Authors:C. Auguet, A. Isalgué, F. Lovey, F. Martorell, and V. Torra
The behavior of shape memory alloys (SMA) allows their use as a passive
smart material. In particular, the existence of a hysteretic cycle in the
domain of the elementary coordinates strain-stress-temperature (σ, ε, T) suggests its application for damping
in mechanical and/or in civil engineering. We are working in the application
of SMA as dampers for earthquakes in small houses as family homes. For dampers
installed in the inner porticos of the house, the suggested SMA is the CuAlBe
and, eventually, the NiTi. At room temperature the used SMA wires induces
forces situated between 2–3kN/wire. The properties related with the
damping applications for CuAlBe and NiTi, i.e., the SMA creep and the self-heating
will be presented, together with some other minor stress and temperature effects
on NiTi modifying the hysteretic behavior.
Authors:C. Auguet, F. Martorell, F. Moll, and V: Torra
The miniaturized calorimetric devices furnish a reduced working flat surface and permits measurements with extremely low-mass
quantities. The experimental sensitivity shows relevant position dependence with x-y surface coordinates and with z-distance. The device identification is realized via a 2-D model based in Fourier general equation.
Using the Marquardt method the experimental flat surface device can be identified and the fitted parameters used to simulate
the behavior of the experimental system. From the model, the effects of several dissipation configurations can be evaluated.
Also, via the RC-analogy, a way to 3-D experimental devices is roughly described.
Authors:C. Auguet, J. Seguin, F. Martorell, F. Moll, V. Torra, and J. Lerchner
devices using Si-based sensors are very useful for the study of gas–solid
reactions, in which very low mass of reactants are necessary. But in fact
the consequence of using flat detectors is an increase of the uncertainty
in the measured energy. In this work a calorimetric gas sensor based on Xensor
chip is analysed studying the local x–y
contributions of dissipation to the sensitivity related to the value in the
centre. We study also the effects of the gas-flow on the sensitivity, comparing
the results obtained with two Xensor type chips. Finally we carry out a deeper
analysis of the x–y effects on the
calorimetric detector for dissipations in the reactant shell extremely close
to the detector surface to visualize the link between the power density distribution
and the output signal.
Authors:C. Auguet, J. Lerchner, P. Marinelli, F. Martorell, M. Rodriguez de Rivera, V. Torra, and G. Wolf
The experimental analysis of conventional conduction calorimeters shows excellent reproducibility and relevant systematic
errors in comparison with thermodynamic values established via adiabatic calorimeters. Two examples: a DSC and a liquid flow
device are schematically analyzed. When an increased accuracy will be obtained the positional effects on the experimental
set-up and on the measurement process need to be modelled. From experimental measurements realized on the Xensor liquid nano-calorimeter
representative models can be built. To evaluate the reliability of measurement routines, established from experimental basis,
several different dissipation structures inside the working space can be simulated. Two experimental configurations related
to drop to drop reaction and to continuous mixing are modelled via RC approach. The RC formalism is extended to evaluate the
carried energy effect produced by the continuous inflow/outflow of reactants in the mixing enthalpy chamber.