Physics is the the study of matter and its spatial motion; while it embraces the levels of nucleii, elementary particles and atoms, its domain relative to molecules and their interactions is more properly termed chemistry. The motion of particles is governed by the basic laws of physics including Newtonian mechanics (for large objects); electromagnetism; thermodynamics and quantum mechanics (in the case of molecular and smaller entities). The earliest forms of physics addressed are motions of celestial objects, and presently this field can be viewed as astrophysics. Physics also embraces the notions of the Theory of Relativity, so that the duality of space and time is addressed. Chemistry has taken on added importance in the last half century as the bridge between fundamental laws of nature and the understanding of cellular processes and replication of DNA, the basic molecule of organism genetic coding.
Aluminum is a silver-white metal, very low density (less than three times as dense as water), yet relatively strong. In addition, aluminum is ductile; that is, it can be drawn...
Earth's atmospheric airLast Updated on 2014-04-02 14:56:48The Earth's atmospheric air is a colorless, odorless and tasteless mixture of gases consisting mostly of nitrogen (N2) and oxygen (O2). It is the part of Earth's atmosphere that humans and all other animals breathe in order to obtain the oxygen needed to sustain life.
The Earth's atmosphere not only contains the air we breathe, it also holds clouds of moisture (water vapor) that become the water we drink. Furthermore, it protects us from meteors and harmful solar radiation and warms the Earth's surface by heat retention. In effect, the atmosphere is an envelope that protects all life on Earth.
The air may contain pollutants that originate from a variety of sources such as our industries and our vehicles, and can directly or indirectly affect our health and the natural environment. These effects may be experienced near the sources of air pollution and some air... More »
Energy qualityLast Updated on 2014-03-06 16:45:22
Energy quality refers to differences in the ability of a unit of energy to produce goods and services for people. The usefulness of an energy system is determined by a complex combination of physical, technical, economic, and social attributes. These include gravimetric and volumetric energy density, power density, emissions, cost and efficiency of conversion, financial risk, amenability to storage, risk to human health, and ease of transport. No single metric of an energy system captures all such attributes. It stands to reason, therefore, that a comprehensive and balanced comparison of energy technologies should employ a range of metrics, with their strengths and weaknesses duly noted.
The most common way to measure energy is by heat content because all forms of energy can be completely converted to heat (Btus, joules, calories, kilowatt-hours). The aggregation of... More »
Carbon monoxideLast Updated on 2014-01-16 09:44:12Carbon monoxide (CO), also referred to as carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. Exposure to high levels of carbon monoxide is extremely toxic to humans and animals. Conversely, small amounts of carbon monoxide are produced in normal animal metabolism and it is thought to have some normal biological functions.
Carbon monoxide consists of one carbon atom and one oxygen atom. It is the simplest member of the class of inorganic compounds known as oxocarbons which includes carbon dioxide (CO2), carbon suboxide (C3O2), mellitic anhydride (C12O9) and many others. When combined with a metal (i.e. an organometallic complex), the carbon monoxide is a ligand called carbonyl: for example, in nickel carbonyl with the formula Ni(CO)4.
Carbon monoxide is produced by the partial combustion of carbon-containing substances. It is produced... More »
Astronomy of ChristmasLast Updated on 2014-01-02 16:06:37The astronomy of Christmas is chiefly centered around verifiable celestial events that occurred at or near the time of birth of Jesus. Astromers have expended considerable research on reconstructing movements of planets, stars and comets that could best explain Biblical accounts of the era.
The Christian New Testament Gospel of Matthew, includes description of three "Maji" from the east who follow the Star of Bethlehem to the location where they find Jesus shortly after his birth. For example, the Gospel of Matthew, Chapter 2, verse 1 of the New International Version of the Bible gives:
After Jesus was born in Bethlehem in Judea, during the time of King Herod, Magi from the east came to Jerusalem and asked, “Where is the one who has been born king of the Jews? We saw his star when it rose and have come to worship him."
Movements of celestial bodies in this era... More »
HydrodesulfurizationLast Updated on 2013-12-15 23:43:02Hydrodesulfurization (HDS) or Hydrotreating is a catalytic chemical process widely used to remove sulfur compounds from refined petroleum products such as gasoline or petrol, jet fuel, diesel fuel, and fuel oils. One purpose for removing the sulfur is to reduce the sulfur dioxide emissions resulting from using those fuels in automotive vehicles, aircraft, railroad locomotives, ships, or oil burning power plants, residential and industrial furnaces, and other forms of fuel combustion.
Another important reason for removing sulfur from the intermediate product naphtha streams within a petroleum refinery is that sulfur, even in extremely low concentrations, poisons the noble metal catalysts platinum and rhenium in the catalytic reforming units that are subsequently used to upgrade the of the naphtha streams.
Hydrogenation of the sulfur compounds results in the formation of undesirable,... More »
Drag and drop the content to change the order of featured content. The top nine will be displayed.