828 research outputs found
The Beam Conditions Monitor of the LHCb Experiment
The LHCb experiment at the European Organization for Nuclear Research (CERN)
is dedicated to precision measurements of CP violation and rare decays of B
hadrons. Its most sensitive components are protected by means of a Beam
Conditions Monitor (BCM), based on polycrystalline CVD diamond sensors. Its
configuration, operation and decision logics to issue or remove the beam permit
signal for the Large Hadron Collider (LHC) are described in this paper.Comment: Index Terms: Accelerator measurement systems, CVD, Diamond, Radiation
detector
Маркшейдерська школа Національного гірничого університету
Викладена історія створення та розвитку маркшейдерської школи в НГУ протягом 110 років.Изложена история создания и развития маркшейдерской школы в НГУ в течение 110 лет.History of creation and development ofsurveyor school is expounded in NMU during 110 years
Onchocerciasis in the Americas: from arrival to (near) elimination
Onchocerciasis (river blindness) is a blinding parasitic disease that threatens the health of approximately 120 million people worldwide. While 99% of the population at-risk for infection from onchocerciasis live in Africa, some 500,000 people in the Americas are also threatened by infection. A relatively recent arrival to the western hemisphere, onchocerciasis was brought to the New World through the slave trade and spread through migration. The centuries since its arrival have seen advances in diagnosing, mapping and treating the disease. Once endemic to six countries in the Americas (Brazil, Colombia, Ecuador, Guatemala, Mexico and Venezuela), onchocerciasis is on track for interruption of transmission in the Americas by 2012, in line with Pan American Health Organization resolution CD48.R12. The success of this public health program is due to a robust public-private partnership involving national governments, local communities, donor organizations, intergovernmental bodies, academic institutions, non-profit organizations and the pharmaceutical industry. The lessons learned through the efforts in the Americas are in turn informing the program to control and eliminate onchocerciasis in Africa. However, continued support and investment are needed for program implementation and post-treatment surveillance to protect the gains to-date and ensure complete elimination is achieved and treatment can be safely stopped within all 13 regional foci
Luminescence and formation of alkali-halide ionic excimers in solid Ne and Ar
Transitions from ionic states A²⁺X– of alkalihalides CsF, CsCl and RbF isolated in solid Ne and Ar films recorded under pulsed e-beam excitation are studied. The B(²∑₁/₂)-X(²∑₁/₂) and C(²П₃/₂)-A(²П₃/₂) luminescence bands of Cs2+F– (196.5 nm, 227 nm), Cs²⁺Cl– (220.1 nm, 249.2 nm) and Rb²⁺F– (136 nm) in Ne, and a weakerB–X emission of Cs²⁺F– (211.2 nm) in Ar are identified. For CsF the depopulation of the A²⁺X– state is dominated by the radiative decay. A ratio of the recorded exciplex emission intensities of I(CsF)/I(CsCl)/I(RbF) = 20/5/1 reflects the luminescence efficiency and for RbF and CsCl a competitive emission channel due to predissociation in the A²⁺X⁻(B²∑₁/₂) state is observed. For these molecules an efficient formation of the state X*₂ is confirmed through recording the molecular D`(³П₂g)-A`(³П₂u) transition. A strong dependence of the luminescence intensities on the alkalihalide content reveals quenching at concentrations higher than 0.7%
Dynamics of viscous amphiphilic films supported by elastic solid substrates
The dynamics of amphiphilic films deposited on a solid surface is analyzed
for the case when shear oscillations of the solid surface are excited. The two
cases of surface- and bulk shear waves are studied with film exposed to gas or
to a liquid. By solving the corresponding dispersion equation and the wave
equation while maintaining the energy balance we are able to connect the
surface density and the shear viscocity of a fluid amphiphilic overlayer with
experimentally accessible damping coefficients, phase velocity, dissipation
factor and resonant frequency shifts of shear waves.Comment: 19 pages, latex, 3 figures in eps-forma
Surface Oscillations in Overdense Plasmas Irradiated by Ultrashort Laser Pulses
The generation of electron surface oscillations in overdense plasmas
irradiated at normal incidence by an intense laser pulse is investigated.
Two-dimensional (2D) particle-in-cell simulations show a transition from a
planar, electrostatic oscillation at , with the laser
frequency, to a 2D electromagnetic oscillation at frequency and
wavevector . A new electron parametric instability, involving the
decay of a 1D electrostatic oscillation into two surface waves, is introduced
to explain the basic features of the 2D oscillations. This effect leads to the
rippling of the plasma surface within a few laser cycles, and is likely to have
a strong impact on laser interaction with solid targets.Comment: 9 pages (LaTeX, Revtex4), 4 GIF color figures, accepted for
publication in Phys. Rev. Let
Upgraded sublimation energy determination procedure for icy films
“NOTICE: this is the author’s version of a work that was accepted for publication in . Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in VACUUM, [VOL 86, ISSUE 12, (2012-06)] DOI10.1016/j.vacuum.2012.05.010¨A method to determine the sublimation energy of a bulk ice in high vacuum systems, allowing other simultaneous analysis techniques, is presented. Variation in frequency of a quartz crystal microbalance, due to sublimating material, during a zeroth-order desorption consents to obtain this energy. CO 2 sublimation energy is obtained to check this method, its value is coherent with that reported in the literature. Our method permits to simplify the setup used so far by other authors, and to obtain relevant parameters for ices simultaneously. The procedure explained here corrects the temperature frequency dependence of the microbalance and the effect of contaminants by using a unique microbalance. © 2012 Elsevier Ltd. All rights reserved.This work was supported by the Ministerio de Educacion y Ciencia (Co-financed by FEDER funds) AYA 2004-05382 and AYA 2007-65899.Luna Molina, R.; Millán Verdú, C.; Domingo Beltran, M.; Santonja Moltó, MDC.; Satorre Aznar, MÁ. (2012). Upgraded sublimation energy determination procedure for icy films. Vacuum. 86(12):1969-1973. https://doi.org/10.1016/j.vacuum.2012.05.010S19691973861
Role of surface roughness in hard x-ray emission from femtosecond laser produced copper plasmas
The hard x-ray emission in the energy range of 30-300 keV from copper plasmas
produced by 100 fs, 806 nm laser pulses at intensities in the range of
10 W cm is investigated. We demonstrate that surface
roughness of the targets overrides the role of polarization state in the
coupling of light to the plasma. We further show that surface roughness has a
significant role in enhancing the x-ray emission in the above mentioned energy
range.Comment: 5 pages, 4 figures, to appear in Phys. Rev.
Mass movement deposits in the 3.6 Ma sediment record of Lake El'gygytgyn, Far East Russian Arctic
This paper focuses on the characterization and genesis of mass movement deposits (MMDs) in the Quater- nary and Pliocene sediments of Lake El’gygytgyn, Far East Russian Arctic. Three partly overlapping holes were drilled into the 320 m long sediment record at International Conti- nental Scientific Drilling Program (ICDP) Site 5011-1 in the lake basin, recovering the Quaternary almost completely, and the Pliocene down to 3.6 Ma with 52 % recovery. Mass move- ment deposits were investigated in all three cores, based on macroscopical core descriptions, radiographic images, high- resolution magnetic susceptibility and gamma-ray density. Five different types of MMDs were identified: turbidites, grain-flow deposits, debrites, slumps and slides. These are formed by transitional mass movement processes, and thus can be co-generic. An initial slope failure is thought to trans- form into a debris flow that deforms frontal sediments, partly disintegrates and dilutes into a turbidity flow. Turbidites are by far the most frequent MMD type in the lake center. They occur throughout the record in all pelagic sedimentary fa- cies, but they are thinner in facies formed during cold cli- mate conditions. All other MMDs, by contrast, incise exclu- sively the pelagic facies deposited during warm climates. In the 123 m thick Quaternary composite sediment record 230 mass movement events are identified, comprising 33% of the sediment length. Turbidites contribute 93 % of the num- ber of Quaternary MMDs, but only 35 % of their thickness. In the Pliocene sediments between 123 and 320 m, 181 ad- ditional mass movement deposits are identified, which con- stitute ⇠ 33 % of the recovered sediments. The mean recur- rence interval for MMDs is 11 and 5 ka in the Quaternary and Pliocene, respectively
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