我的目光，我的前方——塑料产业链知名企业总裁专访：水·环保·塑料工业

2008年，金融风暴席卷全球。一年过去了，仍让人感觉惊魂未定。这场全球性危机给跨国企业、石化行业及其下游兼加工行业造成了不小的负面影响，导致大量工厂破产、关停和裁员，损失惨重。     

Optical Fiber Accelerometer System for Structural Dynamic Monitoring

In this study, the implementation of an optical accelerometer unit based on fiber Bragg gratings, suitable to monitor structures with frequencies up to 45 Hz, is reported. The developed optical system was used to estimate the structure eigenfrequencies of a steel footbridge, with a total length of 300 m, over the Sao Pedro Creek, located at University of Aveiro Campus, in Portugal. The acceleration records measured with this solution are compared with those obtained by traditional commercial electronic devices, revealing a root-mean-square error of 2.53 times 10^-5 G.     

A Log-Domain CMOS Transcapacitor: Design, Analysis and Applications

We present in this paper the CMOS implementation of a transcapacitor working in the log-domain. This circuit integrates a differential input current into an output pseudo-voltage, which is similar to the compressed voltage used as the internal variable in companding filters. This log-domain transcapacitor is compatible with pseudo-conductances implemented with a single transistor. The pseudo-transcapacitor circuit is analyzed and a collection of log-domain reactive components and small circuits using it is proposed.     

Chemical applications of near-field scanning optical microscopy: Surface and near-surface chemical imaging with conventional near-field optical probes and externally illuminated chemically active ion sensors

Near-field optics using force sensing cantilevered optical fibers and micropipettes is used to investigate the chemical distribution of protein complexing dyes in chromosomes and the sensing and chemical imaging of surfaces and nearsurface regions. These results are put in the context of what presently can be considered as a broad picture of near-field optical chemical applications.     

Efficient Algorithm for the Constrained Two-dimensional Cutting Stock Problem

This paper considers the constrained two-dimensional cutting stock problem. Some properties of the problem are derived leading to the development of a new algorithm, which uses a very efficient branching strategy for the solution of this problem. This strategy enables the early rejection of partial solutions that cannot lead to optimality. Computational results are given and compared with those produced by a leading alternative method. These results show that the new algorithm is far superior in terms of the computer time needed to solve such problems.     

Microstructure and rheological behavior of hypereutectic semi-solid Al–Si alloy under low shear rates compression test

Permanent mold cast cylindrical samples were reprocessed to form semi-solid billets of A390 Al–Si alloy, employing a thixocasting method. The billets were reheated to predetermined mushy zone temperatures and held isothermally during parallel plate compression tests. The deformation behavior of the billets was measured at different applied pressures, and fraction solids determined by the preheating temperature. The calculated viscosities confirmed pseudoplastic behavior of the semi-solid alloys and were correlated to the solid fraction and shear rate to illustrate the effect of metallurgical and process parameters on the viscosity and the consequent rheological behavior of these alloys.     

Application of the integrated reliability analysis system (IRAS)

This paper introduces a UNIX-based computer aided reliability assessment system, IRAS, which was developed in the Brite/Euram project BE-4250. It utilises fault propagation models for automatic generation of Fault Trees, Cause–Consequence Diagrams and FMECA. Therefore, it has the following features: a Model Builder which allows the creation of the fault propagation models in a hierarchical manner; a Fault Tree Analysis module that is able to generate Fault Trees on demand and to extract minimal cut sets; an FMECA module that is able to search for and group effects of basic events according to their criticality, severity and probability; a Real Time Fault Location (RTFL) module that enables the fast detection of the most probable cause(s) of system malfunction based on information available from sensors and/or operator. This paper describes the underlying ideas and procedures of IRAS and shows an example application to a Hot Strip Steel Mill.     

The Precautionary Principle in a World of Digital Dependencies

As organizations become deperimeterized, a new paradigm in software engineering ethics becomes necessary. We can no longer rely on an ethics of consequences, but might instead rely on the precautionary principle, which lets software engineers focus on creating a more extensive moral framework.     

Improvement of the output power in TWTs by harmonic injection

The possibility of improving the fundamental output power of a traveling wave tube (TWT) using second harmonic injection is presented in this paper with theoretical, numerical, and experimental approaches. A calculus of the energy extracted from an electron beam subjected to a bi-harmonic field is presented in the low-gain regime, and it shows how the shape of the field can increase the fundamental extracted power. The phase difference between the fundamental and harmonic waves appears to be a key parameter for harmonic injection. The large signal code TUBH from Thales Electron Devices is used to simulate a TWT where both the fundamental and harmonic waves travel with the same velocity and the same growth rate. Harmonic injection simulations show that the fundamental output power is optimized when the total energy extracted from the beam is maximized, and the fundamental wave is favored to the detriment of the harmonic wave. A three-dimensional version of the code, called MVTRAD, is used to simulate an industrial TWT manufactured at Thales. Experimental measurements on this TWT completed this paper, showing a significant increase of fundamental output power with harmonic injection with up to 86% of additional power at 5 GHz.     

Phase Equilibria in the Al-Co-Ni Alloy System

The phase equilibria in the Ni-Co rich region (<50 at.%Al) of the Al-Co-Ni system were studied experimentally for two isothermal sections at 1100 and 800 °C. Metallography, energy dispersive spectroscopy, hardness and x-ray diffraction were used for characterization and determination of γ, γ′ and β phases within the ternary system. Phase boundaries in the isothermal sections and a partial liquidus projection are modified compared to previously published work. Comparison is made to the isothermal sections computed using Thermo-Calc and the TCNI8 database. No definitive experimental evidence corroborating the predicted existence of a Nishizawa horn was obtained.