Dispersal Mechanisms Research Articles

Nanotechnology in the Fabrication of Advanced Paints and Coatings: Dispersion and Stabilization Mechanisms for Enhanced Performance

Nanotechnology in the Fabrication of Advanced Paints and Coatings: Dispersion and Stabilization Mechanisms for Enhanced Performance

New dispersion mechanism for oxide dispersion-strengthened steels by liquid metallurgy

The use of oxide dispersion-strengthened (ODS) alloys in demanding applications can effectively reduce parts’ weights, extend life of use, and enhance overall energy efficiency. But, the current manufacturing of ODS alloys has remained impractical for decades due to poor scalability and extremely high costs. Mass production of ODS steels by liquid metallurgy is therefore crucial to decrease their costs by several orders of magnitude and expand their potential applications. However, oxide nanoparticle (NP) dispersion in molten alloys presents fundamental challenges for liquid metallurgy due to the vastly dissimilar atomic properties between ionocovalent oxides and metals. Here we show, for the first time, that Y2O3 NPs are able to be dispersed in liquid 316L with a 1 % Nb addition. It was discovered that Nb-enriched interfacial layers exist around the Y2O3 NPs in solidified steels after slow cooling. Theoretical analyses reveal that the Nb-enriched interfacial layer induces a higher energy barrier and a significantly lower van der Waals attraction between oxide NPs and liquid Fe for the successful dispersion of oxide NPs in liquid steels. Moreover, Y2O3 and Al2O3 NPs were successfully dispersed in lean steels, such as Fe-Nb and low-C steels. This new dispersion mechanism of oxide NPs opens an exciting pathway for the economical mass manufacturing of various ODS alloys by liquid metallurgy for numerous applications.

Tracing Geographic and Molecular Footprints of Copepod Crustaceans Causing Multifocal Purple Spots Syndrome in the Caribbean Sea Fan Gorgonia ventalina

The recent rise in ocean temperatures, accompanied by other environmental changes, has notably increased the occurrence and spread of diseases in Octocorallia, many species of which are integral to shallow tropical and subtropical coral reef ecosystems. This study focuses on the understanding of these diseases, which has been largely limited to symptomatic descriptions, with clear etiological factors identified in only a fraction of cases. A key example is the multifocal purple spots syndrome (MFPS) affecting the common Caribbean octocoral sea fan Gorgonia ventalina, linked to the gall-forming copepods of the genus Sphaerippe, a member of the widespread family, Lamippidae. The specialized nature of these copepods as endoparasites in octocorals suggests the potential for the discovery of similar diseases across this host spectrum. Our investigation employed four molecular markers to study disease hotspots in Saint Eustatius, Curaçao, northwest and southwest Cuba, and Bonaire. This led to the discovery of a group of copepod species in these varied Caribbean locations. Importantly, these species are morphologically indistinguishable through traditional methods, challenging established taxonomic approaches. The observed diversity of symbionts, despite the host species’ genetic uniformity, is likely due to variations in larval dispersal mechanisms. Our phylogenetic analyses confirmed that the Lamippidae copepods belong to the order, Poecilostomatoida (Copepoda), and revealed their sister group relationship with the Anchimolgidae, Rhynchomolgidae, and Xarifiidae clades, known for their symbiotic relationships with scleractinian corals. These results add to our understanding of the evolutionary and ecological interactions of copepods and their hosts, and the diseases that they cause, and are important data in a changing climate.

Earwigs and woodlice as some of the world's smallest internal seed dispersal agents: Insights from the ecology of Monotropastrum humile (Ericaceae)

Societal Impact StatementThis study illuminates the underappreciated role of invertebrates in seed dispersal, extending beyond the well‐documented contributions of ants. Focusing on Monotropastrum humile (銀竜草 [silver dragon plant] or 水晶蘭 [crystal orchid]), a non‐photosynthetic plant known for its minuscule, dust‐like seeds, the present research uncovers their seed dispersal roles of woodlice and earwigs in Japan. Remarkably, these invertebrates include the smallest known endozoochorous seed dispersers.Summary Endozoochory, or internal seed dispersal through the digestive tracts of animals, has been less studied in invertebrates compared with vertebrates. Nonetheless, endozoochory is plausible whenever seeds are small enough for ingestion by frugivorous animals, suggesting a potential role for invertebrates in seed dispersal, especially for plants with minute seeds. Monotropastrum humile (Ericaceae), characterized by its fleshy fruits and dust‐like seeds, is known to utilize invertebrate agents such as camel crickets and cockroaches for seed dispersal. Here, we investigate this seed dispersal mechanism using time‐lapse photography, feeding experiments, and seed coat anatomy analysis, particularly focusing on interactions among undocumented invertebrate internal seed dispersers. Field observations indicated that in the studied population, M. humile fruits were primarily consumed by camel crickets, woodlice, and earwigs. Their effectiveness as seed dispersers varied, with camel crickets primarily acting as dispersers, whereas earwigs and woodlice were more inclined toward seed predation. Nonetheless, some seeds defecated by earwigs and woodlice remained intact, suggesting that they could also function as dispersal agents. The woodlouse Porcellio scaber is now recognized as the world's smallest internal seed dispersal agent. Combined with earlier discoveries, such as seed dispersal by camel crickets, cockroaches, and ants, and the fact that P. scaber is an exotic species in the study site, M. humile likely depends on a broad spectrum of local invertebrates. The engagement of multiple invertebrate dispersers may enhance seed dispersal across diverse habitats.

Performance and mechanism of organic solid-phase sediment composite plugging agent

The surface pipeline sediments of the Yingmai and Hade oil fields mainly contain substances such as asphalt and paraffin. The formation of sediment can increase the backpressure during pipeline transportation, and in severe cases, it can also lead to pipeline blockage. In order to solve this on-site situation, indoor experiments were conducted in the early stage, and an efficient organic unblocking system LXW was optimized and formulated. Based on this system, this article selects the wire mesh filtration method to evaluate the unblocking performance of LXW and on-site unblocking agents in the study and comparison of three evaluation methods. At the same time, based on the analysis of the chemical composition, microstructure, and melting point of organic sediments, from the perspectives of safety, environmental protection, and economic factors, further compares the performance and universality of the three unblocking systems, optimizes the process parameters of the LXW unblocking system, explores its stability and impact on the demulsification and dehydration of crude oil emulsions, and evaluates its safety performance. The LXW unblocking system has a more efficient unblocking effect and better universality, which can solve the problem of multiple block blockages on site. In addition, compared with existing unblocking agents, it has better economic benefits and is in line with the characteristics of low cost on site. On this basis, the dissolution and dispersion mechanism of the blockage system on sediment was studied through laser scattering system and fluorescence microscope, and its microscopic mechanism was further verified. At the same time, the oil-water interfacial tension under the action of the unblocking system was studied, and it was found that adding the agent can significantly reduce the equilibrium interfacial tension, which is of great significance for increasing production and injection.

Dynamic seismic signatures in a fluid‐saturated porous periodically layered medium considering effects of intrinsic anisotropy

AbstractThe interlayer wave‐induced fluid flow is an important mechanism for seismic attenuation and dispersion, as well as frequency‐dependent anisotropy, in the fluid‐saturated porous layered medium. This mechanism is closely related to the medium physical properties, and thus quantifying this mechanism is of significance for the seismic inversion of medium physical properties. Although numerous models have been proposed to quantify this mechanism, most models do not consider the effects of layer intrinsic anisotropy. To solve this problem, the effective complex‐valued and frequency‐dependent stiffness coefficients are derived for the fluid‐saturated porous medium composed of periodic transversely isotropic layers. Using the derived solutions, we study the effects of layer intrinsic anisotropy on seismic dispersion and attenuation, as well as frequency‐dependent anisotropy. It has been found that different matrix or fluid property contrasts between adjacent layers lead to different effects of intrinsic anisotropy. In addition, the effects of intrinsic anisotropy are also influenced by the fluid distribution when both matrix and fluid properties contrast among adjacent layers exist. In the low‐ and high‐frequency limits of wave‐induced fluid flow, our model reduces to the previous known results, which validates the correctness of our model. Our model can be applied in the seismic inversion of physical properties of reservoirs with intrinsic anisotropy, such as shale and tight sandstone reservoirs. In addition, our model can also be extended to cases with more complex intrinsic anisotropy and, thus, can be applied to complex anisotropic fractured reservoirs in the future.

Fine excipient materials in carrier-based dry powder inhalation formulations: The interplay of particle size and concentration effects

The contributions of fine excipient materials to drug dispersibility from carrier-based dry powder inhalation (DPI) formulations are well recognized, although they are not completely understood. To improve the understanding of these contributions, we investigated the influences of the particle size of the fine excipient materials on characteristics of carrier-based DPI formulations. We studied two particle size grades of silica microspheres, with volume median diameters of 3.31 μm and 8.14 μm, as fine excipient materials. Inhalation formulations, each composed of a lactose carrier material, one of the fine excipient materials (2.5% or 15.0% w/w), and a drug (fluticasone propionate) material (1.5% w/w) were prepared. The physical microstructure, the rheological properties, the aerosolization pattern, and the aerodynamic performance of the formulations were studied. At low concentration, the large silica microspheres had a more beneficial influence on the drug dispersibility than the small silica microspheres. At high concentration, only the small silica microspheres had a beneficial influence on the drug dispersibility. The results reveal influences of fine excipient materials on mixing mechanics. At low concentration, the fine particles improved deaggregation and distribution of the drug particles over the surfaces of the carrier particles. The large silica microspheres were associated with a greater mixing energy and a greater improvement in the drug dispersibility than the small silica microspheres. At high concentration, the large silica microspheres kneaded the drug particles onto the surfaces of the carrier particles and thus impaired the drug dispersibility. As a critical attribute of fine excipient materials in carrier-based dry powder inhalation formulations, the particle size demands robust specification setting.

Fracture toughness of graphene/polymer nanocomposites: Well dispersion, agglomeration and toughening mechanisms

The fracture toughness of nanocomposites may be improved by addition of low content of graphene nanofillers. The improvement is directly related to density of isolated graphene nanofillers dispersed in the nanocomposites. In contrast, for higher content of graphene nanofillers, the fracture toughness improvement may be degraded due to agglomerations. Thus, the main aim of this research is to account for the influence of the agglomeration of graphene nanofillers on the fracture toughness of nanocomposites. In the first step, based on J-integral concept, some relations were presented to estimate the fracture toughness improvement due to toughening mechanisms of nanocomposites reinforced by fully isolated and aligned nanofillers. Subsequently, the influence of agglomerations on the fracture toughness of nanocomposites was considered as a semi-empirical factor. Besides, a modified factor was used to account for the random orientation of the nanofillers. To consider the role of crack pinning toughening mechanism caused by agglomerated nanofillers in the fracture toughness of nanocomposites, another relation was presented. At the end, the experimental data available in literature was applied to validate the proposed comprehensive model. It was observed that the results obtained by the model are in very good agreement with the experimental results.

Controlled Size Characterization Process for In-Situ TiB2 Particles from Al Matrix Composites Using Nanoparticle Size Analysis.

The wide size range and high tendency to agglomerate of in-situ TiB2 particles in reinforced Al matrix composites introduce great difficulties in their size characterization. In order to use a nanoparticle size analyzer (NSA) to obtain the precise size distribution of TiB2 particles, a controlled size characterization process has been explored. First, the extraction and drying processes for TiB2 particles were optimized. In the extraction process, alternated applications of magnetic stirring and normal ultrasound treatments were proven to accelerate the dissolution of the Al matrix in HCl solution. Furthermore, freeze-drying was found to minimize the agglomeration tendency among TiB2 particles, facilitating the acquisition of pure powders. Such powders were quantitatively made into an initial TiB2 suspension. Second, the chemical and physical dispersion technologies involved in initial TiB2 suspension were put into focus. Chemically, adding PEI (M.W. 10000) at a ratio of mPEI/mTiB2 = 1/30 into the initial suspension can greatly improve the degree of TiB2 dispersion. Physically, the optimum duration for high-energy ultrasound application to achieve TiB2 dispersion was 10 min. Overall, the corresponding underlying dispersion mechanisms were discussed in detail. With the combination of these chemical and physical dispersion specifications for TiB2 suspension, the bimodal size distribution of TiB2 was able to be characterized by NSA for the first time, and its number-average diameter was 111 ± 6 nm, which was reduced by 59.8% over the initial suspension. Indeed, the small-sized and large-sized peaks of the TiB2 particles characterized by NSA mostly match the results obtained from transmission electron microscopy and scanning electron microscopy, respectively.

Simulating squirt flow in realistic rock models using graphical processing units (GPUs)

SUMMARY Understanding the underlying mechanisms of seismic attenuation and moduli dispersion in fluid-saturated cracked porous rocks is of great importance for the development of non-invasive methods to characterize the subsurface. Wave-induced fluid flow at the pore scale, so-called squirt flow, is responsible for seismic attenuation and moduli dispersion at sonic and ultra-sonic frequencies and may be relevant at seismic frequencies. The squirt flow associated attenuation is usually quantified using analytical models. However, numerical experiments suggest that the squirt flow related dissipation is sensitive to fine details of the pore geometry, which can only be modelled numerically. Most of the existing numerical studies explore this phenomenon using simplified models, and there is a lack of numerical studies that model the physics in realistic pore geometries with sufficient numerical resolution. As a result, the impact of wave-induced fluid flow on the effective static and time-dependent mechanical characteristics in realistic settings is still poorly understood. I address these issues by developing a numerical method to model the effective mechanical properties of a hydromechanically coupled system at the pore scale suitable for graphical processing units. A numerical evaluation of attenuation and modulus dispersion due to squirt flow in models based on 3-D microtomography images of cracked Carrara marble is presented. It is shown that the local hydraulic conductivity can be quantitatively estimated from the numerically evaluated effective properties. The accuracy of the numerical results is carefully analysed. This study improves the understanding of the underlying mechanisms of attenuation and moduli dispersion in fluid-saturated cracked rocks. The new method can be applied to model squirt flow for entire laboratory samples in the centimetre scale which was not possible a decade ago.

Adsorption mechanism of the novel amphoteric dispersant and its effect on structure and properties of hydration products

The novel amphoteric dispersant (NAD) was prepared by free radical polymerization of acrylic acid (AA), vinyl butylpolyoxyethylene ether (VBPE), N,N-dimethyl-methacryloxyethyl-aminopropyl sulfonate (DMAPS) and acrylate sulfated starch (ASS). It is characterized that the introduction of zwitterionic monomer as side groups and modified starch as branch chains. The chemical structure and its effects on the fluidity, strength, durability and microstructure of cement-based composites containing clay were tested. The results indiacted that zwitterions can improve the chelating adsorption capacity and eliminate the influence of chloride ions, while modified starch branch chain can improve the effect of slow coagulation and water retention. NAD has excellent dispersing and mud resistance effect, which makes the interface of cement hydration products clear, regular shape, uniform distribution and compact structure.The dispersion mechanism was proposed and it is think that NAD was mainly adsorbed on the interface of cement particles by zwitterion chelation adsorption and on the interface of the mud particles by anion groups. Meanwhile, the polyoxyethylene and the starch branch chains synergistic to form spatial barrier layer, showing excellent effects on blocking mud water absorption, improving dispersing and regulating hydration products structure. The research results have positive significance for the developing highly effective anti-mud dispersants.

Effective dispersal patterns in prairie plant species across human-modified landscapes.

Effective dispersal among plant populations is dependent on vector behaviour, landscape features and availability of adequate habitats. To capture landscape feature effects on dispersal, studies must be conducted at scales reflecting single-generation dispersal events (mesoscale). Many studies are conducted at large scales where genetic differentiation is due to dispersal occurring over multiple generations, making it difficult to interpret the effects of specific landscape features on vector behaviour. Genetic structure at the mesoscale may be determined by ecological and evolutionary processes, such as the consequences of vector behaviour on patterns of gene flow. We used chloroplast haplotypes and nuclear genome SNP surveys to identify landscape features influencing seed and pollen dispersal at a mesoscale within the Rogue River Valley in southern Oregon. We evaluated biotic and abiotic vector behaviour by contrasting two annual species with differing dispersal mechanisms; Achyrachaena mollis (Asteraceae) is a self-pollinating and anemochoric species, and Plectritis congesta (Caprifoliaceae) is biotically pollinated with barochoric seeds. Using landscape genetics methods, we identified features of the study region that conduct or restrict dispersal. We found chloroplast haplotypes were indicative of historic patterns of gene flow prior to human modification of landscapes. Seed dispersal of A. mollis was best supported by models of isolation by distance, while seed-driven gene flow of P. congesta was determined by the distribution of preserved natural spaces and quality habitat. Nuclear genetic structure was driven by both pollen and seed dispersal, and both species responded to contemporary landscape changes, such as urban and agricultural conversion, and habitat availability.

Strengthening effect of monolayer graphene oxide on the impact mechanical properties of concrete and the mechanism analysis based on fractal theory

Graphene oxide (GO), a new nanomaterial with excellent properties, having the prospect of improving the performance of cementitious composites. Graphene oxide reinforced concrete (GORC) was prepared and the impact tests were performed through a φ100 mm SHPB test apparatus, to investigate the effects of impact velocity and GO content on the impact mechanical properties of concrete. The effects of GO on the pore structure and microscopic morphology of concrete were analyzed by MIP and SEM tests. Furthermore, the pore structure fractal dimension and fragment fractal dimension were calculated to quantitatively relate the microscopic pore structure to the macroscopic impact mechanical properties, and the enhancement mechanism of GO was investigated from microstructure optimization and stress dispersion mechanism. The results show that GO promotes the growth and aggregation of cement hydration products, and significantly improves the quasi-static and impact mechanical properties of concrete through filling-compacting effect and anticracking-unloading effect. When the GO content is 0.06 wt %, GO shows the best improvement effect. Compared with plain concrete (PC), the quasi-static compressive strength, dynamic compressive strength, elastic modulus, DIF, peak strain, ultimate strain and impact toughness are increased by a maximum of 29.95 %, 52.27 %, 9.79 %, 75 %, 51.54 %, 59.6 % and 86.2 % respectively. GORC has an obvious strain rate effect in the impact velocity range of 5.5 m/s-9.5 m/s, and the average particle size of specimen fragments satisfies a logarithmic relationship with the impact velocity. In addition, the pore structure fractal dimension and fragment fractal dimension satisfy a positive correlation. Larger pore structure fractal dimension indicates more defects in concrete and worse mechanical properties of it.

Vicariance and cryptic diversity revealed by molecular phylogenetic analyses of estuarine Gammarus species (Crustacea: Amphipoda) due to formation of the Labrador Current

The metapopulation of the estuarine species Gammarus tigrinus along the east coast of the United States has been hypothesised to represent two cryptic species divided biogeographically off the coast of North Carolina, USA. This divergence has been attributed to a strong temperature gradient created by the formation of the cold Labrador Current c. 3.0 million years ago. In addition, the northern phylogeographic clade of G. tigrinus has been demonstrated to be invasive in estuarine habitats across a large portion of northern Europe. Recent collections of G. tigrinus from Florida and Maryland, USA, allow for new approaches to test this hypothesis. Using the nuclear 18S and 28S rRNA, and mitochondrial 16S rRNA and cytochrome c oxidase subunit I genes, species delimitation models provide support that the genetic divergence of the northern and southern clades is equivalent to species level. In addition, molecular clock data demonstrate that this phylogeographic divergence coincides with the formation of the Labrador Current. Furthermore, the collections of G. daiberi from Florida, a species with biogeographical and ecological characteristics similar to those of G. tigrinus, provide independent support for the hypothesis. The potential for invasive species to be cryptic highlights the need for accurate identification of taxa to ensure that appropriate biogeographical assessment of potential source populations and mechanisms of dispersal can be made.

Modeling of Chemical Tracers for Two-Phase Flow in Advective-Dominated Porous Media at Core Scale

Summary Chemical tracer modeling in porous media plays a key role in subsurface applications including oil recovery, aquifer remediation, and geothermal energy production. In oil reservoirs, chemical tracers are critical to quantifying the remaining oil saturation in porous media after displacing processes, enabling the correct evaluation of the sweep efficiency of recovery methods at the field scale. Even though the transport of solutes under single-phase flow has been modeled extensively with numerous solutions, there are no existing mathematical approaches to examine the displacement of solutes in two-phase flow conditions. Therefore, we present in this research work the first analytical solutions derived to model the transport of ideal and partitioning tracers in porous media with mobile water and oil phases. The models presented are derived from the classic study of fluid displacement by viscous forces and the analysis of dynamic phase distribution in porous media, where key transformation variables are introduced to simplify the nonlinear advection-dispersion equation (ADE) into a conventional partial differential expression. In our derivation process, it is recognized that the dispersion effect can be superimposed onto an ideal concentration front via a singular perturbation expansion, resulting in practical solutions that do not require complex numerical calculations or inversion methods. The solutions derived are verified with numerical simulations and validated with experimental data under different flow conditions for the transport of ideal and partitioning tracers, demonstrating that the complex mechanisms of hydrodynamic dispersion, partitioning, and adsorption are accurately modeled under two-phase flow. Thus, our solutions can be used to rapidly evaluate tracer transport under the existing flow conditions in porous media, significantly reducing the number of experiments and simulations to characterize and select the correct tracer to be used in field applications.

An Unprecedented Metal Distribution in Silica Nanoparticles Determined by Single-Particle Inductively Coupled Plasma Mass Spectrometry.

Metal-containing nanoparticles are now common in applications ranging from catalysts to biomarkers. However, little research has focused on per-particle metal content in multicomponent nanoparticles. In this work, we used single-particle inductively coupled plasma mass spectrometry (ICP-MS) to determine the per-particle metal content of silica nanoparticles doped with tris(2,2'-bipyridyl)ruthenium(II). Monodispersed silica nanoparticles with varied Ru doping levels were prepared using a water-in-oil microemulsion method. These nanoparticles were characterized using common bulk-sample methods such as absorbance spectroscopy and conventional ICP-MS, and also with single-particle ICP-MS. The results showed that averaged concentrations of metal dopant measured per-particle by single-particle ICP-MS were consistent with the bulk-sample methods over a wide range of dopant levels. However, the per-particle amount of metal varied greatly and did not adhere to the usual Gaussian distribution encountered with one-component nanoparticles, such as gold or silver. Instead, the amount of metal dopant per silica particle showed an unexpected geometric distribution regardless of the prepared doping levels. The results indicate that an unusual metal dispersal mechanism is taking place during the microemulsion synthesis, and they challenge a common assumption that doped silica nanoparticles have the same metal content as the average measured by bulk-sample methods.

Style head in Apocynaceae: a very complex secretory activity performed by one tissue.

Nuptial glands are very diverse and associated with different pollination mechanisms. The greater the specificity in the pollen transfer mechanism from anther to stigma, the greater the morphological elaboration of flowers and functional complexity of the nuptial glands. In Apocynaceae, pollination mechanisms reached an extreme specificity, a fact that was only possible due to an extreme morphological synorganization and a profusion of floral glands. Although these glands are of different types, the vast majority have secretory cells only in the epidermis. In general, these epidermal cells produce many different compounds at the same time, and previous studies have demonstrated that in the style head, the functional complexity of epidermis has become even greater. Four types of style head are found in the family, which have different degrees of functional complexity in relation to the secretion produced and pollen dispersal mechanism. The secretion is fluid in types I, II and III, and the pollen is dispersed and adhered to the pollinator by the secretion produced by the style head. In type IV, the secretion hardens and acquires a specific shape, moulded by the spatial constraints of the adjacent floral organs. This evolutionary alteration is accompanied by changes in the structure and arrangement of the secretory cells, as well as in pollen aggregation and position of stigma. Histochemical analysis has shown that the secretion is mixed and highly complex, especially in the style head type IV, where the secretion, called translator, is formed by a rigid central portion, which adheres to the pollinator, and two caudicles that attach to two pollinia. The translator has a distinct composition in its different parts. Further studies are needed to answer the new questions that have arisen from the discovery of this highly functional complexity of the secretory tissue.

Role of Rain in the Spore Dispersal of Fungal Pathogens Associated with Grapevine Trunk Diseases.

Grapevine trunk diseases are caused by a complex of fungi that belong to different taxa, which produce different spore types and have different spore dispersal mechanisms. It is commonly accepted that rainfall plays a key role in spore dispersal, but there is conflicting information in the literature on the relationship between rain and spore trapping in aerobiology studies. We conducted a systematic literature review, extracted quantitative data from published papers, and used the pooled data for Bayesian analysis of the effect of rain on spore trapping. We selected 17 papers covering 95 studies and 8,778 trapping periods, concerning a total of 26 fungal taxa causing Botryosphaeria dieback (BD), Esca complex (EC), and Eutypa dieback (ED). Results confirmed the role of rain in the spore dispersal of these fungi but revealed differences among the different fungi. Rain was a good predictor of spore trapping for ED (AUROC = 0.820) and BD (0.766) but not for the ascomycetes involved in EC (0.569) and not for the only basidiomycetes, Fomitiporella viticola, studied as for spore discharge (AUROC not significant). Prediction of spore trapping was more accurate for negative prognosis than for positive prognosis; a rain cutoff of ≥0.2 mm provided an overall accuracy of ≥0.61 for correct prognoses. Spores trapped in rainless periods accounted for only <10% of the total spores. Our analysis had some drawbacks, which were mainly caused by knowledge gaps and limited data availability; these drawbacks are discussed to facilitate further research.

Bird‐mediated endozoochory as a potential dispersal mechanism of bony fishes

The dispersal of fish into distant and isolated habitats remains a topic of continuous discussion in the field of fish biogeography. This is particularly relevant due to the perceived limitation of fish movement to what is known as active dispersal. Fish migration is often confined to interconnected water bodies, underscoring the significance of dispersal for fish inhabiting isolated aquatic habitats. However, empirical evidence for a natural (i.e. not human‐mediated) mechanism has been limited. Here we explore and provide evidence for waterbird‐mediated endozoochory as a possible dispersal mechanism in various fish species and families. We force‐fed mallards Anas plathyrynchos with fertilised eggs of nine bony fish species, covering nine taxonomic families. We recovered viable embryos of five fish taxa in the faeces of mallard, proving the ability of fish eggs to survive the passing of the digestive system of waterbirds. Moreover, the recovered eggs successfully hatched into larvae in two fish species. Taking into the flight speed and numerosity of mallards, as well as the high abundance of fish eggs, our results highlight endozoochory of fish eggs by waterbirds as a possible significant, although likely rare natural dispersal mechanism that can occur across more species than previously known in freshwater fish.

Liquid dispersion behaviors in a rotating packed bed with different packing arrangements: A comparison study

Wire mesh packing is widely used in the rotating packed bed (RPB). Packing arrangements have been proven to influence the mass transfer of an RPB. However, the liquid dispersion behaviors including dispersion characteristics and mechanisms for packing with different arrangements require further study. In this work, the dispersion behaviors of wire mesh packing with coiled and concentric arrangements were compared. An in-situ Doppler optical probe method was firstly employed to obtain fundamental parameters of liquid dispersion characteristics, such as the Sauter mean diameter, size distribution, and velocity of liquid droplets. The obtained results showed that the coiled arrangement was conducive to generating droplets with large velocity and narrow size distribution owing to the capturing and spreading of liquid inside the packing, while the concentric arrangement was beneficial in decreasing droplet size due to the shearing and carrying actions of the packing. Based on the optimization of liquid dispersion, the max and average reductions of d32 were 34.8% and 19.0% for packing with concentric arrangement than a coiled one. Further comparison results of dispersion characteristics indicated that the optimized concentric arrangement with 3 layers could provide better liquid dispersion than that of a coiled one with around 20 layers.