On this day in engineering history, the American astronomer Edwin Hubble discovered the existence of "island universes" beyond Earth's Milky Way galaxy. A man of many talents, Hubble had studied mathematics at Chicago and jurisprudence at Oxford before abandoning a budding legal career to turn
Kozmo: That Doomed Dotcom-Era Internet Delivery Service Had Me At "Hello!" [Y2k10]
When it comes to websites, I've had my share of whirlwind romances. CuteOverload and I had a thing; Scrabulous whispered sweet nothings in my ear for most of 2007. But no site ever captured my attention like Kozmo.
Kozmo and its close relative UrbanFetch were online messenger services that would deliver any number of household products, food items, electronics—almost anything you could imagine. A Kozmo messenger in your area was dispatched the instant you made the order. Delivery was free and tipping was discouraged. Genius! Really, it all seemed to good to be true. This, it seemed, was why the Internet was invented.
The Kozmo guys darted around the city on bikes with orange messenger bags. They each had special Kozmo names like Skip or Spike or Mac. There was something romantic about the notion of these young men (and they were mostly men) dipping in and out of dozens of people's lives each day. It made me feel like I was part of something larger than myself—without actually having to leave my apartment. Each time I went online to order order a video or a bag of pretzels, it was as if I was tugging some imaginary string that would bring a cute guy to my door. A cute guy with presents, no less.
Ultimately, Kozmo broke my heart. It ceased operating in April '01. The memories, however, will live forever: The late-night soup and trashy magazines when I had a cold; the time you brought over Annie Hall and a bag of popcorn at 2AM; the many, many Ben & Jerry deliveries. Kozmo, I would rather have shared one lifetime with you than have to face all the ages of this world alone.
Anna Jane Grossman has joined us for a few weeks, documenting life in the early aughts, and how it differs from today. The author of Obsolete: An Encyclopedia of Once-Common Things Passing Us By (Abrams Image) and the creator of ObsoleteTheBook.com, she has also written for dozens of publications, including the New York Times, Salon.com, the Associated Press, Elle and the Huffington Post, as well as Gizmodo. She has a complicated relationship with technology, but she does have an eponymous website: AnnaJane.net. Follow her on Twitter at @AnnaJane.
New Form of Touchscreen Displays Pioneered, Extremely Multi-Touch [Touchscreen]
You've heard of resistive touchscreens, and hopefully you've been fortunate enough to own a capacitive touchscreen phone. But have you heard of Interpolating Force-Sensitive Resistance, or I.F.S.R touchscreen technology? Touchco hopes you soon will.
A bunch of scientists at New York University's Media Research Lab have grouped together to form Touchco, which is working on the aforementioned I.F.S.R technology. They want to create touchscreens which are even more multi-touch enabled than we've seen so far, capable of receiving simultaneous touch inputs. Apparently these touchscreens can be produced very cheaply, with Touchco hoping to sell them for $10 a square foot.
As you can see from the photo above, these touchscreens are very flexible, and don't require much power—making them ideal for ereaders, laptops and netbooks. [NYT Bits blog]
Vibration Sensor for 3250KVA Genset
Hello,
I have been tasked with locating a Vibration Sensor for this Genset. I is coupled to an EMD 20-654-E4 reciprocating engine. My salesperson found this Metrix ST5484E which should give me the data output I require but I need to order it calibarated and I have no idea what the range wo
Lego Polaroid Camera Can’t Possibly Be More Cute and Lovely [Y2k10]
If this Lego Polaroid 1000 instant camera actually worked, I would buy 24. And then I would destroy them to make a giant camera that takes 24 frames per minute. That would have saved instant photography. [Brickshelf via Obsolete]
Defects in GMAW
What type of Defect occure in GTAW in 6G position (@pipe) manully.
PS3 Controller Fashioned From Nokia N900 [Mods]
The Nokia n900 is not a cool phone, OK? It's just not. But I admit, it can do some cool stuff, like play Duke Nukem 3D and double as a PS3 controller with the help of BlueMaemo. [MaemoCentral via MAKE]
Are humans brighter than the Sun? | Bad Astronomy
You’re the only star in heaven
You’re the only star that shines
You’re the only star in heaven
Now that only star is mine
– Frankie Goes to Hollywood
Snuggler’s lament
These days of northern winter seem endless. It’s been brutally cold here in Boulder, causing much snuggling at night, both between humans and with Canises Major and Minor. Snuggling is fun, of course, but also useful: body heat shared is body heat doubled.
After a while it can get too hot, and even Mrs. BA with her ice cold feet will move away to cool off a bit. When that happens, of course, my mind turns to matters scientific. Our bodies generate a lot of heat. And with the Sun making only a desultory appearance every day, I was thinking recently about the energy generated by the Sun, versus that emitted by humans. I remember reading once that if you compare the heat coming a single square centimeter from the Sun to the same area on a human being, you’d find we actually put out more energy! As a skeptic I’m used to analyzing such claims; as a scientist I have the mad math skillz to work out the numbers; and as a communicator, I have the soapbox upon which I can talk about the whole thing.
So let’s get to it. Are humans more energetic than the Sun?
Yar, thar be math below, and plenty of it. Be ye fairly warned, says I.
Glowing places
As it happens, the math isn’t that hard. Objects that are warm (really, anything warmer than absolute zero) have a characteristic way they emit energy, called black body radiation. Both humans and the Sun are pretty close to being such radiators, and it’s not too bad to just assume they’re blackbodies. There’s a simple equation to calculate the amount of energy emitted per second, called the luminosity:
Luminosity = area of object x σ x temperature4
where σ, the Stefan-Boltzmann constant, is just a number (if you wanna check my math, it’s 5.67 x 10-5 erg cm-2 s-1 K-4, and K is Kelvins, the unit of temperature). That equation makes sense: at a given temperature, a bigger object will emit more energy. And if two objects are the same size, the hotter one will give off more energy (in other words, and to be a bit more vernacular, it’ll be brighter).
The Sun is big, so even if it were colder than a human it would win that fight! So we want to compare apples to apples here, taking one square centimeter of each and seeing who wins. That means we want the luminosity divided by the area, giving us the energy emitted per square centimeter in one second. Rearranging, we get
Luminosity / area = σ x temperature4
Hey, wait a sec! This makes something clear right away: if you want to compare the energy emitted per square centimeter from any two objects, all that matters is their temperatures. The hotter one wins.
That means the story I read — that humans emit more per square cm than the Sun — is wrong. The Sun is a lot hotter than a human, so it emits vastly more energy than a person does! In fact, it’s the ratio of the temperatures raised to the 4th power. The Sun’s temperature is 5780 Kelvins, and a human is 310 Kelvins. Plugging and chugging shows that the Sun gives off a whopping 121,000 times as much energy per square centimeter as a person does!
Yegads. And the Sun is a whole lot bigger. If you’re not careful, you may get the impression the Sun gives off quite a bit of energy.
Pump up the volume
 |
| A cubic Sun. |
Anyway, far be it from me to simply say the story is wrong and drop it. There’s more science here! Instead of using the area, what about the volume? In other words, assume both a human and the Sun have the same temperature throughout (I mean, every chunk of a human is 310K, and the Sun is 5780 K). Would a cubic centimeter of the Sun outshine a cubic centimeter of human?
This is a little bit tougher to calculate. We need the total luminosity of the Sun and its volume, and the same for a human. For the Sun that bit’s actually easy, since we just use that luminosity equation above (knowing the Sun’s area is 6.1 x 1022 square centimeters, which I leave up to you to calculate if you want). The Sun’s energy emitted per second is then about 4 x 1033 ergs/second, where an erg is just a unit of energy astronomers like to use. It’s a small unit, but 4,000,000,000,000,000,000,000,000,000,000,000 of them is still a lot.
What about a human? Well, we need the area of a human to plug into the equation to get the luminosity, and we’ll have to estimate that. Let’s use me as an example, and assume I’m a big rectangular solid, like a shoebox (or a monolith). I’m 177 cm tall, about 50 cm across, and about 15 cm deep. That gives me an area of very roughly 25,000 square centimeters. That’s an estimate, but good enough — it won’t matter if I’m off by a factor of two either way.
Plugging away, I get that my luminosity is then 1.3 x 1010 ergs/sec. That’s a lot smaller than the Sun. But then, I’m not all that hot*.
I am your density
OK, almost there! All we need to do now is divide those numbers by the respective volumes and compare them. The Sun’s volume is 1.4 x 1033 cubic centimeters. That means that each cubic centimeter gives off 4 x 1033 ergs/second / 1.4 x 1033 cc = 2.8 ergs/second/cc. So every second, each cc of the Sun emits 2.8 ergs. OK then. What about me?
 |
| How I know humans and water have the same density. |
My volume is easy to estimate: I know humans are the same density as water, which is 1 gram/cc. I also know my mass is about 75,000 grams, so my volume must be 75,000 cc! Easy peasy.
Finally, dividing my luminosity by my volume yields 170,000 ergs/sec/cc.
Hey, wait a sec! That means not only am I brighter than the Sun, I’m a lot brighter! About 60,000 times brighter!
Make a gas of U and ME
So in that sense, the legend is right. If you want to think of it this way, a cubic centimeter of human gives off a lot more energy than the same volume of the Sun does!
But hold on there. Is this really a fair statement?
Well, not really. First, there are a whole lot more cubic centimeters in the Sun (about 1028 times as many, or ten billion billion billion times as many), so when you divide by such a big number the energy per cc for the Sun drops drastically. So even if we say, sure, humans are more luminous per cubic centimeter, it’s best not to get cocky. The Sun can still vaporize us with lots of cubic centimeters left to spare.
Second, remember the assumption I made, that the Sun has the same temperature everywhere? That’s not even close to being true. In fact, it’s whoppingly untrue. The core of the Sun is 15 million Kelvins hot, so each cc there is blasting out vast amounts of energy: about 5 quadrillion times what a cc of human flesh does. But outside of that region the Sun is much cooler, and each cc doesn’t contribute nearly as much. Over the entire Sun, that dilutes the amount of energy per cc quite a bit. Averaging over the volume of the entire Sun is not a great way to think about it, and makes comparisons difficult, if not really meaningless.
Like this exercise has any profound, deeper truths to it in the first place. Actually, it’s just an excuse to have some fun and do some mental gymnastics. And, in the end, it really comes down to this: the Sun is bright, and we are not.
But, you knew that. Of course, some humans are hotter than others. But I’m not sure I can do the math for that.
Tip o’ the pound of flesh to BABloggee Brad Stacey.
* You can take my word for it, or ask Mrs. BA. She’ll be honest, but her feet lie!
Swimmer image from dionhinchcliffe’s Flickr photostream.
Does This Saab Story Have a Happy Ending?
There's a contingency of Saabisti here at Hemmings, yours truly included, who wear their blue and yellow hearts on their sleeves. Like many of you, we've been watching the safety dance between General Motors and Saab's intended suitors with bated breath. It pains us to think of one of our favo
power electronics
hi im dng my mtech 1styr in power elctronics. i am unable to decide which topic 2 be give for seminar regarding my core field . so kindly request u ppl 2 list out some seminar topics based on power elctronics on ieee.
The Travel Times to Every Spot on the Globe [Infographic]
This map by the European Commission's Joint Research Centre examines the travel times from any spot on the globe to the nearest city of 50,000 or more inhabitants by land or water. The surprise?
As NewScientist observes, less than 10% of the world is more than two days away from a major city using ground-based travel. That stat only jumps to 20% when scaled to the Amazon, where river and expanding road networks have made even jungle terrain semi-assessable.
Also, nobody fucks with the cold climates.
On one hand, the map is a testament to human advancement and expansion. On the other, well, there are a buncha roads in what was once pristine jungle. (Yeah, I saw Avatar twice.) [Flickr and NewScientist via Neatorama]
A Form-fitting Photovoltaic Artificial Retina
From IEEE Spectrum:
Several teams of scientists and engineers have been trying for years to produce a practical retinal prosthesis for people afflicted by a progressive loss of photoreceptor cells. One problem all the researchers face is how to get power and data (the image) to a r
Researchers Demonstrate Nanoscale X-ray Imaging of Bacterial Cells
From ScienceDaily: Latest Science News:
An ultra-high-resolution imaging technique using X-ray diffraction is a step closer to fulfilling its promise as a window on nanometer-scale structures in biological samples. Researchers report progress in applying an approach to "lensless" X
Fora.tv Interview on ClimateGate, Geoengineering, and Copenhagen | The Intersection
While in Copenhagen, I spoke with the folks from Fora.tv for a ten minute interview covering a wide range of topics. These included the dysfunctional way in which our culture processes information about science in general, and about climate science in particular; the continuing stream of misinformation about global warming (particularly the bogus claims that we haven’t had any warming in a decade); the increasing allure of the geoengineering option as progress on emission cuts continues to stall; the reasons for heeding climate models, despite their flaws; and the dangerous possibility that the warming we ultimately see could be on the high end of the current projections.
You can watch it all here, and I have also embedded it below:
Ginkgo biloba – No Effect
Another one bites the dust.
The National Center for Complementary and Alternative Medicine (NCCAM) is generally a waste of taxpayer money, but they have sponsored several well-designed large trials of popular herbal supplements. And one by one these studies have shown these popular products, such as echinacea for the common cold, to be ineffective.
To add to the list, published in JAMA this week are the results of the largest and longest trial to date of Gingko biloba for the improvement of cognitive function and to treat, prevent, or reduce the effects of Alzheimers disease or other dementia. The results of the study are completely negative.
The study was very rigorous – a consensus trial designed to address all the criticisms of prior smaller studies. It was a direct comparison of Gingko biloba at 120mg twice a day, double blind, randomized, multi-center trial involving 3019 subjects aged 72-96 for a median of 6.1 years. Subjects were followed with standardized tests of cognitive function.
The results are easy to report – every measure showed no difference between G biloba and placebo. There was no difference in cognitive function, risk of developing dementia, rate of progression of dementia or normal cognitive decline with aging. Usually such studies involve some random noise in the results, especially when several outcomes are measured. But with such a large study, random fluctuations should average out, and that is exactly what happened.
Gingko biloba has been used for centuries as a medical herb, and the most popular claim made for its use was to enhance cognitive function. The justification for this claim was always thin – G biloba has a mild blood thinning effect. It was therefore claimed that the herbal drug would enhance blood flow to the brain and improve brain function.
However, this is not a plausible mechanism. The brain exquisitely regulates its own bloodflow, and suboptimal perfusion results in a widening of the blood vessels to increase flow. This autoregulation would not be enhanced by mild blood thinning in a healthy individual.
In someone with severe atherosclerosis or narrowing of the arteries, to the point where autoregulation of blood flow is not able to optimize perfusion of brain tissue, the result is typically stroke-like symptoms. In this situation a blood thinner may improve perfusion, and generally drugs like aspirin are prescribed.
This, of course, implies that if simple blood thinning could improve cognitive function, then aspirin would be more effective at this than G biloba. In any case, this putative mechanism was never very plausible.
More recent studies have found that G biloba has some anti-oxidant effects. However, anti-oxidants as a class have not been found to be effective for cognitive function or any other clinical outcome. So this too lacks plausibility.
It was also found that G biloba can reduce amyloid aggregation. Amyloid plaques build up in the neurons of patients with Alzheimers disease, so this is a plausible mechanism for slowing the progression of some forms of dementia. However, as we now know this does not translate into a measurable clinical effect.
The lessons from this study and the lack of effect for Ginkgo biloba should learned and generalized.
Historical use of an herbal drug is not sufficient evidence for its effectiveness.
Preliminary, small, or poorly designed studies are unreliable, and often result in false positives. Only large definitive trials are reliable.
Finding a potential mechanism for a drug, herbal or otherwise, is not a sufficient basis for a clinical claim – you need clinical trials with actual people to support such claims. Further, if researchers go looking for potential mechanisms to explain a putative action of a drug or supplement, it is not surprising that they will find some. Drugs typically have many biochemical actions in the body, and finding an effect is not surprising. There is also likely confirmation bias and the file-drawer effect at work – favoring the publishing of interesting and positive studies.
In the end – all the ancient wisdom, small studies, and putative mechanisms meant nothing. They were all trumped by a large and impeccably designed study that shows Gingko biloba is of no measurable benefit for cognitive function.
These results call into question the practice in many countries of allowing pharmacological agents like G biloba to be marketed as supplements with health claims prior to being adequately studied. The European and US markets for G biloba are in the hundreds of millions of dollars per year. It will be interesting to see what happens following this study.
The study did find that G biloba was generally safe. However, it should be noted that G biloba, although sold in the US as a supplement, should be considered a drug. It does have an anti-platelet blood-thinning effect and should not be taken prior to surgery. However, because many people think of herbs as supplements and not drugs, patients rarely disclose their supplements to their doctors, and doctors fail to take a supplement history. Safety is therefore still an issue.
Herbs and botanicals have been and can be a valuable source for useful pharmacological agents. However, regulating and using them as supplements has many flaws – as the history of Gingko biloba once again highlights.
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Sidecar Made From WWII German Fighter Plane and Yamaha Motorbike Is Crazy-Cool [Transport]
Made from a WWII German fighter plane and Yamaha Wild Star motorbike, this sidecar bike looks like a less-colorful Chitty Chitty Bang Bang. [Henrik Toth via LikeCool]
Light-Emitting Wallpaper Using OLED Technology Could Light Our Homes By 2012 [Oled]
Traditionally favored by middle-aged women, wallpaper could cut carbon emissions and eliminate the need for light bulbs, with a UK company using OLED technology to create light-emitting wallpaper.
The government-backed Carbon Trust has awarded a £454,000 ($720,000) grant to a company by the name of Lomox, to develop the special wallpaper. Inspired by OLED TVs which use low voltage, Lomox hopes to use some of the same technology for wallpaper that lights up rooms and outdoor areas, believing they can get an affordable product to market by 2012.
Let's just hope they don't stop at Laura Ashley for design influence. [FT]
Image Credit: Country Living
Surge analysis
Surge Analysis is advisable for Gas line ? or only for liquid line.
Android 2.1 Ported To G1, Official OTA Download Coming Soon? [Android]
The last time we heard about the antiqued G1 being loaded with 2.1 it turned out to be fake, so we're not holding our breath now. Nonetheless, AndroidSpin user Drizzy is claiming success, with the ROM on its way.
Speculation is also pointing at an official over-the-air 2.0 or 2.1 upgrade for the G1, but considering the G1 is over a year old now and not exactly Google's priority these days, don't go holding out for an official one just yet. [AndroidSpin via RedmondPie]
Brake System Proportioning Valve
I am still redoing the brake system on 1948 ford F1, on the rear axel there is a small brass block that the rear brake lines and the main from the master cyl. tie into, I tried to remove it to clean or replace it and found a swivel cap on top of the unit, my question is as follows; is this a balanci