Archive for the ‘Physics’ Category

Seventeen equations that changed the world

March 20, 2014

I just came across this summarising Ian Stewart’s book on 17 Equations That Changed The World at Business Insider: 

seventeen equations

seventeen equations

I have used all of these up to Equation 12. I have never used the equations on Relativity or Schrodinger’s equation or those on Chaos or Information theory or the Black-Scholes Equation. But, I wouldn’t disagree with Equations 12 – 17, but considering the amount of time I spent applying it at University and during my working life I would have liked to see Bernoulli’s Equation on the list:

Bernoulli's Equation

where:

v\, is the fluid flow speed at a point on a streamline,
g\, is the acceleration due to gravity,
z\, is the elevation of the point above a reference plane, with the positive z-direction pointing upward – so in the direction opposite to the gravitational acceleration,
p\, is the pressure at the chosen point, and
\rho\, is the density of the fluid at all points in the fluid.

Going nuclear for a nanowatt battery life of 20+ years

February 28, 2014

Tritium batteries are now available commercially and can have a life exceeding 20 years (Tritium has a half-life of 12.3 years). These thumb-size batteries can produce enough nanowatt (1 nW = 10−9 watt) power to keep micro-electronics going. An 8-bit PIC microcontroller chip when in “sleep” mode consumes around 10 nW. The cost is still in thousands of Dollars but should come down fast. It appears that they could be scaled up to the microwatt (1 µW = 10−6 watt) range which would be enough to power a wristwatch.

Commercial nanoTritium battery by City Labs

Commercial nanoTritium battery by City Labs

Tritium (symbol T or 3H, also known as hydrogen-3) is a radioactive isotope of hydrogen. The nucleusof tritium (sometimes called a triton) contains one proton and two neutrons, whereas the nucleus of protium (by far the most abundant hydrogen isotope) contains one proton and no neutrons. Naturally occurring tritium is extremely rare on Earth, where trace amounts are formed by the interaction of the atmosphere with cosmic rays. The name of this isotope is formed from the Greek word “tritos” meaning “third”.

Tritium is produced in nuclear reactors by neutron activation of lithium-6. This is possible with neutrons of any energy, and is an exothermic reaction yielding 4.8 MeV. In comparison, the fusion of deuterium with tritium releases about 17.6 MeV of energy. High-energy neutrons can also produce tritium from lithium-7 in an endothermic reaction, consuming 2.466 MeV. This was discovered when the 1954 Castle Bravo nuclear test produced an unexpectedly high yield.

Gizmag reports:

(Tritium) although occurring naturally in the upper atmosphere, it’s also produced commercially in nuclear reactors and used in such self-luminescent products as aircraft dials, gauges, luminous paints, exit signs in buildings and wristwatches. It’s also considered a relatively benign betavoltaic, providing a continuous flow of low-powered electrons for a good many years.

According to the Environmental Protection Agency, tritium has a half-life of 12.3 years and the Model P100a NanoTritium betavoltaic power source from Toronto’s City Labs is claimed to be capable of providing juice to low-power micro-electronic and sensor applications for over 20 years. It’s described as robust and hermetically sealed, and the tritium is incorporated in solid form.

Independent testing undertaken by Lockheed Martin during an industry-wide survey also found the technology to be resistant to broad temperature extremes (-50° C to 150° C/-58° F to 302° F), as well as extreme vibration and altitude.

Examples of possible applications for the technology offered by City Labs include environmental pressure/temperature sensors, intelligence sensors, medical implants, trickle charging lithium batteries, semi-passive and active RFID tags, deep space probes, silicon clocks, SRAM memory backup, deep-sea oil well electronics, and lower power processors.

It is still a long way from microwatts to the kilowatts needed to power a home or to drive electric vehicles and the Megawatts needed for small scale power generation. Central power generation requires Gigawatts.

It is easier to convert nuclear radiation into heat and only some materials are betavoltaics which generate current. If only all low-grade radioactive waste from nuclear plants could be converted into batteries! Perhaps nuclear batteries are the breakthrough that electric cars are waiting for!! With current battery technology they are not going anywhere very fast.

Academic backstabbing, misconduct, conspiracy and much, much more at Purdue University

February 7, 2014

The Purdue University School of Nuclear Engineering is the unlikely location for a tangled, sordid tale which I cannot make much sense of.

Professor Rusi Taleyarkhan is either a somewhat naive victim of a nasty conspiracy or he is guilty of academic misconduct and has received his just deserts. But his primary anatgonist was Professor Lefteri Tsoukalas once the head of the School of Nuclear Engineering but who was forced to resign as head by Purdue. Purdue removed Taleyarkhan’s endowed professorship, reduced his salary, and limited his duties with students. There is a murky connection between a journalist Eugenie Reich and Tsoukalas while Reich was promoting her book about scientific misconduct and there was some form of cooperation between them and a number of others to accuse Taleyarkhan.

Once I got this far I gave up.

There is quite obviously a great deal of muck in the Purdue University School of Nuclear Engineering. The University is probably vacillating between support for the warring academics. The role of  the journalist is what adds to the possibility of a nasty conspiracy.

It seems too tawdry to waste much time on though, of course, some careers are being destroyed and someone is – or both are – indulging in defamation.

The New Energy Times has a whole series of articles on the subject. They seem to feel that Talayarkhan has been badly wronged. This article in TwoCircles also takes that position. Tsoukalas puts his position in a letter provided to the New York Times (in 2007).

Oh what a tangled web they weave. It’s all about low-energy, table-top fusion — so it is all probably a hurricane in a thimble. I cannot help observing that cold fusion and claims of misconduct generally seem to go hand-in-hand!

“Black holes don’t exist” – Hawking applied to climate

February 3, 2014

Stephen Hawking’s recent paper is causing much consternation as Geraint Lewis describes in  The Conversation.

But could it be that it is Hawking’s non-existent black holes – located at the bottom of the oceans – which have swallowed up all the heat predicted by climate models and which has gone missing?

Grey is the new black hole: is Stephen Hawking right?

Over the past few days, the media has cried out the recent proclamation from Stephen Hawking that black holes, a mystery of both science and science fiction, do not exist.

Such statements send social media into conniptions, and comments quickly degenerate into satirical discussions of how you should never believe anything scientists say, as they just make it up anyway.

S. W. Hawking, Information Preservation and Weather Forecasting for Black Holes, arXiv:1401.5761v1

Abstract: It has been suggested [1] that the resolution of the information paradox for evaporating black holes is that the holes are surrounded by firewalls, bolts of outgoing radiation that would destroy any infalling observer. Such firewalls would break the CPT invariance of quantum gravity and seem to be ruled out on other grounds. A different resolution of the paradox is proposed, namely that gravitational collapse produces apparent horizons but no event horizons behind which information is lost. This proposal is supported by ADS-CFT and is the only resolution of the paradox compatible with CPT. The collapse to form a black hole will in general be chaotic and the dual CFT on the boundary of ADS will be turbulent. Thus, like weather forecasting on Earth, information will effectively be lost, although there would be no loss of unitarity.

But while Geraint Lewis considers whether “black” is actually “grey”, I think it is no more complicated than a zero-sum game of arcane physics. Whereas zero divided by zero may be indeterminate it seems to me that zero multiplied by zero must be a double zero.

Apart from the obvious that a “black hole” – by its very naming – must therefore mean a double-dose of nothingness it is worth noting that Hawking – being the ultimate authority for Sheldon Cooper – distinguishes between “apparent horizons” which are not real “event horizons” and that he compares the chaos of collapse to a black hole to “weather forecasting”!!

Or did he mean “climate forecasts” and “climate modelling”? After all the hidden heat could well have been swallowed up into the fathomless pit of climatic black holes.

Maybe the abstract should read:

Chaotic climate and the black holes of climate modelling

It has been suggested that the resolution of the climate paradox for hidden heat is that the oceans are surrounded by firewalls, bolts of outgoing radiation that would destroy any infalling climatologist. Such firewalls would break the fundamental laws of thermodynamics and seem to be ruled out on other grounds. A different resolution of the paradox is proposed, namely that climate models produces apparent warming but the warming is a negative warming where heat is lost. This proposal is supported by the reality of the hiatus in global temperatures and is the only resolution of the paradox compatible with CS (common sense). The collapse to enter the new glacial will in general be chaotic and the approach of such a condition will be turbulent. Thus, like weather forecasting on Earth, information will effectively be lost, although there would be no loss of unitarity.

From graphene to borophene

January 29, 2014

Technology development waves

The discovery of graphene is leading to a new excitement in materials research. I have a notion that technology advances take place in step waves, where each step is both enabled and constrained by the materials available. Each time a new material (or material family is discovered), technology development starts very fast and then tapers off until another material comes along and ignites a new development wave.

Boron is Carbon’s neighbour in the periodic table and the discovery of graphene has ignited studies to see if a similar variation of boron would be possible.

Boron is a Group 13 element that has properties which are borderline between metals and non-metals (semimetallic). It is a semiconductor rather than a metallic conductor. Chemically it is closer to silicon than to aluminium, gallium, indium, and thallium. Crystalline boron is inert chemically and is resistant to attack by boiling HF or HCl. When finely divided it is attacked slowly by hot concentrated nitric acid.

Boron, Symbol: B, Atomic number: 5, Atomic weight: 10.811, solid at 298 K

“Boron has one fewer electron than carbon and as a result can’t form the honeycomb lattice that makes up graphene. For boron to form a single-atom layer, theorists suggested that the atoms must be arranged in a triangular lattice with hexagonal vacancies — holes — in the lattice.”

A new paper shows that borophene is possible – now it just has to be made!

Zachary A. Piazza, Han-Shi Hu, Wei-Li Li, Ya-Fan Zhao, Jun Li, Lai-Sheng Wang.Planar hexagonal B36 as a potential basis for extended single-atom layer boron sheetsNature Communications, 2014; 5 DOI: 10.1038/ncomms4113

Brown University Press Release:

Unlocking the secrets of the B36 cluster
A 36-atom cluster of boron, left, arranged as a flat disc with a hexagonal hole in the middle, fits the theoretical requirements for making a one-atom-thick boron sheet, right, a theoretical nanomaterial dubbed “borophene.” Credit: Wang lab/Brown University

Graphene, a sheet of carbon one atom thick, may soon have a new nanomaterial partner. In the lab and on supercomputers, chemical engineers have determined that a unique arrangement of 36 boron atoms in a flat disc with a hexagonal hole in the middle may be the preferred building blocks for “borophene.”

Researchers from Brown University have shown experimentally that a boron-based competitor to graphene is a very real possibility.

Lai-Sheng Wang, professor of chemistry at Brown and his research group, which has studied boron chemistry for many years, have now produced the first experimental evidence that such a structure is possible. In a paper published on January 20 in Nature Communications, Wang and his team showed that a cluster made of 36 boron atoms (B36) forms a symmetrical, one-atom thick disc with a perfect hexagonal hole in the middle.

“It’s beautiful,” Wang said. “It has exact hexagonal symmetry with the hexagonal hole we were looking for. The hole is of real significance here. It suggests that this theoretical calculation about a boron planar structure might be right.”

It may be possible, Wang said, to use B36 basis to form an extended planar boron sheet. In other words, B36 may well be the embryo of a new nanomaterial that Wang and his team have dubbed “borophene.”

“We still only have one unit,” Wang said. “We haven’t made borophene yet, but this work suggests that this structure is more than just a calculation.” ……..

Wang’s experiments showed that the B36 cluster was something special. It had an extremely low electron binding energy compared to other boron clusters. The shape of the cluster’s binding spectrum also suggested that it was a symmetrical structure. ……..

…… That structure also fits the theoretical requirements for making borophene, which is an extremely interesting prospect, Wang said. The boron-boron bond is very strong, nearly as strong as the carbon-carbon bond. So borophene should be very strong. Its electrical properties may be even more interesting. Borophene is predicted to be fully metallic, whereas graphene is a semi-metal. That means borophene might end up being a better conductor than graphene.

“That is,” Wang cautions, “if anyone can make it.”

AbstractBoron is carbon’s neighbour in the periodic table and has similar valence orbitals. However, boron cannot form graphene-like structures with a honeycomb hexagonal framework because of its electron deficiency. Computational studies suggest that extended boron sheets with partially filled hexagonal holes are stable; however, there has been no experimental evidence for such atom-thin boron nanostructures. Here, we show experimentally and theoretically that B36 is a highly stable quasiplanar boron cluster with a central hexagonal hole, providing the first experimental evidence that single-atom layer boron sheets with hexagonal vacancies are potentially viable. Photoelectron spectroscopy of B36 reveals a relatively simple spectrum, suggesting a symmetric cluster. Global minimum searches for B36 lead to a quasiplanar structure with a central hexagonal hole. Neutral B36 is the smallest boron cluster to have sixfold symmetry and a perfect hexagonal vacancy, and it can be viewed as a potential basis for extended two-dimensional boron sheets.

An infinite and timeless universe measured with an accuracy of 1%!

January 10, 2014

A new paper has been capturing some headlines. It is all completely beyond me and while the Abstract – written presumably in English – may be perfectly intelligible for an astronomer or a physicist, it is totally incomprehensible for me. But some of the quotations in the accompanying press release – which were picked up and reported widely in the mainstream media (here and here for example) - sounded strangely illogical.

from the Press Release

  • Today the Baryon Oscillation Spectroscopic Survey (BOSS) Collaboration announced that BOSS has measured the scale of the universe to an accuracy of one percent.
  • “One-percent accuracy in the scale of the universe is the most precise such measurement ever made,” says BOSS’s principal investigator, David Schlegel, a member of the Physics Division of the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab). 
  • … the BOSS results suggest that dark energy is a cosmological constant whose strength does not vary in space or time. 
  • …. the BOSS analysis “also provides one of the best-ever determinations of the curvature of space. The answer is, it’s not curved much.”
  • “One of the reasons we care is that a flat universe has implications for whether the universe is infinite,” says Schlegel.
  • … “That means – while we can’t say with certainty that it will never come to an end – it’s likely the universe extends forever in space and will go on forever in time. Our results are consistent with an infinite universe.”
  • … By 380,000 years after the big bang, however, the temperature of the expanding mixture had cooled enough for light to escape, suffusing the newly transparent universe with intense radiation, which in the 13.4 billion years since has continued to cool to today’s faint but pervasive cosmic microwave background.
  • … BOSS collaborator Beth Reid of Berkeley Lab translates the two-dimensional sky coordinates of galaxies, plus their redshifts, into 3-D maps of the density of galaxies in space. “It’s from fluctuations in the density of galaxies in the volume we’re looking at that we extract the BAO standard ruler,” she says.
  • …. The universe’s expansion history has been measured with unprecedented accuracy during the very stretch of ancient time, over six billion years in the past, when expansion had stopped slowing and acceleration began. …

At this point I gave up.

My knowledge of physics and astronomy is sadly lacking and I cannot be reconciled to a universe which is

  • an expanding universe, where
  • the expansion is accelerating, and where
  • the university is infinite, and
  • timeless, and 
  • has been “measured” to an accuracy of 1%

1% of an infinite universe ought to be infinity in my boggled mind!  Is the “ruler” expanding as well? And did time exist before the Big Bang? And if the universe is “timeless”, is time just an artificial construct? And can infinity expand without having a larger infinity?

Oh well! I’m afraid I cannot picture this universe – but I am only an engineer.

Lauren Anderson et al, The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations in the Data Release 10 and 11 galaxy samplesMonthly Notices of the Royal Astronomical Society, 2014.

Abstract: We present a one per cent measurement of the cosmic distance scale from the detections of the baryon acoustic oscillations in the clustering of galaxies from the Baryon Oscillation Spectroscopic Survey (BOSS), which is part of the Sloan Digital Sky Survey III (SDSS-III). Our results come from the Data Release 11 (DR11) sample, containing nearly one million galaxies and covering approximately 8500 square degrees and the redshift range 0.2the baryon acoustic oscillation (BAO) feature. The acoustic features are detected at a significance of over 7σ in both the correlation function and power spectrum. Fitting for the position of the acoustic features measures the distance relative to the sound horizon at the drag epoch, rd, which has a value of rd,fid=149.28Mpc in our fiducial cosmology. We find DV=(1264±25Mpc)(rd/rd,fid) at z=0.32 and DV=(2056±20Mpc)(rd/rd,fid) at z=0.57. At 1.0 per cent, this latter measure is the most precise distance constraint ever obtained from a galaxy survey. Separating the clustering along and transverse to the line-of-sight yields measurements at z=0.57 of DA=(1421±20Mpc)(rd/rd,fid) and H=(96.8±3.4km/s/Mpc)(rd,fid/rd). Our measurements of the distance scale are in good agreement with previous BAO measurements and with the predictions from cosmic microwave background data for a spatially flat cold dark matter model with a cosmological constant.

Cats and physics

January 1, 2014

It’s pretty obvious which kitten is going to grow up to be a physicist.

 

It’s only a matter of time and evolution.

From Luboš Motl’s The Reference Frame

The end of the Universe is nigh and getting closer

December 16, 2013

This is beyond Rapture.

Not just the end of our world, but the end of the entire Universe.

It could happen tomorrow or many billion years later. It may not be the classic Big Crunch which will negate the Big Bang but it could be a phase transition which will cause the entire Universe and all its galaxies and all their suns and all their planets to collapse in on themselves.

Collapse of the universe is closer than ever before

Collapse of the universe is closer than ever before

Journal of High Energy Physics: Standard Model Vacuum Stability and Weyl Consistency Conditions, Authors: Oleg Antipin, Marc Gillioz, Jens Grund, Esben Mølgaard, Francesco Sannino (CP3 – Origins and DIAS). arXiv:1306.3234 arxiv.org/abs/1306.3234

PhysOrgPhysicists have long predicted that the universe may one day collapse, and that everything in it will be compressed to a small hard ball. New calculations from physicists at the University of Southern Denmark now confirm this prediction – and they also conclude that the risk of a collapse is even greater than previously thought.

Sooner or later a radical shift in the forces of the universe will cause every little particle in it to become extremely heavy. Everything – every grain of sand on Earth, every planet in the solar system and every galaxy – will become millions of billions times heavier than it is now, and this will have disastrous consequences: The new weight will squeeze all material into a small, super hot and super heavy ball, and the universe as we know it will cease to exist.

This violent process is called a phase transition and is very similar to what happens when, for example water turns to steam or a magnet heats up and loses its magnetization. The phase transition in the universe will happen if a bubble is created where the Higgs-field associated with the Higgs-particle reaches a different value than the rest of the universe. If this new value results in lower energy and if the bubble is large enough, the bubble will expand at the speed of light in all directions. All elementary particles inside the bubble will reach a mass, that is much heavier than if they were outside the bubble, and thus they will be pulled together and form supermassive centers.

“Many theories and calculations predict such a phase transition– but there have been some uncertainties in the previous calculations. Now we have performed more precise calculations, and we see two things: Yes, the universe will probably collapse, and: A collapse is even more likely than the old calculations predicted”, says Jens Frederik Colding Krog ……. 

The theory of phase transition is not the only theory predicting a collapse of the universe. Also the so-called Big Crunch theory is in play. This theory is based on the Big Bang; the formation of the universe. After the Big Bang all material was ejected into the universe from one small area, and this expansion is still happening. At some point, however, the expansion will stop and all the material will again begin to attract each other and eventually merge into a small area again. This is called the Big Crunch.

“The latest research shows that the universe’s expansion is accelerating, so there is no reason to expect a collapse from cosmological observations. Thus it will probably not be Big Crunch that causes the universe to collapse”, says Jens Frederik Colding Krog.

Although the new calculations predict that a collapse is now more likely than ever before, it is actually also possible, that it will not happen at all ….

Oh Well! No need to stock up anything just yet. No real possibility of some Universal-Engineering to put off the evil day.

I’ll just get more warm clothes for the global cooling that is happening!!

Levitating drops in an ultrasonic field

October 20, 2013

Watch this through!

Absolutely mesmerizing. From the paper “Shape oscillation of a levitated drop in an acoustic field” (arXiv.orgPDF)

via Science is Beauty

Swedish Academician rebuked for talking too much

October 10, 2013

The fuss around the Nobel Prize in Physics  is taking its toll.

Svenska Dagbladet (free translation):

Anders Bárány, Member of the Royal Swedish Academy of Sciences, has been reprimanded for revealing why the announcement of the Physics Prize was an hour late. But Staffan Normark, Permanent Secretary of the Royal Swedish Academy of Sciences Presidium, would not comment. The delay on Tuesday of the announcement of the Nobel Prize in Physics by one hour was unprecedented and quite unique. 

 Mr Anders Bárány had revealed that the delay was caused by heated discussions within the Royal Academy of Sciences (KVA) whether the nuclear research organization CERN would share the prize,His statement had an impact already on Wednesday.

“I was called up to the Academy’s Presidium and given a real scolding” said Anders Bárány.

And I blame the CERN publicity machine for their hype and their blatant lobbying and for causing the controversy in the first place. But Anders Bárány has to take his share of the blame for falling for the publicity machine. He deserved his telling off – not so much for talking to the press after the event but for his support of CERN sharing the award!

What was he thinking?


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