Expert systems for fault tree synthesis

Hazard and operability (HAZOP) studies on chemical process plants are very time consuming, and often tedious, tasks. The requirement for HAZOP studies is that a team of experts systematically analyse every conceivable process deviation, identifying possible causes and any hazards that may result. The systematic nature of the task, and the fact that some team members may be unoccupied for much of the time, can lead to tedium, which in turn may lead to serious errors or omissions. An aid to HAZOP are fault trees, which present the system failure logic graphically such that the study team can readily assimilate their findings. Fault trees are also useful to the identification of design weaknesses, and may additionally be used to estimate the likelihood of hazardous events occurring. The one drawback of fault trees is that they are difficult to generate by hand. This is because of the sheer size and complexity of modern process plants. The work in this thesis proposed a computer-based method to aid the development of fault trees for chemical process plants. The aim is to produce concise, structured fault trees that are easy for analysts to understand. Standard plant input-output equation models for major process units are modified such that they include ancillary units and pipework. This results in a reduction in the nodes required to represent a plant. Control loops and protective systems are modelled as operators which act on process variables. This modelling maintains the functionality of loops, making fault tree generation easier and improving the structure of the fault trees produced. A method, called event ordering, is proposed which allows the magnitude of deviations of controlled or measured variables to be defined in terms of the control loops and protective systems with which they are associated

Environmental factors in design and operation of wastewater sludge drying beds

Students supported: 1 Student AssistantThe dewatering characteristics of anaerobically digested primary and activated sludge were investigated under eight selected combinations of laboratory controlled air temperature and relative humidity using three open, drained model beds, as well as a closed, drained and an open, nondrained bed. The evaporation rate from a free water surface was also determined. Moisture content, drainage, evaporative weight loss, and sludge surface recession were measured and recorded periodically throughout the two week period of each of the eight experiments. Relationships were shown to exist between sludge moisture content, evaporation rate from a free water surface, and the parameters (delta)T (the difference between dry and wet bulb temperature) and (delta)H (the difference between saturation and absolute humidity). It was found that moisture gradients developed within the dewatering sludge which generally increased with time and (delta)T. An inverse relationship was noted between drainage and evaporation which was influenced by dry bulb temperature because of its effect upon water viscosity.Project # A-042-MO Agreement # 14-31-0001-322

Fast and Furious: The Influence of Implicit Aggression, Premeditation, and Provoking Situations on Malevolent Creativity

Being intentionally harmful in original ways has been termed \u27malevolent creativity.\u27 The empirical study of malevolent creativity is still in its infancy, so developing a strong foundation of its antecedents is paramount. Three factors were identified as potentially influencing the generation of malevolently creative ideas: implicit aggression, which is aggression that is beyond one’s conscious awareness; premeditation, a facet of impulsivity that pertains to the degree of planning and forethought an individual engages in before acting; and situations that condone or otherwise provoke the use of malevolent creativity. Consistent with our hypotheses, and in accordance with the theory of trait activation, a 3-way interaction among those factors was obtained. Specifically, the interaction indicates that individuals who are more implicitly aggressive and less premeditative are more likely to be malevolently creative in response to situations that provoke malevolent creativity

Newer treatments for fibromyalgia syndrome

Fibromyalgia syndrome is a common chronic pain disorder of unknown etiology. The lack of understanding of the pathophysiology of fibromyalgia has made this condition frustrating for patients and clinicians alike. The most common symptoms of this disorder are chronic widespread pain, fatigue, sleep disturbances, difficulty with memory, and morning stiffness. Emerging evidence points towards augmented pain processing within the central nervous system (CNS) as having a primary role in the pathophysiology of this disorder. Currently the two drugs that are approved by the United States Food and Drug Administration (FDA) for the management of fibromyalgia are pregabalin and duloxetine. Newer data suggests that milnacipran, a dual norepinephrine and serotonin reuptake inhibitor, may be promising for the treatment of fibromyalgia. A double-blind, placebo-controlled trial of milnacipran in 125 fibromyalgia patients showed significant improvements relative to placebo. Milnacipran given either once or twice daily at doses up to 200 mg/day was generally well tolerated and yielded significant improvements relative to placebo on measures of pain, patient’s global impression of change in their disease state, physical function, and fatigue. Future studies are needed to validate the efficacy of milnacipran in fibromyalgia

Effect of a Fruit and Vegetable Prescription Program on Children's Fruit and Vegetable Consumption.

IntroductionMost children in families with low income do not meet dietary guidance on fruit and vegetable consumption. Fruit and vegetable prescription programs improve access to and affordability of health-supporting foods for adults, but their effect on dietary behavior among children is not known. The objective of this study was to describe the extent to which exposure to a fruit and vegetable prescription program was associated with changes in consumption among participants aged 2 to 18.MethodsWe used data from a modified National Cancer Institute screener to calculate fruit and vegetable intake among 883 children who were overweight or had obesity and participated in a 4- to 6-month fruit and vegetable prescription program at federally qualified health centers during 4 years (2012-2015). Secondary analyses in 2017 included paired t tests to compare change in fruit and vegetable consumption (cups/day) between first and last visits and multivariable linear regressions, including propensity dose-adjusted models, to model this change as a function of sociodemographic and program-specific covariates, such as number of clinical visits and value of prescription redemption.ResultsWe found a dose propensity-adjusted increase of 0.32 cups (95% confidence interval, 0.19-0.45 cups) for each additional visit while holding constant the predicted number of visits and site. An equal portion of the change-score increase was attributed to vegetable consumption and fruit consumption (β = 0.16 for each).ConclusionFruit and vegetable prescription programs in clinical settings may increase fruit and vegetable consumption among children in low-income households. Future research should use a comparison group and consider including qualitative analysis of site-specific barriers and facilitators to success

The Effect of Emotional Intelligence and Task Type on Malevolent Creativity

Malevolent creativity (MC), or intending to inflict harm in original ways, is an aspect of creativity that has received little empirical attention. It reasons that generating malevolently creative products in response to a problem is dependent upon individual differences and environmental factors, especially with regard to the social and emotional content of a particular problem. A personality variable strongly associated with how individuals acknowledge and respond to such social and emotional content is emotional intelligence (EI). Individuals with higher EI often solve problems in cooperative, beneficial, and positive ways, which seems contrary to solving a problem with MC. In addition to testing whether EI is negatively related to MC in general, we analyzed whether that negative relationship would persist even after controlling for cognitive ability and task effects. Those questions were examined across two studies. Results suggest that individuals with lower EI are more likely to respond to different types of problems with increased instances of MC even when the social or emotional content of those problems are factored out. The implications and limitations of these studies, as well as future directions for the study of MC, are discussed

Statistical Properties of Avalanches in Networks

We characterize the distributions of size and duration of avalanches propagating in complex networks. By an avalanche we mean the sequence of events initiated by the externally stimulated `excitation' of a network node, which may, with some probability, then stimulate subsequent firings of the nodes to which it is connected, resulting in a cascade of firings. This type of process is relevant to a wide variety of situations, including neuroscience, cascading failures on electrical power grids, and epidemology. We find that the statistics of avalanches can be characterized in terms of the largest eigenvalue and corresponding eigenvector of an appropriate adjacency matrix which encodes the structure of the network. By using mean-field analyses, previous studies of avalanches in networks have not considered the effect of network structure on the distribution of size and duration of avalanches. Our results apply to individual networks (rather than network ensembles) and provide expressions for the distributions of size and duration of avalanches starting at particular nodes in the network. These findings might find application in the analysis of branching processes in networks, such as cascading power grid failures and critical brain dynamics. In particular, our results show that some experimental signatures of critical brain dynamics (i.e., power-law distributions of size and duration of neuronal avalanches), are robust to complex underlying network topologies.Comment: 11 pages, 7 figure

Nonequilibrium capillary self-assembly

Macroscopic objects supported by surface tension at the fluid interface can self-assemble through the action of capillary forces arising from interfacial deformations. The resulting self-assembled structures are ordered but remain trapped in one of potentially many metastable states in the capillary energy landscape. This contrasts with microscopic colloidal self-assembly where thermal fluctuations excite transitions between geometrically distinct ground-state configurations. We herein utilize supercritical Faraday waves to drive structural rearrangements between metastable states of few-particle clusters of millimetric spheres bound by capillary attractions at the fluid interface. Using a combination of experiments and theoretical modelling, we demonstrate how the occupation probabilities of different cluster topologies and transition statistics are controlled by the level of the vibrational forcing and the spatial extent of long-range capillary forces. Our results demonstrate how self-assembly dynamics and statistics may be manipulated across scales by controlling the strength of fluctuations and by tuning the properties of the particle interaction-potential

Is there a correlation between infection control performance and other hospital quality measures?

Quality measures are increasingly reported by hospitals to the Centers for Medicare and Medicaid Services (CMS), yet there may be tradeoffs in performance between infection control (IC) and other quality measures. Hospitals that performed best on IC measures did not perform well on most CMS non–IC quality measures