Crossbow

A good example of a shoulder-cock crossbow is the FX-II crossbow. The primary benefit of this concept is the fact that it uses no water directly. The average draw force for the shoulder-cock crossbow is 100 lbf (400 N), which is low compared to other crossbows. Supercritical carbon dioxide has previously been used in dry cleaning. Using a shoulder-cock, a good crossbowman could reload in under 7 seconds. The grease is filtered from the carbon dioxide and removed from the system. The shoulder-cock is extremely easy to use and has a fast loading time. It also demonstrates the physical properties of a liquid, hence the solvent effectiveness, and a gas, which fills its container and thus does not require as much mechanical agitation.

One of the newest developments in crossbow technology is the use of the shoulder-cock. Pressurized carbon dioxide behaves like a nonpolar solvent, which can effectively remove grease. They are made of the same composite materials as modern bows. Its primary feature was the use of supercritical carbon dioxide in place of water in closed-loop operation. Modern crossbows are still used for target shooting and in some places for hunting. A team of students from the University of New South Wales in Sydney, Australia won top honors in the 2004 Electrolux Design Laboratory competition for their Rockpool waterless dishwasher design. Early guns had slower rates of fire and much worse accuracy than contemporary crossbows. [1] The study does not address costs associated with the manufacture and disposal of dishwashers.

Crossbows were eventually replaced in warfare by gunpowder weapons. At least one privately funded, non-peer-reviewed study concludes that automatic dishwashers use less water than even the most efficient hand-washers, while relative energy use depends on hand-washing technique. Given the great accuracy of the crossbow, it filled many duties that sniper rifles have today. Comparing the efficiency of automatic dishwashers and hand-washing of dishes is difficult because hand-washing techniques vary drastically by individual. However, their effectiveness made them an "evil" no one could afford to be without, often in the form of hired foreign mercenaries. One of the most well know brands of commercial dishwasher is Hobart.[www.hobartcorp.com]. The crossbow was seen as unchivalrous and as a threat to social order, since a peasant could kill a noble anonymously; crossbow mercenaries were usually killed immediately on capture, unlike others who might have been ransomed or set free. There are many types of commercial dishwashers including undercounter, single tank, conveyor, flight type, and carousel machines.

Pope Urban II banned the use of crossbow against Christians in 1097, and the Second Lateran Council did the same for arbalests in 1139. Hot water sanitizing requires a rinse temperature of at least 180 °F (80 °C). Due to the long time required to reload a crossbow, users would sometimes make use of a pavise. NSF (http://www.nsf.org/business/food_equipment/standards.asp?program=FoodEqu) sets the standards for wash and rinse time along with proper water temperature for chemical or hot water sanitizing methods. Moreover, crossbows could be kept cocked and ready to shoot for some time with little effort, allowing crossbowmen to aim better and to "cover" a target area, while archers could not keep their powerful bows pulled for long periods of time. Commercial machines are capable of washing a rack of dishes in just a few minutes or less using a wash water temp of usually 120 to 140 °F (50 to 60 °C) for a low temperature sanitizing machine or 150 minimum wash temp for a hot water sanitizing machine. In the later years of the crossbow it had enough kinetic energy to penetrate the armor of a knight with ease: some reached a draw force of nearly 350 lbf (1600 N), compared to the 60-180lbf (300-900 N) draw force for a longbow. Much larger heavy-duty dishwashers with a high output are available for use in catering and commerical establishments where a large number of dishes are to be washed and sanitized.

The use of winches allowed soldiers to use and fire weapons with a draw force far in excess of what they could have handled with a bow. The other method is a chemical sanitisation method, that many commercial low temperature machines use, using chlorine injected in the final rinse water. An expertly handled longbow had greater range, better accuracy (the "arbalest" or siege crossbow being the exception here), and a much faster rate of fire than an average crossbow, but the value of the crossbow came in its simplicity: it could be used effectively after a week of training, while a comparable single-shot skill with a longbow could take years. One is to use hot water sanitising, using final rinse water at a temperature of at least 83 °C (180 °F). They supplanted bows in many European armies for a number of reasons. Commercial dishwashers can use one of two types of sanitisation methods. Crossbows were actively being used in European warfare from 800 to 1500 A.D. Dishwashers (even commercial ones used in restaurants) do not do this.

. Domestic dishwashers do not sterilise the utensils, as proper sterilisation requires autoclaving at 121 °C with pressurised wet steam for at least 15 minutes. Some Belgian designs were as polished as those of modern Olympic rifles. In addition, the lead in the crystal glass can be converted into a soluble form, which is not good for the health of subsequent users. Makers of crossbows (arbalistmeisters) were making quite beautiful crossbow stocks by 1600. Lead crystal should not be cleaned in a dishwasher as the corrosive effect of dishwasher detergent is high on such types of glass - that is, it will quickly go 'cloudy'. By 1650, the cross bow looked like it had a rifle stock, and was used in a similar way (what you see on a rifle has probably already been done on a crossbow). This may be caused by any or all of the below processes, only one of which is reversible:.

About 1400 the use of the crossbow changed, with the butt end of the stock being placed on the shoulder for accuracy. Glassware that is washed by dishwashing machines often develops a white haze on the surface over time. A crossbow prod was made out of spring steel, steel prods being very common by the early 1500s as their performance was more uniform, except in very cold weather. Inexpensive powders sometimes actually contain sand, which can be verified by dissolving the powder in boiling water and then passing the solution through a coffee filter; these detergents should be avoided to prevent wear of the dishes and the dishwasher. In the later 1400s, steel manufacturing advanced significantly, and was more commonly used in spring production. Intuition suggests that a powder will provide a better scrubbing action due to a soft media sandblasting effect, though liquid detergents have marketed themselves as premium products. It was not uncommon for six months up to a year to be spent in ensuring a bow was dried properly. Dishwasher detergents are strongly alkaline (basic).

The strongest glues naturally took longer to dry. it may also contain:. Since composite prods involved gluing material together which would have to withstand a great deal of stress, a slow drying time was essential. Dishwashing detergent contains:. It is the high launch force of a crossbow that made it a formidable weapon in warfare. Sound dampening is the primary factor that determines the cost of a standard built-in dishwasher. Since the draw force can be much more than a soldier might be able to pull, these crossbows generally include a winch device to cock them. Thus, a QuietPartner 1 or QuietGuard 2 dishwasher, despite the "Quiet" designation, may not actually be quiet at all.

The draw force is the tension that the string is under when the bow is engaged. Higher numbers usually indicate higher sound dampening and thus less noise output. Composite prods were made of horn, sinew and wood, and produced much larger draw forces. QuietGuard (Kenmore), QuietPartner (Whirlpool), Whisper Package (Maytag), followed by a number. The advantage of a simple wooden prod is that the bow as a whole was lighter in weight, easier to span (even by hand), and quicker to discharge. Manufacturers generally use their own nomenclature with sound dampening, i.e. The prod of a crossbow was made of wood or composite materials until the middle of the 15th century. Undampened, low-end dishwashers generally output noise levels of anywhere from 65-70 decibels.

Roman bows tended to be ornate and well engineered, yet western European bowstocks that were produced 600 years later appeared to be nothing more than rough hewn slabs of wood. Using blankets, panels, and sound-absorbing materials in various configurations, dishwashers can achieve sound dampening levels down to 44 decibels or so. One of the most distinctive Chinese inventions on crossbows was the repeating crossbow (Chu-ko-nu), invented in 2nd Century AD which was used as late as China-Japan war of 1894-1895 by Manchurian troops. However, pressure switches (some dishwashers use a pressure switch and flow meter) are not required in most microprocessor controlled dishwashers as they use the motor and sometimes a rotational position sensor to sense the resistance of water, when it senses there is no cavitation it knows it has the optimal amount of water. Some linguistic evidence also seems to indicate a Southeast Asian origin ^[3]. In such dishwashers the electromechanical rotary switch often used to control the washing cycle is replaced by a microprocessor but most sensors and valves are still required to be present. Crossbows have been found among the soldiers of the Terracotta Army in the tomb of emperor Qin Shi Huang (260-210 BCE) ^[2]. This can save water and energy if the user runs a partial load.

By the 200s BC, the crossbow (nǔ, 弩) was well developed and quite widely used in China^[1]. Many newer dishwashers feature microprocessor-controlled, sensor-assisted wash cycles that adjust the wash duration to the quantity of dirty dishes (sensed by changes in water temperature) or the amount of dirt in the rinse water (sensed chemically/optically). This prevents them from snagging on the crossbow nut as they are shot. Pre-rinsing under a running tap beforehand simply wastes water. They also typically only have two fletches per bolt instead of three commonly seen on arrows. Pre-rinsing is not necessary even without integrated waste disposal units - all that is required is for the larger items of food waste to be removed before placing in the dishwasher. Crossbow bolts are lighter than arrows, but must be sealed with a varnish to ensure their consistent weight. One manufacturer that is known for omitting hard food disposals is Bosch, a German brand; however, Bosch does so in order to reduce noise.

Leonardo da Vinci designed many complicated triggers for crossbows, ultimately producing a "hair trigger" that could be shot with very little finger strength. Mid-to-higher end North American dishwashers often come with hard food disposal units, which behave like miniature garbage (waste) disposal units that eliminate large pieces of food waste from the wash water. Triggers are known to have been used on crossbows from the early 1400s. Older models used a baked enamel on steel and are prone to chipping and erosion; chips in the baked enamel finish must be cleaned of all dirt and corrosion then patched with a special compound or even a good quality two-part epoxy. The crossbow also includes a trigger, which was later incorporated into rifles, muskets and other firearms. They also come at a price premium. In wet, twisted mulberry root was occasionally used. Stainless steel tubs resist hard water, provide better sound dampening, and preserve heat to dry dishes faster.

Even cotton was tried with some success. The inside of a dishwasher, called the tub, can be composed of plastic or stainless steel. Patternson, whipcord was very common; however linen, hemp, and sinew were used as well. Dishwashers may come in standard or tall tub designs; standard tub dishwashers have a service kickplate beneath the dishwasher door that allows for simpler maintenance and installation, but tall tub dishwashers have approximately 20% more capacity and better sound dampening from having a continuous front door. F. Portable dishwashers exist in 45 and 60 cm (Europe) 18 and 24 inch (US) widths, with castors and attached countertops. According to W. Dishwashers that are installed into standard kitchen cabinets have a standard width and depth of 60 cm (Europe) or 24 inches (US), and most dishwashers must be installed into a hole a mininum of 86 cm (Europe) or 34 inches (US) tall.

The strings for a crossbow are typically made of strong fibers that would not tend to fray. Dishes or plates of irregular sizes may not fit properly in a dishwasher's cleaning compartment, so it is advisable to check for compatibility before buying a dishwasher. The crossbow shelf is a flat section above the stock with a straight groove for the bolt to rest upon and travel along as it is shot. The capacity of a dishwasher according to international standards is measured in standard place settings. The draw weight of a modern crossbow can be up to 300lbs. Adoption was greatest at first in commercial environments, but by the 1970s dishwashers had become commonplace in domestic situations. This makes crossbows inefficient at storing energy, which is why they must have very heavy draw weights. Models installed with permanent plumbing arrived in 1920s, and electric drying elements were added in 1940.

The prod is very short compared to bows, thus resulting in a short draw length. She never washed dishes herself and only invented the dishwasher as her servants were chipping her fine china. Much as a horse's bridle, it tends to loosen over time, and must be carefully respliced when appropriate. Cochrane was quite wealthy and was the granddaughter of John Fitch, the inventor of the steam boat. This cording is called the bridle of the crossbow. Modern dishwashers are descended from the 1886 invention of Josephine Cochrane, also hand-powered, which she unveiled at the 1893 Chicago World's Fair. The prod (also called lath in England) is attached to the stock with hemp rope, linen, whipcord, or other strong cording. The first reports of a mechanical dishwashing device are of an 1850 patent by Joel Houghton of a hand-powered device.

The central European bows were rather exotic as they were constructed of inlays as well as specialized woods. Some dishwashers also contain a heating element to achieve fast drying of the dishes. The prod ("bow") and stock of a crossbow were made of good hardwood, such as oak or hard maple. The dishwasher therefore is mainly a device for spraying water on the dishes - first detergent-added water for cleaning purposes, then clean water (though sometimes with a rinsing aid added) to remove the detergent residue. Typically, the nut is at the end of the shelf (also called the bolt rest). Unlike manual dishwashing, which relies largely on mechanical action to remove soiling, mechanical dishwashers use the circulation of quite hot (55-65 degrees Celsius or 130-150 degrees Fahrenheit) water (usually, but not always heated or brought up to temperature by an element) and very strong detergents (most far too alkaline for habitual exposure to the skin) to achieve its cleaning effect. A crossbow contains a string which is held in place by a nut when the bolt is loaded and the cross bow is engaged (referred to as at full draw). .

This consistent performance was part of what made the crossbow historically a significant force in warfare. They are found in restaurants and also in many kitchens of homes. Crossbow bolts must be made to have consistent weights as the mechanical process of engaging a bolt forces a more uniform process than that of using a bow and arrow. A dishwasher is a mechanical device for cleaning food utensils for preparation, keeping, serving and eating and drinking. The stock and trigger of hand-held firearms may have been copied from crossbows. The latter usage is discussed in this article. These bolts are typically called quarrels, and do not depend upon lift as arrows do. The term dishwasher can represent either a person who washes (cleans) dishes (a term commonly used in the food service industry) or a machine that performs a similar function.

A crossbow consists of a prod (similar in appearance to a bow) mounted on a stock similar to a rifle stock, which has a mechanism to wind and shoot its bolts. washing dishes by hand. . Study of dishwashers vs. invented in China, the crossbow played a significant role in European medieval warfare and is still used today. http://archives.tcm.ie/businesspost/2005/01/30/story1860.asp. A crossbow is a weapon that fires projectiles called crossbow bolts or quarrels. http://www.yale.edu/ynhti/curriculum/units/1997/7/97.07.05.x.html.

http://www.scienceblog.com/community/older/2003/F/20033788.html. http://www.newi.ac.uk/buckleyc/materials.htm#Glass. http://www.ccspa.org/conseducation/SDAC_autodish.html. http://www2.whirlpool.com/html/homelife/cookin/cookdw5.htm.

Physical abrasion
- Glassware placed such that it is physically touching can abrade and produce a milky surface. Sodium carbonate solution is alkaline and leaches out SiO₂ from the glass. Sodium bicarbonate decomposes to sodium carbonate (by losing CO₂) in the hot final rinse. The water softener replaces calcium with sodium.

bicarbonate) hardness and the water softener is used. Etching occurs in the final (hot) rinse if the water supply has a high temporary (i.e. Silicate filming/etching/accelerated crack corrosion
- Silicate in the detergent protects glass from etching but only during the wash cycle - it is rinsed away after the wash. The resin may have stopped working because it has be poisoned by iron or manganese salts in the supply water.

The dishwasher should either be recharged with salt, adjusted appropriately for the hardness of the supply water - or possibly this is a symptom of failure of the ion exchange resin in the water softener (which is one of the more expensive components). It can be removed by cleaning with vinegar or lemon juice, or a proprietary limescale removal agent. Limescale deposit
- If the dishwasher has run out of the salt that recharges the ion exchange resin that softens the water, and the water supply is 'hard', limescale deposits can appear on all items, but are especially visible on glassware. Sand (inexpensive powdered detergents).

Gelling agents (in liquid/gel based detergents). Starches (in tablet based detergents). Anti-caking agents (in granular detergent). Perfumes.

Additives to slow down the removal of glaze & patterns from glazed ceramics. Anti-foaming agents
- Used as foam decreases the effectiveness of the washing action. Anti-corrosion agents
- Often sodium silicate, prevents corrosion of dishwasher components. Enzymes
- Breaks up and solublises protein-based food deposits, and possibly oil, lipid and fat deposits.

Non-ionic surfactants
- Lowers the surface tension of the water, emulsifies oil, lipid and fat food deposits, prevents droplet spotting on drying. Oxygen-based bleaching agents
- Breaks up and bleaches organic deposits. Phosphates
- Solublises calcium and magnesium ions to prevent 'hard-water' type limescale deposits. Whirlpool.

Manufactured by either Whirlpool Corporation or Frigidaire. Kenmore. Frigidaire. Whirlpool, featuring plastic tubs, and relocatable in-door utensil racks.

Maytag, featuring plastic and stainless steel tubs, tiered racks, and numerous additional side racks. Manufactured by Whirlpool Corporation. Kenmore, featuring plastic tubs and hard food disposals. Manufactured by AMAG.

Low water and energy consumtion. ASKO, featuring stainless steel tubs and self-cleaning filtration. Manufactured by Maytag Corporation. Jenn-Air.

Fisher and Paykel. GE Profile. GE Monogram. Manufactured by Whirlpool Corporation.

Kenmore Elite, featuring adjustable upper racks, stainless steel tubs, and TurboZone (a bank of jets in the back of the dishwasher designed especially for potscrubbing). Bosch, featuring stainless steel tubs and self-cleaning filtration. Manufactured by Whirlpool Corporation. KitchenAid, featuring custom panel kits, hard food disposals, and stainless steel tubs.