Effect of pressure on the corrosion and carburization behavior of chromia-forming heat-resistant alloys in high-temperature carbon dioxide environments

Lee, H.J.,Subramanian, G.O.,Kim, S.H.,Jang, C. Pergamon Press 2016 Corrosion science Vol.111 No.-

Chromia-forming heat-resistant alloys were corroded in atmospheric CO<SUB>2</SUB> (0.1MPa) and supercritical-CO<SUB>2</SUB> (S-CO<SUB>2</SUB>, 10 and 20MPa) at 550-650<SUP>o</SUP>C for 1000h. The weight gain and the extent of an amorphous C layer at the oxide/matrix interface increased with increasing CO<SUB>2</SUB> pressure from 0.1MPa to 20MPa, but the increase was mostly less than a factor of 2. Despite the huge difference in the test pressure, the depth of the carburized region with Cr-rich carbides was rarely affected for Alloy 800HT, resulting in similar tensile properties after corrosion in CO<SUB>2</SUB> and S-CO<SUB>2</SUB>.

MODEL-BASED ANALYSIS OF THE MECHANICAL SUBSYSTEM OF AN AIR BRAKE SYSTEM

D. B. SONAWANE,K. NARAYAN,V. S. RAO,S. C. SUBRAMANIAN 한국자동차공학회 2011 International journal of automotive technology Vol.12 No.5

Most commercial vehicles such as buses and trucks use an air brake system, often equipped with an S-cam drum brake, to reduce their speed and/or to stop. With a drum brake system, the clearance between the brake shoe/pad and the brake drum may increase because of various reasons such as wearing of the brake shoe and/or brake drum and drum expansion caused by high heat generation during the braking process. Hence, to ensure proper functioning of the brake system, it is essential that the clearance between the brake shoe and the brake drum is monitored. In this paper, we present a mathematical model for the mechanical subsystem of the air brake system that can be used to monitor this clearance. This mathematical model correlates the push rod stroke transients and the brake chamber pressure transients. A kinematic analysis and a dynamic analysis of the mechanical subsystem of the air brake system were performed, and the results are corroborated with experimental data.

Simple replication methods for producing nanoslits in thermoplastics and the transport dynamics of double-stranded DNA through these slits

Chantiwas, Rattikan,Hupert, Mateusz L.,Pullagurla, Swathi R.,Balamurugan, Subramanian,Tamarit-Ló,pez, Jesú,s,Park, Sunggook,Datta, Proyag,Goettert, Jost,Cho, Yoon-Kyoung,Soper, Steven A. Royal Society of Chemistry 2010 Lab on a chip Vol.10 No.23

<P>Mixed-scale nano- and microfluidic networks were fabricated in thermoplastics using simple and robust methods that did not require the use of sophisticated equipment to produce the nanostructures. High-precision micromilling (HPMM) and photolithography were used to generate mixed-scale molding tools that were subsequently used for producing fluidic networks into thermoplastics such as poly(methyl methacrylate), PMMA, cyclic olefin copolymer, COC, and polycarbonate, PC. Nanoslit arrays were imprinted into the polymer using a nanoimprinting tool, which was composed of an optical mask with patterns that were 2–7 µm in width and a depth defined by the Cr layer (100 nm), which was deposited onto glass. The device also contained a microchannel network that was hot embossed into the polymer substrate using a metal molding tool prepared <I>via</I> HPMM. The mixed-scale device could also be used as a master to produce a polymer stamp, which was made from polydimethylsiloxane, PDMS, and used to generate the mixed-scale fluidic network in a single step. Thermal fusion bonding of the cover plate to the substrate at a temperature below their respective <I>T</I><SUB>g</SUB> was accomplished by oxygen plasma treatment of both the substrate and cover plate, which significantly reduced thermally induced structural deformation during assembly: ∼6% for PMMA and ∼9% for COC nanoslits. The electrokinetic transport properties of double-stranded DNA (dsDNA) through the polymeric nanoslits (PMMA and COC) were carried out. In these polymer devices, the dsDNA demonstrated a field-dependent electrophoretic mobility with intermittent transport dynamics. DNA mobilities were found to be 8.2 ± 0.7 × 10<SUP>−4</SUP> cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> and 7.6 ± 0.6 × 10<SUP>−4</SUP> cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> for PMMA and COC, respectively, at a field strength of 25 V cm<SUP>−1</SUP>. The extension factors for λ-DNA were 0.46 in PMMA and 0.53 in COC for the nanoslits (2–6% standard deviation).</P> <P>Graphic Abstract</P><P>Thermoplastic nanoslits were replicated from a simple molding tool and consisted of mixed-scale structures with successful DNA translocation through the slits demonstrated. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0lc00096e'> </P>

Nanospheres and nanorods structured Fe₂O₃ and Fe_2-xGa_xO₃ photocatalysts for visible-light mediated (λ>=420nm) H₂S decomposition and H₂ generation

Subramanian, E.,Baeg, J.O.,Lee, S.M.,Moon, S.J.,Kong, K.j. Pergamon Press ; Elsevier Science Ltd 2009 International journal of hydrogen energy Vol.34 No.20

This article reports our investigation on H<SUB>2</SUB> generation from visible light (λ>=420nm) photodecomposition of H<SUB>2</SUB>S by nanomaterial catalysts, α-Fe<SUB>2</SUB>O<SUB>3</SUB> and its chemically modified Fe<SUB>2-x</SUB>Ga<SUB>x</SUB>O<SUB>3</SUB> (Ga substitution at x=0.6, FeGaO<SUB>3</SUB>-I and x=1.0, FeGaO<SUB>3</SUB>-II). Simple template-free hydrothermal technique was employed to synthesize the three photocatalysts. XRD study reveals rhombohedral nanocrystalline structure and FESEM shows nanospheres morphology for Fe<SUB>2</SUB>O<SUB>3</SUB> and nanosticks/nanorods for both FeGaO<SUB>3</SUB>-I, and FeGaO<SUB>3</SUB>-II. In H<SUB>2</SUB> generation, Fe<SUB>2</SUB>O<SUB>3</SUB> and FeGaO<SUB>3</SUB>-II perform moderate and almost same activities in the fresh and used conditions (quantum yield, QY=6.0-6.8% at 550nm). Contrarily, fresh FeGaO<SUB>3</SUB>-I exhibits a greater activity (11.2% QY) and the activity is further enhanced (QY=15.3%) on regeneration and reuse. The intricacy, as resolved by XRD and FESEM, appears to take place through morphology transformation. The present work, thus, successfully demonstrates H<SUB>2</SUB> generation from H<SUB>2</SUB>S by nanostructured photocatalysts involving morphology dependent activity enhancement.

DESIGN AND DEVELOPMENT OF A HEADING ANGLE CONTROLLER FOR AN UNMANNED GROUND VEHICLE

S. SAHOO,S. C. SUBRAMANIAN,N. MAHALE,S. SRIVASTAVA 한국자동차공학회 2015 International journal of automotive technology Vol.16 No.1

This paper describes the design and implementation of a controller to track the desired heading angle for an unmanned ground vehicle (UGV) considering the limits on rotation of steering wheel and steering motor rate. The well-known “bicycle model” approximation, that considers the vehicle slip angle and ground-wheel interaction, has been used. In this work, combined closed loop control for steering motor and heading angle of the vehicle has been considered for better accuracy. The challenge in designing this control system is to include the actuator dynamics as the response time to steer the front wheel is in the same order as that of the heading angle dynamics of the vehicle. Experiments have been conducted, analysis of data collected is presented and the resulting mathematical representation is explained in detail. Results from both simulation and experimental implementation are also compared. It has been found that the vehicle controller can be tuned effectively to achieve the desired heading angle changes up to twenty degrees within three seconds when the vehicle is moving at a speed of 1.4 m/sec.

Anti-Diabetic Activity of Eugenia jambolana Seed Kernels on Streptozotocin-Induced Diabetic Rats

S. Subramanian,K. Sivagnanam,K. Ravi 한국식품영양과학회 2004 Journal of medicinal food Vol.7 No.2

The present study evaluated the hypoglycemic activity of different parts of Eugenia jambolana seeds such as whole seed, kernel, and seed coat on streptozotocin-induced diabetic rats. Administration of the ethanolic extract of kernel at a concentration of 100 mg/kg of body weight significantly decreased the levels of blood glucose, blood urea, and cholesterol, increased glucose tolerance and levels of total proteins and liver glycogen, and decreased the activities of glutamate oxaloacetate transaminase and glutamate pyruvate transaminase in experimental diabetic rats. Whole seed showed a moderate hypoglycemic effect, and seed coat did not show any hypoglycemic effect. The hypoglycemic efficacy was compared with that of glibenclamide, a standard hypoglycemic drug.

Anti-Inflammatory Activity of Cleome gynandra L. on Hematological and Cellular Constituents in Adjuvant-Induced Arthritic Rats

S. Subramanian,R.T. Narendhirakannan,M. Kandaswamy 한국식품영양과학회 2005 Journal of medicinal food Vol.8 No.1

Cleome gynandraL. (cat whiskers) has traditionally been used for the treatment of rheumatic and other in-flammatory conditions. In this work, the methanolic extract of the leaves of C. gynandraexhibited significant anti-inflam-matory activity in adjuvant-induced arthritic rats. Phytochemical screening was carried out to ascertain the qualitative com-position of the leaves. Arthritis was induced by Freund’s complete adjuvant. A significant decrease in paw edema with aremarkable increase in body weight was observed following oral administration of the leaf extract (150 mg/kg of body weight).The alterations in hematological and other biochemical parameters were restored to near normal after a treatment period of30 days. These results demonstrate that the plant extract has no harmful effect and exerts in vivo anti-inflammatory proper-ties against adjuvant-induced arthritis.

Hypoglycemic Effect of Aloe vera Gel on Streptozotocin-Induced Diabetes in Experimental Rats

S. Subramanian,K. Sivagnanam,K. Ravi,S. Rajasekaran 한국식품영양과학회 2004 Journal of medicinal food Vol.7 No.1

In the present study an attempt has been made to evaluate the presence of hypoglycemic activity in the alco-holic extract of Aloe vera gel. Effects of oral administration of A. veraextract at a concentration of 200 and 300 mg/kg ofbody weight on (a) normal fasted rats, (b) oral glucose-loaded rats, and (c) streptozotocin-induced diabetic rats have beenstudied. A. veraextract maintain the glucose homeostasis by controlling the carbohydrate metabolizing enzymes.

Inclusion of polyaniline in electrodeposited bismuth sulphide thin films: Synthesis and characterization

S. Subramanian,P. Chithra lekha,D. Pathinettam Padiyan 한국물리학회 2009 Current Applied Physics Vol.9 No.5

Structural, electrical and optical properties of polyaniline (PAni) doped Bi2S3 composite thin films prepared by electrodeposition method are reported. X-ray diffraction pattern indicates its polycrystalline nature and crystallite size increases with increase in the concentration of PAni. FTIR studies reveal that the dopant PAni has affected the absorption phenomenon in the IR region of the Bi2S3 thin films. The optical band gap energy is found to be 1.91 eV for as-deposited Bi2S3 thin film and it decreases with increase in the concentration of PAni. The morphology of the doped films changes due to the addition of PAni. in the concentration of PAni. The morphology of the doped films changes due to the addition of PAni. The conduction results from a hopping due to localized states in the temperature range 300–358 K. Above 358 K, the conduction process is explained by the traps at grain boundaries of partially depleted grains.

Investigations on the structural, optical and electronic properties of Nd doped ZnO thin films

Subramanian, M,Thakur, P,Gautam, S,Chae, K H,Tanemura, M,Hihara, T,Vijayalakshmi, S,Soga, T,Kim, S S,Asokan, K,Jayavel, R Institute of Physics [etc.] 2009 Journal of Physics. D, Applied Physics Vol.42 No.10

<P>We report the synthesis and characterization of Nd doped ZnO thin films grown on Si (1 0 0) substrates by the spray pyrolysis method. The surface morphology of these thin films was investigated by scanning electron microscopy and shows the presence of randomly distributed structures of nanorods. Grazing angle x-ray diffraction studies confirm that the doped Nd ions occupied Zn sites and these samples exhibited a wurtzite hexagonal-like crystal structure similar to that of the parent compound, ZnO. The micro-photoluminescence measurement shows a decrease in the near band edge position with Nd doping in the ZnO matrix due to the impurity levels. The near-edge x-ray absorption fine structure (NEXAFS) measurements at the O K edge clearly exhibit a pre-edge spectral feature which evolves with Nd doping, suggesting incorporation of more charge carriers in the ZnO system and the presence of strong hybridization between O 2p–Nd 5d orbitals. The Nd M<SUB>5</SUB> edge NEXAFS spectra reveal that the Nd ions are in the trivalent state.</P>