Global warming is the rise in the average temperature of Earth's atmosphere and oceans since the late 19th century and its projected continuation. Since the early 20th century, Earth's mean surface temperature has increased by about 0.8 °C (1.4 °F), with about two-thirds of the increase occurring since 1980. Warming of the climate system is unequivocal, and scientists are more than 90% certain that it is primarily used by increasing concentration of greenhouse gases produced by human activities such as the burning of fossil fuels and deforestation. These findings are recognized by the national science academies of all major industrialized nations.
Climate model projections were summarized in the 2007 Fourth Amendment Report (AR4) by the Intergovernmental Panel of Climate Change (IPCC). They indicated that during the 21st century, the goal surface temperature is likely to rise a further 1.1 to 2.9 °C (2 to 5.2 °F) for their lowest emissions scenario and 2.4 to 6.4 °C (4.3 to 11.5 °F) for their highest. The ranges of these estimates arise from the use of models with differing sensitivity to greenhouse gas concentrations.
According to AR4, warming and related changes will vary from region to region around the globe. The effects of an increase in global temperature include a rise in sea levels and a change in the amount and pattern of precipitation, as well a probable expansion of subtropical deserts. Warming is expected to be strongest in the Arctic and would be associated with the continuing retreat of glaciers, permafrost, and sea ice. Other likely effects of the warming include a more frequent occurrence of extreme-weather events including heat waves, droughts and heavy rainfall, ocean acidification and species extinctions due to shifting temperature regimes. Effects significant to humans include the threat to food security from decreasing crop yields and loss of habitat from inundation.
Proposed policy responses to global warming include mitigation by emissions reduction, adaptation to its effects, and possible future geoengineering. Most countries are parties to the United Nations Framework Convention on Climate Change (UNFCCC), whose ultimate objective is to prevent dangerous antropogenic (i.e., human-induced) climate change. Parties to the UNFCCC have agreed that deep cuts in emissions are required, and that future global warming should be limited to below 2.0 °C (3.6 °F) relative to the pre-industrial level. Reports published in 2011 by the United Nations Environment Programme and the International Energy Agency suggest that efforts as of the early 21st century to reduce emissions may be inadequate to meet UNFCCC's 2 °C target.
Greenhouse gas
A greenhouse gas (sometimes abbreviated GHG) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. In the solar system, the atmospheres of Venus, Mars, and Titan also contain gases that cause greenhouse effects. Greenhouse gases greatly affect the temperature of the Earth; without them, Earth's surface would average about 33 °C (59 °F) colder than the present average of 14 °C (57 °F).
However, since the beginning of the Industrial Revolution, the burning of fossil fuels has contributed to the increase in carbon dioxide in the atmosphere from 280ppm to 397ppm, despite the uptake of a large portion of the emissions through various natural "sinks" involved in the carbon cycle. Anthropogenic carbon dioxide (CO2) emissions (i.e., emissions produced by human activities) come from combustion of carbon based fuels, principally wood, coal, oil, and natural gas.
Fossil fuels
Fossil fuels are oil, coal, and natural gas that originate from decayed plants and animals found in the Earth's crust. Because they take millions of years to form and are being used at such a rapid rate, fossil fuels are essentially a non-renewable source of energy. Even so, in 2005, more than three-quarters of the world's energy consumption was through the use of fossil fuels. They work to generate steam, electricity and power transportation systems. They make the manufacturing of tens of thousands of commercial goods possible. And although fossil fuels have become synonymous with modern industrial society, their potential to solve some of the challenges of everyday existence has been understood throughout history.
Use of fossil fuels produces around 21.3 billion metric tons of carbon dioxide per year. Carbon dioxide is, of course, one of the notorious greenhouse gases - the stuff directly responsible for global warming.
There are many potential alternatives to the use of fossil fuels (some of them can be rather fruity). These include biofuel, ethanol, and vegetable oil. Most scientists believe it's time for humans to address their addiction to fuels derived from decayed plants and animals and help fossil fuels go the way of the dinosaur.
Sources:
http://en.wikipedia.org/wiki/Global_warming
http://en.wikipedia.org/wiki/Greenhouse_gas
http://tlc.howstuffworks.com/family/fossil-fuel.htm
http://www.instituteforenergyresearch.org/energy-overview/fossil-fuels/
Friday, November 23, 2012
Sunday, November 18, 2012
infusion and tea
Infusion
Infusion is the process of extracting chemical compounds or flavors from plant material in a solvent such as water, oil or alcohol, by allowing the material to remain suspended in the solvent over time (a process often called steeping). An infusion is also the name for the resultant liquid.
A common example of an infusion is tea, and many tisanes are prepared in the same way. Lemon, chamomile, senna, apple, ginger, rooibos, and a great many other plants are used individually or in combination. Herbal infusions in water and oil are both commonly used as herbal remedies. Coffee can also be made through infusion (as in a French press), but it is more often made through percolation.
Tisane
Tisane or "herbal tea" is a catch-all term for any non-caffeinated beverage made from the infusion or decoction of herbs, spices, or other plant material. These drinks are distinguished from caffeinated beverages like coffee, maté, and the true teas (black, green, white, yellow, oolong, etc.), or from a decaffeinated tea, in which the caffeine has been removed. In addition to serving as a beverage, many tisanes are also consumed due to a perceived medicinal benefit.
Like brews made from the tea bush (Camellia sinensis), such infusions are prepared by combining hot water and fruits, leaves, roots or grains.
Tisanes can be made with fresh or dried flowers, leaves, seeds or roots, generally by pouring boiling water over the plant parts and letting them steep for a few minutes. Seeds and roots can also be boiled on a stove. The tisane is then strained, sweetened if so desired, and served. Many companies produce herbal tea bags for such infusions.
Flavored teas are prepared by adding other plants to an actual tea (black, oolong, green, yellow or white tea); for example, the popular Earl Grey tea is black tea with bergamot (the orange oil, not the herb of the same name), jasmine tea is Chinese tea with jasmine flowers, and genmaicha is a Japanese green tea with toasted rice.
Tea
Tea is an aromatic beverage commonly prepared by pouring hot or boiling water over cured leaves of the tea plant, Camellia sinensis. After water, tea is the most widely consumed beverage in the world. It has a cooling, slightly bitter, astringent flavor, which many people enjoy.
The phrase "herbal tea" usually refers to infusions of fruit or herbs made without the tea plant, such as rosehip tea or chamomile tea. Alternative phrases for this are tisane or herbal infusion, both bearing an implied contrast with "tea" as it is construed here.
Although single estate teas are available, almost all teas in bags and most other teas sold in the West are blends. Blending may occur in the tea-planting area (as in the case of Assam), or teas from many areas may be blended. The aim of blending is to obtain better taste, higher price, or both, as a more expensive, better-tasting tea may cover the inferior taste of cheaper varieties.
Some teas are not pure varieties, but have been enhanced through additives or special processing. Tea is highly receptive to inclusion of various aromas; this may cause problems in processing, transportation, and storage, but also allows for the design of an almost endless range of scented and flavored variants, such as bergamot (Earl Grey), vanilla, and caramel.
FURTHER READING
Caffeine
Caffeine is a bitter, white crystalline xantine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants. It is most commonly consumed by humans in infusions extracted from the seed of the coffee plant and the leaves of the tea bush, as well as from various foods and drinks containing products derived from the kola nut. Other sources include yerba maté, guarana berries, guayusa, and the yaupon holly.
In humans, caffeine acts as a central nervous system stimulant, temporarily warding off drowsiness and restoring alertness.
Percolation Percolation concerns the movement and filtering of fluids through porous materials.
In coffee percolation, soluble compounds leave the coffee grounds and join the water to form coffee. These soluble compounds are the chemical compounds that give coffee its color, taste, and aroma. Insoluble compounds remain within the coffee filter.
Decoction
Decoction is a method of extraction by boiling, of dissolved chemicals, from herbal or plant material, which may include stems, roots, bark and rhizomes. Decoction involves first mashing, and then boiling in water to extract oils, volatile organic compounds, and other chemical substances. Decoction can be used to make tisanes, teas, coffees, tinctures and similar solutions. Decoctions and infusions may produce liquids with differing chemical properties, as the temperature/preparation difference may result in more oil-soluble chemicals in decoctions vs infusions. The process can also be applied to meats and vegetables to prepare bouillon or stock.
A decoction is also the name for the resulting liquid. Although this method of extraction differs from infusion and percolation, the resultant liquids are often functionally similar.
Alkaloids
Alkaloids are a group of naturally occurring chemical compounds, that contain mostly basic nitrogen atoms. They are produced by a large variety of organisms, including bacteria, fungi, plants, and animals, and are part of the group of natural products.
Sources:
http://en.wikipedia.org/wiki/Infusion
http://en.wikipedia.org/wiki/Tisane
http://en.wikipedia.org/wiki/Tea
http://en.wikipedia.org/wiki/Caffeine
http://en.wikipedia.org/wiki/Percolation
http://en.wikipedia.org/wiki/Decoction
http://en.wikipedia.org/wiki/Alkaloid
Infusion is the process of extracting chemical compounds or flavors from plant material in a solvent such as water, oil or alcohol, by allowing the material to remain suspended in the solvent over time (a process often called steeping). An infusion is also the name for the resultant liquid.
A common example of an infusion is tea, and many tisanes are prepared in the same way. Lemon, chamomile, senna, apple, ginger, rooibos, and a great many other plants are used individually or in combination. Herbal infusions in water and oil are both commonly used as herbal remedies. Coffee can also be made through infusion (as in a French press), but it is more often made through percolation.
Tisane
Tisane or "herbal tea" is a catch-all term for any non-caffeinated beverage made from the infusion or decoction of herbs, spices, or other plant material. These drinks are distinguished from caffeinated beverages like coffee, maté, and the true teas (black, green, white, yellow, oolong, etc.), or from a decaffeinated tea, in which the caffeine has been removed. In addition to serving as a beverage, many tisanes are also consumed due to a perceived medicinal benefit.
Like brews made from the tea bush (Camellia sinensis), such infusions are prepared by combining hot water and fruits, leaves, roots or grains.
Tisanes can be made with fresh or dried flowers, leaves, seeds or roots, generally by pouring boiling water over the plant parts and letting them steep for a few minutes. Seeds and roots can also be boiled on a stove. The tisane is then strained, sweetened if so desired, and served. Many companies produce herbal tea bags for such infusions.
Flavored teas are prepared by adding other plants to an actual tea (black, oolong, green, yellow or white tea); for example, the popular Earl Grey tea is black tea with bergamot (the orange oil, not the herb of the same name), jasmine tea is Chinese tea with jasmine flowers, and genmaicha is a Japanese green tea with toasted rice.
Tea
Tea is an aromatic beverage commonly prepared by pouring hot or boiling water over cured leaves of the tea plant, Camellia sinensis. After water, tea is the most widely consumed beverage in the world. It has a cooling, slightly bitter, astringent flavor, which many people enjoy.
The phrase "herbal tea" usually refers to infusions of fruit or herbs made without the tea plant, such as rosehip tea or chamomile tea. Alternative phrases for this are tisane or herbal infusion, both bearing an implied contrast with "tea" as it is construed here.
Although single estate teas are available, almost all teas in bags and most other teas sold in the West are blends. Blending may occur in the tea-planting area (as in the case of Assam), or teas from many areas may be blended. The aim of blending is to obtain better taste, higher price, or both, as a more expensive, better-tasting tea may cover the inferior taste of cheaper varieties.
Some teas are not pure varieties, but have been enhanced through additives or special processing. Tea is highly receptive to inclusion of various aromas; this may cause problems in processing, transportation, and storage, but also allows for the design of an almost endless range of scented and flavored variants, such as bergamot (Earl Grey), vanilla, and caramel.
FURTHER READING
Caffeine
Caffeine is a bitter, white crystalline xantine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants. It is most commonly consumed by humans in infusions extracted from the seed of the coffee plant and the leaves of the tea bush, as well as from various foods and drinks containing products derived from the kola nut. Other sources include yerba maté, guarana berries, guayusa, and the yaupon holly.
In humans, caffeine acts as a central nervous system stimulant, temporarily warding off drowsiness and restoring alertness.
Percolation Percolation concerns the movement and filtering of fluids through porous materials.
In coffee percolation, soluble compounds leave the coffee grounds and join the water to form coffee. These soluble compounds are the chemical compounds that give coffee its color, taste, and aroma. Insoluble compounds remain within the coffee filter.
Decoction
Decoction is a method of extraction by boiling, of dissolved chemicals, from herbal or plant material, which may include stems, roots, bark and rhizomes. Decoction involves first mashing, and then boiling in water to extract oils, volatile organic compounds, and other chemical substances. Decoction can be used to make tisanes, teas, coffees, tinctures and similar solutions. Decoctions and infusions may produce liquids with differing chemical properties, as the temperature/preparation difference may result in more oil-soluble chemicals in decoctions vs infusions. The process can also be applied to meats and vegetables to prepare bouillon or stock.
A decoction is also the name for the resulting liquid. Although this method of extraction differs from infusion and percolation, the resultant liquids are often functionally similar.
Alkaloids
Alkaloids are a group of naturally occurring chemical compounds, that contain mostly basic nitrogen atoms. They are produced by a large variety of organisms, including bacteria, fungi, plants, and animals, and are part of the group of natural products.
Sources:
http://en.wikipedia.org/wiki/Infusion
http://en.wikipedia.org/wiki/Tisane
http://en.wikipedia.org/wiki/Tea
http://en.wikipedia.org/wiki/Caffeine
http://en.wikipedia.org/wiki/Percolation
http://en.wikipedia.org/wiki/Decoction
http://en.wikipedia.org/wiki/Alkaloid
Thursday, November 15, 2012
duty-free shop
Duty-free shops (or stores) are retail outlets that are exempt from the payment of certain local or national taxes and duties, on the requirement that the goods sold will be sold to travelers who will take them out of the country. Which products can be sold duty-free vary by jurisdiction, as well as how they can be sold, and the process of calculating the duty or refunding the duty component.
However, some countries impose duty on goods brought into the country, though they had been bought duty-free in another country, or when the value or quantity of such goods exceed an allowed limit. Duty-free shops are often found in the international zone of international airports and sea ports, but goods can be also bought duty-free aboard airplanes and passenger ships. They are not as commonly available for road or train travelers, although several border crossings between the United States and Canada have duty-free shops for car travelers.
Duty-free outlets were abolished for intra-EU travelers in 1999, but are retained for travelers whose final destination is outside the EU. They also sell to intra-EU travelers but with appropriate taxes. Some special member state territories such as Åland, Livigno, and the Canary Islands, are within the EU but outside the EU tax union, and thus still continue duty-free sales for all travelers.
Sources:
http://en.wikipedia.org/wiki/Duty-free_shop
However, some countries impose duty on goods brought into the country, though they had been bought duty-free in another country, or when the value or quantity of such goods exceed an allowed limit. Duty-free shops are often found in the international zone of international airports and sea ports, but goods can be also bought duty-free aboard airplanes and passenger ships. They are not as commonly available for road or train travelers, although several border crossings between the United States and Canada have duty-free shops for car travelers.
Duty-free outlets were abolished for intra-EU travelers in 1999, but are retained for travelers whose final destination is outside the EU. They also sell to intra-EU travelers but with appropriate taxes. Some special member state territories such as Åland, Livigno, and the Canary Islands, are within the EU but outside the EU tax union, and thus still continue duty-free sales for all travelers.
Sources:
http://en.wikipedia.org/wiki/Duty-free_shop
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