An Evaluation of Cutting Edge and Machinability of Inclined Planetary Motion Milling for Difficult-to-cut Materials

AbstractRecently, the applications of difficult-to-cut materials (e.g. CFRP and titanium alloy) are increasing in the aviation and automotive industries. Conventional drilling tools occur burr and/or delamination on their materials. The inclined planetary motion milling consists of two independent spindle motions which are tool rotation and revolution. Eccentricity of the tool rotation axis is realized by inclination of few degrees from revolution axis. The movement of eccentric mechanism can be reduced by comparison with that of the orbital drilling. The inclined planetary motion milling reduces inertial vibration and decreases cutting force. According to the geometrical cutting principle, it can be decreased delamination and burr of their materials, comparing to orbital drilling. In the study, the authors revaluated optimum cutting condition for titanium alloy by use of the experimental design and carried out its repeatability test. And the authors developed on measurement and evaluation method for cutting edge profiles and examined the comprehensive discussion of the relationship among change to cutting edge wear and surface texture and circularity on drilling hole, tool rotation torque after based on the practical drilling experiments

Mass transfer control in multilayer EBC systems at high temperatures

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Stacked square microstrip antenna with a shorting post for dual band operation in WLAN applications

A small and wideband antenna for dual band (2.4/5.2 GHz bands) operation is presented. The proposed antenna has a shorting post and slits to miniaturize the size of patch. The bandwidth in the low frequency band (the 2.4 GHz band) increases as the length of the shorting post between the upper and lower patches increases. The lengths of the square patch of the proposed antenna are around 0.10lambda2.45GHz and 0.21lambda5.25GHz. The bandwidths are 5.2% and 11.0% in the 2.4G Hz and 5.2 GHz bands, respectively.2006 Asia-Pacific Microwave Conference : Yokohama, Japan, 2006.12.12-2006.12.1

Residual stress measurement of YB silicates by Raman Spectroscopy: First-principles and experimental studies

Components of next-generation gas turbines made from lightweight SiC-based ceramics need environmental barrier coatings (EBCs) to protect from water vapor at high temperature because Si-based ceramics vaporize in such environments. Yb silicates Yb2SiO5 and Yb2Si2O7 are promising EBC materials. In EBCs, residual stresses develop during thermal cycling due to mismatch between the thermal expansion coefficients of the silicate and the underlying ceramics, resulting in critical fatigue of the coating structure [1]. Raman microscopy is one method for measuring stress distributions in coating materials and has the potential to be used for diagnosing EBCs. Its suitability for analyzing stress states of Yb silicates has been unknown. In this study, we examine Raman spectra of Yb2SiO5, and Yb2Si2O7 under hydrostatic pressure based on first-principles calculations based on the density functional theory and we also examine the spectra of Yb2Si2O7 under uniaxial compressive stress in experiments using polycrystalline samples. When no external pressures applied, good agreement between calculated and experimental spectra is obtained as shown in Figure 1. The differences in the spectra between the silicates demonstrate the utility of using Raman microscopy to detect compositional changes in Yb-silicate coatings. From the calculations, lattice vibrations associated with a Raman peak are identified as exemplified by the characteristic mode of Si2O7 units in Yb2Si2O7 shown in figure 1(a). Please click Additional Files below to see the full abstract

Tissue Characterization of Coronary Plaque by Using Fractal Analysis-based Features of IVUS RF-signal

We propose a precise tissue characterization method of coronary plaque by using fractal analysis-based features which are obtained from radiofrequency (RF) signal employing intravascular ultrasound (IVUS) method. The IVUS method is used for the diagnosis of the acute coronary syndromes (ACS). In the proposed method, the fact that the RF signal reflects the complexity of the structure of tissue is used. The effectiveness of the proposed method is verified through a series of experiments by using IVUS RF signals obtained from a rabbit and a human patient

Theory of Josephson current on a lattice model of grain boundary in dd-wave superconductors

Identifying the origins of suppression of the critical current at grain boundaries of high-critical-temperature superconductors, such as cuprates and iron-based superconductors, is a crucial issue to be solved for future applications with polycrystalline materials. Although the dominant factor of current suppression might arise during material fabrication and/or processing, investigating it due to an internal phase change of the pair potential is an important issue in understanding the threshold of the critical current. In this paper, we study the Josephson current on a symmetric [001]-tilt grain boundary (GB) of a $d$-wave superconductor on a lattice model. In addition to the suppression of the maximum Josephson current associated with the internal phase change of the $d$-wave pair potential which has been predicted in continuum models, we find a unique phase interference effect due to folding of the Fermi surface in the lattice model. In particular, the resultant maximum Josephson current at low-tilting-angle regions tends to be suppressed more than that in preexisting theories. Because similar suppressions of the critical current at GBs have been reported in several experimental works, the present model can serve as a guide to clarify the complicated transport mechanism in GBs

Synergistic defect in 60S ribosomal subunit assembly caused by a mutation of Rrs1p, a ribosomal protein L11-binding protein, and 3′-extension of 5S rRNA in Saccharomyces cerevisiae

Rrs1p, a ribosomal protein L11-binding protein, has an essential role in biogenesis of 60S ribosomal subunits. We obtained conditionally synthetic lethal allele with the rrs1-5 mutation and determined that the mutation is in REX1, which encodes an exonuclease. The highly conserved leucine at 305 was substituted with tryptophan in rex1-1. The rex1-1 allele resulted in 3′-extended 5S rRNA. Polysome analysis revealed that rex1-1 and rrs1-5 caused a synergistic defect in the assembly of 60S ribosomal subunits. In vivo and in vitro binding assays indicate that Rrs1p interacts with the ribosomal protein L5–5S rRNA complex. The rrs1-5 mutation weakens the interaction between Rrs1p with both L5 and L11. These data suggest that the assembly of L5–5S rRNA on 60S ribosomal subunits coordinates with assembly of L11 via Rrs1p

Electric currents distributions on finite patch conductor of microstrip antenna

The electric currents on the upper, lower and side surfaces of the finite patchconductor of a circular microstrip antenna are calculated by using the methodof moment in the spectral domain. The electric current on the lower surfaceis much bigger than that on the upper surface and the input impedance ofmicrostrip antenna depends on the electric current on the lower surface.2003 Asia Pacific Microwave Conference, November 4-7, 2003, Sheraton Walkerhill Hotel, Seoul, Kore