The benefits of planar circular mouths on suction feeding performance

Suction feeding is the most common form of prey capture across aquatic feeding vertebrates and many adaptations that enhance efficiency and performance are expected. Many suction feeders have mechanisms that allow the mouth to form a planar and near-circular opening that is believed to have beneficial hydrodynamic effects. We explore the effects of the flattened and circular mouth opening through computational fluid dynamics simulations that allow comparisons with other mouth profiles. Compared to mouths with lateral notches, we find that the planar mouth opening results in higher flow rates into the mouth and a region of highest flow that is positioned at the centre of the mouth aperture. Planar mouths provide not only for better total fluid flow rates through the mouth but also through the centre of the mouth near where suction feeders position their prey. Circular mouths are shown to provide the quickest capture times for spherical and elliptical prey because they expose the prey item to a large region of high flow. Planar and circular mouths result in higher flow velocities with peak flow located at the centre of the mouth opening and they maximize the capacity of the suction feeders to exert hydrodynamic forces on the prey.     

The role of the methyl ester moiety in biodiesel combustion: A kinetic modeling comparison of methyl butanoate and n-butane

Growth of the biodiesel industry has motivated increased study of the combustion characteristics of its constituent molecules and building combustion modeling capability. Understanding how these characteristics differ between bio-derived and conventional diesel fuels can help in evaluating biodiesel performance. A kinetic modeling comparison of methyl butanoate and n-butane, its corresponding alkane, contrasted the combustion of methyl esters and normal alkanes, towards understanding the effect of the methyl ester moiety. Utilizing a combined n-heptane and methyl butanoate kinetic mechanism in shock tube simulations, the results predicted no region of negative temperature coefficient (NTC) behavior for methyl butanoate, compared to a well defined NTC region for n-butane. We observed that oxidation pathways associated with the methyl ester moiety inhibited NTC behavior, through increased production of hydroperoxy radicals (HO₂) instead of hydroxyl radicals (OH). In addition, we compared the evolution of carbon monoxide, carbon dioxide, ethylene and acetylene. The early formation of CO and CO₂, directly from methyl butanoate, revealed unique reaction pathways that also influenced a reduction in soot precursor formation. Overall, these results will help to understand how combustion processes change with the inclusion of oxygenated fuels, which will inform the study and design of combustion technologies.     

Development of an Active Thermoplastic Film with Oxygen Scavengers Made of Activated Carbon and Sodium Erythorbate

An active thermoplastic film made of low‐density polyethylene (LDPE) filled with oxygen scavengers made of powdered activated carbon (PAC) impregnated with sodium erythorbate (SE) was developed for packaging applications. Initial tests indicated that the impregnation of PAC with SE enhanced the heat resistance of SE, thereby allowing processing at temperatures typical of LDPE manufacturing. Subsequently, LDPE films with PAC/SE particles were manufactured in coupons that represented a typical juice package, and experiments indicated that these films absorbed 3.57 mg of oxygen in 11 days. This amount corresponded to 80% the concentration of oxygen in the headspace of the package. Furthermore, findings indicated that active particles alone have 10 times higher oxygen absorption capacity than the active LDPE film. Finally, the physical properties of the film were characterized by microscopy where oxygen scavengers showed a good dispersion within the matrix. However, 20 wt.% of these active particles decreased tensile strength of the film by 53%. Copyright © 2014 John Wiley & Sons, Ltd.     

Lake extent changes in Basotu,Tanzania: a mixed-methods approach to understanding the impacts of anthropogenic influence and climate variability

Incompatible land use is a major contributor to ecosystem degradation, and is often exacerbated by climate change impacts. We investigate Lake Basotu, Tanzania as a case study where natural lake variability has been affected by agricultural land use. Comparisons between a satellite-derived history of lake surface area, local precipitation records, and corresponding anthropogenic activity show the impacts of agricultural and historical practices. We argue that insufficient consideration to the wider ecological impacts of large agricultural projects has lasting implications. This is particularly true in semi-arid environments where food production demands need to be continuously met. In the future, major conservation strategies should be investigated to maintain the environmental integrity and sustainability of freshwater resources.     

Trees and wood: working with natural river processes

A history of land clearance and riparian tree and wood management has resulted in limited riparian woodland and wood along British rivers. However, river management approaches are now being promoted that ‘work with natural processes’ to reduce flood risk through measures intended to restore, protect and emulate the natural function of catchments, rivers, estuaries and coasts. Wood has started to be reintroduced into river channels during river restoration and natural flood management activities, but this needs to be undertaken using appropriate quantities, locations and designs that mimic natural tree‐wood features. This paper reviews the knowledge that is needed to support wood reintroduction activities including (i) the characteristics of the riparian tree species and wood that are present; (ii) the importance of river size relative to that of trees and wood pieces; and (iii) the way trees, wood and geomorphic processes interact across rivers and floodplains of different energy and style.     

Evaluation of the thermal performance of frame walls enhanced with paraffin and hydrated salt phase change materials using a dynamic wall simulator

The incorporation of phase change materials (PCMs) in building materials for use as latent heat storage and for potential reduction of energy requirements is an on-going field of study. In this paper, the development and testing of PCM-enhanced cellulose insulation for use in frame walls is presented. Two types of PCMs, paraffin-based and hydrated salt-based, were mixed into loose-fill cellulose insulation at concentrations of 10% and 20% (by the weight of the wallboard) in a 1.22 m × 1.22 m (48 in. × 48 in.) frame wall cavity. The thermally-enhanced frame walls were heated and allowed to cool down in a dynamic wall simulator that replicated the sun's exposure in a wall of a building on a typical summer day. Peak heat fluxes, total “daily” heat flows, and surface and air temperatures were measured and recorded. Results show that the paraffin-based PCM-enhanced insulation reduced the average peak heat flux by up to 9.2% and reduced the average total “daily” heat flow up to 1.2%. Because of the hydroscopic behavior of un-encapsulated hydrated salt, the hydrated salt-based PCM-enhanced insulation did not provide any thermal storage benefit.     

Peptide fingerprint of high quality Campania white wines by MALDI-TOF mass spectrometry

Food traceability is essential to preserve the identity of unique quality traits against frauds or commercial disputes. Therefore, there is a growing demand of new traceability systems for the collection of information related to units/batches of food ingredients and products.     

High Performance, Low-Dose Radiography Systems for Space and Remote Site Applications

Medical imaging applications using X- and gamma-rays have reached outstanding levels of complexity and performance, thanks to technology achievements in the fields of radiography, tomography and high resolution synchrotron devices. The operability of the related instrumentation resides in the availability of highly qualified specialists, as well as of medical doctors for diagnoses and treatment. This is a problem for personnel working in difficult ambient conditions as can be found in remote sites like Arctica, Antarctica and under-populated, desolated or mountainous regions on Earth. Astronauts, during long permanence at the Space Station or on future mission to Mars are potentially subject to risks such as traumas, fractures or diseases which would require semi-automated, easy-to-handle application of X-ray radiographic devices. For this purpose, the possible use of imaging instrumentation based on solid state detectors is discussed with special regard to CdZnTe pixel devices, now available with sub-mm resolution. The use of these semiconductor detectors will also allow to perform image diagnostics at much lower doses compared to the current plate-based radiographic techniques.