Search Results (46)

Artisanal fisheries in southern Chile rely heavily on the Patagonian red octopus (Enteroctopus megalocyathus) as a valuable resource, contributing significantly to local economies. This octopus species accounts for 25–40% of Chilean octopus landings. It is a merobenthic species, characterized by a semelparous life cycle and a long brooding period, and it is distributed along the Pacific and Atlantic coasts of the southern tip of South America, inhabiting holes and crevices in rocky substrates. However, this fishery faces critical challenges to both its ecological sustainability and the food safety of octopus products. The primary fishing method, using hooks, poses a risk to reproductive capacity as it can capture brooding females. Food safety concerns arise from microbial contamination during pre- and post-harvest handling, bioaccumulation of toxins from algal blooms, and the presence of heavy metals in the marine environment. While evisceration effectively reduces the risk of consuming toxins and heavy metals, inadequate hygiene practices and insufficient ice usage throughout the production chain represent significant food safety risks. Chilean fishing Law No. 18892/1989 defines artisanal fishing and establishes territorial use rights in fisheries (TURFs) to promote sustainable extraction of benthic resources. Integrating training programs on post-harvest handling, hygiene practices, and food safety measures into the TURFs framework, along with targeted investments in infrastructure and technical assistance, is crucial to ensure the long-term sustainability of the E. megalocyathus fishery, protect consumer health, and maintain the economic viability and environmental sustainability of this vital resource for local communities. Full article

This paper presents numerical studies of the viscous droplet impact on dry and wetted solid walls for spray painting applications, focusing on air entrapment, film structure, and flake (flat pigment) orientation. The results were compared with experimental observations using various high-speed camera arrangements. For paint droplet impact on dry substrates, a dynamic contact angle model was developed and used in numerical simulations. This contact angle model was verified with experimental observations. For the droplet impact on wet surfaces, characteristic crater sizes (diameter and depth) were defined considering also the effect of the film thickness. A strong correlation with the droplet impact Reynolds number was observed. In addition, a user-defined 6DOF (6-degrees-of-freedom) solver was implemented in a CFD program to perform calculations of rigid body motions within the impacting droplet, technically relevant for the resulting effect of flakes in metallic effect paints. The developed models were applied in parameter studies to further clarify the existing dependencies on application and fluid parameters more quantitatively. The simulation results are helpful to understand and to improve painting processes with respect to the final quality parameters. Full article

Metal anodes, such as those based on Ca, Mg, Na and Li, are considered to be one of the keys to the further development of high-energy-density rechargeable batteries. The thickness of these metal anodes directly affects the energy density of the battery. However, the fabrication of thin anodes poses technical challenges which often result in using excessively thick metal anodes in batteries. Here we present, for the first time, a study on the development of a thin Ca battery anode fabricated by electrodeposition. The battery anode with a thickness of approximately 10 µm corresponds to a charge density of 4.0 mAh cm⁻². This study systematically investigates the electrodeposition behavior of Ca using a 1.0 M Ca(BH₄)₂ in THF as the electrolyte. A systematic evaluation of electrodeposition parameters—including substrate pretreatment, current density, hydrodynamics and charge density by area—is conducted. Scanning electron microscopy (SEM) and complementary image analysis provide detailed insights into these parameters. Electrodeposition offers a promising route to achieve a defined battery cell balance with minimal excess of metal at the anode. This will improve overall battery performance and efficiency. The findings contribute to the advancement of fundamental aspects of rechargeable batteries, particularly Ca-based batteries. Full article

Frequency multipliers are essential components in communication systems, and graphene’s exceptional electrical properties make it highly promising for flexible electronics. This paper addresses the technical challenges of multi-frequency multipliers based on graphene field-effect transistors (GFETs) and introduces a novel fabrication method using graphene as the channel material and metals with different work functions as the top gate. By employing Ti and Pd with distinct work functions, we develop a dual-gate GFET device that exhibits stable M-shaped resistance characteristics on a flexible polyethylene naphthalate (PEN) substrate. We demonstrate frequency doubler, tripler, and quadrupler on the flexible substrate. The results show that the GFET-based frequency multiplier offers advantages such as low operating voltage (<1 V), high voltage conversion efficiency (up to 8.4% for tripler and 6% for quadrupler), and high spectral purity (up to 88% for tripler and 76% for quadrupler). The intrinsic maximum operating frequency of the frequency quadrupler reaches 54 GHz. The use of a monolayer graphene channel, dual-metal gate control enabling an M-shaped transfer curve, and flexible characteristics all contribute to its superior performance compared to conventional devices. Full article

A balanced dielectric resonator filtering power divider with isolation performance is proposed. By using the coupling of the ${\mathrm{T}\mathrm{E}}_{111}^{\mathrm{y}}$ modes between three rectangle dielectric resonators, combined with balanced feed structures, the differential-mode filtering and power dividing functions, as well as the common-mode suppression were achieved effectively. Additionally, by technically utilizing the hollow structure of the stacked substrates, isolation resistor structures are introduced at the two output ports to improve the isolation level of the power divider. It can solve the problem of traditional metal-cavity dielectric resonator filter power dividers being unable to add isolation structures due to structural reasons. Compared with the reported dielectric resonator filtering power dividers, the proposed one has the characters of a lower profile and high isolation. For demonstration, one dielectric resonator filtering power divider was fabricated and measured at 11.65 GHz with the profile of 0.66 λ_g and an isolation higher than 15 dB. The simulation results are in good agreement with the measured results. Full article

To achieve the rapid heat dissipation of components in the industrial field, the heat dissipation coating is prepared on the surface, which is conducive to improving the service life of the parts and greatly reducing the industrial costs. In this paper, metallized diamond/Cu composite coatings were fabricated on 1060Al substrate by supersonic laser deposition. The composite coatings were prepared at a nitrogen pressure of 3.0 MPa, a scanning speed of 10 mm/s, and a 1060 nm semiconductor coupled fiber laser with different laser power. The research results show that the laser power affects the interface bonding by affecting the temperature of adiabatic shear instability during particle impact. The metallized diamond forms a good bonding at the interface through the plastic deformation of the Cu matrix. Appropriate parameters ensure that the jet does not affect the subsequent particle deposition and build a good heat transfer bridge to elevate the heat transfer efficiency. The coating prepared at a laser power of 1000 W has the highest thermal diffusion coefficient of 89.3 mm²/s and thermal conductivity of 313.72 W/(m·K), which is 8.92% higher compared to the coating prepared without laser. Experiments with thermal imaging have also demonstrated that the coating at optimal parameter transferred heat faster. Our research provides a technical guidance for rapid preparation of high-quality heat dissipation coatings in industry. Full article

In this study, a MOF-199/Ag@Au SERS sensing structure was successfully synthesized by combining metal–organic frameworks (MOFs) with surface-enhanced Raman scattering (SERS) technology for the efficient detection of dopamine (DA), a biomarker for neurological diseases, in serum. Using electrochemical methods, a copper-based MOF (MOF-199) was synthesized in situ on copper substrates and further deposited with silver nanoparticles (AgNPs). Subsequently, gold nanoshells were encapsulated around these silver cores by in situ chemical deposition. This preparation process is simple, controllable, and inexpensive. Furthermore, a novel Azo reaction-based DA SERS method was proposed to detect 1 pM DA, which represents an improvement in sensitivity by two orders of magnitude compared to previous unlabeled SERS detection methods and by four orders of magnitude compared to another SERS approach proposed in this work. There was an excellent linear relationship (R² = 0.976) between the SERS signal at 1140 cm⁻¹ and the DA concentration (0.001 M~1 pM). The results indicate that the MOF-199/Ag@Au sensor structure can successfully achieve both the qualitative and quantitative detection of DA in serum, thus providing a robust technical basis for the application of SERS technology in the field of clinical neurological disease screening. Full article

Surface-enhanced Raman spectroscopy (SERS) has emerged as a powerful technique for the detection and analysis of biomolecules due to its high sensitivity and selectivity. In recent years, SERS-based sensors have received significant attention for the detection of deoxyribonucleic acid (DNA) molecules, offering promising applications in fields such as medical diagnostics, forensic analysis, and environmental monitoring. This paper provides a concise overview of the principles, advancements, and potential of SERS-based sensors for DNA detection. First, the fundamental principles of SERS are introduced, highlighting its ability to enhance the Raman scattering signal by several orders of magnitude through the interaction between target molecules with metallic nanostructures. Then, the fabrication technologies of SERS substrates tailored for DNA detection are reviewed. The performances of SERS substrates previously reported for DNA detection are compared and analyzed in terms of the limit of detection (LOD) and enhancement factor (EF) in detail, with respect to the technical parameters of Raman spectroscopy (e.g., laser wavelength and power). Additionally, strategies for functionalizing the sensor surfaces with DNA-specific capture probes or aptamers are outlined. The collected data can be of help in selecting and optimizing the most suitable fabrication technology considering nucleotide sensing applications with Raman spectroscopy. Full article

High-definition near-eye display technology has extremely close sight distance, placing a higher demand on the size, performance, and array of light-emitting pixel devices. Based on the excellent photoelectric performance of metal halide perovskite materials, perovskite light-emitting diodes (PeLEDs) have high photoelectric conversion efficiency, adjustable emission spectra, and excellent charge transfer characteristics, demonstrating great prospects as next-generation light sources. Despite their potential, the solubility of perovskite in photoresist presents a hurdle for conventional micro/nano processing techniques, resulting in device sizes typically exceeding 50 μm. This limitation impedes the further downsizing of perovskite-based components. Herein, we propose a plane-structured PeLED device that can achieve microscale light-emitting diodes with a single pixel device size < 2 μm and a luminescence lifetime of approximately 3 s. This is accomplished by fabricating a patterned substrate and regulating ion distribution in the perovskite through self-doping effects to form a PN junction. This breakthrough overcomes the technical challenge of perovskite–photoresist incompatibility, which has hindered the development of perovskite materials in micro/nano optoelectronic devices. The strides made in this study open up promising avenues for the advancement of PeLEDs within the realm of micro/nano optoelectronic devices. Full article

Industrialization has brought many environmental problems since its expansion, including heavy metal contamination in water used for agricultural irrigation. This research uses microbial fuel cell technology to generate bioelectricity and remove arsenic, copper, and iron, using contaminated agricultural water as a substrate and Bacillus marisflavi as a biocatalyst. The results obtained for electrical potential and current were 0.798 V and 3.519 mA, respectively, on the sixth day of operation and the pH value was 6.54 with an EC equal to 198.72 mS/cm, with a removal of 99.08, 56.08, and 91.39% of the concentrations of As, Cu, and Fe, respectively, obtained in 72 h. Likewise, total nitrogen concentrations, organic carbon, loss on ignition, dissolved organic carbon, and chemical oxygen demand were reduced by 69.047, 86.922, 85.378, 88.458, and 90.771%, respectively. At the same time, the PD_MAX shown was 376.20 ± 15.478 mW/cm², with a calculated internal resistance of 42.550 ± 12.353 Ω. This technique presents an essential advance in overcoming existing technical barriers because the engineered microbial fuel cells are accessible and scalable. It will generate important value by naturally reducing toxic metals and electrical energy, producing electric currents in a sustainable and affordable way. Full article

In this study, CoCrMo cuboid samples were deposited on a CuZrCr substrate using laser powder bed fusion (L-PBF) technology to investigate the influence of process parameters and laser remelting strategies on the mechanical properties and interface characteristics of multi-metals. This study found that process parameters and laser scanning strategies had a significant influence on the mechanical properties and interface characteristics. Samples fabricated with an $E_{\mathrm{V}}$ ≤ 20 J/mm³ showed little tensile ductility. As the volumetric energy density ($E_{\mathrm{V}}$) increased to a range between 40 J/mm³ and 100 J/mm³, the samples achieved the desired mechanical properties, with a strong interface combining the alloys. However, an excessive energy density could result in cracks due to thermal stress. Laser remelting significantly improved the interface properties, especially when the $E_{\mathrm{V}}$ was below 40 J/mm³. Variances in the $E_{\mathrm{V}}$ showed little influence on the hardness at the CuZrCr end, while the hardness at the interface and the CoCrMo end showed an increasing and decreasing trend with an increase in the $E_{\mathrm{V}}$, respectively. Interface characterization showed that when the $E_{\mathrm{V}}$ was greater than 43 J/mm³, the main defects in the L-PBF CoCrMo samples were thermal cracks, which gradually changed to pores with a lack of fusion when the $E_{\mathrm{V}}$ decreased. This study provides theoretical and technical support for the manufacturing of multi-metal parts using L-PBF technology. Full article

The work aims to enhance and modify the armature surface in electromagnetic rail launch systems and improve its anti-ablation performance to better resist the impact ablation effects of high-temperature and high-speed arcs during the electromagnetic rail launch process and improve launch reliability. TiC particles are widely selected as metal material reinforcements, with advantages such as high melting points and high hardness. In this paper, the arc impact model of pure aluminum alloy and the arc impact model of TiC particle-reinforced aluminum-matrix composite coating–pure aluminum alloy were constructed based on molecular dynamics simulation. The ablation resistance of the material was evaluated by analyzing the depth of arc impact, the mass loss of the model, the number of gasification atoms, and the surface temperature of the material. The protection mechanism of the modified layer on the substrate was revealed by analyzing the damage degree of the surface and subsurface of the material after arc impact. The results showed that the strengthening mechanism of TiC particle-reinforced aluminum-matrix composites included fine grain strengthening, dispersion strengthening, dislocation strengthening, and so on. Covering TiC particle-reinforced aluminum-matrix composite coating on the surface of aluminum alloy armature is helpful in improving its ablation resistance. The research results can provide a theoretical basis and technical support for the modification design and performance control of electromagnetic rail armature. Full article

In an electromagnetic launch system, the surface of the aluminum alloy armature is subjected to high-temperature ablation, leading to the generation of significant metal vapor and the initiation of high-energy arcs. This damages the armature structure and can result in a launch failure. Enhancing the ablation resistance of the armature surface is crucial for improving launch efficiency. In this study, a model for the surface modification of an aluminum alloy armature was constructed. The impact of the CoCrNiFeAl_x surface-modified material on the resistance to ablation and structural changes of the armature during arc ablation was elucidated through molecular dynamics simulation. Results show that adding a CoCrNiFeAl_x fused cladding layer can effectively enhance the material’s high-temperature resistance. The CoCrNiFeAl_x fused cladding significantly reduces the depth of arc intrusion. The CoCrNiFeAl_x aluminum alloy model exhibits a narrower strain range on the bombarded surface and a more flattened bombardment crater shape. CoCrNiFeAl_x fused cladding helps to reduce damage from substrate bombardment. Comparing simulation results indicates that CoCrNiFeAl_0.25 performs best in high-temperature resistance and impact strength, making it the most preferred choice. This study elucidates the law of high-entropy alloy arc ablation resistance and its micromechanism in armature surface modification. It provides a theoretical basis and technical support for preparing high-entropy alloy–aluminum alloy-modified armatures with superior ablation resistance performance. Full article

The growing demand for sustainable and innovative materials in product design has spurred interest in unconventional resources. Despite this, a gap persists in the effective utilization of paper-based materials, particularly with metallic coatings, for creative applications. This study aims to address this by exploring the technical methods for applying Aluminum (Al) coatings to paper substrates. We developed paper-based aluminum coatings and combined them with corrugated cardboard to create a novel material for product development. Utilizing high-strength specialty paper as the substrate, an orthogonal experiment was conducted to identify key process parameters. Factors such as target–substrate distance, working pressure, current intensity, and coating duration were evaluated for their impact on the properties of the Al film. Our research culminated in the production of high-quality Al-plated corrugated cardboard. Capitalizing on its unique attributes, we employed a design approach that led to the creation of innovative furniture featuring structural forms like folding and insertion. This study not only introduces a new range of Al-plated corrugated cardboard products but also expands the potential applications of paper-based aluminized film in material-based product design. Full article

A few components used in the aerospace and petrochemical industries serve in corrosive environments at high temperatures. Corrosion-resistant metals or unique processes, such as coating and fusion welding, are required to improve the performance of the parts. We have used laser powder bed fusion (LPBF) technology to deposit a 5 mm thick corrosion-resistant CoCrMo layer on a high-strength IN625 substrate to improve the corrosion resistance of the core parts of a valve. This study found that when the laser volumetric energy density (E_V) ≤ 20, the tensile strength increases linearly with the increase in E_V, and the slope of the curve is approximately 85°. The larger the slope, the greater the impact of E_V on the intensity. When E_V > 20, the sample strength reaches the maximum tensile strength. When the E_V increases from 0 to 20, the fracture position of the sample shifts from CoCrMo to IN625. When E_V ≤ 38, the strain increases linearly with the increase in E_V, and the slope of the curve is approximately 67.5°. The sample strain rate reaches the maximum when E_V > 38. Therefore, for an optimal sample strength and strain, E_V should be greater than 38. This study provides theoretical and technical support for the manufacturing of corrosion-resistant dissimilar metal parts using LPBF technology. Full article