Ultrasound drying

Rossello, C., Mulet, A., 2012a. Intensification of low temperature drying by using ultrasound. Drying Technol. 30(11-12) 1199-1208. 

S,5S,5 S)-5-(2-Alkfiiylmninoy or (4S,5S,5 S)-5-(2-Alkynylamino)-2,2-dimethy 1-4-phenyl-1,3-dioxane 9 3.91 g (10.5 mmol) of CeCI, 7H,(> is dried in vacuo at 140T70.5 lorr for 2 h. The following operations arc performed under argon protection. After cooling to r.t. 50 mL of anhyd THF is added and the resulting colorless slurry is stirred for 2 h under assistance of ultrasound. Subsequently, the suspension is cooled to... 

In a related reaction, aromatic carboxylic acids were condensed to a-diketones (2 ArCOOH —> ArCOCOAr) on treatment with excess Li in dry THF in the presence of ultrasound. ... 

A 2-week diary of wet and dry nights prior to intervention is useful in that it can be used to monitor the response to treatment. A first-morning urine specific gravity may help to predict response to desmopressin therapy. Polysymptomatic presentation may require a more elaborate work-up, including voiding cystourethrogram, renal and/or bladder ultrasound, urodynamics, and sleep studies. 

The gas-driven transducers are simply whistles with high frequency output. Dog whistles and sirens can be given as the two examples of gas-driven transducers. These transducers can be used to break down foams and agglomerates of dust and for the acceleration of drying processes. However, these types do not have any significant chemical applications, as it is not possible to achieve a sufficiently high-pressure intensity in airborne ultrasound by this method. 

Gold sulphide had a featureless non-crystalline plain surface with very sharp and smooth edges of the dried mass. However, the smoothness of the surface was destroyed completely with blisters appearing as a result of cavitation, after 30 min of ultrasound irradiation. A closer look at the surface at x 7,500 magnification reveals extensive surface erosion as a result of the micro-jets streaming. 

Liposphere formulations are prepared by solvent or melt processes. In the melt method, the active agent is dissolved or dispersed in the melted solid carrier (i.e., tristearin or polycaprolactone) and a hot buffer solution is added at once, along with the phospholipid powder. The hot mixture is homogenized for about 2 to 5 min, using a homogenizer or ultrasound probe, after which a uniform emulsion is obtained. The milky formulation is then rapidly cooled down to about 20°C by immersing the formulation flask in a dry ice-acetone bath, while homogenization is continued to yield a uniform dispersion of lipospheres. 

FIG. 5 Effects of varying raw material treatments during osmotic dehydration on moisture (MC) and solid (SC) content expressed on initial dry matter (idm). Apple cubes, ultrasound (U) (Simal et al., 1998) apple slices, vacuum (V) (Salvatori et al., 1998b) and bell pepper disks, high temperature (Ade-Omowaye et al., 2002b). 

M. C. Yebra and S. Cancela, Continuous ultrasound-assisted extraction of cadmium from legumes and dried fruit samples coupled with on-line preconcentration-flame atomic absorption spectrometry, Anal. Bioanal. Chem., 382(4), 2005, 1093-1098. 

The ultrasound-assisted extraction of freeze-dried plant-based materials normally takes 2 hr. If the extract is evaporated to dryness, a total of 3 hr is necessary. As an additional sample preparation step, 2 to 4 days should be allotted for freeze-drying fresh plant materials, depending on the quantity of the material. Homogenizer-assisted extraction of fresh fruit takes <4 hr. 

Solids usually have larger ultrasonic velocities and acoustic impedance, than liquids, which have larger values than gasses. Air has a very low acoustic impedance compared to liquids or solids which means that it is difficult to transmit ultrasound from air into a condensed material. This can be a problem when ultrasound is used to test dry materials, e.g., biscuits or egg shells. A small gap of air between an ultrasonic transducer and the sample to be tested can prevent ultrasound from being transmitted into the material. For this reason coupling materials (often aqueous or oil based) can be placed between the transducer and sample to eliminate the effects of the air gap, or alternatively soft-tip ultrasonic transducers can be used. 

The barbituric acid derivative 2 (0.50 mmol) was ground in an agate mortar. Solid diazonium salt 1 (0.50 mmol) was added and co-ground in 5 portions for 5 min, each. Most of the diazonium band at 2280 cm-1 had disappeared, but completion of the reaction was achieved by 24 h ultrasound application in a test tube. After neutralization (0.5 n NaOH, 20 mL), washings (H20) and drying, the quantitatively obtained products 3a-e assume the hydrazono structure. 

Chapter 4), and many more. The last imperative covers technologies that use centrifugal fields for contacting (Chapters 2 and 3), separations, and crystallization or that involve extremes of pressure and temperature, ultrasound waves, microwaves (for e.g., drying) and electric fields (for e.g., separation or dispersion). 

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