Water

Povey, Malcolm J. W.

doi:10.1016/b978-012563730-5/50003-9

Cited by 5 publications

(11 citation statements)

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“…in the high-concentration tail of E3. These diversions may have been caused by the high molecular heterogeneity of the asphaltenes 51 , micro air bubbles 52 or trace impurities. This is illustrated numerically in our synthetic data study where we emulate one of our specimens and a specimen from Andreatta et al 39 to validate our MCMC scheme.…”

Section: Methodsmentioning

confidence: 99%

“…For multi-phase fluids which are well-dispersed, and ignoring the effects of sound scattering (valid for sufficiently low concentration of scatterers and away from scattering resonances) 52 , Equation ( 3 ) can be applied with density and compressibility represented by weighted averages of the mixture components. An extension of Equation ( 3 ) allows to detect the onset of surfactant aggregation into micelles to detect the critical micelle concentration, as proposed by Zielinski et al 49 , where the full model derivation is given.…”

Section: Methodsmentioning

confidence: 99%

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Estimating the asphaltene critical nanoaggregation concentration region using ultrasonic measurements and Bayesian inference

Svalova

Walshaw

Lee

et al. 2021

Sci Rep

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Bayesian inference and ultrasonic velocity have been used to estimate the self-association concentration of the asphaltenes in toluene using a changepoint regression model. The estimated values agree with the literature information and indicate that a lower abundance of the longer side-chains can cause an earlier onset of asphaltene self-association. Asphaltenes constitute the heaviest and most complicated fraction of crude petroleum and include a surface-active sub-fraction. When present above a critical concentration in pure solvent, asphaltene “monomers” self-associate and form nanoaggregates. Asphaltene nanoaggregates are thought to play a significant role during the remediation of petroleum spills and seeps. When mixed with water, petroleum becomes expensive to remove from the water column by conventional methods. The main reason of this difficulty is the presence of highly surface-active asphaltenes in petroleum. The nanoaggregates are thought to surround the water droplets, making the water-in-oil emulsions extremely stable. Due to their molecular complexity, modelling the self-association of the asphaltenes can be a very computationally-intensive task and has mostly been approached by molecular dynamic simulations. Our approach allows the use of literature and experimental data to estimate the nanoaggregation and its credible intervals. It has a low computational cost and can also be used for other analytical/experimental methods probing a changepoint in the molecular association behaviour.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Estimating the asphaltene critical nanoaggregation concentration region using ultrasonic measurements and Bayesian inference

Svalova

Walshaw

Lee

et al. 2021

Sci Rep

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“…Low intensity ultrasonic techniques are being increasingly applied to determine a number of technologically useful properties of food materials – . One set of properties that has a direct bearing on product stability and acceptability is the food’s mechanical (or rheological) properties , .…”

Section: Introductionmentioning

confidence: 99%

“…A technique typically used to ascertain the ultrasonic velocity in a food material is to measure the propagation of a short ultrasonic pulse through the food specimen , . This pulse is constituted from the superposition of acoustic excitations spanning a continuous range of frequencies, with a width in frequency that is inversely proportional to the pulse length in time.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Ultrasonic Velocities in Dispersive and Nondispersive Food Materials

Cobus

Ross

Scanlon

et al. 2007

J. Agric. Food Chem.

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Ultrasonic techniques are increasingly being used to evaluate the properties of food materials. Interpretation of the structure and dynamics on the basis of measured ultrasonic parameters requires rigorous definition of ultrasonic parameters such as velocity, especially since many food materials can display considerable dispersive behavior (changes in velocity with frequency). Agar gel (2% w/v) and agar gel (2% w/v) with a regular array of bubbles (8% volume fraction) were chosen as nondispersive and dispersive materials, respectively. Frequency and time domain techniques were used to analyze velocities. Signal, phase, and group velocities were identical in the agar gel and were indistinguishable from those of water (1500 m s(-1)), indicating the predominant effect of the bulk modulus of the water they contain on the longitudinal modulus of the gel. In contrast, the inclusion of the bubbles in the agar gel led to strongly dispersive behavior, with group velocities varying by 1000 m s(-1) above and below the 1500 m s(-1) of the agar gel without bubbles, depending on frequency. The addition of bubbles also led to strong attenuation in the agar gel with a peak occurring at a frequency associated with a band gap arising from destructive interference of sound waves. The results show that care must be taken when comparing ultrasonic parameters derived from experiments on food materials performed at different frequencies or with different ultrasonic techniques.

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“…Where a> is the radial frequency, k is the complex wave vector, p is the density of the material and u is the velocity of sound in this material Povey, 1997;Williams, 1983). We will talk more about acoustic impedance in the ultrasonic equipment section.…”

Section: Sound Propertiesmentioning

confidence: 99%

Effects of power ultrasound treatments on properties of Longissimus beef muscle

Gonzalez

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This study was conducted to determine the effects of low intensity power ultrasound on properties of beef muscles. Ten pairs of loins from steer carcasses, USDA Choice, maturity A were obtained 24 hrs after slaughter for this study. Each loin was divided into at least 12 steaks and each steak was divided into 4 pieces, labeled, vacuum packed individually, and divided into groups: Day 1 and Day 7. Four treatments: control (no treatment), 1.5 W/cm 2 , 3 W/cm 2 , and 5 W/cm 2 electrical intensity power levels were applied (at 20 kHz) for 1.5 minutes/side (3 minutes total time) under refrigerated conditions. Ultrasound treatments were applied using a direct probe commercial ultrasonic system. Cooking yields, shear force (Warner-Bratzler), and ultrasonic power entering the samples were measured. In addition, microscopy and SDS PAGE tests were conducted on the samples. No difference in shear force was observed for day 1, however at day seven the 5 W/cm 2 treatment required a lower force (P<0.05) to shear the sample. Histological cross-sectional samples for all treatments showed separation of the muscle bundles when compared with the control. SDS PAGE did not showed any difference between treatments.

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Water

Cited by 5 publications

References 0 publications

Estimating the asphaltene critical nanoaggregation concentration region using ultrasonic measurements and Bayesian inference

Estimating the asphaltene critical nanoaggregation concentration region using ultrasonic measurements and Bayesian inference

Comparison of Ultrasonic Velocities in Dispersive and Nondispersive Food Materials

Effects of power ultrasound treatments on properties of Longissimus beef muscle

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