The Effect of Water Quality Characteristics on Cavitation Noise
This study investigated the effects of seawater on cavitation noise using a water jet test, a two-dimensional wing test, and a three-dimensional wing test. A model propeller cavitation test was conducted in a cavitation tunnel using seawater, in order to determine the effects of propeller cavitation more precisely. In the cavitation tests, measured propeller performance for both cavitation noise inception and desinence, as well as the cavitation noise spectrum (see, for example, figure 7). On the basis of the results of the present propeller cavitation test and tests that were carried out previously, we discuss how to control the water quality in the cavitation tunnel to reproduce the cavitation phenomena, especially cavitation noise, in seawater (see, for example, figure 9).
Cavitation Nuclei and Cavitation Inception of Marine Propellers: State of the Art at the Dawn of the 21st Century.
The important role of nuclei on cavitation inception and cavitation development is now well known. Several recent studies have allowed a precise correlation between cavitation inception for different types of cavitation on marine propellers and nuclei distributions (20th ITTC report). In a standard cavitation facility the nuclei distribution will depend on the hydrodynamic operating conditions, and can change during whole cavitation tests. Then, to be able to transpose the model results to full-scale. it is necessary to determine precisely the nuclei distribution corresponding to each cavitation operating point. An illustration is given by analyzing the influence of the operating conditions on a complete cavitation inception «bucket». Moreover, as nuclei govern the whole cavitation process, nuclei measurements are also conducted at sea. The main purpose of all these studies is the accurate prediction of full-scale cavitation behavior from precise transposition laws. This is possible only when nuclei distributions are determined
Evaluating Cultural Authenticity in Multicultural Picture Books: A Collaborative Analysis for Diversity Education
This study examines cultural authenticity reflected in multicultural picture books. Specifically, this study attempts to reframe issues surrounding the topic of cultural authenticity based on a systematic and empirical analysis of picture books that represent three different ethnic groups: African Americans, Asian Americans, and Hispanic Americans. A total of forty-five systematically selected picture books that represent fifteen books per ethnic group were selected and evaluated by multiple reviewers who were insiders of the culture. A coding scheme was developed to evaluate each book in terms of profile of major and minor characters, settings of the story, stereotypical features, and cultural authenticity. An in-depth evaluation of all selected books was added by a team of three reviewers in order to validate the results of the coded analysis. This study aims to shed light on library youth services and diversity education in a society with increasing ethnic diversity.