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Corrosion studies of high pressure die-cast Al-Si-Ni and Al-Si-Ni-Cu alloys
Arthanari, Srinivasan,Jang, Jae Cheol,Shin, Kwang Seon Elsevier 2018 Journal of alloys and compounds Vol.749 No.-
<P><B>Abstract</B></P> <P>Corrosion behavior of high pressure die-cast Al-Si-Ni alloys (Al-3Si-1Ni (SN31) and Al-3Si-3Ni (SN33)) with and without copper (Cu) addition has been investigated. Corrosion behavior was assessed in 3.5 wt% NaCl by electrochemical and immersion corrosion techniques. The presence of single phase pure Si and binary Al<SUB>3</SUB>Ni phases were confirmed from the X-ray diffraction (XRD) and microstructural studies for SN31 and SN33 alloys. Interestingly, Cu addition (1 at.%) resulted in formation of Al<SUB>3</SUB>Ni<SUB>2</SUB> phase along with a marginal decrease in Al<SUB>3</SUB>Ni fraction and did not produce any Cu containing phases. Potententiodynamic polarization studies revealed an increase in corrosion current density (i<SUB>corr</SUB>) value as the Ni content was increased. However, the addition of Cu to SN31 and SN33 alloys increased their corrosion resistance. Electrochemical impedance spectroscopy studies confirmed the higher charge transfer resistance (R<SUB>ct</SUB>) values for the Cu added alloys. Immersion corrosion test results revealed that, the corrosion rate of Cu added alloys were three times lower than SN31 and SN33 alloys. In the SN alloys, increase in corrosion rate is attributed to the increase of Al<SUB>3</SUB>Ni phase as the Ni content was increased. The added Cu dissolves in the Al alloys and also reduce the Al<SUB>3</SUB>Ni fraction thereby improved their corrosion resistance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Al-Si alloys with Ni and Cu were developed by high pressure die-casting. </LI> <LI> Influence of Ni and Cu addition on the corrosion behavior was investigated. </LI> <LI> Corrosion resistance was assessed by electrochemical and immersion tests. </LI> <LI> Increase in Ni content decreased the corrosion resistance of the Al-Si alloy. </LI> <LI> Addition of Cu improved the corrosion resistance of Al-Si-Ni alloys. </LI> </UL> </P>
Corrosion Behavior of High Pressure Die Cast Al-Ni and Al-Ni-Ca Alloys in 3.5% NaCl Solution
Arthanari, Srinivasan,Jang, Jae Cheol,Shin, Kwang Seon The Corrosion Science Society of Korea 2017 Corrosion Science and Technology Vol.16 No.2
In this investigation corrosion behavior of newly developed high-pressure die cast Al-Ni (N15) and Al-Ni-Ca (NX1503) alloys was studied in 3.5% NaCl solution. The electrochemical corrosion behavior was evaluated using open circuit potential (OCP) measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. Potentiodynamic polarization results validated that NX1503 alloy exhibited lower corrosion current density ($i_{corr}$) value ($5.969{\mu}A/cm^2$) compared to N15 ($7.387{\mu}A/cm^2$). EIS-Bode plots revealed a higher impedance (${\mid}Z{\mid}$) value and maximum phase angle value for NX1503 than N15 alloy. Equivalent circuit curve fitting analysis revealed that surface layer ($R_1$) and charge transfer resistance ($R_{ct}$) values of NX1503 alloy was higher compared to N15 alloy. Immersion corrosion studies were also conducted for alloys using fishing line specimen arrangement to simultaneously measure corrosion rates from weight loss ($P_W$) and hydrogen volume ($P_H$) after 72 hours and NX1503 alloy had lower corrosion rate compared to N15 alloy. The addition of Ca to N15 alloy significantly reduced the Al3Ni intermetallic phase and further grain refinement may be attributed for reduction in the corrosion rate.
Evaluation and Characterization of Fluroquinone Antibiotic loaded in to Polymeric Nanofibers.
Arthanari Saravanakumar(아따나리 사라바나 쿠멀),Mani Ganesh(마니가니쉬),Jun Ho Jang(장준호),Je O Choi(최제오),Yun Ho Cho(조윤호),Jung Ho Lee(이정호),Seung Eun Cha(차성은),Han Seok Oh(오한석),Deok Han Kwon(권덕한),장현태 한국산학기술학회 2014 한국산학기술학회 학술대회 Vol.2014 No.2
The aim of this study was to develop novel biomedicated electrospun nanofiber for controlled release. Pre-formulation studies were carried out for nanofibers of sodium alginate(2 wt.%) (SA)/polyvinyl alcohol(10 wt.%) (PVA) (2:8, 3:7 and 1:9) composites by an electrospinning technique. The morphology and average diameter of the nanofibers were investigated by scanning electron microscopy. The optimum ratio(3:7) was used for loading of gatifloxacin hydrochloride (GH) (1wt.%), found to form smooth fibers with uniform structures. The drug entrapment, in the composite nanofibers was confirmed by scanning electron microscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA),differential scanning calorimetry (DSC) and swelling behavior. The drug release behavior was investigated by using phosphate buffered saline (PBS) (pH 7.4) at 37°C for 24hrs. XRD and FT-IR data demonstrates that there are good interactions between PVA and SA caused by possibly hydrogen bonds. As much as 90 % of the GH was released from the electrospun fibers within 6hrs of incubation, beyond this the release was sustained for 24hrs. The thickness of nanofibers greatly influenced the initial release and rate of drug release. Moreover, GH loaded sodium alginate / PVA composite nanofibers exhibited a useful and convenient method for electrospinning in order to control the rate and period of drug release in wound healing applications.
Arthanari Saravanakumar,장현태,Mani Ganesh,Jayabalan Jayaprakash 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.28 No.-
A single step green synthesis of silver nanoparticles (AgNPs) from silver nitrate (AgNO3) using Cassia toraleaves extract as reducing agent by a simple and ecofriendly method in room temperature. Thebiosynthesized nanoparticles were characterized by UV-Vis, Scanning electron microscopy (SEM)coupled with X-ray energy dispersive spectrophotometer (EDAX), X-ray diffraction (XRD) and Fouriertransform infrared spectroscopy (FTIR). In UV-Vis spectroscopy results, the lmax observed at 425 nm. TheAgNPs synthesized were spherical, hexagonal and irregular in shapes. The EDAX and XRD spectrumconfirms that the presence of silver ions and crystalline nature of synthesized AgNPs. FTIR showed thefunctional groups such as C55O, N–H and C–N groups involved in the reduction of Ag+ to Ag. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay was performed and it showed percentageinhibition in concentration dependent manner. The synthesized AgNPs showed antibacterial activityagainst Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis in differentextents and the higher activity was observed in Escherichia coli.
Arthanari Saravanakumar(아따나리 사라바나 쿠멀),Mani Ganesh(마니 가니쉬),Mei Mei Peng(펭메이메이),Abidov Sh Aziz(아비도프아지즈),Hyun Tae Jang(장현태) 한국산학기술학회 2014 한국산학기술학회 학술대회 Vol.2014 No.2
Antioxidant, antimycobacterial activity of opuntia ficus-indica fruit (OFI) extracts were evaluated according to seasonable cultivation. The antioxidant activities of OFI extracts were assessed by different in vitro methods and the total phenolic and flavonoid contents were also examined. The antimycobacterial activity was measured against Mycobacterium tuberculosis strains H37Rv (ATCC 27294) by microplate alamar blue assay (MABA) method. In antioxidant assay, methanol extracts of OFI in summer season showed the highest antioxidant activity in all tested methods and the lowest IC50wasobservedin2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Pearson correlation coefficient was evaluated and the results from the extracts of summer and rainy season OFI were significantly correlated with the total phenolic and flavonoid contents. However, the methanol extracts of OFI in summer showed high level of antimycobacterial activity against the strain of M. tuberculosis H37Rv, with minimum inhibitory concentration (MIC) of 50 µg/ml. The results from this study suggest that OFI could probably be an important source of antioxidant as well as antimycobacterial against M. tuberculosis.
Corrosion Behavior of High Pressure Die Cast Al-Ni and Al-Ni-Ca Alloys in 3.5% NaCl Solution
( Srinivasan Arthanari ),( Jae Cheol Jang ),( Kwang Seon Shin ) 한국부식방식학회 2017 Corrosion Science and Technology Vol.16 No.3
In this investigation corrosion behavior of newly developed high-pressure die cast Al-Ni (N15) and Al-Ni-Ca (NX1503) alloys was studied in 3.5% NaCl solution. The electrochemical corrosion behavior was evaluated using open circuit potential (OCP) measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. Potentiodynamic polarization results validated that NX1503 alloy exhibited lower corrosion current density (icorr) value (5.969 μA/cm<sup>2</sup>) compared to N15 (7.387 μA/cm<sup>2</sup>). EIS-Bode plots revealed a higher impedance (|Z|) value and maximum phase angle value for NX1503 than N15 alloy. Equivalent circuit curve fitting analysis revealed that surface layer (R<sub>1</sub>) and charge transfer resistance (R<sub>ct</sub>) values of NX1503 alloy was higher compared to N15 alloy. Immersion corrosion studies were also conducted for alloys using fishing line specimen arrangement to simultaneously measure corrosion rates from weight loss (P<sub>W</sub>) and hydrogen volume (P<sub>H</sub>) after 72 hours and NX1503 alloy had lower corrosion rate compared to N15 alloy. The addition of Ca to N15 alloy significantly reduced the Al<sub>3</sub>Ni intermetallic phase and further grain refinement may be attributed for reduction in the corrosion rate.
( Thandavan Arthanari Kannan ),( Geetha Ramesh ),( S. Ushakumary ),( Gopalan Dhinakarraj ),( Subbiah Vairamuthu ) 한국동물자원과학회(구 한국축산학회) 2015 한국축산학회지 Vol.57 No.30
The present study was aimed to study the light and electron microscopic studies of thymic Hassall``s corpuscles was done in various age groups of Nandanam Chicken ranging from day-old to forty weeks. Hassall``s corpuscles are special, unique structures present in thymic medulla and also in the cortex of all the age groups of Nandanam chicken (from hatch to forty weeks) in the present study. Size of the Hassall``s corpuscles in the medulla is larger than the ones present in the cortical region of thymus. The Hassall``s corpuscles are made up of structureless eosinophilic mass surrounded by concentrically arranged reticuloepithelial cells. Under electron microscope, the Hassall``s corpuscles were composed of reticuloepithelial cells interconnected by many desmosomes. The epithelial cells had abundance of cytoplasmic fibrils and desmosomes with few mitochondria and ribosomes. The nucleus was oval or round which was slightly indented. The centre of the Hassall``s corpuscles was appeared either solid or cystic. The cystic corpuscles had cell debris within the cyst lumen.
Saravanakumar, Arthanari,Ganesh, Mani,Jayaprakash, Jayabalan,Jang, Hyun Tae Elsevier 2015 Journal of industrial and engineering chemistry Vol.28 No.-
<P><B>Abstract</B></P> <P>A single step green synthesis of silver nanoparticles (AgNPs) from silver nitrate (AgNO<SUB>3</SUB>) using <I>Cassia tora</I> leaves extract as reducing agent by a simple and ecofriendly method in room temperature. The biosynthesized nanoparticles were characterized by UV-Vis, Scanning electron microscopy (SEM) coupled with X-ray energy dispersive spectrophotometer (EDAX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). In UV-Vis spectroscopy results, the <I>λ</I> <SUB>max</SUB> observed at 425nm. The AgNPs synthesized were spherical, hexagonal and irregular in shapes. The EDAX and XRD spectrum confirms that the presence of silver ions and crystalline nature of synthesized AgNPs. FTIR showed the functional groups such as CO, NH and CN groups involved in the reduction of Ag<SUP>+</SUP> to Ag. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay was performed and it showed percentage inhibition in concentration dependent manner. The synthesized AgNPs showed antibacterial activity against <I>Escherichia coli</I>, <I>Pseudomonas aeruginosa</I>, <I>Staphylococcus aureus</I> and <I>Bacillus subtilis</I> in different extents and the higher activity was observed in <I>Escherichia coli</I>.</P>