Charlotte E Warren, Pooja Sripad, Charity Ndwiga, Chantalle Okondo, Felicitas M Okwako, Caroline W Mwangi, Timothy Abuya
Enhancing respectful, responsive, integrative, and nurturing care for hospitalized newborns and young children (aged 0-24 months) is globally recognized but under-researched in low- and middle-income countries. Responsive, family-centered interventions target providers and parents and emphasize partnership in caring roles. From February 2020 to August 2021, we engaged in a participatory co-creation process with parents, providers, and newborn and child health stakeholders in Kenya to develop a comprehensive provider behavior change intervention and implemented it across 5 hospitals in Nairobi and Bungoma counties in Kenya. The multifaceted intervention included a 7-module orientation, feedback meetings, job aids, and psychosocial support-leveraging in-person and remote modalities-for providers working in newborn and pediatric units. We used a mixed-methods evaluation drawing on a pre-post provider survey, pre-post qualitative interviews with providers and parents, and a follow-up parental survey. There were significant post-intervention improvements in provider knowledge on safeguarding sleep, positioning and handling, and protecting skin. However, there were also significant reductions in providers' knowledge in identifying a child's pain, parental stress, and environmental stress. Among parents who received coaching from providers, there were higher levels of interpersonal communication between parent and provider, parental empowerment, and improved ability to provide integrated, responsive care to their child. Despite the challenges of implementing a provider-focused intervention to improve care for hospitalized newborns and young children during the global COVID-19 pandemic, we have demonstrated that it is feasible to implement a hybrid virtual and in-person process to influence several outcomes, including provider knowledge and practice, improved provider partnerships with parents, and parents' capacity to engage in the care of their newborn or young child.
{"title":"Lessons From a Behavior Change Intervention to Improve Provider-Parent Partnerships and Care for Hospitalized Newborns and Young Children in Kenya.","authors":"Charlotte E Warren, Pooja Sripad, Charity Ndwiga, Chantalle Okondo, Felicitas M Okwako, Caroline W Mwangi, Timothy Abuya","doi":"10.9745/GHSP-D-23-00004","DOIUrl":"10.9745/GHSP-D-23-00004","url":null,"abstract":"<p><p>Enhancing respectful, responsive, integrative, and nurturing care for hospitalized newborns and young children (aged 0-24 months) is globally recognized but under-researched in low- and middle-income countries. Responsive, family-centered interventions target providers and parents and emphasize partnership in caring roles. From February 2020 to August 2021, we engaged in a participatory co-creation process with parents, providers, and newborn and child health stakeholders in Kenya to develop a comprehensive provider behavior change intervention and implemented it across 5 hospitals in Nairobi and Bungoma counties in Kenya. The multifaceted intervention included a 7-module orientation, feedback meetings, job aids, and psychosocial support-leveraging in-person and remote modalities-for providers working in newborn and pediatric units. We used a mixed-methods evaluation drawing on a pre-post provider survey, pre-post qualitative interviews with providers and parents, and a follow-up parental survey. There were significant post-intervention improvements in provider knowledge on safeguarding sleep, positioning and handling, and protecting skin. However, there were also significant reductions in providers' knowledge in identifying a child's pain, parental stress, and environmental stress. Among parents who received coaching from providers, there were higher levels of interpersonal communication between parent and provider, parental empowerment, and improved ability to provide integrated, responsive care to their child. Despite the challenges of implementing a provider-focused intervention to improve care for hospitalized newborns and young children during the global COVID-19 pandemic, we have demonstrated that it is feasible to implement a hybrid virtual and in-person process to influence several outcomes, including provider knowledge and practice, improved provider partnerships with parents, and parents' capacity to engage in the care of their newborn or young child.</p>","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":"10 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10698236/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88722004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-31DOI: 10.14773/CST.2021.20.5.295
Jin-seong Park, Du Yun, H. Seong, Sung Jin Kim, 박진성, 윤덕빈, 성환구, 김성진
{"title":"Effect of ε-carbide (Fe 2.4 C) on Corrosion and Hydrogen Diffusion Behaviors of Automotive Ultrahigh-Strength Steel Sheet, 초고강도급 자동차용 강재 내 ε-carbide (Fe 2.4 C)가 부식 및 수소확산거동에 미치는 영향","authors":"Jin-seong Park, Du Yun, H. Seong, Sung Jin Kim, 박진성, 윤덕빈, 성환구, 김성진","doi":"10.14773/CST.2021.20.5.295","DOIUrl":"https://doi.org/10.14773/CST.2021.20.5.295","url":null,"abstract":"","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":"46 1","pages":"295-307"},"PeriodicalIF":0.6,"publicationDate":"2021-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41310523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-31DOI: 10.14773/CST.2021.20.4.175
D. U. Lee, Shivshankar Chaudhari, Seungyong Choi, M. Moon, MinYoung Shon
Magnesium alloy is limited in the industrial field because its standard electrode potential is -2.363 V vs. NHE (Normal Hydrogen Electrode) at 25 ℃. This high electrochemical activity causes magnesium to quickly corrode with oxygen in air; chemical conversion coating prevents corrosion but causes surface defects like cracks and pores. We have examined the anti-corrosion effect of sol-gel coating sealed on the defected conversion coating layer. Sol-gel coatings produced higher voltage current and smaller pore than the chemical conversion coating layer. The conversion coating on magnesium alloy AZ31 was prepared using phosphate-permanganate solution. The sol-gel coating was designed using trimethoxymethylsilane (MTMS) and (3-Glycidyloxypropyl) trimethoxysilane (GPTMS) as precursors, and aluminum acetylacetonate as a ring-opening agent. The thermal shock resistance was tested by exposing specimens at 140 ℃ in a convection oven; the results showed changes in the magnesium alloy AZ31 surface, such as oxidization and cracking. Scanning electron microscope (FE-SEM) analysis confirmed a sealed sol-gel coating layer on magnesium alloy AZ31. Electrochemical impedance spectroscopy (EIS) measured the differences in corrosion protection properties by sol-gel and conversion coatings in 0.35 wt% NaCl solution, and the potentiodynamic polarization test and confirmed conversion coating with the sol-gel coating show significantly improved resistance by crack sealing.
{"title":"A Study on the Corrosion Behavior of Magnesium Alloy Sealed with Chemical Conversion Coating and Sol-gel Coating","authors":"D. U. Lee, Shivshankar Chaudhari, Seungyong Choi, M. Moon, MinYoung Shon","doi":"10.14773/CST.2021.20.4.175","DOIUrl":"https://doi.org/10.14773/CST.2021.20.4.175","url":null,"abstract":"Magnesium alloy is limited in the industrial field because its standard electrode potential is -2.363 V vs. NHE (Normal Hydrogen Electrode) at 25 ℃. This high electrochemical activity causes magnesium to quickly corrode with oxygen in air; chemical conversion coating prevents corrosion but causes surface defects like cracks and pores. We have examined the anti-corrosion effect of sol-gel coating sealed on the defected conversion coating layer. Sol-gel coatings produced higher voltage current and smaller pore than the chemical conversion coating layer. The conversion coating on magnesium alloy AZ31 was prepared using phosphate-permanganate solution. The sol-gel coating was designed using trimethoxymethylsilane (MTMS) and (3-Glycidyloxypropyl) trimethoxysilane (GPTMS) as precursors, and aluminum acetylacetonate as a ring-opening agent. The thermal shock resistance was tested by exposing specimens at 140 ℃ in a convection oven; the results showed changes in the magnesium alloy AZ31 surface, such as oxidization and cracking. Scanning electron microscope (FE-SEM) analysis confirmed a sealed sol-gel coating layer on magnesium alloy AZ31. Electrochemical impedance spectroscopy (EIS) measured the differences in corrosion protection properties by sol-gel and conversion coatings in 0.35 wt% NaCl solution, and the potentiodynamic polarization test and confirmed conversion coating with the sol-gel coating show significantly improved resistance by crack sealing.","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":"20 1","pages":"175-182"},"PeriodicalIF":0.6,"publicationDate":"2021-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46287371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-31DOI: 10.14773/CST.2021.20.4.189
S. Hwang, Sung-Woo Kim, M. J. Choi, S. Cho, Dongjun Kim
A technology for designing and licensing a dedicated radiation shielding facility needs to be developed for safe and efficient operation an R&D center. Technology development is important for smooth operation of such facilities. Causes of damage to internal structures (such as baffle former bolt (BFB) of pressurized water reactor) of a nuclear power reactor should be analyzed along with prevention and countermeasures for similar cases of other plants. It is important to develop technologies that can comprehensively analyze various characteristics of internal structures of long term operated reactors. In high-temperature, high-pressure operating environment of nuclear power plants, cases of BFB cracks caused by irradiated assisted stress corrosion cracks (IASCC) have been reported overseas. The integrity of a reactor’s internal structure has emerged as an important issue. Identifying the cause of the defect is requested by the Korean regulatory agency. It is also important to secure a foundation for testing technology to demonstrate the operating environment for medium-level irradiated testing materials. The demonstration testing facility can be used for research on material utilization of the plant, which might have highest fluence on the internal structure of a reactor globally.
{"title":"Failure Evaluation Plan of a Reactor Internal Components of a Decommissioned Plant","authors":"S. Hwang, Sung-Woo Kim, M. J. Choi, S. Cho, Dongjun Kim","doi":"10.14773/CST.2021.20.4.189","DOIUrl":"https://doi.org/10.14773/CST.2021.20.4.189","url":null,"abstract":"A technology for designing and licensing a dedicated radiation shielding facility needs to be developed for safe and efficient operation an R&D center. Technology development is important for smooth operation of such facilities. Causes of damage to internal structures (such as baffle former bolt (BFB) of pressurized water reactor) of a nuclear power reactor should be analyzed along with prevention and countermeasures for similar cases of other plants. It is important to develop technologies that can comprehensively analyze various characteristics of internal structures of long term operated reactors. In high-temperature, high-pressure operating environment of nuclear power plants, cases of BFB cracks caused by irradiated assisted stress corrosion cracks (IASCC) have been reported overseas. The integrity of a reactor’s internal structure has emerged as an important issue. Identifying the cause of the defect is requested by the Korean regulatory agency. It is also important to secure a foundation for testing technology to demonstrate the operating environment for medium-level irradiated testing materials. The demonstration testing facility can be used for research on material utilization of the plant, which might have highest fluence on the internal structure of a reactor globally.","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":"20 1","pages":"189-195"},"PeriodicalIF":0.6,"publicationDate":"2021-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41501604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-31DOI: 10.14773/CST.2021.20.4.169
Chan-Young Lee
{"title":"Application of High Performance Coatings for Service Life Extension of Steel Bridge Coatings","authors":"Chan-Young Lee","doi":"10.14773/CST.2021.20.4.169","DOIUrl":"https://doi.org/10.14773/CST.2021.20.4.169","url":null,"abstract":"","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":"20 1","pages":"169-174"},"PeriodicalIF":0.6,"publicationDate":"2021-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46274709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-31DOI: 10.14773/CST.2021.20.4.210
황성식, 최민재, 김성우, 김동진
To safely operate domestic nuclear power plants approaching the end of their design life, the material degradation management strategy of the components is important. Among studies conducted to improve the soundness of nuclear reactor components, research methods for understanding the degradation of reactor internals and preparing management strategies were surveyed. Since the IGSCC (Intergranular Stress Corrosion Cracking) initiation and propagation process is associated with metal dissolution at the crack tip, crack initiation sensitivity was decreased in the hydrogenated water with decreased crack sensitivity but occurrence of small surface cracks increased. A stress of 50 to 55% of the yield strength of the irradiated materials was required to cause IASCC (Irradiation Assisted Stress Corrosion Cracking) failure at the end of the reactor operating life. In the threshold-stress analysis, IASCC cracks were not expected to occur until the end of life at a stress of less than 62% of the investigated yield strength, and the IASCC critical dose was determined to be 4 dpa (Displacement Per Atom). The stainless steel surface oxide was composed of an internal Cr-rich spinel oxide and an external Fe and Ni-rich oxide, regardless of the dose and applied strain level.
{"title":"원자로 내부구조물 균열개시 민감도에 미치는 영향인자 고찰","authors":"황성식, 최민재, 김성우, 김동진","doi":"10.14773/CST.2021.20.4.210","DOIUrl":"https://doi.org/10.14773/CST.2021.20.4.210","url":null,"abstract":"To safely operate domestic nuclear power plants approaching the end of their design life, the material degradation management strategy of the components is important. Among studies conducted to improve the soundness of nuclear reactor components, research methods for understanding the degradation of reactor internals and preparing management strategies were surveyed. Since the IGSCC (Intergranular Stress Corrosion Cracking) initiation and propagation process is associated with metal dissolution at the crack tip, crack initiation sensitivity was decreased in the hydrogenated water with decreased crack sensitivity but occurrence of small surface cracks increased. A stress of 50 to 55% of the yield strength of the irradiated materials was required to cause IASCC (Irradiation Assisted Stress Corrosion Cracking) failure at the end of the reactor operating life. In the threshold-stress analysis, IASCC cracks were not expected to occur until the end of life at a stress of less than 62% of the investigated yield strength, and the IASCC critical dose was determined to be 4 dpa (Displacement Per Atom). The stainless steel surface oxide was composed of an internal Cr-rich spinel oxide and an external Fe and Ni-rich oxide, regardless of the dose and applied strain level.","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":"20 1","pages":"210-229"},"PeriodicalIF":0.6,"publicationDate":"2021-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41369946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-31DOI: 10.14773/CST.2021.20.4.183
Youngmo Yang, H. Seo
The increasing demand for energy storage in mobile electronic devices and electric vehicles has emphasized the importance of electrochemical energy storage devices such as Li-ion batteries (LIBs) and supercapacitors. For reversible Li storage, alternative anode materials are actively being developed. In this study, we designed and fabricated an Nb2O5-Li3VO4 composite for use as an anode material in LIBs and hybrid supercapacitors. Nb2O5 powders were dissolved into a solution and the precursors were precipitated onto Li3VO4 through a simple, low-temperature hydrothermal reaction. The annealing process yielded an Nb2O5-Li3VO4 composite that was characterized by X-ray diffraction, electron microscopy, and X-ray photoelectron spectroscopy. Electrochemical tests revealed that the Nb2O5-Li3VO4 composite electrode demonstrated increased capacities of approximately 350 and 140 mAh g-1 at 0.1 and 5 C, respectively, were maintained up to 1000 cycles. The reversible capacity and rate capability of the composite electrode were enhanced compared to those of pure Nb2O5-based electrodes. These results can be attributed to the microstructure design of the synthesized composite material.
{"title":"Electrochemical Characteristics of Synthesized Nb 2 O 5 -Li 3 VO 4 Composites as Li Storage Materials","authors":"Youngmo Yang, H. Seo","doi":"10.14773/CST.2021.20.4.183","DOIUrl":"https://doi.org/10.14773/CST.2021.20.4.183","url":null,"abstract":"The increasing demand for energy storage in mobile electronic devices and electric vehicles has emphasized the importance of electrochemical energy storage devices such as Li-ion batteries (LIBs) and supercapacitors. For reversible Li storage, alternative anode materials are actively being developed. In this study, we designed and fabricated an Nb2O5-Li3VO4 composite for use as an anode material in LIBs and hybrid supercapacitors. Nb2O5 powders were dissolved into a solution and the precursors were precipitated onto Li3VO4 through a simple, low-temperature hydrothermal reaction. The annealing process yielded an Nb2O5-Li3VO4 composite that was characterized by X-ray diffraction, electron microscopy, and X-ray photoelectron spectroscopy. Electrochemical tests revealed that the Nb2O5-Li3VO4 composite electrode demonstrated increased capacities of approximately 350 and 140 mAh g-1 at 0.1 and 5 C, respectively, were maintained up to 1000 cycles. The reversible capacity and rate capability of the composite electrode were enhanced compared to those of pure Nb2O5-based electrodes. These results can be attributed to the microstructure design of the synthesized composite material.","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":"20 1","pages":"183-188"},"PeriodicalIF":0.6,"publicationDate":"2021-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43795316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-30DOI: 10.14773/CST.2021.20.3.158
임연수, 김동진, 황성식, 최민재, 조성환
Austenitic 316 stainless steel was irradiated with protons accelerated by an energy of 2 MeV at 360 ℃, the various defects induced by this proton irradiation were characterized with microscopic equipment. In our observations irradiation defects such as dislocations and micro-voids were clearly revealed. The typical irradiation defects observed differed according to depth, indicating the evolution of irradiation defects follows the characteristics of radiation damage profiles that depend on depth. Surface oxidation tests were conducted under the simulated primary water conditions of a pressurized water reactor (PWR) to understand the role irradiation defects play in surface oxidation behavior and also to investigate the resultant irradiation assisted stress corrosion cracking (IASCC) susceptibility that occurs after exposure to PWR primary water. We found that Cr and Fe became depleted while Ni was enriched at the grain boundary beneath the surface oxidation layer both in the non-irradiated and proton-irradiated specimens. However, the degree of Cr/Fe depletion and Ni enrichment was much higher in the proton-irradiated sample than in the non-irradiated one owing to radiation-induced segregation and the irradiation defects. The microstructural and microchemical changes induced by proton irradiation all appear to significantly increase the susceptibility of austenitic 316 stainless steel to IASCC.
{"title":"양성자 조사가 316 스테인리스강의 미세조직과 표면산화 특성에 미치는 영향","authors":"임연수, 김동진, 황성식, 최민재, 조성환","doi":"10.14773/CST.2021.20.3.158","DOIUrl":"https://doi.org/10.14773/CST.2021.20.3.158","url":null,"abstract":"Austenitic 316 stainless steel was irradiated with protons accelerated by an energy of 2 MeV at 360 ℃, the various defects induced by this proton irradiation were characterized with microscopic equipment. In our observations irradiation defects such as dislocations and micro-voids were clearly revealed. The typical irradiation defects observed differed according to depth, indicating the evolution of irradiation defects follows the characteristics of radiation damage profiles that depend on depth. Surface oxidation tests were conducted under the simulated primary water conditions of a pressurized water reactor (PWR) to understand the role irradiation defects play in surface oxidation behavior and also to investigate the resultant irradiation assisted stress corrosion cracking (IASCC) susceptibility that occurs after exposure to PWR primary water. We found that Cr and Fe became depleted while Ni was enriched at the grain boundary beneath the surface oxidation layer both in the non-irradiated and proton-irradiated specimens. However, the degree of Cr/Fe depletion and Ni enrichment was much higher in the proton-irradiated sample than in the non-irradiated one owing to radiation-induced segregation and the irradiation defects. The microstructural and microchemical changes induced by proton irradiation all appear to significantly increase the susceptibility of austenitic 316 stainless steel to IASCC.","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":"20 1","pages":"158-168"},"PeriodicalIF":0.6,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46351075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-30DOI: 10.14773/CST.2021.20.3.143
박일초
In this study, optimal shot peening process conditions were investigated for improving the cavitation erosion resistance of gray cast iron under a marine environment. Shot peening was performed with variables of injection pressure and injection time. The durability was then evaluated through cavitation erosion test which was conducted according to the modified ASTM G-32 standard. The tendency of cavitation erosion damage according to shot peening process condition was investigated through weight loss rate, surface and cross-sectional analysis of the specimen before and after the test. As a result, the shot peening process condition that could minimize cavitation erosion was when the injection pressure was the lowest and when the injection time was the shortest. This was because the flake graphite exposed on the gray cast iron surface could be easily removed under such condition. Therefore, the notch effect can be prevented by surface modification. In addition, the cavitation erosion damage mechanism of gray cast iron was discussed in detail.
{"title":"쇼트피닝이 회주철의 캐비테이션 침식 저항성에 미치는 영향","authors":"박일초","doi":"10.14773/CST.2021.20.3.143","DOIUrl":"https://doi.org/10.14773/CST.2021.20.3.143","url":null,"abstract":"In this study, optimal shot peening process conditions were investigated for improving the cavitation erosion resistance of gray cast iron under a marine environment. Shot peening was performed with variables of injection pressure and injection time. The durability was then evaluated through cavitation erosion test which was conducted according to the modified ASTM G-32 standard. The tendency of cavitation erosion damage according to shot peening process condition was investigated through weight loss rate, surface and cross-sectional analysis of the specimen before and after the test. As a result, the shot peening process condition that could minimize cavitation erosion was when the injection pressure was the lowest and when the injection time was the shortest. This was because the flake graphite exposed on the gray cast iron surface could be easily removed under such condition. Therefore, the notch effect can be prevented by surface modification. In addition, the cavitation erosion damage mechanism of gray cast iron was discussed in detail.","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":"20 1","pages":"143-151"},"PeriodicalIF":0.6,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42453920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-30DOI: 10.14773/CST.2021.20.3.129
H. Jang
Effects of corrosion inhibitors (i.e., sodium nitrite, sodium hexametaphosphate, trimethylamine (TEA), sugar, and urea) on the corrosion resistance of carbon steel in CaCl2 solution were investigated. The test solution was designed with response surface methodology of design of experiments (DOE) in the range of 0 ~ 50 ppm for NaNO2, 0 ~ 200 ppm for (NaPO3)6, 0 ~ 2000 ppm for TEA, 0 ~ 3000 ppm for sugar, 0 ~ 200 ppm for urea with 3 wt% CaCl2. The corrosion potential and the corrosion rate were measured with potentiodynamic polarization tests and analyzed statistically to find main effects of inhibitor concentrations and interactions between them. As a result, hexametaphosphate was the most effective compound in reducing the corrosion rate. Sugar also reduced the corrosion rate significantly possibly because it covered the surface effectively with a high molecular weight. The inhibiting action of sugar was found to be enhanced by adding trimethylamine into the solution. Nevertheless, trimethylamine did not appear to be effective in inhibiting corrosion by itself. However, urea and sodium nitrite showed almost no inhibition on corrosion resistance of steel.
{"title":"Effects of Inhibitors on Corrosion Resistance of Steel in CaCl 2 Solution Based on Response Surface Analysis","authors":"H. Jang","doi":"10.14773/CST.2021.20.3.129","DOIUrl":"https://doi.org/10.14773/CST.2021.20.3.129","url":null,"abstract":"Effects of corrosion inhibitors (i.e., sodium nitrite, sodium hexametaphosphate, trimethylamine (TEA), sugar, and urea) on the corrosion resistance of carbon steel in CaCl2 solution were investigated. The test solution was designed with response surface methodology of design of experiments (DOE) in the range of 0 ~ 50 ppm for NaNO2, 0 ~ 200 ppm for (NaPO3)6, 0 ~ 2000 ppm for TEA, 0 ~ 3000 ppm for sugar, 0 ~ 200 ppm for urea with 3 wt% CaCl2. The corrosion potential and the corrosion rate were measured with potentiodynamic polarization tests and analyzed statistically to find main effects of inhibitor concentrations and interactions between them. As a result, hexametaphosphate was the most effective compound in reducing the corrosion rate. Sugar also reduced the corrosion rate significantly possibly because it covered the surface effectively with a high molecular weight. The inhibiting action of sugar was found to be enhanced by adding trimethylamine into the solution. Nevertheless, trimethylamine did not appear to be effective in inhibiting corrosion by itself. However, urea and sodium nitrite showed almost no inhibition on corrosion resistance of steel.","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":"20 1","pages":"129-142"},"PeriodicalIF":0.6,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48173499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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