Modeling the effects of high strain rate loading on RC columns using Arbitrary Lagrangian Eulerian (ALE) technique

In recent years, many studies have been conducted by governmental and nongovernmental organizations across the world in an attempt to better understand the effect of explosive loads on buildings in order to better design against specific threats. This study is intended to contribute to increase the knowledge about how explosions affect reinforced concrete (RC) columns. In this study, a nonlinear model is developed to study the blast response of RC columns subjected to explosive loads. Numerical modeling of RC column under explosive load is presented using advanced finite element code LS DYNA. The obtained numerical model is validated with the experimental test and the results are in substantial agreement with the experimental data. ALE method for blast analysis is presented in the current research. The effects of scaled distance on the damage profile of RC columns are investigated. The results demonstrate that the level of damage increased with describing the scaled distance. Also the results shown duration for the blast loading, and hence the impulse, varies with charge masses at the specified scaled distance. Higher magnitude charge masses produced longer blast loading durations than lower magnitude charge masses. This means that at the same scaled distance, a charge mass of higher magnitude produced a higher impulse than the lower magnitude charge mass. The findings of this research represent the scaled distance is an important parameter that should be taken into account when analyzing the behavior of RC columns under explosive effects. The data collected from this research are being used to improve the knowledge of how structures will respond to a blast event, and improve finite element models for predicting the blast performance of concrete structures.Peer Reviewe

Frequency-Doubling of Femtosecond Pulses in “Thick” Nonlinear Crystals With Different Temporal and Spatial Walk-Off Parameters

We present a comparative study on frequency-doubling characteristics of femtosecond laser pulses in thick nonlinear crystals with different temporal and spatial walk-off parameters. Using single-pass second harmonic generation (SHG) of 260 fs pulses at 1064 nm from a high-average-power femtosecond Yb-fiber laser in 5-mm-long crystals of β-BaB2O4 (BBO) and BiB3O6 (BIBO), we find that for comparable values of temporal and spatial walk-off parameters in each crystal, the optimum focusing condition for SHG is more strongly influenced by spatial walk-off than temporal walk-off. It is also observed that under such conditions, the Boyd and Kleinman theory commonly used to define the optimum focusing condition for frequency-doubling of cw and long-pulse lasers is also valid for SHG of ultrafast lasers. We also investigate the effect of focusing on the spectral, temporal, and spatial characteristics of the second harmonic (SH) radiation, as well as angular acceptance bandwidth for the SHG process, under different temporal and spatial walk-off conditions in the two crystalsPeer ReviewedPostprint (author's final draft

Clinical expression of plakophilin-2 mutations in familial arrhythmogenic right ventricular cardiomyopathy

Background - Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiac disorder characterized by loss of cardiomyocytes and their replacement by adipose and fibrous tissue. It is considered a disease of cell adhesion because mutations in desmosomal genes, desmoplakin and plakoglobin, have been implicated in the pathogenesis of ARVC. In a recent report, mutations in plakophilin-2, a gene highly expressed in cardiac desmosomes, have been shown to cause ARVC.Methods and Results - We investigated 100 white patients with ARVC for mutations in plakophilin-2. Nine different mutations were identified by direct sequencing in 11 cases. Five of these mutations are novel (A733fsX740, L586fsX658, V570fsX576, R413X, and P533fsX561) and predicted to cause a premature truncation of the plakophilin-2 protein. Family studies showed incomplete disease expression in mutation carriers and identified a number of individuals who would be misdiagnosed with the existing International Task Force and modified diagnostic criteria for ARVC.Conclusions - In this study, we provide new evidence that mutations in the desmosomal plakophilin-2 gene can cause ARVC. A systematic clinical evaluation of mutation carriers within families demonstrated variable phenotypic expression, even among individuals with the same mutation, and highlighted the need for a more accurate set of diagnostic criteria for ARVC

Simulation of the spreading of a gas-propelled micro-droplet upon impact on a dry surface using a lattice-Boltzmann approach

Spray cooling is one of the most promising methods of cooling high heat flux electronics. Depending on the type of the nozzle, spray cooling can be categorized as single phase or two phase. In the latter, which is known to be more effective, a secondary gas is used to further pressurize the liquid and form smaller droplets at higher velocities. The gas is also assumed to assist the spreading phase by imposing normal and tangential forces on the droplet free surface which adds to the complicated hydrodynamics of the droplet impact. Moreover, the order of magnitude of droplet size in spray cooling is 10¯⁶m thereby introducing a low Weber and Reynolds numbers impact regime which heretofore has not been well understood. A 3D lattice Boltzmann method was implemented to simulate the impact of a single micro-droplet on a dry surface in both ambient air and under a stagnation gas flow. Two cases were closely compared and correlations were proposed for the instantaneous spreading diameter. Contrary to recent findings at higher impact We and Re, it was found that stagnation flow only significantly affects the spreading phase for Ca*⩾0.35 but has little influence on the receding physics

The poetic theory as expounded in Kitab Minhaj al-Bulagha by Hazim al Qartajanni.

The aim of this research is to analyse the philosophical and aesthetic principles of Hazim al-Qartajanni's poetic theory, as set down in his Minhaj al-Bulagha' wa-Siraj al-Udaba. It is our intent, in addition, to reveal the sources for his theory in Graeco-Arabic and Islamic-Arabic sources as well as his contributions to both. The preface defines the subject-matter and the methodology. This is followed by an Introduction which places Hazim in his cultural context by looking at his masters and his pupils, and examining not only his works on criticism, but also his influence on the establishment of a school of Arabic rhetoric in the western parts of the Arab world (Andalusia and North Africa) and on the development of Arabic criticism generally. The thesis is then divided into two parts, each of which has two chapters. Part one, on the nature of poetry in respect of both poet and recipient, deals with; 1) the notion of poetry as it is understood, firstly in the fundamental term of muhakat (imitation) and the complementary terms associated with the root khayal (imagination), and secondly in those issues of classical Arabic criticism which are of central importance to that notion such as the issue of natural aptitude tab' and skill san'a; 2) the question of value judgement in art generally and in poetry, where there are three aspects: the psychological, ethical, and aesthetic; and how these are treated in Classical Arabic critical terminology as well as in the work of Hazim, who is shown to dwell most upon the aesthetic value. Part two, on rhythmic and linguistic structures in the qasida, deals with: 1) the nature of poetic measures, harmony, rhythm, and musicality, generally, as well as the part played by rhyme in creating poetic rhythm and the relation of measures and rhymes to the meaning of poetry; 2) the linguistic features of the qasida from individual components to the entire poetic expression of the whole structure of the qasida. Each chapter has four units, of which the first three discuss the main subject of the chapter in relation to Hazim's work and the Greek and Arab traditions of poetics; while the fourth evaluates Hazim's original contribution in the light of his most influential resources, both Arab and Greek. This thesis includes a glossary of some of Hazim's technical terms which have been employed in their original Arabic form as the equivalent English terms fail to illustrate their meaning accurately

Global Environmental Flow Information for the Sustainable Development Goals

Environmental flows (EF) are an important component of Goal 6 (the ‘water goal’) of the Sustainable Development Goals (SDGs). Yet, many countries still do not have well-defined criteria on how to define EF. In this study, we bring together the International Water Management Institute’s (IWMI’s) expertise and previous research in this area to develop a new methodology to quantify EF at a global scale. EF are developed for grids (0.1 degree spatial resolution) for different levels of health (defined as environmental management classes [EMCs]) of river sections. Additionally, EF have been separated into surface water and groundwater components, which also helps in developing sustainable groundwater abstraction (SGWA) limits. An online tool has been developed to calculate EF and SGWA in any area of interest

Civil society and financial markets : what is not happening and why

Why have commercial financial flows – as a major force in contemporary society with a number of significant problematic consequences – attracted relatively little effective public-interest response from civil society? Change-oriented NGOs, labour unions, faith-based organisations and other social movements have mostly remained in the shadows vis-à-vis private financial markets. Impacts from these citizen associations have not gone beyond promoting modest rises in public awareness, certain limited policy shifts, and minor institutional reforms of a few public governance agencies. The reasons for these scant achievements are partly related to capacities and practices in civil society groups, relevant governance agencies, and financial firms. Also important in constraining civil society impacts to reform and transform contemporary financial markets are deeper structural circumstances such as embedded social hierarchies (among countries, classes, etc.), the pivotal role of finance capital in accumulation processes today, and the entrenchment of prevailing neoliberal policy discourses

Temperature-dependent proximity magnetism in Pt

We experimentally demonstrate the existence of magnetic coupling between two ferromagnets separated by a thin Pt layer. The coupling remains ferromagnetic regardless of the Pt thickness, and exhibits a significant dependence on temperature. Therefore, it cannot be explained by the established mechanisms of magnetic coupling across nonmagnetic spacers. We show that the experimental results are consistent with the presence of magnetism induced in Pt in proximity to ferromagnets, in direct analogy to the well-known proximity effects in superconductivity.Comment: 4 pages, 3 figure

Social Alignment Contagion in Online Social Networks

Researchers have already observed social contagion effects in both in-person and online interactions. However, such studies have primarily focused on users’ beliefs, mental states, and interests. In this article, we expand the state of the art by exploring the impact of social contagion on social alignment, i.e., whether the decision to socially align oneself with the general opinion of the users on the social network is contagious to one’s connections on the network or not. The novelty of our work in this article includes: 1) unlike earlier work, this article is among the first to explore the contagiousness of the concept of social alignment on social networks; 2) our work adopts an instrumental variable approach to determine reliable causal relations between observed social contagion effects on the social network; and 3) our work expands beyond the mere presence of contagion in social alignment and also explores the role of population heterogeneity on social alignment contagion. Based on the systematic collection and analysis of data from two large social network platforms, namely, Twitter and Foursquare, we find that a user’s decision to socially align or distance from social topics and sentiments influences the social alignment decisions of their connections on the social network. We further find that such social alignment decisions are significantly impacted by population heterogeneity