Application of Overdriven Gaseous Detonation for Spraying

1998 ◽  
Author(s):  
T.P. Gavrilenko ◽  
Y.A. Nikolaev ◽  
V.Y. Ulianitsky
Keyword(s):  
Surface Coating ◽  
Internal Surface ◽  
Gaseous Detonation ◽  
Detonation Waves ◽  
Powder Materials ◽  
High Melting ◽  
Detonation Products ◽  
Detonation Spraying ◽  
High Melting Temperature ◽  
Overdriven Detonation

Abstract The use of overdriven detonation waves can promote coating fabrication from powder materials with high melting temperature and improve the quality coating for all materials. The detonation products flow behind overdriven detonation has kinetic and thermal energy values significantly exceeding those for self-sustaining Chapman- Jouguet's detonation, conventionally used for detonation spraying. This makes it possible to design a micro-gun and, as a consequence, the equipment for internal surface coating.

Quasi-One-Dimentional Approach To Modeling Of Propagation Of Gas Detonation In A Medium With Variable Chemical Composition

2015 ◽  
Vol 10 (4) ◽  
pp. 77-84
Author(s):  
Evgeniy Prokhorov
Keyword(s):  
Chemical Composition ◽  
Heat Removal ◽  
Detonation Waves ◽  
Detonation Products ◽  
Gas Detonation ◽  
One Dimensional ◽  
Chemical Agents ◽  
Variable Chemical ◽  
Detonation Transition ◽  
Overdriven Detonation

The quasi-one-dimensional model is presented to describe the propagation of detonation wave in a tube filled with an explosive gas mixture, the chemical composition of which varies along the tube axis. This takes into account energy losses chemical equilibrium flow of detonation products for friction and heat removal in the tube wall. Within the limits of this model, it numerically investigated the gas detonation transition through a region with the concentration gradient of chemical agents. It analyzed the possibility of excitation overdriven detonation waves as a result of this transition.

Computational Code for Detonation Spraying Process

1998 ◽  
Author(s):  
T.P. Gavrilenko ◽  
Y.A. Nikolaev ◽  
V.Y. Ulianitsky ◽  
M.C. Kim ◽  
J.W. Hong
Keyword(s):  
Gaseous Mixture ◽  
Gaseous Detonation ◽  
Powder Injection ◽  
Powder Materials ◽  
Productivity Analysis ◽  
Detonation Spraying ◽  
Injection Point ◽  
High Productivity ◽  
Product Flow ◽  
Computational Code

Abstract Interactive Computational Code is presented that provides a high-productivity analysis of the complex detonation spraying technology. It is based on exact gas dynamics theory taking into account chemical reactions for description of the gaseous detonation phenomena. It deals with specific features of the process like non-homogeneity of gaseous mixture compositions due to gas filling operation and powder injection into the barrel. Acceleration and heating of powder particles by the detonation product flow were simulated including particle melting, fragmentation and vaporization. Calculations for different fuels and powder materials were accomplished. Optimum conditions (gas mixture, barrel length, powder injection point, etc.) to provide highest velocity and appropriate temperature for typical metal and cermet powders are discussed. The conditions for coating formation by the detonation gun «Ob» were established and samples were produced. Experimental data on detonation coating properties are presented to prove the theoretical results.

A Tem Study of Slip Systems in MoSi2/WSi2 Alloys

1991 ◽  
Vol 49 ◽  
pp. 942-943
Author(s):  
Stuart A. Maloy
Keyword(s):  
Solid Solution ◽  
Solid Solution Hardening ◽  
Slip Systems ◽  
High Melting ◽  
Group 14 ◽  
Solution Hardening ◽  
Brittle To Ductile Transition ◽  
High Melting Temperature ◽  
Tetragonal Unit Cell ◽  
Structural Applications

MoSi2 has recently been investigated as a potential material for high temperature structural applications. It has excellent oxidation resistance up to 1700°C, a high melting temperature, 2030°C, and a brittle-to-ductile transition temperature at 900-1000°C. WSi2 is isomorphous with MoSi2 and has a body-centered tetragonal unit cell of the space group 14/mmm. The lattice parameters are a=3.20 Å and c=7.84 Å for MoSi2 and a=3.21 Å and c=7.88 Å for WSi2. Therefore, WSi2 was added to MoSi2 to improve its strength via solid solution hardening. The purpose of this study was to investigate the slip systems in polycrystalline MoSi2/WSi2 alloys.

Sustainable Chiral Polyamides with High Melting Temperature via Enhanced Anionic Polymerization of a Menthone-Derived Lactam

2016 ◽  
Vol 37 (10) ◽  
pp. 851-857 ◽  
Author(s):  
Malte Winnacker ◽  
Michael Neumeier ◽  
Xiaohan Zhang ◽  
Christine M. Papadakis ◽  
Bernhard Rieger
Keyword(s):  
Melting Temperature ◽  
Anionic Polymerization ◽  
High Melting ◽  
High Melting Temperature

scholarly journals Structure and Stability of a Dimeric G-Quadruplex Formed by Cyclic Oligonucleotides

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Joan Casals ◽  
Júlia Viladoms ◽  
Enrique Pedroso ◽  
Carlos González
Keyword(s):  
Telomeric Repeat ◽  
High Melting ◽  
Structure And Stability ◽  
Dimeric Structure ◽  
Nmr Data ◽  
High Melting Temperature ◽  
Sodium Nmr ◽  
G Quadruplex ◽  
Global Topology ◽  
Quadruplex Formation

We have studied the structure and stability of the cyclic dodecamer d<pGGGTTAGGGTTA>, containing two copies of the human telomeric repeat. In the presence of sodium, NMR data are consistent with a dimeric structure of the molecule in which two cycles self-associate forming a quadruplex with three guanine tetrads connected by edgewise loops. The two macrocycles are arranged in a parallel way, and the dimeric structure exhibits a high melting temperature. These results indicate that cyclization of the phosphodiester chain does not prevent quadruplex formation, although it affects the global topology of the quadruplex.

Application of atmospheric CVD for internal surface coating of graphite conduit by silicon carbide

2015 ◽  
Vol 456 ◽  
pp. 200-205 ◽  
Author(s):  
P.T. Rao ◽  
U. Jain ◽  
P.K. Mollick ◽  
A. Agarwal ◽  
J.K. Chakravartty ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Surface Coating ◽  
Internal Surface

scholarly journals Isolation of RNA from a mixture and its detection by utilizing a microgel-based optical device

2018 ◽  
Vol 96 (12) ◽  
pp. 1079-1086 ◽  
Author(s):  
Molla R. Islam ◽  
Shakiba Azimi ◽  
Faranak Teimoory ◽  
Glen Loppnow ◽  
Michael J. Serpe
Keyword(s):  
Melting Temperature ◽  
Magnetic Beads ◽  
Colorimetric Detection ◽  
Optical Devices ◽  
High Melting ◽  
Dna Duplex ◽  
Dna And Rna ◽  
High Melting Temperature ◽  
Hybrid Duplex ◽  
Fluorescent Studies

In this investigation, we show that RNA can be separated from a solution containing DNA and RNA and the isolated RNA can be detected using poly (N-isopropylacrylamide-co-N-(3-aminopropyl) methacrylamide hydrochloride) microgel-based optical devices (etalons). The isolation of RNA was accomplished by using hairpin-functionalized magnetic beads (MMPDNA) and differential melting, based on the fact that the DNA–RNA hybrid duplex is stronger (i.e., high melting temperature) than the DNA–DNA duplex (i.e., low melting temperature). By performing concurrent etalon sensing and fluorescent studies, we found that the MMPDNA combined with differential melting was capable of selectively separating RNA from DNA. This selective separation and simple colorimetric detection of RNA from a mixture will help lead to future RNA-based disease diagnostic devices.

Analysis of steel-with-composite material substitution in military vehicle hull floors subjected to shallow-buried landmine-detonation loads

2014 ◽  
Vol 10 (3) ◽  
pp. 416-448 ◽  
Author(s):  
M. Grujicic ◽  
J.S. Snipes ◽  
S. Ramaswami ◽  
R. Yavari ◽  
C.-F. Yen ◽  
...  
Keyword(s):  
Composite Material ◽  
Soil Surface ◽  
Gaseous Detonation ◽  
Detonation Products ◽  
Content Type ◽  
Material Substitution ◽  
Reinforced Polymer ◽  
Military Vehicle ◽  
Constitutive Response ◽  
Continuum Structure

Purpose – The purpose of this paper is to address the problem of substitution of steel with fiber-reinforced polymer-matrix composite in military-vehicle hull-floors, and identifies and quantifies the associated main benefits and shortcomings. Design/methodology/approach – The problem is investigated using a combined finite-element/discrete-particle computational analysis. Within this analysis, soil (in which a landmine is buried), gaseous detonation products and air are modeled as assemblies of discrete, interacting particles while the hull-floor is treated as a Lagrangian-type continuum structure. Considerable effort has been invested in deriving the discrete-material properties from the available experimental data. Special attention has been given to the derivation of the contact properties since these, in the cases involving discrete particles, contain a majority of the information pertaining to the constitutive response of the associated materials. The potential ramifications associated with the aforementioned material substitution are investigated under a large number of mine-detonation scenarios involving physically realistic ranges of the landmine mass, its depth of burial in the soil, and the soil-surface/floor-plate distances. Findings – The results obtained clearly revealed both the benefits and the shortcomings associated with the examined material substitution, suggesting that they should be properly weighted in each specific case of hull-floor design. Originality/value – To the authors’ knowledge, the present work is the first public-domain report of the findings concerning the complexity of steel substitution with composite-material in military-vehicle hull-floors.

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