scholarly journals Synthesis of Radiative-cooling Si2N2O Particles using Silicon Dioxide Powders Obtained by Hydrothermal Processing of Waste Glass Powders

Author(s):  
Shigeki Yoshida ◽  
Hidetoshi Miyazaki ◽  
Shogo Sugahara ◽  
Yasushi Seike ◽  
Hisao Suzuki ◽  
...  
2013 ◽  
Vol 121 (1410) ◽  
pp. 242-245 ◽  
Author(s):  
Hidetoshi MIYAZAKI ◽  
Shigeki YOSHIDA ◽  
Yosuke SATO ◽  
Hisao SUZUKI ◽  
Toshitaka OTA

2018 ◽  
Vol 7 (4) ◽  
pp. 236
Author(s):  
James H. Haido ◽  
Youkhanna Z. Dinkha ◽  
Badorul H. Abu-Bakar

Manufactured reactive powders, as a silica fume, are usually used in production of high strength concrete with for retrofitting purposes of concrete structures. The efficiency of inert waste glass powder in hybrid concrete fabrication has not been widely investigated, thus further studies are essentially considered in this area. In the present study, hybrid concrete prisms with size of 10x10x30 cm have been made with old ordinary concrete (OC) and new high strength concrete (HSC). High strength of new concrete part of these prisms is achieved via using of waste glass powder, silica fume and mixture of them. The roughness of interfacial surface between old and new parts of hybrid concrete is improved in various manners with utilizing sand blast, holes and grooves. Performance of these elements has been measured in terms of slant shear strength and mode of failure. The results have been shown that there is a relatively similar strength with using retrofitted concrete made with the used powder which includes silica fume, glass powders, and their mixture, the mixture of both powders, namely, silica fume and waste glass powders is regarded a best choice in the present stud. It is demonstrated also that the grooved interface between old and new concretes induces proper strength equivalent to 89% of control concrete prisms strength.


2020 ◽  
Vol 640 ◽  
pp. A53
Author(s):  
L. Löhnert ◽  
S. Krätschmer ◽  
A. G. Peeters

Here, we address the turbulent dynamics of the gravitational instability in accretion disks, retaining both radiative cooling and irradiation. Due to radiative cooling, the disk is unstable for all values of the Toomre parameter, and an accurate estimate of the maximum growth rate is derived analytically. A detailed study of the turbulent spectra shows a rapid decay with an azimuthal wave number stronger than ky−3, whereas the spectrum is more broad in the radial direction and shows a scaling in the range kx−3 to kx−2. The radial component of the radial velocity profile consists of a superposition of shocks of different heights, and is similar to that found in Burgers’ turbulence. Assuming saturation occurs through nonlinear wave steepening leading to shock formation, we developed a mixing-length model in which the typical length scale is related to the average radial distance between shocks. Furthermore, since the numerical simulations show that linear drive is necessary in order to sustain turbulence, we used the growth rate of the most unstable mode to estimate the typical timescale. The mixing-length model that was obtained agrees well with numerical simulations. The model gives an analytic expression for the turbulent viscosity as a function of the Toomre parameter and cooling time. It predicts that relevant values of α = 10−3 can be obtained in disks that have a Toomre parameter as high as Q ≈ 10.


2011 ◽  
Vol 131 (7) ◽  
pp. 235-239 ◽  
Author(s):  
Kaoru Yamashita ◽  
Tomoya Yoshizaki ◽  
Minoru Noda ◽  
Masanori Okuyama

2008 ◽  
Author(s):  
Sergey Stefanovsky ◽  
Alexander Barinov ◽  
Galina Varlakova ◽  
Irene Startseva ◽  
Michael I. Ojovan

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