Bridge Force Research Articles

Mathematical study on gravity effect of the liquid bridge between two rigid spheres

To better understand how gravity affects the evolution of capillary force and meniscus shape of the vertical liquid bridge between two millimeter-size spheres, an explicit mathematical model was built using Surface Evolver software. In this study, the rupture behavior of liquid bridge in the equilibrium state was studied using the energy minimization method, and the validity of the mathematical method followed was verified by comparing with existing research results. In addition, the gravity effect on the meniscus shape and geometric parameters were systematically studied. Finally, the gravity effect on the residual liquid volume after the liquid bridge ruptures was examined, and a calculation method for the residual liquid volume on the sphere was proposed, which was proven by mathematical methods and experiments. The relative error was <16% when the liquid dripping error was neglected, proving the feasibility of the calculation method.

Analysis on Influence of Tensioning of Reserved Steel Bundles on Internal Force and Deformation of Continuous Rigid Frame Bridge

Analysis on Influence of Tensioning of Reserved Steel Bundles on Internal Force and Deformation of Continuous Rigid Frame Bridge

Study on mode I interlaminar fracture toughness of laminated plates considering interface angle

Multidirectional laminates are more widely used in practical engineering, and their fiber bridging characteristics are more obvious than unidirectional laminates. Due to the deficiency of research on the relationship between interface angle and interlaminar fracture toughness of multidirectional laminates, the numerical model of interface mode I fracture toughness of multidirectional laminates related to interface angle is modified by analyzing the difference between steady-state fracture toughness and initial fracture toughness of each interface. Meanwhile, the mode I interlaminar fracture toughness of multidirectional composite laminates under five interface modes is studied. Based on the finite element software, the cohesion model is established and verified. The analytical results are in good agreement with the experimental data, and the modified model can better verify the relationship between interface angle and interlaminar fracture toughness. At the same time, the fiber bridge force in the process of delamination along different interfaces is calculated, which provides a basis for the modified model.

Effect of pH on the sorption of dissolved organic carbon derived from six tree species in forest soils

Dissolved organic carbon (DOC) is an important component of the total carbon (C) pool in temperate forest soils. The ability of forest soils to sorb DOC is an essential feature in the context of ecosystem changes (such as climate change) and the resulting changes in the C cycle. The aim of this study was to investigate the ability of forest soils with different pH levels to sorb DOC from litter of different forest tree species. To accomplish this, we conducted two laboratory experiments in which the soil differed in the depth from which they were sampled (topsoil vs. subsoil) and the initial DOC content. We modified the soil pH to obtain a range covering most soils in temperate forests (approximately 3.5–8). Soil samples were leached with extracts of similar DOC content obtained from the litter of six main forest-forming tree species in temperate zone. Increased DOC sorption was observed at approximate soil pH levels of 3.5 and 7.5, with the highest sorption capacity occurring at low pH. The DOC sorption capacity was decreasing with consecutive leaching with litter extract. The capacity of DOC sorption also depended on the litter species. In addition, the initial concentration of C in soil had no significant relationship with sorption capacity. Litter species were related to the sorption of released DOC, which was probably linked to the Al content in the litter. The increased DOC sorption at low pH was likely because of dissolved organic matter protonation (saturation of functional groups with H+ ions resulting in proton bridging and van der Waals forces), while Ca2+ ions causing cation bridging, flocculation or non-columbic interactions were likely responsible for the increased sorption at high pH. Our research shed light on the significant effects of soil pH on the stabilization of DOC, as well as the important role and positive influence of Al on DOC sorption by forest soils. Our findings provide new, significant insight by presenting that litter-derived DOC sorption is dependent both on soil pH and litter chemical composition.

Effects of particle roughness on the rheology and structure of capillary suspensions

We show that particle roughness leads to changes in the number, shape and resulting capillary force of liquid bridges in capillary suspensions. We created fluorescently labeled, raspberry-like particles with varying roughness by electrostatically adsorbing silica nanoparticles with sizes between 40 nm and 250 nm on silica microparticles. Rougher particles require more liquid to fill the surface asperities before they form pendular bridges, resulting in smaller and weaker bridges. In a system where the effective bridge volume is adjusted, higher particle roughness leads to less clustered networks, which show a higher yield strain for a matching storage modulus compared to the smooth particle networks. This finding suggests that the particle-particle frictional contacts also affects the strength of capillary suspensions. Using asymptotically nonlinear oscillatory rheology, we corroborate the non-cubical power law scaling of the third harmonic in the shear stress response that results from both Hertzian contacts and friction between particles connected by capillary bridges. We demonstrate that the repulsive Hertzian contact parameter A is sensitive to the liquid bridge strength and that roughness appears to shift the relative scaling of the power law exponents from adhesive-controlled friction to load-controlled friction.

Geometric similarity on interparticle force evaluation for scaled-up DEM particles

The scaled-up particle model, which is also commonly known as the coarse grain model or discrete parcel model, is frequently used to reduce the computational cost in Discrete Element Method (DEM). In the direct force scaling approach, the forces acting on original particles are first estimated and then directly scaled to apply to scaled-up particles. It is therefore crucial to appropriately evaluate the variables of the original particles, e.g. overlap and separation distance, from the scaled-up particles particularly when estimating complex interparticle forces. The present work proposes the use of geometric similarity for the evaluation of the original particle overlap and separation distance. It is demonstrated that the proposed method can provide an almost identical stress-strain curve between the original and scaled-up particles during uniaxial compression of a packed particle bed, whilst the conventional method in the literature gives significant overestimation of the stress. In addition, the scaled-up particles can reasonably replicate the original velocity distributions of cohesive particles with both liquid bridge and JKR surface adhesion forces in a dynamic flow system (vertical mixer). The simulation results suggest that the method proposed can be applied to any type of interparticle forces. A scaling of time step limit is also derived theoretically and discussed.

Investigation of agglomerating and wetting behaviour during coal dust suppression via the synergistic application of hydrocarbon and short-chain-fluorocarbon surfactants in the presence of electrolytes

This paper investigated the agglomerating and wetting behaviour during coal dust suppression via the synergistic application of hydrocarbon and short-chain-fluorocarbon surfactants in the presence of electrolytes. A maximum 51.01% and 53.12% reduction in surface tension is achieved after compounding FS-50 and FS-3100 with SDBS and FMEE. Short-chain fluorocarbon surfactants reduced the immersing time of coal particles from maximum 637.03 s to minimum 28.06 s, and further diminished to 9.33 s in the presence of electrolytes. The addition of short-chain fluorocarbon and electrolytes can significantly promote the agglomeration behaviour among treated coal particles. After the addition of NaCl and NaAc, the maximum dust suppression rate reaches 95.12%, which is 1.21–1.33 times of binary surfactants and 1.59–2.01 times of the solely application of hydrocarbon ones. The agglomerating behaviour is more sufficient in predicting the dust suppression rate. The larger the coal particles, the higher liquid bridge force and stronger agglomerated coal particle clusters.

Influence of printing parameters on 3D printing engineered cementitious composites (3DP-ECC)

3D printing of engineered cementitious composites (3DP-ECC) serves as an effective means to enable digital and automated construction while removing the dependence of steel reinforcement typical in normal concrete construction. As generally recognized, process control in 3DP is as crucial as material constituents to the performance of the printed structure. Printing parameters pose direct influence on the micro-structure of material, which further impacts the macro-scale properties of printed ECC. In this paper, the effects of different nozzle standoff distances and nozzle travelling speeds are investigated. It is found that lowering the nozzle standoff distance within a certain range increases the in-plane tensile strength and strain capacity of 3DP-ECC by 39% and 30%, respectively. The tensile performance is also enhanced by a moderate printing speed. In addition, a 141% increase in interfacial fiber bridging force is found with elevated nozzle standoff distance. Furthermore, the micro-structure observed via μ-CT correlates well with the printing parameters, micro-structure and macro-scale properties of 3DP-ECC.

Experimental Study on Fluidization Behaviors of Wet Rice Threshed Materials with Hot Airflow

Among food crops, rice has the largest planting area, the highest yield per unit area and the largest total yield in China. However, cleaning performance is reduced by the high moisture content of rice during the harvesting process. In order to decrease the adhesion among wet rice threshed mixtures and improve the cleaning performance, the method of hot airflow cleaning was proposed. Firstly, the fluidization characteristics of wet sticky rice under the action of hot air were compared with those of dry particles. In this work, the minimum suspension velocity and the fastest suspension time were used and quantified to characterize the fluidization characteristics. It was found that the minimum suspension velocity and the fastest suspension time of the wet rice threshed mixture are both higher than those of dry particles due to the liquid bridge force. Moreover, the dispersion degree of the wet rice threshed mixture can be improved by the hot airflow due to the decrease in the surface water content of impurities. Secondly, the influence of the temperature and vibration frequency in the air-and-screen cleaning device on the dispersion characteristics of the wet rice threshed mixture were investigated. The accumulation mass was measured to quantify the dispersion degree. It was found that the increase in vibration frequency has little effect on the dispersion of the wet rice threshed mixture. The accumulation mass on the front of the sieve decreases slightly with the increase in the gas temperature range from ambient temperature to 30 °C. Then, the dispersion degree increases rapidly when the temperature exceeds 40 °C. The dispersion effect is the best when the temperature is 50 °C and the vibration frequency is 5 Hz. These results provide a basis for the cleaning of the wet rice threshed mixture in a combine harvester.

Wet Adhesion of Soap Bubble Bridge between Two Curved Surfaces

Wet adhesion phenomenon of the soap bubble bridge is widespread in the climbing behaviors of geckos and insects, and the surface shapes generally have important impact on the adhesion behavior of soap bubble bridge. In order to focus on the effect of the shape on the wet adhesion, we study the adhesion behavior between two rigid surfaces containing different shapes such as concave, flat, and convex. For a given soap bubble bridge, the relationship between adhesion force and separation is numerically calculated, and the corresponding configuration of soap bubble bridge is also given. The results show that the adhesion force of soap bubble bridge decreases with the increase of separation. This trend is the same as the case of liquid bridge, although the volume of liquid bridge is constant while the volume of soap bubble bridge varies. The adhesion force with concave rigid surfaces is bigger than that of the other two kinds of rigid surfaces at the same separation. The wetting radius of the soap bubble bridge decreases with the increase of separation. The appearance of this phenomenon results from the equation of state for the gas in the soap bubble bridge. This research may improve the understanding of the mechanical mechanism of wet adhesion.

CFD–DEM simulation of wet granular-fluid flows and heat transfer in an integral multi-jet spout-fluidized bed

The hydrodynamic and heat transfer characteristics of dry and wet particles in quasi-two-dimensional integral multi-jet spout-fluidized bed (IMJSFB) and conventional spouted bed (CSB) were numerically studied using Computational Fluid Dynamics-Discrete Element Method (CFD-DEM), where the effect of wet content of particles is realized by introducing the liquid bridge force. In addition, the agglomeration, particle mixing, circulation, collision and heat transfer of IMJSFB and CSB under different moisture content were quantitatively studied. It is found that with the increase of gas velocity, the circulation capacity of particles in both spouted beds increases first and then decreases, and particle circulation characteristics of IMJSFB are obviously better than those of CSB. The appropriate moisture content of particles is beneficial to enhance the heat transfer effect, and compared with CSB, IMJSSFB has more obvious advantages in dealing with wet particles. This study has important significance for the mixing and heat transfer of class D wet particles, which is less studied in fluidization technology, and provides theoretical and technical reference for the actual design and operation of spouted bed.

Controlling particle adhesion of synthetic and sewage sludge ashes in high temperature combustion using metal oxide nanoparticles

During combustion, ash particles can adhere to the internal walls of the plant due to partial melting and generate a liquid bridge force at the high operating temperatures. The adhered ashes inhibit energy recovery and stable operation of the plant. To achieve highly efficient energy recovery during combustion, it is necessary to investigate suitable methods to control adhesiveness according to each operational case. Herein, the ability of small amount (1–3 wt%) of nanoparticles (NPs: SiO2 NPs, Al2O3 NPs, and Fe3O4 NPs) as additives to control the adhesiveness at high temperatures was investigated. The controllability of each type of NP with respect to the adhesiveness of various synthetic ashes, which served as model compounds, was evaluated to clarify the role played by the different NPs. To demonstrate the practical utility of the NPs as additives, ash samples derived from the incineration of sewage sludge were investigated. Given the chemical complexity of the ash systems, it was discovered that a chemical effect and an increase in the porosity of the powder bed can effectively decrease the adhesiveness of ash particles produced at high temperatures.

The network structure of depressive symptomatology in Peruvian adults with arterial hypertension.

Background: Globally, arterial hypertension (AH) has increased by 90% over the last four decades, and has increased by 1.6% in Peru over the previous four years. Scientific evidence indicates the prevalence of depressive symptoms in patients with AH and its importance in the comprehensive evaluation of the adult for adherence to clinical treatment. Previous studies carried out in the Peruvian population with AH mostly report the prevalence and associations, but do not indicate which depressive symptoms are more relevant in patients with AH. This study involved a network analysis of depressive symptomatology in Peruvian patients with AH using network estimation. Network analysis is used in this study for analysis, control, and monitoring purposes. Method: A representative cross-sectional study at the national level, using secondary data from 2019 Demographic and Family Health Survey (ENDES) was performed. The sample used included men and women of age over 17 years diagnosed with AH and was able to respond to Patient Health Questionnaire-9 (PHQ-9). Results: The symptoms of depressive mood (bridging force and centrality) and energy fatigue or loss (bridge centrality) play an essential role in the network structure, as does the feeling of uselessness in terms of closeness and intermediation. Conclusion: The study highlighted the symptoms related to depressive mood and energy fatigue or loss as bridging symptoms, which could trigger a depressive episode in patients diagnosed with AH. The results will contribute to developing personalized treatments aimed at patients with specific depressive symptoms who have also been diagnosed with AH. The study analysis presents statistical coefficients of effect size (≤ 0,1 = small; > 0,1 to < 0,5 = moderate; ≥ 0,5 = large) to determine network connections.

Liquid component effect on the dispersion and explosion characteristics of solid-liquid mixed fuel

The adhesion of liquid fuel is an important factor hindering the disengagement of solid fuel particles. And the liquid component characteristics of mixed fuel also have a significant impact on the final combustion and explosion reaction result. The liquid bridge force was detected by a self-assembled device. And the influence of the liquid fuel on the dispersion and explosion characteristics of solid–liquid fuel (nitromethane-diethyl ether-aluminum) was investigated by a laser particle size analyzer and a 20 L explosion vessel. The liquid bridge force result from the liquid fuel decreases with decreasing surface tension and liquid fuel volume effectively reduce the hindering of liquid adhesion on dispersion. And the increase in spray pressure also alleviate fuel agglomeration. The smaller the fuel particle size, the higher the explosive overpressure and the (dp/dt) max. Effectively coping with the impact of the liquid fuel adhesion on fuel dispersion could significantly accelerate the fuel reaction rate and promote energy transfer.

Influence of Air Solubility on the Flotation Performance of Low-Rank Coal.

Low-rank coal (LRC) contains large amounts of harmful impurities that must be processed before utilization. Flotation is an effective means for separating fine particles, which can be influenced by air solubility in water. In this work, deaerated water (DW), ordinary water (OW), and pressurized water (PW) were prepared to research the underlying mechanism of the effect of air solubility on the flotation performance of LRC. The results show that PW dissolves the greatest amount of air in the three kinds of water (DW, OW, and PW). The flotation performance of LRC in different water types is directly proportional to air solubility in aqueous solutions. In addition, the induction time of LRC in PW (600 ms) is significantly shorter than those in OW (1200 ms) and DW (4000 ms). Atomic force microscopy (AFM) studies reveal that typical interfacial nanobubbles (NBs) only form on a highly oriented pyrolytic graphite (HOPG) surface in PW due to the supersaturated air in water. Furthermore, the interaction between LRC particles and HOPG in PW is significantly stronger than those in both OW and DW, which is attributed to the capillary force of rgw nanobubble bridge formed between particles. The hydrophobic interaction enhanced by NBs is critically important for the attachment of LRC particles to macrobubbles in flotation. Overall, air solubility in water has a great effect on LRC flotation performance, and PW flotation technology can be extended to LRC purification.

Liquid bridges between particles and the hydrophobic or hydrophilic surfaces of solar photovoltaic glass

Photovoltaic (PV) power generation technology is one of the most important methods for reaching the carbon peak and achieving carbon neutralization. Dust accumulation on the surface of PV glass greatly reduces the working performance and power generation efficiency of PVs. The hydrophobic or hydrophilic surfaces on the PV glass have substantial self-cleaning potential. In this study, the liquid bridges formed between particles and the hydrophobic or hydrophilic surfaces of solar PV glass are investigated. The effects of the liquid bridge force and the influencing factors for these two surfaces on particle dynamics behaviours are studied. Furthermore, the self-cleaning abilities of these two surfaces are also discussed. The results indicate that the liquid bridges formed between a particle and a hydrophilic PV glass placed horizontally or obliquely exhibit similar saddle shapes, but the liquid bridges wrap the particle on the surface of hydrophobic PV glass. The influence of the liquid bridges causes particles to adhere to the tilted hydrophilic or hydrophobic surfaces at liquid bridge volumes (VL) < 6 μL, making initially moving particles stay on these two tilted surfaces with 6 μL ≤ VL ≤ 20 μL and even achieving self-cleaning properties at VL > 20 μL. Both hydrophobic and hydrophilic surfaces increase the self-cleaning forces resulting from the liquid bridge formation with increasing VL, thus completing the self-cleaning process. Increasing the self-cleaning forces and decreasing the friction force and the liquid bridge force improves the self-cleaning abilities of the surface. These research findings have important theoretical significance and commercial engineering value in preventing and reducing dust accumulation on glass.

Optimization of Suspender Cable Force of Long-Span Concrete Arch Bridges Based on Embedded Matrix Method

In order to simplify the completion process of cable force optimization and adjustment in long-span concrete-filled steel tube arch bridges, a new method was proposed in the present study. To this end, a reasonable completion cable force calculation method was proposed based on the influence matrix principle of cable force optimization. Then combined with the mechanical characteristics of concrete-filled steel tube arch bridge, the weighted matrix was introduced to simplify the influence matrix of cable force and optimize the suspender cable force. The performed comparative study showed that the maximum difference of single cable force between the measured and calculated values is less than 5%, and the calculation error satisfies the requirements of the specification. It is concluded that the proposed method can accurately control the suspender tension construction in the arch bridge, optimize the cable force of long-span concrete filled-steel tube arch bridge, and realize the comparison and selection of various optimization schemes. The research results have been successfully applied to the suspender force adjustment of Third Pingnan Bridge, which greatly simplifies the adjustment steps and the total cable force difference in the whole bridge is 1.37%, the difference between the measured and designed suspender tensions of Heshan Hongshui River Bridge at completion state is less than 2%. The successful application of this method effectively saves the labor and material cost of suspender adjustment and further enhances the superiority of steel tube concrete arch bridge. The proposed method is expected to be an excellent choice to monitor constructions, adjust the bridge completion stage, and provide a reference for the suspender tension construction control of similar bridges.

Influence mechanism of liquid bridge evaporation on the dynamic behaviour of dust particles on solar photovoltaic panels

Solar photovoltaics (PVs) are one of the most promising renewable energy sources to solve the global environmental and energy crises. Dust agglomeration on PV panels greatly affects their operation life and power generation efficiency. In this study, the evaporation mechanism and laws of liquid bridges as well as the evaporation time and interaction forces for liquid bridges and particles are investigated. The effects of liquid bridge evaporation and its influencing factors on dust dynamic behaviour are discussed. Liquid bridge evaporation in the muddy state with small particle spacing can cause particle agglomeration on PV panels. However, it is very difficult for the capillary, the ribbon, and the pendulum states or the muddy state with large particle spacing to affect particle motion. In the muddy state, the interaction force for a small particle spacing consists of not only the liquid bridge force but also the drag force caused by liquid bridge evaporation, and that for a large particle spacing consists of only the drag force; in the other three states, the interaction force consists of only the liquid bridge force. Liquid bridge evaporation can greatly intensify particle agglomeration and even scaling processes with decreasing particle size. These findings can provide important theoretical guidance and value for engineering improvements in power generation and safe operation of PV panels.

Influence of H2O and SO3 on fine particles coagulation for sintering flue gas after desulfurization in an alternating electric field.

Electric coagulation of fine particles has been studied in the simulated sintering flue gas after semi-dry desulfurization to quantify the influence of H2O and SO3. The electric coagulation platform has a DC charging zone and an AC coagulation zone. Fine particles were divided into different diameter intervals to deeply explore the impact of H2O and SO3, including less than 0.15μm (PM0.15), 0.15-0.5μm (PM0.15-0.5) and 0.5-1μm (PM0.5-1). The particle charge, mass fractions of fine particles, and the mean diameter are measured and compared under water and SO3 atmosphere. The experiments showed that the increasing AC voltage helps particles larger than 0.5μm to coagulate but has little effect on the rest particles without H2O or SO3. Both H2O and SO3 enhance the PM1.0 AC coagulation. When flue gas relative humidity went up from 20 to 80%, the charge per particle maximally increased by 120%, as well as the mass fraction of PM0.5-1, PM0.15-0.5, and PM0.15 decreased by 83.2%, 64.5%, and 66.6%, respectively. When the SO3 concentration rose up from 0ppm to 12.3ppm, the charge per particle maximally increased by 100%, as well as the mass fractions of PM0.5-1, PM0.15-0.5, and PM0.15 decreased by 54.5%, 28.6%, and 33.3%, respectively. The impact of water and sulfuric mist on the particle intervals was sequenced as: PM0.5-1 > PM0.15 > PM0.15-0.5. The influence on PM1.0 AC coagulation was sequenced as H2O > sulfuric mist > AC voltage. Through data regression, H2O had approximate linear correlation with the particle mass fractions while the impact of sulfuric mist was non-linear. The interparticle forces were calculated to analyze the dominant force of particle AC coagulation with water: liquid bridge force > Coulomb force > > van der Waals force. The liquid bridge force indicated that liquid film was form on the surface of fine particles when water or sulfuric mist was added into the system which was the main reason enhancing the AC coagulation.

A Bibliometric Study of the Pediatric Inguinal Hernia Publication Landscape from the Web of Science Database.

The number of times a research work gets cited by another article is one of the article-level metrics for assessing the quality of a research publication. Citation analysis by bibliometric review has been performed in several disciplines. The current study was aimed to systematically review the literature available on pediatric inguinal hernia since 1960 in terms of the 25 most cited articles in this field and analyze the bibliometric variables author and organizational collaborative patterns. Thomson Reuters Web of Science citation indexing database and research platform were used to retrieve the most cited articles in pediatric inguinal hernia (PIH) using appropriate search strings. The characteristics (name of authors, the total number of authors, the title of publication, journal of publication, year of publication, etc.) of the 25 top-cited articles were recorded. Specific bibliographical parameters were derived and analyzed. Visualization maps were generated using VOSviewer software. The analysis revealed that the Journal of Pediatric Surgery was leading the choice of journal for publication. While most of the publications originated from the United States of America, Schier was the most influential author. Five of the eight top-productive authors are also the most connected. Articles on laparoscopic repair in PIH have been heavily cited. Following the United States of America, Turkey stands out as the topmost productive country in PIH. The publications on PIH show that "collaboration" is the bridging force between productivity and influence on the academic community.