Rejuvenation Effect of Aged SBS-Modified Asphalt Utilizing Molecule Analysis

The Performance of Styrene-Butadiene-Styrene Modified Asphalt (SBSMA) is Significantly Impacted by its Aging and Regeneration. in This Research, the Molecular Dynamics Simulation Was Utilized to Investigate the Rejuvenation Effect of Active Reagents on Aged SBS Modified Asphalt through the Following Tasks: 1) Verifying the Accuracy of the Asphalt Model by Density and Solubility Parameters; 2) Assessing the Changes in the Rejuvenated Asphalt Model\u27s Energetic Parameters and Volume Parameters, 3) Studying the Interaction Energy between SBS Molecules and Asphalt Molecule Models, and 4) Evaluating the Relative Concentration, Interfacial Interaction Energy, and Diffusion Effect of the Asphalt-Asphalt Models. the Results Indicated that the Restored Broken SBS Molecule Substantially Impacted the Functionality of the Rejuvenated Asphalt Binder. for Methylene-Bis(4-Cyclohexylisocyanate) (HMDI) and 1,6-Hexanediol Diglycidyl Ether (HDE) Rejuvenated Asphalts, the Non-Bond Energy Decreased Gradually with the Repair of Broken SBS Molecular Structures. the Free Volume Fraction of Rejuvenated Binders Was Lower Than that of SBSMA, indicating that the Compactness and Packing Degree of the Rejuvenated Asphalt Were Increased. the Interaction Energy between SBS and Asphalt Molecules in Rejuvenated Asphalt Increased Because of the Enhanced Van Der Waals Interaction between the Reconstructed SBS Molecule and Rejuvenated Binders. the Free HDE Molecular Chain Reduced the Interaction Energy between SBS and Asphalt Molecules. for the Asphalt-Asphalt Models, the Diffusion Coefficient of the SBSMA-Rejuvenated Asphalt Model Was Lower Than that of the SBSMA-SBSMA Model. the HDE Rejuvenated Asphalt Showed Better Diffusion Behavior Than SBSMA, and SBS Molecules Repaired by HDE Had Excellent Fluidity. the Interfacial Interaction Energy of the SBSMA-Rejuvenated Asphalt Model Was Higher Than that of the SBSMA-SBSMA Model. with the Repair of the Broken SBS Molecular Chain, the Interfacial Interaction Energy between HMDI Rejuvenated Asphalt and SBSMA Increased Gradually. in Contrast, the Interfacial Interaction Energy between HDE Rejuvenated Asphalt and SBSMA Decreased Gradually. the Fully Restored SBS Molecular Structure Had Stable Thermodynamic Properties and Could Accelerate the Diffusion Effect of Rejuvenated Asphalt

Evolution Of SBS-Modified Asphalt Performance Under Aging And Rejuvenation Cycle Conditions

Improving the poor long-term service performance of rejuvenated SBS-modified asphalt (REF-LT) is highly challenging. In this study, a blend of aged and virgin binders was used to rejuvenate REF-LT and the evolution of the asphalt performance was observed during regeneration and reaging processes. An SBS-modified asphalt (SBM) and base asphalt (BA) were mixed with REF-LT in specified ratios to prepare SBM- and BA-rejuvenated asphalts. The rejuvenated asphalts were subjected to short- and long-term aging. The high/low-temperature rheological properties, fatigue resistance, rejuvenation mechanism, and changes in the functional groups of the rejuvenated and reaged asphalts were characterized using a dynamic shear rheometer (DSR) and Fourier transform infrared spectroscopy (FTIR). The antiaging performance of the rejuvenated asphalt was evaluated. Temperature sweep results showed that both SBM and BA mitigated hardening in REF-LT. BA had a stronger softening effect on REF-LT than SBM. However, the BA-rejuvenated asphalt was more temperature sensitive than the SBM-rejuvenated asphalt. The BA-rejuvenated asphalt had poor resistance to reaging, whereas the SBM-rejuvenated asphalt demonstrated outstanding resistance to long-term aging. The Glover–Rowe (G-R) parameters indicated that after short-term aging, the rejuvenated asphalts remained in the no cracking zone, demonstrating outstanding resistance to thermal cracking. A total of 20 h of long-term aging of the rejuvenated asphalts decreased the crossover frequency and increased the rheological index, suggesting an increased risk of cracking. Relaxation tests showed that the BA-rejuvenated asphalt had a lower peak stress than that of the SBM-rejuvenated asphalt; however, the durability of the BA-rejuvenated asphalt was compromised because of the peak stress rapidly increased after reaging. Although the BA-rejuvenated asphalt exhibited good short-term crack resistance, its poor durability resulted in inferior thermal crack resistance to that of the SBM-rejuvenated asphalt after long-term aging. Linear amplitude sweep (LAS) tests indicated that the SBM-rejuvenated asphalt had a lower damage rate than the BA-rejuvenated asphalt, suggesting that the polymer network structure provided excellent damage resistance. The fatigue life of the BA-rejuvenated asphalt decreased considerably after reaging, indicating insufficient long-term fatigue resistance. The FTIR results indicated that the REF-LT rejuvenation process involved physical blending and the SBM-rejuvenated asphalt exhibited superior antiaging capability to the BA-rejuvenated asphalt. Increasing the BA content did not improve the long-term antiaging performance of the BA-rejuvenated asphalt. The higher antiaging performance of the SBM-rejuvenated asphalt resulted from the polymer network structure

Thermodynamic Study on the Direct Reduction of Specularite by Lignite and the Coupling Process for the Preparation of Cementitious Material

To realize the efficient and comprehensive utilization of specularite resources, combined with the cement clinker production technology of rotary kilns, the coupling process of the direct reduction of specularite by lignite and the preparation of cementitious material was proposed, with the additional aim of achieving the reduction of iron oxide and transforming the gangue component into cementitious material. Thermodynamic software was used to calculate the product composition when the reaction reached equilibrium under the set conditions. By analyzing the influence of the ratio of C/O, basicity, temperature, and other parameters on the reduction of iron oxide and cementitious material generation, the feasibility of the process was judged and experimentally verified. The results showed that the coupling process of the direct reduction of specularite and the preparation of cementitious material was thermodynamically feasible when using highly volatile lignite with added calcium oxide. The optimal C/O ratio of the reducing agent was 1.2 for the complete reduction of iron oxide (Fe2O3, Fe3O4, FeO) without the gangue fraction; reduced iron could stably coexist with the cementitious material components, but the unreduced FeO would result in a substantial reduction in tricalcium silicate generation. Using lignite as a reducing agent, the hydrogen-rich volatiles in coal created a good reducing atmosphere, strengthened the reduction process of iron oxide, and provided favorable conditions for the generation of cementitious material. A two-stage heating system must be adopted to realize the reduction of iron oxide and the generation of cementitious material. The process parameters conducive to the reduction of specularite and cementitious materials were determined, the basicity range of the system was regulated to 2.4–3.3, the reasonable reduction temperature was close to and not higher than 1137 °C, and the optimal temperature of cementitious material generation was 1450 °C

Thermodynamic Study on the Direct Reduction of Specularite by Lignite and the Coupling Process for the Preparation of Cementitious Material

To realize the efficient and comprehensive utilization of specularite resources, combined with the cement clinker production technology of rotary kilns, the coupling process of the direct reduction of specularite by lignite and the preparation of cementitious material was proposed, with the additional aim of achieving the reduction of iron oxide and transforming the gangue component into cementitious material. Thermodynamic software was used to calculate the product composition when the reaction reached equilibrium under the set conditions. By analyzing the influence of the ratio of C/O, basicity, temperature, and other parameters on the reduction of iron oxide and cementitious material generation, the feasibility of the process was judged and experimentally verified. The results showed that the coupling process of the direct reduction of specularite and the preparation of cementitious material was thermodynamically feasible when using highly volatile lignite with added calcium oxide. The optimal C/O ratio of the reducing agent was 1.2 for the complete reduction of iron oxide (Fe2O3, Fe3O4, FeO) without the gangue fraction; reduced iron could stably coexist with the cementitious material components, but the unreduced FeO would result in a substantial reduction in tricalcium silicate generation. Using lignite as a reducing agent, the hydrogen-rich volatiles in coal created a good reducing atmosphere, strengthened the reduction process of iron oxide, and provided favorable conditions for the generation of cementitious material. A two-stage heating system must be adopted to realize the reduction of iron oxide and the generation of cementitious material. The process parameters conducive to the reduction of specularite and cementitious materials were determined, the basicity range of the system was regulated to 2.4–3.3, the reasonable reduction temperature was close to and not higher than 1137 °C, and the optimal temperature of cementitious material generation was 1450 °C

SDC-DeepLabv3+: Lightweight and Precise Localization Algorithm for Safflower-Harvesting Robots

Harvesting robots had difficulty extracting filament phenotypes for small, numerous filaments, heavy cross-obscuration, and similar phenotypic characteristics with organs. Robots experience difficulty in localizing under near-colored backgrounds and fuzzy contour features. It cannot accurately harvest filaments for robots. Therefore, a method for detecting and locating filament picking points based on an improved DeepLabv3+ algorithm is proposed in this study. A lightweight network structure, ShuffletNetV2, was used to replace the backbone network Xception of the traditional DeepLabv3+. Convolutional branches for 3 different sampling rates were added to extract information on the safflower features under the receptive field. Convolutional block attention was incorporated into feature extraction at the coding and decoding layers to solve the interference problem of the near-color background in the feature-fusion process. Then, using the region of interest of the safflower branch obtained by the improved DeepLabv3+, an algorithm for filament picking-point localization was designed based on barycenter projection. The tests demonstrated that this method was capable of accurately localizing the filament. The mean pixel accuracy and mean intersection over union of the improved DeepLabv3+ were 95.84% and 96.87%, respectively. The detection rate and weights file size required were superior to those of other algorithms. In the localization test, the depth-measurement distance between the depth camera and target safflower filament was 450 to 510 mm, which minimized the visual-localization error. The average localization and picking success rates were 92.50% and 90.83%, respectively. The results show that the proposed localization method offers a viable approach for accurate harvesting localization

Multiscale Investigation of Waste Soybean Oil Rejuvenated Asphalt Binder Utilising Experimental Methodologies and Molecular Dynamics Simulations

To Demonstrate the Rejuvenation Effect of Waste Soybean Oil (WSO) on Aged Asphalt Binder (AB) and Realise the Efficient Combination of Laboratory Evaluation and Numerical Simulation. the Rheological Properties and Molecular Dynamics Simulation of WSO Rejuvenated Binders Were Investigated. the Results Demonstrated that the WSO Provided Sufficient Light Components in the AB and Reduced the Stiffness. the WSO Rejuvenated Binders Were Transformed into a Sol–gel Structure, This Resulted in Excellent Rheological Properties. the WSO Improved the Anti-Fatigue Performance of Rejuvenated Binders. the WSO Provided Sufficient Aromatics and a Small Amount of Saturates for the AB. the Blending Mechanism of WSO and AB Was Physical Blending. the Atomic Force Microscopy Micromorphology Images Showed that the Bee-Like Structure of WSO Rejuvenated Binders Was Reduced in Quantity Compared with that of AB. the Dosages of 3–6 Wt% of AB Content Was Determined to Be the Optimum Content of WSO. the Molecular Dynamics Results Indicated that as the Amount of WSO Increased, the Total Volume and the Occupied Volume Increased, While the Free Volume Decreased. the Volume Fusion Parameters Increased Significantly with an Increase in the WSO Content. This Showed that WSO Effectively Improved the Diffusion Capacity of Rejuvenated Binders

Kinetic analysis on premixed oxy-fuel combustion of coal pyrolysis gas at ultra-rich conditions: Selective combustion and super-adiabatic flame temperatures

Oxy-fuel combustion of coal pyrolysis gas has recently been proposed to serve as internal heat source of a vertical low-temperature pyrolysis furnace, in order to make the output pyrolysis gas nearly free of nitrogen and widely useful. To keep the pyrolysis temperature and the heat carrier gas volume unchanged from air combustion to oxy-fuel combustion, the equivalence ratio has to be increased up to 8. To explore the flame temperature and species variation at this ultra-rich condition, freely propagating premixed oxy-fuel flames of a typical coal pyrolysis gas at equivalence ratios of 0.5–10 are numerically studied with detailed chemistry. It is found that super-adiabatic flame temperatures (SAFT) occur at equivalence ratios larger than 3 for the considered pyrolysis gas and the SAFT magnitude is 294 K at equivalence ratio of 8. Due to the high H2 mole fraction (46%) in the pyrolysis gas, preferential diffusion plays a negligible role in the SAFT feature. Global net production of CO and H2 by the rich combustion only occurs at moderate equivalence ratio ranges, which are 1.5–8 and 3–5.5 respectively for the two species. At equivalence ratio of 8, the three fuel components are all net consumed following the mole ratio of CH4:CO:H2 = 1:0.07:0.84. Kinetic analysis reveals three factors responsible for the reaction mechanism change with the increase in equivalence ratio. Firstly, the lack of H-radical and the decrease in temperature result in the disappearance of the H2 production peak in the initial stage. Secondly, HO2 attack to CO prevails and hence contribution of CO oxidation in the initial stage increases. Thirdly, the long lasting OH attack to CO and H2 leads to the weakened CO and H2 production rate in the final stage.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Fluid Mechanic