• Title/Summary/Keyword: Biological Processes

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Re-description of Sea Spider Cilunculus armatus (Pycnogonida: Ammotheidae) from Korea

  • Lee, Damin;Park, Jin-ho;Kim, Won
    • Animal Systematics, Evolution and Diversity
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    • v.36 no.4
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    • pp.330-335
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    • 2020
  • The sea spider genus Cilunculus Loman, 1908 comprises 33 species having short chelifores, separate lateral processes, and a hood structure on the cephalic segment. A pycnogonid species, Cilunculus armatus(Böhm, 1879), was collected from Baekdo Island and Chujado Island, Korea. This species is characterized by having a hood structure on the cephalic segment, separate lateral processes, a low ocular tubercle without eyes, and 3-segmented chelifores. In the examined material, chela shape, arrangement of compound spines on strigilis, and number of heel spines at propodus were different from the previous literatures. Here, we examined C. armatus collected in Korean waters and provided illustrations and pictures in detail.

Modeling, Control, and Optimization of Activated Sludge Processes

  • Bae, Hye-on;Kim, Bong-chul;Kim, Sung-shin;Kim, Chang-won;Kim, Sang-hyun
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.1 no.1
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    • pp.56-61
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    • 2001
  • Activated sludge processes are broadly used in the biological wastewater treatment processes. The activated sludge processes are complex systems because of the many factors such as the variation of influent flowrate and ingredients, the complexity of biological reactions, and the various operation conditions. The main motivation o this research is to develop an intelligent control strategy for activated sludge process (ASP). ASP is a complex and nonlinear dynamic system owing to the characteristic of wastewater, the change in influent flowrate, weather conditions, and so on. The mathematical model of ASP also includes the uncertainty which is a ignored or unconsidered factor from process designers. The ASP model based on Matlabⓡ/Simulinkⓡ is developed in this paper. And the model performance is examined by IWA (International Water Association) and COST (European Cooperation in the filed of Scientific and Technical Research) data. The model tests derive steady-state results of 14 days. In this paper, fuzzy logic control approach is applied to handle DO concentrations. The fuzzy logic controller includes two inputs and one output to adjust air flowrate. The objective function for the optimization, in the implemented evolutionary strategy, is formed with focusing on improving the effluent quality and reducing the operating cost.

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In-situ Warpage Measurement Technique Using Impedance Variation (임피던스 변화를 이용한 실시간 기판 변형 측정)

  • Kim, Woo Jae;Shin, Gi Won;Kwon, Hee Tae;On, Bum Soo;Park, Yeon Su;Kim, Ji Hwan;Bang, In Young;Kwon, Gi-Chung
    • Journal of the Semiconductor & Display Technology
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    • v.20 no.1
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    • pp.32-36
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    • 2021
  • The number of processes in the manufacture of semiconductors, displays and solar cells is increasing. And as the processes is performed, multiple layers of films and various patterns are formed on the wafer. At this time, substrate warpage occurs due to the difference in stress between each film and pattern formed on the wafer. the substrate warping phenomenon occurs due to the difference in stress between each film and pattern formed on the wafer. We developed a new warpage measurement method to measure wafer warpage during real-time processing. We performed an experiment to measure the presence and degree of warpage of the substrate in real time during the process by adding only measurement equipment for applying additional electrical signals to the existing ESC and detecting the change of the additional electric signal. The additional electrical measurement signal applied at this time is very small compared to the direct current (DC) power applied to the electrostatic chuck whit a frequency that is not generally used in the process can be selectively used. It was confirmed that the measurement of substrate warpage can be easily separated from other power sources without affecting.

Shikimate Metabolic Pathway Engineering in Corynebacterium glutamicum

  • Park, Eunhwi;Kim, Hye-Jin;Seo, Seung-Yeul;Lee, Han-Na;Choi, Si-Sun;Lee, Sang Joung;Kim, Eung-Soo
    • Journal of Microbiology and Biotechnology
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    • v.31 no.9
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    • pp.1305-1310
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    • 2021
  • Shikimate is a key high-demand metabolite for synthesizing valuable antiviral drugs, such as the anti-influenza drug, oseltamivir (Tamiflu). Microbial-based strategies for shikimate production have been developed to overcome the unstable and expensive supply of shikimate derived from traditional plant extraction processes. In this study, a microbial cell factory using Corynebacterium glutamicum was designed to overproduce shikimate in a fed-batch culture system. First, the shikimate kinase gene (aroK) responsible for converting shikimate to the next step was disrupted to facilitate the accumulation of shikimate. Several genes encoding the shikimate bypass route, such as dehydroshikimate dehydratase (QsuB), pyruvate kinase (Pyk1), and quinate/shikimate dehydrogenase (QsuD), were disrupted sequentially. An artificial operon containing several shikimate pathway genes, including aroE, aroB, aroF, and aroG were overexpressed to maximize the glucose uptake and intermediate flux. The rationally designed shikimate-overproducing C. glutamicum strain grown in an optimized medium produced approximately 37.3 g/l of shikimate in 7-L fed-batch fermentation. Overall, rational cell factory design and culture process optimization for the microbial-based production of shikimate will play a key role in complementing traditional plant-derived shikimate production processes.

Advanced oxidation technologies for the treatment of nonbiodegradable industrial wastewater (난분해성 산업폐수 처리를 위한 고도산화기술)

  • Kim, Min Sik;Lee, Ki-Myeong;Lee, Changha
    • Journal of Korean Society of Water and Wastewater
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    • v.34 no.6
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    • pp.445-462
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    • 2020
  • Industrial wastewater often contains a number of recalcitrant organic contaminants. These contaminants are hardly degradable by biological wastewater treatment processes, which requires a more powerful treatment method based on chemical oxidation. Advanced oxidation technology (AOT) has been extensively studied for the treatment of nonbiodegradable organics in water and wastewater. Among different AOTs developed up to date, ozonation and the Fenton process are the representative technologies that widely used in the field. Based on the traditional ozonation and the Fenton process, several modified processes have been also developed to accelerate the production of reactive radicals. This article reviews the chemistry of ozonation and the Fenton process as well as the cases of application of these two AOTs to industrial wastewater treatment. In addition, research needs to improve the cost efficiency of ozonation and the Fenton process were discussed.

Effect of Hydraulic Pressure on Organic Fouling in Pressure Retarded Osmosis (PRO) Process (압력지연삼투 (PRO) 공정에서 유도용액에서의 압력이 유기물 파울링에 미치는 영향)

  • Suh, Dongwoo;Yoon, Hongsik;Yoon, Jeyong
    • Journal of Korean Society of Water and Wastewater
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    • v.29 no.1
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    • pp.133-138
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    • 2015
  • Pressure retarded osmosis (PRO) process is one of membrane processes for harvesting renewable energy by using salinity difference between feed and draw solutions. Power is generated by permeation flux multiplied by hydraulic pressure in draw side. Membrane fouling phenomena in PRO process is presumed to be less sever, but it is inevitable. Membrane fouling in PRO process decreases water permeation through membrane, resulting in significant power production decline. This study intended to investigate the effect of hydraulic pressure in PRO process on alginate induced organic fouling as high and low hydraulic pressures (6.5 bar and 12 bar) were applied for 24 h under the same initial water flux. In addition, organic fouling in draw side from the presence of foulant (sodium alginate) in draw solution was examined. As major results, hydraulic pressure was found to be not a significant factor affecting in PRO organic fouling as long as the same initial water flux is maintained, inidicating that operating PRO process with high hydraulic pressure for efficient energy harvesting will not cause severe organic fouling. In addition, flux decline was negligible from the presence of organic foulant in draw side.

Fate and mass balance of pharmaceuticals of unit processes in a sewage treatment plant (하수처리시설 단위공정별 잔류의약물질 거동 및 물질수지 분석)

  • Park, Junwon;Kim, Changsoo;Lee, Wonseok;Lee, Soo-Hyung;Chung, Hyenmi;Jeong, Dong-Hwan
    • Journal of Korean Society of Water and Wastewater
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    • v.33 no.5
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    • pp.367-377
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    • 2019
  • In this study, the fate and removal of 15 pharmaceuticals (including stimulants, non-steroidal anti-inflammatory drugs, antibiotics, etc.) in unit processes of a sewage treatment plant (STP) were investigated. Mass loads of pharmaceuticals were 2,598 g/d in the influent, 2,745 g/d in the primary effluent, 143 g/d in the secondary effluent, and 134 g/d in the effluent. The mass loads were reduced by 95% in the biological treatment process, but total phosphorous treatment did not show a significant effect on the removal of most pharmaceuticals. Also, mass balance analysis was performed to evaluate removal characteristics of pharmaceuticals in the biological treatment process. Acetaminophen, caffeine, acetylsalicylic acid, cefradine, and naproxen were efficiently removed in the biological treatment process mainly due to biodegradation. Removal efficiencies of gemfibrozil, ofloxacin, and ciprofloxacin were not high, but their removal was related to sorption onto sludge. This study provides useful information on understanding removal characteristics of pharmaceuticals in unit processes in the STP.