An oil pipeline design problem

Copyright @ 2003 INFORMSWe consider a given set of offshore platforms and onshore wells producing known (or estimated) amounts of oil to be connected to a port. Connections may take place directly between platforms, well sites, and the port, or may go through connection points at given locations. The configuration of the network and sizes of pipes used must be chosen to minimize construction costs. This problem is expressed as a mixed-integer program, and solved both heuristically by Tabu Search and Variable Neighborhood Search methods and exactly by a branch-and-bound method. Two new types of valid inequalities are introduced. Tests are made with data from the South Gabon oil field and randomly generated problems.The work of the first author was supported by NSERC grant #OGP205041. The work of the second author was supported by FCAR (Fonds pour la Formation des Chercheurs et l’Aide à la Recherche) grant #95-ER-1048, and NSERC grant #GP0105574

Algebras for Tree Decomposable Graphs

n/

[Epidemiologic study in nursery schools of the Verona Commune on the occurrence of dental caries, malocclusion and bad habits that can influence the normal development of facial bone structure in children]

A large sample of children aged 3 to 6 was investigated for the presence of caries, malocclusions and bad habits. The study highlighted the correlation between bad habits and impaired development of facial skeletal structure

[Clinico-therapeutic considerations in a serious case of amelogenesis imperfecta]

: The Authors present a case of a young female patient affected with a serious hypoplasic form of Amelogenesis Imperfecta, involving all the teeth which has been completely restabilished using composite resin. The therapy used has been developed thanks to the chemical-physical qualities of last generation of composites, which allow the compete reconstruction of teeth. Such a therapy has not to be considered definitive, however it has been used as a temporary solution, waiting for final prosthetic rehabilitation. The Authors estimate that such a temporary long term treatment, that utilize composite resins, represent the ideal therapeutical choice thanks to its characteristics of endurance, cost and benefice. In our opinion this therapy prevents tooth deterioration, secures a better mastication, a partial reduction of the teeth sensibility, facilitates teeth cleaning and solves the esthetical problems with great psychological advantage