Friday, July 25, 2014
The amazing dual behaviour of hydrogen.
HYDROGEN COMPOUNDS
Hydrogen in atomic form consist of one proton and one electron but , in elemental form it exists as a atomic ( H2 ) molecule . H2 is called as dihydrogen.
Position of hydrogen in the periodic table : Hydrogen is the first element of the periodic table as its atomic number is 1 . The single electron is present in the K shell i.e 1s1
The real growth in Neuroscience
Neuroscience is advancing rapidly. Nobody's questioning that. Brain-computer interfaces, optogenetics, transcranial magnetic stimulation—there's a lot of good stuff out there.
With respect to applications, a gaggle of neurotechnology startups are already starting to chip away at some curious corners of the medical technology space. But is the market ready? And more importantl y, is the science ready? This piece gives us some relatively concrete projection s on market readiness and financial/ scientific feasibility for a handful of emerging technologi es .
I'm a bit more conservat ive than the authors, though. Mainstrea m optogene tic implants in humans by 2026? Even if neuroscie nce does manage to wrangle $4.5 billion in extra funding over the next twelve years, I don't see this happenin g.
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Optogenetic implants in humans: The combination of genetic and optical methods to control specific events in targeted cells of living tissue, even within freely moving mammals and other animals, with the temporal precision (millisecond timescale) needed to keep pace with functioning intact biological systems.
Scientifically viable in 2021; mainstream and financially viable in 2026.
Really very hot stuff : Pepper
You know that tingling, numbing sensation you get from Sichuan peppers? It turns out that 'tingling' and 'numbing' might actually be the best way to describe it. A series of recent studies has shown that the relevant ingredient in the peppers targets neurons that respond to touch and vibration, thereby triggering the buzzing perception.
What's more is that evidence suggests we all feel those tingling vibrations at the same frequency. (It's around a low G.)
If only science was always this spicy.
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The task for the tingling volunteers was to try to match the peppery vibrations in their mouths to the vibrations they could feel in their fingertips as the researchers dialed the frequency of the box up or down — "They are closing their eyes and they're saying 'higher' or 'lower,' so it's kind of a bizarre situation," says Hagura — until the Sichuan buzz and the mechanical buzz converged on the same frequency, which turns out to be 50 hertz.Thursday, July 24, 2014
NASA X-43A 'Scramjet' Readied For Mach 10 Flight
NASA's high-risk, high-payoff Hyper-X Program is ready to attempt its greatest challenge yet - flying a "scramjet"-powered X-43A research vehicle at nearly 10 times the speed of sound.
Officials have set Nov. 15 or 16 for the flight, which will take place in restricted U.S. Naval airspace over the Pacific Ocean northwest of Los Angeles.
GaneshScience: s-BLOCK ELEMENTS
GaneshScience: s-BLOCK ELEMENTS: custom toolbar custom toolbar S.No. Atomic Properties Alkali metal 1. Outer electronic configuration ns^1 2. Oxidation nu...
Anti-Evolutionist s Need to Stop Talking About thermodynamics
The anti-evolutionists just never get tired of the second law thermodynamics! The latest bit of silliness comes from Barry Arrington, writing at Uncommon Descent. Here’s the whole post:
I hope our materialist friends will help us with this one.
As I understand their argument, entropy is not an obstacle to blind watchmaker evolution, because entropy applies absolutely only in a “closed system,” and the earth is not a closed system because it receives electromagnetic radiation from space.
Fair enough. But it seems to me that under that definition of “closed system” only the universe as a whole is a closed system, because every particular place in the universe receives energy of some kind from some other place. And if that is so, it seems the materialists have painted themselves into a corner in which they must, to remain logically consistent, assert that entropy applies everywhere but no place in particular, which is absurd.
Now this seems like an obvious objection, and if it were valid the “closed system/open system” argument would have never gained any traction to begin with. So I hope someone will clue me in as to what I am missing.
I think Arrington is missing quite a lot, actually.
Let’s start with the obvious. Many physical laws and theories only strictly apply to idealized scenarios, but that does not stop them from being very useful. There are no ideal gases in nature, but we have an ideal gas law that tells us how they behave. Physical objects never engage in perfectly elastic collisions, but classical mechanics tells us quite a lot about what would happen if they did. Heck, there are no triangles in nature, but trigonometry is still fantastically useful stuff.
So, yes, the only truly closed system is the universe as a whole, a fact pointed out in virtually every book on thermodynamics. But there are many systems that are close enough to closed for practical purposes, and that is enough to make the second law very useful indeed.
(Incidentally, for the purposes of this post I won’t belabor the distinction between a closed system and an isolated system. The former refers to one where no mass is crossing the system’s boundary, while the latter requires that neither matter nor energy is crossing the boundary. If you are making the statement, “Entropy cannot spontaneously decrease,” then you had better be talking about an isolated system. While we’re at it, for the purposes of this post I will be discussing everything in the context of classical thermodynamics. I will not discuss statistical mechanics or anything like that.)
The bigger thing that Arrington is missing, however, is that there is so much more to the second law than the statement that entropy cannot decrease in an isolated system.
One frustration in learning about thermodynamics is that you can consult a multitude of textbooks and popularizations and never find the second law stated the same way twice. Sometimes it is boiled down to the simple statement that heat always travels from a hot body to a cooler body. Sometimes it is expressed in terms of heat engines. Sometimes it is presented with an impenetrable amount of mathematics. Making things worse is that it is very hard to pin down what, precisely, entropy is. That’s why you get a lot of talk about complexity, or randomness, or useful energy, in popularizations of this topic. These ideas capture some of the spirit of the concept, but they also fool a lot of people into thinking they know what they are talking about.
When creationists first noticed that the second law could be used to rhetorical advantage, they tended to do so in a shockingly naïve way. For example, here’s Henry Morris, from his bookThe Troubled Waters of Evolution:
Evolutionists have fostered the strange belief that everything is involved in a process of progress, from chaotic particles billions of years ago all the way up to complex people today. The fact is, the most certain laws of science state that the real processes of nature do not make things go uphill, but downhill. Evolution is impossible!
And later:
There is … firm evidence that evolution never could take place.The law of increasing entropyis an impenetrable barrier which no evolutionary mechanism yet suggested has ever been able to overcome. Evolution and entropy are opposing and mutually exclusive concepts. If the entropy principle is really a universal law, then evolution must be impossible.
Now, when creationists are saying things likethat, it is perfectly reasonable to emphasize in reply that the second law only precludes spontaneous decreases in entropy in isolated systems, which the Earth certainly is not. But that statement is hardly the entirety of what physicists know about entropy.
To fully understand the magnitude of what Arrington is missing, we should consider what the second law was accomplishes. The principles of thermodynamics make certain claims about what sorts of processes are physically possible.
Super-sniffing elephants
Super-sniffing elephants
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