Wet Solution Research Articles

Evaluation of Cathode α-NaFeO2 for Sodium-Ion Batteries

Lithium-ion batteries(LIBs) are rechargeable batteries that are indispensable to our daily lives, but the supply of lithium-ion batteries is expected to become more difficult as the market expands due to the constraints of lithium being a rare metal and a scarce resource. In recent years, sodium-ion batteries(SIBs) have much attracted attention as a secondary battery that can replace LIBs with less risk to resources and supply. α-NaFeO2 with a simple layered rock salt structure is well known as the cathode active material for SIBs. It does not contain any rare metals, but only iron which is abundant in the earth's crust, so it is expected to be environmentally friendly and low-cost to synthesize. However, a few paper has evaluated sodium ion batteries using α-NaFeO2 cathode, and only basic information such as synthesis methods and reaction potentials have been reported. In this study, we fabricated α-NaFeO2 and investigated the charge-discharge reaction of batteries using α-NaFeO2 in detail. The battery characteristics were evaluated for the prepared SIBs. α-NaFeO2 was prepared by a solid-state reaction from stoichiometric amounts of Na2O2(Sigma-Aldrich Co.) and Fe2O3(Rare-metalic Co.) as starting materials. Weighed powders were mixed using a mortar and pestle without any wet solution. The mixed powder was heated in an electric furnace at 650℃ for 20 h in air. After that, they was taken out from the furnace at 200℃ for preventing water absorption, and then immediately transferred into an argon-filled glove box. X-ray diffraction was carried out for analysis of crystal structure for prepared materials. Positive electrodes consisted of 70wt% α-NaFeO2, 20wt% acetylene black, and 10wt% PVDF, which were mixed with N-methlpyrrolidone and pasted Al foil as a current collector by doctor blade, and then dried at 120℃ in vacuum oven. After preparing cathode sheet, 10mm-diamater circle-shape cathode was prepared using punching machine. Anode sheet was also prepared using hard carbon and was made circle-shape anode with 16mm-diameter. 2032-type coin-cells were assembled in the argon filled glove box to evaluate electrode performance of α-NaFeO2. Electrolyte solution used was 1 mol/L NaPF6 dissolved in ethylene carbonate and dimethyl carbonate (EC:DMC=1:1 vol). The charge-discharge characteristics of the coin-cells were measured using constant-current mode, with a voltage range of 1.5 to 2.8 V. Reversible insertion and desorption of sodium was confirmed over three cycles, and the battery was found to have an average working voltage of about 2.3 V and a discharge capacity of about 40 mAh/g at the first cycle. However, after three cycles, the discharge capacity decreased and the battery no longer functioned as a battery. Compared to the previous study, the average working voltage was about 1 V lower and the discharge capacity was half the value. The reason for the low average working voltage should be the high reaction potential of the hard carbon we used. A possible reason for the low discharge capacity and the inability to function as a battery is that the surface of α-NaFeO2 may have reacted with carbon dioxide and water in the atmosphere under preparing situation, and also is SEI construction at the surface of α-NaFeO2. The XRD results of α-NaFeO2 stored in air and the increased resistance in the impedance results suggest this possibility. We are currently verifying the insertion-desorption potential of hard-carbon and the crystal state of α-NaFeO2 after charging and discharging, and are investigating the cause of the decrease in discharge capacity. We will report the results of these experiments.

Metasurface Optic Features Using Metal-Assisted Chemical Etching (MACE)

Metal-assisted chemical etching (MACE or MacEtch) is a versatile method for fabricating nano and micro-structured silicon (Si), which has garnered significant attention due to its potential applications in photovoltaics, sensors, and nanoelectronics. The process involves the oxidation of Si in the presence of a metal catalyst (typically noble metals like Au, Ag, or Pt) and a wet etch solution, usually comprising hydrofluoric acid (HF) and an oxidizing agent such as hydrogen peroxide (H2O2).Impressive work has already been completed in the two decades following the introduction of this method through the field of stain etching [1]. Researchers have reported anisotropic structures in silicon as high as 10,000:1 aspect ratio [2] and studied the impact of catalyst thickness [3], geometry [4], chemical ratios [5][6], and level of doping [7].In this work, we systematically tune the selectivity of the MACE process based on the geometry of desired structures, chemical ratios of HF, H2O2 and ethanol, silicon doping types, and characteristics of the metal catalyst targeting our desired metasurface optic features. We use statistical analysis such as ensemble machine learning algorithms to create an informed understanding and importance matrix for each of these variables, toward the purpose of creating refractive optical features in silicon. The important parameters in the desired final product are vertical sidewalls, 10:1 aspect ratio, minimized surface roughness in the field, an optimized geometry, and a target depth.This comprehensive statistical analysis contributes to a deeper understanding of the MACE process, offering valuable guidelines for optimizing etching conditions to achieve desired micron to nanometer structures in silicon. The findings hold promise for advancing the fabrication of silicon-based nano-devices, paving the way for novel applications in various technological fields. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525 SAND2024-04791A[1] X. Li and P. W. Bohn, "Metal-assisted chemical etching in HF/H2O2 produces porous silicon," Applied Physics Letters, vol. 77, no. 16, pp. 2572-2574, 2000, doi: 10.1063/1.1319191.[2] L. Romano et al., "Metal assisted chemical etching of silicon in the gas phase: a nanofabrication platform for X-ray optics," Nanoscale Horizons, 10.1039/C9NH00709A vol. 5, no. 5, pp. 869-879, 2020, doi: 10.1039/C9NH00709A.[3] Z. Huang et al., "Extended Arrays of Vertically Aligned Sub-10 nm Diameter [100] Si Nanowires by Metal-Assisted Chemical Etching," Nano Letters, vol. 8, no. 9, pp. 3046-3051, 2008/09/10 2008, doi: 10.1021/nl802324y.[4] P. Lianto, S.-Y. Yu, J. Wu, C. V. Thompson, and W. K. Choi, "Vertical etching with isolated catalysts in metal-assisted chemical etching of silicon," Nanoscale, vol. 4 23, pp. 7532-9, 2012. [Online]. Available: https://doi.org/10.1039/C2NR32350H.[5] C. Chartier, S. Bastide, and C. Lévy-Clément, "Metal-assisted chemical etching of silicon in HF–H2O2," Electrochimica Acta, vol. 53, no. 17, pp. 5509-5516, 2008/07/01/ 2008, doi: https://doi.org/10.1016/j.electacta.2008.03.009.[6] W. Chern et al., "Nonlithographic Patterning and Metal-Assisted Chemical Etching for Manufacturing of Tunable Light-Emitting Silicon Nanowire Arrays," Nano Letters, vol. 10, no. 5, pp. 1582-1588, 2010/05/12 2010, doi: 10.1021/nl903841a.[7] R. A. Lai, T. M. Hymel, V. K. Narasimhan, and Y. Cui, "Schottky Barrier Catalysis Mechanism in Metal-Assisted Chemical Etching of Silicon," ACS Applied Materials & Interfaces, vol. 8, no. 14, pp. 8875-8879, 2016/04/13 2016, doi: 10.1021/acsami.6b01020. Figure 1

Separation properties and fouling resistance of polyethersulfone membrane modified by fungal chitosan

This research explores the enhancement of polyethersulfone (PES) membranes through the incorporation of chitosan derived from the lignicolous fungus Ganoderma sp. Utilizing wet phase inversion and solution casting techniques, chitosan was successfully integrated into the PES matrix, as confirmed by Fourier Transform Infrared Spectroscopy (FT-IR), which indicated a high deacetylation degree of 75.7%. The incorporation of chitosan significantly increased the membrane hydrophilicity, as evidenced by a reduction in the water contact angle and a substantial improvement in pure water permeability, from 17.9 L m-2 h-1 bar-1 to 27.3 L m-2 h-1 bar-1. The membrane anti-fouling properties were also notably enhanced, with the Flux Recovery Ratio (FRR) increasing from approximately 60–80%. Moreover, the chitosan-modified PES/CS membrane, particularly at a 5% chitosan concentration, demonstrated exceptional efficacy in pollutant removal, achieving over 90% elimination of total suspended solids, cadmium (Cd), and lead (Pb), alongside a 79% reduction in color during the treatment of textile wastewater.

Durability of epoxy and vinyl ester polymers in wet, seawater, and seawater sea sand concrete environments: Molecular dynamics simulations

Epoxy and vinyl ester (VE) deteriorate under harsh environmental conditions typical of marine and offshore applications. Enhancing their performance requires a deeper understanding of their molecular-level interactions with these environments. This study uses molecular dynamics simulations to investigate the behavior of epoxy and VE under dry, wet, Na2SO4, NaCl, NaOH, KOH, and simulated seawater sea sand concrete (SWSSC) pore solution environments. The effect of temperatures ranging from 300 K to 368 K was also explored. Key parameters, such as radial distribution function, hydrogen bond dynamics, diffusion coefficients of water molecules and ions, swelling ratio, and glass transition temperature (Tg), were analyzed. Results show that epoxy is more sensitive to environmental effects than VE. In the dry state, three types of hydrogen bonds (H-bonds) were identified, with 64 % of the hydroxyl (OH) group involved in epoxy and 34 % in VE. As temperature increases, polymer chain interactions weaken, leading to a decrease in H-bonds, with epoxy showing a faster decline. Absorbed water molecules accumulate near the polymer polar sites, particularly at the OH groups, breaking some polymer-polymer H-bonds and forming new ones with the polymer polar sites. The hydrogen atoms of most absorbed water molecules orient away from the OH group, creating binding sites for water clustering through water-water H-bonds, leading to plasticization and potential hydrolytic degradation. Ions increase the number of polymer-water H-bonds, significantly decreasing polymer-polymer H-bonds (by 59.22 % for epoxy and 51.52 % for VE in SWSSC), thus accelerating material deterioration. Free volume distribution and dynamics, the transition between bound and free water, hydrogen bond dynamics, as well as ion hydration and dehydration collectively influence the water diffusion process in the polymer networks. Ion species diffuse much slower than water molecules, with epoxy showing higher permeability to Cl- and OH- compared to VE. Glass transition temperature (Tg) of both polymers is sensitive to environmental exposure, with epoxy being more affected. The detrimental effect on Tg is ranked as SWSSC > KOH > NaOH > NaCl > Na2SO4 > Wet. These findings provide new nanoscale insights into the interactions between polymers and SWSSC environments, offering a foundation for accurately predicting the durability of polymer-reinforced SWSSC.

Contact dermatitis secondary to povidone-iodine: A systematic review.

Cutaneous reactions to povidone (PVP)-iodine are widely reported; however, distinction between allergic and irritant reactions can be challenging. Free iodine is responsible for irritant reactions and is released when PVP-iodine is in a liquid state. The aim of this study was to review the clinical presentation and results of patch testing in patients with PVP-iodine contact dermatitis. A systematic review was conducted by searching Pubmed, MEDLINE, and Google Scholar databases for reports of contact dermatitis secondary to PVP-iodine. Data were collated including study design, patient age and gender identity, iodine exposure, skin biopsy findings, and patch test methodology and results. The search revealed 187 reports with 38 eligible studies; 30 case reports/case series and 8 retrospective cohort studies. Overall, there were 223 patients with PVP-iodine contact dermatitis. The commonest reaction was irritant contact dermatitis (51%), followed by allergic contact dermatitis (40%) and contact dermatitis not further specified (9%). Irritant reactions were characterised by burn-like morphology and, when due to surgical skin disinfectant, were often distant from the surgical incision site. Patch testing was most often performed with a 10% PVP-iodine aqueous solution; however, irritant reactions in controls occur. Various testing methods including iodine in petrolatum, ethanol, dried powder, and open application testing were described. Most reactions to PVP-iodine are irritant and patch testing using a closed-chamber method yields inconsistent results due to risk of irritation from free iodine release over the 2-day occlusion time. Surgeons should be aware of the risk of prolonged skin contact with wet iodine solution.

Study on the heat and mass transfer characteristics of wet air and solution on the surface of corrugated packings at lower ambient pressure

Study on the heat and mass transfer characteristics of wet air and solution on the surface of corrugated packings at lower ambient pressure

A Co(III)-peroxo-arylboronate complex formed by nucleophilic reaction of a Co(III)-peroxo species

In this work, we report the generation and characterization of two new Co(III)-peroxo complexes 2 and 3. 2 is best described as a mononuclear CoIII-(O2) complex that exhibits an 18O-isotope sensitive OO bond stretching vibration at 845(−49) cm−1, indicating a relatively weak peroxo moiety compared to those of other CoIII-(O2) complexes reported previously. Complex 3 is a CoIII-peroxo-arylboronate species having a rare {CoIIIOOBO} five-membered metallocycle, which is structurally characterized using X-ray crystallography. Investigations of the reaction mechanism using density functional theory calculations show that 2 likely undergoes a nucleophilic attack to an arylboronic acid, which is generated by hydrolysis of the BPh4− anion in wet acetonitrile solution, to first form a CoIII-peroxo-arylboronic acid adduct, followed by the loss of one benzene molecule to generate the five-membered metallocycle. The entire reaction is thermodynamically favorable. Taken together, the conversion of 2 to 3 represents the discovery of a novel nucleophilic reactivity that can be carried out by mononuclear Co(III)-peroxo complexes.

Development of Ge Isotropic Wet Etching Solution and its Application to High Quality Ge-on-Insulator Fabrication through the Etchback Method

Ge has many unique characteristics, such as high carrier mobility and a narrow bandgap corresponding to near-infrared wavelengths. To take advantage of the attractive characteristics of Ge, Ge-on-Insulator (GOI) structures are necessary. In this study, we focus on a direct wafer bonding and etchback method to fabricate GOI structures and explore appropriate etching solutions for the etchback. An HF + H2O2 + CH3COOH solution can isotropically etch Ge and improve surface uniformity. The resulting surfaces were sufficiently flat to achieve Schottky and MOS diodes showing good electrical characteristics of the same level as devices based on commercial mirror-polished Ge surfaces. We discuss the role of the chemicals in the etching solution in achieving the flat surface. We fabricated GOI structures and a back-gate GOI capacitor through direct wafer bonding of SiO2/Si and Al2O3/Ge with the etchback method using the solution. The resulting electrical characteristics are also explained using theoretical calculations. This approach might offer an alternative route to high-quality GOI fabrication.

Research on Hydrothermal Iron Removal From Wet Zinc Refining Solutions and Iron Residue Reduces Emissions

For the conventional wet zinc refining processes of the jarosite method and goethite method of iron removal, the process that existed was iron residue low iron, high zinc, large amount of residue, and high cost of harmless treatment, this paper carried out a study on hydrothermal iron removal from wet zinc refining solutions and an iron residue that reduces emissions. The results show that the reaction temperature is a prerequisite for the precipitation of Fe3+ to precipitate hematite (Fe2O3). Prolonging the reaction time can induce the conversion of jarosite (KFe3(SO4)2(OH)6) to hematite. Increasing the partial pressure of oxygen will accelerate the oxidation of Fe2+ to Fe3+ and promote the formation of the hematite phase. Under the optimized technical parameters of reaction temperature 180 °C, oxygen partial pressure 0.6 MPa, reaction time 3 h, and controlled alkali metal ion concentration, 92.49% of the iron in the solution was precipitated into the residue in the form of hematite(Fe2O3), and the precipitated iron residue contained 57.75% iron and 0.82% zinc; compared with the jarosite process, the amount of iron residue was reduced by about 65%, and the zinc content of iron residue was reduced by 5.86%. The use of hydrothermal mineralization iron precipitation processes can realize the mineralization precipitation of iron in solution under low-acid conditions and obtain hematite iron precipitation residue with iron content up to the industry standard of iron oxide. And can be realized for resource utilization, helping the wet process zinc industry to develop in a green and low-carbon direction.

Synthesis and mechanistic approach to investigate crystallite size of NbSe2 nanoparticles

Niobium diselenide (NbSe2) belongs to the class of transition metal dichalcogenides (TMDCs) and exhibits peculiar features such as charge density waves, superconductivity, and periodic crystal lattice distortion. The main focus of the article is the synthesis and characterisation of NbSe2 NPs utilising the wet chemical precursor solution route at room temperature, followed by in-depth x-ray diffraction (XRD) characterisation and analysis using the aforementioned techniques. The EDS result demonstrated that the NbSe2 NPs are devoid of impurities and close to stoichiometry. The sample has a crystalline hexagonal structure with the lattice constants a = b = 3.443Å, c = 12.576 Å, and α = β = 90°, γ = 120°, according to the XRD results. The work emphasises the need of comprehending how lattice strain and crystallite size affect physical attributes. x-ray peak broadening was used to study the epitaxial crystallisation of NbSe2 NPs. Various methods for determining crystallite size, such as the Williamson–Hall (W-H) method, Debye–Scherrer plots, uniform deformation model (UDM), uniform stress deformation model (USDM), uniform deformation energy density model (UDEDM), size strain plot (SSP) method, and Halder-Wagner (H-W) method, are employed to comprehensively analyse the nanoparticle characteristics, and additionally, high-resolution transmission electron microscopy (HRTEM) is employed to visualise the morphology and particle size distribution of the synthesised NbSe2 NPs. Physical parameters, including lattice stress, strain, and energy density, are also evaluated more precisely from the XRD pattern reflection peaks. The outcomes shed light on the interplay between crystallite size, lattice strain, and their effects on the material’s properties and showed excellent intercorrelation of the average crystallite sizes as estimated by employing various methods.

Corrosion protection effect of rust and scales: A “metal protects metal” perception by considering the examples of hematite and magnetite

AbstractThe present report proposes a contradictory remark on the idiom “Iron cuts Iron” that could be synonymized as “Metal cuts Metal” using the example of hematite and magnetite. Most metals and alloys are highly reactive, forming rusts and scales primarily consisting of metal oxides. The formation of metal oxide layers is known as passivation. Generally, passivated metallic surfaces provide anticorrosive protection by avoiding the attacks of corrosive species on the fresh metal surface; therefore, “Corrosion is a Necessary Evil (CNE).” Most passive films are protective, but not all, and their actual nature can be determined using the Pilling–Bedworth ratio (PBR). In dry conditions, passivation occurs spontaneously by the oxidation of metal atoms, but in aqueous media, some external additives, called passivators, are added to build the passive films. Herein, by considering examples of hematite and magnetite, the anticorrosive properties of rusts and scales are described in dry and wet (solution and coating) environments.

Solution-processed CsPbBr3 perovskite LEDs using blended-polymer additives for nearly 100% surface coverage

The all-inorganic perovskite material (CsPbBr3) is a promising light-emitting material due to its narrow color spectrum, wet solution processability, and cost-effectiveness. Despite such advantages, pinholes, poor surface coverage, and stability issues limit widespread applications of perovskite light-emitting devices (PeLEDs) in solid-state lighting applications. The performance of PeLEDs depends strongly on the morphological characteristics of the perovskite layer, with low surface coverage and surface roughness observed to lead to higher current leakage and lower current efficiency. We find that perovskite thin films blended with polymers to form composite layers effectively enhance the thin film’s surface coverage and uniformity, improving performance. We report CsPbBr3 PeLEDs with dual polymer additives, with a 12.1% reduction in the turn-on voltage (Von), a 97.21% reduction in leakage current density, a 200%+ enhancement in maximum brightness, and a 700% increase in power efficiency compared to a control CsPbBr3 device. To study the likely source of these enhancements, we have conducted a comparative film analysis of test and control devices using field-emission scanning electron microscopy and atomic force microscopy. A reduced crystal grain size (∼204nm to ∼101nm) and a nearly 100% (99.79%) surface coverage (compared to 79.53% found for control devices) suggest that the improved overall morphology and surface coverage likely play a significant role in the improved performance. Further, a reduction in surface roughness (∼45%) and the formation of a nearly pinhole-free film are observed to increase yield by 20%.

On the Electrochemical Properties of Carbon-Coated NaCrO2 for Na-Ion Batteries

NaCrO2 is a promising cathode for Na-ion batteries. However, further studies of the mechanisms controlling its specific capacities and cycle stability are needed for real-world applications in the future. This study reveals, for the first time, that the typical specific capacity of ~110 mAh/g reported by many researchers when the charge/discharge voltage window is set between 2.0 and 3.6 V vs. Na/Na+ is actually controlled by the low electronic conductivity at the electrode/electrolyte interface. Through wet solution mixing of NaCrO2 particles with carbon precursors, uniform carbon coating can be formed on the surface of NaCrO2 particles, leading to unprecedented specific capacities at 140 mAh/g, which is the highest specific capacity ever reported in the literature with the lower and upper cutoff voltages at the aforementioned values. However, such carbon-coated NaCrO2 with ultrahigh specific capacity does not improve cycle stability because with the specific capacity at 140 mAh/g the Na deintercalation during charge is more than 50% Na ions per formula unit of NaCrO2 which leads to irreversible redox reactions. The insights from this study provide a future direction to enhance the long-term cycle stability of NaCrO2 through integrating carbon coating and doping.

Reinforced integrated membrane electrode assembly based on ionomer wet-binding and ePTFE reinforcement strategy for proton exchange membrane fuel cells

Optimizing the structure of the membrane electrode assembly (MEA) is an effective strategy for improving the performance and durability of proton exchange membrane fuel cells. To prepare reinforced integrated MEAs, in this study, a wet ionomer solution coating with expanded polytetrafluoroethylene (ePTFE) reinforcement was deposited on a cathode gas diffusion electrode (GDE) surface and then wet-binding with the anode GDE. Reinforced integrated MEAs with different layers of ePTFE were prepared and their performance and mechanical durability were compared. The peak power densities of MEAs with single- and double-layer ePTFE reinforcements are 1.26 and 1.19 W cm−2, respectively, which are higher than that of conventional catalyst-coated membrane (CCM)-type MEA (1.04 W cm−2). The common defects in the direct membrane deposition-type MEA, including poor gas barrier ability and mechanical durability of the MEA, are essentially eliminated. The reinforced integrated MEAs have lower degradation than CCM-type MEA in humidity cycling conditions due to the restrictive effect of the ePTFE reinforcement in PEM and the supporting effect of the GDEs on both sides of the PEM. In addition, the double layers of the ePTFE reinforcement endow the MEAs with higher stability and further alleviated the mechanical degradation. The strategy of ionomer wet-binding and multilayered reinforcement provides a novel approach for fabricating MEAs with high performance and mechanical durability.

Stacked SiGe nanosheets p-FET for Sub-3 nm logic applications

The fabrication of vertically stacked SiGe nanosheet (NS) field-effect transistors (FETs) was demonstrated in this study. The key process technologies involved in this device fabrication are low pressure chemical vapor deposition SiGe/Si multilayer epitaxy, selective etching of Si layers over SiGe layers using tetramethyl-ammonium-hydroxide wet solution, and atomic layer deposition of Y2O3 gate dielectric. For the fabricated stacked SiGe NS p-GAAFETs with a gate length of 90 nm, ION/IOFF ratio of around 5.0 × 105 and subthreshold swing of 75 mV/dec were confirmed via electrical measurements. Moreover, owing to its high quality of Y2O3 gate dielectric, the device showed a very small drain-induced barrier-lowering phenomenon. These designs can improve the gate controllability of channel and device characteristics.

P‐40: TFT‐LCD a‐Si Wet Etch Technology

In this paper, we investigate a technology to change the method and principle of n+ a‐Si:H etching from conventional dry etch to the innovative wet etch in TFT LCD fabrication. The technology is based on the development of a new wet metal etching solution and the design of the thinnest film thickness of a‐Si:H in the industry, combined with the etching process development, to achieve the etching of two different film layers of metal and N+ a‐Si:H in the back channel of TFT switches in one‐ step(Abbreviated as NW process). The process can effectively improve the capacity of Dry Etch process (Skip N+ Dry Etch); improve the uniformity of back channel a‐Si:H Remain (16.3%‐ >7.6% ); improve product characteristics (Dark I on（ TFT working current） 5.5‐>6.0); improve yield (Yield rate↑0.3%).The process has been successfully developed for the first time in Wuhan BOE and has been widely used for batch products, meanwhile, the process has been extended to Hefei BOE and Fuzhou BOE, and other BOE line sites are also actively exploring the experiment.

Preparation of Polylactic Acid/Calcium Peroxide Composite Filaments for Fused Deposition Modelling.

Fused Deposition Modelling (FDM) 3D printers have gained significant popularity in the pharmaceutical and biomedical industries. In this study, a new biomaterial filament was developed by preparing a polylactic acid (PLA)/calcium peroxide (CPO) composite using wet solution mixing and extrusion. The content of CPO varied from 3% to 24% wt., and hot-melt extruder parameters were optimised to fabricate 3D printable composite filaments. The filaments were characterised using an X-ray diffraction analysis, surface morphology assessment, evaluation of filament extrudability, microstructural analysis, and examination of their rheological and mechanical properties. Our findings indicate that increasing the CPO content resulted in increased viscosity at 200 °C, while the PLA/CPO samples showed microstructural changes from crystalline to amorphous. The mechanical strength and ductility of the composite filaments decreased except for in the 6% CPO filament. Due to its acceptable surface morphology and strength, the PLA/CPO filament with 6% CPO was selected for printability testing. The 3D-printed sample of a bone scaffold exhibited good printing quality, demonstrating the potential of the PLA/CPO filament as an improved biocompatible filament for FDM 3D printing.

Fabrication and Characterization of Oxygen-Generating Polylactic Acid/Calcium Peroxide Composite Filaments for Bone Scaffolds.

The latest advancements in bone scaffold technology have introduced novel biomaterials that have the ability to generate oxygen when implanted, improving cell viability and tissue maturation. In this paper, we present a new oxygen-generating polylactic acid (PLA)/calcium peroxide (CPO) composite filament that can be used in 3D printing scaffolds. The composite material was prepared using a wet solution mixing method, followed by drying and hot melting extrusion. The concentration of calcium peroxide in the composite varied from 0% to 9%. The prepared filaments were characterized in terms of the presence of calcium peroxide, the generated oxygen release, porosity, and antibacterial activities. Data obtained from scanning electron microscopy and X-ray diffraction showed that the calcium peroxide remained stable in the composite. The maximum calcium and oxygen release was observed in filaments with a 6% calcium peroxide content. In addition, bacterial inhibition was achieved in samples with a calcium peroxide content of 6% or higher. These results indicate that an optimized PLA filament with a 6% calcium peroxide content holds great promise for improving bone generation through bone cell oxygenation and resistance to bacterial infections.

Developing TSV wet cleaning chemistry for quantum computing application

New 3D-integration routes for superconducting Josephson junction qubits include the development of an interposer die with through‑silicon vias (TSV) for vertical and compact interconnections. Since fluoropolymer dielectric residues remaining in the vias may be detrimental for subsequent processes or qubit functionality, they must be removed without damaging the structure or other materials. Therefore, we developed a new O2 plasma-free, selective and non-toxic wet cleaning solution that can remove both the fluoropolymer from the vias and the photoresist used for TSV patterning from the surface. Key formulation physico-chemical properties are discussed based on cleaning results obtained by scanning electron microscopy (SEM) and electron dispersive spectroscopy (EDS). Also discussed is evidence of the dissolution and removal of fluoropolymer formed during Bosch etching. Finally, SEM and time-of-flight secondary ion mass spectrometry (ToF-SIMS) analyses confirm complete removal of fluoropolymer residue from the vias. These encouraging results confirm a viable, manufacturable one-step wet cleaning process for TSVs designed for 3D packaging of qubits and other applications.

Deepwater Artificial Seabed (DAS) Production System: An Innovative Approach to Cost-Effective Deepwater and Ultra-Deepwater Field Developments

The prevailing offshore field development solutions, i.e., dry tree and wet tree systems, are confronted with serious technical and economic challenges in deep and ultra-deep waters resulting from the large depth of water, far offshore distance, and harsh ocean environmental conditions, as well as high cost. In response to these challenges, an innovative Deepwater Artificial Seabed (DAS) production system is proposed in this article. The DAS production system concentrates on well access and riser design, which enables shallow-water-rated subsea production systems to develop Deepwater (DW) and Ultra-Deepwater (UDW) fields. First, DW & UDW field development drivers are discussed and presented. This is followed by a detailed discussion of the merits and demerits of the prevailing dry tree and wet tree field development solutions. On this basis, the design philosophy and main characteristics of the DAS production system are presented and discussed in detail. Dynamic survival analysis for the fully coupled Floating Production Storage and Offloading (FPSO)-DAS production system is carried out. The artificial seabed stability is systematically investigated for both intact and damaged conditions. The global analysis results indicate that the DAS production system as developed experiences quasi-static responses even under extreme storm conditions, due to the location of the artificial seabed and the decoupling effects of the flexible jumpers. The new DAS production system is considered to be a competitive and cost-effective field development solution in depths of up to 3000 m.