Options
Parasuraman Selvam
Loading...
Preferred name
Parasuraman Selvam
Official Name
Parasuraman Selvam
Alternative Name
Selvam, P.
Selvam, Parasuram
Selvam, Parasuraman
Main Affiliation
Email
ORCID
Scopus Author ID
Researcher ID
Google Scholar ID
11 results
Now showing 1 - 10 of 11
- PublicationMagnesium and magnesium alloy hydrides(01-01-1986)
; ;Viswanathan, B. ;Swamy, C. S.Srinivasan, V.This review addresses the question of using magnesium and magnesium-based alloys as "rechargeable hydrogen storage" media. The effect of addition of organic compounds as well as other metals (both transition and non-transition elements) on the sorption characteristics of magnesium is considered in detail. The current status of information in this field is reviewed with a view to evaluating the potential of these materials for use as hydrogen storage media in vehicular applications. © 1986. - PublicationXPS studies of the surface properties of CaNi5(01-01-1989)
; ;Viswanathan, B.Srinivasan, V.The "air-exposed" sample of CaNi5 contains various oxygenated species on the surface. The surface properties of CaNi5 are analogous to those of LaNi5 with surface enrichment of calcium similar to lanthanum in LaNi5. © 1989. - PublicationStudies on the thermal characteristics of hydrides of Mg, Mg2Ni, Mg2Cu and Mg2Ni1-xMx (M = Fe, Co, Cu or Zn; 0 < × < 1) alloys(01-01-1988)
; ;Viswanathan, B. ;Swamy, C. S.Srinivasan, V.X-ray results on the alloys of the composition Mg2Ni1-xMx (M = Fe, Co, Cu or Zn; 0 < × < 1) suggest a Mg2Ni-type structure. The alloys, Mg2Ni0.75M0.25(M = Fe, Co, Cu or Zn) upon hydriding lead to the formation of quarternary hydrides while on dehydriding yield the starting ternary alloys except for copper containing alloys which show multi-phase regions and follow a different path way for the hydriding-dehydriding process. Thermal studies (TG-DTA) on the hydrides indicate the amount of hydrogen evolved as well as the desorption temperatures. The thermodynamic quantities, namely the enthalpies and entropies of formation of the hydrides were deduced from the DTA peak maximum temperature data. The kinetic parameters such as activation energies, reaction rates and orders of the reaction for the decomposition of the hydrides formed from Mg, Mg2Ni and Mg2Cu alloys were evaluated from the DTA data. As to the modified Mg2Ni system, the copper substituted alloys show lower thermal stability and also presents some interesting properties. Hence, it is considered as one of the promising ternary combinations (Mg-Ni-Cu) for hydrogen storage purposes. © 1988. - PublicationThermal studies on Mg2NiH4: Existence of additional hydride phase in the Mg2Ni-Hydrogen system(15-03-1988)
; ;Viswanathan, B. ;Swamy, C. S.Srinivasan, V.(TG-DTA) thermal analyses of the Mg2NiH4 system revealed the presence of another hydride phase with composition Mg2NiH. The kinetic parameters for the phase transition as well as for the decomposition of the two hydride phases have been evaluated from DTA data using temperature programmed 'Arrhenius plots'. The thermodynamic quantities, namely the enthalphy and entropy changes for the two phases, have been evaluated and compared with the data reported in the literature. © 1988. - PublicationX-ray photoelectron spectroscopic investigations of the activation of FeTi for hydrogen uptake(01-01-1987)
; ;Viswanathan, B. ;Swamy, C. S.Srinivasan, V.Activation of FeTi alloy could either give rise to surface segregation and subsequent oxidation of titanium and the formation of iron clusters or the formation of metastable TiFeO, suboxide. The validity of either of the postulates could be gauged by monitoring the nature and concentration of each of the oxidation states of iron and titanium by depth profile analysis by XPS. These studies showed that fresh samples contained multiple oxidation states of iron and titanium though the concentrations of lower valent oxides are usually small. Sputtering studies showed that this oxide layer is of considerable depth and during activation, iron oxides are easily reduced to the metallic state as compared to the oxides of titanium. The chemical reaction induced, segregation may be the contributing factor for the enhanced concentration of titanium on the surface of these alloys. © 1987. - PublicationSurface Studies of Some Hydrogen Storage Materials(01-01-1989)
; ;Viswanathan, B. ;Swamy, C. S.Srinivasan, V.XPS, XAES and AES techniques have been applied to study the surface properties of certain hydrogen storage intermetallic compounds, namely, LaNi5, CaNi5, Mg2Ni, Mg2Cu and FeTi. From these studies, it has been derived that the binary alloys undergo surface decomposition and subsequent oxidation upon exposure to air, resulting in a variety of oxygen containing species of the component elements. In addition, the surface compositions differ considerably for the various systems presented in this investigation, mainly because of their different segregation behaviours. © by R. Oldenbourg Verlag, München 1989 - PublicationMg2NiH: A new hydride phase in the Mg2NiH2 system(01-01-1988)
; ;Viswanathan, B. ;Swamy, C. S.Srinivasan, V.A new hydride phase apart from Mg2NiH4 has been identified in the Mg2NiH2 system by pressure-composition-temperature relationships, thermal analyses and X-ray diffraction measurements. The new phase has an approximate composition Mg2NiH and is considered to be the intermediate phase in the Mg2NiH2 reaction. The additional hydride phase, Mg2NiH (named as β-hydride) and the full hydride phase, Mg2NiH4 (named as γ-hydride) have been shown to crystallize in monoclinic structure. The β-phase (Mg2NiH) also exhibits a phase transition from monoclinic to cubic structure similar to the γ-phase (Mg2NiH4). © 1988. - PublicationX-ray photoelectron spectroscopic, electrical and magnetic studies on Mg2NiH4(01-01-1988)
; ;Viswanathan, B.Srinivasan, V.X-ray photoelectron and X-ray induced Auger spectroscopic (XPS and XAES) investigations show that, in Mg2NiH4, both Mg and Ni are in the metallic state. Support for this observation has been obtained from thermopower and magnetic measurements. © 1988. - PublicationSome comments on modes of activation of LaNi5 and CaNi5 alloys for hydrogen storage(01-01-1989)
; ;Viswanathan, B.Srinivasan, V.Intermetallics used for hydrogen storage purposes require prior activation. Mild activation conditions are sufficient for AB5 type intermetallics like LaNi5 and CaNi5 as compared to other intermetallics used for the purposes of hydrogen storage. In this communication a model for the activation process is proposed for the behaviour of LaNi5 and CaNi5 alloys. © 1989. - PublicationSATELLITE STRUCTURES IN THE X-RAY PHOTOELECTRON SPECTRA OF SURFACE OXIDES FORMED ON FeTi ALLOYS.(01-12-1987)
; ;Viswanathan, B. ;Swamy, C. S.Srinivasan, V.Satellite structures have been observed adjacent to the main peaks in the X-ray photoelectron spectra of metal core levels, Ti(2p) and Fe(2p), as well as in the ligand core level, O(1s), of the surface oxides present on the FeTi alloys. These satellites have been interpreted in terms of charge transfer transitions (shake-up process). The satellites of the metal and ligand tend to be mutually exclusive, a behavior that can be understood on the basis of metal-ligand overlap; this behavior gives valuable clues to the nature of metal-ligand bonding. Based on these information, the deactivation and the difficulties involved in the reactivation of FeTi alloy toward better hydrogen sorption characteristics have been considered.