A comparison of experimental and theoretical results for rotordynamic coefficients of four annular gas seals

The test facility and initial test program developed to experimentally measure the fluid forces induced by annular gas seals is described. A comparison of theoretically predicted and experimentally obtained data for smooth and honeycomb seals is provided. And a comparison of experimental data from the tests of three smooth-rotor/smooth-stator seals is provided. The leakage of the working fluid through the seal, the pressure gradient along the seal length, entrance pressure-loss data, and rotordynamic coefficients provide a basis for comparison. A short discussion on seal theory is included, and various rotordynamic coefficient identification schemes are described

The development and application of a systematic approach to evaluating an academic department\u27s brand meaning

Research of existing literature indicates that below the university level, there has been little effort made in branding academia, namely academic departments. The lack of branding may significantly affect the perceptions that potential students and future employers of these students have about one of these academic units. The impact may be most significant for units where the fields of study that are represented by the department may be unclear, such as in the case of engineering management. However, even in the cases of better-understood fields of study, for example, electrical engineering, the competition for students with other fields of study and within the field of study itself may drive the need for better branding. A model for assessing and understanding a brand\u27s meaning for an intangible service as provided by an academic department has been developed and applied to the case of an engineering management department --Abstract, page iii

Analysis of navigation performance for the Earth Observing System (EOS) using the TDRSS Onboard Navigation System (TONS)

Use of the Tracking and Data Relay Satellite System (TDRSS) Onboard Navigation System (TONS) was proposed as an alternative to the Global Positioning System (GPS) for supporting the Earth Observing System (EOS) mission. The results are presented of EOS navigation performance evaluation with respect to TONS based orbit, time, and frequency determination (OD/TD/FD). Two TONS modes are considered: one uses scheduled TDRSS forward link service to derive one way Doppler tracking data for OD/FD support (TONS-I); the other uses an unscheduled navigation beacon service (proposed for Advanced TDRSS) to obtain pseudorange and Doppler data for OD/TD/FD support (TONS-II). Key objectives of the analysis were to evaluate nominal performance and potential sensitivities, such as suboptimal tracking geometry, tracking contact scheduling, and modeling parameter selection. OD/TD/FD performance predictions are presented based on covariance and simulation analyses. EOS navigation scenarios and the contributions of principal error sources impacting performance are also described. The results indicate that a TONS mode can be configured to meet current and proposed EOS position accuracy requirements of 100 and 50 m, respectively

Dynamic response of a double squeeze-film thrust plate

Dynamic response of gaseous double squeeze film thrust plate for bearing

On the slowly time dependent problem of squeeze film bearings

Time dependency of spherical squeeze-film bearing for use in suspension of precision gyroscope outpu

Variable valve actuating apparatus

An actuating apparatus, which can be used to perform variable valve timing of the intake or exhaust valves of an internal combustion engine, includes a hollow shaft with at least one slot defined through a cylindrical wall. A movable cam member is disposed to project through the slot and is rotatable relative to the hollow shaft in a channel defined in the interior surface of the hollow shaft. A base circle band extends circumferentially around the outer surface of the hollow shaft between the endwalls of the slot. The exterior surface of the hollow shaft can define grooves which receive front or back ear members of the cam member. The exterior surface of the hollow shaft also can define recesses, which in some embodiments have bottom surfaces and in other embodiments have partial bottom surfaces or no bottom surface. The recesses can receive tongue members formed on the cam member. The cam member can be engaged by a cam follower that has a roller to engage the cam surface. When the length of the roller exceeds the width of the cam surface, base circle arcuate sections can be provided on the exterior surface of the hollow shaft to carry the roller across the exposed portion of the slot that exists between the endwall of the slot and the free end of the cam member. An inner shaft extends through an opening defined transversely through the cam member and nonrotatably engages same. The nose portion of the cam member can be defined by a rotatable roller. Twin cam members having identical cam surface profiles can be disposed side-by-side, with one cam member projecting through the slot and the other cam member secured to the outer surface of the hollow shaft. A single follower such as a tappet defining a circular cylindrical surface can be provided to engage both cam members and can be held nonrotatably

“It’s a Two-Way Street”: Giving Feedback in a Teacher Writing Group

Abstract: A consistent feature of teacher writing groups is the giving and receiving of feedback on writing. While there have been several studies that have explored the effects of receiving feedback on one\u27s own writing, there have only been a few that explored the effects of providing feedback to others can have on a teacher’s own work. Drawing on interviews with teacher-writers who work together in a writing group, we conclude that giving feedback transforms the writing lives of all participants involved in the feedback process through experiences of reciprocity, involving claiming authority within a community of writers, developing rapport, and challenging hierarchies of writing teacher and writing student