scholarly journals Basic, Advanced, and Sophisticated Approaches to the Current and Forecast Challenges of Wind Energy

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8147
Author(s):  
Paweł Ligęza
Keyword(s):  
Wind Energy ◽  
Wind Turbines ◽  
Review Articles ◽  
Wide Range ◽  
Wide Group ◽  
Source Of Information ◽  
Selection Of ◽  
Energy Issues

The article is a synthetic review of contemporary wind energy issues. It was created on the basis of a survey of literature from the last two years, with mainly review articles. This work is intended to be a source of information for a wide group of scientists and students from various fields. The aim is to interest them in a wide range of topics related to wind energy and wind turbines. This may allow for the selection of an area and the undertaking of research in this interesting and future-oriented field.

The Identification of Language Impairment in the Selection of Specifically Language-Impaired Subjects

1990 ◽  
Vol 55 (3) ◽  
pp. 468-475 ◽  
Author(s):  
Rebecca J. McCauley ◽  
M. J. Demetras
Keyword(s):  
Language Impairment ◽  
Receptive Language ◽  
Research Literature ◽  
Language Impaired ◽  
Wide Range ◽  
Test Use ◽  
The Impact ◽  
Specific Number ◽  
Source Of Information ◽  
Selection Of

This review focused on the methods used to identify language impairment in specifically language-impaired subjects participating in 72 research studies that were described in four journals from 1983 to 1988. The single most frequent source of information used in the identification process was found to be test data. There was, however, considerable variability and, often, a lack of clarity regarding the specific number and identity of tests used. More specific findings on test use indicated that researchers routinely assessed both expressive and receptive language and that they used incomplete tests. When test scores used in identification and selection were examined, there was a wide range of score types, and age-equivalent scores were by far the most common and often the only type of score utilized. Conclusions are drawn regarding the impact of these findings on the interpretation and generalizability of this research literature.

Frequency-Response Matching to Optimize Wind-Turbine Test Data Correlation

1986 ◽  
Vol 108 (3) ◽  
pp. 246-251
Author(s):  
A. C. Hansen ◽  
T. E. Hausfeld
Keyword(s):  
Wind Speed ◽  
Transfer Function ◽  
Wind Turbine ◽  
Test Data ◽  
Wind Turbines ◽  
Power Coefficient ◽  
Wide Range ◽  
Averaging Time ◽  
Measured Response ◽  
Selection Of

Pre-averaging is often applied to wind turbine test data to improve correlation between wind speed and power output data. In the past, trial and error or intuition have been used in the selection of pre-averaging time and researchers and institutions have differed widely in their pre-averaging practice. In this paper a standardized method is proposed for selection of the optimum pre-averaging time. The method selects an averaging time such that the test data are low-pass-filtered at the same frequency as the response frequency of the test wind turbine/anemometer system. A theoretial method is provided for estimation of the wind system transfer function as a function of the anemometer location, rotor moment of inertia, the stiffness of the connection between the rotor and the electrical grid, hub height, rotor speed and wind speed. The method is based in proven theory, repeatable, easy to use and applicable to a wide range of wind turbines and test conditions. Results of the transfer function predictions are compared with the measured response of two wind systems. Agreement between the predicted and measured response is completely adequate for the purposes of the method. Example results of calculated averaging times are presented for several wind turbines. In addition, a case study is used to demonstrate the dramatic effects of test design and data analysis methods on the results of a power coefficient measurement.

scholarly journals How Cherkasy Online Media Utilize the Content Generated by Social Networks’ Users

2016 ◽  
pp. 49-58
Author(s):  
Svitlana Koval
Keyword(s):  
Social Networks ◽  
User Generated Content ◽  
Online Media ◽  
Citizen Journalism ◽  
Special Focus ◽  
General Audience ◽  
Media Activism ◽  
Wide Range ◽  
Source Of Information ◽  
Selection Of

In this study we explore the user-generated content as one of the most unique tools of modern online environment. The user-generated content results from the interactivity with audience that becomes possible through the Web 2.0 technologies. Being accessible and affordable to the general audience, these technologies are widely applied by the users to independently create and share their own content. The objective of the research is to explore and substantiate the nature of the user-generated content (hereinafter UGC) phenomenon as a source of information for the online media. Being a multifunctional phenomenon UGC requires a comprehensive approach to the selection of research methods. We use the methods of analysis, synthesis, systematization, and comparison to explore the content samples from the wide range of sources including the citizen journalism, media activism, complicity journalism, and marketing. A method of observation let us identify the ways of including the user-generated content to the journalists’ publications; we also use the method of classification to distinguish the different forms of UGC. Results and Conclusions. The user-generated content is increasingly becoming popular, especially among the users of social networks. Media pay much attention to the UGC, encouraging its expansion. Different forms of social networks’ content, such as video, digital images, text, infographics and combined content are widely used by journalists to produce their own media products. Cherkasy online publishers take user-generated content from the Facebook and VKontakte social networks’ personal pages for different purposes including the following: as a newsbreak, as a main text, as an addition to the product, as an illustration, as special focus determination, as an exclusive, etc. The user-generated content does not replaces the professional journalistic products, but rather complements and expands them. Special attention should be paid to the verification of the user-generated content.

scholarly journals Pitch Control of Three Bladed Large Wind Energy Converters—A Review

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8083
Author(s):  
Adrian Gambier
Keyword(s):  
Wind Energy ◽  
Wind Turbines ◽  
Control Strategies ◽  
Integrated Control ◽  
Pitch Control ◽  
Wind Speeds ◽  
Damping Control ◽  
Wide Range ◽  
Actuator Control ◽  
Large Wind

Modern multi-megawatt wind turbines are currently designed as pitch-regulated machines, i.e., machines that use the rotation of the blades (pitching) in order to adjust the aerodynamic torque, such that the power is maintained constantly throughout a wide range of wind speeds when they exceed the design value (rated wind speed). Thus, pitch control is essential for optimal performance. However, the pitching activity is not for free. It introduces vibrations to the tower and blades and generates fatigue loads. Hence, pitch control requires a compromise between wind turbine performance and safety. In the past two decades, many approaches have been proposed to achieve different objectives and to overcome the problems of a wind energy converter using pitch control. The present work summarizes control strategies for problem of wind turbines, which are solved by using different approaches of pitch control. The emphasis is placed on the bibliographic information, but the merits and demerits of the approaches are also included in the presentation of the topics. Finally, very large wind turbines have to simultaneously satisfy several control objectives. Thus, approaches like collective and individual pitch control, tower and blade damping control, and pitch actuator control must coexist in an integrated control system.

scholarly journals ANSYS CFX STUDY OF AERODYNAMIC CHARACTERISTICS DURING BLADE PROFILE ROTATION

2021 ◽  
Vol 17 (4) ◽  
pp. 153-160
Author(s):  
Andrey Proskurin ◽  
Yulia Zheglova
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Power Plants ◽  
Thermal Power ◽  
Aerodynamic Characteristics ◽  
External Energy ◽  
Electric Generator ◽  
Wide Range ◽  
Effective Development

Currently, wind energy is one of the most developing areas, which is primarily due to the absence of emissions of harmful substances into the atmosphere. Wind power allows providing electricity to remote areas, where fuel delivery, as well as the construction of thermal power plants is laborious and expensive. The effective development of wind turbines should solve the following tasks: the creation of the necessary driving force and the possibility of using a high coefficient of wind energy, which does not contradict the maintenance of the ecological balance of the territory. An electric generator for a household wind turbine must provide electricity in a wide range of rotation speeds and be able to work independently without automation and external energy sources. The study of the numerical implementation of the method of aerodynamic analysis of the wind turbine blade in rotational motion in the ANSYS CFD software package is by far the most promising and dynamically developing direction in the field of aerodynamics calculations. The results of approbation of the mixed calculation method using a dynamically variable and stationary finite-volume mesh are presented. The use of a mixed design scheme allows for calculations of wind turbines inside the building, while it becomes possible to minimize the required power for the study.

Development of the algorithm for the selection of a wind generator-based autonomous power supply system

2019 ◽  
Vol 2 (1) ◽  
pp. 8-16 ◽  
Author(s):  
P. A. Khlyupin ◽  
G. N. Ispulaeva
Keyword(s):  
Wind Turbines ◽  
Power Supply ◽  
Alternative Energy ◽  
Power Supply System ◽  
Supply System ◽  
Power Generators ◽  
Energy Devices ◽  
Wind Generator ◽  
Alternative Energy Sources ◽  
Selection Of

Introduction: The co-authors provide an overview of the main types of wind turbines and power generators installed into wind energy devices, as well as advanced technological solutions. The co-authors have identified the principal strengths and weaknesses of existing wind power generators, if applied as alternative energy sources. The co-authors have proven the need to develop an algorithm for the selection of a wind generator-based autonomous power supply system in the course of designing windmill farms in Russia. Methods: The co-authors have analyzed several types of wind turbines and power generators. Results and discussions: The algorithm for the selection of a wind generator-based autonomous power supply system is presented as a first approximation. Conclusion: The emerging algorithm enables designers to develop an effective wind generator-based autonomous power supply system.

COMBINATORIAL POLYNOMIALLY COMPUTABLE CHARACTERISTICS OF SUBSTITUTIONS AND THEIR PROPERTIES

2020 ◽  
Vol 7 (2) ◽  
pp. 34-41
Author(s):  
VLADIMIR NIKONOV ◽  
◽  
ANTON ZOBOV ◽  
Keyword(s):  
Mathematical Expectation ◽  
Point Of View ◽  
Small Range ◽  
Computational Point ◽  
Wide Range ◽  
Bijective Function ◽  
The Difference ◽  
Element Base ◽  
Selection Of

The construction and selection of a suitable bijective function, that is, substitution, is now becoming an important applied task, particularly for building block encryption systems. Many articles have suggested using different approaches to determining the quality of substitution, but most of them are highly computationally complex. The solution of this problem will significantly expand the range of methods for constructing and analyzing scheme in information protection systems. The purpose of research is to find easily measurable characteristics of substitutions, allowing to evaluate their quality, and also measures of the proximity of a particular substitutions to a random one, or its distance from it. For this purpose, several characteristics were proposed in this work: difference and polynomial, and their mathematical expectation was found, as well as variance for the difference characteristic. This allows us to make a conclusion about its quality by comparing the result of calculating the characteristic for a particular substitution with the calculated mathematical expectation. From a computational point of view, the thesises of the article are of exceptional interest due to the simplicity of the algorithm for quantifying the quality of bijective function substitutions. By its nature, the operation of calculating the difference characteristic carries out a simple summation of integer terms in a fixed and small range. Such an operation, both in the modern and in the prospective element base, is embedded in the logic of a wide range of functional elements, especially when implementing computational actions in the optical range, or on other carriers related to the field of nanotechnology.

SHAPING OF AN AUTONOMOUS POWER SYSTEM FOR GUARANTEED POWER SUPPLY WITH THE PREDOMINANCE WIND ENERGY

2018 ◽  
pp. 28-50
Author(s):  
S. G. Ignatiev ◽  
S. V. Kiseleva
Keyword(s):  
Energy Storage ◽  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Energy Demand ◽  
Diesel Generator ◽  
Average Wind Speed ◽  
Wind Speeds ◽  
Average Wind

Optimization of the autonomous wind-diesel plants composition and of their power for guaranteed energy supply, despite the long history of research, the diversity of approaches and methods, is an urgent problem. In this paper, a detailed analysis of the wind energy characteristics is proposed to shape an autonomous power system for a guaranteed power supply with predominance wind energy. The analysis was carried out on the basis of wind speed measurements in the south of the European part of Russia during 8 months at different heights with a discreteness of 10 minutes. As a result, we have obtained a sequence of average daily wind speeds and the sequences constructed by arbitrary variations in the distribution of average daily wind speeds in this interval. These sequences have been used to calculate energy balances in systems (wind turbines + diesel generator + consumer with constant and limited daily energy demand) and (wind turbines + diesel generator + consumer with constant and limited daily energy demand + energy storage). In order to maximize the use of wind energy, the wind turbine integrally for the period in question is assumed to produce the required amount of energy. For the generality of consideration, we have introduced the relative values of the required energy, relative energy produced by the wind turbine and the diesel generator and relative storage capacity by normalizing them to the swept area of the wind wheel. The paper shows the effect of the average wind speed over the period on the energy characteristics of the system (wind turbine + diesel generator + consumer). It was found that the wind turbine energy produced, wind turbine energy used by the consumer, fuel consumption, and fuel economy depend (close to cubic dependence) upon the specified average wind speed. It was found that, for the same system with a limited amount of required energy and high average wind speed over the period, the wind turbines with lower generator power and smaller wind wheel radius use wind energy more efficiently than the wind turbines with higher generator power and larger wind wheel radius at less average wind speed. For the system (wind turbine + diesel generator + energy storage + consumer) with increasing average speed for a given amount of energy required, which in general is covered by the energy production of wind turbines for the period, the maximum size capacity of the storage device decreases. With decreasing the energy storage capacity, the influence of the random nature of the change in wind speed decreases, and at some values of the relative capacity, it can be neglected.

Synthesis, Characterization and Antiproliferative Activity Assessment of a Novel 1H-5-mercapto-1,2,4 Triazole Derivative

2017 ◽  
Vol 68 (4) ◽  
pp. 745-747 ◽  
Author(s):  
Marius Mioc ◽  
Sorin Avram ◽  
Vasile Bercean ◽  
Mihaela Balan Porcarasu ◽  
Codruta Soica ◽  
...  
Keyword(s):  
Antiproliferative Activity ◽  
Biological Activities ◽  
Cancer Cell Line ◽  
Vascular Endothelial ◽  
Triazole Derivative ◽  
Activity Assessment ◽  
Wide Range ◽  
Specific Receptors ◽  
Endothelial Growth Factor ◽  
Selection Of

Angiogenesis plays an important function in tumor proliferation, one of the main angiogenic promoters being the vascular endothelial growth factor (VEGF) which activates specific receptors, particularly VEGFR-2. Thus, VEGFR-2 has become an essential therapeutic target in the development of new antitumor drugs. 1,2,4-triazoles show a wide range of biological activities, including antitumor effect, which was documented by numerous reports. In the current study the selection of 5-mercapto-1,2,4-triazole structure (1H-3-styryl-5-benzylidenehydrazino-carbonyl-methylsulfanil-1,2,4-triazole, Tz3a.7) was conducted based on molecular docking that emphasized it as suitable ligand for VEGFR-2 and EGFR1 receptors. Compound Tz3a.7 was synthesized and physicochemically and biologically evaluated thus revealing a moderate antiproliferative activity against breast cancer cell line MDA-MB-231.

Effect of Contact Ratio on Spur Gear Dynamic Load With No Tooth Profile Modifications

1996 ◽  
Vol 118 (3) ◽  
pp. 439-443 ◽  
Author(s):  
Chuen-Huei Liou ◽  
Hsiang Hsi Lin ◽  
F. B. Oswald ◽  
D. P. Townsend
Keyword(s):  
Dynamic Load ◽  
Spur Gear ◽  
Tooth Size ◽  
Contact Ratio ◽  
Gear Dynamics ◽  
Wide Range ◽  
Gear Contact ◽  
Center Distance ◽  
Selection Of ◽  
Better Than

This paper presents a computer simulation showing how the gear contact ratio affects the dynamic load on a spur gear transmission. The contact ratio can be affected by the tooth addendum, the pressure angle, the tooth size (diametral pitch), and the center distance. The analysis presented in this paper was performed by using the NASA gear dynamics code DANST. In the analysis, the contact ratio was varied over the range 1.20 to 2.40 by changing the length of the tooth addendum. In order to simplify the analysis, other parameters related to contact ratio were held constant. The contact ratio was found to have a significant influence on gear dynamics. Over a wide range of operating speeds, a contact ratio close to 2.0 minimized dynamic load. For low-contact-ratio gears (contact ratio less than two), increasing the contact ratio reduced gear dynamic load. For high-contact-ratio gears (contact ratio equal to or greater than 2.0), the selection of contact ratio should take into consideration the intended operating speeds. In general, high-contact-ratio gears minimized dynamic load better than low-contact-ratio gears.

Sign in / Sign up

Export Citation Format

Share Document