Showing posts with label science. Show all posts
Showing posts with label science. Show all posts

Saturday, 11 November 2017

What is it about electricity that makes it so dangerous to the human body?

Your body uses electrical signals in its nerves.The major way people die from electric shocks is if it goes through the heart. Your heart is a finely tuned machine that does not appreciate a sudden external signal saying contract all muscles. If you're lucky, your heart resumes beating with its normal pattern. If not, hope someone around knows CPR.

Incidentally, this is also a bugbear for medical shows - the device with the paddles and the shouting clear doesn't restart the heart, it stops the heart and is used when the rhythm has gone wrong (called fibrillation). The heart can then restart itself with the correct rhythm (hopefully).

AC is more dangerous than DC.The fluctuation rate of 60 Hz makes the currents particularly suited to screwing up the nerves that regulate heartbeat. This can cause a heart to flutter instead of beating normally, which kills a person quickly. That's why standard AC wall current is especially dangerous to humans. The threat of AC current varies widely by its frequency, whereas DC simply becomes more dangerous as the voltage and current levels increase.

Source Reddit
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Thursday, 4 February 2016

Stephen Hawking's new theory on black holes : Simply Explained

While I can't speak to the specifics, as a layman who has followed this since reading "a brief history of time" I can say that it's a pretty big deal if he's right.
Basically, black holes have been considered to "destroy information" which basically means you can't see what's inside a black hole. This is a big problem in physics because energy/matter/information can't be "destroyed."

What Hawking is saying now is that the information isn't destroyed, but instead sort of "imprinted" on the event horizon of a black hole.

An event horizon is what we might consider the border of inside vs outside the black hole. Everything past that line is "inside" the black hole and can't be seen because even light gets trapped in it. But if an object or particle enters a stable orbit on that boundary, special things happen that I don't understand and can't really describe.

However, I can say that what Hawking is saying is that if something crosses this barrier, it effects how the event horizon looks, and therefore in a way, we can retrieve that information, kind of like looking at footprints in the snow leading up to the edge of a cliff.
I may be way off base here, but that's my understanding and I invite anyone with a better understanding to ELI5 to me.
Edit: there is no stable orbit on the event horizon.
All right, let's say you have a friend named Simon, who's a normal weight and loves junk food, and a friend named Albert, who's extremely fat and also loves junk food. Since you're buddies with Simon, you'd be able to guess what junk food they're gonna eat next based on what they ate before and you'd also be able to guess what they had eaten based on the wrappers and boxes left over. However, even though you're buddies with Fat Albert, he's just so huge that when he gets near enough something to eat, he swallows it wrapper and all. You have no idea what he'd eat next or what he ate before because he swallowed anything and everything near him. BUT NOW, all of a sudden, you realize that Albert is not only fat, but he's a messy eater. Because of this, you realize that there are crumbs, smudges, and pieces of the food left around his mouth. So you're like, OH! Now I know what you ate. Maybe in time you could use that to learn his eating habits just like you know your buddy Simon's!
So in this case, you're Mr Hawking, and you realized that the black hole, Albert, although he seemed not to leave evidence of food (information), actually might leave that evidence at the edge of his mouth (the event horizon = the edge of the black hole). You can use that to figure out all sorts of things!
(Hopefully this helps people, this is my first post here!)

Edit: Wow, I was just writing this as a joke, I didn't expect so many people to like it! Thanks so much for the gold and for everyone who enjoyed it! For the people who are asking if I'm a teacher, I'm not, I'm just a young adult applying to med school haha. Thanks again!

For people who are still a little confused by what the theory is, and why I talked about Simon: The original thing that we thought was what I described at the beginning, that for any normal scenario (a Simon) we would be able to get information, but in the case of a black hole (Albert), we can't. But Hawking's theory is your theory that if you look at the edge of his mouth, you can see the crumbs and figure out a pattern to how he's eating just like you did with a normal case like Simon. In the same way, looking at the event horizon (the "edge" of a black hole) might let you get the information that we before thought was destroyed. Hope that makes sense!





Source ELI5 REDDIT.COM
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Monday, 6 April 2015

Liquid body armor tested in Poland

Scientists at a Polish company that produce body armor systems are working to implement a non-Newtonian liquid in their products.

The liquid is called Shear-Thickening Fluid (STF). STF does not conform to the model of Newtonian liquids, such as water, in which the force required to move the fluid faster must increase exponentially, and its resistance to flow changes according to temperature. Instead STF hardens upon impact at any temperature, providing protection from penetration by high-speed projectiles and additionally dispersing energy over a larger area.

"This viscosity increases thanks to the subordination of the particles in the liquid structure, therefore they form a barrier against an external penetrating factor," said Karolina Olszewska, who performed tests on the STF for Moratex.

The exact composition of the STF is known only to Moratex and its inventors at the Military Institute of Armament Technology in Warsaw, but ballistic tests proved its resistance to a wide range of projectiles.

"We needed to find, design a liquid that functions both with projectiles hitting at the velocity of 450 meters per second and higher. We have succeeded," said Deputy Director for Research at the Moratex institute, Marcin Struszczyk.

Struszczyk said the liquid's stopping capability, combined with the lower indentation of its surface, provides a higher safety level for the user compared with traditional, mostly Kevlar-based, solutions.

"If a protective vest is fitted to the body, then a four centimeter deep deflection may cause injury to the sternum, sternum fracture, myocardial infarction, lethal damage to the spleen," Struszczyk said.

"Thanks to the properties of the liquid, thanks to the proper formation of the insert, we eliminate one hundred percent of this threat because we have reduced the deflection from four centimeters to one centimeter."

When hit by a high-speed projectile, a wide area of the STF hardens instantly, causing the usually massive energy to be dispersed away from the wearer's internal organs.

Implementing the solution in body armor required designing special inserts, but the company says those are lighter than standard ballistic inserts and broader range of movement for their users in the police and military.

"The point is for them not to interfere, not change the way of movement, operation of such the product by the user, and at the same time increase their motor skills, increase effectiveness of their decision process and increase their possibilities during the mission at hand," Struszczyk said.

The laboratory is also working on a magnetorheological fluid, which they hope can be also applied in their products.

According to the researchers, both liquids can find applications beyond body armor, such as in the production of professional sports inserts, and even entire outfits. Another use could be in car bumpers or road protective barriers.

Source Reuters
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Tuesday, 27 January 2015

Greenland ice may melt faster due to increase in temperature

A new study has shed light on Greenland Ice demonstrating that the more temperatures increase, the faster the ice will melt.
The model experiments conducted by Penn State geoscientists suggested that if all the ice in the Greenland Ice Sheet melts, global sea level would rise by about 24 feet.
Patrick Applegate, research associate, Penn State's Earth and Environmental Systems Institute, said that although lots of people have thought about sea level rise from the ice sheets, they don't really know how fast that will happen.
Greenland might be especially vulnerable to melting because that area of the Earth sees about 50 percent more warming than the global average. Arctic sea ice, when it exists, reflects the sun's energy back through the atmosphere, but when the sea ice melts and there is open water, the water absorbs the sun's energy and re-radiates it back into the air as heat. Arctic sea ice coverage has decreased over the last few decades, and that decrease will probably continue in the future, leading to accelerated temperature rise over Greenland. Floating ice does not add to sea level, but the Greenland Ice Sheet rests on bedrock that is above sea level.
The researchers looked at two models of the Greenland ice sheet that include some of the important feedback. The first model is a three-dimensional ice sheet model. The second model looks at a transect across the island and was developed by Byron Parizek, associate professor of geosciences and mathematics, Penn State Dubois. To run both models, Robert Nicholas, research associate, EESI, estimated how much warming might take place over Greenland using results from global climate models.
Both the three-dimensional and transect models showed that the time necessary for ice mass loss from the Greenland ice sheet decreases steeply with increases in temperature. Shorter time scales-faster melting-imply faster sea level rise. The interplay between the height-melting feedback and ice flow causes this acceleration.
The researchers said that their analysis suggests that the benefits of reducing greenhouse gas emissions, in terms of avoided sea level rise from the Greenland Ice Sheet, may be greatest if emissions reductions begin before large temperature increases have been realized.
The study is published in the journal of Climate Dynamics.
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Friday, 20 June 2014

Albino whale spotted off Australia coast

A rare albino whale has been sighted off the coast of Australia on Tuesday.
The albino humpback, nicknamed "Migaloo", was first spotted in 1991 and sibce then researchers have tracked his movements.

The sighting was confirmed by White Whale Research Center Oskar Peterson, reporters have said, adding, the footage of the sea creature has been caught on a mobile phone's camera along the Green Cape in New South Wales.
Peterson told ABC News Australia, "He's quite an amazing sight."
In 2011, whale watchers discovered another all-white humpback and nicknamed him Migaloo Junior.
According to Peterson, the mammal glows in the water like a fluorescent bulb. According to International Business Times, Migaloo Junior does not appear before spectators every year, but Migaloo appears during the annual migration from the Antarctic to the site of breeding along the Great Barrier Reef.
Pictures and videos of Migaloo sighting have been shared on micro-blogging sites.
According to experts, male humpbacks can travel around 140 kilometers a day. Humpback whales are known to survive for as long as 90 years.

 

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Monday, 16 June 2014

Scientists discover massive ocean of water 400 miles underground

Researchers at Northwestern University have found evidence for a massive reservoir of water deep within the Earth's mantle. The reservoir, which is said to be three times the volume of the oceans on the surface, is contained within highly-pressurized rock known as ringwoodite. The scientists hope that their findings, recently published in the journal Science, can shed light on where Earth's oceans came from. "Three times the volume of the oceans on Earth's surface" The team, led by mineralogist Steven Jacobsen, used an array of 2000 seismometers to study how seismic waves generated by earthquakes move through the Earth's interior. The waves' speed changed depending on the type of rock they pass through, and wet ringwoodite has a particular effect on wave velocity. Jacobsen was able to reproduce wet ringwoodite in his lab, and the group's findings matched what he observed in the lab. As it turns out, ringwoodite, under the extreme heat and pressure of the mantle, bleeds water. That water would then become trapped in the transition zone at between roughly 200 and 400 miles underground. The new research lends credence to theories that our oceans originated on Earth. However, more tests will need to be conducted moving forward. Jacobsen's team could only verify that the reservoir exists below the continental United States, so it's unclear how far this "ocean" extends.

Source The Verge
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Friday, 9 May 2014

14 new species of dancing frogs discovered in Western Ghats

Indian scientists have discovered new 14 species of dancing frogs in the world’s waning ecological hotspot — the Western Ghats.

The dancing name is courtesy the males, who employ unusual kicks to attract mates. This is a unique breeding behaviour called foot-flagging.

The males stretch, extend and whip their legs out to the side to draw the attention of females. Such displays come in handy because there is a possibility of mating croaks being drowned out by the sound of water flowing through perennial hill streams.

The bigger the frog, the more vigorous the dance. “They need to perform and prove, ‘Hey, I’m the best man for you,’” said SD Biju, a botanist-turned-herpetologist now celebrated as India’s “Frogman” for discovering dozens of new species in his four-decade career.
Watch: Scientists discover 14 new species of dancing frogs in western ghats


A study listing the new species was published on Thursday in the Ceylon Journal of Science. It brings the number of known Indian dancing frog species to 24.

The tiny amphibians of the genus Micrixalus trace their origin to 85 million years ago. Their habitat is drying because of excessive development and this has biologists worried. Amphibians are highly vulnerable to changes in local ecology.

“We have brought these beautiful frogs into public knowledge. But about 80% of them are outside protected areas and in some places, it is as if nature itself is crying,” Biju, the lead scientist of the Indian amphibian recovery project and a professor at Delhi University, said. 

The Western Ghats — a lush mountain range spread across 1,600 km — is a global bio-diversity hotspot with high species richness. Over the last 15 years, 75 new amphibian species have been discovered from the Ghats. Biju and his team are credited with finding 50 of them.
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Friday, 2 May 2014

Scientists Create Element 117, Which Is 40 Times Heavier Than Lead

Gsi_accelerator
Undated picture released by GSI shows the particle accelerator SIS in Darmstadt, Germany.
Image: GSI, Achim Zschau/Associated Press
Element 117, a super-heavy atom with a long half-life is, according to an international team of scientists, real and ready to take its place on the Periodic Table.
Scientists actually confirmed the existence and lifetime og the element in 2010 thanks to experiments conducted by teams in Russia and the U.S. However, now researchers in Germany and the U.S. have created the actual element, which is reportedly 40 times heavier than lead, according to a report in Phys.org.
It wasn't easy to make element 117, whose temporary name refers to the 117 protons in its nucleus, according to LiveScience. Scientists took 18 months to create the material, berkelium, needed to synthesize it. U.S.-based Oak Ridge National Laboratory (ORNL) created the isotope and then a team at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, blasted it with its accelerator. They then pulled 117 atoms out of the nuclear reactions.
Of the 114 confirmed elements on the Periodic Table, 92 of them occur in nature, the rest have been guessed at, discovered and, in some cases, confirmed and synthesized.
The still-unnamed 117 isn't alone, though. All elements after 104 are considered "Super Heavy Elements" and reside in a portion of the Periodic Table known theoretically as the Island of Stability. Wikipedia describes these elements as a set of "undiscovered heavier isotopes of transuranium elements which are theorized to be much more stable than some of those closer in atomic number to uranium."
While super-heavy elements tend to decay in nanoseconds, those in the island of stability, like 117, have a much longer half-life, which "scientists could then develop for untold practical uses," LiveScience reports.
Periodic Table with six-new-isotopes

Periodic Table with six-new-isotopes. 117 and other super-heavies exist in the "Island of Stability."

First theorized 25 years ago, scientists started synthesizing elements on the table's island of stability at the turn of the 21st century, mostly thanks to the powerful nuclei-colliding capabilities of particle accelerators.
According to the report, 117 still has one more hurdle to clear before full confirmation: the International Unions of Pure and Applied Physics and Chemistry (IUPAPC) has to review the findings and weigh in. No word on how long that will take.
Whatever the outcome, do not expect to buy an element 117 smartphone any time soon (though who wouldn't want one with such a cool name?). Scientists theorize, study and ultimately try to confirm and create these elements to learn more about the nucleus at the heart of every atom.
While we're waiting for the IUPAPC's results, let's see if we can give element 117 a shiny new name. We like "HeavyB" or "Weightonium."
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