Property Studies of Alaskan Silts in the Matanuska Valley, Big Delta, and Fairbanks Areas

The study of four Alaskan areas was begun in the summer of 1954 under a program sponsored by the Office of Naval Research. The Iowa State College Engineering Experiment Station directed the study in collaboration with the Department of Geology, Iowa State College. The program was initiated to: 1. Determine the distribution of engineering soil materials m four Alaska areas. 2. Determine the engineering properties and trafficability characteristic; of these materials. 3. Determine the feasibility and best methods of stabilizing these materials for use as road and airfield building material. 4. Further the studies of geology of Alaska. 5. Attempt a correlation of the engineering and geologic properties of the Alaskan materials with similar materials in the Midwest United States

Simultaneous Observations of the Chromosphere with TRACE and SUMER

Using mainly the 1600 angstrom continuum channel, and also the 1216 angstrom Lyman-alpha channel (which includes some UV continuum and C IV emission), aboard the TRACE satellite, we observed the complete lifetime of a transient, bright chromospheric loop. Simultaneous observations with the SUMER instrument aboard the SOHO spacecraft revealed interesting material velocities through the Doppler effect existing above the chromospheric loop imaged with TRACE, possibly corresponding to extended non-visible loops, or the base of an X-ray jet.Comment: 14 pages, 10 figures, accepted by Solar Physic

Two-Dimensional Spectroscopy of Photospheric Shear Flows in a Small delta Spot

In recent high-resolution observations of complex active regions, long-lasting and well-defined regions of strong flows were identified in major flares and associated with bright kernels of visible, near-infrared, and X-ray radiation. These flows, which occurred in the proximity of the magnetic neutral line, significantly contributed to the generation of magnetic shear. Signatures of these shear flows are strongly curved penumbral filaments, which are almost tangential to sunspot umbrae rather than exhibiting the typical radial filamentary structure. Solar active region NOAA 10756 was a moderately complex, beta-delta sunspot group, which provided an opportunity to extend previous studies of such shear flows to quieter settings. We conclude that shear flows are a common phenomenon in complex active regions and delta spots. However, they are not necessarily a prerequisite condition for flaring. Indeed, in the present observations, the photospheric shear flows along the magnetic neutral line are not related to any change of the local magnetic shear. We present high-resolution observations of NOAA 10756 obtained with the 65-cm vacuum reflector at Big Bear Solar Observatory (BBSO). Time series of speckle-reconstructed white-light images and two-dimensional spectroscopic data were combined to study the temporal evolution of the three-dimensional vector flow field in the beta-delta sunspot group. An hour-long data set of consistent high quality was obtained, which had a cadence of better than 30 seconds and sub-arcsecond spatial resolution.Comment: 23 pages, 6 gray-scale figures, 4 color figures, 2 tables, submitted to Solar Physic

Evolution and Flare Activity of Delta-Sunspots in Cycle 23

The emergence and magnetic evolution of solar active regions (ARs) of beta-gamma-delta type, which are known to be highly flare-productive, were studied with the SOHO/MDI data in Cycle 23. We selected 31 ARs that can be observed from their birth phase, as unbiased samples for our study. From the analysis of the magnetic topology (twist and writhe), we obtained the following results. i) Emerging beta-gamma-delta ARs can be classified into three topological types as "quasi-beta", "writhed" and "top-to-top". ii) Among them, the "writhed" and "top-to-top" types tend to show high flare activity. iii) As the signs of twist and writhe agree with each other in most cases of the "writhed" type (12 cases out of 13), we propose a magnetic model in which the emerging flux regions in a beta-gamma-delta AR are not separated but united as a single structure below the solar surface. iv) Almost all the "writhed"-type ARs have downward knotted structures in the mid portion of the magnetic flux tube. This, we believe, is the essential property of beta-gamma-delta ARs. v) The flare activity of beta-gamma-delta ARs is highly correlated not only with the sunspot area but also with the magnetic complexity. vi) We suggest that there is a possible scaling-law between the flare index and the maximum umbral area

Electrochemical detectors prepared by electroless deposition for microfabricated electrophoresis chips

Microfabricated capillary electrophoresis (CE) chips with integrated electrochemical detection have been developed on glass substrates. An electroless deposition procedure was used to deposit a gold film directly onto the capillary outlet to provide high-sensitivity electrochemical detection for catechol and several nitroaromatic explosives. Scanning electron microscopy revealed that the electroless gold film contains nanoscopic gold aggregates (100 12150 nm) with an average thickness of 79 nm. The electroless deposition procedure can be easily and routinely performed in any wet-chemistry laboratory, and electroless gold can be deposited onto complex and internal surfaces. Intimate coupling of electrochemical detection and CE chips obviates the need for a coupling mechanism or tedious alignment procedures. With nitroaromatic compounds as a working model, microchip capillary electrophoresis equipped with electroless gold has proven to provide high sensitivity and fast response times for sensor applications. The CE microchip system was capable of separation and determination of explosive compounds including TNT in less than 130 s with detection limits ranging from 24 to 36 \u3bcg/L, i.e., 4-fold enhancements in detection efficiency in comparison to thick-film technology.NRC publication: Ye