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This paper presents an investigation of magnetohydrodynamics (MHD) Casson nanofluid flow along a stretchable surface through a permeable medium. The modeling of the physical phenomena is considered with impact of thermal radiation, heat generation, slip conditions and suction. Transformations of the governing set of mathematical equations for the physical model are carried out into nonlinear ordinary differential equations (ODEs) with appropriate similarity variables. The nonlinear ODE solutions are carried out using the optimal homotopy analysis technique (OHAM), and the findings are presented for determining the influences of the emerging important parameters. The results indicate that velocity field increases in respect of porosity parameter, Casson fluid parameter and magnetic parameter while it declines for enhancing velocity slip and suction parameters. The temperature profile shows rising behavior for heat source, Prandtl number, thermophoresis, radiation and Brownian motion parameters while it declines for enhancing thermal slip parameter. Moreover, the concentration profile enhances for rise in Brownian motion parameter while it reduces for Schmidt number and nanoparticle parameter. We also showed the accuracy of the present results by indicating that skin friction values for varied magnetic parameters agree with earlier findings in the literature. [ABSTRACT FROM AUTHOR]

This study examines the flow dynamics and heat transfer characteristics of Maxwell fluid in a channel influenced by magnetohydrodynamics (MHD), Joule heating, thermal radiation, and boundary layer suction/blowing effects. The governing partial differential equations (PDEs) for momentum, energy, and concentration are transformed into ordinary differential equations (ODEs) using similarity transformations. The boundary value problem (BVP) is solved numerically using the bvp4c solver in MATLAB, yielding accurate solutions for velocity, temperature, and concentration profiles under various parameters. Key findings reveal that the porous parameter decreases the velocity profile but increases the temperature profile for both suction and blowing effects. Additionally, the MHD, Deborah, and Eckert numbers significantly influence the velocity and temperature profiles differently under these conditions. This study highlights the crucial role of integrating MHD, thermal, and boundary control effects to optimize performance and efficiency in engineering systems involving Maxwell fluids, with applications in polymer processing, biomedical engineering, electronics cooling, oil recovery, and chemical processing. [ABSTRACT FROM AUTHOR]

Background: The bronchial suction has been applied in speeding lung collapse. Low suction pressure may not speed lung collapse, but high pressure causes occult lung injury. The aim of the study was to explore efficacy and safety of different suction pressure for speeding lung collapse. Methods: Eighty-four subjects undergoing uniport video-assisted thoracoscopic surgery (VATS) were randomly assigned for non-suction (Group 0), -10 cmH2O suction pressure (Group − 10), and − 30 cmH2O suction pressure (Group − 30). The primary outcome were the lung collapse scores (LCS) at 0 min (T0) after the visualization of the lung using a 10-point visual analogue scale and area under the curve (AUC) of LCS over time. The secondary outcomes included disconnection from the ventilator, the assessment of occult lung injury using NOS-3 expression, histologic scores of lung injury, and lung W/D weight ratio, intraoperative hypoxemia, the incidence of perioperative pulmonary complications. Results: Both the LCS at T0 and AUC analysis showed that compared with Group 0, Group − 10 and Group − 30 significantly achieved good lung collapse (P < 0.05), but no difference between Group − 10 and Group − 30. Four patients in Group 0 were treated with disconnection maneuver. The assessment of occult lung injury showed no differences. Conclusions: Applying − 10 cmH2O suction pressure for 1 min when pleural incision is a relatively safe method to promote lung collapse without the occurrence of occult lung injury. Trial registration: Chinese Clinical Trial Registry number, ChiCTR2200062991. Registered on 26/08/2022. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the stone clearance rate and limitations of a novel integrated suction capability within a single-use flexible ureteroscope according to stone particle size. Methods: Varying sized stone particles were created using a stone phantom (Begostone Plus, Bego ©, Lincoln, RI, USA). Particle size ranged as follows: 63–125 µm, 125–250 µm, 250–500 µm, 500 µm- 1 mm and 1–2 mm. These were mixed with Normal saline (0.9%) to mimic in vivo conditions. The suction enabled single-use flexible ureteroscope (Pusen, Zhuhai, China) was used to aspirate stone fragments in three trials. Firstly, aspiration of 5 g of each dust range was attempted. Secondly, a direct comparison of the integrated suction to a manual syringe technique was applied to 1 g of each size range. Finally, aspiration was applied to 5 g of a heterogenous 1:1:1:1:1 mixture. Endoscopic clearance rate (g/min) and number of blockages were recorded. Each challenge was repeated three times. Results: The integrated suction cleared 100% of dust < 250 µm. Endoscopic clearance rates were significantly faster than manual aspiration (3.01 g/min versus 0.41 g/min) for dust between 125 and 250 µm (p = 0.008). Complete endoscopic clearance by 180 s (without encountering test limiting blockages) was unsuccessful for particles > 250 µm. Clearance rates were greatly limited by stone particle size heterogeneity above 250 µm, to 0.09 g/min. Conclusion: This technology works better in vitro than previously DISS evaluated methods when challenged by stone dust < 250 µm. However, this adaptation is significantly challenged in the presence of stone dust particles > 250 µm. [ABSTRACT FROM AUTHOR]

The present study investigates hybrid nanofluid (HNF) behavior at the stagnation point near a stretching/shrinking sheet using the Tiwari and Das model. The governing equations were transformed into a boundary layer flow model and simulated using COMSOL Multiphysics 6.0. This research examines flow characteristics, temperature profiles, and distributions by varying parameters: stretching/shrinking (λ , −2 to 2), slip flow (δ , 0 to 1 m), suction (γ , 0 to 1), and similarity variables (η , 0 to 5). The HNF comprised equal ratios of copper and alumina with total concentrations ranging from 0.01 to 0.1. The results showed that velocity profiles increased with distance from the stagnation point, escalated in shrinking cases, and decayed in stretching cases. Increased suction consistently reduced velocity profiles. Temperature distribution was slightly slower in shrinking compared to stretching cases, with expansion along the sheet directly proportional to η estimates but controllable through suction adjustments. The findings were applied to enhance photovoltaic thermal (PV/T) system performance. Stretching sheets proved crucial for improving electricity production efficiency. Non-slip wall conditions and increased copper volume fractions in the presence of suction effects led to notable improvements in electrical efficiency. The maximum average efficiency was achieved when γ = 0.4, λ = 2, δ = 0.7, and ϕ 2 = 0.01, which was of about 10%. The present numerical work also aligned well with the experimental results when evaluating the thermal efficiency of conventional fluids. These insights contribute to optimizing PV/T system parameters and advancing solar energy conversion technology, with potential implications for broader applications in the field. [ABSTRACT FROM AUTHOR]

The matric suction in unsaturated soil depends on the type of soil and various flux conditions i.e., infiltration, evaporation and no flow. The shear strength of unsaturated soil changes with change in matric suction leading to varying resistance of soil under various flow conditions. In this study, the bearing capacity of strip foundations resting over unsaturated clay considering variation of matric suction with depth for different surface flux conditions and position of water table, has been obtained using finite element lower bound limit analysis. Modified Mohr-Coulomb yield criteria based on unified effective stress approach has been employed to incorporate the contribution of matric suction stress to the failure condition. A non-dimensional bearing capacity factor was introduced to estimate the bearing capacity of strip foundations and presented as a function of different influencing parameters such as foundation width, water table depth, soil properties, various flow conditions and their flow rate, and surcharge pressure. The influence of variation of unit weight of soil in the unsaturated zone, air entry and pore size distribution parameters, residual degree of saturation of soil, specific gravity of soil solids, and foundation-soil interface roughness on the bearing capacity has also been examined and found to be insignificant. [ABSTRACT FROM AUTHOR]

Within the cutting-edge realm of Geotechnical Biology, the interplay between soil mechanics and biological systems has unveiled profound insights that align with the rural sustainability, forestry and agroecosystems. This inquiry, encompassing the role of soil characteristics and parameters in shaping plant behavior and root growth, creating a suction effect that draws water towards them and underscores the intricate relationships that govern soil-plant interactions. A numerical simulation was expertly dissected using Plaxis 2D software, particularly focused on understanding the complex behavior of root water uptake over time and the changing level of groundwater and its dynamics rhythm affected by the evolution of plants. The output results in our study have important implications for understanding the soil-plant system and the role of geotechnical processes in biological analyses. Our findings suggest that the stability and behavior of geotechnical systems can have a significant impact on plant growth and distribution, underscoring the importance of considering geotechnical processes in biological analyses. [ABSTRACT FROM AUTHOR]

This paper describes a simple methodology to calculate the two-dimensional seepage across an infinite unsaturated slope using models of one-dimensional infiltration through horizontal ground. The methodology decomposes the seepage across the infinite slope into antisymmetric and symmetric parts, whose respective solutions are combined to calculate the actual flow regime. The antisymmetric solution is trivial and does not even require integration of the governing continuity equation, while the symmetric solution, albeit non-trivial, reduces to the case of one-dimensional flow through horizontal ground, for which solutions already exist. The methodology is generally applicable to the calculation of distinct seepage regimes across unsaturated slopes with different hydraulic properties under both stationary and transient conditions. The paper also defines the gradient of the piezometric head parallel to the slope, which is the Neumann boundary condition to be imposed on slope sections perpendicular to the ground surface. The rigorous definition of this gradient overcomes the need of imposing arbitrary boundary conditions in finite-element models. Finally, the paper demonstrates that all infiltrated water crosses the slope along the shortest path – namely, the path normal to the surface – while the flow parallel to the slope is entirely fed by an upstream source at infinite distance. [ABSTRACT FROM AUTHOR]

Vertical plate anchors are placed in the soil to improve the lateral resistance of various geotechnical structures. Extensive research has been conducted to find out the pullout capacity of vertical anchors in saturated or dry soil. Despite all these attempts, no research is available to study the behavior of anchors in unsaturated soil where the shearing resistance of soil is governed by the matric suction depending on the surface flow conditions and water table positions. Since the soil in field is mostly in unsaturated state; thus, the pullout resistance of vertical plate anchor has been aimed to be evaluated in this study. Finite element limit analysis solutions in terms of a non-dimensional pullout factor have been presented to find the pullout capacity of vertical anchors. The solutions are inclusive of the effect of soil properties, embedment depth, height of anchor plate, depth of water table from the ground surface, flow conditions and flow rate under an immediate breakaway condition. The effect of variation of other factors like the degree of saturation, unit weight of soil, van-Genuchten SWRC parameters, specific gravity of soil solids, and anchor-soil interface conditions has also been evaluated. [ABSTRACT FROM AUTHOR]

Background: Autologous bone dust can be filled in bone defects to promote effective bone healing but typically it is lost when using suction during surgery. The aim of this study was to develop a novel bone collector that can be used to collect bone chips/dust of varying sizes without changing current surgical procedures. Research design and methods: This collector was designed to connect to a surgical continuous suction system and comprised a plate filter with a 3 mm hole and featured a taper filter with a mesh size of 0.27 mm for the separation and collection of both coarse and fine bone chips/dust. The bone collector was manufactured using nylon 3D printing and plastic injection with biocompatible materials. Results: The bone collector functional test revealed high bone chip collection efficiency (93%) with automatic size separation function. Low (3.42%) filtration errors showed that most of the water can be drained smoothly from the bone collector. In clinical usability testing, bone collectors can provide functions demonstrated in in vivo spinal fusion and femoral fracture surgeries with different bone grafting size requirements. Conclusions: The novel bone collector has been validated as a viable and effective surgical device, offering surgeons an additional option to enhance patient outcomes. [ABSTRACT FROM AUTHOR]

Abstract Background The bronchial suction has been applied in speeding lung collapse. Low suction pressure may not speed lung collapse, but high pressure causes occult lung injury. The aim of the study was to explore efficacy and safety of different suction pressure for speeding lung collapse. Methods Eighty-four subjects undergoing uniport video-assisted thoracoscopic surgery (VATS) were randomly assigned for non-suction (Group 0), -10 cmH2O suction pressure (Group − 10), and − 30 cmH2O suction pressure (Group − 30). The primary outcome were the lung collapse scores (LCS) at 0 min (T0) after the visualization of the lung using a 10-point visual analogue scale and area under the curve (AUC) of LCS over time. The secondary outcomes included disconnection from the ventilator, the assessment of occult lung injury using NOS-3 expression, histologic scores of lung injury, and lung W/D weight ratio, intraoperative hypoxemia, the incidence of perioperative pulmonary complications. Results Both the LCS at T0 and AUC analysis showed that compared with Group 0, Group − 10 and Group − 30 significantly achieved good lung collapse (P

This study is important for the fields of pharmaceutical nano-drug suspension, biomedical engineering, pressure surges and food processing systems. The slip condition is necessary for polishing internal cavities and artificial heart valves in a variety of manufactured objects, micro- or nano-channels, and applications. Low Reynolds number (Re → 0) and long wavelength (δ ≪ 1) considerations are used in the formulation of the mathematical model at low non-Newtonian parameter values, nonlinear boundary conditions and the governing nonlinear equation are analytically solved using the perturbation method. The graphs of frictional force, pressure rise, velocity, pressure gradient, and streamline graphs are done using Wolfram MATHEMATICA software. In this paper, we compared the results of the total slip condition with those of the first-order slip condition and the absence of any slip effects. It has been noticed that increasing the suction and injection parameters leads to a decrease the pressure rate with complete slip effects, partial slip effects and no slip effects. We show that an increase in the third grade fluid parameter Γ increases the magnitude of axial velocity. From a physical perspective, it shows the shear thinning characteristic, which causes a decrease in viscosity and an increase in fluid velocity. Frictional force behaves differently when compared to pressure rate. In other words, the pressure gradient acts as an obstacle to the peristalsis-driven flow. The objective of the study is to find the impact of the peristaltic flow phenomena and the impact of peristaltic on third-grade non-Newtonian fluid where the suction and injection are prevailing which is similar to the thing in biomechanical devices, like blood vessels, etc. there is a change of oxygen and carbon dioxide from the tissue layer to the fluid within the blood vessel. [ABSTRACT FROM AUTHOR]

Geosynthetic-reinforced soil (GRS) walls built on hillslopes are more increasingly incorporated with geo-composite side drain in order to prevent the side-seepage entering the fill. This study evaluates the long-term moisture, pore-water pressure, and shear modulus, of a 6.5 m-high geogrid-reinforced soil wall in western Thailand. Through extensive field monitoring and in-situ spectral analysis of surface wave (SASW) tests, conducted during the Years 2018–2019, as well as laboratory tests, several key findings emerge. Free-free resonant frequency (FFR) testing of non-reinforced samples reveals the role of soil wetting and drying history and hysteresis in the stiffness-moisture relationship. In-situ pore-water pressure was found to be highest below the road surface near the wall face, decreasing with depth due to underdrainage, with values ranging from −27 to 5 kPa. The intersection of the side drainage board with the underdrain bottom layer shows the highest water content. In-situ and laboratory-derived soil-water retention curve (SWRC) were found to differ at greater depths. In unsaturated conditions, the in-situ small strain modulus of GRS appeared insensitive to suction stress below 10 kPa but was slightly affected under positive pore-water pressure, with multiple linear regression modeling indicating a dependency of stiffness on depth and pore-water pressure. • Uncertainties persist regarding pore water pressure distribution in the fill when designing geosynthetic-reinforced soil walls. • This study evaluates the long-term moisture, pore-water pressure, and shear modulus, of a 6.5 m-high GRS wall with modular side drains. • Pore-water pressure was highest near the wall face just below the pavement, and diminished with depth due to underdrainage. • In-situ G₀ of GRS wall was insensitive to suction stress in unsaturated conditions but slightly affected once the soil became saturated. [ABSTRACT FROM AUTHOR]

Seepage and slope stability are important problems analyzed in geotechnical engineering. Conventionally, the analysis is performed in conditions where the soil is intact. However, near-surface soil is subjected to various conditions that lead to heterogeneity, for example, the presence of cracks in clay, relics in weathered rock, and plant roots. The presence of cracks and other forms of heterogeneity on the near-surface layer increases the rainfall infiltration into the slope and changes the pore water pressure distribution accordingly. Water infiltration increases the pore water pressure, raises groundwater level, and decreases the matrix suction of unsaturated soils - which is a critical factor for the stability of slopes. This study aims to evaluate the effect of varying permeability of near-surface soil on the rainwater infiltration to slope and, subsequently, the safety factor. In this case, the near-surface soil is modeled as a layer with higher permeability. Numerical analysis performed in this study using SEEP/W and SLOPE/W indicated that considering this condition results in a higher safety factor of the slope because the higher permeability resulting from heterogeneity helps dissipate pore water pressure, which is critical in maintaining the slope stability during heavy rainfall.

Changes in the chemistry of the pore fluid are known to have an impact on the hydro-mechanical behaviour of clays. Experimental evidence collected in recent decades has led to the formulation of constitutive chemo-mechanical models for expansive soils used in engineering practice for the containment of pollution, such as bentonite. Less attention has been paid to modelling the chemo-mechanical behaviour of non-expansive clays, which are less frequently used for geoenvironmental applications, but equally exposed to chemical changes. Key differences between the impact of salinity on the fabric of expansive and non-expansive clays are pointed out. At the macroscopic scale, an increase in salinity causes a translation of the normal compression line of non-expansive clays to higher void ratios, which in some cases is also accompanied by an increase in compressibility. The opposite occurs for expansive clays. Such experimental evidence provides the basis for a chemo-mechanical model formulated in the frame of elasto-plasticity with generalised hardening, whose yield surface expands with pore fluid concentration. The model is validated against experimental results, both original and from the literature. Simulation results compare very well with those of tests performed on reconstituted, compacted and intact samples. [ABSTRACT FROM AUTHOR]

Background: No in vitro surgical study has evaluated the time-dependent contamination of surgical suction tips compared with controls. Our purpose was to determine the difference in suction tip bacterial contamination rates between suction-positive and suction-negative tips. Materials and Methods: A matched-pair analysis of the contamination of surgical suction tips over a six-hour period was performed in two clean operating rooms. One suction tip was connected to standard wall suction (suction-positive group), with a matched control tip not connected to wall suction (suction-negative group). At time zero and then at hourly intervals for six hours, the distal 3 cm of suction tips were removed, placed in nutrient broth for 48 hours, then plate cultured. One hundred tips were collected for each time interval. Results: Eighty-two of 700 (11.7%) suction tips had bacterial contamination. Sixty-three (18.0%) of 350 suction-positive tips were contaminated, with 19 (5.4%) of the 350 suction-negative tips contaminated (χ2 = 26.7, p < 0.001). Suction tip contamination was time-dependent with the first significant difference between groups occurring after two hours of continuous suction (χ2 = 4.0, p = 0.04). Contamination rate in the suction-positive group increased significantly after one hour compared with time-zero controls (χ2 = 7.1, p = 0.008). There was no significant difference in frequency of positive cultures over time in the suction-negative group compared with time-zero controls. Conclusions: This is the first controlled laboratory study suggesting a time-dependent increase in positive suction tip cultures. From our data, operating room staff should have an awareness that suction tips represent a potential source of bacterial concentration. We recommend that when not in use, suction tip valves be closed if this feature is available, that hosing be manipulated to cease suction when not needed, that suckers be disconnected from tubing, or that suckers be exchanged at frequent intervals. Doing so may reduce bacterial contamination on the suction tip. [ABSTRACT FROM AUTHOR]

In this paper, by introducing a new yielding mechanism based on the widely acknowledged double-structure theory, the original UH model for unsaturated soils is extended to capture the behaviour of expansive clays. A novel expansion potential is further established to evaluate the effect of overconsolidation on the volume change of unsaturated expansive clays during wetting. With only one additional parameter, the proposed model can describe the behaviour of both wetting-collapse and wetting-induced swelling for unsaturated clays. Comparisons between model predictions and test results show a good agreement which verifies the capability of the proposed model in charactering the features of unsaturated expansive clays under various stress histories and stress paths. [ABSTRACT FROM AUTHOR]

The present investigation explores the transient magnetohydrodynamics gravity‐driven flow of a viscous, incompressible, electrically conducting fluid past a permeable exponentially accelerated vertical plate in the presence of thermal radiation and suction. Due to several applications in different areas, the influence of Hall current, Dufour number, heat source parameter, and chemically reactive species diffusion are vital and are incorporated in the study, which is the novelty of the present work. The model equations are derived and resolved by utilizing an analytical technique called the Laplace transform procedure. Various properties of the flow due to the influence of different vital parameters have been depicted with the help of graphs. The computed gradients of velocity, temperature and concentration are presented in tabular form. The Hall parameter is observed to strengthen the secondary flow while diminishing the primary flow. Dufour number and heat source parameter enhance the fluid temperature and velocity profiles while the heat sink declines them. Enhancement of the acceleration parameter significantly amplifies the primary skin friction coefficient. Suction boosts the heat transport as well as the mass transport rates at the surface of the plate, whereas injection declines them. Further, the Dufour number causes a significant reduction in the Nusselt number and magnitude of the secondary skin friction coefficient. The practical applications of the current research are the design of aircraft, cooling of microchips, Hall accelerators, separation of isotopes and many more. [ABSTRACT FROM AUTHOR]

The spread of COVID-19 through aerosols and droplets occurs during dental treatment. Dentists use highvolume suction (HVS) and saliva ejectors to suction saliva, blood, and water from the oral cavity. Since the pandemic, prototyping, production, and use of extraoral suction (EOS) have increased. EOS comprises HEPA (High-Efficiency Particulate Air), plasma ions, and ultraviolet (UV) filters. This study was used to see the effectiveness of the use of EOS through a comparison of physical and acceptability tests on the use of EOS at UGM Prof. Sodeomo Dental Hospital using three EOS brands, Coxo™, Eighteeth™ Vacstation, and Eostra™. Physical Test is used to assess the ability of a tool when used--Acceptability Test to assess user acceptance of EOS based on usage experience. The study was conducted at the UGM Prof. Soedomo Hospital (Professional Education Clinic, Resident Education Clinic, General Service Unit, and Specialistic Service Unit) in 2021 with 90 respondents who were EOS users. The EOS with the most incredible suction power, noise figure, and electrical power was Eostra™, while based on user experience, the EOS that was more accepted and more comfortable for users to use was Coxo™. EOS reduces aerosol exposure during dental treatment, and based on this study, EOS that had good capacity was not necessarily comfortable to use by users; this was because each brand had advantages and disadvantages, so the selection of EOS was adjusted to the capacity of the operator and the practice site. [ABSTRACT FROM AUTHOR]

Aims: Water-absorbing polymer (WAP) is recognized as a suitable soil additive for enhancing water retention and storage in the root zone under arid condition. The presence of such additives may alter the soil water characteristic curve (SWCC) and hence, may affect the plant growth. The effect of WAP on SWCC particularly, with the presence of vegetation is rarely explored. Therefore, this study investigates the combined influence of WAP and vegetation on SWCC for unraveling the soil-plant-WAP-atmosphere interaction. Methods: Two different WAPs along with vegetation species Solanum Lycopersicum species, were considered. The SWCCs along with its model parameters (Air entry value (AEV); Plant available water content (PAWC), FC (Field Capacity) and Permanent Wilting Point (PWP)) were established for silty loamy soil considering the different combinations of WAPs and vegetation. The changes in root structure were analysed with and without the presence of WAP. Results: Parameters such as FC, PWP and PAWC are increased by more than 1.5 times with the presence of WAP and vegetation compared to control soil This is mainly attributed to the alteration in pore volume in the soil matrix. Root-induced soil showed higher moisture retention than control soil at a specific suction which is affected by the root biomass/architecture. Conclusions: The study indicates that the WAP helps to reduce water demand during arid condition. This study also demonstrates the usefulness of SWCC as a tool to unravel the combined influence of WAP and vegetation on soil-water storage and water retention characteristics of soil associated with soil-WAP-root-atmosphere interaction. [ABSTRACT FROM AUTHOR]

Many available ground improvement techniques are effective, but involve large amounts of carbon dioxide emissions. Any green ground improvement technique would thus be beneficial. In this work, dry air, supplied at low pressure and relative humidity, was used to remove water from a soft soil deposit. The investigation was carried out at model scale, with a soft soil layer formed in a box of size 1.0 × 1.0 × 0.75 m. The soil bed was fitted with slender granular columns for the injection of dry air. The technique is the reverse process of vacuum consolidation, in which the magnitude of negative pore water pressure that can be applied to the soil is limited and thus requires careful construction procedures. The dry-air approach is simple and does not require any complex construction procedures. The investigations carried out over a limited period showed a significant improvement in the strength of the soil bed, indicating possible full-scale implementation. Full-scale implementation of the technique may not require any new construction methods as the procedure is very similar to that adopted in vacuum consolidation. However, variabilities in ground conditions, including the groundwater table, may pose additional challenges and supplementary information (soil–water characteristic data and numerical modelling) may be necessary to implement this technique at full scale. [ABSTRACT FROM AUTHOR]

The generation of the suction force between a rigid cylindrical frame constricting a submerged cavitating jet and a solid surface is considered. The separation force needed to overcome the suction effect is experimentally determined in a specially developed setup. The dependences of the suction force on the frame diameter and the distance from the nozzle cavitator are obtained using numerical modeling. The volume fraction of the vapor phase inside the frame and the static pressure along the suction surface are calculated. The mechanism of the appearance of the effect and the criteria of its vanishing are explained on the basis of the data obtained. [ABSTRACT FROM AUTHOR]

A comprehensive experimental program was performed in order to understand the mechanical behavior of model piles associated with water infiltration in collapsible loess. Real-time measurements were recorded for pile head settlement, pile shaft friction, and pile base resistance, as well as for the soil behavior, including soil settlement, volumetric water content, and soil suction. The experimental results suggest that both the pile head settlement and pile base resistance increased with water infiltration. The linear pile axial force distribution gradually changed to a "D" shape, with the maximum pile axial force occurring in the middle instead of the end stage of water infiltration. Such behavior can be attributed to a reduction in the contribution of soil suction, degradation of the pile–soil interface shear strength, and settlement of the collapsible soil. In addition, a softening model was proposed by modifying the traditional shear displacement method for interpretation of the mechanical behavior of piles in collapsible loess. There was good agreement between our experimental results and those from the literature and the results predicted using the proposed model, suggesting that the model can be used as a tool in the rational design of pile foundations in collapsible soils. [ABSTRACT FROM AUTHOR]

This paper proposes a generalized framework to estimate the seismic active earth thrust on rigid retaining walls with unsaturated backfill. A novel suction stress-dependent approach was developed to compute the horizontal and vertical seismic acceleration profiles within the backfill. The framework applies the limit equilibrium method with a log-spiral failure surface and considers the influence of suction-stress through the effective stress approach. A detailed validation of the proposed framework is conducted by comparing it with well-established solutions reported in previous studies showing a satisfactory agreement. Validation was performed for the cases of static loading with suction and seismic loading without suction because of the unavailability of the data for the combined case. The influence of suction on the seismic active earth thrust for different soil types and environmental conditions is presented together with other parameters including wall height, soil friction angle, frequency of input excitation, and horizontal and vertical seismic acceleration coefficients. [ABSTRACT FROM AUTHOR]

The emerging concept of hybrid nanofluids has grabbed the attention of researchers and scientists due to improved thermal performance because of their remarkable thermal conductivities. These fluids have enormous applications in engineering and industrial sectors. Therefore, the present research study examines thermal and mass transportation in hybrid nanofluid past an inclined linearly stretching sheet using the Maxwell fluid model. In the current problem, the hybrid nanofluid is engineered by suspending a mixture of aluminum oxide A l 2 O 3   and copper C u nanoparticles in ethylene glycol. The fluid flow is generated due to the linear stretching of the sheet and the sheet is kept inclined at the angle ζ = π / 6 embedded in porous medium. The current proposed model also includes the Lorentz force, solar radiation, heat generation, linear chemical reactions, and permeability of the plate effects. Here, in the current simulation, the cylindrical shape of the nanoparticles is considered, as this shape has proven to be excellent for the thermal performance of the nanomaterials. The governing equations transformed into ordinary differential equations are solved using MATLAB bvp4c solver. The velocity field declines with increasing magnetic field parameter, Maxwell fluid parameter, volume fractions of nanoparticles, and porosity parameter but increases with growing suction parameter. The temperature drops with increasing magnetic field force and suction parameter values but increases with increasing radiation parameter and volume fraction values. The concentration profile increases with increasing magnetic field parameters, porosity parameters, and volume fractions but reduces with increasing chemical reaction parameters and suction parameters. It has been noted that the purpose of the inclusion of thermal radiation is to augment the temperature that is serving the purpose in the current work. The addition of Lorentz force slows down the speed of the fluid and raises the boundary layer thickness, which is visible in the current study. It has been concluded that, when heat generation parameters increase, the temperature field increases correspondingly for both nanofluids and hybrid nanofluids. The increase in the volume fraction of the nanoparticles is used to enhance the thermal performance of the hybrid nanofluid, which is evident in the current results. The current results are validated by comparing them with published ones. [ABSTRACT FROM AUTHOR]

Bioconvection phenomena offer practical applications in biomicrosystems, fuel cells, biosensors, biocomputing, electronic thermal management, and renewable energy systems, showcasing their relevance and potential impact across various engineering sectors. Consequently, this study delves into the examination of a bi-dimensional magnetohydrodynamic nanofluid flow model encompassing the intricate dynamics of gyrotactic microorganisms, subject to the effects of suction and thermal radiation. The primary objective of the investigation is to optimize the thermal energy transfer efficiency of the fluid while concurrently minimizing associated costs, with the secondary aim of diminishing the frictional resistance at the fluid-solid interface. The basis for energy and momentum equations incorporating radiation using Rosseland’s approximation is established by the Buongiorno nanofluid model. The foundational PDEs along with their BCs, are reformulated into ODEs utilizing similarity variables, then transformed into a set of first-order ODEs ensuring compatibility with MATLAB’s bvp4c solver, which offers high convergence rates and accuracy due to its efficient algorithms and precision handling. Heat transfer rate boosts up by increasing suction and radiation parameters, while it dwindles due to an increase in the magnetic field. Enhancing suction and the magnetic field lowers skin friction. Microbial concentration surges by increasing the magnetic field, while suction minimizes it. Intensifying the thermophoresis parameter increases the concentration of nanoparticles. [ABSTRACT FROM AUTHOR]

This study investigates the steady, incompressible MHD flow of a hybrid nanofluid over a vertical solid cone embedded in a porous medium under suction effect. The research explores the effects of various factors, such as thermal radiation, chemical reactions, heat generation, viscous dissipation, and Joule heating on heat and mass transfer phenomena. To investigate the effects of hybrid nanoparticles, we consider single-walled carbon nanotubes (SWCNT) and alumina (Al2O3) along with water (H2O) as the base fluid. After a suitable similarity transformation, the governing equations are reconstructed and solved using the Keller-box numerical scheme. We present graphical and tabular analyses of various parameter impacts on heat transfer profiles and coefficients. This study provides valuable insights into the control of fluid dynamics and heat transfer in porous media, which have significant implications for industrial and engineering applications. The findings of the current article are in excellent agreement with previously published works. [ABSTRACT FROM AUTHOR]

The ureteral access sheath (UAS) has been a boon and a bane in flexible ureteroscopy (FURS), with its merits and demerits well established. Its design and dimensions were instrumental in reshaping the way flexible scopes were used and were key adjuncts to establishing retrograde intrarenal surgery (RIRS) as a standard of care in the endourological management of renal stones. With the ever-changing landscape of RIRS over the decades shaped by technological advancements in lasers and flexible scopes, the UAS has also continuously evolved. The utility of suction in endourology has recently changed the way RIRS is performed and is a game changer for FURS outcomes. With strong clinical and experimental evidence to support its use, the UAS has undergone a transformative change in the recent past, with its ability to monitor intrarenal pressure and provide a superior vacuum-cleaner effect that improves the trifecta of RIRS, namely an improved single-stage stone-free rate (SFR), minimise complications, and reduce reinterventions. Our comprehensive review outlines the key clinical and experimental evidence and traces the developments that were key to modifying the traditional UAS into a flexible and navigable suction ureteric access sheath (FANS) and highlights how the design and modifications, in turn, influence the ability to push the boundaries of RIRS. [ABSTRACT FROM AUTHOR]

Limited experimental and theoretical research has been conducted on the shear strength of unsaturated soils over a wide suction range. This study aimed to investigate the shear strength characteristics of a weakly expansive soil over a wide suction range (0.05–367 MPa) through a series of triaxial tests. The results of the experiments demonstrate that, under the same net confining stress, the shear strength increases with the suction over the entire suction range. Furthermore, an increase in suction leads to a change in the shape of the stress–strain curve, from strain-hardening to strain-softening. The effect of net confining stress on the stress–strain curve and volumetric strain-axial strain curve varies with suction. An additional analysis indicates that the cohesions and angles of internal friction acquired through net stress differ from those obtained through effective stress. The angles of internal friction at different suctions remain the same on the shear strength-net normal stress (τf−(σ−ua)) plane, while the cohesions increase exponentially with increasing suction. Based on these test results, a novel equation for the shear strength of unsaturated soil over a wide suction range is proposed by incorporating suction-dependent cohesion. The results of the study show excellent agreement between the predicted and measured shear strength results over a wide suction range, and its superior accuracy is demonstrated through comparisons with several existing models in the literature. [ABSTRACT FROM AUTHOR]

BACKGROUND: Open respiratory secretion suctioning with a catheter causes pain and tracheobronchial mucosal injury in intubated patients. The goal of mechanical insufflation-exsufflation (MI-E) is to move secretions proximally and noninvasively by generating a high peak expiratory air flow. Nebulized hypertonic saline with hyaluronic acid (HS-HA) may facilitate suctioning by hydration. We assessed the safety and tolerance of a single session of airway clearance with MI-E and HS-HA in critically ill intubated patients. METHODS: Adults with a cuffed artificial airway were randomized to (1) open suctioning, (2) open suctioning after HS-HA, (3) MI-E, or (4) MI-E with HS-HA. Adverse events, pain and sedation/agitation scores, and respiratory and hemodynamic variables were collected before, during, and 5-min and 60-min post intervention. RESULTS: One-hundred twenty subjects were enrolled and completed the study. Median (interquartile range [IQR]) Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 22 (16--28); median (IQR) age was 69.0 (57.0--75.7) y, and 90 (75%) were male. Baseline respiratory and hemodynamic variables were comparable. Adverse events occurred in 30 subjects (25%), with no between-group differences. Behavioral pain equivalents and Richmond Agitation-Sedation Scale were higher during suctioning in groups 1 (P < .001) and 2 (P < .001). Independent predictive variables for higher pain and agitation/sedation scores were study groups 1 and 2 and simultaneous analgosedation, respectively. Noradrenaline infusion rates were lower at 60 min in groups 2 and 4. PaO2/FIO2 had decreased at 5 min after open suctioning in group 1 and increased at 60 min in group 3. CONCLUSIONS: We observed no difference in adverse events. MI-E avoids pain and agitation. [ABSTRACT FROM AUTHOR]

Suction is a highly evolved biological adhesion strategy for soft-body organisms to achieve strong grasping on various objects. Biological suckers can adaptively attach to dry complex surfaces such as rocks and shells, which are extremely challenging for current artificial suction cups. Although the adaptive suction of biological suckers is believed to be the result of their soft body's mechanical deformation, some studies imply that in-sucker mucus secretion may be another critical factor in helping attach to complex surfaces, thanks to its high viscosity. Inspired by the combined action of biological suckers' soft bodies and mucus secretion, we propose a multiscale suction mechanism which successfully achieves strong adaptive suction on dry complex surfaces which are both highly curved and rough, such as a stone. The proposed multiscale suction mechanism is an organic combination of mechanical conformation and regulated water seal. Multilayer soft materials first generate a rough mechanical conformation to the substrate, reducing leaking apertures to micrometres (~10 μm). The remaining micron-sized apertures are then sealed by regulated water secretion from an artificial fluidic system based on the physical model, thereby the suction cup achieves long suction longevity on complex surfaces but minimal overflow. We discuss its physical principles and demonstrate its practical application as a robotic gripper on a wide range of complex dry surfaces. We believe the presented multiscale adaptive suction mechanism is a powerful unique adaptive suction strategy which may be instrumental in the development of versatile soft adhesion. [ABSTRACT FROM AUTHOR]

A triple‐microstructure hydro‐mechanical constitutive damage model was proposed to describe the hydro‐mechanical behaviour of MX80 bentonite pellet/powder mixture, based on the results from a series of suction‐controlled oedometer tests and microstructure observations. Emphasis was put on the pellet damage behaviour. The model parameters were determined essentially based on these results. The model response was firstly verified with the obtained oedometer tests. Then, the results of Molinero‐Guerra et al. and Darde who carried out suction‐controlled oedometer tests and swelling pressure tests on similar bentonite pellet/powder mixture were employed to validate the proposed model. It appeared that the global volume behaviour and the development of swelling pressure with suction of the bentonite mixture could be well reproduced. The model allowed gaining insights into the microstructural evolutions under oedometer loading. The global compression behaviour was governed by the filling of inter‐grain pores at unsaturated state, but by the compression of grains themselves at saturated state. Conversely, when wetted under constant‐volume condition, inter‐grain pores and intra‐grain macro‐pores were closed, by the swelling of intra‐grain micro‐pores. Examination of the water‐retention property showed that water saturated the intra‐grain micro‐pores at suction 19 MPa, and then started filling intra‐grain macro‐pores. When inter‐grain pores and intra‐grain macro‐pores were all closed at suction 0.1 MPa, water finally came back to intra‐grain micro‐pores. On the whole, the hydro‐mechanical behaviour of the bentonite pellet/powder mixture can be well described by the proposed model. [ABSTRACT FROM AUTHOR]

Nanofluids help in many fields to improve the performance of thermal systems by augmenting heat transfer rates through their thermophysical properties. The performance of the nanofluids with various base fluids may be different. Therefore, the study and comparison of behaviors of various nanofluids are useful in several applications such as fuel as a coolant in automobiles, and in medical and electronic equipment to reduce the thermal resistance. This research proposed a novel model to investigate the flow behavior of three different nanofluids over an elongating surface in the presence of a non-uniform heat source and thermal radiation effects. This investigation describes how the considered nanofluids behave in the presence of a transverse magnetic field, and other effects. The proposed governing boundary layer partial differential equations (PDEs) are reformed into a system of nonlinear ordinary differential equations (ODEs) by introducing the proper similarity transformation. The finalized equations are solved numerically with the help of the ND solve package in Mathematica software. We intended how the fluid flow and heat transfer are affected by non-dimensional controlling factors with the help of graphics. Further, the calculations and discussions are accompanied by the numerical values of the skin friction coefficient and heat and mass transfer rates. According to the current findings, the Maxwell nanofluid exhibits superior performance in velocity, and the Oldroyd-B nanofluid shows more concentration and less temperature. As a special case, the results of this investigation are compared with the existing results, and found a good agreement between the results. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of fine content and matric suction on the behavior of silty sand soil through both net and effective stress variables in the critical state soil mechanics framework. For this purpose, a set of CD triaxial tests in saturated and unsaturated states were performed on the samples of sand with different fine contents. The results showed that in term of net stress variables the position of the critical state line (CSL) in stress space for a given non-plastic fine depend on suction. However, these lines approach each other by choosing a proper effective stress relationship. The CSLs in the coordinates of the void ratio in the term of effective stress changed as a function of the non-plastic fine content and matric suction. However, using the concept of the equivalent intergranular void ratio and considering a special mean effective stress variable depending on suction, the CSLs were converged so that a single line can be defined to describe the behavior of the silty sand at the critical state. Finally, the stress-dilatancy relationship of two constitutive models was examined and it was shown that the use of the equivalent state parameter could facilitate the use of these relationships. [ABSTRACT FROM AUTHOR]

The volume change behaviour of an unsaturated compacted loess under thermo-hydro-mechanical loads is comprehensively investigated in this experimental research. A new temperature/suction-controlled triaxial apparatus with triple cells was developed. Temperature- and suction-controlled isotropic tests, heating–cooling tests with isotropic net stress and suction control and drying–wetting tests with isotropic net stress and temperature control were conducted on an unsaturated compacted loess from Shaanxi, China. Experimental results show that compressibility indices remain unchanged at various temperatures, but show different variation trends with changes in suction. Both suction hardening and thermal softening were observed. Irreversible volumetric contraction is induced in the compacted loess upon heating–cooling path and becomes more significant at higher isotropic net stresses and higher suctions. Lower over-consolidation ratio prior to heating results in greater irreversible contraction in loess samples. Water-holding capacity of loess samples decreases upon heating, but it is independent of the stress level. The hydraulic hysteresis of samples has no significant change with temperature changes. Slight shrinkage occurs during drying process in loess samples, and collapse can be observed in wetting process. Heating has limited effect on the drying shrinkage of loess samples but induces more distinctive wetting collapse. [ABSTRACT FROM AUTHOR]

The results of the swept wing boundary layer stability investigation are presented for the case, when the wing surface has a region of gas suction through the wall normal to the surface, while the wing is in Mach number 2 flow. In the flow regime considered the predominant boundary layer instability type is the crossflow instability. The gas suction effect on the development of unstable modes in the boundary layer is investigated using the linear stability theory and direct numerical modeling. The numerical modeling of laminar (undisturbed) flow fields with regions of gas suction and disturbed flow fields is carried out by integrating Navier–Stokes equations. An analysis within the framework of the linear stability theory is performed using the -method. The suction region location is varied with conservation of the integral intensity. It is shown that the mode instability growth can be considerably suppressed at the expense of an optimal disposition of the suction region. [ABSTRACT FROM AUTHOR]

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The study provides novel and valuable insights into the behavior of fluid flow and heat transfer in a generated plume under the influence of an aligned magnetic field, which is a complex and less-explored area in fluid dynamics. Incorporating variable viscosity and suction effects adds to the realism and applicability of the model, as it accounts for more realistic conditions where fluid properties change with temperature and external forces influence the flow. A mathematical model is formulated as a system of coupled partial differential equations to analyze the flow dynamics. Subsequently, a numerical solution is derived with stream function formulation for the system of coupled partial differential equations, which transmuted it into ordinary differential equations. To achieve this, the numerical properties of the problem are established through the utilization of a Shooting method in tandem with the MATLAB tool bvp4c. The graphical representations of both missing and specified boundary conditions, analyzes the influences of the viscosity parameter ε, suction parameter ξ, magnetic force parameter S, Prandtl number Pr and magnetic Prandtl number γ. The impact of these parameters on the heat transfer and fluid flow is given in detail. Inclusion of suction velocity counteracted the effects of temperature-dependent viscosity. The velocity f′, current density ϕ″, temperature θ, skin friction f″ and magnetic flux ϕ′ depicted an enhanced behavior while heat transfer rate θ′ dropped with an increment in viscosity parameter ε. However, for an increasing suction parameter ξ, the reverse trend of these properties is observed as compared to the viscosity parameter ε. The inclusion of suction counteracted to the effects of variable viscosity. Understanding how heat plumes behave under magnetic fields the study aims to provide insights that can be applied to real-world scenarios, such as improving cooling systems in industrial applications, enhancing environmental safety measures, and optimizing biomedical engineering processes.

Summary: Background: Retrograde intrarenal surgery (RIRS) is the main treatments for upper urinary tract stones. The Ureteral Access Sheath (UAS) serves as a supplementary tool, facilitating direct kidney access during RIRS. High quality of evidence comparing tip bendable suction ureteral access sheath (S-UAS) with traditional UAS in RIRS for the treatment of renal and ureteral stones is lacking. The purpose of the study is to compare the efficacy and safety of S-UAS with traditional UAS in RIRS for the treatment of renal or ureteral stones ≤30 mm. Methods: An international, multicenter, and superiority randomized controlled trial included 320 intention-to-treat patients across 8 medical centers in China, the Philippines, Malaysia and Turkey from August 2023 to February 2024. The inclusion criteria were patients ≥18 years old with renal or ureteral stones ≤30 mm. RIRS was performed using either S-UAS or traditional UAS. The primary outcome was the immediately stone-free rate (SFR). Secondary outcomes included SFR 3 months after operation, operating time, hospital stay, auxiliary procedures, complications (using the Clavien–Dindo grading system), and improvement in the Quality of Life (QoL) score. Differences between proportions [risk difference (RD)]/means [mean difference (MD)] and 95% confidence intervals (CI) were presented. This study is registered at ClinicalTrials.gov: NCT05952635. Findings: The S-UAS group demonstrated a significantly higher immediately SFR (81.3% versus 49.4%; RD 31.9%; 95% CI 22.5%–41.7%; p = 0.004) compared to the traditional UAS group, as determined by the one-side superiority test. Additionally, the S-UAS group exhibited a higher SFR at 3 months post-operation (87.5% versus 70.0%; RD 17.5%; 95% CI 8.7%–26.3%; p