bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymorphic uncertainty in met-ocean conditions and the influence on fatigue loads
Authors: Hübler Clemens , Müller Franziska , Rolfes Raimund 
Published: October 2020

Abstract
An accurate numerical simulation of the structural lifetime of offshore wind turbines is a challenging task due to several reasons. One of them is the uncertainty of met-ocean conditions acting on a turbine, e.g. wind and waves. This uncertainty can be divided into two kinds of uncertainty: aleatory and epistemic uncertainty. If both types of uncertainty occur, this is called polymorphic uncertainty. According to the state of the art, for met-ocean conditions, mainly aleatory uncertainty is considered or both types of uncertainty are modelled using a single probability density function. This leads to a simplification of the actual uncertainty, whose effect on the lifetime estimation has not been analysed so far. In that sense, in this work, the influence of various uncertainty models for met-ocean conditions on long-term damage equivalent loads (DELs) - representing the wind turbine fatigue lifetime - is investigated. For this purpose, different uncertainty models for met-ocean conditions are derived using real measurement data. Not only purely probabilistic models are applied, but imprecise probabilities - here interval random variables - as well. It is shown that the uncertainty models have a considerable influence on the fatigue life of offshore wind turbines. Especially, the large fatigue load intervals, which are determined, clarify the importance of a well-founded decisions regarding uncertainty modelling of met-ocean conditions.
The dynamic response of offshore wind turbines and their sensitivity to wind field models
Authors: Myrtvedt Maylinn Haaskjold , Nybø Astrid , Nielsen Finn Gunnar 
Published: October 2020

Abstract
As the rotor diameter of offshore wind turbines increases, an improved understanding of the structure of the turbulent wind field approaching the rotor is important. Present standards for computing wind loads are resting upon assumptions of neutral atmospheric conditions and a simplistic formulation of the coherence of the turbulence. In the present work, various formulations of the wind field are applied and the dynamic responses of a bottom fixed and a floating wind turbine are computed to investigate the sensitivity to the formulation of the wind field. Focus is on wind situations with above average turbulence intensity as these are expected to have a significant contribution to fatigue damage of the structure. It is observed that choice of wind spectrum, coherence formulation as well as assumptions related to atmospheric stability conditions significantly influences the dynamic loads in tower bending moment, yaw moment and blade flap moment. The differences are significant in particular in the low frequency range. This implies that in particular floaters are sensitive to the formulation of the wind field.
Evaluation of Gaussian wake models under different atmospheric stability conditions: Comparison with large eddy simulation results
Authors: Krutova Maria , Paskyabi Mostafa Bakhoday , Nielsen Finn Gunnar , Reuder Joachim 
Published: October 2020

Abstract
The calculation of the velocity deficit in the wake of individual wind turbines is a fundamental part of the wind farm analysis. A good approximation of the wake deficit behind a single wind turbine will improve the power estimation for downwind turbines. Large-eddy simulation (LES) is a research tool widely used in studying the velocity deficit and turbulence intensity in the wake. However, the computational cost of the LES prevents its application in wind farm performance analysis and control. Existing analytical wake models provide a fast estimation of the velocity deficit and the wake expansion rate downstream from the rotor. The Gaussian wake models use a Gaussian distribution to improve the prediction of the wake velocity deficit. With the number of analytical models available, an extensive evaluation of their performance under different flow parameters is needed. In this work, we simulate a wake of a single wind turbine using the LES code PALM (Parallelized LES Model) combined with an actuator disc model with rotation. We compare the computed flow field with the predictions made by Gaussian models and fit their parameters to obtain the best possible fit for the wake field data as computed by LES.
Predictive Analysis of Machine Learning Schemes in Forecasting Offshore Wind Speed
Authors: Bakhoday-Paskyabi Mostafa 
Published: October 2020

Abstract
High variability of wind in the farm areas causes a drastic instability in the energy markets. Therefore, precise forecast of wind speed plays a key role in the optimal prediction of offshore wind power. In this study, we apply two deep learning models, i.e. Long Short-Term Memory (LSTM) and Nonlinear Autoregressive EXogenous input (NARX), for predicting wind speed over long-range of dependencies. We use a four-month-long wind speed/direction, air temperature, and atmospheric pressure time series (all recorded at 10 m height) from a meteorological mast (Vigra station) in the close vicinity of the Havsul-I offshore area near Ålesund, Norway. While both predictive methods could efficiently predict the wind speed, the LSTM with update generally outperforms the NARX. The NARX suffers from vanishing gradient issue and its performance declines by abrupt variability inherited in the input data during training phase. It is observed that this sensitivity will significantly decrease by integrating, for example, the wind direction at low frequencies in the learning process. Generally, the results showed that the predictive models are robust and accurate in short-term and somewhat long-term forecasting of wind.
Splipy: B-Spline and NURBS Modelling in Python
Authors: Johannessen K. A. , Fonn E. 
Published: October 2020

Abstract
Splipy is a pure Python library for the creation, evaluation and manipulation of B-spline and NURBS geometries. It supports n-variate splines of any dimension, but emphasis is placed on the use of curves, surfaces and volumes. The library is designed primarily for analysis use, and therefore allows fine-grained control over many aspects which cannot be achieved with conventional CAD tools. It is packaged and distributed through Python Package Index: PyPi which gives easy installation.
Modern methods of intensification of heat exchange processes in plate apparatuses
Authors: Savvin N Yu , Kushchev L A , Alifanova A I 
Published: October 2020

Abstract
The heat supply system of the Russian Federation is characterized by significant wear and tear of equipment: heating networks and boilers. At the same time, an important element of heat supply systems equipment is heat exchangers of various designs, which are used in boilers, IHP, thermal power plants, and nuclear power plants. Various heat exchange equipment used in modern heat power engineering is considered. It is established that the use of plate heat exchangers is a more appropriate engineering solution than shell-and-tube heat exchangers, due to economic factors and operational advantages. The method of intensification of heat transfer of the heated liquid by means of technological depressions of spherical shape located according to the linear law is considered.
Features of mathematical formulation and solution of the problem of optimal division of funds in the construction business
Authors: Chernyaev A P , Meerson A Yu , Sukhorukova I V , Fomin G P 
Published: October 2020

Abstract
The paper considers a microeconomic model of the construction business economy, assuming that it is a stable object in a crisis. The paper presents the distinctive features of the microeconomic formulation of the problem of finding a method for optimal separation of construction materials into consumed and accumulated parts. This area is constantly paid attention to and described in the media, sometimes with much unexpected outcome for investors. It is quite natural that consumption is optimized, just as in macroeconomics, but not in its pure form. The integral discounted utility of consumption is maximized. The communication equation in this paper differs from the similar macroeconomic equation, as the construction business exists and survives even in crisis conditions not in the same way as it does in social environments.
One of the approaches to the concrete strength mathematical model
Authors: Nikonorov V M , Nikonorov V V 
Published: October 2020

Abstract
The importance of concrete as a structural material is undeniable. The key indicator of concrete as a construction material is strength. Creating and solving a concrete strength mathematical model will allow optimizing raw material costs, increasing the financial result of concrete production, and managing the concrete strength at the stage of its production. The authors reviewed existing concrete strength mathematical models. In the considered models, the concrete strength was influenced by various factors – water-cement ratio, C3S hardness, etc. The authors used the kinetic theory of solid destruction as the basis for their mathematical model of concrete strength. The process of destruction of the sample is considered without deformation. Applying the concept of strained and broken bonds, the authors constructed and solved a concrete strength mathematical model. The main parameters of the model are the speed formation coefficient of the stressed bonds and the speed formation coefficient of destroyed bonds. The model allows estimating the time required for sample destruction at a given load. This is a non-trivial conclusion.
Innovative structural and technological developments of pile foundation engineering
Authors: Kocherzhenko Vladimir , Suleymanova Lyudmila , Kolesnikov Maksim 
Published: October 2020

Abstract
The paper considers innovative structural and technological solutions for precast piles, which significantly increase their load-bearing capacity: a transformable pile and a pile with “pockets” (recesses) on the side surface for use in loose soils. In the first case, in the manufacture of precast reinforced concrete piles in the center they set plastic cone-shaped cruciform brake detail with length 0.75 of the pile length, in which after driving the piles destructive non-explosive substance is poured, that increasing in volume in 2-3 times, transforms prismatic pile into a pyramid one. In the second case, when making precast concrete piles, they provide for the arrangement along the side faces of “pockets” (recesses). The liquid hardening compound located in the “pockets” penetrates into the soil of the pile during the driving process and secures it, which significantly increases the lateral friction force of the pile and its load-bearing capacity and reduces the energy of the pile sinking. The considered design and technological solutions allow reducing the energy of pile driving, while increasing their load-bearing capacity.
Method for predicting the remaining life of the ball mill support axle based on changes in the design stresses of the external surface of the axle
Authors: Bondarenko J A , Duyun T A , Bestuzheva O V 
Published: October 2020

Abstract
The article considers a method for predicting the residual life of the ball mill support axle based on changes in the calculated stresses of the external surface of the axle. The main terms of forecasting the remaining life of large-sized equipment are considered. The task is set and controlled parameters are selected for the development of the methodology. An algorithm for implementing a method for predicting the residual life of the ball mill support axle based on external surface stresses is presented. A method has been developed for predicting the residual life of ball mill support axles based on changes in the design stresses of the external surface of the trunnion, which allows you to set parameters that affect the duration of the residual life without stopping the mill and to adequately calculate the residual life of the trunnion, including from the start of operation of the mill. The homogeneity of the obtained data is estimated. The parameters of the stress distribution of the external surface of the trunnion are determined, indicating that the obtained distribution corresponds to the theoretical Weibull distribution and the validity of using this method for predicting the resource of the ball mill support trunnion. The values of the guaranteed residual life of the ball mill trunnion are calculated according to the developed method. The analytical dependence of the residual life of the ball mill trunnion on the equivalent stresses occurring on the external surface of the trunnion is given.
Design process of executive elements in stroke mechanisms based on rammer’s deformations and stress modeling
Authors: Chepchurov M S , Voronenko V P , Chirkov A V 
Published: October 2020

Abstract
The article deals with the strength calculation issues of products by example of rammer under short-term loads in hammer drill. Based on finite element analysis’ results of the rammer geometrical model, it is proposed to select a material with a strength limit significantly exceeding the allowable residual stresses inside the rammer. The harmonic analysis allows us to estimate the rammer’s strength. The dynamic coefficient may be calculated by the use of Vibran 2.0 device (amplitude and signal frequency) and by calculation results of the maximum displacement. The FreeCAD software package was used for this. It allows to create internal scripts to automatically search for the optimal design parameters. A method of determining mechanism’s static load and its dynamic coefficient under periodic impact loads has been developed. Static loads calculations and harmonic analysis according to the developed method allow to determine structural strength of the product, to select the rammer’s material and to find the dynamic coefficient (which takes into account the stroke loads in calculations). The pro-posed calculation method may be used not only to solve the describing problem, but also for a whole class of problems related to stroke loading, where such parameters as application time of force or duration time of force’s impulse are important.
Nanodispersed additive for composite binders based on technogenic raw materials of Iraq
Authors: Ahmed Ahmed Ahmed Anees 
Published: October 2020

Abstract
The economic development of the Arab states is characterized by such trends as industrialization and urbanization, population concentration in large cities, saving land, increasing the number of storeys of buildings. Population growth in developing countries is causing acute housing needs. One of the most promising modern building materials is concrete and re-inforced concrete. The main components of concrete, as it is known, are a binder (cement), large and small aggregates. The creation of comfortable conditions is provided by the optimization of the “man-material-environment” system. The theoretical basis for the development of materials science is knowledge about geological processes and the genesis of rocks. The evolution of the development of binders goes along the way of complicating their composition and structure. In the development of materials science there is the process of controlling the structure formation of binders using nanodispersed additives. Nanodispersed additive is produced by grinding in various grinding aggregates of the silica-containing component, the cement, the carbonate constituents, superplasticizers, air-entraining additives, etc. The result is a very complex system. After we introduce a nanodispersed modifier in cements in an amount of 3 to 12%, they absolutely change the processes of structure formation. Thus, it was found that when adding a superplasticizer and a nanodispersed modifier, the compressive strength increases to 47% and the bending strength increases to 27%. The nature of the influence of the nanodispersed modifier on the properties of binders is established. Maintaining a nanodispersed modifier in the composition of Portland cement allows optimizing the process of structure formation of the component of a nanodispersed modifier and has a multifunctional value.
The influence of additives of dehydrated clay on the properties of unburned binders and concrete on their basis
Authors: Sarsenbayev N B , Kurbaniyazov S K , Saktaganova N A , Karshygayev R O 
Published: October 2020

Abstract
The purpose is development of technological bases of production of unburned alkaline binders and concrete on their basis from metallurgical and electro-thermo-phosphoric slags with an additive of the dehydrated clay with high operational properties.
In this regard the increased indicators of physical mechanical properties of unburned alkaline binders and concrete on their basis were researched with addition of 25% - dehydrated clay mixing alkalis.
The influences of fineness grinding, a type of slag and an alkaline component, curing conditions on properties unburned alkaline binders and concrete on their basis, namely on changes of average density, water absorption, strength characteristics were researched.
Thus, as a result of the conducted researches are received depending on a type of slag, an alkaline component, conditions of curing and fineness grinding of unburned alkaline binders and concrete on their basis with an additive of the ground dehydrated clay of grade from M300 to M1200.
Investigation of ground and foundation vibrations of an existing building during impact pile driving
Authors: Veshnyakov V A 
Published: October 2020

Abstract
Pile driving technology remains the most common in Arkhangelsk where the presence of soft soils is an engineering-geological feature. New construction is mainly carried out in the conditions of existing urban development. During pile driving dynamic effects that propagate in the ground can have a negative impact on existing buildings. In common conditions, a distance of more than 25 m is considered safe. Sometimes driving piles by hammer is safe for neighboring buildings at a shorter distance. Often such buildings have pile foundations. The monitoring of pile driving by diesel hammer was carried out at one of the sites in Arkhangelsk. Vertical vibration velocities were measured by a vibration analyzer with independent channels. One vibration sensor was installed on the ground surface, the other one on the foundation of a 5-storey building. Continuous recordings of vibrations allowed a detailed analysis of the driving process of each pile. The level of dynamic effects propagating in the ground changed with the penetration of the driven pile. The highest values were observed when pile foots passed through a layer of glacial deposits. Change in soil resistance to pile driving also affected the operation of diesel hammer. The level of dynamic effects increased as the distance to the driven pile decreased both on the ground surface and on the foundation of the building, while the values on the ground surface were higher. The ratio of the highest vertical peak vibration velocities on the ground surface and on the building foundation was determined by field studies.
Method of forming technological parameters in the design of vibrating cone crushers
Authors: Gerasimov M D , Chetverikov B S , Lubimyi N S , Ridvan I 
Published: October 2020

Abstract
The paper deals with issues related to expanding the possibility of using a promising direction for improving vibrating cone crushers of secondary and fine crushing. The paper deals with two major issues that need to be solved at designing and creating vibrating cone crushers. First question: the value of the ratio of the crushing force in the standard design of a cone crusher of secondary or fine crushing. The second question is the frequency of forced oscillations of the additional vibration device. The choice of the ratio of the crushing force and the value of the driving force of the vibrator is based on the output of the rational frequency of forced oscillations of the unbalanced vibration device. For the first time in this paper for this type of machine the method of dividing the circular crushing chamber into separate sections is used. Each section is a zone of wave displacement of the compressive stress in the material from the action of the crushing force. The length of the section is considered in the range of the current action of the crushing force, in which the stress in the crushed material changes from zero to maximum and again to zero. This section of the action of the crushing force is an elementary section of the force effect of the crushing force on the material. The paper contains some new terms that are caused by the need to apply a more accurate description of the kinetics of the process. The paper forms new approaches to the process of calculating the parameters of vibrating cone crushers, so it can be considered in the “in order of discussion” format.
Use of chestnut sheel (Castánea) as adsorption material for removing pollutants from natural and sewage waters: a review
Authors: Sverguzova S V , Shaikhiev I G , Fomina E V , Galimova R Z 
Published: October 2020

Abstract
The literature data on the use of grinded chestnut shells as a sorption material for removing heavy metal ions, dyes and some organic compounds from aqueous media are summarized. It is shown that a large number of publications are devoted to the study of the adsorption of ions of heavy metals with the shell of chestnut fruits. Information on the chemical composition of the chestnut shell is given. It was shown that the chestnut fruit contains cellulose, lignin and sugars in the shell most of all. It is indicated that the adsorption of many metal ions is carried out by functional groups that is a part of the biopolymers contained in the shell of chestnut fruits. It was revealed that the acidity of the medium influences the degree of extraction of metal ions from aqueous solutions, while the temperature has little effect on the sorption capacity of the shell of chestnut fruits. It is shown that it is possible to increase the sorption characteristics of pollutants by chemical modification of the chestnut shells. It has been determined that sorption isotherms in most cases are more fully described by the Langmuir model, and the kinetics of the process in all cases obeys the pseudo-second order model.
Technopark and its role in improving the competitiveness of the country’s economy: current issues in Russia and Iran
Authors: Safaie Nasser , Romanovich M A , Romanovich L G , Yarmolenko I V 
Published: October 2020

Abstract
This article presents the recent problems of infrastructure support for innovative enterprises that topical for scientists, public authorities and business representatives. The authors consider modern innovation policy as a regulator of innovation processes, consider the experience of organizing technoparks in foreign countries and the features of Russian technoparks, give the dynamics of their creation in Russia, and analyze the structure of domestic technoparks depending on their specialization and affiliation. The structure of technoparks is analyzed depending on its specialization, as well as depending on the owners. Actual problems of the organization and activity of technoparks in Russia, including on the basis of higher education institutions, are highlighted and generalized. Noting the important role of new-generation technoparks in improving the competitiveness of the country’s economy, practical recommendations for their development in modern conditions are given. The recommendations are universal and can be applied in the practical activities of authority, representatives of technoparks, universities and subjects of innovative business in Russia, Iran and other states, aimed at developing their own developments and their introduction into production. It can contribute to increase the competitiveness of the country’s economy.