“Will you take a lead, not just to talk about it, not just to opine about it, but actually do the things necessary to see if we can’t restart our nuclear industry?” asked Senator Jeff Sessions of Alabama. Tennessee Senator Bob Corker echoed the question later, asking Chu if he meant to “pursue nuclear now… all out now?”
Yes, yes, and yes, Chu replied. “Nuclear power is going to be an important part of our energy mix,” he told the committee, a position he has stated before. Chu noted that nuclear power provides 70% of the carbon-free electricity in the country. Still, he said it was important to continue researching better waste disposal and fuel recycling technologies, perhaps in collaboration with other countries.
Objects exhibit quantum behavior when squeezed into a tight space. A new experiment has clearly demonstrated the wave-like properties of a hydrogen molecule inside a tiny carbon cage. Using neutrons to probe the state of the molecular prisoner, the researchers showed quantized states in both rotation and linear motion of the molecule, much like the “ladder” of excited electron states in an atom.
Tilt-Shift photos are the ones that look like they are of a miniature scene, but are really a trick of the focus and depth-of-field. You can do it with a special lens, or with software. Which is now available online: Tilt Shift Maker
If confirmed as expected, Chu may well set sparks flying at the staid agency. Over the past four years, Chu has realigned the DoE’s Lawrence Berkeley National Laboratory (LBNL) in California into a pioneer for alternative-energy research.
Using an ice-hockey analogy, Eddy Rubin, director both of the Joint Genome Institute in Walnut Creek, California, and of the genomics division at the LBNL, says: “You can’t stay where the puck is — you have to skate where the puck is going to be. [Chu] had a compelling vision to put the lab where it needs to be.”
And I wonder who the Goons are going to be, to do the necessary forechecking?
According to the division directors, Chu said he would take the job if he could select the approximately 15 political appointees who would direct key DoE components. In the early days of the Bush administration, vice-president Dick Cheney was behind most of those appointments. Instead, “Chu will get to select the smartest people he knows”, says Rubin.
Unlike some other types of animals, humans generally don’t perceive polarization of light, or rather we do so very weakly so it’s not something we normally notice. The link explains how to check for it and what to look for.
The eyes of men (AND women) are not designed to distinguish between different types of polarization, contrary to insects, cephalopods, many amphibians, fish, and other animals, for which nature possesses a different class of “colors” (but even common colors do not mean the same to everyone). However, a small quirk in the structure of the human eye gives us (by accident) the ability to tell apart different states of polarization. Thanks to this small aberration or “defect” of the eye we are not completely polarization-blind.
Yes !!! With some effort you can learn to see what remains invisible to most people! Without the help of any instrument you will be able to tell not only if the light you look at is strongly polarized or not, but also if it is linearly polarized or circularly polarized and, moreover, in which direction it vibrates or rotates. Any time that you raise your eyes to the blue sky you will be rewarded by the same clues that guide bees in their flight. Acquire P-Ray Vision !
I tried it with my LCD monitor (which, as we know, is polarized) with both a white and blue background, the latter for contrast to show the yellow. I think I see the yellow brush, but it’s not very distinct. I’ll keep trying, but I don’t think this is like those 3-D drawings that jump out at you all of the sudden.
While I was on vacation I had seen a couple of videos/links about a guy who launched himself with some water rocket of the large soda-bottle variety, and thought that this was the sort of thing Rhett would analyze over at Dot Physics, and as I catch up with my blog reading, I see that it is so: Water Bottle Rocket Guy
“Water bottle rocket guy” is too impersonal and too long to type repeatedly, so I will refer to him as “Mr. Payload”
The thing that screams, “Fake!” the loudest is the video snippet that indicates a cable attached to Mr. Payload’s harness. I notice that he also starts tumbling, as one might expect from a torque from the rockets, but this motion does not continue — something that a guide cable would interrupt. There’s also the trajectory analysis, which doesn’t jibe with expectations.
Rhett does a quick energy analysis of the maximum height, but the analysis assumes all of the energy goes into Mr. Payload and his rocket shell, thus giving an absolute maximum height, and the number he gets isn’t realistic. One must also consider the large amount of energy contained in the expelled water that generates the thrust to get a more realistic limit, as well as the energy used for the forward motion.
Rhett uses 1L of water per bottle , but to me it looks like there is more. I’m going to assume 20L of water but the same energy (i.e. higher pressure) and that Mr. Payload has a mass of 60 kg, which is more than Rhett uses but makes the math easy. Since the water is expelled quickly — it appears to be gone before he’s more than 2m above the dock, so I’m just going to model this as an explosion, with the water getting an impulse and Mr. Payload getting an equal and opposite impulse. Their kinetic energies must add to the total energy of the system, of 27kJ.
We have the sum of the KEs totaling 27 kJ, with \(KE = p^2/2m \) and equal magnitudes of momentum.
Solve for momentum, and I get 900 kg-m/s, or a speed of 15 m/s for Mr. Payload. If launched at ~30º, as in the video, that’s a height of under 3 meters, ignoring the considerable drag. It also means that about 20 kJ of the available energy (i.e. 3/4 of it) went into the expelled water.
One of the comments links to a video which looks real. The launch is at about 3:15
Of all the animals in the world, the lowly spookfish has the oddest eyes — compound mechanisms that bear more than a passing resemblance to rearview mirrors.
The bottom half of its eyes point upwards. The upper half point downwards, and are backed with a layer of reflective guanine crystals that bounce a focused image into the retina.
The titular disclaimer comes from reading this:
Researchers tested the eyes by taking flash photographs from above and below a live spookfish, then dissecting its eyes.
Researchers from Loyola University Health System and other centers compared African American women in metropolitan Chicago with women in rural Nigeria. On average, the Chicago women weighed 184 pounds and the Nigerian women weighed 127 pounds.
Researchers had expected to find that the slimmer Nigerian women would be more physically active. To their surprise, they found no significant difference between the two groups in the amount of calories burned during physical activity.
“Decreased physical activity may not be the primary driver of the obesity epidemic,” said Loyola nutritionist Amy Luke, a member of the study team.
While it may be true that diet, not exercise, causes the obesity, it’s fallacious to conclude that exercise won’t make any difference. It just isn’t a factor in this example. You have two variables that affect weight (Calories in and Calories burned), and only see that one is different here. At the very basic level, it’s conservation of energy.
People burn more calories when they exercise. Thing is, they compensate by eating more, said Richard Cooper, co-author of the study and chairman of the Department of Preventive Medicine and Epidemiology.
“We would love to say that physical activity has a positive effect on weight control, but that does not appear to be the case,” Cooper said.
It’s not clear if this was tested in the study — there’s no mention in the story — so one doesn’t know if it was a crappy experiment or it’s crappy reporting.
