Search results for "linear"
showing 10 items of 7165 documents
Third-harmonic generation in optical microfibers: From silica experiments to highly nonlinear glass prospects
2012
International audience; Using optical microfibers, phase matching between different propagation modes allows for third-harmonic generation (THG). After detailing the relevant phase matching conditions and overlap integrals, we provide a comparison between THG effective efficiencies in silica and tellurite glasses. We also explain the relatively easy, wideband, conversion that we observe experimentally in silica glass microfibers, from 155 mu m to the green, by the geometry of the tapering region.
Helical Shift Mechanics of Rubber V-Belt Variators
2011
A very common configuration of V-belt variators for motorcycles considers the correction of the belt tensioning depending on the resistant torque by means of suitable helical-shaped tracks allowing the driven half-pulleys to close/open. The theoretical model for belt-pulley coupling is rather complex for this configuration, where one half-pulley may run in advance and the other one behind with respect to the belt, and requires the repeated numerical solution of a strongly nonlinear differential system by a sort of shooting technique, until all the operating conditions are fulfilled (angular contact extent, torque, and axial force). After solving the full equations, the present study develop…
Design and Modeling of an Interleaving Boost Converter with Quasi-Saturated Inductors for Electric Vehicles
2020
This paper is focused on the analysis and modeling of DC-DC boost converters in interleaving configuration exploiting inductors in the quasi-saturation region. The converter is designed to optimize the power density by minimizing the size of the inductors. A simulation study for electric vehicle applications is conducted analyzing the effects of duty cycle and temperature variation on the ripple of the input current giving, moreover, information on the performances and dynamics of the converter for further implementation and optimizations.
Economic Robustness Analysis of Adaptive Chart Schemes for Monitoring the Total Nonconformities Number in Inspection Units
2015
In recent years, a variety of enhanced schemes for the c chart have been developed aimed at the effectiveness improving of the related statistical process control (SPC) procedures. However, the performance of such chart schemes can be very sensitive to values assumed for some operating and cost parameters, in particular to the considered process shift magnitude arising from out-of-control conditions. In such a circumstance, the effectiveness of such chart schemes can be subjected to substantial reductions when they are implemented in operative contexts given that, in practice, such value is unknown and it can be very difficult to accurately estimate. For this reason, in the present paper i…
On the calculation of derived variables in the analysis of multivariate responses
1992
AbstractThe multivariate regression of a p × 1 vector Y of random variables on a q × 1 vector X of explanatory variables is considered. It is assumed that linear transformations of the components of Y can be the basis for useful interpretation whereas the components of X have strong individual identity. When p ≥ q a transformation is found to a new q × 1 vector of responses Y∗ such that in the multiple regression of, say, Y1∗ on X, only the coefficient of X1 is nonzero, i.e. such that Y1∗ is conditionally independent of X2, …, Xq, given X1. Some associated inferential procedures are sketched. An illustrative example is described in which the resulting transformation has aided interpretation.
Prevalence and factors associated with circadian blood pressure patterns in hypertensive patients.
2009
Comment in Timing of antihypertensive therapy and circadian blood pressure pattern. [Hypertension. 2009] Timing of antihypertensive therapy and circadian blood pressure pattern. Almirall J, Martínez-Ocaña JC, Comas L. Hypertension. 2009 Jun; 53(6):e41; author reply e42. Epub 2009 May 4. Dipping comes of age: the importance of nocturnal blood pressure. [Hypertension. 2009]. Dipping comes of age: the importance of nocturnal blood pressure. O'Brien E. Hypertension. 2009 Mar; 53(3):446-7. Epub 2009 Jan 26.Nondipping in patients with hypertension. [Hypertension. 2009] Ambulatory blood pressure (BP) monitoring has become useful in the diagnosis and management of hypertensive individuals. In addit…
Asymptomatic carotid lesions add to cardiovascular risk prediction.
2010
AIM To show that subclinical atherosclerosis (subclinical-ATS) of carotid arteries [intima-media thickness (IMT) or asymptomatic carotid plaque (ACP)], may provide additional information for risk stratification, in asymptomatic patients, aged greater than 45 years, with a cluster of risk factors (RFs). METHODS AND RESULTS We studied 558 asymptomatic patients (235 males). RFs for atherosclerosis were assessed and the 10-year-risk was calculated according to the Italian risk score. Doppler ultrasound of carotid arteries identified the presence of IMT greater than 0.9 mm in 183 patients and ACP in 147 patients. One hundred and fifty-three patients developed cerebrovascular or cardiovascular (C…
Empirical analysis of daily cash flow time-series and its implications for forecasting
2019
Usual assumptions on the statistical properties of daily net cash flows include normality, absence of correlation and stationarity. We provide a comprehensive study based on a real-world cash flow data set showing that: (i) the usual assumption of normality, absence of correlation and stationarity hardly appear; (ii) non-linearity is often relevant for forecasting; and (iii) typical data transformations have little impact on linearity and normality. This evidence may lead to consider a more data-driven approach such as time-series forecasting in an attempt to provide cash managers with expert systems in cash management.
Airy-function approach to binary black hole merger waveforms: The fold-caustic diffraction model
2022
From numerical simulations of the Einstein equations, and also from gravitational wave observations, the gravitational wave signal from a binary black hole merger is seen to be simple and to possess certain universal features. The simplicity is somewhat surprising given that non-linearities of general relativity are thought to play an important role at the merger. The universal features include an increasing amplitude as we approach the merger, where transition from an oscillatory to a damped regime occurs in a pattern apparently oblivious to the initial conditions. We propose an Airy-function pattern to model the binary black hole (BBH) merger waveform, focusing on accounting for its simpl…
A homemade device for linear sucrose gradients
2008
We have developed a simple and inexpensive device to obtain linear sucrose gradients with commonly used laboratory materials--a syringe, a flask, a plastic tube, and a piece of Pongo (Play-Doh). Refractive index values measured on sucrose fractions collected using our system demonstrate both the linearity and reliability of the gradients obtained.