Bond of FRP bars in fine-grained alkali-activated concrete

Alkali-activated cement (AAC) is an alternative binder with a promising potential to replace ordinary Portland cement (OPC) and mitigate its environmental issues. The use of fiber-reinforced polymer (FRP) reinforcements with AAC concrete enables the development of corrosion-resistant, environmentally friendly reinforced concrete structures. Bond behavior is critical in reinforced concrete structures and must be thoroughly studied for such new alternative materials. This study employs pullout tests to investigate the bond behavior between FRP bars and fine-grained AAC concrete. Three fine-grained AAC concretes with low to high strength, glass and carbon FRP bars and wrapped, milled, and smooth surface treatments were examined. The effect of bar casting position was also investigated. The compressive strength showed a significant influence on the bond strength. An average bond strength of approximately 18 MPa was observed for both glass and carbon FRP bars when used with 65 MPa concrete. Both the glass and carbon FRP bars with wrapping showed a lower bond strength than their milled FRP bars counterparts. The carbon bars without surface preparation (smooth bars) resulted in a much lower bond strength, around 4 MPa. In terms of casting positions, the bars cast in the middle section of the concrete block showed a higher bond strength than those at the bottom and top. © 2024 The Author(s). Structural Concrete published by John Wiley & Sons Ltd on behalf of International Federation for Structural Concrete

Effect of bioaugmentation on gas production and microbial community during anaerobic digestion in a low-temperature fixed-bed reactor

Low temperature is one of the limiting factors for anaerobic digestion in cold regions. To improve the efficiency of anaerobic digestion for methane production in stationary reactors under low-temperature conditions, and to improve the structure of the microbial community for anaerobic digestion at low temperatures. We investigated the effects of different concentrations of exogenous Methanomicrobium (10, 20, 30%) and different volumes of carbon fiber carriers (0, 10, 20%) on gas production and microbial communities to improve the performance of low-temperature anaerobic digestion systems. The results show that the addition of 30% exogenous microorganisms and a 10% volume of carbon fiber carrier led to the highest daily (128.15 mL/g VS) and cumulative (576.62 mL/g VS) methane production. This treatment effectively reduced the concentrations of COD and organic acid, in addition to stabilizing the pH of the system. High-throughput sequencing analysis revealed that the dominant bacteria under these conditions were Acidobacteria and Firmicutes and the dominant archaea were Candidatus_Udaeobacter and Methanobacterium. While the abundance of microorganisms that metabolize organic acids was reduced, the functional abundance of hydrogenophilic methanogenic microorganisms was increased. Therefore, the synergistic effect of Methanomicrobium bioaugmentation with carbon fiber carriers can significantly improve the performance and efficiency of low-temperature anaerobic fermentation systems

Expression of Inflammatory Factors in Critically Ill Patients with Urosepticemia and the Imaging Analysis of the Severity of the Disease

Urine sepsis is a complex inflammatory response of the body to infection with a high fatality rate. It is one of the main causes of death in noncardiovascular intensive care units. Nevertheless, in daily clinical practice, early sepsis is often not detected. In this paper, discharged cases of urinary sepsis from the Department of Urology and Critical Care Medicine of a university hospital were collected as the observation group, and common urinary tract infection cases were selected as the control group. We sorted and summarized the discharged case information of the observation group and the control group. The results of the study showed that, after renal pelvis perfusion, the expression of HMGB1 protein and mRNA increased, and the expression of TLR4 increased; inhibiting HMGB1 can reduce the expression of inflammatory factors caused by perfusion and reduce the infiltration of neutrophils and macrophages caused by perfusion. In addition, r HMGB1 treatment can promote the expression of inflammatory factors caused by perfusion and aggravate the infiltration of neutrophils and macrophages caused by perfusion. We found that inhibition of HMGB1 can inhibit the expression of TLR4/My D88 signaling molecules and r HMGB1 treatment can enhance the expression of TLR4/My D88 signaling molecules.</jats:p

Obtainment of Lignocellulose Degradation Microbial Community: The Effect of Acid-Base Combination After Restrictive Enrichment

Abstract Acid-base combination is used in some cases expecially after restricted enrichment, and has created many lignocellulose-degrading communities. While how it worked is not well understood. In this study, compost was used as inoculum source. Induced community structure changes were analyzed with high throughput sequencing to elucidate the formation processes and determine the mechanisms of acid-base combination. We found that after restricted enrichment, retaining primarily bacteria not only included that could decompose and utilize lignocellulose, such as Clostridium and Pseudomonas, but also synergistic microbiota such as Pseudoxanomonas and Alkalobacillaceae. When the proportion of these two types of bacteria was not balanced, the degradation ability of the microbial community was low or pH changes of it did not compound regular changes , which maybe lead to the failure of restricted enrichment. Microbial communities were re-constituted by acid-base combination, whereby the degrading and synergistic strains were adjusted to a more appropriate proportion. Acid-base combination fixed the instability of microbial communities caused by randomness of restrictive screening enrichment. In this study, the mechanism of acid-base combination was analyzed, which enriched the theoretical system of restricted culture, and provided an effective and controllable technical method for obtaining high-quality lignocellulose-degrading microbial community resources.</jats:p

Changes of Coastal Wetland Ecosystems in the Yellow River Delta and Protection Countermeasures to Them

Coastal wetlands in the Yellow River Delta are typical new wetland ecosystems in warm temperate zone. In recent years, influenced by natural and human factors, these coastal wetlands in the Yellow River Delta have undergone changes of landscape fragmentation, vegetation degradation, pollution, species reduction, and harmful exotic species invasion. These changes have influenced sustainable and healthy development of marine economy of the Yellow River Delta. To protect natural ecological environment of the Yellow River Delta, the authors recommended that it should establish and improve policies, laws and regulations of wetland protection; carry out wetland resource investigation and assessment and monitoring; strengthen comprehensive protection and control of wetland; reduce wetland degradation and promote sustainable use of wetland