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Numerical Study of Blade-Vortex Interaction (BVI) Noise Capturing
Tanabe, Yasutada,Saito, Shigeru,Takasaki, Keisuke,Fujita, Hajime The Korean Society for Aeronautical and Space Scie 2008 International Journal of Aeronautical and Space Sc Vol.9 No.2
The noise is one of the serious problems concerning helicopters operations. The issue of helicopter external noise generated mainly from a helicopter rotor has always affected the use of rotorcrafts, especially in the urban environment. The noise sources depend on the flight configurations. In particular, a noise generated by the interaction between blades and tip vortices mainly occurs during descent flight. This noise is called blade-vortex interaction (BVI) noise, and this BVI noise is particularly penalizing for helicopters. In this paper, a numerical study to capture the BVI noise is carried out. The numerical study is performed in two phases. In the first phase, a 2D simulation based on parallel BYI event of Kitapliglu et al experiment is performed. In the second phase, 3D simulation based on HART Ⅱ experiment is performed. Several experimental data such as thrust, torque, blade sectional load, its derivative and vortex location are compared with calculation results and the comparison showed reasonably good agreement.
Kawasaki, Yasuhiro,Saito, Mitsuru,Won, Jonghwa,Bae, Jin Young,Sato, Hajime,Toyoda, Hiroki,Kuramoto, Eriko,Kogo, Mikihiko,Tanaka, Takuma,Kaneko, Takeshi,Oh, Seog Bae,Bae, Yong Chul,Kang, Youngnam Frontiers Media S.A. 2018 Frontiers in cellular neuroscience Vol.12 No.-
<P>Glutamatergic dendritic EPSPs evoked in cortical pyramidal neurons are depressed by activation of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels expressed in dendritic spines. This depression has been attributed to shunting effects of HCN current (<I>I</I><SUB>h</SUB>) on input resistance or <I>I</I><SUB>h</SUB> deactivation. Primary sensory neurons in the rat mesencephalic trigeminal nucleus (MTN) have the somata covered by spine-like microvilli that express HCN channels. In rat MTN neurons, we demonstrated that <I>I</I><SUB>h</SUB> enhancement apparently diminished the glutamate receptor (GluR) current (<I>I</I><SUB>GluR</SUB>) evoked by puff application of glutamate/AMPA and enhanced a transient outward current following <I>I</I><SUB>GluR</SUB> (OT-<I>I</I><SUB>GluR</SUB>). This suggests that some outward current opposes inward <I>I</I><SUB>GluR</SUB>. The <I>I</I><SUB>GluR</SUB> inhibition displayed a U-shaped voltage-dependence with a minimal inhibition around the resting membrane potential, suggesting that simple shunting effects or deactivation of <I>I</I><SUB>h</SUB> cannot explain the U-shaped voltage-dependence. Confocal imaging of Na<SUP>+</SUP> revealed that GluR activation caused an accumulation of Na<SUP>+</SUP> in the microvilli, which can cause a negative shift of the reversal potential for <I>I</I><SUB>h</SUB> (<I>E</I><SUB>h</SUB>). Taken together, it was suggested that <I>I</I><SUB>GluR</SUB> evoked in MTN neurons is opposed by a transient decrease or increase in standing inward or outward <I>I</I><SUB>h</SUB>, respectively, both of which can be caused by negative shifts of <I>E</I><SUB>h</SUB>, as consistent with the U-shaped voltage-dependence of the <I>I</I><SUB>GluR</SUB> inhibition and the OT-<I>I</I><SUB>GluR</SUB> generation. An electron-microscopic immunohistochemical study revealed the colocalization of HCN channels and glutamatergic synapses in microvilli of MTN neurons, which would provide a morphological basis for the functional interaction between HCN and GluR channels. Mathematical modeling eliminated the possibilities of the involvements of <I>I</I><SUB>h</SUB> deactivation and/or shunting effect and supported the negative shift of <I>E</I><SUB>h</SUB> which causes the U-shaped voltage-dependent inhibition of <I>I</I><SUB>GluR</SUB>.</P>
Numerical Study of Blade-Vortex Interaction (BVI) Noise Capturing
Yasutada Tanabe,Shigeru Saito,Keisuke Takasaki,Hajime Fujita 한국항공우주학회 2008 International Journal of Aeronautical and Space Sc Vol.9 No.2
The noise is one of the serious problems concerning helicopters operations. The issue of helicopter external noise generated mainly from a helicopter rotor has always affected the use of rotorcrafts, especially in the urban environment. The noise sources depend on the flight configurations. In particular, a noise generated by the interaction between blades and tip vortices mainly occurs during descent flight. This noise is called blade-vortex interaction (BVI) noise, and this BVI noise is particularly penalizing for helicopters. In this paper, a numerical study to capture the BVI noise is carried out. The numerical study is performed in two phases. In the first phase, a 2D simulation based on parallel BYI event of Kitapliglu et al experiment is performed. In the second phase, 3D simulation based on HART Ⅱ experiment is performed. Several experimental data such as thrust, torque, blade sectional load, its derivative and vortex location are compared with calculation results and the comparison showed reasonably good agreement.
Numerical Study of Blade-Vortex Interaction (BVI) Noise Capturing
Yasutada Tanabe,Shigeru Saito,Takasaki Keisuke,Hajime Fujita 한국항공우주학회 2008 한국항공우주학회 학술발표회 논문집 Vol.- No.-
The noise is one of the serious problems concerning helicopters operations. The issue of helicopter external noise generated mainly from a helicopter rotor has always affected the use of rotorcrafts, especially in the urban environment. the noise sources depend on the night configurations. In particular, a noise generated by the interaction between blades and tip vortices mainly occurs during descent night. This noise is called blade-vortex interaction (BVI) noise, and this BVI noise is particularly penalizing for helicopters. In this paper, a numerical study to capture the BVI noise is carried out. The numerical study is performed in two phases. In the first phase, a 2D simulation based on parallel BVI event of Kitapliglu et al experiment is performed. In the second phase, 3D simulation based on HART Ⅱ experiment is performed. Several experimental data such as thrust, torque, blade sectional load, its derivative and vortex location are compared with calculation results and the comparison showed reasonably good agreement.
A distinct functional distribution of α and γ motoneurons in the rat trigeminal motor nucleus
Morita-Isogai, Yukako,Sato, Hajime,Saito, Mitsuru,Kuramoto, Eriko,Yin, Dong Xu,Kaneko, Takeshi,Yamashiro, Takashi,Takada, Kenji,Oh, Seog Bae,Toyoda, Hiroki,Kang, Youngnam Springer-Verlag 2017 BRAIN STRUCTURE AND FUNCTION Vol.222 No.7
<P>Gamma-motoneurons (gamma MNs) play a crucial role in regulating isometric muscle contraction. The slow jaw-closing during mastication is one of the most functional isometric contractions, which is developed by the rank-order recruitment of alpha-motoneurons (alpha MNs) in a manner that reflects the size distribution of alpha MNs. In a mouse spinal motor nucleus, there are two populations of small and large MNs; the former was identified as a population of gamma MNs based on the positive expression of the transcription factor estrogen-related receptor 3 (Err3) and negative expression of the neuronal DNA-binding protein NeuN, and the latter as that of alpha MNs based on the opposite pattern of immunoreactivity. However, the differential identification of alpha MNs and gamma MNs in the trigeminal motor nucleus (TMN) remains an assumption based on the size of cell bodies that were retrogradely stained with HRP. We here examined the size distributions of alpha MNs and gamma MNs in the dorsolateral TMN (dl-TMN) by performing immunohistochemistry using anti-Err3 and anti-NeuN antibodies. The dl-TMN was identified by immunopositivity for vesicular glutamate transporter-1. Immunostaining for choline acetyltransferase and Err3/NeuN revealed that the dl-TMN is composed of 65% alpha MNs and 35% gamma MNs. The size distribution of alpha MNs was bimodal, while that of gamma MNs was almost the same as that of the population of small alpha MNs , suggesting the presence of alpha MNs as small as gamma MNs. Consistent with the size concept of motor units, the presence of smaller jaw-closing alpha MNs was coherent with the inclusion of jaw-closing muscle fibers with smaller diameters compared to limb muscle fibers.</P>
Hiroyuki Takamaru,Shigetaka Yoshinaga,Hajime Takisawa,Ichiro Oda,Hitoshi Katai,Shigeki Sekine,Kazuhiro Taniguchi,Yutaka Saito 거트앤리버 소화기연관학회협의회 2020 Gut and Liver Vol.14 No.5
Background/Aims: The accurate assessment of the depth of invasion of early gastric cancer (EGC) is critical to determine the most appropriate treatment option. However, it is difficult to distinguish shallow submucosal (SM1) invasion from deeper submucosal (SM2) invasion. We investigated the diagnostic performance of endoscopic ultrasonography (EUS) using a miniature probe for EGC with suspected SM invasion. Methods: From April 2008 to June 2018, EGCs with suspected SM invasion were analyzed retrospectively. The EGCs examined by a 20 MHz high-frequency miniature probe was included in our study. Esophago-gastric junction cancers and patients treated by chemotherapy before resection were excluded. The sensitivity and specificity for the detection of SM2 invasion by EUS were compared with those of white light imaging (WLI). Additionally, factors related to depth underestimation or overestimation were investigated using multivariate analysis. Results: A total of 278 EGCs in 259 patients were included in the final analysis. The sensitivity and specificity for SM2 or deeper by EUS were 73.7% (87/118) and 74.4% (119/160), respectively. The sensitivity and specificity by WLI were 47.5% (56/118) and 68.1% (109/160), respectively. The sensitivity of EUS was significantly superior to that of conventional endoscopy (p<0.01). Multivariate analysis revealed that an anterior location of the EGC was an independent risk factor for underestimation by EUS (odds ratio, 3.3; 95% confidence interval, 1.1 to 9.8; p=0.03). Conclusions: The depth diagnostic performance for EGCs with suspected SM invasion using EUS was satisfactory and superior to that of conventional endoscopy. Additionally, it is important to recognize factors that may lead to misdiagnosis in those lesions.