1,145 research outputs found

    Аграрне перенаселення в українських губерніях Російської імперії початку ХХ ст.

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    Sustainable urban development is a critical issue in the Netherlands. The country is densely populated, which causes conflicts between environmental concerns and spatial development. Environmental policy integration is proposed as a way to improve the integration of environmental values into spatial planning with the help of learning processes. This chapter evaluates the extent to which the combination of a map-based touch table and an area-specific environmental profile are of added value to environmental policy integration. The case study is the application of the map-based touch table, called MapTable® for the development of a sustainable neighborhood in the region of Utrecht, the Netherlands. It was found that MapTable® facilitates learning processes by providing a platform for communication among stakeholders from different backgrounds. Nonetheless, it must be ensured that all stakeholders are equally included, and that the process suits the application of a map-based touch table in combination with an area-specific environmental profile

    CHD3 Dissociation on the Kinked Pt(210) Surface: A Comparison of Experiment and Theory

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    To be able to simulate activated heterogeneously catalyzed reactions on the edge and corner sites of nanoparticles, a method for calculating accurate activation barriers for the reactions is required. We have recently demonstrated that a semiempirical specific reaction parameter (SRP) density functional developed to describe CHD3 dissociation on a flat Ni(111) surface is transferable to describing the same reaction on a stepped Pt(211) surface. In the current work, we compare initial sticking coefficients measured using the King and Wells beam reflectivity technique and calculated from ab initio molecular dynamics trajectories using the same SRP functional for CHD3 dissociation on a kinked Pt(210) surface at a temperature of 650 K. The calculated sticking coefficients overestimate those determined experimentally, with an average energy shift between the two curves of 13.6 kJ/mol, which is over a factor of 3 times higher than the 4.2 kJ/mol limit that defines chemical accuracy. This suggests the SRP functional predicts an activation barrier that is too low for the dissociation on the least coordinated kink atom, which is the site of the lowest energy transition state and where most of the dissociation occurs in the calculations.Article / Letter to editorLIC/ES/Theoretical Chemistr

    Forces on a boiling bubble in a developing boundary layer, in microgravity with g-jitter and in terrestrial conditions

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    Terrestrial and microgravity flow boiling experiments were carried out with the same test rig, comprising a locally heated artificial cavity in the center of a channel near the frontal edge of an intrusive glass bubble generator. Bubble shapes were in microgravity generally not far from those of truncated spheres,which permitted the computation of inertial lift and drag from potential flow theory for truncated spheres approximating the actual shape. For these bubbles, inertial lift is counteracted by drag and both forces are of the same order of magnitude as g-jitter. A generalization of the Laplace equation is found which applies to a deforming bubble attached to a plane wall and yields the pressure difference between the hydrostatic pressures in the bubble and at the wall, p. A fully independent way to determine the overpressure p is given by a second Euler-Lagrange equation. Relative differences have been found to be about 5% for both terrestrial and microgravity bubbles. A way is found to determine the sum of the two counteracting major force contributions on a bubble in the direction normal to the wall from a single directly measurable quantity. Good agreement with expectation values for terrestrial bubbles was obtained with the difference in radii of curvature averaged over the liquid-vapor interface, (1/R2 − 1/R1), multiplied with the surface tension coefficient, σ. The new analysis methods of force components presented also permit the accounting for a surface tension gradient along the liquid-vapor interface. No such gradients were found for the present measurements

    Toward detection of electron-hole pair excitation in H-atom collisions with Au(111): Adiabatic molecular dynamics with a semi-empirical full-dimensional potential energy surface.

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    We report an analytic potential energy surface (PES) based on several hundred DFT energies for H interacting with a Au(111) surface. Effective medium theory is used to fit the DFT data, which were obtained for the Au atoms held at their equilibrium positions. This procedure also provides an adequate treatment of the PES for displacements of Au atoms that occur during scattering of H atoms. The fitted PES is compared to DFT energies obtained from ab initio molecular dynamics trajectories. We present molecular dynamics simulations of energy and angle resolved scattering probabilities at five incidence angles at an incidence energy, Ei = 5 eV, and at a surface temperature, TS = 10 K. Simple single bounce trajectories are important at all incidence conditions explored here. Double bounce events also make up a significant fraction of the scattering. A qualitative analysis of the double-bounce events reveals that most occur as collisions of an H-atom with two neighboring surface gold atoms. The energy losses observed are consistent with a simple binary collision model, transferring typically less than 150 meV to the solid per bounce
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