Recycling of waste concrete has become an important issue worldwide due to the continued increase of construction wastes. Also, the growing global construction activities urge to find sustainable ...resources to replace natural materials for the production of concrete. In the past few decades, many researches have been carried out on the use of recycled aggregate (RA) derived from construction and demolition wastes to produce concrete products. This paper reviews the previous findings on the effects of use of RA on durability of concrete. In general, the amount of adhered mortar and the quality of the original concrete have a significant effect on the properties of resulting concrete. The increase of RA content and w/c ratio results in poorer durability of concrete. In comparison, the negative effect of recycled fine aggregate is more obvious than that of recycled coarse aggregate. The use of pozzolanic materials either for surface coating of RA or intermixed within the concrete are effective and feasible to improve the overall durability of concrete. Recent researches on CO2 treatment indicate that it can enhance the properties of RA and durability of concrete significantly.
Carbonates and bicarbonates are two groups of accelerators which can be used in sprayed concrete. In this study, the effects of the two accelerators sodium carbonate (Na₂CO₃) and sodium bicarbonate ...(NaHCO₃) (0%, 1%, 2%, 3%, and 4% by weight of ordinary Portland cement OPC) on the properties of OPC paste were compared. The results show that both of them could accelerate the initial and final setting time of OPC paste, but the effect of the two accelerators on the compressive strength were different. After 1 day, sodium bicarbonate at 3% had the highest strength while sodium carbonate at 1% had the highest strength. After 7 days, both of the two accelerators at 1% had the highest compressive strength. After 28 days, the compressive strength decreased with the increase of the two. The improved strength at 1 and 7 days was caused by the accelerated formation of ettringite and the formation of CaCO₃ through the reactions between the two with portlandite. The decrease of strength was caused by the Na⁺ could reduce the adhesion between C-S-H gel by replacing the Ca
. NaHCO₃ was found be a better accelerator than Na₂CO₃.
Water was regarded as the particle that its size is the minimum. According to the size of particle, the particles in the fresh mortar were divided into three grading: water, powder, and sand. The ...physical model of fresh mortar were established through the two-stage filling of particles, that is to say, the paste fills the voids of sand particles, water fills the voids of the powder particles in the remainder paste, and the remainder water is called as the surplus water. To calculate the remainder water in fresh mortar, the mathematical model of the packing was established to quantitatively characterize the physical filling effect of AMF in fresh mortar. On this basis, the manufactured fine aggregate (MFA) mortars with different water-to-cement (W/C) ratio (0.45, 0.50, 0.60, and 0.65) and different sand-to-cement (S/C) ratio (3:1, 2:1, and 1:1) were taken as the research object, and the influences of the AMF on the surplus water, bulk density, and mechanical property were studied when its content is respectively 0 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, and 30 wt% in MFA. The results show: the physical filling effect of AMF in fresh mortar can be better characterized with the volume of surplus water in fresh mortar, and the influence of the AMF on the packing of fresh mortar is better consistent with the bulk density of fresh mortar and the mechanical property of hardened mortar. This is the good references for the packing characterization of fresh mortar and the content determination of AMF in MFA.
Under the background of the 4th industrial revolution, digital twin technology has been constantly integrated with the power grid business. Power grid will build a digital twin grid covering the ...whole physical grid and production process. This paper first proposes the digital power grid based on digital twin. A closed-loop power grid data empowerment system is introduced to define the digital power grid based on digital twin, the three features and properties are described to enrich the digital power grid connotation. It constructs the digital power grid architecture including physical power grid, perception layer, transport layer, data layer, platform layer and application layer. The key technologies are also discussed to embody digital power grid.
•Effects of Ca(HCO3)2 on the fresh and harden properties of OPC paste were studied.•Ca(HCO3)2 can accelerate the early age hydration of cement paste.•Ca(HCO3)2 can react with portlandite and form ...calcite to fill the pores of OPC paste.•Optimum content of addition of Ca(HCO3)2 was found to be 1% by weight of OPC.
Bicarbonates can be used as accelerators to enhance the early age properties of cementitious materials. Bicarbonates like KHCO3 and NaHCO3 could form strong alkali (KOH, NaOH) and cause potential risk of alkali-silica reaction. Ca(HCO3)2 could serve as a better accelerator than these bicarbonates because of formation of CaCO3 and Ca(OH)2, which are usually found in cementitious system. The effects of Ca(HCO3)2 on the hydration and physical properties of OPC paste were studied through heat of hydration, setting time, extension degree, compressive strength, pore size distribution, TG-DTA, XRD and SEM tests. The results showed that Ca(HCO3)2 can accelerate the formation of ettringite and CO2-AFm at the initial stage, and increase the early age strength of OPC paste. Besides, Ca(HCO3)2 was found to accelerate the hydration of C3S and C2S at a later stage and modify the pore structure of OPC paste. The reaction between Ca(HCO3)2 and portlandite formed CaCO3, which could fill the harmful pores in cement paste. The optimum content of Ca(HCO3)2 was found to be 1% by weight of cement, and further increase of Ca(HCO3)2 could decrease the compressive strength by increasing the harmful pores.
Grouting materials are used frequently in grouting reinforcement projects, such as mining and coastal engineering. Double liquid grouting materials are mostly used because of the fast setting and ...high early strength properties when the two slurries are mixed together but high fluidity when the two slurries are separated. In our study, double liquid grouting materials were developed from CSA cement (slurry A), quicklime and fluorgypsum (slurry B). Aluminum sulfate was added in slurry B in order to counteract any adverse effects caused by the fluorgypsum, such as the decreased early compressive strength and the prolonged setting time. The effects of aluminum sulfate content and the quicklime/fluorgypsum ratio on the setting time, hydration heat, and compressive strength of the double liquid grouting materials were investigated, and the hydration products were characterized through thermogravimetry-differential thermal analysis (TG-DTA), X-ray Diffraction (XRD), and Scanning Electron Microscope (SEM) tests. The results show that the addition of aluminum sulfate can shorten the setting time and increase compressive strength at both early and later ages. Considering the setting time and compressive strength of double liquid grouting material at the same time, the optimum content of aluminum sulfate was found to be 2%, and the optimum ratio of quicklime/fluorgypsum was found to be 2:8. The values of the optimum content of aluminum sulfate and ratio of quicklime/fluorgypsum were verified from theoretical analysis.
Brain image segmentation algorithm based on deep learning is a research hotspot at present. In this paper, firstly, the significance of brain image segmentation and the content of related brain image ...segmentation algorithm are systematically described, highlighting the advantages of brain image segmentation algorithms based on deep learning. Then, this paper introduces current brain image segmentation algorithms based on deep learning from three aspects: the brain image segmentation algorithms based on problems existent to brain image, the brain image segmentation algorithms based on prior knowledge guidance and the application of general deep learning models in brain image segmentation, so as to enable researchers in relevant fields to understand current research progress more systematically. Finally, this paper provides a general direction for the further research of brain image segmentation algorithm based on deep learning.
CD147 is an important glycoprotein that participates in the progression of diverse cancers. This study aims to explore the specific function of CD147 in lung adenocarcinoma (LUAD) and to reveal ...related downstream molecular mechanisms.
Followed by silencing of CD147, the viability, migration, invasion, and apoptosis of LUAD cells were measured by CCK8, wound healing, transwell assay, and flow cytometer, respectively. The expression of CD147 and two markers of lipid metabolism (FASN and ACOX1) were detected by qRT-PCR. A xenograft tumor model was constructed to investigate the function of CD147 in vivo. Then transcriptome sequencing was performed to explore the potential mechanisms. After measuring the expression of Rap1 and p-p38 MAPK/p38 MAPK by western blot, the changes of CD147 and lipid metabolism markers (FASN, ACOX1) was detected by Immunohistochemistry. Moreover, a Rap1 activator and a Rap1 inhibitor were applied for feedback functional experiments.
CD147 was up-regulated in LUAD cells, and its silencing inhibited cell proliferation, migration, invasion, lipid metabolism dysregulation and promoted apoptosis, while overexpression of CD147 showed the opposite results. Silencing of CD147 also inhibited the growth of tumor xenografts in mice. Transcriptome sequencing revealed 834 up-regulated differentially expressed genes (DEGs) and 602 down-regulated DEGs. After functional enrichment, the Rap1 signaling pathway was selected as a potential target, which was then verified to be blocked by CD147 silencing. In addition, the treatment of Rap1 activator weakened the inhibiting effects of si-CD147 on the proliferation, migration, invasion, and lipid metabolism in LUAD cells, while the intervention of RAP1 inhibitor showed the opposite results.
Silencing of CD147 inhibited the proliferation, migration, invasion, lipid metabolism dysregulation and promoted apoptosis of LUAD cells through blocking the Rap1 signaling pathway.
Melatonin is a well-known anti-inflammatory and antioxidant molecule, which plays a crucial role in various physiological functions. In this study, mice received a single dose of 15 Gy radiation ...delivered to the lungs and daily intraperitoneal administration of melatonin. After 7 days, mice were processed to harvest either bronchoalveolar lavage fluid for cytokine assays or lungs for flow cytometry and histopathological studies. Herein, we showed that melatonin markedly alleviated the oxidative stress and injury, especially suppressing the infiltration of macrophages (CD11b+CD11c−) and neutrophils (CD11b+Ly6G+) to the irradiated lungs. Moreover, in the irradiated RAW 264.7 cells, melatonin blocked the NLRP3 inflammasome activation accompanied with the inhibition of the IL-1β release and caspase-1 activity. However, melatonin restored the downregulated miR-30e levels. Quantitative PCR analysis of miR-30e and NLRP3 indicated the negative correlation between them. Notably, immunofluorescence staining showed that overexpression of miR-30e dramatically diminished the increased NLRP3 expression. Luciferase reporter assay confirmed that NLRP3 was a target gene of miR-30e. Western blotting revealed that transfection with miR-30e mimics markedly reduced the expressions of NLRP3 and cleaved caspase-1, whereas this phenomenon was reversed by the miR-30e inhibitor. Consistent with this, the beneficial effect of melatonin under irradiated exposure was blunted in cells transfected with anti-miR-30e. Collectively, our results demonstrate that the NLRP3 inflammasome contributed to the pathogenesis of radiation-induced lung injury. Meanwhile, melatonin exerted its protective effect through negatively regulating the NLRP3 inflammasome in macrophages. The melatonin-mediated miR-30e/NLRP3 signaling may provide novel therapeutic targets for radiation-induced injury.
PDF
