Reliability aspects

If the Sohre approach is taken in a philosophical light, it clearly indicates the need for a robust design. This is true for the basic equipment as well as the installation of foundations and piping. All of the factors were considered in the approach Sohre presented, even if in some cases, they may have been considered subjective. The key to the robust approach can be simplified as low deflection. On a rotor, the shorter the bearing span and/or the heavier the shaft cross section, the lower the deflection. This tends to increase the reliability aspect. On a foundation, heavier sections tend to have lower deflection, which contributes to the ability to maintain train alignment. Better alignment is one of the factors that contributes to higher reliability. 

The process application can have a significant impact on the reliability of a compressor. The reliability aspects take on two paths the nature of the gas being compressed and the correct compressor selection for the service. 

Performance-influencing factors analysis is an important part of the human reliability aspects of risk assessment. It can be applied in two areas. The first of these is the qualitative prediction of possible errors that could have a major impact on plant or personnel safety. The second is the evaluation of the operational conditions under which tasks are performed. These conditions will have a major impact in determining the probability that a particular error will be committed, and hence need to be systematically assessed as part of the quantification process. This application of PIFs will be described in Chapters 4 and 5. 

Despite the advances made with the Rev 2 formulation, reliability aspects, such as orifice plate cleanliness, and kogation, are still poor. To address the orifice plate cleanliness issue, we add 0.1 % of Zonyl FSA (an anionic fluorosurfactant from DuPont), following what has been done in the patent hterature. Furthermore, we add the combination of 0.3% Phospholan 9NP (a nonylphenol ethoxylate phosphate ester, from Akzo Nobel corporation), and 0.05% EDTA (ethylenediaminetetraacetic acid), to prevent resistor deposits, as discussed in the patent literature. With such modifications, the Rev 3 ink gives improved orifice plate cleanliness and kogation. The surface tension is lower for this formulation. Though this can lead to bleed problems on paper, here we have specified that the color inks will be at low pH, hence wiU react with the black pigment, and thus combating bleed problems. Furthermore excessive tail/aerosol formation may become a problem with the decreased surface tension, as mentioned back in Section 1.2 — this performance must be checked. 

In modem cars, microsensors play an essential and increasingly important role as the interface between the vehicle, with its complex functions of motor management, chassis systems, safety, as well as comfort and convenience on the one hand, and the respective electronic control units on the other hand. Microsensors need to function in a harsh environment over the entire lifetime of an automobile. Therefore reliability aspects have come more and more into the focus of engineering and research activities in microsystem technology. 

This section describes a methodical procedure that allows reliability issues to be approached efficiently. MEMS reveal specific reliability aspects, which differ considerably from the reliability issues of integrated circuits and macroscopic devices. A classification of typical MEMS-failure modes is given, as well as an overview of lifetime distribution models. The extraction of reliability parameters is a Tack of failures situation using accelerated aging and suitable models. In a case study, the implementation of the methodology is illustrated with a real-fife example of dynamic mechanical stress on a thin membrane in a hot-film mass-airflow sensor. 

Consideration of reliability aspects in all phases of product development... 

An essential goal is therefore to consider reliability aspects from the very beginning of a development project and to include it already in the concept and design phases ( design for reliability ). This holistic approach to increasing sensor lifetime is based on the idea of considering reliability aspects in all phases of product development (Fig. 5.9.1). 

The reliability aspects of MEMS also reveal some basic differences in comparison to lifetime considerations for macroscopic devices. The ratio of surface to volume increases linearly with additional miniaturization, resulting in forces that eventually are no longer dominated by mass but by surface effects. Friction and sticking are therefore typical problems of microstructures, which have to be considered in the design. 

An overview of the reliability aspects of microsystems is given in Figure 5.9.3. 

Using horizontal directions and vertical angles from at least two stations, the 3-D coordinates of the object points can be determined by intersection. For reliability aspects, more than two beams are required. This concept was considered during the design of the wall systems (see Sect.4.1). 

Han KH, Frazier AB (2005) Reliability aspects of packaging and integration technology for microfluidic systems. IEEE Trans Device Mater Reliab 5(3) 452- 57... 

The AAC source is not normally directly connected to the plant s main or standby offsite power sources or to the Class IE power distribution system, thus minimizing the potential for common cause failure. Quality assurance guidelines for the AAC are given in CESSAR-DC Section 8.3.1.1.5.5. (The emergency diesel generator reliability aspect of Station Blackout as described in Regulatory Guide 1.155 is covered in USI B-56.)... 

A. Christou, Reliability Aspects of Moisture and Ionic Contamination Diffusion Through Hybrid Encapsulants, in Proceedings of the Technical Program—International Microelectronics Conference (1978) p. 237, Industrial Scientific Conference Management, Inc., New York. Electric insulators and dielectrics Silicone/epoxy-polyurethane interpenetrating networks, moisture, and ion diffusion through potting compounds. 

Furthermore, the capability of the profession at this time is limited on the evaluation of uncertainties involved with the available methods of movement or deformation analysis. As a result, reliability aspect of LRFD design cannot be implemented at this time. Thus, once the design load is available, the remainder of the LRFD service limit state design, including the types and components of deformations, and techniques and methods of analysis and design is similar to the serviceability aspects of WSD or ASD. 

There may be a nnmber of individuals who could be classified as users, e.g. operators, maintenance personnel, managers etc. and the user documentation needs to be relevant and intelUgible to them all. There is a tendency among non-specialists to view computers as black boxes . This view is not conducive to making optimum use of the system facilities and is unlikely to be alleviated by an incomprehensible user manual. Any process which will deepen understanding of the system will improve safely by improving the human reliability aspect. 

We estimate the reliability aspects of our implementation by considering the time that the system operates on the highest service level. We compare that time and the... 

However, in this context, reliability aspects are more important ... 

Flammini, F., Marrone, S., Mazzocca, N. Vittorini, V. 2006 Modelling structural reliability aspects of ERTMS/ETCS by Fault Trees and Bayesian Networks. Proc. of the European Safety Reliability Conference, ESREL, 2006. 

The organization of the paper is as follows. We start with short analysis of related works, next virtualization and its reliability aspects are presented. In the section 4 the availability of a web application is defined including reliability and functional aspects. It is followed by a detail model of assessing the web application availability by computer simulation. Finally, a test case system is presented and its availability calculated as it varies in time (over a week). We conclude with a short summary. 

In Chapter 3, we consider the reliability aspects of DTS and their impact on the required level of redundancy. The reliability analysis lets us determine the level of redundancy that ensures continuity of service at an economically justified level of assurance. There are a lot of techniques that support this type of analysis (Avizienis et al. 2000, Jarnicki et al. 2008, Walkowiak Mazurkiewicz 2010, Zio 2007). 

Figu re 1. Fatigue levels of solder joints rating systems. This rating system was presented by Philips in a lead-free reliability aspects study. 

Reliability Aspects of Lead-Free Solders in Electronic Assemblies... 

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