FEATS - Finite element thermal stress analysis of plane or axisymmetric solids

FEATS computer code uses finite element analysis to calculate steady state temperature and thermal stress fields for either axisymmetric or plane two-dimensional bodies with boundary conditions, including specified displacements, loads, and thermal boundary conditions

Measurement of minority carrier transport parameters in heavily doped n-type silicon

Measurement of minority transport parameters in heavily doped silicon is covered. The basic transport equations were used to define two independent parameters. Use of special vertical and lateral transistor test devices permitted the measurement of both parameters. Prior studies were normalized to show excellent agreement over the heavy doping region

Proximal ecological effects of the 1980 eruptions of Mount St. Helens

The diversity of ecosystems and volcanic processes involved in the 1980 eruptions of Mount St. Helens, southwest Washington, provide an excellent setting for examining effects of volcanic events on ecosystems. These eruptions included a lateral blast, debris avalanche, mudflows, pyroclastic flows, and airfall tephra. Affected ecosystems within 30 km of the vent were lakes, streams, upland and riparian forest, and meadows. Ecological disturbances imposed by the Mount St. Helens events were predominantly physical, rather than climatic or chemical which are the dominant classes of disturbances considered in analysis of global catastrophes. Analysis of ecosystem response to disturbance should be based on consideration of composition and structure of the predisturbance system in terms that represent potential survivability of organisms, mechanisms in the primary disturbance, initial survivors, secondary disturbances arising from the primary disturbance and the biological responses to secondary disturbances, invasion of the site by new propagules, interactions among secondary disturbance processes and surviving and invading organisms. Predicting ecosystem response to disturbance is enchanced by considering the mechanisms of disturbance rather than type of disturbance. In the 1980 Mount St. Helens events, the disturbance types, involved primarily the mechanisms of sedimentation, heating, and shear stress. Each disturbance type involved one or more mechanisms. Ecosystem response varied greatly across the landscape. Analysis of ecosystem response to disturbance, regardless of type, should include detailed consideration of the properties of individual species, primary and secondary disturbance mechanisms, and their distributions across landscapes

The stability of an air-maintained cavity behind a stationary object in flowing water

In studies made in the Free Surface Water Tunnel of a projectile running in an air-maintained cavity, the experimental relation between air entrainment rate and cavitation number was determined. The entrainment-rate coefficient CQ = Q/V0d^2, where Q is the air rate in cfs, V0 the free-stream velocity, and d the disk nose diameter, was plotted against cavitation parameter, K = (p0 - pk)/q0 where p0 is the free-stream pressure at the disk center line, pk the cavity pressure, and q0 the free-stream dynamic pressure. This experimental relationship for one single disc is shown for three different velocities in Fig. 1. The curves are similar in shape and each has a minimum value of entrainment coefficient which is designated by CQ^* at a value of K as designated as K^*

Estimating the stochastic uncertainty in sample-based estimates of infant mortality in Ghana

The Infant Mortality Rate (IMR) is an important population health statistic often used as one of the indicators of the health status of a nation. In many countries lacking adequate vital registration systems, sample methods are used to estimate IMRs. However, evaluations of this approach are rare and the literature contains no assessments of the stochastic uncertainty underlying these estimated IMRs. Stochastic uncertainty reflects the fact that even where the underlying IMR is constant in a small population over time, there is a likelihood of yearly fluctuation in its empirical observations even if it is measured from a complete count of the events of interest. In this study a method is presented that can be used to assess this stochastic uncertainty. We use the country of Ghana as a case study for this purpose. The method, a beta-binomial model, is described, tested for validity, and illustrated using 2014 sample-based estimates of IMR for 13 sample regions in Ghana. As such, the approach we described regarding the revision of sample-based IMR estimates is aimed at taking into account of the stochastic uncertainty while preserving the information concerning the uncertainty due to sampling. In applying the method to Ghana, we find that the sample-based IMR estimates perform well in accounting for stochastic uncertainty and could be applied elsewhere

On the decode error probability for Reed-Solomon codes

Upper bounds on the decoder error probability for Reed-Solomon codes are derived. By definition, decoder error occurs when the decoder finds a codeword other than the transmitted codeword; this is in contrast to decoder failure, which occurs when the decoder fails to find any codeword at all. The results imply, for example, that for a t error correcting Reed-Solomon code of length q - 1 over GF(q), if more than t errors occur, the probability of decoder error is less than 1/t! In particular, for the Voyager Reed-Solomon code, the probability of decoder error given a word error is smaller than 3 x 10 to the minus 14th power. Thus, in a typical operating region with probability 100,000 of word error, the probability of undetected word error is about 10 to the minus 14th power

Node Synchronization for the Viterbi Decoder

Motivated by the needs of NASA's Voyager 2 mission, in this paper we describe an algorithm which detects and corrects losses of node synchronization in convolutionally encoded data. This algorithm, which would be implemented as a hardware device external to a Viterbi decoder, makes statistical decisions about node synch based on the hard-quantized undecoded data stream. We will show that in a worst-case Voyager environment, our method will detect and correct a true loss of synch (thought to be a very rare event) within several hundred bits; many of the resulting outages will be corrected by the outer Reed-Solomon code. At the same time, the mean time between false alarms is on the order of several years, independent of the signal-to-noise ratio

General series solution technique for bending of irregular laterally loaded flat plates

Computer program calculates the stresses and lateral deflections to a uniform thickness flat plate with a uniform pressure load. The plate to be analyzed may have several different boundary conditions. The program is written in FORTRAN 4 for use on the CDC 6600 computer

Extreme temperature requirements for spacecraft electronics parts FY 1971 the orbiter case

Determining temperature extremes in electronic components of spacecraft on interplanetary orbiter and flyby mission

Millimeter radiometer system technology

JPL has had a large amount of experience with spaceborne microwave/millimeter wave radiometers for remote sensing. All of the instruments use filled aperture antenna systems from 5 cm diameter for the microwave Sounder Units (MSU), 16 m for the microwave limb sounder (MLS) to 20 m for the large deployable reflector (LDR). The advantages of filled aperture antenna systems are presented. The requirements of the 10 m Geoplat antenna system, 10 m multified antenna, and the MLS are briefly discussed