scholarly journals Microwave interrogation of an air plasma plume as a model system for hot spots in explosives

2017 ◽  
Author(s):  
Ronald J. Kane ◽  
Joseph W. Tringe ◽  
Gregory L. Klunder ◽  
Emer V. Baluyot ◽  
John M. Densmore ◽  
...  
Keyword(s):  
Hot Spots ◽  
Plasma Plume ◽  
Model System ◽  
Air Plasma

Influence of Air Plasma Spraying Process Parameters on Ceramic Layer in Thermal Barrier Coatings

2017 ◽  
Vol 267 ◽  
pp. 207-211
Author(s):  
Tadeusz Kubaszek ◽  
Marek Góral
Keyword(s):  
Plasma Spraying ◽  
Process Parameters ◽  
Plasma Plume ◽  
Ceramic Powder ◽  
Ceramic Coatings ◽  
Air Plasma ◽  
Fine Grain ◽  
Contour Plots ◽  
Molten Particle ◽  
Sprayed Coating

The aim of this study was to examine the possibility of application in APS process Yttria Stabilized Zirconia (YSZ) – Metco 6700 ceramic powder normally used in Low Pressure Plasma Spraying (LPPS) method. Powder grain size is around 10 µm. Parameters such as chemical composition of plasma gases and current were changed to obtain the best result. The experiment was divided into two stages. Firstly, temperature, velocity and size of a molten particle of ceramic powder inside plasma plume were measured via DPV eVolution equipment (TECNAR company) during a different set of process parameters. Plasma plume was also scanned to obtain cross-section contour plots of mentioned properties of the molten particle. Secondly, the same processes were repeated to deposit TBC coatings onto sheet metal to examine the structure.The obtained results showed that it is possible to use fine-grain YSZ powder Metco 6700 for APS process. Obtained ceramic coatings had a thickness from 100 to 240 µm. The plasma sprayed coating was characterised by a smooth surface. The measurement of spraying parameters showed the uniform temperature, velocity and particle size of the powder inside plasma plume.

A Touchable Pulsed Air Plasma Plume Driven by DC Power Supply

2010 ◽  
Vol 38 (12) ◽  
pp. 3404-3408 ◽  
Author(s):  
ShuQun Wu ◽  
XinPei Lu ◽  
ZiLan Xiong ◽  
Yuan Pan
Keyword(s):  
Power Supply ◽  
Plasma Plume ◽  
Air Plasma ◽  
Dc Power ◽  
Dc Power Supply

Oxidation Control in Atmospheric Plasma Spraying: Comparison Between Ar/H2/He and Ar/H2 Mixtures

1998 ◽  
Author(s):  
A. Denoirjean ◽  
O. Lagnoux ◽  
P. Fauchais ◽  
V. Sember
Keyword(s):  
Plasma Spraying ◽  
Flow Model ◽  
Plasma Plume ◽  
Air Entrainment ◽  
Thermomechanical Properties ◽  
Plasma Jets ◽  
Atmospheric Plasma ◽  
Air Plasma ◽  
Air Plasma Spraying ◽  
Enthalpy Probe

Abstract Plasma spraying of metals and metallic alloys performed in controlled atmosphere or soft vacuum results in coatings with a low oxidation level and excellent thermomechanical properties. Unfortunately, the spraying cost is drastically increased by one or two orders of magnitude compared to air plasma spraying (APS). Thus the minimisation of oxidation during APS is a key issue for the development of such coatings. Oxygen concentrations sucked into plasma jets have been measured by an enthalpy probe linked to a mass spectrometer. This technique allows to determine simultaneously plasma composition, temperature and velocity distributions within the plasma plume. Results have been compared to those obtained with a two-dimensional turbulent flow model. The obtained results have shown that surrounding air entrainment is reduced when using adequate Ar/Hj/He mixtures which viscosity is higher than that of Ar/H, mixtures, limiting the turbulence in the jet fringes and pumping of the surrounding atmosphere.

A uniform laminar air plasma plume with large volume excited by an alternating current voltage

2015 ◽  
Vol 24 (6) ◽  
pp. 065020 ◽  
Author(s):  
Xuechen Li ◽  
Wenting Bao ◽  
Jingdi Chu ◽  
Panpan Zhang ◽  
Pengying Jia
Keyword(s):  
Large Volume ◽  
Plasma Plume ◽  
Alternating Current ◽  
Air Plasma ◽  
Current Voltage

scholarly journals Пространственное распределение температуры газа в воздушной плазменной струе тлеющего микроразряда постоянного тока

2018 ◽  
Vol 44 (18) ◽  
pp. 77
Author(s):  
О.М. Степанова ◽  
А.В. Казак ◽  
А.М. Астафьев ◽  
М.Э. Пинчук ◽  
Л.В. Симончик
Keyword(s):  
Room Temperature ◽  
Plasma Plume ◽  
Outer Region ◽  
Ambient Air ◽  
Gas Temperature ◽  
Air Plasma ◽  
Air Flow Rate ◽  
Thermocouple Probe ◽  
Discharge Cell ◽  
Hot Zone

AbstractThe spatial distribution of gas temperature in air plasma jet of dc glow microdischarge has been determined. The temperature field was measured by a thermocouple probe and compared to schlieren images. The jet can be separated in the radial direction into three characteristic regions with clearly pronounced boundaries. The central region represents a narrow hot zone corresponding to the visible plasma plume, in which the gas temperature varies from 50 to 200°C depending on the air flow rate and distance from the anode. This zone is surrounded by a warm “coat” of ~1-cm diameter and a temperature within 30–50°C. The outer region represented ambient air at room temperature. The zone of temperatures above 50°C did not extend to a distance above 3 cm from the output nozzle of the discharge cell.

A Protozoan Model for Golgi-Associated Calcification

1971 ◽  
Vol 29 ◽  
pp. 332-333
Author(s):  
D. C. Williams ◽  
D. E. Outka
Keyword(s):  
Golgi Apparatus ◽  
Organic Matrix ◽  
Model System ◽  
Sequential Formation

Many studies have shown that the Golgi apparatus is involved in a variety of synthetic activities, and probably no Golgi product is more elaborate than the scales produced by various kinds of phytoflagellates. The formation of calcified scales (coccoliths, Fig. 1,2) of the coccolithophorid phytoflagellates provides a particularly interesting model system for the study of biological mineralization, and the sequential formation of Golgi products.The coccoliths of Hymenomonas carterae consist of a scale-like base (Fig. 2 and 4, b) with a highly structured calcified (CaCO3) rim composed of two distinct elements which alternate about the base periphery (Fig. 1 and 3, A, B). Each element is enveloped by a sheath-like organic matrix (Fig. 3; Fig. 4, m).

Existence of DNA in yeast microbodies

1978 ◽  
Vol 36 (2) ◽  
pp. 232-233
Author(s):  
Masako Osumi ◽  
Misuzu Nagano ◽  
Hiroko Kazama
Keyword(s):  
Catalase Activity ◽  
Buoyant Density ◽  
Model System ◽  
Contour Length ◽  
Native State ◽  
Normal Alkane ◽  
Remarkable Increase ◽  
Dna Molecule ◽  
Mitochondrial Dnas

We have found that microbodies appeared profusely together with a remarkable increase in catalase activity in normal alkane-grown cells of hydrocarbon-utilizing Candida yeasts, and that the microbodies multiplied by division in these cells. These features of Candida yeasts seem to provide a useful model system for studies on the biogenesis of the microbody. Subsequently, we have succeeded in isolation of Candida microbodies in an apparently native state, as judged biochemically and morphologically. The presence of DNA in the purified microbody fraction thus obtained was proved by the diphenylamine method. DNA molecule of about 15 urn in contour length was released from an isolated microbody. The physicochemical analyses of the microbody DNA revealed that its buoyant density differed from nuclear and mitochondrial DNAs. All these results lead us to the possibility that there is a novel type of DNA in microbodies.

The coprecipitation of Cr3P and Cr in Cu

1988 ◽  
Vol 46 ◽  
pp. 764-765
Author(s):  
M.J. Witcomb ◽  
U. Dahmen ◽  
K.H. Westmacott
Keyword(s):  
Orientation Relationship ◽  
Interface Structure ◽  
Model System ◽  
Relative Orientation ◽  
Age Hardening ◽  
Precipitation Behavior ◽  
Solution Treated ◽  
Small Needle ◽  
Diffraction Patterns ◽  
Interface Structures

Cu-Cr age-hardening alloys are of interest as a model system for the investigation of fcc/bcc interface structures. Several past studies have investigated the morphology and interface structure of Cr precipitates in a Cu matrix (1-3) and good success has been achieved in understanding the crystallography and strain contrast of small needle-shaped precipitates. The present study investigates the effect of small amounts of phosphorous on the precipitation behavior of Cu-Cr alloys.The same Cu-0.3% Cr alloy as was used in earlier work was rolled to a thickness of 150 μm, solution treated in vacuum at 1050°C for 1h followed by quenching and annealing for various times at 820 and 863°C.Two laths and their corresponding diffraction patterns in an alloy aged 2h at 820°C are shown in correct relative orientation in Fig. 1. To within the limit of accuracy of the diffraction patterns the orientation relationship was that of Kurdjumov-Sachs (KS), i.e. parallel close-packed planes and directions.

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

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