Shear Frequency Research Articles

The Relationship Between Self-Reported Nocturnal Cough Symptoms and Acoustic Cough Monitoring

ObjectiveThis pilot investigation explored the relationship between self-reported clinical cough symptoms and objective acoustic cough data in individuals with nocturnal chronic cough. MethodsTen participants diagnosed with chronic cough with a nocturnal component underwent two study sessions, approximately 1 week apart. Participants completed questionnaires regarding cough severity and their perceptions of using a smartphone application (app) to audio record cough. Between sessions, participants utilized the continuous audio recorder while sleeping. The relationship between the number of coughs captured at night and the self-reported impact of cough awakening during sleep were analyzed. ResultsWe found strong correlations (ρ = −0.78, −0.87) between formalized Leicester Cough Questionnaire scores and acoustically determined cough frequency. However, there were large differences between the average number of self-reported cough awakening events (0-3) and the number of acoustically recorded coughs (0-639). While users expressed comfort with recording and sharing acoustic data (4.8/5 Likert rating), concerns over confidentiality in daytime use were noted (4.1/5). ConclusionFormalized cough questionnaires provide insight into chronic cough at night but may fall short in quantifying the shear frequency of coughs patients are experiencing. Although continuous audio recordings via smartphone emerged as a comfortable means for patients to supply quantifiable data regarding the impact of chronic cough during sleep, future endeavors in cough acoustic monitoring should prioritize privacy considerations for daytime use and work to share information with health care providers.

Highly Filled Waste Polyester Fiber/Low-Density Polyethylene Composites with a Better Fiber Length Retention Fabricated by a Two-Rotor Continuous Mixer

A key challenge in the utilization of waste polyester fibers (PET fibers) is the development of fiber-reinforced composites with high filler content and the improvement of fiber length retention. Herein, the effects of a two-rotor continuous mixer and a twin-screw extruder on the structure and properties of waste polyester fiber composites were evaluated. The results revealed that the mechanical properties of the composites were improved significantly with increasing fiber content, especially when processed using the twin-rotor continuous mixer. This mixer facilitated the formation of a robust fiber network structure, leading to substantial enhancements in tensile strength, flexural strength, and heat resistance. Specifically, compared to those processed by the twin-screw extruder, with 60 wt% fibers content, the tensile and flexural strengths of specimens processed by the twin-rotor continuous mixer increase by 21% and 13%, respectively. The average fiber length in specimens processed by the twin-rotor continuous mixer was 32% longer than that in specimens processed by the twin-screw extruder, attributable to the lower shear frequency and the higher tensile ratio of the former. This blending technique emerges as an effective strategy, contributing significantly to promoting the development and practical application of waste textile fiber-reinforced polymer composites.

The diagnostic value and clinical relevance of high frequency ultrasound and shear wave elastography in systemic sclerosis: an observational monocentric study

To unravel the features of skin involvement in patients with systemic sclerosis (SSc) by high frequency ultrasound (HFU) and shear wave elastography (SWE). To assess the ultrasound capabilities to distinguish SSc patients from healthy controls (HCs). We recruited a cohort of SSc patients in this cross-sectional study. HFU and SWE were used to quantify skin thickness and skin stiffness. Receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic capabilities of ultrasound in SSc. The correlation analysis was used to evaluate the clinical relevance of ultrasound measurements in SSc. 20 consecutive SSc patients and 20 age-, gender- and body mass index-matched HCs were included. The skin thickness and stiffness were significantly greater in SSc patients compared with HCs. Patients with high disease activity had higher skin thickness and stiffness compared with patients with low disease activity. The area under the ROC curve (AUC) of the dorsum of middle fingers assessed by HFU was 0.847 (95% CI, 0.761–0.933). The AUC of the forearms and dorsum of hands assessed by SWE were 0.909 (95% CI, 0.829–0.989) and 0.879 (95% CI, 0.807–0.951). Further, the combined HFU and SWE tests displayed the best diagnostic performance with an AUC of 0.980 (95% CI, 0.939–1.000). A significant positive correlation between the ultrasound measurements and the modified Rodnan skin score (mRSS) was observed. The application of ultrasound can assist with disease diagnosis, it is necessary to develop a standard operating protocol to help with future implementation of ultrasound in SSc.Key Points• The application of HFU and SWE can assist with SSc diagnosis.• The skin thickness and stiffness measured by HFU and SWE positively correlate with mRSS.• HFU and SWE enable quantitative measurement of skin thickness and stiffness of different skin sites.

Cyclic frictional response of rough rock joints under shear disturbances: Laboratory experiment and numerical simulation

The cyclic frictional response of rock joints under shear disturbances is critical for understanding the stability and durability of rock engineering structures. Laboratory experiments and numerical simulations were conducted to examine the effects of varying cyclic shear displacement amplitudes, frequencies, and cycle numbers on the macroscopic and microscopic shear characteristics of rough rock joints. The experimental results reveal significant differences in shear strength between the first few cycle and subsequent cycles during the cyclic shear process. As the number of shear cycles increases, the asperities on the contact surface gradually sustain damage, leading to a reduction in normal displacement. During cyclic shear, the peak shear load exhibits a two-stage variation with the number of cycles: an initial sharp decline followed by a gradual increase as the cycles proceed. The peak shear strength shows no obvious pattern under different shear displacement amplitudes and frequencies in the early stages of cyclic shear. As cyclic shear progresses, the peak shear strength decreases with increasing shear displacement amplitude but increases with higher shear frequency. Numerical simulations indicate that significant plastic deformation and shear wear occur on the joint surface during the initial cycles. The growth of the wear area is primarily concentrated in regions of stress concentration. Additionally, the simulations reveal that the volume of shear wear increase nonlinearly with the number of cycles. This research provides new insights into the cyclic shear behavior of rough rock joints and offers valuable references for engineering applications.

Injectable decellularized Wharton's jelly hydrogel containing CD56+ umbilical cord mesenchymal stem cell-derived exosomes for meniscus tear healing and cartilage protection

Traditional meniscectomy or suture for meniscal tear usually leads to failed self-healing, cartilage degeneration and worse osteoarthritis. The strategies that facilitate the healing process of torn meniscus and safeguard knee cartilage against degeneration will be promising for clinical therapy. The CD56+ umbilical cord mesenchymal stem cells (UCSCs) (CD56+UCSCs) were sorted from Wharton's jelly using flow cytometer. Then, the modified decellularized Wharton's Jelly hydrogel (DWJH) was combined with isolated CD56+Exos from CD56+UCSCs to fabricate DWJH/CD56+Exos. The in vitro studies were performed to characterize the DWJ (decellularized Wharton's Jelly). The injectability and rheological properties were assessed by shear rate and frequency sweep analysis. The biocompatibility and chondrogenic differentiation inducibility of DWJH/CD56+Exos were performed on human bone marrow mesenchymal stem cells (hBMSCs) and RAW 264.7 cells. The release dynamics was evaluated in vitro and in vivo experiments. As for the in vivo experiments, the operated rats that subjected to a 2 mm full-thickness longitudinal tear in right medial anterior meniscus were injected a single dose of DWJH/CD56+Exos. At 4 and 8 weeks postoperatively, torn meniscus healing and articular cartilage degeneration were evaluated by hematoxylin and eosin (H&E), safranin O/fast green (SO&FG), and Sirius red staining. In in vitro experiments, the injectable DWJH/CD56+Exos demonstrated excellent biocompatibility, exosome releasing efficiency, injectable property and chondrogenic inducibility. The results of in vivo experiments revealed that DWJH/CD56+Exos degraded over time, promoted meniscal chondrogenesis, organized meniscal extracellular matrix remodeling, safeguard articular cartilage and inhibited secondary cartilage degeneration, which accelerated further facilitated torn meniscus healing. The novel injectable DWJH/CD56+Exos promoted meniscal tear healing by promoting meniscal chondrogenesis, safeguarding articular cartilage, and inhibiting secondary cartilage degeneration.

Evaluation of sensor-enabled piezoelectric geoelectric cable in cyclic shear tests of subgrade soil under vertical cyclic loads

Of late, deformation of subgrade soil has led to an increasing number of road subsidence diseases. Real-time monitoring of subgrade deformation is critical to ensure the safety of subgrade operations. In this paper, a sensor-enabled piezoelectric geoelectric cable (SPGC) with impedance strain effect and piezoelectric effect is tested. The SPGC impedance and voltage signals obtained by cyclic shear test under vertical static load and cyclic shear test under vertical cyclic load are used to evaluate the monitoring effect. The results showed that normal stress had the greatest effect on the shear strength of the soil, whereas the normal stress and horizontal shear displacement amplitude significantly influenced the strain in the soil. Varying the normal and horizontal shear frequencies had little effect on the shear strength and strain of the soil. The normalized impedance and voltage of the SPGC, respectively, decreased and increased rapidly during the initial stage of the shear cycle; these changes were relatively small during the middle and late stages of the shear cycle. The SPGC voltage waveform revealed the changes in the shear stress and vertical displacement under different normal and horizontal shear frequencies, from which the stability of the subgrade soil under the aforementioned conditions could be evaluated. The variations in the SPGC impedance and effective voltage from the cyclic shear tests under both vertical static and vertical cyclic loads remained essentially consistent with the number of cycles. However, there was a difference in that the trough of the SPGC impedance under the vertical cyclic load was larger than that under the vertical static load; likewise, the effective SPGC voltage under the cyclic load was larger than that under the static load. Through an analysis of the SPGC impedance and voltage signals in the subgrade soil, the consistency of the SPGC-normalized impedance and effective voltage with shear stress was clarified; this helped us evaluate the health of the subgrade and monitor the characteristics of the precursor signals before a slide were to occur, thereby affording us an opportunity to issue timely warnings.

Can Hyaluronic Acid Combined with Chondroitin Sulfate in Viscosupplementation of Knee Osteoarthritis Improve Pain Symptoms and Mobility?

The objective of the present study was to assess the effect of intra-articular Hyaluronic acid (HA) and Chondroitin sulfate (CS) supplementation (Hialurom® Hondro (HH)) on pain symptoms and joint mobility. In total, 60 mg/mL sodium hyaluronate and 90 mg/mL CS were administered to 21 patients (17 females and 4 males) respecting the in-force requirements, excluding patients with some specific comorbidities. In addition to the clinical study (where the pain intensity (severity) and joint mobility were assessed), rheological characterization was conducted evaluating the following parameters: elastic modulus (G'), loss modulus (G″) oscillatory frequency (fc) at 0.5 Hz and 2.5 Hz, crossover frequency (fc), relaxation time (λ) where it was noticed that the addition of chondroitin sulfate (CS) to sodium hyaluronate (SH) significantly enhances and improves the viscoelastic properties, particularly at higher shear frequencies. A significant decrease in pain intensity felt by the subjects was found, from 7.48 (according to Wong-Baker scale)-pain close to 8 (the patient is unable to perform most activities), to more reduced values of 5.86-at 6 weeks after injection, 4.81-at 3 months after injection, and 5.24-at 6 months after injection, improvements in symptoms was fast and durable. Data related to the evolution of joint mobility show that at 6 weeks after injection, the mobility of joints increased by 17.8% and at 6 months by 35.61%. No serious adverse events were reported with undesired effects so that they would impose additional measures. Better resistance to enzymatic degradation and free radicals could be expected from the synergic combination of sodium hyaluronate and chondroitin sodium sulfate, this having a special importance for the patients, granting them the ability to perform more ample movements and reducing dependency on attendants, thus increasing quality of life.

Evolution of small-scale turbulence at large Richardson numbers

Abstract. The theory of stratified turbulent flow developed earlier by the authors is applied to data from different areas of the ocean. It is shown that turbulence can be amplified and supported even at large gradient Richardson numbers. The cause of that is the exchange between kinetic and potential energies of turbulence. Using the profiles of Brunt–Väisälä frequency and vertical current shear given in Forryan et al. (2013), the profiles of the kinetic energy dissipation rate are calculated. The results are in reasonable agreement with the experimental data.

Assessing meat quality and textural properties of broiler chickens: the impact of voltage and frequency in reversible electrical water-bath stunning

The implementation of the head-only electrical stunning procedure in poultry processing has been aimed at enhancing eating, ethical, and religious quality. However, inconsistencies in voltage and frequency standardization, along with variations in previous research outcomes, have led to numerous cases of both under-stunned and over-stunned birds. Thus, this study aimed to comprehensively evaluate the effects of varying voltages and frequencies during electrical water bath stunning on carcass quality, meat attributes, and textural properties in broiler chickens. A cohort of 240 healthy female broilers (Cobb 500, 42-days-old, 2 kg ± 0.1 kg) was meticulously selected from a commercial farm. The birds underwent exposure to different stunning voltages (2.5, 10.5, 30, and 40 V) and frequencies (50 and 300 Hz). Subsequent analyses were conducted on meat samples to assess physicochemical properties, carcass quality, and textural attributes. The findings revealed a higher incidence of petechial hemorrhage (P < 0.05) in birds stunned at 10.5 V compared to other voltage. Notably, no broken bones were recorded in birds subjected to high voltages (30 and 40 V). Low frequency (50 Hz) significantly increased the occurrence of petechial hemorrhage and simultaneously resulted in pectoralis major muscle with decreased redness (a*). Birds subjected to the 10.5 V stunning treatment exhibited a lower cooking loss percentage. Significant interactions between voltage and ageing (V × A) were observed. Birds stunned at 30 V and aged for 7 d displayed highest drip loss compared to a one-day ageing period across different voltage levels. This interaction also impacted pH values, with birds subjected to 10.5 V showing significantly lower (P < 0.05) pH at d 7 of ageing. The meat hardness was influenced by the V × A interaction, wherein birds stunned at 10.5 V exhibited lower hardness after one day of ageing compared to other voltage levels. Red wing tips, lightness (L*), adhesiveness, and resilience were also significantly impacted (P < 0.05) by the interaction between frequency and voltage. A notable 3-way interaction was observed for gumminess and chewiness (F × V × A), where the 2-way interaction between frequency and voltage (F × V) affected both parameters differently at various ageing periods. Additionally, there was a significant interaction (P < 0.05) between frequency and voltage influencing shear strength and yellowness.

Augmenting the quality and storage stability of soymilk by incorporation of untreated and ozonated oat 1,4-β-D-glucan

The study aimed to improve the quality and storage stability of novel plant-based soymilk with the incorporation of untreated (UtβG) and modified oat derived 1,4-β-D-glucan (OzβG) at varying concentrations (0, 1, and 2 % labelled as S0, S1 and S2). The treated soymilk was characterized for physical, chemical, nutritional, rheological, particle size, zeta potential, sensory and storage stability characteristics. The results revealed that 1, 4-β-D-glucan incorporation increased the acidity (0.67 to 0.73 %), viscosity (3.4 to 4.7 Cp) and ash content (0.74 to 0.92 %), however color remains natural. The frequency sweep and shear experiments showed that the 1,4-β-D-glucan modified the rheological parameters of the soymilk. The sensory analysis (n = 30) indicated that texture, mouthfeel and overall acceptability (8.38). Compared to OzβG-treated soymilk, UtβG soymilk, especially S2, exhibited superior thickening and rheological properties. The storage study indicated minimal phase separation in 1,4-β-D-glucan-incorporated samples, maintaining stability for 15 days under refrigerated conditions without compromising overall quality. Thus, this study provides valuable insights into the potential application of 1,4-β-D-glucan for improving the technological quality of soymilk that highlights possible implications for its commercialization potential.

Tunable structure and linear viscoelastic properties of poly(glycerol adipate urethane)-based elastomeric composites for tissue regeneration

Elastomeric biocomposites based on poly(glycerol adipate urethane) and hydroxyapatite were fabricated for tissue regeneration. The poly(glycerol adipate urethane) (PGAU) elastomeric composite matrices were obtained by chemical crosslinking of the poly(glycerol adipate) prepolymer (pPGA) with diisocyanate derivative of L-lysine. Two series of composites varying in the amount of L-lysine diisocyanate ethyl ester (LDI) used as a crosslinking agent were manufactured. As a ceramic filler both unmodified and L-lysine surface-modified hydroxyapatite (HAP) particles were used. The novelty of our research consists in the manufactured elastomeric materials and characterization of their linear viscoelastic (LVE) properties. The LVE properties of the composites were investigated by means of dynamic thermomechanical analysis. Frequency sweep and amplitude sweep measurements were performed in shear mode. The influence of the crosslinking agent (LDI) amount, HAP content and surface modification of HAP on the LVE properties of the composites was determined based on the analysis of the master curves of storage (G′) and loss (G″) moduli and of tanδ of the composites. Depending on the amount of LDI, HAP and surface modification, the materials differ in the values of rubber elasticity plateau modulus (G0) and G′ and G″ determined at selected shear frequencies and at the glassy state. G0 ranges from 278 kPa to 3.98 MPa, G′ in the glassy state is within the range of 219 MPa–459 MPa. The G0 values of the PGAU-based composites are within the stiffness range of soft tissue. In view of the choice of HAP as the ceramic component and the G0 values, elastomeric composites have the potential to be used as filling materials in small bone defects (due to their mechanical similarity to osteoid) as well as materials for cartilage tissue regeneration.

Effect of defatted flaxseed gum powder addition on the quality of sesame paste

The study explored the influence of defatted flaxseed gum powder (DFGP) on the stability and quality of sesame paste by measuring and analyzing its composition, color, texture, particle size, centrifugal oil separation rate, rheological properties, and microstructure. The results showed that the moisture and polysaccharide content of sesame paste was increased as the DFGP increased. Additionally, the hardness, gumminess, and chewiness of the sesame paste was improved, while the presence of particles with small particle size (1–100 ​μm) was decreased. The rate of oil precipitation was reduced by 28.99% when the amount of DFGP was 6%. The sesame paste samples exhibited pseudoplastic behavior, demonstrating shear thinning. As the shear rate increased, the apparent viscosity of sesame paste gradually decreased. Both the storage modulus (G′) and the loss modulus (G″) increased as the shear frequency increased. The microstructure observation revealed that protein and oil were evenly distributed in the sesame paste system, and the addition of DFGP enhanced the bonding between oil and protein. This study can provide valuable references for high-quality sesame paste products in the food industry.

Seismic Parametric Analysis of RC Multi-Storied Buildings with and Without Fluid Viscous Dampers

Earthquakes are enormous natural disasters that increase the energy within the structural system, causing catastrophic destruction. Various control systems, such as passive, active, hybrid, and semi active control systems, can be used to dissipate this unwanted energy. The fluid viscous damper is one such dissipation device used in this study. The goal of this project is to use a fluid viscous damper to lessen the seismic response of the Symmetrical and unsymmetrical G+9 structure in ETABS2017. To obtain the seismic response with and without a fluid viscous damper, ETABS2017 was used to analyse symmetrical and unsymmetrical structures with and without a fluid viscous damper. The analysis takes into account nonlinear temporal history, which is derived using fast nonlinear analysis of Electro data. The position and function of dampers are discussed in this study. For seismic evaluation of buildings with and without fluid viscous dampers, the equivalent static approach and response spectrum method are utilised. The structure was examined utilizing ETABs 2017 programming, with seismic zone IV and medium soil (Type II) according to IS 1893-2016. The structure’s exhibition is assessed utilizing story removal, story shear, story float, and modular periods and frequencies. The objective of this study is to about the consequences of static and reaction range examination in both longitudinal and cross over bearings for damper development with and without damper structure.

Temperature dependence of interfacial force between solid surfaces under high frequency shear

Temperature dependence of interfacial force between solid surfaces under high frequency shear

Physicochemical, Structural and Rheological Properties of Hawthorn Yam (Dioscorea rotundata) Flour

Hawthorn yam has been widely used for the development of food products. The objective of the present work was to investigate the physicochemical, structural, and rheological properties of hawthorn yam flour (CHYF). The identification of chemical composition by proximal and Fourier Transform Infrared Spectroscopy (FTIR) analysis; the morphological by Scanning Electron Microscope (SEM) and rheological properties by steady shear test, stress test, frequency sweep, temperature sweep, and pasting properties analysis were done. CHYF presents a high carbohydrate content (80.47 ± 1.14%), followed by the protein content (8.76 ± 0.58%), ash (3.56 ± 0.52%), and the lowest fat content (0.39 ± 0.06%), and different functional groups such as C=O, COO, N–H, and O-H. Flour particles present a particle size between 27 and 43µm, with spherical-oval morphology with a smooth surface. Flours present a non-Newtonian fluid shear-thinning adjusted to the Power Law model (R2 &gt; 0.99), and a characteristic of a typical strong gel material with a storage modulus (G^') higher than loss modulus (G^'') and paste temperature of 81.6 ° C with a Peak Viscosity (PV) of 750 cP. Then, it is a potential source of natural ingredients with technological properties for the food industry and the food sovereignty of many countries in the world.

Preparation and enhanced electrorheological properties of elastomers filled with rod-shaped TiO2 particles

The morphology of dispersed particles has been proven to have a significant impact on performance of electrorheological (ER) materials, while there is a lack of relevant research on its impact on the properties of electrorheological elastomers (EREs). In this study, the TiO2 particles with spherical, short rod, and long rod shape were fabricated with sol-gel method, and the EREs were prepared with these three kinds of particles as dispersion phase. Particle characterization results show that the rod-shape TiO2 particles with larger average size exhibit a combination of anatase and brookite phase. The viscoelastic properties of three types of EREs under varying strain amplitude and shear frequency were tested. The results indicate that the long rod-shape TiO2 particles filled EREs shows higher storage modulus G′ and higher relative ER effect within the electric field from 0 to 3 kV/mm. The observations indicate the use of rod-shape TiO2 particles in the form of brookite phase may help enhance the ER properties of elastomers. The investigation contributes to the designing, preparation, and application of anisotropic ERE.

A trivalent ferrite ferrofluid compound’s rheological response to angular frequency, magnetic induction and shear induction of chain clusters

At low and high temperatures in the presence and absence of magnetic fields, the effects of shear rate, angular frequency, and shear strain on the rheological characteristics of zinc ferrite ferrofluid is investigated. Chemical co-precipitation was used to create a zinc ferrite ferrofluid that was then coated with oleic acid to improve the stability of the fluid’s particles and avoid particle agglomeration. We looked at the rheological characteristics caused by the induced magnetic field, such as the shear stress, complex viscosity, storage modulus, loss modulus, relaxation modulus, viscous torque, damping factor, and figure of merit. From the analysis of time dependent relaxation modulus, a steady-state rheological system is formed at time interval beyond 50 s. As the shear and complex viscosities increase with an increase in magnetic field and a decrease in temperature, obstruction to fluid flow is produced. When a rheological system operates at low angular frequency and high shear rate, high shear stress is loaded; when it operates at high angular frequency and low shear rate, low shear stress is loaded. In the absence of magnetic field, a low viscosity 0.425 Pa.s and shear force 46 Pa were formed, while high viscosity 8.140 Pas and shear stress 168 Pa were formed when magnetic field 1.000 Tesla was applied. The oscillatory mode test demonstrates a change in structure from solid to liquid due to the establishment of a crossover point between shear strain 55 and 64%, supporting the solid–liquid phase transition behavior. The damping analysis demonstrates that the system is in fact excessively dampened, and it may now be utilized to reduce vibrations in a system. The system is really overdamped showing a maximum damping factor 2.08, according to the damping study, and can therefore be used to reduce vibrations in other systems. The fluid exhibits non-Newtonian shear-thinning behavior as shear rates increase. A high viscous torque is created at low shear strain and high angular frequency, which leads to the creation of a strong rotating magnetic field.

Breathable and impact-resistant shear thickening gel based three-dimensional woven fabric composites constructed by an efficient weaving strategy for wearable protective equipment

External low-velocity impacts (LVI) inevitably endanger human body health, yet attaining wear comfort and impact resistance simultaneously in protective equipment is challenging. Herein, flock-reinforced shear thickening gel (FRSTG) was demonstrated to display exceptional shear thickening behavior above the critical shear frequency (80.5 Hz). Three-dimensional (3D) shaped woven fabrics with folded structures were efficiently realized on a modified loom assembled with double warp beams and asynchronous self-reversal let-off systems, then 3D FRSTG/woven fabric composites were manufactured through a facile inclusion procedure. The “sizing effect” of FRSTG on the yarns resulted in enhanced mechanical properties of the composites. Attributed to the folded structures, the composites exhibited desired flexibility and innovatively achieved breathability (79.473 mm/s). They also performed responsive LVI resistance owing to the shear thickening effect of FRSTG and structural advantages of 3D shaped woven fabric. Furthermore, wearable protective applications based on those composites were evidenced to integrate breathability and LVI resistance.

Shock wave mitigation and impact resistance response of kevlar fabric with novel shear-stiffening gel core

A novel shear thickening gel with micro-scale hard/soft interface structure and low reaction temperature was proposed in this article. The gel was named TH and used as core material within Kevlar fabrics. Storage modulus of TH was proved to increase by around two orders with increasing of shear frequency, and dynamic properties indicated that TH could dissipate or store more energy. TH can adhere with Kevlar fabrics well and satisfactorily fulfill the gap between fabrics. As a result, shock wave peak pressure and positive impulse decreased markedly. Wavelet decomposition analysis show that high frequency energy was filtered by protection materials. Meanwhile, impact resistance test suggested the existence of TH changed the stress propagation routes and avoided pulling out for Kevlar fabrics. Samples filled with TH demonstrated a better shock wave mitigation ability and impact resistance. Energy dissipation structures with TH have a promising prospect in the application of defending area.

Development and Characterization of CO2-Responsive Intelligent Polymer Sealant.

In this study, we present an innovative intelligent polymer sealant designed to mitigate CO2 leakage during underground geological storage (CCUS). This sealant is formulated by cross-linking CO2-responsive polymers, specifically acrylamide (AM) and N-[3-(dimethylamino) propyl] methacrylamide (DMAPMA), with polyethylenimine (PEI) serving as the cross-linking agent. The polymer sealant's characteristics were systematically investigated, varying the CO2-responsive polymer content (1.5 wt %) and PEI content (0.1-0.6 wt %). A comprehensive analysis encompassing the rheological properties, thermal behavior, conductivity, and microstructures was conducted. Experimental results indicate that the polymer sealant exhibits excellent injectability, rapid response kinetics, thermal stability, and robust mechanical strength. Upon encountering CO2, the polymer system undergoes a transition from sol to gel state, forming a surface-smooth, uniformly porous three-dimensional (3D) network skeleton structure. Remarkably, the gel's modulus remains relatively unaffected by the shear frequency. Core fluid displacement experiments demonstrated a substantial sealing efficiency of 73.6% for CO2 and an impressive subsequent injection water sealing rate of 96.2%, underscoring its superior sealing and migration performance. In conclusion, the proposed CO2-responsive gel sealant exhibits an exceptional potential for successful utilization in CCUS operations. This advancement introduces a novel avenue to enhance the effectiveness of CO2-responsive gel sealants, thereby contributing to the advancement of CO2 leakage mitigation strategies in geological storage scenarios.