Droplet Distribution Research Articles

Influence of tea leaf morphology on water interception for droplet impact

AbstractIt is common for plant canopy to intercept water during rainfall or sprinkler irrigation. How tea leaves intercept water droplets are unknown. The objective of this study is to investigate the influence of different shapes of tea leaves on the water droplet retention and distribution. First, the shapes of different tea varieties (Zhongcha 108, Maolu, Longjing 43, Huangjinya, and Anji Baicha) were statistically classified, and a high‐speed camera (with a frame rate of 10 000 fps) was used to record and analyse the interception of single droplet. The results showed that the morphology of tea leaves is flat, V‐shaped and hemispherical. The percentage of flat shaped leaves is the highest in each variety (45.38%–63.20%), the proportion of V‐shaped leaves is 30.40%–42.97%, and the proportion of hemispherical leaves is the least. When the impact velocity is 1.35 ± 0.05 m/s, it takes only 20–26 ms for droplet to start hitting each morphology of leaves and be retained as a static liquid. Droplets were kept as a film of water on the flat leaf, and similar situation happened to the hemispherical leaf, but they slid downward due to gravity. When impact position is near the midrib or leaf surface angle is smaller, retained droplets tends to converge to the bottom of the V‐shape with a symmetrical distribution. This study aids to better understand and model water interception within tea canopies for future practice of irrigation and chemical spraying.

In-flight imaging of aerosol jet printer droplets to enable spatially resolved flow rate measurements

The effect of process drift in aerosol jet (AJ) printing has been a hindering factor in its large-scale adoption in printed electronics. In this study, we developed an in situ droplet imaging system using a double-pulse laser to quantify the distribution and velocity of sparse droplets between the AJ printer nozzle and the substrate. The droplet velocity and distribution were then used to evaluate a spatially resolved droplet flow rate that was capable of detecting and quantifying process drift over time. Using the droplet imaging system, the effect of different focus ratios was analyzed. The droplet flow rate was shown to be indicative of the deposited line morphology for low to moderate focus ratios. At a high focus ratio, the tool was able to identify non-idealities in the fluid properties which are explained in a detailed analysis. AJ printing demonstrates significant promise for the additive manufacturing of electronics, and this work represents a step toward non-invasive, in-flight monitoring in real time.

Nanoparticle-Assisted Liquid Crystal Droplet Sensors Enable Analysis of Low-Concentration Species in Aqueous Medium.

We introduce nanoparticle-assisted liquid crystal (LC) droplet-based sensors that allow determination of low-level concentrations of aqueous soluble species. The silica nanoparticles functionalized with mixed monolayers composed of two distinct groups, hydrophobic alkane tail- and charged group-terminated silanes, facilitated ternary physical interactions between the model analytes (methylene blue (MB) or methyl orange (MO)) and the nematic mesogens 5CB (4-cyano-4'-pentylbiphenyl), and the interfacial species of the nanoparticle. The response of the LC droplets was measured upon nanoparticle adsorption as a function of analyte concentration, which was characterized by the optical determination of the configuration distributions of the LC droplets. We highlight the importance of the charging and the composition of the nanoparticle interfaces for analytical purposes that allow accurate determination of the concentration of the analytes on the order of 0.01 ppb. Such a low concentration corresponds to a low interfacial coverage of nanoparticles, indicating the promisingly high sensitivity of the sensor platform to target analytes. Distinct from the past examples of the LC-based sensors, the nanoparticle-assisted LC sensors allow detection of the species that do not directly cause an ordering transition at the LC-water interfaces, which allow a broader range of analytical targets. The sensor platform that we report herein can be easily tunable for a range of target molecules and will find use in the determination of a wide range of micropollutants in aqueous environments.

Critical Review of Techniques for Food Emulsion Characterization

Emulsions have garnered significant attention within a variety of industries, including pharmaceuticals, food production, and cosmetics. The importance of emulsions across these sectors is attributed to their versatility and unique properties, such as increased interfacial area and the ability to deliver compounds insoluble in water or to mask the flavor of unpalatable ingredients. A comprehensive and precise assessment of the physicochemical properties, structural features, and stability of emulsions is an indispensable phase in the pursuit of new formulations and the improvement of manufacturing protocols. The characterization of emulsions encompasses an array of methodologies designed to determine their attributes, such as droplet size, distribution, concentration, surface charge, and others. In this review, we explore the techniques most frequently used to characterize emulsions and critically assess the significance each method holds in understanding the behavior and predicting the stability of emulsions. We elucidate the basic principles of these methods while emphasizing what information can be gathered from them, and how to effectively interpret this information to optimize the properties of emulsions, crucial from the standpoints of food and other industries, such as long-term stability and easy processing.

Picosecond laser drilling grids in aluminium foil at 532 and 355 nm wavelengths

Ultra-short laser drilling technique enables production of filters, membranes, microfluidic, photonic, and biomedical devices. Micro-hole grids were drilled in aluminum foil using a 28 picosecond Nd:YAG laser operated at wavelength of 532 and 355 nm with energy up to 18 and 12 mJ, respectively. Varying pulse energy and number, micro-holes obtained at 355 nm and 3.6–9 mJ had the appropriate mean diameter of 36–86 μm. However, the circularity changed in 0.5–0.94. For the 2nd harmonic the mean diameter varied 15–61 μm at 0.36–9 mJ with the circularity of 0.81–0.92. The morphology of the area surrounding micro-holes investigated by scanning electron microscopy exhibited distribution of droplets dominated size 0.9–10 μm, which is feasible for filtration of contaminated liquids. Local elemental composition of the area determined by energy dispersive spectroscopy discovered significant increase in the concentration of C and O, and also emergency of F, depending on laser fluence under vapor-dominated ablation mode, where nuclear reactions are excited in hot plasma.

Extracellular lipidosomes containing lipid droplets and mitochondria are released during melanoma cell division

BackgroundThe incidence of melanoma is increasing worldwide. Since metastatic melanoma is highly aggressive, it is important to decipher all the biological aspects of melanoma cells. In this context, we have previously shown that metastatic FEMX-I melanoma cells release small (< 150 nm) extracellular vesicles (EVs) known as exosomes and ectosomes containing the stem (and cancer stem) cell antigenic marker CD133. EVs play an important role in intercellular communication, which could have a micro-environmental impact on surrounding tissues.ResultsWe report here a new type of large CD133+ EVs released by FEMX-I cells. Their sizes range from 2 to 6 µm and they contain lipid droplets and mitochondria. Real-time video microscopy revealed that these EVs originate from the lipid droplet-enriched cell extremities that did not completely retract during the cell division process. Once released, they can be taken up by other cells. Silencing CD133 significantly affected the cellular distribution of lipid droplets, with a re-localization around the nuclear compartment. As a result, the formation of large EVs containing lipid droplets was severely compromised.ConclusionGiven the biochemical effect of lipid droplets and mitochondria and/or their complexes on cell metabolism, the release and uptake of these new large CD133+ EVs from dividing aggressive melanoma cells can influence both donor and recipient cells, and therefore impact melanoma growth and dissemination.

Effect of different forms of nanocellulose on the stability of pork myofibrillar proteins' emulsion system

SummaryMyofibrillar proteins (MP) and two forms of nanocellulose (cellulose nanofibers [CNFs] and cellulose nanocrystals [CNCs]) were used to prepare oil‐in‐water emulsion. The effect of CNFs and CNCs on the properties of pork MP‐lard emulsion was studied by analysing the emulsion index, microstructure, oil droplet size, zeta potential and rheological behaviour of emulsion. The results showed that both CNFs and CNCs improved MP‐lard emulsion stability. At the same nanofiber concentration, the creaming index of CNFs stabilised emulsion was lower than that of CNCs stabilised emulsion, especially at the concentration of 0.5%, emulsion prepared with CNFs has no phenomenon of creaming index, while emulsion prepared with CNCs still has creaming index phenomenon. At the same nanofiber concentration, the oil droplet distribution of CNFs stabilised emulsion was more uniform, especially at low concentrations (≤0.5%). At higher cellulose concentration (≥0.75%), the particle size of CNFs stabilised emulsion was larger than that of CNCs stabilised emulsion. CNFs stabilised emulsion had a higher zeta potential and modulus than that of CNCs stabilised emulsion and the emulsion formed by CNFs was more viscoelastic.

STK11 (LKB1) mutation suppresses ferroptosis in lung adenocarcinoma by facilitating monounsaturated fatty acid synthesis.

Serine/threonine kinase 11 (STK11), a tumor suppressor gene, exhibits frequent mutations in lung adenocarcinoma (LUAD). However, the specific molecular mechanisms by which STK11 mutations exert an influence on the biosynthesis of monounsaturated fatty acids (MUFAs) and subsequently affect ferroptosis in LUAD remain indistinct. In this study, bioinformatic analysis was employed to probe into the linkage between STK11 and key inhibitory genes of ferroptosis, namely SLC7A11 and SCD1, in LUAD tissues. Quantitative reverse transcription polymerase chain reaction was employed to assess the expression of STK11 in both wild-type and mutant STK11 LUAD cells, cell counting kit-8 to assess cell viability, and flow cytometry to detect apoptosis. A transmission electron microscope was utilized to observe mitochondrial morphology, and Western blot to ascertain the protein expression of STK11, ferroptosis-related proteins, and the enzyme SCD1 involved in MUFA synthesis. Oil red O staining was employed to test the distribution of lipid droplets in cancer cells, and a lipid quantification method to measure the content of MUFAs. Commercial kits were employed to assess the levels of lipid reactive oxygen species, malondialdehyde, glutathione, and Fe2+ in cells. The result revealed a negative correlation between STK11 and SLC7A11 as well as SCD1, with STK11 expression downregulated in mutant STK11 LUAD cells. Furthermore, STK11 mutations were found to suppress ferroptosis in LUAD cells by affecting MUFA synthesis. Subsequent rescue assays demonstrated that STK11 mutations hindered ferroptosis by impacting the synthesis of MUFAs in LUAD cells. This study provided evidence that STK11 mutations suppressed ferroptosis in LUAD cells by promoting MUFA synthesis, thus offering a novel research direction in the management of LUAD.

Spray characteristics of a self-aspirating ethanol ejector for high-efficiency combustion-based thermoelectric micropower generators

Low energy conversion efficiencies of combustion-based micropower generators due to parasitic losses continue to be a persistent challenge that limits their practical applications. This work puts forward a new strategy of liquid fuel delivery to a microcombustor with improved atomization and minimum parasitic energy losses. In the present work, a self-aspirating spray ejector is developed, providing continuous ethanol fuel delivery in the form of micron-sized droplets to a microcombustor of ∼ 1.0 kW thermal input capacity. The ejector base- setup works on the principle of generating a low-pressure zone through gas expansion, leading to the self-aspiration of ethanol fuel. The emerging annular ethanol film manifests a shear instability at the liquid–gas interface and subsequently breaks up into ligaments and fine micron-sized droplets. It was observed that the hydrostatic pressure of gas and aerodynamic Weber number (We) significantly affect the ethanol ejection rate, Sauter mean diameter (SMD), droplet distribution, and entrainment ratio of the spray ejector. The spray characteristics, such as mean droplet velocity and spray angle, are mainly governed by a single parameter, i.e., aerodynamic Weber number (We). The maximum power consumption for the spray ejector during the steady-state operation is ∼ 0.1 % of thermal input. The present investigation suggests that the self-aspirating spray ejector generates a fine and fully developed spray with ultra-low energy input requirement and, thus, can be a potential candidate for the development of high-efficiency combustion-based thermoelectric micropower generators.

The Primary Breakup and Atomization Characteristics of Liquid Jet in Crossflow at the Fixed Momentum Ratio and Weber Number

ABSTRACT The primary breakup behaviors of injected fuel were investigated by high fidelity simulation. The influence of various parameters on the breakup and atomization was analyzed at the fixed momentum ratio and Weber number. The results indicated that a simultaneous increase of the surface tension coefficient and the velocity of crossflow will hardly affect axial waves. The air density primarily affected the friction acting on the liquid column near the nozzle, while the liquid density affected the liquid flow in the liquid column to the sides. These variations lead to differences in breakup modes. The evolution of liquid column shape at different penetration heights suggested that the formation of sheet-like structures on the sides of liquid column was one of the main reasons for its deflection. The deflection of liquid column was enhanced by the increase of air density, and it was weakened at the increase of surface tension coefficient. In addition, it was also observed that for different parameters, the change of the boundary of spray plume in the y direction corresponded to variations in liquid column deflection. The diameter distribution of droplets generated by the primary breakup was predominantly influenced by density, with only a slight impact from the surface tension coefficient.

Analysis of the droplet size and distribution for micro-sprinkling hose based on the LPM

Analysis of the droplet size and distribution for micro-sprinkling hose based on the LPM

Microvesicle-Embedded Solid-liquid Composite Coating for the Tribological Behavior Regulation and Long-Acting Lubrication.

Friction interfaces in liquid-embedded composite lubrication coatings commonly comprise a combination of discontinuous fluid films and rough solid contact surfaces, which together ensure easy shearing and a prolonged wear life. However, achieving high efficacy in mixed lubrication poses a challenge due to the conflicting nature of enhanced migration freedom for the liquid lubricant and increased mechanical strength of the solid matrix. Recent efforts have focused on incorporating reinforcing fillers to develop multicomponent, multiphase composites that can address this paradox. Here, we describe a modified attapulgite (APT) with strong biphasic wettability via the oil decompressive osmosis treatment on APT nanocontainers grafted with long nonpolar alkyl chains. This modified APT enables control over the size, distribution, and mobility of lubricant droplets by constructing a Pickering emulsion and toughens the solid-phase matrix through dispersion strengthening. Additionally, the introduction of APT induces the formation of a solid tribofilm during friction, which possesses a higher oil adsorption capacity, as verified through first-principles calculations based on density functional theory (DFT). Consequently, the fluid films can be replenished by the fracture of nanocontainers and adsorption from the bulk phase; further comprehensive and effective regulation of the friction interface leads to low friction and wear.

Моделирование тушения пожаров полигонов твёрдых коммунальных отходов водной средой в метастабильном фазовом состоянии

Purpose. Physical-chemical processes occurring during fires within municipal solid waste (MSW) landfills have been studied quite thoroughly by now. Previous studies have established that water streams in metastable phase state are the most effective means for extinguishing these fires. However, droplets diameter of aqueous medium in metastable phase state at which the extinguishing time of these fires will be minimal, has not been defined theoretically or experimentally. The aim of the work is to establish the dependence of MSW landfills extinguishing time on droplets diameter of aqueous medium in metastable phase state (AMMPhS). The authors' objectives have been the existing models analysis, developing a model for extinguishing MSW landfills with aqueous medium in metastable phase state in the PyroSim hardware and software system, and mathematical modeling of MSW landfills flooding process with aqueous medium in metastable phase state. Methods. Analysis and synthesis methods have been used to assess the available data. The theory of branched-chain combustion processes has been used to study flooding processes. Findings. The study has allowed creating a model for extinguishing MSW landfills with aqueous medium in metastable phase state. The dependences of extinguishing time, humidity in local extinguishing volume on AMMPhS droplets diameter have been established. Research application field. The obtained models can be used to improve fire extinguishing efficiency at MSW landfills. The results of the study will also allow forming theoretical basis for describing the dependence of the extinguishing time of fires at MSW landfills on AMMPhS droplets diameter. Conclusions. Based on the results of the conducted modeling of municipal solid waste landfill fire extinguishing via water systems with different droplet distributions in the extinguishing medium volume, it has been found that decrease in the municipal solid waste landfill extinguishing time is observed with increase in the droplet diameter from 10 to 50 μm. For effective suppression of municipal solid waste combustion at landfills using AMMPhS it is advisable to use a barrel with a nozzle in the form of a washer with a sharp edge, which allows for the production of droplets with a diameter of 50 μm.

Acoustic modulation and non-contact atomization of droplets based on the Fabry-Pérot resonator.

A non-contact ultrasonic atomization based on the Fabry-Pérot resonator is proposed to obtain atomized droplets with a reduced droplet diameter and concentrated droplet distributions. To better understand the mechanism inside the acoustic chamber, the acoustic-fluid interactions are numerically explored inside the Fabry-Pérot resonator to achieve the precise modulation of droplets. The influence of the acoustic chamber's geometry and the ultrasonic properties on the atomized droplet diameter and distributions is investigated, aiming to establish matching relationships between the atomized droplet diameter and the geometry of the acoustic chamber. The dynamic behaviors of droplet breakup are observed with a high-speed camera to reveal the atomization mechanism of liquid droplets in high-intensity acoustic fields. The experiments demonstrate that the proposed non-contact atomization can achieve atomized water droplets with a median diameter of ∼24 μm, providing an alternative to ultrasonic spray.

Numerical Modelling of Water Mist Dispersion Due to Traffic

In winter, de-icing salt causes degradation of traffic structures in the vicinity of the road. The article deals with the numerical analysis in Ansys Fluent software of the transport of water mist from passing cars in order to solve the microclimatic situation around the road. As part of the numerical analysis, a domain was created based on a specific road cut, where measurements of deposition chloride ions will be taking place. The content of the article was an evaluation of the distribution and quantity of salt fog droplets injected from the tires of a passing vehicle falling into the near and far surroundings of the road. Four wind direction variants were evaluated, two from the front and two from the back, all with the wind entering at 60-degree angle. Droplets on three sampling zones at distances of 5, 9 and 13 m from the vehicle axis were monitored. A strong influence of the wind on the behavior of the swirling particles behind the vehicle was confirmed.

Effect of Inulin on Rheological Properties and Emulsion Stability of a Reduced-Fat Salad Dressing.

This study is aimed at investigating the potential use of inulin in a reduced-fat salad dressing to improve its rheological properties, fat globule size distribution, and emulsion stability. The reduced-fat salad dressing, which has 50% less fat compared to the full-fat counterpart (control), was prepared with varying inulin concentrations (10, 12.5, 15, 17.5, and 20% w/w). The full-fat and reduced-fat salad dressings exhibited a non-Newtonian shear-thinning behavior. Power law model was used to describe the rheological properties. Results showed that the flow behavior index (n) and consistency coefficient (K) were greatly affected by the concentration of inulin. A greater pseudoplasticity and apparent viscosity of the reduced-fat samples were achieved with a higher concentration of inulin. Oscillatory tests showed that the storage modulus (G') and loss modulus (G ″) values increased with increasing inulin concentration. All samples displayed characteristics of a viscoelastic solid, as evidenced by a greater G' than G ″. Regarding the size distribution of the oil droplets, the reduced-fat salad dressing containing a higher inulin content was observed to have a larger droplet size. All reduced-fat samples, similar to the full-fat counterparts, exhibited stability with no cream separation over one month of storage at 4°C, as determined by visual observation. Additionally, the reduced-fat salad dressings supplemented with 17.5 and 20% inulin exhibited stability against cream separation, comparable to the full-fat counterpart (p > 0.05), as measured by the thermal stress test (80°C for 30 min) with centrifugation. The sensory acceptance scores for reduced-fat salad dressing with 15 and 17.5% inulin, ranging from approximately 6.28 to 7.63 on a 9-point hedonic scale for all evaluated attributes (appearance, color, aroma, texture, taste, and overall acceptability), were not significantly different from those of the full-fat counterpart (p > 0.05). This study demonstrated that inulin may be a suitable ingredient in reduced-fat salad dressings.

A Respiratory Simulator for the Study of Pathogen Transmission in Indoor Environments

Detailed investigation of pathogen transmission by respiratory droplets requires extensive experimental datasets with high spatial–temporal resolution in a wide range of ambient conditions. Respiratory simulators are attractive tools for those measurements, because they improve repeatability, endurance, and control of experimental conditions with respect to studies on human subjects. They also enable the use of powerful experimental techniques, which may raise health concerns if employed on humans. In this paper, we design and present a respiratory simulator, which is capable of accurately reproducing physiological flow rate profiles and allows the investigation of the spatial and temporal features of the exhaust flow by background‐oriented schlieren (BOS) and particle image velocimetry (PIV). We use laser interferometry and high‐magnification shadowgraphy to verify the size distributions of the emitted droplets, and we quantify the evolution of the droplet concentration during cough events by Mie scattering analysis. The experiments demonstrate the ability of the respiratory simulator to generate highly reproducible cough events with precise and controllable droplet size distributions over a wide range of flow rates.

ДИСПЕРСНЫЙ СОСТАВ ЖИДКОЙ ФАЗЫ ВИХРЕВОГО СЕПАРАЦИОННОГО УСТРОЙСТВА

The vortex form of multiphase flows is often organized in installations used in the electric power industry, petroleum, chemical, and nuclear energy. Separators of various designs are used to separate gas-liquid flows. Prediction of the composition of the dispersed phase is essential for the proper design, operation, and optimization of two-phase flow systems, since such a parameter as the efficiency of the separator strongly depends on the operating mode and the nature of droplet breakup. The dynamics of the gas-liquid flow under swirling conditions is of great interest, has been studied, and has several mathematical models of droplet breakup. The analysis of the factors influencing the separation characteristics of the device depending on the characteristic zones of the droplet layer is carried out. On this basis, an experimental setup determined the size distribution of liquid droplets at the inlet to the vortex separation device with a change in the average velocity of the gas through the device from 15 to 23 m/s and a liquid phase rate of 150 kg/h. The electrocontact method was utilized in the study using a special two-needle probe with replaceable contact heads. In this work, experimental confirmation of the validity of using a logarithmic normal distribution was obtained to describe the dispersed composition of droplets at the swirler inlet. The calculation of the nonnormalized distribution function averaged over the section of the separation device for droplets flying through the interblade channels without interaction with the swirler blades was performed. Graphical dependences of the droplet distribution density function are presented. A calculated ratio is presented to determine the average value of the mass fraction of liquid droplets that does not interact with the swirler blades. The analysis of the dispersed composition of droplets flying through the interblade channels of the swirler without interaction with the blades showed that this phenomenon is typical only for fine droplets.

Visualisation of Droplet Flow Induced by Ultrasonic Dental Cleaning

IntroductionDuring dental treatment procedures ultrasonic scalers generate droplets containing microorganisms such as bacteria and viruses. Hence, it is necessary to study the dynamic properties of generated droplets in order to investigate the risks associated with the spread of infection. The aim of this study was to visualise the flow state of droplets and to evaluate the impact of droplets generated during the use of an ultrasonic scaler during an oral surgical procedure. MethodsWe studied the spatial flow of liquid droplets through a combination of imaging and numeric simulation of a simulated dental treatment processes. First, we photographed the real time images of the ultrasonic scaler and evaluated the images using image-processing software Image J to visualise the flow of liquid droplets. Finally we simulated the flow process of liquid droplets by using the initial velocity of droplet splashing and the angle of the obtained information using computerised fluid dynamics technology. ResultsUnder different working conditions, the droplet particle splashing velocity, maximum height, and spray angle varied, but the particle trajectory was generally parabolic. The maximum droplet velocity varied between 3.56 and 8.56 m/s, and the splashing height was between 40 and 110 mm. ConclusionsDuring risk assessment of an ultrasonic scaler usage, difficulties arise due to the insufficient research on droplet velocity and distribution. This study aims to address this gap by visualising the flow trajectories of droplets generated by ultrasonic scalers. The obtained data will assist in developing more effective interventions based on spatial and temporal distribution of droplets. This provides a new approach for droplet particle research and offers new strategies for public health prevention and control.

Establishment and clinical application of a droplet digital PCR method for the detection of Edwardsiella tarda.

Edwardsiella tarda (E. tarda) can infect humans and a variety of animals, including fish, amphibians, reptiles, birds, and mammals. However, a more highly sensitive, specific, and repeatable test for its detection is lacking. The objective of this study was to develop a highly sensitive, specific, and repeatable droplet digital polymerase chain reaction (ddPCR)-based method for the quantitative detection of E. tarda. The gyrB gene was selected as the target gene, and primers and probe were designed and synthesized. Using E. tarda genomic DNA as templates, the reaction method was optimized to establish a linear relationship with real-time PCR detection methods. The sensitivity, specificity, and repeatability of the method were analyzed, and clinical samples were tested. When the primer and probe concentrations were 900 and 300 nM, respectively, and the annealing temperature was 57°C, the efficiency of the ddPCR amplification reaction was highest and the boundary between positive and negative droplet distribution was clearest. The sensitivity was high, with detection limit being as low as 0.56 copies·μL-1; additionally, and a good linear relationship (R 2 = 0.9962) between ddPCR and real-time PCR detection, within the range of 1-25,000 copies·μL-1, was evident. The repeatability was good, with a detection coefficient of variation of 2.74%. There was no cross-reactivity with 15 other common pathogenic microorganisms in aquatic animals (Streptococcus agalactiae, Streptococcus iniae, Streptococcus suis type 2, Nocardia seriolae, Vibrio parahaemolyticus, Aeromonas sobria, red sea bream iridovirus, decapod iridescent virus 1, enterocytozoon hepatopenaei, carp edema virus, Koi herpesvirus, goldfish hematopoietic necrosis virus, tilapia lake virus, viral nervous necrosis virus, or grass carp reovirus) in positive samples. Among the 48 clinical samples, including Bahaba taipingensis and its live food fish, pond water samples, and routine monitoring samples (Koi), 21 were positive for E. tarda, consistent with the bacterial isolation and identification results. The E. tarda ddPCR detection method has high specificity, sensitivity, and repeatability, can more accurately quantify E. tarda, and provides a useful reference for research related to this bacterium.