Тишакова Татьяна Станиславовна канд хим н., ассистент; Левашова Ольга Леонидовна канд фарм н., ассистент; Савельева Елена Валерьевна ассистент. В сборнике представлены тезисы


CALCITE Davia Nelson, group 10. Scientific adviser is Tatyana Tishakova



бет67/79
Дата12.07.2016
өлшемі1.64 Mb.
#193027
түріТезисы
1   ...   63   64   65   66   67   68   69   70   ...   79

CALCITE

Davia Nelson, group 10. Scientific adviser is Tatyana Tishakova


Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common and widespread mineral with highly variable forms and colours. Calcite is best recognized by its relatively low Mohs hardness (3) and its high reactivity with even weak acids, such as vinegar, plus its prominent cleavage in most varieties.

Microbiologically precipitated calcite has a wide range of applications, such as soil remediation, soil stabilization and concrete repair.

The primary use for calcite is in the construction industry. The products containing calcite are commonly used on building projects. These are commonly used to create cement or concrete.

Calcite is also used in commercial acid neutralization. It has been spread on fields to reduce acid, used in rivers that have been turned acidic by mining or other reason.

These acid neutralization properties have also led to it being used in antacid tablets. Calcium carbonate is mixed with sugar and flavoring to make chewable tablets to neutralize stomach acids.

Calcium carbonate is also used to absorb harmful gasses during the use of fossil fuels.

These can also be ground up and added to animal feed for animals that require a calcium rich diet.

In powdered form it is often used as a whitening agent. This is commonly used in paint.

It is also used in many cleaning agents because it is hard enough to remove stains and dirt, but not hard enough to damage the cleaning surface.

Ground limestone is also used in coal mines to reduce the coal dust in the air. It is sprayed onto the walls and roof of the mine. It also has the added benefit of reflecting light in the dark environment.

High grade calcite was also used in World War II for gun sights, specifically in bomb sights and anti-aircraft weaponry.

Calcite in the form of marble has been one of the preferred stones for large ornaments, statues and memorials since ancient times. The Parthenon Marbles, also called the Elgin Marbles, are a series of classical Greek sculptures originally decorating the Acropolis in Athens. A common modern ornamental use of calcite is for cemetery memorial stones.

For healing physical ailments, calcite is used for kidney problems, infections and for the decalcification of joints. The mineral is used for relieving backaches and to increase physical strength, improving the health of teeth and eyes. This healing crystal is considered a good general-purpose healer. Smooth "eggs" or wands of calcite are used in conjunction with massage to spread its healing and cleansing energy throughout the body by removing negative energy. Holding calcite, or placing it at various chakra points, energizes the body's natural electrical system. Others use calcite for energy by placing their feet on a large piece of calcite. This healing crystal is an also good for use in elixirs.

A new form of biomineralization has been found in the pineal gland of the human brain. The crystals are 10 to 20 μm in length and have well-defined morphologies. The crystals contain only the elements calcium, carbon and oxygen. Selected-area electron diffraction (SAED) and near infrared Raman spectroscopy established that the crystals are calcite. This is the first report of the presence of non-pathological calcite in the human body. These microcrystals are believed to be responsible for the previously observed second harmonic generation (SHG) in pineal tissue samples and they may also exhibit piezoelectricity, suggesting a unique electromechanical biological transducer mechanism in the human brain.


SNOWFLAKE OBSIDIAN

Ahmad Salameh, group 10. Scientific adviser is Tatyana Tishakova


Obsidian is a naturally occurring volcanic glass. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth.

Obsidian is commonly found within the margins of rhyolitic lava flows known as obsidian flows, where the chemical composition (high silica content) induces a high viscosity and polymerization degree of the lava.

The inhibition of atomic diffusion through this highly viscous and polymerized lava explains the lack of crystal growth.

Obsidian is hard and brittle; it therefore fractures with very sharp edges, which were used in the past in cutting and piercing tools, and has been used experimentally as surgical scalpel blades.

Obsidian can be found in :

– Argentina, Armenia, Azerbaijan, Canada, Chile, Georgia, Greece, El Salvador, Guatemala, Iceland, Italy, Japan, Kenya, Mexico, New Zealand, Peru, Scotland, Turkey and the United States.

– east of the Sierra Nevada in California. Yellowstone National Park has a mountainside containing obsidian located between Mammoth Hot Springs and the Norris Geyser Basin

– U.S. states including Arizona, Colorado, New Mexico, Texas, Utah, Washington Oregon and Idaho.

– in the eastern U.S. states of Virginia, as well as Pennsylvania and North Carolina.

Though not approved by the US Food and Drug Administration (FDA) for use on humans, obsidian is used by some surgeons for scalpel blades, as well-crafted obsidian blades have a cutting edge many times sharper than high-quality steel surgical scalpels, the cutting edge of the blade being only about 3 nanometers thick. For surgery and other purposes and has written articles on the subject. Obsidian scalpels may currently be purchased for surgical use on research animals.

Obsidian is also used for ornamental purposes and as a gemstone.

RUTILE IN QUARTZ

Araoye Jesupelumi Israel, group 10. Scientific adviser is Tatyana Tishakova


Rutile is a mineral composed primarily of titanium dioxide – TiO2.Natural rutile may contain up to 10% iron and significant amounts of niobium and tantalum. Rutile derives its name from the Latin word rutilus, red, in reference to the deep red color observed in some specimens when viewed by transmitted light.Rutile is the most common natural form of TiO2. RUTILATED QUARTZ, is a type of quartz with needle-like rutile embedded in it. The rutile needles can be reddish, which is what rutile means in Latin, or they may be golden, silvery, or on very rare occasions, greenish.Rutile has among the highest refractive indices at visible wavelengths of any known crystal, and also exhibits a particularly large birefringence and highdispersion. Owing to these properties, it is useful for the manufacture of certain optical elements, especially polarization optics, for longer visible and infrared wavelengths up to about 4.5μm. Birefringence is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light. Nanoscale particles of rutile are highly effective in the absorption of ultraviolet radiation. Hence they are used in sunscreens to protect against U.V induced skin damage 3.Rutilated Quartz is said to be beneficial for food disorders, strengthen the immune system, aid regeneration of tissue, reduce fatigue and depression, improve respiratory illness, stability of all physical systems and general health, and facilitate absorption of nutrients from food.



Достарыңызбен бөлісу:
1   ...   63   64   65   66   67   68   69   70   ...   79




©dereksiz.org 2024
әкімшілігінің қараңыз

    Басты бет