Research on deflagration characteristics and thermodynamic mechanism of micron aluminum powders

2021 ◽  
Author(s):  
Ke Yan ◽  
Xiangbao Meng ◽  
Zheng Wang ◽  
Yansong Zhang ◽  
Junfeneg Wang ◽  
...  
Keyword(s):  
Aluminum Powders ◽  
Thermodynamic Mechanism

scholarly journals Self-replication of a quantum artificial organism driven by single-photon pulses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniel Valente
Keyword(s):  
Self Assembly ◽  
Artificial Life ◽  
Single Photon ◽  
Self Organization ◽  
Physical Systems ◽  
Self Organized ◽  
Living Organisms ◽  
A Chain ◽  
Thermodynamic Mechanism ◽  
Self Replication

AbstractImitating the transition from inanimate to living matter is a longstanding challenge. Artificial life has achieved computer programs that self-replicate, mutate, compete and evolve, but lacks self-organized hardwares akin to the self-assembly of the first living cells. Nonequilibrium thermodynamics has achieved lifelike self-organization in diverse physical systems, but has not yet met the open-ended evolution of living organisms. Here, I look for the emergence of an artificial-life code in a nonequilibrium physical system undergoing self-organization. I devise a toy model where the onset of self-replication of a quantum artificial organism (a chain of lambda systems) is owing to single-photon pulses added to a zero-temperature environment. I find that spontaneous mutations during self-replication are unavoidable in this model, due to rare but finite absorption of off-resonant photons. I also show that the replication probability is proportional to the absorbed work from the photon, thereby fulfilling a dissipative adaptation (a thermodynamic mechanism underlying lifelike self-organization). These results hint at self-replication as the scenario where dissipative adaptation (pointing towards convergence) coexists with open-ended evolution (pointing towards divergence).

scholarly journals Oxidation of nano-sized aluminum powders

2016 ◽  
Vol 636 ◽  
pp. 48-56 ◽  
Author(s):  
A.B. Vorozhtsov ◽  
M. Lerner ◽  
N. Rodkevich ◽  
H. Nie ◽  
A. Abraham ◽  
...  
Keyword(s):  
Aluminum Powders

Influence of Different Dispersants on the Dispersion Property of Nano-Aluminium Powders

2011 ◽  
Vol 71-78 ◽  
pp. 122-125 ◽  
Author(s):  
Ling Li Song ◽  
Ren Yuan Zhang ◽  
Ling Bo Mao ◽  
Wen Jie Zhu ◽  
Miao Yan Zheng
Keyword(s):  
Sodium Dodecyl Sulfate ◽  
Ultrasonic Vibration ◽  
Cetyl Trimethyl Ammonium Bromide ◽  
Sodium Dodecyl ◽  
Dispersion Property ◽  
Ammonium Bromide ◽  
Aluminum Powders ◽  
Ultrasonic Time ◽  
Dodecyl Sulfate ◽  
Cetyl Trimethyl Ammonium

The influences of dispersant type, supersonic time and concentration on the dispersion property of the nano-aluminium powders in glycol water were systematically studied by using Sodium dodecyl sulfate (SDS)，cetyl trimethyl ammonium bromide (CTAB) and sodium hexa metah posphate（SHMP）as dispersants. During the first stage of the experiments, influences of dispersant type and ultrasonic time with these dispersants were evaluated. The next stage of the study was focused on SHMP concentration. The influence of SHMP concentration was assessed. The results show that with the increasing of ultrasonic time, the dispersion property of nano-aluminum powders first increases and then decreases, and SHMP is the best one. The excellent dispersing condition on the dispersion property of nano-aluminium is: 5g/L SHMP and 50 min ultrasonic vibration.

Effect of Porosity Content on the Weldability of Powder Metal Parts Produced by Friction Stir Welding

2007 ◽  
Vol 534-536 ◽  
pp. 789-792 ◽  
Author(s):  
Adem Kurt ◽  
Ilyas Uygur ◽  
Hakan Ates
Keyword(s):  
Friction Stir Welding ◽  
Powder Metal ◽  
Aluminum Powders ◽  
Friction Stir ◽  
Metal Parts ◽  
Constant Friction ◽  
Sintered Powder ◽  
Hardness Values ◽  
Welding Technique ◽  
Traveling Speed

Friction stir welding technique (FSW) has many advantages in terms of tool design, rotational speed and traveling speed, and can be adjusted in a precise manner. It enables heat input into the system to be controlled. In this study, Aluminum powders were compacted at 350,400 and 450 MPa pressure and sintered at 450 oC temperature for 30 minutes in Ar atmosphere. Sintered powder metal parts were joined to each other by FSW at the speed of 1800 rpm and traveling welding speed 200 mm/min under a constant friction force. The results show that the amount of porosity affects the weldability of powder metallurgy (P/M) parts. Furthermore, the porosity and microstructural evolution of the Aluminum also affected the hardness values of the tested materials.

Hydrostatic pressing of aluminum powders

1974 ◽  
Vol 13 (12) ◽  
pp. 956-957
Author(s):  
D. M. Karpinos ◽  
B. I. Beresnev ◽  
V. Kh. Kadyrov ◽  
A. G. Kamenetskii ◽  
N. B. Gal'chun
Keyword(s):  
Aluminum Powders

Combustion joinining of carbon/carbon composites by a reactive mixture of titanium and mechanically activated nickel/aluminum powders

2013 ◽  
Vol 39 (7) ◽  
pp. 7499-7505 ◽  
Author(s):  
Ya-Cheng Lin ◽  
Andrey A. Nepapushev ◽  
Paul J. McGinn ◽  
Alexander S. Rogachev ◽  
Alexander S. Mukasyan
Keyword(s):  
Carbon Composites ◽  
Nickel Aluminum ◽  
Aluminum Powders ◽  
Reactive Mixture

scholarly journals Is the Organism a Thermodynamic Mechanism—I

1915 ◽  
Vol 80 (2066supp) ◽  
pp. 82-83
Author(s):  
James Johnstone
Keyword(s):  
Thermodynamic Mechanism

Melting and Oxidation of Nanometer Size Aluminum Powders

2005 ◽  
Vol 896 ◽  
Author(s):  
Mikhaylo A Trunov ◽  
Swati Umbrakar ◽  
Mirko Schoenitz ◽  
Joseph T Mang ◽  
Edward L Dreizin
Keyword(s):  
Particle Size ◽  
Oxidation Behavior ◽  
Melting Behavior ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Scanning Calorimetry ◽  
Aluminum Powders ◽  
Melting Temperatures ◽  
X Ray Scattering ◽  
Powder Samples

AbstractRecently, nanometer-sized aluminum powders became available commercially and their use as potential additives to propellants, explosives, and pyrotechnics has attracted significant interest. It has been suggested that very low melting temperatures are expected for nano-sized aluminum powders and that such low melting temperatures could accelerate oxidation and trigger ignition much earlier than for regular, micron-sized aluminum powders. The objective of this work was to investigate experimentally the melting and oxidation behavior of nano-sized aluminum powders. Powder samples with three different nominal sizes of 44, 80, and 121 nm were provided by Nanotechnologies Inc. The particle size distributions were measured using small angle x-ray scattering. Melting was studied by differential scanning calorimetry where the powders were heated from room temperature to 750 °C in argon environment. Thermogravimetric analysis was used to measure the mass increase indicative of oxidation while the powders were heated in an oxygen-argon gas mixture. The measured melting curves were compared to those computed using the experimental particle size distributions and thermodynamic models describing the melting temperature and enthalpy as functions of the particle size. The melting behavior predicted by different models correlated with the experimental observations only qualitatively. Characteristic step-wise oxidation was observed for all studied nanopowders. The observed oxidation behavior was well interpreted considering the recently established kinetics of oxidation of micron-sized aluminum powders. No correlation was found between the melting and oxidation of aluminum nanopowders.

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