Pressure Bar Research Articles

Identification of optimal laccases for chlorinated phenol degradation: Insights from molecular modelling, docking, dynamics, and free energy calculations

This study aimed to investigate the interactions between twenty different bacterial and fungal laccases and chlorinated phenols (CPs), which are listed as priority pollutants by the United States Environmental Protection Agency (USEPA). Molecular docking was used to identify the optimal laccase for degrading CPs out of twenty selected laccases to save time and reduce the in vitro selection of laccase for CPs degradation. The average binding energies of CPs with bacterial and fungal laccases were − 4.72 kcal/mol and − 5.21 kcal/mol, respectively. Based on the highest average binding energies Trametes versicolor (fungus) and Xanthomonas arboricola (bacteria) laccase apo and bound forms were investigated for stability and interaction dynamics using a 200 ns molecular dynamic simulation. The root mean square deviations (RMSD) of T. versicolor and X. arboricola laccase bound forms were within the 0.25 nm and 0.5 nm limit. The radius of gyration (Rg) for all laccases bound forms remained within the range from 1.88 to 2.24 nm with majority of residues in root mean square fluctuations (RMSF) were within the 0.24 nm and found consistent with the laccase apo values. In an aqueous solution, at ~300 K and ~ 1 bar pressure, laccase stability with CPs is facilitated by hydrophobic interactions, hydrogen bonds, and van der Waals forces. The corresponding computational insights will be advantageous for the selection, design and application in engineering of laccases for in vitro CPs degradation.

Efficient CO2 adsorption by deoiled flaxseed hydrochar.

This study optimizes CO2 adsorption using hydrochar from de-oiled flaxseed (FDOP), a waste byproduct of the oil extraction industry, through hydrothermal carbonization (HTC). The aim is to enhance CO2 capture sustainably and cost-effectively. Using Response Surface Methodology (RSM), in optimal conditions achieved 1153.26mg/g CO2 adsorption capacity under 215.15°C synthesis temperature, 3.05h synthesis time, 0.99M acid concentration, 8.997bar pressure, and 25.07°C adsorption temperature. Statistical analysis (F-value: 44.48, R²: 0.9705) confirmed strong model reliability. Kinetic analysis showed both physical and chemical adsorption, while thermodynamic analysis revealed exothermic behavior (ΔH° values: -46.697kJ/mol for M-225, -40.230kJ/mol for MA-203). After 10 regeneration cycles, the adsorption capacity was reduced by only 2.8% and 3.1%, indicating excellent recyclability. This study highlights FDOP-derived hydrochar as a highly efficient, low-cost adsorbent, offering industrial applications for carbon capture and waste management.

Room‐Temperature Reversible Hydrogen Storage in Scandium‐Decorated [6]Cycloparaphenylene: Computational Insights

ABSTRACTThis study discusses the hydrogen storage and delivery capacity of Sc‐decorated [6]cycloparaphenylene ([6]CPP) using dispersion‐corrected density functional theory calculations (DFT + D3). The scandium atoms are decorated over [6]CPP via Dewar coordination with an average binding energy of 1.33 eV. Each Sc atom stores up to 5H2 molecules in quasi‐molecular form at an average adsorption energy ranging from 0.23 to 0.36 eV/H2. The system's stability before and after H2 adsorption is checked using reactivity parameters. The maximum hydrogen gravimetric capacity of the system is found to be 7.68 wt% at low temperatures at 1–60 bar pressure. With an increase in temperature (300–420 K), the gravimetric density is more than 5.5 wt% (US‐DOE target) below 60 bar. Atom‐Centered Density Matrix Propagation (ADMP)‐molecular dynamics (MD) simulations reveal that the desorption of H2 molecules from [6]CPP starts at around 300 K/1 bar, and complete desorption occurs above 480 K. The minimum Van't Hoff desorption temperature for [6]CPP‐Sc is 296.9 K at 1 atm pressure. Insignificant change in the structure of [6]CPP‐Sc during adsorption and desorption processes promises stability and reversibility of the system. Hence, we believe that Sc‐decorated [6]CPP can be a promising candidate for hydrogen storage applications.

Dewatering and drying of Kombucha Bacterial Cellulose for preparation of biodegradable film for food packaging

Kombucha Bacterial Cellulose (KBC), obtained from waste products of kombucha fermentation, has potential applications in diverse fields. The present study used tea waste as a raw material for producing kombucha-like beverages and bacterial cellulose (BC). The in-situ dewatering and drying operations were performed to remove the high-water content from fermented KBC. Herein, the performance of BC in pressure-driven separation has been investigated as a function of dewatering pressure, drying temperature, and drying time in a multifunctional filtration cell. The Central Composite Design (CCD) was used to optimize the dewatering and drying parameters. The optimum conditions were found to be 4 bar pressure, 99 °C drying temperature, and 5 min drying time with a desirability value of 0.921. The predicted response values agreed with actual responses within 2.3–2.7 %. The dried films were prepared at optimized conditions and used to investigate thickness, density, mechanical properties, Fourier transform infrared, and scanning electron microscopy. The properties of KBC film varied as fermentation days increased. The KBC films' transparency decreased as thickness and density increased. The KBC film exhibits excellent mechanical properties such as tensile strength, maximum load, extension at the break, load at the break, and Young's modulus. The KBC films have been reported to be biodegradable and non-toxic and may be used for food packaging. Moreover, the present study successfully demonstrated that KBC packaging material could extend the shelf life of tomatoes by 13–15 days under accelerated conditions.

Sustainable Acid Mine Drainage Water Reclamation Using Silica-pectin Multichannel Tubular Membrane: A Comparison of Ultrafiltration Vs Pervaporation

The practice of coal mining has been demonstrated to exert a detrimental impact on the surrounding environment, particularly through the formation of acid mine drainage (AMD) ponds, which have the potential to pollute water sources. The reclamation of AMD is necessary to treat wastewater to ensure its safety for discharge into the environment and subsequent use as clean water. This study aims to treat AMD by comparing ultrafiltration (UF) and pervaporation (PV) processes utilizing silica-pectin multichannel membranes. The membranes were fabricated by coating silica-pectin sol on an inner surface of multichannel tubular support. The UF process was conducted under various pressures (1-3 bar), while the PV process was tested at various feed temperatures. Both permeate were collected and analyzed using several parameters (pH, Mn, and conductivity). The results showed that the UF process is more effective in collecting permeate flux over 136.6 L.h-1.m-2 at 3 bar pressure. Meanwhile, PV performs high permeate quality with Mn and conductivity rejection of 99.9 and 96.5%, respectively. Both UF and PV processes exhibit slightly increasing permeate pH with a range of 4.5-5.6. It concluded that multichannel silica-pectin membranes successfully reclamation AMD to enhance water quality. In addition, the UF process is more affordable for recycling AMD with high permeate flux, pretty good Mn, and conductivity rejection of over 95%.

Potassium sulphate production from an aqueous sodium sulphate from lead‐acid battery recycling: Impact of feedstock impurities on products yields

AbstractThe increasing demand for renewable energy highlights the need for efficient energy storage solutions. Despite various available technologies, lead‐acid batteries remain preferred for many industrial applications due to their inherent advantages. However, their expanded use necessitates proper waste management and recycling practices. During lead‐acid battery recycling, Na₂SO₄ is generated as a waste product, which cannot be directly sold due to quality concerns and limited market demand. Consequently, advanced waste management techniques are required to comply with government regulations on industrial waste disposal. Despite these challenges, Na2SO4 serves as a vital precursor for producing K2SO4, a valuable fertilizer. Prior research on the glaserite process for converting Na2SO4 to K2SO4 has assumed Na2SO4 to be pure—without traces of impurities. However, Na2SO4 recovered from battery recycling contains various contaminants. To address this, HSC Chemistry software was used to model K2SO4 and NaCl production from impure Na2SO4 and KCl, considering feed impurities. Under ideal conditions—a 1 bar pressure, 25°C feed temperature, and 40°C reactor temperature—over 90% yield of K2SO4 and NaCl was achieved in the absence of impurities. However, the addition of impurities resulted in a reduction in yields. Notably, impurity levels ranging from 1% to 4% by weight still allowed for yields exceeding 90%. Furthermore, a review of reactor compositions revealed a significant depletion of potassium and chlorine ions which are crucial for K2SO4 and NaCl production as impurity levels varied from 0% to 10%. These findings emphasize the negative impact of impurities on K2SO4 and NaCl yields.

Enhancing barrier properties of cellulose propionate films through the integration of ionic liquid: A study on water pressure resistance

This study pioneers the production of porous cellulose propionate (CP) films enhanced with tetrabutylammonium styrenesulfonate ([N4444][SS]), an ionic liquid, to bolster their resistance against water pressure. In contrast to polymer films with ionic liquids that have high moisture permeability, the CP/[N4444][SS] films exhibit remarkable water resistance even under 8 bar pressure. This is due to the physical cross-linking between the [N4444] ions and CP's polar groups, limiting CP chain mobility and thus reducing water interaction. Fourier-transform infrared spectroscopy confirmed these interactions, while scanning electron microscopy revealed a dense, unconnected porous structure. Thermogravimetric and differential scanning calorimetry analyses showed that adding [N4444][SS] increases the CP film's glass transition temperature, indicating enhanced thermal stability. Overall, the study demonstrates that integrating an ionic liquid into CP films significantly improves their barrier capabilities against water and pressure, which has broad implications for various industrial applications.

Enhancing surface integrity of additively manufactured Inconel 718 through numerical modeling of hydrostatic ball burnishing parameters using TOPSIS and ANOVA

Abstract Surface enhancement of laser powder bed fusion components is pivotal for their suitability in end-use applications. Hydrostatic ball burnishing, a mechanical surface hardening technique, induces compressive residual stress on the surface by the application of hydraulic force resulting in improved fatigue life of the material. This present study focuses on determining the optimum burnishing parameter combinations for better surface integrity (roughness, hardness, and residual stress) utilizing ANOVA and TOPSIS analysis. The cumulative performance score of the TOPSIS analysis states that the best parameter combination for Inconel 718 is found to be 300 bar pressure, 0.2mm burnishing width, and feed 800mm/min. The adjusted R² values of the ANOVA model for all three responses are 0.96, 0.93, and 0.94, confirming their close agreement with experimental results. With optimum parameters, the roughness decreased from 2.217μm to 0.305μm, Microhardness increased from 318.9HV to 475.9HV and residual stress was converted from tensile 216MPa to Compressive -54MPa demonstrating the significance of this process on surface enhancement.

Development of hard X-ray photoelectron spectroscopy in liquid cells using optimized microfabricated silicon nitride membranes.

We present first hard X-ray photoelectron spectroscopy (HAXPES) results of aqueous salt solutions and dispersions of gold nanoparticles in liquid cells equipped with specially designed microfabricated thin silicon nitride membranes, with thickness in the 15-25 nm range, mounted in a high-vacuum-compatible environment. The experiments have been performed at the HAXPES endstation of the GALAXIES beamline at the SOLEIL synchrotron radiation facility. The low-stress membranes are fabricated from 100 mm silicon wafers using standard lithography techniques. Platinum alignment marks are added to the chips hosting the membranes to facilitate the positioning of the X-ray beam on the membrane by detecting the corresponding photoemission lines. Two types of liquid cells have been used, a static one built on an Omicron-type sample holder with the liquid confined in the cell container, and a circulating liquid cell, in which the liquid can flow in order to mitigate the effects due to beam damage. We demonstrate that the membranes are mechanically robust and able to withstand 1 bar pressure difference between the liquid inside the cell and vacuum, and the intense synchrotron radiation beam during data acquisition. This opens up new opportunities for spectroscopic studies of liquids.

Electrospun nanofiber-supported thin-film composite membrane by introducing graphene oxide interlayer for water vapor/N2 separation

In response to the increasing challenge of global water scarcity, the need for alternative water resources has become increasingly critical. Membrane technologies for water vapor separation have emerged as promising approaches for water recovery and reuse. In this study, a polyethersulfone electrospun nanofiber-supported thin-film composite (eTFC) membrane structure with graphene oxide (GO) interlayer, specifically designed for water vapor/N2 separation was introduced. The interlayer was fabricated by controlling the deposition of GO on the electrospun nanofiber substrate. Subsequently, the thin-film was formed through interfacial polymerization using trimesoyl chloride and piperazine as monomers. All the prepared membranes were characterized using analytical techniques. Their water vapor separation performance was evaluated under different water activity conditions and compared to commercial membrane with similar average pore size. The optimized Gi-eTFC (with a GO interlayer of 0.4 mg) exhibited enhanced hydrophilicity, superior water vapor permeance of 3817 GPU, and a relatively high water vapor/N2 selectivity of 115, under conditions of 80 % relative humidity, 1 bar pressure, and a temperature of 30 °C. Gi-eTFC membranes with an optimized GO interlayer showed uniform and successful polyamide active-layer formation, confirming that the introduction of the GO interlayer and the use of nanofibers had a synergistic effect on improving water vapor separation performance.

Synergetic effect of hybrid surface treatment on the mechanical properties of adhesively bonded AA2024-T3 joints

ABSTRACT Improving the surface properties of AA2024-T3 aluminium alloys is crucial for achieving durable and sustainable joints. For this purpose, AA2024-T3 alloys were first sandblasted at 4, 5 and 6 bar pressures using aluminium oxide and glass sphere abrasives. Then, the sandblasted samples were subjected to the chemical surface treatment resulting in a hybrid surface process. The surface properties of sandblasted and hybrid surface-treated AA2024-T3 alloys were characterised by 3D image analysis, contact angle and roughness measurement. Additionally, single-lap joints were fabricated using adhesives with low and high viscosity. The effect of changes in the viscosity of adhesives and the surface properties of the AA2024-T3 on the mechanical properties of the joints has been analysed in detail. It was found that both sandblasting and hybrid surface treatments applied to AA2024-T3 alloys caused significant improvement in the mechanical properties of the joints. AA2024-T3 alloys, which were chemically surface treated after being sandblasted with glass spheres at 6 bar pressure, were joined using low and high viscosity adhesives, and the failure load of these joints increased by approximately 110% and 68%, respectively, compared to untreated samples. In the case of aluminium oxide usage, the increase rates were determined to be 93% and 43%.

Effect of Cu incorporation on Fe-based catalysts for selective CO2 hydrogenation to olefins

The process of converting CO2 into sustainable chemical feedstock and fuels through reaction with renewable hydrogen has been regarded as a promising direction in energy research. The enhancement of CO2 hydrogenation efficiency to produce valuable hydrocarbons (specifically olefins) on Fe catalysts through Cu modification has been extensively researched. However, there is ongoing vigorous debate regarding the impact of these modifications on catalytic properties and the underlying mechanism. When compared to unprompted iron-based catalysts for CO2 hydrogenation, the choice of desired products, such as C2-C4 and C5+, is relatively low. So, promoters are frequently employed to customize and enhance product distribution. This study investigates how adding Cu to Fe-based supported catalysts affects their performance in converting CO2 to hydrocarbons, with a specific emphasis on the interaction between Fe and Cu. To achieve this goal, catalysts were created using co-precipitation methods, varying the distribution of Fe and Cu within them. A set of composite catalysts underwent testing in a fixed bed setup using a reactant gas mixture at 350 °C and 30 bar pressure. Analysis techniques such as XRD, SEM, TEM, NH3-TPD, H2-TPR, and N2 adsorption-desorption isotherms revealed the presence of iron-copper interaction within the composite catalysts. This interaction between the two components synergistically enhances the catalytic activity in CO2 hydrogenation.

Construction of hollow core-shell ZnO@Co3O4 p-n heterojunction for CO2 cycloaddition under visible light irradiation

In comparison to a single semiconductor, constructing p-n heterojunctions represents an efficient strategy for enhancing photocatalytic activity because of their advantages in accelerating charge separation and promoting photoabsorption. Herein, we propose a novel metal–organic framework (MOF)-assisted and controlled pyrolysis strategy for constructing a hollow core-shell p-n heterojunction photocatalyst ZnO@Co3O4. It is worth noting that the hollow core-shell heterojunction not only provides abundant active sites but also significantly facilitates the separation of photogenerated charge carriers and accelerates electron transfer. Benefiting from the above advantages, the optimized ZnO@Co3O4(400,2), obtained by pyrolysis at 400 ℃ for 2h using Zn-MOF@Co-MOF as a precursor, exhibits high activity for the cycloaddition of CO2 and epichlorohydrin, resulting in a 94% yield of 4-(chloromethyl)-1, 3-dioxolan-2-one under 1bar CO2 pressure and visible light irradiation for 2h, which is significantly superior to those of ZnO(400,2) (5%), Co3O4(400,2) (38%), and the physically mixed counterparts (55%). This work provides insightful guidance for designing efficient photocatalysts aimed at CO2 cycloaddition, thereby achieving solar to high-value-added chemical conversion efficiencies.

Finding high-performance MOFs for effective SF6/N2 separation through high-throughput computational screening and machine learning

Abstract Given the rapidly expanding pool of synthesized and hypothetical metal–organic frameworks (MOFs), testing every single material for SF6/N2 separation by iterative experimental methods or computationally demanding molecular simulations is not practical. In this study, we integrated high-throughput computational screening and machine learning (ML) approaches to evaluate SF6/N2 mixture adsorption and separation performances of over 25 000 different types of synthesized and hypothetical MOFs (hypoMOFs), representing the largest set of structures studied for SF6/N2 separation to date. SF6/N2 mixture adsorption data that we produced for synthesized MOFs using molecular simulations were utilized to develop ML models to accurately and quickly predict SF6 and N2 uptakes, SF6/N2 selectivities, SF6 working capacities, adsorbent performance scores, and regenerabilities of both synthesized and hypoMOFs. Results showed the MOF space that we studied exhibits very high SF6/N2 selectivities in the range of 1.8–4204 at 1 bar in addition to high SF6 working capacities between 0.04–5.68 mol kg−1 at an adsorption pressure of 1 bar and desorption pressure of 0.1 bar at room temperature. The top-performing MOF adsorbents for SF6/N2 mixture separation were identified to have Zn, Cu, Ni metals; terphenyl, pyridine, naphthalene linkers; and medium pore sizes. Our comprehensive computational approach offers a highly efficient alternative to brute-force computer simulations by enabling the rapid assessment of the MOF adsorbents for SF6/N2 separation and provides molecular insights into the key structural features of the most promising adsorbents.

Dynamic analysis of green hydrogen production integrated with storage tanks: An economical assessment for different demands

The current study aims to investigate green hydrogen production by wind and solar energy with different hydrogen storage scenarios, taking into account the economic factors. The considered renewable energy sources (RESs) are a 3 MW wind turbine and a 3.54 MW solar photovoltaic (PV) system. System modeling is performed in TRNSYS, supplying the energy required by an electrolyzer. The goal of this research is to determine an optimal economic scenario using sensitivity analysis under the same electrolyzer capacity and renewable energy generation. The calculations for various hydrogen storage scenarios are examined and evaluated for different hydrogen sale prices ranging from 3 to 15 $/kg. Hydrogen production is sized with different storage scenarios and various demands under 200 bar and 350 bar pressures and on-grid/off-grid scenarios. Results show that for a 15 $/kg hydrogen price, the optimal scenario for hydrogen demand is 350 Nm³/hr in the on-grid scenario with a pressure of 350 bar. Likewise, for the rest of the considered hydrogen sale prices, the results are presented through a comprehensive study of different approaches. The results show that for lower hydrogen unit prices, the smaller tanks will be preferred, while for higher hydrogen prices, bigger tanks are preferred. In terms of emissions, for the same amount of hydrogen production, there will be 6350 tons of CO2 emission reduction when renewable resources are used instead of fossil fuel-based hydrogen production systems.

Impregnation Effect of Synthesized Fe3O4 Nanoparticles on the Jabon Wood’s Physical Properties

This study focused on characterizing synthetic magnetite (Fe3O4-NP) and evaluating the impregnated jabon wood’s physical properties. The co-precipitation method used for the synthesis of Fe3O4-NP, namely by mixing the iron solution (n/n Fe2+:Fe3+=1:2) with the strong base of sodium hydroxide (NaOH) (MG-S) and weak base of ammonium hydroxide (NH4OH) (MG-W) as precursors. The impregnation stage uses parameters of a -0.5 bar vacuum for half an hour and 2 bar pressure for 2 hours with magnetite concentrations of 1; 2.5; 5% w/v in a demineralized water solvent. Scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX) and Fourier transform infrared spectrometry (FTIR) confirmed the presence of Ferrum content and Fe-O functional group in both Fe3O4-NPs produced. The Fe3O4-NP size was also measured via the X-ray diffraction analysis, namely 34.54 nm for the MG-S and 39.24 nm for the MG-W. Magnetic strength obtained was 7.51 mT for the MG-S and 8.58 mT for the MG-W. The impregnated jabon wood’s physical properties also improved with indications of an increase in wood density, weight percent gain (WPG), bulking effect (BE), anti-swelling efficiency (ASE), and a decrease in water absorption (WA). The results showed the best treatments were MG-S 2.5% and MG-W 5%.

An experimental investigation of abrasive jet machining parameters for optimized surface finish of mild steel components

Abrasive jet machining is one of the unconventional machining processes that are initiated for alternations of surface characteristics of ductile materials, like mild steel, due to the entrainment of high-velocity abrasive particles. The present experimental investigation deals with the major process parameters of the AJM process, namely air pressure, standoff distance, and time of machining, on the average surface roughness (Ra) of mild steel specimens. Experiments were conducted on the self-developed AJM setup using aluminum oxide abrasive particles of an average size of 50 µm. The pressure of air is changed in three levels, 6, 7, and 8 bars. The standoff distance is taken as 2 mm constant for all the cases. The surface roughness was measured at machining times of 20, 40, and 45 seconds. The presence of the increase of air pressure from 6 to 8 bars applied for all the machining time showed an increasing influence on roughness, although always significant in Ra. For 8 bars of pressure and 45 s of machining, the minimum resulted in 1.39 µm, compared with 3.47-4.02 µm. The rate of decrease in surface roughness is sharp with increasing machining time from 20 to 40 seconds but marginal beyond that. An optimal machining time of 40–45 seconds was identified to obtain a minimum Ra. Capability of AJM as an effective technique to enhance the surface finish of mild steel components, and practical insight of this study is very useful toward optimization of process parameters for attaining the targeted surface quality. The results obtained may assist in expanding the industrial application of AJM toward the finishing of ductile materials in various manufacturing fields.

Functionalization of pyrolyzed hydrochar with nitrogen containing deep eutectic solvent for carbon capture at low and high pressure

The purpose of this research is to evaluate the effectiveness of pyrolyzed hydrochar functionalized with nitrogen containing deep eutectic solvent (DES) in the absorption of CO2 under low- and high-pressure conditions. Pyrolyzed hydrochars were synthesized by hydrothermally carbonizing pine at the temperature of 200°C and 260°C, followed by pyrolysis at 600°C. These pyrolyzed hydrochars were impregnated with 3 different nitrogen containing DES namely choline chloride: urea, choline chloride: glycerol, and tetrabutylammonium bromide: glycerol all in 1:2 molar ratio. It was found that the functionalized pyrolyzed hydrochars were enhanced with nitrogen and oxygen functionalities (N-H, C-N, and CO). The results also show a substantial reduction in surface area for the functionalized pyrolyzed hydrochars, ranging from 10.19 to 227.74 m2g−1, compared to the surface areas of pyrolyzed hydrochars of 306–337 m2g−1. On the other hand, an increase in N content up to 38 % was identified after functionalization of pyrolyzed hydrochars. Upon conducting CO2 uptake at low (0.1–1 bar) and high (2.5–3.5 bar) pressure, the functionalized pyrolyzed hydrochars exhibited an CO2 uptake of up to 9.5 mmol/g at high pressure, which was attributed to the increased total nitrogen content, enhanced surface functionalities, and available micropore volume. The low-pressure isotherm for functionalized pyrolyzed hydrochars showed Langmuir-type isotherm, suggesting a monolayer adsorption. In contrast, the high-pressure isotherms were better fitted to the Freundlich isotherm, suggesting a multilayer adsorption behavior. It was concluded that the enhanced CO2 uptake is the result of the combined impact of increased surface functionalities and porosity, which results in improved physical and chemical adsorption mechanisms at the high pressure.

Silica infiltration as a strategy to overcome zirconia degradation

The excellent clinical performance of yttria-partially stabilized zirconias (Y-SZs) makes them promising materials for indirect restorations. However, the Y-SZ phase stability is a concern, and infiltrating Y-SZs with a silica nanofilm may delay their degradation processes. In this study, we analyzed stabilities of silica-infiltrated zirconia surfaces after exposure to artificial aging (AA).Four zirconia materials with different translucencies (n = 40) were used, including low translucency 3 mol% Y-SZ (3Y-LT, Ceramill ZI, Amann Girrbach); high translucency 4 mol% Y-SZ (4Y-HT, Ceramill Zolid); and two high translucency 5 mol% Y-SZs (5Y-HT, Lava Esthetic, 3M and 5Y-SHT, Ceramill Zolid, FX white). Sintered specimens were exposed to 40 cycles of silica (SiO2) through room temperature atomic layer deposition (RT-ALD) using tetramethoxysilane (TMOS) and ammonium hydroxide (NH4OH). AA was applied for 15 h in an autoclave (134°C, 2 bar pressure). Stabilities of zirconia-silica surfaces were characterized in terms of hardness and Young's modulus using nanoindentation techniques and crystalline contents using x-ray diffraction (XRD) analyses. Silica deposition was also characterized by X-ray photoelectron spectroscopy (XPS).There was a significant effect of the interaction of materials and surface treatments on the hardness and Young's modulus values of zirconia-silica surfaces (p < 0.001). Silica deposition on zirconia surfaces improved the material resistance to degradation by AA.

A molecular dynamics study of the effect of initial pressure on the mechanical resilience of aluminum polycrystalline

Polycrystalline materials are essential in engineering due to their ability to withstand various forces, heat, and environmental conditions. The arrangement of atoms within these crystals significantly affects their mechanical properties. This study used molecular dynamics simulations to explore how initial pressure affects the mechanical resilience of aluminum polycrystals. Aluminum composite materials, known for their strength, flexibility, and environmental sustainability, are the focus of this investigation. We particularly investigated stress-strain reactions at 1, 2, and 3 bar initial pressures. Reduced free volume causes atomic migration to be hampered as pressure increases, therefore affecting mean square displacement and diffusion coefficient. The results show that ultimate strength and Young's modulus of the polycrystalline samples were 30 and 6.64 GPa at 1 bar pressure. Moreover, the results demonstrated a notable decrease in mechanical performance by increasing pressure; the ultimate strength and Young's modulus of the polycrystalline samples diminished to 5.66 GPa and 22.43 GPa, respectively, at 3 bar. Furthermore, the heat flux increased by rising initial pressure in the Al-polycrystalline sample due to the compression of material that reduced atomic distances. This improved atomic arrangement facilitated more efficient heat transfer. These insights are essential for engineering applications, as they establish a foundation for the production of aluminum components that maintain structural integrity in the face of extreme conditions.