizal symbiosis with a broad range of forest trees. Reassociation kinetics on P. involutus nuclear DNA indicated a haploid genome size of 23Mb including 11% of repetitive DNA. A similar genome size (20Mb) was estimated by genomic reconstruction analysis using three single copy genes. To assess the gene density in the P. involutus genome, a cosmid containing a 33-kb fragment of genomic DNA was sequenced and used to identify putative open reading frames (ORFs). Twelve potential ORFs were predicted, eight displayed significant sequence similarities to known proteins found in other organisms and notably, several homologues to the Podospora anserina vegetative incompatibility protein (HetE1) were found. By extrapolation, we estimate the total number of genes in the P. involutus haploid genome to approximately 7700. (Less)
Faydor L. Litvin - One of the best experts on this subject based on the ideXlab platform.
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modified involute helical gears computerized design simulation of meshing and stress analysis
Computer Methods in Applied Mechanics and Engineering, 2003Co-Authors: Faydor L. Litvin, Alfonso Fuentes, Luca Carvenali, Ignacio Gonzalezperez, Kazumasa Kawasaki, Robert F. HandschuhAbstract:The contents of the paper cover: (i) computerized design, (ii) methods for generation, (iii) simulation of meshing, and (iv) enhanced stress analysis of modified involute helical gears. The approaches proposed for modification of conventional involute helical gears are based on conjugation of double-crowned pinion with a conventional helical involute gear. Double-crowning of the pinion means deviation of cross-profile from an involute one and deviation in longitudinal direction from a helicoid surface. The pinion-gear tooth surfaces are in point contact, the bearing contact is localized and oriented longitudinally, edge contact is avoided, the influence of errors of alignment on the shift of bearing contact and vibration and noise are reduced substantially. The developed theory is illustrated with numerical examples that confirm the advantages of the gear drives of the modified geometry in comparison with conventional helical involute gears.
Zhenquan Liu - One of the best experts on this subject based on the ideXlab platform.
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scroll profiles in scroll compressors general criteria and error sensitivity
International Journal of Refrigeration-revue Internationale Du Froid, 2013Co-Authors: Jianguo Qiang, Zhenquan LiuAbstract:Abstract General criteria for scroll profiles that include the evolute, orbiting movement, differential, and integrative conditions are proposed. The profile error sensitivity is defined based on the composite meshing error and meshing clearances of the scroll profiles. A case study on regular polygon Involutes as scroll profiles indicates that the general criteria are satisfied when the edge number of the two Involutes of a regular polygon is equal to the common multiple of the doubled number of scroll wraps on one scroll. The profile error sensitivity of the Involutes of a base circle is shown to be controlled by the radial machining error, which is extremely low. The involute of a base circle is the ideal profile for a scroll compressor because it contains low error sensitivity and more stable dynamic characteristics.
Kazumasa Kawasaki - One of the best experts on this subject based on the ideXlab platform.
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modified involute helical gears computerized design simulation of meshing and stress analysis
Computer Methods in Applied Mechanics and Engineering, 2003Co-Authors: Faydor L. Litvin, Alfonso Fuentes, Luca Carvenali, Ignacio Gonzalezperez, Kazumasa Kawasaki, Robert F. HandschuhAbstract:The contents of the paper cover: (i) computerized design, (ii) methods for generation, (iii) simulation of meshing, and (iv) enhanced stress analysis of modified involute helical gears. The approaches proposed for modification of conventional involute helical gears are based on conjugation of double-crowned pinion with a conventional helical involute gear. Double-crowning of the pinion means deviation of cross-profile from an involute one and deviation in longitudinal direction from a helicoid surface. The pinion-gear tooth surfaces are in point contact, the bearing contact is localized and oriented longitudinally, edge contact is avoided, the influence of errors of alignment on the shift of bearing contact and vibration and noise are reduced substantially. The developed theory is illustrated with numerical examples that confirm the advantages of the gear drives of the modified geometry in comparison with conventional helical involute gears.
