scholarly journals Investigation of hydraulic fitting losses

2018 ◽  
Vol 168 ◽  
pp. 02011 ◽  
Author(s):  
Marian Bojko ◽  
Milada Kozubková
Keyword(s):  
Flow Direction ◽  
Experimental Methods ◽  
Numerical Approach ◽  
Model Verification ◽  
Hydraulic Systems ◽  
Mathematical Methods ◽  
Standards And Regulations ◽  
Definition Of ◽  
Resistance Coefficients

Fluid flow in hydraulic systems, fittings, and piping causes hydraulic losses due to the change of flow direction and friction in the fluid. The main consequence of the resulting losses is the increase in the overall pressure gradient of the circuit. The paper is focused on the investigation of valve losses and the determination of resistance coefficients, the definition of which depends on the valve type. Methods of determination are of two types, i.e. experimental methods and mathematical methods. In the case of experimental methods, the procedures prescribed by the standards and regulations must be respected. Mathematical methods are related to defining an appropriate mathematical model and numerical approach. Both methods are applied to the ball valve and model verification is performed at the same time. The output of the thesis is the methodology for determination of resistance coefficients of valves with other diameters and other flowing media based on verified mathematical modeling.

THE PROBLEM OF IDENTIFICATION OF HYDRAULIC RESISTANCE COEFFICIENTS IN MAKISTRAL GAS PIPELINE

2021 ◽  
pp. 6-11
Author(s):  
G. Gasymov
Keyword(s):  
Hydraulic Resistance ◽  
Group Identification ◽  
Numerical Approach ◽  
Transportation Systems ◽  
Gas Pipeline ◽  
Closed Loops ◽  
Hydraulic Network ◽  
Resistance Coefficients ◽  
Operating Regimes

A numerical approach, based on obtaining design formulas for the determination of hydraulic resistance coefficients of sites in pipeline transportation systems in the presence of the results of observations over a gas pipeline operating regimes, is proposed. The representation of the hydraulic network in the form of a directed graph allows to essentially reduce the number of equations in the system down to the number of closed loops. In the software implementation of the method described, for the solution of practical problems, group identification of the hydraulic resistance coefficients is provided for every eventuality.

A Short-Gage-Length Extensometer and Its Application to the Study of Crankshaft Stresses

1942 ◽  
Vol 9 (1) ◽  
pp. A15-A20
Author(s):  
C. W. Gadd ◽  
T. C. Van Degrift
Keyword(s):  
Experimental Methods ◽  
Gage Length ◽  
Mathematical Treatment ◽  
Mathematical Methods ◽  
Elastic Stresses ◽  
Machine Elements

Abstract The mathematical methods of determining elastic stresses in machine elements, particularly those of irregular contour, may be excessively complex, so resort is frequently made to approximate calculations, which tend to lose accuracy while achieving simplicity. As a result a constant effort is made to supplement the mathematical treatment with experimental methods of studying stress. In this paper, the authors describe a short-gage-length extensometer and explain its application in the determination of crankshaft stresses. This instrument meets the requirement of convenience in operation, which is so essential in assuring that it will be used for the study of localized stresses.

A Numerical Approach to the Design of Sailing Yacht Masts

1991 ◽  
Author(s):  
Dario Boote ◽  
Mario Caponetto
Keyword(s):  
Stress Analysis ◽  
Numerical Approach ◽  
Load Model ◽  
Peculiar Characteristic ◽  
Correct Calculation ◽  
Non Linear ◽  
Complete Procedure ◽  
Sailing Yacht ◽  
Definition Of

In this paper a complete procedure for the design of sailing yacht rigs is presented. The procedure starts from the definition of the load model and the determination of the aerodynamic forces developed by sails and continues with the stress analysis of the rig in the non-linear domain. For the correct calculation of the sail forces a program has been realised by the authors on the basis of the lifting surface theory. For stress analysis, another dedicated program has been developed starting from a multipurpose finite element code operating in the non-linear domain, A peculiar characteristic of this procedure is that it can be run on a personal computer.

scholarly journals DETERMINATION OF THE STANDARD RESISTOR TEMPERATURE COEFFICIENTS AND THEIR UNCERTAINTIES

2019 ◽  
Vol 21 (3) ◽  
pp. 219
Author(s):  
Muhammad Azzumar ◽  
Lukluk Khairiyati ◽  
Agah Faisal
Keyword(s):  
Temperature Coefficient ◽  
Numerical Approach ◽  
Alpha Coefficient ◽  
Measurement Result ◽  
Temperature Coefficients ◽  
Taylor Series Approximation ◽  
Measurement Results ◽  
Beta Coefficient ◽  
Definition Of

<p>SNSU TK-BSN’s capability in determining the temperature coefficients of a standard resistor has been improved. The temperature coefficient is one of the important parameter in determining the definition of the standard resistor. Currently, the measurement result has been reported together with the measurement uncertainty. The determination itself is based on a numerical approach of Taylor Series Approximation (TSA) instead of based on a fitting to a certain equation. And by this determination, the uncertainty was calculated. The determination was validated by comparing the measurement result committed by SNSU TK-BSN to that of by the manufacturer. The equation for the temperature coefficient follows the parabolic equation with an alpha coefficient of -5.30 x 10-8 Ω/Ω/°C and beta coefficient of -4.70 x 10-8 Ω/Ω/°C<sup>2</sup>, with the respective uncertainties of 2.4 x 10-8 Ω/Ω/°C and 1.6x 10-8 Ω/Ω/°C<sup>2</sup>, respectively. SNSU TK-BSN measurement results in determining the temperature coefficient in agreement with the manufacturer's measurement results show an appropriate value. This correspondence has an equivalent degree of 0.20 for the alpha temperature coefficient and 0.27 for the beta coefficient.</p>

scholarly journals Development of a system of transport-interchange hubs in urban transport network

2021 ◽  
Vol 112 ◽  
pp. 00015
Author(s):  
Oleg V. Moskvichev ◽  
Svetlana A. Leonova
Keyword(s):  
Optimal Choice ◽  
Urban Transport ◽  
Transport Systems ◽  
Mathematical Methods ◽  
Passenger Traffic ◽  
Transport Services ◽  
Scientific Results ◽  
Integer Programming Problems ◽  
Definition Of

The paper considers the issues of the formation of a system of transport interchange hubs (TIH), associated with the determination of the location of TIH in order to improve the quality of the provided transport services. The model of the optimal choice of TIH system is presented in the form of a linear Boolean programming problem. The paper gives the factors that reduce the average travel time around the city due to the formation of a system of transport hubs. In order to solve the problem of the choice of TIH locations, the approach based on the definition of “effective interchange hubs” is proposed. The determination of effective interchange hubs is carried out according to the following algorithm. First we found a list of non-stop (direct) rides. Then, we consider the rides for which there is no direct route or for which there is such a route, but this revealed connecting route will take less time. These hubs are efficient. Next, a list of effective interchange hubs is determined and the amount of passenger traffic at each hub is specified. Using mathematical methods to solve integer programming problems, it is possible to select such efficient interchange hubs, in which it is advisable to create transport interchange hubs. These scientific results can be used in programs and projects for the development of urban transport systems in the development of basic requirements for the formation of transport hubs.

State Failure and the Political Violence Phenomenon: A Comparative Analysis of Iraq and Syria Cases

2016 ◽  
Vol 4 (2) ◽  
pp. 170 ◽  
Author(s):  
K. Eylem Özkaya Lassalle
Keyword(s):  
Cold War ◽  
Political Violence ◽  
State Failure ◽  
The Political ◽  
Collective Violence ◽  
Short Run ◽  
Definition Of ◽  
The Cold War

The concept of failed state came to the fore with the end of the Cold War, the collapse of the USSR and the disintegration of Yugoslavia. Political violence is central in these discussions on the definition of the concept or the determination of its dimensions (indicators). Specifically, the level of political violence, the type of political violence and intensity of political violence has been broached in the literature. An effective classification of political violence can lead us to a better understanding of state failure phenomenon. By using Tilly’s classification of collective violence which is based on extent of coordination among violent actors and salience of short-run damage, the role played by political violence in state failure can be understood clearly. In order to do this, two recent cases, Iraq and Syria will be examined.

DEFINITION OF TIME SPENT ON REPAIR OF BUS TRANSMISSION UNITS TAKING INTO ACCOUNT TECHNOLOGICAL EQUIPMENT RELIABILITY

2020 ◽  
Vol 2020 (9) ◽  
pp. 29-33
Author(s):  
Sergey Bulatov
Keyword(s):  
Negative Impact ◽  
Probabilistic Method ◽  
Technological Equipment ◽  
Quality And Safety ◽  
Transmission Unit ◽  
Equipment Reliability ◽  
Hours Of Work ◽  
Definition Of ◽  
Time Decrease

The paper purpose is the effectiveness estimation in the technological equipment use, taking into account its reliability and productivity for defective transmission units of buses. The problem consists in the determination of time to be spent on repair of bus transmission units taking into account technological equipment reliability. In the paper there is used a probabilistic method for the prediction bus transmission units, and also a method of the dynamics of averages which allow ensuring minimum of costs for units downtime during repair and equipment cost. The need for repair of transmission units (gear box) arises on an average after 650 hours, the average productivity of the bench makes 4.2 bus / hour. The bench fails on the average after 4600 hours of work, the average time of the bench makes 2 hours. In such a way the solution of the problem specified allows analyzing the necessity of time decrease for transmission unit repair to avoid long downtimes of buses in repair areas without negative impact upon high repair quality and safety during the further operation.

Tests of jackhammers (formation of bench techniques)

2020 ◽  
pp. 28-32
Author(s):  
V.S. Vanaev
Keyword(s):  
Impact Energy ◽  
Bench Tests ◽  
Measuring Complex ◽  
Energy Indicators ◽  
Definition Of ◽  
Determination Of Parameters ◽  
Dynamic Indicators

Development of complex determination of parameters of jackhammers at bench tests is studied. The modern support of tests of jackhammers for the purpose of definition of their energy, vibration and noise indicators is considered. Descriptions of the SORP universal bench and UIPU measuring complex are given. Keywords jackhammer, bench, tests, processing object, energy indicators, impact energy, dynamic indicators [email protected]

The methodology of experimental research of the feed components extrusion process in order to improve its energy performance

2020 ◽  
pp. 147-152
Author(s):  
E. M. Ratnikov ◽  
D. O. Milko
Keyword(s):  
Experimental Studies ◽  
Energy Performance ◽  
Extrusion Process ◽  
Mathematical Methods ◽  
Screw Extruder ◽  
Mathematical Planning ◽  
Factors Affecting ◽  
Extrusion Processing ◽  
Definition Of

Annotation Purpose. Development of a program and methods for conducting experimental studies of the extrusion process with the definition of parameters and modes of operation of the extruder to improve its energy performance. Methods. Methods of mathematical statistics, synthesis, analysis, description and modeling were used. Results. The application of mathematical methods, in particular mathematical planning, reduces the number of experiments several times, and allows to evaluate the role of influencing factors, obtain a mathematical model of the process and determine the optimal conditions for its parameters and modes, etc. Conclusions. The methodology for experimental studies of a screw extruder is presented with the necessary equipment and methodology for processing the obtained experimental data. A mathematical method of planning, which reduces the number of experiments several times, allows us to evaluate the role of factors affecting productivity and energy intensity is presented. Keywords: extruder, auger, nutrients, research methodology, extrusion, processing, feed.

Actual issues of valuation of businesses of the economic entity

2017 ◽  
Vol 31 (2) ◽  
pp. 156-162 ◽  
Author(s):  
O. V. Schneider
Keyword(s):  
Discount Rate ◽  
Accurate Prediction ◽  
Economic Activities ◽  
Business Valuation ◽  
Economic Entity ◽  
The World ◽  
Definition Of

The article summarizes the main approaches in the definition of business valuation the economic entity. In the process of business valuation, taking into account the risks of financial and economic activities necessary to obtain information on what stage the owner implements the business will receive income. The most difficult task is the impossibility of accurate prediction in determining the level of income and the determination of a discount rate capitalization of future incomes due to the instability of the economy, both in the country and around the world.

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