Simultaneous co-immobilization of enzyme and a redox mediatorin polypyrrole film for the fabrication of an amperometricphenol biosensor

Rajesh,S.S. Pandey,W. Takashima,K. Kaneto 한국물리학회 2005 Current Applied Physics Vol.5 No.2

A conducting polypyrrole lm has been prepared on indium tin oxide coated glass plate by electropolymerization of pyrrole in anaqueous solution of enzyme, tyrosinase (PPO), and a redox mediator potassium hexacyanoferrate (II). The enzyme retains its bio-activity well within the polymer lm. Phenol concentration in aqueous solution was quantitatively estimated by monitoring the elec-tron exchange occurring in redox mediator within the polymer matrix i.e. direct reduction of Fe (III) to Fe (II) ion at +0.12V vs. Ag/AgCl. The results of amperometric response measurements conducted on enzyme electrode (PPO/Fe2+/PPY/ITO) show a sensitivityof 0.33 AM. 1 cm. 2 and a linear response range of 4.5107.4l M for phenol in aqueous medium. The electrode exhibits a responsetime of about 80 second and is stable for 4 months at 4.C..

Enhancement of the crystalline perfection of <0 0 1> directed KDP single crystal

P. Rajesh,S. Sreedhar,K. Boopathi,S. Venugopal Rao,P. Ramasamy 한국물리학회 2011 Current Applied Physics Vol.11 No.6

<0 0 1> directed good quality potassium dihydrogen phosphate (KDP) single crystal has been grown by Sankaranarayanan―Ramasamy (SR) method with the vision to improve the crystalline perfection and efficiency. A seed crystal of diameter 25 × 15 × 3 mm^3 was mounted in the ampoule, where the diameter of the ampoule was much bigger than the seed. The size of the crystal grown was 30 × 20 × 60 mm^3. The obtained transparency for the crystal grown by SR method is 93% and by conventional method is 85% in the entire visible region. The HRXRD analysis indicates that the crystalline perfections of the crystals are excellent without having any very internal structural grain boundaries. The obtained FWHM for conventional method grown crystal is 12 arc s and for SR method is 6 arc s. Low dielectric loss indicates that the <0 01> directed crystal contains minimum defects. Higher mechanical stability was observed in SR method grown KDP compared to the other. Laser damage threshold value has been determined using Nd:YAG laser operating at 1064 nm. The optical transmission study and the powder SHG measurement show the suitability of the ingot for nonlinear optical applications.

Disperser-induced bacterial disintegration of partially digested anaerobic sludge for efficient biomethane recovery

Banu, J. Rajesh,Kannah, R. Yukesh,Kavitha, S.,Gunasekaran, M.,Yeom, Ick Tae,Kumar, Gopalakrishnan Elsevier 2018 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.347 No.-

<P><B>Abstract</B></P> <P>The present study highlights the options to enhance the methane potential of partially digested anaerobic sludge using disperser-induced bacterial disintegration. Floc dispersion with no biomass disintegration was achieved at a disperser-specific energy input of 9.5 kJ/kg TS. The outcomes of both sole bacterial disintegration (S-BD) and disperser-induced bacterial disintegration (D-BD) were assessed in terms of changes in lysate, biopolymer release and increase in biodegradability and methane generation. A higher lysate solubilization of about 22.4% was achieved in D-BD compared to S-BD (11.3%), indicating the efficiency of floc dispersion prior to bacterial disintegration. The biochemical methane result implies that D-BD shows higher methane potential of 0. 279 gCOD/gCOD. Considering the overall outcome achieved in this study, disperser-induced bacterial disintegration is proved to be an effective disintegration process for enhanced biodegradation and higher methane production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Disintegration of digested sludge is a promising technique for bioenergy generation. </LI> <LI> Floc dispersion was achieved at lesser disperser input energy of 9.5 kJ/kg TS. </LI> <LI> A higher lysate solubilization of 22.4% was achieved in floc dispersed sample. </LI> <LI> Biopolymer release of floc dispersed sludge was higher (1379.8 and 394.2 mg/L) </LI> <LI> Result of methane reveals the effect of floc dispersion prior to disintegration. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Comprehensive studies of hydrogeochemical processes and quality status of groundwater with tools of cluster, grouping analysis, and fuzzy set method using GIS platform: a case study of Dalcheon in Ulsan City, Korea.

Venkatramanan, S,Chung, S Y,Rajesh, R,Lee, S Y,Ramkumar, T,Prasanna, M V Ecomed 2015 Environmental Science and Pollution Research Vol.22 No.15

<P>This research aimed at developing comprehensive assessments of physicochemical quality of groundwater for drinking and irrigation purposes at Dalcheon in Ulsan City, Korea. The mean concentration of major ions represented as follows: Ca (94.3 mg/L)?>?Mg (41.7 mg/L)?>?Na (19.2 mg/L)?>?K (3.2 mg/L) for cations and SO4 (351 mg/L)?>?HCO3 (169 mg/L)?>?Cl (19 mg/L) for anions. Thematic maps for physicochemical parameters of groundwater were prepared, classified, weighted, and integrated in GIS method with fuzzy logic. The maps exhibited that suitable zone of drinking and irrigation purpose occupied in SE, NE, and NW sectors. The undesirable zone of drinking purpose was observed in SW and central parts and that of irrigation was in the western part of the study area. This was influenced by improperly treated effluents from an abandoned iron ore mine, irrigation, and domestic fields. By grouping analysis, groundwater types were classified into Ca(HCO3)2, (Ca,Mg)Cl2, and CaCl2, and CaHCO3 was the most predominant type. Grouping analysis also showed three types of irrigation water such as C1S1, C1S2, and C1S3. C1S3 type of high salinity to low sodium hazard was the most dominant in the study area. Equilibrium processes elucidated the groundwater samples were in the saturated to undersaturated condition with respect to aragonite, calcite, dolomite, and gypsum due to precipitation and deposition processes. Cluster analysis suggested that high contents of SO4 and HCO3 with low Cl was related with water-rock interactions and along with mining impact. This study showed that the effluents discharged from mining waste was the main sources of groundwater quality deterioration.</P>

Recommended girth weld spacing on process pipe

Rajesh S.R.(라제쉬),Chang-Min Hyun(현충민) 대한용접·접합학회 2019 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2019 No.5

Solution-based synthesis of high yield CZTS (Cu₂ZnSnS₄) spherical quantum dots

Rajesh, G.,Muthukumarasamy, N.,Subramanian, E.P.,Venkatraman, M.R.,Agilan, S.,Ragavendran, V.,Thambidurai, M.,Velumani, S.,Yi, J.,Velauthapillai, D. Academic Press 2015 Superlattices and microstructures Vol.77 No.-

High yield CZTS quantum dots have been synthesized using simple precursors by chemical precipitation technique. Formation mechanism of CZTS spherical quantum dots also has been investigated. According to the mechanism, copper sulfide nuclei firstly forms, and serves as the starting point for the nucleation and growth of CZTS. X-ray diffraction pattern, X-ray photoelectron spectra (XPS) and Raman spectra reveals the formation of pure kesterite structure Cu<SUB>2</SUB>ZnSnS<SUB>4</SUB> nanoparticles. HRTEM analysis reveals the formation of CZTS quantum dots with an average particle size of ~8.3nm. The elemental distribution of CZTS quantum dots studied using STEM elemental mapping reveals that Cu, Zn, Sn and S are present in the sample. The photoluminescence spectra of CZTS exhibit a broad red emission band at 657nm. The optical band gap is shifted to the higher energy side and it shows the presence of quantum confinement effect.

Performance of leaf springs made of composite material subjected to low frequency impact loading

S. Rajesh,G. B. Bhaskar,J. Venkatachalam,K. Pazhanivel,Suresh Sagadevan 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.9

This paper illustrates the possibility of replacing existing conventional steel-leaf spring by the leaf spring made by tailoring the layup of composite laminates. The dimensions of the existing conventional middle leaf (spring) of a commercial vehicle were chosen for the design and manufacture of die for moulding the composite leaves. Accordingly, suspension springs of composites of different layups with glass and carbon were fabricated and tested for flexure response. It is to be noted here that the cross sectional area of the composite leaf spring was the same as of the conventional leaf spring. By using universal testing machine, load per deflection and maximum load for each of the composite leaf springs were evaluated. Apart from these, the specimens were exposed to low frequency impact loading with specific duration of cycles and subsequently the flexure response was also evaluated. The low frequency impact on the composite leafs was effected with a laboratory loading set-up in a milling machine. Experimental results indicated the superior flexure response of the hybrid composites (with glass fiber at starting phase and carbon fiber at the end) and suggested possible alternative on comparison with the conventional spring.

Solitary fibrous tumor of the liver - An unusual entity

Rajesh S Shinde,Amit Gupta,Mahesh Goel,Shraddha Patkar 한국간담췌외과학회 2018 Annals of hepato-biliary-pancreatic surgery Vol.22 No.2

The Effect of Welding Residual Stress on Whole Structure with T-Joint RHS

Rajesh S. R.,Bang H. S.,Kim H. The Korean Welding and Joining Society 2005 International journal of Korean welding society Vol.5 No.1

In the field of welding the mechanical behavior of a welded structure under consideration may be predicted via heat transfer and welding residual stress analysis. Usually such numerical analyses are limited to small regular mesh models or test specimens. Nevertheless, there is very few strength assessment of the whole structure that includes the effect of welded residual stress. The present work is based on the specialized finite element codes for the calculation of nonlinear heat transfer details and residual stress including the external load on the welded RHS (Rectangular Hollow Section) T-joint connections of the whole structure. First the thermal history of the combined fillet and butt-welded T-joint equal width cold-formed RHS are calculated using nonlinear finite element analysis (FEA) considering the quarter model of the joint. Then using this thermal history the residual stress around the joints has been evaluated. To validity the FEA result, the calculated residual stresses were compared with the available experimental results. The residual stress obtained from the quarter model is mapped to the full model and then to the whole structure model using FEM codes. The results from the FEM codes were exported to the commercial package for visualization and further analysis applying loads and boundary conditions on the whole structure. The residual stress redistribution along with the external applied load is examined computationally.

Effect of Cation Binding Agents on Sludge Solubilization Potential of Bacteria

S. Gopi Kumar,J. Merrylin,S. Kaliappan,S. Adish Kumar,염익태,J. Rajesh Banu 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.2

The aim of the present study is to increase sludge solubilization potential of bacteria by the addition of cation binding agents. During the study, three strains of bacteria B1, B2 and B3 were isolated from waste activated sludge acclimatized to a thermophilic condition (55°C). Using these strains the mixed liquor suspended solids degradation was 67, 59, and 33% and the chemical oxygen demand solubilization enhancement was 71, 62, and 36%compared with the control. Cation binding agents such as citric acid, ethylenediaminetetraacetate and sodium tripolyphosphate were added to enhance the sludge solubilization further. Among these, citric acid along with B1 was more effective in solubilization with the mixed liquor suspended solids degradation of 110% and the chemical oxygen demand solubilization enhancement of 115%. 16s rRNA technique was used to identify the bacterial species B1 and it was found to be Bacillus licheniformis. It was also observed that mixed liquor suspended solids reduced rapidly when more soluble chemical oxygen demand was released, thereby increasing sludge solubilization.