FOR IMMEDIATE RELEASE-- JULY 22, 2003
Physics designed to shock – shock waves in medicine, exploration of the universe and the hunt for fusion power
The American Physical Society Topical Group on Shock Compression of Condensed Matter will hold its biennial conference in Portland, OR, from July 20-25. Topics include: the targeting and destruction of cancer cells, needle-free drug delivery, making solid hydrogen, progress toward fusion, and watching the instantaneous freezing of water.
Shock compression studies examine the effects of shock waves on materials of scientific and engineering importance. Shocks can be produced by high-speed impacts or intense explosions. Study of shock waves began as a part of the nuclear weapons program, but the benefits from this new field of science have been far reaching. Some of the exciting topics that will be presented at this conference include:
Shock Waves – A New Medical Tool (Special Session)
Understanding shock waves in biology and medicine is a new challenge and a new opportunity for shock compression science. Biological tissues are fundamentally different and considerably more complicated than the liquids and solids normally studied by shock compression. Laser surgeries generate shock waves in living tissues, causing both mechanical and chemical changes. The shock waves can compress biological molecules and change the pH and ionic strength of the aqueous media, and can result in wanted and unwanted chemical and biological effects including irreversible damage via denaturing proteins, tearing tissues and killing living cells.Session G2 - July 22, 09:00
How shocks force tissue
Needle-free drug delivery
(Figure 1 [PDF] shows a protein from a shock compression point-of-view. It is full of internal space that can be squeezed out by shock compression.)
Hydrogen Compressed to a Solid
Understanding highly compressed hydrogen is vital in efforts to achieve laser-driven fusion, processes in stars and the role of hydrogen in more everyday settings. Discovery of the properties of highly compressed hydrogen has been a major goal and source of competition in the international shock wave community. A highlight of the conference will be a symposium on the properties of fluid hydrogen at very high pressures and temperatures.
Hydrogen is the simplest and most abundant atom in the universe. Fusion of hydrogen (or its isotope deuterium, known as heavy hydrogen) into helium powers the stars, and is the fuel for the hoped-for fusion power of the future here on Earth. Its properties under high shock compression near 100 GPa (a million times atmospheric pressure or about 15 million psi) and 10000 degrees K have been a subject of intense experimental and theoretical effort for most of the past decade. Despite this, a controversy still exists as to its equation of state (the relationship between pressure, density, and temperature). Resolving this issue is important for basic condensed matter physics and the design of laser-driven fusion experiments. The symposium will feature lectures by leading experimentalists and theoreticians from the U.S. and Russia on progress and challenges in understanding the surprisingly complex behavior of hydrogen at extreme conditions.
Instantaneous Freezing of Water
Daniel Dolan, a graduate student at Washington State University (and now on the staff of Sandia National Laboratory) has obtained the first pictures of freezing of water on a sub-microsecond time scale. In this case the water was induced to freeze by subjecting it to pressures up to 36,000 atmospheres and taking pictures through quartz windows. The "ice" condenses not as the familiar crystals, but apparently as filaments of "Ice 7", as shown in Figure 2 (PDF). Session S4
Special Review Lectures
There will be a series of plenary lectures presented by the some of the most renowned scientists working in this exotic field.
The American Physical Society (www.aps.org) is a non-profit membership organization working to advance and diffuse the knowledge of physics through its outstanding research journals, scientific meetings, and education, outreach, advocacy and international activities. APS represents over 51,000 members, including physicists in academia, national laboratories and industry in the United States and throughout the world. Society offices are located in College Park, MD (Headquarters), Ridge, NY, and Washington, DC.