scholarly journals The effect of temperature on the tribological characteristics of high speed steels under conditions of friction without lubricant on the structural steel 30HGSA

2021 ◽  
Vol 2131 (5) ◽  
pp. 052016
Author(s):  
E V Fominov ◽  
C G Shuchev
Keyword(s):  
Structural Steel ◽  
Contact Zone ◽  
High Speed ◽  
Normal Load ◽  
Dissipative Structures ◽  
Effect Of Temperature ◽  
Friction Zone ◽  
Pin On Disk ◽  
Different Levels ◽  
Zone Temperature

Abstract This article focuses on the study of the effect of temperature in the contact zone on the process of dissipative structures formation on the surfaces of specimens made of high speed steels (HSS) grades with different levels of thermal entropy and absolute thermo-EMF under conditions of friction without lubricant on the structural steel 30HGSA. Tribological tests were performed on the tribometer which implemented a scheme of friction “pin on disk” at constant sliding speed and normal load values. The temperature in the friction zone has changed artificially from 100 to 300°C with a special intelligent heating device. It has been established experimentally that in the process of friction of HSS specimens characterized by low values of absolute thermo-EMF the dissipative structures thickness growth rate over time at temperatures of 200-250oC decreases or remains virtually unchanged; friction coefficient decreases with the increase in temperature. For specimens made of steels with high absolute thermo-EMF the rates of dissipative structures thickness growth and their utmost thicknesses increase when the contact zone temperature increases, which is accompanied by an increase in friction coefficients.

Influence of the choice of wear criterion on the life of high speed machine manual taps

2020 ◽  
pp. 74-78
Author(s):  
A.E. Dreval
Keyword(s):  
Service Life ◽  
Structural Steel ◽  
Tool Life ◽  
High Speed ◽  
High Speed Steel ◽  
Parameter Dependence ◽  
Limiting State ◽  
Thread Cutting ◽  
Failure Life ◽  
High Speed Machine

The assessment of the limiting state of high-speed machine-manual taps in the processing of structural steel billets is considered. A general multi-parameter dependence is developed for calculating the criterion of allowable wear, which makes it possible to rationally use the tool life and normalize the cut amount during regrinding. Keywords thread cutting, tap, angle of the cutting part, criterion, high-speed steel, wear, failure, life, service life. [email protected]

An experimental and theoretical study of the abrasion performance of digital light processing parts

2020 ◽  
pp. 095440542098133
Author(s):  
Mehdi Kazemi ◽  
Abdolreza Rahimi
Keyword(s):  
Layer Thickness ◽  
Normal Load ◽  
Digital Light Processing ◽  
One Step ◽  
Pin On Disk ◽  
The Relationship ◽  
Influential Parameters ◽  
Disk Method ◽  
Normal Angle

Generally, interactions at surface asperities are the cause of wear. Two-Thirds of wear in industry occurs because of the abrasive or adhesive mechanisms. This research presents an analytical model for abrasion of additive manufactured Digital Light Processing products using pin-on-disk method. Particularly, the relationship between abrasion volume, normal load, and surface asperities’ angle is investigated. To verify the proposed mathematical model, the results of this model are verified with the practical experiments. Results show that the most influential parameters on abrasion rate are normal load and surface’s normal angle. Abrasion value increases linearly with increasing normal load. The maximum abrasion value occurs when the surface’s normal angle during fabrication is 45°. After the asperities are worn the abrasion volume is the same for all specimens with different surface’s normal angle. Though layer thickness does not directly affect the wear rate, but surface roughness tests show that layer thickness has a great impact on the quality of the abraded surface. When the thickness of the layers is high, the abraded surface has deeper valleys, and thus has a more negative skewness. This paper presents an original approach in abrasion behavior improvement of DLP parts which no research has been done on it so far; thus, bringing the AM one step closer to maturity.

scholarly journals Subsidising urban and sub-urban transport – distributional impacts

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Nils Fearnley ◽  
Jørgen Aarhaug
Keyword(s):  
Public Transport ◽  
High Speed ◽  
High Income ◽  
Urban Transport ◽  
Lower Income ◽  
Distributional Effects ◽  
Income Groups ◽  
Economic Profile ◽  
Different Levels ◽  
Distributional Impacts

Abstract Background and methods This paper studies distributional effects of public transport (PT) subsidies focusing on the Greater Oslo region. We identify how different PT markets enjoy different levels of subsidies. We describe how subsidies are distributed along PT modes and their respective patronage. This is done by document studies and travel surveys, supplemented by expert inquiries. Results We find that high-income groups, served by regional trains and high-speed crafts, receive large per passenger and per passenger-kilometre subsidy, while lower-income areas, typically served by local and regional buses, metros and local trains, receive lower subsidies per passenger. Peak traffic receives higher subsidies than off-peak traffic. The overall distributional profile is, however, found to be moderately progressive, in particular because of the socio-economic profile of the average PT passenger relative to the population as a whole.

Electric Current Pulse Welding of Titanium with 18-10 Stainless Steel

2009 ◽  
Vol 83-86 ◽  
pp. 1251-1253 ◽  
Author(s):  
E.G. Grigoryev ◽  
V.N. Bazanov
Keyword(s):  
Stainless Steel ◽  
Electric Current ◽  
Current Pulse ◽  
Contact Zone ◽  
Welded Joints ◽  
High Speed ◽  
Welded Joint ◽  
Electric Current Pulse ◽  
Pulse Effect ◽  
Different Thickness

The purpose of the work was to determine the capabilities of the pulse effect of electric current and pressure to produce welded joints of various component parts of different thickness from 18-10 stainless steel and titanium. Application of electric current pulses on the surfaces of contacting metallic conductors leads to considerable changes in the surface structure. Depending on the initial state of the surfaces and parameters of the pulse effect this can result in melting without formation of joints, formation of a strong welded joint with characteristics no worse than those of welded metals, and in destruction of the contact zone. A combination of a short electric pulse with simultaneous application of mechanical pressure in the weld zone causes high-speed deformation of the contact zone. The process of joint formation itself does not cause any appreciable diffusion during welding. The greatest energy emission and the maximal heating occur on the contacting surfaces being welded with the passage of an electric current pulse through the welding zone. Simultaneously with intensive heating, and due to applied pressure, high-speed deformation of materials takes place and a strong welded joint is formed. Optimal parameters for the welding of titanium and 18-10 stainless steel have been determined on the basis of the tests conducted. Investigations into the welding of titanium and 18-10 stainless steel have shown that application of a short electric current pulse and pressure produces stronger welded joints composed of both similar and different metals of considerably different thickness.

Thermo-stress coupling field of friction lining during high-speed slide of wire rope in a mine friction-drive hoist

2011 ◽  
Vol 226 (9) ◽  
pp. 2154-2167 ◽  
Author(s):  
Yu-xing Peng ◽  
Zhen-cai Zhu ◽  
Min-ming Tong ◽  
Guo-an Chen ◽  
Yan-hai Cheng ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Contact Zone ◽  
Constitutive Relation ◽  
High Speed ◽  
Thermomechanical Properties ◽  
Element Analysis ◽  
Coupling Field ◽  
Zone Ii ◽  
Coefficient Of Linear Expansion ◽  
Friction Lining

In order to seek the intrinsic reason for the serious high-speed slide accident in a mine hoist, the thermo-stress coupling field of friction lining was studied during the high-speed slide. First, the helical contact characteristics were analysed. Subsequently, the thermomechanical properties and the dynamic coefficient of linear expansion were studied, and the thermomechanical constitutive relation was obtained. Then, the theoretical model of thermo-stress was established with the consideration of the helical contact characteristics and the thermomechanical constitutive relation. Also, the numerical simulation was performed by the finite element analysis. Finally, the experiment was carried out on a friction tester. It is found that the temperature is the highest at the contact zone II and the friction heat focuses on the contact surface layer. The variation frequency of the stress is 6.98 Hz at 0.5 m/s. Besides, the catastrophe for the strain and coefficient of friction occurs at 3 m/s. The thermo-stress concentration occurs at contact zone II. The experiment results agree with the simulation ones, which validates the theoretical model of thermo-stress.

Research on the delamination wear properties of the pure carbon strip at the high-sliding speed with electric current

2018 ◽  
Vol 70 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Hongjuan Yang ◽  
Lin Fu ◽  
Yanhua Liu ◽  
Weiji Qian ◽  
Bo Hu
Keyword(s):  
Electric Current ◽  
High Speed ◽  
Normal Load ◽  
Copper Wire ◽  
Electrical Current ◽  
Wear Properties ◽  
Sliding Speed ◽  
Content Type ◽  
Delamination Wear ◽  
High Speed Data

Purpose This paper aims to investigate the delamination wear properties of a carbon strip in a carbon strip rubbing against a copper wire at the high-sliding speed (380 km/h) with or without electrical current. Design/methodology/approach The friction and wear properties of a carbon strip in a carbon strip rubbing against a copper wire are tested on the high-speed wear tester whose speed can reach up to 400 km/h. The test data have been collected by the high-speed data collector. The worn surfaces of the carbon strip are observed by the scanning electron microscope. Findings It was found that there was a significant increase of the delamination wear with the decrease of the normal load when the electric current is applied. The size of the flake-like peeling also increases with the decrease of normal load. The delamination wear extends gradually from the edge of the erosion pits to the surrounding area with the decrease of the normal load. However, the delamination wear never appears in the absence of electric current. It is proposed that the decreased normal load and the big electrical current are the major causes of the delamination wear of the carbon strip. Originality value The experimental test at high-sliding speed of 380 km/h was performed for the first time, and the major cause of the delamination was discovered in this paper.

scholarly journals Propellant Combustion Wave Studies by Embedded Thermocouple and Imaging Method at Ambient Pressure

2020 ◽  
Author(s):  
Rakesh Kumar Kalal ◽  
Himanshu Shekhar ◽  
Prashant Sudhir Alegaonkar ◽  
Shrikant Pande
Keyword(s):  
Surface Temperature ◽  
High Speed ◽  
Ambient Pressure ◽  
Combustion Mechanism ◽  
Imaging Method ◽  
Flame Zone ◽  
Sem Images ◽  
Propellant Combustion ◽  
Double Base ◽  
Zone Temperature

This paper discusses the method for propellant combustion studies with embedded thermocouple and imaging method at ambient pressure. In this study, three different propellant compositions are experimentally evaluated for surface temperature, flame zone temperature with embedded thermocouple, and reaction zone thickness with high-speed imaging of propellant during combustion at ambient pressure. Preheat zone and flame zone temperature profiles are recorded with time and surface temperature is determined with available models. Observation of these experiments gives the difference between combustion mechanism of double-base propellant with diethylene glycol dinitrate (DEGDN) and 2,4-dinitrotoluene (DNT), composite propellant (CP) and CP with energetic binder. Scanning electron microscope (SEM) images analysis for pristine and quenched sample is also presented.

scholarly journals The effect of temperature on the physiological condition and growth performance of freshwater eel elver Anguilla bicolor bicolor McClelland, 1844

2018 ◽  
Vol 17 (2) ◽  
pp. 181
Author(s):  
Latifa Fekri ◽  
Ridwan Affandi ◽  
Muhammad Fajar Rahardjo ◽  
Tatag Budiardi ◽  
Charles Parningotan Haratua Simanjuntak ◽  
...  
Keyword(s):  
Growth Performance ◽  
Physiological Condition ◽  
Effect Of Temperature ◽  
Aquatic Animal ◽  
Metabolism Rate ◽  
Randomized Design ◽  
Freshwater Eel ◽  
Survival And Growth ◽  
Physiology Laboratory ◽  
Different Levels

<p align="center"><strong>ABSTRACT</strong></p><p align="center"> </p><p>This study aimed to analyze the effect of water temperature on the physiological condition and growth performance of freshwater eel elver<em> Anguilla bicolor bicolor </em>(McClelland, 1844). This study was conducted in March 2017 at the Physiology Laboratory of Aquatic Animal, Faculty of Fisheries and Marine Sciences, Bogor Agricultural University. The study used a completely randomized design with five different levels of temperature (22<sup>°</sup>C, 24<sup>°</sup>C, 26<sup>°</sup>C, 28<sup>°</sup>C, and 30<sup>°</sup>C) as treatments with two replications. The size of elver was 2‒3 g. Fish were fed with 1 mm pellet containing 45% of protein. The feeding level was 7 % of fish biomass and the feeding frequency was two times a day. The results showed that temperatures range from 24‒30<sup>°</sup>C could be used for freshwater eel elver rearing and 28‒30<sup>°</sup>Cwere the best temperatures to support survival and growth performance of eel elver. A temperature of 24<sup>°</sup>C was the best temperature that could reduce the metabolism rate and did not cause stress on the elver.</p><p> </p><p>Keywords: elver, physiological conditions, growth performance, metabolism, temperature</p><p> </p><p> </p><p align="center"><strong>ABSTRAK</strong></p><p align="center"><strong> </strong></p><p>Penelitian dengan tujuan menganalisis pengaruh suhu terhadap kondisi fisiologis dan kinerja pertumbuhan <em>elver</em> ikan sidat (<em>Anguilla bicolor bicolor</em> McClelland, 1844) telah dilakukan pada bulan Maret 2017 di Laboratorium Fisiologi Hewan Air FPIK IPB. Penelitian menggunakan rancangan acak lengkap dengan lima perlakuan suhu berbeda (22<sup>°</sup>C, 24<sup>°</sup>C, 26<sup>°</sup>C, 28<sup>°</sup>C, dan 30<sup>°</sup>C) dengan masing-masing dua ulangan. Ukuran benih yang digunakan 2‒3 g. Pakan yang diberikan berupa pellet berukuran 1 mm dengan kadar protein 45%. Jumlah pakan yang diberikan (FR) adalah 7% dari biomassa ikan dan diberikan dua kali sehari. Hasil penelitian menunjukkan bahwa kisaran suhu 24‒30<sup>°</sup>C dapat digunakan dalam pemeliharaan <em>elver</em> ikan sidat, dan suhu 28‒30<sup>°</sup>C merupakan suhu yang sangat baik untuk mendukung kelangsungan hidup dan pertumbuhan <em>elver</em> ikan sidat. Suhu media 24<sup>°</sup>C adalah suhu terbaik yang dapat menekan laju metabolisme dengan tidak menyebabkan stres pada <em>elver </em>ikan sidat.</p><p> </p><p>Kata kunci: <em>elver</em>, kondisi fisiologis, kinerja pertumbuhan, metabolisme, suhu</p><p> </p><p> </p>

scholarly journals Improved Loss-of-Lubrication Performance with Lubricants Containing Nano-Graphene Platelets and Ionic Liquids

2020 ◽  
Vol 10 (22) ◽  
pp. 7958
Author(s):  
Nikhil Murthy ◽  
Amarendra K. Rai ◽  
Stephen Berkebile
Keyword(s):  
High Speed ◽  
Operation Time ◽  
Potential Cost ◽  
Lubrication Performance ◽  
Wide Range ◽  
Load Carrying ◽  
Graphene Platelets ◽  
Nano Graphene ◽  
Oil Blend ◽  
Pin On Disk

In this study, nano-graphene platelets (NG) and a phosphonium-phosphate-based ionic liquid (IL) were studied as additives to rotorcraft gearbox oil to improve the resistance to scuffing under starved lubricated conditions. Behavior under a loss of lubrication was evaluated using a high-speed ball-on-disk tribometer and a reciprocating cylindrical pin-on-disk tribometer. In addition, the scuffing load and friction over a wide range of sliding and entrainment speeds was determined. On the high-speed ball-on-disk tribometer, an oil blend containing both NG and IL additives was able to operate two times longer than an unadditivized oil before scuffing after the lubrication supply was removed. The increase in time to scuffing was larger for two additives together than the sum of their parts. The additives showed an increase in scuffing load individually but were detrimental when mixed together with a lower scuffing load. The combination of NG and IL show promise as additives to increase the operation time of gears during loss of lubrication, however at the potential cost of decreasing the load-carrying capacity of the oil.

Effect of temperature, time and glycerol concentration on the dehydration and rehydration process of Steinernema carpocapsae and S. feltiae in alginate granule formulation

Nematology ◽  
2017 ◽  
Vol 19 (2) ◽  
pp. 225-235 ◽  
Author(s):  
Naser Eivazian Kary ◽  
Samira Chahardoli ◽  
Davoud Mohammadi ◽  
Aoife B. Dillon
Keyword(s):  
Survival Rates ◽  
Steinernema Carpocapsae ◽  
Effect Of Temperature ◽  
Glycerol Solution ◽  
Glycerol Concentration ◽  
Granule Formulation ◽  
Osmotic Solution ◽  
Temperature Time ◽  
Rehydration Process ◽  
Different Levels

The osmotic responses ofSteinernema carpocapsaeandS. feltiaein terms of dehydration and rehydration in the presence of calcium alginate and formaldehyde were studied. Infective juveniles (IJ) were exposed to different levels of osmotic concentrations, temperatures and dehydration periods and survival of immobilised IJ was quantified. Osmotic responses showed significant differences and the highest numbers of osmotically dehydratedS. feltiaeandS. carpocapsaeIJ were recorded at 14 and 12% glycerol solution, respectively. Mean percentage of rehydrated IJ was significantly higher when dehydration was processed in 22% glycerol solution. Alginate-formulated IJ showed significantly different survival rates depending on the IJ state (dehydrated or non-dehydrated) and the presence of antimicrobial agent. In addition to optimising alginate formulation, the results demonstrate that the concentration of osmotic solution not only determines the percentage of dehydrated IJ, but also their recovery rate during rehydration. By adding formaldehyde, considerable increases were observed in IJ survival.

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