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Search Results: 1 - 10 of 1213 matches for " Shinichi Morita "
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A Micromixer Using the Chaos of Secondary Flow: Rotation Effect of Channel on the Chaos of Secondary Flow  [PDF]
Yasutaka Hayamizu, Shinichiro Yanase, Shinichi Morita, Shigeru Ohtsuka, Takeshi Gonda, Kazunori Nishida, Kyoji Yamamoto
Open Journal of Fluid Dynamics (OJFD) , 2012, DOI: 10.4236/ojfd.2012.24A021
Abstract: The micromixer, which has a rotor with a curved channel, is studied experimentally. The secondary flow in a curved channel of rectangular cross-section is investigated using PIV (Particle Image Velocimetry) and LIF (Laser Induced Fluorescence) methods. Two walls of the channel (the inner and top walls) rotate around the center of curvature and a pressure gradient is imposed in the direction of the exit of the channel. The non-dimensional channel curvature δ=a/R is taken to be about 0.1, where 2a is the width of the channel, R the curvature radius of the channel. Other non-dimensional parameters concerned are the Dean number De=Reδ1/2, the Reynolds number Re=qdh/v, where q is the mean flow velocity in the channel axis direction, ν the kinematic viscosity, dh the hydraulic diameter of the channel, and the Taylor number Tr=2(2δ)1/2Ωa2/(δv), where Ω is the angular velocity of the rotor. Photographs of the flow in a cross-section at 180° downstream from the curved channel entrance are taken by changing the flux (De) at a constant rotational speed (Tr) of the channel walls. It is found that good mixing performance is obtained in the case of De≤0.1|Tr| and for that case secondary flows show chaotic behaviors. And then we have confirmed the occurrence of reversal of the mean axial flow.
Behavior of Motile Sperm in Taylor-Couette Flow: Effect of Shear Stress on the Behavior of Motile Sperm  [PDF]
Yasutaka Hayamizu, Toru Hyakutake, Koji Matsuura, Shinichiro Yanase, Shinichi Morita, Shigeru Ohtsuka, Takeshi Gonda
Open Journal of Fluid Dynamics (OJFD) , 2013, DOI: 10.4236/ojfd.2013.32A002
Abstract:

Infertility is often cited as one of the causes of a declining birthrate, which has become a serious social problem in recent years. Processes by which motile sperm can be safely and easily sorted are therefore important for infertility treatment. Therefore, as a new sorting method, microfluidic sperm sorter using the microfluidic system has been developed. To improve more separation efficiency of this device, it is necessary to know the behaviors of motile sperm in the microchannel where the sperm undergo shear flow. The previous study implied the necessity of the modeling of motile sperm in the shear flow. In the present study, therefore, we experimentally investigated the behavior of the motile sperm in the Taylor-Couette flow using PTV (Particle Tracking Velocimetry) method. The experimental results showed that the ascent of the shear stress led to the increase in the sperm velocity, and the direction of the sperm velocity was opposite to that of the flow.

A Micromixer Using the Taylor-Dean Flow: Effect of Inflow Conditions on the Mixing  [PDF]
Toshihiko Kawabe, Yasutaka Hayamizu, Shinichiro Yanase, Takeshi Gonda, Shinichi Morita, Shigeru Ohtsuka, Kyoji Yamamoto
Open Journal of Fluid Dynamics (OJFD) , 2014, DOI: 10.4236/ojfd.2014.45037
Abstract: Chaotic mixing in a curved-square channel flow is studied experimentally and numerically. Two walls of the channel (inner and top walls) rotate around the center of curvature and a pressure gradient is imposed in the direction toward the exit of the channel. This flow is a kind of Taylor-Dean flows. There are two parameters dominating the flow, the Dean number De (∝ the pressure gradient or the Reynolds number) and the Taylor number Tr (∝ the angular velocity of the wall rotation). In the present paper, we analyze the physical mechanism of chaotic mixing in the Taylor-Dean flow by comparing experimental and numerical results. We produced a micromixer model of the curved channel several centimeters long with square cross section of a few millimeters side. The secondary flow was measured using laser induced fluorescence (LIF) method to examine secondary flow characteristics. We also performed three-dimensional numerical simulations for the exactly same configuration as the experimental system to study the mechanism of chaotic mixing. It is found that good mixing performance is achieved for the case of De ≤ 0.1Tr, and that mixing efficiency changes according to the difference in inflow conditions. The flow is studied both experimentally and numerically, and both results agree with each other very well.
A Micromixer Using the Taylor-Dean Flow: Effects of Aspect Ratio and Inflow Condition on the Mixing  [PDF]
Yasutaka Hayamizu, Toshihiko Kawabe, Shinichiro Yanase, Takeshi Gonda, Shinichi Morita, Shigeru Ohtsuka, Kyoji Yamamoto
Open Journal of Fluid Dynamics (OJFD) , 2015, DOI: 10.4236/ojfd.2015.53027
Abstract: Chaotic mixing in three different types of curved-rectangular channels flow has been studied experimentally and numerically. Two walls of the channel (inner and top walls) rotate around the center of curvature and a pressure gradient are imposed in the direction toward the exit of the channel. This flow is a kind of Taylor-Dean flow. There are two parameters dominating the flow, the Dean number De (∝ the pressure gradient or the Reynolds number) and the Taylor number Tr (∝ the angular velocity of the wall rotation). In this paper, we analyze the physical mechanism of chaotic mixing in the Taylor-Dean flow by comparing experimental results and numerical ones. We produced three micromixer models of the curved channel, several centimeters long, with rectangular cross-section of a few millimeters side. The secondary flow is measured using laser induced fluorescence (LIF) method to examine secondary flow characteristics. Also we performed three-dimensional numerical simulations with the open source CFD solver, OpenFOAM, for the same configuration as the experimental system to study the mechanism of chaotic mixing. It is found that good mixing performance is obtained in the case of De ≤ 0.1 Tr, and it becomes more remarkable when the aspect ratio tends to large. And it is found that the mixing efficiency changes according to the aspect ratio and inflow condition.
Arterial embolization in patients with grade-4 blunt renal trauma: evaluation of the glomerular filtration rates by dynamic scintigraphy with 99mTechnetium-diethylene triamine pentacetic acid
Seiji Morita, Sadaki Inokuchi, Tomoatsu Tsuji, Tomokazu Fukushima, Shigeo Higami, Takeshi Yamagiwa, Iizuka Shinichi
Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine , 2010, DOI: 10.1186/1757-7241-18-11
Abstract: We performed AE in 17 patients with grade-4 blunt renal trauma and determined their serum creatinine (sCr) level and glomerular filtration rate (GFR; estimated by dynamic scintigraphy) after 3 months. In 4 patients with low GFR of the injured kidney (<20 ml·min-1·1.73 m-2), the GFR and sCr were measured again at 6 months. Data are presented as median and interquartile range (25th, 75th percentile).The median GFR of the injured kidney, total GFR, and median sCr at 3 months were 29.3 (23.7, 35.3) and 96.8 (79.1, 102.6) ml·min-1·1.73 m-2 and 0.6 (0.5, 0.7) mg/dl, respectively. In the patients with low GFR (ml·min-1·1.73 m-2), the median GFR of the injured kidney, total GFR, and median sCr (mg/dl) were 16.2 (15.7, 16.3), 68.7 (61.1, 71.6), and 0.7 (0.7, 0.9), respectively, at 3 months and 34.5 (29.2, 37.0), 90.9 (79.1, 98.8), and 0.7 (0.7, 0.8), respectively, at 6 months.The function of the injured kidney was preserved in all patients, indicating the efficacy of AE for the treatment of grade-4 blunt renal trauma.Some recent studies have suggested that high-grade renal trauma can be successfully treated by non-operative management (NOM), which includes conservative management and arterial embolization (AE) [1-4]. In these studies, it was emphasized that NOM for high-grade renal trauma is less invasive than nephrectomy, and unlike nephrectomy, it preserves the renal function of the injured kidney. In most of these studies, renal function was assessed on the basis of the serum creatinine (sCr) level; serum blood urea nitrogen (BUN) level; and creatinine clearance (CCr24 h), which was determined from a 24-h urine sample. These parameters do not reflect the function of the injured kidney, but the total renal function (i.e., the function of both the injured and the contralateral uninjured kidney). Dynamic scintigraphy can determine the differential renal function.We hypothesized that AE for severe blunt renal trauma could preserve the renal function of the injured kidney. The
The Relationship among Cost-Reducing R&D Investment, Occupational Choice, and Trade  [PDF]
Tadashi Morita
Theoretical Economics Letters (TEL) , 2014, DOI: 10.4236/tel.2014.49111
Abstract: In this paper, I construct a two-country model in which oligopolistic firms export goods and undertake cost-reducing R&D investment. In this model, abilities of individual to become skilled worker are heterogeneous and they choose to become skilled worker or unskilled worker. Individuals have to incur the cost of education in order to become skilled workers. Each country imposes tariffs. When the cost of education is sufficiently high, a decrease in the tariff rate decreases the level of R&D investment. However, when the cost of education is sufficiently small, a decrease in the tariff rate increases the level of R&D investment.
Einstein Dilemma and Two-State Vector Formalism  [PDF]
Kunihisa Morita
Journal of Quantum Information Science (JQIS) , 2015, DOI: 10.4236/jqis.2015.52006
Abstract: In the famous EPR paper published in 1935, Einstein, Podolsky, and Rosen suggested a thought experiment, which later became known as the “EPR experiment”. Using the EPR experiment, they posited that quantum mechanics was incomplete. Einstein, however, was dissatisfied with the EPR paper and published a second work on the EPR experiment, in which he discussed the dilemma of choosing whether quantum mechanics was incomplete or nonlocal. Currently, most physicists choose the nonlocality of quantum mechanics over Einstein’s choice of the incompleteness of quantum mechanics. However, with an appropriate alternate hypothesis, both of these choices can be rejected. Herein, I demonstrate an approach to overcome the Einstein Dilemma by proposing a new interpretation invoked by a new formalism of quantum mechanics known as two-state vector formalism.
Measurement Problem and Two-State Vector Formalism  [PDF]
Kunihisa Morita
Journal of Modern Physics (JMP) , 2015, DOI: 10.4236/jmp.2015.613191
Abstract: In this paper, I show that an interpretation of quantum mechanics using two-state vector formalism proposed by Aharonov, Bergmann, and Lebowitz, can solve one of the measurement problems formulated by Maudlin. According to this interpretation, we can simultaneously insist that the wave function of a system is complete, that the wave function is determined by the Schr?dinger equation, and that the measurement of a physical quantity always has determinate outcomes, although Maudlin in his formulation of the measurement problem states that these three claims are mutually inconsistent. Further, I show that my interpretation does not contradict the uncertainty relation and the no-go theorem.
Intuitive Concept or Physical Meaning of Lagrangian  [PDF]
Susumu Morita
World Journal of Mechanics (WJM) , 2016, DOI: 10.4236/wjm.2016.63007
Abstract: The authors have been studying on the principle of motion generation behind animals, mainly human, and have reached a certain milestone with it in [1]. Because [1] ended up being very interdisciplinary, the author has been looking for an opportunity to close in on the part where we have grasped the conceptual idea of a Lagrangian. This paper proposes the physical meaning or its intuitive concept of a Lagrangian. This is a daring attempt because the topic is over 240 years of enigma, whereby so many have neglected of its absence, and physics has gone further towards its frontiers of their time, and has successfully flourished. Meanwhile, Lagrangian is not getting enough of teachers’ attention on students getting stuck on this function, despite the fact that it is a strong foundation as is only the beginning towards Hamiltonian formalism, general relativity, and modern physics of today. This paper’s sole motive is to answer what the title says in detail, helping each and everyone who faces Lagrangian for their first time. The paper is positioned to be a supplement for [1]. This literature had three topics bound into one. Out of the three, this document focuses in the part of the intuitive meaning of Lagrangian, since the paper had contents related to multiple disciplines. The author finds it worthy to discuss this topic in an independent, more detailed manner.
Non-Neutral Technological Progress and Income Distribution—Piketty’s Fundamental Laws in a Neoclassical Two-Sector Model  [PDF]
Masanori Morita
Theoretical Economics Letters (TEL) , 2016, DOI: 10.4236/tel.2016.66119
Abstract: This paper discusses the theoretical validity of Thomas Piketty’s fundamental laws about income distribution in the context of a standard neoclassical growth model. We take Uzawa’s two-sector growth model as the platform of our analysis, as it allows us to make a distinction between the technological elasticity of factor substitution of the production function and the aggregate distributive elasticity of substitution. We examine the properties of the non-steady growth path through both analytical and numerical investigations. We conclude that some of the numerical simulations corroborate Piketty’s theory without assuming that the economy is on a steady growth path. However, if the elasticities of factor substitution in the individual sectors are less than one as many empirical studies show, then the economy approaches the state where all products are completely distributed to workers. This contradicts Piketty’s diagnosis about the current distributional inequality. In addition, the aggregate income distribution is stable for a relatively long time, and differences in the initial conditions are preserved during this period. This means that the comparative statics of the steady states might not present an adequate description of the economy’s behavior in a period of time that is practical. Our final evaluation of Piketty’s proposition is that it is better understood as a theory inferred from historical data and not one necessarily deduced from standard neoclassical growth theory.
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