Model interoperability via Model Driven Development

Among the factors that contribute to the inherent complexity of the software development process is the gap between the design and the formal analysis domains. Software design is often considered a human oriented task while the analysis phase draws on formal representation and mathematical foundations. An example of this dichotomy is the use of UML for the software design phase and Petri Nets for the analysis; a separation of concerns that leads to the creation of heterogeneous models. Although UML is widely accepted as a language that can be used to model the structural and behavioural aspects of a system, its lack of mathematical foundations is seen as a serious impediment to rigorous analysis. Petri Nets on the other hand have a strong mathematical basis that are well suited for formal analysis; they lack however the appeal and the ease-of-use of UML. A pressing concern for software developers is how to bridge the gap between these domains and allow for model interoperability and the integration of different toolsets across them, and thus reduce the complexity of the software development process. The aim of this paper is to present a Model Driven Development (MDD) model transformation which supports a seamless transition between UML and Petri Nets. This is achieved by model interoperability from UML Sequence Diagrams to Petri Nets and supported by tool integration. The model transformation framework allows a software system to be designed in terms of UML Sequence Diagrams and subjected to formal analysis by taking advantage of the strong mathematical framework of Petri Nets. The behaviour of a Personal Area Network will be used to illustrate the proposed approach and to highlight model interoperability and tool integration through the design, the transformation and the analysis phases.     

Anti-Corrosive Properties of (1-benzyl-1H-1,2,3-triazol-4-yl) Methanol on Mild Steel Corrosion in Hydrochloric Acid Solution: Experimental and Theoretical Evidences

Protection of Metals and Physical Chemistry of Surfaces - The corrosion inhibitory effect of (1-benzyl-1H-1,2,3-triazol-4-yl) methanol (BTM) for mild steel in 1 M HCl at (298–328 K) was...     

Output feedback control of supercapacitors parallel charging system for EV applications: Theoretical design and experimental validation

In this paper, the problem of controlling parallel charging system with supercapacitors for electric vehicle applications is considered. When the vehicle parks at the station, the charging process of supercapacitors needs to be completed in less than 30 seconds. The control objective is then to tightly regulate the supercapacitors state of charge (SOC) to a given reference constant and to ensure an adequate current sharing between different parallel chargers. Indeed, the current sharing is a critical issue for parallel charging system with supercapacitors, which is a nonlinear system with control inputs constraints. Besides, the SOC depends on the supercapacitors internal voltage, which is not accessible for measurement. Therefore, based on a large‐signal model of the parallel‐chargers‐supercapacitors system, an output feedback controller (combining a state observer and a nonlinear control laws) is designed. The controller is formally shown to meet all objectives, namely, closed‐loop stability, SOC reference tracking, and equal current sharing. The effectiveness of the proposed output feedback controller approach is verified both by simulation and by experimental tests.     

Physical and photo-electrochemical characterizations of α-Fe2O3. Application for hydrogen production

The optical, electrical and photo-electrochemical properties of dense hematite α-Fe₂O₃ have been studied for the photo-catalytic hydrogen production. The band gap was evaluated at 1.96 eV from the diffuse reflectance spectrum and the transition is directly allowed; further indirect transition occurs at 2.04 eV. The oxygen deficiency permits the altering of the transport properties and the oxide exhibits n type behavior with activation energy of 0.11 eV. α-Fe₂O₃ is found to be photo-electrochemically active. The flat band potential V_fb (−0.51 V_SCE) and the density N_D (19.12 × 10¹⁹ cm⁻³) were obtained respectively by extrapolating the linear part to C⁻² = 0 and the slope of the Mott–Schottky plot. The complex impedance pattern is circular in the high frequency region followed by a straight line in the low frequency one, a behavior attributed to the Warburg ionic diffusion. The conduction band edge (−0.62 V_SCE) lies below the H₂O/H₂ level (−0.50 V_SCE) and Fe₂O₃ offers the possibility to be used as hydrogen photocathode. The best activity was obtained in SO₃²⁻ (0.5 M, pH 13.8) solution with a rate evolution of 6 ml (g catalyst)⁻¹ min⁻¹.     

XRD evidence of macroscopic composition inhomogeneities in the graphite–lithium electrode

In situ and ex situ X-ray diffraction (XRD) measurements were carried out on lithiated graphite electrodes at different states of charge. Data were collected from both sides of electrode. We found macroscopic inhomogeneities in the lithium concentration along the electrode thickness even when the electrode was allowed to rest for 24 h. The electrode side facing the lithium counter electrode in the coin type half-cell displays higher lithium concentration as compared to the side opposed to the XRD window. Residual stage 2 compound is found in the supposedly fully lithiated and fully delithiated electrode. It seems that the differences in the chemical potential between stage 2 and stage 1 is too small to average the lithium composition through chemical diffusion at ambient temperature in reasonable times.     

Algerian Sahara Sand Dunes Characterization

For a possible use of Saharan sands, representative samples were collected and analysed by several physicochemical methods. The results show that quartz (98 %) is the most represented mineral, while the oxides of aluminium, potassium, iron, chromium and manganese probably are included in a clay phase. The granular analysis enabled the determination of uniformity coefficient (CU) and equivalent diameter. On the other hand, a comparison of the Infrared spectrum of the sand (washed and unwashed) was carried out as well as Scanning Electron Microscopy observations and X-Ray analysis.     

Synchronization of Fractional Hyperchaotic Rabinovich Systems via Linear and Nonlinear Control with an Application to Secure Communications

International Journal of Control, Automation and Systems - This paper proposes two approaches for the synchronization of a fractional hyperchaotic Rabinovich master-slave pair. The first approach...     

Mixed convection and entropy production of a hybrid nanofluid in a porous cylindrical enclosure with rotating top wall

A numerical study is carried out to investigate heat transfer and entropy production of a hybrid nanofluid in a porous cylindrical enclosure with a rotating top wall. The bottom wall of the cylinder is taken as hot, the sidewall is adiabatic, except the top wall is considered cold and rotates at an angular velocity (ΩR). The effects of a hybrid nanofluid flow on heat transfer and entropy generation are examined for an aspect ratio (H/R = 1). A FORTRAN program was elaborated for solving the governing equations based on the finite volume method. Good agreement was found when comparing results from this study against published data. Our results are presented for different Reynolds number values (100 ≤ Re ≤ 1500), nanoparticle fraction NP (0 ≤ ϕ ≤ 0.08), Darcy number (10⁻⁴ ≤ Da ≤ 10⁻¹) and porosity of the porous medium (0.2 ≤ ε ≤ 0.99) for Ri = 0.5, 1,5 and 8, where (Ri = Gr/Re2). They reveal that the heat transfer increases with Re, ϕ, Da, Ri, and decreasing ε. The simulation data were used to propose four different correlations for $\overline{\mathit{Nu}}$ and S_tot as Re, Da, Ri, ϕ, and ε.     

Numerical study on the effects of the macropatterned active surfaces on the wall-coated steam methane reformer performances

This paper deals with a numerical study on the steam methane reforming reaction performances into a wall-coated steam methane reformer (WC-SMR), intended to produce hydrogen. In this work a new catalytic pattern, purporting to enhance the WC-SMR efficiency, is proposed. A comparison study is made between the new inter-catalytic layers pattern and a conventional one with a continuous catalytic layer pattern. Both WC-SMR models operate at similar conditions and at the same design parameters, except the catalytic zone length which is monitored by taking into account the inter-catalytic layers spacing or not. Our results show that, by adopting a catalytic surface with an inter-catalytic spacing, the methane conversion could be enhanced and thus the hydrogen production is intensified.