A description of the DOE Radionuclide Aerosol Sampler/Analyzer for the Comprehensive Test Ban Treaty

Radionuclide monitoring, though slower than vibrational methods of explosion detection, provides a basic and certain component of Comprehensive Test Ban treaty (CTBT) verification. Measurement of aerosol radioactive debris, specifically a suite of short-lived fission products, gives high confidence that a nuclear weapon has been detonated in or vented to the atmosphere. The variable nature of wind-borne transport of the debris requires that many monitoring stations cover the globe to insure a high degree of confidence that tests which vent to the atmosphere will be detected within a reasonable time period. To fulfill the CTBT aerosol measurement requirements, a system has been developed at PNNL to automatically collect and measure radioactive aerosol debris, then communicate spectral data to a central data center. This development has proceeded through several design iterations which began with sufficient measurement capability (<30 μBq/m^{3 140}Ba) and resulted in a system with a minimal footprint (1 m×2 m), minimal power requirement (1600W), and support of network infrastructure needs. The Mark IV prototype (Fig. 1) is currently the subject of an Air Force procurement with private industry to partially fulfill US treaty obligations under the CTBT. It is planned that the system will be available for purchase from a manufacturer in late 1997.     

Exploring Graduate‐Level Scientists' Participation in a Sustained K‐12 Teaching Collaboration

To increase scientific literacy in America, the National Science Foundation has implemented the Graduate Teaching Fellows in K‐12 Initiative (GK‐12). In these programs graduate level scientists, known as Graduate Teaching Fellows (GTFs), act as resources for science teachers (Partner Teachers). This research examines the influence of participation in this program on the GTFs involved in one GK‐12 sustained collaboration that emphasizes the codevelopment and co‐implementation of hands‐on, inquiry‐based activities. Qualitative data in the form of interviews and observations were collected from a single cohort of Partner Teachers, GTFs, and the academic advisors of the GTFs for one academic year. The GTFs identified three benefits they received from working in the GK‐12 program: enhanced understanding of science content, fuller understanding of the complexities of teaching science, and understanding of inquiry‐based science teaching and its value. At the same time the GTFs experienced tensions related to differing views of science and science teaching held by the GTFs and the Partner Teachers. The GTFs also experienced professional risks in at least two ways due to their involvement in this program. One risk was the result of the time commitment required to be a GTF. The other was the result of what was termed competing foci. Illustrated in this case by the difficulties encountered as GTFs attempted to learn how to teach in a secondary science classroom while still learning to become research scientists.     

A theory for the numerical analysis of compound branching

Zusammenfassung Eine allgemeine Theorie zur numerischen Berechnung eines konservativen Systems mitn Freiheitsgraden undm überlagerten Verzweigungspunkten wird dargestellt. Im Unterschied zu früheren Arbeiten wird kein Diagonalisierungsschema der totalen potentiellen Energie benötigt. Ein Störungsschema wird angegeben, umn–m verallgemeinerte Koordinaten mit Hilfe vonn–m Gleichgewichtsbedingungen zu eliminieren. Anschließend wird ein zweites Störungsschema angegeben, um die Ableitungen der 2 ^m –1 möglichen Äste der Last-Verformungskurven, die im kritischen Punkt entspringen, zu bestimmen. Anschließend wird die Theorie auf zweifache kritische Punkte angewendet, die beim Ausbeulen der durch gleichmäßigen Außendruck belasteten vollständigen Kugelschale auftreten.     

Synthesis of the ladybug defensive agents (±)-hippodamine, (±)-convergine, (±)-hippocasine and (±)-hippocasine oxide

The total syntheses of the ladybug defensive agents (±)-hippodamine, (±)-convergine, (±)-hippocasine, and (±)-hippocasine oxide are described starting from perhydroboraphenalene.     

Preliminary investigation of fungal bioprocessing of wheat straw for production of straw-thermoplastic composites

Straw utilization for composites is limited by poor resin and polymer penetration, and excessive resin consumption owing to the straw cuticle, fines, and lignin-hemicellulose matrix. White-rot fungi degrade these components of straw and could, therefore, potentially be used to improve resin penetration and resin binding without the use of physical or chemical pretreatments. Although long treatment times and large footprints the limit use of fungal treatments on a large scale, distributed fungal pretreatments could alleviate land requirements. In this article, we present progress toward the development of a passive fungal straw upgrading system utilizing whiterot fungi.