scholarly journals A Study of Improving Running Safety of a Railway Wagon with an Independently Rotating Wheel’s Flange

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1955
Author(s):  
Evgeny Mikhailov ◽  
Stanislav Semenov ◽  
Hanna Shvornikova ◽  
Juraj Gerlici ◽  
Maxim Kovtanets ◽  
...  
Keyword(s):  
Technical Solution ◽  
Friction Forces ◽  
Railway Wheel ◽  
Running Safety ◽  
Railway Wagon ◽  
Advantages And Disadvantages

The main objective of this work is to study the possibilities of improving the running safety of a railway wagon with independently rotating wheels by changing their design symmetrically mounted on an axle. The article provides a discussion of the advantages and disadvantages of using the independently rotating wheels in a bogie of railway wagons. Their increasing tendency of derailment is described. The influence of a perspective constructive scheme (PKS) of railway wagon wheels in comparison with a traditional constructive scheme (TKS) on running safety due to the climbing of a wheel flange onto a rail is studied. This work introduces a conceptual proposition of a technical solution to railway wheel design as well as containing the results of both analytical calculations as well as the results of multibody simulations. A PKS wheel design for a railway wheel is designed that allows independent rotation of its tread surface and of a guiding surface (i.e., of a flange) to each other, which both are arranged symmetrically on a wheelset axle. It brings features of the distribution of friction forces generating in a flange contact when the wheel with a TKS and with PKS move on a rail. It is possible to conclude with the help of the obtained results that the use of wheels with the PKS is advisable for the reduction of the running resistance as well as for increasing the running safety of railway wagons.

scholarly journals Development of Method for Continuous Monitoring of Tightness of Oil Product Pipeline

2020 ◽  
Vol 131 (6) ◽  
pp. 61-64
Author(s):  
D. V. Varnakov ◽  
◽  
V. V. Varnakov ◽  
R. М. Zyabirov ◽  
◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Continuous Monitoring ◽  
Technical Solution ◽  
Theoretical Justification ◽  
Advantages And Disadvantages ◽  
Oil Pipelines ◽  
Product Pipeline

The article addresses the issues of diagnosing the tightness of oil pipelines. Methods of monitoring and diagnosing the tightness of oil product pipelines are presented, their advantages and disadvantages are determined. A method and technical solution for the continuous monitoring of the tightness of an oil product pipeline is proposed. The theoretical justification of the proposed method for determining leakage based on a change in the dielectric constant of the soil is given.

scholarly journals ORGANIZATION OF POWER SUPPLY OF THE FIRST CATEGORY RECEIVERS FOR PERSPECTIVE CIVIL AVIATION AIRCRAFT

2018 ◽  
Vol 21 (6) ◽  
pp. 54-64
Author(s):  
Alexander V. Kechin ◽  
Alexander V. Levin ◽  
Sergei P. Khaliutin ◽  
Boris V. Zhmurov
Keyword(s):  
Electric Power ◽  
Power Supply ◽  
Electrical Power ◽  
Emergency Operation ◽  
Civil Aviation ◽  
Technical Solution ◽  
Operating Modes ◽  
Advantages And Disadvantages ◽  
First Category ◽  
Supply Systems

The article deals with the issue of providing electric power to the first category receivers in the emergency mode of the power supply systems operation of perspective and modernized aircraft. The analysis of the published scientific works performed both in Russia and abroad, and aimed at solving problems of analyzing abnormal operations mode, synthesizing power supply systems and controlling them in order to prevent dangerous consequences is carried out. The authors considered the ingenious technical solutions aimed at providing the necessary quality power supply for the first category receivers in the emergency operation modes of the aircraft power supply systems for the safe completion of flight and landing. The research analysis and generalization of data on the technical characteristics of units and devices developed by the world's leading manufacturers of aviation equipment and used as emergency sources of electrical power on board modern civil aviation aircraft has been completed. The advantages and disadvantages of each technical solution are determined, as well as limitations to the area of their application are formed. The analysis of perspective emergency sources of the electric power including those, which previously were not applied in aviation because of their insufficient technical perfection, for example, hydrogen electrochemical generators is carried out. Based on the performed analysis, a solution which allows improving the operating modes of the electrical batteries is proposed. The offered solution makes it possible to increase the reliability and durability of electrical batteries, as well as the power supply duration of the first category receivers from them.

New Hypothesis of Friction and Its Application to Design of a Railway Wheelset

1999 ◽  
Vol 121 (4) ◽  
pp. 768-773
Author(s):  
A. Fridberg ◽  
L. Vinnik
Keyword(s):  
Contact Mechanics ◽  
Friction Force ◽  
Normal Load ◽  
Friction Forces ◽  
Railway Wheel ◽  
Elastic Bodies ◽  
Tractive Effort ◽  
Wheel Rolling ◽  
New Hypothesis

A new hypothesis for friction forces between two elastic bodies is proposed. The hypothesis is based on contact mechanics problem. The study concentrates on the problem of a railway wheel rolling on rail under tractive effort and normal load. The effect of friction force in developing adhesion is considered. Based on the proposed hypothesis, new design of a railway wheelset has been developed and tested on Moscow Metro and tramcar.

scholarly journals Methods of calculation of the power for dough kneading with the use of blade-free working part

2020 ◽  
Vol 100 (4) ◽  
pp. 75-85
Author(s):  
Igor Stadnik ◽  
Oksana Pylypets ◽  
Mykhailo Pylypets ◽  
Volodymyr Poddubny ◽  
Olena Kolomiiets
Keyword(s):  
Technological Process ◽  
Rotation Frequency ◽  
Design Parameters ◽  
Technical Solution ◽  
Friction Forces ◽  
Cylindrical Working ◽  
Increase Productivity ◽  
Main Components ◽  
Baking Industry

Baking industry plays one of the most important roles in the production of vital food products. The quality of the bakery products can be improved through the improvement of quality in technological process of dough kneading. A technical solution for providing greater contact with the environment, reducing the duration of the process, and, accordingly, increase productivity due to the developed design of a new machine with a cylindrical working body was proposed. The ways of regulating the course of the technological process in the working chamber of a new kneading machine are considered. They are based on the change of parameters: duration of kneading, temperature, humidity, rotation frequency of the working body. A method of calculating the required power based on the process of kneading the dough is proposed. It allowed obtaining a theoretical calculation of power consumption at unknown values of the friction forces action on the kneading drum, but the known frequency of its rotation with the corresponding design parameters and factors of influence. In addition, it makes possibility to determine the effort main components that affect to the power increase of the working body drive.

scholarly journals Optimization of plow adjustment

2020 ◽  
Vol 27 ◽  
pp. 00103
Author(s):  
Damir Khaliullin ◽  
Alexandr Belinsky ◽  
Ayrat Valiev ◽  
Ruslan Lukmanov ◽  
Gaston Bourges
Keyword(s):  
Agricultural Production ◽  
Dynamic Method ◽  
Longitudinal Axis ◽  
Optimal Parameters ◽  
Friction Forces ◽  
Process Dynamics ◽  
Advantages And Disadvantages ◽  
Axis Of Symmetry ◽  
Agricultural Tractors ◽  
Reducing Energy

Optimization of plow adjustment is very important for national economy, especially in solving problems of increasing agricultural production and reducing energy consumption during plowing. One of the ways to optimize the plow adjustment is to reduce the friction forces of the plow from pressure on the bottom of the furrow and the walls of the furrow. To optimize the configuration of the plow, various methods and techniques are proposed and used that have certain advantages and disadvantages. One of the promising directions of reducing the friction forces of the plow is a dynamic method that uses adjustments of specific devices of the plow and tractor linkage mechanisms. However, one of the significant drawbacks of these adjustments is the shift of the tractor traction point from the longitudinal axis of symmetry of the tractor. The accepted working hypothesis and the studies of the process dynamics made it possible to determine the optimal parameters of the calculated and structural displacement of the tractor thrust point from the resistance line of the plow, as well as to develop recommendations for manufacturers of plows and agricultural tractors.

scholarly journals Ships’ Solutions for meeting the International requirements regarding the reduction of Air Pollution

10.18048/5304 ◽  
2017 ◽  
Vol 53 (1) ◽  
pp. 53-65
Author(s):  
Franjo Nižić ◽  
Vlado Frančić ◽  
Josip Orović
Keyword(s):  
Air Pollution ◽  
Ozone Depletion ◽  
Respiratory Diseases ◽  
Harmful Effect ◽  
Chemical Processes ◽  
Technical Solution ◽  
Negative Effects ◽  
Advantages And Disadvantages ◽  
Maritime Community ◽  
Entire Planet

Large quantities of harmful substances, gases and particles are released from the ships into the air. This leads to many unwanted chemical processes having a harmful effect on the entire planet and on the human health as well. In most cases, these processes result in ozone depletion, acid rain, global warming, appearance of dermatological and respiratory diseases and other undesirable impacts on the entire ecosystem. Aiming to reduce the adverse impact on the environment, the international maritime community has decided to regulate and set rigorous requirements for ships by introducing and implementing the Annex 6 of the MARPOL Convention. On the bases of these requirements, ships and their owners will be subjected to more stringent conditions that are primarily related to adjustment of existing ships’ engines and/or the use of environmentally friendly fuels. This paper analyses air pollution deriving from ships in general and its negative effects on the atmosphere. It also presents possible methods and solutions of adapting ships to new and more stringent requirements as well as the advantages and disadvantages of relevant technical solution

The Pros and Cons of Wall Functions

2015 ◽  
Author(s):  
Luís Eça ◽  
Gonçalo Saraiva ◽  
Guilherme Vaz ◽  
Hugo Abreu
Keyword(s):  
Shear Stress ◽  
Boundary Conditions ◽  
Daily Basis ◽  
Wall Layer ◽  
Direct Application ◽  
Slip Condition ◽  
Wall Function ◽  
Friction Forces ◽  
Wall Functions ◽  
Advantages And Disadvantages

Simulations of viscous flows based on the Reynolds-Averaged Navier-Stokes (RANS) equations have become an engineering tool used on a daily basis. One of the main goals of such calculations is to determine friction forces, which are a consequence of the shear-stress at solid walls. In RANS (and other more sophisticated mathematical models), there are two main approaches for the determination of the shear-stress at a wall: direct application of the no-slip condition, i.e. the velocity gradient is determined directly at the surface; wall functions which determine the shear-stress at the wall from semi-empirical equations applicable up to the outer edge of the so-called “wall layer/log layer”. Although the first option is physically preferable, its numerical requirements may lead to iterative convergence problems and/or excessive calculation times. Therefore, especially at high Reynolds numbers, it is not unusual to use the latter approach. In this paper we discuss the advantages and disadvantages of wall-function boundary conditions. To this end we have calculated the flow around a flat plate, conventional and laminar airfoils and a circular cylinder. The influence of the location where wall functions are applied (distance to the wall) and the effect of the Reynolds number (ranging from model to full scale applications) are discussed. Griding requirements for wall-function boundary conditions are also addressed. The results obtained with wall functions are compared with those obtained from the direct application of the no slip at the wall. The results obtained in this study show that the use of wall functions in viscous flow calculations may be justifiable or completely unacceptable depending on the flow conditions. Furthermore, it is also shown that wall-function boundary conditions also require clustering of grid nodes close to the wall, but obviously less demanding than the direct application of no slip condition.

scholarly journals Method of providing wear-resistance of the blades of paddle mixers.

2019 ◽  
pp. 32-35
Author(s):  
G. V. Petrishin ◽  
V. M. Bystrenkov ◽  
V. I. Odarchenko
Keyword(s):  
Wear Resistance ◽  
Abrasive Wear ◽  
Protective Coatings ◽  
Thermal Spraying ◽  
Technical Solution ◽  
Scientific Publications ◽  
Actual Problem ◽  
Advantages And Disadvantages ◽  
Operational Tests ◽  
Paddle Mixer

The work is devoted to solution of the actual problem to increase the service life of blade mixers used in the foundry industry. The existing methods for ensuring wear resistance of mixing blades are described, their advantages and disadvantages are indicated. Based on the analysis of scientific publications a technical solution for applying protective coatings to the blades of the mixer using gas-thermal spraying has been proposed. The results of laboratory studies of the wear rate of gas-thermal coatings from various powder mixtures of the Ni-Cr-B-Si system under conditions of abrasive wear are presented. The results of operational tests of experimental products under conditions of corrosion and abrasive wear during the operation of a paddle mixer are given. The composition of the powder mixtur ensuring maximum wear resistance of the mixer blades was developed.

Cryogenic atomic force microscopy

1991 ◽  
Vol 49 ◽  
pp. 54-55
Author(s):  
K. A. Fisher ◽  
M. G. L. Gustafsson ◽  
M. B. Shattuck ◽  
J. Clarke
Keyword(s):  
Room Temperature ◽  
Rapid Freezing ◽  
Cryogenic Temperatures ◽  
Soft Or ◽  
Electrically Conductive ◽  
Force Microscopy ◽  
Flexible Molecules ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Chemical Perturbation

The atomic force microscope (AFM) is capable of imaging electrically conductive and non-conductive surfaces at atomic resolution. When used to image biological samples, however, lateral resolution is often limited to nanometer levels, due primarily to AFM tip/sample interactions. Several approaches to immobilize and stabilize soft or flexible molecules for AFM have been examined, notably, tethering coating, and freezing. Although each approach has its advantages and disadvantages, rapid freezing techniques have the special advantage of avoiding chemical perturbation, and minimizing physical disruption of the sample. Scanning with an AFM at cryogenic temperatures has the potential to image frozen biomolecules at high resolution. We have constructed a force microscope capable of operating immersed in liquid n-pentane and have tested its performance at room temperature with carbon and metal-coated samples, and at 143° K with uncoated ferritin and purple membrane (PM).

A conduction-cooled stage for high-resolution Cryo-SEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1282-1283
Author(s):  
John G. Sheehan
Keyword(s):  
High Resolution ◽  
Liquid Nitrogen ◽  
Mechanical Stability ◽  
Cooling System ◽  
Cold Trap ◽  
Nitrogen Gas ◽  
Particulate Suspensions ◽  
Advantages And Disadvantages ◽  
Convection Cooling ◽  
Styrene Butadiene

The goal is to examine with high resolution cryo-SEM aqueous particulate suspensions used in coatings for printable paper. A metal-coating chamber for cryo-preparation of such suspensions was described previously. Here, a new conduction-cooling system for the stage and cold-trap in an SEM specimen chamber is described. Its advantages and disadvantages are compared to a convection-cooling system made by Hexland (model CT1000A) and its mechanical stability is demonstrated by examining a sample of styrene-butadiene latex.In recent high resolution cryo-SEM, some stages are cooled by conduction, others by convection. In the latter, heat is convected from the specimen stage by cold nitrogen gas from a liquid-nitrogen cooled evaporative heat exchanger. The advantage is the fast cooling: the Hexland CT1000A cools the stage from ambient temperature to 88 K in about 20 min. However it consumes huge amounts of liquid-nitrogen and nitrogen gas: about 1 ℓ/h of liquid-nitrogen and 400 gm/h of nitrogen gas. Its liquid-nitrogen vessel must be re-filled at least every 40 min.

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