scholarly journals Limits on methane release and generation via hypervelocity impact of Martian analogue materials

2013 ◽  
Vol 13 (2) ◽  
pp. 132-140 ◽  
Author(s):  
M. C. Price ◽  
N. K. Ramkissoon ◽  
S. McMahon ◽  
K. Miljković ◽  
J. Parnell ◽  
...  
Keyword(s):  
Hypervelocity Impact ◽  
Potential Mechanism ◽  
Mars Atmosphere ◽  
Water Ice ◽  
Methane Release ◽  
Basaltic Rocks ◽  
Background Levels ◽  
The Impact ◽  
Impact Events ◽  
Insight Into

AbstractThe quantity of methane in Mars' atmosphere, and the potential mechanism(s) responsible for its production, are still unknown. In order to test viable, abiotic, methangenic processes, we experimentally investigated two possible impact mechanisms for generating methane. In the first suite of experiments, basaltic rocks were impacted at 5 km s−1 and the quantity of gases (CH4, H2, He, N2, O2, Ar and CO2) released by the impacts was measured. In the second suite of experiments, a mixture of water ice, CO2 ice and anhydrous olivine grains was impacted to see if the shock induced rapid serpentinization of the olivine, and thus production of methane. The results of both suites of experiments demonstrate that impacts (at scales achievable in the laboratory) do not give rise to detectably enhanced quantities of methane release above background levels. Supporting hydrocode modelling was also performed to gain insight into the pressures and temperatures occurring during the impact events.

In-situ observation of damage evolution in polycarbonate subjected to hypervelocity impact

2019 ◽  
Author(s):  
Nobuaki Kawai ◽  
Mikio Nagano ◽  
Sunao Hasegawa ◽  
Eiichi Sato
Keyword(s):  
Real Time ◽  
Stress Wave ◽  
Damage Evolution ◽  
Impact Damage ◽  
Hypervelocity Impact ◽  
The Other ◽  
Impact Event ◽  
Real Time Imaging ◽  
The Impact ◽  
Impact Events

Abstract In the fields of space engineering and planetary science, hypervelocity impact phenomena have been studied as they relate to the space debris problem and planetary impact. With regard to hypervelocity-impact-induced damage, many studies focus on the evaluation of impact-damage geometry and morphology, for example, to construct the ballistic limit equations and/or penetrating equations for space structures, and to predict the size and shape of crater and fragments generated by planetary impact [1-4]. While the final state or late stage of an impact event are of primal interest, damage accumulation at early stages affect the overall outcome of the impact event. The understanding of hypervelocity-impact-damage processes lead to improvement of material-response models for hypervelocity impact and higher fidelity simulations of hypervelocity impact events. Under such a background, we have performed real-time imaging of hypervelocity-impact events on transparent materials to investigate the impact-damage formation and evolution processes [5-7]. In our previous work, the stress-wave-propagation behavior and damage evolution were observed by means of a transmitted light shadowgraph. In these measurements, the shape of the longitudinal-stress-wave front, crater and spall fracture were successfully visualized. On the other hand, these shadowgraph images provide little information about damage microstructure. The shadowgraph has difficulty in visualizing ramped waves, such as the release wave, and also for the shear wave which is not accompanied by the change of volumetric strain. Those play important role in initiating damage. This occurs because the intensity of the shadowgraph image depends on the second spatial derivative of the refractive index. In this study, we try two types of real-time imaging of impact events. One is imaging by using scattered light on the impacted target to visualize the microstructure of the impact-induced damage, the other is a shadowgraph using polarized light to visualize propagation of the impact-induced stress field.

Real Time Measurement of Head Acceleration During Youth Soccer Play

2009 ◽  
Author(s):  
Erin M. Hanlon ◽  
Cynthia A. Bir
Keyword(s):  
Head Acceleration ◽  
Youth Soccer ◽  
Real Time Measurement ◽  
Head Protection ◽  
Bite Plate ◽  
Impact Data ◽  
The Impact ◽  
Impact Events ◽  
Emg Electrodes ◽  
Insight Into

The collection of on-field, head impact data in soccer has been a challenge for researchers. Given the lack of headgear, the ability to instrument players, similar to what has been done in other sports [1, 2], is not possible. [3–5]. Laboratory recreations using reflective targets, EMG electrodes, and an instrumented bite plate have provided some insight into heading impact events [3, 5]. However, all of this instrumentation changes the ability of the player to move freely and, therefore, alters the dynamic of the impact. By developing a wireless acceleration measurement system which does not inhibit movement and provides no head protection, the linear and angular head accelerations can be measured during actual soccer play.

Widespread erosion and mass failure from the ∼51 Ma Montagnais marine bolide impact off southwestern Nova Scotia, Canada 1This article is one of a series of papers published in this CJES Special Issue on the theme of Mesozoic–Cenozoic geology of the Scotian Basin. 2Earth Sciences Sector Contribution 20120241.

2012 ◽  
Vol 49 (12) ◽  
pp. 1567-1594 ◽  
Author(s):  
Mark E. Deptuck ◽  
D. Calvin Campbell
Keyword(s):  
New England ◽  
Outer Shelf ◽  
Stratigraphic Correlation ◽  
Impact Event ◽  
Ground Shaking ◽  
Stratigraphic Subdivision ◽  
The Impact ◽  
Impact Events ◽  
Insight Into ◽  
Upper Slope

The ∼51 Ma Montagnais impact crater on the outer Scotian Shelf is well known, but the potential effects from the impact event on the slope and rise seaward of the crater have, until now, remained poorly understood. Through detailed seismic stratigraphic correlation and ties to available wells, we define a threefold seismic stratigraphic subdivision for Upper Cretaceous to Eocene strata on the shelf and slope, calibrated to the most recent biostratigraphic results. Using this framework, we identify a number of depositional and erosional products that are temporally consistent with a late Ypresian impact event (within the limits of seismic and biostratigraphic resolution). We link a series of prominent failure scarps on the outer shelf and upper slope to a single widespread mass-transport deposit (MTD) on the lower continental slope, rise, and abyssal plain. Failed material amassed in a large debris field referred to here as the “Montagnais MTD”. It covers an area of ∼93 000 km2 and travelled up to 580 km from the impact site where its distal termination onlaps the New England Seamounts, making it one of the largest known debris avalanches on Earth. We interpret these deposits, and the associated pattern of erosion landward of them, as products of widespread margin collapse caused by a combination of ground shaking and ensuing tsunamis triggered by the Montagnais impact event. This study provides insight into the potential effects of outer-shelf marine impact events immediately downslope from impact sites, and their diminished effects with increasing distance along the margin.

scholarly journals Fragmentation of colliding planetesimals with water content

2014 ◽  
Vol 9 (S310) ◽  
pp. 138-141 ◽  
Author(s):  
Thomas I. Maindl ◽  
Rudolf Dvorak ◽  
Christoph Schäfer ◽  
Roland Speith
Keyword(s):  
Brittle Failure ◽  
Escape Velocity ◽  
Small Bodies ◽  
Water Ice ◽  
Hit And Run ◽  
Impact Angles ◽  
The Impact ◽  
Insight Into ◽  
Water Contents ◽  
Asteroid Families

AbstractWe investigate the outcome of collisions of Ceres-sized planetesimals composed of a rocky core and a shell of water ice. These collisions are not only relevant for explaining the formation of planetary embryos in early planetary systems, but also provide insight into the formation of asteroid families and possible water transport via colliding small bodies. Earlier studies show characteristic collision velocities exceeding the bodies' mutual escape velocity which—along with the distribution of the impact angles—cover the collision outcome regimes ‘partial accretion’, ‘erosion’, and ‘hit-and-run’ leading to different expected fragmentation scenarios. Existing collision simulations use bodies composed of strengthless material; we study the distribution of fragments and their water contents considering the full elasto-plastic continuum mechanics equations also including brittle failure and fragmentation.

scholarly journals Changing landscapes: Gay men in the west and northwest of Ireland

Sexualities ◽  
2020 ◽  
pp. 136346072098169
Author(s):  
Aidan McKearney
Keyword(s):  
Gay Men ◽  
Social Rights ◽  
Irish Society ◽  
Recent Past ◽  
Same Sex ◽  
Lgbt People ◽  
The Many ◽  
Northwest Region ◽  
The Impact ◽  
Insight Into

This article focuses on the experiences of gay men in the rural west and northwest region of Ireland, during a period of transformational social and political change in Irish society. These changes have helped facilitate new forms of LGBTQI visibility, and local radicalism in the region. Same-sex weddings, establishment of rural LGBT groups and marching under an LGBT banner at St Patricks Day parades would have been unthinkable in the recent past; but they are now becoming a reality. The men report continuing challenges in their lives as gay men in the nonmetropolitan space, but the emergence of new visibility, voice and cultural acceptance of LGBT people is helping change their lived experiences. The study demonstrates the impact of local activist LGBT citizens. Through their testimonies we can gain an insight into the many, varied and interwoven factors that have interplayed to create the conditions necessary for the men to: increasingly define themselves as gay to greater numbers of people in their localities; to embrace greater visibility and eschew strategies of silence; and aspire to a host of legal, political, cultural and social rights including same-sex marriage. Organic forms of visibility and local radicalism have emerged in the region and through an analysis of their testimonies we can see how the men continue to be transformed by an ever-changing landscape.

Double, triple or quadruple hits? Exploring the impact of cybercrime on victims in the Netherlands

2021 ◽  
pp. 026975802110106
Author(s):  
Raoul Notté ◽  
E.R. Leukfeldt ◽  
Marijke Malsch
Keyword(s):  
Public Opinion ◽  
Literature Review ◽  
The Netherlands ◽  
Public Discourse ◽  
Moral Judgments ◽  
Victim Blaming ◽  
High Prevalence ◽  
Different Types ◽  
The Impact ◽  
Insight Into

This article explores the impact of online crime victimisation. A literature review and 41 interviews – 19 with victims and 22 with experts – were carried out to gain insight into this. The interviews show that most impacts of online offences correspond to the impacts of traditional offline offences. There are also differences with offline crime victimisation. Several forms of impact seem to be specific to victims of online crime: the substantial scale and visibility of victimhood, victimisation that does not stop in time, the interwovenness of online and offline, and victim blaming. Victims suffer from double, triple or even quadruple hits; it is the accumulation of different types of impact, enforced by the limitlessness in time and space, which makes online crime victimisation so extremely invasive. Furthermore, the characteristics of online crime victimisation greatly complicate the fight against and prevention of online crime. Finally, the high prevalence of cybercrime victimisation combined with the severe impact of these crimes seems contradictory with public opinion – and associated moral judgments – on victims. Further research into the dominant public discourse on victimisation and how this affects the functioning of the police and victim support would be valuable.

scholarly journals Using syndromic measures of mortality to capture the dynamics of COVID-19 in Java, Indonesia, in the context of vaccination rollout

BMC Medicine ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Bimandra A. Djaafara ◽  
Charles Whittaker ◽  
Oliver J. Watson ◽  
Robert Verity ◽  
Nicholas F. Brazeau ◽  
...  
Keyword(s):  
Rural Areas ◽  
Vaccination Campaign ◽  
Control Measures ◽  
Additional Insight ◽  
Short Term ◽  
If Current ◽  
Vaccine Impact ◽  
Potential Impact ◽  
The Impact ◽  
Insight Into

Abstract Background As in many countries, quantifying COVID-19 spread in Indonesia remains challenging due to testing limitations. In Java, non-pharmaceutical interventions (NPIs) were implemented throughout 2020. However, as a vaccination campaign launches, cases and deaths are rising across the island. Methods We used modelling to explore the extent to which data on burials in Jakarta using strict COVID-19 protocols (C19P) provide additional insight into the transmissibility of the disease, epidemic trajectory, and the impact of NPIs. We assess how implementation of NPIs in early 2021 will shape the epidemic during the period of likely vaccine rollout. Results C19P burial data in Jakarta suggest a death toll approximately 3.3 times higher than reported. Transmission estimates using these data suggest earlier, larger, and more sustained impact of NPIs. Measures to reduce sub-national spread, particularly during Ramadan, substantially mitigated spread to more vulnerable rural areas. Given current trajectory, daily cases and deaths are likely to increase in most regions as the vaccine is rolled out. Transmission may peak in early 2021 in Jakarta if current levels of control are maintained. However, relaxation of control measures is likely to lead to a subsequent resurgence in the absence of an effective vaccination campaign. Conclusions Syndromic measures of mortality provide a more complete picture of COVID-19 severity upon which to base decision-making. The high potential impact of the vaccine in Java is attributable to reductions in transmission to date and dependent on these being maintained. Increases in control in the relatively short-term will likely yield large, synergistic increases in vaccine impact.

Insight into the impact of EGFR L792Y/F/H mutations on sensitivity to osimertinib: an in silico study

2021 ◽  
Vol 45 (10) ◽  
pp. 4756-4765
Author(s):  
Daoxing Chen ◽  
Liting Zhang ◽  
Yanan Liu ◽  
Jiali Song ◽  
Jingwen Guo ◽  
...  
Keyword(s):  
In Silico ◽  
In Silico Study ◽  
The Impact ◽  
Insight Into

EGFR L792Y/F/H mutation makes it difficult for Osimertinib to recognize ATP pockets.

The RUMA Alliance targets: an overview

Livestock ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 176-179
Author(s):  
Chris Lloyd
Keyword(s):  
Task Force ◽  
Animal Health ◽  
Antibiotic Use ◽  
Codes Of Practice ◽  
The Government ◽  
The Uk ◽  
Ongoing Support ◽  
The Impact ◽  
Insight Into ◽  
Roll Out

The Responsible Use of Medicines in Agriculture Alliance (RUMA) was established to promote the highest standards of food safety, animal health and animal welfare in the British livestock industry. It has a current focus to deliver on the Government objective of identifying sector-specific targets for the reduction, refinement or replacement of antibiotics in animal agriculture. The creation and roll out of sector specific targets in 2017 through the RUMA Targets Task Force, has helped focus activity across the UK livestock sectors to achieve a 50% reduction in antibiotic use since 2014. This has been realised principally through voluntary multi-sector collaboration, cross sector initiatives, codes of practice, industry body support and farm assurance schemes. This article provides an overview of RUMA's work to date providing insight into the methods used to create the targets, why they are so important, the impact they are having and how ongoing support and robust data are vital components in achieving the latest set of targets.

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