Effect of molecular relaxation processes on travelling wave solutions of sonic boom waveforms

Asymptotic and numerical analyses are presented for the travelling wave solution of the one-dimensional acoustic wave associated with the sonic boom, subject to thermoviscous dissipation and two molecular relaxation processes. Examination of how these relaxation processes affect the propagation of a weak shock is discussed in detail

Investigation of stratiform sulphide mineralisation at Meall Mor, South Knapdale, Argyll

A co-ordinated geochemical-geophysical-geological investigation of copper mineralisation in the Meal1 ?46r area, South Knapdale, Argyll was carried 0th in 1976 and followed by a drilling programme of 3 shallow holes in early 1977. The mineralisation occursin a zone of weak stratiform sulphide mineralisation (the pyrite zone) with a strike length of 1Okm in the Upper &ins Quartz&e of the Middle Dalradian. The geochemical drainage survey showed the existence of a strongly anomalous distribution of Cu and Sb in the Abhainn Srathain draining south from . Meal1 M&- and detailed soil sampling over the pyrite zone outlined a broad area enriched in copper. Deeper soil sampling confirmed the anomalously high copper values and a coincident IP anomaly was found stretching from Meal1 M& south to the old mine workings on Abhainn Srathain, and is probably caused by a local enrichment of pyrite and chalcopyrite within the pyrite zone. Three boreholes were drilled; two on coincident geochemical and geophysical anomalies, and the third beneath the old mines at Abhainn Srathain. Copper values in the first two holes range up to 0.24% Cu over 4.27m, but up to 1.06% Cu over 2.67m in the third and this enrichment may be related to a later remobilisation of the disseminated chalcopyrite. The results of subsequent drilling at two other sites are given in Appendix III

A Renormalization-Group approach to the Coulomb Gap

The free energy of the Coulomb Gap problem is expanded as a set of Feynman diagrams, using the standard diagrammatic methods of perturbation theory. The gap in the one-particle density of states due to long-ranged interactions corresponds to a renormalization of the two-point vertex function. By collecting the leading order logarithmic corrections we have derived the standard result for the density of states in the critical dimension, d=1. This method, which is shown to be identical to the approach of Thouless, Anderson and Palmer to spin glasses, allows us to derive the strong-disorder behaviour of the density of states. The use of the renormalization group allows this derivation to be extended to all disorders, and the use of an epsilon-expansion allows the method to be extended to d=2 and d=3. We speculate that the renormalization group equations can also be derived diagrammatically, allowing a simple derivation of the crossover behaviour observed in the case of weak disorder.Comment: 16 pages, LaTeX. Diagrams available on request from [email protected]. Changes to figure 4 and second half of section

Pre-emergence tillage in field pea effective, but timing critical

Non-Peer ReviewedOn the semi-arid prairies, it is generally recommended to seed field pea early and at a depth of 4 to 7.5 cm. Crops that emerge before weed emergence are more competitive than crops emerging at the same time or after weed emergence. Delayed seeding to control late-emerging weeds and seeding at shallower depths to promote rapid emergence may be an alternative weed management strategy. The objective of this experiment was to identify combinations of seed date, seed depth, and pre-emergent weed control to optimize yield of field pea grown without the use of herbicides

The form and auditory control of downward trends in intonation

Of all the areas of intonational research, study of the tendency of the frequency of vocal fold vibration to decline during the course of an utterance - F0 declination - is likely initially to be the most fruitful in determining the interaction between perceptual and productive processes. A general introduction to the phenomenon is augmented by analysis of different methods of determining declination lines; theoretical treatments are then introduced. One particular local factor contributing to the downward trend, downstep, is discussed, and its pivotal role in the intonational phonology developed by Janet Pierrehumbert critically examined. In the light of the theoretical discussion, two competing hypotheses are presented as to the mediation of the declination effect, which is the effect that of two accented syllables in an utterance, the second has to have a lower peak F0 value than the first for them to be judged to have equal prominence. The Global Declination Hypothesis attributes this to the use by speakers and hearers of one or two abstract reference lines declining through the course of a tone-unit. The Local Declination Hypothesis attributes it to the disposition of F0 excursions surrounding the two accents as well as to the respective peak values. The Global Declination Hypothesis is tested by presenting listeners with pairs of dual-peak accented utterances with the two peaks identical in F0, without any physically present local declination, and asking them to rate the prominence of the second peak of each such utterance. No significant differences are found in the prominence ratings, so the Local Declination Hypothesis appears to be favoured. That hypothesis is itself tested through the development of a model of individual accent prominence, which incorporates terms for surrounding unaccented context. This is then used as the basis of a model of the perceptual constraints on the production of intonation in the scaling of target peaks. The model predicts that local slope between accents and slope of the context after the target accent, as well as other local variables, jointly determine the F0 value of a peak with a particular targetted prominence relationship with its predecessor. If the interaccentual stretch is declining, the declination effect is predicted to occur, ceteris paribus. The model is found to be initially acceptable. In addition, a global interpretation of downstep is made within the model. The mechanisms the model is suggested to represent are auditory feedback control loops of a variety of possible degrees of complexity. An experiment is devised to test for the basic existence of a feedback loop which is used to prevent local slope exceeding an arbitrary threshold value. Auditory feedback In subjects was disrupted by headphone-administration of low-pass filtered masking noise during their utterance of a sustained vowel, and a short and a long dual peak-accented sentence. The disruption was sufficient to alter the apparent mechanism controlling the production of the sustained vowel, but the Lombard effect, whereby subjects automatically raise the level of their voice in ambient noise, was found to be a vitiating factor. General conclusions are drawn on the nature of the declination phenomenon In intonation, and proposals made for future research

Building an Improved Drought Climatology Using Updated Drought Tools: A New Mexico Food-Energy-Water (FEW) Systems Focus

Drought is a familiar climatic phenomenon in the United States Southwest, with complex human-environment interactions that extend beyond just the physical drought events. Due to continued climate variability and change, droughts are expected to become more frequent and/or severe in the future. Decision-makers are charged with mitigating and adapting to these more extreme conditions and to do that they need to understand the specific impacts drought has on regional and local scales, and how these impacts compare to historical conditions. Tremendous progress in drought monitoring strategies has occurred over the past several decades, with more tools providing greater spatial and temporal resolutions for a variety of variables, including drought impacts. Many of these updated tools can be used to develop improved drought climatologies for decision-makers to use in their drought risk management actions. In support of a Food-Energy-Water (FEW) systems study for New Mexico, this article explores the use of updated drought monitoring tools to analyze data and develop a more holistic drought climatology applicable for New Mexico. Based upon the drought climatology, droughts appear to be occurring with greater frequency and magnitude over the last two decades. This improved drought climatology information, using New Mexico as the example, increases the understanding of the effects of drought on the FEW systems, allowing for better management of current and future drought events and associated impacts

On the Neutrality of Flowshop Scheduling Fitness Landscapes

Solving efficiently complex problems using metaheuristics, and in particular local searches, requires incorporating knowledge about the problem to solve. In this paper, the permutation flowshop problem is studied. It is well known that in such problems, several solutions may have the same fitness value. As this neutrality property is an important one, it should be taken into account during the design of optimization methods. Then in the context of the permutation flowshop, a deep landscape analysis focused on the neutrality property is driven and propositions on the way to use this neutrality to guide efficiently the search are given.Comment: Learning and Intelligent OptimizatioN Conference (LION 5), Rome : Italy (2011

The critical Ising model via Kac-Ward matrices

The Kac-Ward formula allows to compute the Ising partition function on any finite graph G from the determinant of 2^{2g} matrices, where g is the genus of a surface in which G embeds. We show that in the case of isoradially embedded graphs with critical weights, these determinants have quite remarkable properties. First of all, they satisfy some generalized Kramers-Wannier duality: there is an explicit equality relating the determinants associated to a graph and to its dual graph. Also, they are proportional to the determinants of the discrete critical Laplacians on the graph G, exactly when the genus g is zero or one. Finally, they share several formal properties with the Ray-Singer \bar\partial-torsions of the Riemann surface in which G embeds.Comment: 30 pages, 10 figures; added section 4.4 in version

Radiation induced oscillatory Hall effect in high mobility GaAs/AlGaAs devices

We examine the radiation induced modification of the Hall effect in high mobility GaAs/AlGaAs devices that exhibit vanishing resistance under microwave excitation. The modification in the Hall effect upon irradiation is characterized by (a) a small reduction in the slope of the Hall resistance curve with respect to the dark value, (b) a periodic reduction in the magnitude of the Hall resistance, $R_{xy}$, that correlates with an increase in the diagonal resistance, $R_{xx}$, and (c) a Hall resistance correction that disappears as the diagonal resistance vanishes.Comment: 4 pages text, 4 color figure