• 환경위생공학
• /
• 제16권2호
• /
• pp.1-8
• /
• 2001

The water treatment by electrochemical method was performed to increase the yield of production. Continuous plug flow reactor was operated to treat poultry and domestic wastewaters. Experimental results were compared with experimental results of the wastewater treatment by chemical coagulation, they were increased over 10% in the removal efficiency of COD and the production rate of sludge was reduced by 30%. Ozone utilized to degrade or change the organic chemical structures, which removal efficiency increased to 20% in the electro-coagulation reactor. Economic evaluation was performed to estimate total cost of electro-coagulation reactor in comparison with that of chemical coagulation method. The total cost to treat 1000 ton/day of domestic wastewater was reduced by 50%.

• Environmental Analysis Health and Toxicology
• /
• 제4권3_4호
• /
• pp.29-59
• /
• 1989

For the purpose of electrolytic treatment of wastewater containing various heavy metals, the BPBE Cell of batch and continuous type was considered and experimented. Some results from this study were summarized as follows: 1. When the artificial wastewater containing 500 mg/l of the concentration of various heavy metallic ion was electrolyzed in BPBE Cell of batch type, the removal efficicency was over 95% in cadmiun (II), lead (II), chromium (Ⅵ) and over 85% in copper (II), chromium (III). 2, As granular activated carbon packed in BPBE Cell, coconut shell was superior to lignite and the removal efficiency was the highest when the activated carbon was 4/6 mesh, the voltage was 20V. 3. When the heavy metallic ion in wastewater was electrolyzed in BPBE Cell of continuous type, about 1,000mg of heavy metal per 1kg of coconut sell could be removed. 4. The treatment method of heavy metallic ion in wastewater by BPBE Cell cost less than in the former chemical treatment method and the coconut shell packed in BPBE Cell could be regenerated by chemical method.

• 한국재료학회지
• /
• 제21권1호
• /
• pp.39-45
• /
• 2011

In this study, the heat flow of the plant scale aluminum extrusion process was investigated to establish optimum continuous heat treatment conditions. During the extrusion of 6061 aluminum alloy, processing parameters such as the extrusion pressure, speed and temperature histories of billets were logged as a function of time. The surface temperature of the billets increased at constant ram speed, while it decreased with decreases of the ram speed. In order to maintain the billet temperature within a solutionizing temperature range prior to the succeeding water quenching step, the ram speed or the temperature of the blower should be controlled. The temperature histories of the billets during the extrusion and hot air blowing processes were successfully simulated by using the velocity boundary model in ANSYS CFX. The methodology to design an optimum process by using a commercial simulation program is described in this study on the basis of the metallurgical validation results of the microstructural observation of the extrudates. The developed model allowed the advantages of taking into account the motion of the extrudate coupled with the temperature change based on empirical data. Calculations were made for the extrudate passing through the isothermal chamber maintained at appropriate temperature. It was confirmed that the continuous heat treatment system is beneficial to the productivity enhancement of the commercial aluminum extrusion industry.

• The Korean Journal of Pain
• /
• 제24권3호
• /
• pp.169-171
• /
• 2011

Postherpetic neuralgia is the most frequent complication of herpes zoster. Treatment of this neuropathic pain syndrome is difficult and often disappointing. Although postherpetic neuralgia is generally a self-limited condition, it can last indefinitely. Continuous epidural blockade for patients with acute zoster can shorten the duration of treatment. However, continuous epidural block has some complications such as infection, dural puncture, and total spinal and nerve damages. We report a case of myoclonus during continuous epidural block with ropivacaine, morphine, and ketamine in an acute zoster patient.

• 한국정밀공학회지
• /
• 제15권4호
• /
• pp.58-67
• /
• 1998

A sectional analysis of sheet metal forming process with an arbitrary tool shape is proposed in the present work. To improve the numerical convergence in the conventional membrane sectional analysis, the Bending Energy Augmented Membrane (BEAM) elements had been developed. The BEAM elements particularly improve the stability and convergence of the finite element method for the case of deep drawing. In this work, the FERGUBON spline (C$^2$-continuous) was used to fit the deformed mesh to smooth the given curves and calculate the local curvature of the deformed sheet. The fittings of the deformed sheet and tool surface profile ensure the stability and the convergence of the finite element analysis of highly nonlinear stamping processes. A center floor section and front fender section are analyzed to show the accuracy and robustness of the approach. The results obtained by the proposed approach are compared with the available experimental data.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.1515-1517
• /
• 2008

The purposes of this study were to measure the ranges of motion in knee joint and during continuous passive motion(CPM) treatment and to computationally calculate joint angles at the knee joint dependent on the CPM machine design and its application. Four CPM machines and eleven candidates were recruited for this study. Experimental and numerical studies have been peformed to calculate the range-of-motion of CPM machines. From the experimental measurements, the average range of motions at the knee joint for the CPM machine #1, #2, #3, and #4 were lower than the manufactures suggested values due to improper alignments of the hip and knee joints to the CPM machines. Different design of CPM machine generated different outcomes of the ROM at the knee joints during CPM. The experiments and kinematic simulation in this study could be used to provide useful guidance in the treatment of CPM after joint surgery.

• 한국안전학회지
• /
• 제8권4호
• /
• pp.127-132
• /
• 1993

Porphyrin-catalyzed reduction of TNT to triaminotoluene was performed in both batch reactions and a continuous process. Packed-bed reactors were used to study porphyrin-catalyzed reduction in a continuous process. A reactor was packed with DEAD(diethylaminoethyl)-substituted glass beads on which $Co^{+3}$_centered deuteroporpgyrin Ⅸ, -2, 4-disulfonic acid was immobilized, and another containing only DEAE glass beads was used as a control. The porphyrin exhibited catalytic activity in its immobilized state up to 100 hours of operation. Based on the successful abatement of nitrobodies by porphyrin-catalyzed reduction in both batch and continuous process, this process is recommended to be used as a pretreatment for biological treatment or carbon adsorption treatment of TNT wastes.

• 한국초전도ㆍ저온공학회논문지
• /
• 제24권3호
• /
• pp.12-18
• /
• 2022

In recent years, the impact of microplastics (MPs) on ecosystems is a serious problem. Since MPs are difficult to recover once they are dispersed into the environment, it is important to remove them at the source. We proposed a magnetic separation of primary MPs (plastics manufactured in minute sizes) sized 10-100 ㎛ that has not been removed in the sewage process, based on the magnetic seeding process. In this study, we used magnetite as a magnetic seeding agent, and conducted magnetic separation experiments in the continuous process using a superconducting solenoidal magnet to investigate the feasibility of practical magnetic separation system of MPs. As a result, 85% separation rate was obtained by continuous separation using high gradient magnetic separation (HGMS) with hydrophobically treated magnetite as a magnetic seeding agent.

• 상하수도학회지
• /
• 제11권2호
• /
• pp.94-104
• /
• 1997

Ozone Treatment is getting a common process in a water treatment plant all over the nation. Especially an advanced water treatment using ozone and biofiltration has been a typical method in the regions where using the Nak-Dong River as a drinking water source. The effectiveness of ozone treatment in a continuous flow contact system was investigated with sand filtered water of the Nak-dong River. Pilot tests of the experiments were performed three times of the year like June, August, and October 1995. Most degradable organics of sand filtered water were oxidized in the first and second contact chamber of the system. Ozone treatment was effective for the removal of UV254 absorbance. However, Noticeable removals of $KMnO_4$ demand and TOC(Total Organic Carbon) were occurred when their concentrations exceeded about 5mg/l. The organics causing $KMnO_4$ demand and TOC were degraded into lower molecular matter in an early stage of the ozone contact in the system. Dissolved oxygen concentration was increased after ozone treatment.

• 한국환경과학회지
• /
• 제28권5호
• /
• pp.495-502
• /
• 2019

This study was conducted to investigated the possibility of inactivating wilt germs (Fusarium oxysporum f. sp. radicis lycopersici) using Dielectric Barrier Discharge (DBD) plasma in a hydroponic system. Recirculating hydroponic cultivation system for inactivation was consisted of planting port, LED lamp, water tank, and circulating pump for hydroponic and DBD plasma reactor. Two experiments were conducted: batch and intermittent continuous process. The effect of plasma treatment on Total Residual Oxidants (TRO) concentration change, Fusarium inactivation and growth of lettuce were investigated. In the batch experiment, most of the Fusarium was inactivated at a TRO concentration of 0.15 mg/L or more at four-day intervals. There was no change in lettuce growth after two times of plasma treatment for one week. The intermittent continuous experiment consisted of 30-minute, 60-minute, and 90-minute plasma treatment in 2 day intervals and 30-minute treatment a one-day; most of the Fusarium was inactivated only by treatment for 30-minute every two days. However, if inactivation under $10^1CFU/mL$ is required, it will be necessary to treat for 60 minutes in 2 day intervals. The plasma treatment caused no damage to the lettuce, except the 30 min plasma treatment ay the one-day interval. It was considered that the residual TRO concentration was higher than that of the other treatments.