Jeong-Hyo Bae

Nitrate removal by electro-bioremediation technology in Korean soil.

The nitrate concentration of surface has become a serious concern in agricultural industry through out the world. In the present study, nitrate was removed in the soil by employing electro-bioremediation, a hybrid technology of bioremediation and electrokinetics. The abundance of Bacillus spp. as nitrate reducing bacteria were isolated and identified from the soil sample collected from a greenhouse at Jinju City of Gyengsangnamdo, South Korea. The nitrate reducing bacterial species were identified by 16s RNA sequencing technique. The efficiency of bacterial isolates on nitrate removal in broth was tested. The experiment was conducted in an electrokinetic (EK) cell by applying 20V across the electrodes. The nitrate reducing bacteria (Bacillus spp.) were inoculated in the soil for nitrate removal process by the addition of necessary nutrient. The influence of nitrate reducers on electrokinetic process was also studied. The concentration of nitrate at anodic area of soil was higher when compared to cathode in electrokinetic system, while adding bacteria in EK (EK+bio) system, the nitrate concentration was almost nil in all the area of soil. The bacteria supplies electron from organic degradation (humic substances) and enhances NO(3)(-) reduction (denitrification). Experimental results showed that the electro-bio kinetic process viz. electroosmosis and physiological activity of bacteria reduced nitrate in soil environment effectively. Involvement of Bacillus spp. on nitrification was controlled by electrokinetics at cathode area by reduction of ammonium ions to nitrogen gas. The excellence of the combined electro-bio kinetics technology on nitrate removal is discussed.

Evaluation of EK System by DC and AC on Removal of Nitrate Complex

Abstract DC (Direct current) is used in electrokinetic (EK) technology to extract hazardous materials from soils. Besides, AC (alternating current) electric field is also used to induce particle and fluid motion in electrokinetics. The influence of AC and DC on electrokinetic phenomena was studied for the removal of nitrate complex in soil environment. The experiments were performed by employing three systems – DC, AC, and AC overlapped DC. The removal of cations was higher at the anodic spot while applying DC. Involvement of AC on cation removal was very poor and nitrate removal was about 50%. AC and DC can be used for the removal of nitrate complex in agricultural soils.

The PMU interface using IEC 61850

As industry develops, the complexity of power networks will increase, which will place heavier demands on their reliable management. To increase the reliability of power networks, new technologies related to the operation of smart grids and micro grids are currently under development, and various intelligent devices are applied to control and monitor power networks. PMU is a microprocessor-based intelligent measuring device that has recently been used in various field and applications because of its high-resolution data information. Its main application is in wide-area power network monitoring and control. PMU is also used in applications in the fields of fault analysis and power quality analysis. Although PMUs high-resolution data is a main advantage, its large data make its interface, IEEE C37.118, difficult to handle.. C37.118 standard is used to interface PMU. It also describes on measurement requirements, measurements, error limits, data transmission, etc. It is also used to facilitate the effective transfer of large amounts of data and to describe the measuring reference of PMU. IEC 61850 is the communication interface standard for power facilities. Although it was developed for the system interface between power facilities for substation automation, its application field is growing rapidly. The IEC 61850 standard for the PMU interface has also developed as IEC 61850-90-5. Because most intelligent power facilities will be integrated via IEC 61850 standards, the development of a PMU interface using IEC 61850 has various advantages. For the development of management systems for powerful smart grid and micro grid, applications require much information, including static and dynamic data. Because PMU is an intelligent system that can provide time synchronized dynamic data, its interface with application systems will be very helpful in the design and development of control and monitoring systems. In this paper, we describe a PMU interface using IEC 61850 standards.

Effect of Electrode Materials on Electrokinetic Reduction of Soil Salinity

Laboratory electrokinetic (EK) tests were conducted for the restoration of saline soil which contained mainly Na+, Cl− and ions. The effect of anode materials on salt removal was investigated by comparing various anodes such as dimensionally-stable anode, Pt, Si/BDD (boron-doped diamond), and Fe electrode. In all tests Na+ and Cl− were easily removed from the soil (>97%). Fe tests showed higher reduction of concentration and resulted in higher electrical conductivity reduction (∼90%) than the other anode tests. The results demonstrated that the EK process can reduce soil salinity effectively and the Fe anode is more suitable for restoration of sulfate-rich saline soil than other insoluble anodes.

Analysis of voltages induced by distribution lines on gas pipelines

Because of the continuous growth of energy consumption and the tendency to site power lines and pipelines along the same route, the close proximity of power lines and buried metallic pipelines has become more and more frequent. Therefore, there has been and still is a growing concern about possible hazards resulting from the influence of power lines on metallic pipelines. Underground pipelines that run parallel to or in close proximity to power lines are subjected to induced voltages caused by the time-varying magnetic fields produced by the power line currents. The induced electro-motive force causes currents circulation in the pipeline and voltages between the pipeline and surrounding earth. This paper analyses the induced voltage on the gas pipelines buried in parallel with overhead power distribution lines.

Development of JPEG 2000 simulator and image quality analysis on bit plane coding

JPEG 2000 is new standard and it has various useful features. Bit plane coding is JPEG 2000s new coding scheme and by using it, JPEG 2000 can provide various new additional functions like high resolutions image compression, progressive transmission and scalable coding of image, etc. Because bit plane coding is one of key functional block and it play important role in JPEG 2000, we want to analyze its effect on image quality. To do so, we developed JPEG 2000 simulator including forward and inverse transform block, bit plane coding block, Tier-2 Encoder block, etc. By using it, we analyzed JPEG 2000s characteristics, changing number of bit planes and quantization step size. In this paper, we describe on image quality analysis for JPEG 2000s bit plane coding.

Data logger apparatus for stray current measurement of subway and power line

In present, most of metallic structures (gas pipeline, oil pipeline, water pipeline, etc) are running parallel with subway and power line in Korea. Moreover subway system and power line make a stray current due to electrical corrosion on metallic structures. The owner of metallic structures has a burden of responsibility for the protection of corrosion and the prevention against big accident such as gas explosion or soil pollution and so on. So, they have to measure and analyze the data about P/S(Pipe to Soil) potential, amplitude of stray current, point of source of stray current and so. In this paper, results of development about data logger apparatus for measurement stray current of subway and power line are presented.

Electrochemical and Optical Characterization of the Corrosion Resistivity of Explosively Bonded Al-Cu Bimetal

With the usage of Al-Cu bimetals to connect aluminum and copper in power distribution systems growing persistently, efforts to mitigate the mechanical, electrical and electrochemical degradation are widely made. The explosive bonding technology has been considered as a countermeasure for the degradation. In this paper, electrochemical analysis and optical microscopic observation are carried out in order to compare the corrosion resistivity of the explosion type bimetal to the commonly used compression type bimetal. In particular, the effect of anions in the interfacial electrolyte on corrosion susceptibility was also investigated. The results show that the explosive bonding technology can prevent the interfacial corrosion caused by the formation of crevices and pits as well as by galvanic potential difference between aluminum and copper.

A Study on the Power Management Algorithm of Centralized Electric Vehicle Charging System

As Plug-in Hybrid Vehicle and Electric Vehicle (PHEV/EV) take a greater share in the personal automobile market, their high penetration levels may bring potential challenges to electric utility especially at the distribution level. Thus, there is a need for the flexible charging management strategy to compromise the benefits of both PHEV/EV owners and power grid side. There are many different management methods that depend on the objective function and the constraints caused by the system. In this paper, the schema and dispatching schedule of centralized PHEV/EV charging spot network are analyzed. Also, we proposed and compared three power allocation strategies for centralized charging spot. The first strategy aims to maximize state of vehicles at plug-out time, the rest methods are equalized allocation and prioritized allocation based on vehicles SoC. The simulation results show that each run of the optimized algorithms can produce the satisfactory solutions to response properly the requirement from PHEV/EV customers.

Rapid potential-controlled rectifier for securing the underground pipeline under electrolytic interference

In electrolytic interference circumstances such as underground pipelines in the vicinity of DC rail transportation power systems, either drainage methods or ICCP method has been widely used in order to secure the integrity of the pipelines. The drainage method is applied either by forced drainage system in which the driving voltage for draining the stray current from the pipelines is controlled by thyristors or by polarized drainage system which connects the pipeline with the railroads by diodes. In ICCP method, the phase-controlled rectifier with thyristors is in common use. Both methods, however, cannot respond to the dynamic fluctuation of the stray current. As a result, the pipe-to-soil potentials of the pipelines near railroads vary rapidly and therefore a new counter measure with dynamic response is necessary. In this paper, we introduce a new rapid potential-controlled rectifier consisting of full bridge circuits for bidirectional power output and IGBT switching device. Field test comparison with the existing forced drainage method showed the effectiveness of the developed rectifier for securing the pipelines under electrolytic interference.