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Advantages and disadvantages of aerosols
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Aerosol Spray Cans
Spray cans produce an aerosol, the technical term for a very fine spray.
They do this by means of a pressurized propellant, which is a liquid that boils at everyday temperatures. Inside the can, a layer of gaseous pressure increased, and eventually it becomes so high that boiling stops. when the nozzle is pressed, the gas pressure forces the product up the tube in the can and out of the nozzle in a spray or foam. The propellant may emerge as well but, now under less pressure, it immediately evaporates.
First patented in the US in 1941, aerosol spray cans have been used as convenient packages for an ever increasing range of products including paints, insecticides, and shaving cream to name a few. The can is filled with the product to be sprayed and the propellant, a compressed gas such as butane or
Freon. The gas is partly liquefied by the pressure in the can, but there is a layer of free gas above the liquid. As the can empties liquefied gas vaporizes to fill the space.
The valve is normal held shut by the pressure in the can, and by the coil spring directly below the valve stem. When the push button is pressed, it forces the valve stem down in its housing, uncovering a small a small hole which leads up through the stem to the nozzle in the button. This allows the product to be forced up the dip tube by the gas pressure in the can. The nozzle is shaped to give a spray or a continuous stream.
To produce a fine mist, a propellant is used which mixes with the product. The two leave the nozzle together and the propellant evaporates a soon as it reaches the air, breaking the product in to tiny droplets. The same technique used with a more viscous liquid and a wider nozzle results in a foam.
For a continuous stream of liquid or more viscous material, a nonmixing propellant is used, and the dip tube reaches into the product.
The widespread use of aerosol cans using Freon as the propellant led scientists to believe by the late 1970s that the ozone layer in the upper atmosphere, which filters out harmful Ultraviolet radiation from the sun, could be destroyed by the large quantities of fluorocarbons in the gas being release into the air. Federal controls were introduced to ban the use of Freon, and other propellants are now employed, notably butane which, however is dangerously flammable. Among young people in United States, conventional drug or alcohol abuse has given away-for an increasing number of teen-agers-to a practice called
After the rinses, close the stopcock and fill the buret up to the 0.00mL line with NaOH. Quickly, open the stopcock to fill the tip of the buret and then close the stopcock. Record the initial volume of the NaOH to the nearest 0.01mL.
1.Intake: The intake valve opens allowing fresh oxygen rich air mixed with fuel to enter the cylinder.
In 2010, there was a huge oil spill near the Gulf of Mexico that we now know as the BP Oil Spill today. The Spill sent about 170 million barrels of crude oil into the Gulf of Mexico. The spill killed 11 men aboard the deep-water Horizon. The BP Oil Spill impacted the environment very negatively. There were different types of environmental impact as a result of the Oil Spill, but the two that grabbed my attention the most are the Polluted Air and the Contaminated Food Chain. The first impact that grabbed my attention was the Polluted Air. Because of the Oil Spill, the air around the surroundings neighborhoods was polluted. All the lightest chemicals in the oil that had spill evaporated within hours of the incidence forming air pollution particles. These particles that are in the air poses significant threats to the human health from being inhaled. The chemical found in the particles that was formed is known as Volatile, which has been known to cause respiratory irritation and central nervous system depression (Solomon & Janssen, 2010). The second impact that grabbed my attention was the contamination of the food chain, specifically the food chain of sea animals that lives near the Gulf of Mexico. Scientists found traces of oil in zooplanktons; this could only mean that the sea creature has had contact with the spilled oil. According to the Staff at Houston Business Journal (2012), “Baby fish and shrimp feed on the tiny, drifting zooplankton, and then introduce contamination and pollution to the larger sea creatures in the food web.” With these findings, it isn’t going to take long before the baby fishes become grown and caught by fishermen and before we know it, it’s on our dinner plate. And here we are eating fishes w...
The Treaty of Versailles, initially created to keep peace in Europe and ensure that another war like World War I wouldn’t happen again, had in fact, backfired and spiraled the world down into a deeper, bloodier battle. The treaty discriminated strongly against Germany, with the loss of territories, military restrictions, economic reparations, and the War Guilt Clause. It caused humiliation and anger within Germany, and led to Hitler and the Nazi Party coming to power. World War II was not only started by Adolf Hitler and Germany, but had a lot to do with the humiliation that Germany felt when the terms for the Treaty of Versailles were laid down. The harsh terms of the Treaty of Versailles may be indirectly related to the cause of World War II, but nonetheless was a huge factor in starting the war.
The common gasses used in diving include compressed air and Nitrox. Nitrox is a mixture of gas composed of nitrogen and oxygen. Nitrox also contains normal air, which is 78% nitrogen, 21% oxygen and 1% of other gasses, primarily argon.
The Treaty of Versailles was one of the peace treaties at the end of World War I, which was a war between the Central Powers (Germany, Austro-Hungarian Empire, etc.) and the Allied Powers (Great Britain, France, Russia, Japan, America, etc.). It ended the state of war between Germany (the Central Powers) and the Allied Powers. It was signed on 28 June 1919, exactly five years after the assassination of Archduke Franz Ferdinand, the reason of starting World War I.
After the oil/gas mixture is drawn from the ground, it is then stored into a storage tank and allowed to rest for a while. Then the gas is piped off to a set of distillation columns to clean up the ethane. In order to activate the chemical reaction necessary to separate the ethane, a thermal cracking unit (a sort of long heated tube) i.e. a plug flow reactor is used. After a series of distillations, ethylene exits the tube.
The chemicals produce gases, there... ... middle of paper ... ... nched from North Korea and fell after flying for just over a minute," Japanese Defence Minister Naoki Tanaka said. ”(-North). Also America’s defense secretary Chuck Hagel defends this case saying “neither Iran nor North Korea is capable of attacking the United States with a missile armed with a nuclear warhead.
This fluid is made up of 32.5% urea in 67.5% de-ionized water. This mixture is then injected into the exhaust stream using an advanced catalyst system. When DEF is released into the exhaust stream the hot exhaust causes the fluid to release ammonia which then breaks down the greenhouse harming gas of NOx into nitrogen and water. This fluid must be refilled at approximately every 10,000 miles (Voelcker).
The Gulf of Mexico oil spill has had an extremely negative effect on the surrounding wildlife and ecosystem. The oil spread across the gulf contaminating any living organism that came into direct or indirect contact with it. The oil cuts off the ability of oxygen from the air to move into the water which directly harms fish and other marine wildlife that require that oxygen. The dispersant that the BP is using to try and break up the oil moves the slick into the entire water column which contaminates the ocean floor which would most likely not have seen any damage if it wasn’t for the use of these dispersants. More than 400 species that live in the Gulf Islands and marshlands are at risk and as of November 2 s...
...ave large diameter to give least flow resistance. It has valves to prevent low pressure blood flowing backwards.
often done by electrical discharge in a pure gas - or gas mixture - in a tube.
In October 1918 the German government came forward to the U.S. president Woodrow Wilson to make a general armistice (Encyclopedia Britannica). Germany accepted Woodrow Wilson’s treaty but the other allies demanded that German pay for the damage they have caused all over Europe. After all negotiations were over the Treaty of Versailles was signed 28th of June 1919, but America never signed the treaty because the USA Germany had little to no say of what was put into the treaty and the allies knew that the German government would adhere to any conditions. German knew they had been beaten and needed to stop the war at all cost which gave the allied powers free range on whatever they thought the German people should pay. The treaty cut a mass chunk out of the land that German had owned, depleted their allowed
... In an industrial production, the water and fat and forced through a narrow slit at high pressure, breaking the fat droplets and dispersing them. The size is usually less than one thousandth of a millimeter. The mixed is pumped into the tank room, which is at 36 degrees and is there for four to eight hours. Afterwards the mix is pumped to the flavor tank, where a tank holding 500 gallons of ice cream is transformed into ice cream with different flavors.