• 센서학회지
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• 제32권3호
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• pp.174-179
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• 2023

Bulk trailers, used for the transportation of powdered materials, such as cement and fly ash, are crucial in the construction industry. The speedy exhaustion of powdered materials stored in the tank of bulk trailers is relevant to improving transportation efficiency and reducing transportation costs. The exhaust time can be reduced by developing an automatic control system to replace the manual exhaust operation. The instantaneous or accumulated exhausts of powdered materials must be measured for automatic control of the bulk trailer exhaust system. Accordingly, we previously proposed a recurrent neural network (RNN) model that estimated the instantaneous exhaust based on low-cost pressure sensor signals without an expensive flowmeter for powders. Although our previous study utilized only an RNN model, models such as multilayer perceptron (MLP) and convolutional neural network (CNN) are also widely utilized for time-series estimation. This study compares the performance of three neural network models (MLP, CNN, and RNN) in estimating instantaneous and accumulated exhausts. In terms of the instantaneous exhaust estimation, the difference in the performance of neural network models was insignificant (that is, 8.64, 8.62, and 8.56% for the MLP, CNN, and RNN, respectively, in terms of the normalized root mean squared error). However, in the case of the accumulated exhaust, the performance was excellent in the order of CNN (1.67%), MLP (2.03%), and RNN (2.20%).

• 한국분무공학회지
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• 제23권3호
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• pp.128-135
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• 2018

In this study, the following conclusions could be obtained from the analysis of emissions contribution rates and features for contaminated emissions by 13,456 gasoline vehicles passed in the vehicle load test (ASM-idle) under the inspection year 2013 to 2017. It was confirmed that the contamination of the CO, HC, NOx by the displacement is reduced on over 3L engine. As a result of comparing the exhaust gas in the low speed idle mode and the AS2525 mode, the exhaust gas in the low speed idle mode was measured high. It is estimated that if ISG function is applied, emissions from idle condition will be reduced. NOx emissions were reduced when the engine power was above 200HP. It has been confirmed that the amount of exhaust emissions are significantly reduced for vehicles manufactured after 2004. As a result of analyzing the exhaust gas according to the season, it is judged that there is a correlation between HC and NOx according to the ambient temperature. The concentration of exhaust emission in vehicles with high accumulated distance increases, which is considered to be the result of aging of the vehicle.

• 오토저널
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• 제10권5호
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• pp.54-60
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• 1988

This study is a theoretical analysis and experimental effect of oxygen concentration, exhaust velocity and trap inlet temperature on particulate ignition temperature with installation of ceramic filter trap in diesel engine. So the following results are obtained. 1, Based on the fundamental experiments of the regeneration process, the analytical model was developed and the results from the analytical model agreed with the experiments, then the validity of the model was proved. 2, The ignition temperature for accumulated particulate was proportional to the exhaust velocity and it was known that the optimum exhaust velocity was about 15m/sec. 3, The ignition temperature for accumulated particulate was inversely proportional to the oxygen concentration and the trap inlet temperature, and a minimum oxygen concentration of 5% was required to sustain regeneration. 4, This experimental filter trap(EX-66) is found about 30% of smoke reduction efficiency in comparison with existing muffler.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.464-469
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• 2012

발전소에 있어서, 발전소가 높은 신뢰성이 있기 위해서는 안정적인 회전체의 동적 운동이 확보되어야 하므로, 장기간 안전하게 운전하기 위하여 축 진동은 매우 중요한 요소중의 하나이다. 하지만 어느 복합발전소에서는 오일 탄화물에 의한 비정상적인 1X 성분의 축 진동 상승으로 가스터빈이 여러번 정지되었다. 본 논문에서는 가스터빈 Exhaust 케이싱 베어링에서 발생한 이상진동에 대하여 어떻게 현장조치를 하였는지를 기술하였다.

• Asian Journal of Atmospheric Environment
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• 제1권1호
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• pp.28-35
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• 2007

Accumulated epidemiological and animal studies have suggested that prolonged exposure to ambient particulate matter (PM) is associated with an increased risk of cardiovascular disease and pulmonary dysfunction. While diesel exhaust particles (DEP) contain large variety of compounds, polycyclic aromatic hydrocarbons (PAHs) are a dominant component contaminated in DEP. This article reviews effects of two PAH quinones, 9,10-phenanthraquinone (9,10-PQ) and l,2-naphthoquinone (l,2-NQ), on vascular and respiratory systems.

• International Journal of Automotive Technology
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• 제3권1호
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• pp.41-46
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• 2002

Effect of secondary air injection (SAI) on hydrocarbon reduction has been investigated in a single cylinder Sl engine operating at cold-steady/cold-start conditions. The hydrocarbon emission and exhaust gas temperature with and without catalytic converter were compared with continuous and synchronized SAIs, which injected secondary air intermittently into exhaust port. Effects of SAI location, SAI pressure, SAI timing, and location of catalytic converter have been investigated and the results are compared for both SAls with base condition. At cold-steady condition, the rate of HC reduction increased as the location of SAI was closer to the exhaust valve for both synchronized and continuous SAls. The emission of HC decreased with increasing exhaust-A/F when it was rich, and was relatively insensitive when it was lean. The timing of SAI in synchronized SAI had significant effect on HC reduction and exhaust gas temperature and the synchronized SAI was found to be more effective in HC reduction and exhaust gas temperature compared to the continuous SAI . At cold-start condition, when the catalytic converter was located 20 cm downstream from the exhaust port exit, the catalytic converter warm-up period for both SAls decreased by about 50%, and the accumulated hydrocarbon emission during the first 120 s decreased about by 56% and 22% with the synchronized and continuous SAIs, respectively, compared to that of the base condition.

• 생명과학회지
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• 제17권10호
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• pp.1414-1418
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• 2007

3가지 농도의 납을 첨가한 토양에서 생장한 애기장대(Arabidopsis thaliana)에서 식물체에 축적된 납의 농도를 조사하였다. 환경부 고시 오염물질 배출기준 농도(1 mg/l)와 10배 높은 농도(10 mg/l) 및 50배 높은 농도(50 mg/l)의 납이 첨가된 토양에서 생장한 식물의 줄기에 축적된 납의 농도는 3가지 농도에서 증가율이 유사하게 나타났으며, 정상식물 줄기에 비하여 평균 약 24% 증가하였다. 3가지 농도의 납이 첨가된 토양에서 생장한 식물의 잎에 축적된 납의 농도는 정상식물 잎에 비하여 평균 약 57% 증가하였으며, 줄기와 마찬가지로 토양에 첨가된 납의 농도 증가에 따라 잎에 축적된 납의 농도는 유의한 차이는 나타나지 않았으며 증가율도 유사하였다. 반면 오염물질 배출기준 농도와 10배 높은 농도의 납이 첨가된 토양에서 생장한 식물의 뿌리에 축적된 납의 농도는 정상식물 뿌리에 비하여 평균 약 114% 증가하였으나, 50배 높은 농도에서는 약 861% 증가하여 줄기나 잎과는 대조적인 결과를 나타내었다. 토양 속에 첨가된 납의 농도가 증가하면 애기장대 식물체 내에 축적된 납의 농도도 증가하였는데, 특히 오염물질 배출기준농도보다 50배 높은 납이 첨가된 토양에서 생장한 식물체내에 축적된 납 농도는 정상식물보다 약 2.6배 증가하였다. 이러한 결과는 토양 속에 오염된 납은 식물의 줄기나 잎보다는 뿌리에 더 많이 축적되며, 줄기와 잎에 축적되는 납 농도는 토양 속에 오염된 납 농도에 비례하여 증가하지 않으나 뿌리에서는 농도에 비례하여 매우 증가하였음을 나타내고 있다.

• 한국자동차공학회논문집
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• 제9권2호
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• pp.67-74
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• 2001

A synchronized secondaty air injection method has been developed to hydrocarbon emission by injecting secondary air intermittently into exhaust port. The method has been tested in a single cylinder spark-ignition engine operating at cold-steady / cold-start conditions. Effects of air injection timing, intake pressure and engine air-fuel ratio have been investigated at cold-steady condition. Also, hydrocarbon emission and exhaust gas temperature with catalytic conberter are compared with a continuous SAI method and base condition at cold-start condition. Resules show that hydrocarbon reduction rate and exhaust gas temperature are sensitive to the timing of synchronized SAI. At cold-steady condition, HC emission is minimum at engine air-fuel ratio of 10. At cold-start condition, the accumulated hydrocarbon emission during the first 120 s decreases about 56% and 22% with the synchronized and continuous SAI, respectively, compared to that of base condition.

• Journal of Advanced Marine Engineering and Technology
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• 제23권2호
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• pp.184-191
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• 1999

Th effects of exhaust gas recirculation(EGR) on the characteristics of combustion exhaust emissions and specific fuel consumption(SFC) are experimentally investigated by four-cylin-der four-cycle and direct injection marine diesel engine. In order to reduce soot contents in the recirculated exhaust gas to intake system of the engines a novel diesel soot removal system with a cylinder-type scrubber which has water injector(4 nozzles in 1.0mm diameter)is specially designed and manufactured for the experi-mental system. The obtained results are as follows; The combustion pressure in cylinder is decreased and ignition is delayed with increasing EGR rate. The accumulated quantity of heat release is slightly decreased and the tendency of heat release rate is not constant. NOx and Soot emissions are decreased by maximum 7% and 540% with scrubber tan without scrubber in the range of experimental conditions. Those are increased at the lean burn area with increasing equivalence ration in the constant value of engine speed and EGR rate. Also those are decreased with increasing EGR rate in the constant value of engine speed and equivalence ratio.

• 한국자동차공학회논문집
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• 제2권5호
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• pp.58-65
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• 1994

In order to reduce particulate emissions from diesel vehicles, mathematical model is established and analyzed on ceramic wall-flow monolith filter. A wall-flow monolith filter placed in the exhaust stream of a diesel engine can effectively limit the emission of diesel particulates through the monolith. The accumulated particulates can then be periodically combusted inside the monolith by directing hot gas to the monolith while normal engine exhaust is routed around the monolith system. The resulting low flow rates through the monolith require consideration of gas dynamics through the channels as well as particulate combustion to analyze this regeneration process. A mathematical model of the regeneration is formulated as a system of nonlinear partial differential equations describing the conservation of mass, momentum and energy. Numerical solutions are obtained by using a finite difference techniques for the spatial discretization. So we can use filter simulation program for the purpose of filter design and actual filter regeneration