41,482 research outputs found
Investigation to identify paint coatings resistive to microorganism growth
All selected coatings contain nutrients that support microbial growth and survival. Incorporation of microbiocidal agents into coatings more susceptible to attack is recommended for improved inhibition of microorganism growth and for increased protection against deterioration of coatings by microorganisms
Investigation of Spacecraft Materials that Support Microorganism Growth
Microorganism growth supporting or biocidal properties of spacecraft paint coating
Investigation of spacecraft materials that support microorganism growth Summary report, 1 Sep. 1968 - 30 Jun. 1970
Investigating spacecraft coatings for resistance to growth of microorganism
Millimeter-wave radiometry for radio astronomy Final report
Lunation study using millimeter wave radiometry for radio astronom
Target value design: using collaboration and a lean approach to reduce construction cost
Target Costing is an effective management technique that has been used in manufacturing for decades to achieve cost predictability during new products development. Adoption of this technique promises benefits for the construction industry as it struggles to raise the number of successful outcomes and certainty of project delivery in terms of cost, quality and time. Target Value Design is a management approach that takes the best features of Target Costing and adapts them to the peculiarities of construction. In this paper the concept of Target Value Design is introduced based on the results of action research carried out on 12 construction projects in the USA. It has been shown that systemic application of Target Value Design leads to significant improvement of project performance – the final cost of projects was on average 15% less than market cost. The construction industry already has approaches that have similarities with elements of the Target Value Design process or uses the same terminology, e.g. Partnering and Target Cost Contracts, Cost planning, etc. Following an exploration of the similarities and differences Target Value Design is positioned as a form of Target Costing for construction that offers a more reliable route to successful projects outcomes
Study of a small solar probe /sunblazer/. part ii- spacecraft and payload design progress report, jul. 1, 1964 - jun. 30, 1965
Design considerations for Sunblazer solar probe and payloa
Understanding adsorption of hydrogen atoms on graphene
Adsorption of hydrogen atoms on a single graphite sheet (graphene) has been
investigated by first-principles electronic structure means, employing
plane-wave based, periodic density functional theory. A reasonably large 5x5
surface unit cell has been employed to study single and multiple adsorption of
H atoms. Binding and barrier energies for sequential sticking have been
computed for a number of configurations involving adsorption on top of carbon
atoms. We find that binding energies per atom range from ~0.8 eV to ~1.9 eV,
with barriers to sticking in the range 0.0-0.2 eV. In addition, depending on
the number and location of adsorbed hydrogen atoms, we find that magnetic
structures may form in which spin density localizes on a
sublattice, and that binding (barrier)
energies for sequential adsorption increase (decrease) linearly with the
site-integrated magnetization. These results can be rationalized with the help
of the valence-bond resonance theory of planar conjugated systems, and
suggest that preferential sticking due to barrierless adsorption is limited to
formation of hydrogen pairs.Comment: 12 pages, 8 figures and 4 table
OPAD 1991
The Optical Plume Anomaly Detection Program, an experimental study in the attempt to create a rocket engine health monitor based on detection and possible quantification of anomalous atomic and molecular species in the exhaust plume, has been in existence for several years. The instruments developed to monitor the exhaust plumes are presented. Two optical instruments are employed: the polychromator and the spectrometer. The polychromator is a 16 channel spectroradiometer having independent channels individually adjustable for center wavelength and pass bandwidth. Those values may be mechanically reset, with the aid of certain lab equipment. The spectrometer is a multichannel spectral analyzer having two 2048 element linear photodiode arrays at the exit plane of the dispersing instrument, which, like the 16 channel device, is a 1/2 meter grating spectrograph. These instruments are equipped with ultraviolet grade multifiber optical input cables, allowing the instruments to be placed in a benign environment. Telescopes mounted on the test stand observe the plume keeping the shock structure in view. The data acquisition and control system consist of four 80386-33 MHz computers: two at the test stand for instrument control and data preconditioning, and two in the test support building providing data archiving, display, and system control. Further descriptions of the instrumentation are provided
Observation of Motion Dependent Nonlinear Dispersion with Narrow Linewidth Atoms in an Optical Cavity
As an alternative to state-of-the-art laser frequency stabilisation using
ultra-stable cavities, it has been proposed to exploit the non-linear effects
from coupling of atoms with a narrow transition to an optical cavity. Here we
have constructed such a system and observed non-linear phase shifts of a narrow
optical line by strong coupling of a sample of strontium-88 atoms to an optical
cavity. The sample temperature of a few mK provides a domain where the Doppler
energy scale is several orders of magnitude larger than the narrow linewidth of
the optical transition. This makes the system sensitive to velocity dependent
multi-photon scattering events (Dopplerons) that affect the cavity field
transmission and phase. By varying the number of atoms and the intra-cavity
power we systematically study this non-linear phase signature which displays
roughly the same features as for much lower temperature samples. This
demonstration in a relatively simple system opens new possibilities for
alternative routes to laser stabilization at the sub 100 mHz level and
superradiant laser sources involving narrow line atoms. The understanding of
relevant motional effects obtained here has direct implications for other
atomic clocks when used in relation with ultranarrow clock transitions.Comment: 9 pages (including 4 pages of Supplemental Information), 6 figures.
Updated to correspond to the published versio
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