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Technological advancements in artificial intelligence (AI) have the potential to lead the way in promoting sustainable environmental practices as well as support environmental sciences and biodiversity field studies and research. The research will focus on designing an innovative system architecture that integrates laser-induced breakdown spectroscopy (LIBS) with a robust machine learning (ML) framework, significantly advancing sustainable environmental practices, especially since LIBS offers rapid and precise multi-elemental analysis, while AI enhances data processing and predictive capabilities. As technological innovations advance, the integration of the suggested LIBS system and advanced AI will be pivotal in addressing environmental challenges and promoting sustainability. This paper presents LIBS analytical data used to qualitatively assess soil constituents as a case study.

Heteropoly acids (HPAs) catalysts prove effective in waste cooking oil biodiesel production, considering their high density of Brønsted acidic sites, exhibit significant resilience to elevated levels of free fatty acid (FFA) and moisture content. However, the separation of HPA catalysts after biodiesel production is challenging due to their homogeneous catalytic nature. This study aims to develop magnetic vanadium-substituted HPAbased ZIF-8 composites to create a catalyst for biodiesel production from WCO that is more efficient and easier to separate. In this work, a range of analytical methods was utilized to characterize the catalyst, such as Fouriertransform infrared spectroscopy (FTIR), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), highresolution transmission electron microscopy (HRTEM), and a vibrating sample magnetometer (VSM). The successful incorporation of HPA acid into the magnetite ZIF-8 nanocomposite was indicated by prominent bands in the FTIR analysis, and this formation was further validated by EDX analysis. The VSM results also revealed that the nanocomposite has good magnetic responsiveness, facilitating catalyst separation and recycling. The magnetic ZIF-8 composites functionalized with H6PV3MoW8O40 demonstrated significant potential for sustainable biodiesel production from WCO.

Carbon quantum dots (CQDs) are fluorescent nanoparticles with diverse applications in multiple fields. The optical and physical properties of CQDs are influenced by several factors, such as the synthesis method, surface passivation and particle size. This study explores how carbon concentration affects the properties of CQDs. The CQDs were synthesized through a carbonization process with carbon concentrations varying from 0.03 to 0.15 g/ml. The samples of CQDs were characterized by using high resolution transmission electron microscopy (HRTEM), photoluminescence (PL) spectroscopy, zeta potential, dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FTIR). The results indicate that carbon concentration significantly impacts the optical properties and zeta potential of CQDs. Specifically, higher carbon concentrations result in increased fluorescence intensity and larger particle size. HRTEM images reveal that the average size of the CQDs is below 10 nm, consistent with DLS measurements. These findings suggest that carbon concentration can serve as a straightforward and effective parameter for tuning CQDs properties, with potential applications in bioimaging, sensing and optoelectronics. [ABSTRACT FROM AUTHOR]

Tin disulfide (SnS2) nanoparticles were synthesized via hydrothermal process and were deposited as ultrathin layer (27.5 nm) onto SLG via vacuum thermal evaporation. The SnS2 nanoparticles were characterized for their structural, purity, chemical, morphological, optical and electrical properties. The XRD patterns and the Raman spectra confirmed the successful synthesis of SnS2 nanoparticles. The stoichiometry and leaf like structure obtained from EDS and FESEM analysis of the SnS2 nanoparticles further proved its formation. The ultrathin layer deposited and annealed at 300 °C for 1 h showed XRD patterns of hexagonal structured SnS2 with crystallinity of 57.7 nm, bandgap energy of 2.7 eV and resistivity of 0.65 Ω cm. [ABSTRACT FROM AUTHOR]

Copper ions are one of the metal ions that contribute significantly to water pollution and threaten the ecosystem. The threat heightened the importance of the detection and removal of the contaminants. In this study, the Chitosan/Graphene Oxide (CH/GO) composite film was synthesized at different GO ratios via a direct casting technique. The structural, mechanical and film adsorption capacities were characterized along with the electrical properties. The results revealed that adding GO into CH at a 1:5 ratio produces the highest strength and adsorption capacity. The 1:5 film was then tested for its electrical properties to see the possibility of utilizing it as part of an electrical measurement system. Various electrical parameters such as permittivity (ε′, ε″), Tanδ, bulk resistivity (Rb) and DC conductivity (σDC) were studied. Results show that the 1:5 ratio chitosan film in various Cu2+ concentrations yielded significant differences in electrical properties. The Rb and σDC gave the most significant results and can be used as Cu2+ detection parameters. [ABSTRACT FROM AUTHOR]

Zinc oxide (ZnO) nanorods have attracted considerable attention in recent years owing to their piezoelectric properties and potential applications in energy harvesting, sensing, and nanogenerators. Piezoelectric energy harvesting-based nanogenerators have emerged as promising new devices capable of converting mechanical energy into electric energy via nanoscale characterizations such as piezoresponse force microscopy (PFM). This technique was used to study the piezoresponse generated when an electric field was applied to the nanorods using a PFM probe. However, this work focuses on intensive studies that have been reported on the synthesis of ZnO nanostructures with controlled morphologies and their subsequent influence on piezoelectric nanogenerators. It is important to note that the diatomic nature of zinc oxide as a potential solid semiconductor and its electromechanical influence are the two main phenomena that drive the mechanism of any piezoelectric device. The results of our findings confirm that the performance of piezoelectric devices can be significantly improved by controlling the morphology and initial growth conditions of ZnO nanorods, particularly in terms of the magnitude of the piezoelectric coefficient factor (d33). Moreover, from this review, a proposed facile synthesis of ZnO nanorods, suitably produced to improve coupling and switchable polarization in piezoelectric devices, has been reported. [ABSTRACT FROM AUTHOR]

Surface plasmonic sensors have received considerable attention, found extensive applications, and outperformed conventional optical sensors. In this work, biopolymer chitosan (CS) was used to prepare the bilayer structure (CS/Au) of a plasmonic refractive index sensor for dopamine (DA) detection. The sensing characteristics of the developed plasmonic sensor were evaluated. Increasing DA concentrations significantly shifted the SPR dips. The sensor exhibited stability and a refractive index sensitivity of 8.850°/RIU in the linear range 0.1 nM to 1 µM with a detection limit of 0.007 nM and affinity constant of 1.383 × 108 M−1. The refractive index and thickness of the CS/Au structure were measured simultaneously by fitting the obtained experimental findings to theoretical data based on Fresnel equations. The fitting yielded the refractive index values n (1.5350 ± 0.0001) and k (0.0150 ± 0.0001) for the CS layer contacting 0.1 nM of DA, and the thickness, d was (15.00 ± 0.01) nm. Then, both n and d values increased by increasing DA concentrations. In addition, the changes in the FTIR spectrum and the variations in sensor surface roughness and structure obtained by AFM analysis confirmed DA adsorption on the sensing layer. Based on these observations, CS/Au bilayer has enhanced the performance of this plasmonic sensor, which showed promising importance as a simple, low-cost, and reliable platform for DA sensing. [ABSTRACT FROM AUTHOR]

The temperature dependence of photoluminescence (PL) emission is a valuable tool for investigating carrier localization, recombination, and carrier–phonon interactions. Herein, electron–phonon couplings in lead sulfide (PbS) quantum dots (QDs) and lead sulfide/manganese tellurite (PbS/MnTe) QDs is reported. The effect of temperature on the PL emission of PbS and PbS/MnTe was explored within a temperature range of 10 to 300 K. When temperature increased, PL emission was blue-shifted due to the confinement effect. The gradual broadening of the full width at half maximum (FWHM) with increasing temperature indicates electron–phonon interactions. An analysis based on the Boson model revealed that the values of the exciton acoustic phonon coupling coefficient, σ, and temperature-dependent linewidth, γ, for PbS/MnTe were larger than those for PbS, indicating stronger exciton longitudinal-optical–phonon coupling in the compound structure. [ABSTRACT FROM AUTHOR]

Efficient shielding materials are extremely important to minimize the effect of electromagnetic interference. Currently, various composite materials are being investigated with different shielding efficiencies reported. In this paper, a flexible and free-standing sodium-based chitosan (CH/Na) polymer with copper selenide (CuSe) filler was prepared for electromagnetic shielding. The CH/Na/CuSe polymer matrix was prepared via the direct casting technique at different wt% of CuSe, varying from 2 to 20 wt%. The polymer matrix was then characterised by using Fourier transform infrared (FTIR) spectroscopy to confirm the interaction between the CH/Na and CuSe. The XRD results revealed that the CH/Na/CuSe polymer was successfully formed. Improvement in the electrical conductivity was confirmed by an impedance spectroscopy measurement. The highest electrical conduction recorded was at 3.69 × 10−5 S/cm for CH/Na/CuSe polymer matrix with 20 wt% CuSe. An increase in total electromagnetic interference (EMI) shielding efficiency (SET) of up to 20 dB (99% EM power shield) was achieved, and it can be increased up to 34 dB (99.9% EM power shield) with the thickness of the polymer increased. [ABSTRACT FROM AUTHOR]

Featured Application: Colloidal PbS quantum dots (QDs) that show a strong quantum confinement effect have potential towards photovoltaic application. Promising constant photoluminescence (PL) peak energies of PbS and PbS/MnS core shell QDs could be advantageous particularly for biological marker application. The quantum confinement effect and photoenhancement of photoluminescence (PL) of lead sulphide (PbS) quantum dots (QDs) and lead sulphide/manganese sulphide (PbS/MnS) core shell QDs capped with thiol ligands in aqueous solution were investigated. From PL results, the presence of MnS shells gives a strong confinement effect which translates to higher emission energy in PbS/MnS core shell QDs. Increasing MnS shell thickness from 0.3 to 1.5 monolayers (ML) causes a blueshift of PL peak energies as the charge carriers concentrated in the PbS core region. Enhancement of the PL intensity of colloidal PbS and PbS/MnS core shell QDs has been observed when the samples are illuminated above the band gap energy, under continuous irradiation for 40 min. Luminescence from PbS QDs and PbS/MnS core shell QDs can be strongly influenced by the interaction of water molecules and oxygen present in aqueous solution adsorbed on the QD surface. However, PbS/MnS core shell QDs with a shell thickness of 1.5 ML did not show a PL peak energy stability as it was redshifted after 25 min, probably due to wider size distribution of the QDs. [ABSTRACT FROM AUTHOR]

Free from scaling effect is highly desirable but yet challenging in lead-free BaTiO3 (denoted as BTO). In this work, we revisit the synthesis BTO nanocubes via hydrothermal route and provide an insight on the photoluminescence behavior of BTO nanocubes, whilst others focus on the reproducibility of BTO nanocubes. The crystallinity of the BTOs was enhanced when the as-synthesized powders underwent calcination at elevated temperatures (> 500 °C). A combination of X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM) images affirms that the BTO nanostructures evolved from cubic to tetragonal and changing from pseudo-ellipsoid to nanocube with {100} sharp facets. The tunable optical band gaps (3.18-2.74 eV), Urbach tails in UV-Vis absorption spectra and the enhanced intensity of photoluminescence at violet wavelength (433.7 nm) indicate the presence of localized state. In order to sort out the origin of the localized state, either stems from structural disorder or surface state, time-resolved photoluminescence was carried out. The long decay of the time-resolved photoluminescence (> 100 ns) proves the dominant involvement of self-trapped states. This in turn narrows the band gap, thus facilitates photoluminescence excitation. [ABSTRACT FROM AUTHOR]

In this work, frequency-dependent dielectric properties of polycrystalline samples with nominal compositions FeTeSe ( x = 0.0-0.5) were investigated. The samples were synthesized via solid-state reaction method with intermittent grinding at ambient pressure. The phase formation, lattice properties and chemical compositions of the samples were analysed. Dielectric constants ( $\varepsilon ^{\prime }$ , $\varepsilon ^{\prime \prime }$ ), dielectric loss (tan δ) and alternating current (AC) conductivity ( σ ) as a function of frequency ranging from 100 Hz to 10 MHz were measured at room temperature. X-ray diffraction (XRD) data showed the presence of impurity phases of FeO, FeTe and hexagonal FeSe/FeSe. Both a and c lattice parameters decreased with the substitution of Se. Energy-dispersive x-ray spectroscopy confirmed the increasing ratio of Se/Te with x. The measured negative values of real dielectric constant ( $\varepsilon ^{\prime } )$ for x = 0.0-0.5 indicate the conductive nature of these samples. As the Se content was increased, the $\varepsilon ^{\prime } $ became more negative as a result of better grain connectivity as shown by the higher AC conductivity and dielectric loss. [ABSTRACT FROM AUTHOR]

Polycrystalline samples with nominal composition FeTeS ( x = 0.00-0.30) were synthesized via solid state reaction method with intermittent grinding in argon gas flow. X-ray diffraction (XRD) patterns revealed the tetragonal structure (space group P4/nmm) of the samples with the presence of impurities FeO and FeTe. By substitution with S, the a and c lattice parameters shrink probably due to the smaller ionic radius of S compared to Te. Scanning electron microscopy images showed that the samples developed plate-like grains with increasing S substitution. Substitution of Te with S suppresses the structural transition of the parent compound FeTe as shown by both the temperature dependence of resistance and magnetic moment measurements. All of the S-substituted samples showed a rapid drop of resistance at around 9-10 K but zero resistance down to 4 K was not observed. In addition, negative magnetic moment corresponds to diamagnetism was detected in the samples for x = 0.25 and 0.30 suggesting the coexistence of magnetic and superconducting phase in these samples. The magnetization hysteresis loops measured at room temperature showed ferromagnetic behavior for the pure and S substituted samples. However, the magnetization, rentivity and coercivity decreased with S content. [ABSTRACT FROM AUTHOR]

In this study, polycrystalline samples with nominal composition FeTeSe ( x=0.1−0.5) were synthesized by solid-state reaction method at ambient pressure. In order to minimize oxidation, argon gas flow was maintained throughout the heat treatment. The phase formation of FeTeSe samples was checked by X-ray diffraction (XRD). The polycrystalline FeTeSe samples were indexed to a tetragonal structure with space group of P4/nmm. The lattice parameters a- and c-axes shrink significantly with the substitution of Se. As shown by the scanning electron microscope (SEM) images, the samples developed a plate-like grain structure gradually with the increase of Se concentration. Measurements of temperature dependence of magnetic moment showed that the onset of superconducting transition temperature, T, increased with Se concentration. The T is about 10.6 and 13.5 K for x= 0.1 and 0.5, respectively. All the samples exhibit ferromagnetic behavior asshown by the field-dependent magnetization measured at room temperature. [ABSTRACT FROM AUTHOR]

• Nickel-based metal organic framework (MOF) is used as a nonlinear material. • Nickel-based MOF/polydimethylsiloxane composite is spin-coated on a tapered fiber. • Encapsulation of the composite promotes better protection of tapered fiber waist. • The fabricated laser generates a fundamental soliton with good stability. This work demonstrates the fabrication of a saturable absorber with nickel 1,3,5-benzene-tricarboxylic acid (Ni-H 3 BTC)-metal organic framework (MOF) to generate soliton pulses in an erbium-doped fiber laser. The saturable absorber was fabricated by spin-coating Ni-H 3 BTC-MOF/polydimethylsiloxane composite on a tapered fiber as the encapsulation agent for light-matter interactions. The proposed cavity emitted a pulse laser at 1557.72 nm central wavelength with 3-dB bandwidth of 5.90 nm, pulse width of 907 fs, and average output power of 13.02 mW. At maximum pump power of 247.8 mW, the pulse energy was calculated to be 1.3 nJ at 10 MHz repetition rate. These results might assist as a footing to explore different types of available MOFs and their properties for the generation of ultrashort pulses. [ABSTRACT FROM AUTHOR]

Medical imaging phantoms are considered critical in mimicking the properties of human tissue for calibration, training, surgical planning, and simulation purposes. Hence, the stability and accuracy of the imaging phantom play a significant role in diagnostic imaging. This study aimed to evaluate the influence of hydrogen silicone (HS) and water (H2O) on the compression strength, radiation attenuation properties, and computed tomography (CT) number of the blended Polydimethylsiloxane (PDMS) samples, and to verify the best material to simulate kidney tissue. Four samples with different compositions were studied, including samples S1, S2, S3, and S4, which consisted of PDMS 100%, HS/PDMS 20:80, H2O/PDMS 20:80, and HS/H2O/PDMS 20:40:40, respectively. The stability of the samples was assessed using compression testing, and the attenuation properties of sample S2 were evaluated. The effective atomic number of S2 showed a similar pattern to the human kidney tissue at 1.50 × 10−1 to 1 MeV. With the use of a 120 kVp X-ray beam, the CT number quantified for S2, as well measured 40 HU, and had the highest contrast-to-noise ratio (CNR) value. Therefore, the S2 sample formulation exhibited the potential to mimic the human kidney, as it has a similar dynamic and is higher in terms of stability as a medical phantom. [ABSTRACT FROM AUTHOR]

A tunable spacing dual-wavelength Q-switched fiber laser is experimentally demonstrated based on a fiber Bragg grating tunable device incorporated in an erbium-doped fiber laser (EDFL). The system utilizes two identical fiber Bragg gratings (FBGs) at 1547.1 nm origin to enable two laser lines operation. The wavelength separations between two laser lines are controlled by fixing one of the FBGs while applying mechanical stretch and compression to the other one, using a fiber Bragg grating tunable device. The seven steps of wavelength spacing could be tuned from 0.3344 to 0.0469 nm spacing. Pulse characteristics for both close and wide spacing of dual-wavelength Q-switched fiber laser are successfully being recorded. The findings demonstrate the latest idea of dual-wavelength fiber laser based on FBG tunable device, which offers a wide range of future applications. [ABSTRACT FROM AUTHOR]

There are extensive studies on the development of composite solutions involving various types of materials. Therefore, this works aims to incorporate two polymers of nanocrystalline cellulose (NCC) and poly(3,4-ethylenethiophene) (PEDOT) to develop a composite thin film via the spin-coating method. Then, Fourier transform infrared (FTIR) spectroscopy is employed to confirm the functional groups of the NCC/PEDOT thin film. The atomic force microscopy (AFM) results revealed a relatively homogeneous surface with the roughness of the NCC/PEDOT thin film being slightly higher compared with individual thin films. Meanwhile, the ultraviolet/visible (UV/vis) spectrometer evaluated the optical properties of synthesized thin films, where the absorbance peaks can be observed around a wavelength of 220 to 700 nm. An optical band gap of 4.082 eV was obtained for the composite thin film, which is slightly lower as compared with a single material thin film. The NCC/PEDOT thin film was also incorporated into a plasmonic sensor based on the surface plasmon resonance principle to evaluate the potential for sensing mercury ions in an aqueous medium. Resultantly, the NCC/PEDOT thin film shows a positive response in detecting the various concentrations of mercury ions. In conclusion, this work has successfully developed a new sensing layer in fabricating an effective and potential heavy metal ions sensor. [ABSTRACT FROM AUTHOR]

The effect of NaOH solution on the formation of nanoparticles has been the subject of ongoing debate in selenium-based material research. In this project, the robust correlation between the mechanistic growth of zinc selenide/graphene oxide (ZnSe/GO) composite and the concentration of NaOH are elucidated. The ZnSe/GO composite was synthesized via microwave-assisted hydrothermal method and the concentrations of NaOH are controlled at 2 M, 3 M, 4 M, 5 M and 6 M. The XRD spectra show that the crystal phases of the samples exhibited a 100% purity of ZnSe when the concentration of sodium hydroxide (NaOH) was set at 4 M. The further increase of NaOH concentration leads to the formation of impurities. This result reflects the essential role of hydroxyl ions in modifying the purity state of ZnSe/GO composite. The optical band gap energy of ZnSe/GO composite also decreased from 2.68 eV to 2.64 eV when the concentration of NaOH increased from 2 M to 4 M. Therefore, it can be concluded that the optimum concentration of NaOH used in synthesizing ZnSe/GO composite is 4 M. This project provides an alternative green method in the formation of a high purity ZnSe/GO composite. [ABSTRACT FROM AUTHOR]

The compositions of 3 wt.% trivalent erbium ions (Er3+) doped zinc silicate (Zn 2 SiO 4) glass-ceramics was fabricated from waste materials via conventional solid-state method. From the XRD and FESEM results designate that the diffraction peaks of 3 wt.%Er3+:Zn 2 SiO 4 glass-ceramics improved with the heat treatment progression and homogeneously distributed in hexagonal and rectangular shapes. From UV–vis measurement, three detected peaks of optical absorption that corresponding to the optical transitions of Er3+ ions are located at 492 nm (4F 7/2), 524 nm (2H 11/2), and 650 nm (4F 9/2). The intensive sharp characteristic emission that correlated with Er3+ luminescence is resolved in photoluminescence spectra at room temperature and gives a yellow-green light colour emission at 559 nm under 385 nm excitation peaks. [ABSTRACT FROM AUTHOR]