Ultrasonic Concentration

Rhosonics Ultrasonic Concentration Analysers (www.rhosonics.nl) Pulse echo time of flight Concentration determination Yes Yes... 

Intrinsic to ionic surfactants and amphiphiles are solvophihc (or ionophilic) groups. We were therefore interested in learning whether the simple dialkylammonium bromides (2C,jN, n = 12, 14 Figure. d) that belong to the original family of synthetic bilayer membranes [10] form a bilayer in ionic liquids. Amphiphiles 2C N" were dispersed in three ionic hquids (Schemes 11.1-11.2) by ultrasonication (concentrations, 10 mM). While 2C12N+ as homogeneously dispersed in the conventional... 

Acoustic separation Acoustofluidics Acoustophoresis Ultrasonic concentration Ultrasonic particle manipulation Ultrasonic separation... 

Titanium IV) oxide, T1O2. See titanium dioxide. Dissolves in concentrated alkali hydroxides to give titanates. Mixed metal oxides, many of commercial importance, are formed by TiOj. CaTiOj is perovskite. BaTiOa, per-ovskite related structure, is piezoelectric and is used in transducers in ultrasonic apparatus and gramophone pickups and also as a polishing compound. Other mixed oxides have the il-menite structure (e.g. FeTiOj) and the spinel structure (e.g. MgjTiO ). 

Under ideal conditions (e.g., point sources producing spherical waves and no multiple reflections) a rectified backscattered signal represents line integrals of the ultrasonic reflectivity over concentric arcs centered at the transducer position. To reconstruct the reflection tomo-... 

Figure I represents a two-dimensional damage distribution of an impact in a 0/90° CFRP laminate of 3 mm thickness. Unlike in ultrasonic testing, which is usually the standard method for this problem, there is no shadowing effect on the successive layers by delamination echos. With the method of X-ray refraction the exact concentration of debonded fibers can be calculated for each position averaged over the wall thickness. Additionally the refraction allows the selection of the fiber orientation. The presented X-ray refraction topograph detects selectively debonded fibers of the 90° direction.

Assessment variations ranging from 2 to 3 dB are normal, even with well-trained ultrasonic inspectors. With longer work assignments or adverse external influences (cold, heat, dust, noises, etc.) considerably higher variations (12 dB and more) are often observed due to lack of concentration and to tiredness [1]. 

We are confident that any user of this combined evaluation technique, as well as the development of future test standards for manual ultrasonic testing will benefit from this result, because it allows a greater flexibility in the applicable method without loosing reliability. Often an expensive production of a reference block can be avoided and therefore testing costs are reduced. Since all calculations are performed by a PC, the operator can fully concentrate on his most important duty scanning the workpiece and observing the A-scan. Additional time will be saved for the test documentation, since all testing results are stored in the instrument s memory (the PC s hard drive) with full link to the Software World (Microsoft Word, Excel, etc.). 

Another advantage with the system is that the quality of the scanning, in terms of the angle towards the weld and track partition is increased compared to manual ultrasonic testing due to the fact that the scanning technician is able to concentrate on the object rather than on the oscilloscope while scanning. 

The choice of the solvent also has a profound influence on the observed sonochemistry. The effect of vapor pressure has already been mentioned. Other Hquid properties, such as surface tension and viscosity, wiU alter the threshold of cavitation, but this is generaUy a minor concern. The chemical reactivity of the solvent is often much more important. No solvent is inert under the high temperature conditions of cavitation (50). One may minimize this problem, however, by using robust solvents that have low vapor pressures so as to minimize their concentration in the vapor phase of the cavitation event. Alternatively, one may wish to take advantage of such secondary reactions, for example, by using halocarbons for sonochemical halogenations. With ultrasonic irradiations in water, the observed aqueous sonochemistry is dominated by secondary reactions of OH- and H- formed from the sonolysis of water vapor in the cavitation zone (51—53). 

Doppler Flow Meters. Doppler flow meters sense the shift in apparent frequency of an ultrasonic beam as it is reflected from air bubbles or other acoustically reflective particles that ate moving in a Hquid flow. It is essential for operation that at least some particles ate present, but the concentration can be low and the particles as small as ca 40 p.m. CaUbration tends to be influenced by particle concentration because higher concentrations result in mote reflections taking place neat the wall, in the low velocity portion of the flow profile. One method used to minimize this effect is to have separate transmitting and receiving transducers focused to receive reflections from an intercept zone neat the center of the pipe. 

Ultrasonic Welding. Ultrasonic welding has been appHed to Tefzel with weld strength up to 80% of the strength of the base resin. Typical conditions include a contact pressure of 172 kPa (25 psi) and 1—2 s cycle time. The two basic designs, the shear and butt joints, employ a small initial contact area to concentrate and direct the high frequency vibrational energy. 

The transducers are typically mounted on an outside wall of the cleaning tank, but may also be mounted on the inside of the tank below the solution level in a sealed container. Alkaline cleaning solutions are typically at the same concentration and temperature as for a normal immersion cleaner, but the time required to clean may be less because of the ultrasonic effect. Like electrocleaning, ultrasonic cleaning produces an extremely clean surface. The main drawback is the relatively high cost. 

Ultrasonic spectroscopy technology, developed in the early 1990s, is proving useful in the lubricant and food industries for measurement of od-in-water emulsions at process concentrations. This technology is anticipated to find a wide range of industrial appHcations. 

Figure 4-2. The phase lag between concentration and pressure in ultrasonic absorption. The cyclic pressure changes are produced by the sound wave. The cyclic concentration changes are a response to the pressure changes.

This value agrees well with the rest found in [191] but not with point (4), which was shown to be ZR = 3.1 in ultrasonic experiment [216], No such discrepancy was found for pure nitrogen. Therefore it may be attributed to the low sensitivity of ultrasonic absorption measurements when nitrogen is present at small concentration in a gas mixture. 

Sample solution A 3 g sample of woodruff was added to 30 ml warm methanol and placed in the ultrasonic bath for 10 min. After filtration the solution was concentrated to ca. 20% of the initial volume under reduced pressure. A portion of the solution was centrifuged at 1200 rpm for 2 min and the clear supernatant was applied to the layer as a band. 

The ductility of GRT-polyethylene blends drastically decreases at ground rubber concentration in excess of 5%. The inclusion of hnely ground nitrile rubber from waste printing rollers into polyvinyl chloride (PVC) caused an increase in the impact properties of the thermoplastic matrix [76]. Addition of rubber powder that is physically modihed by ultrasonic treatment leads to PP-waste ethylene-propylene-diene monomer (EPDM) powder blends with improved morphology and mechanical properties [77]. 

As a starting material, TTBP (Titinium tetraisoproxide, Aldrich Chem. Co. ltd., 98%) was dissolved in distilled water by adding nitric acid. Total titanium ion concentration was fixed at 0.5M. The precursor solution was converted into droplets by ultrasonic nebulizer of 1.7MHz. These droplets were transported to the reaction region by carrier gas. 

Here p is the solution density, v the sound velocity, ctp the coefficient of thermal expansion, Cp the specific heat, and F the concentration dependence of the equilibrium, r = [LS] -f- [HS] . The measurement of ultrasonic relaxation thus enables the determination of both the relaxation time x and the... 

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