• Title/Summary/Keyword: corrosive

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Comparative Study Between Geopolymer and Cement Waste Forms for Solidification of Corrosive Sludge

  • Lee, Juhyeok;Kim, Byoungkwan;Kang, Jaehyuk;Kang, Jaeeun;Kim, Won-Seok;Um, Wooyong
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.18 no.4
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    • pp.465-479
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    • 2020
  • Two waste forms, namely cement and geopolymer, were investigated and tested in this study to solidify the corrosive sludge generated from the surface and precipitates of the tubes of steam generators in nuclear power plants. The compressive strength of the cement waste form cured for 28 days was inversely proportional to waste loading (24.4 MPa for 0wt% to 2.7 MPa for 60wt%). The corrosive sludge absorbed the free water in the hydration reaction to decrease the cementation reaction. When the corrosive sludge waste loading increased to 60wt%, the cement waste form showed decreased compressive strength (2.7 MPa), which did not satisfy the acceptance criteria of the repository (3.45 MPa). Meanwhile, the compressive strength of the geopolymer waste form cured for 7 days was proportional to waste loading (23.6 MPa for 0wt% to 31.9 MPa for 40wt%). The corrosive sludge absorbed the free water in the geopolymer when the water content decreased, such that a compact geopolymer structure could be obtained. Consequently, the geopolymer waste forms generally showed higher compressive strengths than cement waste forms.

The Study on the Marine Deaerator (선박용 탈기기에 관한 연구)

  • 홍성희;김창수;김두현
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2002.05a
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    • pp.29-34
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    • 2002
  • As the makeup water entering the boiler feed water cycle usually contains corrosive gases, particularly oxygen and carbon dioxide, so the corrosive gases should be eliminated by a deaerator. While the other domestic companies have made a deaerator for land industrial field, our company has developed and is able to produce a spray & scrubber type deaerator for marine to maintain below the level of 7ppb of dissolved oxygen in the condensate. In this paper, we describe the principle, design technique and experimntal results of the spray & scrubber type deaerator.

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Study on the Corrosive Characters of Carbon Steel in the Marine Splash Zone

  • Zhu, Xiangrong;Han, Bing
    • Corrosion Science and Technology
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    • v.2 no.1
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    • pp.26-29
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    • 2003
  • This study determined that the four corrosive characters of carbon steel in the marine splash zone (MSZ) in China's four sea areas. It has a range and a corrosion peak value. The rust in the MSZ plays the role of "depolarizer" in the cathodic process of corrosion. The growth law of the rust layer in MSZ has a character of "annual ring". In addition the reasons causing serious corrosion of carbon steel in the marine splash zone has been discussed in this paper.

Design of bars in tension or compression exposed to a corrosive environment

  • Fridman, Mark M.;Elishakoff, Isaac
    • Ocean Systems Engineering
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    • v.5 no.1
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    • pp.21-30
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    • 2015
  • This study is devoted to the optimal design of compressed bars under axial tensile or compressive forces and exposed to a corrosive environment. Dolinskii's linear stress corrosion model is adopted for analysis. Analytical and numerical results are derived for optimal variation of the cross-sectional area of the bar along its axis.

Effect of Load and Sliding Speed on Corrosive Wear of Metals in Seawater

  • Kawazoe, T.;Ura, A.;Nakashima, A.;Moritaka, H.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.10b
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    • pp.245-246
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    • 2002
  • The objective of this study is to evaluate corrosive wear resistance of metals used for bearings and gears in seawater. Sliding wear test of ferrous and copper materials against $Al_2O_3$ were carried out in artificial seawater using an electrochemical potentiostat. As the results, the wear rate and the coefficient of friction of the copper materials are lower than those of the ferrous materials. The corrosive wear of stainless steel is remarkably affected by normal load and sliding speed in view of tribological characteristics including adhesion and corrosion products.

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The Anti-Corrosion Properties of Coated Reinforcing Bar Using Polymer Cement Slurry (폴리머 시멘트 슬러리에 의한 철근의 방청성능)

  • 김영집;김연홍;윤보원;조영국;소양섭
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.201-206
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    • 2002
  • The purpose of this study is to improve the anti-corrosive properties of coated reinforcing bar using polymer cement slurry. Poymer cement slurry are prepared with three types of polymer dispersions and corrosion inhibiting admixture. And tested for corrosion accelerating tests such as immersion in NaCl 10% solution NaCl 10% solution spray, high temperature and pressure steam in condition of 8cycles, carbonation before and after, penetration of NaCl solution. From the test results, it is concluded that the anti-corrosive properties are considerably improved by coating using polymer cement slurry at surface of reinforcing bar. And this trend is marked by adding of corrosion inhibiting admixture. The difference of the anti-corrosive properties is hardly recognized according to types of polymer dispersions. The anti-corrosive properties of coated reinforcing bar using polymer foment slurry are improved to a great extent compared to those of plain reinforcing bar accordiy to increasing content of chloride ion in cement concrete.

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Surgical Treatment of Acid Induced Corrosive Esophageal Stricture in Children (소아의 산성 부식성 식도협착의 외과적 치료)

  • Park, Kwi-Won;Yang, Seok-Jin;Chun, Yong-Soon;Jung, Sung-Eun;Lee, Seong-Cheol;Kim, Woo-Ki
    • Advances in pediatric surgery
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    • v.3 no.1
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    • pp.47-53
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    • 1997
  • Accidental ingestion of caustic substance is one of the common problems among children around the world. Acid intake accounts for a mere 5% of all reported cases of corrosive ingestion in the West. Because of the esophageal sparing effect of acid, clinically significant esophageal involvement after acid ingestion occurs in only 6 to 20 percent of the instances. Despite effort of prevention, 7% to 15% of children sustaining caustic esophageal burns develop esophageal strictures. If balloon dilatation or bougie dilatation fails to resolve the esophageal strictures, successful outcome following replacement by colon or stomach has been reported in children. But the complications and morbidity following these operations are still relatively high. Seven patients with corrosive-acid induced esophageal strictures who were operated upon at the Department of Pediatric Surgery, Seoul National University Children's Hospital from 1991 to 1995 were reviewed. Primary resection and anastomosis was performed in all of 7 patients. The stricture involved short segments of the esophagus at the level of the lower cervical and the upper thoracic vertebra. The operations were approached through a left cervical incision or a left thoracotomy. In one patient, operative repair of anastomotic leakage was done, and three patients required re-resection of anastomotic strictures postoperatively, and one patient required a third operation(reversed gastric tube) due to an anastomotic stricture. The other anastomotic leaks, strictures or pulmonary complications were resolved with conservative treatment. In conclusion, primary resection and anastomosis of the esophagus was performed successfully on the 6 of 7 children with acid induced corrosive esophageal strictures. This approach is physiologic, especially in children who should have a long life expectancy, and recommended for the treatment of short-segment acid induced corrosive esophageal strictures.

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Treatment of Corrosive Esophageal Stricture by Transhiatal Esophagectomy and Esophagogastrostomy (경열공 식도절제술을 이용한 부식성 식도협착증의 치료)

  • Kim, Jae-Bum;Park, Chang-Kwon
    • Korean Journal of Bronchoesophagology
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    • v.15 no.1
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    • pp.35-40
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    • 2009
  • Background: Surgical treatment of corrosive esophageal stricture with colon interposition was very widely used. The colon interposition advantage is low reflux esophagitis risk and preservation of gastric capacity and peristalsis. This procedure was introduced by Orsoni and much improved. But, if stomach injury was minimal, gastric interposition is useful due to simple technique and low complication. Material and Method: Esophageal reconstruction by the transhiatal esophagectomy and intracervical esophagogastrostomy was done in 7 patients of corrosive esophageal stricture at Dong-San medical center from January 1998 to December 2007. Result: There were six female and one male patients raBackground Surgical treatment of corrosive esophageal stricture with colon interposition was very widely used. The colon interposition advantage is low reflux esophagitis risk and preservation of gastric capacity and peristalsis. This procedure was introduced by Orsoni and much improved. But, if stomach injury was minimal, gastric interposition is useful due to simple technique and low complication. Material and Method: Esophageal reconstruction by the transhiatal esophagectomy and intracervical esophagogastrostomy was done in 7 patients of corrosive esophageal stricture at Dong-San medical center from January 1998 to December 2007. Result: There were six female and one male patients ranging from 29 to 69 years of age. The complication was two anastomosis site leakage, one gastric necrosis and one mortality due to bowel strangulation and sepsis. Conclusion: Transhiatal esophagectomy and intracervical esophagogastrostomy is safety and useful method at selection case even though corrosive esophageal resection is debated.

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The Effect of Additive to Corrosion Resistance of Heavy Anti-Corrosive Paint (중방식 도료의 내식성에 미치는 첨가제의 영향)

  • Moon, Kyung-Man;Cho, Hwang-Rae;Lee, Myung-Hoon;Kim, Hyun-Myung;Lee, In-Won;Chun, Ho-Hwan
    • Journal of Ocean Engineering and Technology
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    • v.21 no.3 s.76
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    • pp.65-70
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    • 2007
  • There are many kinds of protection methods for marine structures, with varyingeconomical and environmental advantages. The coating protection method is being widely used in both continental and marine structures. In this study, by adding some additives, such as Zn powder(Zn), carbon black(CB) to epoxy anti-corrosive paint, the effect on the corrosion resistance was investigated throughan electrochemical method. The additive of Zn(20)+CB(10) showed the lowest passivity current density. Polarization resistance in both cyclic voltammogram and impedance measurement of an additive of Zn(20)+CB(10) was also the largest value, compared to other additives. Furthermore, rusting and bubbling was not observed on the surface of the test specimen with the additive of Zn(20)+CB(10), compared to other specimens. It is suggested that the corrosion resistance of the anti-corrosive paint can be improved by using some additives.