Effect of crowning radius on rolling contact fatigue strength for traction drive elements

A simulation of the rolling contact fatigue strength of a traction drive element was developed. This simulation accounts for both the distribution of sizes of inclusions in the element material and the influence of traction forces at the element surface. The shear strength of the matrix structure surrounding an inclusion was estimated with an equation. The hardness distribution and the Weibull distribution of inclusion dimensions, which are necessary parameters to calculate the rolling contact fatigue strength, were determined by observation of an actual test specimen. The purpose of this report is simulations to evaluate the effect of the crowning radius on the rolling contact fatigue strength and the torque capacity. The simulations were carried out by varying the crowning radius of the virtual roller. To consider the effect of the crowning radius, a simulated two-dimensional virtual roller, which has actual material properties, was modified to a roller multilayered toward the axial direction. The simulation assuming the actual roller led to a difference of 1.0% from the experimental rolling contact fatigue strength. This difference was 2.4 points smaller than the result for the two-dimensional virtual roller. The rolling contact fatigue strength decreased with increasing crowning radius for two reasons. One was the increase in the number of inclusions under the high stress due to the increasing crowning radius. The other was the expansion of the portion of the roller subject to high stresses down to a depth having small hardness. However, the torque capacity calculated from the contact force resulting in failure increased with the increasing crowning radius

Development of Scroll Compressor for 16HP VRF System

Usage of multiple compressors is applied for general VRF system at more than 12HP capacity because it is difficult to keep capacity and performance by usage of one compressor for such large capacity system. But usage of multiple compressors has problem controlling cost and keeping oil level in each compressor. In this paper, new scroll compressor which can reduce oil circulation in refrigerant circuit, keep oil level in the compressor, keep high capacity and performance and operate in a wide running range and can be applied until 16HP capacity by usage of one compressor was developed. It is important to keep oil level in a compressor because VRF system has large refrigerant circuit. Analysis of oil and refrigerant flow in the compressor was applied and structure of preventing oil agitation was introduced to reduce oil circulation in refrigerant circuit and keep oil level. The compressor for VRF system is demanded to operate in a wide running range from low speed to high speed and from low load to high load. This compressor can supply oil even if rotational speed is low because this compressor supplies oil by differential pressure and can supply enough oil at low differential pressure by new structure of oil lubrication, therefore running range become wider. And analysis of lubrication between shaft and bearing was applied and this compressor can keep reliability against high load at large capacity by optimal structure

Origin of structural and kinematical properties of the Small Magellanic Cloud

We investigate structural, kinematical, and chemical properties of stars and gas in the Small Magellanic Cloud (SMC) interacting with the Large Magellanic Cloud (LMC) and the Galaxy based on a series of self-consistent chemodynamical simulations. We adopt a new "dwarf spheroidal model" in which the SMC initially has both old stars with a spherical spatial distribution and an extended HI gas disk. We mainly investigate SMC's evolution for the last 3 Gyr within which the Magellanic stream (MS) and the Magellanic bridge (MB) can be formed as a result of the LMC-SMC-Galaxy interaction. Our principal results, which can be tested against observations, are as follows. The final spatial distribution of the old stars projected onto the sky is spherical even after the strong LMC-SMC-Galaxy interaction, whereas that of the new ones is significantly flattened and appears to form a bar structure. Old stars have the line-of-sight velocity dispersion (sigma) of ~ 30 km/s and slow rotation with the maximum rotational velocity (V) of less than slow rotation with the maximum rotational velocity (V) of less than 20 km/s and show asymmetry in the radial profiles. New stars have a smaller sigma than old ones and a significant amount of rotation (V/sigma >1). HI gas shows velocity dispersions of sigma = 10-40 km/s a high maximum rotational velocity (V ~ 50 km/s), and the spatial distribution similar to that of new stars. The new stars with ages younger than 3 Gyr show a negative metallicity gradient in the sense that more metal-rich stars are located in the inner regions of the SMC.Comment: 21 pages, 21 figures (5 color), accepted by PAS

Genomic Analysis of Homotypic Vacuole Fusion

Yeast vacuoles undergo fission and homotypic fusion, yielding one to three vacuoles per cell at steady state. Defects in vacuole fusion result in vacuole fragmentation. We have screened 4828 yeast strains, each with a deletion of a nonessential gene, for vacuole morphology defects. Fragmented vacuoles were found in strains deleted for genes encoding known fusion catalysts as well as 19 enzymes of lipid metabolism, 4 SNAREs, 12 GTPases and GTPase effectors, 9 additional known vacuole protein-sorting genes, 16 protein kinases, 2 phosphatases, 11 cytoskeletal proteins, and 28 genes of unknown function. Vacuole fusion and vacuole protein sorting are catalyzed by distinct, but overlapping, sets of proteins. Novel pathways of vacuole priming and docking emerged from this deletion screen. These include ergosterol biosynthesis, phosphatidylinositol (4,5)-bisphosphate turnover, and signaling from Rho GTPases to actin remodeling. These pathways are supported by the sensitivity of the late stages of vacuole fusion to inhibitors of phospholipase C, calcium channels, and actin remodeling. Using databases of yeast protein interactions, we found that many nonessential genes identified in our deletion screen interact with essential genes that are directly involved in vacuole fusion. Our screen reveals regulatory pathways of vacuole docking and provides a genomic basis for studies of this reaction

Location of phosphorylation site and DNA-binding site of a positive regulator, OmpR, involved in activation of the osmoregulatory genes of Escherichia coli

AbstractThe OmpR protein of Escherichia coli is a positive regulator involved in activation of the ompF and ompC genes which encode the major outer membrane proteins OmpF and OmpC, respectively. By employing recombinant DNA techniques, we isolated the N- and C-terminal halves of the OmpR molecule. From the results of biochemical analyses of these fragments, it was concluded that the N-terminal portion contains a site involved in phosphorylation by an OmpR-specific protein kinase EnvZ, whereas the C-terminal part possesses a DNA-binding site for the ompC and ompF promoters

Synthesis of 8-deoxypumiliotoxin 193H and 9-deoxyhomopumiliotoxin 207O

The asymmetric synthesis of 8-deoxypumiliotoxin 193H and 9-deoxyhomopumiliotoxin 207O has been achieved, starting from both enantiomers of (+)- and (−)-10. Enantiomerically pure alcohols (+)- and (−)-10 were obtained by lipase-mediated kinetic resolution of racemic 10, which was prepared in 3 steps from new lactam-type building block (−)-8 in a highly stereoselective manner

シリョウ チョウカク ショウガイジ ノ リズム チカク ニカンスル ブンケンテキ コウサツ

本稿では､リズムの知覚過程を群化と拍節に分け､時間知覚とリズム知覚に関する知見を概観した｡そのことから､リズム知覚の過程を明らかにするうえで､音系列の群化と拍節知覚を統合したモデルの必要性をあげた｡また､聴覚障害児･者を対象とした従来のリズム知覚研究の方法論的問題を指摘し､彼らによるリズム知覚を詳細に検討するうえで､同期反応が有効な指標になることを述べた｡さらに､聴覚と他のモダリティの併用が聴覚障害児のリズム知覚の一助となる可能性を示し､そのことに関する研究の必要性をあげた