• Journal of Soil and Groundwater Environment
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• v.7 no.2
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• pp.13-22
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• 2002

Soil washing by surfactants is a technology to enhance mobilization and subsequent degradation of oil pollutants by reducing the surface tension of pollutants which is combined with soil. In this study, biosurfactant, rhamnolipid was produced from Pseudomonas aemginosa ATCC 9027 which had an excellent biodegradable activity in soil without causing secondary pollution. Effects of chemical surfactants on the removal of diesel from diesel-contaminated soil were compared to those of biosurfactants including rhamnolipid. Diesel removal efficiency by rhamnolipid extracted from P. aeruginosa culture broth was over 95% in both batch and column washing test in 5,000ppm diesel-contaminated soil with 1% surfactants after washing for 24 hours. On the contrary, the results of chemical surfactants were below 50∼80%, The chemical surfactants with HLB value(8∼15) showed more then 75% efficiency of diesel removal. But, when the HLB values were below 8 or over 15. their efficiency were observed as less then 60% of diesel removal. Rhamnolipid, biologically produced surfactants, may also be promising agent for enhancing diesel removal from contaminated soil.

• Magazine of the Korea Concrete Institute
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• v.8 no.3
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• pp.197-207
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• 1996

Maturity is expressed as the integral of time and temperature of concrete above a datum temperature. The maturity concept proposes that concrete of the same mix at the same maturity has the same strength, whatever combination of temperature and time makes up that maturity. In this study, the Nurse-Saul function which was proposed to account for the effects of temperature and time on strength developrnent is used in computing maturity. After existing various functions are considered to relate concrete strength to the maturity value, new strength-maturity function is proposed. Tests ;ire conducted in order to determine d datum temperature and compare prechction value with measured concrete strength. The constants in proposed prediction equation are determined from test results, and the equation is adopted to predict the strength of slab. The slab was cast in the laboratory from the same batch of mold, and cores are cut from slab in order to estimate the actual strength. These values are used to compare with predicted value. The present study allows more realistic determination of early-age strength of concrete and can be efficiently used to control the quality in actual construction.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.588-594
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• 2005

We have investigated Y zeolite and activated carbon for an adsorptive desulfurization of diesel. In batch experiments, cation ($Cu^{2+}$, $Ni^{2+}$) exchanged Y zeolites showed high equilibrium adsorption capacity for sulfur compounds in model diesel, which contained BT, DBT and 4,6-DMDBT of each 50 ppmw in n-octane. But the cation exchanged Y zeolites lost its capacity in commercial diesel (186 ppmw). On the other hand, activated carbon showed reasonable adsorption capacity for sulfur compounds in both model and commercial diesel. The adsorption capacity of sulfur on Ni-Y zeolite was decreased with the increase of benzene concentration in model diesel but the sorption capacity on activated carbon was insensitive to aromatic concentration. In breakthrough test, activated carbon of 1 g could treat 15 ml of commercial diesel with 186 ppmw sulfur. Toluene showed good solvent for regenerating activated carbon among several solvents.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.3
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• pp.383-388
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• 2006

SBR is one of the most general sewage/wastewater treatment processes and, particularly, has an advantage in high concentration wastewater treatment like sewage wastewater. A Kernel PCA based fault diagnosis system for biological reaction in full-scale wastewater treatment plant was proposed using only common bio-chemical sensors such as ORP(Oxidation-Reduction Potential) and DO(Dissolved Oxygen). During the SBR operation, the operation status could be divided into normal status and abnormal status such as controller malfunction, influent disturbance and instrumental trouble. For the classification and diagnosis of these statuses, a series of preprocessing, dimension reduction using PCA, LDA, K-PCA and feature reduction was performed. Also, the diagnosis result using differential data was superior to that of raw data, and the fusion data show better results than other data. Also, the results of combination of K-PCA and LDA were better than those of LDA or (PCA+LDA). Finally, the fault recognition rate in case of using only ORP or DO was around maximum 97.03% and the fusion method showed better result of maximum 98.02%.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.4
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• pp.269-275
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• 1993

The performance of Upflow Anaerobic Sludge Blanket(UASB) reactor for treatment of corn starch wastewater was investigated using continuous and batch experiment. Results showed that the corn starch wastewater had different characteristics in terms of biodegradability and methane potential, depending on the manufacturing precess. COD removal efficiencies were maintained over 70% up to the loading rate of 3.2 kg $COD/m^3{\cdot}day$ and the maximum gas production rate was about 55 l/day, equivalent to 3.5 l/day per liter of reactor volume, at the loading rate of 8.4 kg $COD/m^3{\cdot}day$. In the anaerobic serum bottle test(SBT) carried out along with continuous operation, the sludge activity was found to increase from 0.03 to 0.53 g $COD-CH_4/g\;VSS{\cdot}day$ as granular sludges were developed in 130 days operation. SBT gave valuable informations on the characteristics of wastewaters to be treated as well as on the sludge activity. The overall morphological characteristics of granular sludges cultivated on corn starch wastewaters were similar to those cultivated on various organic industrial wastewaters such as distillery and sugar.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.2
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• pp.1-10
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• 2016

In this paper, we present a new way to derive the mean cycle time of the G/G/m failure prone queue when the loading of the system approaches to zero. The loading is the relative ratio of the arrival rate to the service rate multiplied by the number of servers. The system with low loading means the busy fraction of the system is low. The queueing system with low loading can be found in the semiconductor manufacturing process. Cluster tools in semiconductor manufacturing need a setup whenever the types of two successive lots are different. To setup a cluster tool, all wafers of preceding lot should be removed. Then, the waiting time of the next lot is zero excluding the setup time. This kind of situation can be regarded as the system with low loading. By employing absorbing Markov chain model and renewal theory, we propose a new way to derive the exact mean cycle time. In addition, using the proposed method, we present the cycle times of other types of queueing systems. For a queueing model with phase type service time distribution, we can obtain a two dimensional Markov chain model, which leads us to calculate the exact cycle time. The results also can be applied to a queueing model with batch arrivals. Our results can be employed to test the accuracy of existing or newly developed approximation methods. Furthermore, we provide intuitive interpretations to the results regarding the expected waiting time. The intuitive interpretations can be used to understand logically the characteristics of systems with low loading.

• Journal of Korea Soil Environment Society
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• v.1 no.2
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• pp.61-72
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• 1996

A series of batch and lab-scale continuous tests were conducted to optimize the design parameters for the full-scale in-situ soil flushing experiments. The cleaning abilities of the surfactant solutions of Tween 80, Triton X-100 and SDS were compared for the soil artificially contaminated by hydrophobic organic contaminants: n-dodecane, naphthalene and anthracene. Tween 80 and Triton X-100 were shown to be efficient for n-dodecane. SDS and Tween 80 were shown to be efficient for naphthalene and anthracene. At the end of each column test, the sorbed amount of surfactant to soil was also measured. Tween 80 was found to be the least adsorbed surfactant to soil. The flushing ability at flowrate of 7 ml/min, was hampered comparing to flowrate of 3 and 5 ml/min. Initial pH of the soil did not significantly affect the flushing efficiencies. Tween 80 was determined as the most harmless surfactant for the Gram(+) and Gram(-) bacteria.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.6 no.4
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• pp.29-42
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• 1986

This study is an experimental research on the adsorption capacity and the adsorption system utilizing Discarded Automotive Tires(DAT) and Powdered or Granular Activated Carbon(PAC or GAC) for the removal of heavy metals, Ag(I), Cd(II), Cu(II), Zn(II). Batch shaking test was conducted to determine the adsorption capacity of DA T and PAC in removing the heavy metals from aqueous wastes; and laboratory-scale column experiment was performed to present design factors affecting the optimum design of adsorption column with DAT and GAC, through the concept of Bed Deph/Service Time(BDST). As results, DAT has been proven to be a good adsorbent will its adsorption capacity not falling behind PAC or GAC. Factors affecting heavy metals removals were amount of adsorbents, initial concentrations, pH and so on. BDST equations were compared with values presented by the breakthrough data from adsorption system.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.529-532
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• 2006

The application of ubiquitous technology offers many chances for improving construction management technologies. Currently the Construction System Integration Lab (CSIL) at Pusan National University is executing research on applying ubiquitous technology for better communication in the construction process. One of the research area is the implementation of RFID for monitoring the concrete pour process. The objective of this study is to collect data occurring in the process and use the data be properly planning concrete pour activities. Case study has been done on an actual concrete work. For the study a user environment was developed interfacing on internet with RFID devices that were installed in a batch plant and a construction site. The result of the test demonstrated that the RFID-based concrete monitoring can be a feasible approach for improving the communication in the construction process.

• Journal of Power Electronics
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• v.13 no.4
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• pp.516-527
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• 2013

This paper presents a new overall system for state-of-available-power (SoAP) prediction for a lithium-ion battery pack. The essential part of this method is based on an adaptive network architecture which utilizes both fuzzy model (FIS) and artificial neural network (ANN) into the framework of adaptive neuro-fuzzy inference system (ANFIS). While battery aging proceeds, the system is capable of delivering accurate power prediction not only for room temperature, but also at lower temperatures at which power prediction is most challenging. Due to design property of ANN, the network parameters are adapted on-line to the current battery states (state-of-charge (SoC), state-of-health (SoH), temperature). SoC is required as an input parameter to SoAP module and high accuracy is crucial for a reliable on-line adaptation. Therefore, a reasonable way to determine the battery state variables is proposed applying a combination of several partly different algorithms. Among other SoC boundary estimation methods, robust extended Kalman filter (REKF) for recalibration of amp hour counters was implemented. ANFIS then achieves the SoAP estimation by means of time forward voltage prognosis (TFVP) before a power pulse occurs. The trade-off between computational cost of batch-learning and accuracy during on-line adaptation was optimized resulting in a real-time system with TFVP absolute error less than 1%. The verification was performed on a software-in-the-loop test bench setup using a 53 Ah lithium-ion cell.