Inhomogeneous Particle Distribution Research Articles

Magnetic-Nanorod-Mediated Nanowarming with Uniform and Rate-Regulated Heating.

Rewarming cryopreserved samples requires fast heating to avoid devitrification, a challenge previously attempted by magnetic nanoparticle-mediated hyperthermia. Here, we introduce Fe3O4@SiO2 nanorods as the heating elements to manipulate the heating profile to ensure safe rewarming and address the issue of uneven heating due to inhomogeneous particle distribution. The magnetic anisotropy of the nanorods allows their prealignment in the cryoprotective agent (CPA) during cooling and promotes subsequent rapid rewarming in an alternating magnetic field with the same orientation to prevent devitrification. More importantly, applying an orthogonal static magnetic field at a later stage could decelerate heating, effectively mitigating local overheating and reducing CPA toxicity. Furthermore, this orientational configuration offers more substantial heating deceleration in areas of initially higher heating rates, therefore reducing temperature variations across the sample. The efficacy of this method in regulating heating rate and improving rewarming uniformity has been validated using both gel and porcine artery models.

Effects of Sn and Mn additions on microstructural characteristics and tensile properties of Mg-1Gd alloy

Effects of Sn, Mn, and their combined additions on microstructural characteristic and tensile properties of extruded Mg-1Gd (G1) alloy are explored. Compared to the sole Sn or Mn addition, an excellent grain refining is happened with the Sn and Mn combined addition. The average grain size of G1, Mg-1Gd-0.8Sn (GS10), Mg-1Gd-0.7Mn (GM10) and Mg-1Gd-0.8Sn-0.7Mn (GSM100) alloys is ∼21.3, 10.1, ∼12.8 and ∼6.8 μm, respectively. The sole Mn addition enhances the strength and ductility of G1 alloy. The forming the fine α-Mn particles and grain refining are attributed to the improved properties of GM10 alloy. The sole Sn addition increases the yield strength of G1 alloy along extrusion direction (ED), but it decreases along transverse direction (TD), The inhomogeneous distribution of coarse GdMgSn particles and formation of TD-split texture should play an important role. The combined effects of Sn and Mn additions guarantee high strength-ductility synergy of GSM100 alloy. The GSM100 alloy exhibits the ultimate strength, yield strength and ductility of ∼276, ∼158 MPa and 24.7 % along ED, and ∼253, ∼157 MPa and 17.5 % along TD, respectively. The jointly effect of the fine grains, a lot of fine GdMgSn and α-Mn particles, the texture weakening and Sn solute atom contributes to the enhancement of properties of GSM100 alloy.

Visualization of Inhomogeneous Strain and Particle Distribution in a Shape Memory Alloy via Composite Reconstruction of 3DXRD Data

Visualization of Inhomogeneous Strain and Particle Distribution in a Shape Memory Alloy via Composite Reconstruction of 3DXRD Data

Exploring optimal cathode composite design for high-performance all-solid-state batteries

All-solid-state batteries (ASSBs) have attracted considerable attention due to their high stability, offering a safer alternative to currently used batteries. Extensive research has been conducted to improve cathode part performance. However, the conventional hand mixing (HM) process results in inhomogeneous particle distribution, causing poor interparticle contact due to uneven stress distribution, and the solution process causes unwanted solid electrolyte (SE) deterioration when using a polar solvent although it ensures uniform SE distribution. To overcome these limitations, based on the design rule considering SE surface coverage of less than 100 %, we propose a cathode/SE composite, showing decent ionic/electronic conductivities, uniform SE distribution, and intimate interparticle contact, achievable through a mass-producible mechanical mixing (MM) process. Unlike the HM cell, the MM cell forms well-defined ionic percolating pathways and shows excellent structural stability. Consequently, the MM cell exhibits improved capacity retention during 1000 cycles and stable cyclability even under the harsh condition of 7 wt% SE. Finite element analysis theoretically demonstrates that uniform electrode and electrolyte currents are responsible for the improved performances including increased cathode utilization efficiency and reduced overpotentials. This study reveals the importance of composite design and uniform SE distribution in developing high-performance ASSBs at a practical cell level.

Liquid‐Phase Preparation of Low‐Tortuosity Composite Cathode for High Active Material Content All‐Solid‐State Lithium Batteries

AbstractThe all‐solid‐state lithium batteries (ASSLBs) stand as a promising candidate for the next generation of high‐energy‐density batteries with superior safety. Nevertheless, achieving high energy density in ASSLBs necessitates the simultaneous realization of high active material content and loading, posing a significant challenge in ensuring effective Li‐ion conduction within the cathode. Notably, the inhomogeneous distribution of cathode particles causes high porosity and tortuosity within the composite cathodes, thereby adversely impacting the electrochemical performance of the battery. Herein, an in situ liquid‐phase method for the fabrication of LiNi0.8Co0.1Mn0.1O2(NCM811) composite cathode is proposed. This strategy ensures the generation of uniformly distributed and densely packed composite cathode, establishing a well‐networked conduction path that ensures exceptional electronic and ionic conductivity. ASSLBs utilizing LP‐cathode exhibit outstanding electrochemical performance. It delivers a high capacity of 233.3 mAh g−1 at 0.05 C with superior rate capability and remarkable long‐term cycling stability. Moreover, ASSLBs manifest exceptional electrochemical performance, even at a high cathode active material content of 80%. This underscores the efficacy of the liquid‐phase method in constructing low‐tortuosity electrodes and accelerating charge transport kinetics, thereby enhancing the overall performance of ASSLBs. This approach holds promise for addressing the challenges associated with achieving high energy density and facilitating the development of ASSLBs.

Simulation and experimental investigation of material removal profile based on ultrasonic vibration polishing of K9 optical glass

Ultrasonic vibration polishing (UVP) is an important method for the precision processing of optical glass, which is good for improving surface quality and processing efficiency. So far, the material removal mechanism in UVP is not well understood and the various process parameters involved are not considered. To achieve ultra-precision polishing under optical glass, this paper carries out the axial UVP method. The material removal profile (MRP) is critical to affect the surface accuracy. A new MRP is developed for UVP based on the Urick attenuation model and the proposed material removal coefficient distribution function, considering the dynamic pressure changes under ultrasonic vibration, the attenuation effect of the acoustic pressure propagation process and the inhomogeneous distribution of the abrasive particles in the contact area during the ultrasonic electro-spindle rotation. Through a series of polishing experiments and simulations, the results show that the maximum errors of the actual material removal depth (MRD) and the actual material removal rate (MRR) from the model simulation results are 8.54% and 9.92%, respectively. The accuracy of the model is further demonstrated by the Pearson correlation coefficient. When the amplitude of UVP is 9 µm, Sa and Ra are 60 nm and 68 nm, which are reduced by 37.50% and 22.73%, respectively, compared with conventional polishing. This research can contribute to the deterministic processing of UVP, and provide a theoretical basis for the application of optical glass.

Enhancement of energy storage in nanocomposite thin films: Investigating PVDF-ZnO and PVDF-TZO for improved dielectric and ferroelectric characteristics

In contrast to a polymer nanocomposite for high energy density application, a lead-free material such as zinc oxide (ZnO) and a non-toxic polymer matrix such as polyvinylidene fluoride (PVDF) can serve as a potential candidate for use in eco-friendly applications. In the present report, an effort has been made to enhance the dielectric behaviour of the PVDF-based nanocomposites by adding ZnO nanoparticles (NPs) and TiO2-coated ZnO NPs (TZO) as nanofillers. A wet chemical precipitation technique was adopted to synthesize the thin films of PVDF,PVDF-ZnO, and PVDF-TZO nanocomposites. The structural, dielectric, ferroelectric, and energy density studies of PVDF, PVDF-ZnO, and PVDF-TZO nanocomposites thin films were performed for different concentrations (10%, 20%, 30%, and 40%) of nanofillers. Structural characterization carried out using x-ray diffraction studies confirmed the formation of PVDF-ZnO and PVDF-TZO nanocomposite thin films as the diffraction peaks (110) and (200) belonging to β-phase of PVDF, and (100, (002), (101), (110), (103), (200), (112), and (210) peaks were observed for ZnO, and (200), (116), (202) peaks belonging to TiO2 in case of PVDF+ 10% TZO and PVDF+40% TZO thin films. The functional groups belonging to β-phase of PVDF and ZnO were detected using a Fourier transform infrared spectrometer (FTIR). The surface microstructural of pure PVDF thin films showed spherulites and microimages of PVDF+ 10% ZnO and PVDF+ 10% TZO thin films depicted the inhomogeneous distribution of particles in the PVDF matrix. The maximum value of the dielectric constant, the maximum value of energy density, maximum remnant polarization, and the minimum value of dielectric loss for PVDF-TZO. PVDF-TZO thin films show an energy density of 65.3 μJ/cm3 for 40% of the nanofiller (TZO).

SURFACE MODIFICATION OF ALUMINA-SILICA BY ADDITIVE AGENT USING SOL-GEL METHOD AS FILLER DENTAL COMPOSITE

Background: Macro-sized and inhomogeneous distribution of ceramic filer particles make it difficult to obtain smooth surfaces of dental composite after polishing. Objective. This study aims to synthesize alumina silica (Al2O3-SiO2) fillers using sol gel method with the additives agent chitosan 5%, 10% and polyethylene glycol (PEG) 5% to produce micro particle size and evenly distributed particle as filler dental composite. Methods. The type of research is descriptive explorative. The sol-gel process was utilized to synthesize filler particles of Al2O3-SiO2. TEOS was dissolved in ethanol and mixed with acetic acid as catalyts. Al2(NO3)3 was added into the solution and mixed homogenously. Subsequently, the additive agents (Chitosan 5%, chitosan 10% and PEG) were mixed into the mixture for 30 minutes. Drying the samples for 48 hours at 60°C in the oven. The Dynamic light scattering (DLS) SZ-1 was used to evaluate the size, particle distribution and zeta potential. Result. The results showed that the addition of chitosan 10% produced a smaller size of Al2O3-SiO2 compared to other samples. A homogeneous particle distribution is shown in the sample with PEG 5%. Meanwhile, zeta potential values of the filler particles Al2O3-SiO2 with the addition of chitosan 10% shows the biggest value. Conclusion: The additive agent of chitosan 10% can modify the surface of filler Al2O3-SiO2 in order to inhibit particle growth more effectively but better particle distribution is shown in samples with PEG 5% due to the lower viscosity than chitosan thus it is easily homogenized in the solution

Optimizing Plasmonic Microarray Biosensors: Custom Optical System for Enhanced Evaluation and Characterization

This paper presents the design and implementation of a tailored optical system for rapid characterization of transmission-based localized surface plasmon resonance (LSPR) biosensors. The system incorporates a motorized monochromator, offering extreme versatility in experimenting with wavelength resolution and bandwidth of the illumination. This setup streamlines the process of determining optimal chip design parameters such as the density of nanoparticles and the number of detection wavelengths required, as measurements are fully automated and software-driven. Furthermore, the system facilitates straightforward detection of manufacturing errors, including misaligned spots or inhomogeneous particle distribution, enhancing overall efficiency and reliability in biosensor evaluation.

Development of fully equiaxed microstructure in Scalmalloy® through powder bed fusion using a ring-mode laser beam

Powder bed fusion experiments were conducted to investigate the microstructure of Scalmalloy® utilizing standard circular and Adjustable Ring-Mode (ARM) laser beams. The ARM laser beam produced an almost fully equiaxed grain structure, characterized by a significantly thicker Fine Grain (FG) band, compared to the circular laser beam with the same overall volumetric energy density. The discussion explored the mechanisms underlying this remarkable advancement, with a particular focus on the nucleation role of the L12 Al3(ScxZr1-x) phase. Among various theories explaining the inhomogeneous distribution of L12 particles, the findings were found to be more consistent with the primary precipitation at low cooling rates. The research indicates the potential for achieving a fully equiaxed microstructure through heat source modulation without compromising productivity.

Modelling of ductile failure in materials with heterogeneous particle structure using localization analysis

In this study, we evaluate the use of strain localization analysis based on the imperfection band approach to model the effect of heterogeneous particle distribution on the ductile failure of structural metallic materials. To this end, tensile tests are performed on smooth and notched samples made of aluminium alloy AA6110 with an equiaxed grain structure and an inhomogeneous distribution of the constituent particles. The constituent particles are assumed to be the main contributors to the ductile failure of the alloy. By varying the heat treatment of the alloy, three different materials are considered with different strength, work hardening, and ductility, while the grain structure and constituent particle distribution are unaltered. Finite element simulations of the tension tests are conducted using both metal and porous plasticity models and the stress–strain histories of the elements in the minimum section of the specimen are used in strain localization analyses. In these analyses, ductile failure is assumed to occur when the strain rate inside a thin, planar imperfection band becomes infinite. The imperfection band is modelled with porous plasticity, using either a higher initial porosity than in the bulk material or by adding void nucleation. It is found that the ductility of the materials is most accurately captured by modelling the imperfection band by stress-enhanced nucleation.

Simultaneous Improvement in Strength and Ductility of TC4 Matrix Composites Reinforced with Ti1400 Alloy and In Situ-Synthesized TiC

To overcome the tradeoff between strength and ductility of materials and obtain titanium matrix composites with excellent mechanical properties, in this study, the in situ-synthesized TiC particles and Ti-Al-V-Mo-Cr (Ti1400) alloy-reinforced Ti6Al4V (TC4) matrix composites ((Ti1400 + TiC)/TC4) were fabricated by low-energy ball milling and spark plasma sintering. The inhomogeneous distribution of TiC particles and Ti1400 alloy, as well as the compositional and structural transition zone, were characterized. The TiC/TC4 composite displayed a significantly higher yield strength and tensile strength compared to the TC4 alloy. However, the total elongation of the TiC/TC4 composite was only 57% of that in the TC4 alloy. In contrast, the (Ti1400 + TiC)/TC4 composites exhibited noticeably higher total elongation than the TiC/TC4 composite. Furthermore, the tensile strength of the composite increased with the increase in Ti1400 alloy content. The increase in strength can be attributed to solid solution strengthening and fine grain strengthening. The compositional and structural transition zone, formed by element diffusion, provided a better interface combination between the reinforcements and TC4 matrix. In the transition zone and Ti1400 region, a large number of α/β interfaces can effectively alleviate the stress concentration, and the increase in the β phase can bear more plastic deformation, which is conducive to improving the elongation of the composite. As a result, the (Ti1400 + TiC)/TC4 composites exhibited simultaneous improvements in strength and ductility.

Recovery and Characterization of Copper Oxide from Cu-Foil Waste by Combination Method of Acid Leaching and Precipitation

<span lang="EN-US">Lithium ion batteries have been widely applied in portable electronic devices and electric vehicles as high-density energy storage. The significant consumption of lithium ion batteries is outweighed by the threat to the environment of battery waste. Recovery of valuable metals contained in lithium ion batteries, such as Cu foil, is one of the efforts to overcome environmental pollution due to copper metal. The hydrometallurgical method is used in the recovery process, which includes leaching using nitric acid and precipitation using oxalic acid. The material obtained was copper oxide (CuO), which was analyzed using XRD, SEM-EDX, and FTIR to determine the characteristics of the sample. XRD analysis showed that the crystallinity of CuO was in accordance with the database. SEM images confirm the presence of agglomeration and inhomogeneous particle distribution in the samples. FTIR analysis confirmed the formation of the CuO phase, and the EDX results showed the purity of the sample, which consisted of Cu and O elements. Based on the research, CuO was successfully produced from the recovery of Cu Foil waste.</span>

Unified torque scaling in counter-rotating suspension Taylor-Couette flow.

Torque measurements are reported for the Taylor-Couette flow of a neutrally buoyant non-colloidal suspension in the counter-rotation regime up to a particle volume fraction of [Formula: see text]. A unified scaling relation for the dimensionless torque (the pseudo-Nusselt number) of the form [Formula: see text] is shown to hold over a range of Taylor numbers [Formula: see text] that covers primary, secondary and tertiary bifurcating states; here, [Formula: see text] is the reduced Taylor number, [Formula: see text] is the critical Taylor number at primary bifurcation and [Formula: see text] is the relative viscosity of the suspension. Possible effects of flow transitions and inhomogeneous distribution of particles on torque scaling are discussed. This article is part of the theme issue 'Taylor-Couette and related flows on the centennial of Taylor's seminal Philosophical Transactions paper (part 1)'.

Enhanced photocatalytic degradation of 4-nitrophenol using polyacrylamide assisted Ce-doped YMnO3 nanoparticles

This research article mainly reports on the precise structural, optical, and photocatalytic properties of cerium (Ce)-substituted yttrium manganite (YMnO3) nanoparticles synthesized by the polyacrylamide gel method. The characteristics of YMnO3 were investigated by the substitution of Ce into the Y site at various molar percentages. The Raman and X-ray diffraction (XRD) analyses confirmed the pure phase of hexagonal YMnO3, supported by the Rietveld refinement. The microstructural studies indicate inhomogeneous and irregular particle distribution. The X-ray photoelectron spectroscopy (XPS) results show the presence of two ionic states of Mn and Ce along with Y3+ state and oxygen vacancies. Extensive optical exploration using photoluminescence (PL) spectroscopy and UV–Vis–NIR analysis indicates that the intensity of absorption peak increases in the visible region, while the bandgap decreases from 1.42 to 1.30 eV with the Ce ion doping (5 mol%–15 mol%). Photocatalytic properties of the polycrystalline nanoparticles were investigated by degradation of the pollutant 4-nitrophenol. The process of amplified photocatalysis process was elucidated by the lowered bandgap and rate of charge carrier recombination. It can be conjugated from this study that the synthesized nanoparticles may be employed as highly efficient (92.8%) visible light-triggered photocatalysts in a variety of real-world applications.

Thermodynamic-induced geometry of self-gravitating systems

A new approach based on the nonequilibrium statistical operator is presented that makes it possible to take into account the inhomogeneous particle distribution and provides obtaining all thermodynamic relations of self-gravitating systems. The equations corresponding to the extremum of the partition function completely reproduce the well-known equations of the general theory of relativity. Guided by the principle of Mach's "economing of thinking" quantitatively and qualitatively, is shown that the classical statistical description and the associated thermodynamic relations reproduce Einstein's gravitational equation. The article answers the question of how is it possible to substantiate the general relativistic equations in terms of the statistical methods for the description of the behavior of the system in the classical case.

Dispersion medium crystallization effect on the magnetic susceptibility of ferrofluids

Ferrofluids (magnetic colloids) with a dispersion medium crystallizing with a decrease in temperature are investigated. Temperature dependences of the dynamic magnetic susceptibility of such ferrofluids were measured. For comparison, similar susceptibility dependences of ferrofluids with a dispersion medium that does not form a crystalline structure when solidified by cooling are also presented. It is demonstrated that crystallization of the dispersion medium leads to an inhomogeneous spatial distribution of dispersed phase particles and the formation of regions of high particle concentration. This does not happen in the case of colloids with a dispersion medium that does not form a crystalline structure. It is concluded that the formation of regions of high concentrations of dispersed phase particles during crystallization is the cause for a jump in colloid magnetic susceptibility. This conclusion refutes the previously existing opinion that the reason for the jump in the susceptibility of a ferrofluid at the temperature of transition to a solid state is the blocking of Brownian degrees of freedom of particles.

Interaction between η-Ni3Ti and reversed austenite within Custom 465 stainless steel: experimental evidence and related patents investigation

After various aging treatment conditions, precipitated nano-sized intermetallic compound particles, i.e., η-Ni3Ti, with a rod-like shape and reversed austenite with various shapes, i.e. lath, blocky, and granular morphologies, were distributed within martensite laths of Custom 465 stainless steel in the present study. Identified via STEM mapping and corresponding diffraction patterns, the precipitates of η-Ni3Ti had a hexagonal closed-packed (HCP) crystal structure and adopted a Burgers orientation relationship, i.e., {011}α′ // {0001}η ; <111‾>α′ // <112‾0>η, with the martensite matrix. Furthermore, the size of the tiny η-Ni3Ti particles increased with the isothermal aging temperature and time, indicating that the precipitation behavior obeyed the thermal activation mechanism. Despite forming simultaneously upon aging treatment, the formations of reversed austenite and η-Ni3Ti particles were mutually independent due to the excess content of Ni in the precipitation hardened (PH) stainless steel. In addition, the existence of such reversed austenite also led to the inhomogeneous distribution of dislocations due to the discrepancy in the thermal expansion coefficients of reversed austenite and martensite, which further resulted in the inhomogeneous distribution of η-Ni3Ti particles and a wider Vickers hardness distribution, especially after aging at low temperature.

Experimental investigation of preferential concentration in zooplankton swimming in turbulence.

Turbulence can cause particles to accumulate within specific regions of the flow. One mechanism responsible for this phenomenon, called preferential concentration, consists in particle-fluid interactions yielding inhomogeneous spatial distribution of particles into clusters or depleted regions due to density difference or finite-size effects. In the case of living particles such as plankton, clustering may also originate from their motility or from their behavioral response to turbulent forcing. Preferential concentration of plankton has attracted much attention, because it is a key determinant of encounter rates and therefore relevant for a wide range of ecological processes. However, most studies have focused on microscopic cells, and consequently the case of larger organisms remains poorly studied. Here, we use high-performance particle tracking and three-dimensional Voronoï analysis to test for the emergence of clustering in the spatial distribution of calanoid copepods, the most important metazoans in the oceans in terms of biomass. We found that neither inertia nor motility resulted in significant departure from a random Poisson process over a range of turbulence intensity from very strong to moderate. However, we observed weak clustering in calm water, which may originate from hydrodynamic and olfactory interactions between organisms. Our results improve our understanding of fluid-particle interactions in the zooplankton and have important implications for the modeling of their encounter rates in turbulence.

Radiation and Polarization Signatures from Magnetic Reconnection in Relativistic Jets. II. Connection with γ-Rays

Abstract It is commonly believed that blazar jets are relativistic magnetized plasma outflows from supermassive black holes. One key question is how the jets dissipate magnetic energy to accelerate particles and drive powerful multiwavelength flares. Relativistic magnetic reconnection has been proposed as the primary plasma physical process in the blazar emission region. Recent numerical simulations have shown strong acceleration of nonthermal particles that may lead to multiwavelength flares. Nevertheless, previous works have not directly evaluated γ-ray signatures from first-principles simulations. In this paper, we employ combined particle-in-cell and polarized radiation transfer simulations to study multiwavelength radiation and optical polarization signatures under the leptonic scenario from relativistic magnetic reconnection. We find harder-when-brighter trends in optical and Fermi-LAT γ-ray bands as well as closely correlated optical and γ-ray flares. The swings in optical polarization angle are also accompanied by γ-ray flares with trivial time delays. Intriguingly, we find highly variable synchrotron self-Compton signatures due to inhomogeneous particle distributions during plasmoid mergers. This feature may result in fast γ-ray flares or orphan γ-ray flares under the leptonic scenario, complementary to the frequently considered minijet scenario. It may also imply neutrino emission with low secondary synchrotron flux under the hadronic scenario, if plasmoid mergers can accelerate protons to very high energy.