Artificial compliance inherent to the intrinsic cohesive zone models: criteria and application to planar meshes

In this study, criteria on the artificial compliance due to intrinsic cohesive zone models are presented. The approach is based on a micromechanical model for a collection of cohesive zone models embedded between each mesh of a finite element-type discretization. The overall elastic behaviour of this cohesive volumetric medium is obtained using homogenization techniques and is given in a closed-form as function of bulk properties of the relevant material and mesh parameters (the mesh type and size). Practical criteria are obtained for the calibration of the cohesive stiffnesses bounding the additional compliance inherent to intrinsic cohesive zone models by lower value. For isotropic planar discretizations (e.g. Delaunay mesh), a rigorous bound is derived whereas convenient estimates are given for non-isotropic discretizations (e.g. regular mesh).     

Mycotic aneurysms of the carotid artery: ligation vs. reconstruction--case report and review of the literature

Mycotic aneurysms of the extracranial carotid artery are very uncommon, with only twenty-nine cases reported in the medical literature. This is a report of a mycotic aneurysm of the common carotid artery caused by septic cervical lymphadenopathy. A review of the literature is presented in an attempt to elucidate which surgical approach is superior, ligation or repair of the carotid artery.     

New Cloud Consolidation Architecture for Electrical Energy Consumption Management

Cloud computing is taking more extensive space in the research field. Cloud architectures will need to worry about energy in its various forms, to be profitable, on the one hand, and comply with environmental constraints （energy consumption and CO2 emission） on the other hand. VM （virtual machines） consolidation （VMs in this document）, among other techniques, must take into account the consumption of electrical energy, for example, while providing a level of performance that meets the requirements of SLAs （service level agreements）. In our work, we focus on an architecture configuration to manage virtual machines in a data center, in order to optimize the consumption of energy, and meet SLAs＇s constraints at the same time, by grafting a tracing component of the multiple consolidation plans that leads to an optimal configuration to finally give the order of the migration machinery to a minimum number of servers switched on, knowing that VMs （virtual machines） that coexist in the same server, are at risk of congestion and interference.     

Selective Cocatalyst Decoration of Narrow-Bandgap Broken-Gap Heterojunction for Directional Charge Transfer and High Photocatalytic Properties

Narrow-bandgap semiconductors are promising photocatalysts facing the challenges of low photoredox potentials and high carrier recombination. Here, a broken-gap heterojunction Bi/Bi₂S₃/Bi/MnO₂/MnO_x, composed of narrow-bandgap semiconductors, is selectively decorated by Bi, MnO_x nanodots (NDs) to achieve robust photoredox ability. The Bi NDs insertion at the Bi₂S₃/MnO₂ interface induces a vertical carrier migration to realize sufficient photoredox potentials to produce O₂^•− and ^•OH active species. The surface decoration of Bi₂S₃/Bi/MnO₂ by Bi and MnO_x cocatalysts drives electrons and holes in opposite directions for optimal photogenerated charge separation. The selective cocatalysts decoration realizes synergistic surface and bulk phase carrier separation. Density functional theory (DFT) calculation suggests that Bi and MnOx NDs act as active sites enhancing the absorption and reactants activation. The decorated broken-gap heterojunction demonstrates excellent performance for full-light driving organic pollution degradation with great commercial application potential.     

A fast calibration-independent method for complex permittivity determination at microwave frequencies

A transmission/reflection microwave method based on uncalibrated S-parameter measurements for complex permittivity determination of dielectric materials is presented. There are three main advantages of the proposed method. First, the measurements are performed without the need of any calibration standards. Second, it does not require any additional dielectric sample with different thickness; two uncalibrated measurements are required: (i) with a sample filled waveguide and (ii) with an empty waveguide. Third, it does not need a precise location or precise shifting distance of the sample inside the waveguide. The method is iterative needing an initial guess to start the mathematical calculations, and high measurement accuracy can be expected. The method is validated by complex uncalibrated S-parameter measurements at X-band frequencies of low-loss samples (Teflon, Celotex and Duroplex) fitted into a waveguide section.     

Interfacial charge transfer and photocatalytic activity in a reverse designed Bi2O3/TiO2 core-shell

In this study, the electronic and photocatalytic properties of core-shell heterojunctions photocatalysts with reversible configuration of TiO₂ and Bi₂O₃ layers were studied. The core-shell nanostructure, obtained by efficient control of the sol-gel polymerization and impregnation method of variable precursors of semiconductors, makes it possible to study selectively the role of the interfacial charge transfer in each configuration. The morphological, optical, and chemical composition of the core-shell nanostructures were characterized by high-resolution transmission electron microscopy, UV-visible spectroscopy and X-ray photoelectron spectroscopy. The results show the formation of homogenous TiO₂ anatase and Bi₂O₃ layers with a thickness of around 10 and 8 nm, respectively. The interfacial charge carrier dynamic was tracked using time resolved microwave conductivity and transition photocurrent density. The charge transfer, their density, and lifetime were found to rely on the layout layers in the core-shell nanostructure. In optimal core-shell design, Bi₂O₃ collects holes from TiO₂, leaving electrons free to react and increase by 5 times the photocatalytic efficiency toward H₂ generation. This study provides new insight into the importance of the design and elaboration of optimal heterojunction based on the photocatalyst system to improve the photocatalytic activity.     

Survival and metabolic activity of lux-marked Escherichia coli O157:H7 in different types of milk

Escherichia coli O157:H7 is a potentially lethal pathogen which has been responsible for several outbreaks of milk-borne illness in recent years. The objective of this study was to evaluate the survival and metabolic activity (indexed by bioluminescence) of a chromosomally lux-marked strain of Esch. coli O157:H7 in raw, pasteurized and microfiltered pasteurized milk at 4 and 20°C for up to 14 d. Results showed that the population of Esch. coli O157:H7 and its metabolic activity decreased in all samples during storage at 4°C, with no significant differences in numbers observed between the different milk types; but metabolic activity was significantly higher (P<0·05) in the microfiltered pasteurized milk than that in raw milk. At 20°C, Esch. coli O157:H7 counts and cell activity peaked at day 2, and then declined progressively. At 20°C, survival and metabolic activity were significantly lower in raw milk compared with pasteurized milk. We conclude that storage temperature is more important in regulating the survival of Esch. coli O157 in contaminated milk than its origin/pre-treatment conditions.     

Tuning the Electronic Bandgap of Graphdiyne by H-Substitution to Promote Interfacial Charge Carrier Separation for Enhanced Photocatalytic Hydrogen Production

Graphdiyne (GDY), which features a highly π-conjugated structure, direct bandgap, and high charge carrier mobility, presents the major requirements for photocatalysis. Up to now, all photocatalytic studies are performed without paying too much attention on the GDY bandgap (1.1 eV at the G₀W₀ many-body theory level). Such a narrow bandgap is not suitable for the band alignment between GDY and other semiconductors, making it difficult to achieve efficient photogenerated charge carrier separation. Herein, for the first time, it is demonstrated that tuning the electronic bandgap of GDY via H-substitution (H-GDY) promotes interfacial charge separation and improves photocatalytic H₂ evolution. The H-GDY exhibits an increased bandgap energy ( ≈ 2.5 eV) and exploitable conduction band minimum and valence band maximum edges. As a representative semiconductor, TiO₂ is hybridized with both H-GDY and GDY to fabricate a heterojunction. Compared to the GDY/TiO₂, the H-GDY/TiO₂ heterojunction leads to a remarkable enhancement of the photocatalytic H₂ generation by 1.35 times under UV–visible illumination (6200 µ mol h⁻¹ g⁻¹) and four times under visible light (670 µ mol h⁻¹ g⁻¹). Such enhancement is attributed to the suitable band alignment between H-GDY and TiO₂, which efficiently promotes the photogenerated electron and hole separation, as supported by density functional theory calculations.     

Assessment of solar and wind energy as motive for potential hydrogen production of Algeria country; development a methodology for uses hydrogen-based fuel cells

This study is based on method of storing the part of renewable energy in the hydrogen form for using in a fuel cell at the absence of solar radiation due to overcast day or in the night. In addition, the system advantage don't need a batteries compared with other systems. The present work is compared energy potential of the wind and solar with the results of hydrogen production and to address the various obstacles to study and evaluation. This work is assessment the renewable resources in various sites of Algeria, especially in Adrar area which is one regions of the high solar energy in the world, where the radiation rates exceed more than $2300kWh/m^2$ per year, the area is also characterized by high wind power. In fact, by these two energy sources (solar and wind) that it characterized by Adrar, it's interesting to combine electrical producing energy and hydrogen production. The studies indicate that there are the meteorological factors related to the nature of site (irradiation, temperature and wind speed) are linked to the generation of electricity by renewable energy. The results obtained showing that the hydrogen production related to the solar radiation values, where southern of Algeria has more hydrogen potential compared with the northern. The simulation results show that the energy supplied by a photovoltaic module type UDTS 50 can supply energy for ten electrolyzer cells which are connected in series with this module.     

From inter-organizational business process models to service-oriented architecture models

Today’s business processes become increasingly complex and often cross the boundaries of the organizations. On the one hand, to support their business processes, modern organizations use enterprise information systems that need to be aware of the organizations’ processes and contexts. Such systems are called Process-Aware Information System (PAIS). On the other hand, the service-oriented architecture (SOA) is a fast emerging architectural style that has been widely adopted by modern organizations to design and implement PAIS that support their business processes. This paper aims to bridge the gap between inter-organizational business processes and SOA-based PAISs that support them. It proposes a novel model-driven design method that generates SOA models expressed in SoaML taking the specification of collaborative business processes expressed in BPMN as input. We present the principles underlying the approach, the state of an ongoing implementation, and the results of two studies conducted to empirically validate the method in the context of ERP key processes.