A review of the science and art of visual examination in failure analysis

Visual examination is usually the first step in a failure analysis, but it is not a subject about which much has been written. In this paper, techniques of visual examination and documentation using digital photography are discussed. The use of different types of lighting to reveal characteristics of manufactured and fracture surfaces is explored. Practical examples of lighting setups and photographs obtained using these setups are presented.     

Control chart design a review of standard practice

Many standard texts on SPC offer simple procedures for setting up control charts. Although the procedures work well in some situations, there are many instances where the procedures do not produce useful charts. The failure to sustain SPC initiatives is often due to an over simplistic model of process variability. This paper examines the widely used procedures for setting up control charts and illustrates how these may fail when the process variability has certain characteristics. A more robust alternative procedure is examined in some detail. This involves taking a closer look at process variability and incorporating this with control chart design.     

The dynamic histogram chart

This paper discusses a dynamic histogram control chart which combines some ideas of histograms, X charts, zone charts and chi-square charts. The chart is easy to use, easy to understand, and has quick response times. Another feature is that it does not require normal data as X charts and zone charts do. The chart is especially useful for controlling processes with low data accumulation rates such as chemical processes or for controlling processes involving short runs such as job shops.     

Reflections on and a short review of the science of team science

Scientometrics - We provide a short overview of the science of team science (SciTS). Starting from the notion of a scientific team, we move to interdisciplinary studies and finally the Science of...     

The effect of continuously updating control chart limits on control chart performance

An open topic within statistical process monitoring is the effect on control chart properties of updating the control chart limits during the monitoring period. The challenge is to use the correct data for updating the control limits as in‐control data could be incorrectly classified as out of control and therefore not used for re‐estimating the parameters, and out‐of‐control data could be classified as in control and therefore used for re‐estimating. In the present article, we study the effect of updating the Shewhart, cumulative sum, and exponentially weighted moving average control chart limits. We simulate different scenarios: the monitoring data could be in or out of control, and the practitioner may or may not be able to find out whether the process is indeed out of control when the control chart gives a signal. The results reveal that the variation in the performance of the conditional control charts decreases significantly as a result of updating the control chart limits when the updating data are in control and also when the updating data are out of control and the practitioner is able to classify correctly data samples that produce a signal. However, when a practitioner is not able to classify a signal correctly, the advisability of updating depends on the type of control chart and the level of data contamination.     

The double sampling range chart

The R chart and the S² chart are the usual charts for monitoring process dispersion; however, the double sampling (DS) scheme has only be used with the S² chart. The difficulty in obtaining the properties of the DS R chart might explain the lack of papers dealing with this type of DS chart. The S² chart has the advantage of being more efficient than the R chart, but the same is not always observed with their DS versions. Depending on the size of the 2 samples, the DS R chart performs better. The trade‐off between operational simplicity and power of detection might lead the practitioner to choose the DS R chart, even with the DS S² chart signaling faster.     

Motorcycle helmets—A state of the art review

This paper tries to make an overview of the work carried out by scientific community in the area of road helmets safety. In an area that is constantly being pushed forward by market competition, self-awareness of danger and tighter standards, several research groups around the world have contributed to safety gear improvement.     

The perovskite structure – a review of its role in ceramic science and technology

Starting with the history of the fundamental science of the relation of structure to composition delineated completely by Goldschmidt, we use the perovskite structure to illustrate the enormous power of crystal chemistry-based intelligent synthesis in creating new materials. The perovskite structure is shown to be the single most versatile ceramic host. By appropriate changes in composition one can modify the most significant electroceramic dielectric (BaTiO₃ and its relatives) phase in industry, into metallic conductors, superconductors or the highest pressure phases in the earth. After an historical introduction of the science, detailed treatment of the applications is confined to the most recent research on novel uses in piezoelectric, ferroelectric and related applications. Received: 29 November 1999 / Accepted: 3 July 2000     

The second art

Abstract

The figure of the accomplished artist in one medium who develops an expertise in another always attracts interest, whether in a sense of amazement over so much energy, or in a sense of relief that even a virtuoso can be an amateur. One thinks ofEinstein and his violin, Gottfried Keller and his painting, William Thackeray and his caricatures, and many others. Emile Zola, Photograph presents us with a handsomely produced addition to this list, but the main role of this book is, of course, to fill another niche in the Zola shrine. Relatively little technical information is giveu, and one suspects that the primary audience was intended to be Zola admirers, lay as well as professional. Although there are several biographical sketches, the reader not familiar with Zola's life will not be able to appreciate the book fully, particularly since Zola's passion for photography developed only near the end of his life.     

A control scheme integrating the T chart and TCUSUM chart

This article proposes an integrated scheme (T&TCUSUM chart) which combines a Shewhart T chart and a TCUSUM chart (a CUSUM‐type T chart) to monitor the time interval T between the occurrences of an event or the time between events. The performance studies show that the T&TCUSUM chart can effectively improve the overall performance over the entire T shift range. On average, it is more effective than the T chart by 26.66% and the TCUSUM chart by 14.12%. Moreover, the T&TCUSUM chart performs more consistently than other charts for the detection of either small or large T shifts, because it has the strength of both the T chart (more sensitive to large shifts) and the TCUSUM chart (more sensitive to small shifts). The implementation of the new chart is almost as easy as the operation of a TCUSUM chart. Copyright © 2010 John Wiley & Sons, Ltd.     

The measurement of broadband ultrasonic attenuation in cancellous bone--a review of the science and technology

The measurement of broadband ultrasonic attenuation (BUA) in cancellous bone at the calcaneus was first described in 1984. The assessment of osteoporosis by BUA has recently been recognized by Universities UK, within its EurekaUK book, as being one of the "100 discoveries and developments in UK Universities that have changed the world" over the past 50 years, covering the whole academic spectrum from the arts and humanities to science and technology. Indeed, BUA technique has been clinically validated and is utilized worldwide, with at least seven commercial systems providing calcaneal BUA measurement. However, a fundamental understanding of the dependence of BUA upon the material and structural properties of cancellous bone is still lacking. This review aims to provide a science- and technology-orientated perspective on the application of BUA to the medical disease of osteoporosis.     

The classification of science and the science of classification

With a view toward a system of science indicators which is flexible, appropriate, and unambiguous, a brief discussion is given of the theory of classification. This is then applied to three situations arising in input indicators for science, and it is shown how the presently used formalism for such indicators could be improved and thus eliminate unnecessary disputes in the practical application of such indicators.     

Designing for creativity: A state of the art review

This review concerns itself with the so-called structured aids to creative behaviour. The published literature is outlined and shown to be extensive but fragmentary, diffuse and inconclusive. Four major families of techniques are discussed: brainstorming, synectics, morphological analysis and lateral thinking. Some less well known techniques are also considered briefly, and the problem of classification considered. There is little evidence of an accepted body of knowledge or paradigm, and the field contains contradictory results. It is argued that more attention needs to be directed towards understanding relationships between what the techniques are supposed to be doing on a theoretical level, and what they seem to be achieving in practice. Some fruitful areas for research and for practical actions are suggested, and an attempt has been made to summarize current views of practitioners that have not yet found widespread diffusion.     

The SPRT control chart for process dispersion

This paper investigates the statistical performance of a sequential probability ratio test control chart for monitoring the dispersion of a normally distributed process. The expressions for statistical performance measures of the chart are derived using a Markov chain approach. It is shown through numerical comparisons that the overall statistical performance of this chart is superior to that of the existing competitor charts for dispersion. An example illustrating an application of the chart in practice is provided.     

The economic performance of the Shewhart t chart

In the production of small batches of customized parts, high flexibility and frequent switching of production from one product variant to another could not allow for the implementation of a control chart to monitor the process. In fact, when a short‐run production should be started, the distribution parameters of the quality characteristics to be monitored are frequentlytextitunknown and the production run is too short to get sufficient Phase I samples. To overcome this problem, the statistical properties of Shewhart t charts monitoring a short production run have been recently discussed in literature. In this paper, we investigate their economic performance: the SPC inspection cost optimization is constrained by the manufacturing and the inspection activities configuration. The decision variables of the problem include the chart design parameters and the size of batches of parts to be worked and released to the local inspection area. A numerical analysis aimed at evaluating the economic performance of the Shewhart t chart vs the Shewhart chart with known parameters has been performed. The expected economic loss associated with the implementation of the Shewhart t chart is acceptable with respect to the ‘ideal’ condition of the control chart with known parameters when the cost optimization is achieved without a statistical constraint limiting the number of expected false alarms. Finally, the effect of an erroneous initial set‐up on the correctness of the inspection cost estimation has been investigated. Copyright © 2011 John Wiley & Sons, Ltd.