A system-theoretic, control-inspired view and approach to process safety

Accidents in the process industry continue to occur, and we do not seem to be making much progress in reducing them (Venkatasubramanian, 2011). Postmortem analysis has indicated that they were preventable and had similar systemic causes (Kletz, 2003). Why do we fail to learn from the past and make adequate changes to prevent their reappearance? A variety of explanations have been offered; operators' faults, component failures, lax supervision of operations, poor maintenance, etc. All of these explanations, and many others, have been exhaustively studied, analyzed, “systematized” into causal groups, and a variety of approaches have been developed to address them. Even so, they still occur with significant numbers of fatalities and injured people, with significant disruption of productive operations and frequently extensive destruction of the surrounding environment, both physical and social

Genotype's influence on tissue characteristics and mortality rate during thermal stress

Caribbean Acropora cervicornis, commonly named staghorn coral, is a stony coral and reef building organism that is threatened by climate change because it can only withstand a small temperature and pH range before experiencing stress[1]. To aide this population, conservation efforts aim to identify corals with higher chances of survival against thermal stress via the proxy of mortality rate at a given temperature. However, these studies can span months, resulting in slow progress. If there is a faster procedure to estimate thermal tolerance, coral nursery and reef restoration programs would be able to denote the successful genotypes quickly and easily, therefore enabling higher efficacy outplanting programs. A key process to consider is the stress response. Stress response necessitates energy for the reparation of damages from the production of reactive oxygen species. Therefore, successful energy acquisition from heterotrophic feeding and the symbiotic relationship with photosynthetic zooxanthellae may impact a coral’s heat tolerance. This study focuses on determining if thermal tolerance is linked to any tissue properties that are linked to energy storage and production, including lipid content, zooxanthellae count, chlorophyll density, carbohydrates, and proteins. We hypothesize that larger densities of energy-enriching qualities will correlate with higher survivorship. Overall, the four tissue properties did not show significant influence on the thermal tolerance of staghorn corals. The data demonstrates that energy availability due to these tissue properties do not correlate with the survival of the coral during heat anomalies. However, we know that there is a quality that exists that distinguishes the LT50 values from each other. Once this quality is found, it may still be possible to find a quick measurement of corals to differentiate individuals that will have higher success on the reef against thermal challenges, making them better candidates for reef restoration projects

Operability studies in heat exchanger networks : analysis, control and synthesis

Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1988.Includes bibliographical references.by John Christos Calandranis.Sc.D