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Wearable electronic gadgets have always been in great demand for multifunctional flexible strain sensors. However, developing a flexible strain sensor with excellent characteristics such as high sensitivity, wide sensing range, and excellent durability continues to be a significant challenge. On the one hand, the two-performance metrics of high sensitivity and wide sensing range are mutually exclusive, because the former requires significant structural changes under small strains, whereas the latter necessitates the preservation of morphological integrity under large deformations. On the other hand, the usage of flexible strain sensors is invariably accompanied by the destruction of the conductive network, rendering the device unusable for an extended period of time. Here, based on the unique strain related microcrack structure of the Ti 3 C 2 T x (MXene)/carbon nanotubes (CNTs) synergistic interaction and the shape memory property of ethylene vinyl acetate polymer (EVA), a MXene/CNTs/EVA fiber strain sensor was innovatively designed and prepared by swelling ultrasonic method. The results showed that the sensor combines a large strain sensing range (190%), high sensitivity (82.5), ultra-fast response speed (178.9 ms), and excellent durability and stability (> 10,000 cycles). What is even more exciting is that if the strain sensor is failure, it can be repaired by heating for 2 min or infrared irradiation for 5.4 s, and the mechanical and electrical properties of the repaired sensor can be restored to 92% and 94% of the original. In addition, this strain sensor can accurately monitor subtle and large movements of the human body (including elbow and finger bending, speaking, and mouth opening/closing), even if the damaged MXene/CNTs/EVA fiber strain sensor has been repaired. The self-repairing MXene/CNTs/EVA composites fiber-based shape memory matrix has excellent potential as a wearable strain sensor. [Display omitted] • The MXene/CNTs/EVA fiber strain sensors exhibit excellent elasticity, and electrical conductivity. • The fiber strain sensors have wide strain sensing range, high sensitivity, and high stability. • The fiber strain sensors can be repaired by heating and infrared light irradiation. • The fiber strain sensors can detect a wide range of human motion and weak physiological signals. [ABSTRACT FROM AUTHOR]

Information about the thermal conductivity of sprayed concrete is useful for calibration exercises using sprayed panels, where heat flows need to be estimated, and future enhancements to the method to include estimates of concrete temperature across the thickness of the lining. However, the necessary information about thermal conductivity of sprayed concrete is rare, and no information about the early age thermal conductivity of sprayed concrete has been found. The thermal conductivity of sprayed concrete aging from five hours after casting to 20 days was continuously measured by a transient method. Thermal conductivity was found to be higher than expected at early age and decreased to the mature value as the concrete cured. Based on these results it is hypothesized that early age thermal conductivity is mainly influenced by free water content, while at a mature stage the key determinants are the structural features of the cement matrix. Thermal conductivity is discovered to have an exponential relationship with density, regardless of mix constituents. A convenient numerical approach is proposed to estimate thermal conductivity for concretes and its accuracy has been verified by data from tests on a wide range of concretes with density ranging from 0.2 g/cm 3 to 2.5 g/cm 3 . [ABSTRACT FROM AUTHOR]

It has become a common practice to use composite cement instead of pure Portland cement in many construction applications, then acknowledging the long-term microstructures and compositions of the composites, to ensure a long term stable performance and durability, becomes essential. Thus, this paper is presenting the characterisation of three 20-year-old cement-GGBS-blended pastes which experienced a curing history of at 40 °C for the first five years and then room temperature for the rest years. The main existed phases included C–S–H gel, portlandite, AFm, and hydrotalcite-like phase as hydration products, as well as the products from the carbonation occurring during storage, including ettringite (this ettringite was from the carbonation of AFm.), calcite, vaterite, hemicarbonate and monocarbonate. The comparison among the results obtained for three pastes indicated that increasing GGBS contents enhanced the substitution of bridging SiO 4 4− tetrahedra by AlO 4 5− tetrahedra in the aluminosilicate structure of C–S–H gel, the incorporation of proton ions into the chains to balance the charge differences caused by the substitution, as well as the chain growth. The chain length was found to be direct proportional to GGBS contents, which was enhanced by higher curing temperatures. Through comparing to the results obtained for parallel pastes but hydrated at room temperature for the whole 20 years, a similar hydration degree was observed for OPC in each paste, but higher hydration degree for GGBS in the paste with the experience of hydration at 40 °C, as well as morphological and compositional differences were caused by the different hydration histories. In addition, calcium hydroxide functioning as “a catalyst” in the process of pozzolanic reaction of GGBS was suggested by similarity between calcium contents but different hydration degrees of GGBS in both parallel pastes with and without hydration experience at 40 °C. [ABSTRACT FROM AUTHOR]

• Power and duration were the key parameters of nonisothermal microwave curing. • Non-thermal effects were initiated by threshold energy. • Thermal effects had stronger acceleration impact than nonthermal effects. • Nonthermal effects increased the formation of 3D aluminosilicate chains. Based on the finding of little understanding of acceleration mechanism of microwave curing, this work studies the mechanism in terms of thermal and nonthermal effects of microwaves on mortars. Mortar is cured by regimes designated with varied curing intensity in order to distinguish thermal and nonthermal effects, which are normally difficult to be told apart. They are distinguished by the inconsistency of temperature and compressive strength evolution kinetics. Microstructural characteristics are studied to explore an insight to the effects. It is found that thermal effects constantly exist and nonthermal effects are initiated by threshold energy. Although they are both responsible for accelerating mortar hardening, thermal effects are more effective. Nonthermal effects increase the branching and cross-linking of aluminosilicate chains. The resultant three-dimensional C-S-H morphology is detrimental for packing densely at nanoscale, which may explain the less acceleration effectiveness of nonthermal effects on strength development. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to evaluate whether patients with nonalcoholic fatty liver disease (NAFLD) have more myocardial malperfusion on CT myocardial perfusion imaging (CT-MPI), as well as to further assess if NAFLD is a predictor of myocardial ischemia independently. Methods: A total of 310 consecutive patients were included for analysis. All patients were divided into two groups according to the presence or absence of NAFLD, which was diagnosed by noncontrast cardiac CT partially covered liver and spleen. Clinical characteristics as well as imaging features including coronary artery calcium score, CCTA, and CT-MPI findings were analyzed. Univariable and multivariable logistic regression analyses were used to find out the relationship between NAFLD and myocardial ischemia. Results: NAFLD (unadjusted hazard ratio [HR]: 2.4, 95% confidence interval [CI]: 1.2 to 4.4, p = 0.008), male (HR: 2.6, 95% CI: 1.5 to 4.5, p = 0.001), obstructive CAD (HR: 2.3, 95% CI: 1.3 to 4.2, p = 0.004), and FAI ≥ −70.1 HU (HR: 3.1, 95% CI: 1.8 to 5.5, p < 0.001) were associated with myocardial ischemia in univariable analysis. After adjusting for traditional CAD risk factors and CT characteristics in the multivariable regression analysis, NAFLD (HR: 2.3, 95% CI: 1.2 to 4.4, p = 0.016) was an independent predictor of myocardial ischemia. Conclusion: Our data suggest that myocardial ischemia was more prevalent in patients with NAFLD, and NAFLD is a predictor of myocardial ischemia independent of traditional cardiovascular risk factors and CCTA characteristics. Key Points: • NAFLD patients had higher calcium score, incidence of obstructive coronary artery disease, grade of CAD-RADS, quantitative plaque characteristics, and incidence of fat attenuation index ≥ −70.1 HU. • NAFLD patients had a higher incidence of myocardial ischemia, myocardial hypoperfusion, and hypoperfusion myocardial segments ratio. • NAFLD was a predictor of myocardial ischemia, independent of traditional cardiovascular risk factors, and CCTA characteristics. [ABSTRACT FROM AUTHOR]

In this study, the self-healing properties of mortars mixed with a crystalline admixture (CA) and superabsorbent polymer (SAP) were investigated. By conducting uniaxial compressive strength tests on the mortar samples, the effects of the two admixtures and different admixture ratios on the initial compressive strength and strength repair ability at different curing ages of the mortar after pre-cracking were investigated. To verify the results, optical microscopy, scanning electron microscopy, and X-ray diffraction were used for microscopic observation of the cracks and their healing products. The results of this study show that CA, which generates dense substances through chemical reactions, has obvious advantages in the self-healing of microcracks and has a greater effect on the flexural strength of mortar compared with SAP, which can effectively fill wider cracks, reduce the width of cracks through physical expansion, and has a greater impact on the compressive strength of mortar compared with CA. Compared with ordinary mortar, mortar mixed with CA only, and mortar mixed with SAP only, the appropriate amounts of both CA and SAP can effectively combine the advantageous effects of CA and SAP and optimise the self-healing effect of mortar so that its self-healing rate reaches 103%. The self-healing filler, consisting mainly of calcium silicate and calcium carbonate, is generated in cracks and enhances the repair strength of the mortar so that the strength of the mortar reaches 46 MPa. [ABSTRACT FROM AUTHOR]

[Display omitted] • The development on PFRC during three decades are studied. • PFRC has various advantageous properties over ordinary concrete. • Plant fibre reinforcement causes the loss of compressive strength and durability. • Premodification on plant fibres improves the inferior properties of PFRC. • Theoretical studies of PFRC are still lacking. As one of the most important supporting technologies to economic development and urbanisation, concrete becomes a crucial link to reduce the global carbon emission and confronts with an unprecedented challenge of decarbonation. The reinforcement by plant fibres in concrete is one of promising approaches to decarbonise concrete. This paper combines scientometric and manual analysis to study the research progress on plant fibre reinforced concrete (PFRC), revealing the development scale, the prevailing research domains and focuses on PFRC and the knowledge progress of PFRC. The main challenges confronted by PFRC are discussed and future research scope are proposed. [ABSTRACT FROM AUTHOR]

• Isothermal microwave curing was effective for preparing RPC. • Microwaves accelerated strength development significantly. • The optimal curing process was obtained. • The contributed reactions were identified. A combined application of microwaving curing and reactive powder concrete (RPC) may provide an accelerated development of outstanding mechanical and physical properties, which has great potential to improve the quality and efficiency of production. In this work, a custom-made microwave oven was used to isothermally cure RPC with steel fibre reinforcement at 40 °C, 60 °C and 80 °C for 30 min. Compared to phased nonisothermal microwave curing, the isothermal microwave curing is equally effective, yet more energy efficient to operate and easier to control. The microwave-cured specimens at 1 day gained up 72.0% and 127.6% of the 28 days compressive and flexural strength achieved with standard curing, respectively. The acceleration rates varied with material characteristics and initial temperatures. The characterisation data obtained from STA, XRD and SEM-EDS analysis indicated that the beneficial effects of microwave curing temperature on strength development were due to the accelerated cement hydration and pozzolanic reaction of silica fume. The products resulting from this acceleration strengthened the interfacial zone between hydrated regions and aggregates, and the interfacial zone between the cement and silica fume. Besides C-S-H, AFm, AFt, CH, C C - , Al-tobermorite, a CO 3 2−-contained fukalite-like phase was found to be formed, which may be produced by the pozzolanic reaction of silica fume at the expense of calcium carbonate under microwave curing. [ABSTRACT FROM AUTHOR]

Whether stress CT myocardial perfusion imaging (CT-MPI) improves risk assessment in patients with diabetes mellitus (DM) remains unexplored. We aimed to evaluate the prognostic value of coronary CT angiography (CCTA) and stress CT-MPI in suspected coronary artery disease (CAD) patients with and without DM. A total of 334 patients with suspected CAD who underwent CCTA and stress CT-MPI from May 2020 to July 2021 were retrospectively analyzed. The endpoint was major adverse cardiovascular events (MACEs). Multivariable Cox regression analysis was used to evaluate the risk factors for MACEs, including clinical risk factors, CCTA characteristics and CT-MPI characteristics. After a median follow-up of 21 months,15 patients of the DM group and 16 patients of the non-DM group experienced MACEs. Multivariate Cox stepwise regression analysis showed that abnormal perfusion myocardial segments ratio was associated with MACEs after adjusting for clinical risk factors and CCTA characteristics in all patients (HR:1.023, p < 0.001), DM group (HR:1.024, p = 0.008) and non-DM group (HR:1.028, p = 0.003). By adding CT-MPI characteristics to CCTA characteristics and clinical risk factors, the global chi-square for predicting MACEs increased from 62.24 to 78.84 in all patients (p < 0.001), from 19.18 to 27.30 in DM group (p = 0.004) and from 39.51 to 48.65 in non-DM group (p = 0.003); the increment of C-index in all patients, DM group and non-DM group were 0.018, 0.054 and 0.019, respectively. In all patients and those with and without DM, CT-MPI has incremental prognostic value over clinical risk factors alone or combined with CCTA characteristics in predicting MACEs. [ABSTRACT FROM AUTHOR]

Abstract: The tidal stream turbine is the major device we use to obtain the kinetic energy of tides. The blades of the rotor are one of the essential parts which can convert tidal current energy into mechanical energy. Now most horizontal-axis turbine blade design theories are mostly based on the BEM (blade element momentum) theory and Glauert theory (e.g., WTperf, GHbladed). This paper comes up with a new method – Schmitz design. This method is easier, but they have the same physical philosophy. Also we change the chord length distribution to adapt the low stream velocity. This new hydrofoil increases the startup torque, improves the total performance of the turbine and decreases the thrust coefficient. At the same time we consider the incipient cavitations, tip loss and airfoil loss. We compare the design results with the experimental data in the literature. This method can satisfy the requirement of the design. [Copyright &y& Elsevier]