| 1. |
- Askari, SJ, et al.
(författare)
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Synthesis and characterization of nano-crystalline CVD diamond film on pure titanium using Ar/CH 4/H 2 gas mixture
- 2007
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Ingår i: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 61:11-12, s. 2139-2142
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Tidskriftsartikel (refereegranskat)abstract
- Titanium and Ti alloys have poor tribological properties and deposition of a well adherent diamond coating is a promising way to solve this problem. But diamond film deposition on pure titanium and Ti alloys is always difficult due to the high diffusion coefficient of carbon in Ti, the large mismatch in their thermal expansion coefficients, the complex nature of the interlayer formed during diamond deposition, and the difficulty of achieving very high nucleation density. A nano-crystalline diamond (NCD) film can resolve Ti and Ti alloys weak tribological performance due to its smooth surface. A well-adhered NCD film was successfully deposited on pure Ti substrate by using a microwave plasma assisted chemical vapor deposition (MWPCVD) system in the environment of Ar, CH4 and H2 gases at a moderate temperature. Detailed experimental results on the preparation, characterization and successful deposition of the NCD film on pure Ti are discussed
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| 2. |
- Ma, Chunyan, et al.
(författare)
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Towards Negative Carbon Dioxide Emissions: Capture of Carbon in Biosyngas by Aqueous Pentaethylenehexamine
- 2019
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Ingår i: Innovative Solutions for Energy Transitions. - Stockholm : Scanditale AB.
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Konferensbidrag (refereegranskat)abstract
- In this work, aqueous pentaethylenehexamine (PEHA) was studied as a solvent for CO2 removal to produce purified bio-syngas from biomass gasification, but also as a first step towards negative carbon emissions applying carbon capture and storage (CCS) technologies. Capture of CO2 was tested both with synthetic gas (labscale) and real syngases from the pilot-scale gasifier fed with a wide range of forest-based biomasses. The results showed that the effects of the components other than CO2 and the impurities from the real syngas on the performance of PEHA for CO2 removal are negligible. Combined with previous research results from labtesting with pure CO2 absorption, the aqueous PEHA was shown to be a promising solvent for CO2 removal from syngas. PEHA was also tested as a biomass pre-treatment agent to improve gasification behavior, however, no significant improvement could be identified during the tests performed in this study.
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| 3. |
- Ma, Chunyan, et al.
(författare)
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Towards negative carbon emissions : Carbon capture in bio-syngas from gasification by aqueous pentaethylenehexamine
- 2020
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Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 279
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Tidskriftsartikel (refereegranskat)abstract
- In this work, an aqueous pentaethylenehexamine (PEHA) solution was studied for CO2 removal from bio-syngas for the first time. Firstly, pure CO2 absorption in aqueous PEHA solution under different conditions was conducted, and 20 wt% PEHA solution was identified as the best option. Secondly, the capture of CO2 was tested with synthetic syngas from a gas cylinder, and the species other than CO2 showed a negligible impact on CO2 removal. Finally, to evaluate the practical feasibility of using aqueous PEHA solution on the downstream CO2 capture, the pilot experiments of gasification with boreal forest-based biomasses were designed to provide real syngas with a realistic distribution in composition for further testing. The results showed that the operating conditions and the type of feedstocks affected the distribution in the bio-syngas composition. Among these feedstocks, at the optimal oxygen supply, using spruce needles generated the highest yields of CO and H2 and, meanwhile, gave rise to similar yields of other gases such as CO2, CH4, etc. The influence of the species other than CO2 for CO2 removal was negligible. Additionally, aqueous PEHA solution was tested as a biomass pretreatment agent, showing that no significant changes could be identified by the ultimate analysis (except for increased nitrogen content), but the yields of CO were affected negatively. On the other hand, when using the pretreated biomass by the aqueous PEHA solution, the NH3 concentration in bio-syngas reached to the highest (4000 parts per million), which slightly affected the CO2 absorption capacity and initial absorption rate of 20 wt% PEHA solution in a positive way.
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| 4. |
- Wang, Y.-D., et al.
(författare)
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Grain-to-grain stress interactions in an electrodeposited iron coating
- 2005
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 17:10, s. 1221-1226
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Tidskriftsartikel (refereegranskat)abstract
- The distribution of residual stresses, in an iron electrolytic coating with the thickness of 1 mm, was discussed. It was found that the coating minimizes the influence of crystallographic texture and stress gradients. Scanning electron microscopy observations indicate that some cracks are produced in the direct current deposited layer. The results show that the grain size in the electrolytic coating observed by transmission electron microscopy is around 20 nm with an aspect ratio of 5:1
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