Plastic is material consisting of any of a wide range of synthetic or semi-synthetic organic compounds that are malleable and so can be molded into solid objects.
Plasticity is the general property of all materials which can deform irreversibly without breaking but, in the class of moldable polymers, this occurs to such a degree that their actual name derives from this specific ability.
Plastics are typically organic polymers of high molecular mass and often contain other substances. They are usually synthetic, most commonly derived from petrochemicals, however, an array of variants are made from renewable materials such as polylactic acid from corn or cellulosics from cotton linters.
Due to their low cost, ease of manufacture, versatility, and imperviousness to water, plastics are used in a multitude of products of different scale, including paper clips and spacecraft. They have prevailed over traditional materials, such as wood, stone, horn and bone, leather, metal, glass, and ceramic, in some products previously left to natural materials.
In developed economies, about a third of plastic is used in packaging and roughly the same in buildings in applications such as piping, plumbing or vinyl siding. Other uses include automobiles (up to 20% plastic), furniture, and toys. In the developing world, the applications of plastic may differ—42% of India's consumption is used in packaging.
Plastics have many uses in the medical field as well, with the introduction of polymer implants and other medical devices derived at least partially from plastic. The field of plastic surgery is not named for use of plastic materials, but rather the meaning of the word plasticity, with regard to the reshaping of flesh.
The world's first fully synthetic plastic was bakelite, invented in New York in 1907 by Leo Baekeland who coined the term 'plastics'. Many chemists have contributed to the materials science of plastics, including Nobel laureate Hermann Staudinger who has been called "the father of polymer chemistry" and Herman Mark, known as "the father of polymer physics".
The success and dominance of plastics starting in the early 20th century led to environmental concerns regarding its slow decomposition rate after being discarded as trash due to its composition of large molecules. Toward the end of the century, one approach to this problem was met with wide efforts toward recycling.
Beef is the culinary name for meat from cattle, particularly skeletal muscle. Humans have been eating beef since prehistoric times. Beef is a source of high-quality protein and nutrients.
Most beef skeletal muscle meat can be used as is by merely cutting into certain parts, such as roasts, short ribs or steak (filet mignon, sirloin steak, rump steak, rib steak, rib eye steak, hanger steak, etc.), while other cuts are processed (corned beef or beef jerky). Trimmings, on the other hand, are usually mixed with meat from older, leaner (therefore tougher) cattle, are ground, minced or used in sausages. The blood is used in some varieties called blood sausage. Other parts that are eaten include other muscles and offal, such as the oxtail, liver, tongue, tripe from the reticulum or rumen, glands (particularly the pancreas and thymus, referred to as sweetbread), the heart, the brain (although forbidden where there is a danger of bovine spongiform encephalopathy, BSE, commonly referred to as mad cow disease), the kidneys, and the tender testicles of the bull (known in the United States as calf fries, prairie oysters, or Rocky Mountain oysters). Some intestines are cooked and eaten as is, but are more often cleaned and used as natural sausage casings. The bones are used for making beef stock.
Beef from steers and heifers is similar. Depending on economics, the number of heifers kept for breeding varies. The meat from older bulls, because it is usually tougher, is frequently used for mince (known as ground beef in the United States). Cattle raised for beef may be allowed to roam free on grasslands, or may be confined at some stage in pens as part of a large feeding operation called a feedlot (or concentrated animal feeding operation), where they are usually fed a ration of grain, protein, roughage and a vitamin/mineral preblend.
Beef is the third most widely consumed meat in the world, accounting for about 25% of meat production worldwide, after pork and poultry at 38% and 30% respectively. In absolute numbers, the United States, Brazil, and the People's Republic of China are the world's three largest consumers of beef; Uruguay, however, has the highest beef and veal consumption per capita, followed by Argentina and Brazil. According to the data from OECD, the average Uruguayan ate over 42 kg (93 lb) of beef or veal in 2014, representing the highest beef/veal consumption per capita in the world. In comparison, the average American consumed only about 24 kg (53 lb) beef or veal in the same year, while African countries, such as Mozambique, Ghana, and Nigeria, consumed the least beef or veal per capita.
In 2015, the world's largest exporters of beef were India, Brazil and Australia. Beef production is also important to the economies of Uruguay, Canada, Paraguay, Mexico, Argentina, Belarus and Nicaragua.
Beef production has a high environmental impact per gram of protein.
Packaging is the science, art and technology of enclosing or protecting products for distribution, storage, sale, and use. Packaging also refers to the process of designing, evaluating, and producing packages. Packaging can be described as a coordinated system of preparing goods for transport, warehousing, logistics, sale, and end use. Packaging contains, protects, preserves, transports, informs, and sells. In many countries it is fully integrated into government, business, institutional, industrial, and personal use.< BACK | NEXT >