Rotational Shear Research Articles

Dependence of Stellar Differential Rotation on Effective Temperature and Rotation: An Analysis from Starspot Transit Mapping

Stellar rotation is crucial for studying stellar evolution, since it provides information about age, angular momentum transfer, and magnetic fields of stars. In the case of the Sun, due to its proximity, detailed observation of sunspots at various latitudes and longitudes allows a precise estimation of the solar rotation period and its differential rotation. Here, we present for the first time an analysis of stellar differential rotation using starspot transit mapping as a means of detecting differential shear in solar-type and M stars. The aim of this study is to investigate the relationship between rotational shear, ΔΩ, and both the star's effective temperature (T eff) and its average rotation period (). We present differential rotation profiles derived from previously collected spot transit mapping data for 13 slowly rotating stars (P rot ≥ 4.5 days), with spectral types ranging from M to F, which were observed by the Kepler and CoRoT satellites. Our findings reveal a significant negative correlation between rotational shear and the mean period of stellar rotation (correlation coefficient of −0.77), which may be an indicator of stellar age. On the other hand, a weak correlation was observed between differential rotation and the effective temperature of the stars. Overall, the study provides valuable insights into the complex relationship between stellar parameters and differential rotation, which may enhance our understanding of stellar evolution and magnetic dynamos.

Frictional mid‐spliced shear links for eccentrically braced frames

AbstractAccording to the AISC Seismic Provisions for Structural Steel Buildings (AISC341‐16) and EC8, the inelastic rotation demand at the design story drift is limited to 0.08 rad for I‐shape shear links in eccentrically braced frames (EBFs). Numerical studies on EBF archetypes show that the single‐sided inelastic rotation demands can be much higher than the limiting value. In addition, these links can fail due to low‐cycle fatigue (LCF) which depends on the loading history. A mid‐spliced end‐plated detachable replaceable link has recently been developed to promote easy replacement of end‐plated links. In this paper, a frictional mid‐spliced shear link is developed to increase the inelastic link rotation capacity and LCF life of shear links. The proposed link utilizes a splice connection at the mid‐length, where frictional faying surfaces are introduced to dissipate energy. Slip at the mid‐splice connection causes a relative vertical displacement between the link ends which eventually reduces the rotation demands on the I‐shape members. Experimental and numerical studies were conducted to study the proposed link concept. Three conventional and eight frictional mid‐spliced links were tested using a nearly full‐scale test setup. The results showed that the proposed links have a pinched link shear versus link rotation response. The links were able to sustain a link rotation demand of 0.23 rad together with a significant increase in their LCF life. Numerical studies were conducted to investigate the link rotation, interstory drift, and residual interstory drift of EBF archetypes equipped with the proposed frictional link.

Investigating charge transportation and photo-responsive outcome of a Schottky diode fabricated by 2-amino terephthalic acid directed supramolecular Mn(II)-metallogel

This study investigates a supramolecular metallogel formed using an ultrasonication technique and employing manganese acetate tetrahydrate as a metal salt, 2-amino terephthalic acid (ATA) as an organic gelator, and N,N′-dimethyl formamide and dimethyl sulfoxide as mixed solvents. The mechanical toughness and viscoelastic parameters of the metallogel material were well demonstrated by rheology-based experimental values of storage and loss moduli with rotational frequency, shear strain, and shear stress of the Mn(II)-metallogel (Mn-ATA). The microstructural analysis along with chemical composition were shown using field emission scanning electron microscopy and energy dispersive X-ray analysis-based elemental research. Analysis of the infrared spectrum aided in determining how Mn-ATA was formed. Electrospray ionization mass investigation of Mn-ATA demonstrated the existence of several metallogel components and their engagement in producing the metallogel structure. Different diode parameters (i.e. photosensitivity, photoconductivity sensitivity, responsivity, specific detectivity, ideality factor, barrier height, and series resistance were measured, revealing the semiconducting property of the metallogel. The current–voltage characteristics of a Mn-ATA-based thin-film type metal–semiconductor junction device demonstrated non-linear rectifying behavior, indicating Schottky diode behavior with dominating electronic-charge transport features. The device displayed an improved rectifying property under illumination, which also implied higher conductivity. The device's measured conductivity in the low-voltage domain (equivalent to ohmic behavior) was 1.03 × 10−5 and 4.12 × 10−5 Sm−1 under darkness and illumination, respectively, implying photo-responsive behavior.

Design of a ternary synergistic network of HDPE/BN/CNT composites with an aligned shish-kebab structure for enhanced thermal conductivity and tensile strength

Fabricating polymer composites with excellent thermomechanical properties remains a challenge due to the tradeoff between high filler loading and loss of strength. Conventional composites made of randomly oriented lamellae and aggregated fillers fail to construct thermally conductive pathways for filler-filler or filler-crystal contacts. To address this issue, a synergistically ternary network composed of aligned BN and elongated CNT in a shish-kebab structure has been prepared by an in-house Rotation Shear System (RSS). The composite with 20 wt% BN and 5 wt% CNT achieved a high thermal conductivity of 2.37 W/(mK) under shear modification. The tensile strength and Vicat softening temperature of the composite are 2.29 times higher and 21.9 °C greater than those of unsheared samples. Such superior thermal and mechanical properties are mainly attributed to the interlocking shish-kebab structure, which serves as a support skeleton in composites, where aligned BN and CNT construct a heat-resistant barrier. This work provides an effective strategy to fabricate high thermally conductive composites with excellent mechanical properties, providing new insights into reducing material replacement frequency under extreme operating conditions.

An injectable MB/BG@LG sustained release lipid gel with antibacterial and osteogenic properties for efficient treatment of chronic periodontitis in rats

Periodontitis is a chronic inflammatory disease characterized by the colonization of pathogenic microorganisms and the loss of periodontal supporting tissue. However, the existing local drug delivery system for periodontitis has some problems including subpar antibacterial impact, easy loss, and unsatisfactory periodontal regeneration. In this study, a multi-functional and sustained release drug delivery system (MB/[email protected]) was developed by encapsulating methylene blue (MB) and bioactive glass (BG) into the lipid gel (LG) precursor by Macrosol technology. The properties of MB/[email protected] were characterized using a scanning electron microscope, a dynamic shear rotation rheometer, and a release curve. The results showed that MB/[email protected] could not only sustained release for 16 days, but also quickly fill the irregular bone defect caused by periodontitis through in situ hydration. Under 660 ​nm light irradiation, methylene blue-produced reactive oxygen species (ROS) can reduce local inflammatory response by inhibiting bacterial growth. In addition, in vitro and vivo experiments have shown that MB/[email protected] can effectively promote periodontal tissue regeneration by reducing inflammatory response, promoting cell proliferation and osteogenic differentiation. In summary, MB/[email protected] exhibited excellent adhesion properties, self-assembly properties, and superior drug release control capabilities, which improved the clinical feasibility of its application in complex oral environments.

Rotational radial shear in the low solar photosphere

Context. Radial differential rotation is an important physical ingredient in stellar dynamo theory. In the case of the Sun, heliosismology techniques have revealed the existence of a near-surface shear layer covering 15–20% of the upper convection zone. It was recently shown that the rotation velocity gradient is not uniform in this layer and that it displays a steep increase in a shallow layer near the surface. Aims. We report the detection of a rotation velocity depth-gradient in the low photosphere that is not accessible to heliosismology techniques. Methods. We applied differential interferometric methods to spectroscopic data obtained with the solar telescope THEMIS, which is equipped with an efficient adaptative optics system. The detection was based on the measurement of a systematic east-west shift between images of the solar granulation at different depths in the FeI 630.15 nm at the center of the solar disk. The same technique was applied to obtain the depth-difference between the images from their perspective shift when they are observed away from the disk center. Both THEMIS and HINODE/SOT data were used for the height-difference measurement, giving similar results. Results. At the center of the solar disk, we measured a systematic retrograde shift of the photospheric granular structures on the east-west axis and with no shift in the north-south direction. The retrograde shift increases linearly with height. We interpret these findings as a signature of a steep decrease in the angular velocity in the low photosphere. Conclusions. The rotational radial shear in the low solar photosphere is likely related to the dynamics of the subsurface shear layer. Its measurement yields a valuable constraint on the numerical simulations of the solar upper convection zone.

Rheology of eco-friendly mortars - Effect of industrial wastes additions

– Mortar is a mixture of sand, cement, water and eventually additives. With the environmentalissues, mortars are increasingly formulated with mineral additions as a substitute for cement in order toproduce ecological mortars. It is one of the most widely used cementitious materials in the field ofconstruction and civil engineering after concrete. Mortar placement techniques are evolving day by day,such as pumping, spraying and injection. Therefore, knowing the rheological behavior of mortars becomesmore and more crucial to master their implementation techniques. This study presents the development ofa vane rheometer to estimate the plastic viscosity yield stress of mortars. The rheological parameters weredeveloped from measurements using a procedure to convert data from moment torque and rotational speedto shear stresses versus shear rate. The procedure used considered the locally sheared material as a Binghamfluid and calculated the characteristic shear rate from the quilt analogy. The device was tested with threeexperimental programs in which many rheological parameters of the compositions of different mortars werecalculated. The results obtained validated the developed rheometer test procedure and confirmed that thetest results are reproducible and repeatable. Measurements were made on different compositions of mortarof each mineral addition, altering the amount of blast furnace slag (BFS) and fly ash (FA) in order toevaluate the impact of supplemental cementitious materials and industrial wastes on the rheologicalcharacteristics (plastic viscosity and yield stress) of eco-friendly mortar..

Lumbar vertebropexy after unilateral total facetectomy

Background ContextPosterior decompression with spinal instrumentation and fusion is associated with well-known complications. Alternatives that include decompression and restoration of native stability of the motion segment without fusion continue to be explored, however, an ideal solution has yet to be identified. PurposeThe aim of this study was to test two different synthetic lumbar vertebral stabilization techniques that can be used after unilateral total facetectomy. Study designBiomechanical cadaveric study. MethodsTwelve spinal segments were biomechanically tested after unilateral total facetectomy and stabilized with a FiberTape cerclage. The cerclage was pulled through the superior and inferior spinous process (interspinous technique) or through the spinous process and around both laminae (spinolaminar technique). The specimens were tested after (1) unilateral total facetectomy, (2) interspinous vertebropexy and (3) spinolaminar vertebropexy. The segments were loaded in flexion-extension (FE), lateral shear (LS), lateral bending (LB), anterior shear (AS) and axial rotation (AR). ResultsUnilateral facetectomy increased native ROM in FE by 10.6% (7.6%–12.6%), in LS by 25.8% (18.7%–28.4%), in LB 7.5% (4.6%–12.7%), in AS 39.4% (22.6%–49.2%), and in AR by 27.2% (15.8%–38.6%). Interspinous vertebropexy significantly reduced ROM after unilateral facetectomy: in FE by 73% (p=.001), in LS by 23% (p=.001), in LB by 13% (p=.003), in AS by 16% (p=.007), and in AR by 20% (p=.001). In FE and LS the ROM was lower than in the baseline/native condition. In AS and AR, the baseline ROM was not reached by 17% and 1%, respectively. Spinolaminar vertebropexy significantly reduced ROM after unilateral facetectomy: in FE by 74% (p=.001), in LS by 24% (p=.001), in LB by 13% (p=.003), in AS by 28% (p=.004), and in AR by 15 % (p=.001). Baseline ROM was not reached by 9% in AR. ConclusionInterspinous vertebropexy seems to sufficiently counteract destabilization after unilateral total facetectomy, and limits range of motion in flexion and extension while avoiding full segmental immobilization. Spinolaminar vertebropexy additionally restores native anteroposterior stability, allowing satisfactory control of shear forces after facetectomy. Clinical significanceLumbar vertebropexy seems promising to counteract the destabilizating effect of facetectomy by targeted stabilization.

Combined influence of rotary inertia and shear coefficient on flexural frequencies of Timoshenko beam: numerical experiments

Combined influence of rotary inertia and shear coefficient on flexural frequencies of Timoshenko beam: numerical experiments

Comprehensive Euler/Lagrange modelling including particle erosion for confined gas-solid flows

The present research aims to assess the capability of a comprehensive Euler/Lagrange approach for predicting gas-solid flows and the associated solid particle erosion. The open-source code OpenFOAM® 4.1 was used to carry out the numerical simulations, where the standard Lagrangian libraries were substantially extended to account for all necessary models. Particles are tracked considering both translational and rotational motion as well as all relevant forces, such as gravity/buoyancy, drag and transverse lift due to shear and particle rotation. The tracking time step was dynamically adapted according to the locally relevant time scales, which drastically reduces computational times. Stochastic approaches are adopted to model particle turbulent dispersion, particle collisions with rough walls and particle-particle interactions. Five solid particle erosion models, available in the literature, were considered to estimate pipe bend erosion. Three study cases are provided to validate the adopted numerical approach and erosion models extensively. The first case intends to evaluate the ability of the extended CFD code to predict the behaviour of gas-solid flows in pneumatic conveying systems. This goal is achieved by comparing the numerical results with the experimental data obtained by Huber (1997) and Huber and Sommerfeld (1994, 1998) in a pneumatic conveying system. Here, the importance of considering inter-particle collisions and surface roughness for predicting particle velocity, mass flux and mean diameter distributions in gas-solid flows is highlighted. The second and third case intend to evaluate the ability of the erosion models in estimating bend erosion in diluted gas-solid flows. The erosion data obtained experimentally by Mazumder et al. (2008) and Solnordal et al. (2015) in very dilut pneumatic conveying systems is used for validating the numerical results, neglecting now inter-particle collisions and two-way coupling. Besides a comprehensive analysis of the different influential properties on erosion, the innovation of the present study is as follows. For the first time also a temporal modification of the surface roughness due to the erosion was considered in the simulations obtained from previous measurements (Novelletto Ricardo & Sommerfeld, 2020). As the surface roughness is increased due to erosion, eventually erosion rate becomes lower. This is the result of diminishing wall collision frequency. Simulations for several degrees of surface roughness showed that larger roughness is coupled with a drastic reduction of erosion. Hence, numerical simulations neglecting wall surface roughness are not realistic. The consideration of a particle size distribution instead of mono-sized computations showed a possible reduction of erosion rate. The detailed analysis of the different single-particle erosion models revealed that the model proposed by Oka et al. (2005) and Oka and Yoshida (2005) yields the best agreement with the measurements, however particle and wall properties are needed.

Interspinous and spinolaminar synthetic vertebropexy of the lumbar spine

PurposeTo develop and test synthetic vertebral stabilization techniques (“vertebropexy”) that can be used after decompression surgery and furthermore to compare them with a standard dorsal fusion procedure.MethodsTwelve spinal segments (Th12/L1: 4, L2/3: 4, L4/5: 4) were tested in a stepwise surgical decompression and stabilization study. Stabilization was achieved with a FiberTape cerclage, which was pulled through the spinous process (interspinous technique) or through one spinous process and around both laminae (spinolaminar technique). The specimens were tested (1) in the native state, after (2) unilateral laminotomy, (3) interspinous vertebropexy and (4) spinolaminar vertebropexy. The segments were loaded in flexion–extension (FE), lateral shear (LS), lateral bending (LB), anterior shear (AS) and axial rotation (AR).ResultsInterspinous fixation significantly reduced ROM in FE by 66% (p = 0.003), in LB by 7% (p = 0.006) and in AR by 9% (p = 0.02). Shear movements (LS and AS) were also reduced, although not significantly: in LS reduction by 24% (p = 0.07), in AS reduction by 3% (p = 0.21). Spinolaminar fixation significantly reduced ROM in FE by 68% (p = 0.003), in LS by 28% (p = 0.01), in LB by 10% (p = 0.003) and AR by 8% (p = 0.003). AS was also reduced, although not significantly: reduction by 18% (p = 0.06). Overall, the techniques were largely comparable. The spinolaminar technique differed from interspinous fixation only in that it had a greater effect on shear motion.ConclusionSynthetic vertebropexy is able to reduce lumbar segmental motion, especially in flexion–extension. The spinolaminar technique affects shear forces to a greater extent than the interspinous technique.

Regularization-Based 2D Strain Tensor Imaging in Quasi-Static Ultrasound Elastography SAGE Publications.

Accurately estimating all strain components in quasi-static ultrasound elastography is crucial for the full analysis of biological media. In this study, 2D strain tensor imaging was investigated, focusing on the use of a regularization method to improve strain images. This method enforces the tissue property of (quasi-) incompressibility, while penalizing strong field variations, to smooth the displacement fields and reduce the noise in the strain components. The performance of the method was assessed with numerical simulations, phantoms, and in vivo breast tissues. For all the media examined, the results showed a significant improvement in both lateral displacement and strain, while axial fields were only slightly modified by the regularization. The introduction of penalty terms allowed us to obtain shear strain and rotation elastograms where the patterns around the inclusions/lesions were clearly visible. In phantom cases, the findings were consistent with the results obtained from the modeling of the experiments. Finally, the easier detectability of the inclusions/lesions in the final lateral strain images was associated with higher elastographic contrast-to-noise ratios (CNRs), with values in the range of [0.54-9.57] versus [0.08-0.38] before regularization.

Effects of initial fabric anisotropy on the undrained rotational shear responses of granular material using discrete element simulations

Effects of initial fabric anisotropy on the undrained rotational shear responses of granular material using discrete element simulations

GDQ computation for thermal vibration of thick FGM plates by using third-order shear deformation theory

The third-order shear deformation theory (TSDT) effects on the thick functionally graded material (FGM) plates under thermal vibration are investigated by using the generalized differential quadrature (GDQ) method. The nonlinear coefficient term of displacement field of TSDT is used to derive the equations of motion for thermal vibration of thick FGM plates. The simpler form stiffness of FGM plates under linear temperature rise is considered in the thermo-elastic stress–strain relations. The dynamic equilibrium differential equations of FGM plates in terms of partial derivatives of displacements and shear rotations subjected to partial derivatives of thermal loads, mechanical loads and inertia terms are derived. Two parametric: environment temperature and FGM power law index effects on the thermal stress and center deflection of FGM thick plates are investigated.

Regulation of Entanglement Networks under Different Shear Fields and Its Effect on the Properties of Poly(l-lactide)

Entanglement will lead to a sharp increase in viscosity and a decrease in flowability of polymers and affect their crystallization behavior adversely. Thus, it seems that disentanglement becomes a feasible way to improve the flowability and crystallization ability of polymers without adding other substances. Poly(l-lactide) (PLLA), as a renewable polymer material, has attracted increasing attention in the past decades. Accelerating crystallization of PLLA is extremely important to improve its performance. The present study utilizes a self-designed polymer melt disentanglement machine (PMDM) with PLLA as the experimental material, which can effectively promote polymer disentanglement by applying a unique complex shear field (superposition of rotational and vibrational shear fields) to a polymer melt. The experimental results show that compared with the untreated material, the disentangled ones have a lower viscosity and a higher melt flow rate and can fill the mold cavity at a lower pressure and a lower melt or mold temperature during the injection molding process. Simultaneously, the crystallization kinetics of the disentangled materials is accelerated, the crystallinity is higher under the same secondary processing conditions, and the heat resistance and mechanical properties of prepared products are better. This study provides new ideas for resolving the conflict between mechanical properties and processing flowability, improving the heat resistance of PLLA, and expanding its application range.

WASP-131 b with ESPRESSO – I. A bloated sub-Saturn on a polar orbit around a differentially rotating solar-type star

ABSTRACT In this paper, we present observations of two high-resolution transit data sets obtained with ESPRESSO of the bloated sub-Saturn planet WASP-131 b. We have simultaneous photometric observations with NGTS and EulerCam. In addition, we utilized photometric light curves from TESS, WASP, EulerCam, and TRAPPIST of multiple transits to fit for the planetary parameters and update the ephemeris. We spatially resolve the stellar surface of WASP-131 utilizing the Reloaded Rossiter McLaughlin technique to search for centre-to-limb convective variations, stellar differential rotation, and to determine the star–planet obliquity for the first time. We find WASP-131 is misaligned on a nearly retrograde orbit with a projected obliquity of $\lambda = 162.4\substack{+1.3 \\ -1.2}^{\circ }$ . In addition, we determined a stellar differential rotation shear of α = 0.61 ± 0.06 and disentangled the stellar inclination ($i_* = 40.9\substack{+13.3 \\ -8.5}^{\circ }$ ) from the projected rotational velocity, resulting in an equatorial velocity of $v_{\rm {eq}} = 7.7\substack{+1.5 \\ -1.3}$ km s−1. In turn, we determined the true 3D obliquity of $\psi = 123.7\substack{+12.8 \\ -8.0}^{\circ }$ , meaning the planet is on a perpendicular/polar orbit. Therefore, we explored possible mechanisms for the planetary system’s formation and evolution. Finally, we searched for centre-to-limb convective variations where there was a null detection, indicating that centre-to-limb convective variations are not prominent in this star or are hidden within red noise.

FULLY CHARACTERIZING SPINAL LOAD DISPLACEMENT BEHAVIOUR USING VISCOELASTIC MODELS

Lower back pain (LBP) is a global problem. Countless in vitro studies have attempted to understand LBP and inform treatment protocols such as disc replacement devices (DRDs). A common method of reporting results is applying a linear fit to load-displacement behaviour, reporting the gradient as the specimen stiffness in that axis. This is favoured for speed, simplicity and repeatability but neglects key aspects including stiffening and hysteresis. Other fits such as polynomials and double sigmoids better address these characteristics, but solution parameters lack physical representation. The aim of this study was to implement an automated method to fit spinal load-displacement behaviour using viscoelastic models.Six porcine lumbar spinal motion segments were dissected to produce isolated disc specimens. These were potted in Wood's metal, ensuring the disc midplane remained horizontal, sprayed with 0.9% saline and wrapped in saline-soaked tissue and plastic wrap to prevent dehydration. Specimens were tested using the University of Bath spine simulator operating under position control with a 400N axial preload.Specimens were approximated using representative viscoelastic elements. These models were constructed in MATLAB Simulink R2020b using the SimScape library. Solution coefficients were determined by minimizing the sum of squared errors cost function using a non-linear least squares optimization method.The models matched experimental data well with a mean % difference in model and specimen enclosed area below 6% across all axes. This indicates the ability of the model to accurately represent energy dissipated. The final models demonstrated reduced RMSEs factors of 3.6, 1.1 and 9.5 smaller than the linear fits for anterior-posterior shear, mediolateral shear and axial rotation respectively.These nonlinear viscoelastic models exhibit significantly increased qualities of fit to spinal load-displacement behaviour when compared to linear approximations. Furthermore, they have the advantage of solution parameters which are directly linked to physical elements: springs and dampers. The results from this study could be instrumental in improving the design of DRDs as a mechanism for treating LBP.

Effect of Symmetry/Asymmetry of Shear Rotation of a Plasma Column in a Radial Electric Field on the Level of Turbulent Density Fluctuations

The influence of the properties of the profile of a radial static electric field E(r) on the evolution of an unstable ion temperature–gradient (ITG) drift wave in a nonuniformly rotating plasma column in a magnetic field is studied. The effect of symmetry on the decrease in the level of turbulent fluctuations, which are associated with the limiting state of the ITG wave during its destruction, is discussed. The level of turbulence is estimated in the framework of approximation of finite amplitudes depending on the electric field structure. It is shown that the maximum decrease in the level of fluctuations occurs with a symmetrical configuration of the radial electric field.

Effects of zeolite on rheological properties of asphalt materials and asphalt-filler interaction ability

The rheological properties of asphalt materials (asphalt binder and mastic) and asphalt-filler interactions play critical roles in the performance of asphalt mixtures. However, the rheological properties of zeolite-foamed asphalt materials and zeolite-foamed asphalt-filler interactions are significantly influenced by zeolite, which is used as a foaming additive. To study the effects of zeolite on the rheological properties of asphalt materials and asphalt-filler interaction, the base asphalt, limestone filler, and two kinds of zeolites in two dehydrated states were selected to prepare zeolite asphalt/mastic and zeolite-foamed asphalt/mastic. First, the effects of zeolite on the chemical composition and micromorphology of asphalt binders were evaluated using a Fourier transform infrared spectrometer (FTIR) and fluorescence microscopy (FM), respectively. Then, the rheological properties of asphalt binders and mastics were measured by rotational viscosity (RV) and dynamic shear rheometer (DSR) tests. The results indicated that zeolite did not chemically react with the components of asphalt, and zeolite minerals played a role in volume filling and physical adsorption in asphalt, which dispersed in the asphalt in the form of floccules. Adding zeolite minerals to asphalt binders and mastics enhanced the elasticity, which was beneficial to high-temperature performance and adverse to fatigue performance. Conversely, the effect of zeolite water released by zeolite was the opposite. The effect of zeolite on the rheological properties of asphalt materials was consistent with that of zeolite minerals because the enhancing effect of zeolite minerals was dominant, offsetting the weakening effect of zeolite water in asphalt binders and mastics. The three indices, namely, intrinsic viscosity [η], Palierne-C-G* parameter, and Ziegel-B-δ parameter, were selected to evaluate the zeolite asphalt-filler interaction ability and zeolite-foamed asphalt-filler interaction ability. The results showed that the asphalt-filler interaction ability was enhanced after adding zeolite minerals to asphalt, and the influence of zeolite on asphalt-filler interaction was consistent with zeolite minerals. However, the opposite effect was observed for zeolite water.

Hemodynamic investigation of a novel rotary displacement blood pump for extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation (ECMO) is a life support system used in the treatment of severe respiratory and circulatory failure. High shear stress caused by the high rotational speed of centrifugal blood pumps can cause hemolysis and platelet activation, which are among the major factors leading to the complications of the ECMO system. In this study, a novel blood pump named rotary displacement blood pump (RDBP), which can considerably reduce rotational speed and shear stress while ensuring the normal pressure flow relationship, was proposed. We employed computational fluid dynamics (CFD) analysis to investigate the performance of RDBP under adult ECMO support operating conditions (5 L/min with 350 mmHg). The efficiency and H-Q curves of the RDBP were calculated to evaluate its hydraulic performance, and pressure, flow patterns, and shear stress distribution were analyzed to estimate the hemodynamic characteristics in the pump. In addition, the modified index of hemolysis (MIH) was calculated for the RDBP based on a Eulerian approach. The hydraulic efficiency of the RDBP was 47.28%. The velocity distribution of flow field in the pump was relatively uniform. Most of the liquid (more than 75%) in the pump was exposed to low scale shear stress (<1 Pa), which was close to normal physiological conditions. The gap area was the main distribution location of high scale shear stress. The high wall shear stress (>9 Pa) volume fraction of the RDBP was small and located in the boundary areas between the rotor's edge and the housing. The MIH value of the RDBP was 9.87 ± 0.93 (mean ± SD). The RDBP can achieve better hydraulic efficiency and hemodynamic performance at lower rotational speed. The design of this novel pump is expected to provide a new direction for developing a blood pump for ECMO.