Experimental dynamic stiffness and damping of externally pressurized gas-lubricated journal bearings

A rigid vertical shaft was operated with known amounts of unbalance at speeds to 30,000 rpm and gas supply pressure ratios to 4.8. From measured amplitude and phase angle data, dynamic stiffness and damping coefficients of the bearings were determined. The measured stiffness was proportional to the supply pressure, while damping was little affected by supply pressure. Damping dropped rapidly as the fractional frequency whirl threshold was approached. A small-eccentricity analysis overpredicted the stiffness by 20 to 70 percent. Predicted damping was lower than measured at low speeds but higher at high speeds

Education’s Role in Democracy: The Power of Pluralism

My task in Beyond Liberal Democracy in Schools (2008) was to develop a relational, pluralistic social political theory that moves beyond liberal democracy. I find Dewey is a key source to help us find our way out of liberal democracy’s assumptions and show us how to move on. He (1949/1960) offers us the possibilities of moving beyond individualism, with his theory of social transaction and he (1938/1955) shows us how to move beyond rationalism in his arguments for truths as warranted assertions. A transactional description of selves-in-relation-with-others describes us as becoming individuals out of our social settings. At the same time that we are becoming individuals within a social setting, we are continually affecting that social setting. Individuals are not aggregates with separate boundaries that have no relation to one another. In fact, the ‘self’ is fictive, and contingent. Our ‘selves’ are multifarious and fractured, due to repressive forces imposed upon us by others as well as supportive forces offered to us by others. Others bind us and help us become free at the same time. The democratic theory I develop is a radical democratic theory that represents feminist and multicultural concerns. This theory is radical because of my efforts to present an anti-racist theory that critiques basic foundational-level assumptions embedded within both individualism and collectivism. The theory moves beyond modernism and critical theory as it seeks to address postmodern concerns of power and exclusionary practice without appealing to grand narratives such as Reason, the Scientific Method, or Dialogue. I follow Dewey’s social transactional lead and describe our world as one that is pluralistic, relational, and in process as we continually contribute to the on-going constructing of knowing. I argue, in agreement with Dewey (1916/1996), that a democracy is a mode of associated living, not just a view of political democracy, and that it needs to be struggled for on all fronts, with all our social institutions, including: political, economic, educational, scientific, artistic, religious, and familial. This comprehensive view of democracy is consistent with the transactional relational assumption I describe, for it recognizes that social institutions are no more autonomous and separate from each other than individuals are separate from each other. For this essay, I explore education’s role in helping us understand how connected we all are to each other, moving us closer to living in a world we may someday call a democracy

Analysis of intrapulse chirp in CO2 oscillators

Pulsed single-frequency CO2 laser oscillators are often used as transmitters for coherent lidar applications. These oscillators suffer from intrapulse chirp, or dynamic frequency shifting. If excessive, such chirp can limit the signal-to-noise ratio of the lidar (by generating excess bandwidth), or limit the velocity resolution if the lidar is of the Doppler type. This paper describes a detailed numerical model that considers all known sources of intrapulse chirp. Some typical predictions of the model are shown, and simple design rules to minimize chirp are proposed

Contributors

List of Contributors and Guidelines for Contributors

Releasing the Imagination: Essays on Education, the Arts, and Social Change by Maxine Greene

How does imagination help us as inquirers? Assuming the value of imagination for inquiry, what should teachers and schools do to help encourage and further develop students\u27 imaginative abilities? These are two questions I have been considering lately, and I have found two excellent sources to help me. I want to share them with you, the reader, first on an individual basis (as they are each worthy of their own review), then together to highlight their common bonds. Mary Catherine Bateson uses Peripheral Visions as an opportunity to reflect on her life and some of the key experiences she had that helped her learn to meet uncertainty through responsible improvision and to develop a habit of reflection. Maxine Greene also writes Releasing the Imagination as a series of essays reflecting on art that she has experienced through the years, especially literary art, which helped her learn to be wide-awake, open, and attending to the world around her

Editorial Comments

This issue of International Education begins with a focus on a particular preschool in P.R. China, and then turns its attention to school reform policy in Finland and professional development of teachers in the U.S., as well as support for special education teachers in Jordan