Evaporative cooling - Evaporative cooling Evaporative cooling is a system in which latent heat of evaporation is used to carry heat away from an object to cool it. The latent heat contains a considerable amount of energy, and carries away more heat than if the same temperature liquid was simply removed physically. The simplest example would be sweat, which the body secretes in order to cool itself. The amount of heat transfer depends on the evaporation rate, which in turn depends on the humidity of the air and its temperature, which is why you sweat more on hot, humid days. Evaporative cooling was in vogue for aircraft designs for some time in the late 1930's. In this case the system was used in order to reduce, or eliminate completely,.
Green roof - that is from some angles indistinguishable from a natural one. Green roofs are used to: Provide amenity space for building users - in effect replacing a yard or patio Reduce heating (by adding mass and thermal resistance value) and cooling (by evaporative cooling) loads on a building - especially if it is glassed in so as to act as a terrarium and passive solar heat reservoir Reduce the urban heat island effect Increase roof life span Reduce storm water run off - see water-wise gardening Filter pollutants and CO2 out of the air - see breathing wall Provide locally grown food - in which case it is known as a roof garden Increase wildlife habitat in built up areas - see urban wilderness A green roof is often a key component.
Electricity generation - power the generators. Tidal harnesses use the force of the moon on bodies of water to spin a turbine. Wind generators use wind to turn turbines that are hooked up to a generator. Pumped storage hydroelectricity is used to level demands on the power grid. Co-generation plants combine the generation of electricity and heat using solar power, fossil fuels, syngas, biomass, or biogas as a fuel source. These plants can achieve efficiencies as high as 80%, but many of these plants being built today only expect to achieve stated maximum 55% efficiency. Heated steam turns a turbine, and then excess heat is distributed for space heating in buildings, industrial processes or green house heating. Whole communities can benefit form heat distributed through a district heating scheme Fuel cells produce electricity using.
Emu - it rains in summer, mating starts just before "the wet", and emus are reliably reported to delay mating if the season is late. The mechanism for this remains unknown.) Despite the determined attention of the male, emu eggs are heavily predated, particularly by goannas, but it is estimated that four out of five chicks that hatch successfully survive to adulthood. Newly hatched chicks are active and can leave the nest within a few days. They stand about 25 cm tall, and have distinctive brown and cream stripes for camouflage, which fade after three months or so. The male stays with the growing chicks for at least six months, defending them and teaching them how to find food. A male emu will often adopt any strange chick found wandering, so long as.
Ethylene glycol - its precursor ethylene oxide became cheaply available. When first introduced it created a minor revolution in aircraft design because when used in place of water as a radiator coolant, its higher boiling point allowed for smaller radiators operating at higher temperatures. Prior to the widespead availability of ethylene glycol, many aircraft manufacturers tried to use evaporative cooling systems which used water at high pressure. Invariably these proved to be rather unreliable and easily damaged in combat because they took up large amounts of room on the plane, where they were easily hit by gunfire. Production Ethylene glycol is produced from ethylene, via the intermediate ethylene oxide. Ethylene oxide reacts with water to produce ethylene glycol according to the chemical equation C2H4O + H2O → HOCH2CH2OH This reaction can be catalyzed by.
3-quinuclidinyl benzilate - on the battlefield, terrorists may choose to disseminate BZ in forms that provide significant opportunities for ingestion and absorption through the skin. Following absorption, BZ is systemically distributed to most organs and tissues of the body. Its ability to reach synapses and neuromuscular and neuroglandular junctions throughout the body is responsible for its PNS effects, whereas its ability to cross the blood-brain barrier confers upon it the ability to cause CNS effects. Atropine and hyoscyamine both cross the placenta and can be found in small quantities in breast milk; whether this is also true for BZ is unclear. Metabolism of BZ would be expected to occur primarily in the liver, with elimination of unchanged agent and metabolites chiefly in the urine. TOXICITY The characteristic that makes BZ an incapacitating rather than.
Air conditioning - an appliance or mechanism designed to modify air temperature, generally cooling it down. It was invented by Willis Haviland Carrier (1876 - 1950) around 1902. Air conditioning units may also reduce the humidity of the air processed by the system. Since drier air aids evaporative cooling of people, this improves the comfort provided. From a mechanical engineering viewpoint, a modern air conditioner is a specialized form of a heat engine. It is designed for maximum efficiency when work is being applied to cool a living or storage volume by pumping heat from a low temperature heat source to a higher temperature heat sink. In electric units this is typically done by using an electric motor to drive a compressor. The compressor compresses a working fluid. During compression the working fluid is.
Autonomous building - used to replace an existing roof. Electricity Using a solar roof, solar cells can currently (2001) provide electric power. Solar roofs are far more cost-effective than retrofitted solar power. Most areas that lack sun have winds. In these areas, to generate its own power, a house would need a small wind turbine, five meters or less in diameter. On a thirty meter tower, it can provide enough power to supplement the solar power on cloudy days. Commercially-available wind-turbines use sealed, one-moving-part AC generators and passive self-feathering blades for years of operation without service. The largest advantage of wind-power is that larger wind turbines have a lower per-watt cost than solar cells, if there is wind. However location is critical, because some locations lack sufficient wind for an economical installation. In the.
Bose-Einstein condensate - impossible to know both a particle's velocity and a particle's position simultaneously with certainty. When a group of atoms is cooled to a low enough temperature, however, their velocities become very certain; they must be moving very slowly, or, stated more technically, they must have low quantum energy levels. This causes their positions to "smear out," effectively causing the individual atoms to overlap each other. In a Bose-Einstein condensate, the many overlapping atoms can be considered to be a single super-atom, with all of its constituent atoms sharing a single quantum state. A Bose-Einstein condensate was not actually created in a lab until June 5, 1995, when Eric Cornell and Carl Wieman used a combination of laser cooling (a technique the invention of which won Steven Chu, Claude Cohen-Tannoudji, and William.
Thermoregulation - extremes and metabolic reactions occur best at certain temperatures; both endotherms, which control the build-up of heat from aerobic respiration (homeotherms) and ectotherms (poikilotherms) can thermoregulate but only the endotherms (birds and mammals) can maintain a stable body temperature by using their nervous, endocrine, respiratory and circulatory systems. Heat gains and losses in animals conduction - heat escapes from your body when you sit on a cold rock. convection - cooler air currents remove heat from the surface of your skin. evaporation - evaporative cooling occurs when water (often from perspiration) leaves the skin surface as a gas, lowering the body temperature by cooling blood vessels in the dermis. radiation - e.g. acquisition of heat from solar radiation (e.g. snakes "sunning" on a cold day). Types of thermoregulation There are two.
Red oil - can include diluent (kerosene-like liquid used to dilute TBP) and/or aqueous phase metal nitrates. Controls for prevention or mitigation of a red oil explosion are generally categorized as controls for temperature, pressure, mass, and concentration. Maintaining a temperature of less than 130°C is generally accepted as a means to prevent red oil explosions. Sufficient venting serves to keep pressure from destroying the process vessel, while also providing the means for evaporative cooling to keep red oil from reaching the runaway temperature. Mass controls utilize decanters or hydrocyclones to remove organics from feedstreams entering process equipment capable of producing red oil. Limiting the total available TBP is another mass control that mitigates the consequence of a red oil explosion by limiting its maximum available explosive energy. Finally, concentration control can be utilized.
Merlin engine - developed into a 1,500hp class engine of its own, itself a development of the Buzzard, a scaled up Kestrel. However this plan left a large gap between 700hp and 1,500hp. To fill the gap work was started on a new 1,100hp class design as the PV-12 – PV for "private venture" as they received no money for work on the project. It first flew on the front of a Hawker Hart biplane in 1935, using the new evaporative cooling system then in vogue. The cooling system proved to be somewhat suspect, and when supplies of ethylene glycol (Prestone) from the US became available, the engine was switched to this system instead. In 1936 the Air Ministry called for new fighter aircraft with airspeeds that would eventually have to be over 300mph..
Legionnaires' disease - possibility of legionellosis in order to obtain the right tests. Several types of tests are available. The most useful tests detect the bacteria in sputum, find Legionella antigens in urine samples, or compare antibody levels to Legionella in two blood samples obtained 3 to 6 weeks apart. Who gets legionellosis? People of any age may get Legionnaires' diasease, but the illness most often affects middle-aged and older persons, particularly those who smoke cigarettes or have chronic lung disease. Also at increased risk are persons whose immune system is suppressed by diseases such as cancer, kidney failure requiring dialysis, diabetes, or AIDS. Those that take drugs that suppress the immune system are also at higher risk. Pontiac fever most commonly occurs in persons who are otherwise healthy. Treatment of legionellosis Erythromycin is.
Global cooling - Global cooling Global cooling is (or perhaps more appropriately was) a concern that the Earth may be ending its current warm period, the climate will cool, and perhaps even begin the glaciation of an ice age. There are two possible physical mechanisms that were most frequently advanced to cause cooling: aerosols and orbital forcing. Table of contents showTocToggle("show","hide") 1 Aerosols 2 Orbital forcing 3 1970 Cooling Peak Piqued Interest 4 1970 SCEP report 5 1971 Paper on Warming and Cooling Factors 6 1975 National Academy of Sciences report 7 National Science Board 8 1975 Newsweek article 9 1979 WMO conference 10 Climate cooling catastrophes 11 Climate science has improved 12 The present level of knowledge 13.
Cooling pond - Cooling pond Generally, a cooling pond is regarded as a man-made body of water primarily formed for the purpose of providing cooling water for a nearby power plant. Most such lakes have secondary outdoor recreational purposes that include fishing, swimming, boating, camping and picnicing. This article is a stub. You can help Wikipedia by fixing it..
Thermoelectric cooling - Thermoelectric cooling Thermoelectric cooling uses the Peltier effect to create a heat flux between the junction of two different types of materials. This article is a stub. You can help Wikipedia by fixing it..
Katabatic wind - instance the Mistral in the Mediterranean, the Bura(or Bora) in the Adriatic or the Oroshi in Japan). In more recent times, however, the term katabatic wind usually refers to the cold variant. The cold form of katabatic wind originates in a cooling, either radiatively or through vertical motion, of air at the top of the mountain, glacier, or hill. Since the density of air increases with lower temperature, the air will flow downwards, warming adiabatically as it descends, but still remaining relatively cold. Cold katabatic winds are frequently found in the early hours of the night when the solar heating has ceased and the ground cools by emitting infrared radiation. Cold air from extratropical cyclones may contribute to this effect. Over Antarctica and Greenland, prominent (although unnamed) cold katabatic winds exist,.
Velomobile - few manufacturers of velomobiles; many are homebuilt. Some models have the operator's head exposed; this has the advantage of giving the operator unobstructed vision, hearing, and some cooling, with the disadvantage of being more exposed to weather. A practical velomobile has many competing requirements. It should have as many of the following characteristics as possible. Light weight. Good visibility for the operator (clear front vision is especially important, but a 360 degree view is also desirable). Good maneuverability (steering, braking). Safety in collision and over bad roads. Good ventilation, including a windscreen defroster. This should be adjustable for more cooling in warmer weather. Many gears; a vehicle that is heavier but more aerodynamic than a bicycle needs a wider gearing range than a bicycle. Good aerodynamics. Good suspension. Reliable operation. Strength:.
Jam - its ripeness, but a rough starting point is equal weights of each. When the mixture reaches a temperature of 104°C, the acid and the pectin in the fruit react with the sugar, and the jam will set on cooling, but most cooks work by trial and error, bringing the mixture to a "fast rolling boil", watching to see if the seething mass changes texture, and dropping tiny samples on a plate to see if they run. How easily a jam sets depends on the pectin content of the fruit. Some fruits, such as gooseberries, redcurrants, blackcurrants, appless and raspberries, set very well; others, such as strawberries and ripe blackberries, need to have pectin added. There are proprietary pectin products on the market, and most industrially-produced jams use them. Home jam-makers sometimes.
James Harrison - machine followed in 1854 and his patent for a ether liquid-vapour compression refridgeration system was granted in 1855. Using a compressor upon a refrigerant gas, then forcing the compressed gas to pass through a condenser, where it cooled down and liquefied. The liquefied gas then circulated through the refrigeration coils and vaporising again, cooling down the surrounding system. The machine employed a 5m flywheel and produced 3000Kg of ice per day. Though he had commercial success establishing a second ice company back in Sydney in 1860, he later entered the debate of how to compete against the American advantage of un-refrigated beef sales to Britain. Presenting 'Fresh Meat frozen and packed as if for a voyage, so that the refrigerating process may be continued for any required period', and in 1873.
