83 research outputs found

    Low-cost, Transportable Hydrogen Fueling Station for Early FCEV Adoption

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    Thousands of public hydrogen fueling stations are needed to support the early Fuel Cell Electric Vehicle (FCEV) market in the U.S.; there are currently 12. The California state government has been the largest investor of the hydrogen fueling infrastructure funding 9 permanent stations currently open to the public with 48 more in development costing anywhere from 1.8M−1.8M-5.5M each. To attract private investors and decrease dependence on government funding, a low-cost, mobile hydrogen dispensing system must be developed. This paper describes a transportable hydrogen fueling station that has been designed for 423,000usingoff−the−shelfcomponents,lessthan23423,000 using off-the-shelf components, less than 23% of the capital cost of current stations. It utilizes liquid hydrogen storage and a novel cryogenic compression system which can be factory built for high volume, rapid production. These stations would be contained in a standard 40’ ISO shipping container to move/expand with demand and dispense hydrogen at a price of 9.62/kg. This paper presents the mechanical design and operation of the fueling station. A complete report including an economic analysis and safety features is available at: http://hydrogencontest.org/pdf/2014/WSU_2014_HEF_CONTEST.pdf

    Large-scale and rapid synthesis of disk-shaped and nano-sized graphene

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    We synthesized disk-shaped and nano-sized graphene (DSNG) though a novel ion-exchange methodology. This new methodology is achieved by constructing metal ion/ion-exchange resin framework. The morphology and size of the graphene can be modulated by changing the mass ratio of the carbon-containing resin to the cobalt-containing precursor. This is the first time to show that the DSNG formed on the granular transition metal substrate. The DSNG gives a high intensity of photoluminescence at near-UV wavelength of 311 nm which may provide a new type of fluorescence for applications in laser devices, ultraviolet detector UV-shielding agent and energy technology. The emission intensity of the DSNG is thirty times higher than that of the commercial large graphene. Our approach for graphene growth is conveniently controllable, easy to scale-up and the DSNG shows superior luminescent properties as compared to conventional large graphene

    Probing the Thermal Deoxygenation of Graphene Oxide using High Resolution In Situ X-Ray based Spectroscopies

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    Despite the recent developments in Graphene Oxide due to its importance as a host precursor of Graphene, the detailed electronic structure and its evolution during the thermal reduction remain largely unknown, hindering its potential applications. We show that a combination of high resolution in situ X-ray photoemission and X-ray absorption spectroscopies offer a powerful approach to monitor the deoxygenation process and comprehensively evaluate the electronic structure of Graphene Oxide thin films at different stages of the thermal reduction process. It is established that the edge plane carboxyl groups are highly unstable, whereas carbonyl groups are more difficult to remove. The results consistently support the formation of phenol groups through reaction of basal plane epoxide groups with adjacent hydroxyl groups at moderate degrees of thermal activation (~400 {\deg}C). The phenol groups are predominant over carbonyl groups and survive even at a temperature of 1000 {\deg}C. For the first time a drastic increase in the density of states (DOS) near the Fermi level at 600 {\deg}C is observed, suggesting a progressive restoration of aromatic structure in the thermally reduced graphene oxideComment: Pagona Papakonstantinou as Corresponding author, E-mail: [email protected]

    Nucleation of chemical vapor deposited silicon nitride on silicon dioxide

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    We have studied the early stages of silicon nitride chemical vapor deposition (CVD) on silicon dioxide using medium energy ion scattering. The growth mode consists of island nucleation followed by coalescence. Similar behavior is observed for films grown using different precursors and reactor environments, indicating that the growth mode is caused by the fundamental nonwetting nature of the nitride/oxide interface under the conditions used for CVD. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69633/2/APPLAB-74-13-1830-1.pd

    An infrared study of H8Si8O12H8Si8O12 cluster adsorption on Si(100) surfaces

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    Motivated by a controversy about the proper interpretation of x-ray photoelectron spectra of Si/SiO2Si/SiO2 interfaces derived from the adsorption of H8Si8O12H8Si8O12 spherosiloxane clusters on Si(100) surfaces, we have studied the adsorption geometry of the H8Si8O12H8Si8O12 clusters on deuterium-passivated and clean Si(100) surfaces by using external reflection infrared spectroscopy. Access to frequencies below 1450 cm−11450cm−1 was made possible through the use of specially prepared Si(100) samples which have a buried metallic CoSi2CoSi2 layer that acts as an internal mirror. A comparison of the infrared spectrum of the clusters on a deuterium-passivated Si(100) surface at 130 K with an infrared spectrum of the clusters in a carbon tetrachloride solution reveals that the clusters are only weakly physisorbed on the D/Si(100) surface and also provides evidence for the purity of the cluster source. We also present infrared spectra of clusters directly chemisorbed on a clean Si(100) surface and show evidence that the clusters are adsorbed on the Si(100) via attachment by one vertex. A complete assignment of the observed vibrational features, for both physisorbed and chemisorbed clusters, has been made based upon comparisons with the results obtained in ab initio calculations using gradient-corrected density functional methods. © 1998 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69818/2/JCPSA6-108-20-8680-1.pd
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