The distinction of rock types on the basis of their mass spectra, with special reference to lunar-surface applications

It is shown that the rock types most commonly expected to be encountered on the lunar surface can for the most part be readily distinguished, chemically, by plotting their relative concentrations of Fe, Mg, and Al on a ternary variation diagram. The necessary data for characterizing as unknown as to rock type can be quite easily extracted from complete or partial mass spectra such as may be obtained by means of a robot mass spectrometer on the lunar surface. For most compositions, determination of only two nuclide or element rations will characterize the sample. Fo others, the determination of one additional ratio or comparison with a few standard spectra previously obtained in the laboratory may be necessary to clarify the unknown in terms of the chemistry of the terrestrial or meteoritic equivalents. No quantitative assay of element concentrations is necessary for such a first classification

Carbon isotope fractionation in the system CO2/gas/-CO2/aqueous/-HCO3-/aqueous/

Carbon isotope fractionation between gaseous carbon dioxide and aqueous bicarbonat

Keeping Fountain Grass out of the Mojave Desert

Fountain Grass (Pennisetum setaceum) is an escaped ornamental perennial bunchgrass from Africa that has invaded parts of Hawaii and the Sonoran Desert. It is adapted to fire and increases hazardous fuels causing wildfires in areas that may not have historically occurred. It was detected in the late 1990’s within the Mojave Desert at Joshua Tree NP and along the Colorado River corridor on the shores of Lake Mohave. The extent of these populations was limited and a rapid response was necessary to keep it from spreading out of control. If no action is taken then fountain grass would spread by windblown seed similar to the way tamarisk has infested the region. The National Park Service began controlling these recently detected populations in 2001. Control is also occurring on adjacent US Fish and Wildlife Refuges by the NPS Lake Mead EPMT through partnerships agreements. Nevada designated fountain grass on the State Noxious Weed List in 2002 and one the largest commercial nurseries in the state voluntarily withdrew it from sales prior to listing. Populations of this weedy grass have dramatically declined due to successful control actions

Process planning and control of functionally graded parts using freeze-form extrusion fabrication

Freeze-form Extrusion Fabrication (FEF) is an additive manufacturing technology that is capable of fabricating complex three-dimensional parts. FEF works by depositing an aqueous-based colloidal ceramic or metal paste in a layer-by-layer fashion below the freezing point of the aqueous medium as to rapidly freeze the paste. The FEF machine in the present study is equipped with three syringes and is capable of mixing each paste in a desired composition ratio by using an inline static mixer. Compensation for the transport delay caused by the static mixer is necessary; therefore, an algorithm was developed to apply a one-dimensional (1D) composition gradient to monolithic parts, adjusting the plunger velocities to account for the transport delay. Control of extrusion-based additive manufacturing techniques is difficult due to the uncertainties of the paste properties such as entrapped air bubbles, inhomogeneity, and inconsistency of the paste rheology from batch to batch. Other challenges are present such as starting and stopping extrusion on demand (EOD) and steady-state velocity control of a coupled triple extruder system. These issues have been addressed with the development and implementation of a hybrid extrusion force-velocity controller --Abstract, page iv

Two-site DNA Minor Groove Binding Compounds

DNA minor groove binding compounds have had limited therapeutic uses, in part due to problems with sequence specificity. A two-site model has been developed to enhance specificity, in which compounds bind to two short AT sites separated by one or two GC base pairs. Using thermal melting, heterocyclic dications with this capability were tested with various oligonucleotides for binding affinity and specificity. Compounds of interest were further probed using circular dichroism, mass spectrometry, biosensor-SPR, and molecular modeling. Several compounds were found to “jump” a GC base pair, binding to AT sites in the minor groove of DNA with a two-site recognition mode. One compound was also found to recognize a single intervening GC base pair. Compounds with terminal, non-polar amidine extensions were found to have increased DNA binding compared to analogs with terminal amidines. This unique, two-site DNA recognition mode offers novel design principles to recognize entirely new DNA motifs

Armstrong\u27s Axioms and Navigation Strategies

The paper investigates navigability with imperfect information. It shows that the properties of navigability with perfect recall are exactly those captured by Armstrong\u27s axioms from database theory. If the assumption of perfect recall is omitted, then Armstrong\u27s transitivity axiom is not valid, but it can be replaced by a weaker principle. The main technical results are soundness and completeness theorems for the logical systems describing properties of navigability with and without perfect recall

Athel (Tamarix aphylla) and Athel hybrid (Tamarix aphyllaX Tamarix ramosissima)Establishment and Control at Lake Mead National Recreation Area

Athel is a large evergreen ornamental tree that has been planted throughout the Southwest since the 1950’s. Athel was considered benign because it was thought to produce non-viable seed unlike its invasive relative, tamarisk. However, athel began establishing in the wild from seed on Lake Mead in 1983. Lake Mead NRA has been actively controlling athel since November 2004 along the high water mark of Lake Mead shoreline (439 miles) to prevent it from spreading throughout the Colorado River Drainage. The NPS contracts Nevada Conservation Corp crews and the Lake Mead Exotic Plant Management Team to implement the control efforts of athel and the hybrid. Since 2004 Lake Mead NRA has controlled 72,156 athel and 11,749 hybrids. Control methods have been effective and follow up monitoring and retreatment is planned during the 2009 field season. Based on observations at Lake Mead NRA, the invasive potential of athel is high, particularly in light of its hybridization potential with tamarisk thus creating a new noxious weed. Natural resource land managers should be vigilant in monitoring current athel populations to ensure they do not become invasive or hybridize with tamarisk