Electrochemical behavior of a new <Emphasis Type="Italic">s</Emphasis>-triazine-based dendrimer

The electrochemical behavior of a new G-2-s-triazine-based dendrimer, 2,4,6-tris-{4-{4,6-bis-{4-{4,6-bis-[(1S,2S)-1,3-dihydroxy-1-(4-nitrophenyl)-prop-2-ylamino]-s-triazin-2-yl}-piperazin-1-yl}-s-triazin-2-yl}-piperazin-1-yl}-s-triazine, (I), was studied in dimethylsulfoxide solution by cyclic voltammetry, on platinum and graphite electrodes. The electrochemical properties of I were compared with that of one of its precursor, N-{4,6-bis{4-{4,6-bis[(1S,2S)-1,3-dihydroxy-1-(4-nitrophenyl)-prop-2-ylamino]-s-triazin-2-yl}-piperazin-1-yl}-triazin-2-yl}-piperazine), (II), together with that of the starting material, (1S,2S)-2-amino-1-(4-nitrophenyl)-propane-1,3-diol (“p-nitrophenylserinol”), (III).     

Reliability of degrading dynamic systems

Methods are developed for finding the reliability of Daniels systems and plates with cracks that are subjected to dynamic random load processes. Reliability of these systems is defined, respectively, as the probability that there is at least an unfailed fiber and crack length does not exceed a critical value during a reference period. Properties of conditional mean crossing rates and diffusion models are used in analysis.     

Comparison of the Switching Behaviour of Electrodeposited Silver and Silver-Cadmium Alloys Contact Materials

The quality of contact materials depends on their physical properties, such as density, hardness and conductivity, as well as on their contact characteristics (contact resistance, weldability and erosion). An instrumentation system is described here, which measures the most important attributes of contact materials simultaneously. The measurements are taken under simulated service conditions. The rated electrical current is passed through contacts of reference and test materials in a relay controlled by an electronic module; the contact resistance, weldability and arc erosion are monitored. In this system two pairs of contact elements—one pair made of the test material, and the other made of reference material—are compared. The relay is an actual electrical device wich would use the test material as its contact elements in normal operation. The test material is silver-cadmium alloy electrodeposited from an iodide bath; and the reference material is electrodeposited silver from a cyanide bath.     

The Small Project Observatory: Visualizing software ecosystems

Software evolution research has focused mostly on analyzing the evolution of single software systems. However, it is rarely the case that a project exists as standalone, independent of others. Rather, projects exist in parallel within larger contexts in companies, research groups or even the open-source communities. We call these contexts software ecosystems. In this paper, we present the Small Project Observatory, a prototype tool which aims to support the analysis of software ecosystems through interactive visualization and exploration. We present a case study of exploring an ecosystem using our tool, we describe the architecture of the tool, and we distill lessons learned during the tool-building experience.     

Solidification of a PEG 1500-epoxy nanocomposite around a horizontal pipe

A PCM-epoxy phase change material composite (polyethylene glycol 1500-epoxy) was developed as heat storage building element for houses with low energy consumption. The PCM component, polyethylene glycol 1500, was integrated in an epoxy matrix, and presents a phase change interval of 34-42 °C and an enthalpy of solidification of 103.411 kJ/kg. Experiments on solidification were conducted using a Plexiglas test cell filled with the PEG 1500-epoxy nanocomposite material (P15-E) for further implementation of this material in buildings. The forwarded solidification model assumes negligible convection in the liquid region and predicts the time for radial formation of two regions: a mushy-zone and a solid, annular one around the pipe during solidification. The heat transfer during solidification can be also characterized by the time evolution of both liquid and solid radial fronts. The model was analytically solved using Megerlin approximation concerning “solidification with mushy zone”, with the third order condition at the external frontier. The experimental values are in agreement with the calculated theoretical curves.     

THE ENERGETIC STABILITY OF TORI AND SINGLE-WALL TUBES

Tessellated tori, generated here from square-like tiled lattices, are closely related to cylinders and capped tubes. This way of building them enables the orientation of their bonds, and so the geometric proportions of the torus, to be specified for molecular mechanics calculations and, along with their transformation into capped tubes this is illustrated and discussed in the light of their energetic stability.     

FEM modelling and experimental characterization of microbeams in presence of residual stress

Out-of-plane bending tests are here used to experimentally validate some numerical models of microbeams actuated by the electric field. Out-of-plane bending microcantilevers and clamped–clamped microbeams often suffer the presence of residual strain and stress, respectively, which affect their static and dynamic behaviour and pull-in voltage. In case of microcantilever an accurate modelling has to include the effect of an initial curvature due to microfabrication process, while in double clamped microbeams constraints may impose a pre-loading caused by a tensile stress. So-called geometrical nonlinearity sometimes occurs, when microcantilever exhibits large displacement, or because of the mechanical coupling between axial and flexural behaviours in double clamped microbeams. Modelling this kind of nonlinearity is an additional goal of this study. Experiments demonstrated a good agreement with results of FEM approaches proposed. In the case of microbridges numerical models are used to identify the residual stress. A reverse analysis is implemented, the axial pre-stress is calculated by means of the measured pull-in voltage.     

Quantum circuit’s reliability assessment with VHDL-based simulated fault injection

This paper presents a VHDL-based simulated fault injection (SFI) methodology for quantum circuits. The main objective is to attain a high error modeling capability at a technology independent level. For this purpose, gate level simulation models for quantum circuits have been developed using VHDL. The proposed methodology relies on specific techniques inspired from the simulated fault injection techniques developed for classical CMOS circuits: saboteurs and mutants. In order to perform the simulation campaigns, a library of quantum gates and simulated fault injection components has been developed. The simulation results show that a wide range of quantum faults and error models has been addressed. Furthermore, a comparison between the two SFI techniques is presented.