Temperature Sweep Research Articles

Performance assessment of microencapsulated phase change materials with low to high thermoregulation range in asphalt binder

ABSTRACT This study aims to assess the impact of microencapsulated phase change materials (MPCMs) on thermoregulation effect and binders’ performance. Accordingly, three MPCMs with melting points 6°C, 28°C, and 37°C were blended with PG 58-28 and PG 64-22 binders at dosages of 5%–20% by binder weight. Subsequently, laboratory experiments were conducted to examine impact on thermoregulation and rheological parameters including enthalpy change, complex modulus, Glover-Rowe parameter, creep stiffness, creep slope, fatigue, and rut factors. The findings showed that increasing MPCMs’ dosage in both control binders led to increased enthalpy change, indicating successful thermoregulation and capsules’ survival during blending. Rheological investigation depicted increasing complex modulus, creep stiffness and Glover-Rowe parameter in modified binders compared to control binders regardless of MPCMs’ thermoregulation range. However, Dynamic shear rheometer and Bending beam rheometer may not adequately capture their thermoregulation impact under steady-state conditions, necessitating use of temperature sweep test to validate influence on complex modulus and phase angle due to their thermoregulation capability. Temperature sweep test showed that within thermoregulation range, MPCMs with melting points 6°C and 28°C showed comparable fatigue resistance to respective control binders up to 10% dosage. Meanwhile, around melting point, MPCM with 37°C melting point enhanced rutting resistance.

Development and demonstration of a two-color nitric oxide vibrational temperature diagnostic using spectrally-resolved ultraviolet laser absorption

Development of a new ultraviolet (UV) laser absorption diagnostic has enabled the probing of nitric oxide (NO) in the second excited vibrational state (v” = 2) for inferences of quantum-state-specific number density and vibrational temperature time-histories. Spectroscopic modeling informed the selection of the new 246.3222 nm wavelength, as this wavelength exhibits high sensitivity for thermometry in the 2000 – 8000 K temperature range. This 246.3222 nm absorption feature consists of contributions from the R12(24.5), R11(15.5), Q22(24.5), and Q21(15.5) transitions all originating in the v” = 2 state. Absorption cross-sections at this selected wavelength were measured in reflected shock experiments for sweeps of both wavelength and temperature. The wavelength sweep investigated cross-sections over a 246.3202 – 246.3246 nm range at 4590 K, and the temperature sweep measured cross-sections over a 2500 – 7500 K range at the peak of the absorption feature (246.3222 nm). Cross-section results agree with the Stanford NO gamma-band model to within ±5%, confirming the use of the model for subsequent thermometry studies. Thermometry was demonstrated in reflected shock experiments probing the vibrational relaxation and chemical reactions in 2% NO diluted in either argon (Ar) or nitrogen (N2). These experiments leverage previous UV laser absorption diagnostics that probe NO in the ground vibrational state (v” = 0) using the R11(26.5), R12(34.5), Q21(26.5) , and Q22(34.5) transitions near 224.8155 nm and the Q11(12.5) , R12(19.5) , P21(12.5) , and Q22(19.5) transitions near 226.1026 nm, which were studied in Ref. [1]. The combination of the new diagnostic wavelength with previously validated diagnostics yields low-uncertainty vibrational temperature time-histories that are in excellent agreement with previously inferred vibrational relaxation time results from Refs. [2] and [3]. Future work will apply this two-color nitric oxide vibrational temperature diagnostic to probe the vibrational temperature of NO formed in high-temperature, shock-heated air at conditions relevant to hypersonic and reentry vehicles.

Innovative application of coffee grounds oil as an asphalt modifier: Extraction, preparation, and rheological properties

This study innovatively utilized coffee grounds oil (CGO) extracted from waste coffee grounds to modify base asphalt, aiming to promote sustainable reuse of coffee waste. The effects of modifier dosage, type, and aging conditions on the rheological properties of asphalt were investigated. After determining the extraction protocol, coffee grounds oil-modified asphalt (CGOA) and waste cooking oil-modified asphalt (WCOA) were prepared and subjected to short-term aging. Fourier transform infrared spectroscopy (FTIR) analyzed the modification mechanism, while temperature sweep, frequency sweep, bending beam rheometer, and multiple stress creep recovery (MSCR) tests assessed the rheological properties at high and low temperatures. Results showed that before aging, CGO improved thermal stability at medium to high temperatures and enhanced deformation and stress relaxation at low temperatures, though it reduced rutting resistance at high temperatures. After aging, CGOA with a dosage limited to 4 % exhibited rheological properties approaching base asphalt and improved the viscoelasticity of aged asphalt. In comparison, WCOA demonstrated significantly weaker performance, particularly after aging. This study provides practical insights into the novel application of CGO in pavement engineering.

Characterization of sacha inchi (Plukenetia volubilis) and taro (Colocasia esculenta) flours with potential application in the preparation of both gluten-free and high protein foods.

Background Interest in alternative sources of tubers and legumes has increased in recent years because of the constant search for raw materials that provide bioactive compounds with antioxidant potential benefits for consumers. The functionality of new raw materials is sought through physical and/or chemical modifications to develop and innovate new foods. The objective of this study was to characterize taro (TF) (Colocasia esculenta) and sacha inchi (Plukenetia volubilis) flours, obtained by the wet (SIF-WM) and defatted method (SIF-DM), as an alternative for the formulation of new functional foods. Methods The free polyphenols of the different mixtures were analyzed, and the antioxidant properties of the extracts obtained were measured using ABTS.* (2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid). The ABTS radical method, which reacts with the phenolic compounds of the food matrix, using Trolox as a standard. The blends were subjected to pasting analysis, flow profile tests, determination of viscoelastic properties (temperature sweep). Characterization of common microorganisms in these foods was performed. Results The highest protein value was obtained in the sacha inchi flour obtained by the defatted method (72.62%). The majority of components in taro were carbohydrates (85.4%). About antioxidant and determination of free polyphenols, taro flour obtained values of 2.71 μmol ET/g and 7.47 mg EAG/g, higher than sacha inchi flours. In the rheological analysis (pasting properties, flow profile, and viscoelasticity), we observed that adding taro flour in different mixtures increases the viscosity peak and a lower breakdown, while there was an increase in setback. Except for defatted sacha flour, the others presented a flow index >1 before heating, showing a dilatant fluid behavior. The presence of taro flour improves gel formation and stability. Staphylococcus aureus and Salmonella were present in the taro flour. Conclusions The flours analyzed represent a raw material with great potential for the development of products such as protein snacks due to the contribution of sacha inchi, with good expansion due to taro starch, and naturally gluten-free for people with celiac disease.

Electrical Characterization of a Large‐Area Single‐Layer Cu3BHT 2D Conjugated Coordination Polymer

AbstractUnderstanding charge transport properties of large‐area single‐layer 2D materials is crucial for the future development of novel optoelectronic devices. In this work, the synthesis and electrical characterization of large‐area single‐layers of Cu3BHT 2D conjugated coordination polymers are reported. The Cu3BHT are synthesized on the water surface by the Langmuir‐Blodgett method and then transferred to SiO2/Si substrates with pre‐patterned electrical contacts. Electrical measurements revealed ohmic responses across areas up to ≈1 cm2, with a mean resistance of approximately 53 ± 3 kΩ at a probe separation of 50 µm. Cooling and heating cycles show hysteresis in the electrical response, suggesting different current pathways are formed as the samples underwent structural‐chemical changes during temperature sweeps. This hysteresis vanished after several cycles and the conductivity shows a stable exponential behavior as a function of temperature, suggesting that a temperature‐dependent tunneling process is governing the conduction mechanism in the analyzed polycrystalline single‐layer Cu3BHT samples. These results, together with density functional theory calculations and valence band X‐ray photoelectron spectroscopy data suggest that the single‐layer samples exhibit a semiconducting rather than a metallic behavior.

Rheological, Thermal and Physicochemical Properties of Bioprocessed Flour From Cowpea, Sorghum and Orange Fleshed Sweet Potato

ABSTRACTThis study investigated the rheological, physicochemical, and thermal properties of fermented and germinated whole reddish‐brown cowpea, white sorghum and orange‐fleshed sweet potato. Germination substantially reduced the pasting and rheological attributes of flour suspensions compared to the fermentation process. This study observed notable increases in the hot paste, setback, and final viscosities after the fermentation of cowpea and sorghum, indicating an improvement in the ease of cooking and greater retrogradation tendency of starch molecules. Among the fermented flours, sorghum had the highest hot paste viscosity (848 mPa s) and final viscosity (1451 mPa s). The mechanical fingerprint revealed a viscoelastic solid character, with G′ > G″ over the frequency range of 0–10 rad/s for all samples. Temperature sweep data showed a sharp increase in G′ at about 80°C, corresponding to the onset of starch gelatinization. Shear‐thinning behavior was observed, except in germinated and raw sorghum flours, where molecular rearrangement resulted in an initial viscosity rise at a low share rate (< 20 s−1). Differential scanning calorimetric analysis revealed a marginal variation in the peak transition temperature of gelatinization (98°C–104°C for all flours except raw sorghum flour, 83.87°C). The fermented sweet potato flour indicated good flour particle flowability expressed as Carr's compressibility index (30.99) and the Hausner ratio (1.45); however, the available reducing sugars could have influenced its high percentage solubility (49.83%), thus impacting low pasting viscosities. The contrasting technological features suggest an avenue to intensify efforts in exploring composite bioprocessed flours for applications in novel foods.

Influence of Basalt Fiber Morphology on the Properties of Asphalt Binders and Mixtures.

Basalt fiber (BF) has been proven to be an effective additive for improving the properties of asphalt mixtures. However, the influence of basalt fiber morphology on the properties of asphalt binders and mixtures remains inadequately explored. In this study, chopped basalt fiber (CBF) and flocculent basalt fiber (FBF) were selected to make samples for testing the influence of the two types of basalt fibers on asphalt materials. Fluorescence microscopy was used to obtain the dispersion of fiber in asphalt binders. Then, a temperature sweep test and a multiple stress creep recovery (MSCR) test were carried out to appraise the rheological characteristics of the binder. Moreover, the performance of the fiber-reinforced asphalt mixture was evaluated by a wheel tracking test, a uniaxial penetration test, an indirect tensile asphalt cracking test (IDEAL-CT), a low-temperature bending test, a water-immersion stability test, and a freeze-thaw splitting test. The results indicate that the rheological behavior of asphalt binders could be enhanced by both types of fibers. Notably, FBFs exhibit a larger contact area with asphalt mortar compared to CBFs, resulting in improved resistance to deformation under identical shear conditions. Meanwhile, the performance of the asphalt mixture underwent different levels of enhancement with the incorporation of two morphologies of basalt fiber. Specifically, as for the road property indices with FBFs, the enhancement extent of DS in the wheel tracking test, that of RT in the uniaxial penetration test, that of the CTindex in the IDEAL-CT test, and that of εB in the low-temperature trabecular bending test was 3.1%, 6.8%, 15.1%, and 6.5%, respectively, when compared to the CBF-reinforced mixtures. Compared with CBFs, FBFs significantly enhanced the elasticity and deformation recovery ability of asphalt mixtures, demonstrating greater resistance to high-temperature deformation and a more pronounced effect in delaying the onset of middle- and low-temperature cracking. Additionally, the volume of the air void for asphalt mixtures containing FBFs was lower than that containing CBFs, thereby reducing the likelihood of water damage due to excessive voids. Consequently, the moisture susceptibility enhancement of CBFs to asphalt mixture was not obvious, while FBFs could improve moisture susceptibility by more than 20%. Overall, the impact of basalt fibers with different morphologies on the properties of asphalt pavement materials varies significantly, and the research results may provide reference values for the choice of engineering fibers.

Evaluation of the properties of high-content degraded crumb rubber–modified asphalt under thermal oxidation and weathering aging

In this study, the properties of high-content degraded crumb rubber–modified asphalt (HCDRA) under thermal oxidation and weathering aging were analyzed by the fluorescence microscopy test, temperature sweep test, zero shear viscosity test, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) test, and gel permeation chromatography (GPC) test. Morphological structure result shows that after various degrees of thermal oxidation and weathering aging, the number and size of crumb rubber (CR) particles in HCDRA became smaller. Besides, with the deepening of the degree of oxidization, the rutting resistance of HCDRA decreases firstly and then increases. The improvement of the anti-aging and temperature sensitivity of HCDRA is better than that of neat asphalt and 20 % content CR-modified asphalt. Moreover, thermal oxidation and weathering aging make HCDRA more sensitive to temperature, and the temperature sensitivity of HCDRA is more affected by long-term aging relative to neat asphalt and 20 % content CR-modified asphalt. ATR-FTIR test and GPC test show that the complex modulus of HCDRA increases with the increase of carbonyl groups after aging, and HCDRA becomes soft and then hard during the aging process with the increase of macromolecule polymer content. Lastly, cluster analysis and principal component analysis reveal that the degree of asphalt oxidation has a strong influence on failure temperature and zero shear viscosity, and small molecule polymer has a significant effect on the temperature sensitivity of rheological properties.

Assessing pavement characteristics: An in-depth evaluation of waste engine oil and Buton rock asphalt composite modified asphalt and its mixture

To investigate the cooperative influence of waste engine oil (WEO) and Buton rock asphalt (BRA) on asphalt characteristics, the WEO/BRA composite modified asphalt and its mixture with varied dosages were prepared. The high-, moderate-, and low-temperature assessments of WEO/BRA composite modified asphalt were conducted through temperature sweep tests, multiple stress creep and recovery (MSCR), and bending beam rheometer (BBR) tests. The softening point difference was used to analyze the storage stability of composite modified asphalt. Based on the Fourier transform infrared spectroscopy (FTIR) and fluorescence microscope (FM) test, the microscopic feature and chemical constitution of WEO/BRA composite modified asphalt were analyzed. Rutting test, low-temperature bending test, immersed Marshall test, freeze-thaw splitting test, and four-point fatigue bending test were carried out to verify the pavement properties of the WEO/BRA composite modified asphalt mixture. The results indicated that WEO improved the capability in low-temperature conditions and fatigue properties of asphalt modified with BRA. BRA enhanced the high-temperature property of asphalt modified with WEO. The synergistic effect of WEO, BRA, and neat asphalt was a physical reaction, and these modifiers were uniformly distributed in the asphalt. Meanwhile, WEO/BRA composite modified asphalt had excellent storage stability for the single modified asphalt. The test results of the asphalt mixture verified the results, indicating that WEO/BRA composite modified asphalt can be considered a new green and durable asphalt pavement material.

Performance evaluation of bio-oil and high rubber content modified asphalt: More effective waste utilization

In this study, the bio-oil was used to reduce the viscosity and preparation temperature of high content of rubber-modified asphalt. The high rubber content modified bio-asphalt (RMBA) was prepared, the rubber and bio-oil contents were 20 %-30 % and 5 %-15 % (mass ratio of neat asphalt), respectively. The viscosity, temperature sweep (TS), frequency sweep (FS), multi-stress creep recovery (MSCR), and bending beam rheometer (BBR) tests were performed to assess the properties of RMBA. The Fourier Transform infrared spectroscopy (FTIR), Fluorescence microscopy (FM), and Scanning electron microscope (SEM) tests were conducted to explore the microscopic morphology of RMBA. Besides, the economic analysis and life cycle assessment (LCA) were assessed. Bio-oil contributed to the viscosity-reduction of the RMBA. When the rubber content was 30 %, the viscosity decreased by 48.16 % with a bio-oil content of 15 %. The temperature and frequency sensitivity of RMBA were lower than neat asphalt. Rubber improved the creep recovery and anti-rutting deformation behavior for bio-asphalt. The absorption peaks appeared at 1010 and 1038 cm−1, which represented the SO function group. The rubber did not absorb enough bio-oil for solubilization. This resulted in the functional group of SO appeared in 30 %+B-10 % and R-30 %+B-15 %. FM and SEM test results indicated that the rubber in RMBA exists in different states: undissolved rubber and dissolved rubber. The high content rubber could be partially dissolved in bio-asphalt and retained its elastic properties. The dissolved rubber particles exhibited a large crosslinked network structure. The raw material cost of RMBA decreased significantly with the rise of rubber and bio-oil contents. The reasonable application of waste rubber is beneficial to the alleviation of black pollution. The efficient application of rubber and bio-oil could contribute to the development of waste utilization and green transportation.

Waste coffee biochar and bi-oil composite modified rejuvenated asphalt: Preparation, characterization, and performance evaluation

In the realm of sustainable road construction, bio-oil has emerged as a promising and eco-friendly alternative for rejuvenating aged asphalt. Nevertheless, challenges arise due to poor stability, diminished performance at elevated temperatures, and limited anti-aging properties. This study introduces an innovative approach by blending biochar, obtained from the pyrolysis of waste coffee grounds, into bio-oil to create a composite modified regenerator. Initially, the study conducts a microscopic characterization of the biochar using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Subsequently, the rheological properties of this composite rejuvenated asphalt are evaluated across low, moderate, and high-temperature ranges using bending beam rheometer (BBR), linear amplitude sweep (LAS), and multiple stress creep and recovery (MSCR) tests. Departing from the traditional emphasis on initial property restoration, it further delves into performance alterations after re-aging of rejuvenated asphalt through temperature sweep (TS) and Fourier transform infrared spectroscopy (FTIR) tests, providing a comprehensive assessment of the anti-aging characteristics of rejuvenated asphalt. Additionally, gel permeation chromatography (GPC) is employed to quantitatively analyze the changes in asphalt molecular weight distribution. The microscopic characterization reveals the development of a rough and porous structure within the biochar, facilitating enhanced adhesion and interaction between the rejuvenator and the asphalt binder. Moreover, bio-oil rejuvenated asphalt exhibits excellent low-temperature crack resistance and moderate-temperature fatigue resistance. Following the incorporation of biochar, notable enhancements in high-temperature rutting resistance and anti-aging properties are observed, validating the efficacy of the biochar with bio-oil composite modified regenerator. To achieve optimal performance outcomes, a biochar content of 6 % (as a proportion of aged asphalt), corresponding to a 1:1 ratio of biochar to bio-oil, is recommended. Under this condition, the properties of the composite modified rejuvenated asphalt demonstrate comparability to those of the original asphalt. In summary, this research underscores the potential for integrating waste coffee biochar material into infrastructure development, thereby promoting circular economy principles and advancing more sustainable construction practices.

A compact and tunable active inductor-based bandpass filter with high quality factor for Wireless LAN applications

A fully-differential compact and tunable second-order bandpass filter (BPF) with high quality factor using a novel active inductor (AI) has been proposed for 3.6 GHz WLAN applications. The proposed AI employs a differential amplifier as a feedforward transconductor and a common-source (CS) transistor as a feedback transconductor in a symmetrical configuration. The combination of a cascode scheme and a resistor in the feedback path enhances the quality factor of the AI, thereby increasing the mid-band gain of the BPF. In order to achieve independent tuning of both the center frequency and mid-band gain of the BPF, a varactor capacitor is utilized. The proposed second-order BPF is designed with a center frequency and a bandwidth of 3.675 GHz and 10 MHz, respectively. Post-layout simulation, process corner, and temperature sweep analysis results are conducted with 65 nm CMOS technology at 1.2 V supply voltage. The proposed filter has a tuning range of 3.655–3.695 GHz and attains a mid-band gain of 67.5 dB, a noise figure of 14.5 dB, and a 1-db compression point of −12.39 dBm. Additionally, the BPF consumes a DC power of 1.22 mW and occupies an active area of only 8.85 μm × 10.3 μm.

New insight into synergistic interaction between the backbone or side chain of xanthan gum and the backbone of Gleditsia sinensis polysaccharide

In this study, the synergistic effect and weak gel mechanism of XG and Gleditsia sinensis polysaccharide (GSP) in different ratios were studied through the rheological properties, microstructure and molecular simulation based on density functional theory (DFT). The results of rheological properties showed that the mixtures formed a weak gel at the concentration of 0.5 % (w/v), with the synergistic impact peaking at a XG/GSP ratio of 3:7. Weak gels produced by XG and GSP had the intersection of G' and G" within the temperature sweep range, and the largest change in the G' slope at a XG/GSP ratio of 3:7. By calculating the interaction energy, it was found that the backbone of XG was more likely to interact with the backbone of GSP. Furthermore, the XG mainchain intersected with the backbone of GSP in a cross shape (“X” shape). As a result, this paper proposed a possible mechanism for the formation of the XG/GSP weak gel, with XG as the main chain and GSP as the grid point, and the main interaction type being hydrogen bonding, with the van der Waals force also involved. The results provide new insight for designing and producing physical gels with specific interactions in food industry.

An Additive Manufacturing MicroFactory: Overcoming Brittle Material Failure and Improving Product Performance through Tablet Micro-Structure Control for an Immediate Release Dose Form.

Additive manufacturing of pharmaceutical formulations offers advanced micro-structure control of oral solid dose (OSD) forms targeting not only customised dosing of an active pharmaceutical ingredient (API) but also custom-made drug release profiles. Traditionally, material extrusion 3D printing manufacturing was performed in a two-step manufacturing process via an intermediate feedstock filament. This process was often limited in the material space due to unsuitable (brittle) material properties, which required additional time to develop complex formulations to overcome. The objective of this study was to develop an additive manufacturing MicroFactory process to produce an immediate release (IR) OSD form containing 250 mg of mefenamic acid (MFA) with consistent drug release. In this study, we present a single-step additive manufacturing process employing a novel, filament-free melt extrusion 3D printer, the MicroFactory, to successfully print a previously 'non-printable' brittle Soluplus®-based formulation of MFA, resulting in targeted IR dissolution profiles. The physico-chemical properties of 3D printed MFA-Soluplus®-D-sorbitol formulation was characterised by thermal analysis, Fourier Transform Infrared spectroscopy (FTIR), and X-ray Diffraction Powder (XRPD) analysis, confirming the crystalline state of mefenamic acid as polymorphic form I. Oscillatory temperature and frequency rheology sweeps were related to the processability of the formulation in the MicroFactory. 3D printed, micro-structure controlled, OSDs showed good uniformity of mass and content and exhibited an IR profile with good consistency. Fitting a mathematical model to the dissolution data correlated rate parameters and release exponents with tablet porosity. This study illustrates how additive manufacturing via melt extrusion using this MicroFactory not only streamlines the manufacturing process (one-step vs. two-step) but also enables the processing of (brittle) pharmaceutical immediate-release polymers/polymer formulations, improving and facilitating targeted in vitro drug dissolution profiles.

Assessment of various polymeric sulphur as soft bitumen improver for pavement applications

ABSTRACT In this study, five polymeric sulphurs are utilised, including polymeric sulphur based on both aliphatic copolymers and styrene copolymers, namely PS1 to PS5 correlated to amorphous poly alpha olefins (APAO) PS1, olefin residues from MAC carpet company PS2, Ethylene Vinyl Acetate (EVA) copolymer PS3, Styrene Butadiene Styrene (SBS) copolymer PS4 and Dicyclopentadiene monomer (DCPD) PS5. The five polymeric sulphur compounds were mixed by 25wt% with soft bitumen penetration grade (80/100) to produce five sulphur-extended asphalt binders, namely SEA1, SEA2, SEA3, SEA4, and SEA5. The physical properties, including softening point, viscosity, and penetration, are examined to characterise the consistency of SEA binder. The dynamic mechanical behaviour such as complex modulus, temperature sweep, and stress relaxation test was investigated for SEA binder and compared with a reference soft bitumen (Blank) using a dynamic mechanical analyzer (DMA). It is concluded that polymeric sulphur based on styrene compounds SEA2 and SEA4 binders have the highest resistance against cracking of the pavement at low temperatures according to penetration index readings, and have the least permanent (plastic) deformation at high temperatures according to temperature sweep from DMA data. It is noticed that SEA5 binder has a negative effect on the performance of soft bitumen.

Rheological and Aging Properties of Nano-Clay/SBS Composite-Modified Asphalt.

Nano-organic montmorillonite (OMMT) not only inhibits the harmful asphalt fume generation during the production and construction processes of asphalt mixtures but also effectively improves the performance of asphalt pavements. In order to prepare asphalt materials with smoke suppression effects and good road performance, this study selects nano-OMMT and SBS-modified asphalt for composite modification of asphalt mixtures and systematically investigates its road performance. Through the temperature sweep test, the frequency sweep test, the multiple stress creep recovery (MSCR) test, the bending beam rheometer (BBR) test, and the atomic force microscope (AFM) test, the high-temperature rheological properties, low-temperature rheological properties, high-temperature properties and aging resistance of the modified asphalt are studied. The research findings indicate that OMMT can effectively reduce the sensitivity of modified asphalt to load stress and improve its high-temperature rheological properties. SBS-modified asphalt shows increased creep stiffness and a decreased creep rate after OMMT modification, resulting in reduced flexibility and decreased low-temperature crack resistance. After short-term and long-term aging, the complex modulus aging index of OMMT/SBS composite-modified asphalt is lower than that of SBS-modified asphalt, and the phase angle aging index is higher than that of SBS-modified asphalt, demonstrating that OMMT enhances the aging resistance of SBS-modified asphalt. OMMT inhibits oxidation reactions in the asphalt matrix, reducing the formation of C=O and S=O bonds, thereby slowing down the aging process of modified asphalt and improving its aging resistance.

Study on the Storage Stability and Rheological Property of Bio-Oil/Lignin Composite-Modified Asphalt.

The objective of this study is to investigate the storage stability and rheological property of bio-oil/lignin composite-modified asphalt. The composite-modified asphalt with different proportions of bio-oil was prepared and cured at 105 °C, 135 °C, and 165 °C for 24 h and 48 h. The storage stability of the composite-modified asphalt was evaluated based on the softening point difference, the storage stability index derived from rotational viscosity, the segregation rate based on temperature sweep, and the non-recoverable creep compliance measured through the Multiple Stress Creep Recovery test. The storage stability of bio-oil/lignin composite-modified asphalt was evaluated through testing and analysis of its infrared spectroscopy and scanning electron microscopy before and after thermal storage. The research results indicate that the maximum difference in softening point is 0.9 °C, and the calculated storage stability index is generally below 0.1. The maximum value of the segregation rate is 0.43, indicating excellent storage stability of the bio-oil/lignin composite-modified asphalt. According to the results from infrared spectroscopy, no chemical reactions occurred during the storage process of the composite-modified asphalt. The scanning electron microscope confirmed that the samples became more stable after 48 h of storage.

Preparation and Properties of Waterborne Polyurethane and SBS Composite-Modified Emulsified Asphalt

To address the issue of insufficient durability of traditional modified emulsified asphalt in the application of cold mix and cold paving anti-skid wear layers, this study utilizes cationic waterborne polyurethane (PU+) for composite modification to enhance adhesion and performance across a range of temperatures. Initially, composite-modified emulsified asphalt samples were prepared with varying dosages of PU+ according to a gradient method. Routine performance tests were conducted on the evaporated residues for analysis. Advanced rheological tests, including temperature sweep (TS), frequency sweep (FS), linear amplitude sweep (LAS), and multi-stress creep recovery (MSCR) tests, were performed using a dynamic shear rheometer (DSR). Surface free energy (SFE) tests were conducted with a fully automated surface tension meter (STM). A comprehensive evaluation of the high-temperature rheological properties, fatigue properties, adhesion properties, and water damage resistance of the modified emulsified asphalt residues was carried out. Chemical changes before and after modification were characterized using Fourier transform infrared spectroscopy (FTIR), and the distribution of polymers in the evaporated residue was observed using fluorescence microscopy (FM). The results demonstrated that cationic waterborne polyurethane significantly enhanced the fatigue and adhesion properties of SBS-modified emulsified asphalt, but it also weakened the water damage resistance of asphalt. MSCR tests revealed that the addition of cationic waterborne polyurethane might reduce the elastic recovery performance of modified asphalt, thereby weakening its resistance to rutting. Among the samples, the modified asphalt with a PU+ content of 6% exhibited good high-temperature shear resistance and elastic recovery performance, demonstrating the best anti-rutting performance.

Effect of nano-modified EVA on the physical and rheological characteristics of SBR modified asphalt binder

The effects of nanoclay-modified ethylene-vinyl acetate (MEVA) on the physical and rheological properties of styrene–butadiene–rubber (SBR)-modified asphalt binder were investigated. MEVA/SBR composite-modified asphalt binders (MESBR) were prepared with 4 % SBR and varying MEVA content. The effect of MEVA on the properties of SBR-modified asphalt binder (SBRMA) was investigated through penetration, softening point, ductility, viscosity, temperature sweep, and frequency sweep tests. Furthermore, multiple stress creep recovery and bending beam rheometer tests were performed to analyse the deformation resistance and low-temperature performance of MESBR. Additionally, the storage stability of MESBR was evaluated through separation tests and fluorescence microscopy. The results indicated that MEVA addition significantly enhanced the physical and rheological properties of SBRMA both before and after ageing. Compared with SBRMA, MESBR exhibited improved deformation and ageing resistance, making it suitable for use under standard traffic loads at temperatures up to 76℃. However, MEVA exhibited a slightly negative impact on the low-temperature performance and storage stability of MESBR. With the addition of 5 % MEVA, MESBR exhibited favourable comprehensive performance and good storage stability.

Can plant-based cheese alternatives be characterized by methods for dairy cheese? Extending dairy cheese methods to characterize plant-based cheese alternatives

The techno-functional properties of dairy cheeses are often superior to their plant-based cheese alternatives. However, the constant increase in demand for plant-based cheese alternatives makes it important to achieve texture and functionality as in dairy cheeses. In this study commercial dairy cheeses and plant-based cheese alternatives were analyzed in regard to chemical composition, texture properties (unheated and heated state) and melting behavior with methods commonly applied to dairy cheeses. Especially, during an oscillatory temperature sweep, data did not show the “melting” the consumer notices while baking the product in an oven as done in the Schreiber test (2_CA, 3_CA). Therefore, a large amplitude oscillatory strain method (LAOS 60 °C) was applied and linked with the results obtained from the Schreiber test and the temperature sweep measurements. LAOS not only showed good correlation with the melting behavior observed in the Schreiber test but also allowed conclusions about the microstructure of the samples.