scholarly journals CFD Simulations of the New Construction of Light Brattice Wall for Mine Shafts

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7239
Author(s):  
Tomasz Rokita ◽  
Paweł Kamiński ◽  
Hubert Ruta ◽  
Zbigniew Szkudlarek
Keyword(s):  
Computer Simulations ◽  
Coal Mine ◽  
The Other ◽  
Cfd Simulations ◽  
New Construction ◽  
Hoisting System

Brattice walls in mine shafts are used for various purposes, for example, permanent brattice walls can be used to separate ventilation sections. They can be also used in the case of modernization of the hoisting system, as it is in Shaft no. 1 of the Szczygłowice department, part of the Knurów-Szczyłowice coal mine. To shorten the time and reduce costs of the hoist modernization, the shaft is to be partitioned into two sections—with the hoist operating in one of them and another one being modernized in the other section. The new construction of the light brattice wall was designed for this purpose. To prove its usefulness and safety it was tested in the laboratory and computer simulations. The following paper presents CFD simulations of the brattice—its methodology and results together with an overview of works to be conducted in the shaft.

Weak Coupling Strategy for Multi-Physics CFD Simulation in Engineering Problems

2011 ◽  
Author(s):  
Makoto Yamamoto ◽  
Masaya Suzuki
Keyword(s):  
Strong Coupling ◽  
Time Scale ◽  
Weak Coupling ◽  
Particle Deposition ◽  
Cfd Simulation ◽  
The Other ◽  
Cfd Simulations ◽  
Sand Erosion ◽  
Coupling Strategy ◽  
The Difference

Multi-Physics CFD Simulation will be one of key technologies in various engineering fields. There are two strategies to simulate a multi-physics phenomenon. One is “Strong Coupling”, and the other is “Weak Coupling”. Each can be employed, based on time-scales of physics embedded in a problem. That is, when a time-scale of one physics is nearly same as that of the other physics, we have to use Strong Coupling to take into account the interaction between two physics. On the other hand, when one time-scale is quite different from the other one, Weak Coupling can be applied. Considering the present computer performance, Strong Coupling is difficult to be used in engineering design processes now. Therefore, we are focusing on Weak Coupling, and it has been applied to a number of multi-physics CFD simulations in engineering. We have successfully simulated sand erosion, ice accretion, particle deposition, electro-chemical machining and so on, with using Weak Coupling method. In the present study, the difference between strong and weak couplings is briefly described, and two examples of our multi-physics CFD simulations are expressed. The numerical results indicate that Weak Coupling strategy is promising in a lot of multi-physics CFD simulations.

scholarly journals A Double Sky-Hook Algorithm for Improving Road-Holding Property in Semi-Active Suspension Systems for Application to In-Wheel Motor

2021 ◽  
Vol 11 (19) ◽  
pp. 8912
Author(s):  
Seunghoon Woo ◽  
Donghoon Shin
Keyword(s):  
Computer Simulations ◽  
Dynamic Models ◽  
Active Suspension ◽  
The Other ◽  
Driving Mode ◽  
The Road ◽  
Suspension Systems ◽  
Active Suspension Systems ◽  
Main Disadvantage ◽  
Advanced Development

This paper presents a double sky-hook algorithm for controlling semi-active suspension systems in order to improve road-holding property for application in an in-wheel motor. The main disadvantage of the in-wheel motor is the increase in unsprung masses, which increases after shaking of the wheel, so it has poor road-holding that the conventional theoretical sky-hook algorithm cannot achieve. The double sky-hook algorithm uses a combination of damper coefficients, one from the chassis motion and the other from the wheel motion. Computer simulations using a quarter and full car dynamic models with the road conditions specified by ISO2631 showed the effectiveness of the algorithm. It was observed that the algorithm was the most effective in the vicinity of the wheel hop frequency. This paper also proposed the parameter set of the double sky-hook algorithm to differentiate the driving mode of vehicles under advanced development.

Approaches to a Concept of Simulation

2017 ◽  
Author(s):  
Inge Hinterwaldner
Keyword(s):  
Computer Simulation ◽  
Media Studies ◽  
Computer Simulations ◽  
Natural Sciences ◽  
The Other ◽  
Single Spectrum ◽  
Media Philosophy ◽  
Technical Sense ◽  
The One ◽  
Definition Of

It can be shown that the different conceptions of ‘simulation’ (the one of culture critique on the one hand and the denomination of technical applications on the other) that seem to be incompatible with each other can be reconciled on a single spectrum. Its basis in models, its replacement of reality, its lack of reference and of precession of the referent are some pejorative characteristics often emphasized in media philosophy with regard to simulations, for which the sciences applying computer simulations have no use for. It helps crossing over the views that first seem opposite to each other, but that turn out to be compatible if its root in reality is recognized and thus the representational logic is accepted at least according to the intention. The chapter combines ideas of the 'simulacrum' retrieved in the natural sciences with traces of cybernetic thinking in media studies. The whole study builds on a definition of computer simulation in the technical sense as the involvement with and the act of execution f a dynamic mathematic or procedural model that projects, depicts, or recreates a system or process.

scholarly journals Evaluating State-of-the-Art LEED-NCv4 in the U.S.

2020 ◽  
Vol 10 (3) ◽  
pp. 775
Author(s):  
Pushkar
Keyword(s):  
Environmental Quality ◽  
State Of The Art ◽  
Environmental Design ◽  
The Other ◽  
Indoor Environmental Quality ◽  
Water Efficiency ◽  
New Construction ◽  
Almost All ◽  
Very High ◽  
The U.S

To date, no empirical evidence has been published on the certification achievements of Leadership in Energy and Environmental Design for New Construction (LEED-NCv4) projects. Therefore, the aim of this study was to determine the trends in LEED-NCv4 Certified, Silver, Gold, and Platinum projects in the U.S. Boxplots were used to measure the consistency of achievement points in categories; Cliff’s δ was used to measure the effect size between possible points and achieved points in categories and credits. The findings show that (1) the categories Sustainable Sites and Energy and Atmosphere were well designed, with consistency increasing from level to level and almost all their credits achieving low–very high points; (2) the categories Water Efficiency and Indoor Environmental Quality showed an average design, and certification levels were found to be inconsistent across the projects and only approximately half of the credits achieved medium or high points, whereas the other half achieved low points; and (3) the categories Location and Transportation and Materials and Resources were the worst designed, with four certification levels found to be inconsistent across the projects and most of the credits achieved low points.

A Novel Rail Inspection Robot and Fault Detection Method for the Coal Mine Hoisting System

2019 ◽  
Vol 11 (2) ◽  
pp. 110-121 ◽  
Author(s):  
Chaoquan Tang ◽  
Gongbo Zhou ◽  
Zhaoxing Gao ◽  
Xin Shu ◽  
Pengpeng Chen
Keyword(s):  
Fault Detection ◽  
Coal Mine ◽  
Detection Method ◽  
Inspection Robot ◽  
Rail Inspection ◽  
Hoisting System

Plural Origins of Molecular Homochirality in Our Biota Part II. The Relative Stabilities of Homochiral and Mixed Oligoribotides and Peptides

1997 ◽  
Vol 52 (1-2) ◽  
pp. 89-96 ◽  
Author(s):  
Thereza Amélia Soares ◽  
Roberto Dias Lins ◽  
Ricardo Longo ◽  
Richard Garratt ◽  
Ricardo Ferreira
Keyword(s):  
Molecular Dynamics ◽  
Amino Acid ◽  
Force Field ◽  
Molecular Mechanics ◽  
Computer Simulations ◽  
The Other ◽  
Amino Acid Residues ◽  
Relative Stabilities ◽  
Amber Force Field ◽  
Cross Inhibition

Abstract By computer simulations -molecular mechanics and molecular dynamics with the amber force field (Weiner et al., (1986), J. Comp. Chem. 7, 2 30-252) -we have determined the stabilities of oligoribotide strands built with ᴅ -and ʟ-riboses, and of peptide chains with ᴅ -and ʟ-amino acid residues. In particular, complementary double-chains of oligoribotides were studied, since they are an important feature of the growing mechanism of modern nucleic acids. Peptide chains on the other hand, grow without need of a template. We found that mixed oligoribotides are less stable than homochiral ones, and that this chiral effect is less noticeable in peptide chains. The results support the interpretation that ʟ-riboses act as terminators to the template-assisted growth of oligo-r-Gᴅ (enantiomeric cross-inhibition; Joyce et al., (1987), Proc. Natl. Acad. Sci. USA 84, 4398-4402). Based on this effect, a chemical pathway is proposed which could, under assumed prebiotic conditions, bypass the hindrance of homochiral growth.

scholarly journals Social Influence of Competing Groups and Leaders in Opinion Dynamics

2020 ◽  
Author(s):  
Catherine A. Glass ◽  
David H. Glass
Keyword(s):  
Social Influence ◽  
Group Size ◽  
Computer Simulations ◽  
Parameter Space ◽  
Optimal Strategies ◽  
Opinion Dynamics ◽  
The Other ◽  
Opinion Leaders ◽  
The Impact

Abstract This paper explores the influence of two competing stubborn agent groups on the opinion dynamics of normal agents. Computer simulations are used to investigate the parameter space systematically in order to determine the impact of group size and extremeness on the dynamics and identify optimal strategies for maximizing numbers of followers and social influence. Results show that (a) there are many cases where a group that is neither too large nor too small and neither too extreme nor too central achieves the best outcome, (b) stubborn groups can have a moderating, rather than polarizing, effect on the society in a range of circumstances, and (c) small changes in parameters can lead to transitions from a state where one stubborn group attracts all the normal agents to a state where the other group does so. We also explore how these findings can be interpreted in terms of opinion leaders, truth, and campaigns.

scholarly journals Y25 freight car bogie models properties analysis by means of computer simulations

2018 ◽  
Vol 157 ◽  
pp. 03014 ◽  
Author(s):  
Tomáš Lack ◽  
Juraj Gerlici
Keyword(s):  
Tangential Stress ◽  
Computer Simulations ◽  
Simulation Analysis ◽  
The Other ◽  
Bogie Frame ◽  
Friction Dampers ◽  
Research Results ◽  
Railway Wagon ◽  
Freight Car ◽  
Railway Wheels

The article deals with the results of the simulation analysis of a railway wagon bogie model. We analysed four freight wagon bogie variants for its dynamics properties research. The bogie models correspond in general to the Y25 bogie concept. The models were created in SIMPACK software enhanced by the RAIL module. From the research results depicted in the graphs we found out, that the newly designed bogie variant gives the best results when compared to the other analysed versions. The newly designed model consists of a standard Y25 bogie frame with two Lenoire friction dampers. This bogie is equipped with longitudinal linkages on both sides. These linkages are completed with a radial torsion binding, torsion rod, between side bogie parts. The contact of railway wheels and rails generates active forces affecting the surface contact, affecting the size of the normal and tangential stress, wear surfaces of the wheel/rail, or directly the size of the derailment.

Controller Designs for a Class of Polynomial Fuzzy Models

2015 ◽  
Vol 19 (6) ◽  
pp. 796-803 ◽  
Author(s):  
Hugang Han ◽  
◽  
Yuta Higaki ◽  
Keyword(s):  
Control System ◽  
Computer Simulations ◽  
Disturbance Observer ◽  
Point Of View ◽  
Polynomial Model ◽  
The Other ◽  
System Stability ◽  
Control Performance ◽  
Fuzzy Models ◽  
Better Than

This paper proposes two polynomial fuzzy controllers in the context of the fuzzy polynomial model with a so-called lumped disturbance. One, called regular controller, is designed only based on the control system stability, while the other, called controller with disturbance observer, is designed on the basis of both control system stability and a disturbance observer proposed in this paper. Though both controllers are able to stabilize the control system, computer simulations conclude that the latter is better than the former from the point of view of the control performance when it comes to the lumped disturbance in the system concerned.

XXVIII. On the parallax of the fixed stars

1817 ◽  
Vol 107 ◽  
pp. 353-362
Keyword(s):  
Annual Variation ◽  
The Other ◽  
Considerable Proportion ◽  
Intended Purpose ◽  
New Construction ◽  
The Subject

In a former Paper on the subject of parallax, I mentioned my intention of prosecuting this investigation by means of fixed telescopes on a new construction, and which I conceived were better adapted to this purpose, than any other instrument hitherto employed. One of these was directed to α Aquilae, the other to α Cygni. Both instruments have answered the intended purpose. The observations of α Aquilae were interrupted by some alterations which I found it necessary to make in the construction of the instrument; but those of α Cygni have been continued without intermission from the month of January to the present time. Strictly speaking, a much longer period would be required (even with a perfect instrument) to determine either the exact quantity of parallax, in case it could be discovered, or the limit which it does not exceed, should it prove to be too small to be susceptible of observation; since the uncertainty in the annual variation of each star, bears a considerable proportion to the quantity to be investigated.

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