bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studying the effect of the number of laser pulses on the structure, morphology, and optical properties for a thin film of GO-Ag nanocomposites
Authors: Al-Mousawi Mousa Muhammad Ali , Al-Nafiey Amer , Al-Dahesh Ghaleb 
Published: September 2021

Abstract
In this paper, studying the effect of the different numbers of laser pulses on graphene oxide -silver nanoparticles (GO-Ag NPs) thin film prepared by the pulse laser deposition (PLD) on silicon and quartz substrates. The laser using in PLD is an ND-YAG laser with a wavelength (1064 nm)m with a repetition rate of 6 Hz with a laser pulse duration (9 ns). Atomic force microscopy AFM and XRD using for analysis of the thin film, the results showed the possibility of preparing thin films with different sizes of granule and crystalline sizes on the nanoscale. Also, show that the granular size and crystal size of the nanoparticles decrease with the increase in the number of laser pulses with the constant energy. Moreover, the optical properties measurements showed that the absorbance and absorption coefficient increase with the increase in the number of pulses when the energy is constant, while the energy gap decreases with increasing the number of pulses These results were promises to producing the thin film for Graphene oxide-silver nanocomposites for different applications compatible with it.
A new green method for indirect determination of ferric ions in biological samples using Ascorbic acid as reducing agent via the development of CFIA system
Authors: Qassim Bushra B. , Hamed Luma L. 
Published: September 2021

Abstract
A simple, sensitive, automated and environmentally friendly FI/MZ technique was suggested for the indirect determination of iron (III) as ferric chloride in bulk and biological. These method involve the reduction of Fe (III) to Fe (II) using ascorbic acid as reducing agent, the reduced ion was reacted with 1,10- phenanthroline as a selective organic reagent to form red-orange complex, measured at λ=510 nm. The complexation ratio between matel ion with ligand was 1:3 ratio (M: L). The colored product obeyed Beer’s Law with linear ranges 1-30 and 8-75 μg/mL with detection limits 1.02, 0.28 μg/mL for batch and FIA/MZ methods, respectively. The rate of sampling was 54 sample/h, the %RSD less than 2% and the recovery was about 99%. The developed technique was simply and low cost with high throughput, it provides the use of an aqueous medium as carrier of chemicals in flow system that is nontoxic and causes no pollution, thereby belonging to green chemistry. The proposed procedure can be successfully applied to estimate the content of Iron (III) in biological samples. The results of estimation are satisfactory as compared with those given by a reference method, showed the new method to be accurate and precise at the 95% confidence level.
Imaging of Surface Plasmon Resonance for Nano Material of Different Shapes
Authors: Mohammed S.H. , Shanan N.S. 
Published: September 2021

Abstract
The studies of Surface Plasmon Resonance SPR have focused on novel materials (gold and silver ). In this paper, four kinds of samples have been prepared also the system of plasmonic imaging with objective lens to excite the SPR our samples. The hot spot images for our different samples proved that the blue wavelength (405nm) can be excite the SPRs better than the green wavelength (532nm) for silver samples and the green wavelength can be excite the SPRs better than the blue wavelength for gold samples, also the increasing in consternation of AgNWs due to increasing in width of Gaussian hot spot.
Preparing and Studying the Combination of ZnS/rGO Nano Composite by Laser Ablation Method
Authors: Jawad Wasan H. , Jader Mohammed J. 
Published: September 2021

Abstract
The mixed compound zinc sulfide (ZnS/rGO) nanoparticles were synthesized by the physical method laser ablation From there, the crystal structure and crystallite size of X-ray diffraction (XRD) particles were determined (D =8.35nm). The optical properties have also been studied by the visible ultraviolet absorption spectrum. Where the graphen oxide was prepared by a hummer method, after mixing it with zinc sulfide, and it was formed as a Nano composite by using the Neodymium-Yak laser (1064 nm) with the pulsed laser energy of 800 mJ and 600 pulse at a frequency of 6 Hertz in room temperature, thus generating an ionic plasma that contributed to the formation of nanoparticles. Several measurements were made on the sample, such as FTIR, to find out the constituents of the Nano composite and Energy gap is 4.942ev to calculate from UV-Visible by Tuac plot, also, determine the averge Green size (25.2nm) from XRD by using the Scherer equation, and to take SEM tests of the compound.
Low-frequency dynamic wake meandering: comparison of FAST.Farm and DIWA software tools
Authors: Rivera-Arreba I , Eliassen L , Bachynski E E , Panjwani B 
Published: September 2021

Abstract
Most of the global dynamic response models used today for the design of wind turbines are based on the aero-hydro-servo-elastic analysis of one single turbine. However, research on bottom- fixed offshore wind turbines has shown that interactions among turbines in a farm influence both the power production and the structural loading. Furthermore, floating wind turbines (FWTs) are sensitive to low-frequency variations, and therefore to wake meandering perturbations. In the current work, we use the Dynamic Wake Meandering (DWM) model as implemented in DIWA and FAST.Farm, to study the low-frequency content of the meandering at a target turbine placed 8 diameters downstream. At frequencies in the range of the natural frequencies of rigid body motions of semisubmersible floaters, the two models yield different results. These differences are seen for every wind speed and wind turbine model, even though they decrease as the wind speed increases. The observed differences may affect low-frequency motions and consequently mooring system design.
Data driven case study of a wind turbine main-bearing failure
Authors: Mello Elisha de , Kampolis Georgios , Hart Edward , Hickey Daryl , Dinwoodie Iain , Carroll James , Dwyer-Joyce Rob , Boateng Ampea 
Published: September 2021

Abstract
This paper presents a data driven case study of two outer-race spalling faults in double-row spherical roller main-bearings, with the purpose of identifying key features and relevant measurements associated with this failure mode in wind turbine main-bearings. Supervisory data is analysed for one fault case and vibration data for the other. The aim of this work is to inform practitioners and assist in improving fault detection systems for this component.
Simplified wake modelling for wind farm load prediction
Authors: Vaal Jacobus B de , Muskulus Michael 
Published: September 2021

Abstract
This paper presents a simple numerical wind farm model, where pragmatic choices are made in the modelling of underlying physical processes, with the aim of making useful power production and wind turbine load estimates. The numerical model decomposes the wind farm, inspired by the approach of the dynamic wake meandering model (DWM), into simple sub-models for a single wake deficit (1D Gaussian), wake meandering (statistical), and wake added turbulence (eddy viscosity based). Particular attention is given to selecting a momentum conserving wake summation method, because of its critical role in coupling the influence of individual wakes. Results are presented to illustrate the influence that wake summation methods have on equilibrium velocity and power production in a row of turbines, for different inter-turbine spacing and inflow velocities. Comparisons against published data from the Lillgrund wind farm illustrate that the suggested modelling approach reproduces important trends observed in the field data.
Evaluation of a low-fidelity hydrodynamic modelling approach for a floating wind turbine mounted on an enhanced spar
Authors: González Guido Grassi , Urbán Albert Meseguer , Horcas Sergio González , Roqueta Laura Voltá I , Blanco Sergio Hernández 
Published: September 2021

Abstract
The present work revolves around the numerical simulation of floating offshore wind turbines, a promising technology for energy harnessing in deep water conditions. A reference 10MW wind turbine is studied, mounted on a commercial enhanced spar buoy, referred to as the WIND-bos platform. The focus is put on the hydrodynamic modeling. In particular, the Morison equation is used, accounting for a fixed set of coefficients. Those coefficients are initially estimated based on the literature, and subsequently calibrated through the comparison with experimental results on a scaled geometry. This allows to assess the modeling capabilities of the Morison approach, together with its challenges and limitations. Larger discrepancies between the numerical model and the experiments were assumed to be related to the geometrical particularities of the floating platform. In particular, the studied structure accounts for both large and slender members, potentially limiting the applicability of the method. It is shown that the deviations could be attributed to the frequency-variation of parameters such as the added mass, the radiation damping and viscous damping. Therefore, it is concluded that the agreement between the numerical model and the experiments could be improved by re-calibrating the coefficients for each of the studied sea states.
A computer tool for optimisation and simulation of marine operations for offshore wind farm installation
Authors: Halvorsen-Weare Elin Espeland , Fonn Eivind , Johannessen Kjetil , Kisialiou Yauheni , Nonås Lars Magne , Rialland Agathe , Thun Kristian 
Published: September 2021

Abstract
The installation process of offshore wind farms is complex and requires a high level of coordination, agile scheduling and systematic methods. High risks and costs are involved and especially weather conditions have an impact on the marine operations. A computer tool for optimisation and simulation of marine operations has been developed in close cooperation with a large actor in the offshore wind industry. The tool has a web-based user interface and an optimisation engine that is based on a version of a genetic algorithm and uses an agent-based simulation process to evaluate installation schedules with respect to weather risks, time and costs. The objective is to provide decision support for the early phase planning of wind farm installation by offering an efficient method for estimation of cost and time for future projects.
Comparison of concrete and steel semi-submersible floaters for 10MW wind turbines
Authors: Oh Sho 
Published: September 2021

Abstract
Prestressed concrete floaters are gaining growing interest for floating wind turbines, while different material properties can affect the characteristics of floater motions and the range of suitable floater geometries. In this study, a basic geometry of a semi-submersible floater for 10MW is designed, based on which sensitivity study of the material property on floater design is conducted. It was found that minimum floater pitch angles achieved by selecting the optimum floater geometries were similar for the three types of material, while larger values of geometrical variables were required for concrete floaters than for steel floaters for a floater pitch limitation. If larger wall thickness was to be required for concrete structures due to, for example, corrosion protection and crack limitation, generally larger side column width and lower hull length were required for concrete floaters. As the sensitivity of pitch angle to the wall thickness was more affected by wind excitation than wave excitation for normal concrete, it is indicated that the design space for the length of hull can be widened by combining the design with the wind turbine controller methods in the treatment of the maximum thrust force. Lightweight concrete had advantages over normal concrete in the lower center of gravity. The raw material cost of lightweight concrete was higher than normal concrete but significantly lower than steel floaters.
Gradient-based optimization of a 15 MW wind turbine spar floater
Authors: Pollini Nicolò , Pegalajar-Jurado Antonio , Dou Suguang , Bredmose Henrik , Stolpe Mathias 
Published: September 2021

Abstract
We discuss the optimization-based conceptual design of support structures and mooring system for floating wind turbines. A four degree-of-freedom frequency-domain model is used for the dynamic response of a spar floating wind turbine subjected to wind and wave loads. The framework allows for design optimization involving the geometrical properties of the floater and the mooring system and inclusion of long realizations of multiple load cases in the analysis. The adopted optimization approach adopted relies on analytical design sensitivities of the governing frequency-domain equations and of the design requirements. This ensures that modern gradient-based optimization algorithms can effectively be used to solve the design problem at hand. The optimization approach is applied to the design of the spar-buoy floater and its mooring system for the IEA 15 MW reference wind turbine. A post-processing approach for identifying discrete designs from predefined catalogues is also presented. The post-processing allows to transform continuous design solutions into practical ones that can be used in subsequent analyses with time domain response models for the full validation of the design solutions obtained. The numerical results highlight the capability of the approach discussed herein to provide discrete optimized designs for given design constraints and loads in few minutes requiring modest computational resources and time.
Uncertainties assessment in real-time hybrid model for ocean basin testing of a floating offshore wind turbine
Authors: Somoano Miguel , Battistella Tommaso , Fernández-Ruano Sergio , Guanche Raúl 
Published: September 2021

Abstract
This work analyses the accuracy of large-scale experimental testing procedure in ocean basin facility involving real-time hybrid model testing (ReaTHM) techniques. The analysis is based on a scaled concept for a 15MW floating offshore wind turbine (FOWT) supported by a concrete semi-submersible platform (ActiveFloat) developed within the framework of the project COREWIND. The real-time hybrid model considered includes a multi-fan system located at the aero-rotor interface, which permits to generate the aerodynamic loads, reducing the limitations typically given by scaled problems. In order to assess the uncertainties in the hardware in the loop (HIL) implementation, firstly we define the quantities of interest to be evaluated from all the possible sources liable to inaccuracy identified. Then, we quantify the systematic and random discrepancies of the selected mooring, platform and HIL parameters. Finally, we propagate the previously quantified errors, running simulations in OpenFAST under extremal and severe environmental load cases in Gran Canaria Island (Spain) site. Comparing the platform response and mooring tensions of these uncertainty propagations with the ones of the unperturbed simulation as a baseline case, we analyse the effect of each representative parameter. Thus, the reliability of the results in ocean basin testing is numerically assessed, depending on the design load case.
A nested multi-scale model for assessing urban wind conditions : Comparison of Large Eddy Simulation versus RANS turbulence models when operating at the finest scale of the nesting.
Authors: Tabib Mandar V , Midtbø Knut Helge , Rasheed Adil , Kvamsdal Trond , Skaslien Tor 
Published: September 2021

Abstract
Good understanding of micro-scale urban-wind phenomena is needed for optimizing power generation capabilities of building-integrated wind turbines and for safety of futuristic urban transport involving drones. The current work involves development of a multiscale methodology for obtaining wind fields in an urban landscape. The multi-scale methodology involves coupling three models operating on different scales namely an operational meso-scale numerical weather prediction model HARMONIE, a micro-scale model that captures terrain- induced wind influence and a super-micro scale Computational Fluid Dynamics model using large eddy simulation and RANS model to capture the building-induced wind flow. Here, we present a comparison of the wind velocity predicted by two different turbulence models (LES and RANS) that are operating at the finest scale with the measured experiment data for a realistic case of flow in vicinity of the Oslo university hospital. The reasons behind the observed better prediction of LES model are outlined, and use of such models is advocated to improve accuracy.
LES, multi-scale, wind, urban climate, drones, wind energy
A Numerical Investigation of the Geometric Characteristics of Floating Wind Turbine Wakes under Axial and Yawed Rotor Conditions
Authors: Valentin J. , Sant T. 
Published: September 2021

Abstract
The physics of wind turbine wakes on fixed foundations have been extensively studied through numerical modelling and measurements over the recent decades. While research initiatives in the field of floating wind turbines have increased significantly, various aspects characterising floating turbine wakes are still not well understood. This paper applies a free-wake vortex model to derive the geometric characteristics of the wake of a surging rotor under axial and yawed rotor conditions. The study examines the influence of platform motion on the wake boundaries and centreline up to four rotor diameters downstream. It is shown that floating turbine wakes experience a higher degree of perturbation as compared to those of fixed turbines. This is highly dependent on the sea state and suggests the need to develop new analytical wake models for the wind industry that are able to account the effect of platform motion on wake behaviour.
Magnetic force enhanced atmospheric plasma polishing ability to improve surface roughness of copper base materials
Authors: Chen H L , Syue S H , Chen Y L , Chen Y J 
Published: September 2021

Abstract
The global demand for portable miniature products has increased, which has driven the improvement of micro-component technology to meet the precision requirements of miniaturization of product sizes and higher precision of products. As the requirements for the assembly accuracy of precision components and the high quality on the surface treatment of materials, the current precision polishing is also facing a technical bottleneck. Many polishing technologies have been developed, atmospheric plasma polishing is a new polishing technology, which is applied to the precision components of the optoelectronic industry. How to improve the polishing efficiency of atmospheric plasma has become a new research topic. In this study, a non-traditional surface treatment method which low-temperature atmospheric plasma is used to precision polish the copper-based material, and added magnetic force on the surface of the copper-based material, in order to enhanced atmospheric plasma polishing ability to improve surface roughness of copper base materials. The low-temperature atmospheric plasma jet has been used; the power of plasma is 50Wand nitrogen (N2) as reaction gas. The different scanning speed of stages is 2, 5, 10, 15 and 20 mm/s, respectively. The processing time is 10min. A copper foil substrate is as select material. Observe the surface roughness variation of the copper foil substrate treated by atmospheric plasma. The results shown that when the copper foil substrate is treated with low-temperature atmospheric plasma and no magnetic force on the surface, when the scanning speed of the stage is 2 mm/min, the improvement rate of surface roughness is about 17.6%; when the scanning speed of the stage is 20 mm/min, the surface roughness improvement rate is about 5.5%. When the magnetic force on the surface is about 188 mT, the improvement rate of surface roughness is about 30.8% when the scanning speed of the stage is 2 mm/min, and the improvement rate of surface roughness is about 12.5 % when the scanning speed of the stage is 20 mm/min. From the above results, it is known that applying magnetic force on the surface of the work-piece can indeed increase and improve the polishing ability of the low-temperature atmospheric plasma.
Study on shape memory effect of hot deep-drawn NI-TI shape memory alloy sheet part
Authors: Fann K J , Chang C H 
Published: September 2021

Abstract
This study investigates the properties of Ni-rich Ni-Ti shape memory alloy sheet parts during and after deep drawing process at an elevated temperature, which is under a plane tensile-compressive stress state. According to the results, the sheet metal shows superelasticity and ductility at 500°C, 550°C, and 600°C. In the hot deep drawing process, the working parameters affect the result. The higher the forming temperature and the longer the holding time at the bottom dead center of the punch or the longer the ageing shape memory treatment, the greater the height of the drawn part and the lesser the springback. The results of the subsequent free recovery experiment show that the deep drawn sheet part without ageing treatment still possesses the shape memory effect. It also shows in the further constraint recovery experiment that in a wide temperature span the deep drawn sheet part possesses a different recovery load when reacting to the phase transformation of the shape memory alloy. Furthermore, the higher the forming temperature and the shorter the ageing treatment, the greater the part recovery load.
Characteristic analysis of rotating ultrasonic machining applied in zirconia grinding
Authors: Chen T H , Lee J N , Tsai M H , Fu S W , Wu Y C 
Published: September 2021

Abstract
This research uses rotary ultrasonic grinding technology to grind zirconia (ZrO2) ceramic. The purpose is the optimization of processing parameters for rough and fine grinding. According to Taguchi method, optimized processing parameters will be available to find and successfully verified. The objective function of rough grinding is the material removal rate (MRR), and a maximum is expected. The processing parameters can be spindle speed, ultrasonic power, feedrate, and cutting depth. The best MRR is 192mm3/s in Taguchi’s experiment, and the optimized MRR is 2.14mm3/s, which can be increased by 1.11 times.
Moreover, the objective function of fine grinding is surface roughness (Ra), which needs to find a minimum value. The control factors are spindle speed, ultrasonic power, feedrate, and the number of times of grinding. In the Taguchi experiment, the minimum roughness predicted by the fine grinding is Ra0.16, but the roughness is obtained Ra0.2 by the verification experiment. It may be that the effects of the factors are not completely independent, and there are interactions between them. The predicted value will not be completely correct via the superposition of each factor effect. It can also be found that the independence of the fine grinding speed, ultrasonic power and feed factor is not strong enough for the variation analysis. It affects the results of the prediction and confirmation experiment.