Characterization of Mixture Formation Processes in D.I. Gasoline Sprays by the Laser Absorption Scattering (LAS) Technique - Effect of Injection Conditions

2003 ◽  
Author(s):  
Tie Li ◽  
Masahisa Yamakawa ◽  
Daisuke Takaki ◽  
Keiya Nishida ◽  
Yuyin Zhang ◽  
...  
Keyword(s):  
Formation Processes ◽  
Mixture Formation ◽  
Laser Absorption ◽  
Technique Effect

Aerothermodynamic Characterization of an Inductively Generated CO2Plasma by Laser Absorption Spectroscopy

2022 ◽  
Author(s):  
Hendrik Burghaus ◽  
Clemens F. Kaiser ◽  
Adam S. Pagan ◽  
Stefanos Fasoulas ◽  
Georg Herdrich
Keyword(s):  
Absorption Spectroscopy ◽  
Laser Absorption Spectroscopy ◽  
Laser Absorption

Current Questions and New Directions in Archaeological Obsidian Studies

2016 ◽  
Author(s):  
Carolyn Dillian
Keyword(s):  
Chemical Characterization ◽  
Current Status ◽  
Formation Processes ◽  
X Ray ◽  
Dating Methods ◽  
New Directions ◽  
Trade And Exchange

This article discusses the current status of archaeological obsidian studies, including techniques used in characterization and sourcing studies, obsidian hydration, and regional syntheses. It begins with an overview of obsidian and the unique formation processes that create it before turning to a discussion of the significance of characterization and sourcing techniques for understanding prehistoric obsidian trade and exchange. It then considers the problematic aspects of the term “sourcing,” despite its ubiquitous use in archaeology and archaeometry, along with the use of X-ray fluorescence in the chemical characterization of obsidian. It also explores obsidian hydration dating methods and equations, factors that can affect the date assignments for hydration specimens, and the various uses of obsidian in prehistoric times. Finally, it addresses some important questions relating to obsidian research and suggests new directions in the field.

scholarly journals Luminescence reveals variations in local structural order of calcium carbonate polymorphs formed by different mechanisms

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Michael B. Toffolo ◽  
Giulia Ricci ◽  
Luisa Caneve ◽  
Ifat Kaplan-Ashiri
Keyword(s):  
Infrared Spectroscopy ◽  
Calcium Carbonate ◽  
Construction Materials ◽  
Reference Database ◽  
Formation Processes ◽  
X Ray Diffraction ◽  
Structural Order ◽  
Lime Plaster ◽  
Calcium Carbonate Polymorphs

Abstract In nature, calcium carbonate (CaCO3) in the form of calcite and aragonite nucleates through different pathways including geogenic and biogenic processes. It may also occur as pyrogenic lime plaster and laboratory-precipitated crystals. All of these formation processes are conducive to different degrees of local structural order in CaCO3 crystals, with the pyrogenic and precipitated forms being the least ordered. These variations affect the manner in which crystals interact with electromagnetic radiation, and thus formation processes may be tracked using methods such as X-ray diffraction and infrared spectroscopy. Here we show that defects in the crystal structure of CaCO3 may be detected by looking at the luminescence of crystals. Using cathodoluminescence by scanning electron microscopy (SEM-CL) and laser-induced fluorescence (LIF), it is possible to discern different polymorphs and their mechanism of formation. We were thus able to determine that pyrogenic calcite and aragonite exhibit blue luminescence due to the incorporation of distortions in the crystal lattice caused by heat and rapid precipitation, in agreement with infrared spectroscopy assessments of local structural order. These results provide the first detailed reference database of SEM-CL and LIF spectra of CaCO3 standards, and find application in the characterization of optical, archaeological and construction materials.

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