Sulfide Particles Research Articles

An experimental and modelling approach to proclaim sustainable machining using avocado oil-based nano-cutting fluids

Higher-end science and technology facilitate the human community with a sophisticated life despite it curses by abundant pollution. The alarming demand for sustainability pressurizes the manufacturing sector to ensure sustainable manufacturing. Since Molybdenum di sulfide (MoS2) and avocado oil are known solid and liquid lubricants respectively, hence, it is a worthwhile attempt to implement the bio-based degradable avocado oil enriched with nano Molybdenum di sulfide (nMoS2) particles as a potential machining fluid for CNC-end milling. Different proportions of avocado oil and nMoS2 were used to synthesise four distinct machining fluids to assess the individual impact of avocado oil and nMoS2 particles. The emulsification and sonication were employed to synthesise the fluids. A hybrid Grey Relational Analysis (GRA) coupled with Principal Component Analysis (PCA) was followed to scrutiny the effect of novel machining fluid on machining objectives. The experimental results of physio-chemical properties revealed that avocado-rich 0.5% nMoS2 excels among others. The L16 orthogonal array experiments associated with statistical analysis explored the developed machining fluid (A6W4/0.5) that significantly impacts the machining objectives. The experimental results manifest that nearly 64.87% of surface roughness and 93.3% of tool wear have been reduced during machining in the presence of A6W4/0.5 fluid than A4W6/0.75. The improved performance of the novel machining fluid upholds its potential to replace conventional fluids and ensure green manufacturing.

Synthesized and Commercial Iron Sulfide Particles as Contaminant Sorbents

Synthesized and Commercial Iron Sulfide Particles as Contaminant Sorbents

Nanodots of Transition Metal Sulfides, Carbonates, and Oxides Obtained Through Spontaneous Co-Precipitation with Silica.

The controlled formation and stabilization of nanoparticles is of fundamental relevance for materials science and key to many modern technologies. Common synthetic strategies to arrest growth at small sizes and prevent undesired particle agglomeration often rely on the use of organic additives and require non-aqueous media and/or high temperatures, all of which appear critical with respect to production costs, safety, and sustainability. In the present work, we demonstrate a simple one-pot process in water under ambient conditions that can produce particles of various transition metal carbonates and sulfides with sizes of only a few nanometers embedded in a silica shell, similar to particles derived from more elaborate synthesis routes, like the sol-gel process. To this end, solutions of soluble salts of metal cations (e.g., chlorides) and the respective anions (e.g., sodium carbonate or sulfide) are mixed in the presence of different amounts of sodium silicate at elevated pH levels. Upon mixing, metal carbonate/sulfide particles nucleate, and their subsequent growth causes a sensible decrease of pH in the vicinity. Dissolved silicate species respond to this local acidification by condensation reactions, which eventually lead to the formation of amorphous silica layers that encapsulate the metal carbonate/sulfide cores and, thus, effectively inhibit any further growth. The as-obtained carbonate nanodots can readily be converted into the corresponding metal oxides by secondary thermal treatment, during which their nanometric size is maintained. Although the described method clearly requires optimization towards actual applications, the results of this study highlight the potential of bottom-up self-assembly for the synthesis of functional nanoparticles at mild conditions.

Аспектный анализ механизмов загрязнения сульфидных концентратов шламами из вмещающих пород и обзор методов его снижения

The relevance of the study lies in the need to improve the quality of flotation concentrates when finer grinding of ore is required to reveal a valuable mineral and, as a consequence, increase the amount of particles of the host rock of the sludge fraction. The purpose of the study is to systematize and analyze the existing methods for improving the quality of concentrate during direct flotation from slimed pulp, to determine the most effective and promising of them. The challenges are as follows: to develop a new approach to the problem under study; substantiation of the problem significance and the proposed direction for its solution; to identify new methods for solving the problem of reducing the quality of concentrate during flotation from pulp with a high slime content. The object of the study is the methods for reducing the content of gangue in the froth product. The subject of the study is the scope and effectiveness of the methods for reducing the content of gangue in the froth product. Methodology and research methods used by the authors are: an aspect analysis of scientific information, an analysis of the practice of improving the quality of sulfide concentrates. The article considers the issues of gangue mineral flotation activity, formation of fine and ultrafine gangue particles and their adhesion to flotation-active sulfide particles, and mechanical removal into the foam product. The article presents the results of studies by Russian and foreign scientists, mainly over the past decade. It has been established that the main direction of reducing the mass fraction of gangue in concentrates is the selection of depressants, and their modeling in modern specialized software products is becoming increasingly relevant for creating depressants by modifying existing ones, selecting previously unused chemicals, or creating reagent compositions. This approach allows selecting an individual effective depressant for a specific ore raw material. Selective aggregation of fine and ultrafine mineral particles is of interest for fundamental research. An important direction for reducing the contamination of sulfide concentrates with gangue components is the study of minimizing their mechanical removal, which is influenced by many factors. Little attention has been paid to the study of mechanical removal and the determination of the values of the parameters characterizing this phenomenon in the domestic literature.

Effect of polyphenylene sulfide content on the properties of injection molding bonded NdFeB magnets

AbstractThe effect of polyphenylene sulfide binder content on the properties of injection molding polyphenylene sulfide/NdFeB magnets were investigated. The maximum filling amount of NdFeB magnetic powder was 87.6 wt.‐%, and the mixing process and subsequent injection molding of the polyphenylene sulfide/NdFeB were in good condition. The melt mass‐flow rate of the polyphenylene sulfide/NdFeB granular materials reached 121.7 g/10 min, the compressive strength of the polyphenylene sulfide/NdFeB magnet was 92.18 MPa, and its maximum magnetic energy product reached 5.59 MGOe. The structure and morphology characteristics of polyphenylene sulfide/NdFeB magnets were investigated using scanning electron microscopy and atomic force microscopy. The corrosion behavior of polyphenylene sulfide/NdFeB magnets was also studied using potentiodynamic polarization curves and electrochemical impedance spectroscopy. The results indicated that the injection molding process facilitated the uniform coating of polyphenylene sulfide particles on NdFeB powder, which directly enhanced the corrosion resistance of polyphenylene sulfide/NdFeB magnets. With an increase in polyphenylene sulfide content, the surface of polyphenylene sulfide/NdFeB magnets became more uniform. The corrosion current density of 13 wt.‐% polyphenylene sulfide/NdFeB magnet was approximately one order of magnitude lower than that of 9 wt.‐% polyphenylene sulfide/NdFeB magnet, indicating an improved corrosion resistance of polyphenylene sulfide/NdFeB magnet.

Fabrication of Thin Li6PS5Cl Separators for All-Solid-State Lithium-Ion Batteries

Thin sulfide separators for all-solid-state batteries are crucial to obtain low internal battery-cell resistances, i.e. good battery-cell performances, and high energy densities [1]. A two-dimensional sulfide separator sheet consists commonly of sulfide powder and a polymeric binder. The components are dispersed in a solvent and casted to a given sacrificial substrate. Current challenges for thin separator fabrication include either (1) high costs for commercial sulfide material with very fine particle sizes (<5 µm) or (2) very large particle size distributions (<1 to >100 µm) for “lower-cost” commercial sulfide powders. Since the separator thickness is limited to the diameters of the largest particles, sulfide particles are preferred to be smaller than ~5 µm at an affordable price.In this work, we have produced thin two-dimensional sulfide separator sheets with thicknesses of 20 µm from commercial “lower-cost” Li6PS5Cl material. The powder was wet-ball-milled and dried before it was subjected to paste fabrication and separator casting. Using x-ray diffraction and electrochemical impedance spectroscopy, it was proven that crystal structure and Li-ion conductivities of Li6PS5Cl were unhampered from the mechanical treatment. Secondary electron images of the separator cross-sections revealed ultra-fine particles and the strikingly low separator thickness of 20 µm. An example for such a separator is visible in the attached figure: (a) Photograf of the casted layer on PET foil, (b) SEM top view, (c), cross-section (d) and magnified cross-section of a compressed separator.In the next step, the separator was connected with the (composite) electrodes. Here, we investigated two different approaches to achieve a good mechanical contact and therefore a good electrochemical performance. On the one hand we transferred the separators onto the electrodes by uniaxially or isostatically pressuring. On the other hand we investigated a direct coating of the separator slurry onto metal or composite electrodes.[1] Randau, S., Weber, D.A., Kötz, O. et al. Benchmarking the performance of all-solid-state lithium batteries. Nat Energy 5, 259–270 (2020). https://doi.org/10.1038/s41560-020-0565-1 Figure 1

New insights into the remediation of chromium-contaminated industrial electroplating wastewater by an innovative nano-modified biochar derived from spent mushroom substrate: Mechanisms, batch study, stability and application

To enhance the adsorption and detoxification capabilities of hexavalent chromium (Cr(VI)) using agricultural spent mushroom substrate (SMS), this study pioneered the preparation of biochar (NBC) from Lentinus edodes spent substrate. Subsequently, nano iron sulfide (FeS) particles were integrated onto NBC with carboxymethyl cellulose (CMC) as a stabilizer, resulting in a novel composite biosorption material, nFeS-BC. The adsorption and reduction potential of both NBC and nFeS-BC against Cr(VI) were evaluated through batch experiments, which identified pH as a critical factor influencing adsorption efficiency. Remarkably, nFeS-BC exhibited a superior maximum adsorption capacity (qmax) of 99.57 mg g−1 and a reduction efficiency of 68.65%, outperforming NBC by 277.73% and 211.76% under optimized conditions, respectively. Characterization techniques including Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM-EDX), Fourier Transform Infrared Spectroscopy (FT-IR), and X-ray Photoelectron Spectroscopy (XPS) elucidated the removal mechanisms, predominantly attributed to ion exchange, electrostatic attraction, functional group interaction, and redox reaction. The carbon-oxygen functional groups and nano particles were crucial in the adsorption and reduction processes. Compared with NBC, the incorporation of FeS particles increased the specific surface area and pore volume of nFeS-BC by 130.86% and 183.77%, respectively. nFeS-BC owned a shelf-life of up to ∼3 months of use and exhibited excellent performance in the processing of actual electroplating wastewater with q of 16.71 mg g−1 under 0.1 g L−1 dosage. These findings underscore the potential of nFeS-BC as an efficient material for Cr(VI) removal, presenting a novel adsorbent for the sustainable detoxification of contaminated water resources and the potential for using agricultural waste materials in environmental remediation.

Ethylene vinyl acetate/copper sulphide with near-infrared light active shape memory behavior

This thesis presents the preparation of ethylene vinyl acetate (EVA)-based shape memory polymer composites (SMPC) (EVA/CuS) with near-infrared light photo-thermal response. The composites were prepared using EVA as the matrix material and copper sulphide (CuS) particles as the functional phase. The designability of SMPs was considered in the preparation of these composites. The results demonstrated that the incorporation of CuS, as a functional phase, enhanced the cross-linking degree and augmented the shape memory properties of EVA. Additionally, it served as a photo-thermal functional filler, imparting its photo-thermal properties. It can be observed that as the quantity of CuS particles incorporated into the EVA/CuS composite film increases, the photothermal conversion performance of the composite film improves, the shape fixation rate rises, and the rate of recovery of light-responsive shape memory accelerates. The temperature of the composites increased to 116.7°C in 20 s when the CuS addition was 2 wt% and the NIR light intensity was 0.5 W/cm2. At a NIR light intensity of 0.6 W/cm2, the “U” shape of the sample was restored to a straight state in 30 s, and the shape recovery rate reached 100%. In this experiment, optical near-infrared photostimulation-responsive EVA/CuS composites have been successfully prepared. These composites demonstrate the ability to achieve remote control and fast response of EVA shape memory behavior, offering a new avenue for the preparation of photo-responsive EVA-based shape memory materials.

Phase-Transition-Promoted Interfacial Anchoring of Sulfide Solid Electrolyte Membranes for High-Performance All-Solid-State Lithium Battery.

Solvent-free manufacturing is crucial for fabricating high-performance sulfide-electrolyte-based all-solid-state lithium batteries (ASSLBs), with advantages including side reaction inhibition, less contamination, and practical scalability. However, the fabricated sulfide electrolytes commonly suffer from brittleness, limited ion transport, and unsatisfactory interfacial stability due to the uncontrolled dispersion of the sulfide particles within the polymer binder matrix. Herein, a "solid-to-liquid" phase transition strategy is reported to fabricate flexible Li6PS5Cl (LPSCl) electrolytes. The polycaprolactone (PCL)-based binder (PLI) with phase-transition characteristics fills the gap of LPSCl particles and tightly grafts on the particle surface via ion-dipole interaction, bringing a thin and compact electrolyte membrane (80µm). The simultaneously high Li-ion conducting and electron insulating nature of PLI binder facilitates Li-ion transport and ensures good interfacial stability between electrolyte and anode. Consequently, the sulfide electrolyte membrane exhibits high ionic conductivity (8.5×10-4 S cm-1), enabling symmetric and full cells with 10 and 2.5 times longer cycling life compared with that of the cells with pristine LPSCl electrolyte, respectively. The demonstrated strategy is versatile and can be extended to ethylene vinyl acetate copolymer (EVA) that also brings enhanced electrochemical performance. The thin sulfide electrolyte with high interfacial stability potentially facilitates dendrite-free ASSLBs with high energy density.

Synergistic Gas Therapy and Targeted Interventional Ablation With Size-Controllable Arsenic Sulfide (As2S3) Nanoparticles for Effective Elimination of Localized Cancer Pain.

The elimination of localized cancer pain remains a globally neglected challenge. A potential solution lies in combining gas therapy with targeted interventional ablation therapy. In this study, HA-As2S3 nanoparticles with controlled sizes are synthesized using different molecular weights of sodium hyaluronate (HA) as a supramolecular scaffold. Initially, HA co-assembles with arsenic ions (As3+) via coordinate bonds, forming HA-As3+ scaffold intermediates. These intermediates, varying in size, then react with sulfur ions to produce size-controlled HA-As2S3 particles. This approach demonstrates that different molecular weights of HA enable precise control over the particle size of arsenic sulfide, offering a straightforward and environmentally friendly method for synthesizing metal sulfide particles. In an acidic environment, HA-As2S3 nanoparticles release hydrogen sulfide(H2S) gas and As3+. The released As3+ directly damage tumor mitochondria, leading to substantial reactive oxygen species (ROS) production from mitochondria. Concurrently, the H2S gas inhibits the activity of catalase (CAT) and complex IV, preventing the beneficial decomposition of ROS and disrupting electron transfer in the mitochondrial respiratory chain. Consequently, it is found that H2S gas significantly enhances the mitochondrial damage induced by arsenic nanodrugs, effectively killing local tumors and ultimately eliminating cancer pain in mice.

Dysprosium-containing Cobalt Sulfide Nanoparticles as Anticancer Drug Carriers.

Among various materials designed for anticancer drug transport, sulfide nanoparticles are uniquely intriguing owing to their spectral characteristics. Exploration of newer nanoscale copper sulfide particles with dysprosium doping is reported herein. It leads to a change in the physicochemical properties of the sulfide nanoparticles and hence the difference in drug release and cytotoxicity. We intend to purport the suitably engineered cobalt sulfide and dysprosium-doped cobalt sulfide nanoparticles that are magnetic and NIR-absorbing, as drug delivery vehicles. The drug loading and release are based on the supramolecular drug complex formation on the surface of the nanoparticles. The nanomaterials are synthesized employing hydrothermal procedures, coated with a biocompatible poly-β-cyclodextrin, and characterized using the methods of diffractometry, microscopy, spectroscopy, thermogravimetry and magnetometry. The sustained drug release is investigated in vitro. 5-Fluorouracil is loaded in the nanocarriers. The empty and 5-fluorouracil-loaded nanocarriers are screened for their anti-breast cancer activity in vitro on MCF-7 cells. The size of the nanoparticles is below 10 nm. They show soft ferromagnetic characteristics. Further, they show broad NIR absorption bands extending up to 1200 nm, with the dysprosium-doped material displaying greater absorbance. The drug 5-fluorouracil is encapsulated in the nanocarriers and released sustainably, with the expulsion duration extending over 10 days. The IC50 of the blank and the drug-loaded cobalt sulfide are 16.24 ± 3.6 and 12.2 ± 2.6 μg mL-1, respectively. For the drug-loaded, dysprosium-doped nanocarrier, the IC50 value is 9.7 ± 0.3 μg mL-1. The ultrasmall nanoparticles possess a size suitable for drug delivery and are dispersed well in the aqueous medium. The release of the loaded 5-fluorouracil is slow and sustained. The anticancer activity of the drug-loaded nanocarrier shows an increase in efficacy, and the cytotoxicity is appreciable due to the controlled release. The nanocarriers show multi-functional characteristics, i.e., magnetic and NIR-absorbing, and are promising drug delivery agents.

Endocytic pathways and metabolic fate of colloidal bismuth subcitrate in human renal cells

Bismuth compounds, particularly colloidal bismuth subcitrate (CBS), have been widely used in the treatment of gastrointestinal diseases. However, overdose of CBS has been linked to cases of acute renal failure, primarily due to the intracellular accumulation of bismuth in the kidney. To date, the detailed mechanisms of CBS internalization and its metabolic fate remain unclear. In this study, CBS was characterized as a type of nano-object using transmission electron microscopy and dynamic light scattering. Renal cells internalized CBS primarily via clathrin-mediated endocytosis in an active transport manner. Gene knockdown techniques revealed that CBS binds to the transferrin receptor likely through complexing with transferrin before cellular uptake. Once internalized, CBS was sorted into early endosomes, late endosomes, and lysosomes, mediated by microtubules and the Golgi apparatus. Additionally, differentially expressed genes analysis revealed that CBS endocytosis stimulated oxidative stress, significantly affecting the metabolism of glutathione and cysteine within cells. This led to the formation of black bismuth sulfide particles as a result of CBS conjugating with intracellular glutathione. These findings provide crucial insights into the cellular mechanisms underlying excessive CBS exposure, which is essential for understanding and potentially mitigating the risks associated with the use of bismuth compounds in medical treatments.

Enhancement the performance of MAPbI3 perovskite solar cells via germanium sulfide doping

In this study, we successfully doped Germanium sulfide (GeS) particles in methylammonium lead triiodide (CH3NH3PbI3) films to create highly efficient inverted perovskite solar cells (PSC). Various characterization methodologies were employed to examine the impact of GeS on the morphological, structural, and compositional properties of the CH3NH3PbI3 perovskite. The X-ray diffraction and Raman spectroscopy analyses of the synthesized products demonstrated that the crystallinity was enhanced, and tetragonal perovskite structures were generated without any impurities when GeS was used at a high concentration. The surface morphology results indicated that the CH3NH3PbI3 perovskite possessed thin coatings with compact, uniform, and smooth surfaces, with large grain size. The production of a high-quality CH3NH3PbI3 film from the CH3NH3PbI3: GeS phase results in improved carrier lifetime, decreased charge-trap density, and nonradiative recombination of the perovskite films. Band gap was observed to be correlated with grain size and crystallinity, which was accompanied by an increase in GeS concentration. We attained a maximum conversion efficiency of 17.46 % by fabricating solar cells with the following structure: soda-lime glass FTO/TiO2/CH3NH3PbI3: GeS/spiro-oMeTAD/Au. Based on our findings, we believe that the doping of GeS is a promising method for improving the properties of perovskite solar cells that are based on CH3NH3PbI3 thin films.

Manipulating Hardness to Construct Favorable Electrode Microstructures for All‐Solid‐State Batteries

AbstractAll‐solid‐state batteries hold great promise for achieving high energy densities. Fabrication of solid‐state electrodes involves cold compaction of the active material—typically an oxide—with a sulfide electrolyte, during which the softer sulfide particles deform and enwrap the harder oxide particles to afford an “active material‐in‐electrolyte” microstructure where the electrolyte forms a continuous ion‐conducting network. This mechanism however does not apply to emerging active materials that promise even higher energy densities like organic and sulfur‐based compounds. These materials are softer than sulfides and form unfavorable “electrolyte‐in‐active material” microstructures where ionic conduction is interrupted. Improvement of these electrodes is challenging in the absence of strategies to overcome the intrinsic material hardnesses. Here, it is demonstrated how the relative hardness difference can be reversed by simultaneously “softening” a sulfide electrolyte Li6PS5Cl by solvent treatment and “hardening” an organic material pyrene‐4,5,9,10‐tetraone (PTO) through partial lithiation. The lithiated PTO ends up harder than the treated Li6PS5Cl, thus forming the favorable “active material‐in‐electrolyte” microstructure. Cell performance improved as a result, including a 91% increase in material utilization compared with electrodes with unfavorable microstructures, as well as enhanced discharge−charge rates and cycling stability. Such a hardness manipulation strategy has broad applications in solid‐state devices and energy storage.

EPR STUDY OF THE EFFECT OF γ-IRRADIATION ON POLYPROPYLENE/(CdS+ZnS) COMPOSITES

A composite materials with various fillers prepared by adding cadmium sulfide (CdS) and zinc sulfide (ZnS) particles to a polypropylene (PP) matrix and irradiated with different doses of γ-rays were studied by the electron paramagnetic resonance method (EPR). The EPR spectra were investigated, and the nature of the free radicals generated from irradiation was identified. It has been shown that the concentration of radicals in the composites is much lower than in pure PP. The presence of the filler counteracts the effect of γ-rays on the formation of radicals. This result shows that the radiation resistance of the composites is higher.

Effect of peening with fine iron-sulfide particles on the rotating bending fatigue properties of low alloy steel and formation of iron-sulfide layer

Low alloy steels were subjected to peening with fine iron sulfide particles (FeS-peening) under ambient conditions to transfer a layer of such particles, which can improve seizure resistance and sliding properties, and thus enhance the fatigue characteristics of the steel. This process was performed without the use of aqueous Na2S2O3 and the specimens were assessed using electron probe microanalysis and rotating bending fatigue tests. Treated specimens exhibited higher fatigue limits as a result of high degree of compressive residual stress generated on the steel surface. The effects of residual stress on the fatigue limit were quantitatively investigated using a modified Goodman diagram. Sample cross-sections were observed using electron backscattered diffraction, which confirmed that FeS-peening formed fine surface grains. Grain refinement was determined to be at least partly responsible for the improved fatigue properties of the steel following FeS-peening.

Growth behavior of heavy metal sulfide particles: A comparison between gas-liquid and liquid-liquid sulfidation

Sulfide precipitation is an effective method for treating acidic heavy metal wastewater. However, the process often generates tiny particles with poor settling performance. The factors and mechanisms influencing particle size and settling performance remain unclear. In this study, the growth behavior of CuS particles generated by two sulfide precipitation methods, gas-liquid and liquid-liquid sulfidation, was investigated. The effects of acidity, sulfur-to-copper molar ratio, and temperature on particle size were analyzed. The results showed that increasing the temperature had an adverse effect on CuS particle growth. Additionally, we found that acidity and sulfur-to-copper molar ratio had a more significant impact on particle growth in the liquid-liquid sulfidation system than in the gas-liquid sulfidation system. Based on supersaturation calculations and XPS analysis, it is found that particle growth in gas-liquid sulfidation systems is mainly influenced by supersaturation, while particle growth in liquid-liquid sulfidation systems is mainly affected by surface charge. This study provides valuable insights into the factors that influence particle growth in sulfide precipitation and can inform the development of strategies to improve the effective precipitation of sulfide nanoparticles in acidic wastewater.

Preparation of photothermal alginate/chitosan derivative/CuS@polydopamine composite fibers and application in desalination

A polyelectrolyte system consisting of sodium alginate (SA) and quaternary ammonium chitosan (QAC) blended with polydopamine-coated copper sulfide particles (CuS@PDA) was chosen to investigate the function of CuS@PDA in the uniform binary blending of anionic and cationic polyelectrolytes in detail. A smart composite fiber SA/QAC/CuS@PDA was prepared via a dry-wet spinning technique. With the addition of CuS@PDA (about 4.3 % in fiber), the as-prepared SA/QAC/CuS@PDA-0.50 fibers (SQCuS@P-0.50 SCFs) showed notably enhanced intensity 359.2 MPa, excellent moisture response, and photothermal conversion performance, with the temperature increasing from 25.9 to 80.7 °C as irradiated under a 980 nm infrared lamp at distance 20 cm away for 120 s. The photothermal performance was maintained after 6 lighting on-and-off cycles. The tensile strength decreased ~23.8 % after 4 cycles, then remained fixed. The diameter increases to ~480 % in wet state but decreases to the original size in dry state for 10 cycles. When the fabric with 90 wt% SQCuS@P-0.50 SCFs was used as a water evaporator, the water evaporation rate and efficiency were 1.68 kg·m−2·h−1 and 102 % under 1 sun irradiation. This work provides a simple and ecofriendly strategy for fabricating photothermal fabrics by designing and preparing composite fibers.

Explore Ultrasonic-Induced Mechanoluminescent Solutions towards Realising Remote Structural Health Monitoring.

Ultrasonic guided waves, which are often generated and detected by piezoelectric transducers, are well established to monitor engineering structures. Wireless solutions are sought to eliminate cumbersome wire installation. This work proposes a method for remote ultrasonic-based structural health monitoring (SHM) using mechanoluminescence (ML). Propagating guided waves transmitted by a piezoelectric transducer attached to a structure induce elastic deformation that can be captured by elastico-ML. An ML coating composed of copper-doped zinc sulfide (ZnS:Cu) particles embedded in PVDF on a thin aluminium plate can be used to achieve the elastico-ML for the remote sensing of propagating guided waves. The simulation and experimental results indicated that a very high voltage would be required to reach the threshold pressure applied to the ML particles, which is about 1.5 MPa for ZnS particles. The high voltage was estimated to be 214 Vpp for surface waves and 750 Vpp for Lamb waves for the studied configuration. Several possible technical solutions are suggested for achieving ultrasonic-induced ML for future remote SHM systems.

Copper Is Accumulated as Copper Sulfide Particles, and Not Bound to Glutathione, Phytochelatins or Metallothioneins, in the Marine Alga Ulva compressa (Chlorophyta).

To analyze the mechanism of copper accumulation in the marine alga Ulva compressa, it was cultivated with 10 μM of copper, with 10 μM of copper and increasing concentrations of a sulfide donor (NaHS) for 0 to 7 days, and with 10 μM of copper and a concentration of the sulfide acceptor (hypotaurine) for 5 days. The level of intracellular copper was determined as well as the level of glutathione (GSH) and phytochelatins (PCs) and the expression of metallothioneins (UcMTs). The level of intracellular copper in the algae treated with copper increased at day 1, slightly increased until day 5 and remained unchanged until day 7. The level of copper in the algae cultivated with copper and 100 or 200 μM of NaHS continuously increased until day 7 and the copper level was higher in the algae cultivated with 200 μM of NaHS compared to 100 μM of NaHS. In contrast, the level of intracellular copper decreased in the algae treated with copper and hypotaurine. The level of intracellular copper did not correlate with the level of GSH or with the expression of UcMTs, and PCs were not detected in response to copper, or copper and NaHS. Algae treated with copper and with copper and 200 μM of NaHS for 5 days were visualized by TEM and the elemental composition of electrondense particles was analyzed by EDXS. The algae treated with copper showed electrondense particles containing copper and sulfur, but not nitrogen, and they were mainly located in the chloroplast, but also in the cytoplasm. The algae treated with copper and NaHS showed a higher level of electrondense particles containing copper and sulfur, but not nitrogen, and they were located in the chloroplast, and in the cytoplasm. Thus, copper is accumulated as copper sulfide insoluble particles, and not bound to GSH, PCs or UcMTs, in the marine alga U. compressa.