High temperature behaviour of glass-vinyl ester stack liner at the operation temperature (20–121°C) was experimentally investigated by measurements on the small specimens and full scale specimens in this paper. Based on the stacking sequences of a typical glass-vinyl ester stack liner, three groups of small specimens were produced to evaluate the degradation of their tensile and compressive strength, the tensile modulus, and the flexural strength and modulus with increasing temperature, and one group of full scale specimens was prepared to measure their properties at room temperature. Furthermore, the ultimate axial tensile stress of a suspended glass-vinyl ester stack liner at various temperatures was derived according to the experimental results from the small specimens and full scale specimens. The high temperature behaviour of composites stack liner from the tests can be used as reference for determining the extreme operation temperature in coal-fired power plants.
Abstract Objectives The molecular mechanism of bone marrow mesenchymal stem cell ( BMMSC ) population growth and proliferation, induced by Isoleucyl‐lysyl‐valyl‐alanyl‐valine ( IKVAV ), was explored in this study. Materials and methods IKVAV peptides were synthesized by the solid‐phase method. Influence of IKVAV on BMMSC population growth and proliferation were investigated by assays of CCK ‐8, flow cytometry, real‐time PCR and western blotting. Results IKVAV peptide was found to induce proliferation and proliferating cell nuclear antigen ( PCNA ) synthesis of BMMSC in a dose‐ and time‐dependent manner. Cell cycle analysis showed that the proportion of IKVAV ‐treated BMMSC in S phase in was higher than controls. Western blot results suggested that mitogen‐activated protein kinase/extracellular signal‐regulated kinase ( MAPK / ERK ) and phosphatidylinositol 3‐kinase/protein kinase B ( PI 3K/Akt) signalling pathways were activated by IKVAV by enhancing phosphorylation levels of ERK 1/2 and Akt in the BMMSC s. Meanwhile, phosphorylation levels of ERK 1/2 and Akt were partially blocked by ERK 1/2 inhibitor (PD98059) and Akt inhibitor (wortmannin), respectively. Conclusions Our results demonstrated that IKVAV stimulated BMMSC population growth and proliferation by activating MAPK / ERK 1/2 and PI 3K/Akt signalling pathways. This study is the first to reveal an enhancement effect of IKVAV peptide on BMMSC at the signal transduction level, and the outcome could provide experimental evidence for application of IKVAV ‐grafted scaffolds in the field of BMMSC ‐based tissue engineering.
In the field of nerve repair, one major challenge is the formation of neuroma. However, reports on both the promotion of nerve regeneration and prevention of traumatic neuroma in the clinical settings are rare in the field of nerve repair. One of the reasons could be the insufficiency in the follow-up system. We have conducted 33 cases of nerve repair using PRGD/PDLLA/β-TCP conduit without any sign of adverse reaction, especially no neuroma formation. Among them, we have selected two cases as representatives to report in this article. The first case was a patient with an upper limb nerve wound was bridged by PRGD/PDLLA/β-TCP conduit and a plate fixation was given. After nearly 3-years' follow-up, the examination results demonstrated that nerve regeneration effect was very good. When the reoperation was performed to remove the steel plate we observed a uniform structure of the regenerated nerve without the formation of neuroma, and to our delight, the implanted conduit was completely degraded 23 months after the implantation. The second case had an obsolete nerve injury with neuroma formation. After removal of the neuroma, the nerve was bridged by PRGD/PDLLA/β-TCP conduit. Follow-up examinations showed that the structure and functional recovery were improved gradually in the 10-month follow-up; no end-enlargement and any other abnormal reaction associated with the characteristic of neuroma were found. Based on our 33-case studies, we have concluded that PRGD/PDLLA/β-TCP nerve conduit could both promote nerve regeneration and prevent neuroma formation; therefore, it is a good alternative for peripheral nerve repair.
AbstractTo determine the mechanical state of a stay cable over its whole life cycle, a desensitized encapsulation structure was designed to increase the range of the fibre optical Bragg grating (FBG) strain sensor. By embedding the FBG-based sensors inside a cable, a smart cable was fabricated. The critical states of the smart cable, from fabrication to service operation, were tested. The force and performance of it were tested by load testing during multi-stage mechanical states. The static load testing results showed that the smart cable had a high survival rate and the force values and trends were consistent with the results of the FBG-based force-testing ring. The dynamic load testing results showed that after 2 million fatigue cycles, the structure still achieved a testing accuracy of 4·5%, the visual appearance of the encapsulated sensors was good, and encapsulation structures had not shifted and were not damaged.
Accurately replicating the structural characteristics of reef limestone is crucial for obtaining quantitatively reliable results using the Discrete Element Method (DEM). However, limited studies have focused on numerical simulations of reef limestone porosity, and those available often fail to capture the detailed pore structure. This paper presents a method to generate a honeycomb-like DEM model of reef limestone by assembling unit cells that mimic the material's unique structure. The proposed approach effectively reproduces the radially oriented pore features of reef limestone while optimizing resolution and minimizing the number of spheres required. This model validation using the Brazilian splitting test simulation demonstrates the feasibility of the proposed model. Future work will apply this method to various reef limestone samples, offering a comprehensive microscale perspective on mechanical properties.
Oily sludge (OS) is a solid waste threatens ecological environment and human health. In this paper, the thermal behavior and emission of gas products during co-combustion of rice straw (R) modified OS (OS5-R5) and coal (C) were investigated using an automatic calorimeter and model analysis. The effect of combustion atmosphere and additives on the gas products emission during the co-combustion of C, R, OS5-R5, and mixed fuels were investigated. The results show that as the content of OS5-R5 increased in mixed fuels, the performance of mixed fuels worsened gradually. When the mass content of OS5-R5 is 30%, the lower heating value (LHV) was about 20MJ/kg, ~16% lower than that of C. The additives controlled pollutant gases emission. The increase of heating rate resulted in an increase of overall combustion performance of mixed fuel by 5.07-time. Similarly, increasing the oxygen concentration led to a 3.09-time increase in the combustion index of the mixed fuel. The adsorption of polar molecules by montmorillonite was conducive to reducing the pollutant gases emission. BaO and CaO hardly affect NOx emission control but reduce H2S and SO2 emissions because BaO and CaO could react with H2S and SO2 to form sulfate resulting in reduced emission.
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