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In this investigation, a new micro‐crosslinked anionic polymer resistant to elevated temperature and high salinity, PKDASN, was synthesized using 3‐chloropropyltriethoxysilane (KMB703), N, N‐Dimethylacrylamide (DMAM), 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS), N‐vinyl caprolactam (NVCL), and sodium (4‐vinyl phenyl)methanesulfonate (SVM) employing free radical polymerization in a water‐based solution. The structure of PKDASN was analyzed using Fourier‐transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and X‐ray photoelectron spectroscopy, while its microstructure was analyzed using scanning electron microscopy. Thermogravimetric analysis showed that the pyrolysis temperature of PKDASN was above 294°C. Adding KMB703 enables the polymer to form a dense and stable spatial network. This intensified polymer network could interact with bentonite via intermolecular force and Coulomb force and form a dual grid structure, which presents impressive stability and control of filtration in saltwater. This is mainly achieved through creating a "silane coupling layer" on the particle surface by KMB703, which facilitates the crosslinking and aggregation of the polymer, thereby reinforcing the polymer's framework. This implies that under high‐temperature conditions of 230°C, 3 wt% PKDASN can improve the filtration effectiveness of drilling fluids and exhibit resistance to 15 wt% NaCl contamination. American Petroleum Institute filtration(FLAPI) and High temperature and high pressure filtration(FLHTHP) values were 4.6 and 23.0 mL, respectively. Therefore, this investigation provides a novel approach to utilizing the designated silane agent for the advancement of filtration loss additives in drilling fluids resistant to elevated temperature and high salinity. [ABSTRACT FROM AUTHOR]

This article describes the unsteady translational motion of a porous sphere with slip-surface in a quiescent viscous fluid. Apart from its radius a and density ρs, the particle is characterized by its permeability parameter γ, slip-length l and effective viscosity-ratio ϵ for interior flow. The Reynolds number for the system is assumed to be small leading to negligible convective contribution, though the transient inertia for both the liquid and the solid is comparable to viscous forces. The resulting linearized but unsteady flow-equations for both inside and outside the porous domain are solved in time-invariant frequency domain by satisfying appropriate boundary conditions. The analysis ultimately renders frequency-dependent hydrodynamic friction for the suspended body. The frictional coefficient is computed under both low and high frequency limit for different values of γ, l and ϵ so that the findings can be compared to known results with impermeable surface. Moreover, the parametric exploration shows that the sphere acts like a no-slip body even with non-zero l if aγ ≫ 1/√ϵ . Scaling arguments from a novel boundary layer theory for flow inside porous media near interfaces explain this rather unexpected observation. Also, computed fluid resistance is incorporated in equation of motion for the particle to determine its time-dependent velocity response to a force impulse. This transient response shows wide variability with ρs, γ, l and ϵ insinuating the significance of the presented study. Consequently, the paper concludes that slip and permeability should be viewed as crucial features of submicron particles if unexpected variability is to be explained in nano-scale phenomena like nano-fluidic heat conduction or viral transmission. Thus, the theory and findings in this paper will be immensely useful in modeling of nano-particle dynamics. [ABSTRACT FROM AUTHOR]

We study the effect of Coulomb drag between graphene layers in presence of viscosity term. To do this, we use the simple model of Stokes equations for drift velocities in active and passive layers, known as Pogrebinskii's approach. The solution to these equations allows us to find the potential distribution, and thus the non-local drag resistance of passive layer. It is shown that in viscous regime the non-local resistance may take negative values, in contrast, the ohmic regime results in positive non-local resistance for all drag strengths. Additionally, we discuss the influence of magnetic field on the non-local drag magnetoresistance. [ABSTRACT FROM AUTHOR]

The intricate geological characteristics of tight oil reservoirs, characterized by extremely low porosity and permeability as well as pronounced heterogeneity, have led to a decline in reservoir pressure, substantial gas expulsion, an accelerated decrease in oil production rates, and the inadequacy of traditional water injection methods for enhancing oil recovery. As a result, operators encounter heightened operational costs and prolonged timelines necessary to achieve optimal production levels. This situation underscores the increasing demand for advanced techniques specifically designed for tight oil reservoirs. An internal evaluation is presented, focusing on the application of molecular deposition film techniques for enhanced oil recovery from tight oil reservoirs, with the aim of elucidating the underlying mechanisms of this approach. The research addresses fluid flow resistance by employing aqueous solutions as transmission media and leverages electrostatic interactions to generate nanometer-thin films that enhance the surface properties of the reservoir while modifying the interaction dynamics between oil and rock. This facilitates the more efficient displacement of injected fluids to replace oil during pore flushing processes, thereby achieving enhanced oil recovery objectives. The experimental results indicate that an improvement in oil displacement efficiency is attained by increasing the concentration of the molecular deposition film agent, with 400 mg/L identified as the optimal concentration from an economic perspective. It is advisable to commence with a concentration of 500 mg/L before transitioning to 400 mg/L, considering the adsorption effects near the well zone and dilution phenomena within the reservoir. Molecular deposition films can effectively reduce injection pressure, enhance injection capacity, and lower initiation pressure. These improvements significantly optimize flow conditions within the reservoir and increase core permeability, resulting in a 7.82% enhancement in oil recovery. This molecular deposition film oil recovery technology presents a promising innovative approach for enhanced oil recovery, serving as a viable alternative to conventional water flooding methods. [ABSTRACT FROM AUTHOR]

Supercritical CO2 fracturing technology has shown great potential for enhancing production in unconventional reservoirs. It is essential to clarify the transport mechanism of proppant under the dynamic propagation conditions within rough fractures. A realistic rough fracture model is reconstructed, and Computational Fluid Dynamics simulations are conducted to track proppant movement during fracture propagation. The typical transport characteristics of proppant within rough fractures are revealed, and the effects of fracture propagation rate, proppant density, mass flow rate, particle size, sand ratio, and temperature on the support effect are discussed. The results show that the flow channels formed by sand carrying fluid in rough fractures are complex, with fracture propagation changing some flow channels. The proppant forms an irregular sand bed interspersed with unfilled areas, and complex flow characteristics are generated. The increase in fractal dimension increases the resistance in the fluid flow process and affects the movement of the proppant, which tends to create unfilled areas. Low density and size of proppant can improve the proppant placement length. In a certain temperature range, high temperature injection of sand carrying fluid can improve the proppant placement effect. In addition, the low sand ratio and high mass flow rate pumping can be used to form the dominant channel, followed by pumping with a high sand ratio and low mass flow rate for effective support. [ABSTRACT FROM AUTHOR]

The exploration for knowing the complexity of fractal patterns (Koch snowflake, Julia shape, Chaos pro, Sierpinski triangle and Mandelbrot shape) among the rheological fluid models enables self-similar structures at different scales. In this paper, a fractal–fractional modeling of Newtonian fluid flow is developed for the velocity field by invoking power law kernel. In order to envisage the distinct computational characteristics and applications, the comparative analysis for the Sumudu transform and Laplace transform is investigated for fractal–fractional model of Newtonian fluid under exact analytical solutions. By employing fractal versus non-fractal parameters, analytical solutions for fractal–fractional model of Newtonian fluid by means of fractal Sumudu transform and fractal Laplace transform have been deduced by substituting Δ1 = Δ1 = 1. The sensitivity analysis for fractal–fractional model of Newtonian fluid is also emphasized for the sake of rheological phenomenon via multiple regression, Pearson correlation and probable error. Our results suggest that variations of viscosity depicted the behavior of shear stress on Newtonian fluid and predicted the complex motion under resistance of Newtonian fluid. [ABSTRACT FROM AUTHOR]

Liposils, synthesized via the liposome templating method, offer a promising strategy for enhancing liposome stability by employing a silica coating. This study focuses on the development of nanocarriers utilizing silica-coated nanoliposomes for encapsulating the poorly water-soluble drug, ibrutinib. Ibrutinib-loaded nanoliposomes were meticulously formulated using the reverse-phase evaporation technique, serving as templates for silica coating, resulting in spherical liposils with an average size of approximately 240 nanometers. Comprehensive characterization of the liposil's physical and chemical properties was conducted using various analytical methods, including dynamic light scattering, transmission electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction analysis. Liposils demonstrated superior performance compared to ibrutinib-loaded nanoliposomes, showing sustained drug release profiles in simulated intestinal fluids and resistance to simulated gastric fluid, as confirmed by dissolution studies. Moreover, ibrutinib liposils exhibited a significant increase in half-life (4.08-fold) and notable improvement in bioavailability (3.12-fold) compared to ibrutinib suspensions, as determined by pharmacokinetic studies in rats. These findings underscore the potential of liposils as nanocarriers for orally delivering poorly water-soluble drugs, offering enhanced stability and controlled release profiles, thereby improving bioavailability prospects and therapeutic efficacy. This approach holds promise for addressing challenges associated with the oral administration of drugs with limited solubility, thereby advancing drug delivery technologies and clinical outcomes in pharmaceutical research and development. [ABSTRACT FROM AUTHOR]

Highlights Stab‐resistant armors are important protective gear for the law enforcement officers and security forces. This research attempts to develop stab‐resistant armors for different impact energy levels using multi‐layer neat and shear thickening fluid (STF)‐ treated Kevlar® fabrics. The developed panels were tested using National Institute of Justice's (NIJ) P1 knife at wide range of stabbing energy from 6 to 36 J. The panel containing 16 layers of STF‐treated Kevlar® fabric met the requirements at normal and over‐test conditions showing penetration depth lower than 7 and 20 mm, respectively. For stabbing at high energy level (≥ 24 J), the effect of number of Kevlar® fabric layers was found to be highly beneficial in case of STF‐treated condition and not so for the neat one. STF treatment reduced the stab penetration depth by 40%–68% at 24–36 J energy level without any increase in effective weight of the panel. The fabric‐knife interaction was also studied using a novel sharpness tester and optical microscopy. It was found that the tip of knife deformes and sharpness declines at a faster rate in case of STF‐treated fabric. The study opens up possibilities to explore other materials that would damage the tip of knife during stabbing ensuring better protection. Stab resistant armor has been developed for different energy levels. Effect of number of neat fabric layers is less pronounced at higher energy levels. STF can reduce the penetration depth significantly at high energy levels. Silica particles damage the knife tip during stabbing. STF‐treated panels are lighter and efficacious than their neat counterparts. [ABSTRACT FROM AUTHOR]

On the basis of the known equations of motion of the system of coupled gyrostats by P.V. Kharlamov and the functions of state by S.L. Sobolev, the equations of rotation in a medium with resistance of a free system of two elastically connected rigid bodies with cavities completely filled with an ideal incompressible fluid were derived. Rigid bodies are connected by an elastic restoring spherical joint. Assuming that the center of mass of the rigid bodies is located on the third main axis of inertia and the fluid is ideal, the equation of disturbed motion of the considered mechanical system is obtained in the form of a countable system of ordinary differential equations. In the case of two Lagrangian gyroscopes with arbitrary axisymmetric cavities filled with an ideal fluid, a transcendental characteristic equation has been derived. Taking into account the fundamental tone of liquid oscillations, a characteristic equation of the sixth order was obtained, and on the basis of the Lenard–Schipar criterion, it was written in the innor form, and the conditions for the asymptotic stability of uniform rotation of Lagrange gyroscopes with a liquid were written out in the form of a system of five inequalities. These inequalities are presented in the form of the first, third, sixth, and eighth powers with respect to the coefficient of the spherical joint elasticity. It was proved that if the first tones of liquid oscillations in two cavities are greater than one and do not coincide, then this is sufficient for the higher inequality coefficients to be positive. It was shown that if the first oscillation tones coincide, only the degree of the last inequality decreases, while the higher inequality coefficients remain positive; therefore, internal resonance is impossible. Thus, when the first tones of fluid oscillations are greater than one, the asymptotic stability will always be possible with the increase in the elasticity coefficient. For ellipsoidal cavities, this means that they must be oblate along the axis of rotation. It was shown that in the absence of the spherical joint elasticity, the characteristic equation has a zero root, and the conditions of stability are already presented in the form of a system of four inequalities, which are only necessary. [ABSTRACT FROM AUTHOR]

This study utilized experimental methods involving high-speed cameras to observe the interaction between cavitation bubbles, generated by a low-voltage electric spark device, and particles near a rigid wall. The dynamic characteristics of the particles were analyzed under varying conditions, including different cavitation bubble sizes, particle sizes, and distances between the cavitation bubble and the wall. Two characteristic parameters were introduced: χ for the particle and cavitation bubble sizes, and λ for the cavitation bubble wall distance. Qualitative distinctions were made among types of particle–bubble interactions, and force analysis was conducted under conditions where χ exceeded the threshold χt. The findings reveal that when χ < χt, particle motion is primarily influenced by the jet effects produced by the cavitation bubble. Conversely, when χ > χt, particle motion is dominated by the radiation forces exerted by the cavitation bubble. Under jet-dominated conditions, particle trajectories were observed to be erratic and unpredictable. For cases where λ < 0, the high-speed jet directly impacts the particle. Conversely, for λ > 0, the jet's velocity decays rapidly upon reaching the particle. In scenarios dominated by radiation forces, the cavitation bubble drew particles away from the wall, followed by their free fall back toward it. The influence of gravity, buoyancy, bubble radiation force, fluid resistance, and virtual mass force on particles was studied when radiation forces prevailed. The acceleration formula for particles was derived through the application of the bubble dynamics equation and was refined based on experimental observations. [ABSTRACT FROM AUTHOR]

With the increasing popularity of vertical axis turbines (VATs), researchers are now focusing on their performance improvement. Instead of adopting conventional means of performance improvements such as augmentation techniques and exhaustive parametric design optimization, the bio-inspired turbine designs have become a center of attraction, especially during the last decade. This review article attempts to compile the bio-inspired designs belonging to the VATs. Bio-inspired designs implemented in Savonius, Darrieus, Nautilus, and Seed-inspired turbines are elaborated besides giving a detailed explanation of the corresponding bio-organism and natural phenomenon. How the working principles of bio-organisms emulated in the form of fluid dynamic design are explained thoroughly in this paper. The bio-inspired designs for VATs are then classified pragmatically for the future designs. Research gaps are highlighted for the aspiring researchers, and this is followed by the important strategies and allied challenges. [ABSTRACT FROM AUTHOR]

The fluid pump was the key component of the formation tester; the pump cylinder, piston, and piston rod of the fluid pump often suffer from wear scratches and seal failure, which greatly reduces the service reliability of the instrument. To improve the wear resistance of the fluid pump, 17-4PH steel specimens were treated by boronizing at 750 °C for 20 h. Specimens with and without boronizing were studied by OM, SEM, XRD, microhardness test, and wear resistance test. Layers of about 60 μm thickness formed during boronization contain a mixture of FeB, CrB, and α(B)-Fe phases, which leads to a significant improvement in microhardness (from 336 to 980 HV) and wear rate (from 16.4 × 10−5 mm3/Nm to 3.3 × 10−5 mm3/Nm). The pump cylinder and the fluid-pump piston rod were boronized and assembled into the pumping module, which passed the indoor durability test for 90 h and did not show obvious surface wear after 60 h of field experience. For the first time, the boronization process extends the service time of the fluid pump, improving the wear resistance of the pump cylinder and piston rod. [ABSTRACT FROM AUTHOR]

Radial well filled with phase change material has been proposed as a novel sand control method for hydrate exploitation. In order to reveal the sand control mechanism, CFD-DEM coupling method is applied to simulate the migration, settlement, and blockage processes of sand particles in the radial well. The obtained results indicate that three scenarios have been recognized for sand particles passing through sand control medium, based on the diameter ratio of sand control medium to sand particle (Dd): fully passing (Dd = 8.75-22.5), partially passing and partially blocked (Dd = 3.18-5.63), and completely blocked (Dd = 2.18-3.21). After being captured by the sand control medium, sand particles can block pores, which increases fluid flow resistance and causes a certain pressure difference in the radial well. The pressure in the radial well should be lower than the hydrate phase equilibrium pressure during sand control design, for the purpose of promoting hydrate decomposition, and sand capture. The length of the radial well should be optimized based on the reservoir pore pressure, production pressure difference, bottom hole pressure, and the pressure gradient in the radial well. It should be noticed that the sand control medium leads to a decrease in permeability after sand particles captured. Even the permeability is reduced to several hundred millidarcy, it is still sufficient to ensure the effective flow of gas and water after hydrate decomposition. Increasing fluid velocity reduces the blocking capacity of the sand control medium, mainly because of deterioration in bridging between sand particles. [ABSTRACT FROM AUTHOR]

As drilling wells continue to move into deep ultra-deep layers, the requirements for temperature resistance of drilling fluid treatments are getting higher and higher. Among them, blocking agent, as one of the key treatment agents, has also become a hot spot of research. In this study, a high temperature resistant strong adsorption rigid blocking agent (QW-1) was prepared using KH570 modified silica, acrylamide (AM) and allyltrimethylammonium chloride (TMAAC). QW-1 has good thermal stability, average particle size of 1.46 mm, water contact angle of 10.5°, has a strong hydrophilicity, can be well dispersed in water. The experimental results showed that when 2 wt% QW-1 was added to recipe A (4 wt % bentonite slurryþ0.5 wt% DSP-1 (filtration loss depressant)), the API filtration loss decreased from 7.8 to 6.4 mL. After aging at 240 °C, the API loss of filtration was reduced from 21 to 14 mL, which has certain performance of high temperature loss of filtration. At the same time, it is effective in sealing 80-100 mesh and 100-120 mesh sand beds as well as 3 and 5 mm ceramic sand discs. Under the same conditions, the blocking performance was superior to silica (5 mm) and calcium carbonate (2.6 mm). In addition, the mechanism of action of QW-1 was further investigated. The results show that QW-1 with amide and quaternary ammonium groups on the molecular chain can be adsorbed onto the surface of clay particles through hydrogen bonding and electrostatic interaction to form a dense blocking layer, thus preventing further intrusion of drilling fluid into the formation [ABSTRACT FROM AUTHOR]

To reduce the fluid resistance on the surface of flow-through components and improve energy utilization efficiency, a biomimetic fitting structure model is constructed based on the ridge-like features of beluga skin. The SST k-ω model is employed to numerically simulate the drag reduction characteristics of three biomimetic structures (fitting structure, V-shaped structure, and arc structure) included in the design. The variations of the fitting structure's viscous resistance and pressure drop resistance with different widths and depths are compared. The drag reduction mechanism of the fitting structure surface is studied based on the pressure stress, velocity field, and shear stress. The results demonstrate that the fitting structure exhibits the best drag reduction performance. The fitting structure with a width of 30 mm and a depth of 0.7 mm achieves an optimal drag reduction effect of 4.18%. The fitting structure exhibits a large low shear stress region, which increases the thickness of the bottom boundary layer, thereby reducing surface velocity and viscous resistance. [ABSTRACT FROM AUTHOR]

Improving the therapeutic management of HIV‐positive persons is a major public health issue and includes better detection of drug resistance mutations (DRMs). The aim of this study was (i) to explore DRMs in HIV‐1‐positive persons presenting a blood viral load (VL) < 1000 genomes copies (gc)/mL, including the analyze of cerebrospinal fluid (CSF) and HIV‐DNA from peripheral blood mononuclear cells using ultradeep sequencing (UDS) and (ii), to evaluate how these DRMs could influence the clinical practices. For each patient (n = 12), including five low‐VL patients (i.e., <1000 gc/mL), HIV‐1 UDS targeting the protease, reverse transcriptase and integrase genes was performed on plasma, proviral DNA, and CSF when available. Sequencing discordances or failures were mostly found in samples from low‐VL patients. A 5% UDS cut‐off allowed to increase the sensitivity to detect DRMs in different compartments, excepted in CSF. Patients with the highest viral quasispecies heterogeneity were naïve of treatment or presented a medical history suggesting low selection pressure or virological failures. When analyzing compartmentalization and following‐up patients: low‐frequency variants (LFVs) were responsible for 47% (n = 8) and 76% (n = 13) of changes in drug resistance interpretation, respectively. In such cases, we conclude that UDS is a robust technique, which still could be improved by increase the RNA and/or DNA extraction in low‐VL samples to detect LFVs. Further studies are needed to define the impact of LFVs on antiretroviral treatments. At last, when considering a DRM, the use of mutational load would probably be more suitable than frequencies. [ABSTRACT FROM AUTHOR]

This study explores the impact of additive manufactured porous architecture on the tribological performance of Ti6Al4V. Biomimetic porous architectures were manufactured on dense multi-layer using direct energy deposition with a dense layer followed by a porous layer. Varied scanning intervals during laser processing for the porous layer influenced the microstructure and, consequently, the hardness, the corrosion resistance and the tribological behavior of the dense layer. The results indicate a substantial improvement in tribocorrosion performance, particularly noteworthy in reducing corrosive wear rates, making porous architectures beneficial for both biomimetic structures and enhanced tribocorrosion resistance in body fluids. [ABSTRACT FROM AUTHOR]

Immersed nonlinear elements are prevalent in biological systems that require a preferential flow direction, such as the venous and the lymphatic system. We investigate here a certain class of models where the fluid is driven by peristaltic pumping and the nonlinear elements are ideal valves that completely suppress backflow. This highly nonlinear system produces discontinuous solutions that are difficult to study. We show that, as the density of valves increases, the pressure and flow are well approximated by a continuum of valves which can be analytically treated, and we demonstrate through numeric simulation that the approximation works well even for intermediate valve densities. We find that the induced flow is linear in the peristaltic amplitude for small peristaltic forces and, in the case of sinusoidal peristalsis, is independent of pumping direction. Despite the continuum approximation used, the physical valve density is accounted for by modifying the resistance of the fluid appropriately. The suppression of backflow causes a net benefit in adding valves when the valve density is low, but once the density is high enough, valves predominately suppress forward flow, suggesting there is an optimum number of valves per wavelength. The continuum model for peristaltic pumping through an array of valves presented in this work can eventually provide insights about the design and operating principles of complex flow networks with a broad class of nonlinear elements. [ABSTRACT FROM AUTHOR]

Shear thickening fluid (STF), a highly concentrated mixture of nanosized silica particles in polyethylene glycol (PEG) is characterized by its quick transition to a stiff, solid‐like form under high shear rates. In this study, the modified Stöber synthesis approach was used for synthesizing the monodispersed spherical 300 nm silica nanoparticles. The rheological properties of the STF formulated using different silica loading were characterized. The Takshak model was tested to assess the rheological properties. The effect of the STFs on the impact resistance and yarn pull‐out force of the Kevlar® 802 fabric was determined. The uniformity in size of the silica nanoparticles facilitated more efficient packing within the fluid matrix, resulting in the formation of networks or structures that enhance shear thickening behavior. The STF with 70% silica exhibited the best peak viscosity of 45.8 Pa.s. Upon impregnation of this STF onto the Kevlar, a significantly high energy absorption (478.4%) compared to neat Kevlar, was observed. Moreover, the yarn pull‐out force for this system was found to be very high (435.8%). The reasons for the enhancement of the properties are explained. The novelty of this work lies in the synthesis of silica particles, analysis of the rheological properties, and interrelating the rheological properties with the characteristic parameters to define the impact characteristics. The improved properties underscore the suitability of synthesized STF for impact resistance applications. [ABSTRACT FROM AUTHOR]

Electroosmotic flow (EOF) in a fractal tree‐like microfluidic network has wide applications. To reduce the fluid resistance of EOF in the network, this paper numerically studies the influences of the branch convergence α, the level convergence κ, the length ratio λ, the branching number N, the maximum branching level M, and the channel height H of a fractal tree‐like convergent microchannel network (FTCMCN) on the EOF flowrate and analyzes the optimal structure of FTCMCN to maximize the EOF transport efficiency. The present paper finds the optimal structure of FTCMCN and its dependence on the various geometric and structural parameters. This work is beneficial to the optimization design of the FTCMCN to achieve the highest EOF transport efficiency. [ABSTRACT FROM AUTHOR]

An assay of the regime and constructive approaches to the strengthening of heat and mass transfer procedures has made it possible to outline the direction of development of heat and mass transfer devices that implement vortex interaction of flows when flowing around regularly placed packed elements, which in turn perform vibrational or rotational motions. As a consequence of the pursued investigations of the device involving a regular rotating packing, graphical dependencies of the rotation frequency of the packed elements, fluid resistance, the quantity of retaining liquid and the gas concentration of the layer in the device on the gas rate and irrigation density have been received. On the ground of the pursued investigations, a methodology for calculating the rotation parameters of packed elements and hydrodynamic characteristics is proposed, including equations for calculating the rotation frequency of packed elements, fluid resistance, the quantity of retaining liquid and the gas concentration of the layer. [ABSTRACT FROM AUTHOR]

Liquid-phase adsorption technology has been widely applied to address environmental problems related to the removal of pollutants from aqueous streams. Simple and effective methods for determining mass transfer parameters, including intra-particle and fluid-to-solid film resistances, are crucial for designing adsorption processes. The efficient simplified diffusion technique (ES technique), based on a completely mixed batch reactor (CMBR), is proposed in this study to address these needs. In this study, we compare three diffusivity (Ds) determination methods: the rigorous diffusion technique (R technique), the simplified diffusion technique (S technique), and the ES technique. Although the simulation results from the R technique are excellent, it is a very complicated and time-consuming approach that is not convenient for practical use. The S technique provides a much simpler approach, but its results are only valid in cases where the contribution of fluid film resistance is negligible (Biot number > 40). The ES technique proposed in this study can overcome those limitations. The estimation errors of the ES technique are significantly smaller than that of the S technique when compared with the R technique. The proposed ES technique would be very useful for field applications to determine diffusivity for aqueous adsorption systems. [ABSTRACT FROM AUTHOR]

Fluidic actuation systems are optimizable as to energy consumption by reducing the friction in the hydraulic cylinders. Polymeric materials with special antifriction properties and good resistance to hydraulic fluids can be deployed to enhance the performance of hydraulic cylinders. Small friction forces can also be ensured by facilitating the hydrodynamic separation of the elements of the friction tribosystem, namely the seal and sealed-off surface, respectively. The study presented in this paper analyzed the hydrodynamic separation phenomenon in hydraulic cylinders with coaxial sealing systems of the pistons. The process underlying the forming of the fluid film between the seal and its contact surface was considered and the formula for calculating film thickness was deduced. This paper presents graphs that describe the variation of the fluid film thickness versus the dimensional and material characteristics of the sealing systems. The study yielded recommendations as to the most adequate polymeric material to be used and the optimum dimensional characteristics of the seal. [ABSTRACT FROM AUTHOR]

The high-speed coolant pump facilitates thermal regulation in electric vehicle components, including batteries and motors, by circulating an ethylene glycol solution. This commonly used circulating fluid exhibits a notable negative correlation with temperature in terms of viscosity. Numerical simulations investigate the transient dynamics of a high-speed coolant pump operating at 6000 rpm, driving coolant flow at various temperatures. A high-speed coolant pump test rig is established, and the performance is evaluated under different temperature conditions. The numerical simulations at different temperatures align well with the experimental outcomes. Decreasing temperatures, from 100 to −20 °C, lead to reduced pump head and efficiency due to increased viscosity. Specifically, at a flow rate of 30 L/min, head decreases by 40.03% and efficiency by 44.19%. With escalating viscosity, the best efficiency point shifts toward lower flow rates. Notable impacts on both disk efficiency and hydraulic efficiency are observed due to viscosity fluctuations. It exerts minimal influence on volumetric efficiency at elevated flow rates but has a substantial impact on volumetric efficiency at lower flow rates. Increased fluid viscosity causes uneven pressure distribution within the pump, altering velocity profiles within the impeller. High-viscosity fluids tend to form large-scale vortex structures around the blades, reducing the thrust exerted by the blades on the fluid. Higher viscosity results in larger vortex structures around the blades, reducing thrust and increasing fluid frictional resistance. The study findings provide valuable insights for the advancement of high-efficiency, energy-saving, high-speed coolant pumps tailored for electric vehicles. [ABSTRACT FROM AUTHOR]

Accurate prediction of pressure caused by plunging jets of high spillways is essential for assessing the bed rock scour initiation and expansion. The hydrodynamic pressure characteristics at plunge pools' bottom and inside rock joints are assessed based on the experimental results and the analysis of extensive available library experimental data. A new empirical model of mean dynamic pressure coefficient, the CP , and pressure fluctuation, the CP′ , for core and developed jets at stagnation point are presented. The effects of jet break-up ratio (L/Lb), the jet's fall height L to the jet break-up length Lb ratio, on CP and CP′ at the pool bottom and inside the rock joints are assessed. The maximum CP at pool bottom and inside rock joint occurs in L/Lb≤1.2 range while the maximum CP′ occurs within 0.85

Superhydrophobic surfaces have garnered attention for their ability to decrease fluid resistance, which can significantly reduce energy consumption. This study aims to accurately capture critical flow phenomena in a microchannel and explore the internal drag-reduction mechanism of the flow field. To achieve this, the three-dimensional (3D) superhydrophobic surface flow field with conical microstructure is numerically simulated using the gas-liquid two-phase flow theory and Volume of Fluid (VOF) model, combined with a Semi-implicit method for the pressure-linked equation (SIMPLE) algorithm. The surface dragreduction effect of the conical microstructure is investigated and compared it to that of the V-longitudinal groove and V-transverse groove surfaces. Additionally, the changes in the drag-reduction effect during the wear of the conical microstructure were explored. The numerical results reveal that the dragreduction effect improves with a larger period spacing of the conical microstructure, the drag reduction rate can reach 25.23%. As the height of the conical microstructure increases, the aspect ratio (ratio of width to height) decreases, and the dimensionless pressure drop ratio and the drag-reduction ratio increase. When the aspect ratio approaches 1, the drag reduction rate can reach over 28%. indicating a more effective drag-reduction. The microstructure is most effective in reducing drag at the beginning of the wear period but becomes less effective as the wear level increases, when the high wear reaches 10, the drag reduction rate decreases to 3%. Compared to the V-shaped longitudinal groove and V-shaped transverse grooves, the conical microstructure is the most effective in reducing drag. [ABSTRACT FROM AUTHOR]

Exact solutions for the dynamics of incompressible fluids showing rate-type behavior have mostly been found in circumstances where the boundary velocities are given in the body of existing research. This phenomenon results from the constitutive equation of the corresponding extra-stress tensor, which specifies the natural relationship between velocity and shear stress. In this paper, we focus on a unique observation of the magnetohydrodynamic (MHD) movements of incompressible Maxwell fluids, and the governing equations regulating velocity and shear stress. We focus our analysis on the case of an infinite plate submerged in a porous substance. Within this framework, we do an analytical analysis of a motion issue with a boundary that has a predetermined shear stress. We can easily ascertain the shear stress associated with the motion brought on by a flat plate in order to be more exact. The fluid is subjected to a shear stress by this plate that changes over time. The velocity field from a boundary motion with a predetermined velocity is used to achieve this. We give two graphical representations of individual solutions for the sake of clarity and result verification. Last but not least, we use graphical depiction to highlight how a magnetic field and a porous media affect the fluid’s flow resistance. The results show that the flow resistance of the fluid increases in the presence of a porous media and decreases when a magnetic field is present. [ABSTRACT FROM AUTHOR]

This research introduces an Artificial Intelligence (AI) based model designed to concurrently optimize energy supply management, biocide dosing, and maintenance scheduling for heat exchangers. This optimization considers energetic, technical, economic, and environmental considerations. The impact of biofilm on heat exchangers is assessed, revealing a 41% reduction in thermal efficiency and a 113% increase in flow frictional resistance of the fluid compared to the initial state. Consequently, the pump's power consumption, required to maintain hydraulic conditions, rises by 9%. The newly developed AI model detects the point at which the heat exchanger's performance begins to decline due to accumulating dirt, marking day 44 of experimentation as the threshold to commence the antifouling biocide dosing. Leveraging this AI model to monitor heat exchanger efficiency represents an innovative approach to optimizing antifouling biocide dosing and reduce the environmental impact stemming from industrial plants. [ABSTRACT FROM AUTHOR]

This paper conducts a comprehensive analysis of undulating and oscillatory movements in fish, utilizing numerical simulations to explore correlations among fin thrust and swimming speed. The study distinguishes itself through a unique approach by employing kinematic equations of motion control, specifically in oscillation and undulation, for computational fluid dynamics. Despite increasing energy loss with undulation, the study reveals a reduction in power demand with oscillation, underscoring its effectiveness in achieving desired speeds. The dynamics of undulating fins in aquatic and aerial locomotion remain insufficiently understood. The trade-off between more energy-consuming but highly propulsive movements or simpler and faster movements requires sophisticated design techniques to reduce volume. The geometry, developed using Rhino 6 software, incorporates precise fluid resistance calculations conducted with Ansys Fluent 19. Spanning flow velocities from 1 to 4 m/s were used for the simulation condition. Critical factors such as flexibility, viscosity, and shape change were meticulously examined for their impact on efficiency enhancement. [ABSTRACT FROM AUTHOR]

As a classical gas-solid two-phase flow system, the processes of fiber filtering microparticles are prevalent in nature and engineering. However, the impact of microparticle shape on fiber filtration processes is still largely unexplored. Herein, using the self-developed spheropolyhedral-based discrete element lattice Boltzmann method, the filtration process of non-spherical microparticles through a single fiber is investigated. Results show that the single fiber efficiency (SFE) for non-spherical particles exhibits a trend of initially increasing and subsequently decreasing trend with the increase in Stokes number (St), which is similar to the case of spherical particles. However, it is interesting to note that the peak values of SFE increase significantly with decreasing particle sphericity (ψ) and the corresponding St values become larger. As ψ decreases from 1.0 (sphere) to 0.671 (tetrahedron), the SFE increase from 0.205 to 0.49 and the corresponding St rises from 1.0 to 1.75. The enhanced SFE can be explained by elevated collision probability and adhesion probability, based on detailed particle kinematics and dynamics behavior analysis as well as microscopic depositional structure evaluation. The depositional structures of the non-spherical particles have larger capture areas, leading to higher initial collision probabilities. Meanwhile, the anisotropic collisions between non-spherical particles and fibers greatly contribute to higher secondary collision probabilities. In addition, compared to spherical particles of the same volume, the non-spherical particles experience greater fluid resistance, resulting in lower initial collision velocities and larger initial adhesion probabilities. The face-to-face contacts between non-spherical particles also lead to stronger interparticle adhesion and enhanced adhesion probabilities. [ABSTRACT FROM AUTHOR]

The starting rotation of a porous sphere induced by the sudden application of a continuous torque about its diameter at the center of a spherical cavity filled with an incompressible Newtonian fluid at low Reynolds numbers is analyzed. The unsteady Stokes and Brinkman equations governing the fluid velocities outside and inside the porous particle, respectively, are solved via the Laplace transform, and an explicit formula of its dynamic angular velocity as a function of the pertinent parameters is obtained. The behavior of the start-up rotation of an isolated porous particle and the cavity wall effect on the particle rotation are interesting. The angular velocity of the particle grows incessantly over time from an initial zero to its final value, while the angular acceleration declines with time continuously. In general, the transient angular velocity is an increasing function of the porosity of the particle. A porous sphere with higher fluid permeability rotates at higher angular velocity and acceleration relative to the reference particle at any elapsed time but lags behind the reference particle in the percentage growth of angular velocity towards the respective terminal values. The transient angular velocity decreases with increasing particle-to-cavity radius ratio, but it is not a sensitive function of the radius ratio when the resistance to fluid flow inside the porous particle or the radius ratio itself is small. [ABSTRACT FROM AUTHOR]

This study's primary objective is to investigate the Jeffery–Hamel model and entropy generation in the magnetohydrodynamic (MHD) flow of hybrid nanofluid across stretching, shrinking, converging, and diverging channels. Aluminum oxide (Al2O3) and silver (Ag) are nanoparticles, using blood as the base fluid. The controlling nonlinear coupled partial differential equations (PDEs) are transformed into ordinary differential equations (ODEs) with similarity transformations and then solved using the Homotopy Perturbation Method (HPM) and shooting technique (Bvp4c). The HPM is compared to the numerical method (NM), and the results are more accurate and reliable. The effects of velocity, temperature, entropy generation, and the Bejan number on physical parameters like a magnetic field, the Reynolds number, magnetic field, and the Brinkman number are discussed through graphs. The heat transfer and skin friction coefficients are also studied and portrayed as graphs and tables. The influence of a magnetic field on the velocity profile of stretching and shrinking through converging and diverging channels. When increasing the magnetic field, the velocity profile increases. Physically, an increase in the magnetic field produces a higher Lorentz force, which improves fluid resistance and restricts fluid particle flow within the given topology. The temperature profile decreases in the stretching and shrinking of converging channels as magnetic field values rise. As well as the opposite behavior observed in stretching and shrinking for diverging channels. In this model, biomedical applications include studying physiological systems, surgical procedures, nano-pharmacological delivery systems, and nano-mediated treatment of atherosclerosis. [ABSTRACT FROM AUTHOR]

In an effort to enhance the heat transfer performance of solar collectors, this paper proposed to replace the smooth tube with symmetrical and asymmetrical transversely corrugated tubes, and to couple with SiO2‐H2O nanofluids for heat transfer of solar collectors. Effects of nanofluids mass fraction (w =.0%,.1%,.3%, and.5%), Reynolds number (3000, 4000, 5000, 6000, and 7000), and groove radius (1.5, 2, and 2.5 mm) on the flow and heat transfer properties of nanofluids in solar collectors were studied. The comprehensive evaluation index was used to consider the heat transfer property and flow resistance of fluid flow at the same time. Results showed that with the augment of nanofluids mass fraction, Reynolds number, and groove radius, the heat transfer enhancement performance of the collector becomes better. Among them, when the Reynolds number is 4000, the asymmetric transversely corrugated tube with a nanofluids mass fraction of.5% and a groove depth of 2.5 mm has the best comprehensive flow and heat transfer performance, and the comprehensive evaluation index can reach 1.62. The study results in this paper are beneficial to the coupling of nanofluids and transversely corrugated tubes and their application in the domain of enhanced heat transfer of solar collectors. [ABSTRACT FROM AUTHOR]

This paper presents a MEMS electrochemical angular accelerometer with a silicon-based four-electrode structure, which was made of thousands of interconnected microchannels for electrolyte flow, anodes uniformly coated on structure surfaces and cathodes located on the sidewalls of flow holes. From the perspective of device fabrication, in this study, the previously reported multi-piece assembly was simplified into single-piece integrative manufacturing, effectively addressing the problems of complex assembly and manual alignment. From the perspective of the sensitive structure, in this study, the silicon-based four-electrode structure featuring with complete insulation layers between anodes and cathodes can enable fast electrochemical reactions with improved sensitivities. Numerical simulations were conducted to optimize the geometrical parameters of the silicon-based four-electrode structure, where increases in fluid resistance and cathode area were found to expand working bandwidths and improve device sensitivity, respectively. Then, the silicon-based four-electrode structure was fabricated by conventional MEMS processes, mainly composed of wafer-level bonding and wafer-level etching. As to device characterization, the MEMS electrochemical angular accelerometer with the silicon-based four-electrode structure exhibited a maximum sensitivity of 1458 V/(rad/s2) at 0.01 Hz and a minimum noise level of −164 dB at 1 Hz. Compared with previously reported electrochemical angular accelerometers, the angular accelerometer developed in this study offered higher sensitivities and lower noise levels, indicating strong potential for applications in the field of rotational seismology. [ABSTRACT FROM AUTHOR]

This is a feasibility study of resistance hydro rotary draw bending of titanium tubes with small and critical bending ratios. A heating resistance device was designed and fabricated for bending titanium tubes with a fluid mandrel. The results show that with simultaneous application of resistance heating and fluid pressure in the tubes during the rotary bending process, the springback and ovality of the tubes cross-section at bending area decreased, and the wrinkles in the bending area were evenly distributed. It was also observed that increasing the pressure at 120 bar and heating the tube to a temperature of 300 °C, reduced the cross-sectional distortion. Finally, it will be shown that the proposed new process can be used for bending titanium tubes and the minimum distortion of the cross-section at 100 bar and 400 °C was obtained 2.1 %. [ABSTRACT FROM AUTHOR]

From their initial application to the fields of chemistry and biology, microfluidic chips used as micro total analysis systems have developed into new technologies to satisfy the requirements of various societal industries. Microchannels are essential components of microfluidic chips; they play a vital role in connecting the inlet and outlet as well as determining the flow distribution and reagent mixing. Microfluidic research has always been devoted to minimizing energy dissipation, fluid resistance, and pressure drop to realize energy-efficient microfluidic chips. This study proposes a new theory for manipulating the flow in microchannels based on hydrodynamic metamaterials according to the spatial transformation theory. In particular, hydrodynamic metamaterials are specifically designed to construct flow shifters, flow splitters, and flow combiners, and theoretical and numerical simulations are performed to assess their hydrodynamic performance. The systematic design of hydrodynamic metamaterial devices proposed in this work establishes a theoretical framework to achieve a steady flow state without inducing unstable flow disturbances in complex-shape microchannels. [ABSTRACT FROM AUTHOR]

The rapid advancement in Lithium‐ion battery technology has significantly boosted the electric vehicle market worldwide. These batteries are highly sought after by automobile manufacturers and researchers due to their exceptional energy storage and power capabilities. However, efficient working temperatures ranges from 15°C to 35°C, making it essential to implement battery cooling and heating methods to maintain optimal performance. This study primarily focuses on battery cooling. The automotive manufactures have focused on ethylene glycol, water and synthetic oils as commonly used coolants for keeping the lithium‐ion battery pack within working temperature limits. However, these fluids have lower heat conduction, leading to reduced heat transfer rates and diminished cooling performance. To address this issue, nano‐enhanced fluids, which are engineered fluids containing suspended nanospheres, have been explored. The heat transfer properties of conventional coolants are increased using nano‐enhanced fluids, thereby improving heat conduction and promoting efficient heat transfer within the battery. The study compares the temperature‐related characteristic of different nano‐enhanced fluids, including oxides of copper (CuO), titanium (TiO2), aluminum (Al2O3), silicon (SiO2), and zinc (ZnO), when added to base fluids such as synthetic oils, water and ethylene glycol. The importance to capacity of specific heat, conductivity of fluid thermally, fluid resistance to flow and fluid volumetric mass which are affected by changes in temperature limits are stressed upon. Depending on the specific application and test conditions, the effectiveness of one nano‐enhanced fluid may outperform the others. In conclusion, the thermo physical properties of nanofluids play a critical role in maintaining the battery pack temperature within operating temperature limits. The selections of nanofluids for particular battery thermal management system depends upon its arrangement along the battery pack and cell geometry. The cooling performance using nanofluids as coolant is 10% to 15% higher than the conventional used fluids. This nano‐enhanced fluid show great promise in enhancing the cooling capabilities of battery cooling systems, contributing to improved Lithium‐ion battery performance in electric vehicles. [ABSTRACT FROM AUTHOR]

The impact of the column number of ellipsoidal dimples on a highly-loaded compressor cascade (NACA65-K48) under design conditions was investigated by using a numerical simulation method. Ellipsoidal dimples with a thickness of 0.2 mm were located at the position of chord length ranging from 10% to 36%. The span-wise interval was 5.0 mm. The performance and flow field structures of cascades with 1 to 5 ellipsoidal dimpled columns were compared, and the results showed that the turbulent kinetic energy intensity near the wall was enhanced and the fluid separation resistance was consequently improved. The total pressure loss was reduced by all modified ellipsoidal dimples. In addition, the separation bubble of the suction side was broken or weakened, the corner separation was improved, and the influence range of the passage vortex was reduced. Moreover, the improvement effect of cascade performance parameters initially increased with the increase in the number of dimple columns and then reduced as the number of columns was further increased. The reductions in the total pressure loss of the cascade were 0.59%, 1.47%, 1.69%, 1.91%, and 1.73% for column numbers 1 to 5, respectively. [ABSTRACT FROM AUTHOR]

The rheological behaviors of suspended sediments are crucial for investigating near‐bed particle dynamics; for these investigations, the viscosity of a highly concentrated suspension is primarily focused on quantifying its resistance to deformation. By using a rotational viscometer, the relationships between relative viscosities (ηr) for different sediment types and their volumetric concentrations (ϕ) are studied for low‐to high‐concentration slurries. The results show that the conventional Einstein formula for diluted sand severely underestimates ηr. In the case of pure silts and non‐cohesive quartz, ηr demonstrates a gradual linear increase, reaching values around order of 101 as ϕ increases within the range of 0.2–0.4. Meanwhile, the ηr values of clays exhibit an exponential rise before leveling off at a plateau. Specifically, the ηr values of kaolinite, montmorillonite, and bentonite rise with ϕ lower than 0.3 and reach to plateau of values of thousands, which rise more rapidly than chlorite and illite. The modified viscosity model based on Costa (2005, https://doi.org/10.1029/2005GL024303) agrees reasonably well with observations and produces similar ηr ∼ ϕ relationships. In addition, the model is coupled with a hydrodynamic model to simulate the deposition of a thickened tailings slurry and a one‐dimensional dam break. The proposed model performs well in predicting the quasi‐equilibrium profiles of the non‐Newtonian fluid, which are validated by available analytical solutions. The results suggest that future models should be focused on the effects of flow properties, especially for non‐Newtonian fluids, and on large‐scale modeling applications, which can increase the accuracy of predictions of the transport characteristics of sediments and pollutants in rivers, lakes, and coastal areas. Plain Language Summary: Viscosity describes the resistance of a fluid, and it is defined as the ratio of shear stress to shear rate. Flow that is laden with sediment particles increases relative viscosity (ηr). Einstein (1906, https://doi.org/10.3929/ethz‐a‐000565688) conducted pioneering work to relate ηr with solid volumetric concentration (ϕ); this work is valid for dilute suspensions with coarse, non‐cohesive particles. Nevertheless, the near‐bed layer in muddy coastal waters is usually abundant with hyper‐concentrated cohesive sediment flocs, which may result in deviations using conventional equations for the viscosity. In this study, 79 experiments with eight different sediments (i.e., five clays, two silts, and quartz) are conducted to investigate the ηr ∼ ϕ relationship. We propose a modified viscosity model to further illustrate the impacts of sediment concentration, composition, and size on relative viscosity. For this model, only one parameter can be adjusted based on our experimental results with different minerals. In future research, our model could be expanded to incorporate the influence of mud/sand fractions, thereby capturing the rheological characteristics of mixed sediments more comprehensively. Key Points: The relative viscosity was measured for clays, silts, and quartz under different concentrations or flow environments by using a viscometerThe conventional Einstein formula severely underestimates the relative viscosity for fluid containing high concentrated cohesive sedimentsAn improved viscosity model was proposed to predict the ηr ∼ Φ relationship for different sediment suspensions [ABSTRACT FROM AUTHOR]

In the pursuit of enhancing the efficiency of ships and underwater vehicles, overcoming fluid drag is a pivotal challenge. Among the many drag reduction strategies, the bionic nonsmooth surface drag reduction technique is promising. In the initial phases of surface drag reduction technology development, the prevailing belief was that smoother surfaces would yield superior drag reduction. However, as under standing of drag reduction mechanisms improved, it became evident that surface fluid resistance is intricately linked to the boundary layer. Consequently, research shifted focus toward delaying surface turbulence transition and mitigating turbulence bursts. Inspired by the nonsmooth epidermis of pufferfish, this study designed nonsmooth surfaces for drag reduction experiments, and the circulating water tunnel experimental method based on particle image velocimetry technology yielded satisfactory experimental outcomes in measuring the drag reduction rate of nonsmooth surfaces. However, this methodology faces limitations in terms of time consumption and complex data processing, particularly with large sample sizes. To overcome these challenges, this study investigated the relationship between the spreading spacing, the friction drag reduction rate, and the total drag reduction rate based on the nonsmooth surface drag reduction simulation experiment of Fluent. The process involved designing nonsmooth surface models with different parameters in SolidWorks, followed by mesh delineation in the integrated computer engineering and manttfacturing (ICEM), and subsequent importation into ANSYS for finite element analysis using the Fluent module. The shear stress tramsfer (SST) k--ω turbulence model was adopted for the numerical simulation of drag reduction on these surfaces, and the results of the numerical simulation were obtained using the postprocessing module CFD-post. The results showed the following. With the increase in the spreading spacing of the conical microstructures, the total drag reduction rate of the nonsmooth surface increased. At low flow velocities, the spreading spacing did not have much influence on the total drag reduction rate; at high flow velocities, the larger the spreading spacing, the higher the total drag reduction rate. If the spreading spacing was unchanged, the total drag reduction rate decreased with the increase in the flow velocity. At the same time, with the increase in the spreading distance of the conical microstructures, the friction drag reduction rate of the nonsmooth surfaces decreased, and the friction drag reduction rate showed a decreasing trend when the incoming flow rate was accelerated with the constant spreading distance of the conical microstructures. Further analysis of cloud diagrams indicated that the bionic cone microstructures disrupted large-scale vortex structures in the turbulent boundary layer, transforming them into smaller vortices while absorbing turbulence energy. This process curtailed momentum transfer within the layer and inhibited turbulence bursting, which led to the higher flow velocity, pressure, and turbulence kinetic energy upstream of the cone microstructure and the lower flow velocity, pressure, and turbulence kinetic energy in the two sides and the backside. The nonsmooth surfaces investigated in this study provide not only a new highlight for the design of drag-reducing surfaces but also a novel method of fluid drag reduction for ship, underwater vehicle, and pipeline transportation applications. [ABSTRACT FROM AUTHOR]

The article presents a summarised history of the equations governing fluid motion, known as the Navier–Stokes equations. It starts with the work of Castelli, who established the continuity equation in 1628. The determination of fluid flow resistance was a topic that involved the brightest minds of the 17th and 18th centuries. Navier's contribution consisted of the incorporation of molecular attraction effects into Euler's equation, giving rise to an additional term associated with resistance. However, his analysis was not the only one. This continued until 1850, when Stokes firmly established the boundary conditions that must be applied to the differential equations of motion, specifically stating the non-slip condition of the fluid in contact with a solid surface. With this article, the author wants to commemorate the bicentennial of the publication of "Sur les Lois du Mouvement des Fluides" by Navier in the Mémoires de l'Académie Royale des Sciences de l'Institut de France. [ABSTRACT FROM AUTHOR]

At high temperatures, the salt resistance of fluid loss agents is poor. In order to achieve the goal of high temperature salt resistance, a zwitterionic fluid loss agent was designed and synthesized.Using sodium p-styrene sulfonate, itaconic acid, acrylamide, and dimethyldiallylammonium chloride as raw materials, a water loss agent SMFD was synthesized through aqueous solution polymerization. The structural characterization of the polymer showed that the molecule contains the designed functional groups, has a moderate molecular weight, and can withstand heat at temperatures above 220 ℃. The microstructure of the polymer solution exhibits a three-dimensional network structure. The water loss of the 4% fluid loss additive at 150 °C is less than 50mL, and it still functions effectively in semi-saturated and saturated saline environments. Furthermore, the fluid loss addition has little effect on the strength, rheological properties, settlement stability, and other key features of the cement slurry, satisfying the necessary conditions for successful well cementing. The utilisation of microscopy, scanning electron microscopy, and organic carbon adsorption testing techniques revealed that the application of SMFD enhances the characteristics of cement filter cakes. This improvement is attributed to the formation of a polymer network through processes such as ion association, adsorption, and polymer synergy. The polymer network effectively fills the voids between cement particles, resulting in a more compact filter cake structure. Consequently, this leads to a reduction in water loss of the cement slurry. [ABSTRACT FROM AUTHOR]

Introduction: The mechanisms of catheter obstruction are still poorly understood, but the literature suggests that resistance to fluid flow plays a significant role. We developed and assessed a gravity-driven device that measures flow through ventricular catheters. We used this device to quantitatively analyze the resistances of unused ventricular catheters used in the treatment of hydrocephalus; failed hydrocephalus catheters from our catheter biorepository were also evaluated quantitatively. Methods: Catheters of three manufacturing companies were inserted into the benchtop model, which records time, flow rate, and pressure data using sensors. The relative resistances of catheters across six design models were evaluated. Experiments were performed to evaluate changes in the relative resistance of a catheter when the catheter's holes were progressively closed. The relative resistance of explanted catheters from our catheter biorepository was also measured. Results: Experimental results showed significant differences (P<0.05) between the relative resistances of different catheter models just after being removed from their packaging. A non-linear trend of increasing resistance was observed in experiments on catheters with artificially obstructed holes. Data from five individual benchtop models were compared, and the differences in measured data between the models were found to be negligible. A significant increase (P < 0.05) in relative resistance was observed in explanted catheters. Conclusion: The current study sought to propose a novel in-vitro model and use it to examine data on differences in relative resistance among catheter models. From these experiments, we can rapidly correlate clinical patient cohorts to identify mechanisms of luminal shunt obstruction. [ABSTRACT FROM AUTHOR]

Dual-gradient drilling technology is difficult to detect and deal with well kick, which may cause safety problems such as well control. Once a well kick occurs, the pressure in the narrow annulus increases instantaneously, so it is particularly important to clarify the transmission law of pressure wave. Taking the pressure fluctuation in the annulus of double gradient drilling as an example, considering the boundary between the inner wall of the casing annulus and the outer wall of the drill string, the fluid resistance, the flow field distribution and the multiphase flow, this paper deduces and establishes the multiphase flow pressure wave velocity model in the annulus, and compares the calculation results with the pressure wave velocity model in the circular pipe. The research shows that when the casing and drill string are in the static condition with small roughness and little difference between them, the shear stress on the inner wall of the annulus and the outer wall of the drill string can be treated as equal, and the derivation of the annulus pressure wave velocity model can be simplified. The pressure wave velocity of multiphase flow in annulus is related to casing size, drill string size and multiphase fluid properties. Among them, the gas content is the main influencing factor. With the increase of the gas content, the pressure wave velocity decreases, but the decreasing range will gradually decrease. When the solid content is small, it has little effect on the pressure wave velocity. [ABSTRACT FROM AUTHOR]

Techniques capable of producing small-sized probiotic microcapsules with high encapsulation yields are of industrial and scientific interest. In this study, an innovative membrane emulsification system was investigated in the production of microcapsules containing Lacticaseibacillus rhamnosus GG® (Lr), sodium alginate (ALG), and whey protein (WPI), rice protein (RPC), or pea protein (PPC) as encapsulating agents. The microcapsules were characterized by particle size distribution, optical microscopy, encapsulation yield, morphology, water activity, hygroscopicity, thermal properties, Fourier-transform infrared spectroscopy (FTIR), and probiotic survival during in vitro simulation of gastrointestinal conditions. The innovative encapsulation technique resulted in microcapsules with diameters varying between 18 and 29 μm, and encapsulation yields > 93%. Combining alginate and whey, rice, or pea protein improved encapsulation efficiency and thermal properties. The encapsulation provided resistance to gastrointestinal fluids, resulting in high probiotic viability at the end of the intestinal phase (> 7.18 log CFU g−1). The proposed encapsulation technology represents an attractive alternative to developing probiotic microcapsules for future food applications. [ABSTRACT FROM AUTHOR]

The structured scale surface is an important functional surface that reduces the drag resistance of fluids and contact friction resistance. In order to grind the bionic scale structure on the workpiece, based on the topological theory and the principle of grinding kinematics, a novel topological grinding strategy was proposed. To this end, the topological feature vectors of the structured scale surface and the grinding wheel surface were established by analyzing the biomimetic structured scale surface; The Topological space of grinding process is constructed and the topological mapping equation of grinding process is established; The feasibility of this grinding strategy was verified through simulation and grinding experiments. The research results indicate that the established topological mapping equation is correct; Under the condition of maintaining design parameters, the errors of the feature parameters of the ground structured scale surface are between 2.8% and 8%; As the grinding parameters change, the feature parameters of the ground scale surface will also change, but they can still maintain the same topological attributes as the designed scale surface. Therefore, the proposed topology grinding strategy is feasible. [ABSTRACT FROM AUTHOR]

In this paper, a novel heart valve model with parameters selections enabling to illustrate some physiological patterns such as healthy, aortic stenosis, and regurgitation has been shown. The motion of the elastic leaflet body is modeled by a nonlinear mass–spring–damper and coupled with a cardiovascular lumped parameter model. As a result, our model takes in to account a single continuous time-varying fluid resistance, the aortic flow rate, left ventricular and aortic pressures, and the leaflets' pose. This novel model is able to show the backflow, vortex and dicrotic notch phenomenon as approaching to the gold standard in physiological evaluation. The model also additionally presents reverse pressure effect on the aortic valve in the diastolic phase that is not observed in the recent literature. The physiological validation is performed by comparing two reference models and previously reported on physiological data. Nominal leaflet spring (α) and damping (c) parameters have been determined for the healthy valve (α = 0.1, c = 2), aortic stenosis (α = 0.005, c = 0.1), and aortic regurgitation (α = 0.001, c = 2). When compared to other studies, the left ventricular and aortic pressure, leaflets' opening-closing angles are generated in similar patterns. In addition, the reduction of the blood flow rate can now be observed in aortic regurgitation, which is not presented in the literature. In conclusion, a set of critical aortic valve conditions is parameterized by our novel model. The elastic structure of the leaflet model enabling us to demonstrate not only the vortex and dicrotic notch phenomenon but also the backflow and reverse pressure effect. Furthermore, it offers a generalized framework to realize extensive aortic valve conditions. [ABSTRACT FROM AUTHOR]

During the drilling process, cuttings settle under the action of gravity, which easily results in the formation of a cuttings bed, which then results in wellbore cleaning problems. The settling law of cuttings in drilling fluid is essentially a problem of solid–liquid two-phase settling. This study analyzes and summarizes the effects of the wall effect, the rheology of the fluid, particle shape irregularity, and particle concentration on the settling rate of particles and clarifies the problems faced by current research on the settling rate of particles and the development direction. Studies have shown that walls exert additional blocking effects on particles, thus reducing their settling velocity. The shear thinning effect of non-Newtonian fluids such as power-law fluids and Herschel–Bulkley fluids will reduce the viscosity of the liquid, thus increasing the settling velocity of the particles. Compared with spherical particles, irregular particles will obtain higher resistance in the fluid, leading to a decline in the particle settling velocity. The mutual interference between particles will result in an increase in the drag force on the particles and a decline in the settling velocity. However, when the particles are aggregated, the settling velocity will increase. This study can provide theoretical guidance for predicting the migration law of cuttings during the drilling of horizontal wells, and it has important significance for enriching the theory of solid–liquid two-phase flow. [ABSTRACT FROM AUTHOR]

Oil and gas reservoirs in volcanic rocks are a particular type of unconventional reservoir and present unique challenges for exploration and production engineers. To help the oil industry understand volcanic reservoirs and solutions to complex development problems, we reviewed their key engineering technologies as well as their geological characteristics. The distinctive geological characteristics of volcanic hydrocarbon reservoirs are strong heterogeneity, low porosity and permeability, complex fracture systems, etc. The volcanic reservoir rock types in order of hydrocarbon abundance are basalt (38.5%), andesite (15.9%), volcaniclastic (12.1%), and rhyolite (11.5%). The porosity ranges from 0.1 to 70%, and permeability ranges from 0.0007 to 762 md. In some commercially developed volcanic reservoirs of China, the average porosity is 7.7–13%; the average permeability is 0.41–3.4 md. Engineers have applied a variety of adapted technologies to produce volcanic reservoir economically. Horizontal wells can increase production and reserves by 4–6 times those of vertical wells, and longer wells are preferred. Specialized hydraulic fracturing techniques are suggested, including small or mixed proppant size, second HF treatment after proppant slugging, high-viscosity frac fluid with high-temperature resistance, special fluid loss reducer, high pump pressure, Extreme Overbalance Perforating, limited-entry fracturing, matrix acidizing, etc. Water control measures include producing below critical rates, partial perforation or penetration, controlling hydraulic fracture height, using horizontal wells, implementing complete cementing job, etc. Well productivity evaluation should be conducted to understand well performance and appropriately allocate production rates among wells, using the modified AOF method and other productivity prediction models considering breakdown fracture gradient, gas slippage effect, non-Darcy effect, etc. Well sites need to be selected based on recognizing profitable lithologies, lithofacies, high porosity and permeability, relatively developed fracture systems, thick net pay zones, etc. The critical questions for the industry are how to enhance volcanic reservoir recovery with more efficient and economic hydraulic fracturing and water control techniques. This is one of the first papers systematically summarizing the engineering technologies and unique solutions to develop volcanic reservoirs. Further and more complete reviews can be carried out in the future, and more novel and effective techniques can be explored and tested in the field. [ABSTRACT FROM AUTHOR]

Employing a combination of Polyethylene terephthalate (PET) thermoforming and 3D-printed cylindrical patterns, we carefully engineer a linear resistive temperature sensor. This intricate process involves initial PET thermoforming, yielding a hollow cylindrical chamber. This chamber is then precisely infused with a composite fluid of graphite and water glue. Ensuring electrical connectivity, both ends are affixed with metal wires and securely sealed using a hot gun. This cost-effective, versatile sensor adeptly gauges temperature shifts by assessing composite fluid resistance alterations. Its PET outer surface grants immunity to water and solubility concerns, enabling application in aquatic and aerial settings without extra encapsulation. Rigorous testing reveals the sensor's linearity and stability within a 10 °C to 60 °C range, whether submerged or airborne. Beyond 65 °C, plastic deformation arises. To mitigate hysteresis, a 58 °C operational limit is recommended. Examining fluidic composite width and length effects, we ascertain a 12 Ω/°C sensitivity for these linear sensors, a hallmark of their precision. Impressive response and recovery times of 4 and 8 s, respectively, highlight their efficiency. These findings endorse thermoforming's potential for fabricating advanced temperature sensors. This cost-effective approach's adaptability underscores its viability for diverse applications. [ABSTRACT FROM AUTHOR]