• 한국방재안전학회논문집
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• 제17권1호
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• pp.27-35
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• 2024

본 논문은 순환골재 표면에 부착된 시멘트 페이스트 및 모르타르를 제거하는 데 있어 화학적 중화반응 및 초음파 세척의 적용 가능성을 평가하기 위한 실험적 연구 결과를 제시한다. 최적의 초음파 세척 효율 및 화학적 중화반응을 도출하기 위하여 초음파 진동수, 화학용액의 종류 등을 변수로 한 실험이 수행되었다. 그 결과 최적 진동수는 24 kHz로 나타났으며, 염산 15% 용액에 침지시킨 후 30분 가진하는 것이 최적 조건이라는 결론이 도출되었다. 또한, 품질 개선된 순환 굵은 골재의 비중, 흡수율, 마모율은 일반골재와 유사하며 KS F 2527 기준을 모두 만족하는 것으로 나타났다. 따라서, 본 연구를 통해 제안된 방법을 통해 품질 개선된 순환골재는 콘크리트용으로 사용이 가능할 것으로 판단된다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권7호
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• pp.1041-1047
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• 2005

This study was carried out to investigate the changes of chemical and sensory properties and cholesterol lowering effect of milk treated with $\beta$-cyclodextrin to reduce cholesterol and supplemented with evening primrose oil (EPO). The average cholesterol removal rate was 93.5%. The thiobarbituric acid (TBA) absorbance increased proportionally to storage period and amount of EPO addition. TBA absorbance was significantly different in the EPO-added groups from that in unadded groups in all periods. The production of short-chain free fatty acids (FFA) increased with longer period of storage. From 6 days of storage, the amounts of short-chain FFA in 6 and 10% EPO-added groups were significantly different from other groups. The scores for all sensory characteristics indicated that sensory quality decreased with both storage time and increasing amount of EPO. Oxidative off-flavor and off-taste were more intense with higher amounts of EPO addition and longer storage period. Also, the higher the amount of EPO addition, the lower overall scores throughout the 15 day storage. Feeding 10% EPO-supplemented cholesterol-reduced milk increased high density lipoprotein (HDL) in male Sprague-Dawley rats by 76%, which is significantly different from the control (27%).

• 대한환경공학회지
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• 제31권8호
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• pp.655-662
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• 2009

원통형 여과장치의 실규모 설계 및 운전에 필요한 기초자료를 얻기 위하여 산출유량을 단계적으로 증가시키는 파일럿 실험을 수행하면서 수질지표들과 폐색도 진행을 조사하였다. 유량을 0.8 L/min에서 2.4 L/min로 증가시키는 경우 BOD, SS, 그리고 탁도의 제거율은 각각 약 80%, 95% 이상, 그리고 90% 이상으로 거의 일정하게 유지되었으나 COD 제거율은 44%에서 29%로 감소하였다. 산출유량이 증가할수록 오염물 단위농도를 제거하는데 소요되는 체류시간은 감소하였으며, 1 mg-COD/L를 제거하는데 필요한 체류시간은 산출유량 0.8 L/min인 경우 83분이었고 2.4 L/min에서는 45분이어서 양수율이 낮은 것보다는 높은 것이 호소의 오염제거에 더 유리함을 알 수 있었다. 여과장치의 폐색은 표층에서 집수관쪽으로 진행하며, 산출유량이 증가하면 폐색도도 증가하지만 2년 이상의 운전에도 폐색이 문제되지는 않아 본 장치가 호소의 수질개선에 효과적으로 사용될 수 있을 것으로 기대되었다.

• 한국정보처리학회논문지
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• 제6권2호
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• pp.534-542
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• 1999

고정 비트 율 채널을 통해 비디오를 전송할 때 잘 설계된 율 제어 방식은 전반적인 화질을 향상시킬 수 있으며, 율 제어 방식은 MPEG 비디오 표준에는 포함되어 있지 않기 때문에 어떤 율 제어 방식을 채택했는가에 따라 MPEG 비디오 코덱의 성능은 많은 차이를 나타낼 수 있다. MPEG에서 제안된 기존의율 제어 방식은 장면전환이 없을 때는 좋은 성능을 보이나, 장면 전환된 영상은 잘 처리하지 못하는 단점을 갖고 있다. 따라서 장면전환 후에는 화질이 열화 되고 버퍼 넘침이 발생할 가능성이 높아진다. 본 논문에서는 국소분산을 이용한 새로운 장면전환 검출 방식을 제안한다. 또한, 장명전환 검출부에서 계산된 국소분산을 율 제어부의 비트 할당 및 적응적 양자화 단계에서 재사용하여 영상의 국소적인 특성을 고려한 양자화 변수, mqunt,를 결정하는 방식과 장면전환이 발생했을 경우 장면전환 발생 이전의 몇 프레임에서 절약한 비트 수를 장면 전환된 영상에 부가적으로 할당함으로써 장면전환을 효과적으로 대처하는 적응적 율 제어 방식을 제안한다. 제안된 방식을 검증하기 위해 컴퓨터 모의실험을 수행하였다. 제안된 검출방식은 장면전환을 정확하게 검출하였고, 제안된 율 제어 방식은 기존의 MPEG 방식보다 우수한 율 제어 성능을 보였다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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• pp.215-225
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• 2006

Today's requirements for print-press runnability and print quality demand an optimised absorption and adhesion of printing ink on the paper surface. Modern coating concepts for high glossing offset grades use ultra fine pigments, whereas binder level has continuously been decreased to a minimum in recent years to achieve the highest possible sheet gloss development and for economical reasons. Both the ultra fine pigments and the reduced binder levels lead in many cases to a faster ink setting rate. On the other hand, matt paper grades use relatively coarse pigments leading to a slow ink setting compared to the high glossing papers. Both too fast and too slow ink setting properties implicate drawbacks in print quality and print press runnability. The mechanisms behind the interactions between ink and coating have been presented in many previous publications. The purpose of this study was to determine and quantify how the ink setting rate is influenced by pigment system (GCC and GCC/clay blends), latex level and latex properties in the topcoat of double coated sheet fed offset paper. The roles of binder level and type in the precoat were also assessed. The effect of calendering (temperature and pressure) was studied with one formulation. The resulting ink setting characteristics were tested using three different laboratory testing instruments. The correlation amongst the different laboratory testing methods is discussed. The results show that by varying the latex properties, the pigment system and/or latex addition level, the ink tack development of ink applied to a topcoat pigment system can be significantly influenced. It can be slowed down as often desired with ultra fine pigments or speeded up in the case of coarse pigments. There was no visible effect on the ink setting rate by using different binder systems in the precoat..

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.815-826
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• 2009

The paper presents a case study addressing the design and construction aspects for DCM(Deep Cement Mixing) method employed as the foundation of a caisson type breakwater with heavy weight(10,700 ton/EA) and a high design wave height($H_{1/3}$=8.7m). The DCM was designed for the project(Ulsan New Port North Breakwater Phase 1) by optimizing the pattern of DCM columns with a combination of short and long columns (i.e., block type(upper 3m)+wall type(lower)) and considering overlapped section between columns as a critical section against shear force where the coefficient of effective width of treated column($\alpha$) was estimated with caution. It was shown that the value can be 0.9 under the condition with the overlapped width of 30cm. In addition to that, a field trial test was performed after improving conventional DCM equipment (e.g., mixing blades, cement paste supplying pipes, multi auger motor, etc.) to establish a standardized DCM construction cycle (withdrawal rate of mixing blades) which can provide the prescribed strength. The result of the field strength test for cored DCM specimens shows that the averaged strength is larger than the target strength and the distribution of the strength(with a defect rate of 7%) also satisfies with the quality control normal distribution curve which allows defect rate of 15.9%.

• Reproductive and Developmental Biology
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• 제37권4호
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• pp.281-287
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• 2013

In mammal, unfertilized oocytes remain in the oviduct or under in vitro culture, which is called "oocyte aging". This asynchrony negatively affects fertilization in pre- and post-implantation embryo development. Caffeine a phosphodiesterase inhibitor is known to rescue oocyte aging in several species. The objective of this study is to determine the cytoskeleton distribution in aged oocytes and the embryo developmental ability of aged oocytes in the present or absence of caffeine during maturation. Caffeine treatment increased the incidence of normal spindle assembly of aged oocytes (treatment, $67.57{\pm}4.11%$ aging, $44.61{\pm}6.4%$) and no significant differences compared to control group. Fluorescence values were compared using ROS (Reactive oxidation species) stain. Fluorescence values appear of control group intensity rate ($51.53.{\pm}3.80$), aging group ($68.10{\pm}5.54$) and treatment of caffeine ($45.04{\pm}2.98$). Aged oocytes that were derived from addition of caffeine to the IVM (in vitro maturation) medium had significantly increased 2-cell that developed to the blastocyst stage compared to the aging group. Blastocysts, derived from caffeine treatment group, significantly increased the total cell number compare aging ($90.44{\pm}10.18$ VS $67.88{\pm}7.72$). Apoptotic fragments of genomic DNA were measured in individual embryo using TUNEL assay. Blastocyst derived from caffeine treatment group decreased significantly the apoptotic index compared to blastocyst derived from aging group. In conclusion, we inferred that the caffeine treatment during oocyte aging can improve the developmental rate and quality in bovine embryos developing in vitro.

• 한국물환경학회지
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• 제36권6호
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• pp.535-545
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• 2020

This study aims to conserve and monitor energy use in public sewage treatment plants by utilizing data from the SCADA system and by controlling the aeration rate required for maintaining effluent water quality. Power consumption in the sewage treatment process was predicted using the equipment's uptime, efficiency, and inherent power consumption. The predicted energy consumption was calibrated by measured data. Additionally, energy efficiency indicators were proposed based on statistical data for energy use, capacity, and effluent quality. In one case study, a sewage treatment plant operated via the SBR process used ~30% of energy consumed in maintaining the bioreactors and treated water tanks (included decanting pump and cleaning systems). Energy consumption analysis with the K-ECO Tool-kit was conducted for unit processing. The results showed that about 58.7% of total energy consumed was used in the preliminary and biological treatment rotating equipment such as the blower and pump. In addition, the energy consumption rate was higher to the order of 19.2% in the phosphorus removal process, 16.0% during sludge treatment, and 6.1% during disinfection and discharge. In terms of equipment energy usage, feeding and decanting pumps accounted for 40% of total energy consumed following 27% for blowers. By controlling the aeration rate based on the proposed feedback control system, the DO concentration was reduced by 56% compared pre-controls and the aeration amount decreased by 28%. The overall power consumption of the plant was reduced by 6% via aeration control.

• 한국물환경학회지
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• 제21권1호
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• pp.52-58
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• 2005

The assessment on characteristics of hydraulic behavior and water quality variations of underground reservoirs of buildings were studied. Firstly, it was thought that underground reservoir capacities($m^3$) of buildings should be not determinated by the uniform and same methods but be estimated on the basis of the dwelling areas on dominated households and their residential characteristics, because these characteristics influence significantly on actual water usages and patterns of buildings. Secondly, it was likely that the average reduction rate of residual chlorine in underground reservoirs were affected from the their capacities, because the average reduction rate of residual chlorine in underground reservoirs under $1,000m^3$ was 43 percent, on the other hand, that rate of underground reservoirs over $1,000m^3$ was 60 percent. Thirdly, through the field investigation, the retention time of drinking water in underground reservoirs were in the range from 0.3 day to 3.9 day. In addition to, the average reduction rate of residual chlorine were depended largely on the retention time of drinking water. When the retention time was under 24 hours, the average reduction rate of residual chlorine was 45 percent, and in case of over 24 hours, was 49 percent. Fourth, water level in underground reservoirs was averagely varied in the range from 0.1 m to 2.65 m at the height of underground reservoirs. If considered actual height of underground reservoirs, 37.6 percent of the height of underground reservoirs was only used. Consequently, the frequency of the inflow and outflow of drinking water in underground reservoir were very increased, and had an effect on the reduction of residual chlorine. Lastly, the investigations on hydraulic structure characteristics of underground reservoirs inside showed the locations of inflow and outflow of drinking water almost were in the opposite direction. And some buildings had several baffles in the middle. Nevertheless, their installations had no beneficial for the improvement of water quality.

• Asian-Australasian Journal of Animal Sciences
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• 제26권12호
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• pp.1753-1761
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• 2013

The individual and interactive effects of Schisandra chinensis powder (SCP) and sodium nitrite additions on color, pH, water holding capacity, residual nitrite, 2-thiobarbituric acid reactive substances (TBARS), volatile basic nitrogen, texture properties, fatty acids, amino acids and sensory evaluation of cooked pork sausages were investigated after 20 d of storage at $4^{\circ}C$. The powders (0, 0.5 and 1.0%) were added to sausages either alone or in combination with nitrite (0 and 100 ppm). SCP added-sausages showed lower $L^*$ (lightness) and W (whiteness) values, and higher $b^*$ (yellowness) values than sausage containing no nitrite, and exhibited the highest $a^*$ values at a 0.5% addition (p<0.05). Residual nitrite and TBARS values were found to be significantly reduced as the addition levels of SCP increased (p<0.05). As the addition of SCP increased, the sausage showed gradually decreased brittleness, cohesiveness, springiness, gumminess and chewiness, while adhesiveness increased. Polyunsaturated fatty acid, n-6 and n-6/n-3 fatty acid ratio concentrations were significantly higher in sausages containing SCP (p<0.05). The addition of SCP to sausage significantly (p<0.05) increased the ammonia content (by 0.5% SCP) and aromatic amino acid concentrations (by 1.0% SCP) (p<0.05). Inclusion of SCP in sausage meat resulted in a significant deterioration in quality characteristics of flavor, springiness, juiciness and overall acceptability (p<0.05). As expected, the observed changes in $a^*$, W, pH, shear force, texture property, TBARS, fatty acid, amino acid and sensory score of sausages, depended on the rate of addition of nitrite (p<0.05). These results suggest that SCP addition is not an effective way of improving the sensory evaluation of sausages, but may beneficially affect TBARS, nitrite scavenging activity, fatty acid and amino acid content in pork sausages.