Cuddapah, India
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Endo T.,Mie University | Endo T.,Gifu University | Reddy L.,Svd College | Nishikawa H.,Kinki University | And 3 more authors.
Procedia Engineering | Year: 2017

This article reviews "plasma bonding" of plastic films. Polyethylene terephthalate (PET) films can be bonded directly by oxygen plasma irradiation and heat-press at low temperatures of 100-160 °C. Functional groups of COOH and OH were detected on the irradiated surface. The irradiated films were kept in the atmosphere for six years, yet they can be bonded tightly. The irradiated surface is extremely active just after the irradiation, and it is still considerably active after five years. Dry- and wet-peel tests on the bonded films suggest that there are two elements, hydrogen bonding and chemical bonding. The films are bonded weakly by these two elements at lower press temperatures due to low densities of bonds, while they are bonded strongly by high density of the pure chemical bonds at higher temperatures. The hydrogen bonding is broken by water penetration into the interface, causing smaller peel strength under the wet-peel test. FTIR results on the non-irradiated, irradiated and bonded samples indicate that COOH and OH groups are created at the surface, they are responsible for the both bondings. The OH is consumed during the heat-press bonding, then dehydrated condensation reaction can be proposed for the chemical bonding. Cross-linking layer may be the origin for the long lifetime of the irradiated active surface. © 2017 The Authors.


Udayabashakar Reddy G.,Svd College | Ramasubba Reddy R.,Svd College | Nakamura Y.,University of Tokyo | Lakshmi Reddy S.,Svd College | And 2 more authors.
Journal of Molecular Structure | Year: 2011

A holotrichite mineral sample from Corral Hollow California, USA is used in the present study. It is evident from the chemical analysis that the mineral contains FeO = 6.8, Al2O3 = 12.0, SO3 = 37.1 and H2O = 43.8 wt.%. An EPR study on powdered sample confirms the presence of manganese and iron. The optical absorption spectrum also reveals the presence of iron and manganese impurities in distorted octahedral environment. NIR results confirm the presence of water fundamentals. © 2011 Elsevier B.V. All rights reserved.


Lakshmi Reddy S.,SVD College | Padma Suvarna K.,Jawaharlal Nehru Technological University Anantapur | Udayabhaska Reddy G.,SVD College | Endo T.,Queensland University of Technology | Frost R.L.,Mie University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

Manganese minerals ardenite, alleghanyite and leucopoenicite originated from Madhya Pradesh, India, Nagano prefecture Japan, Sussex Country and Parker Shaft Franklin, Sussex Country, New Jersey respectively are used in the present work. In these minerals manganese is the major constituent and iron if present is in traces only. An EPR study of on all of the above samples confirms the presence of Mn(II) with g around 2.0. Optical absorption spectrum of the mineral alleghanyite indicates that Mn(II) is present in two different octahedral sites and in leucophoenicite Mn(II) is also in octahedral geometry. Ardenite mineral gives only a few Mn(II) bands. NIR results of the minerals ardenite, leucophoenicite and alleghanyite are due to hydroxyl and silicate anions which confirming the formulae of the minerals. © 2013 Elsevier B.V. All rights reserved.


Udayabhaskar Reddy G.,Svd College | Seshamaheswaramma K.,Svd College | Nakamura Y.,University of Tokyo | Lakshmi Reddy S.,Svd College | And 2 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012

Pyrite and chalcopyrite mineral samples from Mangampet barite mine, Kadapa, Andhra Pradesh, India are used in the present study. XRD data indicate that the pyrite mineral has a face centered cubic lattice structure with lattice constant 5.4179 Å. Also it possesses an average particle size of 91.9 nm. An EPR study on the powdered samples confirms the presence of iron in pyrite and iron and Mn(II) in chalcopyrite. The optical absorption spectrum of chalcopyrite indicates presence of copper which is in a distorted octahedral environment. NIR results confirm the presence of water fundamentals and Raman spectrum reveals the presence of water and sulfate ions. © 2012 Elsevier B.V. All rights reserved.


Reddy R.R.S.,Svd College | Reddy S.L.,Svd College | Rao P.S.,Pondicherry University | Frost R.L.,Queensland University of Technology
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2010

Optical absorption and EPR studies of the mineral tenorite, a cupric oxide which originated from Mexico and contains 54.40 wt% of CuO. EPR spectral results indicate two Cu(II) closely interacting ions to give a d2 type structure. The calculated spin Hamiltonian at room temperature and liquid nitrogen temperature is g = 2.160 and D = 125 G. The intensity of resonance line is not the same in low and high field regions. The optical absorption spectrum is due to Cu(II) in which three sets of energies indicating Cu(II) in two independent tetragonal C4v symmetry, in addition to d2 structure of octahedral coordination. The octahedral and tetragonal field parameters are compared with those reported for several other copper containing minerals. © 2009.


Reddy G.U.,Svd College | Reddy R.R.,Svd College | Reddy S.L.,Svd College | Frost R.L.,Queensland University of Technology | Endo T.,Mie University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

Pascoite mineral having yellow-orange colour of Colorado, USA origin has been characterized by EPR, optical and NIR spectroscopy. The colour dark red-orange to yellow-orange colour of the pascoite indicates that the mineral contain mixed valency of vanadium. The optical spectrum exhibits a number of electronic bands due to presence of VO(II) ions in the mineral. From EPR studies, the parameters of g, A are evaluated and the data confirm that the ion is in distorted octahedron. Optical absorption studies reveal that two sets of VO(II) is in distorted octahedron. The bands in NIR spectra are due to the overtones and combinations of water molecules. © 2011 Elsevier B.V. All rights reserved.


Reddy S.L.,Svd College | Maheswaramma K.S.,Sv University | Reddy R.R.,Svd College | Reddy A.V.,Sv University | And 4 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

A zoisite group of mineral samples from different localities are used in the present study. An EPR study on powdered samples confirms the presence of Mn(II), Fe(III) and Cr(III) in the minerals. NIR studies confirm the presence of these ions in the minerals. © 2010 Elsevier B.V. All rights reserved.


Lakshmi Reddy S.,Svd College | Reddy K.N.M.,Svd College | Siva Reddy G.,Sv University | Endo T.,Mie University | Frost R.L.,Queensland University of Technology
Molecular Physics | Year: 2010

Mottramite mineral from Tsumeb Corporation Mine, Tsumeb, Otavi, Namibia, is investigated in this present work. The mineral contains vanadium and copper contents of 22.73% and 16.84% by weight, respectively, as V2O5 and CuO. An electron paramagnetic resonance (EPR) study confirmed the presence of Cu(II) with g = 2.2. The optical absorption spectrum of mottramite indicates that Cu(II) is present in a rhombic environment. Near infrared results are due to water fundamentals. © 2010 Taylor & Francis.


Reddy T.R.,Svd College | Thyagarajan K.,Jawaharlal Nehru University | Reddy S.L.,Svd College | Endo T.,Mie University
Journal of Nanotechnology | Year: 2014

Synthesis of nano CuZnO2 compound is carried out by thermal decomposition method. The crystalline phase of the material is characterized by XRD. The calculated unit cell constants are a=3.1 and c=3.4786 and are of tetragonal structure. The unit cell constants are different from wurtzite (hexagonal) which indicate that a nanocompound is formed. Further TEM images reveal that the metal ion is in tetragonal structure with oxygen ligands. The prepared CuZnO2 is then characterized for crystallite size analysis by employing transmission electron microscopy (TEM). The size is found to be 100 nm. Uniform bright rings are noticed in the TEM picture suggesting that the nanocrystals have preferential instead of random orientations. The selected-area electron diffraction (SAED) pattern clearly indicates the formation of CuO-ZnO nanocompound. The nature of bonding is studied by electron paramagnetic resonance (EPR). The covalency character is about 0.74 and thus the compound is electrically less conductive. Optical absorption spectral studies suggest that Cu(II) is placed in tetragonal elongation crystal field. The spin-orbit coupling constant, , is calculated using the EPR and optical absorption spectral results suggest some covalent bond between metal and ligand. Near infrared (NIR) spectra are due to hydroxyl and water fundamentals. © 2014 T. Ravindra Reddy et al.


PubMed | Svd College
Type: | Journal: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy | Year: 2012

Pyrite and chalcopyrite mineral samples from Mangampet barite mine, Kadapa, Andhra Pradesh, India are used in the present study. XRD data indicate that the pyrite mineral has a face centered cubic lattice structure with lattice constant 5.4179 . Also it possesses an average particle size of 91.9 nm. An EPR study on the powdered samples confirms the presence of iron in pyrite and iron and Mn(II) in chalcopyrite. The optical absorption spectrum of chalcopyrite indicates presence of copper which is in a distorted octahedral environment. NIR results confirm the presence of water fundamentals and Raman spectrum reveals the presence of water and sulfate ions.

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