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AbstractIf the energy‐density of prey bodies is not uniform, predators usually should maximize their rate of energy intake while foraging by selectively consuming energy‐rich regions of their prey and discarding other parts. In this study, the hypothesis of selective body‐part consumption was tested using two species of dasyurid marsupials, Sminthopsis youngsoni and Ningaui ridei, and their invertebrate prey in arid central Australia. Energy‐densities were similar for several divergent types of prey, including whole insects, centipedes, and spiders (20.2 ± 2.19 (sd) J/mg ash‐free dry mass), but there were marked differences in energy‐density among orders of insects and also between different body regions of invertebrates. In captivity, the two dasyurid species consumed different body regions of prey in the same way. For beetles and cockroaches, the rank order for selection of body parts was abdomen, thorax, head, then legs; for centipedes it was body, then head + legs; and for spiders it was opisthosoma, prosoma and then legs. Selection of prey body regions by the marsupials correlated closely with the energy‐densities of these regions, and also with the rates of energy intake that they yielded. In the field, selection of body parts of arthropod prey by dasyurids probably occurs primarily when prey is abundant. This selection should allow maximization of rates of energy intake in favourable periods and should, in turn, allow dasyurid predators to effectively exploit pulses of prey resources in the temporally variable desert environment.

Abstract The penetration level of residential battery energy storage systems (BESSs) has been increasing in recent years. However, it is still not clear how they would impact the hosting capacity of a network. This paper presents an optimization-based framework to assess the impact of BESSs and network tariffs on the minimum photovoltaic hosting capacity (MPVHC) of distribution systems. The paper considers a rule-based as well as a mixed-integer linear programming (MILP)-based home energy management schemes to schedule the BESSs. The performance of the proposed method is compared with that of the Monte Carlo approach. It is shown that the proposed method identifies a considerably more accurate result than Monte Carlo approach. Then, the proposed methodology is applied to 128 real low voltage feeders in the U.K. The simulation results show that the effectiveness of BESSs in increasing the MPVHC depends on the penetration of BESSs in the system and the scheduling scheme of BESSs. Further, the MPVHC increases more in the cost minimization scheme compared to the self-consumption minimization. Finally, it is shown that both flat and Time-of-Use tariffs have a similar effect on the MPVHC.

Abstract Very deep coal seams which are unlikely to be mined may be considered for CO 2 sequestration. The main objective of this study is to investigate the effect of temperature on the permeability of naturally fractured coal. Permeability tests were conducted on naturally fractured bituminous coal samples using high pressure triaxial equipment for five different injecting pressures (8–13 MPa) under two different confinements (20 and 24 MPa) and five different temperatures (25–70 °C). The experimental data were then used to develop an appropriate numerical model using the COMET 3 simulator to model the temperature effect on permeability at temperatures up to 200 °C. According to the measured permeability values and the developed lab-scale model, there is a clear increase in CO 2 permeability with increasing temperature for any confining pressure at high injecting pressures (more then 10 MPa). However, for low injecting pressures (less than 9 MPa) temperature effect is not so much. With increasing injecting pressure, CO 2 permeability decreases at low temperatures (less than around 40 °C), and increases at high temperatures (more than 50 °C). Interestingly, the temperature effect on permeability is significant only up to around 90 °C condition within the 25–200 °C temperature limit. These observations are related with the sorption behavior of the adsorbing CO 2 during the injection. However, there is no noticeable temperature effect on N 2 permeability as it does not create any swelling effect in coal matrix.

Abstract Computational fluid dynamics (CFD) has been used to study fully developed laminar flow and heat transfer behaviour in periodic trapezoidal channels with a semi-circular cross-section. The trapezoidal elements are characterised by their wavelength (2L), channel diameter (d), radius of curvature of bends (Rc), the amplitude (2A) and the length of the straight section (B) with results reported for Reynolds numbers (Re) up to 400, as well as for a range of geometric configurations ( 0.525 ⩽ R c d ⩽ 1.3 , 3.6 ⩽ L d ⩽ 12 , 0.17 ⩽ B L ⩽ 1 , 0.125 ⩽ A L ⩽ 1 ) at Re = 200. This generic geometry takes a variety of shapes with limiting forms of a regular square serpentine (B = 2A = L) and a zig-zag or saw-tooth (B → 0). The flow in these channels is characterised by the formation of Dean vortices following each bend. As the Reynolds number is increased, stronger vortical flow patterns emerge and these vortices lead to efficient fluid mixing and high rates of heat transfer. Constant wall heat flux (H2), constant axial heat flux with peripherally constant temperature (H1) and constant wall temperature (T) boundary conditions are examined for a fluid with a Prandtl number of 6.13. Higher rates of heat transfer with relatively small pressure loss penalty are found relative to fully developed flow in a straight pipe, with heat transfer enhancements of up to four at the highest Reynolds number. In addition to presenting channel enhancements the stackability of channels on a plate is considered. The concepts of area enhancement (based solely on geometric factors) and heat transfer intensification, the product of the heat transfer enhancement and the area enhancement, are introduced and used to compare different geometrical configurations. The swept zig-zag pathway provided the greatest intensification of heat transfer in a multi-channel plate structure.

Abstract Periodically adjusted parabolic mirror/evacuated tube absorber combinations are evaluated using computer simulation methods. The results show that a 4–6 X reflector adjusted 10–15 times per year, operating at 150°C, competes favourably in cost-effective terms with a fixed reflector CPC collector operating at 50°C. Periodically adjusted collectors are advocated for medium temperature industrial applications below 200°C.

In the current era, the importance of proper hand hygiene to reduce the transmission of infectious diseases has become difficult to debate. Yet, compliance rates remain low and are affected by many factors, amongst which is user acceptability of hand hygiene products.The present study aimed at investigating drivers of preference towards different hand hygiene formulations.Three different formulations (liquid, foam and gel) of the same brand were randomly and blindly evaluated by 54 participants based on the WHO Protocol for Evaluation of Tolerability and Acceptability of Alcohol-based Handrubs.The majority (76%) of respondents indicated that the product formulation impacted their level of compliance with hand hygiene protocols. The preferred formulation was liquid, with 50% of participants ranking it as first choice. General product satisfaction, the product texture, the drying speed and the ease of application, were the statistically significant drivers for participants to rank a formulation as their first choice vs not ranking it as their first choice.When designing alcohol formulations and implementing hand hygiene protocols, understanding drivers of preference for formulations may enhance product user acceptability and therefore compliance with hand hygiene.

Abstract Maximally concentrating collectors include the class of ideal concentrating collectors, but are a more general class offering many more practical possibilities. By evaluating such configurations using the concept of maximal flux concentration, based upon average radiation flux concentration over the acceptance angle, clear ray trace comparisons may be made between different collector configurations. These comparisons allow the most effective configuration to be selected for a given application. An example of a comparatively simple and practical two-stage concentrator having equal or better maximal performance than previous work for high rim angle primaries is given. This uses an unusual straight section of reflector and allows rays to cross from one reflector segment of the secondary to another. Versions which allow concentration up to 90% of maximal are described, as are versions achieving 80% with high collection efficiency. Use of the 1 sin θ max geometrical concentration criterion based upon aperture ratios is suggested to be inappropriate for comparisons.

Abstract The paper is focusing on a shell and plate heat exchanger of a novel absorption refrigeration system. The system is composed of two vacuum vessels connected together with a steam channel and one heat exchanger is located in each vessel. The first heat exchanger is called reactor where working fluid and salt exist and the second heat exchanger or evaporator/condenser (C/E) is where only water exists. The propylene glycol-based (PG) heat transfer fluid is used on the shell side of both heat exchangers as the media to exchange the heat between boilers and reactor in one vessel and between cold environment and condenser/evaporator in another vessel. An experimental test rig was built to investigate the performance of the evaporator/condenser heat exchanger. Then, a three-dimensional (3D) Computational Fluid Dynamics (CFD) model was developed. The experimental result was then used to validate the numerical model developed by using Ansys/Fluent software. A parametric study has been intended to find a more appropriate design for the heat exchanger in order to increase heat transfer performance. Results of the parametric study demonstrated that the cooling performance is doubled by increasing the diameter of the plate from 0.14 m to 0.2 m. In addition, to obtain the maximum heat transfer performance, Reynolds number and distance between plates should be 9 and 0.5 m, respectively. Two correlations have been developed for the outlet temperature and cooling power of the heat exchanger which are functions of heat transfer coefficient. The results of this study can be of vital importance for improving the cooling power of the system, remarkably.