Experiments with an 834 m ring laser interferometer

R. B. Hurst, G. E. Stedman, K. U. Schreiber, R. J. Thirkettle, R. D. Graham et al.<br/> An ultralarge ring HeNe ring laser gyroscope, UG-2, with area 834 m and dimensions 39.7 x 21 m, has been built underground at Cashmere Cavern, Christchurch, New Zealand (latitude 43.575 degrees ). Earth rotation is sufficient to unlock it, giving a Sagnac frequency of 2.18 kHz. Supermirrors are us … [J. Appl. Phys. 105, 113115 (2009)] published Fri Jun 5, 2009.

Two paralleled BaSrTiO ferroelectric varactors series connected coplanar waveguide microwave phase shifter

Su Sheng, Peng Wang, Xin Chen, Xiao-Yu Zhang, and C. K. Ong<br/> A distributed phase shifter of coplanar wave mechanicsguide (CPW) using ferroelectric (BaSrTiO) film varactors with parallel-plate electrodes is presented. In order to satisfy the requirement of small dimension of the parallel-plate varactor for the design of phase shifter and impedance match of the circuit, … [J. Appl. Phys. 105, 114509 (2009)] published Fri Jun 5, 2009.

Magnetic response of core-shell cobalt ferrite nanoparticles at low temperature

K. Maaz, M. Usman, S. Karim, A. Mumtaz, S. K. Hasanain et al.<br/> Cobalt ferrite nanoparticles (size: 264 nm) have been synthesized by coprecipitation route. The coercivity of nanoparticles follows a simple model of thermal activation of particle moments over the anisotropy barrier in the temperature range of 30300 K in accordance with Kneller’s law; however, at … [J. Appl. Phys. 105, 113917 (2009)] published Fri Jun 5, 2009.

Characterizing the light guiding of fluorescent concentrators

Jan Christoph Goldschmidt, Marius Peters, Martin Hermle, and Stefan W. Glunz<br/> Fluorescent concentrators have gained new research interest recently. The development of new material systems for this type of solar concentrator requires the testing of a wide range of materials. The most important characteristic to be tested is the ability of the concentrators to guide light to th … [J. Appl. Phys. 105, 114911 (2009)] published Fri Jun 5, 2009.

Qinetiq staff to strike

The Register: British staff at Qinetiq, the company formed from an uneasy mixture of privatised UK Ministry of Defence (MoD) research facilities and profitable US war-tech companies, have voted to strike in protest at pay freezes and redundancies.

Prospect, which represents some 2,000 of Qinetiq’s UK staff - whom it describes as “specialists” - says that a strike ballot gave a result of 72 per cent in favour of strike action after management announced a pay freeze for 2009. The union had already said its members were “outraged” after 400 British job losses were announced last month.

Making math kid friendly

NPR: Students are counting down the days until the start of summer vacation, but is there a way to convince kids to do math over the break? Ira Flatow talks with Danica McKellar, Wonder Years actress turned math book author, about sharpening students’ math skills.

Slabs Do Not Go Gently

Science: In geology textbooks, the fate of the oceanic crust seems straightforward. The ocean floor is created by upwelling of lighter magma at spreading ridges. The magma cools as it moves away from the ridge, forming a stiff layer or “plate” called the oceanic lithosphere. Having increased in density, it then descends back into the mantle in trench regions.

Precise seismic tomography studies have revealed that many descending slabs have a more complex evolution and have developed tears, detached from the surface plate, or even broken up into fragments.

In last week’s Science, Obayashi and colleagues not only show clear tomographic evidence for the development of a vertical tear under southwest Japan, but have also found evidence for ongoing plate rupturing. The authors correlated the images directly with measurements of stress revealed by active seismic sources.

Related Link
Tearing of Stagnant Slab

Refurbishing US nuclear warheads is now behind schedule

Los Angeles Times: A decade-long effort to refurbish thousands of aging nuclear warheads built more than 20-years-ago has run into serious technical problems that have forced delays.

The $200-million-a-year refurbishment program involves a type of warhead known as the W76, which is used on the Navy’s Trident missile system and makes up more than half of the deployed warheads in the US stockpile.

In February, the Energy department’s National Nuclear Security Administration announced that the “first refurbished W76 nuclear warhead had been accepted into the US nuclear weapons stockpile by the Navy.”

But no delivery was ever made. The warhead is still in pieces at the Energy Department’s Pantex plant in Amarillo, Texas, according to an engineer at the facility.

The hold-up in deploying the warhead is not connected to any missing expertise regarding how to build a nuclear device, but how to manufacture one of the other warhead components. Delays in the program could extend the refurbishment program by another 10 years.

If Greenland’s ice sheets melt northeast US will suffer say scientists

New York Times: “In the debate over global warming, one thing is clear: as the planet gets warmer, sea levels will rise. But how much, where and how soon? Those questions are notoriously hard to answer.

Scientists at the National Center for Atmospheric Research, in Boulder, Colo., are now adding to the complexity with a new prediction. If the melting of Greenland’s ice sheets continues to accelerate, they say, sea levels will rise even more in the northeastern United States and Maritime Canada than in other areas around the world.

The researchers, Aixue Hu and Gerald A. Meehl, based their predictions on runoff data from Greenland and an analysis of ocean circulation patterns.”

SI Units

physics theory uses the International System of Measurements (SI), as does most of science. This introduction to the SI units provides a foundation for the units that are used to quantify the physical qualities of the universe.