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Perovskite oxide BaNi0.5Mn0.25Fe0.25O3 was successfully synthesized using a sol–gel method. Structural refinement analysis has been performed to investigate the details of the crystalline structure which was found to be a rhombohedral system at room temperature with the space group R 3 ¯ C . Crystallite size, lattice strain, density and porosity parameters were also calculated. The morphology and the elemental composition were analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Raman scattering spectroscopy has been performed in order to study the vibrational modes and the various bond formations of the synthesized sample. The study of the magnetic properties shows a ferro-paramagnetic transition (FM–PM) at the curie temperature. The electrical behavior of this double perovskite was also studied using complex impedance spectroscopy. Electrical conduction follows Jonscher's power law, and the conduction mechanisms are identified. The variations of the real and imaginary parts of impedance according to the frequency and temperature show the presence of a relaxation phenomenon in the sample, and it is thus a potential candidate for various technological applications in microelectronics and energy storage. [ABSTRACT FROM AUTHOR]

This work investigates the effect of band structure, optical spectra, computed elastic coefficients, Bulk-to-Shear modulus ratio, Young's modulus and Poisson's ratio in metal selenide compounds and their influence on electronic, optical, and elastic properties of bulk crystals using density functional theory (DFT). By studying the structural and geometrical parameters, we show that the V–VI group compound has a direct bandgap of 0.887 eV and the band structure can be explained by a partial density of states (PDOS) plot. By using Pugh's formation, the bulk-to-shear ratio can be significant in precisely determining the ductility of a material. Poisson's ratio can provide information to examine whether the lattice crystal is ionic or covalent. Our elastic data show that the orthorhombic system is found to be unstable. The optical spectra (high absorption coefficient of 1. 7 8 × 1 0 5 cm − 1 , dielectric coefficient of 8.61 and reflective index of 2.93) of our current work would be beneficial to explore the applications of optoelectronic devices, especially in light-harvesting materials, covering the UV region. Our findings advance the knowledge of the structural, electronic, optical, vibrational, and mechanical properties of Sb2Se3, the key to their use, and explained the potential applications in photovoltaics perspectives. [ABSTRACT FROM AUTHOR]

The use of composite materials has seen widespread adoption in modern aerospace industry. This has been facilitated due to their favourable mechanical characteristics, namely, low weight and high stiffness and strength. For broader implementation of those materials though, the out-of-autoclave production processes have to be optimized, to allow for higher reliability of the parts produced as well as cost reduction and improved production speed. This optimization can be achieved by monitoring and controlling resin filling and curing cycles. Photonic Integrated Circuits (PICs), and, in particular, Silicon Photonics, owing to their fast response, small size, ability to operate at higher temperatures, immunity to electromagnetic interference, and compatibility with CMOS fabrication techniques, can offer sensing solutions fulfilling the requirements for composite material production using carbon fibres. In this paper, we demonstrate a passive optical temperature sensor, based on a 220 nm height Silicon-on-Insulator platform, embedded in a composite tool used for producing RTM-6 composite parts of high quality (for use in the aerospace industry). The design methodology of the photonic circuit as well as the experimental results and comparison with the industry standard thermocouples during a thermal cycling of the tool are presented. The optical sensor exhibits high sensitivity (85 pm/°C), high linearity (R2 = 0.944), and is compatible with the RTM-6 production process, operating up to 180 °C. [ABSTRACT FROM AUTHOR]

The citric-nitrate technique was used to synthesize polycrystalline Nd 2 Ni 1-x Co x MnO 6−δ (0.2 ≤ x ≤ 0.5) perovskite oxide. Phase formation was studied by X-ray powder diffraction (XRPD). The unit cell parameters and unit cell volume were refined by the Rietveld analysis, increase with the increasing doping concentration of cobalt. The optical study was performed for the samples in the range of 200–800 nm using UV–vis spectroscopy an absorption peak has been observed in around 330 nm. The energy bandgap (E g) of the studied samples is slightly influenced by the increasing concentration of cobalt due to the interaction of electronic states between doped Co and other 3d metals. Partial substitution of nickel by cobalt at B-site decreases the Curie temperature (T C) and increased the irreversibility between the zero-field cooled (ZFC) and field-cooled (FC) below T C. The decreasing tendency of T C for the studied samples with the increasing concentration of cobalt in Nd 2 Ni 1-x Co x MnO 6−δ might be associated with the decreasing Ni/Co–O–Mn bond angle. [ABSTRACT FROM AUTHOR]

Fused silica glass, in particular, offers a broad range of applications in optics. The present study investigates fused silica samples using non-conventional medium-pressure plasma polishing at optimum machining parameters. The polishing parameters, i.e. gas composition (He: (SF6+O2)) of 90:10, pressure ratio (SF6:O2) of 1:1, total pressure of plasma chamber of 5 mbar, and radio-frequency (RF) power of 80 W have been obtained at optimum parametric conditions. The highest material removal rate of 100.36 × 10−3 mm3/min is achieved at optimized process conditions. Even though the surface finish is slightly degraded from 0.28 µm to 0.30 µm, without any surface contamination as analyzed by the 3D optical profiler and Energy-Dispersive X-ray (EDX). Moreover, EDX analysis reveals the presence of fluorine elements after plasma processing, confirming the plasma's interaction with the substrate. Furthermore, Raman spectroscopy results show a maximum 13% reduction in damaged and strained layers after plasma processing on the machined surface.. [ABSTRACT FROM AUTHOR]

Starch materials are subject to loss of initial characteristics due to the retrogradation degenerative effect, high hygroscopicity, and favoring the growth of the microorganisms, which reduces the shelf life of packaging. In this sense, the insertion of nanoparticulated CuO was evaluated for the best performance. CuO is a semiconductor that can improve optical, mechanical, and antimicrobial properties, enabling excellent promotion of starch films. The hot injection precipitation method was used to obtain CuO nanoparticles in the nanometric scale rapidly. The films were carried out from the starch homogenization in water and urea under temperature, followed by thermopressing at 120°C. As a result, the 1% CuO (w w−1) increased tensile strength from 0.87 ± 0.40 to 1.92 ± 0.09 MPa. Furthermore, the films containing nanoparticles showed a barrier property against radiation in the ultraviolet–visible spectrum, not observed for the micrometric scale. Such results were attributed to the superior opacity of the films generated by nanometric reinforcement. Concerning antimicrobial activity, the films containing CuO showed a fungistatic effect (33%) for the Alternaria alternata fungus, a microorganism very susceptible to carbohydrate‐rich sources. Thus, the CuO‐reinforced starch films improved physicochemical and biological properties, making them promissory candidates for commercial application. [ABSTRACT FROM AUTHOR]

The structural, electronic, magnetic, and optical properties of Au, Cu, Cr, Mn, Co, Ni, and Fe atoms doped 13-atom silver clusters were investigated by the density functional theory (DFT) in the theoretical frame of the generalized gradient approximation (GGA) exchange-collection function. The results show that all the ground state structures of Au, Cu, Cr, Mn, Co, Ni, and Fe atoms doped 13-atom silver clusters are icosahedral, respectively. The Au atom doped on the surface of Ag 1 3 cluster is stable, while other atoms doped in the center of Ag 1 3 cluster are stable. The electronic stability order from high to small is Ag 1 2 Cr1, Ag 1 2 Cu1, Ag 1 2 Co1, Ag 1 2 Fe1, Ag 1 2 Au1, Ag 1 2 Mn1, Ag 1 2 Ni1. Their magnetic moments are not only related to the doping atom but also the doping location of the atom. The magnetic moments of the Cu, Au, Mn, Co, Ni, Fe, and Cr atoms doped in the Ag 1 3 cluster are 5.0, 3.0, 1.0, 3.0, 4.0, 2.0, and 0.0 μ B , respectively. Compared with the optical absorption spectrum of the Ag 1 3 cluster, the Au, Cr, and Mn atoms doped the Ag 1 3 cluster leading to blue shift, and the Cu, Co, Ni, and Fe atoms doped the Ag 1 3 cluster resulting in red shift. These studies provide a theoretical basis on applications for clusters in electronic, magnetic, and optical devices. The Au atom doped on the surface of the Ag13 cluster is stable. In contrast, other atoms doped in the center of the Ag13 cluster are stable. Ag13 clusters doped by Cu and Cr atoms increase the chemical stability, whereas Ag13 clusters doped by Au, Mn, Co, Ni, and Fe atoms decrease the chemical stability. [ABSTRACT FROM AUTHOR]

Autonomous cislunar spacecraft navigation is critical to mission success as communication to ground stations and access to global positioning system (GPS) signals could be lost. However, if the satellite has a camera of sufficient quality, geometric line-of-sight (unit vector) measurements can be made to known lunar landmarks (e.g., Tycho Crater) to provide observations that enable autonomous estimation of the position and velocity of the spacecraft. In this study, an improved batch gaussian initial orbit determination (IOD) differential corrector (DC) algorithm, based on the approximated values of the two-body f and g series, is applied to initialize a (non-conic based) circular restricted three body problem (CR3BP) extended Kalman Filter (EKF) navigator. This navigator collects geometric line-of-sight unit vector (angle only) measurements to a known location on the Moon to sequentially estimate the position and velocity of an observer spacecraft flying on an approximate southern L1 Halo orbit. In this study, it was found that the best approach is to initialize the CR3BP EKF (navigator) using the solution from the batch DC filter with at least 10 measurements taken against the perceived centroid of Tycho Crater. Thereafter, it is best to continue the navigator with subsequent measurements taken against the same center coordinates of the Tycho Crater, where these coordinates are now expressed in the CR3BP rotating frame. For successful conic-based batch filter initialization and long-term CR3BP EKF convergence, it was found that the cadence for all optical measurements should be taken at 10 minutes for a simulated measurement noise of 0.1° one sigma uncertainty about the line-of-sight measurement unit vector. [ABSTRACT FROM AUTHOR]

Herein, nickel ferrite-based photocatalysts with enhanced light utilizing electrical charge transport properties have been reported for environmental remediation applications. The cobalt and holmium co-doped nickel ferrite [Ni1−x(Co)xFe2−y(Ho)yO4] nanoparticles and bare nickel ferrite (NiFe2O4) nanoparticles have been prepared via surfactant-supported wet-chemical techniques. The as-prepared ferritic photocatalyst's structural, morphological, and light harvesting features have been examined in detail using well-known physical, electronic, and optical methods. The co-doped ferrite photocatalyst's tuned structural features enable it to absorb maximum wavelengths from the U.V. and visible regions. This is because the co-doped Ni1−x(Co)xFe2−y(Ho)yO4 optical band gap is 1.73 eV; hence, the wavelength from the visible part possesses sufficient energies to trigger the electronic excitation in co-doped ferrite photocatalysts. Moreover, the co-doping-induced structural defects in the ferrite photocatalyst. These defects act as a reservoir for the charge species, mainly electrons, so the process of charge recombination is almost hampered for the Ni1−x(Co)xFe2−y(Ho)yO4 photocatalyst. In application terms, the photomineralization capabilities of doped and bare ferrite photocatalysts have been explored using crystal violet (CV) dye. The comparative photocatalytic evaluation of both nickel ferrite-based photocatalysts shows that co-doped ferrite degraded 96.02 % of CV dye. In comparison, the undoped one only degraded 64.84 % after 80 min of W-lamp light exposure. The results demonstrated that the Ho and Co co-doped ferrite photocatalyst exhibits excellent photocatalytic activity, suggesting its potential for environmental remediation applications in textile industrial discharges. [ABSTRACT FROM AUTHOR]

Polyvinyl alcohol (PVA) films impregnated with CdSe nanoparticles were evaluated for the effect of morphology (from spherical to rod-shaped) and concentration of CdSe, on the optical and mechanical properties. CdSe nanodots and nanorods were synthesized by a modified microemulsion method with hydrazine hydrate as the shape modulator. CdSe nanoparticles and PVA/CdSe films were characterized by high resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV–Vis spectroscopy and universal testing machine (UTM) analysis. The tensile strength and % elongation (at break) of PVA/CdSe films, increased from 32.8 MPa and 178 % (for CdSe nanorods) to 40.3 MPa and 259 % (for CdSe nanodots), respectively. The effect of loading of CdSe in PVA films, were evaluated at 0.1, 0.5, 1.0, 5.0 and 10 wt%. The tensile strength increased from 18.9 MPa (plain PVA) to 35.08 MPa (1 % CdSe) and increased upto 40 MPa for 10 % CdSe. The absorbance of PVA/CdSe films increased, while the reflectance and the transmittance decreased, with increasing wt% of CdSe in PVA films. The colour, density and water-vapour permeability of PVA/CdSe films, were also estimated. The biodegradability of PVA/CdSe films in soil was found to increase by 55 % as compared with PVA films. [ABSTRACT FROM AUTHOR]

GeO2-doped magnesium-telluroborate transparent glasses were synthesized in the current investigation using the traditional melt-quench procedure. XRD and FT-IR were used to examine the glasses' structural properties. Following the measurement of the density, various physical parameters (including oxygen molar volume, oxygen packing density, etc.) were estimated and examined. From the FTIR results, one can deduce that clear structural alterations are seen which support the presence and conversion of BO3 and BO4 units. This is a result of the glass network forming more GeO4, TeO4, and BO4 units, which means that decreased NBO is forming, and more stiff networks are forming as a result. The increase in the overall stretching force constant of the glasses may also have an impact on the elastic moduli. The optical parameters were studied as optical energy band gap, Urbach energy and refractive index of the fabricated glass. According to the HVL data, the current glasses have a significant ability to lessen the intensity of gamma rays with lower energy. The glass with a small amount of GeO2 has a high HVL, whereas the glass with a higher amount of GeO2 has a lower HVL, as shown by the HVL data. The G5 glass demonstrated its superiority as a shielding glass over the other glass samples (G1–G4). [ABSTRACT FROM AUTHOR]

Synaptic disturbances in excitatory to inhibitory (E/I) balance in forebrain circuits are thought to contribute to the progression of Alzheimer's disease (AD) and dementia, although direct evidence for such imbalance in humans is lacking. We assessed anatomical and electrophysiological synaptic E/I ratios in post-mortem parietal cortex samples from middle-aged individuals with AD (early-onset) or Down syndrome (DS) by fluorescence deconvolution tomography and microtransplantation of synaptic membranes. Both approaches revealed significantly elevated E/I ratios for AD, but not DS, versus controls. Gene expression studies in an independent AD cohort also demonstrated elevated E/I ratios in individuals with AD as compared to controls. These findings provide evidence of a marked pro-excitatory perturbation of synaptic E/I balance in AD parietal cortex, a region within the default mode network that is overly active in the disorder, and support the hypothesis that E/I imbalances disrupt cognition-related shifts in cortical activity which contribute to the intellectual decline in AD.

Quinolone antibiotic residues present a high risk for food safety and have gained widespread attention. Nanomaterials based sensors have the advantages of on-site application, sensitivity, and small sample volume requirement and has attracted significant interest in on-site detection technology research for quinolone antibiotics. This paper introduces the application of optical sensors including fluorescence, colorimetry, SERS, ICA and electrochemical sensors based on diverse nanomaterials in quinolone antibiotics detection and summarizes the characteristics of diverse sensors. The application of nanomaterials including quantum dots and upconversion in optical sensors, as well as those of carbon and metal nanomaterials and redox media in electrochemical sensors are reviewed and evaluated. The objective of this work is to provide new concepts for antibiotics detection in food and the development of sensors.

This paper demonstrates the synthesis of NixCd1-xS (x=0.8,0.6,0.4,0.2) nanoparticles by microwave-assisted chemical precipitation method. The prepared samples were characterized by XRD, EDAX, SEM, UV-VIS, and PL spectroscopy. The energy-dispersive x-ray analysis confirms the existence of Nickel, Cadmium and Sulphur in proper ratios. The DC electrical resistances were measured in the temperature range of 300 K-500 K. The temperature resistance curves of all the samples show phase transitions above a particular temperature. The UV and PL spectra of all the samples were compared and studied.

This work employed pulsed laser ablation to produce cellulose acetate butyrate-gold (CAB-Au) nanocomposite films and the evaluation of their structural and thermal characteristics using Raman, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Differential Scanning Calorimetry (DSC). In the frequency range 0.1–10 MHz, nanocomposite films' dielectric constant, loss, and electric modulus behavior were investigated as a function of temperature. The refractive index, finesse coefficient, Brewster coefficient, critical angles, dielectric function, and color properties of nanocomposite films were examined in the wavelength range 190–800 nm. X-ray diffraction shows a strong Au diffraction signal in all samples, confirming Au NPs. The SEM micrograph shows Au embedded in CAB. The CAB-Au nanocomposites had higher thermal stabilities (Tm) than pure CAB, and the DSC thermograms showed a fluctuating glass transition temperature due to the dynamics of organic-inorganic interactions in the nanocomposite films. Dielectric dispersion is caused by hidden dipolar polarization. The CAB (5 min) sample had the highest ac conductivity as a function of frequency at various temperatures as the Au content in the Au/CAB composite rose. The simplest quantum mechanical tunneling (QMT) model also best explains the ac conduction property. We found a relationship between the nanocomposites' refractive index and the amount (extent of incorporation) of Au in the materials, with laser irradiation time determining the various color constants. Tauc plots reveal a permitted transition with an optical energy gap of 5.1eV for the polymer film and 4.75eV after 10 and 20 min of laser irradiation.

Photothermolysis is the process that converts radiation energy into thermal energy, which results in the destruction of surrounding tissues or cells through thermal diffusion. Laser therapy that is based on photothermolysis has been a widely used treatment for various skin diseases such as skin cancers and port-wine stains. It offers several benefits such as non-invasiveness and selective treatment. However, the use of light, e.g., laser, for safe and effective photothermolysis becomes challenging due to the limited penetration of light into skin tissue as well as the presence of melanin, which absorbs this light. To solve the current issues, we propose an optical microneedle–lens array (OMLA) coated with gold in this work to directly deliver light to targeted skin layers without being absorbed by surrounding tissues as well as melanin, which results in the improvement of the efficiency of photothermal therapy. We developed a novel fabrication method, frame-guided micromolding, to prepare the OMLA by assembling two negative molds with simultaneous alignment. In addition, evaluations of the optical and heat transfer characteristics of the OMLA were performed. We expect our developed OMLA to play a crucial role in realizing more effective laser therapy by allowing the precise delivery of photons to the target area.

Microbial foodborne pathogens present significant challenges to public health and the food industry, requiring rapid and accurate detection methods to prevent infections and ensure food safety. Conventional single biosensing techniques often exhibit limitations in terms of sensitivity, specificity, and rapidity. In response, there has been a growing interest in multimodal biosensing approaches that combine multiple sensing techniques to enhance the efficacy, accuracy, and precision in detecting these pathogens. This review investigates the current state of multimodal biosensing technologies and their potential applications within the food industry. Various multimodal biosensing platforms, such as opto-electrochemical, optical nanomaterial, multiple nanomaterial-based systems, hybrid biosensing microfluidics, and microfabrication techniques are discussed. The review provides an in-depth analysis of the advantages, challenges, and future prospects of multimodal biosensing for foodborne pathogens, emphasizing its transformative potential for food safety and public health. This comprehensive analysis aims to contribute to the development of innovative strategies for combating foodborne infections and ensuring the reliability of the global food supply chain.

Acrylamide (AA), an odorless and colorless organic small-molecule compound found generally in thermally processed foods, possesses potential carcinogenic, neurotoxic, reproductive, and developmental toxicity. Compared with conventional methods for AA detection, bio/chemical sensors have attracted much interest in recent years owing to their reliability, sensitivity, selectivity, convenience, and low cost. This paper provides a comprehensive review of bio/chemical sensors utilized for the detection of AA over the past decade. Specifically, the content is concluded and systematically organized from the perspective of the sensing mechanism, state of selectivity, linear range, detection limits, and robustness. Subsequently, an analysis of the strengths and limitations of diverse analytical technologies ensues, contributing to a thorough discussion about the potential developments in point-of-care (POC) for AA detection in thermally processed foods at the conclusion of this review.

The structural, wettability, and optical characteristics of aluminum-doped zinc oxide (AZO) thin films were studied with the objective of understanding the impact of deposition power and deposition temperature. Thin films were deposited using a radio frequency (RF) magnetron sputtering technique. The power output of the RF was augmented from 200 to 260 W, and the temperature was increased from 50 to 200 °C, which led to the development of a (002) peak for zinc oxide. The study of film thickness was carried out using the Swanepoel envelope method from data obtained through the UV-Vis spectrum. An increase in surface roughness value was shown to be connected with fluctuations in temperature as well as increases in deposition power. The findings revealed that as deposition power and temperature increased, the value of optical transmittance decreased, ranging from 70% to 90% based on the deposition parameters within the range of wavelengths that extend from 300 to 800 nm. The wettability properties of the samples were studied, and the maximum contact angle achieved was 110°. A Peltier apparatus was utilised in order to investigate the anti-icing capabilities, which revealed that the icing process was slowed down 3.38-fold. This work extends the understanding of the hydrophobicity and anti-icing capabilities of AZO thin films, specifically increasing both attributes which provide feasible options for purposes requiring resistance to ice.

Diamond-like carbon (DLC) has attracted much attention due to its unique properties such as high chemical inertness, optical transparency, and high biocompatibility. In this study, the total gas flow rate was kept constant, while the ratio of reactive gases was varied to deposit nitrogen-doped diamond-like carbon thin films on glass substrates using radiofrequency plasma-enhanced chemical vapor deposition. The effects of the gas flow ratio on the composition, microstructure, surface morphology, and optical properties of the thin films were investigated through extended deposition times. It was found that with an increase in the nitrogen-to-methane gas flow ratio, the film surface became smoother and more compact. The maximum transmittance in the visible range reached 90%, and the highest and lowest transmittance in the same ultraviolet wavelength region differed by up to 25.62% among several sample groups. The optical bandgap decreased from 3.58 eV to 3.46 eV, contrary to the trend of the sp2 fraction variation. Compared with other studies, this study considered the preparation of nitrogen-doped diamondoids using a chemical vapor deposition method with a lesser total gas flow rate passed into it, which provides practical data reference value for the preparation of N-DLC.

Inspection of the technical condition of load-bearing structural elements of buildings and structures in the process of their construction and operation is an important issue at the present time. A fiber-optic monitoring system is proposed as a solution to the problem of early diagnosis of defects and damage to load-bearing building structures. A scheme has been developed for testing fiber-optic sensors, which make it possible to control the stress-strain state of monolithic reinforced concrete structures. For testing, a series of monolithic concrete beams of rectangular cross section has been made reinforced with fiber optics during their manufacturing. The values of mechanical stresses and deformations arising in beams under loading have been determined. Using the tested samples as an example, it has been established that the proposed fiber-optic monitoring system (FOMS) makes it possible to control stresses and deformations (and to predict the appearance and growth of cracks) in various building structures. The main element of the system is a hardware-software complex capable of estimating the parameters of a light wave at the output of the optical fiber. The distance from the installation site of the data processing unit to the measurement point can cover the area of 30 km. At this, fiber-optic sensors operate without additional power supply from a laser with the power of up to 30 mW. The proposed monitoring system has a low cost of one measurement point, it is easy to install, which is a good alternative to the electronic beacon-recorder device and the development of optical digital technologies in construction.

In this study, density functional theory (DFT) simulations have been used to study the structural, electrical and optical properties of AlAuO2 and AlAu094Fe006O2. Initially, the estimated bandgap of AlAuO2 0.45, 0.486, 0.419 and 2.49 eV in Perdew-Burke-Ernzerhof (PBE), Revised Perdew-Burke-Ernzerhof (RPBE), PBE for solids (PBE sol) and Becke three-parameter Lee-Yang-Parr (B3LYP) method respectively while AlAu094Fe006O2 has a zero-band gap after 6 % Fe doping. Then, density of state (DOS) and partial density of state (PDOS) were studied to determine the characteristics of the various orbitals of AlAuO2. The bonding characteristics and thermal stability of this crystal are determined by the Mulliken population charge and thermos physical parameters. Band edge of AlAuO2 was calculated which revealed that the AlAuO2 has suitable oxidation and reduction potential to degrade the contamination. A remarkable absorption has recorded for both AlAuO2 and AlAu094Fe006O2 in visible and ultraviolet region and capability to utilize photocatalytic dye degradation and hydrogen production through water splitting.

Background: Visual impairment in children negatively impacts their learning ability compared with their normally sighted peers and the use of optical devices may in turn assist the learner in their educational pursuit. Aim: To determine the reading rate of children with low vision, with and without the use of optical devices. Setting: The study was conducted at an eye clinic in KwaZulu-Natal. Method: A pilot study was conducted on 15 children with low vision, aged between 6 years and 19 years (mean = 13.86 ± 3.34 years). Reading rate was assessed at near, using the English Paediatric Rate of Reading Test, and evaluated with and without the use of optical devices. Results: The mean reading rates were 59.32 word per minute (wpm) ± 24.08 wpm and 67.04 wpm ± 25.63 wpm without and with the optical device, respectively (p = 0.087). Conclusion: While this was a pilot study having implications on statistical significance, the results indicated an improvement in reading rate with optical devices compared with without. Contribution: Vision is integral for the efficient performance of daily tasks. Improved reading performance relates to a happier child despite their visual limitations, hence managing low vision effectively impacts scholarly progression as well as quality of life including physical, mental and social well-being of the child.

Low-temperature synthesis of diamond has broader application prospects compared to traditional diamond synthesis, but it faces issues such as low deposition rate and poor diamond quality. In this study, CH4–CO–H2 were used as reaction gases, and a pulsed discharge MPCVD apparatus was used to deposit diamond films at a substrate temperature of 400 °C and different frequencies were investigated. The results showed that the deposition rate of the pulse discharge was faster than that of continuous microwave discharge. The fastest deposition rate was observed at 500Hz, and crystal size became finer with increasing frequency, while the crystal orientation changed from (100) to (111). A diamond peak at 1333 cm−1 was observed in the Raman spectrum, and the diamond grain size was found to be biggest at 750Hz based on the measured half-width of the peak. Plasma OES analysis revealed that the brightness of CO increased gradually with increasing frequency, while the brightness of H showed an initial increase followed by a decrease. Comparison of emission spectra during low-temperature deposition with a single carbon source showed that CO participated in the reaction for low-temperature diamond synthesis.

Zinc oxide semiconductors have received significant research attention over the past decade owing to their diverse applications. In this paper, we report the development and characterisation of ZnO thin films prepared by radio-frequency (RF) magnetron sputtering. The optical, anti-icing, wettability, and structural properties of the films were investigated at various sputtering power levels and temperatures. With an increase in the power from 175 to 250 W, the ZnO thin films showed fine (002) structures. X-ray diffraction analysis of the coated thin films revealed a considerable increase in the (002) peak intensity along the c-axis with increasing power and temperature. Increasing the sputtering power from 175 to 250 W and the deposition temperature from 150 to 300 °C led to an increase in the average size of the grains from 10.548 to 13.151 nm and from 9.97 to 13.151 nm, respectively. The water contact angle possibly depends on the RF power and temperature employed for material deposition. Within the 350–800 nm range, the prepared films achieved optical transmissions of 92%–88%, refractive indices of 1.52–1.50, and band gaps of 3.28–3.24 eV. The anti-icing properties were also improved by adjusting the sputtering power and temperature during material deposition. [ABSTRACT FROM AUTHOR]

Synthesis of tellurite borate (35-x) TeO2 + 35 B2O3 + 20 Bi2O3 + 10 Li2O + x CeO2 and x = 0, 0.5, 1.5, 3 mol% glasses have been achieved by using the melt quenching technique. Density, X-ray diffraction (XRD), Raman spectroscopy measurements and UV–Vis analysis were measured. Dielectric measurements were recorded in the frequency range of 100 Hz–100 kHz at room temperature. XRD patterns of all the investigated glass samples doped with CeO2 are completely amorphous. Densities of the prepared glasses increased from 4.80 to 4.89 g/cm3 and molar volumes decreased from 36.74 to 36.14 cm3/mole. Raman spectroscopy reveals that the Raman intensity increases with increasing substitution of CeO2 by TeO2. UV–Vis analysis reveals that a higher CeO2 substitution ratio increased the absorbance and optical properties of produced glass samples. The CeO2 content of tellurium borate glass samples were found to affect all of the optical characteristics. With increasing CeO2 concentration, the optical energy gap decreases (E g opt ) from 2.77 to 1.96 eV for direct allowed transitions and from 2.45 to 1.82 eV for indirect allowed transitions. It has also been studied how electrical conductivity and dielectric properties change with frequency and composition. Values ε′, ε″ and σac of sample with x = 0 are greater than those values of with x = 3. The variation of the imaginary part of the electric modulus (M″) versus frequency (F) plot curve is asymmetric of non-Lorentzian type. A shift of the frequency peak towards the higher frequency region was observed by increasing CeO2 mol%. [ABSTRACT FROM AUTHOR]

CS/PVP blend embedded by Sr-hexaferrite nanoparticles as a novel composite material to improve the optical and magnetic properties of composite samples. This work aimed to study and compare the functional and physical properties of CS/PVP film after and before adding SrFe12O19 with different weight percentages to form nanocomposite film with chemical formula CS/PVP/x Wt% SrFe12O19; x = 1, 3, 5 and 7. SrFe12O19 was prepared successfully by using citrate auto-combustion methods, then added to CS/PVP blend with different weight percentages. XRD shows the formation of Sr-hexaferrite in a single phase with an average crystallite size 44 nm. The semi-crystalline nature of CS/PVP film decreases with the addition of Sr-hexaferrite. FTIR displays the interaction between CS/PVP and SrFe12O19 by changing the intensity and broadening the OH band. HRTEM images show that SrFe12O19 has a rod structure and has average particle size ranging from 50 to 100 nm. The coercivity value increased by increasing the weight% of nanofiller as it increased from 421 Oe for SrFe12O19 to 4502.6 and 4488.2 Oe for x = 3 wt% and 7 wt% for SrFe12O19. The transition between the top of the valance band and the bottom of the conduction band in CS/PVP/ x Wt % SrFe12O19; x = 1, 3, 5, 7 system occurred through the indirect transition. [ABSTRACT FROM AUTHOR]

The application of surface coatings is a popular technique to improve the performance of materials used for medical and dental implants. Ternary silicon carbon nitride (SiCN), obtained by introducing nitrogen into SiC, has attracted significant interest due to its potential advantages. This study investigated the properties of SiCN films deposited via PECVD for dental implant coatings. Chemical composition, optical, and tribological properties were analyzed by adjusting the gas flow rates of NH3, CH4, and SiH4. The results indicated that an increase in the NH3 flow rate led to higher deposition rates, scaling from 5.7 nm/min at an NH3 flow rate of 2 sccm to 7 nm/min at an NH3 flow rate of 8 sccm. Concurrently, the formation of N-Si bonds was observed. The films with a higher nitrogen content exhibited lower refractive indices, diminishing from 2.5 to 2.3 as the NH3 flow rate increased from 2 sccm to 8 sccm. The contact angle of SiCN films had minimal differences, while the corrosion rate was dependent on the pH of the environment. These findings contribute to a better understanding of the properties and potential applications of SiCN films for use in dental implants. [ABSTRACT FROM AUTHOR]

The bandgap energy and density of the sample were found by the analytical method. The density was found to increase up to 5 mol%, depicting the compactness of the sample and then decreasing with gadolinium content. Molar volume (Vm), Gd3+ ion concentration (N), refractive index (n), electronic polarizability (αe), reflection loss (RL), polaron radius (rp), internuclear distance (ri), field strength(F), dielectric constant(ɛ) of the sample were calculated. [ABSTRACT FROM AUTHOR]

We previously documented geographic distributions of the optically brightest lightning on Earth—known as "superbolts"—using two space‐based instruments: the photodiode detector (PDD) on the Fast On‐orbit Recording of Transient Events (FORTE) satellite and the Geostationary Lightning Mapper (GLM) on NOAA's Geostationary Operational Environmental Satellites. In this study, we further examine the superbolts identified by the PDD and GLM to reconcile the differences between their geographic distributions. We find that both the physical extent of the parent flash and the development speed of its leaders are important for making a superbolt. The oceanic PDD superbolts tend to occur early in flashes that rapidly expand laterally into long horizontal "megaflashes." The top GLM superbolts occur over land at later times in particularly large megaflashes. These land‐based flashes grow more slowly until they extend over multiple hundreds of kilometers. The FORTE PDD missed these delayed superbolts due to limitations in its triggering. Coincident Tropical Rainfall Measuring Mission measurements show that the warm season megaflash superbolts detected by Lightning Imaging Sensor/GLM and wintertime oceanic superbolts observed by the PDD occur in otherwise similar thunderstorm environments. Both are marked by: low storm heights (<10 km), widespread precipitation near the surface, small infrared brightness temperature gradients, and low flash rates. We suggest that the vertically compact, stratiform nature of these clouds provides favorable conditions for superbolt production. Plain Language Summary: The brightest optical pulses from lightning seen from space have been termed "superbolts." Superbolts are incredibly rare and represent flashes of light that are at least 100 times brighter than what we typically see from lightning. Curiously, the locations and times associated with these brightest optical pulses differ based on the instrument and satellite used. Previous assessments with the photodiode detector (PDD) on the Fast On‐orbit Recording of Transient Events (FORTE) satellite identify wintertime lightning around Japan, along the Gulf Stream in the Atlantic Ocean, and in the Mediterranean Sea as frequent sources of superbolts. However, assessments with NOAA's Geostationary Lightning Mapper (GLM) find hotspots in regions with large‐horizontal "megaflashes"—particularly, the La Plata basin in south America and the south‐central United States in North America. In this study, we examine how these differences in optical superbolt detections arise. We find that the differing global distributions can be explained by the FORTE PDD missing superbolts that occur late in the flash due to its trigger count limit—an issue not encountered by GLM. Key Points: The top Fast On‐orbit Recording of Transient Events (FORTE) photodiode detector, Lightning Imaging Sensor (LIS), and Geostationary Lightning Mapper (GLM) detections capture different portions of the population of the top optical lightning eventsThese differences arise from nuances in the design and operation of these sensors that introduce detection biasesThe FORTE superbolt distribution only represents a subset of all superbolts, which should also include the top LIS/GLM events [ABSTRACT FROM AUTHOR]

[Display omitted] Aboveground biomass (AGB) is an essential factor in rice ecological research. Optical variables (e.g. reflectivity and vegetation index (VI)) are widely adopted in monitoring AGB while spatial information (e.g. texture) is less introduced into research. Limited research is available regarding the impact on the monitoring accuracy caused by the utility of VI and texture in AGB estimation at different combinations of growth stages. To compare the improvements caused by the involvement of texture at different combinations of growth stages, a hyperspectral camera was mounted on an unmanned aerial vehicle (UAV) to obtain images of rice field during the early growth stages (including the tillering, jointing and booting stage) under five nitrogen levels over two years. Spectral and spatial information derived from images was utilized to compute VIs and textures at different combinations of growth stages. After analyzing their correlations with AGB, multiple stepwise regression (MSR) and multiple linear regression (MLR) techniques were employed to establish rice AGB models using vegetation index (VI), vegetation index combined with the corresponding-band texture (VI-CBT) and vegetation index combined with the full-band texture (VI-FBT). It was found that the models using VI and texture enhanced the capability of the conventional VI to estimate AGB at different combinations of growth stages. The combination of VI and FBT achieved the most accurate estimation, followed by the VI-CBT. Different combinations of growth stages had diverse responses to textures. Overall, the tillering stage had the maximum response to the involvement of textures, followed by the booting stage. Models using VI-CBT and VI-FBT significantly improved the AGB estimation at the booting and tillering stage, respectively. The monitoring accuracy of the jointing stage showed a slight response to the involvement of texture. At the multiple growth stages, the monitoring effect of the tillering-booting stages was significantly improved, followed by the jointing-booting stages either using the model based on VI-CBT or VI-FBT. Models using VI and texture tended to yield larger improvements on the error values at the extreme AGB levels. Near-infrared and red-edge bands were the sensitive bands to estimate rice AGB, and MEA, COR were favorable textures to monitor the AGB. This study quantified the model improvements of using VI and texture in rice AGB estimation at different combinations of growth stages, delivering guidance for timely and accurate rice management in the field. [ABSTRACT FROM AUTHOR]

The bandgap value of the thin films of Pb1-xCdxS could be tailored between 3.7 and 2.59 eV by adjusting the value of doping parameter 0.0 ≤ x ≤ 1.0. Ultra-thin films of average thickness 115 nm were deposited on glass substrates using the spin coating method. The structure and microstructure properties of the obtained thin films were studied using Rietveld analysis of x-ray diffraction patterns with a grazing incidence setup. Scanning electron microscopy was used to investigate the film's surface morphology and thickness. Photoluminescence spectra were conducted to explore the various emitted colors correlated with defect states formed in the lattice of the obtained films. The effect of Cd content on the optical absorbance, reflectance, refractive index, extinction coefficient. Dielectric constant, loss functions, optical conductivity and nonlinear optical parameters of the films were investigated in detail. The film with Cd content x = 0.4 had superior properties among other films. All films displayed a normal and/or anomalous dispersions of n values depending on the wavelength range. Several linear and nonlinear optical and photonic applications have been proposed due to the films' improved nonlinear optical values. [ABSTRACT FROM AUTHOR]

This study investigates the optimization of nickel-infused alumina nanostructure for enhanced solar-thermal energy conversion. The optimization is based on the analytical model using the transfer matrix method, which is first validated with experimental results and then compared with a finite element model. The optimal nanostructure of the solar absorber shows a high solar absorptance of 0.87 and a low thermal emittance of 0.08. The optimal design can achieve a total net heat flux of 815 W/m2, approximately 26% higher than the nominal value of 647 W/m2 corresponding to the baseline design. [ABSTRACT FROM AUTHOR]

In this study, we investigate how changing the nitrogen flow rate, the length of time during deposition, and the intensity of pressure have an impact on the resulting chromium oxynitride coatings. Depending on the sputtering conditions, the X-ray diffraction analyses reveal different textures in the Cr2O3 and Cr2N phases. Films deposited with varying nitrogen flow rates and deposition durations experience compressive strains, whereas films produced with varying sputtering pressures witness tensile stresses. Film surface energies and contact angles were measured with a contact angle goniometer. Because of their hydrophobic properties, chromium oxynitride coatings may find use as water-repellent, self-cleaning surfaces. Chromium oxynitride films' absorption and transmission curves were recorded using a UV-Vis-NIR spectrophotometer. The band gap of chromium oxynitride coatings reduces with a rise in the flow of nitrogen and sputtering time but widens with increasing deposition pressure. [ABSTRACT FROM AUTHOR]

Accurate and reliable mapping of fire extent and severity is critical for assessing the impact of fire on vegetation and informing post-fire recovery trajectories. Classification approaches that combine pixel-wise and neighbourhood statistics including image texture derived from high-resolution satellite data may improve on current methods of fire severity mapping. Texture is an innate property of all land cover surfaces that is known to vary between fire severity classes, becoming increasingly more homogenous as fire severity increases. In this study, we compared candidate backscatter and reflectance indices derived from Sentinel 1 and Sentinel 2, respectively, together with grey-level-co-occurrence-matrix (GLCM)-derived texture indices using a random forest supervised classification framework. Cross-validation (for which the target fire was excluded in training) and target-trained (for which the target fire was included in training) models were compared to evaluate performance between the models with and without texture indices. The results indicated that the addition of texture indices increased the classification accuracies of severity for both sensor types, with the greatest improvements in the high severity class (23.3%) for the Sentinel 1 and the moderate severity class (17.4%) for the Sentinel 2 target-trained models. The target-trained models consistently outperformed the cross-validation models, especially with regard to Sentinel 1, emphasising the importance of local training data in capturing post-fire variation in different forest types and severity classes. The Sentinel 2 models more accurately estimated fire extent and were improved with the addition of texture indices (3.2%). Optical sensor data yielded better results than C-band synthetic aperture radar (SAR) data with respect to distinguishing fire severity and extent. Successful detection using C-band data was linked to significant structural change in the canopy (i.e., partial-complete canopy consumption) and is more successful over sparse, low-biomass forest. Future research will investigate the sensitivity of longer-wavelength (L-band) SAR regarding fire severity estimation and the potential for an integrated fire-mapping system that incorporates both active and passive remote sensing to detect and monitor changes in vegetation cover and structure. [ABSTRACT FROM AUTHOR]

In this study, we explore the effects of Zn doping on the electronic, optical, and thermoelectric properties of α-SnSe in bulk and monolayer forms, employing density functional theory calculations. By varying the doping concentrations, we aim to understand the characteristics of Zn-doped SnSe in both systems. Our analysis of the electronic band structure using (PBE), (SCAN), and (HSE06) functionals reveals that all doped systems exhibit semiconductor-like behavior, making them suitable for applications in optoelectronics and photovoltaics. Notably, the conduction bands in SnSe monolayers undergo changes depending on the Zn concentration. Furthermore, the optical analysis indicates a decrease in the dielectric constant when transitioning from bulk to monolayer forms, which is advantageous for capacitor production. Moreover, heavily doped SnSe monolayers hold promise for deep ultraviolet applications. Examining the thermoelectric transport properties, we observe that Zn doping enhances the electrical conductivity in bulk SnSe at temperatures below 500 K. However, the electronic thermal conductivity of monolayer samples is lower compared to bulk samples, and it decreases consistently with increasing Zn concentrations. Additionally, the Zn-doped 2D samples exhibit high Seebeck coefficients across most of the temperature ranges investigated. [ABSTRACT FROM AUTHOR]

Electroanalytical and optical techniques are widely used in the development of nanomaterials-based sensor platforms. These techniques have a quick response, high sensitivity, and selectivity. Electroanalytical and optical techniques are widely used in the development of nanomaterial-based sensor platforms. These sensors must be able to detect biomarkers, pathogens, toxins, and pharmaceuticals in biological matrices associated with cardiovascular disease, cancer, and neurodegenerative diseases. Considering these pathophysiologies, numerous investigations have been undertaken to develop sensors for early diagnosis and treatment, utilizing nanomaterials such as quantum dots. Graphene quantum dots (GQDs), which are ideally nanometer-sized graphene fragments, have recently received increased attention due to their excellent physicochemical properties such as fast electron mobility, photostability, water solubility, biocompatibility, high specific surface area, and nontoxicity. Apart from the properties mentioned above, GQDs provide π–π interactions, electrostatic, and covalent interactions with an analyte, and ease of synthesis as well as the ability to combine with other nanomaterials, which have enabled their use in various sensing platforms. This review summarizes recent advances in GQDs-based nanocomposites for sensor applications, with a focus on electroanalytical and optical techniques, as well as current challenges and future prospects. [ABSTRACT FROM AUTHOR]

The upgrading of useful biosensors having advantages in disease monitoring besides detection has been sped up by the demand for quick, cheap, portable, easy screening procedures. Bioanalytical devices such as Biosensors have a number of distinguishing benefits over conventional analytical techniques, including high accuracy and specificity, ease of handling, economic friendly, and the potential for downsizing and mass production. With an emphasis on electrochemical and optical sensors, this study examines current developments in the design, performance, and applications of biosensors. Due to its advantages of high sensitivity, specificity, and rapid analysis, electrochemical sensors have demonstrated a wide range of applications in biological detection whereas the optical biosensors covered in this article have enabled diagnosis of SARS-CoV-2, which highlighted the importance of creating swift and extremely sensitive diagnostic methods for quickly identifying infected patients using LSPR, SERS, FET, EC biosensors. [ABSTRACT FROM AUTHOR]

Lanthanides (Ce, Pr, Nd and Gd) 1, 3, 5 and 10 wt% of each were loaded into a pristine sodium aluminium phosphate glass matrix in order to simulate the immobilization of minor actinides (Am, Np, Cm) produced from spent nuclear fuel reprocessing. The optical parameters pertaining to these glasses were derived from the diffuse reflectance spectra. The systematic dependence of the physical and structural properties of these glasses on the dopants and the concentration of the latter was studied by XRD and Raman spectroscopy. The results on Rare Earth (RE) doped sodium aluminium phosphate are being reported for the first time. The physical parameters such as density, molar volume and oxygen packing density were evaluated. The XRD patterns showed the absence of any crystalline phase in these glasses. The relative % areas of (PO3)−2(Q2) bonds increase, whereas Q0 and Q1 tend to decrease with the addition of lanthanide oxides as compared to the pristine glass. The addition of different lanthanide oxides was found to depolymerize the network by forming more Q2 short chains. The results showed that the band gap energy (Eg) depends strongly on the cation field strength (CFS) of the lanthanides. The band gap energy decreases with an increase in the lanthanide concentration in the glass matrix. Praseodymium-doped glasses showed the highest Eg values (5.28–5.23 eV). The photoluminescence spectra confirm the characteristic excitation and emission peaks for the cations Ce+3, Pr+3 and Gd+3 and their variation with concentration was analysed. [ABSTRACT FROM AUTHOR]

Nano-crystalline CdTe films were coated on a glass substrate by vacuum evaporation (PVD) technique, with the annealed temperature at (25, 100, 150, and 200 °C). The samples were examined by Uv-visible instrument to investigate the transmittance and absorption. The dependency of the absorption coefficient (a) on the wavelength has been investigated. The X-ray diffraction revealed that cubic crystalline was obtained and the peak intensity increased as the temperature increased. The crystallite size increased during grans growth when annealed temperature increased. The estimated energy gaps of the CdTe films were 1.86, 1.87, 1.85, and 1.84 eV, due to the differences in particle sizes. Electrical characteristics have been made to detect the resistivity and conductivity and it was found that the resistivity changes directly with the increase of the energy gap and inversely with the increase in the conductivity of the CdTe films. The surface morphology was homogenous and very smooth surfaces were detected. [ABSTRACT FROM AUTHOR]