1,776 research outputs found
Controlled release of drug encapsulated as a solid core: theoretical model and sensitivity analysis
No full textCFD modelling of condensers for freeze-drying processes
No full textThe aim of the present research is the development of a computational tool for investigating condensation processes and equipments with particular attention on freeze-dryers. These condensers in fact are usually operated at very low pressures, making it difficult to experimentally acquire quantitative knowledge of all the variables involved. Mathematical modelling and CFD (Computational Fluid Dynamics) simulations are here used to achieve a better comprehension of the flow dynamics and of the process of ice condensation and deposition in the condenser, in order to evaluate condenser efficiency and gain deeper insights on the process to be used for the improvement of its design. Both a complete freeze-drying apparatus of laboratory-scale and an industrial-scale condenser have been investigated in this work, modelling the process of water vapour deposition. Different operating conditions have been considered and the influence exerted by the inert gas as well as other parameters have been investigate
Modelling and experimental investigation of radiation effects in a freeze-drying process
No full textDr. Miriam McCormick – Faculty Author Interview
No full textDr. Miriam McCormick, Associate Professor of Philosophy and Philosophy, Politics, Economics and Law, discusses her new book, Believing Against the Evidence: Agency and the Ethics of Belief published recently by Routledge. In this book, Dr. McCormick argues that the standards used to evaluate beliefs are not isolated from other evaluative domains. The ultimate criteria for assessing beliefs are the same as those for assessing action because beliefs and actions are both products of agency
Simulation of coalescence, break-up and mass transfer in a gas-liquid stirred tank with CQMOM
No full textIn this work oxygen mass transfer in a turbulent air-water stirred tank is investigated. A multivariate population balance model is coupled with the Eulerian multi-fluid approach to describe the spatial and temporal evolution of the bubble size and composition distributions. For the numerical solution of the population balance model the conditional quadrature method of moments is employed and implemented through user-defined scalars and functions in the computational fluid dynamics code ANSYS/Fluent 12. The approach is validated by comparing model predictions with experiments (from the literature) conducted in an air-water stirred tank equipped with a Rushton turbine and a porous sparger. First predictions are compared with the experimentally measured mean Sauter diameter. The comparison highlights that the modelling approach is capable of predicting the main feature of the system. Then oxygen mass transfer is simulated and predictions for the oxygen accumulation in water are validated against experiments. Also for this comparison good agreement is foun
APPLICATION OF THE CONDITIONAL QUADRATURE METHOD OF MOMENTS FOR THE SIMULATION OF COALESCENCE, BREAKUP AND MASS TRANSFER IN GAS-LIQUID STIRRED TANKS
No full textMass transfer has been investigated in a gas-liquid stirred reactor by considering the absorption of oxygen in the liquid phase (water). A multivariate population balance model (PBM), coupled with an Eulerian multi-fluid approach, has been employed to describe the spatial and temporal evolution of the bubbles size and composition distributions. The PBM has been solved by adopting the Conditional Quadrature Method of Moments (CQMOM), that has been implemented through user-defined functions (UDF) and scalars (UDS) in the commercial Computational Fluid Dynamics code Ansys Fluent 12. Model predictions were compared with experimental data of bubble size distributions and then with oxygen accumulation in the liquid phase. The simulation results show that, although coalescence and breakup tend to homogenize bubble composition, a multivariate PBM is necessary to properly describe mass transfer. In fact, due to the fact that smaller bubbles, generally located in regions characterized by high turbulent dissipation rates, exchange mass with a much faster rate than bigger bubbles, both bubble size and bubble composition should be included as internal coordinate
[Rezension zu:] Miriam Havemann: The Subject Rising Against its Author
No full textRezension zu Miriam Havemann: The Subject Rising Against its Author. A Poetics of Rebellion in Bryan Stanley Johnson's Oeuvre. Hildesheim/Zürich/New York (Georg Olms Verlag) 2011 (= ECHO - Literaturwissenschaft im interdisziplinären Dialog, Bd. 13). 427 S.
Mit der Publikation ihrer in der Bochumer Komparatistik eingereichten Dissertation widmet sich Miriam Havemann einem bis vor wenigen Jahren fast in Vergessenheit geratenen britischen Schriftsteller der 1960er und 1970er Jahre, dessen Arbeiten erst mit dem Erscheinen von Jonathan Coes Biographie 'Like a Fiery Elephant: The Story of B.S. Johnson' (2004) und der Wiederauflage vieler seiner Romane neue Beachtung fanden
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