28,711 research outputs found
Protein refolding in an oscillatory flow reactor
We demonstrate that an oscillatory flow reactor is a viable reactor for protein refolding via direct dilution. The
mixing characteristics of the oscillatory flow reactor are well described and controllable and, importantly, can be
scaled-up to process scale without a loss of mixing efficiency. This makes the oscillatory flow reactor an attractive
alternative to conventional stirred-tank reactors for process-scale renaturation
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Designing materials for electrochemical carbon dioxide recycling
Electrochemical carbon dioxide recycling provides an attractive approach to synthesizing fuels and chemical feedstocks using renewable energy. On the path to deploying this technology, basic and applied scientific hurdles remain. Integrating catalytic design with mechanistic understanding yields scientific insights and progresses the technology towards industrial relevance. Catalysts must be able to generate valuable carbon-based products with better selectivity, lower overpotentials and improved current densities with extended operation. Here, we describe progress and identify mechanistic questions and performance metrics for catalysts that can enable carbon-neutral renewable energy storage and utilization
A comparison of A-level performance in economics and business studies: how much more difficult is economics?
This paper uses ALIS data to compare academic performance in two subjects often viewed as relatively close substitutes for one another at A-level. The important role of GCSE achievement is confirmed for both subjects. There is evidence of strong gender effects and variation in outcomes across Examination Boards. A counterfactual exercise suggests that if the sample of Business Studies candidates had studied Economics nearly 40% of those who obtained a grade C or better in the former subject would not have done so in the latter. The opposite exercise uggests that 12% more Economics candidates would have achieved a grade C or better if they had taken Business Studies. In order to render a Business Studies A-level grade comparable to an Economics one in terms of relative difficulty, we estimate that a downward adjustment of 1.5 UCAS points should be applied to the former subject. This adjustment is lower than that suggested by correction factors based on conventional subject pair analysis for these two subjects
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A model of economic growth for an open emerging country: empirical evidence for Brazil
Brazil liberalised its trade and finance in the 1990s as a strategy for higher economic growth. However, the countryâs GDP growth has been unstable and low compared to its own performance during the industrialization period. This paper builds a model of economic growth that accounts for the main components of effective demand as well as important specificities of emerging economies to explain the economic dynamics after the liberalising reforms. The model is estimated for the case of Brazil from 1990 to 2014 and the results suggest that this economy became highly dependent on the world economic growth and the evolution of the real exchange rate. The main finding is that Brazil experiences higher economic growth only in favourable world scenarios but the evolution of the real exchange rate in this scenario may stimulate investments that only reinforce the existing productive structure, affecting negatively the long-run economic growth.Carolina Troncoso Baltar is very grateful to âCoordenação de Aperfeiçoamento de Pessoal de NĂvel Superiorâ (CAPES) for financial support
Brazilian Economic Performance Since The Emergence Of The Great Recession: The Effects Of Income Distribution On Consumption
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)After a long period of unstable and low economic activity, Brazil achieved a relatively high economic growth with low inflation from 2004 to 2008, when the world scenario was favourable for the Brazilian trade balance. An incomes policy, focused on real increases in the minimum wage along with a credit boom, led to a decade of high consumption growth rates. High levels of consumption and exports, in turn, induced investment and stimulated manufacturing production, despite the real appreciation of the national currency. However, the Great Recession that emerged after the global financial crisis of 2007/2008 brought challenges to the Brazilian economic performance, with unpleasant consequences for the country's GDP growth. Consumption, investment and exports have decelerated, despite anti-cyclical macroeconomic policies. In this setting, manufacturing production stagnated and GDP growth slowed down substantially, while imports continued rising considerably. The aim of this paper is to provide an explanation to the slowdown of Brazilian growth rates after the Great Recession. The main hypothesis is that consumption was the main source of effective demand in the country since 2003. However, Brazil has not yet been able to sustain manufacturing and economic growth without a more active government policy to stimulate productive investment.63157174Sao Paulo Research Foudation (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)12th International Conference on Developments in Economic Theory and PolicyJUN 25-26, 2015Bilbao, SPAI
Approximate Hermitian-Yang-Mills structures and semistability for Higgs bundles. II: Higgs sheaves and admissible structures
We study the basic properties of Higgs sheaves over compact K\"ahler
manifolds and we establish some results concerning the notion of semistability;
in particular, we show that any extension of semistable Higgs sheaves with
equal slopes is semistable. Then, we use the flattening theorem to construct a
regularization of any torsion-free Higgs sheaf and we show that it is in fact a
Higgs bundle. Using this, we prove that any Hermitian metric on a
regularization of a torsion-free Higgs sheaf induces an admissible structure on
the Higgs sheaf. Finally, using admissible structures we proved some properties
of semistable Higgs sheaves.Comment: 18 pages; some typos correcte
Impact of the reinforcement layout on the load capacity of reinforced concrete half-joints
A reinforced concrete half-joint beam has a complex geometry that includes both a locally disturbed nib region and a full depth section. While this configuration simplifies the design and construction procedures, half joint structures rely on the internal steel reinforcement to transfer force from the nib into the bulk of the beam. When assessing existing reinforced concrete half-joints, engineers can be confronted with internal reinforcement layouts that do not correspond to the as-designed drawings and/or do not comply with current design practice. Bars may be missing or the location, percentage and spacing of the steel reinforcing bars may be non-compliant.
To provide a better understanding of the contribution of the internal steel reinforcing bars found in a typical half joint detail, an experimental test program on full-scale half-joint beams was undertaken. Four different scenarios were tested to identify the impact of specific reinforcing bars. A reference specimen was designed in accordance with existing practice. The reference beam, and beams with either missing diagonal reinforcement, missing horizontal reinforcement or a reduced amount of shear reinforcement were tested.
All the beams exhibited nib failures with the exception of the beam where the shear reinforcement was reduced. In this case, the failure mode changed from a nib failure to a full-depth failure. The results indicated that if certain bars are missing the overall load bearing capacity of a half-joint could be approximately 40% lower than that of a properly designed detail, but that a redistribution of forces was noted.Engineering and Physical Sciences Research Council through the Project âReinforced concrete half-joint structures: Structural integrity implications of reinforcement detailing and deteriorationâ [Grant no. EP/K016148/1
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Strut-and-tie models for deteriorated reinforced concrete half-joints
A reinforced concrete half-joint bridge consists of suspended span dapped-end beams or a full-width deck supported on the nibs of abutments or adjacent beams. The design of their disturbed regions is traditionally performed by means of strut-and-tie modelling. The design provisions found in standards and codes can be used for the assessment of existing structures with minor adjustments. However, current documents provide limited guidance on the incorporation of deterioration aspects such as corrosion, insufficient anchorage lengths, and crack formation.
Experiments performed on 12 half-joint beams demonstrated the effects of single defects, but synergistic effects were also found to exist and might lead to much higher reductions than expected from the sum of individual defects. These results were compared to different strut-and-tie models (STMs) and the application of STMs to achieve the highest lower bound estimate of the load carrying capacity is discussed.
For the beams studied in the current work, the predictions based on codes and standards, combined with appropriate methods to incorporate deterioration effects, led to safe load bearing capacity estimates. However, the developed STMs seem to be, in some instances, unable to pick up alternative load paths that develop as soon as the capacity of a certain tie is reached. Hence the actual capacities might be higher than what is obtained from the STM calculations
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