scholarly journals Basic Research for the Development of Fertiliser Spreaders

2006 ◽  
pp. 52-57
Author(s):  
Zoltán Csizmazia ◽  
Ilona Nagy Polyák ◽  
Attila Kőkuti
Keyword(s):  
Coefficient Of Friction ◽  
Basic Research ◽  
Free Fall ◽  
Aerodynamic Characteristics ◽  
Physical Characteristics ◽  
Wind Tunnels ◽  
Rotating Disks ◽  
The Real ◽  
Aerodynamic Properties ◽  
The Coefficient Of Friction

The knowledge of the physical characteristics of fertiliser particles is essential for the constructors and operators of fertiliser distributors. Among physical characteristics, the most important are the frictional and aerodynamic properties for the description of particle movement. Adjustable angled slopes, shearing boxes and various rotating disks are used to identify frictional properties. We have developed a high precision shearing box with digital force measuring cells and a distance signaller (incremental transducer) that we use for slide tests efficiently. We measured the frictional characteristics of 6 different fertilisers: the inner coefficient of friction and the coefficient of friction on ten test surfaces most commonly used in machinery, and we specified the relationship between displacement, loading and the coefficient of friction. We can conclude that the material of the frictional surface significantly influences the force of friction.However, our experience tells us that the shearing box is not suitable for the measurement of the inner friction, since the examined particles slide on the metal surface of the shearing box in a growing extent in the course of displacement, so it does not measure the real inner friction. Therefore, in our experiment we have developed rotating shearing equipment with a constant shearing surface to identify the inner friction. We tested the equipment with fertilisers and we identified the inner frictional characteristics of 6 different fertilisers. With the developed rotating shearing apparatus we could measure the real inner friction of the particles.To identify the aerodynamic characteristics of granules, wind tunnels and free-fall tests are used. An elutriator have been developed for our investigation. We have used fertilisers for testing the measuring equipment and we have identified the aerodynamic characteristics of 6 different fertilisers.

The study of Rockfall in Keelung Mountain Area of Northeastern Taiwan

2020 ◽  
Author(s):  
Bo Xu
Keyword(s):  
Coefficient Of Friction ◽  
Incident Angle ◽  
Free Fall ◽  
Coefficient Of Restitution ◽  
Movement Trajectory ◽  
Slope Surface ◽  
Mountain Area ◽  
Geological Materials ◽  
The Coefficient Of Friction ◽  
Rockfall Hazards

<p>This study focued on the case of rockfall in the Keelung Mountain Area in the northeastern part of Taiwan. To explore the different trajectories and range including free fall, bouncing and rolling when the rocks fall down, this research tried to analyze the local geomorphological characteristics, distribution of geological materials, and the extension of the discontinuities.</p><p>In the results, "coefficient of restitution " and "coefficient of friction" are the most important factors which affect the movement trajectory of bouncing and rolling. The coefficient of restitution is mainly affected by the three factors, such as the strength of slope surface’s material, incident angle, and collision speed. In the situation when falling rocks descend from 2m height, and setting the incident angles as 30°, 45°and 60°, we observed the coefficient of normal restitution as 0.18, 0.12, and 0.10. These results showed that, the coefficient of normal restitution of the rockfall inversely decreased with the incident angle. When fixing the incident angle at 90°, the coefficients of restitution were observed as 0.41, 0.35, and 0.31 when the rockfall from 1 m, 2 m, 3 m. This research found that the coefficient of restitution inversely decreased with the collision speed of rockfall. The size of the falling rocks which was related to the size of the block on the slope, also affected the path of the rockfall based on the bouncing movement. When the size of the rock was smaller than the size of the block at the bottom of the slope, the trajectories were influenced by undulation. When the size of the rock was larger than deposited one, the rock was hard to be affected by slope fluctuation, and continue to keep scrolling. At this situation, the movement of the rockfall was mainly affected by the coefficient of friction rather than the coefficient of restitution’s impact. The simulation is carried out using the Rocscience Rocfall program, which depicts the path and energy of rockfall, these data can be used as important reference basis of prevention of rockfall hazards.</p><p>Keywords: Rockfall, Coefficient of Restitution, Coefficient of Friction, Free Fall, Bouncing , Rolling</p>

scholarly journals Influence of WS2 Nanoparticles Lubricants on Physical Characteristics of Wrought Aluminium Alloys

2019 ◽  
pp. 1240-1250
Author(s):  
Riyadh A. Al-Samarai ◽  
Amjed Saleh Mahmood ◽  
Omar M. Ahmed
Keyword(s):  
Wear Rate ◽  
Coefficient Of Friction ◽  
Wear Mechanisms ◽  
Aluminium Alloys ◽  
Loss Rate ◽  
Physical Characteristics ◽  
Oxidative Wear ◽  
Pin On Disc ◽  
The Coefficient Of Friction ◽  
Aisi 1045

The present study considers an influence of WS2 nanoparticles lubricants on physical characteristics of wrought Aluminium alloys. It is investigated parameters-performance relationship via tribological pin-on-disc tests, the pin is made of Aluminium alloys and the disk is made of AISI.1045, and the humidity was 70%. Oils with WS2 nanoparticles and without them reveal the loss rate of wear. In this study, the coefficient of friction (CoF) is reduced from 0.27 to 0.22 and the wear rate decreased from 0.128 x 10-6 Nm-1 to 0.107 x 10-6 Nm-1 at a load of 20 N. All worn surfaces were typically three types in wear mechanisms such as adhesive, abrasive, and oxidative wear. In addition, the use of nanoparticle enhanced the viscosity. This study showed promising results and concluded that the wrought Aluminium alloy to be the superior with WS2 nanoparticles, Furthermore, the wear rate has been reduced of 14% comparison without the use of WS2.

Observation of Water Behavior in the Contact Area between Porous Rubber and a Mating Surface during Sliding

2012 ◽  
Vol 40 (3) ◽  
pp. 186-200
Author(s):  
Yusuke Minami ◽  
Tomoaki Iwai ◽  
Yutaka Shoukaku
Keyword(s):  
Water Flow ◽  
Coefficient Of Friction ◽  
Contact Area ◽  
Real Contact Area ◽  
The Real ◽  
Air Bubble ◽  
Real Contact ◽  
Rear Edge ◽  
The Coefficient Of Friction ◽  
Dove Prism

ABSTRACT Porous rubber is often used as the tread rubber of studless tires because of its higher coefficient of friction on icy surfaces, as the real contact area is larger because of its lower elastic modulus. It is said that the real contact area increases owing to the water absorption into the pores. The purpose of this study was to clarify the effect of pores on the surface of porous rubber during sliding under wet conditions. In this experiment, porous rubber was rubbed with a dove prism under wet conditions, so as to measure the coefficient of friction in concurrence with observing the friction surface. The total internal reflection method was adopted to distinguish the real contact area from the wet contact area. The real contact area was observed as a black area in captured image. Particle-tracking velocimetry was also conducted to visualize the water flow in the vicinity of pores during the sliding. The results of this study show that the absorption of water into the pores was not observed. The pore contained an air bubble during the sliding. The water flow detouring around the air bubble in the pore was also observed. In regard to contact, the front edge of the pore was not in contact with the mating dove prism. On the other hand, the rear edge of the pore was clearly seen as a black arc even if the pore left the dove prism. Thus, the rear edge of the pore contacting with the dove prism most likely wipes the water, so that the coefficient of friction of rubber with the pore was higher than that without the pore.

The Effects of Relative Angular Motions on Friction at Rough Planar Contacts

1993 ◽  
Vol 115 (1) ◽  
pp. 96-101 ◽  
Author(s):  
D. P. Hess ◽  
A. Soom
Keyword(s):  
Rough Surface ◽  
Friction Force ◽  
Contact Force ◽  
Coefficient Of Friction ◽  
Angular Displacement ◽  
Normal Contact ◽  
Normal Contact Force ◽  
The Real ◽  
The Coefficient Of Friction ◽  
Real Area

Changes in friction due to angular motions at rough planar contacts are investigated using a compliant contact model that isolates an angular degree-of-freedom. Expressions are developed that relate the real area of contact, the contact forces and the line-of-action of the resultant normal contact force to the angular displacement for both periodic and random rough surfaces. We assume that the friction force is proportional to the real area of (elastic) contact. For a periodic rough surface, consisting of an array of hemispherical asperities of equal height and radius, the friction force is shown to be independent of angular displacement. The normal force increases and its line-of-action shifts away from the center of the contact as angular displacements increase. Therefore, the coefficient of friction decreases with angular displacement. In contrast, for a randomly rough surface, the contact area and normal contact force are shown to be non-linearly dependent on angular displacement, but remain proportional to each other in the presence of relative angular motion. Therefore, for the randomly rough surfaces the coefficient of friction is independent of angular motion.

Experimental Investigation of aluminum doping crumb rubber/epoxy composite in reciprocating motion

2015 ◽  
Vol 3 ◽  
pp. 1
Author(s):  
Goutam Chandra Karar ◽  
Nipu Modak
Keyword(s):  
Experimental Investigation ◽  
Coefficient Of Friction ◽  
Epoxy Composite ◽  
Normal Load ◽  
Crumb Rubber ◽  
The Other ◽  
Reciprocating Motion ◽  
Molding Process ◽  
Friction Tester ◽  
The Coefficient Of Friction

The experimental investigation of reciprocating motion between the aluminum doped crumb rubber /epoxy composite and the steel ball has been carried out under Reciprocating Friction Tester, TR-282 to study the wear and coefficient of frictions using different normal loads (0.4Kg, 0.7Kgand1Kg), differentfrequencies (10Hz, 25Hz and 40Hz).The wear is a function of normal load, reciprocating frequency, reciprocating duration and the composition of the material. The percentage of aluminum presents in the composite changesbut the other components remain the same.The four types of composites are fabricated by compression molding process having 0%, 10%, 20% and 30% Al. The effect of different parameters such as normal load, reciprocating frequency and percentage of aluminum has been studied. It is observed that the wear and coefficient of friction is influenced by the parameters. The tendency of wear goes on decreasing with the increase of normal load and it is minimum for a composite having 10%aluminum at a normal load of 0.7Kg and then goes on increasing at higher loads for all types of composite due to the adhesive nature of the composite. The coefficient of friction goes on decreasing with increasing normal loads due to the formation of thin film as an effect of heat generation with normal load.

scholarly journals Tribological Aspects, Optimization and Analysis of Cu-B-CrC Composites Fabricated by Powder Metallurgy

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4217
Author(s):  
Üsame Ali Usca ◽  
Mahir Uzun ◽  
Mustafa Kuntoğlu ◽  
Serhat Şap ◽  
Khaled Giasin ◽  
...  
Keyword(s):  
Weight Loss ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Applied Load ◽  
Practical Significance ◽  
Tribological Characteristics ◽  
M 10 ◽  
Wide Range ◽  
The Coefficient Of Friction ◽  
Four Levels

Tribological properties of engineering components are a key issue due to their effect on the operational performance factors such as wear, surface characteristics, service life and in situ behavior. Thus, for better component quality, process parameters have major importance, especially for metal matrix composites (MMCs), which are a special class of materials used in a wide range of engineering applications including but not limited to structural, automotive and aeronautics. This paper deals with the tribological behavior of Cu-B-CrC composites (Cu-main matrix, B-CrC-reinforcement by 0, 2.5, 5 and 7.5 wt.%). The tribological characteristics investigated in this study are the coefficient of friction, wear rate and weight loss. For this purpose, four levels of sliding distance (1000, 1500, 2000 and 2500 m) and four levels of applied load (10, 15, 20 and 25 N) were used. In addition, two levels of sliding velocity (1 and 1.5 m/s), two levels of sintering time (1 and 2 h) and two sintering temperatures (1000 and 1050 °C) were used. Taguchi’s L16 orthogonal array was used to statistically analyze the aforementioned input parameters and to determine their best levels which give the desired values for the analyzed tribological characteristics. The results were analyzed by statistical analysis, optimization and 3D surface plots. Accordingly, it was determined that the most effective factor for wear rate, weight loss and friction coefficients is the contribution rate. According to signal-to-noise ratios, optimum solutions can be sorted as: the highest levels of parameters except for applied load and reinforcement ratio (2500 m, 10 N, 1.5 m/s, 2 h, 1050 °C and 0 wt.%) for wear rate, certain levels of all parameters (1000 m, 10 N, 1.5 m/s, 2 h, 1050 °C and 2.5 wt.%) for weight loss and 1000 m, 15 N, 1 m/s, 1 h, 1000 °C and 0 wt.% for the coefficient of friction. The comprehensive analysis of findings has practical significance and provides valuable information for a composite material from the production phase to the actual working conditions.

scholarly journals Influence of Beam Power on Young’s Modulus and Friction Coefficient of Ti–Ta Alloys Formed by Electron-Beam Surface Alloying

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1246
Author(s):  
Stefan Valkov ◽  
Dimitar Dechev ◽  
Nikolay Ivanov ◽  
Ruslan Bezdushnyi ◽  
Maria Ormanova ◽  
...  
Keyword(s):  
Electron Beam ◽  
Young’S Modulus ◽  
Coefficient Of Friction ◽  
Young's Modulus ◽  
Beam Power ◽  
Surface Alloying ◽  
Surface Alloys ◽  
X Ray ◽  
The Coefficient Of Friction ◽  
Beam Surface

In this study, we present the results of Young’s modulus and coefficient of friction (COF) of Ti–Ta surface alloys formed by electron-beam surface alloying by a scanning electron beam. Ta films were deposited on the top of Ti substrates, and the specimens were then electron-beam surface alloyed, where the beam power was varied from 750 to 1750 W. The structure of the samples was characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Young’s modulus was studied by a nanoindentation test. The coefficient of friction was studied by a micromechanical wear experiment. It was found that at 750 W, the Ta film remained undissolved on the top of the Ti, and no alloyed zone was observed. By an increase in the beam power to 1250 and 1750 W, a distinguished alloyed zone is formed, where it is much thicker in the case of 1750 W. The structure of the obtained surface alloys is in the form of double-phase α’and β. In both surface alloys formed by a beam power of 1250 and 1750 W, respectively, Young’s modulus decreases about two times due to different reasons: in the case of alloying by 1250 W, the observed drop is attributed to the larger amount of the β phase, while at 1750 W is it due to the weaker binding forces between the atoms. The results obtained for the COF show that the formation of the Ti–Ta surface alloy on the top of Ti substrate leads to a decrease in the coefficient of friction, where the effect is more pronounced in the case of the formation of Ti–Ta surface alloys by a beam power of 1250 W.

Reducing the Coefficient of Friction for Fast-Absorbing Gut Suture

2009 ◽  
Vol 35 (12) ◽  
pp. 2004 ◽  
Author(s):  
Jonathan Lee Bingham ◽  
Mariah R. Brown ◽  
Julian Ramsey Mellette
Keyword(s):  
Coefficient Of Friction ◽  
The Coefficient Of Friction
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