Intrinsic Properties Of Particles Research Articles

Respiratory particles: from analytical estimates to disease transmission

Respiratory particles containing infectious pathogens are responsible for a large number of diseases. To define health politics and save lives, it is important to study their transmission mechanisms, namely the path of particles once expelled. This path depends on several driving factors as intrinsic properties of particles, environmental aspects and morphology of the scenario. Following physical arguments and taking into account the results of experimental works, we consider a mathematical drift model for the mixture composed by two phases: air and particles. The relative motion between the two phases is described by a kinematic constitutive relation. We prove the stability of the model for fixed times and establish an a priori estimate for the total number of infectious particles. The upper bound of this estimate exhibits sound physical dependencies on the driving factors, in agreement with the experimental literature and mounting epidemiological evidences. Namely, we establish that the amount of particles expelled and their emission rate can explain why some people are superspreaders. Several numerical simulations illustrate the theoretical results.

How to Consider the Interfacial Phenomenon in All‐Solid‐State Batteries? – Quantitative Analysis using µ‐Cavity Electrode

AbstractUnderstanding the intrinsic properties of cathode active particles is required to understand how they depend on the charge transfer resistance at solid–liquid or solid‐solid interfaces. Depth‐of‐discharge (DOD)‐dependent charge transport occurs when lithium ions move from the bulk electrolyte to the cathode active particles. However, composite electrodes consist of unevenly distributed active material, conductive additives, and polymeric binder, which complicates the electron/ion conduction path; hence, estimating the DOD‐dependent charge transfer resistance is difficult. However, micro‐sized spherical cathode active particles can be arranged into a cylindrical cavity trap on a microelectrode to evaluate the interfacial behavior of LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode active particles in liquid and solid electrolyte systems. The electrochemical parameters calculated from the resultant Tafel plot can encourage meaningful discussions and demonstrate the reliability of the measurement technique.

Micromechanical mapping of polycrystalline cubic boron nitride composites by means of high-speed nanoindentation: Assessment of microstructural assemblage effects

Polycrystalline cubic boron nitrides (PcBNs) are composites widely used as cutting tool materials due to their exceptional high hardness and wear resistance. Investigation of their micromechanical properties is key for optimizing PcBN’s performance through microstructural design. Within this context, high-speed nanoindentation is proposed and implemented, for three different PcBN grades, to correlate microstructure with local mechanical properties. A total of 40,000 imprints were performed in each grade. The obtained mechanical maps and data sets are statistically treated following two deconvolution approaches: 1D and 2D Gaussian fitting. The use of high-speed nanoindentation is validated not only by the reliable assessment of the intrinsic mechanical properties of cBN particles, binder and interphase region, but also by the successful mirroring of microstructural assemblage within the mechanical maps attained. Comparison of the results determined from 1D and 2D gaussian representations are in satisfactory agreement. Nevertheless, some difficulties and disparity between them arises when involving fine-grained microstructures. • Mechanical property maps replicate the microstructure assemblage of PcBN grades. • 1D and 2D representations also depict multiphase material microstructure. • Nanoindentation is validated for assessing H and E of PcBN constitutive phases. • Good agreement is generally found between 1D and 2D statistical analysis results. • Demonstration of the presence of a third composite-like/interface-related phase.

Plasmonic biosensor based on metal antenna on graphene for detection and counting of nanoparticles

Plasmons in graphene present desirable electronic properties and unique opportunities to enhance light–matter interactions and control light at nanoscale dimensions. The combination of graphene with metal nanostructures is promising for optical science and plasmonic manipulations. We propose a graphene plasmonic system based on a resonant metal antenna for detection and counting of nanoparticles. The performance of the proposed system relies on the intrinsic properties of particles, including the refractive index, which can be used to modulate the transmitted power. Simulations show that, by a small change in the refractive index of the particle, the transmitted output power changes significantly. A local change of ±10% in the refractive index of a 50-nm dielectric particle around the nanopore results in a ∓2.3% variation in the transmitted power corresponding to a sensor sensitivity of 415 nm/RIU. Small particles with a diameter of 20 ​nm can be detected using this configuration. The placement of a nanopore and nanoparticle in front of the metal antenna can change the spatial near-filed distribution of graphene plasmons and control their propagation wavefronts. Furthermore, the proposed structure with its small footprint can be readily integrated into lab-on-a-chip devices for practical biosensing applications. This plasmonic device is promising for use in single-particle detection and biological applications.

Microstructural evolution and thermal fatigue damage mechanism of second-phase dispersion strengthened tungsten composites under repetitive thermal loads

• After repetitive thermal loads, the ODS/CDS-W composites experience obvious grain growth and particles shedding, leading to a decrease in mechanical properties. • The interface debonding and progressive shedding of second-phase particles from the W matrix is the main reason for the cracks along the grain boundaries. • The W-ZrC composite exhibits a better thermal shock resistance than W-Y 2 O 3 due to the intrinsic properties of second particles. In a fusion reactor, plasma-facing tungsten (W) materials inevitably suffer severe thermal shock, and the performance of W materials under repetitive high heat loads is one of the key concerns for long-term stable operation of the reactor. In this work, the microstructural evolution and thermal fatigue resistance of two representative W-0.5 wt.% ZrC (WZC) and W-1.0 wt.% Y 2 O 3 (WYO) composites were investigated under cyclic heat loads. Due to the intrinsic properties of ZrC and Y 2 O 3 particles such as coefficients of thermal expansion, particle size and distributions in W grains, the WZC composite exhibited a better thermal shock resistance than WYO. After thermal loads with the absorbed power density (APD) ≥ 22 MW/m 2 , WYO showed obvious grain growth, Y 2 O 3 particles shedding and degradation of mechanical properties. While, in the case of WZC, these damage behaviors only occurred when APD ≥ 25 MW/m 2 . Furthermore, an interesting crack mechanism in W composites was revealed due to interface debonding and progressive shedding of second-phase particles from the W matrix. The microstructures and tensile properties of the thermally loaded WZC and WYO specimens were also investigated and the correlations between the microstructure evolution and performance degradation are demonstrated. The results are useful for evaluating the thermal fatigue resistance of oxide/carbide dispersion strengthened W composites and their application in future fusion reactors.

A Methodology to Determine the Potential for Particulate Ore Sorting Based on Intrinsic Particle Properties

Sensor-based particulate ore sorting is a pre-concentration technique that sorts particles based on measurable physical properties, resulting in reduced energy consumption by removing waste prior to grinding. This study presents an integrated methodology to determine the potential for ore sorting based on intrinsic particle properties. The methodology first considers the intrinsic sortability based on perfect separation. Only intrinsically sortable ore is further assessed by determining the sensor-based sortability. The methodology is demonstrated using a case study based on a typical copper porphyry comminution circuit. The sorting duty identified for the case study was the removal of low-grade waste material from the pebble crusher stream at a suitable Cu cut-off grade. It was found that the ore had the potential to be sorted based on the intrinsic and ideal laboratory sensor sortability results but showed no potential to be sorted using industrial-scale sensors. The ideal laboratory XRF sensor results showed that around 40% of mass could be rejected as waste at copper recoveries above 80%. An economic analysis of the sortability tests showed that, at optimum separation conditions, the intrinsic, ideal sensor and industrial sensor sortability would result in an additional annual profit of ~$30 million, $21 million and $−7 million (loss), respectively.

Anisotropy in small-strain shear modulus of granular materials: Effects of particle properties and experimental conditions

Granular soils display directional diversity in stiffness at small strains, which is essential for geotechnical engineering design and can be reflected by the anisotropy of small-strain shear modulus G0. However, the understanding of the stiffness anisotropy of soils is still limited. This contribution presents a series of shear (S-) wave propagation tests using cubical specimens and planer piezoelectric transducers, and discusses the effects of the intrinsic particle properties and experimental conditions on the G0 anisotropy. Four granular materials: spherical glass beads, Toyoura sand, basmati rice, and wild rice are prepared densely in a dry condition and tested under both K0 and isotropic stress states. The experimental results reveal that the particle shape and particle orientation after deposition can affect the anisotropy of the S-wave velocities (Vs), and thus, G0. Tests with different granular materials show that a more elongated particle shape can induce larger anisotropy in G0. From the results of tests on the wild rice specimens, Vs is found to be higher when the major axes of the particles coincide with the direction of the wave propagation, compared to the situation when the major axes are parallel to the oscillation direction of the S-wave. Among the six components in the principal directions, the S-waves neither propagating nor oscillating along the particle orientation are the slowest. Considering the experimental conditions, a mix of flexible (membrane) and rigid boundaries tends to induce larger anisotropy in G0 and a measurable difference between symmetric shear moduli Ghv and Gvh, while the effect of the specimen aspect ratio is less significant.

The Full Multi: An open-source framework for modelling the transport and fate of nano- and microplastics in aquatic systems

We present a freely available open-source modelling framework to explore environmental transport and fate of nano-and microplastics in aquatic systems. The “Full Multi” models 1) fragmentation of plastic into a predefined set of size classes, 2) speciation of plastic particles between pristine, heteroaggregated, biofouled, and biofouled & heteroaggregated species, 3) dynamic vertical exchange between water layers and sediment of a freshwater system, and 4) horizontal particle transport by eddy diffusion and advective flow. The Full Multi framework relates emission rates to environmental exposure concentrations while considering the intrinsic properties of plastic particles and variable environmental system properties. The model can be applied to analyse scenarios with different process descriptions, plastic types, emission routes and environmental parameters for hypothesis generation, to identify dominant fate processes, and in hazard and risk assessment. Here, we introduce and illustrate the framework by modelling plastic particles with a range of densities in a generic flowing river system.

Back Cover: Teaching new tricks to old dogs: A review of drug repositioning of disulfiram for cancer nanomedicine (View 4/2021)

The back cover page of article number 20200076, Gungun Lin displays that the intrinsic magneto-physical properties of magnetic particles can be explored to enable multidimensional cellular phenotyping and biomolecular analysis.

Investigation on B-Site Exsolved Titanates and its Structure-Property Relationship as Fuel Electrode in Solid Oxide Cells

Titanates capable of exsolving B-site metals have shown great potential as fuel electrode in solid oxide cells (SOCs). The well-anchored nano-particles are found to exhibit superior electrocatalytic activity and resistance towards carbon deposition. Here, in order to investigate the intrinsic properties of exsolved particles under redox conditions, we selected La0.43Ca0.37Ni0.06Ti0.94O3-δ (LCNT), La0.43Ca0.37Ni0.03Fe0.03Ti0.94O3-δ (LCNFT), and La0.8Ce0.1Ni0.4Ti0.6O3 (LCeNT) as model electrode materials to exsolve Ni, Ni-Fe alloy, and Ni-CeO2, respectively. The influence of co-doping, doping level, and A-site deficiency on the exsolution process and the behavior of the exsolved particles upon oxidation were studied and characterized. The results suggest that all three materials exsolved nano-particles after reduction with different size and population, yet they tend to follow a similar trend upon oxidation.

NTCP Modeling of Late Effects for Head and Neck Cancer: A Systematic Review.

NTCP Modeling of Late Effects for Head and Neck Cancer: A Systematic Review.

Scalable and paint-format microparticle–polymer composite enabling high-performance daytime radiative cooling

Radiative cooling, a process in which the Earth maintains a near-constant temperature despite significant solar flux, is a promising technology with no requirement of any input energy for sub-ambient cooling as well as no emission of greenhouse gas. Here, we demonstrate a paint-format microparticle–polymer composite with a low fabrication cost, simple structure, and high radiative cooling performance. Harnessing intrinsic optical properties of aluminum oxide and silicon oxide particles with large energy bandgaps and complementary IR emission properties within the atmospheric transparency window, the proposed radiative cooling paint has an extremely low solar absorptivity of 0.032 and strong IR emission of 0.935 in the atmospheric transparency window. Furthermore, many outdoor measurements proved the RC paint provided high-performance radiative cooling effect for comparison with commercial white paint even in hot summer season detrimental for daytime raditaive cooling, enabling the practical use of radiative cooling.

A Binary Particle Self-Assembly Sintering Method to Realize Controllable Synthesis of Fine-Grained Barium Titanate Ceramics

Controllable synthesis of fine-grained dense ceramics still presents great challenges. Here we have developed a binary particle self-assembly sintering method for controllably synthesizing barium titanate (BaTiO3) fine-grained dense ceramics conveniently, by utilizing the intrinsic properties of particles including different size and sintering activity. Under the basic prerequisite for a matching size of the BaTiO3 particles, the particle ratios are a significant factor affecting the grain size and density. Considering the objective of achieving fine-grained dense ceramics, the ceramics with grain size of 252 nm and relative density of 0.92 can be obtained via sintering the two matching size particles with a ratio of 1:1 at 1000°C for 10 h. This means that given size matched particles, we can obtain the dense ceramics with grain size approximately equaling that of large particles (200 nm). Furthermore, sintering aids and special sintering equipment are never required.

Kinetics and mechanism analysis for the photodegradation of PFOA on different solid particles

Perfluorooctanoic acid (PFOA) has attracted considerable attention due to its worldwide distribution, bioaccumulation potential, environmental persistence, and possible toxic effects. In this work, the photodegradation kinetics and mechanisms of PFOA on six different solid particles were investigated. After 24 h of Hg lamp irradiation, significant degradation of PFOA was observed on paddy soil (PS), black soil (BS), yellow soil (YS), red soil (RS), Jiuxiang river soil (JXR) and 400 mesh quartz sand (QS). The photodegradation of PFOA on solid matrixes all followed pseudo-first-order kinetics, and the order of PFOA loss was QS > RS > JXR > YS > BS > PS. The intrinsic properties of solid particles, including light-shielding effect, organic carbon contents, particle size distribution and fractal dimension, and silica contents all have some correlations with PFOA photodegradation. In addition, trifluoroacetic acid (TFA) on solid particles can be effectively photodegraded, while it was hardly degraded in aqueous solution. Mass spectrometry results showed that decarboxylation and elimination were the two main reactions for PFOA photodegradation, leading to the formation of various products. This study may help deepen our understanding on the photochemical behaviors of PFOA on solid particles, which are important to evaluate the environmental fate of PFOA in the air.

A review of polystyrene bead manipulation by dielectrophoresis.

Exploitation of the intrinsic electrical properties of particles has recently emerged as an appealing approach for trapping and separating various scaled particles. Initiative particle manipulation by dielectrophoresis (DEP) showed remarkable advantages including high speed, ease of handling, high precision and being label-free. Herein, we provide a general overview of the manipulation of polystyrene (PS) beads and related particles via DEP; especially, the wide applications of these manipulated PS beads in the quantitative evaluation of device performance for model validation and standardization have been discussed. The motion and polarizability of the PS beads induced by DEP were analyzed and classified into two categories as positive and negative DEP within the time and space domains. The DEP techniques used for bioparticle manipulation were demonstrated, and their applications were conducted in four fields: trapping of single-sized PS beads, separation of multiple-sized PS beads by size, separation of PS beads and non-bioparticles, and separation of PS beads and bioparticles. Finally, future perspectives on DEP-on-a-chip have been proposed to discriminate bio-targets in the network of microfluidic channels.

Estimation of Intrinsic Magnetic Properties of Single Particles by Particle Tracking Velocimetry

Characterization of paramagnetic particles is of utmost importance in biotechnology, cell separations, and medical applications. The particle size uniformity and colloidal stability of paramagnetic particles have been the focus of most producers, but magnetization is never specified and is typically mentioned only in terms of percent iron oxide content. Bulk measurements of magnetic susceptibility and saturation magnetization, using a superconducting quantum interference device (SQUID) or a vibrating sample magnetometer (VSM), provide an average value at best and do not account for the distributed nature of these variables or for particles with zero or very low susceptibility and magnetization. By means of particle tracking velocimetry in dark-field illumination, we measured multiple characteristics of several thousand individual micrometer-sized particles per sample. The Hyperflux velocimeter is utilized to provide quantitative video analysis of cells and particles using a high-definition camera to capture the images of the particle trajectories in an isodynamic field. Image analysis software converts the image data to the parameters of interest based on velocimetry calculations. The intrinsic magnetic properties of the magnetic beads estimated by both the velocimeter and VSM are in good agreement. Estimation of the magnetophoretic mobility distributions and intrinsic magnetic properties of magnetic microparticles using dark-field particle tracking allows economical and time-efficient magnetic evaluation of a broad range of magnetic particle sizes.

Predicting EMP hazard: Lessons from studies with inhaled fibrous and non-fibrous nano- and micro-particles

Inhalation exposure to elongated cleavage fragments occurring at mineral and rock mining and crushing operations raises important questions regarding potential health effects given their resemblance to fibers with known adverse health effects like amphibole asbestos. Thus, a major goal for establishing a toxicity profile for elongate mineral particles (EMPs) is to identify and characterize a suspected hazard and characterize a risk by examining together results of hazard and exposure assessment. This will require not only knowledge about biokinetics of inhaled EMPs but also about underlying mechanisms of effects induced by retained EMPs. In vitro toxicity assays with predictive power for in vivo effects have been established as useful screening tools for toxicological characterization of particulate materials including EMPs. Important determinants of physiological/toxicological mechanisms are physico-chemical and functional properties of inhaled particulate materials. Of the physico-chemical (intrinsic) properties, size, shape and surface characteristics are well known to affect toxicological responses; functional properties include (i) solubility/dissolution rate in physiological fluid simulants in vitro and following inhalation in vivo; (ii) ROS-inducing capacity in vitro and in vivo determined as specific particle surface reactivity; (iii) bioprocessing in vivo. A key parameter for all is the dose and duration of exposure, requiring to establish exposure-dose-response relationships. Examples of studies with fibrous and non-fibrous particles are discussed to illustrate the relevancy of evaluating extrinsic and intrinsic particle properties for predicting in vivo responses of new particulate materials. This will allow hazard and risk ranking/grouping based on a comparison to toxicologically well-characterized positive and negative benchmarks. Future efforts should be directed at developing and validating new approaches using in vitro (non-animal) studies for establishing a complete risk assessment for EMPs. Further comparative in-depth analyses with analytical and ultra-high resolution technology examining bioprocessing events at target organ sites have proven highly successful to identify biotransformations in target cells at near atomic level. In the case of EMPs, such analyses can be essential to separate benign from harmful ones.

Numerical Investigation of a Novel Wiring Scheme Enabling Simple and Accurate Impedance Cytometry.

Microfluidic impedance cytometry is a label-free approach for high-throughput analysis of particles and cells. It is based on the characterization of the dielectric properties of single particles as they flow through a microchannel with integrated electrodes. However, the measured signal depends not only on the intrinsic particle properties, but also on the particle trajectory through the measuring region, thus challenging the resolution and accuracy of the technique. In this work we show via simulation that this issue can be overcome without resorting to particle focusing, by means of a straightforward modification of the wiring scheme for the most typical and widely used microfluidic impedance chip.

First order reversal curves and intrinsic parameter determination for magnetic materials; limitations of hysteron-based approaches in correlated systems

The generic problem of extracting information on intrinsic particle properties from the whole class of interacting magnetic fine particle systems is a long standing and difficult inverse problem. As an example, the Switching Field Distribution (SFD) is an important quantity in the characterization of magnetic systems, and its determination in many technological applications, such as recording media, is especially challenging. Techniques such as the first order reversal curve (FORC) methods, were developed to extract the SFD from macroscopic measurements. However, all methods rely on separating the contributions to the measurements of the intrinsic SFD and the extrinsic effects of magnetostatic and exchange interactions. We investigate the underlying physics of the FORC method by applying it to the output predictions of a kinetic Monte-Carlo model with known input parameters. We show that the FORC method is valid only in cases of weak spatial correlation of the magnetisation and suggest a more general approach.

Towards improved magnetic fluid hyperthermia: major-loops to diminish variations in local heating.

In the context of using magnetic nanoparticles for heat-mediated applications, the need of an accurate knowledge of the local (at the nanoparticle level) heat generation in addition to the usually studied global counterpart has been recently highlighted. Such a need requires accurate knowledge of the links among the intrinsic particle properties, system characteristics and experimental conditions. In this work we have investigated the role of the particles' anisotropy polydispersity in relation to the amplitude (Hmax) of the AC magnetic field using a Monte Carlo technique. Our results indicate that it is better to use particles with large anisotropy for enhancing global heating, whereas for achieving homogeneous local heating it is better to use lower anisotropy particles. The latter ensures that most of the system undergoes major-loop hysteresis conditions, which is the key-point. This is equivalent to say that low-anisotropy particles (i.e. with less heating capability) may be better for accurate heat-mediated applications, which goes against some research trends in the literature that seek for large anisotropy (and hence heating) values.