• 제목/요약/키워드: Stretching technique

검색결과 161건 처리시간 0.029초

Heat and mass transfer of a second grade magnetohydrodynamic fluid over a convectively heated stretching sheet

  • Das, Kalidas;Sharma, Ram Prakash;Sarkar, Amit
    • Journal of Computational Design and Engineering
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    • 제3권4호
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    • pp.330-336
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    • 2016
  • The present work is concerned with heat and mass transfer of an electrically conducting second grade MHD fluid past a semi-infinite stretching sheet with convective surface heat flux. The analysis accounts for thermophoresis and thermal radiation. A similarity transformations is used to reduce the governing equations into a dimensionless form. The local similarity equations are derived and solved using Nachtsheim-Swigert shooting iteration technique together with Runge-Kutta sixth order integration scheme. Results for various flow characteristics are presented through graphs and tables delineating the effect of various parameters characterizing the flow. Our analysis explores that the rate of heat transfer enhances with increasing the values of the surface convection parameter. Also the fluid velocity and temperature in the boundary layer region rise significantly for increasing the values of thermal radiation parameter.

RADIATION EFFECTS ON MHD BOUNDARY LAYER FLOW OF LIQUID METAL OVER A POROUS STRETCHING SURFACE IN POROUS MEDIUM WITH HEAT GENERATION

  • Venkateswarlu, M.;Reddy, G. Venkata Ramana;Lakshmi, D. Venkata
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제19권1호
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    • pp.83-102
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    • 2015
  • The present paper analyses the radiation effects of mass transfer on steady nonlinear MHD boundary layer flow of a viscous incompressible fluid over a nonlinear porous stretching surface in a porous medium in presence of heat generation. The liquid metal is assumed to be gray, emitting, and absorbing but non-scattering medium. Governing nonlinear partial differential equations are transformed to nonlinear ordinary differential equations by utilizing suitable similarity transformation. The resulting nonlinear ordinary differential equations are solved numerically using Runge-Kutta fourth order method along with shooting technique. Comparison with previously published work is obtained and good agreement is found. The effects of various governing parameters on the liquid metal fluid dimensionless velocity, dimensionless temperature, dimensionless concentration, skin-friction coefficient, Nusselt number and Sherwood number are discussed with the aid of graphs.

다구치 직교배열을 이용한 평면변형률 장출실험용 금형의 최적설계 (Optimization of the tool geometry of PSST using taguchi's orthogonal matrix)

  • 김영석
    • 대한기계학회논문집A
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    • 제21권12호
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    • pp.2073-2080
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    • 1997
  • Recently, the plane strain puch stretching test(called PSST) has been developed and used successfully in the evaluation of the press formability of automotive steel sheets. In this paper, the optimum punch geometry of the original PSST tool was investigated by the FEM analysis. The puch length, crown and corner radius are chosen to be optimized according to the Taguchi's experiment technique with the $L_4$ orthogonal array.

A new size-dependent shear deformation theory for wave propagation analysis of triclinic nanobeams

  • Karami, Behrouz;Janghorban, Maziar
    • Steel and Composite Structures
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    • 제32권2호
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    • pp.213-223
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    • 2019
  • For the first time, longitudinal and transverse wave propagation of triclinic nanobeam is investigated via a size-dependent shear deformation theory including stretching effect. Furthermore, the influence of initial stress is studied. To consider the size-dependent effects, the nonlocal strain gradient theory is used in which two small scale parameters predict the behavior of wave propagation more accurately. The Hamiltonian principle is adopted to obtain the governing equations of wave motion, then an analytic technique is applied to solve the problem. It is demonstrated that the wave characteristics of the nanobeam rely on the wave number, nonlocal parameter, strain gradient parameter, initial stress, and elastic foundation. From this paper, it is concluded that the results of wave dispersion in isotropic and anisotropic nanobeams are almost the same in the presented case study. So, in this case, triclinic nanobeam can be approximated with isotropic model.

Robust quasi 3D computational model for mechanical response of FG thick sandwich plate

  • Achouri, Fatima;Benyoucef, Samir;Bourada, Fouad;Bouiadjra, Rabbab Bachir;Tounsi, Abdelouahed
    • Structural Engineering and Mechanics
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    • 제70권5호
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    • pp.571-589
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    • 2019
  • This paper aims to develop a quasi-3D shear deformation theory for the study of bending, buckling and free vibration responses of functionally graded (FG) sandwich thick plates. For that, in the present theory, both the components of normal deformation and shear strain are included. The displacement field of the proposed model contains undetermined integral terms and involves only four unknown functions with including stretching effect. Using Navier's technique the solution of the problem is derived for simply supported sandwich plate. Numerical results have been reported, and compared with those available in the open literature were excellent agreement was observed. Finally, a detailed parametric study is presented to demonstrate the effect of the different parameters on the flexural responses, free vibration and buckling of a simply supported sandwich plates.

Multiplexed single-molecule flow-stretching bead assay for DNA enzymology

  • Lee, Ryanggeun;Yang, Keunsang;Lee, Jong-Bong
    • BMB Reports
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    • 제52권10호
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    • pp.589-594
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    • 2019
  • Single-molecule techniques have been used successfully to visualize real-time enzymatic activities, revealing transient complex properties and heterogeneity of various biological events. Especially, conventional force spectroscopy including optical tweezers and magnetic tweezers has been widely used to monitor change in DNA length by enzymes with high spatiotemporal resolutions of ~nanometers and ~milliseconds. However, DNA metabolism results from coordination of a number of components during the processes, requiring efficient monitoring of a complex of proteins catalyzing DNA substrates. In this min-review, we will introduce a simple and multiplexed single-molecule assay to detect DNA substrates catalyzed by enzymes with high-throughput data collection. We conclude with a perspective of possible directions that enhance capability of the assay to reveal complex biological events with higher resolution.

Flow of casson nanofluid along permeable exponentially stretching cylinder: Variation of mass concentration profile

  • Iqbal, Waheed;Jalil, Mudassar;Khadimallah, Mohamed A.;Hussain, Muzamal;Naeem, Muhammad N.;Naim, Abdullah F. Al;Mahmoud, S.R.;Tounsi, Abdelouahed
    • Steel and Composite Structures
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    • 제38권1호
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    • pp.33-45
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    • 2021
  • The Runge-Kutta method of 6th-order has been employed in this paper to analyze the flow of Casson nanofluid along permeable exponentially stretching cylinder. The modeled PDEs are changed into nonlinear ODEs through appropriate nonlinear transformations. The aim of the paper is to investigate the effects of different parameters such as Casson fluid parameter, slip parameter, suction parameter, Prandtl number, Lewis number, Brownian motion parameter, and thermophoresis parameter, with the variation of mass concentration profile. Numerical results are attained using a renowned numerical scheme shooting technique and for the authenticity of present methodlogy, the results are verified with earlier open text.

Computation of boundary layer flow of porous medium based on finite difference method

  • Mohamed Amine Khadimallah;Mudassar Jalil;Muzamal Hussain;Elimam Ali
    • Advances in concrete construction
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    • 제17권1호
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    • pp.37-43
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    • 2024
  • In this paper, boundary layer flow is observed through stretching cylinder exponentially with non-linear velocity. This cylinder is rested in porous medium. Appropriate similarity transformation is employed for the conversion of governing PDEs into ODEs. To compute the problem and solution series numerical method is applied and evaluated by using finite difference Keller-Box method. The velocity ratio, permeability parameter, Reynold number is figure out to examine the effect of on velocity profile. Fluid velocity and skin friction coefficient goes down with increment of Reynold number and permeability parameter. While reverse behavior is reported for velocity ratio. The results are validated with earlier investigations and found very well.

근에너지기법 적용이 30~40대 만성 허리통증 환자의 통증과 압통에 미치는 영향 (Effect of application of muscle energy technique on patients with chronic back pain aged 30~40 years)

  • 박재철;유진호
    • 대한물리치료과학회지
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    • 제28권3호
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    • pp.66-75
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    • 2021
  • Background: The purpose of this study is to investigate the effect of muscle energy technique and stretching on pain and pressure pain fear-avoidance beliefs questionnaire in patients with chronic back pain aged 30~40 years. Design: Pretest-Posttest design: single blind. Methods: The subjects of this study were 30, 22 males and 8 females between the ages of 30 and 40 with chronic back pain. Each group consists of three groups of 10 people. Changes in back pain were observed using Korean version of Oswestry Disability Index (K-ODI), visual analogue scale (VAS), and fear-avoidance beliefs questionnaire (FABQ). And the change in tenderness was observed using digital pressure statistics. Changes between groups after 3 weeks were compared with those before the experiment using one way ANOVA to determine the changes after 3 weeks. And the change within the group was investigated using the paired t-test. Results: As a result of the experiment, there were significant differences in the group changes in K-ODI, VAS, FABQ, and pressure pain (p<0.05). And there was a significant difference in all items after 3 weeks compared to before the experiment (p<0.05). Conclusion: In patients with chronic back pain, the muscle energy technique and stretching gave a significant difference in pain and pressure pain, fear-avoidance beliefs questionnaire changes. And this result suggests the possibility of providing basic data for future research and clinical physiotherapy intervention.

고유수용성신경근촉진법 손목테이핑 처치 전 율동적 안정 기법이 손목통증환자의 통증과 악력에 미치는 영향 (Effect of Rhythmic Stabilization Technique, before Proprioceptive Neuromuscular Facilitation Wrist Taping, on Grip Strength and Pain in Wrist Pain Patients)

  • 김창헌;김범룡;강미경
    • PNF and Movement
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    • 제14권2호
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    • pp.105-112
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    • 2016
  • Purpose: The purpose of this study was to examine the effects of proprioceptive neuromuscular facilitation (PNF) wrist taping, after the application of a rhythmic stabilization (RS) technique, on the decrease of pain and the increase of grip strength in physical therapists who complained of wrist pain and to provide basic data on interventions for wrist pain patients. Methods: The subjects were 15 peoples in their 20s who complained of pain with a visual analogue scale (VAS) at five points or higher due to overuse of their wrists. They were randomly assigned to a control group, to which PNF wrist taping was applied after stretching (n=7), or to an experimental group (n=8), to which PNF wrist taping was applied after application of the RS technique of PNF. The experiment was conducted for four weeks, five times per week. VAS was measured in order to measure pain decrease, and grip strength (GS) was measured using a dynamometer. In order to compare within-group differences before and after the intervention, a paired t-test was performed, and in order to compare differences between the two groups, the analysis of covariance (ANCOVA) was used. All statistically significant levels were set at ${\alpha}=0.05$. Results: There were significant differences in changes of VAS and GS within each group before and after the intervention (p<0.01), but there was no significant difference between the two groups. Conclusion: This study applied PNF wrist taping after the application of stretching or PNF RS to patients who complained of pain beyond a sense of discomfort; these interventions resulted in a decrease in pain and an increase in the grip strength of the subjects. Taping and therapeutic techniques using PNF are considered to be usefully applied as one of the programs to improve wrist pain patients' pain and grip strength.