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Ecosystems
Published in Earle A. Ripley, E. Robert Redmann, Adèle A. Crowder, Tara C. Ariano, Catherine A. Corrigan, Robert J. Farmer, L. Moira Jackson, Environmental Effects of Mining, 2018
A. Ripley Earle, Robert E. Redmann, Adèle A. Crowder, Tara C. Ariano, Catherine A. Corrigan, Robert J. Farmer, Earle A. Ripley, E. Robert Redmann, Adèle A. Crowder, Tara C. Ariano, Catherine A. Corrigan, Robert J. Farmer, L. Moira Jackson
Mine waste heaps are also susceptible to collapse, often triggered by earthquakes, but also under static conditions, usually because of “liquefaction” resulting from water buildup in the embankments. Some of the factors that may contribute to this sudden flowing of waste materials are poor drainage, high confining pressure, and large and frequent cyclic stresses on the embankment. An additional factor is the nature of the material; the lower the bulk density of the material, the more likely it is that liquefaction will occur.
Bio-Based Phenol Formaldehyde from Lignocellulosic Biomass
Published in Chin Hua Chia, Chin Han Chan, Sabu Thomas, Functional Polymeric Composites, 2017
Rasidi Roslan, Sarani Zakaria, Chin Hua Chia, Umar Adli Amran, Sharifah Nabihah Syed Jaafar
Liquefaction of lignocellulosic biomass, using phenol as liquefying agent, has been intensively studied for several decades.38 The products obtained from the liquefaction process are increasingly important to be used as starting materials for the production of new energy, solvents, fine chemicals, etc.39,40 Most of the biomass liquefaction reactions were carried out using acid catalyst to significantly increase the conversion yield. Liquefaction under alkaline condition indeed gives low biomass residue content; however, they were not effective catalysts to achieve high amount of combined phenol.41
Renewable Resources for Polyurethanes and Polyurethane Composites: A Review
Published in Omari V. Mukbaniani, Marc J. M. Abadie, Tamara N. Tatrishvili, Chemical Engineering of Polymers, 2017
J. T. Haponiuk, A. Hejna, Ł. Piszczyk, J. Datta, K. Formela
Yana et al. [86] investigated cork liquefaction with glycerol and its mixtures with polyethylene glycol. Authors analyzed the influence of the type and concentration of catalyst (acidic or alkaline), reaction time and temperature, cork content and addition of PEG 400 on the yield of process. Higher yields were obtained in case of alkaline catalysis; authors suggest that it was strongly related to the chemical composition of cork. Replacement up to 50 wt. % of glycerol with polyethylene glycol noticeably increased yield under acidic conditions, simultaneously confirming results presented by Zhang et al. [87]. Further optimization of the liquefaction process and should result in increasing the attractiveness of the process for potential applications.
Three elements of liquefaction risk of liquefiable solid bulk cargoes during sea transport: Critical review
Published in Marine Georesources & Geotechnology, 2022
Zihao Zhao, Wanqing Wu, Qinggong Zheng, Xiaoxiang Yu, Shangwu Yu
The cyclic resistivity of sand samples was used to detect the characteristics of soil voids in a saturated sand liquefaction experiment (Mingyuan 2016). The formation and disappearance of pore water channels were observed during the liquefaction process. Macro- and micro-numerical simulations of a biaxial shear test on ideal granular bodies with different densities were carried out based on DEM (Yang and Shuang 2018; Liu, Li, and Wu 2018). The source of strength and the mechanism of plastic deformation were explained by using the loop element to represent the skeleton structure of the sample. The phenomena, mechanism, influencing factors, microscopic characteristics, evaluation methods, and prevention methods of loess liquefaction in China were systematically reviewed (He et al. 2020). The main influencing factors of liquefaction, including effective confining pressure, load frequency, cyclic stress ratio, saturation, and over consolidation ratio, were considered in the article. Liquefaction should be judged by performing tests based on the standard method or other simplified discriminant methods. Steady-state strength theory and static liquefaction theory are newly developed theories for exploring loess liquefaction and dynamics. In sum, external loads are critical to soil liquefaction.
Effect of different parameters on cyclic triaxial response of biopolymer treated soil
Published in European Journal of Environmental and Civil Engineering, 2022
The popularity and the need for sustainable practices in civil engineering are eminent in the present day. Sustainability is to be introduced in both construction practices as well as in the construction materials being used. Soil is an imperative material as far as civil engineering is concerned. But soil may not always be able to resist various loads coming on to it. In many sites, it might be weak and need to be improved or modified to make it resistant to various types of loads. Such a type of soil is loose silty sand. Silty sand might be able to take up loads when it is in a dry or partially saturated condition. But if it gets fully saturated and when subjected to cyclic loading it is vulnerable to a phenomenon called liquefaction that was the cause of major agonies of many past earthquakes. Liquefaction can cause damage to structures, affect the economy and can even cause loss of life (Bao et al., 2016; Hazout et al., 2017; Shivaprakash & Dinesh, 2017). It causes the underground structures to lift up and structures over the ground to sink (Ambraseys & Sarma, 1969). It may also lead to other calamities like landslides, ground subsidence, sand boils and flow landslide failures (Seed, 1968). Hence the silty sand needs to be stabilised to make it liquefaction resistant. But many traditional approaches for liquefaction mitigation make use of unsustainable practices like the use of cement and chemical admixtures, sand compaction piles, lowering the groundwater table, dynamic compaction, cement grouting etc. (Benhelal et al., 2013; Huang & Wen, 2015; Sharma et al., 2021; Smitha & Rangaswamy, 2021b; Wang et al. 2018). These methods may affect the surrounding structures, pollute the groundwater and may make the soil inhabitable to soil microbes and plants (Gallagher & Mitchell, 2000; Khodadadi & Bilsel, 2012). Therefore, it is necessary to explore and promote new energy efficiency practices (DeJong et al., 2010)
Dynamic Properties of Saturated Sand Based on the in situ Liquefaction Test
Published in Journal of Earthquake Engineering, 2021
Soil liquefaction remains one of the most important topics in soil dynamics and geotechnical earthquake engineering. Experimental evidence indicates that factors that increase the cyclic shear stress (τ) required to initiate liquefaction (i.e. relative density, soil fabric, prior seismic straining, stress history, and aging) also increase the shear modulus (G) of the soil. Assuming that these factors influence both τ and G, similarly, their influence on shear strain (γ), which is the ratio of τ/G, is much less. Thus, the pore pressure generation should be more fundamentally related to strains than stress [Dobry et al. 1982; Dobry and Abdoun 2015; Cox et al. 2009]. Consequently, shear strain can more effectively control the pore pressure generation of saturated sand than shear stress, and the relationship between shear strain and pore pressure is less sensitive to factors such as relative density, etc. With the progress of liquefaction investigations, strain-based evaluating methods for liquefaction potential have been emphasized by researchers [e.g. Dobry and Abdoun 2015]. Thus, the current knowledge on soil liquefaction related to strain issue should be investigated and recognized in advance. The dynamic shear modulus (DSM) is the most basic and important parameter to describe soil dynamic properties in earthquake engineering. In Recent years, compared with many achievements on DSM for common soils (such as dry sand, clay, etc.), only a few studies have investigated the DSM for liquefied soil that must be considered the effect of pore pressure increase through different laboratory tests. Therefore, it is important and necessary to further study dynamic responses and properties of saturated sand during liquefaction through more approaches. The new investigations can provide better understandings of liquefaction-related soil behaviors, and prompt the development of the performance-based approach for seismic design and dynamic responses analysis at liquefied site.