Search Results (5,141)

Numerous studies on specific cannabis compounds (cannabinoids and phenolic acids) have demonstrated their therapeutic potential, with their administration methods remaining a key research focus. Transdermal drug delivery (TDD) systems are gaining attention due to their advantages, such as painless administration, controlled release, direct absorption into the bloodstream, and its ability to bypass hepatic metabolism. The thin films obtained via pulsed laser deposition consist of micro- and nanoparticles capable of migrating through skin pores upon contact. This study investigates the interaction of phenolic compounds in hemp seeds with pulsed laser beams. The main goal is to achieve the ablation and deposition of these compounds as thin films suitable for TDD applications. The other key objective is optimizing laser energy to enhance the industrial feasibility of this method. Thin layers were deposited on glass and hemp fabric using dual pulsed laser (DPL) ablation on a compressed hemp seed target held in a stainless steel ring. The target was irradiated for 30 min with two synchronized pulsed laser beams, each with parameters of 30 mJ, 532 nm, pulse width of 10 ns, and a repetition rate of 10 Hz. Each beam had an angle of incidence with the target surface of 45°, and the angle between the two beams was also 45°. To improve laser absorption, two approaches were used: (1) HS-DPL/glass and HS-DPL/hemp fabric, in which a portion of the stainless steel ring was included in the irradiated area, and (2) HST-DPL/glass and HST-DPL/hemp fabric—hemp seeds were mixed with turmeric powder, which is known to improve laser interaction and biocompatibility. The FTIR and Micro-FTIR spectroscopy (ATR) performed on thin films compared to the target material confirmed the presence of hemp-derived phenolic compounds, including tetrahydrocannabinol (THC), cannabidiol (CBD), ferulic acid, and coumaric acid, along with other functional groups such as amides. The ATR spectra have been validated against Gaussian 6 numerical simulations. Scanning electron microscopy (SEM) and substance transfer tests revealed the microgranular structure of thin films. Through the analyzes carried out, the following were highlighted: spherical structures (0.3–2 μm) for HS-DPL/glass, HS-DPL/hemp fabric, HST-DPL/glass, and HST-DPL/hemp fabric; larger spherical structures (8–13 μm) for HS-DPL/glass and HST-DPL/glass; angular, amorphous-like structures (~3.5 μm) for HS-DPL/glass; and crystalline-like structures (0.6–1.3 μm) for HST-DPL/glass. Microparticle transfer from thin films on the hemp fabric to the filter paper at a human body temperature (37 °C) confirmed their suitability for TDD applications, aligning with the “whole plant medicine” or “entourage effect” concept. Granular, composite, thin films were successfully developed, capable of releasing microparticles upon contact with a surface whose temperature is 37 °C, specific to the human body. Each of the microparticles in the thin films obtained with the DPL technique contains phenolic compounds (cannabinoids and phenolic acids) comparable to those in hemp seeds, effectively acting as “microseeds.” The obtained films are viable for TDD applications, while the DPL technique ensures industrial scalability due to its low laser energy requirements. Full article

This study investigated the influence of Cr, Mo, and W alloying elements incorporated into ferritic stainless steel on the characteristics of passive films formed under acidic chloride conditions. Electrochemical assessments demonstrated that increasing the amounts of Cr, Mo, and W reduces passive current density and enhances polarization resistance. Through XPS analysis, it was determined that the passive film exhibits a double-layer structure, consisting of an inner layer rich in metal oxides and an outer layer containing metal oxy-anions. Mott–Schottky analysis indicated the presence of both p-type and n-type semiconducting properties. To clarify the effect of these alloying elements on the passive films at the surface of stainless steel, this work introduces a new parameter termed the “Bipolar Index,” defined as |p-type slope| + |n-type slope|. With higher Cr, Mo, and W contents, the bipolar index increases, reflecting modifications in the semiconductive behavior. Consequently, the point defect concentration within the passive film decreases, causing a reduction in passive current density and a rise in polarization resistance. Full article

Monitoring of laser-based processes is essential for ensuring the quality of produced surface structures and for maintaining the process stability and reproducibility. Optical methods based on scatterometry are attractive for industrial monitoring as they are fast, non-contact, non-destructive, and can resolve features down to the sub-microscale. Here, Laser-Induced Periodic Surface Structures (LIPSS) are produced on stainless steel using ultrashort laser pulses in combination with a polygon scanning system. After the process, the fabricated LIPSS features are characterized by microscopy methods and with an optical setup based on scatterometry. Images of the diffraction patterns are collected and the intensity distribution analyzed and compared to the microscopy results in order to estimate the LIPSS height, spatial period, and regularity. The resulting analysis allows us to study LIPSS formation development, even when its characteristic diffraction pattern gradually changes from a double-sickle shape to a diffuse cloud. The scatterometry setup could be used to infer LIPSS height up to 420 nm, with an estimated average error of 7.7% for the highest structures and 11.4% in the whole working range. Periods estimation presents an average error of ~5% in the range where LIPSS are well-defined. In addition, the opening angle of the LIPSS was monitored and compared with regularity measurements, indicating that angles exceeding a certain threshold correspond to surfaces where sub-structures dominate over LIPSS. Full article

To enhance the wear resistance of laser-clad coatings, this study investigates the underlying modulation mechanisms of scanning speed on the microstructure and properties of TiC-TiB₂-reinforced 316L stainless steel composite coatings. TiC/TiB₂ particle-reinforced 316L stainless steel composite coatings were fabricated on 45# steel substrates via laser cladding. Our analysis reveals that scanning speed critically governs the thermal cycle of the melt pool, thereby modulating the coating’s microstructure and properties: Lower scanning speeds prolong melt pool duration, consequently intensifying ceramic particle dissolution, coarsening, and tendencies toward agglomeration and settling. Conversely, higher scanning speeds promote rapid solidification, which both preserves ceramic particles and refines the matrix grains. With increasing scanning speed, accelerated melt pool cooling rates drive a microstructural transition from coarse dendrites to refined equiaxed grains, accompanied by dramatically enhanced uniformity in ceramic particle distribution. Coatings deposited at higher scanning speeds exhibit a 22% increase in hardness compared to those at lower speeds. Wear resistance evolution parallels this hardness trend: at 480 mm/min scanning speed, wear reduction can be expected, with the wear volume decreasing by 58.60% and the friction coefficient reducing by 42.1% relative to 120 mm/min. Full article

The biocompatibility of orthodontic archwires is crucial for ensuring patient safety and the long-term success of orthodontic treatment. This study evaluated the biocompatibility of stainless steel (SS) and nickel–titanium (Ni-Ti) orthodontic archwires, as well as stainless steel metal brackets, before and after the application of a graphene coating. The assessment was based on the materials’ effects on a fibroblast cell line and on the development of a foetal chicken egg embryo. Fibroblasts that had been in temporary contact with steel and NiTi archwires after CW-CVD (cold wall chemical vapour deposition) treatment exhibited changes in morphology in the presence of the material. The materials exhibited moderate cytotoxicity. For metal brackets, the treated samples caused stronger cytotoxic changes in the culture. Unlike graphene-coated implants, where cells were found to directly adhere to the surface, the embryonic tissues did not treat the non-graphene-coated implants as an adhesive material. This study suggests that depositing carbon-based coatings, including graphene, on stainless steel archwires may reduce the cytotoxicity of orthodontic components. Using graphene increases adhesion of the implant surface to membrane-derived cells and the embryonic yolk and does not inhibit the further development of the chicken egg embryo. Full article

The degree of anisotropy and heterogeneity in coarse-grained materials significantly affects ultrasonic propagation behavior and scattering. This paper proposes a vector coherent factor threshold total focusing imaging method (VCF-T-TFM) for austenitic stainless steel, based on material properties, through a combination of simulation and experimentation. Three types of austenitic stainless steel weld test blocks with varying degrees of heterogeneity were selected containing multiple side-drilled hole defects, each with a diameter of 2 mm. Full-matrix data were collected using a 32-element phased array probe with a center frequency of 5 MHz. The grain size and orientation of the material were quantitatively observed via electron backscatter diffraction (EBSD). By combining the instantaneous phase distribution of the TFM image, the coarse-grained material coherence compensation value (C_A) and probability threshold (P_T) were optimized for different heterogeneous regions, and the vector coherence imaging threshold (γ) was adjusted. The defect imaging results of homogeneous material (carbon steel) and three austenitic stainless steels with different levels of heterogeneity were compared, and the influence of coarse-grained, anisotropic heterogeneous structures on the imaging signal-to-noise ratio was analyzed. The results show that the VCF-T-TFM, which considers the influence of material properties on phase coherence, can suppress structural noise. Compared to compensation results that did not account for material properties, the signal-to-noise ratio was improved by 97.3%. Full article

Understanding the combined gravi-phototropic behavior of plants is essential for space agriculture. Existing single-axis clinostats and gel-based grow media provide limited simulation fidelity. This study developed a Cloud-enabled triple-axis clinostat with built-in automated aeroponic and artificial photosynthetic lighting systems for Earth-based simulation under Martian gravity ranging from 0.35 to 0.4 g. Finite element analysis validated the stability and reliability of the acrylic and stainless steel rotating platform based on stress, strain, and thermal simulation tests. Arduino UNO microcontrollers were used to acquire and process sensor data to activate clinorotation and controlled environment systems. An Arduino ESP32 transmits grow chamber temperature, humidity, moisture, light intensity, and gravity sensor data to ThingSpeak and the Create IoT online platform for seamless monitoring and storage of enviro-physical data. The developed system can generate 0.252–0.460 g that suits the target Martian gravity. The combined gravi-phototropic tests confirmed that maize seedlings exposed to partial gravity and grown using the aeroponic approach have a shoot system growth driven by light availability (395–400 μmol/m²/s) across the partial gravity extremes. Root elongation is more responsive to gravity increase under higher partial gravity (0.375–0.4 g) even with low light availability. The developed soilless clinostat technology offers a scalable tool for simulating other high-value crops aside from maize. Full article

Plasma Electrolytic Polishing (PEP) is an advanced anodic process that enhances stainless steel surfaces through controlled electrochemical dissolution and plasma-mediated modification. This study demonstrates that PEP treatment of AISI 304 SS at 300 V in aqueous urea solution (3.0 wt.%)/NH₄NO₃ (0.25 wt.%) achieves remarkable improvements: surface roughness decreases by 54.6% (from 0.197 ± 0.023 μm to 0.0895 ± 0.0205 μm) with minimal mass loss (0.0035 g·cm⁻²) in just 20 min. Tafel analysis showed a 99% reduction in corrosion rate (0.00497 mm yr⁻¹) compared to untreated AISI 304 SS (0.094 mm yr⁻¹). Cyclic Potentiodynamic Polarization (CPDP) measurements indicated superior pitting resistance (E_pit = +0.423 vs. +0.486 V for PEP processing). XPS analysis elucidates the underlying mechanisms, showing a 91% increase in the Cr/Fe ratio (0.44 to 0.84) and complete transformation of surface oxides to protective Cr₂O₃ (57.34 wt.%) and Fe₃O₄ (55.88 wt.%), which collectively explain the enhanced corrosion resistance. Full article

Soil pollution by petroleum hydrocarbons is a problem of concern to researchers in various domains. Many depollution methods exist for these situations, but not in all cases can the pollutant be recovered. Soil, an important environmental factor, has to be kept clean and often has to be returned to agricultural use. A common situation of accidental soil pollution is the transportation of petroleum products through pipelines. In this paper, a study is presented that highlights a fast-acting option for significant pollutant recovery, thus limiting major soil pollution. A study on the use of electrodes to help achieve these objectives is proposed. Three working variants have been established, with different electrodes (stainless steel and copper). The degrees of depollution achieved during one week with a working voltage of 12 V were determined. The highest degree of depollution (52.94%) was obtained for copper electrodes. Although electrokinetic depollution is mainly applied to polluted waters and for the removal of metals, the method proved to be efficient also for an agricultural soil polluted with 7% diesel oil. Nutrients (NPKs) and wash water were analyzed before and after depollution to verify if secondary pollution was present. Full article

Styles are invasive medical devices that are visible on images and are used in several medical specialties, including cardiology, neurology, orthopaedics, anaesthesia, oto-rhino-laryngology (ENT), and dentistry. With their thin and flexible design, they allow for the optimal positioning and precise guidance of medical devices such as nerve stimulation, defibrillation, electrode positioning, and catheter insertion. Generally, they are made of stainless steel, offering a combination of rigidity and flexibility. The aim of this study is to evaluate the sensitivity of austenitic stainless steel 304L used for the manufacture of J-stylets in uniform, pitting, crevice, and intergranular corrosion. We follow the manufacturing process step by step in order to analyse the risks of corrosion sensitisation and the cumulative effects of various forms of degradation, which could lead to a significant release of metal cations. Another objective of this study is to determine the optimal heat treatment temperature to minimise sensitivity to the intergranular corrosion of 304L steel. Uniform corrosion: Two samples were taken at each stage of the manufacturing process (eight steps in total), in the form of rods. After one hour of immersion, potentiodynamic polarisation curves were plotted up to ±400 mV vs. SCE. A coulometric analysis was also performed by integrating the anode zone between E (i = 0) and +400 mV vs. SCE. The values obtained by integration are expressed as mC/cm². The test medium used was a simulated artificial plasma solution (9 g/L NaCl solution). Intergranular corrosion: (a) Chemical test: Thirty rod-shaped samples were tested, representing the eight manufacturing steps, as well as heat treatments at 500 °C, 620 °C, and 750 °C, in accordance with ASTM A262 (F method). (b) Electrochemical Potentiokinetic Reactivation (EPR) according to ASTM G108–94 (2015). Two samples were tested for each condition: without heat treatment and after treatments at 500 °C, 620 °C, and 750 °C. Release of cations: The release of metal ions was evaluated in the following two media: artificial sweat, according to EN 1811:2011+A1:2015, and bone plasma, according to the Fitton-Jackson and Burks-Peck method. Six samples that had been heat-treated at 500 °C for one hour were analysed. Results, discussions: (a) Analysis of the polarisation curves revealed significant disturbances in the heat treatment steps, as well as the μC/cm² quantities, which were between 150,000 and 400,000 compared to only 40–180 for the other manufacturing steps; (b) Electrochemical Potentiokinetic reactivation (EPR) tests indicated that the temperature of 500 °C was a good choice to limit 304L steel sensitisation in intergranular corrosion; and (c) the quantities of cations released in EN 1811 sweat were of the order of a few μg/cm² week, as for Fe: 2.31, Cr: 0.05, and Ni: 0.12. Full article

Achieving high efficiency and quality in millisecond pulsed laser drilling of metallic through-holes is contingent on precise process control. This study introduces a penetration detection-based method to determine the pulse count threshold, effectively overcoming the limitations of conventional approaches. We systematically investigated the effects of pulse energy, defocus, and beam expansion ratio on the drilling of 3 mm thick 304 stainless steel and TC4 titanium alloy. The experiments revealed that for stainless steel 304, the minimum taper angle was achieved at a pulse energy of 2.2 J, a defocus amount of −0.5 mm, and a beam expansion ratio of 2.5. Additionally, relatively high drilling efficiency was observed when the pulse energy ranged from 2.6 to 2.8 J, the defocus amount was −1 to 0 mm, and the beam expansion ratio was 3 to 4. For titanium alloy TC4, the minimum taper angle was achieved at a pulse energy of 2.6 J, a defocus amount of −0.5 mm, and a beam expansion ratio of 3.5. High drilling efficiency was recorded when the pulse energy was 2.8 J, the defocus amount was −0.5 mm, and the beam expansion ratio ranged from 2.5 to 3. When stainless steel 304 and titanium alloy TC4 were processed using the same laser parameters, the drilling efficiency of stainless steel 304 was higher than that of titanium alloy TC4 under the same conditions. This work provides a practical process control strategy and a valuable parameter database for high-quality, efficient laser drilling of these industrially important metals. Full article

This study investigates the effect of copper (Cu) and silver (Ag) additions on the electrochemical behavior of the Fe40Al intermetallic alloy in artificial saliva, aiming to evaluate its potential for biomedical applications such as dental implants. Alloys with varying concentrations of Ag (0.5, 1.0, and 3.0 wt%) and Cu (1.0, 3.0, and 5.0 wt%) were synthesized and exposed to a biomimetic electrolyte simulating oral conditions. Electrochemical techniques, including open circuit potential (OCP), linear polarization resistance (LPR), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS), were employed to assess corrosion performance. Results show that unmodified Fe40Al exhibits good corrosion resistance, attributed to the formation of a stable passive oxide layer. The addition of Cu, particularly at 3.0 wt%, significantly improved corrosion resistance, yielding lower corrosion current densities and higher polarization resistance and charge transfer resistance values, surpassing even 316L stainless steel in some metrics. Conversely, Ag additions led to a degradation of corrosion resistance, especially at 3.0 wt%, due to microstructural changes and the formation of metallic Ag precipitates, AgSCN, and galvanic cells, which promoted localized corrosion. EIS results revealed that Cu- and Ag-modified alloys developed less homogeneous and less protective passive layers over time, as indicated by increased double-layer capacitance (C_dl) and reduced constant phase element exponent (n_dl) values. Overall, the Fe40Al alloy shows intrinsic corrosion resistance in simulated physiological environments, and Cu additions can enhance this performance under controlled conditions. However, Ag additions negatively affect the protective behavior of the passive layer. These findings offer critical insight into the design of Fe-Al-based biomaterials for dental or biomedical applications where corrosion resistance and electrochemical stability are paramount. Full article

Uniform and graded BCC lattice cylindrical shells were proposed, and the corresponding structural specimens were fabricated with 316L stainless steel material. Experimental testing and numerical simulations were both utilized to investigate the quasi-static and dynamic compression behavior of the uniform and graded BCC lattice cylindrical shells. Finite element results were compared with the experimental results. Parametric studies were conducted to study the effects of relative density, gradient distribution, and loading velocity on the mechanical properties and deformation features. When the relative density increased from 9% to 25%, a 175% increase in SEA could be seen. Graded BCC lattice cylindrical shells almost exhibited the same mechanical performance. When compared with the SEA value under low-speed loading conditions, a 26.95% maximum increase could be witnessed in the graded-5 specimen under high-speed loading. Testing results indicated that the proposed uniform and graded BCC lattice cylindrical shells exhibited fascinating quasi-static and dynamic mechanical behavior, which provided guidance for the design and application of next-generation lightweight materials with excellent protective properties. Full article

This study assesses how different anode materials influence neutron production rates (NPRs) in multi-state fusion (MSF) reactors, with a particular focus on the effects of deuterium (D) pre-loading on the anode surface. Three types of mesh anodes were assessed: stainless steel (SS), zirconium (Zr), and D pre-loaded zirconium (ZrD). MSF operates using two electrodes to confine ions to various fusion reactions, including D-D and D-T. The reactor features a negatively biased central cathode and a grounded anode within a vacuum vessel. Neutrons and protons are produced through the application of high voltage (tens of kV) and current (tens of mA) on the system to spark the plasma and start the fusion. Assessments at voltages up to 50 kV and currents up to 30 mA showed that Zr mesh anodes produced higher NPRs than SS ones, reaching 1.912 at 30 kV. This increased performance is attributed to surface fusion processes occurring in the anode. These processes were further modified by the deuterium pre-loading in the ZrD anode, as compared to SS and Zr with 1.832 at 30 kV. The findings suggest that material properties and deuterium pre-loading play significant roles in optimizing the efficiency of MSF reactors and the NPR. Future research may explore the long-term stability and durability of these anode materials under continuous operation conditions to fully harness their potential in fusion energy applications. Full article

This review explores the pressing issue of soil degradation and contamination, highlighting their adverse environmental effects and the necessity for sustainable solutions. Soil degradation disrupts ecosystems and accelerates climate change, while soil contamination poses serious health risks to humans and wildlife. Recent advances in mitigation strategies demonstrate promising solutions, focusing on both degradation and contamination. This paper presents innovative methods, including the utilization of a dolomite–sewage sludge mixture to combat soil degradation effectively, enhancing soil fertility and supporting ecosystem restoration. Additionally, it introduces a novel approach using a dolomite–stainless steel slag mixture for petroleum hydrocarbon absorption, showcasing its efficacy in remediating contaminated sites. The results indicate significant improvements in soil health and a reduction in environmental pollutants, underscoring the potential of these mixtures to revolutionize soil management practices. Implementing such strategies not only mitigates degradation and contamination but also contributes to the sustainability of agricultural and natural ecosystems. This article aims to provide a comprehensive overview of these advancements, offering insights for researchers, policymakers, and environmental practitioners striving to foster a healthier and more sustainable environment. Full article