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Elvira K.S.,ETH Zurich | Wootton R.C.R.,ETH Zurich | Reis N.M.,Loughborough University | Mackley M.R.,New Museums Site | DeMello A.J.,ETH Zurich
ACS Sustainable Chemistry and Engineering | Year: 2013

Singlet oxygen, a reactive oxygen species, has been a basic synthetic tool in the laboratory for many years. It can be generated either through a chemical process or most commonly via a photochemical process mediated by a sensitizing dye. The relative paucity of singlet oxygen employment in fine chemical industrial settings can be attributed to many factors, not least the requirement for excessive quantities of oxygenated organic solvents and the dangers that these represent. Microcapillary films (MCFs) are comprised of multiple parallel channels embedded in a plastic film. In this study, MCFs are employed as flow reactor systems for the singlet oxygen mediated synthesis of ascaridole. No gaseous oxygen is supplied directly to the reaction, rather mass transport occurs exclusively through the reactor walls. The rate of production of ascaridole was found to be strongly dependent on the partial pressure of oxygen present within the reaction system. This methodology significantly simplifies reactor design, allows for increased safety of operation, and provides for space-time yields over 20 times larger than the corresponding bulk synthesis. © 2013 American Chemical Society. Source


McNally D.J.,New Museums Site | McNally D.J.,Protein Sciences Corporation | Darling D.,Kings College London | Farzaneh F.,Kings College London | And 2 more authors.
Journal of Chromatography A | Year: 2014

The ability of an anion exchange membrane to purify a γ-retrovirus was assessed and optimised with respect to different loading and wash buffers. Recoveries of infectious virus greater than 50% were consistently obtained, while specific titre was increased up to one thousand fold when compared to the material loaded. Specific proteins removed and retained by this optimised process were identified by mass spectrometry. It was possible to successfully bind and elute the equivalent of 1.27×108Ifu/ml of ion exchange membrane. This could then be highly concentrated, with infectious virus concentrated to a maximum of 420-fold compared to the load. © 2014 The Authors. Source


Wilson D.I.,New Museums Site | Rough S.L.,New Museums Site
Canadian Journal of Chemical Engineering | Year: 2012

The multi-phase nature of granular pastes, coupled with their non-Newtonian rheology and inherent inhomogeneity, makes characterisation and prediction of flow behaviour challenging. We focus on 'stiff' pastes which can maintain their shape after extrusion. We describe how the approach presented by Benbow and Bridgwater can be used to predict the deformation and flow behaviour of such materials. Illustrations are drawn from industrial pastes and applications studied in our group. Its basis in viscoplasticity and pure plasticity is discussed. Problems associated with 'stiff' pastes are highlighted. Finally, a roadmap is presented summarising how we think the progress of paste understanding needs to be developed. © 2011 Canadian Society for Chemical Engineering. Source


Wang S.,New Museums Site | Wilson D.I.,New Museums Site
Industrial and Engineering Chemistry Research | Year: 2015

A benchtop fluid-dynamic gauging device to study the swelling or shrinking of soft solid layers immersed in a liquid environment in situ and in real time is demonstrated. A particular feature is that the volume of liquid is isolated, hence the name zero-net-discharge fluid-dynamic gauging (ZFDG), which renders ZFDG suitable for aseptic operation. For the 1.78 mm nozzle diameter used here, calibration tests gave a resolution of ±5 ∼m and an uncertainty of ±10 ∼m. Computational fluid dynamics simulations indicated that the shear stress imposed on a layer being gauged differed between the successive suction and ejection stages in ZFDG. The swelling of poly(vinyl acetate) (PVA) layers (about 1 mm dry thickness) and gelatin films (50-80 ∼m dry thickness) in aqueous solutions is reported as a demonstration of ZFDG application. There was good agreement with more cumbersome gravimetric methods. The gelatin swelled noticeably faster at high pH, above the pKa values of proline and hydroxyproline. Fitting the gelatin swelling data to a power law model indicated sub-Fickian behavior with a diffusion index that increased with the pH. © 2015 American Chemical Society. Source


Magens O.M.,New Museums Site | Ishiyama E.M.,IHS Downstream Research | Wilson D.I.,New Museums Site
Applied Thermal Engineering | Year: 2016

Fouling is a chronic problem in many heat transfer systems and leads to regular cleaning of heat exchangers. Antifouling coatings are one mitigation option: The financial attractiveness of installing a coated exchanger depends on trade-offs between capital and operating costs over the lifetime of the unit. Such considerations effectively set bounds on the price of coatings, bounded by manufacturing costs and the maximum saving that can be achieved from fouling mitigation, in a 'value pricing' calculation. The 'value pricing' concept is considered here, for the first time, for heat exchangers subject to asymptotic fouling. An explicit solution to the cleaning scheduling optimisation problem is presented for the case of equal heat capacity flow rates in a counter-current single phase exchanger. A case study is used to illustrate the concepts and key learnings. A sensitivity analysis identifies scenarios where the use of antifouling coatings may be attractive, and also where there is no financial benefit in cleaning a fouled exchanger. © 2016 Elsevier Ltd. All rights reserved. Source

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