Reduction In Velocity Research Articles

Slowing Down a Coherent Superposition of Circular Rydberg States of Strontium.

Rydberg alkaline earth atoms are promising tools for quantum simulation and metrology. When one of the two valence electrons is promoted to long-lived circular states, the second valence electron can be optically manipulated without significant autoionization. We harness this feature to demonstrate laser slowing of a thermal atomic beam of circular strontium atoms. By driving the main ion core 422nm wavelength resonance, we observe a velocity reduction of 50 m/s without significant autoionization. We also show that a superposition of circular states undergoes very weak decoherence during the cooling process, up to the scattering of more than 1000 photons. This robustness opens new perspectives for quantum simulations over long timescales with circular atoms, while simultaneously cooling their motional state. It makes it possible to mitigate the harmful effects of unavoidable heating due to spin-motion coupling during a quantum simulation.

Exploring the influence of flexural rigidity variability of aquatic plants on stem deflection geometry and flow characteristics

The existing assumption of a constant flexural rigidity (EI) for the entire height of aquatic plants in the analysis of flow past flexible vegetation may not translate in to real scenario as EI of a flexible plant stem varies along the height due to variation in tissue structure and cross section. This variation is therefore needed to be effectively quantified for better analysis of flow-vegetation interaction. In this regard, the own-weight cantilever method was used to represent the variability of EI along the stem height of three plants: water lily, water chestnut, and lotus. Analytical models are proposed to predict stem deflection geometry and vertical velocity distribution across channel depth incorporating EI as a function of stem height. Analytical and experimental data, obtained from open-channel flume tests, significantly support the developed models and confirm the assumption of variable flexural rigidity. Further investigations show that the flexural rigidity, transcends being a mere constant numeric value; it profoundly influences various aspects of the fluid-vegetation interaction such as: the extent of deflection geometry, velocity reduction, Reynold stress variation, and penetration length. Therefore, this study is crucial for better understanding of the physics of sediment transport, pollutant mixing, and wetland management and restoration.

The effect of initial pressure and temperature on the flow in a three-dimensional cavity filled with paraffin/Cu nanostructure with a wavy lower wall and a movable upper wall using molecular dynamics simulation

Phase change materials (PCMs) are very suitable for the storage of thermal energy. Heat transfer plays a crucial role in many important industrial processes in today's industrial environment. Thus, it is crucial to examine and comprehend this occurrence properly. This work uses molecular dynamic simulation to examine the effect of initial pressure (IP) and temperature (Temp) on the thermal efficiency of phase change materials inside a three-dimensional cavity. The hollow contains paraffin/Cu nanoparticles and has a bottom wall with a wavy shape and an upper wall that can be adjusted. The results of the equilibration stage indicated that the kinetic and potential energies converge to 2100 eV and -95472.50 eV after 10 ns. Next, the results show that increasing IP resulted in the reduction of maximum velocity and Temp, which decreased from 0.0099 Å/ps and 898 K to 0.0090 Å/ps and 888 K. Furthermore, the results show that by increasing IP, the heat flux and thermal conductivity decrease from 9.95 W/m2 and 1.45 W/m.K to 8.89 W/m2 and 1.26 W/m.K. Conversely, as the initial Temp rose from 300 to 350 K, so did the velocity (0.0125 Å/ps) and Temp (990 K). Furthermore, the thermal conductivity and heat flux increased to 1.69 W/mK and 11.25 W/m2, respectively. This study reveals how molecular dynamics simulations provide insights into the effects of initial pressure and temperature on the flow and thermal behavior of a paraffin/copper nanostructure. The findings improve understanding of nanofluid and phase change material behavior, aiding the design of more efficient PCM-based systems for thermal energy storage and heat transfer applications. In general, the results of this research illuminate the complex relationship among IP, Temp, and thermal properties of phase change materials. This knowledge is of great significance as it can guide the formulation of novel approaches to enhance the thermal efficiency of these materials in practical applications.

Acute effects of lower limb wearable resistance on horizontal deceleration and change of direction biomechanics.

This study aimed to investigate the acute effects of lower limb wearable resistance on maximal horizontal deceleration biomechanics, across two different assessments. Twenty recreationally trained team sport athletes performed acceleration to deceleration assessments (ADA), and 5-0-5 change of direction (COD) tests across three load conditions (unloaded, 2% of BW, 4% of body weight (BW)), with load attached to the anterior and posterior thighs and shanks. Linear mixed effect models with participant ID as the random effect, and load condition as the fixed effect were used to study load-specific biomechanical differences in deceleration mechanics across both tests. Primary study findings indicate that for the ADA, in the 4% BW condition, participants exhibited significantly greater degrees of Avg Approach Momentum, as well as significant reductions in deceleration phase center of mass (COM) drop, and Avg Brake Step ground contact deceleration (GCD) in both the 2% BW, and 4% BW condition, compared to the unloaded condition. In the 5-0-5 tests, participants experienced significant reductions in Avg Approach Velocity, Avg deceleration (DEC), and Stopping Time in the 4% BW condition compared to the unloaded condition. Similar to the ADA test, participants also experienced significant reductions in Avg Brake Step GCD in both the 2% BW and 4% BW conditions, and significant increases in Avg Approach Momentum in the 4% BW condition, compared to the unloaded condition. Therefore, findings suggest that based on the test, and metric of interest, the addition of lower limb wearable resistance led to acute differences in maximal horizontal deceleration biomechanics. However, future investigations are warranted to further explore if the use of lower limb wearable resistance could present as an effective training tool in enhancing athlete's horizontal deceleration and change of direction performance.

Smaller Left Ventricular Size But Preserved Function in Adolescents and Adults Born Preterm.

Prematurely born adults have increased risk for cardiovascular disease. There are limited cardiac data on US-born preterm individuals. We aimed to determine whether adolescents and adults born prematurely have altered left ventricular (LV) structure and function, and to interrogate diastolic function using isometric handgrip exercise. Adolescents and adults born moderately to extremely preterm (≤32 weeks gestation or <1500 g birth weight) were recruited from the Parkland Health Neonatal Intensive Care Unit Registry. Full-term participants were recruited from the local area. Study procedures included anthropometrics and vitals, handgrip testing, and echocardiography performed at rest and during isometric handgrip exercise. Data were reported as mean±SD. The study enrolled 107 preterm and 48 term participants. Preterm participants (gestational age: 29.5±2.5 weeks) were shorter with higher body mass index (P<0.001) compared with term participants. Preterm participants exhibited smaller LV end-diastolic volume index (50.8±10.1 versus 56.9±10.0 mL/m2, P<0.001), LV stroke volume index (29.6±6.0 versus 34.1±6.5 mL/m2, P<0.001), and LV mass index (67.2±13.1 versus 73.3±14.2 g/m2, P=0.002) compared with term individuals. Preterm participants also had subclinical reductions in LV peak systolic tissue velocity and peak early diastolic tissue velocity lateral at rest. Isometric handgrip exercise promoted a reduction in diastolic function and an increase in hemodynamic measures, but changes during isometric handgrip exercise were similar between groups. Adolescents and adults born preterm exhibit overall normal cardiac function despite smaller cardiac volumes and mass compared with individuals born full term. Effects are most pronounced at the lowest gestational ages.

The impact of pH value on the transfer and release dynamics of doxorubicin facilitated by carbon nanotubes within the capillary network surrounding cancerous tumors through molecular dynamics simulation

Among the pharmacological agents employed in cancer therapy, doxorubicin holds a prominent place due to its widespread use and potent cytotoxic effects and doxorubicin offers considerable promise in combating cancer, its administration requires careful consideration of the delicate balance between therapeutic benefit and potential harm, highlighting the intricate landscape of cancer treatment. Molecular dynamics simulation was used in this research to evaluate the effect of pH on the transfer and release kinetics of doxorubicin via carbon nanotubes within the capillary network surrounding cancer tumors. Upon examination of the acquired data, it became evident that following a duration of 10 ns, the temperature of the scrutinized structure stabilized at 310 K. Additionally, the analysis revealed that over the same period, the potential energy of examined structure reached a convergence point of 5.68 kcal/mol. Moreover, as the pH level increased from 3 to 11, a notable reduction in the maximum velocity of particle motion was detected, diminishing from 0.0028 to 0.0021 Å/fs. This elevation in pH led to a decline in the interaction between the vessel and solute, decreasing from 0.57 to 0.42 kcal/mol. Similarly, the interaction between the vessel and tumor experienced a decline, escalating from 6.95 to 6.05 kcal/mol with the pH increased from 3 to 11. Lastly, the pH elevation resulted in a marked reduction in the rate of drug release, decreasing from 84 to 46 %. This work concluded that MD simulations greatly enhanced the progress of pH-responsive CNT-based drug delivery systems. By offering comprehensive understanding of their behavior in acidic tumor environments, these simulations optimized these systems for targeted cancer treatment.

The transient thermomechanical behavior of solid oxide fuel cell during the operation condition variations

Solid oxide fuel cell (SOFC) is a promising energy conversion technology with high efficiency, low emission and fuel flexibility. In practical and dynamic operation, the thermal stress at the interface of different layers can cause cracks or even thermal mechanical failure. This study investigates the transient thermomechanical behavior of SOFC under changing operating conditions. A three-dimensional dynamical model is developed by considering the electrochemical reaction, electron and ion transport, gas diffusion, heat and momentum transfer, and thermal-mechanical interaction. When the operating conditions vary, the time it takes for the thermal stress to reach a steady state is consistent with the time required for heat transfer to stabilize. The electrolyte layer is subjected to the maximum gradient of thermal stress change after the voltage is switched. With an increase in the inlet gas temperature, the change in the cell temperature can be divided into two stages: a rapid rise and a slow rise. Appropriate prolongation of the temperature rise time is beneficial to the thermal stability of SOFC. The increase in inlet gas temperature changes the distribution trend of cell temperature and thermal stress, while the 50 % reduction in cathode and anode inlet velocity changes its magnitude.

A comparative study of using geophysical methods for imaging subsurface voids of various sizes and at different depths

Subsurface voids pose significant geohazards, underscoring the need for their timely detection in order to mitigate the associated hazard. We report on a field study aimed at the comparative assessment of electrical resistivity tomography (ERT), seismic refraction tomography (SRT), and the multichannel analysis of surface waves (MASW) for void mapping in karstic regions. The field surveys were conducted at a site in central Texas, of typical karstic geomorphology, and involved the co-located deployment of ERT, SRT and MASW arrays. Post-surveying, boreholes were drilled at select locations for verification purposes. It is shown that MASW demonstrated limited ability to resolve voids due to its inherent theoretical limitations. In contrast, ERT revealed high-resistivity air-filled zones, and low-resistivity soil-filled regions, which aligned well with post-survey borehole logs, although deeper voids remained largely undetected. SRT clearly delineated voids through velocity reductions, but smoothing effects overestimated void velocities. Using ERT and SRT jointly provided improved void characterization compared to single-method-based interpretations, with ERT determining void type and SRT delineating boundaries. Despite the relative success of the joint ERT-SRT application, it is evident that without the corroboration provided by invasive testing, definitive void localization and characterization under arbitrary site conditions remains elusive.

Electronic structure and phonon transport properties of HfSe2 under in-plane strain and finite temperature

The electronic structure and phonon transport properties of HfSe2 under different in-plane strains at finite temperatures are systematically investigated by combining first-principles calculations with machine learning force field molecular dynamics simulations. Within a strain range of -3% to 3%, the electronic band gap value of HfSe2 varies between 0.39 and 0.87 eV. Under compressive strain, the conduction band minimum moves towards the Fermi level, with the distribution of electrons near the valence band maximum becoming more delocalized. This will reduce the scattering of electrons during the transport process, helping to improve the carrier mobility. Under tensile strain, the localization of the density of states near the valence band maximum is strengthened, accompanied by enhanced metallic properties of the Hf-Se bonds, which facilitates the enhancement of the thermoelectric power factor. Both compressive and tensile strains intensify the coupling of phonon normal modes with phonon scattering, and elevating the temperature amplifies this impact. The anharmonicity-induced reduction in phonon frequencies is especially pronounced for modes in the vicinity of the Debye frequency. This not only curtails the phonon lifetimes but also diminishes the lattice thermal conductivity through the enhancement of vibrational coupling among optical branches and the reduction of the group velocity in acoustic branches. These results demonstrate the synergistic effects of strain and temperature on the electronic structure and phonon transport of HfSe2.

Robust optimization of geometrical properties of flow diverter stents for treating cerebral aneurysm: A proof-of-concept study

This study presents a novel approach to optimize the design of flow diverter (FD) stents for cerebral aneurysm (CA) treatment. By addressing sources of uncertainty in cardiovascular simulations, including geometrical and physical properties and boundary conditions, we aim to assess the applicability of robust optimization techniques to the FD design, establishing a foundation for acquiring robust FDs that are capable of operating consistently under various real-world scenarios. Blood flow in a simplified 2-dimensional CA and FD model was simulated through computational fluid dynamics (CFD). A design space exploration method, incorporating Latin hypercube sampling and Kriging surrogate models, was employed to obtain the optimal solution. The objective was to maximize the reduction in velocity and vorticity within the CA sac. This study used non-intrusive polynomial chaos expansion (PCE) to quantify and propagate the input uncertainties through the computational model and compute the statistical moments of velocity and vorticity reductions. To assess the effect of uncertain sources on objective functions, a sensitivity analysis method based on Sobol indices was applied. Robust optimization involved simultaneously optimizing the mean and standard deviation of velocity reduction. Additionally, we accounted for patients’ specific conditions and repeated the robust optimization. The results indicate that blood Hematocrit and inlet velocity are the most impactful uncertain sources in FD optimization. Moreover, the obtained Pareto front shows that in robust designs, FD struts are concentrated in the distal region of the CA neck, while optimal designs have more struts in the proximal region. This study proposes an FD that compromises robustness and optimality with a velocity reduction of 72.31 % and a standard deviation of 0.00343.

Chebyshev spectral Newton iterative analysis on unsteady oblique stagnation flow of Maxwell fluids over an oscillating-rotating disk with Cattaneo–Christov double diffusion

Oblique stagnation flow on a rotating disk is commonly observed in processes such as spinning coating and thin film deposition techniques. The investigation of the unsteady oblique stagnation point flow for Maxwell fluid over an oscillating-rotating disk embedded in a porous medium is meticulously conducted by employing the Darcy–Maxwell framework in conjunction with Cattaneo–Christov double diffusion model. A transformation of similarity is applied to reframe the governing equations into a system of non-dimensional coupled partial differential equations, whose numerical solutions are secured by the Chebyshev Spectral Newton Iterative Scheme. The outcomes underscore that an escalation in the Darcy parameter escalates the resistance within the porous medium, consequently leading to a reduction in velocity. Both the first-order slip and the second-order slip mitigate the fluid's interaction with the disk wall, leading to a retardation in flow velocity. Additionally, the presence of augmented thermal radiation parameters is observed to enhance heat transfer efficiency, resulting in a more homogenized temperature distribution. The two-dimensional and three-dimensional streamlines provide a precise depiction of the flow characteristics at the oblique stagnation point on the oscillating-rotating disk. These findings offer a theoretical foundation that can be instrumental for forthcoming research in analogous fields.

Exploring coupling effects of rainfall and surface roughness on the sheet flow velocity

Accurately describing the path of sheet flow (SF) is crucial in soil erosion. Raindrop impact and underlying surface conditions can affect the SF velocity by changing the velocity profile. However, since this information is rarely known, the estimation of SF velocity is inaccurate. A series of upstream inflow and rainfall experiments were carried out on an impermeable flume to determine the coupling effects of rainfall and rough bed surfaces on the SF velocity and correction factor (α). The results showed that the roughness of the bed surface had a more pronounced effect on reducing the mean velocity compared to the surface velocity in both cases with and without raindrop impact. The raindrop impact notably reduced the flow velocity near the water surface, while the mean velocity slightly decreased or remained almost constant with increasing rainfall intensity. The reduction in SF velocity can be explained by the combined effects of the roughness reducing the mean velocity (up to 33.52%) and the raindrop impact reducing the surface velocity (up to 25.43%). In addition, α was not a constant when the SF was subjected to raindrop impact. The rainfall was found to increase α, while the roughness of the bed surface reduced α for all cases. Finally, a model was created to forecast α based on the ratio of water depth to roughness height, hydraulic slope, and rain Reynolds number. The results are valuable in soil erosion by providing accurate α for estimating the surface and mean velocities of SF.

Experimental jet control with Bayesian optimization and persistent data topology

This study experimentally optimizes the mixing of a turbulent jet at Reynolds number 10 000 with the surrounding air by targeted shear layer actuation. The forcing is composed of superposed harmonic signals of different azimuthal wavenumber m generated by eight loudspeakers circumferentially distributed around the nozzle lip. Amplitudes and frequencies of the individual harmonic contributions serve as optimization parameters, and the time-averaged centerline velocity downstream of the potential core is used as a metric for mixing optimization. The actuation is optimized through Bayesian optimization. Three search spaces are explored—axisymmetric forcing, m = 0, superposed axisymmetric and helical forcing, m∈{0,1}, and axisymmetric actuation combined with two counter-rotating helical modes, m∈{−1,0,1}. High-speed particle image velocimetry (PIV) is employed to analyze the jet response to the optimized forcing. The optimization processes are analyzed by persistent data topology. In the search space of axisymmetric excitation, the routine identifies an actuation at the natural frequency of the flow to be most efficient, with the centerline velocity being decreased by 15%. The optimal solutions in both the two-mode and three-mode search space converge to a similar forcing with one axial and one helical mode combined at a frequency ratio of around 2.3. Spectral analysis of the PIV images reveals that for the identified optimal forcing frequencies, a non-linear interaction between forced and natural structures in the jet flow is triggered, leading to a reduction in centerline velocity of around 35%. The topology of the most complex search space from the discrete data reveals four basins of attractions, classified into three forcing patterns including axisymmetric, axisymmetric-helical, and axisymmetric-flapping. Two deep basins are related to the optimal pattern found as axisymmetric-helical, and the others are shallower.

Sodium-dependent glucose transporter 2 inhibitors effects on myocardial function in patients with type 2 diabetes and asymptomatic heart failure.

Sodium-dependent glucose transporter 2 inhibitors (SGLT2i) have shown efficacy in reducing heart failure (HF) burden in a very heterogeneous groups of patients, raising doubts about some contemporary assumptions of their mechanism of action. We previously published a prospective observational study that evaluated mechanisms of action of SGLT2i in patients with type 2 diabetes who were in HF stages A and B on dual hypoglycemic therapy. Two groups of patients were included in the study: the ones receiving SGLT2i as an add-on agent to metformin and the others on dipeptidyl peptidase-4 inhibitors as an add-on to metformin due to suboptimal glycemic control. To evaluate the outcomes regarding natriuretic peptide, oxidative stress, inflammation, blood pressure, heart rate, cardiac function, and body weight. The study outcomes were examined by dividing each treatment arm into two subgroups according to baseline parameters of global longitudinal strain (GLS), N-terminal pro-brain natriuretic peptide, myeloperoxidase (MPO), high-sensitivity C-reactive protein (hsCRP), and systolic and diastolic blood pressure. To evaluate the possible predictors of observed changes in the SGLT2i arm during follow-up, a rise in stroke volume index, body mass index (BMI) decrease, and lack of heart rate increase, linear regression analysis was performed. There was a greater reduction of MPO, hsCRP, GLS, and blood pressure in the groups with higher baseline values of mentioned parameters irrespective of the therapeutic arm after 6 months of follow-up. Significant independent predictors of heart rate decrease were a reduction in early mitral inflow velocity to early diastolic mitral annular velocity at the interventricular septal annulus ratio and BMI, while the predictor of stroke volume index increase was SGLT2i therapy itself. SGLT2i affect body composition, reduce cardiac load, improve diastolic/systolic function, and attenuate the sympathetic response. Glycemic control contributes to the improvement of heart function, blood pressure control, oxidative stress, and reduction in inflammation.

The influence of large wood on sediment routing and flow characteristics: A study in a low-order stream in the southern brazilian plateau

The coupling of sediment sources varies in terms of efficiency and availability based on the frequency and intensity patterns of rainfall events over time. It is commonly assumed that reaches with steeper gradients have higher longitudinal connectivity, while lower gradient reaches have lower longitudinal connectivity. However, considering that the longitudinal connectivity of channels is not always perfectly established, this conception regarding channel gradient may not always hold true. In forested regions, elements such as large wood can be the main agents of this disconnectivity. Thus, this study investigates the effects of large wood on sediment flux, flow characteristics and channel morphology in the context of the Atlantic Forest Biome in a low-order stream in the southern Brazilian plateau. To achieve this, measurements of hydrological variables, characterization of sediments, and channel morphology were conducted. Hydraulic and morphological variables were estimated to define hydraulic signatures for each river section. The influences of large wood barriers in the study section were highlighted through an analysis of hydraulic characteristics at different cross-sections and the assessment of morphological variables. The investigation revealed a tendency for a reduction in velocity of approximately 90 % in low-discharge conditions in sections where large wood barriers were present. In the case of high-magnitude events, the velocity reduction was considerably lower. Additionally, it was found that each large wood deposit presented uniqueness, and the structural characteristics of each reflected the potential for system disconnectivity. Finally, it was observed that both barriers have the capacity to store sediments, leading to the constriction of the cross-section due to the formation of sediment bars, although surveys revealed that fine sediments were poorly retained in both barriers.

Novel treatments for the radiative-magnetive Ellis hybrid nanofluids flow inside stenotic shrinking artery with imposed convective slip boundary conditions and entropy generation: An application in cardiovascular disease

This research delves into the theoretical and computational analysis of blood flow dynamics within a constricted, porous artery using a novel hybrid nanofluid model known as the Ellis model, which incorporates gold and silver nanoparticles. The investigation encompasses a spectrum of physical phenomena, including magnetic effects, Darcy-Forchheimer porous medium flow, viscous dissipation, and non-linear thermal radiation. Additionally, a convective slip boundary condition is applied at the arterial surface. By transforming the governing nonlinear partial differential equations into nonlinear ordinary differential equations, the study facilitates a comprehensive analysis. Subsequently, employing the bvp4c algorithm in MATLAB enables the numerical solution of these equations, yielding dual solutions for the system. Graphical representations are then utilized to elucidate various profiles, including velocity, temperature, skin friction coefficient, Nusselt number, and entropy. The findings highlight intriguing trends, such as the contrasting behaviors of skin friction and Nusselt number between the Au/Blood nanofluid and the Au − Ag/Blood hybrid nanofluid. Dual solutions can not be found beyond the critical values of suction (Sc) and curvature (γc) parameters. The critical values Sc are 2.3554 and 2.3170; γc are 0.2248 and 0.2654 for Au/Blood and Au − Ag/Blood, respectively. Moreover, insights are gained into the influence of magnetic field, Darcy-Forchheimer parameters on velocity reduction and the effect of the Ellis fluid, velocity slip parameters on temperature reduction profile. The heat transference rate increases in the situation of augmentation in shrinking parameyer and thermal radiation effect, which helps remove the toxic plaque from the blood flowing at the surface of the artery. Notably, the study underscores the significance of nanoparticle presence, porous and magnetic field parameters in enhancing entropy near the artery, with implications for cancer treatment and stroke prevention strategies.

Experimental investigation of mechanical and durability performances of self-compacting concrete blended with bagasse ash, metakaolin, and glass fiber

This study investigated the effects of using bagasse ash (BA) and metakaolin (MK) together as substitutes for cement in self-compacting concrete (SCC), together with the addition of glass fiber (GF), on the physical and mechanical characteristics of concrete. Eighteen SCC mixes were created, each containing different proportions of BA (0%, 10%, 15%, and 20%), MK (0%, 10%, 15%, and 20%), and BA and MK collectively (10% + 5% and 10% + 10%) as cement replacements with and without 0.1% GF. Using the results of the slump flow, T500 slump flow, V-funnel, and L-box tests, the performance of fresh SCC was determined. Furthermore, this study evaluated the strength, durability, and microstructural properties of the SCC samples. The SCC mix blended with 10% BA and 5% MK revealed better flowability as the slump flow increased from 692 mm to 715 mm. A strong linear correlation was discovered between the slump flow values (mm) and V-funnel duration (sec) and blocking ratio (H2/H1) with R2 = 0.8876 and R2 = 0.8467, respectively. Of all test mixes, the SCC mix blended with 10% BA, 5% MK, and 0.1% GF (SCC1B10M5) demonstrated the highest degree of strength. At 56 days, the 10% BA, 5% MK, and 0.1 GF mix had 12.8%, 25.7%, and 22.2% higher compressive, flexural, and splitting tensile strengths than the control mix, respectively. SCC, combined with BA, MK, and GF, outperformed the control mix. After immersion in a 3% H2SO4 solution, the SCC mix having 10% BA, 5% MK, and 0.1% GF experienced a minimum reduction in weight loss and ultrasonic pulse velocity of 1.01% and 3.1%, respectively. Additionally, there was a decrease of 29.4% in the percentage of charges passed. The ideal composition was achieved by incorporating 10% BA, 5% MK, and 0.1% GF into the SCC mixture, resulting in a dense structure without any visible pores or cracks during the microstructural analysis.

Optimization design of hydrocyclone with overflow slit structure based on experimental investigation and numerical simulation analysis

This study aims to address the issue of high energy consumption in the hydrocyclone separation process. By introducing a novel slotted overflow pipe structure and utilizing experimental and response surface optimization methods, the optimal parameters were determined. The research results indicate that the number of slots, slot angles, and positioning dimensions significantly influence the performance of the hydrocyclone separator. The optimal combination was found to be three layers of slots, a positioning dimension of 5.3 mm, and a slot angle of 58°. In a Φ100mm hydrocyclone separator, validated through multiple experiments, the separation efficiency increased by 0.26% and the pressure drop reduced by 24.88% under a flow rate of 900 ml/s. CFD simulation verified the reduction in internal flow field velocity and pressure drop due to the slotted structure. Therefore, this study provides an effective reference for designing efficient and low-energy hydrocyclone separators.

An Experimental Investigation on the Effects of Temperature and Confining Pressure on the Static and Dynamic Behaviors of Shale Rocks

Abstract To better understand the associated thermal and mechanical effects on the elastic behaviors of shale rocks, we examine the shale rocks at reservoir stress (static) and elastic conditions (dynamic) at varying temperature (25–110°C) and pressure (5–55 MPa) conditions through coupling dynamic–static experimental measurements. The results illustrate that the shale’s P- and S-wave velocities increase with the increasing confining pressure but decrease with the elevated temperature. For the pressure history, ultrasonic P-wave velocities upon hydrostatic unloading are slightly larger than the loading ones, whereas S-wave velocities are almost overlapping together. Meanwhile, the temperature elevation causes much less velocity reduction at a higher confining pressure than lower confining pressure. The measured data demonstrate that the static bulk modulus is more sensitive to the confining pressure than the dynamic bulk modulus. Moreover, with the elevated temperature, the dynamic bulk moduli separate by showing a decreasing trend in either hydrostatic loading or unloading. The loading–unloading cycle shows that the static bulk moduli present values approaching the dynamic ones at all temperature levels when the confining pressure is initially unloaded from the maximum pressure. Both static and dynamic bulk moduli decrease with the continued unloading, with more decrement for the static bulk modulus. The coupling effects of the pressure and temperature on the static and elastic properties of shale samples imply that, in the practical shale reservoir characterization process, temperature and pressure influences should be considered to characterize the relation of dynamic and static properties of shale rocks. The laboratory investigations on shales imply that the relation of dynamic and static properties is pressure dependent mainly due to the intrinsic behavior of fracture, soft pore, and microstructure in the rock frame.

Evaluating Vegetation Effects on Wave Attenuation and Dune Erosion during Hurricane

This study employs the XBeach surfbeat model (XBSB) to explore the effects of vegetation on wave attenuation and dune erosion in a case study of Mexico Beach during Hurricane Michael. The XBSB model was validated against laboratory experiments of wave-induced dune erosion and wave attenuation by vegetation. In the case study of vegetation on dunes in Mexico Beach during Hurricane Michael, different vegetation drag coefficients were evaluated to investigate the effects of vegetation on wave attenuation and dune erosion. LiDAR data of dune profiles before and after Hurricane Michael were used for model validation. The findings reveal that vegetation on dunes significantly affects wave attenuation and dune erosion. Under vegetated conditions, as the vegetation drag coefficient value increases, wave attenuation also increases, leading to a reduction of dune erosion. An increase in vegetation density enhances wave attenuation in the vegetated area, including reductions in significant wave height and flow velocity. However, the rate of change in attenuation decreases as the vegetation density increases. Through simulations under regular wave condition on Mexico Beach, an optimal vegetation density was identified as 800 units/m2. Beyond this density, additional vegetation does not substantially improve wave attenuation. Furthermore, the position of the dune crest elevation is related to the location where the alongshore flow velocity begins to decrease. The findings highlight the essential role of coastal vegetation in enhancing coastal resilience against hurricanes.