• Title/Summary/Keyword: Cr poisoning

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Electrochemical Performance and Cr Tolerance in a La1-xBaxCo0.9Fe0.1O3-δ (x = 0.3, 0.4 and 0.5) Cathode for Solid Oxide Fuel Cells

  • Choe, Yeong-Ju;Hwang, Hae-Jin
    • Journal of the Korean Ceramic Society
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    • v.52 no.5
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    • pp.308-314
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    • 2015
  • The electrochemical performance and Cr poisoning behavior of $La_{1-x}Ba_xCo_{0.9}Fe_{0.1}O_{3-{\delta}}$ (LBCF, x = 0.3, 0.4, 0.5) and $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-{\delta}}$ (LSCF) cathodes were investigated for solid oxide fuel cells (SOFCs). The polarization resistance of the LBCF/GDC/LBCF symmetrical cell was found to decrease with increasing Ba content (x value). This phenomenon might be associated with the high oxygen vacancy concentration in the LBCF sample, with x = 0.5. In addition, there was no chromium poisoning in the LBCF cathode. On the other hand, the polarization resistance of the LSCF cathode was found to significantly increase after exposure to gaseous chromium species; it appears that this result stemmed from the formation of $SrCrO_4$ phase. Therefore, it can be expected that LBCF can be a durable potential cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFC).

The Effect of Cr from STS Interconnect on the Polarization Resistance of LSCF Cathode (스테인리스 스틸 연결재의 Cr이 LSCF 양극의 분극저항에 미치는 영향)

  • Hwang, Ho-June;Choi, Gyeong-Man
    • Journal of the Korean Ceramic Society
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    • v.44 no.12
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    • pp.715-719
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    • 2007
  • STS444 with or without $La_{0.9}Sr_{0.1}MnO_3$ (LSM)-coating was contacted to $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3$ (LSCF) cathode on various electrolyte materials and the polarization resistance $(R_p)$ was measured by impedance spectroscopy. By making a symmetric half-cell and contacting only one side of the cathode with the interconnect, the effect of chromium (Cr) poisoning was separated from the aging effects. When the LSCF cathode was contacted with LSM-coated STS (stainless steel), $R_p$ of LSCF was lower than that contacted with the uncoated STS. Impedance patterns measured for the working electrode (W.E.), the counter electrode (C.E.) at $600^{\circ}C$ in air were analyzed. Normalized data of net Cr effect showed that $Ce_{0.9}Gd_{0.1}O_2$ (GDC) electrolyte is more tolerant to the chromium poisoning than $La_{0.9}Sr_{0.1}Ga_{0.8}Mg_{0.2}$ (LSGM) or 8 mol% $Y_2O_3-doped$ $ZrO_2$ (YSZ) electrolytes.

Numerical analysis of chromium deposition through the SOFC cathode channel (고체 산화물 연료전지의 공기극 유로내 크롬 피독에 관한 전산해석)

  • Park, Joon-Guen;Bae, Joong-Myeon;Lee, Shin-Ku;Nabielek, Heinz
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.11a
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    • pp.372-375
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    • 2006
  • SOFC is a high temperature fuelcell with many advantages, but it also have several demerits. One of the Issues is cathode poisoning of Cr coming from stainless steel interconnects. Diffusion process of Cr evaporated from the surface of interconnect steel was calculated by using CFD technique to understand factors for Cr deposition. It has been cleared that factors concerned in Cr deposition and how they affect Cr deposition. Major variables for Cr deposit ion are diffusion coefficient, air velocity and temperature If diffusion coefficient decreases, Cr concentration increases in the air but decreases on the cathode surface. Increasing in air velocity, Cr concentration decreases in the air and on the cathode surface. Increase in temperature leads to rising Cr concentration on the cathode surface because of diffusion coefficient increment.

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An Experimental Study on Performance and Exhaust Emission of a Heavy-Duty Engine with CR-DPF (CR-DPF를 장착한 대형디젤기관의 기관 및 배출가스성능에 관한 실험적 연구)

  • Kim mi soo;Oh sang ki;Han young chool
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.6
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    • pp.114-118
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    • 2004
  • This research focused on the principle and the development of continuous regeneration DPF technology which was the best particulate matters removing technology of current existing technologies owing to its superior comparability and possible applicability. In addition, there were some discussions about the affecting engine parameters such as engine driving conditions and the amounts, velocity, temperature, pressure of exhaust emissions as well as sulfur contents and lubricants which were prerequisites to prevent poisoning effect on catalysts. The test was made on an 8000cc heavy-duty turbo diesel engine on which continuous regeneration DPF was in order to investigate regeneration characteristics of DPF and me performance under the condition of standard or 50ppm low sulphur diesel. Exhaust emissions, CO, HC, NOx PM were measured and compared under D-13 modes.

Materials Chemical Point of View for Durability Issues in Solid Oxide Fuel Cells

  • Yokokawa, Harumi;Horita, Teruhisa;Yamaji, Katsuhiko;Kishimoto, Haruo;Brito, M.E.
    • Journal of the Korean Ceramic Society
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    • v.47 no.1
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    • pp.26-38
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    • 2010
  • Degradation in Solid Oxide Fuel Cell performance can be ascribed to the following fundamental processes from the materials chemical point of view; that is, diffusion in solids and reaction with gaseous impurities. For SOFC materials, diffusion in solids is usually slow in operation temperatures $800\sim1000^{\circ}C$. Even at $800^{\circ}C$, however, a few processes are rapid enough to lead to some degradations; namely, Sr diffusion in doped ceria, cation diffusion in cathode materials, diffusion related with metal corrosion, and sintering of nickel anodes. For gaseous impurities, chromium containing vapors are important to know how the chemical stability of cathode materials is related with degradation of performance. For LSM as the most stable cathode among the perovskite-type cathodes, electrochemical reduction reaction of $CrO_3$(g) at the electrochemically active sites is crucial, whereas the rest of the cathodes have the $SrCrO_4$ formation at the point where cathodes meet with the gases, leading to rather complicated processes to the degradations, depending on the amount and distribution of reacted Cr component. These features can be easily generalized to other impurities in air or to the reaction of nickel anodes with gaseous impurities in anode atmosphere.

Prognostic Value of Blood Lactate for Mortality of Acutely Poisoned Patients in Emergency Department (응급실내 급성 중독 환자들의 예후 예측에 대한 혈액 젖산 수치의 유용성)

  • Kim, Hye Ran;Kang, Mun Ju;Kim, Yong Hwan;Lee, Jun Ho;Cho, Kwang Won;Hwang, Seong Youn;Lee, Dong Woo
    • Journal of The Korean Society of Clinical Toxicology
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    • v.14 no.1
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    • pp.16-25
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    • 2016
  • Purpose: Patients suffering from acute poisoning by different substances often visit the emergency department (ED) and receive various prognoses according to the toxic material and patients' condition. Hyperlactatemia, which is an increased blood lactate level that generally indicates tissue hypoperfusion, is commonly utilized as a prognostic marker in critically ill patients such as those with sepsis. This study was conducted to investigate the relationships between blood lactate and clinical prognosis in acute poisoned patients. Methods: This retrospective study was conducted from January 2013 to June 2014 at a single and regional-tertiary ED. We enrolled study patients who were examined for blood test with lactate among acute intoxicated patients. The toxic materials, patient demographics, laboratory data, and mortalities were also reviewed. Additionally, we analyzed variables including blood lactate to verify the correlation with patient mortality. Results: A total of 531 patients were enrolled, including 24 (4.5%) non-survivors. Patient age, Glasgow coma scale (GCS), serum creatinine (Cr), aspartate transaminase (AST), and serum lactate differed significantly between survivors and non-survivors in the binary logistic regression analysis. Among these variables, GCS, AST, and lactate differed significantly. The median serum lactate levels were 2.0 mmol/L among survivors and 6.9 mmol/L among non-survivors. The AUC with the ROC curve and odds ratio of the initial serum lactate were 0.881 and 3.06 (0.89-8.64), respectively. Conclusion: Serum lactate was correlated with fatalities of acute poisoning patients in the ED; therefore, it may be used as a clinical predictor to anticipate their prognoses.

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Comparison of Severity in Organophosphate Insecticide Poisoning Patients Treated with Tracheostomy (기관절개술을 시행한 유기인계 살충제 중독 환자의 중증도 비교)

  • Choo, Dae-Hyuk;Park, Yong-Jin;Kim, Sun-Pyo;Kim, Seog-Jung;Cho, Soo-Hyung;Cho, Nam-Soo
    • Journal of The Korean Society of Clinical Toxicology
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    • v.9 no.2
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    • pp.61-70
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    • 2011
  • Purpose: This study investigated the effect on survival rate for organophosphate intoxication patients who received trachostomy. This research was conducted to help identify appropriate treatment of patients who received a trachostomy. Methods: This research was retrospectively conducted using the medical records of 141 patients who arrived at the Chosun University Hospital emergency medical center between Jan 2007 and Dec 2010, suffering from organophosphate intoxication. They were placed in two groups including one which received trachostomy as part of their treatment and one that did not. The effect of each variable on mortality was evaluated by regressionanalysis. Results: Of 141 patients with organophosphate intoxication, 105 of them did not tracheostomy and 16 were dead cohorts (15.2%). Their size of pupil was 1mm. Factors such as amount of organophosphate ingested, PAM time after ingestion, average body temperature, arrival time, atropinization time after ingestion, AST/ALT, Bun/Cr all appeared to be significant factors in death cohorts (P<0.05). 36 patients among the total had tracheostomy and 11 ones of them were in dead cohort (30.6%) and their average age was 58 years. The facts affect the state of patients in dead cohort include the amount of intoxication which between $327.27{\pm}194.1ml$, performing intubation 686 mins after intubation, reaching to the hospital after 580mins, injecting PAM 744 mins after intoxication, injecting atropine 627 mins after intoxication. The largest cases of patient's state was found to be stupor with 14 patients (38.9%) the level of Cholinesterase in blood appeared to be significant in dead cohort as $391.00{\pm}353.9IU/L$ (P<0.05). Conclusion: Further planned studies are necessary on the use of tracheostomy for treatment of poisoning victims, especially those intoxicated by organophosphorus insecticides.

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Antioxidant and Anti-Inflammatory Effects of Kamisipjeondaebotang in RAW 264.7 Cells (가미십전대보탕의 RAW 264.7 세포에서 항산화 및 항염증 효과)

  • Myung, Jeong-Ho;Lee, Myung-Sun
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.46 no.11
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    • pp.1271-1277
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    • 2017
  • As Kamisipjeondaebotang (KSD) extract is an herbal ingredient, safety is very important due to possible cell poisoning or heavy metal toxicity to organs when administered to humans or animals. Accordingly, this study examined the antioxidant and anti-inflammatory effects of KSD extract to confirm its medicinal safety by using RAW 264.7 cells after heavy metal screening, functional index test of the liver and kidney, and cell survival rate test. Heavy metals were not found in KSD extracts or were less than standard amounts. Liver function indices such as aspartate aminotransferase and alanine aminotransferase revealed low values and kidney function indices such as creatinine and blood urea nitrogen were not significantly different from the normal group. This proved the safety to the human. RAW 264.7 cells showed no poisoning compared to the control group in terms of survival rate. Regarding the antioxidant effect of KSD extract, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and 2,2'-azino-bis(3-ethylbenzothiazo-line-6-sulphonic acid) radical scavenging activity increased at concentrations over $10{\mu}g/mL$. The anti-inflammatory effect of KSD extract significantly decreased based on the amount of nitric oxide at concentrations of 10 and $100{\mu}g/mL$ compared to the control group. Expression of interleukin (IL)-$1{\beta}$ and IL-6 decreased in a concentration-dependent manner. There was no significant difference in tumor necrosis factor-${\alpha}$ level. Based on the results, KSD can be regarded as a safe antioxidant with anti-inflammatory effects for fracture treatment.

Eco-friendly Fabrication Process of Al-Ti-C Grain Refiner

  • Cho, Hoon;Kim, Bong-Hwan
    • Journal of Korea Foundry Society
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    • v.30 no.4
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    • pp.147-150
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    • 2010
  • An eco-friendly production technique of Al-8.6Ti-0.025C refiner was developed by melting a Al-Ti master alloy in a graphite crucible, in which the potential nucleation site, TiC effectively formed by the spontaneous in-situ reaction between excessive Ti and carbon from graphite crucible. The A3003 alloy refined by the Al-8.6Ti-0.025C showed effectively refined macrostructure and enhanced mechanical properties comparable to the commercial Al-Ti-B refiner. The effective refinement was achieved in a shorter compare to the melt-treating time commercial Al-Ti-B refiner.

Minimize Web Applications Vulnerabilities through the Early Detection of CRLF Injection

  • Md. Mijanur Rahman;Md. Asibul Hasan
    • International Journal of Computer Science & Network Security
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    • v.23 no.2
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    • pp.199-202
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    • 2023
  • Carriage return (CR) and line feed (LF), also known as CRLF injection is a type of vulnerability that allows a hacker to enter special characters into a web application, altering its operation or confusing the administrator. Log poisoning and HTTP response splitting are two prominent harmful uses of this technique. Additionally, CRLF injection can be used by an attacker to exploit other vulnerabilities, such as cross-site scripting (XSS). Email injection, also known as email header injection, is another way that can be used to modify the behavior of emails. The Open Web Application Security Project (OWASP) is an organization that studies vulnerabilities and ranks them based on their level of risk. According to OWASP, CRLF vulnerabilities are among the top 10 vulnerabilities and are a type of injection attack. Automated testing can help to quickly identify CRLF vulnerabilities, and is particularly useful for companies to test their applications before releasing them. However, CRLF vulnerabilities can also lead to the discovery of other high-risk vulnerabilities, and it fosters a better approach to mitigate CRLF vulnerabilities in the early stage and help secure applications against known vulnerabilities. Although there has been a significant amount of research on other types of injection attacks, such as Structure Query Language Injection (SQL Injection). There has been less research on CRLF vulnerabilities and how to detect them with automated testing. There is room for further research to be done on this subject matter in order to develop creative solutions to problems. It will also help to reduce false positive alerts by checking the header response of each request. Security automation is an important issue for companies trying to protect themselves against security threats. Automated alerts from security systems can provide a quicker and more accurate understanding of potential vulnerabilities and can help to reduce false positive alerts. Despite the extensive research on various types of vulnerabilities in web applications, CRLF vulnerabilities have only recently been included in the research. Utilizing automated testing as a recurring task can assist companies in receiving consistent updates about their systems and enhance their security.