Archives

  • 2018-07
  • 2019-04
  • 2019-05
  • 2019-06
  • 2019-07
  • 2019-08
  • 2019-09
  • 2019-10
  • 2019-11
  • 2019-12
  • 2020-01
  • 2020-02
  • 2020-03
  • 2020-04
  • 2020-05
  • 2020-06
  • 2020-07
  • 2020-08
  • 2020-09
  • 2020-10
  • 2020-11
  • 2020-12
  • 2021-01
  • 2021-02
  • 2021-03
  • 2021-04
  • 2021-05
  • 2021-06
  • 2021-07
  • 2021-08
  • 2021-09
  • 2021-10
  • 2021-11
  • 2021-12
  • 2022-01
  • 2022-02
  • 2022-03
  • 2022-04
  • 2022-05
  • 2022-06
  • 2022-07
  • 2022-08
  • 2022-09
  • 2022-10
  • 2022-11
  • 2022-12
  • 2023-01
  • 2023-02
  • 2023-03
  • 2023-04
  • 2023-05
  • 2023-06
  • 2023-08
  • 2023-09
  • 2023-10
  • 2023-11
  • 2023-12
  • 2024-01
  • 2024-02
  • 2024-03
  • Therefore the SPH algorithm in AUTODYN D

    2020-11-30

    Therefore, the SPH algorithm in AUTODYN-3D™ was used to simulate the experiment in Ref. [5] to verify the credibility of the numerical simulation method by results that could be measured accurately. Then the verified numerical simulation method was used to simulate BAD generated by RHA subjected to normal penetration of the typical EFP, in order that the results obtained by theoretical model whose error range was large in experiments could be verified [30]. The types of material, equations of state and constitutive relations in the numerical simulation model were all the same as that in Ref. [5], the main parameters of the simulation had already been introduced in details in Ref. [5], while the main parameters of the experimental setting had already been introduced in details in Ref. [30]. And the credibility of numerical simulation method had also been proved in Ref. [30].
    The time history of the crater radius
    The mass of BAD
    Conclusions This paper draws the following conclusions:
    Funding statement This work was financially supported by the National Natural Science Foundation of China (Grant No. 11372136).
    Introduction The transport phenomenon of radon through GSK621 synthesis is a significant contributor to indoor radon entry (Renken and Rosenberg, 1995; Lively and Goldberg, 1999). The diffusion of radon in dwellings is a process determined by the radon concentration gradient across the building material structure between the radon source and the surrounding air. Radon diffusion and transport through different media is a complex process and is affected by several factors (Tanner, 1980; Singh et al., 1999; Chauhan and Chakarvarti, 2002). For any material medium the porosity, permeability and the diffusion coefficient are the parameters which can quantify their capability to hinder the flow of radon soil gas. An increase in porosity will provide more air space within the material for radon to travel, thus reducing resistance to radon transport. The permeability of material describes ability to act as a barrier to gas movement when a pressure gradient exists across it and is closely related to the porosity of material. The radon diffusion coefficient of a material quantifies the ability of radon gas to move through it when a concentration gradient is the driving force. The radon gas permeability depends on the grain size, the porosity, the water contents and the degree of compaction of the medium (Singh et al., 1999; Chauhan and Chakarvarti, 2002; Culot GSK621 synthesis et al., 1976; Ghosh and Sheikh, 1976). Radon diffusion through material media obeys the equation:where N is the concentration of radon at any time t at a distance X from source, N0 is the concentration of radon at source and λ is the decay constant of radon. If N1 and N2 are the radon concentrations at distances X1 and X2 from source respectively, then using Eq. (1) the effective diffusion coefficient D is given by: Eq. (2) can be used to calculate effective diffusion coefficient of radon through material medium. The diffusion length can be calculated using the eqn:where D is effective diffusion coefficient of radon and λ is decay constant of radon. In the present study, radon diffusion coefficients and diffusion lengths have been calculated using Eqs. (2), (3).
    Experimental The apparatus designed for the study of radon diffusion through ordinary Portland cement mixed with RHA consists of a hollow plastic cylinder of inner diameter 25 cm and length 50 cm deployed vertically (Fig. 1). The uranium ore (activity 20 kBq/kg) was used as radon source covered with latex membrane fixed at the bottom of the cylinder in the cavity. Fourteen open-ended cylindrical diffusion tubes of diameter 1.5 cm and of length 15 and 25 cm were installed in hollow plastic cylinder fixed with radon source. Different mixes of Ordinary Portland Cement (OPC) and RHA (10–50% by weight) were filled in pulverized form in different open-ended diffusion tubes upto the height of 10 cm and 20 cm (Fig. 1). A piece of LR-115 type-II plastic track detector (1 cm × 1 cm) was fixed at the top of each diffusion tube such that sensitive side of the detector always faced the source. The system was left undisturbed for a period of 30 days. The back ground correction was also applied in each case under study. The packing density of each sample was also calculated by taking mass over volume ratio. At the end of the exposure time, the detectors were removed, chemically etched in 2.5 N NaOH solution at 60 °C for 90 min and thoroughly washed and dried. The alpha tracks were counted using an optical Olympus microscope with CCTV camera and a monitor, at 600 X. One hundred graticular fields of the detectors in each case were scanned to reduce statistical errors. The values of diffusion coefficients for different media were calculated using Eq. (2) and the diffusion lengths using Eq. (3).