18 research outputs found
Exploring the potential of iron oxide nanoparticle embedded carbon nanotube/polyaniline composite as anode material for Li-ion cells
No full textAbstract
Transition metal oxides are being widely explored to meet the requirements of high-capacity anodes for Li-ion batteries in electric and hybrid electric vehicles. Depending on the energy storage mechanism, anode materials are classified into insertion, conversion, and alloying types. Iron oxide (Fe2O3) is a conversion-type anode material for Li-ion cells. It has drawn significant attention due to its high specific capacity (1007 mAh g−1), environmental friendliness, and the availability of simple synthesis routes. In this study, attempts are made to improve the electrical conductivity and structural stability of Fe2O3 nanoparticles by embedding them in functionalized carbon nanotubes (F-CNT)/polyaniline (PANI) network, and the resulting nanocomposite has been studied as anode material for Li-ion cells. This composite anode material is synthesized using a simple hydrothermal method and in-situ-polymerization technique. Cells assembled with Fe2O3/F-CNT/PANI as anode against Li metal in half-cell configuration are found to offer an initial discharge capacity of 1633 mAh g−1 and charge capacity of 353 mAh g−1. After 50 cycles of operation, the discharge and charge capacities are 155 mAh g−1 and 130 mAh g−1, respectively, with a Coulombic efficiency of 84% and capacity retention of 37%. Anode failure mechanism for the observed capacity fading is studied using post-mortem analysis.Abstract
Transition metal oxides are being widely explored to meet the requirements of high-capacity anodes for Li-ion batteries in electric and hybrid electric vehicles. Depending on the energy storage mechanism, anode materials are classified into insertion, conversion, and alloying types. Iron oxide (Fe2O3) is a conversion-type anode material for Li-ion cells. It has drawn significant attention due to its high specific capacity (1007 mAh g−1), environmental friendliness, and the availability of simple synthesis routes. In this study, attempts are made to improve the electrical conductivity and structural stability of Fe2O3 nanoparticles by embedding them in functionalized carbon nanotubes (F-CNT)/polyaniline (PANI) network, and the resulting nanocomposite has been studied as anode material for Li-ion cells. This composite anode material is synthesized using a simple hydrothermal method and in-situ-polymerization technique. Cells assembled with Fe2O3/F-CNT/PANI as anode against Li metal in half-cell configuration are found to offer an initial discharge capacity of 1633 mAh g−1 and charge capacity of 353 mAh g−1. After 50 cycles of operation, the discharge and charge capacities are 155 mAh g−1 and 130 mAh g−1, respectively, with a Coulombic efficiency of 84% and capacity retention of 37%. Anode failure mechanism for the observed capacity fading is studied using post-mortem analysis
Growth of thiophene based oligomers using Stille and direct arylation methods for optoelectronic applications
No full textRadiation dose due to radon and thoron progeny inhalation in high-level natural radiation areas of Kerala, India
No full text
Polyaniline Coated Curauá Fibres In Polyamide-6 Composites: The Effect Of Fibre Surface Modification On The Crystallographic Properties
No full textComposites have the ability to combine the individual properties of constitutive components, generating a unique material with properties suitable for a particular purpose. This study aims to develop a polymeric reinforced composite material, which is antistatic and light. Polyaniline (PAni) is one of the most studied conductive polymers due to its ability to exist in a large number of intrinsic redox states. The possibility of carrying out PAni synthesis on vegetable fibres and incorporating this in polymeric matrices, such as polyamide-6, enables the production of antistatic reinforced materials. In this work, curauá fibres were chemically treated with polyaniline doped with p-toluene sulfonic acid and processed with polyamide-6 in a twin-screw co-rotating and interpenetrating extruder. The microstructures of the neat curauá fibres and polyaniline coated curauá fibres were characterized by X-ray diffraction (XRD) measurements. Scanning electron microscopy was employed to observe the distribution and morphology of the PAni nanoparticles. The oxidation states of PAni were evaluated by X-ray photoelectron spectroscopy. X-ray diffraction combined with microscopy analyses of PAni synthesized without a substrate, showed crystalline components embedded into amorphous regions in the sample, while the PAni synthesized on the fibres showed a lower degree of crystallinity. The XPS analysis shows that the PAni synthesized on the fibres is in the emeraldine salt form. © 2014 WIT Press.137589598 and Experimental Measurements,International Journal of Computational Methods,WIT Transactions on the Built EnvironmentSchettini, A.R.A., Peres, R.C.D., Soares, B.G., Synthesis of polyaniline/camphor sulfonic acid in formic acid medium and their blends with polyamide-6 by in situ polymerization (2009) Synthetic Metals, 159, pp. 1491-1495Hota, P.R., Parida, R.K., Das, S.C., XRD and thermal characteristics studies of conducting polymers (2009) Journal of Reinforced Plastics and Composites, 28, pp. 265-278Araujo, J.R., Waldman, W.R., De Paoli, M.-A., Thermal properties of high density polyethylene reinforced with natural fibres: Coupling agent effect (2008) Polymer Degradation and Stability, 93, pp. 1770-1775Araujo, J.R., Mano, B., Teixeira, G.M., Spinacé, M.A.S., De Paoli, M.-A., Biocomposites of high density polyethylene reinforced with curauá fibres: Mechanical, interfacial and morphological properties (2010) Composites Science and Technology, 70, pp. 1637-1644Spinacé, M.A.S., Fermoselli, K.K.G., De Paoli, M.-A., Recycled polypropylene reinforced with curauá fibres by extrusion (2009) Journal of Applied Polymer Science, 112, pp. 3686-3694Santos, P.A., Spinacé, M.A.S., Fermoselli, K.K.G., De Paoli, M.-A., Polyamide-6/vegetal fibre composite prepared by extrusion and injection molding (2007) Composite Part A: Applied Science and Manufacturing, 28, pp. 2404-2411Araujo, J.R., Adamo, C.B., De Paoli, M.-A., Conductive composites of nylon-6 with polyaniline coated vegetal fibre (2011) Chemical Engineering Journal, 174, pp. 425-431Sengupta, P.P., Kar, P., Adhikari, B., Influence of dopant in the synthesis, characteristics and ammonia sensing behavior of processable polyaniline (2009) Thin Solid Films, 517, pp. 3770-3775MacDiarmid, A.G., Epstein, A.J., Polyanilines - A novel class of conducting polymers (1989) Faraday Discussions of the Chemical Society, 88, pp. 317-332Dutta, P., Biswas, S., De, S.K., Dieletric relaxation in polyaniline-polyvinyl alcohol composites (2002) Materials Research Bulletin, 37, pp. 193-200Rodrigues, P.C., Muraro, M., Garcia, C.M., Souza, G.P., Abbate, M., Schreiner, W.H., Gomes, M.A.B., Polyaniline/lignine blends: Thermal analysis and XPS (2001) European Polymer Journal, 37, pp. 2217-2223Schettini, A.R.A., Peres, R.C.D., Soares, B.G., Synthesis of polyaniline/camphor sulfonic acid in formic acid medium and their blends with polyamide-6 by in situ polymerization (2009) Synthetic Metals, 159, pp. 1491-1495Souza, F.G., Oliveira, G.E., Rodrigues, C.H.M., Soares, B.G., Nele, M., Pinto, J.C., Natural Brazilian Amazonic (curauá) fibres modified with polyaniline nanoparticles (2009) Macromolecular Materials and Engineering, 294, pp. 484-491Chandran, A.S., Narayanankutty, S.K., An elastomeric conducting composite based on polyaniline coated nylon fibre and chloroprene rubber European Polymer Journal, 44, pp. 2418-2429Micusik, M., Omastova, M., Prokes, J., Krupa, I., Mechanical and electrical properties of composites based on thermoplastic matrices and conductive cellulose fibres (2006) Journal of Applied Polymer Science, 101, pp. 133-142Araujo, J.R., Vallim, M.R., Spinacé, M.A.S., De Paoli, M.-A., Use of post consumer polyethylene in blends with polyamide-6: Effect of the extrusion method and compatibilizer (2008) Journal of Applied Polymer Science, 110, pp. 1310-1317Araújo, O.A., De Paoli, M.-A., Pilot plant scale preparation of dodecylbenzene sulfonic acid doped polyaniline in ethanol/water solution: Control of doping, reduction of purification time and of residues (2009) Synthetic Metals, 159, pp. 1968-1974Coelho, A.A., (2005) TOPAS - Academic Users Manual, , http://members.optusnet.com.au/~alancoelho/Roe, R.J., (2000) Methods of X-ray and Neutron Scattering In Polymer Science, , Oxford University Press., New YorkSilva, V.P.R., Silva, G.G., Caliman, V., Rieumont, J., Miranda-Pinto, C.O.B., Archanjo, B.S., Neves, B.R.A., Morphology, crystalline structure and thermal properties of PEO/MEEP blends (2007) European Polymer Journal, 43, pp. 3283-3291Warren, B.E., (1990) X-Ray Diffraction, , Dover Publications: New YorkSubramanian, K., Kumar, P., Jeyapal, P., Venkatesh, N., Characterization of ligno-cellulosic seed fibre from wrightia tinctoria plant for textile applications-an exploratory investigation (2005) European Polymer Journal, 41, pp. 853-861Nishiyama, Y., Langan, P., Chanzy, H., Crystal structure and hydrogenbonding system in cellulose Iα from synchrotron X-ray and neutron fibre diffraction (2002) Journal of American Chemical Society, 124, pp. 9074-9082Kovalenko, V.I., Crystalline Cellulose: Structure and hydrogen bonds (2010) Russian Chemical Reviews, 79, pp. 231-241Li, Z.F., Kang, E.T., Neoh, K.G., Tan, K.L., Effect of thermal processing conditions on the intrinsic oxidation states and mechanical properties of polyaniline films (1997) Synthetic Metals, 87, pp. 45-52Pan, W., Yang, S.L., Li, G., Jiang, J.M., Electrical and structural analysis of conductive polyaniline/polyacrylonitrile composites (2005) European Polymer Journal, 41, pp. 2127-2133Qaiser, A.A., Hyland, M.M., Patterson, D.A., Effects of various polymerization techniques on PAni deposition at the surface of cellulose ester microporous membranes: XPS and electrical conductivity studies (2012) Synthetic Metals, 162, pp. 958-967Chance, R., Bordeaux, D., Brédas, J.L., Silbey, R., Handbook of Conducting Polymers, 2, p. 825. , ed. Marcel Dekker Inc.: New YorkVarma, S.J., Xavier, F., Varghese, S., Jayalekshmi, S., Synthesis and studies of exceptionally crystalline polyaniline thin films (2012) Polymer International, 61, pp. 743-74
Estimation of External Dose by Car-Borne Survey in Kerala, India
No full textA car-borne survey was carried out in Kerala, India to estimate external dose. Measure-ments were made with a 3-in × 3-in NaI(Tl) scintillation spectrometer from September 23 to 27, 2013. The routes were selected from 12 Panchayats in Karunagappally Taluk which were classified into high level, mid-level and low level high background radiation (HBR) areas. A heterogeneous distribution of air kerma rates was seen in the dose rate distribution map. The maximum air kerma rate, 2.1 μGy/h, was observed on a beach sand surface. 232Th activity concentration for the beach sand was higher than that for soil and grass sur-faces, and the range of activity concentration was estimated to be 0.7–2.3 kBq/kg. The con-tribution of 232Th to air kerma rate was over 70% at the measurement points with values larger than 0.34 μGy/h. The maximum value of the annual effective dose in Karunagappally Taluk was observed around coastal areas, and it was estimated to be 13 mSv/y. More than 30% of all the annual effective doses obtained in this survey exceeded 1 mSv/y.journal articl
Crystallinity, Oxidation States And Morphology Of Polyaniline Coated Curauá Fibers In Polyamide-6 Composites
No full textPolyaniline (PAni) is one of the most studied conductive polymers due to its ability to exist in various redox states. The possibility of depositing PAni on vegetable fibers and incorporating this in polymeric matrices, such as polyamide-6, enables production of antistatic reinforced materials. In this work, polyaniline was deposited on fiber surfaces on a pilot plant scale and the composites were prepared by extrusion. The microstructures of the polyaniline coated curauá fibers and polyamide-6 were characterized by X-ray diffraction (XRD) measurements and the crystallinity degree of the polyamide-6 was evaluated by differential scanning calorimetry and XRD. Atomic force and electron scanning microscopies were employed to observe the distribution and morphology of the PAni nanoparticles. The oxidation states of PAni were determined by X-ray photoelectron spectroscopy. The results showed that polyaniline supported on the fibers presents amorphous domains and nanometer scale sizes. © 2013 Elsevier Ltd.88106112Araujo, J.R., Waldman, W.R., De Paoli, M.-A., Thermal properties of high density polyethylene reinforced with natural fibres: coupling agent effect (2008) Polym Degrad Stab, 93, pp. 1770-1775Araujo, J.R., Mano, B., Teixeira, G.M., Spinacé, M.A.S., De Paoli, M.-A., Biocomposites of high density polyethylene reinforced with curauá fibres: mechanical, interfacial and morphological properties (2010) Compos Sci Technol, 70, pp. 1637-1644Spinacé, M.A.S., Fermoselli, K.K.G., De Paoli, M.-A., Recycled polypropylene reinforced with curauá fibres by extrusion (2009) J Appl Polym Sci, 112, pp. 3686-3694Santos, P.A., Spinacé, M.A.S., Fermoselli, K.K.G., De Paoli, M.-A., Polyamide-6/vegetal fibre composite prepared by extrusion and injection molding (2007) Composites Part A, 28, pp. 2404-2411Araujo, J.R., Adamo, C.B., De Paoli, M.-A., Conductive composites of nylon-6 with polyaniline coated vegetal fibre (2011) Chem Eng J, 174, pp. 425-4316 Sengupta, P.P., Kar, P., Adhikari, B., Influence of dopant in the synthesis, characteristics and ammonia sensing behavior of processable polyaniline (2009) Thin Solid Films, 517, pp. 3770-3775Mac Diarmid, A.G., Epstein, A.J., Polyanilines - a novel class of conducting polymers (1989) Faraday Disc Chem Soc, 88, pp. 317-332Dutta, P., Biswas, S., De, S.K., Dieletric relaxation in polyaniline-polyvinyl alcohol composites (2002) Mater Res Bull, 37, pp. 193-200Rodrigues, P.C., Muraro, M., Garcia, C.M., Souza, G.P., Abbate, M., Schreiner, W.H., Polyaniline/lignin blends: thermal analysis and XPS (2001) Eur Polym J, 37, pp. 2217-2223Schettini, A.R.A., Peres, R.C.D., Soares, B.G., Synthesis of polyaniline/camphor sulfonic acid in formic acid medium and their blends with polyamide-6 by in situ polymerization (2009) Synth Met, 159, pp. 1491-1495Souza, F.G., Oliveira, G.E., Rodrigues, C.H.M., Soares, B.G., Nele, M., Pinto, J.C., Natural Brazilian Amazonic (curauá) fibres modified with polyaniline nanoparticles (2009) Macromol Mater Eng, 294, pp. 484-491Chandran, A.S., Narayanankutty, S.K., An elastomeric conducting composite based on polyaniline coated nylon fibre and chloroprene rubber (2008) Eur Polym J, 44, pp. 2418-2429Micusik, M., Omastova, M., Prokes, J., Krupa, I., Mechanical and electrical properties of composites based on thermoplastic matrices and conductive cellulose fibres (2006) J Appl Polym Sci, 101, pp. 133-142Araújo, O.A., De Paoli, M.-A., Pilot plant scale preparation of dodecylbenzene sulfonic acid doped polyaniline in ethanol/water solution: control of doping, reduction of purification time and of residues (2009) Synth Met, 159, pp. 1968-1974Warren, B.E., (1990) X-ray diffraction, , Dover Publications, New YorkCoelho, A.A., (2012), http://www.topas-academic.net/, TOPAS-Academic V4.1 Users ManualNov(1999) Polymer handbook, , Wiley Interscience, New York, [p. 126-7], J. Brandrup, E.H. Immergut, E.A. Grulke (Eds.)Roe, R.J., (2000) Methods of X-ray and neutron scattering in polymer science, , Oxford University Press, New YorkSilva, V.P.R., Silva, G.G., Caliman, V., Rieumont, J., Miranda-Pinto, C.O.B., Archanjo, B.S., Morphology, crystalline structure and thermal properties of PEO/MEEP blends (2007) Eur Polym J, 43, pp. 3283-3291Fornes, T.D., Paul, D.R., Crystallization behavior of nylon 6 nanocomposites (2003) Polymer, 44, pp. 3945-3961Murthy, N.S., Curran, S.A., Aharoni, S.M., Minor, H., Premelting crystalline relaxations and phase transitions in nylon-6 and 6,6 (1991) Macromol, 24, pp. 3215-3220Ramesh, C., Gowd, E.B., High temperature X-ray diffraction studies on the crystalline transitions in the alpha and gamma forms of nylon-6 (2001) Macromolecules, 10, pp. 3308-3313Subramanian, K., Kumar, P., Jeyapal, P., Venkatesh, N., Characterization of ligno-cellulosic seed fibre from wrightia tinctoria plant for textile applications-an exploratory investigation (2005) Eur Polym J, 41, pp. 853-861Nishiyama, Y., Langan, P., Chanzy, H., Crystal structure and hydrogen-bonding system in cellulose Iα from synchrotron X-ray and neutron fibre diffraction (2002) J Am Chem Soc, 124, pp. 9074-9082Kovalenko, V.I., Crystalline cellulose: structure and hydrogen bonds (2010) Russ Chem Rev, 79, pp. 231-241Nunes, J.P., Pouzada, A.S., Bernardo, C.A., The use of a three point support flexural test to predict the stiffness of anisotropic composite plates in bending (2002) Polym Test, 21, pp. 27-33Ding, L., Wang, X., Gregory, R.V., Thermal properties of chemically synthesized polyaniline (EB) powder (1999) Synth Met, 104, pp. 73-78Tsotcheva, D., Tsanov, T., Terlemezyan, L., Vassilev, S., Structural investigations of polyaniline prepared in the presence of dodecylbenzenesulfonic acid (2001) J Therm Anal Calor, 63, pp. 133-141Ikkalaa, O.T., Lindholmb, T.M., Ruohonenc, H., Selantausb, M., Vakipartac, K., Phase behavior of polyaniline/dodecyl benzene sulphonic acid mixture (1995) Synth Met, 69, pp. 135-136Weir, Y., Jang, G.-W., Hsueh, K.F., Scherr, E.M., MacDiarmid, A.G., Epstein, A.J., Thermal transitions and mechanical properties of films of chemically prepared polyaniline (1992) Polymer, 33, pp. 314-322Pan, W., Yang, S.L., Li, G., Jiang, J.M., Electrical and structural analysis of conductive polyaniline/polyacrylonitrile composites (2005) Eur Polym J, 41, pp. 2127-2133Jandura, P., Riedl, B., Kokta, B.V., Thermal degradation behavior of cellulose fibres partially esterified with some long chain organic acids (2000) Polym Degrad Stab, 70, pp. 387-394Basheer, R.A., Hopkins, A.R., Rasmussen, P.G., Dependence of transition temperatures and enthalpies of fusion and crystallization on composition in polyaniline/nylon blends (1999) Macromolecules, 32, pp. 4706-4712Araujo, J.R., Vallim, M.R., Spinacé, M.A.S., De Paoli, M.-A., Use of post consumer polyethylene in blends with polyamide-6: effect of the extrusion method and compatibilizer (2008) J Appl Polym Sci, 110, pp. 1310-1317Yordanov, C., Minkova, L., Fractionated crystallization of compatibilized LDPE/PA6 blend (2005) Eur Polym J, 41, pp. 527-534Villar, M.A., Marcovich, N.E., Thermal and mechanical characterization of linear low-density polyethylene/wood flour composites (2003) J Appl Polym Sci, 90, pp. 2775-2784Li, Z.F., Kang, E.T., Neoh, K.G., Tan, K.L., Effect of thermal processing conditions on the intrinsic oxidation states and mechanical properties of polyaniline films (1997) Synth Met, 87, pp. 45-52Qaiser, A.A., Hyland, M.M., Patterson, D.A., Effects of various polymerization techniques on PAni deposition at the surface of cellulose ester microporous membranes: XPS and electrical conductivity studies (2012) Synth Met, 162, pp. 958-967Chance, R., Bordeaux, D., Brédas, J.L., Silbey, R., (1986) Handbook of conducting polymers, 2. , Marcel Dekker, New York, [Chapter 24, p. 825]Varma, S.J., Xavier, F., Varghese, S., Jayalekshmi, S., Synthesis and studies of exceptionally crystalline polyaniline thin films (2012) Polym Int, 61, pp. 743-74
Radiation dose due to radon and thoron progeny inhalation in high-level natural radiation areas of Kerala, India
No full textIn order to evaluate internal exposure to radon and thoron, concentrations
for radon, thoron, and thoron progeny were measured for 259 dwellings
located in high background radiation areas (HBRAs, outdoor external dose:
3–5 mGy y−1) and low background radiation areas (control areas, outdoor
external dose: 1 mGy y−1) in Karunagappally Taluk, Kerala, India. The
measurements were conducted using passive-type radon-thoron detectors and
thoron progeny detectors over two six-month measurement periods from June
2010 to June 2011. The results showed no major differences in radon and
thoron progeny concentrations between the HBRAs and the control areas. The
geometric mean of the annual effective dose due to radon and thoron was
calculated as 0.10 and 0.44 mSv, respectively. The doses were small, but not
negligible compared with the external dose in the two areas.journal articl
The histology of brain tumors for 67 331 children and 671 085 adults diagnosed in 60 countries during 2000-2014: a global, population-based study (CONCORD-3).
No full textGlobal variations in survival for brain tumors are very wide when all histological types are considered together. Appraisal of international differences should be informed by the distribution of histology, but little is known beyond Europe and North America.
The source for the analysis was the CONCORD database, a program of global surveillance of cancer survival trends, which includes the tumor records of individual patients from more than 300 population-based cancer registries. We considered all patients aged 0-99 years who were diagnosed with a primary brain tumor during 2000-2014, whether malignant or nonmalignant. We presented the histology distribution of these tumors, for patients diagnosed during 2000-2004, 2005-2009, and 2010-2014.
Records were submitted from 60 countries on 5 continents, 67 331 for children and 671 085 for adults. After exclusion of irrelevant morphology codes, the final study population comprised 60 783 children and 602 112 adults. Only 59 of 60 countries covered in CONCORD-3 were included because none of the Mexican records were eligible. We defined 12 histology groups for children, and 11 for adults. In children (0-14 years), the proportion of low-grade astrocytomas ranged between 6% and 50%. Medulloblastoma was the most common subtype in countries where low-grade astrocytoma was less commonly reported. In adults (15-99 years), the proportion of glioblastomas varied between 9% and 69%. International comparisons were made difficult by wide differences in the proportion of tumors with unspecified histology, which accounted for up to 52% of diagnoses in children and up to 65% in adults.
To our knowledge, this is the first account of the global histology distribution of brain tumors, in children and adults. Our findings provide insights into the practices and the quality of cancer registration worldwide
Overview of the TCV tokamak experimental programme
No full textThe tokamak a configuration variable (TCV) continues to leverage its unique shaping capabilities, flexible heating systems and modern control system to address critical issues in preparation for ITER and a fusion power plant. For the 2019-20 campaign its configurational flexibility has been enhanced with the installation of removable divertor gas baffles, its diagnostic capabilities with an extensive set of upgrades and its heating systems with new dual frequency gyrotrons. The gas baffles reduce coupling between the divertor and the main chamber and allow for detailed investigations on the role of fuelling in general and, together with upgraded boundary diagnostics, test divertor and edge models in particular. The increased heating capabilities broaden the operational regime to include T (e)/T (i) similar to 1 and have stimulated refocussing studies from L-mode to H-mode across a range of research topics. ITER baseline parameters were reached in type-I ELMy H-modes and alternative regimes with 'small' (or no) ELMs explored. Most prominently, negative triangularity was investigated in detail and confirmed as an attractive scenario with H-mode level core confinement but an L-mode edge. Emphasis was also placed on control, where an increased number of observers, actuators and control solutions became available and are now integrated into a generic control framework as will be needed in future devices. The quantity and quality of results of the 2019-20 TCV campaign are a testament to its successful integration within the European research effort alongside a vibrant domestic programme and international collaborations.SP
