Polarization Method Research Articles

Comparison of dodecyl trimethyl ammonium bromide (DTAB) and cetylpyridinium chloride (CPC) as corrosion inhibitors for mild steel in sulphuric acid solution

Two essential cationic surfactants, dodecyl trimethyl ammonium bromide (DTAB) and cetyl pyridinium chloride (CPC) with differences in the alkyl chain, were investigated as corrosion inhibitors on mild steel (MS) in 0.5 M H2SO4 with weight loss (WL) and the potentiodynamic polarization (PDP) method. Three different temperatures were used to maintain the reported sample solutions (298.15, 308.15, and 318.15 K) for concentrations ranging below, above, and at the optimum critical micelle concentration (CMC) of the cationic surfactants. Results show that 0.5 M DTAB having ammonium group gave higher inhibition efficiency than 0.5 M CPC having pyridinium group by PDP method. The inhibition efficiencies were determined as 98.6% for 0.5 M DTAB and 89.38% for 0.5 M CPC after 24 h immersion at 298.15 K. The extreme inhibition efficiency depends on the chain length and decreases with an increase in temperature as well as increases with the addition of concentration of cationic surfactants. Around CMC, both surfactants CPC and DTAB showed the highest inhibition efficiency which follows the isotherm of Langmuir adsorption and illustrates a mixed type of corrosion inhibitors with the predominance of cathodic reactions. Additionally, the proposed mechanisms of inhibitors showing both physical and chemical adsorption confirmed by the free energy of adsorption (-ΔGads0) for DTAB were >28–34.5 kJ/mol and for CPC were >31.07–42.91 kJ/mol.

Mechanical, morphological, and corrosion features of Ni–Cr oxide nanocomposite coating deposited on SS304 by EPD

AbstractCeramic composites are suitable materials to improve the surface characteristics of steel. Therefore, in this research, Ni–Cr oxide nanocomposite was coated on 304 stainless steel (SS304) by the electrophoretic approach. The effect of chemical composition and coating parameters (time and voltage) was investigated on morphology, corrosion, microhardness, and wear behavior. The nanocomposites were successfully synthesized in three different compositions (Ni–Cr oxides of 70–30, 60–40, and 50–50). The products were coated on the SS304 in 1, 2, and 3 min and 90, 110, and 130 V. Fourier‐transform infrared spectroscopy, X‐ray diffraction, transmission electron microscope, and field emission scanning electron microscopy analyses were employed to investigate the characteristics of the synthesized powder and resulting coatings. The hardness, wear properties, and corrosion resistance of the coating were studied by microhardness, ball‐on‐disk, electrochemical impedance spectroscopy, and polarization methods. The coatings deposited at 1 min and 110 V were sound and free of microcracks. The wear resistance increased by increasing Cr%, so the 50–50 coating showed the best wear resistance with a friction coefficient of .763 and wear mass of 1.6 mg. However, the coating 70–30 presented the highest microhardness of 180.28 Hv. The coating 60–40 had the best corrosion resistance with a corrosion current density of 5.92 µA/cm2. The corrosion resistance improved for thicker coatings.

Investigation of the Electrochemical Corrosion Property of 2xxx Series Cast Aluminium Alloy in 0.3 M, 0.6 M NaCl, and Seawater Environments

The electrochemical corrosion activities of 2xxx series Al alloys were investigated in NaCl of 0.3 M, and 0.6 M concentrations and seawater environments. Both Tafel polarization and electrochemical impedance spectroscopy (EIS) methods were followed to analyze the corrosion behavior. These results implied that corrosive attack is more aggressive in sodium chloride solution compared to seawater, as additional elements present in seawater are involved in forming various protective layers. Again, a higher concentration of NaCl solution damaged the alloy surface more drastically. The open circuit potential moved towards the nobler direction in the case of seawater environment, and 0.3 M solution for NaCl. The corrosion rate and corrosion current showed higher values in NaCl solution than in seawater. The surface morphologies of the alloys were characterized not only with an optical microscope but with a scanning electron microscope also. The scratch marks from polishing were removed after corrosion. Extensive damage to the surface was found in the NaCl environment, where 0.6 M solution created the most damage, which is evident by both optical and scanning electron micrography. A higher level of pitting corrosion occurred in NaCl than in seawater, identified by SEM images.

Technical note: A comparison of methods for estimating coccolith mass

Abstract. The fossil record of coccolithophores dates back approximately 225 million years, and the production of their calcite platelets (coccoliths) contributes to the global carbon cycle over short and geological timescales. Variations in coccolithophore parameters (e.g. community composition, morphology, size and coccolith mass) are a key factor for ocean biogeochemical dynamics (e.g. biological carbon pump) and have been used as a palaeoproxy to understand past oceanographic conditions. Coccolith mass has been frequently estimated with different methods with electron microscopy being the most applied. Here, we compared the electron microscopy (EM) method with the Coulter multisizer (CM) (i.e. electric field disturbance) and bidirectional circular polarization (BCP) methods to estimate coccolith masses (pg CaCO3) in controlled laboratory experiments with two ecotypes of Emiliania huxleyi. Average coccolith mass estimates were in good agreement with literature data. However, mass estimates from the CM were slightly overestimated compared to EM and BCP estimates, and a correction factor (cf=0.8) is suggested to compensate for this discrepancy. The relative change in coccolith mass triggered by morphotype-specific structures and environmental parameters (i.e. seawater carbonate chemistry) was suitably captured by each of the three techniques.

Ti3C2Tx/PANI/CoNi as a ternary composite material unveiling excellent microwave absorption performance

Ti3C2Tx MXene material exhibits exceptional dielectric properties and a distinct layered structure, making it a noteworthy microwave absorbing material. However, its microwave absorption performance is limited due to poor impedance matching and a single loss mechanism. To address these issues, this work develops a solvothermal method to introduce the magnetic component CoNi alloy and generate organic polymer PANI through in-situ polymerization, resulting in the preparation of Ti3C2Tx/PANI/CoNi ternary composites that significantly improve impedance matching and microwave absorption performance. The microwave absorption properties of the binary and ternary composites are compared, and the superior performance of the ternary composites is emphasized. Among the ternary composites, M-P-CN 3:1:8 exhibited an excellent microwave absorption performance, demonstrating a minimum RL value of −55.48 dB and an effective absorption bandwidth of 5.1 GHz at a thickness of 2.0 mm. The synergistic effect of multiple loss mechanisms, multilayer structures, and multiple interfacial polarization methods further contribute to the enhanced microwave absorption performance of ternary composites. This study provides a straightforward method for synthesizing and designing multi-component composite absorbing materials based on MXene.

Study on the effect of different high-voltage electric field polarization process parameters on the vitality of dried chili pepper seeds

To study the effect of different high-voltage electric field polarisation treatment process parameters on the viability of seeds of dried chili peppers. In this study, a high-voltage electrostatic polarisation treatment system was constructed to carry out experiments on the effects of different high-voltage electric field polarisation treatment process parameters on the viability of dried chili seeds. Conduct one-way tests to determine the preferred polarisation method and the preferred interval for output voltage and polarisation time. Two-factor, five-level central combination test with output voltage and polarization time as test factors and seed conductivity as a response indicator. Determining the better combination of parameters for output voltage and polarization time; Conducting seed germination trials to validate the effectiveness of the polarisation process. The results of the one-way test showed that: Negative-voltage polarisation was more effective than positive-voltage polarisation and alternating positive–negative-voltage polarisation in promoting seed vigor, with a better output voltage in the range of 10–14 kV, and a better polarisation time in the range of 20–40 s; The results of orthogonal tests showed that: Under the condition of negative voltage polarisation treatment, the output voltage of 12.08 kV and polarisation time of 30.32 s was the better parameter combination, at which the seed conductivity was minimum 159.87 uS/(cm g). Analyzing the function of cell membrane selective semi-permeability by seed conductivity change and revealing the mechanism of seed viability enhancement by high voltage electric field polarisation treatment; In the seed germination test, compared with the control group, seed germination potential increased by 9.09%, germination rate increased by 20.45%, germination index increased by 3.49, and vigor index increased by 41.66 under high-voltage electrostatic polarisation treatment, and all vigor indexes were significantly improved. The results of this study can provide a basis for the selection of processes and parameters for subsequent high-voltage electric field polarisation treatment of crop seeds.

Embeddable Chloride Sensor for Monitoring Chloride Penetration into Cement Mortar.

A composite solid chloride sensor consisting of two single sensors, i.e., Ag/AgCl working electrode and Mn/MnO2 reference electrode, was developed. The Ag/AgCl electrode was prepared by the anodic polarization method, while the Mn/MnO2 reference electrode was prepared using the powder compaction technique. Then, the electrochemical performances such as stability, reproducibility, and sensitivity of the composite and single sensors were investigated in a saturated Ca(OH)2 solution and mortar specimen. A current density of 0.5 mA/cm2 and polarization time of 2.5 h were the optimal preparation parameters of the Ag/AgCl selective electrode. The Ag/AgCl selective electrode showed a linear potential response with the logarithm of chloride ion content in solution and had good stability, reproducibility, and anti-polarization performances. In addition, the Mn/MnO2 electrode exhibited potential stability after being activated in an alkaline solution for 60 days. The composite sensor demonstrated exceptional sensitivity to the Cl- content, boasting a slope of approximately 51.1 mV/decade, and showcased excellent stability in both solution and mortar specimens. In every measurement, the time needed for the potential of a composite sensor to become stable was less than 30 s. The sensor enables non-destructive in situ monitoring of the chloride ion content in cement mortar, thus realizing early warning of deterioration of reinforcement and guaranteeing long service life of the structure.

Monitoring of copper adsorption on biochar using spectral induced polarization method

Copper contaminant generated from mining and industrial smelting poses potential risks to human health. Biochar, as a low-energy and cost-effective biomaterial, holds value in Cu remediation. Spectral Induced Polarization (SIP) technique is employed in this study to monitor the Cu remediation processes of by biochar in column experiments. Cation exchange at low Cu2+ concentrations and surface complexation at high Cu2+ concentrations are identified as the major mechanisms for copper retention on biochar. The normalized chargeability (mn) from SIP signals linearly decreased (R2 = 0.776) with copper retention under 60 mg/L Cu influent; while mn linearly increases (R2 = 0.907, 0.852) under high 300 and 700 mg/L Cu influents. The characteristic polarizing unit sizes (primarily the pores adsorbing Cu2+) calculated from Schwartz equation match well with experimental results by mercury intrusion porosimetry (MIP). It is revealed that Cu2+ was driven to small pores (∼3 μm) given high concentration gradient (influent Cu2+ concentration of 700 mg/L). Comparing to activated carbon, biochar is identified as an ideal adsorbent for Cu remediation, given its high adsorption capacity, cost-effectiveness, carbon-sink ability, and high sensitivity to SIP responses – the latter facilitates its performance assessment.

CORROSION EVALUATION OF LPBF-MANUFACTURED DUPLEX STAINLESS STEEL

In this study, the effect of as built and heat-treated additively manufactured 2507 super duplex stainless steel (SDSS) on electrochemical corrosion performance was examined. The corrosion was studied by Tafel polarization and electrochemical impedance spectroscopy (EIS) methods in a 3.5% NaCl solution. For this purpose, the as-built and heat-treated printed samples (solution annealed and stress-relieved) were examined by LOM/SEM and X-ray diffraction to evaluate the phase changes of steel at different processing stages. The correlation between corrosion resistance, structure, and heat treatment was assessed. As a result of the very fast cooling rate of the LPBF process, SDSS reveals ferrite as the major phase in the printed samples. To enhance the corrosion resistance of LPBF-produced duplex stainless steel, it's crucial to balance its two-phase structure and minimize residual stresses. The ferrite grains are elongated in the build direction, with some austenite precipitation along the grain boundaries or as Widmanstatten laths. The stress-relieved and as-printed SDSS exhibits reduced corrosion characteristics by around 20% compared to the solution-annealed SDSS, according to anodic polarization curves. Based on EIS results, the solution-annealed SDSS revealed an almost double increase in corrosion resistance (based on charge transfer resistance values) compared to the as-printed and stress-relieved conditions.

Searching for exotic spin-dependent interactions with diamond-based vector magnetometer

We propose a new method to search for exotic spin-spin interactions between electrons and nucleons using a diamond-based vector magnetometer. The vector magnetometer can be constructed from ensembles of nitrogen-vacancy centers along different axes in a diamond. The N14 nuclear spins of nitrogen-vacancy centers in the same diamond can be polarized through the dynamic nuclear polarization method to serve as spin sources. With the vector magnetometer, the sought-after exotic interactions can be distinguished from the magnetic dipole-dipole interaction. For the axion-mediated interaction VPP, new upper bounds of the coupling |gPegPN| are expected within the force range from 10 nm to 100 μm. For the Z′-mediated interaction VAA, new upper bounds of the coupling |gAegAN| are expected within the force range from 10 nm to 1 cm. The new upper bounds for VPP and VAA are both expected to be more than 5 orders of magnitude more stringent than existing constraints at the force range of 1 μm with the total measurement time of 1 day. Published by the American Physical Society 2024

The Inhibition Action of Some Brij-Type Nonionic Surfactants on the Corrosion of OLC 45 in Various Aggressive Environments.

The corrosion protection property of three Brij-type surfactants, namely, Brij 35, Brij 56 and Brij 58P, was considered on OLC 45 carbon steel in a 0.5 M H2SO4 medium. The efficacy for these organic compounds was examined using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods, scanning electron microscopy (SEM) procedures, and Fourier transform infrared (FT-IR) spectroscopy. We hypothesized that these surfactants hinder the corrosion for OLC 45 samples through a protecting mechanism owing to the adsorption of organic molecules that form an inhibitive film or through the formation of complex oxides. These surfactants exhibited an appreciable protective effect against OLC 45 corrosion, operating as mixed inhibitors, as could be demonstrated by their influence on the electrochemical characteristics of the metallic substrates. The adsorption of surfactants over the substrates zone conformed to the representation of the Langmuir isotherm. The effect of temperature on the electrochemical comportment of the OLC 45 specimens in H2SO4 without and with Brij at 800 ppm was examined in the temperature interval of 293 to 333 K. The negative estimate of thermodynamic attributed as Gibbs free energy of adsorption presented the spontaneity of the adsorption activity. The investigation with FT-IR and SEM established the adsorption of Brij and the constitution of the corrosive components on the OLC 45 surface. Electrochemical determinations of these surfactants indicated its anticorrosion inhibition performance and the highest inhibition of 96% was reached when the Brij 35 concentration was at 800 or 1000 ppm, while for Brij 56 and Brij 58P, the highest inhibition was obtained when their concentrations were 500, 800, or 1000 ppm.

Green Ostrich fat waste extracts as a novel potential inhibitor to sustainable corrosion of steel in acidic environments: Electrochemical and DFT evaluation

The shift from traditional chemical corrosion inhibitors to green alternatives, focusing on plant extracts (GCIs), addresses environmental concerns in line with sustainable development goals. An innovative approach explores animal-derived extracts for eco-friendly corrosion inhibition, addressing environmental issues associated with conventional chemical inhibitors. Ostrich Oil, renowned for its nutritional, cosmetic, and pharmaceutical properties, is examined as a potential green corrosion inhibitor for C38 steel in 1 M hydrochloric. Extracted and characterized through GC-FID, Ostrich Oil exhibits corrosion protection analyzed via impedance spectroscopy, potentiodynamic polarization, and gravimetric methods. Complementary SEM and metallurgical microscopy with EDS offer surface insights. DFT and MD simulations explore the relationship between electronic properties and inhibition efficiency. Results show Ostrich Oil's significant corrosion inhibition (up to 94%), attributed to chemical adsorption of fatty compounds. The corrosion mechanism is influenced by Oil extract adsorption, increasing double electrochemical layer resistance. Gas chromatography identifies main compounds, and quantum chemical calculations highlight its reactivity. This research underscores the potential of animal-derived extracts, exemplified by Ostrich Oil, as effective and environmentally friendly corrosion inhibitors, contributing to sustainable corrosion protection practices.

Induced Polarization of Clayey Rocks and Soils: Non‐Linear Complex Conductivity Models

AbstractThe past decades have witnessed the increased applications of induced polarization (IP) method in the critical zone studies with ubiquitous clay minerals. Although IP outperforms traditional electrical and electromagnetic methods through its unique ability to measure quadrature conductivity, the nonlinearity that quadrature conductivity behaves with salinities and frequencies greatly tortures IP practitioners, as (a) salinity‐dependency makes the quadrature conductivity a varyingly unstable parameter to quantitatively estimate hydraulic properties and clay content; (b) frequency‐dependent Cole‐Cole and Debye/Warburg decomposition models, although mathematically sound, physically mingle the properties of pore water and clay minerals and are empirical in nature. From basic principles, we demonstrate that quadrature conductivity remains a hybrid property involving both clay and water, and develop relevant models to distinguish them. Our models are validated by theories, experiments, simulations, and comparisons, all of which proclaim considerable advantages over previous models and offer the prospect of quantitative applications.

In Situ Spin Polarization Measurement Method and Identification of Optimal Spin Polarization Range in Atomic Magnetometer

AbstractIn this study, an in situ measurement method of spin polarization in single‐beam atomic magnetometer is presented. Modeling magnetic linewidth by incorporating nonlinear attenuation along the propagation direction of light and employing the output response equation of magnetometers at zero‐field resonance. Utilizing the model for fitting to extract relaxation rate information, the photon absorption cross‐sections at three temperatures are estimated to be , , and , respectively. Further, the spin polarization curves are obtained by introducing the spin polarization equations. Given the diminishing marginal utility resulting from the enhancement of performance through increased spin polarization, long‐term sensitivity is employed to determine optimal spin polarization range. The optimal long‐term sensitivity for four displayed states is (@31.5Hz), while the ultimate minimum sensitivity is 10.7 (@31.5Hz). The optimal spin polarization ranges at three temperatures are 78.9%–87.1%, 82.3%–88.5%, and 84.5%–88.4%, respectively. The measurement method applied to single‐beam magnetometer can be easily extended to multi‐axis vector magnetometer. The determination of optimal spin polarization range is of great significance for the performance and stability of the magnetometer system, improving the sensitivity of magnetic field measurement, and ensuring its widespread application in bio‐magnetic measurement.

The investigation of cytotoxic and apoptotic activity of Cl-amidine on the human U-87 MG glioma cell line.

Peptidyl (protein) arginine deiminases (PADs) provide the transformation of peptidyl arginine to peptidyl citrulline in the presence of calcium with posttranslational modification. The dysregulated PAD activity plays an important role on too many diseases including also the cancer. In this study, it has been aimed to determine the potential cytotoxic and apoptotic activity of chlorine-amidine (Cl-amidine) which is a PAD inhibitor and whose effectiveness has been shown in vitro and in vivo studies recently on human glioblastoma cell line Uppsala 87 malignant glioma (U-87 MG) forming an in vitro model for the glioblastoma multiforme (GBM) which is the most aggressive and has the highest mortality among the brain tumors. In the study, the antiproliferative and apoptotic effects of Cl-amidine on GBM cancer model were investigated. The antiproliferative effects of Cl-amidine on U-87 MG cells were determined by 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate method at the 24th and 48th hours. The apoptotic effects were analyzed by Annexin V and Propidium iodide staining, caspase-3 activation, and mitochondrial membrane polarization (5,5', 6,6'-tetrachloro-1,1', 3,3' tetraethyl benzimidazolyl carbocyanine iodide) methods in the flow cytometry. It has been determined that Cl-amidine exhibits notable antiproliferative properties on U-87 MG cell line in a time and concentration-dependent manner, as determined through the 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate assay. Assessment of apoptotic effects via Annexin V and Propidium iodide staining and 5,5', 6,6'-tetrachloro-1,1', 3,3' tetraethyl benzimidazolyl carbocyanine iodide methods has revealed significant efficacy, particularly following a 24-hour exposure period. It has been observed that Cl-amidine induces apoptosis in cells by enhancing mitochondrial depolarization, independently of caspase-3 activation. Furthermore, regarding its impact on healthy cells, it has been demonstrated that Cl-amidine shows lower cytotoxic effects when compared to carmustine, an important therapeutic agent for glioblastoma. The findings of this study have shown that Cl-amidine exhibits significant potential as an anticancer agent in the treatment of GBM. This conclusion is based on its noteworthy antiproliferative and apoptotic effects observed in U-87 MG cells, as well as its reduced cytotoxicity toward healthy cells in comparison to existing treatments. We propose that the antineoplastic properties of Cl-amidine should be further investigated through a broader spectrum of cancer cell types. Moreover, we believe that investigating the synergistic interactions of Cl-amidine with single or combination therapies holds promise for the discovery of novel anticancer agents.

High-Temperature Protonic Conduction in La2NiO4+ δ-Based Ruddlesden-Popper Type Oxides: Correlation with Concentration of Interstitial Oxide Ions.

Oxygen-excess La2NiO4+ δ (LNO) conducts oxide ions, electron holes, and hydroxide ions simultaneously on exposing to wet oxygen, exhibiting the potential as a cathode material in protonic ceramic fuel cells. Since the incorporation of protons in oxygen-excess LNO is via the hydration reaction assisted by interstitial oxide ions, in this work, the concentration of interstitial oxide ions is reduced and increased by substituting Ni with Cu and Co, respectively. A higher concentration of interstitial oxide ions leads to a high proton concentration, indicating the predominant role of interstitial oxide ions in the hydration reaction, different from that in the oxygen-deficient oxides, where protons are introduced by dissociative absorption of water molecules by oxygen vacancies. The theoretical calculation indicates that protons in Co-doped LNO prefer to locate between the interstitial oxide ions and unshared apical oxide ions. A trapping effect is found between protons and the oxide ions near Cu, leading to decreased proton mobility. Protonic conductivity at 400-575 °C is then directly measured by a Hebb-Wagner direct current polarization method with La0.99Ca0.01NbO4- δ as the blocking electrode, enabling the observation that Co-doped LNO has the highest protonic conductivity among the samples studied in this work.

DETEKSI ZONA MINERALISASI EMAS DI GUNUNG GUPIT, MAGELANG MENGGUNAKAN METODE INDUCED POLARIZATION

Mount Gupit is an area with gold mineralization potential which is part of the Menoreh Mountains, in the Magelang area. Mineralization potential mapping was carried out using geophysics, namely the Induced Polarization method. Induced Polarization Method measurements were carried out in 5 trajectories in a relatively west to east direction and with varying path lengths. The configuration used is a dipole-dipole configuration with a: 10 meters and n: 1-6. Interpretation is carried out on the results of the Resistivity and Chargeability data inversion. The inversion results show a resistivity range from 2 to 400 Ohm-m. Resistivity values are divided into three criteria, namely low with a value of less than 10 Ohm-m as clay rock, medium with a range of (10-75) Ohm-m as pyroclastic breccia and high with a value greater than 75 Ohm-m as intrusion or chunks of andesite. The inversion results show that the chargeability value varies from 2 to 80 ms. This value is divided into three criteria, namely low (<10 ms), medium (10 to 35) ms and high (>35 ms). Low chargeability values are interpreted as zones that are not mineralized so that there are no metal minerals. The mineralized zone is being interpreted from a moderate chargeability value. Meanwhile, a high chargeability value is interpreted as a zone that is strongly mineralized and contains significant metallic minerals. The existence of a mineralized zone stretches from track 2 to track 5 to the north, while the zone has disappeared or been exhausted in track 1 to the south of the research area.

Polarizable Nonvolatile Ferroelectric Gating in Monolayer MoS2 Phototransistors.

Given the requirements for power and dimension scaling, modulating channel transport properties using high gate bias is unfavorable due to the introduction of severe leakages and large power dissipation. Hence, this work presents an ultrathin phototransistor with chemical-vapor-deposition-grown monolayer MoS2 as the channel and a 10.2 nm thick Al:HfO2 ferroelectric film as the dielectric. The proposed device is meticulously modulated utilizing an Al:HfO2 nanofilm, which passivates traps and suppresses charge Coulomb scattering with Al doping, efficiently improving carrier transport and inhibiting leakage current. Furthermore, a bipolar pulses excitable polarization method is developed to induce a nonvolatile electrostatic field. The MoS2 channel is fully depleted by the switchable and stable floating gate originating from remanent polarization, leading to a high detectivity of 2.05 × 1011 Jones per nanometer of gating layer (Jones nm-1) and photocurrent on/off ratio >104 nm-1, which are superior to the state-of-the-art phototransistors based on two-dimensional (2D) materials and ferroelectrics. The proposed polarizable nonvolatile ferroelectric gating in a monolayer MoS2 phototransistor promises a potential route toward ultrasensitive photodetectors with low power consumption that boast of high levels of integration.

Surface Modification of Diatomite-Based Micro-Arc Coatings for Magnesium Implants Using a Low-Energy High-Current Electron Beam Processing Technique

The present study showcases a novel effective technique for the surface modification of micro-arc diatomite coatings using low-energy, high-current electron beams (LEHCEBs). A variety of methods such as scanning electron microscopy, energy-dispersive X-ray spectroscopy, the X-ray diffraction method, scratch testing, the potentiodynamic polarization method, immersion testing in SBF, and flow cytometry have been used to study the coatings. During processing, the electron beams’ energy density ranged between 2.5–7.5 J/cm2. After the LEHCEB treatment, the surface morphology of the coatings changed completely. The corrosion resistance of the LEHCEB-treated coated samples increased significantly, as evidenced by the decrease in corrosion current to 4.6 × 10−10 A·cm−2 and the increase in polarization resistance to 1.4 × 108 Ω·cm2. The electron beam treatment also increased the adhesion strength of the coatings to the magnesium substrate by 1.8–2.5 times compared to untreated coatings. Additionally, biological studies have shown the high viability of the NIH/3T3 cell line after contact with the samples of the coating extracts.

The Berkovići (BIH) ML = 6.0 earthquake sequence of 22 April 2022 – Seismological and seismotectonic analyses

In the southeast of Bosnia and Herzegovina, the Berkovići earthquake sequence started with the mainshock on 22 April 2022 21:07 UTC at focal depth 22 km with magnitude ML = 6.0 (Mw = 5.7). Our preliminary estimation of the mainshock's maximum intensity is VII EMS for Berkovići where 29% of buildings were damaged. We analysed the first nine months of this sequence, 22 April 2022–22 January 2023. The earthquakes were located using a guided grid-search algorithm with source-specific station corrections as a mean of solutions for 54 combinations of velocity models and program control parameters. The analysis of aleatory variation and epistemic uncertainty showed that they are very dependent on the station coverage, especially for focal depth. The event catalogue consists of 7217 earthquakes and can be considered complete for ML ≥ 1.3. Focal depths (15–30 km) are considerably larger than average for the Dinarides, but consistent within the zone of mid-crustal events where the earthquakes occurred. Focal mechanisms were determined with the first-motion polarity method for eight earthquakes: five of them, including the mainshock, were due to reverse faulting on faults striking in the Dinaric direction, with the preferred main fault gently dipping to the northeast. However, three events were due to normal faulting, unexpected for this area. We constructed a regional seismotectonic cross-section to delineate a potential seismogenic source of the mainshock, and it suggests that the mainshock occurred on the NE-dipping blind ramp of the basal thrust of the Dalmatian tectonic unit. Moreover, another NE-dipping and blind ramp of this basal thrust could be responsible for the Ston–Slano 1996 earthquake, located to the SW of the Berkovići mainshock hypocentre at the horizontal distance of c. 35 km.