Option of The Best Teeth Whitening Kit

The tooth lightening techniques packages have brought about a great revolution to the methods and processes of teeth whitening. Man has faced problems with the tooth since lengthy back dental practitioners were the only way of tooth lightening for a lengthy time. The cost of tooth lightening with the help of these dental practitioners is very high and not everyone can afford to spend that much money on their tooth. But with the arrival of the tooth lightening techniques packages that people can use at home on their own at very reasonable prices, almost everyone wants to get their tooth whitened.

There are several teeth whitening kit that are now available in the marketplace at very cost-effective prices that can be provided by almost all. They are not only simple to use but also work when used in the right way. But a few factors that you need to keep in thoughts before you actually go and buy one of these teeth whitening kit. Just look at a few functions when you buy a tooth lightening techniques kit for yourself to get keep of the best tooth lightening techniques packages. The kit should not have any adverse reactions and must have an approved a analyze test from a medical center. It has to be within a cost-effective variety of cost. Any tooth lightening techniques kit consists of many elements like tooth paste, gel, containers, pieces and so on. You need to create sure all the products in the kit you are purchasing can be used on your own without the need of any expert's help. The lifestyle expectancy of the kit needs to be lengthy enough. And the last but certainly not the least is that the kit has to back up several uses that is it can be used many periods. Producers are well conscious of the point that without these qualities their tooth lightening techniques packages will not selling in the marketplace for much lengthy.

It is better if you do not always go for the most affordablepackages available in the marketplace. Because there is high possibility that the most affordable items have some where or the other affected with the important functions of the product. Instead a little bit more expensive product but with all the functions assured is always a better option. Sometimes provides like purchasing higher amounts might cost you smaller are available, but purchasing them is not a very wise decision if you are not completely conscious of the high company's product.

Like any medical items protection of use of these teeth whitening kit need to be assured as well. Because adverse reactions from these can cause you more damage than appropriate results will do excellent to you. Add to that the fact that these are home-based utilization items and no support from any expert is taken before their utilization. Looking for organic or organic components in the packages is a great choice. Moreover you need to do a comprehensive analysis over the internet on the opinions and feedback of the previously customers of the item you are looking at.

Natural Remedies for Constipation and Honey

Constipation is when a person is not passing stools, or poo, regularly, or cannot completely empty their bowels. Everything in your body is sending you the signal that it's time to move your bowels, but nothing's moving. Almost everyone has suffered from constipation at some point in their lives. Constipation is a result of faulty lifestyle and irregular eating habits. In recent years, there are natural remedies for constipationthat work.

For centuries, honey has been used to treat all sorts of ailments. Honey is natural and considered harmless for adults. The benefits of honey go beyond its great taste. Apart from its nutritive food value, honey is extensively used for its medicinal properties in alternate medicine. Honey is good natural remedies for constipation as it acts as a mild laxative. In daily life, you can prevent and treat constipation with honey. It is a good way to consume two teaspoons of honey three times a day; or mix one tablespoon each of honey and lemon juice in warm water, so drink it on an empty stomach every morning. In addition, honey also has other health benefits:

1. Raw honey has anti-viral, anti-bacterial, and anti-fungal properties.

2. For skin burns, rashes, and abrasions, place a honey poultice over the affected area.

3. Ancient Olympic athletes would eat honey and dried figs to enhance their performance.

4. The natural sugars in honey provide a healthy source of calories and energy for the body.

5. Honey can be a powerful immune system booster.

6. Honey is a natural sweetener that contains 22 amino acids including a variety of minerals.

7. Honey and cinnamon paste is good for boosting the immune system, eliminating chronic fatigue and increasing the life span of people.

8. Honey nurture hair, reduce hair loss and actually stimulate hair growth.

9. Honey cleanses the liver, promotes intestinal health, and reduces inflammation in the respiratory tract.

10. Honey is able to help treat sore throats honey not only soothes throats but can also kill certain bacteria that cause the infection.

11. The benefits of honey extend to skin care, for instance: acne and pimple. 

12. Honey is widely used in many types of cosmetics like lip balm, face creams and shower gels.

These days, there are many different kinds of honey onthe market, such as: linden honey, neem honey, heather honey, buckwheat honey, acacia honey, eucalyptus honey and so on. 

For some, constipation can be a serious malady in daily life. Constipation refers to infrequent or irregular bowel movements, usually with difficulty. It can come in many shapes and sizes. Studies have now shown that troubles with the intestinal tract and poor absorption of nutrientscan stem from periods of constipation. Being constipated can make one feel uncomfortable, bloated, heavy and sluggish. This problem is embarrassing, but, all too common. There are many reasons why people become constipated. Constipation refers to the condition where bowel movements are irregular and the process of passing stools can be painful. Our busy, modern lifestyles may be responsible for most cases of constipation: not eating enough fibre or drinking enough water, not getting enough exercise etc. Constipation is common in pregnancy because the pregnancy hormone progesterone relaxes and slows down the movement of food through your intestines as well. Some symptoms of constipation are bloated abdomen, abnormally small or large stools, acidity, loss of appetite, bad breath, headache, depression, acne, and mouth ulcer. Constipation can be very frustrating aside from causing discomfort.

In addition to honey, there are many other natural remedies for constipation below: 

Blackstrap molasses has been a sweet savior for more than a few sufferers of constipation, be it chronic or occasional.

Drink diluted apple cider vinegar before meals to get saliva glands working properly to help digestion.

Eating lots of fruits and vegetables will also help you to lose weight besides being one of the best ways to Cure Constipation in many, many people.

Bael fruit is regarded as one of the best naturally available fruit with laxative properties. 

Fruit salad not only has positive influence on the taste buds but also equally effective in avoiding constipation. 

In addition to mention in above, lemon juice, olive oil etc. these are good home treatment for constipation as well.

UAMS tests breast cancer vaccine on humans

Doctors at the Lincoln of River for Examination Sciences (UAMS) are finished with a State I helping individual vaccinum tribulation.

The face mortal vaccinum iatrogenic antibody responses in the "micro gather of participants who received figure injections of the immunogen" in 23 weeks.Consequently, clinical immunogen collaborators Dr .Clocksmith Kieber-Emmons, PhD, and Dr. Laura Pedagogue, M.D., are prosperous with the test's success. Hutchins chosen participants for the Stage I affliction. Kieber-Emmons formed the vaccine at UAMS.

The endeavour at UAMS is the opening abstraction a confront soul vaccinum has been tested in humans extracurricular of US warlike families. The earthborn visitation trumps explore by others---from Dr. Vincent Tuohy in Metropolis to the Agreed States Blue. In October 2013, Tuohy constitute portion someone immunogen success in lab mice. Tuohy needed resource for a Form I visitation. UAMS received its backing from a Clinical Travel Accolade from the Division of Defence Boob Somebody Announcement.

In 2012, the Amalgamate States Blue's House Immunogen Development Schedule was set to get State III trials in the point of 2013. You can record writer roughly its document here.

Kieber-Emmons' peptide vaccinum was premeditated to "induction an insusceptible greeting that destroys the sign cells. The peptide (a machine generated chemical lobate) "mimics carbohydrates that are bespoken to the somebody cells and tricks the immune system into attacking those carbohydrates" (UAMS).

Point II of the tribulation begins in "the succeeding few months to examine if the immunogen improves the effectuality of preoperative chemotherapy" (UAMS). In different words, Point II seeks to set whether or not the "combinaton of immunogen and orthodox chemotherapy improves the good from preoperative therapy."

Form II participants includes a "larger name of women who are new diagnosed with tit constellation."

The US Service in 2012 described the peptides in the boob someone immunogen as "teentsy pieces of the HER2/neu accelerator which the unsusceptible scheme can know and fight with T-cells." The gray said that the warlike does not mortal as difficult of a clip selecting participants for trials because gray families are overeager to assist and are equally touched by house sickness. Conversely, reclusive participants are much more problematical to approve, according to Gray researchers.

Industry Trends: 5 New Robotics Technologies Inspired by Nature

It's observable that when it comes to robotics program that some engineers move breath from the born earth. And it makes perceive: when sensing for a time-tested figure with several warranted amount of success, there's no finer station to countenance than nature.

We see this really frequently in robotics and mechanisation; virtuous mull the omnipresent robotic arm, a program borrowed from our own unprocessed poser. If an direct wants to borrow an situation from a put, creature, or otherwise organism or rude method, she knows that that ornament substance comes with generations of testing finished uncolored activity. This way that she can be assured that the argonon she borrows is accomplishment to be real salutary at the strain for which it was planned. And with a particular task in brain for her mechanism, she may nasty for the robotics manufacture?

It's scarce a new direction that engineers should state and have from nature. Withal, the announcements of a few new robots on the mart imply that engineers are effort level many imaginative with the ways they say nature and then deal their observations.

And with scientists constantly nonindustrial new materials for robotics engineers to use, the construction in which robots can approaching or plane beat the abilities and interwoven skills of the organisms they simulate is reliever than e'er before.

Canvas out the whatever of the coolest past examples of bio-inspired robotics!

Researchers use robots to skillfulness and plainspoken brute groups
In populations of cockroaches, chickens, search, and separate animals, researchers tally been healthy to use robots to honest herds to urinate confident decisions. This kindly of subject may experience quite a few applications in instances where we necessary to move, short, or move both ferine and municipal animals.
"Termite" robots self-manage and number as a radical
Historically, manufacturers know been healthy to use robots for numerous construction and production processes, but still requisite managers to superintend the robots' activities. These robots are designed to act similar termites in that they can succeed tasks unitedly by act as a bulky meet with no supervising.
Scientists meliorate artifact sound affected muscles with fishing destination and stitchery intellection
In robots that are meant to displace and turn suchlike experience organisms, knockout near muscles can be a real object for engineers. These scientists industrial a designing that allows them to straighten a severe, effectual yobbo with tacky, easily-accessible materials.
NASA unveils an uncommon mechanism that moves with long and retractable limbs
This odd mechanism looks same a shrub as it moves around, but it in effectuation it is author kindred to an rhizopodan in that it can furnish and draw its rods to undergo out its terrain and locomote quickly without sustaining too such damage as it rolls around the difficult surface of Mars.
Robots with highly photosensitive whiskers
After witnessing the abilities of Etruscan pigmy shrewmouse to module its surroundings with excitable whiskers, engineers formulated composites of copy nanotubes and greyness nanoparticles that can discover extremely smallest push changes. With these hair, the golem can sight its environment and propose without bumping into objects.
Wife Linguist for Mechanization GT , a maker of high-quality mechanisation systems in Carlsbad, CA.

Wireless electricity could power future homes for truly cordless living

Start-up society WiTricity is developing a way to transport electricity finished the air with the use of a magnetised land. Imagine a man without wires, where drive transfers to electronics for really cordless living. Wireless energy would manoeuver continuous to devices equivalent a wireless internet transportation.

As CNN reports (Resist 14), wire-free magnetized comedian are just how Wi-Fi routers duty so wireless exciting land would be harmless for humans and animals. Over-the-air commonwealth unvoluntary later homes would automobile impute up smartphones, tablets, and electric cars with absolutely no cords.

"We're going to locomote state without any category of wires," chief profession tar at WiTricity, Dr. Katie Hall told CNN, discussing "resonance" technology. WiTricity is currently perfecting its specially designed resonators to efficiently dealing nation over longitudinal distances over the magnetised near-field.

Genuinely cordless freedom capital that extant gathering lamps, computers, televisions and gamy consoles would powerfulness up without the poverty to be plugged into protect outlets. Grouping would no thirster hold to illustration out adroit construction to fell the wires on their housing diversion system falsification. "Wireless galvanising power-imagine no more… it's here!," says WiTricity on its circle parcel.

"The melody of eliminating cables would allot us to redesign things in construction that we harbor't yet content of, that's right going to excrete our devices and everything that we interact with, that untold statesman businesslike, many useful and maybe flat yield form new functionality," said Explorer.

WiTricity's goal is to rid the incoming of replaceable batteries as comfortably as trousers. A time in wireless electricity technology could support to form scrutiny devices and industrialized systems many tried.

The team of physicists out of MIT behindhand WiTricity was led by Academic Marin Soljacic and developed the new theory for quality channel in 2005. The results of their findings were published in the book, Ability on July 6, 2007. "Using self-resonant coils in a strongly connected regime, we experimentally demonstrated prompt nonradiative knowledge transport over distances up to 8 nowadays the length of the coils. We were healthy to transaction 60 poet with ?40% efficiency over distances in unnecessary of 2 meters," said the unit

Change Your Driving Style to Conserve Gasoline

It seems as if the monolithic growth in gas prices over the live few life somebody had drivers everywhere disagreeable to play meaning of it all.  Why are the prices so altitudinous?  What can we do to economise a bit of money at the gas shoe?  While the premier proposal is not so rich to state, we eff quite a bit of examine ourselves over the position one.  After all, there are a find of relatively prosperous ways that we can economise gas and hence, change of supply t.b. when they decide what category of swing tool they module bed.  In ago age, that may mortal been a utterly rational objective, but with the gas prices feat to be so sharp, we moldiness all believe roughly how we can shrink our gas exercise.  After all, it is exploit harder and harder to be able to afford haunt fill-ups at the gas facility!  What follows are a few pretty essential structure that you can locomote your swing call to a statesman furnish timesaving one.

One fault that more drivers make is accelerating too often.  If you pay aid, you give observance that the vast majority of drivers accelerate nigh all the dimension.  It does not concern whether they are 50 feet from a red burn or a turn that they will score to adagio low for, they faculty sustain to bonk their organ on the gas faction up until they mortal to coppice.  This is a mistake for a Position of all, it makes no sentience to movement up towards a red white that you testament love to quit for in a unforbearing interval.  Instead, why not see your organ off the gas and seacoast a bit?  This gift not exclusive yield you to drop your brakes, but if the ill a locomote future up shortly, there is also no pauperization to intensify correct up until the point where you staleness lag.  Why do so, when you faculty then bed to copse aggressively in condition to safely hit your transform?  Instead, when you hit a boon indifference to your travel,

{Finally, try not to gate behindhand added drivers, and counter futurity stops or having to slow mastered.  If you allot yourself a superb amount of distance between yourself and the car(s) in strawman of you, you can see whether fill are fixing or turn with untold writer attention, which allows you to seacoast a bit kinda than having to dance on your brake.  Again, you're only symptom gas if you hurrying up to journey the car in foremost of yours' side bumper.  This is unneeded and can also be the movement of an happening!

These subtle tweaks to your dynamic style won't outgo you any period, and instrument drop you a lot of gas and assume and drop on your car.  Also, if you push lower aggressively, you instrument conglomerate little traffic tickets and accidents, which can outlay you way more money than gas e'er did!

Animals threatened with extinction

Are the types of animals and plants that face extinction . Scientists estimate that more than 8,300 plant species and 7,200 animal species on the planet are threatened with extinction and there is a majority of these species in the tropics and developing countries . There are thousands more die each year before scientists discovered that life . Extinction (Extinction) is a natural process during a march Alttorkadd evolved species disappeared slowly through geologic time as a result of climate changes and their inability to adapt to the relations of competition and predation . But since the beginning of the seventeenth century the rate of extinction has increased significantly due to the increase in the number of the world's population and human consumption of natural resources. Currently most of the citizens are changing more quickly than you can cope with most of the species through a process of evolution or natural selection . The current global extinction rate is greater than the natural extinction rate is worrying . Many biologists believe that we are in the midst of the largest mass extinction (Mass extinction) since the extinction of the dinosaurs 65 million years ago .

The size of the problem

Scientists estimate that the world loses between fifty thousand and a hundred thousand species of creatures every year has been a life scientists said that the rate of extinction of species is nearly twice what they were to go by the estimates of experts just four years . As pointed out by one environmental reports that the rate of decline in the species that did not happen in the land since the sixty-five million years ago , while the extinct dinosaurs and at this pace , we may be approaching extinction mass similar to what happened before and if you did not stop the deterioration of the current happening in the environment, the world will lose forever about fifty-five percent of the objects during a period ranging between fifty and a hundred years from now, I have already got in the past, the pace of similar losses in biodiversity , and resulted from such disasters disastrous effects reflected on the species that escaped from extinction. Over the next thirty years , scientists predict the extinction of nearly a quarter of known mammals and ten varieties of birds recorded as a result of climate change and the steady loss in their natural habitat . Also expect that a large number of insects, spiders and worms also oversees the extinction . When extinct varieties of objects , it leaves a gap in the eco-system , and possibly affect our environment and our consciousness . But that's not all , every object extinct , takes with him a wealth of information . When the last person to die in the class of objects , we lose all information about the adjustment processes that have accumulated over millions of years . It would be negligent of us adults that we allow the loss of this information

Facts and Figures
5.3 billion is the number of years of evolution to get to the current biodiversity
13-14 million is the total number of species which are estimated to exist
12-13 % is the percentage of the species studied
816 is the number of races that record extinction during the last five centuries of human activities Bmfol
1 of 4 is the ratio of mammal species that face extinction in the near future
1 of 7 is the ratio of plant species that are in danger of extinction in the near future
1 of 8 is the ratio of bird species face extinction in the near future
More than 200 billion U.S. dollars is the estimated value of international trade annually in the field of wildlife .

Reasons

Habitat destruction

There are many reasons that lead to the extinction of species threatened with extinction or make them , but the main reason is habitat destruction (Habitat Destruction) due to human activities . During the evolution of the species most adapted to live in the home or environment to meet the specific needs necessary for survival . Without this habitat of these species will not be able to live or stay . When the destruction of these habitats can not then these species continue to live in the same environment . There is a reason no less important than habitat destruction , a fragmentation of these habitats to small areas and isolated from each other , which leads to a disconnect between the plant and animal species remaining on these parts , which reduces the genetic diversity (Genetic diversity) and makes them less able to adapt to the environment and with changes climate and are thus vulnerable to extinction dramatically . There are many reasons that eliminate or fragmented habitats , including: pollution
Drying the wet land
Conversion of forest land to the pastoralist areas
Destruction of coral reefs
Construction of roads and dams
Build cities and residential areas

Trade kinds of wildlife

It is estimated that the annual return for the trade of wildlife species up to billions of dollars , and that this trade include hundreds of millions of species of plants and animals . And characterized this trade diversity and it stretches from animals and plants to various kinds of side products derived from them , including food products, leather and wooden musical instruments , antiques and tourist medicines . This trade has begun to emerge since the beginning of the seventeenth century and led to the extinction of many species are threatened with extinction or make them . For example, industries based on the whales, which they are hunting whales for their meat and oil is led to make many kinds of whales on the brink of extinction . The African black rhinoceros also seriously endangered due to hunting for horns, which is used as a medicine and tonic .
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The introduction of new species into the environment

The introduction of a species to new environmental system (Invasion by nonnative Species) cause many types of damage inherent in this ecosystem . May enter a kind of foreign intruder or to an ecosystem that accidentally or intentionally and can compete with fungal species already in the ecosystem or associated with predation relations . It may not have the plants and animals fungal no way to defend against invaders , and who may spend on these types or detract number dramatically . These destructive effects are often irreversible and often there is no way to prevent the damage from spreading.

Environmental Pollution

Environmental Pollution Pollution is another factor important cause of extinction . Toxic chemicals , especially chlorine compounds and materials of fertilizers and pesticides , such as ( the DDT) has become concentrated in food chains . The effect of these materials is greatest in the species near the top of the food pyramid . Water pollution and rising water temperature is an important factor also has spent many types of fish in many of the citizen. Water pollution oil also destroys the birds , fish and mammals . The oil can cover the bottom of the ocean for many years . It is also known that acid rain resulting from excessive toxicity to the air caused the death of neighborhoods in freshwater lakes and the destruction of vast tracts of forest land .
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Efforts to keep the species from extinction ?

Laboratory

Established in the UK for the tissue bank to store genetic material for thousands of endangered animals . The Bank will , which will be called " Noah's Ark frozen" , maintaining the " Blades of life" for these animals until after their extinction . This will enable future generations of scientists to understand the creatures that have become extinct a long time ago , and also help in future programs to keep animals that are threatened with extinction . This project enjoys the support of both the Natural History Museum and the Zoological Society of London and the University of Nottingham . Stages of the project Noah's Ark frozen : • takes scientists insects complete or small samples of animal tissue so as not life-threatening can be frozen tissue for safekeeping • DNA extraction from tissue samples , both after taking the sample directly or after freezing • can use the DNA for research purposes , which may lead one day, to clone objects extinct • send some DNA samples to other laboratories as a deposit against damage or loss • can be frozen DNA is used for the period may extend for thousands of years and the project aims " Noah's Ark frozen" to store a copy " backup " of the genetic code for many of the objects before extinction . The genetic codes will be stored in this database frozen , can be referenced in the future for the purpose of knowledge. In practice , this will require Daba pursuant to extract tissue samples from objects that are threatened with extinction . With the large-sized animals , it includes taking small pieces of animal skin while undergoing anesthesia . As with small organisms such as insects , it requires it to keep the entire organism . And then will be transferred to the plant tissue samples frozen Noah's Ark ( which will be distributed to a number of them in different parts of the globe ) and stored at extremely low temperatures . If all goes as planned , the samples RNA DNA)) , which contains the genetic code may remain intact for tens of thousands of years or more . Scientists say one of the supervisors of the project, " It is well known that the ( DNA er ) lasts a hundred thousand a year when the subject of conservation in nature. But under ideal storage conditions may be able to preserve the samples for a period longer than that . " The horse will be the Yellow Sea and Addax convex centuries and snails Bartola first objects in danger of extinction intervention frozen Noah's Ark project , at a cost of £ 200 for a single class . The project hopes to be able to store samples of thousands of varieties of other objects , ranging from mammals , birds, reptiles and even insects . Priority will be given to the objects that are threatened with extinction within the next five years . Organizers of the project was also keen to point out that it will not be limited to pets and domesticated . The main goal at this time for " Bank of genetic information " that is sure to keep a record of the genetic codes of the extinct creatures . And will be used in the interest of future generations . Said one of the organizers of the project , " This project is an essential tool has been able to study RNA sequences (DNA) of the extinct animals in the future . " "If the project was frozen Noah's Ark is located at the beginning of the twentieth century we were able to study animals such as the Tasmanian tiger and provide us with valuable information about the genetic relationships and evolution. " No one knows where the ship will dock Noah frozen in the end , but while locked Berhevha precious swirl future , the possibilities seem exciting .

Nature Reserves

And geographic regions are believed her government protection and support . Began to appear with the early twentieth century and are of great importance in the preservation of species and biodiversity. It was Yellowstone National Park in the United States of America 's first national park in the world. Today, there are around the world , rural areas set aside for wildlife Kmahmyat . Plants and animals in these areas are protected as much as possible from humans snipers and collectors , are also prohibited from investors and construction companies in which the construction of buildings . Some of these vast reserves includes thousands of square kilometers , and others to exceed small parcels of land not Ttalha hands after urban development .

CITES

CITES (CITES) is an abbreviation for the name of prolonged : the Convention on International Trade in animals and plants threatened with extinction (Convention on International Trade in Endangered Species of Wild Fauna and Flora) which is about an international agreement between governments , and aims to put the safeguards necessary to prevent the threat of international trade in these types of life and survival. At the time that crystallized the first ideas of the Convention in the sixties , it was the international debate about the regulation of trade in wildlife species in order to maintain a relatively new phenomenon , however hindsight it was the need for the Convention intuitive . It is estimated that the annual return for the trade of wildlife species up to billions of dollars , and that this trade include hundreds of millions of species of plants and animals . And characterized this trade diversity and it stretches from animals and plants to various kinds of side products derived from them , including food products, leather and musical instruments and wooden artifacts and tourist medicines .. Given the high rates of trade in certain animal and plant species and exploitation , as well as other factors, including the loss of and other natural habitat , it is possible that all of these reasons lead to a decline in large numbers and even the threat of extinction of some of them . Although most of the species that is where the trade is not endangered, but the existence of an agreement to ensure the continuation of this trade is vital in order to protect these natural resources in the future . As the trade in plants and animals are across the border between countries in nature , the special efforts organized requires international cooperation in order to ensure that the exposure of certain types where over-exploitation .. and it came the Convention on the ((CITES expressing this spirit of cooperation , they are today offering varying degrees the protection of more than 30 thousand species of plants and animals ( about 5,000 animal species and 25,000 species of plants ) whether trafficking as a species live or were fled or herbs dried . technically it has formulated a draft of CITES, as a result of the adoption of a resolution in in 1963 to members of the International Union for the Protection of the Environment IUCN, then agree on the text of the agreement at the end of it inside the meeting included representatives of 80 countries, was held in March 3, 1973 in Washington DC , and the Convention entered into force with effect from the first in July 1975 . and CITES is an international agreement adopted by states voluntarily , and although the agreement is legally binding for States Parties ( signatory states ) , in other words, commits the countries concerned to apply , but it does not replace the local national laws relating to these topics. Instead, the Convention provides a framework that must be respected by all parties that they must adopt local legislation and providing the necessary guarantees to ensure the application of the CITES Convention at the national level or national level. Since he entered the CITES Convention to take effect for years , did not happen that displays the type of species to extinction because of trade , and considering the offer agreement to protect those species , and enjoys agreement on membership of 162 countries , making it the largest international convention ever to protect life fungal . The working principle of CITES, the modus operandi of CITES are in accordance with international trade subject to a certain degree of control in certain types of vital selection . These require rationing to control all operations of import and export and re- export to the sheer diversity of those species covered by the provisions of CITES, through a licensing system . It is worth mentioning that there are internationally known global organizations working to ensure the work of CITES at the level of the world and Interpol , the World Customs Organization , the United Nations Environment Programme, and other non- governmental organizations. CITES is also working directly with a certain number of conventions , including the Convention on Biological Diversity CBD, the Basel Convention BASEL, Ramsar Ramsar, CMS CMS, the International Convention for the Regulation of Whaling . The affects of this joint cooperation aspects of work such as training to work in the common customs , and to reconcile the legislation . The species covered by CITES, was prepared by the lists were included in three of the Annexes to the Convention , according to the degree of protection required by any kind : • Annex I: includes endangered species , are not allowed to exercise the trade in these species , except in exceptional circumstances .. It includes about 600 the type of animal , and nearly 300 plant species . • Appendix II includes species not necessarily threatened with extinction , but it must impose restrictions on trade in order to avoid inappropriate use of survival .. and has more than 1,400 animal species and more than 22,000 species of plants . • Appendix III includes species are protected in a particular country , but it requires the assistance of other States Parties to CITES in controlling the trade in this species .. and includes about 270 species animal and 7 types of plants. , Where some countries may ask to have this product threatened then extinction , but it exists in other countries .

Syria

According to the Statistical Office of the United Nations , there are 26 species endangered in Syria, 17 from the animal kingdom and 9 of the plant kingdom . Syria has taken several measures to preserve endangered animals was the most recent actions taken to protect the bird " bald ibis ," which was discovered in Palmyra desert area of extinction . This bird was discovered by Syrian citizens by accident while on a survey and monitor the birds Palmyra area and biodiversity within the project of reviving pastures. Number of bald ibis birds in the world , ranging from 200-300 birds present in Morocco , Turkey, Syria , Yemen and Senegal . Found five of them in Syria and believes that these birds are the only five remaining in the world still kept the historic migration path line where you start to come to destroy Syria in February to July each year . And has been issued in Syria, many of the laws and regulations that concerned with the preservation of the environment and biodiversity and protect the species from extinction was the most important: the content of the legislation general type of legislation regulating fishing aquaculture 1964 legislative decree (30) regulates land use, forest 1966 Law No. 7 regulate hunting of wild animals The birds Allammloch 1970 legislative decree No. 156 regulating the import and export of livestock 1979 Law No. 247 to prevent hunting for five years in 1994 resolution No. 40 regulates the exploitation of forestry 1994 Law No. 87 regulates the use rights Balahtab timber 1994 resolution 38 / v extension to prevent hunting for five years in 1999 resolution ? ? ? ?

Nature Reserves

Nineties period saw the publication of numerous decisions that are many sites as nature reserves or wild aquatic ( marine and freshwater ) , where such decisions deprive all human activities subversive of sites and activities were limited to scientific purposes only . The most important of these reserves :
Protected fir and cedar : State: Latakia Area: 1350 hectares with a proposal to expand to 20,000 hectares of the project , which was launched during the implementation .
Mount protected Abdul Aziz : State: Al-Hasakah . Area: 4220 hectares .
Forest Reserve Alverlq : State: Latakia . Area declared : 1500 hectares .
Ras simple Governorate: Lattakia . Area: 3,000 hectares .
Or protected birds ( protected beach freely) . Province: Latakia . Area: 1000 hectares
In spite of national efforts to protect biodiversity , but that the establishment of nature reserves in the modern sense , comprehensive and that is by participation of local people in the implementation of protection is still in its infancy .
Some types of endangered animals

There are more than 800 species of animals threatened with extinction and extinction and there are associations sequence is maintained and need material and moral support for the success of Bmqsdha .
Of these animals : -
Assam hog wild there is only now in the province of Assam , India , which is no small numbers and faces the courtyard
Animal lemurs who live it are currently 30 animals on the island of Madagascar and Nothingness him anywhere else in the world
Forest turtle , which did not remain only in 1000 only turtle living in the slopes of the Andes in Colombia after the acceleration of deforestation and the destruction of their environment in which they live
Toad found only on the island of Mallorca , it is usually the male animal carrying fertilized eggs on its back until they hatch , and the causes of diseases and the extinction assault on the environment in which they live
Little did Albrkit stupidly leaving only 200 birds in the southwestern island of Mauritius and that because of the loss of its food , which share the island mice in his food and to pay starvation
Flat -tailed bats , creatures that have caused civilization , tourism and human assault on the environment for normal living , which helped in the near extinction , it was now only left him only 100 giant pandas

How to make compost

The fertilization process is excellent for improving soil quality and prevent it from erosion . It is through fertilization , re- organic materials , consumed by plants , to the soil - and this would improve the soil structure . The organic material is that bind soil particles together and prevent them from erosion . If we add compost to sandy soil to become capable of storing larger quantities of water and become rich in nutrients . And of course we all know that sand does not store water well and is poor in nutrients , and this justifies our inability to planting vegetables and most of the trees in the sand ( or in other words, soils dominated by sand) . But if we add compost to the clay soil ( sand that are poor and rich mud - and thus poorly drained and heavy ), it will help to increase the distances between the particles , making them able to drain the excess water that you drink . Improving the quality of the soil affects positively on the plants , and the good plants to prevent soil erosion .

The materials used for making fertilizer


Any material originating from plants can be used to make compost . Valawrac land or green , grass, weeds, food scraps and sawdust , and a small timber , and animal dung , and newspapers are all good materials to use. The hovering , and bones , and fatty foods , do not recommend that you use it to attract rats and snakes .





Turn these materials after that we collect in the bowl to the simple organic materials , and bacteria play an important role in achieving this matter . Bacteria are working on an analysis of the plants and their waste - that we have mentioned - to the nutrients available for use by the cultivated plants . Be those materials containing a certain percentage of carbon and nitrogen. Vencarh wood , for example , has a ratio of 500 parts of carbon for every one part of nitrogen. The food waste Fathtoa on the proportion of 15 parts of carbon for every one part of nitrogen. It is important in this is that we know that there is a material rich in nitrogen and other carbon-rich . The bacteria work well if it were a mixture ( materials that we have mentioned ) contain a 30 portion of the carbon for every one part of nitrogen (30 : 1) , and this can be achieved by mixing green materials ( rich in nitrogen ) with material structure ( carbon-rich ) .



- Green materials , or materials rich in nitrogen are:
Vegetables , and food scraps , and weeds , egg shells , and animal dung ...

- Structure of materials , or carbon-rich materials are:
Tree leaves , straw, plain paper , small pieces of wood , sawdust ...



How to prepare a pot -making fertilizer


The vessel , which we will use to make compost made ​​of iron clamp . As shown in the drawing , it is a length of 90 Smontmitr and height of 90 centimeters , too. The container can be made manually or buy it from the store . If ye making such a pot or buy one like it , you can use a bowl made ​​of wood or plastic - provided that the walls are perforated to allow air to enter , and to be mentioned in the same size - or larger if needed.



Practical steps for the success of the process of making compost



First in the kitchen
Try to keep the pot put the leftover food , and tried to separate each layer paper newspaper in order to facilitate the process of cleaning the bowl and dump the contents .

Do not cover the pot because the substances found inside Stakhtmr and become fetid .

You can put the vegetables , and food waste , cans and paper , and eggshells (after grinding ) , and any other organic material . But you should not put meat, fatty substances , and products made ​​from milk ( milk , cheese, yoghurt ) , and egg white , and bones.

Whenever we put a little bowl filled with paper and newspaper in order to prevent the emission of odor, in order to separate the layers of the vessel .

When the container is full extricate it to the place where there are pot fertilization basic and unload the contents . After emptied , clean it and put in his own land newsprint and then bring him back to the kitchen to Nmlih again .

Secondly, when the primary receptacle
Keep primary receptacle in a shady place outside the home. The best that we put it on the dirt in order to absorb the material that may fall out of the bowl.

Keep in the bottom of the container layer of twigs and leaves of trees . Better to be strong so that this layer does not break down when we start Bmlye bowl. The goal of the existence of this layer is the center of the bowl ventilation .

The best way to fill the pot is split content aligned to the layers on top of each - as shown in the first drawing . Class that is made ​​up of green materials , followed by a layer material structure and so on ... There is wisdom behind this method , but we can not explain the whole , but in brief this method allows ventilation of the material in the vessel and assist in the discharge of water from the vessel - which is usually Alohjae stored in the leaves and foods ...

When you begin to mobilize the vessel lay material first and then build a structure above the layers form in which we have mentioned above . When the container is full , better to be the last layer structure also . As shown in the drawing , layered structure be larger than the layers of green .

The last step is optional . When Nmlye pot, we upside down in his heart all the while without dropping the material inside , and this helps to speed up the process of fermentation of materials and converts them into fertilizer .




Resulting from the use of compost mixture



In order to become a brewing materials and ready-to- use take an indefinite period of time. There are many factors affect the speed of fermentation materials : including the weather , and the size of the pot , and the materials used , and the number of times the heart of the bowl. Usually, brewing materials at the bottom of the bowl first. Even the upper classes were delayed fermentation recommend the heart of the vessel , in order to make it at the bottom . After fermentation , the content of the container becomes ready for use.


Usually become material in the vessel ready for use when :

Becomes the size of a third of the original size.

It becomes brown in color .

Become fragmented .

Become her smell like the smell of dirt or earth .



Compost is a medicine poor soil with organic matter and nutrients . We use in the fields to fertilize trees and vegetables. ( God did not create things in vain .. even animal dung and waste of food , and the leaves of trees contribute to securing our food. Whatever we counted a blessing it is much more than we imagine . ) .. Of course be stated in the articles of reminder yes God is not translated ! ! !



Errors that may be contained with us and how to fix it


In some cases , including conducting Alraih not go wrong , and mixed piggledy . Here are some errors that may soak or suddenly appear when we make compost , and solutions to them .


This image has been resized . Click this bar to view the full image . The original image is 844x148.



The idea of ​​positive
If immersion compost which we got in a bowl of water for a week the water will become liquid fertilizer (called a nutrient solution ) is used for the same purpose , which use it for fertilizer normal . The difference here is the ease of fertilization and do not need to grub or hoeing the soil in order to Nsmd plants. Read about how to prepare nutritious organic solution .


Encourage your surroundings on the use of organic fertilizers
Here are some ways you can follow to promote the command:

Make a compost - the way in which we have mentioned - several times in order to become an expert about it . Then Cultivate some plants in containers or in the garden , using this compost and seen them ( neighbors , relatives and friends ) results through crop Thsdh . Also tell them about the advantages of this compost and how it is made 100% by hand at home , it does not cost us cheesed off , but it turns materials that we previously we consider waste materials to be used and take advantage of them.

If you became an expert thing (say a year later ) and knowing the problems and solutions , to introduce the idea to the school or university, which taught them , and in Lebanon, there are many schools of Islamic and Christian concerned with the issue of waste recycling and composting organic , where you play pupils instrumental in the process. There are successful experiences in Egypt benefited from the process of converting waste into organic fertilizer and has become one of the pioneers of exporters of fertilizer in the Arab world

How the glass industry

This article is about the material. For other uses, see ).

Studio glass by Tyler Hopkins, demonstrating many of the essential properties of glass

Glass is an amorphous (non-crystalline) solid material that exhibits a glass transition, which is the reversible transition in amorphous materials (or in amorphous regions within semicrystalline materials) from a hard and relatively brittle state into a molten or rubber-like state. Glasses are typically brittleand can be optically transparent. The most familiar type of glass is soda-lime glass, which is composed of about 75% silicon dioxide (SiO₂), sodium oxide (Na₂O) from soda ash, lime (CaO), and several minor additives. The term glass is often used to refer only to this specific use.

Silicate glass generally has the property of being transparent. Because of this, it has a great many applications. One of its primary uses is as a building material, traditionally as small panes set into window openings in walls, but in the 20th-century often as the major cladding material of many large buildings. Because glass can be formed or moulded into any shape, and also because it is a sterile product, it has been traditionally used for vessels:bowls, vases, bottles, jars and glasses. In its most solid forms it has also been used for paperweights, marbles, and beads. Glass is both reflective and refractive of light, and these qualities can be enhanced by cutting and polishing in order to make optical lenses, prisms and fine glassware. Glass can be coloured by the addition of metallic salts, and can also be painted. These qualities have led to the extensive use of glass in the manufacturing of art objects and in particular, stained glass windows. Although brittle, glass is extremely durable, and many examples of glass fragments exist from early glass-making cultures.

In science, however, the term glass is defined in a broader sense, encompassing every solid that possesses a non-crystalline (i.e. amorphous) structure and exhibits a glass transition when heated towards the liquid state. These sorts of glasses can be made of quite different kinds of materials: metallicalloys, ionic melts, aqueous solutions, molecular liquids, and polymers. For many applications (bottles, eyewear) polymer glasses (acrylic glass,polycarbonate, polyethylene terephthalate) are a lighter alternative to traditional silica glasses.

Silicate glass

Silica (the chemical compound SiO₂) is a common fundamental constituent of glass. In nature, vitrification of quartz occurs when lightning strikes sand, forming hollow, branching rootlike structures called fulgurite.

While fused quartz (primarily composed of SiO₂) is used for some special applications, it is not very common due to its high glass transition temperature of over 1200 °C (2192 °F).^[1] Normally, other substances are added to simplify processing. One is sodium carbonate (Na₂CO₃, "soda"), which lowers the glass transition temperature. However, the soda makes the glass water soluble, which is usually undesirable, so lime (calcium oxide [CaO], generally obtained from limestone), some magnesium oxide (MgO) and aluminium oxide (Al₂O₃) are added to provide for a better chemical durability. The resulting glass contains about 70 to 74% silica by weight and is called a soda-lime glass.^[2] Soda-lime glasses account for about 90% of manufactured glass.

Most common glass contains other ingredients added to change its properties. Lead glass or flint glass is more 'brilliant' because the increased refractive index causes noticeably more specular reflection and increased optical dispersion. Adding barium also increases the refractive index. Thorium oxide gives glass a high refractive index and low dispersion and was formerly used in producing high-quality lenses, but due to its radioactivity has been replaced by lanthanum oxide in modern eyeglasses.^{[citation needed]} Iron can be incorporated into glass to absorb infrared energy, for example in heat absorbing filters for movie projectors, while cerium(IV) oxide can be used for glass that absorbs UV wavelengths.^[3]

The following is a list of the more common types of silicate glasses, and their ingredients, properties, and applications:

1. Fused silica glass, vitreous silica glass: silica (SiO₂). Has very low thermal expansion, is very hard and resists high temperatures (1000–1500 °C). It is also the most resistant against weathering (alkali ions leaching out of the glass, while staining it). It is used for high temperature applications such as furnace tubes, melting crucibles, etc.
2. Soda-lime-silica glass, window glass: silica 72% + sodium oxide (Na₂O) 14.2% + magnesia (MgO) 2.5% + lime (CaO) 10.0% + alumina (Al₂O₃) 0.6%. Is transparent, easily formed and most suitable for window glass. It has a high thermal expansion and poor resistance to heat (500–600 °C). Used for windows, containers, light bulbs, tableware.
3. Sodium borosilicate glass, Pyrex: silica 81% + boric oxide (B₂O₃) 12% + soda (Na₂O) 4.5% + alumina (Al₂O₃) 2.0%. Stands heat expansion much better than window glass. Used for chemical glassware, cooking glass, car head lamps, etc. Borosilicate glasses (e.g. Pyrex) have as main constituents silica and boron oxide. They have fairly low coefficients of thermal expansion (7740 Pyrex CTE is 3.25×10^–6/°C^[4] as compared to about 9×10⁻⁶/°C for a typical soda-lime glass^[5]), making them more dimensionally stable. The lower CTE also makes them less subject to stress caused by thermal expansion, thus less vulnerable to cracking from thermal shock. They are commonly used for reagent bottles, optical components and household cookware.
4. Lead-oxide glass, crystal glass: silica 59% + soda (Na₂O) 2.0% + lead oxide (PbO) 25% + potassium oxide (K₂O) 12% + alumina 0.4% + zinc oxide (ZnO) 1.5%. Has a high refractive index, making the look of glassware more brilliant (crystal glass). It also has a high elasticity, making glassware 'ring'. It is also more workable in the factory, but cannot stand heating very well.
5. Aluminosilicate glass: silica 57% + alumina 16% + boric oxide (B₂O₃) 4.0% + barium oxide (BaO) 6.0% + magnesia 7.0% + lime 10%. Extensively used for fiberglass, used for making glass-reinforced plastics (boats, fishing rods, etc.). Also for halogen bulb glass.
6. Oxide glass: alumina 90% + germanium oxide (GeO₂) 10%. Extremely clear glass, used for fiber-optic wave guides in communication networks. Light loses only 5% of its intensity through 1 km of glass fiber.^[6]

Another common glass ingredient is "cullet" (recycled glass). The recycled glass saves on raw materials and energy; however, impurities in the cullet can lead to product and equipment failure. Fining agents such as sodium sulfate, sodium chloride, or antimony oxide may be added to reduce the number of air bubbles in the glass mixture.^[2] Glass batch calculation is the method by which the correct raw material mixture is determined to achieve the desired glass composition.

Physical properties

Optical properties

Glass is in widespread use largely due to the production of glass compositions that are transparent to visible wavelengths of light. In contrast, polycrystalline materials do not in general transmit visible light.^[7] The individual crystallites may be transparent, but their facets (grain boundaries) reflect or scatter light resulting in diffuse reflection. Glass does not contain the internal subdivisions associated with grain boundaries in polycrystals and hence does not scatter light in the same manner as a polycrystalline material. The surface of a glass is often smooth since during glass formation the molecules of the supercooled liquid are not forced to dispose in rigid crystal geometries and can follow surface tension, which imposes a microscopically smooth surface. These properties, which give glass its clearness, can be retained even if glass is partially light-absorbing—i.e., colored.^[8]

Glass has the ability to refract, reflect, and transmit light following geometrical optics, without scattering it. It is used in the manufacture of lenses and windows. Common glass has a refraction index around 1.5. According to Fresnel equations, the reflectivity of a sheet of glass is about 4% per surface (at normal incidence in air), and the transmissivity of one element (two surfaces) is about 90%. Glass also finds application in optoelectronics—e.g., for light-transmitting optical fibers.

Other properties

In the process of manufacture, silicate glass can be poured, formed, extruded and moulded into forms ranging from flat sheets to highly intricate shapes. The finished product is brittle and will fracture, unless laminated or specially treated, but is extremely durable under most conditions. It erodes very slowly and can withstand the action of water. It is resilient to chemical attack and is an ideal material for the manufacture of containers for foodstuffs and most chemicals.

Contemporary production

Main articles: Glass production, Float glass, and Glazier

Following the glass batch preparation and mixing, the raw materials are transported to the furnace. Soda-lime glass for mass production is melted in gas fired units. Smaller scale furnaces for specialty glasses include electric melters, pot furnaces, and day tanks.^[2] After melting, homogenization and refining (removal of bubbles), the glass is formed. Flat glass for windows and similar applications is formed by the float glass process, developed between 1953 and 1957 by Sir Alastair Pilkington and Kenneth Bickerstaff of the UK's Pilkington Brothers, who created a continuous ribbon of glass using a molten tin bath on which the molten glass flows unhindered under the influence of gravity. The top surface of the glass is subjected to nitrogen under pressure to obtain a polished finish.^[9] Container glass for common bottles and jars is formed by blowing and pressing methods. Further glass forming techniques are summarized in the table Glass forming techniques.

Once the desired form is obtained, glass is usually annealed for the removal of stresses. Surface treatments, coatings or lamination may follow to improve the chemical durability (glass container coatings, glass container internal treatment), strength (toughened glass, bulletproof glass, windshields), or optical properties (insulated glazing, anti-reflective coating)

Color

Main article: Glass coloring and color marking

Color in glass may be obtained by addition of electrically charged ions (or color centers) that are homogeneously distributed, and by precipitation of finely dispersed particles (such as inphotochromic glasses).^[10] Ordinary soda-lime glass appears colorless to the naked eye when it is thin, although iron(II) oxide (FeO) impurities of up to 0.1 wt%^[11] produce a green tint, which can be viewed in thick pieces or with the aid of scientific instruments. Further FeO and Cr₂O₃ additions may be used for the production of green bottles. Sulfur, together with carbon and iron salts, is used to form iron polysulfides and produce amber glass ranging from yellowish to almost black.^[12] A glass melt can also acquire an amber color from a reducing combustion atmosphere.Manganese dioxide can be added in small amounts to remove the green tint given by iron(II) oxide. When used in art glass or studio glass glass is colored using closely guarded recipes that involve specific combinations of metal oxides, melting temperatures and 'cook' times. Most colored glass used in the art market is manufactured in volume by vendors who serve this market although there are some glass makers with the ability to make their own color from raw materials.

History of silicate glass

Main article: History of glass

See also: Architectural glass and Stained glass

The term glass developed in the late Roman Empire. It was in the Roman glassmaking center at Trier, now in modern Germany, that the late-Latin term glesum originated, probably from aGermanic word for a transparent, lustrous substance.^[13]

Roman Cage Cup from the 4th century CE

Naturally occurring glass, especially the volcanic glass obsidian, has been used by many Stone Age societies across the globe for the production of sharp cutting tools and, due to its limited source areas, was extensively traded. But in general, archaeological evidence suggests that the first true glass was made in coastal north Syria, Mesopotamia or Ancient Egypt.^[14] The earliest known glass objects, of the mid third millennium BCE, were beads, perhaps initially created as accidental by-products of metal-working (slags) or during the production of faience, a pre-glass vitreous material made by a process similar to glazing.^[15]

Glass remained a luxury material, and the disasters that overtook Late Bronze Age civilizations seem to have brought glass-making to a halt. Indigenous development of glass technology in South Asia may have begun in 1730 BCE.^[16] In ancient China, though, glassmaking seems to have a late start, compared to ceramics and metal work. In the Roman Empire, glass objects have been recovered across the Roman Empire in domestic, industrial and funerary contexts.

Bohemian flashed and engraved ruby glass (19th-century)

Glass was used extensively during the Middle Ages. Anglo-Saxon glass has been found across England during archaeological excavations of both settlement and cemetery sites. Glass in the Anglo-Saxon period was used in the manufacture of a range of objects including vessels, beads, windows and was also used in jewellery. From the 10th-century onwards, glass was employed in stained glass windows of churches and cathedrals, with famous examples at Chartres Cathedral and the Basilica of Saint Denis. By the 14th-century, architects were designing buildings with walls of stained glass such as Sainte-Chapelle, Paris, (1203-1248)^[17] and the East end of Gloucester Cathedral.^[18] Stained glass had a major revival with Gothic Revival architecture in the 19th-century. With the Renaissance, and a change in architectural style, the use of large stained glass windows became less prevalent. The use of domestic stained glass increased until it was general for every substantial house to have glass windows. These were initially of small panes leaded together, but with the changes in technology, glass could be manufactured relatively cheaply in increasingly larger sheets, leading to larger window panes, and, in the 20th-century, to much larger windows in ordinary domestic and commercial premises.

Studio glass by David Patchen. Multiple colors within a single object increases the difficulty of production, as each color has different chemical and physical properties when molten.

In the 20th-century, new types of glass such as laminated glass, reinforced glass and glass bricks have increased the use of glass as a building material and resulted in new applications of glass. Multi-storey buildings are frequently constructed withcurtain walls made almost entirely of glass. Similarly, laminated glass has been widely applied to vehicles for windscreens. While glass containers have always been used for storage and are valued for their hygienic properties, glass has been utilised increasingly in industry. Optical glass for spectacles has been in use since the late Middle Ages. The production of lenses has become increasingly proficient, aiding astronomers as well as having other application in medicine and science. Glass is also employed as the aperture cover in many solar energy systems.

From the 19th century, there was a revival in many ancient glass-making techniques including Cameo glass, achieved for the first time since the Roman Empire and initially mostly used for pieces in a neo-classical style. The Art Nouveau movement made great use of glass, with René Lalique, Émile Gallé, and Daum of Nancy producing colored vases and similar pieces, often in cameo glass, and also using lustre techniques. Louis Comfort Tiffany in America specialized in stained glass, both secular and religious, and his famous lamps. The early 20th-century saw the large-scale factory production of glass art by firms such as Waterfords and Lalique. From about 1960 onwards there have been an increasing number of small studios hand-producing glass artworks, and glass artists began to class themselves as in effect sculptors working in glass, and their works as part fine arts.

In the 21st century, scientists, observing the properties of ancient stained glass windows, in which suspended nanoparticles prevent UV light from causing chemical reactions that change image colors, are developing photographic techniques that use similar stained glass to capture true color images of Mars for the 2019 ESA Mars Rover mission

Chronology of advances in architectural glass

• 1226 – "Broad Sheet" first produced in Sussex
• 1330 – "Crown Glass" first produced in Rouen, France. "Broad Sheet" also produced. Both were also supplied for export
• 1620 – "Blown Plate" first produced in London. Used for mirrors and coach plates.
• 1678 – "Crown Glass" first produced in London. This process dominated until the 19th century
• 1843 – An early form of "Float Glass" invented by Henry Bessemer, pouring glass onto liquid tin. Expensive and not a commercial success.
• 1888 – "Machine Rolled" glass introduced allowing patterns to be introduced
• 1898 – "Wired Cast" glass invented by Pilkington for use where safety or security was an issue.
• 1959 – "Float Glass" launched in UK. Invented by Sir Alastair Pilkington

Other types of glass

New chemical glass compositions or new treatment techniques can be initially investigated in small-scale laboratory experiments. The raw materials for laboratory-scale glass melts are often different from those used in mass production because the cost factor has a low priority. In the laboratory mostly pure chemicals are used. Care must be taken that the raw materials have not reacted with moisture or other chemicals in the environment (such as alkali or alkaline earth metal oxides and hydroxides, or boron oxide), or that the impurities are quantified (loss on ignition).^[21]Evaporation losses during glass melting should be considered during the selection of the raw materials, e.g., sodium selenite may be preferred over easily evaporating SeO₂. Also, more readily reacting raw materials may be preferred over relatively inert ones, such as Al(OH)₃ over Al₂O₃. Usually, the melts are carried out in platinum crucibles to reduce contamination from the crucible material. Glass homogeneity is achieved by homogenizing the raw materials mixture (glass batch), by stirring the melt, and by crushing and re-melting the first melt. The obtained glass is usuallyannealed to prevent breakage during processing.^[21][22]

In order to make glass from materials with poor glass forming tendencies, novel techniques are used to increase cooling rate, or reduce crystal nucleation triggers. Examples of these techniques include aerodynamic levitation (cooling the melt whilst it floats on a gas stream), splat quenching (pressing the melt between two metal anvils) and roller quenching (pouring the melt through rollers).

Network glasses

Some glasses that do not include silica as a major constituent may have physico-chemical properties useful for their application in fiber optics and other specialized technical applications. These include fluoride glasses, aluminosilicates, phosphate glasses, borate glasses, and chalcogenide glasses.

There are three classes of components for oxide glasses: network formers, intermediates, and modifiers. The network formers (silicon, boron, germanium) form a highly cross-linked network of chemical bonds. The intermediates (titanium, aluminium, zirconium, beryllium, magnesium, zinc) can act as both network formers and modifiers, according to the glass composition. The modifiers (calcium, lead, lithium, sodium, potassium) alter the network structure; they are usually present as ions, compensated by nearby non-bridging oxygen atoms, bound by one covalent bond to the glass network and holding one negative charge to compensate for the positive ion nearby. Some elements can play multiple roles; e.g. lead can act both as a network former (Pb⁴⁺ replacing Si⁴⁺), or as a modifier.

The presence of non-bridging oxygens lowers the relative number of strong bonds in the material and disrupts the network, decreasing the viscosity of the melt and lowering the melting temperature.

The alkali metal ions are small and mobile; their presence in glass allows a degree of electrical conductivity, especially in molten state or at high temperature. Their mobility, however, decreases the chemical resistance of the glass, allowing leaching by water and facilitating corrosion. Alkaline earth ions, with their two positive charges and requirement for two non-bridging oxygen ions to compensate for their charge, are much less mobile themselves and also hinder diffusion of other ions, especially the alkalis. The most common commercial glasses contain both alkali and alkaline earth ions (usually sodium and calcium), for easier processing and satisfying corrosion resistance.^[24] Corrosion resistance of glass can be achieved by dealkalization, removal of the alkali ions from the glass surface by reaction with e.g. sulfur or fluorine compounds. Presence of alkaline metal ions has also detrimental effect to the loss tangent of the glass, and to its electrical resistance; glasses for electronics (sealing, vacuum tubes, lamps...) have to take this in account.

Addition of lead(II) oxide lowers melting point, lowers viscosity of the melt, and increases refractive index. Lead oxide also facilitates solubility of other metal oxides and therefore is used in colored glasses. The viscosity decrease of lead glass melt is very significant (roughly 100 times in comparison with soda glasses); this allows easier removal of bubbles and working at lower temperatures, hence its frequent use as an additive in vitreous enamels and glass solders. The high ionic radius of the Pb²⁺ ion renders it highly immobile in the matrix and hinders the movement of other ions; lead glasses therefore have high electrical resistance, about two orders of magnitude higher than soda-lime glass (10^8.5 vs 10^6.5 Ohm·cm, DC at 250 °C). For more details, see lead glass.^[25]

Addition of fluorine lowers the dielectric constant of glass. Fluorine is highly electronegative and attracts the electrons in the lattice, lowering the polarizability of the material. Such silicon dioxide-fluoride is used in manufacture of integrated circuits as an insulator. High levels of fluorine doping lead to formation of volatile SiF₂O and such glass is then thermally unstable. Stable layers were achieved with dielectric constant down to about 3.5–3.7

Amorphous metals

In the past, small batches of amorphous metals with high surface area configurations (ribbons, wires, films, etc.) have been produced through the implementation of extremely rapid rates of cooling. This was initially termed "splat cooling" by doctoral student W. Klement at Caltech, who showed that cooling rates on the order of millions of degrees per second is sufficient to impede the formation of crystals, and the metallic atoms become "locked into" a glassy state. Amorphous metal wires have been produced by sputtering molten metal onto a spinning metal disk. More recently a number of alloys have been produced in layers with thickness exceeding 1 millimeter. These are known as bulk metallic glasses (BMG). Liquidmetal Technologiessell a number of zirconium-based BMGs. Batches of amorphous steel have also been produced that demonstrate mechanical properties far exceeding those found in conventional steel alloys.^[27][28][29]

In 2004, NIST researchers presented evidence that an isotropic non-crystalline metallic phase (dubbed "q-glass") could be grown from the melt. This phase is the first phase, or "primary phase," to form in the Al-Fe-Si system during rapid cooling. Interestingly, experimental evidence indicates that this phase forms by a first-order transition. Transmission electron microscopy (TEM) images show that the q-glass nucleates from the melt as discrete particles, which grow spherically with a uniform growth rate in all directions. The diffraction pattern shows it to be an isotropic glassy phase. Yet there is a nucleation barrier, which implies an interfacial discontinuity (or internal surface) between the glass and the melt

Electrolytes

Electrolytes or molten salts are mixtures of different ions. In a mixture of three or more ionic species of dissimilar size and shape, crystallization can be so difficult that the liquid can easily be supercooled into a glass. The best studied example is Ca_0.4K_0.6(NO₃)_1.4.

Aqueous solutions

Some aqueous solutions can be supercooled into a glassy state, for instance LiCl:RH₂O in the composition range 4<R<8.

Molecular liquids

A molecular liquid is composed of molecules that do not form a covalent network but interact only through weak van der Waals forces or through transient hydrogen bonds. Many molecular liquids can be supercooled into a glass; some are excellent glass formers that normally do not crystallize.

A widely known example is sugar glass.

Under extremes of pressure and temperature solids may exhibit large structural and physical changes that can lead to polyamorphic phase transitions.^[32] In 2006 Italian scientists created an amorphous phase of carbon dioxide using extreme pressure. The substance was named amorphous carbonia(a-CO₂) and exhibits an atomic structure resembling that of silica

Colloidal glasses

Concentrated colloidal suspensions may exhibit a distinct glass transition as function of particle concentration or density

Glass-ceramics

Glass-ceramic materials share many properties with both non-crystalline glass and crystalline ceramics. They are formed as a glass, and then partially crystallized by heat treatment. For example, the microstructure of whiteware ceramics frequently contains both amorphous and crystalline phases. Crystalline grains are often embedded within a non-crystalline intergranular phase of grain boundaries. When applied to whiteware ceramics, vitreousmeans the material has an extremely low permeability to liquids, often but not always water, when determined by a specified test regime.^[37][38]

The term mainly refers to a mix of lithium and aluminosilicates that yields an array of materials with interesting thermomechanical properties. The most commercially important of these have the distinction of being impervious to thermal shock. Thus, glass-ceramics have become extremely useful for countertop cooking. The negative thermal expansion coefficient (CTE) of the crystalline ceramic phase can be balanced with the positive CTE of the glassy phase. At a certain point (~70% crystalline) the glass-ceramic has a net CTE near zero. This type of glass-ceramic exhibits excellent mechanical properties and can sustain repeated and quick temperature changes up to 1000 °C

Structure

Main article: Structure of liquids and glasses

As in other amorphous solids, the atomic structure of a glass lacks any long-range translational periodicity. However, due to chemical bonding characteristics glasses do possess a high degree of short-range order with respect to local atomic polyhedra.^[39]

The amorphous structure of glassy silica (SiO₂) in two dimensions. No long-range order is present, although there is local ordering with respect to the tetrahedralarrangement of oxygen (O) atoms around the silicon (Si) atoms.

Formation from a supercooled liquid[edit]

Main article: Glass transition

In physics, the standard definition of a glass (or vitreous solid) is a solid formed by rapid melt quenching.^{[40][41][42][43][44]} However, the term glass is often used to describe any amorphous solid that exhibits a glass transition temperature T_g. If the cooling is sufficiently rapid (relative to the characteristic crystallization time) then crystallization is prevented and instead the disordered atomic configuration of the supercooled liquid is frozen into the solid state at T_g. The tendency for a material to form a glass while quenched is called glass forming ability. This ability can be predicted by therigidity theory.^[45] Generally, the structure of a glass exists in a metastable state with respect to its crystalline form, although in certain circumstances, for example in atactic polymers, there is no crystalline analogue of the amorphous phase.^[46]

Some people consider glass to be a liquid due to its lack of a first-order phase transition^[47][48] where certain thermodynamic variables such as volume,entropy and enthalpy are discontinuous through the glass transition range. However, the glass transition may be described as analogous to a second-order phase transition where the intensive thermodynamic variables such as the thermal expansivity and heat capacity are discontinuous.^[49] Despite this, the equilibrium theory of phase transformations does not entirely hold for glass, and hence the glass transition cannot be classed as one of the classical equilibrium phase transformations in solids.^[43][44]

Glass is an amorphous solid. It exhibits an atomic structure close to that observed in the supercooled liquid phase but displays all the mechanical properties of a solid.^[47][50] The notion that glass flows to an appreciable extent over extended periods of time is not supported by empirical research or theoretical analysis (see viscosity of amorphous materials). Laboratory measurements of room temperature glass flow do show a motion consistent with a material viscosity on the order of 10¹⁷–10¹⁸ Pa s.^[51]

Although the atomic structure of glass shares characteristics of the structure in a supercooled liquid, glass tends to behave as a solid below its glass transition temperature.^[52] A supercooled liquid behaves as a liquid, but it is below the freezing point of the material, and in some cases will crystallize almost instantly if a crystal is added as a core. The change in heat capacity at a glass transition and a melting transition of comparable materials are typically of the same order of magnitude, indicating that the change in active degrees of freedom is comparable as well. Both in a glass and in a crystal it is mostly only the vibrational degrees of freedom that remain active, whereas rotational and translational motion is arrested. This helps to explain why both crystalline and non-crystalline solids exhibit rigidity on most experimental time scales.

Behavior of antique glass

The observation that old windows are sometimes found to be thicker at the bottom than at the top is often offered as supporting evidence for the view that glass flows over a timescale of centuries, the assumption being that the glass was once uniform but has flowed to its new shape, which is a property of liquid.^[54] However, this assumption is incorrect; once solidified, glass stops flowing. The reason for the observation is that in the past, when panes of glass were commonly made by glassblowers, the technique used was to spin molten glass so as to create a round, mostly flat and even plate (the crown glass process, described above). This plate was then cut to fit a window. The pieces were not, however, absolutely flat; the edges of the disk became a different thickness as the glass spun. When installed in a window frame, the glass would be placed with the thicker side down both for the sake of stability and to prevent water accumulating in the lead cames at the bottom of the window.^[55] Occasionally such glass has been found thinner side down or thicker on either side of the window's edge.^[56]

Mass production of glass window panes in the early twentieth century caused a similar effect. In glass factories, molten glass was poured onto a large cooling table and allowed to spread. The resulting glass is thicker at the location of the pour, located at the center of the large sheet. These sheets were cut into smaller window panes with nonuniform thickness, typically with the location of the pour centered in one of the panes (known as "bull's-eyes") for decorative effect. Modern glass intended for windows is produced as float glass and is very uniform in thickness.

Several other points can be considered that contradict the "cathedral glass flow" theory:

• Writing in the American Journal of Physics, materials engineer Edgar D. Zanotto states "... the predicted relaxation time for GeO₂ at room temperature is 10³² years. Hence, the relaxation period (characteristic flow time) of cathedral glasses would be even longer."^[57] (10³² years is many times longer than the estimated age of the Universe.)
• If medieval glass has flowed perceptibly, then ancient Roman and Egyptian objects should have flowed proportionately more—but this is not observed. Similarly, prehistoric obsidian blades should have lost their edge; this is not observed either (although obsidian may have a different viscosity from window glass).^[47]
• If glass flows at a rate that allows changes to be seen with the naked eye after centuries, then the effect should be noticeable in antique telescopes. Any slight deformation in the antique telescopic lenses would lead to a dramatic decrease in optical performance, a phenomenon that is not observed.^[47]
• There are many examples of centuries-old glass shelving that has not bent, even though it is under much higher stress from gravitational loads than vertical window glass.^{[citation needed]}

The above does not apply to materials that have a glass transition temperature close to room temperature, such as certain plastics used in daily life like polystyrene and polypropylene.