Space shuttle rudder/speedbrake actuation subsystem

The Rudder/Speedbrake (R/SB) Actuation Subsystem for use on the NASA Space Shuttle Orbiter is an electro-hydro-mechanical system which provides the control and positionary capability of the orbiter aero-dynamic primary flight control surface. The system is located in the vehicle's vertical stabilizer. The geared rotary actuators provide a power hinge feature of the split panel rudder. Actuation of both panels in the same direction provides conventional rudder control; actuating the panels differentially provides a speedbrake function intended to control both speed and pitch. The commands may be superimposed on one another. The system consists of one power drive unit which responds to quadredundant avionic signals to generate a rotary output, four geared rotary actuators, which develop rotary position and torque as outputs, and ten torque transmitting drive-shifts

Soundgen : a Web services based sound generation system for the psychoacoustics laboratory

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references.Soundgen is a web services based sound generation system developed for the MIT Psychoacoustics Laboratory Course 6.I82. The sounds created by Soundgen are combinations of various tones and noises, produced by a dedicated server running Linux, MATLAB, Apache, and PHP. As an example, Soundgen can generate a sound containing two tones of 500ms duration, each with its own frequency and phase, and can produce them over a broadband background noise. The characteristics of the tones and noises are passed to the Soundgen web service via aJSON object sent over HTTP. When the generation is complete, the web service replies with another JSON object containing the URL of the generated sound .wav file, along with some related information. Accompanying the Soundgen web service is a smallJavaScript library, easing the web service's use inJavaScript. This library allows JavaScript programmers to simply call a soundgen() function, which triggers a callback function that executes when the request has been processed by Soundgen. The library and web service allow Psychoacoustics Laboratory students to quickly and easily create portable acoustics experiments as web-applications, which can be written and run on any computer with speakers and a modern web browser.by Michael R. Naber.M.Eng

Raman transitions between hyperfine clock states in a magnetic trap

We present our experimental investigation of an optical Raman transition between the magnetic clock states of $^{87}$Rb in an atom chip magnetic trap. The transfer of atomic population is induced by a pair of diode lasers which couple the two clock states off-resonantly to an intermediate state manifold. This transition is subject to destructive interference of two excitation paths, which leads to a reduction of the effective two-photon Rabi-frequency. Furthermore, we find that the transition frequency is highly sensitive to the intensity ratio of the diode lasers. Our results are well described in terms of light shifts in the multi-level structure of $^{87}$Rb. The differential light shifts vanish at an optimal intensity ratio, which we observe as a narrowing of the transition linewidth. We also observe the temporal dynamics of the population transfer and find good agreement with a model based on the system's master equation and a Gaussian laser beam profile. Finally, we identify several sources of decoherence in our system, and discuss possible improvements.Comment: 10 pages, 7 figure

Radiation effects in silicon solar cells Quarterly report

Effect of lithium on production and annealing of damage in silico

A novel N-terminal extension in mitochondrial TRAP1 serves as a thermal regulator of chaperone activity.

Hsp90 is a conserved chaperone that facilitates protein homeostasis. Our crystal structure of the mitochondrial Hsp90, TRAP1, revealed an extension of the N-terminal β-strand previously shown to cross between protomers in the closed state. In this study, we address the regulatory function of this extension or 'strap' and demonstrate its responsibility for an unusual temperature dependence in ATPase rates. This dependence is a consequence of a thermally sensitive kinetic barrier between the apo 'open' and ATP-bound 'closed' conformations. The strap stabilizes the closed state through trans-protomer interactions. Displacement of cis-protomer contacts from the apo state is rate-limiting for closure and ATP hydrolysis. Strap release is coupled to rotation of the N-terminal domain and dynamics of the nucleotide binding pocket lid. The strap is conserved in higher eukaryotes but absent from yeast and prokaryotes suggesting its role as a thermal and kinetic regulator, adapting Hsp90s to the demands of unique cellular and organismal environments

Radiation effects in silicon solar cells Quarterly progress report, 1 Jul. - 30 Sep. 1970

Defects responsible for degradation in output of silicon solar cells irradiated by space radiatio

Mandatory HIV Testing Issues in State Newborn Screening Programs

The newborn screening model is fairly straightforward. Typically, before the infant is discharged from the hospital (around 24 to 36 hours of age), heel stick blood is placed on special filter paper, dried, and mailed to the state health department for testing. Medical and laboratory research has led to the discovery that other diseases could also be screened in newborns using these dried blood specimens. Currently, all states and the District of Columbia test all newborns for at least PKU and congenital hypothyroidism. There are generally five criteria to satisfy before a disease is considered appropriate for newborn screening: 1. The disease must be well defined and serious enough to justify mass screening; 2. There must be an accurate testing method available; 3. The cost of the test must be reasonable; 4. There must be available treatment for the disorder; and 5. There must be adequate medical management facilities to refer infants for confirmatory diagnosis and treatment. Although newborn screening is often classified as genetic screening, these criteria do not require that the screened disorder have a genetic origin. In fact, congenital hypothyroidism, which is part of every newborn screening program in this country, is usually not a genetic disease

Mandatory HIV Testing Issues in State Newborn Screening Programs

The newborn screening model is fairly straightforward. Typically, before the infant is discharged from the hospital (around 24 to 36 hours of age), heel stick blood is placed on special filter paper, dried, and mailed to the state health department for testing. Medical and laboratory research has led to the discovery that other diseases could also be screened in newborns using these dried blood specimens. Currently, all states and the District of Columbia test all newborns for at least PKU and congenital hypothyroidism. There are generally five criteria to satisfy before a disease is considered appropriate for newborn screening: 1. The disease must be well defined and serious enough to justify mass screening; 2. There must be an accurate testing method available; 3. The cost of the test must be reasonable; 4. There must be available treatment for the disorder; and 5. There must be adequate medical management facilities to refer infants for confirmatory diagnosis and treatment. Although newborn screening is often classified as genetic screening, these criteria do not require that the screened disorder have a genetic origin. In fact, congenital hypothyroidism, which is part of every newborn screening program in this country, is usually not a genetic disease

Trapping of Rydberg Atoms in Tight Magnetic Microtraps

We explore the possibility to trap Rydberg atoms in tightly confining magnetic microtraps. The trapping frequencies for Rydberg atoms are expected to be influenced strongly by magnetic field gradients. We show that there are regimes where Rydberg atoms can be trapped. Moreover, we show that so-called magic trapping conditions can be found for certain states of rubidium, where both Rydberg atoms and ground state atoms have the same trapping frequencies. Magic trapping is highly beneficial for implementing quantum gate operations that require long operation times