Thin Layer Research Articles

Characterization of thin oxide layers formed by Ti-Nb Alloy anodization

Ti-Nb alloys are gaining more prominence in the industrial and scientific environment due to their high biocompatibility, mechanical strength/weight ratio, and exceptional corrosion resistance compared to other metallic materials. Metals exhibiting this passivation characteristic are known as metal valves and may exhibit semiconductive or insulating oxides. Controlling the growth of distinct thickness layer films is possible through tunning anodization conditions. In this work, a Ti-Nb binary system is anodized, and the grown oxide layer is comprehensively characterized using ellipsometry based on its optical properties and thickness at different applied potentials. Confocal Microscopy assessed their surface roughness, and SEM/EDS probed the surface material's elemental composition. CF-LIBS successfully confirmed the 70/30 composition of the Ti-Nb alloy. Raman spectra have detected the presence of amorphous TiO2 and Nb2O5 at potentials higher than 80V, 100V, and 120V. Finally, a linear dependence of the oxide thickness with the applied potential was observed.

Advances in Aerogels Formulations for Pulmonary Targeted Delivery of Therapeutic Agents: Safety, Efficacy and Regulatory Aspects.

Aerogels are the 3D network of organic, inorganic, composite, layered, or hybrid-type materials that are used to increase the solubility of Class 1 (low solubility and high permeability) and Class 4 (poor solubility and low permeability) molecules. This approach improves systemic drug absorption due to the alveoli's broad surface area, thin epithelial layer, and high vascularization. Local therapies are more effective and have fewer side effects than systemic distribution because inhalation treatment targets the specific location and raises drug concentration in the lungs. The present manuscript aims to explore various aspects of aerogel formulations for pulmonary targeted delivery of active pharmaceutical agents. The manuscript also discusses the safety, efficacy, and regulatory aspects of aerogel formulations. According to projections, the global respiratory drug market is growing 4-6% annually, with short-term development potential. The proliferation of literature on pulmonary medicine delivery, especially in recent years, shows increased interest. Aerogels come in various technologies and compositions, but any aerogel used in a biological system must be constructed of a material that is biocompatible and, ideally, biodegradable. Aerogels are made via "supercritical processing". After many liquid phase iterations using organic solvents, supercritical extraction, and drying are performed. Moreover, the sol-gel polymerization process makes inorganic aerogels from TMOS or TEOS, the less hazardous silane. The resulting aerogels were shown to be mostly loaded with pharmaceutically active chemicals, such as furosemide-sodium, penbutolol-hemisulfate, and methylprednisolone. For biotechnology, pharmaceutical sciences, biosensors, and diagnostics, these aerogels have mostly been researched. Although aerogels are made of many different materials and methods, any aerogel utilized in a biological system needs to be made of a substance that is both biocompatible and, preferably, biodegradable. In conclusion, aerogel-based pulmonary drug delivery systems can be used in biomedicine and non-biomedicine applications for improved sustainability, mechanical properties, biodegradability, and biocompatibility. This covers scaffolds, aerogels, and nanoparticles. Furthermore, biopolymers have been described, including cellulose nanocrystals (CNC) and MXenes. A safety regulatory database is necessary to offer direction on the commercialization potential of aerogelbased formulations. After that, enormous efforts are discovered to be performed to synthesize an effective aerogel, particularly to shorten the drying period, which ultimately modifies the efficacy. As a result, there is an urgent need to enhance the performance going forward.

Enhanced photocatalytic hydrogen evolution via yolk–heteroshell TiO2@TiO2/SiO2 nanoreactor with confined Pt nanoparticles

The upper limit of photocatalytic efficiency is largely determined by the light-harvesting capability of a semiconductor. To address this challenge, we developed a yolk-heteroshell TiO2@TiO2/SiO2 (T@T/S) nanoreactor, leveraging a novel design based on an in-depth understanding and innovative utilization of light-matter interactions. The T@T/S nanoreactor significantly enhances solar light capture and utilization efficiency through total internal reflection mechanisms facilitated by the heterogeneous shell. This heteroshell, consisting of an outer SiO2 shell an inner monolayer of TiO2 nanoparticles, maximizes light confinement due to the different refractive indices of SiO2 and TiO2, while also minimizing mass transfer resistance due to the thin inner shell layer. These unique structural features result in high photocatalytic activity under simulated solar light. Additionally, we successfully applied a “ship-in-a-bottle” strategy for the confined growth of platinum nanoparticles within T@T/S nanoreactor. The Pt0.5-T@T/S nanoreactors demonstrated excellent hydrogen production, achieving a hydrogen evolution rate of 24.43 mmol g−1h−1 under simulated sunlight and an apparent quantum efficiency (AQE) of 7.8 % at 350 nm. This study highlights the importance of nano-engineered designs in optimizing semiconductor photocatalysts and shows the significant potential of our approach for sustainable energy conversion and environmental protection.

Unraveling the SCC behavior and enhanced creep strength mechanism of AFA alloy in supercritical CO2

The oxide scale of 20Cr25Ni2.5Al AFA alloy formed under the coupling of stress and supercritical carbon dioxide (sCO2, 650 ℃ / 15MPa) consisted of Fe3O4, Cr2O3, preferential intergranular oxidation zones, but lacked a thin Al2O3 protective layer. The poor oxidation resistance resulted in significant CO2 penetration into the matrix and subsequent formation of Cr2O3, thereby hindering the initiation of Cr - rich σ phase beneath the oxide scale. This competition between oxidation and precipitation effectively reduced crack initiation and delayed the connection between SCC and creep cracks, thus significantly prolonging the creep lifetime in sCO2 compared to that in air.

Viscoelastic material enhancement of underwater sound absorption in higher-order resonators: from low-frequency to ultra-broadband

Underwater noise control is crucial for improving the marine acoustic environment. This study introduces a novel underwater acoustic absorber design that integrates viscoelastic materials with higher-order resonance structures to enhance the absorption efficiency of low-frequency sound waves. By embedding a thin layer of rubber within a conventional second-order Helmholtz resonator, the rubber's viscoelastic and damping properties significantly improve this structure's underwater low-frequency acoustic performance. Theoretical and simulation calculations have shown that the structure has two perfect absorption peaks in the low-frequency range. The simulation results show that in the frequency range of 415-1848 Hz (Simulation), only four units are needed to effectively absorb up to 90% of noise energy, and the total volume is only. Moreover, the absorber maintains excellent absorption performance over a wide range of incidence angles from 0 to 60 degrees. This work is helpful to design ultra-thin low-frequency underwater absorbers.

Plasma enhanced chemical vapor deposition (PECVD) of SiOx thin films on Portuguese limestone: An experimental study

Plasma Enhanced Chemical Vapor Deposition (PECVD) of SiOx thin films has been applied to the stone surface under laboratory conditions in order to assess its feasibility as an alternative method for stone protection. SiOx thin layers were deposited on oolitic limestone lithologies known to have been used for the construction and restoration of the Batalha Monastery in Portugal surface by PECVD from tetraethoxysilane (TEOS) as the reaction precursor, in capacitively coupled parallel-plate reactor. The thickness, morphologies and chemical properties of the deposited film were characterized by attenuated total reflectance -Fourier transform infrared (ATR-FTIR) spectroscopy and scanning electron microscopy (SEM+EDS). Laboratory simulated decay and natural aging tests were implemented to evaluate the protective effect of the deposited micron-size SiOx thin films. Results suggested that, due to the good barrier effect, SiOx films were able to isolate the stones from aggressive acidic solution, thus reducing possible dissolution-related damage. Natural aging tests proved that SiOx thin films were also able to inhibit to a high extent bio-colonization while, at the same time reducing soiling of the stone appearance. Durability and wetting property of this SiOx thin film were preliminarily assessed. This research tested, for the first time, the feasibility of applying micron-size SiOx film quickly and directly via cold plasma deposition and its versatile protection performance on carbonate stone.

Development of liposomal amniotic mesenchymal stem cell metabolite products (AMSC-MP) loaded-scaffold for in vitro osteogenesis induction

The use of scaffolds with good biocompatibility and mechanical properties largely determines the success of bone defect therapy intended to improve quality-adjusted life years. Furthermore, amniotic mesenchymal stem cell metabolite product (AMSC-MP) is required to accelerate bone regeneration with sustained release required to maximize the effectiveness of therapy. This study aims to evaluate the effect of different phospholipids on the osteogenesis capacity of AMSC-MP liposome loaded into scaffold. The thin layer hydration method was employed to create the AMSC-MP liposomes which had different lipid components: L-α-phosphatidylcholine (PC) an unsaturated or hydrogenated soybean phosphatidylcholine (HSPC), a saturated phospholipid, with different types of charged phospholipids i.e., 1,2-dioleoyltrimethylammoniumpropane (DOTAP) or 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), which were cationic and non-ionic lipids respectively.AMSC-MP liposomes were embedded in the scaffold during a 24-hour incubation period. The results indicated that the particle sizes of liposomes prepared with saturated phospholipids, HS-DOTAP (132.35 ± 2.75 nm) and HS-DOTAP (152.85 ± 5.86 nm) were larger than those with saturated phospholipids, namely PC-DOTAP (139.355 ± 2.75 nm) and PC-DOTAP (91.85 ± 0.07 nm). The use of DOTAP in AMSC-liposomes resulted in positively charged vesicles i.e., +5 mV for HSPC-DOTAP and + 10 mV for PC-DOTAP. Moreover, the results of an MTT viability test conducted on 7f2 cells and MSC indicated that all the formulas demonstrate good in vitro biocompatibility. Formulations containing DOPE produced high cellular uptake values and had superior sustain release properties compared to the others. This result correlates positively with cell attachment to the liposome scaffold which was higher than the others. Moreover, DOPE-containing formulations increased RUNX2 expression, indicating enhanced in vitro osteogenesis capacity. Therefore, Liposome AMSC-MP loaded scaffold demonstrates high potential for use in bone regeneration therapy.

Chemical and electrochemical repair methods for the anchorage regions of grouted, post-tensioned concrete systems

Grouted, post-tensioned concrete systems are commonly used for constructing bridges with an intended corrosion-free service life of 100+ years. However, the use of inadequate grout materials and improper grouting techniques have caused voids at the anchorage regions – resulting in premature corrosion (say, within one or two decades) of strands. In addition, re-grouting the voids with repair grout has aggravated the corrosion of strands at the interface between the base grout (usually carbonated) and repair grout due to the differences in their chemical properties – raising concerns and leading to reluctance in re-grouting the voids in tendons. This work focused on developing non-invasive chemical (re-alkalization) and electrochemical (galvanic cathodic protection) methods to repair the anchorages of grouted, post-tensioned concrete systems. Immersion experiments were conducted to assess the efficiency of alkaline solutions in re-alkalizing the carbonated grouts. It was found that 1M Ca(OH)2 solution can restore the pH of the carbonated grouts in about a day. Moreover, the electrochemical impedance spectroscopy studies indicated that 1M Ca(OH)2 solution can re-passivate the embedded strands within a week. It can be sometimes challenging to achieve complete re-alkalization and re-grouting of voids; hence, a redundant electrochemical system that could work from outside the anchorage was found necessary. Therefore, experiments were conducted to evaluate the viability of galvanic anodes in protecting the anchorages. It was found that a thin layer of grout surrounding the strand would be sufficient to provide ionic conductivity for the galvanic anode (connected to the strand-end outside the anchorage) to protect the strand portions inside the anchorage. Based on the study, recommendations for the repair of the anchorage regions using chemical and electrochemical methods are presented.

89Zr-Labeled DFO@Durvalumab-HSA nanoparticles: In vitro potential for triple-negative breast cancer.

This study presents the development and evaluation of a DFO@mAb-NP (DFO@Durvalumab-HSA-DTX nanoparticle) nanoplatform for imaging in triple-negative breast cancer (TNBC). The nanoplatform demonstrated significant changes postconjugation with DFO, evidenced by increased particle size from 178.1 ± 5 nm to 311 ± 26 nm and zeta potential alteration from -31.9 ± 3 mV to -40.5 ± 0.8 mV. Fourier-transform infrared spectroscopy and ultraviolet spectral analyses confirmed successful DFO conjugation, with notable shifts in peak wavelengths. High labeling efficiency was achieved with 89Zr, as indicated by thin layer radio chromatography and high-performance liquid radio chromatography results, with labeling efficiencies of 98 ± 2% for 89Zr-DFO@mAb and 96 ± 3% for 89Zr-DFO@mAb-NP. The nanoplatforms maintained stability over 24 h, showing less than 5% degradation. Lipophilicity assays revealed logP values of 0.5 ± 0.03 for 89Zr-DFO@mAb-NP and 0.98 ± 0.2 for 89Zr-DFO@mAb, indicating a higher lipophilic tendency in the radiolabeled Durvalumab. Cell uptake experiments showed an initial high uptake in MDA-MB-468 cells (45.1 ± 3.2%), which decreased over time, highlighting receptor-specific interactions. These comprehensive findings suggest the promising potential of the DFO@mAb-NP nanoplatform for targeted imaging in TNBC, with implications for improved diagnostic accuracy and treatment strategies.

Antioxidant potential and xanthine oxidase inhibition of flavonol glycosides from Phyllanthus emblica L. leaves

Context: Hyperuricemia is the cause of gout in the inflammatory joint condition. The xanthine oxidase enzyme is a therapeutic target for gout treatment because it plays a role in the generation of uric acid. Allopurinol is used to treat gout. It prevents the xanthine oxidase enzyme from producing as much uric acid. When selecting a medication, one must consider the various adverse effects of allopurinol. Phyllanthus emblica plants are among the medicinal plants that can be used as an alternative treatment for gout. Aims: To evaluate isolated compounds from the Phyllanthus emblica as antihyperuricemia candidates. Methods: The isolated compounds were characterized using High-Performance Liquid Chromatography Analysis and Thin Layer Chromatography-Densitometry. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) and cupric ion (CUPRAC) antioxidant capacity procedures were used to develop the antioxidant activity index. The ability to inhibit xanthine oxidase was determined using a spectrophotometer. Results: Compound 1 was indicated as rutin having antioxidant capacity with an antioxidant activity index (AAI) DPPH value of 7.89 ± 0.03 and AAI CUPRAC value of 15.83 ± 0.04 stronger than compound 2 (quercitrin) with an AAI DPPH value of 3.72 ± 0.01 and AAI CUPRAC 3.24 ± 0.03. The IC50 for quercitrin's inhibition of xanthine oxidase is 23.85 ± 2.04, which was higher than rutin’s IC50 value of 32.77 ± 4.49 µg/mL. Conclusions: Flavonol glycosides present in the ethanol extract of Phyllanthus emblica leaves gave potent xanthine oxidase inhibitory activity stronger than the extract. Quercitrin gave stronger xanthine oxidase inhibitory activity, but this compound has weaker antioxidant capacity compared to rutin.

Geophysical characterization of the bedrock and regolith in the Pranmati basin critical zone, Uttarakhand Himalaya

The young active Himalayan mountain is characterized by steep slope and dissected topography in overall compressive tectonic setting. The mountain belt has primarily coarse textured soil with poor water holding capacity and is highly prone to erosion. The erosion not only affects many ecosystems located at downstream but also has detrimental effects on the critical zone (CZ). In the present study, we have carried out DC electrical resistivity study in the Pranmati catchment of the Alaknanda basin, a Himalayan critical zone in the Lesser Himalaya, to understand the pattern of soil erosion, transportation and deposition by characterizing the bedrock architecture and hence regolith thickness. A total of 6 electrical resistivity tomogram (ERT) profiles were laid at two locations in the catchment, one in a plain grassland and another at a crop field located on a hill slope of >25o. The study area in the Baijnath klippe, consists of quartz-biotite gneisses with layers of quartz mica-schist enclosed by thrust faults. Electrical resistivity sections of the downslope grassland site show a sharp resistivity contrast between the southwest and northeast transects suggesting south-eastern increase in dip of the bedrock, oblique to the north-east facing surface topography and a thick regolith (> 10 m). The resistivity sections of the site located on the hillslope yield a very thin layer of regolith (< 2 m) indicating significant soil erosion and high weathering of the bedrock. We propose that the water–rock interaction within the porous regolith facilitated by subsurface water circulation might be a potential source for the thick regolith. The observations substantiate existing hypotheses for the evolution and development of deep critical zones. From the results, it has been hypothesized that the bedrock architecture and water channel paths within the CZ together control the regolith thickness.

Advancing Multi‐Optical Performances in Lanthanide‐Doped Fluoride Core@Shell Nanoarchitectures by Minimizing Cation Intermixing

AbstractCore/shell structures are widely employed to enhance photoluminescence efficiency and manipulate excitation dynamics in lanthanide‐doped fluoride nanoparticles (NPs). However, prominent cation intermixing leads to significant deviations from the expected optical performances, presenting a formidable challenge in a deeper understanding of the chemical processes involved, as well as developing efficient suppression methods. Here, a reliable and facile multi‐optical reference strategy to reveal the integral cation intermixing processes is designed. This strategy analyzes the presence of Ce3+ ions in the core (or shell) and their influences on near‐infrared light‐triggered upconversion (UC), ultraviolet (UV)‐activated downshifting (DS), and X‐ray‐excited optical/persistent luminescence (XEOL/XEPL) of Tb3+ ions in the shell (or core). The results demonstrate that a thin surface layer of core NPs dissolves to reach dissolution equilibrium, which then distributes throughout the entire shell layer, rather than being confined to an interfacial region. It is further developed an improved technique to greatly inhibit cation intermixing by successive shell growth with excessive cation precursors, enabling superior multi‐optical performances, including UC, DS, XEOL/XEPL, and time‐dependent multicolor evolution. The findings significantly advance the development of lanthanide‐doped fluoride core/shell NPs with superior optical performances, broadening their potential applications in bio‐medicine, healthcare, industrial inspection, and optical information science.

Large eddy simulation of near-surface boundary layer dynamics over patchy snow

The near-surface boundary layer over patchy snow is highly heterogeneous and dynamic. Layers of opposing stability coexist within only a few horizontal meters. Conventional experimental methods to investigate this layer suffer from limitations related to the fixed positions of eddy covariance sensors. To overcome these difficulties, we set up a centimeter-resolution large eddy simulation of flow across an idealised transition from bare ground to snow. We force the simulation with high-frequency eddy covariance data recorded during a field campaign. We show that the model can represent the real flow by comparing it to independent eddy covariance data. However, the simulation underestimates vertical wind speed fluctuations, especially at high frequencies. Sensitivity analyses show that this is influenced by grid resolution and surface roughness representation but not much by subgrid-scale parameterization. Nevertheless, the model can reproduce the experimentally observed plumes of warm air intermittently detaching from bare ground and being advected over snow. This process is highly dynamic, with time scales of only a few seconds. We can show that the growth of a stable internal boundary layer adjacent to the snow surface can be approximated by a power law. With low wind speeds, deeper stable layers develop, while strong wind speeds limit the growth. Even close to the surface, the buoyancy fluxes are heterogeneous and driven by terrain variations, which also induce the frequent decoupling of a thin layer adjacent to the snow surface. Our simulations point the path towards generalizing point-based and aerial measurements to three dimensions.

A Flexible Organomagnetic Single-Layer Composite Film with Built-In Multistimuli Responsivity.

Materials possessing multiple properties and functionalities, that can be controlled or modulated by external stimuli, are a central focus of current research in materials sciences due to their potential to significantly enhance various future technological applications. Herein, we report a significant advancement in this field through the development of a smart, multifunctional organomagnetic composite material. By utilizing a thin layer of polydimethylsiloxane (PDMS) and polypyrrole (PPy) precursors, doped with nickel nanoparticles (NiNPs), we have created an innovative organomagnetic, PDMS/PPy/NiNPs (PPN), single-layer composite film that displays multistimuli responsivity. The study presents the first demonstration of a multifunctional flexible, three-component film structure integrating the structural and flexible PDMS component, together with a conductive polymer component and metal-based nanoparticles into a single-layer design, which displays enhanced and unprecedented responsivity properties against multiple different stimuli. Unlike typical stacked multilayered structures, that exhibit one or two functionalities at most, this novel configuration exhibits multiple functionalities, including magnetoresistance, mechanical stress response, piezoresistivity, and temperature change sensitivity. The as-prepared film demonstrates notable magnetoresistance responsivity, with a relative electrical resistance, ΔR/R0, changing under a weak magnetic field and under ambient conditions. The significance of our study lies in the film's versatility, stability, and sensitivity, especially within the physiological temperature range, making it highly relevant for future biomedical applications. Furthemore, the film's sensitivity to mechanical deformation reveals an impressive piezoresistance behavior. Unlike existing multilayer architectures of higher complexity, our single-layer thin film offers a simpler, more flexible, and reliable solution with a broad range of stimuli-sensing capabilities. The significance of this novel multiresponsive composite material is underscored by the growing demand for advanced materials in biomedical devices, magnetic switches, sensors, electronic skin, transistors, and organic spintronic devices. These promising organomagnetic self-standing layers provide a robust platform for future technological innovations.

Inclined bending seismic reflection layer in the crust illuminated by distributed fibre-optic-sensing measurements in western Japan

Distributed acoustic sensing (DAS), which enables a single fibre-optic cable to function as multiple sensors, is a technique to measure the strain rate distributed along the cable. This technique is applied to record ground motions in western Japan via a 50 km-long fibre-optic cable beneath a national road. The measured values are strain changes along the cable every 5 m, corresponding to 9788 sensor deployments. This high-density measurement along the long cable successfully recorded the 2021 M2.8 and M3.2 earthquakes that occurred in the crust within the distance of the cable in southern Kyoto. The direct S waves were followed by seismic waves approximately 8–14 s later, which were reflected by lower crustal structures. These waveforms were previously reported by observing many earthquakes via multiple seismometers, but the DAS observations clearly illuminate reflected wavefields from single earthquake observations for the first time. The numerical simulation of the strain-rate wavefields of these earthquakes reveals the existence of a north-dipping thin layer with a slow seismic velocity in the lower crust, which becomes steeper in the shallower part. This layer might represent the path of slab-derived fluid to the shallow fault zone.

Contributions of Colloidal Forces to the Heterogeneous Separation of Stable Oil-In-Water Emulsions.

We use theory to study the distribution of spherical emulsion oil droplets in water near a lipophilic surface as a guideline for designing membranes for oil/water phase separation. Heterogeneous phase separations are shown in our laboratory using hydrophilic and hydrophobic membrane designs, where the affinity of the membrane surface to one of the phases in the mixture locally increases its concentration. Considering a colloidal emulsion (nano- to microemulsions) of spherical and noncoalescing droplets, we assess the contribution of colloidal forces, i.e., van der Waals, electrical double layer, and hydrophobic interactions and the finite size of the droplets to the accumulation of spherical emulsion droplets near a surface. We use our theory to study an experiment-inspired case study and find that an isolated lipophilic membrane surface in contact with an oil-in-water emulsion supports the oil-enriched emulsion phase in a thin layer near the membrane surface, suggesting that a membrane pore size comparable to this thickness should support oil-enriched emulsion in the membrane pores and hence past the membrane.

Dynamic Water Microskin Induced by Photothermally Responsive Interpenetrating Hydrogel Networks for High‐Performance Light‐Tracking Water Evaporation

AbstractSolar‐driven interfacial water evaporation is attracting increasing attention as a promising environmentally‐friendly solution to freshwater scarcity. It has been proven that a thin water layer on photothermal materials can prevent solar energy from invalidly heating the excess water to enhance the evaporation rate. However, the current water layers are usually formed on inelastic materials via confined capillarity, which are static and uncontrollable. Herein, we propose a flexible hydrogel‐based photothermal conversion material with thermal responsiveness by facile frontal polymerization, which can generate a unique dynamic water microskin (DWMS) during the solar evaporation process. The copolymerized hydrogel, introduced by the second polymeric poly(vinyl alcohol) network and thermally responsive poly(N‐isopropylacrylamide) (PNIPAM), exhibits reinforced mechanical strength and photothermally triggers reversible shrinking/swelling cycles that enable a thin water layer (≈32 µm) to balance the feedwater supply and photothermic energy input dynamically. As a result, a stable superior vaporization rate of 8.7 kg m−2 h−1 is achieved based on a cylindrical hydrogel with 6 cm height under 1 sun. Moreover, the simultaneous responsive bending allows efficient omnidirectional solar evaporation by light‐tracking to ensure maximum perpendicular solar absorption, which provides an alternative strategy for durable high‐efficiency solar evaporators for effective thermal management and solar utilization.

Electro-discharge machining using copper-coated additively-manufactured AlSi10Mg electrodes

Customized fabrication of electrodes for electro-discharge machining (EDM) is considered as a useful emerging application of metal additive manufacturing technologies for building complex shaped tools in a short period of time. This approach of producing electrodes not only effectively addresses the design flexibility and complexity issues of the tools but also enables the use of various materials so as to ingrain the desired properties in them. The current study explores the production of laser powder bed fusion (LPBF) AlSi10Mg tools for machining of titanium alloy. Moreover, it explicitly assesses the machining performance of additively manufactured electrodes when the tools are subjected to a thin layer of copper coating. Three types of acidic baths are used for electroless coating of tools. The machining performance of the tools in terms of material removal rate, tool wear rate, surface crack density, surface roughness, white layer thickness, and microhardness of the white layer is compared for different electroless copper coating processes. It is observed that the coated tools significantly enhance material removal rate; however, uncoated LPBF tools exhibit superior surface morphology and surface roughness.

Influence of Ti Layers on the Efficiency of Solar Cells and the Reduction of Heat Transfer in Building-Integrated Photovoltaics

This study examined the potential application of metallic coatings to mitigate the adverse effects of ultraviolet (UV) and infrared (IR) light on photovoltaic modules. Titanium coatings were applied on low-iron glass surfaces using magnetron sputtering at powers of 1000, 1250, 1500, 1750, 2000, and 2500 W. The module with uncoated glass served as a reference. The Ti layer thickness varied from 7 nm to 20 nm. Transmittance and reflectance spectra were used to calculate visible light transmittance Lt, UV light transmittance Ltuv, solar transmittance g, and visible light reflectance Lr. The obtained parameters indicated that the thinnest Ti layer (1000 W) coating did not significantly affect light transmittance, but thicker layers did, altering the Lt, g, and Lr factors. However, every sample noticeably changed Ltuv, probably due to the natural formation of a UV-reflective thin TiO2 layer. The differences in fill factor (FF) were minimal, but thicker coatings resulted in lower open-circuit voltages (Uoc) and short-circuit currents (Isc), leading to a reduction in power conversion efficiency (PCE). Notably, a Ti coating deposited at 2500 W reduced the power of the photovoltaic module by 78% compared to the uncoated sample but may protect modules against the unwanted effects of overheating.

Numerical simulation on multi-well fracturing considering multiple thin layers in vertical direction

Multiwell fracturing is a key technology for developing shale gas and shale oil reservoirs. In this study, a multiple planar 3D (PL3D) fracture simulator that can capture multiple thin layers was developed to examine the propagation of multiple fractures during multicluster fracturing in multiple horizontal wells. The simulator considers multiple thin layers in the vertical direction. The results of the model are validated against the analytical solution of a single radial fracture and the implicit level set algorithm (ILSA). Using the simulator, a series of numerical simulations based on the field case are performed to investigate the fracture propagation mechanism of multiwell fracturing. The completion sequence, well placement pattern, well spacing, and cluster spacing are investigated to optimize the treatment parameters. The effective fracture area is used to quantitatively describe the stimulation effect. The adaptability of the completion sequence and well placement pattern is also analysed from the perspective of “frac hits”. The results show that the completion sequence has a critical influence on the stimulation effect and fracture geometry. From the perspective of avoiding “frac-hit” fractures, fracturing the low-stress layer can form an “artificial stress barrier”, which slightly protects the well from interference from other fractures. The staggered well pattern is better than the stacked well pattern. Compared with the stacked pattern, the staggered pattern can reduce the overlap area of fractures by 80 %, which greatly reduces the probability of “frac-hits”. With increasing well spacing from 200 m to 500 m, the fracture area increases by 25 %, and the degree of uneven stimulation between the two pay zones also increases by 6 %. Considering that a small well spacing is prone to “frac hits”, a large well spacing leads to an unstimulated area between two wells, and a 350 m well spacing is optimal. The effective fracture area decreases slightly with increasing perforation cluster spacing, but the fracture geometry becomes much more regular. The results can be helpful for the field design of multiwell fracturing.