Sunday, October 26, 2008
Wednesday, October 22, 2008
So I don't know what to say, but MIT has most of it's courses free, online, and open-source.
Even with occasional notes and video aids from the instructors.
I'm so excited, I was going to be adding my sketch book into an old physics notes book -oddly enough it's really similar to the one that they now sell in the Art Cellar.....
so look at this MIT Courses Cataloged Online
pretty awesome right?
I really really like that stuff. AND i can get an MIT physics education now, I mean, what's a BFA gonna do? Put me more in debt? Now I have a way to pay this art shit off.
Even with occasional notes and video aids from the instructors.
I'm so excited, I was going to be adding my sketch book into an old physics notes book -oddly enough it's really similar to the one that they now sell in the Art Cellar.....
so look at this MIT Courses Cataloged Online
pretty awesome right?
I really really like that stuff. AND i can get an MIT physics education now, I mean, what's a BFA gonna do? Put me more in debt? Now I have a way to pay this art shit off.
check out Star Trek - it's awesome
go to Memory Alpha
it's a Star Trek wiki -
That's what the first page says about the site.
I think that the aesthetic of star trek is the most awesome thing ever really. Conduits? Cycborgs? Aliens? Computers that talk to you? so good
go to Memory Alpha
it's a Star Trek wiki -
Memory Alpha is a collaborative project to create the most definitive, accurate, and accessible encyclopedia and reference for everything related to Star Trek. The English-language Memory Alpha started in November 2003, and currently consists of 29,191 articles.
That's what the first page says about the site.
I think that the aesthetic of star trek is the most awesome thing ever really. Conduits? Cycborgs? Aliens? Computers that talk to you? so good
Wednesday, October 15, 2008
Tuesday, October 14, 2008
Satellite Studying the Sun Is Falling Out of Orbit
By JOHN NOBLE WILFORD
There will be no saving Solar Max this time.
The three-ton spacecraft, known formally as the Solar Maximum Mission satellite, is slowly but inexorably falling out of orbit, descending at a rate of more than half a mile a day.
It is now predicted to come crashing into the atmosphere as early as Nov. 29.
Although nearly all of the craft should burn up in the upper atmosphere, some fragments could survive re-entry and fall on equatorial regions of the world. The National Aeronautics and Space Administration says any debris would most likely fall in the ocean and so should not pose a serious threat to populated areas.
A more exact prediction of the time and place of the satellite's fiery plunge will not be possible until an hour or two before it is to occur. Was Captured and Repaired
In trouble once before, Solar Max in 1984 became the first craft to be captured and repaired in space by shuttle astronauts. The craft was left in a higher orbit for almost six more years of fruitful observations of the Sun. But the space agency turned down scientists who pleaded late last year for another rescue mission by astronauts and decided to let the laws of gravity take their course.
The decision underscored the limitations on the availability of the shuttles to handle important missions. Given the large backlog of shuttle payloads, a consequence of the Challenger disaster in 1986, NASA officials could not squeeze in a second Solar Max rescue without causing further expensive delays for science missions with higher priority.
''The final decision, after two years of agonizing over it, was to say no to Solar Max, even though it's been a super spacecraft,'' said Charles Redmond, a NASA spokesman in Washington.
The distress of another spacecraft in orbit influenced the decision. The 11-ton Long Duration Exposure Facility, or LDEF, is also losing altitude rapidly and must be recovered, if at all, no later than February. The big satellite, placed in orbit in 1984 by the same shuttle crew that repaired Solar Max, is an inert platform carrying samples of electronics, metals, plastics and other materials to determine how they hold up when exposed for a long time to cosmic rays, solar radiation and micrometeorites.
The platform was originally supposed to be brought back to Earth for examination after a year in orbit. That retrieval by a shuttle was postponed for scheduling reasons and then put off indefinitely when the Challenger exploded shortly after liftoff Jan. 28, 1986, killing all seven crew members. Considered More Worthy
''A lot of us would have liked to go and get Solar Max, refurbish it on the ground and relaunch it,'' said Dr. Dale W. Harris, the deputy director for flight projects at the Goddard Space Flight Center in Greenbelt, Md. ''But if there could be only one rescue mission, it was thought that getting the data from LDEF was more worthwhile.''
Space agency engineers argued forcefully that the platform's 57 experiments in material endurance were crucial for the design of the $30 billion space station, which is supposed to have an orbital lifetime of three decades. Officials of the Pentagon's Strategic Defense Initiative wanted to examine the platform to learn how to insure the long endurance of space-based antimissile weapons.
As a result, astronauts in late December are scheduled to fly the space shuttle Columbia to a rendezvous with the big satellite, grab it with the shuttle's long mechanical arm and haul it into the cargo bay for a return to Earth. The mission is tentatively set for liftoff on Dec. 18.
Both the big satellite and Solar Max - indeed, all spacecraft in low Earth orbits -are being buffeted by the effects of the Sun as it reaches a peak of turbulent activity that occurs every 11 years. Scientists at the National Oceanic and Atmospheric Administration said ''unprecedented high levels of solar activity'' began last March and this was undoubtedly reducing the operational life of some spacecraft. It is just such solar activity that Solar Max was designed to study.
Dr. Joseph Gurman, the chief Solar Max scientist at the Goddard center, said the primary effect on spacecraft comes indirectly from the Sun's enhanced emissions of ultraviolet radiation at times of peak sunspot activity, a period know as the solar maximum. The increased ultraviolet radiation heats Earth's upper atmosphere, causing it to expand outward.
Even in the most placid of solar times, enough atmospheric molecules reach the altitudes where they cause some friction against Earth-orbiting spacecraft. The drag tends to pull a craft down a few miles each year, unless it is equipped with propulsion systems capable of regaining altitude. In the last few months, the ultraviolet emissions have risen sharply, and spacecraft are now encountering more atmospheric friction. Frequent Magnetic Eruptions
In addition, magnetic eruptions on the Sun are occurring more frequently during solar maximum and producing intense solar flares. The flares bring a rain of high-energy particles that produce communications-disrupting magnetic storms and auroras in the Earth's atmosphere. The increase in magnetic and particle activity in Earth's vicinity acts as a brief but even stronger drag on orbiting craft. Within two days of a solar flare last month, Solar Max's rate of descent went from a half-mile a day to more than one mile.
''I guess the flare hurried things up,'' Dr. Harris said, explaining the change of the spacecraft's predicted demise from mid-December to Dec. 3, by some calculations, or Nov. 29, by others.
According to studies conducted for NASA, several pieces of Solar Max, weighing from 25 to 400 pounds, could survive the re-entry and reach the Earth's surface. The debris could strike anywhere between 28 degrees north latitude and 28 degrees south, which is the part of the world over which Solar Max is traveling. More than 75 percent of the area is water, Dr. Harris said, but it also includes parts of Africa, South America, India, Southeast Asia and Australia. The only parts of the United States at any risk are Hawaii, southern Florida and the southern tip of Texas.
''The probability of doing damage is very, very small,'' Dr. Harris said.
If the LDEF platform is not retrieved, it could rain even more debris on Earth. But neither it nor Solar Max is considered as great a hazard as the Skylab space station, which weighed nearly 100 tons and came down 10 years ago. Fragments hit the Indian Ocean and some remote areas of Australia, but caused no known injuries or serious property damage. No Propulsion System
Dr. Harris said Solar Max has no propulsion system so cannot be raised to a higher orbit or aimed for a re-entry point avoiding land. Engineers will not have any communications with the craft in its final days, as it tumbles out of control and loses its antenna lock on Earth. Radar tracking observations should provide an hour or two of advance warning of the craft's plunge.
Solar Max was originally lofted by a rocket into a 356-mile-high orbit in 1980. But it was designed to be serviced by the shuttle, and so in 1984 the astronauts replaced some failed components and left the craft 310 miles in orbit. It is now down to 190 miles. By the time it descends to less than 180 miles, engineers figure, Solar Max is likely begin its fiery plunge.
Solar Max continues to return data on the Sun, including observations of the recent flares and the collision of a comet into the Sun in September. Engineers are also extracting measurements on the spacecraft's performance for use in future designs.
As much as he and other solar physicists regret the impending loss, Dr. Gurman said Solar Max had returned data for almost 10 years, just short of a full solar cycle, and Japan, the European Space Agency and the United States have plans for more ambitious spacecraft missions to study the Sun in the next decade.
Mission planners at the Johnson Space Center in Houston are making a careful study of the other endangered spacecraft, LDEF, as they plot the maneuvers necessary for the space shuttle to find and retrieve the craft. Al Pennington, a flight director, said the platform had descended from its original altitude of 290 miles to 232 miles and is predicted to be at 210 miles when the rescue mission is launched.
Because of the rapidly changing position of the spacecraft, Brian D. Welch, a spokesman at the Johnson center, said flight controllers would be making ''exquisite refinements'' in the rendezvous strategy up to the day and hour of liftoff.
- taken from The New York Times
By JOHN NOBLE WILFORD
There will be no saving Solar Max this time.
The three-ton spacecraft, known formally as the Solar Maximum Mission satellite, is slowly but inexorably falling out of orbit, descending at a rate of more than half a mile a day.
It is now predicted to come crashing into the atmosphere as early as Nov. 29.
Although nearly all of the craft should burn up in the upper atmosphere, some fragments could survive re-entry and fall on equatorial regions of the world. The National Aeronautics and Space Administration says any debris would most likely fall in the ocean and so should not pose a serious threat to populated areas.
A more exact prediction of the time and place of the satellite's fiery plunge will not be possible until an hour or two before it is to occur. Was Captured and Repaired
In trouble once before, Solar Max in 1984 became the first craft to be captured and repaired in space by shuttle astronauts. The craft was left in a higher orbit for almost six more years of fruitful observations of the Sun. But the space agency turned down scientists who pleaded late last year for another rescue mission by astronauts and decided to let the laws of gravity take their course.
The decision underscored the limitations on the availability of the shuttles to handle important missions. Given the large backlog of shuttle payloads, a consequence of the Challenger disaster in 1986, NASA officials could not squeeze in a second Solar Max rescue without causing further expensive delays for science missions with higher priority.
''The final decision, after two years of agonizing over it, was to say no to Solar Max, even though it's been a super spacecraft,'' said Charles Redmond, a NASA spokesman in Washington.
The distress of another spacecraft in orbit influenced the decision. The 11-ton Long Duration Exposure Facility, or LDEF, is also losing altitude rapidly and must be recovered, if at all, no later than February. The big satellite, placed in orbit in 1984 by the same shuttle crew that repaired Solar Max, is an inert platform carrying samples of electronics, metals, plastics and other materials to determine how they hold up when exposed for a long time to cosmic rays, solar radiation and micrometeorites.
The platform was originally supposed to be brought back to Earth for examination after a year in orbit. That retrieval by a shuttle was postponed for scheduling reasons and then put off indefinitely when the Challenger exploded shortly after liftoff Jan. 28, 1986, killing all seven crew members. Considered More Worthy
''A lot of us would have liked to go and get Solar Max, refurbish it on the ground and relaunch it,'' said Dr. Dale W. Harris, the deputy director for flight projects at the Goddard Space Flight Center in Greenbelt, Md. ''But if there could be only one rescue mission, it was thought that getting the data from LDEF was more worthwhile.''
Space agency engineers argued forcefully that the platform's 57 experiments in material endurance were crucial for the design of the $30 billion space station, which is supposed to have an orbital lifetime of three decades. Officials of the Pentagon's Strategic Defense Initiative wanted to examine the platform to learn how to insure the long endurance of space-based antimissile weapons.
As a result, astronauts in late December are scheduled to fly the space shuttle Columbia to a rendezvous with the big satellite, grab it with the shuttle's long mechanical arm and haul it into the cargo bay for a return to Earth. The mission is tentatively set for liftoff on Dec. 18.
Both the big satellite and Solar Max - indeed, all spacecraft in low Earth orbits -are being buffeted by the effects of the Sun as it reaches a peak of turbulent activity that occurs every 11 years. Scientists at the National Oceanic and Atmospheric Administration said ''unprecedented high levels of solar activity'' began last March and this was undoubtedly reducing the operational life of some spacecraft. It is just such solar activity that Solar Max was designed to study.
Dr. Joseph Gurman, the chief Solar Max scientist at the Goddard center, said the primary effect on spacecraft comes indirectly from the Sun's enhanced emissions of ultraviolet radiation at times of peak sunspot activity, a period know as the solar maximum. The increased ultraviolet radiation heats Earth's upper atmosphere, causing it to expand outward.
Even in the most placid of solar times, enough atmospheric molecules reach the altitudes where they cause some friction against Earth-orbiting spacecraft. The drag tends to pull a craft down a few miles each year, unless it is equipped with propulsion systems capable of regaining altitude. In the last few months, the ultraviolet emissions have risen sharply, and spacecraft are now encountering more atmospheric friction. Frequent Magnetic Eruptions
In addition, magnetic eruptions on the Sun are occurring more frequently during solar maximum and producing intense solar flares. The flares bring a rain of high-energy particles that produce communications-disrupting magnetic storms and auroras in the Earth's atmosphere. The increase in magnetic and particle activity in Earth's vicinity acts as a brief but even stronger drag on orbiting craft. Within two days of a solar flare last month, Solar Max's rate of descent went from a half-mile a day to more than one mile.
''I guess the flare hurried things up,'' Dr. Harris said, explaining the change of the spacecraft's predicted demise from mid-December to Dec. 3, by some calculations, or Nov. 29, by others.
According to studies conducted for NASA, several pieces of Solar Max, weighing from 25 to 400 pounds, could survive the re-entry and reach the Earth's surface. The debris could strike anywhere between 28 degrees north latitude and 28 degrees south, which is the part of the world over which Solar Max is traveling. More than 75 percent of the area is water, Dr. Harris said, but it also includes parts of Africa, South America, India, Southeast Asia and Australia. The only parts of the United States at any risk are Hawaii, southern Florida and the southern tip of Texas.
''The probability of doing damage is very, very small,'' Dr. Harris said.
If the LDEF platform is not retrieved, it could rain even more debris on Earth. But neither it nor Solar Max is considered as great a hazard as the Skylab space station, which weighed nearly 100 tons and came down 10 years ago. Fragments hit the Indian Ocean and some remote areas of Australia, but caused no known injuries or serious property damage. No Propulsion System
Dr. Harris said Solar Max has no propulsion system so cannot be raised to a higher orbit or aimed for a re-entry point avoiding land. Engineers will not have any communications with the craft in its final days, as it tumbles out of control and loses its antenna lock on Earth. Radar tracking observations should provide an hour or two of advance warning of the craft's plunge.
Solar Max was originally lofted by a rocket into a 356-mile-high orbit in 1980. But it was designed to be serviced by the shuttle, and so in 1984 the astronauts replaced some failed components and left the craft 310 miles in orbit. It is now down to 190 miles. By the time it descends to less than 180 miles, engineers figure, Solar Max is likely begin its fiery plunge.
Solar Max continues to return data on the Sun, including observations of the recent flares and the collision of a comet into the Sun in September. Engineers are also extracting measurements on the spacecraft's performance for use in future designs.
As much as he and other solar physicists regret the impending loss, Dr. Gurman said Solar Max had returned data for almost 10 years, just short of a full solar cycle, and Japan, the European Space Agency and the United States have plans for more ambitious spacecraft missions to study the Sun in the next decade.
Mission planners at the Johnson Space Center in Houston are making a careful study of the other endangered spacecraft, LDEF, as they plot the maneuvers necessary for the space shuttle to find and retrieve the craft. Al Pennington, a flight director, said the platform had descended from its original altitude of 290 miles to 232 miles and is predicted to be at 210 miles when the rescue mission is launched.
Because of the rapidly changing position of the spacecraft, Brian D. Welch, a spokesman at the Johnson center, said flight controllers would be making ''exquisite refinements'' in the rendezvous strategy up to the day and hour of liftoff.
- taken from The New York Times
Friday, October 3, 2008
it's been a while since i posted last, but i've been busy a silly amount
i really like this stuff, it's been bookmarked on my computer for a while now, i really like the both of them, even though they're just wikipedia pages
http://en.wikipedia.org/wiki/Spaceflight
http://en.wikipedia.org/wiki/Rocket
and then there's this stuff, I'll see if I can post some images from here that seem appropriate
One of the most amazing endeavors man has ever undertaken is the exploration of space. A big p art of the amazement is the complexity. Space exploration is complicated because there are so many problems to solve and obstacles to overcome. You have things like:
The vacuum of space
Heat management problems
The difficulty of re-entry
Orbital mechanics
Micrometeorites and space debris
Cosmic and solar radiation
The logistics of having restroom facilities in a weightless environment
But the biggest problem of all is harnessing enough energy simply to get a spaceship off the ground. That is where rocket engines come in
Rocket engines are, on the one hand, so simple that you can build and fly your own model rockets very inexpensively (see the links on the last page of the article for details). On the other hand, rocket engines (and their fuel systems) are so complicated that only three countries have actually ever put people in orbit. In this article, we will look at rocket engines to understand how they work, as well as to understand some of the complexity surrounding them.
When most people think about motors or engines, they think about rotation. For example, a reciprocating gasoline engine in a car produces rotational energy to drive the wheels. An electric motor produces rotational energy to drive a fan or spin a disk. A steam engine is used to do the same thing, as is a steam turbine and most gas turbines.
Rocket engines are fundamentally different. Rocket engines are reaction engines. The basic principle driving a rocket engine is the famous Newtonian principle that "to every action there is an equal and opposite reaction." A rocket engine is throwing mass in one direction and benefiting from the reaction that occurs in the other direction as a result.
This concept of "throwing mass and benefiting from the reaction" can be hard to grasp at first, because that does not seem to be what is happening. Rocket engines seem to be about flames and noise and pressure, not "throwing things." Let's look at a few examples to get a better picture of reality:
If you have ever shot a shotgun, especially a big 12-gauge shotgun, then you know that it has a lot of "kick." That is, when you shoot the gun it "kicks" your shoulder back with a great deal of force. That kick is a reaction. A shotgun is shooting about an ounce of metal in one direction at about 700 miles per hour, and your shoulder gets hit with the reaction. If you were wearing roller skates or standing on a skateboard when you shot the gun, then the gun would be acting like a rocket engine and you would react by rolling in the opposite direction.
If you have ever seen a big fire hose spraying water, you may have noticed that it takes a lot of strength to hold the hose (sometimes you will see two or three firefighters holding the hose). The hose is acting like a rocket engine. The hose is throwing water in one direction, and the firefighters are using their strength and weight to counteract the reaction. If they were to let go of the hose, it would thrash around with tremendous force. If the firefighters were all standing on skateboards, the hose would propel them backward at great speed!
When you blow up a balloon and let it go so that it flies all over the room before running out of air, you have created a rocket engine. In this case, what is being thrown is the air molecules inside the balloon. Many people believe that air molecules don't weigh anything, but they do (see the page on helium to get a better picture of the weight of air). When you throw them out the nozzle of a balloon, the rest of the balloon reacts in the opposite direction.
that was taken from http://www.howstuffworks.com/rocket.htm
i really like this stuff, it's been bookmarked on my computer for a while now, i really like the both of them, even though they're just wikipedia pages
http://en.wikipedia.org/wiki/Spaceflight
http://en.wikipedia.org/wiki/Rocket
and then there's this stuff, I'll see if I can post some images from here that seem appropriate
One of the most amazing endeavors man has ever undertaken is the exploration of space. A big p art of the amazement is the complexity. Space exploration is complicated because there are so many problems to solve and obstacles to overcome. You have things like:
The vacuum of space
Heat management problems
The difficulty of re-entry
Orbital mechanics
Micrometeorites and space debris
Cosmic and solar radiation
The logistics of having restroom facilities in a weightless environment
But the biggest problem of all is harnessing enough energy simply to get a spaceship off the ground. That is where rocket engines come in
Rocket engines are, on the one hand, so simple that you can build and fly your own model rockets very inexpensively (see the links on the last page of the article for details). On the other hand, rocket engines (and their fuel systems) are so complicated that only three countries have actually ever put people in orbit. In this article, we will look at rocket engines to understand how they work, as well as to understand some of the complexity surrounding them.
When most people think about motors or engines, they think about rotation. For example, a reciprocating gasoline engine in a car produces rotational energy to drive the wheels. An electric motor produces rotational energy to drive a fan or spin a disk. A steam engine is used to do the same thing, as is a steam turbine and most gas turbines.
Rocket engines are fundamentally different. Rocket engines are reaction engines. The basic principle driving a rocket engine is the famous Newtonian principle that "to every action there is an equal and opposite reaction." A rocket engine is throwing mass in one direction and benefiting from the reaction that occurs in the other direction as a result.
This concept of "throwing mass and benefiting from the reaction" can be hard to grasp at first, because that does not seem to be what is happening. Rocket engines seem to be about flames and noise and pressure, not "throwing things." Let's look at a few examples to get a better picture of reality:
If you have ever shot a shotgun, especially a big 12-gauge shotgun, then you know that it has a lot of "kick." That is, when you shoot the gun it "kicks" your shoulder back with a great deal of force. That kick is a reaction. A shotgun is shooting about an ounce of metal in one direction at about 700 miles per hour, and your shoulder gets hit with the reaction. If you were wearing roller skates or standing on a skateboard when you shot the gun, then the gun would be acting like a rocket engine and you would react by rolling in the opposite direction.
If you have ever seen a big fire hose spraying water, you may have noticed that it takes a lot of strength to hold the hose (sometimes you will see two or three firefighters holding the hose). The hose is acting like a rocket engine. The hose is throwing water in one direction, and the firefighters are using their strength and weight to counteract the reaction. If they were to let go of the hose, it would thrash around with tremendous force. If the firefighters were all standing on skateboards, the hose would propel them backward at great speed!
When you blow up a balloon and let it go so that it flies all over the room before running out of air, you have created a rocket engine. In this case, what is being thrown is the air molecules inside the balloon. Many people believe that air molecules don't weigh anything, but they do (see the page on helium to get a better picture of the weight of air). When you throw them out the nozzle of a balloon, the rest of the balloon reacts in the opposite direction.
that was taken from http://www.howstuffworks.com/rocket.htm
Friday, September 5, 2008
BRONZE SCULPTURE: THE ART OF LOST WAX
In the third millennium B.C., somewhere between the Black Sea and the Persian Gulf, an artist crafted a vision in beeswax, covered it in liquid clay and cooked it in a fire. In the flames the wax was lost, replaced by empty space. Tin and copper - alloys of bronze – were gathered and heated. Once melted, the metal was poured into the cavity of the fire-hardened clay. The metal cooled and the sculptor knocked the clay from the metal. The first bronze was cast.
Ancient "Lost Wax" bronze castings have withstood the centuries, visually telling the tale of past cultures, their religions and their social structures. For example: Chinese bronzes often depicted ceremonial imagery, Indian and Egyptian castings frequently represented deities, the Africans cast images of nature, and the Greeks re-created the human Form. Many of these cultures have grown obsolete, religions have evolved and societies have changed, but an intriguing visual history survives through the surviving bronze works. Certain elements of the "Lost Wax" process have indeed been refined, yet today bronze casting remains essentially the same as it was in 2,000 BC during the Akkadian period.
Modern sculptors who want their pieces cast in bronze depend upon a foundry. There, artisans skillfully apply the "Lost Wax" method to wood, stone, clay, plaster and essentially any other form of sculpture to transform the artist’s vision into bronze.
THE RUBBER MOLD
The metamorphosis of a sculpture from the original medium into bronze begins with a rubber mold. The original sculpture must remain stationary during the mold making process. To accomplish this, half of the sculpture is nestled into a base of soft plasticine clay; the other exposed half is painted evenly with a clear, viscous rubber. (Polyurethane rubber is best for single or small editions while larger editions require silicone rubber.) When the half painted with rubber dries, a protective and rock hard "mother mold" made of reinforced plaster is built around the pliable rubber. The sculpture is then turned over, and the process repeated. When the second side is complete, the mold is opened and the original removed from within. The rubber is rejoined with the other half, rendering an exact "negative" image of the sculpture in rubber. The mold is often done in several sections to facilitate proper and even flow during the actual bronze pour.
THE WAX POSITIVE
The original sculpture is now used exclusively as a reference point. From the "negative" rubber mold, a wax "positive" must be created. Wax is melted to about 210°F, poured into the mold and evenly coated or "slushed" inside. Slushing is repeated three times using cooler wax each time to avoid melting the previous coat. Under ideal conditions, the wax wall will be about 3/16" thick --- any less might create flow problems for the bronze; any more will result in a heavier than necessary sculpture. When the mold is opened and the rubber peeled away, an almost perfect wax reproduction is removed.
WAX CHASING · SPRUING & GATING
"Wax chasing" is the delicate process of joining the wax pieces back together to form a complete “positive” of the sculpture (including removing seams and repairing imperfections with heated customized soldering irons or tools: dental tools being ideal). Artists are very involved at this juncture, checking the integrity of the wax and, after approving it, signing the piece.
After the wax is chased and approved by the artist, the piece is then advanced to "Spruing" or "Gating." This is where channels, through which the molten bronze will travel to the artwork, are added to the wax version. These channels are also made of wax.
"Vents" (thin wax sticks) and "Gates" (thicker wax sticks) are affixed to the wax reproduction with heated tools. Later in the casting process, the space occupied by sprues or gates become runways through which the metal flows and trapped gas escapes. Distribution of the bronze, low turbulence, ventilation and shrinkage are important considerations in the science of gating and spruing.
INVESTING
"Investment" is the process of building a rock-hard shell around the wax sculpture. Later in the process, when the wax has been melted out, the investment will serve as a mold for the molten bronze. For most of history, an investment consisting of plaster, sand and water was used to accomplish this task. In the last 15 years, a new technology called ceramic shell has become the industry standard.
The ceramic shell technique begins by dipping the gated wax into vats of slurry followed immediately by a bath of sand. This process builds a very thin wall of silica around the wax. When repeated approximately 9 times, allowing for drying time in between dips, a hard ceramic shell, about ½" thick, forms around the wax.
Prior to the invention of ceramic shell, solid plaster investment was used. To invest by the solid plaster method: tarpaper was loosely wrapped around the wax reproduction in the shape of a cylinder. The enclosed space surrounding the wax was then filled with a wet plaster/sand mixture. When the plaster hardened, the tarpaper was removed and a solid plaster investment is ready for "de-wax." Whether ceramic shell or plaster is used to make the shell, the wax is a "positive" which must disappear in order to create a cavity or "negative" for the bronze to fill. Thus the phrase "lost wax casting" comes from the process of the wax being melted or "lost" from the shell. Plaster built shells are "de-waxed" in a high-pressure steam chamber known as an autoclave; ceramic invested shells are de-waxed in a kiln.
THE POUR
A huge graphite crucible, fired by a furnace, is filled with bronze ingots that are melted. The metal begins to melt at 1700°F. Bronze "seizes" (stops flowing) when confronted with cold, which might occur if molten bronze was poured into a room temperature shell; therefore at the same time the bronze is being blasted by a natural gas furnace, the ceramic shell is heated in a kiln to approximately 1100°F.
When the "Dance of the Pour" begins, the crucible is lifted by crane out of the gas furnace. At the same time, the glowing ceramic shells are brought out of the kiln to the pour area. Two artisans operate the crane that holds the crucible in a "jacket." The artisan with the controls is the "lead pour," the artisan maintaining the crucible balance is known as the "deadman." A third member of the pour team pushes away dross and slag on the surface of the molten bronze.
The entire pour is very fast and very precise; one crucible of bronze holds 400 lbs and can fill one or two large shells or ten or more small shells. The first pieces poured are those with thin walls and intricate details; requiring hot, fluid bronze to move throughout the channel system. The alloy cast at Artworks is known as Silicon Bronze. The metal is made up of the following elements: COPPER 94.0%, MANGANESE 1.1%, SILICON 3.9%, TRACE ELEMENTS 1.0%. Silicon is an additive that helps the "flowability" of the bronze. It achieved widespread use during World War II when lead and tin were in short supply.
DEVESTING
"Devesting" is the process during which the investment is removed from the metal. Approximately one hour after the pour, the piece is cool enough to handle. Skill and strength are combined with hammers and power chisels to knock the investment off the freshly solidified metal. The gates and sprues must also be removed with a high intensity electric arc that can cut through the bronze like butter. The final step is to sandblast the fine investment from the bronze. When clean, the sculpture advances to the metal shop…
In the third millennium B.C., somewhere between the Black Sea and the Persian Gulf, an artist crafted a vision in beeswax, covered it in liquid clay and cooked it in a fire. In the flames the wax was lost, replaced by empty space. Tin and copper - alloys of bronze – were gathered and heated. Once melted, the metal was poured into the cavity of the fire-hardened clay. The metal cooled and the sculptor knocked the clay from the metal. The first bronze was cast.
Ancient "Lost Wax" bronze castings have withstood the centuries, visually telling the tale of past cultures, their religions and their social structures. For example: Chinese bronzes often depicted ceremonial imagery, Indian and Egyptian castings frequently represented deities, the Africans cast images of nature, and the Greeks re-created the human Form. Many of these cultures have grown obsolete, religions have evolved and societies have changed, but an intriguing visual history survives through the surviving bronze works. Certain elements of the "Lost Wax" process have indeed been refined, yet today bronze casting remains essentially the same as it was in 2,000 BC during the Akkadian period.
Modern sculptors who want their pieces cast in bronze depend upon a foundry. There, artisans skillfully apply the "Lost Wax" method to wood, stone, clay, plaster and essentially any other form of sculpture to transform the artist’s vision into bronze.
THE RUBBER MOLD
The metamorphosis of a sculpture from the original medium into bronze begins with a rubber mold. The original sculpture must remain stationary during the mold making process. To accomplish this, half of the sculpture is nestled into a base of soft plasticine clay; the other exposed half is painted evenly with a clear, viscous rubber. (Polyurethane rubber is best for single or small editions while larger editions require silicone rubber.) When the half painted with rubber dries, a protective and rock hard "mother mold" made of reinforced plaster is built around the pliable rubber. The sculpture is then turned over, and the process repeated. When the second side is complete, the mold is opened and the original removed from within. The rubber is rejoined with the other half, rendering an exact "negative" image of the sculpture in rubber. The mold is often done in several sections to facilitate proper and even flow during the actual bronze pour.
THE WAX POSITIVE
The original sculpture is now used exclusively as a reference point. From the "negative" rubber mold, a wax "positive" must be created. Wax is melted to about 210°F, poured into the mold and evenly coated or "slushed" inside. Slushing is repeated three times using cooler wax each time to avoid melting the previous coat. Under ideal conditions, the wax wall will be about 3/16" thick --- any less might create flow problems for the bronze; any more will result in a heavier than necessary sculpture. When the mold is opened and the rubber peeled away, an almost perfect wax reproduction is removed.
WAX CHASING · SPRUING & GATING
"Wax chasing" is the delicate process of joining the wax pieces back together to form a complete “positive” of the sculpture (including removing seams and repairing imperfections with heated customized soldering irons or tools: dental tools being ideal). Artists are very involved at this juncture, checking the integrity of the wax and, after approving it, signing the piece.
After the wax is chased and approved by the artist, the piece is then advanced to "Spruing" or "Gating." This is where channels, through which the molten bronze will travel to the artwork, are added to the wax version. These channels are also made of wax.
"Vents" (thin wax sticks) and "Gates" (thicker wax sticks) are affixed to the wax reproduction with heated tools. Later in the casting process, the space occupied by sprues or gates become runways through which the metal flows and trapped gas escapes. Distribution of the bronze, low turbulence, ventilation and shrinkage are important considerations in the science of gating and spruing.
INVESTING
"Investment" is the process of building a rock-hard shell around the wax sculpture. Later in the process, when the wax has been melted out, the investment will serve as a mold for the molten bronze. For most of history, an investment consisting of plaster, sand and water was used to accomplish this task. In the last 15 years, a new technology called ceramic shell has become the industry standard.
The ceramic shell technique begins by dipping the gated wax into vats of slurry followed immediately by a bath of sand. This process builds a very thin wall of silica around the wax. When repeated approximately 9 times, allowing for drying time in between dips, a hard ceramic shell, about ½" thick, forms around the wax.
Prior to the invention of ceramic shell, solid plaster investment was used. To invest by the solid plaster method: tarpaper was loosely wrapped around the wax reproduction in the shape of a cylinder. The enclosed space surrounding the wax was then filled with a wet plaster/sand mixture. When the plaster hardened, the tarpaper was removed and a solid plaster investment is ready for "de-wax." Whether ceramic shell or plaster is used to make the shell, the wax is a "positive" which must disappear in order to create a cavity or "negative" for the bronze to fill. Thus the phrase "lost wax casting" comes from the process of the wax being melted or "lost" from the shell. Plaster built shells are "de-waxed" in a high-pressure steam chamber known as an autoclave; ceramic invested shells are de-waxed in a kiln.
THE POUR
A huge graphite crucible, fired by a furnace, is filled with bronze ingots that are melted. The metal begins to melt at 1700°F. Bronze "seizes" (stops flowing) when confronted with cold, which might occur if molten bronze was poured into a room temperature shell; therefore at the same time the bronze is being blasted by a natural gas furnace, the ceramic shell is heated in a kiln to approximately 1100°F.
When the "Dance of the Pour" begins, the crucible is lifted by crane out of the gas furnace. At the same time, the glowing ceramic shells are brought out of the kiln to the pour area. Two artisans operate the crane that holds the crucible in a "jacket." The artisan with the controls is the "lead pour," the artisan maintaining the crucible balance is known as the "deadman." A third member of the pour team pushes away dross and slag on the surface of the molten bronze.
The entire pour is very fast and very precise; one crucible of bronze holds 400 lbs and can fill one or two large shells or ten or more small shells. The first pieces poured are those with thin walls and intricate details; requiring hot, fluid bronze to move throughout the channel system. The alloy cast at Artworks is known as Silicon Bronze. The metal is made up of the following elements: COPPER 94.0%, MANGANESE 1.1%, SILICON 3.9%, TRACE ELEMENTS 1.0%. Silicon is an additive that helps the "flowability" of the bronze. It achieved widespread use during World War II when lead and tin were in short supply.
DEVESTING
"Devesting" is the process during which the investment is removed from the metal. Approximately one hour after the pour, the piece is cool enough to handle. Skill and strength are combined with hammers and power chisels to knock the investment off the freshly solidified metal. The gates and sprues must also be removed with a high intensity electric arc that can cut through the bronze like butter. The final step is to sandblast the fine investment from the bronze. When clean, the sculpture advances to the metal shop…
i took this from http://www.modernsculpture.com/bronze.htm
Friday, August 29, 2008
Thursday, August 28, 2008
So this was found earlier today and I really enjoyed reading it and just thinking about all the possible mistakes that could come up from having lines and conduits misaligned and improperly set up
Spot mistakes before they literally become set in stone on the site
At the very first site at which I worked, an operator could see the guts of the plant from the safety of his control room. Everything was perfectly laid out. Since then, though, I’ve too often seen operators in dark cellars staring at equipment through hazy TV screens. Outside the control room plant pipes and cables were laid out in a disorderly fashion; equipment teardown frequently disturbed the normal flow of the plant.
So, how can plant layout be improved? Here’re a few thoughts on making plant operations smoother — from the beginning. First, identify equipment with poor reliability or likely requiring frequent attention. Next, decide if spares will be inline or from storage; pumps handling a sticky slurry might be an application where inline won’t work. Then, determine the wind direction, the best escape routes and supply requirements such as where to run a railroad spur. Look at parking, etc. Build from the inside out and then the outside in. If a pipe specification exists, establish the line sizes from the P&ID before attempting a layout; choose the smallest diameter and lightest pipe that will do the job but be wary of waterhammer and pressure drop.
Once you’ve rated the equipment for reliability and sized the pipe, it’s time to develop the plot plan — keep it simple. Here’re some ideas for cutting costs:
anchor small equipment to the structure or larger equipment
place equipment on the ground, if possible
install high-maintenance operator-intensive equipment away from high traffic areas
put sampling stations and instruments where operators will be safe
locate the larger equipment and larger pipes and ducts first, then smaller piping and finally conduit, marshalling panels and electrical utilities
create a run for conduit and pipes, usually in the middle of the plant, keeping it above and away from hazardous locations
where possible, construct pipe manifolds and cluster instruments together to maximize serviceability and reduce the number of hazardous (Div. 1) areas
keep pipe and conduit runs as short as possible to avoid problems such as low NPSHA, heat losses and signal interference
for a fire-safe design, put pumps and compressors in areas of good drainage and ventilation, away from critical structures, pipe racks and equipment, and minimize flanges and other leak points
where two-phase flow may exist, avoid rises or allow for traps
put motor control centers as close as possible to control rooms
provide for material storage, for turnarounds, quality assurance, deliveries and routine batch preparation
install air coolers, cooling towers and other equipment affected by heat so as to take advantage of shade and natural cooling, e.g., the wind normally should flow across the packing in a cooling tower
allow for growth in the facility — size the utilities, i.e., electricity, compressed air, steam, heating and ventilation, purge gas, fuel and even sewers and rail spurs, for future expansions.
After the first pass through the design, review the layout with operations and maintenance, together, in the same room. If you regularly use contractors such as riggers and crane companies, ask them to check the drawings for lifting requirements and scaffolding, removal and replacement of major equipment.
Several common mistakes often haunt plant designers. Foremost are those related to pipe racks. Too often, delicate instrument cables are run close above steam piping, parallel to power lines and in places where they are unshielded from the sun. Then, there’re plant expansions. A premium on downtime means that new wires seldom are added to old conduit. This means new wires and new conduit. Good sense dictates filling conduit to a maximum and allowing for future removal and replacement of rotting conduit, terminal strips and pipe. Plan for future tie-ins; one plant had a single shutoff valve in the steam system.
I’ve been burned more than once by designs that are blind to insulation needs. Design engineers ordering tanks frequently forget to allow for insulation lagging of flanges, manways and instruments — sometimes because these requirements aren’t known when the tank was ordered. However, lack of insulation can pose real risks unless the company enforces a safety standard on surface temperature. Operators have been burned to death attempting to squeeze between uninsulated pipe.
Another mistake is not considering the rigging of equipment for installation, now and in the future. Plan for trolleys and anchor points in the layout. I remember one project where lugs hadn’t been installed on some spools of a large ceramic-lined pipe. This oversight helped turn a four-day outage into one lasting 10 days. Another example: a tank to be welded to a structure came with legs.
The goal is to design a layout that improves the operability, safety and production capability of the plant. This requires an understanding of the needs of mechanics, riggers and operators.
taken from http://www.chemicalprocessing.com/articles/2008/068.html
Spot mistakes before they literally become set in stone on the site
At the very first site at which I worked, an operator could see the guts of the plant from the safety of his control room. Everything was perfectly laid out. Since then, though, I’ve too often seen operators in dark cellars staring at equipment through hazy TV screens. Outside the control room plant pipes and cables were laid out in a disorderly fashion; equipment teardown frequently disturbed the normal flow of the plant.
So, how can plant layout be improved? Here’re a few thoughts on making plant operations smoother — from the beginning. First, identify equipment with poor reliability or likely requiring frequent attention. Next, decide if spares will be inline or from storage; pumps handling a sticky slurry might be an application where inline won’t work. Then, determine the wind direction, the best escape routes and supply requirements such as where to run a railroad spur. Look at parking, etc. Build from the inside out and then the outside in. If a pipe specification exists, establish the line sizes from the P&ID before attempting a layout; choose the smallest diameter and lightest pipe that will do the job but be wary of waterhammer and pressure drop.
Once you’ve rated the equipment for reliability and sized the pipe, it’s time to develop the plot plan — keep it simple. Here’re some ideas for cutting costs:
anchor small equipment to the structure or larger equipment
place equipment on the ground, if possible
install high-maintenance operator-intensive equipment away from high traffic areas
put sampling stations and instruments where operators will be safe
locate the larger equipment and larger pipes and ducts first, then smaller piping and finally conduit, marshalling panels and electrical utilities
create a run for conduit and pipes, usually in the middle of the plant, keeping it above and away from hazardous locations
where possible, construct pipe manifolds and cluster instruments together to maximize serviceability and reduce the number of hazardous (Div. 1) areas
keep pipe and conduit runs as short as possible to avoid problems such as low NPSHA, heat losses and signal interference
for a fire-safe design, put pumps and compressors in areas of good drainage and ventilation, away from critical structures, pipe racks and equipment, and minimize flanges and other leak points
where two-phase flow may exist, avoid rises or allow for traps
put motor control centers as close as possible to control rooms
provide for material storage, for turnarounds, quality assurance, deliveries and routine batch preparation
install air coolers, cooling towers and other equipment affected by heat so as to take advantage of shade and natural cooling, e.g., the wind normally should flow across the packing in a cooling tower
allow for growth in the facility — size the utilities, i.e., electricity, compressed air, steam, heating and ventilation, purge gas, fuel and even sewers and rail spurs, for future expansions.
After the first pass through the design, review the layout with operations and maintenance, together, in the same room. If you regularly use contractors such as riggers and crane companies, ask them to check the drawings for lifting requirements and scaffolding, removal and replacement of major equipment.
Several common mistakes often haunt plant designers. Foremost are those related to pipe racks. Too often, delicate instrument cables are run close above steam piping, parallel to power lines and in places where they are unshielded from the sun. Then, there’re plant expansions. A premium on downtime means that new wires seldom are added to old conduit. This means new wires and new conduit. Good sense dictates filling conduit to a maximum and allowing for future removal and replacement of rotting conduit, terminal strips and pipe. Plan for future tie-ins; one plant had a single shutoff valve in the steam system.
I’ve been burned more than once by designs that are blind to insulation needs. Design engineers ordering tanks frequently forget to allow for insulation lagging of flanges, manways and instruments — sometimes because these requirements aren’t known when the tank was ordered. However, lack of insulation can pose real risks unless the company enforces a safety standard on surface temperature. Operators have been burned to death attempting to squeeze between uninsulated pipe.
Another mistake is not considering the rigging of equipment for installation, now and in the future. Plan for trolleys and anchor points in the layout. I remember one project where lugs hadn’t been installed on some spools of a large ceramic-lined pipe. This oversight helped turn a four-day outage into one lasting 10 days. Another example: a tank to be welded to a structure came with legs.
The goal is to design a layout that improves the operability, safety and production capability of the plant. This requires an understanding of the needs of mechanics, riggers and operators.
taken from http://www.chemicalprocessing.com/articles/2008/068.html
Wednesday, August 27, 2008
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