• Title/Summary/Keyword: FAC

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Effects of alloys and flow velocity on welded pipeline wall thinning in simulated secondary environment for nuclear power plants (원전 2차계통수 모사 환경에서 용접배관 감육 특성에 미치는 재료 및 유속의 영향)

  • Kim, Kyung Mo;Choeng, Yong-Moo;Lee, Eun Hee;Lee, Jong Yeon;Oh, Se-Beom;Kim, Dong-Jin
    • Corrosion Science and Technology
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    • v.15 no.5
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    • pp.245-252
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    • 2016
  • The pipelines and equipments are degraded by flow-accelerated corrosion (FAC), and a large-scale test facility was constructed for simulate the FAC phenomena in secondary coolant environment of PWR type nuclear power plants. Using this facility, FAC test was performed on weld pipe (carbon steel and low alloy steel) at the conditions of high velocity flow (> 10 m/s). Wall thickness was measured by high temperature ultrasonic monitoring systems (four-channel buffer rod type and waveguide type) during test period and room temperature manual ultrasonic method before and after test period. This work deals with the complex effects of flow velocity on the wall thinning in weld pipe and the test results showed that the higher flow velocity induced different increasement of wall thinning rate for the carbon steel and low alloy steel pipe.

Analysis of Key Parameters for Inductively Coupled Power Transfer Systems Realized by Detuning Factor in Synchronous Generators

  • Liu, Jinfeng;Li, Kun;Jin, Ningzhi;Iu, Herbert Ho-Ching
    • Journal of Power Electronics
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    • v.19 no.5
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    • pp.1087-1098
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    • 2019
  • In this paper, a detuning factor (DeFac) method is proposed to design the key parameters for optimizing the transfer power and efficiency of an Inductively Coupled Power Transfer (ICPT) system with primary-secondary side compensation. Depending on the robustness of the system, the DeFac method can guarantee the stability of the transfer power and efficiency of an ICPT system within a certain range of resistive-capacitive or resistive-inductive loads. A MATLAB-Simulink model of a ICPT system was built to assess the system's main evaluation criteria, namely its maximum power ratio (PR) and efficiency, in terms of different approaches. In addition, a magnetic field simulation model was built using Ansoft to specify the leakage flux and current density. Simulation results show that both the maximum PR and efficiency of the ICPT system can reach almost 70% despite the severe detuning imposed by the DeFac method. The system also exhibited low levels of leakage flux and a high current density. Experimental results confirmed the validity and feasibility of an ICPT system using DeFac-designed parameters.

Storm-Time Behaviour of Meso-Scale Field-Aligned Currents: Case Study with Three Geomagnetic Storm Events

  • Awuor, Adero Ochieng;Baki, Paul;Olwendo, Joseph;Kotze, Pieter
    • Journal of Astronomy and Space Sciences
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    • v.36 no.3
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    • pp.133-147
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    • 2019
  • Challenging Minisatellite Payload (CHAMP) satellite magnetic data are used to investigate the latitudinal variation of the storm-time meso-scale field-aligned currents by defining a new metric called the FAC range. Three major geomagnetic storm events are considered. Alongside SymH, the possible contributions from solar wind dynamic pressure and interplanetary magnetic field (IMF) $B_Z$ are also investigated. The results show that the new metric predicts the latitudinal variation of FACs better than previous studies. As expected, the equatorward expansion and poleward retreat are observed during the storm main phase and recovery phase respectively. The equatorward shift is prominent on the northern duskside, at ${\sim}58^{\circ}$ coinciding with the minimum SymH and dayside at ${\sim}59^{\circ}$ compared to dawnside and nightside respectively. The latitudinal shift of FAC range is better correlated to IMF $B_Z$ in northern hemisphere dusk-dawn magnetic local time (MLT) sectors than in southern hemisphere. The FAC range latitudinal shifts responds better to dynamic pressure in the duskside northern hemisphere and dawnside southern hemisphere than in southern hemisphere dusk sector and northern hemisphere dawn sector respectively. FAC range exhibits a good correlation with dynamic pressure in the dayside (nightside) southern (northern) hemispheres depicting possible electrodynamic similarity at day-night MLT sectors in the opposite hemispheres.

The Effect of Closed Kinetic Chain Exercise with FES of the Gluteus Medius on Gait in Stroke (닫힌 사슬운동과 병행된 중간볼기근의 기능적 전기자극이 편마비환자의 보행에 미치는 효과)

  • Lee, Su-Kyoung;Park, Min-Chull;Shim, Je-Myung;Kim, Kyung
    • Journal of the Korean Society of Physical Medicine
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    • v.6 no.1
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    • pp.1-8
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    • 2011
  • Purpose : The purpose of this study was to find out the effect of closed kinetic chain exercise with functional electrical stimulation(FES) of the gluteus medius on gait in stroke. Methods : 30 hemiplegic patients voluntarily participated in this study. Subjects were divided into experimental group(n=15) and control group(n=15). Experimental group was given closed kinetic chain exercise with FES of the gluteus medius and control group was given only closed kinetic chain exercise for 4 weeks. All subjects were measured 10m-walking speed, cadence, functional walking category(FAC) and modified motor assessment scale(MMAS) before and after intervention. Results : In experimental group, gait velocity, cadence, FAC and MMAS showed significant difference between pre and post test(p<.05). In control group, gait velocity, cadence and FAC showed significant difference between pre and post test(p<.05). Before intervention, gait velocity, cadence, FAC and MMAS were not significant difference between experimental group and control group(p>.05), but after intervention, gait velocity, FAC and MMAS were significant difference(p<.05). Conclusion : This study show that closed kinetic chain exercise with functional electrical stimulation(FES) of the gluteus medius is beneficial intervention for increase the wlking ability in stroke.

Health-Related Quality of Life of Breast Cancer Patients in iran: Pooled Analysis using Generalized Estimating Equations

  • Kiadaliri, Aliasghar Ahmad;Bastani, Peivand;ibrahimipour, Hossein
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.3
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    • pp.941-944
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    • 2012
  • Objective: The aim of current study was to evaluate the changes of health-related quality of life (HRQoL) and its clinical, demographic and socioeconomic determinants during chemotherapy and 4 months follow-up in women with breast cancer using a repeated measures framework. Methods and Materials: A double blind cohort study was performed in 100 breast cancer patients given fluorouracil, doxorubicin and cyclophosphamide (FAC) or docetaxel, doxorubicin, cyclophosphamide (TAC) in south of Iran. HRQoL was assessed at baseline, end of chemotherapy and four months thereafter using the QLQ-C30 questionnaire from European Organization for Research and Treatment of Cancer (EORTC). Generalized estimating equations (GEE) was applied for statistical analysis. Results: The mean of age at baseline was $48.5{\pm}10.6$. 70% and 14% of patients were married and smokers, respectively, and 20% suffered from another disease besides breast cancer. The results of GEE showed that after control for baseline scores, the HRQoL significantly improved over time. Although, the patients in FAC group had higher scores than the TAC group, the differences also diminished over time. Smoking, marital status and having child affected some scales of HRQoL. None of other variables were significantly related to HRQoL. Conclusion: Although patients in TAC groups had lower level of HRQoL over 8 months follow up, they experienced faster improvement than the FAC group. This implies that in long-term, improvements in TAC group are higher than FAC. Having children was positively correlated with HRQoL. Generally, there were no demographic and socio-economic differences in HRQoL in these patients between the chemotherapeutic regimens.

Molecular Dynamics Simulation Studies of Benzene, Toluene, and p-Xylene in NpT Ensemble: Thermodynamic, Structural, and Dynamic Properties

  • Kim, Ja-Hun;Lee, Song-Hi
    • Bulletin of the Korean Chemical Society
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    • v.23 no.3
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    • pp.447-453
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    • 2002
  • In this paper we have presented the results of thermodynamic, structural, and dynamic properties of model systems for liquid benzene, toluene and p-xylene in an isobaric-isothermal (NpT) ensemble at 283.15, 303.15, 323.15, and 343.15 K using molecular dynamics (MD) simulation. This work is initiated to compensate for our previous canonical (NVT) ensemble MD simulations [Bull. Kor. Chem. Soc. 2001, 23, 441] for the same systems in which the calculated pressures were too low. The calculated pressures in the NpT ensemble MD simulations are close to 1 atm and the volume of each system increases with increasing temperature. The first and second peaks in the center of mass g(r) diminish gradually and the minima increase as usual for the three liquids as the temperature increases. The three peaks of the site-site gC-C(r) at 283.15 K support the perpendicular structure of nearest neighbors in liquid benzene. Two self-diffusion coefficients of liquid benzene via the Einstein equation and via the Green-Kubo relation are in excellent agreement with the experimental measures. The self-diffusion coefficients of liquid toluene and p-xylene are in accord with the trend that the self-diffusion coefficient decreases with increasing number of methyl group. The friction constants calculated from the force auto-correlation (FAC) function with the assumption that the fast random force correlation ends at time which the FAC has the first negative value give a correct qualitative trends: decrease with increase of temperature and increase with the number of methyl group. The friction constants calculated from the FAC's are always less than those obtained from the friction-diffusion relation which reflects that the random FAC decays slower than the total FAC as described by Kubo [Rep. Prog. Phys. 1966, 29, 255].

Association Between Physical Performance and Bone Mineral Density in Elderly Women (여성 노인에서 운동 수행능력과 골밀도의 관계)

  • Shin, Hwa-Kyung;Cho, Kwang-Ho
    • The Journal of Korean Physical Therapy
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    • v.21 no.4
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    • pp.37-42
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    • 2009
  • Purpose: The purpose of this study was to determine the effect of physical performance on bone mineral density (BMD) in elderly women. Methods: Twenty-one elderly women participated in this study. After testing functional ambulation category (FAC), they were classified into two groups: dependent walking group, those who could not walk independently (FAC 0~2, n=11) and independent walking group those who could walk independently (FAC 3~5, n=10). Outcome measures were: general characteristics, physical performance and BMD. General characteristics included age, body mass index (BMI) and waist-hip ratio. Physical performance included the chair rise test (CRT) and the modified fall efficacy scale (MFES). BMD was represented in the osteoporosis index (OI), T-score and Z-score. BMD was evaluated in calcaneal bone, using OsteoPro. The data was analyzed using SPSS 12.0 software and the Mann-Whitney U test and the Spearman correlation. Results: Age, BMI and waist hip ratio, which all affect BMD, showed no significant differences between groups (p>0.05). But the FAC 3~5 group showed a significantly higher score for CRT, MFES and T-score, compared with the FAC 0~2 group (p<0.05). The T-score was correlated with CRT and MFES scores (p<0.05). Conclusion: There is a positive relationship between physical performance and BMD. Therefore, improved physical performance can have a beneficial effect by reducing osteoporosis in elderly women, considering a positive relationship between physical performance and BMD.

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Study on the Systematic Technology of Promoting Purification for the Livestock Wastewater and Reuse

  • Okada, Yoshiichi;Shim, Jae-Do;Mitarai, Masahumi;Kojima, Takayuki;Gejima, Yoshinori
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 1996.06c
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    • pp.692-700
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    • 1996
  • The objective of this study is to develop a systematic purification plant using the metabolism of aerobic microorganisms. This system is subsequently aerated and continuously removes suspended solids and settling sludges caused by aerating pressure at the bottom of a lower pipe (i.e., Continuous Removal of Suspended solids and Settling sludges, CRSS). The CRSS plants are brought out by introducing fine air bubbles into the liquid phase of a lower pipe in the bio-reactor. These plant uses aeration pipe, with multiple inlets to sweep the floor of bio-reactor tank, instead of the conventional scraper mechanisms. The principal advantage of this system is that it can continuously remove very small or light particles that settles completely within a short time. Once the particles have been floated to the surface, they can be moved into the pipe and collected in the settling tank by sequently aerated pressure. The experimental results shows that about 99.0% of the biochemical oxygen demand(BOD), 99.3% of the suspended solid(SS), 92.3% of the total nitrogen(T-N), 99.0% of the turbidity(TU), 100% of the total coliform(TC)and ammonia was respectively removed during aerobic digestion for 9 days. These result indicates that the CRS S plants are very effective for reduction and deodorization of swine wastewater contaminants, and the efflux from CRS S can either be discharged in the river or used as nutrient solution of formulation for plant growth factories. The developed CRSS plant proved to be flexible and it can simply be adapted to any type of biological waste treatment problem.roblem.

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Reduction of the Flow Accelerated Corrosion within Low Pressure Evaporator Connection Pipe by Interception of Hydrazine for Water Treatment (탈산소제 차단 수처리에 의한 배열회수보일러 저압증기발생기 연결배관내의 유동가속부식 저감)

  • Son, Byung-Gwan;Lee, Jae-Heon
    • Plant Journal
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    • v.9 no.4
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    • pp.26-30
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    • 2013
  • Based on case that HRSG low pressure steam generator tube was damaged by FAC in 500 MW A CCPP. This case analyzed the effect of application about the block of hydrazine water treatment which is applied for increasing dissolved oxygen. And also try to deduce the major factor of FAC Which is caused by lacking of dissolved oxygen of boiler feed system. After 1 year of water treatment, the figure of dissolved oxygen in the boiler feed water has increased from 0.15 ppb to 3~5 ppb and the figure of oxidation reduction potential has increased from -245 mV to 170 mV. And Iron content, the corrosion products by FAC has decreased from 18.5 ppb to 5~7 ppb. According to the result of experiment, we could able to confirm that the interception of hydrazine of water treatment is effective to reduce FAC.

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Several Functional Properties of Freeze-dried Powder of Pre-concentrated Aloe vera gel (농축 전처리된 Aloe vera gel의 동결건조분말의 기능성)

  • Lee, Nam Jae;Lee, Seung Ju
    • Food Engineering Progress
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    • v.13 no.3
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    • pp.216-220
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    • 2009
  • The several functional properties of freeze-dried powder of Aloe vera gel was examined as influenced by pre-concentration degrees of the gel solution. As a pre-treatment prior to freeze drying, the gel solution was vacuum-concentrated by three levels (unit: g-water/g-solids) - high (H), 76; medium (M), 119; low (L), 159. In FT-IR spectra, the sample H showed the highest absorbance in the range of 1600-1550 $cm^{-1}$ and 1450-1400 $cm^{-1}$, which corresponded to level of the acetyl group in glucomannan. The sample H of freeze-dried powder was the highest in polysaccharide content, jack bean urease inhibition rate, and FAC (fat adsorption capacity). It could be inferred that the sample H had an effect on Helicobacter pylori inhibition and fat adsorption suppression according to urease inhibition rate and FAC, respectively.