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This study uses slag (SL), fly ash (FA), and carbon fiber (CF) as raw materials to fabricate a conductive geopolymer, exploring the impact of CF content on its workability and mechanical performance. The conductivity and pressure sensitivity performance of the geopolymer are tested using an embedded four‐electrode method. The findings indicate that the incorporation of CF reduces the fluidity of the geopolymer and shortens its setting time. With the increase of CF content, the compressive strength increases first and then decreases, while the flexural strength increases gradually when the CF content is 0.2 v%, the percolation threshold is reached, and the resistivity is 268 Ω·cm. The geopolymer exhibits good pressure sensitivity performance under both monotonic and cyclic loading. With a stress amplitude of 15 MPa and a loading rate of 1 kN/s, the specimen's resistance change rate can reach −38.4%. The pressure sensitivity performance is optimal, with good repeatability and stability. [ABSTRACT FROM AUTHOR]

Objective: To explore the mechanical properties of weak expansive soil under different moisture contents and confining pressures. Methods: The triaxial remolded soil samples with different moisture contents (14%, 16%, 18%, and 20%) were prepared for the obtained Nanyang weak expansive soil. Four groups of 16 consolidated drained triaxial shear tests with a confining pressure of 50, 100, 200, and 300 kPa were carried out to study the effects of confining pressure and water content on the deviatoric stress and pore pressure of weak expansive soil with strain. Results: The study showed that the shear strength of weak expansive soil samples gradually increased with the increase of the water content, but its increase nonlinearly decreased as the confining pressure increased. When the axial strain was small, the pore pressure significantly increased, and the pore pressure increased tended to be stable slowly and gradually as the axial strain gradually increased. Therefore, the research results could be used to avoid the diseases caused by the characteristics of weak expansive soil in engineering construction and provide theoretical references for improving engineering foundations in weak expansive soil areas. [ABSTRACT FROM AUTHOR]

To reduce the amount of ordinary concrete and then reduce carbon dioxide emission, improving the engineering application range of self-compacting fly ash concrete (FASCC), this study explored the bond–slip traits between FASCC and a steel tube. Six samples were created, and bond–slip push-out tests were performed with varying concrete strength grades and steel tube internal setups. Digital image correlation (DIC) technology was applied to track the surface strain of four samples throughout the experiment. The results show that the outer surface of the steel tube stays mostly undistorted after the concrete is pushed out. Prior to reaching peak load, the load–slip curves of each specimen exhibit a primarily linear load–displacement relationship. Post-peak, the curves diverge into two distinct patterns, namely a sudden drop and a gradual decline. As the strength grade of the inner concrete increases, the interfacial bond between the steel tube and FASCC improves. Additionally, under the same conditions, the internal structure of the steel tube significantly enhances bonding strength. The FA40-Z specimen shows a maximum load that is 25.6% and 53.7% higher than the FA40-G and FA40-C specimens, respectively. The strain evolution patterns of steel tubes within FASCC and regular self-compacting concrete demonstrate similar characteristics. These observations provide valuable insights for the application of FASCC in engineering projects. [ABSTRACT FROM AUTHOR]

Chemical imaging applications using Laser Induced Breakdown Spectroscopy (LIBS) involve laser ablation sampling at interfaces or boundaries between materials with different thermophysical and optical properties, leading to the formation of two initially isolated plasmas. The mechanisms of mixing in these plasmas and their direct implications on spectral emission and chemical imaging remain largely unknown. We investigate the mixing dynamics of isolated plasmas produced using femtosecond (fs) laser pulses at the interface between two different model Cu and Sn–Pb samples. Specifically, we study the spatial and temporal mixing dynamics and outer plasma expansion dynamics of the fs plasma components. The time-resolved degree of component mixing, horizontal and vertical expansion, mixing speed, and temperature and electron density of the heterogeneous plasma are characterized. Mixing processes are initiated early on,

This study explored the influence mechanism on the water resistance of magnesium phosphate repair mortars. The fluidity, setting time, mechanical properties, water resistance, and interfacial bonding strength of red mud–modified magnesium phosphate repair mortars (RMPMs) were systematically investigated. Through capillary absorption tests, the effect of the water-binder ratio (W/B) on the water transfer characteristics was explored, and then the actuating mechanism of capillary porosity and capillary absorption coefficients on water resistance was clarified. The results show that the fluidity and setting time of RMPM increase with the increase of W/B. When W/B increased from 0.18 to 0.20, the compressive strength, flexural strength, strength retention, and interfacial bonding strength of RMPM changed little and decreased linearly. And the interfacial bonding strength of RMPM was significantly reduced after 7 days of water curing. The capillary water absorption of RMPM was linear with the square root of time. The capillary absorption coefficient and capillary porosity of the RMPM increased greatly with increasing W/B when the W/B is between 0.20 and 0.28, while the water resistance, mechanical properties, and interfacial bonding property decreased linearly. Variations in W/B changed the capillary pore characteristics of the RMPM, which in turn affected the mechanical properties, capillary water absorption characteristics, and water resistance. [ABSTRACT FROM AUTHOR]

With the improvement in survival rates of low-birthweight and very premature infants, neonatal fungal infection, especially fungal pneumonia, is becoming more and more common, but the diagnosis is always challenging. Recently, lung ultrasound (LUS) has been used to diagnose pneumonia in newborn infants, but not fungal pneumonia. This paper summarizes the ultrasonographic features of seven cases of neonatal fungal pneumonia, such as lung consolidation with air bronchograms, shred signs, lung pulse, pleural line abnormalities, and different kinds of B-lines. It was confirmed that LUS plays an important role in the diagnosis of fungal pneumonia in newborn infants.