A cost-effective route to produce Al/AlN composites with low coefficient of thermal expansion

2017 ◽  
Vol 51 (20) ◽  
pp. 2845-2851 ◽  
Author(s):  
Kon-Bae Lee ◽  
Seong-Hyeon Yoo ◽  
Yong-Hwan Kim ◽  
Chul-Woong Han ◽  
Sung-Ok Won ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Cost Effective ◽  
Ex Situ ◽  
Nitrogen Gas ◽  
Dispersion Agent ◽  
Al Powder

In this study, a novel process was developed to produce Al/AlN composites by infiltrating molten Al ingot into a mixture of Al and lamp carbon powders. The findings revealed that, during the process, Al2O3 on the surface of Al powder reacted with nitrogen gas and was transformed to AlN. The degree of nitridation was greatly enhanced by adding only less than 3 wt.% lamp carbon, because lamp carbon could act as a dispersion agent as well as a reduction agent. The Al-based composites containing in situ AlN phases showed coefficient of thermal expansion values of ∼11 × 10−6/℃, which were comparable to those of composites containing 60% ex situ AlN particles.

scholarly journals In-situ alloying of AlSi10Mg+Si using Selective Laser Melting to control the coefficient of thermal expansion

2019 ◽  
Vol 795 ◽  
pp. 8-18 ◽  
Author(s):  
Theresa Hanemann ◽  
Luke N. Carter ◽  
Moritz Habschied ◽  
Nicholas J.E. Adkins ◽  
Moataz M. Attallah ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Selective Laser Melting ◽  
Coefficient Of Thermal Expansion ◽  
Laser Melting

3D-Printed Samples For EXLO/INLO Practice and Training

2019 ◽  
Author(s):  
Zachary A. Giannuzzi ◽  
Lucille A. Giannuzzi ◽  
Kathleen A. Gehoski ◽  
William J. Mahoney
Keyword(s):  
3D Printing ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Deliberate Practice ◽  
Cost Effective ◽  
Ex Situ ◽  
Training Samples ◽  
3D Printed ◽  
And Training

Abstract Practice and training samples have been manufactured using 3D-printing methods. These 3D-printed samples mimic the exact geometry of focused ion beam (FIB) prepared specimens and can be used to help master ex situ and in situ lift out micromanipulation methods. An additively manufactured array of samples yields numerous samples needed for repetition and deliberate practice necessary to master the lift out and micromanipulation steps. The 3D-printed samples are cost effective and negates expensive FIB time needed to prepare FIB specimens.

Bioremediation of Oil Contaminated Soil and Water

2015 ◽  
pp. 222-254 ◽  
Author(s):  
Chandrika Malkanthi Nanayakkara ◽  
Ayoma Witharana
Keyword(s):  
Oil Pollution ◽  
Cost Effective ◽  
Ex Situ ◽  
Animal Origin ◽  
Future Research ◽  
Treatment Technology ◽  
Polluted Sites ◽  
Degradation Activity ◽  
Promising Treatment

Pollution from petroleum, plant and animal origin oils, which are released via oil production and shipping operations, refineries, accidental spills, effluents of different industries such as hotels, restaurants, food processing, etc. is ubiquitous in the environment. This necessitates the need for cost effective and efficient remediation technologies. Dealing with the problem chemically and physically is known to generate secondary pollutants and incurs high cost. Expediting natural attenuation via stimulating pollutant degradation activity of residential microbial community and/or introducing competent microflora in to polluted sites has been identified as the most successful and cost effective technology and is termed bioremediation. Phytoremediation, an emerging branch of bioremediation, has also been recognized as a promising treatment technology. Chapter examines the extent of work carried out in in situ and ex situ bioremediation strategies to mitigate oil pollution, the validity of such practices in terms of efficiency of the process and the future research directives.

Laser-Based Diagnostics Applied to the Study of BN Nanotubes Synthesis

2008 ◽  
Vol 8 (11) ◽  
pp. 6129-6140 ◽  
Author(s):  
M. Cau ◽  
N. Dorval ◽  
B. Attal-Trétout ◽  
J. L. Cochon ◽  
B. Cao ◽  
...  
Keyword(s):  
Vapor Phase ◽  
Rayleigh Scattering ◽  
Target Surface ◽  
Boron Nitride Nanotubes ◽  
Ex Situ ◽  
Laser Vaporization ◽  
Condensation Process ◽  
Nitrogen Gas ◽  
Bn Nanostructures

The boron nitride nanotubes (BNNTs) synthesis, using CO2-laser vaporization of a BN target under nitrogen gas, is investigated by UV-laser induced fluorescence (LIF) of the vapor phase and UV-Rayleigh scattering (RS) of the gas-suspended nanoparticles. The LIF signal from B atoms is mainly detected in the 1.5 mm-thick region above the BN target. It originates from a boron-rich vapor region confined near the hot boron droplet formed at the target surface. Then, recombination between hot boron and N2 gas occurs through a fast condensation process as revealed by both the depletion of B atoms from the vapor phase and the RS signal arising from the grown BN nanoparticles. Fluorescence spectra exhibit a strong peak at 250 nm due to boron fluorescence and mainly to nanoparticles Rayleigh scattering. A narrow peak is observed at 210 nm and a broader peak at 189 nm. These bands are tentatively assigned to fluorescence or photoluminescence (PL) from gaseous or solid BN species respectively since both gas and solid phases coexist in the plume due to the rapid cooling process. Two very weak bands occur at 308 nm and 350 nm. They are related to PL of defects bands from BN nanostructures on the basis of ex situ PL spectra of h-BN crystallites and multi-wall BNNTs. Detection of oxygen impurities is shown feasible through LIF from BO radical which is detected just above the BN target evaporated under vacuum pressure (∼1 mbar). An optical diagnosticstrategy is demonstrated from these first in situ observations during BNNTs synthesis.

Bioremediation of Oil Contaminated Soil and Water

Biotechnology ◽  
2019 ◽  
pp. 2090-2122
Author(s):  
Chandrika Malkanthi Nanayakkara ◽  
Ayoma Witharana
Keyword(s):  
Oil Pollution ◽  
Cost Effective ◽  
Ex Situ ◽  
Animal Origin ◽  
Future Research ◽  
Treatment Technology ◽  
Polluted Sites ◽  
Degradation Activity ◽  
Promising Treatment

Pollution from petroleum, plant and animal origin oils, which are released via oil production and shipping operations, refineries, accidental spills, effluents of different industries such as hotels, restaurants, food processing, etc. is ubiquitous in the environment. This necessitates the need for cost effective and efficient remediation technologies. Dealing with the problem chemically and physically is known to generate secondary pollutants and incurs high cost. Expediting natural attenuation via stimulating pollutant degradation activity of residential microbial community and/or introducing competent microflora in to polluted sites has been identified as the most successful and cost effective technology and is termed bioremediation. Phytoremediation, an emerging branch of bioremediation, has also been recognized as a promising treatment technology. Chapter examines the extent of work carried out in in situ and ex situ bioremediation strategies to mitigate oil pollution, the validity of such practices in terms of efficiency of the process and the future research directives.

scholarly journals In situ organic Fenton-like catalysis triggered by anodic polymeric intermediates for electrochemical water purification

2020 ◽  
Vol 117 (49) ◽  
pp. 30966-30972
Author(s):  
Dan-Ni Pei ◽  
Chang Liu ◽  
Ai-Yong Zhang ◽  
Xiao-Qiang Pan ◽  
Han-Qing Yu
Keyword(s):  
Water Purification ◽  
Cost Effective ◽  
Ex Situ ◽  
Pollutant Degradation ◽  
Secondary Pollution ◽  
Redox Active ◽  
Pollution Problem ◽  
Catalytic Stability ◽  
Phenol Conversion

Organic Fenton-like catalysis has been recently developed for water purification, but redox-active compounds have to be ex situ added as oxidant activators, causing secondary pollution problem. Electrochemical oxidation is widely used for pollutant degradation, but suffers from severe electrode fouling caused by high-resistance polymeric intermediates. Herein, we develop an in situ organic Fenton-like catalysis by using the redox-active polymeric intermediates, e.g., benzoquinone, hydroquinone, and quinhydrone, generated in electrochemical pollutant oxidation as H2O2activators. By taking phenol as a target pollutant, we demonstrate that the in situ organic Fenton-like catalysis not only improves pollutant degradation, but also refreshes working electrode with a better catalytic stability. Both1O2nonradical and ·OH radical are generated in the anodic phenol conversion in the in situ organic Fenton-like catalysis. Our findings might provide a new opportunity to develop a simple, efficient, and cost-effective strategy for electrochemical water purification.

scholarly journals Experimental determination of precision, resolution, accuracy and trueness of time-of-flight neutron diffraction strain measurements

2020 ◽  
Vol 53 (2) ◽  
pp. 494-511
Author(s):  
I. C. Noyan ◽  
J. R. Bunn ◽  
M. K. Tippett ◽  
E. A. Payzant ◽  
B. Clausen ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Lattice Strain ◽  
Coefficient Of Thermal Expansion ◽  
Time Of Flight ◽  
Temperature Changes ◽  
Strain Measurements ◽  
Simple Statistical Analysis ◽  
Quantities Of Interest

A simple statistical analysis which yields the precision, resolution, accuracy and trueness of diffraction-based lattice strain measurements is discussed. The procedure consists of measuring the thermal expansion induced in each component of an ideal non-reacting two-component crystalline powder sample in situ. One component, with a high coefficient of thermal expansion (CTE), serves as an internal thermometer. The quantities of interest are obtained by determining the smallest statistically significant thermal lattice strain which can be detected through diffraction analysis in the second, low-CTE, component in response to controlled temperature changes. This procedure also provides a robust check of the alignment of the diffraction system and is able to reveal the presence of systematic errors. The application of this technique to a time-of-flight engineering diffractometer/strain scanner is presented.

Preparation of solution-processable colorless polyamide-imides with extremely low thermal expansion coefficients through an in-situ silylation method for potential space optical applications

e-Polymers ◽  
2016 ◽  
Vol 16 (5) ◽  
pp. 395-402 ◽  
Author(s):  
Song Wang ◽  
Guangjie Yang ◽  
Shibin Wu ◽  
Ge Ren ◽  
Wei Yang ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Linear Chain ◽  
Tensile Modulus ◽  
Optical Homogeneity ◽  
One Pot ◽  
System Architectures ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion

AbstractSeveral tough and flexible fluorinated polyamide-imide films were prepared from trimellitic anhydride chloride and 2,2′-bis(trifluoromethyl)benzidine through a facile one-pot in-situ silylation method. By incorporating fluorinated side groups, the solubility of the prepared polyamide-imide was greatly enhanced. Meanwhile, due to their linear chain configuration and the existence of hydrogen bonding, the prepared polyamide-imide films revealed high tensile strength, high tensile modulus, high glass transition temperature (Tg) and most interestingly, very low coefficient of thermal expansion (CTE) of 11 ppm/°C. Copolymerization with pyromellitic dianhydride (PMDA) led to an extremely low CTE of 4 ppm/°C which should be among the lowest values available for soluble polyamide-imides. The optical homogeneity and stress homogeneity of the obtained polyamide-imide films were also tested. After non-contact with substance and thermal treatment at 300°C, they revealed a better optical homogeneity and stress homogeneity than that of the commercially available Kapton polyimide (PI) films, with a PV value of 0.915 λ and RMS value of 0.163 λ. Thus, these colorless and soluble polyamide-imide films simultaneously possessing promising optical imaging performance are good candidates as novel diffractive membrane optical system architectures.

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