6,696 research outputs found
A New Technic for Measuring the Effect of Practice upon Individual Differences (Abstract)
It was suggested that the analysis of variance lends itself to this problem better than the conventional methods of measuring intercorrelations and standard deviations. An illustrative case was given
Role of coronal mass ejections in the heliospheric Hale cycle
[1] The 11-year solar cycle variation in the heliospheric magnetic field strength can be explained by the temporary buildup of closed flux released by coronal mass ejections (CMEs). If this explanation is correct, and the total open magnetic flux is conserved, then the interplanetary-CME closed flux must eventually open via reconnection with open flux close to the Sun. In this case each CME will move the reconnected open flux by at least the CME footpoint separation distance. Since the polarity of CME footpoints tends to follow a pattern similar to the Hale cycle of sunspot polarity, repeated CME eruption and subsequent reconnection will naturally result in latitudinal transport of open solar flux. We demonstrate how this process can reverse the coronal and heliospheric fields, and we calculate that the amount of flux involved is sufficient to accomplish the reversal within the 11 years of the solar cycle
Suprathermal plasma observed on STS-3 Mission by plasma diagnostics package
Artificially produced electron beams were used extensively during the past decade as a means of probing the magnetosphere, and more recently as a means of actively controlling spacecraft potential. Experimentation in these areas has proven valuable, yet at times confusing, due to the interaction of the electron beam with the ambient plasma. The OSS-1/STS-3 Mission in March 1982 provided a unique opportunity to study beam-plasma interactions at an altitude of 240 km. On board for this mission was a Fast Pulse Electron Generator (FPEG). Measurements made by the Plasma Diagnostics Package (PDP) while extended on the Orbiter RMS show modifications of the ion and electron energy distributions during electron beam injection. Observations made by charged particle detectors are discussed and related to measurements of Orbiter potential. Several of the PDP instruments, the joint PDP/FPEG experiment, and observations made during electron beam injection are described
Analysis of physical-chemical processes governing SSME internal fluid flows
The efforts to adapt CHAM's computational fluid dynamics code, PHOENICS, to the analysis of flow within the high pressure fuel turbopump (HPFTP) aft-platform seal cavity of the SSME are summarized. In particular, the special purpose PHOENICS satellite and ground station specifically formulated for this application are listed and described, and the preliminary results of the first part two-dimensional analyses are presented and discussed. Planned three-dimensional analyses are also briefly outlined. To further understand the mixing and combustion processes in the SSME fuelside preburners, a single oxygen-hydrogen jet element was investigated
A microgravity isolation mount
The design and preliminary testing of a system for isolating microgravity sensitive payloads from spacecraft vibrational and impulsive disturbances is discussed. The Microgravity Isolation Mount (MGIM) concept consists of a platform which floats almost freely within a limited volume inside the spacecraft, but which is constrained to follow the spacecraft in the long term by means of very weak springs. The springs are realized magnetically and form part of a six degree of freedom active magnetic suspension system. The latter operates without any physical contact between the spacecraft and the platform itself. Power and data transfer is also performed by contactless means. Specifications are given for the expected level of input disturbances and the tolerable level of platform acceleration. The structural configuration of the mount is discussed and the design of the principal elements, i.e., actuators, sensors, control loops and power/data transfer devices are described. Finally, the construction of a hardware model that is being used to verify the predicted performance of the MGIM is described
Enhanced sensitivity to a possible variation of the proton-to-electron mass ratio in ammonia
Numerous accidental near degeneracies exist between the 2ν2 and ν4 rotation-vibration energy levels of ammonia. Transitions between these two states possess significantly enhanced sensitivity to a possible variation of the proton-to-electron mass ratio μ. Using a robust variational approach to determine the mass sensitivity of the energy levels along with accurate experimental values for the energies, sensitivity coefficients have been calculated for over 350 microwave, submillimeter, and far-infrared transitions up to J=15 for 14NH3. The sensitivities are the largest found in ammonia to date. One particular transition, although extremely weak, has a sensitivity of T=−16738 and illustrates the huge enhancement that can occur between close-lying energy levels. More promising however are a set of previously measured transitions with T=−32 to 28. Given the astrophysical importance of ammonia, the sensitivities presented here confirm that 14NH3 can be used exclusively to constrain a spatial or temporal variation of μ. Thus certain systematic errors which affect the ammonia method can be eliminated. For all transitions analyzed we provide frequency data and Einstein A coefficients to guide future laboratory and astronomical observations
A global ab initio dipole moment surface for methyl chloride
A new dipole moment surface (DMS) for methyl chloride has been generated
at the CCSD(T)/aug-cc-pVQZ(+d for Cl) level of theory. To represent the
DMS, a symmetry-adapted analytic representation in terms of nine vibrational
coordinates has been developed and implemented. Variational calculations
of the infrared spectrum of CH3Cl show good agreement with a range
of experimental results. This includes vibrational transition moments, absolute
line intensities of the ν1, ν4, ν5 and 3ν6 bands, and a rotation-vibration
line list for both CH3
35Cl and CH3
37Cl including states up to J = 85 and
vibrational band origins up to 4400 cm−1
. Across the spectrum band shape
and structure are well reproduced and computed absolute line intensities
are comparable with highly accurate experimental measurements for certain
fundamental bands. We thus recommend the DMS for future use.
Keywords: Line-lists, Radiative transfer, Databases, HITRA
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