Regulation Of Flow Research Articles

PROBLEMS OF ENVIRONMENTAL SECURITY AND WATER SUPPLY NEEDS IN THE CENTRAL ASIAN REGION

he last decade in the Central Asian region has been characterized by a steady trend of increasing fresh water needs due to the expansion of agricultural activities and the growth of population consumption. At the same time, the growth of consumption is ensured exclusively by increasing the anthropogenic load on available water resources, which causes a multiple increase in the risks of environmental disasters and problems with water supply and ensuring water security of the countries of the region. The article uses the method of complex assessment (balance method) of assessing the level of water resources availability in the context of countries, content analysis of regulation of water use of transboundary rivers, factor analysis of the growth of regulation of water flows of the main rivers (Amu Darya and Syr Darya basins, hereinafter abbreviated as BAM) and project analysis of the growth of anthropogenic pressure on the resource base of the region. The study notes that the uncoordinated use of water resources for national development and projects to overcome the environmental problems of shallowing of the Aral Sea only lead to an aggravation of the situation. The conclusions are based on the assessment of projects and strategies for overcoming the environmental catastrophe of the Aral Sea and the construction of new artificial water drainage infrastructure in the countries of the lower reaches of transboundary rivers.

Focusing on microvascular function in heart failure with preserved ejection fraction.

Heart failure is a prevalent global health issue. Heart failure with preserved ejection fraction (HFpEF), which already represents half of all heart cases worldwide, is projected to further increase, driven by aging populations and rising cardiovascular risk factors. Effective therapies for HFpEF remain limited, particularly due to its pathophysiological heterogeneity and incomplete understanding of underlying pathomechanisms and implications. Coronary microvascular dysfunction (CMD), characterized by structural and functional changes in the coronary microcirculation, is increasingly recognized as a significant factor in HFpEF even though the exact nature of their causal relationship is still unclear. This review explores prevalence, prognostic implications, and potential therapeutic targets for CMD in HFpEF. CMD's role in HFpEF might involve impaired coronary blood flow regulation, leading to myocardial ischemia, impaired relaxation, and/or adverse remodeling. Vice versa, increased wall stress in patients with HFpEF might elevate coronary resistances, further worsening microvascular perfusion. Finally, abnormalities in substrate metabolism might cause both CMD and HFpEF. Current treatments, including pharmacotherapy and device-based therapies, show limited success, highlighting the need for more targeted approaches. New possible therapies, such as the coronary sinus reducer device, may show promise in improving myocardial perfusion and function. However, further large-scale studies are required to elucidate the mechanistic links between CMD and HFpEF and to develop specialized treatments for distinct heart failure phenotypes.

Assessment In Depth on the Anti‐seasonal Water Fluctuations and Vegetation Dynamic Trends in a Plateau Lake, Southern China

ABSTRACTHuman activities, such as dam construction for flow regulation, modify the natural hydrological regimes of lakes and rivers. The altered flow regimes substantially influence plant growth in the water level fluctuation zone, impacting both vegetation patterns and success. The relationships among above‐ground vegetation, soil seed bank and soil microorganisms remain unexamined. This study was performed in Lashi Lake, a plateau lake in southern China characterized by anti‐seasonal water level fluctuations, and Jizi Reservoir, a reference site exhibiting natural seasonal water level variations. The primary aim was to assess the distribution pattern of plant, soil seed bank and their corresponding soil microorganism over the three flood gradients, and the relationships among them were analysed simultaneously. The findings indicated that both plant community variety and seed bank diminished as the area of soil flooding increased. The soil seed bank was a strong indication of community diversity, particularly throughout late spring and late summer. Additionally, significant correlations between the alpha diversity of soil microorganisms and the concentrations of soil carbon, nitrogen and moisture were found across the flooding gradients. The organization and diversity of soil microbial communities were significantly correlated with the alpha diversity of the plant community and the soil seed bank. The findings demonstrate that both seed banks and soil bacteria play a dynamic role in the restoration of vegetation in areas experiencing anti‐seasonal water fluctuations.

Using a Theoretical Model to Assess the Impact of Vascular Risk Factors on Autoregulation in the Retina.

Vascular impairments, including reduced capillary density (CD), impaired autoregulation capacity (Reg), and elevated intraocular pressure (IOP), have been identified as significant contributors to glaucomatous disease. This study implemented a theoretical model to quantify the impact of these impairments on retinal blood flow and oxygenation as intraluminal pressure (Pa) is varied. A theoretical model of the retinal vasculature was used to simulate reductions in CD by 10% (early glaucoma) and 30% to 50% (advanced glaucoma), a range in autoregulation capacity from 0% (totally impaired) to 100% (totally functional), and normal (15mm Hg) and elevated (25mm Hg) levels of IOP. Under baseline conditions of CD = 500mm-2, Reg = 100%, and IOP = 15mm Hg, an autoregulation plateau was predicted for Pa = 28 to 44mm Hg. Decreased CD, impaired flow regulation mechanisms, and increased IOP all cause a loss of the autoregulation plateau and a corresponding decrease in tissue oxygenation in this pressure range. Although the detrimental effects of small decreases in CD or elevations in IOP are mostly offset by functional flow regulation, larger changes and/or combinations of vascular impairments lead to a significant drop in retinal oxygenation. Model predictions indicate that isolated or combined vascular impairments in CD, flow regulation, and IOP contribute to poor retinal tissue oxygenation, which could lead to vision loss in advanced glaucoma patients. This study motivates early identification of vascular changes to prevent a substantially worse effect of these factors on retinal oxygenation during the progression of glaucoma.

Necrotizing Enterocolitis: Pathogenetic Features and Differential Diagnosis with Inflammatory Bowel Disease in Newborns

Necrotizing enterocolitis (NEC) is a disease primarily affecting premature infants. NEC pathogenesis is based on the development of inflammation damaging mucous membranes associated with bacterial colonization, intestinal epithelium immaturity, intestinal blood flow regulation, and excessive inflammatory response activation. Inflammatory bowel disease (IBD) with very early onset (VEO-IBD) can also manifest in the neonatal period. They are characterized by severe course, often resistant to traditional immunosuppressive therapy. This article discusses the features of NEC pathogenesis and differential diagnosis with VEO-IBD. Despite certain similarities in pathogenesis, NEC and IBD are different diseases. Infantile onset IBD is more often associated with monogenic diseases and primary immunodeficiency. VEO-IBD is a chronic disease characterized by damage to all intestinal layers and has a lower incidence compared to NEC. Its clinical manifestations may include chronic diarrhea, blood in stool, delayed physical development, perianal diseases, and ulcerations in the oral cavity. Infantile onset VEO-IBD usually affects the colon, while NEC affects the ileum in premature infants. The intestinal microbiome in VEO-IBD also has specific features. It has been reported that clinical cases of Crohn’s disease in patients who had NEC in the neonatal period are associated with NEC surgery. It is crucial to consider perinatal period features when assessing the IBD risk (prenatal effects of antibacterial therapy and smoking, several courses of antibacterial therapy during the first year of life, and formula feeding).

Influence mechanisms of the submerged sand engine on coastal protection as the extension of beach nourishment

As an innovative practice of beach nourishment, a submerged sand engine was constructed for coastal restoration in Jinsha Bay, China. The submerged sand engine is composed of a nourished beach, submerged sand groins and submerged sandbars. To investigate hydrodynamic and geomorphological responses to the system, a multi-coupled model is established for numerical simulations. The numerical results indicate that the submerged sand engine serves structural functions in wave attenuation and flow regulation. The system reduces significant wave heights of storm waves by 79% at most, and mitigates alongshore current speed in embayed areas by a 10% decrease in the embayed area. In a typical typhoon event, the system reduces erosion spots with erosion depth over 0.09 m by 100% along embayed beaches. Moreover, submerged sandbars serve similar contributions on cross-shore and alongshore sediment supplements, while alongshore contributions of submerged sand groins are over 75%. Hence the cross-shore profiles generally present shoreward movement of submerged sandbars and head scour of submerged sand groins. Furthermore, the submerged sand engine saves 90% expenses of the Sand Engine in terms of the sand volume cost per unit length of the target shore. The submerged sand engine is of flexible and economic advantages in coastal protection.

Sheath-enhanced concentration and on-chip detection of bacteria from an extremely low-concentration level.

Microfluidic-based sheath flow focusing methods have been widely used for efficiently isolating, concentrating, and detecting pathogenic bacteria for various biomedical applications due to their enhanced sensitivity and exceptional integration. However, such a microfluidic device usually needs complicated device fabrication and sample dilution, hampering the efficient and sensitive identification of target bacteria. In this study, we develop and fabricate a sheath-assisted and pneumatic-induced nano-sieve device for achieving the improved on-chip concentration and sensitive detection of Staphylococcus aureus (MRSA). The optimized nanochannel design with diverging configuration is beneficial to the regulation of the hydrodynamic flow while the sheath flow is focusing the sample to the confined region as expected. Per the experimental finding, a high flow ratio (sheath flow/sample flow) presents enhanced target concentration by comparing with a low flow ratio. With this setup, MRSA bacteria with an extremely low concentration of ∼100 CFU mL-1 are successfully and sensitively detected under a fluorescence microscope, less than 30 min, demonstrating a reliable sheath-enhanced concentration and on-chip detection for target bacteria. Additionally, the theoretical model introduced here further rationalizes the working principle of our nano-sieve device, potentially guiding the optimization of next generation devices for highly sensitive and accurate on-chip bacteria detection at a much lower concentration level below 100 CFU mL-1.

The impact of endogenous N/OFQ on DPN: Insights into lower limb blood flow regulation in rats

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes, often accompanied by impaired vascular endothelial function in the lower limbs. This dysfunction is characterized by a reduced vasodilatory response, leading to decreased blood flow in the lower limbs and ultimately contributing to the development of diabetic peripheral neuropathy. To delve deeper into this pathological process, the study employed bioinformatics to identify and analyze genes highly active in DPN. The investigation revealed that Membrane metallo-endopeptidase (MME) was effectively mitigated by its antagonist. Male Sprague-Dawley (SD) rats served as the model to systematically explore the intrinsic connection among the nociceptible/orphanin FQ-N/OFQ receptor (N/OFQ-NOP) system, femoral artery blood flow in the lower extremities, MME, and DPN. The rats were randomized into two groups: a control group and a DPN group induced by a single intraperitoneal injection of 55 mg/kg streptozotocin (STZ), with 6 rats in each group. The findings indicated that compared to the control group, the DPN group exhibited a significant reduction in femoral artery blood flow. This was accompanied by a notable increase in serum N/OFQ concentration, heightened expression of opioid-related nociceptive protein receptor 1 (OPRL1) and MME in femoral artery tissues of the lower limbs, and an elevated sciatic nerve stimulation threshold. These results suggest that the serum N/OFQ level in DPN rats is increased, which may promote the occurrence of peripheral neuropathy by up regulating MME and reducing peripheral flow distribution.

Importance of vascularity and blood flow in the reproductive system of female birds: a review

<b><p>The reproductive system of female birds is characterized by a high metabolic rate associated with production of the egg constituents, i.e. the yolk in the ovary, and the albumen and calcified shell in the oviduct. Both organs require a high level of vascularization and intense blood flow, which differs depending on their activity. The increasing expansion of the vascular system and blood flow within the follicle wall as it develops facilitates the rapid delivery of oxygen, hormones, growth factors, nutrients, and egg-yolk precursors to the oocyte. The network of blood vessels is established during angiogenesis, a very complex process involving numerous regulators, the most important, of which are vascular endothelial growth factor and its receptors. Although angiogenesis is an essential process for the normal functioning of the female reproductive system, information about this event in birds is limited. This review aims to provide up-to-date information on the importance of proper vascularization, mechanisms of angiogenesis, and blood flow regulation within the reproductive system of hens. </b></p>

Predicting fine-scale downstream migratory movement of Atlantic salmon smolt (Salmo salar) in front of a hydropower plant

The Atlantic salmon (Salmo salar) is an iconic species of significant ecological and economic importance. Their downstream migration as smolts represents a critical life-history stage that exposes them to numerous challenges, including passage through hydropower plants. Understanding and predicting fine-scale movement patterns of smolts near hydropower plants is therefore essential for adaptive and effective management and conservation of this species. We present a spatially explicit individual-based model for predicting the movement of Atlantic salmon smolts in regulated rivers in Norway, parameterised for smolt movements in the River Mandal and the River Orkla. The model is rooted in statistically derived relationships between observed smolt swimming behaviour and the hydraulic variables they encounter. The aim of the model was to provide fast yet representative swimming patterns past hydropower plants, based on the hydraulic conditions experienced by the smolts. The model outperformed a ‘drift-only’ model in portraying observed swim tracks when comparing simulated and observed tracks. It was found to represent smolt swimming behaviour well. Our results show that by constructing swim models using relatively simple and general statistical relationships between smolt swimming behaviour and the hydraulic environment, we can produce fast and relevant outputs for an adaptive management process, aimed at exploring how physical implementations or changes in flow regulations might affect smolt populations.

Research on the Integrated Converter and Its Control for Fuel Cell Hybrid Electric Vehicles with Three Power Sources

Separate DC-DC converters for each energy source are typically configured in fuel-cell hybrid vehicles. This results in a complex control structure of the powertrain system, low energy density of the converter, and high cost due to the large number of components. Conducting research on DC-DC converters with good energy flow management and high integration is a trend to solve such problems. Based on the analysis of the basic functional structure of the converter, this paper designs a buffering unit circuit with energy collection and distribution functions and appropriately connects it with the pulse unit circuit of the converter. Through device optimization reuse and power transmission path integration, a class of non-isolated four-port DC-DC converters is constructed, which consists of an auxiliary energy charging module, input energy source control module, braking energy feedback module and forward bootstrap boost circuit. This converter has two bi-directional ports, a uni-directional input and a bi-directional output, for separate connection to the power batteries, supercapacitors, fuel cells and DC bus. It can adapt to the fluctuation of the vehicle’s driving condition while achieving dynamic and flexible regulation of power flow and can flexibly allocate power according to the load current and voltage level of energy. It can realize a total of 14 operation modes, including six output power supply operation modes, five auxiliary power charging operation modes, and three braking energy regeneration operation modes. Furthermore, the mathematical model of this converter is constructed using the state-average method and the small-signal modeling method in order to achieve the responsiveness and stability of switching multiple operating modalities. The PI control parameters are optimized using the particle swarm optimization algorithm to achieve optimized control of the converter. The simulation system is set up using MATLAB R2024a to verify that the proposed converter topology and algorithm can dynamically allocate appropriate current paths to manipulate the power flow under various operating conditions, effectively improving the utilization rate and efficiency of energy. The converter has the characteristics of high gain and high power density, which is suitable for three-energy fuel cell hybrid electric vehicles.

Variability of methane content and fluxes in the rybinsk reservoir based on field observations in different seasons of the year

The formation of methane fluxes in the Rybinsk reservoir and the variability of its content in water were investigated during several field campaigns on the reservoir in different seasons. The Rybinsk reservoir is a very large, relatively shallow, low-flow, mesotrophic-eutrophic, morphologically complex basin-valley type reservoir with perennial flow regulation, created on the Upper Volga in 1941. In total, water and air sampling was carried out at 71 stations to determine methane concentration, which was combined with measurements of water column characteristics . As a result, a network of reference stations was established, where regular measurements are made, as well as additional stations in the water area and river estuaries. For control purposes, water samples were taken at the hydroelectric power plant units and downstream of the Sheksninskaya HPP dam, placed within the Rybinsk city. In general, the Rybinsk reservoir is characterised by relatively low methane concentrations - at most stations the average content of dissolved CH4 in water does not exceed 20 µl/l. The lowest concentrations were observed during the winter period. Methane fluxes from the surface of the Rybinsk reservoir vary from 4 to 718 mgC-CH4 m-2 day-1. Specific fluxes in summer period are larger than those measured in autumn, also in summer the spatial variability of the measured fluxes is more significant. Flux values depend on reservoir stratification, oxygen content in water, organic matter in bottom sediments and other factors. Methane degassing through the dam is significantly less than the fluxes from the surface.

Water flow regulation and incentives for conservation: Coca river - ecuadorian Amazon

Conservation and land use policies are key to regulating water in watersheds, influencing water quantity, quality and storage, and mitigating risks such as erosion and flooding. In Ecuador, the Socio Bosque Program (SBP), part of the Good Living Development Plan (2013-2017), focused on conservation without fully considering water benefits. To optimize its implementation, the upper basin of the Coca River, relevant for its hydroelectric potential, was evaluated by analyzing the inclusion of water criteria in the SBP. Four scenarios of land cover and land use change were developed using the Delphi method: Business as Usual (BAU), Strengthening of SPB (SBPS), National Incentive Plan (NIP), and Degradation (DEG). Runoff rates were estimated for each scenario using a land cover and land use model (TerrSet) and a hydrological model (SWAT). The results show that BAU and DEG cause a decrease in lateral and base flow and an increase in surface runoff, while NIP is the only scenario that maintains water regulation. This highlights the need for future incentives to prioritize strategic areas for water regulation in line with watershed management objectives.

The role of sympathetic control in bone vasculature: insights from spinal cord injury.

Bone vasculature is richly innervated by an extensive network of sympathetic nerves. However, our understanding of bone blood flow regulation and its contribution to human bone health is limited. Here, we further our previous findings by characterizing bone vascular responses in the absence of sympathetic control - studying individuals with spinal cord injury (SCI), a population with known peripheral sympathetic disruption. We assessed tibial vascular responses to isometric handgrip exercise (IHE) in individuals with SCI (n = 12) and controls (n = 12). When sustained to fatigue, IHE increases perfusion pressure and sympathetic vasoconstriction in the non-active tissues of the legs. During IHE, we measured blood pressure, whole leg blood velocity via ultrasound, and tibial perfusion (as hemoglobin content) via near-infrared spectroscopy. Controls demonstrated active sympathetic vasoconstriction in the whole leg (i.e., increased vascular resistance, arterial pressure/leg blood velocity) and tibia (i.e., decreased hemoglobin). In contrast, SCI individuals demonstrated modest whole leg vasoconstriction with lesser increases in vascular resistance than controls (P<.04). Tibial vasculature evidenced absent or blunted vasoconstriction compared to controls (P<.01), indicated by increasing tibial hemoglobin until plateauing at higher pressure levels. This suggests that, in the absence of sympathetic control, tibial vascular response may involve other regulatory mechanisms like myogenic vasoconstriction. Lastly, we leveraged existent whole-body Dual Energy X-ray Absorptiometry scans in a subgroup of nine individuals with SCI and we found a strong relationship between leg bone mineral density (BMD) and tibial hemoglobin at end of IHE (r2 = 0.67, P<.01). Our findings indicate that in the absence of sympathetic mechanisms, myogenic control may play a compensatory role in regulating blood flow, though to a lesser extent in bone compared to muscle. The close relationship between lesser declines in bone blood content and higher BMD underscores the link between blood flow and bone health.

The Design and Performance Investigation of a Split Four-Track Water-Jet Cleaning Robot for Steel Gate Panels

Steel gates are widely used in river and sea engineering to ensure water retention and flow regulation. Due to the attachment and the alternation of dry and wet environments, water retention easily causes corrosion and destruction, while the attachment is mainly cleaned manually at present. Based on stable adsorption, wall adaptability, and movement ability, a split four-track cleaning robot was developed. The split structure combined with a body swing and torsion mechanism can increase the degree of freedom of attitude adjustment and realize stable crawling of the curved panel. Considering the impact force of the water jet during cleaning, mechanical analysis of robot instability and driving torque on a curved surface was constructed to solve the problem of safe adsorption and flexible movement. A remote control system is constructed to complete the cleaning operation, and the coordination relationship between cleaning and crawling speed is analyzed. The performance test results show that the robot can crawl flexibly and stably on a curved surface, and the crawling speed can be greater than 0.052 m/s when the load is less than 5 kg. A continuous cleaning process has an obvious effect on silt and shellfish attachments, and the robot can meet the actual operational needs. The design process can help in the development of this kind of robot.

Efficacy of Transcranial Direct Current Stimulation (tDCS) on Neuropsychiatric Symptoms in Multiple Sclerosis (MS)-A Review and Insight into Possible Mechanisms of Action.

Introduction: Neuropsychiatric symptoms such as depression and anxiety are a significant burden on patients with multiple sclerosis (MS). Their pathophysiology is complex and yet to be fully understood. There is an urgent need for non-invasive treatments that directly target the brain and help patients with MS. One such possible treatment is transcranial direct current stimulation (tDCS), a popular and effective non-invasive brain stimulation technique. Methods: This mechanistic review explores the efficacy of tDCS in treating depression and anxiety in MS while focusing on the underlying mechanisms of action. Understanding these mechanisms is crucial, as neuropsychiatric symptoms in MS arise from complex neuroinflammatory and neurodegenerative processes. This review offers insights that may direct more focused and efficient therapeutic approaches by investigating the ways in which tDCS affects inflammation, brain plasticity, and neural connections. Searches were conducted using the PubMed/Medline, ResearchGate, Cochrane, and Google Scholar databases. Results: The literature search yielded 11 studies to be included in this review, with a total of 175 patients participating in the included studies. In most studies, tDCS did not significantly reduce depression or anxiety scores as the studied patients did not have elevated scores indicating depression and anxiety. In the few studies where the patients had scores indicating mild/moderate dysfunction, tDCS was more effective. The risk of bias in the included studies was assessed as moderate. Despite the null or near-null results, tDCS may still prove to be an effective treatment option for depression and anxiety in MS, because tDCS produces a neurobiological effect on the brain and nervous system. To facilitate further work, several possible mechanisms of action of tDCS have been reported, such as the modulation of the frontal-midline theta, reductions in neuroinflammation, the modulation of the HPA axis, and cerebral blood flow regulation. Conclusions: Although tDCS did not overall demonstrate positive effects in reducing depression and anxiety in the studied MS patients, the role of tDCS in this area should not be underestimated. Evidence from other studies indicates the effectiveness of tDCS in reducing depression and anxiety, but the studies included in this review did not include patients with sufficient depression or anxiety. Future studies are needed to confirm the effectiveness of tDCS in neuropsychiatric dysfunctions in MS.

Intracardiac Echocardiography-Guided Atrial Flow Regulator Implantation for HeartFailure.

Intracardiac Echocardiography-Guided Atrial Flow Regulator Implantation for HeartFailure.

Structured triage in the emergency department via intelligent assistant service OPTINOFA : Results of amulticenter, cluster-randomized and controlled interventional study in Germany

In Germany, asubstantial reform of emergency care is strictly recommended. Regulation of patient flows into the ambulatory and stationary sectors remains amajor issue.In the OPTINOFA project funded by Innovationsfunds, anew triage system was developed for astructured primary evaluation of both urgency and care level of emergency cases. OPTINOFA was evaluated in acluster-randomized, controlled multicenter trial using astepped-wedge design in eight emergency departments (ED) from 1July2019 to 31May2021. Additionally, data from one ED were used for comparison of temporal changes without intervention. The primary study endpoint represented the increase of patient transfers to the ambulatory sector; secondary endpoints included the outcome, process and quality indicators as well as mean emergency care costs.In the study, 46,558 emergency cases were included in the control period and 37,485 emergency cases in the intervention period. Concerning the primary endpoint, asignificant increase of transfers to the ambulatory sector were detected in the per-protocol EDs (p < 0.001, odds ratio = 10.59). Waiting times were significantly reduced by an average 20 min in the intervention phase. Furthermore, astable admission rate was found within 3days after initial ED presentation. Cost analysis revealed no increase of treatment expenses within 28 days after ED admission.In this project avalid assistant service for structured primary evaluation of urgency and care level was successfully developed for emergency cases and served as adigital triage instrument with interoperable format. Clinical trial results revealed great potential for the OPTINOFA triage system to control patient flows in emergency and acute medicine.

Collision detection and fault diagnosis with DMAO-GRU for flow regulating valve

Abstract Fault diagnosis and condition monitoring are critical to the real-time and accurate flow regulation of the flow regulating valve. For the blockage fault, one of the main types of flow control valve faults, this paper proposes a collision detection and fault diagnosis method based on gated recurrent unit (GRU) and dynamic model-based adaptive external torque observer (DMAO). Firstly, combined with the generalized momentum, the DMAO based on multi-layer perceptron (MLP) and system dynamic model is constructed. Compared with the dynamic model with fixed parameters, the estimation error is reduced by 25%. Secondly, this paper proposes a collision detection method based on DMAO-GRU. In the absence of an accurate dynamic model, the optimal performance of collision detection is achieved by parameter adaptive estimation and time series signal modeling technology, compared with other detection methods. Moreover, according to the estimation of DMAO and collision detection results, this paper proposes a method to detect the degree of valve port blockage and realizes condition monitoring and fault-tolerant control.&amp;#xD;

Experimental investigation into effects of material and energy regulation of debris flow by using check dams with different porosities

The design of check dam openings for debris flow control has been identified as a longstanding challenge, with no definitive solution yet identified. In this study, a quantitative analysis of the control efficacy of check dams with varying opening rates is presented. Field investigation data of 67 check dams located in Wenxian County, Gansu Province, were utilized to gain a preliminary understanding of their running state and damage situation. Building upon this, five check dams with opening rates ranging from 2.1% to 10.4% were designed and subjected to testing. Parameters including volumetric water content, pore water pressure, deposit morphology, and particle size distribution were analyzed to investigate the effect of varying opening rates on debris flow control. The results showed that: 1) As the opening rate of the check dams increased, the peaks of volumetric water content and pore water pressure behind the dam first decreased and then stabilized. When the opening rate was increased to 6.3% or higher, these parameters reached stable values. 2) Check dams with different opening rates all demonstrated good effects in retaining the coarse and sluicing the fine, resulting in the average particle size behind dams was coarsened by 2.65 times. This coarsening was primarily attributed to an increase in the proportion of retained particles within the 2–5 mm size range. 3) An optimal opening range of 4.2%–6.3% was identified for effective debris flow control. Compared with other dams, Dam II with opening rate 4.2% exhibited superior performance in mitigating flow energy and intercepting coarse particles, but it imposed stringent strength-related requirements.