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Exploring Chaos, Fractals and Bifurcation

Exploring Chaos, Fractals and Bifurcation | Physics | Scoop.it
As you may have seen, I am currently really enjoying a course on Dynamic Systems and Chaos run by Santa Fe Institute (see Thoughts on Santa Fe’s new MOOC – Introduction to Dynamical Systems and Cha...

Via Bernard Ryefield
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Fascinating. "...we begin to really grasp the extraordinary complex and chaotic behaviour of what we thought may be an innocuous looking equation. As well as the fractal like patterns, we also notice structure within the chaos..."

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Magnets for fusion energy: A revolutionary manufacturing method developed

Magnets for fusion energy: A revolutionary manufacturing method developed | Physics | Scoop.it
The National Institute for Fusion Science (NIFS), of the National Institutes of Natural Sciences (NINS) in Japan, has achieved an electrical current of 100,000 amperes, which is by far the highest in the world, by using the new idea of assembling...

Via tmertzi
Mikko Hakala's insight:

World-record electrical current demonstrated, 100 000 A, obtained with stacked yttrium-based superconducting tapes. Superconductors are the only viable option, since they can carry large dissipationless electrical currents.

 

As electrical current creates a magnetic field, superconductors can be used to create strong magnets. These in turn are needed in fusion reactors to control the plasma, in medical instruments and in power-electronics devices.

 

A short article explaining the achievement and two good illustrations. 

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Perovskite Solar Cell Technology of Oxford PV, The Potential Game-Changer | Sun Is The Future

Perovskite Solar Cell Technology of Oxford PV, The Potential Game-Changer | Sun Is The Future | Physics | Scoop.it
Dear Friends, Visitors/Viewers/Readers, (Please click on red links and note magenta) At InterSolar North America 2014 in San Francisco, CA, I came across
Mikko Hakala's insight:

 

Solar cell technology based on perovskites

 

Useful info in the post and interview on Oxford PV activities in this field. In the video Dr. Christopher Case describes the material and its applications in various ways in solar cell technologies. Here's my quick summary of the video's content:

 

0:45 Fastest increasing photovoltaic efficiency 

1:15 Thin film material

1:35 Applications, initial view of the company was to develop semi-transparent coatings

2:10 Can be made in almost any color

3:00 New application of perovskites: tandem solar cells (perovskite coating on conventional Si)

4:10 What are perovskites

4:45 How to tailor the properties

5:10 Material itself studied already for decades

5:50 Finding the planar form by Prof. Snaith was a breakthrough

6:40 More and more papers coming out on this material

6:55 Perovskite on Si solar cells boosts efficiency, easier to make this product than a fully integrated PV

7:40 Perovskites fundamentally and perspectives for efficiency

8:15 Potential to replace Si?

8:40 About processing: it's solution processed from inexpensive materials

9:30 Future steps. Towards full perovskite-on-perovskite tandem cells

9:50 How to get in contact, what their company's website contains

 

 

 

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Surrey NanoSystems has "super black" material

Surrey NanoSystems has "super black" material | Physics | Scoop.it
(Phys.org) —A British company says it has scored a breakthrough in the world's darkest material. Surrey NanoSystems describes its development as not just a black material but super-black. They are calling it Vantablack, and they are singling out its ability to be applied to lightweight, temperature-sensitive ...
Mikko Hakala's insight:

Here is the ultimate black. This coating material is made from carbon nanotubes, with promising applications for example for telescopes.

 

There are also nice physics discussions in the comments.

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Supercomputers reveal strange, stress-induced transformations in world's thinnest materials

Supercomputers reveal strange, stress-induced transformations in world's thinnest materials | Physics | Scoop.it
(Phys.org) —Interested in an ultra-fast, unbreakable, and flexible smart phone that recharges in a matter of seconds? Monolayer materials may make it possible. These atom-thin sheets—including the famed super material graphene—feature exceptional and untapped mechanical and electronic properties. ...
Mikko Hakala's insight:

Behavior under stress of 4 novel monolayer materials studied (graphene, graphane, BN, MOS2), by density functional theory calculations.

 

By these simulations researchers identified a common soft (vibrational) mode failure mechanism that leads to the eventual breaking of these 2D-materials under stress. 

 

The article has a useful 'Key Takeaways' section in the end.

 

 

 

 

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Upgrade for European light source

Upgrade for European light source | Physics | Scoop.it

European Synchrotron Radiation Facility (ESRF). One of Europe's premier scientific research laboratories is to go through a major upgrade.


Via tmertzi
Mikko Hakala's insight:

 

European Synchrotron Radiation Facility (ESRF) is a most powerful X-ray machine in Europe, supported and shared by 20 countries. See http://www.esrf.eu/ ;

 

ESRF is going through a major upgrade. This BBC article by @BBCAmos (via @tmertzi) tells some essential information what this means to ESRF. See how much more radiation will be obtained, how much will the upgrade cost and the timetables.

 

How synchrotron X-rays are generated and how research is done with them? Here is one recent video from a canadian synchrotron explaining basic operation:

http://globalnews.ca/video/1439365/synchrotron-matters

(via @CanLightSource, @lightsources)

 

Follow ESRF in Twitter: @esrfsynchrotron

 

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Rescooped by Mikko Hakala from Science: resources for South African teachers
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▶ How Chemistry Creates Really Big Bubbles | Outrageous Acts of Science - YouTube

Everyone loves bubbles... but you've never seen them quite like this. Great video for introducing surface tension.


Via Andrew van Zyl
Mikko Hakala's insight:

What keeps the bubble from bursting? Learn about

 

* the role of surface tension

* how to lower it

* how to avoid water evaporation

 

2 minute video.

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Shatterproof screens that save smartphones

Shatterproof screens that save smartphones | Physics | Scoop.it
University of Akron polymer scientists have developed a transparent electrode that could change the face of smartphones, literally, by making their displays shatterproof.
Mikko Hakala's insight:

Current touch displays are capacitive and they need transparent conducting layers as part of the structure. ITO (indium tin oxide) glass is the most often used technology for these layers. However, it is costly and brittle, so alternatives are sought. 

 

This article presents a metal-nanowire based alternative film, which has better properties than ITO (better conductivity and flexibility). There are also other alternatives, for example based on carbon nanotubes or polymers. These kind of findings are potentially important since there seems to be big a market to replace ITO.

 

An excellent explanation (5 pages) of the technology of touch screens can be found here: http://www.computerworld.com/s/article/9231961/How_it_works_The_technology_of_touch_screens

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Team first to detect exciton in metal

Team first to detect exciton in metal | Physics | Scoop.it
University of Pittsburgh researchers have become the first to detect a fundamental particle of light-matter interaction in metals, the exciton. The team will publish its work online June 1 in Nature Physics.
Mikko Hakala's insight:

Observation of excitons in metals is difficult due to their short lifetimes. This research reports detection on metal surfaces via multiphoton photoemission.

 

Quick info on excitons: http://en.wikipedia.org/wiki/Exciton

 

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Design and synthesis of the first triply twisted Möbius annulene : Nature Chemistry : Nature Publishing Group

Design and synthesis of the first triply twisted Möbius annulene : Nature Chemistry : Nature Publishing Group | Physics | Scoop.it
Most cyclic conjugated molecules, such as benzene, exhibit two sides. Möbius annulenes, however, with an odd number of 180° twists in their π system are one-sided and violate the Hückel rule. Now, using a topological trick it is demonstrated that triply twisted systems are not particularly strained and probably easier to synthesize than singly twisted ones.
Mikko Hakala's insight:

Topology and chemistry combined: Annulene in a Möbius ring configuration with three twists. Applications could be found in optoelectronics and nanotechnology.

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New insight into the temperature of deep Earth

New insight into the temperature of deep Earth | Physics | Scoop.it
Scientists from the Magma and Volcanoes Laboratory (CNRS) and the European Synchrotron, the ESRF, have recreated the extreme conditions 600 to 2900 km below the Earth's surface to investigate the melting of basalt in the oceanic tectonic plates. They exposed microscopic pieces of rock to these extreme ...
Mikko Hakala's insight:

135 GPa and 3800 K conditions prepared at the laboratory scale, to study the melting behaviour of geological materials in the Earth's mantle. The article gives a glimpse on some current issues and investigations.

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Astronomers create first realistic virtual universe

Astronomers create first realistic virtual universe | Physics | Scoop.it
Move over, Matrix - astronomers have done you one better. They have created the first realistic virtual universe using a computer simulation called 'Illustris.' Illustris can recreate 13 billion years of cosmic evolution in a cube 350 million light-years on a side with unprecedented resolution.
Mikko Hakala's insight:

Impressive. The simulation is said to model both the chemistries of individual galaxies and the large-scale structures (galaxy clusters, bubbles and voids of the cosmic web).

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Breakthrough in Study of High-Temperature Superconductivity | Simons Foundation

Breakthrough in Study of High-Temperature Superconductivity | Simons Foundation | Physics | Scoop.it
Experimentalists have pinpointed the microscopic structure of waves inside high-temperature superconductors, which could be the key to understanding the complex materials.
Mikko Hakala's insight:

An interesting, broad and detailed article about the current advancements in understanding the microscopic origin of superconductivity in cuprates. 

 

The article discusses recent findings by various groups. In particlar, it addresses the details of the d-wave charge density order, and how antiferromagnetism is the parent state both to superconductivity and to charge density waves.

 

Challenges remain, for example "[a recently proposed theoretical framework] is not yet refined enough to predict how the balance of charge density waves and superconductivity vary with temperature, magnetic field or type of cuprate."

 

In short, this is a clarifying expert article on a specific condensed matter topic, the origin of d-wave superconductivity and the nature of charge density waves in cuprates.

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High-temperature superconductivity in the iron pnictides

High-temperature superconductivity in the iron pnictides | Physics | Scoop.it
Mikko Hakala's insight:

Here is a set of resources for iron pnictides.

 

* Focus article by M. R. Norman, 2008 (the main link) 

http://physics.aps.org/articles/v1/21

 

* Some recent studies

http://phys.org/news/2013-12-iron-age-high-temperature-superconductivity.html

http://www.emfl.eu/research/highlights/pnictides-go-critical.html

http://www.annualreviews.org/doi/abs/10.1146/annurev-conmatphys-031113-133921

http://phys.org/news/2013-11-infrared-gap-iron-based-superconductor.html

 

* Groups

http://arpes.stanford.edu/research_fe_pnictides.html

http://www.stanford.edu/group/fisher/research/Fe_pnictides.html

 

 

 

 

 

 

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The Science of Lightning

The Science of Lightning | Physics | Scoop.it
A view into some of the rarer types of lightning
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Have you heard of dark, volcanic or alien lightning?


Some lesser known aspects of lightning in this short popular science article. Lightning is an active reserch topic in atmospheric science.


via +Jenny Winder

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Ten kinds of matter

A cool discovery: substances can be divided into 10 kinds.…

Ten kinds of matter<br/><br/>A cool discovery: substances can be divided into 10 kinds.… | Physics | Scoop.it
Ten kinds of matter

A cool discovery: substances can be divided into 10 kinds.

The basic idea is pretty simple.  Some substances have time-reversal… - John Baez - Google+
Mikko Hakala's insight:

Theoretical condensed matter physics in Google+.

 

By looking at the symmetries of substances, 10 different kinds of matter can be found. Discussion of the issue in the main post and more in the comments thread. Post by +John Baez.

 

via +Jari Vasell

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First Ab Initio Method for Characterizing Hot Carriers Could Hold the Key to Future Solar Cell Efficiencies

First Ab Initio Method for Characterizing Hot Carriers Could Hold the Key to Future Solar Cell Efficiencies | Physics | Scoop.it
Berkeley Lab researchers have developed the first ab initio method for characterizing the properties of “hot carriers” in semiconductors. This should help clear a major road block to the development of new, more efficient solar cells.
Mikko Hakala's insight:

 

Computer simulations for hot carriers in solar cell  

 

* These are first steps towards ab initio characterization of hot carriers in solar cell absorber materials. The approach is density functional and many body perturbation theory, requiring only the structure as input.

 

* Electron-electron and electron-phonon loss mechanisms are evaluated, and predictions are given for the life time and mean free path of the hot charge carriers in silicon.


* It's an important work since thermalization of hot carriers is hard to evaluate but is the main efficiency-limiting mechanism in solar cells. Now these are first steps to predict this phenomenon purely ab initio. The method will help design and engineer more performant crystalline solar cell absorbers.  


* The PRL article:

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.257402

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NASA rover's images show laser flash on martian rock (w/ Video)

NASA rover's images show laser flash on martian rock (w/ Video) | Physics | Scoop.it
(Phys.org) —Flashes appear on a baseball-size Martian rock in a series of images taken Saturday, July 12 by the Mars Hand Lens Imager (MAHLI) camera on the arm of NASA's Curiosity Mars Rover. The flashes occurred while the rover's Chemistry and Camera (ChemCam) instrument fired multiple laser shots ...
Mikko Hakala's insight:

Spectrosccopic analysis of the Martian rocks after laser shots. 

 

More info:

http://phys.org/news/2013-12-martian-laser-surpasses-zaps.html

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The Little-Known Scientific Reason Your iPhone Earbuds Always Get Tangled

The Little-Known Scientific Reason Your iPhone Earbuds Always Get Tangled | Physics | Scoop.it
Knots really do form on their own as a matter of physics, not because of your personal lack of neatness.
Mikko Hakala's insight:

A perfect everyday physics article - Must read. 

 

Via @DoTryThisAtHome

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Ionic liquid boosts efficiency of CO2 reduction catalyst

Ionic liquid boosts efficiency of CO2 reduction catalyst | Physics | Scoop.it
(Phys.org) —Wouldn't it be nice to use solar- or wind-generated electricity to turn excess carbon dioxide—one of the gases trapping heat in Earth's atmosphere—into fuels and other useful chemicals? The process would store up the intermittent solar or wind energy in a form that could be used when ...
Mikko Hakala's insight:

How to reduce excess CO2 in the atmosphere? CO2 is one of the culprits for the greenhouse effect.

 

The research described in this Phys.org article used ionic liquid as a reaction medium for CO2 and the catalyst. The purpose is to reduce CO2 to CO, which can be further converted to more useful forms. The setup with ionic liquids was found to be better for the speed of the reaction and energy efficiency. Ionic liquids themselves are novel, tailorable liquids, and have promise to replace traditional solvents.

 

The work shows that there is progress in efforts for CO2 reduction, but apparently rather slowly. The basic fundamental research could play here a key role: The 'unknown' in the whole process is that one doesn't know exactly how the chemical reaction happens. That means that one doesn't know clearly what to modify in the process to make it happen easier (that is, how to lower the activation barrier for the reaction).

 

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Free Educational Physics Lecture Videos with Lecture Notes

Free Educational Physics Lecture Videos with Lecture Notes | Physics | Scoop.it
After teaching physics in a high school classroom for 13 years, I stepped out of the classroom to start Flipping Physics, a business dedicated to creating free, clear, concise and comedic physics educational videos.
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A nice and fun set of physics lecture videos. Many topics are covered, for example mechanics, electromagnetism, electrical circuits, refraction, interference. Some lectures also on modern physics.

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High-Tc superconductors: key similarities and differences between electron- and hole-doped cuprates unveiled by X-rays

High-Tc superconductors: key similarities and differences between electron- and hole-doped cuprates unveiled by X-rays | Physics | Scoop.it
Mikko Hakala's insight:

Experimental studies for the spin and charge excitations in doped cuprates. Insight into the energy - wavevector relation of the excitations is important since spin fluctuations are connected to the superconductivity in cuprates. These high-resolution resonant inelastic X-ray studies are an alternative to neutron scattering to investigate spin dynamics.

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Scientists discover new magnetic phase in iron-based superconductors

Scientists discover new magnetic phase in iron-based superconductors | Physics | Scoop.it
(Phys.org) —Scientists at the U.S. Department of Energy's Argonne National Laboratory have discovered a previously unknown phase in a class of superconductors called iron arsenides. This sheds light on a debate over the interactions between atoms and electrons that are responsible for their unusual ...
Mikko Hakala's insight:

More research on iron-based superconductors (http://sco.lt/7CfptR), here on doped barium iron arsenide. The electron pairing mechanism is not understood in these unconventional superconductors. To elucidate the mechanism, one issue is to map out the precise phase diagrams.


Here neutron diffraction showed that on lowering the temperature, close to the onset of superconductivity, the structure restores 4-fold symmetry. At higher temperatures the structure has nematic ("thread-like") order with 2-fold symmetry, whereas at room temperature the symmetry is again 4-fold.


The finding appears to support the model that the nematic phase is driven by magnetic interactions and not by iron 3d orbital ordering. And this hints, according to the phys.org article, that it could be magnetism that could be the key to electron pairing. 


Pin it for later:

http://www.pinterest.com/pin/318981586080372229/


The Nature Communications article:

http://www.nature.com/ncomms/2014/140522/ncomms4845/full/ncomms4845.html


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Solution to two long-standing mysteries of cuprate superconductivity found

Solution to two long-standing mysteries of cuprate superconductivity found | Physics | Scoop.it
Scientists seeking to understand the intricacies of high-temperature superconductivity—the ability of certain materials to carry electrical current with no energy loss—have been particularly puzzled by a mysterious phase that emerges as charge carriers are added that appears to compete with superconductivity. ...
Mikko Hakala's insight:

More on the superconductivity of cuprates (see http://sco.lt/5pcQjZ).

 

At low hole doping, i.e. at the pseudogap phase, the static electron arrangement (charge density wave or "frozen" stripe patterns) and the associated nanoscale fluctuations prevent the free flow of electrons. At higher hole doping the density wave disappears and unrestricted superconductivity appears.

 

Measurements by spectroscopic imaging scanning tunneling microscope.

 

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Scientists find X-rays can cause reversible resistance changes

Scientists find X-rays can cause reversible resistance changes | Physics | Scoop.it
(Phys.org) —Usually, when we think of a device that has defects, it means it's time to throw it out. However, for several types of materials, imperfections are what actually make them function in the first place. Finding ways to control defects in a material without irrevocably damaging it could yield ...
Mikko Hakala's insight:

In addition to X-rays being a great diagnostic tool for microscopic and long-range atomic and electronic structures, this study says they can also trigger controlled resistive switching in TiO2 (that is, changes in electrical resistance) by orders of magnitude.    

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Physicists discover how to change the crystal structure of graphene

Physicists discover how to change the crystal structure of graphene | Physics | Scoop.it
A University of Arizona-led team of physicists has discovered how to change the crystal structure of graphene, more commonly known as pencil lead, with an electric field, an important step toward the possible use of graphene in microprocessors that would be smaller and faster than current, silicon-based ...
Mikko Hakala's insight:

The paper shows that the stacking of graphene layers (in a 3-layer case) can be controlled with an external voltage. This way one obtains either metallic or semiconducting behavior. According to the article, for the first time such on-off switch is demonstrated in graphene.

 

This is in early stages but could become very important if the tuning of graphene's electrical properties can be realized at larger scale. The ultimate aim is a graphene-based transistor, with huge advantages compared to silicon-based ones.

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