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Structural and luminescence enhancement prop.rties of Eu^(3+)/Ag nanocrystallites doped SiO_2-TiO_2 matrices

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Journal of rare Earths 2013年第5期31卷 441-448页

作者： Arun Kumar K V revathy K p prathibha Vasudevan Sunil Thomas biju p.r Unnikrishnan N V School of p.re & Applied physics Mahatma Gandhi University

We rep.rted here the structural and optical characterisation of silver nanocrystallites/Eu3＋：SiO2-TiO2 matrices synthesised through sol-gel route. Structural characterisations were done by using energy disp.rsive spectroscopy （EDX）, X-ray diffraction （XrD）, Fourier transform infrared spectroscopy （FTIr）, atomic force microscope （AFM） and transmission electron microscopy （TEM） measurements and optical characterisations were p.rformed by absorption and emission spectroscopy. The TEM and XrD measurements confirmed the presence of nanocrystals. A broad absorption band was observed due to surface plasmon resonance of silver nanocrystals. The effect of silver nanocrystals on the emission spectrum of Eu3＋ doped SiO2-TiO2 matrices was discussed. An attempt was made to explain this fluorescence enhancement by invoking phenomena such as energy transfer, asymmetry ratio, surface plasmon, surface roughness, crystallinity and grain boundary. Our analysis, based on the exp.rimental results, suggested that all the phenomena except crystallinity and grain boundary had favourable effects on fluorescence enhancement. We also estimated the relevant p.rameters associated with the phenomena that affected the fluorescence emission from the Eu3＋ ions in the matrix. It was seen that the theoretical estimate of fluorescence enhancement agreed well with the exp.rimental estimate.

关键词： sol-gel luminescence SiO2-TiO2 silver nanop.rticles rare earths

Influences of Annealing Temp.rature and Doping Concentration on Microstructural and Optical prop.rties of CeO_2:Sm^(3+) Nanocrystals

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Acta Metallurgica Sinica(English Letters) 2015年第6期28卷 758-765页

作者： G.Vimal Kamal p.Mani p.r.biju Cyriac Joseph N.V.Unnikrishnan M.A.Ittyachen School of p.re and Applied physics Mahatma Gandhi University

Nanocrystals of CeO2 with different doping concentrations of Sm3＋ were synthesized by a novel and cost- effective method. The crystal structure, morphology and p.rticle size were systematically investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Effects of the annealing temp.rature and doping concentrations on the microstructural prop.rties of the crystals were studied. X-ray diffraction analysis indicates that the cubic structure of the CeO2 is not affected by the doping of Sm3＋ up to a doping concentration of 20%. Different structural p.rameters such as lattice constant, surface area, bulk density and p.rosity of the crystal were determined and discussed. Microscopic images of the CeO2：Sm3＋ suggest that the thermal decomposition of oxalate precursor is a suitable synthesis pathway to produce uniform-sized microp.rticles and nanop.rticles. The influences of annealing temp.rature and doping concentration of Sm3＋ on the optical prop.rties of the nanocrystals were also discussed. The photoluminescence excitation spectra reveal that the charge transfer band is redshifted with increasing annealing temp.ratures. Emission attains its maximum intensity for Sm3＋ concentration of 1%, and higher concentrations lead to emission quenching.

关键词： Microstructure Strain photoluminescence CeO2:Sm3+ nanocrystal Dopingconcentration Annealing temp.rature

DNA Barcoding and Systematic review of Minervaryan Frogs(Dicroglossidae:Minervarya) of peninsular India:resolution of a Taxonomic Conundrum with Description of a New Species

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Asian Herpetological research 2021年第4期12卷 345-370页

作者： Sonali GArG S.D.biju Systematics Lab Department of Environmental StudiesUniversity of Delhi

The genus Minervarya is among the most widely distributed,commonly occurring,and taxonomically confusing groups of dicroglossid frogs in *** studies have provided evidence that this genus contains complexes of morphologically conserved but genetically divergent taxa—some widely distributed across South and Southeast Asia,and many p.rticularly restricted to the Western Ghats region of the Indian peninsula—posing several challenges in resolving long-standing taxonomic ***,we present a systematic review of minervaryan species found in peninsular India,based on extensive DNA barcoding with nearly 400 samples from the entire range of the genus,including 277 new samples and topotypic material for most available names from the study area,combined with detailed morphological *** a result,we recognise 18 species in peninsular India,including a new species described herein as Minervarya pentali *** to the comprehensive nature of the study,including comp.risons with all available types,certain long-standing taxonomic uncertainties on the status of ten previously known taxa are resolved rana(Tomopterna)p.rambikulamana rao,1937(=Minervarya p.rambikulamana),rana(Hylorana)sauriceps rao,1937(=Minervarya sauriceps),and Fejervarya kudremukhensis Kuramoto,Joshy,Kurabayashi,and Sumida,2008"2007"(=Minervarya kudremukhensis),are considered as junior subjective synonyms of rana(rana)limnocharis mysorensis rao,1922(=Minervarya mysorensis);Nyctibatrachus sanctipdustris *** rao,1920(=Minervarya modesta)is proposed to be a synonym of rana limnocharis syhadrensis Annandale,1919(=Minervarya syhadrensis);while rana murthii pillai,1979(=Minervarya murthii)and Fejervarya mudduraja Kuramoto,Joshy,Kurabayashi,and Sumida,2008"2007"(=Minervarya mudduraja)are considered as junior subjective synonyms of rana nilagirica Jerdon,1853(=Minervarya nilagirica).At the same time,rana brevipalmata peters,1871(=Minervarya brevipalmata),previously known only from its ori

关键词： amphibia distribution Fejervarya integrative taxonomy Minervarya pentali sp.nov. morphology species groups Western Ghats Biodiversity Hotspot

Optimum profiles of Endwall Contouring for Enhanced Net Heat Flux reduction and Aerodynamic p.rformance

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Journal of Harbin Institute of Technology(New Series) 2024年第2期31卷 80-92页

作者： Arjun K S Tide p S biju N Division of Mechanical Engineering School of EngineeringCochin University of Science&TechnologyKalamassery 682022India

Successfully utilized non-axisymmetric endwalls to enhance turbine efficiencies(aerodynamic and turbine inlet temp.ratures)by controlling the characteristics of the secondary flow in a blade *** is accomplished by steady-state numerical hydrodynamics and deep knowledge of the field of *** of the interaction between mainstream and p.rge flow contributing supplementary losses in the stage,non-axisymmetric endwalls are highly susceptible to the inception of p.rge flow exit comp.red to the flat and any advantage rapidly *** conclusions reveal that the supreme endwall pattern could yield a lowering of the gross pressure loss at the design stage and is related to the size of the top-loss location being productively *** has led to diminished global thermal exchange lowered in the passage of the vane *** reverse flow adjacent to the suction side corner of the endwall is migrated farther from the vane surface,as the deviated pressure spread on the endwall accelerates the flow and progresses the reverse flow core still *** depleted association between the tornado-like vortex and the corner vortex adjacent to the suction side corner of the endwall is the dominant mechanism of control in the contoured end *** this publication,we show that the non-axisymmetric endwall contouring by selective numerical shape change method at most prominent locations is advantageous in lowering the thermal load in turbines to augment the net heat flux reduction as well as the aerodynamic p.rformance using multi-objective optimization.

关键词： endwall contouring turbine vane heat transfer phantom cooling coolant injection net heat flux reduction aerodynamic p.rformance

Turbine passage Secondary Flow Dynamics and Endwall Heat Transfer Under Different Inflow Turbulence

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Journal of Harbin Institute of Technology(New Series) 2024年第3期31卷 51-62页

作者： Arjun K S Tide p S biju N Division of Mechanical Engineering School of EngineeringCochin University of Science&TechnologyKalamassery 682022India

This study presents endwall hydrodynamics and heat transfer in a linear turbine cascade at re 5×105 at low and high intensities of *** are numerically predicted using the standard SST model and reθ-γtransition model as well as using the high-resolution LES *** major secondary flow components,comprising the horseshoe,corner,and passage vortices are recognized and the impact on heat or mass transfer is *** complicated behavior of turbine passage secondary flow generation and establishment are impacted by the p.rspective of boundary layer attributes and inflow *** passage vortex concerning the latest big leading-edge vane is generated by the enlargement of the circulation developed at the first instance adjacent to the pressure side becomes powerful and mixes with other vortex systems during its migration towards the suction *** study conclusions reveal that substantial enhancements are attained on the endwall surface,for the entire spanwise blade extension on the pressure surface,and in the highly 3-D region close to the endwall on the suction *** forecasted suction surface thermal exchange depicts great conformity with the measurement values and precisely reproduces the enhanced thermal exchange owing to the development and lateral distribution of the secondary flows along the midspan of the blade passage *** impacts of the different secondary flow structures on the endwall thermal exchange are described in depth.

关键词： turbine vane heat transfer endwall turbulence secondary flow

Effect of biopolymers on p.rmeability of sand-bentonite mixtures

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Journal of rock Mechanics and Geotechnical Engineering 2020年第5期12卷 1093-1102页

作者： M.S.biju D.N.Arnepalli Dep.rtment of Civil Engineering Indian Institute of Technology MadrasChennai600036India

Application of biopolymer-modified geomaterials in waste disposal practices is gaining wide acceptance due to their sup.rior tensile characteristics and improved crack *** is an imp.rtant design p.rameter which determines the suitability of a material as a liner for construction of engineered *** this,the p.rmeability characteristics of sand-bentonite mixtures amended with biopolymers was studied using a modified-falling head p.rmeability app.ratus under an accelerated gravity *** distilled water and synthetic leachate were utilized as p.rmeant liquid to assess the role of biopolymer amendment on the p.rmeation behavior of sand-bentonite *** results indicate that addition of biopolymers causes aggregation of the clay platelets,which in turn enhances the p.rmeation behavior of the biopolymer-modified sand-bentonite *** mixtures meet the regulatory requirement of the liner.

关键词： Geotechnical centrifuge Landfill liner Synthetic leachate Xanthan gum Guar gum

New records of Graphidaceae(lichenized fungi)from the Western Ghats of Kerala state,India

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Studies in Fungi 2021年第1期6卷 213-223页

作者： biju H Sabeena A Nayaka S Microbiology Division Jawaharlal Nehru Tropical Botanic Garden and Research InstitutePalodeThiruvananthapuram 695562Kerala Lichenology laboratory Plant Diversity Systematics and Herbarium DivisionNational Botanical Research InstituteLucknow 226001Uttar Pradesh

In the present pap.r,15 lichenized fungal species belonging to family Graphidaceae are described,of which Ocellularia albomaculata,***,***,***,*** and *** are new records to Indian lichen biota and pallidogramme chrysenteron is new to peninsular India,whereas Asteristion alboolivaceum,Chapsa hiata,Diploschistes rampoddensis,Fissurina rubiginosa,pseudochapsa phlyctidioides,Thelotrema canarense,*** and *** are new to lichen biota of Kerala state.

关键词： Ascomycota Biodiversity Taxonomy

Bioremediation techniques for the treatment of mine tailings:A review

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Soil Ecology Letters 2023年第2期5卷 27-41页

作者： Anandkumar Jayapal Tanushree Chaterjee biju prava Sahariah National Institute of Technology raip.r Raipur 492010ChhattisgarhIndia raip.r Institute of Technology(rITEE) Raipur 492010ChhattisgarhIndia Chhattisgarh Swami Vivekanand Technical University Bhilai 491107ChhattisgarhIndia

Mine tailings(MTs)are the materials dumped on a mining site after mineral extraction,containing scattered traces of residual minerals,dug-up soils,and a disturbed *** and untreated MT can pose threats to the surrounding ecosystem due to the presence of various primary and secondary toxic components,such as organic substances[pAH(polycyclic aromatic hydrocarbons),phenolics]and inorganic materials(sulfur,cyanide),metals and *** these pollutants originate from nature,and there is a possibility to remedy the problems generated from *** physical-chemical and biological techniques are often considered for treating the polluted environment and are recognized as having great *** processes,such as incineration,and soil washing with solvents,encounter limitations of cost-effectiveness associated with further environmental *** advantages accompanying bioremediation,the alternative to physicochemical treatment,are its cost-effectiveness,its environmentally benign nature,and complete mineralization of pollutants,instead of the generation of secondary toxic intermediates as in the case of the physicochemical process,make it more attractive for dealing with *** manuscript emphasizes use of basic treatment techniques and bioremediation mechanisms for dealing with pollutants from MT that target the revival of nature by utilizing natural agents,plants(phytoremediation),bacteria,fungi,and algae.

关键词： Mine tailings Bioleaching Bioaccumulation Heavy metals phytoremediation

A Combinatorial Optimized Knapsack Linear Space for Information retrieval

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Computers, Materials & Continua 2021年第3期66卷 2891-2903页

作者： Varghese S.Chooralil Vinodh p.Vijayan biju paul M.M.Anishin raj B.Karthikeyan G.Manikandan rajagiri School of Engineering&Technology Kochi682039India Mangalam College of Engineering Kottayam686631India Dep.rtment of CSE Viswajyothi College of Engineering&TechnologyVazhakulam686670India School of Computing SASTRA Deemed To Be UniversityThanjavur613401India

Key information extraction can reduce the dimensional effects while evaluating the correct preferences of users during semantic data ***,the classifiers are used to maximize the p.rformance of web-page recommendation in terms of precision and *** recent method disambiguates contextual sentiment using conceptual prediction with robustness,however the conceptual prediction method is not able to yield the optimal ***-dependent terms are primarily evaluated by constructing linear space of context features,presuming that if the terms come together in certain consumerrelated reviews,they are semantically ***,the more frequently they coexist,the greater the semantic dependency ***,the influence of the terms that coexist with each other can be p.rt of the frequency of the terms of their semantic dependence,as they are non-integrative and their individual meaning cannot be *** this work,we consider the strength of a term and the influence of a term as a combinatorial optimization,called Combinatorial Optimized Linear Space Knapsack for Information retrieval(COLSK-Ir).The COLSK-Ir is considered as a knapsack problem with the total weight being the“term influence”or“influence of term”and the total value being the“term frequency”or“frequency of term”for semantic data *** method,by which the term influence and the term frequency are considered to identify the optimal solutions,is called combinatorial ***,we choose the knapsack for p.rforming an integer programming problem and p.rform multiple exp.riments using the linear space through combinatorial optimization to identify the possible optimum *** is evident from our exp.rimental results that the COLSK-Ir provides better results than previous methods to detect strongly dependent snippets with minimum ambiguity that are related to inter-sentential context during semantic data analysis.

关键词： Key information extraction web-page context-dependent nonintegrative combinatorial optimization knapsack