2,359 research outputs found
Continuous detection of viable micro-organisms by chemiluminescence
System monitors quality of reclaimed water continuously and automatically. Incubated samples are compared with unincubated ones by measuring their respective chemiluminescence
Automated monitoring of recovered water quality
Laboratory prototype water quality monitoring system provides automatic system for online monitoring of chemical, physical, and bacteriological properties of recovered water and for signaling malfunction in water recovery system. Monitor incorporates whenever possible commercially available sensors suitably modified
Beam Induced Electron Cloud Resonances in Dipole Magnetic Fields
The buildup of low energy electrons in an accelerator, known as electron
cloud, can be severely detrimental to machine performance. Under certain beam
conditions, the beam can become resonant with the cloud dynamics, accelerating
the buildup of electrons. This paper will examine two such effects:
multipacting resonances, in which the cloud development time is resonant with
the bunch spacing, and cyclotron resonances, in which the cyclotron period of
electrons in a magnetic field is a multiple of bunch spacing. Both resonances
have been studied directly in dipole fields using retarding field analyzers
installed in the Cornell Electron Storage Ring (CESR). These measurements are
supported by both analytical models and computer simulations
Studies of Photo-Emission and Field Emission in an RF Photo-Injector with a High Quantum Efficiency Photo-Cathode
The influence of the injection process on the operating behavior of small liquid rockets. Part 1 - Hydrodynamic variables in the fuel injection by impinging jets
Injection process influence on operating behavior of small liquid rockets - Hydrodynamic variables in fuel injection by impinging jet
The effect of interplanetary trajectory options on a manned Mars aerobrake configuration
Manned Mars missions originating in low Earth orbit (LEO) in the time frame 2010 to 2025 were analyzed to identify preferred mission opportunities and their associated vehicle and trajectory characteristics. Interplanetary and Mars atmospheric trajectory options were examined under the constraints of an initial manned exploration scenario. Two chemically propelled vehicle options were considered: (1) an all propulsive configuration, and (2) a configuration which employs aerobraking at Earth and Mars with low lift/drag (L/D) shapes. Both the interplanetary trajectory options as well as the Mars atmospheric passage are addressed to provide a coupled trajectory simulation. Direct and Venus swingby interplanetary transfers with a 60 day Mars stopover are considered. The range and variation in both Earth and Mars entry velocity are also defined. Two promising mission strategies emerged from the study: (1) a 1.0 to 2.0 year Venus swingby mission, and (2) a 2.0 to 2.5 year direct mission. Through careful trajectory selection, 11 mission opportunities are identified in which the Mars entry velocity is between 6 and 10 km/sec and Earth entry velocity ranges from 11.5 to 12.5 km/sec. Simulation of the Earth return aerobraking maneuver is not performed. It is shown that a low L/D configuration is not feasible for Mars aerobraking without substantial improvements in the interplanetary navigation system. However, even with an advanced navigation system, entry corridor and aerothermal requirements restrict the number of potential mission opportunities. It is also shown that for a large blunt Mars aerobrake configuration, the effects of radiative heating can be significant at entry velocities as low as 6.2 km/sec and will grow to dominate the aerothermal environment at entry velocities above 8.5 km/sec. Despite the additional system complexity associated with an aerobraking vehicle, the use of aerobraking was shown to significantly lower the required initial LEO weight. In comparison with an all propulsive mission, savings between 19 and 59 percent were obtained depending upon launch date
Diastereofacial selectivity in reactions of substituted cyclohexyl radicals. An experimental and theoretical study
Refitting long term PMMA wearers: A preliminary study of corneal rehabilitation with gas permeable RX-56 lenses
Corneal exhaustive syndrome is a term which has been used to describe a number of long term PMMA contact lense wearers who either drop out of contacts or require some sort of refitting to remain in contact lenses. Four patients were refit with RX-56 lenses with a specific fitting philosophy of apical clearance and the physiological responses were monitored. Preliminary findings indicate initial corneal flattening with a corresponding decrease in spectacle minus refractive power, followed by corneal steepening and an increase in spectacle minus power. Corneal thinning occurred across the entire horizontal corneal meridian, and in two cases with mild keratometer mire distortion, distortion was eliminated. For the three patients that had pre-wear contact lense data available, there was not a return to the original base line prefit parameters. But the findings did show changes which suggest the same pattern of change as would be found with lens withdrawal or reduced wearing time. Additional study with larger samples and control groups are needed
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