• Title/Summary/Keyword: 스테인레스

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The Physical Properties of Mn-Ferrite According to the Variation of Fe-Mn Composition Ratio (철-망간 화합비 변화에 따르는 망간 페라이트의 물성)

  • Kim, Yu-Sang;Hwang, Yong-Gil
    • Korean Journal of Materials Research
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    • v.2 no.2
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    • pp.126-132
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    • 1992
  • Experiment has been performed to investigate the thermal and magnetic properties of Mn-ferrite by electrolysis. Using the 0.2%C mild steel as soluble anode and SUS 304 stainless steel as cathode, Mn-ferrite could be made from the sulfuric acid leaching of the wasted manganese dry cell and $MnSO_4$reagent by electrolysis. As the result of X-ray diffraction, thermal analysis and magnetic measurement, Mn-ferrite was the spinel type in $Mn_{x}Fe_{3-x}O_4$ (X=1), the weight loss rate of $Mn_{x}Fe_{3-x}O_4$ were linearly increased up to the $200^{\circ}C$. Ms, Mr and Hc values were decreased with increasing Mn content and heating temperature. When Mn-ferrite was formed by $MnCl_2$reagent electrolysis, Ms values were higher than those formed from the sulfuric acid leaching of the wasted manganese dry cell and $MnSO_4$reagent by electrolysis. In Mn-ferrite, which was formed from the sulfuric acid leaching of the wasted manganese dry cell by electrolysis, Ms and Mr values were higher, Hc values were lower than which was formed by $MnSO_4$ reagent electrolysis at $200^{\circ}C\;and\;300^{\circ}C, while the same values at $100^{\circ}C$. The shape of particles was spherical type, the sizes of them were about $0.1{\mu}m$ sub-micron in $MnSO_4$reagent electrolysis, $0.5{\mu}m$ in the sulfuric acid leaching of the wasted manganese dry cell by electrolysis.

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Measurements of Streambed Hydraulic Conductivity Using Drive-point Piezometers and Seepage Meters in the Upper Reaches of Anseong Stream (관입형 피조미터와 시피지미터를 이용한 안성천 상류구간 하상 수리전도도 측정)

  • Lee, Jeongwoo;Chun, Seon Geum;Yi, Myeong Jae;Kim, Nam Won;Chung, Il-Moon;Lee, Min Ho
    • The Journal of Engineering Geology
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    • v.25 no.3
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    • pp.413-420
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    • 2015
  • Streambed hydraulic conductivity along the upper reaches of the Gongdo stage of Anseong Stream was estimated through measurements of stream-aquifer exchange rates (using a seepage meter) and vertical hydraulic gradients (using a manually driven piezometer). From the measured data, it was found out that the stream-aquifer exchange rates varied from -1.55 × 10-6 to 1.77 × 10-5 m/s, the corresponding vertical hydraulic gradient varied from -0.122 to 0.030, and the values of the streambed vertical hydraulic conductivity were estimated from 1.77 × 10-5 to 1.97 × 10-3 m/s, with variations representing local differences. The results are within the general range of streambed hydraulic conductivity values suggested by Calver (2001) and are slightly higher than values previously measured at other stream sites in Korea. The combined use of a drive-point piezometer and seepage meter (both constructed of high-strength stainless steel) is expected to be of practical use in the estimation of streambed hydraulic conductance, given the durability and portability of the instruments.

Quality Characteristics of Distilled Liquor Produced Using Ipguk (Koji) During Aging (입국으로 제조한 증류주의 숙성에 따른 품질 특성)

  • Lee, Dae-Hyoung;Jung, Jae-Woon;Lee, Yong-Seon;Seo, Jae-Soon;Park, In-Tae;Kim, Tae-Wan;Kim, Jae-Ho;Ahn, Byung-Hak
    • Korean Journal of Food Science and Technology
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    • v.46 no.6
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    • pp.694-701
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    • 2014
  • This study aimed to investigate the aging of liquor brewed with fermented wine using ipguk (koji) in a jar (JA) and stainless steel container (SC), which are generally used in Korea, and to review the characteristics of the liquors as a function of aging time. The initial alcohol content was 39.8-40.9%, and gradually decreased in the JA and SC as the aging time increased. In the case of fusel alcohols, the n-propanol, isobutanol, and isoamyl alcohol contents did not increase with increasing aging time, in the cases of both JA and SC. The A/B (isoamyl alcohol/isobutyl alcohol) ratio was similar under reduced pressure (RP) and atmospheric pressure (AP), at 1.32-135. The A/P (isoamyl alcohol/n-propanol) and B/P (isobutyl alcohol/n-propanol) ratios were 2.17-2.22 and 1.62-1.68, respectively. During the early stages of distillation, under RP, the isoamyl alcohol content was the greatest, followed by isobutyl alcohol and ethyl palmitate. Under AP, the isoamyl alcohol content was the greatest followed by decanoic acid, ethyl palmitate, and isobutyl alcohol. The highest sensory score under RP, 60 cmHg, was $6.98{\pm}0.28$.

STRESS DISTRIBUTION OF ENDODONTICALLY TREATED MAXILLARY SECOND PREMOLARS RESTORED WITH DIFFERENT METHODS: THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS (상이한 방법으로 수복한 근관치료된 상악 제2소구치의 응력분포: 3차원 유한요소법적 분석)

  • Lim, Dong-Yeol;Kim, Hyeon-Cheol;Hur, Bock;Kim, Kwang-Hoon;Son, Kwon;Park, Jeong-Kil
    • Restorative Dentistry and Endodontics
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    • v.34 no.1
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    • pp.69-79
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    • 2009
  • The purpose of this study was to evaluate the influence of elastic modulus of restorative materials and the number of interfaces of post and core systems on the stress distribution of three differently restored endodontically treated maxillary second premolars using 3D FE analysis. Model 1, 2 was restored with a stainless steel or glass fiber post and direct composite resin. A PFG or a sintered alumina crown was considered. Model 3 was restored by EndoCrown. An oblique 500 N was applied on the buccal (Load A) and palatal (Load B) cusp. The von Mises stresses in the coronal and root structure of each model were analyzed using ANSYS. The elastic modulus of the definitive restorations rather than the type of post and core system was the primary factor that influenced the stress distribution of endodontically treated maxillary premolars. The stress concentration at the coronal structure could be lowered through the use of definitive restoration of high elastic modulus. The stress concentration at the root structure could be lowered through the use of definitive restoration of low elastic modulus.

A Study on Intermediate Layer for Palladium-Based Alloy Composite Membrane Fabrication (팔라듐 합금 복합막 제조를 위한 Intermediate Layer 연구)

  • Hwang, Yong-Mook;Kim, Kwang-Je;So, Won-Wook;Moon, Sang-Jin;Lee, Kwan-Young
    • Applied Chemistry for Engineering
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    • v.17 no.5
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    • pp.458-464
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    • 2006
  • The Pd-Ni-Ag alloy composite membrane using modified porous stainless steel (PSS) as a substrate was prepared by a electroless plating technique. In this work, we have introduced the intermediate layer between Pd-based alloy and a metal substrate. As an intermediate layer, the mixtures of nickel powder and inorganic sol such as $SiO_{2}$ sol, $Al_{2}O_{3}$ sol, and $TiO_{2}$ sol were used. The intermediate layers were coated onto a PSS substrate according to various membrane preparation conditions and then $N_{2}$ fluxes through the membranes with different intermediate layers were measured. The surface morphology of the intermediate layer in the mixture of nickel powder and inorganic sol was analyzed using scanning electron microscope (SEM). Finally, the Pd-Ni-Ag alloy composite membrane using the support coated with the mixture of nickel powder and silica as an intermediate layer was fabricated and then the gas permeances for $H_{2}$ and $N_{2}$ through the Pd-based membrane were investigated. The selectivity of $H_2/N_2$ was infinite and the $H_{2}$ flux was $1.39{\times}10^{-2}mol/m^2{\cdot}s$ at the temperature of $500^{\circ}C$ and trans-membrane pressure difference of 1 bar.

Development of the New Austenitic Stainless Steels by Controlling Primary Solidification Mode (초정응고 형식 제어에 의한 오스테나이트계 스테인리스 신강종의 개발)

  • 정호신
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.27 no.2
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    • pp.132-140
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    • 1991
  • The aim of this study was saving of chromium and nickel content in the austenitic stainless steels, SUS 316 and SUS 321. By control of primary solidification mode, new austenitic stainless steels with good weldability, high toughness and corrosion resistance could be developed. The main results obtained were as follows; 1. Hot crack resistance of laboratory melts was good and higher than imported austenitic stainless steel. 2. Cryogenic and room temperature toughness of laboratory melts were high and laboratory melts M-7 to M-9 showed very high toughness than SUS321 imported stainless steel. 3. Intergranular corrosion resistance of laboratory melts was higher than imported stainless steels, SUS316 and SUS321. 4. By this concept of controlling primary solidification mode, could save expensive alloy additives, chromium and nickel.

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Comparison of Aluminum Leaching from Cooking Utensils During Cooking (조리시 조리용기로 부터의 알루미늄 용출량 비교)

  • Kim, Joong-Man;Han, Sung-Hee;Baek, Seung-Hwa
    • Korean Journal of Food Science and Technology
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    • v.29 no.4
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    • pp.613-617
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    • 1997
  • This study was performed to investigate the effects of the type of utensils (onggi, aluminum, enamel coated, stainless-steel and stone), cooking sources (deionized-water, doenjang soup and kochujang soup), and cooking time (0, 10, 20, and 30 min) on aluminum leaching. Aluminum content leached by onggi, aluminum, enamel coated, stainless-steel and stone was $0.53{\sim}2.76,\;1.17{\sim}4.20,\;0.77{\sim}3.23,\;0.53{\sim}2.03,\;0.83{\sim}2.70$ ppm in deionized-water, respectively; $4.60{\sim}7.73,\;6.45{\sim}11.50,\;5.53{\sim}9.27,\;3.50{\sim}6.70,\;5.00{\sim}9.13$ ppm in doenjang soup, respectively; $5.18{\sim}9.70,\;6.30{\sim}11.23,\;4.73{\sim}8.63,\;3.23{\sim}6.50,\;4.50{\sim}9.25$ ppm in kochujang soup, respectively. The leached aluminum content was increased with the elapse of cooking time. Aluminum utensil showed the highest leached aluminum content among different types of utensils.

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Characteristic and Adhesive Strength Change by Heat Treatment of the Plasma Sprayed $ZrO_{2}$- Thermal Barrier Coatings(TBC) (플라즈마 용사된 $ZrO_{2}$-단열 코팅층의 특성 및 열처리에 따른 접합강도변화)

  • Kim, Byoung-Hee;Suhr, Dong-Soo
    • Korean Journal of Materials Research
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    • v.8 no.6
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    • pp.505-512
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    • 1998
  • In this study, two-layer thermal barrier coatings composed of plasma sprayed 0.3mm $ZrO_2(8wt% Y_2o_3)$ ceramic coating layer and O.lmm $NiCrAlCoY_20_3$ bond coating layer on AISI 316 were investigated microstructure of the coating, oxidation of the metallic bond coating and adhesive strength to evaluate the durability of coating layer after cyclic and isothermal test at 90$0^{\circ}C$. And quantitative phase analysis of $ZrO_2(8wt% Y_2o_3)$ ceramic coating was performed as a function of thermal exposure time using XRD technique. The results showed that the amount of m - 2rO, phase in the coating was slightly increased with increasing thermal exposure time at 90$0^{\circ}C$. The c/a ratio of t' - $ZrO_2$ in the as-sprayed coating was 1.0099 and slightly increased to 1.0115 after 100 hours heat treatment. It was believed that $Y_2O_3$ in high yttria tetragonaJ(t') was transformed to low yttria tetragonaJ(t) by $Y_2O_3$ diffusion with increasing thermal exposure time. The adhesive strength was gradually decreased as thermal exposure time increased. After the isothermal test, the failure predominantly occured in ceramic coating layer. On the other hand. the specimens after cyclic thermal test were mostly failed at bond coating/ceramic coating interface. The failure was oeeured by decreasing the bond strength between bond coating and oxide scale which were formed by oxidation of the metallic elements within bond coating and by thermal stress due to thermal expansion mismatches between the oxide scale and ceramic coating.

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Toxicological effects of pesticides on loach in rice paddy (벼 재배 논 서식 미꾸리에 대한 농약의 영향)

  • Park, Yeon-Ki;Park, Kyeong-Hoon;Joo, Jin-Bok;Kyung, Kee-Sung;Kim, Byung-Seok;Shin, Jin-Sup;Ryu, Gap-Hee;Bae, Chul-Han;Lee, Kyu-Seung
    • The Korean Journal of Pesticide Science
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    • v.7 no.2
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    • pp.131-138
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    • 2003
  • A toxicological study of the pesticides for rice paddy to loach was conducted with iprobenfos 17% GR, diazinon 3 % GR, and butachlor 5 % GR to establish the field test method and their toxicological effects on loach under the actual field conditions. The type C of cage was more effective in the sense of a little stress from the cage. The nets for shading and for preventing the birds were necessary to maintain the water temperature and to prevent the predators. The cumulative mortality of loach exposed to iprobenfos 17% GR, diazinon 3% GR and butachlor 5% GR were 10, 55 and 22%, respectively, during 7 days of exposure. The averaged concentration of the pesticides in paddy water 2 days after application were 1.67, 0.22 and 0.26 mg/L, and mortalities were 7, 50 and 17%, respectively, representing the similar results with acute toxicity $(48h-LC_{50})$.

A Pilot Study for Microfiltration of Alcohol Stillage Condensate and Permeate Recycle to Fermentation Broth (알코홀 증류폐액의 Pilot Scale 정밀여과와 여과액의 발효 재활용에 대한 연구)

  • 김영범;이기세;남궁견;김종현
    • KSBB Journal
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    • v.16 no.4
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    • pp.403-408
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    • 2001
  • Distillation condensate generated from downstream processing of microbial alcohol fermentation imposes a serious burden to biological wastewater treatment or anaerobic digestion due to its high contents of SS (suspended solids) and TN (total nitrogen), A pilot scale microfiltration of the stillage condensate with a stainless steel SCEPTER membrane of 0.1 ${\mu}$m pore size was carried out to remove SS which was mostly composed of microbial cell residue. A stable permeate flux was achieved when the decanter effluent containing 0.7% of SS was filtered under the conditions of X10 VCR (volume concentration ratio), 2.5 bar of TMP (transmembrane pressure), and 60$^{\circ}C$. When stillage condensate with 2.6% SS was treated directly with microfiltration, VCR below X3 was recommended for a long duration of filtration. The permeate and retentate obtained from microfiltration were recycled to make-up medium of fermentation. Adding permeate or retentate up to 30% of fermentation volume showed no distinguished undesirable influence during the course of alcohol fermentation. Although only slight improvements in the final amount of CO$_2$ evolution and alcohol content were observed, fermentation rate increased so that the required time to reach 450 L/ton of CO$_2$ evolution was shortened to 72% of that with normal media.

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