Computational study of three dimensional viscous flow through a turbine cascade using a multi-domain spectral technique

The three dimensional viscous flow through a planar turbine cascade is numerically simulated by direct solution of the incompressible Navier-Stokes equations. Flow dependence in the spanwise direction is represented by direct expansion in Chebyshev polynomials, while the discretization on planes parallel to the endwalls is accomplished using the spectral element method. Elemental mapping from the physical to the computational space uses an algebraic mapping technique. A fractional time stepping method that consists of an explicit nonlinear convective step, an implicit pressure correction step, and an implicit viscous step is used to advance the Navier-Stokes equations forward in time. Results computed at moderate Reynolds numbers show a three dimensional endwall flow separation, a midspan separation of the blade suction surface boundary layer, and other three-dimensional features such as the presence of a saddle point flow in the endwall region. In addition, the computed skin friction lines are shown to be orthogonal to the surface vorticity lines, demonstrating the accuracy achievable in the present method

PRECEPT: A Framework for Ethical Digital Forensics Investigations.

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Cyber-enabled crimes are on the increase, and law enforcement has had to expand many of their detecting activities into the digital domain. As such, the field of digital forensics has become far more sophisticated over the years and is now able to uncover even more evidence that can be used to support prosecution of cyber criminals in a court of law. Governments, too, have embraced the ability to track suspicious individuals in the online world. Forensics investigators are driven to gather data exhaustively, being under pressure to provide law enforcement with sufficient evidence to secure a conviction. Yet, there are concerns about the ethics and justice of untrammeled investigations on a number of levels. On an organizational level, unconstrained investigations could interfere with, and damage, the organization’s right to control the disclosure of their intellectual capital. On an individual level, those being investigated could easily have their legal privacy rights violated by forensics investigations. On a societal level, there might be a sense of injustice at the perceived inequality of current practice in this domain. This paper argues the need for a practical, ethically-grounded approach to digital forensic investigations, one that acknowledges and respects the privacy rights of individuals and the intellectual capital disclosure rights of organisations, as well as acknowledging the needs of law enforcement. We derive a set of ethical guidelines, then map these onto a forensics investigation framework. We subjected the framework to expert review in two stages, refining the framework after each stage. We conclude by proposing the refined ethically-grounded digital forensics investigation framework. Our treatise is primarily UK based, but the concepts presented here have international relevance and applicability. In this paper, the lens of justice theory is used to explore the tension that exists between the needs of digital forensic investigations into cybercrimes on the one hand, and, on the other, individuals’ rights to privacy and organizations’ rights to control intellectual capital disclosure. The investigation revealed a potential inequality between the practices of digital forensics investigators and the rights of other stakeholders. That being so, the need for a more ethically-informed approach to digital forensics investigations, as a remedy, is highlighted, and a framework proposed to provide this. Our proposed ethically-informed framework for guiding digital forensics investigations suggest a way of re-establishing the equality of the stakeholders in this arena, and ensuring that the potential for a sense of injustice is reduced. Justice theory is used to highlight the difficulties in squaring the circle between the rights and expectations of all stakeholders in the digital forensics arena. The outcome is the forensics investigation guideline, PRECEpt: Privacy-Respecting EthiCal framEwork, which provides the basis for a re-aligning of the balance between the requirements and expectations of digital forensic investigators on the one hand, and individual and organizational expectations and rights, on the other

Conformally covariant quantization of Maxwell field in de Sitter space

In this article, we quantize the Maxwell ("massless spin one") de Sitter field in a conformally invariant gauge. This quantization is invariant under the SO$_0(2,4)$ group and consequently under the de Sitter group. We obtain a new de Sitter invariant two-points function which is very simple. Our method relies on the one hand on a geometrical point of view which uses the realization of Minkowski, de Sitter and anti-de Sitter spaces as intersections of the null cone in \setR^6 and a moving plane, and on the other hand on a canonical quantization scheme of the Gupta-Bleuler type.Comment: v2 is is the definitive (improved compare to v1) versio

Adaptive plasticity in the mouse mandible

BACKGROUND: Plasticity, i.e. non-heritable morphological variation, enables organisms to modify the shape of their skeletal tissues in response to varying environmental stimuli. Plastic variation may also allow individuals to survive in the face of new environmental conditions, enabling the evolution of heritable adaptive traits. However, it is uncertain whether such a plastic response of morphology constitutes an evolutionary adaption itself. Here we investigate whether shape differences due to plastic bone remodelling have functionally advantageous biomechanical consequences in mouse mandibles. Shape characteristics of mandibles from two groups of inbred laboratory mice fed either rodent pellets or ground pellets mixed with jelly were assessed using geometric morphometrics and mechanical advantage measurements of jaw adductor musculature. RESULTS: Mandibles raised on diets with differing food consistency showed significant differences in shape, which in turn altered their biomechanical profile. Mice raised on a soft food diet show a reduction in mechanical advantage relative to mice of the same inbred strain raised on a typical hard food diet. Further, the soft food eaters showed lower levels of integration between jaw regions, particularly between the molar and angular region relative to hard food eaters. CONCLUSIONS: Bone remodelling in mouse mandibles allows for significant shifts in biomechanical ability. Food consistency significantly influences this process in an adaptive direction, as mice raised on hard food develop jaws better suited to handle hard foods. This remodelling also affects the organisation of the mandible, as mice raised on soft food appear to be released from developmental constraints showing less overall integration than those raised on hard foods, but with a shift of integration towards the most solicited regions of the mandible facing such a food, namely the incisors. Our results illustrate how environmentally driven plasticity can lead to adaptive functional changes that increase biomechanical efficiency of food processing in the face of an increased solicitation. In contrast, decreased demand in terms of food processing seems to release developmental interactions between jaw parts involved in mastication, and may generate new patterns of co-variation, possibly opening new directions to subsequent selection. Overall, our results emphasize that mandible shape and integration evolved as parts of a complex system including mechanical loading food resource utilization and possibly foraging behaviour

Low Voltage Totally Free Flexible RF MEMS Switch With Anti-Stiction System

This paper concerns a new design of RF MEMS switch combined with an innovative process which enable low actuation voltage (<5V) and avoid stiction. First, the structure described with principal design issues, the corresponding anti-stiction system is presented and FEM simulations are done. Then, a short description of the process flow based on two non polymer sacrificial layers. Finally, RF measurements are presented and preliminary experimental protocol and results of anti-stiction validation is detailed. Resulting RF performances are -30dB of isolation and -0.45dB of insertion loss at 10 GHz.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/16838

Ethological risk factors of West nile infection of wild birds in Senegal

Serological studies performed in 2003, as well as viral isolations demonstrated that West Nile fever (WNF) was endemic in Senegal (West Africa). Large populations of potentially infected birds fly each year from West Africa to Europe. The goal of this study was to identify potential reservoirs of West Nile virus among Senegalese birds and ethological features related to WN infection. In October 2003, wild birds were trapped and sampled in two different locations: the Ornithological Djoud¿j National Park, located in the Senegal River Basin and in a village located in the Ferlo area (northern Senegal). Sera were analysed using an inhibition immunocapture enzyme-linked immunosorbent assay. Serological data were analysed using a generalized linear Poisson model. Seven ecological features that may influence the exposure of birds to mosquito bites were included as explanatory variables: the trapping location, the migrating status, the feeding site, the resting site, the nesting type, the herd instinct level, and affinity with urban areas. A total of 422 birds representing 49 species were trapped and sampled. The overall prevalence rate was 5.5%. Resident birds building platform or cup nests, as well as birds feeding on soil or having low urban areas affinity were more at risk than others (p=0.01, p=0.02 and p=0.02 respectively). Potential consequences of these results on virus dissemination and WN reservoir birds are discussed. (Résumé d'auteur

EMBRACE@Nancay: An Ultra Wide Field of View Prototype for the SKA

A revolution in radio receiving technology is underway with the development of densely packed phased arrays for radio astronomy. This technology can provide an exceptionally large field of view, while at the same time sampling the sky with high angular resolution. Such an instrument, with a field of view of over 100 square degrees, is ideal for performing fast, all-sky, surveys, such as the "intensity mapping" experiment to measure the signature of Baryonic Acoustic Oscillations in the HI mass distribution at cosmological redshifts. The SKA, built with this technology, will be able to do a billion galaxy survey. I will present a very brief introduction to radio interferometry, as well as an overview of the Square Kilometre Array project. This will be followed by a description of the EMBRACE prototype and a discussion of results and future plans.Comment: to appear in proceedings of the INFIERI Summer School INtelligent Signal Processing for FrontIEr Research and Industry, Paris 201

Etude de la production d'hydrogène en bioréacteur par la bactérie photosynthétique Rhodobacter capsulatus 2. Transformation du lactate et bilans carbonés

La dégradation du lactate par la bactérie photosynthétique Rhodobacter capsulatus cultivée dans un photobioréacteur en anaérobiose, à la lumière, en limitation d'azote, a été mesurée ainsi que la production d'hydrogène par la nitrogénase. En réacteur ouvert à faible taux de dilution (D = 0,04 h-1), le lactate initialement à 30 mM est dégradé à près de 90 % avec une faible accumulation (< 1-2 mM) des produits de dégradation (formiate et acétate). C'est dans ces conditions qu'on observe la meilleure production d'hydrogène (44 ml • h-1 • h-1). Lorsque la culture bactérienne devient trop dense en réacteur fermé ou an recyclage des bactéries, Il y a apparemment passage à un métabolisme de type fermentatif, chute de la production d'hydrogène et accumulation d'acides organiques (formique, acétique, propionique) provenant du lactate. Dans ces conditions, il n'y a pas diminution de la charge de carbone organique. Outre la présence de ces acides à courtes chaînes, les bilans carbonés; font apparaître la présence, dans le surnageant de la culture, de substances carbonées exocellulaires non identifiées pouvant représenter jusqu'à 50 % du flux carboné sortant.A 10 l photobioreactor, consisting of a PVC tubing, spiral-coiled so as to form a plane light captor (DELACHAPELLE et al., 1990), was used to study the degradation of lactate by the photosynthetic bacterium Rhodobacter capsulatus strain B10. The bacterial culture was continuously circulated in the reactor so as to maintain a homogeneous suspension, to optimize illumination of the cells, and make a well-mixed reactor for optimal nutrient transfers and degas ing of the medium. The bacterium was cultivated anaerobically under photoheterotrophic and N-limited conditions. The bioreactor was operated in three modes : as an open system (chemostat), as a closed system (batch), and as an open system with phases of bacteria recycling through the use of an ultrafiltration cell.When the bioreactor functioned as a chemostat, at low dilution rate (D < 0.04 h-1) and at relatively low bacterial density (A660 nm < 2.5), up to 90 % of the added lactate (initial concentration 30 mM) was degraded; the concentration of degradation products (formate, acetate) remained low (<2 mM). Under these conditions nitrogenase-mediated H2 production was maximal (44 ml • h-1 • l-1). In batch cultures or when the cells were « recycled » in the chemostat by ultrafiltration, the increase in absorbancy led to a decrease in cell illumination and the bacteria apparently switched from a photosynthetic of a fermentative type of metabolism; lactate was converted into formate + acetate + propionate, no H2 was produced. From the determination of the carbon balance between the influent and the effluent medium, the presence of non identified extracellular carbon compounds (up to 50 % of the C content of the effluent) was proved

Electrodialytic processes in solid matrices. New insights into batteries recycling. A review.

Electrodialytic Remediation has been widely applied to the recovery of different contaminants from numerous solid matrices solving emerging issues of environmental concern. Results and conclusions reported in studies about real contaminated matrices are summarizes in this work. The influence of the pH value on the treatment effectiveness has been widely proved highlighting the phenomenon “water splitting” in the membrane surface. This dissociation of water molecules is related to the “limiting current” which is desirable to be exceed at the Anion Exchange Membrane in order to produce the entering of protons toward solid matrix. Other important parameters for the optimization of the technique, such as the current density and the liquid to solid ratio, are also discussed through the revision of studies using real solid matrices. This work also focusses on the pioneer proposal of electrokinetic technologies for the recycling of lithium ion batteries considering the relevance of waste properties in the design and optimization of the technique. From a thorough literature revision, it could be concluded that further experimental results are needed to allow an optimal application of the technique to the rising problem of residues from batteries. The main aim of this work is to take the first steps in the recovery of valuable metals from spent batteries, such as Li and Co, incorporating principles of green chemistry.The authors acknowledge the financial support from the “Plan Propio de Investigación de la Universidad de Málaga with Project numbers: PPIT.UMA.B1.2017/20 and PPIT.UMA.B5.2018/17 and the European project THROUGH H2020-MSCA-RISE- 2017-778045. The first author also acknowledge the postdoctoral contract obtained from University of Malaga