338 research outputs found

    Coordinated operation of electric vehicle charging and wind power generation as a virtual power plant: A multi-stage risk constrained approach

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    © 2019 Elsevier Ltd As the number of electric vehicles (EVs) is steadily increasing, their aggregation can offer significant storage to improve the electric system operation in many aspects. To this end, a comprehensive stochastic optimization framework is proposed in this paper for the joint operation of a fleet of EVs with a wind power producer (WPP) in a three-settlement pool-based market. An aggregator procures enough energy for the EVs based on their daily driving patterns, and schedules the stored energy to counterbalance WPP fluctuations. Different sources of uncertainty including the market prices and WPP generation are modeled through proper scenarios, and the risk is hedged by adding a risk measure to the formulation. To obtain more accurate results, the battery degradation costs are also included in the problem formulation. A detailed case study is presented based on the Iberian electricity market data as well as the technical information of three different types of EVs. The proposed approach is benchmarked against the disjoint operation of EVs and WPP. Numerical simulations demonstrate that the proposed strategy can effectively benefit EV owners and WPP by reducing the energy costs and increasing the profits

    A hybrid unsupervised approach toward EEG epileptic spikes detection

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    Epileptic spikes are complementary sources of information in EEG to diagnose and localize the origin of epilepsy. However, not only is visual inspection of EEG labor intensive, time consuming, and prone to human error, but it also needs long-term training to acquire the level of skill required for identifying epileptic discharges. Therefore, computer-aided approaches were employed for the purpose of saving time and increasing the detection and source localization accuracy. One of the most important artifacts that may be confused as an epileptic spike, due to morphological resemblance, is eye blink. Only a few studies consider removal of this artifact prior to detection, and most of them used either visual inspection or computer-aided approaches, which need expert supervision. Consequently, in this paper, an unsupervised and EEG-based system with embedded eye blink artifact remover is developed to detect epileptic spikes. The proposed system includes three stages: eye blink artifact removal, feature extraction, and classification. Wavelet transform was employed for both artifact removal and feature extraction steps, and adaptive neuro-fuzzy inference system for classification purpose. The proposed method is verified using a publicly available EEG dataset. The results show the efficiency of this algorithm in detecting epileptic spikes using low-resolution EEG with least computational complexity, highest sensitivity, and lesser human interaction compared to similar studies. Moreover, since epileptic spike detection is a vital component of epilepsy source localization, therefore this algorithm can be utilized for EEG-based pre-surgical evaluation of epilepsy

    A framework to identify and prioritise the key sustainability indicators: Assessment of heating systems in the built environment

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    Sustainability indicators (SIs) are important instruments to quantify, analyse, and communicate complex sustainability information, with a history of application in energy research. It is critical to identify an effective set of indicators which can holistically evaluate the energy systems encompassing the three facets of sustainability: environment, economy, and society. However, the literature has been lacking in either proportionally representing the sustainability dimensions or reflecting the stakeholders’ preferences. This paper develops a framework to identify and prioritise a set of SIs, critically reviewed to ensure reflection of a wide array of factors and conceptions of what sustainability entails. The developed framework utilises a series of methods within three phases: identification, refinement, and prioritisation. Applying the proposed framework to building heating technologies, a set of 22 SIs consisting of 4 economic, 8 environmental, and 10 social indicators were identified. According to the results, the economic indicators of Operation & Maintenance Cost and Net Present Value were found to be the most impactful factors, while environmental SIs contribute the most to the overall sustainability weight. The identified indicators apply to the assessment of heating systems and policies, and the proposed framework could more broadly support analysis of key sustainability criteria in various fields

    Planning energy interventions in buildings and tackling fuel poverty: Can two birds be fed with one scone?

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    Energy retrofitting and renovations are an inseparable part of decarbonisation strategies in the building sector. These measures are often tied up with several social factors that can potentially impact the wellbeing of households and the community if the end-user requirements are not carefully considered. Fuel poverty is one of these social factors that is an essential consideration for designing effective, just, and user-centred interventions, but it is often overlooked in engineering processes. Therefore, this article seeks to re-connect the notion of fuel poverty to practice by bringing it forward from the post-intervention assessments to the design and decision-making stages. To do so, a new indicator, Potential Fuel Poverty Index (PFPI), is developed to obtain the likelihood of fuel poverty that future interventions can pose to the households. The PFPI presents a more targeted analysis of fuel poverty by reflecting the socio-spatial characterisation of the households. Using the PFPI, fuel poverty can be observed as a design/decision factor at the early stages of sketching interventions, in conjunction with other economic, environmental, and technical factors. Finally, the utility of the developed method is demonstrated using a real case study in the UK, assessing the impact of heat decarbonisation through heat pumps on fuel poverty

    Serum testosterone levels of HbSS (sickle cell disease) male subjects in Lagos, Nigeria

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    <p>Abstract</p> <p>Background</p> <p>Infertility is a major problem in sickle cell disease patients, especially in males. In addition to low serum testosterone, other abnormalities involving the accessory sex organs, such as the seminal vesicles and the prostate gland, as well as marked decrease in ejaculate volume may be observed in male HbSS patients. Hence, the need to study the role of sex hormones as a cause of infertility in male HbSS patients.</p> <p>Methods</p> <p>An unmatched case-control study was performed using seventy-five consenting subjects from Lagos University Teaching Hospital. These included 47 patients with haemoglobin phenotype SS from the Sickle cell clinic and 28 volunteered medical students and members of staff with haemoglobin phenotype AA. Demographic data were obtained using a self-administered questionnaire. A total of 5 mls of blood was collected from each subject between 9.00 am & 11.am, and assayed for serum testosterone concentration.</p> <p>Results</p> <p>The concentrations of serum testosterone in HbSS patients ranged from 0.2 to 4.3 ng/ml with a mean of 1.28 ± 0.72 ng/ml whilst the values in HbAA controls ranged from 1.2 to 6.9 ng/ml with a mean of 2.63 ± 1.04 ng/ml. Seven (25.0%) of the 28 controls had serum testosterone concentration lower than the quoted reference (normal) range whereas 44 (93.6%) of the 47 HbSS subjects had serum testosterone concentration lower than the reference range.</p> <p>Conclusion</p> <p>Overall, subjects with HbSS have significantly lower mean serum testosterone than HbAA controls.</p

    Hepatoprotective effects of methanol extract of Carissa opaca leaves on CCl4-induced damage in rat

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    <p>Abstract</p> <p>Background</p> <p><it>Carissa opaca </it>(Apocynaceae) leaves possess antioxidant activity and hepatoprotective effects, and so may provide a possible therapeutic alternative in hepatic disorders. The effect produced by methanolic extract of <it>Carissa opaca </it>leaves (MCL) was investigated on CCl<sub>4</sub>-induced liver damages in rat.</p> <p>Methods</p> <p>30 rats were divided into five groups of six animals of each, having free access to food and water <it>ad libitum</it>. Group I (control) was given olive oil and DMSO, while group II, III and IV were injected intraperitoneally with CCl<sub>4 </sub>(0.5 ml/kg) as a 20% (v/v) solution in olive oil twice a week for 8 weeks. Animals of group II received only CCl<sub>4</sub>. Rats of group III were given MCL intragastrically at a dose of 200 mg/kg bw while that of group IV received silymarin at a dose of 50 mg/kg bw twice a week for 8 weeks. However, animals of group V received MCL only at a dose of 200 mg/kg bw twice a week for 8 weeks. The activities of aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and γ-glutamyltransferase (γ-GT) were determined in serum. Catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), glutathione-S-transferase (GST), glutathione peroxidase (GSH-Px), glutathione reductase (GSR) and quinone reductase (QR) activity was measured in liver homogenates. Lipid peroxidation (thiobarbituric acid reactive substances; TBARS), glutathione (GSH) and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) concentration was also assessed in liver homogenates. Phytochemicals in MCL were determined through qualitative and high performance liquid chromatography (HPLC) analysis.</p> <p>Results</p> <p>Hepatotoxicity induced with CCl<sub>4 </sub>was evidenced by significant increase in lipid peroxidation (TBARS) and H<sub>2</sub>O<sub>2 </sub>level, serum activities of AST, ALT, ALP, LDH and γ-GT. Level of GSH determined in liver was significantly reduced, as were the activities of antioxidant enzymes; CAT, POD, SOD, GSH-Px, GSR, GST and QR. On cirrhotic animals treated with CCl<sub>4</sub>, histological studies showed centrilobular necrosis and infiltration of lymphocytes. MCL (200 mg/kg bw) and silymarin (50 mg/kg bw) co-treatment prevented all the changes observed with CCl<sub>4</sub>-treated rats. The phytochemical analysis of MCL indicated the presence of flavonoids, tannins, alkaloids, phlobatannins, terpenoids, coumarins, anthraquinones, and cardiac glycosides. Isoquercetin, hyperoside, vitexin, myricetin and kaempherol was determined in MCL.</p> <p>Conclusion</p> <p>These results indicate that MCL has a significant protective effect against CCl<sub>4 </sub>induced hepatotoxicity in rat, which may be due to its antioxidant and membrane stabilizing properties.</p

    Path analysis of the relationship between optimism, humor, affectivity, and marital satisfaction among infertile couples

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    Marital satisfaction is an important factor for establishing a family relationship, feeling satisfied, and living happily together. The aim of the present study was to investigate the relationship between optimism, humor, positive and negative affect, and marital satisfaction among infertile couples. The sample comprised 80 infertile Iranian couples (n = 160) who visited infertility clinics. Participants completed a series of Persian versions of psychometric scales related to optimism (Attributional Style Questionnaire), humor (Humor Styles Questionnaire), marital satisfaction (Enrich Marital Satisfaction Questionnaire), positive affect (PA) and negative affect (NA) (Positive and Negative Affect Schedule). The obtained result of Smart PLS statistical analysis confirmed the significant positive correlation between optimism and humor with marital satisfaction and high PA and low NA. Moreover, the findings also provided an adequate fit of the model. The findings demonstrated that infertile couples high in optimism and humor have higher levels of marital satisfaction and high PA and low PA. Based on the study’s findings, interventions for facilitating optimism and humor among infertile couples are discussed
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