Ultrasonic measurement systems

In each case, the volumetric rate of flow can be determined by measuring the liquid levels in the appropriate place. This is often achieved using an ultrasonic measuring system (Fig. 6.7d) in which the time taken for an ultrasonic wave to be reflected from the liquid surface is measured (see also Section 6.5.5). Accuracies of 2.5 mm/m distance between sensor and liquid surface are not uncommon. Standard designs of open channel restrictions can be found in BS 3680(l4). 

The key elements of an ultrasonic measurement system are a transducer, which converts an electrical impulse into mechanical vibration, a signal generator to produce the original electrical excitation signal, and a display... 

An ultrasonic measuring system was developed to measure the attenuation coefficient/loss factor of car-tyre rubber samples as a function of the temperature between about -40°C and 150°C. These measurements were performed on sample disks of vulcanised rubber having a diameter of 60 mm. and a thickness of 13 mm. 

For ultrasonic imaging systems (B-, C- and C-scans) single-shot measurements, fast data recordings, and fast data transfer must be performed. 

The transfer efficiencies for ultrasonic nebulizers (USN) are about 20% at a sample uptake of about 1 ml/min. Almost 100% transfer efficiency can be attained at lower sample uptakes of about 5-20 pl/min. With ultrasonic nebulizers, carrier gas flows to the plasma flame can be lower than for pneumatic nebulizers because they transfer sample at a much higher rate. Furthermore, reduction in the carrier-gas flow means that the sample remains in the mass measurement system for a longer period of time which provides much better detection limits. 

Corrosion may be monitored by measuring changes in thickness with time using ultrasonic thickness gages. An automated ultrasonic inspection system has been devised and used in monitoring corrosion in nuclear waste containers and typical variations in ultrasonic indications in corroded and uncorroded areas have been recorded successfully. Major types of equipment inspection by ultrasonic technique has been done in mill components, power equipment, jet engine parts, aircraft components, railway materials, automotive components and other machinery components. 

In non-scattering systems, ultrasonic properties and the volume fraction of the disperse phase are related in a simple manner. In practice, many emulsions and suspensions behave like non-scattering systems under certain conditions (e.g. when thermal and visco-inertial scattering are not significant). In these systems, it is simple to use ultrasonic measurements to determine 0 once the ultrasonic properties of the component phases are known. Alternatively, if the ultrasonic properties of the continuous phase, 0and p2 are known, the adiabatic compressibility of the dispersed phase can be determined by measuring the ultrasonic velocity. This is particularly useful for materials where it is difficult to measure jc directly in the bulk form (e.g. powders, granular materials, blood cells). 

Aeration in a slurry cause large ultrasonic attenuations making accurate particle size measurement impossible. Aerated slurry can be fed to a holding tank and ultrasonic measurements made once the aeration level has dropped low enough to allow meaningful measurements. Clearance times were found to be short enough for a baffled tank passive de-aeration system to be feasible. 

In terms of equipment. McDonnell Douglas proposes an automated ultrasonic scanning system (AUSS) with 9 axes of motion, a 7 axes ultrasound system (ADIS-II) and a portable inspection system (MAUS II) for aerospace composite structure inspection [36], The ultrasonic resin analyser (URA 2002A from Quatro Technologies) can be used to measure the resin content in polymer based composites [10]. The UCMS-200 ultrasonic cure monitoring system from Micromet Instruments utilizes measurements of the ultrasonic sound speed to monitor changes in the viscosity, rigidity of composites. 

Ultrasonic measurement techniques applicable to food emulsions are reviewed extensively elsewhere (11—15) and only a brief introduction is presented here. Most ultrasonic measirrement systems require an electrical signal generator that is used to excite an ultrasonic transducer to produce an acoustic wave which, after passing through the emulsion, is detected by a second transducer (or the first after a reflection). Finally, a display system, usually a computer or oscilloscope, is used to record and store the elec-... 

Many plants decided to install water level monitoring systems in response to this problem. A typical choice is the ultrasonic level measurement system. Some HI are focused on providing interlocks to automatically terminate the draining upon a low level signal. Other HI concern detection of vortex phenomena and automatic makeup of the reactor coolant system. 

In this article, we introduce a recently developed ultrasonic spectroscopy method and review its application to polymeric studies. First, the principle of this ultrasonic spectroscopy is explained including the instruments and data analysis methods. Then, actual application of this measuring system is described for the characterization of solid polymers and the observation of phase transition phenomenon in liquid crystals and ferroelectric (VDF/TrFE) copolymer. Finally, the extension of this system to two-dimensional measuring and the application to non-destructive testing of CFRP (carbon fiber reinforced plastics) are discussed. 

Today s ultrasound technology has a wide range of applications in industrial and medical field, from distance measurement to medical diagnostic imaging. The fields such as dermatology, ophthalmology, and cardiovascular medicine require ultrasonic imaging systems. CMUTs enable... 

Quite a different appUcation of ultrasonic measurements to amorphous alloys was made by Doussineau et al. (1978). These authors measured the temperature dependence of the ultrasonic attenuation and described their experimental results in terms of a resonant interaction with two-level systems such as were described in section 8. 

The paper reports a noninvasive technique to measure the mechanical properties of the bulk soft tissues by a pulsed ultrasonic Doppler system. An ultrasonic transducer was used to measure internal displacement resulting from external acoustical perturbations. Measurements were made at four sites of 8 aboveknee residual limbs. The Young s moduli were found in a range of 53-141 kPa. Superficial tissue had a significantly higher modulus than the tissue beneath. 

Ultrasonic measurements have also proven useful in the characterization of polymer melts (see Section 4.3.3.1). The ultrasonic transit time ( Laufzeit ) is dependent on the elastic properties of the material, pressure, temperature, chemical composition, and structure. It has been found [37] that the ultrasonic transit time is a sensitive measure of the condition of the polymer melt, in particular melt homogeneity. In a process control system, the ultrasonic transit time can provide a more useful feedback control signal than a single melt temperature measurement. 

ANS Of course, we have been measuring profiles directly with our pulsed ultrasonic Doppler system and we see a number of non-parabolic type features. But in this calculation, the assumption of Newtonian flow is needed only to calculate an average value for the friction factor. That s the only question pertinent to the model at this point. 

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