• 대한통합의학회지
• /
• 제9권1호
• /
• pp.151-161
• /
• 2021

Purpose : This study was to investigate the effectiveness of ESWT and plantar fascia-specific stretching exercise vs ESWT and high-load strengthening exercise in patients with chronic plantar fasciitis. Methods : The subjects were randomized to extracorporeal shock wave therapy ( ESWT, for 3 weeks) and daily plantar-specific stretching (Group I: Stretch group) or ESWT and high-load progressive strength (Group II: Strength group) performed every second day. The main outcome measures were ultrasound, visual analogue scale (VAS), and Korean Foot Function Index (KFFI). The ultrasound (plantar fascia thickness), pain intensity I, II (the most painful of the day?, the pain when you first step in the morning?) and KFFI (functional performance) were compared between the groups. Results : No significant difference was observed between the groups in the plantar fascia thickness but pain intensity I, II was significantly lower in Group 2 than in Group 1 at only 12weeks and functional performance was also significantly increased in Group 2 compared to Group 1 at only 12 weeks. Conclusion : The high-load strengthening exercise consisting of the progressive exercise protocol, resulted in superior after 12 weeks compared with plantar-specific stretching. High-load strength exercise may aid in a quicker reduction in pain and improvements in functional performance.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2008년도 학술대회
• /
• pp.367-373
• /
• 2008

Spinning detonations propagating in a circular tube were numerically investigated with a one-step irreversible reaction model governed by Arrhenius kinetics. Activation energy is used as parameter as 10, 20, 27 and 35, and the specific heat ratio and the heat release are fixed as 1.2 and 50. The time evolution of the simulation results was utilized to reveal the propagation mechanism of single-headed spinning detonation. The track angle of soot record on the tube wall was numerically reproduced with various levels of activation energy, and the simulated unique angle was the same as that of the previous reports. The maximum pressure histories of the shock front on the tube wall showed stable pitch at Ea=10, periodical unstable pitch at Ea=20 and 27 and unstable pitch consisting of stable, periodical unstable and weak modes at Ea=35, respectively. In the weak mode, there is no Mach leg on the shock front, where the pressure level is much lower than the other modes. The shock front shapes and the pressure profiles on the tube wall clarified the mechanisms of these stable and unstable modes. In the stable pitch at Ea=10, the maximum pressure history on the tube wall remained nearly constant, and the steady single Mach leg on the shock front rotated at a constant speed. The high and low frequency pressure oscillations appeared in the periodical unstable pitch at Ea=20 and 27 of the maximum pressure history. The high frequency was one cycle of a self-induced oscillation by generation and decay in complex Mach interaction due to the variation in intensity of the transverse wave behind the shock front. Eventually, sequential high frequency oscillations formed the low frequency behavior because the frequency behavior was not always the same for each cycle. In unstable pitch at Ea=35, there are stable, periodical unstable and weak modes in one cycle of the low frequency oscillation in the maximum pressure history, and the pressure amplitude of low frequency was much larger than the others. The pressure peak appeared after weak mode, and the stable, periodical unstable and weak modes were sequentially observed with pressure decay. A series of simulations of spinning detonations clarified that the unsteady mechanism behind the shock front depending on the activation energy.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2008년 추계학술대회논문집
• /
• pp.367-373
• /
• 2008

Spinning detonations propagating in a circular tube were numerically investigated with a one-step irreversible reaction model governed by Arrhenius kinetics. Activation energy is used as parameter as 10, 20, 27 and 35, and the specific heat ratio and the heat release are fixed as 1.2 and 50. The time evolution of the simulation results was utilized to reveal the propagation mechanism of single-headed spinning detonation. The track angle of soot record on the tube wall was numerically reproduced with various levels of activation energy, and the simulated unique angle was the same as that of the previous reports. The maximum pressure histories of the shock front on the tube wall showed stable pitch at Ea=10, periodical unstable pitch at Ea=20 and 27 and unstable pitch consisting of stable, periodical unstable and weak modes at Ea=35, respectively. In the weak mode, there is no Mach leg on the shock front, where the pressure level is much lower than the other modes. The shock front shapes and the pressure profiles on the tube wall clarified the mechanisms of these stable and unstable modes. In the stable pitch at Ea=10, the maximum pressure history on the tube wall remained nearly constant, and the steady single Mach leg on the shock front rotated at a constant speed. The high and low frequency pressure oscillations appeared in the periodical unstable pitch at Ea=20 and 27 of the maximum pressure history. The high frequency was one cycle of a self-induced oscillation by generation and decay in complex Mach interaction due to the variation in intensity of the transverse wave behind the shock front. Eventually, sequential high frequency oscillations formed the low frequency behavior because the frequency behavior was not always the same for each cycle. In unstable pitch at Ea=35, there are stable, periodical unstable and weak modes in one cycle of the low frequency oscillation in the maximum pressure history, and the pressure amplitude of low frequency was much larger than the others. The pressure peak appeared after weak mode, and the stable, periodical unstable and weak modes were sequentially observed with pressure decay. A series of simulations of spinning detonations clarified that the unsteady mechanism behind the shock front depending on the activation energy.

• 대한통합의학회지
• /
• 제9권4호
• /
• pp.237-249
• /
• 2021

Purpose : This study was to compare the effect changes after physical therapy (extracorporeal shock wave therapy + high-load strengthening exercise) or corticosteroid injection in patients diagnosed with chronic plantar fasciitis. Methods : A total of 40 patients were randomly assigned to each group of 20. According to the intervention method, "Group 1. Physiotherapy" was performed for 12 weeks, and "Group 2. Corticosteroid injection" was performed only once. As a pre-intervention test, plantar fascia thickness, pain intensity I, II (What is the most painful moment of the day?, How painful is the first step in the morning?), and functional performance were measured. To compare the effects of each group, the tests 3, 6, and 12 weeks after were also performed using the same measurement method. Also, after 12 weeks, patient satisfaction was also compared. Results : There was no significant difference between the groups in the change in the thickness of the plantar fascia during all periods. However, pain intensity I, II was significantly lower in Group 1 than in Group 2 at only 12 weeks and functional performance was also significantly increased in Group 1 compared to Group 2 at only 12 weeks. Also, there was no significant difference between groups in patient satisfaction. Conclusion : The physiotherapy protocol, which consisted of extracorporeal shock wave therapy and high-load strengthening exercise, showed excellent results, especially after 12 weeks, compared to corticosteroid injection. It is recommended as a more effective treatment method as it is possible to safely return to daily life by reducing pain and improving functional performance.

• 천문학회지
• /
• 제50권6호
• /
• pp.157-165
• /
• 2017

$H_2O$ maser emission at 22 GHz in the circumstellar envelope is one of the good tracers of detailed physics and kinematics in the mass loss process of asymptotic giant branch stars. Long-term monitoring of an $H_2O$ maser spectrum with high time resolution enables us to clarify acceleration processes of the expanding shell in the stellar atmosphere. We monitored the $H_2O$ maser emission of the semi-regular variable R Crt with the Kagoshima 6-m telescope, and obtained a large data set of over 180 maser spectra over a period of 1.3 years with an observational span of a few days. Using an automatic peak detection method based on least-squares fitting, we exhaustively detected peaks as significant velocity components with the radial velocity on a $0.1kms^{-1}$ scale. This analysis result shows that the radial velocity of red-shifted and blue-shifted components exhibits a change between acceleration and deceleration on the time scale of a few hundred days. These velocity variations are likely to correlate with intensity variations, in particular during flaring state of $H_2O$ masers. It seems reasonable to consider that the velocity variation of the maser source is caused by shock propagation in the envelope due to stellar pulsation. However, it is difficult to explain the relationship between the velocity variation and the intensity variation only from shock propagation effects. We found that a time delay of the integrated maser intensity with respect to the optical light curve is about 150 days.

• 한국전문물리치료학회지
• /
• 제28권1호
• /
• pp.53-58
• /
• 2021

Background: To evaluate whether extracorporeal shock wave therapy (ESWT) in the pain point is a more effective treatment than the trigger point for myofascial pain syndrome (MPS) of the upper trapezius. Objects: The purpose of this study was to compare the most effective areas when applying extracorporeal shock wave therapy. Methods: A total of 30 patients with MPS were randomly assigned to the trigger point in the ESWT (n = 15) and pain point ESWT (n = 15) groups. Interventions in both groups were performed in one session, i.e., 2,000 shocks with 1.5 bar intensity. Pain and function were assessed using the visual analog scale (VAS) and cervical range of motion (ROM) and based on mechanical muscle properties. Statistical analysis was performed using the repeated measures two-way analysis of variance to determine the significance probability between pre- and post-test. Results: Changes in mechanical muscle properties were not statistically significant between the two groups. However, VAS and cervical ROM showed statistically significant differences at pre- and post-intervention, regardless of the group (p < 0.05). Conclusion: Although no significant difference was observed in the intervention effect, applying an extracorporeal shock wave to the pain point rather than the pain trigger point should be considered in order to save time in effectively and accurately identifying the pain trigger point and site.

• 대한기계학회논문집A
• /
• 제28권6호
• /
• pp.693-700
• /
• 2004

The probabilistic fracture mechanics(PFM) is a useful analytical tool to assess the integrity of reactor pressure vessel(RPV) at the event of pressurized thermal shock(PTS). In PFM, the probabilities of flaw initiation and propagation are estimated by comparing the applied stress intensity factor with the fracture toughness calculated by the simulation of various stochastic variables. It is known that the results of PFM analyses are dependent on the choice of the stochastic parameters and assumptions. Of the various variables and assumptions, we investigated the effects of the RT$_{NDT}$ shift equations, fracture toughness curves, and flaw distributions on the PFM results for the three PTS transients. The results showed that the combined effects of the RT$_{NDT}$ shift equations and fracture toughness curves are complicated and dependent on the characteristics of the transients, the chemistry of the materials, the fast neutron fluence, and so on.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 추계학술대회논문집A
• /
• pp.286-291
• /
• 2000

The reactor pressure vessel is usually cladded with stainless steel to prevent corrosion and radiation embrittlement, and number of subclad cracks have been found during an in-service-inspection. Therefore assessment for subclad cracks should be made for normal operating conditions and faulted conditions such as PTS. Thus, in order to find the optimum fracture assessment procedures for subclad cracks under a pressurized thermal shock condition, in this paper, three different analyses were performed, ASME Sec. XI code analysis, an LEFM(Liner elastic fracture mechanics) analysis and an EPFM(Elastic plastic fracture mechanics) analysis. The stress intensity factor and the Maximum $RT_{NDT}$ were used for characterizing. Analysis based on ASME Sec. XI code does not completely consider the actual stress distribution of the crack surface, so the resulting Maximum allowable $RT_{NDTS}$ can be non-conservative, especially for deep cracks. LEFM analysis, which does not consider elastic-plastic behavior of the clad material, is much more non-conservative than EPFM analysis. Therefore, It is necessary to perform EPFM analysis for the assessment of subclad cracks under PTS.

• 대한기계학회논문집A
• /
• 제25권2호
• /
• pp.275-282
• /
• 2001

The reactor pressure vessel is usually cladded with stainless steel to prevent corrosion and radiation embrittlement. Number of subclad cracks may be found during an in-service-inspection due to the presence of cladding. It is specified, in ASME Sec. XI, that a subclad crack is characterized as a surface crack when the thickness of the clad is less than 40% of the crack depth. This condition is provided to keep the crack integrity evaluation conservative. In order to refine the fracture assessment procedures for such subclad cracks under a pressurized thermal shock condition, three dimensional finite element analyses are applied for various subclad cracks existing under cladding. A total of 36 crack geometries are analyzed, and the results are compared with those for surface cracks. The resulting stress intensity factors for subclad cracks are 6 to 44% less than those for surface cracks. It is proven that the flaw characterization condition as specified in ASME Sec. XI can be overly conservative for some subclad cracks.

• Advances in aircraft and spacecraft science
• /
• 제10권3호
• /
• pp.203-222
• /
• 2023

The detonation combustion is a supersonic combustion process follows on shock wave oscillations in detonation tube. In this paper numerical studies are carried out combined effect of blockage ratio and spacing of obstacle on detonation wave propagation of hydrogen-air mixture in pulse detonation combustor. The deflagration to detonation transition of stoichiometric (ϕ=1)fuel-air mixture in channel has been analyzed for effect of blockage ratio (BR)=0.39, 0.51, 0.59, 0.71 with spacing of 2D and 3D. The reactive Navier-Stokes equation is used to solve the detonation wave propagation mechanism in Ansys Fluent platform. The result shows that fully developed detonation wave initiation regime is observed near smaller vortex generator ratio of BR=0.39 inside the combustor. The turbulent rate of reaction has also a great significance role for shock wave structure. However, vortices of rapid detonation wave are appears near thin boundary layer of each obstacle. Finally, detonation combustor demonstrates the superiority of pressure gain combustor with turbulent rate of reaction of 0.6 kg mol/m3 -s inside the detonation tube with obstacle spacing of 12 cm, this blockage enhanced the turbulence intensity and propulsive thrust. The successful detonation wave propagation speed is achieved in shortest possible time of 0.031s with a significance magnitude of 2349 m/s, which is higher than Chapman-Jouguet (C-J) velocity of 1848 m/s. Furthermore, stronger propulsive thrust force of 36.82 N is generated in pulse time of 0.031s.