Microwave spectroscopy is a very accurate method to determine the potential barrier restricting the rotation of a methyl group [1 —3] . The finite barrier hindering internal rotation normally splits each rotational line into two components. This splitting depends strongly on the height of the barrier. Generally the barrier is determined from the splittings in the ground torsional state. But for...

A parameter study is presented to determine effects of planet gear design parameters on the global modal behaviour planetary geared rotor systems. The sensitivity analysis conducted using a three-dimensional dynamic model system for number gears, mistuning, mass mesh stiffness and speed. These have varying impacts both natural frequencies mode shapes, therefore vibration modes determined by com...

Low-frequency torsional vibration modes of the conjugated polyene chain of the biologically important chromophore retinal are of major relevance when studying its photoisomerization dynamics. We present absorptivity and dispersion spectra of three di€erent retinal isomers in the far-infrared region between 10 and 100 cmÿ1 (0.3±3.0 THz) measured by terahertz time-domain spectroscopy at 298 and 1...

The primary goal of the this project was to demonstrate the feasibility of detecting changes in shaft natural frequencies (such as those associated with a shaft crack) on rotating machinery in electric power generation plants using non-contact, nonintrusive measurement methods. During the operation of power plant equipment, torsional natural frequencies are excited by turbulence, friction, and ...

In this work we present a methodology for the accurate numerical computation of the rovibrational G matrix in any molecule. A C++ program is developed to apply this methodology. Using polymorphism, the program can handle the output of any of the available electronic structure codes. The objective is to compute the kinetic contribution to the rovibrational Hamiltonian from the results of molecul...

The problem of coupled flexural-torsional nonlinear vibrations of a piezoelectrically-actuated microcantilever beam as a typical configuration utilized in microcantilever-based sensing is being investigated. The actuation and sensing are both facilitated through bonding a piezoelectric layer (here, ZnO) on the microcantilever surface. Considering different geometrical configurations for the bea...

Based on the model of Higgins and Goodman, we describe a dynamically generated fuzzy neural network (DGFNN) approach to control, from input–output data, using on-line learning. The DGFNN is complete with the following powerful features drawn or modified from the existing literature: (1) a small FNN is created from scratch—there is no need to specify initial network architecture, initial members...

Rotor dynamics plays an important role in many engineering fields such as gas turbine, steam turbine, reciprocating and centrifugal compressors, the spindle of machine tools, and so on. Owing to the growing demands for high power, high speed, and light weight of the rotor-bearing system, computations of critical speeds and steady-state response at synchronous and sub critical resonances become ...