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Inanimate Debris Generated by Adverse Weather Conditions
Published in Ahmed F. El-Sayed, Foreign Object Debris and Damage in Aviation, 2022
Remove the volcanic ash with a soft brush or vacuum cleaner or a blower. Take care that such removed ash does not cause contamination of other components like probes.
What’s in a NAM(e)?
Published in Vikram M. Mehta, Natural Decadal Climate Variability, 2020
Impacts of volcanic eruptions on the Earth’s climate have been studied for many decades. Long-lived temperature and rainfall anomalies in the past have been attributed to large volcanic eruptions in both low and high latitudes. Sulfur dioxide and ash from eruptions are known to influence the Earth’s radiation balance and thereby the coupled ocean–atmosphere system. Sulfate aerosols formed by sulfur dioxide’s reaction with water in the atmosphere scatter solar short wave radiation, thereby cooling the Earth. These aerosols, if injected into the stratosphere, can warm it by the absorption of the longwave radiation emitted by the Earth-troposphere system, with halogens among the aerosols depleting stratospheric ozone and cooling the poles. Volcanic ash, if injected high enough into the stratosphere, can absorb longwave radiation and warm the stratosphere where it resides before removal due to gravity. Thus, these ejecta from volcanic eruptions can influence zonal and meridional temperature gradients in the stratosphere, which can change stratospheric winds and can influence tropospheric winds and temperatures. The explosivity, duration, and composition of materials ejected from a volcanic eruption can determine the strength and duration of the eruption’s effects on climate. Long duration effects can also influence ocean–atmosphere interactions with consequent effects on multiyear to decadal and longer timescale climate variability.
Evolution of Structures
Published in Stuart R. Stock, MicroComputed Tomography, 2019
The pore structure of cement-based materials seriously affects resistance to environmental attack as well as mechanical properties. Often pozzolans (fine natural volcanic ash, fly ash from power generation, diatomaceous earth, etc.) are added to cement to produce a fine-structured composite. A study of the pore structure of Portland cement composites with pozzolan (neat cement vs 25 wt.% fly ash vs 10 wt.% metakaolin) found mean pore size and maximum pore diameters decreased for the composites compared to the simple cement (Rattanasak and Kendall 2005). Chloride permeability is one cement durability issue, and microCT-measured pore structure of a reference concrete and of fly ash, silica fume, and slag-modified concretes were compared with results of a rapid chloride permeability test (Lu, Landis et al. 2006). With 4-µm voxels, little pore connectivity over distances of 100–200 µm was documented for any of the four conditions; with 1-µm voxels the reference concrete showed deep pore penetration while the modified concretes showed clear gaps in connected pore spaces. The somewhat limited data showed chloride permeability correlated clearly with disconnected pore distance (Lu, Landis et al. 2006).
Preparation and rheological performance analysis of volcanic ash and metakaolin based geopolymer grouting materials
Published in Road Materials and Pavement Design, 2023
Zhanning Yang, Siqi Zhou, Feng Li, Rongrong Zhang, Xingyi Zhu
Volcanic ash (VA) is formed by the cooling of magma after a volcanic eruption and is distributed widely throughout the world. VA not only takes up much land impacting human productive activities but also is a serious pollution source that threatens human health and the environment (Belviso et al., 2021). The proper utilisation of VA has increasingly become a vital issue of concern. Numerous studies have shown that the main chemical composition of VA is SiO2 and Al2O3 (Metekong et al., 2021; Lemougna et al., 2020), offering the possibility of preparing geopolymer. The presence of large deposits could have significant economic benefits. However, the practical application of VA as a grouting material is limited (Djobo et al., 2016; Zhou et al., 2020a). With high Si/Al ratios, low CaO, and low amorphous phase content, VA is less reactive than other mineral precursors, resulting in the high shrinkage and low compressive strength of VA-based geopolymer at ambient temperatures.
Research agenda for the Russian Far East and utilization of multi-platform comprehensive environmental observations
Published in International Journal of Digital Earth, 2021
Tuukka Petäjä, Kirill S. Ganzei, Hanna K. Lappalainen, Ksenia Tabakova, Risto Makkonen, Jouni Räisänen, Sergey Chalov, Markku Kulmala, Sergej Zilitinkevich, Petr Ya Baklanov, Renat B. Shakirov, Natalia V. Mishina, Evgeny G. Egidarev, Igor I. Kondrat’ev
The volume of volcanic ash delivered to atmosphere has a pronounced impact on landscapes and river systems being the main stressor of the environmental processes in the region. These have various impacts on pollution rates and ecosystem production. Mercury and spheroidal carbonaceous particles (an unambiguous indicator of fossil fuel combustion) concentrations are typically low but clearly detectable indicating that both regional and global pollution sources are observed in the lakes (Jones et al. 2015). More recently, the geochemical signals in river system to volcano eruption (Kuksina and Alekseevskii 2018) emphasize the importance of comprehensive environmental observation. Overall, there are no established processes to support any kind of regular monitoring observations in the region (Jones and Solomina 2015).
Planning to adapt: identifying key decision drivers in disaster response planning
Published in Civil Engineering and Environmental Systems, 2021
Charlotte O. Brown, Josh L. Hayes, Mark W. Milke
Volcanic ash also causes disruption to critical infrastructure systems (Wilson et al. 2012). For example, ashfall on road networks can reduce surface traction and visibility causing increases in accident rates (Blake, Wilson, and Gomez 2016). There have been examples where this disruption has had flow-on effects to other critical infrastructure systems, for example when maintenance workers are unable to access critical infrastructure sites such as hydroelectric power stations. Thus, decision-makers will need to consider whether they are willing to conduct multiple clean-up responses or whether they are willing to tolerate the negative effects of the ash (infrastructure disruption, health issues, socio-economic impacts) to minimise clean-up costs. Thus, the decision on whether to activate a coordinated clean-up response will hinge on the confluence between: effects on infrastructure and buildings,periodicity and duration of effects on society,real or perceived effects on public health, andfinancial context of the area affected.