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During solid surface impact, a falling drop's energy is transformed into oscillations of its liquid/gas interface. We consider drop deposition during oblique impact in the capillary-ballistic regime characterized by high Reynolds number and moderate Weber number. We treat this as an inverse problem showing that post-impact observations of the frequency spectrum and modal partition of energy allow one to determine a drop's pre-impact characteristics and wetting properties. Our analysis is useful for quantifying contact-line dissipation during inertial spreading and can be used as a diagnostic technique for determining substrate wetting properties.
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Winding down the Chicxulub impact: The transition between impact and normal marine sedimentation near ground zero
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Abstract Porosity and its distribution in impact craters has an important effect on the petrophysical properties of impactites: seismic wave speeds and reflectivity, rock permeability, strength, and density. These properties are important for the identification of potential craters and the understanding of the process and consequences of cratering. The Chicxulub impact structure, recently drilled by the joint International Ocean Discovery Program and International Continental scientific Drilling Program Expedition 364, provides a unique opportunity to compare direct observations of impactites with geophysical observations and models. Here, we combine small‐scale petrographic and petrophysical measurements with larger‐scale geophysical measurements and numerical simulations of the Chicxulub impact structure. Our aim is to assess the cause of unusually high porosities within the Chicxulub peak ring and the capability of numerical impact simulations to predict the gravity signature and the distribution and texture of porosity within craters. We show that high porosities within the Chicxulub peak ring are primarily caused by shock‐induced microfracturing. These fractures have preferred orientations, which can be predicted by considering the orientations of principal stresses during shock, and subsequent deformation during peak ring formation. Our results demonstrate that numerical impact simulations, implementing the Dynamic Collapse Model of peak ring formation, can accurately predict the distribution and orientation of impact‐induced microfractures in large craters, which plays an important role in the geophysical signature of impact structures.more » « less
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null (Ed.)To address the need for more structured, diverse, inclusive, equitable, holistic, and ongoing career planning, Individual Development Plans (IDPs) are used widely by academic institutions. Although IDPs have an enormous capacity to contribute to a wide scope of student outcomes including equitable training, mentorship, wellness, and career planning, assessment is complicated by the different IDP ideologies, frameworks, and tools that exist, as well as the different ways IDP creation process is facilitated. The goal of the NSF-funded Impact Indicators and Instruments for Individual Development Plans (I3IDP) project is to develop instruments to measure the outcomes and impact of IDPs on the development of graduate students in STEM. The development of these assessment instruments will facilitate the generation of comparable data within and across institutions to enhance the understanding of best practices in IDP use for PhD career planning. Of particular note is how IDPs may help lower the career and training barriers that exist for diverse and underrepresented groups. Partners behind this NSF funded project include GCC and creators from well-known IDP tools (myIDP.org, ChemIDP.org, ImaginePhD). In this interactive session we will present the indicators and outcomes of the IDP process as determined from stakeholder interviews and literature review, give participants a preview of the survey instruments, and discuss how IDP intervention can be used to provide more equitable training to graduate students and postdocs across multiple identity differences and intersectionality.more » « less
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1016/j.margeo.2020.106368
