We have proposed and demonstrated experimentally a novel and simple pressure sensor based on mechanically induced long period optical fiber gratings. We report here for the first time to our knowledge the characterization of mechanically induced long period fiber gratings in novel multimode-singlemode-multimode fiber structure. The MLPFG induced in single mode fiber and multimode fibers are studied separately and the results are compared with MLPFG induced in MSM fiber structure. MLPFG in MSM structure has much greater sensitivity. We have obtained maximum transmission loss peak of around 18 dB, and the sensitivity of pressure sensor is 8 dB/Kg.
Thin films of amorphous diamond like carbon (a:DLC) were deposited by
using a novel technique. By electrodeposition from methanol-camphor solution
thin a:DLC films were deposited on non-conductive glass substrates and also on
high resistive Si substrates, by using a fine wire mesh electrode, at atmospheric
pressure and temperature below 350 K. Thin films of a:DLC were doped by
incorporation of nitrogen (a:N-DLC) and boron (a:B-DLC) using urea and boric
acid with methanol-camphor solution respectively during the electrodeposition
process. From transmittance measurements in the UV-VIS-NIR region, the optical
energy band gap of about 1.0 eV for undoped a:DLC film, 2.12 eV for a:N-DLC and
2.0 eV for a:B-DLC films were determined. The spectra showed high transparency
in the visible and NIR region. Fourier transform infrared spectroscopy (FTIR)
measurements showed the appearance of various C-H and C-C
bonding in the spectrum of undoped amorphous DLC film and confirmed C-N and C=N
bond formation in a:N-DLC film. From the temperature variation of d.c.
conductivity studies, the activation energies were determined and found to be
0.75 eV, 0.32 eV and 0.58 eV for undoped a:DLC films, a:N-DLC and a:B-DLC films
respectively. Electrical resistivity at room temperature was reduced by the
doping effect, from 109 Ω-cm for undoped films to 107 Ω-cm
for nitrogen doped films and 108 Ω-cm for boron doped films.
The aim of the present paper is to obtain the two-dimensional deformation of a two-phase elastic medium consisting of half-spaces of different ri- gidities in welded contact due to a buried long strike-slip fault. The solution is valid for arbitrary values of the fault-depth and the dip angle. The effect of fault-depth on the displacement and stress fields for different values of dip angle has been studied numerically. It is found that the displacement field varies significantly for a buried fault from the corresponding displacement field for an interface-breaking fault. The contour maps showing the stress field for various dip angles for buried and interface-breaking fault have been plotted. It has been observed that the stress field varies significantly for a buried fault from the corresponding stress field for an interface-breaking fault.
An exact scalar field cosmological model is constructed from the
exact solution of the field equations. The solutions are exact and no
approximation like slow roll is used. The model gives inflation, solves horizon
and flatness problems. The model also gives a satisfactory estimate of present
vacuum energy density as well as vacuum energy density at Planck epoch and
solves cosmological constant problem of 120 orders of magnitude discrepancy of
vacuum energy density. Further, this model predicts existence of dark
matter/energy and gives an extremely accurate estimate of present energy
density of dark matter and energy. Along with explanations of graceful exit, radiation
era, matter domination, this model also indicates the reason for present
accelerated state of the universe. In this work a method is shown following
which one can construct an infinite number of exact scalar field inflationary