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The paper delineates the synthesis and development of zinc oxide (ZnO) hybrid nanofluids (HNFs) with different carbon sources (diesel soot (DS) and acetylene black (AB)) to address heat transfer (HT) limitations in thermal systems. Using a highly sensitive mode-mismatched dual beam thermal lens (MDTL) technique, the concentration-dependent thermal diffusivity modifications of the synthesized HNFs are monitored. The method of solution combustion is utilized for the synthesis of ZnO powder. The ZnO-hybrid composites are prepared by solid-state mixing and annealing of ZnO with DS and AB. The structure characteristics of the synthesized hybrid composites are understood through X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. The XRD and Raman analyses revealed the structural dislocations and the degree of disorder within the synthesized composites. The optical properties of the samples are revealed through ultraviolet-visible analysis. The MDTL investigation is carried out by preparing HNFs of the samples in ethylene glycol as the base fluid, thus elucidating the effect of lattice dislocations on the thermal behavior of the synthesized HNFs. Thus, the study suggests the potential of lattice dislocations-induced thermal diffusivity tuning ZnO-DS and ZnO-AB hybrid composites for various HT applications.

ABSTRACTDiversified technological applications necessitate the tailoring of morphology of materials at nanoscale. This paper reports morphological modifications of boron carbide (BC) at nanoscale through alkali (NaOH) treatment. The multilayered hollow microspheres of BC, obtained by the refluxion of castor oil with boric acid, are subjected to exfoliation by sonicating it in the ethanol–water mixture. The attractive morphologies evolved in the sonication process as a result of changing the BC concentration, auxiliary agent and sonication time are analysed. The multilayered hollow structure on sonication with NaOH yields flower-like morphology that seems to evolve from the basic spindle structure. The morphological tuning makes the study relevant in the areas like bleaching, where the surface area is crucial.

The paper reports the thermal-induced order fluctuations, in a carbon nanosystem with carbon nanotubes (CNTs) synthesized by the incomplete combustion of gingelly oil. The sample annealed at different temperatures (30–400 °C) is subjected to various morphological and spectroscopic characterizations. The ultraviolet–visible spectroscopic and thermogravimetric analyses reveal the CNTs in the sample. The high-resolution transmission electron microscopy (HR-TEM) also confirms the formation of CNTs in the sample. The Raman spectrum and X-ray diffraction pattern show the signature of multi-walled to single-walled CNT transformation and thus an order fluctuation on annealing. The quantum yield of the sample, measured by integrating sphere method, yields 46.15% at an emission wavelength of 575 nm. When the excitation wavelength is varied from 350 to 510 nm, the CIE coordinate moves from the white region to the yellowish-green region. The varying amount of CNTs in the soot, upon annealing is found to vary the luminescence emission from the sample. The study reveals the thermal-induced oscillatory order in carbon nanosystem with carbon nanotubes (CNTs) leading to tunable excitation/thermal-dependent luminescence emission and thereby suggesting the possibility of converting the futile soot for fruitful applications in photonics and nanoelectronics.

Photoacoustic technique has emerged as a powerful tool for nondestructive evaluation and characterization. The high signal to noise ratio, sensitivity, and the least quantity of sample required make the technique suitable for wide range of applications. The intensity modulated laser beam focused on to the sample in the photoacoustic cell generates acoustic waves. Analysis of the acoustic signal enables the measurement of thermal and optical properties of the material. In the present work, the photoacoustic technique has been extended to find the thermal diffusivity and to demonstrate how the technique can be used for measuring optical reflection coefficient of a precious metal mirror—Aranmula mirror. The mirror being metal with high reflection coefficient, it finds application in optical instrumentation. The mirror is subjected to morphological characterization by atomic force microscopy and field emission scanning electron microscopy. The elemental and structural characterizations are done by energy dispersive x-ray spectroscopy, X-ray dot mapping, and X-Ray diffraction analysis. The fractal dimension of the particle distribution over the surface provides information about the surface roughness. The box-counting and power spectral fractal dimensions are found to be around 1.63 and 1.65 respectively.

The photothermal phenomenon has emerged as a potential tool for the nondestructive evaluation of thermal and optical properties of materials. Thermal analysis of drugs is an unavoidable part of preformulation study, as temperature variations can induce structural changes of the constituents of drugs. Techniques based on photothermal phenomena are highly sensitive, as only the absorbed radiation contributes to the signal. Periodic illumination and subsequent nonradiative de-excitation generate thermal lens signals of various types within and around the sample. Variation of thermal diffusivity with a concentration of the commonly used drug terbutaline is studied through the single-beam thermal lens technique. The ultraviolet–visible spectrum of the drug shows strong absorption around 500 nm, which suggests the possible wavelengths that can be used for the study. It is found that concentration of the drug in liquid form decides its thermal stability, as its thermal diffusivity varies with concentration. The study gives information about the optimum value for the concentration of the drug noted above for which the chance of thermal stability is high.

Carbon nanoparticles (CNPs) have been explored widely in many fields of science and technology owing to its unique physical, chemical, mechanical, and biological properties. The interaction of the visible region of the electromagnetic radiation with plants and their role in photosynthesis is well studied. The antenna pigments in the protein matrix of thylakoid play a significant role in energy transport mechanism involved in photosynthesis. The energy absorbed by the proteins in the UV region also involves in the energy transport. The present work is aimed to understand the absorption of radiation by leaves in the ultraviolet (UV) region and the impact of CNPs produced by internal combustion diesel engines (ICE) in altering the absorbance level. The effect of CNPs is found to lower the UV absorbance by leaves and thus acting as UV shield, protecting the leaves from cell damages. The characterization of the CNP and leaves is done by field emission scanning electron microscope (FESEM) and UV-visible spectrophotometer.

Sugarcane (Saccharum specieshybrid) is one of the most important commercial crops cultivated worldwide for products like white sugar, bagasse, ethanol, etc. Red rot is a major sugarcane disease caused by a hemi-biotrophic fungus, Colletotrichum falcatumWent., which can potentially cause a reduction in yield up to 100%. Breeding for red rot-resistant sugarcane varieties has become cumbersome due to its complex genome and frequent generation of new pathotypes of red rot fungus. In the present study, a genetic linkage map was developed using a selfed population of a popular sugarcane variety CoS 96268. A QTL linked to red rot resistance (qREDROT) was identified, which explained 26% of the total phenotypic variation for the trait. A genotype–phenotype network analysis performed to account for epistatic interactions, identified the key markers involved in red rot resistance. The differential expression of the genes located in the genomic region between the two flanking markers of the qREDROTas well as in the vicinity of the markers identified through the genotype–phenotype network analysis in a set of contrasting genotypes for red rot infection further confirmed the mapping results. Further, the expression analysis revealed that the plant defense-related gene coding 26S protease regulatory subunit is strongly associated with the red rot resistance. The findings can help in the screening of disease resistant genotypes for developing red rot-resistant varieties of sugarcane.

To physiologically categorize drought tolerance characteristics of post-rainy sorghum [Sorghum bicolor(L.) Moench], 21 sorghum genotypes were evaluated under well watered and water deficit stress conditions for 2 years. Water deficit stress showed mixed effect among the genotypes for days to flowering, while other traits were adversely affected. Over 35 % reduction in grain yield was recorded due to post-flowering drought. Retention of green leaf area (GLA) during grain filling stage was found to be associated with drought tolerance. Loss of GLA started earlier and faster among high susceptible lines compared to tolerant lines. Based on stability analysis and drought susceptibility indices IS 23514 and Phule Chitra were identified as stable drought tolerant lines. Identified lines can be used in post-rainy sorghum breeding and molecular studies in future. The study also suggests that easily scorable physiological traits such as retention of green leaf area can be combined with stability analysis and DSI to identify drought tolerant genotypes.

This article proposes a unique approach to bring out the potential of graph-based features to reveal the hidden signatures of wet (WE) and dry (DE) cough signals, which are the suggestive symptoms of various respiratory ailments like COVID 19. The spectral and complex network analyses of 115 cough signals are employed for perceiving the airflow dynamics through the infected respiratory tract while coughing. The different phases of WE and DE are observed from their time-domain signals, indicating the operation of the glottis. The wavelet analysis of WE shows a frequency spread due to the turbulence in the respiratory tract. The complex network features namely degree centrality, eigenvector centrality, transitivity, graph density and graph entropy not only distinguish WE and DE but also reveal the associated airflow dynamics. A better distinguishability between WE and DE is obtained through the supervised machine learning techniques (MLTs)—quadratic support vector machine and neural net pattern recognition (NN), when compared to the unsupervised MLT, principal component analysis. The 93.90% classification accuracy with a precision of 97.00% suggests NN as a better classifier using complex network features. The study opens up the possibility of complex network analysis in remote auscultation.

A series of novel indanone chalcones were obtained regioselective mono derivatives by condensation of bis-aldehydes with indanone using potassium hydroxide as base. The newly synthesized chalcones were characterized using different analytic methods such as IR, 1HNMR, 13CNMR, mass spectrometry and elemental analysis. Results of antimicrobial screening evident that most synthesized derivatives were shows moderate to good activity against all tested organism.

•We propose a novel approach to distinguish croup cough (CC) and pertussis (PT).•The signature features of CC and PT are investigated using mathematical tools.•The complex airflow dynamics is unwrapped through nonlinear time series features.•FFT and fractal analyses helps to understand the internal morphology of air ways.•Cubic KNN and neural net pattern recognition are used for prediction.

A mammalian tooth is abraded when a sliding contact between a particle and the tooth surface leads to an immediate loss of tooth tissue. Over time, these contacts can lead to wear serious enough to impair the oral processing of food. Both anatomical and physiological mechanisms have evolved in mammals to try to prevent wear, indicating its evolutionary importance, but it is still an established survival threat. Here we consider that many wear marks result from a cutting action whereby the contacting tip(s) of such wear particles acts akin to a tool tip. Recent theoretical developments show that it is possible to estimate the toughness of abraded materials via cutting tests. Here, we report experiments intended to establish the wear resistance of enamel in terms of its toughness and how friction varies. Imaging via atomic force microscopy (AFM) was used to assess the damage involved. Damage ranged from pure plastic deformation to fracture with and without lateral microcracks. Grooves cut with a Berkovich diamond were the most consistent, suggesting that the toughness of enamel in cutting is 244 J m−2, which is very high. Friction was higher in the presence of a polyphenolic compound, indicating that this could increase wear potential.