bluuebunny/crossref_metadata_2025_split huggingface dataset:
System Identification for Modelling M4 Wave Energy Converter
Authors: Wang Xuefei , Liang Danni , Li Mengxiao , Stansby Peter , Zhang Long 
Published: September 2023

As one of the renewable energy resources, wave energy has the potential to be one of the major electricity generation resources in the long term. However, the industrial-scale implementation of wave energy is still at an early stage and requires deeper research and development. Currently, only several different wave energy conversion techniques such as oscillating bodies, oscillating water columns, and over-topping modules, are available. Among these energy converters, the 6-float, multi-mode, moored wave energy converter (WEC) M4 has been developed by the University of Manchester. M4 consists of a bow float, three mid floats and two stern floats with beams hinged above the outer mid floats. The mooring to the bow float includes an elastic cable from the bed to a spherical buoy and an inelastic cable linking the buoy to the bow float. The M4 converter has been modelled numerically. However, these numerical methods often require large computational resources and therefore they can only be used offline and they cannot be implemented in real-time applications. It is highly desirable to develop a computationally efficient model for the M4 system.

In this paper, system identification methods are used to model the M4 WEC system with the experimental data. First, two linear models including autoregressive with exogenous inputs (ARX) and the Box-Jenkins (BJ) model are used to build three different types of models for 6 float M4 WEC system using three different input and output variables: wave surface wave surface elevation, the mooring forces (top and bed forces) and the bow float motions (pitch, surge and heave). Further, when constructing the model of the M4 system, the impacts of both sampling rate and model orders are considered. The modelling results are compared and analysed using three selected criteria including fitting percentage, mean squared error and final prediction error. Finally, the performance of identified models are validated by wave basin experiments which covers seven major wave conditions including different wave heights and mean wave periods. Results show that both ARX and BJ models are feasible to model the M4 WEC system, with low orders and sampling rates for high short-term prediction accuracy. These models could be potentially used for real-time applications.
Comparison of Actuator Line Modelling of Tidal Power Kites with ADCP Measurements
Authors: Saravana Prabahar Nimal Sudhan , Fredriksson Sam , Broström Göran 
Published: September 2023

The potential for tidal energy to be a part of future renewable energy systems is expanding. Tidal turbines deployed in open waters or channels are effective methods to harness energy from tidal currents. Sharing similar functionality with wind turbines, horizontally mounted tidal turbines require a minimum tidal current velocity to operate effectively. The Deep Green (DG) power plant which is based on a tethered kite model aims, however, to operate efficiently in tidal current velocities as low as 1.2 m/s. The kite wing is steered in a lemniscate trajectory ( ) almost perpendicular to the tidal current. In the trajectory, the relative flow velocity through the turbine attached to the wing reaches several times the tidal current velocity, enabling efficient operation of the turbine in relatively low-velocity tidal currents. This could reduce geographical limitations in installing large-scale tidal power arrays.
In a previous project, numerical modelling of the DG was carried out in a tidal flow using Large Eddy Simulations (LES) and Actuator Line Modelling (ALM) implemented in OpenFOAM solver. ALM using momentum sources has been used in modelling wind turbines and has been validated against experimental data and observations. The ALM has been further developed in order to be able to model wings (here the kite) that move in arbitrary paths compared to horizontally mounted turbines with rotational paths. This numerical model for the DG kite in a tidal flow has, however, up to now not been validated against observations, which is beneficial before further analyses are made, e.g., optimization studies.
In this study, Acoustic Doppler Current Profiler (ADCP) observations taken in the wake of a DG are compared to the results from the numerical model under similar conditions. Comparing the numerical results directly with the observations leads to discrepancies, hence the model data is resampled in a similar way that the ADCP would measure and process data using a virtual ADCP for the model. Flow properties such as the instantaneous and time-averaged stream velocities are in turn compared for both the tidal flow without the DG and with a DG. The effect of the DG on the tidal flow is analysed using the model and the observations. After resampling the model data, the model and observations show good agreement. This suggests 1) that the DG model using ALM can be used for further analysis and 2) that whilst comparing model data with ADCP observations for studying the small-scale effects of tidal turbine wakes, care should be taken to sample the model data consistently with observations.
Preliminary performance assessment from towing tank testing of a horizontal-axis turbine
Authors: Lande-Sudall David , Tolleifsen Sondre , Gravelsæter Kjetil , Moen Harald , Bartl Jan 
Published: September 2023

Following the Norwegian government’s goal to be a ‘low emission society’ by 2050, there is a significant push to develop offshore renewable energy; principally offshore wind, but also wave and tidal stream. The MarinLab towing tank at the Western Norway University of Applied Sciences, Norway is 50 m long with a 3.0×2.2 m section and was inaugurated in 2016 as an educational and research facility, supporting local industry to achieve a low-carbon transition.
To advance knowledge of aero- or hydrodynamic interaction of future turbines for both wind and tidal stream energy, a model scale test-bed horizontal axis turbine has been developed. This turbine will enable testing of rotor diameters typically in the range of 500-600 mm. The turbine is instrumented with a torque-thrust sensor of 5 Nm/100 N capacity, custom-manufactured by Marin in the Netherlands. The turbine is speed regulated via a 4096 counts angular encoder connected to a 200 W Maxon EC-i brushless motor.
Before testing new rotor geometries, a benchmarking study is being undertaken with an existing known geometry. The benchmark rotor has diameter, D=700 mm and employs the same NACA 63418 airfoil as Mycek et al. (2014), allowing comparison. Unlike Mycek et al. (2014), the nacelle has a nominal diameter of 90 mm and length 760 mm. The size of the rotor risks exceeding the capacity of the torque sensor, such that maximum tow-speed is limited to 0.8 m/s. The benchmark blades are machined from solid aluminium in a four-axis CNC milling machine, following a method similar to Payne et al. (2017). Due to machining limitations, the minimum trailing edge thickness is specified as 0.2 mm. The final surface finish is achieved by manual polishing, and the final dimensions, quantified using a Hexagon ROMER Absolute laser scanner, are found to be within ±0.2 mm accuracy. Future blade sets will typically have a smaller diameter, allowing for 3D printing and consistency of surface finish.
A blade-element momentum model has been run with Prandtl tip and hub losses and 0° pitch (Fig. I). Lift and drag coefficients were calculated for a range of chord Reynolds numbers using XFOIL, for angles of attack between -5 to 16° and extrapolated to ±180° with Viterna’s method. Due to difficulties in estimating laminar-turbulent transition around critical Reynolds numbers, there is uncertainty in the XFOIL coefficients. At peak TSR, the chord-based Reynolds number is approximately 280k at 3/4 span. Curves for both Rec =250k (solid) and 500k (dashed) with Ncrit = 9 are presented, showing a significant drop in performance for lower Reynolds numbers, due to a collapse in Cl/Cd. Initial tests were conducted in near- zero ambient turbulence, though passive turbulence grids are available for future testing. Reasonable agreement on CT is observed when corrected for blockage according to Bahaj (2007), and further assessment will provide results on CP, tower loads and wake recovery.
Dimensioning and optimization of multi-source offshore renewable energy parks
Authors: Schaap Anton , Van der Zant Hinne 
Published: September 2023

Multi-source offshore renewable energy parks, consisting of wind, solar and wave converters, can utilize the available offshore area much more efficiently than single source wind parks. They can also produce power with a higher capacity factor than single source parks, utilizing the available grid connection more efficiently. Dimensioning and financial optimization of such parks will be driven by geographic constraints like available area, water depths, shipping lanes, exclusion zones etc., but also by the available resources of wind, solar and wave power. Another major driver in the optimization will be the electricity price. With the raising share of weather dependent renewables in the electricity mix, the electricity price will become more volatile. Therefore, an optimized design process of a multi-source park should also incorporate a pricing mechanism that can produce hourly electricity prices based on actual weather conditions. The paper will present the results of a numerical model that can integrate solar and wave power in a wind park area as well as optimize the export cable capacity. Battery storage can be added to this multi-source park to shift part of the production to hours with higher electricity prices. A case study has been performed for the planned offshore wind park TNW, North of the Dutch Waddeneilanden. Since such a multi-source park will have an expected lifetime of about 30 years, it will even reach the year 2050, in which weather dependent renewable energy will be much more dominant than today, with far stronger electricity price volatility. For the electricity price calculation, assumptions are made for the installed base of solar, wind and wave power in the whole of The Netherlands, as well as the geographic spread of this installed base over the land area and the offshore exclusive economic zone in the North Sea. This installed base is simplified by concentrating it in about ten locations divided over this area. Other necessary assumptions are the future electricity demand pattern, the future capacity of the interconnections with the surrounding countries and the capacity of the flexible load that will be available at that time (electric cars, electric heaters etc.). From literature, the cost of conventional power fueled by natural gas and/or hydrogen is derived which serves as back up power for hours with low wind, solar and wave power production. Based on all these assumptions, a pricing curve is constructed reaching from sub zero at abundant renewable supply to a maximum value at zero renewable supply. With the model, scenarios of future developments in installed wind, solar and wave power, but also in e.g. electric cars, electric heaters and other flexible loads, can be examined and the sensitivity of the optimization of the multi-source park design can be determined. The relevance of wave power can be determined from the average price per MWh that wave power can earn compared to wind and solar.
Assessment of tidal energy resources in the Strait of Magellan in southern Chile
Authors: Suarez Atias Leandro , Escauriaza Cristian , Williams Megan , Guerra Maricarmen 
Published: September 2023

The Strait of Magellan in the Chilean Patagonia (Lat: 53.5°S) connects the Atlantic and Pacific oceans through a narrow passage. Historic and current pressures from navigation, oil and coal industries combined with changes due to anthropogenic climate change and local population growth make the region both complex and relevant. A large tidal range on the Atlantic side of the strait produces very strong currents in the first and second narrows that have a significant potential for hydrokinetic energy. Maximum currents have been measured up to 5 m/s.

With the goal of performing a detailed assessment of the marine energy potential of the strait, field measurements combined with an FVCOM numerical simulations are being used to assess the tidal potential and understand the complex coastal physics of the system. Field observations were carried out in short field campaigns in 2018 and 2019 to characterize the flow in one of the channel narrows. We deployed a moored ADCP for currents and turbulence characterization, measured salinity and temperature, sea-surface elevations with pressure sensors, and made velocity transects with a vessel-mounted ADCP. These characterizations will also help to inform the role of the flow through the Strait of Magellan on the continental shelf.

The field data we collected is critical to understand the factors that control the dynamics of the flow in this section of the channel, and understand its marine energy potential. Measured velocities are being used to validate an FVCOM numerical model which will expand our spatially and temporally limited measurements, to estimate the tidal energy resources in the Magellan strait and evaluate the impacts of varying climatic conditions. The numerical model will also allow to predict the complementarity of tidal energy with other renewable resources, in the context of green hydrogen in the Strait of Magellan.

This is the first study aimed at predicting the tidal energy resources in the Strait of Magellan, combining field observations and numerical models. Future work will focus on the interactions of physical and environmental processes that can help to promote a sustainable development of marine energies in the southern part of the continent.
Hydrodynamic Response of Mocean Wave Energy Converter in Extreme Waves
Authors: Samuel John Ashlin , Venugopal Vengatesan , Retzler Christopher , Ma Qingwei 
Published: September 2023

The design of moored floating wave energy converters (WECs) must take into account extreme responses and mooring line loads in order to ensure their survival and continued wave power generation in the ocean environment. This study focuses on Mocean Energy's hinged raft WEC and aims to provide a comprehensive understanding of its hydrodynamic characteristics in survival wave conditions. To achieve this, a physical model study was conducted on a Froude scale of 1 in 50 at the FloWave Ocean Energy Research Facility, University of Edinburgh.
The experiments involved the use of NewWaves focusing of crest and trough at the model hinge location, as well as long irregular waves. Motion responses of the fore and aft bodies of the WEC were measured using a Qualisys camera, and single component load cells were used to measure the forces in the 3-point catenary mooring line. The hydrodynamic characteristics of the WEC were evaluated in terms of response amplitude operators and non-dimensional mooring line loads.
Results indicate that the fore and aft bodies of the WEC exhibit similar motion responses, except for the pitch motion. The aft body has a pitch response 2 to 3 times higher than the fore body. Concerning the moorings, the wave load on the mooring line in line with the wave direction was found to be higher than the other two mooring lines which were arranged at an angle to the wave direction.
In this paper, a brief discussion of the model set-up, parameters, test procedure, analysis of results, and discussion will be reported. The results will provide insight into the behaviour of the Mocean device in survival wave conditions and will aid with the determination of appropriate design parameters for optimal performance and survival in the ocean environment.
On spatial interpolation of ocean energy source variables: A comparative analysis
Authors: Gambarelli Leonardo , Pasta Edoardo , Giorgi Giuseppe 
Published: September 2023

In the context of wave energy systems development, the estimation of wave parameters such as significant wave height (Hs) and energy period (Te) over the entire ocean surface is of paramount importance. These information are crucial for estimating the energy harvesting potential of deployment sites, designing wave energy converters (WECs), planning optimal maintenance intervention frequency, and assessing the impact of waves on coastal communities. However, measuring Hs and the Te at every point in the ocean is impossible due to the vastness of the ocean and due to the cost and difficulties of installing and maintaining wave instrumentation buoys, since these have to survive in marine environment, which is particularly hostile. As a consequence, the amount of data is too limited and sparse in space for the practical and precise performance of these analyses. To address such data scarcity and sparsity, we analyse in this paper various spatial interpolation techniques employed to fill the spatial gaps in the wave parameter datasets. These techniques are compared in their performances in estimating the wave parameters in space given a set of known measurements in limited sampling locations. Three types of interpolators are considered: linear interpolator, spline interpolator, and radial basis functions (RBFs) interpolator. These algorithms are trained and tested on a public dataset of wave parameters from Copernicus Marine Service in an area between the coastlines of South England and North France. To simulate the available data scarcity and sparsity, only limited percentages of the ocean area are considered covered and available in the training stage (from 0.01% to 1%). The performance of each interpolator is evaluated on the remainder of the considered area in terms of Normalized Root Mean Square Error (NRMSE) and on the Normalized Mean Absolute Error (NMAE) achieved by the algorithm in reconstructing the parameters at these unsampled locations. The results of this study demonstrate the feasibility of spatial gap-filling of wave parameters, and demonstrates that the RBF algorithm outperforms the other two algorithms both in performances and, even more, in terms of robustness to different training points sampling.
The Effect of Using Autocorrection on Improving Typing Skills for Female Students with Mild Intellectual Disabilities
Authors: Alnofaie Reema , Alqahtai Saeed 
Published: September 2023

This study aimed to identify the effect of the using autocorrection to improve typing skill for students with intellectual disabilities in the transition program. The sample of the study include four students with intellectual disabilities, who enrolled in the after-school day care program, whose ages range from (21-25) years, where they taught typing skills by applying autocorrection option on the (Microsoft Word) program. Using single subject design (multiple baseline design across participants), the results showed that all students improve their typing skills on three measures: total number of correct words, accuracy, and error rates.	Keywords: autocorrection, computer printing, students with intellectual disabilities
РЕГІОНАЛЬНІ ТЕНДЕНЦІЇ І ПРІОРИТЕТИ РОЗВИТКУ АГРАРНОГО БІЗНЕСУ В УКРАЇНІ У ПЕРІОД ВІЙНИ
Authors: Юрій Лучечко  , Гордійчук Антоніна  
Published: September 2023

У статті розглянуто регіональні тенденції і пріоритети розвитку агарного бізнесу у період війни. Основною метою дослідження є виявлення регіональних тенденцій та визначення пріоритетних напрямів розвитку, обґрунтування основних заходів для прискорення розвитку аграрного бізнесу в Україні у період війни та у повоєнний період. Актуальність даного дослідження полягає в тому, що у період війни та у повоєнний час агарний бізнес матиме значні перспективи для зростання, важливо тільки виявити слабкі сторони і наслідки від війни та обґрунтувати пріоритети для подальшого зростання аграрного бізнесу, особливо у регіонах, які менше постраждали внаслідок війни. Дослідження проведено в такій логічній послідовності: визначено тенденції розвитку агарного бізнесу за регіонами України у 2022 році, формування пріоритетів розвитку аграрного бізнесу для кожної групи регіонів України в період війти та у повоєнний періоди, обґрунтування ключових заходів для прискорення розвитку агробізнесу у регіонах Західної і Центральної України для швидкої компенсації втрат аграрного сектору в решти регіонах. Масив статистичних даних охоплює наявні офіційні дані Держстату України про індекси сільськогосподарської продукції за регіонами у порівняних цінах. Об’єктом дослідження є процес розвитку агарного бізнесу у регіонах України. За результатами дослідження запропоновано заходи для стимулювання розвитку аграрного бізнесу: залучення додаткових внутрішніх і зовнішніх інвестицій для розвитку переробної ланки агарного сектору; прокладання нових транспортних і логічних маршрутів для збільшення експорту аграрної продукції; ведення переговорів про збільшення квот на експорт усіх груп аграрної продукції до країн ЄС; формування належного інституціонального середовища для виконання інвестиційних проєктів у сфері відновлювальної енергетики, випуску альтернативних видів палива на основі використання сільськогосподарської сировини і відходів; створення сприятливих економічних умов для розвитку дотичних до аграрного бізнесу секторів економіки. Результати дослідження можуть бути корисними для подальшого формування національної та регіональної політики економічного стимулювання розвитку агарного бізнесу за рахунок внутрішніх джерел.
МІЖНАРОДНИЙ ПЕРЕГОВОРНИЙ ПРОЦЕС ЯК ЗАСІБ ДИПЛОМАТІЇ
Authors: Зелінська Ольга  , Галазюк Наталія  
Published: September 2023

В даній статті розглянуто питання сутності та значення міжнародних переговорів як засобу досягнення дипломатичних домовленостей. Ціллю написання статті є вивчення специфіки та врахування впливу культурних національних особливостей на хід переговорного процесу.
Встановлено, що гостра необхідність вирішувати сучасні проблеми світової політики дипломатичними засобами внесла в переговорний процес цілий ряд суттєво нових моментів. Так в першу чергу, з збільшенням кількості глобальних проблем та їх актуальності на початку XXІ століття у світі в цілому зросло значення міжнародних переговорів як засобу вирішення міжнародних проблем дипломатичним шляяхом. Крім цього також збільшилася кількість переговорів, що ведуться у світі. Паралельно з розширенням проблематики міжнародних переговорів, до їх вирішення стала втягуватися велика кількість учасників, що можуть як безпосередньо брати участь у переговорах, так і виконувати функції експертів, перекладачів тощо. Все це є передумовою для формування системи міжнародних переговорів, орієнтовиних на спільний пошук консенсусного рішення та співробітництва.
В статті зазначено що дипломатія, являє собою систему невійськових практичних прийомів та методів, які застосовуються з врахуванням певних умов та специфіки розв’язуваних завдань. З поняттям «дипломатія» також пов’язують мистецтво ведення переговорного процесу з ціллю запобігання або вирішення конфліктних ситуацій, пошуку компромісів і консенсусних рішень, а також розвиток і поглиблення міжнародної співпраці. Варто наголосити, що дипломатія, за своєю природою, формує волю держави і намагається її донести, озвучити та узгодити з волею інших держав.
З’ясовано, що кожен народ має свої звичаї, обряди, традиції, власну культуру, та характерні особливості державного і політичного устрою. Це може суттєво впливати на ведення переговорного процесу. Національний стиль відображає найпоширеніші практики ведення переговорів, які бувають прийнятними для всіх представників країни. Проте концептуальні розходження у різних стилях ведення переговорного процесу однозначно має бути враховано тими учасниками, які працюють на результат.
Розглядаючи проблематику в українському контексті встановлено, що українська нація формувала свою ментальність дл90-х років ХХ століття під впливом різних культур, що внесло свої корективи в систему соціокультурних цінностей українського народу.