The first stroke is the intake stroke which the intake valve opens and the air and gas mixture enter the combustion chamber. ... The fourth stroke is the exhaust stroke then as the piston rises to the top of the cylinder the exhaust valve open and the exploded are released into the air. There are two main types of engine cooling, they are air-cooled and water-cooled. Air-cooled engine is an engine without anything but the main essentials of the engine. The water cooled engine is an engine with all the main essentials plus around each cylinder is something called a water jacket in which ...

• Word Count: 511
• Approx Pages: 2
• Grade Level: Undergraduate

Flat plate collectors are thin boxes with a see-through cover. ... They are more useful when it comes to air conditioning and central power generation. ... For the purposes of cooling, an absorption air conditioner uses a solar collector that stimulates the cooling process. ... These PV cells are commonly grouped into modules of about 40 cells. ... Energy would be converted to microwaves before being transferred to multiple antennae on Earth to be converted into electric power. ...

• Word Count: 720
• Approx Pages: 3
• Grade Level: Undergraduate

Instead some pores are filled with water, and others with air. ... An example of capillary forces exceeding gravity is capillary rise in a thin glass tube, where water is lifted upwards against the force of gravity. ... As a result, water in the unsaturated zone is preferentially drawn into small spaces over large ones, which tend to be occupied by air. ... Toxic waste that has leaked from containment facilities has seeped into the ground. ... The primary source of surface water is spring discharge from highly fractured plutonic rocks into streams along mountain foothills (INEGI, 1986). ...

• Word Count: 696
• Approx Pages: 3
• Has Bibliography
• Grade Level: Undergraduate

Agricultural expansion into forestland is the primary cause of tropical deforestation. ... Chemicals from waste dumps in some metropolitan areas are draining into backyards. Pesticides are leaking through the soil into drinking water wells in our agricultural belts. ... Refrigerators were designed to cool, but their coolants seep into the atmosphere and thin the Earth's protective shield. Americans want clean air, yet few are enthusiastic about the inconvenience of automobile exhaust inspections. ...

• Word Count: 700
• Approx Pages: 3
• Grade Level: Undergraduate

Gentle slopes are subject to sheet and rill erosion, in which the runoff removes a thin layer of top soil. ... Very small soil particles can be suspended in the air and carried away with the wind. ... Compaction rearranges soil particles; increasing the density of the soil and reducing porosity which preventing water movement into the soil and increasing runoff and erosion. ...

• Word Count: 797
• Approx Pages: 3
• Grade Level: Undergraduate

Today societies are at a crisis of history and how the actions of today will decide and determine whether the world goes up from here or continues to slide into a new dark era. It is important to understand that injustice doesn't just happen out of thin air. ... In Arthur Miller's The Crucible a small lustful unacceptable love story between John Procter and Abigail Williams transforms into a sinful plot that implicitly illustrates that in a theocratic society, heavy influence of religion constitutes corrupt power and authority that gains sufficient dominance and corruption to transfo...

• Word Count: 995
• Approx Pages: 4
• Grade Level: Undergraduate

Although opinions are various, they both consider global warming is climate change that is leading to an increase in the overall air and water temperature. ... Earth absorbs energy from the sun; at the same time, Earth re-radiates the energy back into space. Normally, the thin layer of atmosphere can trap a portion of the outgoing radiation, which keeps Earth's temperature within a comfortable region; nevertheless, the layer of atmosphere is being thickened by a great deal of carbon dioxide and other greenhouse gases caused by humans. ...

• Word Count: 1061
• Approx Pages: 4
• Grade Level: Undergraduate