Flow Area Research Articles

Sirolimus-eluting iron bioresorbable scaffold versus cobalt-chromium everolimus-eluting stents in patients with coronary artery disease: Rationale and design of the IRONMAN-II trial

BackgroundThe previous first-in-human study established the preliminary safety and effectiveness of the novel thin-strut iron bioresorbable scaffold (IBS). The current study aims to directly compare the imaging and physiological efficacy, and clinical outcomes of IBS with contemporary metallic drug-eluting stents (DES). MethodsA total of 518 patients were randomly allocated to treatment with IBS (257 patients) or metallic DES (261 patients) from 36 centers in China. The study is powered to test noninferiority of the IBS compared with the metallic everolimus-eluting stent in terms of the primary endpoint of in-segment late lumen loss at 2 years, and major secondary endpoints including 2-year quantitative flow ratio and cross-sectional mean flow area measured by optical coherence tomography (OCT) (limited to the OCT subgroup, 25 patients in each group). ConclusionThis will be the first powered randomized trial investigating the safety and efficacy of the novel thin-strut IBS compared to a contemporary metallic DES. The findings will provide valuable evidence for future research of this kind and the application of metallic bioresorbable scaffolds.

Comparative tests of diesel injectors with serial and modernized nozzles

BACKGROUND: More than 60% of agricultural tractor failures are due to diesel engine failure. Half of diesel engine failures occur in the fuel supply system, where the majority is determined by the service life of diesel injector nozzles. AIMS: The purpose of this study was to increase the durability of the nozzle by upgrading the nozzle needle. MATERIALS AND METHODS: To increase the working life of the diesel injector nozzle, a new technical solution was proposed, which consists in applying a screw channel to the bearing surface of the needle. The presence of a screw channel results in axisymmetric pressure on the needle, which gives it increased stability and prevents the possibility of skewing and freezing. A patent has been received for this invention from the Russian. To confirm the expected effect, comparative laboratory tests were carried out with a serial and upgraded atomizer design. To carry out accelerated tests, “dusty” fuel was used, obtained by adding quartz sand abrasive. During the tests, the following were assessed: atomization quality, sealing cone tightness, hydraulic density, needle stroke and effective flow area. The assessment of wear of the mating surfaces of the nozzle depends on the value of the hydraulic density. RESULTS: As a result of the experiment, it was found that for serial injectors the limiting value of hydraulic density occurs after 2500 operating hours and is characterized by a violation of tightness. For modernized injectors, the hydraulic density limit occurs after operating 4300 engine hours. CONCLUSIONS: Applying a screw channel on the bearing surface of the needle allows you to increase the life of the diesel injector by 23.

АЭРОДИНАМИЧЕСКИЙ РАСЧЕТ СИСТЕМЫ ОЧИСТКИ ЗЕРНОУБОРОЧНОГО КОМБАЙНА В 2D-ПОСТАНОВКЕ

The paper presents the methodology of modelling air flows in the flow area of the air-screen cleaning system of a combine harvester in two-dimensional formulation. Recommendations are given on parameters adjustment of the computational fluid dynamics software package Ansys Fluent. An example is provided on aerodynamic calculation of cleaning system two-dimensional model. According to the estimation of the results of experimental studies and modelling, the error was not more than 10 %. Recommendations are formulated on the cleaning system design to obtain uniform airflow across its width. The application of this methodology makes it possible to carry out the model calculation on a personal computer without using clusters or high-performance servers. The obtained results will be subsequently used in further research of the combine harvester cleaning system.

Application of BPNN algorithm in thermal-hydraulic analysis of unwrapped LFR core

Due to the complex structure of the LFR fuel rod bundle, refined CFD simulation consumes significant computing resources and time, making it difficult to meet the immediate needs of engineering design and research. This paper introduces a method that integrates the sub-channel level thermal-hydraulic analysis code CorTAF-LBE with the BPNN algorithm to analyze the thermal-hydraulic phenomena within the LFR core. The method has been validated by refined simulation results of the THEADES test section, which indicate that the error is within an acceptable range. The feasibility of its application in LFR fuel assemblies was also evaluated. The flow characteristics and temperature distribution in unwrapped LFR rod bundles are investigated. Due to differences in fuel distribution and flow area, the temperature in the central channel is much higher than that in the side and trapezoidal channels. Three accident conditions, including inlet blockage, center blockage, and outlet blockage, were simulated. The corresponding peak temperatures of the fuel cladding were 670 K, 767 K, and 860 K, respectively, representing an increase of approximately 170 K compared to the nominal conditions. The analysis results effectively demonstrate the 3D temperature distribution of the fluid in the rod bundles, which is significant for reactor design and safety analysis of LFRs.

Technical Assistance on Plant Cultivation Landslide Prevention in the River Flow Area in Kampung Bendang Nagari River Sariak VII Koto Padang Pariaman District

Technical Assistance on Plant Cultivation Landslide Prevention in the River Flow Area in Kampung Bendang Nagari River Sariak VII Koto Padang Pariaman District

Computational study of the impacts of the nozzle configurations on passive pre-chamber engine combustion

The pre-chamber (PC) nozzle configurations are vital in the narrow-throat pre-chamber design. However, their impacts on the jet and combustion characteristics are poorly understood. In the current study, various parameters of nozzle configurations, including the number of rows, nozzle position, and the jet included angle were evaluated on a well-calibrated numerical model of a passive PC engine fueled with methane. The unique buffering effect of the bottom cavity below the orifice in the PC nozzle was discovered and investigated for the first time. Results show that the PC with double-row orifices exhibits slower general combustion than the single-row for the significant flow bypass from the upper-row orifices that generate low jet velocity. A higher orifice position favors combustion due to less interaction between the flame and the piston. Pressure accumulation at the nozzle was discovered to be the key factor affecting jet velocity. Jet velocity increases with the enlarged pressure accumulation decreasing the effective flow area of the orifices. However, it starts to decrease when the pressure accumulation becomes excessive and the obstruction to the flow outweighs the enhancement to the velocity. For single-row PCs without the bottom cavity, the pressure accumulation is enhanced as the jet included angle increases (from 111° to 180°) and the angle of 157° achieves the highest jet velocity, although the pressure difference decreases as the included angle increases. For single-row-orifice PCs with a bottom cavity, the buffering effect of the cavity produces close pressure accumulation to maintain similar jet characteristics when the jet included angle varies. Comparative analysis shows that the included angle of 157° achieves the fastest main chamber combustion mainly because the proper relative position of the PC jet and piston favors turbulence and flame spread.

Instantaneous flow area calculation for modeling an axial piston pump: A point cloud-based technique

Instantaneous flow area calculation for modeling an axial piston pump: A point cloud-based technique

A Predictive Model for Wellbore Temperature in High-Sulfur Gas Wells Incorporating Sulfur Deposition

HSG (high-sulfur gas) reservoirs are prevalent globally, yet their exploitation is hindered by elevated levels of hydrogen sulfide. A decrease in temperature and pressure may result in the formation of sulfur deposits, thereby exerting a notable influence on gas production. Test instruments are susceptible to significant corrosion due to the presence of hydrogen sulfide, resulting in challenges in obtaining bottom hole temperature and pressure test data. Consequently, a WTD (wellbore temperature distribution) model incorporating sulfur precipitation was developed based on PPP (physical property parameter), heat transfer, and GSTP (gas–solid two-phase) flow models. The comparison of a 2.53% temperature error and a 4.80% pressure error with actual field test data indicates that the established model exhibits high accuracy. An analysis is conducted on the impact of various factors, such as production, sulfur layer thickness, reservoir temperature, and reservoir pressure, on the distribution of the wellbore temperature field and pressure field. Increased gas production leads to higher wellhead temperatures. The presence of sulfur deposits reduces the flow area and wellhead pressure. A 40% concentration of hydrogen sulfide results in a 2 MPa pressure drop compared to a 20% concentration. Decreased reservoir pressure and temperature facilitate the formation of sulfur deposits at the wellhead.

#806 Predicting arteriovenous fistula success using ferumoxytol-enhanced MRI (Fe-MRI) and computational flow dynamics (CFD)

Abstract Background and Aims Arteriovenous fistula (AVF) failure is common and is invariably associated with preexisting anatomic problems of the inflow and outflow circuit. Ferumoxytol, an iron oxide nanoparticle, provides a safe alternative to gadolinium contrast material for MR angiography in chronic kidney disease (CKD). Computational fluid dynamics (CFD) has been utilised to virtually demonstrate the haemodynamics within AVFs using high-quality vascular mapping obtained with ferumoxytol-enhanced MRI (Fe-MRI). Using Fe-MRI and CFD we aimed to assess AVF haemodynamics and identify flow patterns and geometries associated with AVF success. Method In this pilot study we used Fe-MRI datasets of CKD patients who had vascular mapping 6 weeks after AVF creation. Using CFD methods we performed vessel segmentation to construct three-dimensional (3D) patient-specific geometries from images obtained with Fe-MRI (Fig. 1). We then completed a detailed CFD analysis for each AVF geometry to establish the associations of haemodynamic (mean wall shear stress (WSS), oscillatory shear index (OSI), blood flow velocity, and areas of abnormal flow) and anatomical parameters (anastomosis angle, feeding artery diameter, feeding artery curvature, draining vein diameter, and draining vein curvature) with AVF outcomes. The primary outcome was AVF success defined as AVF use (assisted or unassisted) for dialysis for a minimum of 3 months. ROC analysis was used to assess anatomical predictors of AVF flows of ≥1000 ml/min. Results The study included 17 patients with CKD who had AVF creation between 2018 and 2020. From these, 13 AVFs were successfully used for dialysis and 4 failed to mature or were used for dialysis for <3 months before failure. Compared to failed fistulas, successful AVFs had higher mean WSS and OSI. Failed AVFs were characterised by different haemodynamic patterns including lower flow rates with less helical flows. On ROC analysis the three metrics with the highest area under the curve (AUC) values were the feeding artery curvature (0.82), feeding artery diameter (0.76), and draining vein diameter (0.74) with a combined AUC value of 0.83 (Fig. 2). Conclusion Using Fe-MRI and CFD in the post-surgical juxta-anastomotic environment higher mean WSS and OSI were predictive of AVF success. In addition, the feeding artery curvature, feeing artery and draining vein diameters are strongly correlated with high venous flow rates, one of the key factors of AVF success. Although vessel diameters are routinely measured as part of pre-operative vascular mapping, a greater emphasis should be given on mean WSS, OSI and feeding artery vessel curvature when selecting vessels for AVF creation.

A Study on the Interaction Between Population Mobility and High-Quality Development of Manufacturing Industry in China —Based on the Data of Fujian Province

This paper uses relevant mathematical statistical models to verify the interactive effect between population mobility and the high-quality development of the manufacturing industry based on the panel data of 43 counties in the Fujian province from 2007 to 2021. The results show that (1) the inflow areas of population flow in the Fujian province are mainly concentrated in the southeast region; (2) there is mutual promotion between population mobility and the high-quality development of the manufacturing industry in the Fujian province, and the population mobility in adjacent areas has a significant promotion effect on the high-quality development of the local manufacturing industry; and (3) heterogeneity results show that after 2011, the interaction effect between population mobility and the high-quality development of the manufacturing industry has declined, and population inflow has a stronger role in promoting the high-quality development of the manufacturing industry than population outflow. The conclusions of this study are of great significance to the Fujian province for implementing a reasonable population policy and promoting the coordinated development of manufacturing enterprises.

Machine learning approaches to debris flow susceptibility analyses in the Yunnan section of the Nujiang River Basin.

The Yunnan section of the Nujiang River (YNR) Basin in the alpine-valley area is one of the most critical areas of debris flow in China. We analyzed the applicability of three machine learning algorithms to model of susceptibility to debris flow-Random Forest (RF), the linear kernel support vector machine (Linear SVM), and the radial basis function support vector machine (RBFSVM)-and compared 20 factors to determine the dominant controlling in debris flow occurrence in the region. We found that (1) RF outperformed RBFSVM and Linear SVM in terms of accuracy, (2) topographic conditions were prerequisites, and geology, precipitation, vegetation, and anthropogenic influence were critical to forming debris flows. Also, the relative elevation difference was the most prominent evaluation factor of debris flow susceptibility, and (3) susceptibility maps based on RF's debris flow susceptibility (DFS) showed that zones with very high susceptibility were distributed along the mainstream of the Nujiang River. These findings provide methodological guidance and reference for improvement of DFS assessment. It enriches the content of DFS studies in the alpine-valley areas.

Aerodynamic Stability Enhancement of a Sco2 Centrifugal Compressor by Riblets of the Shroud

Abstract This paper investigates the mechanism of aerodynamic instability of shrouded SCO2 compressors and accordingly proposes a new method for stability enhancement via the casing treatment in terms of shroud riblets. Firstly, the experimentally validated CFD method is employed to investigate the flow mechanism of the compressor under near-surge condition. The significant backflow phenomena within the impeller were revealed. Further analysis indicated that the imbalance of the Coriolis force and pressure gradient in blade-to-blade direction pushed the low-momentum fluid toward the shroud suction side. Additionally, higher Reynolds number resulted in thinner SCO2 boundary layer at the inlet near end-wall, increasing passage vorticity and further intensifying the aggregation of low-energy fluid on the shroud suction side. Based on the flow mechanisms, the streamwise riblets on shroud were designed to impede the migration of low-energy fluid. The CFD results revealed that under low-flow condition, riblets inhibit the formation of inducer vortices and backflow, enhancing impeller aerodynamic stability and reducing the surge mass-flow rate. Further research indicated that riblets obstruct the migration of low-energy fluid towards shroud suction side, reducing the accumulation of low-energy fluid and blockage, thereby increasing the flow area and aerodynamic stability. Moreover, additional riblets wake and friction losses contributed to the deterioration of compressor performance at middle/large mass-flow-rate conditions. Specifically, riblets reduced the flow area between blades at near choke mass-flow rate, leading to more pronounced shock structures and compressor earlier choke.

Coupling Global Parameters and Local Flow Optimization of a Pulsed Ejector for Proton Exchange Membrane Fuel Cells

Proton exchange membrane fuel cells (PEMFCs), as an important utilization of hydrogen energy, contribute to the sustainable development of global energy. Pulsed ejectors have a high potential for improving the hydrogen utilization of PEMFCs in the full operating range by circulating unconsumed hydrogen. In this study, a pulsed ejector applied to a 120 kW fuel cell was designed, and the flow characteristics were analysed using computational fluid dynamics (CFD). Based on the data from the CFD model, the global optimization of the ejector was carried out using the Gaussian process regression (GPR) surrogate model and the grey wolf optimization (GWO) algorithm. The local structure was then further optimized using an adjoint method coupling streamlining modification that takes into account the local flow characteristics. The CFD results showed that, under a fixed structure, increasing the pressure difference between the secondary flow and the ejector outlet would promote boundary layer separation, shorten the shockwave chain length, change the effective flow area of the secondary flow, and lower the entrainment ratio (ER). The analytical results from the GPR model indicated significant interactions among the structural parameters. The globally optimized ejector using GPR and GWO improved the hydrogen entrainment ratio from 1.42 to 3.12 at the design point. Furthermore, the results of streamlining local optimization show that the entrainment ratio increased by 1.67% at the design point and increased by up to 3.99% over the full operating range compared to the optimized ejector by global optimization.

Study of geomechanical properties of the Pimienta formation with undrained multi-stage triaxial tests, Central-Western Tampico Misantla Basin, Mexico

The Pimienta Formation (J-Pi) of the Tampico Misantla Basin (TMB) in Mexico is known for its potential as unconventional onshore hydrocarbon reserves. The area of interest in this study is located in the western-central part of the TMB, where no significant production has been established from unconventional resources. Given the low permeability and low porosity characteristics of the carbonaceous mudstone in the Pimienta formation, it is necessary to implement techniques to increase the area of flow from the reservoir to the borehole, achieving profitable oil and gas extraction.The geomechanical properties of rock strata are essential inputs for the design and implementation of shale oil and gas production engineering, such as horizontal drilling and hydraulic fracturing. Understanding the capabilities of the rock to yield and contain hydraulic fractures is essential to designing safe and efficient well stimulations. Likewise, the wellbore stability is of critical importance to the successful development of secondary and tertiary recovery systems.In this study, core samples from the Pimienta Formation in the TMB are analyzed through undrained multi-stage triaxial tests, emphasizing the estimated in-situ geo stresses and the effect of the mineral composition of the rock. The geomechanical parameters of compressional strength, Poisson ratio (PR), and Young's modulus of the Pimienta formation are obtained from the analysis of the experimental data and finding correlations to the mineral composition of the samples. A detailed characterization is completed under the conventional rock mechanics methodologies of Mohr-Coulomb and Hoek-Brown failure criterion, as well as Brittleness Index (BI).

Homogenized color-gradient lattice Boltzmann model for immiscible two-phase flow in multiscale porous media

In this paper, a homogenized multiphase lattice Boltzmann (LB) model is established for parallelly simulating immiscible two-phase flow in both solid-free regions (pore scale) and porous areas (continuum scale). It combines the color-gradient multiphase model with the Darcy–Brinkman–Stokes method by adding a term that includes surface force and drag force of porous matrix to multiple-relaxation-time LB equation in moment space. Moreover, an improved algorithm is proposed to characterize and implement the apparent wettability in the locally homogenized porosity field. Validations and test cases are given to demonstrate the accuracy and robustness of this new model, as well as its applicability for trans-scale fluid simulation of transport and sorption behavior from porous (Darcy flow) area to free (Stokes flow) area. For practicality, the two-phase seepage flow in a composite rock structure with multiscale pores is simulated by this new model, and the effects of viscosity ratio and wettability on the displacement process are discussed.

Effects of airflow direction on the thermal-hydraulic performance of louvered fin-common flow up vortex generator

To improve the thermal-hydraulic performance of the louvered fin and flat tube heat exchangers (LFHEs), this paper innovatively proposes the louvered fin-common flow up vortex generator (LF-CFUVG). Then, numerical simulations are conducted to study the effects of airflow direction γ on the thermal-hydraulic performance of the LF-CFUVG. The corresponding results indicate that the flow resistance of the LF-CFUVG is always greater than the Baseline (the LFHE without CFUVGs), as the CFUVGs reduce the minimum free flow area while forming low-speed wake zones behind them. The heat transfer capacity of the LF-CFUVG exceeds the Baseline as well, this is attributed to the longitudinal vortices induced by the CFUVGs, which is helpful to homogenize the temperature field and transport the high-speed and low-temperature airflow. And the thermal-hydraulic performance of LF-CFUVG also outperforms the Baseline. In comparison to the working condition of γ is 0°, the pressure drop Δp for the LF-CFUVG declines with increase of γ from 0° to 30°, thus a larger angle helps to reduce flow resistance. However, the heat transfer coefficients hLF and performance evaluation criteria (PEC) of the LF-CFUVG deteriorate with the increasing γ, so a smaller angle is recommended to obtain an intenser heat transfer and better PEC.

Exercise may be a Novel Strategy to Reduce Vascular Toxicity of Immune Checkpoint Inhibitors in a Mouse Melanoma Model

Background: Immune checkpoint inhibitors (ICIs) are a cornerstone in advanced melanoma treatment. Unfortunately, ICI-associated cardiovascular toxicity, particularly atherosclerotic events, poses a significant challenge. Identifying interventions to mitigate the cardiovascular toxicity of ICI is critical for enhancing the quality and duration of life in cancer survivors. Given the established benefits of exercise in atherosclerosis prevention, this study explores its potential to reduce ICI-induced vascular toxicity in the context of melanoma. We hypothesized that aerobic exercise would decrease ICI's vascular toxicity in a mouse melanoma model. The primary experimental outcome was endothelial mesenchymal transition (EndMT), an early atherosclerosis indicator. Methods: C57BL/6 mice were subcutaneously injected with 0.8 x 106 BP melanoma cells ( BrafV600E/WT and Pten−/−). Upon tumor palpability, mice were assigned into four groups: IgG, Exercise, anti-PD-1, and anti-PD-1+Exercise. Mice were treated with bi-weekly administration of anti-PD-1 or IgG antibody (150 μg) for three weeks, combined with or without treadmill exercise (12 meters/minute for 45 min per day, five days/week). Body weight was monitored weekly. Following the final treatment, aortic tissues were collected and en face immunofluorescence staining for endothelial marker VE-cadherin (VE-Cad) and vimentin was performed to assess EndMT, then analyzed via confocal microscopy. Results: No significant weight differences were observed between groups. Notably, the EndMT marker vimentin expression was significantly higher in anti-PD-1 treated tumor-bearing mice compared to IgG controls (3.8% vs 0.6%, p=.03) in the atheroprotective laminar flow area. This was reduced by exercise; the anti-PD-1+Exercise group showed significantly reduced endothelial vimentin levels relative to the anti-PD-1 alone (0.8% vs 3.8%, p=.04). Disturbed flow areas did not exhibit notable differences between any group. Conclusions: Aerobic exercise may be protective against vascular toxicity in mice treated with ICIs by promoting atheroprotective flow and potentially inhibiting EndMT. Although these initial results are promising, comprehensive studies are required to ascertain the impact of exercise on preventing ICI-induced EndMT and subsequent atherosclerosis in this mouse melanoma model. Future research will aim to more deeply characterize the process of EndMT following ICI treatment and evaluate the preventive capacity of exercise against atherosclerosis in this context. MD Anderson Cancer Center Melanoma SPORE grant (NCI P50CA221703-05). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Experimental study on Local Scour around Bridge Pier Models generated by Flash Floods carrying Debris

The analysis of local scouring around bridge piers currently is based on typical river flood discharges. However, extreme events like flash floods with high velocity and discharge, carry wooden debris that accumulates upstream of the bridge pier. This results in additional forces due to flow diversion and reduction in flow area, so impacting hydraulic structures and exacerbating the scouring process. The study objective was to examine the impact of debris transported by flash floods on the depth and distribution patterns of scouring around bridge piers. This research was conducted in a 15.5-m-length, 0.5-m-width, and 1.0-m-height glass flume, layered by 25 cm thick of sand which is d50=0.52 mm and σg=2.327. Flash flood simulations were conducted by flowing the water mixed with debris content of 0, 5, 10, and 15% to hit a sharp nose pier model which is installed in the channel. Scour depth was measured using point gauges at 50 points around the pier. The findings indicated that an irregular distribution pattern of scour is formed around the pier, and scour depth decrease when increasing debris content. It is necessary to corrected in the range of 0.65-1.43 for 0-15% debris content carried by the flash flood compared to normal flood.

Abstract 3138: Atheroprone Flow, Aging, And Oxysterols Impair Endothelial Cell Nuclear Health Via Disruption Of Autoregulatory Perinuclear Cytoskeletal Dynamics

The vascular hemodynamic environment plays a well-known role with progressive pathological conditions such as atherosclerosis, hypercholesterolemia, and aging. Our lab has previously shown that the exposure of oxysterols to endothelial cells (ECs) causes increased cell stiffening. This stiffening effect is compounded when the hemodynamic environment changes from atheroprotective laminar flow to atheroprone oscillatory flow. The increasing EC stiffening demonstrates that these disruptive effects significantly alter cellular biomechanics. The complexity of events associated with these altered biomechanical states leaves many questions unanswered about spatiotemporal changes in the biomechanical structures of endothelial cells exposed to a varying hemodynamic environment and oxysterols. To address this void, we observed the effects of 7-Ketocholesterol exposure (a major oxysterol) on the primary cytoskeletal/biomechanical components (F-actin, Microtubules, Intermediate Filaments, etc.) of human aortic endothelial cells during various time points of laminar/oscillatory flow conditions through a combination of sophisticated multiplexed 6-color labeling, ultra-high resolution 3D microscopy, 3D computer vision, and machine learning. Additionally, we applied these techniques to extracted aortic tissues from young and aged mice (on low fat diet vs high fat diet) and focused on obtaining information from both the laminar flow areas (descending aorta) and the oscillatory flow areas (aortic arch). Our findings demonstrate that oxysterol exposure and aging cause significant remodeling & alteration of crucial endothelial cytoskeletal/biomechanical components and that these alterations are unique to each combinatorial condition. Notably, we find that cytoskeletal remodeling associated with endothelial stiffening is accompanied by major nuclear distortion, a hallmark of aging and senescence which subsequently causes DNA damage and genomic instability. We also find that this nuclear distortion is driven by dynamic biomechanical changes and mediated by the hemodynamic environment, where atheroprotective flow promotes cytoskeletal configurations protecting the nuclei, and atheroprone flow promotes cytoskeletal configurations that leave the nuclei unprotected.

Research on alien invasive plants in Jingzhou County, Hunan Province, China

Harm from alien invasive plants is increasing in Jingzhou County, Hunan Province. Based on a one-year field investigation and available literature, we investigated species composition, origin, flora, degree of harm and distribution pattern of invasive plants in the county. The results showed that there were 34 invasive plant species from 27 genera and 16 families in this County. The dominant invasive species belonged to Asteraceae (8 species) and Amaranthaceae (6 species), which accounted for 23.5% and 17.7%, respectively. The majority of invasive plants originated from South America (45.7%) and North America (30.4%). Tropical flora showed a significantly higher representation than temperate flora, signifying robust tropical characteristics amongst the invasive plant population. Based on hazard level classification, we recognized four types as malicious invasion (Level 1): Alternanthera philoxeroides, Erigeron annuus, E. canadensis, and Xanthium chinense. In addition, five types were classified as severe invasion (Level 2), eight types as local invasion (Level 3), fifteen types as general invasion (Level 4), while two types were still under observation (Level 5). The pattern of distribution demonstrated that invasive plants in Jingzhou County mostly spread along the verges of transportation roads, in human settlements, and in a few areas of water flow. The higher levels of invasion damage were principally concentrated in the central part of Jingzhou County.