Availability estimation and management for complex processing systems

“Availability” is the terminology used in asset intensive industries such as petrochemical and hydrocarbons processing to describe the readiness of equipment, systems or plants to perform their designed functions. It is a measure to suggest a facility’s capability of meeting targeted production in a safe working environment. Availability is also vital as it encompasses reliability and maintainability, allowing engineers to manage and operate facilities by focusing on one performance indicator. These benefits make availability a very demanding and highly desired area of interest and research for both industry and academia. In this dissertation, new models, approaches and algorithms have been explored to estimate and manage the availability of complex hydrocarbon processing systems. The risk of equipment failure and its effect on availability is vital in the hydrocarbon industry, and is also explored in this research. The importance of availability encouraged companies to invest in this domain by putting efforts and resources to develop novel techniques for system availability enhancement. Most of the work in this area is focused on individual equipment compared to facility or system level availability assessment and management. This research is focused on developing an new systematic methods to estimate system availability. The main focus areas in this research are to address availability estimation and management through physical asset management, risk-based availability estimation strategies, availability and safety using a failure assessment framework, and availability enhancement using early equipment fault detection and maintenance scheduling optimization.

INVERTEBRATE CONTRIBUTION TO LEAF BREAKDOWN IN PYNN’S BROOK, NL.

Leaf bags of fine and coarse mesh were placed at two locations, one with an open tree canopy, the other with a closed tree canopy, in Pynn’s Brook on June 30th 2015. Bags were collected after 2, 30, 37 and 44 days. After collection, invertebrates were counted and leaf material remaining was determined to measure leaf breakdown rate. There was no significant difference in leaf mass remaining (R) between the two sites. Comparisons between mesh types found a difference in leaf breakdown at two collection days. The difference at 2 days was small (2.7%) and may not be biologically meaningful. At 37 days, the difference was larger (8.41%) and may be related to a larger proportion of shredder taxa, seen in coarse mesh bags, or higher absolute numbers of invertebrates. The invertebrate community was dominated by Diptera spp. across all collection days and mesh types, but after 37 days, communities in coarse mesh bags had a higher proportion of shredder orders than did fine mesh bags.