This review covers recent developments in the area of particle engineering via spray drying. The last decade has seen a shift from empirical formulation efforts to an engineering approach based on a better understanding of particle formation in the spray drying process. Microparticles with nanoscale substructures can now be designed and their functionality has contributed significantly to stability and efficacy of the particulate dosage form. The review provides concepts and a theoretical framework for particle design calculations. It reviews experimental research into parameters that influence particle formation. A classification based on dimensionless numbers is presented that can be used to estimate how excipient properties in combination with process parameters influence the morphology of the engineered particles. A wide range of pharmaceutical application examples—low density particles, composite particles, microencapsulation, and glass stabilization—is discussed, with specific emphasis on the underlying particle formation mechanisms and design concepts.

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Pharmaceutical particle engineering via spray drying.

Advanced models of fuel droplet heating and evaporation

Controlled synthesis of nanostructured particles by flame spray pyrolysis

Progress in probability density function methods for turbulent reacting flows

When considering how people are infected and what can be done to prevent the infections, answers from many disciplines are sought: microbiology, epidemiology, medicine, engineering and physics. There are many pathways to infection spread, and among the most significant, from an epidemiological point of view, is airborne transport. Microorganisms can become airborne when droplets are generated during speech, coughing, sneezing, vomiting, or atomisation of faeces during sewage removal. The fate of the droplets is governed by the physical principles of transport, with droplet size being the most important factor affecting their dispersion, deposition on surfaces and determining the survival of microorganisms within the droplets. In addition physical characteristics of the indoor environment as well as the design and operation of building ventilation systems are of critical importance. Do we understand the mechanisms of infection spread and can we quantify the droplet dynamics under various indoor conditions? Unfortunately no, as this aspect of infection spread has attracted surprisingly little scientific interest. However, investigations of numerous cases in which a large number of people were infected show how critical the physics of microorganism spread can be. This paper reviews the state of knowledge regarding mechanisms of droplet spread and solutions available to minimize the spread and prevent infections.

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Droplet fate in indoor environments, or can we prevent the spread of infection?

Preface 1. Introduction 2. Theory of isolated droplet vaporization, heating 3. Multicomponent liquid droplets 4. Droplet arrays and groups 5. Spray equations 6. Computational issues 7. Spray applications 8. Droplet interactions with turbulence and vortical structures 9. Droplet behavior at near critical, transcritical, and supercritical conditions Nomenclature References Appendices Index.

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Chris F. Edwards

Papers

Fluid Dynamics and Transport of Droplets and Sprays