Clebsch Potentials in the Variational Principle for a Perfect Fluid

Equations for a perfect fluid can be obtained by means of the variational principle both in the Lagrangian description and in the Eulerian one. It is known that we need additional fields somehow to describe a rotational isentropic flow in the latter description. We give a simple explanation for these fields; they are introduced to fix both ends of a pathline in the variational calculus. This restriction is imposed in the former description, and should be imposed in the latter description. It is also shown that we can derive a canonical Hamiltonian formulation for a perfect fluid by regarding the velocity field as the input in the framework of control theory.Comment: 15 page

A Variational Principle for Dissipative Fluid Dynamics

In the variational principle leading to the Euler equation for a perfect fluid, we can use the method of undetermined multiplier for holonomic constraints representing mass conservation and adiabatic condition. For a dissipative fluid, the latter condition is replaced by the constraint specifying how to dissipate. Noting that this constraint is nonholonomic, we can derive the balance equation of momentum for viscous and viscoelastic fluids by using a single variational principle. We can also derive the associated Hamiltonian formulation by regarding the velocity field as the input in the framework of control theory.Comment: 15 page

Studies at Oyster Bay in Jamaica, West Indies. II. Effacts of flow patterns and exchange on bioluminescent distributions

From July 1966 to July 1967, regular observations and some experiments were carried out in Oyster Bay at the eastern end of Falmouth Harbor, Jamaica, W. I. This paper gives a general description of the area; it reports observations on the tidal movement, the density currents, the wind force and direction, and the water discharge by the Martha Brae River; and it correlates the flow patterns in Oyster Bay with observed bioluminescent distribution

Studies at Oyster Bay in Jamaica, West Indies. III. Measurements of underwater-sunlight spectra

Spectral distributions of ambient underwater sunlight in Oyster Bay, Falmouth Harbor, Jamaica, West Indies, have been measured during the diurnal rise in the stimulable bioluminescent intensity of the marine dinoflagellate, Pyrodinium bahamense. In addition to the changes in light intensity during this period, there are large changes in the relative spectral distributions, as functions of both time and depth in the Bay. The blue-to-red intensity ratios vary by factors of 10 to 100

Studies at Oyster Bay in Jamaica, West Indies. I. Intensity patterns of bioluminescence in a natural environment

Night and day patterns in the intensities of stimulable bioluminescense in Pyrodinium bahamense were measured during the period of April 1966 through May 1967 in Oyster Bay, Falmouth Harbor, Jamaica, West Indies…

Ion engine thrust vector study, phase 2 Quarterly report

Performance prediction for expected thrust misalignment in electron bombardment ion thruste

Guidelines for the Definition of Innovative Industrial Product-service Systems (PSS) Business Models for Remanufacturing

AbstractRemanufacturing represents a well-suited approach for sustainable development in environmental, economic and social dimensions. Product-service systems (PSS) are among the most important enabler for remanufacturing. Companies that remain owner of a product have an intrinsic motivation to design goods for longer lifecycles considering the possibility of remanufacturing the product or its parts after each use phase. In addition, as the end customer only uses the goods without having its ownership, the acceptance – and consequently the demand – for remanufactured goods is significantly improved. This paper presents guidelines for the definition of innovative business models for remanufacturing, utilizing both remanufacturing and PSS characteristics, and permitting the dissemination of knowledge needed for successful implementation within a company strategy and operations model. Focusing on industrial PSS, an illustrative application of the guidelines is demonstrated