Conventional Process Research Articles

High‐frequency (470 kHz) ultrasonics‐assisted room temperature CO2 stripping and fate of Sono exposed solvent

AbstractBACKGROUNDThe conventional CO2 stripping process in solvent‐based postcombustion CO2 capture (PCCC) process uses heating to strip the CO2 (~120 °C). However, the challenges associated with this method are high energy consumption in degassing the CO2 from solvent, solvent loss and degradation resulting from the high –temperatures, resulting in high energy consumption typical of solvent‐based PCCC. The present study demonstrates the use of bath‐type sonication (470 kHz frequency) to remove CO2 from CO2 loaded 30 wt% Monoethanolamine under controlled temperature conditions. Solvent performance was evaluated following exposure to 2 h conventional heating and 75 h sonication.RESULTSIn a batch sono‐assisted process, CO2 stripping became possible at 17.5 °C compared to 102.2 °C using the conventional method. Increasing the sonication time led decreased carbon loading and increased stripping efficiency. The stripping rate was high at the initial stages of treatment. Evaluation of sono‐exposed solvents exhibited decreased pH during CO2 loading and decreased absorption capacity of the conventionally heated sample.CONCLUSIONThe sono‐assisted method consumes 3.57‐foldless energy than conventional heating. Its CO2 stripping rate was found to be higher within 5 min of sonication. Notably, the maximum temperature reached for the 1 h intervening mode of sonication at 470 kHz was 49.49 °C. The reduction in absorption capacity per hour of conventional heating was 24.5%, whereas for sonication it was <0.4% and solvent loss was 19.7% lower than conventional. There was no significant change in the color, pH and density of the sample. A 20.4% higher surface tension than that of the virgin sample was observed. © 2024 Society of Chemical Industry (SCI).

Enhancing Ultradeep Hydrodesulfurization of Coker Diesel through Adsorptive Predenitrogenation.

The petroleum refining industry places significant challenge in the production of ultralow-sulfur diesel (ULSD) from various middle distillates with high nitrogen concentration in an energy-efficient and cost-effective way to meet strict environmental regulations as coexisting nitrogen compounds significantly inhibit the ultradeep hydrodesulfurization (HDS). Among all of the approaches reported in the literature for this challenge, a combination of adsorptive denitrogenation (ADN) and HDS has attracted great attention. This study focuses on ultradeep HDS of coker diesel (CD) through a synergistic approach combining ADN over a carbon-based adsorbent and the current HDS process. The study found that the predenitrogenation significantly enhanced the HDS reactivity of CD and greatly reduced the start of run temperature for producing ULSD by even 20 °C, depending on the denitrogenation depth. It results in dominantly decreasing energy and H2 consumption in the HDS process, and increasing the lifetime of the catalyst. Furthermore, the predenitrogenation prior to HDS significantly improved the quality of the hydrodesulfurized product by decreasing aromatic content and density, increasing the cetane index, and improving the color and stability of the product as the HDS process for producing ULSD can be conducted at a much lower temperature. The study demonstrated the combination of ADN and HDS for producing ULSD from CD on a pilot unit scale, and the advantages and disadvantages of this combination were discussed in comparison with the conventional HDS process. In addition, it was found that there is a good linear relationship between the logarithm of the product sulfur concentration and the HDS reaction temperature, which can be used conveniently to predict the start-of-run temperature to achieve different sulfur levels.

Microwave-assisted catalytic dry reforming of methane with CO2 over nitrogen-doped catalysts derived from metal-organic frameworks

Dry reforming of methane (DRM) can convert CO2 into syngas for the production of fuels and chemicals, offering both environmental and energetic benefits. However, its large-scale industrial applications face challenges such as harsh reaction conditions and catalyst deactivation. In this study, metal–organic frameworks (MOFs) derived N-doped Ni-based bifunctional nanomaterials (Ni-Co/NC) were meticulously synthesized to function as microwave absorbers and catalysts. Efficient syngas production was achieved through the microwave-enhanced DRM process over Ni-Co/NC. The results showed that the Ni-Co/NC catalyst significantly increased the conversion of CH4 (∼93.2 %) and CO2 (∼94.8 %). By comparing the changes in the surface properties of the catalysts before and after N-doping, it was found that N-doping enhanced the interaction between the carrier and metal particles, improved the specific surface area and surface basicity, and inhibited the aggregation of metal particles, thereby enhancing catalytic activity. The reaction mechanism was investigated using in-situ infrared spectroscopy, revealing that the formation of intermediates such as carbonates, formates, O-H groups was crucial to improving catalytic activity and stability. Compared to conventional catalytic processes, the catalysts prepared in this study demonstrated stronger catalytic activity and stability in the microwave catalytic process.

Flame retardant epoxy vitrimers employing a Meldrum’s acid-functionalized and phosphorus-containing bisphenol compound as the cross-linking agent for conventional epoxy

In addition to recycling and reprocessing features, designs of vitrimers possessing critical properties required for conventional cross-linked polymers are of interest. In this work, a newly designed Meldrum’s acid (MA)-functionalized and phosphorus-containing bisphenol compound (P-MADV) compound is synthesized. Employing P-MADV as a curing agent, simultaneous formation of permanent and dynamic covalent linkages through one-pot reaction has been achieved in formation of flame retardant epoxy resin vitrimers. The newly synthesized P-MADV compound is an effective cross-linking agent for commercially-available epoxy resins for synthesis of flame-retardant epoxy vitrimers through the conventional cross-linking conditions and processes. The cross-linked epoxy vitrimer passes the flame test under UL 94V-0 specification contributed from the phosphorus-containing groups. The flame retardant vitrimer also exhibits a storage modulus of 1.2 GPa at 50 oC and a Tg (tanδ peak) of 185 oC, which are comparable to the values found with conventional phenolic novolac-cross-linked epoxy resin (storage modulus: 1.6 GPa; Tg: 155 oC). Without addition of catalysts for dynamic bond exchanging reaction, the cross-linked epoxy vitrimer shows stress relaxation time of 397 sec at 230 oC and an activation energy of stress relaxation of 97.8 kJ mol-1. The dynamic features warrant the epoxy vitrimer being recyclable under thermally pressing at 230 oC and 16 MPa for 1 h. The recycled samples exhibit thermal and mechanical properties being comparable to the pristine resin. This work has demonstrated an attractive approach for preparation of flame retardant epoxy resin vitrimers in viewpoints of both manufacturing processes and resins properties.

Use of artificial intelligence-powered ECG to differentiate between cardiac and pulmonary pathologies in patients with acute dyspnoea in the emergency department

BackgroundAcute dyspnoea is common in acute care settings. However, identifying the origin of dyspnoea in the emergency department (ED) is often challenging. We aimed to investigate whether our artificial intelligence...

Efficient photocatalytic degradation of ciprofloxacin using floating α-NiMoO4/mpg-C3N4/EP under visible light

Conventional water treatment processes often fail to effectively remove antibacterial drugs, necessitating advanced strategies. This study presents the synthesis of novel floating, visible light-active α-NiMoO4/mpg-C3N4/EP composites for the removal of ciprofloxacin (CFX), a widely used quinolone antibiotic, from water. These composites are easily recoverable, highly stable, and demonstrate excellent reusability. The optimal photocatalyst, NC-101/EP (α-NiMoO4/mpg-C3N4 = 10:1), achieved 96.2 ± 1.1% degradation of CFX at 1.6 g L-1 within 80 minutes under visible light, significantly outperforming previous benchmarks. This high efficiency is attributed to the formation of interfacial junctions and a built-in electric field, which enhanced charge transfer and hydroxyl radical generation through an S-scheme mechanism. Fluorescence spectroscopy provided precise monitoring of CFX degradation without interference from coexisting intermediates. Density functional theory (DFT) calculations revealed that hydroxyl radicals initiated highly favorable and spontaneous oxidation of CFX, with a reaction rate constant of 6.04 × 109 M-1 s-1. The preferred oxidation pathway followed the sequence: HO-addition > H-abstraction > single electron transfer. Four degradation pathways were identified, with key intermediates confirmed by high-resolution mass spectrometry. The process also significantly reduced CFX toxicity, ensuring minimal environmental impact. These findings position NC-101/EP as a promising photocatalyst for large-scale water treatment applications targeting antibiotic contamination.

Efficient catalysis for acidic methanol Oxidation: Exploration of a Low-Platinum quaternary alloy catalyst via a Two-Step method

The quest for platinum-based catalysts with enhanced catalytic efficacy and durability during the methanol oxidation reaction (MOR) has been a focal point in energy conversion science. Traditional platinum-based catalysts are often constrained by their high platinum content, which escalates economic costs and complicates experimental protocols. In this study, we introduce a low-platinum-loaded catalyst synthesized via a two-step method, which incorporates a four-component alloy. This innovative approach significantly reduces platinum content while maintaining superior catalytic performance through precise control over the alloy’s composition and structure. The two-step synthesis methodology streamlines the conventional multi-step processes, enhancing the catalyst preparation’s efficiency and reproducibility. The resulting PtCoSnCu/N-C alloy catalyst exhibits remarkable catalytic activity in methanol solution, with mass activity and specific activity that are 9.73 and 9.75 times higher, respectively, than those of commercial platinum on carbon (Pt/C) catalysts. Notably, the optimized PtCoSnCu/N-C alloy catalyst demonstrates exceptional long-term stability, outperforming Pt/C in aging and extended stability tests. Density functional theory (DFT) calculations elucidate the optimization of the electronic structure and the synergistic effect of surface atoms in the PtCoSnCu/N-C catalyst, which mitigates the adsorption energy of CO molecules and enhances the utilization rate of active sites during the oxidation process. This research presents a paradigm-shifting low-platinum catalyst strategy for methanol fuel cells, establishing a theoretical foundation for catalyst design and optimization.

Radio frequency plus heat for in-shell egg pasteurization

Less than 3 % of the eggs in the United States are sold pasteurized because of the long thermal process (~ 60 min). However, this represents a food safety risk because of the possible presence of Salmonella spp. inside the egg. This research studied the inactivation of S. typhimurium in in-shell eggs using the novel technology radio frequency (RF) to enhance their food safety, evaluating quality, presence of sub-lethally injured cells (SICs), and cell recovery (7 °C). Eggs were inoculated inside with S. typhimurium (105 CFU/egg) and processed with RF (40.68 MHz, 35 W, 4.5 min) followed by hot water spray (H, 56.7 °C, 20 min). The studied quality attributes were yolk color, Haugh unit, yolk index, shell breakage strength, yolk and albumen pH, and albumen degradation. ANOVA one–way was used to find significant differences (α = 0.05). RF plus heat can pasteurize the eggs after 24.5 min (5-log reduction). No SICs were detected in any of the samples, and cells did not recover after five days of storage (Limit of detection <1 log CFU/g). Most quality attributes were like the control eggs. Albumen degradation showed a significant difference (p < 0.05) after processing. RF represents a potential option to ensure the safety of in-shell eggs, preserving their quality. Industry relevanceMost in-shell eggs are sold unpasteurized worldwide with the potential risk of Salmonella spp. The conventional pasteurization process is a lengthy intervention that adds cost to the product and can damage the quality of eggs. Radio frequency plus heat pasteurization offers an alternative to pasteurizing in-shell eggs with a volumetric heating process that inactivates Salmonella cells inside the eggs and has minor effects on the quality of eggs. This technology is a novel option for the egg industry, providing high-quality and reasonably priced safe eggs.

Experimental and numerical investigation of sliding wear of heat-treated 316L stainless steel additively manufactured

Additive manufacturing (AM) of metal alloys using a laser as a machine tool is reaching levels of precision comparable to conventional processing methods. Stainless steel specimens fabricated by AM have been extensively evaluated in load-bearing applications, showing an adequate response concerning mechanical strength. However, research on wear behavior remains open to discussion. The present work evaluates the sliding wear response of 316L stainless steel fabricated by laser powder bed fusion in three conditions: (1) as-built, (2) stress-relieved at 550 °C, and (3) heat-treated at 1150 °C. A pin-on-disk tribometer and a nanoindentation tester were employed to assess the tribological response and compare it with the same cold drawing material. The wear track and volume loss were evaluated using a 3D surface profile meter. Furthermore, the finite element method was applied to validate the experimental results and obtain insights into the behavior of the pin and disk couple. The results show that the samples in the as-built condition exhibit higher wear resistance associated with higher hardness. Stress relief slightly alters the wear response, while heat treatment modifies the microstructure, reducing the sliding wear resistance. The wear of the heat-treated samples cannot be attributed to a single wear mechanism, a synergy between several sub-mechanisms, such as abrasion, adhesion, oxidation, and tribochemical reactions.

Self-Assembled Ultra-Long Hybrid Nanowire Formed by Simple Mixing: An Untapped Feature of Peroxydisulfate.

Peroxydisulfate (PDS), a popular molecule that is able to oxidize organic compounds, is garnering attention across various disciplines of chemistry, materials, pharmaceuticals, environmental remediation, and sustainability. Methylene blue (MB) is a model pollutant that can be readily oxidized by PDS-derived radicals. Unlike the conventional degradation process, here a reversible "dissolution-precipitation" phenomenon is discovered, triggered by a simple mixing of PDS and MB, revealing a novel application of PDS in fabricating self-assembled ultra-long nanowires with MB. This phenomenon is unique to PDS and MB, different from the traditional salting out or self-aggregation of dyes. Formation of nanowires facilitated by electrostatic interaction between S+ and O- moieties and π-π stacking is reversible, controlled by temperature and the solvent polarity. MB1-PDS-MB2 configuration (MB: PDS = 2:1) is theoretically predicted by density functional theory (DFT) calculations and further validated by stoichiometric ratios of carbon, sulfur, and nitrogen in the obtained precipitates (MBO). This untapped feature of PDS enables the development of colorimetric quantitative detection of PDS and sustainable dye recycling. Far more than those demonstrated cases, the potentialities of MBO as a nanomaterial merit further exploration.

BIOSYNTHESIZE NANOPARTICLES AS ADVANCED NANOCARRIERS FOR TARGETED THERAPEUTIC INTERVENTIONS IN DISEASE MANAGEMENT

Biosynthesized nanoparticles have emerged as cutting-edge nanocarriers for targeted therapeutic interventions in illness management, transforming medication delivery and treatment techniques. These nanoparticles provide a biocompatible and sustainable substitute for conventional synthetic processes since they are made utilizing biological systems including fungi, bacteria, and plants. They are perfect candidates for precision medicine because of their innate capacity to lower toxicity and increase bioavailability. Because of their distinct surface characteristics, biosynthesized nanoparticles are easily functionalized with therapeutic drugs, allowing for targeted distribution to sick cells or certain organs while reducing off-target effects. Additionally, the large surface area-to-volume ratio and nanoscale size promote better cellular absorption and regulated drug release, enhancing therapeutic efficacy. These nanoparticles' natural origin lowers their immunogenicity and adverse response risk, which enhances patient outcomes even more. Biosynthesized nanoparticles have demonstrated great promise in cancer therapy, including the ability to target tumor cells specifically, carry chemotherapy medications, and even combine with imaging agents for theragnostic uses. They also show promise in improving therapy specificity and lowering adverse effects in other diseases like infectious diseases, cardiovascular ailments, and neurological disorders. This study covers the developments in biosynthesized nanoparticles as nanocarriers, highlighting their importance in altering illness management through tailored therapeutics while evaluating the limitations and future prospects for their clinical translation.

Current status of technological advancement of ultrasound processing in the food industry and its SWOT analysis.

The use of conventional food processing techniques has almost vanished due to increase in demand with respect to time, thus opening new avenues for emerging technologies. Ultrasound (US) is a rapid, multifaceted, promising, and noninvasive green technology. It has attracted the attention of both industrial experts and scientists for its probable use in food processing and preservation. Using US, fully reproducible food processes can be accomplished in seconds or minutes with increased reliability, minimal processing cost, streamlined manipulation, elevated clarity to the end product, and expending only a fragment of the time and energy commonly required by conventional processes.This review emphasizes on the applications of ultrasound in different food sectors along with its certain limitations. Several operations such as microbial inactivation, enzyme inactivation, extraction, emulsification and fractionation in dairy industries, thermo-sonication in fruit juices have been discussed in detail. The US extracted dietary fiber consisted of increased amount of dietary fiber and trace elements in comparison to alkaline method. US initiate rapid creaming of milk fat, decreasing flavor loss and energy requirements thus enhancing the quality of end product. SWOT analysis has been carried out to pinpoint the strengths, weaknesses, opportunities and threats of sonication in various food industries.

Underwater in-situ plasma treatment of coarse wool fibers for scouring and bleaching

Wool, in its natural state, is laden with impurities such as grease, suint, dust, and vegetable matter on its surface, necessitating their removal for the wool to be suitable for various products. Traditional scouring methods involve the extensive use of water, detergents, and chemicals, leading to the generation of hazardous wastewater. Moreover, coarse fibers often require bleaching due to the retention of natural pigments during the scouring process. This study introduces an innovative and environmentally friendly plasma treatment for scouring and bleaching of the coarse wool fibers, referred here after as underwater in-situ plasma treatment (UIPT), which is entirely free from chemicals and detergents. Research includes a comparative analysis of UIPT, plasma-activated water (PAW), normal water (NW) and conventional wet-chemical process (CWP) for wool fiber scouring and bleaching. Surface morphology and surface chemistry analyses underscore the efficacy of UIPT in cleaning the coarse wool. The residual grease analysis demonstrated a substantial reduction in grease content of raw wool from 20% to 2% after plasma treatment, while the whiteness index of wool fibers increased from 48% to 70%.

Fabrication of asymmetric supercapacitors by laser processing of activated carbon-based electrodes produced from rice husk waste

The development of supercapacitors (SCs) by using carbon electrodes obtained from biomass waste simultaneously promotes the optimized use of the renewable energy by its high-powered storage, and the reduction of contamination in nature. Such industrial sector would be an excellent opportunity also for the developing nations, promoting their economic growth by the conversion of biowaste into added value goods. However, such carbon may not reach the desired performance for SCs. In this work, we used laser processing technology for enhancing the capacitance of SC electrodes composed of activated carbon obtained from rice husk produced in Nigerian farmlands. The activated carbon powder was synthesized by conventional carbonization-chemical activation processes and treated with microwaves. Afterwards, the CO2 laser processing of thin film electrodes composed of a mixture of the carbon powder with carbon black (conductive additive), and precursors as urea (for doping of the activated carbon with nitrogen), or manganese nitrate (for the crystallization of pseudocapacitive Mn3O4 nanoparticles on the carbon surface) was carried out for obtaining enhanced positrodes and negatrodes. The resulting hybrid electrodes exhibited a 3-fold increase of the capacitance (up to 134 F/g @ 10 mV/s) as compared to the raw carbon in the [0, 0.8] V potential window. Asymmetric SC devices integrated by carbon (-)//carbon-Mn3O4 (+) laser-treated electrodes, operating at 1.2 V voltage, revealed up to 300 × higher energy and power densities than symmetric SCs composed of raw carbon electrodes.

Few-Shot Symbol Detection in Engineering Drawings

ABSTRACT Recently, there has been significant interest in digitizing engineering drawings due to their complexity and practical benefits. Symbol digitization, a critical aspect in this field, is challenging as utilizing Deep Learning-based methods to recognize symbols of interest requires a large number of training instances for each class of symbols. Acquiring and annotating sufficient diagrams is difficult due to concerns about confidentiality and availability. The conventional manual annotation process is time-consuming, costly, and prone to human error. Additionally, obtaining an adequate number of samples for rare classes proves to be exceptionally challenging. This paper introduces a few-shot framework to address these challenges. Several experiments with fewer than ten, and sometimes just one, training instance per class using complex engineering drawings from industry sources were carried out. The results suggest that our method not only significantly improves symbol detection performance compared to other state-of-the-art methods but also decreases the necessary number of training instances.

Industrial IoT-Based Energy Monitoring System: Using Data Processing at Edge

Edge-assisted IoT technologies combined with conventional industrial processes help evolve diverse applications under the Industrial IoT (IIoT) and Industry 4.0 era by bringing cloud computing technologies near the hardware. The resulting innovations offer intelligent management of the industrial ecosystems, focusing on increasing productivity and reducing running costs by processing massive data locally. In this research, we design, develop, and implement an IIoT and edge-based system to monitor the energy consumption of a factory floor’s stationary and mobile assets using wireless and wired energy meters. Once the edge receives the meter’s data, it stores the information in the database server, followed by the data processing method to find nine additional analytical parameters. The edge also provides a master user interface (UI) for comparative analysis and individual UI for in-depth energy usage insights, followed by activity and inactivity alarms and daily reporting features via email. Moreover, the edge uses a data-filtering technique to send a single wireless meter’s data to the cloud for remote energy and alarm monitoring per project scope. Based on the evaluation, the edge server efficiently processes the data with an average CPU utilization of up to 5.58% while avoiding measurement errors due to random power failures throughout the day.

Effects of finishing processes on physical properties of knitted fabrics produced by recycled cotton fibers

This study examines conventional wet-finishing processes applicable to fabrics containing recycled cotton fibers. The knitted fabrics were produced using open-end and compact yarns, with up to 80% of the cotton fibers being obtained from mechanical recycling of pre-consumer textile wastes. The study evaluated the effects of these finishing processes on the physical properties of the fabrics based on the recycled fiber ratio, yarn type, and yarn count. After determining the parameters for enzymatic bio-polishing, scouring, and color removal processes, two sequential finishing routes were designed: using the fabrics as mélange without a dyeing process (F1) or coloring them with color stripping and subsequent dyeing (F2). The resulting fabrics were tested for bursting strength, pilling resistance, weight, thickness, air permeability, and abrasion resistance, and the results were evaluated statistically. The study demonstrated that compact yarns provide superior strength, particularly when the F2 process was employed. The F2 process resulted in high pilling resistance and increased breathability of recycled knitted fabrics. The study concluded that the quality of fabrics containing recycled cotton fibers could be optimized by the selection of the appropriate finishing processes.

Pulsed Unipolar-Polarisation Plasma Electrolytic Polishing of Ni-Based Superalloys: A Proof of Conception

The enhanced performance of aerospace equipment drives parts development towards integration, complexity, and structural optimization. This advancement promotes metal near-net fabrication technologies like wire electrical discharge machining (WEDM) and 3D printing. However, the high initial surface roughness from WEDM or 3D printing poses significant challenges for the high-performance surface finishing required. To effectively reduce the surface roughness of the workpieces with high initial surface roughness, this paper proposes pulsed unipolar-polarisation plasma electrolytic polishing (PUP-PEP). The study examined the material removal mechanisms and surface polishing quality of PUP-PEP. This technique combines the high current density and material removal rate of the electrolytic polishing mode with the superior surface polishing quality of PEP through voltage waveform modulation. For an Inconel-718 superalloy part fabricated by WEDM, PUP-PEP reduced surface roughness from Ra 7.39 μm to Ra 0.27 μm in 6 min under optimal conditions. The roughness decreased from Ra 7.39 μm to Ra 0.78 μm in the first 3 min under pulsed unipolar-polarisation voltage, resulting in a remarkable 233% increase in efficiency compared to that with conventional PEP. Subsequently, the voltage output voltage is transformed into a constant voltage mode, and PEP is continued based on PUP-PEP to finally reduce the workpiece surface roughness value to Ra 0.27 μm. The proposed PUP-PEP technology marks the implementation of ‘polishing’ instead of conventional rough-finish machining processes, presenting a new approach to the surface post-processing of metal near-net fabrication technologies.

Effect of aging on dimensional accuracy and color stability of CAD-CAM milled and 3D-printed denture base resins: a comparative in-vitro study

BackgroundThere is a lack of studies comparing the dimensional accuracy and color stability of denture base resins made using computer-aided design and computer-aided manufacturing (CAD-CAM) milling, 3-dimensional (3D) printing, and conventional denture processing techniques. This makes it challenging to determine the best method to fabricate complete dentures. The objective of this in vitro investigation was to assess and contrast the color stability and dimensional accuracy of denture base resins that were 3D printed and CAD-CAM milled, both before and after aging by thermocycling using digital surface matching technology and a benchtop laser scanner without using a spray, to optimize adaptation of the denture base and cast to minimize any imperfections and to evaluate the impact of the denture cleansing solution on the stability of color.MethodsEvaluation of the dimensional accuracy (n = 27) was completed on a sectional maxillary stone cast using a digital 3D-surface matching software before and after 5000 thermocycles. A spectrophotometer was used to measure the color change (△E00) of all disc specimens (N = 54) before and after 500 thermocycles and immersion in denture cleansing solution for 30 cycles (3 min each) daily for 6 days. The Kruskal Wallis test, Dunn’s post hoc test, Tukey’s test with Bonferroni adjustment, one sample t test and independent t test were used to statistically analyze the data (α < 0.05).ResultsThermocycling decreased the dimensional accuracy of the heat polymerized group at all 5 locations and the 3D-printed group at locations 1, 3 and 5 (P > .05), while it had no significant difference on the CAD-CAM milled group at all locations (P < .05). The color change (△E00) was lowest in the CAD-CAM milled group, moderate in the heat-polymerized group and highest in the 3D-printed group. After immersion in denture cleanser, the color change (△E00) was significantly higher in the 3 groups compared with after thermocycling (P > .001).ConclusionsCAD-CAM milled resins had the highest dimensional accuracy and the best color stability, conventional heat polymerized acrylic resins showed moderate change in dimensional accuracy and color stability, while the 3D- printed resin had the lowest dimensional accuracy and color stability after aging by thermocycling.

Enhancing energy storage performance of dielectric capacitors: Tailoring CaO-SrO-Na2O-Nb2O5-SiO2 glass-ceramics through controlled crystallization for pulse power applications

As potential dielectric materials for capacitors, glass-ceramics exhibit significant promise in the realm of pulse power supply. Extensive research has been undertaken to explore the commendable voltage resistance and favorable dielectric properties of glass-ceramics. They exhibit a rapid charge and discharge rate. However, the limited energy storage density of glass-ceramics constrains their practical application. In this study, we focused on the preparation of CaO-SrO-Na2O-Nb2O5-SiO2(CSNNS) glass-ceramics through conventional melting and high-temperature crystallization processes. Our investigation delved into the impact of crystallization temperature on the phase composition, dielectric properties, and energy storage characteristics of the CSNNS glass-ceramics. The results indicate a direct correlation between the dielectric constant and dielectric loss, both exhibiting an upward trend with increasing crystallization temperature. Simultaneously, the microstructure of the glass-ceramics manifests signs of deterioration, characterized by larger grain size and heightened porosity, leading to a reduction in breakdown strength. At a crystallization temperature of 1100 °C, the CSNNS glass-ceramics demonstrated a remarkable combination of a high dielectric constant (∼280) and superior breakdown strength (481 kV/cm). The achieved maximum theoretical energy storage density reached 2.87 J/cm3. At an electric field of 100 kV/cm, the effective energy storage density is 0.23 J/cm3, and the energy storage efficiency is 72 %. These findings demonstrate the broad application potential of the CSNNS glass-ceramics in the domain of pulse power, highlighting their relevance for future developments in this field.