Wear particle

The neuropeptide calcitonin gene-related peptide (CGRP) has been described to have an inhibitory effect on endotoxin- and wear particle-induced inflammation in the early stages of periprosthetic osteolysis.

12p vioregon2711 22-02-2021 5 1   Download

Aseptic loosening is a significant impediment to joint implant longevity. Prosthetic wear particles are postulated to play a central role in the onset and progression of periprosthetic osteolysis, leading to aseptic loosening of the prosthesis.

10p vitennessee2711 02-02-2021 7 1   Download

The surface modification of engineering materials by laser beam scanning (LBS) allows the improvement of properties in terms of reduced wear, increased corrosion resistance, and better strength. In this study, the laser beam scan method was applied to produce an oxide dispersion strengthened (ODS) structure on a zirconium metal surface. A recrystallized Zircaloy-4 alloy sheet with a thickness of 2 mm, and Y2O3 particles of 10 μm were selected for ODS treatment using LBS.

8p minhxaminhyeu5 30-06-2019 20 0   Download

Some types of PPE are simply not appropriate for use in certain situations. For instance, let's say you have maintenance employees working in a shop area where they have been assigned to wear ANSI-approved safety glasses with side shields for protection against flying particles generated at various grinding machines. One of these employees is called away to work in a treating area where dip tanks are located. Assigned PPE in the treating area consists of chemical-protective splash goggles.

5p docvachiase 03-05-2013 41 7   Download

Shielding gloves and sleeves containing up to 0.33 mmPb are manufactured. Like aprons, they are ineffective shields against most radiations other than electrons (beta particles) and low energy scattered X rays. Wearing the gloves reduces dexterity and consequently, if used inappropri- ately, will result in significant hand doses and greater body doses by prolonging the exposure. The sleeves are flexible and, when used as local shielding, provide good cover for the extremities.

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Compressor valves can become distorted and fractured if liquid refrigerant is allowed to enter the cylinder; this is known as liquid slugging. For this reason service cylinders should never be inverted during the low side charging of a system. Valve seats and reeds can become pitted if metal filings or small particles of grit are allowed to enter pipework during installation or repairs. They may circulate with the refrigerant and become trapped between the reeds and valve seats when compression takes place.

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The larger, so-called "coarse" particles are mostly produced by mechanical processes, such as automobile tire wear on the road, industrial cutting, grinding and pulverizing processes and re-suspension of particles from the ground or other surfaces by wind and human activities. The chemical composition of coarse particles may be somewhat similar to the chemical composition of soil in that area, along with industrial compounds from activities such as mining or smelting operations.

13p doipassword 01-02-2013 39 3   Download

The movement of vehicles on the street also results in resuspension of road dust. Emissions also occur as a result of tyre wear and brake lining wear. Although there is a lack of data, it is expected that most of these particles will be in the size range 3 to some 30µm. The chemical composition of these particles may also be very different from those derived from combustion. The road dust deposit available for resuspension comes from mechanical wear of, and dirt on, vehicles (incl. tyre and brake lining wear), debris from loads on vehicles, influx of soil material etc.

50p saimatkhauroi 01-02-2013 51 5   Download

Particulate emissions from road transport arise as direct emissions from vehicle exhausts, tyre and brake wear and resuspension of road dust. In urban areas, emissions from road transport are thought to be the major source of PM10. In general, diesel engine vehicles emit a greater mass of fine particulate matter, per vehicle, than petrol engines. Diesel emissions are mainly composed of soot particles, volatile hydrocarbons and some sulphate from the fuel sulphur.

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In order to be suitable for tribological applications, polymeric materials, which can usually exhibit mechanical strength, lightness, ease of processing, versatility and low cost, together with acceptable thermal and environmental resistances, have to show good abrasion and wear resistance. This target is not easy to achieve, since the viscoelasticity of polymeric materials makes the analysis of the tribological features and the processes involved in such phenomena quite complicated.

0p orchid_1 25-09-2012 70 13   Download

Wear Film failure impairs the relative movement between solid bodies and inevitably causes severe damage to the contacting surfaces. The consequence of film failure is severe wear. Wear in these circumstances is the result of adhesion between contacting bodies and is termed ‘adhesive wear’. When the intervening films are partially effective then milder forms of wear occur and these are often initiated by fatigue processes due to repetitive stresses under either sliding or rolling. These milder forms of wear can therefore be termed ‘fatigue wear’.

20p hiruscar 13-10-2010 47 4   Download

where V is the volume worn away, W is the normal load, x is the sliding distance, H is the hardness of the surface being worn away, and k is a nondimensional wear coefficient dependent on the materials in contact and their exact degree of cleanliness. The term k is usually interpreted as the probability that a wear particle is formed at a given asperity encounter. Equation (21.5) suggests that the probability of a wear-particle formation increases with an increase in the real area of contact, Ar (Ar = W=H for plastic contacts), and the sliding distance. ...

20p lyacau 30-12-2009 66 4   Download