Boron-doped graphene oxide (BG) nanoparticles were synthesized via nanosecond pulsed laser ablation of graphene flakes in ethanol, using boric acid as the boron source and a post-ablation strategy. Structural and elemental analyses (Raman, FT-IR, and XPS) confirmed graphene oxidation and successful boron incorporation. FESEM and HRTEM revealed spherical nanoparticles with an average size of 30-60 nm. Optical studies showed excitation-dependent bluish-green photoluminescence with enhanced intensity and a high quantum yield (5.30 %) due to boron doping, while time-resolved spectroscopy indicated an increased average lifetime (2.54 ns). Biocompatibility studies demonstrated low cytotoxicity toward T24 cancer cells, with boron-rich samples exhibiting particularly high photostability. Efficient cellular internalization and stable emission under biological conditions highlight the potential of BG nanoparticles as safe and effective bioimaging probes.

Fiber optic gas sensors have the advantages of room temperature sensing and their ability to detect gas at explosive and inaccessible locations. Nitrogen and boron co-doped graphene oxide (BNG) was synthesized efficiently and quickly by a single-step nanosecond pulse laser ablation (ns-PLAL) of graphene in ethanol. FT-IR and XPS confirm the nitrogen and boron doping on the surface of the graphene oxide (GO). The optical properties of BNGs were studied using UV-Vis analysis. FESEM confirms the spherical shape of BNG, and the average size of BNGs is 50–60 nm. Raman analysis was carried out on structural and crystallinity studies. The spherical-shaped BNG nanoparticle has been tested for sensitivity to room-temperature clad-modified fiber optic gas sensors with toxic gases like acetone, ammonia and ethanol. The gas sensing property of BNG was investigated using a fiber optic gas sensor, which was found to show good sensitivity and selectivity towards ethanol gas. The BNG nanoparticle demonstrates excellent characteristics for gas sensing due to its selective sensitivity and is a promising candidate for clad-modified fiber optic gas sensors.

Heteroatom-doped graphene oxide has a wide range of applications in bio-imaging and sensing. In this work, Graphene Oxide (GO) and Nitrogen-doped GO (NG) were synthesized by laser ablation of Graphene in ethanol. The dopant Diethylenetriamine (DETA) is used in different amounts for different nitrogen concentrations. Optical, morphological, structural, and elemental composition studies were done by UV–vis spectroscopy, FT-IR, FE-SEM, XRD, Raman, and EDAX analysis, respectively. The nitrogen doping on the surface of GO was confirmed by FT-IR and EDAX studies. Upon laser ablation with fundamental wavelength, the graphene is converted to spherical GO nanoparticles, and nitrogen doping is done to produce porous nano coral structured NG nanoparticles. The sensitivity and selectivity of GO and NG for ammonia, ethanol, and acetone target gaseous were investigated and compared. NG sample shows excellent sensitivity and selectivity towards acetone gas. And the Nitrogen-doped graphene oxide can be considered an ideal material for gas-sensing applications.

In this study, we present a plastic optical fiber for volatile organic compound (VOC) gas sensing, where a small portion of the cladding was replaced by CuO sensing material. The structural characterization of the CuO was assessed via powder diffraction X-ray analysis (XRD) and morphological analysis done by SEM imaging. For a variety of VOC gas concentrations, such as ammonia, ethanol, and methanol (0-500 parts per million), as well as for various lengths (1.5 cm and 3 cm) of sensing materials coated on the optical fiber, the spectrum properties of the CuO-coated fiber optic gas sensor were investigated. The 3cm coated CuO over the clad modified region of the plastic optical fiber showed highest intensity of fluctuation towards ammonia gas at wavelengths of 682, 753, and 926 nm, indicating that it is more sensitive to the gas and has a faster response and recovery rate at room temperature than the other two gases.

Underexplored Sm2O3, with tunable redox and high-surface nanostructures, emerges as a promising volatile organic compounds (VOCs) sensor material for next-gen applications. This study presents the successful synthesis of novel Sm2O3 luminescent quantum dots using a unique pulsed laser ablation technique. Material characterization by FESEM, XRD, EDAX, and HRTEM confirmed the formation of cubic polycrystalline quantum dots. The optical properties were studied by UV-Vis absorption and PL spectroscopy. These quantum dots were then employed in clad-modified fiber optic gas sensors operating at room temperature. Sensor response towards various VOCs, including acetone, ethanol, methanol, and ammonia, were evaluated. Ethanol displayed remarkable sensitivity and selectivity among the other, with a response of 104 x103 Counts/kPa at 25 degrees C for 500 ppm. Rapid response and recovery times of 48 and 55 seconds, respectively, further highlights the sensor's performance. These results establish Sm2O3 quantum dots as a promising and highly effective material for ethanol sensing.

Friction welding of tube-to-tube plate using external tool has earned prominent research interests due to its versatility and joint integrity. Hitherto, this process was studied primarily on the mechanical properties. This work presents the thermal studies of this process using analytical model and 3-D Finite Element Method-based numerical models. Infrared Thermography-based experimental temperature measurement has been done to verify the results in the case of AA 6061 plate and AA 1060 tube joints. Results for various parametric conditions show a good agreement with the corresponding FE simulation results. This study shows the temperature history of the process and explains the effect of frictional heat generation on the temperature attained by the material. With FE results, the internal temperature distribution of the material is explained. It is also revealed that tool rotation speed, plunge duration and total welding rotation strongly influence the peak temperature of the materials.

The impact of environmental pollution on climate change has necessitated the development of highly efficient gas sensors. Among the various sensing materials, metal oxides have shown great potential for gas sensing applications. However, the quest for highly efficient room-temperature gas sensors is ongoing. In this study, we present an approach for the fabrication of nanospheres from bulk TiO2 using the template-free pulsed laser ablation technique in liquids. The obtained nanoparticles were comprehensively characterized using X-ray diffraction, Raman analysis, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), ultraviolet–visible (UV–vis) spectroscopy, and photoluminescence (PL) studies to evaluate their structural, morphological, and optical properties. The room-temperature gas sensing performance of the fabricated TiO2 nanospheres (NTO) was evaluated using clad-modified fiber optic gas sensors for various gas concentrations. Remarkably, the NTO gas sensor exhibited interesting results, where the performance of NTO was twice that of its bulk counterpart, indicating its suitability for highly efficient gas sensing applications. Additionally, a theoretical calculation of light modulation through optical fibers was presented, providing insights into the sensing mechanism. Our findings demonstrate the potential of pulsed laser ablation in liquids for developing highly efficient room-temperature gas sensors for environmental monitoring applications.

Graphite oxide is prepared by laser ablation of Graphene in ethanol. FT-IR, Raman, TEM, and PL analysis have done. UV spectra shows π–π* transition of C=C and n–π* transition of C=O.

Thermal characteristics of ferrite nanoparticles are widely studied for magnetic nanoparticle hyperthermia, while alternative materials for the melioration of heating efficiency are being explored. We present the theoretical and experimental evaluation of (Fe, FeCo) core and iron oxide shell-based nanoparticles as potential materials for improved heating efficiency. The numerical computations reveal enhanced effective specific absorption rates up to 47 and 55 nH m2 kg−1 for Fe and FeCo core–shell particles (CSPs), greater than spinel ferrites, for varying shell thicknesses in the range of 2–10 nm. The experimental evaluation of the heating characteristics for the average particle sizes of 46 (Fe) and 18 (FeCo) nm has been probed using infrared thermography. The effective magnetic anisotropy constant determined from ferromagnetic resonance is 85 kJ m−3 for the FeCo CSPs that are larger than Fe CSPs and ferrites (15–23 kJ m−3). The temperature rise of 8 K observed for the FeCo CSPs is attributed to the partial compliance with the linear response theory suggesting it as a promising candidate for magnetic nanoparticle hyperthermia.

There is a significant demand for improved design and performance of gas sensors today. A fiber optic gas sensor based on light detection from a side-polished clad modified optical fiber (Evanescent mode) coated with nanocystalline aluminium oxide (Al2O3) is proposed for detecting VOCs such as acetone, methanol, ammonia, and ethanol gases. It is observed that there is an increase in the output light intensity for evanescent mode with an increase in the gas concentration, whereas a decrease in the transmission mode (light received from the end of fibre). The sensor exhibits excellent gas sensitivity and selectivity towards acetone gas in the evanescent mode. The normalized gas sensitivity for acetone was 603 x 10(-3) /kPa in the evanescent mode and 29 x 10-3 /kPa in transmission mode, which is about 20 times better at sensitivity in evanescent mode compared to transmission mode. The dynamic characteristics of the sensor were also studied. A theoretical model for light dynamics in the optical fiber during gas sensing and its correspondence with sensing mechanism has been discussed.

We investigate an organic nonlinear optical (NLO) crystal, (2-(2-hydroxy-3-methoxystyryl)-1-methylquinolinium-4-methylbenzenesulfonate (O-HMQ) suitable for Terahertz applications. The present study elaborates the synthesis, crystal structure, thermal stability and dielectric and transmission properties of O-HMQ crystal at terahertz frequencies. O-HMQ is successfully synthesized in our Laboratory. H-1-NMR and FTIR results revealed the molecular structure. O-HMQ single crystals of size 7 x 3 x 3 mm(3) are grown from methanol solution by solvent evaporation technique. Single crystal X-ray diffraction data shows that O-HMQ belongs to a monoclinic crystal structure with space group C 2/c. The melting point analysis shows a phase transition around 72 degrees C and a mesophase. The temperature-dependent dielectric study has been carried out for different frequencies ranging from 1kHz to 1 MHz proved the phase transition. The real part of the dielectric constant (epsilon(r)'), imaginary part (epsilon(i)'') and dielectric loss (tan delta) are estimated. Further, we demonstrate Terahertz (THz) transmission characteristics of our as-grown O-HMQ single crystal using 50 fs ultra-short two-color laser plasma source in a broad spectral range of 0.1-50 THz, proving its suitability for THz related applications. (C) 2021 Elsevier B.V. All rights reserved.

Pulsed laser ablation in liquid technique (PLAL) had started getting attention in late 1990, particularly for the production of the nanomaterials due to its easy handling and room-temperature synthesis process. Soon after the initial demonstration of nanomaterials generation from the PLAL technique, PLAL gradually becomes a green, facile and inexpensive method for the generation of ultrapure carbon nanomaterials (CNMs). In the past two decades, different allotropic forms of CNMs have been fabricated by using PLAL techniques such as graphene/graphene oxide nanosheet, carbon nanotubes, graphene oxide quantum dots, nanodiamonds, carbogenic nanoparticles, polyynes and carbon-encapsulated metal-based nanoparticles. In this review article, we offer a comprehensive discussion on the progress achieved in the design and development of the PLAL method for the production of CNMs only (the year 1998–2020). Firstly, we have introduced the different types of PLAL methods widely used for CNMs fabrication. Secondly, the different types of factors affecting the physicochemical (structural, morphological, optical) properties of CNMs and the efficiency of CNMs production from PLAL method have been summarized in detail. The laser parameters and experimental conditions of the PLAL method, that affecting the physicochemical properties and efficiency of CNMs production are laser wavelengths, pulse duration and repetition rate, ablation duration, per-pulse energy density (fluence), PLAL setup design and nature of solvents. The results from different spectroscopic techniques for each kind of CNMs have been discussed thoroughly, to unambiguously differentiate the structural integrity of  the CNMs from one another. Finally, the uses of CNMs for different applications in the present time, existing challenges in the PLAL methods and the future outlook of laser-assisted synthesized CNMs for novel applications were also discussed.

In this work, a simple nonenzymatic glucose sensor has been proposed based on coconut shell charcoal (CSC) modified nickel foil as working electrode in a three-electrode electrochemical cell. Charcoal was prepared by the pyrolysis of coconut shells. The most important advantages of coconut shells are cost-effectiveness and their abundance in nature. The morphology and phase of the CSC powder were characterized by scanning electron microscopy and X-ray diffraction. The electrochemical performance of the CSC powder coated Nickel foil electrode was investigated by cyclic voltammetry and chronoamperometry. The sensor shows a higher sensitivity of 2.992 mA cm−2 mM−1 in the linear range of 0.5–5.5 mM and slightly lower sensitivity of 1.1526 mA cm−2 mM−1 in the range of 7–18.5 mM glucose concentration with a detection limit of 0.2 mM. The anti-interference property of CSC powder also was investigated and found that the response of interfering species was less significant compared to glucose response. The proposed sensor offers good sensitivity, wide linear range, and a very low response to interfering biomolecules.

Traditionally, CNPs directly obtained from nanosecond pulsed laser ablation (ns-PLA) in an organic solvent like ethanol, isopropyl alcohol and acetone, possess toxic characteristics with excellent fluorescent properties. However, water-soluble CNPs are found to be non-toxic with weak fluorescent properties. In this study, a post ablation method was utilized to achieve water-soluble fluorescent CNPs. Initially, the colloidal Eth-CNPs solution was obtained from ns-PLA of charcoal powder in the ethanol, which was subsequently dried at room temperature and then dispersed in water to achieve the final water-soluble CNPs (W-CNPs). The High-resolution Transmission Electron Microscopy (HRTEM) image analysis of W-CNPs shows quasi-spherical size particle distribution with an average particle size found to be around 21 nm. XPS studies of charcoal powder and W-CNPs confirm the creation of fluorescent emissive defects state on the surface of W-CNPs under laser ablation in ethanol. Photoluminescence studies of W-CNPs demonstrated the wavelength-dependent PL emission, with peak PL emission in the blue region of the visible spectrum. In vitro studies indicated the non-toxic nature of the W-CNPs at low and high concentration (1, 5 and 10% v/v) in human cardiomyocytes. Herein, the W-CNPs obtained from post-ns-PLA was found to exhibit both blue and green fluorescence in the cardiomyocytes and hence, it can be exploited as a fluoro probe in bioimaging applications.

Bismuth tungstate (Bi2WO6) nanomaterials were synthesized through hydrothermal method. XRD and SEM studies on synthesized nanomaterials showed crystal structure as orthorhombic phase and surface morphology as nanochips with rectangular shape, respectively. As prepared bismuth tungstate nanoparticles were used to modify a portion of the cladding of PMMA optical fiber and their gas sensing characteristics were studied at room temperature for various concentrations (ppm) of ammonia, ethanol, and methanol. The gas sensor exhibited good response to methanol. (C) 2021 Published by Elsevier B.V.

This communication reports multiferroic perovskite, nano crystallite BiFeO3 coated clad modified PMMA Fiber optic sensor functioning at room temperature and sensing Toxic gas in the environment. The porous BiFeO3 nanocrystalite clusters synthesized through solvothermal process and its structure, composition and morphology are analysed using XRD, EDAX and SEM. The crystallites were in agglomerated dimensions with pores up to 500 nm, average particle size 30 nm with rombohedral crystal structure. And it is used in the Fiber optic sensor modifying the original PMMA clad. Spectral response for BiFeO3 clad modified sensor is observed for Ammonia, Ethanol and Methanol, and the better sensitivity is found for Ammonia at room temperature compared to the other two vapours ethanol and Methanol. (C) 2020 The Authors. Published by Elsevier Ltd.

Magnetite nanoparticles are extensively studied for their applications in magnetic nanoparticle hyperthermia. However, existing methods involve invasive methods for monitoring the thermal profile while the heat generated by the magnetite nanoparticles is utilized for cancer therapy. Tumor diagnosis utilizing thermography for monitoring the thermal profile is in the early stage of development since the temperature sensitivity is influenced by various experimental factors. Magnetite nanoparticles embedded in agar matrix which mimics the human tissues and their heating characteristics were investigated using infrared thermography. The magnetite nanoparticles with an average particle size of 10[Formula: see text]nm were subjected to heating in an applied frequency of 500[Formula: see text]kHz. The influence of concentration, area and depth on the heating characteristics of the tumor phantoms were deduced from the thermography images. The parameters that influence the therapeutical sensitivity while using infrared thermography for magnetic nanoparticle hyperthermia, have been studied for potential applications in theranostics.

To fabricate efficient gas sensors with novel engineered nanomaterials, silver nanoparticles (Ag-NPs) were successfully green synthesized by Nd: YAG nanosecond pulsed laser ablation technique using a mixture of diluted silver nitrate solution and citrus limetta juice extract irradiated for different ablation durations at room temperature. Brownish-yellow colloidal Ag-NPs formation was confirmed by UV-Vis spectroscopy with the absorbance peak around 407-419 nm. HR-TEM results confirmed well mono-dispersed spherical shape morphology for Ag-NPs with particle size around 8 nm for near to 80 min of ablation time. Notably, the engineered nanostructured Ag-NPs were used freshly in room temperature fiber optic gas sensing. The sensor exhibited an outstanding linear response for ammonia gas (0-500 ppm). The sensitivity was about 128.7 Counts/kPa for ammonia gas at RT. The dynamic response of the sensor was recorded to be 15.5 s and 3.5 s. In summary, laser-ablated green synthesized Ag-NPs showed excellent efficiency in detecting ammonia gas at room temperature.

In this report, silver nanoparticles (Ag-NPs) were prepared by pulsed laser ablation of the silver nitrate salt solution using Nd:YAG laser. Trisodium citrate (TSC) is used as a stabilizing/reducing agent for nanoparticles. Under different laser ablation durations, the morphology of nanoparticles changed. Nanoparticles showed the average size ranging from 5 to 31 nm for 20–80 min of ablation. The theoretical and experimental estimation of the particle sizes is done. Butterfly-shaped silver nanoparticles have been tested for the room-temperature clad-modified fiber optic gas sensors sensitivity with ammonia and ethanol gas. The clad-modified optical fiber sensor exhibits distinct linear variation in the spectral peak intensity with the ammonia concentration (0–500 ppm). The characteristics of the gas sensors when exposed to ethanol and ammonia gases were used for studying the sensor selectivity. The results exhibited good sensor response and selectivity for ammonia with sensitivity of 64 counts/ppm and sensitivity percentage of 27%, whereas for ethanol, sensitivity of 9.5 counts/ppm and sensitivity percentage of only 4% were observed.