Packing Density Research Articles

Anomalous flocking in nonpolar granular Brownian vibrators

Using Brownian vibrators, we investigated the structures and dynamics of quasi-2d granular materials, with packing fractions (ϕ) ranging from 0.111 to 0.832. Our observations revealed a remarkable large-scale flocking behavior in hard granular disk systems, encompassing four distinct phases: granular fluid, flocking fluid, poly-crystal, and crystal. Anomalous flocking emerges at ϕ = 0.317, coinciding with a peak in local density fluctuations, and ceased at ϕ = 0.713 as the system transitioned into a poly-crystal state. The poly-crystal and crystal phases resembled equilibrium hard disks, while the granular and flocking fluids differed significantly from equilibrium systems and previous experiments involving uniformly driven spheres. This disparity suggests that collective motion arises from a competition controlled by volume fraction, involving an active force and an effective attractive interaction resulting from inelastic particle collisions. Remarkably, these findings align with recent theoretical research on the flocking motion of spherical active particles without alignment mechanisms.

Achieving Record C2H2 Packing Density for Highly Efficient C2H2/C2H4 Separation with a Metal‐Organic Framework Prepared by a Scalable Synthesis in Water

Adsorptive C2H2/C2H4 separation using metal‐organic frameworks (MOFs) has emerged as a promising technology for the removal of C2H2 (acetylene) impurity (1%) from C2H4 (ethylene). The practical application of these materials involves the optimization of separation performance as well as development of scalable and green production protocols.Herein, we report the efficient C2H2/C2H4 separation in a MOF, Cu(OH)INA (INA: isonicotinate) which achieves a record C2H2 packing density of 351 mg cm‐3 at 0.01 bar through high affinity towards C2H2. DFT (density functional theory) calculations reveal the synergistic binding mechanism through pore confinement and the oxygen sites in pore wall.The weakly basic nature of binding sites leads to a relatively low heat of adsorption (Qst) of approximately 36 kJ/mol, which is beneficial for material regeneration and thermal management. Furthermore, a scalable and environmentally friendly synthesis protocol with a high space‐time yield of 544 kg m‐3 day‐1 has been developed without using any modulating agents. This material also demonstrates enduring separation performance for multiple cycles, maintaining its efficacy after exposure to water or air for three months.

Achieving Record C2H2 Packing Density for Highly Efficient C2H2/C2H4 Separation with a Metal-Organic Framework Prepared by a Scalable Synthesis in Water.

Adsorptive C2H2/C2H4 separation using metal-organic frameworks (MOFs) has emerged as a promising technology for the removal of C2H2 (acetylene) impurity (1%) from C2H4 (ethylene). The practical application of these materials involves the optimization of separation performance as well as development of scalable and green production protocols.Herein, we report the efficient C2H2/C2H4 separation in a MOF, Cu(OH)INA (INA: isonicotinate) which achieves a record C2H2 packing density of 351 mg cm-3 at 0.01 bar through high affinity towards C2H2. DFT (density functional theory) calculations reveal the synergistic binding mechanism through pore confinement and the oxygen sites in pore wall.The weakly basic nature of binding sites leads to a relatively low heat of adsorption (Qst) of approximately 36 kJ/mol, which is beneficial for material regeneration and thermal management. Furthermore, a scalable and environmentally friendly synthesis protocol with a high space-time yield of 544 kg m-3 day-1 has been developed without using any modulating agents. This material also demonstrates enduring separation performance for multiple cycles, maintaining its efficacy after exposure to water or air for three months.

Collective dynamics and pair-distribution function of active Brownian ellipsoids in two spatial dimensions

While the collective dynamics of spherical active Brownian particles is relatively well understood by now, the much more complex dynamics of nonspherical active particles still raises interesting open questions. Previous work has shown that the dynamics of rod-like or ellipsoidal active particles can differ significantly from that of spherical ones. Here, we obtain the full state diagram of active Brownian ellipsoids in two spatial dimensions without hydrodynamic interactions depending on the Péclet number and packing density via computer simulations. The system is found to exhibit a rich state behavior that includes cluster formation, local polar order, polar flocks, and disordered states. Moreover, we obtain numerical results and an analytical representation for the pair-distribution function of active ellipsoids. This function provides useful quantitative insights into the collective behavior of active particles with lower symmetry and has potential applications in the development of predictive theoretical models.

Influence of Cathode Calendering Density on the Cycling Stability of Li-Ion Batteries Using NMC811 Single or Poly Crystalline Particles

Abstract Calendering of battery electrodes is a commonly used manufacturing process that enhances electrode packing density and therefore improves the volumetric energy density. While calendering is standard industrial practice, it is known to crack cathode particles, thereby increasing the electrode surface area. The latter is particularly problematic for new Ni-rich layered transition metal oxide cathodes, such as NMC811, which are known to have substantial surface-driven degradation processes. To establish appropriate calendering practices for these new cathode materials, we conducted a comparative analysis of uncalendered electrodes with electrodes that have a 35% porosity and 25% for single crystal and polycrystalline NMC811. PC cathodes show clear signs of cracking and decrease in rate capability when calendered to 25% porosity, whereas SC cathodes, achieve better cycling stability and no penalty in rate performance at these high packing densities. These findings suggest that SC cathodes should be calendered more densely, we provide a comprehensive overview of both electrochemical and material characterisation methods that corroborate why PC and SC electrodes show such different degradation behaviour. Overall, this work is important because it shows how new single-crystal cathode materials can offer additional advantages in terms of rate performance and cycling stability by calendaring them more densely

Stress correlations in near-crystalline packings

We derive exact results for stress correlations in near-crystalline systems in two and three dimensions. We study energy minimized configurations of particles interacting through Harmonic as well as Lennard-Jones potentials, for varying degrees of microscopic disorder and quenched forces on grains. Our findings demonstrate that the macroscopic elastic properties of such near-crystalline packings remain unchanged within a certain disorder threshold, yet they can be influenced by various factors, including packing density, pressure, and the strength of inter-particle interactions. We show that the stress correlations in such systems display anisotropic behavior at large lengthscales and are significantly influenced by the pre-stress of the system. The anisotropic nature of these correlations remains unaffected as we increase the strength of the disorder. Additionally, we derive the large lengthscale behavior for the change in the local stress components that shows a 1/r^d1/rd radial decay for the case of particle size disorder and a 1/r^{d-1}1/rd−1 behavior for quenched forces introduced into a crystalline network. Finally, we verify our theoretical results numerically using energy-minimised static particle configurations.

An extensive analysis of SOL properties in high-δ plasmas in ASDEX Upgrade

A set of dedicated H-mode discharges with constant heating power combining Neutral Beam Injection and Electron Cyclotron Resonance Heating have been executed at the ASDEX Upgrade tokamak using a high triangularity magnetic geometry in order to investigate the impact of filamentary transport to divertor and non-divertor components. The evolution of upstream scrape-off layer (SOL) profiles have been correlated with dedicated separatrix quantities, mostly with the turbulence control parameter αt (Eich and Manz 2021 Nucl. Fusion 61 086016) describing the turbulence level at the separatrix. With increasing αt , a broadening of the upstream density profiles in the near-SOL together with the formation of a density shoulder in the far-SOL have been observed. This phenomenon is associated with an enhanced filamentary transport dominating the radial turbulent transport in the far-SOL and confirmed by means of the cooling water calorimetry on non-divertor components. The probe measurements conducted with the ball-pen probe-head mounted on the midplane manipulator and a retarding-field analyzer close to the limiter surface indicate that the key mechanism increasing the radial filamentary transport to the first wall is an increase of the particle flux Γr,fil , caused primarily by the packing fraction fPF,fil and the filament density ne,fil . At the same time, the electron temperature Te and ion temperature Ti measured close to the limiter surface show only small variations above αt > 0.5. Both the filamentary heat flux and the gross erosion derived from the first wall probe measurements reach a magnitude that should be considered in the design of future fusion reactors.

Crystal Structure, Infrared Reflection Spectrum, and Improved Microwave Dielectric Characteristics of Ba4Sm28/3Ti18O54 Ceramics via One-Step Reaction Sintering

High-k Ba4Sm28/3Ti18O54 ceramics with improved microwave dielectric characteristics were successfully fabricated using the one-step reaction sintering (RS) route. The sintering characteristics, microstructure, crystal structure, infrared reflection spectrum, and microwave dielectric characteristics of Ba4Sm28/3Ti18O54 ceramics prepared by the RS route were systematically investigated. Samples prepared by the RS route exhibited single-phase orthorhombic tungsten–bronze structure and dense microstructure at optimum sintering temperature. Compared with the conventional solid-state (CS) process, the Ba4Sm28/3Ti18O54 ceramics fabricated by the RS route presented a smaller temperature coefficient (TCF), a higher quality factor (Q × f), and a higher permittivity (εr). The improved microwave dielectric characteristics were highly dependent on the theoretical permittivity, atomic packing fraction, suppression of Ti3+, and Ti-site bond valence. Excellent combined microwave dielectric characteristics (TCF = −7.9 ppm/°C, Q × f = 9519 GHz, εr = 80.26) were achieved for Ba4Sm28/3Ti18O54 ceramics prepared by RS route sintered at 1400 °C, suggesting the RS route was a straightforward, economical and effective route to prepare high-performance Ba4Sm28/3Ti18O54 ceramics with promising application potential.

Reversible Adsorption of Ammonia in the Crystalline Solid of a CO2H-Functionalized Cyclic Oligophenylene.

Ammonia (NH3) is a viable candidate for the storage and distribution of hydrogen (H2) due to its exceptional volumetric and gravimetric hydrogen energy density. Therefore, it is desirable to develop NH3 storage materials that exhibit robust stability across numerous adsorption-desorption cycles. While porous materials with polymeric frameworks are often used for NH3 capture, achieving reversible NH3 uptake remains a formidable challenge, primarily due to the high reactivity of NH3. Here, we advocate the use of CO2H-functionalized cyclic oligophenylene 1a with high chemical stability as a novel single-molecule-based adsorbent for NH3. Simple reprecipitation of 1a selectively yielded microporous crystalline solid 1a (N). Crystalline 1a (N) adsorbs up to 8.27 mmol/g of NH3 at 100 kPa and 293 K. Adsorbed NH3 in the pore of 1a (N) has a packing density of 0.533 g/cm3 at 293 K, which is close to the density of liquid NH3 (0.681 g/cm3 at 240 K). Crystalline 1a (N) also exhibits reversible NH3 adsorption over at least nine cycles, sustaining its storage capacity (1st cycle: 8.27 mmol/g; 9th cycle: 8.25 mmol/g at 100 kPa and 293 K) and crystallinity. During each desorption cycle, NH3 was removed from 1a (N) under reduced pressure (∼65 Pa), leaving <3% of the total uptake, and 1a (N) was fully purged under dynamic vacuum conditions (∼5 × 10-4 Pa at 293 K for 1 h) before the subsequent adsorption cycles. Thus, microporous crystalline 1a (N) can reliably adsorb and desorb NH3 repeatedly, which avoids the need for heat-based activation between cycles.

Conversion of preferred crystalline orientation by annealing and its impacts on the structural, electronic, and optical properties of pulsed laser-deposited CdO thin films

The impact of annealing on the preferred crystalline orientation as well as the structural, electronic, and optical properties of pulsed laser-deposited 150 ± 3 nm thick cadmium oxide (CdO) films was studied. X-ray diffraction analysis revealed that the annealed CdO films have smaller crystallite sizes, as their molecules at the grain boundaries possessed enough kinetic energy to rearrange their preferred crystalline orientation between (111) and (200). The atomic force microscopy and field emission scanning electron microscopy analyses revealed an enhancement in the active surface area with optimized grain boundaries by annealing which facilitates gas adsorption/desorption. DC electrical conductivity depends on the annealing process and reveals two different conduction mechanisms. The direct optical energy gap was decreased from 3.41 eV to 2.76 eV by annealing at 473 K which is greater than the theoretical value, i.e. 2.2 eV, for bulk CdO. The findings agree with the Burstein-Moss effect as a result of the increased carrier concentration following the generation of numerous oxygen vacancy sites and Cd interstitials. However, mutual charge carrier-impurity interaction and charge carrier Columb interaction contributed to narrowing the band gap by increasing the annealing temperature. The enhanced values of Urbach energy, optical packing density, dispersion parameters, optical conductivity, dissipation factor, oscillator strength, and lattice dielectric constant supported the effectiveness of the annealing process on tailoring optoelectronic responses in the infrared region for the CdO thin films for use in optoelectronic devices. Moreover, the calculated linear optical susceptibility, and nonlinear constants (i.e. third-order optical susceptibility and nonlinear refractive index) were the highest for CdO films annealed at 473 K. The improved value of the figure of merit, solar material protection factor, and solar skin protection factor for the CdO films, annealed at 473 K supports its use in several photovoltaic applications, including solar cells.

The particle sizes of milled wheat fractions affect the in vitro starch digestibility and quality parameters of wire-cut cookies made thereof.

Slow digestion of starch is linked to various health benefits. The impact of wheat particle size on in vitro starch digestibility and quality of wire-cut cookies was here evaluated by including four soft wheat fractions [i.e. flour (average diameter, 83 μm), fine farina (643 μm), coarse farina (999 μm) and bran (1036 μm)] in the recipe. The susceptibility of starch in these fractions to in vitro digestion decreased with increasing particle size, resulting in a 76% lower digestion rate for coarse farina than for flour as found with the single first-order kinetic model. Starch was protected from hydrolysis likely due to delayed diffusion of pancreatic α-amylase through the intact farina cell walls. When 20-65% starch in flour for the control cookie recipe was substituted with the same percentages in fine and coarse farina, the starch digestion rate decreased when substitution levels increased. A 62% lower digestion rate was found at 65% substitution with coarse farina. Cell wall intactness was largely preserved in the cookies and most of the starch appeared as ungelatinised granules. Further, the cookie spread ratio during baking was 48% and 33% higher and the cookies were 63% and 57% less hard than control cookies when made with 65% fine farina and 65% coarse farina, respectively. The relatively low specific surface area of large wheat particles resulted in low water absorption and less dense packing. In conclusion, encapsulation of starch by intact cell walls in coarse wheat fractions makes them promising ingredients when developing starchy food products for controlled energy release.

Supercrystal Engineering of Nanoarrows Enabled by Tailored Concavity.

Self-assembly of nanoparticles into supercrystals represents a powerful approach to create unique and complex superstructures with fascinating properties and novel functions, but the complexity in spatial configuration, and the tunability in lattice structure are still quite limited compared to the crystals formed by atoms and molecules. Herein, shallowly concave gold nanoarrows with a unique concave-convex geometry are synthesized and employed as novel building blocks for shape-directed self-assembly of a wealth of complex 3D supercrystals with unprecedented configurations. The obtained diverse superstructures including six Interlocking-type supercrystals and three Packing-type supercrystals exhibit four types of Bravais lattices (i.e., tP, oI, tI, and oF) and six types of crystallographic space groups (i.e., Pmmm, I222, Pnnm, Ibam, I4/mmm, and Fmmm), which have not been documented in the mesoscale self-assembled systems. It has been revealed that the relative yield of different supercrystal structures is mainly determined by the packing density and deformability of the supercrystals, which are closely related to the tailored concavity of the nanoparticles and is affected by the particle concentration, thus allowing for programmable self-assembly into specific supercrystals through particle shape modulation. The concavity-enabled supercrystal engineering may open a new avenue toward unconventional nanoparticle superstructures with expanded complexity, tunability, and functionality.

Synergistic effects of Gd2O3 and SiO2 in enhancing the acoustic, mechanical, and shielding qualities of borate glasses

This study comprehensively analyzes the gamma radiation shielding, mechanical, and acoustic properties of novel glass composites formulated from B2O3, SiO2, and Gd2O3. Utilizing the MCNPX simulation code and Phy-X: PSD software, key parameters such as Linear Attenuation Coefficient, Half Value Layer (HVL), Mean Free Path (MFP), and Effective Atomic Number (Zeff) were meticulously evaluated for three distinct glass compositions, denoted as GL-1, GL-2, and GL-3. The investigation revealed that incorporating Gd2O3 and SiO2 notably enhances the radiation shielding efficiency of these glasses, which is evident from the decreasing trends in HVL and MFP values across the series. Employing the Makishima and Mackenzie (MM) model, this study further delved into the mechanical and acoustic characteristics of the glass samples. An increase in Gd2O3 and SiO2 content, substituting B2O3, was observed to augment the bond dissociation energy and adjust the packing density, consequently improving the elastic moduli. These mechanical enhancements were quantified through measurements of Young's modulus, bulk modulus, shear modulus, and longitudinal modulus. Acoustic properties were also calculated, including Longitudinal and Transverse velocities, mean velocity, and acoustic impedance. These parameters demonstrated a consistent improvement correlating with the increasing rigidity and mechanical strength of the glass samples, particularly for the GL-3 composition. The study concludes that the GL-3 glass sample exhibits superior performance regarding gamma photon attenuation, mechanical robustness, and acoustic properties. This underscores its potential as an effective material for radiation shielding in various industrial applications, benefiting from its enhanced mechanical and acoustic features.

A Simulation Study on Sieving as a Powder Deposition Method in Powder Bed Fusion Processes

Powder deposition of even and homogeneous layers is a major aspect of every powder bed fusion process. Powder sieving is commonly performed to powder batches outside of the PBF machine, prior to the part manufacturing stage. In this work, sieving is examined as a method of powder deposition rather than a method to solely filter out agglomerates and oversized particles. Initially, a DEM powder model that has been validated experimentally is implemented, and the sieving process is modelled. The sieving process is optimized in order to maximize mass flow, duration of its linear stage and total mass sieved during linearity. For this, a Taguchi design of experiments with subsequent analysis of variance is deployed, proving that the larger the initial powder loaded in the sieve, the larger the sieve stimulation necessary, both in terms of oscillating frequency and amplitude. The sieve’s aperture shape is also evaluated, proving that the more sides the canonical polygon has, the less the mass flow per aperture for the same maximum passing particle size. Then, the quality of the layer produced via controlled sieving is examined via certain layer quality criteria, such as the surface roughness, layer thickness deviation, surface coverage ratio and packing density. The findings prove that controlled sieving can outperform powder deposition via a non-vibrated doctor blade recoater, both in terms of layer surface quality and duration of layer deposition, as proven by surface skewness and kurtosis evaluation.

Strain-dependent work function of metal surfaces: Insights from first-principles investigation

Establishing a fundamental understanding of the relationship between electronic work function (WF) and applied strain is crucial for the development flexible electrodes of and enhancement of metal corrosion resistance. The underlying mechanisms of this relationship have remained unknown, largely due to inconsistencies from previous studies caused by different strain states and the complex impact of anisotropic surface effects. In this study, we employ first-principles methods to investigate the work functions of strained metal surfaces. Our research findings suggest that lateral strain states significantly affect the WF, while strain perpendicular to the surface has minimal influence. Through subjecting the metal surface to linear elastic deformation, we establish a canonical relationship between the work function and strain. Further comparison of work functions under biaxial strain indicates that surfaces with high atom packing density exhibit greater susceptibility to strain. The mechanism behind the strain-dependent WF is attributed to the interplay of bulk electronic structure and surface dipole effects, which. These effects are influenced by volume changes and the redistributedion of charge density. To this end, we propose an effective strain-induced approach for engineering the WF of metal electrode is proposeds, with potential applications in other various materials.

Ionic strength effect on the structure and dynamics of colloidal dispersions with weak attractive interactions

We present a macro- and microrheological study of the effect of ionic strength on the phase behavior, structure and flow properties of colloidal dispersions stabilized by short-range repulsive interactions inferred via co-polymerization of weak acid groups. We investigated the impact of ionic strength, by varying the concentration of natrium chloride (NaCl), on dispersions with only repulsive interactions, but also when additional attractive depletion forces are present due to added non-absorbent polymer, namely polyethyleneoxide (PEO). For dispersions with only repulsive electrosteric interactions, at low particle volume fractions (ϕ < 0.4), increasing ionic strength hardly affects the relative viscosity whereas at higher particle volume fractions, a decrease in viscosity is observed due to a reduced range of electrosteric repulsion between particles, corresponding to a reduction of the effective particle volume fraction ϕeff. For dispersions including attractive interactions, at volume fractions ϕ = 0.45 below the hard sphere freezing point (ϕc=0.5), independently of the ionic strength, the bulk viscosity increases monotonically with increasing PEO concentration due to the transition from a fluid to a fluid/crystalline and finally to a gel state. However, the increase in ionic strength shifts the concentrations of both phase transitions to lower polymer concentrations, indicating that in presence of salt a weaker attraction is required to induce these transitions. At ϕ=0.52, just above ϕc, for dispersions without added salt, broadening of the fluid-crystalline coexistence regime, due to added PEO, results in a viscosity minimum corresponding to different size and packing density of the crystalline regions as observed earlier in Weis et al. [1]. When salt is added, the initial state for dispersions without PEO is a fluid state due to the reduction of ϕeff and the addition of a small amount of PEO leads to an increase in bulk viscosity due to the formation of large crystals for dispersions containing 10 mM NaCl and a network of small, dense crystals of size ≈10 µm when 100 mM NaCl is added. At ϕ=0.54, a result similar to ϕ=0.52 is obtained for dispersions without added salt, whereas in presence of salt, we find that the fluid/crystalline coexistence regime narrows down as the range of electrosteric repulsion decreases and the addition of PEO results in gel formation and gels become more uniform with increasing attraction strength. These investigations demonstrate how superimposed short range electrosteric repulsion and weak depletion attraction affect microstructure and flow behavior of colloidal dispersions.

Atomic and electronic structures of Ni64Zr36 metallic glass under high pressure

Abstract Amorphous metallic alloys, also known as metallic glasses (MGs), are materials with unique physical properties resulting from their disordered yet densely packed atomic structure. The packing density of MGs can be further enhanced by external pressure, forcing the decrease of interatomic distances and modifying both the atomic and electronic structure of an alloy. This work reports on classical molecular dynamics (MD) and density functional theory (DFT) studies of Ni64Zr36 MG in a hydrostatic pressure range of 0-120 GPa. The MD simulations revealed that compression leads to enhanced short-range ordering by increasing the contribution of efficiently packed icosahedral-like clusters. According to the DFT calculations, for pressure above 50 GPa, Zr atoms show a significant change in electronic configuration, with a dominant charge transfer from their s and p to d-states and charge redistribution between Ni and Zr atoms. This variation is correlated with the appearance of pairs with significantly shortened interatomic distances, as detected by the MD. We conclude that the enhanced icosahedral ordering in Ni64Zr36 MG is induced not only by the pressure-driven densification of an alloy but also by a variation of its electronic structure.

Microgels with controlled network topologies by photocrosslinking-assisted continuous precipitation polymerization

In this study, we present a new synthesis methodology based on photo-crosslinking-assisted continuous precipitation polymerization which allows controlling the distribution of crosslinks in microgels In our approach we substituted conventional crosslinking agent by a comonomer carrying photo-crosslinkable 4-oxocyclopent-2-en-1-yl group. Microgel size, morphology, distribution of crosslinks and packing density of the polymer chains are studied as a function of retention time (Rt) in the flow reactor. Dynamic and static light scattering (DLS and SLS) as well as small angle X-ray scattering (SAXS) proved an excellent level of control over the distribution of crosslinks in microgels during the polymerization process. These results were confirmed by atomic force microscopy (AFM), indicating a difference in microgel stiffness and arrangement of the polymer network as resulting from increased Rt.

P-380 Improvement of follicle growth and health during dynamic culture of bovine ovarian cortical tissue (BOCT) is associated to a higher remodeling of the extracellular matrix

Abstract Study question Is improvement of follicle growth and health during dynamic culture in Perifusion Bioreactor (PB) associated to a healthier condition and remodeling of extracellular matrix? Summary answer The dynamic culture in PB allows the extracellular matrix (ECM) network rearrangement improving follicle growth and viability compared to static culture What is known already Over the past two decades, in vitro folliculogenesis has achieved moderate success in large mammals, emerging as a distinctive and reliable method for obtaining secondary follicles. Recently, although dynamic culture in bioreactors has been demonstrated to enhance follicle progression, quality, and viability compared to static culture, less emphasis has been devoted to ECM remodeling. Ovarian tissue ECM plays a crucial role in cell–cell, and cell-ECM interactions involved in follicle activation and growth. The comprehension of ECM function deepens our understanding of follicular development and holds significant promise for future reproductive technologies Study design, size, duration Bovine ovaries (age 8-24 months) were collected at slaughterhouse. BOCT strips (1x1x0.5mm) from the same ovary were cultured in groups of 10 for 14 days in PB (dynamic culture) and conventional dishes (CD, static culture). At the end of culture, collagen thickness and packing density was assessed through PicroSirius red (PSR) staining, follicle stages and quality through histology, and follicle viability through live-dead far-red and propidium iodide labeling under confocal microscopy Participants/materials, setting, methods Neosynthesis and remodeling of collagen fibers was analyzed on PSR-stained samples under polarized light measuring the color of each pixel. A color threshold was set to isolate the four colors seen in PSR-stained samples under polarized light: green, thin fibers (neosynthesized); yellow, mid-sized fibers (low assembly); orange, mid-sized fibers (medium assembly); red, mature thick fibers (high assembly). The color threshold was set as follows: red 2–9, yellow 39-51, orange 10–38, green 52–128 Main results and the role of chance In fresh tissue, analysis of PSR-stained samples showed the following values: Red 1.35; Orange 4.93; Yellow 0.18; Green 0.15. At Day 14, compared to the static culture, culture in PB, exhibits a significantly higher production of green (PB 0.22 vs CD 0.02 P &amp;lt; 0.01) and yellow (PB 0.56 vs CD 0.26 P &amp;lt; 0.05) fibers indicating an improved neosynthesis and remodeling of collagen and ECM health condition. Such higher ECM remodeling after dynamic culture is associated to a significantly higher percentage of secondary follicles (PB 15.4– CD 4.1%, P &amp;lt; 0.01 ), superior follicle quality (grade I/II, PB 70,5 - CD 28.4%, P &amp;lt; 0.01) and viability (PB 70 – CD 41.1%, P &amp;lt; 0.01). PSR analysis suggests that the continuous nutrients and oxygen supply, catabolites removal, and biomechanical stimulation during dynamic PB culture, stimulates the deposition of newly synthesized collagen which in turn, promotes follicle growth Limitations, reasons for caution Although the bovine is a suitable reproductive model for human, such findings should be replicated on human ovarian tissue Wider implications of the findings The aim of ovarian tissue culture is to promote the growth of healthy secondary follicles that can be isolated for further culture to generate MII oocytes. The present findings suggest that adoption of dynamic ovarian tissue culture could enhance the outcome of folliculogenesis in vitro Trial registration number not applicable

Research on the preparation of eco-economical ultra-high performance concrete utilizing graphite tailings resources

Ultra-High Performance Concrete (UHPC) employs river sand as its primary aggregate due to the absence of coarse aggregates, resulting in high production costs and significant ecological impacts, limiting its broader application. To mitigate these challenges, this research investigates the substitution of river sand with industrial waste graphite tailings (GT) in UHPC production. Experimental evaluations assessed changes in wet packing density, workability, mechanical properties, resistance to chloride ion penetration, and heavy metal leaching at various graphite tailings replacement rates (0 %, 25 %, 50 %, 75 %, and 100 %). The microstructural properties of UHPC were analyzed using techniques such as X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analysis (TGA), Mercury Intrusion Porosimetry (MIP), and Scanning Electron Microscopy (SEM). Results indicate that increasing the replacement rate of graphite tailings leads to a gradual decrease in UHPC workability. At a 50 % replacement rate, graphite tailings enhance the wet packing density, contributing to a 7.33 % increase in the 28-day compressive strength. Additionally, graphite tailings can decrease the carbon emissions associated with unit compressive strength by up to 6.96 % and reduce production costs by 20 %. The inclusion of graphite tailings also improves the resistance of UHPC to chloride ion penetration and reduces the leaching of heavy metal ions from the tailings. Microstructural analyses indicate that graphite tailings promote hydration reactions in UHPC without altering the types of hydration products. Additionally, these tailings improve the pore structure of the composite. This study investigates the feasibility of using graphite tailings as a substitute for river sand in the production of UHPC, providing foundational insights for subsequent studies focused on optimizing eco-friendly UHPC formulations that incorporate graphite tailings.