E. Buckingham

Bio: E. Buckingham is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 2374 citations.

Encyclopedia of Pharmaceutical Technology

Abstract: Contributors to Volume 19Contents of Other VolumesBlow-Fill-Seal Aseptic ProcessingDeborah J. JonesCompounding, ContemporaryLoyd V. Allen, Jr.Drug Delivery-Oral Colon SpecificVincent H. L. Lee and Suman K. MukherjeeThe European Agency for the Evaluation of Medicinal Product (EMEA)David JacobsHarmonization-CompendiaLee. T. Grady and Jerome A. HalperinInhalation, Dry PowderLynn Van Campen and Geraldine VenthoyeLiquid Crystals in Drug DeliveryChristel C. Mueller-GoymannMedication Errors: A New Challenge for the Pharmaceutical IndustryDiane R. CousinsMucoadhesive Hydrogels in Drug DeliveryHans E. Junginger, Maya Thanou, and J. Coos VerhoefPeptides and Proteins: Buccal AbsorptionHemant H. Alur, and Thomas P. Johnston, and Ashim K. MitraPharmaceutical Quality Assurance Microbiology LaboratoriesAnthony M. CundellProcess Chemistry in the Pharmaceutical IndustryKumar G. Gadamasetti and Ambarish K. SinghRadiolabeling of Pharmaceutical Aerosols and Gamma Scintigraphic Imaging for Lung DepositionHak-Kim ChanSuper Disintegrants: Characterization and FunctionLarry L. Augsburger, Albert W. Brzeczko, Umang Shah, and Huijeong A. HahmIndex to Volume 20

Scale issues in hydrological modelling: A review

Abstract: A framework is provided for scaling and scale issues in hydrology. The first section gives some basic definitions. This is important as researchers do not seem to have agreed on the meaning of concepts such as scale or upscaling. ‘Process scale’, ‘observation scale’ and ‘modelling (working) scale’ require different definitions. The second section discusses heterogeneity and variability in catchments and touches on the implications of randomness and organization for scaling. The third section addresses the linkages across scales from a modelling point of view. It is argued that upscaling typically consists of two steps: distributing and aggregating. Conversely, downscaling involves disaggregation and singling out. Different approaches are discussed for linking state variables, parameters, inputs and conceptualizations across scales. This section also deals with distributed parameter models, which are one way of linking conceptualizations across scales. The fourth section addresses the linkages across scales from a more holistic perspective dealing with dimensional analysis and similarity concepts. The main difference to the modelling point of view is that dimensional analysis and similarity concepts deal with complex processes in a much simpler fashion. Examples of dimensional analysis, similarity analysis and functional normalization in catchment hydrology are given. This section also briefly discusses fractals, which are a popular tool for quantifying variability across scales. The fifth section focuses on one particular aspect of this holistic view, discussing stream network analysis. The paper concludes with identifying key issues and gives some directions for future research.

Perceiving affordances : Visual guidance of stair climbing

Abstract: How do animals visually guide their activities in a cluttered environment? Gibson (1979) proposed that they perceive what environmental objects offer or afford for action. An analysis of affordances in terms of the dynamics of an animal-environment system is presented. Critical points, corresponding to phase transitions in behavior, and optimal points, corresponding to stable, preferred regions of minimum energy expenditure, emerge from variation in the animal-environment fit. It is hypothesized that these points are constants across physically similar systems and that they provide a natural basis for perceptual categories and preferences. In three experiments these hypotheses are examined for the activity of human stair climbing, by varying riser height with respect to leg length. The perceptual category boundary between "climbable" and "unclimbable" stairs is predicted by a biomechanical model, and visually preferred riser height is predicted from measurements of minimum energy expenditure during climbing. It is concluded that perception for the control of action reflects the underlying dynamics of the animal-environment system.

Scaling, dimensional analysis, and indentation measurements

Abstract: We provide an overview of the basic concepts of scaling and dimensional analysis, followed by a review of some of the recent work on applying these concepts to modeling instrumented indentation measurements. Specifically, we examine conical and pyramidal indentation in elastic-plastic solids with power-law work-hardening, in power-law creep solids, and in linear viscoelastic materials. We show that the scaling approach to indentation modeling provides new insights into several basic questions in instrumented indentation, including, what information is contained in the indentation load-displacement curves? How does hardness depend on the mechanical properties and indenter geometry? What are the factors determining piling-up and sinking-in of surface profiles around indents? Can stress-strain relationships be obtained from indentation load-displacement curves? How to measure time dependent mechanical properties from indentation? How to detect or confirm indentation size effects? The scaling approach also helps organize knowledge and provides a framework for bridging micro- and macroscales. We hope that this review will accomplish two purposes: (1) introducing the basic concepts of scaling and dimensional analysis to materials scientists and engineers, and (2) providing a better understanding of instrumented indentation measurements.

Collective Motion, Sensor Networks, and Ocean Sampling

Abstract: This paper addresses the design of mobile sensor networks for optimal data collection. The development is strongly motivated by the application to adaptive ocean sampling for an autonomous ocean observing and prediction system. A performance metric, used to derive optimal paths for the network of mobile sensors, defines the optimal data set as one which minimizes error in a model estimate of the sampled field. Feedback control laws are presented that stably coordinate sensors on structured tracks that have been optimized over a minimal set of parameters. Optimal, closed-loop solutions are computed in a number of low-dimensional cases to illustrate the methodology. Robustness of the performance to the influence of a steady flow field on relatively slow-moving mobile sensors is also explored