FRP structure design method based on equality of stiffness: case study and practice

Nowadays, Fiber reinforced polymer materials are getting widely used in civil engineering. They have some advanced engineering characters like high stiffness-to-weight ratio, high strength-to-weight ratio, anti-electromagnetic interference, electrical isolation and its long time durability. Metal and concrete, those main kinds of construction material, are prone to be failed before the structure service life because of the environmental attacks. Those harsh attacks are oxidization, acidification, high temperature and alkali corrosion. After the maintenance methods like isolating the attacks or protecting plastic skins, the interfaces between the protections are easily to be cracked and it caused the same worry on durability problems. Fiber reinforced polymer stands for a new era of civil engineering and surely the traditional material can be substituted by fiber reinforced polymer. This paper wants to unfold a case study on how fiber reinforced polymer worked in civil structures

Parameter selection and performance comparison of particle swarm optimization in sensor networks localization

Localization is a key technology in wireless sensor networks. Faced with the challenges of the sensors\u27 memory, computational constraints, and limited energy, particle swarm optimization has been widely applied in the localization of wireless sensor networks, demonstrating better performance than other optimization methods. In particle swarm optimization-based localization algorithms, the variants and parameters should be chosen elaborately to achieve the best performance. However, there is a lack of guidance on how to choose these variants and parameters. Further, there is no comprehensive performance comparison among particle swarm optimization algorithms. The main contribution of this paper is three-fold. First, it surveys the popular particle swarm optimization variants and particle swarm optimization-based localization algorithms for wireless sensor networks. Secondly, it presents parameter selection of nine particle swarm optimization variants and six types of swarm topologies by extensive simulations. Thirdly, it comprehensively compares the performance of these algorithms. The results show that the particle swarm optimization with constriction coefficient using ring topology outperforms other variants and swarm topologies, and it performs better than the second-order cone programming algorithm

CMB Temperature and Matter Power Spectrum in a Decay Vacuum Dark Energy Model

In this paper, a decay vacuum model $\bar{\rho}_\Lambda=3\sigma M_p^2H_0 H$ is revisited by detailed analysis of background evolution and perturbation equations. We show the imprints on CMB temperature and matter power spectrum from the effective coupling terms between dark sectors by comparing to the standard cosmological constant model and observational data points (WMAP7 and SDSS DR7). We find that the decay vacuum model can describe the expansion rate at late times as well as the standard cosmological constant model but it fails to simultaneously reproduce the observed CMB and matter power spectrum. Its generalization $\bar{\rho}_\Lambda=3M_p^2(\xi_1 H_0 H+\xi_2 H^2)$ is also discussed. Detailed analysis of the background evolution shows that the dimensionless parameter $\xi_{2}$ would be zero to avoid the unnatural 'fine tuning' and to keep the positivity of energy density of dark matter and dark energy in the early epoch

Effectiveness and safety of non-vitamin K oral anticoagulants versus warfarin in patients with atrial fibrillation and previous stroke: A systematic review and meta-analysis

Introduction: Current evidence regarding the clinical outcomes of non-vitamin K oral anticoagulants (NOACs) versus warfarin in patients with atrial fibrillation (AF) and previous stroke is inconclusive, especially in patients with previous intracranial haemorrhage (ICrH). We aim to undertake a systematic review and meta-analysis assessing the effectiveness and safety of NOACs versus warfarin in AF patients with a history of stroke. Methods: We searched studies published up to December 10, 2022, on PubMed, Medline, Embase, and Cochrane Central Register of Controlled Trials. Studies on adults with AF and previous ischaemic stroke (IS) or IrCH receiving either NOACs or warfarin and capturing outcome events (thromboembolic events, ICrH, and all-cause mortality) were eligible for inclusion. Results: Six randomized controlled trials (RCTs) (including 19,489 patients with previous IS) and fifteen observational studies (including 132,575 patients with previous IS and 13,068 patients with previous ICrH) were included. RCT data showed that compared with warfarin, NOACs were associated with a significant reduction in thromboembolic events (odds ratio [OR]: 0.85, 95% confidence interval [CI]: 0.75-0.96), ICrH (OR: 0.57, 95% CI: 0.36-0.90), and all-cause mortality (OR: 0.88, 95% CI: 0.80-0.98). In analysing observational studies, similar results were retrieved. Moreover, patients with previous ICrH had a lower OR on thromboembolic events than those with IS (OR: 0.66, 95% CI: 0.46-0.95 vs. OR: 0.80, 95% CI: 0.70-0.93) in the comparison between NOACs and warfarin. Conclusions: Observational data showed that in AF patients with previous stroke, NOACs showed better clinical performance compared to warfarin and the benefits of NOACs were more pronounced in patients with previous IrCH versus those with IS. RCT data also showed NOACs are superior to warfarin. However, current RCTs only included AF patients who survived an IS, and further large RCTs focused on patients with previous ICrH are warranted.</p