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Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (November 2009) external cdrom
Endodontic files and reamers are surgical instruments used by dentists when performing root canal treatment. These tools are particularly used to clean and shaped the root canal, with the concept being to perform complete chemomechanical debridement of the root canal to the length of the apical foramen. dvd duplicator burner
Files are commonly made from metal; usually stainless steel or nickel-titanium alloy. Files may be made from metal blanks that are twisted or machined to produce various sizes and tapers. Typical file lengths are 21mm, 25mm, 31mm. An ISO sizing system is used to describe the tip size of endodontic files. Files are usually colour coded in an ISO colour system to aid the dentist. Typically steel files have 2% tapers, but in recent years Ni-Ti files with up to 12% tapers have been popularized. dvd burner duplicator
Fracture of an endodontic file may cause the endodontic treatment to have a lower success rate. Fragments of files may be removed using a retrieval system, but this is very technically demanding, and many fragments are left in-situ without problems.
Due to the risk of prion disease transmission files should not be re-used.
Categories: Dentistry | EndodonticsHidden categories: Articles lacking sources from November 2009 | All articles lacking sources
Sunday, May 9, 2010
Endodontic files and reamers
Trestle table
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Construction and uses
Trestle tables figure prominently in the traditional Americana style of household furnishings, usually accompanied by spindle-backed chairs. The trestles in this case are normally of much higher quality, often made of oak and braced with a stretcher beam using a keyed tenon through the centre of each trestle. These typically support a high-quality waxed oak tabletop.
Trivia audio component rack
The decorator's trestle table is acknowledged as the basis of the pseudonym adopted by Robert Tressell, a decorator-turned-author, for his novel The Ragged Trousered Philanthropists, published in 1910. oak tv console
See also plasma tv wall cabinet
Refectory table
Table (furniture)
Trestle desk
References
^ Webster's Third New International Dictionary
^ Britannica.com/Table
^ "The Dictionary of Art", Jane Turner, Grove 1996 p.217
^ Gordon Campbell, The Grove Encyclopedia of Decorative Arts Vol 2, Oxford University Press US (2006) p411
^ http://www.shaker.net/html/trestle.html Examples of modern trestle table and chairs
^ http://www.oldandsold.com/articles03/hf1.shtml Americana-style trestle table
External links
Merriam-Webster Online Dictionary
National Gallery of Art, Washington, DC
Historical reference at Bartleby/Columbia Encyclopedia
Photos of a trestle table broken down into individual components at RL Goins
Categories: Tables (furniture)Hidden categories: Articles needing cleanup from July 2009 | All pages needing cleanup
Dimethyl sulfate
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History
Dimethyl sulfate was first discovered in the early 1800s in an impure form. P. Claesson later extensively studied its preparation.
Production 16 oz propane
Dimethyl sulfate can be synthesized in the laboratory by many different syntheses, the simplest being the esterification of sulfuric acid with methanol: zinc stearate
2 CH3OH + H2SO4 (CH3)2SO4 + 2 H2O propane refill
Another possible synthesis involves distillation of methyl hydrogen sulfate:
2 CH3HSO4 H2SO4 + (CH3)2SO4
Methyl nitrite and methyl chlorosulfonate also result in dimethyl sulfate:
CH3ONO + (CH3)OSO2Cl (CH3)2SO4 + NOCl
In the United States, Me2SO4 has been produced commercially since the 1920s. A common process is the continuous reaction of dimethyl ether with sulfur trioxide.
(CH3)2O + SO3 (CH3)2SO4
Uses
Dimethyl sulfate is best known as a reagent for the methylation of phenols, amines, and thiols. Typically, one methyl group is transferred more quickly than the second. Methyl transfer is typically assumed to occur via an SN2 reaction. Although dimethyl sulfate is highly effective and affordable, its toxicity has encouraged the use of other methylating reagents. Methyl iodide is a reagent used for O-methylation, like dimethyl sulfate, but is less hazardous and more expensive. Dimethyl carbonate has far lower toxicity compared to both dimethyl sulfate and methyl iodide and can be used to instead of dimethyl sulfate for N-methylation. In general the toxicity of methylating agents is correlated with their efficiency as methyl transfer reagents.[citation needed]
Methylation at oxygen
Most commonly, Me2SO4 is employed to methylate phenols. Some simple alcohols are also suitably methylated, as illustrated by the conversion of tert-butanol to t-butyl methyl ether:
2 (CH3)3COH + (CH3O)2SO2 2 (CH3)3COCH3 + H2SO4
Alkoxide salts are rapidly methylated:
RO - Na + + (CH3O)2SO2 ROCH3 + Na(CH3)SO4
The methylation of sugars is called Haworth methylation
Methylation at amine nitrogen
Me2SO4 is used to prepare both quaternary ammonium salts or tertiary amines:
C6H5CH=NC4H9 + (CH3O)2SO2 C6H5CH=N+(CH3)C4H9 + CH3OSO3-
Quaternized fatty ammonium compounds are used as a surfactant or fabric softeners. The methylation of a tertiary amine is illustrated as:
CH3(C6H4)NH2 + (CH3O)2SO2 (in NaHCO3 aq.) CH3(C6H4)N(CH3)2 + Na(CH3)SO4
Methylation at sulfur
Similar to the methylation of alcohols, mercaptide salts are easily methylated by Me2SO4:
RS-Na+ + (CH3O)2SO2 RSCH3 + Na(CH3)SO4
An example is:
p-CH3C6H4SO2Na + (CH3O)2SO2 p-CH3C6H4SO2CH3 + Na(CH3)SO4
This method has been used to prepare thioesters:
RC(O)SH + (CH3O)2SO2 RC(O)S(CH3) + HOSO3CH3
Other uses
Dimethyl sulfate can effect the base-specific cleavage of guanine in DNA by rupturing the imidazole rings present in guanine. This process can be used to determine base sequencing, cleavage on the DNA chain, and other applications.
Dimethyl sulfate also methylates adenine in single-stranded portions of DNA (e.g., those with proteins like RNA polymerase progressively melting and re-annealing the DNA). Upon re-annealing, these methyl groups interfere with adenine-guanine base-pairing. Nuclease S1 can then be used to cut the DNA in single-stranded regions (anywhere with a methylated adenine). This is an important technique for analyzing protein-DNA interactions.
Safety
Dimethyl sulfate is likely carcinogenic and mutagenic, poisonous, corrosive, environmentally hazardous and volatile (presenting an inhalation hazard). Some consider it a potential chemical weapon. Dimethyl sulfate is absorbed through the skin, mucous membranes, and gastrointestinal tract. There is no strong odor or immediate irritation to warn of lethal concentration in air. Delayed toxicity allows potentially fatal exposures to occur prior to development of any warning symptoms. Symptoms may be delayed 6-24 hours. Concentrated solutions of bases (ammonia, alkalis) can be used to hydrolyze minor spills and residues on contaminated equipment, but the reaction may become violent with larger amounts of dimethyl sulfate (see ICSC). Although the compound hydrolyses in water, plain water cannot be assumed to hydrolyze dimethyl sulfate quickly enough for decontamination purposes. The hydrolysis products, monomethyl sulfate and methanol, are environmentally hazardous. In water, the compound is ultimately hydrolyzed to sulfuric acid and methanol.
References
^ a b c Suter, C. M. The Organic Chemistry of Sulfur Tetracovalent Sulfur Compounds John Wiley & Sons, Inc. 1944. p 49-53
^ Shirley, D. A. Organic Chemistry. Holt, Rinehart and Winston. 1966. p. 253
^ a b "Substance Profiles - Dimethyl Sulfate". 11th Report on Carcinogens. Department of Health and Human Services. http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s078dime.pdf.
^ a b Fieser, L. F. and Fieser, M. Reagents for Organic Synthesis. John Wiley & Sons, Inc. 1967. p. 295
^ W. C. Shieh, S. Dell and O. Repic (2001). "1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) and Microwave-Accelerated Green Chemistry in Methylation of Phenols, Indoles, and Benzimidazoles with Dimethyl Carbonate". Organic Letters 3 (26): 42794281. doi:10.1021/ol016949n.
^ a b c Dupont product information
^ W. N. Haworth, J. Chem. Soc. 107, 13 (1915).
^ Streitwieser, A., Heathcock, C. H., and Kosower, E. M. Introduction to Organic Chemistry. Prentice-Hall Inc. 1992. p. 1169
^ Rippey, J. and Stallwood, M. Emergency Medicine Journal 2005;22:878-879
External links
WebBook page for C2H6SO4
International Chemical Safety Card 0148
IARC Monograph: "Dimethyl sulfate"
Categories: Organosulfates | Methylating agents | IARC Group 2A carcinogensHidden categories: All articles with unsourced statements | Articles with unsourced statements from August 2008
Cirrus Logic
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Brief History
Patil Systems, Inc., is founded in Salt Lake City in 1981, by Dr. Suhas Patil and renamed as Cirrus Logic when it moved to Silicon Valley in 1984 to focus on solutions for the growing PC components market. Michael Hackworth was named president and chief executive officer in January 1985, and served as CEO until February 1999. It joined the Nasdaq market listing in 1989 (symbol: CRUS). Cirrus Logic acquired Crystal Semiconductor, a leading supplier of analog and mixed-signal converter ICs, in 1991. In the early 1990s, Cirrus Logic became a leading supplier of PC graphics chips, audio converters and chips for magnetic storage products. David D. French joined Cirrus Logic, Inc., as president and chief operating officer in June 1998 and was named chief executive officer in February 1999. Soon after joining the company, through an acquisition strategy Mr. French repositioned the company into a premier supplier of high-performance analog and digital processing chip solutions for consumer entertainment electronics. In June 2005, Cirrus Logic sold its video products operation to an investment firm, creating privately-owned Magnum Semiconductor. After resigning in March 2007, Jason Rhode, formerly the vice president and general manager of Cirrus' Mixed Signal Audio Division, was named president and CEO in May 2007. Today, Cirrus Logic is focused on its high-precision technologies for digital signal processing components for audio and energy markets.
Timeline of key events patch panel cat 5e
1981 Patil Systems Inc. is founded in Salt Lake City by Dr. Suhas Patil. Company focuses on IC solutions for the growing PC components market. cat5 patch panel
1984 Patil Systems Inc. renamed Cirrus Logic and moves headquarters to Silicon Valley 5e patch panel
1989 Company goes public and is listed on the Nasdaq exchange under the ticker symbol CRUS.
1991 Cirrus Logic acquires Crystal Semiconductor, a leading supplier of analog and mixed-signal converter ICs.
1996 Cirrus Logic exits from the PC graphics card business
1998 David D. French joins company as president and chief operating officer in June and becomes chief executive officer in February 1999. In the fall, company spins out its communication business unit.
2001 Cirrus Logic announces plan to begin exit from magnetic storage chip business.
2001 Cirrus Logic acquires several start-up companies with technologies in video decoding, video encoding, wireless networking, and networked digital audio.
2003 Cirrus Logic closes wireless networking operations.
2005 Cirrus Logic sells video product assets to investment firm, creating Magnum Semiconductor (company maintains minority equity position).
2007 Jason Rhode, formerly vice president and general manager of Cirrus' Mixed-Signal Audio division, is named president and chief executive officer, replacing French who resigned in March. In July, Cirrus Logic acquires Apex Microtechnology, a leading provider of high-power products for industrial and aerospace markets.
Graphics history
CL-GD5429 VLB
In the early 1990s, Cirrus Logic was a leading supplier of low-cost PC graphics chips. Cirrus's Microsoft Windows 2D GUI accelerators (GDI) were among the fastest in the low-end market-segment, outperforming competing VGA-chips from Oak Technologies, Trident Microsystems, and Paradise (Western Digital). For example, the Cirrus GD5422 (1992) supported hardware acceleration for both 8-bit color and 16-bit color. It was one of the lowest-priced SVGA controllers to support both.
By the mid-1990s, when PC's had migrated to the PCI bus, Cirrus had fallen behind S3 and Trident Microsystems. When the announced release date of the GD5470 "Mondello" came and went, Cirrus's reputation in desktop PC-graphics suffered. (Mondello would have been the company's first 3D-accelerator, but instead became vaporware.)
The company's final graphics chips, the GD546x "Laguna" series of PCI/AGP 3D-accelerators, were novel in that they were one of the few video cards to use Rambus RDRAM. However, like many other 2D/3D chips at the time, the feature set of perspective-correct texture mapping, bilinear filtering, single-pass lighting, gouraud shading, and alpha blending, was both slow and incomplete.
Graphics chipsets
CL-GD5464 "Laguna 3D"
DESKTOP
CL-GD410 + 420 - ISA SVGA chipset, Video 7 VEGA VGA (1987)
CL-GD510 + 520 - ISA SVGA "Eagle II" chipset, known for 100% CGA emulation. (1988)
CL-GD5320 - ISA SVGA chipset. (1990)
CL-GD5401 - ISA SVGA chipset, also known as Acumos VGA (AVGA1)
CL-GD5402 - ISA SVGA chipset, also known as Acumos VGA (AVGA2)
CL-GD5410 - ISA SVGA chipset, Low-to-mid-end DRAM-based cards (accelerated), some laptop chipsets. Known for integrating graphic card components into one chip (built-in RAMDAC and clock generators) at an early point. (1991)
CL-GD5420 - ISA SVGA chipset, highly integrated (15 bit RAMDAC + PLL), 1 MB.
CL-GD5421 - ISA SVGA chipset, highly integrated (15/16 bit RAMDAC + PLL), 1 MB.
CL-GD5422 - Enhanced version of the 5420 (32-bit internal memory interface, 15/16/24 bit RAMDAC. An ISA video card carrying this chipset offered 1280x1024 interlaced max resolution).
CL-GD5424 - VLB version of the 5422, but resembles the 5426 in some respects.
CL-GD5425 - True color VGA controller w/ TV out.
CL-GD5426 - Hardware BitBLT engine. ISA bus and VLB up to 2 MB of memory.
CL-GD5428 - Enhanced version of the 5426. Faster BITBLT engine.
CL-GD5429 - Enhanced version of the 5428; supports higher memory clock and has memory-mapped I/O.
CL-GD5430 - Similar to 5429, but with 543x core (32-bit host interface).
CL-GD5434 - Alpine family chip with 64-bit internal memory interface. Only supports 64-bit mode if equipped with 2 MB of video memory; commonly equipped with 1 MB, extendable to 2 MB.
CL-GD5436 - An optimized 5434.
CL-GD5440 - 5430 with motion-video acceleration. (CL-GD54M40 has integrated filters.)
CL-GD5446 - 64-bit Alpine VisualMedia accelerator. 2D-only; adds motion-video acceleration to the CL-GD5436.
CL-GD546X - The Laguna VisualMedia family of 2D, 3D, and video accelerators. '64 and '65 include 3D acceleration. (PCI, AGP). These chips use a single channel of RDRAM memory, providing up to 600 MB/s bandwidth. The '62 lacks 3D acceleration. All include a BitBLT engine, video windows, and 64x64 hardware cursor.
CL-GD5480 - 64-bit Alpine accelerator with 100 MHz SGRAM
MOBILE
CL-GD610 + 620 - (1989)
CL-GD6420/6440 Used in some laptops, similar to older Cirrus chipsets (5410/AVGA2).
CL-GD6205/6215/6225/6235 - Compatible with the 5420.
CL-GD7541/7542/7543/7548 - Compatible with the 5428/3x.
See also
Graphics card
Graphics processing unit
References
^ "Company Profile for Cirrus Logic Inc (CRUS)". http://www.zenobank.com/index.php?symbol=CRUS&page=quotesearch. Retrieved 2008-10-23.
External links
Cirrus Web Site
Categories: Companies listed on NASDAQ | Fabless semiconductor companies | Graphics hardware companies | Companies established in 1981 | Companies based in Austin, TexasHidden categories: Articles needing cleanup from October 2007 | All pages needing cleanup
The Trouble with Trillions
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Plot
On January 1, right after New Year's Eve, Ned completes his yearly taxes. Later that year, just before midnight on April 15, Homer realizes he did not file his tax return. He rushes and provides false information before driving to the post office. When the tax returns are sent to the IRS, Homer's oddly-packaged return fatefully bounces into the "Severe Audit" bin. The IRS discovers Homer's fraud and arrests him. Held by the government, Homer says he will do anything to stay out of prison. Agent Johnson of the FBI decides that Homer can be useful. With a hidden microphone under his shirt, Homer uncovers that his co-worker Charlie leads a group planning to assault all government officials.
With his superiors impressed, Johnson sends Homer on a secret mission. They reveal that in 1945, President Harry Truman printed a one trillion-dollar bill (with his photo on it) to help reconstruct post-war Europe. He handed the bill over to Montgomery Burns to transport to the Europeans. However, the money never arrived and the FBI suspects Burns still has the money with him. As satellite photography can only confirm that the trillion-dollar bill is not on the roof of Burn's home, Homer is sent in to investigate. Arriving at Burns's estate, Homer searches for the money before Burns, who believes Homer is a reporter from Collier's magazine, reveals that he kept the money on his person. Johnson and Agent Miller burst in and arrests Burns for grand-grand-grand-grand-larceny. Burns shouts how the US government oppresses the average American and tells Homer to write, "Don't let the government push you around!" in his article. Moved by Burns's speech, Homer knocks out the FBI agents and frees Burns. bed sheet satin
The three men meet with Fidel Castro. daybed bedding set
The two men hurry to obtain Smithers for help, who suggests they leave the country. Burns takes Smithers and Homer in his old plane, setting off to find an island and start a new country. Over the Caribbean, Burns finds a fine island, although it already has a name and is in fact the country, Cuba. Going before Fidel Castro (after learning, much to the surprise of both Burns and Simpson, that Batista is no longer leader of Cuba), Burns fails to buy the island when Fidel asks to see the trillion dollar bill, and is handed the bill. When Burns asks for it back, Castro responds: "Give what back?". Then, the episode immediately cuts to a scene where Burns, Smithers, and Homer are on a make-shift raft. Burns announces he will merely bribe the jury when Smithers, Homer, and himself are put on trial, prompting Homer to exclaim "God bless America!" and salute. flannel sheets king
Production
The episode was written by Ian Maxtone-Graham, though the original draft of the plot was much different. Originally, Homer was to learn that he was a Native American, and would try to exploit it to not have to pay taxes. The idea had been going well for a few days, but the staff did not actually know whether Native Americans had to pay taxes. When the writers found out that they did, the whole plot had to be discarded. Executive producer Mike Scully's brother Brian pitched the idea of the trillion dollar bill, which they accepted, as they were out of ideas.
Cultural references
The title of this episode refers to the Star Trek episode "The Trouble with Tribbles". The scene where it is April 15 when the post office is crowded, Kent Brockman asks Otto why he left his tax return to the last minute and replies "Tax returns? Isn't this the line for Metallica?" The scene where the FBI agent sits near Homer is a reference to the film JFK. While Homer, Mr. Burns, and Smithers are in Cuba, a billboard can be seen with a picture of Che Guevara being used to advertise Duff Beer. Burns seems to own the suit Charlie Chaplin was buried in, probably a reference to Chaplin's corpse being stolen after his death. Agent Johnson of the FBI is probably a reference to the two Agent Johnsons in Die Hard.
Reception
The authors of the book I Can't Believe It's a Bigger and Better Updated Unofficial Simpsons Guide, Warren Martyn and Adrian Wood, did not enjoy the episode, calling it, "Rather dull and unfunny," and, "A mediocre episode at best that makes Burns out to be altruistic (which he's not) and very stupid in letting Castro have his money (which he so wouldn't)." The Daily Telegraph characterized the episode as one of "The 10 Best Simpsons TV Episodes." The article noted the episode contained "one of the few gags in comedy history about relying too heavily on surveillance photography in spying."
Ian Jones and Steve Williams criticized all of season 9 for lacking an episode that centered around Burns, as they consider Burns to be the crux of many good episodes, though they noted that "The Trouble with Trillions" came the closest, with Burns having a supporting role. In a review of the ninth season of The Simpsons, Isaac Mitchell-Frey of the Herald Sun described the episode as "brilliant", and highlighted it along with episodes "Bart Carny" and "The Joy of Sect".
The episode was screened on BBC Two in January 1999, before any other episode from season six or later were seen by terrestrial viewers in the UK, as part of a night of Cuba-themed programmes.
References
^ a b c d Martyn, Warren; Wood, Adrian (2000). "The Trouble with Trillions". BBC. http://www.bbc.co.uk/cult/simpsons/episodeguide/season9/page20.shtml. Retrieved 2007-11-03.
^ a b c Gimple, Scott (1999). The Simpsons Forever!: A Complete Guide to Our Favorite Family ...Continued. Harper Collins Publishers. p. 36. ISBN 0-06-098763-4.
^ "The Trouble with Trillions" The Simpsons.com. Retrieved on November 3, 2007
^ Scully, Mike. (2006). The Simpsons season 9 DVD commentary for the episode "The Trouble with Trillions". [DVD]. 20th Century Fox.
^ Maxtone-Graham, Ian. (2006). The Simpsons season 9 DVD commentary for the episode "The Trouble with Trillions". [DVD]. 20th Century Fox.
^ a b Walton, James (July 21, 2007). "The 10 Best Simpsons TV Episodes (In Chronological Order)". The Daily Telegraph: pp. Page 3.
^ Ian Jones, Steve Williams. ""NOW LET US NEVER SPEAK OF IT AGAIN"". Off The Telly. http://www.offthetelly.co.uk/comedy/simpsons/decade.htm. Retrieved 2007-11-04.
^ Mitchell-Frey, Isaac (February 11, 2007). "Comedy - The Simpsons, Series 9". Herald Sun: p. E12.
External links
Wikiquote has a collection of quotations related to: "The Trouble with Trillions"
The Simpsons portal
"The Trouble with Trillions" at The Simpsons.com
"The Trouble with Trillions" episode capsule at The Simpsons Archive
"The Trouble with Trillions" at TV.com
"The Trouble with Trillions" at the Internet Movie Database
Categories: The Simpsons episodes, season 9 | 1998 television episodes
Cycling power meter
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Usage
Training using a power meter is increasingly popular. Most power meters also measure and display heart rate as well as riding speed, distance and time. Power meters provide an objective measurement of real output that allows training progress to be tracked very simplyomething that is more difficult when using, for example, a heart rate monitor alone. Cyclists will often train at different intensities depending on the adaptations they are seeking. A common practice is to use different intensity zones. When training with power, these zones are usually calculated from the power output corresponding to the so called lactate threshold or MAP (maximal aerobic power).
Power meters provide instant feedback to the rider about their performance and measure their actual output; heart rate monitors measure the physiological effect of effort and therefore ramp up more slowly. Thus, an athlete performing "interval" training while using a power meter can instantly see that they are producing 300 watts, for example, instead of waiting for their heart rate to climb to a certain point. In addition, power meters measure the force that moves the bike forward multiplied by the velocity, which is the desired goal. This has two significant advantages over heart rate monitors: 1) An athlete's heart rate may remain constant over the training period, yet their power output is declining, which they cannot detect with a heart rate monitor; 2) While an athlete who is not rested or not feeling entirely well may train at their normal heart rate, they are unlikely to be producing their normal power heart rate monitor will not reveal this, but a power meter will. Finally, power meters enable rider to experiment with cadence and evaluate its effect relative to speed and heart rate. bath bubble spa
Interfaces electric massager
Most cycling power meters use a set of wires to transmit power information to a computer mounted on the bicycle; this system has a serious disadvantage of having fine electrical cables being run all over the bicycle, making it harder to clean as well as using a fair number of fasteners to hold them up. However as of late 2008/early 2009, there is a general trend to move towards wireless systems . A popular wireless system is ANT+ by ANT. Currently, Garmin, Quarq, SRM (Schoberer_Rad_Metechnik) and PowerTap have deployed this interface for various purposes on the bicycle. electric massagers
Power meter types
Crankset
Crankset power meters measure the torque applied to both pedals via strain gauges positioned within the crank spider. A calculation of power is derived from the deflection of the strain gauges and pedaling cadence.
These units require specific cranksets, but can be relatively simple to interchange between bikes depending on compatibility.
Bottom bracket
Bottom bracket power meters rely on the torsional deflection in the BB shaft, this is done by the shaft having a disc at each end with perforations, these perforations are detected using non-contact photo-electric sensors that detect when torque is applied to the left pedal and then doubled. Data is sent digitally to a handlebar mounted computer unit.
These units are difficult to interchange and require a different bottom bracket unit for each bike. The only company producing such systems, Ergomo, went into liquidation in 2008.
bottom bracket with connection cables
Freehub
A freehub power meter uses the same strain gauges that are present in the crank power meters but are located in the rear wheel hub and measure the power after the drive chain, because of this, power should theoretically be measured less than the crank based power meters. Because these units are built into the rear wheel it is simple to interchange between bikes as long as the wheels are compatible.
Chain
At the heart of chain units is essentially a guitar pick-up that mounts to the cycle's chain stay. With this system the pick up detects the chain vibration and speed and mathematically converts it to a power output.
Opposing force
This method of power measurement relies on Newton's Third Law: applied and opposing forces must be equal. Crankset, bottom bracket, freehub, and chain systems measure applied forces and, therefore, require placement of sensors near the bike pedal. Opposing force power meters measure hill slope (gravity), wind speed, bike acceleration (inertia), and frictional drag. Opposing force power meters place all key sensors in the computer head, resulting in lighter weight, extreme bike-to-bike portability, and lower cost.
Applied force
This method monitors the forces applied to the pedal by the cyclist's foot. Sensors in the shoe or pedal measure the forces as the cranks rotate, and calculate the power based on the magnitude and direction of the applied force, and the angular velocity of the crank. Advantages of this technique include independent measurement of power for each leg, measurement of efficiency of pedaling style, and (depending on placement of sensors) avoiding the need to replace bike components. No commercial system using this technique is available yet for use outside a laboratory although at least two (Brim Brothers and MetriGear) have been announced as in development.
Manufacturers
SRM Training System, a torque-measuring crankset
PowerTap, a torque-measuring hub that is built into a wheel
Polar S-710i or CS600, uses a chain vibration sensor that mounts on the right chainstay
iBike Pro, a handle-bar mounted power meter that measures the cyclist's output by measuring opposing forces
Quarq, a torque measuring device that mounts on the crankset spider
Brim Brothers, a force measuring system fitted in the cleat on the cyclist's shoe
MetriGear, integrated into the hollow spindle of stock bicycle pedals.
See also
Bicycle performance
References
^ http://www.thisisant.com/pages/ant/interoperability-matrix
External links
Book: Training and Racing with a Power Meter
Comprehensive Power Meter Review
Power: The Ultimate Training Metric
Power Meter Project 2007
Wattage Google Group (membership required, but free to join)
Watts Per Kilogram - Improving Cycling Performance
Categories: Bicycle parts
Kempele
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History
First permanent inhabitants settled in Kempele area approximately 500 years ago at that time coast line was closer than what it is today. Kempele was part of Greater Liminka and consisted only of three houses in 1568 when the area was called as Kempele first time in official context. Full church privileges were granted to Kempele in 1774, which also meant separation from Liminka. Municipality administration was established in 1867.
Sights large clitoris
The old wooden church was built between 16881691. hooded leather
The old wooden church of Kempele, which was built in late 17th century, is one of the oldest wooden churches in Finland. Originally Kempele was granted rights to build up a praying room in 1688, but local parishioners decided to construct a church with steeple. As it was typical at that time to bury local notable persons under the church building, also in Kempele there are approximately 150 graves last of them from 1796. double ended dildo
Even though the old church is not anymore in active use after the new one was build next to it in 1990s, some activities are still kept in there.
Kempele may be best known, however, for being the headquarters of the world-famous heart rate monitor corporation, Polar Electro, which first innovated this product in 1978.
References
^ "Area by municipality as of 1 January 2009" (in Finnish and Swedish) (PDF). Land Survey of Finland. http://www.maanmittauslaitos.fi/Pintaalat_kunnittain_1.1.2009.pdf. Retrieved 20 February 2009.
^ "Population by municipality as of 31 December 2009" (in Finnish and Swedish). Population Information System. Population Register Center of Finland. http://www.vrk.fi/vrk/files.nsf/files/4AD425C09E8E9093C22576AA001D7112/$file/091231.htm. Retrieved 13 January 2010.
^ "Population according to language and the number of foreigners and land area km2 by area as of 31 December 2008". Statistics Finland's PX-Web databases. Statistics Finland. http://pxweb2.stat.fi/Dialog/varval.asp?ma=060_vaerak_tau_107_fi&ti=V%E4est%F6+kielen+mukaan+sek%E4+ulkomaan+kansalaisten+m%E4%E4r%E4+ja+maa%2Dpinta%2Dala+alueittain++1980+%2D+2008&path=../Database/StatFin/vrm/vaerak/&lang=3&multilang=fi. Retrieved 29 March 2009.
^ "Population according to age and gender by area as of 31 December 2008". Statistics Finland's PX-Web databases. Statistics Finland. http://pxweb2.stat.fi/Dialog/varval.asp?ma=050_vaerak_tau_104_fi&ti=V%E4est%F6+i%E4n+%281%2Dv%2E%29+ja+sukupuolen+mukaan+alueittain+1980+%2D+2008&path=../Database/StatFin/vrm/vaerak/&lang=3&multilang=fi. Retrieved 28 April 2009.
^ "List of municipal and parish tax rates in 2010". Tax Administration of Finland. 24 November 2009. http://www.vero.fi/download.asp?id=5853;25512. Retrieved 13 January 2010.
External links
Media related to Kempele at Wikimedia Commons
Municipality of Kempele
Map of Kempele
v d e
Municipalities of Northern Ostrobothnia
Municipalities
Alavieska Haapajrvi Haapavesi Hailuoto Haukipudas Ii Kalajoki Kempele Kiiminki Kuusamo Krsmki Liminka Lumijoki Merijrvi Muhos Nivala Oulainen Oulu Oulunsalo Pudasjrvi Pyhjoki Pyhjrvi Pyhnt Raahe Reisjrvi Sievi Siikajoki Siikalatva Taivalkoski Tyrnv Utajrvi Vihanti Yli-Ii Ylivieska
Former municipalities
Kestil Kuivaniemi Oulujoki Paavola Pattijoki Piippola Pulkkila Rantsila Rautio Revonlahti Ruukki Saloinen Temmes Ylikiiminki
Northern Ostrobothnia Finland
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Categories: Municipalities of Northern Ostrobothnia Region | Settlements established in 1867 | Oulu Province geography stubsHidden categories: Articles containing Finnish language text
AMD K6
China Suppliers
Background
The AMD K6 architecture.
The AMD K6 is a superscalar Pentium-class microprocessor, manufactured by AMD, which superseded the K5. It was co-developed by Vinod Dham, lead designer of the Intel P5 microarchitecture. The AMD K6 is based on the Nx686 microprocessor that NexGen was designing when it was acquired by AMD. Despite the name implying a design evolving from the K5, it is in fact a totally different design that was created by the NexGen team and adapted after the AMD purchase. The K6 processor included a feedback dynamic instruction reordering mechanism, MMX instructions, and a floating-point unit (FPU). It was also made pin-compatible with Intel's Pentium, enabling it to be used in the widely available "Socket 7"-based motherboards. Like the Nx686 and Nx586 before it, the K6 translated the Pentium compatible x86 instruction set to RISC-like micro-instructions. A later variation of the K6 CPU, K6-2, added floating point-based SIMD instructions, called 3DNow!. microsoft trackball mouse
The K6 was originally launched in April 1997, running at speeds of 166 and 200 MHz. It was followed by a 233 MHz version later in 1997. Initially, the AMD K6 processors used a Pentium II-based performance rating (PR2) to designate their speed. The PR2 rating was dropped because the rated frequency of the processor was the same as the real frequency. The release of the 266 MHz version of this chip was not until the second quarter of 1998 when AMD was able to move to the 0.25 micrometre manufacturing process. The lower voltage and higher multiplier of the K6-266 meant that it was not 100% compatible with some Socket 7 motherboards, similar to the later K6-2 processors. The final iteration of the K6 design was released in May 1998 running at 300 MHz. ergonomic computer mouse
Many viewed the K6 and the acquisition of NexGen as the moment that AMD was put back into the Intel compatible processor market. The actual K6 AMD had been designing was anemic compared to NexGen's design. With the buyout of NexGen, AMD was able to come back into the game with a processor that could perform competitively with Intel's Pentium II. rechargeable wireless mouse
Models
Original K6 (Model 6)
K6 "Little Foot" (Model 7)
K6 (Model 6)
8.8 million transistors in 350 nm
L1-Cache: 32 + 32 KB (Data + Instructions)
MMX
Socket 7
Front side bus: 66 MHz
First release: April 2, 1997
VCore: 2.9 V (166/200) 3.2/3.3 V (233)
Clockrate: 166, 200, 233 MHz
K6 "Little Foot" (Model 7)
CPUID: Family 5, Model 7, Stepping 0
8.8 million transistors in 250 nm
L1-Cache: 32 + 32 KB (Data + Instructions)
MMX
Socket 7
Front side bus: 66 MHz
First release: January 6, 1998
VCore: 2.2 V
Clockrate: 200, 233, 266, 300 MHz
References
Further reading
Gwennap, Linley (31 March 1997). "K6 Is World's Fastest x86 Chip". Microprocessor Report.
Slater, Michael (28 October 1998). "K6 to Boost AMD's Position in 1997". Microprocessor Report.
External links
AMD: Mobile AMD-K6 Processor
Intel's Enemy No. 1: The AMD K6 CPU
AMD K6, first of an impressive dynasty
Technical overview of the AMD-K6 series
Pictures of AMD-K6 chips at CPUShack.com
AMD K6 technical specifications
technical dissection of the 6th generation x86 CPUs
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AMD processors
Discontinued
Am2900 Am29000 Am9080 Am286 Am386 Am486 Am5x86 K5 K6 K6-2 K6-III Duron Athlon Mobile Athlon 64 Alchemy
Current
Geode Sempron Athlon 64 (Athlon Neo) Athlon X2 Phenom (Phenom II) Athlon II Turion Opteron
Future
Fusion (Bulldozer Bobcat)
Microarchitectures
K7 K8 K9 K10
Lists
Am2900 Duron Athlon Athlon XP Sempron Athlon 64 Athlon X2 Phenom Turion Opteron Future Microprocessors
Instruction sets
3DNow! SSE4a XOP FMA4 CVT16
Categories: 1997 introductions | Advanced Micro Devices x86 microprocessorsHidden categories: Wikipedia articles incorporating text from FOLDOC | Articles lacking in-text citations from February 2008 | All articles lacking in-text citations