Resistance Force Research Articles

THEORY OF UNIFORM RISE/FALL OF A PHYSICAL BODY IN A MOVING MEDIUM

Well production collection and preparation systems play an important role in the separation of oil, gas and water. Proper control of the parameters of gas separators and settling tanks is a key task for their efficient operation. In this paper, the determination of the performance of separators and settling tanks is considered, and special attention is paid to the boundary conditions for maximum efficiency of the separation process. At the moment, the calculation of the performance of gas separators and various settling tanks is carried out according to formulas derived in the twentieth century, and the scientific world does not question their reliability or the reliability of their conclusion. And in order to either prove the reliability of these calculations, or to refute them, an analysis of work was carried out to determine the performance of separators and settling tanks. At the beginning of the work there is a description of how productivity is calculated in the modern world. After that, a discussion is held about the reliability of these calculations, where in the course of reasoning, logical arguments are given about the erroneous conclusions of past calculations. So it was found out that the main assumption in the previous calculations was the use of the absolute velocity of the body in determining the resistance force of the medium, while it was necessary to use the relative velocity of the body, namely the velocity of the body relative to the medium. The following are the new boundary conditions, the solution of this problem, and the conclusions obtained.But the most interesting are the further discussions in the work, during which answers to the questions are given: how and at what speed will the oil particle move in the gas environment of the gas separator at different ratios of forces acting on the particle. Thus, it was concluded that the relative velocity of a body floating freely in a liquid or gaseous medium always tends to a certain constant value, which is numerically equal to the critical velocity of the medium, that is, such a speed at which a particle of oil would be stationary relative to the earth with a moving medium. In this case, the absolute velocity of the body (particles of oil, water, gas) will be equal to the vector difference between the velocity of the medium and the critical velocity of the medium. Combining the obtained conclusions, a new theory about the motion of bodies in a moving medium is created.

The effect of salbutamol sulphate inhalation (an anti-asthmatic medication) on the surfaces of orthodontic Archwires.

This study aimed to compare the surface roughness and friction of different orthodontic archwires after exposure to salbutamol sulphate inhalation, an anti-asthmatic medication. Orthodontic archwires (stainless-steel [StSt], nickel-titanium [NiTi], beta-titanium [β-Ti], and copper-NiTi [Cu-NiTi]) were equally divided into two groups. The exposed groups were subjected to 20 mg salbutamol sulphate for 21 days and kept in artificial saliva. The control groups were only kept in artificial saliva. Surface changes were visualized using scanning electron microscopy (SEM). The average surface roughness (Ra) was evaluated using atomic force microscopy (AFM), and friction resistance forces were assessed using a universal testing machine. Statistical analyses were performed using t-tests and ANOVA followed by post hoc tests. Salbutamol sulphate did not change the surface roughness of StSt and NiTi archwires (p > .05). However, the change in the surfaces of β-Ti and Cu-NiTi archwires was significant (p < .001). The frictional forces of exposed StSt, NiTi, and Cu-NiTi archwires did not change (p > .05). However, the frictional forces of β-Ti archwires increased significantly after exposure to salbutamol sulphate (p = .021). Brushing with fluoride after exposure to salbutamol sulphate increased the frictional forces of β-Ti only (p = .002). Salbutamol sulphate inhalation significantly affected the surface texture of β-Ti and Cu-NiTi orthodontic archwires and increased the friction of β-Ti archwires. These deteriorating effects were not detected on the surface of StSt and NiTi archwires. Therefore, we suggest that β-Ti and copper titanium archwires should be used cautiously in individuals under salbutamol sulphate inhalation treatment.

Mathematical Modeling of a Screw Electromechanical Energy Converter Hydrodynamic Processes under Variable Load Conditions

This paper examines a multifunctional energy converter (MFEC), which is an induction motor with a solid (ferromagnetic) hollow rotor of external design. The functional purpose of the MFEC is the mixing and heating of loose or low-melting materials that move along the outer surface of the solid rotor. At the same time, the rotor is heated due to eddy currents excited by the inner stator winding. When calculating the dynamic modes of the MFEC - start-up, rotation at a constant speed, braking - it is necessary to know the magnitude of the moment of resistance to the rotation of the rotor. For the MFEC, which mixes the material in a closed limited space, this moment is not constant, but is determined by the viscosity of the medium; the diameter of the mixing channel; the amount of material captured in the mixing process; speed of rotation of the rotor, etc. In order to take into account main factors that are affecting on the moment of resistance, it is necessary to make a mathematical model of the behavior of the device in a fluid or viscous medium. This model will make it possible to find the functional dependence of the moment of resistance on all the above factors and to calculate the power spent on overcoming the resistance forces of the environment. In further calculations, modeling or design of the MFEC, this power will be part of the total capacity of the MFEC. This paper will be useful not only for the specific application under consideration, but also for any other processes related to the dynamic loading of electric motors.

Evaluation of strengthening efficiency based on combined global and sectional response of masonry arch bridges

The paper is focused on the numerical analysis of the efficiency of strengthening solutions dedicated to masonry arch bridges. An overview of common strengthening methods is described covering the most frequent techniques and their influence on the bridge’s structural behaviour. The numerical study concentrates on the longitudinal behaviour of the arch of single-span bridges. The applied methods are related to the addition of specific structural components on both sides of the arch – extrados and intrados. Two basic solutions are studied based on a rigid or flexible layer corresponding to the most common techniques being applied to these bridges around the world. A comparison of the selected strengthening techniques is given considering their impact on the bridge’s structural behaviour under incremental static loadings. Structural details of the solutions are given as well as their efficiency is evaluated through analytical and numerical analyses. Advanced nonlinear Finite Element models using a meso-modelling technique are presented and selected results showing the mechanical performance of the structure before and after strengthening are provided. The interpretation of the bridge model response parameters, representing the increment of resistance given by the addition of each reinforcement solution, is based on the analysis of the evolution of the structural failure modes up to the maximum load capacity of the bridges, namely in terms of the interaction of internal resistant forces M-N in representative arch cross-sections determined also analytically. Conclusions are formulated to identify optimal reinforcement solutions through the ratios of the maximum load capacity of strengthened and unstrengthened bridge cases, and the ratios between the areas of the M-N interaction diagrams of strengthened and unstrengthened solutions.

Numerical solution for the laterally loaded rigid piles considering resisting force and moment under combined loadings

A numerical method is first proposed for the response of laterally loaded rigid piles under lateral load based on the curved strain wedge model. The influence of shear displacement of the pile, resistance bending moment caused by the uneven vertical shear stress on the pile side and resistance force and bending moment at the pile bottom are all considered. The effect of the vertical load on the lateral response of the monopile foundation is then analyzed according to the practical fact that the piles are always subjected to combined loads. The vertical friction force on the pile side is derived by combining vertical load and horizontal bending of the pile, and the resistance force at the pile bottom is determined by both vertical load and pile self–weight. The effect of P–Δ on the pile foundation caused by the vertical load is also considered. Several field tests are used to verify the reasonableness and accuracy of the proposed method. The influencing factors are studied. The results show that the vertical load has a favorable effect on the lateral response of the pile in frictional soil and almost no effect on the lateral response of the pile in frictionless soil.

Effect of sinusoidal pressure gradient on MHD flow of viscoelastic fluid in a channel

Unsteady Hydro Magnetic oscillatory flow of incompressible viscoelastic fluid in a channel packed with porous material is investigated under the influence of oscillatory pressure gradient. Moreover, the applied magnetic field of moderate strength interacts with electrically conducting fluid, to generate a resistive volumetric body force. In addition to it, viscoelastic fluidity, characterizing the non-Newtonian behavior in conjunction with permeability of the medium as well as sinusoidal sheared flow due to imposed favorable pressure gradient, contribute to the novelty of the study. The previous work was confined to constant motion of the lower plate but the present work includes the sinusoidal motion of the lower plate in addition to the constant motion. The importance lies with the fact that the coupling effect of sinusoidal fluctuation and viscoelastic fluidity go hard in industrial applications, particularly in process industry. The governing equations characterizing the flow are solved analytically. The striking results of this study are: the formation of inverted boundary layer in case of oscillatory lower plate with moderately escalated time span but such instability leading to flow reversal, does not appear in case of constant motion of the lower plate. Hence, it is recommended that for stability of flow and to avoid flow reversal, higher frequency of oscillation as well as larger time span is not desirable. The elastico-viscosity property reduces the volume flow rate which may be useful to control the efflux and differentiates the state of motion (resulting low skin friction) and state of rest (resulting high skin friction) in respect shearing effects at the bounding surfaces.

Testing flax fibers using high-speed bending

The article presents a method of measuring bending rigidity of flax fiber during high-speed bending. This method is an important part of the effort to reduce the dependency on imported cotton. Unlike the standardized testing methods, the suggested approach closer imitates the conditions present during fiber processing and exploitation of fiber products. For evaluation of bending rigidity of flax fiber during high-speed bending there was used the scheme of loading (meeting the factors of Eule – Bernoulli theory) of a sample fixed in a cantilevered way with the following determination of the work done by bending and deformation by interaction with impact pendulum. The value of sample deformation was determined on the basis of the control of moments of the time of angle velocities deformation which took place by operating movement (during the tests) and free movement of the pendulum. The specific feature of determining the time of deformation were more precise calculations: of angle velocity of the pendulum considering the force of resistance to its free movement; of pendulum motion periods at different stages of its movement during its interaction with the sample; of the time of starting and finishing the interaction by sample bending using the method of dichotomy by approximation of angle velocity values; of angle velocity variation at different stages of its movement during its interaction with the sample. These more precise calculations has become the basis of generalized algorithm for determining the bending deformation by interaction with impact pendulum, done by electronic calculator. A hardware-software complex has been created that employs this algorithm to measure and visualize both sample deformation and pendulum energy loss, as well as angular velocity of the pendulum. A comparison of different kinds of natural bast fibers has been performed – specifically, flax, nettle and hemp. The bending rigidity of these samples has been determined to be 1.42, 2.53 and 6.45 newton‧mm2 accordingly. These differences match the well-known properties of those materials.

Aerial withdrawal: An atmospheric reading of Monika Maron's Flugasche

AbstractIn Monika Maron's Flugasche (1981)—the first novel from the GDR to deal with environmental issues—the poisoned atmosphere in the city of B. functions as an affective centre, around which emotions, actions and reactions of the main protagonist as well as of the other characters revolve. The journalist Josefa Nadler falls into the sphere of the environmental catastrophe and is overwhelmed by the atmospheric power of this meaningful situation. The corporeal experience of being exposed to subtle environmental violence, which has devastating consequences for the city of B. and debilitating effects on its inhabitants, evokes feelings such as fear, anger, shame and compassion. Moreover, it develops into a driving force for thoughts, decisions, commitment and resistance against the unfair air distribution, accompanied by a sense of powerlessness. The aim of the article is a re‐reading of the novel with a central focus on the largely non‐representational, affective and meteorological elemental spacetimes, which can not only be felt or bodily experienced but also designed or engineered in order to produce a certain time‐bound structure of feeling, for example, an oppressive climate of fear.

Applicability of Drag Equation on a Dimpled Golf Ball using Changing Wind Velocities

The drag equation is commonly used to relate the resistance force experienced by an object traveling through fluids with its velocity. The pattern might vary based on the specific geometry of the objects (e.g., a dimpled golf ball). The dimples are known to reduce the amount of drag during the ball’s flight through a series of complex aerodynamic processes. To investigate the ball’s drag pattern, pressure and air velocity on the golf ball, a CFD using Ansys fluent is performed to simulate its aerodynamic features under nine different wind velocities. After the experiment, it was found that the relationship between the drag and velocity of the dimpled golf ball still generally conforms to the drag equation. The pressure and velocity distributions are consistent with the hypothesis, while the aerodynamic details are presented. The effect of dimples is also visualized, contributing to the flow demonstration. The investigation is valuable because the aerodynamic process of the dimpled sphere structure in changing wind velocities is well presented and analyzed, and it inspires further explorations on the aerodynamic effects of the dimple geometry.

A Pneumatic Particle-Blocking Variable-Stiffness Actuator.

In order to improve the stiffness of flexible robots, this paper proposes a variable-stiffness elastic actuator. The actuator integrates the working principles of a pneumatic drive, wedge structure, and particle blockage. The anti-tensile stiffness of the actuator is nonlinearly negatively correlated with the air pressure because of the structural and material properties. The anti-compressive stiffness and lateral stiffness increase nonlinearly as air pressure increases, being 3 and 121 times greater at 0.17 MPa compared to 0 MPa, respectively. Beyond 0.17 MPa, the two stiffnesses of the actuator experience incremental growth due to wedge resistance forces.

Comparison of different blade shapes of translatory moving soil tillage tools

BACKGROUND: The efficiency and energy capacity of translatory moving soil tillage tools are largely determined by the parameters of their blades. If the parameters do not match the specified operating conditions, clogging the working tools with plant residues becomes possible, and a less energy-consuming type of soil cutting — sliding — may be replaced with a more energy-consuming type — chopping cutting. In this regard, it is very important for scientists engaged in improving the designs of translatory moving soil tillage tools to have a method for assessing the shape of the blades.&#x0D; AIMS: Development of a method for comparative assessment of various blade shapes of translatory moving soil tillage tools.&#x0D; METHODS: For this study, the fundamentals of agricultural mechanics, higher mathematics, and theoretical mechanics were used. The objects of the study were the blades of various soil tillage tools, providing with sliding cutting of soil. The study was conducted at the Gorsky State Agrarian University in the period from 2022 to 2023. The calculations results were compared with the materials of the corresponding standards.&#x0D; RESULTS: The method that helps to determine the relative values and directions of the resultant force of soil cutting resistance with a translatory moving blade of a soil tillage tool having a diverse shape has been developed. An example of the application of the method for assessment the effectiveness of blades of a garden tool, the cutting part of which is described by the equation of a straight line, a circle, an Archimedes spiral, a logarithmic spiral, as well as an example of assessment of a curved blade for soil tillage tools of cultivators are given.&#x0D; CONCLUSIONS: The proposed method for assessing the influence of the shape of a translatory moving flat blade of the soil tillage tools on the value of soil cutting resistance forces is easy to use and can be the basis for further development in order to analyze the effectiveness of the knives’ blade shape performing a plane-parallel movement.

PropelWalker: A Leg-Based Wearable System With Propeller-Based Force Feedback for Walking in Fluids in VR.

There has been an increasing focus on haptic interfaces for virtual reality (VR), to support a high-quality touch experience. However, it is still challenging to haptically simulate the real-world walking experience in different fluid mediums. To tackle this problem, we present PropelWalker, a pair of calf-worn haptic devices for simulating the buoyancy and the resistant force when the human's lower limbs are interacting with different fluids and materials in VR. By using four ducted fans, two installed on each calf, the system can control the strength and the direction of the airflow in real time to provide different levels of force. Our technical evaluation shows that PropelWalker can generate vertical forces up to 27N in two directions (i.e., upward and downward) within 0.85 seconds. Furthermore, the system can stably maintain the generated force with minor turbulence. We further conducted three user-perception studies to understand the capability of PropelWalker to generate distinguishable force stimuli. First, we conducted the just-noticeable-difference (JND) experiments to investigate the threshold of the human perception of on-leg air-flow force feedback. Our second perception study showed that users could distinguish four PropelWalker-generated force levels for simulating different walking mediums (i.e., dry ground, water, mud, and sand), with an average accuracy of 94.2%. Lastly, our VR user study showed that PropelWalker could significantly improve the users' sense of presence in VR.

Analysis of Stator-Slot and Pole-Pair Combinations in a Two-Degree-of-Freedom Split-Stator Induction Machine Based on Motion Coupling Model

2-degree-of-freedom split-stator induction machine (2DoFSSIM) exhibits high integration and material utilization for 2DoF motions, but the attractive topologies are difficult to determine due to exciting two different magnetic fields and two-directional motions. This paper investigates the helical motion coupling effect of rotary and linear motion parts, then the influence of stator-slot and pole-pair combinations on three motion characteristics is analyzed. Based on the proposed motion coupling model, the resistant torque and force production mechanism is revealed. It can be concluded that the output torque, force, and helical motion coupling effect are dominantly determined by the magnetic loading and pole-pair number of two motion parts. However, there is a tradeoff in choosing the pole-pair number to get the 2DoFSSIMs with high output performances and low helical motion coupling effect. Then, the stator-slot and pole-pair combinations selection method is proposed, and the topologies with attractive performances are chosen at different geometric diameters. Finally, the finite element analysis and experimental results are given to validate the proposed technique. <list list-type="simple" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <list-item> 2-degree-of-freedom split-stator induction machine, motion coupling model, helical motion. </list-item> </list>

Integrated Assessment of Discrepancy Between Tracheal Tube and Tube Exchanger as Advancement: A Manikin Simulation Study.

Advancing a tracheal tube over a tracheal tube exchanger into the trachea frequently causes difficulties because of the tube impingement on laryngeal structures. In the present study, we measured the resistance of tube advancement both objectively and subjectively with a variety of combinations of tube exchanger sizes and tracheal tubes using a manikin simulator. Lubricated 7.5 mm ID standard and Parker Flex-Tip (PFT) tracheal tubes were railroaded over the tube exchangers (OD 1-6 mm) into the trachea through the oral route in a manikin. Consequently, 12 combinations of tracheal tube-exchanger tube assemblies were evaluated. Tube advancing resistance at the laryngeal inlet was subjectively evaluated. The objective tube advancing resistance (force) at the laryngeal inlet was evaluated using a digital force gauge. The execution of each tracheal tube-exchanger trial was conducted 10 times. With a 1-mm tube exchanger, all intubation attempts with both standard and PFT tubes failed. Esophageal intubation or severe impingement at the right arytenoid accompanied with a bent tracheal tube was observed. With a 2-mm tube exchanger, during intubation with a standard tracheal tube, rotation of the tube was sometimes required; however, all other intubations were done without problems. When PFT tubes were used, all intubation attempts were performed without problems. The rest of the trials were successfully performed regardless of the combinations of tube exchangers and tracheal tubes; however, one attempt of intubation with a combination of a 5 mm tube exchanger and a standard tracheal tube required withdrawal and rotation of the tube because of impingement at the epiglottis. In cases where there was no gap resistance, which means tube advancing resistance generated by a gap between an introducer and a tracheal tube, the pressing force was approximately less than 10 N. However, in the cases requiring some interventions to overcome the gap, the pressing force reached around 15 N. When intubation failed, for example when the tube bent, or esophageal intubation, the pressing force reached around 30 N. Impingement due to the gap between the tube exchanger and the tracheal tube is thought to occur in the PFT tube less frequently. Once an impingement occurs, we can feel approximately twice the amount of resistance as usual, which may be a chance to consider taking some interventions. When the impingement is not released, regardless of interventions, excessive force may result in esophageal intubation or tracheal injury.

Experimental investigation of relationship between bearing capacity and vibration parameters for planetary exploration legged rovers

In recent years, robots with leg mechanisms have received considerable attention as high-running planetary exploration rovers. Rovers undertaking planetary exploration require outstanding running performance to travel on loose ground on which they mostly slip and hardly move forward. The movement of the rover easily deforms the surface of loose ground. This problem can be solved by increasing the bearing capacity. The bearing capacity, the resistance force exerted on the rover legs when they make contact with the ground, needs to be sufficiently large to prevent legged rovers from slipping on loose ground. The bearing capacity can be increased by compaction of the ground by imparting vibrations. This study investigates the relationship between the bearing capacity in the horizontal direction and vibration parameters because this relationship offers valuable information for improving the running performance of legged rovers. First, we investigated the effect of changing the vibration parameters on the bearing capacity. Our experimental results show that the bearing capacity is related to vibration acceleration. These results suggest that the bearing capacity can be estimated from the vibration acceleration. Next, the frequency and amplitude were compared as vibration parameters to devise an efficient method for increasing the bearing capacity. The results of these experiments showed that high-amplitude vibrations increase the bearing capacity to a greater extent than high-frequency vibrations. The reason is that high-amplitude vibrations generate larger additional vibrations by the collision between the rod and the ground than high-frequency vibrations. This knowledge is valuable for selecting a suitable vibration that can efficiently increase the bearing capacity. This study suggests a method of facilitating further planetary exploration using legged rovers.

Fire research of joint between special-shaped CFST column and U-shaped composite beam

The steel-concrete composite joint plays an important role in the building structure of transmitting load and maintaining structural stability, and the research on fire performance of composite joints is significant. The special-shaped concrete-filled steel tube (SCFST) column and U-shaped steel-concrete composite beam (USCB) have good fire resistance which is proved by authors' previous fire tests. Therefore, the fire performance of the joint between SCFST column and USCB, the temperature distribution, failure mode, fire resistance, and internal force distribution of the joint under fire are investigated based on the fire tests results of column and beam component. The results showed that the temperature of the joint zone is lower than that of the non-joint zone, which ensured that the strength and stiffness of the joint zone are higher than that of the non-joint zone (beam and column). Then the two failure modes including beam failure and column failure occurred in the composite joint in fire conditions. Furthermore, the internal force analysis indicated that internal force redistribution happens during the elevated temperature. The parameter analysis expressed that fire resistance decreases with the increase of load ratio and the beam-column moment ratio and increases with the increase of the beam-column stiffness ratio and the fire protection layer thickness. Finally, the high-temperature calculation formula for the bearing capacity of beam-column joint was proposed.

Trunk orthosis with joints providing resistive force improves dynamic sagittal alignment in postoperative patients with lumbar spinal stenosis

This study aimed to determine whether a trunk orthosis with joints providing resistive force (TORF) modifies sagittal malalignment during level walking in patients with lumbar spinal stenosis (LSS). Fifteen patients, 6 months after undergoing surgery for LSS, performed level walking at a self-selected speed while wearing a TORF. Dynamic sagittal alignment, including sagittal vertical axis, lumbar lordosis, and pelvic tilt, and spatiotemporal data as well as lower limb kinematic and kinetic data were recorded using a three-dimensional motion analysis system and six force plates. Statistical analysis was performed to compare these data with and without the TORF, respectively. Compared to the condition without the TORF, the use of the TORF significantly decreased positive sagittal vertical axis (p < 0.05) and increased the lumbar lordosis and pelvic tilt (p < 0.05). Peak hip flexion angle and extension moment during loading response (LR) significantly increased (p < 0.05), and peak hip extension angle and flexion moment during PS statistically decreased (p < 0.05). There was no difference in spatiotemporal data between the two conditions. Our findings suggest that TORF may modify the dynamic sagittal global alignment and lower limb kinematic and kinetics in postoperative LSS patients during level walking.

Surrogate-assisted investigation on influence of epistemic uncertainties on running safety of high-speed trains on bridges

The operational safety of high-speed trains traversing ballasted bridges is contingent upon the prevention of the ballast destabilization, which can interrupt load transfer from the rail to the bridge. Current design regulations indirectly address this limit-state by specifying a threshold value for the vertical acceleration of the superstructure. This value represents the condition at which the inertial forces induced by train passage exceed the resistive forces. However, this approach is based on limited experimental data and the influence of numerous parameters remains unexplored. As a result, reliability analyses pertaining to running safety are hampered by a lack of knowledge, leading to greater epistemic uncertainties. In this study, the impact of such uncertainties on this dynamic system is investigated using surrogate-based Imprecise Structural Reliability Analysis (ISRA). For this purpose, parametric probability boxes are used to represent lower and upper bounds of the cumulative distribution function for basic random variables with epistemic uncertainties and surrogate models are adaptively trained to reduce computational costs. The obtained results show that neglecting the influence of epistemic uncertainties can lead to permissible operating train speed higher than the speed corresponding to the desired reliability level. In this study, an overestimation of about 13% was observed on average. Furthermore, the rough analyses carried out show that taking epistemic uncertainties into account can lead to a reduction of the system characteristic safety factor by up to 30%. This significant reduction underlines the importance of expanding the available knowledge on the phenomenon of ballast instability.

Influence of impeller clearance, impeller size and baffles on copper sorption on zeolite NaX: Do the size and position really matter?

Even though optimal mixing parameters may significantly influence the sorption process and its costs, the influence of hydrodynamics on sorption in a batch reactor hasn't yet been adequately studied. In this study, the hydrodynamic conditions produced by pitched blade turbine (PBT) impellers of various diameters and positions in baffled and unbaffled reactors were investigated. The objective was to investigate their influence on the just suspended impeller speed (NJS), power consumption per zeolite mass and the sorption process at the same temperature, initial copper solution concentration, and zeolite particle size in all the experiments conducted. The results show that NJS generally decreases as impeller diameter increases and is lower in the reactor without baffles. A transient multiphase computational fluid dynamics model was developed to provide valuable insight into the complex flow kinetics and it was found that the further the impeller is from the bottom of the baffled reactor the wider is the secondary suspension flow and the intensity of the flow below the impeller decreases. For this reason, complete suspension of the NaX zeolite particles in the solution was achieved at a higher PBT impeller speed. Due to the swirling motion of the suspension, this phenomenon is not observed in the unbaffled reactor for all the impellers used besides the smallest one. The power consumption per zeolite mass, at the state of complete zeolite suspension, increases in baffled reactor and decreases in unbaffled reactor with increasing impeller diameter having significantly lower values in the unbaffled reactor. The significantly lower power consumption per zeolite mass in an unbaffled system could be attributed to, not only the generally lower NJS values, but also to the resistance force which baffles make to the tangential fluid flow. The Ritchie model and Mixed surface reaction and diffusion controlled adsorption kinetic model were used for the kinetic analysis of the experimental kinetic data. The kinetic results indicate that the process is faster when the impeller is at the standard of bottom clearance, regardless of the presence of the baffles.

Non-linear thermal radiation and entropy generation on MHD Casson and Williamson hybrid nanofluids across a curved stretching sheet with Cattaneo-Christov heat flux model

This entire study aims to prove the impacts of non-linear thermal radiation and entropy generation on Casson and Williamson hybrid nanofluids through a comparative analysis of the magnetohydrodynamic flow in a porous, curved stretching sheet with the Cattaneo-Christov heat flux model. We used hybrid nanofluid blood based on gold (Au) and Aluminium oxide (Al2O3) nanoparticles. The governing non-linear coupled Partial Differential Equation (PDE) are transformed into non-linear coupled Ordinary Differential Equations (ODE) using the Maple software solver using the Homotopy Perturbation Method. The Homotopy Perturbation Method (HPM) results are compared with the Numerical Method (NM) results, and HPM gives reliable results. The results are provided through the table and graphical representations for several parameters such as velocity, temperature, entropy production, Bejan number, Nusselt number, and skin friction respectively. The velocity profile decreases for Williamson and Casson hybrid nanofluids over a curved stretching sheet while the magnetic field parameters increase. Due to magnetic force associated with Lorentz force, which is known as resistive force, velocity decreases. The Magnetic field on the entropy generation for Casson and Williamson hybrid nanofluids. As the Magnetic field increases, the entropy generation increases for Williamson and Casson hybrid nanofluids. This problem is used in various biomedical situations, including resistive impedance to flow, arteria wall shear stress, and heating impact owing to radiation throughout the surgical process by altering the strength of the applied magnetic field.