Photopyroelectric Method Research Articles

Non-Contact and Self-Calibrated Photopyroelectric Method for Complete Thermal Characterization of Porous Materials.

A general theory of a photopyroelectric (PPE) configuration, based on an opaque sample and transparent pyroelectric sensor, backing and coupling fluids is developed. A combined back-front detection investigation, based on a frequency scan of the phase of the PPE signals, followed by a self-normalization of the phases' behavior, leads to the possibility of simultaneously measuring both thermal effusivity and diffusivity of a solid sample. A particular case of this configuration, with no coupling fluid at the sample/backing interface and air instead of coupling fluid at the sample/sensor interface (non-contact method) is suitable for simultaneous measurement ofboth thermal diffusivity and effusivity (in fact complete thermal characterization) of porous solids. Compared with the already proposed configurations for investigations of porous materials, this novel configuration makes use of a fitting procedure with only one fitting parameter, in order to guarantee the uniqueness of the solution. The porous solids belong to a class of materials which are by far not easy to be investigated using PPE. To the best of our knowledge, porous materials represent the only type of compounds, belonging to condensed matter, which were not taken into consideration (until recently) as potential samples for PPE calorimetric investigations. Consequently, the method proposed in this paper complete the area of applications of the PPE method. Applications on some porous building materials and cellulose-based samples validate the theory.

Toolbox for modeling frequency-domain photothermal experiments on multilayers

A general expression (master equation, ME) is derived for the thermal impedance in photothermal experiments in a multilayer system, based on one-dimensional (1D) periodic heat diffusion. The ME in a compact form benefits from newly defined generalized, higher-order thermal reflection and transmission coefficients. The modeled system comprises seven layers among which a semitransparent sample and a transducer that integrates the temperature field within it (e.g., a pyroelectric sensor). The ME can be adapted to various experimental cell structures used in photopyroelectric, photoacoustic, photothermal radiometry, or thermoreflectance methods using volume- or surface-temperature detection, in view of spectroscopic applications or thermophysical properties determination. The derivation of special cases is facilitated by applying simple contraction rules to dimensionless quantities. Modeling multiple heat sources in the system is done by superposition of individual solutions. The possible extension of the 1D model to 2D geometry is demonstrated, in general, and practical criteria are discussed.

Effect of protein content on the thermal effusivity of foods

Abstract The availability of thermophysical properties of both foods and their constituents is of considerable importance to the industry. The thermal effusivity is one of the less explored thermophysical parameters. It governs the penetration of heat into materials and is defined as the square root of the product of thermal conductivity of the material, volume-specific heat capacity, and density. This paper describes the application of a relatively new inverse photopyroelectric method (IPPE) to determine thermal effusivity of dehydrated whey protein isolate and egg white powder versus protein content. In both cases the effusivity values decreased linearly with increasing protein content. One percent increase in protein content of whey protein isolate and egg white lead to 6.5 and 7.2 Ws1/2 m−2 K−1 decrease in effusivity values, respectively.

Effect of Sunflower, Almond, and Rapeseed Oils as Additives on Thermal Properties of a Machinery Oil

Vegetable oils are considered to be eco-friendly and to offer good lubricant properties; however, their low thermo-oxidative stability makes their use as a lubricant base challenging. In this research, sunflower, almond, and rapeseed vegetable oils were added in volumes of 5, 10, 15, and 20% to a machinery oil, and the thermal properties of the resulting fluids were studied. Sunflower, almond, and rapeseed oils were chosen considering their fatty acid composition and the tocopherol content. During this investigation, thermal diffusivity was measured by using the thermal wave resonance cavity technique, while thermal effusivity was determined by the inverse photopyroelectric method, and the obtained values ranged from 4.63 to 5.75 Ws1/2m−2K−1 × 102. The thermal conductivity was calculated by obtaining a complete thermal characterization. The results showed a linear relationship between the percentage of vegetable oil and the thermal diffusivity. It was also noted that the thermal properties of diffusivity and effusivity could be tuned when using almond, sunflower, and rapeseed oils in the appropriate percentages. Hence, the influence of vegetable oils on the thermal properties of lubricating oil were closely related to the number of fatty acids.

Simultaneous thermal and optical characterization of semiconductor materials exhibiting high optical absorption by photopyroelectric spectroscopy

This work presents the results of the investigations on the thermal and optical properties of materials exhibiting high optical absorption. As test samples, some II-VI binary semiconductors were grown by using the Bridgman-Stockbarger method. The photopyroelectric (PPE) method, in two configurations (calorimetric and spectroscopic), was applied for both thermal and optical characterization of the specimens. The thermal diffusivity was obtained in the back detection configuration (BPPE) with an intensity-modulated laser as an excitation source. The same detection configuration, but with a tunable light source, provided information about the energy gap, the absorption coefficient, and the investigated sample's thermal diffusivity. The results obtained with these two methods were also compared with the data collected by conventional transmission and luminescence spectroscopies (absorption coefficient, energy gap). The main conclusion is the photopyroelectric spectroscopy (PPES) can provide in one measurement good quality information about the thermal and optical properties of the specimen.

Non-contact photopyroelectric approach for complete thermal characterization of porous building materials

The suitability of two photopyroelectric (PPE) methods for measuring the thermal diffusivity and effusivity of porous solids is described. The main characteristic of both methods, associated with the possibility of investigating porous solids, is the absence of coupling fluid between the pyroelectric sensor and sample. The first method (proposed initially by Salazar et al., Measurement 121, 96 (2018) [1]) relies on the front detection configuration with opaque pyroelectric sensor and thermally thick sample. Based on the phase frequency scan of the PPE signal, this method leads to the direct measurement of the sample’s thermal effusivity. The second method (proposed initially by Zammit et al., J. Appl. Phys. 117, 105,104 (2015) [2]) is based on two successive measurements (frequency scans), one in back and one in front PPE configuration, followed by a self-normalization of the phase vs. modulation frequency dependence. This method uses transparent pyroelectric sensor and backing material, allowing the direct measurement of the sample thermal diffusivity. In the paper, both methods were adapted and improved for investigating some porous building materials of interest: old bricks with unknown values of thermal parameters.

Growth and characterization of efficient second-order nonlinear optical material: N-(2-chlorophenyl)-(1-propanamide)

The crystals N-(2-chlorophenyl)-(1-propanamide) (NCP) appropriate for nonlinear optical (NLO) and electro–optic appliances were grown full-fledged by the slow cooling method. The solubility and metastable zone width range of NCP specimen were studied. The specimen crystallizes in the monoclinic crystal system with noncentrosymmetric space group of P21. The crystal morphology study also elucidates supplementary excellence of the as-grown NCP crystal. The optical precision in the whole visible region was found to be superior for NLO claim. The crystallinity of the full-fledged crystal is determined by etching and HRXRD. Laser harm threshold and photoluminescence studies delegate the grown crystal comprises extremely less imperfections. The mechanical deeds of NCP sample at assorted temperatures were examined to decide the hardness solidity of the grown specimen. The piezoelectric behavior and the comparative second harmonic generation for assorted particle sizes of the material were also deliberate. The third-order nonlinear ocular possessions of NCP crystal specimen were determined by Z-scan method. The optical homogeneity of the solitary crystal was assessed using customized channel spectrum technique. The thermal structures of NCP solitary crystal have been studied using photopyroelectric method. The half-wave voltage of the full-fledged crystal was intended from the electro–optic experimentation. Photoconductivity nature of the grown crystal outlined consummate inducing dipoles due to strong incident radiation and further revealed the nonlinear deeds of the grown material.

A photopyroelectric approach for electrocaloric effect characterization of polar materials

By means of the photopyroelectric method, we indirectly investigate the electrocaloric effect in polar materials by measuring the pyroelectric coefficient and the volumic heat capacity, as function of temperature. The influence of the heat capacity as function of the temperature on electrocaloric measurements is discussed. Measurements were performed on TriGlycine Sulfate single crystal. The compound showed a value of about 0.3 K upon a field change of 0.3 MV m−1 near it’s Curie temperature at 49 °C. Compared with repolarization current method where usually heat capacity is assumed as a constant value, the proposed technique provides an accurate way of calculating adiabatic temperature change of a ferroelectric material.

Self-normalized inverse photopyroelectric technique with viscous front window for thermal effusivity measurements in liquids

In this paper, the front detection (also called inverse configuration) photopyroelectric method for thermal effusivity measurement in liquids is improved by adding a viscous liquid to the front face of the pyroelectric sensor, on which the intensity modulated excitation light beam impinges, while the sample is attached to the rear side of the sensor. This viscous liquid will act as an optical transparent window. This configuration avoids problems related with the piezoelectric contribution to the photopyroelectric signal at high modulation frequencies that can be present in conventional approaches due to thermoelastic waves generated in the heated sample or by thermally induced deformations of the detector material itself. The theoretical and experimental principles behind the proposed method are presented and its usefulness is demonstrated with measurements on test samples.

Thermal Properties of Jojoba Oil Between $$20\,{^{\circ }}\hbox {C}$$ 20 ∘ C and $$45\,{^{\circ }}\hbox {C}$$ 45 ∘ C

Vegetable oils have been widely studied as biofuel candidates. Among these oils, jojoba (Simmondsia chinensis) oil has attracted interest because it is composed almost entirely of wax esters that are liquid at room temperature. Consequently, it is widely used in the cosmetic and pharmaceutical industries. To date, research on S. chinensis oil has focused on to its use as a fuel and its thermal stability, and information about its thermal properties is scarce. In the present study, the thermal effusivity and conductivity of jojoba oil between $$20\,{^{\circ }}\hbox {C}$$ and $$45\,{^{\circ }}\hbox {C}$$ were obtained using the inverse photopyroelectric and hot-ball techniques. The feasibility of an inverse photopyroelectric method and a hot-ball technique to monitor the thermal conductivity, and the thermal effusivity of the S. chinensis is demonstrated. The thermal effusivity decreased from 538 $$\hbox {W}\cdot \,\hbox {s}^{1/2}\cdot \,\hbox {m}^{-2}\cdot \,\hbox {K}^{-1}$$ to 378 $$\hbox {W}\cdot \,\hbox {s}^{1/2}\cdot \,\hbox {m}^{-2}\cdot \,\hbox {K}^{-1}$$ as the temperature increased, whereas the thermal conductivity remained the same over the temperature range investigated in this study. The obtained results provide insight into the thermal properties of S. chinensis oil between $$20\,{^{\circ }}\hbox {C}$$ and $$45\,{^{\circ }}\hbox {C}$$ .

A thermoelectrical parameter investigation using pyroelectric techniques: Application on Mylar

ABSTRACTThe pyroelectric methods have been recognized as a reliable and useful tool for the measurement of the thermoelectrical properties of Mylar layer. Using a new approach of theoretical models of photopyroelectric and electropyroelectric methods, it is possible to deduce thermal diffusivity, thermal conductivity, and electrical impedance of the given polyester film. The experimental results were found to be in agreement with the literature and the impedance analyzer values.

Evolution of elastic and thermal properties during TMOS-gel formation determined by ringing bottle acoustic resonance spectroscopy, impulsive stimulated scattering, photopyroelectric spectroscopy and the hot ball method

The evolution of the elastic and thermal properties of a tetramethylorthosilicate (TMOS)-based gel that exhibits an extraordinary ringing effect when enclosed in a bottle is investigated during the sol–gel transition. The results demonstrate the feasibility of three proposed experimental methods for monitoring of gels during their formation. The shear stiffening evolution during gelation is monitored by ringing bottle, resonant acoustic spectroscopy and by an ultrasonic technique using piezo electric excitation and detection. The evolution of the longitudinal modulus and the thermal diffusivity of the gel during stiffening are simultaneously determined by a combined photoacoustic and photothermal method based on heterodyne diffraction detection of impulsive stimulated scattering by, respectively, a propagating acoustic wave grating and a decaying thermal expansion grating that were both thermo elastically generated using a pulsed laser. Also, the feasibility of an inverse photopyroelectric method and a hot ball technique to monitor the thermal transport efficiency and thermal impedance of a forming gel by tracking the thermal conductivity, the thermal diffusivity, and the thermal effusivity is demonstrated. The network polymerization and stiffening during the sol–gel transition in TMOS-gel corresponds with substantial changes in the shear acoustic velocity and in all thermal properties, while the longitudinal acoustic velocity is only weakly affected.

Photothermoelectric (PTE) detection of phase transitions. Application to triglycinesulphate (TGS)

A recently introduced photothermal method, the photothermoelectric (PTE) calorimetry is proposed for the first time in order to detect phase transitions. The capability of both back (BPTE) and front (FPTE) detection configurations in detecting phase transitions is analyzed. It was found that the back detection configuration, with optically opaque sample and thermally thick sample and TE sensor, is very suitable for phase transitions detection; the information, in this configuration, can be collected from both amplitude and phase of the BPTE signal and the amplitude has the possibility of amplifying the critical anomaly of the thermal parameters. In the FPTE configuration, the information about phase transition is contained only in the amplitude of the signal. Using the PTE method, the well-known ferro-paraelectric phase transition of triglycinesulphate (TGS), tacking place at about 49°C, was investigated. Comparison with the photopyroelectric (PPE) method is performed.

Study of Thermophysical Properties of Silver Nanofluids by ISS-HD, Hot Ball and IPPE Techniques

In this work, the impulsive stimulated scattering technique, in a heterodyne diffraction detection configuration (ISS-HD), was used to study the dependence of the speed of sound and the thermal diffusivity on the concentration of silver nanoparticles in water, to which also d-glucose and carboxymethyl cellulose were added, in order to reduce sedimentation. The ISS-HD results, which show a slight increase of thermal diffusivity with increasing concentration, were cross-validated with results obtained by the inverse photopyroelectric method and the hot ball technique.

Thermal characterization of ZnBeMnSe mixed compounds by means of photopyroelectric and lock-in thermography methods

In this work, a thermal characterization (measurement of dynamic thermal parameters) of quaternary Zn1−x−yBexMnySe mixed crystals was carried out. The crystals under investigation were grown from the melt by the modified high-pressure Bridgman method with different Be and Mn contents. The effect of Be and Mn contents on thermal properties of Zn1−x−yBexMnySe compounds was analyzed, by using the photopyroelectric (PPE) method in the back configuration (BPPE) for thermal diffusivity measurements and the PPE technique in the front configuration for thermal effusivity investigations. Infrared lock-in thermography was used in order to validate the BPPE results. The measured thermal effusivity and diffusivity allowed the calculation of thermal conductivity of the investigated materials.

Alternative Calorimetry Based on the Photothermoelectric (PTE) Effect: Application to Magnetic Nanofluids

Photothermoelectric (PTE) calorimetry was applied for the first time for thermal characterization of liquids. Both back and front detection configurations, together with the thermal-wave resonator cavity (TWRC) scanning procedure, have been used in order to measure the thermal diffusivity and thermal effusivity of a particular magnetic nanofluid: carrier liquid—transformer oil, surfactant—oleic acid, nanoparticles’ type—\(\hbox {Fe}_{3}\hbox {O}_{4}\).The investigations were performed as a function of the nanoparticles’ concentration. Small increases of thermal diffusivity (from \(9.06\times 10^{-8}\,\hbox {m}^{2}{\cdot } \hbox {s}^{-1}\) up to \(9.84\times 10^{-8}\,\hbox {m}^{2}{\cdot } \hbox {s}^{-1})\) and thermal effusivity (from \(450\,\hbox {W}{\cdot } \hbox {s}^{1/2}{\cdot } \hbox {m}^{-2}{\cdot } \hbox {K}^{-1}\) up to \(520\,\hbox {W}{\cdot } \hbox {s}^{1/2}{\cdot } \hbox {m}^{-2}{\cdot } \hbox {K}^{-1})\) with increasing concentration of \(\hbox {Fe}_{3}\hbox {O}_{4}\) nanoparticles (from 0 up to 0.623 mg \(\hbox {Fe}_{3}\hbox {O}_{4}/\hbox {ml}\) fluid) were observed. The comparison with the photopyroelectric (PPE) method shows that PTE and PPE give similar results but, for the moment, PPE is more accurate.

Thermal characterization of II–VI binary crystals by photopyroelectric calorimetry and infrared lock-in thermography

In this paper, a complete thermal characterization (measurement of all static and dynamic thermal parameters) of some selected II–VI binary crystals was carried out. The semiconductors under investigation were grown from the melt by high-pressure/high-temperature-modified Bridgman method. The contact photopyroelectric (PPE) method in back configuration and non-contact infrared lock-in thermography technique were used in order to get the thermal diffusivity of the investigated crystals. The thermal effusivity of the samples was obtained using the PPE technique in the front configuration, together with the thermal wave resonator cavity method. Knowing the values of the thermal effusivity and thermal diffusivity, the remaining two thermal parameters, i.e., thermal conductivity and specific heat were calculated.

Thermal and Optical Characterization of Undoped and Neodymium-Doped Y3ScAl4O12 Ceramics

Y3–3xNd3xSc1Al4O12 (x = 0, 0.01, and 0.02) ceramics were fabricated by sintering at high temperature under vacuum. Unit cell parameter refinement and chemical analysis have been performed. The morphological characterization shows micrograins with no visible defects. The thermal analysis of these ceramics is presented, by measuring the specific heat in the temperature range from 300 to 500 K. Their values at room temperature are in the range 0.81–0.90 J g1–K–1. The thermal conductivity has been determined by two methods: by the experimental measurement of the thermal diffusivity by the photopyroelectric method, and by spectroscopy, evaluating the thermal load. The thermal conductivities are in the range 9.7–6.5 W K–1 m–1 in the temperature interval from 300 to 500 K. The thermooptic coefficients were measured at 632 nm by the dark mode method using a prism coupler, and the obtained values are in the range 12.8–13.3 × 10–6 K–1. The nonlinear refractive index values at 795 nm have been evaluated to calibrate the nonlinear optical response of these materials.

Characterization of thermal properties of Cd1−x−yZnxMgySe mixed crystals by means of photopyroelectric and infrared imaging techniques

Abstract In this work a complete thermal characterization of Cd 1− x − y Zn x Mg y Se mixed crystals was carried out. Bulk Cd 1− x − y Zn x Mg y Se semiconductors with different x and y contents were grown from the melt by the modified high pressure Bridgman method. The photopyroelectric (PPE) method in the back configuration (BPPE) and the infrared (IR) lock-in thermography were applied to measure the thermal diffusivity. Values of thermal effusivity of the samples were obtained with the PPE technique in the front configuration (FPPE), coupled with a thickness thermal wave resonator cavity (TWRC) scanning procedure. Measured thermal effusivity together with the thermal diffusivity allowed calculating the thermal conductivity of the investigated materials. For the calculation of the specific heat, the densities of the samples were calculated from their weight and geometry. The effect of Mg/Zn molar ratio on thermal properties of these quaternary Cd 1− x − y Zn x Mg y Se compounds was analyzed and discussed.

Bulk growth of ninhydrin single crystals by solvent evaporation method and its characterization for SHG and THG applications

Ninhydrin is a well-known compound generally used in amino acid synthesis and also for detecting the latent fingerprints on porous surfaces. Single crystals can be grown by dissolving the compound in double distilled water at ambient temperature, and can be used as a potential material for second and third harmonic generation applications. The grown specimen was subjected to different characterization techniques in order to find out its suitability for device fabrication. Its lattice dimensions have been confirmed by X-ray powder diffraction and its crystalline quality has been assessed by high resolution X-ray diffraction and X-ray topography methods. The presence of functional groups was identified from HETCOR analysis and confirmed the absence of impurities during crystallization. Its optical properties have been examined by photoluminescence and birefringence analyses. Its thermal parameters such as thermal diffusivity, thermal conductivity and specific capacity have been carried out by following photopyroelectric method. Third order nonlinear optical measurements have been carried out using Z-scan technique and its nonlinear optical absorption coefficient has been determined.