Browsing by Subject "dust"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Adaptive Kriging Method for Uncertainty Quantification of the Photoelectron Sheath and Dust Levitation on the Lunar Surface
    (ASME, 2021) Wei, Xinpeng; Zhao, Jianxun; He, Xiaoming; Hu, Zhen; Du, Xiaoping; Han, Daoru; Mechanical and Energy Engineering, School of Engineering and Technology
    This paper presents an adaptive Kriging based method to perform uncertainty quantification (UQ) of the photoelectron sheath and dust levitation on the lunar surface. The objective of this study is to identify the upper and lower bounds of the electric potential and that of dust levitation height, given the intervals of model parameters in the one-dimensional (1D) photoelectron sheath model. To improve the calculation efficiency, we employ the widely used adaptive Kriging method (AKM). A task-oriented learning function and a stopping criterion are developed to train the Kriging model and customize the AKM. Experiment analysis shows that the proposed AKM is both accurate and efficient.
  • Thumbnail Image
    Item
    International Analysis of Sources and Human Health Risk Associated with Trace Metal Contaminants in Residential Indoor Dust
    (ACS, 2021-12) Isley, Cynthia Faye; Fry, Kara L.; Liu, Xiaochi; Filippelli, Gabriel Michael; Entwistle, Jane A.; Martin, Adam P.; Kah, Melanie; Meza-Figueroa, Diana; Shukle, John T.; Jabeen, Khadija; Famuyiwa, Abimbola O.; Wu, Liqin; Sharifi-Soltani, Neda; Doyi, Israel N. Y.; Argyraki, Ariadne; Ho, Kin Fai; Dong, Chenyin; Gunkel-Grillon, Peggy; Aelion, C. Marjorie; Taylor, Mark Patrick; Earth Sciences, School of Science
    People spend increasing amounts of time at home, yet the indoor home environment remains understudied in terms of potential exposure to toxic trace metals. We evaluated trace metal (and metalloid) concentrations (As, Cu, Cr, Mn, Ni, Pb, and Zn) and health risks in indoor dust from homes from 35 countries, along with a suite of potentially contributory residential characteristics. The objective was to determine trace metal source inputs and home environment conditions associated with increasing exposure risk across a range of international communities. For all countries, enrichments compared to global crustal values were Zn > Pb > Cu > As > Cr > Ni; with the greatest health risk from Cr, followed by As > Pb > Mn > Cu > Ni > Zn. Three main indoor dust sources were identified, with a Pb–Zn–As factor related to legacy Pb sources, a Zn–Cu factor reflecting building materials, and a Mn factor indicative of natural soil sources. Increasing home age was associated with greater Pb and As concentrations (5.0 and 0.48 mg/kg per year of home age, respectively), as were peeling paint and garden access. Therefore, these factors form important considerations for the development of evidence-based management strategies to reduce potential risks posed by indoor house dust. Recent findings indicate neurocognitive effects from low concentrations of metal exposures; hence, an understanding of the home exposome is vital.