3,921 research outputs found
What were Cottons for in the Early Industrial Revolution
Original paper can be found at: http://www.lse.ac.uk/collections/economicHistory/GEHN/GEHNPaduaConferencePapers.ht
High-throughput in-situ characterization and modelling of precipitation kinetics in compositionally graded alloys
The development of new engineering alloy chemistries is a time consuming and
iterative process. A necessary step is characterization of the
nano/microstructure to provide a link between the processing and properties of
each alloy chemistry considered. One approach to accelerate the identification
of optimal chemistries is to use samples containing a gradient in composition,
ie. combinatorial samples, and to investigate many different chemistries at the
same time. However, for engineering alloys, the final properties depend not
only on chemistry but also on the path of microstructure development which
necessitates characterization of microstructure evolution for each chemistry.
In this contribution we demonstrate an approach that allows for the in-situ,
nanoscale characterization of the precipitate structures in alloys, as a
function of aging time, in combinatorial samples containing a composition
gradient. The approach uses small angle x-ray scattering (SAXS) at a
synchrotron beamline. The Cu-Co system is used for the proof-of-concept and the
combinatorial samples prepared contain a gradient in Co from 0% to 2%. These
samples are aged at temperatures between 450{\textdegree}C and
550{\textdegree}C and the precipitate structures (precipitate size, volume
fraction and number density) all along the composition gradient are
simultaneously monitored as a function of time. This large dataset is used to
test the applicability and robustness of a conventional class model for
precipitation that considers concurrent nucleation, growth and coarsening and
the ability of the model to describe such a large dataset.Comment: Published in Acta Materiali
An assessment of global resources of rocks as suitable raw materials for carbon capture and storage by mineralisation
Carbon capture and storage by mineralisation (CCSM) is a method proposed for capturing CO2 by reacting it with magnesium in ultramafic rocks to form carbonate minerals and silica. Large quantities of magnesium silicate rocks are required for this process and to demonstrate the feasibility, and adequately plan for the development and supply of mineral resources, their locations and quantities must be known. This study attempts to globally define the spatial extent and quantity of resources that could be used for the CCSM processes and to assess, if based on resources, this could be a viable, widely applicable CO2 sequestration process. It has been estimated that around 90 teratonnes of material is available. This is sufficient to capture global CO2 emissions for over 700 years at current levels of output and highlights the enormous resource. Even if only a small part is utilised, it could make a significant impact on CO2 reduction. The majority of the resource is contained within ophiolitic rocks. The study further attempts to split CCSM resources into altered (serpentine-rich rocks) and unaltered (olivine-rich rocks) due to the different processing requirements for these rock types. Carbon capture and storage by mineralisation is likely to be of most use in areas with no access to underground geological CO2 storage or for small operations where underground storage is not practical. This study demonstrates that substantial resources are available and their supply is unlikely to be a constraint
The Importance of Ending Well: A Virtual Last Class Workshop for Course Evaluation and Evolution
The last class session of the academic term represents an excellent opportunity to solicit meaningful feedback from students who have just completed the course. To capitalize on the students’ first-hand knowledge of their own experiences with our course and maximize the impact of the last class for our Canadian graduate-level genetics course, we have used and optimized a workshop first described by Bleicher (2011) as a means of obtaining real-time, in-person course evaluations, and driving course evolution. Presented as an empowering opportunity for student activism, students are asked to contribute collaboratively to improving future iterations of the course. This approach stimulates thoughtful discussions, generates honest and useful feedback, and requires only nominal preparative work on the part of the instructor, whose primary role during the workshop is as a facilitator. In light of the COVID-19 pandemic, we’ve assessed student perceptions of two virtual models for the Last Class Workshop—one using Google Docs, a free web-based word processor, and another using Miro, a collaborative whiteboard platform—to identify whether or not the Last Class Workshop can be effectively translated for a synchronous online learning environment. Student responses to the virtual workshops have been highly positive, and participants overwhelmingly preferred the Miro adaptation. We suggest that this is an effective way to access the expert knowledge of our students to develop innovative adaptations, updates, and evolutionary change at the end of a course, and conclude with a proposal for maintaining this virtual tool after in-person learning resumes
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