Critical event

TRACES (1968) Technology in Retrospect and Critical Events in Science (TRACES). Illinois Institute of Technology, Research Institute published for the National Science Foundation (no editor or author named). 

WAMCOM Fault tree with susceptibilities 1 Uses modularizatton and SETS to more effectively identify cutsets that contain critical events, critical nindcmt events, and significant common cause events or to describe common cause sets for each failure Can identify etymon total or partial links between fault-tree components con handle very large fault trees CDC 7600, Available froni i I l Rl i V 1.-Cenler... 

This technique sets out to collect data about near-incidents or critical events that have been experienced by the operating team but that are unlikely to be documented. The basic premise of the technique is that events that could have led to serious consequences would tend to be remembered by the workers. Through individual or group interviews, significant events are recalled which are then analyzed in order to generate useful information about the difficulties involved in the performance of a task, the adequacy of the operating procedures, any problems with the equipment or control panel design and so on. The technique can be used in three areas ... 

When the diagram is complete, the analyst proceeds through it to identify sets of events that were critical in the accident sequence. These critical events are then subjected to a further causal analysis using other techniques such as root cause coding, described below in Section 6.8.4. 

The first case study describes the application of the sequentially timed event plotting (STEP) technique to the incident investigation of a hydrocarbon leak accident. Following the analysis of the event sequence using STEP, the critical event causes are then analyzed using the root cause tree. 

This case study concerns the events leading up to the hydrocarbon explosion which was the starting point for the Piper Alpha offshore disaster. It describes the investigation of the incident using the sequentially timed events plotting (STEP) technique. Based on the STEP work sheet developed, the critical events involved in the incident are identified and analyzed in order to identify their root causes. 

This stage involved the identification of critical actions and events in the incident process. Three critical events were identified from the STEP diagram. These were... 

The problem manifested itself as an equipment problem, namely a leaking flange joint. The department broadly responsible for this area (but not for implementing, monitoring, and subsequent recommendations) is the engineering department, as the specialist contractors work for them. The critical event took place during a corrective maintenance operation. From here, two separate root causes were identified, based on the data from the investigation. 

CRITICAL EVENT 2 Changeover between Day and Night Supervisor ... 

CRITICAL EVENT 3 Contractor Fails to Report Status of Work ... 

The root causes for this critical event both concern the operations department and the service department who ran the contractor maintenance team. The operations department (i.e., the day shift operations supervisor) failed to provide adequate supervision and instructions to the contractor team. Explanations of the nature of the permit-to-work systems (i.e., the need to report back at end of shift) should have been given, and the possibility and implications of work not being completed before the end of the shift should have been considered by both parties. 

The case study has documented the investigation and root cause analysis process applied to the hydrocarbon explosion that initiated the Piper Alpha incident. The case study serves to illustrate the use of the STEP technique, which provides a clear graphical representation of the agents and events involved in the incident process. The case study also demonstrates the identification of the critical events in the sequence which significantly influenced the outcome of the incident. Finally the root causes of these critical events were determined. This allows the analyst to evaluate why they occurred and indicated areas to be addressed in developing effechve error reduchon strategies. 

Metal polishing mechanisms appear to be considerably different from silica polishing. The critical event that determines the polishing process in metal CMP appears not only to be influenced by the crystallographic/microstructure deformation process but also to relate to more complex components of slurry [18]. To better understand the removal mechanism in metal CMP, tungsten is chosen, since both industrial and laboratory CMP data are available for this metal, and its abrasion behavior as a metal is similar to that of other ductile metals which have been studied quite extensively under two- and three-body abrasion [66]. 

Knudsen TB, O Hara MF, Charlap JH, Donahue RJ, Craig RC. 2000. Mitochondrial mechanisms of developmental toxicity critical events and intervention. Toxicologist 54 69-70. 

Inspections should be carried out as study-specific inspections for critical phases of the study or as a batch of process inspections relating to critical tasks which are performed regularly and although may not be inspected for a specific study are inspected on a regular basis (e.g., once per month). The coordination of inspections is perhaps more difficult to predict than actually conducting the critical event. The use of local QA staff close to the sites where the field work is being conducted helps to reduce the travel time to the field sites and also the down time if the critical event cannot be made at the specified time. The use of computer planning tools to schedule fieldwork is very helpful, not only to the field staff but also to QA. 

If properly designed, the soil-water reservoir of an ET cover will be only partially filled most of the time. The greatest amount of water that must be stored in the soil will be defined by major or critical events. The critical event may result from a single storm event or a series of storms. The model used for design or evaluation of an ET landfill cover should be capable of evaluating the cumulative effect of each day s water balance activity and thus identify critical events. 

The reaction of metabolically generated polycyclic aromatic diol epoxides with DNA Ua vivo is believed to be an important and critical event in chemical carcinogenesis Cl,2). In recent years, much attention has been devoted to studies of diol epoxide-nucleic acid interactions in aqueous model systems. The most widely studied reactive intermediate is benzo(a)pyrene-7,8-diol-9,10-epoxide (BaPDE), which is the ultimate biologically active metabolite of the well known and ubiquitous environmental pollutant benzo(a)pyrene. There are four different stereoisomers of BaPDE (Figure 1) which are characterized by differences in biological activities, and reactivities with DNA (2-4). In this review, emphasis is placed on studies of reaction mechanisms of BPDE and related compounds with DNA, and the structures of the adducts formed. 

The FGFs stimulate the proliferation of mesodermally and ectodermally-derived cells and play central roles in mammalian development. Members of the FGF family are expressed in the embryonic period and are required for several critical events in neural development and specifically for neural induction. FGF-8 is necessary for positional identity required for axial specification and patterning of limb development. FGF-2 stimulates the proliferation of multipotential stem cells that subsequently give rise to neurons of the cortex and other brain regions. 

Some xenobiotics may have divergent mechanisms of autoimmune responses. For example, hydralazine demonstrates adduct reactivity as well as inhibition of DNA methylation [68,73], while procainamide inhibits DNA methylation, forms immunogenic NPA, and disrupts clonal selection in the thymus [68, 72, 74], It is this complicated pattern of effects that makes assessment of autoimmune potential in the laboratory for new xenobiotics almost impossible. Animal models can sometimes be recreated to resemble human disease [74], and thus may be useful for therapy considerations, but are difficult to utilize for screening chemicals for hazard potential due to the diverse nature of autoimmunity mechanisms and physiological presentation. While evidence supports many different mechanisms for xenobiotic-induced autoimmune reactions, none have conclusively demonstrated the critical events necessary to lead to the development of autoimmune disease. Therefore, it is difficult to predict or identify xenobiotics that might possess the potential to elicit autoimmune disorders. 

From hindsight analyses of accidents by Heinrich (Heinrich, 1959), Turner (Turner, 1978), Leplat (Leplat, 1987), Reason (Reason, 1997), etc., it is known that failures or deviations in normal operations are present prior to, and are directly related with, an accident. From hindsight analysis as reported in FACTS, the failures or deviations as well as the accident trajectory or causal path, of 70 accidents are known. To derive the risk coverage area these deviations, are placed in the risk matrix. The only deviations taken into account are those which occur in the operational process and are part of the accident trajectory or causal path prior to the critical events as described in FACTS. So the latent conditions lying behind these operational deviations as described by Reason (Reason, 1997) are not yet taken into account but will be discussed in the following Chapter. 

Using these definitions of deviations, hard and soft deviations were found in the causal path prior to the critical events of the 70 accidents. In total 158 deviations were derived from the operational process. These deviations consist of 48% hard and 52% soft deviations. 

Critical currents, 23 821-823 in superconducting, 23 819-825 Critical event (CE), 15 462 Critical failure, 26 982 Critical features, in separating nonideal liquid mixtures, 22 307 Critical fields, thermodynamic, 23 809-811 Critical flocculation concentration, 11 631 Critical item evaluation, for reliability, 26 991... 

Lysosomal enzymes are glycosylated and modified in a characteristic way. Most importantly, when they arrive in the Golgi apparatus, specific mannose residues in their oligosaccharide chains are phosphorylated. This phosphorylation is the critical event that removes them Corn the secretion pathway and directs them to lysosomes. Genetic defects affecting this phosphorylation produce I-ceU disease in which lysosomal enzymes are released into the ejctracellular space, and inclusion bodies accumulate in the cell, compromising its function. 

A component for identifying the critical events and conditions (causal factors) in the incident sequence. 

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