3,351 research outputs found
Low-profile and wearable energy harvester based on plucked piezoelectric cantilevers
The Pizzicato Energy Harvester (EH) introduced the technique of frequency up-conversion to piezoelectric EHs wearable on the lateral side of the knee-joint. The operation principle is to pluck the piezoelectric bimorphs with plectra so that they produce electrical energy during the ensuing mechanical vibrations. The device presented in this work is, in some ways, an evolution of the earlier Pizzicato: it is a significantly more compact and lighter device; the central hub holds 16 piezoelectric bimorphs shaped as trapezoids, which permits a sleek design and potentially increased energy output for the same bimorph area. Plectra were formed by Photochemical Machining of a 100-ÎŒm-thick steel sheet. To avoid the risk of short-circuiting, the plectra were electrically passivated by sputtering a 100 nm layer of ZrO2. Bench tests with the steel plectra showed a very large energy generation. Polyimide plectra were also manufactured with a cutting plotter from a 125ÎŒm-thick film. Besides bench tests, a volunteer wore the device while walking on flat ground or climbing stairs, with a measured energy output of approximately 0.8 mJ per step. Whereas most of the tests were performed by the traditional method of discharging the rectified output from the EH onto a resistive load, tests were performed also with a circuit offering a stabilised 3.3 V supply. The circuit produced a stable 0.1 mA supply during running gait with kapton plectra
Thermodynamics of Multi-Component Fermi Vapors
We study the thermodynamical properties of Fermi vapors confined in a
harmonic external potential. In the case of the ideal Fermi gas, we compare
exact density profiles with their semiclassical approximation in the conditions
of recent experiments. Then, we consider the phase-separation of a
multi-component Fermi vapor. In particular, we analyze the phase-separation as
a function of temperature, number of particles and scattering length. Finally,
we discuss the effect of rotation on the stability and thermodynamics of the
trapped vapors.Comment: 15 pages, 5 figures, to be published in J. Phys. B (Atom. Mol.) as a
Special Issue Articl
Diagonal restrictions of -adic Eisenstein families
We compute the diagonal restriction of the first derivative with respect to the weight of a p-adic family of Hilbert modular Eisenstein series attached to a general (odd) character of the narrow class group of a real quadratic field, and express the Fourier coefficients of its ordinary projection in terms of the values of a distinguished rigid analytic cocycle in the sense of Darmon and Vonk (Duke Math J, to appear, 2020) at appropriate real quadratic points of Drinfeldâs p-adic upper half-plane. This can be viewed as the p-adic counterpart of a seminal calculation of Gross and Zagier (J Reine Angew Math 355:191â220, 1985, §7) which arose in their âanalytic proofâ of the factorisation of differences of singular moduli, and whose inspiration can be traced to Siegelâs proof of the rationality of the values at negative integers of the Dedekind zeta function of a totally real field. Our main identity enriches the dictionary between the classical theory of complex multiplication and its extension to real quadratic fields based on RM values of rigid meromorphic cocycles, and leads to an expression for the p-adic logarithms of GrossâStark units and StarkâHeegner points in terms of the first derivatives of certain twisted Rankin triple product p-adic L-functions
The M_BH-M_star relation of obscured AGNs at high redshift
We report the detection of broad Halpha emission in three X-ray selected
obscured AGNs at z=1-2. By exploiting the Halpha width and the intrinsic X-ray
luminosity, we estimate their black hole masses, which are in the range
0.1-3x10^9 Msun. By means of multi-band photometric data, we measure the
stellar mass of their host galaxy and, therefore, infer their M_BH/M_star
ratio. These are the first obscured AGNs at high-z, selected based on their
black hole accretion (i.e. on the basis of their X-ray luminosity), that can be
located on the M_BH-M_star relation at high-z. All of these obscured high-z
AGNs are fully consistent with the local M_BH-M_star relation. This result
conflicts with those for other samples of AGNs in the same redshift range,
whose M_BH/M_star ratio departs significantly from the value observed in local
galaxies. We suggest that the obscured AGNs in our sample are in an advanced
evolutionary stage, have already settled onto the local M_BH-M_star relation,
and whose nuclear activity has been temporarily revived by recent galaxy
interactions.Comment: 4 pages, 2 figures, accepted for publication in A&A Letters, slightly
revised discussion on SMG
Characterization of a novel HESX1 mutation in a pediatric case of septo-optic dysplasia
Septoâoptic dysplasia (SOD) is a rare condition for which the precise etiology is still unclear. Elucidating the genetic component of SOD is a difficult but necessary task for the future. We describe herein a novel HESX1 c.475C>T (p.R159W) mutation and demonstrate its potential pathogenicity in the development of this rare disease
The star formation rate cookbook at 1 < z < 3: Extinction-corrected relations for UV & [OII]{\lambda}3727 luminosities
We use a spectroscopic sample of 286 star-forming galaxies (SFGs) at 1<z<3
from the GMASS survey to study different star formation rate (SFR) estimators.
Infrared (IR) data are used to derive empirical calibrations to correct
ultraviolet (UV) and [OII]{\lambda}3727 luminosities for dust extinction and
dust-corrected estimates of SFR. In the selection procedure we fully exploit
the available spectroscopic information. On the basis of three continuum
indices, we are able to identify and exclude from the sample galaxies in which
old stellar populations might bring a non-negligible contribution to IR
luminosity (LIR) and continuum reddening. Using Spitzer-MIPS and Herschel-PACS
data we derive LIR for two-thirds of our sample. The LIR/LUV ratio is used as a
probe of effective attenuation (AIRX) to search for correlations with continuum
and spectroscopic features. The relation between AIRX and UV continuum slope
({\beta}) was tested for our sample and found to be broadly consistent with the
literature results at the same redshift, though with a larger dispersion with
respect to UV-selected samples. We find a correlation between the rest-frame
equivalent width (EW) of the [OII]{\lambda}3727 line and {\beta}, which is the
main result of this work. We therefore propose the [OII]{\lambda}3727 line EW
as a dust attenuation probe and calibrate it through AIRX, though the
assumption of a reddening curve is still needed to derive the actual
attenuation towards the [OII]{\lambda}3727 line. We tested the issue of
differential attenuation towards stellar continuum and nebular emission: our
results are in line with the traditional prescription of extra attenuation
towards nebular lines. A set of relations is provided that allows the recovery
of the total unattenuated SFR from UV and [OII]{\lambda}3727 luminosities.
(Abridged)Comment: Accepted for publication in A&A; 20 pages, 19 figures, 5 table
Integration as Service: Implications of Faith-Praxis Integration for Training
Faith-praxis integration should be given further attention as the integration of applied psychology and Christian theology proceeds. The authors outline a rationale for faith-praxis integration based upon patterns of mental health needs and resources in the U.S. and for a Kingdom mandate. Implications of a faith-praxis perspective for trainers of Christian psychologists are suggested in relation to a programâs missions statement, faculty, course work, practical training, research, and relationship to the community. Selected activities of existing Christian psychology training programs are included to illustrate these implications. Ongoing discussion is invited concerning this emerging area of integration
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