• 제목/요약/키워드: Physical parameters

검색결과 2,810건 처리시간 0.034초

Rain-wind induced vibration of inclined stay cables -Part I: Experimental investigation and physical explanation

  • Cosentino, Nicola;Flamand, Olivier;Ceccoli, Claudio
    • Wind and Structures
    • /
    • 제6권6호
    • /
    • pp.471-484
    • /
    • 2003
  • The rain-wind induced vibration of stays is a phenomenon discovered recently and not well explained yet. As it is influenced by a wide range of physical parameters (cable size and shape, wind speed, direction and turbulence, rain intensity, material repellency and roughness, cable weight, damping and pre-strain), this peculiar phenomenon is difficult to reproduce in laboratory controlled conditions. A successful wind tunnel experimental campaign, in which some basic physical quantities were measured, allowed an extensive analysis as to identify the parameters of the rain-wind induced excitation. The unsteady pressure field and water thickness around a cable model were measured under rainy-excited conditions. The knowledge of those parameters provided helpful information about the air-flow around the cable and allowed to clarify the physical phenomenon which produces the excitation.

도시 환경음의 쾌적성 평가를 통한 새로운 지수 적용가능성 분석 (Feasibility of Alternative Physical Parameters by Subjective Evaluation for Urban Environmental Sounds)

  • 박현구;장길수
    • KIEAE Journal
    • /
    • 제8권1호
    • /
    • pp.31-36
    • /
    • 2008
  • For the comfortable housing life, comfortable and pleasant urban environment should be created for the people living in house and in city. There are lots of environmental conditions in city affecting house and life. Also most of all the noise pollution have been become major factor that makes people's life uncomfortable. Recently soundscape researches have been performed to create comfortable urban environment and various studies on the evaluation of urban environmental sounds are now undergoing. This study aimed to analyse the subjective characteristics through the subjective evaluation to the sounds measured with physical parameters and eventually to find out alternative evaluation method for urban environmental sounds. Adjectives applied to previous studies were used for the subjective evaluation and sound sources recorded in specific places were presented with picture at the same time. As a result, new physical parameters such as Lmax, Unbiased Annoyance, G, N and EmT have a feasibility to evaluation of urban environment sounds in terms of acoustic comfort.

대동작 기능 평가도구, 대동작 수행능력 측정도구, 그리고 시공간적 보행변수와의 상관관계 (Correlations Among GMFM, GMPM, and the Spatiotemporal Gait Parameters)

  • 박소연;고명숙;이충휘
    • 한국전문물리치료학회지
    • /
    • 제11권2호
    • /
    • pp.63-70
    • /
    • 2004
  • These were two main purposes of this study. The first was to research the relevance between gross motor function measurement (GMFM) and the spatiotemporal parameters of gait in children with cerebral palsy. The second was to research the relevance between gross motor performance measure (GMPM) and the spatiotemporal gait parameters. Twelve children ($6.0{\pm}1.8$ years) with cerebral palsy participated in this study. GMFM and GMPM were performed and the spatiotemporal parameters of gait were measured by using WalkWay MG-1000. There were no significant correlations between the GMFM score and the stride length, step length, step width, cadence, and velocity (p>.05). The GMPM score also had no significant correlation with the spatiotemporal gait parameter (p>.05).

  • PDF

Ultrasonic velocity as a tool for mechanical and physical parameters prediction within carbonate rocks

  • Abdelhedi, Mohamed;Aloui, Monia;Mnif, Thameur;Abbes, Chedly
    • Geomechanics and Engineering
    • /
    • 제13권3호
    • /
    • pp.371-384
    • /
    • 2017
  • Physical and mechanical properties of rocks are of interest in many fields, including materials science, petrophysics, geophysics and geotechnical engineering. Uniaxial compressive strength UCS is one of the key mechanical properties, while density and porosity are important physical parameters for the characterization of rocks. The economic interest of carbonate rocks is very important in chemical or biological procedures and in the field of construction. Carbonate rocks exploitation depends on their quality and their physical, chemical and geotechnical characteristics. A fast, economic and reliable technique would be an evolutionary advance in the exploration of carbonate rocks. This paper discusses the ability of ultrasonic wave velocity to evaluate some mechanical and physical parameters within carbonate rocks (collected from different regions within Tunisia). The ultrasonic technique was used to establish empirical correlations allowing the estimation of UCS values, the density and the porosity of carbonate rocks. The results illustrated the behavior of ultrasonic pulse velocity as a function of the applied stress. The main output of the work is the confirmation that ultrasonic velocity can be effectively used as a simple and economical non-destructive method for a preliminary prediction of mechanical behavior and physical properties of rocks.

On-load Parameter Identification of an Induction Motor Using Univariate Dynamic Encoding Algorithm for Searches

  • Kim, Jong-Wook;Kim, Nam-Gun;Choi, Seong-Chul;Kim, Sang-Woo
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 제어로봇시스템학회 2004년도 ICCAS
    • /
    • pp.852-856
    • /
    • 2004
  • An induction motor is one of the most popular electrical apparatuses owing to its simple structure and robust construction. Parameter identification of the induction motor has long been researched either for a vector control technique or fault detection. Since vector control is a well-established technique for induction motor control, this paper concentrates on successive identification of physical parameters with on-load data for the purpose of condition monitoring and/or fault detection. For extracting six physical parameters from the on-load data in the framework of the induction motor state equation, unmeasured initial state values and profiles of load torque have to be estimated as well. However, the analytic optimization methods in general fail to estimate these auxiliary but significant parameters owing to the difficulty of obtaining their gradient information. In this paper, the univariate dynamic encoding algorithm for searches (uDEAS) newly developed is applied to the identification of whole unknown parameters in the mathematical equations of an induction motor with normal operating data. Profiles of identified parameters appear to be reasonable and therefore the proposed approach is available for fault diagnosis of induction motors by monitoring physical parameters.

  • PDF

노력성 호흡운동을 통한 편마비환자의 기능적 보행지수 개선 (The improve of hemiplegic patients functional ambulation profile by forceful respiratory exercise)

  • 김병조;배성수;황보각
    • The Journal of Korean Physical Therapy
    • /
    • 제16권1호
    • /
    • pp.32-48
    • /
    • 2004
  • The purpose of this study was to evaluate the change of functional ambulation profile(FAP) and temporal-spatial gait parameters in hemiplegic patient by forceful respiratory exercise. 28 Hemiplegic patients due to stroke was randomized in 3 groups, forceful expiratory training(FET), forceful inspiratory training(FIT) and control group. In the experimental groups, ordinary physical therapy with forceful expiratory training and forceful inspiratory training for 20 minutes duration 3 times per week for 6 weeks were respectively performed. In the control group, only ordinary physical therapy was done. FAP and temporal-spatial gait parameters was measured at before and after experiments. The results of this experimental study were as follows : 1. In comparison of FAP before and after experiment, the FAP was significantly increased in the FET and FIT group (p<.01). In comparison of difference of FAP among 3 groups, there was the significant difference between the FIT group and the control group (p<.05). 2. The results of temporal-spatial gait parameters are as follows : 1) In comparison of gait velocity before and after experiment, the gait velocity was significantly increased in the FET and FIT group (p<.05). In comparison of difference of the gait velocity among 3 groups, there was the significantly difference between the FIT group and the control group (p<.05). 2) In comparison of gait cadence before and after experiment, the gait cadence was significantly increased in FIT group (p<.05). In comparison of the difference of the gait cadence among 3 groups, there was no significant difference between the FIT group and the control group (p>.05). Based on these results, it is concluded that the forced respiratory exercise program for 6 weeks can be improve the FAP and temporal-spatial gait parameters in hemiplegic patients. Therefore, the forced respiratory exercise is useful to improve the walking ability in hemiplegic patients.

  • PDF

Effect of Post-Activation Potentiation according to Sequence of Velocity Using Isokinetic Device on Short-Term Performance of Lower Extremity: Taekwondo Athletes and Healthy Adults

  • Sang-Woo Pyun;Seong-Eun Kim;Jong-Wan Kim;Dongyeop Lee;Ji-Heon Hong;Jae-Ho Yu;Jin-Seop Kim;Hyun Suk Yang;Seong-gil Kim
    • The Journal of Korean Physical Therapy
    • /
    • 제34권6호
    • /
    • pp.298-303
    • /
    • 2022
  • Purpose: The purpose of this study was to figure out how PAP (Post-Activation Potentiation) phenomenon affects short-term performance efficiently. Methods: This study was conducted with 18 Taekwondo athletes and 16 healthy adults. By using isokinetic dynamometer, two different intervention, TDP (Top-down program) and BUP (Bottom-up program), were performed to measure isokinetic parameter; (peak torque: PT, total work: TW, average power: AP, and average torque: AT) of knee extensor for intragroup, intergroup comparison and two-way ANOVA. Results: The Taekwondo athletes group showed statistically significant differences in all isokinetic parameters PT, TW, AP, and AT after TDP (p<0.05). However, in the healthy adult group, the difference in isokinetic parameters according to the exercise sequence was not statistically significant. (p>0.05). PT and TW at TDP were statistically significant (p<0.05) when the rate of change in TDP and BUP was compared and analyzed considering the difference in physical ability between the Taekwondo athlete group and the healthy adult group. However, AP and AT were not statistically significant. Finally, when examining the interaction between the two groups and two exercise sequence according to isokinetic parameters, only TW (p<0.05) showed a statistically significant interaction, while PT (P=0.099), AP (P=0.103), and AT (P=0.096) did not. This study suggests that short-term performance can be improved through the PAP phenomenon when TDP is applied to the Taekwondo group. Conclusion: According to our result, for Taekwondo athletes, if the goal is to improve short-term performance just before the main game, we suggest a training program through TDP.

경직성 양하지마비아의 발목 보조기 착용에 따른 체 중심및 보행속도에 의한 보행인자 변화연구 (A Study on Change in Gait Parameters Related to the Cop and Velocity Resulting from the Use of Ankle Foot Orthosis in Spastic Diplegia)

  • 박미숙;김용성;황태연;김용남
    • 대한임상전기생리학회지
    • /
    • 제10권1호
    • /
    • pp.23-28
    • /
    • 2012
  • Purpose : The objectives of this study were to examine changes in gait parameters related to the COP and gait velocity resulting from the use of ankle foot orthosis, and to provide information for the prescription of ankle foot orthosis and gait rehabilitation training. Methods : We sampled a control group of 14 normal children of the same age as the spastic diplegia (spastic diplegia used ankle foot orthosis) and measured their COP at barefoot gait and their gait parameters at three gait velocities. Change in the COP according to the use of ankle foot orthosis measured one-way ANOVA and Gait parameters according to gait velocity used repeated measures ANOVA. Results : As a result of analyzing change in the COP it became close to that of normal children, and changes in gait parameters such as step width, stride length and stride time also became close to those of normal children. Conclusion : In conclusion, when spastic diplegia used ankle foot orthosis, their balancing ability was improved as a result of decreased change in the COP, and their changes in gait parameters also became close to those of the control group. These results show that the use of ankle foot orthosis improves spastic diplegia gait functions.

육체운동이 사염화탄소의 간독성에 미치는 영향

  • 김민경;김영철
    • Toxicological Research
    • /
    • 제7권2호
    • /
    • pp.165-171
    • /
    • 1991
  • Effects of forced physical exercise on the CCl4 hepatotoxicity were examined in adult female rats. Rats were treated with CCl4 (2 mmol/kg, ip) and introduced into a cylindrical cage rotating at 9 rpm for 20 min/hr for 6 hr. Eighteen hr following the termination of exercise serum sorbitol dehydrogenase (SDH), glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT) activities and glucose-6-phosphatase activity were determined as parameters for hepatotoxicity. Physical exercise inhibited the $CCI_{4-}$induced increases in SDH, GOT, GPT activity, and glucose-6-phosphatase activity were determined as parameters for hepatotoxicity.

  • PDF

Cell thickness dependence of liquid crystal parameters

  • Sood, Nitin;Khosla, Samriti;Singh, Darshan;Bawa, S.S.
    • Journal of Information Display
    • /
    • 제13권1호
    • /
    • pp.31-36
    • /
    • 2012
  • Ferroelectric liquid crystal parameters, spontaneous polarization, and transition temperature were studied as a function of cell thickness. These parameters were found to increase with increasing cell thickness, but an exception was observed for the transition temperature in the case of a thin cell. A simple Landau model is presented to interpret the theoretical and experimental observations. The anomalous behavior is attributed to the electroclinic effect and is explained using the Landau model.