Search results for "Experimental validation"
showing 10 items of 37 documents
Experimental validation of a fractional model for creep/recovery testing of asphalt mixtures
2012
Abstract Prediction of asphalt mixtures’ behavior during their service life is a challenge due to its complexity and sensitivity to environmental and loading conditions. It has been proved that, when subjected to loading conditions comparable with most pavement operating conditions, asphalt mixtures behave as linear visco-elastic (LVE) materials. Traditionally the LVE behavior of bituminous material is modeled via creep/recovery functions. In the past, several rheological models constituted by elastic and viscous elements arranged in series or in parallel (analogical models) have been proposed and specified for both bitumen and asphalt mixtures. The corresponding constitutive laws always in…
Generalized Multitarget Linear Regression with Output Dependence Estimation
2019
Multitarget regression has recently received attention in the context of modern, large-scale problems in which finding good enough solutions in a timely manner is crucial. Different proposed alternatives use a combination of regularizers that lead to different ways of solving the problem. In this work, we introduce a general formulation with several regularizers. This leads to a biconvex minimization problem and we use an alternating procedure with accelerated proximal gradient steps to solve it. We show that our formulation is equivalent but more efficient than some previously proposed approaches. Moreover, we introduce two new variants. The experimental validation carried out, suggests th…
Adaptation of the Human Gut Microbiota Metabolic Network During the First Year After Birth
2019
Predicting the metabolic behavior of the human gut microbiota in different contexts is one of the most promising areas of constraint-based modeling. Recently, we presented a supra-organismal approach to build context-specific metabolic networks of bacterial communities using functional and taxonomic assignments of meta-omics data. In this work, this algorithm is applied to elucidate the metabolic changes induced over the first year after birth in the gut microbiota of a cohort of Spanish infants. We used metagenomics data of fecal samples and nutritional data of 13 infants at five time points. The resulting networks for each time point were analyzed, finding significant alterations once sol…
Experimental validation of a novel compact focusing scheme for future energy-frontier linear lepton colliders.
2014
A novel scheme for the focusing of high-energy leptons in future linear colliders was proposed in 2001 [ P. Raimondi and A. Seryi , Phys. Rev. Lett. 86 , 3779 ( 2001 ) ]. This scheme has many advantageous properties over previously studied focusing schemes, including being significantly shorter for a given energy and having a significantly better energy bandwidth. Experimental results from the ATF2 accelerator at KEK are presented that validate the operating principle of such a scheme by demonstrating the demagnification of a 1.3 GeV electron beam down to below 65 nm in height using an energy-scaled version of the compact focusing optics designed for the ILC collider.
Liquid-liquid phase coexistence in gold clusters. 2D or not 2D?
2006
The thermodynamics of gold cluster anions (${\mathrm{Au}}_{N}^{\ensuremath{-}}$, $N=11,\dots{},14$) is investigated using quantum molecular dynamics. Our simulations suggest that ${\mathrm{Au}}_{N}^{\ensuremath{-}}$ may exhibit a novel, freestanding planar liquid phase which dynamically coexists with a normal three-dimensional liquid. Upon cooling with experimentally realizable cooling rates, the entropy-favored three-dimensional liquid clusters often supercool and solidify into the ``wrong'' dimensionality. This indicates that experimental validation of theoretically predicted ${\mathrm{Au}}_{N}^{\ensuremath{-}}$ ground states might be more complicated than hitherto expected.
Colloquium: Laboratory experiments on hydromagnetic dynamos
2002
Cosmic magnetic fields, including the fields of planets, stars, and galaxies, are believed to be caused by dynamo action in moving electrically conducting fluids. While the theory and numerics of hydromagnetic dynamos have flourished during recent decades, an experimental validation of the effect was missing until recently. We sketch the long history towards a working laboratory dynamo. We report on the first successful experiments at the sodium facilities in Riga and Karlsruhe, and on other experiments which are carried out or planned at various places in the world.
Pressure drop at low reynolds numbers in woven-spacer-filled channels for membrane processes: CFD prediction and experimental validation
2017
The energy consumption due to pumping power is a crucial issue in membrane processes. Spacers provide mechanical stability and promote mixing, yet increasing pressure drop. Woven spacers and their behaviour at low Reynolds numbers are less studied in the literature. Nevertheless, they are typical of some membrane technologies, as reverse electrodialysis (RED). RED is a promising technology for electric power generation by the chemical potential difference of two salt solutions within a stack equipped by selective ion-exchange membranes. The mechanical energy required for pumping the feed solutions, can dramatically reduce the net power output. In this work computational fluid dynamics (CFD)…
On the experimental validation of an improved five-parameter model for silicon photovoltaic modules
2012
Abstract This paper presents the experimental validation of a new five-parameter model capable of analytically describing the I–V characteristic of a silicon photovoltaic module for each generic condition of operative temperature and solar irradiance. The operating current calculated with the model was validated on the basis of a series of experimental measurements performed in the field on two commercial silicon photovoltaic panels connected to a set of nine constant values of the electrical load. In order to examine the panels working in almost steady-state conditions only the data-sets of the sunniest days from sunrise to sunset were used. Unfortunately the production spread of photovolt…
Design Procedures for Soil-Lime Stabilization for Road and Railway Embankments. Part 2-Experimental Validation
2012
AbstractAs detailed in Part 1, the most common Italian Technical Specifications refer to different design methodologies for design of lime-soil mixtures, some being quite different from those internationally adopted. Therefore, it seemed appropriate to the Authors to compare these methodologies, via a wide experimental program.It is shown that the Italian methodology of the National Road Agency is different not only from those used in Italy, but also from the main international standards. The experimental results highlight that a revision of that methodology is needed in order to bring it into line with what is prescribed by the European standard.
Extended Kalman Filter for sensorless control of induction motors
2010
This paper deals with speed and rotor flux estimation of induction motors via Extended Kalman Filter (EKF). The filter is designed starting from a discrete time model obtained by means of a first order discretization of the original nonlinear model of the induction motor (IM). In order to obtain accurate estimation of the above mentioned variables, the load torque is included into the state variables and then estimated, thus constructing a sixth order EKF. Experimental results are shown with reference to a closed loop sensorless control system, consisting of a 750 W induction motor supplied by a voltage source inverter, a cascade controller consisting of four PI control loops and the design…