Mixed-Signal Circuit Classification in a Pseudo-Random Testing Scheme

Pseudo-random testing techniques for mixed-signal circuits offer several advantages compared to explicit time-domain and frequency-domain test methods, especially in a BIST structure. To fully exploit these advantages a suitable choice of the pseudo-random input parameters should be done and an investigation on the accuracy of the circuit response samples needed to reduce the risk of misclassification should be carried out. Here these issues have been addressed for a testing scheme based on the estimation of the impulse response of the device under test (DUT) by means of input-output cross-correlation. Moreover, new acceptance criteria for the DUT are suggested which solve some ambiguity problems arising if the classification of the DUT as good or bad is based on a few samples of the cross-correlation function. Examples of application of the proposed techniques to real cases are also shown in order to assess the impact of the measurement system inaccuracies on the reliability of the test.     

Satisfying quality requirements in the design of a partition‐based,distributed stock trading system

Although quality requirements (QRs) have become a major drive in today's software development, there have been very few real‐world examples in the literature that demonstrate how to meet these requirements. This paper presents such an example. Specifically, the paper describes the design of a partition‐based distributed stock trading service system that satisfies a set of QRs related to resource utilization, performance, scalability and availability. The paper evaluates this design through detailed experiments and discusses some design alternatives and the lessons learned. Central to this design are a static load distribution strategy and a dynamic load balancing strategy. The first strategy is to achieve an initial balanced workload on the system's server cluster during the system initialization time, whereas the second strategy is to maintain this balanced workload throughout the system execution time. Together, these two strategies work in unison to ensure that the server resources are efficiently utilized; the user requests are processed with the required speed; the application is partitioned with sufficient room to scale; and the system is highly available. Copyright © 2011 John Wiley & Sons, Ltd.     

Creep of cold-worked Zry-4 at 673 K

Creep data, at 673 K, up to times of about 400 h and stresses between 117.6 and 264.7 MPa, in flat specimens of cold-worked Zry-4, are reported. When viewed in a σ-/.ε diagram, the data can be represented by Hart's equation of state $\text{/.ε = /.ε}{}^1\text{[ln(σ}{}^1\text{/σ)]}{}^{\mathrm{<mtext>?1</mtext><mtext>\lambda </mtext>}}$, where σ¹ and /.ε¹ are related to the plastic strain and λ is a constant, with a value similar to that obtained by measurements of the stress-relaxation in bending of the same material and at the same temperature. No distinction is made between primary and steady-state creep, indicating that the same mechanism is controlling the plastic deformation in both regions. The apparent activation energy was found to be independent of stress with a value close to that for self diffusion.     

Analysis of network structure formed in styrene–butadiene rubber cured with sulfur/TBBS system

Several styrene–butadiene rubber (SBR) compounds were prepared with different cure systems based on sulfur and TBBS (N‐t‐butyl‐2‐benzothiazole sulfenamide), varying the amount of sulfur and accelerator between 0.5 and 2.5 phr in the formulation. Torque curves, measured with a moving die rheometer at temperatures at 433 K, were used to characterize the vulcanization. The time to achieve the maximum torque, t_100%, was evaluated for each sample, and this time was set to vulcanize sheets at 433 K. The density and type of elastically active crosslinks of each cured sample were evaluated by means of swelling measurements and were related to the vulcanizing system. Finally, the rheometer data were analyzed considering the network structure formed during vulcanization. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1105–1112, 2007     

A parametric study on supersonic/hypersonic flutter behavior of aero-thermo-elastic geometrically imperfect curved skin panel

In this paper, the effect of the system parameters on the flutter of a curved skin panel forced by a supersonic/hypersonic unsteady flow is numerically investigated. The aeroelastic model investigated includes the third-order piston theory aerodynamics for modeling the flow-induced forces and the Von Kármán non-linear strain-displacement relation in conjunction with the Kirchhoff plate hypothesis for the panel structural modeling. Structural non-linearities are considered and are due to the non-linear coupling between out-of-plane bending and in-plane stretching. The effects of thermal degradation and Kelvin??s model of structural damping independent on time and temperature are also considered. The aero-thermo-elastic governing equations are developed from the geometrically imperfect non-linear theory of infinitely long two-dimensional curved panels. Computational analysis and discussion of the finding along with pertinent conclusions are presented.     

Preparation of Pb(Ti,Zr)O3/RuO2 multilayers in situ by pulsed laser ablation deposition

Abstract

RuO₂/PbZr_0.52Ti_0.48O₃ multilayers have been prepared by pulsed laser deposition and characterised by Grazing Incident Angle Bragg Diffraction and scanning electron microscopy. The results are correlated with the different deposition conditions and post-growth thermal annealing. The structure of the paraelectric pyrochlore phase (Pb₂(Zr,Ti)₂O₆) and its stability relative to the ferroelectric perovskite is discussed.     

Analysis of the variation of molecular parameters of NR during vulcanization in the frame of the conformational tube model

The network structure of natural rubber (NR) achieved during vulcanization was analyzed using the model of rubber elasticity based on the tube concept, applied to the treatment of the stress-strain measurements. This theory allows the separation of constraint and crosslink contributions. Also, network parameters can be calculated. The crosslink level of the material was changed using different times and temperatures of cure. The change in the molecular parameters of the model with the degree of cure was estimated. The present research is useful for the precise determination of the chemical crosslink density of the NR network. The values were compared with those obtained by means of equilibrium volume swelling measurement. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1085–1092, 1997     

Analysis of variation of molecular parameters of natural rubber during vulcanization in conformational tube model. II. Influence of sulfur/accelerator ratio

A natural rubber (NR) with a conventional sulfur cure system and a ratio of sulfur/accelerator (Ω) equal to 3 was investigated. The network structure of the NR during vulcanization was analyzed using a model of rubber elasticity based on the tube concept, which was applied to the treatment of the stress–strain measurements. The influence of cure time and temperature on the chemical crosslinks density was analyzed. The values were compared with those obtained by means of an equilibrium volume swelling measurement. The differences between samples of NR cured with Ω = 3 and 1.5 were analyzed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2747–2755, 1999     

Influence of carbon black dispersion on the thermal diffusivity of an SBR vulcanizate

There are few investigations of the influence of filler dispersion on the thermal diffusivity of carbon black rubber compounds. In this article, experimental results of a cured styrene–butadiene rubber (SBR) compound are presented in the range of temperatures between 210 and 350 K at four levels of dispersion obtained in a laboratory mill. The results of thermal diffusivity measurements are discussed in the frame of competitive mechanisms appearing during mixing and involving the breakdown of agglomerates into aggregates and particles in the rubber matrix. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1379–1385, 1999