The development of a computer model to optimize the performance of a 50kWp photovoltaic system

A computer model has been developed to optimize the performance of a 50kWp photovoltaic system which supplies electrical energy to a dairy farm at Fota Island in Cork Harbour. Optimization of the system involves maximising the efficiency and increasing the performance and reliability of each hardware unit. The model accepts horizontal insolation, ambient temperature, wind speed, wind direction and load demand as inputs. An optimization program uses the computer model to simulate the optimum operating conditions. From this analysis, criteria are established which are used to improve the photovoltaic system operation. This thesis describes the model concepts, the model implementation and the model verification procedures used during development. It also describes the techniques which are used during system optimization. The software, which is written in FORTRAN, is structured in modular units to provide logical and efficient programming. These modular units may also be used in the modelling and optimization of other photovoltaic systems.

Obstetric mode of delivery and child psychological development

Background/aims: Objective of the current thesis is to investigate the potential impact of birth by Caesarean section (CS) on child psychological development, including autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), behavioural difficulties and school performance. Structure/methods: Published literature to date on birth by CS, ASD and ADHD was reviewed (Chapter 2). Data from the UK Millennium Cohort Study (MCS) were analysed to determine the association between CS and ASD, ADHD and parent-reported behavioural difficulties (Chapter 3). The Swedish National Registers were used to further assess the association with ASD, ADHD and school performance (Chapters 4-6). Results: In the review, children born by CS were 23% more likely to be diagnosed with ASD after controlling for potential confounders. Only two studies reported adjusted estimates on the association between birth by CS and ADHD, results were conflicting and limited. CS was not associated with ASD, ADHD or behavioural difficulties in the UK MCS. In the Swedish National Registers, children born by CS were more likely to be diagnosed with ASD or ADHD. The association with elective CS did not persist when compared amongst siblings. There was little evidence of an association between birth by elective CS and poor school performance. Children born by elective CS had slight reduction in school performance. Conclusions: The lack of association with the elective CS in the sibling design studies indicates that the association in the population is most probably due to confounding. A small but significant association was found between birth by CS and school performance. However, the effect may have been due to residual confounding or confounding by indication and should be interpreted with caution. The overall conclusion is that birth by CS does not appear to have a causal relationship with the aspects of child psychological development investigated.