550 research outputs found
Homelessness and De-Institutionalization
The nation faces a social problem caused by the discharge of chronic mentally ill patients to the community through a process known as deinstitutionalization. Frequently hcmeless, these individuals require many community supports and have aroused public sentiment. A review of current literature is used to validate these observations. The University of Connecticut has initiated a practicn training project to educate case managers in serving the hcmeless mentally ill. From an historical perspective, this study outlines the evolution of deinstitutionalization and the identification of treatment models applied to this process
Identification of Resonant Frequencies in LIGO-like Suspension with Finite-Element Modeling
Following the upgrades to Advanced LIGO (aLIGO), measurements were made of
the detector suspensions' frequency response characteristics. While most
resonant frequencies could be identified with simple mechanical models, such as
the fiber vibration modes, some were unexplained. Using a finite element model
of the quadruple pendulum suspension, we search for and identify lines from
unknown sources. The present work focuses on two resonant lines observed in the
Upper Intermediate Mass as examples of this technique. Our simulations suggest
a common source for these lines, which could be accounted for in a redesign. By
modeling these response frequencies, we can examine the motion of individual
components, and suggest methods to reduce their amplitude, alter their
frequency, or eliminate them in future gravitational wave detector designs
Miniature Optical Communications Transceiver (MOCT)
This project will advance the technology readiness of the Miniature Optical Communications Transceiver (MOCT) from TRL 3 to TRL 4. MOCT consists of a novel software-defined pulse modulator (SDPM),integrated laser system, and avalanche photodetection system, and is designed for optical communications between small spacecraft, including CubeSats, using a pulse position modulation (PPM) scheme. PPM encodes data in the timing of optical pulses with respect to a set of timing windows known as slots. The MOCT design focuses on power-efficiency making it particularly interesting for small satellites. We have demonstrated in the laboratory that this technology can generate shorter than 1 nanosecond-wide 1550 nanometer (nm) optical pulses with better than 50 picosecond (ps) timing accuracy. The timing resolution of this system is roughly a factor of four better than previously flown systems, meaning that it can transmit more bits of data with each optical pulse. Because this technology can both generate and time stamp the arrival of short optical pulses with 50 ps precision, it simultaneously provides power efficient communications and relative ranging between small spacecraft at the centimeter (cm) level
Astro2020 White Paper: A Direct Measure of Cosmic Acceleration
Nearly a century after the discovery that we live in an expanding Universe,
and two decades after the discovery of accelerating cosmic expansion, there
remains no direct detection of this acceleration via redshift drift - a change
in the cosmological expansion velocity versus time. Because cosmological
redshift drift directly determines the Hubble parameter H(z), it is arguably
the cleanest possible measurement of the expansion history, and has the
potential to constrain dark energy models (e.g. Kim et al. 2015). The challenge
is that the signal is small - the best observational constraint presently has
an uncertainty several orders of magnitude larger than the expected signal
(Darling 2012). Nonetheless, direct detection of redshift drift is becoming
feasible, with upcoming facilities such as the ESO-ELT and SKA projecting
possible detection within two to three decades. This timescale is uncomfortably
long given the potential of this cosmological test. With dedicated experiments
it should be possible to rapidly accelerate progress and detect redshift drift
with only a five-year observational baseline. Such a facility would also be
ideal for precision radial velocity measurements of exoplanets, which could be
obtained as a byproduct of the ongoing calibration measurements for the
experiment.Comment: White paper submitted to the Astro2020 Decadal Survey. 6 page
- …