Laser vibrometry from a moving ground vehicle

We investigated the fundamental limits to the performance of a laser vibrometer that is mounted on a moving ground vehicle. The noise floor of a moving laser vibrometer consists of speckle noise, shot noise, and platform vibrations. We showed that speckle noise can be reduced by increasing the laser spot size and that the noise floor is dominated by shot noise at high frequencies (typically greater than a few kilohertz for our system). We built a five-channel, vehicle-mounted, 1.55 μm wavelength laser vibrometer to measure its noise floor at 10 m horizontal range while driving on dirt roads. The measured noise floor agreed with our theoretical estimates. We showed that, by subtracting the response of an accelerometer and an optical reference channel, we could reduce the excess noise (in units of micrometers per second per Hz(1/2)) from vehicle vibrations by a factor of up to 33, to obtain nearly speckle-and-shot-noise-limited performance from 0.3 to 47 kHz.     

Future of petrochemical raw materials in oleochemical markets

The petrochemical industry (PCI) has undergone profound changes during the last decade and is continuing to adjust to changing world economic conditions. One of the most important of these is the price of crude oil. Although an equilibrated pricing structure remains to be demonstrated, anticipated adequacy of supply and versatile, innovative methods of converting crude and natural gas to high valued products assures it a vital and healthy future. The product areas in which the PCI and the oleochemical industry (OCI) overlap are actually quite small in terms of the total capacity. In those limited areas of overlap, we expect the role of the PCI during the next several years to continue to be cone of a complementary nature. By providing security of supply at competitive prices, it will create confidence and reliability which will benefit both the petrochemical and oleochemical industries. And most significantly, the resources of the petrochemical industry will also allow it to respond to new market conditions, particularly those of accelerated volume needs and specific performance, with the flexibility and creativity which have been its hallmarks.     

Measurement of radial expansion and tumbling motion of a high-speed rotor using an optical sensor system

In order to investigate the load capacity and the strength properties of high-speed rotors, dynamic deformation and vibration measurements are of importance, in particular at lightweight composite devices which cannot be simulated reliably. This is a challenging task in metrology since non-contact inspection techniques are required which offer micron uncertainties and high temporal resolution simultaneously, also under vacuum conditions. In order to meet these requirements, a non-incremental laser Doppler distance sensor system was developed using fiber and diffractive optics. In this paper we present for the first time high-speed deformation measurements of a cylindrical steel rotor using this novel sensor system. The radial rotor expansion of only some microns was determined despite the presence of an unsteady tumbling motion of the rotor, which was measured simultaneously. Future prospects are discussed including the possibility to measure non-metallic devices such as fiber-reinforced composites.