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Binder evaporation during powder sheet Additive Manufacturing
Several Additive Manufacturing methods are well established and found access into regular production in
multiple sectors. For processing metals, typically wire or powder is used as feedstock. Wire processing is typically
used for comparably large structure building, while powder processes offer, in general, a more precise metal
application. For Powder Bed Fusion processes, very fine powder is used (typical 20 ”m to 65 ”m), while for
Directed Energy Deposition powders are in the range between 50 ”m and 160 ”m. Such fine powders can be a
health risk for humans (aspiration, skin integration). Avoiding contact with the powders in a production
environment can be a big effort or not avoidable. Therefore, an alternative process was developed that provides
the powder not as free powder particles but in form of powder sheets. For enabling the necessary bonding between
the particles, a binder is used. In order to understand the impact of the binder during laser processing of the powder
sheets, single pulse and line treatments were produced and recorded with high-speed imaging. Recordings show
the vaporization of the binder and the related ejections of powder particles. At lower energy input, the binder
evaporation led to less spattering, which indicates that a binder heating at low heating rates induces less pressure
on the powder particles.Mechanical Engineerin
Mitsui-7, heat-treated, and nitrogen-doped multi-walled carbon nanotubes elicit genotoxicity in human lung epithelial cells
Background: The unique physicochemical properties of multi-walled carbon nanotubes (MWCNT) have led to many industrial applications. Due to their low density and small size, MWCNT are easily aerosolized in the workplace making respiratory exposures likely in workers. The International Agency for Research on Cancer designated the pristine Mitsui-7 MWCNT (MWCNT-7) as a Group 2B carcinogen, but there was insufficient data to classify all other MWCNT. Previously, MWCNT exposed to high temperature (MWCNT-HT) or synthesized with nitrogen (MWCNT-ND) have been found to elicit attenuated toxicity; however, their genotoxic and carcinogenic potential are not known. Our aim was to measure the genotoxicity of MWCNT-7 compared to these two physicochemically-altered MWCNTs in human lung epithelial cells (BEAS-2B & SAEC). Results: Dose-dependent partitioning of individual nanotubes in the cell nuclei was observed for each MWCNT material and was greatest for MWCNT-7. Exposure to each MWCNT led to significantly increased mitotic aberrations with multi- and monopolar spindle morphologies and fragmented centrosomes. Quantitative analysis of the spindle pole demonstrated significantly increased centrosome fragmentation from 0.024â2.4 ÎŒg/mL of each MWCNT. Significant aneuploidy was measured in a dose-response from each MWCNT-7, HT, and ND; the highest dose of 24 ÎŒg/mL produced 67, 61, and 55%, respectively. Chromosome analysis demonstrated significantly increased centromere fragmentation and translocations from each MWCNT at each dose. Following 24 h of exposure to MWCNT-7, ND and/or HT in BEAS-2B a significant arrest in the G1/S phase in the cell cycle occurred, whereas the MWCNT-ND also induced a G2 arrest. Primary SAEC exposed for 24 h to each MWCNT elicited a significantly greater arrest in the G1 and G2 phases. However, SAEC arrested in the G1/S phase after 72 h of exposure. Lastly, a significant increase in clonal growth was observed one month after exposure to 0.024 ÎŒg/mL MWCNT-HT & ND. Conclusions: Although MWCNT-HT & ND cause a lower incidence of genotoxicity, all three MWCNTs cause the same type of mitotic and chromosomal disruptions. Chromosomal fragmentation and translocations have not been observed with other nanomaterials. Because in vitro genotoxicity is correlated with in vivo genotoxic response, these studies in primary human lung cells may predict the genotoxic potency in exposed human populations
In situ label-free imaging of hemicellulose in plant cell walls using stimulated Raman scattering microscopy
Applications of lignin in the agri-food industry
Of late, valorization of agri-food industrial by-products and their sustainable utilization is
gaining much contemplation world-over. Globally, 'Zero Waste Concept' is promoted with
main emphasis laid towards generation of minimal wastes and maximal utilization of plantbased
agri-food raw materials. One of the wastes/by-products in the agri-food industry are the
lignin, which occurs as lignocellulosic biomass. This biomass is deliberated to be an
environmental pollutant as they offer resistance to natural biodegradation. Safe disposal of this
biomass is often considered a major challenge, especially in low-income countries. Hence, the
application of modern technologies to effectively reduce these types of wastes and maximize
their potential use/applications is vital in the present day scenario. Nevertheless, in some of the
high-income countries, attempts have been made to efficiently utilize lignin as a source of fuel, as a raw material in the paper industry, as a filler material in biopolymer based packaging and
for producing bioethanol. However, as of today, agri-food industrial applications remains
significantly underexplored. Chemically, lignin is heterogeneous, bio-polymeric, polyphenolic
compound, which is present naturally in plants, providing mechanical strength and rigidity.
Reports are available wherein purified lignin is established to possess therapeutic values; and
are rich in antioxidant, anti-microbial, anti-carcinogenic, antidiabetic properties, etc.
This chapter is divided into four sub-categories focusing on various technological
aspects related to isolation and characterization of lignin; established uses of lignin; proved
bioactivities and therapeutic potentials of lignin, and finally on identifying the existing research
gaps followed by future recommendations for potential use from agri-food industrial wastes.Theme of this chapter is based on our ongoing project- Valortech,
which has received funding from the European Unionâs Horizon 2020 research and innovation
program under grant agreement No 810630
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