Algorithms and Proofs Inheritance in the FOC Language

In this paper, we present the FOC langugage, dedicated to the development of certified computer algebra libraries (that is sets of programs). These libraries are based on a hierarchy of implementations of mathematical structures. After presenting the core set of features of our language, we describe the static analyses, which reject inconsistent programs. We then show how we translate FOC definitions into OCAML and COQ, our target languages for the computational part and the proof checking, respectively.     

Estimation of rotor angles of synchronous machines using artificial neural networks and local PMU-based quantities

This paper investigates a possibility for estimating rotor angles in the time frame of transient (angle) stability of electric power systems, for use in real-time. The proposed dynamic state estimation technique is based on the use of voltage and current phasors obtained from a phasor measurement unit supposed to be installed on the extra-high voltage side of the substation of a power plant, together with a multilayer perceptron trained off-line from simulations. We demonstrate that an intuitive approach to directly map phasor measurement inputs to the neural network to generator rotor angle does not offer satisfactory results. We found out that a good way to approach the angle estimation problem is to use two neural networks in order to estimate the sin(δ) and cos(δ) of the angle and recover the latter from these values by simple post-processing.Simulation results on a part of the Mexican interconnected system show that the approach could yield satisfactory accuracy for real-time monitoring and control of transient instability.     

Triazolophthalazines: Easily Accessible Compounds with Potent Antitubercular Activity

Tuberculosis (TB) remains one of the major causes of death worldwide, in particular because of the emergence of multidrug‐resistant TB. Herein we explored the potential of an alternative class of molecules as anti‐TB agents. Thus, a series of novel 3‐substituted triazolophthalazines was quickly and easily prepared from commercial hydralazine hydrochloride as starting material and were further evaluated for their antimycobacterial activities and cytotoxicities. Four of the synthesized compounds were found to effectively inhibit the Mycobacterium tuberculosis (M.tb) H₃₇Rv strain with minimum inhibitory concentration (MIC) values <10 μg mL^?1, whereas no compounds displayed cytotoxicity against HCT116 human cell lines (IC₅₀>100 μm ). More remarkably, the most potent compounds proved to be active to a similar extent against various multidrug‐resistant M.tb strains, thus uncovering a mode of action distinct from that of standard antitubercular agents. Overall, their ease of preparation, combined with their attractive antimycobacterial activities, make such triazolophthalazine‐based derivatives promising leads for further development.     

Miscible raw lignin/nylon 6 blends: Thermal and mechanical performances

Environmentally friendly bio‐filled composites of various proportions of polyamide 6 (PA6) and technical lignin have been prepared using a twin‐screw extruder. Transmission electron microscopy has been used to investigate the morphology of the composites. It reveals homogeneous single phase system, indicating the miscibility of PA6 and lignin. The glass transition temperature of the blends, determined by DMA, was shifted systematically to higher temperature with increasing concentration of lignin which highlights the miscibility of both components. In addition, Fourier Transform Infrared analyses have shown that new specific hydrogen‐bonding interactions are formed between hydroxyl groups of lignin and amine groups of the PA6. The presence of these intermolecular interactions between PA6 and lignin strongly influenced the thermal stability of the blends by lowering the onset of the blend's degradation process. However, the blends exhibit good mechanical properties whatever the lignin content. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42963.     

Photoluminescence from Liquid‐Exfoliated WS2 Monomers in Poly(Vinyl Alcohol) Polymer Composites

While liquid phase exfoliation can be used to produce nanosheets stabilized in polymer solutions, very little is known about the resultant nanosheet size, thickness, or monolayer content. The present study uses semiquantitative spectroscopic metrics based on extinction, Raman, and photoluminescence (PL) spectroscopy to investigate these parameters for WS₂ nanosheets exfoliated in aqueous poly(vinyl alcohol) (PVA) solutions. By measuring Raman and PL simultaneously, the monolayer content can be tracked via the PL/Raman intensity ratio while varying processing conditions. The PL is found to be maximized for a stabilizing polymer concentration of 2 g L^?1. In addition, the monolayer content can be controlled via the centrifugation conditions, exceeding 5% by mass in some cases. These techniques have allowed tracking the ratio of PL/Raman in a droplet of polymer‐stabilized WS₂ nanosheets as the water evaporates during composite formation. No evidence of nanosheet aggregation is found under these conditions although the PL becomes dominated by trion emission as drying proceeds and the balance of doping from PVA/water changes. Finally, bulk PVA/WS₂ composites are produced by freeze drying where >50% of the monolayers remain unaggregated, even at WS₂ volume fractions as high as 10%.     

Physiological and cognitive discontinuities: From mythical mediation to implicit discretization of architectural design tools

In architectural design, representation tools are often compared according to their alleged effects on the creativity of designers. Moreover, their mediating capacities are often mythicized, to such an extent that one might surmise the direct transmission of the mental images from the designer's consciousness to an external representation. In this speculative essay, we demonstrate that the process of representation at work in architectural design originates from the designer's consciousness natural cognitive ability, rather than from the use of a specific mediation tool between the designer and his environment, between the mentally constructed architectural project and its representation. The effects of any tool of representation—analog or digital—on our perceptual apparatus depend primarily on the cognitive mechanisms affecting the discontinuous flow of internal representations formed by our consciousness. In other words, we propose to shed a new light on these limitations through the heuristic modeling of an architectural project designer confronted with his own cognitive biases, and the limits of the representation processes. In the present essay, the discontinuities and uncertainties inherent to the processes of representation are reintegrate in the models.     

Transitioning to sustainable urban water management systems: how to define expected service functions?

Sustainable water management is a worldwide challenge for the twenty-first century. It involves replacing traditional management approaches with a new concept, often referred to as sustainable urban water management (SUWM). This paradigm shift means that SUWM systems must include new services, some of which have already emerged. However, no publications have presented the expected SUWM system in terms of the full range of services it would need to include, and no publications have proposed a method for identifying the services the system must provide. This paper proposes a method for identifying these services and presents a generic petal diagram to represent the service functions of the SUWM system. Moreover, this paper presents a new method for defining these services in a specific territory. This method is based on the confrontation between a general representation and the objectives of the stakeholders in a given system in a given territory. The method is illustrated with a full-scale case study on the Doua eco-campus (Lyon University). This method is intended to aid practitioners to manage its system and to transition to SUWM. It is designed to improve the transparency of decision formulation and to involve stakeholders in the process.     

Imaging of membrane electrode assemblies of proton exchange membrane fuel cells by X-ray computed tomography

X-ray computed tomography was applied for the 3D imaging of membrane electrode assemblies (MEAs) together with two attached gas diffusion layers. These samples were investigated as prepared and after voltage cycling. It was possible to achieve sub-μm resolution using a lab-based stand-alone tomography system as well as a tomography add-on for a scanning electron microscope. The carbon fibres of the gas diffusion layers could be clearly resolved and the catalyst layers could be visualized.X-ray computed tomography data were also used for the validation of results from scanning electron microscopy of cross-sections of membrane electrode assemblies where the sample is exposed to significant mechanical loads during sample preparation. More specifically, it was shown that the cracks observed in catalyst layers by scanning electron microscopy already exist in the membrane electrode assembly as prepared and are not a result of sample preparation. Finally it was shown that the crack density in the catalyst layers does not significantly change during voltage cycling which suggests that crack formation is not a principal cause of the observed performance decay of the MEA.     

Metal organic vapour-phase epitaxy growth of GaN wires on Si (111) for light-emitting diode applications

GaN wires are grown on a Si (111) substrate by metal organic vapour-phase epitaxy on a thin deposited AlN blanket and through a thin SiN_x layer formed spontaneously at the AlN/Si interface. N-doped wires are used as templates for the growth of core-shell InGaN/GaN multiple quantum wells coated by a p-doped shell. Standing single-wire heterostructures are connected using a metallic tip and a Si substrate backside contact, and the electroluminescence at room temperature and forward bias is demonstrated at 420 nm. This result points out the feasibility of lower cost nitride-based wires for light-emitting diode applications.