Sensing properties of polyoxomolybdate doped polyaniline nanomaterials for oxidising and reducing volatile organic compounds

P. Chithra lekha,M. Balaji,S. Subramanian,D. Pathinettam Padiyan 한국물리학회 2010 Current Applied Physics Vol.10 No.2

The polyoxomolybdates encapsulated PAni hybrid materials are prepared by interfacial polymerisation. In P12MPA, the crystal structure of 12MPA is not modified on doping with PAni. However, P11MPA have the polycrystallinity due to the presence of vanadium in the dopant molecule. Though, the hybrids prepared by interfacial polymerisation are in emaraldine salt form, there is a blue shift in the absorption spectra due to dopant induced decrease in conjugation length and over-oxidation. Interfacially polymerised PAniPOM hybrid materials are exposed with various concentrations of vapours of different volatile organic compounds (VOC) such as acetone, methanol, chloroform and carbon tetrachloride. The oxidising VOCs like acetone and methanol on exposure to PAni decrease the resistivity by hydrogen bonding with the redox cites of the polymer. Among these two, the sensitivity towards acetone is more in PAni and its hybrids which can be linked with the vapour pressure of the analyte. Due to the weak acidic characteristics of chlorinated hydrocarbons which are reducing vapours, the resistivity of PAni and its hybrids increases on exposure to chloroform and CCl4. Here, the chlorinated hydrocarbons interact with the redox sites of PAni and reduce it to base form. Bridging of polymer chains is also proposed for the reduction of conductivity on exposure to the analyte. The sensitivity is higher for the reducing analytes than that of the oxidising one.

Experimental investigation on the hysteresis behavior of the wire rope isolators

P. S. Balaji,Leblouba Moussa,M. E. Rahman,Loo Tshun Vuia 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.4

Vibration isolation has been widely applied to filter the external excitation energy and impact forces in building structures and equipment. Wire rope isolator (WRI), a kind of isolator for vibration and shock isolation, shows a better performance in attenuating theseforces. WRIs are able to deviate these external forces through their mechanical configuration and high-energy dissipative capabilities. The application of WRI demands knowledge of its behavior and the relation between various geometrical properties and input force. Thepresent work investigates the influence of geometrical parameters, such as wire rope diameter, number of coils, and displacement amplitudeon the hysteresis behavior of WRI under quasi-static loading in both vertical and horizontal directions. The hysteresis behavior ofdifferent WRIs was evaluated using the calculated parameters from hysteresis force-displacement curves: energy loss ratio (ELR), andeffective stiffness. The study indicates that the geometric properties significantly influence the effective stiffness than the energy lossratio. It is observed that, increased displacement amplitude results in decreased ELR and hence damping capabilities. The study alsoconfirms that the wire rope isolator possesses a good ability in damping through its stiffness and high-energy dissipation capability.

Electronic structure studies of nanoferrite Cu(x)Co(1-x)Fe2O4 by X-ray absorption spectroscopy.

Gautam, S,Muthurani, S,Balaji, M,Thakur, P,Padiyan, D Pathinettam,Chae, K H,Kim, S S,Asokan, K American Scientific Publishers 2011 Journal of Nanoscience and Nanotechnology Vol.11 No.1

<P>Pure and mixed cobalt copper ferrites are of great interest due to their widespread application in electronics and medicine. We report on the electronic structure of a nanoferrite Cu(x)Co(1-x)Fe2O4 (0.0 < or = x < or = 1.0) system studied by X-ray absorption spectroscopy. These magnetic nanoferrites (average crystallite size approximately 31-43 nm) were synthesized by an auto combustion method and are characterized by high resolution X-ray diffraction and near edge X-ray absorption fine structure measurements at the O K and Co, Cu, and Fe L-edges. The O K-edge spectra suggest that there is a strong hybridization between O 2p and 3d electrons of Co, Cu and Fe cations and Fe L3,2-edge spectra indicate that Fe ions coexist in mixed valence states (Fe3+ and Fe2+) at tetrahedral and octahedral sites of the spinel structure. Copper and cobalt ions are distributed in the divalent state in octahedral sites of the spinel structure. The origin of high saturation magnetization and coercivity in cobalt-copper ferrites are explained in light of these results.</P>

An analytical study on the static vertical stiffness of wire rope isolators

P. S. Balaji,Leblouba Moussa,M. E. Rahman,Lau Hieng Ho 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.1

The vibrations caused by earthquake ground motions or the operations of heavy machineries can affect the functionality of equipmentand cause damages to the hosting structures and surrounding equipment. A Wire rope isolator (WRI), which is a type of passive isolatorknown to be effective in isolating shocks and vibrations, can be used for vibration isolation of lightweight structures and equipment. Theprimary advantage of the WRI is that it can provide isolation in all three planes and in any orientation. The load-supporting capability ofthe WRI is identified from the static stiffness in the loading direction. Static stiffness mainly depends on the geometrical and materialproperties of the WRI. This study develops an analytical model for the static stiffness in the vertical direction by using Castigliano’s secondtheorem. The model is validated by using the experimental results obtained from a series of monotonic loading tests. The flexuralrigidity of the wire ropes required in the model is obtained from the transverse bending test. Then, the analytical model is used to conducta parametric analysis on the effects of wire rope diameter, width, height, and number of turns (loops) on vertical stiffness. The wire ropediameter influences stiffness more than the other geometric parameters. The developed model can be accurately used for the evaluationand design of WRIs.

Role of Liquid Metal in Flexible Electronics and Envisage with the Aid of Patent Landscape: A Conspicuous Review

P. Gowtham,S. K. B. Pradeepkumar Ch,Pidatala Prabhakara Sharma,D. Balaji 대한금속·재료학회 2023 ELECTRONIC MATERIALS LETTERS Vol.19 No.4

Wearable's become most widely used in the medical field to assess and monitor human body conditions even from remotelocations. So, it should be weightless as well as functional at various temperature ranges. It is mandated that it should befunctional with ultra-sensitiveness. The proper selection of conductive elements should be part of the measuring device. Based on these criteria, this review article is articulated. The effect conductor is metal, but metal is heavier, wearable shouldbe slick thereby, the best material is liquid metal. So, the scope and implications of the liquid metal in flexible electronicsare consolidated. Furthermore, the future scope of the wearable is assessed with the aid of patent landscape analysis, as aknown fact is updated faster than other databases. As well-identified few technologies that have been applied as patents, itmight have better growth owing to its technological advancements.

High-energy ion induced physical and surface modifications in antimony sulphide thin films

S. Subramanian,M. Balaji,P. Chithra Lekha,K. Asokan,D. Kanjilal,Indra Sulania,Jai Prakash,D. Pathinettam Padiyan 한국물리학회 2010 Current Applied Physics Vol.10 No.4

Sb2S3 thin films prepared by electrodeposition on indium tin oxide coated glass substrate were irradiated with 150 MeV Ni11+ ions for various fluence in the range of 1011–1013 ions/㎠. The modifications in the structure, surface morphology and optical properties have been studied as a function of ion fluence. X-ray diffraction (XRD) analysis indicates a shift in the (2 4 0) peak position towards lower diffraction angle and a decrease in grain size with increase in ion fluence. Presence of microcracks due to irradiation induced grain splitting effect has been observed from the SEM micrograph at higher ion fluence. The optical absorbance spectrum revealed a shift in the fundamental absorption edge and the band gap energy increased from a value of 1.63 eV for as-deposited films to 1.80 eV for the films irradiated with 1013 ions/㎠.

Prediction of negative peak wind pressures on roofs of low-rise building

K. Balaji Rao,M.B. Anoop,P. Harikrishna,S. Selvi Rajan,Nagesh R. Iyer 한국풍공학회 2014 Wind and Structures, An International Journal (WAS Vol.19 No.6

In this paper, a probability distribution which is consistent with the observed phenomenon at the roof corner and, also on other portions of the roof, of a low-rise building is proposed. The model is consistent with the choice of probability density function suggested by the statistical thermodynamics of open systems and turbulence modelling in fluid mechanics. After presenting the justification based on physical phenomenon and based on statistical arguments, the fit of alpha-stable distribution for prediction of extreme negative wind pressure coefficients is explored. The predictions are compared with those actually observed during wind tunnel experiments (using wind tunnel experimental data obtained from the aerodynamic database of Tokyo Polytechnic University), and those predicted by using Gumbel minimum and Hermite polynomial model. The predictions are also compared with those estimated using a recently proposed non-parametric model in regions where stability criterion (in skewness-kurtosis space) is satisfied. From the comparisons, it is noted that the proposed model can be used to estimate the extreme peak negative wind pressure coefficients. The model has an advantage that it is consistent with the physical processes proposed in the literature for explaining large fluctuations at the roof corners.

Prediction of negative peak wind pressures on roofs of low-rise building

Rao, K. Balaji,Anoop, M.B.,Harikrishna, P.,Rajan, S. Selvi,Iyer, Nagesh R. Techno-Press 2014 Wind and Structures, An International Journal (WAS Vol.19 No.6

In this paper, a probability distribution which is consistent with the observed phenomenon at the roof corner and, also on other portions of the roof, of a low-rise building is proposed. The model is consistent with the choice of probability density function suggested by the statistical thermodynamics of open systems and turbulence modelling in fluid mechanics. After presenting the justification based on physical phenomenon and based on statistical arguments, the fit of alpha-stable distribution for prediction of extreme negative wind pressure coefficients is explored. The predictions are compared with those actually observed during wind tunnel experiments (using wind tunnel experimental data obtained from the aerodynamic database of Tokyo Polytechnic University), and those predicted by using Gumbel minimum and Hermite polynomial model. The predictions are also compared with those estimated using a recently proposed non-parametric model in regions where stability criterion (in skewness-kurtosis space) is satisfied. From the comparisons, it is noted that the proposed model can be used to estimate the extreme peak negative wind pressure coefficients. The model has an advantage that it is consistent with the physical processes proposed in the literature for explaining large fluctuations at the roof corners.

Methodologies for numerical modelling of prestressed concrete box-girder for long term deflection

M.C. Lalanthi,P. Kamatchi,K. Balaji Rao,S. Saibabu 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.21 No.3

In this paper, two methods M1 and M2 to determine long-term deflection through finite element analyses including the effect of creep and relaxation are proposed and demonstrated for a PSC box-girder. In both the methods, the effect of creep is accounted by different models from international standards viz., ACI-209R-92, CEB MC 90-99, B3 and GL2000. In M1, prestress losses due to creep and relaxation and age adjusted effective modulus are estimated through different models and have been used in finite element (FE) analyses for individual time steps. In M2, effects of creep and relaxation are implemented through the features of FE program and the time dependent analyses are carried out in single step. Variations in time-dependent strains, prestress losses, stresses and deflections of the PSC box-girder bridge through M1 and M2 are studied. For the PSC girder camber obtained from both M1 and M2 are lesser than simple bending theory based calculations, this shows that the camber is overestimated by simple bending theory which may lead to non-conservative design. It is also observed that stresses obtained from FEM for bottom fibre are lesser than the stresses obtained from bending theory at transfer for the PSC girder which may lead to non-conservative estimates.

Whole Body Vibration Impact Assessment on Dumper Operator Using Computational Learning Technique

Kaviraj Ramar,L. A. Kumaraswamidhas,P. S. Balaji,A. Agasthian 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.2

In the mining industry, the dumper vehicle plays a vital role in material handling tasks. During the various operations, the dumper operators are subjected to whole-body vibrations (WBV) which also affects their physiological factors. The present study investigates the dumper operator discomfort during various dumper operations such as material-loading (ML), loaded-travel (LT), material-unloading (MU) and unloaded-travel (UT). As per ISO 2631:1 specified, limit during the ML and MU task, the measured crest factor value is greater than the recommended values. However, the measured aw(8) and VDV(8) magnitude are within the specified limit. In the LT, it is observed that the VDV is within the limit, although the measured value is 1.39 times greater than MU task. The maximum WBV is observed during the UT, and the measured value of VDV falls above the specified limit, and experience a greater amplification of source vibration at 1.6 Hz. Moreover, the demand for high number of operation cycle increases the risk of neck pain and back pain among the study population. Operator physiological stress under WBV exposure showed a significant increase in heart rate by 2.04 bpm. Whereas, no significant influence on the increase in blood pressure (SYS/DIA: 1.56/0.76 mmHg) and a decrease in oxygen saturation level (SpO2) by 1% was observed. Therefore, to optimize the performance of seat design under different operation cycle using computational learning technique support vector machine classifier with quadratic preset model provides a best accuracy of 98.5% over the other machine learning algorithm. The study reveals that the prolonged sitting and constant experience of WBV could increase the job work stress, the computational learning technique warranted to prevent the operator from high WBV exposures.