scholarly journals Comparing cleaning effects of gas and vapor bubbles in ultrasonic fields

2021 ◽  
pp. 105618
Author(s):  
Ryeol Park ◽  
Minsu Choi ◽  
Eun Hyun Park ◽  
Won-Jun Shon ◽  
Ho-Young Kim ◽  
...  
1990 ◽  
Vol 51 (C2) ◽  
pp. C2-603-C2-606 ◽  
Author(s):  
E. RIERA-FRANCO DE SARABIA ◽  
A. RAMOS-FERNANDEZ ◽  
L . GOMEZ-ULLATE

2016 ◽  
pp. 514-516
Author(s):  
Martin Bruhns

The massecuite circulates in a loop within the evaporating crystallizing vessel. The massecuite flows upwards through the heating tubes. In the room above the calandria the massecuite flow changes its direction to radial inwards and then to vertical downwards. An impeller in the central tube forces the circulation. Below the calandria the main direction of flow is radially outwards until threads of the massecuite stream enter the heating tubes in upwards direction. Within the tubes heat is transferred to the massecuite. At low temperature differences between heating steam and massecuite and higher levels of the massecuite in the crystallizer vapor bubbles are not found in the tubes. Vapor bubbles can be formed at a massecuite level in the crystallizer where the temperature of the massecuite is higher than the local boiling temperature of water, which depends on the local pressure (including the static pressure of the massecuite at this point) and the boiling point elevation of the mother liquor. The surface tension of the liquid is a resistance against the bubble formation, which has to be overcome by the local superheating i.e. the part of the enthalpy of the massecuite exceeding the local boiling temperature. The formation and the flow of the bubbles change the density of the massecuite/bubbles mixture and has an influence on the massecuite flow. The formation of a vapour bubble is connected with a local drop of the massecuite temperature which changes the local supersaturation. Today the heat transfer into the magma is quite well known but the process of bubble formation is quite unknown. Some basic considerations about the formation of bubbles and its influence on local supersaturation based on calculation of heat and mass balances and models of bubble formation are be given and discussed. Experiments for basic investigations are proposed.


1989 ◽  
Vol 66 (4) ◽  
pp. 1565-1570 ◽  
Author(s):  
H. L. W. Chan ◽  
K. S. Chiang ◽  
D. C. Price ◽  
J. L. Gardner

2015 ◽  
Vol 396 (6-7) ◽  
pp. 645-657 ◽  
Author(s):  
Gregory J. Czarnota

Abstract Cancer therapies result in the killing of cancer cells but remain largely ineffective, with most patients dying of their disease. The methodology described here is a new image-guided cancer treatment under development that relies on physical methods to alter tumour biology. It enhances tumour responses to radiation significantly by synergistically destroying tumour blood vessels using microbubbles. It achieves tumour specificity by confining the ultrasonic fields that stimulate microbubbles to tumour location only. By perturbing tumour vasculature and activating specific genetic pathways in endothelial cells, the technique has been demonstrated to sensitise the targeted tissues to subsequent therapeutic application of radiation, resulting in significantly enhanced cell killing through a ceramide-dependent pathway initiated at the cell membrane. The treatment reviewed here destroys blood vessels, significantly enhancing the anti-vascular effect of radiation and improving tumour cure. The significant enhancement of localised tumour cell kill observed with this method means that radiation-based treatments can be potentially made more potent and lower doses of radiation utilised. The technique has the potential to have a profound impact on the practice of radiation oncology by offering a novel and safe means of reducing normal tissue toxicity while at the same time significantly increasing treatment effectiveness.


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