Search results for "equivalent"

A PV plant simulator for testing MPPT techniques

2013

This paper introduces a versatile and reliable photovoltaic systems simulator. It includes the main components of a photovoltaic plant: a PV string and a PWM controlled boost chooper. The key feature of this simulator is the ability to consider different and non-uniform irradiation and temperature conditions (partial shading and partial heating of the strings). All the different I-V and P-V or P-I characteristics can then be determined in such non-uniform irradiation and temperature conditions, with the aim to try different MPPT algorithms. The simulator also allows to verify an enhanced version of the Incremental Conductance algorithm (IncCond) where, in order to reach the real absolute ma…

Caratterizzazione meccanica di pannelli di tamponamento per la identificazione di puntoni equivalenti nell’analisi di strutture intelaiate

2008

Assessment of image quality of intracoronary ultrasound systems with tissue-equivalent vessel phantoms

2002

Imaging of vascular structures by intracoronary ultrasound (ICUS) is finding more and more applications in coronary diagnosis and in the assessment of interventional access. The authors describe a method for easy and quick production of tissue-equivalent vessel phantoms from a special hydrocolloid. The mechanical tolerance is less than 3/100 mm. With these phantoms the authors tested the calibration and measured the resolution properties of the SONOS intravascular ultrasonic system (Hewlett Packard). The measurements revealed a slight space related underestimation of diameters up to 280 /spl mu/m. Using cross correlation and auto correlation functions the authors analyzed digitized ultrason…

Analysis of Transition Metal Oxides based Heterojunction Solar Cells with S-shaped J-V curves

2020

The use of transition metal oxides for the selective carrier contact in the crystalline silicon solar cells technology is rising to interest for the excellent optoelectrical properties of these materials whose implementation, however, can result in lousy performing cells due to an S-shaped electrical characteristic. In this paper, we fabricated solar cells showing S-shaped J-V curve and carried out an analysis of the reasons of such behavior using a model involving the series of a standard cell equivalent circuit with a Schottky junction in order to explain these atypical performances. A good matching between the experimental measurements and the adopted theoretical model was obtained. The …

Mediterranean Diet and Physical Activity Decrease the Initiation of Cardiovascular Drug Use in High Cardiovascular Risk Individuals: A Cohort Study

2021

Our aim was to assess whether long-term adherence to a Mediterranean diet (MedDiet) and leisure-time physical activity (LTPA) were associated with a lower initiation of cardiovascular drug use. We studied the association between cumulative average of MedDiet adherence and LTPA and the risk of cardiovascular drug initiation in older adults at high cardiovascular risk (PREvención con DIeta MEDiterránea trial participants) non-medicated at baseline: glucose-lowering drugs (n = 4437), antihypertensives (n = 2145), statins (n = 3977), fibrates (n = 6391), antiplatelets (n = 5760), vitamin K antagonists (n = 6877), antianginal drugs (n = 6837), and cardiac glycosides (n = 6954). One-point increas…

Calibrating a microscopic traffic simulation model for roundabouts using genetic algorithms

2018

The paper introduces a methodological approach based on genetic algorithms to calibrate microscopic traffic simulation models. The specific objective is to test an automated procedure utilizing genetic algorithms for assigning the most appropriate values to driver and vehicle parameters in AIMSUN. The genetic algorithm tool in MATLAB® and AIMSUN micro-simulation software were used. A subroutine in Python implemented the automatic interaction of AIMSUN with MATLAB®. Focus was made on two roundabouts selected as case studies. Empirical capacity functions based on summary random-effects estimates of critical headway and follow up headway derived from meta-analysis were used as reference for ca…

Steady-state dynamic response of various hysteretic systems endowed with fractional derivative elements

2019

In this paper, the steady-state dynamic response of hysteretic oscillators comprising fractional derivative elements and subjected to harmonic excitation is examined. Notably, this problem may arise in several circumstances, as for instance, when structures which inherently exhibit hysteretic behavior are supplemented with dampers or isolators often modeled by employing fractional terms. The amplitude of the steady-state response is determined analytically by using an equivalent linearization approach. The procedure yields an equivalent linear system with stiffness and damping coefficients which are related to the amplitude of the response, but also, to the order of the fractional derivativ…

Defined-size DNA triple crossover construct for molecular electronics: modification, positioning and conductance properties.

2011

We present a novel, defined-size, small and rigid DNA template, a so-called B-A-B complex, based on DNA triple crossover motifs (TX tiles), which can be utilized in molecular scale patterning for nanoelectronics, plasmonics and sensing applications. The feasibility of the designed construct is demonstrated by functionalizing the TX tiles with one biotin-triethylene glycol (TEG) and efficiently decorating them with streptavidin, and furthermore by positioning and anchoring single thiol-modified B-A-B complexes to certain locations on a chip via dielectrophoretic trapping. Finally, we characterize the conductance properties of the non-functionalized construct, first by measuring DC conductivi…

Comparison of Variance and Damage Indicator Methods for Prediction of the Fracture Plane Orientation in Multiaxial Fatigue

1999

ABSTRACT Two methods that enable prediction of the fracture plane orientation are presented and compared in this paper. The first one is a statistical approach, which is based on the variance of an equivalent stress. It is assumed that the fracture plane is the one where the variance of a linear combination of the shear and normal stresses acting on this plane is maximum. The second one uses the so-called damage indicator of a multiaxial fatigue criterion, which is based on the research of the critical plane. The formulation of the criterion involves shear and normal stress amplitudes and mean normal stress. The fracture plane is the critical plane; That is to say the one where the damage i…

Thermoelastic Stress Analysis by Means of a Standard Thermocamera and a 2D-Fft Based Lock-In Technique

2007

The thermoelastic effect in a generic orthotropic body under adiabatic and linear elastic stress conditions induces small and reversible temperature changes that can be correlated with the stress field by means of linear relationships. Infrared techniques are mainly used to measure temperature changes on the component surface [1], while adiabatic conditions are generally achieved by applying cyclic loads above a threshold frequency. The resolution resulting from implementing a Thermoelastic Stress Analysis (TSA) technique is a combination of the infrared acquiring system resolution and of the signal post-processing procedure. State of the art infrared detectors have NETD (Noise Equivalent T…