INTEGRATED RATE SPACE ∫ ℓ_π

Subramanian, N.,Rao, K. Chandrasekhara,Gurumoorthy, N. Korean Mathematical Society 2007 대한수학회논문집 Vol.22 No.4

This paper deals with the BK-AK property of the integrated rate space ${\int}{\ell}_{\pi}$. Importance of ${\delta}^{(k)}$ in this content is pointed out. We investigate a determining set for the integrated rate space ${\int}{\ell}_{\pi}$. The set of all infinite matrices transforming ${\int}{\ell}_{\pi}$, into BK-AK space Y is denoted $({\int}{\ell}_{\pi}:\;Y)$. We characterize the classes $({\int}{\ell}_{\pi}:\;Y)$. When $Y={\ell}_{\infty},\;c_0,\;c,\;{\ell}^p,\;bv,\;bv_0,\;bs,\;cs,\;{\ell}_p,\;{\ell}_{\pi}$. In summary we have the following table:

Seismic performance of lateral load resisting systems

Subramanian, K.,Velayutham, M. Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.51 No.3

In buildings structures, the flexural stiffness reduction of beams and columns due to concrete cracking plays an important role in the nonlinear load-deformation response of reinforced concrete structures under service loads. Most Seismic Design Codes do not precise effective stiffness to be used in seismic analysis for structures of reinforced concrete elements, therefore uncracked section properties are usually considered in computing structural stiffness. But, uncracked stiffness will never be fully recovered during or after seismic response. In the present study, the effect of concrete cracking on the lateral response of structure has been taken into account. Totally 120 cases of 3 Dimensional Dynamic Analysis which considers the real and accidental torsional effects are performed using ETABS to determine the effective structural system across the height, which ensures the performance and the economic dimensions that achieve the saving in concrete and steel amounts thus achieve lower cost. The result findings exhibits that the dual system was the most efficient lateral load resisting system based on deflection criterion, as they yielded the least values of lateral displacements and inter-storey drifts. The shear wall system was the most economical lateral load resisting compared to moment resisting frame and dual system but they yielded the large values of lateral displacements in top storeys. Wall systems executes tremendous stiffness at the lower levels of the building, while moment frames typically restrain considerable deformations and provide significant energy dissipation under inelastic deformations at the upper levels. Cracking found to be more impact over moment resisting frames compared to the Shear wall systems. The behavior of various lateral load resisting systems with respect to time period, mode shapes, storey drift etc. are discussed in detail.

Investigations on the structural, optical and electronic properties of Nd doped ZnO thin films

Subramanian, M,Thakur, P,Gautam, S,Chae, K H,Tanemura, M,Hihara, T,Vijayalakshmi, S,Soga, T,Kim, S S,Asokan, K,Jayavel, R Institute of Physics [etc.] 2009 Journal of Physics. D, Applied Physics Vol.42 No.10

<P>We report the synthesis and characterization of Nd doped ZnO thin films grown on Si (1 0 0) substrates by the spray pyrolysis method. The surface morphology of these thin films was investigated by scanning electron microscopy and shows the presence of randomly distributed structures of nanorods. Grazing angle x-ray diffraction studies confirm that the doped Nd ions occupied Zn sites and these samples exhibited a wurtzite hexagonal-like crystal structure similar to that of the parent compound, ZnO. The micro-photoluminescence measurement shows a decrease in the near band edge position with Nd doping in the ZnO matrix due to the impurity levels. The near-edge x-ray absorption fine structure (NEXAFS) measurements at the O K edge clearly exhibit a pre-edge spectral feature which evolves with Nd doping, suggesting incorporation of more charge carriers in the ZnO system and the presence of strong hybridization between O 2p–Nd 5d orbitals. The Nd M<SUB>5</SUB> edge NEXAFS spectra reveal that the Nd ions are in the trivalent state.</P>

Seismic performance of lateral load resisting systems

K. Subramanian,M. Velayutham 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.51 No.3

In buildings structures, the flexural stiffness reduction of beams and columns due to concrete cracking plays an important role in the nonlinear load-deformation response of reinforced concrete structures under service loads. Most Seismic Design Codes do not precise effective stiffness to be used in seismic analysis for structures of reinforced concrete elements, therefore uncracked section properties are usually considered in computing structural stiffness. But, uncracked stiffness will never be fully recoveredduring or after seismic response. In the present study, the effect of concrete cracking on the lateral response of structure has been taken into account. Totally 120 cases of 3 Dimensional Dynamic Analysis which considers the real and accidental torsional effects are performed using ETABS to determine the effective structural system across the height, which ensures the performance and the economic dimensions that achieve the saving in concrete and steel amounts thus achieve lower cost. The result findings exhibits that the dual system was the most efficient lateral load resisting system based on deflection criterion, as they yielded the least values of lateral displacements and inter-storey drifts. The shear wall system was the most economical lateral load resisting compared to moment resisting frame and dual system but they yielded the large values of lateral displacements in top storeys. Wall systems executes tremendous stiffness at the lower levels of the building, while moment frames typically restrain considerable deformations and provide significant energy dissipation under inelastic deformations at the upper levels. Cracking found to be more impact over moment resisting frames compared to the Shear wall systems. The behavior of various lateral load resisting systems with respect to time period, mode shapes, storey drift etc. are discussed in detail.

Neural network based modeling of infilled steel frames

K. Subramanian,K. M. Mini,S. Josephine Kelvina Florence 국제구조공학회 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.21 No.5

Leader-following Consensus of Nonlinear Multi-agent Systems via Reliable Control with Time-varying Communication Delay

K. Subramanian,P. Muthukumar,주영훈 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.2

This paper investigates the consensus problem of continuous-time leader-following nonlinear multi-agentsystems with time-varying communication delay via reliable control. The parameter uncertainty is assumed to bebounded in given compact sets. With certain assumptions on the dynamic nonlinearity and underlying topology,the sufficient conditions are derived in terms of linear matrix inequality (LMI) by using a suitable Lyapunov-Krasovskii functional (LKF). It is ensure that the leader-following consensus can be achieved under the proposedreliable control scheme. Finally, numerical simulation results are presented to demonstrate the theoretical results.

THE ORIGIN OF LARGE SCALE GALACTIC MAGNETIC FIELDS

SUBRAMANIAN K. The Korean Astronomical Society 1996 Journal of The Korean Astronomical Society Vol.29 No.suppl1

Magnetic fields correlated on several kiloparsec scales are seen in spiral galaxies. Their origin could be due to the winding up of a primordial cosmological field or due to amplification of a small seed field by a turbulent galactic dynamo. Both options have difficulties: There is no known battery mechanism for producing the required primordial field. Equally the turbulent dynamo may self destruct before being able to produce the large scale field, due to excess generation of small scale power. The current status of these difficulties is discussed. The resolution could depend on the nature of the saturated field produced by the small scale dynamo. We argue that the small scale fields do not fill most of the volume of the fluid and instead concentrate into intermittent ropes, with their peak value of order equipartition fields, and radii much smaller than their lengths. In this case these fields neither drain significant energy from the turbulence nor convert eddy motion of the turbulence on the outer scale to wave like motion. This preserves the diffusive effects needed for the large scale dynamo operation.

Neural network based modeling of infilled steel frames

Subramanian, K.,Mini, K.M.,Josephine Kelvina Florence, S. Techno-Press 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.21 No.5

A neural network based model is developed for the structural analysis of masonry infilled steel frames, which can account for the non-linearities in the material properties and structural behaviour. Using the data available from the analytical methods, an ANN model with input parameters consisting of dimension of frame, size of infill, properties of steel and infill was developed. It was found to be acceptable in predicting the failure modes of infilled frames and corresponding failure load subject to limitations in the training data and the predicted results are tested using the available experimental results. The study shows the importance of validating the ANN models in simulating structural behaviour especially when the data are limited. The ANN model was also compared with the available experimental results and was found to perform well.

X-ray Absorption and Emission Study of Co-doped ZnO Thin Films

K. H. Chae,S. Gautam,J. H. Song,M. Subramanian,R.Jayavel,K. Asokan 한국진공학회 2009 한국진공학회 학술발표회초록집 Vol.37 No.-

Visible light active pristine and Fe³⁺ doped CuGa₂O₄ spinel photocatalysts for solar hydrogen production

Gurunathan, K.,Baeg, J.-O.,Lee, S.M.,Subramanian, E.,Moon, S.-J.,Kong, K.-j. Pergamon Press ; Elsevier Science Ltd 2008 International journal of hydrogen energy Vol.33 No.11

Spinel metal oxide photocatalysts, a rarely studied group in visible light driven photocatalytic decomposition of H<SUB>2</SUB>S and solar H<SUB>2</SUB> production, have been investigated in the present work. d<SUP>10</SUP> p-block element, Ga containing spinel CuGa<SUB>2</SUB>O<SUB>4</SUB> in pristine and Fe<SUP>3+</SUP>doped (CuGa<SUB>2-x</SUB>Fe<SUB>x</SUB>O<SUB>4</SUB>, x=0.6) states, was prepared by ceramic route without/with noble metal oxide, NiO/RuO<SUB>2</SUB> loading to the extent of 1wt%. XRD analysis reveals a single-phase cubic spinel crystalline structure for all the catalysts. FESEM displays an irregular-shaped grain morphology for CuGa<SUB>2</SUB>O<SUB>4</SUB> and smaller size almost cubic particles for CuGa<SUB>2-x</SUB>Fe<SUB>x</SUB>O<SUB>4</SUB>. Energy dispersive X-ray spectroscopy suggests a chemical composition consistent with the stoichiometric molecular formula. Optically, the catalysts display an intensive light absorption in UV and visible regions with an onset at about 900nm in the near IR region. Fe<SUP>3+</SUP> doping constructively influences the morphology and optical properties of pristine CuGa<SUB>2</SUB>O<SUB>4</SUB>. All these physico-chemical and material characteristics infuse a facile catalytic function into the prepared spinel oxides such that the naked CuGa<SUB>2</SUB>O<SUB>4</SUB> and CuGa<SUB>2-x</SUB>Fe<SUB>x</SUB>O<SUB>4</SUB> spinels exhibit a moderate to fairly good photocatalytic activity while the co-catalyst-loaded CuGa<SUB>2-x</SUB>Fe<SUB>x</SUB>O<SUB>4</SUB> spinel performs an exceedingly good photocatalytic activity with 15% quantum efficiency. Thus, the present work leads to the emergence of functionally high performance, stable and visible active (λ>=420nm) photocatalysts in the spinel group for the production of solar hydrogen from H<SUB>2</SUB>S.