Fabrication of near-net-shape Al2O3-fiber-reinforced Ni3Al composites by combustion synthesis

1995 ◽  
Vol 10 (7) ◽  
pp. 1736-1745 ◽  
Author(s):  
William C. Williams ◽  
Gregory C. Stangle
Keyword(s):  
Combustion Synthesis ◽  
Low Temperatures ◽  
Low Cost ◽  
Matrix Material ◽  
Scale Up ◽  
Synthesis Process ◽  
Fiber Reinforced ◽  
Al2o3 Fiber ◽  
Near Net Shape ◽  
Short Time

In this paper, a one-step, combustion synthesis-based process for fabricating Al2O3 fiber-reinforced Ni3Al is described. The process uses relatively low temperatures and pressures, and can be used to prepare relatively large, dense, near-net-shape articles that possess either simple or relatively complicated shapes. This process can be used to incorporate continuous, aligned fibers into the Ni3Al matrix material in such a way that the fibers are not damaged either mechanically (due to relatively small loads applied during the process) or chemically (due to the very short time at which the sample remains at elevated tempertures during the process). (Chopped fibers, as well as equiaxed particles or whiskers, could also be similarly incorporated using this process.) This combustion synthesis process is a relatively simple one-requiring only relatively low temperatures and pressures, as well as relatively low-cost starting materials-which suggests that its scale-up beyond the laboratory scale would be particularly straightforward.

scholarly journals Short Time and Low Temperature Reaction between Metal Oxides through Microwave-Assisted Hydrothermal Method

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
S. M. V. Novais ◽  
P. C. R. Silva ◽  
Z. S. Macedo ◽  
L. B. Barbosa
Keyword(s):  
Low Temperatures ◽  
Hydrothermal Reaction ◽  
Low Cost ◽  
Broad Emission Band ◽  
Time Saving ◽  
Cadmium Tungstate ◽  
Microwave Assisted ◽  
Solid State Route ◽  
Broad Emission ◽  
Short Time

This work demonstrates the possibility of synthesis of cadmium tungstate at low temperatures using oxide precursors. Cadmium tungstate (CdWO4) scintillator was produced via microwave-assisted hydrothermal reaction using the precursors CdO and WO3. The methodology was based on microwave radiation for heating, which is remarkably faster than the solid-state route or conventional hydrothermal procedure. CdWO4 monoclinic (wolframite) structure was successfully obtained at 120°C for synthesis times as short as 20 min. This route does not require the use of templates or surfactants and yields self-assembled nanorods with size of around 24 ± 9 nm width and 260 ± 47 nm length. The growth mechanism for the formation of CdWO4 involves microwave-induced dissociation of the reagents and solvation of Cd2+ and WO42- ions, which are free to move and start the nucleation process. The luminescence properties of the produced nanoparticles were investigated, presenting a broad emission band at around 500 nm, which is comparable to that observed for samples produced using other chemical routes. This result highlights the great potential of the proposed method as a low-cost and time saving process to fabricate luminescent oxide nanoparticles.

Grain Enhancement of Thin Silicon Layers Using Optical Processing

1997 ◽  
Vol 470 ◽  
Author(s):  
B. L. Sopori ◽  
Jeff Alleman ◽  
W. Chen ◽  
T. Y. Tan ◽  
N. M. Ravindra
Keyword(s):  
Thin Films ◽  
Low Temperatures ◽  
Low Cost ◽  
Optical Processing ◽  
Glass Substrates ◽  
Coated Substrate ◽  
Grain Sizes ◽  
Fine Grain ◽  
A New Technique ◽  
Short Time

ABSTRACTWe describe a new technique for producing large-grain, poly-Si thin films on low-cost glass substrates for solar cell applications. A layer of fine-grain poly-Si is deposited on metal-coated substrate followed by a grain enhancement using optical/thermal annealing at low temperatures (∼ 500 °C). The results show that in thin-layer silicon, less than 3 microns, grains can be formed in a short time (few minutes) with grain sizes larger than the film thickness. The possible mechanisms involved in this process are also presented.

Ultrasonic-Impregnation for Fiber-Reinforced Thermoplastic Prepreg Production

2017 ◽  
Vol 742 ◽  
pp. 17-24
Author(s):  
Steve Sockol ◽  
Christoph Doerffel ◽  
Juliane Mehnert ◽  
Gerd Zwinzscher ◽  
Steffen Rein ◽  
...  
Keyword(s):  
Large Scale ◽  
Matrix Material ◽  
Scale Up ◽  
Small Scale ◽  
Hydraulic Pressure ◽  
Scale Production ◽  
Fiber Reinforced ◽  
Technological Parameters ◽  
Ultrasonic Technology ◽  
High Processing

Fiber-reinforced thermoplastics have a high potential for big scale light weight process applications due to low processing times and recyclability. Further advantages are the low emissions during the manufacturing process and beneficial handling and storing properties of the semi finished materials. Thermoplastic composites are made of reinforcement fibers and a thermoplastic polymer matrix by applying two essential sub processes: (1) melting of the matrix-material and (2) impregnating the textile component with molten matrix-material. At present state of art both sub-processes are applied by using double-belt-presses, characterized by high processing temperatures and high processing forces. Therefore, a large amount of energy is needed to create the necessarily high compaction forces and temperatures with hydraulic cylinders and electric heating. Convection, infrared-radiation and the cooling (dynamic) of tempered machine parts leads to a significant dissipation of energy. Especially the process for generating the hydraulic pressure has a low level of efficiency. Therefore, in respect to economic and ecologic reasons, novel energy-efficient impregnation processes need to be investigated and developed. The represented novel impregnation process is based on ultrasonic technology. A stack of polymer film (outer layers) and a textile ply (inner layer) is formed and the energy is applied with an ultrasonic sonotrode. The efficient, fast and strongly concentrated energy application into the thermoplastic films allows the development of novel and highly flexible machine concepts. These can be used for development of small scale up to large scale production processes. The ultrasonic-technology allows a continuous impregnation of the textile component with molten matrix-material. A custom-designed prototype was developed. First material samples were produced and the technological parameters studied. A characterization of the experimental results, material samples, prototype machine and process is the focus of this paper.

scholarly journals One Pot Synthesis, Surface and Magnetic Properties of Cu2O/Cu and Cu2O/CuO Nanocomposites

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 751
Author(s):  
Sameerah I. Al-Saeedi ◽  
Ghadah M. Al-Senani ◽  
Omar H. Abd-Elkader ◽  
Nasrallah M. Deraz
Keyword(s):  
Magnetic Properties ◽  
Low Cost ◽  
Synthesis Process ◽  
Transmission Electron Micrograph ◽  
One Pot ◽  
One Pot Synthesis ◽  
Auto Combustion ◽  
Product Displays ◽  
Short Time ◽  
Adsorption Desorption

A series of copper-based systems containing two different nanocomposites (Cu2O/CuO and Cu2O/Cu) was synthesized by the egg white assisted auto-combustion route. This method was distinguished by the simplicity of its steps, low cost, one-pot synthesis process at low temperature and, short time. The characterization of the as prepared nanocomposites was carried out by using X-ray diffraction (XRD), Fourier-transform infrared (FTIR), Scanning electron microscope (SEM) and transmission electron micrograph (TEM), Energy dispersive spectrometry (EDS) techniques. Surface and magnetic properties of the obtained systems were determined by using N2 adsorption/desorption isotherms at 77 K and the vibrating sample magnetometer (VSM) technique. XRD results confirmed the formation of Cu2O/CuO and Cu2O/Cu nanocomposites with different ratios of well crystalline CuO, Cu2O, and Cu phases. FTIR results of the combusted product displays the presence of both CuO and Cu2O, respectively. SEM/EDS and TEM results confirm the formation of a porous nanocomposite containing Cu, O, and C elements. The change in concentration of the oxygen vacancies at the surface or interface of both Cu2O/CuO and Cu2O/Cu nanoparticles resulted in different changes in their magnetization. Based on this study, it is possible to obtain nanocomposite-based copper with multiple valances by a simple and inexpensive route which can be suitable for the fabrication of different transition metal composites.

Low-Cost Hardware Implementation of Human Blood Identification Device Using Feed-Forward Artificial Neural Network on FPGA

2018 ◽  
Author(s):  
Rizki Eka Putri ◽  
Denny Darlis
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Low Cost ◽  
Image Resolution ◽  
Blood Type ◽  
Feed Forward ◽  
Testing Facility ◽  
System Input ◽  
Artificial Neural ◽  
Short Time

This article was under review for ICELTICS 2018 -- In the medical world there is still service dissatisfaction caused by lack of blood type testing facility. If the number of tested blood arise, a lot of problems will occur so that electronic devices are needed to determine the blood type accurately and in short time. In this research we implemented an Artificial Neural Network on Xilinx Spartan 3S1000 Field Programable Gate Array using XSA-3S Board to identify the blood type. This research uses blood sample image as system input. VHSIC Hardware Discription Language is the language to describe the algorithm. The algorithm used is feed-forward propagation of backpropagation neural network. There are 3 layers used in design, they are input, hidden1, and output. At hidden1layer has two neurons. In this study the accuracy of detection obtained are 92%, 92%, 92%, 90% and 86% for 32x32, 48x48, 64x64, 80x80, and 96x96 pixel blood image resolution, respectively.

Low Temperature Fault Isolation Using Soft Defect Localization

2012 ◽  
Author(s):  
Kristopher D. Staller
Keyword(s):  
Low Temperatures ◽  
Laser Scanning ◽  
Low Cost ◽  
Fault Isolation ◽  
Laser Scanning Microscopy ◽  
Cold Temperature ◽  
Multiple Point ◽  
Defect Localization ◽  
Low Levels

Abstract Cold temperature failures are often difficult to resolve, especially those at extreme low levels (< -40°C). Momentary application of chill spray can confirm the failure mode, but is impractical during photoemission microscopy (PEM), laser scanning microscopy (LSM), and multiple point microprobing. This paper will examine relatively low-cost cold temperature systems that can hold samples at steady state extreme low temperatures and describe a case study where a cold temperature stage was combined with LSM soft defect localization (SDL) to rapidly identify the cause of a complex cold temperature failure mechanism.

Robust Test Method of TSOP PEMs for Space Application

2019 ◽  
Author(s):  
Yasunobu Iwai ◽  
Koichi Shinozaki ◽  
Daiki Tanaka
Keyword(s):  
Evaluation Method ◽  
Low Cost ◽  
Reliability Evaluation ◽  
Test Method ◽  
Thermal Shock Test ◽  
Space Application ◽  
Space Applications ◽  
Limit Test ◽  
Long Time ◽  
Short Time

Abstract Compared with space parts, consumer parts are highly functional, low cost, compact and lightweight. Therefore, their increased usage in space applications is expected. Prior testing and evaluation on space applicability are necessary because consumer parts do not have quality guarantees for space application [1]. However, in the conventional reliability evaluation method, the test takes a long time, and the problem is that the robustness of the target sample can’t be evaluated in a short time. In this report, we apply to the latest TSOP PEM (Thin Small Outline Package Plastic Encapsulated Microcircuit) an evaluation method that combines preconditioning and HALT (Highly Accelerated Limit Test), which is a test method that causes failures in a short time under very severe environmental conditions. We show that this method can evaluate the robustness of TSOP PEMs including solder connections in a short time. In addition, the validity of this evaluation method for TSOP PEM is shown by comparing with the evaluation results of thermal shock test and life test, which are conventional reliability evaluation methods.

Constructive Optimisation of the Propeller Type Mixing Devices Using the Virtual and Rapid Prototyping

2017 ◽  
Vol 68 (3) ◽  
pp. 453-458 ◽  
Author(s):  
Daniel Besnea ◽  
Alina Spanu ◽  
Iuliana Marlena Prodea ◽  
Gheorghita Tomescu ◽  
Iolanda Constanta Panait
Keyword(s):  
Rapid Prototyping ◽  
Low Cost ◽  
Scale Up ◽  
Three Dimensional ◽  
Rapid Identification ◽  
Multidisciplinary Optimization ◽  
External Diameter ◽  
Process Industries ◽  
Parametric Cad ◽  
Shaft Torque

The paper points out the advantages of rapid prototyping for improving the performances/constructive optimization of mixing devices used in process industries, here exemplified to propeller types ones. The multidisciplinary optimization of the propeller profile affords its design using parametric CAD methods. Starting from the mathematical curve equations proposed for the blade profile, it was determined its three-dimensional virtual model. The challenge has been focused on the variation of propeller pitch and external diameter. Three dimensional ranges were manufactured using the additive manufacturing process with Marker Boot 3D printer. The mixing performances were tested on the mixing equipment measuring the minimum rotational speed and the correspondent shaft torque for complete suspension achieved for each of the three models. The virtual and rapid prototyping method is newly proposed by the authors to obtain the basic data for scale up of the mixing systems, in the case of flexible production (of low quantities), in which both the nature and concentration of the constituents in the final product varies often. It is an efficient and low cost method for the rapid identification of the optimal mixing device configuration, which contributes to the costs reduction and to the growing of the output.

scholarly journals Preparation and Characterization of High-Efficiency Magnetic Heavy Metal Capture Flocculants

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1732
Author(s):  
Yuanyuan Yu ◽  
Yongjun Sun ◽  
Jun Zhou ◽  
Aowen Chen ◽  
Kinjal J. Shah
Keyword(s):  
Heavy Metal ◽  
Reaction Time ◽  
High Efficiency ◽  
Removal Rate ◽  
Low Cost ◽  
Monomer Concentration ◽  
Synthesis Process ◽  
Response Surface Optimization ◽  
Metal Capture ◽  
Total Monomer Concentration

In this study, a high-efficiency magnetic heavy metal flocculant MF@AA was prepared based on carboxymethyl chitosan and magnetic Fe3O4. It was characterized by SEM, FTIR, XPS, XRD and VSM, and the Cu(II) removal rate was used as the evaluation basis for the preparation process. The effects of AMPS content, total monomer concentration, photoinitiator concentration and reaction time on the performance of MF@AA flocculation to remove Cu(II) were studied. The characterization results show that MF@AA has been successfully prepared and exhibits good magnetic induction characteristics. The synthesis results show that under the conditions of 10% AMPS content, 35% total monomer concentration, 0.04% photoinitiator concentration, and 1.5 h reaction time, the best yield of MF@AA is 77.69%. The best removal rate is 87.65%. In addition, the response surface optimization of the synthesis process of MF@AA was performed. The optimal synthesis ratio was finally determined as iron content 6.5%, CMFS: 29.5%, AM: 53.9%, AMPS: 10.1%. High-efficiency magnetic heavy metal flocculant MF@AA shows excellent flocculation performance in removing Cu(II). This research provides guidance and ideas for the development of efficient and low-cost flocculation technology to remove Cu(II) in wastewater.

scholarly journals Injection Molding and Near-Complete Densification of Monolithic and Al2O3 Fiber-Reinforced Ti2AlC MAX Phase Composites

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3632
Author(s):  
Sylvain Badie ◽  
Rimy Gabriel ◽  
Doris Sebold ◽  
Robert Vaßen ◽  
Olivier Guillon ◽  
...  
Keyword(s):  
Injection Molding ◽  
Graphite Powder ◽  
Max Phase ◽  
Powder Injection ◽  
Fiber Reinforced ◽  
Ceramic Fibers ◽  
Plasma Sintering ◽  
Molded Parts ◽  
Al2o3 Fiber ◽  
Induced Velocity

Near-net shape components composed of monolithic Ti2AlC and composites thereof, containing up to 20 vol.% Al2O3 fibers, were fabricated by powder injection molding. Fibers were homogeneously dispersed and preferentially oriented, due to flow constriction and shear-induced velocity gradients. After a two-stage debinding procedure, the injection-molded parts were sintered by pressureless sintering at 1250 °C and 1400 °C under argon, leading to relative densities of up to 70% and 92%, respectively. In order to achieve near-complete densification, field assisted sintering technology/spark plasma sintering in a graphite powder bed was used, yielding final relative densities of up to 98.6% and 97.2% for monolithic and composite parts, respectively. While the monolithic parts shrank isotropically, composite assemblies underwent anisotropic densification due to constrained sintering, on account of the ceramic fibers and their specific orientation. No significant increase, either in hardness or in toughness, upon the incorporation of Al2O3 fibers was observed. The 20 vol.% Al2O3 fiber-reinforced specimen accommodated deformation by producing neat and well-defined pyramidal indents at every load up to a 30 kgf (~294 N).

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