Search results for "shell"
showing 10 items of 748 documents
Superheavy element flerovium (element 114) is a volatile metal.
2014
The electron shell structure of superheavy elements, i.e., elements with atomic number Z ≥ 104, is influenced by strong relativistic effects caused by the high Z. Early atomic calculations on element 112 (copernicium, Cn) and element 114 (flerovium, Fl) having closed and quasi-closed electron shell configurations of 6d(10)7s(2) and 6d(10)7s(2)7p1/2(2), respectively, predicted them to be noble-gas-like due to very strong relativistic effects on the 7s and 7p1/2 valence orbitals. Recent fully relativistic calculations studying Cn and Fl in different environments suggest them to be less reactive compared to their lighter homologues in the groups, but still exhibiting a metallic character. Expe…
First Observation of the Unbound NucleusNe15
2014
We report on the first observation of the unbound proton-rich nucleus Ne-15. Its ground state and first excited state were populated in two-neutron knockout reactions from a beam of 500 MeV/u Ne-17. The Ne-15 ground state is found to be unbound by 2.522(66) MeV. The decay proceeds directly to O-13 with simultaneous two-proton emission. No evidence for sequential decay via the energetically allowed 2(-) and 1(-) states in F-14 is observed. The Ne-15 ground state is shown to have a strong configuration with two protons in the (sd) shell around O-13 with a 63(5)% (1s(1/2))(2) component.
Analysis of the Electronic Structure of Non-Spherical Ligand-Protected Metal Nanoclusters : The Case of a Box-Like Ag67
2017
In this work we introduce a new strategy to investigate the electronic shell structure of ligand-protected metal nanoclusters of polyhedral core shape. The central idea is to identify the symmetry of the Kohn–Sham molecular orbitals of an atomistic structure based on their projection onto the electronic states of a jellium system with a similar shape of the background charge density. Herein, we study the connection between a reduced atomistic model of the recently reported box-like [Ag67(SR)32(PR3)8]3+ nanocluster and a jellium box consisting of 32 free electrons. With this approach, we determine the symmetry of electronic states of the metal core and identify those that are involved in the…
Application of the image processing methods for analysis of two-phase flow in turbomachinery
2007
The aim of this research is an application of digital image analysis for working out the method, which will allow to evaluate irregularity rate of two-phase flow across various geometry of tube bundle in aspect of the shell - and - tube heat exchanger optimization. Visualization of liquid flow in the shell — side enables an analysis of flow parameters by the use of image processing and analysis methods.
Lifetime measurements in Ti52,54 to study shell evolution toward N=32
2019
Lifetimes of the excited states in the neutron-rich Ti-52,Ti-54 nuclei, produced in a multinucleon-transfer reaction, were measured by employing the Cologne plunger device and the recoil-distance D ...
Shipping noise affecting immune responses of European spiny lobster (Palinuruselephas)
2015
Marine crustaceans are influenced by numerous environmental factors. Environmental stress from pollutants seems to affect their metabolism, growth, moulting, survival, and immune defence. Recently, it has become clear that there is an impact of the global increase in sea noise levels due to shipping traffic on crustacean welfare. Considering the ecological and commercial importance of the European spiny lobster (Palinurus elephas (Fabricius, 1787)) in most parts of the Mediterranean coastal area, in the present study we investigated whether shipping noise pollution contribute to changing the immune parameters of stress in the European spiny lobster. The animals were exposed to a mix of nois…
Leach-Proof Sol–Gel Microcapsules as Curing Agents for One-Pot Thermosetting Resins
2013
The sol-gel microencapsulation of free-radical initiator benzoyl peroxide in sol-gel methyl-modified silica microcapsules of core/shell geometry allows curing of acrylate-based polyurethane and polyester resin formulations sprayed from a pressurized can without the need to compartmentalize reactants from the initiator to cross-link. These results open the route to widespread application of sol-gel microcapsules to efficiently cure polymer and composite mixtures that are widely used as functional coatings, molding compounds, adhesives, and sealants.
Hybrid Gold/Silica/Quantum-Dots supramolecular-nanostructures encapsulated in polymeric micelles as potential theranostic tool for targeted cancer th…
2018
Abstract Efficient theranostic tools are today more and more frequently represented by the nano-sized systems. In this paper, polymeric micelles were produced and exploited to encapsulate both an antitumor drug (Doxorubicin) and gold core–shell quantum dots nanoparticles (Au-SiO2/QDs). α,β-poly(N-hydroxyethyl)- dl -aspartamide (PHEA) was functionalized with lipoic acid (LA), polyethylenglycol (PEG), and folic acid (FA) pendant moieties to obtain a synthetic derivative (PHEA-LA-PEG-FA) able to self assemble in aqueous medium giving rise to the formation of polymeric micelles exposing on their surface both targeting groups (FA) and hydrophilic chains (PEG). The drug carrying ability of PHEA-L…
New research at Riņņukalns, a Neolithic freshwater shell midden in northern Latvia
2014
The prehistoric shell middens of Atlantic Europe consist of marine molluscs, but the eastern Baltic did not have exploitable marine species. Here the sole recorded shell midden, at Riņņukalns in Latvia, is on an inland lake and is formed of massive dumps of freshwater shells. Recent excavations indicate that they are the product of a small number of seasonal events during the later fourth millennium BC. The thickness of the shell deposits suggests that this was a special multi-purpose residential site visited for seasonal aggregations by pottery-using hunter-gatherer communities on the northern margin of Neolithic Europe.
Eggshell types and their evolutionary correlation with life-history strategies in squamates
2015
The eggshell is an important physiological structure for the embryo. It enables gas exchange, physical protection and is a calcium reserve. Most squamates (lizards, snakes, worm lizards) lay parchment-shelled eggs, whereas only some gekkotan species, a subgroup of lizards, have strongly calcified eggshells. In viviparous (live-bearing) squamates the eggshell is reduced or completely missing (hereafter “shell-less”). Recent studies showed that life-history strategies of gekkotan species differ between species with parchment- and rigid-shelled eggshells. Here we test if the three different eggshell types found in the squamates are also associated with different life-history strategies. We fir…