Surface acoustic wave MEMS gyroscope

The design and performance evaluation of a surface acoustic wave (SAW) MEMS gyroscope is presented in this paper. This gyroscope is an integration of a SAW resonator and a SAW sensor. The SAW resonator is used to setup a stable reference vibration and SAW sensor is used for the detection of the secondary SAW generated by the Coriolis force. Further to this resonator, strategically positioned metallic dots that form an array along the standing wave anti-node locations are subjected to the reference vibratory motion. These vibrating dot arrays through the Coriolis effect will generate secondary SAW, which is picked up by the SAW sensor. The SAW resonator is designed and optimized using coupling-of-modes (COM) theory. In view of its one-layer planar configuration, this gyroscope can be implemented easily for applications requiring conformal mounting onto a surface of interest. This SAW gyroscope can be competitively priced inherently rugged, reliable and very sensitive. It is also capable of being wirelessly interrogated, without any sensor power source.     

Relations for the Fresnel reflection coefficients of a bimaterial interface independent of the angle of planewave incidence

A relation between the Fresnel reflection coefficients, for parallel and perpendicular planewave incidence, applicable to a dielectric-dielectric interface has been given by Azzam, the relationship being independent of the angle of incidence. Here, that relationship is generalized to include magnetic properties as well. Connection is also made with the Brewster angles relevant to the two polarizations.     

Dual Electrode Ensembles with Core and Shell Nanoelectrodes for Dopamine Sensing Applications

This paper presents the fabrication of dual electrode ensembles for electrochemical sensing of dopamine. A new dual electrode ensemble consists of vertically aligned core nanowire electrodes and a shell electrode with a hemi‐cylindrical nanocavity structure and submicron inter‐electrode spacing between the two working electrodes. By using a 3‐dimensional cavity structure of two working electrodes, collection efficiency in redox cycling of dopamine is enhanced. Initial measurement results show the ability to detect 200 μM concentration of dopamine with 69% collection efficiency on a dual electrode ensemble.     

Radiometric titration of diethanolamine with65ZnSO4 and determination of mono and diethanolamines in a mixture by a radiometric method

Radiometric titraction of diethanolamine with⁶⁵ZnSO₄ is reported. Determination of individual amounts of mono- and diethanolamines in a mixture is described.     

Influence of initial pH on the particle size and fluorescence properties of the nano scale Eu(III) doped yttria

Europium doped ytrrium oxide (Eu:Y₂O₃) was synthesized by a chemical wet method in the presence of tween-80 and ?-caprolactam in pH range 4-10. It has been observed that the variation in surface area, pore size, and pore volume of the final product, was strongly dependent on the initial pH of the solution. The powder with a large surface area (∼230 m²/g) and low pore diameter (∼16 nm) was obtained when the powder was processed at pH ∼4. The crystallite sizes of the powders processed at pH ∼4 and 10, were found to be 35 and 198 nm, respectively. The structural, chemical and thermal studies of the powders were characterized by X-ray diffraction (XRD), Fourier transformed infrared spectrophotometer (FTIR), Carbon analyzer and Thermogravimetry (TGA). High resolution transmission electron microscopic (HRTEM) study of heat treated powders showed a polygonal morphology with particle size of 40 nm when powder was derived at pH ∼4. Observations of fluorescence suggested that the ⁵D₀→⁷F₂ transition within europium was found to be highly dependent on the initial pH.     

Large amplitude flexural vibration of stiffened plates

The large amplitude free flexural vibration of thin, elastic orthotropic stiffened plates is studied. The boundary conditions considered are either simply supported on all edges or clamped on all edges and the in-plane edge conditions are either immovable or movable. The governing dynamic equations are derived in terms of non-dimensional parameters describing the stiffening achieved, and the solutions are obtained on the basis of an assumed one-term vibration mode shape for various stiffener combinations. In all cases, the non-linearity is found to be of the hardening type (i.e., the period of non-linear vibration decreases with increasing amplitude). Some interesting conclusions are drawn as to the effect of the stiffening parameters on the non-linear behaviour. A simple method of predicting the postbuckling and static large deflection behaviour from the results obtained in this analysis is included.     

Energy dependence of multiplicity in proton-nucleus collisions and models of multiparticle production

This is a continuation of our earlier investigation (Gurtuet al 1974Phys. Lett. 50 B 391) on multiparticle production in proton-nucleus collisions based on an exposure of emulsion stack to 200 GeV/c beam at the NAL. It is found that the ratioR _em = 〈n _s〉/〈n _ch〉, where 〈n _ch〉 is the charged particle multiplicity in pp-collisions, increases slowly from about 1 at 10 GeV/c to 1·6 at 68 GeV/c and attains a constant value of 1·71 ± 0·04 in the region 200 to 8000 GeV/c. Furthermore,R _em = 1·71 implies an effectiveA-dependence ofR _A =A ^0.18,i.e., a very weak dependence. Predictions ofR _em on various models are discussed and compared with the emulsion data. Data seem to favour models of hadron-nucleon collisions in which production of particles takes place through adouble step mechanism,e.g., diffractive excitation, hydrodynamical and energy flux cascade as opposed to models which envisage instantaneous production.     

Radial oscillations of neutron stars in strong magnetic fields

The eigen frequencies of radial pulsations of neutron stars are calculated in a strong magnetic field. At low densities we use the magnetic BPS equation of state (EOS) similar to that obtained by Lai and Shapiro while at high densities the EOS obtained from the relativistic nuclear mean field theory is taken and extended to include strong magnetic field. It is found that magnetized neutron stars support higher maximum mass whereas the effect of magnetic field on radial stability for observed neutron star masses is minimal.