• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.1
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• pp.31-38
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• 1999

Adsorption of polymeric flocculants and dry strength agents onto the surface of papermaking fibers is critical for their effective utilization since the polymeric substances not adsorbed on fibers or fines keep recirculating in the papermaking system to cause various operational difficulties and loss of raw materials. Problems associated with the unadsorbed polymeric substances generate great attention because unprecedent interests in utilization of recycled papers and papermaking system closure. In this study, to understand the effects of recycling on the adsorption propensity of cationic polyacryamide (PAM) dry strength resin onto hardwood bleached kraft pulp fibers and fines a systematic approach was followed. Never dried bleached hardwood kraft pulp was recycled in two different ways. In mode one recycling experiment never dried pulp was beaten then recycled three times by employing simple drying and disintegrating steps. In mode two recycling experiment beating of the recycled pulp was carried out after each recycling step. Adsorption of cationic PAM on fibers and fines was evaluated employing Kjeldahl nitrogen analysis method. The influence of recycling on water retention value, carboxyl content, sheet density and tensile strength of the pulp was examined. As the number of recycling increased, water retention value of the fiber was reduced due to hornification and this in turn caused a decrease in adsorption of cationic PAM. On the other hand, the carboxyl content of the recycled fibers increased because of the oxidation of fibers occurred during drying, and this caused an increase in adsorption of cationic PAM. Because of these two opposing factors the adsorption of the cationic PAM on the recycled fibers decreased and then increased slightly at third recycling step. Increase of PAM adsorption, however, did not provide did not provide and strength improvement for the recycled pulp fibers indicating greater influence of the honification on interfiber bonding.

• Journal of the Korean GEO-environmental Society
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• v.15 no.4
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• pp.13-27
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• 2014

Catchments soil erosion, one of the most serious problems in the mountainous environment of the world, consists of a complex phenomenon involving the detachment of individual soil particles from the soil mass and their transport, storage and overland flow of rainfall, and infiltration. Sediment size distribution during erosion processes appear to depend on many factors such as rainfall characteristics, vegetation cover, hydraulic flow, soil properties and slope. This study involved laboratory flume experiments carried out under simulated rainfall in a 3.0 m long ${\times}$ 0.8 m wide ${\times}$ 0.7 m deep flume, set at $17^{\circ}$ slope. Five experimental cases, consisting of twelve experiments using three different sediments with two different rainfall conditions, are reported. The experiments consisted of detailed observations of particle size distribution of the out-flow sediment. Sediment water mixture out-flow hydrograph and sediment mass out-flow rate over time, moisture profiles at different points within the soil domain, and seepage outflow were also reported. Moisture profiles, seepage outflow, and movement of overland flow were clearly found to be controlled by water retention function and hydraulic function of the soil. The difference of grain size distribution of original soil bed and the out-flow sediment was found to be insignificant in the cases of uniform sediment used experiments. However, in the cases of non-uniform sediment used experiments the outflow sediment was found to be coarser than the original soil domain. The results indicated that the sediment transport mechanism is the combination of particle segregation, suspension/saltation and rolling along the travel distance.

• Analytical Science and Technology
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• v.10 no.6
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• pp.408-417
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• 1997

Normal phase or reversed phase liquid chromatographic separation of some structural isomers of functionalized heterocyclic compounds has been carried out by using several different columns and various mobile phases. The optimal experimental conditions for separation of structural isomers were found on a ternary solvent system including alcohol as a modifier. This polar modifier is preferentially adsorbed onto strong adsorption site, leaving a more uniform population of weaker site that then serve to retain the sample. This 'deactivation' of the adsorbent leads to a number of improvements in subsequent separations. The optimal mobile phase system of separation were found on normal phase on structural isomers. Retention mechanism of normal phase system was also studied depending on adsorption strength between solute and stationary phase of column. However, retention factors of reversed phase system were found on hydrophobic interaction with solvophobic effect.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.181-192
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• 1997

The difficulty of endodontic retreatment depends on various factors and it is affected by retention of post. In this experiment, root canal therapy was done in extracted human teeth and cut into 10mm length from the root apex, and then cemented by zinc phosphate cement, Vitremer$^{(R)}$(glass ionomer) luting cement and Panavia 21$^{(R)}$(resin cement). Post preparation was done by #4 Parapost drill at 6mm length and cement was inserted by lentulo spiral. After 24 hours, tensile bond strength, post removal time was measured after the ultrasonic application and the separation site was measured. The following results were obtained. 1. In measuring tensile bond strength, there is no statistical difference between zinc phosphate cement and Panavia 21$^{(R)}$, but Vitremer$^{(R)}$ showed lower value compared with those two cements. (p<0.001) 2. When the post removal time was measured after ultrasonic application, significant different value in order of Panavia 21$^{(R)}$, zinc phosphate cement and Vitremer$^{(R)}$ was shown. (p<0.001) 3. As a result of examining the separating site of each cement, all 16 of zinc phosphate cement group showed the fracture site between cement and post, Vitremer$^{(R)}$ was 13/16, and Panavia 2$^{(R)}$ was 8/16. In case of tooth restoration using Parapost, the use of Panavia 21 showed good retention property than Vitremer$^{(R)}$, but when retreatment is needed the difficulty of post removal will be increased.

• Preventive Nutrition and Food Science
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• v.15 no.1
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• pp.24-29
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• 2010

This study was conducted to investigate sodium and potassium balances, as well as correlations among the relating factors in adult males and females. We collected blood, urine and feces samples as well as a dietary intake survey from 50 subjects. Then, we analyzed the sodium and potassium contents in blood, urine and feces, and evaluated their state of balance. The average ages of the study targets were 24.7 years old for males and 22.8 years old for females. The daily energy intake by the males was 1733.4 kcal and by the females was 1570.3 kcal. Sodium intakes were 138.3 mEq and 127.5 mEq for males and females, respectively. Potassium intakes were 43.1 mEq and 49.3 mEq, respectively. The daily excretions of sodium through urine were 136.6 mEq by males and 97.0 mEq by females and the excretions through feces were 2.2 mEq and 2.0 mEq, respectively. The daily excretions of potassium through urine were 20.2 mEq and 16.5 mEq by males and females respectively, and the excretions through feces were 7.7 mEq and 7.5 mEq male to female. The retention rates of sodium were 11.7% and 14.1% male to female, respectively, and the apparent absorption rates were 98.5% and 97.8%. Additionally, the retention rates of potassium were 32.9% and 39.8% and the apparent absorptions were 81.9% and 81.3%, both male and female. It was noted that, overall, the sodium intake of adult males and females is still higher than the recommended daily sodium intake, while the potassium intakes and excretions were found to be lower. Based on the results of this study, nutritional guidance and education is recommended to encourage decreased sodium intake and increased potassium intake, according to recommended standards.

• Food Science of Animal Resources
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• v.33 no.2
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• pp.221-228
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• 2013

This study was performed to evaluate the effects of various levels of mungbean flour (MF) (0-2.4%) on the quality characteristics of pork model sausages (PMS) in experiment 1 and also select the optimum level of MF to enhance the water retention and gelling properties of low-salt PMS (LSPMS) with or without microbial transglutaminase (MTGase) in experiment 2. In experiment 1, the addition of MF did not affect pH, chemical compositions (fat and moisture contents), color values, and functional properties (expressible moisture, EM (%) and cooking yield, CY (%)) of PMS. However, the addition of MF increased the chewiness of PMS and hardness if the mungbean flour at the level of more than 1.2% was incorporated. Since the interaction between the microbial transglutaminase (MTGase) treatment and MF level was not significant (p>0.05), data were pooled by different factors (MTGase treatment and MF level) in experiment 2. MF improved the water binding ability and textural springiness of LSPMS. On the other hand, MTGase treatment decreased the pH and cooking yield (%) of LSPMS, but increased most textural properties. In conclusion, the addition of MF could enhance the water retention and textural properties of PMS and LSPMS, regardless of MTGase, when it was added to over 1.2%. Based on these results, mungbean protein may interact with MTGase on the low-salt comminuted meat systems. Therefore, further study might be needed to understand the mechanisms of interaction between MTGase and functional components induced from MF.

• Journal of Environmental Science International
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• v.16 no.10
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• pp.1169-1177
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• 2007

The main objective of this research was to evaluate the effects of process variables which were forming ability, flow displacement, effective stress, effective strain, fluid vector and products defects on manufactured artificial lightweight aggregate made of both incinerated sewage sludge ash and clay by means of the numerical analysis of a rigid-plastic finite element method. CATIA (3D CAD program) was used for an extrusion metal mold design that was widely used in designing aircraft, automobile and metallic molds. A metal forming analysis program (ATES Co.) had a function of a rigid-plastic finite element method was used to analyze the program. The result of extrusion forming analysis indicated clearly that a shape retention of the manufactured artificial light-weight aggregate could be maintained by increasing the extrusion ratio (increasing compressive strength inside of extrusion die) and decreasing the die angle. The stress concentration of metal mold was increased by increasing an extrusion ratio, and it was higher in a junction of punch and materials, friction parts between a bottom of the punch and inside of a container, a place of die angle and a place of die of metal mold. Therefore, a heat treatment as well as a rounding treatment for stress distribution in the higher stress concentration regions were necessary to extend a lifetime of the metallic mold. A deformity of the products could have made from several factors which were a surface crack, a lack of the shape retention and a crack of inside of the products. Specially, the surface crack in the products was the most notably affected by the extrusion ratio.

• Journal of Environmental Health Sciences
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• v.35 no.1
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• pp.64-70
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• 2009

The aims of this study is to examine the effects of the changes in HRT(Hydraulic Retention Time) and media charge in a water-mill, among other operation factors, on the nitrogen and phosphorus removal in order to use up-flow anaerobic reactors, anoxic reactors and water-mill aerobic reactors for sewage treatment. The extension of HRT improved the nitrogen removal efficiency, however the removal pattern was constant regardless of HRT. The removal of phosphorus was constant (80%-90%) regardless of the change in HRT. The removal rate with change in influx load varied such that at the OLR (Organic Load Rate) of 1-3 kg/d, the T-N removal efficiency was 80.7%-88.9% and the T-P removal efficiency was 82.9%-89.3% while at the NLR (Nitrogen Loading Rate) of 0.108-0.156 kg/d the removal efficiencies were 80.7-88.9% (T-N) and 82.9-89.3% (T-P). The analyses of the nitrogen and phosphorous removal characteristics with the C/N and C/P ratio showed that the mean T-N removal rate was 88% at the C/N ratio of 1.2-2.6, and that the mean T-P removal rate was 86% at the C/P ratio of 7.2-14.1. Also, the analysis of nitrogen and phosphorous removal characteristics were analyzed in relation to media charge. The comparison between with and without media charge in the water-mill showed that while the nitrogen removal efficiencies were 86-94% and 85-89% respectively, the difference of phosphorous removal efficiencies were between the two conditions was not significant, thus it suggested that the media charge has less effect on the removal efficiency of phosphorous compared to that of nitrogen.

• Journal of Menopausal Medicine
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• v.24 no.3
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• pp.163-168
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• 2018

Objectives: To investigate the rate of postoperative urinary retention (POUR) and identify the risk factors for this complication in women who underwent transvaginal uterosacral suspension surgery. Methods: A retrospective chart review was conducted for 75 women who underwent transvaginal uterosacral suspension surgery with vaginal hysterectomy, repair of cystocele, and levator myorrhaphy with/without transobturator anti-incontinence surgery. POUR was defined as a need for continuous intermittent catheterization on the third day subsequent to removal of the urethral indwelling catheter. Results: Acute POUR was reported in 18 women (24.0%). Thirty-six of the 75 patients (48.0%) had undergone anti-incontinence surgery. Crude analysis revealed significant association between the following variables and the risk of POUR: hypertension, the lower average flow rate in the pressure-flow study (PFS), greater post-void residual (PVR) urine volume in PFS, and PVR >30% of the total bladder capacity (TBC) in PFS. In the logistic regression analysis, PVR >30% of the TBC in PFS was identified as the only significant predictor of POUR (odds ratio, 15.4; 95% confidence interval, 2.5-90.9; P = 0.003). Conclusions: The PVR >30% of the TBC in PFS was identified as the only predictive factor of acute POUR in women who underwent transvaginal uterosacral suspension surgery.

• Korean Journal of Social Welfare Studies
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• v.45 no.2
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• pp.123-146
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• 2014

This study aims to investigate the employment duration and the probability of quitting the job at first return-to-work of injured workers. This study collected data with structured questionnaires and finally included 515 injured workers. The Kaplan-Meier method is used for describing the employment duration, and the Cox regression is used to identify significant factors on the probability of quitting the job at first return-to-work. The results show that among the all respondents, the 5.65% quitted the job within 1 month, 14.14% within 3 months, 23.7% within 6 months, and 32.81% within 1 years. The Cox regression results show that the probability of quitting the job at first return-to-work is significantly affected by age, marital status, education, employment period when happened the accident, job retention, income change, and classification of diseases. As a result, some implication and policies are suggested for the return-to-work and employment durability of injured workers.