Composites are materials made from two or more constituent materials that are combined to produce unique properties. Concrete is a common composite made of cement (binder) and gravel (reinforcement), and rebar can be added to make it stronger. Plastics composites are made of synthetic polymers like hydrocarbons and alcohols. Dental composites are synthetic resins used as restorative materials and adhesives in dentistry. Polymer composites use long chains of bonded molecules called polymers, commonly known as plastics or resins. The earliest uses of composites date back to 1500 BC by ancient Egyptians and Mesopotamians who used mud and straw mixtures for building. Later, Mong
This document discusses several topics related to nanotechnology:
- Carbon nanotubes are hexagonal networks of carbon that are just nanometers in size and have extraordinary mechanical and thermal properties. They were first discovered in 1991 and have applications in electronics.
- Smart textiles are fabrics that can function electrically through embedded computing and digital components. They originated in the 1990s for military use and now have applications in healthcare like monitoring vital signs.
- Nanoflakes are a new material discovered by Martin Aagesen that form a perfect crystalline structure allowing absorption of all light, making them promising for highly efficient solar cells. Their use could significantly reduce the cost of solar energy production.
PVC is a polymer derived from sodium chloride and oil or natural gas. It is a white, odorless powder that is light, non-flammable, and resistant to chemicals and compression. PVC can be recycled and has many applications, as it does not degrade in water and has a long service life. Common uses of PVC include wire and pipe insulation, construction materials, toys, automotive parts, medical devices, and more.
Este documento describe el metacrilato y el polipropileno, dos plásticos sintéticos. El metacrilato fue desarrollado en 1928 como un sustituto del vidrio que es más ligero y resistente a los golpes. Se usa comúnmente en ventanas, vitrinas y letreros. El polipropileno fue descubierto en 1954 y se ha utilizado ampliamente en la industria desde la década de 1950 debido a su resistencia química y mecánica. Ambos plásticos tienen muchas aplicaciones como materiales de
Coltan is a black metallic ore that is mined primarily in the Congo. It was discovered by a pygmy man who used the stone to sharpen weapons. When refined, coltan becomes a heat-resistant powder that can hold a high electrical charge, making it useful for tantalum capacitors found in many electronic devices as well as high-temperature alloys for turbines. While controversial to exploit due to mining practices, coltan can be recycled and reused through proper waste management and smelting techniques.
Polystyrene is a synthetic polymer made from styrene monomer. It can be rigid or foamed, and general polystyrene is clear, hard and brittle. Polystyrene was discovered in 1839 by Eduard Simon and has a variety of applications including packaging, insulation and construction. While polystyrene has good thermal and electrical insulation properties, it is not widely recycled due to its non-biodegradable nature which poses environmental challenges.
Carbon fibers are composed of carbon atoms bonded together in sheets, similar to graphite. They were first created in 1958 and are now made from petroleum pitch. Carbon fibers have high strength and stiffness but low density, making them useful for applications in aerospace, automotive, sports equipment, and other industries where lightweight strength is important.
Carbon fibers are composed of carbon atoms bonded together in sheets, similar to graphite. They were first created in 1958 and are made by heating rayon or petroleum pitch. Carbon fibers have high strength and stiffness but low density, and are used in aerospace, automotive, sports equipment, and other applications.
Polyethylene was first synthesized in 1898 by German chemist Hans von Pechmann by accident while heating diazomethane. In 1933, Reginald Gibson and Eric Fawcett at ICI Laboratories synthesized polyethylene as it is known today. Polyethylene has several characteristics including being an excellent electrical insulator, transparent or opaque, resistant to low temperatures, hygienic and safe, inert to chemical attack, an excellent moisture barrier, and economic. Polyethylene has many uses such as bags, coating ditches, food and industrial packaging, disposable nappies, serum bags, containers, pipes, bottles, and irrigation pipes. Polyethylene is recyclable and can be melted and transformed into new products like
This document summarizes information about aluminium, titanium, biochips, and biosensors. It describes aluminium and titanium as lightweight metals that are abundant in nature. Aluminium is a silvery white metal commonly used in transportation, construction, and packaging. Titanium is stronger than steel and highly corrosion resistant, making it useful in aerospace applications and implants. The document also notes that biochips can perform many biochemical reactions simultaneously for screening and detection, while biosensors combine biological and physical elements to detect analytes.
Aluminum and titanium are described along with their properties and common uses. Aluminum is a light, silvery metal that is abundant in nature and commonly used in electricity, transportation, construction and packaging. It can be recycled infinitely without loss of properties. Titanium is also described with its discovery, properties as a transition metal, and common uses in alloys, aerospace, surgery and other industries. Biochips and biosensors are also summarized, with biochips enabling simultaneous biochemical reactions for screening and detection, while biosensors combine a biological component with a transducer and detector for analytical purposes.
The document discusses steel and stainless steel. It defines steel as an alloy of iron with carbon as the primary alloying element. Steel was first produced around 4,000 years ago and is strong, resistant to corrosion, and 100% recyclable. Stainless steel is an alloy of iron, chromium, and nickel that does not rust or stain easily. It was discovered in 1913 and is used widely in cookware, buildings, transportation and industrial equipment due to its corrosion resistance, strength and recyclability. Both steel and stainless steel can be recycled repeatedly without loss of quality, saving resources and reducing environmental impact with each recycling.
This document discusses three types of rubber: natural rubber, synthetic rubber, and neoprene rubber. Natural rubber comes from latex and trees, was used by ancient civilizations, and is used today mainly for tires and hoses. Synthetic rubber is made from petroleum, was invented in 1909 as a cheaper alternative to natural rubber, and accounts for two-thirds of rubber production today. Neoprene is a synthetic rubber made from chloroprene polymerization that is chemically stable over a wide temperature range and used for products like wetsuits and boots.
Silicon is a chemical element with an atomic mass of 14 that occurs in crystal or amorphous form. It is a semiconductor used in electronic chips, solar cells, and other technologies due to its strength, thermal conductivity, and elasticity. Graphene is an allotrope of carbon consisting of a single layer of carbon atoms arranged in a hexagonal lattice. It was discovered in 2004 by Andre Geim and Konstantin Novoselov, who won the Nobel Prize. Graphene has unique properties including high strength, thermal and electrical conductivity, and transparency. Potential uses include shielding, electronics, vehicles, and information technologies.
Ardipithecus is a genus of early hominid found in Ethiopia that lived approximately 4.4 million years ago. It is considered a descendant of Orrorin tugenensis and a direct ancestor of australopithecines. There were two species, A. ramidus and A. kadabba. A. ramidus had a skull similar in size to great apes and evidence shows it moved in a bipedal manner. New evidence from the Aramis site in Ethiopia, where a partial skeleton of A. ramidus was found, indicates through sedimentological and isotopic analysis that it lived in a river-margin forest within a savanna landscape, in
Coronary heart disease is caused by plaque buildup in the coronary arteries that supply blood to the heart. Over many years, plaque narrows the arteries and reduces blood flow. If plaque ruptures, a blood clot can block blood flow and cause a heart attack. A heart attack occurs when an area of the heart muscle dies from lack of oxygen-rich blood. Angina is chest pain that occurs when blood flow to the heart is reduced. Coronary heart disease is the leading cause of death in the United States and lifestyle changes, medicines, and procedures can help prevent and treat it.
La gripe española de 1918 fue una pandemia mortal que mató entre 50-100 millones de personas, mientras que la gripe A de 2009 causó síntomas graves similares a la gripe común pero más severos. Ambas enfermedades se transmiten por vía aérea a través de gotitas al toser o estornudar, y su prevención requiere evitar lugares concurridos y el contacto con personas enfermas.
Dengue fever is an infectious tropical disease caused by the dengue virus and transmitted by Aedes mosquitoes. Symptoms include fever, headache, and joint pains, and in rare cases it can develop into dengue hemorrhagic fever resulting in bleeding and organ failure. The dengue virus infects 50 to 390 million people worldwide annually, leading to thousands of deaths, especially in Southeast Asia.
La malaria es una enfermedad grave causada por parásitos del género Plasmodium transmitidos por la picadura de mosquitos. Provoca fiebre, dolores musculares y puede ser mortal, causando entre 2-3 millones de muertes anuales a nivel mundial. A pesar de los esfuerzos, todavía no existe una vacuna completamente efectiva contra la malaria.
La malaria es una enfermedad grave causada por parásitos del género Plasmodium transmitidos por la picadura de mosquitos. Provoca fiebre, dolores musculares y puede ser mortal, causando entre 2-3 millones de muertes anuales a nivel mundial. A pesar de los esfuerzos, todavía no existe una vacuna completamente efectiva contra la malaria.