The effect of forward speed on ship roll damping

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1983.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERINGIncludes bibliographical references.by Douglas Bruce Colbourne.M.S

A three component method of analyzing icebreaking resistance

This thesis presents a broad based review of current literature in the field of ship icebreaking and ice mechanics relevant to icebreaking. -- A dimensional analysis of the ship icebreaking problem is presented, leading to a system of non-dimensional numbers based on division of the problem into three independent components; an ice breaking component, an ice clearing component and a viscous drag component. Results from a comprehensive set of model tests are presented, validating the three component analysis method. In addition the method is applied to a number of model scale and full scale data sets with considerable success. It is concluded that testing and analysis of icebreaking by dividing the problem into components is practically feasible and offers an improved method of analysis, presentation and scaling

Epidemiology and Infectivity of Plasmodium falciparum and Plasmodium vivax Gametocytes in Relation to Malaria Control and Elimination

Summary: Malaria remains a major cause of morbidity and mortality in the tropics, with Plasmodium falciparum responsible for the majority of the disease burden and P. vivax being the geographically most widely distributed cause of malaria. Gametocytes are the sexual-stage parasites that infect Anopheles mosquitoes and mediate the onward transmission of the disease. Gametocytes are poorly studied despite this crucial role, but with a recent resurgence of interest in malaria elimination, the study of gametocytes is in vogue. This review highlights the current state of knowledge with regard to the development and longevity of P. falciparum and P. vivax gametocytes in the human host and the factors influencing their distribution within endemic populations. The evidence for immune responses, antimalarial drugs, and drug resistance influencing infectiousness to mosquitoes is reviewed. We discuss how the application of molecular techniques has led to the identification of submicroscopic gametocyte carriage and to a reassessment of the human infectious reservoir. These components are drawn together to show how control measures that aim to reduce malaria transmission, such as mass drug administration and a transmission-blocking vaccine, might better be deployed