197 research outputs found

    Mid-Scale Instrumentation: Regional Facilities to Address Grand Challenges in Chemistry

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    A regional workshop sponsored by the National Science Foundation, Arlington, Virginia, September 29-30, 2016. To determine what needs and opportunities might exist for mid-scale instrumentation (MSI), two workshops were held in fall of 2016 to explore opportunities within the discipline that could be provided by such investment. One workshop was convened to explore the need for co-localization of existing instrumentation at a regional or cyber-enabled facilities (addressed in this report, “Mid-Scale Instrumentation: Regional Facilities to Address Grand Challenges in Chemistry”). In this report, we identify different areas where investment in such MSI facilities would be highly beneficial. These appear as six “grand challenges” that can be summarized here as follows: 1. Structure and dynamics at interfaces 2. Highly parallel chemical synthesis and characterization 3. Transient intermediates 4. New science arising from the characterization of heterogeneous mixtures 5. Multi-scale dynamics of complex systems: integrating transport with reaction 6. Structure-function relationship in disordered and/or heterogeneous system

    Finding a third archetypal technical system in architectural phenomenology

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    Within the scope of phenomenology and in order to understand architecture, the role of the technical system is as important as those of the purpose of the building or its form. Mass construction and skeletal construction relate to the architectural theory concepts stereotomy and tectonics respectively, which are suitable for describing the fundamental structural and constructive form of architecture. These two systems became established as man built his first shelters and, so far, represented opposite sides of the building industry’s possibilities. The development of new construction techniques and the relationship between research and technology have a great impact on architecture, although new processing methods and materials may not necessarily cause genuine tectonic changes. The technical dimension of architecture is analysed in this work describing how technical elements are built from materials, and then organised in systems. First, the paper examines the division of technical systems in two categories (massive systems and skeletal systems); then it studies timber’s modern production technologies and subsequently the paper critically analyses how these influence the architectural form. The paper concludes that a third archetypal technical system can be perceived with the assembly of surface elements, joining both the multifunctional aspect of the massive systems and the flexibility of the skeletal systems, this third category being fundamental in phenomenological terms

    Analysis of Electrodeposited Nickel-Iron Alloy Film Composition Using Particle-Induced X-Ray Emission

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    The elemental composition of electrodeposited NiFe thin films was analyzed with particle-induced X-ray emission (PIXE). The thin films were electrodeposited on polycrystalline Au substrates from a 100mM NiSO4, 10 mM FeSO4, 0.5M H3BO3, and 1M Na2SO4 solution. PIXE spectra of these films were analyzed to obtain relative amounts of Ni and Fe as a function of deposition potential and deposition time. The results show that PIXE can measure the total deposited metal in a sample over at least four orders of magnitude with similar fractional uncertainties. The technique is also sensitive enough to observe the variations in alloy composition due to sample nonuniformity or variations in deposition parameters

    Feasibility of isotope harvesting at a projectile fragmentation facility: ⁶⁷Cu

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    The work presented here describes a proof-of-principle experiment for the chemical extraction of (67)Cu from an aqueous beam stop at the National Superconducting Cyclotron Laboratory (NSCL). A 76 MeV/A (67)Cu beam was stopped in water, successfully isolated from the aqueous solution through a series of chemical separations involving a chelating disk and anion exchange chromatography, then bound to NOTA-conjugated Herceptin antibodies, and the bound activity was validated using instant thin-layer chromatography (ITLC). The chemical extraction efficiency was found to be 88 ± 3% and the radiochemical yield was ≥95%. These results show that extraction of radioisotopes from an aqueous projectile-fragment beam dump is a feasible method for obtaining radiochemically pure isotopes

    Total Fluorine Analysis to Screen for PFAS in Personal Care Products

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    A series of commercially available personal care products have been screened for the presence of fluorine, as a surrogate for the presence of per- and polyfluorinated alkyl substances (PFAS). The novel total fluorine method used is Particle-Induced Gamma-ray Emission (PIGE) spectroscopy, which has been previously used in prevalence studies of PFAS in consumer goods such as food packaging and textiles. As in other industries, a significant fraction of personal care products was found to contain large quantities of total fluorine, although because of the presence of some inorganic fluoride compounds used in cosmetics (synthetic mica, for example), it is more difficult to distinguish which products use PFAS. However, an organofluorine analysis was performed as well as traditional LC-MS/MS measurements to identify likely PFAS compounds present. Preliminary data about the two forms of personal care products that are likely to represent significant PFAS exposure risks to the wearer (water-proof mascara and water-proof lip-stick) will be presented.Ope

    Big Physics At Small Places: The Mongol Horde Model Of Undergraduate Research

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    A model for engaging undergraduates in cutting-edge experimental nuclear physics research at a national user facility is discussed.  Methods to involve students and examples of their success are presented

    Alpha Particle Emission from6He + 209Bi

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    In a recent experiment, we have for the first time studied near-barrier and sub-barrier fusion of the exotic Borromean nucleus 6He with 209Bi and found that the sub-barrier fusion of this system is exceptionally enhanced, implying a 20% reduction in the nominal fusion barrier. It was suggested that this striking effect might he due to coupling to positive Q-value neutron transfer channels, leading to neutron flow and consequent neck formation between the projectile and target. The results of a new experiment using the radioactive nuclear beam facility at the University of Notre Dame to measure fast ⍺-particle emission from 6He + 209Bi are discussed. A exceptional1y strong transfer/breakup group was observed at near-barrier and sub-barrier energies; this is very likely to be the doorway state that explains the enhanced sub-barrier fusion. In a recent experiment, we have for the first time studied near-barrier and sub-barrier fusion of the exotic Borromean nucleus 6He with 209Bi and found that the sub-barrier fusion of this system is exceptionally enhanced, implying a 20% reduction in the nominal fusion barrier. It was suggested that this striking effect might he due to coupling to positive Q-value neutron transfer channels, leading to neutron flow and consequent neck formation between the projectile and target. The results of a new experiment using the radioactive nuclear beam facility at the University of Notre Dame to measure fast ⍺-particle emission from 6He + 209Bi are discussed. A exceptional1y strong transfer/breakup group was observed at near-barrier and sub-barrier energies; this is very likely to be the doorway state that explains the enhanced sub-barrier fusion
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