Fluid Behavior Research Articles

Experimental study of influence of temperature, salt, and pH on the rheological behavior of eco-friendly water-based drilling fluid

Experimental study of influence of temperature, salt, and pH on the rheological behavior of eco-friendly water-based drilling fluid

Unified Pressure, Surface Tension and Friction for SPH Fluids

Fluid droplets behave significantly different from larger fluid bodies. At smaller scales, surface tension and friction between fluids and the boundary play an essential role and are even able to counteract gravitational forces. There are quite a few existing approaches that model surface tension forces within an SPH environment. However, as often as not, physical correctness and simulation stability are still major concerns with many surface tension formulations. We propose a new approach to compute surface tension that is both robust and produces the right amount of surface tension. Conversely, less attention was given to friction forces at the fluid-boundary interface. Recent experimental research indicates that Coulomb friction can be used to describe the behavior of droplets resting on a slope. Motivated by this, we develop a novel friction force formulation at the fluid-boundary interface following the Coulomb model, which allows us to replicate a new range of well known fluid behavior such as the motion of rain droplets on a window pane. Both forces are combined with an IISPH variant into one unified solver that is able to simultaneously compute strongly coupled surface tension, friction and pressure forces.

Experimental Investigation of the Impact of Mixed Wettability on Pore-Scale Fluid Displacement: A Microfluidic Study.

Understanding rock wettability is crucial across various fields including hydrology, subsurface fluid storage and extraction, and environmental sciences. In natural subsurface formations like carbonate and shale, mixed wettability is frequently observed, characterized by heterogeneous regions at the pore scale that exhibit both hydrophilic (water-wet) and hydrophobic (oil-wet) characteristics. Despite its common occurrence, the impact of mixed wettability on immiscible fluid displacement at the pore scale remains poorly understood, creating a gap in effective modeling and prediction of fluid behavior in porous media. The primary objective of this study was to investigate how mixed wettability affects pore-scale fluid displacement dynamics, utilizing microfluidic devices designed to replicate rock-like structures with varied wettability properties. Current techniques for achieving mixed wettability within microfluidic devices often struggle with spatial control and resolution, limiting their accuracy. To address this limitation, a novel approach was employed that combined photolithography and molecular vapor deposition of perfluorodecyltrichlorosilane to precisely and selectively modify wettability within specific pore regions, achieving a mixed wettability distribution correlated with pore size for the first time. The experimental setup included five identical micromodels representing distinct wetting conditions, which were initially saturated with air and subsequently flooded by water. By systematically varying the ratio of hydrophilic to hydrophobic areas, we covered a range from fully hydrophilic to fully hydrophobic and intermediate mixed wettability configurations. Comparative displacement experiments revealed that pore-level mixed wettability has a pronounced effect on fluid displacement behavior, influencing the injection time, spatial invasion patterns, and dynamic pressure profiles. Results indicated that both the injection time and dynamic pressure decreased with an increase in the hydrophilic area fraction. Each wettability configuration displayed unique sequences of pore-filling events, emphasizing the critical role of the wettability distribution in influencing displacement dynamics. While mixed wettability exhibited a clear monotonic effect on invasion time and dynamic pressure, saturation behavior was notably nonmonotonic. Interestingly, mixed wettability scenarios with relatively medium to high hydrophilic fractions demonstrated enhanced overall sweep efficiency compared to the hydrophobic case and reduced the bypassed gas phase relative to the hydrophilic case. However, inefficiently distributed mixed wet zones were found to reduce the sweep efficiency. These findings highlight the critical influence of mixed wettability in fluid displacement processes, with significant implications for applications in oil recovery, CO2 sequestration, and other subsurface energy technologies.

Rheo-SINDy: Finding a constitutive model from rheological data for complex fluids using sparse identification for nonlinear dynamics

Rheology plays a pivotal role in understanding the flow behavior of fluids by discovering governing equations that relate deformation and stress, known as constitutive equations. Despite the importance of these equations, current methods for deriving them lack a systematic methodology, often relying on sense of physics and incurring substantial costs. To overcome this problem, we propose a novel method named Rheo-SINDy, which employs the sparse identification of nonlinear dynamics (SINDy) algorithm for discovering constitutive models from rheological data. Rheo-SINDy was applied to five distinct scenarios, four with well-established constitutive equations, and one without predefined equations. Our results demonstrate that Rheo-SINDy successfully identified accurate models for the known constitutive equations and derived physically plausible approximate models for the scenario without established equations. Notably, the identified approximate models can accurately reproduce nonlinear shear rheological properties, especially at steady state, including shear thinning. These findings validate the availability of Rheo-SINDy in handling data complexities and underscore its potential for advancing the development of data-driven approaches in rheology. Nevertheless, further refinement of learning strategies is essential for enhancing robustness to fully account for the complexities of real-world rheological data.

Machine learning-driven predictive modeling of magnetohydrodynamic double diffusion of non-Newtonian hybrid ferrofluids with variable thermophysical properties within corrugated cylinders

This study addresses the complex problem of magnetohydrodynamic (MHD) double diffusion in non-Newtonian hybrid ferrofluids within a concentric corrugated cylinder. Understanding this phenomenon is crucial due to its applications in advanced cooling systems, biomedical drug delivery, and industrial processes where precise control of fluid dynamics and heat transfer is essential. Traditional simulations face challenges in capturing these complexities accurately, making it imperative to explore more efficient modeling approaches. To overcome these challenges, we employed a computational fluid dynamics (CFD) framework combined with machine learning predictive modeling. Four machine learning algorithms – decision tree regression (DT), random forest regression (RF), feed-forward neural networks (FFNN), and 1-dimensional convolutional neural networks (1D-CNN) – were used to analyze the behavior of the fluid under various conditions. The CFD simulations revealed that increasing the power law index (n) results in a decrease in flow rates, with a 20.53% reduction for n from 0.8 to 1 and a 49.04% reduction for n from 1 to 1.4. Significant variations in volume fraction (ϕ) and Hartmann number (Ha) were observed to affect average Nusselt number (Nu¯) and Sherwood number (Sh¯). The machine learning models demonstrated high predictive accuracy, with 1D-CNN achieving R2 values of 0.9996, 0.9994, and 0.9995 for Nu¯, Sh¯, and |Ψ|, respectively. The FFNN achieved R2 values of 0.9995, 0.9984, and 0.9995 for the same metrics. These results confirm that the studied parameters-Rayleigh number (Ra), Hartmann number (Ha), and power law index (n)-significantly influence flow properties. The novelty of this work lies in the integration of machine learning techniques with CFD simulations to model MHD double diffusion in non-Newtonian hybrid ferrofluids. This approach provides a more precise and resource-efficient method for analyzing complex fluid behaviors compared to traditional simulation methods. The findings have significant implications for various applications, including energy systems, biomedical engineering, industrial cooling, and chemical processing. The study not only advances the understanding of MHD phenomena in non-Newtonian fluids but also offers practical insights for designing improved cooling systems and other applications where precise fluid control is essential.

Demonstration of Energy Loss Due to Specific Plumbing Variables, in the Hydraulics Laboratory, of UMA (SDG)

Objective: This study investigates energy losses in various pipe fittings such as bends, contractions, enlargements, and control valves, with the goal of determining the loss coefficients for each fitting. The aim is to analyze pressure drops across different fittings and evaluate how these energy losses influence the design and efficiency of hydraulic systems. Theoretical Framework: The experiment is grounded in fluid dynamics, focusing on the principles of Bernoulli’s equation, pressure drops, and the impact of various pipe fittings on energy loss in hydraulic systems. The Reynolds number, as a dimensionless measure of inertial to viscous forces, is also considered in understanding flow behavior and energy dissipation during fluid movement through pipes. Method: The research employs the F1-22 Energy Losses in Bends and Fittings apparatus attached to a hydraulic bench. Pressure drops are measured across the pipe fittings using a series of water manometer tubes, and the flow rate is controlled by a gate valve. The procedure includes recording piezometric head readings, volume, and drainage velocity to calculate the loss coefficients for each fitting. Results and Discussion: The experiment’s results reveal significant variations in energy losses across different fittings. These findings highlight the influence of fitting configurations on fluid flow and energy efficiency. The loss coefficients derived from the data provide insights into the factors that contribute to energy dissipation, helping engineers optimize hydraulic system designs. Research Implications: The study’s results are critical for optimizing the selection and design of hydraulic fittings. By understanding energy losses, engineers can design more energy-efficient systems, reducing overall operational costs and enhancing the sustainability of hydraulic infrastructure. Originality/Value: This research contributes new empirical data on energy losses in hydraulic systems, offering a deeper understanding of fluid behavior in different pipe configurations. The findings are valuable for improving the design of energy-efficient and sustainable hydraulic systems, particularly in industrial applications.

Combined Impacts of Thermal and Mass Stratification on Unsteady MHD Parabolic Flow Along an Infinite Vertical Plate With Periodic Temperature Variation and Variable Mass Diffusion

ABSTRACTThis study investigates the dynamics of unsteady MHD parabolic flow along an infinite vertical plate, with a focus on the impacts of thermal and mass stratification under periodic temperature variations and variable mass diffusion. Utilizing the Laplace transform technique for deriving exact solutions, this research innovatively integrates both thermal and mass stratification effects without resorting to approximations. The main objective is to assess how these stratifications influence flow dynamics, temperature, and concentration profiles in environments with varying magnetic fields. The study contrasts these findings against classical non‐stratification cases, offering a detailed comparison of fluid behavior under different conditions. Results indicate that thermal and mass stratifications substantially decrease velocity and stabilize temperature profiles, pointing to a damping effect on fluid motion while also controlling diffusion processes. These stratifications lead to higher Nusselt and Sherwood numbers, suggesting improved heat and mass transfer efficiencies. In contrast, the absence of stratification results in higher velocities and less stable temperature and concentration distributions. The findings underscore the significant role of stratification in optimizing fluid dynamics and enhancing the efficiency of heat and mass transfer processes, providing crucial insights for engineering and environmental applications where such conditions prevail.

Effect of Magnetic Field and Slip Conditions on Flow in a Rotating Porous Channel With Viscous Dissipation

ABSTRACTThis study examines the steady flow of an electrically conducting fluid through a rotating porous channel bounded by stationary, impermeable horizontal plates at constant temperature. The primary aim is to explore the combined effects of a magnetic field, wall slip conditions, and viscous dissipation. The channel rotates at a constant angular velocity, with slip conditions applied at the walls. A pressure gradient drives the primary flow, while rotation generates the secondary flow. Analytical solutions for velocity profiles and volumetric flow rates are obtained, and the temperature distribution is calculated using MATLAB's “bvp4c” function. The research offers novel insights into the behavior of primary and secondary flow velocities under different Hartmann and Taylor numbers, emphasizing the impact of slip conditions. Additionally, the influence of the Eckert number on temperature is analyzed in conjunction with these parameters. These findings contribute valuable theoretical perspectives for enhancing cooling systems in rotating machinery using conductive fluids in porous channels. This study opens avenues for future research to investigate unsteady flow conditions and the effects of variable magnetic fields and rotational speeds on fluid behavior in rotating porous channels.

A model for predicting temperature and pressure profiles in gas-lifted oil wells

This work presents a methodology for predicting temperature and pressure profiles in oil wells that employ the artificial lift technique through gas-lift. When the reservoir pressure is not sufficient to bring the oil to the surface or when increasing production efficiency is desired, artificial lift techniques are employed. The injection of gas (gas-lift) is one of the most commonly used techniques. In the oil and gas industry, the accurate prediction of temperature profiles during various operations is crucial for ensuring well integrity. These profiles serve as inputs for calculating variations in annular pressures, casing stress, corrosion rates, and other critical parameters. However, calculating these profiles is challenging, requiring data on the well's underground structure, simultaneous resolution of the differential equations governing heat transfer phenomena in the structure, and modeling the hydrodynamic behavior of fluids. In wells where production operations are carried out using gas-lift, the complexity is even greater because the annular fluid, previously static, now circulates downward. This fact increases the number of equations to be solved and the number of fluids to be modeled. Thus, the development of strategies for obtaining these profiles is justified. To achieve the proposed objective, the methodology adopted in this work is based on three main steps: a) description of the mathematical formulation of the problem, considering the energy, momentum, and mass balance in the flow of both the produced fluid and the injected fluid; b) development of a numerical strategy enabling the simultaneous solution of the equations formulated in the previous step, thus allowing the determination of temperature and pressure profiles in the well; and c) verification of the strategy by comparing the results obtained using the procedure described in this work with thermal profiles from wells reported in the literature. The main contribution of this work is to enable the prediction of thermal profiles in oil wells in production operations with artificial lift by gas injection, allowing these profiles to be used in the design and monitoring of wells, thereby adding safety and efficiency to the operation.

Assessment of Strategies for Numerical Modeling of the APB in Oil Wells

This study aims to study and compare numerical modeling strategies for reproducing the phenomenon of Annular Pressure Build-up (APB) in vertical oil wells, in order to contribute to the development of procedures with higher accuracies. APB occurs due to the tendency of confined fluids filling the annular region between casings to expand in response to thermal variations within the well. This phenomenon is critical in the petroleum industry, especially in deepwater environments, where greater temperature and pressure differentials are present. APB leads to increased stresses on well casings, which can cause structural failures and, in extreme situations, could in human, environmental, and economic losses. Therefore, studying the origins and effects of this phenomenon and considering them during the well design phase are essential to ensure safety and efficiency. Motivated by the significance of the topic and the challenge of reproducing APB analytically, several authors have sought to model the phenomenon and its effects using finite element-based computational software like Abaqus. To achieve the proposed objective, the methodology adopted includes: a) literature review of existing strategies for APB modeling; b) definition of a simplified scenario for reproducing selected strategies; c) comparison of methodologies and results obtained from each; and d) discussion on discrepancies, gaps, and potential improvement opportunities. This study evaluates two modeling strategies in Abaqus, both utilizing fluid cavity interaction to model fluid behavior within a plane axisymmetric analysis. The difference lies in the approach to thermal expansion. While one calculates APB directly from thermal variation, the other does so by introducing an equivalent mass flow. Furthermore, the strategies will be compared not only in terms of results and accuracy, but also with regards to computational cost, aiming to identify the most efficient approach for modeling the phenomenon. Despite methodological differences, both approaches yield similar results, with the second providing the flexibility to model fluids with different behaviors. Thus, this study contributes to understanding and optimizing APB modeling, aiding in the development of more robust and efficient strategies for predicting the effects of this phenomenon.

Three-Dimensional Pulsating Flow Simulation in a Multi-Point Gas Admission Valve for Large-Bore CNG Engines

This study examines the dynamic fluid behavior of a PWM-controlled Solenoid-Operated Gas Admission Valve (SOGAV) for large-bore CNG engines using 3D Computational Fluid Dynamics (CFD) simulations with dynamic mesh techniques. The research focuses on the influence of orifice geometry variations in the multi-hole restrictor and pressure differentials between the inlet and outlet on flow stability, turbulence, and valve performance. Results demonstrate that multi-hole restrictors with different-sized orifices improve flow uniformity and reduce turbulence, thereby mitigating flow resistance. Transient simulations further reveal standing wave formation and pressure wave interference, emphasizing that steady-state models cannot capture critical transient phenomena, such as accelerated and decelerated jet-like flows and flow separation. These findings provide key insights into SOGAV optimization, contributing to enhanced fuel efficiency and engine responsiveness, meeting the performance requirements of modern gas engines.

Evaluation of the Impact of Mineralogy On Oil Recovery Using Digital Petrophysics

Exploring pre-salt oil deposits poses a significant challenge for the oil and gas industry. Carbonate rock reservoirs, being more susceptible to diagenetic actions, exhibit considerable complexity due to the heterogeneity of the porous system, making exploration activities in this scenario challenging. Microscale analysis of fluid behavior in porous media from X-ray microtomography images and petrophysical system analyses has become increasingly essential for enhancing techniques applied in this sector. To investigate the impact of mineralogy on oil recovery using desulfated seawater (DSW), two samples of coquinas from the Morro do Chaves Formation, Sergipe-Alagoas Basin, considered analogs to the coquinas of the Itapema Formation in the Santos Basin, Brazilian pre-salt, were utilized. Due to the depositional context of this formation, the coquinas from the Morro do Chaves Formation contain terrigenous minerals, primarily quartz, in their composition. This study aims to understand how different percentages of these terrigenous minerals associated with carbonate minerals can influence reservoir oil recovery. For this purpose, 3D image analyses obtained by micro-CT at different saturation phases: dry, water-saturated formation, oil-aged, and at various contact times with DSW were employed. To confirm observations acquired through images, the contact angle of the system was measured, where samples aged in oil came into contact with recovery water. Image analyses were conducted using profiles of both porosity and fluid saturation present in the pores. As a result, indications were observed that terrigenous minerals influence rock wettability. The sample containing higher percentages of these minerals demonstrated an affinity with oil, while the other, lacking these minerals, exhibited water-wettability. Different interpretations, however, could be identified: desulfated seawater did not benefit oil recovery, as the sample with a high content of terrigenous material showed the highest efficiency in removing residual oil; another interesting aspect found in this sample was the tendency for gas entrapment, as the percentage of pores filled with air remained practically constant during the process.

Direct simulations of bedrock core and cuttings transport phenomena in reverse circulation drilling

Polar drilling is essential for obtaining ice and bedrock samples, providing critical insights into climate and geological history. The reverse circulation drilling method, utilizing a dual-wall drill pipe, presents a stable and efficient strategy. Nonetheless, the intricate dynamics involving drilling fluids, rock cuttings and cores necessitate sophisticated modeling to elucidate the underlying mechanism and optimize drilling efficiency. To address this, we developed a multiphase flow model that accounts for non-Newtonian fluid behavior, turbulence, particle dynamics, and fluid–structure interactions, enabling a thorough assessment of various operational parameters. The model's temporal–spatial sensitivity was evaluated, and its accuracy was confirmed by comparison with three different sets of experimental data. A detailed parametric investigation was then conducted to systematically assess the effects of various parameters, including the non-Newtonian behavior and inlet velocity of the drilling fluid, the rate of penetration, and the dimensions of the cuttings and core. The simulation results indicate that the non-Newtonian behavior of the drilling fluid has an non-negligible effect on the transport efficiency of both cuttings and core. An increase in the fluid inlet velocity leads to faster transport, albeit at the cost of higher pump pressure. The rate of penetration has a minor influence on the core transportation but largely affects the cutting transportation. More interestingly, larger cuttings demonstrate enhanced transport efficiency, attributed to a more uniform velocity distribution. Furthermore, the core diameter plays a pivotal role in transport efficiency by significantly altering the fluid dynamics, whereas the core length has a negligible effect. These results may have direct applications for optimizing polar drilling operations, potentially leading to enhanced drilling efficiency, reduced drilling costs, and informing future drilling technology advancements.

Rheological characterization and modeling of ultra-high-velocity fluidized submarine landslides

Submarine landslides are critical phenomena due to their potential to reshape seabed topography, trigger tsunamis, and compromise offshore infrastructure. Understanding the rheological properties, particularly shear stress and viscosity under high shear rates, is essential for comprehending the dynamics of these landslides, a topic often underexplored in previous research. This study explores the rheological behavior of fluidized submarine landslides, with a focus on in-site sediments from the South China Sea and the Western Pacific Ocean. Samples prepared with varying densities were subjected to extensive rheological testing in the laboratory and analyzed under shear rates of up to 2000 s−1. Results indicated that all samples exhibited non-Newtonian fluid characteristics, showing shear-thinning behavior at low shear rates and shear-thickening behavior at higher shear rates. This transition is attributed to the breakdown of internal sediment structures, leading to changes in viscosity. This study also found that higher water content generally results in lower yield stress and consistency coefficients, while increasing the shear rate reduces the nonlinearity of the fluid's behavior. To model this complex behavior, a piecewise rheological model based on the Herschel-Bulkley framework was proposed. This model effectively captures the variations in rheological properties across different shear rate stages, with critical shear rates influenced by the sediment type and water content. These findings contribute to a deeper understanding of submarine landslides under extreme conditions, and the proposed model offers a more accurate tool for predicting the behavior of fluidized submarine landslides.

Investigating the influence of magnetic field on heat transfer in turbulent ferromagnetic fluid over a backward-facing step

In this research, we present a computational investigation into the behavior of turbulent ferromagnetic fluids flowing over a backward-facing step, influenced by an external magnetic field. Our model is subjected to a rigorous validation process to prevent error masking across various submodels. The study encompasses a range of Reynolds numbers (ReH) from 5000 to 80 000, expansion ratios (Er) from just above 1 to 2, Prandtl numbers (Pr) from 4 to 8, and Hartmann numbers (Ha) from 0 to 100. We introduce innovative correlations for the average Nusselt number, applicable in both the presence and absence of a magnetic field. These novel correlations are meticulously compared with existing empirical formulas, and their compatibility and discrepancies are critically analyzed. By incorporating a broader spectrum of physical phenomena, such as the braking effect of magnetohydrodynamics, the impact of the step geometry, the resulting recirculation zones, and the potential inaccuracies in calculating average velocity and Reynolds number, our new correlations substantially enhance the predictive accuracy of the average Nusselt number compared to previous models.

Rheology of polyacrylamide-based fluids and its impact on proppant transport in hydraulic fractures

Rheological experiments and measurements of particle settling velocity under static conditions were conducted for two types of polyacrylamide (PAA-based) fluids. The flow behavior of the viscoelastic fluids is described by a simplified, three-parameter model that integrates a constant viscosity at low shear rates with a power-law viscosity dependency at higher shear rates. The estimated dependencies of the rheological parameters and particle settling velocity on PAA concentration align with the classical power-law scaling for semi-dilute polymer solutions. The identified scaling offers valuable insight for optimizing the chemical composition of fracturing fluids, thereby improving the efficiency of hydraulic fracturing technology. By applying the lubrication approximation to the Navier–Stokes equations, a set of equations for the suspension flow in a vertical plane channel, characterized by the three-parameter rheology model, was derived. In typical fracturing conditions, the conventional power-law viscosity model used in current fracturing simulators significantly overestimates the gap-averaged apparent fluid viscosity compared to the proposed model. The novel model of the suspension flow aims to enhance the accuracy of proppant transport models applied in hydraulic fracturing simulators. Based on the three-parameter rheology model, a new model of particle settling in the studied PAA-based fluids is developed. It is based on smart Stokes' law, where viscosity is calculated according to either the plateau or power-law region, depending on the self-induced shear rate. The new model more accurately approximates experimentally determined settling velocity of proppant under static conditions across a broad range of PAA concentrations than existing models.

First hydrodynamic instability and flow transitions between concentric vertical cylinders

This comparative experimental and numerical study investigates the first hydrodynamic instability and flow transitions in the annular gap between concentric vertical cylinders, with the inner cylinder rotating and the outer cylinder stationary. The study contrasts the behavior of a non-Newtonian fluid, carboxymethyl cellulose (CMC), with that of a Newtonian fluid, potassium sulfate (K2SO4). The influence of inner cylinder rotational speed, represented by Reynolds (Re) and Taylor (Ta) numbers, and filling rates (Γ) on the first instability thresholds and flow modes is examined for both fluids. Experimental visualization and numerical simulations illustrate distinct flow characteristics, emphasizing the significant impact of CMC's non-Newtonian properties on flow structure formation and instability thresholds. Rheological analysis identifies instability thresholds specific to CMC at a 0.2% concentration. The study further analyzes azimuthal and axial wave numbers (n) and (λ) relative to Reynolds number (Re) and filling rates (Γ) to characterize flow dynamics comprehensively.

Investigation of the microstructural characteristics of laser-cladded Ti6Al4V titanium alloy and its corrosion behavior in simulated body fluid

Laser cladding technology has a wide range of potential industrial applications in the surface strengthening, repair and reuse of orthopedic implants. By employing this technique to conduct same-material surface restoration and enhancement on titanium alloys, it demonstrates significant developmental potential. However, the microstructure of laser additively manufactured titanium alloy differs significantly from that of traditional titanium alloys, which affects its corrosion resistance in human body fluids. To compare the corrosion resistance differences between the cladding layer and the substrate, this study investigates the microstructure of multi-pass laser cladding Ti6Al4V (TC4) titanium alloy and analyzes the corrosion morphology and corrosion products of the cladding layer in simulated body fluids (SBF). By comparing the electrochemical corrosion behavior of laser cladding with that of traditionally manufactured TC4, this research reveals the differences in corrosion resistance between the two titanium alloys. The research demonstrates that the microstructure of cladding primarily consists of prior-β grains and continuous grain boundary α phase, along with a complex basketweave structure composed of fine acicular α phase and lamellar α phase. Additionally, due to the complex thermal cycling process, the acicular α' colonies within the prior-β grains. These features enhance the cladding layer’s resistance to plastic deformation and increase microhardness, though with some uneven distribution. Interestingly, the TC4 cladding layer forms a porous passivation layer after corrosion, primarily composed of a TiO2 passivation film and deposits of hydroxyapatite and other phosphates. Due to the lower β-phase content, finer grains with higher energy states, and a greater proportion of high-angle grain boundaries (HAGBs) in the cladding layer, it exhibits higher electrochemical activity. As a result of these microstructural differences, the corrosion resistance of the TC4 cladding layer in SBF is inferior to that of TC4 manufactured using traditional techniques.

Customizable Microfluidic Devices: Progress, Constraints, and Future Advances.

The field of microfluidics encompasses the study of fluid behavior within micro-channels and the development of miniature systems featuring internal compartments or passageways tailored for fluid control and manipulation. Microfluidic devices capitalize on the unique chemical and physical properties exhibited by fluids at the microscopic scale. In contrast to their larger counterparts, microfluidic systems offer a multitude of advantages. Their implementation facilitates the investigation and utilization of reduced sample, solvent, and reagent volumes, thus yielding decreased operational expenses. Owing to their compact dimensions, these devices allow for the concurrent execution of multiple procedures, leading to expedited experimental timelines. Over the past two decades, microfluidics has undergone remarkable advancements, evolving into a multifaceted discipline. Subfields such as organ-on-a-chip and paper-based microfluidics have matured into distinct fields of study. Nonetheless, while scientific progress within the microfluidics realm has been notable, its translation into autonomous end-user applications remains a frontier to be fully explored. This paper sets forth the central objective of scrutinizing the present research paradigm, prevailing limitations, and potential prospects of customizable microfluidic devices. Our inquiry revolves around the latest strides achieved, prevailing constraints, and conceivable trajectories for adaptable microfluidic technologies. We meticulously delineate existing iterations of microfluidic systems, elucidate their operational principles, deliberate upon encountered limitations, and provide a visionary outlook toward the future trajectory of microfluidic advancements. In summation, this work endeavors to shed light on the current state of microfluidic systems, underscore their operative intricacies, address incumbent challenges, and unveil promising pathways that chart the course toward the next frontier of microfluidic innovation.

Optimizing Microfluidic Channel Design with High-Performance Materials for Safe Neonatal Drug Delivery.

Designing the microfluidic channel for neonatal drug delivery requires proper considerations to enhance the efficiency and safety of drug substances when used in neonates. Thus, this research aims to evaluate high-performance materials and optimize the channel design by modeling and simulation using COMSOL multiphysics in order to deliver an optimum flow rate between 0. 3 and 1 mL/hr. Some of the materials used in the study included PDMS, glass, COC, PMMA, PC, TPE, and hydrogels, and the evaluation criterion involved biocompatibility, mechanical properties, chemical resistance, and ease of fabrication. The simulation was carried out in the COMSOL multiphysics platform and demonstrated the fog fluid behavior in different channel geometries, including laminar flow and turbulence. The study then used systematic changes in design parameters with the aim of establishing the best implementation models that can improve the efficiency and reliability of the drug delivery system. The comparison was based mostly on each material and its appropriateness in microfluidic usage, primarily in neonatal drug delivery. The biocompatibility of the developed materials was verified using the literature analysis and adherence to the ISO 10993 standard, thus providing safety for the use of neonatal devices. Tensile strength was included to check the strength of each material to withstand its operation conditions. Chemical resistance was also tested in order to determine the compatibility of the materials with various drugs, and the possibility of fabrication was also taken into consideration to identify appropriate materials that could be used in the rapid manufacturing of the product. The results we obtained show that PDMS, due to its flexibility and simplicity in simulation coupled with more efficient channel designs which have been extracted from COMSOL, present a feasible solution to neonatal drug delivery. The present comparative study serves as a guide on the choice of materials and design of microfluidic devices to help achieve safer and enhanced drug delivery systems suitable for the delicate reception of fragile neonates.