1,003 research outputs found

    Influence of the curing method on compressive strength and porosity of concrete mixed with sea water, marine sand and fly ash

    Get PDF
    There many archipelagic state such as Japan, Indonesia and other countries. Indonesia consists of thousands of islands where many peoples live in the low land area, the distant and isolated islands that lack of clean water or fresh water and mountain sand or river sand.Transporting the fresh water or clean water and mountain\ud aggregates or river aggregates for concrete production to the low land area, the distant and isolated islands will make the price of concrete work becomes more expensive. In order to overcome the problem of shortage of clean water and fine aggregate in the low land area, the distant island, and saving the fresh water over the world, this research seeks to use sea water and sea sand to produce concrete. In order to overcoming the continuous dumping of waste material, this research also uses semen containing wasted material such as fly ash. This research is a part of ongoing investigation that\ud focuses to study the mix design), mechanical properties (compressive strength-modulus elasticity), porosity, and curing method in order to achieve an optimum correlation between sea water, marine sand, cement, river or mountain coarse\ud aggregate in production of high performance concrete. Furthermore, it is important to conduct research on utilization of sea water, whose percentage is 97% of the total water on the earth, as an effort for improving the technology of saving fresh water

    4D STEM: high efficiency phase contrast imaging using a fast pixelated detector

    Get PDF
    Phase contrast imaging is widely used for imaging beam sensitive and weak phase objects in electron microscopy. In this work we demonstrate the achievement of high efficient phase contrast imaging in STEM using the pnCCD, a fast direct electron pixelated detector, which records the diffraction patterns at every probe position with a speed of 1000 to 4000 frames per second, forming a 4D STEM dataset simultaneously with the incoherent Z-contrast imaging. Ptychographic phase reconstruction has been applied and the obtained complex transmission function reveals the phase of the specimen. The results using GaN and Ti, Nd- doped BiFeO3 show that this imaging mode is especially powerful for imaging light elements in the presence of much heavier elements

    Comparison of breakup models for large space in high pressure pulse sprays

    Get PDF
    Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.Optimization of breakup models for high-pressure pulse sprays in a stationary combustor was investigated by an experimental and numerical study. In the spray experiment, we measured the droplet distribution and spray flux under atmospheric pressure. We also conducted a numerical simulation of spray flow using various breakup models and compared the results with those obtained from our experiments to assess the numerical accuracy of the breakup models and propose a suitable breakup model for large spaces. The breakup of the droplets was calculated using three breakup models. The first two are widely used models—Taylor Analogy Breakup (TAB) model (O’Rourke and Amsden, 1987) and the modified KH–RT model. Besides, we propose a third breakup model that combines the KH and TAB models. The results of the proposed model, the KH–TAB model, are in good agreement with those obtained from our measurements. Hence, we conclude that the KH–TAB model is an appropriate breakup model for large spaces such as in the stationary combustor.dc201

    Impurity effect of Lambda particle on the structure of 18F and 19F_Lambda

    Full text link
    We perform three-body model calculations for a sdsd-shell hypernucleus Λ19^{19}_{\Lambda}F (Λ17O+p+n^{17}_{\Lambda}{\rm O}+p+n) and its core nucleus 18^{18}F (16O+p+n^{16}{\rm O}+p+n), employing a density-dependent contact interaction between the valence proton and neutron. We find that the B(E2)B(E2) value from the first excited state (with spin and parity of Iπ=3+I^\pi=3^+) to the ground state (Iπ=1+I^\pi=1^+) is slightly decreased by the addition of a Λ\Lambda particle, which exhibits the so called shrinkage effect of Λ\Lambda particle. We also show that the excitation energy of the 3+3^+ state is reduced in Λ19^{19}_{\Lambda}F compared to 18^{18}F, as is observed in a pp-shell nucleus 6^{6}Li. We discuss the mechanism of this reduction of the excitation energy, pointing out that it is caused by a different mechanism from that in Λ7^{7}_{\Lambda}Li.Comment: 8 pages, 3 figure

    Structure of excited states of Be-11 studied with Antisymmetrized Molecular Dynamics

    Get PDF
    The structures of the ground and excited states of Be-11 were studied with a microscopic method of antisymmetrized molecular dynamics. The theoretical results reproduce the abnormal parity of the ground state and predict various kinds of excited states. We suggest a new negative-parity band with a well-developed clustering structure which reaches high-spin states. Focusing on a 2α2\alpha clustering structure, we investigated structure of the ground and excited states. We point out that molecular orbits play important roles for the intruder ground state and the low-lying 2ω2\hbar \omega states. The features of the breaking of α\alpha clusters were also studied with the help of data for Gamow-Teller transitions.Comment: 24 pages, 7 figures, to be submitted to Phys.Rev.

    Stationary waves and slowly moving features in the night upper clouds of Venus

    Full text link
    At the cloud top level of Venus (65-70 km altitude) the atmosphere rotates 60 times faster than the underlying surface, a phenomenon known as superrotation. Whereas on Venus's dayside the cloud top motions are well determined and Venus general circulation models predict a mean zonal flow at the upper clouds similar on both day and nightside, the nightside circulation remains poorly studied except for the polar region. Here we report global measurements of the nightside circulation at the upper cloud level. We tracked individual features in thermal emission images at 3.8 and 5.0 μm\mathrm{\mu m} obtained between 2006 and 2008 by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS-M) onboard Venus Express and in 2015 by ground-based measurements with the Medium-Resolution 0.8-5.5 Micron Spectrograph and Imager (SpeX) at the National Aeronautics and Space Administration Infrared Telescope Facility (NASA/IRTF). The zonal motions range from -110 to -60 m s1^{-1}, consistent with those found for the dayside but with larger dispersion. Slow motions (-50 to -20 m s1^{-1}) were also found and remain unexplained. In addition, abundant stationary wave patterns with zonal speeds from -10 to +10 m s1^{-1} dominate the night upper clouds and concentrate over the regions of higher surface elevation.Comment: 15 pages, 4 figures, 6 supplementary figure

    COMPARISON OF SOLUTION ALGORITHM FOR FLOW AROUND A SQUARE CYLINDER

    Get PDF
    ABSTRACT Numerical accuracy, numerical stability and calculation time are all important factors in the computational fluid dynamics. In this study, we compare two solution algorithms, the Simplified Marker and Cell (SMAC) method in the MAC-type methods and the Semi-Implicit Method for Pressure-Linked Equation (SIMPLE) algorithm in the SIMPLE-type algorithms, with respect to flow around a square cylinder in constant density and unsteady-state calculations using a staggered grid to investigate the numerical accuracy, the numerical stability and the computational time. For the flow around a square cylinder, the SMAC and SIMPLE solutions are in excellent agreement at the Strouhal number, drag and lift coefficients. However, SMAC is more unstable than SIMLE with a large Courant number. The computational time of the SMAC is shorter than that of the SIMPLE with a small Courant number

    Second law, entropy production, and reversibility in thermodynamics of information

    Full text link
    We present a pedagogical review of the fundamental concepts in thermodynamics of information, by focusing on the second law of thermodynamics and the entropy production. Especially, we discuss the relationship among thermodynamic reversibility, logical reversibility, and heat emission in the context of the Landauer principle and clarify that these three concepts are fundamentally distinct to each other. We also discuss thermodynamics of measurement and feedback control by Maxwell's demon. We clarify that the demon and the second law are indeed consistent in the measurement and the feedback processes individually, by including the mutual information to the entropy production.Comment: 43 pages, 10 figures. As a chapter of: G. Snider et al. (eds.), "Energy Limits in Computation: A Review of Landauer's Principle, Theory and Experiments
    corecore