Numerical study on a vertical plate with variable viscosity and thermal conductivity

Palani, G.,Kim, Kwang-Yong Springer-Verlag 2010 Archive of applied mechanics Vol.80 No.7

Free convection on an inclined plate with variable viscosity and thermal diffusivity

Palani, G.,Kirubavathi, J. D.,Kim, Kwang Yong Pleiades Publishing 2014 Thermophysics and Aeromechanics Vol.21 No.1

Numerically integrated modified virtual crack closure integral technique for 2-D crack problems

Palani, G.S.,Dattaguru, B.,Iyer, Nagesh R. Techno-Press 2004 Structural Engineering and Mechanics, An Int'l Jou Vol.18 No.6

Modified virtual crack closure integral (MVCCI) technique has become very popular for computation of strain energy release rate (SERR) and stress intensity factor (SIF) for 2-D crack problems. The objective of this paper is to propose a numerical integration procedure for MVCCI so as to generalize the technique and make its application much wider. This new procedure called as numerically integrated MVCCI (NI-MVCCI) will remove the dependence of MVCCI equations on the type of finite element employed in the basic stress analysis. Numerical studies on fracture analysis of 2-D crack (mode I and II) problems have been conducted by employing 4-noded, 8-noded (regular & quarter-point), 9-noded and 12-noded finite elements. For non-singular (regular) elements at crack tip, NI-MVCCI technique generates the same results as MVCCI, but the advantage for higher order regular and singular elements is that complex equations for MVCCI need not be derived. Gauss numerical integration rule to be employed for 8-noded singular (quarter-point) element for accurate computation of SERR and SIF has been recommended based on the numerical studies.

Hepatoprotective and antioxidant effects of Monochoria vaginalis against acetaminophen-induced hepatotoxicity in rats

Palani, S.,Raja, S.,Sakthivel, K.,Devi, K.,Kumar, B. Senthil Kyung Hee Oriental Medicine Research Center 2010 Oriental pharmacy and experimental medicine Vol.10 No.1

The present study was aimed to investigate the hepatoprotective and antioxidant activities of ethanol extract from Monochoria vaginalis (250 mg/kg and 500 mg/kg B/W) on acetaminophen (APAP) induced rat hepatic injury. Monochoria vaginalis is a traditional medicinal plant that is commonly used to treat and improve liver conditions in India and other Asian countries. The development of hepatotoxicity induced by APAP is promoted by oxidative stress. APAP treated group significantly (P < 0.01) elevated the serum enzymatic levels like glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, alkaline phosphatase (SALP), total bilirubin and malondialdehyde (MDA), which were restored towards normalization significantly (P < 0.01) thanol extract of yonochoria vagin is (EEMV). In addition, the EEMV significantly (P < 0.01) elevated the decreased level of total protein and antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase, glutathione-s-transferase and reduced glutathione. Apart from these, histopathological changes also showed the protective nature of the EEMV against APAP induced hepatic damage in liver tissues. The activity of EEMV at 500 mg/kg B/W was comparable to the standard drug silymarin (25 mg/kg B/W). In conclusion, these data suggest that the EEMV possess hepatoprotective and antioxidant effects against APAP-induced hepatotoxicity and oxidative stress in rats.

In-Situ UV Illuminated Highly Conductive, Transparent ZnO Thin Film Electrode

Palani Indirajith,Myung Mo Sung 한국진공학회 2020 한국진공학회 학술발표회초록집 Vol.2020 No.2

Theoretical and Computational Analysis of LNG Evaporator

Palani Kumar Chidambaram,Seok Woo Son,Heuy Dong Kim(김희동),Dong Wook Kim(김동욱),Yang Myung Jo(조양명) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12

Theoretical and numerical predictions on fluid flow and heat transfer in a typical LNG evaporator is performed. Methane is used in lieu of LNG as it constitutes over 80% of LNG. The theoretical predictions are performed by simple energy balance between the steam and methane. This is augmented by the mass transfer between the liquid phase methane and gas phase methane. The theoretical predictions are made to calculate the pressure drop and temperature drop in the steam tubes. Numerical simulations are carried out by solving the governing equations of multiphase flow in a portion of the evaporator domain with a single layer of steam pipe. The basic flow equations of continuity, momentum and energy equations form the governing equations along with equations of species transport. Multiphase modelling is incorporated using VOF method. Liquid methane is taken as primary phase. It vaporizes into gaseous methane which is taken to be secondary phase. Steam is taken as another secondary phase which flows through the heating coils. Closure for turbulence is modelled by a two equation turbulence model. Both the analytical and numerical predictions match well with each other. Further parametric studies are planned based on the current research.

Spray characteristics of diesel and derivatives in direct injection diesel engines with varying injection pressures

Raghu Palani,Nallusamy Nallusamy,Pitchandi K 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10

The combustion and emission characteristics of inedible oils and their derivatives are quite different from those of mineral diesel; inparticular, inedible oils and their derivatives present higher molecular, relative density, and vaporization characteristics. These propertiesexert great impacts on the fuel spray as well as the interactions of this spray with air in the combustion chamber. Thus, examining spraycharacteristics, including spray cone angle, spray tip penetration, spray area, and fuel atomization, is necessary. The spray characteristicsof fuel mainly depend on the fuel injection pressure, density, viscosity, ambient pressure, and temperature. Among these parameters, fuelinjection pressure significantly affects the spray structure. In this study, experiments were conducted using diesel, jatropha oil methylester, karanja oil methyl ester, and two biodiesel blended fuels (JB20 and KB20)] as fuels in a diesel engine with different injection pressures. Optical techniques for spray visualization and image processing are very efficient tools for analyzing the spray parameters of thetested fuels. Macroscopic spray properties, such as spray tip penetration, spray cone angle, and spray area, were acquired from imagescaptured by a high-speed video camera. The Sauter mean diameter and spray volume of all of the tested fuels were also estimated. Experimentalresults showed that the biodiesel blends demonstrate features different from those of diesel fuel. KB100 presented the highestspray tip penetration and spray area, followed by JB100 JB20, KB20 and diesel. Diesel fuel showed the best spray parameters, followedby JB20, KB20, KB100 and JB100. The tested fuels exhibited better spray characteristics at higher injection pressures than at lower ones.

Alternating and Merged Droplets in a Double T-junction Microchannel

Harish Palani Naga Surya,Sajeesh Parayil,Utsab Banerjee,Subhash Chander,Ashis Kumar Sen 한국바이오칩학회 2015 BioChip Journal Vol.9 No.1

In this work, we report experimental andnumerical studies of alternating and merged dropletsin a double T-junction microchannel. The microchanneldevice is fabricated using PDMS substrate and experimentsare performed with mineral oil with surfactantas the continuous phase and aqueous glycerol asthe discrete phase. Based on the flow rate fraction φand Capillary number Ca, four different flow regimesare identified: merging, stable alternating droplets, alternatingdroplets with transition and laminar. A numericalmodel that employs volume-of-fluid formulationsis used to predict the alternating droplet generationprocess. In the stable alternating droplet regime,the effect of the discrete phase flow rate ratio α on thedroplet diameter ratio β is experimentally studied andcompared with that predicted from the simulations. Itis observed that the droplet diameter ratio β increaseslinearly with increase in the flow rate ratio α and agood match between experiments and simulations isobserved. The diameters of droplets at different Capillarynumbers Ca generated using single and doubleT-junction microchannels are compared and it is observedthat, at low Ca, the double T-junction generateslarger droplets as compared to single T-junction. In merged droplet regime, the effect of the continuousphase flow rate Qc and discrete phase viscosity μd ondiameter dm and interdistance between the droplets λof the merged droplets are studied. It is observed thatthe merged droplet diameter dm is reduced and interdistancebetween the droplets λ increases with increasein the continuous phase flow rate Qc. As the viscosityof the discrete phase μd increases, the diameter dm andinterdistance between the droplets λ of the mergeddroplets decreases.

Numerical solutions for unsteady flow past a semi-infinite inclined plate with temperature oscillations

G.Palani,김광용 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.6

A study of the velocity and thermal boundary layers on a semi-infinite inclined plate with temperature oscillations ispresented in this work. The non-linear, coupled parabolic integro-partial differential equations governing flow and heat transfer have been solved numerically using an implicit finite difference scheme of Crank-Nicolson type. The numerical values for the flow field, temperature, shearing stress, and heat transfer coefficients are presented in a graphical form. It is observed that the velocity and temperature profiles decrease as the frequency parameter increases.

Hepatoprotective and antioxidant effects of Monochoria vaginalis against acetaminophen-induced hepatotoxicity in rats

S Palani,S Raja,K Sakthivel,K Devi,B Senthil Kumar 경희대학교 융합한의과학연구소 2010 Oriental Pharmacy and Experimental Medicine Vol.10 No.1

The present study was aimed to investigate the hepatoprotective and antioxidant activities of ethanol extract from Monochoria vaginalis (250 mg/kg and 500 mg/kg B/W) on acetaminophen (APAP)induced rat hepatic injury. Monochoria vaginalis is a traditional medicinal plant that is commonly used to treat and improve liver conditions in India and other Asian countries. The development of hepatotoxicity induced by APAP is promoted by oxidative stress. APAP treated group significantly (P < 0.01) elevated the serum enzymatic levels like glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, alkaline phosphatase (SALP), total bilirubin and malondialdehyde (MDA), which were restored towards normalization significantly (P < 0.01)thanol extract of yonochoria vagin is (EEMV). In addition, the EEMV significantly (P < 0.01)elevated the decreased level of total protein and antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase, glutathione-s-transferase and reduced glutathione. Apart from these, histopathological changes also showed the protective nature of the EEMV against APAP induced hepatic damage in liver tissues. The activity of EEMV at 500 mg/kg B/W was comparable to the standard drug silymarin (25 mg/kg B/W). In conclusion, these data suggest that the EEMV possess hepatoprotective and antioxidant effects against APAP-induced hepatotoxicity and oxidative stress in rats.