• Polymer(Korea)
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• v.27 no.1
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• pp.61-68
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• 2003

In this study, we have investigated the preparation of mixed bead and fiber type hybrid ion-exchanger for recovering nickel ion from plating rinse water. There was little dependence of adsorption capacity for nickel ion on the mixing ratio of resin type and fiber type of ion exchangers. However, it increased with increasing the resin content in the mixed bed. It was shown that the data Langmuir and Freundlich's adsorption isotherm model were well fitted to the linear. Affinity between the functional groups in the ion exchanger and nickel ion in the process was confirmed. The pressure drop decreased with increasing the number of stage in the multistage bed, but it increased with increasing the resin content in the mixing bed. The initial breakthrough time in the multistage bed was short due to the increase of number of stage in the continuous process. It was found that the final breakthrough time of the multistage bed was little changed. The breakthrough time decreased with increasing the amount of fibrous ion exchanger in the mixed bed. The maximum adsorption capacities of the mixed and multistage beds were 2.51 meq/g and 2.69 meq/g, respectively. The desorption time for the nickel ion with $1N H_2SO_4$ solution was lower than 10 minutes and the yield of desorption was greater than 98 percent.

• Journal of Life Science
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• v.19 no.5
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• pp.625-632
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• 2009

The purpose of this study was to examine the effect of exercise training on nitric oxide (NO) levels, mean arterial pressure (MAP), blood pressure (BP), and heart rate (HR) in college students. 5 subjects were randomly assigned to two experimental groups; an aerobic training group (ATG) and a resistance training group (RTG). In aerobic training, based on measured maximum oxygen consumption rate, 70% exercise intensity was applied and conducted for 60 min. In resistance training, 70% of 1-RM was performed for 90 min. Blood sampling was conducted 3 times during resting state, post-exercise, and after 30 minutes of recovery. The results are as followed. For the post training values of $VO_2max$, % body fat and MAP, there were significant differences in the ATG compared to pre training (p<0.05). However, there were no differences in the RTG between pre and post training. NO increased post training, during rest and at the end of exercise compared to pre training in the ATG (p<0.05). Also, the HR decreased in post training at the end of exercise (p<0.05), however, there were no significant differences in SBP and DBP between pre and post training in the ATG. The HR, SBP and DBP did not change at all in post training compared to pre training in the RTG. In conclusion, an increase in the production of Nitric Oxide (NO) concentration and $VO_2max$, decrease of body fat% and physiological variables (HR, BP, MAP) were shown to be more effective in aerobic training (AT) than resistance training (RT).

• Journal of Korean Society of Environmental Engineers
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• v.33 no.1
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• pp.47-53
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• 2011

$SF_6$ (Sulfur hexafluoride) possesses high GWP (Global Warming Potential) as sepcified by the IPCC (Intergonvernmental Panel of Climate Change). Recently, the recovery-separtion of $SF_6$ research area, including permeation properties studies using various membrane's materials and the practical operation of recovery-separtion using membrane of waste $SF_6$ gas is in the initial state. The separation efficiency of a single $SF_6$ and waste $SF_6$ mixture was evaluated using a PSF (polysulfone), PC (tetra-bromo polycarbonate) and PI (polyimide) hollow fiber membranes. According to the results of single gases permeation properties, PI membrane has the highest permselectivity of $N_2$ gas in $N_2/SF_6$ gas. Under the condition of P=0.5 MPa, the highest concentration of recovered $SF_6$ is 95.6 vol % in the separation experiment of $SF_6/N_2$ mixture gas by PC membrane. Under the operation pressure of P=0.3 MPa at a fixed retentate flow rate fixed of 150 cc/min, the maximum recovery efficiency of $SF_6$ is up to 97.8% by PSF membrane. From the results above, it is thought that the separation and recovery technique of $SF_6$ gas using membrane will be used as the representative eco-technology in the $SF_6$ gas treatment in the future.

• Journal of Energy Engineering
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• v.6 no.1
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• pp.104-113
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• 1997

This study aims to develop an analysis model using a commercial process simulator-ASPEN PLUS for an IGCC (Integrated Gasification Combined Cycle) system consisting a dry coal feeding, oxygen-blown entrained gasification process by Shell, a low temperature gas clean up process, a General Electric MS7001FA gas turbine, a three pressure, natural recirculation heat recovery steam generator, a regenerative, condensing steam turbine and a cryogenic air separation unit. The comparison between those results of this study and reference one done by other engineer at design conditions shows consistency which means the soundness of this model. The greater moisture contents in Illinois#6 coal causes decreasing gasifier temperature and the greater ash and sulfur content hurt system efficiency due to increased heat loss. As the results of sensitivity analysis using developed model for the parameters of gasifier operating pressure, steam/coal ratio and oxygen/coal ratio, the gasifier temperature increases while combustible gases (CO＋H2) decreases throughout the pressure going up. In the steam/coal ratio analysis, when the feeding steam increases the maximum combustible gas generation point moves to lower oxygen/coal ratio feeding condition. Finally, for the oxygen/coal ratio analysis, it shows oxygen/coal ratio 0.77 as a optimum operating condition at steam/coal feeding ratio 0.2.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.179.1-179.1
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• 2011

Pretreatment of cellulosic biomass is necessary before enzymatic saccharification and fermentation. The objective of this study was to evaluate the effect of combined aqueous ammonia-dilute sulfuric acid treatment on cellulosic biomass. Miscanthus was pretreated using aqueous ammonia and dilute sulfuric acid solution under high temperature and pressure conditions to be converted into bioethanol. Aqueous ammonia treatment was performed with 15 %(w/w) ammonia solution at $150^{\circ}C$ of reaction temperature and 20 minutes of reaction time. And then, dilute sulfuric acid treatment was performed with 1.0 %(w/w) sulfuric acid solution at $150^{\circ}C$ of reaction temperature and 10 minutes of reaction time. The compositional variations of this combined aqueous ammonia-dilute sulfuric acid treatment resulted in 68.0 % of cellulose recovery and 95.7 % of hemicellulose, 81.3 % of lignin, 89.1 % of ash removal respectively. The enzymatic digestibility of 90.5 % was recorded in the combined pretreated Miscanthus sample and it was 14.7 times higher than the untreated sample. The ethanol yield in the Simultaneous Saccharification and Fermentation was 90.4 % of maximum theoretical yield based on cellulose content of the combined pretreated sample and it was about 98 % compared to the ${\alpha}$-cellulose ethanol yield.

• Water for future
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• v.26 no.1
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• pp.63-69
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• 1993

Remediation technology becomes an issue in environmental engineering. The vibro-recovery technique is one of popular means to remove pollutants from contaminated soils and groundwater. Using Ultrasonic excitation in soil-fluid medium, it was found that removal efficiency in a mechanical effects was significant. In this paper, therefore, laboratory experiments were conducted on clayey sand soil columns using a probe-type ultrasonic processor. Ultrasonic treatment with simultaneous pumping enhances dislodgement of clay particles, and ultrasonic excitation reduced the proportions of finer particles and thus result in increased hydraulic conductivity significantly. Also, the results provided the changes in grain size distribution curve of the soil due to ultrasonic excitation. The results indicated that the maximum size of particles mobilized by Ultrasonic is about 0.004mm and particles in the size range from 0.04mm to 1.0mm were subjected to fracturing. The economic feasibility of Ultrasonic implementation is considered in power requirement of the generator and maintenance of the horn. At a specified amplitude of vibrations, the power requirement of the generator depends on overburden pressure of the horn, temperature and viscosity of fluid in the soil medium. For comparisons, the requirement of a one inch and two inch diameter horn sonicators are compared with the power required for pumping water from different depths.

• Physical Therapy Rehabilitation Science
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• v.5 no.1
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• pp.34-39
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• 2016

Objective: Hip abductors play a role in providing stability and movement to the lower limbs. The purpose of this study was to examine the effects of hip abductor fatigue on static balance and gait in the general population. Design: One group pre-test post-test design. Methods: Thirteen university students in their twenties volunteered for the study and had underwent a functional assessment. To induce fatigue, the subjects were instructed to raise their dominant lower extremity up against a load of 50% of 1 repetition maximum while producing hip abduction in a side-lying position. Subjects were instructed to maintain an abduction speed of 30 repetitions per minute to induce fatigue. Muscle fatigue was considered to be established when subjects were unable to perform hip abduction three consecutive times along with the metronome. A post-test of balance and gait was performed immediately in order to prevent fatigue recovery. The center of pressure (COP) distance area was measured using the Zebris FDM-S Multifunction Force measuring plate. Gait performance was analyzed using the GAITRite. Results: The COP distance was increased after fatigue was induced. There was a significant increase in the standard deviation of the medio-lateral and antero-posteror distance (p<0.05). Although there was no significant difference in gait parameters, there was a significant decrease in single support time after fatigue was induced (p<0.05). Conclusions: There was an increase in static balance instability and a significant decrease in single support time during gait due to hip abductor muscle fatigue.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.4
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• pp.371-375
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• 1988

Tubular ultrafiltration membranes were used to investigated mass transfer characteristics of waste cheese whey. The effects of bulk concentration and flow velocity on permeat flux, mass transfer coefficient and apparent rejection coefficient were measured. Mass transfer coefficient was increased linearly with increasing flow velocity, and following relationship between mass transfer coefficient(k) and linear velocity(u) was obtained. $k=0.87{\times}10^{-5}u^{1-1}$ It is interjecting to note that plots for all linear velocity tend to converge to the same point for zero permeating flux, and the maximum bulk concentration that can be achieved with cheese whey extracts was 38(w/v %). In general, membrane rejection coefficient increased with increasing flow velocity and the rejection coefficients of cheese whey solution and that of lactose in cheese whey solution were obtained $0.40{\sim}0.65$, $0.15{\sim}0.30$, respectively.

• Applied Biological Chemistry
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• v.37 no.1
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• pp.14-18
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• 1994

In order to elucidate the interaction effect between temperature and moisture content on the oil expression of perilla seed, recovery of expressed oil (REO) and volumetric strain of pressed cake (VSPC) of both roasted and unroasted perilla seeds were observed at different temperatures of 30, 40, 50 and $60^{\circ}C$, and different moisture contents of 2.5, 4.5, 6.5 and 8.5% (w.b). And duration of press was 11 min and applied pressure was 50 MPa. At the low temperature REO and VSPC of roasted and unroasted perilla seed increased in high moisture content and at the high temperature those increased in low moisture content. But REO and VSPC at 8.5% moisture content were decreased without relation to temperature. From the analysis of variance between expression factors and REO and VSPC, temperature and moisture contents showed high significance. Also the interaction effect between temperature and moisture content was higher than temperature. In our experimental conditions, the highest interaction effect between expression factors was observed in the range of $2.5{\sim}4.5%$ of moisture content in all temperatures. The maximum REO of unroasted perilla seeds was observed as 84.4% at 2.5% of moisture content and $60^{\circ}C$, and that of roasted one was as 84.3% at 6.5% of moisture content and $30^{\circ}C$.

• Women's Health Nursing
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• v.8 no.3
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• pp.412-423
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• 2002

This study was designed to evaluate the effect of pelvic floor muscle exercise using biofeedback and electrical stimulation after normal vaginal delivery. The data were collected from November 1999 to April 2000 at a university hospital located in Seoul, Korea. Out of 49 women with normal vaginal delivery, 25 of experimental group(with exercise) and 24 of control group(without exercise) were questioned about lower urinary symptoms, discomfort during sexual intercourse and daily life. The maximum pressure of pelvic floor muscle contraction(MPPFMC) and duration of pelvic floor muscle contraction(DPFMC) were measured at pre-treatment, the end of treatment and 8 weeks after a treatment program. The pelvic floor muscle exercise program(using biofeedback and electrical stimulation) was applied to the experimental group twice a week for 4 weeks at the incontinence clinic and the pelvic floor muscle exercise at home for that time and more 8 weeks. Data were analyzed by t-test, $x^2$-test, Fisher's exact test and the repeated measures ANOVA. The results were as follows; 1) MPPFMC(p=0.000) and DPFMC(p=0.021) were significantly increased in the experimental group. 2) In the lower urinary symptoms, daily frequency(p=0.001), nocturia(p=0.002), incontinence episode(p=0.016), stress incontinence(p=0.012), quantity of incontinence(p=0.026), straining(p=0.041), and strength of stream(p=0.009) were significantly decreased in the experimental group. 3) Discomfort during sexual intercourse had not a significant difference between the two groups, which was not significantly decreased as time passed. 4) In the discomfort during daily life, activity restriction(p=0.042), exercise restriction (p=0.008), interpersonal relationship restriction(p=0.046), and discomfort of general life(p=0.027) showed a significant difference between the two groups, which were not significantly decreased as time passed. In conclusion, it is suggested that the pelvic floor muscle exercise using biofeedback and electrical stimulation might be a safer and more effective program for the improvement of postpartum pelvic muscle contraction.