scholarly journals A study of the effect of PEG-40 surfactant concentration on the stability of microbubbles post-injection through various needle sizes and its ultrasound imaging performance

2019 ◽  
Author(s):  
Dhiman Das ◽  
Kathleen K. A. Villanueva ◽  
Manojit Pramanik
Keyword(s):  
Ultrasound Imaging ◽  
Surfactant Concentration ◽  
Post Injection ◽  
The Stability ◽  
Imaging Performance

Effect of the Surfactant Concentration on Sinking Electric Discharge Machining Performance with Water-in-Oil Emulsion as Dielectric

2011 ◽  
Vol 189-193 ◽  
pp. 3153-3157
Author(s):  
Yan Zhen Zhang ◽  
Yong Hong Liu ◽  
Ren Jie Ji ◽  
Bao Ping Cai
Keyword(s):  
Physical Properties ◽  
Electric Discharge ◽  
Surfactant Concentration ◽  
Emulsion Stability ◽  
Experimental Results ◽  
Machining Performance ◽  
Electric Discharge Machining ◽  
Oil Emulsion ◽  
The Stability ◽  
Water In Oil Emulsion

In this paper, the EDM performance of water-in-oil (W/O) emulsions dielectric with different surfactant concentration is investigated by correlated to its physical properties, such as viscosity and droplets size, which is predominantly determined by the surfactant concentration. Experimental results show that the stability of the W/O emulsions increases with increasing surfactant concentration, whereas the EDM performance deteriorates with increasing surfactant concentration. So, taking a comprehensively consideration of the emulsion stability and EDM performance, the concentration of surfactant must be appropriately selected.

Surfactant Effects on Fluid-Elastic Instabilities of Liquid-Lined Flexible Tubes: A Model of Airway Closure

1993 ◽  
Vol 115 (3) ◽  
pp. 271-277 ◽  
Author(s):  
D. Halpern ◽  
J. B. Grotberg
Keyword(s):  
Film Thickness ◽  
Surfactant Concentration ◽  
Evolution Equations ◽  
Liquid Films ◽  
Nonlinear Evolution Equations ◽  
Small Airways ◽  
Airway Closure ◽  
Elastic Tubes ◽  
Critical Film Thickness ◽  
The Stability

A theoretical analysis is presented predicting the closure of small airways in the region of the terminal and respiratory bronchioles. The airways are modelled as thin elastic tubes, coated on the inside with a thin viscous liquid lining. This model produces closure by a coupled capillary-elastic instability leading to liquid bridge formation, wall collapse or a combination of both. Nonlinear evolution equations for the film thickness, wall position and surfactant concentration are derived using an extended version of lubrication theory for thin liquid films. The positions of the air-liquid and wall-liquid interfaces and the surfactant concentration are perturbed about uniform states and the stability of these perturbations is examined by solving the governing equations numerically. Solutions show that there is a critical film thickness, dependent on fluid, wall and surfactant properties above which liquid bridges form. The critical film thickness, εc, decreases with increasing mean surface-tension or wall compliance. Surfactant increases εc by as much as 60 percent for physiological conditions, consistent with physiological observations. Airway closure occurs more rapidly with increasing film thickness and wall flexibility. The closure time for a surfactant rich interface can be approximately five times greater than an interface free of surfactant.

A Comparison Between Urethane and Gel Test Objects for Ultrasound Imaging Performance Testing

Ultrasound ◽  
2007 ◽  
Vol 15 (2) ◽  
pp. 105-108 ◽  
Author(s):  
Hannah L. Green ◽  
Nicholas J. Dudley ◽  
Nicholas M. Gibson
Keyword(s):  
Ultrasound Imaging ◽  
Performance Testing ◽  
Imaging Performance ◽  
Test Objects

scholarly journals Contrast-enhanced sonography with biomimetic lung surfactant nanodrops

2020 ◽  
Author(s):  
Alec N. Thomas ◽  
Kang-Ho Song ◽  
Awaneesh Upadhyay ◽  
Virginie Papadopoulou ◽  
David Ramirez ◽  
...  
Keyword(s):  
Ultrasound Imaging ◽  
Lung Surfactant ◽  
Liquid Core ◽  
Acoustic Droplet Vaporization ◽  
Droplet Vaporization ◽  
Contrast Enhanced ◽  
Biomimetic Approach ◽  
The Stability

AbstractNanodrops comprising a perfluorocarbon liquid core can be acoustically vaporized into echogenic microbubbles for ultrasound imaging. Packaging the microbubble in its condensed liquid state provides distinct advantages, including in situ activation of the acoustic signal, longer circulation persistence, and the advent of expanded diagnostic and therapeutic applications in pathologies which exhibit compromised vasculature. One obstacle to clinical translation is the inability of the limited surfactant present on the nanodrop to encapsulate the greatly expanded microbubble interface, resulting in ephemeral microbubbles with limited utility. In this study, we examine a biomimetic approach to stabilizing an expanding gas surface by employing the lung surfactant replacement, Beractant. Lung surfactant contains a suite of lipids and surfactant proteins that provides efficient shuttling of material from bilayer folds to the monolayer surface. We therefore hypothesized that Beractant would improve stability of acoustically vaporized microbubbles. To test this hypothesis, we characterized Beractant surface dilation mechanics and revealed a novel biophysical phenomenon of rapid interfacial melting, spreading and re-solidification. We then harnessed this unique spreading capability to increase the stability and echogenicity of microbubbles produced after acoustic droplet vaporization for in vivo ultrasound imaging. Such biomimetic lung surfactant-stabilized nanodrops may be useful for applications in ultrasound imaging and therapy.Graphical Abstract

scholarly journals The Imaging Performance of Diagnostic Ultrasound Scanners Using the Edinburgh Pipe Phantom to Measure the Resolution Integral – 15 Years of Experience

2020 ◽  
Author(s):  
Carmel M. Moran ◽  
Scott Inglis ◽  
Karne McBride ◽  
Christopher Mcleod ◽  
Stephen D. Pye
Keyword(s):  
Clinical Practice ◽  
Ultrasound Imaging ◽  
Figure Of Merit ◽  
Integral Characteristic ◽  
Depth Of Field ◽  
Single Element ◽  
Effective Metric ◽  
Two Parameters ◽  
Imaging Performance ◽  
Single Figure

AbstractThe grayscale imaging performance of a total of 368 different scanner/transducer combinations from 39 scanner manufacturers measured over a period of 15 years is presented. Performance was measured using the resolution integral, a single figure-of-merit to quantify ultrasound imaging performance. The resolution integral was measured using the Edinburgh Pipe Phantom. Transducers included single element, linear, phased, curvilinear and multi-row arrays. Our results demonstrate that the resolution integral clearly differentiates between transducers with varying levels of performance. Two further parameters were also derived from the resolution integral: characteristic resolution and depth of field. We demonstrate that these two parameters can successfully characterize individual transducer performance and differentiate between transducers designed for different clinical and preclinical applications. In conclusion, the resolution integral is an effective metric to quantify and monitor grayscale imaging performance in clinical practice.

scholarly journals Impact of Aperture, Depth, and Acoustic Clutter on the Performance of Coherent Multi-Transducer Ultrasound Imaging

2020 ◽  
Vol 10 (21) ◽  
pp. 7655
Author(s):  
Laura Peralta ◽  
Alessandro Ramalli ◽  
Michael Reinwald ◽  
Robert J. Eckersley ◽  
Joseph V. Hajnal
Keyword(s):  
Image Quality ◽  
Ultrasound Imaging ◽  
Imaging System ◽  
Spatial Location ◽  
Single Probe ◽  
Deep Imaging ◽  
Effective Aperture ◽  
Imaging Performance ◽  
Image Performance ◽  
Higher Sensitivity

Transducers with a larger aperture size are desirable in ultrasound imaging to improve resolution and image quality. A coherent multi-transducer ultrasound imaging system (CoMTUS) enables an extended effective aperture through the coherent combination of multiple transducers. In this study, the discontinuous extended aperture created by CoMTUS and its performance for deep imaging and through layered media are investigated by both simulations and experiments. Typical image quality metrics—resolution, contrast and contrast-to-noise ratio—are evaluated and compared with a standard single probe imaging system. Results suggest that the image performance of CoMTUS depends on the relative spatial location of the arrays. The resulting effective aperture significantly improves resolution, while the separation between the arrays may degrade contrast. For a limited gap in the effective aperture (less than a few centimetres), CoMTUS provides benefits to image quality compared to the standard single probe imaging system. Overall, CoMTUS shows higher sensitivity and reduced loss of resolution with imaging depth. In general, CoMTUS imaging performance was unaffected when imaging through a layered medium with different speed of sound values and resolution improved up to 80% at large imaging depths.

scholarly journals Temperature effect on performance of nanoparticle/surfactant flooding in enhanced heavy oil recovery

2019 ◽  
Vol 16 (6) ◽  
pp. 1387-1402 ◽  
Author(s):  
Sajjad Mahmoudi ◽  
Arezou Jafari ◽  
Soheila Javadian
Keyword(s):  
Temperature Effect ◽  
Oil Recovery ◽  
Temperature Increase ◽  
Surfactant Concentration ◽  
Sodium Dodecyl ◽  
Viscosity Reduction ◽  
Solution Stability ◽  
Oil Viscosity ◽  
Surfactant Solutions ◽  
The Stability

Abstract Recently, nanoparticles have been used along with surfactants for enhancing oil recovery. Although the recent studies show that oil recovery is enhanced using nanoparticle/surfactant solutions, some effective parameters and mechanisms involved in the oil recovery have not yet been investigated. Therefore, the temperature effect on the stability of nanoparticle/surfactant solutions and ultimate oil recovery has been studied in this work, and the optimal concentrations of both SiO2 nanoparticle and surfactant (sodium dodecyl sulfate) have been determined by the Central Composite Design method. In addition, the simultaneous effects of parameters and their interactions have been investigated. Study of the stability of the injected solutions indicates that the nanoparticle concentration is the most important factor affecting the solution stability. The surfactant makes the solution more stable if used in appropriate concentrations below the CMC. According to the micromodel flooding results, the most effective factor for enhancing oil recovery is temperature compared to the nanoparticle and surfactant concentrations. Therefore, in floodings with higher porous medium temperature, the oil viscosity reduction is considerable, and more oil is recovered. In addition, the surfactant concentration plays a more effective role in reservoirs with higher temperatures. In other words, at a surfactant concentration of 250 ppm, the ultimate oil recovery is improved about 20% with a temperature increase of 20 °C. However, when the surfactant concentration is equal to 750 ppm, the temperature increase enhances the ultimate oil recovery by only about 7%. Finally, the nanoparticle and surfactant optimum concentrations determined by Design-Expert software were equal to 46 and 159 ppm, respectively. It is worthy to note that obtained results are validated by the confirmation test.

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