215 research outputs found
Characterization of Printed Podal Vivaldi Antenna (8–18 GHz) on RT Duroid with Single and Double Cavity
In today’s modern communication systems, miniaturized and lightweight subsystems covering broad bandwidth are in much demand as they lead to realization of very compact and lightweight systems. A printed podal Vivaldi antenna with single as well as double cavities fed with strip line transmission line and operating from X band to KU band (8–18 GHz) is proposed. The comparison of antenna performance for single cavity and double cavity is also reported. Using double cavity, the miniaturization of antenna is possible as compared to single cavity Vivaldi antenna. The antenna is first designed using conventional theoretical approaches. Later, it is simulated using a 3D EM simulation software, CST Microwave StudioTM. The optimal value for taper length is 6.86455 cm and cavity diameter is 1.582 cm. Finally, the design is physically fabricated using PCB technology for carrying out practical measurement. The antenna’s input impedance characteristic is measured in the form of S-parameter and VSWR using Vector network analyzer. VSWR less than 3:1 is achieved over the band from 8 to 18 GHz. The radiation pattern measurements are carried out in anechoic chamber. The proposed Vivaldi antenna is used for digital data transmission via satellites and for voice/audio transmissions
Two Generational Study on the Effect of Different Levels of Fluoride on Rat Bone and Teeth
The effects of different levels of fluoride in drinking water on different parameters of femurs and incisors of female rats were studied. Rats and their offspring, before and after weaning, were used for the study. Mother rats received 0, 1 and 5 ppm fluoride in drinking water. After weaning, the offspring were given the following treatments: 0-0, 0-1, 0-5, 1-0, 1-1, 1-5, 5-0, 5-1 and 5-5; the first number indicating fluoride level of mother\u27s water during mating, pregnancy and lactation and the second number indicating the fluoride level of water given to the offspring. Femurs and top and bottom incisors were collected from mother rats, 21 day old pups and 300g. body weight pups. Femurs were analysed for ash, calcium, phosphorus and fluoride content and breaking strength. Only fluoride analyses were done on incisors. Fluoride ion electrodes (Orion models 94-09 and 96-09) were used for fluoride analysis.
Mother rats that received 1 and 5 ppm of fluoride showed on increase in fluoride content of teeth. There was no increase in the fluoride content of weanling rat teeth suggesting that there was no maternal transfer of fluoride to the offspring.
A significant increase in fluoride content of femur and teeth of all the groups of 300g. offspring, that received 1 and 5 ppm of fluoride, was observed as compared to the control group (0-0). No significant differences in other femur parameters of 300 g. offspring were observed.
Significant differences in fluoride content of femurs and incisors of 300g. rat offspring were found due to pre and post-weaning fluoride treatments. Combined pre and post-weaning fluoride administration resulted in higher fluoride content of femurs and incisors.
At the levels used in this study, pre-weaning fluoride administration alone does not appear to affect the fluoride content of bone and teeth of the rat offspring, but fluoride, when given ofter weaning does contribute to the increased fluoride content of bone and teeth
The role of the project manager as a champion of construction innovation
Master'sMASTER OF SCIENCE (BUILDING
Weyl Metal Phase in Delafossite Oxide PtNiO
On the basis of density functional theory calculations we predict Weyl points
in rhombohedral structure of PtNiO having symmorphic symmetry. From the
formation energy and phonon calculations, PtNiO is found to be structurally
stable. The magnetic ground state is ferromagnetic with an effective magnetic
moment of 1.01 per unit cell. The electronic structure shows major
contributions from Pt-, Ni- and O- orbitals with band crossing
close to the Fermi level. The orbital contribution around 8 eV above the Fermi
level are from the Pt- orbitals forming a kagome like electronic structure
confirmed by surface Fermi surface spectral function. We found 20 pairs of
confirmed Weyl nodes along the magnetic easy axis [100]. These results are
expected to provide a useful and exciting platform for exploring and
understanding the magnetic Weyl physics in delafossites.Comment: 14 pages, 4 figure
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