Dispersion Map Research Articles

Niobium-Tantalum Minerals Decipher Evolution of the Qiongjiagang Li-Rich Granitic Pegmatites in the Himalayan Orogenic Belt, Tibet

Abstract The Qiongjiagang giant pegmatite lithium deposit, located in the central section of the Himalayan orogenic belt, mainly comprises the spodumene-bearing pegmatite type, marginally accompanied by a petalite-bearing leucogranite dike and a lepidolite-bearing pegmatite. Existing uncertainties around the niobium (Nb) and tantalum (Ta) mineralization characteristics and their genetic ties among three types of Li-rich dikes justify further research. To enhance comprehension, backscattered electron imaging, energy dispersive spectrometry mapping, and electron microprobe analyses were employed. Microscopic features suggest that the Nb-Ta mineralization from Qiongjiagang spodumene-bearing pegmatite appears as the result of saturation of early magmatic columbite after lithium (Li) quenching arising from poikilitic spodumene crystallization. Subsequently, autometasomatism of hydrosilicate liquid caused partial dissolution of magmatic columbite as well as replacement of early primary minerals, forming fluid-induced Ta-rich overgrown and interstitial microcrystals (metasomatic columbite and pyrochlore) in microfractures. Muscovite crystallization and high Ta solubility may cause Nb-Ta element fractionation of individual zoned columbite and declining Nb/Ta ratios between discrete columbite and microcrystals. Both the continuous whole-rock compositional evolution from granite to lepidolite-bearing pegmatite and the gradual manganese (Mn) enrichment and titanium (Ti) decline of columbite geochemistry imply that the three types of dikes originated from three batches of sequential pulses of Li-rich magmas, demonstrated by progressive tourmaline or biotite fractionation of parent magma. The distinct Mn/Fe variation of columbite and whole-rock geochemistry also suggests that the three types of Li-rich magmas were already highly evolved in the upper part of their parental granitic magma chamber, instead of only fractionating once they escaped to the host rocks. Consequently, the textures and composition of columbite not only provide valuable insights into the magmatic-hydrothermal evolution of spodumene-bearing pegmatite, they also emphasize columbite's potential as a tracer for the degree of differentiation of magma.

A Facile Synthesis of Bimetallic Copper-Silver Nanocomposite and Their Application in Ascorbic Acid Detection

Background: An important antioxidant, ascorbic acid, must be detected in several industrial samples collected from food, pharmaceuticals, and water treatment plants. Herein, we reported a method to produce a bimetallic copper-silver (Cu-Ag) nanocomposite and used it in the development of very sensitive and selective electrochemical sensor for the detection of ascorbic acid. Methods: A simple chemistry concept was used during the synthesis process to reduce the cost while minimizing the use of dangerous chemicals and minimizing the environmental impact. The Strobilanthes kunthiana leaves extract effectively reduced the copper and silver ions, resulting in the creation of an extremely stable and evenly distributed Cu-Ag nanocomposite. Results: As-prepared bimetallic Cu-Ag nanocomposite exhibited outstanding electrochemical activity against ascorbic acid oxidation. The nanocomposite was examined using field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), elemental mapping (EMap) and X-ray diffraction analysis (XRD) to ascertain its composition, structure, and stability. Using cyclic voltammetry (CV), the electrochemical performance of the nanocomposite and also the detection of ascorbic acid were carried out. The bimetallic Cu-Ag nanocomposite also exhibited better long-term stability and fouling resistance, making it appropriate for use in real-world applications and complex sample matrices. Conclusion: The bimetallic Cu-Ag nanocomposite coated electrode was used to detect the concentration of ascorbic acid by amperometry. As a result, this study offered a simple chemical method for creating a bimetallic copper-silver nanocomposite with superior electrochemical qualities for the accurate detection of ascorbic acid.

Large-scale stellar age-velocity spiral pattern in NGC 4030

The processes driving the formation and evolution of late-type galaxies continue to be a debated subject in extragalactic astronomy. Investigating stellar kinematics, especially when combined with age estimates, provides crucial insights into the formation and subsequent development of galactic discs. Post-processing of exceptionally high-quality integral field spectroscopy data of NGC 4030 acquired with the Multi Unit Spectroscopic Explorer (MUSE) has revealed a striking grand design spiral pattern in the velocity dispersion map, that has not been detected in other galaxies. This pattern spatially correlates with HII regions, suggesting that stars currently being born exhibit lower velocity dispersion as compared to surrounding areas where star-formation is less active. We examined the age-velocity relation (AVR) and propose that its configuration might be shaped by a combination of heating mechanisms, seemingly consistent with findings from recent high-resolution cosmological zoom-in simulations. The complex structure of the uncovered AVR of NGC 4030 supports the hypothesis that stellar populations initially inherit the velocity dispersion sigma of the progenitor cold molecular gas, which depends on formation time and galactocentric distance, subsequently experiencing kinematic heating due to cumulative gravitational interactions during their lifetime. While advancing our understanding of the AVR, these findings also offer a new framework for investigating disc heating mechanisms and their role in the evolution of galactic discs.

Performance evaluation of developing electrical discharge machining tools through 3D-printed mould using selective laser sintering and expanding its applications in developing free-form tools

In the current study, an attempt has been made to find the optimum parameters for electroplating three-dimensional (3D) casted low melting point alloys. The electroplated profile is used as a tool in an electric discharge machining setup. A selective laser sintering process is used for 3D printing the mould in two halves. The mould parts are 3D scanned to find out the dimensional deviation. The low melting point alloy (LMPA) is cast in the mould. The surface roughness of the mould and the pattern are measured. Electroplating the casted LMPA sample is carried out in three stages in search of optimum parameters for getting stable copper deposits. The thickness of copper deposits under varying conditions is measured. The microstructures of cast alloys and copper deposits are analysed using a scanning electron microscope. The casted alloy and copper composition is verified through energy dispersive spectroscopy mapping and X-ray diffraction technique. The developed electric discharge machining electrode successfully performs the machining on the workpiece, and its performance is compared with that of a solid copper tool. The information gained is transferred to prepare the free-form tool using the developed path and is tested on the implant-shaped workpiece.

Optimized PVA-(ZnO)x-(PANI)1−x nanocomposites: characterization and humidity sensing application

This work presents an effort to study the potential of ternary PVA/ZnO/PANI nanocomposite for humidity sensing applications. Easily-peeled-off films of the ternary system were formed by the solution casting method and characterized. FTIR manifested the uniformity of the synthesized films and the existence of both polyaniline and ZnO functional groups in the relevant PVA host matrix. Characteristic absorption bands of PVA were overlapped with some characteristic bands of polyaniline. XRD patterns show the typical semicrystalline peak for the pristine PVA. The XRD analysis did not demonstrate any crystalline peaks for ZnO due to the capping-off effect of the PVA macromolecule. Energy dispersive X-ray mapping analysis and SEM micrographs manifested a homogeneous distribution of ZnO and PANI particles and a smooth yet dense film appearance. A study of electronic transitions and band gap displayed that the value of the band gap varies based on component concentration with the lowest value for the film of equal concentration of both ZnO and polyaniline. The humidity sensing behavior of the films was explored at different frequencies. The most variation in impedance was reached at 500 Hz, while the impedance variation at 50 Hz is the best from the performance point of view, where the relation between the impedance and relative humidity is linear. Samples F3 [PVA (ZnO)0.7(PANI)0.3], and F4 [PVA (ZnO)0.5(PANI)0.5] revealed the highest sensitivity among other tested samples. The measured hysteresis for the F3 and F4 samples were 1.38E + 05 MΩ/RH and 1.55E + 05 MΩ/RH, respectively. Impedance and complex impedance spectroscopy measurements confirmed that the film F3 revealed the highest sensitivity among the other tested samples. The proposed structure of the sensor can be employed for real-life applications since it can be easily coupled with electronic read devices and its overall functionality.

Chitosan functionalized recyclable and eco-friendly nanoadsorbent for Pb(II) adsorption from water

In the present study, MnO2 nanoparticles were synthesized using Citrus limetta peels extract and functionalized by chitosan polymer. Surface morphology analysis of chitosan functionalized MnO2 nanoparticles was carried out using a scanning electron microscope (SEM) and transmission electron microscope (TEM), which revealed that the synthesized nanoparticles were spherical, with a size range of 14–24 nm. Energy dispersive X-ray analysis and elemental mapping were used to observe Mn, O, C, H, and N. Fourier-transform infrared spectroscopy confirmed the presence of hydroxyl, carboxyl, and amino groups on the surface of the nanoparticles. The kinetics and isotherms were compared and it was found that the pseudo-second-order and Langmuir isotherm were the best fit, with R 2 values of 0.99. The thermodynamic study demonstrated that the adsorption was endothermic and spontaneous. These findings indicate that chitosan functionalized nanoparticles have a better Pb(II) removal efficiency (94.40%), making them an eco-friendly and cost-effective alternative for wastewater treatment. Highlights Chitosan functionalized nanoadsorbent was synthesized through green route. Sorption mechanism explored through isotherm, kinetics, and thermodynamic models. Synthesized adsorbent showed high Pb(II) removal capacity.

Redox-Targeting Semi-Liquid Electrode with Hard Carbon for High-Energy-Density Seawater Batteries

Seawater batteries (SWBs) are emerging as the next generation of energy storage systems owing to their high potential energy densities. However, they suffer from low practical energy densities. Utilizing an open-structured cathode that utilizes the unlimited supply of sodium ions from seawater, SWBs are inherently limited in energy density owing to the capacity of the anode. To maximize the amount of active material in a limited anode space, efforts with highly loaded electrodes present challenges in terms of sufficient reversibility, while liquid electrodes have low capacity, requiring alternative methods. To enhance the energy density of the SWB anode, this study used the “redox targeting” method, which has been used to enhance the energy density in redox flow battery systems. Redox targeting was achieved by combining a hard carbon (HC) active material with a sodium biphenyl (Na-BP) redox mediator in a semi-liquid electrode (SLE) form.Na-BP has a potential of approximately 0.09 V compared to sodium, while hard carbon has a reaction potential ranging from 0 V to 2 V. During the manufacturing process, the sodium source and electrons of Na-BP are transferred to hard carbon spontaneously. Morphological analysis of the HC in the synthesised SLE was carried out using scanning electron microscopy and energy dispersive spectroscopy elemental mapping, which showed that the sodium is uniformly distributed throughout the HC particles. During manufacturing, sodium and electrons were transferred effectively from Na-BP to HC.Ex-situ high-resolution transmission electron microscopy was used to confirm the structure of the HC of SLE after the charging and discharging process. The d-spacing between the graphite layers in the HC of SLE as-synthesis is approximately 3.7 Å, which is similar to the d-spacing of the pristine HC. However, the d-spacing of the HC after the SLE is fully charged increases to 4.3 Å. Conversely, the d-spacing of the hard carbon in the fully discharged SLE is reduced, similar to its initial as-synthesized state. In general, HC undergoes an intercalation reaction, causing an increase in d-spacing when sodium is stored between the layers of graphite. Sodium is reversibly intercalated and extruded into the HC of the SLE system.In a seawater battery half-cell system that uses a sodium ferrocyanide aqueous solution as the cathodic redox material, the electrochemical performance of the SLE during galvanostatic charge-discharge was compared with the theoretical voltage of 3.07 V. When operated at a current density of 10 mA gHC-1 (equivalent to 0.55 mA cm-2), the SLE showed a charging voltage of 3.2 V and a discharging voltage of 2.9 V. The cycling performance of the SLE was evaluated under various states of charge (SOC) at a current density of 20 mA gHC-1. The SLE demonstrated reversibility for 20 cycles with a capacity equivalent to 33.3 mAh cm-2 at an SOC of 100% and 75 cycles with a capacity equivalent to 22.2 mAh cm-2 at an SOC of 66.6%. The Coulombic efficiency was over 92.5%, and the energy efficiency was approximately 80%. Notably, the reversible capacity of 11.1 mAh cm-2 with a SOC of 33.3% was maintained for over 500 cycles, indicating the potential for over 5000 h of operation.After evaluating the electrochemical performance of the SWB half-cell system (using the sodium ferrocyanide catholyte), the SLE was applied to a full-cell system of the SWB via the oxygen evolution/reduction reaction (OER/ORR), which utilizes dissolved oxygen from natural seawater. At a current density of 10 mA gHC-1, the HCBP-SLE exhibited a charging voltage ranging from 3 V to 3.6 V and a discharging voltage ranging from 3.2 V to 2.5 V. The electrochemical performance was evaluated at a capacity of 33.3 mAh cm-2, which corresponds to an SOC of 100%, and exceeded 98.2% Coulombic efficiency and approximately 80% energy efficiency over 15 cycles. Therefore, it was confirmed that reversible operation with a high areal capacity is feasible even under natural seawater conditions.A semi-liquid electrode was produced utilizing an HC active material and an Na-BP redox mediator and then applied to seawater batteries. The semi-liquid electrode approach utilized a redox mediator to facilitate charge transfer, allowing energy storage in the active solid material. When applied to a SWB half-cell system, reversible operation for 20 cycles at an areal capacity of 33.3 mAh cm-2 and stable operation for more than 500 cycles (5000 h) at an areal capacity of 11.1 mAh cm-2 were demonstrated. These results can be employed to achieve high energy densities not only in seawater batteries but also in other battery systems, such as redox flow batteries or air batteries. Figure 1

Synthesis and characterization of low-density polyethylene (LDPE) bubble wrap-derived reduced graphene oxide for triboelectric nanogenerator electrodes

In this work, synthesis and characterization of reduced graphene oxide (rGO) as a triboelectric nanogenerator (TENG) electrode from waste low-density polyethylene (LDPE) bubble wrap is reported. The synthesized material is characterized for its morphology, structure and constituent elements via Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction (XRD), Energy dispersive spectroscopy (EDS), Elemental mapping and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques are used to test the performance of the fabricated rGO electrode. With specific capacitance retention of 85.8 %, energy density of 7.31 Wh Kg−1 and power density of 4.7 kW Kg−1, the electrode demonstrates strong capacitive behaviour. To investigate the practical application of the electrode, a TENG device is developed and tested for its electrical performance and a promising output potential of 411 mV is obtained by utilizing a PVDF-PZT separator. This work demonstrates a proof-of-concept for affordable alternate to convert the non-biodegradable waste in our surroundings into supercapacitor and TENG electrode.

Electrochemical template synthesis of hollow zinc oxide microtubes for photoelectrocatalytic water splitting: Effects of electrodeposition conditions and annealing temperature

In this paper, the problem of synthesizing hollow structures as a photoactive material for water electrolysis is addressed using the example of ZnO microtubes. In the study, a novel method of electrochemical template-assisted synthesis was applied to produce microtubes. The influence of zinc electrodeposition conditions (mode and electrolyte) and annealing on the photoelectrocatalytic (PEC) properties of the electrode material was evaluated. Samples prepared from citrate and zincate electrolytes were analyzed using scanning electron microscopy, energy dispersive X-ray mapping, X-ray diffraction, diffuse reflectance spectroscopy, photogalvanic response, voltammetry, and electrochemical impedance spectroscopy. The purpose of this paper was to demonstrate the advantages of using a citrate electrolyte over a classical zincate electrolyte for the electrochemical template method. It has been found that using citrate electrolyte allows for the production of ZnO microtubes that improve the PEC performance by 1.5–2 times. The effect of the synthesis conditions of the electrode material on the charge transfer resistance and diffusion limitations in the water splitting reaction is analyzed.

Structural, optical, and dielectric properties of double perovskite NdBaFeTiO6

NdBaFeTiO6 compound was synthesized successfully through solid-state reaction method. The compound was found to have a crystalline cubic double perovskite (DP) structure with space group Pm-3m by XRD analysis. Structural refinement was performed to investigate the detail of the structure and was found consistent with the experimental results. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and elemental mapping were used to analyze the morphology and elemental composition, revealing the existence of expected chemical composition and uniform distribution of elements within the material. FTIR and Raman spectroscopic techniques were utilized to investigate the vibrational modes and bonding configurations present in the synthesized sample. XPS spectra confirms the existence of photoelectron peaks associated with constituent elements, and also reveals the lattice oxygen and oxygen vacancies. Optical absorbance measurements showed that this material possesses a significant band gap energy of around 4eV, making it a promising candidate for a variety of technological applications. The electrical properties of this double perovskite were investigated using dielectric measurements, both frequency and temperature dependent. At low temperatures, the dielectric constant behaves independently. At higher temperatures, the thermal energy sufficiently enhances the mobility of charge carriers, thereby causing an elevation in dielectric constant of the order of 104 and 103 at low and high frequencies respectively. Moreover, the temperature dependence of the dielectric constant varies for different frequencies.

Advanced Kernel DM+V/W+ method for precise mapping of pollutant dispersion in indoor environments

This study introduces an advanced method for reconstructing pollutant concentration fields in indoor ventilated environments, aimed at enhancing air quality and ensuring occupant health. Our newly developed Kernel DM + V/W+ method significantly refines existing models by accurately capturing variations in pollutant dispersion in downwind areas while minimizing overestimations in upwind zones. This innovative approach overcomes the limitations of the traditional Kernel DM + V method, which neglects the impact of airflow, and the Kernel DM + V/W method, which inadequately differentiates between upwind and downwind dispersion. The effectiveness of this method is validated through a dataset derived from previously confirmed computational fluid dynamics (CFD) simulations across two standard indoor ventilation scenarios. A subset of this dataset was randomly selected for evaluation using the three methods, enabling a detailed performance analysis. The results demonstrate that the Kernel DM + V/W+ method markedly enhances accuracy in estimating concentrations at unsampled locations and significantly improves the identification of pollution sources, providing substantial benefits for environmental engineering applications.

Particle size and band gap evaluation of green gold nanoparticles (AuNPs) with potential applications

Abstract The present study was aimed towards green synthesis of gold nanoparticles (AuNPs) using fungal strain (SGSK-7) with assessment of their size using different techniques viz., X-ray diffractormeter, Dynamic light scattering, Atomic force microscopy, FE-Scanning Electron Microscopy and Fourier transform Infrared Spectroscopy. The intense characteristic diffraction peaks at angle 2Ѳ (38.13˚) presented the crystalline nature of the reduced gold solution and calculation of crystalline size (12 nm) using Scherer’s equation further confirmed synthesis of gold nanoparticles while dynamic light scattering analysis indicated the particle size range of gold nanoparticles between 2 nm to 50 nm. Field Emission Scanning Electron Microscopic (FESEM) and Atomic Force Microscopy (AFM) analysis of extracellular gold nanoparticles depicts spherical shape of AuNPs of approximately 40 nm. Fourier transform Infrared (FTIR) Spectroscopy depicted the presence of the gold nanoparticles along with the other biomolecules secreted by fungus which plays vital role in reduction, capping and stabilization of gold nanoparticles. Energy dispersive X-ray, mapping analysis, Zeta potential and UV-Vis spectrophotometery analysis further confirmed the presence and stability of gold nanoparticles, respectively. Zeta potential of gold nanoparticles leads to conclude the neutral nature (-10 mV to 10mV) of the particles. The UV-Visible spectrophotometeric analysis also confirmed the formation of gold nanoparticles with an absorption peak at 547 nm. On the basis of UV-Visible spectra the optical band gap of 2.44 eV is examined. The phylogenetic relatedness of SGSK-7 revealed 99% homology with Aspergillus tamari after sequencing of the ITS region followed by BLAST.

Investigation on electronic and magnetic properties of Cr doped V2O5 thin films prepared by chemical solution deposition method

The present study examines the role of Cr doping on the electronic and magnetic behaviour of V2O5i.e. V2-xCrxO5 (x = 0, 0.05, and 0.10) thin films, prepared by chemical-solution deposition technique on Si (111) substrate. X-Ray diffraction technique shows the purity of the films and confirms no secondary phase formation. The atomic force microscopy was used to confirm the roughness of the films. A morphological investigation is done using High-resolution scanning electron microscopy associated with Energy dispersive X-Ray mapping of each element of the film. Fourier transform Infrared spectroscopy is utilised to identify functional groups that are present in obtained samples. The band-gap of these obtained samples is in the range of 0.8–0.6 eV, as examined by UV–Vis i.e., its value is decreasing with Cr doping. Using vibrating sample magnetometer, it is clear that samples shows ferromagnetic (FM) behaviour with saturation magnetization 0.3–0.6 μB/cc consistent with Langevin function fitting. It concludes the presence of FM behaviour of films and magnetization increases with carrier density, consistent with the carrier-induced origin of the ferromagnetism. X-ray photoemission spectroscopy (XPS) is utilised to understand its electronic properties. Core level spectra measurements suggest that V is in mixed state of 5+ and 4+. However Cr is in 3+ states. XPS and UV–Vis measurements imply that oxygen vacancies significantly contribute to the declination of the band gap and the promotion of FM-like behaviour. This discovery offers a promising pathway for engineering novel devices.

Collapse of G+/G- bands, modification of Breit–Wigner–Fano signals and structural amorphization in single wall carbon nanotube networks under great excess of sulfur

The identification of superconductivity and ferromagnetic to superconductive transitions in sulfur-modified carbons has recently attracted an important attention. Additional work is however needed to better understand the structural modification of the graphitic interfaces in presence of sulfur. Here we report on an advanced methodology which involves soaking of large amounts (in the order of 500 mg) of sulfur through several annealing cycles into bundles comprising of hollow single-wall/few-wall carbon nanotubes (SWCNTs). TEM, HRTEM, XRD and Raman spectroscopy characterization analyses reveal the presence of structural amorphization of the SWCNTs, with dramatic impact on the intensity of the G+ and a progressive vanishing of the G- signal-contribution. We demonstrate the presence of high sulfur content by employing both point and mapping energy dispersive X-rays (EDX maps) acquisitions, with high local quantities of sulfur in the order of 16 %. Interestingly, a complex variation in the contribution of the Breit-Wigner-Fano (BWF) band, with appearance of extra D, G+ and C-S band-contributions, is revealed by deconvolution-analyses. The appearance of these structural features is a clear indicator of structural amorphization of the CNTs, with consequential formation of C-S hybrid structures, which we analyze systematically with the aid of energy dispersive X-ray spectrum mapping and Raman point/mapping spectroscopy approaches.

Exploration study of nickel slag/modified slag in the ultra-precision polishing of magnetic compound fluid

Nickel slag is the solid waste obtained from the nickel smelting process. Based on the magnetic elements in nickel slag, it is a potential ingredient that could be used in magnetic compound fluid (MCF) polishing. This work discusses polishing in MCF using nickel slag and modified slag. Investigations are conducted into how MCF is affected by the amount of modified slag and nickel slag present during polishing. The connections between shear force, position, material removal rate, morphological characteristics, and polishing quality are covered. Nickel slag is mixed with CaO, the alkalinity is adjusted, and the mixture is heated to 1500 °C to fully melt and oxidize it. The resulting product is modified slag. The morphological changes in MCF slurry before and after polishing were examined using an industrial camera, and the effect of different MCF slurry components on polishing performance was analyzed throughout the polishing process. In addition, the positioning of modified slag within the magnetic cluster formed during the polishing process was determined through a scanning electron microscope and by energy dispersive x-ray spectroscopy mapping of MCF slurry. The aforementioned research establishes the polishing mechanism for nickel slag and modified slag. The experimental results indicate that the polishing effect of the experimental group with added modified slag is better than that of added nickel slag. Under the same conditions, the surface roughness was reduced by 60% when modified slag was used instead of nickel slag. It was found that the optimal process is where the modified slag content is 10%, where the material removal rate is 1.207 × 108µm3/min and the surface roughness decrease rate is 95.482%. The polishing shear force is around 2.7N, which is twice as much as that of nickel slag.

Discovery of ~2200 new supernova remnants in 19 nearby star-forming galaxies with MUSE spectroscopy

Supernova feedback injects energy and turbulence into the interstellar medium (ISM) in galaxies, influences the process of star formation, and is essential to understanding the formation and evolution of galaxies. In this paper we present the largest extragalactic survey of supernova remnant (SNR) candidates in nearby star-forming galaxies using exquisite spectroscopic maps from MUSE. Supernova remnants (SNRs) exhibit distinctive emission-line ratios and kinematic signatures, which are apparent in optical spectroscopy. Using optical integral field spectra from the PHANGS–MUSE project, we identified SNRs in 19 nearby galaxies at ~100 pc scales. We used five different optical diagnostics: (1) line ratio maps of [S II]/Hα (2) line ratio maps of [O I]/Hα (3) velocity dispersion map of the gas; and (4) and (5) two line ratio diagnostic diagrams from Baldwin, Phillips & Terlevich (BPT) diagrams to identify and distinguish SNRs from other nebulae. Given that our SNRs are seen in projection against H II regions and diffuse ionized gas, in our line ratio maps we used a novel technique to search for objects with [S II]/Hα or [O I]/Hα in excess of what is expected at fixed Hα surface brightness within photoionized gas. In total, we identified 2233 objects using at least one of our diagnostics, and defined a subsample of 1166 high-confidence SNRs that were detected with at least two diagnostics. The line ratios of these SNRs agree well with the MAPPINGS shock models, and we validate our technique using the well-studied nearby galaxy M83, where all the SNRs we found are also identified in literature catalogs, and we recovered 51% of the known SNRs. The remaining 1067 objects in our sample were detected with only one diagnostic, and we classified them as SNR candidates. We find that ~35% of all our objects overlap with the boundaries of H II regions from literature catalogs, highlighting the importance of using indicators beyond line intensity morphology to select SNRs. We find that the [O I]/Hα line ratio is responsible for selecting the most objects (1368; 61%); however, only half are classified as SNRs, demonstrating how the use of multiple diagnostics is key to increasing our sample size and improving our confidence in our SNR classifications.

A novel high-brightness red phosphor Ca4Nb2O9: Eu3+ for WLEDs

In this study, new phosphors Ca4Nb2O9 doped with Europium (Eu3+) ions were created using a high-temperature solid-state method. Characterizations with X-ray diffraction (XRD), Rietveld refinement, scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS) and elemental mapping revealed successful doping and uniform elemental distribution. The band gap is 4.17 eV for Ca4Nb2O9 and 3.73 eV for Ca3.7Nb2O9: 0.3Eu3+, which is shown that the band gap decreases with increasing concentration. Subsequently, the samples underwent photoluminescence (PL) spectra testing, revealing that the Ca4Nb2O9: Eu3+ phosphors exhibited intense red emission when excited at 395 and 465 nm. Meanwhile, the principal emission peak resided at 613 nm, and the ideal doping concentration of Eu3+ was determined to be x = 0.3. In addition, at 420 K, the luminous intensity of Ca3.7Nb2O9: 0.3Eu3+ under 395 and 465 nm excitation is 60 % as well as 82 % of its strength at 300 K, respectively, indicating excellent thermal stability. Furthermore, the phosphor exhibits a relatively high quantum efficiency, reaching 45.47 % when excited with 395 nm light and 58.17 % when excited with 465 nm light. Finally, a white light-emitting diode (WLED) device with a Ra value of 86.3 and correlated color temperature (CCT) of 4450 K was fabricated. The results suggest that the prepared phosphor, in combination with a near-ultraviolet (NUV) light-emitting diode (LED) chip, has the potential for application in white light-emitting diodes.

Promising antibiofilm formation: Liquid phase pulsed laser ablation synthesis of Graphene Oxide@Platinum core-shell nanoparticles.

The increasing prevalence of multi-drug resistance in pathogenic bacteria has rendered antibiotics ineffective, necessitating the exploration of alternative antibacterial approaches. Consequently, research efforts have shifted towards developing new antibiotics and improving the efficacy of existing ones. In the present study, novel core shell graphene oxide@platinum nanoparticles (GRO@Pt-NPs) and their unchanging form have been synthesized using the two-step pulsed laser ablation in liquid (PLAL) technique. The first step involved using the graphene target to create graphene nanoparticles (GRO-NPs), followed by the ablation of GRO-NPs inside platinum nanoparticles (Pt-NPs). To characterize the nanoparticles, various methods were employed, including UV-VIS, transmission electron microscopy (TEM), energy dispersive X-ray (EDX), mapping tests, and X-ray diffraction (XRD). The anti-bacterial and anti-biofilm properties of the nanoparticles were investigated. TEM data confirm the creation of GRO@Pt-NPs. The average particle size was 11 nm for GRO-NPs, 14 nm for Pt-NPs, and 26 nm for GRO@Pt-NPs. The results demonstrate that the created GRO@Pt-NPs have strong antibacterial properties. This pattern is mostly produced through the accumulation of GRO@Pt-NPs on the bacterial surface of Klebsiella pneumoniae (K. pneumoniae) and Enterococcus faecium (E. faecium). The inhibition zones against K. pneumoniae and E. faecium when GRO-NPs were used alone were found to be 11.80 mm and 11.50 mm, respectively. For Pt-NPs, the inhibition zones of E. faecium and K. pneumoniae were 20.50 mm and 16.50 mm, respectively. The utilization of GRO@Pt-NPs resulted in a significant increase in these values, with inhibitory rates of 25.50 mm for E. faecium and 20.45 mm for K. pneumoniae. The antibacterial results were more potent in the core-shell structure than the GRO-NPs alone or Pt-NPs alone. The current work uses, for the first time, a fast and effective technique to synthesize the GRO@Pt-NPs by PLAL method, and the preparation has high clinical potential for prospective use as an antibacterial agent.

Biocomposite Scaffolds Based on Chitosan Extraction from Shrimp Shell Waste for Cartilage Tissue Engineering Application.

Chitosan-based scaffolding possesses unique properties that make it highly suitable for tissue engineering applications. Chitosan is derived from deacetylating chitin, which is particularly abundant in the shells of crustaceans. This study aimed to extract chitosan from shrimp shell waste (Macrobrachium rosenbergii) and produce biocomposite scaffolds using the extracted chitosan for cartilage tissue engineering applications. Chitinous material from shrimp shell waste was deproteinized and deacetylated. The extracted chitosan was characterized and compared to commercial chitosan through various physicochemical analyses. The findings revealed that the extracted chitosan shares similar trends in the Fourier transform infrared spectroscopy spectrum, energy dispersive X-ray mapping, and X-ray diffraction pattern to commercial chitosan. Despite differences in the degree of deacetylation, these results underscore its comparable quality. The extracted chitosan was mixed with agarose, collagen, and gelatin to produce the blending biocomposite AG-CH-COL-GEL scaffold by freeze-drying method. Results showed AG-CH-COL-GEL scaffolds have a 3D interconnected porous structure with pore size 88-278 μm, high water uptake capacity (>90%), and degradation percentages in 21 days between 5.08% and 30.29%. Mechanical compression testing revealed that the elastic modulus of AG-CH-COL-GEL scaffolds ranged from 44.91 to 201.77 KPa. Moreover, AG-CH-COL-GEL scaffolds have shown significant potential in effectively inducing human chondrocyte proliferation and enhancing aggrecan gene expression. In conclusion, AG-CH-COL-GEL scaffolds emerge as promising candidates for cartilage tissue engineering with their optimal physical properties and excellent biocompatibility. This study highlights the potential of using waste-derived chitosan and opens new avenues for sustainable and effective tissue engineering solutions.

MPC@But-SO3H a mesoporous heterogeneous organocatalyst in one-pot tandem synthesis of dihydroindeno[1,2-b]pyrrole derivatives

A sustainable, metal-free, and highly efficient protocol for the synthesis of dihydroindeno[1,2-b]pyrrole derivatives via a tandem one-pot three-component reaction in aqueous medium at room temperature using an effective and reusable mesoporous heterogeneous organocatalyst, MPC@But-SO3H has been developed. MPC@But-SO3H was easily synthesized using a melamine-based covalent organic polymer and 1,4-butane sultone. The organocatalyst was well characterized by numerous spectroscopic techniques such as Fourier Transform Infrared (FTIR), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), Powder X-ray diffraction (PXRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX), elemental mapping, and Thermal Gravimetric (TG) analyses. The catalyst displayed excellent catalytic potential, high thermochemical stability, and reusability for up to eight catalytic cycles. It offered the title compounds in excellent yields (˃90%) in a short reaction time (9-14 min). The synthesized compounds were characterized through FTIR, 1H, and 13C Nuclear Magnetic Resonance (NMR), and the molecular structure of 2-(benzylamino)-3a,8b-dihydroxy-1-methyl-3-nitro-3a,8b-dihydroindeno[1,2-b]pyrrol-4(1H)-one (4a) was confirmed by the Single Crystal XRD (SC-XRD) analysis. The key features of the present protocol include the use of water as a green solvent, zero involvement of any metal, sustainable reaction conditions, easy catalyst recovery, and a simple work-up procedure. The calculations for green metrics parameters further supported the greenness and sustainability of the protocol.