Children as experiencers: increasing engagement, participation and inclusion for young children in the museum

This research aimed to evaluate young children’s engagement, participation and inclusion within a city museum by utilising observations and semi structured interviews with children and families. Both groups requested more interactive exhibits, sensory experiences, making and doing activities and role play opportunities. In this article, we argue for increased visibility of children’s ‘intangible heritage’(Brookshaw, 2016) and opportunities for responding which make links with children’s lives contemporarily. We further argue that museums should view children as experiencers rather than learners

Establishing the baseline in groundwater chemistry in connection with shale-gas exploration: Vale of Pickering, UK

The baseline chemistry of groundwater from two aquifers in the Vale of Pickering, North Yorkshire, has been investigated ahead of a proposal to explore for shale gas, planning permission for which has recently been granted. Groundwater in a shallow aquifer including Quaternary and/or Jurassic Kimmeridge Clay deposits shows compositions distinct from a Corallian (Jurassic) Limestone aquifer, reflecting different lithologies and hydrogeological conditions. Corallian groundwaters along the margins of the vale are controlled by reaction with carbonate, with redox conditions varying according to degree of aquifer confinement. Superficial aquifer groundwaters are confined and strongly reducing, with some observed high concentrations of dissolved CH4 (up to 37 mg/L; Feb 2016 data). This appears to be of mixed biogenic-thermogenic origin but further work is needed to determine whether the source includes a deeper hydrocarbon reservoir contributing via fractures, or a shallower source in the Quaternary or Kimmeridge sediments. The data show a shallow aquifer with a high-CH4 baseline which pre-dates any shale-gas activity

Empirical comparison of high gradient achievement for different metals in DC and pulsed mode

For the SwissFEL project, an advanced high gradient low emittance gun is under development. Reliable operation with an electric field, preferably above 125 MV/m at a 4 mm gap, in the presence of an UV laser beam, has to be achieved in a diode configuration in order to minimize the emittance dilution due to space charge effects. In the first phase, a DC breakdown test stand was used to test different metals with different preparation methods at voltages up to 100 kV. In addition high gradient stability tests were also carried out over several days in order to prove reliable spark-free operation with a minimum dark current. In the second phase, electrodes with selected materials were installed in the 250 ns FWHM, 500 kV electron gun and tested for high gradient breakdown and for quantum efficiency using an ultra-violet laser.Comment: 25 pages, 13 figures, 5 tables. Follow up from FEL 2008 conference (Geyongju Korea 2008) New Title in JVST A (2010) : Vacuum breakdown limit and quantum efficiency obtained for various technical metals using DC and pulsed voltage source

XPS and UHV AFM Analysis of the K2CsSb Photocathodes Growth

Next generation light sources, based on Energy Recovery Linac and Free Electron Laser technology will rely on photoinjector based electron sources. Successful operation of such sources requires reliable photocathodes with long operational life, uniform and high quantum efficiency, low thermal emittance and low dark current. The goal of this project is to construct a cathode which meets these requirements. Advances in photocathode research must take a combined effort. The materials have to be analyzed by means of chemical composition, surface structure and these findings have to be correlated to the quantum efficiency and performance in the injector. The presented work focuses on the chemical composition and surface structure of K2CsSb photocathodes. The XPS and AFM measurements were performed at the Center of Functional Nanomaterials at BNL. K2CsSb photocathodes were grown under UHV conditions. The components were adsorbed one at a time and after each growth step the corresponding XPS spectra was taken. During growth the quantum efficiency was recorded. As last step the sample was moved into the AFM without exposure to air to determine the surface roughnes

Shell formation and star formation in superbubble DEM 192

Was star formation in the OB associations, LH 51 and LH 54, triggered by the growth of the superbubble DEM 192? To examine this possibility, we investigate the stellar contents and star formation history, and model the evolution of the shell. H-R diagrams constructed from UBV photometry and spectral classifications indicate highly coeval star formation, with the entire massive star population having an age of ~< 2-3 Myr. However, LH 54 is constrained to an age of ~3 Myr by the presence of a WR star, and the IMF for LH 51 suggests a lower-mass limit implying an age of 1-2 Myr. There is no evidence of an earlier stellar population to create the superbubble, but the modeled shell kinematics are consistent with an origin due to the strongest stellar winds of LH 54. It might therefore be possible that LH 54 created the superbubble, which in turn may have triggered the creation of LH 51. Within the errors, the spatial distribution of stellar masses and IMF appear uniform within the associations. We reinvestigate the estimates for stellar wind power L_w(t), during the H-burning phase, and note that revised mass-loss rates yield a significantly different form for L_w(t), and may affect stellar evolution timescales. We also model superbubble expansion into an ambient medium with a sudden, discontinuous drop in density, and find that this can easily reproduce the anomalously high shell expansion velocities seen in many superbubbles.Comment: 18 pages, 12 figures, AASTeX; Figure 1 bitmapped. Accepted to AJ. Table of Contents and preprint, including hi-resolution version of Figure 1, available at: http://www.ast.cam.ac.uk/~oey/oeypubs.htm

Influence of Growth Method on K3Sb Photocathode Structure and Performance

Future high brightness photoelectron sources delivering gt;100 mA average current call for a new generation of photocathodes. Materials which qualify for this purpose should exhibit low intrinsic emittance, long lifetime and high quantum efficiency at photon energies in the visible range of the spectrum to relax drive laser requirements. A combination of material science techniques are used to determine the influence of the growth parameters on structure and performance of photocathode materials . In situ XRR, XRD and GiSAXS measurements were performed at the synchrotron radiation sources, NSLS and CHESS. The growth of K3Sb, a precursor material of one of the prime candidates CsK2Sb, was studied intensively to optimize this intermediate growth step in terms of quantum efficiency and roughness. Three methods, a layer by layer type and a super lattice type were examined. K3Sb exists in two crystallographic phases, namely cubic and hexagonal. The cubic phase exhibits a higher quantum efficiency at 532 nm than the hexagonal phase and transforms more easily into CsK2Sb, tuning this phase is believed to be one of the key parameters in the CsK2Sb growt

The construction and characterization of MgO transmission dynodes

In this work we demonstrate that ultra-thin (5 and 15 nm) MgO transmission dynodes (tynodes) with sufficient high transmission electron yield (TEY) can be constructed. These tynodes act as electron amplification stages in a novel vacuum electron multiplier: the Timed Photon Counter (TiPC). The ultra-thin membranes with a diameter of 30 {\mu}m are arranged in a square 64-by-64-array. The TEY was determined with a scanning electron microscope (SEM) using primary electrons with primary energies of 0.75 - 5 keV. The method allow us to make a TEY map of the surface while simultaneously imaging the surface. The TEY of individual membranes can be extracted from the TEY map. An averaged maximum TEY of 4.6 +/- 0.2 was achieved by using 1.35 keV primary electrons on a TiN/MgO bi-layer membrane with a layer thickness of 2 and 5 nm, respectively. The TiN/MgO membrane with a layer thickness of 2 and 15 nm, respectively, has a maximum TEY of 3.3 +/- 0.1 (2.35 keV). Furthermore, the effect of the electric field strength on transmission (secondary) electron emission was investigated by placing the emission surface of a tynode in close proximity to a planar collector. By increasing the electric potential between the tynode and the collector, from -50 V to -100 V, the averaged maximum TEY improved from 4.6 +/- 0.2 to 5.0 +/- 0.3 at a primary energy of 1.35 keV with an upper limit of 5.5 on one of the membranes

Determining intended evidence relations in natural language arguments

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72555/1/j.1467-8640.1991.tb00386.x.pd