BLOGS

All Posts (6495)

Sort by

Cause It's Cap...

Posted by Reginald L. Goodwin on March 28, 2014 at 6:00am

...and, it's Friday! One more week to geek on "Winter Soldier." I'd buy on Fandango: after the east coast nuclear winter, people will be stir crazy from telecommuting and need to get out...and see real people again.

 The analysis below is the reason why you shouldn't take a physics person to the movies with you...just kidding, and my wife sadly has no choice in the matter. We'll behave, promise. Just don't ask questions like these.





At the end, Cap throws his shield at the Winter Soldier – because that’s what Captain America does. But wait! The Winter Soldier just catches the shield and throws it right back at Captain America. The real cool part is what happens when Cap catches the shield. The impact is strong enough to push him back a little bit. Is this enough to get an estimate for the mass of the shield? I think so.



Sliding Back

This is really a multi-part problem. First, the shield is thrown by the Winter Soldier. I don’t really care about the throwing motion. Next, the shield moves through the air to Captain America and collides with him. This gives him some recoil velocity. However, Cap is standing on the ground such that his recoiling body is slowed down to a stop by friction.



It might not seem to be the best place to start, but I am going to start backwards. Let’s look at Captain America sliding after the impact with the shield. By estimating the frictional force and the sliding distance, I can get a value for the recoil speed after the impact.



In this first problem, I can just consider Captain America as a block with some initial speed moving across the ground. Here is a force diagram while he is slowing down (after the impact).


The forces in the vertical direction must add up to zero since Cap doesn’t accelerate up or down. This means that I can find the force the ground pushes up on him:


Why do I need this force pushing up (usually called the Normal force)? If I use the typical model for sliding friction, the magnitude of the frictional force can be determined by:


 Wired: How Much Does Captain America’s Shield Weigh? Rhett Allain

Read more…

Nano Fingerprints...

Posted by Reginald L. Goodwin on March 26, 2014 at 5:00am
The process of producing anti-counterfeit nano-fingerprints based on randomly distributed silver nanowires.
[1] Silver nanowires (AgNWs) are prepared by the self-seeding method and an amorphous silica shell is coated on the surface using tetraethyl orthosilicate (TEOS).
[2] Fluorescein isothiocyanate (FITC) and rhodamine B-isothiocyanate (RITC) are attached covalently to the surface of the pre-formed silica shell by allowing the formation of covalent bonds between the silica surface and 3-aminopropyltrimethoxysilane (APTMS).
[3] A photolithographic process is used to inscribe the direction and target markers on the surface of the PET film. The orientation marker (“KAIST”) can be used to determine the correct direction of the PET film. The target marker (“X”) has an empty space in its central region where AgNWs are loaded to generate fingerprints.

Counterfeiting is a steady and increasingly important problem that occurs in nearly every trade and industry. Recognizing the difficulty in distinguishing counterfeit goods from genuine products, new nanoscale technologies are being developed to prevent and identify this illegal practice. Using dye-coated one-dimensional (1D) nanowires, researchers at the Korea Advanced Institute of Science and Technology (KAIST) in South Korea have demonstrated that randomly distributed nanowires can generate unique and simple barcode patterns readily applicable by many to anti-counterfeiting.



Reporting in Nanotechnology, nanoscale fingerprint patterns are generated by simply casting fluorescent dye-coated silver nanowires onto a transferrable flexible polyethylene terephthalate (PET) film. The direction and target markers ("KAIST" and "X") are patterned by a photolithographic technique to provide positional information for identification and the nanowires are cast onto it. Then, using an optical microscope, the resulting unique fingerprint patterns can be visually authenticated in a simple and straightforward manner, as shown fully in the figure above.


 Nano Tech Web: Combatting counterfeit goods with nanoscale fingerprints
Read more…

Nuclear Quantum Computers...

Posted by Reginald L. Goodwin on March 25, 2014 at 5:30am
Photon-shaping technique could lead to "nuclear" quantum computers. (Courtesy: iStockphoto/polygraphus)

A way of modulating the waveforms of individual, coherent high-energy photons at room temperature has been demonstrated by researchers in the US and Russia. The advance opens the way for new quantum-optics technologies capable of extremely high-precision measurements, as well as the possibility of <>quantum-information systems based on nuclear processes. The new approach could also be useful for those doing fundamental research in a variety of areas, ranging from the role of quantum phenomena in biological processes to fundamental questions in quantum optics itself.



The technique was developed by Olga Kocharovskaya, Farit Vagizov and colleagues at Texas A&M University and the Kazan Federal University. Their set-up bears some similarity to a Mössbauer spectroscopy experiment. A sample of radioactive cobalt-57 decays to an excited state of iron-57, which then decays by emitting a 14.4 keV "soft" gamma-ray photon. This photon can then be absorbed and re-emitted by a nearby stainless-steel foil containing iron-57. Because of the Mössbauer effect, no energy is lost in the recoil of the stainless-steel lattice and the photon is emitted at 14.4 keV with very little spectral blurring.



As the foil absorbs and re-emits the photons, it is vibrated at megahertz frequencies. By making clever use of the Doppler effect, the team is able to shape a single photon into a double pulse and even a train of ultrashort pulses. This makes it possible to use the gamma-ray photons to encode quantum information in a "time-bin qubit" – quantum bits in which information is encoded in terms of the relative arrival time of pulses.



 Physics World:
Gamma-ray shaping could lead to 'nuclear' quantum computers

Read more…

#TheWalkingDead Season #Finale Predictions #amc

Posted by Gerald Dean Rice on March 24, 2014 at 9:30pm

The following is a list of people who will die:

  1.        Maggie
  2.        Sasha
  3.        At least 2 guys in Darryl’s group
  4.        Some guy you see in the background once

 

Now what’s going to actually happen? After the events following the group’s hasty exit from the prison, surprisingly few people died. For a show that has no compunctions about killing main characters, there’s been too much build-up for all these main characters to make it. Combo that with the fact that Terminus looks quiet (one might say almost too quiet) that can only be foreshadowing that something grizzly is going to happen.

Read the rest here.

Read more…

RGDX...

Posted by Reginald L. Goodwin on March 24, 2014 at 6:39am

A little something to do while vegging on the couch (nothing on the "boob tube" except COSMOS, really).



Controlling a lab from home



The Remote Control Glow Discharge (RGDX) is a plasma that you can control from the comfort of your browser. YOU have control of the entire experiment including the gas pressure inside the tube, the voltage produced by the power supply that makes the plasma, and the strength of an electromagnet surrounding the plasma. You can perform experiments from any computer anywhere in the world!




In 2002, we began developing plasma sources for educational purposes and one of our devices won 2nd place in the National Apparatus Competition sponsored by the American Association of Physics Teachers. In 2003, we began controlling our plasma sources by computer for a plasma exhibit in a science museum. The progression of this has led to remote control of a plasma from any location by anyone with an internet connection. This type of control could serve as an experimental component of an online physics class or for a school that typically does not have plasma physics equipment.



As with all other Science Education Department labs, the RGDX has been developed in large part by high school and undergraduate interns.



The Remote Glow Discharge Experiment was officially released to the public on 3/12/2014. The story can be found here.



 PPPL: Remote Glow Discharge Experiment (RGDX)

Read more…

Children's Home...

Posted by Reginald L. Goodwin on March 23, 2014 at 5:51am


Established in 1847, the Children's Home provides a range of services and programs giving hope and healing to abused and neglected children in the Hudson River Region. The Children's Home served 397 children and their family members last year. The Home provides a full range of residential services including campus-based care, community-based group homes and boarding homes, and independent living apartments. It also provides regular foster care and intensive therapeutic foster homes.



Throughout our 167 year history, the underlying mission of the Children’s Home of Poughkeepsie has remained the same: The Home is dedicated to providing a safe and nurturing environment that improves lives and empowers at-risk children and families in the Hudson Valley and surrounding communities.



I did this presentation on Saturday, 22 March at the behest of the local Alpha Kappa Alpha alumni chapter. I have done such presentations before. I was more than happy to do it.



It was a focused audience of five young men and three young women. They participated well, and at least a few of them said they were going to purchase electronics snap kits from "The Shack." I came away encouraged and inspired by the curiosity of these young people in spite of their challenging circumstances. Especially in an era of error and pseudoscience propagated as alternate "truth" more outreach like this is needed: these are the "meek who will inherit the earth" and will need the tools to manage it.



Physics teachers: all the links in the embed are active, including those in the pictures of slides 8 and 12. If you want the Power Point version with all the "bells and whistles" of this embed, email: physics4thecool@gmail.com. Please attribute the source. My reference to Korea on slide 4 was a quote from "The Smartest Kids in the World and How They Got That Way," by Amanda Ripley and not meant to be derisive: the Korean children spend 16 hours a day in school M-F and 8 hours on Saturday. They are brilliant via focus and immersion.

 I used parts from Electronics 101 and Electronics 303 kits purchased from Radio Shack. Apparently, Radio Shack only carries the Electronics 101 snap kit. I'd try their service number for the more advanced Electronics 303. However, Amazon carries comparable manipulatives: SC-100,  SC-300 and SC-750. Good luck.
Read more…

The Moon's North Pole...

Posted by Reginald L. Goodwin on March 22, 2014 at 12:02pm


On 18 June 2009, NASA launched the Lunar Reconnaissance Orbiter (LRO) to map the surface of the Moon and collect measurements of potential future landing sites as well as key science targets. After two and a half years in a near-circular polar orbit, LRO entered an elliptical polar orbit on 11 December 2011 with a periapsis (point where the LRO is closest to the surface) near the south pole, and the apoapsis (point where LRO is furthest from the surface) near the north pole. The increased altitude over the northern hemisphere enables the two Narrow Angle Cameras (NACs) and Wide Angle Camera (WAC) to capture more terrain in each image acquired in the northern hemisphere. As a result, the Lunar Reconnaissance Orbiter Camera (LROC) archive now contains complete coverage from 60°N to the north pole (except of course for areas of permanent shadow) with a pixel scale of 2 meters.



The LROC team assembled 10,581 NAC images, collected over 4 years, into a spectacular northern polar mosaic. The LROC Northern Polar Mosaic (LNPM) is likely one of the world’s largest image mosaics in existence, or at least publicly available on the web, with over 680 gigapixels of valid image data covering a region of the Moon (2.54 million km², 0.98 million miles²) slightly larger than the combined area of Alaska (1.72 million km²) and Texas (0.70 million km²) -- at a resolution of 2 meters per pixel! To create the mosaic, each LROC NAC image was map projected on a 30 m/pixel Lunar Orbiter Laser Altimeter (LOLA) derived Digital Terrain Model (DTM) using a software package called Integrated Software for Imagers and Spectrometers (ISIS). A polar stereographic projection was used in order to limit mapping distortions when creating the 2-D map. In addition, the LROC team used improved ephemeris provide by the LOLA and GRAIL teams and an improved camera pointing model to enable accurate projection of each image in the mosaic to within 20 meters.



 NASA: Lunar Reconnaissance Orbital Camera

Read more…

Peer Review...

Posted by Reginald L. Goodwin on March 21, 2014 at 5:00am
Timberwood Park, San Antonio, TX: Caveat emptor

Yesterday (17 March), researchers from the Background Imaging of Cosmic Extragalactic Polarization (BICEP2) telescope at the South Pole revealed that they have detected the first evidence for the primordial B-mode polarization of the cosmic microwave background (CMB). The astronomers claimed that the primordial B-mode polarization signal – which is related to primordial gravitational waves that flowed through the early universe – is the first direct evidence for cosmic inflation and has been measured to a statistical certainty of 3σ. Now, cosmologist and Perimeter Institute director Neil Turok, who worked on an inflationary model of his own with Stephen Hawking in the 1990s, urges caution and says that extensive experimental confirmation is necessary before BICEP2's results can be considered as evidence for inflation.



"If...and it's a big if...this is true, it would be spectacular evidence for what happened at the Big Bang," Turok told physicsworld.com. While he agreed that at first glance, the BICEP2 observations are in keeping with inflation "as suggested over 30 years ago, wherein space–time would resonate with the aftershocks of inflation and would ring like a bell", a closer look at the discrepancy between the new results and previous data from the Planck and WMAP telescopes is what worries Turok. Indeed, the tensor-to-scalar ratio of 0.20 that BICEP2 measured is considered to be significantly larger than that expected from previous analyses of data. But the BICEP2 researchers said in their press conference yesterday that they believe certain tweaks could be made to an extension of the ΛCDM cosmological model that could make the two results agree.



"But these tweaks would be tremendously ugly....and in fact, I believe that if both Planck and the new results agree, then together they would give substantial evidence against inflation!" exclaims Turok, further explaining that "[we] must be careful before we treat them as true".



"Extraordinary claims requires extraordinary evidence." Carl Sagan.

 Even though Tuesday's announcement was exciting news, and I really want it to be true, it might not be. After the Scientific Method, this is the rigor of peer review and the necessity of it. Without it, we march down the primrose path of pseudoscience and created entities like the Discovery Institute ("intelligent design") and World Science Database (which purports that the Special and General Theory of Relativity have been "disproved"  despite yesterday, I was discussing superconducting quantum interference devices - SQUID's). Both organizations are of "sounding brass and tinkling cymbal" to quote Corinthians. The Science Channel - when it's not suggesting UFO close encounters - promotes the tagline "question everything." We really should.



 Physics World: Neil Turok urges caution on BICEP2 results

Read more…

MISSED THE LAST "DISCUSSIONS FROM THE OTHERHOOD" SHOW? THAT'S OK - CATCH US ON iTUNES!

Posted by Penelope on March 20, 2014 at 1:09am

That's Right! The OTHER SCI FI Talkshoe Live Podcast "Discussions from the Otherhood which we record just about every Saturday at 4pm EST is now a free Podcast on iTunes!

To find us go to:

http://itunes.apple.com/WebObjects/MZStore.woa/wa/viewRoom?fcld=529293810

And initiate a Search for "Other Sci Fi" in the Podcasts section of the menu.

Listen in and maybe... just maybe you'll decide to join us one of these Saturday afternoons!

If you have any problems locating us at iTunes, contact me here or at p.flynn@otherscifi.com for additional information!

~P.Flynn

Read more…

SQUID...

Posted by Reginald L. Goodwin on March 19, 2014 at 2:58pm
Micrograph of a SQUID amplifier, made at NIST in 2012, that is part of a circuit used to read signals from arrays of superconducting sensors. Small currents generated by the sensors are carried and amplified in the coils, which create magnetic fields detected by the SQUID (two small squares in the center of the image).
Credit: NIST

From humble beginnings in a series of accidental discoveries, SQUIDs have invaded and enhanced many areas of science and medicine, thanks, in part, to the National Institute of Standards and Technology (NIST).



SQUIDs—short for superconducting quantum interference devices—are the world's most sensitive magnetometers and powerful signal amplifiers, with broad applications ranging from medicine and mining to cosmology and materials analysis.



Physicists from around the world celebrated last week* to mark the 50th anniversary of the first journal paper introducing the SQUID, published in February 1964.

Celebrants heard about the use of SQUIDS to measure brain activity in Finland, discover mineral deposits leading to a large silver mine in Australia, and detect faint light from the early moments of the universe from telescopes all over the world.



SQUIDs measure magnetic fields based on quantum properties created when a superconducting circuit loop, in which electricity flows without resistance, is interrupted with one or two short sections of resistive material. The current across the resistive section varies predictably, based on the strength of the external magnetic field, making the device an exquisitely sensitive detector of magnetic fields. Typically, SQUIDs need to be cooled to cryogenic temperatures below 4 kelvins (-269 degrees Celsius) with liquid helium.



The SQUID was invented at Ford Scientific Laboratories in the 1960s but was further developed at NIST (then called the National Bureau of Standards). James Zimmerman co-invented one type of SQUID (the RF-SQUID) and coined the term while at Ford, before joining NIST where he worked in the 1970s and 1980s.



 NIST: Magnetic Attraction: Physicists Pay Homage to the SQUID at 50

Read more…

AfroFuturism?

Posted by Arnold L. Johnson on March 19, 2014 at 1:21pm

I will ask the question.

What is Afrofuturism?, the crux and purpose of it? Is it a perspective or a cultural designation?

My interest is on material culture, cultural immersion, perhaps an ideal that embraces us all but not necessarily a racial/cultural identifier.  So, what's the vibe?

I ask because I am an artist, interested in design (material culture) that we live with day to day. And I'm tired of waiting for the future to come, thinking about contrasting with the present.

Read more…

Five Sigma...

Posted by Reginald L. Goodwin on March 18, 2014 at 4:30am
The 10-meter South Pole Telescope and the BICEP (Background Imaging of Cosmic Extragalactic Polarization) Telescope against the Milky Way. BICEP2 recently detected gravitational waves in the cosmic microwave background, a discovery that supports the cosmic inflation theory of how the universe began. (Photo: Keith Vanderlinde, National Science Foundation)

The detection of gravitational waves by the BICEP2 experiment at the South Pole supports the cosmic inflation theory of how the universe came to be. The discovery, made in part by Assistant Professor Chao-Lin Kuo, supports the theoretical work of Stanford's Andrei Linde.



Almost 14 billion years ago, the universe we inhabit burst into existence in an extraordinary event that initiated the Big Bang. In the first fleeting fraction of a second, the universe expanded exponentially, stretching far beyond the view of today's best telescopes. All this, of course, has just been theory.



Researchers from the BICEP2 collaboration today announced the first direct evidence supporting this theory, known as "cosmic inflation." Their data also represent the first images of gravitational waves, or ripples in space-time. These waves have been described as the "first tremors of the Big Bang." Finally, the data confirm a deep connection between quantum mechanics and general relativity.



 Stanford News:
New evidence from space supports Stanford physicist's theory of how universe began
Harvard Center for Astrophysics: First Direct Evidence of Cosmic Inflation

Read more…

Dark Matter and Dino...

Posted by Reginald L. Goodwin on March 17, 2014 at 3:55pm
Artist's impression of a comet striking the Earth. (Courtesy: iStock/PaulPaladin)

Two theoretical physicists in the US have made a surprising connection between dinosaur extinction and dark matter. Lisa Randall and Matthew Reece of Harvard University believe that some of this mysterious invisible matter – which makes up 85% of all matter in the universe – could exist in a special form that affects the rate at which comets strike our planet. A comet crashing into Earth about 66 million years ago is one possible reason why these giant creatures died off.



Comets have smashed into Earth throughout its history, creating huge craters and possibly causing mass extinctions, such as that which befell the dinosaurs. Many of these comets come from the Oort cloud, which is a huge halo of small icy objects that surrounds the Sun, out to a distance of about one light year. But rather than being entirely random, there is some evidence that the frequency of comet impacts oscillates on a timescale of about 35 million years.



Although this oscillation is not certain, if it is true, there could be something on that timescale that affects the rate at which comets from the Oort cloud are sent towards Earth. Two possible explanations have been proposed so far. One – dubbed the "nemesis hypothesis" – involves the gravitational pull of an as-yet-undiscovered distant companion star to the Sun. The other involves the oscillating pull of the dense galactic disc as the solar system crosses and re-crosses the plane of the Milky Way.


Read more…

Living Well...

Posted by Reginald L. Goodwin on March 16, 2014 at 10:43am


When I was in elementary school in the public schools of New York City, I distinctly remember that it was important for me to be athletic — in particular, to be able to run fast. I was encouraged by all around me. My reward was the respect and admiration of classmates and especially my streetmates.



In junior high school it was important for me, now that I was certified the “fastest on the block,” to slam-dunk a basketball. To do this you have to jump high and palm the basketball. On April 17, 1973, I was the first in my grade to slam-dunk a basketball. I then asked myself, “Is this all there is to it?” The answer is basically yes, yet one can imagine creative variations such as a 360-degree pirouette in midair preceding the dunk, but you still score only two points.



About the same time, I learned that light, traveling at 186,282 miles per second, moves too slowly to escape from the event horizon of a black hole. This was more astonishing to me than a 360-degree slam-dunk. I soon became scientifically curious and read everything I could find about the universe. I began to see myself as a future scientist — in particular, an astrophysicist. It became a deeply seated dream.



I shortly came to the shattering awareness that few parts of society were prepared to accept my dreams. I wanted to do with my life what people of my skin color were not supposed to do. As an athlete, I did not violate society’s expectations since there was adequate precedent for dark-skinned competitors in the Olympics and in professional sports. To be an astrophysicist, however, became a “path of most resistance.” I began to wonder whether I originally wanted to be an athlete more from society’s interest rather than my own. My brother, Stephen, today a professional artist, could run faster and jump higher than I could. He, too, felt these forces of society.



In high school, nobody probed further about how I became captain of the wrestling team. But when I became editor-in-chief of my school’s annual Physical Science Journal, my qualifications were constantly queried. And when I was accepted to the college of my choice, I was continually asked for my SAT scores and grade point average. Indeed, one fellow student, who worked in the office of the guidance counselor, threatened to find the file in the school records to read my scores himself, if I didn’t tell.



When I first entered graduate school, before transferring to Columbia, I was eager to pursue my dreams of research astrophysics. But the first comment directed to me in the first minute of the first day, by a faculty member whom I had just met was, “You must join our department basketball team.” As the months and years passed, faculty and fellow students, thinking that they were doing me a favor, would suggest alternative careers for me.



“Why don’t you become a computer salesman?”



“Why don’t you teach at a community college?”



“Why don’t you leave astrophysics and academia? You can make much money in industry.”



At no time was I perceived as a future colleague, although this privilege was enjoyed by others in graduate school.



When combined with the dozens of times I have been stopped and questioned by the police for going to and from my office after hours, and the hundreds of times I am followed by security guards in department stores, and the countless times people cross the street upon seeing me approach them on the sidewalk, I can summarize my life’s path by noting the following: in the perception of society, my athletic talents are genetic; I am a likely mugger-rapist; my academic failures are expected; and my academic successes are attributed to others.



 Book Excerpt: The Sky is Not the Limit, by Neil deGrasse Tyson on BillMoyers.com
Site: COSMOS: A SpaceTime Odyssey
Mother Jones: Neil deGrasse Tyson on "Cosmos" (source of podcast below)

Read more…