Reliability approach for vehicle safety components

Owing to ‘producer's liability for defective products’ the safety-related components of vehicles have to be designed, tested and manufactured in an appropriate way. Some considerations are presented about useful procedures in design and testing of safety parts which may help to reach the required high reliability and minimize risks. Problem areas are indicated which need more research. In future the reliability approach in automotive industries will come closer to the standards in aeronautics. This trend is accelerated by the rapid use of electronics in automobiles.     

Thermodynamic behaviour of an air-conditioning system employing combined evaporative-water and air coolers

The performance of an open absorption-system, energized by low-grade heat such as insolation and/or waste heat, has been investigated. This combined evaporative cooler (CEC) [i.e. an indirect evaporative cooler (IEC) together with a direct evaporative-cooler (DEC)] was used to cool the air. A computer simulation of the cooling cycle was devised, so that the performance characteristics of the system could be predicted for a range of operating conditions: the influences of various design-parameters on the coefficient of performance (COP) were also evaluated. The COP of the CEC system was at least 20% greater than those achieved when employing either the IEC or DEC systems alone.     

Conductive Anodic Filament (CAF) Formation Part I: the Influence of Water-Soluble Flux on Its Formation

Conductive anodic filament (CAF) formation has been studied for a number of years, but the mechanism of its formation has not previously been defined. In 2002, Ready identified CAF as atacamite, Cu₂(OH)₃Cl. Electrochemical studies have shown that both CuCl and CuCl₂⁻ participate in the formation of Cu₂(OH)₃Cl, with the predominating species being CuCl. This paper proposes a mechanism for CAF formation based on x-ray photoelectron spectroscopy. The data show that CuCl is the precursor to the formation of Cu₂(OH)₃Cl in the presence of oxygen and water. Earlier, Meeker and Lu Valle had proposed that CAF failure is best represented by two competing reactions: the formation of a copper chloride corrosion compound (now identified as Cu₂(OH)₃Cl) and the formation of innocuous trapped chlorine compounds. Since no evidence of any trapped chloride compounds has been found, we propose that the formation of CAF is best represented by a single nonreversible reaction.     

Development and Assessment of a Small‐Scale Wort Filtration Test for the Prediction of Beer Filtration Efficiency

A Small‐scale Wort rapid Filtration Test (SWIFT) that predicts beer filtration efficiency has been developed. The test is simple, cost effective and correlates with existing beer filtration tests such as beer V_max membrane (Esser test) and diatomaceous earth (Walton filter) tests. SWIFT has an advantage over existing beer filtration tests as it can be easily incorporated into barley quality laboratories utilising excess wort from extract analyses, thus negating the need for additional sample preparation or to ferment and age beer. Furthermore, the test does not rely on expensive equipment or specially trained laboratory technicians. SWIFT, which may also be used to evaluate degassed beer, is a syringe test that utilises a 13 mm diameter 0.45 μm membrane and is negatively influenced by wort viscosity (P<0.05). It is envisaged that SWIFT may be applied by barley breeding programs for the evaluation of progeny lines to provide a better prediction of beer filtration performance than total wort β‐glucan measurements. In addition, maltsters and brewers could use SWIFT to assess malt samples, and provide early warning of potential beer filtration problems during the brewing process.     

Polarization stability of phase-locked arrays of vertical-cavitysurface-emitting lasers

The polarization stability of the fundamental lasing super-mode obtained from coherently coupled arrays of vertical-cavity surface-emitting lasers has been investigated. Various devices have been analyzed and none showed the abrupt change of the polarization direction (flip) often observed in solitary devices. This polarization stability is due to a current independent dichroism of 0.5 GHz     

Long-term spectral stability of singlemode VCSELs

The long-term spectral stability of 780 nm AlGaAs-based vertical-cavity surface-emitting lasers has been investigated. The 28 devices from two different wafers show a thermally induced averaged total spectral shift of 75±9 and 47±7 GHz, respectively     

Autonomic and Decentralized Management of Wireless Access Networks

In this article, we apply autonomic and distributed management principles to wireless access networks. Most interesting is the application of autonomic properties and behaviors including adaptive, aware, and automatic operation in a decentralized setting. In particular, we present a generic and autonomic management architecture for decentralized management of wireless access networks, such as GERAN/UTRAN, E-UTRAN, WiMAX or WLAN. For evaluation purposes, we apply this architecture to the management of a Wireless LAN network, and we evaluate the architecture and some of the autonomic management functions through simulations, a prototype implementation and the setup of a real-world testbed for experimentation with the proposed management approach.     

Focused ion beam (FIB) etching to investigate aluminium-coated polymer laminates subjected to heat and moisture loads

Multilayered aluminium-coated polymer laminates are the common barrier envelopes of vacuum insulation panels used as high performance thermal insulation in building applications. These laminates are made of up to ten distinct layers including three aluminium barrier layers applied by vacuum web coating. During their expected lifetime, which is required to last longer than 20 years, they will be subjected to heat and moisture loads induced by internal and external climatic conditions. This paper investigates the deteriorations of the barrier function of two different laminates commonly used for the production of vacuum insulation panels. These were subjected to well defined exterior heat and moisture loads and investigated by means of focused ion beam etching. Delamination of the polyurethane adhesive layers and stress induced relaxation in them are made visible. Oxidised aluminium layers are also detected by this method.