• Title/Summary/Keyword: Pre-treatment process

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Effect of Pre-NH3 Stripping on the Advanced Sewerage Treatment by BNR (BNR에 의한 하수의 고도처리에 미치는 NH3 스트리핑 전처리의 영향)

  • Seo, Jeong-Beom;An, Kwang-Ho
    • Journal of Korean Society on Water Environment
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    • v.22 no.5
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    • pp.846-850
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    • 2006
  • The biological nutrient removal from domestic wastewater with low C/N ratio is difficult. Therefore, this study was performed to increase influent C/N ratio by ammonia stripping without required carbon source and for improving treatment efficiencies of sewerage by the combination process of ammonia stripping and BNR (StripBNR). The results of this study were summarized as follows. BOD removal efficiencies of BNR and StripBNR were 95.3% and 93.2%, respectively. T-N and T-P removal efficiencies of BNR were 53.3% and 40.8%, respectively. T-N and T-P removal efficiencies of StripBNR were 72.8% and 62.9%, respectively. Concentrations of $NH_3-N$, $NO_2-N$ and $NO_3-N$ at BNR effluent were 0.03 mg/L, 0.08 mg/L and 9.12 mg/L, respectively. On the other hands, concentrations of $NH_3-N$, $NO_2-N$ and $NO_3-N$ at StripBNR effluent were 5.79 mg/L, 0.01 mg/L and 0.14 mg/L, respectively. Consequently, influent C/N ratio of BNR process was increased by ammonia stripping. Removal efficiency of T-N and T-P was improved about 20% by the process of StripBNR.

Wet preparation of calcium phosphates from aqueous solutions

  • Lee, Byeong Woo;Hong, Il Gok
    • Journal of Ceramic Processing Research
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    • v.20 no.6
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    • pp.655-659
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    • 2019
  • Calcium phosphates such as HA (hydroxyapatite), β-TCP (tricalcium phosphate) and biphasic HA/β-TCP, were synthesized by wet chemical precipitation in aqueous solution combined with ball milling process. Nanosize powders of the calcium phosphates were synthesized using Ca(OH)2 and H3PO4. The effects of initial precursor Ca/P ratio (1.30, 1.50 and 1.67), ball milling process and post heat-treatment on the phase evolution behavior of the powders were investigated. The phase of resulting powder was controllable by adjusting the initial Ca/P ratio. HA was the only phase for as-prepared powders in both cases of Ca/P ratios of 1.50 and 1.67. The single HA phase without any noticeable second phase was obtained for the initial Ca/P ratio of 1.67 in the overall heat-treatment range. Pure β-TCP and biphasic calcium phosphate (HA/β-TCP) were synthesized from precursor solutions having Ca/P molar ratios of 1.30 and 1.50, respectively, after having been heat-treated above 700 ℃. The β-TCP phase has appeared on the pre-existing DCPD (dicalcium phosphate dihydrate) and/or HA phase. Dense ceramics having translucency were obtained at a considerably lower sintering temperature. The modified process offered a fast, convenient and economical route for the synthesis of calcium phosphates.

Analysis of Microorganisms and Water Transport Properties of the Cotton Fabrics through Dehydration and Drying Process during Washing (세탁의 탈수와 건조과정 중 면직물의 수분전달특성 및 미생물 분석)

  • 최해운;박명자;차옥선
    • The Research Journal of the Costume Culture
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    • v.10 no.5
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    • pp.578-589
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    • 2002
  • The purpose of this research was to analyze the residual water retention and to determine the number and species of microorganisms from the wet cotton fabrics in dehydration and drying process during washing. The drying rates of terrycloth and interlock knit under the rainy seasons were measured according to the dehydration and hanging methods, layers of fabric and pre-treatment agents. Microorganisms were isolated from the dried terrycloth by pure culture, and were identified by Biolog system. The results are as follow: The initial water retention of fabrics after dehydration decreased in the order of dripping>centrifuge>squeezing method, which affected the drying rate. The drying rates were faster by increasing surface area of fabrics. There was no significant difference in drying rate among the fabrics pre-treated with detergent, or fabric softener, or cationic surfactants such as Cetyltrimethylammonium bromide(CTAB) and Benzalkonium chloride(BC). Puedomonas aureginosa was found in the fabrics treated with a powder-type detergent. On the other side, there was no growth of microorganism in the fabrics treated with a liquid-type detergent (containing antibacterial agent), CTAB and BC.

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Optimization for Electro Deposition Process of PC/ABS Resin Surface Treatment (수지의 하전 입자빔 전처리 공정의 최적화)

  • Park, Young Sik;Shim, Ha-Mong;Na, Myung Hwan;Song, Ho-Chun;Yoon, Sanghoo;Jang, Keun Sam
    • The Korean Journal of Applied Statistics
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    • v.27 no.4
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    • pp.543-552
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    • 2014
  • High bandwidth RF such as Bluetooth, GPRS, EDGE, 3GSM, HSDPA is papular in the mobile phone market. A non-conducting metal coating process requires an e-beam deposition of metal, two steps of UV hard coating primer and top coating; however, it is inefficient. We navigate to the electron beam irradiation conditions(resin surface treatment conditions) in the PC/ABS resin injection process. By analyzing the experimental results, we find the optimum development conditions for the electro deposition pre-treatment process and mass production lines using the plasma generated electron beam source.

Effect of Pre-cooking Conditions on the Quality Characteristics of Ready-To-Eat Samgyetang

  • Triyannanto, Endy;Lee, Keun Taik
    • Food Science of Animal Resources
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    • v.35 no.4
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    • pp.494-501
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    • 2015
  • The aim of this study was to examine the effectiveness of pre-cooking conditions on the quality characteristics of ready-to-eat (RTE) Samgyetang. Raw chickens were steamed under the different conditions of 50℃/30 min (T1), 65℃/30 min (T2), 85℃/30 min (T3), and 90℃/10 min (T4) prior to retorting at 120℃ for 65 min. The results showed that pre-cooking conditions in all treated samples could reduce fat contents in breast and leg meats by 8.5-11.7% and 10.0-11.0% compared to the control, even though there were no significant differences among treatments (p>0.05). The L* and b* values of breast and leg meats treated with the higher temperature and longer time conditions were significantly higher than the control (p<0.05), while a* values tended to decrease despite of not to a significant extent (p>0.05). Moreover, apparent viscosity and water soluble protein showed insignificant differences (p>0.05) among the samples as a result of the retorting process, which might have more negative influences on the quality. T2 samples obtained significantly the highest average Quantitative Descriptive Analysis (QDA) score and transmittance value, representing the most clear broth among the samples, compared to the control. On the other hand, T3 showed the highest cooking loss among the treatments and the lowest QDA scores among the samples. In conclusion, pre-cooking treatment prior to retorting in manufacturing Samgyetang is a plausible way to reduce its fat content. A pre-cooking condition at either 65℃ for 30 min, or 90℃ for 10 min are recommended for producing Samgyetang with optimum quality.

A Study on the Durability of Dimensionally Stable Electrode in High-Rate Electroplating Process Condition Using Accelerated Life Test

  • Sung Cheol Park;Yeon Jae Jung;SeokBon Koo;Kee-Ahn Lee;Seong Ho Son
    • Archives of Metallurgy and Materials
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    • v.66 no.3
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    • pp.675-678
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    • 2021
  • In order to the long-term stability of DSE for electroplating process, the lifetime equations were calculated from the results of the accelerated life testing, and the lifetime of DSE was predicted. The nano-embossing pre-treatment led to 2.65 times in the lifetime of DSE. The degradation mechanism of DSE with a thick metal oxide layer for applied highly current density process condition was identified. The improvement of durability of DSE seems to be closely related to adhesion between titanium plate and mixed metal oxide layer.

Quality characteristics and antioxidant capacities of oriental melon wine depending on pretreatments (전처리 방법에 따른 참외와인의 품질특성과 항산화능)

  • Hwang, Hee-Young;Ha, Hyoung-Tae;Ha, Se-Bi;Seong, Gi-Un;Hwang, In-Wook;Chung, Shin-Kyo
    • Food Science and Preservation
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    • v.22 no.3
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    • pp.421-427
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    • 2015
  • Oriental melon (Cucumis melo L. var. makuwa) has been widely consumed as various processed foods, such as dried products, jelly, wine, juice, and vinegar, in Asian countries. In fruit processing, blanching and pressure treatments affect its quality, such as antioxidant activities, sensory characteristics, and etc. This study was conducted to evaluate the effects of blanching and pressure pre-treatments on oriental melon wine-making (BP, blanching and pressure filtration; BNP, blanching and non-pressure filtration; NBP, non-blanching and pressure filtration; and NBNP, non-blanching and non-pressure filtration). Physicochemical properties and antioxidant capacities by ${\alpha}$, ${\alpha}$-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, ferric ion reducing antioxidant power (FRAP) assay, and total phenolic and total flavonoid contents were measured for comparison of the different pre-treatment methods. After the aging process, the alcohol contents and pH values showed no statistical differences, whereas the amount of soluble solids, reducing sugar, and titratable acidity were slightly different among the pre-treatments (p<0.05). The samples with blanching pre-treatment showed higher antioxidant capacities than those of other pre-treatments. In the sensory evaluation, the BNP was the best in overall acceptability. Thus, this study showed that the blanching treatment enhanced the antioxidant capacities and sensory qualities of the oriental melon wine.

Effects of STEAM(Science-Technology-Engineering-Art-Mathematics) Activities on Young Children's Scientific Process Skill Ability and Problem Solving Ability (STEAM(융합인재교육)활동이 유아의 과학과정기술과 문제해결력에 미치는 영향)

  • Lee, Suki;Yun, Eungyung
    • The Journal of the Korea Contents Association
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    • v.16 no.5
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    • pp.746-759
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    • 2016
  • The purpose of this study was examine the effects of STEAM(Science-Technology-Engineering-Art-mathematics) activities on young children's scientific process skill ability and problem solving ability. Subjects were 34 five-year-old young children from S and H child care centers located in G city. Subjects were divided into an experimental(n=17) and a control group(n=17). The experimental group took part in the STEAM activities during 8 weeks, while the control group took part in the traditional science activities. The procedure for this study consisted of a pre-study, a pre-test, the treatment, and a post-test schedule. The results of this study were as follows: First, the experimental group showed significantly higher score than the control group in total scientific process skill ability. Second, the experimental group showed significantly higher score than the control group in total problem solving ability. These findings suggest that the experience of STEAM activities for young children can be effective teaching-learning methods for young children's scientific process skill ability and problem solving ability.

Direct Bonding Characteristics of 2" 3C-SiC Wafers for Harsh Environment MEMS Applications (극한 환경 MEMS용 2" 3C-SiC기판의 직접접합 특성)

  • 정귀상
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.8
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    • pp.700-704
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    • 2003
  • This paper describes on characteristics of 2" 3C-SiC wafer bonding using PECVD (plasma enhanced chemical vapor deposition) oxide and HF (hydrofluoride acid) for SiCOI (SiC-on-Insulator) structures and MEMS (micro-electro-mechanical system) applications. In this work, insulator layers were formed on a heteroepitaxial 3C-SiC film grown on a Si (001) wafer by thermal wet oxidation and PECVD process, successively. The pre-bonding of two polished PECVD oxide layers made the surface activation in HF and bonded under applied pressure. The bonding characteristics were evaluated by the effect of HF concentration used in the surface treatment on the roughness of the oxide and pre-bonding strength. Hydrophilic character of the oxidized 3C-SiC film surface was investigated by ATR-FTIR (attenuated total reflection Fourier transformed infrared spectroscopy). The root-mean-square suface roughness of the oxidized SiC layers was measured by AFM (atomic force microscope). The strength of the bond was measured by tensile strength meter. The bonded interface was also analyzed by IR camera and SEM (scanning electron microscope), and there are no bubbles or cavities in the bonding interface. The bonding strength initially increases with increasing HF concentration and reaches the maximum value at 2.0 % and then decreases. These results indicate that the 3C-SiC wafer direct bonding technique will offers significant advantages in the harsh MEMS applications.ions.

Volatile Fatty Acid Production from Saccharina japonica Extracts by Anaerobic Fermentation: Evaluation of Various Environmental Parameters for VFAs Productivity (혐기성 발효에 의한 다시마 추출물로부터 휘발성 유기산 제조: 휘발성 유기산 생산성에 대한 환경적 영향인자 평가)

  • Choi, Jae Hyung;Song, Min Kyung;Chun, Byung Soo;Lee, Chul Woo;Woo, Hee Chul
    • Clean Technology
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    • v.19 no.2
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    • pp.148-155
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    • 2013
  • Volatile fatty acids (VFAs) production from marine brown algae, Saccharina japonica, was investigated in anaerobic dark fermentation. In order to evaluate the VFAs productivity, various experimental parameters (i.e., physicochemical pre-treatment, microorganism inoculation ratio, substrate concentration, and pH) were evaluated. According to the physicochemical pre-treatment methods, the maximum concentrations of VFAs were obtained in the order of sulfuric acid, subcritical water and subcritical water with lipid-extraction. Also, we investigated the operating parameters such as microorganism inoculation ratio (MV/M = 10 to 30), the substrate concentration (18.0 to 72.0 g/L) and pH (6.0 to 7.0) in sulfuric acid pre-treatment method. When the substrate concentrations were 18.0, 36.0, 54.0 and 72.0 g/L at $35^{\circ}C$, microorganism inoculation ratio 15, pH 7.0 for 372 hours, the maximum concentrations of VFAs were respectively 9.8, 13.9, 18.6 and 22.3 g/L. The change in VFAs concentrations was detected that acetic- and propionic acids increased according to increasing pH, while the butyric acid increased with decreasing pH. The VFAs obtained from concentration and separation process may be used as basic chemistry materials and bio-fuel, and they will expect to produce alternative energy of fossil fuel.