scholarly journals The Interstellar Medium of Dwarf Galaxies

Galaxies ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 11
Author(s):  
Christian Henkel ◽  
Leslie K. Hunt ◽  
Yuri I. Izotov
Keyword(s):  
Interstellar Medium ◽  
Dwarf Galaxies ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Ionized Gas ◽  
Green Pea ◽  
Physical And Chemical ◽  
The Impact ◽  
The Universe ◽  
And Chemical Properties

Dwarf galaxies are by far the most numerous galaxies in the Universe, showing properties that are quite different from those of their larger and more luminous cousins. This review focuses on the physical and chemical properties of the interstellar medium of those dwarfs that are known to host significant amounts of gas and dust. The neutral and ionized gas components and the impact of the dust will be discussed, as well as first indications for the existence of active nuclei in these sources. Cosmological implications are also addressed, considering the primordial helium abundance and the similarity of local Green Pea galaxies with young, sometimes protogalactic sources in the early Universe.

scholarly journals An Overview of Dynamic Heterogeneous Oxidations in the Troposphere

Environments ◽  
2018 ◽  
Vol 5 (9) ◽  
pp. 104 ◽  
Author(s):  
Elizabeth Pillar-Little ◽  
Marcelo Guzman
Keyword(s):  
Atmospheric Aerosols ◽  
Atmospheric Transport ◽  
Cloud Condensation Nuclei ◽  
Complex Mixture ◽  
Organic Aerosols ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
The Impact ◽  
And Chemical Properties

Due to the adverse effect of atmospheric aerosols on public health and their ability to affect climate, extensive research has been undertaken in recent decades to understand their sources and sinks, as well as to study their physical and chemical properties. Atmospheric aerosols are important players in the Earth’s radiative budget, affecting incoming and outgoing solar radiation through absorption and scattering by direct and indirect means. While the cooling properties of pure inorganic aerosols are relatively well understood, the impact of organic aerosols on the radiative budget is unclear. Additionally, organic aerosols are transformed through chemical reactions during atmospheric transport. The resulting complex mixture of organic aerosol has variable physical and chemical properties that contribute further to the uncertainty of these species modifying the radiative budget. Correlations between oxidative processing and increased absorptivity, hygroscopicity, and cloud condensation nuclei activity have been observed, but the mechanisms behind these phenomena have remained unexplored. Herein, we review environmentally relevant heterogeneous mechanisms occurring on interfaces that contribute to the processing of aerosols. Recent laboratory studies exploring processes at the aerosol–air interface are highlighted as capable of generating the complexity observed in the environment. Furthermore, a variety of laboratory methods developed specifically to study these processes under environmentally relevant conditions are introduced. Remarkably, the heterogeneous mechanisms presented might neither be feasible in the gas phase nor in the bulk particle phase of aerosols at the fast rates enabled on interfaces. In conclusion, these surface mechanisms are important to better understand how organic aerosols are transformed in the atmosphere affecting the environment.

scholarly journals MgO Refractory Doped with ZrO2 Nanoparticles: Influence of Cold Isostatic and Uniaxial Pressing and Sintering Temperature in the Physical and Chemical Properties

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1297 ◽  
Author(s):  
Cristian Gómez-Rodríguez ◽  
Daniel Fernández-González ◽  
Linda Viviana García-Quiñonez ◽  
Guadalupe Alan Castillo-Rodríguez ◽  
Josué Amilcar Aguilar-Martínez ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Cold Isostatic Pressing ◽  
Zro2 Nanoparticles ◽  
Furnace Lining ◽  
Physical And Chemical Properties ◽  
X Ray ◽  
Isostatic Pressing ◽  
Physical And Chemical ◽  
The Impact ◽  
And Chemical Properties

The chemical environment and the internal conditions of the furnaces and ladles are extremely aggressive for the refractories, so metallurgical industries demand refractory linings with greater durability and resistance to avoid unforeseen stoppages and to reduce the changes of the furnace lining. Therefore, the current work aims to evaluate the impact of the additions of ZrO2-nanoparticles (1, 3, and 5 wt. %) in magnesia-based bricks. A comparative study of the physical and chemical properties in bricks obtained using two cold pressing techniques (uniaxial and isostatic pressing) and two sintering temperatures (1550 and 1650 °C) was carried out. The microstructure and crystalline phase characteristics obtained after the heat treatments and the slag corrosion test was studied using scanning electron microscopy/electron dispersive X-ray spectroscopy (SEM/EDX) and X-ray diffraction (XRD). The results reveal that the sample with 5 wt. % of ZrO2 nanoparticles (obtained by cold isostatic pressing and sintering at 1650 °C) has the lowest porosity and greatest resistance to penetration of blast furnace slag.

scholarly journals The kinetic parameters of aerosols formed during combustion of modified wood

2018 ◽  
Vol 251 ◽  
pp. 02023
Author(s):  
Feodor Portnov
Keyword(s):  
Grain Size ◽  
Surface Layer ◽  
Chemical Properties ◽  
Quantitative Composition ◽  
Kinetic Properties ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
The Impact ◽  
And Chemical Properties ◽  
Modified Wood

The paper studies kinetic properties of aerosols formed in thermal degradation of wood. The impact of modifying agents in wood surface layer on the quantitative composition of smoke aerosol solids was analyzed. For this purpose, grain-size of aerosol solids was analyzed, and the physical and chemical properties of source and modified wood were assessed.

Molecular Line Observations in the Magellanic Clouds

2005 ◽  
Vol 13 ◽  
pp. 854-859
Author(s):  
Mónica Rubio
Keyword(s):  
Interstellar Medium ◽  
Molecular Species ◽  
Chemical Properties ◽  
Present Knowledge ◽  
Magellanic Clouds ◽  
Molecular Gas ◽  
Physical And Chemical Properties ◽  
Molecular Line ◽  
Physical And Chemical ◽  
And Chemical Properties

AbstractWe review the present knowledge of molecular line studies and its relation to interstellar medium properties in the Large and Small Magellanic Clouds. The physical and chemical properties of the molecular gas together with the abundance of different molecular species will be discussed.

Non-symmetric pincer ligands: complexes and applications in catalysis

2015 ◽  
Vol 44 (40) ◽  
pp. 17432-17447 ◽  
Author(s):  
Matthew Asay ◽  
David Morales-Morales
Keyword(s):  
Organometallic Chemistry ◽  
Chemical Properties ◽  
Pincer Ligands ◽  
Physical And Chemical Properties ◽  
Structural Motifs ◽  
Physical And Chemical ◽  
The Impact ◽  
And Chemical Properties

Non-symmetric pincer ligands and their complexes have become relevant in different areas of chemistry greatly increasing the pincer structural motifs known and hence their physical and chemical properties. The impact of these species in organometallic chemistry and catalysis is discussed in this perspective.

Impact of Insufficient Cleaning on the Quality of Molybdenum Layer Applied by Thermal Spraying

2013 ◽  
Vol 801 ◽  
pp. 35-40
Author(s):  
Marián Bujna ◽  
Miroslav Prístavka ◽  
Pavol Kaplík
Keyword(s):  
Erosion Resistance ◽  
Thermal Spraying ◽  
Chemical Properties ◽  
Poor Quality ◽  
Physical And Chemical Properties ◽  
High Degree ◽  
Physical And Chemical ◽  
The Impact ◽  
And Chemical Properties

Thermal spraying influences several physical and chemical properties of the coating surface. The most important of them are hardness, density, porosity, corrosion resistance and adhesion. This technology of surface treatment of material is often used for its high degree of hardness. Hardness and erosion resistance are the parameters that need to be achieved particularly in working conditions where there is excessive component wear. In this paper, we deal with the impact of purifying on the quality of molybdenum layer. Insufficient cleaning may result in a poor quality of the sprayed layer. Our aim is to measure and analyse the quality of molybdenum layer thickness applied by thermal spraying after insufficient cleaning.

scholarly journals Influence of the Addition of Calcium Hydroxide Powder on Some Physical and Chemical Properties of the Sealer MTA Fillapex

2012 ◽  
Vol 3 (2) ◽  
pp. 180-183
Author(s):  
Marcelo Ferrarezi de Andrade ◽  
Renato de Toledo Leonardo ◽  
Edson Alves de Campos ◽  
Milton Carlos Kuga ◽  
Marco Antonio Hungaro Duarte ◽  
...  
Keyword(s):  
Calcium Hydroxide ◽  
Calcium Release ◽  
Ph Value ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Ph Values ◽  
The One ◽  
Physical And Chemical ◽  
The Impact ◽  
And Chemical Properties

ABSTRACT Objective This study evaluated the flow, pH and calcium release of MTA Fillapex (G1) or Fillapex plus 10% in weight of calcium hydroxide powder (G2), compared to AH Plus (G3) and Sealapex (G4). Materials and methods The flow test was performed according to ISO 6876:2001 requirements. The sealers were placed into plastic tubes and immersed in deionized water. After 24 hours, 7, 14 and 28 days, the water of each tube was removed and tested to evaluate the pH values and the level of released calcium. Calcium release values were analyzed statistically by Kruskal Wallis and Dunn tests and pH values analyzed by ANOVA and Tukey tests (α = 5%). Results G1 presented higher flow among all sealers. The addition of 10% calcium hydroxide into MTA Fillapex reduced the flow (p < 0.05) but, in a level, that is lower than the one recommended for ISO norms. G2 and G4 presented pH values and calcium release higher than G3 (p < 0.05) in all periods. G1 presented pH value higher than G3 (p < 0.05), except in 7 days period (p > 0.05). G4 presented higher pH values than G1 and G2, but the calcium release was similar for all periods (p > 0.05). G3 presented lower calcium release among all groups (p < 0.05). Conclusion The addition of 10% calcium hydroxide in MTA Fillapex caused reduction in flow and no negative interference in pH and/or calcium release. However, the obtained flow is different from ISO requirements. Clinical relevance MTA Fillapex presents levels of flow above the ISO norms. The addition of calcium hydroxide is a suggestion for solving this problem, but the impact of these procedures should be carefully evaluated. How to cite this article Keine KC, Guiotti FA, Leonardo RT, Kuga MC, Duarte MAH, de Campos EA, de Andrade MF. Influence of the Addition of Calcium Hydroxide Powder on Some Physical and Chemical Properties of the Sealer MTA Fillapex. World J Dent 2012;3(2):180-183.

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