• Title/Summary/Keyword: Process temp

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Optimization of Supercritical Water Oxidation(SCWO) Process for Decomposing Nitromethane (Nitromethane 분해를 위한 초임계수 산화(SCWO) 공정 최적화)

  • Han, Joo Hee;Jeong, Chang Mo;Do, Seung Hoe;Han, Kee Do;Sin, Yeong Ho
    • Korean Chemical Engineering Research
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    • v.44 no.6
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    • pp.659-668
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    • 2006
  • The optimization of supercritical water oxidation (SCWO) process for decomposing nitromethane was studied by means of a design of experiments. The optimum operating region for the SCWO process to minimize COD and T-N of treated water was obtained in a lab scale unit. The authors had compared the results from a SCWO pilot plant with those from a lab scale system to explore the problems of scale-up of SCWO process. The COD and T-N in treated waters were selected as key process output variables (KPOV) for optimization, and the reaction temperature (Temp) and the mole ratio of nitromethane to ammonium hydroxide (NAR) were selected as key process input variables (KPIV) through the preliminary tests. The central composite design as a statistical design of experiments was applied to the optimization, and the experimental results were analyzed by means of the response surface method. From the main effects analysis, it was declared that COD of treated water steeply decreased with increasing Temp but slightly decreased with an increase in NAR, and T-N decreased with increasing both Temp and NAR. At lower Temp as $420{\sim}430^{\circ}C$, the T-N steeply decreased with an increase in NAR, however its variation was negligible at higher Temp above $450^{\circ}C$. The regression equations for COD and T-N were obtained as quadratic models with coded Temp and NAR, and they were confirmed with coefficient of determination ($r^2$) and normality of standardized residuals. The optimum operating region was defined as Temp $450-460^{\circ}C$ and NAR 1.03-1.08 by the intersection area of COD < 2 mg/L and T-N < 40 mg/L with regression equations and considering corrosion prevention. To confirm the optimization results and investigate the scale-up problems of SCWO process, the nitromethane was decomposed in a pilot plant. The experimental results from a SCWO pilot plant were compared with regression equations of COD and T-N, respectively. The results of COD and T-N from a pilot plant could be predicted well with regression equations which were derived in a lab scale SCWO system, although the errors of pilot plant data were larger than lab ones. The predictabilities were confirmed by the parity plots and the normality analyses of standardized residuals.

The Effect of Heat Treatment Temperature on the Dimension and Handle of PET/PBT Fabric (가공공정 중 열처리 온도에 의한 PET/PBT 혼섬사 직물의 형태와 태의 변화)

  • 신혜원
    • Journal of the Korean Society of Clothing and Textiles
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    • v.27 no.5
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    • pp.582-587
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    • 2003
  • To examine the effect of heat treatment temperature in finishing process on PET/PBT Fabric, PET/PBT Fabrics were treated at different relaxing temp., pre-set temp., and final-set temp.. The dimensions such as thickness and density were measured, and the handles were evaluated by Kawabata system. In relaxing which was wet heat treatment, thickness and bulkiness were increased, and NUMERI, FUKURAMI, SOFUTOSA, and THV also were increased but KOSHI was decreased with elevating temperature. With elevating pre-set temp., thickness and bulkiness were decreased, but KOSHI was increased. NUMERI, FUKURAMI, SOFUTOSA, and THV were the best at 180$^{\circ}C$ pre-set treatment. In final-set which was dry heat treatment like pre-set, thickness, bulkiness, NUMERI, HUKURAMI, SOFUTOSA, and THV were decreased, but KOSHI value was increased with elevating temperature. Therefore the best heat treatment condition was 130$^{\circ}C$ relaxing, 180$^{\circ}C$ pre-set, and 160$^{\circ}C$ final-set. And the handle of PET/PBT Fabric was affected much more by relaxing temp. than pre-set temp. and final-set temp.

Effect of TempCore Processing on Microstructure and Mechanical Properties of 700 MPa-Grade High-Strength Seismic Resistant Reinforced Steel Bars (700 MPa급 고강도 내진 철근의 미세조직과 기계적 특성에 미치는 템프코어 공정의 영향)

  • Shin, S.H.;Kim, S.K.;Lim, H.G.;Hwang, B.
    • Transactions of Materials Processing
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    • v.30 no.2
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    • pp.91-98
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    • 2021
  • The present study deals with the microstructure and mechanical properties of 700 MPa-grade high-strength seismic resistant reinforced steel bars fabricated by various TempCore process conditions. For the steel bars, in the surface region tempered martensite was formed by water cooling and subsequent self-tempering during TempCore process, while in the center region there was ferrite-pearlite or bainite microstructure. The steel bar fabricated by the highest water flow and the lowest equalizing temperature had the highest hardness in all regions due to the relatively fine microstructure of tempered martensite and bainite. In addition, the steel bar having finer microstructures as well as the high fraction of tempered martensite in the surface region showed the highest yield and tensile strengths. The presence of vanadium precipitates and the high fraction of ferrite contributed to the improvement of seismic resistance such as high tensile-to-yield strength ratio and high uniform elongation.

Fabrication and Characteristics of ZnO TFTs for Flexible Display using Low Temp Process (Flexible Display용 Low Temp Process를 이용한 ZnO TFT의 제작 및 특성 평가)

  • Kim, Young-Su;Kang, Min-Ho;Nam, Dong-Ho;Choi, Kang-Il;Oh, Jae-Sub;Song, Myung-Ho;Lee, Hi-Deok;Lee, Ga-Won
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.44-44
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    • 2009
  • Recently, transparent ZnO-based TFTs have attracted much attention for flexible displays because they can be fabricated on plastic substrates at low temperature. We report the fabrication and characteristics of ZnO channel layers(ZnO TFTs) having different channel thicknesses. The ZnO film were deposited as active channel layers on $Si_3N_4/Ti/SiO_2p$-Si substrates by rf magnetron sputtering at $100\;^{\circ}C$ without additional annealing. Also the Zno thin films deposited at oxygen partial pressures of 40%. ZnO TFTs using a bottom-gate configuration were investigated. The $Si_3N_4$ film were deposited as gate insulator by PE-CVD at $15\;^{\circ}C$. All Processes were processed below $150^{\circ}C$ which is optimal temperature for flexible display and were used dry etching method.

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Development of the formulation and the process of DXD-19 sheet explosive (판상 화약 DXD-19 조성 및 성형 공정개발)

  • Cheun Young Gu;Lee Jin Sung
    • Journal of the Korea Institute of Military Science and Technology
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    • v.7 no.3 s.18
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    • pp.129-139
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    • 2004
  • DXD-19 is a flexible sheet explosive, which is a new polymer-bonded explosives(PBX's). DXD-19 is relatively insensitive and can be extruded into various configurations to be applied to munitions. A typical application includes multi-point initiation for the warhead, cutting/severance devices and transfer lines. The DXD-19 composition employs a binder system derived from the thermoplastic elastomer(HyTemp 4454) containing $5\%$ OH terminated with isocyanate curable for increasing mechanical properties. The use of an elastomer CAB increases its mechanical properties and the use of an energetic plasticizer BDNPF/BDNPA(F/A) improves the process ability as well as energy contents. The composition of the extruded DXD-19 formulation is formed $\%$ weight of $PETN/HyTemp/ATEC/(F/A)/CAB=72\~73/12\~13/6\~7/6\~7/1\~2$. Our safety tests of DXD-19 shows Insensitivity to an impact test and friction test, good thermal stability and excellent mechanical properties.

A study on the Durable Press finish by Wet-Fixation Process for Rayon Fabrics (II) - Effect of Treatment Temperature and Time - (레이온 직물의 Wet-Fixation에 의한 DP가공에 관한 연구(II) -처리온도 및 시간의 영향-)

  • Hu Yoon Sook;Kim Eun Ae
    • Journal of the Korean Society of Clothing and Textiles
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    • v.13 no.4
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    • pp.357-369
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    • 1989
  • The purpose of this study was to investigate the effects of treatment temperature and time on the, of easy-care and strength properties of the wet fixation processed rayon fabrics. Viscose rayon fabrics were treated with mixed resins of melamine formaldehyde (MF) and DMDHEU by one bath and two bath wet fixation processes. The MF/DMDHEU mixed resin concentrations were 50/100, 50/150, 100/100 and 100/150(g/1). Magnasium chloride was used as a catalyst. The wet fixation conditions were 24hrs at room temperature,20 mins at $75^{\circ}C$ and 5 mins at $105^{\circ}C$ Wet fixation processed fabrics did not show the difference in the resin add-one, DP ratings and wrinkle recovery angles by the different treatment temperatures and times. DP ratings were in the order of $105^{\circ}C>75^{\circ}C>room$ temp, in one bath and two bath wet fixation. Breaking and tearing strength of one bath processed fabrics showed in the order of $75^{\circ}C>room\;temp>105^{\circ}C$ The breaking strength of two bath processed fabrics showed in the order of $105^{\circ}C>75^{\circ}C>room$ temp. Tearing strength showed in the order of $75^{\circ}c>105^{\circ}C>room$ temp. Abrasion resistances were in the order of $75^{\circ}C>105^{\circ}C>room$ temp. in one bath and two bath processes.

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Evaluation and Comparison with Standard 48 hr Acute Bioassay and High Temperature Rapid Toxicity Test for Sewage Toxicity Test (하수의 독성평가를 위한 표준독성시험법과 온도증가 단기독성평가법의 비교 평가)

  • Lee, Sang-Ill;Jun, Byong-Hee;Weon, Seung-Yeon;Kim, Yi-Jung;Kim, Keum-Yong
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.2
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    • pp.191-197
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    • 2005
  • A new method, ToxTemp (TOXcity test based on TEMPerature control) using Ceridaphnia dubia was applied to evaluate the toxicity of insecticide materials and compared with the standard 48 hr acute bioassay. BPMC, diazinon and fenitrothion may cause the inhibition to the biological process in sewage treatment plant and need to detect toxicity within short contact time. The ToxTemp method showed sensitive detection with more shorter contact of 1-1.5 hr time than that of the standard 48 hr acute bioassay. To evaluate toxicity of real wastewater/sewage, the inhibition rate of nitrification and oxygen uptake rate (OUR) using activated sludge, the standard 48hr acute bioassay and ToxTemp method using C. dubia were compared, respectively. On the basis of the inhibition rate of nitrification, the OUR test showed the less sensitive results at the relatively strong toxic sewage. On the other hands, the standard 48hr acute bioassay and ToxTemp method using C. dubia represented the toxicity of each wastewater/sewage with high sensitivity. Even the slightly low (about 1.5%) sensitivity, the ToxTemp method showed the high applicability to the real site of sewage treatment plant.

ADP DRY ETCHER TECHNOLOGY (ADP Dry Etcher 장비개발의 현황)

  • Kim, Jeong-Tae
    • Proceedings of the Korean Society Of Semiconductor Equipment Technology
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    • 2008.05a
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    • pp.23-29
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    • 2008
  • - High Density Plasma Source-CCP-Dual/Triple, RF Frequency Control - Radical/Flux Analysis - Low Pressure Process - Chamber Design (Process gap/Wall gap) - Chamber Temp. Control. - ESC Dielectric Materials - Uniform Gas Injection

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The Analysis of NBOD from Sewer Outflow in Winter Season by the COD Fractions using the Respirometry and Process Simulations (미생물호흡률 측정에 의한 COD분액과 공정모사를 이용한 동절기 하수유출수의 NBOD 발생원인 분석)

  • Cho, Wook Sang;Kang, Seong Wook;Im, Dong Hyuk
    • Journal of Korean Society on Water Environment
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    • v.26 no.1
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    • pp.96-103
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    • 2010
  • In this work, the presence of nitrification biochemical oxygen demand (NBOD) frequently occurred in the sewer outflow in winter season was analysed by the COD fraction methods using the respirometry and process simulations with real operation data measurements and analysis. The activated sludge models applied in this process simulation were based on the ASM No.2d temp. models, published by International Association on Water Quality (IAWQ). The ASM No.2d model is an extension of the ASM No.2 model and takes into account of carbon removal, nitrification, denitrification and phosphorus removal. The denitrifying capacity of phosphorus accumulating organisms has been implemented in the ASM No.2d model because experimental evidence shows that some of the phosphorus accumulating organisms can denitrify. It was shown that the concentrations of autotrophs (X_AUT) in the secondary clarifier and the $NH_4-N$ of T-N increased in the presence of NBOD measurements. Because of the low temperature (average $8^{\circ}C$) and possible operational troubles, the outcoming autotrophs exhausted oxygen in the process of nitrifying $NH_4-N$.

Comparison of fracture strength after thermomechanical aging between provisional crowns made with CAD/CAM and conventional method

  • Reeponmaha, Tanapon;Angwaravong, Onauma;Angwarawong, Thidarat
    • The Journal of Advanced Prosthodontics
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    • v.12 no.4
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    • pp.218-224
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    • 2020
  • PURPOSE. The objectives of this study were to evaluate the fracture strength and fracture patterns of provisional crowns fabricated from different materials and techniques after receiving stress from a simulated oral condition. MATERIALS AND METHODS. A monomethacrylate-based resin (Unifast Trad) and a bis-acryl-based (Protemp 4) resin were used to fabricate provisional crowns using conventional direct technique. A milled monomethacrylate resin (Brylic Solid) and a 3D-printed bis-acrylate resin (Freeprint Temp) were chosen to fabricate provisional crowns using the CAD/CAM process. All cemented provisional crowns (n=10/group) were subjected to thermal cycling (5,000 cycles at 5°-55℃) and cyclic occlusal load (100 N at 4 Hz for 100,000 cycles). Maximum force at fracture was tested using a universal testing machine. RESULTS. Maximum force at fracture (mean ± SD, N) of each group was 657.87 ± 82.84 for Unifast Trad, 1125.94 ± 168.07 for Protemp4, 953.60 ± 58.88 for Brylic Solid, and 1004.19 ± 122.18 for Freeprint Temp. One-way ANOVA with Tamhane post hoc test showed that the fracture strength of Unifast Trad was statistically significantly lower than others (P<.01). No statistically significant difference was noted among other groups. For failure pattern analysis, Unifast Trad and Brylic Solid showed less damage than Protemp 4 and Freeprint Temp groups. CONCLUSION. Provisional crowns fabricated using the CAD/CAM process and the conventionally fabricated bis-acryl resins exhibited significant higher fracture strength compared to conventionally fabricated monomethacrylate resins after the aging regimen. Therefore, CAD/CAM milling and 3D printing of provisional restorations may be good alternatives for long term provisionalization.