Managing fire risk onboard offshore platforms: Lessons from Piper Alpha and probabilistic assessment of risk reduction measures

The offshore oil platform Piper Alpha was destroyed in July 1988 by a catastrophic fire. The causes of the accident included a combination of technical and organizational factors. In this paper, I describe the accident, its chronology, and the dependencies involved. I then examine some of the human errors that led to the disaster and their organizational roots, such as economic pressures, the permit-to-work system, and the inadequacy of regulatory oversight in the United Kingdom at the time of the accident. Risk-reduction measures can be costly, however, and priorities must be set based on costs and benefits. To this end, I describe a probabilistic risk analysis model that can be used to assess the benefits of different fire safety measures, focusing on reinforcing the emergency water pumps.     

Effect of transglutaminase on the quality of wheat-based pasta products

Transglutaminase (TG) enzyme was tested in T. aestivum and T. durum wheat-based model systems to evaluate the quality improvement to pasta imparted by cross-linking. Quality was measured by the enhancement in sensory and cooking properties. In this process, tests were also performed to establish the biochemical structure-functions of the proteins involved at TG enzyme concentrations between 10 and 200 mg kg⁻¹. It was observed that the amounts of water/salt-, the alcohol- and the alkali-soluble protein fractions were reduced significantly. Change in the molecular weight distribution assessed by SDS PAGE was also noticed. The sensory properties were observed to improve from high water uptake and low cooking loss. The TG treatment changed the gluten structure in the modified pasta products. Immune-reactive gliadin fractions were detected by immunoblotting and independently measured by competitive indirect ELISA, using the anti-gliadin rabbit IgG.     

The far infra-red spectrum of crystalline polytetrafluoroethylene

The far infra-red spectrum of highly crystalline polytetrafluoroethylene has been shown to contain a new band near 33cm^?1, the band at 55cm^?1 has been shown to be a close doublet and two further bands at 291 and 308cm^?1 have been observed. These results strongly support the conclusions of Boerio and Koenig from Raman observations that the unit cell contains at least two molecular segments.     

Characterization of different bondings in some divalent metal niobates of columbite structure

The structural characteristics of the columbite niobates MNb₂O₆ (M = Mg, Ca, Mn, Fe, Co, Ni, Cu, Zn, Cd) from their X ray diffraction powder patterns and indexed according to the Pbcn space group are given. Cell parameters are refined for each compound. Previous spectroscopic studies by normal coordinate analysis provide the basis for a discussion of the precise nature of the NbO and MO bonds. Force constants and bond order are given and the influence of the electronegativity of the M²⁺ cations upon these bonds is shown.     

Peroxid-induzierte thioladdition an polybutadien

The free-radical addition of 1-octanediol or 3-(trimethoxysilyl)-1-propanethiol on polybutadiene occurs redox-induced with dibenzoylperoxid (DBPO) at room temperature, without any side-reaction. 1,4-trans double bonds do not undergo thiol reactions, similar to the photochemical addition. The molecular weight distribution of the products is comparable with that of the initial polybutadiene.     

Bohr-Hobelversuch zur Bestimmung des Einflusses von Bindemittelzusätzen auf die Wirkungstiefe von lösemittelhaltigen Präparaten

Ohne Zusammenfassung Erweiterte Fassung eines Vortrags des 1. Verfassers auf der 14. Internationalen Holzschutztagung der Deutschen Gesellschaft für Holzforschung. Mainz. 7. Oktober 1976.     

The use of various buffers in the preparation of human lymphocytes for SEM observation

A study is presented of various buffers utilized in the preparation of human lymphocytes for scanning electron microscopy. Of nineteen different buffers tested, Hanks' balanced salt solution +0·04 mol sucrose appeared most adequate for satisfactory preservation of lymphocyte surface architecture.     

Comparison of the relative quantities of aroma compounds found in fresh apricot (Prunus armeniaca) from six different varieties

Summary The volatile components of fresh apricot (Prunus armeniaca) were isolated by vacuum distillation and fractionated on a silica gel column. Analysis by gaschromatography coupled with mass spectrometry led to the identification of 82 compounds, 60 of which were found for the first time in this fruit. Six varieties, cultivated in the south of France were compared for their firmness, acidity, sweetness and for their content of 56 volatile components. Precoce de Tyrinthe was the least aromatic variety, but produced fruits very early in the season. Palsteyn gave acidic but rather aromatic fruits. Moniqui possessed large but perishable fruits with flowery aroma due to the presence of terpenic ketones. Rouge du Roussillon contained all the identified volatile compounds and possessed a pleasant aroma. Polonais contained many C₆-compounds with herbaceous notes and Bergeron was rich in lactones but poor in terpenic alcohols.

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Über die Gehalte an Aromakomponenten von sechs Aprikosensorten (Prunus armeniaca)

Zusammenfassung Die flüchtigen Aromastoffe von Aprikosen (Prunus armeniaca) wurden durch Vakuumdestillation und anschließende chromatographische Vortrennung und Kieselgel isoliert. Mit kombinierter gaschromatographischer Analyse wurden 82 Komponenten, davon 60 zum ersten Mal, identifiziert. Die Gehalte an Zucker, Säuren und 56 Aromakomponenten von 6 französischen Aprikosensorten wurden miteinander verglichen. Die Sorte Precoce de Tyrinthe ist wenig aromatisch aber frühreif, die Sorte Moniqui trägt große Früchte mit einem Blumenaroma von Ketonen, während Rouge du Roussillon viele Komponenten und das angenehmste Aroma besitzt. Die Sorte Polonais zeichnet sich durch den höchsten Gehalt an C₆-Komponenten und ein krautartiges Aroma aus. Die Sorte Bergeron ist reich an Lactonen, jedoch arm an Terpenalkoholen.

     

Probabilistic risk analysis and risk-based priority scale for the tiles of the space shuttle

The thermal protection system of the space shuttle is one of its most critical subsystems because it protects the orbiter from heavy heat loads at reentry into the atmosphere. To optimize NASA's allocation of risk management resources, a probabilistic risk analysis model is developed for the black tiles, and a risk-criticality index is computed for each tile based on its contribution to the overall probability of loss of vehicle and crew (LOV/C). This assessment is based on the susceptibility of the tiles (i.e. their probabilities of debonding), and on the vulnerability of the orbiter to specific tile losses given the criticality of the subsystems under the aluminum skin in various locations. The two main initiating events are linked to the debonding of a tile, caused either by debris hits or by a weak bond because of poor tile installation. The PRA model relies on a partition of the orbiter's surface according to four parameters: the probability of debris hits, the probability of secondary tile loss once a first tile has debonded, the probability of burnthrough given a failure patch of specified size, and the probability of LOV given a hole in the orbiter's aluminum skin. The results show that the contribution of the tiles to the overall probability of LOV is about 10%. They also include a map of the orbiter's surface showing the relative risk-criticality of tiles at various locations. It was found that 85% of the risk can be attributed to 15% of the tiles, thus allowing the management to allocate more effort and resources to the maintenance of the most risk-critical tiles.