Detection and replacement of a failing node in the wireless sensors networks

The lifetime in a wireless network, in particular a wireless sensor network, depends strongly on the connectivity factor between nodes. Several factors can be at the origin of a connectivity rupture such as: lack of energy on a significant node level, infection of a vital node by a malevolent code and a logical or physical failure of a primary node. This rupture can lead in some cases to a reconfiguration of the network by generating a prejudicial overhead or in other cases to a failure of the mission assigned to the network. In this paper, we propose a DRFN approach (Detection and Replacement of a Failing Node) for the connectivity maintenance by carrying out a replacement chain according to a distributed algorithm. Through simulation, we have shown our approach efficiency. Compared with similar work, our proposed approach consumes less energy, and improves the percentage of reduction in field coverage.     

Handwriting synthesis: classifications and techniques

Handwriting synthesis is the automatic generation of data that resemble natural handwriting. Although handwriting synthesis has recently gained increasing interest, the area still lacks a stand-alone review. This paper provides classifications for the different aspects of handwriting synthesis. It presents the applications, techniques, and evaluation methods for handwriting synthesis based on the several aspects that we identify. Then, it discusses various synthesis techniques. To the best of our knowledge, this paper is the only stand-alone survey on this topic, and we believe it can serve as a useful reference for the researchers in the field of handwriting synthesis.     

Properties of Coated Controlled Release Diammonium Phosphate Fertilizers Prepared with the Use of Bio-based Amino Oil

In an effort to enhance the efficiency of fertilizer use and minimize their negative impact on the environment, a novel biomass-based, functional controlled-release fertilizer was used to improve nutrient use efficiency and increase crop production systems for more sustainable agriculture practices. Here, bio-based amino-oil (Priamine) mixtures were proposed as an outer coating with different layers for the control of phosphorus release from diammonium Phosphate (DAP). These hydrophobic coatings conferred excellent barrier properties and flexibility to coatings. The morphological characterization of the coated fertilizer was performed by scanning electronic microscopy (SEM), electronic diffraction X-ray (EDX) and mapping, and revealed the formation of a cohesive film and a good adhesion between DAP fertilizer and coating film. The release rate of nutrients (phosphate) in water was investigated by UV–Vis spectrophotometer. The effect of coating thickness was investigated on release time and diffusion coefficient of phosphor release in distilled water. Release time increased with the coating thickness. The diffusion coefficient of nutrient release decreased with the coating thickness. Compared with uncoated granule which is totally solubilized after less than 2 hours, the P release profiles of the coated granules reached the equilibrium stage approximately after 98 and 126 hours when the DAP is coated with only Priamine single-layer (1L) and double-layer (2L), respectively. Moreover, the strategy adopted has successfully provided a very slow release and long-term availability of nutrient sources with bio-based coating oil compared to uncoated fertilizer (DAP) and therefore exhibited promising application for sustainable development of modern agriculture and circular economic.     

Tissue metal concentrations and histopathology of rats gavaged with vitrified soil obtained from the former Charleston Naval Shipyard (SC,USA)

Male Sprague Dawley^® rats were administered a vitrified material obtained from the former Charleston Naval Shipyard (Charleston, SC, USA) by gavage once daily for 32 days. Group mean body weight of treated animals was within ±5.4% of controls. No gross or histopathological changes were observed when animals were treated with 67, 174, or 370 mg/kg per day. Analysis of heavy metals revealed a statistically significant increase only in the concentration of arsenic in the livers of animals treated with 174 or 370 mg/kg per day versus controls. Although there was a statistically significant increase in liver arsenic levels, the concentrations were far below mean soil concentrations for western and eastern United States. If the standard assumption of 100% absorption is used, the concentrations observed in the present study are about 20 times less than the average background soil levels in these regions. Based on this, it is concluded that the vitrified material would not pose a public health risk for its intended use as an additive for asphalt and glass beams.     

Gas Permeability of Partially Hydrated Geosynthetic Clay Liners

A series of gas permeability tests were performed on four partially hydrated geosynthetic clay liners (GCLs) (GCL1, GCL2, GCL3, and GCL4). All GCLs consisted of essentially dry bentonite (powder or granular) sandwiched between geotextile layers. The geotextiles were held together as a composite material by needle-punching, except GCL-4, which was stitch bonded. GCL-2 had a special characteristic, which consisted of a cover nonwoven geotextile layer impregnated with powdered bentonite. The gas permeability was found to be very sensitive to the change of moisture content and volumetric water content. The results also highlighted the effects of the GCL structures (bentonite impregnation, needle punching, and stitch bonding) and bentonite forms (granular and powdered) on the gas permeability. The needle punched GCLs tended to have lower gas permeability than the stitch bonded GCLs, and the GCLs containing granular bentonite tended to have higher gas permeability than the GCLs containing powdered bentonite. The bentonite impregnation of the nonwoven geotextile also contributed to lower gas permeability. For comparable conditions, these effects resulted in a reduction of up to three orders of magnitude of gas permittivity from one GCL to another. However, the effect of the differences between the GCLs on gas permeability, at high volumetric water content (>70%), was overridden by the presence of the overburden pressure during hydration. Furthermore, the overburden pressure also had an important role in the reduction of gas permeability, which implies that the GCL should be subjected to confinement at the time of installation or hydration in order to obtain a low gas permeability.     

Reactive congestion control algorithm in an ATM node

This paper discusses the congestion phenomenon on anAtm node and presents an analytical approach to follow the cumulated delays on the network. It proposes an adaptation algorithm of the sources rate with the evolving congestion state of a node by a reactive approach.     

Les alliages terre rare-magnesium riches en magnesium et leur application au stockage de l'hydrogene

The LnMg₁₂, Ln₂Mg₁₇ and Ln₅Mg₄₁ alloys (Ln = La, Ce or mischmetal) have been investigated. The composition range and the stability of the various phases have been determined. They decompose during hydriding with formation of magnesium hydride and the corresponding rare-earth hydride. The study of absorption-desorption hydriding cycles at different temperatures and various pressures shows that these alloys could be used as high performance hydrogen storage materials.     

On the solution of the linear least squares problems and pseudo-inverses

It is known that the computed least squares solutionx ofAx=b, in the presence of the round-off error, satisfies the perturbed equation(A+E)(x+h)=b+f. The practical considerations of computing the solution are discussed and it is found that rank(A+E)=rank (A). A general analysis of the condition of the linear least squares problems and pseudo-inverses is then presented using this assumption. Norms of relevant round-off error perturbations are estimated for two known methods of solution. Comparison between different algorithms is given by numerical examples.     

Micro X-ray visualisation of the interaction of geosynthetic clay liner components after partial hydration

High-resolution X-ray tomography was used to observe a partially hydrated geosynthetic clay liner (GCL) specimen to gain a better understanding of the interaction of its compnents (i.e., geotextiles, fibres and bentonite) on partial hydration when deployed as part of a composite liner system. Detailed in-situ studies of hydration processes in GCLs has proven difficult despite more than two decades of effort. X-ray tomographs were collected at spatial resolutions of 12 and 7?μm to identify the different components within a GCL, as well as to examine in finer detail their interaction within the GCL after initial partial hydration. Tomograph projections provided an excellent aspect of the interaction of these components and some concepts, such as the presence of shearing features within the bentonite component, may require re-consideration based on evidence from X-ray tomography.     

Effect of Wet–Dry Cycles and Cation Exchange on Gas Permeability of Geosynthetic Clay Liners

A series of gas permeability tests were performed on a partially hydrated needle punched geosynthetic clay liner (GCL) after exposure to wet–dry cycles and ion exchange. To be able to evaluate the effect of wetting and drying cycles combined with the effect of cation exchange, three sets of GCL samples were prepared with different types of hydrating liquid. The first set of GCL samples was hydrated with de-ionized water, which formed a baseline test series. The second and third sets were hydrated with 0.0125 and 0.125?M calcium chloride (CaCl2) solutions, respectively. All three sets of GCL samples were subjected to multiple wetting and drying cycles before undergoing gas permeability tests. Gas permeability of the GCL, hydrated with 0.0125?M calcium chloride solution, was found to be approximately one order of magnitude higher than that of the GCL hydrated with de-ionized water, whereas gas breakthrough flow was observed for all but the first wetting cycle on GCLs hydrated with the stronger 0.125?M calcium chloride solution.