Accurate Ne-heavier rare gas interatomic potentials

International Nuclear Information System (INIS)

Candori, R.; Pirani, F.; Vecchiocattivi, F.

1983-01-01

Accurate interatomic potential curves for Ne-heavier rare gas systems are obtained by a multiproperty analysis. The curves are given via a parametric function which consists of a modified Dunham expansion connected at long range with the van der Waals expansion. The experimental properties considered in the analysis are the differential scattering cross sections at two different collision energies, the integral cross sections in the glory energy range and the second virial coefficients. The transport properties are considered indirectly by using the potential energy values recently obtained by inversion of the transport coefficients. (author)

Genomic and expression analysis of the vanG-like gene cluster of Clostridium difficile.

Science.gov (United States)

Peltier, Johann; Courtin, Pascal; El Meouche, Imane; Catel-Ferreira, Manuella; Chapot-Chartier, Marie-Pierre; Lemée, Ludovic; Pons, Jean-Louis

2013-07-01

Primary antibiotic treatment of Clostridium difficile intestinal diseases requires metronidazole or vancomycin therapy. A cluster of genes homologous to enterococcal glycopeptides resistance vanG genes was found in the genome of C. difficile 630, although this strain remains sensitive to vancomycin. This vanG-like gene cluster was found to consist of five ORFs: the regulatory region consisting of vanR and vanS and the effector region consisting of vanG, vanXY and vanT. We found that 57 out of 83 C. difficile strains, representative of the main lineages of the species, harbour this vanG-like cluster. The cluster is expressed as an operon and, when present, is found at the same genomic location in all strains. The vanG, vanXY and vanT homologues in C. difficile 630 are co-transcribed and expressed to a low level throughout the growth phases in the absence of vancomycin. Conversely, the expression of these genes is strongly induced in the presence of subinhibitory concentrations of vancomycin, indicating that the vanG-like operon is functional at the transcriptional level in C. difficile. Hydrophilic interaction liquid chromatography (HILIC-HPLC) and MS analysis of cytoplasmic peptidoglycan precursors of C. difficile 630 grown without vancomycin revealed the exclusive presence of a UDP-MurNAc-pentapeptide with an alanine at the C terminus. UDP-MurNAc-pentapeptide [d-Ala] was also the only peptidoglycan precursor detected in C. difficile grown in the presence of vancomycin, corroborating the lack of vancomycin resistance. Peptidoglycan structures of a vanG-like mutant strain and of a strain lacking the vanG-like cluster did not differ from the C. difficile 630 strain, indicating that the vanG-like cluster also has no impact on cell-wall composition.

Cluster ions and van der Waals molecules

CERN Document Server

Smirnov, Boris M

1992-01-01

This review discusses current ideas in the physics and chemistry of cluster ions and Van der Waals molecules as well as presenting numerical data on their parameters and the processes involving them. It is also a detailed reference on basic data relating to many species.

A notable difference between ideal gas and infinite molar volume limit of van der Waals gas

International Nuclear Information System (INIS)

Liu, Q H; Shen, Y; Bai, R L; Wang, X

2010-01-01

The van der Waals equation of state does not sufficiently represent a gas unless a thermodynamic potential with two proper and independent variables is simultaneously determined. The limiting procedures under which the behaviour of the van der Waals gas approaches that of an ideal gas are letting two van der Waals coefficients be zero rather than letting the molar volume become infinitely large; otherwise, the partial derivative of internal energy with respect to pressure at a fixed temperature does not vanish.

A notable difference between ideal gas and infinite molar volume limit of van der Waals gas

Science.gov (United States)

Liu, Q. H.; Shen, Y.; Bai, R. L.; Wang, X.

2010-05-01

The van der Waals equation of state does not sufficiently represent a gas unless a thermodynamic potential with two proper and independent variables is simultaneously determined. The limiting procedures under which the behaviour of the van der Waals gas approaches that of an ideal gas are letting two van der Waals coefficients be zero rather than letting the molar volume become infinitely large; otherwise, the partial derivative of internal energy with respect to pressure at a fixed temperature does not vanish.

Collisions of halogen (2P) and rare gas (1S) atoms

International Nuclear Information System (INIS)

Becker, C.H.

1978-12-01

Differential cross sections I (THETA) at several collision energies measured in crossed molecular beam experiments are reported for several combinations of halogen atoms ( 2 P) scattered off rare gas-rare gas atoms ( 1 S 0 ), namely, F + Ne, F + Ar, F + Kr, F + Xe, C1 + Xe. The scattering is described by an elastic model appropriate to Hund's case c coupling. With the use of this model, the X 1/2, I 3/2, and II 1/2 interaction potential energy curves are derived by fitting calculated differential cross sections, based on analytic representations of the potentials, to the data. The F - Xe X 1/2 potential shows a significant bonding qualitatively different than for the other F-rare gases. The I 3/2 and II 1/2 potentials closely resemble the van der Waals interactions of the one electron richer ground state rare gas-rare gas systems. Coupled-channel scattering calculations are carried out for F + Ar, F + Xe, and C1 + Xe using the realistic potential curves derived earlier. The results justify the use of the elastic model, and give additional information on intramultiplet and intermultiplet transitions. The transitions are found to be governed by the crossing of the two Ω = 1/2 potentials in the complex plane. The measured I (theta) and I (THETA) derived from the coupled-channel computations show small oscillations or perturbations (Stueckelberg oscillations) though quantitative agreement is not obtained.The nature of the anomalous F - Xe X 1/2 potential is discussed as is the approximation of a constant spin orbit coupling over the experimentally accessible range of internuclear distances for these open shell molecules. 55 references

Refined potentials for rare gas atom adsorption on rare gas and alkali-halide surfaces

Science.gov (United States)

Wilson, J. W.; Heinbockel, J. H.; Outlaw, R. A.

1985-01-01

The utilization of models of interatomic potential for physical interaction to estimate the long range attractive potential for rare gases and ions is discussed. The long range attractive force is calculated in terms of the atomic dispersion properties. A data base of atomic dispersion parameters for rare gas atoms, alkali ion, and halogen ions is applied to the study of the repulsive core; the procedure for evaluating the repulsive core of ion interactions is described. The interaction of rare gas atoms on ideal rare gas solid and alkali-halide surfaces is analyzed; zero coverage absorption potentials are derived.

Green Gas. An overview od innovative techniques and suppliers; Groen Gas. Een overzicht van innovatieve technieken en leveranciers

Energy Technology Data Exchange (ETDEWEB)

Van Dorp, R.

2013-04-15

An overview is given of all (innovative) techniques in the whole biogas chain, from biomass to the use of biogas or green gas. Each technique is supplemented with a list of suppliers and links to websites [Dutch] Een overzicht wordt gegeven van alle (innovatieve) technieken over de gehele biogasketen, van biomassa tot toepassing van biogas of groen gas. Elke techniek is aangevuld met een lijst van leveranciers en links naar websites.

Van der Waals coefficients for alkali metal clusters and their size

Indian Academy of Sciences (India)

In this paper we employ the hydrodynamic formulation of time-dependent density functional theory to obtain the van der Waals coefficients 6 and 8 of alkali metal clusters of various sizes including very large clusters. Such calculations become computationally very demanding in the orbital-based Kohn-Sham formalism, ...

Comparative study of energy of particles ejected from coulomb explosion of rare gas and metallic clusters irradiated by intense femtosecond laser field

Science.gov (United States)

Boucerredj, N.; Beggas, K.

2016-10-01

We present our study of high intensity femtosecond laser field interaction with large cluster of Kr and Na (contained 2.103 to 2.107 atoms). When laser intensity is above a critical value, it blows off all of electrons from the cluster and forms a non neutral ion cloud. The irradiation of these clusters by the intense laser field leads to highly excitation energy which can be the source of energetic electrons, electronic emission, highly charge, energetic ions and fragmentation process. During the Coulomb explosion of the resulting highly ionized, high temperature nanoplasma, ions acquire again their energy. It is shown that ultra fast ions are produced. The goal of our study is to investigate in detail a comparative study of the expansion and explosion then the ion energy of metallic and rare gas clusters irradiated by an intense femtosecond laser field. We have found that ions have a kinetic energy up to 105 eV and the Coulomb pressure is little than the hydrodynamic pressure. The Coulomb explosion of a cluster may provide a new high energy ion source.

Energy transfer rates in inhomogeneous van der Waals clusters

International Nuclear Information System (INIS)

Desfrancois, C.; Schermann, J.P.

1991-01-01

The internal energy exchange inside an inhomogeneous van der Waals cluster are investigated by means of molecular dynamic calculations. The very long time scales for relaxation of the high frequency degrees of freedom are examined within the framework of Nekhoroshev's theorem. (orig.)

Influence of reactive gas admixture on transition metal cluster nucleation in a gas aggregation cluster source

Science.gov (United States)

Peter, Tilo; Polonskyi, Oleksandr; Gojdka, Björn; Mohammad Ahadi, Amir; Strunskus, Thomas; Zaporojtchenko, Vladimir; Biederman, Hynek; Faupel, Franz

2012-12-01

We quantitatively assessed the influence of reactive gases on the formation processes of transition metal clusters in a gas aggregation cluster source. A cluster source based on a 2 in. magnetron is used to study the production rate of titanium and cobalt clusters. Argon served as working gas for the DC magnetron discharge, and a small amount of reactive gas (oxygen and nitrogen) is added to promote reactive cluster formation. We found that the cluster production rate depends strongly on the reactive gas concentration for very small amounts of reactive gas (less than 0.1% of total working gas), and no cluster formation takes place in the absence of reactive species. The influence of discharge power, reactive gas concentration, and working gas pressure are investigated using a quartz micro balance in a time resolved manner. The strong influence of reactive gas is explained by a more efficient formation of nucleation seeds for metal-oxide or nitride than for pure metal.

Multiplicity dependence of matrix-induced frequency shifts for atomic transitions of the group 12 metals in rare gas solids

International Nuclear Information System (INIS)

Laursen, S.L.; Cartland, H.E.

1991-01-01

Atomic resonances of the group 12 metal atoms, Hg, Cd, and Zn, undergo frequency shifts from the gas phase atomic line when trapped in rare gas matrices of Ar, Kr, and Xe at 12 K. As expected, the shifts are approximately linear in polarizability of the rare gas, but the slope of this line depends on whether the transition in question is 1 P 1 left-arrow 1 S 0 or 3 P 1 left-arrow 1 S 0 . Thus the matrix-induced frequency shift is dependent on the singlet or triplet nature of the excited state as well as on the matrix material. This dependence on multiplicity is discussed in terms of interactions between the excited-state atomic orbitals and the matrix. The results are compared to matrix studies of other metals and to related gas-phase work on diatomic van der Waals complexes of group 12 metals with rare gases

Episodic cluster headache from a textbook of 1745: van Swieten's classic description.

Science.gov (United States)

Isler, H

1993-06-01

The first description of cluster headache is usually attributed to authors who published between 1867 and 1939, but lately several researchers have found accounts dating back to the 18th or even the 17th century which are incomplete or do not account for cluster headache in the strict sense. However, Gerhard van Swieten gave a full description of a case of episodic cluster headache meeting the IHS criteria in 1745, in his textbook of clinical medicine, the mainstream textbook of Continental medicine in those years, since van Swieten was the founder of the then leading medical centre, the Vienna School. That the case was found again only in 1992 is due to the circumstance that it was published in Latin. It is presented here in an English translation facing the original Latin text.

Molecule Matters van der Waals Molecules

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 12. Molecule Matters van der Waals Molecules - Noble Gas Clusters are London Molecules! E Arunan. Feature Article Volume 14 Issue 12 December 2009 pp 1210-1222 ...

The detection of clusters in rare diseases

Energy Technology Data Exchange (ETDEWEB)

Besag, J. (Washington Univ., Seattle, WA (USA) Newcastle upon Tyne Univ. (UK)); Newell, J. (Newcastle upon Tyne Univ. (UK))

1991-01-01

Tests for clustering of rare diseases investigate whether an observed pattern of cases in one or more geographical regions could reasonably have arisen by chance alone, bearing in mind the variation in background population density. In contrast, tests for the detection of clusters are concerned with screening a large region for evidence of individual 'hot spots' of disease but without any preconception about their likely locations; the results of such tests may form the basis for subsequent small area investigations, statistical or non-statistical, but will rarely be an end in themselves. The main intention of the paper is to describe and illustrate a new technique for the identification of small clusters of disease. A secondary purpose is to discuss some common pitfalls in the application of tests of clustering to epidemiological data. (author).

Van Vleck temperature independent susceptibilities in the rare earth double nitrates

International Nuclear Information System (INIS)

Commander, R.J.; Finn, C.B.P.

1978-01-01

Measurements of the magnetic susceptibilities between 4.2 and 1.1 K of the rare earth zinc nitrates are reported. It is shown that the results for the Van Vleck temperature independent susceptibilities for cerium magnesium nitrate and cerium zinc nitrate are consistent with the published low lying level schemes for these two salts. (author)

Risico's 'groen' gas voor CO2 - dosering ingeschat : Interview met Tom Dueck en Chris van Dijk

NARCIS (Netherlands)

Visser, Peter; Dueck, T.A.; Dijk, van C.J.

2009-01-01

De overheid wil gebruik van duurzaam 'groen gas' ofwel 'biogas' stimuleren. De vraag is of dit gas een verhoogd risico oplevert bij het gebruik van rookgassen voor CO2-dosering in de tuinbouw. Biogas kan mee helpen aan het gebruik van duurzamer energie in de glastuinbouw

Mechanism of electron attachment to van der Waals clusters: Application to carbon dioxide clusters

International Nuclear Information System (INIS)

Tsukada, M.; Shima, N.; Tsuneyuki, S.; Kageshima, H.; Kondow, T.

1987-01-01

A theory on the attachment of very slow electrons to van der Waals clusters was developed on the basis of the electronic structure theory, and was applied to clarify the mechanism of the collisional electron transfer from a high-Rydberg atom to a CO 2 cluster. The strong coupled electron--phonon model is found to afford a reasonable mechanism of the attachment. The equilibrium geometry of (CO 2 )/sub N/ (2≤N≤13) clusters are determined and their vertical affinity levels are obtained by the DV-X α-transition state method. Using this information, as well as some plausible assumptions on the values of the coupling constants, the attachment cross section σ is evaluated as a function of the energy of the incident electron. The theory predicts the existence of the threshold cluster size for the attachment and a sharp decrease of σ with the energy, which are consistent with the experimental results

The first high resolution image of coronal gas in a starbursting cool core cluster

Science.gov (United States)

Johnson, Sean

2017-08-01

Galaxy clusters represent a unique laboratory for directly observing gas cooling and feedback due to their high masses and correspondingly high gas densities and temperatures. Cooling of X-ray gas observed in 1/3 of clusters, known as cool-core clusters, should fuel star formation at prodigious rates, but such high levels of star formation are rarely observed. Feedback from active galactic nuclei (AGN) is a leading explanation for the lack of star formation in most cool clusters, and AGN power is sufficient to offset gas cooling on average. Nevertheless, some cool core clusters exhibit massive starbursts indicating that our understanding of cooling and feedback is incomplete. Observations of 10^5 K coronal gas in cool core clusters through OVI emission offers a sensitive means of testing our understanding of cooling and feedback because OVI emission is a dominant coolant and sensitive tracer of shocked gas. Recently, Hayes et al. 2016 demonstrated that synthetic narrow-band imaging of OVI emission is possible through subtraction of long-pass filters with the ACS+SBC for targets at z=0.23-0.29. Here, we propose to use this exciting new technique to directly image coronal OVI emitting gas at high resolution in Abell 1835, a prototypical starbursting cool-core cluster at z=0.252. Abell 1835 hosts a strong cooling core, massive starburst, radio AGN, and at z=0.252, it offers a unique opportunity to directly image OVI at hi-res in the UV with ACS+SBC. With just 15 orbits of ACS+SBC imaging, the proposed observations will complete the existing rich multi-wavelength dataset available for Abell 1835 to provide new insights into cooling and feedback in clusters.

Secondary ions produced from condensed rare gas targets under highly charged MeV/amu heavy ion bombardment

International Nuclear Information System (INIS)

Tawara, H.; Tonuma, T.; Kumagai, H.; Matsuo, T.

1994-01-01

Secondary ions produced from condensed rare gas targets are observed under MeV/amu, highly charged, heavy ion impact. The intensities of the observed cluster ions decrease smoothly as the cluster sizes become large but show some discontinuities at particular sizes of cluster ions. This seems to be closely related to the stabilities of cluster ion structures. It is also noted that very few doubly charged or practically no triply/higher charged ions have been observed, in sharp contrast to that of some condensed molecular targets. (orig.)

Development of a picture of the van der Waals interaction energy between clusters of nanometer-range particles

International Nuclear Information System (INIS)

Arunachalam, V.; Marlow, W.H.; Lu, J.X.

1998-01-01

The importance of the long-range Lifshitz-van der Waals interaction energy between condensed bodies is well known. However, its implementation for interacting bodies that are highly irregular and separated by distances varying from contact to micrometers has received little attention. As part of a study of collisions of irregular aerosol particles, an approach based on the Lifshitz theory of van der Waals interaction has been developed to compute the interaction energy between a sphere and an aggregate of spheres at all separations. In the first part of this study, the iterated sum-over-dipole interactions between pairs of approximately spherical molecular clusters are compared with the Lifshitz and Lifshitz-Hamaker interaction energies for continuum spheres of radii equal to those of the clusters' circumscribed spheres and of the same masses as the clusters. The Lifshitz energy is shown to converge to the iterated dipolar energy for quasispherical molecular clusters for sufficiently large separations, while the energy calculated by using the Lifshitz-Hamaker approach does not. Next, the interaction energies between a contacting pair of these molecular clusters and a third cluster in different relative positions are calculated first by coupling all molecules in the three-cluster system and second by ignoring the interactions between the molecules of the adhering clusters. The error calculated by this omission is shown to be very small, and is an indication of the error in computing the long-range interaction energy between a pair of interacting spheres and a third sphere as a simple sum over the Lifshitz energies between individual, condensed-matter spheres. This Lifshitz energy calculation is then combined with the short-separation, nonsingular van der Waals energy calculation of Lu, Marlow, and Arunachalam, to provide an integrated picture of the van der Waals energy from large separations to contact. copyright 1998 The American Physical Society

Many-body study of van der Waals interaction involving lithium and rare-gas atoms and its contribution to hyperfine shifts

International Nuclear Information System (INIS)

Rao, B.K.; Das, T.P.

1982-01-01

Using linked cluster many-body perturbation theory, the frequency-dependent dipole polarizabilities a(ω) has been calculated for the lithium atom. The value of a(ω) at the static limit (169.04 a 0 3 ) matches well with other available theoretical values and experimental results. These values have been used to calculate the van der Waals constants for interactions of lithium, helium and neon atoms. The values of the van der Waals constants for dipole-dipole interaction in atomic units are -22.9, -44.8, -1465.8, 184950.0, 2011.8, 3896.5, 30.3, 59.0 and 115.1 for Li-He, Li-Ne, Li-Li, Li-Li-Li, Li-Li-He, Li-Li-Ne, Li-He-He, Li-He-Ne and Li-Ne-Ne interactions respectively. Obtaining the suitable response functions for lithium and helium atoms, the long range contribution to Δa(r)/a 0 in the study of fractional frequency shift in hyperfine pressure and temperature shift measurements is obtained as -541 atomic units. (author)

Gas-fuelled driving and sailing. Cost and environmental effects of natural gas and green gas in transport; Rijden en varen op gas. Kosten en milieueffecten van aardgas en groen gas in transport

Energy Technology Data Exchange (ETDEWEB)

Kampman, B.E.; Croezen, H.J.; Verbraak, G.M.; Brouwer, F.P.E.

2010-06-15

A number of new gaseous fuels for cars and ships is becoming more popular: compressed natural gas (CNG), liquid natural gas (LNG) and biogas. This report presents the results of a study of the costs and environmental effects of these gas applications and compares them to diesel and petrol and the 'common' biofuels biodiesel and bio-ethanol. The green gas applications emit much less CO2 than biodiesel and bio-ethanol from wheat. The air-polluting emissions are much lower in all cases. The basic cost of driving or sailing on these gaseous fuels (excl. levies and taxes) are significantly higher than in case of diesel, but in some cases van be comparable or even lower than in case of liquid biofuels. [Dutch] Een aantal nieuwe gasvormige brandstoffen voor auto's en schepen is in opkomst: aardgas onder druk (CNG), vloeibaar aardgas (LNG) en biogassen. In dit rapport worden de resultaten van een onderzoek naar de kosten en de milieueffecten van deze gastoepassingen gepresenteerd en vergeleken met diesel en benzine en de 'gewone' biobrandstoffen bio-diesel en bio-ethanol. De groen gas-toepassingen stoten aanzienlijk minder CO2 uit dan biodiesel en bio-ethanol uit tarwe. De luchtvervuilende emissies zijn in alle gevallen een stuk lager. De kale kosten van rijden en varen op deze gasvormige brandstoffen (excl. heffingen en belastingen) zijn wel aanzienlijk hoger dan bij diesel, maar kunnen in sommige toepassingen vergelijkbaar of lager uitkomen dan van de vloeibare biobrandstoffen.

Strong increase of profits from oil and natural gas exploitation; Sterke stijging van opbrengsten uit olie- en gaswinning

Energy Technology Data Exchange (ETDEWEB)

Graveland, C.; Veldhuizen, E.; Schenau, S.; Van den Bergen, D. [Centraal Breau voor de Statistiek, Voorburg/Heerlen (Netherlands)

2008-08-15

The amount of oil and natural gas reserves in the Netherlands decreases, although the value of the reserves has increased considerably. The profits are used by the Dutch government in the form of so-called natural gas benefits. [Dutch] De omvang van de Nederlandse olie- en gasreserves daalt gestaag. Desondanks is de waarde van de resterende aardolie- en aardgasreserves flink toegenomen. Dit wordt grotendeels verklaard doordat de winning van olie en gas steeds meer opbrengt. De hogere opbrengsten komen vooral ten goede aan de overheid in de vorm van aardgasbaten, maar ook de winningsbedrijven profiteren er van.

Gas expulsion in highly substructured embedded star clusters

Science.gov (United States)

Farias, J. P.; Fellhauer, M.; Smith, R.; Domínguez, R.; Dabringhausen, J.

2018-06-01

We investigate the response of initially substructured, young, embedded star clusters to instantaneous gas expulsion of their natal gas. We introduce primordial substructure to the stars and the gas by simplistically modelling the star formation process so as to obtain a variety of substructure distributed within our modelled star-forming regions. We show that, by measuring the virial ratio of the stars alone (disregarding the gas completely), we can estimate how much mass a star cluster will retain after gas expulsion to within 10 per cent accuracy, no matter how complex the background structure of the gas is, and we present a simple analytical recipe describing this behaviour. We show that the evolution of the star cluster while still embedded in the natal gas, and the behaviour of the gas before being expelled, is crucial process that affect the time-scale on which the cluster can evolve into a virialized spherical system. Embedded star clusters that have high levels of substructure are subvirial for longer times, enabling them to survive gas expulsion better than a virialized and spherical system. By using a more realistic treatment for the background gas than our previous studies, we find it very difficult to destroy the young clusters with instantaneous gas expulsion. We conclude that gas removal may not be the main culprit for the dissolution of young star clusters.

Method of storing radioactive rare gas. [gas occupies spaces in the zeolite crystal lattice

Energy Technology Data Exchange (ETDEWEB)

Nagao, H; Miharada, H; Takiguchi, Y; Kanazawa, T; Soya, M

1975-05-15

A method is provided to prevent dispersion of radioactive rare gas atoms by sealing them in a pressurised state within zeolite and thereby confining them in position within the zeolite crystal lattice. Radioactive rare gas is separated from exhaust gas and concentrated by using a low temperature adsorption means or liquefaction distillation means and necessary accessory means, and then it is temporarily stored in a gas holder. When a predetermined quantity of storage is reached, the gas is led to a sealing tank containing zeolite heated to 300 to 400/sup 0/C and held at 3,000 to 4,000 atmospheres, and under this condition radioactive rare gas is brought to occupy the spaces in the zeolite crystal lattice. After equilibrium pressure is reached by the pressure in the tank at that temperature, the gas is cooled in the pressurised state down to room temperature. Subsequently, the rare gas remaining in the tank and duct is recovered by a withdrawal pump into the gas holder. Thereafter, the zeolite with radioactive rare gas sealed in it is taken out from the tank and sealed within a long period storage container, which is then housed in a predetermined place for storage.

Fragmentation of neutral van der Waals clusters with visible laser light: A new variant of the Raman effect?

International Nuclear Information System (INIS)

Stamatovic, A.; Howorka, F.; Scheier, P.; Maerk, T.D.

1989-01-01

We have observed strong photodissociation (using visible laser light) of neutral van der Waals clusters (Ar, N 2 , O 2 , CO 2 , SO 2 , NH 3 ) produced by supersonic expansion and detected by electron ionization/mass spectrometer. Several tests were performed, all of them supporting this surprising discovery. We suggest that Raman induced photodissociation (RIP) is responsible for this phenomenon. This first observation of Raman induced photodissociation provides a new technique for the study of neutral van der Waals clusters. (orig.)

BRIGHTEST CLUSTER GALAXIES AND CORE GAS DENSITY IN REXCESS CLUSTERS

International Nuclear Information System (INIS)

Haarsma, Deborah B.; Leisman, Luke; Donahue, Megan; Bruch, Seth; Voit, G. Mark; Boehringer, Hans; Pratt, Gabriel W.; Pierini, Daniele; Croston, Judith H.; Arnaud, Monique

2010-01-01

We investigate the relationship between brightest cluster galaxies (BCGs) and their host clusters using a sample of nearby galaxy clusters from the Representative XMM-Newton Cluster Structure Survey. The sample was imaged with the Southern Observatory for Astrophysical Research in R band to investigate the mass of the old stellar population. Using a metric radius of 12 h -1 kpc, we found that the BCG luminosity depends weakly on overall cluster mass as L BCG ∝ M 0.18±0.07 cl , consistent with previous work. We found that 90% of the BCGs are located within 0.035 r 500 of the peak of the X-ray emission, including all of the cool core (CC) clusters. We also found an unexpected correlation between the BCG metric luminosity and the core gas density for non-cool-core (non-CC) clusters, following a power law of n e ∝ L 2.7±0.4 BCG (where n e is measured at 0.008 r 500 ). The correlation is not easily explained by star formation (which is weak in non-CC clusters) or overall cluster mass (which is not correlated with core gas density). The trend persists even when the BCG is not located near the peak of the X-ray emission, so proximity is not necessary. We suggest that, for non-CC clusters, this correlation implies that the same process that sets the central entropy of the cluster gas also determines the central stellar density of the BCG, and that this underlying physical process is likely to be mergers.

Energy from fermentation gas. Testing of basic design; Energie uit gistingsgas. Toetsing van ontwerpgrondslagen

Energy Technology Data Exchange (ETDEWEB)

NONE

1983-07-01

When stabilizing sewage sludge by means of fermentation, fermentation gas is released, consisting for 67% of methane. This gas is an important energy source for waste water treatment plants (wwtp). A previous STORA study (Fermentation gas as a source of energy in waste water treatment plants; 1981) has shown that the most significant energy saving in wwtps using sludge fermentation can be realized through energy generation. The aim of this study is to assess the current practical situation of wwtps that are in operation and generate their own energy. The main parameters in determining the appeal of own energy generation have been examined for these wwtps and compared to the technological and economic starting points of the study from 1981. The results indicate whether and which optimizations are possible for existing and new own systems for generating energy and which parameters from the previous STORA study need to be revised [Dutch] Bij stabilisatie van zuiveringsslib door middel van gisting komt gistingsgas vrij, dat voor circa 67% uit methaan bestaat. Dit gas vormt een belangrijke energiebron voor rioolwaterzuiveringsinrichtingen (rwzi). In een eerder STORA-onderzoek (Gistingsgas als energiebron op rioolwaterzuiveringsinrichtingen; 1981) is gebleken, dat de belangrijkste energiebesparing op rwzi's met slibgisting kan worden verkregen door toepassing van eigen energieopwekking. Doelstelling van deze studie is de huidige praktijksituatie op de reeds in bedrijf zijnde rwzi's met eigen energieopwekking na te gaan. De belangrijkste parameters die de aantrekkelijkheid van eigen energieopwekking bepalen, zijn voor deze rwzi's nader onderzocht en vergeleken met de technologische en economische uitgangspunten van het onderzoek uit 1981. De resultaten geven aan of en welke optimalisaties voor bestaande en nieuwe eigen energieopwekkingssystemen mogelijk zijn, en welke parameters in de eerdere STORA-studie opnieuw moeten worden bezien.

Coherent and non coherent atom optics experiment with an ultra-narrow beam of metastable rare gas atoms

International Nuclear Information System (INIS)

Grucker, J.

2007-12-01

In this thesis, we present a new type of atomic source: an ultra-narrow beam of metastable atoms produced by resonant metastability exchange inside a supersonic beam of rare gas atoms. We used the coherence properties of this beam to observe the diffraction of metastable helium, argon and neon atoms by a nano-transmission grating and by micro-reflection-gratings. Then, we evidenced transitions between Zeeman sublevels of neon metastable 3 P 2 state due to the quadrupolar part of Van der Waals potential. After we showed experimental proofs of the observation of this phenomenon, we calculated the transition probabilities in the Landau - Zener model. We discussed the interest of Van der Waals - Zeeman transitions for atom interferometry. Last, we described the Zeeman cooling of the supersonic metastable argon beam ( 3 P 2 ). We have succeeded in slowing down atoms to speeds below 100 m/s. We gave experimental details and showed the first time-of-flight measurements of slowed atoms

Systematic adaptive cluster sampling for the assessment of rare tree species in Nepal

NARCIS (Netherlands)

Acharya, B.; Bhattarai, G.; Gier, de A.; Stein, A.

2000-01-01

Sampling to assess rare tree species poses methodic problems, because they may cluster and many plots with no such trees are to be expected. We used systematic adaptive cluster sampling (SACS) to sample three rare tree species in a forest area of about 40 ha in Nepal. We checked its applicability

Theoretical study of the interaction between intense laser pulses and rare gas clusters; Etude theorique de l'interaction entre une impulsion laser intense et un agregat de gaz rare

Energy Technology Data Exchange (ETDEWEB)

Micheau, S

2007-07-15

The irradiation of nanometer-scale rare gas clusters by a short (a few hundreds of femtosecond) and intense (I > 10{sup 15} W/cm{sup 2}) laser pulse yields multi-keV short X-ray bursts. We employ an hydrodynamic model, the so-called 'nano-plasma model', to understand the mechanisms that tailor the interaction. In this model, the cluster is treated as a dielectric sphere embedded in the quasi-static laser field leading to the formation of a plasma of nano-metric size. We have shown that this model cannot reproduce the experimental results such as the high ionization states and associated X-ray spectra. We have thus included in the model two additional mechanisms that significantly improve the ionization dynamics. First, we have introduced high order ionization processes involving intermediate excited states X{sup q+} + e{sup -} {yields} X{sup q+*} + e{sup -} {yields}... {yields} X{sup q+1+} + 2 e{sup -}. We have used a model potential approach to describe the electronic structure of the cluster's ions (and atoms), and we have computed the total excitation and ionization cross-sections in the distorted-wave Born approximation. Secondly we have studied the influence of screening phenomena induced by the electronic density on the interaction dynamics. By using a sophisticated potential, we have shown that screening effects enhance ionization and lower excitation cross sections with respect to the unscreened data. The improved nano-plasma model allows us to reproduce the populations of highly charged states experimentally observed, and the variation of argon He{sub {alpha}} emission with respect to the various experimental parameters (cluster size, laser pulse duration, intensity and wavelength). We have further computed time- and energy-resolved X-ray spectra which emphasize ultra-short emission duration (less than 100 fs), and therefore indicate that cluster-based X-ray sources are adequate to ultrafast X-ray science applications. (author)

Die konteks vir die keuse van geriefsvoedsel van bepaalde ...

African Journals Online (AJOL)

Seugnet

70. Die konteks vir die keuse van geriefsvoedsel van bepaalde beroepsvroue *. Martha Kok en Priscilla Botha. ABSTRACT. The purpose of this research is to understand and describe the context in which career women choose, purchase and use convenience food (CF). A person is rarely isolated from or unaffected by.

Oligomeric rare-earth metal cluster complexes with endohedral transition metal atoms

Energy Technology Data Exchange (ETDEWEB)

Steinberg, Simon; Zimmermann, Sina; Brühmann, Matthias; Meyer, Eva; Rustige, Christian; Wolberg, Marike; Daub, Kathrin; Bell, Thomas; Meyer, Gerd, E-mail: gerd.meyer@uni-koeln.de

2014-11-15

Comproportionation reactions of rare-earth metal trihalides (RX{sub 3}) with the respective rare-earth metals (R) and transition metals (T) led to the formation of 22 oligomeric R cluster halides encapsulating T, in 19 cases for the first time. The structures of these compounds were determined by single-crystal X-ray diffraction and are composed of trimers ((T{sub 3}R{sub 11})X{sub 15}-type, P6{sub 3}/m), tetramers ((T{sub 4}R{sub 16})X{sub 28}(R{sub 4}) (P-43m), (T{sub 4}R{sub 16})X{sub 20} (P4{sub 2}/nnm), (T{sub 4}R{sub 16})X{sub 24}(RX{sub 3}){sub 4} (I4{sub 1}/a) and (T{sub 4}R{sub 16})X{sub 23} (C2/m) types of structure) and pentamers ((Ru{sub 5}La{sub 14}){sub 2}Br{sub 39}, Cc) of (TR{sub r}){sub n} (n=2–5) clusters. These oligomers are further enveloped by inner (X{sup i}) as well as outer (X{sup a}) halido ligands, which possess diverse functionalities and interconnect like oligomers through i–i, i–a and/or a–i bridges. The general features of the crystal structures for these new compounds are discussed and compared to literature entries as well as different structure types with oligomeric T centered R clusters. Dimers and tetramers originating from the aggregation of (TR{sub 6}) octahedra via common edges are more frequent than trimers and pentamers, in which the (TR{sub r}) clusters share common faces. - Graphical abstract: Rare earth-metal cluster complexes with endohedral transition metal atoms (TR{sub 6}) may connect via common edges or faces to form dimers, trimers, tetramers and pentamers of which the tetramers are the most prolific. Packing effects and electron counts play an important role. - Highlights: • Rare-earth metal cluster complexes encapsulate transition metal atoms. • Oligomers are built via connection of octahedral clusters via common edges or faces. • Dimers through pentamers with closed structures are known. • Tetramers including a tetrahedron of endohedral atoms are the most prolific.

EPR investigation of electronic excitations in rare gas solids (Review Article)

Science.gov (United States)

Zhitnikov, R. A.; Dmitriev, Yu. A.

1998-10-01

The methods are described for producing unstable paramagnetic excited states in rare gas cryocrystals Ne, Ar, Kr, and Xe through the trapping, in the cryocrystals growing from the gas phase, the products of the gas discharge taking place in the same or other rare gas. The paper presents a technique and results of an observation and investigation of excited states in rare gas cryocrystals with electron paramagnetic resonance (EPR). The discovered unstable paramagnetic centers are interpreted as being local metastable excited np5(n+1)s atomic-type states in rare gas cryocrystals which are subject to the action of the anisotropic electric field resulted from the crystal surroundings distorted by the center. An account is given of the mechanisms for formation of observed paramagnetic excited states in cryocrystals which arise owing to the excitation energy of the metastable 3P2 atoms of Ne, Ar, Kr, Xe and He 23S1 and 21S0 atoms that form in the discharge in an appropriate gas and trap in the growing cryocrystal.

Comparative investigation of pure and mixed rare gas atoms on coronene molecules.

Science.gov (United States)

Rodríguez-Cantano, Rocío; Bartolomei, Massimiliano; Hernández, Marta I; Campos-Martínez, José; González-Lezana, Tomás; Villarreal, Pablo; Pérez de Tudela, Ricardo; Pirani, Fernando; Hernández-Rojas, Javier; Bretón, José

2017-01-21

Clusters formed by the combination of rare gas (RG) atoms of He, Ne, Ar, and Kr on coronene have been investigated by means of a basin-hopping algorithm and path integral Monte Carlo calculations at T = 2 K. Energies and geometries have been obtained and the role played by the specific RG-RG and RG-coronene interactions on the final results is analysed in detail. Signatures of diffuse behavior of the He atoms on the surface of the coronene are in contrast with the localization of the heavier species, Ar and Kr. The observed coexistence of various geometries for Ne suggests the motion of the RG atoms on the multi-well potential energy surface landscape offered by the coronene. Therefore, the investigation of different clusters enables a comparative analysis of localized versus non-localized features. Mixed Ar-He-coronene clusters have also been considered and the competition of the RG atoms to occupy the docking sites on the molecule is discussed. All the obtained information is crucial to assess the behavior of coronene, a prototypical polycyclic aromatic hydrocarbon clustering with RG atoms at a temperature close to that of interstellar medium, which arises from the critical balance of the interactions involved.

Infrared spectroscopy of gas-phase clusters using a free-electron laser

International Nuclear Information System (INIS)

Heijnsbergen, D. van; Helden, G. von; Meijer, G.

2002-01-01

Most clusters produced in the gas phase, especially those containing metals, remain largely uncharaterized, among these are transition metal - carbide, -oxide and -nitride clusters. A method for recording IR spectra of strongly bound gas-phase clusters is presented. It is based on a free-electron laser called Felix, characterized by wide wavelength tuning range, covering almost the full 'molecular finger print' region, high power and fluence which make it suited to excite gas-phase species i.e. gas -phase clusters. Neutral clusters were generated by laser vaporization technique, ions that were created after the interaction with the free-electron laser were analyzed in a flight mass spectrometer. Experiments were run with titanium carbide clusters and their IR spectra given. It was shown that this method is suited to strongly bound clusters with low ionization energies, a condition met for many pure metal clusters and metal compound clusters. (nevyjel)

Critical radius and critical number of gas atoms for cavities containing a Van der Waals gas

International Nuclear Information System (INIS)

Coghlan, W.A.; Mansur, L.K.

1983-01-01

The effect of gas on void nucleation and growth is particularly important for structural materials in fusion reactors because of the high production of helium by neutron-induced transmutation reactions. Gas reduces the critical radius for bias driven growth and there is a critical number of gas atoms, n/sub g/*, at which the critical radius is reduced essentially to zero. The significance of this is that the time interval to the accumulation of n/sub g/* gas atoms may determine the time to the onset of bias driven swelling where n/sub g/* is large. In previous papers these critical quantities were given for an ideal gas. Recently, we presented the results for a Van der Waals gas. Here the derivation of these relations is presented and further results of calculations are given. At low temperatures (high pressures) the results depart from those of the ideal gas, with the critical number affected more strongly than the critical radius. Comparisons are made with earlier calculations

Spin polarization of a magnetic electron gas induced by a van Vleck ion

International Nuclear Information System (INIS)

Palermo, L.; Silva, X.A. do

1978-11-01

The mutual polarization of a magnetic electron gas and a van Vleck ion, interacting via exchange, are theoretically investigated using the double-time Green function method. A pair of equations describing the dynamics of the electron gas and the ion are conveniently decoupled and an analytic expression for the electron gas polarization, which depends on the square of the exchange parameter, is obtained. Besides a RKKY-like term, a new term associated to the process of formation of the magnetic moment of the ion appears [pt

Versatile Rare Earth Hexanuclear Clusters for the Design and Synthesis of Highly-connected ftw-MOFs

KAUST Repository

Eddaoudi, Mohamed

2015-04-15

A series of highly porous MOFs were deliberately targeted to contain a 12-connected rare earth hexanuclear cluster and quadrangular tetracarboxylate ligands. The resultant MOFs have an underlying topology of ftw, (4, 12)-c ftw-MOFs. This targeted RE ftw-MOF platform offers potential to assess the effect of pore functionality and size, via ligand functionalization and/or expansion, on adsorption properties of relevant gases. Examination of gas adsorption properties of these compounds showed that the ftw-MOF-2 analogues, constructed from rigid ligands having a phenyl, a naphthyl or an anthracene core, exhibited a relatively high degree of porosity. The specific surface areas and pore volumes of these analogs are amongst the highest reported for rare earth based MOFs. Further studies reveal that Y-ftw-MOF-2 shows promising attributes as a storage media for methane (CH4) at high pressures. Furthermore, Y-ftw-MOF-2 shows potential as a separation agent for the selective removal of normal butane (n-C4H10) and propane (C3H8) from natural gas (NG) as well as interesting properties for the selective separation of n-C4H10 from C3H8 or isobutane (iso-C4H10).

Infra-red absorption in rare-gas mixtures

International Nuclear Information System (INIS)

Weiss, S.

1980-01-01

Infrared absorption in rare-gas mixtures has been studied extensively, so that by now the spectra at room temperature of almost all pairs are available. Turning attention first to the gas phase, it is shown that the considerable mass of experimental results can be reduced to yield a relatively simple picture. Having reviewed the experimental facts, the interpretation and extraction of information is discussed. (KBE)

Quest for Highly-connected MOF Platforms: Rare-Earth Polynuclear Clusters Versatility Meets Net Topology Needs.

KAUST Repository

Alezi, Dalal

2015-04-07

Gaining control over the assembly of highly porous rare-earth (RE) based metal-organic frameworks (MOFs) remains challenging. Here we report the latest discoveries on our continuous quest for highly-connected nets. The topological exploration based on the non-compatibility of 12-connected RE polynuclear carboxylate-based cluster, points of extension matching the 12 vertices of the cuboctahedron (cuo), with 3-connected organic ligands led to the discovery of two fascinating and highly-connected minimal edge-transitive nets, pek and aea. The reduced symmetry of the employed triangular tricarboxylate ligand, as compared to the prototype highly symmetrical 1,3,5-benzene(tris)benzoic acid guided the concurrent occurrence of nonanuclear [RE9(μ3-OH)12(μ3-O)2(O2C–)12] and hexanuclear [RE6(OH)8(O2C–)8] carboxylate-based clusters as 12-connected and 8-connected molecular building blocks in the structure of a 3-periodic pek-MOF based on a novel (3,8,12)-c trinodal net. The use of a tricarboxylate ligand with modified angles between carboxylate moieties led to the formation of a second MOF containing solely nonanuclear clusters and exhibiting once more a novel and a highly-connected (3,12,12)-c trinodal net with aea topology. Notably, it is the first time that RE-MOFs with double six-membered ring (d6R) secondary building units are isolated, representing therefore a critical step forward toward the design of novel and highly coordinated materials using the supermolecular building layer approach while considering the d6Rs as building pillars. Lastly, the potential of these new MOFs for gas separation/storage was investigated by performing gas adsorption studies of various probe gas molecules over a wide range of pressures. Noticeably, pek-MOF-1 showed excellent volumetric CO2 and CH4 uptakes at high pressures.

Clustering impact regime with shocks in freely evolving granular gas

Science.gov (United States)

Isobe, Masaharu

2017-06-01

A freely cooling granular gas without any external force evolves from the initial homogeneous state to the inhomogeneous clustering state, at which the energy decay deviates from the Haff's law. The asymptotic behavior of energy in the inelastic hard sphere model have been predicted by several theories, which are based on the mode coupling theory or extension of inelastic hard rods gas. In this study, we revisited the clustering regime of freely evolving granular gas via large-scale molecular dynamics simulation with up to 16.7 million inelastic hard disks. We found novel regime regarding on collisions between "clusters" spontaneously appearing after clustering regime, which can only be identified more than a few million particles system. The volumetric dilatation pattern of semicircular shape originated from density shock propagation are well characterized on the appearing of "cluster impact" during the aggregation process of clusters.

Noncovalent Halogen Bonding as a Mechanism for Gas-Phase Clustering

DEFF Research Database (Denmark)

Wegeberg, Christina; Donald, William A.; McKenzie, Christine

2017-01-01

in the crystalline phases of PhIO2 and its derivatives serve as models for the structures of larger gas-phase clusters, and calculations on simple model gas-phase dimer and trimer clusters result in similar motifs. This is the first account of halogen bonding playing an extensive role in gas-phase associations....

Weighing galaxy clusters with gas. II. On the origin of hydrostatic mass bias in ΛCDM galaxy clusters

International Nuclear Information System (INIS)

Nelson, Kaylea; Nagai, Daisuke; Yu, Liang; Lau, Erwin T.; Rudd, Douglas H.

2014-01-01

The use of galaxy clusters as cosmological probes hinges on our ability to measure their masses accurately and with high precision. Hydrostatic mass is one of the most common methods for estimating the masses of individual galaxy clusters, which suffer from biases due to departures from hydrostatic equilibrium. Using a large, mass-limited sample of massive galaxy clusters from a high-resolution hydrodynamical cosmological simulation, in this work we show that in addition to turbulent and bulk gas velocities, acceleration of gas introduces biases in the hydrostatic mass estimate of galaxy clusters. In unrelaxed clusters, the acceleration bias is comparable to the bias due to non-thermal pressure associated with merger-induced turbulent and bulk gas motions. In relaxed clusters, the mean mass bias due to acceleration is small (≲ 3%), but the scatter in the mass bias can be reduced by accounting for gas acceleration. Additionally, this acceleration bias is greater in the outskirts of higher redshift clusters where mergers are more frequent and clusters are accreting more rapidly. Since gas acceleration cannot be observed directly, it introduces an irreducible bias for hydrostatic mass estimates. This acceleration bias places limits on how well we can recover cluster masses from future X-ray and microwave observations. We discuss implications for cluster mass estimates based on X-ray, Sunyaev-Zel'dovich effect, and gravitational lensing observations and their impact on cluster cosmology.

Origin of planetary primordial rare gas - The possible role of adsorption.

Science.gov (United States)

Fanale, F. P.; Cannon, W. A.

1972-01-01

The degree of physical adsorption of Ne, Ar, Kr, and Xe on pulverized samples of the Allende meteorite at 113 K has been measured. The observed pattern of equilibrium enrichment of heavy rare gases over light on the pulverized meteorite surfaces relative to the gas phase is similar to the enrichment pattern exhibited by planetary primordial rare gas when compared with the composition of solar rare gas. Results indicate that, at 113 K, a total nebular pressure of from .01 to .001 atm would be required to explain the Ar, Kr, and Xe abundances in carbonaceous chondrites with an adsorption mechanism. This pressure estimate is compatible with the range of possible nebular pressures suggested by astrophysical arguments. However, the subsequent mechanism by which initially adsorbed gas might have been transferred into the interiors of grains cannot be identified at present.

Closed-cage tungsten oxide clusters in the gas phase.

Science.gov (United States)

Singh, D M David Jeba; Pradeep, T; Thirumoorthy, Krishnan; Balasubramanian, Krishnan

2010-05-06

During the course of a study on the clustering of W-Se and W-S mixtures in the gas phase using laser desorption ionization (LDI) mass spectrometry, we observed several anionic W-O clusters. Three distinct species, W(6)O(19)(-), W(13)O(29)(-), and W(14)O(32)(-), stand out as intense peaks in the regular mass spectral pattern of tungsten oxide clusters suggesting unusual stabilities for them. Moreover, these clusters do not fragment in the postsource decay analysis. While trying to understand the precursor material, which produced these clusters, we found the presence of nanoscale forms of tungsten oxide. The structure and thermodynamic parameters of tungsten clusters have been explored using relativistic quantum chemical methods. Our computed results of atomization energy are consistent with the observed LDI mass spectra. The computational results suggest that the clusters observed have closed-cage structure. These distinct W(13) and W(14) clusters were observed for the first time in the gas phase.

Gas expulsion vs gas retention in young stellar clusters II: effects of cooling and mass segregation

Science.gov (United States)

Silich, Sergiy; Tenorio-Tagle, Guillermo

2018-05-01

Gas expulsion or gas retention is a central issue in most of the models for multiple stellar populations and light element anti-correlations in globular clusters. The success of the residual matter expulsion or its retention within young stellar clusters has also a fundamental importance in order to understand how star formation proceeds in present-day and ancient star-forming galaxies and if proto-globular clusters with multiple stellar populations are formed in the present epoch. It is usually suggested that either the residual gas is rapidly ejected from star-forming clouds by stellar winds and supernova explosions, or that the enrichment of the residual gas and the formation of the second stellar generation occur so rapidly, that the negative stellar feedback is not significant. Here we continue our study of the early development of star clusters in the extreme environments and discuss the restrictions that strong radiative cooling and stellar mass segregation provide on the gas expulsion from dense star-forming clouds. A large range of physical initial conditions in star-forming clouds which include the star-forming cloud mass, compactness, gas metallicity, star formation efficiency and effects of massive stars segregation are discussed. It is shown that in sufficiently massive and compact clusters hot shocked winds around individual massive stars may cool before merging with their neighbors. This dramatically reduces the negative stellar feedback, prevents the development of the global star cluster wind and expulsion of the residual and the processed matter into the ambient interstellar medium. The critical lines which separate the gas expulsion and the gas retention regimes are obtained.

WARM GAS IN THE VIRGO CLUSTER. I. DISTRIBUTION OF Lyα ABSORBERS

International Nuclear Information System (INIS)

Yoon, Joo Heon; Putman, Mary E.; Bryan, Greg L.; Thom, Christopher; Chen, Hsiao-Wen

2012-01-01

The first systematic study of the warm gas (T = 10 4–5 K) distribution across a galaxy cluster is presented using multiple background QSOs in and around the Virgo Cluster. We detect 25 Lyα absorbers (N HI = 10 13.1–15.4 cm –2 ) in the Virgo velocity range toward 9 of 12 QSO sightlines observed with the Cosmic Origin Spectrograph, with a cluster impact parameter range of 0.36-1.65 Mpc (0.23-1.05 R vir ). Including 18 Lyα absorbers previously detected by STIS or GHRS toward 7 of 11 background QSOs in and around the Virgo Cluster, we establish a sample of 43 absorbers toward a total of 23 background probes for studying the incidence of Lyα absorbers in and around the Virgo Cluster. With these absorbers, we find (1) warm gas is predominantly in the outskirts of the cluster and avoids the X-ray-detected hot intracluster medium (ICM). Also, Lyα absorption strength increases with cluster impact parameter. (2) Lyα-absorbing warm gas traces cold H I-emitting gas in the substructures of the Virgo Cluster. (3) Including the absorbers associated with the surrounding substructures, the warm gas covering fraction (100% for N HI > 10 13.1 cm –2 ) is in agreement with cosmological simulations. We speculate that the observed warm gas is part of large-scale gas flows feeding the cluster both in the ICM and galaxies.

Gas cluster ion beam equipments for industrial applications

International Nuclear Information System (INIS)

Matsuo, J.; Takaoka, G.H.; Yamada, I.

1995-01-01

30 keV and 200 keV gas cluster ion beam equipments have been developed for industrial applications. A gas cluster source with a non-cooled nozzle was used for both the equipments. Sufficient monomer ion suppression was achieved by using an ExB filter and chromatic lenses mass filter with low extraction voltage. These equipments are suitable to be used for low-damage surface treatment of metals, insulators and semiconductors without heavy metal contamination. (orig.)

MASSIVE CLUSTERS IN THE INNER REGIONS OF NGC 1365: CLUSTER FORMATION AND GAS DYNAMICS IN GALACTIC BARS

International Nuclear Information System (INIS)

Elmegreen, Bruce G.; Galliano, Emmanuel; Alloin, Danielle

2009-01-01

Cluster formation and gas dynamics in the central regions of barred galaxies are not well understood. This paper reviews the environment of three 10 7 M sun clusters near the inner Lindblad resonance (ILR) of the barred spiral NGC 1365. The morphology, mass, and flow of H I and CO gas in the spiral and barred regions are examined for evidence of the location and mechanism of cluster formation. The accretion rate is compared with the star formation rate to infer the lifetime of the starburst. The gas appears to move from inside corotation in the spiral region to looping filaments in the interbar region at a rate of ∼6 M sun yr -1 before impacting the bar dustlane somewhere along its length. The gas in this dustlane moves inward, growing in flux as a result of the accretion to ∼40 M sun yr -1 near the ILR. This inner rate exceeds the current nuclear star formation rate by a factor of 4, suggesting continued buildup of nuclear mass for another ∼0.5 Gyr. The bar may be only 1-2 Gyr old. Extrapolating the bar flow back in time, we infer that the clusters formed in the bar dustlane outside the central dust ring at a position where an interbar filament currently impacts the lane. The ram pressure from this impact is comparable to the pressure in the bar dustlane, and both are comparable to the pressure in the massive clusters. Impact triggering is suggested. The isothermal assumption in numerical simulations seems inappropriate for the rarefaction parts of spiral and bar gas flows. The clusters have enough lower-mass counterparts to suggest they are part of a normal power-law mass distribution. Gas trapping in the most massive clusters could explain their [Ne II] emission, which is not evident from the lower-mass clusters nearby.

Metastable decay and binding energies of van der Waals cluster ions

International Nuclear Information System (INIS)

Ernstberger, B.; Krause, H.; Neusser, H.J.

1991-01-01

In this work the appearance potentials for the metastable decay channel of a series of van der Waals dimer ions are presented. Ionization and metastable dissociation is achieved by resonance-enhanced two-photon absorption in a linear reflectron time-of-flight mass spectrometer. From the appearance potentials the binding energy of the neutral dimers is obtained and from the additionally measured ionization potentials binding energies of the dimer cations are achieved. The contribution of charge transfer resonance interaction to the binding in cluster ions is evaluated by investigation of several homo- and heterodimers of aromatic components and the heterodimer benzene/cyclohexane as an example for a dimer consisting of an aromatic and a nonaromatic component. (orig.)

Coherent and non coherent atom optics experiment with an ultra-narrow beam of metastable rare gas atoms; Experiences d'optique atomique coherente ou non avec un jet superfin d'atomes metastables de gaz rares

Energy Technology Data Exchange (ETDEWEB)

Grucker, J

2007-12-15

In this thesis, we present a new type of atomic source: an ultra-narrow beam of metastable atoms produced by resonant metastability exchange inside a supersonic beam of rare gas atoms. We used the coherence properties of this beam to observe the diffraction of metastable helium, argon and neon atoms by a nano-transmission grating and by micro-reflection-gratings. Then, we evidenced transitions between Zeeman sublevels of neon metastable {sup 3}P{sub 2} state due to the quadrupolar part of Van der Waals potential. After we showed experimental proofs of the observation of this phenomenon, we calculated the transition probabilities in the Landau - Zener model. We discussed the interest of Van der Waals - Zeeman transitions for atom interferometry. Last, we described the Zeeman cooling of the supersonic metastable argon beam ({sup 3}P{sub 2}). We have succeeded in slowing down atoms to speeds below 100 m/s. We gave experimental details and showed the first time-of-flight measurements of slowed atoms.

Calculated apparent yields of rare gas fission products

International Nuclear Information System (INIS)

Delucchi, A.A.

1975-01-01

The apparent fission yield of the rare gas fission products from four mass chains is calculated as a function of separation time for six different fissioning systems. A plot of the calculated fission yield along with a one standard deviation error band is given for each rare gas fission product and for each fissioning system. Those parameters in the calculation that were major contributors to the calculated standard deviation at each separation time were identified and the results presented on a separate plot. To extend the usefulness of these calculations as new and better values for the input parameters become available, a third plot was generated for each system which shows how sensitive the derived fission yield is to a change in any given parameter used in the calculation. (U.S.)

Energy Price Comparisons. Study on the quality of comparison sites for electricity and natural gas on the Internet; Energieprijsvergelijkers. Onderzoek naar de kwaliteit van vergelijkingssites voor elektriciteit en gas op het internet

Energy Technology Data Exchange (ETDEWEB)

Boezaard, P.M.; Van Liere, M.M.; Van Steenpaal, D.F.J.M.

2007-06-15

Internet sites with comparisons of prices for electricity and natural gas appear to be important tools for consumers. On a regular basis the Dutch Office of Energy Regulation (DTe) carries out a study on the quality of such price comparison sites. In this report the results of the June 2007 study are summarized. [Dutch] Voor een goedwerkende markt is een goed geinformeerde consument van belang. Uit de Consumentenmonitor, kwalitatief onderzoek dat de NMa in 2006 heeft laten uitvoeren, is gebleken dat de consument bij een overstap vaak gebruik maakt van prijsvergelijkingssites. Het belang van dergelijke sites neemt alleen maar toe. Door een grotere differentiatie aan producten en meer variatie in prijsstelling wordt een goede vergelijking van energieleveranciers voor de gemiddelde consument steeds lastiger. Ook voor de prijsvergelijkingssites neemt de complexiteit toe. De Directie Toezicht Energie (DTe) van de Nederlandse Mededingingsautoriteit (NMa) onderzoekt sinds 2004 jaarlijks de kwaliteit van (prijs)vergelijkingssites voor elektriciteit en gas. Gezien de groeiende complexiteit van de prijsvergelijkingen is het van belang dat de NMa dit onderzoek ook in 2007 uitvoert. In dit rapport worden de resultaten van dit jaar gepresenteerd. Daarnaast heeft de NMa voor het eerst een handleiding met tips voor de consument als bijlage bij dit rapport opgenomen.

Van Allen Probes, THEMIS, GOES, and Cluster Observations of EMIC Waves, ULF Pulsations, and an Electron Flux Dropout

Science.gov (United States)

Sigsbee, K.; Kletzing, C. A.; Smith, C. W.; Macdowall, R.; Spence, H.; Reeves, G.; Blake, J. B.; Baker, D. N.; Green, J. C.; Singer, H. J.;

Recent development in clusters of rare earths and actinides. Chemistry and materials

Energy Technology Data Exchange (ETDEWEB)

Zheng, Zhiping (ed.) [Arizona Univ., Tucson, AZ (United States). Dept. of Chemistry and Biochemistry

2017-02-01

This book contains the following eight contributions: 1. Lanthanide Hydroxide Cluster Complexes via Ligand-Controlled Hydrolysis of the Lanthanide Ions (Zhonghao Zhang, Yanan Zhang, and Zhiping Zheng); 2. Synthesis and Structures of Lanthanide-Transition Metal Clusters (Xiu-Ying Zheng, Xiang-Jian Kong, and La-Sheng Long); 3. Hydrothermal Synthesis of Lanthanide and Lanthanide-Transition-Metal Cluster Organic Frameworks via Synergistic Coordination Strategy (Jian-Wen Cheng and Guo-Yu Yang); 4. Oxo Clusters of 5f Elements (Sarah Hickam and Peter C.); 5. Construction and Luminescence Properties of 4f and d-4f Clusters with Salen-Type Schiff Base Ligands (Xiaoping Yang, Shiqing Wang, Chengri Wang, Shaoming Huang, and Richard A.); 6. 4f-Clusters for Cryogenic Magnetic Cooling (Yan-Cong Chen, Jun-Liang Liu, and Ming-Liang Tong); 7. Lanthanide Clusters Toward Single-Molecule Magnets (Tian Han, You-Song Ding, and Yan-Zhen Zheng); 8. Molecular Rare Earth Hydride Clusters (Takanori Shima and Zhaomin Hou).

Recent development in clusters of rare earths and actinides. Chemistry and materials

International Nuclear Information System (INIS)

Zheng, Zhiping

2017-01-01

This book contains the following eight contributions: 1. Lanthanide Hydroxide Cluster Complexes via Ligand-Controlled Hydrolysis of the Lanthanide Ions (Zhonghao Zhang, Yanan Zhang, and Zhiping Zheng); 2. Synthesis and Structures of Lanthanide-Transition Metal Clusters (Xiu-Ying Zheng, Xiang-Jian Kong, and La-Sheng Long); 3. Hydrothermal Synthesis of Lanthanide and Lanthanide-Transition-Metal Cluster Organic Frameworks via Synergistic Coordination Strategy (Jian-Wen Cheng and Guo-Yu Yang); 4. Oxo Clusters of 5f Elements (Sarah Hickam and Peter C.); 5. Construction and Luminescence Properties of 4f and d-4f Clusters with Salen-Type Schiff Base Ligands (Xiaoping Yang, Shiqing Wang, Chengri Wang, Shaoming Huang, and Richard A.); 6. 4f-Clusters for Cryogenic Magnetic Cooling (Yan-Cong Chen, Jun-Liang Liu, and Ming-Liang Tong); 7. Lanthanide Clusters Toward Single-Molecule Magnets (Tian Han, You-Song Ding, and Yan-Zhen Zheng); 8. Molecular Rare Earth Hydride Clusters (Takanori Shima and Zhaomin Hou).

ALMA Observations of Gas-rich Galaxies in z ∼ 1.6 Galaxy Clusters: Evidence for Higher Gas Fractions in High-density Environments

Energy Technology Data Exchange (ETDEWEB)

Noble, A. G.; McDonald, M. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Muzzin, A. [Department of Physics and Astronomy, York University, 4700 Keele Street, Toronto, ON MJ3 1P3 (Canada); Nantais, J. [Departamento de Ciencias Físicas, Universidad Andres Bello, Fernandez Concha 700, Las Condes 7591538, Santiago, Región Metropolitana (Chile); Rudnick, G. [The University of Kansas, Department of Physics and Astronomy, 1251 Wescoe Hall Drive, Lawrence, KS 66045 (United States); Van Kampen, E.; Manilla-Robles, A. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München (Germany); Webb, T. M. A.; Delahaye, A. [Department of Physics, McGill University, 3600 rue University, Montréal, QC H3A 2T8 (Canada); Wilson, G.; DeGroot, A.; Foltz, R. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Yee, H. K. C. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Boone, K.; Hayden, B.; Perlmutter, S. [Department of Physics, University of California Berkeley, 366 LeConte Hall, MC 7300, Berkeley, CA 94720-7300 (United States); Cooper, M. C. [Department of Physics and Astronomy, University of California, Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697 (United States); Demarco, R. [Departamento de Astronomía, Universidad de Concepción, Casilla 160-C, Concepción, Región del Biobío (Chile); Lidman, C., E-mail: noble@mit.edu [Australian Astronomical Observatory, 105 Delhi Road, North Ryde, NSW 2113 (Australia)

2017-06-20

We present ALMA CO (2–1) detections in 11 gas-rich cluster galaxies at z ∼ 1.6, constituting the largest sample of molecular gas measurements in z > 1.5 clusters to date. The observations span three galaxy clusters, derived from the Spitzer Adaptation of the Red-sequence Cluster Survey. We augment the >5 σ detections of the CO (2–1) fluxes with multi-band photometry, yielding stellar masses and infrared-derived star formation rates, to place some of the first constraints on molecular gas properties in z ∼ 1.6 cluster environments. We measure sizable gas reservoirs of 0.5–2 × 10{sup 11} M {sub ☉} in these objects, with high gas fractions ( f {sub gas}) and long depletion timescales ( τ ), averaging 62% and 1.4 Gyr, respectively. We compare our cluster galaxies to the scaling relations of the coeval field, in the context of how gas fractions and depletion timescales vary with respect to the star-forming main sequence. We find that our cluster galaxies lie systematically off the field scaling relations at z = 1.6 toward enhanced gas fractions, at a level of ∼4 σ , but have consistent depletion timescales. Exploiting CO detections in lower-redshift clusters from the literature, we investigate the evolution of the gas fraction in cluster galaxies, finding it to mimic the strong rise with redshift in the field. We emphasize the utility of detecting abundant gas-rich galaxies in high-redshift clusters, deeming them as crucial laboratories for future statistical studies.

The growth of Fe clusters over graphene/Cu(111)

International Nuclear Information System (INIS)

Takahashi, Keisuke

2015-01-01

The growth of Fe clusters up to nine atoms over graphene/Cu(111) is investigated within the density functional theory. Graphene is weakly physisorbed on Cu(111) through van der Waals force. The structures of Fe clusters over graphene/Cu(111) grow differently compared to gas-phase Fe clusters where Fe clusters are predicted to form towards a pyramid-like structure on graphene/Cu(111). The graphene is negatively charged upon the adsorption of Fe clusters as a result of charge transfer from Fe to graphene. Despite the fact that the electronic structure of graphene is affected by Fe clusters, magnetic moment of Fe clusters over graphene/Cu(111) remains relatively high. This suggests that graphene can be a potential substrate for supporting Fe clusters towards applications in magnetism and catalysis. (paper)

Cluster regression model and level fluctuation features of Van Lake, Turkey

Directory of Open Access Journals (Sweden)

Z. Şen

1999-02-01

Full Text Available Lake water levels change under the influences of natural and/or anthropogenic environmental conditions. Among these influences are the climate change, greenhouse effects and ozone layer depletions which are reflected in the hydrological cycle features over the lake drainage basins. Lake levels are among the most significant hydrological variables that are influenced by different atmospheric and environmental conditions. Consequently, lake level time series in many parts of the world include nonstationarity components such as shifts in the mean value, apparent or hidden periodicities. On the other hand, many lake level modeling techniques have a stationarity assumption. The main purpose of this work is to develop a cluster regression model for dealing with nonstationarity especially in the form of shifting means. The basis of this model is the combination of transition probability and classical regression technique. Both parts of the model are applied to monthly level fluctuations of Lake Van in eastern Turkey. It is observed that the cluster regression procedure does preserve the statistical properties and the transitional probabilities that are indistinguishable from the original data.Key words. Hydrology (hydrologic budget; stochastic processes · Meteorology and atmospheric dynamics (ocean-atmosphere interactions

Cluster regression model and level fluctuation features of Van Lake, Turkey

Directory of Open Access Journals (Sweden)

Z. Şen

Full Text Available Lake water levels change under the influences of natural and/or anthropogenic environmental conditions. Among these influences are the climate change, greenhouse effects and ozone layer depletions which are reflected in the hydrological cycle features over the lake drainage basins. Lake levels are among the most significant hydrological variables that are influenced by different atmospheric and environmental conditions. Consequently, lake level time series in many parts of the world include nonstationarity components such as shifts in the mean value, apparent or hidden periodicities. On the other hand, many lake level modeling techniques have a stationarity assumption. The main purpose of this work is to develop a cluster regression model for dealing with nonstationarity especially in the form of shifting means. The basis of this model is the combination of transition probability and classical regression technique. Both parts of the model are applied to monthly level fluctuations of Lake Van in eastern Turkey. It is observed that the cluster regression procedure does preserve the statistical properties and the transitional probabilities that are indistinguishable from the original data.

Key words. Hydrology (hydrologic budget; stochastic processes · Meteorology and atmospheric dynamics (ocean-atmosphere interactions

Study on the excited diatomic molecules of rare gas

International Nuclear Information System (INIS)

Kasama, Kunihiko; Arai, Shigeyoshi

1981-01-01

The study on the excited diatomic molecules of rare gas is presented. The absorption spectra, the mechanism of formation and attenuation and the reactions with other molecules are described. The excitation of rare gas was made by using a pulsed electron beam generator. The absorption of excited diatomic molecules was measured as the functions of time. Two absorption peaks were observed. The electron states of rare gases were estimated. The observed and calculated transition values were given for each peak. The absorption spectra of Ne change with time. The spectra of Ar do not change with time. Four and eleven absorption maxima were seen in the spectra of Kr and Xe, respectively. In the case of Ar, the thermal equilibrium existed. The constants of the production and attenuation rates were obtained as the functions of Ar gas pressure. In the case of Ne, there wad definitely the time dependence of absorption spectra. The attenuation constant was obtained for each transition between various vibration levels. It is necessary to consider the relaxation from high vibrational levels. The energy transfer between vibrational levels hardly occurred in Ne because the intervals are large. When there are other molecules, the attnuation was accelerated. (Kato, T.)

Ellis Van Creveld syndrome

Directory of Open Access Journals (Sweden)

Shilpy S

2007-05-01

Full Text Available Ellis Van Creveld syndrome is a rare disorder and is a form of short-limbed dwarfism. It is an autosomal recessive disorder characterized by tetrad of disproportionate dwarfism, post-axial polydactyly, ectodermal dysplasia and heart defects. This case report presents a classical case of a seven-year-old boy with Ellis Van Creveld syndrome presented with discrete clinical findings.

van der Waals forces in density functional theory: Perturbational long-range electron-interaction corrections

International Nuclear Information System (INIS)

Angyan, Janos G.; Gerber, Iann C.; Savin, Andreas; Toulouse, Julien

2005-01-01

Long-range exchange and correlation effects, responsible for the failure of currently used approximate density functionals in describing van der Waals forces, are taken into account explicitly after a separation of the electron-electron interaction in the Hamiltonian into short- and long-range components. We propose a 'range-separated hybrid' functional based on a local density approximation for the short-range exchange-correlation energy, combined with a long-range exact exchange energy. Long-range correlation effects are added by a second-order perturbational treatment. The resulting scheme is general and is particularly well adapted to describe van der Waals complexes, such as rare gas dimers

Saturation characteristics of liquid rare gas ionization chambers and recombination luminescence in liquid rare gas scintillation

International Nuclear Information System (INIS)

Takahashi, Tan; Konno, Satoshi; Kubota, Shinzo; Nakamoto, Jun; Miyajima, Mitsuhiro.

1978-01-01

From the saturation characteristics of liquid rare gases (Ar and Xe), the mean distance between electrons and ions. W-value, and the ratio of freely diffusion electrons were determined on the basis of the theory of Onsager. Their relationships with the scintillation due to recombination are also discussed. In the first part of this report, an analytic equation for the probability that an electron escapes from preferential recombination under the existence of an electric field is derived. The equation was then numerically solved with a computer code developed by Freeman. The adjusted parameters and the results of calculations for both Xe and Ar are presented together with the experimental results. Some discrepancy appeared between the analytical and the experimental results when the electric field was weak, and it is ascribable to the existence of the columnar (cluster) recombination and the effect of attachment due to the pulse method employed in the experiments. In the second part, the effect of electric field on the scintillation of liquid rare gases is considered, based on the theory of Onsager. (Aoki, K.)

Cross section determination for the higher ionization of rare gas ions by electron collisions

International Nuclear Information System (INIS)

Becker, R.; Frodl, R.; Klein, H.; Schmidt, W.; Clausnitzer, G.; Klinger, H.; Mueller, A.; Salzborn, E.; Fuchs, G.; Viehboeck, F.

1975-01-01

The higher ionization of rare gas ions is reported on, which were excited by an electron beam using a crossed-beam technique. A detector for the identification of metastable excited rare gas ions was developed. (WL) [de

Resources and geothermal heat in the Netherlands. Annual report 2011. An overview of exploration and exploitation activities and of underground gas storage; Delfstoffen en Aardwarmte in Nederland. Jaarverslag 2011. Een overzicht van opsporings- en winningsactiviteiten en van ondergrondse gasopslag

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-11-15

Traditionally, this annual report publishes the activities and results of the exploration and extraction of hydrocarbons in the Netherlands. Starting this year the report will be expanded with the exploration and extraction activities of rock salt and geothermal heat and the underground storage of resources (natural gas, nitrogen, CO2 and water). The first part of the annual report addresses the developments in the year 2011. This part also includes a prognosis for the extraction of natural gas for the next 25 years. Next, a number of tables illustrate developments in the field of licenses and exploration activities (seismic research and drilling) in 2011. The chapter on hydrocarbons is concluded with an overview of the extracted volumes of natural gas, condensate and petroleum and the gas flows in storage facilities. There are new chapters on exploration and extraction of rock salt and geothermal heat. Another new chapter addresses storage of resources. The second part of the annual report illustrates the situation per 1 January 2012 and the developments over the last decades in a number of overviews. The annexes, finally, include general maps of the situation as of 1 January 2012 [Dutch] Het Jaarverslag rapporteert over de activiteiten en resultaten van de opsporing en winning van koolwaterstoffen, steenzout en aardwarmte in Nederland. Daarnaast komt de ondergrondse opslag van stoffen (aardgas, stikstof, CO2 en water) aan de orde. Daarmee worden alle opsporings-, winnings- en opslagactiviteiten in Nederland en het Nederlandse deel van het Continentaal plat, vallend onder het regime van de Mijnbouwwet, gezamenlijk gerapporteerd. Het eerste deel van het jaarverslag gaat in op de ontwikkelingen in het jaar 2011. Zoals in voorgaande jaren richt dit deel zich op de opsporing, winning en de ondergrondse opslag van koolwaterstoffen. Dit betreft een overzicht van de veranderingen in de aardgas- en aardolievoorraden gedurende 2011 en de daaruit volgende situatie per 1

Ellis-van Creveld Syndrome: A Rare Clinical Report of Oral Rehabilitation by Interdisciplinary Approach

Directory of Open Access Journals (Sweden)

Talib Amin Naqash

2018-01-01

Full Text Available Ellis-van Creveld syndrome (EVC is a very rare genetic disorder that affects various tissues of ectodermal and mesodermal origin; patients with EVC present with typical oral deficiencies. The affected individuals are quite young at the time of oral evaluation. It is, therefore, important that these individuals are diagnosed and receive dental treatment at an early age for their physiologic and psychosocial well-being. Albeit there are numerous articles penned on the EVC, the treatise from an oral perspective is inadequate, covering only oral exhibitions and the preventive treatments. This article reviews the literature and serves as the first disquisition for oral rehabilitation of an EVC patient utilizing surgical, orthodontic, restorative, and prosthodontic management.

Dependence of energy per molecule on sputtering yields with reactive gas cluster ions

International Nuclear Information System (INIS)

Toyoda, Noriaki; Yamada, Isao

2010-01-01

Gas cluster ions show dense energy deposition on a target surface, which result in the enhancement of chemical reactions. In reactive sputtering with gas cluster ions, the energy per atom or molecule plays an important role. In this study, the average cluster size (N, the number of atoms or molecules in a cluster ion) was controlled; thereby the dependences of the energy per molecule on the sputtering yields of carbon by CO 2 cluster ions and that of Si by SF 6 /Ar mixed gas cluster ions were investigated. Large CO 2 cluster ions with energy per molecule of 1 eV showed high reactive sputtering yield of an amorphous carbon film. However, these ions did not cause the formation of large craters on a graphite surface. It is possible to achieve very low damage etching by controlling the energy per molecule of reactive cluster ions. Further, in the case of SF 6 /Ar mixed cluster ions, it was found that reactive sputtering was enhanced when a small amount of SF 6 gas (∼10%) was mixed with Ar. The reactive sputtering yield of Si by one SF 6 molecule linearly increased with the energy per molecule.

Molecular Gas Reservoirs in Cluster Galaxies at z = 1.46

Science.gov (United States)

Hayashi, Masao; Tadaki, Ken-ichi; Kodama, Tadayuki; Kohno, Kotaro; Yamaguchi, Yuki; Hatsukade, Bunyo; Koyama, Yusei; Shimakawa, Rhythm; Tamura, Yoichi; Suzuki, Tomoko L.

2018-04-01

We present molecular gas reservoirs of 18 galaxies associated with the XMMXCS J2215.9–1738 cluster at z = 1.46. From Band 7 and Band 3 data of the Atacama Large Millimeter/submillimeter Array, we detect dust continuum emission at 870 μm and the CO J = 2–1 emission line from 8 and 17 member galaxies, respectively, within a clustercentric radius of R 200. The molecular gas masses derived from the CO and/or dust continuum luminosities show that the fraction of molecular gas mass and the depletion timescale for the cluster galaxies are larger than expected from the scaling relations of molecular gas on stellar mass and offset from the main sequence of star-forming galaxies in general fields. The galaxies closer to the cluster center in terms of both projected position and accretion phase seem to show a larger deviation from the scaling relations. We speculate that the environment of the galaxy cluster helps feed the gas through inflow to the member galaxies and reduce the efficiency of star formation. The stacked Band 3 spectrum of 12 quiescent galaxies with M stellar ∼ 1011 M ⊙ within 0.5R 200 shows no detection of a CO emission line, giving the upper limit of molecular gas mass and molecular gas fraction to be ≲1010 M ⊙ and ≲10%, respectively. Therefore, the massive galaxies in the cluster core quench the star formation activity while consuming most of the gas reservoirs.

Structures, stabilities, and electronic properties for rare-earth lanthanum doped gold clusters

International Nuclear Information System (INIS)

Zhao, Ya-Ru

2015-01-01

The structures, stabilities, and electronic properties of rare-earth lanthanum doped gold La 2 Au n (n = 1-9) and pure gold Au n (n ≤ 11) clusters have been investigated by using density functional theory. The optimized geometries show that the lowest energy structures of La 2 Au n clusters favour the 3D structure at n ≥ 3. The lanthanum atoms can strongly enhance the stabilities of gold clusters and tend to occupy the most highly coordinated position. By analysing the gap, vertical ionization potential, and chemical hardness, it is found that the La 2 Au 6 isomer possesses higher stability for small-sized La 2 Au n clusters (n = 1-9). The charges in the La 2 Au n clusters transfer from La atoms to the Au n host. In addition, Wiberg bond indices analysis reveals that the intensity of different bonds of La 2 Au n clusters exhibits a sequence of La-La bond > La-Au bond > Au-Au bond.

De Haas-van Alphen effect of a two-dimensional ultracold atomic gas

Science.gov (United States)

Farias, B.; Furtado, C.

2016-01-01

In this paper, we show how the ultracold atom analogue of the two-dimensional de Haas-van Alphen effect in electronic condensed matter systems can be induced by optical fields in a neutral atomic system. The interaction between the suitable spatially varying laser fields and tripod-type trapped atoms generates a synthetic magnetic field which leads the particles to organize themselves in Landau levels. Initially, with the atomic gas in a regime of lowest Landau level, we display the oscillatory behaviour of the atomic energy and its derivative with respect to the effective magnetic field (B) as a function of 1/B. Furthermore, we estimate the area of the Fermi circle of the two-dimensional atomic gas.

Clustering in a quark gas

International Nuclear Information System (INIS)

Welke, G.M.; Heiss, W.D.

1986-01-01

In an infinite one-dimensional quark gas it is shown that a static color force, which increases at large distance, leads to a density fluctuation in the ground state. A self-consistent mean field can only be found for an effectively attractive quark-quark interaction that increases less than linearly at large distances. For a fixed coupling constant, the clustering disappears at high quark density

Binding energy of large icosahedral and cuboctahedral Lennard-Jones clusters

International Nuclear Information System (INIS)

Northby, J.A.; Xie, J.

1989-01-01

It is widely believed that the lowest energy configurations for small rare gas clusters have icosahedral symmetry. This contrasts with the bulk crystal structures which have cuboctahedral fcc symmetry. It is of interest to understand the transition between this finite and bulk behavior. To model this transition in rare gas clusters we have undertaken optimization studies within the Lennard-Jones pair potential model. Using a combination of Monte Carlo and Partan Search optimization methods, the lowest energy relaxed structures of Lennard-Jones clusters having icosahedral and cuboctahedral symmetry were found. Studies were performed for complete shell clusters ranging in size from one shell having 13 atoms to 14 shells having 10,179 atoms. It was found that the icosahedral structures are lower in energy than the cuboctahedral structures for cluster sizes having 13 shells or fewer. Additional studies were performed using the more accurate Aziz-Chen [HFD-C] pair potential parameterized for argon. The conclusions appear to be relatively insensitive to the form of the potential. (orig.)

The present status of rare gas release control

International Nuclear Information System (INIS)

Yamamoto, Hiroshi

1974-01-01

Of the rare gases Ar, Kr and Xe released from nuclear facilities, the problem of release control can be confined to 41 Ar, 85 Kr and 133 Xe. The cases of the latter two are described, as 41 Ar is not much significant. 133 Xe, having relatively short half-life, can be dealt sufficiently by holding-up in case of light water reactors. 85 Kr of long half-life must be removed : the methods are low temperature adsorption, liquefaction distillation, absorption and diaphragm method. As for future problem, there is disposal of concentrated rare gas. (Mori, K.)

Gas stripping and mixing in galaxy clusters: a numerical comparison study

Science.gov (United States)

Heß, Steffen; Springel, Volker

2012-11-01

The ambient hot intrahalo gas in clusters of galaxies is constantly fed and stirred by infalling galaxies, a process that can be studied in detail with cosmological hydrodynamical simulations. However, different numerical methods yield discrepant predictions for crucial hydrodynamical processes, leading for example to different entropy profiles in clusters of galaxies. In particular, the widely used Lagrangian smoothed particle hydrodynamics (SPH) scheme is suspected to strongly damp fluid instabilities and turbulence, which are both crucial to establish the thermodynamic structure of clusters. In this study, we test to which extent our recently developed Voronoi particle hydrodynamics (VPH) scheme yields different results for the stripping of gas out of infalling galaxies and for the bulk gas properties of cluster. We consider both the evolution of isolated galaxy models that are exposed to a stream of intracluster medium or are dropped into cluster models, as well as non-radiative cosmological simulations of cluster formation. We also compare our particle-based method with results obtained with a fundamentally different discretization approach as implemented in the moving-mesh code AREPO. We find that VPH leads to noticeably faster stripping of gas out of galaxies than SPH, in better agreement with the mesh-code than with SPH. We show that despite the fact that VPH in its present form is not as accurate as the moving mesh code in our investigated cases, its improved accuracy of gradient estimates makes VPH an attractive alternative to SPH.

Slingshot mechanism for clusters: Gas density regulates star density in the Orion Nebula Cluster (M42)

Science.gov (United States)

Stutz, Amelia M.

2018-02-01

We characterize the stellar and gas volume density, potential, and gravitational field profiles in the central ∼0.5 pc of the Orion Nebula Cluster (ONC), the nearest embedded star cluster (or rather, protocluster) hosting massive star formation available for detailed observational scrutiny. We find that the stellar volume density is well characterized by a Plummer profile ρstars(r) = 5755 M⊙ pc- 3 (1 + (r/a)2)- 5/2, where a = 0.36 pc. The gas density follows a cylindrical power law ρgas(R) = 25.9 M⊙ pc- 3 (R/pc)- 1.775. The stellar density profile dominates over the gas density profile inside r ∼ 1 pc. The gravitational field is gas-dominated at all radii, but the contribution to the total field by the stars is nearly equal to that of the gas at r ∼ a. This fact alone demonstrates that the protocluster cannot be considered a gas-free system or a virialized system dominated by its own gravity. The stellar protocluster core is dynamically young, with an age of ∼2-3 Myr, a 1D velocity dispersion of σobs = 2.6 km s-1, and a crossing time of ∼0.55 Myr. This time-scale is almost identical to the gas filament oscillation time-scale estimated recently by Stutz & Gould. This provides strong evidence that the protocluster structure is regulated by the gas filament. The protocluster structure may be set by tidal forces due to the oscillating filamentary gas potential. Such forces could naturally suppress low density stellar structures on scales ≳ a. The analysis presented here leads to a new suggestion that clusters form by an analogue of the 'slingshot mechanism' previously proposed for stars.

Van Allen Probes, THEMIS, GOES, and Cluster Observations of EMIC Waves, ULF Pulsations, and an Electron Flux Dropout

Science.gov (United States)

Sigsbee, K.; Kletzing, C. A.; Smith, C. W.; Macdowall, R.; Spence, H.; Reeves, G.; Blake, J. B.; Baker, D. N.; Green, J. C.; Singer, H. J.;

Genetics Home Reference: van der Woude syndrome

Science.gov (United States)

... What is the prognosis of a genetic condition? Genetic and Rare Diseases Information Center Frequency Van der Woude syndrome is believed to occur in 1 in 35,000 to 1 in 100,000 people, based on data from Europe and Asia. Van der Woude syndrome ...

Dissymmetry effects on the laser spectroscopy of supersonically expanded rare gas/chiral arene heteroclusters.

Science.gov (United States)

Filippi, Antonello; Giardini, Anna; Marcantoni, Enrico; Paladini, Alessandra; Piccirillo, Susanna; Renzi, Gabriele; Rondino, Flaminia; Roselli, Graziella; Satta, Mauro; Speranza, Maurizio

2007-04-14

The R2PI-TOF spectra of supersonically expanded rare gas/chiral arene heteroclusters have been rationalized in terms of the distortion of the pi-electron density reflecting the different dipole and quadrupole momenta induced in the rare gas atoms by interaction with the opposite pi-faces of the chiral arene itself.

Working paper Green Gas. Overview of policy issues on Green Gas; Werkdocument Groen Gas. Overzicht Beleidsvraagstukken Groen Gas

Energy Technology Data Exchange (ETDEWEB)

Dumont, M.

2012-07-15

Early 2010, the interdepartmental Accelerator Team Green Gas was established which deals with policy issues in the field of Green Gas. This working document reflects the current state of affairs. Via the website www.groengas.nl new versions will be made available on a regular basis [Dutch] Begin 2010 is het interdepartementale Versnellerteam Groen Gas opgericht dat zich bezighoudt met vraagstukken op het gebied van Groen Gas die op het terrein van de rijksoverheid liggen. Dit werkdocument geeft de huidige stand van zaken weer. Via www.groengas.nl komen geregeld nieuwe versies beschikbaar.

A Fault Diagnosis Approach for Gas Turbine Exhaust Gas Temperature Based on Fuzzy C-Means Clustering and Support Vector Machine

Directory of Open Access Journals (Sweden)

Zhi-tao Wang

2015-01-01

Full Text Available As an important gas path performance parameter of gas turbine, exhaust gas temperature (EGT can represent the thermal health condition of gas turbine. In order to monitor and diagnose the EGT effectively, a fusion approach based on fuzzy C-means (FCM clustering algorithm and support vector machine (SVM classification model is proposed in this paper. Considering the distribution characteristics of gas turbine EGT, FCM clustering algorithm is used to realize clustering analysis and obtain the state pattern, on the basis of which the preclassification of EGT is completed. Then, SVM multiclassification model is designed to carry out the state pattern recognition and fault diagnosis. As an example, the historical monitoring data of EGT from an industrial gas turbine is analyzed and used to verify the performance of the fusion fault diagnosis approach presented in this paper. The results show that this approach can make full use of the unsupervised feature extraction ability of FCM clustering algorithm and the sample classification generalization properties of SVM multiclassification model, which offers an effective way to realize the online condition recognition and fault diagnosis of gas turbine EGT.

HM{sup +}–RG complexes (M = group 2 metal; RG = rare gas): Physical vs. chemical interactions

Energy Technology Data Exchange (ETDEWEB)

Harris, Joe P.; Dodson, Hannah; Wright, Timothy G., E-mail: Tim.Wright@nottingham.ac.uk [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Breckenridge, W. H. [Department of Chemistry, University of Utah, Salt Lake City, Utah 84112 (United States)

2015-04-21

Previous work on the HM{sup +}–He complexes (M = Be–Ra) has been extended to the cases of the heavier rare gas atoms, HM{sup +}–RG (RG = Ne–Rn). Optimized geometries and harmonic vibrational frequencies have been calculated using MP2 theory and quadruple-ζ quality basis sets. Dissociation energies for the loss of the rare gas atom have been calculated at these optimized geometries using coupled cluster with single and double excitations and perturbative triples, CCSD(T)theory, extrapolating interaction energies to the basis set limit. Comparisons are made between the present data and the previously obtained helium results, as well as to those of the bare HM{sup +} molecules; furthermore, comparisons are made to the related M{sup +}–RG and M{sup 2+}–RG complexes. Partial atomic charge analyses have also been undertaken, and these used to test a simple charge-induced dipole model. Molecular orbital diagrams are presented together with contour plots of the natural orbitals from the quadratic configuration with single and double excitations (QCISD) density. The conclusion is that the majority of these complexes are physically bound, with very little sharing of electron density; however, for M = Be, and to a lesser extent M = Mg, some evidence for chemical effects is seen in HM{sup +}–RG complexes involving RG atoms with the higher atomic numbers.

Monitoring gas quality green gas feeding in; Monitoring gaskwaliteit groengasinvoeding

Energy Technology Data Exchange (ETDEWEB)

Holstein, J. [DNV KEMA Energy and Sustainability, Arnhem (Netherlands); Polman, E. [Kiwa Technology, Apeldoorn (Netherlands)

2013-04-15

Due to the growing number of green gas facilities in the Netherlands more practical knowledge is collected about the production and injection of green gas. Also there was the need to gather data about more practical experiences and knowledge about the gas quality, the performance of gas cleaning and gas treatment systems, as well the integration of green gas in the gas infrastructure. In addition to this, there is a need to get insight in the safety aspects of green gas injection. In order to comply this demand, DNV KEMA en Kiwa Technology measured the quality parameters continuously between June 2012 en January 2013 (three weeks) and discontinuously (gas samples) of green gas at eight production facilities. The measurements have been performed at designated places and are independent from the measurements of the biomethane producer. In order to be sure that the results of DNV KEMA and Kiwa are comparable, a combined measurement program was executed. It results in uniformity for all the measured values: the differences are within the uncertainty level for each component. During the measurement period of three weeks, the gas quality parameters were compared to specifications, written down in the national regulations for the transport and the distribution grid respectively [Dutch] Door het groeiend aantal groengasinvoedingen in Nederland wordt steeds meer praktijkkennis verzameld. Er dient meer praktijkkennis te worden verzameld over de chemische gaskwaliteit, prestaties van de gasreiniging- en gasopwaardering en de wijze van inpassing in de bestaande infrastructuur. Daarnaast is het wenselijk om inzicht te verkrijgen in de veiligheid van groengasinvoeding. Daarop is de groengaskwaliteit op acht locaties over een periode van drie weken continu en discontinu gemeten tussen juni 2012 en januari 2013. De metingen zijn uitgevoerd op een aangewezen plaats door de netbeheerder en staan los van de metingen van de invoeders zelf. Voor het waarborgen van de uniformiteit van

Kinetic analysis of rare gas metastable production and optically pumped Xe lasers

Science.gov (United States)

Demyanov, A. V.; Kochetov, I. V.; Mikheyev, P. A.; Azyazov, V. N.; Heaven, M. C.

2018-01-01

Optically pumped all-rare-gas lasers use metastable rare gas atoms as the lasing species in mixtures with He or Ar buffer gas. The metastables are generated in a glow discharge, and we report model calculations for the optimal production of Ne*, Ar*, Kr* and Xe*. Discharge efficiency was estimated by solving the Boltzmann equation. Laser efficiency, gain and output power of the CW optically pumped Xe laser were assessed as functions of heavier rare gas content, pressure, optical pump intensity and the optical path length. It was found that, for efficient operation the heavier rare gas content has to be of the order of one percent or less, and the total pressure—in the range 0.3-1.5 atm. Output power and specific discharge power increase approximately linearly with pump intensity over the output range from 300-500 W cm-2. Ternary mixtures Xe:Ar:He were found to be the most promising. Total laser efficiency was found to be nearly the same for pumping the 2p8 or 2p9 state, reaching 61%-70% for a pump intensity of ~720 W cm-2 when the Xe fraction was in the range 0.001 ÷ 0.01 and Ar fraction—0.1 ÷ 0.5. However, when the 2p8 state was pumped, the maximum total efficiency occurred at larger pressures than for pumping of the 2p9 state. The discharge power density required to sustain a sufficient Xe* number density was in the range of tens of watts per cubic centimeter for 50% Ar in the mixture.

A cluster dynamics study of fission gases in uranium dioxide

International Nuclear Information System (INIS)

Skorek, Richard

2013-01-01

During in-pile irradiation of nuclear fuels a lot of rare gases are produced, mainly xenon and krypton. The behaviour of these highly insoluble fission gases may lead to an additional load of the cladding, which may have detrimental safety consequences. For these reasons, fission gas behaviour (diffusion and clustering) has been extensively studied for years.In this work, we present an application of Cluster Dynamics to address the behaviour of fission gases in UO_2 which simultaneously describes changes in rare gas atom and point defect concentrations in addition to the bubble size distribution. This technique, applied to Kr implanted and annealed samples, yields a precise interpretation of the release curves and helps justifying the estimation of the Kr diffusion coefficient, which is a data very difficult to obtain due to the insolubility of the gas. (author) [fr

Magnetic behavior of Van Vleck ions and an electron gas interacting by exchange

International Nuclear Information System (INIS)

Palermo, L.; Silva, X.A. da.

1980-01-01

The magnetic behavior of a model in which Van Vleck ions, under the action of a crystal field, interacting by exchange with an electron gas is investigated. The condition of onset of ferromagnetism and the behavior of the critical temperature, band and ionic magnetizations (and susceptibilities) versus temperature, as a function of the band width, exchange interaction and the crystal field splitting energy parameters are obtained within an approximation equivalent to a molecular field formulation. (Author) [pt

The nature and role of the gold-krypton interactions in small neutral gold clusters.

Science.gov (United States)

Mancera, Luis A; Benoit, David M

2015-03-26

We investigate the nature and role of krypton embedding in small neutral gold clusters. For some of these clusters, we observe a particular site-dependent character of the Kr binding that does not completely follow the criterion of binding at low-coordinated sites, widely accepted for interaction of a noble gas with closed-shell metal systems such as metal surfaces. We aim at understanding the effect of low dimensionality and open-shell electronic structure of the odd-numbered clusters on the noble gas-metal cluster interaction. First, we investigate the role of attractive and repulsive forces, and the frontier molecular orbitals. Second, we investigate the Au-Kr interaction in terms of reactivity and bonding character. We use a reactivity index derived from Fukui formalism, and criteria provided by the electron localization function (ELF), in order to classify the type of bonding. We carry out this study on the minimum energy structures of neutral gold clusters, as obtained using pseudo potential plane-wave density functional theory (DFT). A model is proposed that includes the effect of attractive electrostatic, van der Waals and repulsive forces, together with effects originating from orbital overlap. This satisfactorily explains minimum configurations of the noble gas-gold cluster systems, the site preference of the noble gas atoms, and changes in electronic properties.

Regionale clustering biologische landbouw; Randvoorwaarde voor groei?

NARCIS (Netherlands)

Stokkers, R.; Braker, M.; Lenssinck, F.; Waal, van der B.H.C.

2005-01-01

Onderzoek naar het effect van regionale clustering op de groei van de biologische landbouw in Nederland. Op basis van literatuuronderzoek en interviews met woordvoerders van regionale samenwerkingsverbanden worden die activiteiten in de biologische landbouw onderscheiden, waarbij regionale

Photochemistry of xenon-halogen Van der Waals complexes (X2 = Cl2, Br2, I2): evidence for the intermediate states in the (Xe-X2)*→ XeX* + X reaction

International Nuclear Information System (INIS)

Boivineau, Michel

1987-01-01

This research thesis addresses the reactivity of excited states of xenon-halogen Van der Waals complexes (Cl 2 , Br 2 , I 2 ) submitted to a multi-photonic excitation. The objective of this study is, by means of a specific experimental approach, to highlight the R*+ X 2 *- to better understand the reaction mechanism, and to study the reactivity of rare gas/halogen systems depending on the halogen nature. After having reported a bibliographical study on each studied system, the author describes the experimental system, reports and discusses experimental results obtained on the different complex systems (chlorine-, bromine- or iodine-based). He finally comments a possible and original application of these works in the development of an excimer laser with a new active medium (the rare gas/halogen Van der Waals complex) which would allow a continuous operation and an easy discharge production [fr

Dynamical evolution of stars and gas of young embedded stellar sub-clusters

Science.gov (United States)

Sills, Alison; Rieder, Steven; Scora, Jennifer; McCloskey, Jessica; Jaffa, Sarah

2018-03-01

We present simulations of the dynamical evolution of young embedded star clusters. Our initial conditions are directly derived from X-ray, infrared, and radio observations of local systems, and our models evolve both gas and stars simultaneously. Our regions begin with both clustered and extended distributions of stars, and a gas distribution which can include a filamentary structure in addition to gas surrounding the stellar subclusters. We find that the regions become spherical, monolithic, and smooth quite quickly, and that the dynamical evolution is dominated by the gravitational interactions between the stars. In the absence of stellar feedback, the gas moves gently out of the centre of our regions but does not have a significant impact on the motions of the stars at the earliest stages of cluster formation. Our models at later times are consistent with observations of similar regions in the local neighbourhood. We conclude that the evolution of young proto-star clusters is relatively insensitive to reasonable choices of initial conditions. Models with more realism, such as an initial population of binary and multiple stars and ongoing star formation, are the next step needed to confirm these findings.

Spectral blueshifts in laser light scattered from argon-gas-cluster plasmas

International Nuclear Information System (INIS)

Singhal, H.; Arora, V.; Naik, P.A.; Gupta, P.D.

2005-01-01

An experimental study is presented on scattering of laser light from argon gas clusters irradiated by multipicosecond Nd:glass laser pulses at moderate intensity of 10 15 W/cm 2 . Space-resolved side-scattered laser light has a predominantly blueshifted and broadened spectrum (up to ∼8 nm). The scattered signal intensity and average blueshift exhibit a marked dependence on the backing pressure of the gas. The results are explained by self-phase modulation of the laser radiation due to changing polarizability as the heated clusters pass through resonance at 3 times the critical density during which intense absorption and scattering occurs. The observed blueshift may be useful in diagnostics of this important phase of laser-cluster interactions

On the electronic and geometrical structures of small atomic clusters

International Nuclear Information System (INIS)

Malrieu, J.P.; Maynau, D.

1987-01-01

This paper recalls the main challenges and difficulties of the theoretical study of small clusters of atoms. It briefly summarizes some informations concerning rare-gas clusters and clusters of normal elements such as C or Si. The main discussion is devoted to the small clusters of the simplest metal (Li), comparing the agreement and discrepancies between two crude models - the jellium model and the tight-binding one - with the most refined ab initio calculations. 28 refs

Isothermality of the gas in the Coma cluster

International Nuclear Information System (INIS)

Hughes, J.P.; Yamashita, K.; Okumura, Y.; Tsunemi, H.; Matsuoka, M.

1988-01-01

The high-quality X-ray spectrum of the Coma cluster observed by the Japanese satelite Tenma in conjunction with imaging data from the Einstein Observatory was used to explore the temperature distribution of the cluster gas. It is found that pure polytropic models are inadequate to describe this temperature distribution. Instead, a hybrid model is proposed consisting of a central isothermal region surrounded by a polytropic distribution. It is shown that as much as 75 percent of the global emission may come from the isothermal component. 30 references

Nanocomposite metal/plasma polymer films prepared by means of gas aggregation cluster source

Energy Technology Data Exchange (ETDEWEB)

Polonskyi, O.; Solar, P.; Kylian, O.; Drabik, M.; Artemenko, A.; Kousal, J.; Hanus, J.; Pesicka, J.; Matolinova, I. [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague 8 (Czech Republic); Kolibalova, E. [Tescan, Libusina trida 21, 632 00 Brno (Czech Republic); Slavinska, D. [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague 8 (Czech Republic); Biederman, H., E-mail: bieder@kmf.troja.mff.cuni.cz [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague 8 (Czech Republic)

2012-04-02

Nanocomposite metal/plasma polymer films have been prepared by simultaneous plasma polymerization using a mixture of Ar/n-hexane and metal cluster beams. A simple compact cluster gas aggregation source is described and characterized with emphasis on the determination of the amount of charged clusters and their size distribution. It is shown that the fraction of neutral, positively and negatively charged nanoclusters leaving the gas aggregation source is largely influenced by used operational conditions. In addition, it is demonstrated that a large portion of Ag clusters is positively charged, especially when higher currents are used for their production. Deposition of nanocomposite Ag/C:H plasma polymer films is described in detail by means of cluster gas aggregation source. Basic characterization of the films is performed using transmission electron microscopy, ultraviolet-visible and Fourier-transform infrared spectroscopies. It is shown that the morphology, structure and optical properties of such prepared nanocomposites differ significantly from the ones fabricated by means of magnetron sputtering of Ag target in Ar/n-hexane mixture.

A numerical study of spin-dependent organization of alkali-metal atomic clusters using density-functional method

International Nuclear Information System (INIS)

Liu Xuan; Ito, Haruhiko; Torikai, Eiko

2012-01-01

We calculate the different geometric isomers of spin clusters composed of a small number of alkali-metal atoms using the UB3LYP density-functional method. The electron density distribution of clusters changes according to the value of total spin. Steric structures as well as planar structures arise when the number of atoms increases. The lowest spin state is the most stable and Li n , Na n , K n , Rb n , and Cs n with n = 2–8 can be formed in higher spin states. In the highest spin state, the preparation of clusters depends on the kind and the number of constituent atoms. The interaction energy between alkali-metal atoms and rare-gas atoms is smaller than the binding energy of spin clusters. Consequently, it is possible to self-organize the alkali-metal-atom clusters on a non-wetting substrate coated with rare-gas atoms.

A numerical study of spin-dependent organization of alkali-metal atomic clusters using density-functional method

Energy Technology Data Exchange (ETDEWEB)

Liu Xuan, E-mail: liu.x.ad@m.titech.ac.jp; Ito, Haruhiko [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology (Japan); Torikai, Eiko [Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi (Japan)

2012-08-15

We calculate the different geometric isomers of spin clusters composed of a small number of alkali-metal atoms using the UB3LYP density-functional method. The electron density distribution of clusters changes according to the value of total spin. Steric structures as well as planar structures arise when the number of atoms increases. The lowest spin state is the most stable and Li{sub n}, Na{sub n}, K{sub n}, Rb{sub n}, and Cs{sub n} with n = 2-8 can be formed in higher spin states. In the highest spin state, the preparation of clusters depends on the kind and the number of constituent atoms. The interaction energy between alkali-metal atoms and rare-gas atoms is smaller than the binding energy of spin clusters. Consequently, it is possible to self-organize the alkali-metal-atom clusters on a non-wetting substrate coated with rare-gas atoms.

Van der Waals potentials between metal clusters and helium atoms obtained with density functional theory and linear response methods

International Nuclear Information System (INIS)

Liebrecht, M.

2014-01-01

The importance of van der Waals interactions in many diverse research fields such as, e. g., polymer science, nano--materials, structural biology, surface science and condensed matter physics created a high demand for efficient and accurate methods that can describe van der Waals interactions from first principles. These methods should be able to deal with large and complex systems to predict functions and properties of materials that are technologically and biologically relevant. Van der Waals interactions arise due to quantum mechanical correlation effects and finding appropriate models an numerical techniques to describe this type of interaction is still an ongoing challenge in electronic structure and condensed matter theory. This thesis introduces a new variational approach to obtain intermolecular interaction potentials between clusters and helium atoms by means of density functional theory and linear response methods. It scales almost linearly with the number of electrons and can therefore be applied to much larger systems than standard quantum chemistry techniques. The main focus of this work is the development of an ab-initio method to account for London dispersion forces, which are purely attractive and dominate the interaction of non--polar atoms and molecules at large distances. (author) [de

Segmentation of Residential Gas Consumers Using Clustering Analysis

Directory of Open Access Journals (Sweden)

Marta P. Fernandes

2017-12-01

Full Text Available The growing environmental concerns and liberalization of energy markets have resulted in an increased competition between utilities and a strong focus on efficiency. To develop new energy efficiency measures and optimize operations, utilities seek new market-related insights and customer engagement strategies. This paper proposes a clustering-based methodology to define the segmentation of residential gas consumers. The segments of gas consumers are obtained through a detailed clustering analysis using smart metering data. Insights are derived from the segmentation, where the segments result from the clustering process and are characterized based on the consumption profiles, as well as according to information regarding consumers’ socio-economic and household key features. The study is based on a sample of approximately one thousand households over one year. The representative load profiles of consumers are essentially characterized by two evident consumption peaks, one in the morning and the other in the evening, and an off-peak consumption. Significant insights can be derived from this methodology regarding typical consumption curves of the different segments of consumers in the population. This knowledge can assist energy utilities and policy makers in the development of consumer engagement strategies, demand forecasting tools and in the design of more sophisticated tariff systems.

Hot gas in clusters of galaxies, cosmic microwave background radiation and cosmology

CERN Multimedia

CERN. Geneva

2018-01-01

Presence of the hot (kTe ~ 3 - 10 KeV) rarefied gas in the clusters of galaxies (most massive gravitationally bound objects in the Universe) leads to the appearance of  "shadows"  in the angular distribution of the Cosmic Microwave Background (CMB) Radiation and permits to measure the peculiar velocities of these clusters relative to the unique coordinate frame where CMB is isotropic. I plan to describe the physics leading to these observational effects. Planck spacecraft, ground based South Pole and Atacama Cosmology Telescopes discovered recently more than two thousand of unknown before Clusters of Galaxies at high redshifts detecting these "shadows" and traces of kinematic effect, demonstrating the correlation of the hot gas velocities with mass concentrations on large scales. Giant ALMA interferometer in Atacama desert resolved recently strong shocks between merging clusters of galaxies. Newly discovered clusters of galaxies permit to study the rate of growth of the large scale structur...

The self limiting effect of hydrogen cluster in gas jet under liquid nitrogen temperature

International Nuclear Information System (INIS)

Han Jifeng; Yang Chaowen; Miao Jingwei; Fu Pengtao; Luo Xiaobing; Shi Miangong

2010-01-01

The generation of hydrogen clusters in gas jet is tested using the Rayleigh scattering method under liquid nitrogen temperature of 79 K. The self limiting effect of hydrogen cluster is studied and it is found that the cluster formation is greatly affected by the number of expanded molecules. The well designed liquid nitrogen cold trap ensured that the hydrogen cluster would keep maximum size for maximum 15 ms during one gas jet. The scattered light intensity exhibits a power scaling on the backing pressure ranging from 5 to 48 bar with the power value of 4.1.

Fault Detection Using the Clustering-kNN Rule for Gas Sensor Arrays

Directory of Open Access Journals (Sweden)

Jingli Yang

2016-12-01

Full Text Available The k-nearest neighbour (kNN rule, which naturally handles the possible non-linearity of data, is introduced to solve the fault detection problem of gas sensor arrays. In traditional fault detection methods based on the kNN rule, the detection process of each new test sample involves all samples in the entire training sample set. Therefore, these methods can be computation intensive in monitoring processes with a large volume of variables and training samples and may be impossible for real-time monitoring. To address this problem, a novel clustering-kNN rule is presented. The landmark-based spectral clustering (LSC algorithm, which has low computational complexity, is employed to divide the entire training sample set into several clusters. Further, the kNN rule is only conducted in the cluster that is nearest to the test sample; thus, the efficiency of the fault detection methods can be enhanced by reducing the number of training samples involved in the detection process of each test sample. The performance of the proposed clustering-kNN rule is fully verified in numerical simulations with both linear and non-linear models and a real gas sensor array experimental system with different kinds of faults. The results of simulations and experiments demonstrate that the clustering-kNN rule can greatly enhance both the accuracy and efficiency of fault detection methods and provide an excellent solution to reliable and real-time monitoring of gas sensor arrays.

Fault Detection Using the Clustering-kNN Rule for Gas Sensor Arrays

Science.gov (United States)

Yang, Jingli; Sun, Zhen; Chen, Yinsheng

2016-01-01

The k-nearest neighbour (kNN) rule, which naturally handles the possible non-linearity of data, is introduced to solve the fault detection problem of gas sensor arrays. In traditional fault detection methods based on the kNN rule, the detection process of each new test sample involves all samples in the entire training sample set. Therefore, these methods can be computation intensive in monitoring processes with a large volume of variables and training samples and may be impossible for real-time monitoring. To address this problem, a novel clustering-kNN rule is presented. The landmark-based spectral clustering (LSC) algorithm, which has low computational complexity, is employed to divide the entire training sample set into several clusters. Further, the kNN rule is only conducted in the cluster that is nearest to the test sample; thus, the efficiency of the fault detection methods can be enhanced by reducing the number of training samples involved in the detection process of each test sample. The performance of the proposed clustering-kNN rule is fully verified in numerical simulations with both linear and non-linear models and a real gas sensor array experimental system with different kinds of faults. The results of simulations and experiments demonstrate that the clustering-kNN rule can greatly enhance both the accuracy and efficiency of fault detection methods and provide an excellent solution to reliable and real-time monitoring of gas sensor arrays. PMID:27929412

Using the van der Waals broadening of the spectral atomic lines to measure the gas temperature of an argon microwave plasma at atmospheric pressure

International Nuclear Information System (INIS)

Yubero, C.; Dimitrijevic, M.S.; Garcia, M.C.; Calzada, M.D.

2007-01-01

The ro-vibrational emission spectra of the molecular species are usually used to measure the gas temperature of a discharge at atmospheric pressure. However, under some experimental conditions, it is difficult to detect them. In order to overcome this difficulty and obtain the temperature, there are methods based on the relation between the gas temperature and the van der Waals broadening of argon atomic spectral lines with a Stark contribution negligible. In this work, we propose a method based on this relation but for lines with a Stark broadening comparable with the van der Waals one

Heat removal in gas-cooled fuel rod clusters

International Nuclear Information System (INIS)

Rehme, K.

1975-01-01

For a thermo- and fluid-dynamic analysis of fuel rod cluster subchannels for gas-cooled breeder reactors, the following values must be verified: a) friction coefficient as flow parameter; b) Stanton number as heat transfer parameter; c) influence of spacers on friction coefficient and Stanton number; d) heat and mass exchange between subchannels with different temperatures. These parameters are established by combining results of single experiments and of integral experiments. Mention is made of further studies to be performed in order to determine the heat removal from gas-cooled fast breeder fuel elements. (HR) [de

Emission of greenhouse gases from sewage installations; Emissies van broeikasgassen van rwzi's

Energy Technology Data Exchange (ETDEWEB)

Van Voorthuizen, E.; Van Leusden, M.; Visser, A.; Kruit, J. [Royal Haskoning, Amersfoort (Netherlands); Kampschreur, M.; Van Dongen, U.; Van Loosdrecht, M. [Technische Universiteit Delft TUD, Delft (Netherlands)

2010-03-15

Emissions of greenhouse gases (CO2, CH4, N2O) from wastewater treatment plants (WWTPs) are monitored. The emission of CO2 from waste water treatment plants (WWTPs) is related to the use of electricity, natural gas or other fossil fuels. The amount and origin of the emission of CH4 and N2O, however, is unknown. Presently emission factors from the IPCC (Intergovernmental Panel on Climate Change) and the Dutch Ministry of Housing, Spatial Planning and the Environment (VROM) are used to estimate those emissions. The aim of the study on the title subject was to determine the level of N2O and CH4 emission from Dutch WWTPs to understand the accuracy of the existing emission factors. In this way an estimation of the total greenhouse gas emission from a Dutch WWTP can be made. The emission of N2O and CH4 was measured at three WWTPs in the Netherlands: Papendrecht, Kortenoord and Kralingseveer [Dutch] In deze studie zijn de indirecte en directe emissies van broeikasgassen (CO2, CH4 en N2O) van rwzi's in kaart gebracht aan de hand van metingen. De resultaten hebben aanleiding gegeven voor een vervolgonderzoek waarbij onder meer kennis wordt ontwikkeld op het gebied van methaanvorming (CH4) in de riolering en mogelijkheden om de emissie van methaan op een zuivering te reduceren. Met betrekking tot lachgas N2O wordt onderzoek gedaan naar de vormingsprocessen van lachgas en de wijze waarop deze vrijkomt vanuit een rwzi. Verder worden relaties tussen lachgasemissie en procesparameters inzichtelijk gemaakt. Met deze kennis is het hopelijk in de toekomst mogelijk om maatregelen te nemen die de vorming en emissie van lachgas vanuit rwzi's te reduceren.

Ion mobilities in Xe/Ne and other rare-gas mixtures

Energy Technology Data Exchange (ETDEWEB)

Piscitelli, D; Pitchford, L C [Centre de Physique des Plasmas et Applications de Toulouse (CPAT), UMR 5002 CNRS, 118 route de Narbonne, 31062 Toulouse (France); Phelps, A V [JILA, University of Colorado and National Institute of Technology, Boulder, Colorado (United States); Urquijo, J de [Centro de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Post Office Box 48-3, 62251, 80309-0440 Cuernavaca, Moreno (Mexico); Basurto, E [Departmento de Ciencias Basicas, Universidad Autonoma Metropolitana, 02200 Mexico Distrito Federal (Mexico)

2003-10-01

The ion mobility or drift velocity data important for modeling glow discharges in rare gas mixtures are not generally available, nor are the ion-neutral scattering cross sections needed to calculate these data. In this paper we propose a set of cross sections for Xe{sup +} and Ne{sup +} collisions with Xe and Ne atoms. Ion mobilities at 300 K calculated using this cross section set in a Monte Carlo simulation are reported for reduced field strengths, E/N, up to 1500x10{sup -21} V m{sup 2}, in pure gases and in Xe/Ne mixtures containing 5% and 20% Xe/Ne, which are mixtures of interest for plasma display panels (PDPs). The calculated Xe{sup +} mobilities depend strongly on the mixture composition, but the Ne{sup +} mobility varies only slightly with increasing Xe in the mixture over the range studied here. The mobilities in pure gases compare well with available experimental values, and mobilities in gas mixtures at low E/N compare well with our recent measurements which will be published separately. Results from these calculations of ion mobilities are used to evaluate the predictions of Blanc's law and of the mixture rule proposed by Mason and Hahn [Phys. Rev. A 5, 438 (1972)] for determining the ion mobilities in mixtures from a knowledge of the mobilities in each of the pure gases. The mixture rule of Mason and Hahn is accurate to better than 10% at high field strengths over a wide range of conditions of interest for modeling PDPs. We conclude that a good estimate of ion mobilities at high E/N in Xe/Ne and other binary rare gas mixtures can be obtained using this mixture rule combined with known values of mobilities in parent gases and with the Langevin form for mobility of rare gas ions ion in other gases. This conclusion is supported by results in Ar/Ne mixtures which are also presented here.

Radiation-induced transformations of isolated organic molecules in solid rare gas matrices

International Nuclear Information System (INIS)

Feldman, V.I.

1998-01-01

Complete text of publication follows. The studies of radiation-chemical behaviour of isolated organic molecules in rigid inert media are of considerable interest for radiation chemistry and general structural chemistry. Previous efforts were limited to the ESR studies of radicals resulting from some small hydrocarbon molecules in frozen rare gas solutions. Recently, we developed an approach to the radiation chemistry of isolated organic molecules using classic matrix isolation procedure for sample preparation and a combination of ESR and IR spectroscopy for characterization of paramagnetic and diamagnetic species resulting form electron irradiation or organic molecules in solid rare gas matrices at 10-15 K. The results obtained reveal high efficiency of energy transfer from rare gas matrix to organic molecules. The total radiation-chemical yields of degradation of organic molecules in argon and xenon matrices were measured directly by IR spectroscopy. The studies of the effect of electron scavengers on the radiolysis of organic molecules in solid rare gases show that the main primary process is positive hole transfer from matrix to additive molecule. ESR spectra of a number of radical cations (alkanes, ethers, arenes) were first characterized in a low-disturbing environment. It was found that the electronic characteristics (IP, polarizability) of the matrix used had crucial effect on trapping and degradation of primary organic radical cations. Using matrices with various IP provides an unique possibility to examine the chemical meaning of excess energy resulting from exothermic positive hole transfer, that is, to follow the fate of excited cations in condensed phase

Charging of nanoparticles in stationary plasma in a gas aggregation cluster source

Science.gov (United States)

Blažek, J.; Kousal, J.; Biederman, H.; Kylián, O.; Hanuš, J.; Slavínská, D.

2015-10-01

Clusters that grow into nanoparticles near the magnetron target of the gas aggregation cluster source (GAS) may acquire electric charge by collecting electrons and ions or through other mechanisms like secondary- or photo-electron emissions. The region of the GAS close to magnetron may be considered as stationary plasma. The steady state charge distribution on nanoparticles can be determined by means of three possible models—fluid model, kinetic model and model employing Monte Carlo simulations—of cluster charging. In the paper the mathematical and numerical aspects of these models are analyzed in detail and close links between them are clarified. Among others it is shown that Monte Carlo simulation may be considered as a particular numerical technique of solving kinetic equations. Similarly the equations of the fluid model result, after some approximation, from averaged kinetic equations. A new algorithm solving an in principle unlimited set of kinetic equations is suggested. Its efficiency is verified on physical models based on experimental input data.

Ellis-van Creveld Syndrome

Directory of Open Access Journals (Sweden)

K Rajendra

2010-01-01

Full Text Available Ellis-van Creveld syndrome also known as chondroectodermal dysplasia is a rare genetic disorder of the skeletal dysplasia type, first described by Richard WS Ellis and Simon van Creveld in 1940. The syndrome manifests with several skeletal anomalies, oral mucosal and dental anomalies, congenital cardiac defects, nail dysplasia and polydactyly of one or both limbs. It is caused by mutation of EVC1 and EVC2 genes located in a head-to-head configuration on chromosome 4p16, which has been identified as the causative. The EVC phenotype is variable and affects multiple organs. The presence of oral mucosal and dental alterations, like the presence of numerous frenulum, oligodontia, bellshaped anterior teeth, hypoplastic erupted teeth with high-caries index, will confirm the diagnosis of Ellis-van Creveld syndrome and hence its importance to dentists.

Using the van der Waals broadening of spectral atomic lines to measure the gas temperature of an argon-helium microwave plasma at atmospheric pressure

International Nuclear Information System (INIS)

Munoz, J.; Dimitrijevic, M.S.; Yubero, C.; Calzada, M.D.

2009-01-01

The applications of plasmas generated with gas mixtures have become increasingly common in different scientific and technological fields. In order to understand the advantages of these discharges, for instance in chemical analysis, it is necessary to know the gas temperature (T g , kinetic energy of the heavy particles) since it has a great influence on the atomization reactions of the molecules located in the discharge, along with the dependence of the reaction rate on this parameter. The ro-vibrational emission spectra of the molecular species are usually used to measure the gas temperature of a discharge at atmospheric pressure although under some experimental conditions, these are difficult to detect. In such cases, the gas temperature can be determined from the van der Waals broadening of the emitted atomic spectral lines related to this parameter. The method proposed is based on the van der Waals broadening taking into account two perturbers

CONSTRAINING CLUSTER PHYSICS WITH THE SHAPE OF X-RAY CLUSTERS: COMPARISON OF LOCAL X-RAY CLUSTERS VERSUS ΛCDM CLUSTERS

International Nuclear Information System (INIS)

Lau, Erwin T.; Nagai, Daisuke; Kravtsov, Andrey V.; Vikhlinin, Alexey; Zentner, Andrew R.

2012-01-01

Recent simulations of cluster formation have demonstrated that condensation of baryons into central galaxies during cluster formation can drive the shape of the gas distribution in galaxy clusters significantly rounder out to their virial radius. These simulations generally predict stellar fractions within cluster virial radii that are ∼2-3 times larger than the stellar masses deduced from observations. In this paper, we compare ellipticity profiles of simulated clusters performed with varying input physics (radiative cooling, star formation, and supernova feedback) to the cluster ellipticity profiles derived from Chandra and ROSAT observations, in an effort to constrain the fraction of gas that cools and condenses into the central galaxies within clusters. We find that local relaxed clusters have an average ellipticity of ε = 0.18 ± 0.05 in the radial range of 0.04 ≤ r/r 500 ≤ 1. At larger radii r > 0.1r 500 , the observed ellipticity profiles agree well with the predictions of non-radiative simulations. In contrast, the ellipticity profiles of simulated clusters that include dissipative gas physics deviate significantly from the observed ellipticity profiles at all radii. The dissipative simulations overpredict (underpredict) ellipticity in the inner (outer) regions of galaxy clusters. By comparing simulations with and without dissipative gas physics, we show that gas cooling causes the gas distribution to be more oblate in the central regions, but makes the outer gas distribution more spherical. We find that late-time gas cooling and star formation are responsible for the significantly oblate gas distributions in cluster cores, but the gas shapes outside of cluster cores are set primarily by baryon dissipation at high redshift (z ≥ 2). Our results indicate that the shapes of X-ray emitting gas in galaxy clusters, especially at large radii, can be used to place constraints on cluster gas physics, making it potential probes of the history of baryonic

Self-Assembled Gold Nano-Ripple Formation by Gas Cluster Ion Beam Bombardment.

Science.gov (United States)

Tilakaratne, Buddhi P; Chen, Quark Y; Chu, Wei-Kan

2017-09-08

In this study, we used a 30 keV argon cluster ion beam bombardment to investigate the dynamic processes during nano-ripple formation on gold surfaces. Atomic force microscope analysis shows that the gold surface has maximum roughness at an incident angle of 60° from the surface normal; moreover, at this angle, and for an applied fluence of 3 × 10 16 clusters/cm², the aspect ratio of the nano-ripple pattern is in the range of ~50%. Rutherford backscattering spectrometry analysis reveals a formation of a surface gradient due to prolonged gas cluster ion bombardment, although the surface roughness remains consistent throughout the bombarded surface area. As a result, significant mass redistribution is triggered by gas cluster ion beam bombardment at room temperature. Where mass redistribution is responsible for nano-ripple formation, the surface erosion process refines the formed nano-ripple structures.

Impacts of the abolition of NOx emission trade; Effecten van de afschaffing van NOx- emissiehandel

Energy Technology Data Exchange (ETDEWEB)

Kroon, P [ECN Beleidsstudies, Petten (Netherlands)

2012-09-15

The consequences of abolishing the NOx emission trade have been analyzed for the installations that are covered by BEMS legislation (Dutch decree on emission limits for medium-sized combustion plants). The following aspects have been analyzed: What are the enforcement costs if these installations need to comply with BEMS requirements as of 2014?; How are these costs distributed across the various sectors and in particular for the sectors of onshore/offshore gas and oil extraction, greenhouse horticulture and hospitals?; To what extent can costs be lowered by allowing a 2-,3- or 5-year delay of the implementation date for existing installations in BEMS? To answer the above questions, data were used from the NEA (Netherlands Emission Authority) at sector level. Model calculations were conducted to determine the costs and effects [Dutch] De gevolgen van de afschaffing van NOx-emissiehandel zijn geanalyseerd voor het installatiepark dat terugvalt op BEMS-wetgeving (Besluit emissie-eisen middelgrote stookinstallaties). De volgende zaken zijn geanalyseerd: Wat zijn de nalevingskosten indien vanaf 2014 deze installaties aan de BEMS-eisen moeten voldoen?; Hoe zijn deze kosten verdeeld over de verschillende sectoren en in het bijzonder voor de sectoren offshore/onshore gas- en oliewinning, de glastuinbouw en ziekenhuizen?; In hoeverre zijn de kosten te verlagen door 2, 3 of 5 jaar uitstel te geven ten opzichte van de implementatiedatum voor bestaande installaties in BEMS? Voor het beantwoorden van de bovenstaande vragen is gebruik gemaakt van gegevens van de NEa (Nederlandse Emissie autoriteit) op sectorniveau. Met modelberekeningen zijn hiermee kosten en effecten bepaald.

Onderzoek naar het verband tussen instrumenteel bepaald breukgedrag en sensorisch bepaalde textuur van pizza's

NARCIS (Netherlands)

Oortwijn, H.; Herstel, H.

1988-01-01

Het breukgedrag van 34 pizzabodemmonsters is instrumenteel bepaald. Met behulp van de cluster- respectievelijk principale - componenten analyse is de verzameling pizza's in groepen verdeeld, die zich in breukgedrag onderscheidden. Nagegaan is in hoeverre deze groepsindeling overeenstemde met die van

Fragmentation of cluster ions produced by electron impact ionization

International Nuclear Information System (INIS)

Parajuli, R.

2001-12-01

By studying fragmentation of dimer and cluster ions produced by electron impact ionization of a neutral cluster beam, it is possible to elucidate structure, stability and energetics of these species and the dynamics of the corresponding decay reactions. Fragmentation of carbon cluster ions formed from C 6 0 fullerenes, rare gas cluster ions and dimer ions and simple molecular cluster ions (oxygen and nitrogen) and dimer ions have been studied in this thesis using a high resolution two sector field mass spectrometer of reversed geometry and a NIER type electron impact ion source. Spontaneous decay reactions of triply and quadruply charged C 4 0 z + and C 4 1 z + cluster ions which are formed from C 6 0 fullerenes by electron impact ionization have been analyzed. A new but very weak decay reaction for the even-sized carbon clusters ions is observed, namely loss of C 3 . The odd-sized clusters ions preferentially decay by loss of carbon atoms and, to a lesser degree, trimers. A weak signal due to C 2 loss is observed for C 4 1 3 + ion. These decay channels are discussed in terms of the geometric structure of these metastable, relatively cold cluster ions. Measurements on metastable fragmentation of mass selected rare gas cluster ions (Ne, Ar, Kr) which are produced by electron impact ionization of a neutral rare gas cluster beam have been carried out. From the shape of the fragment ion peaks (MIKE scan technique) information about the distribution of kinetic energy that is released in the decay reaction can be deduced. In this study, the peak shape observed for cluster ions with sizes larger than five is Gaussian and thus from the peak width the mean kinetic energy release of the corresponding decay reactions can be calculated. Using finite heat bath theory, the binding energies of the decaying cluster ions are calculated from these data and have been compared to data in the literature where available. In addition to the decay reactions of cluster ions the metastable

A scan statistic to extract causal gene clusters from case-control genome-wide rare CNV data

Directory of Open Access Journals (Sweden)

Scherer Stephen W

2011-05-01

Full Text Available Abstract Background Several statistical tests have been developed for analyzing genome-wide association data by incorporating gene pathway information in terms of gene sets. Using these methods, hundreds of gene sets are typically tested, and the tested gene sets often overlap. This overlapping greatly increases the probability of generating false positives, and the results obtained are difficult to interpret, particularly when many gene sets show statistical significance. Results We propose a flexible statistical framework to circumvent these problems. Inspired by spatial scan statistics for detecting clustering of disease occurrence in the field of epidemiology, we developed a scan statistic to extract disease-associated gene clusters from a whole gene pathway. Extracting one or a few significant gene clusters from a global pathway limits the overall false positive probability, which results in increased statistical power, and facilitates the interpretation of test results. In the present study, we applied our method to genome-wide association data for rare copy-number variations, which have been strongly implicated in common diseases. Application of our method to a simulated dataset demonstrated the high accuracy of this method in detecting disease-associated gene clusters in a whole gene pathway. Conclusions The scan statistic approach proposed here shows a high level of accuracy in detecting gene clusters in a whole gene pathway. This study has provided a sound statistical framework for analyzing genome-wide rare CNV data by incorporating topological information on the gene pathway.

Cooking a `Sausage': the impact of merger shocks in cluster gas and galaxy evolution

Science.gov (United States)

Stroe, Andra; Sobral, David; Harwood, Jeremy; Van Weeren, Reinout J.; Rumsey, Clare; Intema, Huib; Röttgering, Huub; Brüggen, Marcus; Saunders, Richard; Hardcastle, Martin; Hoeft, Matthias

2015-01-01

Galaxy clusters mainly grow through mergers with other clusters and groups. Major mergers give rise to important astrophysical phenomena such as the segregation of dark and luminous matter and the formation of cluster-wide traveling shocks and also drive galaxy evolution. The observable effects of shock waves can be seen at radio wavelengths as relics: elongated, diffuse synchrotron emitting areas located at the periphery of merging clusters. Despite the great interest in relics, candidates with simple geometry, undisturbed morphology and high surface brightness are scarce. The `Sausage' cluster hosts an extraordinary Mpc-wide relic, which enables us to study to study particle acceleration and the effects of shocks on cluster galaxies. We use a unique combination of facilities (INT, WHT, Keck, Subaru, CFHT, GMRT, WSRT, AMI) to obtain the first cluster-wide, multi-wavelength, multi-method analysis aimed at giving a complete picture of a merging cluster with relics. Using the radio data, we derive shock properties and the magnetic field structure for the relic. Using spectral modeling, we test acceleration and electron energy-loss mechanisms and resolve the discrepancy between the Mach number calculated from the radio and X-rays. Our results indicate that particles are shock-accelerated, but turbulent re-acceleration or unusually efficient transport of particles in the downstream area and line-of-sight mixing are important effects. We demonstrate the feasibility of high-frequency observations of radio relics, by presenting a 16 GHz detection of the `Sausage' relic. The radio analysis is complemented by Hα mapping of the cluster volume, aimed at providing the first direct test as to whether the shock drives or prohibits star formation. We find numerous Hα emitting galaxies in close proximity to the radio relic which are extremely massive, metal-rich, mostly star-forming with evidence for gas mass loss though outflows. We speculate that the complex interaction

Van Allen Probes, THEMIS, GOES, and Cluster observations of EMIC waves, ULF pulsations, and an electron flux dropout

Czech Academy of Sciences Publication Activity Database

Sigsbee, K.; Kletzing, C. A.; Smith, C. W.; MacDowall, R.; Spence, H.; Reeves, G.; Blake, J. B.; Baker, D. N.; Green, J. C.; Singer, H. J.; Carr, C.; Santolík, Ondřej

2016-01-01

Roč. 121, č. 3 (2016), s. 1990-2008 ISSN 2169-9380 Grant - others:AV ČR(CZ) AP1401 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:68378289 Keywords : EMIC waves * ULF pulsations * electron flux dropouts * Dst effect * magnetopause shadowing * Van Allen Probes Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.733, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/2014JA020877/full

Emergence of vanA Enterococcus faecium in Denmark, 2005-15

DEFF Research Database (Denmark)

Hammerum, Anette M; Baig, Sharmin; Kamel, Yasmin

2017-01-01

Objectives: To describe the changing epidemiology of vancomycin-resistant Enterococcus faecium and Enterococcus faecalis in clinical samples in Denmark 2005-15 according to species and van type, and, furthermore, to investigate the genetic relatedness of the clinical E. faecium isolates from 2015...... were detected along with 1 vanA E. faecalis and 1 vanB E. faecalis . cgMLST subdivided the 368 vanA E. faecium isolates into 33 cluster types (CTs), whereas the vanB E. faecium isolate belonged to a different CT. ST203-CT859 was most prevalent (51%), followed by ST80-CT14 (22%), ST117-CT24 (6%), ST80...

Hydrostatic models of gas in clusters in an unsteady state in the irregular field

International Nuclear Information System (INIS)

Sidorov, K.A.

1985-01-01

A study is made of the hydrostatic distribution of gas in a system in a steady state in the regular field but an unsteady one in the irregular field. Such a system has a velocity distribution with mean square of the radial velocity greater than the mean square of the transversal. Clusters of galaxies probably have such a structure. It is found that the connection between the densities of the gas and the galaxies established by Cavaliere and Fusco-Femiano also holds for isothermal gas in the considered system. Hydrostatic equilibrium of the gas does not hold for clusters with very large asymmetry of the velocity distribution function of the galaxies. The surface brightness of the x-ray emission of the gas is calculated

Condensation and dissociation rates for gas phase metal clusters from molecular dynamics trajectory calculations

Science.gov (United States)

Yang, Huan; Goudeli, Eirini; Hogan, Christopher J.

2018-04-01

In gas phase synthesis systems, clusters form and grow via condensation, in which a monomer binds to an existing cluster. While a hard-sphere equation is frequently used to predict the condensation rate coefficient, this equation neglects the influences of potential interactions and cluster internal energy on the condensation process. Here, we present a collision rate theory-molecular dynamics simulation approach to calculate condensation probabilities and condensation rate coefficients. We use this approach to examine atomic condensation onto 6-56-atom Au and Mg clusters. The probability of condensation depends upon the initial relative velocity (v) between atom and cluster and the initial impact parameter (b). In all cases, there is a well-defined region of b-v space where condensation is highly probable, and outside of which the condensation probability drops to zero. For Au clusters with more than 10 atoms, we find that at gas temperatures in the 300-1200 K range, the condensation rate coefficient exceeds the hard-sphere rate coefficient by a factor of 1.5-2.0. Conversely, for Au clusters with 10 or fewer atoms and for 14- and 28-atom Mg clusters, as cluster equilibration temperature increases, the condensation rate coefficient drops to values below the hard-sphere rate coefficient. Calculations also yield the self-dissociation rate coefficient, which is found to vary considerably with gas temperature. Finally, calculations results reveal that grazing (high b) atom-cluster collisions at elevated velocity (>1000 m s-1) can result in the colliding atom rebounding (bounce) from the cluster surface or binding while another atom dissociates (replacement). The presented method can be applied in developing rate equations to predict material formation and growth rates in vapor phase systems.

Detection of hot gas in clusters of galaxies by observation of the microwave background radiation

International Nuclear Information System (INIS)

Gull, S.F.; Northover, K.J.E.

1976-01-01

It is stated that satellite observations have indicated that many rich clusters are powerful sources of x-rays. This has been interpreted as due to either thermal bremsstrahlung from very hot gas filling the clusters or as inverse Compton scattering of photons by relativistic electrons. Spectral evidence appears to favour a thermal origin for the radiation, implying the existence of large amounts of hot gas. This gas may be a major constituent of the Universe, and independent confirmation of its existence is very important. Observations are here reported of small diminutions in the cosmic microwave background radiation in the direction of several rich clusters of galaxies. This is considered to confirm the existence of large amounts of very hot gas in these clusters and to indicate that the x-radiation is thermal bremsstrahlung and not inverse Compton emission. The observations were made in 1975/1976 using the 25m. telescope at the SRC Appleton Laboratory at a frequency of 10.6 GH2, and details are given of the technique employed. (U.K.)

Correlation between centre offsets and gas velocity dispersion of galaxy clusters in cosmological simulations

Science.gov (United States)

Li, Ming-Hua; Zhu, Weishan; Zhao, Dong

2018-05-01

The gas is the dominant component of baryonic matter in most galaxy groups and clusters. The spatial offsets of gas centre from the halo centre could be an indicator of the dynamical state of cluster. Knowledge of such offsets is important for estimate the uncertainties when using clusters as cosmological probes. In this paper, we study the centre offsets roff between the gas and that of all the matter within halo systems in ΛCDM cosmological hydrodynamic simulations. We focus on two kinds of centre offsets: one is the three-dimensional PB offsets between the gravitational potential minimum of the entire halo and the barycentre of the ICM, and the other is the two-dimensional PX offsets between the potential minimum of the halo and the iterative centroid of the projected synthetic X-ray emission of the halo. Haloes at higher redshifts tend to have larger values of rescaled offsets roff/r200 and larger gas velocity dispersion σ v^gas/σ _{200}. For both types of offsets, we find that the correlation between the rescaled centre offsets roff/r200 and the rescaled 3D gas velocity dispersion, σ _v^gas/σ _{200} can be approximately described by a quadratic function as r_{off}/r_{200} ∝ (σ v^gas/σ _{200} - k_2)2. A Bayesian analysis with MCMC method is employed to estimate the model parameters. Dependence of the correlation relation on redshifts and the gas mass fraction are also investigated.

Signs of Transition; Tekens van Transitie

Energy Technology Data Exchange (ETDEWEB)

Van Leenders, C.; Baidenmann, J.

2010-05-15

This book contains 14 inspiring experiences with making the energy system more sustainable that make clear that the energy transition is progressing. Two examples are provided for each of the seven themes: (1) Sustainable electricity (Agriport A7, Wind park Prinses Amalia); (2) Energy in the built environment (passive houses, conceptual building); (3) Chain efficiency (searching for CO2, process intensification); (4) New gas (biogas from manure, High efficiency boiler); (5) Sustainable mobility (electric driving, bus on biogas); (6) greenhouse as source of energy (closing the greenhouses, tomatoes on geothermal heat); and (7) green resources (biorefinery of grass, pyrolisis of biomass) [Dutch] Dit boek bevat veertien inspirerende ervaringen met verduurzaming van de energiehuishouding die duidelijk maken dat er voortgang zit in energietransitie. Er worden twee voorbeelden gegeven voor elk van de zeven thema's: (1) Duurzame Elektriciteit (Agriport A7, Windpark Prinses Amalia); (2) Energie in de Gebouwde Omgeving (Passiefhuizen, Conceptueel Bouwen); (3) Keten-Efficiency (Op zoek naar CO2, Procesintensificatie); (4) Nieuw Gas (Biogas uit mest, HR-e ketel); (5) Duurzame Mobiliteit (Elektrisch rijden, Bus op biogas); (6) Kas als Energiebron (De kassen sluiten, Tomaten op aardwarmte); en (7) Groene Grondstoffen (Bioraffinage van gras, Pyrolyse van biomassa)

Eerste inschatting van vrijkomen van plastics als gevolg van slijtage van Mosselzaad-Invagsystemen (MZI's)

NARCIS (Netherlands)

Hartog, E.; Brink, van den A.M.; Kamermans, P.

2014-01-01

IMARES heeft onderzoek uitgevoerd naar het ontstaan en de aanwezigheid van microplastic zwerfvuil afkomstig van mosselzaad invangsystemen (hierna MZI’s genoemd). Deze studie is onderdeel van een opdracht van het ministerie van EL&I, om de ecologische effecten van opschaling van MZI’s in de

Ellis-van Creveld syndrome: its history.

Science.gov (United States)

Muensterer, Oliver J; Berdon, Walter; McManus, Chris; Oestreich, Alan; Lachman, Ralph S; Cohen, M Michael; Done, Stephen

2013-08-01

The story of Ellis-van Creveld syndrome is one of serendipity. By chance, Simon van Creveld and Richard Ellis purportedly met on a train and combined their independently encountered patients with short stature, dental anomalies and polydactyly into one landmark publication in 1940. They included a patient used in work published previously by Rustin McIntosh without naming McIntosh as a coauthor. This patient was followed radiologically by Caffey for nearly two decades. In 1964, Victor McKusick felt compelled to investigate a brief report in an obscure pharmaceutical journal on an unusual geographic cluster of short-statured Amish patients in Pennsylvania. This review highlights the lives of the individuals involved in the discovery of Ellis-van Creveld syndrome in their historic context.

Genetics Home Reference: Ellis-van Creveld syndrome

Science.gov (United States)

... bone growth that results in very short stature (dwarfism). People with this condition have particularly short forearms ... Ellis-van Creveld Syndrome Encyclopedia: Polydactyly Health Topic: Dwarfism Genetic and Rare Diseases Information Center (1 link) ...

Metal nitride cluster as a template to tune the electronic and magnetic properties of rare-earth metal containing endohedral fullerenes

International Nuclear Information System (INIS)

Zhang, Yang

2013-01-01

Rare-earth metal containing endohedral fullerenes have attracted much attention due to the feasibility of encaging metal atom, atoms or cluster inside of carbon cages. By switching the metal atom or cluster entrapped inside of the carbon cage the physical and chemical properties of the fullerene compounds can be tuned. The understanding of magnetic and electrochemical properties of endohedral fullerenes plays an essential role in fundamental scientific researches and potential applications in materials science. In this thesis, synthesizing novel rare-earth metal containing endohedral fullerene structures, studying the properties of these isolated endohedral fullerenes and the strategies of tuning the electronic and magnetic properties of endohedral fullerenes were introduced. The DC-arc discharging synthesis of different lanthanide metal-based (Ho, Ce and Pr) mixed metal nitride clusterfullerenes was achieved. Those rare-earth metal containing endohedral fullerenes were isolated by multi-step HPLC. The isolated samples were characterized by spectroscopic techniques included UV-vis-NIR, FTIR, Raman, LDI-TOF mass spectrometry, NMR and electrochemistry. The Ho-based mixed metal nitride clusterfullerenes Ho x M 3-x N rate at C 80 (M= Sc, Lu, Y; x=1, 2) were synthesized by ''reactive gas atmosphere'' method or ''selective organic solid'' route. The isolated samples were characterized by LDI-TOF mass spectrometry, UV-vis-NIR, FTIR, Raman and NMR spectroscopy. The 13 C NMR spectroscopic studies demonstrated exceptional NMR behaviors that resulted from switching the second metal inside of the mixed metal nitride cluster Ho x M 3-x N from Sc to Lu and further to Y. The LnSc 2 N rate at C 80 (Ln= Ce, Pr, Nd, Tb, Dy, Ho, Lu) MMNCFs were characterized by 13 C and 45 Sc NMR study respectively. According to Bleaney's theory and Reilley method, the separation of δ PC and δ con from δ para was achieved by the primary 13 C and 45 Sc NMR analysis of LnSc 2 N rate at C 80 (I). The

Formation of new stellar populations from gas accreted by massive young star clusters.

Science.gov (United States)

Li, Chengyuan; de Grijs, Richard; Deng, Licai; Geller, Aaron M; Xin, Yu; Hu, Yi; Faucher-Giguère, Claude-André

2016-01-28

Stars in clusters are thought to form in a single burst from a common progenitor cloud of molecular gas. However, massive, old 'globular' clusters--those with ages greater than ten billion years and masses several hundred thousand times that of the Sun--often harbour multiple stellar populations, indicating that more than one star-forming event occurred during their lifetimes. Colliding stellar winds from late-stage, asymptotic-giant-branch stars are often suggested to be triggers of second-generation star formation. For this to occur, the initial cluster masses need to be greater than a few million solar masses. Here we report observations of three massive relatively young star clusters (1-2 billion years old) in the Magellanic Clouds that show clear evidence of burst-like star formation that occurred a few hundred million years after their initial formation era. We show that such clusters could have accreted sufficient gas to form new stars if they had orbited in their host galaxies' gaseous disks throughout the period between their initial formation and the more recent bursts of star formation. This process may eventually give rise to the ubiquitous multiple stellar populations in globular clusters.

Electron impact fragmentation of size-selected krypton clusters

Czech Academy of Sciences Publication Activity Database

Steinbach, Ch.; Fárník, Michal; Buck, U.; Brindle, C. A.; Janda, K. C.

2006-01-01

Roč. 110, č. 29 (2006), s. 9108-9115 ISSN 1089-5639 Grant - others:Deutsche Forschungsgemeinschaft(DE) GRK 782; US National Science Foundation(US) CHE-0213149 Institutional research plan: CEZ:AV0Z40400503 Keywords : rare-gas cluster * bombardment fragmentation * scattering analysis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.047, year: 2006

Dynamics and Fragmentation of Hydrogen Bonded and van der Waal Clusters upon 26.5 eV Soft X-ray Laser Ionization

Science.gov (United States)

Dong, Feng; Heinbuch, Scott; Bernstein, Elliot; Rocca, Jorge

2006-05-01

A desk-top soft x-ray laser is applied to the study of water, methanol, ammonia, sulfur dioxide, carbon dioxide, mixed sulfur dioxide-water, and mixed carbon dioxide-water clusters through single photon ionization time of flight mass spectroscopy. Almost all of the energy above the vertical ionization energy is removed by the ejected electron. Protonated water, methanol, and ammonia clusters dominate the mass spectra for the first three systems. The temperatures of the neutral water and methanol clusters can be estimated. In the case of pure SO2 and CO2, the mass spectra are dominated by (SO2)n^+ and (CO2)n^+ cluster series. When a high or low concentration of SO2/CO2 is mixed with water, we observe (SO2/CO2)nH2O^+ or SO2/CO2(H2O)nH^+ in the mass spectra, respectively. The unimolecular dissociation rate constants for reactions involving loss of one neutral molecule are calculated for the protonated water, methanol, and ammonia clusters as well as for SO2 and CO2 clusters. We find that the 26.5 eV soft x-ray laser is a nearly ideal tool for the study of hydrogen bonded and van der Waals cluster systems and we are currently exploring its usefulness for other more strongly bound systems.

Cause and Effect of Feedback: Multiphase Gas in Cluster Cores Heated by AGN Jets

Science.gov (United States)

Gaspari, M.; Ruszkowski, M.; Sharma, P.

2012-02-01

Multiwavelength data indicate that the X-ray-emitting plasma in the cores of galaxy clusters is not cooling catastrophically. To a large extent, cooling is offset by heating due to active galactic nuclei (AGNs) via jets. The cool-core clusters, with cooler/denser plasmas, show multiphase gas and signs of some cooling in their cores. These observations suggest that the cool core is locally thermally unstable while maintaining global thermal equilibrium. Using high-resolution, three-dimensional simulations we study the formation of multiphase gas in cluster cores heated by collimated bipolar AGN jets. Our key conclusion is that spatially extended multiphase filaments form only when the instantaneous ratio of the thermal instability and free-fall timescales (t TI/t ff) falls below a critical threshold of ≈10. When this happens, dense cold gas decouples from the hot intracluster medium (ICM) phase and generates inhomogeneous and spatially extended Hα filaments. These cold gas clumps and filaments "rain" down onto the central regions of the core, forming a cold rotating torus and in part feeding the supermassive black hole. Consequently, the self-regulated feedback enhances AGN heating and the core returns to a higher entropy level with t TI/t ff > 10. Eventually, the core reaches quasi-stable global thermal equilibrium, and cold filaments condense out of the hot ICM whenever t TI/t ff fashion. The effective spatial redistribution of heat is enabled in part by the turbulent motions in the wake of freely falling cold filaments. Increased AGN activity can locally reverse the cold gas flow, launching cold filamentary gas away from the cluster center. Our criterion for the condensation of spatially extended cold gas is in agreement with observations and previous idealized simulations.

CAUSE AND EFFECT OF FEEDBACK: MULTIPHASE GAS IN CLUSTER CORES HEATED BY AGN JETS

International Nuclear Information System (INIS)

Gaspari, M.; Ruszkowski, M.; Sharma, P.

2012-01-01

Multiwavelength data indicate that the X-ray-emitting plasma in the cores of galaxy clusters is not cooling catastrophically. To a large extent, cooling is offset by heating due to active galactic nuclei (AGNs) via jets. The cool-core clusters, with cooler/denser plasmas, show multiphase gas and signs of some cooling in their cores. These observations suggest that the cool core is locally thermally unstable while maintaining global thermal equilibrium. Using high-resolution, three-dimensional simulations we study the formation of multiphase gas in cluster cores heated by collimated bipolar AGN jets. Our key conclusion is that spatially extended multiphase filaments form only when the instantaneous ratio of the thermal instability and free-fall timescales (t TI /t ff ) falls below a critical threshold of ≈10. When this happens, dense cold gas decouples from the hot intracluster medium (ICM) phase and generates inhomogeneous and spatially extended Hα filaments. These cold gas clumps and filaments 'rain' down onto the central regions of the core, forming a cold rotating torus and in part feeding the supermassive black hole. Consequently, the self-regulated feedback enhances AGN heating and the core returns to a higher entropy level with t TI /t ff > 10. Eventually, the core reaches quasi-stable global thermal equilibrium, and cold filaments condense out of the hot ICM whenever t TI /t ff ∼< 10. This occurs despite the fact that the energy from AGN jets is supplied to the core in a highly anisotropic fashion. The effective spatial redistribution of heat is enabled in part by the turbulent motions in the wake of freely falling cold filaments. Increased AGN activity can locally reverse the cold gas flow, launching cold filamentary gas away from the cluster center. Our criterion for the condensation of spatially extended cold gas is in agreement with observations and previous idealized simulations.

Gas capture and rare gas retention by accreting planets in the solar nebula

International Nuclear Information System (INIS)

Mizuno, H.; Nakazawa, K.; Hayashi, C.

1982-01-01

In this paper, the physico-chemical effects of the nebula gas on the planets are reviewed from a standpoint of planetary formation in the solar nebula. The proto-Earth growing in the nebula was surrounded by a primordial atmosphere with a solar chemical composition and solar isotopic composition. When the mass of the proto-Earth was greater than 0.3 times the present Earth mass, the surface was molten because of the blanketing effect of the atmosphere. Therefore, the primordial rare gases contained in the primordial atmosphere dissolved into the molten Earth material without fractionation and in particular the dissolved neon is expected to be conserved in the present Earth material. Hence, if dissolved neon with a solar isotopic ratio is discovered in the Earth material, it will indicate that the Earth was formed in the nebula and that the dissolved rare gases were one of the sources which degassed to form the present atmosphere. (author)

Protogalaxy interactions in newly formed clusters: Galaxy luminosities, colors, and intergalactic gas

International Nuclear Information System (INIS)

Silk, J.

1978-01-01

The role of protogalaxy interactions in galactic evolution is studied during the formation of galaxy clusters. In the early stages of the collapse, coalescent encounters of protogalaxies lead to the development of a galactic luminosity function. Once galaxies acquire appreciable random motions, mutual collisions between galaxies in rich clusters will trigger the collapse of interstellar clouds to form stars. This provides both a source for enriched intracluster gas and an interpretation of the correlation between luminosity and color for cluster elliptical galaxies. Other observational consequences that are considered include optical, X-ray, and diffuse nonthermal radio emission from newly formed clusters of galaxies

A study on rare gas - oxygen reactions excited by low temperature plasma

Energy Technology Data Exchange (ETDEWEB)

Ogawa, Hiroaki; Kiuchi, Kiyoshi; Saburi, Tei; Fukaya, Kiyoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2001-03-01

The concentration of radioactive rare gases like Xe and Kr in nuclear fuels on PWRs and BWRs increases promptly with dependent on the burn-up ratio. These gases are affect to the long performance of nuclear fuel elements due to accumulate in gap between cladding and fuel, because it has the low thermal conductivity. It is also required to develop the practical means to correct these gases including in the off-gas in nuclear plants for inhibiting the environmental pollution. On the present study, we carried out the fundamental research to evaluate the chemical reactivity of these gases under heavy irradiation. We proposed the new excitation mechanism of these gases by expecting the formation of low energy plasma under irradiation. The chemical reactivity on rare gas-oxygen system was examined by using the low energy plasma driven reaction apparatus installed the RF excitation source. The density of electrons and lower pressure limit for the RF excitation was depended on the ionization energy of each gas. It is clarified that Xe is easy to form gaseous oxide due to the high excitation efficiency in low energy plasma. (author)

Gas. Innovators talking; Gas. Innovators aan het woord

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-02-15

Qualitative studies have been conducted of the results of completed projects focused on energy innovation, spread over the seven themes of the top sector Energy: Energy saving in industry, Energy conservation in the built environment, Gas, Bio-energy, Smart grids, Offshore Wind, Solar PV. This provides insight into the follow-up activities and lessons of some EOS (Energy Research Subsidy) completed projects with the aim to inspire, connect and strengthen the TKIs (Topconsortia for Knowledge and Innovation) and individual companies and researchers working on energy innovation. This report concerns the research on gas [Dutch] Er is een kwalitatief onderzoek uitgevoerd naar de resultaten van afgeronde projecten gericht op energie-innovatie, verdeeld over de zeven thema's van de topsector Energie: Energiebesparing in de industrie; Energiebesparing in de gebouwde omgeving; Gas; Bio-energie; Smart grids; Wind op zee; Zon-pv. Daarmee wordt inzicht gegeven in de vervolgactiviteiten en lessen van een aantal afgesloten EOS-projecten (Energie Onderzoek Subsidie) met het oog op het inspireren, verbinden en versterken van de TKI's (Topconsortia voor Kennis en Innovatie) en individuele bedrijven en onderzoekers die werken aan energie-innovatie. Dit rapport betreft het onderzoek naar gas.

Gas. Innovators talking; Gas. Innovators aan het woord

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-02-15

Qualitative studies have been conducted of the results of completed projects focused on energy innovation, spread over the seven themes of the top sector Energy: Energy saving in industry, Energy conservation in the built environment, Gas, Bio-energy, Smart grids, Offshore Wind, Solar PV. This provides insight into the follow-up activities and lessons of some EOS (Energy Research Subsidy) completed projects with the aim to inspire, connect and strengthen the TKIs (Topconsortia for Knowledge and Innovation) and individual companies and researchers working on energy innovation. This report concerns the research on gas [Dutch] Er is een kwalitatief onderzoek uitgevoerd naar de resultaten van afgeronde projecten gericht op energie-innovatie, verdeeld over de zeven thema's van de topsector Energie: Energiebesparing in de industrie; Energiebesparing in de gebouwde omgeving; Gas; Bio-energie; Smart grids; Wind op zee; Zon-pv. Daarmee wordt inzicht gegeven in de vervolgactiviteiten en lessen van een aantal afgesloten EOS-projecten (Energie Onderzoek Subsidie) met het oog op het inspireren, verbinden en versterken van de TKI's (Topconsortia voor Kennis en Innovatie) en individuele bedrijven en onderzoekers die werken aan energie-innovatie. Dit rapport betreft het onderzoek naar gas.

RESIDUAL GAS MOTIONS IN THE INTRACLUSTER MEDIUM AND BIAS IN HYDROSTATIC MEASUREMENTS OF MASS PROFILES OF CLUSTERS

International Nuclear Information System (INIS)

Lau, Erwin T.; Kravtsov, Andrey V.; Nagai, Daisuke

2009-01-01

We present analysis of bulk and random gas motions in the intracluster medium using high-resolution Eulerian cosmological simulations of 16 simulated clusters, including both very relaxed and unrelaxed systems and spanning a virial mass range of 5 x 10 13 - 2 x 10 15 h -1 M-odot. We investigate effects of the residual subsonic gas motions on the hydrostatic estimates of mass profiles and concentrations of galaxy clusters. In agreement with previous studies, we find that the gas motions contribute up to ∼5%-15% of the total pressure support in relaxed clusters with contribution increasing with the cluster-centric radius. The fractional pressure support is higher in unrelaxed systems. This contribution would not be accounted for in hydrostatic estimates of the total mass profile and would lead to systematic underestimate of mass. We demonstrate that total mass can be recovered accurately if pressure due to gas motions measured in simulations is explicitly taken into account in the equation of hydrostatic equilibrium. Given that the underestimate of mass is increasing at larger radii, where gas is less relaxed and contribution of gas motions to pressure is larger, the total density profile derived from hydrostatic analysis is more concentrated than the true profile. This may at least partially explain some high values of concentrations of clusters estimated from hydrostatic analysis of X-ray data.

Diffusion Monte Carlo simulations of gas phase and adsorbed D2-(H2)n clusters

Science.gov (United States)

Curotto, E.; Mella, M.

2018-03-01

We have computed ground state energies and analyzed radial distributions for several gas phase and adsorbed D2(H2)n and HD(H2)n clusters. An external model potential designed to mimic ionic adsorption sites inside porous materials is used [M. Mella and E. Curotto, J. Phys. Chem. A 121, 5005 (2017)]. The isotopic substitution lowers the ground state energies by the expected amount based on the mass differences when these are compared with the energies of the pure clusters in the gas phase. A similar impact is found for adsorbed aggregates. The dissociation energy of D2 from the adsorbed clusters is always much higher than that of H2 from both pure and doped aggregates. Radial distributions of D2 and H2 are compared for both the gas phase and adsorbed species. For the gas phase clusters, two types of hydrogen-hydrogen interactions are considered: one based on the assumption that rotations and translations are adiabatically decoupled and the other based on nonisotropic four-dimensional potential. In the gas phase clusters of sufficiently large size, we find the heavier isotopomer more likely to be near the center of mass. However, there is a considerable overlap among the radial distributions of the two species. For the adsorbed clusters, we invariably find the heavy isotope located closer to the attractive interaction source than H2, and at the periphery of the aggregate, H2 molecules being substantially excluded from the interaction with the source. This finding rationalizes the dissociation energy results. For D2-(H2)n clusters with n ≥12 , such preference leads to the desorption of D2 from the aggregate, a phenomenon driven by the minimization of the total energy that can be obtained by reducing the confinement of (H2)12. The same happens for (H2)13, indicating that such an effect may be quite general and impact on the absorption of quantum species inside porous materials.

A Significant Enhancement of Cluster Formation of Krypton and Xenon Gases

Institute of Scientific and Technical Information of China (English)

LIU Bingchen

2001-01-01

@@ Clusters of rare gases have currently become a kind of widely used targets in the study of high-intensity laser interaction with matter［1,2］. However, a good understanding of the cluster media is vital if results from laser-cluster interaction experiments are to be interpreted correctly. During the course of investigation of the time history of a cluster jet generated in supersonic expansion of rare gases into vaccum through a supersonic conical nozzle (26 mm long, opening angle 5°) by time resolving Rayleigh scattering measurements in which a 532 nm 0.3 mJ laser beam was used, we find that the general trend of argon clusters is similar to that reported by R.A. Smith et al.［3］. However, the picture for Krypton and Xenon gases is completely different. A two-peak structure of the scattered light intensity, instead of a single-peak one, has been revealed. It is interesting to note that the second peak is much more stronger than the first one. As an example, Fig.1 shows the time history of Xen clusters produced at a gas backing pressure P0=3 atm. In the Figure, the peak intensity of the second peak is surprisingly 62 times higher than the first one, indicating that the average cluster size c in the latter case is increased about 62 times under the assumption that during the expansion process all the atoms in the gas condensate into clusters. The result, which is believed to be related to a double gas ejection via the pulsed valve′s two adjacent openings, is of significant importance since this effect would be promising for applications in which very large size clusters are required while a relatively modest vacuum maintains. Meanwhile, this finding may provide us with the opportunity of a further understanding into the nucleation mechanism of expanding gases in a nozzle.

Modified Van der Waals equation and law of corresponding states

Science.gov (United States)

Zhong, Wei; Xiao, Changming; Zhu, Yongkai

2017-04-01

It is well known that the Van der Waals equation is a modification of the ideal gas law, yet it can be used to describe both gas and liquid, and some important messages can be obtained from this state equation. However, the Van der Waals equation is not a precise state equation, and it does not give a good description of the law of corresponding states. In this paper, we expand the Van der Waals equation into its Taylor's series form, and then modify the fourth order expansion by changing the constant Virial coefficients into their analogous ones. Via this way, a more precise result about the law of corresponding states has been obtained, and the law of corresponding states can then be expressed as: in terms of the reduced variables, all fluids should obey the same equation with the analogous Virial coefficients. In addition, the system of 3 He with quantum effects has also been taken into consideration with our modified Van der Waals equation, and it is found that, for a normal system without quantum effect, the modification on ideal gas law from the Van der Waals equation is more significant than the real case, however, for a system with quantum effect, this modification is less significant than the real case, thus a factor is introduced in this paper to weaken or strengthen the modification of the Van der Waals equation, respectively.

A combined heating cooling stage for cluster thermalization in the gas phase

International Nuclear Information System (INIS)

Ievlev, D.N.; Kuester, A.; Enders, A.; Malinowski, N.; Schaber, H.; Kern, K.

2003-01-01

We report on the design and performance of a combined heating/cooling stage for the thermalization of clusters in a gas phase time-of-flight mass spectrometer. With this setup the cluster temperature can sensitively be adjusted within the range from 100 up to 800 K and higher. The unique combination of a heating stage with a subsequent cooling stage allows us to perform thermodynamic investigations on clusters at very high temperatures without quality losses in the spectra due to delayed fragmentation in the drift tube of the mass spectrometer. The performance of the setup is demonstrated by the example of (C 60 ) n clusters

Gas cluster ion beam assisted NiPt germano-silicide formation on SiGe

Energy Technology Data Exchange (ETDEWEB)

Ozcan, Ahmet S., E-mail: asozcan@us.ibm.com [IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120 (United States); Lavoie, Christian; Jordan-Sweet, Jean [IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598 (United States); Alptekin, Emre; Zhu, Frank [IBM Semiconductor Research and Development Center, 2070 Route 52, Hopewell Junction, New York 12533 (United States); Leith, Allen; Pfeifer, Brian D.; LaRose, J. D.; Russell, N. M. [TEL Epion Inc., 900 Middlesex Turnpike, Bldg. 6, Billerica, Massachusetts 01821 (United States)

2016-04-21

We report the formation of very uniform and smooth Ni(Pt)Si on epitaxially grown SiGe using Si gas cluster ion beam treatment after metal-rich silicide formation. The gas cluster ion implantation process was optimized to infuse Si into the metal-rich silicide layer and lowered the NiSi nucleation temperature significantly according to in situ X-ray diffraction measurements. This novel method which leads to more uniform films can also be used to control silicide depth in ultra-shallow junctions, especially for high Ge containing devices, where silicidation is problematic as it leads to much rougher interfaces.

Gas density fluctuations in the Perseus Cluster: clumping factor and velocity power spectrum

Energy Technology Data Exchange (ETDEWEB)

Zhuravleva, I.; Churazov, E.; Arevalo, P.; Schekochihin, A. A.; Allen, S. W.; Fabian, A. C.; Forman, W. R.; Sanders, J. S.; Simionescu, A.; Sunyaev, R.; Vikhlinin, A.; Werner, N.

2015-05-20

X-ray surface brightness fluctuations in the core of the Perseus Cluster are analysed, using deep observations with the Chandra observatory. The amplitude of gas density fluctuations on different scales is measured in a set of radial annuli. It varies from 7 to 12 per cent on scales of ~10–30 kpc within radii of 30–220 kpc from the cluster centre. Using a statistical linear relation between the observed amplitude of density fluctuations and predicted velocity, the characteristic velocity of gas motions on each scale is calculated. The typical amplitudes of the velocity outside the central 30 kpc region are 90–140 km s^-1 on ~20–30 kpc scales and 70–100 km s^-1 on smaller scales ~7–10 kpc. The velocity power spectrum (PS) is consistent with cascade of turbulence and its slope is in a broad agreement with the slope for canonical Kolmogorov turbulence. The gas clumping factor estimated from the PS of the density fluctuations is lower than 7–8 per cent for radii ~30–220 kpc from the centre, leading to a density bias of less than 3–4 per cent in the cluster core. Uncertainties of the analysis are examined and discussed. Future measurements of the gas velocities with the Astro-H, Athena and Smart-X observatories will directly measure the gas density–velocity perturbation relation and further reduce systematic uncertainties in this analysis.

Energy efficiency and use of natural gas show a changed view of energy consumption in the USA in 2011; Energie efficientie en gasgebruik leidden tot een veranderd beeld van energieverbuik in de VS in 2011

Energy Technology Data Exchange (ETDEWEB)

Louzada, K.

2012-11-15

The Lawrence Livermore National Laboratory (LLNL) recently published estimates of energy consumption in the USA. The total energy consumption in the USA decreased by almost 2% since 2008. This decrease is attributed to increasing energy efficiency in households and transport. The increase in renewable energy shows how the current policy has promoted the growth of these technologies. In addition, the use of natural gas increased significantly as a result of shale gas extraction and reduced use of coal [Dutch] Het Lawrence Livermore National Laboratory (LLNL) publiceerde recentelijk schattingen van het energieverbruik in de VS. Het totale energieverbruik in de VS is met bijna 2% gedaald sinds 2008. Deze daling wordt toegeschreven aan toenemende energie-efficientie in huishoudens en transport. De toename van duurzame energie geeft weer hoe het huidige beleid de groei van deze technologieen heeft bevorderd. Daarnaast is door de opkomst van schaliegas winning het gebruik van aardgas aanzienlijk toegenomen en het gebruik van steenkool afgenomen.

Non-additive non-interacting kinetic energy of rare gas dimers

Science.gov (United States)

Jiang, Kaili; Nafziger, Jonathan; Wasserman, Adam

2018-03-01

Approximations of the non-additive non-interacting kinetic energy (NAKE) as an explicit functional of the density are the basis of several electronic structure methods that provide improved computational efficiency over standard Kohn-Sham calculations. However, within most fragment-based formalisms, there is no unique exact NAKE, making it difficult to develop general, robust approximations for it. When adjustments are made to the embedding formalisms to guarantee uniqueness, approximate functionals may be more meaningfully compared to the exact unique NAKE. We use numerically accurate inversions to study the exact NAKE of several rare-gas dimers within partition density functional theory, a method that provides the uniqueness for the exact NAKE. We find that the NAKE decreases nearly exponentially with atomic separation for the rare-gas dimers. We compute the logarithmic derivative of the NAKE with respect to the bond length for our numerically accurate inversions as well as for several approximate NAKE functionals. We show that standard approximate NAKE functionals do not reproduce the correct behavior for this logarithmic derivative and propose two new NAKE functionals that do. The first of these is based on a re-parametrization of a conjoint Perdew-Burke-Ernzerhof (PBE) functional. The second is a simple, physically motivated non-decomposable NAKE functional that matches the asymptotic decay constant without fitting.

The Raman and vibronic activity of intermolecular vibrations in aromatic-containing complexes and clusters

International Nuclear Information System (INIS)

Maxton, P.M.; Schaeffer, M.W.; Ohline, S.M.; Kim, W.; Venturo, V.A.; Felker, P.M.

1994-01-01

Theoretical and experimental results pertaining to the excitation of intermolecular vibrations in the Raman and vibronic spectra of aromatic-containing, weakly bound complexes and clusters are reported. The theoretical analysis of intermolecular Raman activity is based on the assumption that the polarizability tensor of a weakly bound species is given by the sum of the polarizability tensors of its constituent monomers. The analysis shows that the van der Waals bending fundamentals in aromatic--rare gas complexes may be expected to be strongly Raman active. More generally, it predicts strong Raman activity for intermolecular vibrations that involve the libration or internal rotation of monomer moieties having appreciable permanent polarizability anisotropies. The vibronic activity of intermolecular vibrations in aromatic-rare gas complexes is analyzed under the assumption that every vibronic band gains its strength from an aromatic-localized transition. It is found that intermolecular vibrational excitations can accompany aromatic-localized vibronic excitations by the usual Franck--Condon mechanism or by a mechanism dependent on the librational amplitude of the aromatic moiety during the course of the pertinent intermolecular vibration. The latter mechanism can impart appreciable intensity to bands that are forbidden by rigid-molecule symmetry selection rules. The applicability of such rules is therefore called into question. Finally, experimental spectra of intermolecular transitions, obtained by mass-selective, ionization-detected stimulated Raman spectroscopies, are reported for benzene--X (X=Ar, --Ar 2 , N 2 , HCl, CO 2 , and --fluorene), fluorobenzene--Ar and --Kr, aniline--Ar, and fluorene--Ar and --Ar 2 . The results support the conclusions of the theoretical analyses and provide further evidence for the value of Raman methods in characterizing intermolecular vibrational level structures

Studies of cluster-assembled materials: From gas phase to condensed phase

Science.gov (United States)

Gao, Lin

Clusters, defined as "a number of similar things that occur together" in Webster's dictionary, has different meanings depending on the given subject. To physicists and chemists, the word cluster means "a group of atoms or molecules formed by interactions ranging from very weak van der Waals interactions to strong ionic bonds." Unlike molecules, which are made by nature and are stable under ambient conditions, clusters discovered in a laboratory are often metastable. Molecules have specific stoichiometry, whereas the cluster's composition can usually be altered atom by atom. Thus, clusters can be taken as intrinsically "artificial molecules" with considerably more tunabilities in their properties. Research into the relative stability and instability of clusters has in recent years become a very active research area, especially following the study by Khanna and Castleman that first suggested that by varying size and composition, clusters can expand the periodic table to the 3 rd-dimension; that is, clusters can mimic the chemistry of atoms and may, therefore, be used as the building blocks of new materials. The discovery of Met-Cars has drawn worldwide interests and has been actively investigated by researchers from a variety of fields, including physics, chemistry and material science. However, the unsuccessful search for a solvent capable of isolating Met-Cars has impeded progress in characterizing the material in the condensed state and, hence, limited its potential applications as a novel nanoscale material. An alternative method involving the deposition of mass-gated species and the subsequent structural investigation via Transmission Electron Microscopy (TEM) has been employed. With particularly interesting results, soft-landed deposits of zirconium Met-Cars were found to form a face-centered-cubic (FCC) structure with a lattice parameter ˜ 15A. The production of Met-Cars is conducted with the direct laser vaporization (DLV) of metal/graphite composite pellets

Ring Current Response to Different Storm Drivers. Van Allen Probes and Cluster Observations.

Science.gov (United States)

Bingham, S.; Mouikis, C.; Kistler, L. M.; Spence, H. E.; Gkioulidou, M.; Claudepierre, S. G.; Farrugia, C. J.

2015-12-01

The ring current responds differently to the different solar and interplanetary storm drivers such as coronal mass injections, (CME's), co-rotating interaction regions (CIR's), high-speed streamers and other structures. The resulting changes in the ring current particle pressure change the global magnetic field, which affects the transport of the radiation belts. In order to determine the field changes during a storm it is necessary to understand the transport, sources and losses of the particles that contribute to the ring current. The source population of the storm time ring current is the night side plasma sheet. However, it is not clear how these convecting particles affect the storm time ring current pressure development. We use Van Allen Probes and Cluster observations together with the Volland-Stern and dipole magnetic field models to determine the contribution in the ring current pressure of the plasma sheet particles convecting from the night side that are on open drift paths, during the storm evolution. We compare storms that are related to different interplanetary drivers, CME and CIR, as observed at different local times.

Guinier-Preston zones and gas bubbles clustering studied by dechanneling

International Nuclear Information System (INIS)

Desarmot, Georges.

1976-11-01

Dechanneling due to precipitation of heteroatoms in aluminium is studied theoretically and experimentally. Precipitation of copper atoms leads to Guinier-Preston zones (G.P.Z.) clustering. Helium, which is insoluble in aluminium, forms gas bubbles. An isotropic source of particles is used and channeling events only are considered. Transmission of channeled particles (channelons) through a sample is defined as the ratio between the channelon flux emerging from a sample containing defects (G.P.Z. or gaz bubbles in this survey) and the channelon flux emerging from the same sample without defects. Dechanneling by G.P.Z. clustering during isothermal ageing of Al-Cu alloys at room temperature is studied. The results are interpreted exclusively in terms of spinodal decomposition of the Al-Cu solid solution. A simple theory of dechanneling by bubbles containing a real gas is proposed. Applied to helium in aluminium, this theory explains the experimental results. Dechanneling proves to be a new and efficient technique for studying alloys [fr

Diagnosing Cervical Neoplasia in Rural Brazil Using a Mobile Van Equipped with In Vivo Microscopy: A Cluster-Randomized Community Trial.

Science.gov (United States)

Hunt, Brady; Fregnani, José Humberto Tavares Guerreiro; Schwarz, Richard A; Pantano, Naitielle; Tesoni, Suelen; Possati-Resende, Júlio César; Antoniazzi, Marcio; de Oliveira Fonseca, Bruno; de Macêdo Matsushita, Graziela; Scapulatempo-Neto, Cristovam; Kerr, Ligia; Castle, Philip E; Schmeler, Kathleen; Richards-Kortum, Rebecca

2018-06-01

Cervical cancer is a leading cause of death in underserved areas of Brazil. This prospective randomized trial involved 200 women in southern/central Brazil with abnormal Papanicolaou tests. Participants were randomized by geographic cluster and referred for diagnostic evaluation either at a mobile van upon its scheduled visit to their local community, or at a central hospital. Participants in both arms underwent colposcopy, in vivo microscopy, and cervical biopsies. We compared rates of diagnostic follow-up completion between study arms, and also evaluated the diagnostic performance of in vivo microscopy compared with colposcopy. There was a 23% absolute and 37% relative increase in diagnostic follow-up completion rates for patients referred to the mobile van (102/117, 87%) compared with the central hospital (53/83, 64%; P = 0.0001; risk ratio = 1.37, 95% CI, 1.14-1.63). In 229 cervical sites in 144 patients, colposcopic examination identified sites diagnosed as cervical intraepithelial neoplasia grade 2 or more severe (CIN2+; 85 sites) with a sensitivity of 94% (95% CI, 87%-98%) and specificity of 50% (95% CI, 42%-58%). In vivo microscopy with real-time automated image analysis identified CIN2+ with a sensitivity of 92% (95% CI, 84%-97%) and specificity of 48% (95% CI, 40%-56%). Women referred to the mobile van were more likely to complete their diagnostic follow-up compared with those referred to a central hospital, without compromise in clinical care. In vivo microscopy in a mobile van provides automated diagnostic imaging with sensitivity and specificity similar to colposcopy. Cancer Prev Res; 11(6); 359-70. ©2018 AACR . ©2018 American Association for Cancer Research.

The development of a cryopump for stripper gas pumping in a 30 MV tandem Van de Graaff

International Nuclear Information System (INIS)

Halliday, B.S.

1980-04-01

The development of a cryopump is described for a 30 MV tandem Van de Graaf accelerator to control the vacuum pressure in the beam tube at the centre terminal when a gas stripper is in use. The system has been fully assembled and has been mechanically tested, the cryo pumps have been cooled to 18 0 K and the insulation tested electrically to +- 20 kV between the pump elements and the biased stripper canal. (UK)

The effect of gas dynamics on semi-analytic modelling of cluster galaxies

Science.gov (United States)

Saro, A.; De Lucia, G.; Dolag, K.; Borgani, S.

2008-12-01

We study the degree to which non-radiative gas dynamics affect the merger histories of haloes along with subsequent predictions from a semi-analytic model (SAM) of galaxy formation. To this aim, we use a sample of dark matter only and non-radiative smooth particle hydrodynamics (SPH) simulations of four massive clusters. The presence of gas-dynamical processes (e.g. ram pressure from the hot intra-cluster atmosphere) makes haloes more fragile in the runs which include gas. This results in a 25 per cent decrease in the total number of subhaloes at z = 0. The impact on the galaxy population predicted by SAMs is complicated by the presence of `orphan' galaxies, i.e. galaxies whose parent substructures are reduced below the resolution limit of the simulation. In the model employed in our study, these galaxies survive (unaffected by the tidal stripping process) for a residual merging time that is computed using a variation of the Chandrasekhar formula. Due to ram-pressure stripping, haloes in gas simulations tend to be less massive than their counterparts in the dark matter simulations. The resulting merging times for satellite galaxies are then longer in these simulations. On the other hand, the presence of gas influences the orbits of haloes making them on average more circular and therefore reducing the estimated merging times with respect to the dark matter only simulation. This effect is particularly significant for the most massive satellites and is (at least in part) responsible for the fact that brightest cluster galaxies in runs with gas have stellar masses which are about 25 per cent larger than those obtained from dark matter only simulations. Our results show that gas dynamics has only a marginal impact on the statistical properties of the galaxy population, but that its impact on the orbits and merging times of haloes strongly influences the assembly of the most massive galaxies.

Metal nitride cluster as a template to tune the electronic and magnetic properties of rare-earth metal containing endohedral fullerenes

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yang

2013-10-16

Rare-earth metal containing endohedral fullerenes have attracted much attention due to the feasibility of encaging metal atom, atoms or cluster inside of carbon cages. By switching the metal atom or cluster entrapped inside of the carbon cage the physical and chemical properties of the fullerene compounds can be tuned. The understanding of magnetic and electrochemical properties of endohedral fullerenes plays an essential role in fundamental scientific researches and potential applications in materials science. In this thesis, synthesizing novel rare-earth metal containing endohedral fullerene structures, studying the properties of these isolated endohedral fullerenes and the strategies of tuning the electronic and magnetic properties of endohedral fullerenes were introduced. The DC-arc discharging synthesis of different lanthanide metal-based (Ho, Ce and Pr) mixed metal nitride clusterfullerenes was achieved. Those rare-earth metal containing endohedral fullerenes were isolated by multi-step HPLC. The isolated samples were characterized by spectroscopic techniques included UV-vis-NIR, FTIR, Raman, LDI-TOF mass spectrometry, NMR and electrochemistry. The Ho-based mixed metal nitride clusterfullerenes Ho{sub x}M{sub 3-x}N rate at C{sub 80} (M= Sc, Lu, Y; x=1, 2) were synthesized by ''reactive gas atmosphere'' method or ''selective organic solid'' route. The isolated samples were characterized by LDI-TOF mass spectrometry, UV-vis-NIR, FTIR, Raman and NMR spectroscopy. The {sup 13}C NMR spectroscopic studies demonstrated exceptional NMR behaviors that resulted from switching the second metal inside of the mixed metal nitride cluster Ho{sub x}M{sub 3-x}N from Sc to Lu and further to Y. The LnSc{sub 2}N rate at C{sub 80} (Ln= Ce, Pr, Nd, Tb, Dy, Ho, Lu) MMNCFs were characterized by {sup 13}C and {sup 45}Sc NMR study respectively. According to Bleaney's theory and Reilley method, the separation of δ{sup PC} and δ{sup con

Momentum distributions of selected rare-gas atoms probed by intense femtosecond laser pulses

DEFF Research Database (Denmark)

Abu-Samha, Mahmoud; Madsen, Lars Bojer

2011-01-01

We provide a direct comparison between numerical and experimental (Rudenko et al 2004 J. Phys. B: At. Mol. Opt. Phys. 37 L407) photoelectron momentum distributions in strong-field ionization of selected rare-gas atoms (He, Ne and Ar), probed by femtosecond linearly polarized laser pulses. The cal......We provide a direct comparison between numerical and experimental (Rudenko et al 2004 J. Phys. B: At. Mol. Opt. Phys. 37 L407) photoelectron momentum distributions in strong-field ionization of selected rare-gas atoms (He, Ne and Ar), probed by femtosecond linearly polarized laser pulses....... The calculations are performed by solving the time-dependent Schrödinger equation within the single-active-electron approximation, and focal-volume effects are taken into account by appropriately averaging the results. The resulting momentum distributions are in quantitative agreement with the experimental...

Globular Clusters for Faint Galaxies

Science.gov (United States)

Kohler, Susanna

2017-07-01

The origin of ultra-diffuse galaxies (UDGs) has posed a long-standing mystery for astronomers. New observations of several of these faint giants with the Hubble Space Telescope are now lending support to one theory.Faint-Galaxy MysteryHubble images of Dragonfly 44 (top) and DFX1 (bottom). The right panels show the data with greater contrast and extended objects masked. [van Dokkum et al. 2017]UDGs large, extremely faint spheroidal objects were first discovered in the Virgo galaxy cluster roughly three decades ago. Modern telescope capabilities have resulted in many more discoveries of similar faint galaxies in recent years, suggesting that they are a much more common phenomenon than we originally thought.Despite the many observations, UDGs still pose a number of unanswered questions. Chief among them: what are UDGs? Why are these objects the size of normal galaxies, yet so dim? There are two primary models that explain UDGs:UDGs were originally small galaxies, hence their low luminosity. Tidal interactions then puffed them up to the large size we observe today.UDGs are effectively failed galaxies. They formed the same way as normal galaxies of their large size, but something truncated their star formation early, preventing them from gaining the brightness that we would expect for galaxies of their size.Now a team of scientists led by Pieter van Dokkum (Yale University) has made some intriguing observations with Hubble that lend weight to one of these models.Globulars observed in 16 Coma-cluster UDGs by Hubble. The top right panel shows the galaxy identifications. The top left panel shows the derived number of globular clusters in each galaxy. [van Dokkum et al. 2017]Globulars GaloreVan Dokkum and collaborators imaged two UDGs with Hubble: Dragonfly 44 and DFX1, both located in the Coma galaxy cluster. These faint galaxies are both smooth and elongated, with no obvious irregular features, spiral arms, star-forming regions, or other indications of tidal interactions

vanO, a new glycopeptide resistance operon in environmental Rhodococcus equi isolates

DEFF Research Database (Denmark)

Gudeta, Dereje Dadi; Moodley, Arshnee; Bortolaia, Valeria

2014-01-01

We describe sequence and gene organization of a new glycopeptide resistance operon (vanO) in Rhodococcus equi from soil. The vanO operon has low homology to enterococccal van operons and harbors a vanHOX cluster transcribed in opposite direction to the vanS-vanR regulatory system and comprised be...... between three open reading frames with unknown function. This finding has clinical interest since glycopeptides are used to treat R. equi infections and resistance has been reported in clinical isolates....

Term value/band-gap energy correlations for solid rare gas excitons

International Nuclear Information System (INIS)

Anon.

1987-01-01

Term value/ionization energy correlation algorithms have proven to be of considerable utility in the assignment of atomic and molecular Rydberg states. Many examples of empirical term value/ionization energy correlations are known for diverse classes of atoms and molecules. The purpose of this paper is to demonstrate that similar correlations are also obtained for excitons in rare gas solids

Observed damage during Argon gas cluster depth profiles of compound semiconductors

Energy Technology Data Exchange (ETDEWEB)

Barlow, Anders J., E-mail: anders.barlow@ncl.ac.uk; Portoles, Jose F.; Cumpson, Peter J. [National EPSRC XPS Users' Service (NEXUS), School of Mechanical and Systems Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)

2014-08-07

Argon Gas Cluster Ion Beam (GCIB) sources have become very popular in XPS and SIMS in recent years, due to the minimal chemical damage they introduce in the depth-profiling of polymer and other organic materials. These GCIB sources are therefore particularly useful for depth-profiling polymer and organic materials, but also (though more slowly) the surfaces of inorganic materials such as semiconductors, due to the lower roughness expected in cluster ion sputtering compared to that introduced by monatomic ions. We have examined experimentally a set of five compound semiconductors, cadmium telluride (CdTe), gallium arsenide (GaAs), gallium phosphide (GaP), indium arsenide (InAs), and zinc selenide (ZnSe) and a high-κ dielectric material, hafnium oxide (HfO), in their response to argon cluster profiling. An experimentally determined HfO etch rate of 0.025 nm/min (3.95 × 10{sup −2} amu/atom in ion) for 6 keV Ar gas clusters is used in the depth scale conversion for the profiles of the semiconductor materials. The assumption has been that, since the damage introduced into polymer materials is low, even though sputter yields are high, then there is little likelihood of damaging inorganic materials at all with cluster ions. This seems true in most cases; however, in this work, we report for the first time that this damage can in fact be very significant in the case of InAs, causing the formation of metallic indium that is readily visible even to the naked eye.

The interaction of super-intense ultra-short laser pulse and micro-clusters with large atomic clusters

International Nuclear Information System (INIS)

Miao Jingwei; Yang Chaowen; An Zhu; Yuan Xuedong; Sun Weiguo; Luo Xiaobing; Wang Hu; Bai Lixing; Shi Miangong; Miao Lei; Zhen Zhijian; Gu Yuqin; Liu Hongjie; Zhu Zhouseng; Sun Liwei; Liao Xuehua

2007-01-01

The fusion mechanism of large deuterium clusters (100-1000 Atoms/per cluster) in super-intense ultra-short laser pulse field, Coulomb explosions of micro-cluster in solids, gases and Large-size clusters have been studied using the interaction of a high-intensity femtosecond laser pulses with large deuterium clusters, collision of high-quality beam of micro-cluster from 2.5 MV van de Graaff accelerator with solids, gases and large clusters. The experimental advance of the project is reported. (authors)

Gas phase collision dynamics by means of pulse-radiolysis methods

International Nuclear Information System (INIS)

Hatano, Yoshihiko

1989-01-01

After a brief survey of recent advances in gas-phase collision dynamics studies using pulse radiolysis methods, the following two topics in our research programs are presented with emphasis on the superior advantages of the pulse radiolysis methods over the various methods of gas-phase collision dynamics, such as beam methods, swarm methods and flow methods. One of the topics is electron attachment to van der Waals molecules. The attachment rates of thermal electrons to O 2 and other molecules in dense gases have been measured in wide ranges of both gas temperatures and pressures, from which experimental evidence has been obtained for electron attachment to van der Waals molecules. The results have been compared with theories and discussed in terms of the effect of van der Waals interaction on the electron attachment resonance. The obtained conclusions have been related with investigations of electron attachment, solvation and localization in the condensed phase. The other is Penning ionization and its related processes. The rate constants for the de-excitation of He(2 1 P), He(2 3 S), Ne( 3 P 0 ), Ne( 3 P 1 ), Ne( 3 P 2 ), Ar( 1 P 1 ), Ar( 3 P 1 ), by atoms and molecules have been measured in the temperature range from 100 to 300 K, thus obtaining the collisional energy dependence of the de-excitation cross sections. The results are compared in detail with theories classified according to the excited rare gas atoms in the metastable and resonance states. (author)

Supplementary study of possible risks and consequences of the exploration and exploitation of shale and coal gas in the Netherlands. Final report of the research questions A and B; Aanvullend onderzoek naar mogelijke risico's en gevolgen van de opsporing en winning van schalie- en steenkoolgas in Nederland. Eindrapport onderzoeksvragen A en B

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-08-15

The Dutch Ministry of Economic Affairs has given the consortium consisting of Witteveen and Bos, Arcadis and Fugro an assignment to investigate the possible risks and effects of exploration and exploitation of shale gas and coal bed methane in The Netherlands. The main questions of the research have been outlined in 55 research question that have been answered in the shape of technical notes. This summary contains the most important findings of this research. Attention is paid to Conventional versus unconventional gas, Footprint and nuisance, Methane emissions and climate footprint, Earthquakes and subsidence, Water usage, Fraccing fluid, Safety, Ground water, Relation with current legislation [Dutch] Het Ministerie van Economische Zaken heeft het consortium Witteveen+Bos, Arcadis en Fugro opdracht gegeven voor een onderzoek naar mogelijke risico's en gevolgen van opsporen en winnen van schaliegas (en steenkoolgas) in Nederland. De hoofdvragen van het onderzoek zijn uitgewerkt in 55 onderzoeksvragen, die in achtergrondnotities zijn beantwoord. Aandacht is besteed aan Conventioneel versus onconventioneel gas, Ruimtebeslag en hinder, Methaanemissies en klimaatvoetafdruk, Bodembewegingen, Watergebruik, Frac-vloeistof, Veiligheid, Grondwater, en de Relatie met huidige mijnbouwwetgeving.

Infrared photodissociation of van der Waals molecules containing ethylene

International Nuclear Information System (INIS)

Casassa, M.P.; Bomse, D.S.; Janda, K.C.

1981-01-01

Vibrational predissociation line shapes in the n 7 region of the ethylene spectrum are measured for van der Waals molecules of ethylene bound to Ne, Ar, Kr, C 2 H 4 , C 2 F 4 , and larger ethylene clusters. The predissociative rate is very fast for this group of molecules. The vibrationally excited state lifetimes are 0.44, 0.59 and 0.89 x 10 -12 sec for (C 2 H 4 ) 2 , ArxC 2 H 4 , and C 2 H 4 xC 2 F 4 respectively. That the observed line shapes are homogeneous is demonstrated by the fact that a low-power, narrow frequency bandwidth laser can dissociate a large fraction of the initial ensemble of ethylene clusters. The observed transition probability is proportional to the number of ethylene subunits for clusters containing three or fewer ethylene subunits. These observations are interpreted in terms of intramolecular energy flow directly from ethylene n 7 to the weak van der Waals modes of motion

Globular Clusters Shine in a Galaxy Lacking Dark Matter

Science.gov (United States)

Kohler, Susanna

2018-04-01

You may have seen recent news about NGC 1052DF2, a galaxy that was discovered to have little or no dark matter. Now, a new study explores what NGC 1052DF2 does have: an enigmatic population of unusually large and luminous globular clusters.Keck/LRIS spectra (left and right) and HST images (center) of the 11 clusters associated with NGC 1052DF2. The color images each span 1 1. [van Dokkum et al. 2018]An Unusual DwarfThe ultra-diffuse galaxy NGC 1052DF2, originally identified with the Dragonfly Telescope Array, has puzzled astronomers since the discovery that its dynamical mass determined by the motions of globular-cluster-like objects spotted within it is essentially the same as its stellar mass. This equivalence implies that the galaxy is strangely lacking dark matter; the upper limit set on its dark matter halo is 400 times smaller than what we would expect for such a dwarf galaxy.Led by Pieter van Dokkum (Yale University), the team that made this discovery has now followed up with detailed Hubble Space Telescope imaging and Keck spectroscopy. Their goal? To explore the objects that allowed them to make the dynamical-mass measurement: the oddly bright globular clusters of NGC 1052DF2.Sizes (circularized half-light radii) vs. absolute magnitudes for globular clusters in NGC1052DF2 (black) and the Milky Way (red). [Adapted from van Dokkum et al. 2018]Whats Up with the Globular Clusters?Van Dokkum and collaborators spectroscopically confirmed 11 compact objects associated with the faint galaxy. These objects are globular-cluster-like in their appearance, but the peak of their luminosity distribution is offset by a factor of four from globular clusters of other galaxies; these globular clusters are significantly brighter than is typical.Using the Hubble imaging, the authors determined that NGC 1052DF2s globular clusters are more than twice the size of the Milky Ways globular clusters in the same luminosity range. As is typical for globular clusters, they are an old

Properties of hot gas in halos of active galaxies and clusters of galaxies

International Nuclear Information System (INIS)

Durret-Isnard, F.

1982-05-01

The importance of the inverse Compton effect in the X-ray emission of cluster galaxies is discussed; the X-ray origin problem from galaxy clusters (spectra and emission mechanisms) is studied. The insufficiency of the X-ray bremsstrahlung emission model in an isothermal gas is proved. The ionized halos in narrow-line galaxies (NLG) are studied; after some general points on NLG, one NLG is described and a brief view an emission mechanism models is given; a detailed study of the galaxy IC 5063 and its nebulosity is given: the ionized gas density is calculated together with the evaporation rate for such clouds [fr

Possible ionization ''ignition'' in laser-driven clusters

International Nuclear Information System (INIS)

Rose-Petruck, C.; Schafer, K.J.; Barty, C.P.J.

1995-01-01

The authors use Classical Trajectory Monte Carlo (CTMC) simulations to study the ionization of small rare gas clusters in short pulse, high intensity laser fields. They calculate, for a cluster of 25 neon atoms, the ionization stage reached and the average kinetic energy of the ionized electrons as functions of time and peak laser intensity. The CTMC calculations mimic the results of the much simpler barrier suppression model in the limit of isolated atoms. At solid density the results give much more ionization in the cluster than that predicted by the barrier suppression model. They find that when the laser intensity reaches a threshold value such that on average one electron is ionized from each atom, the cluster atoms rapidly move to higher ionization stages, approaching Ne +8 in a few femtoseconds. This ignition process creates an ultrafast pulse of energetic electrons in the cluster at quite modest laser intensities

Smart with Natural Gas in the built environment; Slim met Gas in de gebouwde omgeving

Energy Technology Data Exchange (ETDEWEB)

Ensing, H.; Oude Elberink, L.; Holwerda, B. [et al.] (ed.)

2011-12-15

This magazine addresses the future of the energy system, the role of natural gas in the energy transition process and innovative (gas) technology for the built environment [Dutch] In dit magazine komen de toekomst van de energievoorziening, de rol van aardgas in het energietransitieproces en innovatieve (gas)technologie voor de gebouwde omgeving aan bod.

Spectroscopic and Kinetic Measurements of Alkali Atom-Rare Gas Excimers

Science.gov (United States)

2009-11-04

vapors – Exciplex molecules absorb over much greater bandwidth • Control of inherent high optical gain to minimize ASE and optimize laser oscillation... Exciplex assisted diode Pumped Alkali Laser (XPAL) • Education of a future generation of laser scientists VG09-227-2 Physical Sciences Inc. Novel Approach...This new laser exploits the optical properties of weakly-bound alkali/rare-gas exciplexes for pumping the 2P1/2, 3/2 alkali atomic excited states 4

Rare gas systematics: Formation of the atmosphere, evolution and structure of the Earth's mantle

International Nuclear Information System (INIS)

Allegre, C.J.; Staudacher, T.; Sarda, P.; Paris-6 Univ., 75; Paris-7 Univ., 75

1987-01-01

To explain the rare gas content and isotopic composition measured in modern terrestrial materials we explore in this paper an Earth model based on four reservoirs: atmosphere, continental crust, upper mantle and lower mantle. This exploration employs three tools: mass balance equations, the concept of mean age of outgassing and the systematic use of all of the rare gases involving both absolute amount and isotopic composition. The results obtained are as follows: half of the Earth's mantle is 99% outgassed. Outgassing occurred in an early very intense stage within the first 50 Ma of Earth history and a slow continuous stage which continues to the present day. The mean age of the atmosphere is 4.4 Ga. Our model with four main reservoirs explains quantitatively both isotopic and chemical ratios, assuming that He migrates from the lower to the upper mantle whereas the heavy rare gases did not. Noble gas fluxes for He, Ar and Xe from different reservoirs have been estimated. The results constrain the K content in the earth to 278 ppm. Several geodynamic consequences are discussed. (orig.)

X-ray Cavities in Galaxy Groups and Clusters: Central Gas Entropy ...

Indian Academy of Sciences (India)

is synchrotron radiation of relativistic electrons, powered by the central AGN, and ... In the X-ray images of galaxies, galaxy groups and clusters, a number of X-ray cavities have been observed. .... 35. Figure 1. Central gas entropy excess K0 vs.

Long-Range Memory in Literary Texts: On the Universal Clustering of the Rare Words.

Science.gov (United States)

Tanaka-Ishii, Kumiko; Bunde, Armin

2016-01-01

A fundamental problem in linguistics is how literary texts can be quantified mathematically. It is well known that the frequency of a (rare) word in a text is roughly inverse proportional to its rank (Zipf's law). Here we address the complementary question, if also the rhythm of the text, characterized by the arrangement of the rare words in the text, can be quantified mathematically in a similar basic way. To this end, we consider representative classic single-authored texts from England/Ireland, France, Germany, China, and Japan. In each text, we classify each word by its rank. We focus on the rare words with ranks above some threshold Q and study the lengths of the (return) intervals between them. We find that for all texts considered, the probability SQ(r) that the length of an interval exceeds r, follows a perfect Weibull-function, SQ(r) = exp(-b(β)rβ), with β around 0.7. The return intervals themselves are arranged in a long-range correlated self-similar fashion, where the autocorrelation function CQ(s) of the intervals follows a power law, CQ(s) ∼ s-γ, with an exponent γ between 0.14 and 0.48. We show that these features lead to a pronounced clustering of the rare words in the text.

Smoothing of ZnO films by gas cluster ion beam

International Nuclear Information System (INIS)

Chen, H.; Liu, S.W.; Wang, X.M.; Iliev, M.N.; Chen, C.L.; Yu, X.K.; Liu, J.R.; Ma, K.; Chu, W.K.

2005-01-01

Planarization of wide-band-gap semiconductor ZnO surface is crucial for thin-film device performance. In this study, the rough initial surfaces of ZnO films deposited by r.f. magnetron sputtering on Si substrates were smoothed by gas cluster ion beams. AFM measurements show that the average surface roughness (R a ) of the ZnO films could be reduced considerably from 16.1 nm to 0.9 nm. Raman spectroscopy was used to monitor the structure of both the as-grown and the smoothed ZnO films. Rutherford back-scattering in combination with channeling effect was used to study the damage production induced by the cluster bombardment

Versterking van de loopbaanladder van leraren : wat kunnen we leren van Singapore?

NARCIS (Netherlands)

Elffers, L.

2015-01-01

In de Lerarenagenda 2013-2020 is een aantal doelstellingen geformuleerd ten aanzien van de bevordering van de loopbaan en professionele ontwikkeling van leraren. Enerzijds wordt ingezet op het stimuleren van professionalisering van leraren na hun initiële opleiding, anderzijds op het versterken van

Collisional energy dependence of molecular ionization by metastable rare gas atoms

International Nuclear Information System (INIS)

Martin, R.M.; Parr, T.P.

1979-01-01

The collisional energy dependence of several molecular total ionization cross sections by metastable rare gas atoms was studied over the thermal energy region using the crossed molecular beam time-of-flight method. Results are reported for the collision systems He, Ne, and Ar ionizing the geometric isomers cis- and trans-dichloroethylene and ortho- and para-dichlorobenzene. The He ionization cross sections oscillate about an energy dependence of E/sup -1/2/ over the energy range 0.004--1.0 eV, and the Ar*+para-dichlorobenzene cross section oscillates about an energy dependence of E/sup -2/5/ over the energy range 0.011--0.64 eV. The remaining systems are characterized by ''bent'' E/sup -m/ dependences with m values of 0.56--0.70 at low energies changing to 0.07--0.29 at higher energies. Comparison with the slopes of the He* systems and the Ar*+para-dichlorobenzene system shows that the ''bent'' and ''oscillating'' energy dependences are similar except for the form of the cross section functions at the lowest energies. No systematic differences are found between the cross section energy dependences for ionization of different geometric isomers or for ionization by the different metastable rare gas atoms

Rare earth metals in North America; Zeldzame aardmetalen in Noord-Amerika

Energy Technology Data Exchange (ETDEWEB)

Louzada, K.

2012-11-15

The uncertain supply of rare earth metals (Rare Earth Elements) from China for the high tech industry in the U.S. is a barrier for innovation and the high-tech manufacturing industry. Many rare earths are applied in permanent magnets for sustainable energy generation and for energy storage systems in for example electric cars. Also other sectors feel the pressure of shortages. The federal government in the USA and US companies use the opportunity to encourage research into recycling, reducing the use and finding alternatives for rare earths. Canada sees in the uncertain supply and dwindling reserves in the USA and elsewhere an economic opportunity. Canada can start the development of hitherto unprofitable reserves of valuable materials. Both in the USA and Canada, the number of exploration projects in the mining industry has grown significantly [Dutch] De onzekere aanvoer van zeldzame aardmetalen (Rare Earth Elements) uit China voor de hightechindustrie vormt in de VS een hindernis voor innovatie en voor de hightech maakindustrie. Met name in permanente magneten voor duurzame energieopwekking en energieopslagsystemen voor bijvoorbeeld elektrische auto's worden veel zeldzame aardmetalen verwerkt. Ook andere sectoren staan onder druk. De federale overheid en bedrijven in de VS maken van de gelegenheid gebruik om onderzoek naar de recycling, vermindering van het gebruik en alternatieven voor zeldzame aardmetalen te stimuleren. Canada ziet de onzekere aanvoer en slinkende reserves in de VS en elders als een economische kans. Het land kan tot nu toe onrendabele voorkomens van de waardevolle materialen gaan ontwikkelen. Zowel in de VS als in Canada is het aantal exploratieprojecten in de mijnbouw aanzienlijk gegroeid.

Long-Range Memory in Literary Texts: On the Universal Clustering of the Rare Words.

Directory of Open Access Journals (Sweden)

Kumiko Tanaka-Ishii

Full Text Available A fundamental problem in linguistics is how literary texts can be quantified mathematically. It is well known that the frequency of a (rare word in a text is roughly inverse proportional to its rank (Zipf's law. Here we address the complementary question, if also the rhythm of the text, characterized by the arrangement of the rare words in the text, can be quantified mathematically in a similar basic way. To this end, we consider representative classic single-authored texts from England/Ireland, France, Germany, China, and Japan. In each text, we classify each word by its rank. We focus on the rare words with ranks above some threshold Q and study the lengths of the (return intervals between them. We find that for all texts considered, the probability SQ(r that the length of an interval exceeds r, follows a perfect Weibull-function, SQ(r = exp(-b(βrβ, with β around 0.7. The return intervals themselves are arranged in a long-range correlated self-similar fashion, where the autocorrelation function CQ(s of the intervals follows a power law, CQ(s ∼ s-γ, with an exponent γ between 0.14 and 0.48. We show that these features lead to a pronounced clustering of the rare words in the text.

Duurzame inzetbaarheid van ouderen: resultaten van de eerste twee metingen van STREAM

NARCIS (Netherlands)

Heuvel, S. van den; Ybema, J.F; Leijten, F.; Wind, A. de

2013-01-01

In deze notitie richten we ons op voorspellers van duurzame inzetbaarheid, waarbij we gebruik maken van de resultaten van de eerste twee metingen van STREAM en van een interviewstudie bij deelnemers aan STREAM. Meer specifiek gaan we na hoe personen met gezondheidsproblemen toch productief kunnen

Modelling of Krn+ Clusters (n = 2 - 20) I. Structures and Energetics

Czech Academy of Sciences Publication Activity Database

Kalus, R.; Paidarová, Ivana; Hrivňák, D.; Paška, P.; Gadea, F. X.

2003-01-01

Roč. 294, č. 2 (2003), s. 141-153 ISSN 0301-0104 R&D Projects: GA ČR GA203/00/1025; GA ČR GA203/01/1274 Institutional research plan: CEZ:AV0Z4040901 Keywords : cluster modelling * rare-gas ions * an initio potential Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.070, year: 2003

Device for separating and concentrating rare gases containing krypton gas

Energy Technology Data Exchange (ETDEWEB)

Kimura, S; Sugimoto, K

1975-06-11

In orer to highly concentrate krypton by means of adsorption and desorption of activated carbon, in a device for continuously separating and concentrating rare gases containing krypton gas by means of adsorbing and desorbing operation of activated carbon, the device includes adsorbers arranged in parallel and more than two stages of adsorbers arranged in series with the first mentioned adsorbers with the amount of activated carbon filled successively reduced, and a cooling mechanism for cooling the adsorbers when adsorbed and a heating mechanism for heating the adsorbers when desorbed.

Cluster-collision frequency. II. Estimation of the collision rate

International Nuclear Information System (INIS)

Amadon, A.S.; Marlow, W.H.

1991-01-01

Gas-phase cluster-collision rates, including effects of cluster morphology and long-range intermolecular forces, are calculated. Identical pairs of icosahedral or dodecahedral carbon tetrachloride clusters of 13, 33, and 55 molecules in two different relative orientations were discussed in the preceding paper [Phys. Rev. A 43, 5483 (1991)]: long-range interaction energies were derived based upon (i) exact calculations of the iterated, or many-body, induced-dipole interaction energies for the clusters in two fixed relative orientations; and (ii) bulk, or continuum descriptions (Lifshitz--van der Waals theory), of spheres of corresponding masses and diameters. In this paper, collision rates are calculated according to an exact description of the rates for small spheres interacting via realistic potentials. Utilizing the interaction energies of the preceding paper, several estimates of the collision rates are given by treating the discrete clusters in fixed relative orientations, by computing rotationally averaged potentials for the discrete clusters, and by approximating the clusters as continuum spheres. For the discrete, highly symmetric clusters treated here, the rates using the rotationally averaged potentials closely approximate the fixed-orientation rates and the values of the intercluster potentials for cluster surface separations under 2 A have negligible effect on the overall collision rates. While the 13-molecule cluster-collision rate differs by 50% from the rate calculated as if the cluster were bulk matter, the two larger cluster-collision rates differ by less than 15% from the macroscopic rates, thereby indicating the transition of microscopic to macroscopic behavior

Spatial distribution of ion energy related on electron density in a plasma channel generated in gas clusters by a femtosecond laser

International Nuclear Information System (INIS)

Nam, S. M.; Han, J. M.; Cha, Y. H.; Lee, Y. W.; Rhee, Y. J.; Cha, H. K.

2008-01-01

Neutron generation through Coulomb explosion of deuterium contained gas clusters is known as one of the very effective methods to produce fusion neutrons using a table top terawatt laser. The energy of ions produced through Coulomb explosions is very important factor to generate neutrons efficiently. Until the ion energy reaches around∼MeV level, the D D fusion reaction probability increases exponentially. The understanding of laser beam propagation and laser energy deposition in clusters is very important to improve neutron yields. As the laser beam propagates through clusters medium, laser energy is absorbed in clusters by ionization of molecules consisting clusters. When the backing pressure of gas increases, the average size of clusters increases and which results in higher energy absorption and earlier termination of laser propagation. We first installed a Michelson interferometer to view laser beam traces in a cluster plume and to measure spatial electron density profiles of a plasma channel which was produced by a laser beam. And then we measured the energy of ions distributed along the plasma channel with a translating slit to select ions from narrow parts of a plasma channel. In our experiments, methane gas was used to produce gas clusters at a room temperature and the energy distribution of proton ions for different gas backing pressure were measured by the time of flight method using dual micro channel plates. By comparing the distribution of ion energies and electron densities, we could understand the condition for effective laser energy delivery to clusters

Enriched gas in clusters and the dynamics of galaxies and clusters: implications for theories of galaxy formation

International Nuclear Information System (INIS)

Binney, J.; Silk, J.

1978-01-01

Recent developments in relation to the origin of galaxies are cited: the discovery that the intergalactic medium which seems to pervade rich clusters of galaxies has an iron abundance that lies within an order of magnitude of the solar value; the discovery that elliptical galaxies rotate much more slowly than the models of these galaxies had predicted; and the results of studies of cosmological infall in the context of the formation of galaxies and galaxy clusters, which have shown that the resulting density profile is fairly insensitive to initial conditions. After discussing the implications of these recent observations of X-ray clusters and of the rotation of elliptical galaxies, an attempt is made to construct a picture of the formation of elliptical and spiral galaxies in which galaxies form continuously from redshift z approximately 100 onwards. It is suggested that at a redshift z of roughly 5, a fundamental change occurred in the manner in which the cosmic material fragmented into stellar objects. It seems possible that explanations of a variety of puzzling aspects of galactic evolution, including the formation of Population I disks, the origin of the hot intracluster gas, the mass-to-light ratio stratification of galaxies, and the nature of the galaxy luminosity function, should all be sought in the context of this change of regime. Some remarks are made about gas in poor groups of galaxies and the interaction of disk galaxies with their environments. (U.K.)

Bepaling van de kwaliteit van reinigingsprocessen.

NARCIS (Netherlands)

Terpstra, P.M.J.

1993-01-01

Ingegaan wordt op de operationalisering van het begrip schoon voor verschillende toepassingen. Daarna worden twee recent ontwikkelde onderzoekmethoden gepresenteerd voor de meting van respectievelijk het reinigingseffect van textiel reinigen en het reinigen van harde vloeroppervlakken en enkele met

Verbeteren van functionele fitheid van brandweermensen

NARCIS (Netherlands)

van Orden, Claudia Y.D.

Posterpresentatie over IAG4-project 'Functional Fitness Monitor', een methodiek voor het verbeteren van functionele fitheid van brandweermensen door een combinatie van meten, presenteren van feedback en coaching. Gepresenteerd op Symposium Healthy Work: Good for Business, gehouden op 29 april 2016

Role of shape and quadrupole deformation of parents in the cluster emission of rare earth nuclei

International Nuclear Information System (INIS)

Girija, K.K.; Joseph, Antony

2014-01-01

The nuclear structure effects on α decay and cluster emission are investigated in the case of even–even rare earth nuclei 150–160 Dy, 150–160 Er, 150–160 Yb, 158,162,166–176 Hf, 160,164–178 W and 162,166,170–180 Os. The role of shape and deformation of parent nuclei in the decay rate is studied by taking the Coulomb and proximity potentials as the interacting barrier for the post scission configuration. The quadrupole deformation of parent nuclei causes a slight change in the half-life of α emissions, but it affects the rate of heavy cluster emissions significantly. Prolate deformation of parents enhances cluster emission, while an oblate deformation slows down the decay. Shape and deformation of parent nuclei causes change in the branching ratio also. A prolate deformation increases the branching ratio, whereas an oblate deformation reduces it. Highest branching ratio is predicted at N ∼ 90. (author)

Electronic and atomic impacts on large clusters

International Nuclear Information System (INIS)

Gspann, J.

1982-01-01

Describing first the generation and properties of molecular beams of large Van der Waals clusters such as speed distribution, cluster size distribution, and internal temperature of the clusters, the review then features the results of electronic impacts on large clusters: metastable electronic cluster excitations, ejection of positive cluster ions of less than 100 atoms from much larger parent clusters, and ionization of the large clusters. Atomic impacts at thermal energies are treated with respect to the scattering cross section of the clusters, their drag coefficient in free molecular flow, and the peculiarities of impacts on helium clusters of either isotope. (Auth.)

MAPPING THE GAS TURBULENCE IN THE COMA CLUSTER: PREDICTIONS FOR ASTRO-H

Energy Technology Data Exchange (ETDEWEB)

ZuHone, J. A. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Markevitch, M. [Astrophysics Science Division, X-ray Astrophysics Laboratory, Code 662, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Zhuravleva, I. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, California 94305-4085 (United States)

2016-02-01

Astro-H will be able for the first time to map gas velocities and detect turbulence in galaxy clusters. One of the best targets for turbulence studies is the Coma cluster, due to its proximity, absence of a cool core, and lack of a central active galactic nucleus. To determine what constraints Astro-H will be able to place on the Coma velocity field, we construct simulated maps of the projected gas velocity and compute the second-order structure function, an analog of the velocity power spectrum. We vary the injection scale, dissipation scale, slope, and normalization of the turbulent power spectrum, and apply measurement errors and finite sampling to the velocity field. We find that even with sparse coverage of the cluster, Astro-H will be able to measure the Mach number and the injection scale of the turbulent power spectrum—the quantities determining the energy flux down the turbulent cascade and the diffusion rate for everything that is advected by the gas (metals, cosmic rays, etc.). Astro-H will not be sensitive to the dissipation scale or the slope of the power spectrum in its inertial range, unless they are outside physically motivated intervals. We give the expected confidence intervals for the injection scale and the normalization of the power spectrum for a number of possible pointing configurations, combining the structure function and velocity dispersion data. Importantly, we also determine that measurement errors on the line shift will bias the velocity structure function upward, and show how to correct this bias.

Mapping the Gas Turbulence in the Coma Cluster: Predictions for Astro-H

Science.gov (United States)

ZuHone, J. A.; Markevitch, M.; Zhuravleva, I.

2016-01-01

Astro-H will be able for the first time to map gas velocities and detect turbulence in galaxy clusters. One of the best targets for turbulence studies is the Coma cluster, due to its proximity, absence of a cool core, and lack of a central active galactic nucleus. To determine what constraints Astro-H will be able to place on the Coma velocity field, we construct simulated maps of the projected gas velocity and compute the second-order structure function, an analog of the velocity power spectrum. We vary the injection scale, dissipation scale, slope, and normalization of the turbulent power spectrum, and apply measurement errors and finite sampling to the velocity field. We find that even with sparse coverage of the cluster, Astro-H will be able to measure the Mach number and the injection scale of the turbulent power spectrum-the quantities determining the energy flux down the turbulent cascade and the diffusion rate for everything that is advected by the gas (metals, cosmic rays, etc.). Astro-H will not be sensitive to the dissipation scale or the slope of the power spectrum in its inertial range, unless they are outside physically motivated intervals. We give the expected confidence intervals for the injection scale and the normalization of the power spectrum for a number of possible pointing configurations, combining the structure function and velocity dispersion data. Importantly, we also determine that measurement errors on the line shift will bias the velocity structure function upward, and show how to correct this bias.

Pulse-driven micro gas sensor fitted with clustered Pd/SnO2 nanoparticles.

Science.gov (United States)

Suematsu, Koichi; Shin, Yuka; Ma, Nan; Oyama, Tokiharu; Sasaki, Miyuki; Yuasa, Masayoshi; Kida, Tetsuya; Shimanoe, Kengo

2015-08-18

Real-time monitoring of specific gas concentrations with a compact and portable gas sensing device is required to sense potential health risk and danger from toxic gases. For such purposes, we developed an ultrasmall gas sensor device, where a micro sensing film was deposited on a micro heater integrated with electrodes fabricated by the microelectromechanical system (MEMS) technology. The developed device was operated in a pulse-heating mode to significantly reduce the heater power consumption and make the device battery-driven and portable. Using clustered Pd/SnO2 nanoparticles, we succeeded in introducing mesopores ranging from 10 to 30 nm in the micro gas sensing film (area: ϕ 150 μm) to detect large volatile organic compounds (VOCs). The micro sensor showed quick, stable, and high sensor responses to toluene at ppm (parts per million) concentrations at 300 °C even by operating the micro heater in a pulse-heating mode where switch-on and -off cycles were repeated at one-second intervals. The high performance of the micro sensor should result from the creation of efficient diffusion paths decorated with Pd sensitizers by using the clustered Pd/SnO2 nanoparticles. Hence we demonstrate that our pulse-driven micro sensor using nanostructured oxide materials holds promise as a battery-operable, portable gas sensing device.

Resistivity and magnetoresistivity of amorphous rare-earth alloys

Science.gov (United States)

Borchi, E.; Poli, M.; De Gennaro, S.

1982-05-01

The resistivity and magnetoresistivity of amorphous rare-earth alloys are studied starting from the general approach of Van Peski-Tinbergen and Dekker. The random axial crystal-field and the magnetic correlations between the rare-earth ions are consistently taken into account. The characteristic features of the available experimental data are explained both of the case of random ferromagnetic and antiferromagnetic order.

Studies of the charge instabilities in the complex nano-objects: clusters and bio-molecular systems

International Nuclear Information System (INIS)

Manil, B.

2007-11-01

For the last 6 years, my main research works focused on i) the Coulomb instabilities and the fragmentation processes of fullerenes and clusters of fullerenes ii) the stability and the reactivity of complex bio-molecular systems. Concerning the clusters of fullerenes, which are van der Waals type clusters, we have shown that the multiply charged species, obtained in collisions with slow highly charged ions, keep their structural properties but become very good electric conductor. In another hand, with the aim to understand the role of the biologic environment at the molecular scale in the irradiation damage of complex biomolecules, we have studied the charge stabilities of clusters of small biomolecules and the dissociation processes of larger nano-hydrated biomolecules. Theses studies have shown that first, specific molecular recognition mechanisms continue to exist in gas phase and secondly, a small and very simple biochemical environment is enough to change the dynamics of instabilities. (author)

Classical photodissociation dynamics with Bohr quantization: Application to the fragmentation of a van der Waals cluster

International Nuclear Information System (INIS)

Arbelo-González, W.; Bonnet, L.; Larrégaray, P.; Rayez, J.-C.; Rubayo-Soneira, J.

2012-01-01

Graphical abstract: A recent classical description of photodissociation dynamics in a quantum spirit is applied for the first time to a realistic process, the fragmentation of NeBr 2 . Highlights: ► The photo-dissociation of NeBr 2 is studied by means of two approaches. ► The first is the standard classical one with Gaussian binning. ► The second is a new method applied for the first time to a realistic system. ► The new method leads to exactly the same results as the standard one. ► However, it requires about 10 times less trajectories in the present case. - Abstract: The recent classical dynamical approach of photodissociations with Bohr quantization [L. Bonnet, J. Chem. Phys. 133 (2010) 174108] is applied for the first time to a realistic process, the photofragmentation of the van der Waals cluster NeBr 2 . We illustrate the fact that this approach, formally equivalent to the standard one, may be numerically much more efficient.

A theoretical study of water equilibria: the cluster distribution versus temperature and pressure for (H2O)n, n = 1-60, and ice.

Science.gov (United States)

Lenz, Annika; Ojamäe, Lars

2009-10-07

The size distribution of water clusters at equilibrium is studied using quantum-chemical calculations in combination with statistical thermodynamics. The necessary energetic data is obtained by quantum-chemical B3LYP computations and through extrapolations from the B3LYP results for the larger clusters. Clusters with up to 60 molecules are included in the equilibrium computations. Populations of different cluster sizes are calculated using both an ideal gas model with noninteracting clusters and a model where a correction for the interaction energy is included analogous to the van der Waals law. In standard vapor the majority of the water molecules are monomers. For the ideal gas model at 1 atm large clusters [56-mer (0-120 K) and 28-mer (100-260 K)] dominate at low temperatures and separate to smaller clusters [21-22-mer (170-280 K) and 4-6-mer (270-320 K) and to monomers (300-350 K)] when the temperature is increased. At lower pressure the transition from clusters to monomers lies at lower temperatures and fewer cluster sizes are formed. The computed size distribution exhibits enhanced peaks for the clusters consisting of 21 and 28 water molecules; these sizes are for protonated water clusters often referred to as magic numbers. If cluster-cluster interactions are included in the model the transition from clusters to monomers is sharper (i.e., occurs over a smaller temperature interval) than when the ideal-gas model is used. Clusters with 20-22 molecules dominate in the liquid region. When a large icelike cluster is included it will dominate for temperatures up to 325 K for the noninteracting clusters model. Thermodynamic properties (C(p), DeltaH) were calculated with in general good agreement with experimental values for the solid and gas phase. A formula for the number of H-bond topologies in a given cluster structure is derived. For the 20-mer it is shown that the number of topologies contributes to making the population of dodecahedron-shaped cluster larger

Online cluster-finding algorithms for the PANDA electromagnetic calorimeter

NARCIS (Netherlands)

Tiemens, Marcel

2017-01-01

Om zeldzame processen zoals de vorming van exotische deeltjes te kunnen bestuderen, is het PANDA experiment opgezet. Om de grote hoeveelheden data te kunnen verwerken, verwerken de subsystemen de data voor. Een voorbeeld is het algoritme om online naar clusters te zoeken in de data van de

On small clusters

International Nuclear Information System (INIS)

Bernardes, N.

1984-01-01

A discussion is presented of zero-point motion effects on the binding energy of a small cluster of identical particles interacting through short range attractive-repulsive forces. The model is appropriate to a discussion of both Van der Waals as well as nuclear forces. (Author) [pt

The mobilies of chiral molecular cluster ions in He gas

International Nuclear Information System (INIS)

Saito, Kazuyuki; Matoba, Shiro; Koizumi, Tetsuo; Kojima, Takao M; Tanuma, Hajime; Shiromaru, Haruo

2012-01-01

We measured the mobilities of Li + -(2-butanol) and Li + -(limonene) ions in He gas at room temperature using a drift tube mass spectrometer. The zero field mobilities of Li + -(2-Butanol) and Li + -(Limonene) were much lower than the polarization limit, indicating that the geometric collision cross-sections between the cluster ions and He atom were larger than the cross-sections predicted by the presence of a polarization force alone.

Monitoring of the natural gas exploitation in the Wadden Sea from the locations Moddergat, Lauwersoog and Vierhuizen, Netherlands. Advice of the Audit Committee on method for monitoring and null-measurement; Monitoring van de aardgaswinning onder de Waddenzee vanaf de locaties Moddergat, Lauwersoog en Vierhuizen. Advies van de Auditcommissie over de opzet van de monitoring en de nulmeting

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-12-21

The Dutch governmental decree ('Rijksprojectenbesluit') on the project for natural gas exploitation in the Wadden Sea for the locations Moddergat, Lauwersoog Vierhuizen gives the Dutch Petroleum Company (NAM) the possibility to produce natural gas under specific conditions in the Wadden Sea area from the six fields Moddergat, Nes, Lauwersoog C, Lauwersoog West, Lauwersoog East and Vierhuizen East. The precondition is that the (dynamic) nature in and around the Wadden Sea is not affected by subsidence as a result of the gas exploitation. For this, the NAM must monitor the subsidence and the nature values and report annually to the Dutch government. Also in the Rijksprojectbesluit it is determined that the Commission for Environmental Impact Assessment (EIA), as the independent auditor, will annually advise the responsible ministers on the EIA-report. This is the first recommendation of the Audit Committee for exploitation of natural gas in the Wadden Sea which in particular deals with the method for the monitoring and baseline measurement. [Dutch] Het Rijksprojectbesluit Gaswinning onder de Waddenzee vanaf de locaties Moddergat, Lauwersoog en Vierhuizen geeft de Nederlandse Aardolie Maatschappij (NAM) de mogelijkheid om onder randvoorwaarden aardgas te produceren in het Waddenzeegebied uit de zes velden Moddergat, Nes, Lauwersoog C, Lauwersoog West, Lauwersoog Oost en Vierhuizen Oost. De randvoorwaarde is dat de (dynamische) natuur in en rondom de Waddenzee niet wordt aangetast door bodemdaling als gevolg van de gaswinning. Daarvoor moet de NAM de bodemdaling en de natuurwaarden monitoren en jaarlijks rapporteren aan de Nederlandse overheid. Ook is in het Rijksprojectbesluit bepaald dat de Commissie voor de milieueffectrapportage (m.e.r.) als onafhankelijke auditor de verantwoordelijke ministers jaarlijks zal adviseren over deze Rapportage. Dit is het eerste advies van de Auditcommissie gaswinning onder de Waddenzee waarin specifiek wordt ingegaan op de

Oral manifestations of Ellis-van Creveld syndrome

Directory of Open Access Journals (Sweden)

Ritesh Kalaskar

2012-01-01

Full Text Available Ellis-van Creveld syndrome is a rare autosomal-recessive disorder characterized by short limbs, post-axial polydactyly, ectodermal dysplasia, edentulous mandibular incisor region, absence of mucobuccal fold, congenitally missing teeth, slight serrations of the alveolar ridge and multiple small alveolar notches. The clinical report not only describes the classical oral and dental manifestations of Ellis-van Creveld syndrome but also presents unusual findings such as single-rooted and funnel-shaped primary first molars, single conical roots of primary second molars and taurodontisum, which must be considered in the differential diagnostic criteria to avoid misdiagnosis of syndromes. The article also discusses the differential diagnosis and preventive and therapeutic oral health care for these patients. The management of Ellis-van Creveld syndrome is multidisciplinary and, therefore, the oral health care provider should get updated with latest knowledge for timely referral to prevent the patient from further complications of heart defect and bony deformity.

Catalytic activity of Cu4-cluster to adsorb H2S gas: h-BN nanosheet

Science.gov (United States)

Kansara, Shivam; Gupta, Sanjeev K.; Sonvane, Yogesh

2018-05-01

We have investigated the electronic properties, adsorptions strength and charge transfer using first principles calculations using density functional theory (DFT). The hexagonal boron nitride (h-BN) substrate shows metallic behavior, which helps to enhance the absorption process. The adsorption of three different orientations (S, D and T) of the H2S gas molecules to analyze the maximum adsorption strength from them onto a copper cluster (Cu4) based on h-BN nanosheet. The maximum adsorption energy of the H2S gas molecule is -1.50 eV for the S orientation and for D and U, it is -0.71 eV and -0.78 eV, respectively. The results show that Cu4 cluster helps to capture H2S gas from the environment and results are useful for the cleaning environment from the toxic gases.

Media effects on the optical absorption spectra of silver clusters embedded in rara gas matrices

International Nuclear Information System (INIS)

Fedrigo, S.; Harbich, W.; Buttet, J.

1993-01-01

The optical absorption of small mass selected Ag n -clusters (n=7, 11, 15, 21) embedded in solid Ar, Kr and Xe has been measured. The absorption spectra show 1 to 3 major peaks between 3 and 4.5 eV, depending on the cluster size. Changing the matrix gas Ar→Kr→Xe induces a redshift which is comparable for all sizes studied and does not affect the main structure of the absorption spectra. We propose a scheme to estimate the gas phase value of the absorption energies which is in fair agreement with an estimation obtained by a simple model based on a Drude metal. (author). 10 refs, 2 figs

Dislocation Structure and Mobility in Hcp Rare-Gas Solids: Quantum versus Classical

Directory of Open Access Journals (Sweden)

Santiago Sempere

2018-01-01

Full Text Available We study the structural and mobility properties of edge dislocations in rare-gas crystals with the hexagonal close-packed (hcp structure by using classical simulation techniques. Our results are discussed in the light of recent experimental and theoretical studies on hcp 4 He, an archetypal quantum crystal. According to our simulations classical hcp rare-gas crystals present a strong tendency towards dislocation dissociation into Shockley partials in the basal plane, similarly to what is observed in solid helium. This is due to the presence of a low-energy metastable stacking fault, of the order of 0.1 mJ/m 2 , that can get further reduced by quantum nuclear effects. We compute the minimum shear stress that induces glide of dislocations within the hcp basal plane at zero temperature, namely, the Peierls stress, and find a characteristic value of the order of 1 MPa. This threshold value is similar to the Peierls stress reported for metallic hcp solids (Zr and Cd but orders of magnitude larger than the one estimated for solid helium. We find, however, that in contrast to classical hcp metals but in analogy to solid helium, glide of edge dislocations can be thermally activated at very low temperatures, T∼10 K, in the absence of any applied shear stress.

The origin of the selectivity and activity of ruthenium-cluster catalysts for fuel-cell feed-gas purification: a gas-phase approach.

Science.gov (United States)

Lang, Sandra M; Bernhardt, Thorsten M; Krstić, Marjan; Bonačić-Koutecký, Vlasta

2014-05-19

Gas-phase ruthenium clusters Ru(n)(+) (n=2-6) are employed as model systems to discover the origin of the outstanding performance of supported sub-nanometer ruthenium particles in the catalytic CO methanation reaction with relevance to the hydrogen feed-gas purification for advanced fuel-cell applications. Using ion-trap mass spectrometry in conjunction with first-principles density functional theory calculations three fundamental properties of these clusters are identified which determine the selectivity and catalytic activity: high reactivity toward CO in contrast to inertness in the reaction with CO2; promotion of cooperatively enhanced H2 coadsorption and dissociation on pre-formed ruthenium carbonyl clusters, that is, no CO poisoning occurs; and the presence of Ru-atom sites with a low number of metal-metal bonds, which are particularly active for H2 coadsorption and activation. Furthermore, comprehensive theoretical investigations provide mechanistic insight into the CO methanation reaction and discover a reaction route involving the formation of a formyl-type intermediate. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Core level photoelectron spectroscopy probed heterogeneous xenon/neon clusters

International Nuclear Information System (INIS)

Pokapanich, Wandared; Björneholm, Olle; Öhrwall, Gunnar; Tchaplyguine, Maxim

2017-01-01

Binary rare gas clusters; xenon and neon which have a significant contrariety between sizes, produced by a co-expansion set up and have been studied using synchrotron radiation based x-ray photoelectron spectroscopy. Concentration ratios of the heterogeneous clusters; 1%, 3%, 5% and 10% were controlled. The core level spectra were used to determine structure of the mixed cluster and analyzed by considering screening mechanisms. Furthermore, electron binding energy shift calculations demonstrated cluster aggregation models which may occur in such process. The results showed that in the case of low mixing ratios of 3% and 5% of xenon in neon, the geometric structures exhibit xenon in the center and xenon/neon interfaced in the outer shells. However, neon cluster vanished when the concentration of xenon was increased to 10%. - Highlights: • Co-expansion setup is suitable for producing binary Xe/Ne clusters. • Appropriate temperature, pressure, and mixing ratios should be strictly controlled. • Low mixing ratio, Xe formed in the core and Xe/Ne interfacing in the outer shell. • High mixing ratio, only pure Xe clusters were detected.

NOAA Mobile Laboratory Measures Oil and Gas Emissions

Science.gov (United States)

Kofler, J. D.; Petron, G.; Dube, W. P.; Edwards, P. M.; Brown, S. S.; Geiger, F.; Patrick, L.; Crepinsek, S.; Chen, H.; Miller, B. R.; Montzka, S. A.; Lang, P. M.; Newberger, T.; Higgs, J. A.; Sweeney, C.; Guenther, D.; Karion, A.; Wolter, S.; Williams, J.; Jordan, A.; Tans, P. P.; Schnell, R. C.

2012-12-01

A van capable of continuous real time measurements of CH4 , CO2, CO, Water Vapor, Ozone, NO, NO2, Volatile Organic Compounds VOCs including aromatics and other traces gases was driven in the oil and gas fields of the Uintah Basin in northeastern Utah. Compressor Stations, processing plants, oil and gas well heads. Separators, condensate tanks, evaporation pond disposal facilities, holding tanks, hydraulic fracturing sites, gas pipelines and more were studied using the van. The mobile measurements provide a powerful tool to get to the source of the emissions and reveal the unique chemical signature of each of the stages and components of oil and gas production as well as the overall basin and background gas concentrations. In addition to a suite of gas analyzers, the van includes a meteorological system (temperature, humidity, and wind speed and direction), GPS tracking, flask sampling system and a batter power system. Aspects of the vans hardware, sampling methods and operations are discussed along with a few highlights of the measurements.

Verdeling van oxytetraxycline (afkomstig van versleping) in diervoeders

NARCIS (Netherlands)

Stolker, A.A.M.; Zuidema, T.; Egmond, van H.J.; Jong, de J.; Haelermans, P.J.M.; Hooglugt, J.H.

2012-01-01

De laatste jaren is er een toenemende aandacht voor de mogelijke bijdrage van therapeutisch gebruik van antibiotica in de dierhouderij op de ontwikkeling van antimicrobiële resistentie. Een additionele bron van blootstelling van landbouwhuisdieren aan antibiotica is versleping via diervoeders. In

An optimal design of cluster spacing intervals for staged fracturing in horizontal shale gas wells based on the optimal SRVs

Directory of Open Access Journals (Sweden)

Lan Ren

2017-09-01

Full Text Available When horizontal well staged cluster fracturing is applied in shale gas reservoirs, the cluster spacing is essential to fracturing performance. If the cluster spacing is too small, the stimulated area between major fractures will be overlapped, and the efficiency of fracturing stimulation will be decreased. If the cluster spacing is too large, the area between major fractures cannot be stimulated completely and reservoir recovery extent will be adversely impacted. At present, cluster spacing design is mainly based on the static model with the potential reservoir stimulation area as the target, and there is no cluster spacing design method in accordance with the actual fracturing process and targets dynamic stimulated reservoir volume (SRV. In this paper, a dynamic SRV calculation model for cluster fracture propagation was established by analyzing the coupling mechanisms among fracture propagation, fracturing fluid loss and stress. Then, the cluster spacing was optimized to reach the target of the optimal SRVs. This model was applied for validation on site in the Jiaoshiba shale gasfield in the Fuling area of the Sichuan Basin. The key geological engineering parameters influencing the optimal cluster spacing intervals were analyzed. The reference charts for the optimal cluster spacing design were prepared based on the geological characteristics of south and north blocks in the Jiaoshiba shale gasfield. It is concluded that the cluster spacing optimal design method proposed in this paper is of great significance in overcoming the blindness in current cluster perforation design and guiding the optimal design of volume fracturing in shale gas reservoirs. Keywords: Shale gas, Horizontal well, Staged fracturing, Cluster spacing, Reservoir, Stimulated reservoir volume (SRV, Mathematical model, Optimal method, Sichuan basin, Jiaoshiba shale gasfield

Orbital alignment effects in near-resonant Rydberg atoms-rare gas collisions

International Nuclear Information System (INIS)

Isaacs, W.A.; Morrison, M.A.

1993-01-01

Recent experimental and theoretical studies of near-resonant energy transfer collisions involving rare-gas atoms and alkali or alkaline earth atoms which have been initially excited to an aligned state via one or more linearly polarized rasters have yielded a wealth of insight into orbital alignment and related effects. We have extended this inquiry to initially aligned Rydberg states, examining state-to-state and alignment-selected cross sections using quantum collision theory augmented by approximations appropriate to the special characteristics of the Rydberg state (e.g., the quasi-free-electron model and the impulse approximation)

GAS SURFACE DENSITY, STAR FORMATION RATE SURFACE DENSITY, AND THE MAXIMUM MASS OF YOUNG STAR CLUSTERS IN A DISK GALAXY. II. THE GRAND-DESIGN GALAXY M51

International Nuclear Information System (INIS)

González-Lópezlira, Rosa A.; Pflamm-Altenburg, Jan; Kroupa, Pavel

2013-01-01

We analyze the relationship between maximum cluster mass and surface densities of total gas (Σ gas ), molecular gas (Σ H 2 ), neutral gas (Σ H I ), and star formation rate (Σ SFR ) in the grand-design galaxy M51, using published gas data and a catalog of masses, ages, and reddenings of more than 1800 star clusters in its disk, of which 223 are above the cluster mass distribution function completeness limit. By comparing the two-dimensional distribution of cluster masses and gas surface densities, we find for clusters older than 25 Myr that M 3rd ∝Σ H I 0.4±0.2 , whereM 3rd is the median of the five most massive clusters. There is no correlation withΣ gas ,Σ H2 , orΣ SFR . For clusters younger than 10 Myr, M 3rd ∝Σ H I 0.6±0.1 and M 3rd ∝Σ gas 0.5±0.2 ; there is no correlation with either Σ H 2 orΣ SFR . The results could hardly be more different from those found for clusters younger than 25 Myr in M33. For the flocculent galaxy M33, there is no correlation between maximum cluster mass and neutral gas, but we have determined M 3rd ∝Σ gas 3.8±0.3 , M 3rd ∝Σ H 2 1.2±0.1 , and M 3rd ∝Σ SFR 0.9±0.1 . For the older sample in M51, the lack of tight correlations is probably due to the combination of strong azimuthal variations in the surface densities of gas and star formation rate, and the cluster ages. These two facts mean that neither the azimuthal average of the surface densities at a given radius nor the surface densities at the present-day location of a stellar cluster represent the true surface densities at the place and time of cluster formation. In the case of the younger sample, even if the clusters have not yet traveled too far from their birth sites, the poor resolution of the radio data compared to the physical sizes of the clusters results in measuredΣ that are likely quite diluted compared to the actual densities relevant for the formation of the clusters.

Theoretical Study On The Interaction Between Xenon And Positive Silver Clusters In Gas Phase And On The (001) Chabazite Surface

International Nuclear Information System (INIS)

Hunter, D.

2009-01-01

A systematic study on the adsorption of xenon on silver clusters in the gas phase and on the (001) surface of silver-exchanged chabazite is reported. Density functional theory at the B3LYP level with the cluster model was employed. The results indicate that the dominant part of the binding is the σ donation, which is the charge transfer from the 5p orbital of Xe to the 5s orbital of Ag and is not the previously suggested d π -d π back-donation. A correlation between the binding energy and the degree of σ donation is found. Xenon was found to bind strongly to silver cluster cations and not to neutral ones. The binding strength decreases as the cluster size increases for both cases, clusters in the gas-phase and on the chabazite surface. The Ag + cation is the strongest binding site for xenon both in gas phase and on the chabazite surface with the binding energies of 73.9 and 14.5 kJ/mol, respectively. The results also suggest that the smaller silver clusters contribute to the negative chemical shifts observed in the 129 Xe NMR spectra in experiments.

Selectie van Italiaanse werkwoordsvormen op basis van frequentieonderzoek

NARCIS (Netherlands)

Boer, M.G. de

2009-01-01

SAMENVATTING Dit artikel is een vroege recensie (mei 1972) van het LIF, de frequentielijst van IBM Italia uit 1971. De auteur concentreert zich op de verschillen met het project van Juilland, dat als uitgangspunt voor het LIF heeft gefungeerd. Op grond van de gegevens van het LIF is een basislijst

Is there a Difference in Van Der Waals Interactions between Rare Gas Atoms Adsorbed on Metallic and Semiconducting Single-Walled Carbon Nanotubes?

Energy Technology Data Exchange (ETDEWEB)

Chen, De-Li [Univ. of Pittsburgh, PA (United States). Dept. of Chemical and Petroleum Engineering; Mandeltort, Lynn [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Chemistry; Saidi, Wissam A. [Univ. of Pittsburgh, PA (United States). Dept. of Chemical and Petroleum Engineering; Yates, John T. [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Chemistry; Cole, Milton W. [Pennsylvania State Univ., University Park, PA (United States). Dept of Physics; Johnson, J. Karl [Univ. of Pittsburgh, PA (United States). Dept. of Chemical and Petroleum Engineering; National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

2013-03-01

Differences in polarizabilities of metallic (M) and semiconducting (S) single-walled carbon nanotubes (SWNTs) might give rise to differences in adsorption potentials. We show from experiments and van der Waals-corrected density functional theory (DFT) that binding energies of Xe adsorbed on M- and S-SWNTs are nearly identical. Temperature programmed desorption of Xe on purified M- and S-SWNTs give similar peak temperatures, indicating that desorption kinetics and binding energies are independent of the type of SWNT. Binding energies computed from vdW-corrected DFT are in good agreement with experiments.

Zoninvloed in klimaatregeling courgette spaart gas

NARCIS (Netherlands)

Janse, J.; Buwalda, F.

2005-01-01

Een courgettegewas verbruikt per jaar vrij veel energie: rond 35 kuub gas per vierkante meter. In recent onderzoek van het PPO Naaldwijk bleek dat dit gasverbruik met 15 procent omlaag kan. Dit is te realiseren door de invloed van natuurlijke instraling te verwerken in de klimaatregeling van de

Determination of hydrogen cluster velocities and comparison with numerical calculations

International Nuclear Information System (INIS)

Täschner, A.; Köhler, E.; Ortjohann, H.-W.; Khoukaz, A.

2013-01-01

The use of powerful hydrogen cluster jet targets in storage ring experiments led to the need of precise data on the mean cluster velocity as function of the stagnation temperature and pressure for the determination of the volume density of the target beams. For this purpose a large data set of hydrogen cluster velocity distributions and mean velocities was measured at a high density hydrogen cluster jet target using a trumpet shaped nozzle. The measurements have been performed at pressures above and below the critical pressure and for a broad range of temperatures relevant for target operation, e.g., at storage ring experiments. The used experimental method is described which allows for the velocity measurement of single clusters using a time-of-flight technique. Since this method is rather time-consuming and these measurements are typically interfering negatively with storage ring experiments, a method for a precise calculation of these mean velocities was needed. For this, the determined mean cluster velocities are compared with model calculations based on an isentropic one-dimensional van der Waals gas. Based on the obtained data and the presented numerical calculations, a new method has been developed which allows to predict the mean cluster velocities with an accuracy of about 5%. For this two cut-off parameters defining positions inside the nozzle are introduced, which can be determined for a given nozzle by only two velocity measurements

’n Oorsig van die bepaling van die vroeë bakterisidiese aktiwiteit van verskeie antituberkulosemiddels

Directory of Open Access Journals (Sweden)

P. R. Donald

2003-06-01

Full Text Available Die vroeë bakterisidiese aktiwiteit (VBA van ’n antituberkulosemiddel is die daaglikse afname van M tuberculosis in log10 kolonievormende eenhede per ml sputum, tydens die eerste twee dae van behandeling met die middel. Dit weerspieël die vermoë van ’n middel om aktief metaboliserende organismes in tuberkulose-longholtes te dood. Dit is ’n relatief goedkoop metode om in ’n klein groep pasiënte die antituberkulose-aktiwiteit van ’n middel, binne maande, in vivo te evalueer. Hierdie artikel som ons ondervinding op tydens sewe gepubliseerde VBA-studies, en die bronne van variasie in die prosedure word identifiseer. Die pasiënte in hierdie studies was gemiddeld 33 jaar oud, met ’n gemiddelde gewig van 50 kg en 55% het ekstensiewe of massiewe longaantasting gehad. Die hoogste VBA-waardes (0,50-0,66 is gevind in pasiënte wat isoniasied ontvang het, en die laagste waardes (0,05 en 0,09 respektiewelik was gevind in pasiënte wat die aminoglikosiede amikasien en paromomisien, albei in doserings van 15 mg/kg liggaamsgewig, ontvang het. Die algehele variasie in die VBA van 248 pasiënte was 0,0312, en die variasie toegeskryf aan die proses van sputumproduksie en -versameling was 0,0223. Dit blyk dat die verskillende aspekte van sputumproduksie en -versameling, betrokke by die lewering van ’n verteenwoordigende sputummonster, ’n groter bydrae maak tot variasie tydens die prosedure as die laboratoriumaspekte van die tegniek. Die keuring van pasiënte vir insluiting in VBA-studies, en hulle vermoë om saam te werk om ’n verteenwoordigende sputummonster te produseer, is van deurslaggewende belang in die suksesvolle voltooiing van VBA-studies.

Clustering mechanism of oxocarboxylic acids involving hydration reaction: Implications for the atmospheric models

Science.gov (United States)

Liu, Ling; Kupiainen-Määttä, Oona; Zhang, Haijie; Li, Hao; Zhong, Jie; Kurtén, Theo; Vehkamäki, Hanna; Zhang, Shaowen; Zhang, Yunhong; Ge, Maofa; Zhang, Xiuhui; Li, Zesheng

2018-06-01

The formation of atmospheric aerosol particles from condensable gases is a dominant source of particulate matter in the boundary layer, but the mechanism is still ambiguous. During the clustering process, precursors with different reactivities can induce various chemical reactions in addition to the formation of hydrogen bonds. However, the clustering mechanism involving chemical reactions is rarely considered in most of the nucleation process models. Oxocarboxylic acids are common compositions of secondary organic aerosol, but the role of oxocarboxylic acids in secondary organic aerosol formation is still not fully understood. In this paper, glyoxylic acid, the simplest and the most abundant atmospheric oxocarboxylic acid, has been selected as a representative example of oxocarboxylic acids in order to study the clustering mechanism involving hydration reactions using density functional theory combined with the Atmospheric Clusters Dynamic Code. The hydration reaction of glyoxylic acid can occur either in the gas phase or during the clustering process. Under atmospheric conditions, the total conversion ratio of glyoxylic acid to its hydration reaction product (2,2-dihydroxyacetic acid) in both gas phase and clusters can be up to 85%, and the product can further participate in the clustering process. The differences in cluster structures and properties induced by the hydration reaction lead to significant differences in cluster formation rates and pathways at relatively low temperatures.

Natural resources and geothermal energy in the Netherlands. Annual report 2012. A review of exploration and production activities and underground storage; Delfstoffen en Aardwarmte in Nederland. Jaarverslag 2012. Een overzicht van opsporings- en winningsactiviteiten en van ondergrondse opslag

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-06-15

The annual review reports on the activities and results of exploration and production of hydrocarbons, rock salt and geothermal energy in the Netherlands. Moreover the underground storage of various substances (e.g. natural gas, nitrogen, CO2 and brackish water) is included as well. In this way all the exploration, production and storage activities in the Netherlands and the Netherlands' part of the Continental shelf, related to the realm of the Mining Act, are combined in this report. The first section of the report deals with developments during the year 2012. The section shows the developments in the exploration, production and underground storage of hydrocarbons. It concerns changes in natural gas and oil resource estimates during 2012 and the way these changes affected the situation at 1 January 2013. This section also presents a prognosis for the gas production for the next 25 years. This year the remaining resources of natural gas and oil are reported in accordance with the Petroleum Resource Management System. This system should lead to a uniform classification of all reported resources. Subsequently, a number of tables summarise developments during 2012, with respect to licences and exploration efforts (seismic surveys and wells drilled). This section ends with a summary of the volumes of natural gas, condensate and oil that were produced in 2012. The subsequent chapters report on the exploration for and production of coal, rock salt and geothermal energy and on the underground storage of substances. The second section comprises a large number of annexes that report on the current situation as well as on historical developments during the past decades. Subsequently an overview of the situation as at 1 January 2013 is presented in the final part of the review [Dutch] Het Jaarverslag rapporteert over de activiteiten en resultaten van de opsporing en winning van koolwaterstoffen, steenzout en aardwarmte in Nederland. Daarnaast komt de ondergrondse opslag

Chloroplast DNA haplotype samenstelling van eikenopstanden (categorie "van bekende origine") van de Rassenlijst van Bomen; een aanvullende methode voor identificatie van autochtoniteit

NARCIS (Netherlands)

Buiteveld, J.; Boerwinkel, M.C.; Bovenschen, J.; Kranenborg, K.G.; Vries, de S.M.G.

2005-01-01

Tegenwoordig kan autochtoon materiaal op de Rassenlijst van Bomen geplaatst worden in de categorie `van bekende origine¿ en heeft daardoor een `officiële¿ status. Identificatie van autochtone opstanden blijft echter nog een lastige zaak. Momenteel worden autochtone opstanden geïdentificeerd met de

Heat techniques in the light of the innovation curve. New technology for gas appliances and solar water heaters; Warmtetechnieken in het licht van de innovatiecurve. Nieuwe technologie gezocht voor gastoestel en zonneboilers

Energy Technology Data Exchange (ETDEWEB)

Vollebregt, R.

2012-09-15

The development, market introduction and deployment of new techniques often follows an S-shaped curve. The gas-fired boiler transformed from a conventional apparatus into the current high efficiency boiler. Will the high efficiency electricity boiler be the next breakthrough technique? The electrical and gas heat pumps are fully developed techniques, but this does not apply to their use in Dutch single-family dwellings [Dutch] De ontwikkeling, marktintroductie en toepassing van nieuwe technieken verloopt vaak volgens een S-vormige curve. De gasketel transformeerde van conventioneel toestel naar de huidige hr-ketel. Is de hre-ketel de volgende doorbraaktechniek? De elektrische en de gaswarmtepomp zijn uitontwikkelde technieken, maar nog niet voor de toepassing in een Nederlandse eengezinswoning.

Clinical manifestations of Ellis-van Creveld syndrome

Directory of Open Access Journals (Sweden)

Vinay C

2009-01-01

Full Text Available Ellis-van Creveld syndrome (EVC is a chondro-ectodermal dysplasia characterized by short ribs, polydactyly, growth retardation and ectodermal and heart defects. It is a rare disease complex and very few cases have been reported in dental literature. This condition is inherited as an autosomal recessive trait with variable expression. The present case report describes EVC in a 7-year-old girl, with all the tetrad of cardinal features. We found a rare dental aberration in form; appearance of single conical roots in primary molars. The management of children with EVC is multidisciplinary, with consideration for the high incidence of cardiac defects in these patients.

Biologische effectiviteit van bespuitingen: effecten van druppelgrootte en waterkwaliteit

NARCIS (Netherlands)

Zande, van de J.C.; Schans, van der D.A.; Koster, A.T.J.

2004-01-01

Deze rapportage beschrijft de invloed van watervolume, druppelgrootte en kwaliteit van het tankmengsel op de biologische effectiviteit van bespuitingen. Onder kwaliteit van het tankmengsel wordt in dit verband verstaan: temperatuur, hardheid, pH en zoutgehalte (chloor en ijzerzouten) van de

Structure and bonding in clusters

International Nuclear Information System (INIS)

Kumar, V.

1991-10-01

We review here the recent progress made in the understanding of the electronic and atomic structure of small clusters of s-p bonded materials using the density functional molecular dynamics technique within the local density approximation. Starting with a brief description of the method, results are presented for alkali metal clusters, clusters of divalent metals such as Mg and Be which show a transition from van der Waals or weak chemical bonding to metallic behaviour as the cluster size grows and clusters of Al, Sn and Sb. In the case of semiconductors, we discuss results for Si, Ge and GaAs clusters. Clusters of other materials such as P, C, S, and Se are also briefly discussed. From these and other available results we suggest the possibility of unique structures for the magic clusters. (author). 69 refs, 7 figs, 1 tab

Rare-gas dependence of the self-quenching streamer

International Nuclear Information System (INIS)

Yoshioka, K.; Hashimoto, M.; Koori, N.; Kumabe, I.; Ohgaki, H.; Matoba, M.

1989-01-01

The self-quenching streamer (SQS) mode is understood these days as one of the basic modes of gas counter operation. In the present work, the SQS transition is clearly observed for Ar-, Kr- and Xe-mixtures with CH 4 , C 2 H 6 , C 3 H 8 , isoC 4 H 10 and CO 2 , and for He- and Ne-mixtures with C 2 H 6 , C 3 H 8 and isoC 4 H 10 . For He- and Ne-mixtures with CH 4 or CO 2 , the GM discharge is developed instead of the SQS transition. The avalanche size at the transition voltage decreases, in the order of He-, Ne-, Ar-, Kr- and Xe-mixtures, except for He-mixtures with CH 4 or CO 2 . The mechanisms of the SQS transition proposed by Atac et al. and Zhang have disadvantages in explaining all these results. If the photo-ionization is assumed as in Atac's mechanism, energetic photons whose yield is sufficiently large are needed for the SQS transition. The interaction between metastable states of rare gases proposed by Zhang may be energetically capable of producing electrons for the transition; effects of quenching gas in mixtures cannot be explained by this mechanism. Further investigation is necessary for microscopic processes occurring in the avalanche development. More detailed information is required on the atomic reaction cross sections of photo-ionization, radiative recombination, etc. (N.K.)

Dynamics of exciplex formation in rare gas media

International Nuclear Information System (INIS)

Rojas-Lorenzo, German; Rubayo-Soneira, Jesus; Alberti, Sebastian Fernandez

2009-01-01

A hopping-surface algorithm has been used to simulate the dynamics induced in rare gas matrices due to the photoexcitation ( 1 S 0 → 3 P 1 ) of atomic mercury embedded in them. Especially, the study of the dynamics of an exciplex formation in a model system consisting of solid xenon doped with atomic mercury. The process starts upon the photoexcitation of the Hg atom to its 3 P 1 electronic excited state. Diatomics-in-Molecule approach has been used for constructing the adiabatic potential surfaces. In all trajectories we show that a triatomic Xe-Hg * -Xe complex is formed, but in two conformations: bent and linear. The mechanisms leading to the formation of one or the other are identified. Mainly, are noted the thermal fluctuations of the Hg impurity and the shape of the potential surfaces. Furthermore, we show that non-radiative intrastate relaxation occurs via a conical intersection between the excited state surfaces. The simulated spectra are in very good agreement with the experimental data.

Van doorvoerland naar servicenetwerk; welke rol is voor Agrologistiek Nederland weggegelegd?

NARCIS (Netherlands)

Scheer, F.P.; Groot, J.J.; Snels, J.C.M.A.; Vorst, van der J.G.A.J.

2010-01-01

Het Nederlandse agro-cluster is een belangrijke peiler onder de Nederlandse economie. Haar netto export (export-import) bedraagt ruim 20 miljard euro en vertegenwoordigt circa 50% van de Nederlandse handelsbalans. Hierbinnen vervult de agrologistiek een belangrijke rol, zowel nationaal (toegevoegde

Extra natural gas by foam injection; Extra aardgas door foam-injectie

Energy Technology Data Exchange (ETDEWEB)

De Boer, B.

2008-07-01

The Dutch Petroleum Company (NAM) has further developed an originally American technology for expanding the economic lifespan of gas fields. Injection of environment-friendly foam enables further extraction of natural gas from nearly depleted gas fields. [mk]. [Dutch] De Nederlandse Aardolie Maatschappij (NAM) heeft een van origine Amerikaanse techniek om de economische levensduur van gasvelden te verlengen verder ontwikkeld. Het injecteren van een milieuvriendelijke zeep (foam) maakt het mogelijk om langer aardgas te produceren uit bijna lege gasvelden.

Verslag van de voorstudie: Paddenstoelen bedrijf van de toekomst

NARCIS (Netherlands)

Tuijl, van B.A.J.; Bos, A.P.; Sonnenberg, A.S.M.

2013-01-01

Het rapport ‘Paddenstoelenbedrijf van de toekomst’ is het resultaat van een uitgebreid vooronderzoek en geeft de eerste aanzet tot het creëren van gemeenschappelijke visie van de sector op een betere toekomst voor paddenstoelenkwekerijen. Het rapport doet verslag van een reeks interviews en een

Samenstelling van de vluchtige olie van Origanum vulgare L. ssp. vulgare gedurende de ontwikkeling van de plant

NARCIS (Netherlands)

Maarse, Henk

1971-01-01

INLEIDING EN DOEL VAN HET ONDERZOEK Vele onderzoekers hebben de laatste jaren de vorming van de verbindingen in vluchtige olien van planten bestudeerd door het bepalen van de verandering in de samenstelling van de vluchtige olie tijdens de groei van de plant. Lemli (68) wees als eerste op de

Some aspects of the interaction of photons and electrons with rare gas atoms

International Nuclear Information System (INIS)

Westerveld, W.B.

1979-01-01

Processes for excitation in rare gas atoms are described, due to absorption of photons and bombardment with electrons. The differences and similarities between excitation by absorption of light (spectroscopy) and by electron impact (collision physics) are qualified. Oscillator strengths from the self-absorption of resonance radiation in rare gases are determined. The excitation of 2'P and 3'P states of helium by electrons has been studied by observing excitation cross sections and polarization fractions obtained from XUV radiation. A description is given of a recently completed apparatus to study inelastic electron-atom scattering processes by coincidence techniques. An introduction is given to the theory which relates the parameters describing an excited state of an atom to the angular distribution of the radiation emitted in the decay of the excited state. (Auth.)

Onderzoek naar vermindering van de bijvangst van een boomkortuig

NARCIS (Netherlands)

Marlen, van B.; Ybema, M.S.; Duijn, van J.B.

2005-01-01

In het kader van EU-project RECOVERY werden vergelijkende visserij- en selectiviteitsproeven uitgevoerd in 2002 en 2003 aan boord van MS “Tridens” aan 12 m boomkortuigen. De resultaten van een negental vistuigproeven zijn hier gegeven, gericht op het bepalen van het effect van een grote mazen kap

Electrical and optical properties of thin indium tin oxide films produced by pulsed laser ablation in oxygen or rare gas atmospheres

DEFF Research Database (Denmark)

Thestrup, B.; Schou, Jørgen; Nordskov, A.

1999-01-01

Films of indium tin oxide (ITO) have been produced in different background gases by pulsed laser deposition (PLD). The Films deposited in rare gas atmospheres on room temperature substrates were metallic, electrically conductive, but had poor transmission of visible light. For substrate temperatu......Films of indium tin oxide (ITO) have been produced in different background gases by pulsed laser deposition (PLD). The Films deposited in rare gas atmospheres on room temperature substrates were metallic, electrically conductive, but had poor transmission of visible light. For substrate...

Conceptual design of an angular multiplexed rare-gas-halide laser-fusion driver. Final technical report, 1 August 1979-31 May 1980

International Nuclear Information System (INIS)

Parks, J.H.

1980-11-01

A conceptual definition for angular multiplexed rare gas halide drivers was formulated and several design examples analyzed. Angular multiplexed rare gas-halide lasers, in particular the KrF* laser, can be designed to meet ICF requirements. These lasers are scalable, emit at short wavelengths (KrF* 250 nm), and through the use of optical angular multiplexing, produce the required high energy (approx. 1 to 5 MJ) in a short pulse (approx. 10 nsec) with projected overall efficiency in the range of 5 to 7%

Die Romeinse nastrewing van onsterflikheid deur middel van memoria

Directory of Open Access Journals (Sweden)

D. R. Fouché

1985-05-01

Full Text Available Benewens die omvangryke en nasionale manifestasies van die oorspronklike onsterflikheidsgedagte in die Romeinse gemeenskap, vind ons by die Romein op kleiner skaal in groepe of indiwidueel ’n strewe na onsterflikheid langs die weg van memoria. Soos aangetoon sal word, verskil die pogings van die verskillende groepe radikaal van mekaar, hoewel die strewe en einddoel dieselfde bly, naamlik om deur die daarstelling van memoria op die gebied van woord of daad onsterflikheid te bekom.

Basis for the update of BEES B. Costs and effects of the planned adjustment of the Decree on Emission Limits for Combustion Plants B; Onderbouwing actualisatie BEES B. Kosten en effecten van de voorgenomen wijziging van het besluit emissie-eisen stookinstallaties B

Energy Technology Data Exchange (ETDEWEB)

Kroon, P.; Wetzels, W. [ECN Beleidsstudies, Petten (Netherlands)

2009-01-15

For the Ministry of Housing, Spatial Planning and the Environment (VROM) calculations were made on the effects of an update of the Dutch Emission Limits Combustion Plants Decree (BEES B). BEES B sets NOx emission limits for combustion installations between 0.9 MWth (boilers on gas and oil) and 50 MWth (total on one location). For coal boilers and gas engines, there is no lower capacity limit in BEES B. For gas turbines it is 1 MWe. Although Directive 96/61/EC, concerning integrated pollution prevention and control (the IPPC Directive), is designed for bigger installations, VROM wants to include the emission levels of the Best Available Techniques (BAT) for smaller installations as well. Other changes are the inclusion of wood boilers and new CxHy emission limits for gas engines. Furthermore, emission levels on SO2 and fine particulates (PM10), which currently only exist for coal, are extended to gas, oil and wood combustion. VROM intends to set the lowest level for BEES B at 1 MWth for all installations. Smaller installations will be addressed in other legislation. In the project a separation was made with other policies like BEES A, the Dutch Emissions Guidelines (NER) but not with NOx emission trading (for process emissions and locations with over 20 or 30 MWth on active installations). The trading level for combustion is 40 g NOx/GJ in 2010, but this will be decreased after 2010. [Dutch] Het ministerie van VROM werkt aan een actualisatie van het Besluit Emissie Eisen Stookinstallaties B (BEES B). In het kader hiervan is de afdeling Beleidsstudies van het ECN gevraagd om de te verwachten kosten en effecten van de actualisatie in kaart te brengen. In de berekeningen is er vanuit gegaan dat de wijzigingen van de eisen voor nieuwe installaties ingaan per 1 januari 2009 en voor bestaande installaties zes jaar later op 1 januari 2015. Als basis voor de berekening van de effecten is uitgegaan van het veelgebruikte WLO GE-scenario met bijstellingen voor de sterkere

Het planetarium van Hartog van Laun

Directory of Open Access Journals (Sweden)

Hans Hooijmaaijers

2009-12-01

Full Text Available The instrument maker Hartog van Laun devised a special table for an orrery, a lunarium and a tellurium. Van Laun made these instruments for educational purposes, but what makes his planetariums so interesting is the great variety and accuracy of demonstrations one can perform with them. In this paper I will deal with Van Laun and his instrument makers business. I will outline the design of the planetarium and some of the firm’s other instruments. Furthermore I will demonstrate that the detailed description of the planetarium made by Professor Jan Hendrik van Swinden boosted the spread of the instrument.

From Moscow to Copenhagen. Russian views on climate change; Van Moskou naar Kopenhagen. Russische vergezichten op klimaatverandering

Energy Technology Data Exchange (ETDEWEB)

Van Agt, C.

2009-11-15

To fuel economic recovery and growth Russia will increase oil and gas supplies to the industrialized market economies of the Euro Atlantic in the West and the Asian Pacific growth economies in the East. Despite the post-Soviet economic collapse, Russia is still among the largest emitters of greenhouse gases, after the United States, China and the European Union. Moscow's foreign economic policies are spearheaded by natural gas, a clean burning fossil fuel pivotal to world economic transition to a less carbon intensive 'green' model. Despite the adoption of a new climate-change strategy and Russia's acknowledgement that it must play a responsible role in the run up to the Climate Change Summit in Copenhagen, Moscow's policy position is still aloof, due to geopolitical undercurrents and Russia's particular position in debates on the nature and cost of mitigation measures between industrialized countries and the emerging economies of the developing world. [Dutch] Door het economisch herstel en de economische groei zal Rusland leveringen van olie en gas aan de geindustrialiseerde markt economieen verhogen. Ondanks de economische achteruitgang van de voormalige Sovjet Unie is Rusland, na de Verenigde Staten, China en de Europese Unie, nog steeds een van de grootste uitstoters van broeikasgassen. Het buitenlandse economische beleid van Moskou wordt sterk bepaald door aardgas, dat een belangrijke rol speelt in de mondiale economische overgang naar een minder koolstofintensief 'groen' model. Ondanks de goedkeuring van een nieuw klimaat-verandering-strategie en de Russische erkenning dat het een verantwoordelijke rol moet spelen in de aanloop naar de klimaatveranderingtop in Kopenhagen, is het Russische beleid nog steeds afstandelijk, als gevolg van geopolitieke onderstromen en de bijzondere positie die Rusland inneemt in de debatten over de aard en de kosten van mitigerende maatregelen tussen de geindustrialiseerde landen en de

Fe-Cluster Compounds of Chalcogenides: Candidates for Rare-Earth-Free Permanent Magnet and Magnetic Nodal-Line Topological Material.

Science.gov (United States)

Zhao, Xin; Wang, Cai-Zhuang; Kim, Minsung; Ho, Kai-Ming

2017-12-04

Fe-cluster-based crystal structures are predicted for chalcogenides Fe 3 X 4 (X = S, Se, Te) using an adaptive genetic algorithm. Topologically different from the well-studied layered structures of iron chalcogenides, the newly predicted structures consist of Fe clusters that are either separated by the chalcogen atoms or connected via sharing of the vertex Fe atoms. Using first-principles calculations, we demonstrate that these structures have competitive or even lower formation energies than the experimentally synthesized Fe 3 X 4 compounds and exhibit interesting magnetic and electronic properties. In particular, we show that Fe 3 Te 4 can be a good candidate as a rare-earth-free permanent magnet and Fe 3 S 4 can be a magnetic nodal-line topological material.

Transmission electron microscope examination of rare-gas bubbles in metals: analysis of observed contrast effects

International Nuclear Information System (INIS)

Levy, V.

1964-01-01

Metallic samples containing rare gas bubbles have been examined by transmission electron microscopy. The different features of the contrast patterns of the bubbles have been explained by the dynamical theory of contrast, assuming that the bubble behaves as a hole in the metal. Experimental results are in good agreement with the theory. (author) [fr

‘n Kritiese bespreking van roskam se seining van apartheid as grondslag van die Suid-afrikaanse samelewing

Directory of Open Access Journals (Sweden)

N. van Loggerenberg

1963-03-01

Full Text Available Segregasie is al deur vele ondersoekers histories tot ’n tradisie uit die stigtingsjaar 1652 met die aankoms van Jan van Riebeeck herlei. Roskam sion dit egter as 'n beleid wat veel later aanvaar is. Hy sien dit as beleid wat bepaalde groepe van die bevolking as 'n politieke eenheid, kragtens ’n sosiale hiërargie, van mekaar wil afskei, isoleer. Dit is vir  hom duidelik dat die politieke eenheid van Ordinansie 50 van 1828 nooit werklikheid geword het nie, en die tradisie van blanke heerskappy pas vir liom as heleid beter in die huidige situasic as segregasie. Roskam is dan van oordeel dat ..white supremacy” daarom die juiste en omskrywende betekenis van segregasie is.

Detectie van ziektesymptomen met behulp van fluorescentiebeelden

NARCIS (Netherlands)

Loon, van P.C.C.

2004-01-01

Rapport over de positie van de biologische paddestoelenteelt op intersectoraal en (inter)-regionaal niveau. Het overzicht in tabel- en schemavorm van de stromen grondstoffen en producten verduidelijkt de intersectorale positie van de champignonteelt. Dit kan een aanzet zijn bij het signaleren en

Een revisie van de taxonomie van gifkikkers

NARCIS (Netherlands)

Poelman, E.H.

2007-01-01

Recent kwam het lang verwachte ruim tweehonderdvijftig pagina`s tellende manuscript uit met daarin een revisie van de taxonomie van gifkikkers. De auteurs onder leiding van Taran Grant stellen een nieuwe taxonomie voor, die de familie Dendrobatidae met haar tien algemener geaccepteerde genera

De toekomst van flex : een onderzoek van tno naar flexstrategieën van Nederlandse bedrijven

NARCIS (Netherlands)

Verbiest, S.E.; Goudswaard, A.; Wijk, E.B. van

2014-01-01

In 2020 zal het personeelsbestand van organisaties voor 30% uit flexkrachten bestaan. Op dit moment is dat 25%. Dit blijkt uit een onderzoek van TNO onder 900 ondernemingen in opdracht van de ABU (Algemene Bond Uitzendondernemingen). Het blijkt dat met name organisaties die al gebruikmaken van

De trek van kruiden van volgroeid wortelmateriaal : handleiding van A tot Z in beknopte vorm

NARCIS (Netherlands)

Wijk, van C.A.P.

2005-01-01

Deze teelthandleiding richt zich op de trek van vooral dragon, krulpeterselie, rucola en munt, uitgaande van wortelmateriaal dat in de vollegrond wordt geteeld. Deze forcering richt zich zowel op aanbod van kruiden in potjes als de meermalige oogst van het gesneden product in een kas of een

Numerieke simulatie van de blastbelasting op vlucht MH17 van Malaysia Airlines als gevolg van de detonatie van een gevechtslading (U)

NARCIS (Netherlands)

2015-01-01

De Onderzoeksraad voor Veiligheid (OVV) onderzoekt de crash van vlucht MH17 van Malaysia Airlines die plaatsvond op donderdag 17 juli 2014 in de regio Donetsk (Oekraïne). De OVV wil een duidelijk beeld geven van de oorzaak van de crash. Een mogelijke oorzaak is fatale schade aan het vliegtuig als

Rare gas constraints on the history of Boulder 1, Station 2, Apollo 17

International Nuclear Information System (INIS)

Leich, D.A.; Kahl, S.B.; Kirschbaum, A.R.; Niemeyer, S.; Phinney, D.

1975-01-01

Rare gas isotopic analyses have been performed on both pile-irradiated and unirradiated samples from Boulder 1, Station 2. Two samples from rock 72255, the Civet Cat clast and a sample of adjacent breccia, have concordant 40 Ar- 39 Ar ages of 3.99 +- 0.03 b.y. and 4.01 +- 0.03 b.y., respectively. Several samples from rock 72275 have complex thermal release patterns with no datable features, but an intermediate temperature plateau from the dark rim material of the Marble Cake clast yields an age of 3.99 +- 0.03 b.y., indistinguishable from the age of rock 72255. We regard these ages as upper limits on the time of the Serenitatis basin-forming event. The absence of fossil solar-wind trapped gases in the breccia samples implies that a prior existence for the boulder as near-surface regolith material can be regarded as extremely unlikely. Instead, the small trapped rare-gas components have isotopic and elemental compositions diagnostic of the terrestrial-type trapped component which has previously been identified in several Apollo 16 breccias and in rock 14321. Excess fission Xe is found in all Boulder 1 samples in approximately 1:1 proportions with Xe from spontaneous fission of 238 U. This excess fission Xe is attributed to spontaneous fission of 244 Pu in situ. Cosmic-ray exposure ages for samples from rocks 72215 and 72255 are concordant with mean 81 Kr-Kr exposure ages of 41.4 +- 1.4 m.y. and 44.1 +- 3.3 m.y., respectively. However, a distinctly different 81 Kr-Kr exposure age of 52.5 +- 1.4 m.y. is obtained for samples from rock 72275. A two-stage exposure model is developed to account for this discordance and for the remaining cosmogenic rare-gas data. The first stage was initiated at least 55 m.y. ago, probably as a result of the excavation of the boulder source-crop. A discrete change in shielding depths approx. 35 m.y. ago probably corresponds to the dislodgement of Boulder 1 from the South Massif and emplacement in its present position

Metamorphosis of the coal sector. From dirty to clean?; Metamorfose van de kolensector. Van vies naar schoon?

Energy Technology Data Exchange (ETDEWEB)

Van den Heuvel, S.

2008-05-15

The author surveys the extreme make-over of the coal industry: from dirty to clean. To many of us, coal might seem the energy source of the past. In many countries of Western Europe, coal mines were closed decades ago and in most cases gas has replaced coal for heating. However, the worldwide use of coal has never been as high as it is today and coal consumption is expected to increase by 70% until 2030. This increase has mainly to do with the rapid growth of energy consumption in China and India. There are, however, environmental problems related to coal, the most prominent being the very high CO2 emissions, causing climate change. Capturing CO2 and burying it in geological formation underground, a technology called Carbon Capture and Storage (CCS), could potentially alleviate the CO2 burden that is inevitably related to coal. However, CCS is not yet a proven method and there are many uncertainties to be taken away. This leaves a gap between the international and European policy goals of decreasing global CO2 emissions and the emissions caused by coal. In fact, it shows the necessity of reaching an international climate agreement (post Kyoto) and of creating a fair efforts sharing balance between the industrialized and developing countries. [Dutch] De auteur geeft een overzicht van de extreme veranderingen in de steenkoolindustrie om deze schoner te laten produceren. Voor velen van ons lijken kolen misschien de energiebron van het verleden. In veel landen van West-Europa, werden kolenmijnen tientallen jaren geleden gesloten en in de meeste gevallen heeft aardgas steenkool vervangen voor verwarming. Echter, het wereldwijde gebruik van steenkool is nog nooit zo hoog geweest als nu en het verbruik van steenkool zal naar verwachting met 70% stijgen tot 2030. Deze stijging heeft vooral te maken met de snelle groei van het energieverbruik in China en India. Er zijn echter milieuproblemen in verband met steenkool, waarvan de meest prominente de zeer hoge CO2-uitstoot

Filosofiese tendense in die wordinggeskiedenis van ons verstaan van die fisiese natuur

Directory of Open Access Journals (Sweden)

D. F. M. Strauss

2006-09-01

Full Text Available Die ontstaan van ’n lang tradisie van natuurwetenskaplike denke is in antieke Griekeland te vind – die bakermat van die Westerse beskawing en die bron van geartikuleerde rasionele besinning. Die vroegste fases van die Griekse kultuur het reeds geboorte geskenk aan ’n teoretiese nadenke oor die heelal. Die Pythagoreërs is veral bekend vir hul klem op die verklaringskrag van getalsverhoudinge. In hul tese dat “alles getal is” het hulle egter slegs rasionale getalle (breuke erken en gevolglik uiteindelik vasgeloop in die ontdekking van irrasionale getalle wat tot die geometrisering van die Griekse wiskunde gelei het en tegelyk die bedding gevorm het van waaruit ’n magtige tradisie van ruimte-metafisika gegroei het wat die hele middeleeuse tydperk omspan het. Die vermeende statiese syn is in die mees ekstreme geval – die skool van Parmenides en die argumente van Zeno teen veelheid en beweging – tot in die uiteindelike antinomiese konsekwensies daarvan deurdink. Dit was egter eers die vroeg-moderne tyd – die voorgangers en nakomelinge van Galilei – wat naas getal en ruimte ’n waardering ontwikkel het vir die verklaringskrag van beweging (vergelyk die klassieke meganistiese wêreldbeeld van die heelal as ’n meganisme van stofdeeltjies in beweging. Maar ook hierdie meganistiese reduksie (waardeur alle fisiese verskynsels herlei is tot die beweging van al of niegelade massapunte sou uiteindelik misluk omdat dit nie van die onomkeerbaarheid van fisiese prosesse rekenskap kon gee nie. Gevolglik beliggaam eers die fisika van die 20ste eeu ’n erkenning van die deurslaggewend-stempelende rol van energie-werking (dus van die fisiese aspek in die aard van stoflike dinge en prosesse. Die artikel word afgesluit met ’n vlugtige verduideliking van die implikasies van die voorafgaande argumentasie vir ’n benadering van die misterie van die bestaan van materie.

Scattering of neutral metal clusters: Long-range interactions and response properties

International Nuclear Information System (INIS)

Kresin, V.V.; Scheidemann, A.

1993-01-01

The absolute integral cross sections for low-energy collisions of neutral sodium clusters Na n (n=2--40) with atoms and molecules (Ar, N 2 , O 2 , and halogens) have been measured. The cross sections are found to be exceptionally large (up to thousands of square angstroms), showing the dominant role of long-range intermolecular interactions. Elastic scattering proceeding under the influence of the van der Waals force, and a reaction channel involving electron transfer can successfully describe the measurements. The strength of the van der Waals potential is defined by such cluster response properties as the electric polarizability and the frequency of the giant dipole resonance. The reactive electron-jump channel, in turn, is described by the ''harpooning'' mechanism which is sensitive to the cluster ionization potential. Employing parameters taken from spectroscopic studies of alkali clusters, we obtain good agreement with the observed cross sections. This provides a direct connection between beam scattering experiments and studies of cluster electromagnetic response properties

Beoordeling van het gedrag van bestrijdingsmiddelen in de verzadigde zone van de bodem

NARCIS (Netherlands)

Linden AMA van der; Beek CGEM van; Boesten JJTI; Leistra M; Meinardi CR; Puijker LM; LBG

1994-01-01

In het MeerJarenPlan-Gewasbescherming van 1991 is de mogelijkheid gegeven om door middel van onderzoek in de verzadigde fase van de bodem aan te tonen dat bestrijdingsmiddelen, die kunnen uitspoelen naar de verzadigde zone, alsnog voor toelating in aanmerking kunnen komen als de

Penning ionization cross sections of excited rare gas atoms

International Nuclear Information System (INIS)

Ukai, Masatoshi; Hatano, Yoshihiko.

1988-01-01

Electronic energy transfer processes involving excited rare gas atoms play one of the most important roles in ionized gas phenomena. Penning ionization is one of the well known electronic energy transfer processes and has been studied extensively both experimentally and theoretically. The present paper reports the deexcitation (Penning ionization) cross sections of metastable state helium He(2 3 S) and radiative He(2 1 P) atoms in collision with atoms and molecules, which have recently been obtained by the authors' group by using a pulse radiolysis method. Investigation is made of the selected deexcitation cross sections of He(2 3 S) by atoms and molecules in the thermal collisional energy region. Results indicate that the cross sections are strongly dependent on the target molecule. The deexcitation probability of He(2 3 S) per collision increases with the excess electronic energy of He(2 3 S) above the ionization potential of the target atom or molecule. Another investigation, made on the deexcitation of He(2 1 P), suggests that the deexcitation cross section for He(2 1 P) by Ar is determined mainly by the Penning ionization cross section due to a dipole-dipole interaction. Penning ionization due to the dipole-dipole interaction is also important for deexcitation of He(2 1 P) by the target molecules examined. (N.K.)

Onderzoek naar de effecten van snoezelen op het gedrag van demente verpleeghuisbewoners en de werkbeleving van verzorgenden.

NARCIS (Netherlands)

Weert, J. van; Peter, J.; Dulmen, S. van; Ribbe, M.; Bensing, J.

2004-01-01

Het effect van snoezelen in de 24-uurszorg op de stemming en het gedrag van demente ouderen is nooit eerder onderzocht. Ook is in geen van de eerdere studies het effect onderzocht van snoezelen op de werkbeleving van verzorgenden. Uit onderzoek is bekend dat in verpleeghuizen waar geen

Van der Waals and Molecular Science

International Nuclear Information System (INIS)

Kox, A J

1997-01-01

For many years it has been a source of amazement to scientists and historians of science that no serious scientific biography of J D van der Waals existed. When, more than ten years ago, I became engaged in a correspondence with the Russian historian of science B E Yavelow on the topic of van der Waals, whose biography he was writing, I was both pleased and a bit puzzled. It was clear that Yavelow had not done any archival research in the Netherlands himself, yet he was intimately familiar with many obscure facts from the life of van der Waals. Naturally, I was very curious to see the end result, which appeared in 1985, but although the Amsterdam University Library obtained a copy, my limited knowledge of Russian kept me from forming a judgement on the book. Finally, after more than ten years, an English edition has appeared. The two original Russian authors have joined forces with the well known scientist J S Rowlinson (who earlier edited an English translation of van der Waals's dissertation) to produce a revised and enlarged English version of the Russian original. Now that I have finally been able to study this work, I must admit to being much impressed. Both the life and the work of van der Waals are dealt with in an exemplary way: the authors' command of primary and secondary sources is impressive, as is their understanding of the Dutch social and educational circumstances in the last century. Teaching and research at the newly-founded University of Amsterdam, as well as activities in the Academy of Sciences, are discussed in great and interesting detail. Van der Waals's education and rise from a simple teacher to one of the foremost theoretical physicists in Europe teaches us much about his personality as well as about the opportunities offered by the Dutch educational system. In their discussion of the development of van der Waals's ideas and their impact (including an interesting chapter on the reception in Russia) the authors are not afraid to go into

Beoordeling van het gedrag van bestrijdingsmiddelen in de verzadigde zone van de bodem

NARCIS (Netherlands)

Linden, van der A.M.A.; Beek, van C.G.E.M.; Boesten, J.J.T.I.; Leistra, M.; Meinardi, C.R.; Puijker, L.M.

1999-01-01

In het MeerJarenPlan-Gewasbescherming van 1991 is de mogelijkheid gegeven om door middel van onderzoek in de verzadigde fase van de bodem aan te tonen dat bestrijdingsmiddelen, die kunnen uitspoelen naar de verzadigde zone, alsnog voor toelating in aanmerking kunnen komen als de omzettingssnelheid

Novel phenomena in clusters irradiated by short-wavelength free-electron lasers

International Nuclear Information System (INIS)

Fukuzawa, Hironobu; Ueda, Kiyoshi

2017-01-01

By electron spectroscopy, we investigated various phenomena that are caused by the irradiation of extreme ultraviolet (EUV) and X-ray free-electron laser (FEL) pulses on rare-gas clusters. The results for the Ne clusters, which were irradiated by EUVFEL pulses at a photon energy of 20.3 eV below the ionization threshold, illustrate that novel interatomic processes yield low-energy electrons. The results for the Xe clusters, irradiated by EUVFEL pulses at a photon energy of 24.3 eV above the threshold, illustrate that nanoplasma is formed as a result of trapping the photoelectrons and consequently emits low-energy thermal electrons. The results for the Ar clusters irradiated by 5 keV XFEL pulses illustrate that nanoplasma is formed by trapping low-energy Auger electrons and secondary electrons in the tens of fs range, and continuous thermal emission from the plasma occurs in the ps range. (author)

INTEGRAL-FIELD STELLAR AND IONIZED GAS KINEMATICS OF PECULIAR VIRGO CLUSTER SPIRAL GALAXIES

International Nuclear Information System (INIS)

Cortés, Juan R.; Hardy, Eduardo; Kenney, Jeffrey D. P.

2015-01-01

We present the stellar and ionized gas kinematics of 13 bright peculiar Virgo cluster galaxies observed with the DensePak Integral Field Unit at the WIYN 3.5 m telescope in order to look for kinematic evidence that these galaxies have experienced gravitational interactions or gas stripping. Two-dimensional maps of the stellar velocity V, stellar velocity dispersion σ, and the ionized gas velocity (Hβ and/or [O III]) are presented for the galaxies in the sample. The stellar rotation curves and velocity dispersion profiles are determined for 13 galaxies, and the ionized gas rotation curves are determined for 6 galaxies. Misalignments between the optical and kinematical major axes are found in several galaxies. While in some cases this is due to a bar, in other cases it seems to be associated with gravitational interaction or ongoing ram pressure stripping. Non-circular gas motions are found in nine galaxies, with various causes including bars, nuclear outflows, or gravitational disturbances. Several galaxies have signatures of kinematically distinct stellar components, which are likely signatures of accretion or mergers. For all of our galaxies, we compute the angular momentum parameter λ R . An evaluation of the galaxies in the λ R ellipticity plane shows that all but two of the galaxies have significant support from random stellar motions, and have likely experienced gravitational interactions. This includes some galaxies with very small bulges and truncated/compact Hα morphologies, indicating that such galaxies cannot be fully explained by simple ram pressure stripping, but must have had significant gravitational encounters. Most of the sample galaxies show evidence for ICM-ISM stripping as well as gravitational interactions, indicating that the evolution of a significant fraction of cluster galaxies is likely strongly impacted by both effects

Bepaling van de optredende temperaturen bij tunnelcompostering van geitenmest

NARCIS (Netherlands)

Melse, R.W.; Sauvage, de G.J.; Roest, H.I.J.

2010-01-01

Het doel van het project is om inzicht te krijgen in de composteerbaarheid van geitenmest en het hiermee samenhangende temperatuursverloop . Bepaald dient te worden welke temperaturen tijdens het composteren van geitenmest worden bereikt om op basis daarvan een inschatting te kunnen maken van de

Kleinschalige raffinage van bietenblad : eerste verkenning van de moglijkheden

NARCIS (Netherlands)

Wolf, de P.L.; Visser, de C.L.M.; Keijsers, E.R.P.; Meesters, K.P.H.; Heesakkers, J.W.M.; Aerts, M.

2013-01-01

Doelstelling van de eerste fase van het onderzoek was ‘het verkennen van kleinschalige keten(s) voor de raffinage van bietenblad’, met aandacht voor de technologische en economische haalbaarheid. Deze verkenning vormt de basis voor de volgende fase, waarin kansrijke opties verder worden uitgewerkt

An Experimental Observation of Axial Variation of Average Size of Methane Clusters in a Gas Jet

International Nuclear Information System (INIS)

Ji-Feng, Han; Chao-Wen, Yang; Jing-Wei, Miao; Jian-Feng, Lu; Meng, Liu; Xiao-Bing, Luo; Mian-Gong, Shi

2010-01-01

Axial variation of average size of methane clusters in a gas jet produced by supersonic expansion of methane through a cylindrical nozzle of 0.8 mm in diameter is observed using a Rayleigh scattering method. The scattered light intensity exhibits a power scaling on the backing pressure ranging from 16 to 50 bar, and the power is strongly Z dependent varying from 8.4 (Z = 3 mm) to 5.4 (Z = 11 mm), which is much larger than that of the argon cluster. The scattered light intensity versus axial position shows that the position of 5 mm has the maximum signal intensity. The estimation of the average cluster size on axial position Z indicates that the cluster growth process goes forward until the maximum average cluster size is reached at Z = 9 mm, and the average cluster size will decrease gradually for Z > 9 mm

Sustainable protein from biogas. The perspective of susteine; Duurzaam eiwit uit biogas. Verkenning van het perspectief van susteine

Energy Technology Data Exchange (ETDEWEB)

Oosterhuis, N. [Easthouse Business Solutions, Rolde (Netherlands); Hooijer, H. [We-Do Interim Management and Consultancy, Culemborg (Netherlands)

2007-12-15

aanvullend onderzoekstraject vraagt. Binnen de Europese markt behoeft een afzet van 10.000 ton/jaar geen probleem te vormen. De meest hoogwaardige toepassing is in biggenvoeders. Technisch is productie van Susteine op basis van biogas in principe mogelijk. Voorwaarde is wel dat het methaan uit biogas zodanig wordt gezuiverd dat het voldoet als grondstof voor eiwitproductie. Hiervoor zijn technologieen beschikbaar. De kwaliteitseisen aan de grondstof zouden moeten worden vastgelegd; hier is uiteraard nader onderzoek voor nodig. Een belangrijk knelpunt voor de financieel-economische haalbaarheid is de schaalgrootte van de biogasinstallatie. Voor productie van 10.000 t eiwit/jaar is globaal 30-35 miljoen m{sup 3} biogas nodig, oftewel 2 miljoen ton mest. Dit leidt tot een ongewenst aantal transportbewegingen, ook mede gezien het feit dat een vergelijkbare hoeveelheid digestaat (rest van de biogasproductie) moet worden afgevoerd. Een unieke kans in Nederland is het gebruik van het aardgasnet voor het 'transport' van het (bio)gas. Hierdoor zou de mestvergisting lokaal kunnen gebeuren, terwijl de eiwitproductie centraal kan plaatsvinden. Deze oplossing is echter vooralsnog niet toegelaten. Een aanbeveling is om deze optie nader te onderzoeken. Een tweede knelpunt in de financieel-economische haalbaarheid vormt de afzet van digestaat. Dit is een algemeen probleem bij de mestvergisting. In omringende landen wordt gewerkt aan het drogen van digestaat, en toepassing als brandstof. De vrijkomende mineralenstroom kan worden ingezet als kunstmestvervanging. Ook dit zal onderhevig zijn aan wet- en regelgeving (Minas), hetgeen de invoering bemoeilijkt. Als alternatief kan worden gedacht aan het isoleren van de mineralen uit digestaat en het zover zuiveren van deze stroom dat lozing mogelijk wordt. De kosten van een dergelijk proces zullen aanzienlijk zijn, maar de mineralen kunnen tegelijkertijd een toegevoegde waarde opleveren. In zijn algemeenheid kan worden gesteld dat eerder

Measurements of the gas temperature and iron abundance distribution in the Coma Cluster

International Nuclear Information System (INIS)

Hughes, J.P.; Gorenstein, P.; Fabricant, D.

1988-01-01

The medium energy X-ray detectors onboard the EXOSAT Observatory have been used to determine the gas temperature at several positions in the Coma Cluster of galaxies. Evidence is found at greater than 95 percent confidence for a higher temperature in the center of the cluster than in a position approximately 45 arcmin off-center. No difference in iron abundance is observed between the center and off-center regions and the equilibrium model for the distribution of elements in the Coma Cluster of Abramopoulos, Chanan, and Ku can be rejected with greater than 99.5 percent confidence, in favor of a model with more uniform composition. A phenomenological model is presented of the Coma Cluster, which is consistent with the data presented here, as well as the imaging data from the Einstein Observatory and the Tenma X-ray spectrum. The model has a central isothermal region of temperature about 9 keV extending to about 25 arcmin (about 1 Mpc). Beyond this radius the temperature falls as a polytrope with index about 1.6. 36 references

Ellis van creveld syndrome with unusual association of essential infantile esotropia

Directory of Open Access Journals (Sweden)

D Das

2010-01-01

Full Text Available Ellis-van Creveld syndrome is a rare short-limbed disproportionate dwarfism characterized by postaxial polydactyly, several skeletal, oral mucosal and dental anomalies, nail dysplasia and in 50-60% cases of congenital cardiac defects. It is an autosomal recessive disorder with mutations of the EVC1 and EVC2 genes located on chromosome 4p16. Patients with this syndrome usually have a high mortality in early life due to cardiorespiratory problems. We present the case of a six- month-old female infant with Ellis-van Creveld syndrome - essential infantile esotropia, which has been infrequently documented in the literature.

Dynamics of exciplex formation in rare gas media

Energy Technology Data Exchange (ETDEWEB)

Rojas-Lorenzo, German, E-mail: grojas37@gmail.com [Departamento de Fisica General y Matematicas, Instituto Superior de Tecnologias y Ciencias Aplicadas, La Habana (Cuba)] [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid (Spain); Rubayo-Soneira, Jesus [Departamento de Fisica General y Matematicas, Instituto Superior de Tecnologias y Ciencias Aplicadas, La Habana (Cuba); Alberti, Sebastian Fernandez [Centro de Estudios e Investigaciones, Universidad Nacional de Quilmes, Roque Saenz Pena 180, Bernal B1876BXD (Argentina)

2009-07-30

A hopping-surface algorithm has been used to simulate the dynamics induced in rare gas matrices due to the photoexcitation ({sup 1}S{sub 0} {yields} {sup 3}P{sub 1}) of atomic mercury embedded in them. Especially, the study of the dynamics of an exciplex formation in a model system consisting of solid xenon doped with atomic mercury. The process starts upon the photoexcitation of the Hg atom to its {sup 3}P{sub 1} electronic excited state. Diatomics-in-Molecule approach has been used for constructing the adiabatic potential surfaces. In all trajectories we show that a triatomic Xe-Hg{sup *}-Xe complex is formed, but in two conformations: bent and linear. The mechanisms leading to the formation of one or the other are identified. Mainly, are noted the thermal fluctuations of the Hg impurity and the shape of the potential surfaces. Furthermore, we show that non-radiative intrastate relaxation occurs via a conical intersection between the excited state surfaces. The simulated spectra are in very good agreement with the experimental data.

Die gebruik van parallelplaatreologie vir die bepaling van die intrinsieke viskositeit van poli-etileentereftalaat

Directory of Open Access Journals (Sweden)

O. C. Vorster

2005-09-01

Full Text Available Die bepaling van die intrinsieke viskositeit van poli-etileentereftalaat word bemoeilik deur die feit dat daar tans slegs twee metodes in gebruik is. In die eerste metode word die bepaling deur middel van oplossingsviskometrie gedoen, maar die toksisiteit van die oplosmiddel, asook die tydperk wat dit neem om die bepaling te doen, is ’n probleem. Die tweede metode word beperk deur die kompleksiteit en beskikbaarheid van die apparatuur in Suid-Afrika. In hierdie studie word ’n alternatiewe metode, gebaseer op parallelplaatreologie, voorgestel wat albei hierdie probleme oorkom en die resultate sodoende verkry, word vergelyk met dié wat met bestaande metodes verkry is.

Chondroectodermal dysplasia: a rare syndrome.

Directory of Open Access Journals (Sweden)

Dana Tahririan

2014-06-01

Full Text Available Chondroectodermal dysplasia (Ellis-Van Creveld syndrome is a rare autosomal recessive congenital abnormality. This syndrome is characterized by a spectrum of clinical findings, among which chondrodystrophy, polydactyly, ectodermal dysplasia, and congenital cardiac anomalies are the most common. It is imperative to not overlook the cardiac complications in patients with this syndrome during dental procedures. The case presented here, although quite rare, was detected under normal conditions and can be alarming for dental care providers. Clinical reports outline the classical and unusual oral and dental manifestations, which help health care providers diagnose chondroectodermal dysplasia, and refer patients with this syndrome to appropriate health care professionals to receive treatment to prevent further cardiac complications and bone deformities.

NATO Advanced Research Workshop on Dynamics of Polyatomic Van der Waals Complexes

CERN Document Server

Janda, Kenneth

1991-01-01

This publication is the Proceedings of the NATO Advanced Research Workshop (ARW) on the Dynamics of Polyatomic Van der Waals Molecules held at the Chateau de Bonas, Castera-Verduzan, France, from August 21 through August 26, 1989. Van der Waals complexes provide important model problems for understanding energy transfer and dissipation. These processes can be described in great detail for Van der Waals complexes, and the insight gained from such studies can be applied to more complicated chemical problems that are not amenable to detailed study. The workshop concentrated on the current questions and future prospects for extend­ ing our highly detailed knowledge of triatomic Van der Waals molecule dynamics to polyatomic molecules and clusters (one molecule surrounded by several, or up to sev­ eral tens of, atoms). Both experimental and theoretical studies were discussed, with particular emphasis on the dynamical behavior of dissociation as observed in the dis­ tributions of quantum states of the dissociatio...

Formation of the First Star Clusters and Massive Star Binaries by Fragmentation of Filamentary Primordial Gas Clouds

Science.gov (United States)

Hirano, Shingo; Yoshida, Naoki; Sakurai, Yuya; Fujii, Michiko S.

2018-03-01

We perform a set of cosmological simulations of early structure formation incorporating baryonic streaming motions. We present a case where a significantly elongated gas cloud with ∼104 solar mass (M ⊙) is formed in a pre-galactic (∼107 M ⊙) dark halo. The gas streaming into the halo compresses and heats the massive filamentary cloud to a temperature of ∼10,000 Kelvin. The gas cloud cools rapidly by atomic hydrogen cooling, and then by molecular hydrogen cooling down to ∼400 Kelvin. The rapid decrease of the temperature and hence of the Jeans mass triggers fragmentation of the filament to yield multiple gas clumps with a few hundred solar masses. We estimate the mass of the primordial star formed in each fragment by adopting an analytic model based on a large set of radiation hydrodynamics simulations of protostellar evolution. The resulting stellar masses are in the range of ∼50–120 M ⊙. The massive stars gravitationally attract each other and form a compact star cluster. We follow the dynamics of the star cluster using a hybrid N-body simulation. We show that massive star binaries are formed in a few million years through multi-body interactions at the cluster center. The eventual formation of the remnant black holes will leave a massive black hole binary, which can be a progenitor of strong gravitational wave sources similar to those recently detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO).

Die identifisering van maatstawwe vir die navorsingsprestasie van akademici

Directory of Open Access Journals (Sweden)

H. A. Labuschagne

1990-06-01

Full Text Available Identification of criteria for academic research performance. At South African universities, the achievement of objectives is usually measured in terms of so-called "process criteria" (e.g. pass rates, instead of performance criteria which reflect the quality of academic personnel. Stimulated by the need to identify valid indices of research performance, as a component of academic performance, this study investigated the dimensionality of several criteria, identified from empirical and literature studies. It was found that various valid criteria could be represented by six constructs, viz.: the stature of the researcher as scientist; scientific contributions; enhancement of own profession; community development; participation in research projects; and giving advice to persons or institutions outside the university. Opsomming By Suid-Afrikaanse universiteite word doelwitbereiking gewoonlik aan die hand van sogenaamde "prosesmaat-stawwe" (bv. slaagsyfers in plaas van prestasiemaatstawwe wat die gehalte van akademiese personeel weerspieel, gemeet. Na aanleiding van 'n behoefte aan die identifisering van geldige rigtingwysers vir navorsingsprestasie as 'n komponent van akademiese prestasie, is daar ondersoek ingestel na die dimensionaliteit van verskillende maatstawwe wat vooraf deur middel van empiriese- en literatuurstudies geidentifiseer is. Daar is gevind dat verskeie geldige maatstawwe deur ses konstrukte verteenwoordig word, te wete: die statuur van die navorser as wetenskaplike, wetenskaplike bydraes, uitbouing van eie professie, gemeenskapsontwikkeling, deelname aan navorsingsprojekte en advieslewering aan persone of instellings buite die Universiteit.

Effects of the liquid-gas phase transition and cluster formation on the symmetry energy

International Nuclear Information System (INIS)

Typel, S.; Wolter, H.H.; Roepke, G.; Blaschke, D.

2014-01-01

Various definitions of the symmetry energy are introduced for nuclei, dilute nuclear matter below saturation density and stellar matter, which is found in compact stars or core-collapse supernovae. The resulting differences are exemplified by calculations in a theoretical approach based on a generalized relativistic density functional for dense matter. It contains nucleonic clusters as explicit degrees of freedom with medium-dependent properties that are derived for light clusters from a quantum statistical approach. With such a model the dissolution of clusters at high densities can be described. The effects of the liquid-gas phase transition in nuclear matter and of cluster formation in stellar matter on the density dependence of the symmetry energy are studied for different temperatures. It is observed that correlations and the formation of inhomogeneous matter at low densities and temperatures causes an increase of the symmetry energy as compared to calculations assuming a uniform uncorrelated spatial distribution of constituent baryons and leptons. (orig.)

Experimental study of the dissociation of 100-600 KeV hydrogen cluster ions in an argon gas target

International Nuclear Information System (INIS)

Chevallier, M.; Clouvas, A.; Frischkorn, H.J.; Gaillard, M.J.; Poizat, J.C.; Remillieux, J.

1985-09-01

We have studied the break-up of accelerated hydrogen cluster ions passing through an argon gas target. The absolute dissociation cross section has been measured for a wide variety of H n + (odd masses only) cluster ions, with n between 5 and 23 and with projectile velocities ranging from 1.5 to 5 x 10 8 cm/s. We discuss the dissociation processes and the dependence of their cross-sections upon the cluster mass and velocity

Invloed van minerale olie op de bestrijding van Phytophthora infestans in pootaardappelen

NARCIS (Netherlands)

Spits, H.G.; Bus, C.B.

2003-01-01

De invloed van toevoeging van olie aan een fungicide op de werking van het fungicide is afhankelijk van het gebruikte fungicide. Gezamenlijk spuiten van olie en Aviso DF, Curzate M en mogelijk ook Acrobat, verhoogt de curatieve werking van deze fungiciden. Gezamenlijk spuiten van olie en Aviso DF,

Formation of a Boundary-Free Dust Cluster in a Low-Pressure Gas-Discharge Plasma

International Nuclear Information System (INIS)

Usachev, A. D.; Zobnin, A. V.; Petrov, O. F.; Fortov, V. E.; Annaratone, B. M.; Thoma, M. H.; Hoefner, H.; Kretschmer, M.; Fink, M.; Morfill, G. E.

2009-01-01

An attraction between negatively charged micron-sized plastic particles was observed in the bulk of a low-pressure gas-discharge plasma under microgravity conditions. This attraction had led to the formation of a boundary-free dust cluster, containing one big central particle with a radius of about 6 μm and about 30 1 μm-sized particles situated on a sphere with a radius of 190 μm and with the big particle in the center. The stability of this boundary-free dust cluster was possible due to its confinement by the plasma flux on the central dust particle

Cluster finds giant gas vortices at the edge of Earth's magnetic bubble

Science.gov (United States)

2004-08-01

12 August 2004 ESA’s quartet of space-weather watchers, Cluster, has discovered vortices of ejected solar material high above the Earth. The superheated gases trapped in these structures are probably tunnelling their way into the Earth’s magnetic ‘bubble’, the magnetosphere. This discovery possibly solves a 17-year-mystery of how the magnetosphere is constantly topped up with electrified gases when it should be acting as a barrier. hi-res Size hi-res: 1446 Kb Credits: H. Hasegawa (Dartmouth College) Three-dimensional cut-away view of Earth's magnetosphere This figure shows a three-dimensional cut-away view of Earth' s magnetosphere. The curly features sketched on the boundary layer are the Kelvin-Helmholtz vortices discovered by Cluster. They originate where two adjacent flows travel with different speed. In this case, one of the flows is the heated gas inside the boundary layer of the magnetosphere, the other the solar wind just outside it. The arrows show the direction of the magnetic field, in red that associated with the solar wind and in green the one inside Earth’s magnetosphere. The white dashed arrow shows the trajectory followed by Cluster. High resolution version (JPG format) 1446 Kb High resolution version (TIFF format) 15 365 Kb hi-res Size hi-res: 22 Kb Credits: H. Hasegawa (Dartmouth College) Electrified gas varies across the vortices along Cluster’s trajectory This computer simulation shows how the density of the electrified gas is expected to vary across the vortices along Cluster’s trajectory (white dashed line). The density is lower inside the boundary layer (blue region) and higher outside, in the region dominated by the solar wind (shown in red). The density variations measured by the instruments on board Cluster match those predicted by this model. Low resolution version (JPG format) 22 Kb High resolution version (TIFF format) 3438 Kb The Earth’s magnetic field is our planet’s first line of defence against the bombardment of

B. J. van der Merwe . Pentateugtradisies in die prediking van ...

African Journals Online (AJOL)

B. J. van der Merwe . Pentateugtradisies in die prediking van Deuterojesaja. Proefschrift ter verkrijging van de graad van Doctor in de Godgeleerdheid aan de Rijkuniversiteit te Groningen. Uitg. J. B. Wolters, Groningen, Djakarta. 1955. 280 bls.

n Oorsig van die huidige stand van navorsing oor die

African Journals Online (AJOL)

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7 Jun 2011 ... Die eerste maal wat dit as deel van die teks van 1 Johannes aangehaal word, is in die. 4de eeu in 'n Latynse teks, Liber Apologeticus (hf 4). Eers aan die einde van die 16de eeu is dit in 'n amptelike Katolieke uitgawe van die Vulgaat ingesluit. Die doel van die Johannesbriewe. Waarom is die Briewe ...

Brome isotope selective control of CF3Br molecule clustering by IR laser radiation in gas-dynamic expansion of CF3Br - Ar mixture

Science.gov (United States)

Apatin, V. M.; Lokhman, V. N.; Makarov, G. N.; Ogurok, N.-D. D.; Ryabov, E. A.

2018-02-01

We report the results of research on the experimental control of CF3Br molecule clustering under gas-dynamic expansion of the CF3Br - Ar mixture at a nozzle exit by using IR laser radiation. A cw CO2 laser is used for exciting molecules and clusters in the beam and a time-of-flight mass-spectrometer with laser UV ionisation of particles for their detection. The parameters of the gas above the nozzle are determined (compositions and pressure) at which intensive molecule clustering occurs. It is found that in the case of the CF3Br gas without carrier when the pressure P0 above the nozzle does not exceed 4 atm, molecular clusters actually are not generated in the beam. If the gas mixture of CF3Br with argon is used at a pressure ratio 1 : N, where N >= 3, and the total pressure above the nozzle is P0 >= 2 atm, then there occurs molecule clustering. We study the dependences of the efficiency of suppressing the molecule clustering on parameters of the exciting pulse, gas parameters above the nozzle, and on a distance of the molecule irradiation zone from the nozzle exit section. It is shown that in the case of resonant vibrational excitation of gas-dynamically cooled CF3Br molecules at the nozzle exit one can realise isotope-selective suppression of molecule clustering with respect to bromine isotopes. With the CF3Br - Ar mixtures having the pressure ratio 1 : 3 and 1 : 15, the enrichment factors obtained with respect to bromine isotopes are kenr ≈ 1.05 ± 0.005 and kenr ≈ 1.06 ± 0.007, respectively, under jet irradiation by laser emission in the 9R(30) line (1084.635 cm-1). The results obtained let us assume that this method can be used to control clustering of molecules comprising heavy element isotopes, which have a small isotopic shift in IR absorption spectra.

Propagation of lower-band whistler-mode waves in the outer Van Allen belt: Systematic analysis of 11 years of multi-component data from the Cluster spacecraft

Czech Academy of Sciences Publication Activity Database

Santolík, Ondřej; Macúšová, Eva; Kolmašová, Ivana; Cornilleau-Wehrlin, N.; De Conchy, Y.

2014-01-01

Roč. 41, č. 8 (2014), s. 2729-2737 ISSN 0094-8276 R&D Projects: GA MŠk 7E12026; GA ČR GAP205/10/2279 Institutional support: RVO:68378289 Keywords : whistler-mode chorus * wave vector directions * Van Allen radiation belts Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 4.456, year: 2013 http://onlinelibrary.wiley.com/doi/10.1002/2014GL059815/abstract

Detectie van Meloidogyne spp. in grondmonsters - een vergelijking van twee technieken

NARCIS (Netherlands)

Veenhuizen, P.T.M.; Schoemakers, N.; Vos, J.; Versteegen, F.; Landeweert, R.; Karssen, G.

2007-01-01

Hier volgen de samenvattingen van de bijeenkomst van 20 maart 2007 van de KNPV-werkgroep Meloidogyne. 1) Kwantitatieve multiplexdetectie van aaltjes; 2). Meloidogyne chitwoodi en M. fallax: vergelijking visuele beoordeling en Taqman-PCR aan pootaardappelen; 3) Detectie van Meloidogyne spp. in

Van der Waals equation of state revisited: importance of the dispersion correction.

Science.gov (United States)

de Visser, Sam P

2011-04-28

One of the most basic equations of state describing nonideal gases and liquids is the van der Waals equation of state, and as a consequence, it is generally taught in most first year undergraduate chemistry courses. In this work, we show that the constants a and b in the van der Waals equation of state are linearly proportional to the polarizability volume of the molecules in a gas or liquid. Using this information, a new thermodynamic one-parameter equation of state is derived that contains experimentally measurable variables and physics constants only. This is the first equation of state apart from the Ideal Gas Law that contains experimentally measurable variables and physics constants only, and as such, it may be a very useful and practical equation for the description of dilute gases and liquids. The modified van der Waals equation of state describes pV as the sum of repulsive and attractive intermolecular interaction energies that are represented by an exponential repulsion function between the electron clouds of the molecules and a London dispersion component, respectively. The newly derived equation of state is tested against experimental data for several gas and liquid examples, and the agreement is satisfactory. The description of the equation of state as a one-parameter function also has implications on other thermodynamic functions, such as critical parameters, virial coefficients, and isothermal compressibilities. Using our modified van der Waals equation of state, we show that all of these properties are a function of the molecular polarizability volume. Correlations of experimental data confirm the derived proportionalities.

Bestuurlijke turbulentie in het sociaal werk: de uitdaging van meervoudige coalitievorming

Directory of Open Access Journals (Sweden)

Marc Hoijtink

2011-08-01

Net als elders in Europa wordt het sociaal werk in Nederland geconfronteerd met indringende bestuurlijke veranderingen. In dit artikel analyseren wij met welke bestuurlijke veranderingen instellingen in het lokaal sociaal werk te maken hebben en hoe representanten van deze instellingen op deze veranderingen reageren. Het artikel bestaat uit drie delen. In het eerste deel beschrijven we vier in het oog springende bestuurlijke veranderingen waarmee organisaties in dit veld geconfronteerd worden. In het tweede deel analyseren we op basis van verschillende onderzoeken in het lokaal sociaal werk hoe representanten van deze organisaties – sociaal werkers en managers – deze veranderingen ervaren en hoe zij hiermee omgaan. We onderscheiden vier clusters reacties: de verwarde reactie, de introverte reactie, de extraverte reactie en de verbindende reactie. In het derde deel zoomen we in op de ons inziens meest vruchtbare reactiewijze: de verbindende reactie. We betogen dat deze turbulente tijd vraagt om organisaties die erin slagen om zowel sterke interne als krachtige externe coalities te creëren, nodig om de kwaliteit van de dienstverlening te waarborgen en betekenisvol te innoveren.

Stroming en samenstelling van de sprengen en het grondwater van de Veluwe in 1996; een vergelijking met de toestand van 1986

NARCIS (Netherlands)

Meinardi CR; LBG

1999-01-01

Monsters water uit sprengen en grondwater van de Veluwe zijn onderzocht op concentraties van hoofdcomponenten en van microcomponenten (bepalingen door NITG). Onderzoek is gedaan ter bepaling van verblijftijden in de bodem van grondwater en van het water in sprengen. De intrekgebieden van de

A. VAN SELMS. LUKAS SE SEGSMAN VIR DIE GESKIEDENIS VAN ...

African Journals Online (AJOL)

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oordele aan die eerste drie hoofstukke van sy Evangelie, het Lukas onder „van ..... Simon te onderskei van Simon Petrus, hoef ons nie erns te maak nie. .... op hulle beurt vereenselwig met Mosa van Jos. .... i&) Lukas der Arzt. Leipzig, 1906.

Monitoring of effects of land subsidence at Ameland-Oost, Netherlands. Evaluation after 18 years of natural gas exploration. Summary; Monitoring effecten van bodemdaling op Ameland-Oost. Evaluatie na 18 jaar gaswinning. Samenvatting

Energy Technology Data Exchange (ETDEWEB)

Eysink, W.D.; Wang, Z. [Waterloopkundig Laboratorium WL - Delft Hydraulics, Delft (Netherlands); Dijkema, K.S.; Slim, P.A.; Dankers, N.M.J.A.; Sanders, M.E.; Van Dobben, H.F. [ALTERRA, Wageningen (Netherlands); Krol, J.; Kersten, M.; Molenaar, W. [Natuurcentrum Ameland, Nes (Netherlands); Doornhof, D.; Schoustra, S.; Veldwisch, W. [Nederlandse Aardolie Maatschappij NAM, Assen (Netherlands)

2005-05-15

After the start of the natural gas exploitation on the Dutch island Ameland in 1986 surveys were carried out from 1988 on to investigate and monitor the effect of the exploitation on land subsidence and related environmental effects. In this third report evaluated results of that survey over the last 18 years are presented and discussed. [Dutch] De gaswinning op Ameland-Oost is begonnen in 1986. In dat zelfde jaar werd in opdracht van de NAM door WL|Delft Hydraulics in samenwerking met Alterra (toen RIN) een voorspelling gemaakt van de mogelijke effecten van de bodemdaling, waarna eind 1988 is begonnen met de monitoring. De eerste twee rapportages zijn gebaseerd op gegevens tot 1994 respectievelijk 1999 en beschrijven de effecten over een periode van 8 jaar respectievelijk 13 jaar na het begin van de gaswinning. Deze derde rapportage is gebaseerd op gegevens tot 2003/2004. Voor meer achtergrondinformatie wordt verwezen naar het evaluatierapport van maart 2000 en het nieuwe monitoringsprogramma 2000-2010 die op de bijgevoegde CD aanwezig zijn. De bodemdaling vond plaats in de vorm van een grote schotel met een doorsnede van ongeveer 15 km, en werd meetbaar vanaf 1987. In de periode daarna, ongeveer tot het jaar 2000, daalde de bodem in het centrum van de schotel met ongeveer 1,8 cm per jaar. Daarna begon de dalingssnelheid wat af te nemen, door de daling van de druk in het veld, tot circa 1,2 cm per jaar. In 2003 bedroeg de bodemdaling in het centrum van de bodemdalingschotel 27 cm. Verwacht wordt dat de bodemdaling steeds verder af zal nemen totdat hij rond het jaar 2020 geheel beeindigd zal zijn. In 2000 zijn de resultaten gepresenteerd in een openbaar debat. Sindsdien zijn verschillende verbeteringen doorgevoerd. De highlights van de afgelopen 5 jaar zijn de publicatie van het onderzoeksprogramma 2000-2010, het vogelonderzoek, de uitgebreide metingen op de wadplaten en de nieuw ontwikkelde techniek van spijkermetingen. Daarnaast heeft het nieuwe programma voor de

On origin of stellar clusters

International Nuclear Information System (INIS)

Tovmasyan, G.M.

1977-01-01

The ratios of the gas component of the mass of young stellar clusters to their stellar mass are considered. They change by more than four orders from one cluster to another. The results are in direct contradiction with the hypothesis of formation of cluster stars from a preliminarily existing gas cloud by its condensation, and they favour the Ambartsumian hypothesis of the joint origin of stars and gas clouds from superdense protostellar matter

Digitale incunabelen : Over het belang van het archiveren van websites

NARCIS (Netherlands)

Voerman, Gerrit; Keyzer, Andreas; den Hollander, Franciscus

'Het geheugen van Nederland verpulvert'. Zo luidde de noodkreet van ruim twintig grote bibliotheken in het voorjaar van 1998. In een advertentie in enkele landelijke dagbladen vroegen deze bibliotheken om honderden miljoenen guldens voor het restaureren, fotograferen en digitaliseren van boeken en

Digitale incunabelen : Over het belang van het archiveren van websites

NARCIS (Netherlands)

Voerman, Gerrit; Keyzer, Andreas; den Hollander, Franciscus

2000-01-01

'Het geheugen van Nederland verpulvert'. Zo luidde de noodkreet van ruim twintig grote bibliotheken in het voorjaar van 1998. In een advertentie in enkele landelijke dagbladen vroegen deze bibliotheken om honderden miljoenen guldens voor het restaureren, fotograferen en digitaliseren van boeken en

Inclusie door interprofessionele samenwerking. : Resultaten van de proeftuinen van PACT.

NARCIS (Netherlands)

Doornenbal, Jeannette; Fukkink, Ruben; van Yperen, Tom; Balledux, Mariëlle; Spoelstra, Jolanda; Verseveld, Marloes

2017-01-01

Deze rapportage gaat over de resultaten van de PACT-proeftuinen waaraan in opdracht van Het Kinderopvangfonds van 2015 tot 2017 is gewerkt. PACT-proeftuinen zijn innovatieve praktijken waarin door middel van interprofessionele samenwerking tussen de kinderopvang, het basisonderwijs en de zorg wordt

The smoke ion source: A device for the generation of cluster ions via inert gas condensation

International Nuclear Information System (INIS)

McHugh, K.M.; Sarkas, H.W.; Eaton, J.G.; Bowen, K.H.; Westgate, C.R.

1989-01-01

We report the development of an ion source for generating intense, continuous beams of both positive and negative cluster ions. This device is the result of the marriage of the inert gas condensation method with techniques for injecting electrons directly into expanding jets. In the preliminary studies described here, we have observed cluster ion size distributions ranging from n=1-400 for Pb n + and Pb n - and from n=12-5700 for Li n - . (orig.)

Gas phase reactivity of thermal metal clusters

Science.gov (United States)

Castleman, A. W., Jr.; Harms, A. C.; Leuchtner, R. E.

1991-03-01

Reaction kinetics of metal cluster ions under well defined thermal conditions were studied using a flow tube reactor in combination with laser vaporization. Aluminum anions and cations were reacted with oxygen, and several species which are predicted jellium shell closings, were found to have special stability. Metal alloy cluster anions comprised of Al, V and Nb were also seen to react with oxygen. Alloy clusters with an even number of electrons reacted more slowly than odd electron species, and certain clusters appeared to be exceptionally unreactive. Copper cation clusters were observed to associate with carbon monoxide with reactivities that approach bulk behavior at surprisingly small cluster size. These reactions demonstrate how the rate of reaction changes with cluster size.

Die opleiding van bedryfsielkundiges aan die universiteit van Fort Hare

Directory of Open Access Journals (Sweden)

W. Botha

1977-11-01

Full Text Available Die Departement Bedryfsielkunde aan die Universiteit van Fort Hare is 'n relatiewe jong departement en het eers in 1965 tot stand gekom. Voor hierdie datum is Bedryfsielkunde as 'n kort kursus deur die departement van suiwer Sielkunde aangebied en een van die destydse dosente, Dr. W. Backer, het die inisiatief geneem om 'n selfstandige departement van Bedryfsielkunde in die Fakulteit van Ekonomiese Wetenskappe op die been te bring.

Planck/SDSS Cluster Mass and Gas Scaling Relations for a Volume-Complete redMaPPer Sample

Science.gov (United States)

Jimeno, Pablo; Diego, Jose M.; Broadhurst, Tom; De Martino, I.; Lazkoz, Ruth

2018-04-01

Using Planck satellite data, we construct Sunyaev-Zel'dovich (SZ) gas pressure profiles for a large, volume-complete sample of optically selected clusters. We have defined a sample of over 8,000 redMaPPer clusters from the Sloan Digital Sky Survey (SDSS), within the volume-complete redshift region 0.100 trend towards larger break radius with increasing cluster mass. Our SZ-based masses fall ˜16% below the mass-richness relations from weak lensing, in a similar fashion as the "hydrostatic bias" related with X-ray derived masses. Finally, we derive a tight Y500-M500 relation over a wide range of cluster mass, with a power law slope equal to 1.70 ± 0.07, that agrees well with the independent slope obtained by the Planck team with an SZ-selected cluster sample, but extends to lower masses with higher precision.

Het effect van creatief schrijven op het lezen van korte verhalen

NARCIS (Netherlands)

Janssen, T.; van den Bergh, H.

2010-01-01

Schrijven en lezen zijn complementaire vaardigheden, niet alleen bij referentiële teksten, maar ook bij fictionele. Janssen en Van den Bergh doen verslag van een onderzoek naar de invloed van creatief schrijven op het lezen van verhalen. Als leerlingen, voorafgaand aan het lezen van een verhaal, een

Databank van de lithografische opbouw en morfologische ontwikkeling van de uiterwaarden van de Midden-Waal

NARCIS (Netherlands)

Hebinck, K.A.

2008-01-01

In de uiterwaarden zijn de komende decennia veel ingrepen gepland. Een goede kennis van de sedimentatiedynamiek en morfologische ontwikkeling van de uiterwaarden is daarbij een vereiste. Daartoe is een digitale databank (op CD bij dit rapport) opgesteld van de opbouw en geomorfologische ontwikkeling

Quark cluster model in the three-nucleon system

International Nuclear Information System (INIS)

Osman, A.

1986-11-01

The quark cluster model is used to investigate the structure of the three-nucleon systems. The nucleon-nucleon interaction is proposed considering the colour-nucleon clusters and incorporating the quark degrees of freedom. The quark-quark potential in the quark compound bag model agrees with the central force potentials. The confinement potential reduces the short-range repulsion. The colour van der Waals force is determined. Then, the probability of quark clusters in the three-nucleon bound state systems are numerically calculated using realistic nuclear wave functions. The results of the present calculations show that quarks cluster themselves in three-quark systems building the quark cluster model for the trinucleon system. (author)

Van der Waals potential and vibrational energy levels of the ground state radon dimer

Science.gov (United States)

Sheng, Xiaowei; Qian, Shifeng; Hu, Fengfei

2017-08-01

In the present paper, the ground state van der Waals potential of the Radon dimer is described by the Tang-Toennies potential model, which requires five essential parameters. Among them, the two dispersion coefficients C6 and C8 are estimated from the well determined dispersion coefficients C6 and C8 of Xe2. C10 is estimated by using the approximation equation that C6C10/C82 has an average value of 1.221 for all the rare gas dimers. With these estimated dispersion coefficients and the well determined well depth De and Re the Born-Mayer parameters A and b are derived. Then the vibrational energy levels of the ground state radon dimer are calculated. 40 vibrational energy levels are observed in the ground state of Rn2 dimer. The last vibrational energy level is bound by only 0.0012 cm-1.

Gas phase reactivity of thermal metal clusters

International Nuclear Information System (INIS)

Castleman, A.W. Jr.; Harms, A.C.; Leuchtner, R.E.

1991-01-01

Reaction kinetics of metal cluster ions under well defined thermal conditions were studied using a flow tube reactor in combination with laser vaporization. Aluminum anions and cations were reacted with oxygen, and several species which are predicted jellium shell closings, were found to have special stability. Metal alloy cluster anions comprised of Al, V and Nb were also seen to react with oxygen. Alloy clusters with an even number of electrons reacted more slowly than odd electron species, and certain clusters appeared to be exceptionally unreactive. Copper cation clusters were observed to associate with carbon monoxide with reactivities that approach bulk behavior at surprisingly small cluster size. These reactions demonstrate how the rate of reaction changes with cluster size. (orig.)

Evolution of rotating star clusters at the inelastic-collision stage. II. Dynamics of a disk of gas and stars

International Nuclear Information System (INIS)

Romanova, M.M.

1985-01-01

The dynamics of a gas--star disk embedded in a dense, mildly oblate (flattening epsilon-c or approx. =0.2--0.3 the stable disk will survive for at least half the cluster evolution time. The possibility of a thin disk of stars existing inside a dense star cluster is considered. For small epsilon-c and for disk member stars having > or approx. =0.04 the mass of the cluster members, collisions between cluster and disk stars will have no effect on the disk evolution prior to instability

Method for storing radioactive rare gases

International Nuclear Information System (INIS)

Watabe, Atsushi; Nagao, Hiroyuki; Takiguchi, Yukio; Kanazawa, Toshio; Soya, Masataka.

1975-01-01

Object: To safely and securely store radioactive rare gases for a long period of time. Structure: The waste gases produced in nuclear power plant are cooled by a cooler and then introduced into a low temperature adsorbing device so that the gases are adsorbed by adsorbents, and then discharged into atmosphere through the purifying gas discharge line. When the radioactive rare gases reach a level of saturation in the amount of adsorption, they are heated and extracted by a suction pump and heated by a heater. The gases are then introduced into an oxygen-impurity removing device and the purified rare gases containing no oxygen and impurities are cooled by a cooler and fed into a gas holder. When the amount of radioactive rare gases stored within the gas holder reaches a given level, they are compressed and sealed by a compressure into a storing cylinder and residual gases in the piping are sucked and recovered into the gas holder, after which the cylinder is removed and stored in a fixed room. (Kamimura, M.)

Photoemission from excited states in rare gas solids by combining synchrotronradiation with a laser

International Nuclear Information System (INIS)

Bernstorff, S.

1984-09-01

A new spectroscopic method has been developed to study excited states in rare gas solids: Excitons and conductionband-states are populated by synchrotron radiation (photon energy hw SR =5 - 30 eV). Subsequently electrons from these bound or conduction band-states are excited above the vacuum level of the solid by a pulsed dye laser (hw L =1.9 - 3.7 eV). This experimental technique was applied to solid Xe, Kr, Ar and Ne. (orig./GSCH)

Risico-evaluatie toepassing groen gas in de Nederlandse glastuinbouw

NARCIS (Netherlands)

Dijk, van C.J.; Dueck, T.A.; Burgers, W.

2009-01-01

In deze studie worden de mogelijke risico’s die het gebruik van biogas in de glastuinbouw met zich mee kunnen brengen zo goed mogelijk in beeld gebracht. Aan de hand van de samenstellingseisen in de aansluit' en Transport' voorwaarden Gas RNB en de resultaten van biogasanalyses bij vijf

Inert-Gas Condensed Co-W Nanoclusters: Formation, Structure and Magnetic Properties

Science.gov (United States)

Golkar-Fard, Farhad Reza

Rare-earth permanent magnets are used extensively in numerous technical applications, e.g. wind turbines, audio speakers, and hybrid/electric vehicles. The demand and production of rare-earth permanent magnets in the world has in the past decades increased significantly. However, the decrease in export of rare-earth elements from China in recent time has led to a renewed interest in developing rare-earth free permanent magnets. Elements such as Fe and Co have potential, due to their high magnetization, to be used as hosts in rare-earth free permanent magnets but a major challenge is to increase their magnetocrystalline anisotropy constant, K1, which largely drives the coercivity. Theoretical calculations indicate that dissolving the 5d transition metal W in Fe or Co increases the magnetocrystalline anisotropy. The challenge, though, is in creating a solid solution in hcp Co or bcc Fe, which under equilibrium conditions have negligible solubility. In this dissertation, the formation, structure, and magnetic properties of sub-10 nm Co-W clusters with W content ranging from 4 to 24 atomic percent were studied. Co-W alloy clusters with extended solubility of W in hcp Co were produced by inert gas condensation. The different processing conditions such as the cooling scheme and sputtering power were found to control the structural state of the as-deposited Co-W clusters. For clusters formed in the water-cooled formation chamber, the mean size and the fraction crystalline clusters increased with increasing power, while the fraction of crystalline clusters formed in the liquid nitrogen-cooled formation chamber was not as affected by the sputtering power. For the low W content clusters, the structural characterization revealed clusters predominantly single crystalline hcp Co(W) structure, a significant extension of W solubility when compared to the equilibrium solubility, but fcc Co(W) and Co3W structures were observed in very small and large clusters, respectively. At high

Fluorescentievingerafdruk van Aardappel, Melganzenvoet en Mais : Eerste resultaten van plantonderscheid met behulp van fluorescentie

NARCIS (Netherlands)

Groot, T.T.; Nieuwenhuizen, A.T.

2012-01-01

Als het spectrum van één “soort” (gewas) vergeleken wordt met de rest (onkruid) neemt het onderscheid van het “gewas” af tot 70%. Het lijkt dus nodig ook de spectra van alle soorten onkruid in het veld te kennen om een goed onderscheid mogelijk te maken. De doelstelling voor deze metingen is een

Aqueous Rare Earth Element Patterns and Concentration in Thermal Brines Associated With Oil and Gas Production

Energy Technology Data Exchange (ETDEWEB)

Nye, Charles [University of Wyoming; Quillinan, Scott Austin [University of Wyoming; Neupane, Ghanashyam [Idaho National Lab. (INL), Idaho Falls, ID (United States); McLing, Travis [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2017-02-13

This study is part of a joint effort by the University of Wyoming (UW) School of Energy Resources (SER), the UW Engineering Department, Idaho National Laboratories (INL), and the United States Geological Survey (USGS) to describe rare earth element concentrations in oil and gas produced waters and in coal-fired power station ash ponds. In this work we present rare earth element (REE) and trace metal behavior in produced water from four Wyoming oil and gas fields and surface ash pond water from two coal-fired power stations. The concentration of REEs in oil and gas produced waters is largely unknown. For example, of the 150,000 entries in the USGS National Produced Waters Geochemical Database less than 5 include data for REEs. Part of the reason for this scarcity is the analytical challenge of measuring REEs in high salinity, hydrocarbon-bearing waters. The industry standard for water analysis struggles to detect REEs in natural waters under ideal conditions. The detection of REEs in oil and gas field samples becomes all but impossible with the background noise and interferences caused by high concentrations of non-REE ions and residual hydrocarbons. The INL team members have overcome many of these challenges (e.g. McLing, 2014), and continue to develop their methods. Using the methods of the INL team members we measured REEs in high salinity oil and gas produced waters. Our results show that REEs exist as a dissolved species in all waters measured for this project, typically within the parts per trillion range. The samples may be grouped into two broad categories analytically, and these categories match their genesis: Wyoming oil and gas brines contain elevated levels of Europium, and Wyoming industrial pond waters show elevation in heavy REEs (HREEs). While broadly true, important variations exist within both groups. In the same field Europium can vary by more than an order of magnitude, and likewise HREEs in industrial ponds at the same site can vary by more than

Proeven van tekstkritiek. Een onderzoek betreffende de tekstgeschiedenis van de Renout van Montalbaen en de Perceval

NARCIS (Netherlands)

Hogenhout-Mulder, Maaike Janna

1984-01-01

In dit proefschrift wordt een poging gedaan de tekstgeschiedenis te achterhalen van twee Middelnederlandse tekstfragmenten: een gedeelte uit de RENOUT VAN MONTALBAEN en een gedeelte uit de PERCEVAL. ... Zie: Twee tekstfragmenten als object van onderzoek

Risk Evaluation of the Use of Green Gas in Dutch greenhouses; Risico-evaluatie toepassing Groen Gas in de Nederlandse Glastuinbouw

Energy Technology Data Exchange (ETDEWEB)

Van Dijk, C.J. [Plant Research International PRI, Wageningen (Netherlands); Dueck, Th.A. [Wageningen UR Glastuinbouw, Wageningen (Netherlands); Burgers, W. [Infomil, Den Haag (Netherlands)

2009-01-15

information is available to estimate the possible risks of the remaining components in biogas. The approach in this study represents a worst case scenario because in common practice biogas will be mixed in the existing natural gas network before distributing it to greenhouses. It should be noted that even now, the use of flue gas emitted from combined heat power engines burning natural gas can result in nitrogen oxide concentrations that exceed the effective risk concentration under certain conditions. These effective risk concentrations have in some cases already resulted in negative effects on the growth and production of some greenhouse crops. These risks are independent of the use of biogas as fuel for combined heat power engines. If Dutch horticulturists are to use biogas on a large scale, it is essential that the maximum permissible concentrations be reduced for hydrogen fluoride (by a factor 20), sulphur dioxide (factor 2) and possibly benzene as well (factor 1.7). This is necessary in order to prevent these components becoming a potential risk to greenhouse crops. In addition, more research is advocated on the phytotoxicity of components for which insufficient information is presently available for the estimation of possible risks. [Dutch] Groen Gas (biogas) afkomstig uit vergistings- en vergassingsinstallaties kan een bijdrage leveren aan de energievoorziening als vervanger van fossiel aardgas. Het ambitieniveau ligt op 50% aardgasvervanging in 2050. In de Nederlandse glastuinbouw worden momenteel hoofdzakelijk aardgasgestookte WKK-installaties gebruikt. De installaties leveren elektriciteit voor belichting en levering aan het net, warmte voor de kas en rookgassen voor kooldioxide (CO2) productie t.b.v. gewasgroei en -productie. De glastuinbouwsector wordt als een belangrijke speler gezien voor de afzet van biogas. Indien op grote schaal geproduceerd biogas direct of na toevoeging aan het bestaande aardgasnet als brandstof wordt gebruikt voor installaties in de

Multi-quantum excitation in optically pumped alkali atom: rare gas mixtures

Science.gov (United States)

Galbally-Kinney, K. L.; Rawlins, W. T.; Davis, S. J.

2014-03-01

Diode-pumped alkali laser (DPAL) technology offers a means of achieving high-energy gas laser output through optical pumping of the D-lines of Cs, Rb, and K. The exciplex effect, based on weak attractive forces between alkali atoms and polarizable rare gas atoms (Ar, Kr, Xe), provides an alternative approach via broadband excitation of exciplex precursors (XPAL). In XPAL configurations, we have observed multi-quantum excitation within the alkali manifolds which result in infrared emission lines between 1 and 4 μm. The observed excited states include the 42FJ states of both Cs and Rb, which are well above the two-photon energy of the excitation laser in each case. We have observed fluorescence from multi-quantum states for excitation wavelengths throughout the exciplex absorption bands of Cs-Ar, Cs-Kr, and Cs-Xe. The intensity scaling is roughly first-order or less in both pump power and alkali concentration, suggesting a collisional energy pooling excitation mechanism. Collisional up-pumping appears to present a parasitic loss term for optically pumped atomic systems at high intensities, however there may also be excitation of other lasing transitions at infrared wavelengths.

Invoering van algemene vaardigheden: mogelijkheden van een vakoverstijgende aanpak

NARCIS (Netherlands)

Leenders, F.J.

2003-01-01

Centrale vraag: Het onderzoek richtte zich op de implementatie van vakoverstijgend vaardighedenonderwijs in de Tweede Fase van het voortgezet onderwijs. Belangrijkste conclusies: De brochure bevat onder meer een beschrijving van vijf scholen waar op verschillende wijze vaardighedenonderwijs

Resultaten van het Rijkswaterstaat JAMP 2009 monitoringsprogramma van bot (Platichthys flesus L.). Biologische gegevens van bot en milieukritische stoffen in bot

OpenAIRE

Hoek-van Nieuwenhuizen, van, M.; Barneveld, van, E.

2010-01-01

De in dit rapport beschreven werkzaamheden zijn in 2009 door IMARES uitgevoerd op basis van een opdracht van Rijkswaterstaat in het kader van het Joint Assessment and Monitoring Program van de OSPARCOM. De opdracht hield in het verkrijgen van biologische gegevens van bot (visziekten). De benodigde monsters bot werden verzameld door IMARES. Tevens werd materiaal van bot verzameld voor chemisch onderzoek en geanalyseerd.

Resultaten van het Rijkswaterstaat JAMP 2008 monitoringsprogramma van bot (Platichthys flesus L.). Biologische gegevens van bot en milieukritische stoffen in bot

NARCIS (Netherlands)

Hoek-van Nieuwenhuizen, van M.; Barneveld, van E.

2009-01-01

De in dit rapport beschreven werkzaamheden zijn door Wageningen IMARES uitgevoerd op basis van een opdracht van Rijkswaterstaat in het kader van het Joint Assessment and Monitoring Program van de OSPARCOM. De opdracht hield in het verkrijgen van biologische gegevens van bot. De benodigde monsters

Afbouw van het Wsw-bestand: actualisatie op basis van Wsw-gegevens ultimo 2013

NARCIS (Netherlands)

Berden, C.; Tempelman, C.

2014-01-01

In opdracht van het ministerie van Sociale Zaken en Werkgelegenheid heeft SEO Economisch Onderzoek onderzoek gedaan naar de verdeling van het Participatiebudget over gemeenten. Een onderdeel van dit onderzoek vormde het voorspellen van de afbouw van het huidige zittend bestand in de Wsw op basis van

Interatomic decay of inner-valence ionized states in ArXe clusters: Relativistic approach

International Nuclear Information System (INIS)

Fasshauer, Elke; Pernpointner, Markus; Gokhberg, Kirill

2013-01-01

In this work we investigate interatomic electronic decay processes taking place in mixed argon-xenon clusters upon the inner-valence ionization of an argon center. We demonstrate that both interatomic Coulombic decay and electron-transfer mediated decay (ETMD) are important in larger rare gas clusters as opposed to dimers. Calculated secondary electron spectra are shown to depend strongly on the spin-orbit coupling in the final states of the decay as well as the presence of polarizable environment. It follows from our calculations that ETMD is a pure interface process taking place between the argon-xenon layers. The interplay of all these effects is investigated in order to arrive at a suitable physical model for the decay of inner-valence vacancies taking place in mixed ArXe clusters.

Laser ionization of molecular clusters

International Nuclear Information System (INIS)

Desai, S.; Feigerle, C.S.

1995-01-01

Multiphoton ionization coupled with mass spectrometry was used to investigate molecular cluster distributions. Three examples will be discussed in this presentation. First, in studies of neat nitric oxide clusters, (NO) m , an interesting odd-even intensity alternation was observed and will be discussed in terms of electron-pairing considerations. In a separate study, the binary clusters comprising nitric oxide and methane preferentially form a stoichiometric cluster made up of repeating units of (NO) 2 CH 4 . These presumably represent a particularly strongly bound open-quotes van der Waalsclose quotes subunit. Finally, in similar studies of neat carbon disulfide clusters, (CS 2 ) m , additional photon absorption after the two-photon ionization step stimulates a series of intracluster ion-molecular reactions leading to formation of S m + and (CS) m + polymers, as well as intermediate species such as S m + (CS 2 ). This molecular cluster analogue of open-quotes laser snowclose quotes will be described in detail

Resultaten van het Rijkswaterstaat JAMP 2009 monitoringsprogramma van bot (Platichthys flesus L.). Biologische gegevens van bot en milieukritische stoffen in bot

NARCIS (Netherlands)

Hoek-van Nieuwenhuizen, van M.; Barneveld, van E.

2010-01-01

De in dit rapport beschreven werkzaamheden zijn in 2009 door IMARES uitgevoerd op basis van een opdracht van Rijkswaterstaat in het kader van het Joint Assessment and Monitoring Program van de OSPARCOM. De opdracht hield in het verkrijgen van biologische gegevens van bot (visziekten). De benodigde

Radioactive rare gas recoverying device

International Nuclear Information System (INIS)

Kasai, Shigeo

1989-01-01

The apparatus of the present invention comprises a vessel for containing coolants, an introduction valve and an introduction pipe for introducing radioactive rare gases and an adsorption floor disposed in the coolants. A josephson device is disposed being immersed in the coolants between a radiation detector for detecting the radioactive level adsorbed to the adsorption floor and a driving section for driving the introduction valve by the signal from the detector. With this constitution, radioactive rare gases introduced into the coolants and then cooled and liquefied are recovered by the adsorption floor. As the adsorption proceeds and when the radioactivity level exceeds a maximum level in the effective shielding range of the recovery apparatus, the signal current from the radiation detector also exceeds a predetermined level. If radioactivity exceeds the maximum level, the electrical resistance of the josephson device is increased infinitely by the josephson effect to close the introduction valve. Accordingly, the radioactivity is not absorbed beyond the effective shielding range. (I.S.)

Die beskerming van biologiese diversiteit deur gebruik te maak van die gevoeligheidsvariasie van spesies vir toksiese stowwe

Directory of Open Access Journals (Sweden)

A. J. Reinecke

2003-09-01

Full Text Available Pogings om algemeen geldende standaarde of maatstawwe vir omgewingskwaliteit op te stel vir die beskerming van Suid-Afrika se ryk biodiversiteit word bemoeilik deur die feit dat spesies baie kan verskil  ten opsigte van hulle gevoeligheid vir toksiese stowwe. Daar kan dus nie sonder meer vanaf een spesie na ’n ander geëkstrapoleer word nie. Deur egter juis gebruik te maak van hierdie variasie in gevoeligheid van spesies, kan die assessering van die risiko wat besoedelingstowwe vir organismes inhou wel op ’n meer wetenskaplike grondslag bedryf word. Hierdie konsep gaan uit van die standpunt dat indien kwaliteitskriteriums opgestel word wat die sensitiefste spesies beskerm, alle ander spesies outomaties beskerm word. Hierdie bydrae fokus op die gebruik van sensitiwiteitsverspreidings van spesies as metode en kyk oorsigtelik en krities na die aard en toepassings van die ekstrapolasiemodelle wat op hierdie verspreidings gebaseer is. Die moontlike aanwending daarvan en die argumente ten gunste daarvan en daarteen word bespreek. Die gevolgtrekking word gemaak dat spesie-sensitiwiteitsverspreidings wel nuttige aanwending kan vind, maar dat  gegewens oor die gevoeligheid van plaaslike spesies  baie skaars is. Hoewel dit reeds bruikbaar is, kan die algemene aanwending daarvan  in Suid-Afrika aansienlik uitgebrei word indien meer navorsing gedoen word om betroubare toksisiteitsgegewens vir verskillende spesies in te win, sodat die model meer verfyn kan word. Daarvoor moet gestandaardiseerde toksisiteitstoetse vir plaaslike spesies eers ontwikkel word.

Gevolgen van hydrocephalus

NARCIS (Netherlands)

Tromp, Cornelis Nicolaas

1984-01-01

Hydrocephalus is een aandoening van het centrale zenuwstelsel die de clinicus vrij lang voor grote problemen ten aanzien van de behandeling heeft qesteld. Door de toepassing van de ventriculo-atriale shunttechniek zijn de behandelingsmogelijkheden van hydrocephalus sterk verbeterd. Deze studie

Overzicht van de onderzoekresultaten van kroketten, bitterballen en frikandellen van 1986

NARCIS (Netherlands)

Cazemier, G.; Veen, van der N.G.

1987-01-01

In 1986 werden in opdracht van de AID 54 monsters frikandellen en 237 monsters kroketten en bitterballen door het RIKILT onderzocht op de eisen, zoals die zijn vastgelegd in de Kwaliteitsverordening Kroketten, Bitterballen en Frika(n)dellen. In dit verslag zijn de analyseresultaten van deze monsters

Monitoring of the natural gas exploitation in the Wadden Sea from the locations Moddergat, Lauwersoog and Vierhuizen, Netherlands. Advice of the Audit Committee 2011; Monitoring van de aardgaswinning onder de Waddenzee vanaf de locaties Moddergat, Lauwersoog en Vierhuizen. Advies 2011 van de Auditcommissie

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-04-15

The Dutch governmental decree ('Rijksprojectenbesluit') on the project for natural gas exploitation in the Wadden Sea for the locations Moddergat, Lauwersoog and Vierhuizen gives the Dutch Petroleum Company (NAM) the possibility to produce natural gas under specific conditions in the Wadden Sea area from the six fields Moddergat, Nes, Lauwersoog C, Lauwersoog West, Lauwersoog East and Vierhuizen East. The precondition is that the (dynamic) nature in and around the Wadden Sea is not affected by subsidence as a result of the gas exploitation. For this, the NAM must monitor the subsidence and the nature values and report annually to the Dutch government. Also in the Rijksprojectbesluit it is determined that the Commission for Environmental Impact Assessment (EIA), as the independent auditor, will annually advise the responsible ministers on the EIA-report. This is the 2011 recommendation of the Audit Committee for exploitation of natural gas in the Wadden Sea [Dutch] Het Rijksprojectbesluit Gaswinning onder de Waddenzee vanaf de locaties Moddergat, Lauwersoog en Vierhuizen geeft de Nederlandse Aardolie Maatschappij (NAM) de mogelijkheid om onder randvoorwaarden aardgas te produceren in het Waddenzeegebied uit de zes velden Moddergat, Nes, Lauwersoog C, Lauwersoog West, Lauwersoog Oost en Vierhuizen Oost. De randvoorwaarde is dat de (dynamische) natuur in en rondom de Waddenzee niet wordt aangetast door bodemdaling als gevolg van de gaswinning. Daarvoor moet de NAM de bodemdaling en de natuurwaarden monitoren en jaarlijks rapporteren aan de Nederlandse overheid. Ook is in het Rijksprojectbesluit bepaald dat de Commissie voor de milieueffectrapportage (m.e.r.) als onafhankelijke auditor de verantwoordelijke ministers jaarlijks zal adviseren over deze Rapportage. Dit is het 2011 advies van de Auditcommissie gaswinning onder de Waddenzee.

Monitoring of the natural gas exploitation in the Wadden Sea from the locations Moddergat, Lauwersoog and Vierhuizen, Netherlands. Advice of the Audit Committee 2009; Monitoring van de aardgaswinning onder de Waddenzee vanaf de locaties Moddergat, Lauwersoog en Vierhuizen. Advies 2009 van de Auditcommissie

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-05-07

The Dutch governmental decree ('Rijksprojectenbesluit') on the project for natural gas exploitation in the Wadden Sea for the locations Moddergat, Lauwersoog Vierhuizen gives the Dutch Petroleum Company (NAM) the possibility to produce natural gas under specific conditions in the Wadden Sea area from the six fields Moddergat, Nes, Lauwersoog C, Lauwersoog West, Lauwersoog East and Vierhuizen East. The precondition is that the (dynamic) nature in and around the Wadden Sea is not affected by subsidence as a result of the gas exploitation. For this, the NAM must monitor the subsidence and the nature values and report annually to the Dutch government. Also in the Rijksprojectbesluit it is determined that the Commission for Environmental Impact Assessment (EIA), as the independent auditor, will annually advise the responsible ministers on the EIA-report. This is the 2009 recommendation of the Audit Committee for exploitation of natural gas in the Wadden Sea. [Dutch] Het Rijksprojectbesluit Gaswinning onder de Waddenzee vanaf de locaties Moddergat, Lauwersoog en Vierhuizen geeft de Nederlandse Aardolie Maatschappij (NAM) de mogelijkheid om onder randvoorwaarden aardgas te produceren in het Waddenzeegebied uit de zes velden Moddergat, Nes, Lauwersoog C, Lauwersoog West, Lauwersoog Oost en Vierhuizen Oost. De randvoorwaarde is dat de (dynamische) natuur in en rondom de Waddenzee niet wordt aangetast door bodemdaling als gevolg van de gaswinning. Daarvoor moet de NAM de bodemdaling en de natuurwaarden monitoren en jaarlijks rapporteren aan de Nederlandse overheid. Ook is in het Rijksprojectbesluit bepaald dat de Commissie voor de milieueffectrapportage (m.e.r.) als onafhankelijke auditor de verantwoordelijke ministers jaarlijks zal adviseren over deze Rapportage. Dit is het 2009 advies van de Auditcommissie gaswinning onder de Waddenzee.

Monitoring of the natural gas exploitation in the Wadden Sea from the locations Moddergat, Lauwersoog and Vierhuizen, Netherlands. Advice of the Audit Committee 2010; Monitoring van de aardgaswinning onder de Waddenzee vanaf de locaties Moddergat, Lauwersoog en Vierhuizen. Advies 2010 van de Auditcommissie

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-10-15

The Dutch governmental decree ('Rijksprojectenbesluit') on the project for natural gas exploitation in the Wadden Sea for the locations Moddergat, Lauwersoog and Vierhuizen gives the Dutch Petroleum Company (NAM) the possibility to produce natural gas under specific conditions in the Wadden Sea area from the six fields Moddergat, Nes, Lauwersoog C, Lauwersoog West, Lauwersoog East and Vierhuizen East. The precondition is that the (dynamic) nature in and around the Wadden Sea is not affected by subsidence as a result of the gas exploitation. For this, the NAM must monitor the subsidence and the nature values and report annually to the Dutch government. Also in the Rijksprojectbesluit it is determined that the Commission for Environmental Impact Assessment (EIA), as the independent auditor, will annually advise the responsible ministers on the EIA-report. This is the 2010 recommendation of the Audit Committee for exploitation of natural gas in the Wadden Sea. [Dutch] Het Rijksprojectbesluit Gaswinning onder de Waddenzee vanaf de locaties Moddergat, Lauwersoog en Vierhuizen geeft de Nederlandse Aardolie Maatschappij (NAM) de mogelijkheid om onder randvoorwaarden aardgas te produceren in het Waddenzeegebied uit de zes velden Moddergat, Nes, Lauwersoog C, Lauwersoog West, Lauwersoog Oost en Vierhuizen Oost. De randvoorwaarde is dat de (dynamische) natuur in en rondom de Waddenzee niet wordt aangetast door bodemdaling als gevolg van de gaswinning. Daarvoor moet de NAM de bodemdaling en de natuurwaarden monitoren en jaarlijks rapporteren aan de Nederlandse overheid. Ook is in het Rijksprojectbesluit bepaald dat de Commissie voor de milieueffectrapportage (m.e.r.) als onafhankelijke auditor de verantwoordelijke ministers jaarlijks zal adviseren over deze Rapportage. Dit is het 2010 advies van de Auditcommissie gaswinning onder de Waddenzee.

ʼn Kritiese evaluering van wetgewing wat die gesondheid van ...

African Journals Online (AJOL)

User

gereguleer wat "basiese watervoorsiening" omskryf as "die voorgeskrewe minimum standaard van watervoorsieningsdienste wat nodig is vir die betroubare voorsiening van ʼn toereikende hoeveelheid en gehalte water aan huishoudings, met inbegrip van informele huishoudings, om lewe en persoonlike higiëne te steun".

Phalonidia manniana, een complex van twee soorten: Ph. manniana en Ph. udana (Lepidoptera: Tortricidae)

NARCIS (Netherlands)

Groenen, F.; Huisman, K.J.; Doorenweerd, C.

2013-01-01

Tijdens het project om van alle Noord-Europese vlinders de DNA-barcode te bepalen, zijn bij Phalonidia manniana, in voornamelijk Scandinavisch materiaal, twee clusters gevonden. Bij verder morfologisch onderzoek zijn constante verschillen gevonden in het uiterlijk en de mannelijke en vrouwelijke

Karakterisering van het Etimologiewoordeboek van Afrikaans (EWA

Directory of Open Access Journals (Sweden)

Fons Moerdijk

2011-10-01

Full Text Available

Samenvatting: Zesendertig jaar na Afrikaanse etimologieë van Boshoff en Nienaber verscheener in 2003 een nieuw etymologisch woordenboek van het Afrikaans: het Etimologiewoordeboek vanAfrikaans (EWA. Tussen die twee woordenboeken bestaat een wezenlijk verschil. Het werk vanBoshoff en Nienaber is vrijwel alleen toegankelijk voor specialisten en niet specifiek bedoeld vooreen breed publiek. EWA is juist allereerst bestemd voor de leek die zich interesseert voor de oorsprongen de geschiedenis van de eigen taal. Daarnaast biedt het ook de etymoloog en historischtaalkundige een hoop gegevens en inspiratie voor nader onderzoek. Als etymologisch woordenboekbezit EWA een aantal bijzondere, eigen kenmerken. De selectie van de woorden is bepaalddoor het beoogde gebruikerspubliek. Als gevolg daarvan bevat EWA verscheidene typen woordendie in traditionele etymologische woordenboeken doorgaans veronachtzaamd worden, zoals afleidingen,samenstellingen, neologismen en gemeenzame spreektaalwoorden. De artikelstructuurwordt gekenmerkt door een hoge graad van uniformiteit en consistentie. Het accent ligt op dezogenaamde etymologia proxima, de etymologie waarbij men één stap teruggaat en de meestdirecte herkomst van het woord biedt. Voorts is speciale aandacht besteed aan polysemie: nietalleen de herkomst van de dominante betekenis van een woord wordt gegeven, maar ook die vanzijn eventuele andere betekenis(sen. Benoemingsmotieven komen ook veelvuldig aan bod. In eeneventuele tweede druk zouden opvallende verschillen in vorm of betekenis altijd verklaard of inieder geval besproken moeten worden. Dat blijft nu nogal eens achterwege. Ook zou voorafgaandaan zo'n volgende editie meer onderzoek naar woordhistorisch materiaal uit primaire bronnenvoor met name de 17de–19de eeuw verricht moeten worden. Het zou mooi zijn als deze eersteuitgave van EWA de aanleiding tot een dergelijk onderzoek zou vormen.

Sleutelwoorden: BENOEMINGSMOTIEF, ETYMOLOGIA PROXIMA

Rare nocturnal headaches.

Science.gov (United States)

Cohen, Anna S; Kaube, Holger

2004-06-01

This review describes rare headaches that can occur at night or during sleep, with a focus on cluster headaches, paroxysmal hemicrania, short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing, hypnic headache and exploding head syndrome. It is known that cluster headaches and hypnic headache are associated with rapid eye movement sleep, as illustrated by recent polysomnographic studies. Functional imaging studies have documented hypothalamic activation that is likely to be of relevance to circadian rhythms. These headache syndromes have been shown to respond to melatonin and lithium therapy, both of which have an indirect impact on the sleep-wake cycle. There is growing evidence that cluster headache and hypnic headache are chronobiological disorders.

Kwantificatie van de invloed van regen op de verkeerdoorstroming

NARCIS (Netherlands)

Calvert, S.C.; Van Stralen, W.; Molin, E.J.E.

2013-01-01

Kwantificatie van de invloed van regen op de verkeerdoorstroming Het is bekend dat het weer invloed heeft op het verkeer op snelwegen, en in het bijzonder filevorming. Op de eerste plaats wordt de wegcapaciteit tijdelijk beïnvloed door een verandering in rijgedrag van bestuurders. Ten tweede

The environmental effects of taxes on packages; De milieueffecten van de verpakkingenbelasting

Energy Technology Data Exchange (ETDEWEB)

Schroten, A.; Nelissen, D.; Bergsma, G.C.; Blom, M.J.

2010-08-15

The results of an evaluation of the environmental impacts of taxes for packages are presented, differentiated for greenhouse gas emissions. The evaluation used a qualitative analysis of information from eighteen depth-interviews with experts in the packaging market, foreign experiences, relevant price elasticities and 'expert guesses'. It appears that tax package so far had a limited effect on the packaging market. For the longer term (ten years) larger, but probably also limited, effects are expected. The environmental impact of packaging tax can be increased if the taxes are substantially increased. [Dutch] De resultaten van een evaluatie van de milieueffecten van de (naar broeikasgasemissies gedifferentieerde) verpakkingenbelasting worden gepresenteerd. In deze evaluatie is gebruik gemaakt van een kwalitatieve analyse van informatie uit achttien diepte-interviews met spelers op de verpakkingenmarkt, buitenlandse ervaringen, relevante prijselasticiteiten en 'expert guesses'. Het beeld dat de uitgevoerde evaluatie oplevert is dat de verpakkingenbelasting tot nu toe een beperkt effect heeft gehad op de verpakkingenmarkt. Voor de langere termijn (ca. tien jaar) worden grotere, maar waarschijnlijk beperkte, effecten verwacht. De milieueffecten van de verpakkingenbelasting zouden vergroot kunnen worden als de belastingtarieven substantieel worden verhoogd.

Resultaten van het RWS-RIKZ JAMP 2005 monitoringsprogramma van bot (Platichthys flesus L.) : Biologische gegevens van bot en milieukritische stoofen in bot

NARCIS (Netherlands)

Kotterman, M.J.J.

2006-01-01

In opdracht van RWS-RIKZ werden door het RIVO werkzaamheden uitgevoerd in het kader van het Joint Assessment and Monitoring Program van de OSPARCOM. De opdracht hield in het verkrijgen van biologische gegevens van bot. De werkzaamheden bestonden uit het verzamelen van monsters bot waarvan

'Uytnemende Schilder van Antwerpen' : Joos van Cleve: atelier, productie en werkmethoden

NARCIS (Netherlands)

Leeflang, Micha

2007-01-01

Joos van Cleve (ca. 1480-1541) was een van de meest invloedrijke Antwerpse schilders in de eerste helft van dezestiende eeuw. Hij kreeg belangrijke opdrachten voor portretten en altaarstukken van onder anderen de Franse koning Frans I. Micha Leeflang onderzocht met name de materieel-technische

Refloating stranded gas. Floating LNG-factory to become the largest ship on the world seas; Gestrand gas vlot trekken. Drijvende LNG-fabriek wordt grootste schip op wereldzeeen

Energy Technology Data Exchange (ETDEWEB)

De Wit, P.

2010-09-15

Great effort is currently put in the upcoming construction of a gigantic floating LNG plant that will be deployed by Shell. The enormous vessel will be used for the production of gas fields that are so far away from the coast that it is uneconomical to bring the gas to land by means of gas pipes, where it is converted into liquid natural gas (LNG). According to recent plans the first floating LNG plant will be used at the Prelude gas field northwest of Australia. [Dutch] Momenteel wordt hard gewerkt aan de aanstaande bouw van een gigantisch drijvende LNG-fabriek die door Shell ingezet gaat worden. Het enorme vaartuig wordt gebruikt voor de productie van gasvelden die zo ver uit de kust liggen dat het oneconomisch is om het gas met pijpleidingen aan land te brengen om het daar om te zetten in vloeibaar aardgas, LNG. Volgens de huidige plannen wordt de eerste drijvende LNG-fabriek gebruikt voor het Prelude gasveld ten noord-westen van Australie.

Resultaten van het RWS-RIKZ JAMP 2006 monitoringsprogramma van bot (Platichthys flesus L.). Biologische gegevens van bot en milieukritische stoffen in bot

OpenAIRE

Kotterman, M.J.J.; Barneveld, van, E.

2007-01-01

De in dit rapport beschreven werkzaamheden werden door IMARES uitgevoerd op basis van een opdracht van Rijkswaterstaat- Rijksinstituut voor Kust en Zee (RIKZ) in het kader van het Joint Assessment and Monitoring Program van de OSPARCOM. De opdracht hield in het verkrijgen van biologische gegevens van bot. De benodigde monsters bot werden verzameld door IMARES. Tevens werd materiaal van bot verzameld voor chemisch onderzoek en geanalyseerd.

Toepassing van de basisvrachtbenadering op fosfaat van compost; advies

NARCIS (Netherlands)

Ehlert, P.A.I.

2005-01-01

Bij het vormgeven van het stelsel van gebruiksnormen is een maatschappelijke discussie ontstaan over de aanvoer van fosfaat met grond in compost en zwarte grond. Deze deskstudie gaat in op vragen die hierbij gesteld zijn. Het aandeel grond in compost en zwarte grond en de hoeveelheid fosfaat daarin

"Die beiteltjie" van N.P. van Wyk Louw en

African Journals Online (AJOL)

Tom

belangrike kenmerk van die postmodernisme is, wil ek dit nie tot abso- lute kenmerk verhef nie. Een van die .... oorgang vanaf 'n epistemologiese ingesteldheid tot 'n ontologiese ingesteldheid demonstreer en ..... the neglected and a whole range of phenomena which have been denied a history. Die formulering van die ...

Invioed van de zuurtegraad van varkensurine op de ammoniakemissie

NARCIS (Netherlands)

Eizing, A.; Aarnink, A.J.A.

1996-01-01

Dit rapport beschrijft het effect van een lagere urine-pH op de ammoniakemissie in een varkensstal. Het onderzoek is uitgevoerd in een modelopstelling met de zogenaamde stalsimulator, waarbij de invloed van de urine-pH op de ammoniakemissie werd onderzocht. Hiervoor werd de urine van vleesvarkens op

Electron impact ionization of large krypton clusters

Institute of Scientific and Technical Information of China (English)

Li Shao-Hui; Li Ru-Xin; Ni Guo-Quan; Xu Zhi-Zhan

2004-01-01

We show that the detection of ionization of very large van der Waals clusters in a pulsed jet or a beam can be realized by using a fast ion gauge. Rapid positive feedback electron impact ionization and fragmentation processes,which are initially ignited by electron impact ionization of the krypton clusters with the electron current of the ion gauge, result in the appearance of a progressional oscillation-like ion spectrum, or just of a single fast event under critical conditions. Each line in the spectrum represents a correlated explosion or avalanche ionization of the clusters.The phenomena have been analysed qualitatively along with a Rayleigh scattering experiment of the corresponding cluster jet.

Ontwerp van een interventie om de groenteconsumptie van jongeren te verhogen

NARCIS (Netherlands)

Gilissen, L.J.W.J.; Meer, van der I.M.; Reinders, M.J.; Sluis, van der A.A.; Woltering, E.J.

2011-01-01

In dit rapport zullen verschillende mogelijke strategieën besproken worden die ingezet kunnen worden om de consumptie van groenten door jongeren te verhogen. De centrale vragen van dit onderzoek zijn: 1) Hoe kunnen groenten in het eetpatroon van jongeren een vaste plek van voldoende omvang krijgen?

Fireworks in noble gas clusters a first experiment with the new "free-electron laser"

CERN Document Server

2002-01-01

An international group of scientists has published first experiments carried out using the new soft X-ray free-electron laser (FEL) at the research center DESY in Hamburg, Germany. Using small clusters of noble gas atoms, for the first time, researchers studied the interaction of matter with intense X-ray radiation from an FEL on extremely short time scales (1 page).

A functional bikaverin biosynthesis gene cluster in rare strains of Botrytis cinerea is positively controlled by VELVET.

Directory of Open Access Journals (Sweden)

Julia Schumacher

Full Text Available The gene cluster responsible for the biosynthesis of the red polyketidic pigment bikaverin has only been characterized in Fusarium ssp. so far. Recently, a highly homologous but incomplete and nonfunctional bikaverin cluster has been found in the genome of the unrelated phytopathogenic fungus Botrytis cinerea. In this study, we provided evidence that rare B. cinerea strains such as 1750 have a complete and functional cluster comprising the six genes orthologous to Fusarium fujikuroi ffbik1-ffbik6 and do produce bikaverin. Phylogenetic analysis confirmed that the whole cluster was acquired from Fusarium through a horizontal gene transfer (HGT. In the bikaverin-nonproducing strain B05.10, the genes encoding bikaverin biosynthesis enzymes are nonfunctional due to deleterious mutations (bcbik2-3 or missing (bcbik1 but interestingly, the genes encoding the regulatory proteins BcBIK4 and BcBIK5 do not harbor deleterious mutations which suggests that they may still be functional. Heterologous complementation of the F. fujikuroi Δffbik4 mutant confirmed that bcbik4 of strain B05.10 is indeed fully functional. Deletion of bcvel1 in the pink strain 1750 resulted in loss of bikaverin and overproduction of melanin indicating that the VELVET protein BcVEL1 regulates the biosynthesis of the two pigments in an opposite manner. Although strain 1750 itself expresses a truncated BcVEL1 protein (100 instead of 575 aa that is nonfunctional with regard to sclerotia formation, virulence and oxalic acid formation, it is sufficient to regulate pigment biosynthesis (bikaverin and melanin and fenhexamid HydR2 type of resistance. Finally, a genetic cross between strain 1750 and a bikaverin-nonproducing strain sensitive to fenhexamid revealed that the functional bikaverin cluster is genetically linked to the HydR2 locus.

The Morphologies and Alignments of Gas, Mass, and the Central Galaxies of CLASH Clusters of Galaxies

Science.gov (United States)

Donahue, Megan; Ettori, Stefano; Rasia, Elena; Sayers, Jack; Zitrin, Adi; Meneghetti, Massimo; Voit, G. Mark; Golwala, Sunil; Czakon, Nicole; Yepes, Gustavo; Baldi, Alessandro; Koekemoer, Anton; Postman, Marc

2016-03-01

Morphology is often used to infer the state of relaxation of galaxy clusters. The regularity, symmetry, and degree to which a cluster is centrally concentrated inform quantitative measures of cluster morphology. The Cluster Lensing and Supernova survey with Hubble Space Telescope (CLASH) used weak and strong lensing to measure the distribution of matter within a sample of 25 clusters, 20 of which were deemed to be “relaxed” based on their X-ray morphology and alignment of the X-ray emission with the Brightest Cluster Galaxy. Toward a quantitative characterization of this important sample of clusters, we present uniformly estimated X-ray morphological statistics for all 25 CLASH clusters. We compare X-ray morphologies of CLASH clusters with those identically measured for a large sample of simulated clusters from the MUSIC-2 simulations, selected by mass. We confirm a threshold in X-ray surface brightness concentration of C ≳ 0.4 for cool-core clusters, where C is the ratio of X-ray emission inside 100 h70-1 kpc compared to inside 500 {h}70-1 kpc. We report and compare morphologies of these clusters inferred from Sunyaev-Zeldovich Effect (SZE) maps of the hot gas and in from projected mass maps based on strong and weak lensing. We find a strong agreement in alignments of the orientation of major axes for the lensing, X-ray, and SZE maps of nearly all of the CLASH clusters at radii of 500 kpc (approximately 1/2 R500 for these clusters). We also find a striking alignment of clusters shapes at the 500 kpc scale, as measured with X-ray, SZE, and lensing, with that of the near-infrared stellar light at 10 kpc scales for the 20 “relaxed” clusters. This strong alignment indicates a powerful coupling between the cluster- and galaxy-scale galaxy formation processes.

Reductie van het kiemgetal van bacteriën op champignons : literatuuroverzicht

NARCIS (Netherlands)

Baars, J.J.P.

2006-01-01

Dit rapport bevat een literatuurstudie waarin een overzicht wordt gegeven van de beschikbare literatuur m.b.t. hoogte van het kiemgetal van bacteriën op champignons en de grondstoffen voor de champignonteelt, aanwezigheid van pathogene bacteriën op champignons die in de retail worden aangeboden en

Het handwerk van de theorie in de praktijk van het Sociaal Werk

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Hans Oostrik

2010-06-01

Sociaal werk is een narratieve praktijk. Vanuit een sociaal-constructivistische invalshoek, reflecteert de auteur in dit artikel op de vraag hoe vanuit deze narratieve praktijk tot theoretische handelingsmodellen kan worden gekomen. Drie elementen spelen daarbij een rol, welke door de auteur worden behandeld. Ten eerste zijn dat de vaardigheden van de professional, die bijdragen aan conceptualisering, zoals daar zijn: het signaleren van kwesties, het analyseren en vormen van begrippen en het ontwerpen van conceptuele modellen. Ten tweede kunnen theoretische modellen in de praktijk van het sociaal werk gebruikt worden als instrumenten om die praktijk als het ware te theoretiseren of reflectief te maken. De praktijk wordt met behulp van modellen zoals scenario’s en stappenplannen, verbeterd en verder ontwikkeld. Ten derde bestaat het handwerk van de theorie in het innemen van een theoretische houding of praktische verstandigheid waardoor sociaal werkers beter om kunnen gaan met de complexiteit van hun praktijk.

Effecten van wintergewassen op verliezen en benutting van stikstof bij de teelt van snijmaos; verslag van onderzoek op ROC Aver-Heino tussen voorjaar 1991 en najaar 1994

NARCIS (Netherlands)

Dijk, van W.; Schröder, J.J.; Holte, ten L.; Groot, de W.J.M.

1995-01-01

Tussen 1988 en 1994 is onderzoek verricht naar de effecten van wintergewassen (winterrogge en onderzaai van gras) op de verliezen en benutting van stikstof bij continuteelt van snijmaos op zandgrond. Gemiddeld over de gehele onderzoeksperiode nam zowel rogge als gras 30-40 kg/ha op in de

Cluster generator

Science.gov (United States)

Donchev, Todor I [Urbana, IL; Petrov, Ivan G [Champaign, IL

2011-05-31

Described herein is an apparatus and a method for producing atom clusters based on a gas discharge within a hollow cathode. The hollow cathode includes one or more walls. The one or more walls define a sputtering chamber within the hollow cathode and include a material to be sputtered. A hollow anode is positioned at an end of the sputtering chamber, and atom clusters are formed when a gas discharge is generated between the hollow anode and the hollow cathode.

Gebruik van TaqMan PCR voor het kwantificeren van Fusarium spp. en Microdochium nivale in gewassen en gewasresten van tarwe.

NARCIS (Netherlands)

Köhl, J.; Haas, de B.H.; Kastelein, P.; Burgers, S.L.G.E.; Waalwijk, C.

2005-01-01

Infecties van tarwe door toxigene Fusarium spp. kunnen leiden tot contaminatie van graan met diverse mycotoxines. Voorkoming van mycotoxinebesmetting is uit oogpunt van voedselveiligheid, diergezondheid, maar ook bedrijfseconomisch, vereist. Voor vier Fusariumsoorten is een kwantitatieve detectie

Van die Gasredakteur

African Journals Online (AJOL)

cherish and teach.'1. Die Fakulteit Geneeskunde van die Universiteit van die Oranje-Vrystaat het pragtig gegroei ge- durende die eerste 21 jaar van sy bestaan. Die entoesiasme, doelgerigtheid, harde werk en inisia- tiewe van 'n groot aantal persone was hiervoor verantwoordelik. 'If we see a bit more clearly than they, it is ...

De werking van de hydro- en acetylverbindingen van kinidine en kinine op het hart van Rana esculenta

NARCIS (Netherlands)

Sibie, Johan Dirk

1942-01-01

In hoofdstuk I werd een inleiding gegeven betreffende de geschiedenis van de kina en van het begin der kinacultuur op Java, de chemie der kinaälkaloïden en enkele aspecten der pharmacologische werking van de kinaderivaten. ... Zie: Samenvatting

Introductie van de Chevon : een zoektocht naar de afzet van geitenvlees

NARCIS (Netherlands)

Eleveld, I.; Louis Bolk,

2008-01-01

Het afmesten en afzetten van lammeren op een biologisch bedrijf is geen gemakkelijke weg. Aan de smaak van het vlees zal het niet liggen. De chevon, lammeren met een leeftijd van 5 tot 7 maand, geven vlees met karakter: een vleugje geit! De onbekendheid van het vlees vereist een zorgvuldige

Cosmological models described by a mixture of van der Waals fluid and dark energy

International Nuclear Information System (INIS)

Kremer, G.M.

2003-01-01

The Universe is modeled as a binary mixture whose constituents are described by a van der Waals fluid and by a dark energy density. The dark energy density is considered either as quintessence or as the Chaplygin gas. The irreversible processes concerning the energy transfer between the van der Waals fluid and the gravitational field are taken into account. This model can simulate (a) an inflationary period where the acceleration grows exponentially and the van der Waals fluid behaves like an inflaton, (b) an accelerated period where the acceleration is positive but it decreases and tends to zero whereas the energy density of the van der Waals fluid decays, (c) a decelerated period which corresponds to a matter dominated period with a non-negative pressure, and (d) a present accelerated period where the dark energy density outweighs the energy density of the van der Waals fluid

Chondroectodermal dysplasia (Ellis van Creveld syndrome: A report of three cases with review of literature

Directory of Open Access Journals (Sweden)

Kurian K

2007-01-01

Full Text Available Chondroectodermal dysplasia is a rare mesenchymal - ectodermal dysplasia first described in 1940 by Richard W.B. Ellis and Simon van Creveld now known as Ellis van Creveld syndrome. It is also known as Mesvectodermal dysplasia. Majority of cases were characteristically seen in one particular inbred population from the Amish community of Lancaster County, Pennsylvania, U.S.A. The syndrome manifests with several skeletal anomalies, oral mucosal and dental anomalies, congenital cardiac defects and nail dysplasia. Ellis van Creveld syndrome may be differentiated from other chondrodystrophies like achondroplasia, chondroplasia punctata, asphyxiating thorasic dystrophy and Morquio′s syndrome. The presence of oral mucosal and dental alterations like notching of the lower alveolar process, fusion of the upper lip with gingival mucosal margin, occasional presence of neonatal teeth, oligodontia and conical shape of anterior teeth will confirm the diagnosis of Ellis van Creveld syndrome and hence its importance to dentists.

Brightest Cluster Galaxies in REXCESS Clusters

Science.gov (United States)

Haarsma, Deborah B.; Leisman, L.; Bruch, S.; Donahue, M.

2009-01-01

Most galaxy clusters contain a Brightest Cluster Galaxy (BCG) which is larger than the other cluster ellipticals and has a more extended profile. In the hierarchical model, the BCG forms through many galaxy mergers in the crowded center of the cluster, and thus its properties give insight into the assembly of the cluster as a whole. In this project, we are working with the Representative XMM-Newton Cluster Structure Survey (REXCESS) team (Boehringer et al 2007) to study BCGs in 33 X-ray luminous galaxy clusters, 0.055 < z < 0.183. We are imaging the BCGs in R band at the Southern Observatory for Astrophysical Research (SOAR) in Chile. In this poster, we discuss our methods and give preliminary measurements of the BCG magnitudes, morphology, and stellar mass. We compare these BCG properties with the properties of their host clusters, particularly of the X-ray emitting gas.

De auteursrechtelijke aansprakelijkheid van intermediairs, het kabelpiratenarrest revisited in de tijd van Internet

NARCIS (Netherlands)

Dommering, E.J.; Verkade, D.W.F.; Visser, D.J.G.

1998-01-01

Het kabelpiratenarrest vestigde de auteursrechtelijke aansprakelijkheid van de kabelexploitant voor het verspreiden van gestolen films die clandestien na de uitzendingen van de reguliere omroepen werden uitgezonden met gebruikmaking van de centrale antenne-inrichting van KTA. Zouden wij de

De mislukte missie van mr. Maarten van Naarden als luitenant-stadhouder van Stad en Lande 1541-1557

Directory of Open Access Journals (Sweden)

F. Postma

2005-01-01

Full Text Available Maarten van Naarden’s failed mission  as lieutenant-stadholder of the province of Groningen, 1541-1557In November 1557, Maarten van Naarden resigned from his post as lieutenant-stadholder of the province of Groningen and left the province after staying there for sixteen years. Van Naarden’s resignation was preceded by a number of conflicts with the Groningen town council and the States of the province. However, these conflicts were neither confined to Van Naarden nor the province of Groningen. They had also taken place  in other provinces in the Northeast of the Netherlands. What makes Van Naarden’s clash with the Groningen provincial authorities in the 1550s so important is that it clarifies the principles that were at stake. These principles were less apparent in the conflicts between the representatives of the central government in Friesland, Overijssel and Gelderland. It was a struggle in which Van Naarden tried, as his opponents rightly saw it, to introduce the ‘constitution’ of Utrecht in the town and county of Groningen. In Utrecht, which had been annexed by Charles V in 1528, the autonomy of the province had been reduced to next to nothing. The only authority still resting with the States was the surveillance of the provincial dikes and waterways. All their other areas of authority had been taken over by the provincial court of which Van Naarden had been president between 1537 and 1541. To avoid the same thing happening to them, Van Naarden was ordered to appear before the Groningen States assembly in January 1556. At this meeting, the weakness of his position became crystal clear. None of the members took his side. Because the government lacked the means to keep Van Naarden in office, his withdrawal from Groningen was inevitable. What we see behind the story of Van Naarden more clearly than in the conflicts in the neighbouring provinces is the outline of the absolute state that Van Naarden’s superiors had in mind for the

DIE ROL VAN DIE TAALWETENSKAP IN DIE ONTWIKKELING VAN ...

African Journals Online (AJOL)

aanslag op die sogenaamde "Intentional Fallacy", heelwat verder. n. Mens sou hier eintlik ook op die invloed van Lacan se toepassing van. De Sacs sure op Freud moet wys, en op Macherey se Theory of Literary. Production. Barthes is naamlik besig om repressie teen te werk, en die teks as produksieproses in stede van ...

'n Voordrag van Adrianus van Seims oor hermeneutiek | Boshoff ...

African Journals Online (AJOL)

A lecture on hermeneutics by Adrianus van Seims This article is the content of a lecture on hermeneutics given by A van Seims. After a few opening words on the introduction to the lecture and its content, the presentation is reproduced in its entirety. Van Seims considers that hermeneutics is concerned not only with ...

"Krakende kaken"; psychiatrische beschouwingen over het syndroom van het pijnlijke, slecht functionerende kaakgewricht (Arthrosis deformans van het kaakgewricht of het syndroom van Costen)

NARCIS (Netherlands)

Schuler, Jacques

1966-01-01

Naar aanleiding van klinische indrukken en mede op grond van literatuurgegevens werd een psychiatrisch onderzoek verricht naar het aandeel van psychogene factoren bij het tot stand komen van kaakgewrichtsklachten. Het klachtencomplex dat van stoornissen in de functie van het kaakgewricht het gevolg

Voedselverspilling, waarden van voedsel in de keten : de mogelijke rol van het groene onderwijs bij het oplossen van een maatschappelijke opgave

OpenAIRE

Waarts, Y.R.; Onwezen, M.C.; Wiersinga, R.C.; Eppink, M.M.; Thoden van Velzen, E.U.; Timmermans, A.J.M.

2009-01-01

Het doel van deze verkenning is om op basis van literatuur en interviews met belangrijkste stakeholders een visie te formuleren over de wijze waarop het groene onderwijs een bijdrage kan leveren aan het verminderen van voedselverliezen binnen alle schakels van de keten inclusief de consument, en aan de nuttige toepassing van reststromen.

die impak van metodologie op die verstaan van die nuwe testament

African Journals Online (AJOL)

voorbeeld eers een maal deur die bril van die vorm- en redaksiekritiek na die Evangelies gekyk het, dink jy vir altyd anders oor hulle tot- standkoming. Inderdaad, nuwe metodes lei tot nuwe perspektiewe! Dit is dan ook waar die fokus van hierdie artikel val: die impak van metodologie op die verstaan van die Nuwe ...

The Association of Molecular Gas and Natal Super Star Clusters in Henize 2–10

Science.gov (United States)

Johnson, Kelsey E.; Brogan, Crystal L.; Indebetouw, Remy; Testi, Leonardo; Wilner, David J.; Reines, Amy E.; Chen, C.-H. Rosie; Vanzi, Leonardo

2018-02-01

We present ALMA observations of the dwarf starburst galaxy He 2–10 in combination with previous SMA CO observations to probe the molecular environments of natal super star clusters (SSCs). These observations include the HCO+(1-0), HCN(1-0), HNC(1-0), and CCH(1-0) molecular lines, as well as 88 GHz continuum with a spatial resolution of 1\\buildrel{\\prime\\prime}\\over{.} 7× 1\\buildrel{\\prime\\prime}\\over{.} 6. After correcting for the contribution from free–free emission to the 88 GHz continuum flux density (∼60% of the 88 GHz emission), we derive a total gas mass for He 2–10 of {M}{gas}=4{--}6× {10}8 M ⊙, roughly 5%–20% of the dynamical mass. Based on a principle component analysis, HCO+ is found to be the best “general” tracer of molecular emission. The line widths and luminosities of the CO emission suggests that the molecular clouds could either be as small as ∼8 pc, or alternately have enhanced line widths. The CO emission and 88 GHz continuum are anti-correlated, suggesting that either the dust and molecular gas are not cospatial, which could reflect that the 88 GHz continuum is dominated by free–free emission. The CO and CCH emission are also relatively anti-correlated, which is consistent with the CCH being photo-enhanced, and/or the CO being dissociated in the regions near the natal SSCs. The molecular line ratios of regions containing the natal star clusters are different from the line ratios observed for regions elsewhere in the galaxy. In particular, the regions with thermal radio emission all have {CO}(2{--}1)/{{HCO}}+(1-0)correlated with the evolutionary stage of the clusters.

Effectieve bestrijding van varroa

NARCIS (Netherlands)

Cornelissen, B.; Blacquiere, T.; Steen, van der J.J.M.

2010-01-01

De varroa mijtziekte (Varroa destructor) is de belangrijkste bedreiging van de Europese honingbij. Wintersterfte van honingbijen is in de meeste gevallen toe te schrijven aan deze ziekte. Deze brochure van de WUR biedt informatie over de biologie van varroa, de effecten van varroa op honingbijen en

Prediking aan die hand van die metafoor van fiksieskryf

African Journals Online (AJOL)

p1243322

HTS 64(3) 2008 siening van die self en waarheid. In die pre-moderne paradigma kan die dominante metafoor verstaan word aan die hand van 'n spieël wat die lig uit 'n transendente oorsprong weerkaats, terwyl die moderne paradigma uitgedruk word met die metafoor van 'n lamp wat 'n eie, oorspronklike lig binne die self.

’n Etiek van liefde: Die etiese perspektiewe van die Heidelbergse Kategismus

Directory of Open Access Journals (Sweden)

Koos Vorster

2013-06-01

Full Text Available Hierdie artikel behandel die etiese perspektiewe van die Heidelbergse Kategismus – een van die prominente belydenisskrifte in die gereformeerde tradisie. Die etiese relevansie is ingebed in die konfessie se verklaring van die tien gebooie. Die artikel verduidelik dat die etiek van die Heidelbergse Kategismus ten diepste ’n karakteretiek is en dat dit gelowiges oproep tot ’n etiek van liefde. Hierdie liefde sluit in liefde vir die verbondsgemeenskap, die bediening van die Woord, die heiligheid van God en die waardigheid van mense, die gemeenskap van die gelowiges, gesag, die lewe, die huwelik, privaatbesit en arbeid asook waarheid en geregtigheid. As gevolg van die sinekdogeekarakter van die wet is hierdie etiek van liefde vandag baie relevant. This article deals with the ethical relevance of one of the prominent confessions in the reformed tradition, namely the Heidelberg Cathechism. The ethical relevance lies in the confession’s elucidation of the ten commandments and its application to moral conduct. The article explains that the ethics of the Heidelberg Catechism is essentially a virtue ethics calling for an ethics of love. This love should include love for the covenantal communion, ministry of the Word, the holiness of God and the dignity of people, the communion of the saints, authority, life, marriage, private property and labour, and truth and justice. Due to the synecdochical character of the ten commandments this ethics of love is highy relevant in the present times.

Properties of clusters in the gas phase: V. Complexes of neutral molecules onto negative ions

International Nuclear Information System (INIS)

Keesee, R.G.; Lee, N.; Castleman, A.W. Jr.

1980-01-01

Ion--molecules association reactions of the form A - (B)/sub n1/-+B=A - (B)/sub n/ were studied over a range of temperatures in the gas phase using high pressure mass spectrometry. Enthalpy and entropy changes were determined for the stepwise clustering reactions of (1) sulfur dioxide onto Cl - , I - , and NO 2 - with n ranging from one to three or four, and onto SO 2 - and SO 3 - with n equal to one; and (2) carbon dioxide onto Cl - , I - , NO 2 - , CO 3 - , and SO 3 - with n equal to one. From these data and earlier hydration results, the order of the magnitude of the enthalpy changes on the association of the first neutral for a series of negative ions was found to parallel the gas-phase basicity of those anions. For any given ion, the relative order of the addition enthalpies among the neutrals was found to be dependent on the polarizabilities of the neutrals and on the covalency in the ion-neutral bond. Dispersion of charge via covalent bonding was found to affect significantly the succeeding clustering steps

Optimaliseren van een biovergister

NARCIS (Netherlands)

van der Bij, Joost; Rademaker, Mark; Visser, Klaas; de Vries, Herman

2014-01-01

Dit rapport beschrijft onderzoek van conversie van biomassa in een Swill-gasser geplaatst bij het Van der Valk restaurant in Cuijk. De Swill-gasser is een biomassa vergister voor restaurant afval. Het onderzoek heeft zich gericht op het optimaliseren van de data acquisitie en op het bepalen van de

Kenmerkend van hierdie afdeling is die tema van ouderdom wat in ...

African Journals Online (AJOL)

8 Apr 2016 ... Kenmerkend van hierdie afdeling is die tema van ouderdom wat in menige van die stories voorkom. Hier is dit die onvermydelike aftakelingsproses van die liggaam (en verstand) wat 'n beduidende invloed op die skrywer het. In verhale soos “Wat 'n lieflike geraas”, “Die ou met die overall”, “Lofredes en ...

Bepaling van enkele neurotransmitters, monoaminen, en metabolieten, met behulp van Continuous Flowapparatuur

NARCIS (Netherlands)

Eigeman L; Schonewille F; Borst M; van der Laan JW

1986-01-01

Bij het onderzoek in de psychofarmacologie kan kennis van de effecten van stoffen op de omzettingssnelheid van neurotransmitters een belangrijk aspect zijn. Met de huidige psychofarmaca lijken vooral de klassieke neurotransmitters zoals de monoaminen, noradrenaline, dopamine en serotonine van

Kansen voor conflictbemiddeling : Verslag van een onderzoek naar de toepassingsmogelijkheden van conflictbemiddeling

NARCIS (Netherlands)

Geveke, Henk; Plant, Ernelies; Thieme, Marianneke; Verberk, Marielle

1998-01-01

In opdracht van het Platform ADR, een klankbordgroep en denktank op het gebied van alternatieve geschilbeslechting, is onderzoek verricht naar de toepasbaarheid van een specifieke vorm van Alternative Dispute Resolution (ADR): conflictbemiddeling (mediation). De onderzoeksopdracht was als volgt: het

Discovery of nine extended ionized gas clouds in a z = 0.4 cluster

Energy Technology Data Exchange (ETDEWEB)

Yagi, Masafumi; Koyama, Yusei; Kodama, Tadayuki [Optical and Infrared Astronomy Division, National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan); Gu, Liyi [Research Center for the Early Universe, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0011 (Japan); Nakata, Fumiaki; Hattori, Takashi [Subaru Telescope, 650 North A' ohoku Place, Hilo, HI 96720 (United States); Yoshida, Michitoshi, E-mail: YAGI.Masafumi@nao.ac.jp [Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1, Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526 (Japan)

2015-02-01

From deep Hα imaging data of Suprime-Cam/Subaru, we discovered nine extended ionized gas clouds (EIG) around galaxies in the Abell 851 cluster (A851) at z = 0.4. We surveyed a 30 × 25 arcmin region, and the EIGs were found only near the cluster center (<2.3 arcmin ∼ 750 kpc). The parent galaxies of the EIGs are star-forming or post-starburst galaxies, all of which are spectroscopically confirmed members of the cluster. Four out of the nine parent galaxies show distortion of stellar distribution in the disk, which can be a sign of recent interaction, and the interaction may have made the EIGs. On the other hand, six parent galaxies (one overlaps those exhibiting distortion) show Hα emission without stars, which implies ram pressure stripping. The spectrum of the brightest parent galaxy shows a post-starburst signature and resembles the Hα stripped galaxies found in the Coma cluster. Meanwhile, two brightest parent galaxies in A851 are more massive than the EIG parent galaxies in the Coma cluster. This is consistent with a “downsizing” of star-forming galaxies, though it is still within the statistical variance. We also analyzed Suprime-Cam data of another z=0.39 cluster, CL0024+17, but found no EIGs. The key difference between A851 and CL0024+17 would be the existence of a subcluster colliding with the main body of A851, in which six or seven out of the nine parent galaxies in A851 exist, and the fraction of EIGs in the subcluster is significantly higher than the main subcluster of A851 and CL0024+17.

Discovery of nine extended ionized gas clouds in a z = 0.4 cluster

International Nuclear Information System (INIS)

Yagi, Masafumi; Koyama, Yusei; Kodama, Tadayuki; Gu, Liyi; Nakata, Fumiaki; Hattori, Takashi; Yoshida, Michitoshi

2015-01-01

From deep Hα imaging data of Suprime-Cam/Subaru, we discovered nine extended ionized gas clouds (EIG) around galaxies in the Abell 851 cluster (A851) at z = 0.4. We surveyed a 30 × 25 arcmin region, and the EIGs were found only near the cluster center (<2.3 arcmin ∼ 750 kpc). The parent galaxies of the EIGs are star-forming or post-starburst galaxies, all of which are spectroscopically confirmed members of the cluster. Four out of the nine parent galaxies show distortion of stellar distribution in the disk, which can be a sign of recent interaction, and the interaction may have made the EIGs. On the other hand, six parent galaxies (one overlaps those exhibiting distortion) show Hα emission without stars, which implies ram pressure stripping. The spectrum of the brightest parent galaxy shows a post-starburst signature and resembles the Hα stripped galaxies found in the Coma cluster. Meanwhile, two brightest parent galaxies in A851 are more massive than the EIG parent galaxies in the Coma cluster. This is consistent with a “downsizing” of star-forming galaxies, though it is still within the statistical variance. We also analyzed Suprime-Cam data of another z=0.39 cluster, CL0024+17, but found no EIGs. The key difference between A851 and CL0024+17 would be the existence of a subcluster colliding with the main body of A851, in which six or seven out of the nine parent galaxies in A851 exist, and the fraction of EIGs in the subcluster is significantly higher than the main subcluster of A851 and CL0024+17.

De mislukte missie van mr. Maarten van Naarden als luitenant-stadhouder van Stad en Lande 1541-1557

NARCIS (Netherlands)

Postma, F.

2005-01-01

Maarten van Naarden’s failed mission as lieutenant-stadholder of the province of Groningen, 1541-1557 In November 1557, Maarten van Naarden resigned from his post as lieutenant-stadholder of the province of Groningen and left the province after staying there for sixteen years. Van Naarden’s

Interaction of rare gas metastable atoms

International Nuclear Information System (INIS)

Wang, A.Z.F.

1977-11-01

The physical and chemical properties of metastable rare gas atoms are discussed and summarized. This is followed by a detailed examination of the various possible pathways whereby the metastable's excess electronic energy can be dissipated. The phenomenon of chemi-ionization is given special emphasis, and a theoretical treatment based on the use of complex (optical) potential is presented. This is followed by a discussion on the unique advantages offered by elastic differential cross section measurements in the apprehension of the fundamental forces governing the ionization process. The methodology generally adopted to extract information about the interaction potential for scattering data is also systematically outlined. Two widely studied chemi-ionization systems are then closely examined in the light of accurate differential cross section measurements obtained in this work. The first system is He(2 3 S) + Ar for which one can obtain an interaction potential which is in good harmony with the experimental results of other investigators. The validity of using the first-order semiclassical approximation for the phase shifts calculation in the presence of significant opacities is also discussed. The second reaction studied is He*+D 2 for which measurements were made on both spin states of the metastable helium. A self-consistent interaction potential is obtained for the triplet system, and reasons are given for not being able to do likewise for the singlet system. The anomalous hump proposed by a number of laboratories is analyzed. Total elastic and ionization cross sections as well as rate constants are calculated for the triplet case. Good agreement with experimental data is found. Finally, the construction and operation of a high power repetitively pulsed nitrogen laser pumped dye laser system is described in great details. Details for the construction and operation of a flashlamp pumped dye laser are likewise given

Hot gas in the cold dark matter scenario: X-ray clusters from a high-resolution numerical simulation

Science.gov (United States)

Kang, Hyesung; Cen, Renyue; Ostriker, Jeremiah P.; Ryu, Dongsu

1994-01-01

A new, three-dimensional, shock-capturing hydrodynamic code is utilized to determine the distribution of hot gas in a standard cold dark matter (CDM) model of the universe. Periodic boundary conditions are assumed: a box with size 85 h(exp -1) Mpc having cell size 0.31 h(exp -1) Mpc is followed in a simulation with 270(exp 3) = 10(exp 7.3) cells. Adopting standard parameters determined from COBE and light-element nucleosynthesis, sigma(sub 8) = 1.05, omega(sub b) = 0.06, and assuming h = 0.5, we find the X-ray-emitting clusters and compute the luminosity function at several wavelengths, the temperature distribution, and estimated sizes, as well as the evolution of these quantities with redshift. We find that most of the total X-ray emissivity in our box originates in a relatively small number of identifiable clusters which occupy approximately 10(exp -3) of the box volume. This standard CDM model, normalized to COBE, produces approximately 5 times too much emission from clusters having L(sub x) is greater than 10(exp 43) ergs/s, a not-unexpected result. If all other parameters were unchanged, we would expect adequate agreement for sigma(sub 8) = 0.6. This provides a new and independent argument for lower small-scale power than standard CDM at the 8 h(exp -1) Mpc scale. The background radiation field at 1 keV due to clusters in this model is approximately one-third of the observed background, which, after correction for numerical effects, again indicates approximately 5 times too much emission and the appropriateness of sigma(sub 8) = 0.6. If we have used the observed ratio of gas to total mass in clusters, rather than basing the mean density on light-element nucleosynthesis, then the computed luminosity of each cluster would have increased still further, by a factor of approximately 10. The number density of clusters increases to z approximately 1, but the luminosity per typical cluster decreases, with the result that evolution in the number density of bright

Ondersoek na ’n teoretiese onderskraging van boekkuns: Die toepassing van Bakhtin se dialogisme en heteroglossia op geselekteerde voorbeelde van kunstenaarsboeke

Directory of Open Access Journals (Sweden)

David Paton

2012-11-01

Full Text Available Onlangse navorsingsprojekte en konferensies oor boekkuns het gereageer op Johanna Drucker se oproep in 2005 dat noodsaaklike navorsingswerk gedoen moet word om ’n deegliker teoretiese basis vir die terrein van boekkunsproduksie te vestig. Die deelname van kunstenaars en ander praktisyns van boekkuns veroorsaak dat gesprekke en besprekings noodwendig en voorspelbaar neig na die praktyk en weg van die teorie. In die lig van die behoefte aan die bepaling van ’n toepaslike visie waarvolgens die kunsboek meer eksplisiet, ook teoreties, ondersoek kan word, ondersoek hierdie artikel Stéphane Mallarmé en Marcel Broodthaers se Un coup de dés publikasies, Buzz Spector se simplifiserende Marcel Broodthaers, Ulises Carrion se For fans and scholars alike, en Helen Douglas en Telfer Stokes se Real fiction. Hierdie spesifieke voorbeelde, en hulle onderlinge verbande en dialoog met mekaar, word ondersoek vanuit die perspektief van die Russiese filosoof en literêre teoretikus Mikhail Bakhtin se werk oor dialogisme en heteroglossia (‘ander-tongigheid’. Hierdie begrippe demonstreer die dialogiese, multivokale en veeltongige wisselwerking tussen en binne historiese werke as kultuuruitings. Deur die analise toon ek aan dat hierde begrippe toepaslike en funksionele raamwerke uitmaak vir die analise van spesifieke aspekte wat die teenwoordigheid van kunstenaarsboeke aankondig in die wêreld: selfbewustheid en omvattende diskoers wat wederkerend toepaslik is. Ek stel voor dat Bakthin se idees oor dialogisme en heteroglossie gebruik word as die teoretiese begronding van die kunstenaarsboek as ’n dinamiese visuele taal wat in ’n netwerk van ander tekste staan en deel is van die proses van die eindelose herbeskrywing van die wêreld.

Resultaten van het RWS-RIKZ JAMP 2006 monitoringsprogramma van bot (Platichthys flesus L.). Biologische gegevens van bot en milieukritische stoffen in bot

NARCIS (Netherlands)

Kotterman, M.J.J.; Barneveld, van E.

2007-01-01

De in dit rapport beschreven werkzaamheden werden door IMARES uitgevoerd op basis van een opdracht van Rijkswaterstaat- Rijksinstituut voor Kust en Zee (RIKZ) in het kader van het Joint Assessment and Monitoring Program van de OSPARCOM. De opdracht hield in het verkrijgen van biologische gegevens

Natural gas quality for the future. Executive Summary; Gaskwaliteit voor de toekomst. Management Samenvatting

Energy Technology Data Exchange (ETDEWEB)

Klooster, J.; Metselaar, E.; Warringa, G. [Arcadis, Rotterdam (NL); Levinsky, H.B. [KEMA, Arnhem (Netherlands); Van Rij, M.L.D. [KIWA, Rijswijk (Netherlands)

2011-03-15

By request of various market parties (suppliers and users of natural gas), the Dutch Ministry of Economic Affairs, Agriculture and Innovation (ELI) took a leading role in anticipating the future changes in gas quality. To integrate anticipated gases in the Dutch gas supply, measures will be required that can prevent the undesired effects on safety and effectiveness as mentioned in Part 1 of this study; at the same time the possible impact of these measures on security of supply must be minimized. This report summarizes the two sub reports. [Dutch] Het ministerie van Economische Zaken, Landbouw en Innovatie (ELI) heeft op verzoek van diverse marktpartijen (leveranciers en gebruikers van aardgas) de regie op zich genomen om te kunnen anticiperen op de toekomstige veranderende gaskwaliteit. Om verwachte gassen in te kunnen passen in de Nederlandse gaslevering, zijn maatregelen nodig om de in deel 1 van deze studie genoemde ongewenste effecten qua veiligheid en doelmatigheid te voorkomen, en tegelijk de mogelijke impact van deze maatregelen op de voorzieningszekerheid te minimaliseren. Dit rapport is een samenvatting van de 2 deelrapporten.

Voedingpraktyke en behoeftes van hulpbron-arm gemeenskappe deur die oë van laerskoolonderwysers

Directory of Open Access Journals (Sweden)

Ronel Ferreira

2013-02-01

Full Text Available In hierdie artikel bespreek ons die persepsies van onderwysers (n = 45 wat betref die voedingpraktyke van ’n steekproef laerskoolleerders en hul gesinne in ’n hulpbron-arm gemeenskap. Ons fokus spesifiek op die behoeftes, praktyke en verwagtings ten opsigte van die gebruik van voedsel, wat die produksie, keuse en voorbereiding van voedsel impliseer. Ons studie vorm die eerste deel van ’n groter institusionele navorsingprojek. Vir die doel van ons studie het ons deelnemende refleksie en aksie-gebaseerde werkwinkels gehou om data te genereer en tydens die interpretasie van bevindinge op interpretivisme staatgemaak. Hierdie studie beklemtoon die behoeftes van hulpbron-arm en werklose gemeenskapslede wat dikwels genoodsaak is om teen verlaagde pryse voedsel te koop waarvan die kwaliteit nie optimaal is nie. ’n Verskraalde ontbyt, middagete of aandete waarvan die keuse algemeen beperk is tot swart tee, pap en een of twee snye ou brood, bevestig die manifestasies van armoede in hulpbron-arm gemeenskappe. Maaltye is dikwels beperk tot groot hoeveelhede koolhidrate, min groente, ingelegde vis, pap met inkomazi en marog. Hoenderpote en afval vul soms die spyskaart aan. Onderwysers beklemtoon die feit dat gemeenskapslede tipies op skenkings van werkgewers, kerke en kruidenierswinkels staatmaak om hul voedselbegroting aan te vul. Onderwysers fokus verder op die behoeftes aan opleiding vir gemeenskapslede. Na hulle mening moet gemeenskappe ingelig word oor voedselproduksie, groentetuine, die wyses waarop die kwaliteit van grond bepaal kan word, besproeiing en die toepassing van volhoubare wisselbou. Die artikel word afgesluit met uitvoerbare en leersame wenke vir die opleiding van landelike gemeenskappe. Op grond van dié navorsingsbevindinge word ’n intervensieprogram tans ontwikkel, met die doel om dit in die onderskeie deelnemende skole te implementeer ter bevordering van gesonde voedselverwante gedrag en welsyn.

Beheersing van valse meeldauw in de akkerbouwmatige teelt van peterselie

NARCIS (Netherlands)

Mheen, van der H.J.C.J.; Lamers, J.G.

2009-01-01

In 2007 en 2008 heeft PPO-agv in opdracht van het Productwschap Akkerbouw onderzoek gedaan naar de beheersing van valse meeldauw in de akkerbouwmatige teelt van peterselie. Diverse fungicidentoepassingen zijn in staat om de peterselie (in meer of mindere mate) tegen valse meeldauw te beschermen.

Effects of oxygen addition in reactive cluster beam deposition of tungsten by magnetron sputtering with gas aggregation

Energy Technology Data Exchange (ETDEWEB)

Polášek, J., E-mail: xpolasekj@seznam.cz [Department of Surface and Plasma Science, Faculty of Mathematics and Physic, Charles University, V Holešovičkách 2, Prague 8, CZ-18000 (Czech Republic); Mašek, K. [Department of Surface and Plasma Science, Faculty of Mathematics and Physic, Charles University, V Holešovičkách 2, Prague 8, CZ-18000 (Czech Republic); Marek, A.; Vyskočil, J. [HVM Plasma Ltd., Na Hutmance 2, Prague 5, CZ-158 00 (Czech Republic)

2015-09-30

In this work, we investigated the possibilities of tungsten and tungsten oxide nanoclusters generation by means of non-reactive and reactive magnetron sputtering with gas aggregation. It was found that in pure argon atmosphere, cluster aggregation proceeded in two regimes depending on argon pressure in the aggregation chamber. At the lower pressure, cluster generation was dominated by two-body collisions yielding larger clusters (about 5.5 nm in diameter) at lower rate. At higher pressures, cluster generation was dominated by three-body collisions yielding smaller clusters (3–4 nm in diameter) at higher rate. The small amount of oxygen admixture in the aggregation chamber had considerable influence on cluster aggregation process. At certain critical pressure, the presence of oxygen led to the raise of deposition rate and cluster size. Resulting clusters were composed mostly of tungsten trioxide. The oxygen pressure higher than critical led to the target poisoning and the decrease in the sputtering rate. Critical oxygen pressure decreased with increasing argon pressure, suggesting that cluster aggregation process was influenced by atomic oxygen species (namely, O{sup −} ion) generated by oxygen–argon collisions in the magnetron plasma. - Highlights: • Formation of tungsten and tungsten oxide clusters was observed. • Two modes of cluster aggregation in pure argon atmosphere were found. • Dependence of cluster deposition speed and size on oxygen admixture was observed. • Changes of dependence on oxygen with changing argon pressure were described.

Effects of oxygen addition in reactive cluster beam deposition of tungsten by magnetron sputtering with gas aggregation

International Nuclear Information System (INIS)

Polášek, J.; Mašek, K.; Marek, A.; Vyskočil, J.

2015-01-01

In this work, we investigated the possibilities of tungsten and tungsten oxide nanoclusters generation by means of non-reactive and reactive magnetron sputtering with gas aggregation. It was found that in pure argon atmosphere, cluster aggregation proceeded in two regimes depending on argon pressure in the aggregation chamber. At the lower pressure, cluster generation was dominated by two-body collisions yielding larger clusters (about 5.5 nm in diameter) at lower rate. At higher pressures, cluster generation was dominated by three-body collisions yielding smaller clusters (3–4 nm in diameter) at higher rate. The small amount of oxygen admixture in the aggregation chamber had considerable influence on cluster aggregation process. At certain critical pressure, the presence of oxygen led to the raise of deposition rate and cluster size. Resulting clusters were composed mostly of tungsten trioxide. The oxygen pressure higher than critical led to the target poisoning and the decrease in the sputtering rate. Critical oxygen pressure decreased with increasing argon pressure, suggesting that cluster aggregation process was influenced by atomic oxygen species (namely, O"− ion) generated by oxygen–argon collisions in the magnetron plasma. - Highlights: • Formation of tungsten and tungsten oxide clusters was observed. • Two modes of cluster aggregation in pure argon atmosphere were found. • Dependence of cluster deposition speed and size on oxygen admixture was observed. • Changes of dependence on oxygen with changing argon pressure were described.

Inzicht in het presteren van de executieketen : Ontwikkeling van een monitor voor het meten van Kritieke Prestatie Indicatoren in de Executieketen

NARCIS (Netherlands)

Braak, S.W. van den; Netten, C.P.M.; Witzenburg, R. van

2013-01-01

Dit zijn de voorlopige resultaten van het ontwikkelprojcet Monitor Kritieke Prestatie Indicatoren Executieketen. Het structureel meten van de vastgestelde Kritieke Prestatie Indicatoren (KPI's) behelst het periodiek verzamelen, bewerken en presenteren van grote hoeveelheden data van verschillende

Clustering of housing and household patterns using 2011 population census

CSIR Research Space (South Africa)

Dudeni-Tlhone, N

2013-11-01

Full Text Available the clusters to measure the effects of urban growth boundaries on land development patterns. Vickers and Rees (2007) clustered the 2001 census data from the UK National Statistics Office to provide area classifications that could be distributed by the Office... of National Statistics via their website. Cluster analysis is also commonly applied inter- nationally to land-use data for many different types of studies, including: to derive landscape ty- pologies (Van Eetvelde and Antrop, 2009), to differentiate between...

Vergelijking van vangsten van een 12 m pulskor met een conventionele wekkerboomkor

NARCIS (Netherlands)

Marlen, van B.; Ybema, M.S.; Kraayenoord, A.; Vries, de M.; Rink, G.J.

2005-01-01

In het kader van de ontwikkeling van een pulskor als alternatief voor de conventionele boomkor met wekkerkettingen werd in nov-dec 2004 en jan 2005 onderzoek uitgevoerd op het visserij-onderzoekingsvaartuig “Tridens” naar de vangstverschillen van beide visserijtechnieken en de overleving van door

Het gebruik van antropometrische gegevens bij het opstellen van normen voor kantoorstoelen

NARCIS (Netherlands)

Groot, M.D. de; Voorbij, A.I.M.; Molenbroek, J.F.M.

2003-01-01

De fysieke belasting van werknemers is bij het invoeren van de personal computer veranderd. De werkplekken zijn zitplekken geworden. Het aantal gebruikers van kantoorstoelen is daarmee enorm toegenomen. Achter een monitor zitten mensen vaak lang achter elkaar in dezelfde houding, wat in weerwil van

De verleidelijkheid van het grote gebaar : Het werk van Dogma

NARCIS (Netherlands)

Teerds, P.J.

2013-01-01

In vier portacabins op het parkeerterrein van de Delftse Faculteit Bouwkunde is nog tot volgende week de tentoonstelling 11+1 projects te zien, een overzichtstentoonstelling van het intrigerende werk van het Brusselse bureau Dogma. Met de tentoonstelling zet de faculteit na de brand in 2008 weer een

De afschaffing van de bezwaarfase bij boetebesluiten van de ACM

NARCIS (Netherlands)

Jans, J.H.; Outhuijse, A.

Per 1 maart 2013 ontstaat door samenvoeging van de NMa, de OPTA en de Consumentenautoriteit, de Autoriteit Consument en Markt. Om de ACM slagvaardig te laten functioneren, wordt voorgesteld het handhavingsinstrumentarium m.b.t. het markttoezicht van de ACM te vereenvoudigen. Eén van de voorstellen

Implementatie van de Surviving Sepsis Campaign bundels : Monitoring van ervaringen

NARCIS (Netherlands)

Lilian Vloet; J. Schouten; N. Stevens; A. Rensen; A. Willems; F. Zeegers

2011-01-01

Sepsis komt vaak voor in ziekenhuizen. Ernstige sepsis is verantwoordelijk voor 10 - 20% van alle Intensive Care (IC) opnames en is de belangrijkste doodsoorzaak op niet-cardiale IC?s. De gemiddelde mortaliteit van volwassenen met ernstige sepsis op de IC is 33% en van volwassenen met septische

Supersonic molecular beam electric resonance spectroscopy and van der Waals molecules

International Nuclear Information System (INIS)