| 1. |
- Flores Ituarte, Iñigo, et al.
(författare)
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Additive Manufacturing of Polypropylene : A Screening Design of Experiment Using Laser-Based Powder Bed Fusion
- 2018
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Ingår i: Polymers. - : MDPI. - 2073-4360. ; 10:12
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Tidskriftsartikel (refereegranskat)abstract
- The use of commodity polymers such as polypropylene (PP) is key to open new market segments and applications for the additive manufacturing industry. Technologies such as powder-bed fusion (PBF) can process PP powder; however, much is still to learn concerning process parameters for reliable manufacturing. This study focusses in the process–property relationships of PP using laser-based PBF. The research presents an overview of the intrinsic and the extrinsic characteristic of a commercial PP powder as well as fabrication of tensile specimens with varying process parameters to characterize tensile, elongation at break, and porosity properties. The impact of key process parameters, such as power and scanning speed, are systematically modified in a controlled design of experiment. The results were compared to the existing body of knowledge; the outcome is to present a process window and optimal process parameters for industrial use of PP. The computer tomography data revealed a highly porous structure inside specimens ranging between 8.46% and 10.08%, with porosity concentrated in the interlayer planes in the build direction. The results of the design of experiment for this commercial material show a narrow window of 0.122 > Ev > 0.138 J/mm3 led to increased mechanical properties while maintaining geometrical stability.
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| 2. |
- Amruth, C., et al.
(författare)
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Inkjet printing of thermally activated delayed fluorescence (TADF) dendrimer for OLEDs applications
- 2019
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Ingår i: Organic electronics. - Amsterdam : Elsevier. - 1566-1199 .- 1878-5530. ; 74, s. 218-227
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Tidskriftsartikel (refereegranskat)abstract
- This study presents the inkjet printing of a novel OLED device with fully solution-processed organic layers that employ TADF material as an emitting layer. The ink was formulated using new TADF material, triazine core carbazole dendrimers with tert-butyl group at the periphery (tBuG2TAZ), dissolved in a mixture of two non-chlorinated solvents. The influence of the print resolution and the substrate temperature on morphology of the printed films was studied and optimized in ambient conditions. The optimized TADF dendrimer layer was then incorporated in the OLEDs as the emitting layer. The best-printed OLEDs exhibited a maximum current efficiency of 18 cd/A and maximum luminance of 6900 cd/m(2). Such values are comparable to the values obtained in spin coated devices made of the same TADF dendrimer. Further, the mobility of charge carriers extracted from transient electroluminescence measurements of printed OLEDs, when compared to reference OLEDs made by spin coating technique, showed similar values. Finally, we have demonstrated the possibility of patterning of emission the area of complex shapes merely by selectively printing the emission layer. These results demonstrate the potential application of the new dendrimer TADF emitters for the fabrication of efficient OLEDs by an inkjet printing technique.
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| 3. |
- Jansson, Anton, 1986-, et al.
(författare)
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Numerical analysis of compression strength in network structures based on trusses, and periodic surfaces aimed for additive manufacturing
- 2018
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Ingår i: Proceedings of the International Conference on Progress in Additive Manufacturing. - Singapore : Nanyang Technological University. ; , s. 328-333
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Konferensbidrag (refereegranskat)abstract
- In this paper, the compressive response for a number of truss- and surface-based networks with equal relative density was compared. The effect of errors in the structures were also investigated. The results show that surface networks are, in general, more efficient structures than truss-lattices in compression. The results also show that surface networks are significantly more resilient to fabrication errors than their truss-lattice counterparts.
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| 4. |
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| 5. |
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| 6. |
- Liem-Nguyen, Van, et al.
(författare)
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Removal mechanism of arsenic (V) by stainless steel slags obtained from scrap metal recycling
- 2020
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Ingår i: Journal of Environmental Chemical Engineering. - : Elsevier. - 2213-3437. ; 8:4
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Tidskriftsartikel (refereegranskat)abstract
- With this study, the removal mechanisms of arsenate by steel slag and its potential for treatment of contaminated water were elucidated. While original slag showed a poor fit to the Langmuir equation (R2 = 0.960), washed slag (the original slag is washed by low pH water solutions to remove readily soluble oxides) conformed better (R2 = 0.995). An initial pH of 2.0 give optimal adsorption, with a strong impact from the chemical speciation observed with highest efficiency for the fully protonated (OH)3AsO form. Adsorption capacity of the slag is 4.0 mg g−1, while together with precipitation the retention capacity reaches 13.7 mg g−1. However, removal by precipitation is a non-steady process due to re-dissolution of Ca3(AsO4)2(s). The washed slag shows a similar adsorption capacity to the original one but has not as strong alkaline properties. Batch experiment shows fast adsorption kinetics and column loading tests indicate an instant adsorption kinetics with 80 % As(V) removal for a 10 mg L−1 As(V) solution by 1.0 g of washed slag using a solution flowrate of 1 mL min−1. Common ions like sulfate, carbonate, chloride, iron(III), humic acid and fulvic acid do not significantly interfere with the removal efficiency. In combination with limited hazardous metals leaching, the slag is thus appropriate for use as a filter material for treatment of contaminated water and it has been successfully applied as filter material for treatment of arsenate spiked natural water sample with average removal efficiency of 84 % (solid to liquid ratio of 200).
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| 7. |
- Löthgren, Carl-Johan, et al.
(författare)
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Mercury speciation in flue gases after an oxidative acid wet scrubber
- 2007
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Ingår i: Chemical Engineering & Technology. - : Wiley. - 0930-7516 .- 1521-4125. ; 30:1, s. 131-138
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Tidskriftsartikel (refereegranskat)abstract
- Flue gases from a hazardous waste incinerator have been sampled in three campaigns, before and after, an oxidative acid wet scrubber working with the MercOx-process. A continuous emission monitor for mercury speciation was used before the scrubber in the first campaign. In all campaigns, impingers with KCl and KMnO4 were used. A solid adsorption method was used in the last campaign. The mercury leaving the scrubber is oxidized at > 90 % efficiency (independent of the inlet speciation). A substantial decrease in the redox potential of the scrubber liquid caused an increased fraction of elemental gaseous mercury to be present in the clean gas. The measurements also show that the scrubber has the ability to readily absorb mercury peaks. During one extreme peak of 3,600 μg/m3 (dry gas) in the raw gas, the removal efficiency was above 99.9 %.
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| 8. |
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| 9. |
- Zhang, Ye, et al.
(författare)
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A regularization method for the reconstruction of adsorption isotherms in liquid chromatography
- 2016
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Ingår i: Inverse Problems. - : IOP PUBLISHING LTD. - 0266-5611 .- 1361-6420. ; 32:10
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Tidskriftsartikel (refereegranskat)abstract
- Determining competitive adsorption isotherms is an open problem in liquid chromatography. Since traditional experimental trial-and-error approaches are too complex and expensive, a modern technique of obtaining adsorption isotherms is to solve the inverse problem so that the simulated batch separation coincides with actual experimental results. This is a typical ill-posed problem. Moreover, in almost all cases the observed concentration at the outlet is the total response of all components, which makes the problem more difficult. In this work, we tackle the ill-posedness with a new regularization method, which is based on the fact that the adsorption isotherms do not depend on the injection profile. The proposed method transfers the original problem to an optimization problem with a time-dependent convection-diffusion equation constraint. Iterative algorithms for solving constraint optimization problems for both the equilibrium-dispersive and the transport-dispersive models are developed. The mass transfer resistance is also estimated by the proposed inverse method. A regularization parameter selection method and the convergence property of the proposed algorithm are discussed. Finally, numerical tests for both synthetic problems and real-world problems are given to show the efficiency and feasibility of the proposed regularization method.
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| 10. |
- Zhang, Ye, 1984-, et al.
(författare)
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An adaptive regularization algorithm for recovering the rate constant distribution from biosensor data
- 2018
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Ingår i: Inverse Problems in Science and Engineering. - Oxon, UK : Taylor & Francis. - 1741-5977 .- 1741-5985. ; 26:10, s. 1464-1489
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Tidskriftsartikel (refereegranskat)abstract
- We present here the theoretical results and numerical analysis of a regularization method for the inverse problem of determining the rate constant distribution from biosensor data. The rate constant distribution method is a modern technique to study binding equilibrium and kinetics for chemical reactions. Finding a rate constant distribution from biosensor data can be described as a multidimensional Fredholm integral equation of the first kind, which is a typical ill-posed problem in the sense of J. Hadamard. By combining regularization theory and the goal-oriented adaptive discretization technique, we develop an Adaptive Interaction Distribution Algorithm (AIDA) for the reconstruction of rate constant distributions. The mesh refinement criteria are proposed based on the a posteriori error estimation of the finite element approximation. The stability of the obtained approximate solution with respect to data noise is proven. Finally, numerical tests for both synthetic and real data are given to show the robustness of the AIDA.
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