9,154 research outputs found
Environmental test planning, selection and standardization aids available
Requirements for instrumentation, equipment, and methods to be used in conducting environmental tests on components intended for use by a wide variety of technical personnel of different educational backgrounds, experience, and interests is announced
Multi-hadron states in Lattice QCD spectroscopy
The ability to reliably measure the energy of an excited hadron in Lattice
QCD simulations hinges on the accurate determination of all lower-lying
energies in the same symmetry channel. These include not only single-particle
energies, but also the energies of multi-hadron states. This talk deals with
the determination of multi-hadron energies in Lattice QCD. The
group-theoretical derivation of lattice interpolating operators that couple
optimally to multi-hadron states is described. We briefly discuss recent
algorithmic developments which allow for the efficient implementation of these
operators in software, and present numerical results from the Hadron Spectrum
Collaboration.Comment: 5 pages, 3 figures, talk given at Hadron 2009, Tallahassee, Florida,
December 1, 200
Consultation with complementary medicine practitioners by individuals with chronic conditions: Characteristics and reasons for consultation in Australian clinical settings.
The duration and complexity of chronic conditions leads patients to consult complementary medicine (CM) practitioners, yet such care-seeking by this clinical population has not been thoroughly examined. This study describes characteristics and reasons for consultation amongst those with chronic conditions who consult CM practitioners. A cross-sectional study surveyed patients in clinics of 39 CM practitioners from the five most accessed CM professions in Australia (chiropractic, massage, osteopathy, acupuncture, naturopathy). Between November 2018 and March 2019, CM practitioners invited 15 consecutive adult patients (n = 585 invited) to a self-administered, hard-copy survey covering socio-demographics, chronic condition diagnoses, CM service utilisation and reasons for consulting the CM practitioner. In total, 199 surveys were returned, producing a final sample of n = 191. Chronic conditions were reported by 153 (80.1%) participants, who were most commonly female (82.4%), aged over 65 years (29.0%), married (55.9%), vocational/trade qualified (40.1%), employed (62.5%), reported financial manageability as not too bad (48.0%), held private health insurance generally (79.0%) and specifically for CM (71.1%). Some socio-demographic differences were found depending on the profession consulted. Most participants (75.0%) had attended five or more consultations with the CM practitioner. The reasons most commonly given by participants with chronic conditions for consulting the CM practitioner were This healthcare professional is supportive and compassionate (n = 136, 97.1%), I believe this type of healthcare is safe (n = 131, 95.6%), Improve general wellbeing and prevent future health problems (n = 125, 89.3%) and This type of healthcare gives me hope about my future health (n = 108, 85.7%). These findings suggest that individuals with chronic conditions may consult CM practitioners to address unmet well-being or quality of life needs and for compassionate support. The role CM practitioners fill for those with chronic conditions requires further exploration to develop optimal policy and services to manage the growing challenges chronic conditions present to health systems
Rotational Dynamics of Organic Cations in CH3NH3PbI3 Perovskite
Methylammonium lead iodide (CH3NH3PbI3) based solar cells have shown
impressive power conversion efficiencies of above 20%. However, the microscopic
mechanism of the high photovoltaic performance is yet to be fully understood.
Particularly, the dynamics of CH3NH3+ cations and their impact on relevant
processes such as charge recombination and exciton dissociation are still
poorly understood. Here, using elastic and quasi-elastic neutron scattering
techniques and group theoretical analysis, we studied rotational modes of the
CH3NH3+ cation in CH3NH3PbI3. Our results show that, in the cubic (T > 327K)
and tetragonal (165K < T < 327K) phases, the CH3NH3+ ions exhibit four-fold
rotational symmetry of the C-N axis (C4) along with three-fold rotation around
the C-N axis (C3), while in orthorhombic phase (T < 165K) only C3 rotation is
present. Around room temperature, the characteristic relaxation times for the
C4 rotation is found to be ps while for the C3 rotation ps. The -dependent
rotational relaxation times were fitted with Arrhenius equations to obtain
activation energies. Our data show a close correlation between the C4
rotational mode and the temperature dependent dielectric permittivity. Our
findings on the rotational dynamics of CH3NH3+ and the associated dipole have
important implications on understanding the low exciton binding energy and slow
charge recombination rate in CH3NH3PbI3 which are directly relevant for the
high solar cell performance
The excited hadron spectrum in lattice QCD using a new method of estimating quark propagation
Progress in determining the spectrum of excited baryons and mesons in lattice
QCD is described. Large sets of carefully-designed hadron operators have been
studied and their effectiveness in facilitating the extraction of excited-state
energies is demonstrated. A new method of stochastically estimating the
low-lying effects of quark propagation is proposed which will allow reliable
determinations of temporal correlations of single-hadron and multi-hadron
operators.Comment: 5 pages, 4 figures, talk given at Hadron 2009, Tallahassee, Florida,
December 1, 200
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Ultrahigh power and energy density in partially ordered lithium-ion cathode materials
The rapid market growth of rechargeable batteries requires electrode materials that combine high power and energy and are made from earth-abundant elements. Here we show that combining a partial spinel-like cation order and substantial lithium excess enables both dense and fast energy storage. Cation overstoichiometry and the resulting partial order is used to eliminate the phase transitions typical of ordered spinels and enable a larger practical capacity, while lithium excess is synergistically used with fluorine substitution to create a high lithium mobility. With this strategy, we achieved specific energies greater than 1,100 Wh kg–1 and discharge rates up to 20 A g–1. Remarkably, the cathode materials thus obtained from inexpensive manganese present a rare case wherein an excellent rate capability coexists with a reversible oxygen redox activity. Our work shows the potential for designing cathode materials in the vast space between fully ordered and disordered compounds
Capabilities and Choices: Do They Make Sen’se for Understanding Objective and Subjective Well-Being? An Empirical Test of Sen’s Capability Framework on German and British Panel Data
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