A Remark on the Characterization of Triangulated Graphs

In this study, we consider the problem of triangulated graphs. Precisely we give a necessary and sufficient condition for a graph to be triangulated. This gives an alternative characterization of triangulated graphs. Our method is based on the so-called perfectly nested sequences.

A Challenging Approach to Improve the Low Affinity of Acrylic Fibres to Be Successfully Dyed with a Bio-Colorant Extracted from Grape Marc

Acrylic fibres are highly crystalline and non-polar polymers,which makes their dyeing a very difficult step that poses real technical challenges.In order to overcome this concern,it is intended in this paper to modify acrylic fibers by different methods namely cationisation using the Crosscolor DRT then amidoximation using hydroxylamine hydrochloride and ammonium acetate.The resulted samples were dyed then with the bio-colorant extracted from grape marc.The effect of the pretreatment on fibers fine structure using X-ray diffraction and the scanning electron microscope(SEM)images and its correlation with the colour strength of the dyed fabrics was investigated.The dyeing parameters,such as dye bath pH and temperature on the performances of this dyeing process were studied.Good dyeing qualities and new shades varying from brown to grey and dark green have been obtained following process optimization,mordanting and modification of acrylic fibers by the technique of cationisation.

Effects of Carpobrotus edulis Extract on Oxidative Stress and 158N Oligodendrocyte Death

Objective Age-related diseases, including neurodegenerative diseases, are associated with oxidative stress and lipid peroxidation, and increase the levels of cholesterol auto-oxidation products such as 7β-hydroxycholesterol(7β-OHC). Thus, it is imperative to identify agents that can prevent 7β-OHC-induced side-effects. Methods We evaluated the potential protective effects of Carpobrotus edulis ethanol-water extract(EWe) on murine oligodendrocytes(158 N) cultured in the absence or presence of 7β-OHC(20 μg/mL, 24 h). The cells were incubated with EWe(20-200 μg/mL) 2 h before 7β-OHC treatment. Mitochondrial activity and cell growth were evaluated with the MTT assay. Photometric methods were used to analyze antioxidant enzyme [catalase(CAT) and glutathione peroxidase(GPx)] activities and the generation of lipid and protein oxidation products [malondialdehyde(MDA), conjugated diene(CD), and carbonylated proteins(CPs)]. Results Treatment with 7β-OHC induced cell death and oxidative stress(reflected by alteration in CAT and SOD activities). Overproduction of lipid peroxidation products(MDA and CDs) and CPs was also reported. The cytotoxic effects associated with 7β-OHC were attenuated by 160 μg/mL of EWe of C. edulis. Cell death induced by 7β-OHC treatment was ameliorated, GPx and CAT activities were restored to normal, and MDA, CD, and CP levels were reduced following C. edulis extract treatment. Conclusion These data demonstrate the protective activities of C. edulis EWe against 7β-OHC-induced disequilibrium in the redox status of 158 N cells, indicative of the potential role of this plant extract in the prevention of neurodegenerative diseases.

Removal of Cu(II),Pb(II),Mg(II),and Fe(II) by Adsorption onto Alginate/Nanocellulose Beads as Bio-Sorbent

Alginate blended with cellulose nanocrystals(CNC),cellulose nanofibers(CNF),and tri-carboxylate cellulose nanofibers(TPC-CNF)prepared and encapsulated in the form of microcapsules(bio-polymeric beads).The cellulosic nanomaterials that used in this study were investigated as nanomaterials for wastewater treatment applications.Batch experiments were performed to study the removal of copper,lead,magnesium,and iron from aqueous solutions by the prepared beads.The effects of the sorbent dosage and the modified polymers on the removing efficiency of the metal cations were examined.Atomic absorption was used to measure the metal ions concentrations.The modified bio-polymeric beads(Alg-CNF,Alg-CNC,and Alg-TPC-CNF)exhibited high-efficiency towards removing of the metal cations;Cu^(2+),Pb^(2+),Mg^(2+),and Fe^(2+).The Alg-TPC-CNF composite was exhibited excellent removing efficiency which around 95%for Pb,92%for Cu,43%for Fe and 54%for Mg.These outcomes affirm that the utilization of nanomaterials giving higher adsorption capacities contrasted with similar material in its micro or macrostructure form.

Antimicrobial activity of Tunisian Euphorbia paralias L.

Objective: To examine the potential antimicrobial activity of Euphorbia paralias L.(Euphorbiaeae) leaves and stems extracts.Methods: The antimicrobial activity was tested against six microbial strains: Escherichia coli ATCC 8739, Bacillus subtilis ATCC 6633, Salmonella enterica CIP 8039, Staphylococcus aureus ATCC 6538, Pseudomonas aeruginosa ATCC 9027 and Candida albicans ATCC 90028 by two different methods, the disk method and the dilution method.Results: Our results showed the important antimicrobial activity of the chloroform extract of the stems towards the majority of the strains by using both methods. Bacillus subtilis was the most sensitive strain(MIC = MBC = 15 mg/mL).Conclusion: Thus, some extracts of Euphorbia paralias can be used in the treatment of infectious diseases caused by microbes.

Equivalence of <i>K</i>-Functionals and Modulus of Smoothness Generated by a Generalized Dunkl Operator on the Real Line

This paper is intended to establish the equivalence between K-functionals and modulus of smoothness tied to a Dunkl type operator on the real line.

Modelling of the Quantum Transport in Strained Si/SiGe/Si Superlattices Based P-i-n Infrared Photodetectors for 1.3 - 1.55 μm Optical Communication

In this paper, a p-i-n heterojunction based on strain-compensated Si/Si1-xGex/Si multiple quantum wells on relaxed Si1-yGey is proposed for photodetection applications. The Si1-yGey/Si/Si1-xGex/Si/Si1-yGey stack consists in a W-like potential profile strain-compensated in the two low absorption windows of silica fibers infrared (IR) photodetectors. These computations have been used for the study of p-i-n infrared photodetectors operating at room temperature (RT) in the range 1.3 - 1.55 μm. The electron transport in the Si/Si1-xGex/Si multi-quantum wells-based p-i-n structure was analyzed and numerically simulated taking into account tunneling process and thermally activated transfer through the barriers mainly. These processes were modeled with a system of Schrodinger and kinetic equations self-consistently resolved with the Poisson equation. Temperature dependence of zero-bias resistance area product (RoA) and bias-dependent dynamic resistance of the diode have been analyzed in details to investigate the contribution of dark current mechanisms which reduce the electrical performances of the diode.

An Electrochemical Nitrite Sensor Based on a Multilayer Film of Polyoxometalate

In this work, we have developed an electrochemical sensor for nitrite detection, based on a polyoxometalate (POM) namely mono-lacunary keggin anion [SiW11O39]8﹣ cited as (SiW11). Electrochemical characterization of SiW11 shows two-step reduction processes, with formal potentials of ﹣0.5 V (I) and ﹣0.68 V (II). Oppositely charged polyelectrolyte (poly (allylamine hydrochloride) (PAH)) and (SiW11) were assembled alternately to modify glassy carbon electrode. The electrochemical behavior of the modified electrode was studied in detail using cyclic voltammetry (CV). The results showed that SiW11/PAH/GC electrode present good electrocatalytic activity for the reduction of nitrite. The sensor showed a dynamic range from 100 μM to 3.6 mMof nitrite and no interference from other classical anions. Experimental factors that affect electron-transfer rate in these films, such as pH effect and layers number, were systematically analyzed.

Electrical Analysis of Indium Deep Levels Effects on Kink Phenomena of Silicon NMOSFETs

Several methods of characterization of trap levels like I-V, C-V and transient spectroscopy (DLTS) were used to determine the accurate values of the activation energies of traps present in N+P junctions obtained after retrograde profile implantation of indium and boron on silicon. Four main traps located at Ev + 0.15 eV, Ev + 0.21 eV, Ev + 0.28 eV and Ev + 0.46 eV are reported. Shallow levels are also calculated from I-V characteristics. Concurrently, indium channel doped NMOSFETs are investigated showing the kink phenomenon. In order to discuss the relationship between the kink effect and the active indium trap level situated at 0.16 eV, the transient effects are studied by varying the integration time and the temperature. The effects of substrate polarization are also carried out showing the reduction of the kink with the bulk positive polarization.

Study of Two One-Dimensional Multi Tunnel Junctions Arrays Structures by SIMON

Multi Tunnel Junctions (MTJs) have attracted much attention recently in the fields of Single-Electron Transistor (SET) and Single-Electron Memory (SEM). In this paper, we investigate a nano-device structure using a two one dimensional array MTJs connected to the basic Single Electron Circuits, in order to analyze the impact of physical parameters on the performances and application of this structure. The device generates can operate at room temperature. The simulation of single-electron circuit demonstrates with Monte Carlo simulator, SIMON.

New Model for Drain and Gate Current of Single-Electron Transistor at High Temperature

We propose a novel analytical model to describe the drain-source current as well as gate-source of single-electron transistors (SETs) at high temperature. Our model consists on summing the tunnel current and thermionic contribution. This model will be compared with another model.

Structural, Morphological, Optical and Electrical Properties of Zn_(1-x)Cd_xO Solid Solution Grown on <i>a</i>- and <i>r</i>-Plane Sapphire Substrate by MOCV

Zn(1-x)CdxO films have been grown on (a-plane) and (r-plane) sapphire substrate by metal organic chemical vapor deposition. A maximum cadmium incorporation of 8.5% and 11.2% has been respectively determined for films deposited on a- and r-plane sapphire. The optical transmission spectra and energy band-gap equation established by Makino et al. were used to estimate the cadmium mole fraction of the solid solutions. Structural, morphological and optical properties of these films were examined using high resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM) and room and low temperature photoluminescence (Pl) as Cd incorporation and employed substrate. X-ray diffraction study revealed that all films had wurtzite phase but solid solution grown on a-plane sapphire are polycrystalline with a preferred orientation along the [0001] direction and a-plane film are epitaxially grown on r-plane sapphire. AFM image show significant differences between morphologies depending on orientation sapphire substrate but no significant differences on surface roughness have been found. The near band-edge photoluminescence emission shifts gradually to lower energies as Cd is incorporated and reaches 2.916 eV for the highest Cd content (11.2%) at low temperature (20 K). The room temperature hall mobility decreases with the Cd incorporation but it is larger for Zn(1-x)CdxO grown on r-plane sapphire.

RPL-Based IoT Networks under Decreased Rank Attack:Performance Analysis in Static and Mobile Environments

The RPL(IPv6 Routing Protocol for Low-Power and Lossy Networks)protocol is essential for efficient communi-cation within the Internet of Things(IoT)ecosystem.Despite its significance,RPL’s susceptibility to attacks remains a concern.This paper presents a comprehensive simulation-based analysis of the RPL protocol’s vulnerability to the decreased rank attack in both static andmobilenetwork environments.We employ the Random Direction Mobility Model(RDM)for mobile scenarios within the Cooja simulator.Our systematic evaluation focuses on critical performance metrics,including Packet Delivery Ratio(PDR),Average End to End Delay(AE2ED),throughput,Expected Transmission Count(ETX),and Average Power Consumption(APC).Our findings illuminate the disruptive impact of this attack on the routing hierarchy,resulting in decreased PDR and throughput,increased AE2ED,ETX,and APC.These results underscore the urgent need for robust security measures to protect RPL-based IoT networks.Furthermore,our study emphasizes the exacerbated impact of the attack in mobile scenarios,highlighting the evolving security requirements of IoT networks.

The Impact of Network Topologies and Radio Duty Cycle Mechanisms on the RPL Routing Protocol Power Consumption

The Internet of Things(IoT)has witnessed a significant surge in adoption,particularly through the utilization of Wireless Sensor Networks(WSNs),which comprise small internet-connected devices.These deployments span various environments and offer a multitude of benefits.However,the widespread use of battery-powered devices introduces challenges due to their limited hardware resources and communication capabilities.In response to this,the Internet Engineering Task Force(IETF)has developed the IPv6 Routing Protocol for Low-power and Lossy Networks(RPL)to address the unique requirements of such networks.Recognizing the critical role of RPL in maintaining high performance,this paper proposes a novel approach to optimizing power consumption.Specifically,it introduces a developed sensor motes topology integrated with a Radio Duty Cycling(RDC)mechanism aimed at minimizing power usage.Through rigorous analysis,the paper evaluates the power efficiency of this approach through several simulations conducted across different network topologies,including random,linear,tree,and elliptical topologies.Additionally,three distinct RDC mechanisms—CXMAC,ContikiMAC,and NullRDC—are investigated to assess their impact on power consumption.The findings of the study,based on a comprehensive and deep analysis of the simulated results,highlight the efficiency of ContikiMAC in power conservation.This research contributes valuable insights into enhancing the energy efficiency of RPL-based IoT networks,ultimately facilitating their widespread deployment and usability in diverse environments.

A Secure Hardware Implementation for Elliptic Curve Digital Signature Algorithm

Since the end of the 1990s,cryptosystems implemented on smart cards have had to deal with two main categories of attacks:side-channel attacks and fault injection attacks.Countermeasures have been developed and validated against these two types of attacks,taking into account a well-defined attacker model.This work focuses on small vulnerabilities and countermeasures related to the Elliptic Curve Digital Signature Algorithm(ECDSA)algorithm.The work done in this paper focuses on protecting the ECDSA algorithm against fault-injection attacks.More precisely,we are interested in the countermeasures of scalar multiplication in the body of the elliptic curves to protect against attacks concerning only a few bits of secret may be sufficient to recover the private key.ECDSA can be implemented in different ways,in software or via dedicated hardware or a mix of both.Many different architectures are therefore possible to implement an ECDSA-based system.For this reason,this work focuses mainly on the hardware implementation of the digital signature ECDSA.In addition,the proposed ECDSA architecture with and without fault detection for the scalar multiplication have been implemented on Xilinxfield programmable gate arrays(FPGA)platform(Virtex-5).Our implementation results have been compared and discussed.Our area,frequency,area overhead and frequency degradation have been compared and it is shown that the proposed architecture of ECDSA with fault detection for the scalar multiplication allows a trade-off between the hardware overhead and the security of the ECDSA.

Adsorption of rare earth elements onto diatomite M45:Experimental investigations and modeling with statistical physics theory

The separation of rare earth elements using diatomite M45 from aqueous solutions was studied.The experimental isotherms for the adsorption of trivalent lanthanum,cerium,and neodymium cations on this adsorbent were quantified under strongly acidic conditions(pH 2)at 298-328 K.The adsorption equilibria of these earth elements were analyzed using two statistical physics models(homogeneous and heterogeneous monolayer models).The results show that the adsorption of these ions implies a multiionic mechanism,which is exothermic.Si-containing functional groups are responsible for the adsorption of these rare-earth elements on the diatomite surface.A heterogeneous statistical physics model confirms that two Si-based functional groups participate in the separation of these cations.The calculated adsorption capacities at saturation follow the order:neodymium>cerium>lanthanum.Calculated interaction energies range from 28600 to 40100 J/mol,indicating physical adsorption on diatomite M45.This study demonstrates that diatomite M45 is a promising separation medium that can be used for the recovery of REEs dissolved in aqueous solutions via adsorption.

On the sub-mixed fractional Brownian motion

Let {S t H, t ≥ 0） be a linear combination of a Brownian motion and an independent sub-fractional Brownian motion with Hurst index 0 〈 H 〈 1. Its main properties are studied. They suggest that SH lies between the sub-fractional Brownian motion and the mixed fractional Brownian motion. We also determine the values of H for which SH is not a semi-martingale.

New Biobased Polyurethane Materials from Modified Vegetable Oil

Bio-based polyurethanes(PUs)have been occurred a large attention nowadays.It was found to be an alternative to the petrochemical based materials to the fact of their weak environmental influence,availability,good price and biodegradability.In addition,the nature shows several bio-derived compounds as raw materials for the synthesis of polyols,including the vegetable oils,polyphenol,terpene,and other bio-renewable sources.With the aim to develop a new family of biobased polyurethanes(PUs)via vegetable oils,the elaboration of new Jojoba-based PUs was performed by catalyst-free polycondensation reaction of a synthesized Jojoba diol with various diisocyanates such us toluene diisocyanate(TDI)and isophorone diisocyanate(IPDI).All the compounds were characterized by FTIR and NMR spectroscopies,and their properties were determined by gel permeation chromatography,differential scanning calorimetry and thermogravimetric analysis.The obtained results show renewable vegetable oils-based PUs materials can be preparing using a new environmentally ways and giving various good properties performances.

Design of novel circular lattice photonic crystal fiber suitable for transporting 48 OAM modes

In this paper,we propose and numerically investigate a novel circular lattice photonic crystal fiber(CL-PCF)using controllable GeO_(2) doped silica,suitable for modes carrying quantized orbital angular momentum(OAM).Large effective index separations between 25 supported vector modes(≥10^(-4))are confirmed over large bandwidth(C+L bands)leading to 48 OAM modes bearing information.The simulations show that the modes in the proposed CLPCF have good features including low and flat dispersion(within 51.82 ps/km/nm),low confinement loss(lower than 0.002 d B/m),high effective mode area(88.5μm^(2))and low nonlinearity(1.22 W^(-1)·km^(-1)).These promising results show that the proposed CL-PCF could be an arguably candidate in fiber-based OAM multiplexing or other applications using OAM states.