The variational theory of complex rays for the calculation of medium-frequency vibrations

A new approach called the ``variational theory of complex rays’’ (VTCR) is developed for calculating the vibrations of weakly damped elastic structures in the medium-frequency range. Here, the emphasis is put on the most fundamental aspects. The effective quantities (elastic energy, vibration intensity, etc.) are evaluated after solving a small system of equations which does not derive from a finite element discretization of the structure. Numerical examples related to plates show the appeal and the possibilities of the VTCR

The status of the word-final domain and linguistically-constrained language learning cues

Past experimental and theoretical research have argued that phonological devoicing as a word-final phenomenon only has inherent phonetic motivation to exist utterance-finally and that its presence at lower domain levels is due to analogy (Hock 1991, 1999; Hualde and Eager 2016). This evinces the idea that the word is not a domain tied to phonology inherently. Juxtaposingly, final devoicing (FD) is found phonetically at various prosodic domain levels. Final lengthening (FL) is also found at various prosodic levels, though is explained as only having a push to exist utterance-finally through a process similar to the “slowing down of a machine” or “tempo change...local to the final gesture in the phrase” (Klatt 1976 and Edwards et al. 1991 respectively). The present artificial language learning (ALL) experiment gives evidence that these cues may have an inherent reason for existing at lower domain levels. Participants were exposed to 7 minutes of AL stimulus in one of three conditions: transitional probabilities (TP) or the likelihood that syllables will occur in sequence together, final lengthening (FL) or greater duration of final segments, and final devoicing (FD) or a trailing off of voicing in word-final segments. They were then tested on their ability to segment the AL words out of the speech stream. The results show there is a perceptual effect to having phonetic FL at the right edge of words for listeners, in that it increases novel word segmentation ability above the level of only TPs. The same effect was not found for FD. The FL results indicate that phenomena in the word-final area may be used for perceptual reasons, providing evidence speakers use phonetic effects at the word-level

Mining for a Reference Condition in Southern West Virginia Streams

Quarterly samples were used to estimate assemblage-level (all species combined) fish production within three minimally-impacted, southern West Virginia streams. The total annual fish production estimate was highest in Slaunch Fork (37.52 kg∙ha-1∙y-1), a tributary of the Tug Fork River, and lowest in Cabin Creek (10.59 kg∙ha-1∙y-1), a Guyandotte River tributary. Creek Chub Semotilus atromaculatus, Mottled Sculpin Cottus bairdii and Blacknose Dace Rhinicthys atratulus were the most abundant species among sites, accounting for \u3e90% of all sampled individuals. Reference condition criteria were also selected and metrics calculated for each of the three stream sites using a variety of established metrics. According to established criteria, all three of our sites scored high enough to be listed as “reference” sites. Third, a comprehensive GIS analysis was conducted in order to determine land use patterns and predict where similar assemblages would be present using various climatological and physical characteristics of our stream sites. These analyses revealed rapid expansion of surface mining activities putting many stream systems at risk

Long-life mission reliability for outer planet atmospheric entry probes

The results of a literature analysis on the effects of prolonged exposure to deep space environment on the properties of outer planet atmospheric entry probe components are presented. Materials considered included elastomers and plastics, pyrotechnic devices, thermal control components, metal springs and electronic components. The rates of degradation of each component were determined and extrapolation techniques were used to predict the effects of exposure for up to eight years to deep space. Pyrotechnic devices were aged under accelerated conditions to an equivalent of eight years in space and functionally tested. Results of the literature analysis of the selected components and testing of the devices indicated that no severe degradation should be expected during an eight year space mission