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Investigation of the performance and life cycle assessment of alkali-activated sintered sludge-slag-based permeable concrete

As urbanization continues to accelerate, the application of permeable concrete is becoming an increasingly prevalent practice. Nevertheless, the carbon dioxide emission issue associated with traditional permeable concrete cannot be overlooked. In this study, alkali-activated sintered sludge and slag were employed as raw materials to prepare alkali-activated sintered sludge-slag-based permeable concrete. The effects of sludge calcination temperature, sludge content, and binder-to-aggregate ratio on the compressive strength, porosity, and permeability coefficient of the permeable concrete were investigated through the implementation of one-way experiments. The formation mechanism of permeable concrete materials was analyzed using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and a carbon emission assessment was performed. The findings indicated that an increase in sludge content resulted in a notable decline in the 28-day compressive strength, accompanied by a reduction in the Ca/Si ratio of the C-A-S-H hydration products, from 1.08 to 0.35. Conversely, the carbon emission assessment demonstrated that abiotic losses declined markedly with an increase in sludge content, effectively mitigating the carbon emission burden associated with construction materials.

Preparation and Properties of Translucent Suspension Chain Polyurethane With a Broad Damping Temperature Range at Near Room Temperature

ABSTRACTDeveloping a viscoelastic polymer damping material with a broad range of effective damping temperatures at room temperature and multiple functionalities has been a prominent research focus, possessing significant economic and social importance. Herein, the elastic main chain was synthesized using branched polyester polyol (DPH) and isophorone diisocyanate (IPDI). The suspension chain prepolymer was fabricated with monohydroxy long alkyl‐chain hydroxy silicone oil (OH‐PDMS) and IPDI. Translucent and damping branched polyurethane viscoelastic materials (BPUs) were prepared by reacting the elastic main chain and the suspension chain prepolymer with the cross‐linking agent trimethylolpropane (TMP). The influences of introducing suspension chains and their content within the polyurethane structure on the damping, mechanical, dynamic mechanical, thermomechanical, and water resistance properties of the polyurethane were comprehensively investigated. The experimental results indicate that the damping factor (Tanδmax) of polyurethane decreases from 1.17 to 0.91 with the addition of suspension chain. Then, with the increase of suspension chain content, the damping factor (Tanδmax) decreases slightly. The damping factor (Tanδmax) still reaches 0.84 with 66% suspension chain content. At the same time, the effective damping temperature range gradually increases from 56.4°C to 119.4°C. The glass transition temperature decreased from 58.9°C to 27.8°C, enhancing the damping performance at room temperature. It was discovered that introducing suspension chains with the SiOSi structure would delay the decomposition of soft segments and enhance heat resistance. Additionally, when the content of the suspension chain is raised to 66%, the hydrophobicity of polyurethane reaches the maximum level and the elongation at break attains 423% ± 12%.

Study on the microstructure and mechanical properties of Fe35Co14Ni17Cr15Nb19 and Fe33Co14Ni15Cr12Nb26 high-entropy alloy coatings prepared by TIG

In this paper, two groups of high-entropy alloy coatings, Fe35Co14Ni17Cr15Nb19 and Fe33Co14Ni15Cr12Nb26, were prepared on a 304 stainless steel substrate using TIG. Both groups of coatings are composed of FCC + Laves phase and the Laves phase increases with the increase of Nb element content. In the Nb29 coating, a transition from sub-eutectic to fully eutectic structure occurs from the bottom to the top. The average microhardness of the two groups of high-entropy alloy coatings was 508.56 HV0.5 and 617.64 HV0.5, respectively, which was increased by 2.3 and 2.8 times compared with the substrate. The two groups of high-entropy alloy coatings were superior to the 304 substrate in wear and corrosion resistance, and the Nb26 coating had the best performance.

High internal phase Pickering emulsions stabilized by walnut protein–galactooligosaccharide nanoparticles: effect of cinnamon oil entrapment

Abstract Walnut protein–galactooligosaccharide (WalPI–GOS) nanoparticles were used to prepare high internal phase Pickering emulsions (HIPPEs). The entrapment properties of HIPPEs for cinnamon oil were investigated by varying the ratios of camellia and cinnamon oils (cinnamon oil contents: 0%, 2.5%, 5.0%, 10%, 15%, and 20%), and the droplet size, rheological properties, Raman spectroscopy results, microstructure, thermal stability, storage stability, and antioxidant activity of HIPPEs were determined. Results showed that the droplet size of HIPPEs increased with increasing cinnamon oil content. Among samples, HIPPEs with the cinnamon oil content of 10% had the highest storage and loss moduli and apparent viscosity (13.64 Pa·s). However, the thixotropic recovery ability of HIPPEs decreased with the increase in cinnamon oil content. Raman spectroscopy and microstructural analysis revealed that proteins covalently cross-linked with cinnamaldehyde to form a three-dimensional network structure, which showed the highest stability when the cinnamon oil content was 10%. HIPPEs exhibited high thermal stability without delamination after heating, as well as good storage stability without delamination or discoloration after 15 days of storage at 25 °C and 50 °C. Among samples, HIPPEs with 10% cinnamon oil content had the lowest POV and MDA values during storage. The addition of cinnamon oil significantly enhanced the antioxidant activity of HIPPEs. In summary, the best overall performance of HIPPEs was achieved at a cinnamon oil content of 10%. This result provides a theoretical foundation for the development of WalPI and the application of cinnamon oil in food, as well as a theoretical basis for the development of novel food delivery systems.

Polyurethane Nanocomposites with Open-Cell Structure Modified with Aluminosilicate Nano-Filler.

Nanocomposite flexible polyurethane foams (nFPUfs) were obtained by modifying the polyurethane formulation by adding a halloysite nano-filler in the amount of one to five parts by weight per hundred parts of used polyol (php). Flexible polyurethane (PU) foams with an open-cell structure and with a beneficial SAG factor were obtained. Premixes with nano-filler had a lower reactivity than the reference PU system. This favored the production of smaller cells, but with a more rounded shape in comparison with the REF foam without the nano-filler. During the study, the morphology and physical and mechanical properties were characterized, including apparent density, compressive stress, rebound flexibility, SAG factor, closed-cell content, and thermal stability, and compared with the properties of the unmodified reference foam. Scanning electron microscopy (SEM) showed that the cell structures of all prepared foams were open, and the cell size decreased with increasing nano-filler content. Apparent densities, SAG factors and rebound flexibilities of the foams increased with the increase of nano-filler content, while the resistance to permanent deformation showed the opposite trend. The proper selection of raw materials and optimally developed polyurethane formulations allow for obtaining environmentally friendly foams with favorable functional properties, taking into account price and the needs of sustainable development in the synthesis of flexible foams dedicated to the upholstery industry.

Experimental Investigation on the Permeability and Fine Particle Migration of Debris-Flow Deposits with Discontinuous Gradation: Implications for the Sustainable Development of Debris-Flow Fans in Jiangjia Ravine, China

The particle size distribution (PSD) is a crucial parameter used to characterize the material composition of debris-flow deposits which determines their hydraulic permeability, affecting the mobility of debris flows and, hence, the sustainable development of debris-flow fans. Three types of graded bedding structures—normal, reverse, and mixed graded bedding structures—are characterized by discontinuous gradation within a specific deposit thickness. A series of permeability tests were conducted to study the effects of bed sediment composition, particularly coarse grain sizes and fine particle contents, on the permeability and migration of fine particles in discontinuous debris-flow deposits. An increase in fine particles within the discontinuously graded bed sediment led to a power-law decrease in the average permeability coefficient. With fine particle contents of 10% and 15% in the bed sediments, the final permeability coefficient consistently exceeded the initial value. However, this trend reversed when the fine particle contents were increased to 20%, 25%, and 30%. Lower fine particle contents indicated enhanced permeability efficiency due to more interconnected voids within the coarse particle skeleton. Conversely, an increase in fine particle content reduced the permeability efficiency, as fine particles tended to aggregate at the lower section of the seepage channel. An increase in coarse particle size decreased the formation of flow channels at the coarse–fine particle interface, causing fine particles to move slowly along adjacent or clustered slow flow channels formed by fine particles, resulting in decreased permeability efficiency. Three formulae are proposed to calculate the permeability coefficients of discontinuously graded bed sediments, which may aid in understanding the initiation mechanism of channel deposits. Based on experimental studies and field investigations, it is proposed that achieving sustainable development of debris-flow fans requires a practical approach that integrates three key components: spatial land-use planning, in situ monitoring of debris flows and the environment, and land-use adjustment and management. This comprehensive and integrated approach is essential for effectively managing and mitigating the risks associated with debris flows, ensuring sustainable development in vulnerable areas.

Melting simulations of high-entropy carbonitrides by deep learning potentials

The melting temperature is a crucial property of materials that determines their potential applications in different industrial fields. In this study, we used a deep neural network potential to describe the structure of high-entropy (TiZrTaHfNb)CxN1−x carbonitrides (HECN) in both solid and liquid states. This approach allows us to predict heating and cooling temperatures depending on the nitrogen content to determine the melting temperature and analyze structure changes from atomistic point of view. A steady increase in nitrogen content leads to increasing melting temperature, with a maximum approaching for 25% of nitrogen in the HECN. A careful analysis of pair correlations, together with calculations of entropy in the considered liquid phases of HECNs allows us to explain the origin of the nonlinear enhancement of the melting temperature with increasing nitrogen content. The maximum melting temperature of 3580 ± 30 K belongs to (TiZrTaHfNb)C0.75N0.25 composition. The improved melting behavior of high-entropy compounds by the addition of nitrogen provides a promising way towards modification of thermal properties of functional and constructional materials.

The Information Content of Earnings: The Effects of a Change in Accounting Approach

ABSTRACTThis study leverages the adoption of ASC 606, “Revenue from Contracts with Customers,” to examine the effects of transitioning from a rules‐based to a principles‐based approach on the information content of earnings along with two of its most important attributes: predictive value and asymmetry. By introducing a common principles‐based framework, ASC 606 resolves inconsistencies found in earlier rules‐based standards and fosters uniformity in financial reporting. However, this change might also diminish the uniqueness of financial information, a critical factor in the decision‐making process. The findings reveal a significant increase in the overall market's information content of earnings post‐ASC 606 implementation. Industries with complex revenue recognition processes and long‐term contracts, such as information technology, real estate, and communications, experienced the most significant improvements. These industries benefited from the increased flexibility and professional judgment allowed under ASC 606, resulting in more accurate future earnings forecasts. However, the study also finds that ASC 606 has increased information asymmetry, particularly in industries with complex transactions. This suggests that while the principles‐based approach enhances the informativeness and predictive value of earnings, it also introduces challenges in interpreting and applying the new standards, leading to increased information asymmetry. These findings have important implications for standard setters, regulators, and practitioners in financial reporting.

Analyzing the Effect of Germination on Nutritional Characteristics of Kodo Millet Flour and Its Role in Rusk Development

Millets, the underutilized groups of cereal grains are considered as rich source of energy, carbohydrate and protein. Due to the presence of vitamins, minerals, essential fatty acids, phytochemicals and antioxidants that can help to eradicate several nutritional deficiency diseases, they are now termed as ‘nutri-cereals’ They contain appreciable quantities of phytochemicals such as phenolic acids, flavonoids, catechins, phytic acid and phytosterols. Owing to their important contribution in food security and potential health benefits, millet grains are now main topic of research for food scientists. This study thus aimed to develop kodo millet flour (KMF) via varying germination time (0h, 24h, 48h, and 72h) of kodo millet and preparing a bakery product (rusk) using the optimized KMF at varying concentrations of 0, 20, 30 and 50%. The germinated KMF were subjected to physiological studies, namely germination loss and germination efficiency. Optimum germination time was observed to be 48 h due to its high germination efficiency and a significantly lower germination loss as compared to 72 h of germination. Proximate analysis of KMF helped determine the increase in protein and fibre content of the germinated flour and a decreased ash, fat and moisture content. The significant changes (p ≤ 0.05) observed in all the analyses, helped determine the effect of different germination periods on various properties of dehusked kodo millet, and further optimize a particular germination time for better quality flour which would be used to form rusk. The results of this study thus suggested that germination of kodo millet could be effectively used to prepare kodo millet flour and further use it to prepare various baked products having good consumer acceptability.

Soil organic matter interactions along the elevation gradient of the James Ross Island (Antarctica)

Abstract. Around half of the Earth's soil organic carbon (SOC) is presently stored in the Northern Hemisphere permafrost region. In polar permafrost regions, low temperatures particularly inhibit both the production and biodegradation of organic matter. Under such conditions, abiotic factors such as mesoclimate, pedogenic substrate or altitude are thought to be more important for soil development than biological factors. In Antarctica, biological factors are generally underestimated in soil development due to the rare occurrence of higher plants and the short time since deglaciation. In this study, we aim to assess the relationship between SOC and other soil properties related to the pedogenic factors or properties. Nine plots were investigated along the altitudinal gradient from 10 to 320 m in the deglaciated area of James Ross Island (Ulu Peninsula) using a parallel tea-bag decomposition experiment. SOC contents showed a positive correlation with the content of easily extractable glomalin-related soil protein (EE-GRSP; Spearman r=0.733, P=0.031) and the soil buffering capacity (expressed as ΔpH; Spearman r=0.817, P=0.011). The soil-available P was negatively correlated with altitude (Spearman r=-0.711, P=0.032), and the exchangeable Mg was negatively correlated with the rock fragment content (Spearman r=-0.683, P=0.050). No correlation was found between the available mineral nutrients (P, K, Ca and Mg) and SOC or GRSP. This may be a consequence of the inhibition of biologically mediated nutrient cycling in the soil. Therefore, the main factor influencing nutrient availability in these soils does not seem to the biotic environment; rather, the main impact appears to stem from the abiotic environment influencing the mesoclimate (altitude) or the level of weathering (rock content). Incubation in tea bags for 45 d resulted in the consumption and translocation of more labile polyphenolic and water-extractable organic matter, along with changes in the C content (increase of up to +0.53 % or decrease of up to −1.31 % C) and a decrease in the C:N ratio (from 12.5 to 7.1–10.2), probably due to microbial respiration and an increase in the abundance of nitrogen-binding microorganisms. Our findings suggest that one of the main variables influencing the SOC/GRSP content is not the altitude or coarse-fraction content (for which a correlation with SOC/GRSP was not found); rather, we suspect effects from other factors that are difficult to quantify, such as the availability of liquid water.

Numerical Investigation of Combustion and Emission Characteristics of the Single-Cylinder Diesel Engine Fueled with Diesel-Ammonia Mixture

This study proposes a dual-fuel approach combining diesel and ammonia in a single-cylinder compression ignition engine to reduce harmful emissions from internal combustion. Diesel is directly injected into the combustion chamber, while ammonia is introduced through the intake manifold with intake air. In this study, injection timing and the percentage of ammonia energy fraction was varied. A computational fluid dynamics (CFD) model simulates the combustion and emission processes to assess the impact of varying diesel injection timings and ammonia energy contributions. Findings indicate that as ammonia content increases, the engine experiences reductions in peak in-cylinder pressure, temperature, heat release rate, as well as overall efficiency and power output. Emission results suggest that greater ammonia usage leads to a reduction in soot, carbon monoxide, carbon dioxide, and unburned hydrocarbons, though a slight increase in nitrogen oxides emissions is observed. This analysis supports ammonia’s potential as a low-emission alternative fuel in future compression ignition engines.

Investigation of Methane Adsorption and Diffusion Behavior in Hydrogen Sulfide-Containing Coal Seams.

This study aimed to investigate the methane adsorption-diffusion problem in coal seams containing hydrogen sulfide. Molecular simulations and Materials Studio software were used to study the difference in behavior between hydrogen sulfide and methane adsorption, as well as the effect of hydrogen sulfide on methane adsorption-diffusion behavior in coal seams. Comprehensive data were obtained on the influence of hydrogen sulfide on methane's adsorption amount, probability density distribution, interaction energy, and diffusion coefficient during the adsorption. The results showed that as the hydrogen sulfide content increased from 0 to 1.9%, porosity decreased from 14.41% to 11.25%, representing a 21.93% reduction. When methane and hydrogen sulfide were adsorbed in the coal seam, the adsorption amount of hydrogen sulfide was notably higher, with an adsorption heat of 38.25 kJ/mol, which is 24.65 kJ/mol greater than that for methane. An increase in the hydrogen sulfide content caused several adverse effects, including a decrease in methane's adsorption amount, Langmuir adsorption constant, and number of available adsorption sites within bituminous coal. Furthermore, the interaction energy and diffusion coefficient of methane molecules diminished during adsorption.

Composition of Breast Milk in Women with Obesity.

Background/Objectives: Among US breastfeeding women, those with obesity have significantly increased breast milk fat and caloric content from foremilk to hindmilk, with a 4-fold increase in fat content from the first to last milk sample. In view of different dietary norms and nutritional standards, we sought to evaluate the relationship between maternal BMI with breast milk fat and calorie content in women from Brazil, a low-middle-income country. Methods: Women who delivered singleton-term neonates were recruited from the Ana Abrao Breastfeeding Center (AABC) and Human Milk Bank at the Federal University of Sao Paulo, Brazil. These women were then studied at 7-8 weeks postpartum. Women were grouped by BMI categories of nonobese (NonOB; BMI 18.5-29.9) and obese (OB; BMI ≥ 30). A breast pump was applied, and milk samples were obtained continuously in 10 mL aliquots from foremilk to hindmilk; samples were analyzed for macronutrients and lipids, and maternal blood was analyzed for serum lipids and glucose. Results: As compared to NonOB women, those with OB had significantly higher milk fat in the mid (4.9 ± 0.3 vs. 3.9 ± 0.2) and last hindmilk (6.6 ± 0.4 vs. 5.5 ± 0.3) samples, though not in the first foremilk sample, as compared to NonOB women. In both NonOB and OB subjects, milk caloric and fat content increased 1.5 to 2-fold from foremilk to hindmilk, with the average milk caloric value being 11% greater in OB women. Protein content was significantly increased in all three milk samples (first, middle, and last) in women with OB. Conclusions: Although the value of breastfeeding remains clear, these findings may have significant implications for infant nutrition and excessive infant weight gain in women with OB.

Insight into the Mechanical Properties and Microstructure of Recycled Aggregate Concrete Containing Carbon Fibers and Nano-SiO2.

This study aimed to improve the mechanical properties and microstructure of recycled aggregate concrete (RAC) by incorporating carbon fibers (CFs) and nano-SiO2 (NS) to promote the optimal utilization of RAC. The mechanical properties of the RAC were enhanced by both single and hybrid additions of CFs and NS, and the hybrid addition had a better strengthening effect. From the experimental results, it was found that the addition of CFs could increase the 28 d compressive strength and splitting strength of the RAC by 9.05% and 22.36%, respectively. The hybrid CFs and NS were more conducive to improving the mechanical properties of the RAC, and the enhancement effect increased first and then decreased with an increase in the NS content. The optimal content of NS was 0.8 wt%, which increased the 28 d compressive strength and splitting strength of the RAC by 20.51% and 14.53%, respectively. The microstructure results indicated that the addition of CFs had little effect on the optimized pore structure of the RAC, but the crack inhibition action of the CFs could improve the mechanical properties of the RAC. The addition of NS reduced the content of CH and facilitated the formation of more (C-S-H) gel. The hydrated calcium silicate (C-S-H) gel significantly decreased the porosity and transformed harmful capillary pores and harmful pores into harmless capillary pores and gel pores, thus improving the mechanical properties of the RAC. Therefore, the use of hybrid CFs and NS was more conducive to enhancing the performance of RAC for building materials.

Diacerein ameliorates thioacetamide-induced hepatic encephalopathy in rats via modulation of TLR4/AQP4/MMP-9 axis

Astrocyte swelling, blood brain barrier (BBB) dissipation and the subsequent brain edema are serious consequences of persistent hyperammonemia in hepatic encephalopathy (HE) in which if inadequately controlled it will lead to brain death. The current study highlights the potential neuroprotective effect of diacerein against thioacetamide (TAA)-induced HE in acute liver failure rat model. HE was induced in male Sprague–Dawley rats via I.P. injection of TAA (200 mg/kg) for three alternative times/week at 3rd week of the experiment. Diacerein (50 mg/kg) was gavaged for 14 days prior to induction of HE and for further 7 days together with TAA injection for an overall period of 21 days. Diacerein attenuated TAA-induced HE in acute liver failure rat model; as proofed by significant lowering of serum and brain ammonia concentrations, serum AST and ALT activities and significant attenuation of both brain and hepatic MDA contents and IL-1β with marked increases in GSH contents (P < 0.0001). The neuroprotective effect of diacerein was demonstrated by marked improvement of motor and cognitive deficits, brain histopathological changes; hallmarks of HE. As shown by immunohistochemical results, diacerein markedly downregulated brain TLR4 expression which in turn significantly increased the GFAP expression, and significantly decreased AQP4 expression; the astrocytes swelling biomarkers (P < 0.0001). Moreover, diacerein preserved BBB integrity via downregulation of MMP-9 mediated digestion of tight junction proteins such as occludin (P < 0.0001). Collectively, diacerein ameliorated cerebral edema and maintained BBB integrity via modulation of TLR4/AQP4/MMP-9 axis thus may decrease the progression of HE induced in acute liver failure.

Effect of CaO/SiO2 and Al2O3/SiO2 Mass Ratios on Structure and Viscosity of Mold Flux for Continuous Casting High‐Mn High‐Al Steel

During continuous casting process of high‐Mn high‐Al steel, soluble Al in the steel typically reacts with SiO2 in the mold flux, resulting in a decrease in SiO2 content and an increase in Al2O3 contents in the flux. The structure of slags with varying CaO/SiO2 and Al2O3/SiO2 mass ratio is investigated using Raman spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. In the deconvolution results of Raman and NMR spectra, it is shown that the relative fractions of and significantly increase, while and gradually decrease with an increase in the CaO/SiO2 mass ratio from 0.52 to 1.02, resulting in depolymerization of the bridge oxygen structure. The silicon–oxygen tetrahedron transforms into aluminum–oxygen tetrahedron when the Al2O3/SiO2 mass ratio increased from 0.05 to 1.01. The viscosity of the slags with varying composition from 1573 to 1373 K is investigated. In the results, it is shown that with an increase in the CaO/SiO2 mass ratio, the viscosity decreases, and the complex SiO network structure is depolymerized. The viscosity decreases first as the Al2O3/SiO2 mass ratio increases from 0.05 to 0.24 and then increases as the mass ratio from 0.24 to 1.01, with the network formers transfer from SiO to SiAlO structures.

Ensiling Characteristics, Bacterial Community Structure, Co-Occurrence Networks, and Their Predicted Functionality in Alfalfa Haylage Silage with or Without Foliar Selenium Application

Selenium (Se) is an essential trace element in living systems. In this study, we applied a spray of 50 mg/kg sodium selenite to alfalfa (Medicago sativa L.) at different stages of development (bud, initial bloom, and full bloom stages). After 0, 1, 3, 7, and 45 days of ensiling, we assessed the fermentation quality, chemical composition, and bacterial community of the alfalfa. Our findings indicated that the addition of Se led to an increase in the Se content and a decrease in the pH, acid detergent fiber (ADF), and neutral detergent fiber (NDF) contents. As ensiling fermentation progressed, the Se treatments increased the relative abundance of Lactobacillus, which was significantly greater than that in the control group (42.44% vs. 3.76%). In conclusion, the addition of sodium selenate to silage additive ensures the quality of the silage and reduces bacterial community diversity. This study provides valuable insights for the investigation of Se enrichment in alfalfa haylage silage.

Tensile Properties of Ex-Situ Ti-TiC Metal Matrix Composites Manufactured by Laser Powder Bed Fusion.

Titanium-based Metal Matrix Composites (MMCs) manufactured by additive manufacturing offer tremendous lightweighting opportunities. However, processing the high reinforcement contents needed to substantially improve elastic modulus while conserving significant ductility remains a challenge. Ti-TiC MMCs fabricated in this study reported fracture strains in tension up to 1.7% for a Young's modulus of 149 GPa. This fracture strain is 30% higher than the previously reported values for Ti-based MMCs produced by Laser Powder Bed Fusion (LPBF) displaying similar Young's moduli. The heat treatment used after the LPBF process leads to the doubling of the fracture strain thanks to the conversion of TiCx dendrites into equiaxed TiCx grains. The as-built microstructure shows both un-dissolved TiC particles and sub-stoichiometric TiC dendrites resulting from the partial dissolution of TiC particles. The reduction of the C/Ti ratio in TiC during the process results in an increase in the reinforcement content, from a nominal 12 vol% to an effective 21.5 vol%. The variation of the TiC lattice constant with its stoichiometry is measured, and an empirical expression is proposed for its effect on TiC's Young's modulus. The lower TiC powder size distribution displayed higher mechanical properties thanks to a reduced number of intrinsic flaws.

Effect of δ-Ferrite Formation and Self-Tempering Behavior on Mechanical Properties of Type 410 Martensitic Stainless Steel Fabricated via Laser Powder Bed Fusion.

This study explores the formation of δ-ferrite and its self-tempering behavior in the microstructure of Type 410 martensitic stainless steel produced via laser powder bed fusion (L-PBF). The study investigates the correlation between varying energy densities applied during the L-PBF process and the resultant mechanical properties of the as-built specimens. A microstructural analysis shows that with an increase in energy density, the δ-ferrite fraction decreases, while the martensite content increases, leading to changes in tensile strength and elongation. Higher energy densities reduce tensile strength but significantly enhance ductility. The self-tempering effect of martensite in reheated zones, caused by the complex thermal cycling during the L-PBF process, plays a critical role in determining mechanical behavior. These findings provide valuable insights for optimizing the additive manufacturing of martensitic stainless steels to achieve the desired mechanical properties.

Aborted oceanic basin during the Mesozoic rifting of the South-Iberian Palaeomargin and interactions with the sedimentation processes

ABSTRACT During the Mesozoic, the South-Iberian Palaeomargin experienced successive phases of extensional tectonics related to the fragmentation of Pangea and the aperture of the Central Atlantic. During the Pliensbachian, the rifting favoured the fracturing and collapse of the Early Jurassic carbonate platform and delimited a subdomain characterized by high subsidence called Median Subbetic (Betic Cordillera, S Spain). The progression of the rifting and the related extension along ~ 102 Ma, from late Pliensbachian to Santonian, favoured the activity of lithospheric scale faulting and extensional basic magmatism in the Median Subbetic with alkaline affinity. The highest volume of lava emissions, represented by pillow-lava flows interbedded with hemipelagic sediments, occurred during the Middle Jurassic. The pillow-lavas show aphanitic texture with Ca-rich plagioclase and clinopyroxene, whereas subvolcanic rocks are aphanitic with high content of plagioclase to phaneritic with plagioclase, olivine and biotite. The rocks present low SiO2 (46.6–53.5 wt.%) and relatively high K2O (locally reaching 8.7 wt.%), and the content of trace elements generally ranges between those from E-MORB and OIB composition. Values of some ratios such as (Gd/Yb)N, (La/Yb)N, (La/Sm)N, and the Nb content increase in the Upper Cretaceous pillow-lava flows, whereas Yb and Y contents decrease, that point to more alkaline affinity. Low Yb and Y contents point to the presence of garnet as residual phase in the mantle source. We interpret that during the early Late Cretaceous, hyperextensional phase of the continental rifting throughout an aborted oceanic basin occurred and allowed lithospheric deeper asthenospheric mantle up-lift and the partial melting. The phases of extensional tectonic controlled the configuration of this palaeomargin in complex tectono-palaeogeographic subdomains, the sedimentary cycles, and the volcanic activity during the Jurassic and Cretaceous. Finally, the transition from passive margin to a convergent one began during the Campanian and no more volcanism is recorded in the Median Subbetic.