http://hdl.handle.net/10468/460 Mon, 30 Oct 2017 00:16:16 GMT 2017-10-30T00:16:16Z http://hdl.handle.net/10468/3618 Photocatalytic air-purification: A low-cost, real-time gas detection method Keane, Donal A.; Hamilton, Niki; Gibson, Lorraine T.; Pillai, Suresh C.; Holmes, Justin D.; Morris, Michael A. This research demonstrates the use of a gas detector as a feasible alternative to the standardized analytical methods typically found in photocatalytic air-purification ISO standard tests and academic literature. A methyl mercaptan detector is calibrated and validated (for linearity) using a standard gas generator. The detector can be directly connected to the photoreactor exit allowing real-time span gas measurement with data-logging at one minute intervals. The detector successfully differentiated samples with different photocatalytic performance. The use of such detectors offers an easy-to-use, low-cost alternative to gas measurement with applications in academic research, proof-of-concept photocatalytic tests and also as an educational tool. Fri, 01 Dec 2017 00:00:00 GMT http://hdl.handle.net/10468/3618 2017-12-01T00:00:00Z http://hdl.handle.net/10468/3554 Gas- and particle-phase products from the photooxidation of acenaphthene and acenaphthylene by OH radicals Riva, Matthieu; Healy, Robert M.; Flaud, Pierre-Marie; Perraudin, Emilie; Wenger, John C.; Villenave, Eric This work is focused on the gas-phase oxidation of acenaphthylene and acenaphthene by OH radicals and associated secondary organic aerosol (SOA) formation under low and high-NOx conditions. Experiments were carried out in an atmospheric simulation chamber using a proton transfer reaction time-of-flight-mass spectrometer (PTR-TOF-MS) and an aerosol time-of-flight-mass spectrometer (ATOFMS) to chemically characterize the gas- and particle-phase products, respectively. Due to the structures of these two aromatic compounds, the proposed chemical mechanisms exhibit some differences. In the case of acenaphthene, H-atom abstraction from the saturated cyclopenta-fused ring was found to be competitive with the OH-addition to the aromatic rings. During the photooxidation of acenaphthene using nitrous acid (HONO), aromatic ring-opening products such as indanone and indanone carbaldehyde, generated through OH addition to the aromatic ring, were formed in higher yields compared to low-NOx conditions. In the case of acenaphthylene, OH addition to the unsaturated cyclopenta-fused ring was strongly favored. Hence, ring-retaining species such as acenaphthenone and acenaphthenequinone, were identified as the main reaction products in both gas- and particle-phases, especially under high-NOx conditions. Subsequent SOA formation was observed in all experiments and SOA yields were determined under low/high-NOx conditions to be 0.61/0.46 and 0.68/0.55 from the OH-initiated oxidation of acenaphthylene and acenaphthene, respectively. Thu, 30 Nov 2017 00:00:00 GMT http://hdl.handle.net/10468/3554 2017-11-30T00:00:00Z http://hdl.handle.net/10468/4702 The effect of model inaccuracy and move-blocking on the performance of a wave-to-wire wave energy converter , under economic predictive control O'Sullivan, Adrian C. M.; Lightbody, Gordon In this paper, an economic Model Predictive Control (MPC) is used to investigate the effects that arise from the model mismatch between the control and the system. It is shown that the average electrical power is affected by the modelling discrepancies, but that the performance is still acceptable. A move-blocking technique is incorporated into the structure of the control horizon of the MPC, where the move-blocking decreases the computational burden whilst maintaining system performance, hence drastically reducing the optimisation solving time. The MPC with the move-blocking incorporated is then tested on the most significant mismatch, where it is shown that the control horizon of the MPC can be drastically reduced while maintaining system performance. Wed, 30 Aug 2017 00:00:00 GMT http://hdl.handle.net/10468/4702 2017-08-30T00:00:00Z http://hdl.handle.net/10468/4777 Comparison of pre-treatments to reduce salinity and enhance biomethane yields of Laminaria digitata harvested in different seasons Tabassum, Muhammad Rizwan; Xia, Ao; Murphy, Jerry D. Pre-treatment can enhance anaerobic digestion of seaweed; however, seasonal variation in the biochemical composition of seaweed has a significant impact on the pre-treatment effect. In this study, various pre-treatments were employed for the brown seaweed Laminaria digitata harvested in March (with high ash content and low carbon to nitrogen (C:N) ratio) and September (with low ash content and high C:N ratio). Washing of L. digitata harvested in March with hot water (defined as 40 °C) removed 54% of the ash and improved the volatile solids (VS) content by 31% leading to an improved biomethane yield of 282 L CH4 kg VS−1. This pre-treatment affected a 16% increase in biodegradability, reduced salt accumulation in the digestate by 54%, and increased specific methane yield per wet weight by 25%. This level of effect was not noted for seaweed harvested in September, when the biodegradability is higher. Wed, 16 Aug 2017 00:00:00 GMT http://hdl.handle.net/10468/4777 2017-08-16T00:00:00Z