Output characteristics of tidal current power stations

With increasing targets being set for renewable-derived electricity generation, wind power is currently the preferred technology. It is widely accepted that due to the stochastic nature of wind, there is an upper limit to the capacity that can be accommodated within the electricity network before power quality is impeded. This paper demonstrates the potential of tidal energy as a predictable renewable technologies that can be developed for base load power generation and thus minimise the risk of compromising future power quality

Improved Reinforcement Learning with Curriculum

Humans tend to learn complex abstract concepts faster if examples are presented in a structured manner. For instance, when learning how to play a board game, usually one of the first concepts learned is how the game ends, i.e. the actions that lead to a terminal state (win, lose or draw). The advantage of learning end-games first is that once the actions which lead to a terminal state are understood, it becomes possible to incrementally learn the consequences of actions that are further away from a terminal state - we call this an end-game-first curriculum. Currently the state-of-the-art machine learning player for general board games, AlphaZero by Google DeepMind, does not employ a structured training curriculum; instead learning from the entire game at all times. By employing an end-game-first training curriculum to train an AlphaZero inspired player, we empirically show that the rate of learning of an artificial player can be improved during the early stages of training when compared to a player not using a training curriculum.Comment: Draft prior to submission to IEEE Trans on Games. Changed paper slightl

Small molecules based on novel electron-deficient acceptor units for organic electronic applications

Demand for photovoltaic cells is ever-increasing due to the diminishing supply of oil-based fuels and the associated harmful environmental effects. Organic photovoltaic devices offer a light and flexible alternative to Si-based PVs. In addition to this, they can be processed using fabrication methods such as spin-coating and inkjet printing hence, such devices have potential to be produced cheaply on a large scale. Although they have been applied as donor materials with success, polymers often show end-group variation and are polydisperse so there can be batch-to-batch variation with respect to OPV performance. A solution to these problems is the use of small donor molecules which are monodisperse and have well-defined structures. However, the shorter conjugation of small molecules with respect to polymers requires measures to shorten the HOMO-LUMO gap. A common approach is the incorporation of electron-deficient acceptor units into the donor molecule, lowering the LUMO level and therefore the HOMO-LUMO gap.Chapter 1 reviews band theory, the development of organic semiconductors, including a summary of oligothiophene based materials and common electron-deficient acceptor units used, the principles behind OPV and OFET devices and how organic semiconductors can be optimised in order to produce the best working devices.The synthesis, physical properties and OPV performance of materials based on naphthyridine-2,6-dione acceptor unit are presented in chapter 2, focussing on the difference between compounds with Donor-Acceptor-Donor and Acceptor-Donor-Acceptor structures. Chapter 3 shows the novel naphthyridin-2-one moiety and the synthesis of materials containing the unit and how they have been used for different applications including ambipolar OFETs and both donor and acceptor materials for bulk heterojunction OPV devices.A study in improving the mobility of OFET devices is presented in chapter 4. Different inorganic nanoparticles were added to organic semiconductor solutions for and the effect of this simple process on the performance of the OFET devices is discussed.Chapter 5 introduces the thieno[3,2-b]thiophene-2,5-dione and novel furo[3,2-b]furan-2,5-dione acceptor units. The synthesis, optical and electrochemical properties, and OFET and OPV device optimisation of materials based on these moieties are presented and discussed.A summary of the work discussed is presented in chapter 6 whilst chapter 7 presents the experimental methods for electrochemistry, device work, and synthetic procedures for each compound presented in Chapters 2, 3, 4 and 5Demand for photovoltaic cells is ever-increasing due to the diminishing supply of oil-based fuels and the associated harmful environmental effects. Organic photovoltaic devices offer a light and flexible alternative to Si-based PVs. In addition to this, they can be processed using fabrication methods such as spin-coating and inkjet printing hence, such devices have potential to be produced cheaply on a large scale. Although they have been applied as donor materials with success, polymers often show end-group variation and are polydisperse so there can be batch-to-batch variation with respect to OPV performance. A solution to these problems is the use of small donor molecules which are monodisperse and have well-defined structures. However, the shorter conjugation of small molecules with respect to polymers requires measures to shorten the HOMO-LUMO gap. A common approach is the incorporation of electron-deficient acceptor units into the donor molecule, lowering the LUMO level and therefore the HOMO-LUMO gap.Chapter 1 reviews band theory, the development of organic semiconductors, including a summary of oligothiophene based materials and common electron-deficient acceptor units used, the principles behind OPV and OFET devices and how organic semiconductors can be optimised in order to produce the best working devices.The synthesis, physical properties and OPV performance of materials based on naphthyridine-2,6-dione acceptor unit are presented in chapter 2, focussing on the difference between compounds with Donor-Acceptor-Donor and Acceptor-Donor-Acceptor structures. Chapter 3 shows the novel naphthyridin-2-one moiety and the synthesis of materials containing the unit and how they have been used for different applications including ambipolar OFETs and both donor and acceptor materials for bulk heterojunction OPV devices.A study in improving the mobility of OFET devices is presented in chapter 4. Different inorganic nanoparticles were added to organic semiconductor solutions for and the effect of this simple process on the performance of the OFET devices is discussed.Chapter 5 introduces the thieno[3,2-b]thiophene-2,5-dione and novel furo[3,2-b]furan-2,5-dione acceptor units. The synthesis, optical and electrochemical properties, and OFET and OPV device optimisation of materials based on these moieties are presented and discussed.A summary of the work discussed is presented in chapter 6 whilst chapter 7 presents the experimental methods for electrochemistry, device work, and synthetic procedures for each compound presented in Chapters 2, 3, 4 and

The implementation of discrete demand management algorithms within energy systems modelling

Traditionally, demand side management (DSM) programs have been driven by utilities. With the prospect of growth in the utilization of building-integrated micro-generation, DSM offers opportunities for additional energy savings and CO2 emission reductions through better utilisation of local renewable energy resources. This paper examines the feasibility of using discreet demand management (DDM) to improve the supply/demand match. For many combinations of micro-generation and DDM controls, it is necessary to know the environmental conditions (i.e. temperatures and lighting levels) within the buildings being modelled. One method would be to embed all the renewable energy technologies and DDM algorithms within a detailed simulation program. An alternative method, investigated in this study, involves coupling two existing tools: a dynamic building simulation program (ESP-r) and a demand/supply matching program (MERIT) that incorporates DDM algorithms and renewable energy system technologies. These two programs interact at the time-step level and exchange calculated parameters (relating to loads, supply potentials and prevailing environmental conditions) to enable an evaluation of DDM techniques in terms of energy saving and occupant impact. This paper describes the technique and presents simulation results relating to a number of building cases

A Combined Molecular Dynamics and Density Functional Theory Approach for Generating Liquid Water Configurations for Aqueous-Phase Heterogeneous Catalysis Studies

Aqueous-phase heterogeneous catalysis is an important chemical process in applications such as water remediation, fuel cells, and the production of fuels and chemicals, including from biomass sources. However, designing alternative, improved catalyst materials for these applications is difficult due to fluctuations in the solvation environment surrounding the catalytic species. In order to elucidate the thermodynamics and kinetics of the relevant reactions, it is imperative to gain a better understanding of the roles of liquid water molecules in these reactions. In this work, a method combining both classical and quantum simulations was developed to generate configurations of liquid water molecules over catalytic species adsorbed on a catalyst surface, which can provide valuable insight into the roles of the liquid water reaction environment on aqueous-phase heterogeneous catalysis. The method developed in this work entails combining force field molecular dynamics (FFMD) and density functional theory (DFT) simulations. This method leverages the strengths of each type of simulation to enable the calculation of catalytic energies under “realistic” liquid water configurations. FFMD simulations are used to generate trajectories of liquid water configurations that include thermal fluctuations, while DFT simulations are used to capture the energies associated with bond breaking and forming that are required for microkinetic modeling and catalyst design studies. This FFMD-DFT method was used to calculate the interaction energies between the liquid water environment and the reaction intermediate or transition state species. The trend in the calculated interaction energies was shown to correlate with the trend in hydrogen-bond formation between liquid water molecules and the catalytic species. This work also demonstrated that entropic effects due to the thermal fluctuations in the solvation environment are a significant contribution to the free energies calculated for aqueous-phase, heterogeneously-catalyzed systems. The FFMD-DFT method was also used to calculate reaction energies, activation barriers, and pre-exponential factors to study the kinetics of example O—H and C—H cleavage reactions on a platinum catalyst surface under an aqueous reaction environment. Using this method, it was found that O—H cleavage reactions prefer H2O-mediated pathways, while C—H cleavage reactions prefer non-H2O-mediated pathways. In summary, the FFMD-DFT method developed in this work has been shown to be a robust technique for generating realistic liquid water configurations over catalytic species on a platinum catalyst surface. Those liquid water configurations can be used to calculate catalytic properties that can provide insight into the roles of water molecules in these reactions and facilitate microkinetic modeling and catalyst design studies

Optimal strategies for sustainable household organic material management in the city of Rochester, NY

The purpose of this research was to explore the benefits and challenges of implementing a sustainable system for managing household organic material (HHOM) in the city of Rochester, NY. Elsewhere in the United States and the world, HHOM (i.e. excess food, yard matter, and compostable paper) has been increasingly diverted from landfills to organic waste-to-energy and composting pathways (European Environment Agency 2013a; Skumatz and Freeman 2006). Landfill diversion is enabled by municipal projects that support source separation of HHOM out of the municipal solid waste (MSW) stream, thereby extracting valuable organic resources for higher-value processing (NYSDEC 2010). This has been done to increase the profitability of HHOM management (Eriksson et al. 2005) while simultaneously achieving benefits to the environment (e.g. life-cycle greenhouse gas reductions) (Ebner et al., 2014; Sanscartier et al. 2012; Environmental Protection Agency 2013c) and society (e.g. community resilience; food security; local agriculture) (Sundkvist et al. 2001; Curtis 2003; Jansson 2013; Colding and Barthel 2013). In recent years, only 10% of the 27,000 Metric Tons (MT) of HHOM in the city of Rochester has been diverted from landfills (NYSDEC 2008). It was hypothesized in this research that an effectively planned and implemented municipal project designed to increase processing of HHOM in organic waste-to-energy or composting pathways would sustainably bolster economic, social, and environmental assets in the city of Rochester, NY. The first step in testing this assertion involved gathering data on the social sustainability of a project utilizing source separated HHOM. Surveys and interviews of potential project participants in the Southeast section of the city of Rochester, NY were conducted to examine residents\u27 a) likelihood of project participation, b) economic incentives to reduce MSW generation and HHOM 4 source separation, c) current HHOM management behaviors, and d) awareness of available HHOM management pathways. Resident survey and interview responses indicated that residents are likely to reduce MSW generation and to participate in curbside collection of source separated HHOM, as long as these goals are incentivized. In addition, composting was found to be the most well-known pathway for HHOM management. Additional education is required to increase awareness of the other pathways for managing HHOM, yet residents indicated that they are interested in purchasing pathway products (i.e. locally produced energy and compost). The survey and interview data indicated a need for incentivizing sustainable HHOM management behaviors. Thus, it was essential to determine the most cost-effective municipal project to drive source separation of HHOM. A literature review was conducted of projects in locales achieving high landfill diversion of HHOM to identify the best policy options. The findings indicated that the ideal project to support source separation of HHOM in Rochester, NY is weight-based MSW pricing (also known as pay-as-you-throw) with free organic collection. The financial impacts of implementing a pay-as-you-throw (PAYT) project in the city of Rochester, NY were analyzed using a cost-benefit analysis (CBA). Development of the CBA model addressed the uncertainty in the financial impacts of implementing the PAYT project by conducting the analysis for multiple scenarios of key parameters such as actual resident HHOM source separation and MSW reduction behaviors. Data required to build scenarios was based on documented source separation and MSW generation performance for new and established PAYT projects. For each scenario, optimal MSW prices were found where municipal budget was maximized without reducing the average household budget. Then, project net present value was calculated. Weight-based PAYT project net present value (NPV) to the municipal solid waste collection budget for the City of Rochester Department of Environmental Services was calculated. The project NPV is between $12,100,000 and$18,100,000, with a projected increase in average city household budget over the 11 year project life. The project was shown to have annual positive net cash flows between $1,300,000 under a conservative MSW source reduction scenario and$2,100,000 with an optimistic source reduction scenario. At current City of Rochester solid waste collection budget levels of $17,300,000, the project would reduce annual expenditures by 8The surveys, interviews, and CBA showed the promise of implementing a project to utilize source separated HHOM. However, it remained unclear what local pathways were economically optimal (i.e. profit-maximizing) for processing excess food, compostable paper, and yard trimming feedstocks from households in the city of Rochester, NY. The product yields, costs, and revenues are 5 different for HHOM processing pathways, and can depend on the chemical properties of feedstocks. Due to these uncertainties, investment in sustainable HHOM infrastructure could be stymied unless the most profitable HHOM management pathways are identified. This was investigated by creating an engineering-economic model using the What\u27sBEST! Add-in for Microsoft Excel. The model looked at four management pathways for source separated HHOM: landfills with gas capture (i.e. status quo for Rochester, NY), plus anaerobic digestion (AD), simultaneous saccharification and fermentation (SSF), and windrow composting. Model indicators included pathway revenues (e.g. product sales and tipping fees), pathway costs (e.g. trucking, capital, operations), as well as feedstock chemical parameters. Empirical data was collected for biomethane potential (mL CH4 /g volatile solids) of representative HH food and compostable paper material using gas chromatography. Baseline results indicate that$3,000,000 in profit can be made from HHOM with profit-maximizing processing pathways. In the baseline, anaerobic digestion was optimal for food, SSF was optimal for yard trimmings, and composting was optimal for compostable paper. Landfills with gas capture were not economically optimal for the HHOM feedstocks. In the case of a single-stream HHOM collection scheme, the baseline model shows that anaerobic digestion is the most profitable pathway. Sensitivity analysis showed that product revenues were the primary drivers of profitability among profit-maximizing HHOM pathways. On the other hand, pathway tipping fees and feedstock trucking costs have a relatively minimal impact on profits. This research showed that updating HHOM management policy and practice in the city of Rochester, NY will maximize local environmental, social, and economic performance. This can and should be achieved with the expansion of AD, composting, and SSF infrastructure in place of landfills with gas capture

Sinking of Crude Oil Amended-Model Oil Mixtures Due to Evaporative or Dissolution Weathering on the Surface and Submerged in Water

Despite the popular belief that crude oil is a mixture of hydrocarbons that floats on the surface of water, tar balls continue to wash up on beaches from the sea floor years after the Deep Water Horizon oil spill. This is because of the rarely studied weathering effects that occur during deep sea spills. While the evaporative weathering process of oil at the water’s surface has been studied, no currently implemented models assess the weathering effects of dissolution within the water column. The evaporative effects at the sea surface and the dissolution of soluble components within droplets located in the water column leave a heavy fraction of oil that may sink. Laboratory experiments from previous work used hydrocarbon-like chemicals to form binary model oils. In contrast, experiments presented in this work use crude oil amended model oil (COA-MO) mixtures where the sinking of heavy fractions of crude oil does occur. The evaporative weathering binary model, when applied to COA-MO mixtures, was able to predict the sinking times of oil droplets using physical data of the three individual components of the mixture (crude oil, a light volatile, and heavy non-volatile chemical). The dissolution bonary model was able to predict the sinking times of COA-MO mixtures while submerged under water. A range of experimentally derived dissolution time constant, K, was obtained which could be applied to a broad spectrum of real world oils where the solubility of individual crude oil components varies greatly

The Effectiveness of Code-Switching in Evangelism: The Use of African American Vernacular English by Standard English Speakers

Abstract This paper evaluates the use of code-switching as a linguistic and pragmatic tool to build interpersonal relationships between members of the African American minority group and the Standard English “white majority” for the purpose to evangelize the Christian faith. Using the Shannon-Weaver (Shannon & Weaver, 1999) communication model as a foundation, the research suggests that changing the message is the best way to overcome barriers in interpersonal communication (namely evangelistic communication). The research varies in use of code-switching as a pragmatic tool for this message change. Ariffin (2009), Jørgensen (1998), and Madsen (2004) give positive evidence for code-switching, while Anderson (2007) contrastingly argues that lexical borrowing is more favorable, and Wilder (1984) argues that cultural typicalness is most favorable. This research analyzes code-switching in an inner city teen center by reviewing questionnaires from the out-group volunteers and interviewing a volunteer with dual in-group membership. The original hypothesis states that the use of code-switching has a neutral to positive effect on building credible relationships between the majority out-group and minority in-group and thereby would be an effective evangelistic tool. However, the questionnaires and the interview reveal a neutral to negative effect of code-switching which supports the arguments of Wilder (1984) and Anderson (2007). Keywords: code-switching, evangelism, African American Vernacular English (AAVE), Shannon-Weave

Energy and carbon performance of housing : upgrade analysis, energy labelling and national policy development

The area of policy formulation for the energy/carbon performance of housing is coming under increasing focus. A major challenge is to account for the large variation within national housing stocks relative to factors such as location, climate, age, construction, previous upgrades, appliance use and heating/cooling system types. Existing policy oriented tools rely on static calculation models that have limited ability to represent building behaviour and the impact of future changes in climate and technology. The switch to detailed simulation tools to address these limitations in the context of policy development has hitherto been focussed on the modelling of a small number of representative designs rather than dealing with the spread inherent in large housing stocks. To address these challenges, the ESRU Domestic Energy Model (EDEM) has been developed as a Web based tool built on detailed simulation models that have been aligned with the outcomes of national house condition surveys. On the basis of pragmatic inputs, EDEM is able to determine energy use and carbon emissions at any scale – from an individual dwelling to national housing stocks. The model was used at the behest of the Scottish Building Standards Agency and South Ayrshire Council to determine the impact of upgrades and the deployment of new and renewable energy systems. EDEM was also used to rate the energy/carbon performance of individual dwellings as required by the EU Directive on the Energy Performance of Buildings (EU, 2002). This paper describes the EDEM methodology and presents the findings from applications at different scales

Characterization and Commissioning of a Ka-Band Ground Station for Cognitive Algorithm Development

In 2018, the Cognitive Communications and Propagation projects completed installation and checkout testing of a new Ka-Band ground station at the NASA Glenn Research Center in Cleveland, Ohio. The Cognitive Algorithms Demonstration Testbed (CADeT) was developed to provide a fully characterized and controllable dynamic link environment to researchers looking to demonstrate hardware and software aligned with atmospheric sensing and cognitive algorithms. CADeT integrates a host of precision control and measurement systems in addition to repurposing a 5.5 meter beam-waveguide dish platform previously used with the Advanced Communications Technology Satellite (ACTS). This paper will discuss the laboratory testing of ground station components with a emphasis on elements vital to achieving link budget requirements including characterization of the new Gallium Nitride (GaN) Solid State Power Amplifier (SSPA) and far-field measurements of the new antenna feed. Finally, the paper discusses in-situ tests conducted with CADeT and the Tracking and Data Relay Satellite System (TDRSS) to validate laboratory results and make necessary link budget adjustments before reviewing the lessons learned