The number distributions of the brake abrasion dusts had a peak at Dp values of 1 and 2 μm this peak shifted to the coarse side with an increase in the disk temperature. Simultaneously, the abrasion dusts were also collected based on their size by using an Andersen low-volume sampler, and the concentrations of metallic elements (K, Ti, Fe, Cu, Zn, Sb and Ba) in the size-classified dusts were measured by ICP-AES and ICP-MS. The number concentration of the abrasion dusts and their aerodynamic diameters ( Dp) were measured by using an aerodynamic particle sizer (APS) spectrometer with high temporal and size resolution. Iijima, Akihiro Sato, Keiichi Yano, Kiyoko Tago, Hiroshi Kato, Masahiko Kimura, Hirokazu Furuta, NaokiĪbrasion dusts from three types of commercially available non-steel brake pads were generated by a brake dynamometer at disk temperatures of 200, 300 and 400 Â☌.
Particle size and composition distribution analysis of automotive brake abrasion dusts for the evaluation of antimony sources of airborne particulate matter Abrasion was dominated by the alumina and the simulants were only similar to the silica (i.e., sand) on the softer materials of The measured mass loss from each specimen was converted using standard densities to determine total wear volume in cm3. Abrasives included lunar mare simulant JSC- 1A-F (nominal size distribution), sieved JSC-1A-F (<25 m particle diameter), lunar highland simulant NU-LHT-2M, alumina (average diameter of 50 m used per ASTM G76), and silica (50/70 mesh used per ASTM G65). Abraded material specimens included poly(methyl methacrylate) (PMMA), hardened 1045 steel, 6061-T6 aluminum (Al) and 1018 steel. All tests were run under identical conditions. The test methodology is based on ASTM International (ASTM) B611, except it does not mix water with the abrasive. The work discussed in this paper describes the three-body hardware setup consisting of a rotating rubber wheel that applies a load on a specimen as a loose abrasive is fed into the system. For these tests, a new tribotester was developed to expose samples to a variety of industrial abrasives and lunar simulants. Subsequent efforts described in the paper involved three-body abrasion testing designed to be more representative of actual lunar interactions. These simple and robust tests were used to establish standardized measurement techniques for quantifying controlled volumetric wear. Two-body scratch tests were initially performed to examine fundamental interactions of a single particle on a flat surface.
#BITLIFE SIMULATOR HAY FEVER SERIES#
To avoid reoccurrence of these unexpected detrimental equipment problems on future missions to the Moon, a series of two- and three-body abrasion tests were developed and conducted in order to begin rigorously characterizing the effect of lunar dust abrasiveness on candidate surface system materials. Numerous unexpected operational issues relating to the abrasive nature of lunar dust, such as scratched visors and spacesuit pressure seal leaks, were encountered during the Apollo missions. Three-Body Abrasion Testing Using Lunar Dust Simulants to Evaluate Surface System Materials Of these, the Orthofabric suffered the least wear, with both Vectran and Kevlar suffering considerably more extensive filament breakage. The woven structures were all abraded where the top of the weave was struck by the abrasive. This was thought to be due in large part to its non-woven paper structure. The least abrasive damage was suffered by the Tyvek. In the case of Tyvek, the paper structure was dense enough to block dust transport. In the cases of Kevlar and Orthofabric this was accomplished by the addition of a silicone layer. Three of the four new candidate fabrics (all but Vectran) were effective at keeping the dust from penetrating to layers beneath. This protocol was then applied to four materials (Kevlar (DuPont), Vectran (Kuraray Co., Ltd.), Orthofabric, and Tyvek (DuPont)) that are candidates for advanced spacesuits. Sheehy, Brennan H.Ī protocol has been developed that produced the type of lunar soil abrasion damage observed on Apollo spacesuits. Abrasion of Candidate Spacesuit Fabrics by Simulated Lunar Dust
0 kommentar(er)
