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Rapid visualization of latent fingerprints using novel casiO_3:sm^(3+) nanophosphors fabricated via ultrasound route

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Journal of Rare Earths 2019年第1期37卷 32-44,M0003页

作者： R.B.Basavaraj G.P.Darshan B.Daruka Prasad s.c.sharma H.Nagabhushana Prof.c.N.R.Rao centre for Advanced Materials Tumkur University Department of Physics Acharya Institute of Graduate Studies Department of Physics B M S Institute of Technology and ManagementVTU Affiliated Department of Mechanical Engineering Jain UniversityAdvisor Jain Group of Institutions

Latent fingerprints (LFPs) were the most significant identification method for individualization. Most commonly available fingerprints (FPs) in crime spot investigation were latent and patent types. Generally,LFPs were invisible and thus the effective visualization technique necessitates for the analysis of such FPs. In the past years, many traditional visualization techniques have been employed, but suffered with low resolution, sensitivity, contrast and high background noise. To overcome such limitations, we synthesized sm^(3+) doped casiO_3 nanophosphors (NPs) via an ultrasound irradiation route using mimosa pudica (m. p.)leaves extract as a bio-surfactant. The morphological behavior of the prepared samples was extensively studied by varying the concentration of the m. p. extract, ultrasound irradiation duration, pH level of the precursor solution and sonication power. The photoluminescence (PL) emission spectra exhibit characteristic peaks at～561,601 and 647 nm, which were attributed to^5G_(5/2)→~6H_J(J=5/2,7/2 and 9/2) transitions of sm^(3+) *** Judd-Ofelt(J-O) intensity parameters and other radiative properties were estimated using PL data. The commission International de I'Eclairage (cIE) color coordinates were positioned in orange-red region shows average correlated color temperature (ccT) value of～3576 K. The optimized samples can be used as a labeling agent for the visualization of LFPs on various porous and non-porous surfaces under normal light irradiation. The visualized FPs reveals well defined ridge characteristics, namely whorl, loop,arch, bifurcation, eye, island, bridge, sweat pores, etc, with high sensitivity, selectivity, low contrast and background hindrance. Aforementioned results evidence that the prepared casiO_3:sm^(3+) NPs were promising luminescent materials for solid state lighting and forensic applications.

关键词： Ultrasonication,synthesis Photoluminescence Fingerprint Photometric properties Judd-Ofelt analysis Rare earths

Exploring one material for dual applications:A red-emitting Mg_(2)GeO_(4):Eu^(3+)nanophosphor for future generation energy efficient WLEDs and dosimetric applications

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Journal of Rare Earths 2024年第10期42卷 1835-1845页

作者： Akshay Arjun G.P.Darshan s.c.sharma H.Nagabhushana D.V.sunitha H.B.Premkumar Department of Physics Faculty of Mathematical and Physical SciencesM.S.Ramaiah University of Applied SciencesBengaluru560054India Honorary Professor of Law and Forensic Materials Jain UniversityBengaluru560069India c.N.R.Rao centre for Advanced Materials Tumkur UniversityTumkur572103India school of Applied sciences(Physics) REVA UniversityBengaluru560064India

The envisaged design and developme nt of individual mate rials to excavate a broader spectrum of desired properties and offer multiple applications are highly *** this in mind,a series of forsterite-structured Mg_(2)GeO_(4):Eu^(3+)(1 mol%-9 mol%)nanophosphors was synthesized via a solution combustion method using oxalyl dihydrazide as a *** X-ray diffraction patterns confirm the orthorhombic crystal system with a Puma space *** results clearly show irregularly shaped cluster-like structures with aggregation of the *** diffuse reflectance spectra,the optical energy band gap of the Mg_(2)GeO_(4):Eu^(3+)(1 mol%-9 mol%)nanophosphors was estimated and obtained to be~4.12-4.32 *** photoluminescence emission spectra exhibit intense peaks at^(5)79,589,610,661,and 707 nm,which are due to characteristic^(5)D_(0)→^(7)F_(0),^(5)D_(0)→^(7)F_(1),^(5)Do→^(7)F_(2),^(5)D_(0)→^(7)F_(3)and^(5)D_(0)→^(7)F_(4)transitions of Eu^(3+)ions,*** commission International de L'Eclairage color coordinates are gradually tuned from pale red(0.5980,0.4012)to a pure red(0.6385,0.3611)*** glow peaks showcase excellent super-linear response at low doses ofγ-irradiations,indicating that the prepared phosphor can be used in thermoluminescent personal dosimetry which is a biological tissue *** aforementioned results demonstrate that the prepared Mg_(2)GeO_(4):Eu^(3+)(1 mol%-9 mol%)nanophosphors are considered an excellent candidate for dual applications,i.e.,red component in future generation white-light-emitting diodes(WLEDs)and personal dosimetric applications.

关键词： Nanophosphors Photoluminescence Thermoluminescence Dosimetry Photometric properties Rare earths

Flux blended synthesis of novel Y2O3：Eu^3＋ sensing arrays for highly sensitive dual mode detection of LFPs on versatile surfaces

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Journal of Rare Earths 2018年第9期36卷 954-964页

作者： K.N. Venkatachalaiah H. Nagabhushana R.B. Basavaj G.R Darshan B. Daruka Prasad s.c. sharma Department of Physics Amrito School of Engineering Amrito Vishwa Vidyapeethom Amrita University Bengoluru 560035 India Research and Development center Bharathiar University Coimbatore 641046 India Prof. c.N.R. Rao centre for Advanced Material science Tumakuru University Tumakuru 572103 India Department of Physics Acharya Institute of Graduate Studies Bangalore 560107 India Department of Physics B.M.S. Institute of Technology and Management Visveswaraya Technological University affiliated Bangalore 560064 India Honorary Professor Department of Mechanical Engineering Jain University Advisor Jain Croup of Institutions Bangalore 560069 India

In the present communication,various fluxes blended Y2 O3：Eu3＋（5 mol%） nanopowders（NPs） were successfully fabricated by solution combustion *** pattern confirms body-centered cubic structure of the prepared *** band gap（Eg） of the fabricated products was estimated and is found to be in the range of 3.13-3.32 ***（PL） emission spectra exhibit sharp and intense peaks at ～579,592,614,657,704 nm corresponding to 5 D0→7 FJ（J = 0,1,2,3 and 4） transitions of Eu3＋ *** of fluxes for enhancing the PL emissions was extensively *** studies of the prepared samples are located in pure red *** NPs were explored as a novel sensing agent for visualization of latent fingerprints（LFPs） on various surfaces including porous,semiporous and non-porous surfaces followed by powder dusting *** experiments including aging,temperature,scratching and aquatic fresh water treatment tests were performed to evaluate applicability of the fabricated *** LFPs exhibit well defined ridge details including most authenticated sweat pores are also revealed with high sensitivity,selectivity,little background hindrance and less *** results evidence that the method and fabricated NPs can be considered to be simple,rapid and economical and provide novel sensing platform for LFPs visualization in prospective forensic applications.

关键词： Fluxes Photoluminescence Latent fingerprint sweat pores Forensic applications Rare earths

Multifunctional Dy(Ⅲ)doped di-calcium silicate array for boosting display and forensic applications

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Journal of Rare Earths 2018年第7期36卷 690-702页

作者： M.Venkataravanappa R.B.Basavaraj G.P.Darshan B.Daruka Prasad s.c.sharma P.Hema Prabha s.Ramani H.Nagabhushana Department of Physics Govt.First Grade CollegeSiraTumkur 572 137India Research and Development center Bharathiar UniversityCoimbatore 641 046India Prof.cN.R.Rao centre for Advanced Materials Research Tumkur UniversityTumkur 572 103India Department of Physics Acharya Institute of Graduate StudiesBangalore 560 107India Department of Physics BMS Institute of Technology and ManagementVTU-afflliatedBangalore 560 064India Department of Mechanical Engineering Jain UniversityJain Group of InstitutionsBangalore 560 069India Avinashilingam Institute for Home science and Higher Education for Women University Coimbatore 6410 43India Department of Food Processing and Preservation Technology Avinashilingam Institute for Home Science and Higher Education for Women UniversityCoimbatore 641043India

Latent fingerprints（LFPs） are the major physical evidences for the identification of individuals during crime spot investigation. Till date, numerous methods were followed to visualize LFPs. However, simple,accurate, and cost-effective method has wide scope in advanced forensic field. In our work, ca2 siO4：Dy^（3＋）nanopowders（NPs） were fabricated via solution combustion route. The optimized sample was employed for the visualization of overlapped LFPs by the cost effective powder dusting method. The obtained results reveals the complete three levels of ridge characteristics with high sensitivity, reproducibility,selectivity, and reliability on various complex surfaces. The photoluminescence（PL） spectra consist of intense peaks at ～ 480 and 574 nm owing to ~4 F（9/2） →~6 H（15/2） and ~4 F（9/2）→~6 H（13/2） 4 f transitions of Dy3＋ ions,respectively. The photometric properties confirm that the samples exhibit intense white emission with high color purity. Therefore, the prepared NPs could be a definitive choice as an advanced luminescent NPs for forensic, solid state lighting and portable FED devices.

关键词： solution combustion Photoluminescence solid state lighting Fingerprint patterns sweat pores Rare earths

Rational design of monovalent ions （Li,Na,K） co-doped ZnAl2O4:Eu3+ nanocrystals enabling versatile robust latent fingerprint visualization

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Journal of Rare Earths 2019年第7期37卷 699-705页

作者： F.Femila Komahal H.Nagabhushana R.B.Basavaraj G.P.Darshan Hajeebaba K.Inamdar s.c.sharma B.Daruka Prasad c.N.R.Rao centre for Advanced Materials Research Tumkur UniversityTumkur-572 103India Department of Physics Acharya Institute of Graduate StudiesBangalore-560 107India Department of Physics J.B.Institute of Engineering&Technology(Autonomous)MoinabadPR.DistrictHyderabad-75India National Assessment and Accreditation council Bangalore 560 072India Department of Physics B.M.S.Institute of TechnologyVisveswaraya Technological UniversityBangalore 560064India

Alkali metal ions(M+ = Na+,Li+,K+) co-doped ZnAl2O4:Eu3+(5 mol%)(ZAE) nanopowders(NPs) were prepared via solution combustion route using Mimosa pudica(MP) leaves extract as a fuel. PXRD results of co-doped samples enhance the crystallinity and grain growth. Photoluminescence(PL) of the prepared ZAE and ZAE:M+(M+ = Na+, Li+, K+) NPs shows intense emission peaks in the range of 550-750 nm and ascribed to 5D0→7FJ(J=0-4) transitions of Eu3+ ions, respectively. A 2-fold enhancement in PL intensity was observed in Li+ co-doped samples. The optimized ZnAl2O4:Eu3+(5 mol%), Li+(1 wt%)(ZAEL)NPs were used to visualize LFPs on various porous, semi-porous and non-porous surfaces through robust powder dusting technique. The visualized latent fingerprints(LFPs) reveal well defined level 1-3 ridge characteristics under several tests such as fingerprint aging and fresh water treatment for various time durations. The obtained results clearly evidence that the prepared NPs are quite useful for multifunctional applications such as advanced forensic and solid state lightning.

关键词： Photoluminescence Latent fingerprints solid state lightning Alkali metal ions Rare earths

Mechanical behavior of organo-modified Indian bentonite nanoclay fiber-reinforced plastic nanocomposites

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Frontiers of Materials science 2013年第4期7卷 396-404页

作者： N. RAGHAVENDRA H. N. NARAsIMHA MURTHY M. KRIsHNA K. R. VIsHNU MAHEsH R. sRIDHAR s. FIRDOsH G. ANGADI s. c. sharma center for Manufacturing and Research Technology Utilization R. V. College Campus Bangalore 560059 Karnataka India Department of Mechanical Engineering R. V. College of Engineering Bangalore 560059 Karnataka India Department of chemistry ACS College of Engineering Bangalore 560074 Karnataka India Tumkur University Tumkur 572103 Karnataka India

The aim of the research was to examine the influence of organo-modified Indian bentonite （IB） nanoclay dispersed in vinyisster on the mechanical properties of nanoclaylvinylesterlglass nanocomposRes. Nanoclay was organically modified using cationic surfactant hexadecyltrimethylammonium bromide （HDTMA-Br） by cation exchange method and dispersed in vinylester using ultrasonication and twin screw extrusion. XRD of nanoclaylvinylester revealed exfoliaUon at 4 wt.% nanoclay indicating uniform dispersion in the polymer. Dsc results showed improvement in glass transition temperature by 22.3% in 4 wt.% nanoclaylvinylester/glass when compared with that of vinylester/glass. Nanoclay/vinylester/glass with 4 wt,% nanoclay showed 29.23%, 23.84% and 60.87% improvement in ultimate tensile strength （UTs）, fiexural strength （Fs） and interlaminar shear strength （ILss） respectively when compared with those of vinylester! glass. The mode of tensile failure examined by sEM showed no agglomeration of nanoclay in 4 wt.% nanoclayNinylester/glass specimens.

关键词： Indian bentonite (IB) ultrasonication twin-screw extrusion mechanical property

Mechanical, thermal and fire nanoclay/vinylester retardation behaviours of nanocomposites

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Frontiers of Materials science 2011年第4期5卷 401-411页

作者： K. R. VIsHNU MAHEsH H. N. NARAsIMHA MURTHY B. E. KUMARA sWAMY s. c. sharma R. sRIDHAR Niranjan PATTAR M. KRIsHNA B. s. sHERIGARA Department of P. G. studies and Research in Industrial chemistry Kuvempu University Shankaraghatta Shimoga 577451 Karnataka India Department of Mechanical Engineering R. V. College of Engineering Bangalore 560059 Karnataka India Tumkur University Tumkur 572103 Karnataka India

The dispersion of montmorillonite （MMT） in vinylester for preparing nanoclay/vinylester gel coat was reported. Two sets of MMT/vinylester specimens, namely Type I and Type 2, were prepared for comparative studies. Type I specimens were prepared using ultrasonication only, and Type 2 specimens were prepared using both ultrasonication and twin-screw extrusion. According to XRD and TEM results, Type 2 specimens showed lower levels of nanoclay agglomeration and higher levels o! exfoliation. Dsc results showed that the glass transition temperatures of Type 2 specimens are higher than those of Type 1 specimens. TGA results showed that the residual weight of 4 wt.% MMT/vinylester of Type 1 was 7.38%, while the corresponding value of Type 2 was 13,5%, indicating lower thermal degradation in the latter. MMTt vinylester/glass and MMT/vinylester/carbon specimens were fabricated and tested for mechanical and fire retardation behaviours. Type 2 based nanocomposite laminates showed greater values of ultimate tensile strength, flexural strength, interlaminar shear strength, impact strength, horizontal burning rate, and vertical burning rate than Type 1 based laminates. sEM images of tensile fractured surfaces revealed that Type 2 based laminates have no or less agglomeration of nanoclay than Type 1 based laminates.

关键词： twin-screw extrusion montmorillonite nanoclay nanocomposite vinylester

Environmentally assisted cracking resistance of Al-cu-Li alloy AA2195 using slow strain rate test in 3.5% Nacl solution

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Transactions of Nonferrous Metals society of china 2017年第2期27卷 241-249页

作者： R.GHOsH A.VENUGOPAL P.RAMEsH NARAYANAN s.c.sharma P.V.VENKITAKRIsHNAN Materials and Metallurgy Group Materials and Mechanical EntityVikram Sarabhai Space CentreThiruvananthapuram-695022KeralaIndia

The general corrosion and environmental cracking resistances of Al-cu-Li alloy AA2195 were investigated in 3.5% Nacl environment and compared with those of another high strength alloy AA2219. The general corrosion resistance of these alloys was examined using immersion corrosion and potentiodynamic polarization tests, while the stress corrosion cracking （scc） resistance was evaluated by slow strain rate test （ssRT） method. The tested samples were further characterized by sEM-EDs and optical profilometry to study the change in corrosion morphology, elemental content and depth of corrosion attack. The reduction in ductility was used as a parameter to evaluate the scc susceptibility of the alloys. The results indicated that the corrosion resistance of AA2195 alloy was better than that of AA2219 alloy as it exhibited lower corrosion rate, along with lower pit depth and density. However, the scc index （εNacl/εair） measured was greater than 0.90, indicating good environmental cracking resistance of both the alloys. Detailed fractography of the failed samples under sEM？EDs, in general, revealed a typical ductile cracking morphology for both the alloys.

关键词： Al-cu-Li alloy stress corrosion cracking fractography potentiodynamic polarization

Properties of cast Hiduminium/corundum Particulate composites

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Journal of Materials science & Technology 1995年第3期11卷 171-175页

作者： K.H. W. seah(Dept. of Mechanical Engineering, National University of singapore, 10 Kent Ridge crescent, singapore 0511)R.s.Kulkari and s.c.sharma (Dept. of Mechanical Engineering, R.V.college of Engineering, Mysore Road, Bangalore-560-059, Karnataka, Ind RV cOLL ENGN DEPT ENGN MECHBANGALORE 560059KARNATAKAINDIA sJcE DEPT MECH ENGNMYSOREKARNATAKAINDIA

This paper reports some results obtained in an investigation to see how increasing the corundum dispersoid content from o% to 7% in a matrix of hiduminium alloy affects the tensile and compressive strengths, the hardness and the casting characteristics of the composite. The results show that as the corundum content is increased, ultimate tensile strength (UTs)- compressive strength and hardness increase remarkably, whereas fluidity of the molten composite during casting drops significantly. It was found that just a minute amount of corundum is sufficient to cause a fairly large change in the mechanical properties and the fluidity of the molten *** drop in castability is one of the reasons why adding corundum beyond 7 percent is not recommended. If other factors are kept constant, the fluidity is seen to slightly improve if the pouring temperature of the molten metal were increased from 670 to 710℃

关键词： cast Properties of cast Hiduminium/corundum Particulate composites AsM