scholarly journals Experimental evaluation of methodologies for single transient cavitation bubble generation in liquids

2021 ◽  
Vol 62 (8) ◽  
Author(s):  
Darjan Podbevšek ◽  
Žiga Lokar ◽  
Jure Podobnikar ◽  
Rok Petkovšek ◽  
Matevž Dular

AbstractSingle bubble dynamics are of fundamental importance for understanding the underlying mechanisms in liquid–vapor transition phenomenon known as cavitation. In the past years, numerous studies were published and results were extrapolated from one technique to another and further on to “real-world” cavitation. In the present paper, we highlight the issues of using various experimental approaches to study the cavitation bubble phenomenon and its effects. We scrutinize the transients bubble generation mechanisms behind tension-based and energy deposition-based techniques and overview the physics behind the bubble production. Four vapor bubble generation methods, which are most commonly used in single bubble research, are directly compared in this study: the pulsed laser technique, a high- and low-voltage spark discharge and the tube arrest method. Important modifications to the experimental techniques are implemented, demonstrating improvement of the bubble production range, control and repeatability. Results are compared to other similar techniques from the literature, and an extensive report on the topic is given in the scope of this work. Simple-to-implement techniques are presented and categorized herein, in order to help with future experimental design. Repeatability and sphericity of the produced bubbles are examined, as well as a comprehensive overview on the subject, listing the bubble production range and highlighting the attributes and limitation for the transient cavitation bubble techniques. Graphic abstract

2017 ◽  
Vol 19 (31) ◽  
pp. 20635-20640 ◽  
Author(s):  
Yang Shen ◽  
Kyuichi Yasui ◽  
Tong Zhu ◽  
Muthupandian Ashokkumar

The effect of bulk liquid viscosity on single bubble dynamics has been investigated using numerical simulations. The theoretical results obtained are supported by the published experimental data.


2021 ◽  
Vol 62 (5) ◽  
Author(s):  
Javad Eshraghi ◽  
Arezoo M. Ardekani ◽  
Pavlos P. Vlachos

2015 ◽  
Vol 113 (7) ◽  
pp. 2840-2844 ◽  
Author(s):  
Pariya Salami ◽  
Maxime Lévesque ◽  
Jean Gotman ◽  
Massimo Avoli

Low-voltage fast (LVF)- and hypersynchronous (HYP)-seizure onset patterns can be recognized in the EEG of epileptic animals and patients with temporal lobe epilepsy. Ripples (80–200 Hz) and fast ripples (250–500 Hz) have been linked to each pattern, with ripples predominating during LVF seizures and fast ripples predominating during HYP seizures in the rat pilocarpine model. This evidence led us to hypothesize that these two seizure-onset patterns reflect the contribution of neural networks with distinct transmitter signaling characteristics. Here, we tested this hypothesis by analyzing the seizure activity induced with the K+ channel blocker 4-aminopyridine (4AP, 4–5 mg/kg ip), which enhances both glutamatergic and GABAergic transmission, or the GABAA receptor antagonist picrotoxin (3–5 mg/kg ip); rats were implanted with electrodes in the hippocampus, the entorhinal cortex, and the subiculum. We found that LVF onset occurred in 82% of 4AP-induced seizures whereas seizures after picrotoxin were always HYP. In addition, high-frequency oscillation analysis revealed that 4AP-induced LVF seizures were associated with higher ripple rates compared with fast ripples ( P < 0.05), whereas picrotoxin-induced seizures contained higher rates of fast ripples compared with ripples ( P < 0.05). These results support the hypothesis that two distinct patterns of seizure onset result from different pathophysiological mechanisms.


Author(s):  
Saad Salman Khan

Electric power is flexible, easily controlled and is used in everyone's daily life. Humans can't use other form of energy except electric power because electric power, is one of the main factor to economic development, improved health care, poverty alleviation, and cleaner environment for a society. According to an estimate people more than 1.5 billion worldwide don't have sufficient access to electric power due to inaccessibility, electrification via traditional centralized form of grid was not a feasible option. This led to phenomenal research interest in microgrid based energy supply. Microgrids are low voltage network's that are designed to generate, transmit and distribute electrical energy. These grids accomplish specific goals such as cost reduction, CO2 emission reduction, reliability and diversification of energy sources. Microgrids are an ideal way to integrate renewable energy resources in the local community and allow consumer participation in an energy enterprise. In this chapter, we present a comprehensive overview of recent advancement in Microgrids.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Araz Sheibani Aghdam ◽  
Morteza Ghorbani ◽  
Gokberk Deprem ◽  
Fevzi Çakmak Cebeci ◽  
Ali Koşar

2020 ◽  
Vol 10 (7) ◽  
pp. 2281
Author(s):  
Santiago Camacho-Lopez ◽  
Carlos Andrés Zuñiga-Romero ◽  
Luis Felipe Devia-Cruz ◽  
Carolina Alvarez-Delgado ◽  
Marcos Antonio Plata-Sanchez ◽  
...  

Traditional applanation tonometry techniques lack the necessary accuracy and reliability for measuring the intraocular pressure (IOP), and there is still a need for a reliable technique for in vivo diagnosis. A single laser-induced cavitation bubble event was optically monitored in order to precisely measure the first collapse time of the cavitation bubble, which presents a direct dependence on the liquid pressure. This can certainly be done within the IOP range. We now extend the partial transmittance modulation (STM) technique to determine its feasibility for directly measuring the IOP by studying the nanosecond (ns) pulsed laser-induced cavitation bubble dynamics for an externally pressurized fresh ex vivo porcine eye. The results demonstrate that it is possible to monitor the IOP by detecting the light of a continuous-wave (CW) laser beam which is intensity modulated by the bubble itself. This technique currently presents a measurement resolution of about 4 mmHg in the 5 to 50 mmHg pressure range, indicating the feasibility of this approach for measuring IOP. This technique provides a direct measurement within the anterior eye chamber, avoiding common pitfalls in IOP diagnosis, such as errors due to patient movement, varying physical properties of the eye globe, or central cornea thickness (CCT) effects.


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