scholarly journals Removal of Hydrogen Poisoning by Electrostatically Polar MgO Support for Low-Pressure NH3 Synthesis at a High Rate over the Ru Catalyst

ACS Catalysis ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 5614-5622 ◽  
Author(s):  
Simson Wu ◽  
Yung-Kang Peng ◽  
Tian-Yi Chen ◽  
Jiaying Mo ◽  
Alex Large ◽  
...  
Keyword(s):  
Low Pressure ◽  
High Rate ◽  
Ru Catalyst ◽  
Mgo Support

High rate low pressure plasma-enhanced chemical vapor deposition for barrier and optical coatings

2013 ◽  
Vol 532 ◽  
pp. 44-49 ◽  
Author(s):  
Steffen Günther ◽  
Matthias Fahland ◽  
John Fahlteich ◽  
Björn Meyer ◽  
Steffen Straach ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Low Pressure ◽  
High Rate ◽  
Optical Coatings ◽  
Pressure Plasma ◽  
Low Pressure Plasma

High Rate, High Quality, Diamond Synthesis by the Combustion Flame Process

1994 ◽  
Vol 349 ◽  
Author(s):  
K.V. Ravi ◽  
D.S. Olson ◽  
C.A. Koch
Keyword(s):  
Diamond Films ◽  
Chemical Vapor ◽  
Low Pressure ◽  
High Rate ◽  
Synthesis Process ◽  
Oh Radicals ◽  
Diamond Synthesis ◽  
Large Area ◽  
Combustion Flame ◽  
Bulk Diamond

ABSTRACTAmong the various low pressure techniques being developed for the synthesis of diamond films and bulk diamond slabs the combustion flame synthesis process has some distinct advantages. In this approach the combustion reaction between acetylene and oxygen is utilized to generate the requisite energy to activate excess acetylene in the gas mix leading to the deposition of diamond films on a temperature controlled substrate brought into contact with the flame. Other diamond synthesis approaches, such as microwave enhanced and the filament assisted chemical vapor deposition processes, and the various arc jet techniques utilize mixtures of hydrogen and methane as the process gases. Oxygen and oxidizing specie ( such as OH radicals) in the flame ambient may be much more effective than atomic hydrogen in promoting the growth of diamond over the growth of graphite and other non- diamond forms of carbon. In addition this technique enables the growth of diamond at high rates and is relatively easily scaled for large area synthesis. In this paper a discussion of this technique is presented drawing upon recent research by the authors as well as published work to present a general discussion of the issues involved in the development of this technique of low pressure diamond synthesis.

Geology, geochronology and chemical evolution of the island of Pantelleria

1984 ◽  
Vol 121 (6) ◽  
pp. 541-562 ◽  
Author(s):  
L. Civetta ◽  
Y. Cornette ◽  
G. Crisci ◽  
P. Y. Gillot ◽  
G. Orsi ◽  
...  
Keyword(s):  
Magma Chamber ◽  
Low Pressure ◽  
High Rate ◽  
Crustal Material ◽  
Volcanic System ◽  
Strait Of Sicily ◽  
Argon Dating ◽  
Liquid Fractionation ◽  
Different Levels ◽  
Eruptive Cycles

AbstractPotassium–argon dating, field relations, geochemical and strontium-isotope compositions are reported for the island of Pantelleria (Strait of Sicily, Italy). These data support the following model for the genesis and evolution through time of the volcanic system: the peralkaline rocks originated from mantle-derived parental magmas; the trachytic magma differentiated in a low pressure magma chamber by crystal–liquid fractionation. This process led to a chemically zoned magma chamber tapped at different levels by successive eruptions. During low-pressure differentiation the 87Sr/86Sr ratios of some of the most evolved Sr-poor rhyolitic magmas increased from 0.703 up to 0.708 by contamination with crustal material.The chemical variation displayed by the products of each of the defined eruptive cycles in the last 50000 years suggests an open system behaviour of the magma chamber which is episodically refilled by more mafic parent magma, differentiated at high rate and episodically erupted.

Scalable high-rate production of non-agglomerated nanopowders in low pressure flames

1998 ◽  
Vol 34 (3-6) ◽  
pp. 148-153 ◽  
Author(s):  
N.G. Glumac ◽  
Y.-J. Chen ◽  
G. Skandan ◽  
B. Kear
Keyword(s):  
Low Pressure ◽  
High Rate

scholarly journals CAVITATION-EROSION STUDY IN ELBOW TUBES OF A LOW-PRESSURE EVAPORATOR OUTLET HEADER

Metalurgi ◽  
2020 ◽  
Vol 35 (1) ◽  
pp. 33
Author(s):  
Dewa Nyoman Adnyana
Keyword(s):  
Cavitation Erosion ◽  
Low Pressure ◽  
Hot Water ◽  
High Rate ◽  
Working Fluid ◽  
Outer Diameter ◽  
Low Carbon ◽  
Two Phase ◽  
Surface Appearance ◽  
Study Results

This paper presents the results of the cavitation-erosion study that occurred on elbow tubes that connected to the low-pressure (LP) Evaporator outlet header on a heat-recovery steam generator (HRSG) unit. Inside the elbow tubes flow the working fluid in the form of hot water with a pressure of 10 bar and a temperature of 160° C. Elbow tubes are made of low carbon steel, have an outer diameter of 31.8 mm and a wall thickness of 2.6 mm. Before entering into the elbow tubes, the working fluid warms up inside the evaporator tubes panel using hot flue gases coming from a gas turbine power plant unit. In this study there were 4 (four) pieces of post-service elbow tubes used, namely elbow tube with the connecting angle of 90°, 75°, 60° and 45°. The types of tests carried out included macroscopic tests, chemical analysis, metallographic examinations, hardness tests and EDS (energy dispersive spectroscopy) analysis. The study results obtained show that the elbow tubes undergo a process of thinning on the inner wall of the outer curvature with a rough and jagged surface appearance. This type of failure is known cavitation- erosion. The level of cavitation-erosion that occurs is very much influenced by the elbow’s connecting angle with the LP Evaporator header outlet. The greater the connecting angle or the smaller the radius of the elbow tube, the higher the level of cavitation-erosion that occurs. The high rate of cavitation-erosion experienced by the four elbow tubes is also related to the level of turbulence of the working fluid flow that occurs in the elbow tube. The increase in turbulence that occurs is caused by a decrease in the pressure of the working fluid in the evaporator panel so that some part of the working fluid turns into steam and produces a two-phase flow consisting of a mixture of water and steam

Synthesis of Nanocomposites by Ballistic Impaction of Nanoparticles

2005 ◽  
Author(s):  
R. Mukherjee ◽  
W. M. Mook ◽  
J. Hafiz ◽  
X. Wang ◽  
W. W. Gerberich ◽  
...  
Keyword(s):  
Beam Width ◽  
Low Pressure ◽  
Pressure Chamber ◽  
High Rate ◽  
New Class ◽  
Reaction Region ◽  
Flow Through ◽  
C And N ◽  
20 Nm ◽  
Beam Deposition

We are investigating ballistic impact assembly of nanoparticles to form a new class of materials for superhard coatings and micromolded MEMS parts. Nanoparticles are generated by dissociating vapor-phase reactants injected downstream of a thermal plasma and expanding the resultant flow through a converging nozzle into a low-pressure chamber. The nanoparticle-laden gases achieve hypersonic velocities due to the pressure difference between the reaction region (450 torr) and the low-pressure chamber (∼2 torr). Particles are deposited by one of two processes: (a) by placing a substrate 20mm downstream of the flow, which results in a bow shock at the substrate and high impact velocities (calculated to be over 2000 m/s for a 20 nm SiC particle): termed as high-rate deposition, (b) by focusing the particles into a tight beam (width of ∼35 (μm) using aerodynamic lenses, and subsequent impaction on a translating substrate: termed as focused beam deposition. Thus far, nanoparticle deposits consisting of combinations of Si, Ti, C and N have been explored.

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