Numerical simulation of the oscillating ferromagnetic yoke in the magnetic field of a cylindrical permanent magnet without and with a short-circuited multi-turn coil was performed. Finite-element ...method (FEM) analysis based on the fundamental Maxwell equations and the Maxwell stress tensor approach was used. Due to induction of eddy currents in the volume of the conducting yoke, as well as in the other parts of the magnetic circuit, eddy current damping (ECD) occurs. There is some influence of the current circulating in the short-circuited coil. The shift of resonance frequency of studied systems to the lower values in comparison to the solely mechanical system was more significant for mechano-electromagnetic systems without the short-circuited coil than for the same system with the short-circuited coil. Also, the damping was higher without the short-circuited coil than with the coil. Good agreement with results obtained from experiments, as well as from the simplified analytic model, was observed. It follows that the addition of short-circuited coil deteriorates the vibration control properties of the system based solely on the ECD.
Estimating rates of COVID-19 infection and associated mortality is challenging due to uncertainties in case ascertainment. We perform a counterfactual time series analysis on overall mortality data ...from towns in Italy, comparing the population mortality in 2020 with previous years, to estimate mortality from COVID-19. We find that the number of COVID-19 deaths in Italy in 2020 until September 9 was 59,000-62,000, compared to the official number of 36,000. The proportion of the population that died was 0.29% in the most affected region, Lombardia, and 0.57% in the most affected province, Bergamo. Combining reported test positive rates from Italy with estimates of infection fatality rates from the Diamond Princess cruise ship, we estimate the infection rate as 29% (95% confidence interval 15-52%) in Lombardy, and 72% (95% confidence interval 36-100%) in Bergamo.
To compare the long-term outcome of patients with previously untreated follicular lymphoma (FL) needing therapy, after treatment with cyclophosphamide, vincristine and prednisone (CVP) versus CVP ...plus rituximab (R-CVP) and to evaluate the predictive value of known prognostic factors after treatment with R-CVP.
Patients with previously untreated CD20-positive stage III/IV FL were randomly assigned to eight cycles of R-CVP (n = 159) or CVP alone (n = 162). The median follow-up period was 53 months.
The primary end point-time to treatment failure (TTF), which included patients without a response after four cycles as an event-was significantly prolonged in patients receiving R-CVP versus CVP (P < .0001). Improvements in all other end points, including overall and complete response rates (P < .0001), time to progression (TTP; P < .0001), response duration (P < .0001), time to next antilymphoma treatment (P < .0001), and overall survival (OS; P = .029; 4-year OS: 83% v 77%;) were achieved with R-CVP versus CVP alone. Univariate analyses demonstrated an improvement in TTP with R-CVP versus CVP irrespective of the Follicular Lymphoma International Prognostic Index (FLIPI) subgroup, the International Prognostic Index (IPI) subgroup, baseline histology, and the presence or absence of B symptoms or bulky disease. By multivariate analysis, FLIPI retains a strong predictive power for TTP in the presence of the trial treatment effect.
Analysis of all outcome measures, including OS, confirm the benefit of adding R to CVP in the front-line treatment of FL.
Line-intensity mapping is an emerging field of observational work, with strong potential to fit into a larger effort to probe large-scale structure and small-scale astrophysical phenomena using ...multiple complementary tracers. Taking full advantage of such complementarity means, in part, undertaking line-intensity surveys with galaxy surveys in mind. We consider the potential for detection of a cross-correlation signal between COMAP and blind surveys based on photometric redshifts (as in COSMOS) or based on spectroscopic data (as with the HETDEX survey of Ly emitters). We find that obtaining accuracy in redshifts and 10−4 sources per Mpc3 with spectroscopic redshift determination should enable a CO-galaxy cross spectrum detection significance at least twice that of the CO auto spectrum. Either a future targeted spectroscopic survey or a blind survey like HETDEX may be able to meet both of these requirements.
This study presents original new results on measured whole-body vibration (WBV) on passenger's seat surface and seat base as a function of measured road unevenness in the longitudinal direction. ...Measurements were provided on nine different cars of six categories operated on about 1860 km of road network. Root mean square (RMS) of the frequency-weighted acceleration was used to quantify the WBV. The relation between passenger's total vibration and road profile vertical displacement power spectral density (PSD) parameters (unevenness index, waviness) specified in standard ISO 8608: 2016 in a 200-m segment were estimated. Relation between ISO 2631-1 degrees of discomfort and ISO 8608 road classes was estimated. Measured acceleration at the passenger's seat surface and seat base was fitted by a four-parameter function of unevenness index, waviness and vehicle speed. Further considered factors were vehicle type, road category, acceleration measuring point and direction of acceleration response.
Abstract
We construct a physically parameterized probabilistic autoencoder (PAE) to learn the intrinsic diversity of Type Ia supernovae (SNe Ia) from a sparse set of spectral time series. The PAE is ...a two-stage generative model, composed of an autoencoder that is interpreted probabilistically after training using a normalizing flow. We demonstrate that the PAE learns a low-dimensional latent space that captures the nonlinear range of features that exists within the population and can accurately model the spectral evolution of SNe Ia across the full range of wavelength and observation times directly from the data. By introducing a correlation penalty term and multistage training setup alongside our physically parameterized network, we show that intrinsic and extrinsic modes of variability can be separated during training, removing the need for the additional models to perform magnitude standardization. We then use our PAE in a number of downstream tasks on SNe Ia for increasingly precise cosmological analyses, including the automatic detection of SN outliers, the generation of samples consistent with the data distribution, and solving the inverse problem in the presence of noisy and incomplete data to constrain cosmological distance measurements. We find that the optimal number of intrinsic model parameters appears to be three, in line with previous studies, and show that we can standardize our test sample of SNe Ia with an rms of 0.091 ± 0.010 mag, which corresponds to 0.074 ± 0.010 mag if peculiar velocity contributions are removed. Trained models and codes are released at
https://github.com/georgestein/suPAErnova.
This paper deals with axial oscillations of a ferromagnetic yoke above the center of a rotationally symmetric pot-like core, made of magnetically soft steel, with a cylindrical axially poled ...permanent magnet (PM) in the center. Due to the vibration of the yoke in the static magnetic field of the PM, eddy currents are generated in the yoke. These currents, in turn, generate a dynamic magnetic force counteracting the excitation force and so damping the vibrations. Moreover, static magnetic force is present, which on the one hand limits the oscillatory system performance and on the other changes the dynamics of the oscillations. Simulations are compared with experimental results on a test stand. Good agreement was reached, suggesting correctness of the presented approach to the description of this electromechanical phenomenon.
This paper deals with the analysis and simulation of a general single degree of freedom (sdof) oscillatory system with idealised linear viscous damper and dry friction. For dry friction modelling the ...phenomenological macro-slip approach is employed, described in mathematical form either by the signum function approach or by the physically correct stick–slip approach assuming switching phenomena on a short time scale. Both approaches are illustrated first using a steady-state harmonic acceleration excitation with constant amplitude and then a stationary random acceleration excitation, corresponding to a field-measured excitation in a vehicle. The differences in the two approaches are highlighted, indicating that the physically correct stick–slip approach describes the friction phenomenon better than the standard signum approach. The signum approach is prone to false numerical oscillations completely distorting the acceleration response signal in comparison to measured suspension system response. The acceleration transmissibility response is analysed in respect to the dry friction force magnitude, employing stationary random excitation. A sdof oscillatory system without viscous damping, subjected to both stationary random acceleration and harmonic acceleration is analysed, too. It is shown that such a system can be used without serious practical problems; however, no implications on its performance from the analysis under harmonic constant amplitude acceleration excitation can be made.
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