The chemistry of carbon in the lunar regolith

1977 ◽  
Vol 285 (1327) ◽  
pp. 369-377 ◽  
Keyword(s):  
Solar Wind ◽  
Chemical Reactions ◽  
Metallic Iron ◽  
Lunar Regolith ◽  
Current Status ◽  
Reactive Carbon ◽  
Lunar Soils ◽  
The Matrix ◽  
Micrometeorite Impact

The current status of knowledge concerning the chemistry of carbon in the lunar regolith is discussed. The respective roles of the solar wind and micrometeorite impact in contributing carbon and providing energy to stimulate chemical reactions and mobilize carbon phases are examined. Most detailed information has been obtained by releasing trapped species and decomposing reactive carbon phases by dissolution of lunar soils in concentrated deuterium labelled acids. The method has substantiated that hydrocarbons deriving from solar wind implanted carbon and hydrogen are present in the silicate. In addition to trapped species, a number of carbon phases chemically bound to the matrix have been recognized. The most important of these are an acid hydrolysable species associated with metallic iron and what appears to be a discrete ionic carbide which liberates acetylene. Although the majority of the solar wind implanted carbon may be released and quantitated by pyrolysis there is little information to identify which elements were bonded to the carbon in the sample, if indeed any bonds were present at all.

Computational prediction of chemical reactions: current status and outlook

2018 ◽  
Vol 23 (6) ◽  
pp. 1203-1218 ◽  
Author(s):  
Ola Engkvist ◽  
Per-Ola Norrby ◽  
Nidhal Selmi ◽  
Yu-hong Lam ◽  
Zhengwei Peng ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Computational Prediction ◽  
Current Status

Implementing Electronic Portfolios at Bowling Green State University

2011 ◽  
pp. 388-397 ◽  
Author(s):  
Milton D. Hakel ◽  
Mark H. Gromko ◽  
Jessica L. Blackburn
Keyword(s):  
Electronic Portfolio ◽  
Electronic Portfolios ◽  
Current Status ◽  
State University ◽  
Green State ◽  
Bowling Green State University ◽  
The Matrix ◽  
Assessment Committee ◽  
Key Features ◽  
The University

This chapter outlines the implementation of electronic portfolio technology as part of a university initiative to improve learning. The implementation of electronic portfolios, via Epsilen Software, is discussed in terms of key features deemed necessary by Bowling Green State University’s assessment committee. One of the key features of the software is the matrix. This matrix is discussed in terms of its use for documenting student learning on the university’s learning outcomes. Reactions from current users are also provided. The chapter concludes by providing the current status of electronic portfolio usage at the university and a discussion of future plans for the software.

scholarly journals Untangling the formation and liberation of water in the lunar regolith

2019 ◽  
Vol 116 (23) ◽  
pp. 11165-11170 ◽  
Author(s):  
Cheng Zhu ◽  
Parker B. Crandall ◽  
Jeffrey J. Gillis-Davis ◽  
Hope A. Ishii ◽  
John P. Bradley ◽  
...  
Keyword(s):  
Solar Wind ◽  
Hydroxyl Radicals ◽  
Laboratory Experiments ◽  
Synergistic Effects ◽  
Lunar Regolith ◽  
Laboratory Simulation ◽  
The Moon ◽  
Imaging Studies ◽  
Simulation Experiments ◽  
Proton Implantation

The source of water (H2O) and hydroxyl radicals (OH), identified on the lunar surface, represents a fundamental, unsolved puzzle. The interaction of solar-wind protons with silicates and oxides has been proposed as a key mechanism, but laboratory experiments yield conflicting results that suggest that proton implantation alone is insufficient to generate and liberate water. Here, we demonstrate in laboratory simulation experiments combined with imaging studies that water can be efficiently generated and released through rapid energetic heating like micrometeorite impacts into anhydrous silicates implanted with solar-wind protons. These synergistic effects of solar-wind protons and micrometeorites liberate water at mineral temperatures from 10 to 300 K via vesicles, thus providing evidence of a key mechanism to synthesize water in silicates and advancing our understanding on the origin of water as detected on the Moon and other airless bodies in our solar system such as Mercury and asteroids.

Chemiluminescence measurement of gel times for amine-cured epoxy resins

1995 ◽  
Vol 7 (2) ◽  
pp. 219-236 ◽  
Author(s):  
K A Kozielski ◽  
N C Billingham ◽  
G A George ◽  
D C L Greenfield ◽  
J M Barton
Keyword(s):  
Chemical Reactions ◽  
Epoxy Resins ◽  
Physical State ◽  
Glycidyl Ether ◽  
Cross Linking ◽  
Gel Time ◽  
The Matrix ◽  
Effect Of Impurities ◽  
The Cross

The cross-linking reactions of 4,4'-diaminodiphenyl sulphone (DDS) with stoichiometric quantities of glycidyl ether- or tetraglycidyl amine-based epoxy resins were monitored using chemiluminescence (CL) and rheometry. It was found that, when a sample was cured isothermally in air, the CL profile increased to a maximum, then decreased again. The maximum was found to correspond well with the gel time (tgel), as measured by rheometry. This observation is discussed in relation to the chemical reactions occurring within the material and the physical state of the matrix. The effect of impurities in DDS on the gel time of these epoxy resins is reported.

scholarly journals Comprehensive Analysis on the Performance and Material of Automobile Brake Discs

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 377 ◽  
Author(s):  
Wanyang Li ◽  
Xuefeng Yang ◽  
Shouren Wang ◽  
Jupeng Xiao ◽  
Qimin Hou
Keyword(s):  
Current Status ◽  
Future Research ◽  
Brake Disc ◽  
Main Research ◽  
Brake Discs ◽  
The Matrix ◽  
Fiber Materials ◽  
Brake Noise ◽  
Composite Heat ◽  
Automotive Brake

This article reviews the current status of automotive brake disc research and the prospects for future research. At present, the research of brake disc performance mainly includes thermal conductivity, thermal fatigue resistance, wear resistance, and brake noise. It is found that a new alloy composite, heat treatment process, ceramic composite, new structure, and new materials are emerging. At the same time, it was found that ceramic and resin were used as the matrix, fiber materials were used as reinforcements to prepare brake discs, the addition of new fillers and the study of special reinforcement materials have become new hotspots in the study of brake discs. In the future development, carbon-fiber ceramic brake discs may become the main research focus of brake discs.

scholarly journals A REVIEW OF THE MAGNITUDES OF THE CKM MATRIX ELEMENTS

2008 ◽  
Vol 23 (31) ◽  
pp. 4945-4958 ◽  
Author(s):  
FRANCESCA DI LODOVICO
Keyword(s):  
Standard Model ◽  
Current Status ◽  
Matrix Elements ◽  
Ckm Matrix ◽  
The Standard Model ◽  
The Matrix ◽  
The Absolute ◽  
Ckm Matrix Elements

Flavour mixing is described within the Standard Model by the Cabibbo–Kobayashi–Maskawa (CKM) matrix elements. With the increasingly higher statistics collected by many experiments, the matrix elements are measured with improved precision, allowing for more stringent tests of the Standard Model. In this paper, a review of the current status of the absolute values of the CKM matrix elements is presented, with particular attention to the latest measurements.

Austenitic Oxide Dispersion Strengthened Steels : A Review

2016 ◽  
Vol 66 (4) ◽  
pp. 316 ◽  
Author(s):  
Lavanya Raman ◽  
Karthick Gothandapani ◽  
B.S. Murty
Keyword(s):  
Oxide Dispersion Strengthened ◽  
Current Status ◽  
Oxide Dispersion ◽  
Hard Particles ◽  
Void Swelling ◽  
The Matrix ◽  
Swelling Characteristics ◽  
Ods Steels ◽  
Breeder Reactors ◽  
Materials Used

Materials play an important role in the fast breeder reactors.  Materials used in cladding tube and fuel pins should have better creep and void swelling resistance. To overcome these difficulties, a new class of material known as oxide dispersion strengthened (ODS) steels are used. There are two groups of ODS steels, the ferritic and the austenitic ODS steels based on the matrix. The present paper reviews the current status of research in austenitic ODS steels. The interaction of dislocations with finely dispersed incoherent, hard particles that governs the strength and high temperature properties of ODS materials is briefly reviewed. The synthesis route adopted for these ODS steels, which is mostly through powder metallurgy route is also discussed. The role of various oxides such as Y2O3, ZrO2and TiO2and the clusters formed in these ODS steels on the mechanical properties and void swelling characteristics is also discussed.

scholarly journals Reaction–diffusion basis of retroviral infectivity

2016 ◽  
Vol 374 (2080) ◽  
pp. 20160148 ◽  
Author(s):  
S. Kashif Sadiq
Keyword(s):  
Chemical Reactions ◽  
Membrane Surface ◽  
Reaction Diffusion ◽  
Coarse Graining ◽  
Coarse Grained ◽  
Multiscale Approach ◽  
The Matrix ◽  
Membrane Bound ◽  
Spatio Temporal ◽  
Dynamics Simulations

Retrovirus particle (virion) infectivity requires diffusion and clustering of multiple transmembrane envelope proteins (Env 3 ) on the virion exterior, yet is triggered by protease-dependent degradation of a partially occluding, membrane-bound Gag polyprotein lattice on the virion interior. The physical mechanism underlying such coupling is unclear and only indirectly accessible via experiment. Modelling stands to provide insight but the required spatio-temporal range far exceeds current accessibility by all-atom or even coarse-grained molecular dynamics simulations. Nor do such approaches account for chemical reactions, while conversely, reaction kinetics approaches handle neither diffusion nor clustering. Here, a recently developed multiscale approach is considered that applies an ultra-coarse-graining scheme to treat entire proteins at near-single particle resolution, but which also couples chemical reactions with diffusion and interactions. A model is developed of Env 3 molecules embedded in a truncated Gag lattice composed of membrane-bound matrix proteins linked to capsid subunits, with freely diffusing protease molecules. Simulations suggest that in the presence of Gag but in the absence of lateral lattice-forming interactions, Env 3 diffuses comparably to Gag-absent Env 3 . Initial immobility of Env 3 is conferred through lateral caging by matrix trimers vertically coupled to the underlying hexameric capsid layer. Gag cleavage by protease vertically decouples the matrix and capsid layers, induces both matrix and Env 3 diffusion, and permits Env 3 clustering. Spreading across the entire membrane surface reduces crowding, in turn, enhancing the effect and promoting infectivity. This article is part of the themed issue ‘Multiscale modelling at the physics–chemistry–biology interface’.

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