28 research outputs found
Toward an experimental proof of superhydrophobicity enhanced by quantum fluctuations freezing on a broadband-absorber metamaterial
Previous theoretical works suggested that superhydrophobicity could be
enhanced through partial inhibition of the quantum vacuum modes at the surface
of a broadband-absorber metamaterial which acts in the extreme ultraviolet
frequency domain. This effect would then compete with the classical
Cassie-Baxter interpretation of superhydrophobicity. In this article, we first
theoretically establish the expected phenomenological features related to such
a kind of "quantum" superhydrophobicity. Then, relying on this theoretical
framework, we experimentally study patterned silicon surfaces on which
organosilane molecules were grafted, all the coated surfaces having similar
characteristic pattern sizes but different profiles. Some of these surfaces can
indeed freeze quantum photon modes while others cannot. While the latter ones
allow hydrophobicity, only the former ones allow for superhydrophobicity. We
believe these results lay the groundwork for further complete assessment of
superhydrophobicity induced by quantum fluctuations freezing.Comment: 10 pages, 5 figures, final version, accepted for publication in
Journal of Applied Physic
Evidence of Novel Quasiparticles in a Strongly Interacting Two-Dimensional Electron System: Giant Thermopower and Metallic Behaviour
We report thermopower () and electrical resistivity ()
measurements in low-density (10 m), mesoscopic two-dimensional
electron systems (2DESs) in GaAs/AlGaAs heterostructures at sub-Kelvin
temperatures. We observe at temperatures 0.7 K a linearly growing
as a function of temperature indicating metal-like behaviour. Interestingly
this metallicity is not Drude-like, showing several unusual characteristics: i)
the magnitude of exceeds the Mott prediction valid for non-interacting
metallic 2DESs at similar carrier densities by over two orders of magnitude;
and ii) in this regime is two orders of magnitude greater than
the quantum of resistance and shows very little temperature-dependence.
We provide evidence suggesting that these observations arise due to the
formation of novel quasiparticles in the 2DES that are not electron-like.
Finally, and show an intriguing decoupling in their
density-dependence, the latter showing striking oscillations and even sign
changes that are completely absent in the resistivity.Comment: QFS2012 Conference proceedings, Journal of Low Temperature Physics,
accepted (figure and discussion added upon referee suggestions
Variable use of amiodarone is associated with a greater risk of recurrence of atrial fibrillation in the critically ill
Results of the Multicenter RENEWALR 3 AVT Clinical Study of Cardiac Resynchronization Defibrillator Therapy in Patients with Paroxysmal Atrial Fibrillation
Effect of a gas-gas-heater on H2SO4 aerosol formation: implications for mist formation in amine based carbon capture
This study is to our knowledge the first to describe the effect of a Gas-Gas Heater (GGH) of a coal fired power plant's has on (i) the H2SO4 concentration and (ii) the particle/aerosol number concentration and particle size distribution present in the flue gas. In the absence of a GGH, homogenous nucleation takes places inside the Wet Flue Gas Desulphurisation (WFGD) converting the gaseous H2SO4 into aerosol H2SO4. This leads to a high aerosol number concentration behind the WFGD with 80% of the aerosols being smaller than 0.02 μm. This implies that an amine based carbon capture (CC) installation treating this flue gas can suffer from amine mist formation due to the high amount of available nuclei (i.e., H2SO4 aerosols) resulting in high amine emissions. In contrast, in the presence of a GGH not only 70% of the H2SO4 is removed from the flue gas (measured at the Nijmegen powerplant), but also homogenous nucleation in the WFGD is prevented resulting in low particle number concentrations. The flue gas leaving the GGH will not create any mist formation issues in an amine based CC installation due to the low amount of nuclei present in the flue gas. It is not the reduction in H2SO4 concentration by 70% inside the GGH as such that prevents mist formation but absence of H2SO4 in its aerosol form. These results are most likely quite widely transformable to other power plants that burn low sulfur coal i.e., around 0.7 weight%. This information will serve future pilot and demo CC installation around the world; in particular when retrofitted on power plants that have a GGH
Identifying Design Requirements of a User-Centered Research Data Management System
Research data repositories perform many useful functions, the key ones being the storage of research datasets, and making the same discoverable for potential reuse. Over the years, various criteria for assessing the user-centeredness of information systems have been developed and standards have gradually been improved. However, there has been less development in case of re-search data management (RDM) systems. By means of a combination of user-focused research methods viz. questionnaire surveys, face-to-face interviews, a systematic appraisal of existing services and a technical experiment, we have sought to understand the meaning of user-centeredness pertaining to research data repositories, and identify some key indicators of it. We have furthermore translated our findings into design requirements based on which we propose to develop and test a prototype of a user-centered RDM system. This paper reports on how we identified the design requirements that would make the RDM systems more user-centered