An object based algebra for specifying a fault tolerant software architecture

In this paper we present an algebra of actors extended with mechanisms to model crash failures and their detection. We show how this extended algebra of actors can be successfully used to specify distributed software architectures. The main components of a software architecture can be specified following an object-oriented style and then they can be composed using asynchronous message passing or more complex interaction patterns. This formal specification can be used to show that several requirements of a software system are satisfied at the architectural level despite failures. We illustrate this process by means of a case study: the specification of a software architecture for intelligent agents which supports a fault tolerant anonymous interaction protocol.     

The problem of non-compliant concrete and its influence on the reliability of reinforced concrete columns

The discussion about the fact that the concrete provided by concrete companies for the Brazilian construction sites is not meeting the compressive strength specified in the structural design is growing rapidly. These are the so-called non-compliant concretes. This paper discusses the influence of non-compliance of the compressive strength specified in the design (f_ck) on the structural safety level of reinforced concrete columns. The simulation of the column behavior was carried out by a numerical model based on the finite element method. The nonlinear finite element model used was presented and validated by comparison with experimental results obtained by different researchers. The Monte Carlo method was adopted for the determination of the reliability index (β) of reinforced concrete columns. The results show that many factors should be considered in the assessment of the actual damage caused by a non-compliant concrete to the column safety level.     

Optimality criteria for materials with nonlinear behaviour: application to beams in bending

Structural optimization problems involving materials with nonlinear behaviour are dealt with and constraints on displacements are taken into account. The optimality criterion for such problems is shown to involve an adjoint problem and a dual material, whose constitutive law is linear, depending on the stress state of the actual structure. Beams in bending are studied and analytical and numerical methods of solution are discussed.     

Servo-fluid-elastic modeling of contactless levitated adaptive secondary mirrors

The paper develops a comprehensive approach for the servo-fluid-elastic modeling of electromagnetically levitated secondary adaptive mirrors. The system modeling includes the mirror structural dynamics model, its interaction with the fluid film interposed between the mirror and its reference backplate and disturbances due to local air turbulence. The accuracy of the proposed fluid dynamic model is assessed by comparing it with a significant sample of high fidelity 3D Navier?CStokes analyses. The simulation tool is then used to demonstrate the effectiveness and robustness of a recently proposed control, based on a system dynamics cancellation and an iterated steady state feedforward contribution. The simulations clearly highlights the improvements achievable implementing the new control scheme.     

Quantitative optical analysis of filler dispersion degree in MWCNT–epoxy nanocomposite

Recently developed methodology of quantitative analysis based on optical analysis of filler particles’ area distributions is applied now to estimate the dispersion efficiency of multiwall carbon nanotubes in nanocomposite prepared by solution intercalation method. Experimental parameters of dispersing (temperature, duration and power level of ultrasonication) were optimized and the most effective experimental procedure was determined. The methodology of determination of dispersion parameter is proved by indirect method of light transmittance experiments. The nanocomposite specimens having lower dispersion parameter represented the highest transmittance over the nanocomposite specimens.     

Viscoelastic Properties of Tarocco Orange Fruit

In this work, the rheometrical behaviour of Tarocco orange fruit was assessed via stress–relaxation testing under constant engineering strain (ε _z) in the range of 5–20% of the initial fruit height, each test being prolonged for 15 min and replicated 20 times. The time course of the experimental dimensionless relaxation modulus (G*) was typical of a viscoelastic solid and was reconstructed by considering two Maxwell elements in parallel to an elastic spring element. In a more restricted ε _z range (i.e. 5–10%), the dimensionless viscoelastic constants (A _i) were found to be approximately constant, the elastic component responsible for the equilibrium residual stress representing about 42% of the initial relaxation modulus. After any orange fruit had been submitted to stress–relaxation testing and decompressed for 5 min, it exhibited a practically negligible mass loss (0.04 ± 0.03%) and a permanent volume contraction rising from 1.7 ± 1.0% to 3.0 ± 0.9% as ε _z was increased from 5% to 10%. Thus, by tasting the orange fruit firmness at ε _z ≤5%, fruit response, being of the viscoelastic type, is expected to give rise to nearly irrelevant deformations.     

Theognis of Megara and the Divine Creating Power in the Framework of Semiotic Textology: An Application of János Sándor Pet?fi’s Theory to Archaic Greek Literature

This paper is a demonstration of an application of Semiotic Textology to a limited case study. The main aspects of Semiotic Textology, the theory elaborated by Pet?fi, are presented; secondly the linguistic aspects of the interpretation of lines 133?C134 of the Theognis of Megara??s poem, analysed in the framework of said theory, are presented. All the relevant syntactic, semantic, pragmatic information involved in text processing have been considered. Through fixed steps, it is shown that text processing is not exclusively a grammatical activity, because within a theoretical interpretation an Interpreter needs a number of contextual hypotheses, in order to understand the author??s ontology.     

A novel coaxial loop resonator for wireless power transfer

We present a novel resonator, based on a coaxial cable structure, suitable for wireless power transfer (WPT) applications. Its advantages are compactness, ease of manufacture, and low cost. WPT resonators generally operate in the HF, LF bands, using magnetic field coupling and a lumped capacitance for achieving the sought resonance. In our structure, the electric field is primarily confined inside the coaxial cable, whereas the magnetic field is generated by the currents flowing on the external conductors. The article describes the resonator structure, illustrates its design procedure, and discusses quality factor contributions. A few resonators with Q higher than 900, operating around 30 MHz, have been built, simulated, and measured confirming the validity of the proposed approach. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE , 2012.