thermally processed
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2022 ◽  
Vol 58 (4) ◽  
pp. 250-260
Dragos Alexandrescu ◽  
Iulian Antoniac ◽  
Cristian Olteanu ◽  
Lucretia Anghel ◽  
Nicolae Sarbu ◽  

In the medical field the additive manufacturing process by fused deposition modeling has gained a great importance given the ability to create complex, organic geometries, in a short time period and the possibility of high customization. By fused deposition process the part is created layer by layer and the resulting part is characterized by high anisotropy, dictated mostly by printing parameters. To alleviate the anisotropy and to study the mechanical behavior of the 3D printed parts thermal processing is used. The materials used as filament is a poly (lactic acid) with copper particles embedded for antibacterial purposes. Samples were 3D printed using a commercial printer, thermally processed and tested in compression. On the failed specimens fracture investigations were performed to understand mechanical behavior during compression. The mechanical characteristics showed improvement and the anisotropy decreased as the processing temperature increased, but the samples became brittle. The mechanical behavior changed drastically on the thermally processed samples because of structural changes: a discontinuity between exterior layers and infill layers was created post layer fusion, the first region being the one stressed and failed first during tests.

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1963
Guochao Wang ◽  
Yafei Li ◽  
Weijian Chen ◽  
Jianguo Yang ◽  
Jie Zhang ◽  

Ti2AlC is a typical MAX (M: early transition metal, A: main group element, and X: carbon and/or nitrogen) phase with ceramic and metallic properties due to its unique nano-layered structure. In order to investigate the interaction behavior between Ag and Ti2AlC, a sessile drop experiment was conducted at 1080 °C for 5 min. The atomic rearrangement occurred at the Ag–Ti2AlC interface was revealed using high-angle annular dark-field scanning transmission electron microscopy coupled with high-resolution transmission electron microscopy analysis. The results show that Ag nanoclusters generally appeared in most of the Ag–Ti2AlC interaction regions thermally processed at 1080 °C. In addition, Ag can also substitute for Al and Ti atoms in the Ti2AlC, promoting local structural decomposition of the Ti2AlC and producing 4H–Ag with a hexagonal close-packed (hcp) structure. Additionally, Al atoms released from the Ti2AlC lattices can dissolve locally into the liquid Ag, particularly at the grain boundaries. When the loss concentration of Al exceeded the critical level, the Ti2AlC started to decompose and the residual Ti6C octahedrons and Al atoms recombined, giving rise to the production of anti-perovskite Ti3AlC with a cubic structure. Lastly, the discrepancy in substitution behavior of Ag in the Ti2AlC was compared when thermally processed at different temperatures (1030 °C and 1080 °C). This work contributes to the understanding of the intrinsic stability of Ti2AlC MAX ceramics under high-temperature treatment.

2021 ◽  
Vol 922 (2) ◽  
pp. 256
Giulia Perotti ◽  
Henning O. Sørensen ◽  
Henning Haack ◽  
Anja C. Andersen ◽  
Dario Ferreira Sanchez ◽  

Abstract Protoplanetary disks are dust- and gas-rich structures surrounding protostars. Depending on the distance from the protostar, this dust is thermally processed to different degrees and accreted to form bodies of varying chemical compositions. The primordial accretion processes occurring in the early protoplanetary disk such as chondrule formation and metal segregation are not well understood. One way to constrain them is to study the morphology and composition of forsteritic grains from the matrix of carbonaceous chondrites. Here, we present high-resolution ptychographic X-ray nanotomography and multimodal chemical microtomography (X-ray diffraction and X-ray fluorescence) to reveal the early history of forsteritic grains extracted from the matrix of the Murchison CM2.5 chondrite. The 3D electron density maps revealed, at unprecedented resolution (64 nm), spherical inclusions containing Fe–Ni, very little silica-rich glass and void caps (i.e., volumes where the electron density is consistent with conditions close to vacuum) trapped in forsterite. The presence of the voids along with the overall composition, petrological textures, and shrinkage calculations is consistent with the grains experiencing one or more heating events with peak temperatures close to the melting point of forsterite (∼2100 K), and subsequently cooled and contracted, in agreement with chondrule-forming conditions.

Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2423
Bin Wang ◽  
Shenghui Jiang ◽  
Yanbo Wang ◽  
Jihua Xu ◽  
Meng Xu ◽  

Furan is a volatile and carcinogenic heterocyclic chemical compound that occurs in a wide range of thermally processed food. It can be induced during food-preparing processes by high temperatures and UV-C light. In the present study, the degradation of furan content in ground coffee, Maillard model system, and not-from-concentrate (NFC) apple juice by red-fleshed apple anthocyanin extract (RAAE) was studied. The results demonstrated that RAAEs had different degrees of degradation of furan content in coffee powder, and the RAAE from ‘XJ3’ had the most significant effect, with a reduction rate of up to 20%. Moreover, by adding RAAE to the Maillard model system, we found the amounts of furan were significantly reduced. At the same time, RAAE from ‘XJ3’ could observably reduce the content of furan in pasteurized NFC juice, with ‘Fuli’ NFC juice furan content decreasing the most, which was 68%. Taken together, our study demonstrated that the use of RAAE could be a feasible way to reduce furan content in ground coffee, Maillard model system, and NFC apple juice.

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6479
Jacek Łyczko ◽  
Jacek A. Koziel ◽  
Chumki Banik ◽  
Andrzej Białowiec

One solution for sewage sludge (SS) management is thermochemical treatment due to torrefaction and pyrolysis with biochar production. SS biochar may contain toxic volatile organic compounds (VOCs) and polyaromatic hydrocarbons (PAHs). This study aimed to determine the process temperature's influence on the qualitative PAHs emission from SS-biochar and the transformation of PAHs contained in SS. SS was torrefied/pyrolyzed under temperatures 200–600°C with 1 h residence time. The headspace solid-phase microextraction (SPME) combined with gas chromatography and mass spectrometry (HS-SPME-GC-MS) analytical procedure of VOCs and PAHs emission was applied. The highest abundance of numerous VOCs was found for torrefaction ranges of temperature. The increase of temperatures to the pyrolytic range decreased the presence of VOCs and PAHs in biochar. The most common VOCs emitted from thermally processed SS were acetone, 2-methylfuran, 2-butanone, 3-metylbutanal, benzene, decalin, and acetic acid. The naphthalene present in SS converted to decalin (and other decalin derivatives), which may lead to SS biochar being considered hazardous material.

2021 ◽  
pp. 131465
Yu-Ting Zhuang ◽  
Liuyimai Ma ◽  
Hao Huang ◽  
Lu Han ◽  
Li Wang ◽  

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