Similar Density Research Articles

Comparison of the neutronic properties of the (Th-233U)O2, (Th-233U)C, and (Th-233U)N fuels in small long-life PWR cores with 300, 400, and 500 MWth of power

Abstract The neutronic characteristics of (Th-233U)O2, (Th-233U)C, and (Th-233U)N have been compared in small long-life pressurized water reactors (PWRs). Neutronic calculations were carried out at 300 MWth, 400 MWth, and 500 MWth with two cladding types: zircaloy-4 and ZIRLO (Zr low oxygen). They were performed using the Standard Reactor Analysis Code (SRAC) and JENDL-4.0 nuclide data, dividing the reactor core into three fuel zones with varying 233U enrichment levels, ranging from 3% to 9% and fluctuating by 1%, employing the PIJ module at the fuel cell level and the CITATION module at the reactor core level. In addition, 231Pa was added as burnable poison (BP). The (Th-233U)N fuel demonstrated superior criticality compared to the other fuel types, as it consistently achieves critical conditions throughout the reactor’s operating cycle with excess reactivity <1.00% dk/k for several fuel configurations at the 300 MWth and 400 MWth power levels. Moreover, the (Th-233U)N and (Th-233U)C fuels exhibited similar and flatter power density distribution patterns compared to the (Th-233U)O2 fuel. The power peaking factor (PPF) value was relatively higher for (Th-233U)O2 fuel than the other two fuels. The (Th-233U)N fuel exhibited the most negative Doppler coefficient, followed by (Th-233U)C and (Th-233U)O2 fuels. Analysis of burnup levels revealed that the (Th-233U)O2 fuel achieved significantly higher burnup than the other two fuels.

Density of smooth functions in Musielak–Orlicz–Sobolev spaces Wk,Φ(Ω)$W^{k,\Phi }(\Omega)$

AbstractWe consider here Musielak–Orlicz–Sobolev (MOS) spaces , where is an open subset of , and is a Musielak–Orlicz function. The main outcomes consist of the results on density of the space of compactly supported smooth functions in . One section is devoted to compare the various conditions on appearing in the literature in the context of maximal operator and density theorems in MOS spaces. The assumptions on we apply here are substantially weaker than in the earlier papers on the topics of approximation by smooth functions. One of the reasons is that in the process of proving density theorems, we do not use the fact that the Hardy–Littlewood maximal operator on Musielak–Orlicz space is bounded, a standard tool employed in density results for different types of Sobolev spaces. We show in particular that under some regularity assumptions on , (A1) and that are not sufficient for the maximal operator to be bounded, the space of is dense in . In the case of variable exponent Sobolev space , we obtain the similar density result under the assumption that , , , , satisfies the log‐Hölder condition and the exponent function is essentially bounded.

Effects of Waste Plastic and Glass Aggregates on the Strength Properties of Ambient-Cured One-Part Metakaolin-Based Geopolymer Concrete

The production of Portland cement (PC) is associated with carbon emissions. One-part geopolymer “just add water” is a user- and environmentally-friendly binder that can potentially substitute PC. However, there is limited research on the setting time, fresh, and strength properties of one-part metakaolin (MK)-based geopolymer concrete (OMGPC) incorporating recycled aggregates. Hence, the study explored the fresh, mechanical (compressive, flexural, splitting tensile, and E-modulus) and microstructural properties of ambient cured (7-, 28-, and 90-day) OMGPC containing recycled waste plastics (RESIN8) and recycled fine waste glass aggregate (FWG) at 5% and 10% by volume of the sand. The study result shows that 2% trisodium phosphate by wt. of the binder retard the initial and final setting times of OMGPC. At the same time, the incorporation of RESIN8 and FWG aggregates improved the workability of geopolymer concrete. The lightweight properties of RESIN8 aggregate reduce the hardened density of OMGPC, while the FWG specimens show a similar density to the control. The compressive strength of RESIN8 and FWG OMGPC range from 19.8 to 24.6 MPa and 26.9 to 30 MPa, respectively, compared to the control (26 to 28.9 MPa) at all curing ages. The flexural and splitting tensile strength of the OMGPC range from 2.2 to 4.5 MPa and 1.7 to 2.8 MPa, respectively. OMGPC is a viable alternative to Portland cement, and FWG can substitute sand in structural concrete by up to 10% and RESIN8 aggregate at 5% by volume of the natural sand.

A continuum of amorphous ices between low-density and high-density amorphous ice

Amorphous ices are usually classified as belonging to low-density or high-density amorphous ice (LDA and HDA) with densities ρLDA ≈ 0.94 g/cm3 and ρHDA ≈ 1.15−1.17 g/cm3. However, a recent experiment crushing hexagonal ice (ball-milling) produced a medium-density amorphous ice (MDA, ρMDA ≈ 1.06 g/cm3) adding complexity to our understanding of amorphous ice and the phase diagram of supercooled water. Motivated by the discovery of MDA, we perform computer simulations where amorphous ices are produced by isobaric cooling and isothermal compression/decompression. Our results show that, depending on the pressure employed, isobaric cooling can generate a continuum of amorphous ices with densities that expand in between those of LDA and HDA (briefly, intermediate amorphous ices, IA). In particular, the IA generated at P ≈ 125 MPa has a remarkably similar density and average structure as MDA, implying that MDA is not unique. Using the potential energy landscape formalism, we provide an intuitive qualitative understanding of the nature of LDA, HDA, and the IA generated at different pressures. In this view, LDA and HDA occupy specific and well-separated regions of the PEL; the IA prepared at P = 125 MPa is located in the intermediate region of the PEL that separates LDA and HDA.

The morphological mix of dwarf galaxies in the nearby Universe

ABSTRACT We use a complete, unbiased sample of 257 dwarf (10$^{8}\, {\rm M}_{\odot } \lt M_{\rm {\star }} \lt 10^{9.5}\, {\rm M}_{\odot }$) galaxies at z < 0.08, in the COSMOS field, to study the morphological mix of the dwarf population in low-density environments. Visual inspection of extremely deep optical images and their unsharp-masked counterparts reveals three principal dwarf morphological classes. 43 per cent and 45 per cent of dwarfs exhibit the traditional ‘early-type’ (elliptical/S0) and ‘late-type’ (spiral) morphologies, respectively. However, 10 per cent populate a ‘featureless’ class, that lacks both the central light concentration seen in early-types and any spiral structure – this class is missing in the massive-galaxy regime. 14 per cent, 27 per cent, and 19 per cent of early-type, late-type, and featureless dwarfs respectively show evidence for interactions, which drive around 20 per cent of the overall star formation activity in the dwarf population. Compared to their massive counterparts, dwarf early-types show a much lower incidence of interactions, are significantly less concentrated and share similar rest-frame colours as dwarf late-types. This suggests that the formation histories of dwarf and massive early-types are different, with dwarf early-types being shaped less by interactions and more by secular processes. The lack of large groups or clusters in COSMOS at z < 0.08, and the fact that our dwarf morphological classes show similar local density, suggests that featureless dwarfs in low-density environments are created via internal baryonic feedback, rather than by environmental processes. Finally, while interacting dwarfs can be identified using the asymmetry parameter, it is challenging to cleanly separate early and late-type dwarfs using traditional morphological parameters, such as ‘CAS’, M20, and the Gini coefficient (unlike in the massive-galaxy regime).

Ceramic coating on Mg alloy for enhanced degradation resistance as implant material

Magnesium (Mg) alloys display very appealing characteristics, including biocompatibility, bioactivity, biodegradability, lightweightness, and a similar density to cortical bone tissue, but they have some constraints, such as inappropriate corrosion and degradation resistance, which lead to failing early mechanical strength. Therefore, calcium phosphate (CaP)-based ceramic coating like hydroxyapatite (HA) coating is fabricated on the anodization-induced surfaces of pure Mg and ZK41 Mg alloy specimens to overcome those constraints in medical applications. In mechanical integrity like microhardness, adhesion strength tests demonstrated that HA coated ZK41 and Mg specimens significantly increased Vickers' hardness number (about 2 times) compared to unmodified substrates and had greater adhesion strength in comparison with the anodization-induced layer, respectively. In the in vitro immersion test, the HA-coated samples showed plate-like and needle-like crystal formations. This provided more surface area, which improved the corrosion and degradation resistance characteristics. As a consequence, the least amount of weight loss has occurred.Additionally, the anodized (AN) Mg, HA coated Mg, untreated ZK41, and anodized ZK41 samples all have higher corrosion rates than the HA coated ZK41 (0.018 mm/year). Cell viability of HA coated Mg and its alloy ZK41 was comparatively high, which ensures biocompatibility as an implant material. Therefore, HA coatings for Mg and ZK41 alloys for clinical applications could be more promising. In this study, ZK41 Mg alloy has been used as an inventive substrate for HA coating in place of the prior Mg alloys, with the intention of addressing the earlier drawbacks.

A CFD study on the start-up hydrodynamics of fluid catalytic cracking regenerator integrated with chemical looping combustion

ABSTRACT The integration of chemical looping combustion with fluid catalytic cracking (CLC-FCC) is an innovative concept that serves as a cost-effective method for CO2 capture in refineries. This approach has the potential to reduce refinery CO2 emissions by 25–35%, offering a promising solution. As in the conventional FCC unit, it is common for CLC-FCC regenerators to be exposed to an on-off process while they are being maintained and cleaned. The novelty of this research lies in its specific focus on a less-explored phase (start-up) of CLC-FCC regenerators, the application of advanced CFD modeling, and the comprehensive analysis of operational parameters that influence the system’s performance. To validate the CFD simulations of the different drag models for solid-gas granular, bed density profiles under steady-state conditions, collected from industrial processes, were used. For the flow period based on the start-up process of the drag models, the fluidization gas inlet geometry of the regenerator, flow regime (laminar and turbulent), and superficial gas velocity were comprehensively investigated to reveal their effects on hydrodynamic characteristics. The results show that Gidaspow and Syamlal-O’Brien drag models of the solid-gas multiphase granular flow exhibited a better fit with industrial data. The Syamlal-O’Brien and Gidaspow models closely align with industrial data under steady-state conditions, displaying similar bed densities in the dense phase region (230–310 kg/m3 for Syamlal-O’Brien and 235–300 kg/m3 for Gidaspow). During the initial stage (less than 0.2 seconds), both laminar and turbulent models yield comparable bed density profiles, approximately 510 kg/m3 in the dense phase. However, as the process progresses, the dense phase density decreases to about 250–350 kg/m3 at around 0.5 seconds, with laminar flow models showing a slightly better fit with industrial data. Notably, at 0.5 seconds of fluidization time, inlet geometries having better gas distribution achieve a highly diluted phase with bed densities of 10–20 kg/m3. Reaching a steady state, the bed density decreases from around 400 kg/m3 to 260–300 kg/m3, expanding into a higher section of the regenerator where it aligns well with industrial data. The increase in superficial gas velocity would result in the clarification of the difference and well mixing of the solid-gas multiphase flow.

Application of alternative identification methods for live tularaemia and brucellosis vaccines

SCIENTIFIC RELEVANCE. The sanctions currently imposed on the Russian Federation requireusing Russian diagnostic products in vaccine quality assessments, as well as searching for alternative testing methods, in particular, serological ones.AIM. This study aimed to demonstrate the possibility of using alternative serological methods, including immunoenzymatic, direct agglutination, and indirect haemagglutination methods, for the identification of tularaemia and brucellosis vaccines in studies and quality assessments. MATERIALS AND METHODS. This study used the established pharmacopoeial reference standard (RS) for the bacterial suspension opacity of 10 international opacity units, the established pharmacopoeial RS for and two commercial batches of the live brucellosis vaccine (Brucella abortus 19 BA), and the established and candidate pharmacopoeial RSs for the live tularaemia vaccine (Francisella tularensis 15 NIIEG). These pharmacopoeial RSs were certified by the Scientific Centre for Expert Evaluation of Medicinal Products. Serological testing used Russian commercial diagnostic products, including dry diagnostic sera (polyvalent brucellosis and tularaemia sera for agglutination tests), a liquid erythrocytic diagnostic preparation of tularaemia immunoglobulin, and enzyme immunoassay (ELISA) diagnostic kits for detecting the causative agents for brucellosis and tularaemia. Statistical analysis involved using Microsoft Excel (P=0.95) for ELISA results and qualitative evaluation for the results of direct agglutination and indirect haemagglutination tests.RESULTS. All the tested batches demonstrated positive results. Live brucellosis vaccine batches showed positive results in the slide agglutination tests, while live tularaemia vaccine batches yielded positive results in the tube agglutination tests. All indirect haemagglutination tests showed haemagglutination in live tularaemia vaccine samples at the same concentration as positive control samples (6.25×106 cells/mL). ELISA tests showed similar optical density values (D)for the two vaccines and positive control samples. Live tularaemia and brucellosis vaccines (undiluted, 1.0×109 cells/mL) had D=2.133±0.273 and D=0.127±0.013, whereas the corresponding control samples had D=1.942±0.056 and D=0.123±0.007, respectively. The results reflected the presence of brucellosis or tularaemia microbes in the samples, confirming the identity of the vaccines.CONCLUSIONS. Serological immunoenzymatic, direct agglutination, and indirect haemagglu tination methods with Russian diagnostic products can be used to identify live brucellosis and tularaemia vaccines during quality assessment. The agglutination method with Russian diagnostic sera can be recommended as an alternative quality assessment method for the identification of live brucellosis and tularaemia vaccines, as this method offers time efficiency, simple visual evaluation of results, and low costs and relatively long shelf lives of diagnostic products. However, ELISA and indirect haemagglutination methods cannot be recommended for this purpose because of their labour-intensive and uneconomical nature. The results of this study may support the introduction of the agglutination method in the regulatory documents for live brucellosis and tularaemia vaccines (as an alternative method).

Location matters: spatial dynamics of tumor-infiltrating T cell subsets is prognostic in colon cancer.

Colon cancer is a heterogeneous disease and consists of various molecular subtypes. Despite advances in high-throughput expression profiling, limitations remain in predicting clinical outcome and assigning specific treatment to individual cases. Tumor-immune interactions play a critical role, with tumors that activate the immune system having better outcome for the patient. The localization of T cells within tumor epithelium, to enable direct contact, is essential for antitumor function, but bulk DNA/RNA sequencing data lacks spatial distribution information. In this study, we provide spatial T cell tumor distribution and connect these data with previously determined genomic data in the AC-ICAM colon cancer patient cohort. Colon cancer patients (n=90) with transcriptome data available were selected. We used a custom multiplex immunofluorescence assay on colon tumor tissue sections for quantifying T cell subsets spatial distribution in the tumor microenvironment, in terms of cell number, location, mutual distance, and distance to tumor cells. Statistical analyses included the previously determined Immunologic Constant of Rejection (ICR) transcriptome correlation and patient survival, revealing potential prognostic value in T cell spatial distribution. T cell phenotypes were characterized and CD3+CD8-FoxP3- T cells were found to be the predominant tumor-infiltrating subtype while CD3+FoxP3+ T cells and CD3+CD8+ T cells showed similar densities. Spatial distribution analysis elucidated that proliferative T cells, characterized by Ki67 expression, and Granzyme B-expressing T cells were predominantly located within the tumor epithelium. We demonstrated an increase in immune cell density and a decrease in the distance of CD3+CD8+ T cells to the nearest tumor cell, in the immune active, ICR High, immune subtypes. Higher densities of stromal CD3+FoxP3+ T cells showed enhanced survival outcomes, and patients exhibited superior clinical benefits when greater spatial distances were observed between CD3+CD8-FoxP3- or CD3+CD8+ T cells and CD3+FoxP3+ T cells. Our study's in-depth analysis of the spatial distribution and densities of major T cell subtypes within the tumor microenvironment has provided valuable information that paves the way for further research into the intricate relationships between immune cells and colon cancer development.

Short‐ and long‐term legacies of carbon sequestration, and nutrient burial in floodplain wetlands of agricultural and forested catchments, Indiana, United States

AbstractSoil organic carbon (C) sequestration and nitrogen (N) and phosphorus (P) burial were measured in two floodplain wetlands' soils of the West Fork of the White River watershed (Indiana, United States) whose catchments differed in land use to better understand how land use practices affect wetland C and nutrient retention. The catchment of one floodplain, Upper West Fork, is dominated by row crop agriculture (61%) whereas the second catchment, Beanblossom Creek, is mostly forested (85%). Soils (0–30 cm) of the two floodplain wetlands had similar bulk density (1.23 g/cm3). Soil organic C and N were low in both floodplains but the percent organic C and N was two times greater (3.3% C, 0.22% N) in the agricultural floodplain than in the floodplain in the forested catchment (1.5% C, 0.14% N). Soil P was three times greater in the agricultural (1100 μg/g) than in the forested floodplain (350 μg/g). Recent soil accretion based on 137Cs which provides a historical record since 1964 (60 years), was two times greater in the agricultural floodplain (2.2 mm/year) than in the forested catchment (1.0 mm/year). Sediment deposition (2500 g/m2/year), C sequestration (90 g/m2/year), and N burial (7.5 g/m2/year) were three times greater in the agricultural floodplain and P burial was seven times greater (3.0 vs. 0.41 g/m2/year). Long‐term measurements (100 years) based on 210Pb did not show large differences in C sequestration and N burial between the two floodplains though soil accretion and sediment deposition were greater in the forested floodplain. We attribute these higher rates to greater erosion in the watershed before 1950 when the catchment had more agricultural land and before instruction on best management practices to reduce soil erosion. These findings confirm previously published studies that show that P enrichment and accumulation in floodplain soils represent legacy effects of agricultural land use in the catchment.

Disentangling Multiple Emitting Components in Molecular Observations with Nonnegative Matrix Factorization

Molecular emission from the galactic and extragalactic interstellar medium (ISM) is often used to determine the physical conditions of the dense gas. However, even from spatially resolved regions, the observed molecules do not necessarily arise from a single component. Disentangling multiple gas components is often a degenerate problem in radiative transfer studies. In this paper, we investigate the use of the nonnegative matrix factorization (NMF) approach as a means to recover gas components from a set of blended line intensity maps of molecular transitions that may trace different physical conditions. We run a series of experiments on synthetic data sets designed to replicate conditions in two very different environments: galactic pre-stellar cores and the ISM in high-redshift galaxies. We find that the NMF algorithm often recovers the multiple components resembling those used in the data-generating process, provided that the different components have similar column densities. When NMF fails to recover all the individual components it does however group together the most similarly emitting ones. We further found that initialization and regularisation are key factors in the efficiency of the NMF algorithm.

Effect of high current pulsed electron beam on surface microstructure and properties of cold-rolled austenitic stainless steel

High current pulsed electron beam (HCPEB) was used to modify the surface microstructure and performance of AISI 304 stainless steel with different cold-rolling deformation. The phase, microstructure, microhardness, and corrosion performance were characterized and analyzed after cold-rolling and HCPEB treatment. The results show that after cold-rolling, deformation-induced martensites (DMs) are generated in the deformation twin lamellae or at the intersections of multiple twin lamellae, resulting in a grid-like morphology, smaller size, and a certain orientation relationship with the parent austenite. The content of DMs increases with increasing cold-rolling deformation. After HCPEB treatment, many craters with different sizes and similar densities are produced on the sample surface, and the DMs are transformed into austenite again in the surface layer. The difference is that the grain size of the regenerated austenite after HCPEB is much smaller than that of the initial austenite (before cold-rolling). Such high-density equiaxed ultrafine grains (UFGs) of austenite formed after HCPEB present a twin feature, which is the inheritance of the orientation relationship between DMs and austenite formed during rolling. HCPEB treatment can effectively reshape the phase and microstructure of the surface layer of the cold-rolled deformed austenitic steel but reduce the surface hardness and increase pitting corrosion tendency.

Experimental Analysis of Moisture-Dependent Thermal Conductivity, and Hygric Properties of Novel Hemp-shive Insulations with Numerical Assessment of Their In-Built Hygrothermal and Energy Performance.

The use of lime as a binder in hemp-lime considerably increases the drying time of hemp-lime after casting. Furthermore, lime is a non-renewable mineral resource. As such, this paper explores the effectiveness of using an alternative non-mineral binder instead of lime to formulate a novel hemp-shive insulation. The moisture-dependent thermal conductivity, adsorption isotherm, vapour diffusion resistance factor, and in-built hygrothermal performance of four variants of a novel bio-based insulation were investigated. The hygrothermal performance of the novel hemp-shive insulation was compared with that of a previously developed novel hemp-lime insulation. No significant variation in thermal conductivity of hemp-shive insulations between the equilibrium moisture contents (EMC) at 0% and 50% relative humidity (RH) was observed, but there was a substantial increase in thermal conductivity hemp-shive insulations when the material reached the EMC at 98% RH. The average dry thermal conductivity values of hemp-shive and hemp-lime insulations were also similar. The adsorption isotherms of hemp-shive insulations were determined at 0%, 20%, 50%, 70%, 90%, and 98% relative humidity steps. At 98% RH, the moisture adsorption capacity of hemp-shive insulations was 4-to-5-times higher than that of hemp-lime insulation. Hemp-shive insulations' vapour diffusion resistance factor (µ value) was about double the µ value of hemp-lime insulation. Hemp-shive insulations exhibited 4-to-5-times higher water absorption resistance than that of hemp-lime insulation. Numerically determined porosity values of hemp-shive agree with the values of wood-based insulation materials of similar density. Finally, using all experimentally acquired data as inputs, dynamic whole-building hygrothermal simulations were carried out and the results show that novel hemp-shive insulation materials perform at a similar level to the hemp-lime insulation in terms of heating and cooling energy demand but require 45% less energy for humidification. However, the relative humidity inside the hemp-shive wall remains higher than 70%, which can potentially induce mould growth.

The ecological value of fully enforced, no‐entry, marine protected areas: A case study of harvested limpets

Abstract Harvesting of intertidal gastropods can lead to a direct reduction in the biomass of targeted species through a reduction in the numbers and size of individuals, in turn leading to extensive changes to the structure of intertidal communities. In the Azores, two patellid species co‐occur, and both are exploited for human consumption. However, one of these species, Patella aspera (Röding, 1798), is larger and has a greater economic value and is thus favoured in comparison to the smaller Patella candei (d'Orbigny, 1840). This study investigates the effects of human exploitation on the interaction between these two species by comparing their densities and sizes within two areas of a marine protected area (MPA): a no‐entry area where human access is strictly prohibited and an adjacent area where human access is allowed and collection still occurs despite it being prohibited. Patella aspera attained similar densities in the two areas, but individuals were much larger within the no‐entry MPA. In contrast, P. candei were more abundant in the adjacent area but were of a similar size as in the no‐entry MPA. Limpet biomass was much greater within the no‐entry MPA. The abundance (% cover) of upright macroalgae and barnacles as well as bare rock were also significantly reduced within the no‐entry MPA, where grazer‐resistant algal crusts cover was significantly greater. This study highlights the influence of human activities and how these may affect the complex dynamics of biotic interactions with wider community‐level cascading effects.

Predicting Wood Density Using Resistance Drilling: The Effect of Instrument and Operator

The IML PD series Resi is an instrument designed to measure the drilling resistance of wood. Use of the IML PD series Resi instrument is rapidly becoming a routine method among Australian forest plantation growers for wood quality assessments. The major driver in the commercial uptake of the IML Resi is that it is fast, cheap, and sufficiently precise for commercial use, particularly when the data are processed through a user-friendly, web-based processor. This study examined whether the accuracy of wood density predictions was impacted by the use of different Resi tools and different operators, which has never been examined before. Seven Resi instruments were evaluated across six sites with two operators on plantation-grown Southern Pine (Pinus caribaea var. hondurensis (Sénéclauze) or hybrids between Pinus elliottii var. elliottii (Engelm) × P. caribaea var. hondurensis) trees. Two types of Resi instruments were used (IML Resi PD-400 and IML Resi PD-500), and all had been recently serviced or were new. The instruments were operated by experienced operators. Constant sampling conditions of feed speed 200 cm/min and 3500 RPM were used. The order of instrument use, and hence the order of operator assessment at each site, was randomized. The variance between Resi instruments was small. The measured mean basic density of 50 mm outerwood cores across all plots was 542 kg/m3, while Resi-predicted basic density varied among instruments between 535 and 547 kg/m3. One Resi instrument underpredicted basic density by 9 kg/m3 and another overpredicted by 5 kg/m3. The operator had no effect on the basic density prediction. Resi PD400 or PD500 instruments gave similar basic density predictions.

Modified re-entrant auxetic metamaterials with energy absorption enhancement

The re-entrant auxetic topology was one of the first unit-cells proposed to build cellular auxetic structures. This unit cell (UC) is still widely used in energy-absorbing systems, but there is considerable scope for enhancing its design. This paper describes a series of experimental tests and finite element (FE) models used to evaluate the energy absorption capabilities of novel auxetic structures based on replacing straight struts of the re-entrant unit cell with curved-shaped ones. Three structures have been first designed and manufactured using fused deposition modeling (FDM) 3D printing techniques. The samples have then been subjected to quasi-static compressive testing. The results have been compared with those of a traditional re-entrant structure having similar relative densities and showed that the modified metamaterial topologies demonstrate significantly improved energy absorption and specific energy absorption (SEA) capabilities. In addition, all the proposed new topologies exhibit negative Poisson’s ratio (NPR). After selecting the structure with the highest SEA, a geometrical parametric analysis has been performed to investigate the design space to enhance overall SEA and NPR values. The proposed work provides an overview of the state-of-the-art in re-entrant auxetic structures and introduces a new class of modified re-entrant metamaterials with remarkable energy absorption capability.

Comparative Analysis of Nickel-Phosphine Complexes with Cumulated Double Bond Ligands: Structural Insights and Electronic Interactions via ETS-NOCV and QTAIM Approaches.

This study presents a comprehensive analysis of nickel-phosphine complexes, specifically Ni(PH3)2(OCCH2), Ni(PH3)2(H2CCO), Ni(PH3)2(H2CCCH2), Ni(PH3)2(NNCH2), and Ni(PH3)2(η1-H2CNN). Utilizing ETS-NOCV analysis, we explored orbital energy decomposition and the Hirshfeld charges of the ligands, providing insights into the electronic structures and donor-acceptor interactions within these complexes. The interactions in the ketene and allene complexes exhibit similar deformation densities and NOCV orbital shapes to those calculated for Ni(PH3)2(NNCH2), indicating consistent interaction characteristics across these complexes. The total interaction energy for all η2 complexes is observed to be over 60 kcal/mol, slightly exceeding that of the analogous carbon dioxide complex reported earlier. Furthermore, the study highlights the stronger back-donation as compared to donor interactions across all η2 complexes. This is further corroborated by Hirshfeld analysis, revealing the charge distribution dynamics within the ligand fragments. The research offers new perspectives on the electron distribution and interaction energies in nickel-phosphine complexes, contributing to a deeper understanding of their catalytic and reactive behaviors.

Decision Science-Driven Assessment of Ti Alloys for Aircraft Landing Gear Beams

Titanium alloys, with their low density, exceptional mechanical properties, and outstanding corrosion resistance, play a vital role in various aerospace applications. Our decision science-driven assessment focused on metastable β, near-β, α + β, and near-α Ti alloys for landing gear applications, integrating multiple-attribute decision-making (MADM) methods, principal component analysis (PCA), and hierarchical clustering (HC) is based on current literature. The ranks of the alloys evaluated by diverse MADM methods were consistent. The methodology identifies five top-ranked Ti alloys assists and verifies the guidelines for alloy design. The top-ranked alloy, Ti1300-BM-nano-α (alloy chemistry: Ti-5Al-4V-4Mo-3Zr-4Cr, solution treatment: 800 °C for 1 h followed by air cooling—solution treated below β transus, and aging: 500 °C for 4 h followed by air cooling), stands out with a percentage elongation (%EL) ~3.3 times greater than the benchmark or goal (density, d = ~4.6 g/cm3; yield strength YS = ~1250 MPa; %El = ~5), while maintaining similar density and yield strength. The analyses underline that metastable β Ti alloys comprising globular primary α + trans β matrix coupled with α precipitates in trans β are the base optimal microstructure to fine-tune using thermomechanical processing for aircraft landing gear applications.

Investigating the system flotation kinetics of fine chalcopyrite in a REFLUX™ flotation cell: Part II low-grade ores

The flotation performance of the REFLUX™ Flotation Cell (RFC™) was assessed and quantified through a performance ratio relative to a bench scale mechanical cell. This new work extended the previous study (Parkes et al., 2022) on a model feed to cover two industrial low-grade chalcopyrite feeds, Feed A and Feed B, with Feed B containing a surface-active slime component. The initial phase of the work covered the sensitivity of the performance ratio to the changes in the process conditions in the mechanical cell, notably the gas flux and the feed pulp density. In general, the performance ratio was not very sensitive to the gas flux, mainly due to the need to prevent excessive entrainment which limited the applicable range of gas fluxes. Changes to the feed pulp density had a more significant effect on the performance ratio, hence it is recommended the performance ratio of the two systems be assessed at a similar feed pulp density. For both the low-grade ores, the performance of the RFC™, relative to the mechanical cell, was found to be very high. For Feed A, the performance ratio increased with the particle size, exceeding a value of 5 beyond a particle size of 10 µm. In general, a gas-to-feed flux ratio of 1:1 was found to be optimal. For Feed B, containing a surface-active slime component, the ratio typically exceeded a value of 10 and was less dependent on the particle size, pulp density and feed rate. Overall, the performance ratio increased as the feed pulp density decreased, suggesting a very strong improvement in the flotation kinetics within the RFCTM at lower pulp densities. While the selectivity of hydrophobic to hydrophilic material recovery was very high for Feed A, it was significantly reduced for Feed B, suggesting that the transport of the hydrophilic particles was assisted by the surface-active slime component in the feed.

Human Purkinje cells outperform mouse Purkinje cells in dendritic complexity and computational capacity

Purkinje cells in the cerebellum are among the largest neurons in the brain and have been extensively investigated in rodents. However, their morphological and physiological properties remain poorly understood in humans. In this study, we utilized high-resolution morphological reconstructions and unique electrophysiological recordings of human Purkinje cells ex vivo to generate computational models and estimate computational capacity. An inter-species comparison showed that human Purkinje cell had similar fractal structures but were larger than those of mouse Purkinje cells. Consequently, given a similar spine density (2/μm), human Purkinje cell hosted approximately 7.5 times more dendritic spines than those of mice. Moreover, human Purkinje cells had a higher dendritic complexity than mouse Purkinje cells and usually emitted 2–3 main dendritic trunks instead of one. Intrinsic electro-responsiveness was similar between the two species, but model simulations revealed that the dendrites could process ~6.5 times (n = 51 vs. n = 8) more input patterns in human Purkinje cells than in mouse Purkinje cells. Thus, while human Purkinje cells maintained spike discharge properties similar to those of rodents during evolution, they developed more complex dendrites, enhancing computational capacity.