Reduction of spurious velocity in finite difference lattice Boltzmann models for liquid - vapor systems

The origin of the spurious interface velocity in finite difference lattice Boltzmann models for liquid - vapor systems is related to the first order upwind scheme used to compute the space derivatives in the evolution equations. A correction force term is introduced to eliminate the spurious velocity. The correction term helps to recover sharp interfaces and sets the phase diagram close to the one derived using the Maxwell construction.Comment: 22 pages, 10 figures (submitted to International Journal of Modern Physics C- Physics and Computers

A lattice Boltzmann study of phase separation in liquid-vapor systems with gravity

Phase separation of a two-dimensional van der Waals fluid subject to a gravitational force is studied by numerical simulations based on lattice Boltzmann methods (LBM) implemented with a finite difference scheme. A growth exponent $\alpha=1$ is measured in the direction of the external force.Comment: To appear in Communications in Computational Physics (CiCP

Investigating the Impact of Social Interactions in Adaptive E-Learning by Learning Behaviour Analysis

Adaptive Educational Hypermedia Systems (AEHSs) allow for personalization of e-learning. Social media tools enable learners to create, publish and share their study, and facilitate interaction and collaboration. The integration of social media tools into AEHS offers novel opportunities for learner engagement and extended user modelling, and thereby fosters so-called Social Personalized Adaptive E-learning Environments (SPAEEs). However, there has been a lack of empirical design and evaluation to elaborate methods for SPAEEs. The goal of the research, therefore, is to investigate 1) the learning behaviour patterns within SPAEEs and the use of these patterns for learner engagement, 2) the evaluation methodologies for SPAEEs, and 3) the design principles for SPAEEs. Topolor4 is an SPAEE that has been under iterative development for achieving our research goals. The first prototype was used as an online learning system for MSc level students in the Department of Computer Science, at the University of Warwick, and usage data was anonymously collected for analysis. This poster focuses on system features and learning behaviour analysis. We first present the methodologies applied in the research, followed by the social and adaptive features that Topolor provides. Then we revisit the analysis of learning behaviours. Finally, we propose the follow-up work based on the evaluation results

To Build Light Gamification upon Social Interactions: Requirement Analysis for the Next Version of Topolor

The introduction of social dimension enables traditional adaptive educational hypermedia systems to provide more versatile personalized services. Topolor has been developed to investigate the impacts of social interaction and feasible engagement strategies in such a system. We have evaluated Topolor’s social features from the perspectives of usefulness and ease of use. We intend to develop the next version of Topolor, starting with enhancing relatively lower rated social features. This paper presents our plan of building light gamification upon the evaluated social interaction features with relatively lower rating

Blowing Off Steam: Virus Inhibition of cGAS DNA Sensing

Detection of viral DNA is essential for eliciting mammalian innate immunity. However, viruses have acquired effective mechanisms for blocking host defense. Indeed, in this issue of Cell Host & Microbe, Wu et al. (2015) discover a herpesviral strategy for inhibiting the prominent host sensor of viral DNA, cGAS

EXPERIMENTAL RESEARCH ON DETERMINATION OF DEFORMATIONS IN THE CUTTING PROCESS IN WET SANDY SOILS

The active parts of tillage equipment must be checked for wear resistance, under different conditions working with the soil, so that the average life span should be determined wear resistance, to ensure timely changes of parts. Research in the field has shown that there are at least two main forces acting on the active parts: impact and friction, the action of these forces causes wear. In order to test the tillage knives in laboratory conditions, was used a stand made by INMA Bucharest. With the help of this stand, the deformations in the cutting process were determined in different working conditions: at a certain working speed and at a certain humidity of the sandy soil

Social E-Learning in Topolor: a Case Study

Social e-learning is a process through which learners achieve their learning goals via social interactions with each other by sharing knowledge, skills, abilities and educational materials. Adaptive e-learning enables adaptation and personalization of the learning process, based on learner needs, knowledge, preferences and other characteristics. In this paper, we present a case study that analyzes the social interaction features of a social personalized adaptive e-learning system developed at the University of Warwick, called Topolor. We discuss the results of a quantitative case study that evaluates the perceived usefulness and usability. The results demonstrate a generally high level of learner satisfaction with their learning experience. We extend the discussion of the results to explore future research directions and suggest further improvements for the studied social personalized adaptive e-learning system

Improving Health Mention Classification Through Emphasising Literal Meanings: A Study Towards Diversity and Generalisation for Public Health Surveillance

People often use disease or symptom terms on social media and online forums in ways other than to describe their health. Thus the NLP health mention classification (HMC) task aims to identify posts where users are discussing health conditions literally, not figuratively. Existing computational research typically only studies health mentions within well-represented groups in developed nations. Developing countries with limited health surveillance abilities fail to benefit from such data to manage public health crises. To advance the HMC research and benefit more diverse populations, we present the Nairaland health mention dataset (NHMD), a new dataset collected from a dedicated web forum for Nigerians. NHMD consists of 7,763 manually labelled posts extracted based on four prevalent diseases (HIV/AIDS, Malaria, Stroke and Tuberculosis) in Nigeria. With NHMD, we conduct extensive experiments using current state-of-the-art models for HMC and identify that, compared to existing public datasets, NHMD contains out-of-distribution examples. Hence, it is well suited for domain adaptation studies. The introduction of the NHMD dataset imposes better diversity coverage of vulnerable populations and generalisation for HMC tasks in a global public health surveillance setting. Additionally, we present a novel multi-task learning approach for HMC tasks by combining literal word meaning prediction as an auxiliary task. Experimental results demonstrate that the proposed approach outperforms state-of-the-art methods statistically significantly (p < 0.01, Wilcoxon test) in terms of F1 score over the state-of-the-art and shows that our new dataset poses a strong challenge to the existing HMC methods

Creep-Fatigue Crack Growth in Power Plant Components

In components operating at high temperature, the presence of defect, that may derive from manufacturing process or operating under critical conditions, could raise to creep-fatigue crack growth even at low loading conditions. Creep- fatigue experimental tests have been performed on P91 material, at 600 °C according to ASTM E2760-10 standard, with focus on the effects of the initial nominal stress intensity factor range, ranging between 16 and 22 MPa m 0.5, and the hold time, ranging between 0.1 and 10 hours. The results will be presented in the paper, together with their application for residual life prediction of a power plant cracked pipe, as case study