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Aqueous Polymerization of Acrylamide by N,N-Dimethylaniline-Cobaltous Chloride
Sur, Gil Soo 嶺南大學校 工業技術硏究所 1979 연구보고 Vol.7 No.1
N,N-Dimethylaniline(DMA)와 염화코발트를 개시제로 사용하여 질소 기류하의 수용액 중에서 30-50℃에서 acrylamide의 중합을 시도하였다. 중합속도는 0.5-2.0× mol/ℓ 범위에서 단량체 농도의 1.08승의 비례함을 발견하였다. 또 염화코발트의 반응차수는 0.53차이었으며, 이것으로부터 0.2-2.0× mol/ℓ 범위내에서 최종 반응의 반응 mechanism을 예측할 수 있었다. 중합속도와 최대 전환율은 반응 온도가 40℃ 이상에서는 낮아졌다. 또 30-50℃의 온도 범위에서 활성화 energy는 9.38Kcal/mol이었다. Methanol을 투입하였을 땐 중합속도가 줄어들었고, benzoquinone을 투입하였을 땐 induction period 동안 반응이 완전 중지되었다. 실험결과로부터 반응 mechanism을 제안하였다. The pair of cobaltous chloride with N,N-dimethylaniline (DMA) nas been investigated as an initiator for the polymerization of acrylamide in aqueous media at 30, 40, and 50℃ in a nitrogen atmosphere. The rate of polymerization was found to be proportional the monomer concentration to the power of 1.08 over the range of 0.5-2.0× mol/ℓ. The reaction order related to the cobaltous chloride concentration was 0.53, which indicated a bimolecular mechanism for the termination reaction in the range of 0.2-2.0× mol/ℓ. The rate of polymerization and the maximum conversion was decreased the temperature was above 40℃. The apparent activation energy was 9.38Kcal/mol in the temperature range of 30-50℃. The rate of polymerization was decreased as adding methanol in the reactant, and was completely stopped during an induction period caused when benzoquinone was added in it. The reaction mechanism was proposed on the basis of the experimental data.
Variation of tropospheric NO2 over Indo-Gangetic plain during COVID-19 outbreak in India
Sur Koyel,Verma Vipan Kumar,Pateriya Brijendra 대한공간정보학회 2021 Spatial Information Research Vol.29 No.6
Nitrogen dioxide (NO2) is a gaseous air pollutant which primarily gets in the air when fossil fuels such as coal, oil, gas or diesel are burned at high temperatures through industries, power plant, automobiles and locomotive. Continuous exposure to elevated concentration of NO2 may impose development of asthma and potentially increase in susceptibility to respiratory infections in humans. The present study examined impact of lockdown due to COVID-19 in terms of spatial and temporal variation of tropospheric NO2 in Indo-Gangetic plain. The results showed steep reduction in tropospheric NO2 as a result of ceased industrial and economic activities. Analysis of Sentinel-5P satellite data was carried out for specific period during 2019–2020 at a regional scale and for major industrial cities. Tremendous positive impact of lockdown in atmospheric condition is observed, wherein NO2 concentration has gone down by 20–40% in all major cities except few exceptions were noticed. The concomitant impact of Covid-19 has ensued pragmatic constructive impact on environment and climate, due to drop in NO2 emissions.
Sur Bongjun,Kim Mijin,Villa Thea,Oh Seikwan 한국응용약물학회 2023 Biomolecules & Therapeutics(구 응용약물학회지) Vol.31 No.5
Phytoceramide (Pcer) is found mainly in plants and yeast. It can be neuroprotective and immunostimulatory on various cell types. In this study, the therapeutic effect of Pcer was explored using the carrageenan/kaolin (C/K)-induced arthritis rat model and fibroblast-like synoviocytes (FLS). Pcer treatment (1, 10, and 30 mg/kg/day) were given to the arthritic rats for 6 days after disease induction. Weight distribution ration (WDR), knee thickness, squeaking score, serum levels of proinflammatory mediators, and histological analysis were measured and performed to evaluate arthritic symptoms in the rat model. In interleukin (IL)‑1β‑stimulated FLS, proinflammatory mediators were measured after Pcer (1-30 μM) treatment. Arthritic symptoms in rats with Pcer treatment were significantly decreased at days 4 to 6 after C/K arthritis induction. Inflammation in the knee joints were also significantly decreased in rats with Pcer treatment. Furthermore, in IL-1β‑stimulated FLS, the expressions of proinflammatory mediators were also inhibited by Pcer. As shown by the results, Pcer has anti-arthritic effects in the C/K rat model and in synovial cells, suggesting that Pcer has the potential to be a useful agent in arthritis treatment.
Sur Aslihan,Iflazoglu Mutlu Seda,Tatli Seven Pinar,Seven Ismail,Aslan Abdullah,Kizil Meltem,Kulaksiz Recai,Yaranoglu Mustafa Hilmi,Esen Selim 한국독성학회 2023 Toxicological Research Vol.39 No.4
In this study, we investigated the effects of grape seed proanthocyanidin extract (GSPE) against the side effects of highdose administration of methylprednisolone (MP) in male rats. A total of 32 adult Wistar male albino rats were divided into four groups: (1) control (CON), received standard food only; (2) MP, received standard food + intraperitoneal injection of 60 mg/kg MP on day 7; (3) GSPE, received standard food + 200 mg/kg/day GSPE; and (4) MP + GSPE, received standard food + 200 mg/kg/day of GSPE + intraperitoneal injection of 60 mg/kg MP on day 7. All animals in the GSPE and GSPE + MP groups were treated once a day by oral gavage for 14 consecutive days. The feed intake of rats in the MP and MP + GSPE groups decreased significantly by 24.14% and 13.52%, respectively (p < 0.05). Administration of MP resulted in significant increases in serum concentrations of blood urea nitrogen (p < 0.001), glucose (p < 0.01), alkaline phosphatase, and adrenocorticotropic hormone (p < 0.05). High-dose MP administration significantly reduced catalase (p < 0.001) and glutathione peroxidase (p < 0.05) concentrations in the liver and kidney tissues of rats, while glutathione concentrations were only reduced in liver tissue (p < 0.05). The expression levels of Bcl-2 and TNF-α in liver, kidney, and testicular tissue were significantly increased, while the expression levels of caspase-3 were reduced (p < 0.001). Furthermore, sperm concentration was significantly affected by GSPE in rats induced by high-dose MP, and sperm loss was significantly reduced in MP + GSPE (p < 0.05). These findings suggest that GSPE could be useful as a supplement to alleviate MP-induced toxicity in rats.
Development of a Numerical Methodology for Analysis and Design of Weldments
Sur, Ukhwan The Korean Society of Mechanical Engineers 2001 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.15 No.4
There are many analysis formulas for determining the resultant shear force in welds. However, there is no general procedure which is applicable to a joint with all six possible loadings exerted simultaneously. A numerical methodology and computer program for such a problem were developed, and they are capable of analyzing a weld of any shape composed of straight or circular line segments. The computer program developed in this study can also display the design procedures and results using computer graphics. The development of such a design procedure and an interactive computer program for weldments analysis will lead to lower cost.
Sur, Uk-Hwan Korean Nuclear Society 2011 Nuclear Engineering and Technology Vol.43 No.4
This paper is a study on a nuclear water chiller. It presents a test-verified finite element model of a water chiller to be used at a Nuclear Power Plant. The test-verified model predicts natural frequencies within 5% for all major modes below 50 Hz. This model accurately represents the dynamic characteristics of the actual hardware and is qualified for its use in the final stress analysis for seismic verification.