2,4-Dimethoxy-2,4-dimethylpentan-3-one: An Aprotic Solvent Designed for Stability in Li–O₂ Cells

Sharon, Daniel,Sharon, Pessia,Hirshberg, Daniel,Salama, Michael,Afri, Michal,Shimon, Linda J. W.,Kwak, Won-Jin,Sun, Yang-Kook,Frimer, Aryeh A.,Aurbach, Doron American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.34

<P>In this study, we present a new aprotic solvent, 2,4-dimethoxy-2,4-dimethylpentan-3-one (DMDMP), which is designed to resist nucleophilic attack and hydrogen abstraction by reduced oxygen species. Li-O-2 cells using DMDMP solutions were successfully cycled. By various analytical measurements, we showed that even after prolonged cycling only a negligible amount of DMDMP was degraded. We suggest that the observed capacity fading of the Li-O-2 DMDMP-based cells was due to instability of the lithium anode during cycling. The stability toward oxygen species makes DMDMP an excellent solvent candidate for many kinds of electrochemical systems which involve oxygen reduction and assorted evaluation reactions.</P>

Photocatalytic Degradation of E. coli and S. aureus by Multi Walled Carbon Nanotubes

Sharon, Madhuri,Datta, Suprama,Shah, Sejal,Sharon, Mahesh War,Soga, T.,Afre, Rakesh Korean Carbon Society 2007 Carbon Letters Vol.8 No.3

Carbon Nano Tubes could be either metallic or semi-conducting in nature, depending on their diameter. Its photocatalytic behavior has given an impetus to use it as an anti-microbial agent. More than 95% Escherichia coli and Staphylococcus aureus bacteria got killed when exposed to Carbon Nano Tubes for 30 minutes in presence of sunlight. Carbon Nano Tubes are supposed to have smooth surface on to which it accumulates positive charges when exposed to light. The surface that is non illuminated has negative charge. At the cellular level microorganisms produce negative charges on the cell membrane, Therefore damaging effect of multi walled carbon nano tubes (exposed to light) on the microorganisms is possible. In this paper, photo catalytic killing of microbes by multi walled carbon nano tubes is reported. Killing was due to damage in the cell membrane, as seen in SEM micrographs. Moreover biochemical analysis of membrane as well as total cellular proteins by SDS PAGE showed that there was denaturation of membrane proteins as well as total proteins of both the microbes studied. The killed microbes that showed a decrease in number of protein bands (i.e. due to breaking down of proteins) also showed an increase in level of free amino acids in microbes. This further confirmed that proteins got denatured or broken down into shorter units of amino acids. Increased level of free amino acids was recorded in both the microbes treated with multi walled carbon nano tubes and sunlight.

Special Theme 02 - NFPA의 화재안전교육 전략

Gamache, Sharon 한국화재보험협회 2011 防災와 保險 Vol.143 No.-

Sharon Gamache는 National Safety Council, NFPA에 근무하면서 대민화재안전교육 업무를 수행하여 왔다. NFPA의 High-Risk Outreach 프로그램을 총괄하며 다수의 대민화재안전교육 교재 제작을 지휘하였다.

Platinum nanocomposites and its applications: A review

Sharon, Madhuri,Nandgavkar, Isaac,Sharon, Maheshwar Techno-Press 2017 Advances in materials research Vol.6 No.2

Platinum is a transition metal that is very resistant to corrosion. It is used as catalyst for converting methyl alcohol to formaldehyde, as catalytic converter in cars, for hydrocracking of heavy oils, in Fuel Cell devices etc. Moreover, Platinum compounds are important ingredient for cancer chemotherapy drugs. The nano forms of Platinum due to its unique physico-chemical properties that are not found in its bulk counterpart, has been found to be of great importance in electronics, optoelectronics, enzyme immobilization etc. The stability of Platinum nanoparticles has supported its use for the development of efficient and durable proton exchange membrane Fuel Cells. The present review concentrates on the use of Platinum conjugated with various metal or compounds, to fabricate nanocomposites, to enhance the efficiency of Platinum nanoparticles. The recent advances in the synthesis methods of different Platinum-based nanocomposites and their applications in Fuel Cell, sensors, bioimaging, light emitting diode, dye sensitized solar cell, hydrogen generation and in biosystems has also been discussed.

Hydrogen Storage by Carbon Fibers Synthesized by Pyrolysis of Cotton Fibers

Maheshwar Sharon,Madhuri Sharon,Golap Kalita,Bholanath Mukherjee 한국탄소학회 2011 Carbon Letters Vol.12 No.1

Synthesis of carbon fibers from cotton fiber by pyrolysis process has been described. Synthesis parameters are optimized using Taguchi optimization technique. Synthesized carbon fibers are used for studying hydrogen adsorption capacity using Seivert's apparatus. Transmission electron microscopy analysis and X-ray diffraction of carbon fiber from cotton suggested it to be very transparent type material possessing graphitic nature. Carbon synthesized from cotton fibers under the conditions predicted by Taguchi optimization methodology (no treatment of cotton fiber prior to pyrolysis, temperature of pyrolysis 800℃, Argon as carrier gas and paralyzing time for 2 h) exhibited 7.32 wt% hydrogen adsorption capacity.

Photocatalytic Degradation of E. coli and S. aureus by Multi Walled Carbon Nanotubes

Madhuri Sharon,Suprama Datta,Sejal Shah,Mahesh War Sharon,T. Soga,Rakesh Afre 한국탄소학회 2007 Carbon Letters Vol.8 No.3

Carbon Nano Tubes could be either metallic or semi-conducting in nature, depending on their diameter. Its photocatalytic behavior has given an impetus to use it as an anti-microbial agent. More than 95% Escherichia coli and Staphylococcus aureus bacteria got killed when exposed to Carbon Nano Tubes for 30 minutes in presence of sunlight. Carbon Nano Tubes are supposed to have smooth surface on to which it accumulates positive charges when exposed to light. The surface that is non illuminated has negative charge. At the cellular level microorganisms produce negative charges on the cell membrane, Therefore damaging effect of multi walled carbon nano tubes (exposed to light) on the microorganisms is possible. In this paper, photo catalytic killing of microbes by multi walled carbon nano tubes is reported. Killing was due to damage in the cell membrane, as seen in SEM micrographs. Moreover biochemical analysis of membrane as well as total cellular proteins by SDS PAGE showed that there was denaturation of membrane proteins as well as total proteins of both the microbes studied. The killed microbes that showed a decrease in number of protein bands (i.e. due to breaking down of proteins) also showed an increase in level of free amino acids in microbes. This further confirmed that proteins got denatured or broken down into shorter units of amino acids. Increased level of free amino acids was recorded in both the microbes treated with multi walled carbon nano tubes and sunlight.

Effect of Inherent Anatomy of Plant Fibers on the Morphology of Carbon Synthesized from Them and Their Hydrogen Absorption Capacity

Madhuri Sharon,Maheshwar Sharon 한국탄소학회 2012 Carbon Letters Vol.13 No.3

Carbon materials were synthesized by pyrolysis from fibers of Corn-straw (Zea mays), Rice-straw (Oryza sativa), Jute-straw (Corchorus capsularis) Bamboo (Bombax bambusa), Bagass (Saccharum officinarum), Cotton (Bombax malabaricum), and Coconut (Cocos nucifera); these materials were characterized by scanning electron microscope, X-ray diffraction (XRD), and Raman spectra. All carbon materials are micro sized with large pores or channel like morphology. The unique complex spongy, porous and channel like structure of Carbon shows a lot of similarity with the original anatomy of the plant fibers used as precursor. Waxy contents like tyloses and pits present on fiber tracheids that were seen in the inherent anatomy disappear after pyrolysis and only the carbon skeleton remained; XRD analysis shows that carbon shows the development of a (002) plane, with the exception of carbon obtained from bamboo, which shows a very crystalline character. Raman studies of all carbon materials showed the presence of G- and D-bands of almost equal intensities, suggesting the presence of graphitic carbon as well as a disordered graphitic structure. Carbon materials possessing lesser density, larger surface area, more graphitic with less of an sp3 carbon contribution, and having pore sizes around 10μm favor hydrogen adsorption. Carbon materials synthesized from bagass meet these requirements most effectively, followed by cotton fiber, which was more effective than the carbon synthesized from the other plant fibers.

Depicting Southern Honor in Maria Jane Mclntosh`s Two Pictures; or, What We Think of Ourselves and What the World Thinks of Us

Sharon Talley 19세기영어권문학회 2014 19세기 영어권 문학 Vol.18 No.2

This essay provides a critical introduction to Maria Jane McIntosh`s novel Two Pictures; or, What We Think of Ourselves and What the World Thinks of Us. Published in the midst of the United States Civil War, this novel takes a strongly regional stance to frame the political issues and ideologies related to the war and southern society`s patriarchal structure in established literary contexts and a familiar narrative structure. As a result, when it was published, it appealed to a popular readership that was anxious to defend itself and retain faith in the possibility of cultural and social continuity. By recovering and reading Two Pictures today we can enrich our understanding of the time period and the role that such literature played in the ultimately unsuccessful effort to validate and sustain the Old South`s distinctive socioeconomic and cultural identity.

Colorless Racialization: Analyzing the Discrimination of ‘Oldcomer’ Koreans in Japan and Chinese in Korea from an American Sociological Perspective

Sharon Yoon 한국사회학회 2016 韓國社會學 Vol.50 No.6

Past sociological theories on race and ethnicity have attributed the persistence of racial discrimination to physical, and presumably immutable, features of racial identification. Thus, despite the decline of institutional forms of racism, scholars have pointed to enduring patterns of marginalization among racially distinct minorities in a variety of different measures. This paper finds that contrary to theories which purport to predict a decline in racial discrimination with the increasing physical indistinguishability of minorities, culturally assimilated Korean minorities in Japan and Chinese minorities in Korea continue to experience marginalization due to nationality laws that exclude on the basis of ancestry as opposed to place of residence or birth. The paper proposes that rather than physical markers of race, legal and societal definitions of in-group membership and nationhood play more definitive roles in perpetuating the discrimination of minorities in society.

Fixed Book Price (FBP) System in Korea

( Sharon Smith ),( Taeyoung Kwon ) 서암순창장학회 2017 Journal of Marketing Thought Vol.4 No.1

A fixed book price (FBP) system is a mechanism to fix the price at which books are sold to the public. In South Korea, the advantages and disadvantages of a fixed book price are more hotly debated than ever before. The major reform of FBP legislation in November 2014 resulted in profound changes to Korean publishers and retailers. In this article, we analyze the performance and emerging issues of the FBP systems with a focus on bookstores (on-offline) and publishers (on-offline). Finally, we propose improvements to the FBP in Korea.