Computational approaches to gene finding

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (leaf 37).by Eric Banks.M.Eng

The action of chlorine trifluoride on benzene in the vapour phase

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Low Earth orbital atomic oxygen environmental simulation facility for space materials evaluation

Simulation of low Earth orbit atomic oxygen for accelerated exposure in ground-based facilities is necessary for the durability evaluation of space power system component materials for Space Station Freedom (SSF) and future missions. A facility developed at the National Aeronautics and Space Administrations's (NASA) Lewis Research Center provides accelerated rates of exposure to a directed or scattered oxygen beam, vacuum ultraviolet (VUV) radiation, and offers in-situ optical characterization. The facility utilizes an electron-cyclotron resonance (ECR) plasma source to generate a low energy oxygen beam. Total hemispherical spectral reflectance of samples can be measured in situ over the wavelength range of 250 to 2500 nm. Deuterium lamps provide VUV radiation intensity levels in the 115 to 200 nm range of three to five equivalent suns. Retarding potential analyses show distributed ion energies below 30 electron volts (eV) for the operating conditions most suited for high flux, low energy testing. Peak ion energies are below the sputter threshold energy (approximately 30 eV) of the protective coatings on polymers that are evaluated in the facility, thus allowing long duration exposure without sputter erosion. Neutral species are expected to be at thermal energies of approximately .04 eV to .1 eV. The maximum effective flux level based on polyimide Kapton mass loss is 4.4 x 10 exp 6 atoms/((sq. cm)*s), thus providing a highly accelerated testing capability

Matrix inequalities with applications to the theory of iterated kernels

NOTICE: this is the author's version of a work that was accepted for publication in Linear Algebra and its Applications. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Linear Algebra and its Applications, Volume 362 (2003), pp.275-286. doi:10.1016/S0024-3795(02)00517-7. http://www.elsevier.com/locate/laa.For an m × n matrix A with nonnegative real entries, Atkinson, Moran and Watterson proved the inequality s(A)3 ≤ mns(AAtA), where At is the transpose of A, and s(·) is the sum of the entries. We extend this result to finite products of the form AAtAAt . . .A or AAtAAt . . .At and give some applications to the theory of iterated kernels

Operation of a Small Tethered Payload

This paper presents results of a study currently being performed at Stanford University sponsored by NASA/Goddard Space Station Small Attached Payloads. The use of tethers as a means of dynamic isolation for small attached payloads shows promise in reducing orbital maneuvering vehicle requirements to service co-orbiting facilities while still providing a stable contamination-free platform for precision pointing instruments. Thethers may also be used as a means of deorbiting small sample return vehicles. These return vehicles might be dedicated small experiment carriers for a specific mission and require little manned interaction, or they might be loaded with experimental samples for de-orbit and reentry. Another application lies in electrodynamic tether research for ionospheric and vehicle charging and potential studies to continue the effort initiated with the Space Shuttle Tethered Satellite System. The study focuses on defining the issues and resource requirements for small tethered payloads. Areas highlighted include attachment and structural interfaces, communication and data handling facilities, power and electrical interfaces, and dynamics and proximity operations issues

Vacuum Pyrolysis and Related ISRU Techniques

A number of ISRU-related techniques have been developed at NASA Goddard Space Flight Center. The focus of the team has been on development of the vacuum pyrolysis technique for the production of oxygen from the lunar regolith. However, a number of related techniques have also been developed, including solar concentration, solar heating of regolith, resistive heating of regolith, sintering, regolith boiling, process modeling, parts manufacturing, and instrumentation development. An initial prototype system was developed to vaporize regolith simulants using a approx. l square meter Fresnel lens. This system was successfully used to vaporize quantities of approx. lg, and both mass spectroscopy of the gasses produced and Scanning Electron Microscopy (SEM) of the slag were done to show that oxygen was produced. Subsequent tests have demonstrated the use of a larger system With a 3.8m diameter reflective mirror to vaporize the regolith. These results and modeling of the vacuum pyrolysis reaction have indicated that the vaporization of the oxides in the regolith will occur at lower temperature for stronger vacuums. The chemical modeling was validated by testing of a resistive heating system that vaporized quantities of approx. 10g of MLS-1A. This system was also used to demonstrate the sintering of regolith simulants at reduced temperatures in high vacuum. This reduction in the required temperature prompted the development of a small-scale resistive heating system for application as a scientific instrument as well as a proof-of principle experiment for oxygen production

California Solar Regatta

This Final Design Review report details the research, analysis, and design conducted by a Cal Poly Mechanical Engineering senior project team working on the propulsion system for a solar powered boat. Working in coordination with another senior project team responsible for making the hull, the two teams comprised the Cal Poly team who entered the Sacramento Municipal Utility District (SMUD) 2020 California Solar Regatta Competition. The SMUD Solar Regatta is an annual competition for high school and college students to design and build boats powered by solar power. The solar panels are provided by SMUD, and the battery storage is limited by competition regulations. The scope of this project was to design a propulsion system that would efficiently transfer energy, be easily integrated into the hull design and be competitive in the three races: endurance, slalom, and sprint. This document covers research conducted, objectives for the design, design concepts considered, the chosen final design, manufacturing and verification plans, and project management