scholarly journals SOFTWARE APPLICATION FOR DETERMINATION OF BRAKE EFFICIENCY OF FREIGHT TRAINS ACCORDING TO THE RULES OF GOST 34434-2018

2020 ◽  
pp. 107-119
Author(s):  
O.M. Safronov ◽  
◽  
Y.Y. Vodiannikov ◽  
O.G. Makeieva
Keyword(s):  
Cast Iron ◽  
Axial Load ◽  
Disc Brake ◽  
Calculation Algorithm ◽  
Freight Train ◽  
Software Application ◽  
Technical Requirements ◽  
Complete Automation ◽  
Computational Research

Calculation algorithm for braking distances of a freight train and recalculation on cast iron brake shoes in accordance with new rules of GOST 34434-2018 "BRAKE SYSTEMS OF FREIGHT CARS. Technical requirements and calculation rules " is given. According to the above mentioned algorithms, a program was drawn up in the Excel environment, intended to complete automation of the process of computational research to determine the braking efficiency of a freight train. The program is universal, as it allows studying brake systems of different design: with one and two brake cylinders; with one-sided and two-sided application of brake shoes on wheels; with disc brake. Examples of calculation studies of the braking efficiency of the open-top car with an axial load of 25 tons are shown.

scholarly journals Modeling the Depth of Surface Cracks in Brake Disc

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3890
Author(s):  
Wojciech Sawczuk ◽  
Mateusz Jüngst ◽  
Dariusz Ulbrich ◽  
Jakub Kowalczyk
Keyword(s):  
Cast Iron ◽  
Crack Depth ◽  
Brake Disc ◽  
Disc Brake ◽  
Surface Cracks ◽  
Braking System ◽  
Brake Discs ◽  
Regression Functions ◽  
Metallic Object

The article presents the state of knowledge and research in the field of surface cracks occurring in disc braking systems of rail and car vehicles. The craze formed during the operation of vehicles is particularly dangerous and leads to breaking the disc into several pieces. It may lead to a loss of braking force and damage to the entire disc brake caliper. The main aim of the research is to identify surface cracks in brake discs made of cast iron and use experimental methods to estimate their depth. Research were conducted on the disc braking system developed by the authors. In examining the location and depth of cracks, the penetration method, ultrasound, as well as a special probe were used. This device measures the crack depth based on the electrical resistance between two points on the surface of the metallic object. The tests showed that the first microcracks on the brake discs appeared after 309 braking tests on the test stand. In addition, it was observed that the surface cracks length of the disc increased linearly to depth until they reached about 11.5–12 mm with corresponded to crack lengths in the range of 65–70 mm. However, determination of the regression functions presented in the article allows to estimate the depth of surface cracks up to 70 mm long on cast iron brake discs by measuring their length.

scholarly journals ASPECTS OF BRAKING EFFICIENCY CRITERIA FOR FREIGHT WAGONS UNDER THE LATEST RULES OF HOST 34434-18

2021 ◽  
pp. 22-30
Author(s):  
Oleksandr Safronov ◽  
◽  
Yurii Vodiannikov ◽  
Keyword(s):  
Axial Load ◽  
Axial Loads ◽  
Pressure Force ◽  
Significant Discrepancy ◽  
Freight Train ◽  
Pressing Force ◽  
Technical Requirements ◽  
Actual Force ◽  
Braking Distance ◽  
Freight Wagons

The paper deals with the analysis of the braking efficiency criteria for freight trains formed with wagons that have increased axle load up to 294.3 kN (30 ts) when moving at speeds up to 120 km/h inclusive. Increasing the efficiency of freight trains by increasing the technical and economic performance of cars by increasing the axial load to 294.3 kN (30 ts) and train speeds up to 160 km/h led to the development of technical requirements and rules for braking systems set out in HOST 34434-18. According to the new rules and requirements, the following are accepted as criteria for the braking efficiency of freight wagons, that is, up to the maximum values of the braking distances of the freight train on the site in the specified intervals of speeds of axial loads; calculated coefficients of force of pressing of composite blocks on wheels at braking; the pressing force of the composite pads on the axis in terms of cast iron pads. The calculation of the maximum allowable value of the braking distance of the freight train is performed based on the actual pressing forces and the actual friction coefficients. The paper shows that the specific braking forces obtained using the actual pressing forces exceed the calculated specific braking forces using the calculated coefficients. Based on the above-mentioned, it is concluded that the braking efficiency criteria with reference to the maximum allowable values of the braking distances and the calculated coefficients of the pressing force have a significant discrepancy between each other. It is proposed to use the actual pressure force coefficients instead of the calculated coefficients to assess the braking efficiency of the freight train. The paper presents the permissible values of the actual force values of pressing the pads on the wheels for wagons with axial load (230.5 - 294.3) kN at speeds up to 120 km/h inclusive, for which the braking distance criterion of the freight train is observed. Key words: criterion, braking efficiency, freight train, axial load, braking distance, specific braking force, calculated coefficients, actual coefficient.

scholarly journals DETERMINATION OF FREIGHT WAGON PARAMETERS ACCORDING TO THE SPECIFIED CRITERIA OF THE TRAIN BRAKING EFFICIENCY (four-axle gondola cars, covered cars, platforms, dump cars)

2021 ◽  
pp. 101-110
Author(s):  
Oleksandr Safronov ◽  
◽  
Yurii Vodiannikov ◽  
Olena Makeieva
Keyword(s):  
Axial Load ◽  
Gear Ratio ◽  
Normative Values ◽  
Power Relationship ◽  
Freight Train ◽  
Braking Performance ◽  
Brake Pads ◽  
Braking System ◽  
Braking Distance

The lack of normative values of the actual coefficients in the new rules of HOST 34434-2018 do not allow to implement and determine the optimal characte-ristics of the brake according to pre-accepted conditions of braking efficiency (braking distance), which causes uncertainty in solving this problem. The uncertainty is that the choice of characteristics of the braking system of the freight wagon has to be done by searching a large number of options. In this regard, the paper provides tools for determining the actual pressing force of the brake pads on the wheels, which complies with the specified braking performance of the freight train. As a tool, universal formulas are used in the form of a power relationship between the actual force of the brake pads and the braking distance of the freight train. The coefficients of universal formulas are obtained on the basis of computer modeling. Numerous examples show that the error in the use of universal formulas in calculation studies does not exceed 1% compared with the calculation method according to HOST 34434-2018. The values of the actual coefficients depending on the axial load of the wagon and the speed at which the braking distances of the freight train satisfy the normative minimum allowable values are given. It is shown that calculation studies performed according to the universal formulas in the EXCEL environment allows to fully automating the computational process. A method for determining the gear ratio of the brake lever of a freight wagon, according to which the specified braking efficiency is performed, is proposed. The proposed procedure allows you to perform a variety of studies to select the optimal parameters of the braking system of freight wagons that meet the specified requirements of braking efficiency, and greatly facilitates the calculation studies. Key words: аctual coefficient, braking distance, speed, axial load, power dependence, coefficients, gear ratio.

scholarly journals Intra-Laboratory Validation of Alpha-Galactosidase Activity Measurement in Dietary Supplements

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1566
Author(s):  
Elena Fabris ◽  
Michela Bulfoni ◽  
Alessandro Nencioni ◽  
Emanuele Nencioni
Keyword(s):  
Dietary Supplements ◽  
Good Manufacturing Practice ◽  
Activity Measurement ◽  
Intermediate Precision ◽  
Method Performance ◽  
Intestinal Gas ◽  
Technical Requirements ◽  
Ich Guidelines ◽  
Alpha Galactosidase

Introduction: Alpha-galactosidase (α-Gal) is an enzyme responsible for the hydrolyzation of glycolipids and glycoprotein commonly found in dietary sources. More than 20% of the general population suffers from abdominal pain or discomfort caused by intestinal gas and by indigested or partially digested food residuals. Therefore, α-Gal is used in dietary supplements to reduce intestinal gases and help complex food digestion. Marketed enzyme-containing dietary supplements must be produced in accordance with the Food and Drug Administration (FDA) regulations for Current Good Manufacturing Practice (cGMPs). Aim: in this work we illustrated the process used to develop and validate a spectrophotometric enzymatic assay for α-Gal activity quantification in dietary supplements. Methods: The validation workflow included an initial statistical-phase optimization of materials, reagents, and conditions, and subsequently a comparative study with another fluorimetric assay. A final validation of method performance in terms of specificity, linearity, accuracy, intermediate-precision repeatability, and system precision was then executed. Results and conclusions: The proven method achieved good performance in the quantitative determination of α-Gal activity in commercial food supplements in accordance with the International Council for Harmonisation of Technical Requirements for Pharmaceuticals (ICH) guidelines and is suitable as a rapid in-house quality control test.

scholarly journals Reverse phase-liquid chromatography assisted protocol for simultaneous determination of lamivudine and tenofovir disoproxil fumarate in combined medication used to control HIV infection: an investigative approach

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Vaibhav S. Adhao ◽  
Suraj R. Chaudhari ◽  
Jaya P. Ambhore ◽  
Sunil Sangolkar ◽  
Raju R. Thenge ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Hiv Infection ◽  
Simultaneous Determination ◽  
Tenofovir Disoproxil Fumarate ◽  
Solvent System ◽  
Array Detector ◽  
Technical Requirements ◽  
Relative Standard ◽  
Limit Of Quantitation

Abstract Background Human immunodeficiency virus (HIV) causes severe life-threatening condition, i.e., AIDS. HIV destabilises an individual’s ability to prevent infection. Therefore, the combine medication lamivudine (LVD) and tenofovir disoproxil fumarate (TDF) are prescribed to suppress the amount of HIV infection in individual’s body; thus, the individual’s immune system could function properly. Consequently, the objective of present research work was to investigate robust and sensitive liquid chromatography avenue for simultaneous determination of lamivudine and tenofovir disoproxil fumarate in pure material and combined dosage form. Results The reversed-phase chromatographic separation has been performed through Hypersil BDS C18 column using solvent system composed of 10 mM potassium dihydrogen phosphate (pH 4.0): acetonitrile (60:40% v/v). The determination was executed at 30 oC at 1 mL/min rate for flow of solvent system through column. The eluents of column were monitored at 265 nm using Photodiode Array detector has revealed admirable retention times, i.e., 4.67 and 8.78 min for both drugs, respectively. The calibration curve demonstrated excellent linearity in the range of 10–50 μg/mL for lamivudine and tenofovir disoproxil fumarate with better determination coefficients was more than (r2 0.999). Conclusion The estimable method was effectively validated with respect to accuracy, precision, sensitive (limit of detection and limit of quantitation), robustness, ruggedness, and for selectivity and specificity. The value less than 2 for percentage relative standard deviation for accuracy, precision, robustness, and ruggedness satisfying the acceptance criteria as per procedure of International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use.

scholarly journals Three-dimensional CFD modeling of thermal behavior of a disc brake and pad for an automobile

2020 ◽  
Vol 15 (4) ◽  
pp. 543-549
Author(s):  
Haydar Kepekci ◽  
Ergin Kosa ◽  
Cüneyt Ezgi ◽  
Ahmet Cihan
Keyword(s):  
Cast Iron ◽  
Friction Coefficient ◽  
Elevated Temperatures ◽  
Gray Cast Iron ◽  
Three Dimensional ◽  
Brake System ◽  
Gray Cast ◽  
Cfd Modeling ◽  
Disc Brake ◽  
Disc Material

Abstract The brake system of an automobile is composed of disc brake and pad which are co-working components in braking and accelerating. In the braking period, due to friction between the surface of the disc and pad, the thermal heat is generated. It should be avoided to reach elevated temperatures in disc and pad. It is focused on different disc materials that are gray cast iron and carbon ceramics, whereas pad is made up of a composite material. In this study, the CFD model of the brake system is analyzed to get a realistic approach in the amount of transferred heat. The amount of produced heat can be affected by some parameters such as velocity and friction coefficient. The results show that surface temperature for carbon-ceramic disc material can change between 290 and 650 K according to the friction coefficient and velocity in transient mode. Also, if the disc material gray cast iron is selected, it can change between 295 and 500 K. It is claimed that the amount of dissipated heat depends on the different heat transfer coefficient of gray cast iron and carbon ceramics.

Spectrographic Analysis of Cast Iron Using Fused Buttons

1971 ◽  
Vol 25 (3) ◽  
pp. 342-344 ◽  
Author(s):  
John P. Cummings ◽  
Ronald H. Hall ◽  
Ronald J. Plenzler
Keyword(s):  
Weight Loss ◽  
Cast Iron ◽  
High Voltage ◽  
Analytical Method ◽  
White Cast Iron ◽  
Inert Atmosphere ◽  
Spectrographic Analysis ◽  
Analytical Results ◽  
Good Homogeneity

This paper presents an analytical method for the determination of minor metals in white cast iron fused buttons. This method enables the measurement of metals in cast iron with rapidity and excellent analytical results. Buttons of 40 g appear to be ideal but smaller button samples can be tolerated. The fused buttons have good homogeneity, very slight weight loss, and no significant change in composition. Metal cast spectrochemical samples are analyzed in an inert atmosphere utilizing a high voltage spark.

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