Updated: 2009-11-30 17:40:33
*1. The problem statement, all variables and given/known data*
3. A student sits on a stool which can rotate about a vertical axis and is holding a pair of weights, one in each hand. The moment of...
Updated: 2009-11-30 17:07:02
One thing I don't understand is that most of our theories include particles...the oversimplified analogy is, of course, balls on a billiard table. Even the "theory of everything" or String...
Updated: 2009-11-30 13:58:07
A recent experiment at the Department of Energy's Thomas Jefferson National Accelerator Facility has observed that a proton's nearest neighbors in the nucleus of the atom may modify the proton's internal structure. When comparing large nuclei to small nuclei, past measurements have shown a clear difference in how the proton's constituent particles, called quarks, are distributed. This difference is called the EMC Effect........
Updated: 2009-11-24 03:47:02
Last week, I spent over an hour with Ed Cowle, CEO of U.S. Rare Earths, Inc., a privately-held rare earths junior mining company, and Jack Lifton, Founding Editor of The Jack Lifton Report and a consultant to U.S. Rare Earths. The discussion was prompted by an earlier post over at the RareMetalBlog Web site, concerning [...]
Updated: 2009-11-22 23:40:17
[Updated: 11/23/09.]
The Times Online has just published a story on a technology that apparently “has the potential to revolutionise the renewable energy industry by making wind power cheaper and more reliable and greatly increasing the efficiency of wind turbines for electricity companies.”
The driver behind the work, conducted by Dr Markus Mueller and Dr. Alasdair McDonald [...]
Updated: 2009-11-21 14:43:00
: physicsplus The Physics Site for Success Saturday , November 21, 2009 Questions MCQ on Nuclear Physics The following three questions from nuclear physics are simple but are useful in your preparation for entrance : tests 1 Two radioactive samples S 1 and S 2 have half lives 3 hours and 7 hours respectively . If they have the same activity at a certain instant t what is the ratio of the number of atoms of S 1 to the number of atoms of S 2 at the instant t a 9 49 b 49 9 c 3 7 d 7 3 e 1 1 If The number of atoms present at the instant t is N we have N N 0 e λt where N 0 is the initial number , e is the base of natural logarithms and λ is the decay . constant Therefore , activity , d N d t λ N 0 e λt λN If N 1 and N 2 are the number of atoms of S 1 and S 2 respectively when the activities are the same , we have λ 1 N 1 λ 2 N 2 from which N 1 N 2 λ 2 λ 1 But the decay constant λ is related to the half life T as T 0.693 λ Therefore , N 1 N 2 λ 2 λ 1 T 1 T 2 3 7 Option c 2 A nucleus Z X A has mass M kg . If M p and M n denote the mass in kg of proton and neutron respectively , the binding energy in joule is a Z M p A Z M n M c 2 b Z M p Z M n M c 2 c M Z M p A Z M n d M Z M p A Z M n c 2
Updated: 2009-11-20 06:00:05
Earlier today, Science Daily published an article on the use of magnets by a researcher at NIST, Javier Atencia, to create a “new, inexpensive, reusable and highly efficient microfluidic connector“.
Microfluidics involves the control of fluids in very small channels and containers. According to the article:
The NIST connector employs a ring magnet with a O-ring gasket [...]
Updated: 2009-11-16 06:45:08
Over the past few days, Australia’s ABC Radio National broadcast not one, but two items on rare earth metals, to both of which I heartily recommend listening.
The first item was broadcast on the Breakfast program on Friday, and lasts a little over 6 minutes. It’s an introductory piece on the subject, but spends significant time discussing [...]
Updated: 2009-11-15 22:34:42
As you may already know by now, the Magnetics 2010 conference will be held January 28-29, 2010 at the Disney Hilton in Orlando, Florida. Per the folks organizing the conference, the conference “will feature an interactive exhibit hall, the chance to attend pre-conference workshops, unmatched networking/business opportunities and more than 20 technical presentation“. The Conference [...]
Updated: 2009-11-15 00:55:15
My thanks to RareMetalBlog’s Ian London for pointing this article out:
Oct. 27, 2009 – by Tracey Bryant – The University of Delaware has won a $4.4 million grant from the U.S. Department of Energy’s Advanced Research Projects Agency (ARPA-E) to lead a multidisciplinary, multi-institutional research project to develop the next generation of high-performance permanent magnets.
Stronger [...]
Updated: 2009-11-13 03:32:19
Last weekend, Democrat US Senator Chuck Schumer of NY made headlines with his comments on a recent plan to fund a wind farm in Texas, using Federal stimulus money to pay for Chinese-built wind turbines. Rare metals commentator and analyst Jack Lifton has posted a new article on the subject, called “The Rare Earth Crisis [...]
Updated: 2009-11-12 13:31:35
UK Press Association – A “highly innovative” fridge which will use magnets to cool food is being developed as a more environmentally-friendly alternative to current technology, the Carbon Trust has said.
The trust, along with white goods manufacturer Whirlpool, is backing the project to develop a domestic refrigerator based on the scientific principle that certain materials [...]
Updated: 2009-11-08 17:23:41
The Defense Metals Technology Center [DMTC], based in North Canton, Ohio, is hosting its 2nd Annual Strategic Materials Conference [SMC] during Feb 1-2, 2010 in Cleveland, Ohio.
According to the DMTC Web site:
The Defense Metals Technology Center (DMTC) was formed in January, 2007 in order to establish an industrial base capable of affordably producing such strategic [...]
Updated: 2009-11-07 05:58:09
Earlier today, I was pleased to learn that the Organizing Committee of the 21st International Workshop on Rare Earth Permanent Magnets and the Applications [REPM10] announced their first Call for Abstracts. This meeting takes places in Bled, Slovenia from August 29 to September 2, 2010.
Held every two years, the Workshop was inaugurated in 1974 by [...]
Updated: 2009-11-05 07:16:00
: physicsplus The Physics Site for Success Thursday , November 05, 2009 MCQs on Magnetism including EAMCET 2009 Medical Question Some multiple choice questions on magnetism have already been posted on this site . You can access them by clicking on the labe l magnetism’ below this post . Today we will discuss a few more multiple choice questions on magnetism . 1 The period of oscillation of a magnetic needle in a magnetic field is T If an identical bar magnetic needle is tied at right angles to it to form a cross fig the period of oscillation in the same magnetic field will be a 2 1 4 T b 2 1 2 T c 2 T d T 3 e T 2 The period of oscillation T of the single magnetic needle is given by T 2 π I mB where I’ is the moment of inertia of the magnetic needle about the axis of rotation , m’ is the magnetic dipole moment of the needle and B’ is flux density of the magnetic . field When two magnetic needles are tied together to form a cross , the moment of inertia becomes 2I and the magnitude of the magnetic dipole moment becomes m 2 m 2 m√2. Note that magnetic dipole moment is a vector quantity . Two identical vectors each of magnitude m at right angles will yield a resultant magnitude m√2 The
