3,366 research outputs found

    The relaxation dynamics of a simple glass former confined in a pore

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    We use molecular dynamics computer simulations to investigate the relaxation dynamics of a binary Lennard-Jones liquid confined in a narrow pore. We find that the average dynamics is strongly influenced by the confinement in that time correlation functions are much more stretched than in the bulk. By investigating the dynamics of the particles as a function of their distance from the wall, we can show that this stretching is due to a strong dependence of the relaxation time on this distance, i.e. that the dynamics is spatially very heterogeneous. In particular we find that the typical relaxation time of the particles close to the wall is orders of magnitude larger than the one of particles in the center of the pore.Comment: 9 pages of Latex, 4 figure

    Graphene Oxide alpha Bi2O3 Composites for Visible Light Photocatalysis, Chemical Catalysis and Solar Energy Conversion

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    The growing challenges of environmental purification by solar photocatalysis, precious metal free catalysis and photocurrent generation in photovoltaic cells are receiving the utmost global attention. Here we demonstrate the one pot green chemical synthesis of a new stable heterostructured, eco friendly, multifunctional micro composite consisting of amp; 945; Bi2O3 micro needles intercalated with anchored graphene oxide GO micro sheets 1.0 wt for the above mentioned applications in a large economical scale. The bare amp; 945; Bi2O3 micro needles display twice as better photocatalytic activities than commercial TiO2 Degussa P25 while the GO hybridized composite exhibit 4 6 times enhanced photocatalytic activities than neat TiO2 photocatalyst in the degradation of colored aromatic organic dyes crystal violet and rhodamine 6G under visible light irradiation 300 W tungsten lamp . The highly efficient activity is associated with the strong surface adsorption ability of GO for aromatic dye molecules, the high carrier acceptability and efficient electron hole pair separation in Bi2O3 by individual adjoining GO sheets. Introduction of Ag nanoparticles 2.0 wt further enhances the photocatalytic performance of the composite over 8 folds due to a plasmon induced electron transfer process from Ag nanoparticles via GO sheets into the conduction band of Bi2O3. The new composites are also catalytically active. They catalyze the reduction of 4 nitrophenol to 4 aminophenol in presence of borohydride ions. Photoanodes assembled from GO amp; 945; Bi2O3 and Ag GO amp; 945; Bi2O3 composites display an improved photocurrent response power conversion efficiency 20 higher over those prepared without GO in dye sensitized solar cells DSSCs

    Isotope shift calculations for atoms with one valence electron

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    This work presents a method for the ab initio calculation of isotope shift in atoms and ions with one valence electron above closed shells. As a zero approximation we use relativistic Hartree-Fock and then calculate correlation corrections. The main motivation for developing the method comes from the need to analyse whether different isotope abundances in early universe can contribute to the observed anomalies in quasar absorption spectra. The current best explanation for these anomalies is the assumption that the fine structure constant, alpha, was smaller at early epoch. We test the isotope shift method by comparing the calculated and experimental isotope shift for the alkali and alkali-like atoms Na, MgII, K, CaII and BaII. The agreement is found to be good. We then calculate the isotope shift for some astronomically relevant transitions in SiII and SiIV, MgII, ZnII and GeII.Comment: 11 page

    A Wire-Based Methodology to Analyse the Nanometric Resolution of an RF Cavity BPM

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    Resonant Cavity Beam Position Monitors (RF-BPMs) are diagnostic instruments capable of achieving beam position resolutions down to the nanometre scale. To date, their nanometric resolution capabilities have been predicted by simulation and verified through beam-based measurements with particle beams. In the frame of the PACMAN project at CERN, an innovative methodology has been developed to directly observe signal variations corresponding to nanometric displacements of the BPM cavity with respect to a conductive stretched wire. The cavity BPM of this R&D study operates at the TM110 dipole mode frequency of 15GHz. The concepts and details of the RF stretched wire BPM testbench to achieve the best resolution results are presented, along with the required control hardware and software

    Short Musculoskeletal Function Assessment:normative data of the Dutch population

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    The Short Musculoskeletal Function Assessment (SMFA) is widely used in both research and clinical practice. Despite its frequent use, normative data of the SMFA have remained limited. Aim of this study was to gather normative data for the Dutch SMFA (SMFA-NL). The SMFA-NL consists of two indices (function index and bother index) and four subscales (upper extremity dysfunction, lower extremity dysfunction, mental and emotional problems, and problems with daily activities). A total of 900 patients were invited to fill in the SMFA-NL. Six age groups (18-24, 25-34, 35-44, 45-54, 55-64, and 65-75 years) were constructed. Analysis of variance, t tests, and regression analyses were used to assess age and gender effects. The response rate was 97 %. There was a significant difference between men and women in scores on all indices and subscales (range p <0.001 to p = 0.002), except for the upper extremity dysfunction subscale (p = 0.06). A significant interaction effect was found between gender and age for the upper extremity dysfunction subscale; a larger decrease in score with increasing age was observed for women, compared with men. Significant differences were found between age groups for the bother index (p <0.001), lower extremity dysfunction subscale (p = 0.001), and the problems with daily activities subscale (p = 0.002). Significant differences in SMFA-NL scores were found between men and women and between different age groups. These SMFA-NL normative data provide an opportunity of benchmarking health status of participants with musculoskeletal disorders or injuries against their age- and gender-matched peers in the Dutch population

    Cross-cultural adaptation of the Dutch Short Musculoskeletal Function Assessment questionnaire (SMFA-NL):Internal consistency, validity, repeatability and responsiveness

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    The purpose of this study was to translate and culturally adapt the Dutch version of the Short Musculoskeletal Function Assessment questionnaire (SMFA-NL) and to investigate the internal consistency, validity, repeatability and responsiveness of the translated version. The original SMFA was first translated and culturally adapted from English into Dutch according to a standardised procedure and subsequently tested for clinimetric quality. The study population consisted of 162 patients treated for various musculoskeletal injuries or disorders at the departments of Orthopedics and Traumatology. All respondents filled in the SMFA-NL and the SF-36 and a region-specific questionnaire. To determine repeatability, 87 respondents filled in the SMFA-NL for a second time after a time interval of three to four weeks. To determine responsiveness, 29 respondents who were treated for their injury within three months before the first assessment filled in the SMFA-NL for a second time after two to three months. The following analyses were performed to evaluate clinimetric quality of the SMFA-NL: factor analysis and Cronbach's alpha (internal consistency), floor and ceiling effects, Spearman's Rho (construct validity), intraclass correlation coefficients and the Bland & Altman method (repeatability), and standardised response means (SRM) (responsiveness). Factor analysis demonstrated four subscales of the SMFA-NL. Both the newly identified subscales of the SMFA-NL and the conventional subscales of the SMFA showed good internal consistency. No floor and some ceiling effects were found. Construct validity was good, as high correlations were found between the subscales of the SMFA-NL and the respective subscales of the SF-36 and the region-specific questionnaires. Repeatability of the SMFA-NL subscales was high, with no systematic bias between first and second assessment. Responsiveness of the SMFA-NL was moderate, as small to moderate SRMs were found. We successfully translated and culturally adapted a Dutch version of the Short Musculoskeletal Function Assessment questionnaire (SFMA-NL). This study shows that the SMFA-NL is a valid, reliable and moderately responsive method for the assessment of functional status of patients who have a broad range of musculoskeletal disorders. Furthermore, it will allow for comparison between different patient groups as well as for cross-cultural comparisons. (C) 2011 Elsevier Ltd. All rights reserved

    Decay-assisted collinear resonance ionization spectroscopy: Application to neutron-deficient francium

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    This paper reports on the hyperfine-structure and radioactive-decay studies of the neutron-deficient francium isotopes 202−206^{202-206}Fr performed with the Collinear Resonance Ionization Spectroscopy (CRIS) experiment at the ISOLDE facility, CERN. The high resolution innate to collinear laser spectroscopy is combined with the high efficiency of ion detection to provide a highly-sensitive technique to probe the hyperfine structure of exotic isotopes. The technique of decay-assisted laser spectroscopy is presented, whereby the isomeric ion beam is deflected to a decay spectroscopy station for alpha-decay tagging of the hyperfine components. Here, we present the first hyperfine-structure measurements of the neutron-deficient francium isotopes 202−206^{202-206}Fr, in addition to the identification of the low-lying states of 202,204^{202,204}Fr performed at the CRIS experiment.Comment: Accepted for publication with Physical Review

    What is the long-term clinical outcome after fragility fractures of the pelvis? - A CT-based cross-sectional study

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    Background: Recently, Rommens and Hoffman introduced a CT-based classification system for fragility fractures of the pelvis (FFP). Although fracture characteristics have been described, the relationship with clinical outcome is lacking. The purpose of this study was to get insight into the type of treatment and subsequent clinical outcome after all types of FFP. Methods: A cross-sectional cohort study was performed including all elderly patients (≄ 65 years) with a CT-diagnosed FFP, between 2007-2019 in two level 1 trauma centers. Data regarding treatment, mortality and clinical outcome was gathered from the electronic patient files. Patients were asked to complete patient-reported outcome measures (PROMs) regarding physical functioning (SMFA) and quality of life (EQ-5D). Additionally, a standardized multidisciplinary treatment algorithm was constructed. Results: A total of 187 patients were diagnosed with an FFP of whom 117 patients were available for follow-up analysis and 58 patients responded. FFP type I was most common (60%), followed by type II (27%), type III (8%) and type IV (5%). Almost all injuries were treated non-operatively (98%). Mobility at six weeks ranged from 50% (type III) to 80% type II). Mortality at 1 year was respectively 16% (type I and II), 47% (type III) and 13% (type IV). Physical functioning (SMFA function index) ranged from 62 (type III and IV) to 69 (type II) and was significantly decreased (P=<0.001) compared to the age-matched general population. Quality of life was also significantly decreased, ranging from 0.26 (type III) to 0.69 (type IV). Conclusions: FFP type I and II are most common. Treatment is mainly non-operative, resulting in good mobility after six weeks, especially for patients with FFP type I and II. Mortality rates at one year were substantial in all patients. Physical functioning and quality of life was about 20-30% decreased compared to the general population

    Laser spectroscopy of francium isotopes at the borders of the region of reflection asymmetry

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    The magnetic dipole moments and changes in mean-square charge radii of the neutron-rich 218m,219,229,231Fr^{218m,219,229,231}\text{Fr} isotopes were measured with the newly-installed Collinear Resonance Ionization Spectroscopy (CRIS) beam line at ISOLDE, CERN, probing the 7s 2S1/27s~^{2}S_{1/2} to 8p 2P3/28p~^{2}P_{3/2} atomic transition. The ή⟹r2⟩A,221\delta\langle r^{2}\rangle^{A,221} values for 218m,219Fr^{218m,219}\text{Fr} and 229,231Fr^{229,231}\text{Fr} follow the observed increasing slope of the charge radii beyond N = 126N~=~126. The charge radii odd-even staggering in this neutron-rich region is discussed, showing that 220Fr^{220}\text{Fr} has a weakly inverted odd-even staggering while 228Fr^{228}\text{Fr} has normal staggering. This suggests that both isotopes reside at the borders of a region of inverted staggering, which has been associated with reflection-asymmetric shapes. The g(219Fr)=+0.69(1)g(^{219}\text{Fr}) = +0.69(1) value supports a π1h9/2\pi 1h_{9/2} shell model configuration for the ground state. The g(229,231Fr)g(^{229,231}\text{Fr}) values support the tentative Iπ(229,231Fr)=(1/2+)I^{\pi}(^{229,231}\text{Fr}) = (1/2^{+}) spin, and point to a πs1/2−1\pi s_{1/2}^{-1} intruder ground state configuration.Comment: Accepted for publication with Physical Review
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