Hugoniot measurements for polyimide with laser and explosives

Copyright 2003 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas, 10(6), 2475-2479, 2003 and may be found at http://dx.doi.org/10.1063/1.157249

Planar shock wave generated by uniform irradiation from two overlapped partially coherent laser beams

Copyright 2001 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics, 89(5), 2571-2575, 2001 and may be found at http://dx.doi.org/10.1063/1.134218

A Novel ATM/TP53/p21-Mediated Checkpoint Only Activated by Chronic γ-Irradiation

Different levels or types of DNA damage activate distinct signaling pathways that elicit various cellular responses, including cell-cycle arrest, DNA repair, senescence, and apoptosis. Whereas a range of DNA-damage responses have been characterized, mechanisms underlying subsequent cell-fate decision remain elusive. Here we exposed cultured cells and mice to different doses and dose rates of γ-irradiation, which revealed cell-type-specific sensitivities to chronic, but not acute, γ-irradiation. Among tested cell types, human fibroblasts were associated with the highest levels of growth inhibition in response to chronic γ-irradiation. In this context, fibroblasts exhibited a reversible G1 cell-cycle arrest or an irreversible senescence-like growth arrest, depending on the irradiation dose rate or the rate of DNA damage. Remarkably, when the same dose of γ-irradiation was delivered chronically or acutely, chronic delivery induced considerably more cellular senescence. A similar effect was observed with primary cells isolated from irradiated mice. We demonstrate a critical role for the ataxia telangiectasia mutated (ATM)/tumor protein p53 (TP53)/p21 pathway in regulating DNA-damage-associated cell fate. Indeed, blocking the ATM/TP53/p21 pathway deregulated DNA damage responses, leading to micronucleus formation in chronically irradiated cells. Together these results provide insights into the mechanisms governing cell-fate determination in response to different rates of DNA damage

Estimation of 1-D velocity models beneath strong-motion observation sites in the Kathmandu Valley using strong-motion records from moderate-sized earthquakes

The Himalayan collision zone experiences many seismic activities with large earthquakes occurring at certain time intervals. The damming of the proto-Bagmati River as a result of rapid mountain-building processes created a lake in the Kathmandu Valley that eventually dried out, leaving thick unconsolidated lacustrine deposits. Previous stud-ies have shown that the sediments are ~600 m thick in the center. A location in a seismically active region, and the possible amplification of seismic waves due to thick sediments, have made Kathmandu Valley seismically vulnerable. It has suffered devastation due to earthquakes several times in the past. The development of the Kathmandu Valley into the largest urban agglomerate in Nepal has exposed a large population to seismic hazards. This vulnerability was apparent during the Gorkha Earthquake (Mw7.8) on April 25, 2015, when the main shock and ensuing aftershocks claimed more than 1700 lives and nearly 13% of buildings inside the valley were completely damaged. Preparing safe and up-to-date building codes to reduce seismic risk requires a thorough study of ground motion amplification. Characterizing subsurface velocity structure is a step toward achieving that goal. We used the records from an array of strong-motion accelerometers installed by Hokkaido University and Tribhuvan University to construct 1-D velocity models of station sites by forward modeling of low-frequency S-waves. Filtered records (0.1–0.5 Hz) from one of the accelerometers installed at a rock site during a moderate-sized (mb4.9) earthquake on August 30, 2013, and three moderate-sized (Mw5.1, Mw5.1, and Mw5.5) aftershocks of the 2015 Gorkha Earthquake were used as input motion for modeling of low-frequency S-waves. We consulted available geological maps, cross-sections, and borehole data as the basis for initial models for the sediment sites. This study shows that the basin has an undulating topography and sediment sites have deposits of varying thicknesses, from 155 to 440m. These models also show high velocity contrast at the bedrock depth which results in significant wave amplification

CINTRAFOR Working Paper 100

Alaska exports to Japan decreased dramatically during the 1990’s. This decline was caused by a variety of factors including the Japanese recession, a reduced Alaska timber supply, exchange rates, a market shift from green lumber to kiln dried lumber, and increased global competition. However, in 2005 Japan’s GDP, stock market, real estate, and consumer price index were up from the previous year indicating a strong economic recovery. Furthermore, the U.S. Dollar has weakened against the Japanese yen and many economists predict that the U.S. Dollar will continue to decline against the yen due to historically high U.S. fiscal and trade deficits. This will give Japanese companies more purchasing power for U.S. forest products. In addition to economic changes, Japan’s demographics are changing rapidly. In the first half of 2005, Japan’s net population decreased and the population will continue to decline to the 1960’s level of 100 million by 2050. While Japan’s general population is decreasing, the percentage of population over 65 is growing rapidly as the baby boomers reach retirement age. According to a survey published in the Nikkei Weekly Newspaper, one area baby boomers expect to spend money on when they retire is their house. The total size of Japan’s remodel market was 7.0 trillion yen (US$ 60.3 billion) in 2003. The remodel market increased in 2003 and is predicted to increase as more baby boomers retire. As explained above, the Japanese market has shifted from green lumber to kiln dried lumber. Alaska has more than doubled their kiln dry capacity since the late 1990’s and this opens up Japan’s kiln dried lumber market. Additionally, the Ketchikan Wood Technology Center has established Alaska-specific lumber grade marks to differentiate Alaska timber species’ unique characteristics. The Japanese market has always valued quality and there is now an opportunity to communicate Alaska lumber quality by promoting these new grade marks in Japan. The results of this research suggest that many niche markets exist for Alaska forest products: 1. Tract housing power builders Tract housing developments built by a new category of builder called “power builders” have increased in Japan’s urban areas. This is a growing market segment in Japan and these power builders are large enough to import Alaska forest products in large quantities. 2. Kiln dried lumber Alaska has substantially increased its kiln dried lumber capacity recently. Japan’s ten year warranty building requirement has increased demand for kiln dried lumber. There is ample demand for kiln dried lumber in both the 2x4 and post and beam housing markets. 3. Lamstock market There has been an increase in demand for engineered wood and the number of Japanese glulam manufacturers. The results of the Ketchikan Wood Technology Center Alaska species testing program have shown Alaska lumber has superior strength properties compared with many other species making it suitable for lamstock. 4. Pre-cut lumber market Almost 75 percent of Japanese post and beam starts used pre-cut lumber. Japan’s pre-cut lumber mills are a strong market to target with lumber sizes that could be used with their pre-cut lumber machines. The lumber sizes vary based on the application. 5. Alaska yellow-cedar for sill plate (dodai) Due to its natural decay resistant properties, Alaska yellow-cedar is very popular for sill plates and other structural lumber used in ground contact applications in Japan. 6. Alaska yellow-cedar for garden accessories and tubs Alaska yellow-cedar’s decay resistant properties make it an excellent species for outdoor garden accessories such as decking and decking accessories, benches, gazebos, and lattice. As explained earlier, there are a lot of retirees in Japan and this number will be increasing. Many retirees spend more time in their gardens and the demand for garden accessories is expected to increase. Also, Alaska yellow-cedar is considered a substitute for hinoki, (Japanese falsecypress). Japanese people traditionally take a bath daily. Soaking tubs are especially popular in Japan and most detached houses have one. An Alaska yellow-cedar tub could be developed and positioned as an upscale alternative to a hinoki tub. 7. Home improvement market for retirees Japan’s baby boomers are approaching retirement age. Many Japanese retiring workers receive a large lump sum payment, which they often use to improve their house. The senior home improvement market is expected to grow substantially as baby boomers start to retire. 8. Remodel market The remodeling market is expanding. There is an opportunity for lumber producers to collaborate with builders specializing in remodels, architects, and designers to develop higher quality products to sell to Japan. 9. Wood Chips It has been estimated that over 2.3 million acres of timber have been affected in the Kenai Peninsula by the spruce bark beetle. One potential application for beetled killed spruce is wood chips. Japan has one of the largest pulp and paper markets in the world. 10. Gift Market Japan’s gift market has strong potential for smaller wood products and craft items. This market offers tremendous opportunity for smaller wood products that can be packaged and shipped easily. It would also make the gift more attractive if wood items are bundled with other “made in Alaska” items, such as smoked salmon. 11. Brand Strategy As described above, the Ketchikan Wood Technology Center has registered proprietary grade marks for Alaska species. These grade marks are “Alaska Hem”, “Alaska Yellow Cedar”, and “Alaska Spruce”. These three grade marks should be developed into a brand that communicates the quality of Alaska forest products to forest products manufacturers, pre-cutters, and homebuilders