Browsing by Subject "dust"

Now showing 1 - 2 of 2
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    Estimating aerodynamic roughness over complex surface terrain
    (2013) Nield, Joanna M; King, James; Wiggs, Giles F S; Leyland, Julian; Bryant, Robert G; Chiverrell, Richard C; Darby, Stephen E; Eckardt, Frank D; Thomas, David S G; Vircavs, Larisa H; Washington, Richard
    Surface roughness plays a key role in determining aerodynamic roughness length (zo) and shear velocity, both of which are fundamental for determining wind erosion threshold and potential. While Zocan be quantified from wind measurements, large proportions of wind erosion prone surfaces remain too remote for this to be a viable approach. Alternative approaches therefore seek to relate Zoto morphological roughness metrics. However, dust-emitting landscapes typically consist of complex small-scale surface roughness patterns and few metrics exist for these surfaces which can be used to predict Zofor modeling wind erosion potential. In this study terrestrial laser scanning was used to characterize the roughness of typical dust-emitting surfaces (playa and sandar) where element protrusion heights ranged from 1 to 199 mm, over which vertical wind velocity profiles were collected to enable estimation of zo. Our data suggest that, although a reasonable relationship (R2> 0.79) is apparent between 3-D roughness density and Zo, the spacing of morphological elements is far less powerful in explaining variations in Zothan metrics based on surface roughness height (R2 > 0.92). This finding is in juxtaposition to wind erosion models that assume the spacing of larger-scale isolated roughness elements is most important in determining Zo. Rather, our data show that any metric based on element protrusion height has a higher likelihood of successfully predicting Zo. This finding has important implications for the development of wind erosion and dust emission models that seek to predict the efficiency of aeolian processes in remote terrestrial and planetary environments.
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    Open Access
    The Invisible Story: Underground Health Narratives of Women in Mining
    (2017) Mutendi, Mutsawashe; Macdonald, Helen
    This dissertation may be read on several different levels. At its most accessible, it is a detailed ethnographic description of how ‘women in mining’ negotiate the daily terrain of caregiving and being exposed to highly contagious and resistant diseases that are associated with mining, which could potentially adversely affect their day-to-day lives, wellbeing and family relations. At its most analytical, it utilises Nixon’s concept of ‘slow violence’ by carefully charting the challenges that a female mineworker faces; having to provide for her family even in the most difficult situations, and sometimes at the expense of her own health. Hence, ‘women in mining’ are situated in a web of connections that exist between working underground and being caregivers in their homes; while at risk of transmitting tuberculosis (TB) and acquiring reproductive health related problems. This dissertation illustrates the tactics and coping strategies that women in mining employ, and argues that they ‘make a plan’ to minimise the negative social consequences of ill health.