This paper deals with the use of a magnetic levitation system as a part of a multi-stage seismic attenuator for gravitational wave interferometric antennas. The proposed configuration uses permanent magnets in attraction to balance the suspended weight, plus a closed loop position control to obtain a stable levitation. The system is analyzed using a MATLAB simulation code to compute the forces ...

Excitation in the outer loop is adjusted to obtain a minimum detected signal at the centered probe. This can be done quite accurately and defines antisymmetric excitation for the antennas (az = —aJ. Antenna #2 is then shorted at the ground plane resulting in (bl/aJ= – 1, and the phase bridge is balanced to produce a null at the detector. This balance occurs when b,= –uZ = al and establishes a p...

This beam detector accepts the narrow pulses typically encountered in electron storage rings. It is composed of a peak detector with a threshold held constant by means of an automatic gain control (AGC) loop, and of a sampler. The output is proportional to the instantaneous position of the beam center of charge and is independent of the beam current. In addition, the very small phase shift of t...

To minimize the pulse-to-pulse variation, the LCLS FEL must operate at saturation, i.e. 10 orders of magnitude brighter spectral brilliance than 3-generation light sources. At this intensity, ultra-high vacuums and windowless transport are required. Many of the experiments, however, will need to be conducted at a much lower intensity thereby requiring a reliable means to reduce the x-ray intens...

A screening assay to test the inducing capacity of macrolides by fusing the attenuator of the inducible erm(B) gene from Streptococcus pneumoniae HM28 with the gfpmut1 gene has been designed. Fluorescence was detected under UV light around disks impregnated with inducer macrolides (erythromycin or azithromycin) but not with noninducer ketolides. Induction could be quantified by fluorometry.

The current paradigm for tuning synthetic biological systems is through re-engineering system components. Biological systems designed with the inherent ability to be tuned by external stimuli will be more versatile. We engineered Escherichia coli cells to behave as an externally tunable band-pass filter for enzyme activity and small molecules. The band's location can be positioned within a rang...