Vacuum Foaming of Aluminum Scrap

2012 ◽  
Vol 1481 ◽  
pp. 83-88
Author(s):  
J. A. Garabito ◽  
H. Granados ◽  
V. H. López ◽  
A. R. Kennedy ◽  
J. E. Bedolla
Keyword(s):  
Automotive Industry ◽  
Vacuum Chamber ◽  
Low Cost ◽  
Porous Structures ◽  
Aluminum Foams ◽  
Casting And Solidification ◽  
Different Temperatures ◽  
Different Levels ◽  
Al Foams

ABSTRACTIn this study, scrap from the automotive industry was used to produce aluminium foams under vacuum. Chips of an aluminium alloy LM26 were melted and 1wt. % of Mg was added for creating a viscous casting with uniform distribution of oxides. An ingot was obtained of this alloy after casting and solidification. Trials for foaming this alloy were performed by re-melting pieces under vacuum at different temperatures. A window in the vacuum chamber allowed observation of the foaming and collapse of the porous structures was observed during cooling. Characterization of the aluminum foams revealed different levels of expansion, porous structures and degrees of drainage. The best foams were obtained at 680 °C with a density of 0.78 g/cm3. This technique appears to be a feasible low cost route for producing Al foams based on scrap material.

scholarly journals Characterization of Eggshell: A Heterogeneous Catalyst in Transesterification of Sand Apple (Parinari polyandra) Seed Oil

2021 ◽  
Vol 25 (7) ◽  
pp. 1179-1185
Author(s):  
O.O. Oniya ◽  
A. Saleh ◽  
F.B. Akande ◽  
D.T. Adeyemi
Keyword(s):  
Heterogeneous Catalyst ◽  
Ethyl Ester ◽  
Reaction Temperature ◽  
Low Cost ◽  
Biodiesel Production ◽  
Increase With Increase ◽  
Solvent Extraction Method ◽  
Different Temperatures ◽  
Apple Fruits

The objective of this study was to characterize a low cost heterogeneous catalyst from the transesterification of sand apple (Parinari polyandra B.) biodiesel. Sand apple fruits were processed and oil was extracted using solvent extraction method. Raw eggshells were calcined at 800°C for 120 min in the muffle furnace. Surface properties of the raw and calcined eggshell were characterized using Fourier Transformed Infrared Radiation (FTIR) and X-Ray Fluorescence (XRF). Transesterification of the Sand Apple Oil (SASO) with ethanol in the presence of the calcined catalyst to produce ethyl ester and glycerol were optimized using Central Composite Design at different temperatures and time. Reactants for the transesterification process were the raw SASO and anhydrous ethanol. The study shows that raw eggshell was more stable with hydrogen bond form at 2,724 cm-1an while oil yield of 53.13 % was obtained from sand apple kernels. Ethyl ester yield of 90% was obtained from SASO. The results of transesterification shows the maximum biodiesel yield of 90% was obtained at reaction temperature of 65°C and time of 120 min, while the minimum yield of 70% was obtained at temperature of 55°C and time of 60 min; indicating that biodiesel increase with increase in time. Similarly, yield of ethyl ester of SASO also increased when the reaction temperature increased. The percentages of biodiesel yield obtained from SASO transesterification in this study showed that sand apple is promising oil for biodiesel production as compared with other vegetable oil crop obtained in previous studies

Fabrication and Characterization of a Poly (3-Hexylthiophene) Thin Film Micro-sensor for Hypergolic Vapor Detection

2006 ◽  
Vol 951 ◽  
Author(s):  
Huihua Shu ◽  
Jiehui Wan ◽  
John Shu ◽  
Hong Yang ◽  
Bryan A. Chin
Keyword(s):  
Thin Film ◽  
Thermal Stability ◽  
Low Cost ◽  
Vapor Detection ◽  
Different Temperatures ◽  
Micro Sensor ◽  
Low Levels ◽  
Manufacturing Techniques ◽  
Microelectronic Manufacturing

ABSTRACTA passive chemiresistor micro-sensor was investigated for the detection of hydrazine compounds. Hydrazine compounds are a highly toxic and carcinogenic species exhibiting toxic effects in humans at very low levels of exposure. Therefore, a sensor capable of detecting ppb levels of hydrazine compounds is required to insure the safety of personnel. The present study describes the fabrication, testing, and characterization of a low-cost, ultrasensitive Poly (3-Hexylthiophene) (P3HT) thin film-based micro-sensor for the detection of hydrazine compounds. Standard microelectronic manufacturing techniques were used to form a micro-sensor composed of a silicon substrate, interdigitated gold electrodes, and P3HT sensing film. Responses of the micro-sensor to hydrazine compounds at different temperatures and concentration levels are reported. When exposed to 25 ppm hydrazine in nitrogen, the sensor's resistance was measured to change from a few ohms to over 10 Megaohms. The thermal stability of the P3HT micro-sensor and the method to improve thermal stability are also explored. Thermally annealing the P3HT micro-sensor was found to improve thermal stability at high temperatures. Moreover, the sensor exhibits good specificity to hydrazine and does not respond to the presence of NO2 and/or N2O.

Characterization and Comparative Study of Pseudo-Elastic Cu-Zn-Al Foams Synthesized by Two Different Methods

2013 ◽  
Vol 738-739 ◽  
pp. 172-176 ◽  
Author(s):  
Brenda A. Weiss ◽  
Pierre Arneodo Larochette ◽  
Graciela Bertolino ◽  
Enrique M. Castrodeza ◽  
Alberto Baruj ◽  
...  
Keyword(s):  
Low Cost ◽  
Synthesis Method ◽  
Point Of View ◽  
Physico Chemical ◽  
Structural Applications ◽  
Preparation Techniques ◽  
Sio2 Spheres ◽  
Al Foams

Low cost Cu-Zn-Al foams present, in specific composition ranges, good pseudoelastic properties associated with interesting damping capacities, which establish these materials as attractive from the point of view of structural applications. These foams are manufactured by infiltration of small SiO2 spheres into the molten alloys. After alloy solidification the SiO2 spheres are removed by immersing the material in a solution of aqueous hydrofluoric acid. In this work, we have investigated the effect of two different foam preparation techniques: inductive and resistive melting. The paper details both the physico-chemical and mechanical characterization of the foams synthesized with the two different methods. The purpose of this study is to determine the quality of each synthesis method in order to identify the best alternative.

Synthesis and Characterization of Nanocrystalline ZnO Powders by a Direct Thermal Decomposition Route Using Zinc Nitrate Hexahydrate

2013 ◽  
Vol 770 ◽  
pp. 68-71 ◽  
Author(s):  
Supphadate Sujinnapram ◽  
Uraiphorn Termsuk ◽  
Atcharawan Charoentam ◽  
Sutthipoj Sutthana
Keyword(s):  
Thermal Decomposition ◽  
Crystallization Temperature ◽  
Zinc Nitrate ◽  
Zinc Nitrate Hexahydrate ◽  
Absorption Peak ◽  
Synthesis And Characterization ◽  
Nitrate Hexahydrate ◽  
Different Temperatures ◽  
Zno Powders

The nanocrystalline ZnO powders were synthesized by a direct thermal decomposition using zinc nitrate hexahydrate as starting materials. The precursor was characterized by TG-DTA to determine the thermal decomposition and crystallization temperature which was found to be at 325 oC. The precursors were calcined at different temperatures of 400, 500, and 600°C for 4 h. The structure of the prepared samples was studied by XRD, confirming the formation of wurtzite structure. The synthesized powders exhibited the UV absorption below 400 nm (3.10 eV) with a well defined absorption peak at around 285 nm (4.35 eV). The estimated direct bandgaps were obtained to be 3.19, 3.16, and 3.14 eV for the ZnO samples thermally decomposed at 400, 500, and 600°C, respectively.

scholarly journals Microstructure and Thermoelectric Properties of (Bi0.48Sb1.52)Te3 Thick Films Prepared with Tape Casting Method

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 140
Author(s):  
Lichen Liu ◽  
Ziping Cao ◽  
Min Chen ◽  
Jun Jiang
Keyword(s):  
Thermoelectric Properties ◽  
Low Cost ◽  
Thick Films ◽  
Tape Casting ◽  
Casting Process ◽  
Casting Method ◽  
Glass Substrates ◽  
Conductive Films ◽  
Casting Technology

This paper reports the fabrication and characterization of (Bi0.48Sb1.52)Te3 thick films using a tape casting process on glass substrates. A slurry of thermoelectric (Bi0.48Sb1.52)Te3 was developed and cured thick films were annealed in a vacuum chamber at 500–600 °C. The microstructure of these films was analyzed, and the Seebeck coefficient and electric conductivity were tested. It was found that the subsequent annealing process must be carefully designed to achieve good thermoelectric properties of these samples. Conductive films were obtained after annealing and led to acceptable thermoelectric performance. While the properties of these initial materials are not at the level of bulk materials, this work demonstrates that the low-cost tape casting technology is promising for fabricating thermoelectric modules for energy conversion.

The Growth and Characterization of Germanium-Carbon Alloy Thin Films

1992 ◽  
Vol 270 ◽  
Author(s):  
Haojie Yuan ◽  
R. Stanley Williams
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Vacuum Chamber ◽  
Optical Band Gap ◽  
High Vacuum ◽  
Optical Absorption Spectroscopy ◽  
Alloy Thin Film ◽  
New Materials ◽  
X Ray

ABSTRACTThin films of pure germanium-carbon alloys (GexC1−x with x ≈ 0.0, 0.2, 0.4, 0.5, 0.6, 0.8, 1.0) have been grown on Si(100) and A12O3 (0001) substrates by pulsed laser ablation in a high vacuum chamber. The films were analyzed by x-ray θ-2θ diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), conductivity measurements and optical absorption spectroscopy. The analyses of these new materials showed that films of all compositions were amorphous, free of contamination and uniform in composition. By changing the film composition, the optical band gap of these semiconducting films was varied from 0.00eV to 0.85eV for x = 0.0 to 1.0 respectively. According to the AES results, the carbon atoms in the Ge-C alloy thin film samples has a bonding configuration that is a mixture of sp2 and sp3 hybridizations.

scholarly journals Theoretical and Empirical Characterization of Water as a Factor: Examples and Related Issues with the World Trade Model

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 459
Author(s):  
Ignacio Cazcarro ◽  
Albert E. Steenge
Keyword(s):  
World Trade ◽  
Low Cost ◽  
Virtual Water ◽  
Considerable Change ◽  
Water Research ◽  
Trade Model ◽  
The World ◽  
Main Model ◽  
Selection Of

This article originates from the theoretical and empirical characterization of factors in the World Trade Model (WTM). It first illustrates the usefulness of this type of model for water research to address policy questions related to virtual water trade, water constraints and water scarcity. It also illustrates the importance of certain key decisions regarding the heterogeneity of water and its relation to the technologies being employed and the prices obtained. With regard to WTM, the global economic input–output model in which multiple technologies can produce a “homogeneous output”, it was recently shown that two different mechanisms should be distinguished by which multiple technologies can arise, i.e., from “technology-specific” or from “shared” factors, which implies a mechanism-specific set of prices, quantities and rents. We discuss and extend these characterizations, notably in relation to the real-world characterization of water as a factor (for which we use the terms technology specific, fully shared and “mixed”). We propose that the presence of these separate mechanisms results in the models being sensitive to relatively small variations in specific numerical values. To address this sensitivity, we suggest a specific role for specific (sub)models or key choices to counter unrealistic model outcomes. To support our proposal we present a selection of simulations for aggregated world regions, and show how key results concerning quantities, prices and rents can be subject to considerable change depending on the precise definitions of resource endowments and the technology-specificity of the factors. For instance, depending on the adopted water heterogeneity level, outcomes can vary from relatively low-cost solutions to higher cost ones and can even reach infeasibility. In the main model discussed here (WTM) factor prices are exogenous, which also contributes to the overall numerical sensitivity of the model. All this affects to a large extent our interpretation of the water challenges, which preferably need to be assessed in integrated frameworks, to account for the main socioeconomic variables, technologies and resources.

scholarly journals Simultaneous determination of various platycosides in Four Platycodon grandiflorum cultivars by UPLC-QTOF/MS

2019 ◽  
Vol 62 (1) ◽  
Author(s):  
Dae Young Lee ◽  
Bo-Ram Choi ◽  
Jae Won Lee ◽  
Yurry Um ◽  
Dahye Yoon ◽  
...  
Keyword(s):  
Principal Component ◽  
Ultra Performance Liquid Chromatography ◽  
Platycodon Grandiflorum ◽  
Pentacyclic Triterpenoid ◽  
Flight Mass Spectrometry ◽  
Platycodi Radix ◽  
Isomeric Pairs ◽  
Different Levels

Abstract In Platycodi Radix (root of Platycodon grandiflorum), there are a number of platycosides that consist of a pentacyclic triterpenoid aglycone and two sugar moieties. Due to the pharmacological activities of platycosides, it is critical to assess their contents in PR, and develop an effective method to profile various platycosides is required. In this study, an analytical method based on ultra performance liquid chromatography coupled with quadrupole time-of-flight/mass spectrometry (UPLC-QTOF/MS) with an in-house library was developed and applied to profile various platycosides from four different Platycodi Radix cultivars. As a result, platycosides, including six isomeric pairs, were successfully analyzed in the PRs. In the principal component analysis, several platycosides were represented as main variables to differentiate the four Platycodi Radix cultivars. Their different levels of platycosides were also represented by relative quantification. Finally, this study indicated the proposed method based on the UPLC-QTOF/MS can be an effective tool for identifying the detail characterization of various platycosides in the Platycodi Radix.

scholarly journals Spectral Decomposition of the Flow and Characterization of the Sound Signals through Stenoses with Different Levels of Severity

2021 ◽  
Vol 8 (3) ◽  
pp. 41
Author(s):  
Fardin Khalili ◽  
Peshala T. Gamage ◽  
Amirtahà Taebi ◽  
Mark E. Johnson ◽  
Randal B. Roberts ◽  
...  
Keyword(s):  
Pressure Fluctuations ◽  
High Energy ◽  
Sound Sources ◽  
Severity Level ◽  
Non Invasive ◽  
Flow Through ◽  
Severity Of The Disease ◽  
Proper Orthogonal ◽  
Different Levels

Treatments of atherosclerosis depend on the severity of the disease at the diagnosis time. Non-invasive diagnosis techniques, capable of detecting stenosis at early stages, are essential to reduce associated costs and mortality rates. We used computational fluid dynamics and acoustics analysis to extensively investigate the sound sources arising from high-turbulent fluctuating flow through stenosis. The frequency spectral analysis and proper orthogonal decomposition unveiled the frequency contents of the fluctuations for different severities and decomposed the flow into several frequency bandwidths. Results showed that high-intensity turbulent pressure fluctuations appeared inside the stenosis for severities above 70%, concentrated at plaque surface, and immediately in the post-stenotic region. Analysis of these fluctuations with the progression of the stenosis indicated that (a) there was a distinct break frequency for each severity level, ranging from 40 to 230 Hz, (b) acoustic spatial-frequency maps demonstrated the variation of the frequency content with respect to the distance from the stenosis, and (c) high-energy, high-frequency fluctuations existed inside the stenosis only for severe cases. This information can be essential for predicting the severity level of progressive stenosis, comprehending the nature of the sound sources, and determining the location of the stenosis with respect to the point of measurements.

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