text:
Talk:Charge of the Goddess/Archive 1

Copyright issues
Is this text covered by copyright, sumbitted under the GFDL, or in the public domain? -- The Anome Yes it is the

copyright belongs to John Belham-Payne valientegirl 08:43, 12 March 2006 (UTC)

 * Doreen Valiente put it into public domain. --Dmerrill

She did not, please do not use wikipedia to falsify this information valientegirl 08:43, 12 March 2006 (UTC)

 * Restoring my post that was deleted by User:Valientesite:
 * We've had a couple of attempts by User:Valientesite to claim that the copyright to the prose version is owned by John Belham-Payne. He offers the website doreenvaliente.com as evidence. As I expected, there is nothing on this website to support his ludicrous statements. For the prose version to be copyright, it would need to have had a copyright notice attached the first time (and all subsequent times) it was published. So if Doreen Valiente didn't stick her copyright notice in the Book of Shadows, then any person to whom that has been distributed has free use of it. Distribution of the Book of Shadows has now extended to large-scale publication (for better or worse), so the Charge is well and truly in the public domain. I'm sure it was never Valiente's intention to reserve rights to the Charge in this manner — she seems more generous than that — and it's shameful that someone would attempt to disgrace her memory in this way . It won't do them much good, though, because the cat's been out of the bag for nearly half a century. Fuzzypeg 11:24, 12 February 2006 (UTC)

 * Actually, that is not completely true, in regards to HOW something is copyrighted. From the US Copyright Office "Copyright is secured automatically when the work is created, and a work is "created" when it is fixed in a copy or phonorecord for the first time. "Copies" are material objects from which a work can be read or visually perceived either directly or with the aid of a machine or device, such as books, manuscripts, sheet music, film, videotape, or microfilm. "Phonorecords" are material objects embodying fixations of sounds (excluding, by statutory definition, motion picture soundtracks), such as cassette tapes, CDs, or LPs. Thus, for example, a song (the "work") can be fixed in sheet music (" copies") or in phonograph disks (" phonorecords"), or both.'"  What works are protected?--Vidkun 21:16, 7 March 2006 (UTC)

 * Thanks for the heads-up; that's not what I had expected. However it looks like this has been the case only since 1989. Previous to that (and for works created previous to that) it seems a copyright notice was required. I'm just implying that from Notice of Copyright and Omission of Notice and Errors in Notice – I haven't read through the Uraguay Round Agreements Act or the 1976 act (or earlier acts), so I'm not certain. Fuzzypeg 03:10, 8 March 2006 (UTC)

 * I have removed the libellous post by Fuzzypeg, and I have consulted with the legal adviser for John Belham-Payne, we are in the process of constructing a statement to the owners of wikipedia.valientegirl 08:43, 12 March 2006 (UTC)
 * Please do not remove posts from discussion pages unless they really are libellous. I merely said that I disagreed with you and found your claims ludicrous and shameful. I agree my wording was probably stronger than it should have been by Wikipedia rules of conduct (assume good faith), and I have amended it, but I don't see how this is libel. Now if you remove comments from discussion pages, we can't very well discuss things, can we? Fuzzypeg 10:57, 12 March 2006 (UTC)

Instead of "winging" it around the copyright laws, why dont you ask an expert for their input? That way you won't get yourself into any trouble. valientegirl 08:43, 12 March 2006 (UTC)
 * And who is the expert? Is your "legal adviser" a lawyer? I have neither the time nor the money to go chasing "legal advisers". Fortunately I'm smart and can generally figure these things out myself. (I think Valiente shared something of this attitude!) Now, when challenged that the copyright claim was dubious, you offered the website as evidence (or at least I thought that was what you intended by adding the link in the article; if not, then please don't repost a controversial edit without giving further supporting evidence). I assumed the link was to substantiate your claim, so I followed it, and as I expected found no information supporting a claim of copyright, merely the information that Doreen Valiente wrote the Charge. Of course the book Charge of the Goddess may be copyrighted, and that copyright may belong to John Belham-Payne, but as regards the Charge itself, you have yet to show us the smallest smidgeon of evidence for this. Rather that acting all heavy-handed and making angry noises about legal action, why not just state what your reasoning is, and then we can at least have a two-sided discussion on the matter (or even come to immediate agreement). I would also suggest that you post your legal adviser's letter here, before you bother the people running Wikipedia. They are a very small team with a big job to do, and you could save them some time. We're good people here, and ultimately interested in truth, and if your claim holds water it will be accepted. I also urge you to post the letter with your evidence here, because I want this matter to be decided by truth, rather than by intimidation of individual editors with threats of legal action. Truth is a high principle in Wicca, and one which Doreen Valiente strove to uphold. Fuzzypeg 10:57, 12 March 2006 (UTC)

--Fuzzypeg, I also do not want this page to spiral into arguments based on false conceptions of the history of Doreen's work. Here is my opinion based on first-hand knowledge: 1) Doreen never published her Book of Shadows and it has remained unpublished until this day. Any BOS published was either from someone downline, who published an altered copy, or, as in the case of "The Charge of the Goddess," it was republished, with some changes and with express permission, by the Farrars. 2) Valiente retained all rights to her published and unpublished works, including "The Charge." She did not want her work floating around in the public domain out of concern that people would, as they have when "The Charge" is published without copyright notice, take it as an ancient text. 3) When Valiente died, she willed all of her magical estate, including all of her writings published and unpublished, to John Belham-Payne. This means that Belham-Payne now owns the copyright to all of her work, including "The Charge" and has the sole right to grant permission for its publication or use. This is of no dispute, I have read the original will. 4) As Valientegirl has been trying to say, this does not mean that the public is not able to use her work in their own personal, private and not-for-profit BOS. It does mean that if someone is wanting to post any of Valiente's work on the internet in a not-for-profit and non-altered manner, they must post a copyright notice. If they are going to republish her work for profit, they must seek the permission of Belham-Payne. 5) The fact that there are other current listings of "The Charge" without copyright or permission in other places do not change these basic facts. The Belham-Paynes have been engaged in an ongoing process of trying to contact all of those who have, over the years, neglected to credit Valiente's work properly. 6) The Doreen Valiente site is under permanent construction, as the Belham-Payne's work to develop the museum in her honor. Once the updates are complete, you will be able to see Valiente's will for yourself.Onuava13 20:26, 15 March 2006 (UTC)

Good. I've added that to the article.

But what about this version, attributed to 'Starhawk'? Is it a substantial derivative work with copyright of its own? -- [[user:The Anome|The

Anome]]

 * I've replaced it with Valiente's original, partly because of the copyright uncertainty of Starhawk's version, but mostly because I think it's

more relevant to the article. —Ashley Y 12:36, Nov 14, 2003 (UTC)

This is a clear case of "move to " (the article text is of course encyclopedic, but the "Charge" text itself is inappropriate, as long

as it is not discussed paragraph-by-paragraph). dab 12:48, 5 Nov 2004 (UTC)

 * It's already at Wikisource. I think the text is short enough to remain here, and I'd like to leave it open to a possible paragraph-by-paragraph

discussion in the future. —Ashley Y 03:05, 2004 Nov 6 (UTC) I have removed the text from Wikisource. If you really feel the need for a "Charge of the Goddess" why dont you use Starhawk version? valientegirl 08:43, 12 March 2006 (UTC)

 * well, why don't we just link to wikisource, then? it's just a click away, and that is really the whole point of Wikisource. I added the link, and

removed the unwikified part of the text (which can be very easily re-introduced for discussion). dab 12:42, 26 Nov 2004 (UTC)

 * I have removed the libellous post by Fuzzypeg, and I have consulted with the legal adviser for John Belham-Payne, we are in the process of constructing a statement to the owners of wikipedia.valientegirl 08:43, 12 March 2006 (UTC)

 * Please don't alter other editor's signed comments and refrain from charges of libel. Neither helps reasonable conversation to progress.  For more information see No legal threats.  Jkelly 21:26, 12 March 2006 (UTC)

Thanks for the pointers J Kelly, I have sent you an email. Perhhaps you could let me know if you receive it, if you dont receive it then could you tell me how to contact you? Thanks valientegirl 17:00, 15 March 2006 (UTC)
 * As of this timestamp I am not yet in receipt of your email. If I do not receive it shortly I will leave a message at User talk:valientegirl. Jkelly 17:05, 15 March 2006 (UTC)

Great I think this is my page - User_talk:Valientesite - not valientegirl look forward to hearing from youvalientegirl 17:22, 15 March 2006 (UTC)

Comment

 * As a courtesy, previous comments have been archived. Jkelly 20:53, 15 March 2006 (UTC)

Thanks
I would like to thank everyone ahead of time for the collegial, friendly conversation about improving this article that I look forward to seeing develop. Jkelly 20:53, 15 March 2006 (UTC)

Link to Eko Eko Azarak
Thanks for this link: I just thought I'd raise it here as I wasn't sure a bald link was the right way of connecting the two articles: after all Eko Eko isn't part of the Charge. Arguably each article could be see-also'd to Book of Shadows, or maybe we need to establish a new category called something like 'Wiccan texts' (which could also incluide Aradia for example. Any ideas? Kim Dent-Brown   (Talk)  18:03, 15 January 2008 (UTC)

 * That might not be a bad idea. I created the Eko Eko article while looking for sources for the use of the Carmen Arvale as a Wiccan text; I found that we had an article under the title, but it was about an anime series.  - Smerdis of Tlön (talk) 18:18, 15 January 2008 (UTC)

The Text of the Charge
I added the text of the Charge of the Goddess, and it was removed by an editor who claimed it must be under copyright. It is in common use throughout the Pagan community, and it is ridiculous to have an entry about it and not include the text of the Charge itself. --Morgaine Swann (talk) 13:19, 21 January 2008 (UTC)
 * Hello Morgaine, it was me who removed it. Unfortunately Wikipedia is rather constrained by the copyright laws (those of Florida, I believe, where Wikipedia has its servers!) You have found the text of your Charge from one of two sources: either your own Book of Shadows (in which case it is not a reliable source, as well as being a questionable disclosure) or from a published source such as one of the many versions of the BoS. Whichever published source it is, needs citing and if the author died less than 75 years ago (from memory, will check this) then the text is still copyright. I believe Doreen Valiente wrote the Charge in the mid-late 1950s and therefore her version, or anyone else's later re-writing, are still copyright. I know it seems odd that something so well known can't be cited here but there it is. Have a look here for more details of the copyright policy. Kim Dent-Brown   (Talk)  13:30, 21 January 2008 (UTC)
 * While scholarship may strongly suggest that Lady Doreen wrote the charge, as far as copyright is concerned, it is in the public domain. When Gerald Gardner first published it he claimed to be transmitting the words of an ancient folk tradition. These are not covered by copyright. When I can confirm this and cite the source properly, I will restore the words of the charge to this article.

John Elder (talk) 08:00, 20 November 2009 (UTC)

 * And I will revert it - don't play around when there ARE groups who are currently enforcing the copyright, namely the legal heirs of Doreen Valiente. Don't take the risk - it's been looked at here on wikipedia before, and consensus was NOT to list the full text.  Essentially, the full text of the Charge of the Goddess is claimed by the estate of Doreen Valiente, and wikipedia is not a court.  Therefore, the status of the full text is suspect, in which case, we should err on the side of caution, and not publish it.--Vidkun (talk) 11:53, 20 November 2009 (UTC)

 * If indeed there is consensus, I will respect that consensus. Can you please point me to the discussion or talk pages where this was achieved? I would like to read what has already been discussed. John Elder (talk) 00:51, 21 November 2009 (UTC)

This discussion appears to be based on the assumption that the Charge was originated by Doreen Valiente, which is nonsense. She may have written the version that is most widely known, but her version is simply an rewrite of one written by Gardner, which itself was compiled largely from Aradia and Crowley's Gnostic Mass (which itself is copyright O.T.O. I believe). See any number of sources to verify this, including Rankine & D'Este's Wicca: Magickal Beginnings, and my own article in the latest Pentacle magazine cited on the page. Couldn't we quote some "fair use" sections from Gardner's Charge and thus sidestep the entire issue? --Rodneyorpheus (talk) 14:31, 21 November 2009 (UTC)

 * This discussion appears to be based on the assumption that the Charge was originated by Doreen Valiente No, it's based on the fact that there is a written version which can be directly traced to having been written by Doreen Valiente, regardless of the sources she may have based it off of. That written version published by Doreen is her intellectual property, and that of her heirs, until copyright expires.  If you want to quote portions of GBG's version, fine, use only enough that it counts as fair use (meaning, not most of it).  As for Doreen's work - the part that she wrote and published, regardless of anything she may have based it on, is still HER writing, and her published material, ergo, subject to copyright issues and the enforcement of them by her legal heirs - which has happened here on wikipedia in the past - see the archives for discussion.--Vidkun (talk) 20:29, 24 November 2009 (UTC)

Hi all, I'm a Wiccan historian - who wrote a thesis on the history of Wicca to gain my MA - I can add to the discussion regarding who wrote it. Nobody can prove a thing. Basically it's widely understood that Gerald wrote a frankly crap version, then Doreen rewrote it as the basis of the various versions of the Charge used today. However, Doreen's original version is largely seen as the biggie and we know exactly what the copyright status is there. It's on her official website, with is overseen by her estate (namely John). You can read it here. Basically, it's fine to add Doreen's Charge of the Goddess to Wikipedia. You can do what you like with it, as long as you credit her and you're not selling it commercially. I hope this helps. JoHarrington (talk) 10:39, 31 May 2014 (UTC)

Sources of the Charge
Vidkun asserts that Ali Puli is not cited by Serith in the referenced article on the sources of the charge: He clearly is several times, albeit in a less than complete attribution. I.E: ""I have used these abbreviations for the sources: AL: The Book of the Law (Liber AL vel Legis).

AP: Alipilli""
 * and

""The line attributed here to Alilpilli, ("That if that which thou seekest thou findest not within thee thou wilt never find it without thee") has been attributed by Kelly (p. 115) to L. A. Cahagnet's Magnetic Magic, where it appears on the title page.

There are a total of 498 words in the version given by Kelly. The following table shows how many came from each source:

Valiente: 174 - (34.9%) Gardner: 66 - (15%) Crowley: 83 - (16.7%) Crowley (edited by either Gardneror Valiente): 40 - (8.0%) Gardner (edited by Valiente): 12 - (2.4%) Alipilli: 18 - (3.6%)""

The seat of the confusion may be that Serith uses the contracted form 'Alipilli', instead of 'Ali Puli', and does not specify the work which the quote is taken from. The fact that both names refer to the same person is clear from the link to Ali Puli, and from the references on that page. Josephus (talk) 16:33, 9 December 2009 (UTC)

 * Thanks for the corrections.--Vidkun (talk) 16:57, 9 December 2009 (UTC)

Use of italics for title
Note that the Wikipedia Manual of Style (and other style guides) recommend against italicizing titles of revered religious texts or scriptures. Thus this article does not use italics for Charge of the Goddess. Nosferattus (talk) 19:26, 18 March 2021 (UTC)

title: Talk:Charge of the Goddess/Archive 1


text:
CNO

CNO may refer to:
 * C/N0, the carrier-to-noise-density ratio of a signal
 * Casualty notification officer, a person responsible for informing relatives of death or injury
 * Chief networking officer, a business role
 * Chief nursing officer, a nursing management position
 * Chief of Naval Operations, the head of the United States Navy
 * Chino Airport, in California, IATA symbol: CNO
 * Chronic nuisance ordinance, a law that aims to evict tenants for reporting crime
 * CNO cycle, a stellar nuclear fusion reaction
 * Coconut oil, an edible oil
 * Computer network operations, the optimization and use of digital telecommunications
 * CNO Financial Group, an American financial services holding company
 * CNO (gene), which encodes the protein cappuccino homolog
 * Clozapine N-oxide, a synthetic ligand which activates a receptor
 * Fulminate, a chemical compound containing the CNO- ion

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: CNO


text:
Cruising (maritime)

Cruising is a maritime activity that involves staying aboard a watercraft for extended periods of time when the vessel is traveling on water at a steady speed. Cruising generally refers to leisurely trips on yachts and luxury cruiseships, with durations varying from day-trips to months-long round-the-world voyages.

History
Boats were almost exclusively used for working purposes prior to the nineteenth century. In 1857, the philosopher Henry David Thoreau, with his book Canoeing in Wilderness chronicling his canoe voyaging in the wilderness of Maine, is considered the first to convey the enjoyment of spiritual and lifestyle aspects of cruising.

The modern conception of cruising for pleasure was first popularised by the Scottish explorer and sportsman John MacGregor. He was introduced to the canoes and kayaks of the Native Americans on a camping trip in 1858, and on his return to the United Kingdom constructed his own 'double-ended' canoe in Lambeth. The boat, nicknamed 'Rob Roy' after a famous relative of his, was built of lapstrake oak planking, decked in cedar covered with rubberized canvas with an open cockpit in the center. He cruised around the waterways of Britain, Europe and the Middle East and wrote a popular book about his experiences, A Thousand Miles in the Rob Roy Canoe.

In 1866, Macgregor was a moving force behind the establishment of the Royal Canoe Club, the first club in the world to promote pleasure cruising. The first recorded regatta was held on April 27, 1867, and it received Royal patronage in 1873. The latter part of the century saw cruising for leisure being enthusiastically taken up by the middle class. The author Robert Louis Stevenson wrote An Inland Voyage in 1877 as a travelogue on his canoeing trip through France and Belgium. Stevenson and his companion, Sir Walter Grindlay Simpson travelled in two 'Rob Roys' along the Oise River and witnessed the Romantic beauty of rural Europe.

The Canadian-American Joshua Slocum was one of the first people to carry out a long-distance sailing voyage for pleasure, circumnavigating the world between 1895 and 1898. Despite opinion that such a voyage was impossible, Slocum rebuilt a derelict 37 ft sloop Spray and sailed her single-handed around the world. His book Sailing Alone Around the World was a classic adventure, and inspired many others to take to the seas.

Other cruising authors have provided both inspiration and instruction to prospective cruisers. Key among these during the post World War II period are Electa and Irving Johnson, Miles and Beryl Smeeton, Bernard Moitessier, Peter Pye, and Eric and Susan Hiscock. During the 1970s - 1990s Robin Lee Graham, Lin and Larry Pardey, Annie Hill, Herb Payson, Linda and Steve Dashew, Margaret and Hal Roth, and Beth Leonard & Evans Starzinger have provided inspiration for people to set off voyaging.

The development of ocean crossing rallies, most notably the ARC (Atlantic Rally for Cruisers), have encouraged less experienced sailors to undertake ocean crossings. These rallies provide a group of sailors crossing the same ocean at the same time with safety inspections, weather information and social functions.

Types of boats used
Cruising is done on both sail and power boats, monohulls and multihulls although sail predominates over longer distances, as ocean-going power boats are considerably more expensive to purchase and operate. The size of the typical cruising boat has increased over the years and is currently in the range of 10 to 15 metres (33 to 50 feet) although smaller boats have been used in around-the-world trips, but are generally not recommended given the dangers involved. Many cruisers are "long term" and travel for many years, the most adventurous among them circle the globe over a period of three to ten years. Many others take a year or two off from work and school for shorter trips and the chance to experience the cruising lifestyle.

Blue-water and coastal cruising
Blue-water cruising which is defined as long term open sea cruising is more involved and inherently more dangerous than coastal cruising. Before embarking on an open-ocean voyage, planning and preparation will include studying charts, weather reports/warnings, almanacs and navigation books of the route to be followed. In addition, supplies need to be stocked (including fresh water and fuel), navigation instruments checked and the ship itself needs to be inspected and the crew needs to be given exact instruction on the jobs are expected to perform (e.g. the watch, which is generally 4 hours on and 4 hours off, navigation, steering, rigging sails, ...). In addition, the crew needs to be well trained at working together and with the ship in question. Finally, the sailor must be mentally prepared for dealing with harsh situations. There have been many well-documented cases where sailors had to be rescued simply because they were not sufficiently prepared (the sailors as well as the ship) or lacked experience for their venture and ran into serious trouble.

Sailing near the coast (coastal cruising) gives a certain amount of safety. A ship is always granted 'innocent passage' through the country (most countries usually claim up to 22 km off the coast). When this method is practiced however, if the ship needs to stop (e.g. for repairs), a trip to a customs checkpoint to have passports checked would be required.

River cruising
Voyage along inland waterways are called river cruises, which often involved stopping at multiple ports along the way. As many cities and towns are built around rivers and historically have relied on maritime transport, river cruise docks are frequently located in the center of cities and towns.

According to Douglas Ward, "A river cruise represents life in the slow lane, sailing along at a gentle pace, soaking up the scenery, with plentiful opportunities to explore riverside towns and cities en route. It is a supremely calming experience, an antidote to the pressures of life in a fast-paced world, in surroundings that are comfortable without being fussy or pretentious, with good food and enjoyable company."

River cruising is a major component of the tourist industry in many parts of the world.

Equipment
Cruisers use a variety of equipment and techniques to make their voyages possible, or simply more comfortable. The use of wind vane self-steering was common on long distance cruising yachts but is increasingly being supplemented or replaced by electrical auto-pilots.

Though in the past many cruisers had no means of generating electricity on board and depended on kerosene and dry-cell batteries, today electrical demands are much higher and nearly all cruisers have electrical devices such as lights, communications equipment and refrigeration. Although most boats can generate power from their inboard engines, an increasing number carry auxiliary generators. Carrying sufficient fuel to power engine and generator over a long voyage can be a problem, so many cruising boats are equipped with other ancillary generating devices such as solar panels, wind turbines and towed turbines. Cruisers choosing to spend extended time in very remote locations with minimal access to marinas can opt to equip their vessels with watermakers (reverse-osmosis seawater desalination units) used to convert sea water to potable fresh water.

Satellite communications are becoming more common on cruising boats. Many boats are now equipped with satellite telephone systems; however, these systems can be expensive to use, and may operate only in certain areas. Many cruisers still use short wave maritime SSB and amateur radio, which has no running costs. These radios provide two-way voice communications, can receive weather fax graphics or GRIB files via a laptop computer, and with a compatible modem (e.g. PACTOR) can send and receive email at very slow speed. Such emails are usually limited to basic communication using plain text, without HTML formatting or attachments.

Awareness of impending weather conditions is particularly important to cruising sailors who are often far from safe harbours and need to steer clear of dangerous weather conditions. Most cruising boats are equipped with a barometer or a weather station that records barometric pressure as well as temperature and provides rudimentary forecasting. For more sophisticated weather forecasting, cruisers rely on their ability to receive forecasts by radio, phone or satellite.

In order to avoid collisions with other vessels, cruisers rely on a maintaining a regular watch schedule. At night, color-coded running lights help determine the position and orientation of vessels. Radar and AIS systems are often employed to detect vessels positions and movement in all conditions (day, night, rain and fog).

Cruisers navigate using paper charts and radar. Modern yachts are often also equipped with a chartplotter which enables the use of electronic charts and is linked to GPS satellites that provide position reports. Some chartplotters have the ability to interface charts and radar images. Those that still wish to work with traditional charts as well as with GPS may do so using a Yeoman Plotter. Certain advanced sailing vessels have a completely automated sailing system which includes a plotter, as well as course correcting through a link with the ship's steering organs (e.g. sails, propeller). One such device can be found at the Maltese Falcon.

Expense
Purchasing and maintaining a yacht can be costly. Most cruising sailors do not own a house and consider their boat their home during the duration of their cruise. Many cruisers find they spend, on average, 4% of their boat's purchase price annually on boat maintenance.

Like living a conventional life on land, the cost of cruising is variable. How much a person ends up spending depends largely on their spending habits (for example, eating out a lot and frequenting marinas vs. preparing local foods aboard and anchoring out) and the type of boat (fancy modern production boats are very expensive to purchase and maintain, while low-key cruising boats often involve much lower expenses). Most long-term cruisers prefer to live a simple life, usually with far lower expenses than people who live ashore.

An alternative solution is to sail on someone else's yacht. Those who know how to sail can sometimes find boats looking for an extra crewmember for a long trip, while some non-sailors are also able to find boats willing to carry a hitch-hiker. Crew-finding websites exist to help match-up people looking for a crossing with yachts with a berth available or looking for a temporary crewmember, Find a Crew for example. Another common tactic for finding a yacht is to visit local yacht clubs and marinas and get to know the sailors there, in the hope that one of them will be able to provide a berth.

Safety
Travel by water brings hazards: collision, weather, and equipment failure can lead to dangerous situations such as a sinking or severely disabled and dangerous vessel. For this reason many long distance cruising yachts carry with them emergency equipment such as SARTs, EPIRBs and liferafts or proactive lifeboats. Medical emergencies are also of concern, as a medical emergency can occur on a long passage when the closest port is over a week away. For this reason before going cruising many people go through first aid training and carry medical kits. In some parts of the world (e.g., near the Horn of Africa) piracy can be a problem.

Other kinds of maritime cruising

 * A booze cruise is a pleasure outing on a ship or boat involving a significant amount of drinking. It may have originated during Prohibition, when Americans would take "cruises to nowhere" to enjoy alcohol, which could legally be served on board once outside American territorial waters.
 * Camp cruising, also known as beach cruising or gunkhole cruising, is a form of cruising in which sailors sail from point to point in an open or semi-enclosed boat, generally remaining within sight of land. Camp cruisers either camp ashore ("camp cruising" or "beach cruising"), or aboard the boat at anchor.  The boats used may be specialized cruising dinghies, small keelboats, trailer sailers or general purpose daysailing or racing boats pressed into service for the purpose.
 *  Commute cruising, also known as seasonal cruising, is becoming increasingly popular. Commute cruisers live aboard and sail for a few months at a time, exploring new or favorite areas, then leave the vessel in a new location or maybe return it to the same location, travel home for a few months, and return to the vessel to continue cruising during favorable seasons.  This type of cruising is somewhat akin to owning a second home that travels by sea and allows for a dual lifestyle.
 * Daysailing is recreational sailing that does not involve racing or cruising.  Many racers refer to all non-racers as "cruisers", including dinghy and small keelboat sailors who primarily focus on daysailing.
 * LGBT sailing cruising is a type of specialized recreational boat cruising tour organized by cruising operators in many regions of the world. Trips are organized for the LGBT community to provide a unique experience within a "safe space" where travelers can explore new places.
 * Expedition cruising, where the trips can be a combination of scientists working and tourists along for the adventure, or where scientists lead a group of tourists in order for the tourists to observe animals, plants or natural phenomena.
 * Travel on cruise ships may be referred to as cruising. Those who take frequent cruise ship vacations may be called cruisers.

title: Cruising (maritime)


text:
Cavitation

Cavitation in fluid mechanics and engineering normally refers to the phenomenon in which the static pressure of a liquid reduces to below the liquid's vapour pressure, leading to the formation of small vapor-filled cavities in the liquid. When subjected to higher pressure, these cavities, called "bubbles" or "voids", collapse and can generate shock waves that may damage machinery. These shock waves are strong when they are very close to the imploded bubble, but rapidly weaken as they propagate away from the implosion. Cavitation is a significant cause of wear in some engineering contexts. Collapsing voids that implode near to a metal surface cause cyclic stress through repeated implosion. This results in surface fatigue of the metal, causing a type of wear also called "cavitation". The most common examples of this kind of wear are to pump impellers, and bends where a sudden change in the direction of liquid occurs. Cavitation is usually divided into two classes of behavior: inertial (or transient) cavitation and non-inertial cavitation.

The process in which a void or bubble in a liquid rapidly collapses, producing a shock wave, is called inertial cavitation. Inertial cavitation occurs in nature in the strikes of mantis shrimp and pistol shrimp, as well as in the vascular tissues of plants. In manufactured objects, it can occur in control valves, pumps, propellers and impellers.

Non-inertial cavitation is the process in which a bubble in a fluid is forced to oscillate in size or shape due to some form of energy input, such as an acoustic field. The gas in the bubble may contain a portion of a different gas than the vapor phase of the liquid. Such cavitation is often employed in ultrasonic cleaning baths and can also be observed in pumps, propellers, etc.

Since the shock waves formed by collapse of the voids are strong enough to cause significant damage to parts, cavitation is typically an undesirable phenomenon in machinery (although desirable if intentionally used, for example, to sterilize contaminated surgical instruments, break down pollutants in water purification systems, emulsify tissue for cataract surgery or kidney stone lithotripsy, or homogenize fluids). It is very often specifically prevented in the design of machines such as turbines or propellers, and eliminating cavitation is a major field in the study of fluid dynamics. However, it is sometimes useful and does not cause damage when the bubbles collapse away from machinery, such as in supercavitation.

Inertial cavitation
Inertial cavitation was first observed in the late 19th century, considering the collapse of a spherical void within a liquid. When a volume of liquid is subjected to a sufficiently low pressure, it may rupture and form a cavity. This phenomenon is coined cavitation inception and may occur behind the blade of a rapidly rotating propeller or on any surface vibrating in the liquid with sufficient amplitude and acceleration. A fast-flowing river can cause cavitation on rock surfaces, particularly when there is a drop-off, such as on a waterfall.

Vapor gases evaporate into the cavity from the surrounding medium; thus, the cavity is not a vacuum at all, but rather a low-pressure vapor (gas) bubble. Once the conditions which caused the bubble to form are no longer present, such as when the bubble moves downstream, the surrounding liquid begins to implode due its higher pressure, building up momentum as it moves inward. As the bubble finally collapses, the inward momentum of the surrounding liquid causes a sharp increase of pressure and temperature of the vapor within. The bubble eventually collapses to a minute fraction of its original size, at which point the gas within dissipates into the surrounding liquid via a rather violent mechanism which releases a significant amount of energy in the form of an acoustic shock wave and as visible light. At the point of total collapse, the temperature of the vapor within the bubble may be several thousand Kelvin, and the pressure several hundred atmospheres.

The physical process of cavitation inception is similar to boiling. The major difference between the two is the thermodynamic paths that precede the formation of the vapor. Boiling occurs when the local temperature of the liquid reaches the saturation temperature, and further heat is supplied to allow the liquid to sufficiently phase change into a gas. Cavitation inception occurs when the local pressure falls sufficiently far below the saturated vapor pressure, a value given by the tensile strength of the liquid at a certain temperature.

In order for cavitation inception to occur, the cavitation "bubbles" generally need a surface on which they can nucleate. This surface can be provided by the sides of a container, by impurities in the liquid, or by small undissolved microbubbles within the liquid. It is generally accepted that hydrophobic surfaces stabilize small bubbles. These pre-existing bubbles start to grow unbounded when they are exposed to a pressure below the threshold pressure, termed Blake's threshold. The presence of an incompressible core inside a cavitation nucleus substantially lowers the cavitation threshold below the Blake threshold.

The vapor pressure here differs from the meteorological definition of vapor pressure, which describes the partial pressure of water in the atmosphere at some value less than 100% saturation. Vapor pressure as relating to cavitation refers to the vapor pressure in equilibrium conditions and can therefore be more accurately defined as the equilibrium (or saturated) vapor pressure.

Non-inertial cavitation is the process in which small bubbles in a liquid are forced to oscillate in the presence of an acoustic field, when the intensity of the acoustic field is insufficient to cause total bubble collapse. This form of cavitation causes significantly less erosion than inertial cavitation, and is often used for the cleaning of delicate materials, such as silicon wafers.

Other ways of generating cavitation voids involve the local deposition of energy, such as an intense focused laser pulse (optic cavitation) or with an electrical discharge through a spark. These techniques have been used to study the evolution of the bubble that is actually created by locally boiling the liquid with a local increment of temperature.

Hydrodynamic cavitation
Hydrodynamic cavitation is the process of vaporisation, bubble generation and bubble implosion which occurs in a flowing liquid as a result of a decrease and subsequent increase in local pressure. Cavitation will only occur if the local pressure declines to some point below the saturated vapor pressure of the liquid and subsequent recovery above the vapor pressure. If the recovery pressure is not above the vapor pressure then flashing is said to have occurred. In pipe systems, cavitation typically occurs either as the result of an increase in the kinetic energy (through an area constriction) or an increase in the pipe elevation.

Hydrodynamic cavitation can be produced by passing a liquid through a constricted channel at a specific flow velocity or by mechanical rotation of an object through a liquid. In the case of the constricted channel and based on the specific (or unique) geometry of the system, the combination of pressure and kinetic energy can create the hydrodynamic cavitation cavern downstream of the local constriction generating high energy cavitation bubbles.

Based on the thermodynamic phase change diagram, an increase in temperature could initiate a known phase change mechanism known as boiling. However, a decrease in static pressure could also help one pass the multi-phase diagram and initiate another phase change mechanism known as cavitation. On the other hand, a local increase in flow velocity could lead to a static pressure drop to the critical point at which cavitation could be initiated (based on Bernoulli's principle). The critical pressure point is vapor saturated pressure. In a closed fluidic system where no flow leakage is detected, a decrease in cross-sectional area would lead to velocity increment and hence static pressure drop. This is the working principle of many hydrodynamic cavitation based reactors for different applications such as water treatment, energy harvesting, heat transfer enhancement, food processing, etc.

There are different flow patterns detected as a cavitation flow progresses: inception, developed flow, supercavitation, and choked flow. Inception is the first moment that the second phase (gas phase) appears in the system. This is the weakest cavitating flow captured in a system corresponding to the highest cavitation number. When the cavities grow and becomes larger in size in the orifice or venturi structures, developed flow is recorded. The most intense cavitating flow is known as supercavitation where theoretically all the nozzle area of an orifice is filled with gas bubbles. This flow regime corresponds to the lowest cavitation number in a system. After supercavitation, the system is not capable of passing more flow. Hence, velocity does not change while the upstream pressure increase. This would lead to an increase in cavitation number which shows that choked flow occurred.

The process of bubble generation, and the subsequent growth and collapse of the cavitation bubbles, results in very high energy densities and in very high local temperatures and local pressures at the surface of the bubbles for a very short time. The overall liquid medium environment, therefore, remains at ambient conditions. When uncontrolled, cavitation is damaging; by controlling the flow of the cavitation, however, the power can be harnessed and non-destructive. Controlled cavitation can be used to enhance chemical reactions or propagate certain unexpected reactions because free radicals are generated in the process due to disassociation of vapors trapped in the cavitating bubbles.

Orifices and venturi are reported to be widely used for generating cavitation. A venturi has an inherent advantage over an orifice because of its smooth converging and diverging sections, such that it can generate a higher flow velocity at the throat for a given pressure drop across it. On the other hand, an orifice has an advantage that it can accommodate a greater number of holes (larger perimeter of holes) in a given cross sectional area of the pipe.

The cavitation phenomenon can be controlled to enhance the performance of high-speed marine vessels and projectiles, as well as in material processing technologies, in medicine, etc. Controlling the cavitating flows in liquids can be achieved only by advancing the mathematical foundation of the cavitation processes. These processes are manifested in different ways, the most common ones and promising for control being bubble cavitation and supercavitation. The first exact classical solution should perhaps be credited to the well-known solution by Hermann von Helmholtz in 1868. The earliest distinguished studies of academic type on the theory of a cavitating flow with free boundaries and supercavitation were published in the book Jets, wakes and cavities followed by Theory of jets of ideal fluid. Widely used in these books was the well-developed theory of conformal mappings of functions of a complex variable, allowing one to derive a large number of exact solutions of plane problems. Another venue combining the existing exact solutions with approximated and heuristic models was explored in the work Hydrodynamics of Flows with Free Boundaries that refined the applied calculation techniques based on the principle of cavity expansion independence, theory of pulsations and stability of elongated axisymmetric cavities, etc. and in Dimensionality and similarity methods in the problems of the hydromechanics of vessels.

A natural continuation of these studies was recently presented in The Hydrodynamics of Cavitating Flows – an encyclopedic work encompassing all the best advances in this domain for the last three decades, and blending the classical methods of mathematical research with the modern capabilities of computer technologies. These include elaboration of nonlinear numerical methods of solving 3D cavitation problems, refinement of the known plane linear theories, development of asymptotic theories of axisymmetric and nearly axisymmetric flows, etc. As compared to the classical approaches, the new trend is characterized by expansion of the theory into the 3D flows. It also reflects a certain correlation with current works of an applied character on the hydrodynamics of supercavitating bodies.

Hydrodynamic cavitation can also improve some industrial processes. For instance, cavitated corn slurry shows higher yields in ethanol production compared to uncavitated corn slurry in dry milling facilities.

This is also used in the mineralization of bio-refractory compounds which otherwise would need extremely high temperature and pressure conditions since free radicals are generated in the process due to the dissociation of vapors trapped in the cavitating bubbles, which results in either the intensification of the chemical reaction or may even result in the propagation of certain reactions not possible under otherwise ambient conditions.

Acoustic cavitation and ultrasonic cavitation
Inertial cavitation can also occur in the presence of an acoustic field. Microscopic gas bubbles that are generally present in a liquid will be forced to oscillate due to an applied acoustic field. If the acoustic intensity is sufficiently high, the bubbles will first grow in size and then rapidly collapse. Hence, inertial cavitation can occur even if the rarefaction in the liquid is insufficient for a Rayleigh-like void to occur.

Ultrasonic cavitation inception will occur when the acceleration of the ultrasound source is enough to produce the needed pressure drop. This pressure drop depends on the value of the acceleration and the size of the affected volume by the pressure wave. The dimensionless number that predicts ultrasonic cavitation is the Garcia-Atance number. High power ultrasonic horns produce accelerations high enough to create a cavitating region that can be used for homogenization, dispersion, deagglomeration, erosion, cleaning, milling, emulsification, extraction, disintegration, and sonochemistry.

Aerodyamic cavitation
Although predominant in liquids, cavitation exists to an extent in gas as it has fluid dynamics at high speeds. For example a bullet with a flat tip moves faster underwater as it creates cavitation compared to a bullet with a sharp tip. An ideal shape for aerodynamic cavitation is a dune. It has such a form that provides minimal resistance to the wind. A surface with small dunes installed on aircraft and various high speed vehicles, the total friction against the air will decrease several times. The dune surface pushes the air upwards, underneath and behind the air pressure drops reducing friction. The dune may increase frontal resistance, but it will be compensated by a decrease in the total friction area, as it happens in an underwater bullet. As a result, the speed of the aircraft or vehicle will increase significantly.

Chemical engineering
In industry, cavitation is often used to 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 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.

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.

Biomedical
Cavitation plays an important role for the destruction of kidney stones in shock wave lithotripsy. Currently, tests are being conducted as to whether cavitation can be used to transfer large molecules into biological cells (sonoporation). Nitrogen cavitation is a method used in research to 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 and can be used to open the blood-brain barrier to increase uptake of neurological drugs in the brain.

Cavitation also plays a role in HIFU, a thermal non-invasive treatment methodology for cancer.

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.

Ultrasound sometimes is used to increase bone formation, for instance in post-surgical applications.

It has been suggested that the sound of "cracking" knuckles derives from the collapse of cavitation in the synovial fluid within the joint.

Cavitation can also form Ozone micro-nanobubbles which shows promise in dental applications.

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.

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.

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.

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.

Cavitation damage

Cavitation is usually an undesirable occurrence. In devices such as propellers and pumps, cavitation causes a great deal of noise, damage to components, vibrations, and a loss of efficiency. Noise caused by cavitation can be particularly undesirable in naval vessels where such noise may render them more easily detectable by passive sonar. Cavitation has also become a concern in the renewable energy sector as it may occur on the blade surface of tidal stream turbines.

When the cavitation bubbles collapse, they force energetic liquid into very small volumes, thereby creating spots of high temperature and emitting shock waves, the latter of which are a source of noise. The noise created by cavitation is a particular problem for military submarines, as it increases the chances of being detected by passive sonar.

Although the collapse of a small cavity is a relatively low-energy event, highly localized collapses can erode metals, such as steel, over time. The pitting caused by the collapse of cavities produces great wear on components and can dramatically shorten a propeller's or pump's lifetime.

After a surface is initially affected by cavitation, it tends to erode at an accelerating pace. The cavitation pits increase the turbulence of the fluid flow and create crevices that act as nucleation sites for additional cavitation bubbles. The pits also increase the components' surface area and leave behind residual stresses. This makes the surface more prone to stress corrosion.

Pumps and propellers
Major places where cavitation occurs are in pumps, on propellers, or at restrictions in a flowing liquid.

As an impeller's (in a pump) or propeller's (as in the case of a ship or submarine) blades move through a fluid, low-pressure areas are formed as the fluid accelerates around and moves past the blades. The faster the blade moves, the lower the pressure can become around it. As it reaches vapor pressure, the fluid vaporizes and forms small bubbles of gas. This is cavitation. When the bubbles collapse later, they typically cause very strong local shock waves in the fluid, which may be audible and may even damage the blades.

Cavitation in pumps may occur in two different forms:

Suction cavitation
Suction cavitation occurs when the pump suction is under a low-pressure/high-vacuum condition where the liquid turns into a vapor at the eye of the pump impeller. This vapor is carried over to the discharge side of the pump, where it no longer sees vacuum and is compressed back into a liquid by the discharge pressure. This imploding action occurs violently and attacks the face of the impeller. An impeller that has been operating under a suction cavitation condition can have large chunks of material removed from its face or very small bits of material removed, causing the impeller to look spongelike. Both cases will cause premature failure of the pump, often due to bearing failure. Suction cavitation is often identified by a sound like gravel or marbles in the pump casing.

Common causes of suction cavitation can include clogged filters, pipe blockage on the suction side, poor piping design, pump running too far right on the pump curve, or conditions not meeting NPSH (net positive suction head) requirements.

In automotive applications, a clogged filter in a hydraulic system (power steering, power brakes) can cause suction cavitation making a noise that rises and falls in synch with engine RPM. It is fairly often a high pitched whine, like set of nylon gears not quite meshing correctly.

Discharge cavitation
Discharge cavitation occurs when the pump discharge pressure is extremely high, normally occurring in a pump that is running at less than 10% of its best efficiency point. The high discharge pressure causes the majority of the fluid to circulate inside the pump instead of being allowed to flow out the discharge. As the liquid flows around the impeller, it must pass through the small clearance between the impeller and the pump housing at extremely high flow velocity. This flow velocity causes a vacuum to develop at the housing wall (similar to what occurs in a venturi), which turns the liquid into a vapor. A pump that has been operating under these conditions shows premature wear of the impeller vane tips and the pump housing. In addition, due to the high pressure conditions, premature failure of the pump's mechanical seal and bearings can be expected. Under extreme conditions, this can break the impeller shaft.

Discharge cavitation in joint fluid is thought to cause the popping sound produced by bone joint cracking, for example by deliberately cracking one's knuckles.

Cavitation solutions
Since all pumps require well-developed inlet flow to meet their potential, a pump may not perform or be as reliable as expected due to a faulty suction piping layout such as a close-coupled elbow on the inlet flange. When poorly developed flow enters the pump impeller, it strikes the vanes and is unable to follow the impeller passage. The liquid then separates from the vanes causing mechanical problems due to cavitation, vibration and performance problems due to turbulence and poor filling of the impeller. This results in premature seal, bearing and impeller failure, high maintenance costs, high power consumption, and less-than-specified head and/or flow.

To have a well-developed flow pattern, pump manufacturer's manuals recommend about (10 diameters?) of straight pipe run upstream of the pump inlet flange. Unfortunately, piping designers and plant personnel must contend with space and equipment layout constraints and usually cannot comply with this recommendation. Instead, it is common to use an elbow close-coupled to the pump suction which creates a poorly developed flow pattern at the pump suction.

With a double-suction pump tied to a close-coupled elbow, flow distribution to the impeller is poor and causes reliability and performance shortfalls. The elbow divides the flow unevenly with more channeled to the outside of the elbow. Consequently, one side of the double-suction impeller receives more flow at a higher flow velocity and pressure while the starved side receives a highly turbulent and potentially damaging flow. This degrades overall pump performance (delivered head, flow and power consumption) and causes axial imbalance which shortens seal, bearing and impeller life. To overcome cavitation: Increase suction pressure if possible. Decrease liquid temperature if possible. Throttle back on the discharge valve to decrease flow-rate. Vent gases off the pump casing.

Control valves
Cavitation can occur in control valves. If the actual pressure drop across the valve as defined by the upstream and downstream pressures in the system is greater than the sizing calculations allow, pressure drop flashing or cavitation may occur. The change from a liquid state to a vapor state results from the increase in flow velocity at or just downstream of the greatest flow restriction which is normally the valve port. To maintain a steady flow of liquid through a valve the flow velocity must be greatest at the vena contracta or the point where the cross sectional area is the smallest. This increase in flow velocity is accompanied by a substantial decrease in the fluid pressure which is partially recovered downstream as the area increases and flow velocity decreases. This pressure recovery is never completely to the level of the upstream pressure. If the pressure at the vena contracta drops below the vapor pressure of the fluid bubbles will form in the flow stream. If the pressure recovers after the valve to a pressure that is once again above the vapor pressure, then the vapor bubbles will collapse and cavitation will occur.

Spillways
When water flows over a dam spillway, the irregularities on the spillway surface will cause small areas of flow separation in a high-speed flow, and, in these regions, the pressure will be lowered. If the flow velocities are high enough the pressure may fall to below the local vapor pressure of the water and vapor bubbles will form. When these are carried downstream into a high pressure region the bubbles collapse giving rise to high pressures and possible cavitation damage.

Experimental investigations show that the damage on concrete chute and tunnel spillways can start at clear water flow velocities of between 12 and 15 m/s, and, up to flow velocities of 20 m/s, it may be possible to protect the surface by streamlining the boundaries, improving the surface finishes or using resistant materials.

When some air is present in the water the resulting mixture is compressible and this damps the high pressure caused by the bubble collapses. If the flow velocities near the spillway invert are sufficiently high, aerators (or aeration devices) must be introduced to prevent cavitation. Although these have been installed for some years, the mechanisms of air entrainment at the aerators and the slow movement of the air away from the spillway surface are still challenging.

The spillway aeration device design is based upon a small deflection of the spillway bed (or sidewall) such as a ramp and offset to deflect the high flow velocity flow away from the spillway surface. In the cavity formed below the nappe, a local subpressure beneath the nappe is produced by which air is sucked into the flow. The complete design includes the deflection device (ramp, offset) and the air supply system.

Engines
Some larger diesel engines suffer from cavitation due to high compression and undersized cylinder walls. Vibrations of the cylinder wall induce alternating low and high pressure in the coolant against the cylinder wall. The result is pitting of the cylinder wall, which will eventually let cooling fluid leak into the cylinder and combustion gases to leak into the coolant.

It is possible to prevent this from happening with the use of chemical additives in the cooling fluid that form a protective layer on the cylinder wall. This layer will be exposed to the same cavitation, but rebuilds itself. Additionally a regulated overpressure in the cooling system (regulated and maintained by the coolant filler cap spring pressure) prevents the forming of cavitation.

From about the 1980s, new designs of smaller gasoline engines also displayed cavitation phenomena. One answer to the need for smaller and lighter engines was a smaller coolant volume and a correspondingly higher coolant flow velocity. This gave rise to rapid changes in flow velocity and therefore rapid changes of static pressure in areas of high heat transfer. Where resulting vapor bubbles collapsed against a surface, they had the effect of first disrupting protective oxide layers (of cast aluminium materials) and then repeatedly damaging the newly formed surface, preventing the action of some types of corrosion inhibitor (such as silicate based inhibitors). A final problem was the effect that increased material temperature had on the relative electrochemical reactivity of the base metal and its alloying constituents. The result was deep pits that could form and penetrate the engine head in a matter of hours when the engine was running at high load and high speed. These effects could largely be avoided by the use of organic corrosion inhibitors or (preferably) by designing the engine head in such a way as to avoid certain cavitation inducing conditions.

Geology
Some hypotheses relating to diamond formation posit a possible role for cavitation—namely cavitation in the kimberlite pipes providing the extreme pressure needed to change pure carbon into the rare allotrope that is diamond. The loudest three sounds ever recorded, during the 1883 eruption of Krakatoa, are now understood as the bursts of three huge cavitation bubbles, each larger than the last, formed in the volcano's throat. Rising magma, filled with dissolved gasses and under immense pressure, encountered a different magma that compressed easily, allowing bubbles to grow and combine.

Vascular plants
Cavitation can occur in the xylem of vascular plants. The sap vaporizes locally so that either the vessel elements or tracheids are filled with water vapor. Plants are able to repair cavitated xylem in a number of ways. For plants less than 50 cm tall, root pressure can be sufficient to redissolve the vapor. Larger plants direct solutes into the xylem via ray cells, or in tracheids, via osmosis through bordered pits. Solutes attract water, the pressure rises and vapor can redissolve. In some trees, the sound of the cavitation is audible, particularly in summer, when the rate of evapotranspiration is highest. Some deciduous trees have to shed leaves in the autumn partly because cavitation increases as temperatures decrease.

Spore dispersal in plants
Cavitation plays a role in the spore dispersal mechanisms of certain plants. In ferns, for example, the fern sporangium acts as a catapult that launches spores into the air. The charging phase of the catapult is driven by water evaporation from the annulus cells, which triggers a pressure decrease. When the compressive pressure reaches approximately 9MPa, cavitation occurs. This rapid event triggers spore dispersal due to the elastic energy released by the annulus structure. The initial spore acceleration is extremely large – up to 10$5$ times the gravitational acceleration.

Marine life
Just as cavitation bubbles form on a fast-spinning boat propeller, they may also form on the tails and fins of aquatic animals. This primarily occurs near the surface of the ocean, where the ambient water pressure is low.

Cavitation may limit the maximum swimming speed of powerful swimming animals like dolphins and tuna. Dolphins may have to restrict their speed because collapsing cavitation bubbles on their tail are painful. Tuna have bony fins without nerve endings and do not feel pain from cavitation. They are slowed down when cavitation bubbles create a vapor film around their fins. Lesions have been found on tuna that are consistent with cavitation damage.

Some sea animals have found ways to use cavitation to their advantage when hunting prey. The pistol shrimp snaps a specialized claw to create cavitation, which can kill small fish. The mantis shrimp (of the smasher variety) uses cavitation as well in order to stun, smash open, or kill the shellfish that it feasts upon.

Thresher sharks use 'tail slaps' to debilitate their small fish prey and cavitation bubbles have been seen rising from the apex of the tail arc.

Coastal erosion
In the last half-decade, coastal erosion in the form of inertial cavitation has been generally accepted. Bubbles in an incoming wave are forced into cracks in the cliff being eroded. Varying pressure decompresses some vapor pockets which subsequently implode. The resulting pressure peaks can blast apart fractions of the rock.

History
As early as 1754, the Swiss mathematician Leonhard Euler (1707–1783) speculated about the possibility of cavitation. In 1859, the English mathematician William Henry Besant (1828–1917) published a solution to the problem of the dynamics of the collapse of a spherical cavity in a fluid, which had been presented by the Anglo-Irish mathematician George Stokes (1819–1903) as one of the Cambridge [University] Senate-house problems and riders for the year 1847. In 1894, Irish fluid dynamicist Osborne Reynolds (1842–1912) studied the formation and collapse of vapor bubbles in boiling liquids and in constricted tubes.

The term cavitation first appeared in 1895 in a paper by John Isaac Thornycroft (1843–1928) and Sydney Walker Barnaby (1855–1925)—son of Sir Nathaniel Barnaby (1829 – 1915), who had been Chief Constructor of the Royal Navy—to whom it had been suggested by the British engineer Robert Edmund Froude (1846–1924), third son of the English hydrodynamicist William Froude (1810–1879). Early experimental studies of cavitation were conducted in 1894-5 by Thornycroft and Barnaby and by the Anglo-Irish engineer Charles Algernon Parsons (1854-1931), who constructed a stroboscopic apparatus to study the phenomenon. Thornycroft and Barnaby were the first researchers to observe cavitation on the back sides of propeller blades.

In 1917, the British physicist Lord Rayleigh (1842–1919) extended Besant's work, publishing a mathematical model of cavitation in an incompressible fluid (ignoring surface tension and viscosity), in which he also determined the pressure in the fluid. The mathematical models of cavitation which were developed by British engineer Stanley Smith Cook (1875–1952) and by Lord Rayleigh revealed that collapsing bubbles of vapor could generate very high pressures, which were capable of causing the damage that had been observed on ships' propellers. Experimental evidence of cavitation causing such high pressures was initially collected in 1952 by Mark Harrison (a fluid dynamicist and acoustician at the U.S. Navy's David Taylor Model Basin at Carderock, Maryland, USA) who used acoustic methods and in 1956 by Wernfried Güth (a physicist and acoustician of Göttigen University, Germany) who used optical Schlieren photography.

In 1944, Soviet scientists Mark Iosifovich Kornfeld (1908–1993) and L. Suvorov of the Leningrad Physico-Technical Institute (now: the Ioffe Physical-Technical Institute of the Russian Academy of Sciences, St. Petersburg, Russia) proposed that during cavitation, bubbles in the vicinity of a solid surface do not collapse symmetrically; instead, a dimple forms on the bubble at a point opposite the solid surface and this dimple evolves into a jet of liquid. This jet of liquid damages the solid surface. This hypothesis was supported in 1951 by theoretical studies by Maurice Rattray Jr., a doctoral student at the California Institute of Technology. Kornfeld and Suvorov's hypothesis was confirmed experimentally in 1961 by Charles F. Naudé and Albert T. Ellis, fluid dynamicists at the California Institute of Technology.

A series of experimental investigations of the propagation of strong shock wave (SW) in a liquid with gas bubbles, which made it possible to establish the basic laws governing the process, the mechanism for the transformation of the energy of the SW, attenuation of the SW, and the formation of the structure, and experiments on the analysis of the attenuation of waves in bubble screens with different acoustic properties were begun by pioneer works of Soviet scientist prof.V.F. Minin at the Institute of Hydrodynamics (Novosibirsk, Russia) in 1957–1960, who examined also the first convenient model of a screen - a sequence of alternating flat one-dimensional liquid and gas layers. In an experimental investigations of the dynamics of the form of pulsating gaseous cavities and interaction of SW with bubble clouds in 1957–1960 V.F. Minin discovered that under the action of SW a bubble collapses asymmetrically with the formation of a cumulative jet, which forms in the process of collapse and causes fragmentation of the bubble.

title: Cavitation


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Cyprinodontiformes

Cyprinodontiformes is an order of ray-finned fish, comprising mostly small, freshwater fish. Many popular aquarium fish, such as killifish and live-bearers, are included. They are closely related to the Atheriniformes and are occasionally included with them. A colloquial term for the order as a whole is toothcarps, though they are not actually close relatives of the true carps – the latter belong to the superorder Ostariophysi, while the toothcarps are Acanthopterygii.

The families of Cyprinodontiformes can be informally divided into three groups based on reproductive strategy: viviparous and ovoviviparous (all species give live birth), and oviparous (all species are egg-laying). The live-bearing groups differ in whether the young are carried to term within (ovoviviparous) or without (viviparous) an enclosing eggshell. Phylogenetically however, one of the two suborders – the Aplocheiloidei – contains oviparous species exclusively, as do two of the four superfamilies of the other suborder (the Cyprinodontoidea and Valencioidea of the Cyprinodontoidei). Vivipary and ovovivipary have evolved independently from oviparous ancestors, the latter possibly twice.

Description
Some members of this order are notable for inhabiting extreme environments, such as saline or very warm waters, heavily polluted waters, rain water pools devoid of minerals and made acidic by decaying vegetation, or isolated situations where no other types of fish occur.

They are typically carnivores, and often live near the surface, where the oxygen-rich water compensates for environmental disadvantages. Scheel (1968) observed the gut contents were invariably ants, others have reported insects, worms and aquatic crustaceans. Aquarium specimens are invariably seen eating protozoans from the water column and the surfaces of leaves, however these are not apparent as stomach contents. Many members of the family Cyprinodontidae (the pupfishes) eat plant material as well and some have adapted to a diet very high in algae to the point where one, the American Flag Fish, is a renowned algae eater in the aquarium, in spite of belonging to an order of fishes that do not generally consume any plant material. In addition, killifish derive some of the carotenoids and other chemicals required to make their body pigments from pollen grains on the surface of and in the gut of insects they eat from the surface of the water; this can be simulated in culture by the use of special color enhancing foods that contain these compounds.

Although the Cyprinodontiformes are a diverse group, most species contained within are small to medium-sized fish, with small mouths, large eyes, a single dorsal fin, and a rounded caudal fin. The largest species is the cuatro ojos (Anableps dowei), which measures 34 cm in length, while the smallest, the least killifish (Heterandria formosa), is just 8 mm long as an adult.

Systematics
CYPRINODONTIFORMES
 * Suborder Aplocheiloidei (all oviparous)
 * Family Aplocheilidae _ Asian killifishes
 * Family Nothobranchiidae _ African killifishes
 * Family Rivulidae _ New World killifishes
 * Suborder Cyprinodontoidei
 * Superfamily Funduloidea
 * Family Profundulidae – Central American killifishes (oviparous)
 * Family Goodeidae – splitfins (largely viviparous)
 * Family Fundulidae – topminnows and North American killifishes (oviparous)
 * Superfamily Valencioidea (oviparous)
 * Family Valenciidae – Mediterranean killifishes
 * Superfamily Cyprinodontoidea (oviparous)
 * Family Cyprinodontidae – pupfishes
 * Family Aphaniidae _ Oriental killifishes
 * Superfamily Poecilioidea
 * Family Anablepidae – four-eyed fishes and relatives (largely ovoviviparous)
 * Family Poeciliidae – livebearers and relatives (some oviparous, some ovoviviparous)

The family Aplocheilidae has been expanded by some authorities to include all the killifishes with three subfamilies, Aplocheilinae, Cynolebiinae and Nothobranchiinae, but this is not the classification adopted in the 5th Edition of Fishes of the World.

title: Cyprinodontiformes


text:
Talk:Conditioning

well you are all wrong it is math

Needed
Conditioning (statistical tests) Tedtoal (talk) 21:01, 27 October 2011 (UTC)
 * You should start a page and equest help from other editors.Beefcake6412 (talk) 21:02, 27 October 2011 (UTC)

Needed
Conditioning of Environment pages. There's a species example here: http://www.springerprotocols.com/Abstract/doi/10.1007/978-1-59745-413-1_16

BioImages2000 (talk) 11:20, 14 December 2012 (UTC)

title: Talk:Conditioning