Particle Diffusion Research Articles

Effect of diffusion of elements on microstructural, mechanical, and machining characteristics of Al7075/ZnAl4 functionally graded material with and without Ag and Pb interface

The current experimental work uses die casting, a liquid processing method, to create functionally graded material (FGM). To reduce the production of undesired intermetallic compounds, the FGM samples were created both with and without interfacing foil during the procedure. Mechanical properties including impact strength and microhardness were examined throughout the manufactured sample's cross-section. In addition, the interfacial bonding of FGM samples with and without an interacting foil was determined by estimating the shear strength. Analysis of the samples using X-ray diffraction (XRD) and scanning electron microscopy (SEM) reveals the existence of compounds in the sample as well as the diffusion of Al and Zn particles from one side to the other. Compared to the FGM without foil, it is observed that the diffusion rate at the interface is regulated when the foil is present. In addition, it was found that, in contrast to pb foil, the inclusion of Ag foil limited the rate at which particles could move from one side to the other. Additionally, machining investigations are carried out at varying depths on both sides of the sample in the direction of the interface with the assistance of electric discharge machining.

Formulation and dermal delivery of a new active pharmaceutical ingredient in an in vitro wound model for the treatment of chronic ulcers

The aim of this study was to investigate dermal delivery of the new active pharmaceutical ingredient (API) TOP-N53 into diabetic foot ulcer using an in vitro wound model consisting of pig ear dermis and elucidate the impact of drug formulation and wound dressing taking into consideration clinical relevance in the home care setting and possible bacterial infection. Different formulation approaches for the poorly water-soluble API including colloidal solubilization, drug micro-suspension and cosolvent addition were investigated; moreover, the effect of (micro-)viscosity of hydrogels used as primary wound dressing on delivery was assessed. Addition of Transcutol® P as cosolvent to water improved solubility and was significantly superior to all other approaches providing a sustained three-day delivery that reached therapeutic drug levels in the tissue. Solubilization in micelles or liposomes, on the contrary, did not boost delivery while micro-suspensions exhibited sedimentation on the tissue surface. Microbial contamination was responsible for considerable metabolism of the drug leading to tissue penetration of metabolites which may be relevant for therapeutic effect. Use of hydrogels under semi-occlusive conditions significantly reduced drug delivery in a viscosity-dependent fashion. Micro-rheologic analysis of the gels using diffusive wave spectroscopy confirmed the restricted diffusion of drug particles in the gel lattice which correlated with the obtained tissue delivery results. Hence, the advantages of hydrogel dressings from the applicatory characteristic point of view must be weighed against their adverse effect on drug delivery. The employed in vitro wound model was useful for the assessment of drug delivery and the development of a drug therapy concept for chronic diabetic foot ulcer. Mechanistic insights about formulation and dressing performance may be applied to drug delivery in other skin conditions such as digital ulcer.

Diffusion of noiseless active particles in a planar convection array.

We investigated, both analytically and numerically, the dynamics of a noiseless overdamped active particle in a square lattice of planar counter-rotating convection rolls. Below a first threshold of the self-propulsion speed, a fraction of the simulated particle's trajectories spatially diffuse around the convection rolls, whereas the remaining trajectories remain trapped inside the injection roll. We detected two chaotic diffusion regimes: (i) below a second, higher threshold of the self-propulsion speed, the particle performs a random motion characterized by asymptotic normal diffusion. Long superdiffusive transients were observed for vanishing small self-propulsion speeds. (ii) above that threshold, the particle follows chaotic running trajectories with speed and orientation close to those of the self-propulsion vector at injection and its dynamics is superdiffusive. Chaotic diffusion disappears in the ballistic limit of extremely large self-propulsion speeds.

Quaternionic generalization of telegraph equations

Using non-commutative spacetime quaternion algebra, we represent the generalization of one-dimensional and three-dimensional telegraph equations, which are widely applied to consider the propagation of an electromagnetic signal in communication lines, as well as to describe particle diffusion and heat transfer. It is shown that the system of telegraph equations can be represented in compact form as a single quaternion equation taking into account the spacetime properties of physical quantities. The distinctive features of the one-dimensional and three-dimensional telegraph equations are discussed.

Role of particle diffusion in shaping the gravitational wave signal from neutron star inspirals

Role of particle diffusion in shaping the gravitational wave signal from neutron star inspirals

A mat based on PVA doped with TiO2 nanoparticles for removal of methylene blue dye from aqueous solution and improving the carbon footprint.

Water supply is the great challenge for climate change and overpopulation. A Nanofiber mat consisting of Poly vinyl alcohol (PVA), nanoTiO2, and citric acid (PTC) was prepared using an electrospinning technique at a constant flow rate (0.5 ml/h). The morphology of the mat was detected using (FESEM) technique and image J software; they show that the mat has a Nanofiber morphology with an average diameter of 170 nanometers. This mat was used to remove methylene blue (MB) from water in two ways, the adsorption process and by photodegradation using UV light. The kinetic study of the adsorption of methylene blue MB on a PTC mat was carried out. results show that the pseudo-second order is best to describe the adsorption, of MB and the Intra- particle diffusion is the rate determining step. Seven isotherm models; four of two-parameters and three of three-parameters were used to examine the adsorption experimental data by applying linear and non-linear regression method using six error functions. The results showed comparable data between linear and non-linear regression methods for two parameters isotherms, and the best isotherm fitting with the data were Freundlich and Temkin models. On the contrary, three parameters isotherms showed distracted data between linear and non-linear regression methods. In addition, the results appear that the best predictive error function was ꭓ2.

Strain-engineered particle diffusion in uniaxially deformed polymer networks

Precise control of particle diffusion is highly valuable in diverse modern technologies. Traditional methods for regulating particle diffusion are often limited by inherent properties of liquid medium. This study explores mechanical deformation as a new design space to engineer particle diffusion in stretchable soft materials. Combining experimental and theoretical analyses, we discover that particle diffusivity in a uniaxially deformed polymer network is governed by two dimensionless parameters: the ratio of particle size to the polymer network's mesh size and the stretch ratio applied to the polymer network. We further demonstrate a transition in the relationship between particle diffusivity and stretch ratio, characterized by a monotonic decrease for small particles and a non-monotonic trend for large particles. This transition is attributed to the synergistic effects involving geometric transformation of the deformed polymer network and energy modulation of the stretched polymer chains. This work introduces a new mechanism for controlling particle diffusivity in polymeric materials and establishes a theoretical foundation for developing previously inaccessible transport-based technologies.

Exploring optical solitary wave solutions in the (2+1)-dimensional equation with in-depth of dynamical assessment

The current study explores the (2+1)-dimensional Chaffee-Infante equation, which holds significant importance in theoretical physics renowned reaction-diffusion equation with widespread applications across multiple disciplines, for example, ion-acoustic waves in optical fibres, fluid dynamics, electromagnetic wave fields, high-energy physics, coastal engineering, fluid mechanics, plasma physics, and various other fields. Furthermore, the Chaffee-Infante equation serves as a model that elucidates the physical processes of mass transport and particle diffusion. We employ an innovative new extended direct algebraic method to enhance the accuracy of the derived exact travelling wave solutions. The obtained soliton solutions span a wide range of travelling waves like bright-bell shape, combined bright-dark, multiple bright-dark, bright, flat-kink, periodic, and singular. These solutions offer valuable insights into wave behaviour in nonlinear media and find applications in diverse fields such as optical fibres, fluid dynamics, electromagnetic wave fields, high-energy physics, coastal engineering, fluid mechanics, and plasma physics. Soliton solutions are visually present by manipulating parameters using Wolfram Mathematica software, graphical representations allow us to study solitary waves as parameters change. Observing the dynamics of the model, this study presents sensitivity in a nonlinear dynamical system. The applied mathematical approaches demonstrate its ability to identify reliable and efficient travelling wave solitary solutions for various nonlinear evolution equations.

41‐2: A Patterned Packaging Scheme of MiniLED Tiled Display with HighTransmittance and High Color Consistency in Light and Dark States

Tiled display has gradually become the development direction of super large screen display. A high transmittance greater than 80% and visual consistency with ΔE>0.5 in off state and Δu′v′>0.004 between multiple modules in display state MiniLED tiled display packaging scheme was proposed in this paper. The LED on the display substrate was wrapped by the barrier and diffusion particles. In addition, the glass cover plate with stable OD BM pattern is pasted above the display substrate to achieve consistency of blackness between multiple modules, with diamond black effect. This scheme is of great significance to the development of tiled display technology.

The viscoelasticity of high concentration monoclonal antibodies using particle tracking microrheology.

The viscoelasticity of monoclonal antibodies (mAbs) is important during their production, formulation, and drug delivery. High concentration mAbs can provide higher efficacy therapeutics (e.g., during immunotherapy) and improved efficiency during their production (economy of scale during processing). Two humanized mAbs were studied (mAb-1 and mAb-2) with differing isoelectric points. Using high speed particle tracking microrheology, we demonstrated that the mAb solutions have significant viscoelasticities above concentrations of 40 mg/ml. Power law viscoelasticity was observed over the range of time scales (-1 s) probed for the high concentration mAb suspensions. The terminal viscosity demonstrated an exponential dependence on mAb concentration (a modified Mooney relationship) as expected for charged stabilized Brownian colloids. Gelation of the mAbs was explored by lowering the pH of the buffer and a power law scaling of the gelation transition was observed, i.e., the exponent of the anomalous diffusion of the probe particles scaled inversely with the gelation time.

Evolution of some flow-related properties of diffusive aerosols along a tube

This is the third of a series of papers dealing with the behavior of Brownian aerosol particles immersed in a laminar fluid flow. The evolution along the tube of the distributions of particle radial positions (RPD), particle residence time (RTD), and particle mean axial velocity (MAVD) were determined by Monte Carlo (MC) simulation of particles trajectories. The RPD and particle penetration was also determined by numerical solution of the advection-diffusion equation (ADE) with negligible particle axial diffusion. The fairly good agreement shown between the results obtained by these two methods justifies our confidence on the use of the MC technique to determine other particle properties, as MAVD and RTD, for which the corresponding differential equation is yet unknown. Flow-related properties of the aerosol, such as penetration and residence time, are mainly determined by its MAVD. The MAVD is intimately related to the RPD; the latter evolves in such a manner that the surviving particles tend to accumulate nearer the tube axis and farther from the wall. When the fluid local velocity depends on the spatial location, the mean particle axial velocity increases as the aerosol flows downstream the tube, and its value can be considerably larger than the mean fluid velocity, in spite that no external force is acting on the particle. A direct consequence of this counterintuitive fact is that the mean aerosol residence time in the tube can be much smaller, by a factor of ∼0.65, than that of the fluid for even moderate values of the particle diffusion coefficient. This asymptotic value of the aerosol mean residence time can be predicted using the ADE in conjunction with a simple estimation model proposed here. If the fluid velocity is constant within the tube (uniform or plug flow), the mean particle axial velocity is everywhere equal to the fluid velocity, and particles and fluid spend the same time to traverse the tube. The larger the departure of the fluid velocity profile from uniformity, the larger the difference of mean axial velocity and mean residence time between particles and fluid.

Stress-induced diffusion in viscoelastic electrode particles of Li-ion batteries: a comparative analysis using chemo-viscoelastic finite element models

Stress-induced diffusion in viscoelastic electrode particles of Li-ion batteries: a comparative analysis using chemo-viscoelastic finite element models

Sedimentation dynamics of passive particles in dilute bacterial suspensions: emergence of bioconvection

Microorganisms are ubiquitous in nature and technology. They inhabit diverse environments, ranging from small river tributaries and lakes, to oceans, as well as wastewater treatment plants and food manufacturing. In many of these environments, microorganisms coexist with settling particles. Here, we investigate the effects of microbial activity (swimming E. coli) on the settling dynamics of passive colloidal particles using particle tracking methods. Our results reveal the existence of two distinct regimes in the correlation length scale ( $L_u$ ) and the effective diffusivity of the colloidal particles ( $D_{eff}$ ), with increasing bacterial concentration ( $\phi _b$ ). At low $\phi _b$ , the parameters $L_u$ and $D_{eff}$ increase monotonically with increasing $\phi _b$ . Beyond critical $\phi _b$ , a second regime is found where both $D_{eff}$ and $L_u$ are independent of $\phi _b$ . We demonstrate that the transition between these regimes is characterized by the emergence of bioconvection. We use experimentally measured particle-scale quantities $L_u$ and $D_{eff}$ to predict the critical bacterial concentration for the diffusion–bioconvection transition.

Constant speed random particles spontaneously confined on the surface of an expanding sphere

The particles that we describe here can only move at the speed of light c in three-dimensional space. The velocity, which randomly but continuously changes direction, can be represented as a point on the surface of a sphere of constant radius c, and its trajectories may only connect points of this variety. The Wiener process that we use to describe the velocity dynamics on the surface of the sphere is anisotropic since the infinitesimal variation of the velocity is not only always orthogonal to the velocity itself (which guarantees a constant speed), but also to the position. This choice for the infinitesimal variation of the velocity is the one that best slows down the diffusion of particles in space by random motion at the speed of light. As a result of these dynamics, the position of the particles spontaneously remain confined on the surface of an expanding sphere whose radius increases, for large times, as the square root of time.

Focused Ultrasound-Mediated Disruption of the Blood-Brain Barrier for AAV9 Delivery in a Mouse Model of Huntington's Disease.

Huntington's disease (HD) is a monogenic neurodegenerative disorder caused by a cytosine-adenine-guanine (CAG) trinucleotide repeat expansion in the HTT gene. There are no cures for HD, but the genetic basis of this disorder makes gene therapy a viable approach. Adeno-associated virus (AAV)-miRNA-based therapies have been demonstrated to be effective in lowering HTT mRNA; however, the blood-brain barrier (BBB) poses a significant challenge for gene delivery to the brain. Delivery strategies include direct injections into the central nervous system, which are invasive and can result in poor diffusion of viral particles through the brain parenchyma. Focused ultrasound (FUS) is an alternative approach that can be used to non-invasively deliver AAVs by temporarily disrupting the BBB. Here, we investigate FUS-mediated delivery of a single-stranded AAV9 bearing a cDNA for GFP in 2-month-old wild-type mice and the zQ175 HD mouse model at 2-, 6-, and 12-months. FUS treatment improved AAV9 delivery for all mouse groups. The delivery efficacy was similar for all WT and HD groups, with the exception of the zQ175 12-month cohort, where we observed decreased GFP expression. Astrocytosis did not increase after FUS treatment, even within the zQ175 12-month group exhibiting higher baseline levels of GFAP expression. These findings demonstrate that FUS can be used to non-invasively deliver an AAV9-based gene therapy to targeted brain regions in a mouse model of Huntington's disease.

Activity-induced diffusion recovery in crowded colloidal suspensions.

We show that the forces generated by active enzyme molecules are strong enough to influence the dynamics of their surroundings under artificial crowded environments. We measured the behavior of polymer microparticles in a quasi-two-dimensional system under aqueous environment, at various area fraction values of particles. In the presence of enzymatic activity, not only was the diffusion of the suspended particles enhanced at shorter time-scales, but the system also showed a transition from subdiffusive to diffusive dynamics at longer time-scale limits. Similar observations were also recorded with enzyme-functionalized microparticles. Brownian dynamics simulations have been performed to support the experimental observations.

Mass Interaction Principle as a Foundational Framework for Quantum Mechanics

This paper proposes mass interaction principle (MIP) as: the particles will be subjected to the random frictionless Brownian motion by the collision of space time particle(STP) ubiquitous in spacetime. The change in the amount of action of the particles during each collision is an integer multiple of the Planck constant h. The motion of particles under the action of STP is a Markov process. Under this principle, we infer that the statistical inertial mass of a particle is a statistical property that characterizes the difficulty of particle diffusion in spacetime. Within the framework of MIP, all the essences of quantum mechanics are derived, which proves that MIP is the origin of quantum mechanics. Due to the random collisions between STP and the matter particles, matter particles are able to behave exactly as required by the supervisor and shepherd for all microscopic behaviors of matter particles. More importantly, we solve a world class puzzle about the anomalous magnetic moment of muon in the latest experiment,and give a self-consistent explanation to the lifetime discrepancy of muon between standard model prediction and experiments at the same time. Last but not least, starting from MIP, we prove the principle of entropy increasing and clarify the physical root of entropy at absolute zero. Within the framework of MIP, we comprehensively discussed the Copenhagen interpretation. It leads to an important conclusion that Copenhagen interpretation is unnecessary for the quantum mechanical system. We found that Maxwell’s classical electromagnetic theory is applicable to the microscopic world not as previously thought. The key is that Brownian motion and classical electromagnetic theory must be combined together to completely solve the problem of electrons outside the nucleus not radiating electromagnetic waves.

Intelligent neural computing to investigate the heat and mass transmission in nanofluidic system between two rotating permeable disks: Supervised learning mechanism

The prime objective of the present study is to investigate the effectiveness and accuracy of a single-trained artificial neural network. The Levenberg-Marquardt Backpropagated networks are tested for heat and mass transmission in magnetized hybrid nanofluid flow between the rotating permeable system. The reference data to generate different cases for distinct scenarios has been obtained using the Adams method in Mathematica using the ND-Solver function. Additionally, the system of highly nonlinear PDE's is achieved and transformed into ODE's. The effect of body forces such as thermophoresis particle diffusion and Brownian motion are incorporated in the hybrid nanofluid system. Configuration under observation is permeable and under constant impact of the magnetic field. Rosseland thermal radiation approximation relation is utilized to investigate the linear impact of radiation on velocity and temperature profile. The accuracy and effectiveness of the proposed ANNLMB are depicted with performance demonstrations. Mean square error, histogram error, and regression plots are generated for all the scenarios to discuss the varying impact of different key study parameters on the performance of the proposed ANNLMB. Furthermore, the generated reference data is distributed in the following manner 82 %, 9 %, and 9 % for training, testing, and validation, respectively.

Large-population asymptotics for the maximum of diffusive particles with mean-field interaction in the noises

We study the N→∞ limit of the normalized largest component in some systems of N diffusive particles with mean-field interaction. By applying a universal time change, the interaction in noises is transferred to the drift terms, and the asymptotic behavior of the maximum becomes well-understood due to existing results in the literature. We expect that the normalized maximum in the original setting has the same limiting distribution as that of i.i.d copies of a solution to the corresponding McKean–Vlasov SDE and we present some results and numerical simulations that support this conjecture.

Entropic stochastic resonance of finite-size particles in confined Brownian transport.

We demonstrate the existence of entropic stochastic resonance (ESR) of passive Brownian particles with finite size in a double- or triple-circular confined cavity, and compare the similarities and differences of ESR in the double-circular cavity and triple-circular cavity. When the diffusion of Brownian particles is constrained to the double- or triple-circular cavity, the presence of irregular boundaries leads to entropic barriers. The interplay between the entropic barriers, a periodic input signal, the gravity of particles, and intrinsic thermal noise may give rise to a peak in the spectral amplification factor and therefore to the appearance of the ESR phenomenon. It is shown that ESR can occur in both a double-circular cavity and a triple-circular cavity, and by adjusting some parameters of the system, the response of the system can be optimized. The differences are that the spectral amplification factor in a triple-circular cavity is significantly larger than that in a double-circular cavity, and compared with the ESR in a double-circular cavity, the ESR effect in a triple-circular cavity occurs within a wider range of external force parameters. In addition, the strength of ESR also depends on the particle radius, and smaller particles can induce more obvious ESR, indicating that the size effect cannot be safely neglected. The ESR phenomenon usually occurs in small-scale systems where confinement and noise play an important role. Therefore, the mechanism that is found could be used to manipulate and control nanodevices and biomolecules.