A latitude comparison of N2 density measurements by mass spectrometer

Latitude comparison of N2 ion density measurement by experimental mass spectromete

The Spectrum of GRB 930131 (``Superbowl Burst'') from 20 keV to 200 MeV

We have constructed a broad-band spectrum for GRB 930131 (the ``Superbowl Burst''), ranging from 20 keV to 200 MeV, by combining spectral information from the Gamma Ray Observatory's BATSE, COMPTEL and EGRET instruments. We present general methods for combining spectra from different time intervals obtained by the same instrument as well as for combining spectra from the same time interval taken by different instruments. The resulting spectrum is remarkably flat (in nu F_nu-space) up to high energies. We find that the spectral shape can be successfully fitted by the shocked synchrotron emission model of Tavani. We present evidence that the flatness of the spectrum at high energies is not due to spectral time-variability.Comment: ApJ accepted, 10 pages, 1 table, 3 figure

Aerodynamic and acoustic performance of a contracting cowl high throat Mach number inlet installed on NASA quiet engine C

The approach and takeoff performance was evaluated of a contracting cowl variable geometry design inlet installed on a high-bypass-ratio turbofan engine. The design was finalized after consideration of aerodynamic, acoustic, and mechanical factors which would lead to a viable flight worthy concept. The aerodynamic results are presented in terms of inlet recovery and distortion parameter as functions of throat Mach number, and acoustic results in terms of Perceived Noise Level. The contracting cowl high throat Mach number inlet is shown to be an attractive means to reduce forward radiated noise from a high bypass ratio turbofan engine

Aero-acoustic performance comparison of core engine noise suppressors on NASA quiet engine C

The relative aero-acoustic effectiveness of two core engine suppressors, a contractor-designed suppressor delivered with the Quiet Engine, and a NASA-designed suppressor was evaluated. The NASA suppressor was tested with and without a splitter making a total of three configurations being reported in addition to the baseline hardwall case. The aerodynamic results are presented in terms of tailpipe pressure loss, corrected net thrust, and corrected specific fuel consumption as functions of engine power setting. The acoustic results are divided into duct and far-field acoustic data. The NASA-designed core suppressor did the better job of suppressing aft end noise, but the splitter associated with it caused a significant engine performance penality. The NASA core suppressor without the spltter suppressed most of the core noise without any engine performance penalty

Development of optical coatings for cos thin film solar cells third quarterly report, jun. 1 - aug. 1, 1965

Sputtering of glass coatings on cadmium sulfide thin film solar cell

Development of optical coatings for cds thin film solar cells second quarterly report, 1 mar. - 1 jun. 1965

Optical coatings for cadmium sulfide thin film solar cell

Vacuum fluctuations and the thermodynamics of chiral models

We consider the thermodynamics of chiral models in the mean-field approximation and discuss the relevance of the (frequently omitted) fermion vacuum loop. Within the chiral quark-meson model and its Polyakov loop extended version, we show that the fermion vacuum fluctuations can change the order of the phase transition in the chiral limit and strongly influence physical observables. We compute the temperature-dependent effective potential and baryon number susceptibilities in these models, with and without the vacuum term, and explore the cutoff and the pion mass dependence of the susceptibilities. Finally, in the renormalized model the divergent vacuum contribution is removed using the dimensional regularization.Comment: 9 pages, 5 figure

Acoustic performance of inlet multiple-pure-tone suppressors installed on NASA quiet engine C

The length of multiple-pure-tone (MPT) treatment required to reasonably suppress the MPT's produced by a supersonic tip speed fan was defined. Other suppression, broadband, and blade passing frequency, which might be accomplished were also determined. The experimental results are presented in terms of both far-field and duct acoustic data

A feasibility study of wearable activity monitors for pre-adolescent school-age children.

IntroductionUnderstanding physical activity is key in the fight against childhood obesity. The objective of this study was to examine the feasibility of using certain wearable devices to measure physical activity among children.MethodsA qualitative study was conducted with 25 children aged 7 to 10 years to assess acceptability and compliance of wearable activity devices in this age group. During March through August 2012, children participated in a 4-week study of 3 accelerometer models and a heart rate monitor. Children were asked to use a different device each week for 7 consecutive days. Children and their parents completed structured interviews after using each device; they also completed a final exit interview.ResultsThe wrist-worn Polar Active was the device most preferred by children and was associated with the highest level of compliance. Devices that are comfortable to wear, fit properly, have engaging features, and are waterproof increase feasibility and are associated with higher levels of compliance.ConclusionThe wrist-worn device was the most feasible for measuring physical activity among children aged 7 to 10 years. These findings will inform researchers in selecting tools for measuring children's physical activity

Noise generated by quiet engine fans. 2: Fan A

A significant effort within the NASA Quiet Engine Program has been devoted to acoustical evaluation at the Lewis Research Center noise test facility of a family of full-scale fans. This report, documents the noise results obtained with fan A - a 1.5-pressure-ratio, 1160-ft/sec-tip-speed fan. The fan is described and some aerodynamic operating data are given. Far-field noise around the fan was measured for a variety of configurations pertaining to acoustical treatment and over a range of operating conditions. Complete results of 1/3-octave band analysis of the data are presented in tabular form. Included also are power spectra and sideline perceived noise levels. Some representative 1/3-octave band data are presented graphically, and sample graphs of continuous narrow-band spectra are also provided