Dating of Impact Events

1998 ◽  
pp. 157-183 ◽  
Author(s):  
Urs Schärer
Keyword(s):  
Impact Events

scholarly journals Algorithmic Pricing and Price Gouging. Consequences of High-Impact, Low Probability Events

2021 ◽  
Vol 13 (5) ◽  
pp. 2542
Author(s):  
Juan Manuel Sánchez-Cartas ◽  
Alberto Tejero ◽  
Gonzalo León
Keyword(s):  
Algorithm Design ◽  
High Impact ◽  
Design Features ◽  
Market Conditions ◽  
External Market ◽  
Contestable Markets ◽  
Terror Attacks ◽  
Low Probability ◽  
Price Gouging ◽  
Impact Events

Algorithmic pricing may lead to more efficient and contestable markets, but high-impact, low-probability events such as terror attacks or heavy storms may lead to price gouging, which may trigger injunctions or get sellers banned from platforms such as Amazon or eBay. This work addresses how such events may impact prices when set by an algorithm and how different markets may be affected. We analyze how to mitigate these high-impact events by paying attention to external (market conditions) and internal (algorithm design) features surrounding the algorithms. We find that both forces may help in partially mitigating price gouging, but it remains unknown which forces or features may lead to complete mitigation.

scholarly journals Protective Capacity of Ice Hockey Helmets against Different Impact Events

2016 ◽  
Vol 44 (12) ◽  
pp. 3693-3704 ◽  
Author(s):  
J. Michio Clark ◽  
Andrew Post ◽  
T. Blaine Hoshizaki ◽  
Michael D. Gilchrist
Keyword(s):  
Ice Hockey ◽  
Protective Capacity ◽  
Impact Events

A hybrid model of the CO 2 geochemical cycle and its application to large impact events

1986 ◽  
Vol 286 (5) ◽  
pp. 361-389 ◽  
Author(s):  
J. F. Kasting ◽  
S. M. Richardson ◽  
J. B. Pollack ◽  
O. B. Toon
Keyword(s):  
Hybrid Model ◽  
Large Impact ◽  
Geochemical Cycle ◽  
Impact Events

Low Velocity Impact Resistance of CPVC Pipes Exposed to Natural Outdoor Weathering Conditions

2012 ◽  
Vol 445 ◽  
pp. 959-964
Author(s):  
Z. Khan ◽  
Necar Merah ◽  
A. Bazoune ◽  
S. Furquan
Keyword(s):  
Impact Resistance ◽  
Outdoor Exposure ◽  
Impact Testing ◽  
Low Velocity Impact ◽  
Pipe Material ◽  
Low Velocity ◽  
Impact Energies ◽  
The Impact ◽  
Impact Events ◽  
Outdoor Weathering

Low velocity drop weight impact testing of CPVC pipes was conducted on 160 mm long pipe sections obtained from 4-inch (100 mm) diameter schedule 80 pipes. Impact test were carried out for the base (as received) pipes and after their exposure to out door natural weathering conditions in Dhahran, Saudi Arabia. The results of the impact testing on the natural (outdoor exposure) broadly suggest that the natural outdoor exposures produce no change in the impact resistance of CPVC pipe material for the impact events carrying low incident energies of 10 and 20J. At the impact energies of 35 and 50J the natural outdoor exposures appear to cause appreciable degradation in the impact resistance of the CPVC pipe material. This degradation is noted only for the longer exposure periods of 12 and 18 months.

scholarly journals LABORATORY OBSERVATIONS OF IMPACTS ON COARSE SEDIMENT BEACHES

2011 ◽  
Vol 1 (32) ◽  
pp. 53
Author(s):  
Ian Ball ◽  
Edgar Mendoza-Baldwin ◽  
David Simmonds ◽  
Adrián Pedrozo-Acuña ◽  
Dominic E Reeve
Keyword(s):  
Full Scale ◽  
Impact Pressure ◽  
Coarse Grained ◽  
Laboratory Measurements ◽  
Coarse Sediment ◽  
Full Scale Tests ◽  
The Impact ◽  
Impact Events ◽  
Plunging Breaker

In this paper we present laboratory observations of plunging wave breaker impact pressure responses on a steep coarse-grained beach, extending previous work conducted by Pedrozo-Acuña et al. (2008). Scale laboratory measurements of plunging breaker impact events are reported and compared with the previous full-scale tests. These tests extend the previous relationships to a wider range of surf-similarity parameters and indicate a continued reduction in impact pressure as the transition from plunging impacts to surging impacts is approached. Additional results from scale tests conducted on a smooth impermeable slope also indicate the presence of a maximum impact pressure within the plunging breaker region; however also suggest it may be necessary to include roughness and permeability in the parameterization of the impact pressure.

40 Ar— 39 Ar ages and irradiation history of Luna 24 basalts

1980 ◽  
Vol 297 (1428) ◽  
pp. 27-39 ◽  
Keyword(s):  
Solar Wind ◽  
High Temperature ◽  
Production Rate ◽  
Cosmic Ray ◽  
Spectral Information ◽  
Near Surface ◽  
Surface Sample ◽  
History Of ◽  
Impact Events ◽  
The Way

The Luna 24 mission sampled a variety of lithologies in a single core. Two of these lithologies, a metabasalt (24196) and a crushed basalt (24170) have been subjected to 40 Ar- 39 Ar dating experiments to determine if metamorphism significantly post-dated basalt extrusion. The metabasalt exhibited symptoms of both solar wind contamination and 39 Ar recoil; in view of these effects an age may only be defined by making extreme assumptions. High temperature release fractions give an age of 3.36 ± 0.11 Ga, while the cumulate 40 Ar/ 39 Ar ratio gives 3.14 ± 0.16 Ga; both are comparable with the basalt (24170) age and suggest that the metabasalts represent thermally penecontemporaneously metamorphosed flow margins, rather than the products of later impact events. The feldspar from the microgabbro yielded an age of 3.37 ± 0.20 Ga. The ratios of cosmogenic 38 Ar to Ca in pyroxene and feldspar are within error identical, indicating that 38 Ar production from Fe in the pyroxene is small. This is the first definitive use of Fe-produced 38 Ar as a spectral hardness indicator and implies that the microgabbro received much of its cosmic ray exposure at depth in the regolith. By taking account of the dependence of 38 Ar production rate with depth it is inferred that the microgabbro layer was deposited within the last 350-500 Ma. By implication, the regolith layers above the microgabbro at the Luna 24 site are younger. The metabasalt has an identical cosmogenic 38 Ar/Ca ratio; however, because of the decrease of production rate with depth it could have experienced a 20 % pre-exposure before deposition of the microgabbro. Spectral information has also been obtained from a reappraisal of published argon data and indicates a much harder spectrum for a near surface sample. The way in which the Ca- and Fe-produced 38 Ar e follow the broad trend of the instantaneous production profiles suggests that the regolith at the Luna 24 site has been relatively undisturbed for much of the last 300 Ma.

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