온수배관을 이용한 온실의 난방성능

윤용철(Yong Cheol Yoon),신익수(Yik Soo Shin),김현태(Hyeon Tae Kim),배승범(Seoung Beom Bae),최진식(Jin Sik Choi),서원명(Won Myung Suh) (사)한국생물환경조절학회 2012 생물환경조절학회지 Vol.21 No.2

본 연구는 온실의 난방 에너지 절감을 목적으로 온실 내부에 알루미늄 온수배관을 설치하여 난방효과에 대한 기초자료를 구축하고자 수행되었다. 그 연구결과를 요약하면 다음과 같다. 전체 실험을 포함하여 온실내의 높이별 온도편차는 4.0~7.0℃ 정도의 범위로서 그 차이가 크게 나타났다. 팬코일유니트(FCU)를 작동시킨 경우가 작동시키지 않은 경우에 비해 유출입수의 온도차가 3.3℃ 정도 크고, 소비전력량은 36.2~40.1% 정도 증가하였으며, 시간당 방열량은 44.6~52.0% 정도 증가하는 것으로 나타났다. 실험기간동안 순환유량은 0.48~0.49L · s<SUP>?1</SUP> 정도의 범위에 있었고, 평균유속은 1.53~1.56m · s<SUP>?1</SUP> 정도였다. 유출입수의 평균 온도차는 6.24~11.50℃이었다. 최저 외기온 ?14.0~?0.6℃ 범위에서 설정온도별 방열량은 135,930~307,150㎉ 정도의 범위로서 시간당 9,610~19,630㎉ · h<SUP>?1</SUP> 정도의 범위에 있었다. 이것은 최대난방부하의 약 23~53% 정도의 난방에너지를 공급할 수 있을 것으로 나타났다. 전체 방열량과 소비전력량은 각각 2,548,306㎉ 및 3,075.7㎾h이다. 화석연료인 경유로 난방할 경우, 소요되는 경유의 총 소비량은 281.6L 정도이고 비용은 321,000won인 것으로 나타났다. 농가용 전력요금을 적용하면 전력사용에 대한 총비용은 110,730won 정도로서 경유 소비 비용의 33.5% 정도로 나타났다. 실험구의 온도가 대조구보다 약 8.3~14.6℃ 정도 높게 나타났다. This research was conducted to obtain basic data with regard to the heating performance that would be produced by installing an aluminum hot water pipe inside the greenhouse with the goal of reducing the heating energy in greenhouse. The research results are summarized as follows. The degree of difference in relation to the temperature by height within the greenhouse during the entire experiment was significant - within the range of 4.0~7.0℃. The temperature difference between incoming and outgoing water was about 3.3℃ greater when FCU was activated compared to when it was not activated. Meanwhile, the amount of energy consumed increased about 36.2~40.1%. The amount of pyrexia per hour also increased by 44.6~52.0%. During the experiment period, circulated flux was within the range of 0.48~0.49 L · s<SUP>?1</SUP> while average fluid speed was 1.53~1.56 m · s<SUP>?1</SUP>. The average temperature difference between incoming and outgoing water was 6.24~11.50℃. The amount of heating value by each set temperature within the minimum outdoor temperature range of ?14.0~?0.6℃ was 135,930~307,150 ㎉, and the range was within the 9,610~19,630 ㎉ · h<SUP>?1</SUP> per hour. This demonstrated that about 23~53% heating energy of the maximum heating load could be supplied. Total radiating value and amount of energy consumed were 2,548,306 ㎉ and 3,075.7 ㎾h, respectively. When heating takes place using oil, which is a fossil fuel, the total amount of light oil consumed was 281.6 L while the cost was 321,000 won. When the electricity cost for farms is applied, the total cost was about 110,730 won, which is about 33.5% of the cost required compared to oil consumption. The temperature at in the experiment area was about 8.3~14.6℃ higher compared to that of the control area.

Ignition Characteristics of Residential Series Arc Faults in 220-V HIV Wires

Won-Sik Moon,Jae-Chul Kim,Ara Jo,Sun-Bae Bang,Won-Sik Koh IEEE 2015 IEEE transactions on industry applications Vol.51 No.3

<P>Unintentional arc faults due to damaged power line cords and loose connections can cause serious fires; thus, they are a safety hazard in residential areas. Therefore, arc fault circuit interrupters are being increasingly used in homes to protect against arcs that may cause fires. In this paper, we analyzed the ignition characteristics of series arcs on the basis of load current. Furthermore, we recommended suitable arc clearing times through characteristics analysis in the Korean residential electric environment. We determined the arc clearing time via the carbonized path arc clearing time test using an ultraviolet signal detecting system according to the test method of the UL 1699 standard. In the experiments, heat-resistant indoor PVC insulated (HIV) wires, which is a type of residential electrical wire, were used as the wire specimens.</P>

Effects of multi-walled carbon nanotubes on rheological and physical properties ofpolyamide-based thermoplastic elastomers

Won-Sik Bae,Oh Joo Kwon,김병철,채동욱 한국유변학회 2012 Korea-Australia rheology journal Vol.24 No.3

The polyamide-based thermoplastic elastomers (Pebax) were melt compounded with multi-walled carbon nanotubes (MWNTs: 0.25~5wt%) and the variation of rheological and physical properties with MWNT contents was investigated. The crystallization temperature (Tc) of the nanocomposites with 0.5wt% MWNTs was most increased by ca. 8oC, but it was decreased by further addition. In addition, the presence of MWNTs broadened the Tc peak with increasing nanotube contents. In contrast, the melting behavior was little influenced by the presence of MWNTs for all compositions. The incorporation of MWNTs increased the complex viscosity with MWNT contents and the abrupt increase was observed from 1wt%. In addition, lower Newtonian flow region became disappearing with increasing MWNT contents, exhibiting notable shear thinning behavior from 1wt% loading. Storage modulus was increased with MWNT contents in a similar manner to viscosity. Casson plot demonstrated a non-zero positive intercept for all the samples. In particular, the abrupt increase of yield stress was observed from 1wt% loading. In the Cole-Cole plot, the nanocomposites gave a deviated curve from pure Pebax and the slope was decreased with increasing MWNT contents. The relaxation time calculated from viscoelastic parameters was increased with nanotube contents, but the increasing extents were reduced with increasing frequency. From 2wt% MWNTs, the elec\-trical conductivity was observed, indicating that the electrical percolation existed between 1.5 and 2wt%. At 0.25wt% loading the tensile strength was slightly increased, but it was gradually decreased by further addition. The introduction of MWNTs increased the tensile modulus with nanotube contents. In addition, ductile properties were reduced with increasing MWNT contents, resulting in low toughness.

Ceramic-on-Ceramic Total Hip Arthroplasty: Minimum of Six-Year Follow-up Study

Won Sik Choy,김갑중,이상기,Kyoung Wan Bae,Yoon-Sub Hwang,Chang Kyu Park 대한정형외과학회 2013 Clinics in Orthopedic Surgery Vol.5 No.3

Background: This study examines the clinical and radiologic results of ceramic-on-ceramic total hip arthroplasties with regard towear, osteolysis, and fracture of the ceramic after a minimum follow-up of six years. Methods: We evaluated the results of a consecutive series of 148 primary ceramic-on-ceramic total hip arthroplasties that hadbeen performed between May 2001 and October 2005 in 142 patients. The mean age was 57.2 years (range, 23 to 81 years). Themean follow-up period was 7.8 years (range, 6.1 to 10.1 years). Preoperative diagnosis was avascular necrosis in 77 hips (52%),degenerative arthritis in 36 hips (24.3%), femur neck fracture in 18 hips (12.2%), rheumatoid arthritis in 15 hips (10.1%), and septichip sequelae in 2 hips (1.4%). Clinical results were evaluated with the Harris hip score, and the presence of postoperative groinor thigh pain. Radiologic analysis was done with special attention in terms of wear, periprosthetic osteolysis, and ceramic failures. Results: The mean Harris hip score improved from 58.3 (range, 10 to 73) to 92.5 (range, 79 to 100) on the latest follow-up evaluation. At final follow-up, groin pain was found in 4 hips (2.7%), and thigh pain was found in 6 hips (4.1%). Radiologically, all femoralstems demonstrated stable fixations without loosening. Radiolucent lines were observed around the stem in 25 hips (16.9%), andaround the cup in 4 hips (2.7%). Endosteal new bone formation was observed around the stem in 95 hips (64.2%) and around thecup in 88 hips (59.5%). No osteolysis was observed around the stem and cup. There were 2 hips (1.4%) of inclination changes ofacetabular cup, 2 hips (1.4%) of hip dislocation, 1 hip (0.7%) of ceramic head fracture, and 1 hip (0.7%) of squeaking. The Kaplan-Meier survival rate of the prostheses was 98.1% at postoperative 7.8 years. Conclusions: The ceramic-on-ceramic total hip arthroplasty produced excellent clinical results and implant survival rates with nodetectable osteolysis on a minimum six-year follow-up study. The ceramic-on-ceramic couplings could be a reasonable option ofprimary total hip arthroplasty for variable indications.

Serum NT-proBNP Level as a marker for cardiopulmonary function in preeclampsia(초)

( Won Joon Seong ),배지혜 ( Ji Hye Bae ),( Gun Oh Chong ),( Dae Gy Hong ),( Taek Hoo Lee ),( Yoon Soon Lee ),( Young Lae Cho ),( Sang Sik Chun ),( Il Soo Park ) 대한산부인과학회 2009 대한산부인과학회 학술대회 Vol.95 No.-

Longitudinal comparison of anxiety and depression between idiopathic pulmonary fibrosis (IPF) and non-IPF interstitial lung disease : a prospective cohort study

( Won Bae ),( Jaeyoung Cho ),( Jinwoo Lee ),( Young Sik Park ),( Chang-hoon Lee ),( Sang-min Lee ),( Jae-joon Yim ),( Chul-gyu Yoo ),( Young Whan Kim ),( Sung Koo Han ),( Sun Mi Choi ) 대한결핵 및 호흡기학회 2018 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.126 No.-

Background: There were few studies that investigated the differences in incidence of anxiety and depression according to individual diseases constituting ILD. We evaluated the differences in the incidence of anxiety and depression between idiopathic pulmonary fibrosis (IPF) and non-IPF ILD, and the changes to it at one year follow-up. Methods: Patients included those in the prospective ILD cohort of Seoul National University Hospital between March 2013 and August 2018. The Hospital Anxiety and Depression Scale (HADS) questionnaire was used to assess patients’ anxiety and depression. Results: There were 224 patients with ILD. The patients with IPF numbered 154 (68.8%), while those with non-IPF ILD numbered 70 (31.2%). Totally, 111 patients completed a follow-up HADS questionnaire one year later (77 in the IPF group, 34 in the non-IPF group). In the IPF group, 20.8% (32/154) and 27.3% (21/77) (p=0.347) of patients suffered from anxiety and 29.9% (46/154) and 31.2% (24/77) (p=0.957) suffered from depression at baseline and one year follow-up, respectively. In the non-IPF group, 14.3% (10/70) and 23.5% (8/34) (p=0.372) of patients suffered from anxiety and 24.3% (17/70) and 17.6% (6/34) (p=0.608) suffered from depression at baseline and one year follow-up, respectively. Conclusion: The proportion of patients with anxiety and depression at baseline and one year follow-up was not significantly different between the two groups. At one year follow-up, the proportion of those with anxiety and depression increased among the IPF patients but it was not statistically significant.

Electrochemical Metallic Ion Migration Property of Multi-Layer Ceramic Capacitor for Car Electronics

Won Sik Hong,Mi-Song Kim,Joo Young Bae,So-Hee Hyun,배희훈,경준석,박은정,김종을,오주석 대한용접접합학회 2023 대한용접·접합학회지 Vol.41 No.6

As the use of electrical components in automobiles increases, the occurrence of electorchemical metallic ion migration (ECM), which is one of the causes of various failures in electrical components, is also increasing. Therefore, in this study, 1608 MLCC chip components were used for temperature-humidity-bias (THB) tests at 65℃/85%R.H., 65℃/95%R.H., and 85℃/85%R.H. Three types of THB tests were conducted for 2,934 h. For the THB test, voltages of 3.3, 12 and 24 V were applied, and real-time resistance of MLCCs were measured at every 40 mms intervals. During the ECM test, the ECM occurrence time was measured by monitoring the insulation resistance of between the electrode of MLCC under each THB test conditions. The failure criteria for ECM occurrence were 106 Ω or less, and the time when it occurred more than twice was judged as the ECM failure criteria. Based on the ECM occurrence time, the mean life time of ECM occurrence according to temperature, humidity and applied voltage conditions was derived through Weibull statistical analysis. Finally, we compared and analyzed the sensitivity of MLCC components to ECM generation under use environment of automotive electronics.

Effects of multi-walled carbon nanotubes on rheological and physical properties of polyamide-based thermoplastic elastomers

Bae, Won-Sik,Kwon, Oh-Joo,Kim, Byoung-Chul,Chae, Dong-Wook 한국유변학회 2012 Korea-Australia rheology journal Vol.24 No.3

The polyamide-based thermoplastic elastomers (Pebax$^{(R)}$) were melt compounded with multi-walled carbon nanotubes (MWNTs: 0.25~5 wt%) and the variation of rheological and physical properties with MWNT contents was investigated. The crystallization temperature ($T_c$) of the nanocomposites with 0.5 wt% MWNTs was most increased by ca. $8^{\circ}C$, but it was decreased by further addition. In addition, the presence of MWNTs broadened the $T_c$ peak with increasing nanotube contents. In contrast, the melting behavior was little influenced by the presence of MWNTs for all compositions. The incorporation of MWNTs increased the complex viscosity with MWNT contents and the abrupt increase was observed from 1 wt%. In addition, lower Newtonian flow region became disappearing with increasing MWNT contents, exhibiting notable shear thinning behavior from 1 wt% loading. Storage modulus was increased with MWNT contents in a similar manner to viscosity. Casson plot demonstrated a non-zero positive intercept for all the samples. In particular, the abrupt increase of yield stress was observed from 1 wt% loading. In the Cole-Cole plot, the nanocomposites gave a deviated curve from pure Pebax and the slope was decreased with increasing MWNT contents. The relaxation time calculated from viscoelastic parameters was increased with nanotube contents, but the increasing extents were reduced with increasing frequency. From 2 wt% MWNTs, the electrical conductivity was observed, indicating that the electrical percolation existed between 1.5 and 2 wt%. At 0.25 wt% loading the tensile strength was slightly increased, but it was gradually decreased by further addition. The introduction of MWNTs increased the tensile modulus with nanotube contents. In addition, ductile properties were reduced with increasing MWNT contents, resulting in low toughness.

RECENT RESEARCH PROGRESS OF H2 PRODUCTION TECHNOLOGY

Won Chul Cho,Kyoung Soo Kang,Ki Kwang Bae,Change Hee Kim,Seong Uk Jeong,Chu Sik Park 한국신재생에너지학회 2014 AFORE Vol.2014 No.-

REACTIVITY OF IRON OXIDE WITH CO+H₂+CO₂ GAS MIXURE FOR CHEMICAL LOOPING PROCESS FOR H2 PRODUCTION

Won Chul CHO,Kyoung Soo KANG,Ki Kwang BAE,Change Hee KIM,Seong Uk JEONG,Chu Sik PARK,Sang Done Kim 한국신재생에너지학회 2012 AFORE Vol.2012 No.-