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Dielectric properties of PbSrWO4 and PbBaWO4 compounds
No full textPbSrWO4 and PbBaWO4 have been synthesised by the solid state reaction
technique XRD patterns show them to be tetragonal. Dielectric constant (K/) and
Dielectric loss (K//) of PbSrWO4 and PbBaWO4 have been measured at 1 kHz in the
temperature range of 300 to 1050 K. The log K/ vs T as well as log K// vs T plot of
PbSrWO4 and PbBaWO4 shows rapid increase of dielectric constant above 590 K and 640
K, respectively.Author Affiliation:
S V Singh, A N Thakur, O P Singh, S C Kumar and Aqil Ahmad
1.Department of Physics, T D Post Graduate College
Jaunpur-222 002, Uttar Pradesh, India
E-mail : [email protected] of Physics, T D Post Graduate College
Jaunpur-222 002, Uttar Pradesh, Indi
Organizing Knowledge for Web Retrieval using SKOS: A Case Study in Human Protein Chain
No full textEffective knowledge management is the most
challenging task today to organize and control the millions of web resources in any scholarly publications. An effort is made to map human protein chain against different neurological disorders. After analyzing the
facets in this domain, a thesaurus is constructed, relational structure of SKOS is made and finally converted into XML:RDF compliant format for knowledge representation, manipulation, interoperability and
effective retrieval
Study of optical band gap and carbon cluster sizes formed in 100 MeV Si8+ and 145 MeV Ne6+ ions irradiated polypropylene polymer
No full textA wide variety of material modifications in polymers have been studied by using ion irradiation
techniques. Extensive research has focused on to Swift Heavy Ions (MeV's energy), probably because of good
controllability and the large penetration length in polymers. High energy ion irradiation tends to damage polymers
significantly by electronic excitation and ionization. It may result into the creation of latent tracks and can also
cause formation of radicals such as ablation, sputtering, chain scission and intermolecular cross-linking, creation
of triple bonds and unsaturated bonds and loss volatile fragments. Polypropylene polymer films of thickness 50
μm were irradiated to the fluences of 1 × 1010, 3 × 1010, 1 × 1011, 3 × 1011, 6 × 1011 and 1 × 1012 ions/cm2 with Si8+
ions of 100 MeV energy from Pelletron accelerator at Inter University Accelerator Centre (IUAC), New Delhi and
Ne6+ ions of 145 MeV to the fluences of 108, 1010, 1011, 1012 and 1013 ions/cm3 from Variable Energy Cyclotron
Centre, Kolkata. Optical modifications were characterized by UV towards the red end of the spectrum with the
increase of the fluence. Value of optical band gap Eg shows a decreasing trend with ion fluence irradiated with
both kinds of ions. Cluster size N, the number of carbon atoms per conjugation length increases with increasing
ion dose. Cluster size also increases with the increase of electronic stopping power.Rajesh Kumar1*, S Asad Ali1, A. H. Naqvi1, H. S. Virk2, Udayan De3,
D K Avasthi4 and Rajendra Prasad1
1Department of Applied Physics, Z. H. College of Engineering & Technology,
Aligarh Muslim University, Aligarh-202 002, Uttar Pradesh, India
2360 Sector-71, SAS Nagar (Mohali), Chandigarh-160 071, Punjab, India
3Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata-700 064, India
4Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi-110 067, India
E-mail : [email protected] of Applied Physics, Z. H. College of Engineering & Technology,
Aligarh Muslim University, Aligarh-202 002, Uttar Pradesh, India
2360 Sector-71, SAS Nagar (Mohali), Chandigarh-160 071, Punjab, India
Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata-700 064, India
Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi-110 067, Indi
Uranium concentration in drinking water samples using the SSNTDs
No full textUranium concentrations in the drinking water samples collected mainly from hand pumps along
the Amritsar to Bathinda track are presented. Uranium concentration values in these samples show a wide range
of variation depending upon different factors like source, location, depth and local geology etc. The observed
uranium content in water samples has been found to be varying from 0.9 ± 0.08 to 63 ± 0.21 ppb and even the
radon activity in ground water observed in our earlier survey carried out in this area has been found to be
increasing from Amritsar towards Bathinda. The higher values were observed from the ground water samples
particularly of the areas falling in belt from Zira to Maur towards the Haryana border. The values observed at
certain locations are found to be higher than the highest recommended value of 15 ppb [1]. The high uranium
concentration observed particularly in certain areas along this track can be attributed due to interaction of ground
water with the soil formation of this region and the local subsurface geology of the region.Harmanjit Singh*, Joga Singh, Surinder Singh and B S Bajwa
Department of Physics, Guru Nanak Dev University,
Amritsar-143 005, Punjab, India
E-mail : [email protected] of Physics, Guru Nanak Dev University,
Amritsar-143 005, Punjab, Indi
Evolution of phase purity and texture on annealing of BiFeO3 thin film prepared by sol-gel technique
No full textWe report preparation of phase pure BiFeO3 thin films on glass, ITO and
Si(100) substrates through chemical route using spin coating technique. Sol-gel
process was adopted to prepare the films using bismuth nitrate and iron nitrate as
precursors. X-Ray diffraction and Raman spectroscopy studies revealed amorphous
nature of the as deposited films. Rhombohedral crystalline phase of BiFeO3 evolved
on annealing the films at 500°C, but with Bi2Fe4O9 and Bi24Fe2O39 as impurity
phases. Increasing the annealing temperature to 550°C caused a drastic reduction of
the impurity phases and at 600°C, the films were phase-pure BiFeO3. Micro Raman
spectra showed features consistent with the reported characteristic peaks of BiFeO3
crystalline phase for films annealed at 500 and 550°C. Crystallite size obtained
from X-ray diffraction line width analysis are within 30 to 40 nm. Atomic force
microscopy (AFM) however showed grain size of ~192 nm, indicating polycrystalline
nature of the grains.Evolution of phase purity and texture on annealing of
BiFeO3 thin film prepared by sol-gel technique
Priyadarshini Dash1*, B N Dash2, Haripriya Rath1, Chandana Rath3 and N C Mishra1
1Department of Physics, Utkal University, Bhubaneswar-751 004, Orissa, India
2Department of Physics, SVM College, Jagatsinghpur-754 103, Orissa, India
3School of Material Science & Technology, Institute of Technology, Banaras Hindu
University, Varanasi 221 005,
Uttar Pradesh, India
E-mail: [email protected] of Physics, Utkal University, Bhubaneswar-751 004, Orissa, India
2Department of Physics, SVM College, Jagatsinghpur-754 103, Orissa, India
3School of Material Science & Technology, Institute of Technology, Banaras Hindu
University, Varanasi 221 005,
Uttar Pradesh, Indi
Analysis of diffraction efficiency of a holographic coupler with respect to angular divergence
No full textWe present a method to optimize the Coupling efficiency between two
fibers using a Holographic Coupler taking diffraction effect into account. For this
we obtain expressions for field distributions at the end facet of a fiber. The
results obtained by using the expression is found to be in good agreement with the
finite element method in literature, the small deviation is attributed to the
negligence of field in the cladding. We then use the Kogelnik theory to obtain
useful formulae suitable for diffracted optical elements. The diffraction efficiency
expressions are then used to predict the different parameters of Holograting so as
to get maximum diffraction efficiency in a direction where the field distribution
from the end facet is minimum thereby increasing the coupling efficiency.Analysis of diffraction efficiency of a holographic coupler with respect to angular
divergence
Mihir Hota and S K Tripathy*
National Institute of Science and Technology, Palur Hills, Berhampur-761 008,
Orissa, India
E-mail : [email protected] Institute of Science and Technology, Palur Hills, Berhampur-761 008,
Orissa, Indi
Reduction of background in CR-39 SSNTD using chemical pre-etching methods
No full textPresently, CR-39 Solid State Nuclear Track Detectors (SSNTD) is being
used for Fast Neutron Personnel Monitoring in India. Individual detectors are cut
manually from CR-39 sheets. Laser-cutting of the sheets will ensure precision and
also save on the laborious efforts involved in sheet cutting. It was observed that
there is a slight increase in background tracks due to laser-cutting. Studies were
carried out on the effect of chemical pre-etching at higher temperatures in
properties of CR-39 such as the background, sensitivity and minimum measurable dose.
For this purpose a pre-etch step was included in the normal processing of the CR-39
foils in an elevated temperature electrochemical cell (ETECE cell) and the duration
for pre-etch step at elevated temperature was optimized.
Samples of CR-39 exposed to dose equivalents ranging from 1 mSv to 10 mSv using
Am-Be neutron source were processed by both the methods, under normal processing
using ECE cell and in the optimized chemical pre-etch followed by normal processing.
The dose responses of CR-39 processed by both methods are compared in this paper.Reduction of background in CR-39 SSNTD using chemical pre-etching methods
Rupali Rohatgi*, Deepa Sathian, V Jayalakshmi, Sarala Nair, P K Marathe,
G Chaurasiya and S Kannan
Personnel Monitoring Section, RP & AD, Bhabha Atomic Research Centre, Mumbai-400
094, India
E-mail : [email protected] Monitoring Section, RP & AD, Bhabha Atomic Research Centre, Mumbai-400
094, Indi
Use of CR-39 films for nuclear radiation shielding efficacy evaluation of lining materials for combat vehicles
No full textAll materials provide, to a lesser or greater extent, shielding against
nuclear radiations. Armoured fighting vehicles (AFVs) have steel as the structural
material, which appears to be a reasonably good gamma and neutron shield material
but a shield of pure iron would not be equally effective against whole range of
neutron energies as it has a few resonances in electron volt range, and it reduces
energy of fast neutrons to lower energy neutrons. These neutrons will be absorbed
through radiative capture and emit gamma radiations. Thus it is essential that an
effective shield should contain a large amount of moderating material, hydrogen
being preferred with low atomic number materials (B, C, Li) and lead (Pb) to ensure
that the neutrons do not diffuse at intermediate energies in the shield as well as
gamma attenuation will also take place.
In order to have a suitable shield material for armoured vehicles which serves as
neutron and gamma radiation attenuator, polyethylene polymer with fillers lining
materials are preferred. These materials were evaluated against gamma and fast
neutrons using radioactive sources for suitability to fitment into combat vehicle as
per the requirement of protection factor values. The detector for gamma radiation
was used as Nal(Tl) while for neutron, CR-39 film was used.Use of CR-39 films for nuclear radiation shielding efficacy evaluation of lining
materials for combat vehicles
Deepak Gopalani1*, A S Jodha1, M K Das1, R K Singh2 and G L Baheti1
1Defence Laboratory, Jodhpur-342 011, Rajasthan, India
2Defence Material & Store Research & Developement Establishment, Kanpur-208 013,
Uttar Pradesh, India
E-mail : [email protected] Laboratory, Jodhpur-342 011, Rajasthan, India
2Defence Material & Store Research & Developement Establishment, Kanpur-208 013,
Uttar Pradesh, Indi
In situ radiation measurement and estimation of U/Th ratio toreflect on the uranium bearing potential zone in metamorphicrocks of Mahendragarh district, Haryana
No full textGross gamma radiation survey was carried out using Nal(Tl) scintillator
based portable gamma ray spectrometer (PGRS) around areas of Gaonri, Dholera,
Pachnota and Meghot in Mahendragarh district, Haryana. Geologically the area forms
part of north Delhi fold belt comprising calc-silicate, quartz biotite schist,
impure marble, quartzite and pegmatite rocks. Equivalent uranium (eU3O8)
concentration in ppm was estimated in situ on a regular grid pattern of 500 m (E-W)
× 1000 m (N-S) and grab samples were collected at grid locations for analyzing in
the laboratory for estimating the contents of eU3Os Raeq, ThO2 and %K. A comparison
with the laboratory analysed grab samples for eU308 data and in situ radiation
measurements shows a good match of the two sets of data. The in situ measurements
indicate higher concentration of eU3O8 in Chapra Bibipur in northeastern most
corners, Maghot area in central part, Gaonri in western part and Pachnota in
southwestern part of the study area.
As index to uranium favorability, U(Raeq).Th contour map (prepared using Surfer
software with Krieging interpolation method for this grid size) based on the data on
grab samples was generated which show three major clusters of relatively high U.Th
ratio. The blocks delineated are enriched in sodic mineral albite which support
albite hosted uranium mineralization potential in metamorphic rocks in Haryana.Author Affiliation: O P Somani, T S Sunil Kumar, B M Kukreti*, B K Bhaumik and R A Gorikhan
Atomic Minerals Directorate for Exploration and Research, Department of Atomic
Energy, West Block -7,
R K Puram, New Delhi-110 066, India
E-mail : [email protected] Minerals Directorate for Exploration and Research, Department of Atomic
Energy, West Block -7,
R K Puram, New Delhi-110 066, Indi
A comparative analysis of Mesonic, Baryonic and Glueball Regge trajectories
No full textWe present a comparative analysis of mesonic, baryonic and Glueball Regge
trajectories based on different parameters. The different inbuilt compositions of
the three seem to serve as a basis for their individual identities. We discuss
features such as crossed channel forces, signature, string models and also the
dependence of the slope of the mesons and baryons on the fine structure constant. We
infer that inspite of various inherent similarities, these three Regge trajectories
have some distinctive features which serve as a basis for their identification.Author Affiliation: Navjot Hothi and Shuchi Bisht
1.Department of Physics, Kumaun University, Nainital-263 002,
Uttrakhand, India
E-mail : [email protected] of Physics, Kumaun University, Nainital-263 002,
Uttrakhand, Indi