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

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.

Near-near-infrared thermal lens spectroscopy to assess overtones and combination bands of sulfentrazone pesticide

Thermal lens spectroscopy (TLS) in the near-near-infrared region was used to explore the absorptions of overtones and combination bands of sulfentrazone (SFZ) herbicide diluted in methanol. This spectroscopic region was chosen in order to guarantee that only thermal lens effect is noted during the experimental procedure. The results showed that it was possible to detect very low concentrations (~2ng/μL) of SFZ in methanol by determining its thermal diffusivity or the absorption coefficient due to the 3ν(NH)+1δ(CH) combination band. This minimum SFZ concentration is the limit observed by chromatography method. The findings demonstrated that the TLS can be used for precise and accurate assessment of pesticides in ecosystems. Besides, the 3ν(NH)+1δ(CH) combination band at 960nm can be used as a marker for SFZ in methanol.

Variations in fluorescence quantum yield of basic fuchsin with silver nanoparticles prepared by femtosecond laser ablation

Nano structured noble metals have very important applications in diverse fields such as photovoltaics, catalysis, electronic and magnetic devices, etc. In the present work, the application of dual beam thermal lens technique is employed for the determination of the absolute fluorescence quantum yield of the triaminotriphenylmethane dye, basic fuchsin in the presence of silver sol is studied. Silver sol is prepared by femtosecond laser ablation. It is observed that the presence of silver sol decreases the fluorescence quantum efficiency. The observed results are in line with the conclusion that the reduction in quantum yield in the quenching region is essentially due to the non-radiative relaxation of the absorbed energy. It is also observed that the presence of silver sol enhances the thermal lens signal which makes its detection easier at any concentration.