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The discovery of the cyanobiphenyl and related compounds in 1973 not only played a significant role in important innovations in displays and related technologies but also opened opportunities for testing of novel insights in understanding phase transitions and critical phenomena. In the study of these phenomena, high-resolution calorimetry made substantial contributions. In this paper, we present an overview of the high-resolution calorimetry results obtained during the past 50 years on the phase transitions that occur in the cyanobiphenyl compounds. For the isotropic–nematic and isotropic–smectic A transitions, their (weakly) first-order nature is well established and the temperature dependence of the pretransitional-specific heat capacity strongly points in the direction of a nearby tricritical point. For the nematic-smectic A transition, precise latent heat values of several binary liquid crystal (mainly of cyanobiphenyl type) mixtures give significant evidence on the Halperin, Lubensky and Ma prediction of the always weakly first-order nature of this transition. The dependence of the specific heat capacity critical exponent α on the width of the nematic range, resulting from coupling between the nematic and the smectic order parameters as pointed out by de Gennes, is well confirmed. [ABSTRACT FROM AUTHOR]

Verification is done on the feasibility of a neural network radiometric photothermal depth profiling method by using well-defined artificial samples with varying optical properties across the layers. Accurate reconstructions are obtained for heat source and optical-absorption coefficient profiles from simulated and experimental radiometric signals.

In high-resolution adiabatic scanning calorimetry (ASC) experiments, data for the temperature dependence of the specific enthalpy, h(T), and of the specific heat capacity, cp(T), are simultaneously obtained, from which the order of the phase transition and critical behaviour can be evaluated. ASC was applied to study the nematic to ferroelectric nematic phase transition (N–NF) in the liquid crystal molecule 4-[(4-nitrophenoxy)carbonyl]phenyl 2,4-dimethoxybenzoate (RM734). The N–NF was found to be very weakly first order with a latent heat Δh = 0.115 ± 0.005 J/g. The pretransitional specific heat capacity behaviour is substantially larger in the high-temperature N phase than in the low-temperature NF phase. In both phases the power-law analysis of cp(T) resulted in a critical exponent α = 0.50 ± 0.05 and amplitude ratio ANF/AN = 0.42 ± 0.03. The very small latent heat and the value of α indicate that the N–NF transition is close to a tricritical point. This is confirmed by a value of the order parameter exponent β ≈ 0.25, recently obtained from electric polarisation measurements. Invoking two-scale-factor universality, it follows from the low value of ANF/AN ratio that the size of the critical fluctuations is much larger in the NF phase than in the N phase. [ABSTRACT FROM AUTHOR]

Ultrasonic imaging is the noninvasive clinical imaging modality of choice for diagnosing heart disease. At present, two-dimensional ultrasonic grayscale images provide a relatively cheap, fast, bedside method to study the morphology of the heart. Several methods have been proposed to assess myocardial function. These have been based on either grayscale or motion (velocity) information measured in real-time. However, the quantitative assessment of regional myocardial function remains an important goal in clinical cardiology. To do this, ultrasonic strain and strain-rate imaging have been introduced. In the clinical setting, these techniques currently only allow one component of the true three-dimensional deformation to be measured. Clinical, multidimensional strain (rate) information can currently thus only be obtained by combining data acquired using different transducer positions. Nevertheless, given the appropriate postprocessing, the clinical value of these techniques has already been shown. Moreover, multidimensional strain and strain-rate estimation of the heart in vivo by means of a single ultrasound acquisition has been shown to be feasible. In this paper, the new techniques of ultrasonic strain rate and strain imaging of the heart are reviewed in terms of definitions, data acquisition, strain-rate estimation, postprocessing, and parameter extraction. Their clinical validation and relevance will be discussed using clinical examples on relevant cardiac pathology. Based on these examples, suggestions are made for future developments of these techniques. Index Terms--Cardiac function, echocardiography, myocardial deformation, strain, strain rate.

Phase-mask technology is used to laser-excite acoustic waves in a fluid-loaded film. Sensitive optical detection of film displacements and the monochromatic character of the optical grating excited leaky Lamb waves, allowing an examination of their existence and characteristics.

The feasibility of two-dimensional motion- and strain-rate estimation of the human heart in vivo is investigated.

The Rayleigh wave spectroscopy for reconstruction of elasticity of multilayers is examined.

The electrocaloric heat production in BaTiO 3 -based multilayer ceramic capacitors with Y5V specification was measured in a direct way by means of an adiabatic calorimeter setup. Applying an electric field of 30 MV m - 1 is found to result in a heat release of 0.94 J g - 1 and an electrocaloric temperature change of 0.46 K, in good agreement with direct results in previous studies. [ABSTRACT FROM AUTHOR]

An investigation was conducted to determine the effectiveness of a method which can be used to derive the evolution equation for the nonlinear Scholte wave. The evolution equations for nonlinear Scholte waves, which include finite amplitude elastic waves propagating along liquid/solid interface, were analyzed through mathematical simplicity and nonlinearity of solid. Results showed that the influence of nonlinearity of a solid on the considered processes is expected to be weak in the case of weak localization.

Bessel functions enable the resolution of the problem of plane thermal waves in media having linearly-changing thermal conductivity, when the internal heat sources are not functioning. The solution obtained is accurate, since internal heat source is produced by optical absorption. The linear thermal conductivity is determined by the inverse calculation method.

The nature of the critical behavior in the refractive index n is revisited in the framework of the complete scaling formulation. A comparison is made with the critical behavior of n as derived from the Lorentz-Lorenz equation. Analogue anomalies to those predicted for the dielectric constant &eh;, namely, a leading |t|2β singularity in the coexistence-curve diameter in the two-phase region and a |t|1-α along the critical isopleth in the one phase region, are expected in both cases. However, significant differences as regards the amplitudes of both singularities are obtained from the two approaches. Analysis of some literature data along coexistence in the two-phase region and along the critical isopleth in the one-phase region provide evidence of an intrinsic effect, independent of the density, in the critical anomalies of n. This effect is governed by the shift of the critical temperature with an electric field, which is supposed to take smaller values at optical frequencies than at low frequencies in the Hz to MHz range. [ABSTRACT FROM AUTHOR]

Dielectric constant measurements have been carried out in the one- and two-phase regions near the critical point of the polar + polar binary liquid mixture nitromethane + 3-pentanol. In the two-phase region, evidence for the |t|2β singularity in the coexistence-curve diameter has been detected, thus confirming the novel predictions of complete scaling theory for liquid-liquid criticality. In the one-phase region, an 'unusual' negative sign for the amplitude of the |t|1 - α singularity has been encountered for the first time in an upper critical solution temperature type of binary liquid mixture at atmospheric pressure. Mass density measurements have also been carried out to provide additional information related to such experimental finding, which entails an increase of the critical temperature Tc under an electric field. [ABSTRACT FROM AUTHOR]