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Topic: Crystalline


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In the News (Thu 18 Oct 18)

  
  Crystal - Wikipedia, the free encyclopedia
While the process of cooling usually results in the generation of a crystalline material, under certain conditions the fluid may be frozen in a noncrystalline state.
Crystalline structures occur in all classes of materials, with all types of chemical bonds.
Some crystalline materials may exhibit special electrical properties such as the ferroelectric effect or the piezoelectric effect.
en.wikipedia.org /wiki/Crystal   (606 words)

  
 Runt Research Group, Crystalline Polymers   (Site not responding. Last check: 2007-10-21)
Crystalline polymers are ubiquitous: ranging from the familiar commodity polyolefins to high performance engineering resins like the nylons and poly(ether ether ketone).
Mixtures (blends) containing crystalline polymers are also commonplace, but compared to neat crystalline materials, their crystalline microstructure and crystallization kinetics are less well understood, due in part to the inherent complexity of such mixtures.
The increase in final long period over that of PEO was 2 - 4 nm for the weakly interacting blends by reason of interlamellar diluent placement, as opposed to as large as 10 nm for the strongly interacting mixtures (due to reduction in degree of supercooling).
www.ems.psu.edu /~runt/crystal.htm   (334 words)

  
 What were the conclusions of the IARC 1997 crystalline silica Monograph
Carcinogenicity may be dependent on inherent characteristics of the crystalline silica or on external factors affecting its biological activity or distribution of its polymorphs.
All together, this suggested that crystalline silica does not behave in a consistent way as a carcinogen, and raised doubts on whether crystalline silica per se is a carcinogen.
In spite of its extreme conclusion, the new IARC monograph on crystalline silica is far from having solved the uncertainties surrounding the crystalline silica scientific controversy.
www.ima-eu.org /en/iarc.html   (322 words)

  
 Silicosis in Construction   (Site not responding. Last check: 2007-10-21)
Crystalline silica is the basic component of sand, quartz and granite rock.
Since the 1800s, the silicotic health problems associated with crystalline silica dust exposure have been referred to under a variety of common names, including consumption, ganister disease, grinders' asthma, grinders' dust consumption, grinders' rot, masons' disease, miner's asthma, miner's phthisis, potters' rot, sewer disease, stonemason's disease, chalicosis, and shistosis.
Furthermore, evidence indicates that crystalline silica is a potential occupational carcinogen.
www.osha-slc.gov /SLTC/silicacrystalline/mineoja/demolition.html   (1668 words)

  
 CRYSTALLINE-4   (Site not responding. Last check: 2007-10-21)
Crystalline gold is the rarest and most beautiful form of gold and California Crystalline gold is especially valued by collectors all over the world because of its bright color and unique shapes.
Crystalline gold values are not based on weight but rather the shape and configuration of the piece.
Crystalline gold is very hard to photograph because it is so bright and flashy, the pictures cannot begin to do the specimens true justice.
www.websitetrafficbuilders.com /crystalline-gold-nugget.htm   (229 words)

  
 HA 730-M Crystalline-rock aquifers text   (Site not responding. Last check: 2007-10-21)
Although the crystalline rocks are geologically complex with a structural fabric that generally trends northeast, movement of water through the rocks is totally dependent on the presence of secondary openings; rock type has little or no effect on ground-water flow.
Samples of several types of crystalline rocks were tested in the laboratory and found to range in hydraulic conductivity from 0.000003 to 0.0001 foot per day (table 17).
Water in the crystalline-rock aquifers generally is suitable for most uses because crystalline rocks generally are composed of virtually insoluble minerals, water is in contact with a relatively small surface area in the joints and fractures, and water movement through the joints and fractures generally is rapid and along short flow paths.
capp.water.usgs.gov /gwa/ch_m/M-text6.html   (1056 words)

  
 Concrete Waterproofing - Details   (Site not responding. Last check: 2007-10-21)
Crystalline waterproofing is known for its strength and effectiveness as waterproofing for reservoirs, sewage and water treatment tanks, and tunnels.
Crystalline waterproofing is available as a dry powder, mixed with water to form a slurry, sprayed or brushed onto porous concrete surfaces or applied to newly poured concrete, and worked into the surface.
It should be noted that crystalline waterproofing products can be applied to either side of a wall and still effectively waterproof the wall.
www.toolbase.org /tertiaryT.asp?TrackID=&CategoryID=935&DocumentID=2073   (823 words)

  
 OHS Articles by Joe Kretchik
Crystalline silica is a significant component of the earth's crust.
Workers are usually exposed to crystalline silica in the form of respirable quartz or, less frequently, cristobalite.
Exposure to high levels of respirable crystalline silica causes acute or accelerated forms of silicosis that may occur sooner and are ultimately fatal.
www.mdli.com /ohs/articles/july2003.shtml   (678 words)

  
 Mechanisms of Carcinogenesis by Crystalline Silica in Relation to Oxygen Radicals
The carcinogenic effects of crystalline silica in rat lungs were extensively demonstrated by many experimental long-term studies, showing a marked predominance for adenocarcinomas originating from alveolar type II cells and associated with areas of pulmonary fibrosis (silicosis).
Comparison of surface area and surface charge for different preparations of crystalline silica is important in understanding the relative activities of these preparations in studies on mechanisms of silicosis and silica-induced lung cancer.
We propose that the DNA binding to the crystalline silica surface is important in silica carcinogenesis by anchoring DNA close to sites of oxygen radical production on the silica surface, so that the oxygen radicals are produced within a few Å from their target DNA nucleotides.
ehp.niehs.nih.gov /members/1994/Suppl-10/saffiotti-full.html   (4102 words)

  
 Respiratory Health Effects of Crystalline Silica, National Industrial Sand Association, August 1997, Ricci Bros Sand ...   (Site not responding. Last check: 2007-10-21)
Crystalline silica is in most of the rocks found in the earth's crust and in gravels, sands and soils.
The OSHA PEL for crystalline silica in general industry is listed in the "Code of Federal Regulations," 29 CFR 1910.1000, "Air Contaminants," under Table Z-3, "Mineral Dusts." It is a time-weighted average amount that cannot be legally exceeded for an 8-hour shift during a 40- hour week.
The IARC classification of crystalline silica as "carcinogenic to humans" and the NTP classification of "reasonably anticipated to be a carcinogen," affect specific compliance requirements of the Hazard Communication Standard.
www.riccisand.com /health.html   (2731 words)

  
 CRYSTALLINE - Definition
Imperfectly crystallized; as, granite is only crystalline, while quartz crystal is perfectly crystallized.
{Crystalline lens} (Anat.), the capsular lenslike body in the eye, serving to focus the rays of light.
It consists of rodlike cells derived from the external embryonic epithelium.
www.hyperdictionary.com /dictionary/crystalline   (116 words)

  
 Crystalline Silica: Risks and Policy
Once concerns were raised about crystalline silica, the response (as is common for many chemicals) was to assess the risks quantitatively to find out to what extent this "probable" carcinogen would really cause any cancer, among children in sandboxes, or anyone elsewhere.
As discussed here, the lack of utility of crystalline silica QRA emerges once one considers the very large uncertainties in, and the inadequacy of, the existing crystalline silica database for quantifying risks, and the fact that environmental exposures are ubiquitous.
Taken as a whole, the epidemiologic evidence on crystalline silica exposure per se inducing lung cancer in the absence of lung fibrosis must still be considered scanty and inconsistent, although biologically plausible.
ehp.niehs.nih.gov /members/1995/103p152-155hardy/hardy-full.html   (4072 words)

  
 Crystalline Incandescence   (Site not responding. Last check: 2007-10-21)
Learn how important crystalline incandescence is, and how it will change your life forever.
He was experimenting with certain non crystalline substances, subjecting them to very strong pulsed electro magnetic fields while cooling and applying extreme pressure.
But Mikes theory proposes an opening into an alternative dimension that is bridged by the "crystalline incandescent transducers" as mike now calls the group of compounds he has created.
www.crystalline-incandescence.shopatronics.com /crystalline-incandescence.html   (318 words)

  
 Crystalline Pottery
Crystalline is a special effects glaze found in pottery which contains large (or macro crystals) of zinc orthosilicate.
Crystalline glazes are very runny, that is when the pot reaches peak temperature the glaze is actually slowly flowing off the pot.
But some very spectacular and beautiful crystalline pottery was produced by the art potteries of the late 1800's and early 1900's such as Rookwood Pottery.
home.pinehurst.net /zeke/crystalline.html   (1227 words)

  
 Occupational Hazards - OSHA Offers Information Cards for Crystalline Silica   (Site not responding. Last check: 2007-10-21)
The hazards of exposure to crystalline silica exposure and protection measures from the dust are detailed in new OSHA health hazard information cards available in English and Spanish.
The cards, titled "Crystalline Silica Exposure," were designed to provide a quick reference and recommendations for construction and general industries.
Crystalline silica is a basic component of soil, sand, granite and many other materials.
www.occupationalhazards.com /articles/6736   (311 words)

  
 CRYSTALLINE SILICA, QUARTZ
IARC classified inhaled crystalline silica (quartz or cristobalite) from occupational sources as a Group 1 carcinogen based on sufficient evidence of carcinogenicity in humans and experimental animals; "in making the overall evaluation, the Working Group noted that carcinogenicity in humans was not detected in all industrial circumstances studied.
Crystalline silica may be found in more than one form (polymorphism), depending on the orientation and position of the tetrahedra (i.e., the three-dimensional basic unit of all forms of crystalline silica).
Estimated arithmetic mean respirable crystalline silica levels (form of "crystalline silica" was not specified) for 1950-1959 and 1981-1987 in 20 Chinese mines (10 tungsten, 6 iron-copper, and 4 tin) decreased about 10-fold between those periods.
www.inchem.org /documents/cicads/cicads/cicad24.htm   (12471 words)

  
 Crystalline Development Council   (Site not responding. Last check: 2007-10-21)
Crystalline is open-source, with a licensing model based on the GNU Public License, revision 2.
Senior Members of the CDC are all volunteers, chosen by Crystalline's original author based on their expertise in software development with regard to LCDs in particular.
Crystalline's original author ultimately has final say on all decisions (since he holds the Copyright to the original sourcecode), but this power is only invoked under extreme situations as decisions will usually be made by committee.
www.e-f-w.com /crystalline/cdc.asp   (659 words)

  
 Crystalline Silica
While amorphous silica can be transformed into crystalline forms such as tridymite and cristobalite by heating to high temperatures it is generally only the crystalline forms of silica which are fibrogenic.
In 1997, crystalline silica in the form of quartz or cristobalite was categorized as a human carcinogen by the International Agency for Research on Cancer (IARC) [8].
Crystalline silica has been linked with cases of autoimmune diseases such as scleroderma, systemic lupus erythematosus (lupus), rheumatoid arthritis etc. Chronic renal disease, possibly due to immunological abnormalities, has also been linked with silica dust exposure.
www.asosh.org /Programmes/SORDSA/Crystalline_silica.htm   (3816 words)

  
 ice   (Site not responding. Last check: 2007-10-21)
However, the reverse does not apply: crystalline (high temperature) ice does not convert to amorphous when its temperature is lowered.
The reason for this asymmetry is that crystalline ice is already in a minimum energy configuration, so dropping the temperature (think: random, thermal motions) of the molecules can do nothing to change their geometrical arrangement.
This occurs because the radiation breaks the bonds which hold the molecules in their repeating patterns in crystalline ice.
www.ifa.hawaii.edu /~jewitt/ice.html   (481 words)

  
 Introduction to Cubic Crystal Lattice Structures   (Site not responding. Last check: 2007-10-21)
The outstanding macroscopic properties of crystalline solids are rigidity, incompressibility and characteristic shape.
All crystalline solids are composed of orderly arrangements of atoms, ions, or molecules.
The macroscopic result of the microscopic arrangements of the atoms, ions or molecules is exhibited in the symmetrical shapes of the crystalline solids.
www.okstate.edu /jgelder/solstate.html   (538 words)

  
 ESA Science & Technology: The crystalline revolution: ISO's finding opens a new research field, 'astro-mineralogy'
The reason why crystalline silicates had not been detected before in stars has to do with their low temperatures.
However, crystalline silicates are a large family and their chemical signatures can be very similar; to enlarge the list of precise crystals more work will be needed, say experts in space chemistry.
There's at least another one: crystalline silicates are found around old stars, in protoplanetary disks and in our own Solar System, but not in the space among the stars; astronomers can't explain it yet.
sci.esa.int /science-e/www/object/index.cfm?fobjectid=12856   (804 words)

  
 Toxic Injuries: Silica: Definition of Crystalline Silica   (Site not responding. Last check: 2007-10-21)
The polymorphic forms of crystalline silica are alpha quartz, beta quartz, tridymite, cristobalite, keatite, coesite, stishovite, and moganite [Ampian and Virta 1992; Heaney 1994; Guthrie and Heaney 1995].
They concluded that there is "sufficient evidence in humans for the carcinogenicity of inhaled crystalline silica in the form of quartz or cristobalite from occupational sources" (i.e., IARC category "Group 1" carcinogen).
A later NIOSH report (Review of the Literature on Crystalline Silica) concluded that additional toxicologic and epidemiologic studies were needed to determine the relationship between respirable crystalline silica dose and the risk of developing silicosis and lung cancer and the adverse effects of crystalline silica on the kidney.
www.opolaw.com /toxic-injury/silica/articles/niosh-article1.html   (1116 words)

  
 02/11/1991 - Label requirements for crystalline silica
If the warning threshold for crystalline silica is 0.1 percent respirable, can you define or cite for us an "approved" method or methods for the measurement of the respirable portion that is applicable to bulk samples.
These samples collect the respirable fraction of the total dust to which an employee is exposed in the workplace air during the employee's normal course of duties, and as such, represent a measurable quantification of the airborne concentration of respirable silica.
If the warning threshold for crystalline silica is 0.1% respirable, can you define or cite for us an "approved" method or methods for the measurement of the respirable portion that is applicable to bulk samples.
www.osha.gov /pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=20191   (1174 words)

  
 Crystalline Silica Primer   (Site not responding. Last check: 2007-10-21)
Crystalline silica is the scientific name for a group of minerals composed of silicon and oxygen.
The term crystalline refers to the fact that the oxygen and silicon atoms are arranged in a three-dimensional repeating pattern.
Because crystalline silica is an extremely common mineral and the HCS will affect many mineral commodities, it is important then, that there be as clear an understanding as possible of what is and what is not crystalline silica, and where it is found and used, and how it is qualitatively and quantitatively identified.
geology.usgs.gov /pdf/silica.html   (481 words)

  
 Paper, Film, & Foil Converter: Hot melt adhesives comprising crystalline and amorphous polymers   (Site not responding. Last check: 2007-10-21)
Formulations containing both amorphous and crystalline polymers are uncommon because of the incompatibility and phase separations of these polymers.
The use of a small amount of amorphous water sensitive polymer with crystalline water sensitive polymers improves the performance properties of hot melt adhesives compared with an adhesive made from individual crystalline or amorphous polymers.
The use of crystalline polymers in hot melt formulations based on amorphous water sensitive polymers also gave increased humidity resistance and non-blocking characteristics that were not possible using other crystalline additives such as wax and polymers.
www.findarticles.com /p/articles/mi_m3541/is_12_75/ai_81113520   (1147 words)

  
 Crystalline Images - Custom Shower doors   (Site not responding. Last check: 2007-10-21)
Crystalline Images has a patented process for producing carved glass designs on flat glass.
Crystalline Images is the west coast's largest producer of sand blasted glass for use in commercial and residential applications.
Crystalline Images has been producing custom tables for a select group of interior designers for years.
www.crystallineimages.com   (389 words)

  
 Crystalline and Amorphous Solids   (Site not responding. Last check: 2007-10-21)
Crystalline solids are arranged in fixed geometric patterns or lattices.
Crystalline solids also show a definite melting point and so they pass rather sharply from solid to liquid state.
When the drug is crystallizing, if it forms a crystalline solid, there is space in the crystal for the ice to come out leaving the drug and the components.
www.utmem.edu /physpharm/.003a.html   (356 words)

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