Author Archives: curiouscat

High-efficiency Power Supplies

High-efficiency power supplies for home computers and servers (pdf) by Urs Hoelzle and Bill Weihl – Google:

Most likely, the computer you’re using wastes 30-40% of the electrical power it consumes because it is using an inefficient power supply. It’s difficult to believe that something as basic as a power supply could be responsible for that amount of waste, but it’s true.
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The opportunity for savings is immense — we estimate that if deployed in 100 million PCs running for an average of eight hours per day, this new standard would save 40 billion kilowatt-hours over three years, or more than $5 billion at California’s energy rates.
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The net result of these changes is a dramatic improvement in efficiency (including the power supply and the regulators) to about 85%, at virtually no cost. In other words, you won’t have to pay more for a higher-efficiency PC, because the power supply is actually getting simpler, not more complicated. By spending another $20 or so extra, it is possible to use higher-quality components and achieve efficiencies well over 90%.

Remote-Controlled Submarines

Remote-Controlled Omnidirectional Submarines:

These remote-controlled submarines fit into the palm of your hand and have dual propeller propulsion systems that allow omnidirectional movement underwater in a bathtub, swimming pool, or in shallow ponds. The submarines dive and surface like an actual naval submarine, and the three high-powered motors ensure rapid movement forward, backward, left, right, and while performing 360 progressive rolls. The submarines have dual LED headlights and each unit operates on a unique radio frequency, allowing underwater races with multiple submarines. Includes rechargeable batteries that run for three minutes after a three minute charge.

Fun looking toy. Via: Remote-Controlled Submarines. Related: Science and Engineering Gadgets and Gifts – Lego Autopilot Project Update – Underwater Robots Collaborate

Water Buffaloes, Lions and Crocodiles Oh My

Pretty amazing video. A look at real wild life with lots of excitement, a bit violence and some surprising turns. On my trip to Kenya I saw an interaction between lions and one water buffalo but it was without much of this action. Basically there was a standoff for like half an hour with half charges and the like. Even that was very interesting.

Building Engineering Outside the Box

Helix — a 1D skyscraper with a single corridor:

The principle is a cylindrical building with a helical shape for the floor. The slope of the floor is 1.5% (it rises by 1.5 cm every meter), thus hardly noticeable. The height of each ’storey’ is 3 meters, so that when you walk 200 meters along the corridor, you have walked a full circle, but you end up one ’storey’ above or below your starting point. This results in a diameter of approximately 60 meters, therefore quite common for large skyscrapers. The corridor is on the outside, so that everybody has access to the fabulous views over the city. Offices are all on the inside. As the tower is hollow in the middle, and the inner diameter of the patio is still approximately 40 meters, this makes for a very nice light shaft with peaceful lighting conditions.

The floor of each office is made horizontal, so that your chair does not roll down and hit the separation. But if you take your chair in the corridor, be careful not to let go of it. All things rolling naturally find their way to the lost+found in the lobby.

Ok, this doesn’t seem really practical for a skyscaper but it still is a cool thought experiment. And as they mention it works fine for the Guggenheim Museum in NYC.

Chemistry of Common Items

The American Chemistry Society offers interesting articles on the chemistry of everyday products including: amber, henna, catnip and honey:

To make this delicious treat, foraging bees start out by guzzling nectar, a dilute solution of sugars in flowers. Then, they mix the nectar with enzymes in their stomachlike honey sacs. Back at the hive, the foragers pass the digested material to house bees who reduce the moisture content of the mixture by ingesting and regurgitating it. They then deposit concentrated drops into honeycomb cells. Over the next few days, bees fan the fluid with their wings to further concentrate it, and finally, they cap the cells with wax. At the same time, enzyme-mediated changes produce a range of sugars and acids in the honey.

Bee enzymes also show up in the finished product. Invertase is the most critical. It splits the sucrose in the nectar into fructose and glucose and also produces some erlose. Another enzyme, glucose oxidase, converts glucose to gluconolactone, which is then hydrolyzed to give gluconic acid, the principal acid in honey. Formic, acetic, butyric, and lactic acids are also found in honey, which explains why its pH typically measures 3.8-4.0 and bacteria have a hard time growing in it.

Engineering, Math and Physics Applets

Java applets illustrating concepts in math, physics and engineering including: Coupled Oscillations, Digital Filters, 3-D Magnetostatic Fields and Ordinary Differential Equations.

CERN Prepares for LHC Operations

A Giant Takes On Physics’ Biggest Questions

The physicists, wearing hardhats, kneepads and safety harnesses, are scrambling like Spiderman over this assembly, appropriately named Atlas, ducking under waterfalls of cables and tubes and crawling into hidden room-size cavities stuffed with electronics.

They are getting ready to see the universe born again. Again and again and again – 30 million times a second, in fact.

Starting sometime next summer if all goes to plan, subatomic particles will begin shooting around a 17-mile underground ring stretching from the European Center for Nuclear Research, or CERN, near Geneva, into France and back again – luckily without having to submit to customs inspections.

Crashing together in the bowels of Atlas and similar contraptions spaced around the ring, the particles will produce tiny fireballs of primordial energy, recreating conditions that last prevailed when the universe was less than a trillionth of a second old.

Wow that sounds impressive. Oh yeah, it is impressive. Good writing too.

Bird Species Plummeted After West Nile

Bird Species Plummeted After West Nile:

Several common species of North American birds have suffered drastic population declines since the arrival of the West Nile virus eight years ago, leaving rural and suburban areas quieter than they used to be and imposing ecological stresses on a variety of other animals and plants, a new study has found.

In Maryland, for example, 2005 chickadee populations were 68 percent lower than would have been expected had West Nile not arrived, and in Virginia chickadee populations were 50 percent below that prediction.
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It shows that the post-1998 declines were greatest at times and places in which the virus was especially prevalent — as indicated by the number of human infections diagnosed. As expected, American crows were among the worst hit, suffering declines of as much as 45 percent in some regions and wipeouts of 100 percent in some smaller areas. Other species that suffered included the blue jay, the tufted titmouse, the American robin, the house wren, the chickadee and — unexpectedly — the American bluebird.

Hot Ice Planet

Scooped!:

The planet has a mass of 23 Earth-masses and an orbital period of 2.64385 days. It orbits a red dwarf star 33 light years away. The temperature on the planet is somewhere in the oven-cleaning neighborhood of 600K (327K, 620F). No habitability news stories on CNN for this fine fellow. The transit depth is a healthy 0.6%, which implies that the the planet’s radius is ~25,000 km. That’s four times that of the Earth, and essentially identical to the 24,764 km radius of Neptune.

Astronomers Detect Shadow Of Water World In Front Of Nearby Star:

As the planet is close to its host star, its surface temperature is expected to be at least 300 C (600 F). The water in its atmosphere would therefore be in the form of steam. Inside, the water is crushed under intense pressure and adopts states unknown on Earth, except in physicist’s laboratories. Says FrÃ©dÃ©ric Pont: “water has more than a dozen solid states, only one of which is our familiar ice. Under very high pressure, water turns into other solid states denser than both ice and liquid water, just as carbon transforms into diamond under extreme pressures. Physicists call these exotic forms of water ‘Ice VII’ and ‘Ice X’. If Earth’s oceans were much deeper, there would be such exotic forms of solid water at the bottom.” Inside GJ 436’s planet, this strange ice is moreover heated to many hundred degrees.

Proof – Movie

It is a stretch to say this post is related to math but the plot of the movie involves a mathematical proof so… I just watched the Proof DVD and thought is was excellent, and I get to write about what I want, and therefore this post exists. It really is a great movie but doesn’t have much at all to do with math other than as a backdrop.

The main mathematician characters flirt with (or have) mental illness – which seems to be a common combination in movies: Pi, A Beautiful Mind and Good Will Hunting (all worth watching by the way).