scholarly journals Modeling of asynchronous motor operation modes for the correct selection of voltage regulation devices

2020 ◽  
Vol 178 ◽  
pp. 01015 ◽  
Author(s):  
Azat Akhmetshin ◽  
George Marin ◽  
Dmitrii Mendeleev
Keyword(s):  
Voltage Drop ◽  
Asynchronous Motor ◽  
Electric Circuit ◽  
Voltage Regulation ◽  
Correct Selection ◽  
Voltage Level ◽  
Nominal Voltage ◽  
Motor Operation ◽  
Technical Solutions ◽  
Selection Of

Many electrical appliances are used in production and in everyday life, which include elements that are extremely sensitive to voltage deviations from acceptable values. Failure in their work can cause equipment failure or a breakdown in technological processes. There are a number of technical solutions to solve this problem, one of which is the using of voltage control devices such as boost transformers. The principle of operation of booster transformers is the introduction of a longitudinal EMF into the electric circuit, which provides booster. The choice of voltage regulation devices consists in determining its power and the required transformation ratio. The latter needs some justification, because it cannot be formally accepted: if it is necessary to increase the voltage, for example by 5%, it is enough to introduce a longitudinal EMF of 5% of the nominal voltage into the electric circuit. This is due to the fact that with increasing voltage from the load side, the power consumption also increases, which causes an increase in voltage drop compared to modes in the absence of voltage regulation devices. Thus, the load will receive a slightly lower voltage level in comparison with the desired one.

The Long Road to Sustainability

2018 ◽  
Author(s):  
Alexander Gillespie
Keyword(s):  
Sustainable Development ◽  
Environmental Problem ◽  
Social Sustainability ◽  
Good News ◽  
Correct Selection ◽  
The Third ◽  
Positive Indicators ◽  
Laws And Policies ◽  
Developed World ◽  
Selection Of

This book examines the idea of sustainable development, made up of economic, social, and environmental parts over the period of human history. This work suggests humanity has been unsustainable in all three areas for most of its history, although in the last few hundred years the scale of unsustainability has increased, while, simultaneously, answers have started to emerge. This conclusion can be seen in two parts, namely the economic and social sides of sustainable development and then the environmental ones. This work suggests that, with the correct selection of tools, solid and positive foundations for the economic and social sides of sustainable development is possible as the world globalizes. This is not, however, a foregone conclusion. Despite a number of recent positive indicators in this area, there are still very large unanswered questions with existing mechanisms and other gaps in the international architecture which, if not fixed, could quickly make problems of economic and social sustainability worse, not better. With the third leg of sustainable development, that for the environment, the optimism is not as strong. The good news is that science, laws, and policies have evolved and expanded to the level that, in theory, there is no environmental problem which cannot be solved. In many areas, especially in the developed world, success is already easy to measure. Where it is not easy to measure, and pessimism creeps in, is in the developing world, which is now inheriting a scale and mixture of environmental difficulties which are simply unprecedented.

scholarly journals Simulation Verification of the Contact Parameter Influence on the Forces’ Course of Cereal Grain Impact against a Stiff Surface

2021 ◽  
Vol 11 (2) ◽  
pp. 466
Author(s):  
Włodzimierz Kęska ◽  
Jacek Marcinkiewicz ◽  
Łukasz Gierz ◽  
Żaneta Staszak ◽  
Jarosław Selech ◽  
...  
Keyword(s):  
Dynamic Properties ◽  
Decisive Role ◽  
Force Sensor ◽  
Contact Forces ◽  
Correct Selection ◽  
Contact Parameter ◽  
Cereal Grain ◽  
Wide Range ◽  
The Impact ◽  
Selection Of

The continuous development of computer technology has made it applicable in many scientific fields, including research into a wide range of processes in agricultural machines. It allows the simulation of very complex physical phenomena, including grain motion. A recently discovered discrete element method (DEM) is used for this purpose. It involves direct integration of equations of grain system motion under the action of various forces, the most important of which are contact forces. The method’s accuracy depends mainly on precisely developed mathematical models of contacts. The creation of such models requires empirical validation, an experiment that investigates the course of contact forces at the moment of the impact of the grains. To achieve this, specialised test stations equipped with force and speed sensors were developed. The correct selection of testing equipment and interpretation of results play a decisive role in this type of research. This paper focuses on the evaluation of the force sensor dynamic properties’ influence on the measurement accuracy of the course of the plant grain impact forces against a stiff surface. The issue was examined using the computer simulation method. A proprietary computer software with the main calculation module and data input procedures, which presents results in a graphic form, was used for calculations. From the simulation, graphs of the contact force and force signal from the sensor were obtained. This helped to clearly indicate the essence of the correct selection of parameters used in the tests of sensors, which should be characterised by high resonance frequency.

scholarly journals Procedure for the Selection of Rubber Compound in Rubber-Metal Springs for Vibration Isolation

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1737
Author(s):  
Milan Banić ◽  
Dušan Stamenković ◽  
Aleksandar Miltenović ◽  
Dragan Jovanović ◽  
Milan Tica
Keyword(s):  
Numerical Simulation ◽  
Constitutive Model ◽  
Vibration Isolation ◽  
Correct Selection ◽  
Virtual Experiment ◽  
Rubber Compound ◽  
Key Factor ◽  
Railway Engineering ◽  
Selection Of

The selection of a rubber compound has a determining influence on the final characteristics of rubber-metal springs. Therefore, the correct selection of a rubber compound is a key factor for development of rubber-metal vibration isolation springs with required characteristics. The procedure for the selection of the rubber compound for vibration isolation of rubber-metal springs has been proposed, so that the rubber-metal elements have the necessary characteristics, especially in terms of deflection. The procedure is based on numerical simulation of spring deflection with Bergström-Boyce constitutive model in virtual experiment, with a goal to determine which parameters of the constitutive model will lead to spring required deflection. The procedure was verified by case study defined to select rubber compound for a rubber–metal spring used in railway engineering.

Generalization with Precision: The Role of Negative Teaching Examples in the Instruction of Generalized Grocery Item Selection

1986 ◽  
Vol 11 (4) ◽  
pp. 300-308 ◽  
Author(s):  
Robert H. Horner ◽  
Richard W. Albin ◽  
Ginevera Ralph
Keyword(s):  
Young Adults ◽  
Grocery Store ◽  
Item Selection ◽  
Multiple Baseline ◽  
Correct Selection ◽  
Correct Rejection ◽  
Baseline Design ◽  
Dependent Variables ◽  
Selection Of

For generalization to be functional, it must occur with a precision that results in acquired responses occurring under appropriate, nontrained conditions, and acquired responses not occurring under inappropriate, nontrained conditions. This study examines the effect of differing types of negative teaching examples on the precision with which generalized grocery item selection is learned. Within a split-multiple baseline design, six young adults identified as mildly, moderately, or severely mentally retarded were trained to select or to reject grocery items using picture cards as cues. The dependent variables were correct selection of 10 trained “positive” grocery items and the correct rejection of 20 nontrained “negative” grocery items in a nontrained grocery store. Participants were trained in a grocery store to select 10 positive grocery examples matching their picture cards and to reject either (a) a set of negative examples that were maximally different from the positive examples, or (b) a set of negative examples that were minimally different from the positive examples. Both training sets resulted in participants correctly selecting the 10 positive items in a nontrained store. Training with the “minimally different” negative examples was functionally related to improved rejection of nontrained negative items in the nontrained store. The implications of teaching with minimally different, negative examples are discussed.

scholarly journals Mechanical properties of dental restorative materials: relative contribution of laboratory tests

2003 ◽  
Vol 11 (3) ◽  
pp. 162-167 ◽  
Author(s):  
Linda Wang ◽  
Paulo Henrique Perlatti D'Alpino ◽  
Lawrence Gonzaga Lopes ◽  
José Carlos Pereira
Keyword(s):  
Mechanical Properties ◽  
Laboratory Tests ◽  
Clinical Performance ◽  
Dental Materials ◽  
Correct Selection ◽  
Relative Contribution ◽  
Dental Restorative Materials ◽  
Restorative Materials ◽  
Dental Restorative ◽  
Selection Of

A wide variety of dental products that are launched on the market becomes the correct selection of these materials a difficult task. Although the mechanical properties do not necessarily represent their actual clinical performance, they are used to guide the effects of changes in their composition or processing on these properties. Also, these tests might help somehow the clinician to choose once comparisons between former formulations and new ones, as well as, with the leading brand, are highlighted by manufactures. This paper presents a review of the most important laboratory tests. In this manner, the knowledge of these tests will provide a critical opinion related to the properties of different dental materials.

Assessment of efficiency of distribution centre at different variants of freight traffic consolidation

2021 ◽  
pp. 22-27
Author(s):  
Elena Dmitrievna Pserovskaya ◽  
◽  
Anna Pavlovna Grefenshteyn ◽  
Keyword(s):  
Potential Benefit ◽  
High Efficiency ◽  
Positive Influence ◽  
Correct Selection ◽  
Freight Traffic ◽  
Distribution Centre ◽  
Selection Of

For the determination of a potential benefit from creation of a distribution centre the paper proposes a method and presents results of calculation of a decrease of total number of rides and total run of automobiles at various variants of goods consolidation. The authors have established a positive influence of the centre on intracity transportation. At the same time, high efficiency of the considered technology can be reached by involvement of a bigger number of consignees and by consolidation of a relatively small number of goods batches in one automobile at efficient routing and correct selection of location of a distribution centre.

The use of premix in feeding of young pigs on fattening

2020 ◽  
pp. 54-59
Author(s):  
A. S. Ivanova ◽  
N. V. Dunaeva
Keyword(s):  
Positive Impact ◽  
Live Weight ◽  
Feed Additives ◽  
Correct Selection ◽  
Control Group ◽  
Pork Meat ◽  
Large White ◽  
Young Pigs ◽  
Experimental Group ◽  
Selection Of

Increasing the production of pork meat requires careful work not only in terms of breeding, but also in the organization of complete feeding of animals, the correct selection of feed and feed additives containing the necessary nutrients. The purpose of the work was to analyze the use of premix in feeding young pigs on fattening. Two groups of fattening young pigs (Large White×Landrace) have been selected for the researches using the method of analogous groups, taking into account the breed, age, and live weight per 20 heads in each group with a live weight of 35 kg. Pigs of the control group have received the main economic diet, and animals of the experimental group have received an additional premix Khutorok at the rate of 10 g of premix per 1 kg of feed. The results have shown that the best age to reach 100 kg was in the experimental group of pigs – 215,8 days, which received premix with feed that characterizes their higher precocity by 36,3 days (P < 0,001) than in the control group of animals. The use of this premix had a positive impact on the livability of young animals, in the experimental group it was by 9,3 abs.% more than in the control group of animals. Thus, the best fattening traits have been possessed by young pigl of the experimental group have been received the premix Khutorok in their diet at the rate of 10 g of premix per 1 kg of feed. The obtained data indicate the feasibility of using the premix Khutorok in the feeding pigs for fattening.

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