Frequency-resolved photothermal lens: An alternative approach for thermal diffusivity measurements in weak absorbing thin samples

Cabrera, Humberto; Matroodi, Fatima; Cabrera-Díaz, Humberto D.; Ramírez-Miquet, Evelio E.

doi:10.1016/j.ijheatmasstransfer.2020.120036

Cited by 11 publications

(11 citation statements)

References 21 publications

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“…Because it was a purely resistive load (with Q = 0) the correction that results from the difference between true power value and this measured with PLC can be calculated with the Formula (12) and should be used in Formula (9) to get the corrected power depicted below in Figure 8.…”

Section: Sinusoidal Signals Of Voltage and Currentmentioning

confidence: 99%

“…Calculated power with Formulas (5) and 7without correction are depicted belo in Figure 7. Because it was a purely resistive load (with Q = 0) the correction that results from difference between true power value and this measured with PLC can be calculated the Formula (12) and should be used in Formula (9) to get the corrected power dep below in Figure 8. A comparison of values obtained with DAQ card and PLC measurement are list Table 4.…”

Section: Sinusoidal Signals Of Voltage and Currentmentioning

confidence: 99%

“…Comparing the results, it can be easily seen that in the case of sinusoidal signals, the delay in sampling between the voltage and current channels changes mainly the reactive power. However, this can be easily fixed with the correction given by Equation (12) or (13). additionally, the four-point sampling version does not differ much from the two-point version as smoothing can always be obtained by averaging two adjacent samples.…”

Section: Required Number Of Samplesmentioning

confidence: 99%

“…In the areas of intelligent construction and monitoring of building structures, with the help of low-frequency methods, measurements related to the physical-chemical parameters of buildings and thermal characteristics can be made [12].…”

Section: Introductionmentioning

confidence: 99%

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Low-Frequency Signal Sampling Method Implemented in a PLC Controller Dedicated to Applications in the Monitoring of Selected Electrical Devices

Jaraczewski

Mielnik

Gębarowski³

et al. 2021

Electronics

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High requirements for power systems, and hence for electrical devices used in industrial processes, make it necessary to ensure adequate power quality. The main parameters of the power system include the rms-values of the current, voltage, and active and reactive power consumed by the loads. In previous articles, the authors investigated the use of low-frequency sampling to measure these parameters of the power system, showing that the method can be easily implemented in simple microcontrollers and PLCs. This article discusses the methods of measuring electrical quantities by devices with low computational efficiency and low sampling frequency up to 1 kHz. It is not obvious that the signal of 50–500 Hz can be processed using the sampling frequency of fs = 47.619 Hz because it defies the Nyquist–Shannon sampling theorem. This theorem states that a reconstruction of a sampled signal is only guaranteed possible for a bandlimit fmax < fs, where fmax is the maximum frequency of a sampled signal. Therefore, theoretically, neither 50 nor 500 Hz can be identified by such a low-frequency sampling. Although, it turns out that if we have a longer period of a stable multi-harmonic signal, which is band-limited (from the bottom and top), it allows us to map this band to the lower frequencies, thus it is possible to use the lower sampling ratio and still get enough precise information of its harmonics and rms value. The use of aliasing for measurement purposes is not often used because it is considered a harmful phenomenon. In our work, it has been used for measurement purposes with good results. The main advantage of this new method is that it achieves a balance between PLC processing power (which is moderate or low) and accuracy in calculating the most important electrical signal indicators such as power, RMS value and sinusoidal-signal distortion factor (e.g., THD). It can be achieved despite an aliasing effect that causes different frequencies to become indistinguishable. The result of the research is a proposal of error reduction in the low-frequency measurement method implemented on compact PLCs. Laboratory tests carried out on a Mitsubishi FX5 compact PLC controller confirmed the correctness of the proposed method of reducing the measurement error.

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Section: Sinusoidal Signals Of Voltage and Currentmentioning

confidence: 99%

Section: Sinusoidal Signals Of Voltage and Currentmentioning

confidence: 99%

Section: Required Number Of Samplesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Low-Frequency Signal Sampling Method Implemented in a PLC Controller Dedicated to Applications in the Monitoring of Selected Electrical Devices

Jaraczewski

Mielnik

Gębarowski³

et al. 2021

Electronics

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show abstract

“…The photothermal spectroscopy comprises of a group of highly sensitive spectroscopic techniques such as the thermal lens (TL), photoacoustics, and photothermal beam deflection, which exploit the photothermal effects in the sample due to the heat generated by the photon absorption followed by non-radiative deexcitation [ 14 , 15 ]. Among these photothermal techniques, the TL spectroscopy detects the changes in refractive index temparature and density in the sample, to determine the thermo-optic properties including quantum yield [ 16 ], thermal diffusivity [ 17 ], and absorption coefficient [ 18 ]. There are various thermal lens experimental schemes for the determination of thermal diffusivity of transparent samples, among these the mode-mismatched dual-beam TL technique offers high accuracy, repeatability and sensitivity [ 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

Acclimatization through thermal diffusivity tuning of coconut oil – A mode mismatched dual-beam thermal lens study

Raj

Swapna

2022

Journal of Ayurveda and Integrative Medicine

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Background Ayurvedic medicinal oils traditionally prepared by blending herbal extracts in different compositions are commonly used for treatment and improving health. The estimation of the thermal properties of medicinal oils is essential for practical applications. Objective The present work aims to expound the ability of medicinal oils for the acclimatization of body temperature by determining its thermal diffusivity and thereby providing a validation to the traditional knowledge. Materials and methods The medicinal oils are prepared by incorporating black pepper ( Piper nigrum ), aloe vera ( Aloe barbadensis ), hibiscus bud ( Hibiscus rosa-sinensis ) and Ocimum sanctum in coconut oil base. The samples are subjected to thermal diffusivity study using the mode-mismatched dual-beam thermal lens technique. Results The study reveals that the incorporation of black pepper ( Piper nigrum ), having hot potency ( Ushna veerya ), to the base fluid lowers the thermal diffusivity value, suggesting its potential in heat-trapping. The addition of aloe vera ( Aloe barbadensis ), hibiscus bud (Hibiscus rosa-sinensis ), and O. sanctum dissipates heat energy quickly, thus increases the thermal diffusivity of coconut oil revealing a cold potency ( Sheeta veerya ). The study provides a validation for traditional knowledge and delineates the possiblity of thermal diffusivity tuning of the base fluids. Conclusion The thermal diffusivity tuning through incorporation of herbal extracts can effectively be used to acclimatize the human body temperature with the surroundings. A higher thermal diffusivity value induces a cooling effect and the lower value causes heating effect. This, opens up the possibility of using thermally tuned oils depending on climate and geographical location.

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Biosynthesis of Ag@Au bimetallic nanoparticles from Hymenaea courbaril extract (Jatobá) and nonlinear optics properties

Silva

Oliveira

et al. 2023

Journal of Molecular Liquids

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Frequency-resolved photothermal lens: An alternative approach for thermal diffusivity measurements in weak absorbing thin samples

Cited by 11 publications

References 21 publications

Low-Frequency Signal Sampling Method Implemented in a PLC Controller Dedicated to Applications in the Monitoring of Selected Electrical Devices

Low-Frequency Signal Sampling Method Implemented in a PLC Controller Dedicated to Applications in the Monitoring of Selected Electrical Devices

Acclimatization through thermal diffusivity tuning of coconut oil – A mode mismatched dual-beam thermal lens study

Biosynthesis of Ag@Au bimetallic nanoparticles from Hymenaea courbaril extract (Jatobá) and nonlinear optics properties

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