2,662 research outputs found

    Performance of Preload on Cohesionless Soils

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    Common occurrence of loose normally consolidated fine sands and silts extending to considerable depths necessitates the utilization of ground improvement techniques along the coasts of Arabian Peninsula. In the case considered, the soil profile consisted of twenty meter thick compressible sands, and preloading technique was suggested to stabilize the foundation soil. The paper presents the performance of the preloading and the level of soil improvement achieved. The observed settlements and settlement-time behaviour are compared with the values estimated from various methods. The soil parameters back calculated from measured field behaviour are reported

    Seismic Capacity of Reinforced Concrete Interior Flat Plate Connections

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    The demand for modular steel buildings (MSBs) has increased because of the improved quality, fast on-site installation, and lower cost of construction. Steel braced frames are usually utilized to form the lateral load resisting system of MSBs. During earthquakes, the seismic energy is dissipated through yielding of the components of the braced frames, which results in residual drifts. Excessive residual drifts complicate the repair of damaged structures or render them irreparable. Researchers have investigated the use of superelastic shape memory alloys (SMAs) in steel structures to reduce the seismic residual deformations. This study explores the potential of using SMA braces to improve the seismic performance of typical modular steel braced frames. The study utilizes incremental dynamic analysis to judge on the benefits of using such a system. It is observed that utilizing superelastic SMA braces at strategic locations can significantly reduce the inter-storey residual drifts

    Inverse Spin Hall Effect in nanometer-thick YIG/Pt system

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    High quality nanometer-thick (20 nm, 7 nm and 4 nm) epitaxial YIG films have been grown on GGG substrates using pulsed laser deposition. The Gilbert damping coefficient for the 20 nm thick films is 2.3 x 10-4 which is the lowest value reported for sub-micrometric thick films. We demonstrate Inverse spin Hall effect (ISHE) detection of propagating spin waves using Pt. The amplitude and the lineshape of the ISHE voltage correlate well to the increase of the Gilbert damping when decreasing thickness of YIG. Spin Hall effect based loss-compensation experiments have been conducted but no change in the magnetization dynamics could be detected

    Some entanglement features of three-atoms Tavis-Cummings model: Cooperative case

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    In this paper we consider a system of identical three two-level atoms interacting at resonance with a single-mode of the quantized field in a lossless cavity. The initial cavity field is prepared in the coherent state while the atoms are taken initially to be either in the uppermost excited state "∣eee>|eee>" or The GHZ\textmd{GHZ}-state or the W\textmd{W}-state. For this system we investigate different kinds of atomic inversion and entanglement, which arise between the different parts of the system due to the interaction. Also the relationship, between entanglement and some other nonclassical effects in the statistical properties, such as collapses and revivals in the atomic inversion where superharmonic effects appear, is discussed. The QQ-functions for different cases are discussed. Most remarkably it is found that the GHZ\textmd{GHZ}-state is more robust against energy losses, showing almost coherent trapping and Schr\"odinger-cat states can not be produced from such state. Also the entanglement of GHZ\textmd{GHZ}-state is more robust than the W\textmd{W}-state. Another interesting feature found is that the state which has no pairwise entanglement initially will have a much improvement of such pairwise entanglement through the evolution. Sudden death and sudden revival of atoms-pairwise entanglement are produced with the W\textmd{W}-state.Comment: 14 pages, 7 figure

    The Role of Demographic and Clinical Characteristics on Risk of COVID-19 Related Infection and Mortality

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    Since the emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) which causes Covid-19, global health systems have struggled to cope with the rising number of related infections, acute admissions and mortalities. Poorer clinical outcomes have been observed amongst older patients with Covid-19 and males, and in those who are obese or who have darker skin(1) . Additionally, poorer outcomes including increased mortality have been associated with low vitamin D status(2,3) . The current observational study aimed to elucidate the association between patient demographic, anthropometric, clinical and biometric characteristics and Covid-19 disease severity and mortality

    Duration Prediction Models for Construction Projects in Middle East

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    Construction industry is one of the most influential motivators of a national economy. The success of construction projects is indispensable to sustain a robust economy. Completion time is important for construction projects, nevertheless project multifaceted objectives, sophisticated nature, inherent uncertainties, and risks are success impediments and can cause time overrun. Stochastic models and simulation scheduling techniques are developed to predict the risk and uncertainty effects on construction projects’ duration. The objective of this research is to develop models that predict the activity durations based on actual data from similar projects. The study introduces comprehensive statistical regression models using historical data of about 84,000 activities in Egypt, Kuwait, and Saudi Arabia. The activities encompass engineering, procurement and construction (EPC) activities for most disciplines of construction projects. The regression models can be utilized to predict more reliably the activities’ duration
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