Benchmarking of Zinc Coatings for Corrosion Protection: A Detailed Characterization of Corrosion and Electrochemical Properties of Zinc Coatings

( Sudesh L Wijesinghe ),( Tan Zixi ) 한국부식방식학회(구 한국부식학회) 2017 Corrosion Science and Technology Vol.16 No.1

Due to various types of Zn coatings for many decades for various applications, it is imperative to study and compare their corrosion resistance properties of some of these. Here, we introduce a systematic methodology for evaluation and validation of corrosion protection properties of metallic coatings. According to this methodology, samples are were exposed in an advanced cyclic corrosion test chamber according to ISO 14993, and removed at the end of each withdrawal for respective corrosion and electrochemical characterization to evaluate both barrier and galvanic protection properties. Corrosion protection properties of coatings were evaluated by visual examination according to ISO 10289, mass loss and subsequent corrosion rate measurements, electrochemical properties, and advanced electrochemical scanning techniques. In this study, corrosion protection properties of a commercial zinc rich coating (ZRC) on AISI 1020 mild steel substrates were evaluated and benchmarked against hot dip galvanized (HDG). Results were correlated, and corrosion protection capabilities of the two coatings were compared. The zinc rich coating performed better than hot dip galvanized coating in terms of overall corrosion protection properties, according to the exposure and experimental conditions used in this study. It proved to be a suitable candidate to replace hot dip galvanized coatings for desired applications.

Effect of Tropical Atmosphere on Corrosion of Different Metals

( Sudesh Wijesinghe ),( Tan Zixi ) 한국부식방식학회(구 한국부식학회) 2017 Corrosion Science and Technology Vol.16 No.6

Atmospheric corrosion is clearly the most noticeable of all corrosion processes. A tremendous amount of economic losses are caused by atmospheric corrosion. Thus, it is imperative to know the level of atmosphere’s aggressiveness or in other words “corrosivity”, before designing or planning any corrosion prevention strategy. In Singapore, corrosivity values were not recorded earlier though the process of measurement and recording was prevalent in other countries. With an aim of filling this gap, three test sites were setup at three locations in Singapore to represent marine, industrial and urban atmospheres or their mixtures. Subsequently, corrosivity readings were measured and recorded according to ISO 9223:2012 for the first time in Singapore. Salient atmospheric constituents or parameters like time of wetness (TOW), Cl^-, SO₂, NO₂, O₃, and HNO₃ were measured at all sites over a period of time to categorize corrosivity of particular atmosphere. The effect of the atmosphere on corrosion of steel, Cu, Al, and Zn has also been investigated and quantified. “Estimated” and “determined” corrosivities were quantified and compared according to ISO 9223 standard. The study data along with final corrosivity measurements will be presented and discussed in the present work.

IS EXPORT-LED INDUSTRIAL DEVELOPMENT A VIABLE POLICY? SOME EMPIRICAL EVIDENCE

Sudesh Mujumdar,Jeffrey A Mills,Peter Cashel Cordo People&Global Business Association 2005 Global Business and Finance Review Vol.10 No.1

This paper re-examines the time-series evidence on the relationship between exports and industrial development for eight newly-industrialized economies in light of recent breakthroughs in time-series analysis. Specifically, the investigation employs the time-series procedure of Toda and Yamamoto (1995) where many shortcomings of the traditional approaches (e.g., the Vector-Error-Correction approach) are overcome. The investigation reveals that for all but one of the economies where a policy of export-led growth was explicitly adopted, there is evidence indicating that current increases in exports produce future increases in industrial output. Such evidence is not found for the economies where the policy was not explicitly adopted. This suggests that for a country without an explicit strategy of export-expansion, it appears unlikely that export-expansion will spontaneously stimulate industrial development.

Strategic Trade Policy with Generalized Social Welfare Functions

Sudesh Mujumdar,Mark D.White 사람과세계경영학회 2012 Global Business and Finance Review Vol.17 No.1

This paper investigates the conduct of strategic trade policy when the government maximizes a generalized social welfare function with variable weights on profit and consumer surplus. We find the unexpected result that increased emphasis on either will tend to favor the use of the subsidy rather than the tariff.

Selenium- and Tellurium-Containing Fluorescent Molecular Probes for the Detection of Biologically Important Analytes

Manjare, Sudesh T.,Kim, Youngsam,Churchill, David G. American Chemical Society 2014 Accounts of chemical research Vol.47 No.10

<title>Conspectus</title><P>As scientists in recent decades have discovered, selenium is an important trace element in life. The element is now known to play an important role in biology as an enzymatic antioxidant. In this case, it sits at the active site and converts biological hydrogen peroxides to water. Mimicking this reaction, chemists have synthesized several organoselenium compounds that undergo redox transformations. As such, these types of compounds are important in the future of both medicinal and materials chemistry. One main challenge for organochalcogen chemists has been to synthesize molecular probes that are soluble in water where a selenium or tellurium center can best modify electronics of the molecule based on a chemical oxidation or reduction event.</P><P>In this Account, we discuss chemists’ recent efforts to create chalcogen-based chemosensors through synthetic means and current photophysical understanding. Our work has focused on small chromophoric or fluorophoric molecules, in which we incorporate discrete organochalcogen atoms (e.g., R-Se-R, R-Te-R) in predesigned sites. These synthetic molecules, involving rational synthetic pathways, allow us to chemoselectively oxidize compounds and to study the level of analyte selectivity by way of their optical responses. All the reports we discussed here deal with <I>well-defined and small synthetic</I> molecular systems.</P><P>With a large number of reports published over the last few years, many have notably originated from the laboratory of K. Han (P. R. China). This growing body of research has given chemists new ideas for the previously untenable reversible reactive oxygen species detection. While reversibility of the probe is technically important from the stand-point of the chalcogen center, facile regenerability of the probe using a secondary analyte to recover the initial probe is a very promising avenue. This is because (bio)chalcogen chemistry is extremely rich and bioinspired and continues to yield important developments across many scientific fields. Organochalcogen (R-E-R) chemistry in such chemical recognition and supramolecular pursuits is a fundamental tool to allow chemists to explore stable organic-based probe modalities of interest to develop better spectroscopic tools for (neuro)biological applications.</P><P>Chalcogen donor sites also provide sites where metals can coordinate, and facile oxidation may extend to the sulfone analogues (R-EO<SUB>2</SUB>-R) or beyond. Consequently, chemists can then make use of reliable reversible chemical probing platforms based on the chemical redox properties valence state switching principally from 2 to 4 (and back to 2) of selenium and tellurium atoms. The main organic molecular skeletons have involved chemical frames including boron-dipyrromethene (BODIPY) systems, extended cyanine groups, naphthalimide, rhodamine, and fluorescein cores, and isoselenazolone, pyrene, coumarin, benzoselenadiazole, and selenoguanine systems.</P><P>Our group has tested many such molecular probe systems in cellular milieu and under a series of conditions and competitive environments. We have found that the most important analytes have been reactive oxygen species (ROS) such as superoxide and hypochlorite. Reactive nitrogen species (RNS) such as peroxynitrite are also potential targets. In addition, we have also considered Fenton chemistry systems. Our research and that of others shows that the action of ROS is often reversible with H<SUB>2</SUB>S or biothiols such as glutathione (GSH).</P><P>We have also found that a second class of analytes are the thiols (RSH), in particular, biothiols. Here, the target group might involve an R-Se-Se-R group. The study of analytes also extends to metal ions, for example, Hg<SUP>2+</SUP>, and anions such as fluoride (F<SUP>–</SUP>), and we have developed NIR-based systems as well. These work through various photomechanisms, including photoinduced electron transfer (PET), twisted i

Thermo-electrical properties of randomly oriented carbon/carbon composite

Thakur Sudesh Kumar Raunija,N. Supriya 한국탄소학회 2017 Carbon Letters Vol.22 No.-

The aim of the work was to investigate the thermo-electrical properties of low cost and rapidly produced randomly oriented carbon/carbon (C/C) composite. The composite body was fabricated by combining the high-pressure hot-pressing (HP) method with the lowpressure impregnation thermosetting carbonization (ITC) method. After the ITC method step selected samples were graphitized at 3000°C. Detailed characterization of the samples’ physical properties and thermal properties, including thermal diffusivity, thermal conductivity, specific heat and coefficient of thermal expansion, was carried out. Additionally, direct current (DC) electrical conductivity in both the in-plane and through-plane directions was evaluated. The results indicated that after graphitization the specimens had excellent carbon purity (99.9 %) as compared to that after carbonization (98.1). The results further showed an increasing trend in thermal conductivity with temperature for the carbonized samples and a decreasing trend in thermal conductivity with temperature for graphitized samples. The influence of the thickness of the test specimen on the thermal conductivity was found to be negligible. Further, all of the specimens after graphitization displayed an enormous increase in electrical conductivity (from 190 to 565 and 595 to 1180 S/cm in the through-plane and in-plane directions, respectively).

Facile <i>meso</i>-BODIPY Annulation and Selective Sensing of Hypochlorite in Water

Manjare, Sudesh T.,Kim, Jin,Lee, Yunho,Churchill, David G. American Chemical Society 2014 Organic letters Vol.16 No.2

<P>Annulated BODIPY chalcogenide (Se, Te) systems were synthesized from their respective bis(<I>o</I>-formylphenyl)dichalcogenide intermediates. The annulated BODIPY selenide product was confirmed by X-ray diffraction. The red-shifted telluride version was found to be sensitive and selective for hypochlorite detection, reversible upon treatment with biothiols.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/orlef7/2014/orlef7.2014.16.issue-2/ol403405n/production/images/medium/ol-2013-03405n_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ol403405n'>ACS Electronic Supporting Info</A></P>

Influence of hot-pressing pressure on the densification of short-carbon-fiber-reinforced, randomly oriented carbon/ carbon composite

Thakur Sudesh Kumar Raunija,Sharad Chandra Sharma 한국탄소학회 2015 Carbon Letters Vol.16 No.1

The prime objective of this research was to study the influence of hot-pressing pressure and matrix-to-reinforcement ratio on the densification of short-carbon-fiber-reinforced, randomly oriented carbon/carbon-composite. Secondary objectives included determination of the physical and mechanical properties of the resulting composite. The ‘hybrid carbon-fiberreinforced mesophase-pitch-derived carbon-matrix’ composite was fabricated by hot pressing. During hot pressing, pressure was varied from 5 to 20 MPa, and reinforcement wt% from 30 to 70. Densification of all the compacts was carried at low impregnation pressure with phenolic resin. The effect of the impregnation cycles was determined using measurements of microstructure and density. The results showed that effective densification strongly depended on the hot-pressing pressure and reinforcement wt%. Furthermore, results showed that compacts processed at lower hot-pressing pressure, and at higher reinforcement wt%, gained density gradually during three densification cycles and showed the symptoms of further gains with additional densification cycles. In contrast, samples that were hot-pressed at moderate pressure and at moderate reinforcement wt%, achieved maximum density within three densification cycles. Furthermore, examination of microstructure revealed the formation of cracks in samples processed at lower pressure and with low reinforcement wt%.

Selective and Sensitive Superoxide Detection with a New <i>Diselenide</i>-Based Molecular Probe in Living Breast Cancer Cells

Manjare, Sudesh T.,Kim, Sungsoo,Heo, Won Do,Churchill, David G. American Chemical Society 2014 Organic letters Vol.16 No.2

<P>A diselenide-based BODIPY probe was prepared; it was found to be sensitive and selective for superoxide in giving [-Se(O)Se(O)-] oxidation. Probing was reversible through the use of biothiols; <SUP>77</SUP>Se NMR and other types of spectroscopy were employed. Practical medicinal utility was demonstrated in MCF-7/ADR cancer cells.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/orlef7/2014/orlef7.2014.16.issue-2/ol4033013/production/images/medium/ol-2013-033013_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ol4033013'>ACS Electronic Supporting Info</A></P>

Regional Comprehensive Economic Partnership (RCEP) FTA

Rajan Sudesh Ratna,Jing Huang 한국경제연구학회 2016 Korea and the World Economy Vol.17 No.2

The Regional Comprehensive Economic Partnership (RCEP) is an ASEAN-led proposal for a regional free trade area between 10 ASEAN countries and ASEAN’s 6 other Free Trade Agreement (FTA) partners. The current international trade regime is now being governed by the non-tariff measures that raise the trade cost. The critical issue for market access, thus, would be as to how the reduction/elimination of non-tariff measures (NTMs) is addressed in RCEP negotiations. This paper first explores the background of RCEP, the trade and tariff profiles of RCEP members. The paper examines the overall trade cost using the ESCAP — World Bank database and then evaluates the impact of elimination of non-tariff related trade cost on intra-RCEP exports in a post FTA situation by using the gravity model. Lastly, this paper suggests some measures for effective RCEP negotiations, especially how to deal with the issues relating to non-tariff measures with a special focus on sanitary and phytosanitary, and technical barriers to trade.