Search

Studies on durability of cementitious materials have focused on harsh environments, but less attention has been paid to low thermal loading situations. In this paper, with the aim of exploring the evolution of internal pore pressure and microcrack extension of cementitious under low thermal environment, cement paste specimens with thermal environment slightly below 100 °C and three water–binder ratios (0.4, 0.45 and 0.5) and four fly ash admixtures (0, 10%, 20% and 30%) were designed. Firstly, the internal pore pressure of the cement paste was tested; secondly, the average effective pore pressure of the cement paste was calculated; and finally, the phase field method was used to explore the expansion of microcracks inside the cement paste when the temperature gradually increased. It was found that the internal pore pressure of the paste showed a decreasing trend as the water–binder ratio and fly ash admixture increased, and the numerical simulation found that the sprouting and development of cracks were delayed when 10% fly ash was added to the cement paste, which was consistent with the experimental results. This work provides a basis for the durability development of concrete under low thermal environment.

A large number of sensors based on Internet of Things (IoT) technology are now widely deployed in artificial intelligence, health care monitoring, air quality monitoring, and other fields. The sensors require high power consumption for real-time monitoring data. Some studies have suggested using solar energy for the primary power source to operate sensors. However, due to uncertain climate change, solar energy supply cannot always provide sufficient voltage to operate sensors. Consequently, some abnormal behavior events frequently occur in the IoT system using solar energy. Abnormal detection is a typical imbalanced learning problem due to the very rare amount of abnormal events. Under such data with skewed class distribution, classic classification models fail to provide reliable classification results with abnormal events. Under this condition, in this paper, deploying solar energy supply, we developed an IoT-based system using Arduino Microcontroller and Banana Pi, in which, the SMOTE-PSO algorithm is utilized to improve classification accuracies on abnormal event data in our system. Finally, two types of SVM kernel functions are used to verify classification capability in the developed IoT system.

We examine the impact of the global financial crisis (GFC) on auditor behaviour in Australia. Using a sample of listed companies, we examine whether the GFC impacted the propensity of auditors to issue going concern modifications and increased audit effort as reflected in audit fees and audit reporting lag. Controlling for client characteristics, we find an increase in the propensity to issue going concern opinions during the period 2008–2009 compared with the period 2005–2007 and that Big N auditors responded to the GFC earlier than non-Big N auditors. In relation to audit effort, we find evidence of increased audit fees during the period 2008–2009 compared with the period 2005–2007. There is, however, no evidence of increased audit reporting lags during the GFC.

OGtree is a web-based tool for constructing genome trees of prokaryotic species based on a measure of combining overlapping-gene content and overlapping-gene order in their whole genomes. The overlapping genes (OGs) are defined as adjacent genes whose coding sequences overlap partially or entirely. In fact, OGs are ubiquitous in microbial genomes and more conserved between species than non-OGs. Based on these properties, it has been suggested that OGs can serve as better phylogenetic characters than non-OGs for reconstructing the evolutionary relationships among microbial genomes. OGtree takes the accession numbers of prokaryotic genomes as its input. It then downloads their complete genomes from the National Centre for Biotechnology Information and identifies OGs in each genome and their orthologous OGs in other genomes. Next, OGtree computes an overlapping-gene distance between each pair of input genomes based on a combination of their OG content and orthologous OG order. Finally, it utilizes distance-based methods of building tree to reconstruct the genome trees of input prokaryotic genomes according to their pairwise OG distance. OGtree is available online at http://bioalgorithm.life.nctu.edu.tw/OGtree/.

A new-type charged particle spectrograph has been proposed and built up. It combines the property of the small magnet which can analyse the particle momentum with that of the semiconductor detector which has a higher energy resolution. As a result, the particle identification and the analysis of energy spectrum can be obtained simultaneously. In this paper, the design and structure of this spectrograph are described, some experimental results of using it in nuclear reaction studies are given, and its applications and characteristics are discussed. This kind of spectrograph is more simple and facile but possesses rather better performances.

The reactions of Be9(d, p0)Be10(0), Be9(d, p1)Be10(3.368 MeV), Be9(d, t0)Be8(0), Be9(d, α0)Li7(0) and Be9(d, α1) Li7 (0.478 MeV) have been studied at deuteron bombarding energies from 0.1 to 2.5 MeV. The angular distributions of these five groups of outgoing particles have been measured respectively between θL = 10°and 155°at eleven bombarding energies of 0.150, 0.220, 0.401, 0.706, 1.005, 1.301, 1.484, 1.750, 2.000, 2.250 and 2.500 MeV. The excitation functions of the Be9 (d,p0) Be10 reaction have been measured at θL = 135° from Ed = 0.1 to 2.5 MeV, at θL = 95° from Ed = 0.1 to 2.2 MeV and at θL = 112.5° from Ed, = 0.5 to 2.5 MeV, respectively. By use of thicker targets (100-300μg/cm2) and at Ed = 1.2 MeV, the absolute cross sections of the Be9(d, p0)Be10 reaction were measured at θL = 135°and 112.5°; the results obtained are: σ(p0)(θL = 135°)= 1.60 mb/st and σ(p0)(θL = 112.5°)=1.55 mb/st. Thus, the behaviours of the cross sections of all these five groups of outgoing particles have been obtained in this energy range. These experimental results are discussed to some extent.