• Title/Summary/Keyword: corresponding principle

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A Wearable Watch-type Reflectance-based Blood-oxygen Saturation (SpO2) Level Estimation (반사광을 이용한 손목시계형 혈중산소포화도 (SpO2) 측정기)

  • Lee, Hooseok;Thap, Tharoeun;Lee, Jinseok
    • Annual Conference of KIPS
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    • 2015.10a
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    • pp.578-579
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    • 2015
  • Transmission and reflectance are two non-invasive techniques to perform pulse oximetry. This paper presents a design of reflectance-based pulse oximetry for watch-type wearable device, in which sensor and detector are located on the same surface of the body part. The basic principle of a pulse oximeter is based on the measurement of the red and infrared (IR) light absorption. Oxygenated blood has significant differences of light absorption characteristics than deoxygenated blood under red (660 nm) and infrared (940 nm) wavelength. Infrared is absorbed more by oxygenated hemoglobin than red. So the hardware implementation is included placing of the two LEDs (red and IR) with single photo-detector in the middle on the patient's wrist to get the corresponding pulsatile signals which are used to estimate the $SpO_2$.

Influence of porosity and axial preload on vibration behavior of rotating FG nanobeam

  • Ehyaei, Javad;Akbarshahi, Amir;Shafiei, Navvab
    • Advances in nano research
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    • v.5 no.2
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    • pp.141-169
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    • 2017
  • In this paper, a nanobeam connected to a rotating molecular hub is considered. The vibration behavior of rotating functionally graded nanobeam based on Eringen's nonlocal theory and Euler-Bernoulli beam model is investigated. Furthermore, axial preload and porosity effect is studied. It is supposed that the material attributes of the functionally graded porous nanobeam, varies continuously in the thickness direction according to the power law model considering the even distribution of porosities. Porosity at the nanoscopic length scale can affect on the rotating functionally graded nanobeams dynamics. The equations of motion and the associated boundary conditions are derived through the Hamilton's principle and generalized differential quadrature method (GDQM) is utilized to solve the equations. In this paper, the influences of some parameters such as functionally graded power (FG-index), porosity parameter, axial preload, nonlocal parameter and angular velocity on natural frequencies of rotating nanobeams with pure ceramic, pure metal and functionally graded materials are examined and some comparisons about the influence of various parameters on the natural frequencies corresponding to the simply-simply, simplyclamped, clamped-clamped boundary conditions are carried out.

Buckling and stability analysis of sandwich beams subjected to varying axial loads

  • Eltaher, Mohamed A.;Mohamed, Salwa A
    • Steel and Composite Structures
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    • v.34 no.2
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    • pp.241-260
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    • 2020
  • This article presented a comprehensive model to study static buckling stability and associated mode-shapes of higher shear deformation theories of sandwich laminated composite beam under the compression of varying axial load function. Four higher order shear deformation beam theories are considered in formulation and analysis. So, the model can consider the influence of both thick and thin beams without needing to shear correction factor. The compression force can be described through axial direction by uniform constant, linear and parabolic distribution functions. The Hamilton's principle is exploited to derive equilibrium governing equations of unified sandwich laminated beams. The governing equilibrium differential equations are transformed to algebraic system of equations by using numerical differential quadrature method (DQM). The system of equations is solved as an eigenvalue problem to get critical buckling loads and their corresponding mode-shapes. The stability of DQM in determining of buckling loads of sandwich structure is performed. The validation studies are achieved and the obtained results are matched with those. Parametric studies are presented to figure out effects of in-plane load type, sandwich thickness, fiber orientation and boundary conditions on buckling loads and mode-shapes. The present model is important in designing process of aircraft, naval structural components, and naval structural when non-uniform in-plane compressive loading is dominated.

Limit speeds and stresses in power law functionally graded rotating disks

  • Madan, Royal;Saha, Kashinath;Bhowmick, Shubhankar
    • Advances in materials Research
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    • v.9 no.2
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    • pp.115-131
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    • 2020
  • Limit elastic speed analysis of Al/SiC-based functionally graded annular disk of uniform thickness has been carried out for two cases, namely: metal-rich and ceramic rich. In the present study, the unknown field variable for radial displacement is solved using variational method wherein the solution was obtained by Galerkin's error minimization principle. One of the objectives was to identify the variation of induced stress in a functionally graded disk of uniform thickness at limit elastic speed using modified rule of mixture by comparing the induced von-Mises stress with the yield stress along the disk radius, thereby locating the yield initiation. Furthermore, limit elastic speed has been reported for a combination of varying grading index (n) and aspect ratios (a/b).Results indicate, limit elastic speed increases with an increase in grading indices. In case of an increase in aspect ratio, limit elastic speed increases up to a critical value beyond which it recedes. Also, the objective was to look at the variation of yield stress corresponding to volume fraction variation within the disk which later helps in material tailoring. The study reveals the qualitative variation of yield stress for FG disk with volume fraction, resulting in the possibility of material tailoring from the processing standpoint, in practice.

The Effect of Polarizability on Rate and Reaction Mechanism: Reactions of S-Aryl Substituted Thiobenzoates with $HO-$ and Aryloxide Ions

  • Ik-Hwan Um;Sang-Eun Chun;Dong-Sook Kwon
    • Bulletin of the Korean Chemical Society
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    • v.12 no.5
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    • pp.510-514
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    • 1991
  • Second-order rate constants have been determined spectrophotometrically for reactions of S-p-nitrophenyl substituted thiobenzoates with various phenoxide ions and S-aryl substituted thiobenzoates with $HO^-$ ion. Thiol esters have been found to be more reactive than the corresponding oxygen esters toward phenoxide ions. The high reactivity of thiol esters relative to oxygen esters becomes insignificant as the basicity of the nucleophile increases. Furthermore, the highly basic $HO^-$ ion is less reactive toward thiol esters than oxygen esters. The significant dependence of the reactivity of thiol esters on the basicity of nucleophiles has been attributed to the nature of the HSAB principle. The present kinetic study has also revealed that the reactivity of thiol esters compared to oxygen esters is not so pronounced as expected based on the enhanced nucleofugicity of thiol esters. However, the effects of substituents in the nucleophile and in the acyl moiety of the substrate on rate appear to be significant. These kinetic results have led to a conclusion that the present reactions proceed via a rate-determining formation of a tetrahedral intermediate followed by a fast breakdown of it. The magnitude of the ${\beta}$ values shows no tendency either to increase or to decrease with the intrinsic reactivity of the reagents. The constancy of ${\beta}$ values in the present system is suggestive that the RSP should have limited applicability.

A Simplified Torque Ripple Reduction using the Current Shaping of the Flux Switched Reluctance Motor

  • Lee, Heon-Hyeong;Wang, Qi;Kim, Se-Joo;Choi, Woong-Chul;Lee, Geun-Ho
    • Journal of Magnetics
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    • v.17 no.3
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    • pp.200-205
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    • 2012
  • Recently, applications of the reluctance torque motor have been quite limited due to their inherent limitation of noise and vibration and thus, researches on the reluctance motor have been limited as well. However, with the tremendous increase in the cost of rare earth material magnets, studies of the reluctance torque motor are being conducted more and more. In principle, reluctance torque is generated when the inductance is changed. Therefore, in order to generate continuous torque in the switched reluctance motor, it is necessary to figure out the exact inductance level corresponding to the rotor position and the current level to be applied in that rotor position, respectively. If the current level or the rotor position is not accurately determined, then the generated reluctance torque becomes unstable and undesirable torque ripples prevail to eventually cause noise and vibrations. In this research, a flux switched reluctance motor (FSRM), which is classified into the switched reluctance motor (SRM), was studied. A methodology using the current shaping control according to the rotor position was proposed. Based on the proposed methodology, the optimal current waveform and the torque distribution function for the FSRM to minimize torque ripple was established and demonstrated in this paper.

The Choice of Applicable Law and the Limitations of Party Autonomy - Focusing on International Sports Arbitration - (중재의 준거법 선택과 당사자 자치의 제한 - 국제스포츠중재를 중심으로 -)

  • Yoo, So-Mi
    • Journal of Arbitration Studies
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    • v.31 no.2
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    • pp.23-46
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    • 2021
  • Sports disputes have specific characteristics compared to disputes that arise in the field of commerce. One particularity is the judicial system in which the CAS plays a key role as the International Supreme Court for sports-related matters. The CAS Code applies whenever the parties agree to submit a sports-related dispute to the CAS(Art. R27). Once the parties to the arbitration agreement have decided that the CAS Code should govern their proceedings. The parties' autonomy is, however, limited to the provisions of the CAS Code that provide for such a corresponding autonomy. The application of the mandatory rules contained in the CAS Code cannot be excluded. In CAS appeals arbitration proceedings, the Panel shall decide the dispute according to the applicable sports regulations and, subsidiarily, to the rules of law chosen by the parties(Art. R58). In international sports disputes, the uniform application and interpretation of the relevant regulations are essential. Therefore, Art. R58 should be applied as a mandatory rule without any changes. Regulations of the sports organizations are to be qualified as valid rules of law. CAS panels may also apply the so-called lex sportiva to the merits before considering statutory provisions of national jurisdictions. In this way, the specificities in (international) sports disputes can be taken into account without the need to further examine the application of national legal standards.

Nonlinear thermal buckling of bi-directional functionally graded nanobeams

  • Gao, Yang;Xiao, Wan-shen;Zhu, Haiping
    • Structural Engineering and Mechanics
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    • v.71 no.6
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    • pp.669-682
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    • 2019
  • We in this article study nonlinear thermal buckling of bi-directional functionally graded beams in the theoretical frameworks of nonlocal strain graded theory. To begin with, it is assumed that the effective material properties of beams vary continuously in both the thickness and width directions. Then, we utilize a higher-order shear deformation theory that includes a physical neutral surface to derive the size-dependent governing equations combining with the Hamilton's principle and the von $K{\acute{a}}rm{\acute{a}}n$ geometric nonlinearity. It should be pointed out that the established model, containing a nonlocal parameter and a strain gradient length scale parameter, can availably account for both the influence of nonlocal elastic stress field and the influence of strain gradient stress field. Subsequently, via using a easier group of initial asymptotic solutions, the corresponding analytical solution of thermal buckling of beams is obtained with the help of perturbation method. Finally, a parametric study is carried out in detail after validating the present analysis, especially for the effects of a nonlocal parameter, a strain gradient length scale parameter and the ratio of the two on the critical thermal buckling temperature of beams.

Free vibration and buckling analyses of functionally graded annular thin sector plate in-plane loads using GDQM

  • Mohammadimehr, Mehdi;Afshari, Hasan;Salemi, M.;Torabi, K.;Mehrabi, Mojtaba
    • Structural Engineering and Mechanics
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    • v.71 no.5
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    • pp.525-544
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    • 2019
  • In the present study, buckling and free vibration analyses of annular thin sector plate made of functionally graded materials (FGMs) resting on visco-elastic Pasternak foundation, subjected to external radial, circumferential and shear in-plane loads is investigated. Material properties are assumed to vary along the thickness according to an power law with Poisson's ratio held constant. First, based on the classical plate theory (CPT), the governing equation of motion is derived using Hamilton's principle and then is solved using the generalized differential quadrature method (GDQM). Numerical results are compared to those available in the literature to validate the convergence and accuracy of the present approach. Finally, the effects of power-law exponent, ratio of radii, thickness of the plate, sector angle, and coefficients of foundation on the fundamental and higher natural frequencies of transverse vibration and critical buckling loads are considered for various boundary conditions. Also, vibration and buckling mode shapes of functionally graded (FG) sector plate have been shown in this research. One of the important obtained results from this work show that ratio of the frequency of FG annular sector plate to the corresponding values of homogeneous plate are independent from boundary conditions and frequency number.

Scientific Reasoning Types and Levels in Science Writings of Elementary School Students (초등학생들의 과학 글쓰기에 나타난 과학적 추론의 유형과 수준)

  • Lim, Ok-Ki;Kim, Hyo-Nam
    • Journal of Korean Elementary Science Education
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    • v.37 no.4
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    • pp.372-390
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    • 2018
  • The purpose of this research is to know the scientific reasoning ability of elementary students. In order to find it, 320 elementary students wrote a report about germination of the 700 or 2,000 years old seeds. Their writings were analyzed by scientific writing analysis frameworks, Scientific Reasoning Types and Scientific Reasoning Level Criteria developed by Lim (2018). Minto Pyramid Principles was used to show statements and relations of statements related to scientific reasoning. This paper showed scientific reasoning statements of elementary students about germination of seeds. The characteristics of scientific reasoning of elementary students were as follows. In the process of logical writing by the types of scientific reasoning, many students showed various characteristics and different levels. In the writings based on inductive reasoning, they did not distinguish between common features and differences of cases, and did not derive the rules based on common features and differences of the cases. In the writings based on deductive reasoning, there were cases where the major premise corresponding to the principle or rule was omitted and only the phenomenon was described, or the rule was presented but not connected with the case. In the writings based on abductive reasoning, the ability to selectively use the background knowledge related to the question situation was not sufficient, and borrowing of similar background knowledge, which was commonly used in other situations, was very rare.