Support for Expert Estimations in Transportation Projects

This paper deals with risk analysis as a part of the financial assessment of transportation projects. Two approaches to risk assessment are discussed. A risk can be evaluated either directly in terms of the probabilistic distribution of the assessment criterion; or an indirect determination of the risk can be applied without constructing the probability distribution, but by determining the characteristic features of the project.

Absolute rate coefficients for photorecombination and electron-impact ionization of magnesium-like iron ions from measurements at a heavy-ion storage ring

Rate coefficients for photorecombination (PR) and cross sections for electron-impact ionization (EII) of Fe$^{14+}$ forming Fe$^{13+}$ and Fe$^{15+}$, respectively, have been measured by employing the electron-ion merged-beams technique at a heavy-ion storage ring. Rate coefficients for PR and EII of Fe$^{14+}$ ions in a plasma are derived from the experimental measurements. Simple parametrizations of the experimentally derived plasma rate coefficients are provided for use in the modeling of photoionized and collisionally ionized plasmas. In the temperature ranges where Fe$^{14+}$ is expected to form in such plasmas the latest theoretical rate coefficients of Altun et al. [Astron. Astrophys. 474, 1051 (2007)] for PR and of Dere [Astron. Astrophys. 466, 771 (2007)] for EII agree with the experimental results to within the experimental uncertainties. Common features in the PR and EII resonance structures are identified and discussed.Comment: 12 pages, 6 figures, 3 tables, submitted for publication to Physical Review

Absolute rate coefficients for photorecombination of berylliumlike and boronlike silicon ions

We report measured rate coefficients for electron-ion recombination for Si10+ forming Si9+ and for Si9+ forming Si8+, respectively. The measurements were performed using the electron-ion merged-beams technique at a heavy-ion storage ring. Electron-ion collision energies ranged from 0 to 50 eV for Si9+ and from 0 to 2000 eV for Si10+, thus, extending previous measurements for Si10+ [Orban et al. 2010, Astrophys. J. 721, 1603] to much higher energies. Experimentally derived rate coefficients for the recombination of Si9+ and Si10+ ions in a plasma are presented along with simple parameterizations. These rate coefficients are useful for the modeling of the charge balance of silicon in photoionized plasmas (Si9+ and Si10+) and in collisionally ionized plasmas (Si10+ only). In the corresponding temperature ranges, the experimentally derived rate coefficients agree with the latest corresponding theoretical results within the experimental uncertainties.Comment: 17 pages, 7 figures, 3 tables, 66 references, submitted to the J. Phys. B special issue on atomic and molecular data for astrophysicist

Energy-sensitive imaging detector applied to the dissociative recombination of D2H+

We report on an energy-sensitive imaging detector for studying the fragmentation of polyatomic molecules in the dissociative recombination of fast molecular ions with electrons. The system is based on a large area (10 cm x 10 cm) position-sensitive, double-sided Si-strip detector with 128 horizontal and 128 vertical strips, whose pulse height information is read out individually. The setup allows to uniquely identify fragment masses and is thus capable of measuring branching ratios between different fragmentation channels, kinetic energy releases, as well as breakup geometries, as a function of the relative ion-electron energy. The properties of the detection system, which has been installed at the TSR storage ring facility of the Max-Planck Institute for Nuclear Physics in Heidelberg, is illustrated by an investigation of the dissociative recombination of the deuterated triatomic hydrogen cation D2H+. A huge isotope effect is observed when comparing the relative branching ratio between the D2+H and the HD+D channel; the ratio 2B(D2+H)/B(HD+D), which is measured to be 1.27 +/- 0.05 at relative electron-ion energies around 0 eV, is found to increase to 3.7 +/- 0.5 at ~5 eV.Comment: 11 pages, 12 figures, submitted to Physical Review

The Reflection Kinesiology Analysis Of Cross Country Skiing – Classical Technique Diagonal Stride And Herring Bone

Studie přináší srovnání vybraných koordinačních parametrů při dvou způsobech běhu na lyžích. Díky tvarové podobnosti průběhu pohybu byly sledovány: běh na lyžích klasickou technikou dvoudobým střídavým a oboustranným odvratem („stromečkem“). Komparativní analýza se soustředila na odraz, který je rozhodující fází pro propulzi. Monitorována byla aktivace vybraných svalů dolních končetin ve fázi odrazu během sledovaných aktivit za použití povrchové polyelektromyografie se synchronizovaným akcelerometrem pro určení rozhraní mezi jednotlivými pracovními cykly.Získaná data byla zpracována v SW MegaWin a MatLab, analyzována progresivní trojúhelníkovou metodou a porovnávána statistikou ANOVA1. Soubor sestával ze sedmi reprezentantů ČR v běhu na lyžích. Ze statistických výsledků lze usuzovat na vysokou laterální intralokomoční podobnost klasické techniky (DS) i stromečku (HB) u všech probandů.Teoretický přínos práce spatřujeme v objektivizaci přítomnosti (DS) nebo absence (HB) fáze skluzu, která se v průběhu fylogeneze lokomoce živočišných druhů směřujících k rodu Homo nevyskytuje. Klasická technika se na rozdíl od výstupu stromečkem vyznačuje fází skluzu, tím se vyčleňuje z přirozené lokomoce suchozemských obratlovců a člověk se jí musí učit.This study examines the comparison of the representative coordination parameters during cross-country skiing – classic technique-diagonal stride and herringbone. The kick was also assessed in the comparative analysis because the kick is the determinative for propulsion. The activation of selected muscles on the legs during skiing was monitored with surface electromyography. To pinpoint the boundary between two following movement cycles, we used the synchronized accelerometer. The data was processed by SW Mega Win and MatLab and analysed by the progressive triangle method and compared by ANOVA1. The monitored group was created using seven men who were all members of Czech Cross-Country Ski Team. Base on the data, we may presume a high level of the lateral similarity of cross-country skiing classic technique and herringbone. The base of significant differences in muscle activation was found in the glide phase of the movement cycle. The glide phase is very important during the diagonal stride cycle while the herringbone step is not assisted by any gliding. During human phylogenies, no animal uses any gliding so the gliding by the diagonal stride is not natural and has to be learn it

Cryogenic micro-calorimeters for mass spectrometric identification of neutral molecules and molecular fragments

We have systematically investigated the energy resolution of a magnetic micro-calorimeter (MMC) for atomic and molecular projectiles at impact energies ranging from $E\approx13$ to 150 keV. For atoms we obtained absolute energy resolutions down to $\Delta E \approx 120$ eV and relative energy resolutions down to $\Delta E/E\approx10^{-3}$. We also studied in detail the MMC energy-response function to molecular projectiles of up to mass 56 u. We have demonstrated the capability of identifying neutral fragmentation products of these molecules by calorimetric mass spectrometry. We have modeled the MMC energy-response function for molecular projectiles and conclude that backscattering is the dominant source of the energy spread at the impact energies investigated. We have successfully demonstrated the use of a detector absorber coating to suppress such spreads. We briefly outline the use of MMC detectors in experiments on gas-phase collision reactions with neutral products. Our findings are of general interest for mass spectrometric techniques, particularly for those desiring to make neutral-particle mass measurements

Semiconductor Bloch equation analysis of optical Stark and Bloch-Siegert shifts in monolayers WSe2_2 and MoS2_2

We report on the theoretical and experimental investigation of valley-selective optical Stark and Bloch-Siegert shifts of exciton resonances in monolayers WSe$_2$ and MoS$_2$ induced by strong circularly polarized nonresonant optical fields. We predict and observe transient shifts of both 1sA and 1sB exciton transitions in the linear interaction regime. The theoretical description is based on semiconductor Bloch equations. The solutions of the equations are obtained with a modified perturbation technique, which takes into account many-body Coulomb interaction effects. These solutions allow to explain the polarization dependence of the shifts and calculate their values analytically. We found experimentally the limits of the applicability of the theoretical description by observing the transient exciton spectra change due to many-body effects at high field amplitudes of the driving wave.Comment: 20 pages, 9 figures, this manuscript is related to the "Giant valley-selective Stark and Bloch-Siegert shifts of exciton resonances in WSe$_2$ and MoS$_2$ monolayers" manuscrip

Dissociative recombination measurements of HCl+ using an ion storage ring

We have measured dissociative recombination of HCl+ with electrons using a merged beams configuration at the heavy-ion storage ring TSR located at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. We present the measured absolute merged beams recombination rate coefficient for collision energies from 0 to 4.5 eV. We have also developed a new method for deriving the cross section from the measurements. Our approach does not suffer from approximations made by previously used methods. The cross section was transformed to a plasma rate coefficient for the electron temperature range from T=10 to 5000 K. We show that the previously used HCl+ DR data underestimate the plasma rate coefficient by a factor of 1.5 at T=10 K and overestimate it by a factor of 3.0 at T=300 K. We also find that the new data may partly explain existing discrepancies between observed abundances of chlorine-bearing molecules and their astrochemical models.Comment: Accepted for publication in ApJ (July 7, 2013