• Title/Summary/Keyword: Wake Effects

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The Beneficial and Adverse Effects of Raloxifene in Menopausal Women: A Mini Review

  • Khorsand, Imaneh;Kashef, Reyhaneh;Ghazanfarpour, Masumeh;Mansouri, Elaheh;Dashti, Sareh;Khadivzadeh, Talat
    • Journal of Menopausal Medicine
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    • v.24 no.3
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    • pp.183-187
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    • 2018
  • Objectives: The present mini review aimed to summarize the existing knowledge regarding the beneficial and adverse effects of raloxifene in menopausal women. Methods: This study is a review of relevant publications about the effects of raloxifene on sleep disorder, depression, venous thromboembolism, the plasma concentration of lipoprotein, breast cancer, and cognitive function among menopausal women. Results: Raloxifene showed no significant effect on depression and sleep disorder. Verbal memory improved with administration of 60 mg/day of raloxifene while a mild cognitive impairment risk reduction by 33% was observed with administration of 120 mg/day of raloxifene. Raloxifene was associated with a 50% decrease in the need for prolapse surgery. The result of a meta-analysis showed a significant decline in the plasma concentration of lipoprotein in the raloxifene group compared to placebo (standardized mean difference, -0.43; 10 trials). A network meta-analysis showed that raloxifene significantly decreased the risk of breast cancer (relative risk, 0.572; 95% confidence interval, 0.327-0.881; P = 0.01). In terms of adverse effects of raloxifene, the odds ratio (OR) was observed to be 1.54 (P = 0.006), indicating 54% increase in the risk of deep vein thrombosis (DVT) while the OR for pulmonary embolism (PE) was 1.05, suggesting a 91% increase in the risk of PE alone (P = 0.03). Conclusions: Raloxifene had no significant effect on depression and sleep disorder but decreased the concentration of lipoprotein. Raloxifene administration was associated with an increased risk of DVT and PE and a decreased risk of breast cancer and pelvic organ prolapse in postmenopausal women.

A Systematic Study of the Intervention Effect of Social Stories in Children with Sleep Disorders (수면장애 아동을 위한 사회적 이야기 중재 효과: 체계적 고찰)

  • Kim, Ji-Ho;Yoo, Eun-Young
    • The Journal of Korean Academy of Sensory Integration
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    • v.21 no.2
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    • pp.69-83
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    • 2023
  • Objective : This study sought to systematically examine the intervention effect of social stories when applied in relation to children with sleep disorders. Methods : Studies available in the SCOPUS, ScienceDirect, PsycArticles, and PubMed databases that were published from 2001 to 2022 were searched. The keywords used for the search were as follows: ("social story" OR "social stories") AND ("sleep" OR "sleep disorders" OR "sleep wake disorder bedtimes" OR "sleep initiation and maintenance disorders" OR "sleep wake disorder" OR "sleep arousal disorders"). Based on the selection criteria, six experimental studies were selected and analyzed. Results : The selected studies were two randomized controlled trials, three individual trials, and one case study. The subjects were mostly children diagnosed with autism spectrum disorder who were school-aged or adolescent. The intervention types were often complex interventions, including social stories and other interventions, while the durations of the interventions varied from one day to more than 40 days. The interventions had a positive effect on the subjects' sleep quality, with night wakings, sleep onset delay, and sleep anxiety all being improved. As standardized assessment tools to evaluate the effectiveness of social stories, the Child Sleep Habits Questionnaire and the Child Behavior Checklist were used in two papers each, and were the most commonly used. As non-standardized assessment tools, each of the four papers used turbulence and sleep diaries as assessment tools. Conclusion : The effect of social story mediation can be divided into sleep quality and sleep-related behavior. In terms of sleep quality, studies showing improvements in night wakings, sleep onset delay, and sleep anxiety accounted for a large proportion of the sample. The detailed effect area of sleep quality showed a significant improvement after the interventions in most studies, and in all six studies analyzed in the present study, the continuation of the effect after the intervention was confirmed via follow-up tests. Thus, the findings of this study are expected to be helpful when applying social stories in children with sleep disorders in clinical practice due to presenting the intervention effects, outcome evaluation tools, and intervention periods in children with sleep disorders in prior investigations involving social stories.

Numerical Analysis on Effects of the Boundary Layer Fence Equipped on the Hub of Rotor in the First Stage Axial Flow Gas Turbine (1단 축류 가스터빈내 동익의 허브면에 장착된 경계층 펜스의 효과에 대한 수치 해석적 연구)

  • Yoon, Deok-Kyu;Kim, Jae-Choon;Kim, Dae-Hyun;Lee, Won-Suk;Chung, Jin-Taek
    • The KSFM Journal of Fluid Machinery
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    • v.12 no.2
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    • pp.8-16
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    • 2009
  • The objective of this study is to investigate the three-dimensional turbulence flow characteristics of a rotor passage of an one-stage axial flow gas turbine and to investigate the effects of a boundary layer fence installed on the hub endwall of the rotor passage. Secondary flows occurring within the rotor passage (e.g. horseshoe vortex, passage vortex, and cross flow) cause secondary loss and reduce turbine efficiency. To control these secondary flows, a boundary layer fence measuring half the height of the thickness of the inlet boundary layer was installed on the hub endwall of the rotor passage. This study was performed numerically. The results show that the wake and secondary flows generated by the stator reduced the rotor load to constrain the development of cross flow and secondary flow reinforced by the rotor passage. In addition, the secondary vortices occurring within the rotor passage were reduced by the rotation of the rotor. Although, the boundary layer fence induced additional vortices, giving rise to an additional loss of turbine, its presence was shown to reduce the total pressure loss when compared to effects of the case without fence regardless of the relative position of blades by enervating secondary vortices occurred within the rotor passage.

Numerical Simulation on Laminar Flow past a Rotating Circular Cylinder (회전하는 원형 주상체 주위의 층류 유동장의 수치 시뮬레이션)

  • MooN JIN-KooK;PARK JONG-CHUN;YOON HYUN-SIK;CHUN HO-HWAN
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2004.05a
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    • pp.222-228
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    • 2004
  • The effects of rotation on the unsteady laminar flow past a circular cylinder is numerically investigated in the present study. We obtained the numerical solutions for unsteady two-dimensional governing equation for the flow using two different numerical schemes. One is an accurate spectral method and another is finite volume method. Above all, the flow around a stationary circular cylinder is investigated to understand the basic phenomenon of flow separation, bluff body wake. Also, the validation of our own codes, expecially based on FVM, is carried out by the comparison of results obtained from our simulations using two different schemes and previous numerical and experimental studies. By the effect of rotation, the mean lift increases and drag deceases, which well represent the previous study.

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A Study on the Heat Transfer Characteristics Around a Surface-Mounted Air-Cooled Module for the Flow Angle-of-Attack (흐름 영각에 따른 강제공랭 모듈 주위의 열전달 특성에 관한 연구)

  • Park, Sang-Hui;Sin, Dae-Jong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.26 no.9
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    • pp.1267-1275
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    • 2002
  • An experimental study was performed to investigate adiabatic wall temperature and heat transfer coefficient around a module cooled by forced air flow. The flow angle of attack to the module were 0$^{\circ}$and 45$^{\circ}$. In the first method, inlet air flow(1~7m/s) and input power.(3, 5, 7W) were varied after a heated module was placed on an adiabatic floor(320$\times$550$\times$1㎣). An adiabatic wall temperature was determinated to use liquid crystal film. In the second method to determinate heat transfer coefficient, inlet air flow(1~7m/s) and the heat flux of rubber heater(0.031~0.062W/$m^2$) were varied after an adiabatic module was placed on rubber heater covering up an adiabatic floor. Additional information is visualized by an oil-film method of the surface flow on the floor and the module. Plots of $T_{ad}$ and $h_{ad}$ show marked effects of flow development from the module and dispersion of thermal wake near the module. Certain key features of the data set obtained by this investigation may serve as a benchmark for thermal-design codes based on CFD.

Effect of Sound Field on the Forced Convection Heat Transfer from an Isothermal Cylinder (음장이 등온원통으로부터의 강제대류 열전달에 미치는 영향)

  • 권영필
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.12 no.2
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    • pp.373-380
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    • 1988
  • The effect of sound on the heat transfer from an isothermal cylinder in cross flow is investigated by numerical analysis. The modeling is made for the laminar incompressible flow fluctuating in the range of the Reynolds number, 5.leq.Re.leq.35, by the sinusoidal acoustic field. The instantaneous response of the flow and heat transfer is simulated for various frequencies. It is shown that the heat transfer amplitude decreases and the phase lags behind the flow velocity with increase in the frequency. The time-mean effects of the acoustic field on the flow field and heat transfer, known as the acoustic and thermoacoustic streaming, are analyzed. The time-mean heat transfer coefficients are decreased around the forward stagnation point but increased in the wake region. Such a local difference in heat transfer coefficients is a function of the frequency and becomes greatest at some frequency. However, with balance between the local increase and decrease, the overall heat transfer coefficient is almost unaffected by sound.

Numerical Study on the Fluid Flow and Heat Transfer Past a Cylinder with a Periodic Array of Circular Fins (원형 핀이 부착된 실린더 주위의 유동 및 열전달에 관한 수치적 연구)

  • Yoon, Hyun-Sik;Chun, Ho-Hwan;Lee, Dong-Hyuk
    • Journal of the Society of Naval Architects of Korea
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    • v.43 no.3 s.147
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    • pp.285-293
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    • 2006
  • Three-dimensional and time-dependent solution for the fluid flow and heat transfer past a circular cylinder with fins is obtained using accurate and efficient spectral methods. A Fourier expansion with a corresponding uniform grid is used along the circumferential direction. A spectral multi-domain method with a corresponding Chebyshev collocation is used along r-z plane to handle fins attached to the surface of a circular cylinder. At the Reynolds number of 300 based on a cylinder diameter, results with fins are compared with those without fins in order to see the effects of the presence of fins on three-dimensional and unsteady fluid flow and heat transfer past a bluff body. The detail structures of fluid flow and temperature field are obtained as a function of time to investigate how the presence of fins changes heat transfer mechanism related to the vortical structure in the wake region.

Whipping analysis of hull girders considering slamming impact loads (슬래밍 충격하중을 고려한 선체 휘핑 해석)

  • Seong-Whan Park;Keun-Bae Lee;Chae-Whan Rim
    • Journal of the Society of Naval Architects of Korea
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    • v.37 no.3
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    • pp.99-109
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    • 2000
  • Elastic dynamic responses analysis program for ship hulls considering slamming impact loads due to the voyage in large amplitude waves is developed. Ship hull structures are modeled by a thin-walled beam model in order to consider effects of shear deformation. The momentum slamming theory is used to derive nonlinear hydrodynamic forces considering intersection between wave particles and ship section. For the validation of the developed computer program, motions of a V-shaped simple section model and S-175 standard container model are calculated and analyzed. In each numerical example, time histories of relative displacement, velocity and vertical bending moment of a ship section are derived, considering the effect of slamming impacts in various wave conditions.ures near the free surface as well as the wake of the hydrofoil.

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SIMULATION OF PARTICLE DISPERSION AND DEPOSITION IN FLOW AROUND TWO CIRCULAR CYLINDERS IN A SIDE-BY-SIDE ARRANGEMENT (병렬로 배열된 두 개의 원형 실린더 유동에서 입자의 분산과 부착 해석)

  • Hwang, Dongjun;Kim, Dongjoo
    • Journal of computational fluids engineering
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    • v.21 no.2
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    • pp.81-89
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    • 2016
  • Numerical simulations are carried out for the fluid flow and particle transport around two nearby circular cylinders in a side-by-side arrangement. The present study aims to understand the effects of the particle Stokes number and the spacing between two cylinders on particle dispersion and deposition characteristics. Simulations are based on an Eulerian-Lagrangian approach where the motion of particles is calculated by a Lagrangian approach based on one-way coupling. Results show that the flow structure is very different depending on the cylinder spacing, eventually affecting the overall pattern of particle dispersion significantly. It is also found that particles with smaller Stokes number tend to be distributed more uniformly in the wake of two cylinders, being located even inside the vortex cores. Meanwhile, particle deposition is analyzed in terms of the deposition efficiency and deposition location. The deposition efficiency of particles strongly depends on the Stokes number, whereas it is slightly affected by the cylinder spacing. The deposition location gets wider as the Stokes number increases, and it becomes asymmetric about the center of each cylinder as the cylinders get close.

A study on the optimal placement model building of artificial reef (인공어초의 최적 배치모델 구축에 관한 연구)

  • SOHN, Byung-Kyu;JEONG, Seong-Jae
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.53 no.2
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    • pp.160-168
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    • 2017
  • In this study, we propose a method of optimal placement technique of artificial reef considering characteristics of sea areas and provide basic data for efficient budget execution. In addition, we will contribute to increasing the economic efficiency by improving the fisheries productivity by suggesting the scientific basis for the policy data and the increase of the catch through the resource creation based on the ecological information about the biology. Especially, in order to establish the effective disposition (optimum separation distance) of artificial reef considering characteristics of biological and engineering factors, it is necessary to review the artificial reef installation management regulations and investigate the biological effects of artificial reef facilities, is needed. Through this, it is expected that the ground data of the direction of the policy promotion will be derived by suggesting the placement condition of the artificial reef complex which can maximize the resource composition effect according to the target fish species.