Search results for "methods"
showing 10 items of 4526 documents
Calibration of the RPC charge readout in the ARGO-YBJ experiment
2012
""The charge readout of Resistive Plate Chambers (RPCs) is implemented in the ARGO-YBJ experiment to measure the charged particle density of the shower front up to 10^4\\\/m^2, enabling the study of the primary cosmic rays with energies in the ''knee'' region. As the first time for RPCs being used this way, a telescope with RPCs and scintillation detectors is setup to calibrate the number of charged particles hitting a RPC versus its charge readout. Air shower particles are taken as the calibration beam. The telescope was tested at sea level and then moved to the ARGO-YBJ site for coincident operation with the ARGO-YBJ experiment. The charge readout shows good linearity with the particle de…
Time calibration of the ANTARES neutrino telescope
2011
The ANTARES deep-sea neutrino telescope comprises a three-dimensional array of photomultipliers to detect the Cherenkov light induced by upgoing relativistic charged particles originating from neutrino interactions in the vicinity of the detector. The large scattering length of light in the deep sea facilitates an angular resolution of a few tenths of a degree for neutrino energies exceeding 10 TeV. In order to achieve this optimal performance, the time calibration procedures should ensure a relative time calibration between the photomultipliers at the level of ~1 ns. The methods developed to attain this level of precision are described.
ANTARES: The first undersea neutrino telescope
2011
The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design, the construction and the installation of the telescope in the deep sea, offshore from Toulon in France. An illustration of the detector performance is given. © 2011 Elsevier B.V. All rights reserved.
The ANTARES telescope neutrino alert system
2012
The ANTARES telescope has the capability to detect neutrinos produced in astrophysical transient sources. Potential sources include gamma-ray bursts, core collapse supernovae, and flaring active galactic nuclei. To enhance the sensitivity of ANTARES to such sources, a new detection method based on coincident observations of neutrinos and optical signals has been developed. A fast online muon track reconstruction is used to trigger a network of small automatic optical telescopes. Such alerts are generated for special events, such as two or more neutrinos, coincident in time and direction, or single neutrinos of very high energy.
Design of compensated multiport waveguide junctions considering mechanization effects
2015
Abstract A new tool for the rigorous and efficient design of compensated multiport waveguide junctions, considering the mechanization effects due to low-cost manufacture techniques, is presented. Several new designs for a great variety of key components, present in modern microwave and millimetre-wave equipment, are proposed taking into account the introduction of rounded corners in the rectangular waveguide access ports. The new implemented tool permits to control and compensate for the potential degradation of the wide-band performance of such components prior to their fabrication, thus achieving an optimal design. All the presented results have been successfully validated by comparing th…
A methodology for developing evidence-based optimization models in humanitarian logistics
2022
AbstractThe growing need for humanitarian assistance has inspired an increasing amount of academic publications in the field of humanitarian logistics. Over the past two decades, the humanitarian logistics literature has developed a powerful toolbox of standardized problem formulations to address problems ranging from distribution to scheduling or locations planning. At the same time, the humanitarian field is quickly evolving, and problem formulations heavily rely on the context, leading to calls for more evidence-based research. While mixed methods research designs provide a promising avenue to embed research in the reality of the field, there is a lack of rigorous mixed methods research …
Theoretical study of the effect of substituent and backbone conformation on the electronic properties of symmetrically substituted poly(di‐n‐alkylsil…
1994
We present the results of ab initio 3‐21G∗ geometry optimizations and valence effective Hamiltonian (VEH) band structure calculations aimed at determining the evolution of the geometric and electronic (ionization potential, electron affinities, and band gaps) properties of all‐trans poly(dimethylsilane), poly(diethylsilane), poly(di‐n‐propylsilane), and poly(di‐n‐butylsilane) when increasing the size of the alkyl group. In the latter polymer, we have also studied the 7/3 conformation, in order to analyze the effect of the backbone conformation on the geometric and electronic structure. The VEH ionization potentials of all‐trans poly(di‐n‐alkylsilanes) are almost equal, and as experimental p…
Comparison of Numerical Methods in the Contrast Imaging Problem in NMR
2013
International audience; In this article, the contrast imaging problem in nuclear magnetic resonance is modeled as a Mayer problem in optimal control. A first synthesis of locally optimal solutions is given in the single-input case using geometric methods based on Pontryagin's maximum principle. We then compare these results using direct methods and a moment-based approach, and make a first step towards global optimality. Finally, some preliminary results are given in the bi-input case.
Evaluating a hierarchical approach to landscape level harvest scheduling
2018
Forest planning at the landscape level has the potential to become a large intractable problem. In Finland, Metsähallitus (the state enterprise that manages federally owned land) creates strategic plans to determine the appropriate harvest level. While these plans are feasible, they are not implementable in practice as the harvests are scattered temporally and spatially. Requiring that harvests be organized both temporally and spatially for practical implementation can result in an intractable problem. Through a hierarchical approach, the problem can be organized into steps in which the intractable problem is broken down into smaller easily solvable parts. As an approximation technique, the…
Beobachtungen nach einer neuen optischen Methode: ein Beitrag zur Experimental-Physik
1864
Inhalt: Princip der Beobachtungs-Methode... 2 Specielle Beschreibung des Apparates... 8 Bemerkungen über den Gebrauch und die Adjustirung... 13 Schlieren in Gläsern ... 16 Beobachtungen mittels des Schlieren-Apparates... 18 Veränderung durchsichtiger Körper durch Temperatur und Druck... 19 Diffusionsbewegungen... 21 Untersuchung der Flammen... 23 Beugungsphänomene... 26 Sichtbarmachung der Schallwellen... 27 Beobachtungen über den electrischen Funken... 29 Der Inductionsfunken... 35 Der Flaschenfunken... 42 Schlussbemerkungen... 49