scholarly journals Elemental abundance distributions in suboceanic basalt glass: Evidence of biogenic alteration

2004 ◽  
Vol 5 (10) ◽  
pp. n/a-n/a ◽  
Author(s):  
M. C. Storrie-Lombardi ◽  
M. R. Fisk
Keyword(s):  
Elemental Abundance ◽  
Basalt Glass

scholarly journals Core Collapse Supernova Models and Nucleosynthesis

2013 ◽  
Vol 9 (S296) ◽  
pp. 27-36
Author(s):  
Ken'ichi Nomoto
Keyword(s):  
Big Bang ◽  
Elemental Abundance ◽  
Core Collapse ◽  
Solar Abundance ◽  
First Stars ◽  
Abundance Pattern ◽  
Core Collapse Supernova ◽  
Abundance Patterns ◽  
Supernova Explosions ◽  
The Big Bang

AbstractAfter the Big Bang, production of heavy elements in the early Universe takes place in the first stars and their supernova explosions. The nature of the first supernovae, however, has not been well understood. The signature of nucleosynthesis yields of the first supernovae can be seen in the elemental abundance patterns observed in extremely metal-poor stars. Interestingly, those abundance patterns show some peculiarities relative to the solar abundance pattern, which should provide important clues to understanding the nature of early generations of supernovae. We review the recent results of the nucleosynthesis yields of massive stars. We examine how those yields are affected by some hydrodynamical effects during the supernova explosions, namely, explosion energies from those of hypernovae to faint supernovae, mixing and fallback of processed materials, asphericity, etc. Those parameters in the supernova nucleosynthesis models are constrained from observational data of supernovae and metal-poor stars.

scholarly journals Low-latitude climate variability in the Heinrich frequency band of the Late Cretaceous greenhouse world

2014 ◽  
Vol 10 (3) ◽  
pp. 1001-1015 ◽  
Author(s):  
N. J. de Winter ◽  
C. Zeeden ◽  
F. J. Hilgen
Keyword(s):  
Deep Sea ◽  
Linear Response ◽  
Elemental Abundance ◽  
Milankovitch Cycles ◽  
Glacial Cycle ◽  
Low Latitude ◽  
Project Site ◽  
The Tropics ◽  
The Last Glacial ◽  
Drilling Project

Abstract. Deep marine successions of early Campanian age from DSDP (Deep Sea Drilling Project) site 516F drilled at low paleolatitudes in the South Atlantic reveal distinct sub-Milankovitch variability in addition to precession, obliquity and eccentricity-related variations. Elemental abundance ratios point to a similar climatic origin for these variations and exclude a quadripartite structure as an explanation for the inferred semi-precession cyclicity in the magnetic susceptibility (MS) signal as observed in the Mediterranean Neogene for precession-related cycles. However, semi-precession cycles as suggested by previous work are likely an artifact reflecting the first harmonic of the precession signal. The sub-Milankovitch variability, especially in MS, is best approximated by a ~7 kyr cycle as shown by spectral analysis and bandpass filtering. The presence of sub-Milankovitch cycles with a period similar to that of Heinrich events of the last glacial cycle is consistent with linking the latter to low-latitude climate change caused by a non-linear response to precession-induced variations in insolation between the tropics.

Gamma-Ray Spectrum Analysis of Chang’E-1 for Lunar Detection

2010 ◽  
Vol 133 (5) ◽  
Author(s):  
Xu HongKun ◽  
Fang Fang ◽  
Ni Shijun ◽  
He Jianfeng ◽  
You Lei
Keyword(s):  
Spectral Characteristic ◽  
Spectrum Analysis ◽  
Gamma Ray ◽  
Low Energy ◽  
Elemental Abundance ◽  
Nuclear Engineering ◽  
Gamma Ray Spectrometer ◽  
Lunar Prospector ◽  
Spectrometer Data ◽  
Wavelet Methods

Gamma-ray spectrum analysis was essential for radioactive environmental monitoring, and it had been widely used in many areas of nuclear engineering. However, for the low-energy region of gamma-ray spectrum, weak peaks were contained in the fast-decreasing background, so it was difficult to extract characteristic information from original spectra. In order to get a better analytic result based on wavelet methods in frequency domain, we had processed the gamma-ray spectrometer data of Chang’E-1 and well extracted some useful information of spectral characteristic peaks. Then, we preliminarily mapped the distribution of net peak counts for potassium on lunar surface, which indirectly reflected the distribution of elemental abundance. At last, we compared our analytic result with that of Apollo and Lunar Prospector and found some consistencies and differences.

scholarly journals Determination of Scandium in mafic and ultramafic rocks of ophiolites from Luk Ulo Complex, Karangsambung, Central Java, Indonesia

2020 ◽  
Vol 200 ◽  
pp. 06003
Author(s):  
Nugroho Imam Setiawan ◽  
Kardo Polarman Rajoki Silitonga ◽  
Fahmi Adiyatma Makkaratte ◽  
Chusni Ansori
Keyword(s):  
Mineral Composition ◽  
General Trend ◽  
Elemental Abundance ◽  
Ultramafic Rocks ◽  
Mining Activities ◽  
Central Java ◽  
Parent Rocks ◽  
Modern Industry

Scandium (Sc) is important element for its utilization in modern industry. Initial Sc content in the parent rocks primary importance controlling the Sc concentrations in its weathered derivatives. This contribution examines the Sc concentrations in parent rocks of mafic and ultramafic rocks related to the ophiolite series in Luk Ulo Complex, Karangsambung, Central Java, Indonesia. The ophiolite series in this area are basalt, microgabbronorite, gabbronorite, websterite, and serpentinite from 5 locations of Medana, Lokidang, Parakansubah, Selogiri, and Pucangan areas. The general trend from the distribution of Sc in the ophiolite sequence of Medana and Parakansubah-Lokidang Rivers suggests the Sc contents increase from shallow to deeper levels of the sequence. The lowest concentrations of Sc in the ophiolite sequence of Medana and Parakansubah-Lokidang Rivers are in basalt, which are 24–29 ppm. In the middle sequence, the Sc concentrations are 27–34 ppm and 24–43 ppm, respectively in microgabbronorite and gabbronorite. The highest Sc concentrations are in websterite, which are 51–54 ppm, as the deepest sequence of the ophiolite in this area. Meanwhile, Sc contents in serpentinite from Selogiri and Pucangan areas are 5–11 ppm, which are considered the lowest Sc contents. It suggests that the pre-serpentinization mineral composition rather than the process of serpentinization determine the elemental abundance of Sc in serpentinite. The results are used to be an analog for Sc identification in the ophiolite belts in central Indonesia. This also considering that Luk Ulo Complex been established as National Geopark of Karangsambung-Karangbolong, so that mining activities are prohibited in this area.

scholarly journals CRYSTAL STRUCTURE OF THE QUATERNARY SEMICONDUCTOR COMPOUND CuFeCrSe3

2019 ◽  
Vol 16 (32) ◽  
pp. 848-853
Author(s):  
Gerzon E. DELGADO ◽  
P. DELGADO-NIÑO ◽  
P. GRIMA-GALLARDO
Keyword(s):  
High Efficiency ◽  
Rietveld Method ◽  
Structural Parameters ◽  
Secondary Phase ◽  
Elemental Abundance ◽  
Tetragonal Symmetry ◽  
Potential Candidate ◽  
Quaternary Compound ◽  
Semiconductor Compound ◽  
Semiconductor System

The compounds with ternary structures of the chalcopyrite family Cu-III-Se2 (III = Al, Ga, In, Cr) form a wide group of semiconductor materials with diverse optical and electrical properties, and the addition of FeSe binary compound produces alloys of the type (Cu-III-Se2)1-x(Fe-Se)x. These types of materials have received increasing attention as promising thermoelectric materials due to their high efficiency, tunable transport properties, high elemental abundance and low toxicity. This work aims to synthesize and characterize structurally a new material belonging to this semiconductor system with x = ½, the quaternary compound CuFeCrSe3. This material was prepared by the melt and anneal technique and its structure was refined from Xray powder diffraction pattern using the Rietveld method. The X-ray powder pattern was mainly composed of CuFeCrSe3 (79.1%) with CuCr2Se4 (20.9%) appearing as secondary phase. The principal phase crystallizes with tetragonal symmetry in the space group P 4 2c (Nº 112), Z = 1, with a = 5.5082(2) Å, c = 10.943(1) Å, V = 332.01(1) Å3. The refinement of 18 instrumental and structural parameters led to Rp = 8.8 %, Rwp = 9.1 %, Rexp = 7.8 % and S = 1.2. This material, belonging to the semiconductor system I-II-III-VI3, crystallizes with a CuFeInSe3-type structure in a normal adamantane-structure. CuFeCrSe3 is a new semiconductor compound, related to the superionic phase CuCrSe2, and can be considered as a potential candidate for mediumtemperature thermoelectric applications.

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