• Title/Summary/Keyword: duration reduction

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Estimation of Areal Reduction Factors for the Youngsan River Basin (영산강유역의 면적우량감소계수 산정)

  • Lee, Jae-Hyung;Koh, Won-Joon;Lee, Yoon-Young;Kim, Dae-Geun
    • Journal of Korea Water Resources Association
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    • v.39 no.10 s.171
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    • pp.813-822
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    • 2006
  • By analyzing the concurrent rainfall data from rainfall gauges positioned in the Youngsan River basin, the areal reduction factors related to the rainfall characteristics of the Youngsan River basin are estimated. The estimated values are compared with the values of the Han River basin, and show that the rate of decrease of the areal reduction factors of the Youngsan River basin are smaller than those of the Han River basin as the basin area is increasing. That is especially true for short-term duration storm events. These findings reveal that the spatial variations in the Youngsan River basin's storms are smaller than the spatial variations of the storms In the Han River basin, due to the size of the two basin areas in addition to the topological characteristics that affect the rainfall distributions.

Analysis on the Effect of Infiltration Collector Well Installation on the Water Control (침투통의 설치에 따른 치수효과 분석)

  • Shim, Jae-hyun;Lee, Cheol-kyu;Lee, Jong-kook;Kim, Jin-young
    • Proceedings of the Korea Water Resources Association Conference
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    • 2004.05b
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    • pp.298-302
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    • 2004
  • In this study, the runoff reduction effect was analyzed quantitatively focusing on the infiltration collector well located in the test area. On the basis of the analysis of the data obtained by examining the real-time measurement field data, the runoff reduction was examined through the measured rainfall of the year 2003 by applying the analysis result, with the PCSWMM model to the Kiheung-Gugal residential area, which is selected as the test basin. According to the analysis, it is revealed that an infiltration collector well can reduce up to $65\~98\%$ of runoffs, compared to a conventional one. For measured rainfalls, an infiltration collector well was able to reduce up to $15\~23\%$ of runoffs and $3\~25\%$ of peak runoffs. These results show that the effects of infiltration collector wells might vary with rainfall intensity and its duration. However, the infiltration collector well was confirmed as the one of the alternatives of runoff reduction facilities in urbanized catchment.

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Strut Support with Tricortical Iliac Allografts in Unstable Proximal Humerus Fractures: Surgical Indication and New Definition of Poor Medial Column Support

  • Lee, Seung-Jin;Hyun, Yoon-Suk;Baek, Seung-Ha
    • Clinics in Shoulder and Elbow
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    • v.22 no.1
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    • pp.29-36
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    • 2019
  • Background: The execution of fibular allograft augmentation in unstable proximal humerus fractures (PHFs) was technically demanding. In this study, the authors evaluated the clinical and radiographic outcomes after tricortical iliac allograft (TIA) augmentation in PHFs. Methods: We retrospectively assessed 38 PHF patients treated with locking-plate fixation and TIA augmentation. Insertion of a TIA was indicated when an unstable PHF showed a large cavitary defect and poor medial column support after open reduction, regardless of the presence of medial cortical comminution in preoperative images. Radiographic imaging parameters (humeral head height, HHH; humeral neck-shaft angle, HNSA; head mediolateral offset, HMLO; and status of the union), Constant score, and range of motion were evaluated. Patients were grouped according to whether the medial column support after open reduction was poor or not (groups A and B, respectively); clinical outcomes were compared for all parameters. Results: All fractures healed radiologically (average duration to complete union, 5.8 months). At final evaluation, the average Constant score was 73 points and the mean active forward flexion was $148^{\circ}$. Based on the Paavolainen assessment method, 33 patients had good results and 5 patients showed fair results. The mean loss of reduction was 1.32 mm in HHH and 5.02% in HMLO. None of the parameters evaluated showed a statistically significant difference between the two groups (poor and not poor medial column support). Conclusions: In unstable PHFs, TIA augmentation can provide good clinical and radiological results when there are poor medial column support and a large cavitary defect after open reduction.

Porcine-derived soft block bone substitutes for the treatment of severe class II furcation-involved mandibular molars: a prospective controlled follow-up study

  • Jae-Hong Lee;Ji-Hoo Han;Seong-Nyum Jeong
    • Journal of Periodontal and Implant Science
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    • v.53 no.6
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    • pp.406-416
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    • 2023
  • Purpose: No evidence exists regarding the advantages of periodontal regeneration treatment for furcation defects using soft block bone substitutes. Therefore, this randomized controlled trial aimed to assess the clinical and radiographic outcomes of regenerative therapy using porcine-derived soft block bone substitutes (DPBM-C, test group) compared with porcine-derived particulate bone substitutes (DPBM, control group) for the treatment of severe class II furcation defects in the mandibular molar regions. Methods: Thirty-five enrolled patients (test group, n=17; control group, n=18) were available for a 12-month follow-up assessment. Clinical (probing pocket depth [PPD] and clinical attachment level [CAL]) and radiographic (vertical furcation defect; VFD) parameters were evaluated at baseline and 6 and 12 months after regenerative treatment. Early postoperative discomfort (severity and duration of pain and swelling) and wound healing outcomes (dehiscence, suppuration, abscess formation, and swelling) were also assessed 2 weeks after surgery. Results: For both treatment modalities, significant improvements in PPD, CAL, and VFD were found in the test group (PPD reduction of 4.1±3.0 mm, CAL gain of 4.4±2.9 mm, and VFD reduction of 4.1±2.5 mm) and control group (PPD reduction of 2.7±2.0 mm, CAL gain of 2.0±2.8 mm, and VFD reduction of 2.4±2.5 mm) 12 months after the regenerative treatment of furcation defects (P<0.05). However, no statistically significant differences were found in any of the measured clinical and radiographic parameters, and no significant differences were observed in any early postoperative discomfort and wound healing outcomes between the 2 groups. Conclusions: Similar to DPBM, DPBM-C showed favorable clinical and radiographic outcomes for periodontal regeneration of severe class II furcation defects in a 12-month follow-up period.

A Study on Characteristics of Drag Reduction Additive under High Temperature Range (고온영역에서 계면활성제의 마찰저감 성능 특성에 관한 연구)

  • Cho, Sung-Hwan;Ryu, Jae-Sung;Jung, Sang-Hoon
    • Journal of Energy Engineering
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    • v.19 no.2
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    • pp.116-120
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    • 2010
  • Overall total length of hydraulic pipe to transport the hot water in the domestic district heating network is above 3,000 Km approximately. This long pipe network requires a lots of the transport pumping power by surface friction of fluid. In this study, the drag reduction(DR) of Amin Oxide $C_{18}$ as non-ionic surfactant according to the fluid velocity, temperature and surfactant concentration under the condition of above $80^{\circ}C$ fluid temperature were investigated experimentally. Results showed that new amin oxide $C_{18}$ surfactant had DR of maximum 30% in fluid temperature of $80^{\circ}C$ and had 15% DR in fluid temperature over $100^{\circ}$ under short time test condition. And amine oxide had 155 hours duration time to keep the DR characteristic in the fluid temperature of $80^{\circ}$ and 1000 ppm concentration. But duration time of DR was decreased when fluid temperature increased.

A Study on the Anaerobic Treatment of the Phenol-bearing Wastewater with two Sludge Blanket-Packed Bed Reactors in Series (2단의 슬러지-고정상 반응기에서 페놀 함유 폐수의 혐시성 처리에 관한 연구)

  • 정종식;안재동;박동일;신승훈;장인용
    • Journal of Environmental Health Sciences
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    • v.21 no.4
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    • pp.1-9
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    • 1995
  • This study was carried to investigate the biodegradability of phenol in the wastewater with the two sludge blanket-packed bed reactor in series. Each reactor had a dimension of 0.09 m i.d. and 1.5 m height and consisted of two regions. The lower region was a sludge blanket of 0.5 m height and the upper region was a packed-bed of 1 m height. The packed bed region was charged with ceramic raschig rings of 10 mm i.d., 15 mm o.d. and 20 mm length. The reactors were operated at 35$\circ$C and the hydraulic retention time(HRT) was maintained 24 hours. The synthetic wastewater composed of glucose and phenol as major components was fed into the reactor in a continuous mode with incereasing phenol concentration. In addition, the nutrient trace metals($Na^+, Mg^{2+}, Ca^{2+}, PO_4^{3-}, NH_4^+, Co^{2+}, Fe^{2+}$ etc.) were added for growing anaerobes. The phenol concentration of the effluent, the overall gas production, the composition of product gas, the efficiency of COD reduction and the duration of acclimation period were measured to determine the performance of the anaerobic wastewater treatment system as the phenol concentration of the influent was increased from 600 to 2400 mg//l. Successfully stable biodegradation of phenol could be achieved with the anaerobic treatment system from 600 to 1, 800 mg/l of the influent phenol concentration. The upper level of influent phenol loading was high enough to meet most of the practical requirement. The duration of acclimation increased with the phenol loading. At steady state of the influent phenol concentration of 1800 mg/l, the treatment performance indicated the phenol reduction efficiency of 99%, the COD reduction efficiency of 99% and the gas production rate of 37 l/day. At the influent phenol concentration of 2400 mg/l, however, the operation of the treatment system was noted unstable. While the concentration of methane in biogas decreased with increasing the influent phenol loading, the carbon dioxide was increased. However, the concentration of hydrogen was varied negligibly. The concentration of methane was high enough to be used as a fuel. As a result, it is suggested that anaerobic phenol wastewater treament was economical in the sense of energy recovery and wastewater treatment.

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Efficacy of levetiracetam in refractory childhood epilepsy (난치성 소아 간질에서 levetiracetam의 효과)

  • Lee, Keon-Su;Kang, Joon-Won
    • Clinical and Experimental Pediatrics
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    • v.53 no.4
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    • pp.571-578
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    • 2010
  • Purpose : To evaluate the efficacy and safety of levetiracetam adjunctive therapy for reducing the rate of seizure frequency in children with intractable pediatric epilepsy. Methods : We reviewed the medical records of 86 patients with intractable pediatric epilepsy who visited our hospital between March 1989 and February 2009. Levetiracetam was included in the previous anticonvulsant regimen for at least 6 months and the reduction in the rate of seizure frequency was determined in follow-up examinations. We analyzed demographic data, seizure types, antiepileptic drug history, levetiracetam dose, adverse effects of levetiracetam therapy, treatment outcome, electroencephalogram findings, etc. Results : More than 50% reduction in the seizure frequency was observed in 62 of the 86 (72.1%) patients; 44 patients (51.1%) became seizure free, while the seizure frequency increased in 5.8% patients. The associations between seizure reduction rate and age, associated diseases, seizure types, and seizure frequency before treatment were not significant. However, the duration of disease, dose of levetiracetam, duration and frequency of anticonvulsant administration before levetiracetam therapy were significantly correlated. Electroencephalogram findings and the cause of epilepsy showed partial correlation. Forty (46%) patients showed adverse symptoms; the symptoms in the order of their frequency were somnolence, hyperactivity, irritability, aggressiveness, tiredness, etc. Conclusion : The findings of our study provide the evidence that levetiracetam adjunctive therapy is efficacious and well tolerated in various refractory childhood epilepsy cases.

Studies on the Duration of Immunity and Production of Antibody following Immunization with Inactivated Killed Japanese Encephalitis Vaccine (일본뇌염 백신 접종후 항 일본뇌염 항체의 생성율과 지속적인 면역반응에 대한 연구)

  • Cho, H.W.;Nam, J.H.;Lee, H.D.;Koh, H.C.;Kim, J.J.;Kim, E.J.;Lee, Y.S.;Lu, J.J.
    • Pediatric Infection and Vaccine
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    • v.4 no.1
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    • pp.116-125
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    • 1997
  • Purpose : Studies on the duration of immune response against Japanese encephalitis virus from recipients with JE vaccine (Nakayama-NIH strain) in Korea. Methods : To determinate the immune response and the duration of antibody against JE vaccine, 213 students were examined since 1994 using hemmaglutination inhibition test and plaque reduction neutralization test (PRNT). Results : 24 months after the first vaccination, haemmaglutination inhibition and neutralizing antibody maintained from the recipients 63.4% (>1:20) and 100% (>1:20), respectively. In April 1996, one dose booster to the same recipients those who were vaccinated in 1994, the GMT antibody for HI and PRNT titer were both increased from 1:11.6 to 1:13.2 and 1:275.7 to 1:348.1, respectively, after 6 months booster (after 30 months from the initial vaccination). This results showed that the antibody from the active immunity could be maintained more than 12 months after the initial vaccination. On the basis of these results, inactivated killed JE vaccine (Nakayama-NIH strain) using for preventing against JE purpose seems to produce antibody enough to protect against JE at present. Conclusions : Along with the results of this study demonstrating duration of antibody, the active immunization could be maintained as long as by initial vaccination of 2 doses, a single dose of booster vaccination made during a period of 1 month to 12 months and the successive booster vaccination by 2 or 3 year intervals. However, the immunization schedule should be concerned with both epidemiology of disease and the immune response of vaccinated individuals.

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Modified External Skeletal Fixation for Craniodorsal Coxofemoral Luxation in 5 Dogs (개의 전배측 고관절 탈구에서 변형된 외골격 고정 적용 5례)

  • Jung, Chang-Su;Lim, Ji-Hey;Byeon, Ye-Eun;Kim, Wan-Hee;Yoon, Jung-Hee;Kweon, Oh-Kyeong
    • Journal of Veterinary Clinics
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    • v.24 no.4
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    • pp.631-635
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    • 2007
  • Luxation of the hip is the most common luxation seen in small animals. Luxations are classified by the direction in which the femoral head lies in relation to the acetabulum and craniodorsal luxations are the most common type. Recommendations for treatment are based on the presence of preexisting disease, the type and duration of luxation and severity of concurrent injuries. In this study modified external skeletal fixation was used for craniodorsal coxofemoral luxation in 5 dogs. Luxated head Joint was reduced and fixator pins were applied into the greater trochanter, the middle point of iliac body and the lateral surface of sacroiliac joint in a closed fashion. Reduction was successful in 4 of the 5 operated limbs. Complications noted in this study included pin tract drainage, pin loosening and secondary fracture at the pin insertion site.

Evaluation of Early Compressive Strength of Concrete Using Early Strength Improvement Type Cement and Early Strength Activator (조기강도 개선형 시멘트 및 초기수화 촉진 혼화제를 사용한 콘크리트의 조기압축강도 발현특성 평가)

  • Park, Gyu-Yeon;Kim, Gyu-Yong;Choe, Gyoeng-Choel
    • Journal of the Korea Institute of Building Construction
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    • v.14 no.4
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    • pp.322-328
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    • 2014
  • In this study, revelation performance of concrete at early age according to types of cement, water reducing ratio of high performance superplasticizer and mixing of accelerator for early hydration was examined aiming for reduction of construction period of framework through securing strength at early age of concrete. It was observed that strength at early age, 5MPa in 12hours, 14MPa in 18hours, is secured by early strength improvement type cement and using promotion admixture for early hydration which are Sodium persulfate, Potassium hydroxide. Therefore cost reduction is expected to be possible in construction site by reducing construction period of frame work.