Assessments of muscle fibre distribution by non-invasive methods

성은숙,소재무,강성선 국민체육진흥공단 한국스포츠정책과학원 2020 International Journal of Applied Sports Sciences Vol.32 No.2

The objective of the present study was to assess muscle fibre composition by non-invasive methods for various sports events. 53 males of marathon (n=5), football (n=22), baseball (n=14), basketball (n=8) and tennis (n=4) athletes volunteered to participate in this study. The following 7 tests (overhead medicine ball throw, pull up, standing broad jump, sit up, shuttle run 10 x5, push up, vertical jump) are relatively easy to perform and to gather information about fibre composition through fitness levels. It can be used to assess the performance of strength using standard tables and to receive an indication of the degree of their share of fast (type II) and slow (type I) muscle fibres. For the study, a data analysis program in Microsoft Excel was used to view the mean and standard deviation of muscle fibre types. As a result, it was possible to speculate that the ratio of muscle fibre types differed according to the type of exercise. The results were obtained after sport motor tests of the mean value of muscle fibre composition by different sports events. Fibre type distribution remained with about 74.8% type 1 and 25.2% type 2 by marathoners, 43.8% type 1 and 53.2% type 2 by football athletes, 36.3% type 1 and 63.8% type 2 by baseball athletes, 46.6% type 1 and 53.5% type 2 by basketball athletes, and 40.0% type 1 and 60.0% type 2 by tennis athletes. Through these tests, the direction of the athletes’ muscle development can be considered, and it is possible to check the muscle fibre composition of elite athletes for the improvement of performance for each sport event. Moreover, it assumes that if this test is used for children, adolescents and young athletes, it will help to design scientific and effective training programs, thereby improving athletes’ ability to perform.

Ultrahigh-speed distributed Brillouin reflectometry

Mizuno, Yosuke,Hayashi, Neisei,Fukuda, Hideyuki,Song, Kwang Yong,Nakamura, Kentaro Nature Publishing Group 2016 Light, science & applications Vol.5 No.12

<P>Optical fibre sensors based on Brillouin scattering have been vigorously studied in the context of structural health monitoring on account of their capacity for distributed strain and temperature measurements. However, real-time distributed strain measurement has been achieved only for two-end-access systems; such systems reduce the degree of freedom in embedding the sensors into structures, and furthermore render the measurement no longer feasible when extremely high loss or breakage occurs at a point along the sensing fibre. Here, we demonstrate real-time distributed measurement with an intrinsically one-end-access reflectometry configuration by using a correlation-domain technique. In this method, the Brillouin gain spectrum is obtained at high speed using a voltage-controlled oscillator, and the Brillouin frequency shift is converted into a phase delay of a synchronous sinusoidal waveform; the phase delay is subsequently converted into a voltage, which can be directly measured. When a single-point measurement is performed at an arbitrary position, a strain sampling rate of up to 100 kHz is experimentally verified by detecting locally applied dynamic strain at 1 kHz. When distributed measurements are performed at 100 points with 10 times averaging, a repetition rate of 100 Hz is verified by tracking a mechanical wave propagating along the fibre. Some drawbacks of this ultrahigh-speed configuration, including the reduced measurement accuracy, lowered spatial resolution and limited strain dynamic range, are also discussed.</P>

Two Statistical Scrutinize of Impact Strength and Strength Reliability of Steel Fibre-Reinforced Concrete

G. Murali,R. Gayathri,V. R. Ramkumar,K. Karthikeyan 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.1

The variations in impact strength of steel Fibre Reinforced Concrete (FRC) were statistically, commanded in this research. For this purpose, the experimental impact test results of earlier researchers were investigated using two statistical approaches. Firstly, normality test was carried out on first crack strength (N1) and failure strength (N2) using distribution plot and its accuracy was verified with Kolmogorov-Smirnov, Shapiro-Wilk and Chen-Shapiro test. Secondly, strength reliability analysis was carried out using two parameter Weibull distribution and their Weibull parameters were determined using three methods viz., Empherical Method of Justus (EMJ), Method of Moments (MOM) and Empherical Method of Lysen (EML). Results suggested that, if three samples are used to determine the N1 value for researchers’ data, at 95% levels of confidence, then the error in the measured value is about 50%. The 0.1 reliability level of the impact strength values of EMJ, EML and MOM were 153, 120 and 153 respectively in case of N1 and were 198, 156, and 198 respectively in case of N2 based on earlier researcher’s data.

Statistical variations in the impact resistance and mechanical properties of polypropylene fiber reinforced self-compacting concrete

M. Mastali,A. Dalvand,M. Fakharifar 사단법인 한국계산역학회 2016 Computers and Concrete, An International Journal Vol.18 No.1

Extensive experimental studies on remarkable mechanical properties Polypropylene Fibre Reinforced Self-compacting Concrete (PFRSCC) have been executed, including different fibre volume fractions of Polypropylene fibers (0.25%, 0.5%, 0.75%, and 1%) and different water to cement ratios (0.21, 0.34, 0.38, and 0.41). The experimental program was carried out by using two hundred and sixteen specimens to obtain the impact resistance and mechanical properties of PFRSCC materials, considering compressive strength, splitting tensile strength, and flexural strength. Statistical and analytical studies have been mainly focused on experimental data to correlate of mechanical properties of PFRSCC materials. Statistical results revealed that compressive, splitting tensile, and flexural strengths as well as impact resistance follow the normal distribution. Moreover, to correlate mechanical properties based on acquired test results, linear and nonlinear equations were developed among mechanical properties and impact resistance of PFRSCC materials.

FIBRED RIEMANNIAN SPACE WITH KENMOTSU STRUCTURE

Kim, Byung-Hak 한국전산응용수학회 1999 Journal of applied mathematics & informatics Vol.6 No.3

K. Kenmotsu introduced and studied the so-called Kenmotsu manifold related to the warped product space. In this paper we charac-terize a Kenmotsu Manifold using the fibred Riemannian space.

Health Monitoring for Large Structures using Brillouin Distributed Sensing

Thevenaz, L.,Chang, KT.,Nikles, M. The Korean Society for Nondestructive Testing 2005 한국비파괴검사학회지 Vol.25 No.6

Brillouin time-domain analysis in optical fibres is a novel technique making possible a distributed measurement of temperature and strain over long distance and will deeply modify our view about monitoring large structures, such as dams, bridges, tunnels and pipelines, Optical fibre sensing will certainly be a decisive tool for securing dangerous installations and detecting environmental and industrial threats.

Comparative Thermal Analysis of Carbon Nanotubes and Their Metal Composites with Copper and Aluminum as Winding Material in Induction Motor

Hassan Atazaz,Quanfang Chen,Abbas Sajid,Jie Liu,Youming Luo,Hussain Fida 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.4

The ability to predict the thermal transport properties of electrical, electronic, and mechanical components becomes increasingly important as characteristic material sizes shrink to the micron and nanometre scale. The maximum hot-spot temperature is one of the thermal and electrical effi ciency design constraints. In this paper, the thermal analysis of a three-phase induction machine is investigated by means of replacing the winding materials. The temperature distribution is evaluated from a two-dimensional fi nite element approach, using COMSOL Multiphysics software. The temperature rise has been analyzed when conventional winding materials are substituted by novel nanomaterials, namely, carbon nanotube, carbon nanotube aluminum, and carbon nanotube copper composite wires. Overall, the proposed model with carbon nanotube copper composite wire winding machine shows better thermal performance among the studied carbon-based winding materials. Thus, we conclude that the carbon nano-based materials for thermal management in electrical machine winding provide a viable and eff ective alternative to existing materials.

Particle deposition in random fibrous porous materials

Richardson Teixeira,Antonio F. Miguel 대한기계학회 2007 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.21 No.11

Porous filters are widely used to control air pollution and have different industrial applications since they constitute a reliable and low cost solution to separate particulate matter from an air stream. In this study, the particle deposition within 3D porous filters subjected to low-frequency acoustic fields is studied following a numerical approach. Findings demonstrate that the application of acoustic waves enhances the deposition of particles, which in turn improves filter performance. It is shown that frequencies ranging from 200 to 1000 Hz (intensity 120 dB) increase particle deposition up to 2.5 times. Besides, the manner in which fibres are distributed in the porous material and the filter porosity affect considerably the number of particles deposited, for filters subjected to the same filtration velocity.