4,031 research outputs found
Attempting to estimate the influence of wildfires on water levels of Alluvial and Dakota Aquifers in Western Kansas
Wildfires are prevalent events in many areas throughout the world, and this study specifically focuses on wildfires in Western Kansas. The aim of this study is to determine relationships between the landscape, the Alluvial and Dakota Aquifers, and five wildfires to determine possible relationships between these wildfires and groundwater levels. Ideally, water levels from wells within and outside wildfires would be utilized; however, due to the limited number of wells with actual water level measurements in this region, remote sensing imagery coupled with land cover, soil distribution, and soil moisture maps will be utilized to estimate the contribution of wildfires to water level changes. Since the direct groundwater level changes are not able to be determined, external parameters and proxies will need to be used and compared to other regions of the Alluvial and Dakota Aquifers with adequate well data
Mechanism of Reductive Elimination of Methyl Iodide from a Novel Gold(III)−Monomethyl Complex
Oxidation of (Idipp)AuMe (Idipp = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) with I_2 gives a monomethyl Au(III) complex, (Idipp)AuI_2Me, which decomposes cleanly to MeI and (Idipp)AuI. Kinetics experiments show that this transformation occurs primarily via three-coordinate, cationic [(Idipp)AuIMe]^+, which undergoes intramolecular reductive elimination rather than nucleophilic attack by external I^−
Evaluation of the Theoretical Uncertainties in the W to Lepton and Neutrino Cross Sections at the LHC
We study the sources of systematic errors in the measurement of the W to
lepton and neutrino cross-sections at the LHC. We consider the systematic
errors in both the total cross-section and acceptance for anticipated
experimental cuts. We include the best available analysis of QCD effects at
NNLO in assessing the effect of higher order corrections and PDF and scale
uncertainties on the theoretical acceptance. In addition, we evaluate the error
due to missing NLO electroweak corrections and propose which MC generators and
computational schemes should be implemented to best simulate the events.Comment: 33 pages, 109 eps figures, uses JHEP3.cls, rotating.sty Version 2
corrects an error in Table 1, adds some references, and updates an author
addres
Competitive Activation of a Methyl C−H Bond of Dimethylformamide at an Iridium Center
During the synthesis of [AsPh_4][Ir(CO)_2I_3Me] by refluxing IrCl_3·3H_2O in DMF (DMF = dimethylformamide) in the presence of aqueous HCl, followed by sequential treatment with [AsPh_4]Cl, NaI, and methyl iodide and finally recrystallization from methylene chloride/pentane, three crystalline byproducts were obtained: [AsPh4]_2[Ir(CO)I_5], [AsPh_4]_2[trans-Ir(CO)I_4Cl], and [AsPh_4][Ir(CO)(κ^2O,C-CH_2NMeCHO)Cl_2I]. The last of these, whose structure (along with the others) was determined by X-ray diffraction, results from activation of a methyl C−H bond of dimethylformamide, rather than the normally much more reactive aldehydic C−H bond
An Overview of Space Power Systems for NASA Missions
Power is a critical commodity for all engineering efforts and is especially challenging in the aerospace field. This paper will provide a broad brush overview of some of the immediate and important challenges to NASA missions in the field of aerospace power, for generation, energy conversion, distribution, and storage. NASA s newest vehicles which are currently in the design phase will have power systems that will be developed from current technology, but will have the challenges of being light-weight, energy-efficient, and space-qualified. Future lunar and Mars "outposts" will need high power generation units for life support and energy-intensive exploration efforts. An overview of the progress in concepts for power systems and the status of the required technologies are discussed
Urban sediment transport through an established vegetated swale:Long term treatment efficiencies and deposition
Vegetated swales are an accepted and commonly implemented sustainable urban drainage system in the built urban environment. Laboratory and field research has defined the effectiveness of a vegetated swale in sediment detention during a single rainfall-runoff event. Event mean concentrations of suspended and bed load sediment have been calculated using current best analytical practice, providing single runoff event specific sediment conveyance volumes through the swale. However, mass and volume of sediment build up within a swale over time is not yet well defined. This paper presents an effective field sediment tracing methodology and analysis that determines the quantity of sediment deposited within a swale during initial and successive runoff events. The use of the first order decay rate constant, k, as an effective pollutant treatment parameter is considered in detail. Through monitoring tagged sediment deposition within the swale, the quantity of sediment that is re-suspended, conveyed, re-deposited or transported out of the swale as a result of multiple runoff events is illustrated. Sediment is found to continue moving through the vegetated swale after initial deposition, with ongoing discharge resulting from resuspension and conveyance during subsequent runoff events. The majority of sediment initially deposited within a swale is not detained long term or throughout its design life of the swale
Taking Informed Action in Challenging Times: Helping Community Foundations during Economic Downturn
Following up on CF Insights' November 2008 report "Making Informed Decisions in Uncertain Times", this report is aimed at helping community foundations take informed action in relation to their operating models and community activities in reaction to the economic slump. The findings are based on quantitative and qualitative research conducted with 95 community foundations during the spring of 2009. The research findings overall underscore that the field has been able to "make lemonade" from the crisis. In light of tepid expectations for assets and gifts for the rest of 2009, community foundations are being creative and thoughtful in how they allocate precious resources andstep up their community leadership.
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