Probability Of Coalescence Research Articles

Searching for enhancement in coalescence of in-jet (anti-)deuterons in proton-proton collisions

Recent measurements from ALICE report that “in-jet” nucleons carry a higher probability of forming a deuteron via coalescence than the nucleons from the underlying event (UE). This study makes use of an event shape classifier to separate the “in-jet” deuterons and the deuterons in the UE produced in high multiplicity proton-proton collisions at s=13 TeV. Event shape variables such as transverse spherocity allow the categorization of hard and soft components of an event, which can be divided into two respective classes; “jetty” and “isotropic”. The “jetty” deuterons minus the contribution of the deuterons from the “isotropic” event are taken as “in-jet” deuterons, and the coalescence mechanism is tested. The coalescence is performed with a Wigner function formalism, augmented as an afterburner to . The possible enhancement of the coalescence probability of “in-jet” deuterons is investigated by calculating the coalescence parameter (B2) in different spherocity classes in high-multiplicity pp collisions. Published by the American Physical Society 2024

Study on stabilized mechanism of high internal phase Pickering emulsions based on commercial yeast proteins: Modulating the characteristics of Pickering particle via sonication

The primary significance of this work is that the commercial yeast proteins particles were successfully used to characterize the high internal phase Pickering emulsions (HIPPEs). The different sonication time (0,3,7,11,15 min) was used to modulate the structure and interface characteristics of yeast proteins (YPs) that as Pickering particles. Immediately afterward, the influence of YPs particles prepared at different sonication time on the rheological behavior and coalescence mechanism of HIPPEs was investigated. The results indicate that the YPs sonicated for 7 min exhibited a more relaxed molecular structures and conformation, the smallest particle size, the highest H0 and optimal amphiphilicity (the three-phase contact (θ) was 88.91°). The transition from extended to compact conformations of YPs occurred when the sonication time exceeded 7 min, resulting in an augmentation of size of YPs particles, a reduction in surface hydrophobicity (H0), and an elevation in hydrophilicity. The HIPPEs stabilized by YPs particles sonicated for 7 min exhibited the highest adsorption interface protein percentage and a more homogeneous three-dimensional (3D) protein network, resulting in the smallest droplet size and the highest storage (G′). The HIPPEs sample that stabilized by YPs particles sonicated for 15 min showed the lowest adsorption protein percentage. This caused a reduction in the thickness of its interface protein layer and an enlargement in the droplet diameter (D [3,2]). It was prone to droplet coalescence according to the equation used to evaluate the coalescence probability of droplets (Eq (2)). And the non-adsorbed YPs particles form larger aggregation structures in the continuous phase and act as “structural agents” in 3D protein network. Therefore, mechanistically, the interface protein layer formed by YPs particles sonicated 7 min contributed more to HIPPEs stability. Whereas the “structural agents” contributed more to HIPPEs stability when the sonication time exceeded 7 min. The present results shed important new light on the application of commercial YPs in the functional food fields, acting as an available and effective alternative protein.

Bursts of coalescence within population pedigrees whenever big families occur.

We consider a simple diploid population-genetic model with potentially high variability of offspring numbers among individuals. Specifically, against a backdrop of Wright-Fisher reproduction and no selection, there is an additional probability that a big family occurs, meaning that a pair of individuals has a number of offspring on the order of the population size. We study how the pedigree of the population generated under this model affects the ancestral genetic process of a sample of size two at a single autosomal locus without recombination. Our population model is of the type for which multiple-merger coalescent processes have been described. We prove that the conditional distribution of the pairwise coalescence time given the random pedigree converges to a limit law as the population size tends to infinity. This limit law may or may not be the usual exponential distribution of the Kingman coalescent, depending on the frequency of big families. But because it includes the number and times of big families, it differs from the usual multiple-merger coalescent models. The usual multiple-merger coalescent models are seen as describing the ancestral process marginal to, or averaging over, the pedigree. In the limiting ancestral process conditional on the pedigree, the intervals between big families can be modeled using the Kingman coalescent but each big family causes a discrete jump in the probability of coalescence. Analogous results should hold for larger samples and other population models. We illustrate these results with simulations and additional analysis, highlighting their implications for inference and understanding of multilocus data.

Comparative study on the performance and properties of polyether and polyacrylate crude oil demulsifier

ABSTRACT Polyacrylate crude oil demulsifier is one of the hot topics in the research and development of demulsifier at present, there is a lack of systematic comparative study on performance and properties of polyether and polyacrylate crude oil demulsifier. In this paper, the demulsification performance and microscopic demulsification process of the two demulsifiers, namely polyacrylate P(MA-DBC) and polyether P199–59 are discussed. The demulsification performance of polyether P199–59 was superior to that of polyacrylate P(MA-DBC). The study of the microscopic process of demulsification established that for P199–59, the diffusion rate was faster, the saturated adsorption capacity was higher, the ability to destroy the oil-water interface film was stronger and the probability of water droplets collision coalescence was higher; therefore, it can achieve faster dehydration speed and higher dehydration rate than that of P(MA-DBC). The results of this comparative study are meaningful for improving the demulsification performance of polyacrylate demulsifier.

Explainable AI models for predicting drop coalescence in microfluidics device

In the field of chemical engineering, understanding the dynamics and probability of drop coalescence is not just an academic pursuit, but a critical requirement for advancing process design by applying energy only where it is needed to build necessary interfacial structures, increasing efficiency towards Net Zero manufacture. This research applies machine learning predictive models to unravel the sophisticated relationships embedded in the experimental data on drop coalescence in a microfluidics device. Through the deployment of SHapley Additive exPlanations values, critical features relevant to coalescence processes are consistently identified. Comprehensive feature ablation tests further delineate the robustness and susceptibility of each model. Furthermore, the incorporation of Local Interpretable Model-agnostic Explanations for local interpretability offers an elucidative perspective, clarifying the intricate decision-making mechanisms inherent to each model’s predictions. As a result, this research provides the relative importance of the features for the outcome of drop interactions. It also underscores the pivotal role of model interpretability in reinforcing confidence in machine learning predictions of complex physical phenomena that are central to chemical engineering applications.

Enhanced Deuteron Coalescence Probability in Jets.

The transverse-momentum (p_{T}) spectra and coalescence parameters B_{2} of (anti)deuterons are measured in p-p collisions at sqrt[s]=13 TeV for the first time in and out of jets. In this measurement, the direction of the leading particle with the highest p_{T} in the event (p_{T}^{lead}>5 GeV/c) is used as an approximation for the jet axis. The event is consequently divided into three azimuthal regions, and the jet signal is obtained as the difference between the toward region, that contains jet fragmentation products in addition to the underlying event (UE), and the transverse region, which is dominated by the UE. The coalescence parameter in the jet is found to be approximately a factor of 10 larger than that in the underlying event. This experimental observation is consistent with the coalescence picture and can be attributed to the smaller average phase-space distance between nucleons in the jet cone as compared with the underlying event. The results presented in this Letter are compared to predictions from a simple nucleon coalescence model, where the phase-space distributions of nucleons are generated using pythia8 with the Monash 2013 tuning, and to predictions from a deuteron production model based on ordinary nuclear reactions with parametrized energy-dependent cross sections tuned on data. The latter model is implemented in pythia8.3. Both models reproduce the observed large difference between in-jet and out-of-jet coalescence parameters, although the almost flat trend of the B_{2}^{Jet} is not reproduced by the models, which instead give a decreasing trend.

Positronium hydride decay into proton, electron, and one or zero photons

Decay rates of the positronium hydride PsH, a bound state of a proton, a positron, and two electrons, are determined for two rare channels, $\text{PsH}\ensuremath{\rightarrow}{p}^{+}{e}^{\ensuremath{-}}\ensuremath{\gamma}$ and $\text{PsH}\ensuremath{\rightarrow}{p}^{+}{e}^{\ensuremath{-}}$. Previous studies overestimated these rates by factors of about 2 and 700, respectively. We explain the physics underlying these wrong predictions. We confirm a range of static PsH properties, including the nonrelativistic ground-state energy, expectation values of interparticle distances and their powers, and the three- and four-particle coalescence probabilities, using a variational method in the Gaussian basis.

On 1-point densities for Arratia flows with drift

We show that if drift coefficients of Arratia flows converge in or then the 1-point densities associated with these flows converge to the density for the flow with the limit drift. The main result is proven by providing a representation of the probability of coalescence in the flow as a solution to a PDE and applying the perturbation theory.

Binary Collisions of Water Drops in Presence of Horizontal Electric Fields: A Wind Tunnel Study

AbstractCoalescence/breakup characteristics of binary collisions of small water drops (dS = 0.4–1.8 mm diameter) with large drops (dL = 3–3.5 mm diameter) occurring in the absence/presence of horizontal electric field (EH) = 0, 100, and 300 kVm−1 have been investigated in a small vertical wind tunnel using a high‐speed digital camera. The coalescence efficiency (EC) of 0.299 observed for average diameters (dL = 3.2 mm, dS = 1.2 mm) in EH = 0 decreased to 0.244/0.211 when EH is increased to 100/300 kVm−1. The increase in the electric field reduces the probability of coalescence when Weber number (We) < 1. However, when We ≥ 1, an increase in We restricts the probability of coalescence. Our data, when plotted in the regime diagram in the We*‐p plane, delineates the collision outcomes in all‐electric field values but does show the overlapping of some data points in the adjacent categories. After a binary collision, the relaxation time for coalescence is higher than that for the breakup. Further, the relaxation time increases from the filament to sheet to disk mode of breakup in all‐electric field values. Fragment size distributions after the filament and sheet types of breakups differ and are differently affected by the applied electric field. Higher collision kinetic energy has a tendency to increase the number of fragments of the sizes between dL and dS. It is concluded therefore that, the effect of the electric field needs to be included in the estimation of drop growth and precipitation in clouds.

Single bubble probe atomic force microscope and impinging-jet technique unravel the interfacial interactions controlled by long chain fatty acid in anaerobic digestion

Anaerobic digestion of lipid-rich wastewater generally suffers from foaming induced by long chain fatty acid (LCFA). However, a systematic understanding of LCFA inhibition, especially the physical inhibition on interfacial interaction still remains unclear. Here, we combined bubble probe atomic force microscope and impinging-jet technique to unravel the interfacial interactions controlled by long chain fatty acids in anaerobic digestion. We showed that LCFA had a significant inhibition on methane production in anaerobic reactors for the inhibition of the conversion of VFAs to methane. By measuring the LCFA influence on methanogenic archaea Methanosarcina acetivorans C2A, the results demonstrated that methanogenesis was limited for substrates utilization but not metabolic pathways. The impinging-jet technique results indicated that LCFA enhanced bubble separation from anaerobic granules and reduced the bubble-bubble coalescence probability. In addition, the bubble probe atomic force microscope (AFM) revealed that LCFA enhanced the adhesion force between bubbles by enhancing electrical double layer (EDL) repulsion and decreasing hydrophobic interactions. Overall, these results complement framework of LCFA inhibition in anerobic digestion and provide a nanomechanical insight into the fundamental interfacial interactions related to bubbles in anaerobic reactors.

A bubble coalescence kernel combining the characteristics of the film drainage, energy, and critical velocity models

A novel coalescence kernel with high predictive properties is constructed to be used within the population balance framework. The kernel includes the product of a collision frequency term and a novel binary coalescence probability expression. The probability expression employs critical velocity estimations from film drainage simulations that also considers particle surface and kinetic energies. Thus, the proposed expression possesses characteristics of all three commonly used approaches: film drainage, energy, and critical velocity models. The probability of a collision having a certain velocity and angle is considered through probability density functions while adapting to the Eulerian frame. A maximum collision angle that allows coalescence is defined. The kernel is free of artificially introduced tuning parameters and predicts the size distributions in bubbly pipe flow experiments exceptionally well, including complex behaviors such as emergence of secondary peaks in the distribution. The theory presented is equally valid for bubbles and droplets.

Asymptotic Gaussianity via coalescence probabilities in the Hammond-Sheffield urn

For the renormalised sums of the random $\pm 1$-colouring of the connected components of $\mathbb Z$ generated by the coalescing renewal processes in the "power law P\'olya's urn" of Hammond and Sheffield we prove functional convergence towards fractional Brownian motion, closing a gap in the tightness argument of their paper. In addition, in the regime of the strong renewal theorem we gain insights into the coalescing renewal processes in the Hammond-Sheffield urn (such as the asymptotic depth of most recent common ancestors) and are able to control the coalescence probabilities of two, three and four individuals that are randomly sampled from $[n]$. This allows us to obtain a new, conceptual proof of the asymptotic Gaussianity (including the functional convergence) of the renormalised sums of more general colourings, which can be seen as an invariance principle beyond the main result of Hammond and Sheffield. In this proof, a key ingredient of independent interest is a sufficient criterion for the asymptotic Gaussianity of the renormalised sums in randomly coloured random partitions of $[n]$, based on Stein's method. Along the way we also prove a statement on the asymptotics of the coalescence probabilities in the long-range seedbank model of Blath, Gonz\'alez Casanova, Kurt, and Span\`o.

Spray characterization in a multi-jet airblast injector with swirling air crossflow

Experimental spray characterization in a multi-jet airblast injector with swirling crossflow of air is the goal of the present work. The current injector allows radial injection of six liquid jets from a central hub into swirling and crossflowing air into the annular region around the hub. In the present study, three different aspects related to jet-in-crossflow are concurrently addressed viz. air flow confinement, air swirl and simultaneous atomization of multiple liquid jets. Such key features have been rarely reported in the past in spite of their relevance to practical injectors such as in Lean Premixed Prevaporized (LPP) gas turbine combustors. The spray structure and spatial distribution of droplets are visualized at different cross-sectional planes in the spray by application of the Laser Sheet Imaging (LSI) technique. The Droplet size, three components of droplet velocities and local liquid mass flux are measured at different axial and radial locations using the Phase Doppler Particle Analyzer (PDPA) technique. The injector is operated over a wide range of aerodynamic Weber number (Weg) of the liquid jets (Weg = 57 – 430). The physics behind the spatial evolution of characteristic droplet size is analyzed by estimating the droplet Weber number and the probability of droplet coalescence. The plume-to-plume interaction, subsequent to droplet generation from the primary atomization of adjacent liquid jets, is found to contribute to the variation of droplet size in the current injector. The influence of Weg on the evolution of spray characteristics is investigated in detail.

Metal Nanocatalyst Sintering Interrogated at Complementary Length Scales.

Metal nanoparticle (NP) sintering is a prime cause of catalyst degradation, limiting its economic lifetime and viability. To date, sintering phenomena are interrogated either at the bulk scale to probe averaged NP properties or at the level of individual NPs to visualize atomic motion. Yet, "mesoscale" strategies which bridge these worlds can chart NP populations at intermediate length scales but remain elusive due to characterization challenges. Here, a multi-pronged approach is developed to provide complementary information on Pt NP sintering covering multiple length scales. High-resolution scanning electron microscopy (HRSEM) and Monte Carlo simulation show that the size evolution of individual NPs depends on the number of coalescence events they undergo during their lifetime. In its turn, the probability of coalescence is strongly dependent on the NP's mesoscale environment, where local population heterogeneities generate NP-rich "hotspots" and NP-free zones during sintering. Surprisingly, advanced in situ synchrotron X-ray diffraction shows that not all NPs within the small NP sub-population are equally prone to sintering, depending on their crystallographic orientation on the support surface. The demonstrated approach shows that mesoscale heterogeneities in the NP population drive sintering and mitigation strategies demand their maximal elimination via advanced catalyst synthesis strategies.

Effect of Operating Parameters on the Coalescence and Breakup of Bubbles in a Multiphase Pump Based on a CFD-PBM Coupled Model

When the multiphase pump is running, the internal medium often exists as bubble flow. In order to investigate the bubble occurrence characteristics in the pressurization unit of the multiphase pump more accurately, this paper couples computational fluid dynamics (CFD) with a population balance model (PBM) to investigate the bubble size distribution law of the multiphase pump under different operating conditions, taking into account the bubble coalescence and breakup. The research shows that the mean bubble size in the impeller domain gradually decreases from 1.7013 mm at the inlet to 0.6179 mm at the outlet along the axis direction; the average bubble diameter in the diffuser domain fluctuates around 0.60 mm. The bubbles in the impeller region gradually change from the trend of coalescence to the trend of breakup along the axial and radial directions, and the bubbles in the diffuser tend to be broken by the vortex entrainment. The bubble size development law is influenced by the inlet gas volume fraction (IGVF) and the rotational speed, showing a more obvious rule, where the gas phase aggregation phenomenon enhanced by the increase in IGVF promotes the trend of bubble coalescence and makes the bubble size gradually increase. The increased blade shearing effect with the increase in rotational speed promotes the trend of bubble breakup, which gradually reduces the size of the bubbles. In addition, increasing the bubble coalescence probability is a key factor leading to changes in bubble size; the bubble size development law is not very sensitive to changes in flow, and the bubble size is at its maximum under design conditions. The research results can accurately predict the performance change of the multiphase pump and provide technical guidance for its safe operation and optimal design.

Bubble behavior under a novel metallurgy process coupling an annular gas curtain with swirling flow at tundish upper nozzle

A novel metallurgy process coupling an annular gas curtain and swirling flow technology at a tundish upper nozzle (TUN) was developed in this paper. The migration and distribution behaviors of bubbles were studied by a 1:2 scale water model, and the effects of the process and structural parameters on the distribution of gas flow and bubble size in the mold were further investigated. The results indicated that most argon bubbles float up in the tundish, forming a complete annular gas curtain around the stopper rod, and a small portion of small bubbles enter the nozzle and mold, which can realize the effect of normal argon blowing at the TUN. The liquid steel passing through the swirl slots can produce a certain swirling flow in the nozzle. Under the action of the centrifugal force of the swirling flow, lightweight bubbles will converge to the centre of the nozzle, which increases the collision and coalescence probability of bubbles. As the flow rate of argon blowing, casting speed, and number and height of swirl slots increase, the argon volume and average bubble size in the mold gradually increase.

[formula omitted] formation from random charm and anti-bottom quarks in the quark-gluon plasma

We study the Bc+ production in Pb-Pb collisions at sNN=5.02 TeV. In the quark-gluon plasma (QGP) produced in heavy-ion collisions, heavy quarks make random motions with the energy loss. We employ the Langevin equations to study the non-equilibrium distributions of heavy quarks and the Instantaneous Coalescence Model (ICM) to study the hadronization process. Due to abundant charm and bottom quarks in the QGP, their coalescence probability is significantly enhanced compared with the situations in proton-proton collisions. We find that the final production of Bc+ is increased by the coalescence process, which makes the nuclear modification factor (RAA) of Bc+ larger than unit. Our model explains the experimental data well at semi-central and central collisions. The observation of RAA(Bc+)>1 is regarded as an evident and strong signal of the existence of the deconfined medium generated in heavy-ion collisions.

Enhancing fracture network characterization: A data-driven, outcrop-based analysis

We utilize a pixel-based fracture detection algorithm to digitize 80 published outcrop maps of different scales at different locations. The key fracture properties, including fracture lengths, orientations, intensities, topological structures, clusters, and flow, are analyzed. Our findings provide significant justifications for statistical distributions used in SDFN modelings. We find that fracture lengths follow multiple (instead of single) power-law distributions with varying exponents. Large fractures tend to have large exponents, possibly because of a small coalescence probability. Most small-scale natural fracture networks have scattered orientations, corresponding to a small κ value (κ<3) in a von Mises–Fisher distribution. Large fracture systems analyzed in this research usually have more concentrated orientations with large κ values. Fracture intensities are spatially clustered at all scales. A fractal spatial density distribution, which introduces clustered fracture positions, can better capture the spatial clustering than a uniform distribution. Natural fracture networks usually have a significant proportion of T-type nodes, which is unavailable in conventional SDFN models. Thus, a rule-based algorithm is necessary to mimic the fracture growth and form T-type nodes. Most outcrop maps show good topological connectivity. However, sealing patterns and stress impact must be considered to evaluate the hydraulic conductivity of fracture networks.

Coalescence law of microdroplet swarms in microchannels

Droplet microfluidic technology refers to the technique of preparing and controlling microscale monodisperse droplets by shear force and interfacial tension of two immiscible phases accurately, which has a wide range of applications in biomedicine, chemical reaction enhancement, nanoparticle preparation, and other fields due to its efficient mass and heat transfer, easy manipulation, rapid response, and high throughput. In the application of droplet microfluidic technology, coalescence often occurs due to the structural complexity of microchannels, which limits the practical application performance. The mechanism of droplet coalescence has been widely studied in conventional reactors, among which the liquid film drainage theory is the most widely accepted. To achieve accurate control of the droplet coalescence process, there have been many studies on droplet coalescence in microchannels. A variety of microchannel structures have been proposed and the mechanism and influencing factors of double droplets coalescence have been explored. However, most of the existing studies on coalescence are based on cross structures, mainly studying the coalescence of double droplets in confined systems. There is still a lack of research on the coalescence process of droplet swarms, which is more widespread in practical applications. Therefore, this work used the rectangular expansion structure to realize the droplet coalescence and explored the effects of two-phase flow rate, continuous phase viscosity, surfactant concentration, and the size of expanding channel on the droplet coalescence behavior. The coalescence types, probabilities, and size distributions of microdroplet swarms under different factors were summarized. The time distribution of liquid film drainage in the droplet coalescence process and the influence of various factors on it were further analyzed based on the liquid film drainage theory.

Limiting distribution of X-chromosomal coalescence times under first-cousin consanguineous mating

By providing additional opportunities for coalescence within families, the presence of consanguineous unions in a population reduces coalescence times relative to non-consanguineous populations. First-cousin consanguinity can take one of six forms differing in the configuration of sexes in the pedigree of the male and female cousins who join in a consanguineous union: patrilateral parallel, patrilateral cross, matrilateral parallel, matrilateral cross, bilateral parallel, and bilateral cross. Considering populations with each of the six types of first-cousin consanguinity individually and a population with a mixture of the four unilateral types, we examine coalescent models of consanguinity. We previously computed, for first-cousin consanguinity models, the mean coalescence time for X-chromosomal loci and the limiting distribution of coalescence times for autosomal loci. Here, we use the separation-of-time-scales approach to obtain the limiting distribution of coalescence times for X-chromosomal loci. This limiting distribution has an instantaneous coalescence probability that depends on the probability that a union is consanguineous; lineages that do not coalesce instantaneously coalesce according to an exponential distribution. We study the effects on the coalescence time distribution of the type of first-cousin consanguinity, showing that patrilateral-parallel and patrilateral-cross consanguinity have no effect on X-chromosomal coalescence time distributions and that matrilateral-parallel consanguinity decreases coalescence times to a greater extent than does matrilateral-cross consanguinity.