Investigation of the Effect of Homogenization Practice of 6063 Alloy Billets on Beta to Alpha Transformation and of the Effect of Cooling Rate on Precipitation Kinetics

2018 ◽  
Vol 941 ◽  
pp. 884-889 ◽  
Author(s):  
Marianna Katsivarda ◽  
Athanasios Vazdirvanidis ◽  
George Pantazopoulos ◽  
Nikos Kolioubas ◽  
Sofia Papadopoulou ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Cooling Rate ◽  
Low Cost ◽  
Scanning Calorimetry ◽  
Joint Research ◽  
Intermetallic Particles ◽  
Joint Research Project ◽  
Mean Diameter ◽  
Size And Morphology ◽  
Temperature Time

A joint research project was accomplished with the aim to determine the effect of homogenization conditions (temperature, time, cooling rate) on the microstructure and hardness of 6063 alloy billets. Homogenization is crucial for the ability to extrude the piece in low cost, but mainly without defects. Thus, it is of importance to determine the most suitable homogenization conditions (temperature, time, cooling rate) and its effect on both microstructure and hardness of 6063 alloy billets. Furthermore, the size and morphology of the AlFeMnSi intermetallic particles (mean diameter, aspect ratio) and the precipitation behavior of Mg2Si constituents are examined in detail via optical (OM) and scanning electron microscopy (SEM). The resulting mean diameter and aspect ratio data generated by such measurements using OM and image analysis of the intermetallics, that are relevant to the extent of beta-to-alpha transformation, are statistically processed with “ANOVA”. Differential Scanning Calorimetry (DSC) tests are used to determine the coherency level of the particles that were precipitated during the different cooling rates and to reveal the potential for resolutioning the precipitates during billet preheating. Samples received from the plant are compared to laboratory samples in order to facilitate the process of optimization the thermal treatment and improve extrudability.

scholarly journals T-history analysis of aspect ratio effect on subcooling and solidification behaviour of phase change material in vertical glass tubes

2020 ◽  
pp. 326-326
Author(s):  
Rudra Murthy ◽  
Veershetty Gumtapure
Keyword(s):  
Aspect Ratio ◽  
Phase Change ◽  
Cooling Rate ◽  
Phase Change Material ◽  
Glass Tube ◽  
Mean Value ◽  
Scanning Calorimetry ◽  
Constant Length ◽  
Aspect Ratios ◽  
Change Material

The study deals with the effect of the tube aspect ratio on subcooling and the solidification behavior of phase change material (PCM) using the T-history method (THM) and is compared with the differential scanning calorimetry (DSC) analysis. Three tubes of different aspect ratios (l/d) and a constant length of 178 mm are chosen for this study. Infrared (I.R.) contour depicts that the inner surface of the glass tube and PCM initiate heterogeneous nucleation. The DSC heat flow graph indicates a higher degree of subcooling (DOS) than THM. The study of aspect ratio with and without insulation shows that the mean value of DOS is less in the insulated tube than non-insulated tube due to reduced cooling rate. The effect of the high aspect ratio is to increase the DOS due to increased cooling rate and, however, decrease the sensible heat discharge time to reach the plateau (tplt).

scholarly journals Analysis of Thermal Degradation in the Annealing Process of Colored Parts Built by Extrusion-Based 3D Printing

2020 ◽  
Vol 5 (3) ◽  
pp. 124-133
Author(s):  
Kleber Leonardo Castro Vera ◽  
Leonardo Santana ◽  
Jorge Lino Alves
Keyword(s):  
Low Cost ◽  
Annealing Process ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Technical Data ◽  
Practical Applications ◽  
3D Printed ◽  
Color Degradation ◽  
Temperature Time ◽  
Design Experiments

With the ever-increasing request of light materials, poly lactic (acid) PLA, have got much in consideration. Low-cost PLA materials have risen its use. Those possess some benefits but nevertheless insufficient mechanical strength. The printed PLA objects have a stumbling block for practical applications. Thus, annealing is an interested alternative to make 3D printed objects strong. This thermal treatment can significantly develop investigational studies and offer technical data. Hence the purpose of this paper is study and discuss how to increase the flexural strength through annealing process. Geometry distortions and color degradation will be analyzed. Differential Scanning Calorimetry, Taguchi Method (TM) and variance (ANOVA) were applied as part of the design experiments and analysis. Twenty-seven printed specimens were tested and factors as temperature, time and color were selected.

Characterization of a Polymeric Membrane for the Separation of Hydrogen in a Mixture with CO2

2016 ◽  
Vol 9 (1) ◽  
pp. 126-136 ◽  
Author(s):  
Dionisio H. Malagón-Romero ◽  
Alexander Ladino ◽  
Nataly Ortiz ◽  
Liliana P. Green
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Production ◽  
Test Performance ◽  
Low Cost ◽  
Time Lag ◽  
Polymeric Membrane ◽  
Biological Processes ◽  
Scanning Calorimetry ◽  
Environmentally Sustainable ◽  
Production Of Hydrogen

Hydrogen is expected to play an important role as a clean, reliable and renewable energy source. A key challenge is the production of hydrogen in an economically and environmentally sustainable way on an industrial scale. One promising method of hydrogen production is via biological processes using agricultural resources, where the hydrogen is found to be mixed with other gases, such as carbon dioxide. Thus, to separate hydrogen from the mixture, it is challenging to implement and evaluate a simple, low cost, reliable and efficient separation process. So, the aim of this work was to develop a polymeric membrane for hydrogen separation. The developed membranes were made of polysulfone via phase inversion by a controlled evaporation method with 5 wt % and 10 wt % of polysulfone resulting in thicknesses of 132 and 239 micrometers, respectively. Membrane characterization was performed using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), atomic force microscopy (AFM), and ASTM D882 tensile test. Performance was characterized using a 23 factorial experiment using the time lag method, comparing the results with those from gas chromatography (GC). As a result, developed membranes exhibited dense microstructures, low values of RMS roughness, and glass transition temperatures of approximately 191.75 °C and 190.43 °C for the 5 wt % and 10 wt % membranes, respectively. Performance results for the given membranes showed a hydrogen selectivity of 8.20 for an evaluated gas mixture 54% hydrogen and 46% carbon dioxide. According to selectivity achieved, H2 separation from carbon dioxide is feasible with possibilities of scalability. These results are important for consolidating hydrogen production from biological processes.

Non-isothermal crystallization behavior of spinel crystals in FeO-SiO2-TiO2-V2O3-Cr2O3 slag

2018 ◽  
Vol 116 (1) ◽  
pp. 110
Author(s):  
Lixiong Shao ◽  
Jiang Diao ◽  
Wang Zhou ◽  
Tao Zhang ◽  
Bing Xie
Keyword(s):  
Cooling Rate ◽  
Crystallization Behavior ◽  
Crystal Size ◽  
Growth Mechanisms ◽  
Vanadium Slag ◽  
Growth Behaviour ◽  
Temperature Range ◽  
Chromium Spinel ◽  
Mean Diameter ◽  
The Mean

The growth behaviour of spinel crystals in vanadium slag with high Cr2O3 content was investigated and clarified by statistical analyses based on the Crystal Size Distribution (CSD) theory. The results indicate that low cooling rate and Cr2O3 content benefit the growth of spinel crystals. The chromium spinel crystals firstly precipitated and then acted as the heterogeneous nuclei of vanadium and titanium spinel crystals. The growth mechanisms of the spinel crystals at the cooling rate of 5 K/min consist two regimes: firstly, nucleation control in the temperature range of 1873 to 1773 K, in which the shapes of CSD curves are asymptotic; secondly, surface and supply control within the temperature range of 1773 to 1473 K, in which the shapes of CSD curves are lognormal. The mean diameter of spinel crystals increases from 3.97 to 52.21 µm with the decrease of temperature from 1873 to 1473 K.

scholarly journals Calorimetric analysis of ice onset temperature during cryoablation: a model approach to identify early predictors of effective applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elena Campagnoli ◽  
Andrea Ballatore ◽  
Valter Giaretto ◽  
Matteo Anselmino
Keyword(s):  
Cooling Rate ◽  
Latent Heat ◽  
Bovine Liver ◽  
Onset Temperature ◽  
Ice Formation ◽  
Scanning Calorimetry ◽  
Calorimetric Analysis ◽  
Early Predictors ◽  
Latent Heat Capacity ◽  
Model Approach

AbstractAim of the present study is to analyze thermal events occurring during cryoablation. Different bovine liver samples underwent freezing cycles at different cooling rate (from 0.0075 to 25 K/min). Ice onset temperature and specific latent heat capacity of the ice formation process were measured according to differential scanning calorimetry signals. A computational model of the thermal events occurring during cryoablation was compiled using Neumann’s analytical solution. Latent heat (#1 = 139.8 ± 7.4 J/g, #2 = 147.8 ± 7.9 J/g, #3 = 159.0 ± 4.1 J/g) of all liver samples was independent of the ice onset temperature, but linearly dependent on the water content. Ice onset temperature was proportional to the logarithm of the cooling rate in the range 5 ÷ 25 K/min (#3a = − 12.2 °C, #3b = − 16.2 °C, #3c = − 6.6 °C at 5K/min; #3a = − 16.5 °C, #3b = − 19.3 °C, #3c = − 11.6 °C at 25 K/min). Ice onset temperature was associated with both the way in which the heat involved into the phase transition was delivered and with the thermal gradient inside the tissue. Ice onset temperature should be evaluated in the early phase of the ablation to tailor cryoenergy delivery. In order to obtain low ice trigger temperatures and consequent low ablation temperatures a high cooling rate is necessary.

scholarly journals AFX Zeolite for Use as a Support of NH3-SCR Catalyst Mining through AICE Joint Research Project of Industries–Academia–Academia

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 163
Author(s):  
Masaru Ogura ◽  
Yumiko Shimada ◽  
Takeshi Ohnishi ◽  
Naoto Nakazawa ◽  
Yoshihiro Kubota ◽  
...  
Keyword(s):  
High Performance ◽  
Ionic Species ◽  
Research Project ◽  
Joint Research ◽  
Structure Directing Agent ◽  
Scr Catalyst ◽  
Organic Structure ◽  
Nh3 Scr ◽  
Joint Research Project ◽  
The One

This paper introduces a joint industries–academia–academia research project started by researchers in several automobile companies and universities working on a single theme. Our first target was to find a zeolite for NH3-SCR, that is, zeolite mining. Zeolite AFX, having the same topology of SSZ-16, was found to be the one of the zeolites. SSZ-16 can be synthesized by using an organic structure-directing agent such as 1,1′-tetramethylenebis(1-azonia-4-azabicyclo[2.2.2]octane; Dab-4, resulting in the formation of Al-rich SSZ-16 with Si/Al below five. We found that AFX crystallized by use of N,N,N′,N′-tetraethylbicyclo[2.2.2]oct-7-ene-2,3:5,6-dipyrrolidinium ion, called TEBOP in this study, had the same analog as SSZ-16 having Si/Al around six and a smaller particle size than SSZ-16. The AFX demonstrated a high performance for NH3-SCR as the zeolitic support to load a large number of divalent Cu ionic species with high hydrothermal stability.

The effect of cooling rate on crystallization behavior and tensile properties of CF/PEEK composites

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Guangming Dai ◽  
Lihua Zhan ◽  
Chenglong Guan ◽  
Minghui Huang
Keyword(s):  
Cooling Rate ◽  
Crystallization Temperature ◽  
Crystallization Behavior ◽  
Crystalline Polymer ◽  
Scanning Calorimetry ◽  
Nonisothermal Crystallization ◽  
Cooling Rates ◽  
Control Range ◽  
Temperature Range ◽  
Transverse Tensile

Abstract In this study, the differential scanning calorimetry (DSC) tests were performed to measure the nonisothermal crystallization behavior of carbon fiber reinforced polyether ether ketone (CF/PEEK) composites under different cooling rates. The characteristic parameters of crystallization were obtained, and the nonisothermal crystallization model was established. The crystallization temperature range of the material at different cooling rates was predicted by the model. The unidirectional laminates were fabricated at different cooling rates in the crystallization temperature range. The results showed that the crystallization temperature range shifted to a lower temperature with the increase of cooling rate, the established nonisothermal crystallization model was consistent with the DSC test results. It is feasible to shorten the cooling control range from the whole process to the crystallization range. The crystallinity and transverse tensile strength declined significantly with the increase of the cooling rate in the crystallization temperature range. The research results provided theoretical support for the selection of cooling conditions and temperature control range, which could be applied to the thermoforming process of semi-crystalline polymer matrixed composites to improve the manufacturing efficiency.

scholarly journals What sparks academic engagement with society? A comparison of incentives appealing to motives

2021 ◽  
pp. 095042222199406
Author(s):  
Eva Sormani ◽  
Thomas Baaken ◽  
Peter van der Sijde
Keyword(s):  
Higher Education ◽  
Academic Engagement ◽  
Career Advancement ◽  
Self Determination Theory ◽  
Self Determination ◽  
Third Mission ◽  
Research Support ◽  
Joint Research ◽  
Subject Design ◽  
Joint Research Project

The pressure on higher education institutions (HEIs) to realize third mission activities continues to grow, intensifying the search for incentives to motivate academics to engage with stakeholders outside their HEI. Previous studies have found limitations in intrinsically motivating academic engagement; therefore, this study investigates the extrinsic regulation of motivations via incentives. The authors identified a broad range of incentives for third mission activities, belonging to four motivation categories: pecuniary incentives, career advancement, appreciation and research support. Drawing on self-determination theory, incentives (nudges and rewards) are empirically compared in a between-subject design with a sample of 324 academics from the business and economics disciplines. The analysis showed that nudges affect business and economics academics’ intention to engage with society in a joint research project. Furthermore, these academics responded well to incentives concerned with the research support motivation category. The findings contribute to the literature by highlighting the relevance of marginal incentives—nudges—in implementing appropriate incentives in HEIs.

Corporate Finance in Germany and France. A Joint Research Project of the Deutsche Bundesbank and the Banque de France

1999 ◽  
Author(s):  
Hans Friderichs ◽  
Dieter Gerdesmeier ◽  
Elisabeth M. Kremp ◽  
Bernard Paranque ◽  
Annie Sauve ◽  
...  
Keyword(s):  
Corporate Finance ◽  
Research Project ◽  
Joint Research ◽  
Joint Research Project ◽  
Deutsche Bundesbank

Preferential dissolution along misoriented boundaries in heterogenite

2000 ◽  
Vol 620 ◽  
Author(s):  
R. Lee Penn ◽  
Alan T. Stone ◽  
David R. Veblen
Keyword(s):  
Electron Microscopy ◽  
Aspect Ratio ◽  
Reductive Dissolution ◽  
Morphology Evolution ◽  
Crystal Chemical ◽  
Transmission Electron ◽  
Micron Size ◽  
Primary Particles ◽  
Size And Morphology ◽  
Preferential Dissolution

ABSTRACTHigh-Resolution Transmission Electron Microscopy (HRTEM) results show a strong crystal-chemical and defect dependence on the mode of dissolution of synthetic heterogenite (CoOOH) particles. As-synthesized heterogenite particles are micron-size plates (aspect ratio ∼ 1/30) constructed of crystallographically oriented ∼ 3-nm primary particles or are single ∼ 21-nm unattached heterogenite platelets (aspect ratio ∼1/7). Reductive dissolution, using hydroquinone, was examined in order to evaluate morphology evolution as a function of reductant concentration. Two end-member modes of dissolution were observed: 1) non-specific dissolution of macroparticles and 2) preferential dissolution along misoriented boundaries. In the case of non-specific dissolution, average macrocrystal size and morphology are not altered as building block crystals are consumed. The result is web-like particles with similar breadth and shape as undissolved particles. Preferential dissolution involves the formation of channels or holes along boundaries of angular misorientation. Such boundaries involve only a few degrees of tilt, but dissolution occurs almost exclusively at such sites. Energy-Filtered TEM thickness maps show that the thickness of surrounding material is not significantly different from that of undissolved particles. Finally, natural heterogenite from Goodsprings, Nevada, shows morphology and microstructure similar to those of this synthetic heterogenite.

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