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Here, we report novel empirical results from a psychophysical experiment in which we tested the echolocation abilities of nine blind adult human experts in click-based echolocation. We found that they had better acuity in localizing a target and used lower intensity emissions (i.e., mouth clicks) when a target was placed 45° off to the side compared with when it was placed at 0° (straight ahead). We provide a possible explanation of the behavioral result in terms of binaural-intensity signals, which appear to change more rapidly around 45°. The finding that echolocators have better echo-localization off axis is surprising, because for human source localization (i.e., regular spatial hearing), it is well known that performance is best when targets are straight ahead (0°) and decreases as targets move farther to the side. This may suggest that human echolocation and source hearing rely on different acoustic cues and that human spatial hearing has more facets than previously thought.

Lodging is a major constraint to increasing the global productivity of maize (Zea Maize L.). The objectives of this paper are to: i) describe a model for stem and root lodging in maize, ii) calibrate the anchorage strength component of the model, iii) evaluate the model's applicability by assessing its capacity to explain effects of crop husbandry on lodging risk and iv) investigate the potential to further develop the lodging model to predict lodging risk at an early enough growth stage for tactical agronomic action to minimise lodging risk. The study involved a multidisciplinary collaboration between crop scientists, wind engineers and geospatial scientists in the UK and China. Three field experiments with plant population density and nitrogen (N) fertiliser rate treatments were conducted in the UK and China to develop and test the lodging model. Plant characteristics associated with lodging were measured in the experiments after flowering. An existing model of cereal anchorage strength that uses the spread of the root plate as its primary input was demonstrated to be applicable for maize and calibrated for this crop species. The lodging model's predictions of the effects of plant population and N fertiliser on lodging risk were consistent with published observations. The lodging model calculated that increasing the plant population significantly reduced the anchorage and stem failure wind speeds in all experiments, thus increasing the risk of lodging. This effect was primarily due to increased plant population reducing the spread of the root plate and the stem strength. Changes in N fertiliser had a smaller effect on the lodging associated plant characters. A sensitivity analysis showed that stem failure wind speed was influenced most by variation in stem strength and root failure wind speed was influenced most by variation in the spread of the root plate. This study has shown that the leaf area index measured at leaf 4, 6 or 8 stages is a good indicator of a cro

This paper considers a process through which the wind costs the agricultural industry hundreds of millions of pounds per year - crop lodging. Lodging is the displacement of crops by wind (and rain) that can result in either stem breakage or uprooting. In particular this paper builds upon recent work to develop a generalised model of the lodging process and presents the results of several experimental campaigns to identify dynamic and aerodynamic parameters that are required as inputs to the model in order to estimate lodging wind speeds. These experiments were carried out at various sites in the UK and the Republic of Ireland to determine the natural frequencies, damping ratios and drag areas of maize, oats and oil seed rape. The experimental methodology, which was based upon the tracking of plant displacements, was shown to be robust, and consistent values of the parameters were obtained, albeit with much larger experimental uncertainties than would normally be expected in wind engineering applications. The values of these parameters were also consistent with those of earlier measurements for wheat. The generalised model was then used to determine lodging wind speeds for the three crops, and an assessment was made of the effect of experimental uncertainties in dynamic, aerodynamic and agronomic variables on the predicted values. In broad terms the generalised lodging model was shown to well describe the crop behaviour for isolated crops, and it was shown that it could be used in a simplified form for interlocked crop canopies. It was also shown that uncertainties in the aerodynamic parameters resulted in uncertainties of around an order of magnitude in lodging risk, whilst typical variations between plants in some crop parameters (notably stem strength and radius) could result in lodging risk uncertainties of two orders of magnitude.

© 2020 Elsevier B.V. To prevent possible freeze out in the main cryogenic heat exchanger (MCHE) used in liquefied natural gas (LNG) plants, new and accurate phase equilibrium data are required to improve the predictive reliability of existing models, in particular cubic equations of state (EOS). In this work, the vapor-liquid equilibrium (VLE) of a ternary methane + propane + toluene (methylbenzene) mixture was studied over a wide range of conditions with toluene as the minor component in both the liquid and vapor phases. Measurements were conducted along different isochoric paths at temperatures between (213 and 298 K) and pressures up to 8.3 MPa, to obtain data at conditions relevant to the operation of LNG scrub columns. The measured VLE data were compared to results calculated with the HYSYS Peng Robinson (PR) equation of state (EOS) that is used widely in LNG industry. The amount of toluene in the vapor phase was found to be under-predicted by the HYSYS PR EOS by an average of around 77% at lower temperatures, with the error increasing as temperature and toluene concentration decreased. The current work demonstrates that the HYSYS PR EOS as well as other cubic EOS substantially under-predict the possible toluene content of saturated vapours that could be present in the overhead of the LNG scrub column. Using the ThermoFAST model recently developed and optimised for the calculation of solid-liquid equilibrium conditions in LNG production, this work further demonstrates that the 77% increase in the toluene content of a saturated vapor entering the MCHE, corresponds to a 7 K increase in the solid formation temperature, which could significantly increase the likelihood of a blockage in the MCHE and thus possible shutdown of the LNG plant. The experimental and modelling work presented here underscores the importance of improving predictions of the allowable threshold concentration of heavy components in fluids entering cryogenic heat exchangers in LNG plants.