Surface Aggregation Research Articles

Stored platelet hemostatic phenotype and function is not altered when donors are on testosterone replacement therapy.

Critical shortages in the national blood supply have led to a re-evaluation of previously overlooked donor sources for blood products. As a part of that effort, red blood cells collected from therapeutic phlebotomy of donors on testosterone replacement therapy (TRT) have been conditionally approved for transfusion. However, platelets from TRT donors are not currently approved for use due to limited data on effects of supraphysiologic testosterone on recipient safety and platelet function. The objective of this study was to provide a comprehensive profile of phenotype and function in platelets from TRT and control donors. Platelets in plasma were collected from TRT and control donors (N = 10 per group; age- and sex-matched) and stored at room temperature for 7 days. On storage Day 1 (D1) and Day 7 (D7), platelet products were analyzed for platelet count, metabolic parameters (i.e., glucose, lactate, mitochondrial function), surface receptor expression, aggregation, thrombin generation, and thrombus formation under physiological flow conditions. TRT donor platelets were not significantly different than control donor platelets in terms of count, surface phenotype, metabolic function, ability to aggregate, thrombin generation, or ability to form occlusive thrombus under arterial flow regimes. Both groups were similar to each other by D7, but had significantly lost hemostatic function compared to D1. Platelets derived from donors undergoing TRT have similar phenotypic and functional profiles compared to those derived from control donors. This suggests that therapeutic phlebotomy of TRT donors may provide a useful source for platelet products.

Study on the influence of tire polishing on surface texture durability and skid resistance deterioration of asphalt pavement

As an inherent attribute of asphalt pavement, texture durability is the essential reason for the change in skid resistance. However, different scale texture deterioration behavior remains unclear by tire wearing at present. To explore the influence of the durability of multi-scaled textures on skid resistance, nine pavement specimens were tested using the Harbin polishing and dynamic friction integrated experimental machine (HPFM). The pavement anti-skid texture tester (PATT-II) was used for high-precision texture scanning and reconstruction. The results show that the texture richness and skid resistance of the three types of pavements in 300 min polishing are ranked as Open-graded Friction Coarse (OGFC) > Stone Mastic Asphalt (SMA) > Asphalt Concrete (AC), while SMA presents the best durability, determined by the material skeleton structure of asphalt mixture. The macro-texture deterioration occurs slightly at first and then tends to stabilize in 300 min polishing. The micro-texture deterioration behavior is the same as the μHPFM, increasing rapidly at the beginning, then slowly decreasing, and finally remaining constant. This deterioration is caused by the asphalt damage and continuously wearing aggregate surface. The 2D-PSD deterioration behavior is more significant with a smaller texture scale in 300min polishing, and the most considerable contribution wavelength in the microscopic scale range is 0.15 mm–0.3 mm, which is determined by the adhesion characteristics and molecular mechanism between a mineral mixture and asphalt material. The influence of pavement texture on the dynamic friction coefficient is significantly different under different water film thicknesses, the micro-texture and macro-texture play the main roles in boundary and mixed lubrication, respectively.

Microscopic behavior of heteroatom asphaltene in the multi-media model: The effect on heavy oil properties

The high viscosity and surface adsorption of heavy oil pose significant challenges for its exploration. Asphaltenes, the most polar and heaviest components of crude oil, play a crucial role in these properties. Heteroatom asphaltenes (A-X, S-Y) exhibit stronger interaction energy compared to non-heteroatom asphaltenes A-C. The self-assembly of A-X/S-Y forms ordered "reinforcement-cement" aggregates, whereas A-C aggregates are more chaotic. The presence of heteroatoms, particularly the sulfur atom in the side chains, may significantly influences asphaltene aggregation structures. The diffusion coefficient of heteroatom asphaltene in oil droplet is smaller than that of A-C, and these heteroatom compound can bind other oil components, reducing the overall fluidity. Notably, the adsorption energy of asphaltenes on solid surfaces exceeds their interaction energy. Surface aggregation of A-X/S-Y is more dispersed compared to A-C adsorption system. Additionally, the existence of heteroatom asphaltenes can shorten the distance between oil droplets and the solid surface by 16.20 Å compared with non-heteroatom system. These phenomena, caused by A-X/S-Y, further complicate the detachment of crude oil components from surfaces. This study aims to share some new insights into the micro-mechanisms of heteroatom asphaltenes self-assembly and the behavior in the oil-sludge process, which may contribute to the theoretical foundation for the targeted and efficient exploitation of heavy oil.

Polydimethylsiloxane enabled triple-action water-resistant coating with desirable relaxation rate in clear aligner

Clear aligners undergo rapid stress relaxation in warm, moist oral environments, compromising therapeutic effectiveness and longevity of treatment. To develop an innovative multilayer composite material with improved stability and reduced stress release, we have engineered an innovative coating characterized by the surface aggregation of polydimethylsiloxane (PDMS), which imparts a pronounced hydrophobic effect. In addition, the chemically and physically cross-linked structure of the coating reduces the free volume created by molecular chain rearrangement owing to the presence of water molecules, thereby minimizing water penetration into the coating. Concurrently, the coating’s internal structure is enriched with numerous polar functional groups to capture water molecules that penetrate into the inside of the coating. Through combination of these mechanisms, water molecules are effectively sequestered, thereby impeding their penetration into the polyethylene terephthalate glycol (PETG) substrate. The impact of the polydimethylsiloxane content on the triple-action water-resistance mechanisms was thoroughly examined using attenuated total reflection (ATR)-Fourier transform infrared (FTIR), water absorption rate, water swelling rate, and X-ray photoelectron spectroscopy. The low surface energy cross-linked polyurethane coating is applied to the polyethylene terephthalate glycol (PETG) substrate to create a novel composite material with specific mechanical properties and reduced stress relaxation. The composite material remains stable in simulated oral environment with linear swelling rate of 0.58 % upon water absorption. Additionally, the stress release rate of the composite material within 336 h is notably lower (23.64 %) than that of PETG (62.29 %).

Calcium nitrate effectively mitigates alkali–silica reaction by surface passivation of reactive aggregates

AbstractCalcium nitrate (CN: Ca(NO3)2) has been shown to mitigate alkali–silica reaction (ASR) in concrete. Such ASR mitigation has been suggested to be on account of precipitate (i.e., barrier or passivation layer) formation‐induced dissolution inhibition of reactive/dissolving aggregate surfaces. Herein, we examine the ability of CN to mitigate ASR across two cements (Type I/II and Portland Limestone Cement), for aggregates of varying reactivity, and across different types and dosages of SCMs (supplementary cementitious materials, i.e., amorphous steel slag and Class C and Class F fly ashes). Based on expansion measurements carried out as per ASTM C1260/C1567, it is observed that CN, as a function of dosage, substantively mitigates ASR in mortar formulations across aggregate types. Careful microstructural examinations, dissolution studies, and thermodynamic calculations indicate that CN induces the formation of C–S–H, portlandite (Ca(OH)2), and calcite (CaCO3) precipitate mixtures, which form on aggregate surfaces at the expense of typical ASR gels. Such precipitates create a dissolution barrier and inhibit ASR in both SCM‐free and SCM‐containing formulations. The outcomes indicate that CN is an efficient and cost‐effective ASR mitigation additive (∼$250–$600 per tonne), particularly in a time of dwindling fly ash supplies and unaffordable lithium prices (>∼$12 000 per tonne).

Enhancement mechanism of microbial mineralization modified coal gangue aggregate properties

Preparing concrete with coal gangue as the aggregate has significant environmental and economic advantages. Nevertheless, the fundamental characteristics of the manufactured concrete are significantly impacted by the high water absorption and low strength of coal gangue aggregate. The present study employs the microbial-induced carbonate precipitation (MICP) technique to efficiently enhance the characteristics of coal gangue aggregate (CGA). Starting from the circumstances of microbial mineralization, the effects of pH, temperature, and time on the capacity of bacteria for mineralization were taken into consideration. Following solution immersion treatment with varying concentrations of urea, calcium ions, and bacterial solution, the patterns of water absorption, crushing index, apparent density, and ultrasonic pulse resistance of CGA were examined. The precipitates produced by microbial mineralization, the micro-morphology, and the pore structure of the aggregate surface were all characterized, and the mechanism of the modification of CGA by MICP was revealed through the use of scanning electron microscopy (SEM), X-ray diffractometer (XRD), and nuclear magnetic resonance (NMR) techniques. Investigations were also conducted on the mechanical characteristics of modified coal gangue aggregate concrete. The results showed that the water absorption and crushing index of the CGA with optimal modification effect (M-CGA) decreased by 18.5 % and 24.1 %, respectively, which was attributed to the fact that the calcium carbonate formed in the cracks and pores of the CGA filled the aggregates and prevented the penetration of water. The 28-day compressive strength, split tensile strength, and flexural strength of modified coal gangue aggregate concrete prepared from M-CGA were increased by 8.13 %, 13.88 %, and 8.53 %, respectively. MICP is an effective method to improve the properties of CGA, which is conducive to the waste recycling of coal gangue.

Enhancing concrete durability and strength: An innovative approach integrating abrasion and cement slurry treatment for recycled coarse aggregates

AbstractThis study introduces a novel approach to enhance the durability and strength of concrete by integrating abrasion and cement slurry treatments on surface‐treated recycled coarse aggregates (STRCA). Initial abrasion treatment removes aged mortar from the recycled coarse aggregate (RCA) surface, while subsequent cement slurry modification provides a fresh surface, reinforcing the bond with the concrete matrix. Through detailed material analyses including x‐ray diffraction, scanning electron microscopy, and energy‐dispersive x‐ray, microstructural changes are evaluated alongside compressive strength, drying shrinkage, electrical resistivity, and chloride ion penetration of STRCA‐based concrete. Results indicate significant improvements in mechanical properties and durability as the treatments eliminate mortar and enhance the interfacial connection with cement paste. Notably, a substantial 29.37% strength enhancement is observed at 25% replacement (STRCA 25), demonstrating treatment efficacy. While a reduction of 11.58% occurs at 100% replacement (STRCA 100), up to 75% replacement shows minimal strength loss, with optimal enhancements at 50% replacement. Additionally, STRCA concrete exhibits lower drying shrinkage (11%–20% reduction) and increased electrical resistivity (28%–36% rise), indicating improved durability at 100% replacement. Enhanced resistance to chloride ion penetration is also evident, with a 22%–28% increase at 100% replacement compared to conventional RCA. Overall, this study highlights the effectiveness of dual treatments for enhancing concrete properties using STRCA.

Differences in structure, physicochemical properties, and in vitro digestibility of three types of starch complexed with tannic acid

The structure of starch often influences its interaction mode and affinity with polyphenols, subsequently impacting the functional properties of starch-polyphenol complexes. This study delved into the multiscale structure, physicochemical properties, and digestive performance of complexes formed by tannic acid (TA) with starches of different polymorphisms (corn starch (CS), potato starch (PS), and pea starch (ES)). The results revealed that TA induced notable changes in the surface morphology and aggregation behavior of starch pastes, with the most pronounced effects observed in ES. Elevated gelatinization enthalpy change and decreased thermal stability were observed in ES-TA complexes, contrary to complexes formed with CS and PS. TA enhanced the crystallinity of three pre-gelatinized starches, facilitating the formation of long-range ordered structures but disrupting short-range ordered structures, with effects more pronounced and TA-concentration-dependent in CS and ES rather than PS. The viscoelasticity of PS gel was strengthened, while that of CS and ES gels was reduced by TA. Digestive outcomes demonstrated that TA increased the resistance to digestion in all three starches, with CS exhibiting the most significant effect, followed by ES and PS. This might be linked to the binding modes of TA with different crystalline starches. The observed variations in regulatory effects on structure and function of starches from different sources combined with TA enhanced our understanding of TA-starch interactions, providing insights into the interaction between polyphenols and starch of different crystalline types.

Soil pores in preferential flow terminology and permeability equations

AbstractLinkages between the micro‐scale of soil water and landscape scale of hydrological data could be improved with the analysis of soil factors in preferential flow rates. This rearrangement of the terminology on soil pore size from published literature focused on the relationship between aggregate and pore size. In the range of pore size relevant to water flow (>0.005 mm), a 2:1 ratio of aggregate to pore diameter approximated the mean of proposed pore size categories. Major functional change points in soil pore size were identified where water becomes mobile in soil (0.005 mm), where preferential flow among aggregate surfaces begins (0.3 mm), and where water flows without soil interaction (bypass flow ∼1.0 mm). A number of published equations supported the application of soil pore size in permeability estimation for modeling hydraulic conductivity. Common understanding of soil pore terminology would support water flow estimation from soil to landscape scales.

Primary Sjögren syndrome specific B cells induced aberrant surface aggregation of B cell receptors (BCRs) and signalling

Primary Sjögren’s syndrome (pSS) is a systematic autoimmune manifestation of the exocrine glands caused by impaired lymphocytic infiltration, leading to dry eyes and xerostomia. The pathologic hallmark of this disease is the dysfunction of the exocrine glands, which results in dry eyes and mouth. Clinical observations suggest that B cells contribute to the pathogenesis of pSS through the enhanced secretion of autoantibodies, hypergammaglobulinemia, reduced free light chains, and a higher B cell lymphoma. Despite increased evidence of B cell hyperactivation and dysregulated B cell interactions in pSS, detailed speculations into the mechanism by which pSS-specific B cells exhibited abnormal BCR signaling repertoires and the magnitude of downstream signaling responses remain limited. Upon encountering antigens, B lymphocytes produce neutralizing antibodies by phosphorylating immune receptor tyrosine activation motifs (ITAMs). Despite these advancements, we still do not understand how pSS-specific B cells influence the surface clustering of BCRs and subsequent downstream immune responses. This paper hypothesizes that pSS-specific B cells encountering surrogate antigens will undergo a coordinated series of events that initiate B cell activation and spatiotemporal dynamics of BCRs. Additionally, we assume that pSS individuals have aberrant BCR repertoire and clonal expansion. In the future, these studies can provide detailed therapeutic entanglements for B cell-linked autoimmune and other hypersensitive disorders.

Interfacial adhesion between recycled asphalt binder and aggregates considering aggregate surface anisotropy: A molecular dynamics simulation

In this study, the interfacial adhesion properties between reclaimed asphalt binder and aggregates were investigated using the molecular dynamics (MD) simulation method. Surface free energy theory (SFE) was applied to analyze the changes in adhesion properties before and after asphalt binder reclamation. The asphalt binder model was constructed from the four components of asphalt binder and validation of the model was carried out. The five common crystalline surfaces of two types of aggregates were sliced. The asphalt binder-aggregate interface was modelled to investigate the effect of the anisotropic surface of the aggregates on the adhesion of the asphalt binder. The adhesion properties of the recycled asphalt binder-aggregate interface were characterized from micro and multiscale simulations using the work of adhesion and relative concentration. Results showed that the rejuvenators enhanced the adhesive properties of the asphalt binder by rebalancing the components and adding the light components lost from aging. Surface anisotropy had significant effect on the bonding at the asphalt binder-aggregate interface because α-SiO2 bonded to acid surfaces less strongly than CaCO3 linked to alkali surfaces. Van der Waals forces dominated the adhesion energy in the α-SiO2-asphalt binder interfacial model system. In the CaCO3-asphalt-binder interface model system, the combined effect of van der Waals forces and the CaCO3 surface void reduced the adhesion energy of the aggregate surface to the asphalt binder.

Assessment of the migration characteristics and source-oriented health risks of heavy metals in the soil and groundwater of a legacy contaminated by the chlor-alkali industry in central China.

The chlor-alkali industry (CAI) is crucial for global chemical production; however, its operation has led to widespread heavy metal (HM) contamination at numerous sites, which has not been thoroughly investigated. This study analysed 122 soil and groundwater samples from a typical CAI site in Kaifeng, China. Our aim was to assess the ecological and health risks, identify the sources, and examine the migration characteristics of HMs at this site using Monte Carlo simulation, absolute principal component score-multiple linear regression (APCS-MLR), and the potential environmental risk index (Ei). Our findings revealed that the exceedance rates for Cd, Pb, Hg, and Ni were 71.96%, 45.79%, 49.59%, and 65.42%, respectively. Mercury (Hg) displayed the greatest coefficient of variation across all the soil layers, indicating a significant anthropogenic influence. Cd and Hg were identified as having high and extremely high potential environmental risk levels, respectively. The spatial distributions of the improved Nemerow index (INI), total ecological risk (Ri), and HM content varied considerably, with the most contaminated areas typically associated with the storage of raw and auxiliary materials. Surface aggregation and significant vertical transport were noted for HMs; As and Ni showed substantial accumulation in subsoil layers, severely contaminating the groundwater. Self-organizing maps categorized the samples into two different groups, showing strong positive correlations between Cd, Pb, and Hg. The APCS-MLR model suggested that industrial emissions were the main contributors, accounting for 60.3% of the total HM input. Elevated hazard quotient values for Hg posed significant noncarcinogenic risks, whereas acceptable levels of carcinogenic risk were observed for both adults (96.60%) and children (97.83%). This study significantly enhances historical CAI pollution data and offers valuable insights into ongoing environmental and health challenges.

Ultrasonic wave characteristics in multiscale cementitious materials at different stages of hydration

Monitoring the microstructural change in cementitious materials during hydration is an essential but challenging task. Therefore, a non-invasive and sophisticated technique is warranted to understand the microscopic behaviour of the multiphase cementitious materials (where the length scale of the constituents varies from centimeters to micrometers) in different stages of hydration. Due to exothermic hydration reactions, different hydration products start to evolve with individual mechanical properties. In concrete, an interface transition zone (ITZ) appears between the aggregate surface and paste matrix, which influences the overall properties of concrete material. In the present research, 1) several wave characteristics, such as wave velocity, energy distribution, and signal phase are found out using Ultrasonic Pulse Velocity (UPV), Wavelet Packet Energy (WPE) and Hilbert Transform (HT) methods, to monitor the hydration mechanism (1d-28d) in cement-based materials with two levels of heterogeneities (cement paste and concrete, representing microscale and mesoscale, respectively). Also, the unique nonlinear behaviour is studied in the frequency domain using the promising Sideband Energy Ratio (SER) and Sideband Peak Count Index (SPC-I) methods. 2) Numerical simulations are carried out to understand the wave interaction in the developing microstructure. A discretized microstructure of cement shows microscopic details of each phase at any instant of hydration (e.g., formation stage and after complete maturity level). The experimental and numerical investigations on the characteristics of the nonlinear ultrasonic wave propagation show the impact of microstructural development of multi-scale cementitious materials during hydration.

Mechanisms of interface electrostatic potential induced asphalt-aggregate adhesion

The electrostatic potential at the interface of the asphalt molecular and aggregate oxides is the primary factor generating the adhesion between the asphalt-aggregate contact surfaces. However, the route of electrostatic potential affecting the asphalt-aggregate adhesion is yet to be determined at the molecular level. This study proposed that the electron accumulation at the interface of the asphalt molecular and aggregate oxides generates a significant electrostatic potential hence to induce the adhesion between the asphalt and aggregate in asphalt pavement. A microscopic molecular dynamics (MD) simulation incorporated with macroscopic adhesion work experiments is conducted to analyze the interface adhesive performance between the asphalt and aggregate. The adhesion work experiment demonstrated the effect of aggregate surface oxides on asphalt adhesion at the macro level and further verified the simulation results. The result demonstrated that a notable electron accumulation can be observed by MD at the interface of asphalt molecular and multiple oxides which generates the electrostatic potential. The strong electrostatic attractions and hydrogen bonds between alkaline oxides (MgO, CaO, CaCO3) and asphalt molecules enhance the relative concentration distribution, diffusion coefficient, and adhesion of asphalt on the aggregate surface. The significant electrostatic potential difference at the interface of the asphalt molecular and the oxide enables a strong adhesion between them due to the near-surface failure potential. Besides, the negative charge accumulation on both the benzene ring structure and oxygen atoms in the asphalt molecules results in poor adhesion at the interface of asphalt molecules and multiple oxides. It was found that a high correlation exists between the MD prediction and experimental testing results. Thus, this research provides a valuable tool for guiding the pairing and selection of asphalt with various minerals for pavement design, construction, and maintenance agencies.

Research on the adhesion mechanism and compatibility of acrylate composite polyurethane binder − aggregate based on surface free energy theory

The raw materials selection and design of waterproof polymer concrete for steel bridge deck paving lack clarity regarding the adhesion mechanism and optimal compatibility between acrylate composite polyurethane binder (APUB) and various aggregates. This study systematically investigates these issues based on surface free energy (SFE) theory. Initially, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques are utilized to characterize chemical structure of APUB. Subsequently, obtaining the SFE parameters of APUB and aggregates through contact angle tests, and establishing the evaluation indices compatibility ratios ERs (ER1 and ER2) for the most compatible APUB-aggregate pairs. Finally, the correlation between ERs and the water stability of the APUB-aggregate pair is verified through shear tests conducted on sandwich specimens immersed in water. The findings reveal that APUB exhibits both acidic and non-polar surface properties. The SFE values of all aggregates surpasses that of APUB, indicating APUB's ability to wet the surfaces of all aggregates. Under dry conditions, non-polar basalt and limestone aggregates exhibit strong adhesion to APUB. This is primarily due to the combined effects of acid-base chemical reactions and the principle of compatibility, with the former predominating. Under wet conditions, APUB on non-polar basalt and limestone surfaces exhibits reduced susceptibility to displacement and detachment by water. The closer the polarity component of polar aggregates is to that of water, the easier water can displace APUB from the polar aggregate surfaces. Correlation analysis between the maximum shear force of the immersed specimens and the ER2 indicates that the APUB-basalt pair has the best compatibility. The cohesive work of APUB is crucial in establishing compatibility indicators for evaluating APUB-aggregate pairs. This study provides a theoretical basis for the raw material selection and design of polymer concrete for steel bridge deck paving.

An investigation toward adhesion characteristics of emulsified asphalt residue–aggregate interface through MD simulation

The bonding ability of emulsified asphalt residue-aggregate interface is crucial for improving the pavement performance of emulsified asphalt mixtures. The aim of the study was to explore the adhesion mechanism and characteristics of emulsified asphalt residue-aggregate interface under the different emulsifier contents using molecular dynamics (MD) simulation. Firstly, the emulsified asphalt residue-aggregate interface model was established, and its validity was validated through the related thermodynamic properties. Secondly, the performance-related parameters were employed to discuss the molecular arrangement features of emulsified asphalt residue components on the aggregate surface, and investigate the interfacial adhesion mechanism. Thirdly, the adhesion strength of emulsified asphalt residue-aggregate interface was calculated and evaluated by the adhesion energy. Lastly, the influence of temperature and moisture on the interfacial adhesion strength was further examined through the molecular orientation theory and the electrostatic interaction theory. The results indicate that the addition of emulsifiers could affect the aggregation behaviors and distribution characteristics of asphalt components as observed from performance-related parameters. When compared to relatively high emulsifier content (4–6 %), the molecular arrangement of emulsified asphalt residue components with relatively low emulsifier content (1–3 %) is more similar to that of the base asphalt and exhibits greater interfacial adhesion strength with aggregates. The polar components and emulsifiers in emulsified asphalt residue with relatively low emulsifier content are minor affected by the increase of temperature, which further proving that interfacial adhesion strength is higher at this condition. Meanwhile, emulsified asphalt residue with relatively low emulsifier content is confirmed to have better moisture damage resistance due to the existence of the certain number of Silica-Water(S-W) and Asphalt-Water(A-W) hydrogen bonds near interface. Moisture exhibits more significant influence on the interfacial adhesion strength between emulsified asphalt residue and aggregates according to the results of the average adhesion energy. It is advisable to apply emulsified asphalt with moderate emulsifier content during the actual production process considering the influence of moisture and temperature on the pavement performance of emulsified asphalt mixtures.

Study on cohesion and adhesion behaviors of the zeolite foamed asphalt-warm mix mixture based on molecular dynamics simulation

Zeolite foamed asphalt - warm mix mixture (ZFA-WMM) has been applied in large quantities in asphalt pavement, however, a lower construction temperature, residual zeolite water and zeolite minerals have different effects on the cohesion and adhesion properties of zeolite foamed asphalt (ZFA), which indirectly affects the water stability of its mixture. This study analyzed the interface behavior in ZFA-WMM using molecular dynamics simulation. First, the molecular model of ZFA was constructed, and its thermodynamic properties were calculated and compared with experimental values and related simulated values to validated the reasonable of model. Then, the interface models of ZFA-aggregate (quartz and calcite) and ZFA-ZFA were established, simulating the effects of the zeolite mineral dosage, temperature, and interface moisture (residual zeolite water) content on the cohesion and adhesion of ZFA. Furthermore, the occurrence mode of cohesion or adhesion failures in ZFA-WMM were predicted by comparing the ZFA-aggregate adhesion work with ZFA cohesion work. The simulation results indicated that as the zeolite mineral dosage increased, the ZFA cohesion and ZFA-calcite adhesion increased, while ZFA-quartz adhesion first grew and then dropped, reaching its maximum at 9.4 % zeolite mineral dosage. Under the pavement operating temperature range (-15°C∼65°C), higher pavement temperatures are beneficial to ZFA-aggregate adhesion; the cohesion of ZFA first increases and then decrease as temperature rises, reaching its maximum at 25℃. The larger the interface moisture content, the higher the possibility of water separating ZFA from the aggregate surface and the water sensitivity of ZFA-WMM. The ZFA-WMM is prone to adhesion failure, especially at higher zeolite dosages.

Adhesion pilus retraction powers twitching motility in the thermoacidophilic crenarchaeon Sulfolobus acidocaldarius

Type IV pili are filamentous appendages found in most bacteria and archaea, where they can support functions such as surface adhesion, DNA uptake, aggregation, and motility. In most bacteria, PilT-family ATPases disassemble adhesion pili, causing them to rapidly retract and produce twitching motility, important for surface colonization. As archaea do not possess PilT homologs, it was thought that archaeal pili cannot retract and that archaea do not exhibit twitching motility. Here, we use live-cell imaging, automated cell tracking, fluorescence imaging, and genetic manipulation to show that the hyperthermophilic archaeon Sulfolobus acidocaldarius exhibits twitching motility, driven by retractable adhesion (Aap) pili, under physiologically relevant conditions (75 °C, pH 2). Aap pili are thus capable of retraction in the absence of a PilT homolog, suggesting that the ancestral type IV pili in the last universal common ancestor (LUCA) were capable of retraction.

Variation of SARA fractions of crumb rubber modified asphalt binder-aggregate interface system and its correlation with adhesion properties

The incorporation of rubber powder leads to a high degree of complexity in the CRMA binder-aggregate interfacial properties, which directly affects the interfacial adhesion performance. The objective of this study is to investigate the variation of SARA fractions of CRMA binder during the adhesion process and to explore the intrinsic relationship between the components and the adhesion properties. To this end, the staged extraction tests were performed to extract CRMA binder layers on the aggregate surface. After each extraction, the binder layer was evaluated in terms of its SARA fraction contents and molecular weight distribution. Additionally, the pull-off tensile strength (POTS) was used to assess the adhesion of the binder-aggregate interface through the binder bond strength (BBS) test. Finally, the correlation between the SARA fractions of CRMA binder and interface adhesion of CRMA binder-aggregate system was analyzed. The results showed that the CR tends to absorb the lighter components of base asphalt, the variations in SARA fractions and molecular weight distribution during the aggregate adhesion to CRMA binders occurred mainly in the third and fourth elution layers. Pen 70 CRMA binder and limestone show the best adhesion properties among all the binder and aggregate types. The increase in CR size and the decrease in CR dosage are favorable for the adhesion of CRMA binders to aggregates. Furthermore, asphaltenes and resins are positively correlated with adhesion, while aromatics and saturants are negatively correlated with adhesion. The correlation between SARA content and adhesion varied depending on the aggregate type.

Continuous Biogas Slurry Substitution of Chemical Fertilizer with Wheat/Maize Straw Return Alters Surface and Subsoil Physicochemical and Aggregate Properties Differently

Continuous Biogas Slurry Substitution of Chemical Fertilizer with Wheat/Maize Straw Return Alters Surface and Subsoil Physicochemical and Aggregate Properties Differently