bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design Optimization of Spar Floating Wind Turbines Considering Different Control Strategies
Authors: Hegseth John Marius , Bachynski Erin E. , Martins Joaquim R. R. A. 
Published: October 2020

AbstractOne of the challenges related to the design of floating wind turbines (FWTs) is the strong interactions between the controller and the support structure, which may result in an unstable system. Several control strategies have been proposed to improve the dynamic behaviour, all of which result in trade-offs between structural loads, rotor speed variation, and blade pitch actuator use, which makes controller design a challenging task. Due to the interactions, simultaneous design of the controller and support structure should be performed to properly identify and compare different solutions. In the present work, integrated design optimization of the blade-pitch controller and support structure is performed for a 10 MW spar FWT, considering four different control strategies, to evaluate the effect of the controller on the structural design and associated costs. The introduction of velocity feedback control reduces the platform pitch response and consequently the fatigue loads in the tower, which leads to a decrease in the tower costs compared to a simple PI controller. Low-pass filtering of the nacelle velocity signal to remove the wave-frequency components results in reduced rotor speed variation, but offers only small improvements in costs, likely due to the limited wave-frequency response for the considered designs. Comparisons with nonlinear time-domain simulations show that the linearized model is able to capture trends with acceptable accuracy, but that significant overpredictions may occur for the platform pitch response.
Structural Design of a Prestressed-Concrete Spar-type floater for 10 MW wind turbines
Authors: Oh Sho , Inoue Hiroto , Takahashi Yuya 
Published: October 2020

Abstract
Prestressed concrete is gaining growing interests as an alternative to steels for the construction material for floating platforms of wind turbines due to its low material costs. Investigation of the characteristics of the concrete structure under the fluctuating loadings are necessary to ensure the structural integrity, where a reference model of both the floating concrete platform and accompanying structural design are highly useful. In this study, a reference model for prestressed-concrete spar-type floater for 10 MW wind turbines is designed together with its concrete structure. Frequency-domain analysis showed that an optimum floater diameter that gives minimum pitch angle could be found. Although the maximum pitch angles were similar for floaters with diameters of 15 m to 17 m, structural design showed that the case with the wall thickness of 0.35 m will subject to prestressed-concrete steel yielding, concrete bending cracks, and shell buckling due to water pressure. Finally the reference model is designed for a floater diameter of 16 m and wall thickness of 0.45 m.
Feasibility of machine learning algorithms for classifying damaged offshore jacket structures using SCADA data
Authors: Cevasco D , Tautz-Weinert J , Smolka U , Kolios A 
Published: October 2020

Abstract
The best practise for structural damage detection currently relies on the installation of structural health monitoring systems for the collection of dedicated high frequency measurements. Switching to the employment of the wind turbine’s SCADA (Supervisory Control and Data Acquisition) signals and their commonly recorded low frequency statistics can lead to a reduction in the number of ad-hoc monitoring sensors and quantity of data required. In this paper, aero-hydro-servo-elastic simulations for a model of a turbine are used to assess its loads and any changes in the dynamics under healthy state and a damaged configuration case study. To prove the feasibility of the damage detection through low-resolution data, the statistics of the typically recorded signals from the SCADA and the structural monitoring systems are fed into a database for training and testing of classification algorithms. The ability of the machine learning models to generalise the classification for both stochasticity and uncertainties in the environmental conditions are tested. Decision tree-based classifiers showed the capability to capture the damage for the majority of the operating conditions considered. Though the setup of the traditional SCADA sensors had to be supplemented with an additional structural health monitoring sensor, the detection of the damage has been shown feasible by referring to low-frequency statistics only.
Sequential heuristic optimisation of a real offshore wind farm site considering turbine placement and cable layout
Authors: Taylor Peter , Campos-Gaona D , Yue H , Anaya-Lara O , Jia C , Ng C 
Published: October 2020

Abstract
Competition within the energy generation industry provides an incentive for developers to build offshore wind farms with a low levelised cost of energy. Therefore, there is a need for design optimisation to reduce costs and increase energy capture. A sequential approach to optimise turbine placement and cable layout is presented, using a heuristic k-opt algorithm and mixed-integer linear programming respectively. Energy storage is considered as a means to further improve the cable selection process. A case study is carried out on the Lillgrund offshore wind farm and the resulting layout improves energy capture by 6%. Cable costs are increased but the electrical losses are reduced such that there is an overall saving over the project lifetime of 20%. Energy storage as a means to peak shave the power seen by a cable in order to reduce electrical losses or de-rate a cable section was found to be impractically large and not profitable. Future work will consider secondary revenue streams to remedy this.
Vortex interaction in the wake of a two- and three-bladed wind turbine
Authors: Bartl Jan , Hansen Thomas H. , Ludwig Kuhn W. , Mühle Franz , Sætran Lars 
Published: October 2020

Abstract
The vortex interaction in the wake behind a two- and three-bladed model scale wind turbine is investigated. The two rotors have equal solidity, and produce similar power and thrust at the design tip speed ratio. Phase-averaged quantities of the wake flow from one to four rotor diameters behind the turbines are measured in a wind tunnel. It is found that the two-bladed turbine has slower wake recovery than the three-bladed turbine, and a larger velocity deficit is produced in the far wake. The tip vortices behind the two-bladed turbine is more stable than behind the three-bladed turbine, and the vortex structures exist further downwind. In a wind farm, this could reduce the power production and increase fatigue loads for the turbines operating in the wake flow, especially during stable atmospheric conditions.
GANs enabled super-resolution reconstruction of wind field
Authors: Tran Duy Tan , Robinson Haakon , Rasheed Adil , San Omer , Tabib Mandar , Kvamsdal Trond 
Published: October 2020

Abstract
Atmospheric flows are governed by a broad variety of spatio-temporal scales, thus making real-time numerical modeling of such turbulent flows in complex terrain at high resolution computationally unmanageable. In this paper, we demonstrate a novel approach to address this issue through a combination of fast coarse scale physics based simulator and a family of advanced machine learning algorithm called the Generative Adversarial Networks. The physics-based simulator generates a coarse wind field in a real wind farm and then ESRGANs enhance the result to a much finer resolution. The method outperforms state of the art bicubic interpolation methods commonly utilized for this purpose.
Identification and prioritization of low performing wind turbines using a power curve health value approach
Authors: Martin M , Pfaffel S , te Heesen H , Rohrig K 
Published: October 2020

Abstract
Since operational managers often monitor large numbers of wind turbines (WTs), they depend on a toolset to provide them with highly condensed information to identify and prioritize low performing WTs or schedule preventive maintenance measures. Power curves are a frequently used tool to assess the performance of WTs. The power curve health value (HV) used in this work is supposed to detect power curve anomalies since small deviations in the power curve are not easy to identify. It evaluates deviations in the linear region of power curves by performing a principal component analysis. To calculate the HV, the standard deviation in direction of the second principal component of a reference data set is compared to the standard deviation of a combined data set consisting of the reference data and data of the evaluated period. This article examines the applicability of this HV for different purposes as well as its sensitivities and provides a modified HV approach to make it more robust and suitable for heterogeneous data sets. The modified HV was tested based on ENGIE’s open data wind farm and data of on- and offshore WTs from the WInD-Pool. It proved to detect anomalies in the linear region of the power curve in a reliable and sensitive manner and was also eligible to detect long term power curve degradation. Also, about 7 % of all corrective maintenance measures were preceded by high HVs with a median alarm horizon of three days. Overall, the HV proved to be a promising tool for various applications.
City-planning transformation of the functional and planning structure of districts near a railway station in the largest megalopolises (international experience)
Authors: Akhmedova E A , Kuznetsov I V 
Published: October 2020

Abstract
The article deals with the peculiarities of functioning, renovation and redevelopment of city districts proximately adjacent to the territories of railway stations and roads. Both decaying, degenerating districts and successfully developing ones are of interest. The functional, compositional and planning principles of these districts’ development with their consecutive inclusion into the full-fledged city life are revealed by analysing foreign and Russian experience. The issue of city districts near a railway station’s transformation becomes actual not only in Russia, but in many cities around the world as well. It is conditional upon the fact that to a greater extent railway infrastructure objects formerly situated outside a city begin to contact closely with the urban area in the process of urban sprawl. It is impossible not to consider their influence on planning, functional as well as architectural and stylistic solution of the infrastructure. The aim of the research is to detect the main compositional, planning and functional peculiarities and principles of the site development situated in city districts near a railway station. The following tasks were to be solved to achieve the abovementioned aim: to distinguish the examples of various countries’ cities, the structure of which includes railway infrastructure objects actively; to study briefly the district history that can influence the further urban development of the site; to analyse the chosen cities’ city-planning situations; to find out the main functions of buildings and housing as well as the urban realm elements present in districts near a railway station; to study the functionality of buildings, constructions and urban spaces that appeared in urban realm in different historic periods; to define planning and functional interconnections between the different elements of city tissue in districts near a railway station.
Analysis of profitability of production in the construction industry of the Irkutsk region
Authors: Filatov E A 
Published: October 2020

Abstract
In economic practice, many specific indicators of profitability are used. They may differ in the complexity of the calculation, the availability of necessary information, and the usefulness of the analytical conclusions process. To measure the size of profit and the amount of funds used to achieve it in the industry economy, the indicator profitability of production is used. Profitability of production is an important parameter for determining the efficiency of the economy. Profitability of production is the most general, qualitative indicator of economic efficiency of production, efficiency of functioning of companies in the industry. This indicator is very important for making current and strategic decisions. The article presents the author’s model for analyzing the profitability of production. The article reveals the influence of factors affecting the change in profitability and are more methodical approaches to its calculation (methods of factor analysis developed by Filatov E. A.). The article presents the author’s analytic, systematic statistical material for the analysis of key indicators revealing the impact on the change of profitability of the construction industry in Irkutsk region of the Russian Federation.
Compounding features of composite gypsum binders for porous composites in construction printing technologies
Authors: Chernysheva N V , Shatalova S V 
Published: October 2020

Abstract
At this stage of development of construction technologies and widespread digitalization, one of the most promising and interesting areas of the Russian and international scientific community is construction printing. The main idea of construction printing is to create a finished product or structure with a single installation. The most important task now is to master printing with porous concrete to give structures the required thermal characteristics, without which additive construction cannot fully compete with conventional technologies in the construction of wall structures. One of the promising materials in this case is foam concrete, in which the rapid fixation of the porous structure and the given shape is provided by the use of a composite gypsum binder. The paper considers the possibility of moving away from traditional composition that include active mineral additives by using Portland cements with various mineral additives. The influence of the used foaming agent on the hardening process of the gyp-sum-Portland cement system with various mineral additives was studied. This solution is designed to simplify the technology, make it more attractive for small and medium-sized businesses, increase the compatibility of the binder with foaming agents, as well as its activity to ensure high mechanical performance of foam concrete.
Accounting policy of construction companies in accordance with International Financial Reporting Standards
Authors: Derzayeva G G 
Published: October 2020

Abstract
This paper examines the practical experience of construction companies in terms of their disclosure of information about significant elements of accounting policy in the notes to their financial statements prepared in accordance with International Financial Reporting Standards. The aim of the study is to identify the main problematic issues that arise in construction companies when preparing accounting policies in accordance with International Financial Reporting Standards and find ways to solve them. Using such methods as analysis and synthesis, comparison, logical and systematic approaches, the author identifies the main problems that occur in construction companies when drafting accounting policy, as well as offers solutions to them. As a result of the research, the paper compares the practice of forming accounting policy by leading construction companies, identifies the main problematic aspects and suggests ways to solve them. The article concludes on the uniformity of approaches to disclosure of information about significant elements of accounting policy, proves the identity of most of the problematic aspects that arise in the formation of accounting policy in accordance with International Financial Reporting Standards by construction companies, and substantiates the analogy of ways to solve them.
Methods of risk minimization in investment and construction projects
Authors: Sukhorukova I V , Maksimov D A , Fomin G P 
Published: October 2020

Abstract
The paper puts forward a hypothesis about the possible integration of risk assessment methods in order to minimize them in investment and construction projects, for that the problems of risk minimization in the management and implementation of construction projects are considered. A critical review of existing methods of risk analysis is carried out and a method of risk minimization is proposed based on the creation of a “Construction risk Informatoria” and methods for optimizing the reallocation of resources according to the minimum time criterion, which determines the risk of lost profits. The example of the use of risk minimization methods in the optimization procedure for network models of low-rise building construction is given, and the composition of the application of mathematical methods and models that contribute to increasing the economic effect in this area is described. As a result, effective recommendations were developed in the form of tools for monitoring the dynamics of construction work to prevent risk situations.
Plasters with wood processing waste additives
Authors: Drozdyuk T A , Sokolova Yu V , Makhova T A 
Published: October 2020

Abstract
The paper assesses the influence of additives based on wood processing industry waste on the physical and mechanical properties of plasters. As additives to the plaster, the bark and sawdust of Scots pine were used, previously crushed and purified from extractive and easily hydrolysable substances. Extraction of extractive substances from wood processing waste was performed by hot water extraction. The content of additives was in the range from 1.5 to 6 % by weight of cement. The average density, compressive strength, flexural tensile strength, water absorption, and thermal conductivity were monitored for the obtained samples of plasters. As a result of the carried out experiments, it was found that the quantitative increase of the additive in the mixture reduces the density of the mortar, water absorption increases slightly, the coefficient of thermal conductivity and the tensile strength during bending decreases. The compressive strength increases with the addition of sawdust 1.5 %, in other cases it decreases with the increase in the amount of the additive. It is shown that mortars with the addition of fine wood processing waste can be used as plasters with reduced thermal conductivity for interior work.
Properties of phosphogypsum as technogenic soil
Authors: Saenko Yu V , Shiranov A M , Nevzorov A L 
Published: October 2020

Abstract
Phosphogypsum (CaSO4·2H2O) is heavy tonnage waste generated by binding calcium in the process of sulfuric acid decomposition of phosphate raw materials when obtaining wet-process phosphoric acid in the production of phosphate fertilizers. In appearance, it is solid fine-crystalline substance of white or gray color with inclusions of large aggregates. The paper presents the results of laboratory studies of more than 390 samples of phosphogypsum neutralized with construction lime. The deformation and strength properties as well as the water permeability were determined on specially prepared samples with the relative compaction of 0.95, 0.90 and 0.80 by methods used in engineering and geological surveys. While the angle of internal friction, the cohesion and the coefficient of permeability of the phosphogypsum have the values typical for fine or silty sands, the compressibility characteristics are significantly worse due to the solubility of the particles. Phosphogypsum is characterized by subsidence and suffusion settling, which are proper for carbonate rocks (dolomite, limestone). The use of the phosphogypsum as ground is possible for subbase of roads with low traffic intensity with a gravel pavement, for dams at industrial solid waste storage facilities, as well as for engineering reclamation of those storage facilities, but only if implementing water protection measures.
The newly laboratory equipment for exploring of freezing and thawing soils
Authors: Korshunov A A , Churkin S V , Nevzorov A L 
Published: October 2020

Abstract
Frost heaving is a challenge for geotechnical engineers in cold climate. Frost heave depends on two factors: the freezing rate and the velocity of water migration from unfrozen to frozen soil. The article deals with the existing apparatus for exploring frost heave which are systematized according to their purpose (measured parameters), design features and experimental conditions. The authors proposed the ways for improving laboratory equipment and presented newly developed apparatus for studying both the frost heaving and its consequences. The article presents apparatuses that allow controlling the freezing rate of soils by step-by-step movement of the freezing cell along the sample and providing even movement of the frost front in center and edges of the soil sample. Control of water migration to the frost front is carried out by making a vacuum in a base plate or using a porous item with a given water permeability. To study the impact of cyclic freezing-thawing on water permeability both along and across the cryogenic texture the authors developed a special apparatus in which horizontal permeability test is performed through the perforated double walls of multi-ring cell, vertical test-through bottom and top porous discs.
A novel approach for coverings transformation to define a robot workspace
Authors: Rybak L A , Behera L , Averbukh M A , Sapryka A V 
Published: October 2020

Abstract
The article discusses the application of optimization algorithms to solve the problem of determining the workspace of robots. The development of a numerical method for approximating the set of solutions of a system of nonlinear inequalities that describe the restrictions on the geometric parameters of a robot based on the concept of non-uniform coverings is considered. An approach is proposed that allows you to reduce the number of boxes and numbers describing each of the boxes. Reducing the number of boxes is achieved by combining the boundary boxes of the covering set and the area between them along one of the axes. The dimensions along the other axes are equal for all boxes, which allows them to be described by one number. The transition to the integer space is described. Thus, converting non-uniform covering sets to a partially ordered set of integers reduces computational complexity. An algorithm for converting boxes of a covering set is presented. The approach has been tested for a 3-RPS robot.
Effects of Thermal Diffusivity Analysis after Irradiation
Authors: Willie Ahli K. D. , Zhao Hongtao , Svetlana Teplinskaya 
Published: October 2020

Abstract
The diffusion calculation gives a vivid understanding as to what happens in the SiC-cladded material. Molecular Dynamics (MD) and Molecular Statics are being employed to study the diffusion coefficient phenomena. The MD simulations in this study are been built on the ZBL potential. In this work we initially applied the MD simulation for minimization within the temperature range of 1000-3000 K. Then the MOX fuel is then used to perform assessment of radiation damage by ions at burnup temperatures as well. Various chemical states are developed depending on the condition of the fuel. Within the fuel lattice the O atoms break bonds with the U-Pu atoms at higher temperature. The very short diffusion lengths mechanisms results were obtained measured for uranium atom over the course of this 300ps simulation.