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Mix Proportion Design Method of RAC and Properties of Fresh RA
No full textThis chapter discusses rational methods for mix design specific to RAC, accounting for the unique properties of recycled aggregates. Various approaches are reviewed, including empirical methods, compressible packing models (CPM), particle packing, and rational proportioning based on adhered mortar volume. The study compares the performance of fresh and hardened RAC mixtures using 44 different mix designs. Mechanical properties are correlated with mix variables, and predictive models are proposed. The findings suggest that with proper design adjustments, RAC can achieve strength and durability levels comparable to conventional concrete
A longitudinal investigation of performance and injury outcomes associated with disordered eating in elite athletes.
Get PDFBACKGROUND: Disordered eating is common in elite athletes and may be motivated by perceived performance advantages associated with becoming leaner. However, few studies have examined the performance outcomes associated with disordered eating over time in this population. This study investigated self-reported performance and days missed from training/competition due to injury as longitudinal outcomes of disordered eating. METHODS: Current elite athletes predominantly from Australia and the US (N = 178; 72.4% female, Mage=23.9, SDage=7.0) completed online surveys between March-September 2023 at baseline (T1), and after 6-months (T2; N = 110) and 12-months (T3; N = 91), including measures of demographic data, disordered eating, self-reported performance in training and competition, and days missed due to injury over the last 6-months. T1-disordered eating was examined as a predictor of T2-performance and T2-days missed due to injury via multiple regression controlling for autocorrelations, with multiple imputation to account for data attrition. The relationships over 12-months were examined via multilevel mixed-effects analyses. RESULTS: Greater T1-disordered eating significantly predicted a greater increase in days missed due to injury at 6-month (B = 0.04, 95% CI = 0.01-0.07), but not 12-month, follow-up, controlling for gender. Greater disordered eating was significantly associated with poorer self-reported performance across timepoints (r = - .23, p = .027 to r = - .39, p < .001); however, T1-disordered eating did not predict a significant change in performance over time, controlling for gender. CONCLUSIONS: Disordered eating should not be considered as either normal or necessary to improve athletic performance, but rather a potential pathway towards injuries and absences from training and/or competition. These findings highlight a need for future research investigating outcomes associated with disordered eating across more specific aspects of performance and injury
Mechanical and bond-slip behaviour of ultra-high performance concrete exposed to high temperature
Get PDFThe residual mechanical behaviour, including the steel-concrete bond, was investigated in this research project for Ultra-high performance concrete (UHPC) with compressive strength of 101–134 MPa and maximum aggregate size below 0.04 mm. Specimens were heated to 200, 400, 600, 800 and 1000°C, reinforced with steel, polypropylene (PP), polyvinyl-alcohol (PVA) or hybrid fibres, for a total of six different mixes. Compressive, 4-point and pull-out tests were carried out to evaluate the compressive strength (on cylinders), the tensile strength (in bending) and bond strength, both at ordinary temperature (25°C) and after heating to high temperature and cooling down to room temperature. The test results show that (a) steel fibres guarantee a higher residual strength but fail to prevent UHPC’s thermal spalling; (b) PP fibres are more effective than PVA fibres in controlling thermal spalling; and (c) hybrid fibres (PP + steel fibres) are the most effective in terms of spalling control and residual strength. In general, other hybrid fibres are shown to be unable to control concrete spalling at temperatures around 400°C. As for the tensile strength in bending, long steel fibres have an edge over mixed steel fibres (with different lengths). Contrary to the compressive strength (that starts decreasing at 600°C), the tensile strength continues to increase above 600°C and starts decreasing at 800°C. As for bond performance, in the thermal range 25–1000°C, pullout tests were performed by using 12-mm deformed bars and three different values for the bonded length/bar diameter ratio (L/D = 2, 4 and 6). On the whole, the decay of bond strength with the temperature is similar to that of the compressive strength. Long steel fibres show higher bond strength, whereas mixed steel fibres offer advantages in other stages such as higher initial stiffness. Based on test data, empirical equations are proposed for the bond-slip law in a high-temperature environment
Design optimisation and fundamental characteristics of multiple identical tuned liquid dampers in mitigating structural vibrations
Get PDFResearchers have developed and applied tuned liquid dampers (TLDs) to reduce the vibration of civil structures. Previous studies have focused on using a large number of identical TLDs (single-frequency TLDs) or many multi-frequency TLDs to reduce the structural dynamic response. In those works, the optimal parameters of TLDs were determined through the optimal parameter of equivalent tuned mass dampers. In this study, a new approach is proposed to directly determine the optimal parameters of multiple identical TLDs (MITLD). Furthermore, different aspects including the best configuration control effectiveness, robustness, and sensitivity to changes in the water level of MITLD are explored. Parametric studies are also conducted to find the fundamental characteristics of MITLD and the effective domains of the MITLD’s main parameters. The results obtained from this work agree well with those of earlier research works. Based on this fundamental research, recommendations given include: (1) MITLD is effective in controlling the dynamic response of structures with low natural frequencies, (2) MITLD is very sensitive to the variation of the water level height in TLDs, and (3) a difference in the natural frequency of the main structure leads to a significant performance decrease of the MITLD
Collective Quantum State Tomography: Closed-Form and Numerical Solutions, and Validation
No full textQuantum state tomography QST is a technique for characterizing benchmarking and verifying quantum systems and devices In this paper we focus on collective QST using data from collective measurements performed on multiple copies of the state We propose a closed form solution and provide an analytical characterization of its computational complexity and mean squared error MSE scaling Additionally we reformulate the problem as a sum of squares SOS optimization problem with semialgebraic constraints enabling the application of SOS tools for its solution The effectiveness of the proposed methods is demonstrated through numerical simulations Furthermore we validate the algorithms using two copy collective experimental data where the entangled measurement provides information about the state purity Compared to previous methods our algorithms achieve lower MSEs and approach the collective MSE bound by leveraging this purity information more efficientl
VPAC1 and VPAC2 Receptor Heterozygosity Confers Distinct Biological Properties to BV2 Microglial Cells.
Get PDFMicroglial cells, the resident immune cells of the central nervous system (CNS), are essential for maintaining CNS homeostasis. Dysregulation of microglial function is implicated in the pathogenesis of various neurodegenerative diseases. Vasoactive intestinal polypeptide receptors 1 and 2 (VPAC1 and VPAC2) are G-protein-coupled receptors (GPCRs) expressed by microglia, with their primary ligands being pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP). However, the specific roles of VPAC-type receptors in microglial regulation remain poorly understood. In this study, we generated VPAC1+/- and VPAC2+/- BV2 microglial cell lines using CRISPR-Cas9 gene editing and conducted a series of biological and molecular assays to elucidate the functions of these receptors. Our findings demonstrated that both mutant cell lines exhibited a polarized phenotype and increased migratory activity. VPAC1+/- cells showed enhanced survivability and baseline activation of the unfolded protein response (UPR), a protective mechanism triggered by endoplasmic reticulum (ER) stress, whereas this response appeared impaired in VPAC2+/- cells. In contrast, under lipopolysaccharide (LPS)-induced inflammatory conditions, UPR activation was impaired in VPAC1+/- cells but restored in VPAC2+/- cells, resulting in improved survival of VPAC2+/- cells, whereas VPAC1+/- cells exhibited reduced resilience. Overall, our findings suggest that VPAC1 and VPAC2 receptors play distinct yet complementary roles in BV2 microglia. VPAC2 is critical for regulating survival, ER stress responses, and polarization under basal conditions, while VPAC1 is essential for adaptive responses to inflammatory stimuli such as LPS. These insights advance our understanding of microglial receptor signaling and may inform therapeutic strategies targeting microglial dysfunction in neurodegenerative diseases
Interactive visual communication for cultural learning and preservation: A mixed-methods study of user engagement with China's intangible heritage
Get PDFPlants that Purify the Air: How Indoor Greenery Generates Negative Air ions
No full textDid you know that the air in your home or office might be missing something found in forests and waterfalls – negative air ions (NAIs)? These naturally charged particles can help remove pollutants from the air. New research at the University of Technology Sydney (UTS) explores how common indoor plants could boost NAI production and naturally improving indoor air quality
Task-space fixed-time bipartite tracking control for heterogeneous networked Euler-Lagrange systems
No full textThis paper investigates the bipartite coordinated tracking control problem in the task-space of heterogeneous networked Euler-Lagrange systems in the fixed-time framework. A new neural network-based fixed-time hierarchical control approach is developed mainly under the directed graphs. Specifically, a distributed observer is firstly designed to estimate the desired position and velocity of the system in the fixed-time framework, and the neural network-based controller is proposed on this basis. The effect of system uncertainty is effectively mitigated and the chattering phenomenon is overcome, thus solving the bipartite coordinated tracking control problem of heterogeneous networked Euler-Lagrange systems at the control layer. In addition, the error can be kept within a small convergence region as derived by the fixed-time stability theory. Finally, the feasibility of the proposed control scheme is fully verified by numerical simulation
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