Probe on hard carbon electrode derived from orange peel for energy storage application

Meenatchi T.,Priyanka V.,Subadevi R.,Liu Wei-Ren,Huang Chia-Hung,Sivakumar M. 한국탄소학회 2021 Carbon Letters Vol.31 No.5

Activated non-graphitizable hard carbon using orange peel with mesoporous structure has been prepared by pyrolyzation at 700, 800, 900 °C using chemical activation method. The activated orange peel-derived hard carbon has been characterized for its mesoporous and disordered structure. TG-DSC gives the information for the changes about sample composition and thermal stability of the materials. Increasing the carbonization temperature for orange peel precursor using NaOH as activating agent, elevates the pore diameter, which thereby facilitating the insertion of Na+. Raman and X-ray difraction confrms the presence of disordered carbon. The surface morphology of the material was analyzed by scanning eletron microsope and nitrogen (N2) adsorption and desorption analysis give the morphology, mesopore size (3.374, 3.39 and 4 nm) and surace area (60.164, 58.99 and 54.327 m2 /g) of the orange peel-derived hard carbon. Hence, this work strongly evidences that the biomass-derived hard carbon with good porosity and paves way of superior electrochemical performance for emerging sodium ion batteries.

Self-Assembly of Dendronized Perylene Bisimides into Complex Helical Columns

Percec, Virgil,Peterca, Mihai,Tadjiev, Timur,Zeng, Xiangbing,Ungar, Goran,Leowanawat, Pawaret,Aqad, Emad,Imam, Mohammad R.,Rosen, Brad M.,Akbey, Umit,Graf, Robert,Sekharan, Sivakumar,Sebastiani, Danie American Chemical Society 2011 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.133 No.31

<P>The synthesis of perylene 3,4:9,10-tetracarboxylic acid bisimides (PBIs) dendronized with first-generation dendrons containing 0 to 4 methylenic units (<I>m</I>) between the imide group and the dendron, (3,4,5)12G1-<I>m</I>-PBI, is reported. Structural analysis of their self-organized arrays by DSC, X-ray diffraction, molecular modeling, and solid-state <SUP>1</SUP>H NMR was carried out on oriented samples with heating and cooling rates of 20 to 0.2 °C/min. At high temperature, (3,4,5)12G1-<I>m</I>-PBI self-assemble into 2D-hexagonal columnar phases with intracolumnar order. At low temperature, they form orthorhombic (<I>m</I> = 0, 2, 3, 4) and monoclinic (<I>m</I> = 1) columnar arrays with 3D periodicity. The orthorhombic phase has symmetry close to hexagonal. For <I>m</I> = 0, 2, 3, 4 ,they consist of tetramers as basic units. The tetramers contain a pair of two molecules arranged side by side and another pair in the next stratum of the column, turned upside-down and rotated around the column axis at different angles for different <I>m</I>. In contrast, for <I>m</I> = 1, there is only one molecule in each stratum, with a four-strata 2<SUB>1</SUB> helical repeat. All molecules face up in one column, and down in the second column, of the monoclinic cell. This allows close and extended π-stacking, unlike in the disruptive up–down alteration from the case of <I>m</I> = 0, 2, 3, 4. Most of the 3D structures were observed only by cooling at rates of 1 °C/min or less. This complex helical self-assembly is representative for other classes of dendronized PBIs investigated for organic electronics and solar cells.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2011/jacsat.2011.133.issue-31/ja204366b/production/images/medium/ja-2011-04366b_0026.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja204366b'>ACS Electronic Supporting Info</A></P>

농업기상학의 역사

M.V.K. Sivakumar 한국농림기상학회 2004 한국농림기상학회지 Vol.6 No.2

Agricultural meteorology has advanced during the last 100 years from a descriptive to a quantitativescience using physical and biological principles. The agricultural comunity is becoming more aware thatusing climate and weather information will improve their profitability and this will no doubt increase thedemand for agrometeorological services. Hence it is timely that the needs and perspectives foragrometeorology in the 21st Century are grouped under two major headings: agrometeorological servicesfor agricultural production and agrometeorological support systems for such services. Emphasis must beplaced on the components of such suport systems comprising of data, research, policies and training/education/extension. As Monteith (2000) mentioned, food supplies ultimately depend upon the skill withwhich farmers can exploit the potential of good weather and minimize the impact of bad weather. Recentdissemination of agrometeorological information etc., provide agrometeorologists the tools necesary helpthe farmers improve such skills. The future for operational applications of agricultural meteorologyappears bright and such applications could contribute substantially to promote sustainable agricultureand alleviate poverty.

A Contribution to Environmentally-Compatible Energy Conversion: Characterization of Nano Structured Natural Ester Oil Decorated with Carbon Quantum Dots

M. Sivakumar,S.Chandrasekar,P. Uthirakumar,G. C. Montanari 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.6

Performance of natural ester oils have not been investigated deeply yet, and concerns exist about their behavior under overstresses and partial discharges. The present work investigates the suitability of novel carbon quantum dots (CQD) decorated nanostructured natural ester based corn oil for transformer insulation applications, particularly focusing on collecting database for overstressed conditions due to lightning impulse (LI) and partial discharge (PD). CQD nanofl uids prepared with SiO 2 and TiO 2 nanofi llers are tested for its insulation properties such as PD, LI and AC power frequency breakdown voltage (BDV). The tests are carried out at diff erent concentration of nanofi llers with the mass fractions of 0.01, 0.05 and 0.1. Statistical analysis of test data is performed using two parameter Weibull distribution and the results are compared with and without CQD treatment. Results are also compared with conventional mineral oil. Addition of CQD treated insulative SiO 2 nanofi llers show good insulation performance than semiconductive TiO 2 nanofi llers. The overall results clearly indicate the positive infl uence of CQD treatment on SiO 2 /TiO 2 nanoparticles at lower %wt (0.01%wt) concentration of nanofi llers and clearly show the suitability for MV transformer insulation applications.

Evolution of Agrometeorology at the Global Level

Sivakumar, M.V.K. 한국농림기상학회 2004 한국농림기상학회지 Vol.6 No.2

농업기상은 지난 100년동안 서술적인 학문에서 물리학적 및 생물학적 법칙을 활용하는 정량적인 학문적으로 발전되어 왔다. 농업인들은 기후와 기상정보의 이용으로 수익을 개선할 수 있다는 점을 더욱 깊이 인식하게 되었고, 이는 농업기상서비스에 대한 수요를 증대로 이어질 것이라는 점은 의심할 여지가 없다. 그러므로 21세기 농업기상의 필요성과 전망을 크게 두 가지 주제로 구분하는 것은 시의 적절하다 할 수 있다. 즉 농업생산을 위한 농업기상서비스와 이들 서비스를 지원하기 위한 농업기상자원시스템의 중요한 구성요소인 자료, 연구, 정책 및 훈련/교육/지도의 중요성이 더욱 강조될 것이다. 몬티쓰박사가 말한 바와 같이, 식량공급은 궁극적으로 기상자원의 잠재성을 탐구하거나 악기상의 영향을 최소화하는 농민의 기술력에 좌우될 것이다. 장비, 자료관리체계, 기후예측, 작물모의, 농업기상정보 배분등에 있어서의 최근 발전으로 인해 농민이 이러한 핵심기술을 습득, 향상시키는 것을 돕기 위해 필요한 도구들이 농업기상학자들에게 제공되고 있다. 따라서 향후 농업기상기술의 현장활용은 그 전도가 매우 밝다 하겠으며, 이러한 기술의 현장활용을 통해 지속농업의 촉진 및 빈곤타파 등에 농업기상이 근원적인 커다란 기여를 할 수 있을 것이다. Agricultural meteorology has advanced during the last 100 years from a descriptive to a quantitative science using physical and biological principles. The agricultural community is becoming more aware that using climate and weather information will improve their profitability and this will no doubt increase the demand for agrometeorological services. Hence it is timely that the needs and perspectives for agrometeorology in the 21^(st) Century are grouped under two major headings: agrometeorological services for agricultural production and agrometeorological support systems for such services. Emphasis must be placed on the components of such support systems comprising of data, research, policies and training/ education/extension. As Monteith (2000) mentioned, food supplies ultimately depend upon the skill with which farmers can exploit the potential of good weather and minimize the impact of bad weather: Recent developments in instrumentation, data management systems, climate prediction, crop modelling, dissemination of agrometeorological information etc., provide agrometeorologicts the tools necessary help the farmers improve such skills. The future for operational applications of agricultural meteorology appears bright and such applications could contribute substantially to promote sustainable agriculture and alleviate poverty.

PERFORMANCE EVALUATION OF ON - SITE WASTE TREATMENT SYSTEMS USED BY REMOTE AND RURAL COMMUNITIES OF AUSTRALIA

( M . A . Khalife,H . B . Dharmappa,M . Sivakumar ) 한국물환경학회 1997 제6차 국제수질보전학회 아시아 태평양지역 학술회의 Vol.2 No.-

Synthesis of Carbon Molecular Sieve from Palm Shell Using Deposition of Polyfurfuryl Alcohol

Sivakumar, V.M.,Lam, Kok-Keong,Mohamed, Abdul Rahman Korean Chemical Society 2010 대한화학회지 Vol.54 No.3

이 연구에서는 야자껍질로부터 이상적인 sieving 특성을 갖는 탄소 분자 체(CMS)의 합성을 시도하였다. 그 과정은 세 단계로 이루어지는데 탄소화 과정, 이산화 탄소 활성화 과정, 그리고 polyfurfuryl 알코올 고분자 증착 과정이다. 이산화 탄소 활성화에 의해 야자 껍질로부터 만들어진 활성탄(CA)은 CMS의 합성을 위한 원료 물질로 사용되었다. 야자껍질로부터 만들어진 AC를 준비한 다음 AC에 대한 최적의 furfuryl 알코올 과 포름 알데히드 비를 결정하였다. AC에 polyfurfuryl 알코올의 증착을 탄소화 과정에 앞서 수행하였다. 이렇게 고분자가 증착된 AC는 불활성 환경 조건과 $700-900^{\circ}C$온도에서 탄소화 과정을 거친다. 모든 미세세공 물질은 micrometric사의 ASAP/2020을 이용하여 분석되었다. 결과로 AC에 대한 최적의 furfuryl 알코올 과 포름 알데히드 비는 1:2.5로 결정 되었다. 7 ${\AA}$ 이하의 미세세공은 $700^{\circ}C$, $800^{\circ}C$ 그리고 $900^{\circ}C$ 에서 1.5시간 동안 고분자가 증착된 AC에 형성 되었다. 1.5시간 동안 $900^{\circ}C$ 에서 탄소화 온도는 CMS합성을 위한 최적의 조건으로 밝혀졌다. 이러한 조건하에서 생성된 CMS는 5. 884 ${\AA}$의 구멍 크기를 갖는다. In this work, an intention to synthesize the carbon molecular sieve (CMS) with ideal sieving properties from palm shell has been attempted. The process includes three main stages: carbonization, carbon dioxide activation and polymer deposition using polyfurfuryl alcohols. Palm shell based activated carbon (AC) produced by carbon dioxide activation was used as raw material in synthesis of CMS. After preparing palm shell based AC, optimum concentration ratio of furfuryl alcohols and formaldehyde to AC for CMS synthesis was obtained in this study. Deposition of polyfurfuryl alcohols on the palm shell based AC was then carried out prior to carbonization. These polymer deposited AC was subjected to carbonization at $700-900^{\circ}C$ under inert condition. All the microporous materials were analyzed using micromeritics ASAP/2020. The results show that optimum concentration ratio of furfuryl alcohol and formaldehyde to AC is 1:2.5. The micropore with pore width less than 7 ${\AA}$ was formed on the polymer deposited AC at $700^{\circ}C$, $800^{\circ}C$ and $900^{\circ}C$ for 1.5 hours. Carbonization temperature at $900^{\circ}C$ for 1.5 hours was found to be optimum for CMS synthesis. The CMS produced under this condition has pore width of 5.884 ${\AA}$.

Antitumor and antioxidant activities of Bryonia laciniosa against Ehrlich's Ascites Carcinoma bearing Swiss albino mice

Sivakumar, T,Kumar, R Sambath,Perumal, P,Vamsi, MLM,Sivakumar, P,Kanagasabai, R,Baskaran, MV,Karki, Subhas S,Mazumder, UK,Gupta, M Kyung Hee Oriental Medicine Research Center 2005 Oriental pharmacy and experimental medicine Vol.5 No.4

The plant Bryonia laciniosa (Family: Cucurbitaceae) has been indicated for the treatment of various diseases one among which is cancer. The purpose of this study was investigating experimentally the possible anti-tumor effect and antioxidant role of Bryonia laciniosa leaves in animal model. The methanol extract of Bryonia laciniosa (MEBL) administered at the doses of 62.5, 125 and 250 mg/kg in mice for 14 days after 24 h of tumor inoculation. The effect of MEBL on the growth of transplantable murine tumor, life span of EAC bearing mice, hematological profile and liver biochemical parameters (lipid peroxidation, antioxidant enzymes) were estimated. Treatment with MEBL decreased the tumor volume and viable cell count thereby increasing the life span of EAC bearing mice and brought back the hematological parameter more or less normal level. The effect of MEBL also decreases the levels of lipid peroxidation and increased the levels of glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT). The present work indicates that the methanol extract of Bryonia laciniosa exhibited significant antitumor and antioxidant activity in vivo.

Evolution of Agrometeorology at the Global Level

( M. V. K. Sivakumar ) 한국농림기상학회 2003 학술발표논문집 Vol.2003 No.1

Aspect-based Sentiment Analysis of Product Reviews using Multi-agent Deep Reinforcement Learning

M. Sivakumar,Srinivasulu Reddy Uyyala 한국경영정보학회 2022 Asia Pacific Journal of Information Systems Vol.32 No.2

The existing model for sentiment analysis of product reviews learned from past data and new data was labeled based on training. But new data was never used by the existing system for making a decision. The proposed Aspect-based multi-agent Deep Reinforcement learning Sentiment Analysis (ADRSA) model learned from its very first data without the help of any training dataset and labeled a sentence with aspect category and sentiment polarity. It keeps on learning from the new data and updates its knowledge for improving its intelligence. The decision of the proposed system changed over time based on the new data. So, the accuracy of the sentiment analysis using deep reinforcement learning was improved over supervised learning and unsupervised learning methods. Hence, the sentiments of premium customers on a particular site can be explored to other customers effectively. A dynamic environment with a strong knowledge base can help the system to remember the sentences and usage State Action Reward State Action (SARSA) algorithm with Bidirectional Encoder Representations from Transformers (BERT) model improved the performance of the proposed system in terms of accuracy when compared to the state of art methods.