755 research outputs found

    Distributed smart charging of electric vehicles for balancing wind energy

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    To meet worldwide goals of reducing CO2 footprint, electricity production increasingly is stemming from so-called renewable sources. To cater for their volatile behavior, so-called demand response algorithms are required. In this paper, we focus particularly on how charging electrical vehicles (EV) can be coordinated to maximize green energy consumption. We present a distributed algorithm that minimizes imbalance costs, and the disutility experienced by consumers. Our approach is very much practical, as it respects privacy, while still obtaining near-optimal solutions, by limiting the information exchanged: i.e. consumers do not share their preferences, deadlines, etc. Coordination is achieved through the exchange of virtual prices associated with energy consumption at certain times. We evaluate our approach in a case study comprising 100 electric vehicles over the course of 4 weeks, where renewable energy is supplied by a small scale wind turbine. Simulation results show that 68% of energy demand can be supplied by wind energy using our distributed algorithm, compared to 73% in a theoretical optimum scenario, and only 40% in an uncoordinated business-as-usual (BAU) scenario. Also, the increased usage of renewable energy sources, i.e. wind power, results in a 45% reduction of CO2 emissions, using our distributed algorithm

    Charging electric vehicles in the smart grid

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    Architectures for smart end-user services in the power grid

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    Abstract-The increase of distributed renewable electricity generators, such as solar cells and wind turbines, requires a new energy management system. These distributed generators introduce bidirectional energy flows in the low-voltage power grid, requiring novel coordination mechanisms to balance local supply and demand. Closed solutions exist for energy management on the level of individual homes. However, no service architectures have been defined that allow the growing number of end-users to interact with the other power consumers and generators and to get involved in more rational energy consumption patterns using intuitive applications. We therefore present a common service architecture that allows houses with renewable energy generation and smart energy devices to plug into a distributed energy management system, integrated with the public power grid. Next to the technical details, we focus on the usability aspects of the end-user applications in order to contribute to high service adoption and optimal user involvement. The presented architecture facilitates end-users to reduce net energy consumption, enables power grid providers to better balance supply and demand, and allows new actors to join with new services. We present a novel simulator that allows to evaluate both the power grid and data communication aspects, and illustrate a 22% reduction of the peak load by deploying a central coordinator inside the home gateway of an end-user

    The advanced activities of daily living: a tool allowing the evaluation of subtle functional decline in mild cognitive impairment

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    Objectives: Assessment of advanced activities of daily living (a-ADL) can be of interest in establishing the diagnosis of Alzheimer's disease (AD) in an earlier stage, since these activities demand high cognitive functioning and are more responsive to subtle changes. In this study we tested a new a-ADL tool, developed according to the International Classification of Functioning, Disability and Health (ICF). The a-ADL tool is based on the total number of activities performed (TNA) by a person and takes each subject as his own reference. It distinguishes a total Disability Index (a-ADL-DI), a Cognitive Disability Index (a-ADL-CDI), and a Physical Disability Index (a-ADL-PDI), with lower score representing more independency. We explored whether these indices allow distinction between cognitively healthy persons, patients with Mild Cognitive Impairment (MCI) and patients with mild AD. Methods: Participants were on average 80 years old (SD 4.6; 66-90), were community dwelling, and were diagnosed as (1) cognitively healthy subjects (n=26); (2) patients with MCI (n = 17), or (3) mild AD (n = 25), based upon extensive clinical evaluation and a set of global, cognitive, mood and functional assessments. The a-ADL-tool was not part of the clinical evaluation. Results: The a-ADL-CDI was significantly different between the three groups (p<.01). The a-ADL-DI was significantly different between MCI and AD (p<.001). The tool had good psychometrical properties (inter-rater reliability; agreement between patient and proxy; correlations with cognitive tests). Although the sample size was relatively small, ROC curves were computed for the a-ADL-DI and a-ADL-CDI with satisfactory and promising results. Conclusion: The a-ADL-CDI and a-ADL-DI might offer a useful contribution to the identification and follow up of patients with mild cognitive disorders in an older population

    Actinobacteria vs. Fusarium : battle of the toxins

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    Fusarium Head Blight (FHB) is a devastating disease in small-grain cereal, caused by the FHB species complex. Next to yield losses and deteriorated quality, the production of mycotoxins are a serious concern that challenges the global food chain. In a search for alternative methods to control mycotoxins in food and feed, the industry now turns to bacterial inoculants that prevent infection by toxigenic fungi, intervene when crops are being infected or remediate mycotoxin contaminated commodities. Actinobacteria harbour great potential for biocontrol and antifungal activity. In this study, 43 Rhodococcus spp. and 10 Streptomyces spp. were screened for their antifungal activity towards Fusarium graminearum, one of the most important species within the FHB species complex. After a preliminary study using a dual culture plate assay, strains that caused growth inhibition of the fungus were selected for further analysis. Remarkably, three S. rimosus strains caused complete growth inhibition, without any contact front. All three strains also significantly lowered the virulence of the GFP-tagged F. graminearum when applied on detached leaves and inhibited perithecia formation on wheat stubble. The S. rimosus strains were checked for the degradation and detoxification of two Fusarium mycotoxins: zearalenone (ZEN), produced as a defence mechanism, and deoxynivalenol (DON), an important virulence factor in FHB. All three strains showed 100% degradation and detoxification of ZEN. Results for DON degradation are currenlty being investigated. Degradation of these mycotoxins can not only give information regarding (one of multiple) biocontrol mechanisms, but also render the strains dual mode-of-action agents

    Distributed multi-agent algorithm for residential energy management in smart grids

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    Distributed renewable power generators, such as solar cells and wind turbines are difficult to predict, making the demand-supply problem more complex than in the traditional energy production scenario. They also introduce bidirectional energy flows in the low-voltage power grid, possibly causing voltage violations and grid instabilities. In this article we describe a distributed algorithm for residential energy management in smart power grids. This algorithm consists of a market-oriented multi-agent system using virtual energy prices, levels of renewable energy in the real-time production mix, and historical price information, to achieve a shifting of loads to periods with a high production of renewable energy. Evaluations in our smart grid simulator for three scenarios show that the designed algorithm is capable of improving the self consumption of renewable energy in a residential area and reducing the average and peak loads for externally supplied power

    The process of decline in advanced activities of daily living: a qualitative explorative study in mild cognitive impairment

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    Background: The notion of "minimal impairment in instrumental activities of daily living (i-ADL)" is important in the diagnosis of mild cognitive impairment (MCI), but is presently not adequately operationalized. ADL is stratified according to difficulty, complexity, and also to vulnerability to early cognitive changes in a threefold hierarchy: basic activities of daily living (b-ADL), i-ADL, and advanced activities of daily living (a-ADL). This study aims to gain a deeper understanding of the functional decline in the process of MCI. Methods: In a qualitative design, 37 consecutive patients diagnosed with amnestic (a)-MCI and their proxies were interviewed at two geriatric day hospitals. Constant comparative analysis was used for the analysis. Results: The a-ADL-concept emerged as important in the diagnosis of MCI. All participants were engaged in a wide range of activities, which could be clustered according to the International Classification of Functioning, Disability and Health (ICF). Participants reported subtle difficulties in performance. A process of functional decline was identified in which adaptation and coping mechanisms interacted with the process of reduced skills, leading to an activity disruption and an insufficiency in functioning. Conclusion: This study asserts the inclusion of an evaluation of a-ADL in the assessment of older persons. When evaluating ADL at three levels (b-ADL, i-ADL, and a-ADL), all the activities one can perform in daily living are covered

    Microbial detoxification of deoxynivalenol (DON), assessed via a Lemna minor L. bioassay, through biotransformation to 3-epi-DON and 3-epi-DOM-1

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    Mycotoxins are toxic metabolites produced by fungi. To mitigate mycotoxins in food or feed, biotransformation is an emerging technology in which microorganisms degrade toxins into non-toxic metabolites. To monitor deoxynivalenol (DON) biotransformation, analytical tools such as ELISA and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) are typically used. However, these techniques do not give a decisive answer about the remaining toxicity of possible biotransformation products. Hence, a bioassay using Lemna minor L. was developed. A dose-response analysis revealed significant inhibition in the growth of L. minor exposed to DON concentrations of 0.25 mg/L and higher. Concentrations above 1 mg/L were lethal for the plant. This bioassay is far more sensitive than previously described systems. The bioassay was implemented to screen microbial enrichment cultures, originating from rumen fluid, soil, digestate and activated sludge, on their biotransformation and detoxification capability of DON. The enrichment cultures originating from soil and activated sludge were capable of detoxifying and degrading 5 and 50 mg/L DON. In addition, the metabolites 3-epi-DON and the epimer of de-epoxy-DON (3-epi-DOM-1) were found as biotransformation products of both consortia. Our work provides a new valuable tool to screen microbial cultures for their detoxification capacity
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