121 research outputs found

    An Ant Colony Algorithm for HRES Size and Configuration Optimisation

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    Dispatch Strategy as a Design Variable in Hybrid Renewable Energy System Optimisation

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    Load mitigation of a class of 5-MW wind turbine with RBF neural network based fractional-order PID controller

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    Copyright © 2019 ISA. All rights reserved.Peer reviewedPostprin

    Capacity interaction in brick masonry under simultaneous in-plane and out-of-plane loads

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    A considerable number of numerical and experimental studies, carried out to-date to investigate the behaviour of masonry walls under seismic loading, have considered the in-plane or the out-of-plane response of the wall separately without due consideration for any possible interaction between the two responses. In this paper, the results of a series of tests with different levels of simultaneous in-plane shear and out-of-plane bending actions on small brick walls are presented. The tests results indicate noticeable interaction between the in-plane shear and out-of-plane bending strengths of brick walls. Test results are also used to validate representing numerical models of wall panels. The combined in-plane/out-of-plane capacity interaction in full-scale walls having different aspect ratios is then investigated using these numerical models. It is found that the wall aspect ratio highly influences the interaction level, which must be considered in masonry design

    Definition of interaction curves for the in-plane and out-of-plane capacity in brick masonry walls

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    During an earthquake a wall is subjected to a three dimensional acceleration field and undergoes simultaneous in-plane and out-of-plane loading. The action of one type of loading on the wall affects the strength of the wall against another type of loading. In this paper, a numerical investigation, supported by experiments, is conducted aimed at deriving appropriate relations for the in-plane/out-of-plane capacity interaction in unreinforced brick walls. Through a comprehensive parametric study, the main affecting parameters are recognized and their influences on the capacity interaction are established. The parametric study indicates that the aspect ratio of the wall and the elastic and inelastic material properties in tension have the most influence on the level of the in-plane and out-of-plane capacity interaction in masonry walls. Based on the results of these investigations, representing empirical analytical relations for evaluating the interaction are derived and their accuracy is verified

    Coupled thermo-electrical dispatch strategy with AI forecasting for optimal sizing of grid-connected hybrid renewable energy systems

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    In multi-energy systems the full utilisation of the generated energy is a challenge. Integrating heat and electricity supply at the system level design could provide an opportunity to address this challenge. In this paper we introduce and examine two coupled thermal-electrical dispatch strategies for grid-connected hybrid multi-energy systems supplying electrical and thermal demand loads. The dispatch strategy employs forecasting of energy resources and demand loads to prioritise supplying the thermal load in times of renewable surplus. Four forecasting algorithms, namely, baseline forecast, Facebook Prophet (FBP), Neural Prophet (NP), and Long Short-Term Memory model (LSTM) are implemented and used to generate annual forecast data for solar irradiance, wind speed, and thermal and electrical demand loads. To integrate forecast data within the dispatch strategy, new parameters are proposed to quantify the expected available energy within the forecast time horizon. A building complex for the Department of Education in the UK is used for conducting a system design case study. A genetic algorithm-based multi-objective optimisation with the levelised costs of electricity and heat as two objectives is conducted. The results show that the proposed dispatch algorithm produces systems with reduced levelised costs compared to the base case of using utility gas and electricity. Forecasting is particularly useful in reducing cost of heat, as it can prioritise supplying the thermal load in times of renewable surplus. LSTM proved to be the most accurate forecasting algorithm for this case, where the data has strong seasonality and trends. The main contribution of this work is to propose and demonstrate the effectiveness of tightly coupling thermo-electrical dispatch algorithms of HRES from the design stage, and how to effectively integrate forecast data within such algorithms

    Estimation of the nutritive value of grape pomace for ruminant using gas production technique

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    The aim of this study was to determine the chemical composition and estimation of nutritive value of white grape pomace (WGP) using in vitro gas production technique. Fermentation of WGP samples were carried out with rumen fluids obtained from three mature cannulated steers. The samples were collected from a factory in Urmia, Iran. The amount of gas production for WGP at 2, 4, 6, 8, 12, 24, 48, 72 and 96 h were measured. The results showed that the crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and non-fibrous carbohydrate (NFC) contents were 17.27, 59.5, 52.5 and 13.5%, respectively. Gas production at 24 h and potential gas production (a + b) were 30.92 and 79.89 ml, respectively. The organic matter digestibility (OMD), metabolizable energy (ME) and short chain fatty acid (SCFA) contents were 50.50%, 7.4 MJ kg-1 DM and 0.69 mmol, respectively. The net energy for lactation (NEL) content was 3.31 MJ kg-1 DM. According to the results of this study, it seems that WGP could be used as a valuable food industrial by-product in ruminant nutrition.Key words: Nutritive value, gas production, grape pomace, short chain fatty acid, metabolizable energy

    Nutritional value of raw soybeans, extruded soybeans, roasted soybeans and tallow as fat sources in early lactating dairy cows

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    Thirty multiparous Holstein cows (29.8 ± 4.01days in milk; 671.6 ± 31.47 kg of body weight) were used in a completely randomized design to compare nutritional value of four fat sources including tallow, raw soybeans, extruded soybeans and roasted soybeans for 8 weeks. Experimental diets were a control containing 27.4 % alfalfa silage, 22.5% corn silage, and 50.1% concentrate, and four diets with either tallow, raw soybean, extruded soybean, or roasted soybean added to provide 1.93% supplemental fat. Dry matter and NEL intakes were similar among treatments, while cows fed fat diets had significantly (P<0.05) high NEL intakes when compared to control with no fat. Supplemental fat, whether tallow or full fat soybeans increased milk production (1.89-2.45 kg/d; P<0.01) and FCM production (1.05-2.79; P<0.01). Milk fat yield and percentage of cows fed fat-supplemented diets were significantly (P<0.01 and P<0.05 respectively) higher than control. Between fat-supplemented diets, roasted soybean caused highest milk fat yield and extruded soybean caused lowest milk fat yield. There was no significant effect of supplemental fat on the milk protein and lactose content and yield. Feed efficiency of fat-supplemented diets was significantly (P<0.01) higher than control. Body weight, body weight change and BCS (body condition score) of cows, as well as energy balance and energy efficiency were similar between treatments. In conclusion, while there was no significant effect of fat sources on production response of cows, fat originating from heat-treated soybean help to minimize imported RUP (rumen undegradable protein) sources level as fish meal in comparison with tallow and raw soybean oil. In the Current study, there was no statistical significance among nutritional values of oil from extruded soybeans and roasted soybeans

    Predictors of Quality of Life in Transfusion-dependent Thalassemia Patients Based on the PRECEDE Model: A Structural Equation Modeling Approach

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    This study aimed to determine the predictors of Quality of Life (QoL) in Transfusion-Dependent Thalassemia (TDT) patients based on PRECEDE (Predisposing, Reinforcing and Enabling Constructs in Educational Diagnosis and Evaluation) model. This cross-sectional analytical study was performed on 389 TDT patients who were under treatment in four thalassemia centers in Tehran, Iran. Data gathering instrument consisted of three parts: socioeconomic and demographic information, the Persian version of the six standardized questionnaires for measuring some of the potential predictive factors of QoL in TDT patients based on the PRECEDE model constructs, and a researcher-made questionnaire to assess knowledge of patients about health- and QoL-promoting behaviors and enabling factors involved in health- and QoL-promoting behaviors. Using AMOS 23.0, the structural equation modeling with maximum likelihood estimation was conducted to test the proposed hypotheses. Associations of QoL with all of the PRECEDE model constructs, including anxiety-depression, self-efficacy, perceived barriers, knowledge, enabling factors, and reinforcing factors were significant (all p < 0.001). Anxiety-depression and perceived barriers were the significant negative predictors of QoL in TDT patients, whereas health-promoting lifestyle was the significant positive predictor of QoL in TDT patients. The final conceptual model of the study was adequately fit and can be applied as a framework for future educational-supportive programs aimed at improving the QoL in TDT patients. © 2019 Atlantis Press International B.V
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