• Environmental Engineering Research
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• v.22 no.2
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• pp.210-215
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• 2017

Produced water is the largest wastestream of oil and gas exploration. It consists of various organic and inorganic compounds that hinder its beneficial use. This study compared the treatment of produced water in a batch suspended and biofilm activated sludge process. The biofilm carrier material was made from Gardenia Carinata shell. COD, $NH_4{^+}-N$ and $NO_3-N$ removal was monitored in both the suspended (control) and floating carrier bioreactors. The results show a rapid reduction of produced water constituents in the floating carrier bioreactor. COD, $NH_4{^+}-N$ and $NO_3-N$ removal was in the range of 99%, 98% and 97% for the floating carrier bioreactor whereas it was 88%, 84% and 83% for the control bioreactor. The rapid reduction of COD, $NH_4{^+}-N$ and $NO_3-N$ clearly indicate that the floating carrier materials served as an attached growth medium for microorganisms, improved the breakdown of produced water constituents and reduced inhibition of microbial metabolic activities.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.37-38
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• 2007

It needs several large reservoirs and long time to remove suspended solid like steel fines and iron oxide in hot rolling coolant. If removing rate of suspended solid in rolling coolant is improved by using high gradient magnetic separation (HGMS) system, the productivity of working process can be increased and the area of reservoir can be reduced. Pre-treatment process that react magnetic floc with inorganic and organic flocculant in coolant was studied. Horizontal type superconducting HGMS system was manufactured successfully, which was constituted with automatic filter transportation apparatus, 6 T He-free superconducting magnet system and water circulation system. The solid suspension removal ratio in hot rolling coolant was increased by flocculation with inorganic and organic flocculant.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.4
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• pp.890-894
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• 1999

Microencapsulation of anchovy oil as a core material in sodium alginate as a wall material was inves tigated. Microencapsulation was accomplished by injecting an oil/water emulsion, consisting of a mixture of liquefied sodium alginate and emulsifier, under high pressure through an orifice submerged in a calcium lactate solution. Microcapsules suspended in a dispersion fluid were observed under a fluorescence mi croscope to verify the presence of the capsules and to note coalescence or degradation of the capsules. Optimum conditions for microencapsulation of anchovy oil were obtained when 1.0% aqueous solution of sodium alginate contained 3% of a 1:1 ratio of ESPR 25(polyglycerine＋polylinoleate) and TW 20(sorbitan laurate＋ethylene oxide) as an emulsifier in terms of capsule size and size distribution, and emulsion stability. The airless sprayer produced microcapsules with a diameter between 15.9 and 73.9 m with different concentration of a wall material. The optimum mixing ratio of wall material to core material was 90:10(wt/wt). 0.2% calcium lactate was appropriate as a dispersion fluid.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.393-396
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• 1996

This paper studies electrostatically suspended induction motors (ESIM). The ESIM possesses the rotating ability of an ordinary electrostatic induction motor, in addition to providing contactless support by electrostatic suspension. To accomplish these two functions, a feedback control strategy and the operating principle of an ordinary electrostatic induction motor are used. The stator possesses electrodes which exert the electrostatic forces to the rotor and are divided into a part responsible for suspension and one for rotation. Two rotor types are utilized: a polished glass disk without any surface treatment, and a polished glass disk covered with a thin layer of conductive material (ITO layer) on only one side. In this paper, the principle of the ESIM is described, followed by stator electrode design, experimental apparatus, control strategy for stable suspension. Experimental results show that the glass disk has been rotated with a speed of approximately 70 rpm while being suspended stably at a gap length of 0.3 mm.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.6
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• pp.454-461
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• 2000

Electrostatic suspension offers an advantage of directly suspending various materials such as conductive materials, semiconductors and dielectric materials without any mechanical contacts. This is a specific feature compared with electromagnetic suspension which can suspend only ferro-magnetic material. In general, the electrostatic suspension systems require position sensors for stabilizing the suspended object. Therefore, a lot of displacement sensors and a switching circuit are required for moving the object through a long distance. In order to circumvent this problem, this paper proposes a self-sensing method which can provide the gap displacement between electrodes and suspended object without external sensors. Moreover a simple on-off controller is presented for stabilization. Experimental validation of the proposed scheme has been performed through the successful levitation of a 4-inch silicon wafer.

• Journal of the Korea Concrete Institute
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• v.11 no.5
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• pp.51-60
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• 1999

When placed under water, concrete is diluted with separating cementitious material and as a result the quality of concrete becomes poor. So as to solve the problem, underwater concrete is increasingly used for the construction and repair of the concrete structure under water. In this paper, 4 kinds of antiwashout admixtures and varying sand percentages were chosen to measure the suspended solids, pH, air contents, setting time and compressive strength of underwater concrete, and they meet "Standard for antiwashout admixture used for concrete". When sand percentage is 43%, the fluidity and filling of underwater concrete are superior to the others.he others.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.465-466
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• 2006

A single-wall carbon nanotube (SWCNT) has been studied as a material of Nano-Eletro-Mechanical-System (NEMS) device together with various nanowires. In order for oscillation of a multi-wall carbon nanotube (MWCNT) or a single-walled carbon nanotube (SWCNT) on plane surface, it needs suspension of a CNT across trench electrodes. So we propose fabrication method of a MWCNT resonator using dielectrophoresis and show successful results of suspeneded MWNT. Thin electrodes with large gaps could not suspend small diameter MWNT but thicker electrodes could. Thin MWNT could be suspended only when the electrode gap was reduced.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.2
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• pp.467-474
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• 2017

Each river confluence has the inherent hydraulic and mixing characteristics coming from its bathymetry and topography. It is necessary to make the measurement covering the spatial extent of studying area in order to catch these 2-dimensional intrinsic characteristics. This study focuses to investigate the hydraulic and mixing characteristics at the confluence of Nakdong and Geumho River, from field measurement of flow, water quality, and suspended particle distribution with ADCP (Riversurveyor M9), multi-parameter water quality sonde (YSI6600V2), and submersible system for in-situ observations of particle size distribution and volume concentration (LISST : Laser In-Situ Scattering & Transmissometry), respectively. From the results, it can be found that the field measurement of suspended particle and water quality distribution can be the useful approach to catch the hydraulic and mixing characteristics at a river confluence.

• Journal of Environmental Science International
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• v.5 no.2
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• pp.153-170
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• 1996

Photosynthetic pigments and their degradation products in suspended and sinking particles collected from the Gulf of Mexico waters 1987~88, were measured using High Performance liquid Chromatography (HPIC). The short term variations in flux rates of chlorophylls and carotenoids as well as-their degradation products were compared at the mesoscale cyclonic and anticyclonic circulation features (cold joie rink and warm core ring). Chlorophyll a was the predominant porphyrin of suspended particulate matter at both CCR -and WCR. Among carotenoid pigments, 19'-hexanoyloxyfucoxanthin, which is a biomarker of prymnesiophytes, was dominant pigment at both rinds. Phaeophorbide a, which is produced through the Brazing processes of grazers, was the predominant degraded pigment in sinking particles ai the study aiea. Total pigment flux in CCR was an order of magnitude higher than that in WCR. Less than l% of the standing stock of the pigments measured sank out of the upper 200m of the WCR on any given day. Thus, suspended particulate matter in Gulf of Medico was not recycled rapidly.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 2000.06a
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• pp.87-125
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• 2000

A new paradigm of crystal growth was suggested in a charged cluster model, where charged clusters of nanometer size are suspended in the gas phase in most thin film processes and are a major flux for thin film growth. The existence of these hypothetical clusters was experimentally confirmed in the diamond and silicon CVD processes as well as in gold and tungsten evaporation. These results imply new insights as to the low pressure diamond synthesis without hydrogen, epitaxial growth, selective deposition and fabrication of quantum dots, nanometer-sized powders and nanowires or nanotubes. Based on this concept, we produced such quantum dot structures of carbon, silicon, gold and tungsten. Charged clusters land preferably on conducting substrates over on insulating substrates, resulting in selective deposition. if the behavior of selective deposition is properly controlled, charged clusters can make highly anisotropic growth, leading to nanowires or nanotubes.