Search Results (1,035)

This study investigated the physicochemical and rheological properties of floury rice powder (FRP) with different particle sizes and their effects on the quality characteristics of gluten-free butter sponge cake. Soft rice grain (Baromi2 variety) was dry-milled and sieved into four fractions: FR1 (60 mesh overs), FR2 (60–80 mesh), FR3 (80–100 mesh), and FR4 (100 mesh throughs). FRP fractions were analyzed for chemical composition, swelling power, solubility, gelatinization, pasting viscosity, and viscoelastic property. Gluten-free cakes made using a whole-egg foam method were evaluated for morphological structure, baking loss, moisture, specific volume and firmness. With decreasing FRP particle size, there were increasing trends in solubility, pasting viscosity, resistance to deformation, viscoelastic attributes (G′ and G″), and gel rigidity. FR3 and FR4 cakes exhibited flat and puffy loaves compared to FR1 and FR2 cakes with loaf collapses. The finer FRP enhanced the morphological balances of the cakes. Increasing trends in specific volume and firmness were observed as FRP particle size decreased. These results paralleled the solubility, pasting, rheological, and gelling properties of FRP itself. Overall, the results suggest that the rheological and gelling properties of FRP may play a role in determining the quality of gluten-free sponge cakes. In addition, FRP with a particle size of 80–100 mesh appears most appropriate for gluten-free sponge cake. Full article

Enriching bread with functional ingredients is a promising strategy to enhance the nutritional and bioactive profile of widely consumed foods. This study evaluated partial substitution of wheat flour (WF) with chestnut flour (CF) and rosehip powder (RP) on bread nutritional quality, functionality, and rheology. Five bread formulations were developed by replacing WF with CF at 0%, 5%, 10%, 15%, and 20%. Four other formulations were prepared by replacing WF in the 15% CF sample with RP at 0.5%, 1%, 2%, and 3%. Proximate composition, total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (DPPH and FRAP), and key physical characteristics were assessed, alongside the retention rates of functional attributes after baking. Rheological behavior of composite flours was analyzed using the MIXOLAB system to evaluate dough performance. Results showed that moderate WF substitution with CF (5–15%) increased dietary fiber and antioxidant activity while maintaining acceptable dough rheology and bread quality. At 20% CF substitution, TPC, TFC, FRAP, and DPPH increased 1.62-, 1.63-, 2.93-, and 3.03-fold versus control, with 59–66% retention. Addition of RP up to 3% to the 15% CF-substituted sample further enhanced bioactive properties, with TPC, TFC, FRAP, and DPPH reaching 2.13-, 2.03-, 4.49-, and 3.99-fold vs. BCF15, while retaining 61–67% of their functionality. Further inclusion of RP up to 2% in the 15% CF formulation maintains acceptable dough and bread performance, while 3% RP maximizes phytochemical enrichment but slightly affects technological properties. The combination of 15% CF and 2% RP provided a balanced enhancement in bioactive content and technological performance, offering a practical approach for producing functional bread with improved nutritional and technological attributes. Full article

This study investigates the effects of air pressure, glue pressure, and viscosity on atomization characteristics through experimental and simulation methods, aiming to reveal gas–liquid interaction mechanisms and optimize process parameters. The rheological parameters of aqueous polyurethane adhesives with varying viscosities were characterized. Spray characteristics, including spray angle, cured film diameter, and thickness, were quantitatively measured under different operating conditions. The internal flow field and droplet dynamics were numerically analyzed. The results indicate the following: Increasing the air pressure (from 0.3 to 0.7 MPa) enlarges the spray angle and film diameter while reducing the film thickness. In contrast, increasing the glue pressure enlarges all three parameters: spray angle, film diameter, and film thickness. Furthermore, increasing the viscosity within the test range reduces the spray angle, film diameter, and film thickness. These effects stem from enhanced gas kinetic energy and shear intensity (promoting liquid film fragmentation), an increased fluid flow rate with glue pressure, and strengthened droplet resistance to breakup with suppressed spreading at higher viscosities. This research provides useful criteria for nozzle design and the optimization of industrial atomization processes involving non-Newtonian adhesives. Full article

To investigate the mechanism by which the rheological properties of drilling fluids affect the stability of the wellbore in brittle mud shale, this study systematically examines the influence of drilling fluids with different rheological properties on the hydration dispersion and rock strength of brittle mud shale through a series of laboratory experiments, including thermal rolling tests and uniaxial compressive strength tests on core samples. The results reveal that for weakly dispersible brittle mud shale, the rheological properties of drilling fluids have a minor effect on hydration dispersion, with rolling recovery rates consistently above 90%. However, the rheological properties of drilling fluids significantly influence the strength of brittle mud shale, and this effect is coupled with multiple factors, including rock fracture intensity index, soaking time, and confining pressure. Specifically, as the viscosity of the drilling fluid increases, the reduction in rock strength decreases; for instance, at 5 MPa confining pressure with an FII of 0.46, the strength reduction after 144 h was 69.8% in distilled water (from an initial 133.2 MPa to 40.2 MPa) compared to 36.3% with 3# drilling fluid (from 133.2 MPa to 88.7 MPa, with 100 mPa·s apparent viscosity). Both increased soaking time and confining pressure exacerbate the reduction in rock strength; a 5 MPa confining pressure, for example, caused an additional 60.9% strength reduction compared to 0 MPa for highly fractured samples (FII = 0.46) in distilled water after 144 h. Rocks with higher fracture intensity indices are more significantly affected by the rheological properties of drilling fluids. Based on the experimental results, this study proposes a strength attenuation model for brittle mud shale that considers the coupled effects of fracture intensity index, soaking time, and drilling fluid rheological properties. Additionally, the mechanism by which drilling fluid rheological properties influence the strength of brittle mud shale is analyzed, providing a theoretical basis for optimizing drilling fluid rheological parameters and enhancing the stability of wellbores in brittle mud shale formations. Full article

Viscoelastic relaxation time and frequency spectra are useful for describing, analyzing, comparing, and improving the mechanical properties of materials. The spectra are typically obtained using the stress or oscillatory shear measurements. Over the last 80 years, dozens of mathematical models and algorithms were proposed to identify relaxation spectra models using different analytical and numerical tools. Some models and identification algorithms are intended for specific materials, while others are general and can be applied for an arbitrary rheological material. The identified relaxation spectrum model always depends on the identification method applied and on the specific measurements used in the identification process. The stress relaxation experiment data consist of the sampling times used in the experiment and the noise-corrupted relaxation modulus measurements. The aim of this paper is to build a model of the spectrum that asymptotically does not depend on the sampling times used in the experiment as the number of measurements tends to infinity. Broad model classes, determined by a finite series of various basis functions, are assumed for the relaxation spectra approximation. Both orthogonal series expansions based on the Legendre, Laguerre, and Chebyshev functions and non-orthogonal basis functions, like power exponential and modified Bessel functions of the second kind, are considered. It is proved that, even when the true spectrum description is entirely unfamiliar, the approximate sampling-times-independent spectra optimal models can be determined using modulus measurements for appropriately randomly selected sampling times. The recovered spectra models are strongly consistent estimates of the desirable models corresponding to the relaxation modulus models, being optimal for the deterministic integral weighted square error. A complete identification algorithm leading to the relaxation spectra models is presented that requires solving a sequence of weighted least-squares relaxation modulus approximation problems and a random selection of the sampling times. The problems of relaxation spectra identification are ill-posed; solution stability is ensured by applying Tikhonov regularization. Stochastic convergence analysis is conducted and the convergence with an exponential rate is demonstrated. Simulation studies are presented for the Kohlrausch–Williams–Watts spectrum with short relaxation times, the uni- and double-mode Gauss-like spectra with intermediate relaxation times, and the Baumgaertel–Schausberger–Winter spectrum with long relaxation times. Models using spectrum expansions on different basis series are applied. These studies have shown that sampling times randomization provides the sequence of the optimal spectra models that asymptotically converge to sampling-times-independent models. The noise robustness of the identified model was shown both by analytical analysis and numerical studies. Full article

Warm-mix foamed polyurethane modified bitumen (WPB) has been widely promoted due to its significant warm-mix effect and high viscosity. However, it still has problems such as too fast foam dissipation and unstable performance. Waste molecular sieves have an extremely fine pore structure that can absorb moisture. The porous characteristics of waste molecular sieves are used to adsorb water and let it slowly release water in bitumen. If the foam dissipation time can be prolonged and the bitumen expansion speed can be reduced, it will help to stabilize the performance of foamed bitumen. This paper conducts a study on the foaming characteristics and rheological properties of WPB based on waste molecular sieves. First, the bitumen foaming test is used to analyze the foaming characteristics of WPB with waste molecular sieves. Second, the basic properties of warm-mix foamed polymer-modified bitumen, including penetration, softening point, ductility, and viscosity, are investigated. Finally, a dynamic shear rheometer (DSR) is employed to study the high-temperature rutting resistance and high-temperature permanent deformation resistance of warm-mix foamed polymer-modified bitumen. The research results show that the amount of foaming water is the primary factor influencing bitumen foaming. The addition of waste molecular sieves has a significant impact on the intensity and duration of the bitumen foaming reaction. WPB with waste molecular sieves has a greater consistency and better high-temperature performance, but its low-temperature performance is somewhat weakened. The high-temperature deformation resistance of WPB with waste molecular sieves is superior to that of ordinary WPB and is affected by the amount of foaming water. An appropriate amount of foaming water can enable WPB with waste molecular sieves to exhibit excellent high-temperature deformation resistance. Full article

Mineral oil-based lubricants contain harmful elements, such as sulfur and phosphorus, pose significant harm to the environment. In current research on the application of waste oils and fats in bio-based lubricants, most studies focus on single pretreatment processes or additive preparation, lacking systematic investigations into the combined use of composite pretreatment and additives on lubricant performance. Moreover, the decolorization efficiency of traditional physical adsorption methods for treating waste oils and fats is limited, making it difficult to meet the raw material requirements for bio-based lubricants. The purpose of this study is to conduct composite pretreatment processes on waste oils and fats, understand the impacts of parameters such as additive dosage and environmental factors on lubricant performance, establish an environmentally friendly and performance-compliant preparation process for bio-based lubricants, and provide a theoretical basis and technical support for its industrial application. Recent studies have shown that new decolorization processes for waste oil treatment significantly improve decolorization and recovery rates, as evidenced by research comparing new and traditional methods. Pretreatment with hydrogen peroxide, activated clay, and activated carbon significantly improved the color and odor of treated waste oil, meeting standards for bio-based lubricant production. The intercalation polymerization reaction between ethyl cellulose (EC) and montmorillonite (MMT) was employed to develop an additive (CTAB-MMT/KH560-EC). A thorough investigation was performed to analyze the impact of temperature, processing time, and additive concentration on the rheological behavior. The bio-based lubricant exhibited a kinematic viscosity of 200.3 mm²/s at 40 °C and 28.3 mm²/s at 100 °C, meeting the standard conditions as outlined in ASTM D2270-10e1. This lubricant achieved an improved low-temperature performance with a pour point of −22 °C, a friction coefficient of 0.081, and an average pitting diameter of 0.94 mm, indicating its suitability for a range of applications. These lubricants exhibit outstanding viscosity characteristics, meeting the relevant requirements for energy and environmental applications in green, eco-friendly, and biodegradable sustainable development strategies while expanding their application scope. Full article

Recycled coarse aggregates (RCA) offer an alternative to natural coarse aggregates in concrete production, reducing natural aggregate extraction and landfill burdens and potentially lowering embodied energy and CO₂ emissions. This study leverages machine learning algorithms to predict the dynamic yield stress (DYS) and plastic viscosity (PV) of RCA concrete (RCAC). A database of 380 RCAC mixtures, incorporating 11 input features, was analyzed using six machine learning models: Artificial Neural Network (ANN), Decision Tree (DT), Random Forest (RF), Extreme Gradient Boosting (XGBoost), Light Gradient Boosting Machine (LightGBM), and Support Vector Machine (SVM). The model performance was compared, followed by sensitivity analyses to identify critical factors influencing DYS and PV. For DYS, the DT model demonstrated the highest predictive performance (testing R²/RMSE/MAE = 0.95/18.25/13.99; others: 0.90–0.93/12.14–26.10/15.40–19.50) due to its robustness on smaller datasets. The XGBoost model led for PV (testing R²/RMSE/MAE = 0.93/7.06/4.58; others: 0.82–0.89/8.69–11.20/6.06–7.51) owing to its sequential residual minimization that captures nonlinear interactions. Sensitivity analyses revealed that polycarboxylate superplasticizer content and water-to-binder ratio significantly influence DYS, while cement content and saturated-surface-dried water absorption of RCA (i.e., measured with open pores filled and the aggregate surface dry) dominate PV. The time-dependent role in affecting PV was also highlighted. By optimizing and comparing different machine learning algorithms, this study advances predictive methodologies for the rheological properties of RCAC, addressing the underexplored use of machine learning for RCAC rheology (DYS and PV) and the limitations of traditional empirical rheology methods, thereby promoting the efficient use of recycled materials in sustainable concrete design. Full article

Silica-reinforced chitosan/collagen hydrogels are useful for biomedical applications. In this study, thermosensitive chitosan/collagen hydrogels were prepared with different amounts of rice husk ash-derived silica (RHA-Si). Fourier-transform infrared (FTIR) spectroscopy was used to analyze the chemical structure. Results showed that adding RHA-Si did not change the main chemical groups but caused slight shifts, indicating physical interactions. Micro-Computed Tomography (Micro-CT) revealed that RHA-Si altered the shape and size of the pores in the hydrogel. The pore structure became more spherical at certain RHA-Si levels, but not consistently. Rheological tests showed that increasing RHA-Si made the hydrogel stiffer and reduced the gelation time. However, the hydrogel weakened under high strain due to broken physical bonds. Compression tests indicated that low RHA-Si (1% w/v) improved the hydrogel’s strength during small deformations. In contrast, the hydrogel was less resistant to compression at higher RHA-Si levels (2–3% w/v). In summary, adding RHA-Si can improve the structure and strength of chitosan/collagen hydrogels, but excessive RHA-Si may reduce flexibility. The RHA-Si content should be adjusted to match the intended application of the hydrogel. Full article

In the mining industry, key unit operations such as grinding, flotation, thickening, and tailings transport are negatively affected by the presence of clay minerals, which impart complex rheological behaviors to mineral suspensions by increasing their rheological properties. This deterioration arises from specific physicochemical characteristics of clay minerals such as fine particle size, anisotropic character, laminar morphology, and swelling capacity. This work reviews the effects of various rheology-modifying reagents on clay suspensions including kaolinite, illite, and montmorillonite. The reviewed reagents include inorganic salts, pH modifiers, polymers, surfactants, and nanoparticles. Their mechanisms of interaction with solid particles are analyzed, highlighting their influence on the degree of dispersion or aggregation. Furthermore, this review proposes research opportunities focused on the formulation of hybrid reagents, modified biopolymers, and the development of reagents effective under adverse conditions such as high salinity or elevated temperatures. This review provides a comprehensive basis for optimizing the use of rheological additives through more efficient and sustainable strategies for managing clay-rich suspensions in the mining industry. Full article

Polymer-modified bitumen is difficult to produce and often separates during storage and transport. In contrast, granular bitumen modifiers offer wide applicability, construction flexibility, and ease of transport and storage. This study involved preparing a multipolymer granulated bitumen modifier with a styrene–butadiene–styrene block copolymer, polyethylene, and aromatic oil. To elucidate the modification mechanism of a multipolymer granulated bitumen modifier on bitumen, the elemental composition of bitumen A and B, the micro-morphology of the modifiers, the changes in functional groups, and the distribution state of the polymers in the bitumen were investigated using an elemental analyzer, a scanning electron microscope, Fourier-transform infrared spectroscopy, and fluorescence microscopy. The effects of the multipolymer granulated bitumen modifier on the physical, rheological, and viscoelastic properties of two types of base bituminous binders were investigated at various dosages. The test results show that the Z_H/C ratio of base bitumen A is smaller than that of base bitumen B and that the cross-linking effect with the polymer is optimal. Therefore, the direct-feed modified asphalt of A performs better than the direct-feed modified asphalt of B under the same multipolymer granulated bitumen modifier content. The loose, porous surface structure of styrene–butadiene–styrene block copolymer promotes the adsorption of light components in bitumen, and the microstructure of the multipolymer granulated bitumen modifier is highly coherent. When the multipolymer granulated bitumen modifier content is 20%, the physical, rheological, and viscoelastic properties of the direct-feed modified asphalt of A/direct-feed modified asphalt of B and the commodity styrene–butadiene–styrene block copolymer are essentially identical. While the multipolymer granulated bitumen modifier did not significantly improve the performance of bitumen A/B at contents greater than 20%, the mass loss rate of the direct-feed modified asphalt of A to aggregate stabilized, and the adhesion effect reached stability. Image processing determined the optimum mixing temperature and time for multipolymer granulated bitumen modifier and aggregate to be 185–195 °C and 80–100 s, respectively, at which point the dispersion homogeneity of the multipolymer granulated bitumen modifier in the mixture was at its best. The dynamic stability, fracture energy, freeze–thaw splitting strength ratio, and immersion residual stability of bitumen mixtures were similar to those of commodity styrene–butadiene–styrene block copolymers with a 20% multipolymer granulated bitumen modifier mixing amount, which was equivalent to the wet method. The styrene–butadiene–styrene block copolymer bitumen mixture reached the same technical level. Full article

In extended-reach wells, cuttings bed formation in high-deviation sections presents a major challenge for hole cleaning and borehole stability. This study analyzes the morphological and mechanical behavior of cuttings beds, focusing on particle size distribution and repose angle as key indicators of accumulation behavior. The modeling approach considers dominant interparticle forces, including buoyancy and cohesion, while neglecting secondary microscale forces for clarity. A theoretical model is developed to predict repose angles under both rolling and sliding regimes and is calibrated through laboratory-scale experiments using simulated drilling fluid with field-representative rheological properties. Results show that cohesive effects are negligible when cuttings are of similar size but exhibit higher densities. Laboratory measurements reveal that the repose angle of cuttings beds varies between 23.9° and 31.7°, with increasing polyacrylamide (PAM) concentration and particle size contributing to steeper repose angles. Additionally, the rolling repose angle is found to be relatively stable, ranging from 25° to 30°, regardless of fluid or particle property variations. These findings provide a predictive framework and practical guidelines for optimizing hole cleaning strategies and designing more effective models in extended-reach drilling. Full article

Bitumen ages during production and in asphalt pavements, leading to structural issues and reduced durability of asphalt pavements. The alteration of bitumen’s viscoelastic properties, predominantly attributable to oxidation phenomena, is a hallmark of these processes. This study analyzed the use of a new generation of synthetic wax (SW_LC), which was selected for its low carbon footprint, ability to reduce binder viscosity, and ability to enable the production of WMA. Tall oil amidopolyamines (TOAs), a renewable raw material-based adhesive and aging inhibitor, was also used in this study. It compensates for the unfavorable effect of stiffening the binder with synthetic wax. SW_LC at concentrations of 1.0%, 1.5%, 2.0%, and 2.5% by mass in bitumen, in conjunction with TOAs at concentrations of 0.0%, 0.2%, 0.4%, and 0.6% by bitumen weight were tested at various concentrations. Short-term and long-term aging effects on penetration, softening point, and viscosity multiple creep and stress recovery tests (MSCR), oscillatory tests for the combined complex modulus |G*| and phase shift angle sin(δ) (DSR), and low-temperature characteristics S_m and m_value (BBR) were analyzed. The chemical composition of the binders was then subjected to Fourier Infrared Spectroscopy (FTIR) analysis, which enabled the determination of carbonyl, sulfoxide, and aromaticity indexes. These results indicated that the additives used inhibit the oxidation and aromatization reactions of the bitumen components. The optimal SW_LC and TOA content determined was 1.5% and 0.4% w/w, respectively. These additives reduce aging and positively affect rheological parameters. Full article

The use of mining by-products in bitumen and asphalt mixture modification has drawn a lot of interest lately since it can improve pavement performance while advancing the goals of the circular economy and environmental sustainability. Mining by-products such as steel slag, red mud, silica fume, and fly ash have demonstrated good results as sustainable materials for improving the chemical, mechanical, durability, and rheological properties of asphalt binders and mixtures while also reducing the environmental degradation brought about by the disposal of these by-products. This study reviews research efforts on mining by-products (specifically steel slag, silica fume, red mud, and fly ash) in asphalt concrete pavement construction, analyzing the existing research, with emphasis on their various applications in asphalt concrete, their benefits as sustainable asphalt concrete materials, and limitations connected to their use. This review concludes by providing future directions in the utilization of these mining by-products in asphalt concrete production. This review contributes to the development of cost-effective, eco-friendly, and high-performance road construction materials, helping the transition to sustainable infrastructure. Full article

The recycling of polypropylene (PP) packaging films modified with biobased additives: biochar derived from the pyrolysis of natural fibers and diatomaceous earth was investigated. The aim was to assess the impact of these modifiers on the processing, rheological, mechanical, and thermal properties of the recycled material. The processing behavior was evaluated through extrusion with granulation to determine industrial applicability. Rheological properties, including viscosity and melt flow index (MFI), were measured to characterize flow behavior. Mechanical performance was assessed through tensile strength, hardness, three-point bending, and impact resistance tests. Thermal properties were analyzed using thermogravimetric analysis (TGA), Vicat softening temperature (VST), and differential scanning calorimetry (DSC). The results demonstrate that incorporating biochar and diatomaceous earth can modify and, in selected cases, enhance the processing and performance characteristics of recycled PP films, though their impact on thermal behavior is parameter-specific. While diatomaceous earth slightly increased the onset of thermal degradation (T₅), both fillers caused a slight decrease in the VST, indicating reduced heat resistance under load. Diatomaceous earth was found to effectively improve stiffness and impact strength, while biochar reduced viscosity and promoted finer crystalline structures. Both additives acted as nucleating agents, increasing crystallization temperatures, with diatomaceous earth additionally delaying thermal degradation onset. These findings highlight the potential of using sustainable, waste-derived additives in polymer recycling, supporting the development of environmentally responsible materials within circular economy frameworks. Full article