Search results for "control systems"
showing 10 items of 590 documents
Elastic-Viscoplastic Solids Subjected to Thermal and Loading Cycles
1995
— A class of elastic-viscoplastic materials with dual internal variables, thermodynamic potential and temperature-dependent plastic and creep data is considered. For solids (or structures) of such materials, subjected to cyclic loads and temperature variations, the existence of a steady-state response is ascertained and its periodicity characteristics established. Particular steady-state responses, like, elastic and inelastic shakedown, are addressed. By means of a sensitivity analysis of the steady cycle with respect to the load parameter changes, a number of basic features of inelastic shakedown (the viscoplastic counterpart of plastic shakedown) are also addressed.
Polarimetric Plasmonic Sensing with Bowtie Nanoantenna Arrays
2015
We propose a polarimetric plasmonic biosensor based on bowtie nanoantenna array transducers. Through numerical simulations, based on the finite element method (FEM), we study the phase retardation between the components of light polarized parallel and perpendicular to the major axis of the bowties within the arrays. From a design for high volumetric sensitivity at a wavelength of 780 nm, sensitivities ∼5 rad/RIU is obtained, corresponding to a detection limit of ∼10−7 when using a polarimetric readout platform. Similarly, surface sensitivity of the same array is evaluated by simulating the phase retardation changes induced by the coverage of bioreceptors and analytes of the metallic nanostr…
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…
Scaling the Sensitivity of Integrated Plasmo-Photonic Interferometric Sensors
2019
We present a new optical biosensing integration approach with multifunctional capabilities using plasmonic and photonic components on the same chip and a new methodology to design interferometric b...
Cylindrical Cell-Based Refractometers to Analyse Biomedical Liquids
2015
Compact device of high sensitivity for measurement of the refractive indices of both stationary and flowing liquids has been developed. This device can be used to analyse a variety of biomedical liquids: urine, serum protein. The refractive index (RI) is determined by measuring the deviation of a laser beam passing through a cylindrical cell containing the test liquid. In order to significantly improve the resolution and stability of RI measurements, the repeated reflections and refractions of the light beam travelling through the cylindrical cell are employed.
Narrowing the Plasmonic Sensitivity Distribution by Considering the Individual Size of Gold Nanorods
2018
The plasmonic nanoparticle sensitivity, sensing volume, and the signal-to-noise ratio are strongly dependent on the nanoparticle dimensions. It is difficult to chemically produce or purify nanoparticles with a size variation of less than 10%. This size variation induces a systematic error in sensing experiments that can be reduced when the exact size of each individual nanoparticle is known. In this work, we show how the size of gold nanorods can be estimated directly from the optical spectra of single nanoparticles by using the increase of radiation damping with the nanoparticle size. We verify our approach by comparing these spectrally estimated sizes with the precise sizes of exactly the…
CNT-based RFID passive gas sensor
2011
Summary form only given, as follows. Single-wall carbon nanotube (CNT) is examined for the design of a passive and maintenance-free wireless RFID sensor. CNT buckypaper is characterized from a dielectric and a sensitivity point of view, using an indirect way, by using antenna measurement and simulations in a controlled medium. A CNT-based prototype RFID tag is then described as the featured maintenance free sensor and experimentally verified for its applicability and sensitivity towards NH3.
Theoretical and Empirical Underpinnings of Maternal Sensitivity: Considerations of Sensitivity Across Cultures and Socioeconomic Status
2021
This chapter presents a comprehensive overview of maternal sensitivity and its predictors, along with the assumptions that explain its repercussions on child development and evidence of these relations. We first present the conceptual and operational definitions of maternal sensitivity espoused by Attachment Theory. Next, we summarize predictors of maternal sensitivity, emphasizing how maternal mental health issues and economic vulnerability can hinder mothers’ ability to sensitively respond to their infants. Finally, we discuss longitudinal studies and meta-analyses which show how maternal sensitivity predicts numerous domains of child development.
Sensitivity Maps of the Hilbert-Schmidt Independence Criterion
2018
Abstract Kernel dependence measures yield accurate estimates of nonlinear relations between random variables, and they are also endorsed with solid theoretical properties and convergence rates. Besides, the empirical estimates are easy to compute in closed form just involving linear algebra operations. However, they are hampered by two important problems: the high computational cost involved, as two kernel matrices of the sample size have to be computed and stored, and the interpretability of the measure, which remains hidden behind the implicit feature map. We here address these two issues. We introduce the sensitivity maps (SMs) for the Hilbert–Schmidt independence criterion (HSIC). Sensi…
On the Computation of the Efficient Frontier of the Portfolio Selection Problem
2012
An easy-to-use procedure is presented for improving theε-constraint method for computing the efficient frontier of the portfolio selection problem endowed with additional cardinality and semicontinuous variable constraints. The proposed method provides not only a numerical plotting of the frontier but also an analytical description of it, including the explicit equations of the arcs of parabola it comprises and the change points between them. This information is useful for performing a sensitivity analysis as well as for providing additional criteria to the investor in order to select an efficient portfolio. Computational results are provided to test the efficiency of the algorithm and to i…