20 most recent innovations in physics

The drip-free wine bottle!

Mon, 27 Mar 2017 00:00:00 Z

Anyone who has ever poured wine knows about the drips that fall off the side of the bottle. At long last, a Brandeis physicist has figured out a fix.

Drips are the bane of every wine drinker's existence. He or she uncorks a bottle of wine, tips it toward the glass, and a drop, or even a stream, runs down the side of the bottle. Sure, you could do what sommeliers in restaurants do, wrapping a napkin around the neck of the bottle to catch the liquid, but who has time for that? Much more likely, you’ll ruin the tablecloth.

Daniel Perlman — wine-lover, inventor and Brandeis University biophysicist — has figured out a solution to this age-old oenophile's problem. Over the course of three years, he has been studying the flow of liquid across the wine bottle's lip. By cutting a groove just below the lip, he's created a drip-free wine bottle.

Flying Jellyfish-Like Machine

Mon, 02 Dec 2013 00:00:00 Z

Many approaches to building small aerial robots try to mimic the flight of insects such as fruit flies. The challenge in that, explained Leif Ristroph of New York University, is that the flapping wing of a fly is inherently unstable. To stay in flight and to maneuver, a fly must constantly monitor its environment to sense every gust of wind or approaching predator, adjusting its flying motion to respond within fractions of a second. To recreate that sort of complex control in a mechanical device – and to squeeze it into a small robotic frame – is extremely difficult, Ristroph said.

After some tinkering, he devised a new way of flapping-wing flight that doesn't need any sort of control or feedback system to be stable, and is akin to the swimming motions of jellyfish. The prototype device, weighing just two grams and spanning eight centimeters in width, flies by flapping four wings that are arranged like petals on a flower. While the up-and-down motion of the wings resembles a pulsating jelly,, the device's ultimate fluttering flight may be more similar to that of a moth. The vehicle can hover, ascend, and fly in a particular direction.

New coating turns ordinary glass into super-slippery glass

Thu, 08 Aug 2013 00:00:00 Z

The new coating could be used to create durable, scratch-resistant lenses for eyeglasses, self-cleaning windows, improved solar panels and new medical diagnostic devices, said principal investigator Joanna Aizenberg, who is the Amy Smith Berylson Professor of Materials Science at the Harvard School of Engineering and Applied Sciences (SEAS), a Core Faculty Member at the Wyss Institute for Biologically Inspired Engineering, and Professor of Chemistry and Chemical Biology.

The new coating builds on an award-winning technology that Aizenberg and her team pioneered called Slippery Liquid-Infused Porous Surfaces (SLIPS)—the slipperiest synthetic surface known. The new coating is equally slippery, but more durable and fully transparent. Together these advances solve longstanding challenges in creating commercially useful materials that repel almost everything.SLIPS was inspired by the slick strategy of the carnivorous pitcher plant, which lures insects onto the ultraslippery surface of its leaves, where they slide to their doom. Unlike earlier water-repelling materials, SLIPS repels oil and sticky liquids like honey, and it resists ice formation and bacterial biofilms as well. While SLIPS was an important advance, it was also “a proof of principle”—the first step toward a commercially valuable technology, said lead author Nicolas Vogel, a postdoctoral fellow in applied physics at SEAS.

Air pad that inflates with just a few breaths

Wed, 22 May 2013 00:00:00 Z

If you go camping down in the wild woods, the chances of happening upon a conveniently-placed power outlet for blowing up your mattress with an electric air pump are pretty remote. Unless you have a hand or foot pump in your backpack, you'll have to wrap your lips around a tiny valve that likely has a history of being dragged through all sorts of unmentionable nastiness, and then spend the next long while taking deep breaths and blowing. Ryan Frayne's Windcatcher system inflates in just a few seconds with a valve that never touches your mouth.

The idea is that, when you blow into the gaping mouth of the Windcatcher valve, a stream of fast moving, low pressure air is created. High pressure air round about is attracted to low pressure areas and pulled inside the mattress. Frayne claims that the volume of air entering the Windcatcher system is at least 10 to 15 times greater than that leaving your lungs. Once inside, the valve prevents the air from escaping.

The very fact that the inflation system is so fast makes it a good fit for many indoor/outdoor situations where you might think twice about lugging an air bed around, including lazing in the park, an emergency sleep-over when your flight gets canceled, or camping out for concert tickets.

The Windcatcher system includes a manual override, so you can pull out the invertible release and the air escapes much faster, and more completely, than with a conventional valve. The whole thing can be rolled up to about the size of a liter bottle of water, and secured with Velcro straps.

Self-Repairing Matrices

Tue, 17 May 2011 00:00:00 Z

The fact that structural damage can go undetected in many materials means that some products are often over-engineered. However, substances that can provide information about their internal stresses - as well as trigger reliable self-healing properties - allow manufacturers to be more confident in using lighter weight materials. Self-Repairing and Sensing Matrices can also survive longer than their conventional counterparts, thus reducing the use of virgin materials or petroleum-based resources. Natural Process Design has thus far made airplane wings and other components of this material, which has been successfully tested for flexure, compression, and shear.

One-way soundproofing

Wed, 11 May 2011 00:00:00 Z

Materials that genuinely discriminate between the direction of light or sound might be possible, according to a new study. That could make for true one-way mirrors or for directional soundproofing - imagine, for instance, a wall through which sound can enter but not escape.

Stefano Lepri of the Italian National Research Council and Giulio Casati of the University of Insubria in Italy and the National University of Singapore have worked out the theoretical groundwork for materials that transmit waves in an asymmetric way.

Their proposal relies on the use of nonlinear materials, in which the response of the material depends on the attributes of the wave passing through it. "When you introduce nonlinear interactions and forces, many of the intuitions we have are no longer valid," Lepri told Physical Review Focus, an American Physical Society publication that highlights studies from affiliated journals and explains them to a wider audience. "We can use this nonlinear interaction to break this fundamental result of reciprocity theory," which demands that all waves get the same transmission treatment regardless of the direction from which they arrive.

By stacking layers of nonlinear materials along with ordinary linear layers in an asymmetric fashion, the researchers have calculated, a wave would be able to pass through in one direction but would almost completely bounce off when it arrives from the other direction. The one-way bias isn't universal, however, the researchers note that each particular implementation would have a sweet spot of wave amplitudes and frequencies for which it would work best.

Fight Fire With Flame-Bending Electricity

Mon, 28 Mar 2011 00:00:00 Z

At the 241st National Meeting & Exposition of the American Chemical Society, scientists described a means of suppressing or extinguishing flames without flooding buildings or tapping a vast source of water. Noting a 200-year-old observation that electrical charges can affect the shape of flames, they seized on the phenomenon and developed an electrical wave âblasterâ that could be the basis of a new genre of firefighting tech.

The researchers' setup involves connecting a 600-watt amplifier to a kind of wand that directs the electrical current into a beam. The researchers then created an open flame about a foot high. From a distance, the wand was able to snuff out the flame entirely over and over again.

The process by which it does this is complex, the researchers say, and is actually not really well understood (there are a lot of different things happening at once, apparently). But critically, it seems the carbon particles (soot) generated during combustion are easily charged, and once charged they respond to electric fields in strange ways that affect the stability of the flame. Shake that stability hard enough, and the flame collapses.

Minix

Tue, 22 Feb 2011 00:00:00 Z

What is the vortex and the induced drag ?

This always exists in the parallel direction of the relative wind. It is the main cause of the whirlwinds that appear on the trailing edge: the air passing on the top skin of a wing has a tendency to pass over the lower surface. This is because the pressure on the top skin is lower than the pressure outside of the wing-tips.

On the other hand, the relative wind flows under the outside of the wing because the pressure on the lower surface is greater than the one outside of the wing. The air tries to turn around the wing-tips from the lower surface to the top skin. The way to explain why a higher aspect ratio is better than a shorter one, would be to say that the greater the aspect ratio, the smaller the air quantity escaping outside from the wing-tips is. The air turning around the wing-tip is not useful to produce lift; this is often called "a marginal loss".
As these two airflows, the one from the top skin and the one from the lower surface, meet on the trailing edge at a certain angle, they create whirlwinds turning clockwise (seen from the back) behind the left wing and counter clockwise behind the right wing. All the vortices from the same side have a tendency to gather in order to form a great vortex that escapes from each wing-tip. This is called tip vortex or easer vortex.
Many pilots have seen this vortex or, more precisely, the central part of them that condensation makes perceptible. The air humidity condensates because of the pressure loss in the heart of the vortex. You must not confuse these visible vortices at take-off with those created by the exhaust gas of engines at altitude.
If we now watch the direction of rotation of the vortex we perceive that there is a draught towards the top at the outside of the wing span and a draught downwards behind the trailing edge. You must not confuse this downwards draught with the normal deflexion that occurs. In this last case the deflexion downwards always goes with an upwards deflexion in front of the wing so that the final direction of draught is not modified. But in the case of tip vortex the deflexion occurs upwards outside of the wing and not in front of it, so that the draught leaving the wing is finally directed downwards. By consequence, the lift which is perpendicular to airflow is slowly inclined towards the back and contributes to drag. Result of the vortex, this part of drag is called induced drag.

Other possible applications:
· Airplane wing
· Racers wing
· Glider wing
· U.L.M. wing
· U.A.V wing
· Stabilizing boat wing
· Rudder blade
· Lipp rotor wing
· Submarine airfoil
· Hydrofoil wing
· Hydraglider wing
· Tidal energy wing
· Airfoil racercars, F1
· Windmill blade
· Windmill submarine blade
· Helicopter blade
· Horn Sail, etc...

Photonic: the butterfly model

Thu, 16 Dec 2010 00:00:00 Z

The brightest and most vivid colours in nature arise from the interaction of light with surfaces that exhibit periodic structure on the micro- and nanoscale. In the wings of butterflies, for example, a combination of multilayer interference, optical gratings, photonic crystals and other optical structures gives rise to complex colour mixing. Although the physics of structural colours is well understood, it remains a challenge to create artificial replicas of natural photonic structures. Here we use a combination of layer deposition techniques, including colloidal self-assembly, sputtering and atomic layer deposition, to fabricate photonic structures that mimic the colour mixing effect found on the wings of the Indonesian butterfly Papilio blumei. We also show that a conceptual variation to the natural structure leads to enhanced optical properties. Our approach offers improved efficiency, versatility and scalability compared with previous approaches

Steel Velcro

Thu, 29 Oct 2009 00:00:00 Z

A square metre of the new fastener, called Metaklett, is capable of supporting 35 tonnes at temperatures up to 800 ºC, claim Josef Mair and colleagues at the Technical University of Munich, Germany. And just like everyday Velcro it can be opened up without specialised tools and used again.

Conventional hook-and-loop fasteners are used for everything from bandages to cable boots in aircraft and securing prosthetic limbs. Mair thinks his spring-steel fastener is tough enough to be used for building facades or car assembly. "A car parked in direct sunlight can reach temperatures of 80 °C, and temperatures of several hundred °C can arise around the exhaust manifold," he says, but Metaklett should be able to shrug off such extremes.

The fastening is made from perforated steel strips 0.2 millimetres thick, one kind bristling with springy steel brushes and the other sporting jagged spikes.

Metaklett can support maximum weight when pulled on in the plane of the strips, and a square metre can hold a perpendicular load of 7 tonnes, says Mair.

Energy Generating Speed Bump

Mon, 21 Sep 2009 00:00:00 Z

Fast food lovers may finally feel a little less guilty about getting greasy burgers. One New Jersey Burger King recently equipped its drive-thru with a speed bump that harvests electricity from cars that pass by. The speed bump is part of a pilot project from New Energy Technologies, and if all goes well, drivers could see energy-harvesting speed bumps at drive-thrus, toll plazas and even shopping centers.

The speed bumps, or "MotionPower Energy Harvesters," look much different from your typical concrete humps. The "bump" is actually flat, with long, skinny pedals running across the top. As cars drive over the speed bump, it pushes the pedals down and turns the gears inside. The spinning creates about 2,000 watts of electricity from a car moving at five miles per hour.

Energy created by the cars is instantaneous (like solar and wind power), meaning that speed bump developers must also figure out a way to store power for later use. To that end, developers at New Energy Technologies are currently experimenting with mini-flywheels (a device that stores energy by spinning), and also plan to look into supercapacitors and other energy-storing mechanisms. Eventually, once storage is perfected, the speed bumps could be used to power street lamps or even feed power directly to the grid.

STEAM camera technology

Fri, 29 May 2009 00:00:00 Z

In conventional digital imaging such as CCD and CMOS cameras, the rate at which images are produced is restricted by the time it takes to read data from an array of millions of sensors. Also, as you increase the shutter speed, you are reducing the amount of light that reaches the sensors resulting in images of limited quality. "To put it simply, when you are taking a picture, you can't collect enough light from an object if the exposure time is short," Goda told physicsworld.com.

To get around this compromise, the UCLA researchers have developed a new technology which they refer to as STEAM - "Serial Time-Encoded Amplified Microscopy". STEAM works by freezing images using an optical rather than an electronic process. At its heart, a single-pixel photodiode and oscilloscope capture a stream of one dimensional time-varying data then convert this into high-quality two dimensional images.

Presenting their findings in Nature, the scientists used their camera to record laser ablation - a technique used in surgery to remove targeted areas without damaging near-by tissue. The ablation was performed with a mid-infrared pulse laser focused on a silicon substrate coated with aluminium foil. The camera, normally incident to the substrate surface, was able to capture the particle ejection at a frame rate of 6.1 MHz, where high-end digital cameras can manage only 1kHz.

Knob-Less Doors

Wed, 20 May 2009 00:00:00 Z

Give your entry way a unique look with Albed's modern doors. The Ring Door features no door knobs but instead has volcano-inspired opening with a metal ring inside that controls the opening and closing of the door when pulled.

Along with the Ring Door, Albed also features the Blow Door which has a long, curved handle on either side. These elegant designs will give visitors a pleasant surprise and creates a chic look in any modern home or office.

Feather coating to reduce drag

Wed, 20 May 2009 00:00:00 Z

Coating the rigid wings of airplanes with artificial bristles that mimic feathers could make them more efficient, according to engineers. An Italian team has demonstrated how feather-like structures help reduce drag on a cylinder and says they could have the same effect on underwater and aerial vehicles.

Although they may not look like they can have much of an effect, during gliding some covert feathers stick up at right angles to the wing's surface and vibrate in the airflow. To test whether this has any effect on flight performance Bottaro and Julien Favier, also at Genoa, added synthetic coverts to a computer model of a 20-centimetre-diameter cylinder and put it in a virtual wind tunnel.

Their synthetic feathers are modelled as rigid keratin bristles 4 to 6 centimetres long and 0.5 millimetres in diameter, coating the cylinder at a density of around three fibres per square centimetre. The cylinder was orientated with its long axis perpendicular to the air flow, placing the synthetic feathers parallel to the wind.

As the wind speed increased the bristles started to vibrate in a similar way to real covert feathers, reducing the drag on the cylinder by 15%.
The researchers say that's because the fibres help to cushion the effects of the air flow on the cylinder itself. Normally the air flows rapidly across the cylinder and creates an area of low pressure behind it. This encourages the formation of strong vortices, creating turbulence and increasing the drag on the cylinder.

Anti-reflective coating

Mon, 18 May 2009 00:00:00 Z

Researchers from the FOM Institute for Atomic and Molecular Physics(AMOLF), located at the High Tech Campus in Eindhoven, and PhilipsResearch developed a method to drastically reduce the reflection oflight at the interface between a high refractive index semiconductorand air. The researchers were inspired by the eyes of moths that arecovered by tapered nanostructures. Thanks to these nanostructures,night moths are capable of seeing very well in the dark. The results ofthe research have recently been published in the prestigious journalAdvanced Materials.

Light travels as astraight beam in homogeneous media. The direction of the light beamchanges when it arrives at an interface between two different media. Afraction of light is reflected into the first medium and the rest isrefracted into the second medium. At large angles of incidence at aninterface between air and a solid material such as a semiconductor,nearly 100 % of the light is reflected. Interfaces which reduce thisreflection exist in nature. For example, the eyes of a moth are coveredwith tapered nanostructures, which increase the eye sight of the mothin the dark by allowing more light to enter the eyes.

Inspiredby these biostructures, researchers from AMOLF and Philips Researchdeveloped a method which drastically reduces the reflection between airand a semiconductor. This method consists of the growth of nanowireswith different lengths or with the same length, but conically shaped.Using this method, a gradual change from air to semiconductor isachieved, which leads to an efficient coupling of light into thesemiconductor and minimizes the reflection. These layers show a largereduction of the reflection over a broad range of colors and angles ofincidence. The reduction of the reflection is of importance fordifferent applications. A low reflection can not only increase thesensitivity of a light detector, it can also increase the efficiency ofsolar cells and LEDs. The results of this research are published in theprestigious journal Advanced Materials.

This work is part of the research program of theFoundation for Fundamental Research on Matter (FOM), which isfinancially supported by the Netherlands Organisation for ScientificResearch (NWO) and is part of an industrial partnership program betweenPhilips and FOM.

LIDAR sees which way the wind blows

Mon, 05 Jan 2009 00:00:00 Z

Catch the Wind has developed a LIDAR system called the Vindicator,that could measure the wind speed and direction up to 1000 metres infront of a wind turbine. This allows enough time for the blades toorientate themselves correctly, which will boost the turbine'sefficiency and lifetime.

"The Vindicator system is a new breakthrough for advance measurementfrom a turbine-mounted sensor," Bill Fetzer of Catch the Wind told optics.org."It uses three eye-safe low-power beams to measure the speed anddirection of particulates in the moving airflow in three dimensions."

LIDAR's primary use in this market has been to determine if alocation is suitable for a wind farm, but Catch the Wind believes thatits three-beam LIDAR device would have advantages for this initialdecision too. "A Wind Resource Assessment model of the system canreduce the need for erecting meteorological towers to gather wind dataat potential on-shore and off-shore wind sites," noted Fetzer.

Light moves tiny devices

Wed, 24 Dec 2008 00:00:00 Z

Engineers at Yale University in the US have shown that the force of light can be harnessed to drive nanomachines. The result could lead to all-optical mechanical devices made from nanometre-sized photonic circuits.

The work successfully combines two important emerging fields of research, nanophotonics and nanomechanics, and could make it possible to create tiny optical and mechanical components on the same silicon chip.

Although the force exerted by photons is too weak to be felt in everyday life, it can be greatly enhanced by concentrating light in nanosized photonic circuits.

Until know, the force of light has only been used to move small objects in a technique called "optical tweezers". They work by trapping micrometre-sized objects near the focus of a laser beam. The technique allows objects to be picked up and moved to another place using just light. Now, Hong Tang and colleagues have taken this concept a step further and have shown that optical forces can be exploited to move an entire semiconductor device.

The researchers showed that, when they passed concentrated light through a free-standing nanomechanical photonic resonator, which also acts as a waveguide for light, the resonator bends. The optical force causing this displacement can be measured as a change in the coupling between the resonator and an underlying substrate. The force (which can be as high as 8 pN per micron per milliwatt) would be large enough to move nanoscale machinery on a chip, say Tang and colleagues.
The optical force produced in the new method actually acts perpendicular to the direction of the light beam. This is in contrast to previous systems where the optical force was parallel to the direction of light propagation. This now means that mirrors or cavity configurations, which are difficult to implement in integrated chip-scale systems, are no longer required. And that's not all: the light force is intrinsically fast and can thus drive nanomechanical devices at very high frequencies, possibly surpassing the current milestone of a few gigahertz,

broadband invisibility cloaks

Wed, 24 Dec 2008 00:00:00 Z

Two years ago researchers at Duke University in the US unveiled the first "invisibility cloak", a device that can make objects vanish from sight, at least when viewed using a narrow band of microwave frequencies. Such cloaks work by causing electromagnetic waves to flow smoothly around the object and recombine on the other side in such a way as to make it appear that the waves travelled straight through the object unhindered.
Since then physicists have struggled to create cloaks that work across a wider range of frequencies and could be used, for example, to hide an object from radar. Now, Ulf Leonhardt of St Andrew's University in the UK and Tomás Tyc of Masaryk University in the Czech Republic have come up with a new way of using mathematics to describe a invisibility cloak, a breakthrough that the physicists say could lead to the development of broadband invisibility cloaks

From a mathematical point of view, an invisibility cloak can be described as a transformation of flat space that makes the light follow a curved path around the object. The idea is to make a coordinate transformation that takes a point in space and expands it into a sphere, the interior of which is invisible to an observer on the outside. For this to work light must traverse the surface of the sphere in the same, infinitesimally short time it would take to pass the original point. As a result, the light must travel at an infinitely high speed on the surface of the sphere.

Amazingly, the phase velocity of light can approach infinity in some materials and metamaterials (without violating the special theory of relativity because the "signal velocity" remains the speed of light). This has allowed the Duke team and others to actually build invisibility cloaks. The problem, however, is this only occurs for light at certain resonant frequencies.

Leonhardt and Tyc made their theoretical breakthrough by using non-Euclidean geometry to describe the workings of their cloak. Unlike the more familiar Euclidean geometry, non-Euclidean geometry is not restricted to describing space in terms of perpendicular axes. In their work, the physicists used a non-Euclidean geometry based on the surface of a sphere, which they intersected with a Euclidean plane in an arrangement that resembles a globe partially wrapped by a piece of paper (see figure).

The plane represents the region away from the cloak containing the light source and the observer, while the spherical geometry contains the region to be cloaked. If the sphere is between the source and observer, some of the light from the source will travel from the plane onto the sphere, where the light will naturally follows a curved path.

However, because of the way that the plane intersects the sphere, there is a small region on the sphere that these curved paths don't cross. The trick, according to Leonhardt and Tyc, is to use a coordinate transformation to expand this into a space that could enclose a cloaked object. Because this does not involve expanding an infinitesimally small point, it does not require the light to travel at an infinitely high speed. This means that the operation of the cloak is no longer dependent on resonances in the material and should therefore work over a wider range of frequencies

While the physicists haven't actually built such a cloak, they say that there non-Euclidean approach could provide a blueprint for building a broadband cloak. In particular, it could be used to define the index of refraction at a specific point in the cloak, and for light travelling in a specific direction. This quantity is given by the ratio by which the transformation stretches space at that point to create the cloaked region.

T-Rays

Fri, 19 Dec 2008 00:00:00 Z

Terahertz radiation, or T-rays,occur at a frequency of around a trillion hertz, between microwaves andinfrared on the electromagnetic spectrum. Unlike X-rays, T-rays arenonionizing, so they don't carry a cancer risk. They can penetrateclothing, packaging and a few millimeters into the human body, makingthem ideal for security screening and medical applications such asskin-cancer and tooth-cavity detection. Until now, they've beendifficult to generate, but Harvard researchers recently filed for apatent on the first room-temperature source of coherent T-rays, andscientists at Argonne National Laboratory are developing a portableT-ray generator. Lower-resolution passive detection systems that pickup natural T-ray emissions are already on the market: The Wayne CountySheriff's Office, in Detroit, is testing a scanner built by Britishcompany ThruVision to screen anyone entering its criminal courts.

A New Focus for Light

Fri, 19 Dec 2008 00:00:00 Z

Researchers trying to make high-capacity DVDs, as well as more-powerfulcomputer chips and higher-resolution optical microscopes, have foryears run up against the "diffraction limit." The laws of physicsdictate that the lenses used to direct light beams cannot focus themonto a spot whose diameter is less than half the light's wavelength.Physicists have been able to get around the diffraction limit in thelab--but the systems they've devised have been too fragile andcomplicated for practical use. Now Harvard University electricalengineers led by Kenneth Crozier and Federico Capasso have discovered asimple process that could bring the benefits of tightly focused lightbeams to commercial applications. By adding nanoscale "opticalantennas" to a commercially available laser, Crozier and Capasso havefocused infrared light onto a spot just 40 nanometerswide--one-twentieth the light's wavelength. Such optical antennascould one day make possible DVD-like discs that store 3.6 terabytes ofdata--the equivalent of more than 750 of today's 4.7-gigabyterecordable DVDs.