9,689 research outputs found

    The Electrostatic Ion Beam Trap : a mass spectrometer of infinite mass range

    Full text link
    We study the ions dynamics inside an Electrostatic Ion Beam Trap (EIBT) and show that the stability of the trapping is ruled by a Hill's equation. This unexpectedly demonstrates that an EIBT, in the reference frame of the ions works very similar to a quadrupole trap. The parallelism between these two kinds of traps is illustrated by comparing experimental and theoretical stability diagrams of the EIBT. The main difference with quadrupole traps is that the stability depends only on the ratio of the acceleration and trapping electrostatic potentials, not on the mass nor the charge of the ions. All kinds of ions can be trapped simultaneously and since parametric resonances are proportional to the square root of the charge/mass ratio the EIBT can be used as a mass spectrometer of infinite mass range

    Quantum Geometry Phenomenology: Angle and Semiclassical States

    Get PDF
    The phenomenology for the deep spatial geometry of loop quantum gravity is discussed. In the context of a simple model of an atom of space, it is shown how purely combinatorial structures can affect observations. The angle operator is used to develop a model of angular corrections to local, continuum flat-space 3-geometries. The physical effects involve neither breaking of local Lorentz invariance nor Planck scale suppression, but rather reply on only the combinatorics of SU(2) recouping theory. Bhabha scattering is discussed as an example of how the effects might be observationally accessible.Comment: 5 pages, slightly extended version of the contribution to the Loops'11 conference proceeding

    Computation of Electric Energy Exchange between two Power Systems

    Get PDF
    The expected energy exchange between cooperating systems is an important information supporting capacity expansion planning for electric power systems. A model based on engineering considerations and a program system on IBM/PC-XT or AT compatibles has been developed for the stochastic analysis of the electric energy exchange between two interconnected power systems. Data required for the analysis are expected generation and load in the individual systems, and interties data. This work has been carried out in the frame of the IIASA Contracted Study "Modeling of interconnected power systems"

    Spin-triplet paired phases inside ferromagnet induced by Hund's rule coupling and electronic correlations: Application to UGe2\mathrm{UGe}_2

    Full text link
    We discuss a mechanism of real-space spin-triplet pairing, alternative to that due to quantum paramagnon excitations, and demonstrate its applicability to UGe2\mathrm{UGe_2}. Both the Hund's rule ferromagnetic exchange and inter-electronic correlations contribute to the same extent to the equal-spin pairing, particularly in the regime in which the weak-coupling solution does not provide any. The theoretical results, obtained within the orbitally-degenerate Anderson lattice model, match excellently the observed phase diagram for UGe2\mathrm{UGe_2} with the coexistent ferromagnetic (FM1) and superconducting (A1A_1-type) phase. Additionally, weak A2A_2- and AA-type paired phases appear in very narrow regions near the metamaganetic (FM2 \rightarrow FM1) and FM1 \rightarrow paramagnetic first-order phase-transition borders, respectively. The values of magnetic moments in the FM2 and FM1 states are also reproduced correctly in a semiquantitative manner. The Hund's metal regime is also singled out as appearing near FM1-FM2 boundary

    Lived experiences of informal caregivers of people with chronic musculoskeletal pain: a systematic review and meta-ethnography

    Get PDF
    BACKGROUND: People with chronic pain often seek support from friends and family for everyday tasks. These individuals are termed informal caregivers. There remains uncertainty regarding the lived experiences of these people who care for individuals with chronic musculoskeletal pain. The aim of this paper is to synthase the evidence on the lived experiences of informal caregivers providing care to people with chronic musculoskeletal pain. METHODS: A systematic literature review was undertaken of published and unpublished literature databases including: EMBASE, MEDLINE, CINAHL, PubMed, the WHO International Clinical Trial Registry and ClinicalTrials.gov registry (to September 2019). Qualitative studies exploring the lived experiences of informal caregivers of people with chronic musculoskeletal pain were included. Data were synthesised using a meta-ethnography approach. Evidence was evaluated using the Critical Appraisal Skills Programme (CASP) qualitative appraisal tool. RESULTS: From 534 citations, 10 studies were eligible (360 participants: 171 informal caregivers of 189 care recipients). The evidence was moderate quality. Seven themes arose: the relationship of caregivers to healthcare professionals, role reversal with care recipients; acting the confidant to the care recipient; a constant burden in caregiving; legitimising care recipient’s condition; knowledge and skills to provide caregiving; and the perception of other family members and wider-society to the caregiver/care recipient dyad. CONCLUSIONS: The lived experiences of caregivers of people with chronic musculoskeletal pain is complex and dynamic. There is an inter-connected relationship between caregivers, care recipients and healthcare professionals. Exploring how these experiences can be modified to improve a caregiving dyad’s lived experience is now warranted

    Analysis of standing vertical jumps using a force platform

    Get PDF
    A force platform analysis of vertical jumping provides an engaging demonstration of the kinematics and dynamics of one-dimensional motion. The height of the jump may be calculated (1) from the flight time of the jump, (2) by applying the impulse–momentum theorem to the force–time curve, and (3) by applying the work–energy theorem to the force-displacement curve

    Shape in an Atom of Space: Exploring quantum geometry phenomenology

    Full text link
    A phenomenology for the deep spatial geometry of loop quantum gravity is introduced. In the context of a simple model, an atom of space, it is shown how purely combinatorial structures can affect observations. The angle operator is used to develop a model of angular corrections to local, continuum flat-space 3-geometries. The physical effects involve neither breaking of local Lorentz invariance nor Planck scale suppression, but rather reply on only the combinatorics of SU(2) recoupling. Bhabha scattering is discussed as an example of how the effects might be observationally accessible.Comment: 14 pages, 7 figures; v2 references adde
    corecore