Silicon photonic crystal has holes of the right sizes and waveguides
In computer simulations, the researchers have demonstrated an approximate cloaking effect created by concentric rings of silicon photonic crystals. The mathematical proof brings scientists a step closer to a practical solution for optical cloaking.
"This is much more than a theoretical exercise," said Harley Johnson, a Cannon Faculty Scholar and professor of mechanical science and engineering at Illinois. "An optical cloaking device is almost within reach."
Axisymmetric photonic crystal structures may be designed to possess interesting optical properties, particularly when the photonic band structure of the material is highly anisotropic. We use finite element calculations to demonstrate an approximate electromagnetic cloaking effect imparted by a structure consisting of concentric silicon photonic crystal layers. The results show that it is possible to bend light around an object by simply using anisotropy. The calculations show that the cloaking mechanism is fundamentally different from Pendry's approach. This design may work as a practical solution for optical cloaking.
D. Xiao and H. T. Johnson, “Approximate cloaking effect in an axisymmetric silicon photonic crystal structure,”
Optics Letters, 33,
860-862 (2008).
In October 2006, an invisibility cloak operating in the microwave region of the electromagnetic spectrum was reported by researchers at Duke University, Imperial College in London, and Sensor Metrix in San Diego. In their experimental demonstration, microwave cloaking was achieved through a thin coating containing an array of tiny metallic structures called ring resonators.
To perform the same feat at much smaller wavelengths in the visible portion of the spectrum, however, would require ring resonators smaller than can be made with current technology, Johnson said. In addition, because metallic particles would absorb some of the incident light, the cloaking effect would be incomplete. Faintly outlined in the shape of the container, some of the background objects would appear dimmer than the rest.
To avoid these problems, postdoctoral research associate Dong Xiao came up with the idea of using a coating of concentric rings of silicon photonic crystals. The width and spacing of the rings can be tailored for specific wavelengths of light.
"When light of the correct wavelength strikes the coating, the light bends around the container and continues on its way, like water flowing around a rock," Xiao said. "An observer sees what is behind the container, as though it isn't there. Both the container and its contents are invisible."
Currently simulated in two dimensions, the cloaking concept could be extended to three dimensions, Xiao said, by replacing the concentric rings with spherical shells of silicon, separated by air or some other dielectric.
The researchers' optical cloaking technique is not perfect, however. "The wave fronts are slightly perturbed as they pass around the container," said Johnson, who also is affiliated with the university's Beckman Institute and the Frederick Seitz Materials Research Laboratory. "Because the wave fronts don't match exactly, we refer to the technique as 'approximate' cloaking."
FURTHER READING
Invisibility to sound for acoustic shields (hide nuclear deterrent submarines from sonar detection) and shaping sound and other waves (like earthquakes) is also coming soon
Researchers at the University of Illinois are the first to achieve optical waveguiding of near-infrared light through features embedded in self-assembled, three-dimensional photonic crystals. Applications for the optically active crystals include low-loss waveguides, low-threshold lasers and on-chip optical circuitry.
Harley Johnson site
Photonic crystal tutorial
Silicon photonic crystal
Scanning electron micrograph of a porous silicon photonic crystal
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Sound shield: An acoustic cloak comprising alternating layers of sound-scattering materials should make objects invisible to sonar--and insulated from sound. In this computer-generated image, a cylinder (green circle) is coated with 200 layers of such a material, which was found to be the optimal design. Sound waves moving from left to right (their peaks and troughs are represented by red and blue lines) flow past the object and reform on the other side with no distortion.
Credit: New Journal of Physics
From Technology Review: Engineers have designed a material that redirects sounds and could be used in buildings to shield them from noises. The sound-shielding material, which, if actually made, would be the first acoustic cloaking device, could also be useful in hiding military ships and other vessels from sonar. Engineers led by José Sánchez-Dehesa at the Polytechnic University of Valencia, in Spain, have created a plan for making an acoustic shield, using alternating layers of two different materials. These materials would comprise arrays of sonic crystals--patterns of small rods made of aluminum or other materials that allow some sound waves to pass while blocking the passage of others. This is follow up work related to metamaterials that are being developed for superlenses and optical invisibility.
Sánchez-Dehesa has modeled a two-dimensional acoustic cloak but says that extrapolating his work to three dimensions should be straightforward. "We're proposing a cloak for any shape," he says. Hiding warships from sonar is one possible application. But Sánchez-Dehesa is interested in the problem of noise generally. "In principle," he says, "it's possible to make this cloak very thin," on the order of centimeters. "If we're able to design a wall to put in a house to screen external noise, it would be very nice." Cummer imagines columns for concert halls that do structural work but, acoustically, are effectively not there.
Unlike light cloaks, which can shield objects from light of only one frequency, acoustic cloaks should be able to shield an object to a broad range of frequencies. The speed of sound, however, is not a universal constant, so it should be possible to craft broadband acoustic cloaks. [Speculation: Similar principles could work for shielding against earthquake waves through the ground]
Acoustic cloaking in two dimensions: a feasible approach
This work proposes an acoustic structure feasible to engineer that accomplishes the requirements of acoustic cloaking design recently introduced by Cummer and Schurig (2007 New J. Phys. 9 45). The structure, which consists of a multilayered composite made of two types of isotropic acoustic metamaterials, exactly matches the conditions for the acoustic cloaking. It is also shown that the isotropic metamaterials needed can be made of sonic crystals containing two types of material cylinders, whose elastic parameters should be properly chosen in order to satisfy (in the homogenization limit) the acoustic properties under request. In contrast to
electromagnetic cloaking, the structure here proposed verifies the acoustic cloaking in a wide range of wavelengths; its performance is guaranteed for any wavelength above a certain cutoff defined by the homogenization limit of the sonic crystal employed in its fabrication.
They present an acoustic cloak that could be physically realizable. In brief, the proposed cloak is based on a multilayered structure consisting of two layers with the same thickness and made up of two different acoustic isotropic metamaterials. These metamaterials are built with sonic crystals (i.e. periodic arrays of sonic scatterers) based on two types of elastic cylinders that have to accomplish certain requirements on their mass density and effective sound speed. Numerical experiments based on multiple scattering method are presented to support the exact performance of the proposed cloak.
The paper is organized as follows. First, in section 2, we review the solution in the previous paper and report our approach to get the acoustic cloaking. Numerical experiments demonstrating the performance and properties of the proposed cloak are also presented and discussed. Section 3 describes the recipe to build the metamaterials needed to fabricate the multilayered cloak making it physically feasible. Finally, the work is summarized in section 4.
FURTHER READING
Jose Sanchez-Dehesa is one of the researchers that developed the new acoustic cloak design
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The Defense Science Board will examine how the Defense Department could benefit from scientific breakthroughs in the field of synthetic biology.
John Young, the under secretary of defense for acquisition, technology and logistics, wants DSB members to “survey” developments in biotechnology and “attempt to project transition paths from research into current and future defense applications,” according to a June 11 memo Young sent to the panel’s chairman.
The United Kingdom's Biotechnology and Biological Sciences Research Council's released a report 'Synthetic Biology: social and ethical challenges' on June 9 2008
There is no agreed definition of synthetic biology, but it is best understood as the deliberate design of biological systems and living organisms using engineering principles.
The technological manipulation of life was first advocated at the turn of the last century and was instrumental in shaping the rise of molecular biology. However, the widespread use of the term has only occurred since the mid-2000s, as the field has emerged owing to the falling cost of gene sequencing and synthesis. The aims of synthetic biology include: 1) the production of minimal living genomes; 2) the design of interchangeable parts that can be assembled into pathways for the fabrication of novel components; 3) the construction of entirely artificial cells; and 4) the creation of synthetic biomolecules.
RELATED READING
John Young was a witness on the 21 March 2007 hearing to receive testimony on Department of Defense counterproliferation, counterterrorism, and science and technology priorities
John Young receiving Presidential Citation at Georgia Tech on May 24, 2008
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Research and development work on adapting the design of the Ford (CVN-78) class aircraft carrier nuclear power plant for use in a new Navy cruisers CG(X) and could be extended to amphibious assault vessels.
Congress in 2007 passed the National Defense Authorization Act for 2008, an annual piece of legislation that tells the Pentagon how it should spend its budget. Under the act all future aircraft carriers, submarines and battle cruisers have to be built with a nuclear power system at their heart.
The National Defense Authorization Bill for 2009, which the Senate has still to pass, aims to shift the process up a gear by adding various types of amphibious assault ships to the list of those that must be powered by nuclear reactors in the future. Amphibious ships come in various forms, from those that incorporate a dock for landing craft, to undersized aircraft carriers for helicopters and vertical take-off aircraft - or a mixture of both. The vessels' position in combat can also vary - from a "stand-off" over-the-horizon location to being moored to a pier in a combat zone.
Equipping such ships with nuclear reactors would have another advantage in military operations, says Wright. "Assault ships are carrier escort vehicles and will no longer be holding up a carrier task force's progress by having to be refuelled every three to five days," she says.
There was a 2007 study on the use of more nuclear power in the United States Navy
A potential advantage of nuclear power postulated by some observers is
that a nuclear-powered ship can use its reactor to provide electrical power for use
ashore for extended periods of time, particularly to help localities that are
experiencing brownouts during peak use periods or whose access to electrical power
from the grid has been disrupted by a significant natural disaster or terrorist attack. The Navy has stated that the CG(X) is to have a total power-generating capacity of about 80 megawatts (MW). Some portion of that would be needed to operate the reactor plant itself and other essential equipment aboard the ship. Much of the rest might be available for transfer off the ship. For purposes of comparison, a typical U.S. commercial power plant might have a capacity of 300 MW to 1000 MW. A
single megawatt can be enough to meet the needs of several hundred U.S. homes,
depending on the region of the country and other factors.
The Navy is looking to install radar requiring 30 or 31 megawatts of power onto its new Cruiser.
A nuclear-powered CG(X) could cost roughly 32% to 37% more than a conventionally powered CG(X). The Navy estimates that building the CG(X) or other future Navy surface ships with nuclear power could reduce the production cost of nuclear-propulsion components for submarines and aircraft carriers by 5% to 9%, depending on the number of nuclear-powered surface ships that are built.20 Building one nuclear-powered cruiser every two years, the Navy has testified, might reduce nuclear-propulsion component costs by about 7%.
At a crude oil cost of $74.15 per barrel (which was a market price at certain points in 2006), the life-cycle cost premium of nuclear power is:
— 17% to 37% for a small surface combatant;
— 0% to 10% for a medium sized surface combatant; and
— 7% to 8% for an amphibious ship.
Newly calculated life-cycle cost break-even cost-ranges, which supercede the break-even cost figures from the 2005 NR quick look analysis, are as follows:
— $210 per barrel to $670 per barrel for a small surface combatant;
— $70 per barrel to $225 per barrel for a medium-size surface combatant; and
— $210 per barrel to $290 per barrel for an amphibious ship. In each case, the lower dollar figure is for a high ship operating tempo, and the higher dollar figure is
for a low ship operating tempo.
A 2006 Navy study states that for a medium-size surface combatant that is larger than the DDG-1000, an additional cost of about $600 million to $700 million would equate to a procurement cost increase of about 22%. If building a Navy surface combatant or amphibious ship with nuclear power rather than conventional power would add roughly $600 million to $700 million to its procurement cost., then procuring one or two nuclear-powered CG(X)s per year, as called for in the Navy’s 30-year shipbuilding plan, would cost roughly $600 million to $1,400 million more per year than procuring one or two conventionally powered CG(X)s per year, and procuring a force of 19 nuclear-powered CG(X)s would cost roughly $11.4 billion to $13.3 billion more than procuring a force of 19 conventionally powered CG(X)s. For purposes of comparison,the Navy has requested a total of $13.7 billion for the SCN account for FY2008.
UPDATE: The United States navy has 280 active ships The Aircraft carriers (12 current, 2 under construction, 2 planned) and submarines (70 now, 5 under construction or ordered, at least 9 more planned) in the US navy are nuclear powered already.
The US has 10 amphibious assault ships (helicopter carriers) and 11-18 amphibious transport docks.
Amphibious assault ships (small aircraft carriers for marines)
* Tarawa class (3 in commission, 2 decommissioned)
* Wasp class (7 in commission, 1 under construction)
Amphibious transport docks (200 meters long versus 173 meters for a cruiser)
* Austin class (9 in commission, 2 decommissioned, 1 converted to an auxiliary command ship)
* San Antonio class (2 in commission, 3 under construction, 4 more planned)
The US Navy has 22 cruisers and 52 destroyers with 3 under construction, 7 more planned.
Dock Landing ships
* Whidbey Island class (8 in commission)
* Harpers Ferry class (4 in commission)
So 32-50 ships in the amphibious and cruiser categories could become nuclear powered at about 2 at a time over 16-25 years from 2015-2040.
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As Mr Miyagi said in Karate Kid.. If do right, no can defence
The U.S. Navy can't stop China's most sophisticated anti-ship missile (purchased from Russia) -- and won't even start testing a defense until 2014. I don't think it is an issue between China and the USA because I do not believe they will be fighting. More relevant is if Iran gets the missile. Then it would be important for the USA to use spies, satellites and other means to find any missiles and destroy them before putting the navy within range. If Iran got it then it would change the tactics in any Iran/USA war. A war over Taiwan is not in the offing as the Taiwan presidential and legislative election has placed pro-Chinese politicians in Taiwan. They are going to moving to a common market. If Taiwan and China move to a European Union type situation then there will not be war.
UPDATE:
It was pointed out to me that the US tactics would not be that greatly effected.
1) Pound them using air force. Air craft carriers are used because US does not have enough landbased friends. B52's do most of the damage. Navy is for precision attacks. In the Iran case, airforce from Iraq, Afganistan, Dubai, and Suadi would mash them into stone age.
2) Drive army in from a friend. In this case, Iraq and Afganistan. [if wanting a land assault which the US probably does not except for some kind of smash and dash]
3) Navy would sit well offshore and cheer them on.
However, the US military pumping up its enemies would get the Admirals desired project or pet weapon system funded.
The Sizzler starts at subsonic speeds. Within 10 nautical miles of its target, a rocket-propelled warhead separates and accelerates to three times the speed of sound, flying no more than 10 meters (33 feet) above sea level. On final approach, the missile 'has the potential to perform very high defensive maneuvers,' including sharp-angled dodges, the Office of Naval Intelligence said in a manual on worldwide maritime threats.
The U.S. Navy, after nearly six years of warnings from Pentagon testers, still lacks a plan for defending aircraft carriers against a supersonic Russian-built missile, according to current and former officials and Defense Department documents.
Air power australia has photos of the Sizzler supersonic missileHat tip to Wired defense blog
The missile, known in the West as the ``Sizzler,'' has been deployed by China and may be purchased by Iran.
The Defense Department's weapons-testing office judges the threat so serious that its director, Charles McQueary, warned the Pentagon's chief weapons-buyer in a memo that he would move to stall production of multibillion-dollar ship and missile programs until the issue was addressed.
``This is a carrier-destroying weapon,'' said Orville Hanson, who evaluated weapons systems for 38 years with the Navy. ``That's its purpose.''
FURTHER READING
China's off the shelf air defense
Sino defence forum discusses the Sizzler missile and the Sunburn (supersonic all the time)
The Sizzler is smaller in size and lighter. I think the main difference is that the sunburn travels at supersonic speeds all the time, therefore requiering a big load of fuel, wich in turn makes the missile big and heavy. The Sizzler cruises at subsonic speeds and goes supersonic in terminal phase. But there are different versions of the "Club" some are "conventional" subsonic CMs over the entire flight. The Sizzlers range is longer than the Sunburn's.
And I think the Sizzlers also have the capability of interoperability. Meaning they can exchange info. One "lead" missiles flies at high altitude searching for targets with it's radar, while the other missiles of a barrage stay low and recieve info from the lead-missile.
Sino Defence has info on the missile
For political reasons, China may get small indigenous air craft carriers around 2013 (not nuclear powered, competitive with non-USA aircraft carriers other than the expected future French aircraft carrier
Here is a more complete list of arsenal of China's navy.
3M-54E (SS-N-27) Anti-Ship Cruise Missile
Sunburn 3M-80E (SS-N-22) Ship-to-ship Missile
The purchase of the 3M-54E1 with 300 kilometer (180 mile) range back in 2005
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A full-scale, fully cantilevered electromagnetic railgun developed by the Defense Advanced Research Projects Agency (DARPA) has successfully launched a full-sized projectile, with size and weight similar to a 120mm mortar, at speeds of 430 meters-per-second. 430 meters/second would be a little faster than the 101-318 meter/second speed of regular mortar firings.
The railgun is the largest caliber supersonic railgun in the world and the first-ever successful fullscale cantilevered railgun to shoot a mortar-size projectiles.
The railgun is 2.4 meters long and weighs 950 kilograms. It is fully cantilevered from the breech end without visible droop. A cantilevered design is important because fieldable gun designs will need the ability to change aiming on a shot-to-shot basis. Built-in muzzle shunts quickly extinguish muzzle arc and reduce muzzle flash by providing an alternate current path.
The system has been demonstrated with reduced-mass projectiles to velocities around 550 meters-per-second and full-mass projectiles weighing 16.6 kilograms to 430 meters-per second. More than 30 projectile launches have been conducted during this program, which began in 2005. Testing of the full-scale railgun began in mid-2007.
This DARPA-sponsored project has been conducted by researchers from the Institute for Advanced Technology at the University of Texas at Austin. The ultimate goal is to be able to launch a slightly modified M934 mortar projectile jointly developed with the U.S. Army’s Armament, Research and Development and Engineering Center. Test launches of the M934 mortar projectile are scheduled for April to June 2008.
A regular M934 mortar
FURTHER READING
Using railguns for space launch.
Previous coverage of other railgun tests
Magnetic catapult better for space launches.
Part of the militaries vision of railguns and other future military systems [15 page pdf]
ElectroMagnetic (EM) Gun Technology Maturation & Demonstration
The ElectroMagnetic (EM) Gun Technology Maturation & Demonstration ATO focuses on developing and demonstrating key EM gun subsystems at or near full-scale to support future armament system developments. Future armored combat systems require more lethal yet compact main armament systems capable of defeating threat armor providing protection levels greatly in excess of current systems. The goal is to reduce technical risk associated with EM Gun technology by demonstrating meaningful technical progress at subsystem level; gain an understanding of EM technology issues; identify technology trends; conduct return on investment analyses; and craft a technology development strategy. By FY08, this effort will build a lightweight cantilevered high-fidelity railgun with integrated breech and muzzle shunt and demonstrate performance at hypervelocity and multi-round launch capability. It will integrate compact, twin counter-rotating pulsed alternator power supplies, conduct subsystem functional tests, and accomplish high fidelity PPS demonstrations that will establish requisite performance criteria to transition into the follow-on ATD. EM armaments offer the potential to field a leap-ahead capability by providing adjustable velocities, including hypervelocity, greatly above the ability of the conventional cannon. EM armaments could greatly reduce the sustainment requirements and vulnerabilities of conventional cannon systems and potentially can be fully integrated with electric propulsion and electromagnetic armor systems to provide an efficient, highly mobile, and deployable armored force. If successful, the payoff of EM gun technology will be increased lethality and lethality growth potential and enhanced platform survivability by reducing launch signature, and carrying less explosive energy on board.
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The source of this post is this 10 page IEEE paper, Launch to Space With an Electromagnetic Railgun by
Ian R. McNab, Senior Member, IEEE The cost of electricity for a launch will be negligible, as shown below. Barrel life is central to the successful economics for this system. A system might cost $1.3 billion and launch for $500/kg. Recent tests fired 7 pound projectiles at 5637 mph. Lunar escape velocity is 5,324 mph. So the truck sized system is already good enough to launch from the surface of the moon. Classic science fiction "the Moon is Harsh Mistress" by Heinlein could become reality.
Other gun launch systems were reviewed and found lacking:
Only Electromagnetic railguns seem worthy of further study for this application.
This choice was made on the basis that:
• they have already achieved 7 km/s at small scale, and 10.6 MJ at 2–3 km/s (with a test system able to go to 32 MJ) ;
• significant development is being funded for military applications;
• they offer the possibility of achieving the muzzle velocities and energies required;
• the potential cost savings seem significant based on our estimates.
Methods of accelerating large masses in large bore railguns will need to be developed, and some concepts are suggested here.
The muzzle velocity in the range needed for a moon-based launch system have already been achieved in the recent test firings. (about 2.5 km/s). Then it would just be a matter of scaling up energy linearly for heavier masses. (E=MC**2). The 10.6MJ system shot a 7 pound shot. The current 32MJ could fire 21 pounds (10kg) at the desired speed. A 320MJ system could fire 100kg payloads. Using resources available on the moon, this could serve as the forward base for sending material to Mars in support of a manned mission or to supply orbital infrastructure around the earth.
Even a scaled model would have substantial energy requirements: 10 kg at 7 km/s is a muzzle energy of 250 MJ, and with a launcher efficiency of 80%, an energy input 300 MJ would be required. This is comparable to the energy obtained from capacitor modules for the U.S. National Ignition Facility for laser fusion research.
The estimated system cost of $1.3B and a component life of 10 000 launches without replacement yields a cost of about $530/kg into orbit. It is important to note that this does not include the cost of the vehicle itself or operational costs on the Earth or in space, and these items need to be estimated.
The UTSTAR railgun tube.
Railgun launcher parts and sizes for the IEEE designed system
A chart with speed, energy and other variable tradeoffs.
Basically below 7km/s the total energy needed to launch a commercially viable amount of annual payload increases rapidly
The extension of this technology to the muzzle velocities ( 7500m/s) and energies ( 10 GJ) needed for the direct launch of payloads into orbit is very challenging, but may not be impossible. For launch to orbit, even long launchers ( 1000 m) would need to operate at accelerations 1000 gees to reach the required velocities, so that it would only be possible to launch rugged payloads, such as fuel, water, and material. Estimated launch costs could be attractively low ( $600/kg) compared with the Space Shuttle ( $20 000/kg), provided that acceptable launch rates can be achieved.
So triple the muzzle speed and increase power by 1000 times the current test level or 330 times the current 32 MJ system.
A disadvantage of gun launch is that the launch package has toleave the gun barrel at a very high velocity ( 7500 m/s) through the Earth's atmosphere, leading to a very high aerothermal load on the projectile.
However, the current 32 MJ system is only about the size of a truck. So a nice big scramjet that could fly at Mach 10-12 could use a moderately scaled up version of the rail gun current system to fly above most of the atmosphere and then fire hardened payloads into orbit. Then less heat shielding would be needed.
To provide 500 tons/year to orbit would require 2000 launches/year—a little over five per day on average.
The launch package is cargo within a shaped shell with a small rocket.
The source of this post is this 10 page IEEE paper, Launch to Space With an Electromagnetic Railgun by
Ian R. McNab, Senior Member, IEEE
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Photograph taken from a high-speed video camera during a record-setting firing of a seven-pound bullet fired from a truck-sized electromagnetic railgun at seven times the speed of sound and sent a visible shockwave through the air before crashing into a metal bunker filled with sand.
UPDATE: New article written on using railguns for space launch. This system already would be able to launch projectiles with enough speed for lunar based space launches.
Hypersonic vehicles could carry railguns as weapons or too launch into space above most of the atmosphere with smaller railgun systems that use less shielding for the projectiles. The MHD version of a hypersonic plane would be ideally suited for powering railgun and laser weapons.
Hat tip to reader Scott: the U.S. Navy has demonstrated World's Most Powerful Electromagnetic rail gun (EMRG) at 10.64 Megajoules
An electromagnetic catapult, or railgun, is on track for deployment on U.S. warships around 2012, according to the Office of Naval Research (ONR).
The Navy's latest test made history with the world's fastest muzzle velocity of 5,637 miles per hour--generating a record 10.6 megajoules of energy (1 joule = 1 watt-second).
If the Navy decides to deploy the railgun, it plans to have a final design in place for approval by 2012. Initial prototypes will probably shoot a single projectile, but plans for rapid-fire versions are already on the drawing board.
The final design specification calls for a muzzle velocity of 5,760 mph for a weapon that is capable of launching a projectile in a parabolic ballistic path 94 miles high. It must strike targets within six minutes at 3,840 mph.
Initial tests showed that targets can be obliterated by the kinetic force of the impact with pinpoint accuracy without shrapnel, which is the most common cause of collateral damage when using high-explosive munitions.
At full capability, the rail gun will be able to fire a a 40-pound projectile more than 200 nautical miles at a muzzle velocity of mach seven and impacting its target at mach five. In contrast, the current Navy gun, MK 45 five-inch gun, has a range of nearly 13 miles. The high velocity projectile will destroy its targets due to its kinetic energy rather than with conventional explosives.
The safety aspect of the rail gun is one of its greatest potential advantages, according to Dr. Elizabeth D'Andrea, ONR's Electromagnetic Railgun Program Manager. Safety on board ship is increased because no explosives are required to fire the projectile and no explosive rounds are stored in the ship's magazine.
Science and technology challenges met by ONR in the development of the rail gun include development of the launcher, pulse power generation and the guided projectile design. The program's goal is to demonstrate a full capability, integrated railgun prototype by 2016-2018.
MIT Technology Review also covers the rail gun
FURTHER READING
Nov, 2007, I had reported on a 32 megajoule rail gun delivered for testing.
BAE Systems has delivered a functional, 32-megajoule Electro-Magnetic Laboratory Rail Gun (32-MJ LRG) to the U.S. Naval Surface Warfare Center in Dahlgren, Va. Installation of the laboratory launcher is currently underway, and according to BAE, this is the first step toward the Navy’s goal of developing a tactical 64-megajoule ship-mounted weapon.
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University of Pennsylvania engineers and physicians have developed a carbon nanopipette thousands of times thinner than a human hair that measures electric current and delivers fluids into cells. Researchers developed this tiny carbon-based tool to probe cells with minimal intrusion and inject fluids without damaging or inhibiting cell growth. Drexel University College of Engineering had previously developed carbon nanotube pipettes in 2007. This work is another step to realizing one aspect of the vision of nanomedicine.
Researchers believe the pipettes will be useful for concurrently measuring electrical signals of cells during fluid injection. In addition, the pipettes are transparent to X rays and electrons, making them useful when imaging even at the molecular level. Adding a functionalized protein to the pipette creates a nanoscale biosensor that can detect the presence of proteins.
“Penn’s Micro-Nano Fluidics Laboratory now mass-produces these pipettes and uses them to inject reagents into cells without damaging the cells,” Bau said. "We are ultimately interested in developing nanosurgery tools to monitor cellular processes and control or alter cellular functions. We feel CNPs will help scientists gain a better understanding of how a cell functions and help develop new drugs and therapeutics."
Just as important as the mechanical properties of carbon nanopipettes, however, is the ease of fabrication, said Michael Schrlau, a doctoral candidate and first author of the study, “Carbon Nanopipettes for Cell Probes and Intracellular Injection,” published in the most recent issue of Nanotechnology. “After depositing a carbon film inside quartz micropipettes, we wet-etch away the quartz tip to expose a carbon nanopipe. We can simultaneously produce hundreds of these integrated nanoscale devices without any complex assembly,” he said.
The next challenge for researchers is fully utilizing the new tools in nanosurgery.
"We will need to go beyond the proof-of-concept, development stage into the utilization stage," Schrlau said. "This includes finding the appropriate collaborations across engineering, life science and medical disciplines."
FURTHER READING
Drexel University College of Engineering researchers had successfully developed carbon nanotube-tipped pipettes in April 2007. the pipettes could become key to cell biology in-situ DNA sequencing and organelle-targeted drug delivery. This development makes it possible to perform injections or probe the fluid, not just inside a cell, but in specific regions inside the cell, maybe even specific organelles.
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Pulse detonation engines (PDE) can achieve a maximum of 50% efficiency verus 30% for conventional jet engines Pratt & Whitney and General Electric now have active PDE research programs in an attempt to commercialize the designs with high pulse rates of 50-100 times per second to allow for less vibration. Some of the top scientists and engineers in the field say that with the right economic incentives and a few well-placed technology leaps, they could get to a flight-ready system in five years. (Air and Space magazine sept 2007). They are 3 to 4 on the technology readiness scale (working in the lab).
Pulse-detonation engines could push aviation into a new age, leading to superefficient subsonic jetliners, cheaper suborbital flight and more affordable space access.
There is a lengthy article at Air and Space Magazine on pulse detonation
The pace of current research and development points the way to three phases of pulse detonation engine technology, each a bit more complex than the one preceding it.
The first phase could be called the “pure PDE”: Essentially it focuses on developing the detonation tube, which would power a very-high-speed, air-breathing missile. In this application, engineers and scientists can punt on two of the biggest technology problems—life, or the durability of the system, and noise. The missile has to fly only once, so long life for the metals or components is not a concern. And at the high speeds—around Mach 6—and altitudes in which the missile would operate, less noise is also moot. This is the area in which Adroit Systems, and later Pratt & Whitney, made the most strides. It was their machine that would have been flown on NASA’s F-15B.
The next phase could involve using pulse detonation engines to address another pressing issue in combustion: afterburners for fighter aircraft. Today’s fighter engines simply spray aerosolized fuel into a long tube aft of the turbine section, literally dumping extra fuel-air mixture into the hot gas stream for a brief extra kick of speed. Engineers think that if they add pulse detonation technology to a low-bypass-ratio turbine engine—the modern fighter jet engine—they can get the efficiency benefit of pressurized, shockwave combustion. It’s relatively simple because the pulse detonation tube would be at the end of the engine and not in the middle of the turbo-machinery. Here again, life and noise are less of an issue than they might be in a commercial aircraft. Fighter pilots only fly on afterburner about five percent of the time, and anyone who has seen an airshow knows fighter jocks usually don’t worry about making a racket.
The third phase is where it gets most complicated, but is the one that may offer the biggest payoff: pulse detonation in the middle of the engine. Having a compressor upstream and a turbine downstream, says GE’s Dean, is a potential high-value payoff that keeps his company attracted to PDE development. A PDE-based combustor is one of the main areas of work for a young researcher on Dean’s team named Adam Rasheed. Rasheed is chronicling his work on a publicly available blog, “From Edison’s Desk” (www.grcblog.com). The publicity seems to have done him some good: The Massachusetts Institute of Technology’s Technology Review magazine in 2005 named Rasheed one of under the age of 35.
Like everyone else, Rasheed has his eyes on a jet engine that burns five percent less fuel—an enormous leap compared with today’s fuel-saving techniques. In a world in which efficiency improvements of even 0.2 percent are considered a major breakthrough, “PDEs represent a possible game-changing technology that could revolutionize aerospace propulsion,” Rasheed writes. Even a one percent improvement would save hundreds of millions of dollars in fuel.the world’s top 35 researchers
FURTHER READING
29 page overview of pulse detonation engine technology written in 2004Nuclear pulse rocket engines, which can go up to 10% of lightspeed primarily using technology that we have had for decades.
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The Center for Responsible Nanotechnology has an interesting article on some trends towards lower cost for weapon system development and faster weapon system development cycles. One aspect of the article is whether the "decide to kill" option should be left to armed robotic systems. I do not think that is as big an issue for a few reasons.
The decide function is already passed along from people to weapons in the form of mines and deadly traps. To a shorter timeframe in the form of gravity bombs and bullets after they are released.
The decide function would be less of an issue if the robot was using incapacitation style weapons. Tranquilizers, tasers etc...
Less lethal weapons are being actively studiedm, developed and deployed.
Robotic systems would have the option of being more selective and ethical than carpet bombing and minefields.
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BAE Systems has delivered a functional, 32-megajoule Electro-Magnetic Laboratory Rail Gun (32-MJ LRG) to the U.S. Naval Surface Warfare Center in Dahlgren, Va. Installation of the laboratory launcher is currently underway, and according to BAE, this is the first step toward the Navy’s goal of developing a tactical 64-megajoule ship-mounted weapon.
Eight and 9-megajoule rail guns have been fired before, but providing 3 million amps of power per shot has been a limitation. At 32 megajoules, this new system appears to be the most powerful rail gun ever built, and the Office of Naval Research is installing additional capacitors at the Dahlgren facility to support it. The planned 64-megajoule weapon, if it’s ever built, could require even more power—a staggering 6 million amps.
The Navy’s electrically-propelled DDG 100 Destroyer, Chaboki says, is a prime candidate for the final 64-megajoule system. Around 72 megawatts (MW) of the vessel’s power can be used for propulsion. But during combat, the destroyer’s speed could be brought down, freeing up energy for a rail gun. Chaboki calculates that firing the 64-megajoule weapon six times per minute would require 16 MW of power, which would be supplied by either onboard capacitors or pulsed alternators.
Effective rail guns will require a major breakthrough in materials between now and 2020, to keep the guns themselves from being shredded by each high-velocity barrage.
There was a 2003 analysis of using railguns for orbital launches. For launch to orbit, even long launchers (>1000 m) would need to operate at accelerations >1000 gees to reach the required velocities, so that it would only be possible to launch rugged payloads, such as fuel, water, and material. A railgun system concept is described here and technology development issues are identified. Estimated launch costs could be attractively low (<$600/kg) compared with the Space Shuttle (>$20 000/kg), provided that acceptable launch rates can be achieved.
A european space agency study of rail guns for space launches
A system to launch single stage rocket propelled projectiles to put in orbit nano-satellites using a 3.4 GJ railgun with a length of 180 m.
RELATED READING
Ram accelerators would be cheaper and quicker to develop for gun launching payloads into space.Superthread carbon nanotubes would be the kind of material needed to help reinforce the rail gunThere is other progress being made on better materials including nanograin metals.
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I had written in 2006 about the Military Nanotechnology book by Altmann
The Center for Responsible Nanotechnology has reviewed the book.
Some consideration should be given to
1. What are the non-nanotech ways that production could greatly increase ?
Breakthroughs that allow expanded reel to reel production. ECD Ovonics quantum control devices made from polymers able to produced without or with limited performance degradation relative to silicon. Allowing for MEMS and computers to be produced far more quickly. MEMS can be used to create UAVs.
Breakthroughs with arrays of MEMS/NEMS to speed up 3D printing from the nanoscale up.
Mere force multiplier effects or the enabling of a more antiseptic war does not really alter the geopolitical situation. Especially if the US and China are near the lead in new production increases.
Also, there is no motivation for global governance if it is primarily the existing major powers that get more production and maintain a lead and dominance over others.
I think the existing national powers and the existing political structure could adapt to the most common and likely scenarios without ceding sovereignty.
2. How important is production relative to strategy and tactics or radically new systems capabilities ?
More clever usage of relatively mundane conventional weapons and non-weapons technology could be used to far greater effect. Air superiority and ruthlessness (similar to the Romans over Carthage or using the WW2 russian tactics of scorched earth but on enemy terrain) could be used to genocide a country in weeks.
Merely the production of a lot more robotic weapons does not overcome nuclear deterrent.
Look there is a swarm of UAV's crossing the Ocean... launch ... launch.
How is that different from look there are ICBMs launching and crossing the Ocean..launch...launch?
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China's taken six years to achieve 40 percent of a 20-year target of quadrupling per-capita GDP by 2020 with an increase to 16,084 yuan this year (2007).
The yuan rose to as much as 7.4834 versus the dollar from 7.4926 yesterday, heading for the biggest weekly gain in five weeks. It has climbed more than 10 percent versus the U.S. currency since the end of a fixed exchange rate in July 2005 and fallen 7 percent against the euro.
There's debate in China on the merits of a stronger currency, which would ease trade tensions and the inflow of cash by making exports more expensive. A report circulated last week within the National Development and Reform Commission, the top planning agency, called for a 15 percent to 20 percent one-off revaluation
China's economy, the biggest contributor to global growth, grew 11.5 percent in the third quarter, adding pressure for faster currency appreciation and higher borrowing costs to curb inflation and asset bubbles.
I have predicted that China's will pass the USAs economy on an exchange rated basis in 2018 plus or minus 3 years.
My prior article with an earlier prediction of 2020 for China's economy passing the USAs
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