Search results for "CHARGE"

Oxide/water interfaces: how the surface chemistry modifies interfacial water properties

2012

The organization of water at the interface with silica and alumina oxides is analysed using density functional theory-based molecular dynamics simulation (DFT-MD). The interfacial hydrogen bonding is investigated in detail and related to the chemistry of the oxide surfaces by computing the surface charge density and acidity. We find that water molecules hydrogen-bonded to the surface have different orientations depending on the strength of the hydrogen bonds and use this observation to explain the features in the surface vibrational spectra measured by sum frequency generation spectroscopy. In particular, 'ice-like' and 'liquid-like' features in these spectra are interpreted as the result o…

Beyond ideal two-dimensional metals: Edges, vacancies, and polarizabilities

2018

Recent experimental discoveries of graphene-stabilized patches of two-dimensional (2D) metals have motivated also their computational studies. However, so far the studies have been restricted to ideal and infinite 2D metallic monolayers, which is insufficient because in reality the properties of such metallic patches are governed by microstructures pervaded by edges, defects, and several types of perturbations. Here we use density-functional theory to calculate edge and vacancy formation energies of hexagonal and square lattices of 45 elemental 2D metals. We find that the edge and vacancy formation energies are strongly correlated and decrease with increasing Wigner-Seitz radii, analogously…

Incorporation of the bacterial reaction centre into dendrimersomes

2012

For the first time the ability of the first generation dendrimer belonging to the family of polyester-benzylether, (3,5)12G1-PE-BMPA-(OH)4, to form dendrimersomes is presented together with their capability to reconstitute the integral membrane protein complex called Reaction Centre (RC) purified from the photosynthetic bacterium Rhodobacter sphaeroides. Size, polydispersity and time stability of the empty and protein containing dendrimersomes are presented together with the photochemical activity of the guest protein. The RC presence appears to strongly enhance the self-assembly properties of the Janus dendrimer, leading to the formation of proteo-dendrimersomes showing a photochemical act…

Sensitivity Analysis Of Multi-Electrode Arrays For Characterizing The Non-Saturated Zone In Groundwater Vulnerability Assessment

2009

The near-surface environment acts as a filter and buffer for contaminants introduced from the surface by anthropogenic activities. For this reason there is a great need to improve our understanding of the shallow subsurface taking into account the increasing demand for vulnerability maps which illustrates the exposure of aquifers against pollution. These maps are designed to show areas of greatest potential for groundwater contamination on the basis of local subsurface conditions. A shallow, unconfined sand-and-gravel aquifer is highly vulnerable to pollutants because rapid recharge gives little time to contaminants to degrade naturally or be adsorbed before reaching the aquifer. Conversely…

Variation of the Fermi level and the electrostatic force of a metallic nanoparticle upon colliding with an electrode.

2017

When a metallic nanoparticle (NP) comes in close contact with an electrode, its Fermi level equilibrates with that of the electrode if their separation is less than the cut-off distance for electron tunnelling. In the absence of chemical reactions in solution, the charge on the metallic nanoparticle is constant outside this range before or after the collision. However, the double layer capacitances of both the electrode and the NP are influenced by each other, varying as the function of distance. Because the charge on the nanoparticle is constant, the outer potential of the metallic NP and hence its Fermi level varies as the capacitance changes. This effect is more pronounced for small part…

Field Testing of a Simple Flume (SMBF) for Flow Measurement in Open Channels

2008

In this paper the stage–discharge relationship of a new flume named SMBF (Samani, Magallanex, Baiamonte, Ferro), originally proposed by Samani and Magallanez and tested by Baiamonte and Ferro, for measuring flow discharge in open channels is reviewed. The flume is obtained inserting two semicylinders in a rectangular cross section. The results of some experimental runs carried out using horizontal flumes characterized by different values of the contraction ratio (ranging from 0.17 to 0.81) are used for determining the two coefficients of the power stage–discharge equation. The stage–discharge equation is tested using flow measurements carried out in the period between December 2004 and Marc…

Neutrino energy reconstruction and the shape of the charged current quasielastic-like total cross section

2012

We show that because of the multinucleon mechanism effects, the algorithm used to reconstruct the neutrino energy is not adequate when dealing with quasielastic-like events, and a distortion of the total flux-unfolded cross-section shape is produced. This amounts to a redistribution of strength from high to low energies, which gives rise to a sizable excess (deficit) of low (high) energy neutrinos. This distortion of the shape leads to a good description of the MiniBooNE unfolded charged current quasielastic-like cross sections published by A. A. Aguilar-Arevalo et al. [(MiniBooNE Collaboration), Phys. Rev. D 81, 092005 (2010)]. However, these changes in the shape are artifacts of the unfol…

Enhanced power-conversion efficiency in organic solar cells incorporating polymeric compatibilizers

2018

Measurement of the Effective Weak Mixing Angle inpp¯→Z/γ*→e+e−Events

2015

We present a measurement of the fundamental parameter of the standard model, the weak mixing angle, in $p\bar{p}\rightarrow Z/\gamma^{*}\rightarrow e^{+}e^{-}$ events at a center of mass energy of 1.96 TeV, using data corresponding to 9.7 fb$^{-1}$ of integrated luminosity collected by the D0 detector at the Fermilab Tevatron. The effective weak mixing angle is extracted from the forward-backward charge asymmetry as a function of the invariant mass around the Z boson pole. The measured value of $\sin^2\theta_{\text{eff}}^{\text{$\ell$}}=0.23146 \pm 0.00047$ is the most precise measurement from light quark interactions to date, with a precision close to the best LEP and SLD results.

Study Regarding Process of the Electrical Discharge Machining with Magnetic Activation of the Welded Joints of some Materials High Alloy Steel

2021

The scientific paper presents an extensive research on modeling and optimizing the technological parameters of the process for processing by processing electric discharges with massive electrode with and without magnetic activation. Scientific research is based on real data collected from the process of electrical discharges performed on various samples extracted from areas of welded joints of metal components made of high alloy steel. The processing of experimental data was performed both classically and actively, especially the method of the central factorial experiment composed of orthogonal and rotary. The process parameters that were initially modeled and subsequently optimized were ba…