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A Sectional Matrix Method for IPT Coil Shape Optimization
Venugopal Prasanth,Pavol Bauer,J.A. Ferreira 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6
In this paper, Neumann’s integral is evaluated for computing self-inductance using a multi-turn sectional matrix method. Analytical equations are derived considering the increase in dimensions of the coil due to an impinging air-gap between the turns. The resulting sectional self-inductance matrix is computed and the concepts of sectional partial self-inductance and sectional partial mutual inductance are introduced. The effects of the various partial inductances are considered as a function of the air-gap, dimensions and turns. Further, the mutual inductance of a pair of coils is considered and the coupling is obtained analytically. The coils considered are to be used for shape optimization of IPT coils. Finally, the results are compared with experimentation. This technique being generic can be applied to a number of different polygonal shapes and can be further simplified by the theory of vector decomposition of current elements. A case study with self-inductance and perimeter as optimization objective is considered.
D.W. Maiorano,N. Venugopal,R.A. Haber 한양대학교 세라믹연구소 2007 Journal of Ceramic Processing Research Vol.8 No.4
Two variants of a nanoparticulate titania were investigated for their rheological behavior. These powders were synthesized via a sulfuric acid process, where modification of particular parameters resulted in powders varying in residual sulfate level. It was assumed that residual sulfate would affect the agglomerate structure of suspensions of these powders. These powders were washed with distilled deionized water to remove as much residual soluble sulfate as possible and the supernatant tested for sulfate level and pH. Microstructural and rheological behavior of the powders were examined as a function of number of washes. The rheological yield point was determined to increase with number of washes and in turn increase with decreased residual sulfate level. Two variants of a nanoparticulate titania were investigated for their rheological behavior. These powders were synthesized via a sulfuric acid process, where modification of particular parameters resulted in powders varying in residual sulfate level. It was assumed that residual sulfate would affect the agglomerate structure of suspensions of these powders. These powders were washed with distilled deionized water to remove as much residual soluble sulfate as possible and the supernatant tested for sulfate level and pH. Microstructural and rheological behavior of the powders were examined as a function of number of washes. The rheological yield point was determined to increase with number of washes and in turn increase with decreased residual sulfate level.
Corrosion and Nanomechanical Behaviors of 16.3Cr-0.22N-0.43C-1.73Mo Martensitic Stainless Steel
( Rahul Ghosh ),( S. Chenna Krishna ),( A. Venugopal ),( P. Ramesh Narayanan ),( Abhay K. Jha ),( P. Ramkumar ),( P. V. Venkitakrishnan ) 한국부식방식학회(구 한국부식학회) 2016 Corrosion Science and Technology Vol.15 No.6
The effect of nitrogen on the electrochemical corrosion and nanomechanical behaviors of martensitic stainless steel was examined using potentiodynamic polarization and nanoindentation test methods. The results indicate that partial replacement of carbon with nitrogen effectively improved the passivation and pitting corrosion resistance of conventional high-carbon and high- chromium martensitic steels. Post-test observation of the samples after a potentiodynamic test revealed a severe pitting attacks in conventional martensitic steel compared with nitrogen- containing martensitic stainless steel. This was shown to be due to (i) microstructural refinement results in retaining a high-chromium content in the matrix, and (ii) the presence of reversed austenite formed during the tempering process. Since nitrogen addition also resulted in the formation of a Cr<sub>2</sub>N phase as a process of secondary hardening, the hardness of the nitrogen- containing steel is slightly higher than the conventional martensitic stainless steel under tempered conditions, even though the carbon content is lowered. The added nitrogen also improved the wear resistance of the steel as the critical load (Lc2) is less, along with a lower scratch friction coefficient (SFC) when compared to conventional martensitic stainless steel such as AISI 440C.
Bandi, Venugopal,El-Khouly, Mohamed E.,Nesterov, Vladimir N.,Karr, Paul A.,Fukuzumi, Shunichi,D’Souza, Francis American Chemical Society 2013 JOURNAL OF PHYSICAL CHEMISTRY C - Vol.117 No.11
<P>Using near-IR emitting photosensitizers, viz., zinc phthalocyanine (ZnPc), zinc naphthalocyanine (ZnNc), and BF<SUB>2</SUB>-chelated azadipyrromethene (azaBODIPY), donor–acceptor conjugates have been newly formed using the well-known metal–ligand axial coordination approach. To accomplish this task, the electron-deficient azaBODIPY was functionalized to possess either two pyridine or imidazole ligating entities. The X-ray crystal structure of one such derivative revealed the presence of axial binding capable pyridine entities on the azaBODIPY macrocycle. The structural integrity of the newly formed conjugates was established from optical absorption, emission, <SUP>1</SUP>H NMR, electrochemical, and computational methods. The experimentally determined binding constants suggested moderately stable conjugates. The absence of excitation energy transfer from singlet excited azaBODIPY to either ZnPc or ZnNc in the conjugates was confirmed from the steady-state emission measurements. However, free-energy calculations suggested photoinduced electron transfer to be exothermic from singlet excited ZnPc or ZnNc to azaBODIPY. Femtosecond transient studies confirmed such predictions from where occurrence of ultrafast photoinduced electron transfer was observed. The measured rates of charge separation and charge recombination (<I>k</I><SUB>CS</SUB> and <I>k</I><SUB>CR</SUB>) revealed charge stabilization to some extent in these conjugates.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2013/jpccck.2013.117.issue-11/jp400046b/production/images/medium/jp-2013-00046b_0015.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp400046b'>ACS Electronic Supporting Info</A></P>
( Rahul Ghosh ),( A. Venugopal ),( Pradeep P I ),( L. Rama Krishna ),( P. Ramesh Narayanan ),( Bhanu Pant ),( Roy M Cherian ) 한국부식방식학회(구 한국부식학회) 2018 Corrosion Science and Technology Vol.17 No.3
AA7010 is an Al-Zn-Mg-Cu alloy containing Zr, developed as an alternate to traditional AA7075 alloy owing to their high strength combined with better fracture toughness. It is necessary to improve the corrosion resistance and surface properties of the alloy by incorporating plasma electrolytic oxidation (PEO) method. AA7010-T7452 aluminum alloy has been processed through the forging route with multi-stage working operations, and was coated with 10μm thick Al<sub>2</sub>O<sub>3</sub> ceramic aluminina coating using the plasma electrolytic oxidation (PEO) method. The corrosion, stress corrosion cracking (SCC) and nano-mechanical behaviours were examined by means of potentiodynamic polarization, slow strain rate test (SSRT) and nano-indentation tests. The results indicated that the additional thermomechanical treatment during the forging process caused a fully recrystallized microstructure, which lead to the poor environmental cracking resistance of the alloy in 3.5% NaCl solution, despite the overaging treatment. Although the fabricated PEO coating improved general corrosion resistance, the brittle nature of the coating did not provide any improvement in SCC resistance of the alloy. However, the hardness and elastic modulus of the coating were significantly higher than the base alloy.
Govindaraj Magudeeswaran,Visvalingam Balasubramanian,S.Sathyanarayanan,A. Moitra,S. Venugopal,Gankidi Madhusudhan Reddy,G. Sasikala 대한금속·재료학회 2009 METALS AND MATERIALS International Vol.15 No.6
Austenitic stainless steel, low hydrogen ferritic steel and high nickel steel consumables are used for the welding of armor-grade quenched and tempered (Q&T) steels. The use of such consumables in the welding of armorgrade Q&T steel leads to the formation of distinct microstructures in the respective welds and has a major influence on the dynamic fracture toughness. Hence, this paper examines how shielded metal arc welding consumables affect the dynamic fracture toughness (J1d) of armor-grade Q&T steel joints. The J1d values of joints fabricated with high nickel steel joints are superior than all other joints. Austenitic stainless steel, low hydrogen ferritic steel and high nickel steel consumables are used for the welding of armor-grade quenched and tempered (Q&T) steels. The use of such consumables in the welding of armorgrade Q&T steel leads to the formation of distinct microstructures in the respective welds and has a major influence on the dynamic fracture toughness. Hence, this paper examines how shielded metal arc welding consumables affect the dynamic fracture toughness (J1d) of armor-grade Q&T steel joints. The J1d values of joints fabricated with high nickel steel joints are superior than all other joints.
Balagopal, P.G.,George, N.A.,Venugopal, A.,Mathew, A.,Ahamed, M. Iqbal,Sebastian, P. Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.1
This prospective study records the tobacco related habits among the relatives of patients with advanced head and neck cancers who underwent both surgery and chemotherapy as part of their treatment from September 2009 to March 2010. A total of 200 relatives were interviewed (148 males and 52 females). 198 (99%) were aware of the fact that tobacco use can lead to cancer and 168 (84%) had any one of the habits. Smoking alone was reported in 36 (18%) individuals, pan chewing alone in 66 (33%) and multiple habits in 64 (32%). Alcohol and tobacco chewing alone was reported in one case each. There were change in habits following diagnosis of head and neck cancers among the relatives, 33 (16.5%) stopped their habits and smoking was reduced by 25% in 72 (36%)and by 50% in 63 (31.2%) individuals. However, 135 continued the habit even after the diagnosis of cancer in their relatives. Of note, 15 out of the 33 who quit the habit did it because of health advice given to them during the hospital visit.