scholarly journals Atmospheric, Geomorphological, and Compositional Analysis of Martian Asimov and Hale Craters: Implications for Recurring Slope Lineae

2022 ◽  
Vol 8 ◽  
Author(s):  
Fares M. Howari ◽  
Manish Sharma ◽  
Cijo M. Xavier ◽  
Yousef Nazzal ◽  
Fatima Alaydaroos
Keyword(s):  
Compositional Analysis ◽  
Surface Characteristics ◽  
Open Science ◽  
Imaging Spectrometer ◽  
Atmosphere Interaction ◽  
Main Factors ◽  
Recurring Slope Lineae ◽  
Steep Slopes ◽  
Compositional Study ◽  
Observation Period

Recurring slope lineae (RSL) are small, dark, seasonal albedo features lengthening down “warm” Martian steep slopes. Their origin has been attributed to both liquid and dry processes, hence representing one of the major open science questions on present day Mars. In the present study, we report a catalog of previous literature and newly added RSL sites making a total of 940 sites globally on Mars along with the detailed geological and compositional investigation of the Hale and Asimov craters with their RSL features. We also estimate temperature and atmospheric water abundances in the study area, which are two of the main factors to explain the origin and formation of RSL. The study found that the Asimov crater’s local temperatures are high enough to allow either the melting of brines or deliquescence of calcium perchlorate and other salts during the HiRISE observation period and found the water vapor column to be nearly five times higher than those measured “before RSL appearance.” This supports the theory of deliquescence as one of the mechanisms for the regolith-atmosphere interaction and RSL formation in the studied crater, which suggests that minerals absorb moisture from the environment until the minerals dissolve in the absorbed water and yield a solution. We also used compact reconnaissance imaging spectrometer for Mars–derived browse products for a compositional study associated with RSL features hosting craters and surface characteristics of Mars.

scholarly journals Chronological Analysis and Remote Sensing of Craters on the Surface of Mars

2021 ◽  
Vol 9 ◽  
Author(s):  
Fares M. Howari ◽  
Manish Sharma ◽  
Cijo M. Xavier ◽  
Yousef Nazzal ◽  
Fatima AlAydaroos
Keyword(s):  
Compositional Analysis ◽  
Landing Site ◽  
Surface Characteristics ◽  
High Elevation ◽  
Imaging Spectrometer ◽  
Machine Learning Approach ◽  
Geological Formation ◽  
Southern Side ◽  
Geological Boundaries ◽  
Geological Units

In the present research, we carried out detailed chronological and compositional analyses along with detailed spectral analysis of three unnamed craters on the surface of Mars. Knowledge on chronology/age analysis and compositional analysis of Mars’ surface is essential for future manned and unmanned missions. The study area is near the landing site of previous landed missions, which could be used for future landing. The area is interesting to be studied because of its high elevation in the northeastern side and low elevation in the southern side, consisting of three major geological boundaries, i.e., Hesperian, Noachian, and Amazonian, which are further subdivided into fourteen units. Chronological investigations were carried out using the active machine learning approach and Craterstats 2.0 software, which revealed the age plot of 3.09 ± 0.04 Ga for Amazonian, 3.63 ± 0.0 Ga for Hesperian, and 3.73 ± 0.0 Ga for Noachian geological units, stating that N(1) craters’ density corresponds to the early Amazonian, early Hesperian, and late Noachian/early Hesperian periods according to the established crater density boundaries, respectively. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM)-derived browse products are used for the compositional study of the surface characteristics of Mars. A spectral investigation was performed on an unnamed crater belonging to the Amazonian period, which showed to be majorly composed of oxides as the primary mineral, indicating the spectra of hematite, boehmite, and akaganeite. A Hesperian unit-unnamed crater shows the signature of monohydrated sulfates, melilite, illite, and kaolinite minerals in the region. For the unnamed crater 3, which belongs to the Noachian period, it has diagnostic absorptions of clay minerals in their extracted spectra, indicating the sign of long-term water–rock interactions in the period. Derived chronology results and compositional studies of craters help in better understanding the geological formation units of Mars’ surface.

scholarly journals The Study of Personality Architecture and Dynamics (SPeADy): A Longitudinal and Extended Twin Family Study

2019 ◽  
Vol 22 (6) ◽  
pp. 548-553 ◽  
Author(s):  
Christian Kandler ◽  
Angelika Penner ◽  
Julia Richter ◽  
Alexandra Zapko-Willmes
Keyword(s):  
Data Collection ◽  
Family Study ◽  
Longitudinal Design ◽  
Personality Development ◽  
Surface Characteristics ◽  
Open Science ◽  
Moral Foundations ◽  
Major Life Events ◽  
Major Life ◽  
Children Of Twins

AbstractThe Study of Personality Architecture and Dynamics (SPeADy) is a German research project that aims to investigate the sources of interindividual differences in intraindividual personality development. The main focus lies in the dynamic interplay between more stable core characteristics and more environmentally malleable surface characteristics, as well as between personality and life experiences over time. SPeADy includes a twin family study encompassing data from 1962 individuals (age: 14–94) of 682 families, including 570 complete twin pairs (plus 1 triplet set), 327 parents, 236 spouses and 145 children of twins. Data collection started in 2016 and data from the first wave are currently obtainable as open source. Available data comprise a broad range of personality variables, such as personality trait constructs, motives, interests, values, moral foundations, religiosity and self-related concepts. For the currently ongoing second wave of data collection, we added retrospective reports on major life events. Special features of this genetically informative study are the extended twin family data and its longitudinal design. Three assessment waves in 2 years’ intervals are planned until 2022. In this article, we briefly describe the design and contents of the SPeADy twin family study as well as some recent findings, future plans and open science issues.

scholarly journals First-principles study of the structural, electronic, and elastic properties of Sc2SiX (X=C, N)

2021 ◽  
Vol 67 (3 May-Jun) ◽  
pp. 500
Author(s):  
M. Mebrek ◽  
M. Berber ◽  
B. Doumi ◽  
A. Mokaddem
Keyword(s):  
Electronic Properties ◽  
Elastic Constants ◽  
First Principles ◽  
Formation Energy ◽  
Elastic Anisotropy ◽  
Surface Characteristics ◽  
Hexagonal Structure ◽  
Main Factors ◽  
The Individual ◽  
First Time

Using ab-initio calculations, we studied the structural, elastic, and electronic properties of Sc2SiX compounds with, (X=C, N). The negative formation energy and the positive cohesive energy indicate that these compounds are energetically stable and can be synthesized in normal conditions. Sc2SiC and Sc2SiN compounds are mechanically stable, estimated by the individual elastic constants. Elastic constants and modulus increase when C is substituted by N. The elastic anisotropy in Sc2SiC is high compared to Sc2SiN. Both nanolaminates are fragile in nature. Sc2SiC is more conductive than Sc2SiN. The calculated electron band structures and the density of states imply that the chemical bond in two compounds is a combination of covalent, ionic, and metallic nature. The main factors governing the electronic properties are the hybrid states Sc- 3d, Si-3p, and C -2p and the bond (p-d) stabilizes the structure. Fermi's surface characteristics have been studied for the first time, which are changed when replacing N by C. Based on the estimate of the total energy, we conclude that the replacement of C by N will lead to a stabilization of the hexagonal structure and a decrease of the metallic support.

Early Roman copper-alloy brooch production: a compositional analysis of 400 brooches from Germania Inferior

2016 ◽  
Vol 29 ◽  
pp. 411-421 ◽  
Author(s):  
Marcus Roxburgh ◽  
Stijn Heeren ◽  
Hans Huisman ◽  
Bertil Van Os
Keyword(s):  
Iron Age ◽  
Copper Alloy ◽  
Compositional Analysis ◽  
Archaeological Sites ◽  
Liquid Form ◽  
Late Iron Age ◽  
Metal Artefacts ◽  
Large Numbers ◽  
Lead Zinc ◽  
Compositional Study

We present here a compositional study of a large number of copper-alloy brooches, undertaken in 2014 using Handheld X-ray Fluorescence Spectrometry (HHpXRF). The brooches, which come from the area of Nijmegen, date from the Late Iron Age until the 2nd c. A.D. Our aim is to explore the ways in which artefact production was organized both in the context of Roman centres and in the countryside. The link between alloys and workshop organization will be elucidated before the methodology and results are presented. The results will then be discussed, leading to the formation of several hypotheses regarding the organization of workshops that produced metal artefacts.Scientific interest in the composition of ancient artefacts has existed for well over two centuries. Roman brooches in particular have been in the forefront of this research both because of their ease of categorization and because they are found in large numbers on archaeological sites. Much work has been done on how they were made and on the technical choices available to the craftsmen. In particular, the choice of alloying agents (tin, lead, zinc) added to copper demonstrated a complex relationship between composition and typology, especially in the debate over Roman or local production. The technological restraints imposed on these artefacts by different alloy ratios have been studied in some detail, especially in terms of casting in liquid form, into a mould, or being wrought through beating with a hammer.

Formation of temperature regime of permafrost soils of the bases of buildings at the territory of multi-storey housing development of the city of Yakutsk

2019 ◽  
pp. 70-76
Keyword(s):  
Temperature Regime ◽  
Technical Regulation ◽  
Temperature Changes ◽  
Entire Observation Period ◽  
Permafrost Soils ◽  
Main Factors ◽  
Capital Construction ◽  
The City ◽  
Observation Period

The results of long-term observations of the temperature regime of soils in the territory of the Yakutsk, as the largest city, built under the conditions of permafrost soils are presented. The process of forming the temperature regime of permafrost soils of bases of buildings and structures is considered. The main factors and regularities of the process are analyzed. The dynamics of temperature changes in permafrost soils at a depth of 10 meters over the entire observation period is presented. The results are compared with the data of other researchers. Measures are proposed to improve the monitoring of thermal regime of the foundations of capital buildings under the conditions of preservation of permafrost soils. The tendencies and regularities of the formation of the temperature regime of the soils of the foundations of buildings and structures in the territory of capital construction under the conditions of the cryolithozone are revealed. Relationship with climatic and technogenic impacts, as well as with problems arising during the operation of buildings and structures, has been established. The research results can be taken into account when designing and constructing buildings and structures in other areas of permafrost with similar geocryological conditions. Recommendations on the technical regulation of temperature regime monitoring of permafrost soils of the cryolithozone have been developed.

3D multi-resolution mapping of Valles Marineris for better understanding of RSL formation

2020 ◽  
Author(s):  
Yu Tao ◽  
Jan-Peter Muller ◽  
Susan Conway
Keyword(s):  
High Resolution ◽  
Liquid Water ◽  
Imaging System ◽  
Laser Altimeter ◽  
Imaging Spectrometer ◽  
Valles Marineris ◽  
Digital Terrain ◽  
Imaging Science ◽  
Resolution Mapping ◽  
Recurring Slope Lineae

<p>Recurring Slope Lineae (RSLs) are metre- to decametre-wide dark streaks found on steep slopes, which lengthen downslope during the warmest times of the year, fading during the cooler periods and reappearing again in the next Martian year. This behaviour has been linked to the action of liquid water, but as liquid water is thermodynamically unstable under current martian conditions this interpretation is under vigorous debate. A better understanding of the formation process of RSLs is therefore fundamental to constraining Mars’ water budget and habitability. One of the key components for studying the RSL process is accurate knowledge of the slopes and aspects.</p><p> </p><p>The Valles Marineris (VM) area has the highest concentration of RSLs found on Mars as well as being a location where the triple point of water can be reached during the Martian summertime. This study focuses on multi-resolution 3D mapping of the whole VM area with all digital terrain models (DTMs) vertically referenced to the global standard Mars Orbiter Laser Altimeter (MOLA) surface. A multi-resolution DTM has been generated consisting of 82 Mars Express High Resolution Camera (HRSC) 50m DTMs and 1763 Mars Reconnaissance Orbiter (MRO) Context Camera (CTX) 18m DTMs which will be presented. For 3 selected study areas (Coprates Montes, Capri Mensa, Nectaris Montes), terrain corrected and co-registered MRO High Resolution Imaging Science Experiment (HiRISE; at 0.25m), Compact Reconnaissance Imaging Spectrometer for Mars (CRISM; at 20/50m) and ExoMars Trace Gas Orbiter (TGO) Colour and Stereo Surface Imaging System (CaSSIS; at 2.5m) colour images and associated DTMs will be discussed.</p><p> </p><p><strong>Acknowledgements</strong></p><p>The research leading to these results is receiving funding from the UKSA Aurora programme (2018-2021) under grant no. ST/S001891/1.</p>

Structural characterization of Zn–In–Se thin films

2017 ◽  
Vol 31 (05) ◽  
pp. 1750043 ◽  
Author(s):  
H. H. Güllü ◽  
M. Parlak
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Film Surface ◽  
Compositional Analysis ◽  
Surface Characteristics ◽  
Thermal Evaporation Method ◽  
Near Surface ◽  
X Ray ◽  
Force Microscopy ◽  
Thin Film Surface

In this study, structural properties of the Zn–In–Se (ZIS) thin films deposited by thermal evaporation method were investigated. The as-grown and annealed ZIS films were found in polycrystalline structure with the main orientation in (112) direction. The compositional analysis of the films showed that they were in Zn-rich behavior and there was a slight change in the elemental contribution to the structure with annealing process. Raman analysis was carried out to determine the crystalline structure and the different vibration modes of ZIS thin films. According to these measurements, the highest Raman intensity was in the LO mode which was directly proportional to the crystallinity of the samples. The atomic force microscopy (AFM) analyses were done in order to obtain detailed information about the morphology of the thin film surface. The surface of the films was observed as nearly-smooth and uniform in as-grown and annealed forms. X-ray photoelectron spectroscopy (XPS) measurements were analyzed to get detailed information about surface and near-surface characteristics of the films. The results from the surface and depth compositional analyses of the films showed quite good agreement with the energy dispersive X-ray spectroscopy (EDS) analysis.

Compositional Analysis of III-V Interface Lattice Images

1980 ◽  
Vol 38 ◽  
pp. 318-319
Author(s):  
A. Olsen ◽  
J.C.H. Spence ◽  
P. Petroff
Keyword(s):  
Crystal Structure ◽  
Image Matching ◽  
Compositional Analysis ◽  
Depth Of Field ◽  
Limit Set ◽  
High Contrast ◽  
Resolution Limit ◽  
Fourier Image ◽  
Lattice Images ◽  
True Structure

Since the point resolution of the JEOL 200CX electron microscope is up = 2.6Å it is not possible to obtain a true structure image of any of the III-V or elemental semiconductors with this machine. Since the information resolution limit set by electronic instability (1) u0 = (2/πλΔ)½ = 1.4Å for Δ = 50Å, it is however possible to obtain, by choice of focus and thickness, clear lattice images both resembling (see figure 2(b)), and not resembling, the true crystal structure (see (2) for an example of a Fourier image which is structurally incorrect). The crucial difficulty in using the information between Up and u0 is the fractional accuracy with which Af and Cs must be determined, and these accuracies Δff/4Δf = (2λu2Δf)-1 and ΔCS/CS = (λ3u4Cs)-1 (for a π/4 phase change, Δff the Fourier image period) are strongly dependent on spatial frequency u. Note that ΔCs(up)/Cs ≈ 10%, independent of CS and λ. Note also that the number n of identical high contrast spurious Fourier images within the depth of field Δz = (αu)-1 (α beam divergence) decreases with increasing high voltage, since n = 2Δz/Δff = θ/α = λu/α (θ the scattering angle). Thus image matching becomes easier in semiconductors at higher voltage because there are fewer high contrast identical images in any focal series.

High Spatial Resolution Compositional Analysis at Interfaces

1980 ◽  
Vol 38 ◽  
pp. 356-359
Author(s):  
John B. Vander Sande ◽  
Thomas F. Kelly ◽  
Douglas Imeson
Keyword(s):  
Electron Microscope ◽  
High Spatial Resolution ◽  
Compositional Analysis ◽  
Scanning Transmission Electron Microscope ◽  
Thin Specimen ◽  
X Ray ◽  
Volume Of Interest ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Energy Loss

In the scanning transmission electron microscope (STEM) a fine probe of electrons is scanned across the thin specimen, or the probe is stationarily placed on a volume of interest, and various products of the electron-specimen interaction are then collected and used for image formation or microanalysis. The microanalysis modes usually employed in STEM include, but are not restricted to, energy dispersive X-ray analysis, electron energy loss spectroscopy, and microdiffraction.

Sign in / Sign up

Export Citation Format

Share Document