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Centrifuge contributions to cratering technology
Published in W.H. Craig, R.G. James, A.N. Schofield, Centrifuges in Soil Mechanics, 2020
Impact cratering has also been successfully investigated using the centrifuge technique (Schmidt and Holsapple 1978c; Holsapple 1979b; Schmidt et al 1979). Hypervelocity projectile guns have been mounted on the rotor that are capable of velocities up to 7 km/sec at maximum g. These include two different size powder guns and a two-stage light gas gun, all with active velocity monitoring. A recent investigation by Schmidt (1980) produced estimates for the energy of formation for Meteor Crater, Arizozna, which take into account impact velocity as well as impactor properties. In addition, Holsapple (1980) has developed an analytical model based upon centrifuge data that correlates the equivalent depth of burst of impact cratering. Work continues directed at crater scaling relationships for very large impactors with diameters in excess of 10 km (Schmidt and Holsapple 1982; Schmidt 1983).
An Advanced Surface Particle and Molecular Contaminant Identification, Removal, and Collection System
Published in K. L. Mittal, Particles On Surfaces, 2020
Steven P. Hotaling, Deidra A. Dykeman
The symbiotic relationship between the properties of the two AMCC constituents is the way in which the materials work together in the case of a hypervelocity particle impact scenerio, such as in a cryogenic spacecraft application (see micrometeroite crater of Figure 3). In the event of such an impact, the aerogel, if unsupported could fracture. The metal mesh samples tested have shown similiar behavior with the result of creating secondary contaminants for the system. This effect is obviated by the AMCC in that, the thick aerogel covering on the metal mesh ligaments will slow the incoming projectile and absorb some of the impact, thus decreasing the probability of mesh ligament ablation. In the event of ablation, the thickness of the AMCC heterostructure serves to collect and contain secondary and higher order debris.
Nanotwinning and Directed Alloying to Enhance the Strength and Ductility of Superhard Materials
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Yidi Shen, Qi An, Xiaokun Yang, William A. Goddard III
Superhard materials, such as boron carbide (B4C), boron suboxide (B6O), boron subphosphide (B12P2), and related materials, have been examined extensively using both theory and experiments because of unique properties such as low density, superhardness, high chemical inertness, and resistance to wear.13–16 The combination of these properties makes them excellent candidates for engineering applications such as cutting tools, body armors for soldiers, and additives in manufacturing process. However, their low fracture toughness prevents their extended engineering applications. In particular, B4C exhibits anomalous brittle failure when subjected to hypervelocity impact.17,18
Discharge and electromagnetic radiation behind the hole of simulated charging satellite surface under impact
Published in Waves in Random and Complex Media, 2022
Enling Tang, Liangliang Zhao, Yafei Han, Chuang Chen, Mengzhou Chang
When the projectile hypervelocity impacts the target plate, the material of the projectile and the target plate melts, vaporizes and ionizes under the strong impact. The hot mixture of neutrals, ions and electrons in the impact crater has a high density in the initial moments, which is close to that of a solid material [38]. Because the impact plasma has the characteristics of high density in the initial stage, the probability of collision between the neutrals, ions and electrons in the plasma is very high, which may not meet the definition of standard plasma [39], which is usually called non-ideal plasma. The density gradient diffusing from high density to free interface drives the expansion of non ideal plasma, and the plasma reaches a dynamic equilibrium state. At this moment, the plasma is like the state of magnetic fluid, and its behavior is dominated by electrostatic forces. As the plasma continues to expand, the interaction force between particles can be ignored untimely. The plasma enters single particle motion stage, where the trajectory of each particle is independent and mainly influenced by the external electric field.
Optical emission generated by particle impact during aerosol deposition of alumina films
Published in Journal of Asian Ceramic Societies, 2022
Yasuhito Matsubayashi, Tsuyohito Ito, Kentaro Shinoda, Kazuo Terashima, Jun Akedo
In astronautics, a similar type of particle impact is called hypervelocity impact, which simulates the collision between a spacecraft and space debris or meteoroids [53]. Hypervelocity impact with velocities on the order of tens of kilometers per second generates plasmas [53]. These plasmas are generated by the vaporization and ionization of the target substrates driven by shockwaves [54]. In our system, no optical emission from the substrate was observed, and the gas temperatures remained around room temperature. Furthermore, the particle velocity has been reported to be on the order of 102 m s−1 [41], which is much lower than that of hypervelocity impact experiments. Therefore, the generation mechanism of the discharges in this study was different from that of hypervelocity impact. The discharges and optical emission associated with the particle motion have been observed in various phenomena, such as volcanic lightning [24,25]. Our simple, continuous generation of particle impact discharge may provide a useful experimental platform for understanding this type of discharge.
Impact properties of thermoplastic composites
Published in Textile Progress, 2018
Ganesh Jogur, Ashraf Nawaz Khan, Apurba Das, Puneet Mahajan, R. Alagirusamy
In general, impact phenomena are classified as follows:Low-velocity impact (<11 m/s), which occur through damage from dropped tools, cargo containers, service trucks during maintenance services.High-velocity impact (>11 m/s) damage results by sources like debris from the runway hitting the fuselage during take-off and landing, ice from propellers striking fuselage, hail, and bird strikes.Ballistic impact (>500 m/s). Damage due to ballistic impact is usually related to military applications.Hypervelocity damage (>2000 m/s) is what happens when space debris hits spacecraft.