Search results for "AMPER"
showing 10 items of 193 documents
Spatially limited diffusion coupled with ohmic potential drop and/or slow interfacial exchange: a new method to determine the diffusion time constant…
2004
Abstract We have analyzed chronoamperometric curves, I ( t ), after small-amplitude potential steps Δ E (PITT technique) for the model of linear diffusion of a species inside an electroactive film, taking into account ohmic effects in the external media (solution and electrode) as well as a finite rate of the interfacial exchange. For its short-time interval, t ≪ τ d ( τ d is the diffusion time constant, corresponding to unlimited diffusion from the interface), three approximate analytical expressions have been proposed. One of these represents an interpolation formula between the value of the current at the start of the diffusion process, I (0)=Δ E / R ext (after the end of the EDL chargin…
Gaseous sensors based on solid proton conductors
1992
Abstract he chemical sensors for different gaseous (alcohol, acetone, ammonia, water vapour) detection at room temperature are developed by using polycrystalline β-alumina and xerogel of antimonic acid hydrate (AAH). The sensitivity and selectivity of sensors depend on the ion-exchange and preparative methods. The possibility of producing different types of potentiometric, amperometric, voltammetric and resistance sensors on the basis of these ion-conducting materials is shown. More success is achieved by producing ammonia-sensitive devices on β-alumina as well as on AAH xerogel.
Determination of hydroquinone and metal in photographic developer by reversed-phase ion-pair chromatography with amperometric detection
1988
Abstract Sodium 1-heptanesulphonate is used as an ion-pair reagent for the chromatographic separation of the two developing agents on a phenylsilica micro-column, with amperometric detection at an applied potential of + 0.75 V (vs. Ag/AgCl). No pretreatment of the developer is necessary. Linear calibration graphs were obtained in the range 10 −5 -1.5 × 10 −4 M.
A Novel Solution to Find the Dynamic Response of an Euler–Bernoulli Beam Fitted with Intraspan TMDs under Poisson Type Loading
2020
This contribution considers a virtual experiment on the vibrational response of rail and road bridges equipped with smart devices in the form of damping elements to mitigate vibrations. The internal damping of the bridge is considered a discontinuity that contain a dashpot. Exact complex eigenvalues and eigenfunctions are derived from a characteristic equation built as the determinant of a 4 x 4 matrix
Analysis of block random rocking on nonlinear flexible foundation
2020
Abstract In this paper the rocking response of a rigid block randomly excited at its foundation is examined. A nonlinear flexible foundation model is considered accounting for the possibility of uplifting in the case of strong excitation. Specifically, based on an appropriate nonlinear impact force model, the foundation is treated as a bed of continuously distributed springs in parallel with nonlinear dampers. The statistics of the rocking response is examined by an analytical procedure which involves a combination of static condensation and stochastic linearization methods. In this manner, repeated numerical integration of the highly nonlinear differential equations of motion is circumvent…
Innovations and ecosystems : a characterization of Smart Tampere innovation ecosystem
2019
Master's thesis Innovative governance and public management ME523 - University of Agder 2019 The following thesis focuses on innovation ecosystem. As described in thefirst section, innovations are of great importance for tackling global challenges such as climate change andthus,of relevancy for the regional economic development. The growing importance of innovationshas motivated numerous new approaches to innovation management, especiallyin the last years the approach ofinnovation ecosystem.In the secondsection, the concept of innovation ecosystem is introduced and the most relevantconcepts from the literature are discussed. It thereby compares innovation ecosystem to other concepts such as…
Seismic Performance of Earthquake-Resilient RC Frames Made with HSTC Beams and Friction Damper Devices
2021
Seismic behavior of RC frames with hybrid steel-trussed concrete beams is affected by panel zone damage due to a large amount of longitudinal reinforcement. Here the seismic efficiency of innovative frames characterized by friction damper devices (FDDs) at beam-to-column connections is compared against traditional frame. Three configurations are investigated: FDDs alone; FDDs with column-to-foundation connections having preloaded threaded bars and disk springs; FDDs with self-centering friction devices. Non-linear analyses show that FDDs alone prevent plastic hinge formation at beam ends and beam–column joint damage. FDDs with self-centering friction devices effectively limit both peak and …
La enseñanza basada en preguntas : La ley de Ampère y el término de Maxwell
2020
Frecuentemente a los maestros de Física y de Matemáticas se les recomienda una enseñanza activa de estas áreas del conocimiento, que consiste en una interacción continua entre el maestro y el estudiante. Con una metáfora de un interrogatorio adecuado, se pretende mostrar al docente una manera de orientar al estudiante en su aprendizaje, motivándolo a recuperar conocimientos previos o causándole un conflicto cognitivo que lo lleve a reformular su aprendizaje. Esta manera de proceder didácticamente se ha llamado enseñanza basada en preguntas, cuya primera referencia histórica nos remite a la Grecia antigua. En este trabajo se presenta la enseñanza de la ley de Ampère con la generalización de …
Optimal damping coefficient for a class of continuous contact models
2020
AbstractIn this study, we develop an analytical formula to approximate the damping coefficient as a function of the coefficient of restitution for a class of continuous contact models. The contact force is generated by a logical point-to-point force element consisting of a linear damper connected in parallel to a spring with Hertz force–penetration characteristic, while the exponent of deformation of the Hertz spring can vary between one and two. In this nonlinear model, it is assumed that the bodies start to separate when the contact force becomes zero. After separation, either the restitution continues or a permanent penetration is achieved. Therefore, this model is capable of addressing …
Solutions for the Design and Increasing of Efficiency of Viscous Dampers
2016
In last decades many strategies for seismic vulnerability mitigation of structures have been studied and experimented; in particular energy dissipation by external devices assumes a great importance for the relative simplicity and efficacy. Among all possible approaches the use of fluid viscous dampers are very interesting, because of their velocity-dependent behaviour and relatively low costs. Application on buildings requires a specific study under seismic excitation and a particular attention on structural details. Nevertheless seismic codes give only general information and in most case the design of a such protection systems results difficult; this problem is relevant also in Italy whe…