Crystal Structure Analysis of N,N′-bis(3-chloro-2-methylsalicylidene)-1,4- butanediamine

P. Sharmila, R. Rajesh, R. Venkatesan2, Jagadeesan Ganapathy, and S. Aravindhan 조선대학교 기초과학연구원 2016 조선자연과학논문집 Vol.9 No.4

The crystal structure of the saliciline derivatives N,N′-bis(3-chloro-2-methylsalicylidene)-1,4-butanediamine (C20H22Cl2N2O2) has been determined from single crystal X-ray diffraction data. In the title compound crystallizes in the triclinic space group Pī with unit cell dimension a= 4.6085(3) Å, b=5.9747(3) Å and c= 5.9747(3) Å [α=83.889 (4)°, β= 86.744(5)° and γ= 82.085(5)°]. The title compound is essentially planar conformation. The compound lies across a crystallographic inversion centre and adopts E configurations with respect to the C-N bonds. The crystal packing of the molecules of compound is stabilized through weak O-H...N intra molecular interactions Keywords: Chromene; Schiff Base Ligand; Single Crystal Structure; X-ray Diffraction

Optimization of CNT and TFT Parameters for Maximum Transconductance and Safe Temperature Operation of Carbon Nanotube Thin-Film Transistors (CNT-TFTs) Employed in Flat Panel Displays

R. Venkatesan,R. Joseph Daniel,P. Shanmugaraja 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.1

Thin Film Transistors (TFTs) have lived to see its significant technological improvement for various display applications in recent years. Carbon nanotube (CNT) based TFT technologies have been found to be a promising component for next generation flexible electronics and flat panel displays in view of CNTs high carrier mobility, device stability and mechanical flexibility. However, the design of CNT-TFT is still not well established, especially with a view to achieve the best performance still protecting thermal stability. In this study, the authors had analysed the device structure and operation of transistor in which carbon nanotubes act as active channel region. CNT-TFT with different device geometrics and CNT physical parameters such as channel length, channel width, CNT tube length, network density and its orientation have been extensively studied using NanoNet simulation tool. This study has thrown new insight into the device performance characteristics of CNT-TFTs. The results show that it is essential to fix the length of the channel more than 5 μm for restricting the device temperature at 300 K and it can be brought down as low as 3 μm if the maximum operating temperature can be 400 K. Comparison with already reported experimental results show that the TFT parameters returned by the simulation experiments and presented in this paper match closely.

Lactucopicrin ameliorates oxidative stress mediated by scopolamine-induced neurotoxicity through activation of the NRF2 pathway

Venkatesan, R.,Subedi, L.,Yeo, E.J.,Kim, S.Y. Pergamon Press 2016 Neurochemistry International Vol.99 No.-

Cholinergic activity plays a vital role in cognitive function, and is reduced in individuals with neurodegenerative diseases. Scopolamine, a muscarinic cholinergic antagonist, has been employed in many studies to understand, identify, and characterize therapeutic targets for Alzheimer's disease (AD). Scopolamine-induced dementia is associated with impairments in memory and cognitive function, as seen in patients with AD. The current study aimed to investigate the molecular mechanisms underlying scopolamine-induced cholinergic neuronal dysfunction and the neuroprotective effect of lactucopicrin, an inhibitor of acetylcholine esterase (AChE). We investigated apoptotic cell death, caspase activation, generation of reactive oxygen species (ROS), mitochondrial dysfunction, and the expression levels of anti- and pro-apoptotic proteins in scopolamine-treated C6 cells. We also analyzed the expression levels of antioxidant enzymes and nuclear factor (erythroid-derived 2)-like 2 (NRF2) in C6 cells and neurite outgrowth in N2a neuroblastoma cells. Our results revealed that 1 h scopolamine pre-treatment induced cytotoxicity by increasing apoptotic cell death via oxidative stress-mediated caspase 3 activation and mitochondrial dysfunction. Scopolamine also downregulated the expression the antioxidant enzymes superoxide dismutase, glutathione peroxidase, and catalase, and the transcription factor NRF2. Lactucopicrin treatment protected C6 cells from scopolamine-induced toxicity by reversing the effects of scopolamine on those markers of toxicity. In addition, scopolamine attenuated the secretion of neurotrophic nerve growth factor (NGF) in C6 cells and neurite outgrowth in N2a cells. As expected, lactucopicrin treatment enhanced NGF secretion and neurite outgrowth. Our study is the first to show that lactucopicrin, a potential neuroprotective agent, ameliorates scopolamine-induced cholinergic dysfunction via NRF2 activation and subsequent expression of antioxidant enzymes.

Strength and Durability Properties of Geopolymer Concrete made with Ground Granulated Blast furnace Slag and Black Rice Husk Ash

R. Prasanna Venkatesan,K. C. Pazhani 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.6

This paper presents an experimental study on the strength and durability properties of Geopolymer concrete prepared using Ground Granulated Blast Furnace Slag (GGBS) and Black Rice Husk Ash (BRHA). The Geopolymer concrete was prepared with GGBS as the primary binder instead of cement and BRHA was replaced with GGBS at various proportions such as 10%, 20% and 30%. The effect of curing temperature on the compressive strength of Geopolymer concrete was studied in addition to the flexural and split tensile strengths. Studies on the durability performance under Sorptivity, Rapid Chloride Permeability Test and Accelerated corrosion were also made. The test results show that the strength of Geopolymer concrete increases with increase in curing temperature. Addition of BRHA in Geopolymer concrete beyond 10% retards the strength development yet the strengths are well above the target for up to 20% replacement levels. At the same time, addition of BRHA significantly improves the durability with reduced sorptivity and chloride permeability when compared to the control concrete. Higher corrosion initiation and delayed cracking time were observed up to 20% BRHA replacement in Geopolymer concrete.

Analytical, numerical and experimental approach for design and development of optimal die profile for the cold extrusion of B4C DRMM Al 6061 composite billet into hexagonal section

R. Venkatesan,C. Venaktesh 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.12

Aluminium based matrix composites with boron carbide as particle reinforcement called Discontinuous reinforced metal matrixcomposites (DRMMs) possess high specific strength, high elastic modulus, good wear resistance, damping capacity and thermalstability. But during the development of DRMM composites, compression process like extrusion is an advisable secondary processfor homogenous structure. This research work investigates the metal flow behavior of Al-B4C based DRMM composite through sixdifferent die profiles namely third order polynomial, fourth order polynomial, cosine, elliptical, hyperbolic and conical geometry. Extrusion load, stress and strain distribution, and metal flow for above said die profiles are predicted by using analytical approachupper bound technique and compared with finite element method. Cosine and third order polynomial profiles are found to be mostoptimal in terms of homogenous and minimal extrusion load requirement. To validate the results, specially made Al-B4C compositethrough stir casting route was extruded from round to hexagon through an exclusively fabricated cosine die. Results observed from theexperiment have good agreement with both analytical and numerical.

EXPERIMENTAL VALIDATION OF A MATHEMATICAL MODEL OF A REED-VALVE RECIPROCATING AIR COMPRESSOR FROM AN AUTOMOTIVE-BRAKING SYSTEM

J. VENKATESAN,G. NAGARAJAN,R. V. SEENIRAJ,R. MURUGAN 한국자동차공학회 2010 International journal of automotive technology Vol.11 No.3

Mathematical simulation is the process of designing a model of a real system and then conducting experiments with the simulation to understand the system’s behavior. Mathematical simulation is widely used for investigating and designing compressors, and with a minimal number of simplifying assumptions, mathematical models can be used in conjunction with modern computing tools to solve complicated problems. A considerable amount of previous research has focused on the mathematical modeling of reciprocating air compressors used in automotive braking. The aim of the present work was to experimentally validate the mathematical model for such compressors. We present a simplified and effective mathematical model for estimating compressor performance, and this model can easily be executed using personal computers. Parameters such as compressor speed, discharge pressure and clearance volume were evaluated in terms of their effect on the thermodynamic behavior of compressors. The model can predict cylinder pressure, cylinder volume, cylinder temperature, valve lift and resultant torque at different crank angles; it can also predict the free air delivered and the indicated power of the compressor. Therefore, the model has been validated using experimental results.

In vitro and in vivo evaluation of gastro-retentive carvedilol loaded chitosan beads using Gastroplus(TM)

Praveen, R.,Prasad Verma, P.R.,Venkatesan, J.,Yoon, D.H.,Kim, S.K.,Singh, S.K. ELSEVIER 2017 INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES Vol.102 No.-

The objective of present investigation was to develop gastro-retentive controlled release system of carvedilol using biological macromolecule, chitosan. 3<SUP>2</SUP> full factorial design was adopted for optimization of tripolyphosphate (X<SUB>1</SUB>) and curing time (X<SUB>2</SUB>). Bead stability in 0.1N HCl, buoyancy duration, density, drug loading, dissolution efficiency and cumulative percentage release at 8th hour were evaluated as dependent variables. The levels of X<SUB>1</SUB> and X<SUB>2</SUB> of optimized formulation having maximum desirability was found to 2.0% w/v and 62.66min, respectively. The in silico predicted responses and observed response were found to be in good agreement (percent bias error: -13.295 to +13.269). SEM images showed numerous pores in the cross sectional image that renders buoyancy. AUC<SUB>0-~</SUB> of optimized formulation was 1.47 times higher as compared to suspension corroborating enhanced extent of absorption. T<SUB>max</SUB> and mean residence time were significantly higher from optimized formulation vis a vis suspension. In silico study indicated maximum regional absorption from the duodenum (94.1%) followed by jejunum (5.6%). Wagner-Nelson and Loo-Reigelman method were the preferred deconvolution approach over numerical deconvolution to establish IVIVC. In conclusion, the study showed that gastro-retentive controlled release system prepared using chitosan could be a potential drug carrier of carvedilol with improved bioavailability.

Crystal Structure Analysis of 4-Chloro-2{[(2-hydroxy-5-methylphenyl)amino]methyl}5-methylphenol

P. Sharmila, R. Rajesh, R. Venkatesan, Jagadeesan Ganapathy, and S. Aravindhan 조선대학교 기초과학연구원 2016 조선자연과학논문집 Vol.9 No.4

The crystal structure of the saliciline derivatives 4-chloro-2{[(2-hydroxy-5-methylphenyl)amino]methyl}5-methylphenol (C15H15ClNO2) has been determined from single crystal X-ray diffraction data. In the title compound crystallizes in the monoclinic space group P21/c with unit cell dimension a= 11.5241(2) Å, b=8.733(2) Å and c= 13.649(2) Å [α=90°, β= 130.876(2)° and γ= 90°]. the title compound are essentially planar conformation. The compound lies across a crystallographic inversion centre and adopts E configurations with respect to the C-N bonds. The crystal packing of the molecules of compound is stabilized through weak O-H...O inter molecular interactions Keywords: Chromene, Schiff Base Ligand, Single Crystal Structure, X-ray Diffraction

Research and Experimental Implementation of a CV-FOINC Algorithm Using MPPT for PV Power System

Arulmurugan, R,Venkatesan, T 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.4

This research suggests maximum power point tracking (MPPT) for the solar photovoltaic (PV) power scheme using a new constant voltage (CV) fractional order incremental conductance (FOINC) algorithm. The PV panel has low transformation efficiency and power output of PV panel depends on the change in weather conditions. Possible extracting power can be raised to a battery load utilizing a MPPT algorithm. Among all the MPPT strategies, the incremental conductance (INC) algorithm is mostly employed due to easy implementation, less fluctuations and faster tracking, which is not only has the merits of INC, fractional order can deliver a dynamic mathematical modelling to define non-linear physiognomies. CV-FOINC variation as dynamic variable is exploited to regulate the PV power toward the peak operating point. For a lesser scale photovoltaic conversion scheme, the suggested technique is validated by simulation with dissimilar operating conditions. Contributions are made in numerous aspects of the entire system, including new control algorithm design, system simulation, converter design, programming into simulation environment and experimental setup. The results confirm that the small tracking period and practicality in tracking of photovoltaic array.

Cryopreservation and Microencapsulation of a Probiotic in Alginatechitosan Capsules Improves Survival in Simulated Gastrointestinal Conditions

Paulraj Kanmani,R. Satish Kumar,N. Yuvaraj,K. A. Paari,V. Pattukumar,Venkatesan Arul 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.6

The aim of the present study was to focus on the impact of two different methods and the effects of cryoprotectants on the survival of a probiotic bacterium,Streptococcus phocae PI80, during storage. For the protection of freeze dried cells, the optimal storage conditions were determined with a high survival rate. After the freeze drying process, all cryoprotectants exhibited a protective effect on cell viability at all storage temperatures. High relative cell viability was observed when cells were incubated at −20°C, which was optimum for the protection of S. phocae PI80. Trehalose was the most promising cryoprotectant at all temperatures during the storage period of bacterial cells. The combination of trehalose + skim milk showed more than 85% survivability compared to other combinations at −20°C for 60 days. In addition,encapsulation of probiotic cells into alginate-chitosan gel capsules showed better survival of S. phocae cells (5.468 ±0.15 LogCFU/mL) with high bacteriocin activity at −20°C for six months. The cell-loaded microcapsules remained stable when treated with simulated gastric and intestinal fluids. After 6 h in vivo treatment, the capsules were found to be broken, releasing the probiotic cells directly into the intestinal system of rats. Therefore, microencapsulation was found to be the most efficient technique, which not only protected the cells for a longer time but also released the cells into the in vivo intestinal system.