This experiment was carried out to study the effect of elapsed time after air flow cutoff on the germination rate of Italian ryegrass seed with different moisture contents during natural drying on reclaimed land, Jangheung and Kimje of Korea from 2023 to 2024, respectively. Seeds with moisture contents of 15.3, 22.3 and 28.0% were placed in vinyl bag (30 × 40 cm) at storage thicknesses of 10, 15, and 20 cm, and air flow was cutoff for 48 h. Seed moisture content, seed temperature (℃) and germination rate were investigated at 12-h intervals. After 48 h of airflow cutoff during natural drying, seed moisture content did not significantly differ among storage thickness treatment (p>0.05). When Italian ryegrass seeds with moisture contents of 27~28% were stored under conditions with air flow cutoff at 15~20cm thickness for 48 h, the seed temperature reached up to 30℃ and the germination rate was excellent at around 70~80%.

PURPOSES : This study is to initiated to estimate the impact of mixed traffic flow on expressway section according to the market penetration rate(MPR) of automated vehicles(AVs) using a enhanced intelligent driver model(EIDM). METHODS : To this end, microscopic traffic simulation and EIDM were used to implement mixed traffic flow on basic expressway section and simulation network was calibrated to understand the change of impact in mixed traffic flow due to the MPR of AVs. Additionally, MOEs of mobility aspects such as average speed and travel time were extracted and analyzed. RESULTS : The result of the impact of mobility MOEs by MPR and level of service indicated that 100% MPR of AVs normally affect positive impact on expressway at all level of service. However, it was analyzed that improvements in the level of service from LOS A to C are minimal until the MPR of AVs reaches 75% or higher. CONCLUSIONS : This research shows that impact of MPR of AVs using EIDM of mixed traffic flow on basic expressway. Increasing MPR of AVs affects positive impact on expressway at all level of services. However, MPR from 25% to 75% of AVs in LOS A to C shows minimal impacts. Therefore, to maximize the effectiveness of AVs, appropriate traffic operation and management strategies are necessary.

The effect of the change in air inflow velocity has been investigated at the opening of the malodor emission source to determine its influence on the Complex odor concentration. Both the Complex odor collection efficiency and concentrations were measured according to the change in airflow velocity. When the air inflow velocity was 0.1 m/s, it was observed that some of the generated gas streams were diffused to the outside due to low collection efficiency. In contrast, only the increased gas collection volume up to 0.5 m/s showed no substantial reduction of the Complex odor concentration, which indicates an increase in the size of the local exhaust system as well as the operation cost for the Complex odor control device. When the air inflow velocity reached 0.3 m/s, the Complex odor concentrations not only were the lowest, but the odorous gas could also be collected efficiently. The air inflow velocity at the opening of the malodor emission source was considered the key factor in determining the gas collection volume. Therefore, based on the results of this study, an optimal air inflow velocity might be suggestive to be 0.3 m/s.

The change in pressure measurement according to the low pressure tap blockage rate of the Venturi flowmeter used in domestic nuclear power plants was approached numerically. Blockage rates were modeled dividing by 1/10dT to the downstream side of the low pressure tab to identify differential pressure changes. As a result, differential pressure increased in proportion to the blockage rate, and there was no change in differential pressure measurement at 10 to 40 percent with relatively small blockage rate, but the error rate of 50% to 0.3% or higher was shown.

Two climate change scenarios, the RCP (Representative Concentration Pathways) 4.5 and the RCP 8.5 in the fifth Assessment Report (AR5) by Intergovernmental Panel on Climate Change (IPCC), were applied in the Yocheon basin area using the SWAT (Soil and Water Assessment Tool) model to estimate changes in flow rates and pollutant loadings in the future. Field stream flow rate data in Songdong station and water quality data in Yocheon-1 station between 2013~2015 were used for model calibration. While R2 value of flow rate calibration was 0.85 and R2 value of water qualities were in the 0.12~0.43 range. The total study period was divided into 4 sub periods as 2030s (2016~2040), 2050s (2041~2070) and 2080s (2071~2100). The predicted results of flow rates and water quality concentrations were compared with results in calibrated periods, 2015s (2013~2015). In both RCP scenarios, flow rate and TSS (Total Suspended Solid) loadings were estimated to be in increasing trend while TN (Total Nitrogen) and TP (Total Phosphorus) loadings showed decreasing patterns. Also, flow rates and pollutant loadings showed larger differences between the maximum and the minimum values in RCP 4.5 than RCP 8.5 scenarios indicating more severe effect of drought and flood, respectively. Dependent on simulation period and rainfall periods in a year, flow rate, TSS, TN and TP showed different trends in each scenario. This emphasizes importance of considerations on time and space when analyzing climate change impacts of each variable under various scenarios.

Recently, application areas based on M2M (Machine-to-Machine communications) and IoT (Internet of Things) technologies are expanding rapidly. Accordingly, water flow and water quality management improvements are being pursued by applying this technology to water and sewage facilities. Especially, water management will collect and store accurate data based on various ICT technologies, and then will expand its service range to remote meter-reading service using smart metering system. For this, the error in flow rate data transmitting should be minimized to obtain credibility on related additional service system such as real time water flow rate analysis and billing. In this study, we have identified the structural problems in transmitting process and protocol to minimize errors in flow rate data transmission and its handling process which is essential to water supply pipeline management. The result confirmed that data acquisition via communication system is better than via analogue current values and pulse, and for communication method case, applying the industrial standard protocol is better for minimizing errors during data acquisition versus applying user assigned method.

본 연구는 단면변화를 고려한 수위-단면적 변화 및 평 균 유속-단면적 간의 상관관계를 분석하여 유량 산정 및 하천관리에 활용하고자 하였다. 수위에 따른 단면적 변화 는 SB-A 지점은 1.0 m, 1.9 m, SB-C 지점은 0.6 m, 1.8 m, CL-A 지점은 1.0 m, 1.8 m, OS-A 지점은 0.6 m, 2.0m에서 발생되었다. 이 중 첫 번째 변화는 평∙저수기에 해당되 고, 두 번째 변화는 홍수기 및 하천 좌∙우 안에 인위적 ∙자연적으로 형성된 둔치 등으로 판단된다. 수위-단면적 변화에 따른 관계식의 기울기는 지수형 0.5539~1.9013, 선형 9.040~52.544의 범위를 가진다. 기울기는 두 곡선 모두 고수위로 갈수록 증가하는 경향을 보인다. 평균유 속-단면적 변화의 관계는 지수와 직선의 방정식으로 지 수형 기울기와 상관계수는 각각 0.1182~0.8734, 0.22~ 0.86이며, 선형의 기울기와 상관계수는 0.0028~0.1032, 0.20~0.87로 분석되었다. SB-A, SB-C 지점의 저수위는 다른 수위보다 상관관계가 높게 산정되었는데, 이는 수위 구간이 좁고, 하천 단면적의 변화가 크지 않기 때문으로 판단된다. CL-A, OS-A 지점은 월류보의 영향으로 저수위 일 경우에 상관관계가 낮았다. 수위-단면적, 평균유속-단 면적의 상관관계 및 곡선식 등을 이용하여 하천 정비계 획 등의 수립에 활용할 수 있으며, 제외지의 단면적이 변 하는 지점의 유량 변화 등의 예측에 활용할 수 있을 것 이다.

The flow rate analysis for sanitary fixtures has been studied to determine the water supply piping system and size. The study has been carried out to analyze for a various water supply pressure and piping size theoretically. Also, the study has been carried out to analyze for a various water supply piping system experimentally. The water supply pressure is varied from 0.01MPa to 0.07MPa, and the piping size is varied from 6mm to 15mm. The water supply piping systems are one-to-one, all-loop-type, and bathroom-loop-type water supply piping system. The results indicate that the piping size is able to supply water fully in case of smaller than 15mm if the water supply pressure keep an necessary minimum pressure. And the gap of flow rate is very little for the various water supply piping systems

The aim of this is to examine the effects of SSP therapy on the internal carotid arteries blood flow of 24 tension type headache patients(study group) and non tension type headache patients(control group), and on the reduction of their headaches, when applied to the acupuncture points. It stimulated the acupuncture point of headache 6 place with the SSP. It measured VAS and the blood flow of the internal carotid arteries with TCD. When the internal carotid arteries blood flow of study group and control group were compared by period, a significant difference was found in the 4th period(p<.05). When the Visual Analog Scale of study group and control group were compared by period, a significant difference was found in the 4th period(p<.05). The comparison of each measurement result of the internal carotid arteries blood flow of the study group found significantly increased. The comparison of each measurement result of the VAS of study group found significantly decreased. With regard to the control group, the VAS significantly decreased. The silver spike point low frequency electrical stimulation treatment, when applied to the acupuncture point, can significantly influence the internal carotid arteries blood flow of headache patients and can significantly reduce their headaches.

Aligned multi-wall carbon nanotubes (MWNTs) were synthesized through the catalytic decomposition of hydrocarbons in a quartz tube reactor. In this study, we investigated the influence of gas flow rate of feedstock on the structure and growth rate of vertically aligned carbon nanotubes produced by the floating catalyst method. As the flow rate of feedstock increased, the nanotube diameter became smaller and the length became longer. Although the growth rate also increased with the raise of flow rate, the optimum flow rate of feedstock existed for the crystallinity of carbon nanotubes.

Synthesis gas is a high valued compound as a basic chemicals at various chemical processes. Synthesis gas is mainly produced commercially by a steam reforming process. However, the process is highly endothermic so that the process is very energy-consuming process. Thus, this study was carried out to produce synthesis gas by the partial oxidation of methane to decrease the energy cost. The effects of reaction temperature and flow rate of reactants on the methane conversion, product selectivity, product ratio, and carbon deposition were investigated with 13wt% Ni/MgO catalyst in a fluidized bed reactor. With the fluidized bed reactor, CH4 conversion was 91%, and Hz and CO selectivities were both 98% at 850℃ and total flow rate of 100 mL/min. These values were higher than those of fixed bed reactor. From this result, we found that with the use of the fluidized bed reactor it was possible to avoid the disadvantage of fixed bed reactor (explosion) and increase the productivity of synthesis gas.

The effects of reaction temperature and flow rate of reactants on the methane conversion, product selectivity, product ratio, and carbon deposition were investigated with 13wt% Ni/MgO catalyst. Reaction temperatures were changed from 600 to 850℃, and reactants flow rates were changed from 100 to 200 mL/mim. There were no significant changes in the methane conversion observed in the range of temperatures used. It is possibly stemmed from the nearly total exhaustion of oxygen introduced. The selectiveties of hydrogen and carbon monoxide did not largely depend on the reaction temperature. The selectivities of hydrogen and carbon monoxide were 96 and 90%, respectively. Carbon deposition observed was the smallest at 750℃ and the largest at 850℃. It is found that the proper reaction temperature is 750℃. The best reactant flow rate was 150 ml/min.

nanopowder has been synthesized by means of the flame method using a precursor of titanium tetraisopropoxide (TTIP, Ti. In order to clarify the effect of cooling rate of hot flame on the formation of crystalline phases, the flame was controlled by varying the mixing ratio and the flow rate of gases. Anatase phase was predominantly synthesized under the condition having the steep cooling gradient in flame, while a slow cooling gradient enabled to form almost rutile nanopowder of above 95%

In this study, the recycling processes of construction and demolition waste (C&D waste) were analyzed, and its national recycling rate was determined using material flow analysis (MFA). Available statistical data provided by Ministry of Environment and Korea Environment Corporation were used for the MFA study. The collected data were carefully examined and validated by field investigations. System boundary for MFA covered from waste generation from construction sites to final disposal in 2013. The field investigation showed that recycled aggregate is produced through mechanical shredding, separation, and screening processes of C&D waste. The production efficiency (or process yield) was estimated to be approximately 81.2% on average. The foreign materials in the waste accounted for 18.8% by weight. The separated impurities were sent to recycling facilities, incineration facilities, or landfill sites, depending on the physicochemical characteristics. Efficiency of recycling facilities and the statistical data were integrated to estimate the national actual recycling rate, which turned out to be 87.7% in 2013. Approximately 49.1% of the construction-related waste was recycled as recycled aggregate for concrete production and road base layer for asphalt pavement. Based on the result of MFA, there is 9.8% difference between the actual recycling rate in this study and reported recycling rate by national statistics. In the future, more various C&D waste treatment and disposal facilities, along with aggregate recycling facility, should be investigated to verify the actual recycling rate determined by this study. Statistical accuracy should be further refined through additional field investigations. Our findings can be applicable to development of recycling policies and best management practices for C&D waste streams.

우리나라는 지형적인 특성과 높은 인구밀도로 인해 1인당 수자원 부존량이 부족한 상황이다. 이에 이상 기후현상과 여름에 집중되는 호우로 인한 가뭄이나 홍수에 효율적으로 대비하기 위해 2009년 하반기부터 4대강 사업이 추진되었고 2013년 현재 공사가 끝난 상황이다. 낙동강은 4대강 사업이 진행된 우리나라 주요 하천 중 사업이 진행된 길이가 가장 길고 수공구조물(보)이 가장 많이 설치되어 있다. 본 연구에서는 낙동강에 개설된 관측소들 중 다른 곳에 비해 지류의 유입이 적어 유량의 변화가 적고 그 사이에 수공구조물이 상대적으로 많이 설치되어 있는 낙동관측소와 왜관관측소를 연구대상으로 선정하였다. 보 설치 이전인 2009년 5,6,7월과 설치가 끝난 2013년 5,6,7월의 유량과 수위의 변화를 비교, 분석하여 수문변화에 대해 파악해 보았다. 수공구조물(보)가 설치되고 나서 상류(낙동관측소)와 하류(왜관관측소)간의 유량차가 감소하였고 상 하류 모두 강우량에 영향을 거의 받지 않고 낙동관측소와 왜관관측소에서 일정한 값의 수위를 유지하는 것을 알 수 있었다. 또한 최대 수위변화폭도 보 설치 이후인 2013년에 감소하였다. 이를 토대로 보 설치 이후 강우량에 의한 유량 및 수위변화가 적은 것으로 나타났으며 이상기후로 인해 발생하는 가뭄이나 홍수의 수문학적 영향이 적을 것으로 판단된다.