198 research outputs found
Discrimination of Free Space and Subsurface Canonical Metallic Targets Using Hybrid E-Pulse Method
Abstract—Radar scattered time domain response can be modeled by natural poles using singularity expansion method (SEM) in resonance region. In this paper, limitation of the conventional Extinction pulse method is brought out, and a hybrid of conventional Extinction pulse and auto-regressive (AR) method is proposed for robust discrimination of radar targets. A new target discrimination number (TDN) is suggested, which gives very good discrimination margin for enhanced decision process. The Hybrid Extinction pulse technique is applied on the free space targets as well as subsurface canonical metallic targets and the result obtained shows good discrimination margin. The free space target response was obtained using FDTD simulation and the subsurface target response was obtained using frequency domain measurement done for the targets buried under dry sand. 1
Determination of Nonlinear Refractive Index of Zinc Phthalocyanine by Pump Induced Fizeau Interferometry
Experimental measurement of intense light induced refractive index is demonstrated using Fizeau interferometer. Refractive index is induced in a specific region of the sample with intense light pulse of a linearly polarized, Q- switched Nd:YAG laser at 1064nm wavelength. The respective change in optical path difference (OPD) is measured using Fizeau interferometer. The OPD so obtained is mapped in terms of change in refractive index in the area of interaction of pump beam and sample. The measured induced refractive index is then used to calculate thermo-optic coefficient of the ZnPc embedded polymeric sample
Dielectric Properties of Sol-gel-derived Calcium Copper Titanate andCalcium Barium Copper Titanate Thin Films
The complex perovskite compound CaCu3Ti4O12 (CCTO) is of considerable interest becauseof its anomalously large dielectric response. In this study, the dielectric properties of sol-gel-derived thin films of CCTO prepared at various annealing temperatures; 7000 °C, 7200 °C, and7500 °C have been reported. The frequency and temperature-dependent dielectric properties ofall these samples have been studied in metal-insulator-metal configuration using an impedanceanalyser. Dielectric measurements at room temperature show that the dielectric constant increaseswith the increase in annealing temperature from 700 °C–7500 °C. High dielectric constant (varyingfrom 600 to 3000 with the change in annealing temperature) has been observed at room temperatureat 100 kHz. The dielectric measurements below room temperature do not show any evidence ofstructural relaxation in CCTO except a little additional tilting of the TiO6 octahedra with decreasingtemperature. The dielectric response of Ba-doped CCTO films has also been reported
Surface Wear Studies in Some Materials Using α-induced Reactions
The radio-activity produced during the irradiation of 63,65Cu, 59Co, 93Nb and 121,123Sb targets with α-particles have been measured using activation technique. he yields of radioactive isotopic products 66,67,68 Ga, 61 Cu, 96g,mTc and 123,124,126I have been determined in the energy range ≈ 10-40 MeV using stacked foil Technique. Radioactive counting of samples was performed with a high-resolution gamma-spectrometer. As light ion beams produce an extremely narrow layer of activities in the surface of a material, these reactions may be useful for thin layer activation study
Quiescence of an Outburst of a Low-Mass Young Stellar Object: LDN1415-IRS
LDN1415-IRS, a low-mass young stellar object (YSO) went into an outburst
between 2001 and 2006, illuminating a surrounding nebula, LDN1415-Neb.
LDN1415-Neb was found to have brightened by I=3.77 mag by April 2006. The
optical light curve covering 15.5 years, starting from October 2006 to
January 2022, is presented in this study. The initial optical spectrum
indicated the presence of winds in the system but the subsequent spectra have
no wind indicators. The declining light curve and the absence of the P-Cygni
profile in later epoch spectra indicate that the star and nebula system is
retrieving back from its outburst state. Two Herbig-Haro objects (HHOs) are
positioned linearly with respect to the optical brightness peak of the nebula,
probably indicating the circumstellar disk being viewed edge-on. Our recent
deep near-infrared (NIR) imaging using TANSPEC has revealed the presence of a
nearby star-like source, south of the LDN1415-IRS, at an angular distance of
5.4 arcsec.Comment: Accepted for publication in the Journal of Astrophysics and Astronom
Genetic Diversity of Plant Growth Promoting Rhizobacteria Isolated from Rhizospheric Soil of Wheat Under Saline Condition
In this study, a total of 130 rhizobacteria was
isolated from a saline infested zone of wheat rhizosphere,
and screened for plant growth promoting (PGP) traits at
higher salt (NaCl) concentrations (2, 4, 6, and 8%). The
results revealed that 24 rhizobacterial isolates were tolerant
at 8% NaCl. Although all the 24 salt tolerable isolates
produced indole-3-acetic acid (IAA), while 10 isolates
solubilized phosphorus, eight produced siderophore, and
six produced gibberellin. However, only three isolates
showed the production of 1-aminocyclopropane-1-carboxylate
(ACC) deaminase. Diversity was analyzed through
16S rDNA-RFLP, and of these isolates with three tetra
cutter restriction enzymes (HaeIII, AluI, and MspI), the
representative cluster groups were identified by 16S rDNA
sequencing. Bacillus and Bacillus-derived genera were
dominant which showed PGP attributes at 8% NaCl concentration.
Out of 24 isolates, nitrogen fixing ability (nif H
gene) was detected in the two isolates, SU18 (Arthrobacter
sp.) and SU48
In search of a theory of supercooled liquids
Despite the absence of consensus on a theory of the transition from
supercooled liquids to glasses, the experimental observations suggest that a
detail-independent theory should exist.Comment: Commentary. 3 pages 2 figure
Prevalence and Genotypes of Mycobacterium Avium Subspecies Paratuberculosis in Large Ruminants of Eastern Uttar Pradesh, North India
Uttar Pradesh is the fourth largest, most populous and leading milk and meat producing state in India. Despite the huge livestock population, information on the status of paratuberculosis homogeneity and heterogeneity of Mycobacterium avium subspecies paratuberculosis (MAP) isolates of eastern Uttar Pradesh is non-existent. Present study was aimed to estimate the presence of MAP in large ruminants (Cattle and Buffaloes) of eastern Uttar Pradesh. A total 108 fecal samples were collected from farmer's herds of large ruminants (cattle and buffaloes) from different geographical regions (Chandauli, Mughalsarai, Gazipur, and Naugarh) of eastern Uttar Pradesh and screened for the presence of MAP infection using microscopic examination, direct IS900 PCR and culture on Herrold egg yolk (HEY) medium. The isolates recovered on HEY medium were subjected to molecular identification and genotyping using IS900 PCR and IS1311 PCR-REA method, respectively. Of the 108 fecal samples, 25 (23.14%) and 11 (10.18%) samples were positive for the presence of acid-fast bacilli and growth on HEY medium, respectively. Species-wise, 17.5, 7.5% and 26.5, 11.7% fecal samples from cattle and buffaloes were found positive for the presence of acid-fast bacilli and growth on HEY medium, respectively. Isolates recovered on HEY medium with mycobactin J were positive for IS900 sequence and genotyped as Bison Type using IS1311 PCR-REA method. Present study is the first report on the presence of MAP infection and ‘Bison Type' genotype of MAP in eastern Uttar Pradesh. These findings will be useful for the intervention of effective control measures in order to reduce the prevalence of MAP infection in domestic livestock species and prevent its spread to the human population in the regions
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