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Creatinine is one of the most important biomarkers to detect renal failures. The electrochemical detection of creatinine has been performed using complex enzymatic and non-enzymatic electrode arrays hindering their commercialization. In this work, a new and practical non-enzymatic electrochemical sensor was fabricated depositing copper on carbon paper electrodes by physical vapor deposition (namely Cu/CP). Surface and cross-sectional SEM images demonstrated the deposition of copper over the 3D structure of carbon paper. A thin film was found on the surface, while Cu nanowires with diameters of 180 ± 30 nm were found inside the 3D structure of CP. The thickness of the Cu film on the tubular structures of CP was of 390 ± 40 nm. High-resolution TEM images indicated that the Cu film was integrated by hierarchical structures containing terminal Cu hemispheres of 17.6 ± 2.2 nm. Additionally, interplanar distances from the selected-area electron diffraction pattern demonstrated the presence of Cu0, while Cu2O was also found. Creatinine concentrations in saliva between 16 and 400 µM indicate kidney failure. The Cu/CP electrochemical sensor detected creatinine with linear concentration ranges from 0 to 1000 µM with a r2 = 0.9936. Outstandingly, this sensor presented good reproducibility (RSD = 7.3%), and selectivity to detect creatinine in artificial saliva using interferents like urea, glucose, glycine, ascorbic and uric acids. [ABSTRACT FROM AUTHOR]

The state-of-the-art technology of fabricating printed copper electronics is focussed largely on thermal sintering restricting transition towards heat sensitive flexible substrates. Herein we report a pioneering technology which eliminates the need for conventional sintering. Biopolymer-stabilised copper particles are prepared such that they can be compressed at room temperature to generate air-stable films with very low resistivities (2.05 – 2.33 × 10−8 Ω m at 20 °C). A linear positive correlation of resistivity with temperature verifies excellent metallic character and electron microscopy confirms the formation of films with low porosity (< 4.6%). An aqueous ink formulation is used to fabricate conductive patterns on filter paper, first using a fountain/dip pen and then printing to deposit more defined patterns (R < 2 Ω). The remarkable conductivity and stability of the films, coupled with the sustainability of the approach could precipitate a paradigm-shift in the use of copper inks for printable electronics. [ABSTRACT FROM AUTHOR]

Simple, portable, and low-cost paper-based sensors are alternative devices that have the potential to replace high-cost sensing technologies. The compatibility of the paper base biosensors for both chemical and biochemical accentuates its feasibility for application in clinical diagnosis, environmental monitoring, and food quality monitoring. High concentration of copper in blood serum and urine is associated with diseases like liver diseases, carcinomas, acute and chronic infections, rheumatoid arthritis, etc. Detection of copper concentration can give an early sign of Alzheimer disease. Apart from that genetic Wilson's disease can be detected by evaluating the concentration of copper in the urine. In view of the above advantages, a novel and the highly sensitive paper-based sensor has been designed for the selective detection of Cu2+ ions. The fast and highly sensitive chemiresistive multi-dye system sensor can detect Cu2+ ions selectively in as low as 2.23 ppm concentration. Least interference has been observed for counter ion in the detection of Cu2+. Copper chloride, nitrate, and acetate were used to validate the detection process. This assay provides a very high selectivity of Cu2+ ion over other metal cations such as Na+, Mg2+, Ca2+, etc. The easy preparation and high stability of dye solutions, easy functionalization of the paper-based sensors, high selectivity over other cations, low interference of counter anion, and significantly low detection limit of 2.23 ppm make it an effective Cu2+ ion sensor for real-time application in near future. [ABSTRACT FROM AUTHOR]

The potential reach of point-of-care (POC) diagnostics into daily routines for exposure to reactive oxygen species (ROS) and Cu in aerosolized particulate matter (PM) demands that microfluidic paper-based analytical devices (μPADs) take into consideration the simple detection of these toxic PM components. Here, we propose μPADs with a dual-detection system for simultaneous ROS and Cu(II) detection. For colorimetric ROS detection, the glutathione (GSH) assay with a folding design to delay the reaction yielded complete ROS and GSH oxidation, and improved homogeneity of color development relative to using the lateral flow pattern. For electrochemical Cu(II) determination, 1,10-phenanthroline/Nafion modified graphene screen-printed electrodes showed ability to detect Cu(II) down to pg level being low enough to be applied to PM analysis. No intra- and inter-interference affecting both systems were found. The proposed μPADs obtained LODs for 1,4-naphthoquinone (1,4-NQ), used as the ROS representative, and Cu(II) of 8.3 ng and 3.6 pg, respectively and linear working ranges of 20 to 500 ng for ROS and 1 × 10−2 to 2 × 102 ng for Cu(II). Recovery of the method was between 81.4 and 108.3% for ROS and 80.5–105.3% for Cu(II). Finally, the sensors were utilized for simultaneous ROS and Cu(II) determination in PM samples and the results statistically agreed with those using the conventional methods at 95% confidence. [ABSTRACT FROM AUTHOR]

Improving the performance of porous nickel-based material used widely in the energy field is necessary. Alloying and increasing the specific surface area are essential approaches. This study used rice paper (Chinese traditional calligraphy and painting paper) as biomass templates to prepare hierarchical porous Ni and Ni-Cu foils (Nip and NiCup) with a thickness of about 60 μm by impregnating and high-temperature reduction process. The Ni3S2/Nip electrodes were prepared by an in situ-grown Ni3S2 nanosheet array on the struts of Nip via a hydrothermal process. Two modification methods using Cu-added alloying and Ni-S nanosheet growing were compared to determine their effects on the microstructure, phase, and performance in methanol oxidation (MOR) and urea oxidation (UOR). The results showed that both alloying effects and morphology control can promote MOR and UOR. Compared to the current density value of Nip at 0.8 V, the values of the preferred Ni10Cup and nanosheet array Ni3S2/Nip increased by 24.5% and 27.3% for methanol oxidation and by 15.4% and 38.4% for urea oxidation, respectively. Adding Cu helped to improve electron transfer and facilitated the transition from Ni2+ to Ni3+. The large specific surface area of Ni3S2 nanosheets provided more active sites for the reaction. Compared to Ni10Cup, Ni3S2/Nip with a lower impedance value exhibits better electrocatalytic performance and stability, achieving peak current densities of 269.7 mA cm−2 (MOR) and 303.9 mA cm−2 (UOR) at 0.8 V, maintaining 91.2% (MOR) and 102.4% (UOR) of the initial peak current density after 2000 cycles. The foil electrodes obtained under both modification strategies can be used as anode material in portable cells, and might also be applied to the oxidation of other small organic molecules. [ABSTRACT FROM AUTHOR]

Iron and copper are essential for all living organisms, and their balance is crucial as both deficiency and excess can cause health problems. Therefore, this study presents a colorimetric method for detecting Fe3⁺ and Cu2⁺ ions in aqueous samples using silver nanoparticles (AgNPs) synthesised from Ocimum sanctum (Tulasi) leaf extract (TLE). It is observed that AgNPs show optimum plasmonic properties at a precursor-leaf extract ratio of 1:5, reaction temperature of 60 °C and reaction time of 2 h. The AgNPs exhibit the face-centred cubic (fcc) structure and show a surface plasmon resonance peak at 413 nm, hydrodynamic size of 18 ± 5 nm, zeta potential of − 25.5 mV and particle size of 57 nm. FTIR spectra confirm the stabilisation of AgNPs. It is worthy to note that, AgNPs exhibit selective detection of Fe3⁺ and Cu2⁺ over other metal ions and the detection mechanism is proposed based on the reduction potential values. The quantitative detection range for Fe3⁺ and Cu2⁺ are found to be 0–800 μM and 0–600 μM, with the detection limits of 9.1 µM and 19.5 µM, respectively. Additionally, AgNP-based paper sensors for Cu2⁺ detection show qualitative and quantitative colorimetric performance with a detection limit of 23.1 µM. These findings suggest that both AgNPs solution and AgNP-based paper sensors are the potential candidates for metal ion detection. [ABSTRACT FROM AUTHOR]

In the current research work "4-{[1-(2,5-dihydroxyphenyl)ethylidene]amino}-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one" chemosensor (C1) synthesized by condensation reaction using "4-amino-1,2-dihydro-1,5-dimethyl-2-phenylpyrazol-3-one" and "2,5-dihydroxy actophenone" was used as the effective sensor of metal ion. The C1 shows absorption peak at 326 nm due to the C = C bond (π-π* transition), while the absorption peak at 364 nm is caused by the C = O bond (n-π* transition). In the presence of copper, C1 only demonstrated a redshift in absorption peak from 364 to 425 nm. Even in the presence of other competing metal ions, the hypsochromic shift of the absorption band and the quenching of the fluorescence emission intensity were different for detecting Cu2+, in CH3OH-H2O (v/v = 6:4). The capacity of the C1 to bind with Cu2+ was further proved using DFT simulations. The complex C1 + Cu2+ has a HOMO–LUMO energy gap of 2.8002 eV, which is lesser than C1 (2.9991 eV) showing improvement in the stability of the C1 + Cu2+ complex. Using the Benesi-Hildebrand and Scatchard plots, calculated Kb values were to be 47,340 and 48369 M−1 respectively, showing the creation of stable complexation between Cu2+ and C1 with 1:1 stoichiometry. The limit of detection (LOD) for Cu2+ ion was 649 nM. Strip sheets were also built and tested to detect varying amounts of Cu2+ in aqueous solution, and their color change suggested that they might be used for on-site Cu2+ detection in polluted water. [ABSTRACT FROM AUTHOR]

An enhanced ratiometric fluorescence sensor was built for on-site visual detection of doxycycline (DOX) through the interaction with bovine serum albumin on the surface of red emissive copper nanoclusters. Upon the addition of weakly fluorescent DOX, the red fluorescence from copper nanoclusters gradually decreased through the inner-filter effect (IFE), while a green fluorescence appears and significantly increases, forming an interesting fluorescent isosbestic point, which was assigned to DOX due to sensitization effect of bovine serum albumin. On the basis of this ratiometric fluorescence, the system possessed good limit of detection (LOD) of 45 nM and excellent selectivity for DOX over other tetracyclines. Based on these findings, a paper-based sensor has been fabricated for distinct visual detection of trace DOX and combined with smartphone color recognizer for quantitative detection of DOX (LOD = 83 nM). This method shows broad application prospects in environmental monitoring and food safety. [ABSTRACT FROM AUTHOR]

In this study, different methods for incorporating mixed or laminar copper microparticles (CuMPs) during papermaking were evaluated to determine the optimum paper-making process and correlate particle concentration and shape with antimicrobial activity. The addition of CuMPs during the disintegration of dry pulp stage was observed to produce a paper with uniformly distributed CuMPs, as determined through optical microscopy and UV–Vis spectroscopy analyses by measuring absorbance spectra in different areas of papers. Determination of two indices related to the concentration and distribution of copper will allow to predict the copper content in other papers. CuMP-paper samples were evaluated for structural, optical, and mechanical strength properties according to paper industry standards. Quantitative analyses by atomic absorption showed that between 24 and 39% of CuMPs were embedded in the paper fibre, independent of particle type. Finally, antibacterial activity analyses were performed according to ISO 20645 and ISO 20743. The results showed that papers with 0.30 g of incorporated CuMPs have antimicrobial activity, independent of particle morphology, with effects observed towards Gram (+) and Gram (−) bacteria and fungus. Furthermore, the evaluation of antimicrobial activity at different times of exposure to the microorganisms showed differences in effects that were dependent on the shape of the CuMPs incorporated into paper, where laminar particles exerted a sufficient effect, while no or a slight effect was observed for mixed CuMPs against Aspergillus niger. [ABSTRACT FROM AUTHOR]

It is crucial to understand the effects caused by experimental parameters such as temperature, light, and food type on lab and field-based ecotoxicology experiments, as these variables, and combinations thereof, can affect results. The type of substrate used in exposure experiments, however, is generally assumed to have no effect. This may not always be correct. The metabolic changes in the freshwater crustacean, Austrochiltonia subtenuis exposed to copper, using three common substrates, gauze; toilet paper; and cellulose were investigated. Substrate alone did not affect survival, but each substrate elicited a different metabolic response and adult and juvenile amphipods had different substrate preferences. Several classes of metabolites were shown to change in response to different substrates and toxicant. These included disaccharides, monosaccharides, fatty acids, and tricarboxylic acid cycle intermediates. The results illustrate that metabolomic responses can differ in response to experimental factors that were previously thought not to be significant. In fact, our data indicate that substrate should be viewed as an experimental factor as important to control for as more well-known confounders such as temperature or food, thus challenging the current paradigm. Assuming substrate type has no effect on the experiment could potentially lead to errors in contaminant toxicity assessments. We propose that ideal good practise would be that all experimental factors should be evaluated for their potential influence on metabolomic profiles prior to contaminant response experiments being undertaken. [ABSTRACT FROM AUTHOR]

Conductive Cu patterns were constructed on flexible paper via selectively electroless plating method, which including multistep procedures, namely, 3-aminopropyltrimethoxysilane (APTMS)-modification, selective Cu-seeding and Cu-lines deposition. Herein, the Cu activation process could be divided into two stages: the Cu-absorption in cupric citrate solution and subsequently the Cu-reduction using a roller pen filled with sodium borohydride ink. The interaction of APTMS onto paper was confirmed by FT-IR measurement and the results indicated that the -NH groups originating from APTMS were grafted on the paper. The elemental analysis of the samples in each step was conducted using XPS measurement. Paper-based conductive patterns were investigated by SEM, XRD and Scotch-tape test. SEM images illustrated that the Cu lines on the APTMS modified paper substrate was compact and composed of ball-shaped copper nuclei. Moreover, the Cu lines could be selectively plated on the required area of the paper substrate. XRD analysis showed that the obtained Cu patterns had a structure with Cu (1 1 1) preferred orientation, revealing an excellent electromigration resistivity. The resultant Cu patterns exhibited an admired adhesion to modified paper, while the Cu patterns obtained in absence of APTMS modification suffered a failure in the adhesive Scotch-tape test. The resistivity of copper patterns characterized by the digital four-point probe was 10.3 µΩ cm, which was 6.3 times of the bulk Cu. Meanwhile, paper-based Cu pattern remained excellent conductivity after multifolding. Those results indicated that the method proposed in the present work offered a robust and efficient alternative to manufacture flexible electronics. [ABSTRACT FROM AUTHOR]

Non-thermal plasma (NTP) is a well-known decontamination tool applicable for a wide range of microorganisms and viruses. Since the recent COVID-19 pandemic highlighted the need to decontaminate all daily used items, it is highly desirable to address the applicability of NTP, including its possible harmful effects. To the best of our knowledge, a comprehensive characterization of NTP effects on sensitive materials is still lacking. We investigated the potential damage to common materials of daily use inflicted by air atmospheric NTP generated in Plasmatico v1.0. The materials tested were paper, various metals, and passive and active electronic components modelling sensitive parts of commonly used small electronic devices. The NTP-exposed paper remained fully usable with only slight changes in its properties, such as whitening, pH change, and degree of polymerization. NTP caused mild oxidation of copper, tinned copper, brass, and a very mild oxidation of stainless steel. However, these changes do not affect the normal functionality of these materials. No significant changes were observed for passive electronic components; active components displayed a very slight shift of the measured values observed for the humidity sensor. In conclusion, NTP can be considered a gentle tool suitable for decontamination of various sensitive materials. [ABSTRACT FROM AUTHOR]

The extensive usage and production of copper may lead to toxic effects in organisms due to its accumulation in the environment. Traditional methods for copper detection are time consuming and infeasible for field usage. It is necessary to discover a real-time, rapid and economical method for detecting copper to ensure human health and environmental safety. Here we developed a colorimetric paper strip method and optimized spectrum method for rapid detection of copper ion based on the specific copper chelator bathocuproinedisulfonic acid disodium salt (BCS). Both biological assays and chemical methods verified the specificity of BCS for copper. The optimized reaction conditions were 50 mM Tris–HCl pH 7.4, 200 µM BCS, 1 mM ascorbate and less than 50 µM copper. The detection limit of the copper paper strip test was 0.5 mg/L by direct visual observation and the detection time was less than 1 min. The detection results of grape, peach, apple, spinach and cabbage by the optimized spectrum method were 0.91 μg/g, 0.87 μg/g, 0.19 μg/g, 1.37 μg/g and 0.39 μg/g, respectively. The paper strip assays showed that the copper contents of grape, peach, apple, spinach and cabbage were 0.8 mg/L, 0.9 mg/L, 0.2 mg/L, 1.3 mg/L and 0.5 mg/L, respectively. These results correlated well with those determined by inductively coupled plasma-mass spectrometry (ICP-MS). The visual detection limit of the paper strip based on Cu-BCS-AgNPs was 0.06 mg/L. Our study demonstrates the potential for on-site, rapid and cost-effective copper monitoring of foods and the environment. [ABSTRACT FROM AUTHOR]

The European standard test EN 113 for fungal degradation of solid wood has been adapted for degradation of paper by white rot fungus ( Trametes versicolor). Fungal degradation of paper sheets may potentially be used for screening different wood preservatives on paper instead of solid wood. The paper samples showed higher relative mass losses compared to wood, and samples pretreated with boric acid, copper sulfate and polymerized linseed oil were successfully tested for biodegradation using the paper sheet method. The results on paper degradation were compared with wood, both as wood blocks (according to standard test) and wood cut in sections forming layered structures mimicking paper layers. [ABSTRACT FROM AUTHOR]

A novel microstructured catalyst that consists of Cu/ZnO catalyst powders and ceramic fibers was successfully prepared using pulp fibers as a tentative matrix by a papermaking technique. As-prepared material, called a paper-structured catalyst, possessed porous microstructure with layered ceramic fiber networks (average pore size ca. 20 μm, porosity ca. 50%). In the process of methanol autothermal reforming (ATR) to produce hydrogen, paper-structured catalysts demonstrated both high methanol conversion and low concentration of undesirable carbon monoxide as compared with catalyst powders and pellets. The catalytic performance of paper-structured catalysts depended on the use of pulp fibers, which were added in the paper-forming process and finally removed by thermal treatment before ATR performance tests. Confocal laser scanning microscopy and mercury intrusion analysis suggested that the tentative pulp fiber matrix played a significant role in regulating the fiber-network microstructure inside paper composites. Various metallic filters with different average pore sizes, used as supports for Cu/ZnO catalysts, were subjected to ATR performance tests for elucidating the pore effects. The tests indicated that the pore sizes of catalyst support had critical effects on the catalytic efficiency: the maximum hydrogen production was achieved by metallic filters with an average pore size of 20 μm. These results suggested that the paper-specific microstructures contributed to form a suitable catalytic reaction environment, possibly by promoting efficient diffusion of heat and reactants. The paper-structured catalyst with a regular pore microstructure is expected to be a promising catalytic material to provide both practical utility and high efficiency in the catalytic gas-reforming process. [ABSTRACT FROM AUTHOR]

Cu-doped zinc oxide (Cu–ZnO) nanostructure was prepared using Whatman filter paper as a template by combustion method. For the synthesis of porous Cu–ZnO nanostructures the stoichiometric amount of precursors were impregnated in the filter papers and processed, thermally. The formation of wurtzite phase having crystallite size in the range of 20–24 nm was confirmed by X-ray diffraction (XRD) analysis. The morphological study by field emission scanning electron microscopy (FESEM) and field emission transmission electron microscopy (FETEM) shows size of nanoparticles in the range of 25–50 nm. The optical study shows red shift i.e. extended absorbance in the visible region due to Cu doping. The photoluminescence study of Cu–ZnO results quenching in the photoluminescence peak as effect of Cu doping in ZnO lattice. Considering the extended band gap in the visible region of as synthesized Cu–ZnO, the photocatalytic dye degradation activity of methylene blue (MB) was executed in presence of sunlight irradiation. The effect of salt concentration and PH on dye degradation activity also studied. The highest photocatalytic activity was observed for Cu–ZnO with 4% doping as compared with other Cu–ZnO and ZnO nanostructure. The photocatalytic performance of Cu–ZnO shows complete degradation of MB dye within 30 min for 4% Cu–ZnO nanostructure. The photocatalytic activity obtained is much higher as compare to earlier reports. The synthesis of Cu doped ZnO by paper templated method and its photocatalytic activity is hitherto unattempted. [ABSTRACT FROM AUTHOR]

The electrochemical determination of copper (II), lead (II) and mercury (II) ions has been studied and analyzed in this paper. Preparation of polyaniline functional ink by electronic ink technology was proposed. Screen-printed carbon electrode (SPCE) modified by ethylene diamine tetraacetic acid @ polyaniline/multi-walled carbon nanotube nanocomposite structure was used as an electrochemical sensor by all-printed technology to selectively detect copper, lead and mercury ions. The improved electrode is a great improvement in process simplicity and practicability. Square-wave voltammetry was used to detect the concentration of copper, lead and mercury ions, and the selectivity, sensitivity, reproducibility and stability of the ions were also studied. The detection results show that the modified SPCE electrode has high selectivity, sensitivity and reproducibility. The detection limit of copper ions was determined as 55.4 pM, that of lead ions was 22 pM, and that of mercury ions was 17.8 pM. [ABSTRACT FROM AUTHOR]

The large volumes of water used in wood and paper industries produce substantial amounts of wastewater. These industries are among the most polluting ones in the world; there are large quantities of heavy metals (copper, iron, zinc, etc.) and dyes in the wastewater of these industries, and this wastewater has high levels of COD and BOD. We studied copper removal from the effluents of a wood and paper factory by using a polypyrrole composite consisting of natural Zeolite coated on Perlite (PPy/Perlite). The experiments were performed in a batch system in which effects of various parameters including pH, contact time, adsorbent dosage, and temperature on adsorption were studied. Moreover, SEM and FTIR were employed to identify the structure of the synthesized adsorbent. Results indicated that the maximum copper removal (95%) happened at pH=6, contact time of 12 minutes, and adsorbent dose of 0.4 g/100 mL of the wastewater. Furthermore, copper adsorption capacity of the PPy/Perlite adsorbent improved with increases in temperature and reached its peak at 40 °C. Values of the thermodynamic variables (ΔS, ΔH, ΔG) indicated that copper adsorption could occur in the temperature range of 293-323 Kelvin, and was spontaneous and endothermic. Equilibrium information in the studied range of the initial concentrations of copper and in the temperature range suitably matched the Freundlich isotherm. Evaluation of experimental information for studying the kinetics of copper adsorption by PPy/Perlite revealed that copper adsorption followed the pseudo-second-order kinetic model. [ABSTRACT FROM AUTHOR]

Natural menthol was coated on craft paper by impregnation and studied as volatile corrosion inhibitor for copper in hydrochloric acid environment. The effect of menthol on copper corrosion was studied by gravimetric and electrochemical methods such as potentiodynamic polarization and electrochemical impedance measurements. The results indicate that menthol adsorbs on the metal surface, which protects copper against further corrosion. The adsorption behaviour of menthol on copper surface was found to obey Temkin's adsorption isotherm. [ABSTRACT FROM AUTHOR]

A rapid, sensitive, and highly selective test based on the reaction of copper(I) with thio-Michler’s ketone was developed for the detection and semiquantitative determination of 0.001–2 mg/L copper in natural and potable waters using preconcentration in a portable indicator device. Diffuse reflectance spectroscopy was used to select reagent concentrations for immobilization on paper and study the conditions and performance characteristics of the procedure. [ABSTRACT FROM AUTHOR]

A sensitive biotest for determining acetylcholinesterase inhibitors has been developed on the basis of a paper matrix and an electric eel ( Electrophorus electricus) tissue preparation with high enzymatic activity. Photometric detection at λ = 480 nm based on the ferricyanide reaction (resulting in the formation of copper ferricyanide) was used. The biotest allows the determination of carbamate inhibitors (eserine and neostigmine) and sanguinarine (an isoquinoline alkaloid) at levels of 10−6 to 10−5 M. [ABSTRACT FROM AUTHOR]

Technosols represent the group of soils whose properties and functions were defined by human action, formed from technogenic diagnostic materials. In this study, we use bibliometric techniques to investigate how environmental contamination has been addressed in global Technosol research and identify research trends that contribute to adequate Technosol management. We use 567 papers on Technosols from around the world available in the Web of Science database (2006–2021). Our results indicated that 34.2% of the global research on Technosols was related to environmental contamination, with significant growth over the years (R2 = 0.88). France was responsible for 29.8% of global research in contaminated Technosols. The main contaminant agents in Technosols were the heavy metals and the polycyclic aromatic hydrocarbons (PAHs), with a higher highlight for the first. Among the polluting metals, a greater concern was directed to the Pb, followed, in descending order, by the Zn, Cu, Cd, Ni, Cr, and As. The mining tailings were the main sources of the contaminant material. The combined effects of different pollutants, such as toxic metals and PAHs, in the biological community of Technosols and the combined use of environmental restoration strategies (phytoremediation and uses of organic compound, biochar, and biofertilizers) can be considered the main research trends in contaminated Technosols. Our results can be useful for research institutions and researchers around the world that seek development of strategies for the use and management of Technosols at the global level. [ABSTRACT FROM AUTHOR]

Polyacrylic acid (PAA) applied as surface modifier of zero-valent copper nanoparticles (CuNPs) for electronic printing inks has great potential to replace presently used polymers, because of its favorable technical, environmental and biodegradability characteristics. Continuous synthesis (400°C, 30 MPa) of nanoparticles in supercritical water with short reaction times (1.1 s) was used to form PAA-surface-modified zero-valent (34–46 nm) CuNPs. CuNP particle sizes decreased with an increase in PAA molecular mass (5000, 250,000) and were stable as dispersions in methanol and 1-propanol, respectively. The resistivity of conductive films prepared with CuNPs decreased with an increase in heating temperature. The minimum resistivity of the PAA-modified CuNPs was 1.4 × 10−5 Ω cm at 320°C (PAA25000) and 4.2 × 10−4 Ω cm at 350°C (PAA5000), demonstrating the feasibility of PAA as a dispersant and surface modifier for CuNPs. Polyacrylic acid is thus effective as a surface modifier for zero-valent metal nanoparticles and expands the possible applications in sustainable printed electronics. [ABSTRACT FROM AUTHOR]

An approach was developed for the preparation of cryogenic ground spiked filter papers with Cu and Zn for use as synthetic calibrating standards for direct solid microanalysis. Solid sampling graphite furnace atomic absorption spectrometry was used to evaluate the microhomogeneity and to check the applicability of the synthetic calibrating standards for the direct determination of Cu and Zn in vegetable certified reference materials. The found concentrations presented no statistical differences at the 95% confidence level. The homogeneity factors ranged from 2.7 to 4.2 for Cu and from 6.4 to 11.5 for Zn. [ABSTRACT FROM AUTHOR]

In this work, we designed and synthesized a novel quinolin-based derivative which exhibited signaling behaviors for Cu. Upon the addition of Cu to the solution of the molecule, it displayed an obvious fluorescence quenching in a linear fashion due to the formation of a 1:1 metal-ligand complex. This fluorescent sensor exhibited a rare sensitivity toward Cu(II) (the level of magnitude could be 6 × 10), a rapid response (<10 s) and also high selectivity toward Cu over other metal ions such as Na, K, Ca, Mg, Ba, Fe, Mn, Hg, Pb, Cd, Cr, Co, Zn and Al. Simultaneously, the cell imaging experiments and filter paper test demonstrated its extensive applicability. [ABSTRACT FROM AUTHOR]

In this paper, we have proposed the precise model of coaxial TGVs (CTGVs) which consists of ground-signal signal-ground (GSSG) TGVs. An equivalent electrical model of CTGVs is established and the partial element equivalent circuit (PEEC) technique is used to extract the frequency-dependent impedance parameters. In CTGVs, multi-walled carbon nanotubes (MWCNT) and copper is used as filler material in inner and outer layer. Resistance and inductance of CTGVs is calculated using the PEEC technique for different filler materials. The insertion loss (S21) of CTGVs is determined using the HFSS simulations and is compared analytically in differential mode configurations. S21 is calculated for various geometrical parameters of MWCNT-based CTGVs such as diameter of TGV, pitch between CTGV pair, as well as material properties such as permittivity of SiO2 and benzocyclobutene (BCB) polymers. It is established that MWCNT based CTGV shows improved insertion loss because the conductivity of MWCNT is higher in comparison to copper. [ABSTRACT FROM AUTHOR]

The application of low-level direct electric current (0.15 mA cm−2) as an electrokinetic technique to treat copper-contaminated mesophilic anaerobic granular sludge was investigated. The sludge was obtained from a full scale UASB reactor treating paper-mill wastewater and was artificially contaminated by Cu(NO3)2 or CuEDTA2− with initial copper concentrations of 1000 mg . kg−1 wet sludge. The effect of different electrokinetic cell layouts, pH and EDTA concentrations on the migration of copper and iron during electrokinetic treatment were evaluated. Both, the pH of the sludge cake or the copper complexation with EDTA significantly affected the migration direction of copper. In an ‘open’ cell (sludge cake in direct contact with air), the highest copper mobility was observed at pH 2.5 in both Cu(NO3)2 or CuEDTA2− amended sludge. The highest copper accumulation was at the cathode (22 ± 2)% with CuEDTA2− as contaminant. In a ‘closed’ cell (sludge cake not in contact with air), the highest accumulation was obtained for CuEDTA2− at the anode and amounted to 4(± 0.5)% and 2(± 0.05)%, respectively, at a final pH of 4.2 and 7.7 in the sludge cake. [ABSTRACT FROM AUTHOR]

A multicolor fluorescent nanoprobe has been prepared by loading bovine serum albumin–stabilized copper nanoclusters (BSA-Cu NCs) onto amino clay (AC) and grafting Eu3+ with auxiliary ligand citric acid (Cit). Tetracycline (TC) can coordinate with Eu3+ by β-diketone structure and transfer energy to Eu3+ through antenna effect. When the concentration of TC is in the range 0 to 13 μM, the blue emission intensity of BSA-CuNCs is basically unchanged, and the red emission of Eu3+ is remarkably enhanced due to the coordination with TC. The emission color gradually changes from blue to red under UV lamp (λ = 365 nm). However, when the TC concentration is in the range 13 to 350 μΜ, the internal amino acid residues of BSA sensitize TC, and the emission color gradually changed from red to green. The nanoprobe has rich color, is simple to prepare, portable, and provide a wide detection range. The limit of detection (LOD) is 3.04 nM, which could be used for real-time visual analysis of trace TC in actual samples (lake water, milk, honey, and bovine serum albumin). In addition, a visual test paper has been designed and combined with the color scanning APP of a smartphone to complete the qualitative and semi-quantitative test of TC. BSA-Cu NCs were loaded on amino clay and graft Eu3+ to establish ratiometric fluorescent nanoprobe for TC detection. With the increase of TC concentration, the emission color under 365 nm UV lamp gradually changed from blue to red and then to green, and the color changed obviously and can be observed by the naked eye. The visual test paper and smartphone application detection sensor were developed to realize rapid, convenient, real-time, and visual detection of TC in actual samples. [ABSTRACT FROM AUTHOR]

The dielectric loss of Cu with high thermal conductivity is large at high frequency, which cannot meet the performance requirements in high-integrated circuits. There is an urgent need for materials to reduce its dielectric loss. In this paper, the thermal conductivity and dielectric properties of the AlN coating-Cu substrate system were controlled by changing the N2 pressure. The results showed that the crystallinity of hcp-AlN in AlN coating increased significantly when the proportion of N2 pressure was increased. With the increase of the N2 pressure, the particle size on the surface and the roughness of the coating improved. The AlN coating prepared at high N2 pressure had high dielectric constant and low dielectric loss at high frequency compared to those of the coatings prepared at low N2 pressure. At the same time, the AlN coating prepared under high N2 pressure on the Cu substrate did not decrease the thermal conductivity of Cu substrate. The AlN-Cu system prepared in this paper had high thermal conductivity and good dielectric properties, providing theoretical guidance for integrated circuit packaging and capacitor applications. [ABSTRACT FROM AUTHOR]

Inspired by a paper by Teseletso and Adachi (Miner Econ 8(10):21, 2021), the hypothesis regarding the declining grade of mined copper ore and its possible use as a guide to the future of ultimate recoverable resources (URRs) is tested. As a time axis, cumulative production is taken. Grades can be either grade of cumulative tonnage or annual production grade. Correlation can be linear (grade and tonnage) or semi-logarithmic (grade linear, tonnage logarithmic). We first show that the assumption that the highest correlation is the best guide to the future may be a fallacy. This is the linear correlation between grades of cumulative tonnage and cumulative tonnages since 1959, i.e., 85% of all copper mined historically with a near-perfect correlation approaching one (R2 = 0.97). This leads to implausibly low results of the URR, clearly demonstrating that this trend must shift in the future. Moreover, Teseletso and Adachi's (Miner Econ 8(10):21, 2021) approach using a linear or semi-logarithmic correlation between annual grades with cumulative production leads to erroneous results. Here, the later the calculation of the correlation begins, the lower the extrapolated tonnages are at predetermined, postulated ultimate cutoff grades. This contradicts the accepted knowledge that with lower grades, the resource base is broadened—not narrowed. The only reasonable finding results from the correlation between linear grades of cumulative production with logarithmic cumulative production, i.e., the Lasky relationship, indicating a URR of 7.5 GT Cu, of which 6.7 GT remain to be mined, which is equivalent of close to 325 years of present production. The trend towards declining Cu grades with constant real Cu prices shows the potential for creative solutions for other metal as well. [ABSTRACT FROM AUTHOR]

In order to increase the radiation performance of aperture-type antennas, this paper demonstrates a low-profile, planar, single-layer, three-dimensional (3-D) printable metastructure. The proposed hybridized metastructure is highly transparent as it is made out of novel hybrid meta-atoms having transmission coefficient magnitudes greater than – 0.72 dB and fully complies with the near-field phase transformation principle. The hybridized design approach makes the metastructure planar, low-profile, light in weight, and compatible with additive printing technology. For the proof-of-concept, such metastructure is developed and numerically verified to enhance the radiation performance of a resonant cavity antenna (RCA). With the proposed metastructure, the peak directivity of the RCA is improved by 8.6 dBi (from 11.4 dBi to 20 dBi) at the operating frequency of 12.4 GHz. The aperture efficiency and 3-dB directivity bandwidth of the RCA with the metastructure are 41.46% and 16.5%, respectively. Using readily accessible thermoplastics or polymers and copper with cost-effective fused deposition modeling (FDM) 3-D printing technology, the proposed planar hybridized metastructure can be prototyped commercially. [ABSTRACT FROM AUTHOR]

In this paper, by using a lifecycle perspective, four stages related to the extraction, refining and processing of copper were identified. The different behaviors of countries in the import/export networks at the four stages synthetically reflect their position in the global network of copper production and consumption. The trade flows of four commodities related to the extraction, refining and processing of copper of 142 nations with population above 2 millions based on the UN Comtrade website (https://comtrade.un.org/data/), in five years from 2017 to 2021, were considered. The observed trade flows in each year have been modelled as a directed multilayer network. Then the countries have been grouped according to their structural equivalence in the international copper flow by using a Multilayer Stochastic Block Model. To put further insight in the obtained community structure of the countries, a deep learning model based on adapting the node2vec to a multilayer setting has been used to embed the countries in an Euclidean plane. To identify groups of nations that play the same role across time, some distances between the parameters obtained in consecutive years were introduced. We observe that 97 countries out of 142 consistently occupy the same position in the copper supply chain throughout the five years, while the other 45 move through different roles in the copper supply chain. [ABSTRACT FROM AUTHOR]

The increased attention given to batteries has given rise to apprehensions regarding their availability; they have thus been categorized as essential commodities. Cobalt (Co), copper (Cu), lithium (Li), nickel (Ni), and molybdenum (Mo) are frequently selected as the primary metallic elements in lithium-ion batteries. The principal aim of this study was to develop a computational algorithm that integrates geostatistical methods and machine learning techniques to assess the resources of critical battery elements within a copper porphyry deposit. By employing a hierarchical/stepwise cosimulation methodology, the algorithm detailed in this research paper successfully represents both soft and hard boundaries in the simulation results. The methodology is evaluated using several global and local statistical studies. The findings indicate that the proposed algorithm outperforms the conventional approach in estimating these five elements, specifically when utilizing a stepwise estimation strategy known as cascade modeling. The proposed algorithm is also validated against true values by using a jackknife method, and it is shown that the method is precise and unbiased in the prediction of critical battery elements. [ABSTRACT FROM AUTHOR]

Since it is difficult to obtain 3D micro-electrodes, simple micro-electrodes with round or rectangular cross-sections are used when performing layer-by-layer scanning EDM to machine 3D micro-structures. This process can process 3D micro-structure, which has deficiencies of complicated technical process and low processing efficiency. In the study, copper was used to fabricate 3D micro-electrodes by micro-milling. Using a reciprocating processing method, micro-EDM was conducted with the 3D micro-electrodes to obtain 3D micro-structures. This method had the advantages of high processing efficiency and a simple technical process. The above work is the main content and novelty of this paper. The paper detailedly studied the effects of the stand-off distance and flushing quantity of dielectric fluid on the machining quality of 3D micro-structure. Furthermore, the effects of rough machining and finish machining on the machined surface were also analyzed. Finally, with flushing quantity of 0.3 L/min, stand-off distance of 300 μm, the 3D micro-structures with 5 μm dimensional error were machined in 304# stainless steel by applying 3D micro-electrodes in micro-EDM, which had good processing efficiency and processing accuracy. [ABSTRACT FROM AUTHOR]

The recent multi-analytical study carried out on the Van Eyck's Ghent Altarpiece showed the simultaneous presence of several kinds of metal carboxylates in oil-rich glaze layers. This outcome raised the question whether these carboxylates had already formed during the preparation of the oil binder by the artists. In the case of early-stage formation, they may have had an impact on the drying rate of the resulting oil, as well as on its handling properties. This hypothesis was investigated using a model system of in-house-prepared linseed oil containing incremental concentrations (2–5–10 wt.%) of relevant metal carboxylates (i.e. Ca-, Zn-, Cu-, and Pb oleates and stearates). This paper describes the influence of these type of molecules on the drying rate of linseed oil and, to an extent, on its viscosity. The drying time of the linseed oil, to which one or more metal carboxylates were added, was measured with a drying recorder while the viscosity was assessed with a rheometer. When introduced together, some of these metal carboxylates act in synergy to shorten the drying time with respect to the situation when the same metal carboxylates were added separately to linseed oil. Mixtures of Ca- and Zn-oleates proved to have a larger effect than other binary combinations. Addition of two metal oleates (combination of Ca/Zn/Cu/Pb) reduced the drying time even more. On the other hand, specific combinations of three metal stearates and/or oleates also demonstrated a significant synergistic effect towards increasing the viscosity of the binder. Especially combinations of Ca/Zn/Cu and Ca/Zn/Pb stearates and oleates gave rise to the highest level of linseed oil viscosity increase, when compared to the situation in which the same metal carboxylates were added separately. [ABSTRACT FROM AUTHOR]

The concept, performance, and analyses of distinctive, miniaturized metamaterial (MTM) unit cell addressing the forthcoming Sub 6 GHz 5G applications are presented in this paper. Two circular split-ring resonators (CSRR) with two parallel rectangular copper elements in front of the design and a slotted square element in the background make up the suggested metamaterial. It has a line segment with tunable features that is positioned in the center of the little ring copper structure. The suggested design offers a significant operating frequency band of 220 MHz together with a resonance of transmission coefficient S21 at 3.5 GHz. Furthermore, in two (z & x) principal axes of wave propagation, wide-range achievement, single/double-negative (S/DNG) refractive index, negative permittivity, and near-zero permeability properties were demonstrated. Through varying central slotted-strip line length, resonance frequencies can be selectively altered. Moreover, the metamaterial has overall dimensions of 9 × 9 mm2 and is composed on a Rogers 5880 RT substrate. In order to create the suggested MTM's equivalent circuit, which shows similar coefficient of transmission (S21), a proposed design's numerical simulation is carried out in the CST micro-wave studio. This simulation is after that put to comparison with manufacturing of the design. [ABSTRACT FROM AUTHOR]

This article investigates the impact of metal-organic frameworks (MOFs) on the performance and stability of perovskite solar cells (PSCs), specifically focusing on the type of metal and the morphology of the MOF. Two types of MOFs, copper-benzene-1,3,5-tricarboxylate (Cu-BTC MOF) with spherical morphology and cobalt-benzene-1,3,5-tricarboxylate (Co-BTC MOF) with rod morphology, are synthesized and spin-coated on TiO2 substrates to form FTO/TiO2/MOF/CH3NH3PbI3/C-paste PSCs. The morphology and size of the MOFs are characterized by scanning electron microscopy (SEM), and the crystallinity and residual PbI2 of the perovskite films are analyzed by X-ray diffraction (XRD). The results show that the Co-BTC MOF PSC exhibits the highest power conversion efficiency (PCE) of 10.4% and the best stability, retaining 82% of its initial PCE after 264 h of storage in ambient air. The improved performance and stability are attributed to the enhanced crystallinity and reduced residual PbI2 of the perovskite film after Co-BTC MOF modification. The paper showcases the immense potential of MOF-based interlayers to revolutionize PSC technology, offering a path toward next-generation solar cells with enhanced performance and longevity. [ABSTRACT FROM AUTHOR]

In this paper, we explore the relationship between refined and scrap copper prices, considering the possibility that this relationship may vary across various products and over time. Building upon the conjecture put forth by Phillip Crowson (Miner Econ 24(1):1-6, 2011), here referred to as the Crowson Conjecture, our study aims to investigate how the substitution between refined copper and copper scrap No. 1 and No. 2 can impact the prices of each other. To achieve this, we develop a theoretical model that allows us to understand the potential influence of substitution between refined copper and copper scrap No. 1 and No. 2 during different time periods. Additionally, we conduct an empirical test using monthly time series data spanning from January 2004 to June 2022, analyzing structural breaks in these prices. Our empirical analysis successfully identifies three distinct structural breaks: January 2004 to August 2009, September 2009 to July 2017, and August 2017 to June 2022. These breaks serve as critical time periods for measuring Granger causality between the examined prices. Interestingly, our findings indicate that the causal relationships between the refined and scrap copper prices change throughout these three analyzed breaks, providing evidence in support of Crowson Conjecture. By shedding light on the evolving nature of the relationship between refined and scrap copper prices, our study contributes to a deeper understanding of the dynamics within the copper market. These insights have implications for market participants and policymakers, enabling them to make more informed decisions regarding pricing and resource allocation strategies. [ABSTRACT FROM AUTHOR]

This paper reports the concentrations of uranium and heavy metals in drinking water samples from Garhwal Himalaya, India determined using LED Fluorimeter and Atomic Absorption Spectroscopy (AAS), respectively. The radiological (carcinogenic) and chemical (non-carcinogenic) risks associated with the consumption of uranium in water were estimated for the public. The concentrations of natural uranium in the analyzed drinking water samples vary from 0 to 21.57 ppb with a mean value of 1.54 ppb. The average concentrations of heavy metals in the analyzed drinking water samples were found to be in the order of iron (3.99 ppm) > zinc (0.32 ppm) > copper (0.04 ppm) > nickel (0.01 ppm) > chromium and lead (Below Detection Level). The estimated risk quantities were found to be lower than World Health Organization (WHO) and United State Environmental Protection Agency (USEPA) guideline values. [ABSTRACT FROM AUTHOR]

The paper presents the results of a study of the microstructure, elemental and phase compositions of the eutectic alloy (wt %): Al–12.5 Si–0.8 Mg–0.4 Mn–0.7 Fe–0.9 Ni–1.8 Cu. A comparison of the microstructure of the alloy obtained at melt cooling rates of 102 and 105 K/s is made. It is shown that an increase in the melt cooling rate leads to the refinement of structural components, a decrease in the volume fraction of primary α-Al dendrites, an increase in the volume fraction of a mixture of eutectic silicon and aluminum, and a decrease in the silicon concentration in the interdendritic space from 23 to 13 wt %. Using energy-dispersive analysis and X-ray diffraction analysis, it was revealed that inclusions of intermetallic compounds Mg5Si6, Al17(FeMn)Si2, and Al3(CuNi)2 are formed at melt cooling rates of 102 and 105 K/s. A mechanism of the formation of a layered microstructure of an eutectic alloy is proposed. An explanation for the formation of X-ray amorphous nanosized particles in the foil layer adjacent to the mold is given. [ABSTRACT FROM AUTHOR]

Iron-gall inks consist of a mixture of vitriols (sulphates of certain metals), gall nut extracts and arabic gum. The association of the iron(II) sulphate present in vitriols, and the gallic acids present in the gall nut extracts induces, after exposure to oxygen, the formation of dark coloured compounds of ink. In addition to iron, this kind of inks contains other metals, such as copper, zinc, and nickel. Among them, copper could be considered the most important because, owing to its catalytic ability, it can be involved in the processes concerning formation and stability of iron complexes, which are responsible for the ink dark colour. For this purpose, four different iron-gall inks containing increasing amounts of copper sulphate were prepared according to a traditional receipt and applied on paper supports. The ink-stained paper specimens were subjected to an intense analytical program to investigate their chemical and physical modifications after artificial ageing (both temperature/humidity and ultraviolet light ageing). The role of copper in the iron-gall inks was evaluated using optical microscopy, colorimetric measurements, X-ray fluorescence (XRF), X-ray diffraction analysis (XRD), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX) and Fourier transform infrared spectroscopy (FTIR). For the evaluation of the oxidation state of iron and copper, X-ray absorption spectroscopy (XANES) was used. All results indicate that the presence of copper in iron-gall ink causes colour variation, affects the migratory behaviour of iron in the paper, increases the formation of secondary products particularly when ageing process based on temperature/humidity variations is considered. [ABSTRACT FROM AUTHOR]

Cold spray (CS) is a thermal spray method that deposits solid particles at high velocity at about room temperature using gases such as nitrogen or helium. Despite of CS's unique advantages, it is expensive to operate due to its high gas consumption and the need for small particle sizes for deposition. To enhance cost-effectiveness, liquid cold spray (LCS) has been developed with the capability of depositing large particles with a wider size cut by using water as a propellant. Though LCS has demonstrated success in manufacturing copper coatings, it raises questions about how wetting of particles and/or substrate surfaces can affect adhesion. This paper addresses these concerns using a finite element method based on elastic–plastic theory. Results demonstrate that wetting the deposited particle reduces both particle and substrate deformation. Water film wetting the particle primarily affects the bonding area due to its presence in the interfacial area between the particle and substrate. In order to avoid interfacial water, this paper investigates the effect of four parameters as follows: particle velocity, particle size, water film thickness, and water temperature. The results demonstrate that the volume of interfacial water is reduced by increasing particle impact velocity and particle size and decreasing water film thickness. A rise in water temperature does not affect the amount of interfacial water; however, evaporation of interfacial water can increase. [ABSTRACT FROM AUTHOR]

Nickel (Ni) and copper (Cu) are the most prevalent metals found in the soils in the Greater Sudbury Region (Canada) because of smelting emissions. The main objectives of the present study were to (1) determine the toxicity of nickel (Ni) and copper (Cu) at different doses in Betula papyrifera (white birch), (2) Characterize nickel resistance mechanism, and (3) assess segregating patterns for Ni and Cu resistance in B. papyrifera populations. This study revealed that B. papyrifera is resistant to Ni and Cu concentrations equivalent to the levels reported in metal-contaminated stands in the GSR. Resistant genotypes (RG) accumulate Ni in roots but not in leaves. Moderately susceptible (MSG) and susceptible genotypes (SG) show a high level of Ni translocation to leaves. Gene expression analysis showed differential regulation of genes in RG compared to MSG and SG. Analysis of segregation patterns suggests that resistance to Ni and Cu is controlled by single recessive genes. [ABSTRACT FROM AUTHOR]

The primary goal of this paper is to study a few advantages of bulk nanoparticles of Cu-doped SnO2 using the solid-state reaction method. Many innovative methods were employed to evaluate the special tuning of the bandgap and other structural and morphological properties of the material. X-ray diffractometer (XRD) confirmed that tin oxide has a rutile-type tetragonal-shaped structure with space group P42 / mnm. The average crystallite size was calculated which was found to increase from 53 to 80 nm by increasing the Cu-doping from x = 0 to x = 0.30. SEM images specified that nanoparticles are inhomogeneous and densely close to each other and the average particle size was found to be in the range of ~225–430 nm. Transmission electron microscopy (TEM) images showed the grains present in a few cubic and spherical shapes and grain size was increased (~20–90 nm) with doping of copper in the SnO2 lattice. UV–Vis spectroscopy showed that the band gap increased from 3.531 to 3.701 eV for pure SnO2 and Cu-doped SnO2, respectively. XPS identified the electronic state of Sn as well as Cu atoms as 4 + and 2 + , respectively. Raman spectroscopy showed that only three vibrational modes, i.e., A1g, B2g and doubly degenerate Eg, exist in a sample. [ABSTRACT FROM AUTHOR]

The Magnetic Pulse Compression (MPC) system is a well-established method for generating high-peak-power, short-duration voltage pulses, commonly used in pulse power supplies (PPS). Traditionally designed for a fixed high repetition rate, this paper explores the techniques and outcomes of variable repetition rate operation in an MPC-based PPS used to excite a copper vapor laser (CVL). Specifically, the PPS, initially designed for 9 kHz operation, is tested at three different rates: 8 kHz, 9 kHz, and 10 kHz. A mathematical model is developed, and experimental modifications are presented in this paper. The study investigates the impact of repetition rate variations on CVL parameters, particularly phantom current (Phantom current: 47% at 8 kHz, 54% at 9 kHz, and 51% at 10 kHz). Phantom current reduces at 10 kHz due to improved impedance matching. At 8 kHz, the laser output is 24W, increases to 30W at 9 kHz and 43W at 10 kHz with a plane-plane resonator configuration. This trend extends to the master oscillator power amplifier (MOPA) at 10 kHz, resulting in a 50% increase in optical power output compared to 9 kHz. This improvement at 10 kHz applies to various parameters, including optical pulse characteristics, average power, electro-optic efficiency, energy per pulse, reduced jitter, and impedance matching. [ABSTRACT FROM AUTHOR]

Schiff base compounds were reported to make a complex with Cu2+ and Ag+ and subsequent reduction produced Cu0 and Ag0 nanoparticles separately via UV irradiation. Here, we synthesized a Schiff base, which initially formed a complexation with Cu2+ and made Cu0 nanoparticles after 8 h aging. In that reaction mixture, addition of Ag+ resulted in Ag0 nanoparticles. Emissive semi-carbazone (a Schiff base synthesized from semicarbazide and salicylaldehyde) was employed for the first time to selectively and sensitively detect Cu2+ (linear range of detection 10–4 to 5 × 10–8 M and limit of detection 13 μM) with the formation of copper oxide nanoparticles via complexation–reduction method. The introduction of Ag+ in it produced Ag0 and Cu0 (CuO via aerial oxidation) nanoparticles with a gigantic increase of fluorescence to obtain selective and sensitive Ag+ detection (linear detection range 10–3–10–7 M, and limit of detection 7. 7 μM). Thus, Cu2+ and Ag+ were detected based on turn-off/on fluorescence in one pot. As the evolution of copper and silver nanoparticles was the fundamental reason for sensing, response time is similar to the stable fluorescence behavior of oxidized SC (capping agent) with in situ generated copper and silver nanoparticles. CuO-induced fluorescence quenching was due to the formation of the trapped plasmon, while Ag+-induced fluorescence enhancement was owing to the lightning rod effect. The synergism of Cu and Ag was also investigated in this paper as a driving force of the lightning rod effect for the first time. Both the metals (Cu and Ag) were estimated in natural water, justifying the utility of the sensing platform for practical applications. Besides, the evolution of brilliant red color with semi-carbazone for Ag+ was employed for the colorimetric sensing of Ag+. [ABSTRACT FROM AUTHOR]

This paper presents the results of the first X-ray fluorescence (XRF) investigation conducted on three late medieval chalices associated with Ireland: the Ó Learghusa chalice, auctioned as medieval Irish in 2021, does not have a confirmed provenance; the de Burgo-O'Malley chalice, dated 1494, and the TP-IEP chalice, dated 1589, both of Irish provenance. This study effectively addressed the knowledge gap concerning Irish medieval silver chalices composition. The analysis revealed that both the Ó Learghusa and de Burgo-O'Malley chalices were crafted from a silver-copper alloy and adorned using a fire-gilding technique. The blue and green enamels on the de Burgo-O'Malley chalice were found to be constituted by cobalt and iron/copper glasses, respectively. In contrast, the TP-IEP chalice exhibited a more intricate structure, being a composite object with partial silver gilt and with the bowl and base possibly made of a ternary silver-copper-gold alloy. The TP-IEP chalice's knop displayed glass, simulating gems with transparent, blue, and purple colorations. XRF analysis allowed identification of lead-potash glass, while the red glass displayed a rich iron content and was identified as soda-lime glass. The analysis allowed concluding that the de Burgo-O'Malley chalice had retained its original condition, including its original gilding and enamels, while the Ó Learghusa and TP-IEP chalices appeared to have undergone refurbishment. These significant discoveries contribute to a deeper understanding of the historical context and artistic craftsmanship behind these late medieval chalices, shedding light on their unique stories within Irish art and history. [ABSTRACT FROM AUTHOR]

Different manufacturers do not produce the same quality of children's Ca–Fe–Zn oral liquid due to different production materials and processes. To improve the phenomenon of counterfeit and imitation oral liquid on the market and effectively monitor its quality, laser-induced breakdown spectroscopy (LIBS) fingerprinting with sample preparation methods can provide a tool for real-time and rapid detection of oral liquids. The sample preparation methods include filter paper adsorption (FPA), filter paper adsorption with elemental Cu (FPA with Cu), adding dropwise to glass slides (ADS), adding dropwise to glass slides with elemental Cu (ADS with Cu), and gel preparation (GP). This work collected LIBS spectrum of oral liquids from eight manufacturers. The model for eXtreme Gradient Boosting (XGBoost) was constructed for classifying oral liquids based on five sample preparation methods. The accuracy was 91.25, 94.17, 55.42, 91.25, and 91.29%, respectively. The results show that the FPA method is more straightforward, efficient, and less affected by the specificity of the color of the sample. Both ADS and GP are susceptible to the color characteristics of the sample and are not well suited to the direct detection of transparent liquids. This work demonstrated that oral liquids could be discriminated by analyzing LIBS spectrum combined with the XGBoost model. Additionally, sample preparation, like the simple FPA method, can improve the accuracy of LIBS classification. [ABSTRACT FROM AUTHOR]

Catalytic conversion of glycerol to lactic acid has been considered as one of the effective ways to solve the problem of glycerol surplus. In this paper, we reported a facile synthesis of Cu/ZnO/C by direct calcination of Cu-supported zeolitic imidazolate framework(ZIF-8), and the performance of the catalysts for converting glycerol to lactic acid were investigated. The properties of Cu/ZnO/C catalysts were characterized by XRD, BET, SEM and TG techniques. The results showed that nano-copper was distributed uniformly on the porous carbon carrier. The zinc oxide after thermal treatment provided abundant metal active sites and had synergistic effect with nano copper. In addition, the lactic acid selectivity of 84% was obtained at the glycerol conversion of 95.1% at 230 °C, 1.5 MPa and 15% copper loading for 6 h reaction. Moreover, the yield of lactic acid still remained above 80% after being recycled four times. [ABSTRACT FROM AUTHOR]

Purpose: This paper presents the design, development, and performance analysis of a Two-Degree-of-Freedom Vibration-Based Electromagnetic Energy Harvester (TDOF VBEEH). The purpose is to enhance power output and widen the operational frequency band of the harvester. In the literature, various techniques such as mechanical amplification, resonance tuning, and nonlinear oscillations etc., have been explored. The proposed TDOF VBEEH incorporates a mechanical amplifier in series with a traditional Single-Degree-of-Freedom (SDOF) VBEEH. Methods: The paper derives an analytical expression for the average power output of the TDOF VBEEH based on the principles established by Tang and Zuo. The effects of mass ratio, electrical damping ratio, and tuning ratio on the power output and effective operational frequency band of TDOF VBEEH have been studied to provide design guidelines for TDOF VBEEH. Also, the experimental analysis is conducted to examine the effects of a purely resistive load and mass ratio on the average harvested power of the TDOF VBEEH. The study utilizes a specially designed setup for TDOF VBEEH. Furthermore, by employing the method of surface plots and contour diagrams, the global optimum values of power output for the TDOF VBEEH under various electrical damping ratios and normalized excitation frequencies have been determined. Results: The results demonstrate that the appropriate selection of mass ratio, tuning ratio, and electrical damping ratio can enhance the power output and widen the effective operational frequency band of the TDOF VBEEH. Notably, the maximum harvested power is achieved when the electrical circuit connected to the harvester has a resistive load of approximately 1500 Ω, which aligns with the internal resistance of the copper coil. The results show that the increased power output is attainable over a widened operational excitation frequency band compared to the traditional Single-Degree-of-Freedom (SDOF) VBEEH. From the comparison of the experimental and analytical results, it is seen that the TDOF VBEEH performs better than the SDOF VBEEH when the parameters are properly chosen. Conclusion: These findings highlight the superior performance and potential of TDOF VBEEHs over SDOF VBEEHs, emphasizing the importance of parameter selection in maximizing power output and widening the operational frequency band. Also, the findings offer valuable design guidelines for selecting system parameters when developing TDOF VBEEHs to power small electronic devices. [ABSTRACT FROM AUTHOR]