Editing Cavitation (section)

==Applications==

===Chemical engineering===
In industry, cavitation is often used to [[Homogenization (chemistry)|homogenize]], or mix and break down, suspended particles in a [[colloidal]] liquid compound such as paint mixtures or milk. Many industrial mixing machines are based upon this design principle. It is usually achieved through impeller design or by forcing the mixture through an annular opening that has a narrow entrance orifice with a much larger exit orifice. In the latter case, the drastic decrease in pressure as the liquid accelerates into a larger volume induces cavitation. This method can be controlled with [[hydraulic]] devices that control inlet orifice size, allowing for dynamic adjustment during the process, or modification for different substances. The surface of this type of mixing valve, against which surface the cavitation bubbles are driven causing their implosion, undergoes tremendous mechanical and thermal localized stress; they are therefore often constructed of extremely strong and hard materials such as [[stainless steel]], [[Stellite]], or even [[polycrystalline diamond]] (PCD).

Cavitating [[water purification]] devices have also been designed, in which the extreme conditions of cavitation can break down pollutants and organic molecules. Spectral analysis of light emitted in [[sonochemistry|sonochemical reactions]] reveal chemical and plasma-based mechanisms of energy transfer. The light emitted from cavitation bubbles is termed [[sonoluminescence]].

Use of this technology has been tried successfully in alkali refining of vegetable oils.<ref>{{cite web|url=http://www.ctinanotech.com/technology/edible-oil-refining|title=Edible Oil Refining|publisher=Cavitation Technologies, Inc.|access-date=2016-01-04|archive-date=2016-01-29 |archive-url=https://web.archive.org/web/20160129081235/http://www.ctinanotech.com/technology/edible-oil-refining|url-status=dead}}</ref><!-- Site down on 2016-01-07, but Google cache works. -->

Hydrophobic chemicals are attracted underwater by cavitation as the pressure difference between the bubbles and the liquid water forces them to join. This effect may assist in [[protein folding]].<ref>{{cite web | url = http://www.sandia.gov/news/resources/releases/2006/snap.html | website = Sandia National Laboratories | date = 2006-08-02 | access-date = 2007-10-17 | title = Sandia researchers solve mystery of attractive surfaces | archive-date = 2007-10-17 | archive-url = https://web.archive.org/web/20071017163015/http://sandia.gov/news/resources/releases/2006/snap.html | url-status = dead }}</ref>

===Biomedical===
Cavitation plays an important role for the destruction of [[kidney stone]]s in [[extracorporeal shock wave lithotripsy|shock wave lithotripsy]].<ref>{{Cite journal|pmc = 2442573|year = 2003|last1 = Pishchalnikov|first1 = Y. A|title = Cavitation Bubble Cluster Activity in the Breakage of Kidney Stones by Lithotripter Shock Waves|journal = Journal of Endourology|volume = 17|issue = 7|pages = 435–446|last2 = Sapozhnikov|first2 = O. A|last3 = Bailey|first3 = M. R|last4 = Williams Jr|first4 = J. C|last5 = Cleveland|first5 = R. O|last6 = Colonius|first6 = T|last7 = Crum|first7 = L. A|last8 = Evan|first8 = A. P|last9 = McAteer|first9 = J. A|pmid = 14565872|doi = 10.1089/089277903769013568}}</ref> Currently, tests are being conducted as to whether cavitation can be used to transfer large molecules into biological [[cell (biology)|cell]]s ([[sonoporation]]). Nitrogen cavitation is a method used in research to [[lysis|lyse]] cell membranes while leaving organelles intact.

Cavitation plays a key role in non-thermal, non-invasive fractionation of tissue for treatment of a variety of diseases<ref>{{cite web| url = http://www.histotripsy.umich.edu/| title = University of Michigan. ''Therapeutic Ultrasound Group, Biomedical Engineering Department, University of Michigan''.}}</ref> and can be used to open the [[Blood–brain barrier|blood-brain barrier]] to increase uptake of neurological drugs in the brain.<ref>{{Cite journal | doi=10.1038/srep33264| pmid=27630037| pmc=5024096| title=Focused Ultrasound-Induced Blood-Brain Barrier Opening: Association with Mechanical Index and Cavitation Index Analyzed by Dynamic Contrast-Enhanced Magnetic-Resonance Imaging| journal=Scientific Reports| volume=6| pages=33264| year=2016| last1=Chu| first1=Po-Chun| last2=Chai| first2=Wen-Yen| last3=Tsai| first3=Chih-Hung| last4=Kang| first4=Shih-Tsung| last5=Yeh| first5=Chih-Kuang| last6=Liu| first6=Hao-Li| bibcode=2016NatSR...633264C}}</ref>

Cavitation also plays a role in [[HIFU]], a thermal non-invasive treatment methodology for [[cancer]].<ref>{{Cite journal|last1=Rabkin|first1=Brian A.|last2=Zderic|first2=Vesna|last3=Vaezy|first3=Shahram|date=2005-07-01 |title=Hyperecho in ultrasound images of HIFU therapy: Involvement of cavitation|journal=Ultrasound in Medicine and Biology|volume=31|issue=7|pages=947–956|doi=10.1016/j.ultrasmedbio.2005.03.015|issn=0301-5629|pmid=15972200}}</ref>

In wounds caused by high velocity impacts (like for example bullet wounds) there are also effects due to cavitation. The exact wounding mechanisms are not completely understood yet as there is temporary cavitation, and permanent cavitation together with crushing, tearing and stretching. Also the high variance in density within the body makes it hard to determine its effects.<ref>{{Cite journal|last1=Stefanopoulos |first1=Panagiotis K.|last2=Mikros |first2=George|last3=Pinialidis|first3=Dionisios E.|last4=Oikonomakis |first4=Ioannis N.|last5=Tsiatis|first5=Nikolaos E.|last6=Janzon|first6=Bo|date=2009-09-01|title=Wound ballistics of military rifle bullets: An update on controversial issues and associated misconceptions |journal=The Journal of Trauma and Acute Care Surgery|volume=87|issue=3|pages=690–698|pmid=30939579 |s2cid=92996795|doi=10.1097/TA.0000000000002290}}</ref>

Ultrasound sometimes is used to increase bone formation, for instance in post-surgical applications.<ref>{{cite web|url=http://www.physiomontreal.com/Ultrasound.pdf |archive-url=https://web.archive.org/web/20030309225204/http://www.physiomontreal.com/Ultrasound.pdf |archive-date=2003-03-09 |url-status=live|title=Physio Montreal Article "Ultrasound"}}</ref>

It has been suggested that the sound of [[cracking joints|"cracking" knuckles]] derives from the collapse of cavitation in the [[synovial fluid]] within the joint.<ref>{{cite journal|last=Unsworth|first=A|author2=Dowson, D|author3=Wright, V|title='Cracking joints'. A bioengineering study of cavitation in the metacarpophalangeal joint|journal=Annals of the Rheumatic Diseases|date=July 1971|volume=30|issue=4|pages=348–58|pmid=5557778|doi=10.1136/ard.30.4.348|pmc=1005793}}</ref>

Cavitation can also form [[Ozone micro-nanobubbles]] which shows promise in dental applications.<ref>{{Cite journal |last1=Hauser-Gerspach |first1=Irmgard |last2=Vadaszan |first2=Jasminka |last3=Deronjic |first3=Irma |last4=Gass |first4=Catiana |last5=Meyer |first5=Jürg |last6=Dard |first6=Michel |last7=Waltimo |first7=Tuomas |last8=Stübinger |first8=Stefan |last9=Mauth |first9=Corinna |date=2011-08-13 |title=Influence of gaseous ozone in peri-implantitis: bactericidal efficacy and cellular response. An in vitro study using titanium and zirconia |url=http://dx.doi.org/10.1007/s00784-011-0603-2 |journal=Clinical Oral Investigations |volume=16 |issue=4 |pages=1049–1059 |doi=10.1007/s00784-011-0603-2 |pmid=21842144 |s2cid=10747305 |issn=1432-6981}}</ref>

===Cleaning===
In industrial cleaning applications, cavitation has sufficient power to overcome the particle-to-substrate adhesion forces, loosening contaminants. The threshold pressure required to initiate cavitation is a strong function of the pulse width and the power input. This method works by generating acoustic cavitation in the cleaning fluid, picking up and carrying contaminant particles away in the hope that they do not reattach to the material being cleaned (which is a possibility when the object is immersed, for example in an ultrasonic cleaning bath). The same physical forces that remove contaminants also have the potential to damage the target being cleaned.

=== Food and beverage ===

==== Eggs ====
Cavitation has been applied to egg pasteurization. A hole-filled rotor produces cavitation bubbles, heating the liquid from within. Equipment surfaces stay cooler than the passing liquid, so eggs do not harden as they did on the hot surfaces of older equipment. The intensity of cavitation can be adjusted, making it possible to tune the process for minimum protein damage.<ref>{{Cite news |url=https://www.npr.org/sections/thesalt/2017/12/11/569467444/how-the-food-industry-uses-cavitation-the-oceans-most-powerful-punch|title=How The Food Industry Uses Cavitation, The Ocean's Most Powerful Punch |work=NPR|access-date=2017-12-13}}</ref>

==== Vegetable oil production ====
Cavitation has been applied to vegetable oil degumming and refining since 2011 and is considered a proven and standard technology in this application. The implementation of hydrodynamic cavitation in the degumming and refining process allows for a significant reduction in process aid, such as chemicals, water and bleaching clay, use.<ref>{{cite web |title=Application of Controlled Flow Cavitation in Oil & Fats Processing |url=https://lacongress.aocs.org/Documents/Meetings/LACongress/Presentations/Litle.pdf |archive-url=https://web.archive.org/web/20220515081007/https://lacongress.aocs.org/Documents/Meetings/LACongress/Presentations/Litle.pdf |archive-date=2022-05-15 |url-status=live |access-date=2022-05-19 |publisher=arisdyne systems}}</ref><ref>{{Cite web|url=https://patents.justia.com/patent/10968414|title=US Patent for Methods for reducing soap formation during vegetable oil refining Patent (Patent # 10,968,414 issued April 6, 2021) - Justia Patents Search|website=patents.justia.com}}</ref><ref>{{Cite web|url=https://patents.justia.com/patent/10344246|title=US Patent for Oil degumming systems Patent (Patent # 10,344,246 issued July 9, 2019) - Justia Patents Search|website=patents.justia.com}}</ref><ref>{{Cite web|url=https://patents.justia.com/patent/9845442|title=US Patent for Method for degumming vegetable oil Patent (Patent # 9,845,442 issued December 19, 2017) - Justia Patents Search|website=patents.justia.com}}</ref><ref>{{Cite web|url=https://patents.justia.com/patent/9765279|title=US Patent for Method for reducing neutral oil losses during neutralization step Patent (Patent # 9,765,279 issued September 19, 2017) - Justia Patents Search|website=patents.justia.com}}</ref>

=== Biofuels ===

==== Biodiesel ====
Cavitation has been applied to Biodiesel production since 2011 and is considered a proven and standard technology in this application. The implementation of hydrodynamic cavitation in the transesterification process allows for a significant reduction in catalyst use, quality improvement and production capacity increase.<ref>{{cite web |url=http://www.biodieselmagazine.com/articles/8457/hero-bx-adopts-cavitation-tech-to-reduce-catalyst-use-monos |access-date=2022-05-19 |author=Arisdyne Systems |date=April 27, 2012 |title=Hero BX adopts cavitation tech to reduce catalyst use, monos |work=Biodiesel Magazine}}</ref><ref>{{Cite web|url=https://patents.justia.com/patent/9000244|title=US Patent for Process for production of biodiesel Patent (Patent # 9,000,244 issued April 7, 2015) - Justia Patents Search|website=patents.justia.com}}</ref><ref>{{Cite web|url=https://patents.justia.com/patent/20100175309|title=US Patent Application for PROCESS FOR IMPROVED BIODIESEL FUEL Patent Application (Application #20100175309 issued July 15, 2010) - Justia Patents Search|website=patents.justia.com}}</ref>