Maxwell stress excitation of wire vibrations at difference and sum frequencies of electric currents in separate circuits.

Oscillating electric currents through a wire under tension can excite transverse vibrational modes of the wire when a perpendicular static magnetic field is present and the frequency of the current is close to the natural frequency of the mode of interest. The excitation of the mode is associated with temporally oscillating Maxwell stresses on the wire, often also known as oscillating Lorentz forces. That excitation process is sometimes demonstrated in educational contexts. The investigation here concerns situations where a temporally oscillating magnetic field generated by oscillating electric currents in a cylindrical coil replaces the imposed perpendicular static magnetic field. The frequencies of the currents in the wire and in the coil are related to the frequency of the oscillating stress. In this experiment, this effect is documented for sum-frequency excitation (with input frequencies in the range of half that of the excited lowest vibrational mode of the wire) and the difference-frequency excitation (with input frequencies an order-of-magnitude larger than the mode frequency). This coupling may be useful when it is desirable to use only high-frequency currents. The experiment uses tone-burst stress excitation and a differential photodiode for detecting transverse low-amplitude wire oscillations. Signal envelopes decayed exponentially after the tone-burst.

Successful implementation of a wellness and tobacco cessation curriculum in psychosocial rehabilitation clubhouses.

BACKGROUND: Tobacco remains a seemingly intractable problem for individuals living with severe and persistent mental illness. This study evaluated the implementation, technical assistance, and perceived impact of a model curriculum ("Learning About Healthy Living") to promote wellness and motivation to quit tobacco use in psychosocial rehabilitation clubhouses. METHODS: We used semi-structured interviews (n = 9) with clubhouse staff (n = 12) and a survey of participating clubhouse members (n = 271) in nine clubhouses. RESULTS: Fifty-eight percent of clubhouse participants completed surveys. Results showed tobacco users open to tobacco-free policies (62%) and perceiving more discussions about quitting tobacco with healthcare providers (69%). Analyses of staff interviews and member surveys revealed four key themes: (1) the curriculum was successfully implemented and appreciated; (2) technical assistance kept implementation on track; (3) adding wellness content and interactive components should enhance the curriculum; and, (4) the curriculum advanced other healthful policies and practices. CONCLUSIONS: Mental health settings are important locations for implementing programs to address tobacco use. In this real-world implementation of a model curriculum in psychosocial rehabilitation clubhouses, the curriculum tested well, was feasible and well-received, and suggests potential impact on tobacco use outcomes. Revision, dissemination, and a randomized controlled trial evaluation of the model curriculum should now occur.