Rheological Properties Research Articles

Improved mechanical properties and fiber dispersion of limestone calcined clay cement (LC³) mortars by adjusting the mixing methods

An emerging cement, limestone calcined clay cement (LC³), reduces CO2 emissions by using less clinker in manufacture, promoting sustainability. Compared with OPC, LC³ binders (with the same water-to-binder ratio) show reduced flowability, leading to poor fibre dispersion in the matrix. This paper attempts to improve the flowability by adding different amounts of superplasticizer and using an innovative two-phase water addition (TPWA) mixing approach. This method focuses on adjusting the amount of water addition in the first phase to improve the fibre distribution while maintaining the total water addition for all mixtures. Results show that modified mixing strategies improve the fresh and hardened characteristics of LC³ mortars. As the amount of water addition (in the first phase) decreases, the yield strength increases while the plastic viscosity of mortars decreases. The high yield stress is associated with high fibre segregation resistance during the compaction. The low plastic viscosity is related to high fibre mobilizability during mixing, preventing fibres from clustering. As a result, the humongous mixture and the best mechanical performance was achieved when 83 % of the total water was added in the first phase, with a w/b ratio of 0.35. For the mixture with a w/b ratio of 0.38, the best mechanical properties were obtained when 68 % of the total water was added in the first stage. The relationships between rheological properties, fibre dispersion and mechanical properties of LC³ systems are also established.

Radio frequency drying on functional diversity of tiger nut flour: Effects on physicochemical, structural, and rheological properties

Tiger nut (TN) is a valuable nutrient and gluten-free tuber. To achieve high-quality TN flour as functional ingredients in food, it is essential to develop effective drying technologies for TN. Five drying methods including natural drying (Control), hot-air drying (HD), radio frequency single drying (RFSD), RF assisted hot-air drying (RFHD), and RF- vacuum drying (RFVD) were selected and compared to determine their effects on physiochemical, structural, and rheological properties of TN flour. Results showed that RF drying (RFD) significantly improved the hydration, oil-absorbing, and antioxidant activity capacity, especially for RFVD. RFHD exhibited greater color (BI = 13.80 ± 0.05 and C = 10.26 ± 0.05) and reducing sugar content (253.50 ± 2.27 mg d.b.) than RFSD and RFVD. The gelatinization temperature, enthalpy value, and particle size (57.30–269.33 μm) of TN flour were reduced. The structural property results indicated that RFD reduced the relative crystallinity and short-range ordering of the flour, altered protein secondary structure, and caused the damaged microstructure in comparison with Control and HD groups. All sample gels exhibited a weak strain overshoot behavior (type III) under large amplitude oscillations, and RFD resulted in a reduced viscoelastic behavior. RFD could be an effective method to produce functional TN flour.

Effects of Incorporating Ionic Crosslinking on 3D Printing of Biomass–Fungi Composite Materials

Biomass–fungi composite materials primarily consist of biomass particles (sourced from agricultural residues) and a network of fungal hyphae that bind the biomass particles together. These materials have potential applications across diverse industries, such as packaging, furniture, and construction. 3D printing offers a new approach to manufacturing parts using biomass–fungi composite materials, as an alternative to traditional molding-based methods. However, there are challenges in producing parts with desired quality (for example, geometric accuracy after printing and height shrinkage several days after printing) by using 3D printing-based methods. This paper introduces an innovative approach to enhance part quality by incorporating ionic crosslinking into the 3D printing-based methods. While ionic crosslinking has been explored in hydrogel-based bioprinting, its application in biomass–fungi composite materials has not been reported. Using sodium alginate (SA) as the hydrogel and calcium chloride as the crosslinking agent, this paper investigates their effects on quality (geometric accuracy and height shrinkage) of 3D printed samples and physiochemical characteristics (rheological, chemical, and texture properties) of biomass–fungi composite materials. Results show that increasing SA concentration led to significant improvements in both geometric accuracy and height shrinkage of 3D printed samples. Moreover, crosslinking exposure significantly enhanced hardness of the biomass–fungi mixture samples prepared for texture profile analysis, while the inclusion of SA notably improved cohesiveness and springiness of the biomass–fungi mixture samples. Furthermore, Fourier transform infrared spectroscopy confirms the occurrence of ionic crosslinking within 3D printed samples. Results from this study can be used as a reference for developing new biomass–fungi mixtures for 3D printing in the future.

Comparison of thermal, rheological properties of Finnish Pinus sp. and Brazilian Eucalyptus sp. black liquors and their impact on recovery units

Black liquor (BL) is the major bioproduct and biomass fuel in pulp mill processes. However, the high viscosity of BL makes it a challenging material to work with, resulting in issues with evaporators and heat exchangers during its transport and processing. The thermal and rheological properties of BLs from Pinus sp. (PBL) and Eucalyptus sp. (EBL) were studied. FTIR spectra revealed the presence of the characteristic functional groups and the chemical composition in liquors. TGA/DTG curves showed three characteristic degradation stages related to evaporation of water, pyrolysis of organic groups, and condensation of char. Rheologically, liquors are classified as non-Newtonian and with comportment pseudoplastic. Their rheological dynamic shear properties included a linear viscoelastic region up to 1% shear strain, while frequency sweeps showed that storage modulus (Gʹ) > loss modulus (Gʹʹ), thus confirming the solid-like behavior of both BLs. The rheological study demonstrated that increasing the temperature and oscillatory deformations of PBL and EBL decreased their degree of viscoelasticity, which could favor their pumping and handling within the pulp mill, as well as the droplet formation and swelling characteristics in the recovery furnace.

Ultrasonic-assisted preparation of SBS modified asphalt: Cavitation bubble numerical simulation and rheological properties

SBS (styrene–butadiene–styrene block copolymer) is currently the most widely used asphalt modifier, and SBS modified asphalt is usually prepared by high-speed shearing. This paper combines the cavitation effect of ultrasonic to assist in the preparation of SBS modified asphalt, and conducts numerical simulation and rheological properties research on the cavitation bubbles in the molten SBS modified asphalt fluid. The cavitation bubbles in the modified asphalt fluid will expand and contract as the pressure changes inside and outside the bubbles. When the cavitation bubble is compressed to the minimum and the pressure inside the bubble reaches 1.94 × 105Pa, the direction of the velocity vector near the cavitation bubble will change with the expansion and compression of the bubble. The expansion–contraction process of a single cavitation bubble can release 6.41 × 10-7J of energy, thus breaking the long bonds in asphalt and generating a large number of free radicals react with the unsaturated C = C bonds in the SBS molecules. According to the preparation process of modified asphalt, the influence of ultrasonic wave on rheological property of modified asphalt was studied through experiments. The results show that ultrasonic treatment can enhance the elasticity of asphalt and improve the temperature sensitivity of asphalt. With the increase of ultrasonic treatment time, the anti-rutting deformation ability of SBS modified asphalt is greatly improved. At the same temperature, the recovery rate of asphalt also increases with the increase of ultrasonic treatment time, and the non-recoverable compliance (Jnr) decreases Combined with the numerical simulation of cavitation bubbles, the ultrasonic process is added to asphalt production, which is of great significance for the green production of modified asphalt and the improvement of the rheological properties of modified asphalt.

Cure State Sensing of Polymethylmethacrylate Using a Vibrating Axial Probe.

A new axially vibrating sensor based on an audio voice coil transducer and a lead zirconate titanate (PZT) piezoelectric disc microphone was developed as a probe for the measurement of in vitro rheological fluid properties, including curing progress for polymethylmethacrylate (PMMA) mixtures with important uses as bone cement in the field of orthopedics. The measurement of the vibrating axial sensor's acoustic spectra in PMMA undergoing curing can be described by a damped harmonic oscillator formalism and resonant frequency (ca. 180 Hz) shift can be used as an indicator of curing progress, with shifts to the blue by as much as 14 Hz. The resonant frequency peak was measured in 19 different 4.0 g PMMA samples to have a rate of shift of 0.0462 ± 0.00624 Hz·s-1 over a period of 400 s while the PMMA was in a dough state and before the PMMA transitioned to a hard-setting phase. This transition is unambiguously indicated by this sensor technology through the generation of a distinct circa 5 kHz high-Q under-damped ring-down response.

Comparison of four rheological models for estimating viscosity and rheological parameters of microwave treated Basil seed gum

Dispersion of Basil seed gum has high viscosity and exhibits shear-thinning behavior. This study aimed to analyze the influence of microwave treatment (MT) at various time intervals (0, 1, 2, and 3 min) on the viscosity and rheological behavior of Basil seed gum dispersion (0.5%, w/v). The finding of this study revealed that the apparent viscosity of Basil seed gum dispersion (non-treated dispersion) reduced from 0.330 Pa.s to 0.068 Pa.s as the shear rate (SR) increased from 12.2 s−1 to 171.2 s−1. Additionally, the apparent viscosity of the Basil seed gum dispersion reduced from 0.173 Pa.s to 0.100 Pa.s as the MT time increased from 0 to 3 min (SR = 61 s−1). The rheological properties of gum dispersion were successfully modeled using Power law (PL), Bingham, Herschel–Bulkley (HB), and Casson models, and the PL model was the best one for describing the behavior of Basil seed gum dispersion. The PL model showed an excellent performance with the maximum r-value (mean r-value = 0.942) and the minimum sum of squared error (SSE) values (mean SSE value = 5.265) and root mean square error (RMSE) values (mean RMSE value = 0.624) for all gum dispersion. MT had a considerable effect on the changes in the consistency coefficient (k-value) and flow behavior index (n-value) of Basil seed gum dispersion (p < 0.05). The k-value of Basil seed gum dispersion decreased significantly from 3.149 Pa.sn to 1.153 Pa.sn (p < 0.05) with increasing MT time from 0 to 3 min. The n-value of Basil seed gum dispersion increased significantly from 0.25 to 0.42 (p < 0.05) as the MT time increased. The Bingham plastic viscosity of Basil seed gum dispersion increased significantly from 0.029 Pa.s to 0.039 Pa.s (p < 0.05) while the duration of MT increased. The Casson yield stress of Basil seed gum dispersion notably reduced from 5.010 Pa to 2.165 Pa (p < 0.05) with increasing MT time from 0 to 3 min.

The Rejuvenation Effect of Bio-Oils on Long-Term Aged Asphalt.

Generally, rejuvenators are used to supply missing components of aged asphalt, reverse the aging process, and are widely used in asphalt maintenance and recycling. However, compared with traditional rejuvenators, bio-oil rejuvenators are environmentally friendly, economical and efficient. This study looks into the effect of the three different bio-oils, namely sunflower oil, soybean oil, and palm oil, on the physical properties, rheological properties and chemical components of aged asphalt at different dosages. The asphalt physical properties and Dynamic Shear Rheological (DSR) test results show that with the increase in bio-oil, the physical properties and rheological properties of rejuvenated asphalt are close to those of virgin asphalt, but the high-temperature rutting resistance needs to be further improved. The results of Fourier Transform Infrared Spectroscopy (FTIR) show that the carbonyl and sulfoxide indices of rejuvenated asphalt are much lower than those of aged asphalt. Moreover, the rejuvenation efficiency of aged asphalt mixed with sunflower oil is better than that with soybean oil and palm oil at the same dosage.

The Rejuvenation Effect of Bio-Oils on Long-Term Aged Asphalt

Generally, rejuvenators are used to supply missing components of aged asphalt, reverse the aging process, and are widely used in asphalt maintenance and recycling. However, compared with traditional rejuvenators, bio-oil rejuvenators are environmentally friendly, economical and efficient. This study looks into the effect of the three different bio-oils, namely sunflower oil, soybean oil, and palm oil, on the physical properties, rheological properties and chemical components of aged asphalt at different dosages. The asphalt physical properties and Dynamic Shear Rheological (DSR) test results show that with the increase in bio-oil, the physical properties and rheological properties of rejuvenated asphalt are close to those of virgin asphalt, but the high-temperature rutting resistance needs to be further improved. The results of Fourier Transform Infrared Spectroscopy (FTIR) show that the carbonyl and sulfoxide indices of rejuvenated asphalt are much lower than those of aged asphalt. Moreover, the rejuvenation efficiency of aged asphalt mixed with sunflower oil is better than that with soybean oil and palm oil at the same dosage.

Enhancing Pavement Durability: Comparative Rheological Evaluation of Conventional and Rejuvenated Reclaimed Binders under Aging Conditions.

A drawback of recycled mixtures containing reclaimed asphalt is their increased stiffness, further worsened by the accelerated aging of binders in extreme weather conditions. Previous studies have shown that while rejuvenating agents can mitigate some of these issues by improving flexibility and reducing brittleness, they often present challenges, such as performance variability and the potential for rutting. This study aims to develop an optimal blend of reclaimed bitumen, a rejuvenating agent, and pure bitumen to achieve rheological properties similar to a control 35/50 pen-grade bitumen for road paving. Hence, the rejuvenated binders comprised 30:70 blends of reclaimed asphalt bitumen and 50/70 pen-grade bitumen, adding 0.2% to 0.6% of a rejuvenating agent by mass of the reclaimed asphalt. Sample testing included conventional penetration grade, softening point, and viscosity tests, followed by dynamic shear rheometer tests under unaged, short-term, and long-term aging conditions. The results show that the binder blend with 0.4% rejuvenator closely resembles the rheological properties of 35/50 pen-grade bitumen. This blend exhibits a 20% to 55% stiffness reduction for recycled mixtures with 30% reclaimed asphalt. Notably, the rejuvenated binders exhibited a similar level of aging resistance to the control bitumen, with a marginal difference of less than 5% in aging ratios. Meanwhile, large strain amplitude tests showed the importance of defining maximum rejuvenating incorporation rates in recycled mixtures to avoid rutting problems, where binders with 0.4% rejuvenator doubled the rutting potential (Jnr values). This innovative study highlights the potential for enhancing recycled mixtures' performance by evaluating rejuvenated reclaimed binders' rheology subjected to different aging conditions, thus contributing to sustainability in pavement construction.

Effect of Modifiers on Self-Healing and Rheological Properties of Asphalt Binder.

The effects of four modifiers were studied to compare their roles in the self-healing ability of asphalt binder: elemental sulfur, with a known plasticizing effect; wax, containing long alkane chains (>C50) with a known crystallizing capability; a plastic oil, with short alkane chains (<C20); and a combination of the wax and plastic oil. The results indicated that the self-healing performance of asphalt binder was increased by each of the four modifiers at 25 °C. Sulfur provided the greatest improvement in self-healing capacity, followed by plastic oil, wax combined with plastic oil, and then wax. This was attributed to sulfur's plasticizing effect, which is conducive to the self-diffusion of asphalt binder molecules. But at 40 °C, the wax, plastic oil, and wax + plastic oil modifiers weakened the self-healing capacity of asphalt binder, especially the wax modifier. In terms of percent recoverable strain, the asphalt binder modified by wax (long alkane chains) showed the highest percent recovery. The wax-modified asphalt binder also had the highest complex shear modulus compared to the other three modified binders and control binder. And its phase angle was lower than that of plastic oil-, sulfur-modified asphalt binder, and control binder.

Combined effects of nitrogen and sulfur fertilizers on chemical composition, structure and physicochemical properties of buckwheat starch

Buckwheat starch has attracted worldwide attention in the food industry as a valuable raw material or food additive. Nitrogen (N) and sulfur (S) are two nutrients essential to ensure grain quality. This study investigated the combined application of N fertilizer (0, 45 and 90 kg N ha−1) and S fertilizer (0 and 45 kg SO3 ha−1) on the chemical composition, structure and physicochemical properties of buckwheat starch. The results showed that increasing the fertilizer application decreased amylose content and starch granule size but increased light transmittance, water solubility and swelling power. The stability of the absorption peak positions and the decrease in short-range order degree suggested that fertilization influenced the molecular structure of buckwheat starch. In addition, increases in viscosity and gelatinization enthalpy as well as decreases in gelatinization temperatures and dynamic rheological properties indicated changes in the processing characteristics and product quality of buckwheat-based foods.

Application of mesoporous silica particles as an additive for controlling rheological, thermal, and filtration properties of water-based fluids

Mesoporous silica particles (MSP) have received increasing interest for various applications because of their unique features such as controlled pore size, low density, high chemical and thermal stability, and high surface area. In this study, MSP was applied as an additive in water-based drilling fluids (WBMs). The effect of MSP on the rheological, thermal, filtration, and structural properties of WBMs was investigated. The results were compared with those of analogous fluids containing conventional nonporous silica particles (SSP). Rheological assays showed shear-thinning and viscoelastic behavior, which were more noticeable for fluids including MSP. It was observed that low concentrations of MSP (0.25 %wt) can achieve the same rheological properties as the fluids with higher SSP content (up to 0.5 %wt). The rheological properties of SSP-containing fluids were not significantly affected by the presence of NaCl or aging tests. The theoretical Herschel–Bulkley model represents the rheological behavior of WBMs. The MSP-based WBMs exhibited better filtration properties before aging. The microstructures of the WBMs were analyzed using Scanning Electron Microscopy (SEM). A homogeneous distribution of SSP in the WBMs was observed, while particle agglomeration was observed in WBMs containing MSP. In addition, surface interactions were studied to elucidate the interactions between particles and fluid constituents. The surface interaction, assessed through ζ-potential and FTIR analysis, revealed that the binding affinities of BT, PAC, and XGD with MSP were augmented compared to their individual values. Based on the experimental results, MSP constitutes a promising alternative as an additive for the design of WBMs.

Thermal and rheological properties and processability of thermoplastic lignocellulose

AbstractFossil‐free biobased materials like thermoplastic lignocellulose are gaining attention because of climate issues. However, there is a challenge to make these as thermoplastic as commonly used thermoplastics. Arboform® is one of today's commercially available thermoplastic lignocellulose materials. In this work, the processability of this material was studied in detail and the effects of plasticizers on its processability, rheological, and mechanical properties were determined. Thermal/calorimetry analysis indicated that the processing temperature window was shifted to lower temperature with the use of tributyl citrate (TBC) and poly(ethylene glycol) (PEG 400) plasticizers, thus enabling extrusion at lower temperature. TBC and PEG 400 decreased both the glass transition temperature and melting point of the polylactide component. Surprisingly, they also affected the lignin component, as observed by the decreasing lignin decomposition temperature. It is observed that TBC and PEG400 lowered the stiffness of the compression molded material in the temperature range investigated (−30–180°C), and tensile tests in the presence of TBC revealed a decrease in ductility. Notable is that, in contrast to most thermoplastics, the Arboform® melt increases in viscosity and elastic moduli when the processing temperature was increased (from 180 to 200°C) or when processing time was increased.

Sensitivity Analysis Nusselt Number Correlation to Thermo Physical and Rheological Properties

We present the results of sensitivity analysis of thermo physical and rheological properties to temperature and concentration and hence sensitivity of Nusselt number to thermo physical and rheological properties. Sodium alginate which is a power law fluid has been used. Thermo physical and rheological properties were first measured experimentally and using RSM models has been developed as a function of temperature and concentration. Sensitivity of these developed models has been studied for temperature and concentration. From dimensional analysis it was found that Nusselt number depends on the thermo physical and rheological properties of power law fluids. Hence sensitivity of Nusselt number model has been studied for these properties. Studied thermo physical properties include density, surface tenson, specific heat and thermal conductivity. Rheological properties like consistency index and power law index have been studied. The sensitivity analysis indicates that properties, density, surface tension and specific heat are sensitive to temperature than concentration. Result for Nusselt number shows that model is very sensitive to specific heat, thermal conductivity and power law index

Characteristics of the Mixed Yogurt Fermented from Cow-Soy Milk in the Presence of Transglutaminase.

The mixed yogurt was fermented from Cow-Soy milk and modified by transglutaminase (TG). The effects of mixed milk and TG on the quality characteristics of mixed yogurt were investigated by texture characteristics, rheology (rheometer) and structure (scanning electron microscopy). The findings revealed that the mixed yogurt with 50% cow milk exhibited lower hardness, viscosity and consistency. Furthermore, when TG was added, the yogurt showed better rheological properties, sensory score and a more stable microstructure. Compared with the samples without TG modification, the viscosity and cohesiveness of the modified samples increased by 10% and 100%, respectively. The combination of cow milk and soy milk improved the texture of yogurt, and the TG addition further improved the physicochemical properties of yogurt. This finding provided a meaningful reference for the development of mixed yogurt with a suitable taste from animal and plant milk, and laid a basis for the practical application of mixed yogurt in the dairy industry, which will meet the requirements for dairy products for consumers in future.

A Rheological Study on the Effect of Tethering Pro- and Anti-Inflammatory Cytokines into Hydrogels on Human Mesenchymal Stem Cell Migration, Degradation, and Morphology.

Polymer-peptide hydrogels are being designed as implantable materials that deliver human mesenchymal stem cells (hMSCs) to treat wounds. Most wounds can progress through the healing process without intervention. During the normal healing process, cytokines are released from the wound to create a concentration gradient, which causes directed cell migration from the native niche to the wound site. Our work takes inspiration from this process and uniformly tethers cytokines into the scaffold to measure changes in cell-mediated degradation and motility. This is the first step in designing cytokine concentration gradients into the material to direct cell migration. We measure changes in rheological properties, encapsulated cell-mediated pericellular degradation and migration in a hydrogel scaffold with covalently tethered cytokines, either tumor necrosis factor-α (TNF-α) or transforming growth factor-β (TGF-β). TNF-α is expressed in early stages of wound healing causing an inflammatory response. TGF-β is released in later stages of wound healing causing an anti-inflammatory response in the surrounding tissue. Both cytokines cause directed cell migration. We measure no statistically significant difference in modulus or the critical relaxation exponent when tethering either cytokine in the polymeric network without encapsulated hMSCs. This indicates that the scaffold structure and rheology is unchanged by the addition of tethered cytokines. Increases in hMSC motility, morphology and cell-mediated degradation are measured using a combination of multiple particle tracking microrheology (MPT) and live-cell imaging in hydrogels with tethered cytokines. We measure that tethering TNF-α into the hydrogel increases cellular remodeling on earlier days postencapsulation and tethering TGF-β into the scaffold increases cellular remodeling on later days. We measure tethering either TGF-β or TNF-α enhances cell stretching and, subsequently, migration. This work provides rheological characterization that can be used to design new materials that present chemical cues in the pericellular region to direct cell migration.

Improved thermomechanical and rheological properties of polypropylene composites with thermomechanical pulp for injection molding

AbstractMaterial extrusion and injection molding are prevalent in polymer processing, but wood fiber‐reinforced polymer composites offer eco‐friendly alternatives for industries like automotive, and aviation. Our study explores biocomposites using bleached chemi‐thermomechanical pulp (BCTMP) and polypropylene (PP). BCTMP is rich in cellulose and hemicellulose and quite hydrophilic, while PP's hydrophobic structure creates a disconnect to creating a composite of the two. Traditional methods add costly coupling agents like maleic anhydride polypropylene (MAPP) in an attempt to enhance the adhesion properties of wood‐plastic composites. However, it is worth noting that even in the presence of MAPP, PP maintains its high hydrophobicity and low surface energy, despite exhibiting considerable heterogeneity. Further complexity arises from the thermal degradation characteristics of BCTMP during the melting processing of PP. Our proposed method involves premixing via cryo and planetary ball milling. This boosts PP and BCTMP adhesion, enhancing dispersion quality and mechanical properties without needing coupling agents. Moreover, the premixing of BCTMP and PP forms a thermal buffer layer around BCTMP, minimizing its thermal degradation during processing. This process also ensures even distribution of BCTMP into PP, resulting in a 200% rise in Young's modulus with 30 wt% BCTMP without compromising ultimate tensile strength.Highlights Exploration of biocomposites using bleached chemi‐thermomechanical pulp (BCTMP) and polypropylene (PP) thorough injection molding Implementation of premixing to enhance PP/BCTMP adhesion without coupling agents Premixing reduces thermal degradation of BCTMP, enhances dispersion, and improves mechanical properties Achieving a 200% increase in Young's modulus with 30% BCTMP incorporation, while maintaining ultimate tensile strength

Rheology characterization of ionic liquids under high pressure and high temperature

Ionic liquids (ILs) are liquid salts that exist at or below ambient temperatures and are composed of ion pairs. They offer promising alternatives to toxic, hazardous, highly flammable, and volatile solvents in various applications such as solution preparation, dispersion, gel formation, composites, and polymer melts. ILs possess unique and interesting characteristics, including excellent chemical and thermal stability and low vapor pressures. Understanding the rheological properties of ILs is essential to optimizing IL performance. This paper presents a comparative analysis of the rheological properties of two ionic liquids, NHexylpyridinium tetrafluoroborate (HPyBF4) and NHexylpyridinium bromide (HPyBr), under different shear rates, temperatures, and pressures. Rheological measurements were performed under varying controlled pressure and temperature conditions. The experimental investigation covered a pressure range of 689–12,411 kPa [100–1800 psi] and a temperature range from room temperature up to 522 kelvin (K) [480°F]. The primary objective is to explore and compare the flow behavior and viscoelastic characteristics of HPyBF4 and HPyBr under high-pressure and high-temperature conditions. The experimental data showed that HPyBF4 and HPyBr exhibited shear-thinning behavior, and pressure had an insignificant effect on rheology compared to the temperature effect. Under the same testing conditions, HPyBr showed higher shear stress and viscosity than HPyBF4. This research significantly contributes to the improved understanding of the rheological behavior of these specific ionic liquids and their suitability for diverse industrial and scientific applications, particularly in high-pressure and high-temperature environments.

The effect of fascial manipulation therapy on lower limb spasticity and ankle clonus in stroke patients.

Lower limb spasticity and clonus are common sequelae after cerebral stroke. An important part of their etiopathogenesis has been related to the peripheral component of spasticity. Rheological properties of the tissues seem to be involved. Several studies highlighted anatomical and functional changes in the connective structures. The fasciae might be implicated in the pathological process. Thus, this study intends to investigate the effect of the Fascial Manipulation (FM) technique on triceps surae in stroke patients through a clinical randomized controlled trial, to provide a reference for clinical treatment of lower limb spasticity and ankle clonus. A total of 40 patients with post-stroke ankle clonus were selected and divided into a control group and an observation group by random number table method, with 20 cases in each group. Both groups received conventional rehabilitation therapy, while the FM group received Fascial Manipulation based on conventional rehabilitation therapy. Before the first treatment and after 3 weeks of treatment, the Comprehensive Spasticity Scale (CSS), the Passive Range Of Motion (PROM), the simplified Fugl-Meyer motor function score (FMA), and the Modified Ashworth Scale (MAS) were used to assess the degree of ankle clonus, ankle passive range of motion, and lower limb motor function of the two groups of patients. Before treatment, there was no statistically significant difference between the control group and the FM group in terms of CSS, PROM, FMA, and MAS of the affected lower limbs (P>0.05). After 3 weeks of treatment, the CSS and MAS of the affected lower limbs in the control group and FM group decreased, while PROM and FMA increased compared to pre-treatment evaluation, with statistically significant differences (P<0.05). Moreover, the FM group showed a statistically significant decrease in CSS and MAS, as well as an increase in PROM and FMA, compared to the control group (P<0.05). Conclusions: Fascial manipulation in addition to conventional therapy can effectively reduce spasticity and ankle clonus in stroke patients in a short time, and improve the passive range of motion of the ankle joint and the function of lower limbs.