Decrease In Peak Intensity Research Articles

Chlorophyll films for radiation dosimetry: a feasibility study

Abstract Novel Chlorophyll-PVA composite films have been prepared and tested for the dosimetry of therapeutic radiation. The radiation response has been quantified using UV–vis spectroscopy. FTIR and XRD spectroscopies have been used to characterize the physical properties and irradiation response of the films. The films have shown response towards the therapeutic x-rays beams of 6 MV nominal energy in the tested dose range of 0.25 Gy to 32 Gy in discrete dose levels occurring in the geometric progression series of 2. The dosimeter has been found to exhibit sensitivity at a low dose of 0.25 Gy. The dose response curve of the dosimeter exhibits an exponential relationship of the absorbance and absorbed dose. A region of saturated absorbance has been observed beyond 4 Gy. The peak intensities of the FTIR spectra have been found to decrease with increasing doses as compared to the unirradiated samples, because of the changes in the bond polarities and molecular geometries. The XRD spectra indicates a change in the molecular orientation resulting in a decrease in peak intensity with increasing dose. This study indicates the feasibility of chl-PVA films in the dosimetry of therapeutic radiation. This film dosimeter can be processed locally with minimum resources and standardized against a known standard before clinical use. The chlorophyll molecules need careful handling owing to their sensitivity to light and temperature.

Spatio‐Temporal Variations and El Niño Modulation of Meteorological Droughts in Malaysia

ABSTRACTMeteorological droughts in Malaysia have significantly impacted critical sectors such as agriculture, water resources, health, the environment, tourism and various socio‐economic sectors, affecting the population's livelihood and well‐being. This study analyses drought characteristics over a 39‐year period, from 1982 to 2021, using the Standardised Precipitation Index (SPI) derived from 5‐km resolution Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS). The droughts were assessed on 3‐, 6‐, 9‐ and 12‐month timescales to investigate spatio‐temporal variations in characteristics such as frequency, duration, peak, severity and intensity. The study also provides an in‐depth analysis of large‐scale drought modulation, particularly associated with the El Niño phenomenon and its teleconnection in the Maritime Continent. Depending on the location and timescale, the number of meteorological drought occurrences varied from 10 to 22 for the 3‐month timescale and 4 to 14 for the 12‐month timescale. Generally, as the timescale of a drought increases, the peak intensity decreases, while the duration and severity increase. Additionally, drought intensity decreases over longer timescales. These characteristics show significant spatial variations. Results indicate that meteorological droughts in Malaysia were almost entirely modulated by the El Niño phenomenon through its induced teleconnection over the Maritime Continent. Drought characteristics exhibit a strong seasonality linked to changes in the Walker circulation and the strengthening and weakening of anticyclonic circulations associated with Rossby waves induced by heating in the Pacific Ocean. Very strong El Niño events had the most significant influence on the droughts. The positive Indian Ocean Dipole (pIOD) strengthened the effects of El Niño but it itself had no significant influence on the droughts. In most regions, there were no significant trends in the characteristics of meteorological droughts. However, in northeast Peninsular Malaysia and some scattered areas along the west coast of the peninsula, significant trends are observed in peak, duration and severity.

TEMPERATURE EFFECT ON THERMOLUMINESCENCE KINETIC PARAMETERS OF NANO-ALUMINA

This research explores the fundamental thermoluminescence characteristics of irradiated nano-α-alumina particles, investigating their response to varying heating rates. The study involves recording TL luminescence curves, revealing a distinct peak with a maximum at approximately 202°C. As dose levels increase, the peak consistently shifts towards lower temperatures, indicating adherence to non-first-order kinetics (b≠1). The crystallite size was calculated using XRD analysis and estimated as 40nm. To examine the impact of the heating rate on the TL glow curve and derive kinetic parameters for nano α-Al2O3, specimens were exposed to a 6 kGy dose. Subsequently, TL glow curves were documented over a temperature range from room temperature to 300°C, employing different heating rates (2, 4, 6, 8 and 12°C/s). The peak temperature of the glow peak shifts towards higher temperatures as the heating rate increases and the peak intensity continuously diminishes, aligning with TL theory. The observed decrease in TL glow peak intensity with escalating heating rates is attributed to thermal quenching, where quenching efficiency rises at higher temperatures. Normalizing maximum TL intensities to the lowest heating rate (2°C/s) reveals a substantial 22% decrease in peak intensity.

Alterations in Regional Brain Microcirculation in Patients with Sepsis: A Prospective Study Using Contrast-Enhanced Brain Ultrasound.

Alterations in regional brain microcirculation have not been well studied in patients with sepsis. Regional brain microcirculation can be studied using contrast-enhanced brain ultrasound (CEUS) with microbubble administration. CEUS was used to assess alterations in regional brain microcirculation on 3 consecutive days in 58 patients with sepsis and within 24h of intensive care unit admission in 10 aged-matched nonseptic postoperative patients. Time-intensity perfusion curve variables (time-to-peak and peak intensity) were measured in different regions of interest of the brain parenchyma. The mean arterial pressure, cardiac index (using transthoracic echocardiography), global cerebral blood flow (using echo-color Doppler of the carotid and vertebral arteries), mean flow velocities of the middle cerebral arteries, and brain autoregulation (using transcranial echo-color Doppler) were measured simultaneously. The presence of structural brain injury in patients with sepsis was confirmed on computed tomography imaging, and encephalopathy, including coma and delirium, was evaluated using the Glasgow Coma Scale and the Confusion Assessment Method in the Intensive Care Unit. Of the 58 patients with sepsis, 42 (72%) developed acute encephalopathy and 11 (19%) had some form of structural brain injury. Brain autoregulation was impaired in 23 (40%) of the patients with sepsis. Brain microcirculation alterations were observed in the left lentiform nucleus and left white matter of the temporoparietal region of the middle cerebral artery in the sepsis nonsurvivors but not in the survivors or postoperative patients. The alterations were characterized by prolonged time-to-peak (p < 0.01) and decreased peak intensity (p < 0.01) on the time-intensity perfusion curve. Prolonged time-to-peak but not decreased peak intensity was independently associated with worse outcome (p = 0.03) but not with the development of encephalopathy (p = 0.77). Alterations in regional brain microcirculation are present in critically ill patients with sepsis and are associated with poor outcome. Trial registration Registered retrospectively on December 19, 2019.

Biosynthesis of copper nanoclusters for fluorescence detection of bilirubin in biofluids.

Copper nanoclusters (Cu NCs) have shown significant attention in sensing of molecular and ionic species. In this work, a single-step biosynthetic approach was introduced for the preparation of fluorescent Cu NCs using Holarrhena pubescens (H.pubescens) leaves extract as a template. The synthesized H.pubescens-Cu NCs act as a nanomolecular probe for the detection of bilirubin in biofluids. The synthesized H.pubescens-Cu NCs displayed highest fluorescence intensity at 454 nm, when excited at 330 nm. Importantly, selective detection of bilirubin was obtained by introducing H.pubescens-Cu NCs as a simple molecular probe. The interaction of bilirubin and H.pubescens-Cu NCs resulted in a remarkable decrease in the emission peak intensity. The developed H.pubescens-Cu NCs-based bilirubin molecular probe has a wide linear range of 0.5-20.00 μM with the limit of detection of 30.54 nM for bilirubin. The promising application of H.pubescens-Cu NCs-based molecular probe was assessed by assaying bilirubin in spiked biofluids.

Unravelling Structural, Optical, and Band Alignment Properties of Mixed Pb-Sn Metal-Halide Quasi-2D Ruddlesden-Popper Perovskites.

Lead-tin (Pb-Sn) mixed-halide perovskites show potential for single-junction and tandem solar cells due to their adjustable band gaps, flexible composition, and superior environmental stability compared to three-dimensional (3D) perovskites. However, they have lower power conversion efficiencies. Understanding band alignment and charge carrier dynamics is essential for enhancing photovoltaic performance. In this view, herein we have prepared thin films of mixed Pb-Sn-based two dimensional (2D) Ruddlesden-Popper (RP) perovskites BA2FA(Pb1-xSnx)2I7 using a solution-based method. XRD study revealed the formation of orthorhombic phases for pristine (BA2FAPb2I7) and mixed Pb-Sn perovskite thin films. UV-vis analysis showed that different n = 2 and n = 3 phases are present in the pristine sample. In contrast, Pb-Sn-doped samples showed no signature of other phases with a prominent red-shift in the visible spectral region. Cyclic voltammetry showed peaks for electron transfers at the band edges. Additionally, electrochemical and optical band gap matching was observed, along with decreased peak intensity due to less reactant and altered electrolyte-perovskite interface stability. Density functional theory (DFT) calculations revealed that the reduced band gap is due to the alteration of electrostatic interactions and charge distribution within the lattice upon Sn substitution. Low-temperature PL analysis provided insights into charge carrier dynamics with Sn substitution and suggested the suppression of higher n phases and self-trapped excitons/carriers in mixed Pb-Sn quasi-2D RP perovskite thin films. This study sheds light on the electron transfer phenomena between TiO2 and SnO2 layers by estimating band offsets from valence band maximum (VBM) and conduction band minimum (CBM), which is crucial for future applications in fabricating stable and efficient 2D-Pb-Sn mixed perovskites for optoelectronic applications.

Synthesis and Characterization Studies of Pure and Co Doped ZnO Nano Thin Films

General Background: Thin-film technology is pivotal in advancing modern optoelectronic devices due to its ability to tailor material properties at the nanoscale. Specific Background: Zinc oxide (ZnO) and cobalt oxide (CoO) are prominent materials in this field, with doping techniques such as cobalt incorporation offering potential enhancements in film properties. Knowledge Gap: The impact of cobalt doping on the structural and optical properties of ZnO thin films remains inadequately explored, particularly concerning varying doping concentrations. Aims: Aims to elucidate the effects of cobalt doping on ZnO thin films' structural and optical characteristics, with concentrations of Zn0.6Co0.4O and Zn0.8Co0.2O compared to pure ZnO and CoO films. Results: Thin films were prepared via spin coating on glass substrates at 3000 rpm for 30 seconds. X-ray diffraction analysis revealed that pure ZnO films possess a hexagonal polycrystalline structure, whereas CoO films exhibit a cubic structure. Doping with cobalt resulted in a decrease in peak intensity at the (111) orientation and an increase in grain size. Optical measurements indicated enhanced transmittance and modified absorbance spectra with increased cobalt content, showing maximum absorbance at short wavelengths and diminished values in the visible region. Reflectivity increased with photon energy before decreasing at higher energies. Novelty: Cobalt doping significantly alters both structural and optical properties of ZnO films, with distinct changes in lattice constants, grain size, and optical behavior, suggesting a potential route for optimizing ZnO-based materials. Implications: Cobalt-doped ZnO films hold promise for improved performance in optoelectronic applications, such as solar cells and sensors, necessitating further research into diverse doping strategies to fully harness their technological potential. Highlights: Cobalt doping alters ZnO thin films' structural and optical properties. Spin coating method used at 3000 rpm for 30 seconds. Enhanced optical properties suitable for optoelectronic applications. Keywords: Thin films, Zinc oxide, Cobalt doping, Optical properties, X-ray diffraction

Investigation on the Potential of Some N-phenylalkanehydrazides as Superoxide Anion Radical Scavengers and Glutathione Peroxidase Binders with ADME Prediction: Comparison with Vitamin C

Objective: An investigation on the antioxidant activity and ADME properties of some N-phenylalkanehydrazides (NPhs) in comparison with ascorbic acid was carried out. Materials and Methods: The power of the compounds to scavenge the superoxide anion radical was examined using cyclic voltammetry. Furthermore, molecular docking was used to examine how NPhs bind to the antioxidant enzyme glutathione peroxidase (GPx). Finally, ADME properties were predicted using the SwissADME webserver. Results: The results showed that the studied compounds had significantly higher EC50 values than Vitamin C and displayed spontaneous binding with GPx with binding energy similar to ascorbic acid. Also, substantial values emerged from the predictive analysis of drug-likeness and bioavailability characteristics. Discussion: First, the EC50 of the compounds under study was determined by assessing the decrease in the anodic current peak intensity; this demonstrated significant radical scavenging activity. Next, the electrostatic way of binding with ROS radical and with antioxidant enzyme was disclosed by the binding free energies; however, the oxygen and nitrogen atoms in the compounds' structures might make many conventional hydrogen bonds with amino acids. Finally, NPh (a) followed all the rules for drug-likeness and bioavailability estimates, making it a promising moiety for synthesising new antioxidant chemicals. Conclusion: The current study is a hybrid of experimental and computational methods that complement each other perfectly.

Investigations of adsorption and photoluminescence properties of encapsulated Al–ZnO nanostructures: Synthesis, morphology and dye degradation studies

This study focuses on the solution combustion approach to examine the nanostructures of undoped and doped ZnO with different concentrations of Al (0.1 % and 0.2 %). Various physical techniques were utilized to characterize the synthesized nanoparticles. X-ray diffraction (XRD) revealed the crystalline materials, while scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) findings confirmed the products with particle size and the insertion of Al into the ZnO lattice. Fourier-transform infrared spectra (FTIR) confirmed the presence of different functional groups in the obtained material. The results indicate that Al-doped ZnO (Al–ZnO) nanoparticles show promising properties for optoelectronics and photoluminescence. Photoluminescence analysis indicated that an increase in Al3+ (0.2 %) concentration resulted in a decrease in peak intensity and an increase in the full width at half maximum. The band gap was calculated using the Taucs plot. The study also highlights the effectiveness of Zn1-xAlxO nanostructures in degrading organic pollutants, particularly in adsorbing Malachite Green (MG) dye. Among the samples, the 0.2 % Al-doped ZnO exhibited superior dye degradation efficiency due to its enhanced adsorption capacity and smaller particle size, as evidenced by multilayer adsorption capacity and chemisorption during the degradation process. This study provides valuable insights into the potential applications of Al-doped ZnO nanoparticles in various environmental and technological fields, emphasizing their significance in the degradation of organic pollutants.

High performance of straight and U-shaped probe microfiber sensors for sucrose solution detection applications

A low cost, highly sensitive sensor with easy fabrication has been successfully developed to detect variations in the concentration of sucrose solutions using a microfiber probe sensor. The microfiber probe was fabricated using a flame brushing mixture of butane and oxygen with single-mode optical fiber material and pulled on both sides to achieve a size of 16.48 µm. These microfiber probes were characterized into two sensor probe shapes: straight and u-shaped, to measure variations in the sucrose solution concentration. The results for both probe shapes showed a decrease in peak output intensity and a shift in peak wavelength as the sucrose concentration increased from 0.5% to 3%. The straight shape exhibited a sensitivity of 0.241 dBm/% with a slope linearity of 99.5% and a resolution of 0.0415%, while the U-shape had a sensitivity of 2.692 dBm/% with a slope linearity of 90.6% and a resolution of 0.0030%. The measurement spectra results indicated significant differences in u-shape at each concentration. In conclusion, both microfiber sensor probe shapes exhibited excellent performance and are suitable for use as chemical sensors to measure variations in solutions.

Looking into how nickel doping affects the structure, morphology, and optical properties of TiO2 nanofibers

In this paper, we have systematically studied the structural, morphological, and optical properties of Ni-doped TiO2, synthesized via a simple, cost-effective electrospinning method followed by calcination at 500 °C. The nanofibers with a core-shell structure were relatively homogeneous, smooth and randomly oriented, and there were no significant differences in fiber diameters due to Ni2+ content. Core loss mapping using electron energy loss spectroscopy confirmed an even distribution of titanium and relatively uniform nickel in the fibers. It was found that doping with 0.5 mol.% Ni2+ decreased the rutile content, while doping with 1 mol.% Ni2+resulted in a pure anatase phase with a significantly increased specific surface area (36.6 m2/g). Further increase in Ni2+ content (3–10 mol.%) not only prolonged the response of TiO2 nanofibers to visible light, but also increased the specific surface area (49.5 m2/g), decreased crystallite size (7 nm), and increased rutile content in TiO2 (33 wt.%). Photoluminescence analysis revealed that doping TiO2 with different amounts of Ni2+ leads to a gradual decrease of emission spectra intensity and red shift in the maxima positions. The XPS results confirmed that as the Ni2+ content enlarged, the Ti2+ and Ti3+ content increased significantly, effectively promoting the formation of oxygen vacancies. Raman analysis showed that an increase in nickel content (3–5 mol.%) led to a decrease and shift in peak intensity due to Ti3+ formation and also the possible presence of NiTiO3 phases. HRTEM analysis showed that Ni was doped into the substitution sites of both the anatase and rutile TiO2 lattice but had a stronger influence on the distortion of the anatase phase. The photocatalytic activity of Ni-doped TiO2 nanofibers was explored by analyzing the degradation of an antibiotic, oxytetracycline, monitored in laboratory conditions under visible light irradiation. After 60 min of irradiation, the degradation of OTC with 1Ni-TiO2 reached 76.4 % and with 10Ni-TiO2 70.5 %.

Bright cyan emission from Eu-Doped borosilicate glasses by optimizing reduction of Eu3+ to Eu2+ in ambient atmosphere

Although substantial strides have been made in exploring the blue and red emissions of amorphous glass under near-ultraviolet excitation for LEDs purpose, the lack of the cyan emission heavily hinders the full spectra LED towards high-quality application. Addressing this cyan gap in white-light LED technology calls for the doping of Eu2+ as the doping center for its highly efficient luminescence. However, Eu3+ as an oxidation state of europium ions poses a critical challenge in effectively reducing to its reduction state. A popular method for reduction involves using mixed gases such as N2/H2 or CO gases in a reaction container, yet this approach brings about environmental pollution and increases production costs. In this work, we proposed a novel strategy that bright cyan emission can be achieved in Eu-doped borosilicate glasses by optimizing reduction of Eu3+ to Eu2+ in ambient atmosphere. It is observed a gradual increase in the band emission intensity associated with the reduced Eu2+, accompanied with a concurrent decrease in the sharp peak intensity linked with Eu3+ with the growing Si3N4 content. The effect of both melting temperature and synthesis time on reduction effect on the reduction of Eu3+ to Eu2+ ions were also investigated. It is revealed that either longer synthesis times or higher melting temperatures diminished the efficient reduction of Eu3+ to Eu2+ ions during the first-melting. Expanding on the Si3N4 reduction method, we employed an external bamboo charcoal approach to produce Eu-doped borosilicate glass under various synthesis times during the secondary melting. The results show that longer synthesis times attributed to the reduction effect. Finally, the optimized cyan-emitting glass sample is featured with emission wavelength of 486 nm, a transmittance of 84 %, and a quantum yield of 37.97 %. All the significant results are paving the solid way to prepare cyan-emitting glasses in the future.

Study on the dyeing properties of Chinese fir with Cinnamomum camphor pigment by premordant dyeing

ABSTRACT Wood staining can improve the quality of Chinese fir. In this study, Cinnamomum camphora natural plant pigment was used as a substitute for synthetic dyes to stain Chinese fir, and the staining performance was enhanced through pre-mordanting with alum. The dyeing effects of direct dyeing and mordant dyeing were compared, and the factors and levels influencing color difference, wash fastness, and light fastness were investigated through an orthogonal experimental design. The results showed that mordanting time had the greatest influence on color difference and lightfastness, while mordanting temperature had the greatest influence on washfastness. After pre-mordanting, the washfastness of Chinese fir improved to a level of 2–3, while the improvement in lightfastness was not significant. Pre-mordanting increased the dye uptake rate by 6.67%. Scanning electron microscopy revealed that NaOH pretreatment opened the wood pores and increased the flow channels for dye liquor. Infrared analysis indicated that O-H in wood fibers formed complexes with Al3+ in the mordant, resulting in a decrease in the characteristic peak intensity of O-H. X-ray diffraction analysis showed that the attractive effect of Al3+ vacant orbitals on O-H partially influenced the ordered arrangement structure in the crystalline region.

INCREASED DISSOLUTION RATE OF ACECLOFENAC BY FORMATION OF MULTICOMPONENT CRYSTALS WITH L-GLUTAMINE

Objective: The objectives of this research were to improve the solubility as well as the rate of dissolution of aceclofenac (ACF) through the formation of multicomponent crystals (MCC) with L-glutamine (LGLN) as a coformer and following the liquid-assisted grinding (LAG) technique.&#x0D; Methods: MCC of ACF and LGLN was formed by Liquid Assisted Grinding (LAG) technique. Powder X-ray Diffractometer (PXRD), Differential Scanning Calorimeter (DSC), Fourier Transform Infrared (FT-IR) spectrometer, Particle Size Analyzer (PSA), and Scanning Electron Microscope (SEM) were used for MCC characterization. Solubility and dissolution test were determined using ultraviolet-visible (Uv-Vis( spectrophotometer.&#x0D; Results: The results showed a decrease in the diffraction peak intensity, melting point, and enthalpy of fusion. FT-IR analysis showed a non-significant wavenumber shift compared to intact components. These characterizations showed that MCC formed a eutectic mixture. SEM and particle size analysis showed a homogeneous particle rod shape and decreased particle size. ACF's solubility in MCC increased 2.21 times more than intact form. MCC's dissolution rate increased by 5.34 times and 5.56 times, respectively, after 60 min in phosphate buffer pH 6.8 and CO2-free distilled water.&#x0D; Conclusion: The formation of MCC of ACF and LGLN considerably enhances ACF's solubility and dissolution rate.

Effect of Anodizing Voltage and Tobacco Extract Addition on the Structure of Porous Anodic Aluminum Oxide (PAAO) Layer

Porous Anodic Aluminum oxide (PAAO) is a porous oxide layer resulting from anodization. The structure of PAAO is influenced by anodization parameters, i.e., voltage and electrolyte composition. Increasing anodization voltage can affect the process of pore formation and oxide growth during anodization. Adding additives such as ethanol, propanol, and polyethylene glycol (PEG) can increase pore regularity and affect the structure of PAAO. In this study, tobacco extract (TE) was added to the oxalic acid-based anodizing solution. TE has many active compounds that may affect pore formation and oxide growth. Morphological analysis shows decreased pore diameter when adding tobacco extracts with concentrations of 0, 0.1, and 0.5 g/L, namely 43.92, 41.42, and 37.8 nm at anodization voltage 40 V. In anodization with a voltage of 60 V, a decrease in pore diameter was obtained with 46.47, 34.24, and 26.8 nm for adding tobacco extract 0, 0.1, and 0.5 g/L. The thickness of PAAO increases from 6.45 µm to 16.87 µm with increasing anodization voltage and tobacco extract concentration. The increase of tobacco extract concentration can lead to the decrease of the XRD peak intensity, where the sequence of the most significant decrease was observed for the peaks of (111), (220), (200), and (311), respectively. A decrease in the intensity ratio of (111) and (220) AAO peaks indicates the influence of tobacco extract on the anodization process. Further thermal analysis by Thermo-gravimetric (TG) shows an increase in mass loss from 1.47 to 5.37% with increasing tobacco extract concentration from 0 g/L to 0.5 g/L. TG results indicate the incorporation of tobacco extract in the inner pore wall.

Enhancing the solubility and dissolution rate of piperine via preparation of piperine–hydroxypropyl methylcellulose 2910 solid dispersion system using freeze-drying method

Context: Piperine is the main secondary metabolite isolated from the family Piperaceae. This biologically active ingredient has many pharmacological effects, though its low water solubility limits its absorption in gastrointestinal fluid. Aims: To improve piperine’s solubility and dissolution rate by incorporating it into a solid dispersion system with the hydrophilic polymer hydroxypropyl methylcellulose (HPMC) 2910 via the freeze-drying method. Methods: Three different piperine:polymer ratios – 1:1, 1:2, and 2:1 (w/w) – were prepared. A physical mixture was also prepared in a 1:1 (w/w) ratio for comparison. The physicochemical properties of the samples were characterized by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) analysis, Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). The solubility and dissolution tests were conducted in distilled water. Results: The solid dispersion characterization indicated a decrease in the melting points and endothermic peaks in the DSC analysis, a decrease in peak intensity in the PXRD patterns, no chemical interactions between active substances and polymers in the FTIR analysis, and significant morphological changes in the SEM analysis. The solubility test revealed the highest increase in piperine solubility (7.88-fold increase) for the 1:2 solid dispersion. Moreover, the 1:2 solid dispersion in the dissolution test led to the greatest amount of dissolved piperine (56.445 ± 1.13%). Conclusions: The piperine–HPMC solid dispersion system improved the solubility and dissolution rate of piperine.

Enhanced Thermoelectric Performance of CoSb3 Based Incorporated with Reduced Graphene Oxide

Thermoelectric is one of the energy harvesters that can convert heat energy into electrical energy currently being developed. One of the thermoelectric materials most studied is Antimony Cobalt (CoSb3). The unique crystal structure, high carrier mobility, and high electrical conductivity of CoSb3 -based skutterudite is considered promising thermoelectric material for medium-temperature thermoelectric applications. A comprehensive study is needed to investigate scientific information and its application by modifying the combination of the two phases by making CoSb3 /rGO nanocomposites. CoSb3 was synthesized using the polyol method, which was then composited with rGO material and made into thin films. It is found that adding rGO increases electrical conductivity. The addition of rGO composite showed that the local crystal structure experienced a decrease in peak intensity in the (0 1 3) plane. It was found that the grains were agglomerated. Furthermore, adding the rGO gives rise to a change in the size of the gr ins. The resulting electrical conductivity range from (1.4–4)×103 Ω-1 cm-1 at room temperature. While at 320 K, the value of the Seebeck Coefficient composite rGO 20% is around 1.2 V/K.

Model-based reinforcement learning for robot-based laser material processing

Articulated robotic arms in laser material processing require precise motion planning. Traditional motion planning methods face challenges in trajectory accuracy. This study demonstrates model-based reinforcement learning as an effective approach for motion planning of these robotic arms. The process involves training a neural network trajectory model based on Pilz Industrial Motion Planner, followed by training an agent to optimize motion by adjusting joint velocities.The study compares Proximal Policy Optimization and Soft Actor-Critic algorithms to the baseline Pilz motion plan. Results show that model-based reinforcement learning improves accuracy in x-direction, reducing mean absolute error to 1.75 × 10−3 m from 6.37 × 10−3 m. However, it slightly increases z-direction mean absolute error, from 6 × 10−6 m to 2.5 × 10−4 m. This leads to an increase in on-surface beam radius, from 2.9 × 10−5 m to 3.3 × 10−5 m, and decrease in peak intensity of 22.77 % compared to baseline.These results highlight reinforcement learning’s potential to enhance trajectory accuracy in motion planning, advancing robot-based laser material processing.

Green Synthesis and Characterization of Silver Nanoparticles (AgNPs) and L-cysteine-capped AgNPs with Foeniculum vulgare seed extract for Colorimetric Hg2+ Detection

In this study, silver nanoparticles (AgNPs) and L-cysteine-capped AgNPs were synthesized separately using Foeniculum vulgare seed extract as the reducing agent and L-cysteine as the capping agent, which were characterized by ultraviolet–visible spectrophotometer (UV–vis), Fourier Transform Infrared spectrophotometer (FT-IR), X-ray diffractometer (XRD), and transmission electron microscopy (TEM). The utilization of the synthesized nanomaterials as colorimetric sensors for the detection of Hg2+ ions was also investigated. In this context, it was determined that L-cysteine-capped AgNPs exhibited better performance in the colorimetric Hg2+ detection in regards to sensitivity, selectivity, and applicability in real samples. It was observed that the colorimetric detection method was based on the disappearance of the brown color of the nanomaterial-contained colloidal solution and thus the decrease in the LSPR peak intensity. The method of the colorimetric Hg2+ detection with L-cysteine-capped AgNPs showed the good regression coefficient with the minimum detection limit of 0.36 μM in the linear Hg2+ concentration range of 1.0-10 μM, which indicated the competitive results compared to the latest reported colorimetric sensors in the literature. According to the obtained results, it has been concluded that the studied method enables to detection of Hg2+ ions colorimetrically via L-cysteine-capped AgNPs in a sensitive, selective, applicable in real samples, cheap, and easy way.

Emerging CeO2/Bi24O31Cl10/Bi3O4Cl ternary-hetero-assembly nanophotocatalyst for superior sunlight-irradiated photo-elimination of quinolone antibiotics: Microwave combustion-assisted sono-induced-hydrothermal synthesis

This study aimed to introduce emerging CeO2/Bi24O31Cl10/Bi3O4Cl ternary-hetero-assembly nanophotocatalysts through the fabrication process of microwave combustion-assisted sono-induced-hydrothermal (MCSH). Various characterization techniques were conducted to determine the properties of the resulting nanophotocatalysts synthesized at different weighted ratios. The CeO2/Bi24O31Cl10/Bi3O4Cl-MCSH nanophotocatalyst which weighted ratio of CeO2 to Bi24O31Cl10/Bi3O4Cl is 3:1 showed a broad absorption range in the sunlight region and demonstrated tremendous performance in the removal of emerging contaminants such as norfloxacin (NOR) (87.6%), levofloxacin (70.2%), ofloxacin (66.2%) and ciprofloxacin-HCl (57.9%) after 180 min irradiation. In contrast, the CeO2/Bi24O31Cl10/Bi3O4Cl (3:1)-MCH sample, without ultrasound irradiation nanophotocatalyst, showed lower photocatalytic destruction such as norfloxacin 77.3%. As a result, it can be said that the presence of ultrasonic energy has led to particle size reduction and increased dispersion, resulting in a decrease in peak intensity based on XRD analysis. The DRS analysis showed that the optimal nanocomposite exhibited two distinct absorption edges at 415.6 and 487.8 nm, indicating that the desired composite had indeed been formed as well as the TEM signifies a consistent and evenly dispersed distribution of CeO2 particles and Bi24O31Cl10/Bi3O4Cl plates of nanomaterial's prepared with ultrasound energy. The BET-BJH of surface characteristics and pore distribution indicates that the pores' dimensions in the CeO2-MC, CeO2/Bi24O31Cl10/Bi3O4Cl (3:1)-MCH, CeO2/Bi24O31Cl10/Bi3O4Cl (3:1)-MCSH, and Bi24O31Cl10/Bi3O4Cl -MC samples span meso to macro. The average pore sizes for these nano-sized photocatalysts are approximately 21.4, 23.8, 22.1, and 5.4 nm, correspondingly. The remarkable efficiency and reusable nature of the CeO2/Bi24O31Cl10/Bi3O4Cl (3:1)-MCSH nanophotocatalyst could be assigned to its well-balanced phases and the use of the sonication during its preparation.