| 1. |
- Hrastinski, Stefan, 1980-, et al.
(författare)
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Critical Imaginaries and Reflections on Artificial Intelligence and Robots in Postdigital K-12 Education
- 2019
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Ingår i: Postdigital Science and Education. - : Springer Science and Business Media LLC. - 2524-485X .- 2524-4868 .- 2662-5326. ; 1:2, s. 427-445
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Tidskriftsartikel (refereegranskat)abstract
- It is commonly suggested that emerging technologies will revolutionize education. In this paper, two such emerging technologies, artificial intelligence (AI) and educational robots (ER), are in focus. The aim of the paper is to explore how teachers, researchers and pedagogical developers critically imagine and reflect upon how AI and robots could be used in education. The empirical data were collected from discussion groups that were part of a symposium. For both AI and ERs, the need for more knowledge about these technologies, how they could preferably be used, and how the emergence of these technologies might affect the role of the teacher and the relationship between teachers and students, were outlined. Many participants saw more potential to use AI for individualization as compared with ERs. However, there were also more concerns, such as ethical issues and economic interests, when discussing AI. While the researchers/developers to a greater extent imagined ideal future technology-rich educational practices, the practitioners were more focused on imaginaries grounded in current practice.
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| 2. |
- Gustafsson, Anna, 1980, et al.
(författare)
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Evaluation of High-Temperature Chlorination as a Process for Separation of Copper, Indium and Gallium from CIGS Solar Cell Waste Materials
- 2015
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Ingår i: Separation Science and Technology. - : Informa UK Limited. - 1520-5754 .- 0149-6395. ; 50:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- CIGS (copper indium gallium diselenide) is a semiconductor used in high efficiency thin film solar cells. Several of these elements are considered to be fairly rare and thus expensive. In order to ensure future supply of the metals, an efficient recycling process for CIGS is needed. We have previously published a process for the separation of high purity selenium from CIGS solar cell waste materials. In the present paper we evaluate the possibility of using high-temperature chlorination to separate copper, indium, and gallium from the residue obtained in the selenium separation process. The chlorination agents used were chlorine gas, hydrogen chloride gas, and ammonium chloride. The goal was to use different temperatures to separate the metal chlorides formed. Ammonium chloride was shown to be the most promising chlorination agent for future process optimization.
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| 3. |
- Gustafsson, Anna, 1980, et al.
(författare)
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Investigation of an electrochemical method for separation of copper, indium, and gallium from pretreated cigs solar cell waste materials
- 2015
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Ingår i: The Scientific World Journal. - : Hindawi Limited. - 1537-744X .- 2356-6140. ; 2015
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Tidskriftsartikel (refereegranskat)abstract
- Recycling of the semiconductor material copper indium gallium diselenide (CIGS) is important to ensure a future supply of indium and gallium, which are relatively rare and therefore expensive elements. As a continuation of our previous work, where we recycled high purity selenium from CIGS waste materials, we now show that copper and indium can be recycled by electrodeposition from hydrochloric acid solutions of dissolved selenium-depleted material. Suitable potentials for the reduction of copper and indium were determined to be -0.5 V and -0.9 V (versus the Ag/AgCl reference electrode), respectively, using cyclic voltammetry. Electrodeposition of first copper and then indium from a solution containing the dissolved residue from the selenium separation and ammonium chloride in 1 M HCl gave a copper yield of 100.1 ± 0.5% and an indium yield of 98.1 ± 2.5%. The separated copper and indium fractions contained no significant contamination of the other elements. Gallium remained in solution together with a small amount of indium after the separation of copper and indium and has to be recovered by an alternative method since electrowinning from the chloride-rich acid solution was not effective.
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| 4. |
- Gustafsson, Anna, 1980, et al.
(författare)
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Recycling of CIGS Solar Cell Waste Materials: Separation of Copper, Indium, and Gallium by High-Temperature Chlorination Reaction with Ammonium Chloride
- 2015
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Ingår i: Separation Science and Technology. - : Informa UK Limited. - 1520-5754 .- 0149-6395. ; 50:15, s. 2415-2425
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Tidskriftsartikel (refereegranskat)abstract
- Recycling of copper indium gallium diselenide (CIGS) solar cell materials is important to ensure future supply of indium and gallium. Our previous work includes recycling of selenium from CIGS materials and a scoping study on high-temperature chlorination for the separation of the remaining elements using different chlorination agents. In the present work we further develop high-temperature chlorination separation using ammonium chloride. The study showed that 97 wt% of the gallium and 93 wt% of the indium could be recovered at 260 and 340°C, respectively. The process resulted in good separation between gallium and copper while the indium content in the gallium and copper fractions were above the goal of 1 wt%.
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| 5. |
- Karlsson, Toni, 1984, et al.
(författare)
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Investigations into Recycling Zinc from Used Metal Oxide Varistors via pH Selective Leaching: Characterization, Leaching, and Residue Analysis
- 2015
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Ingår i: Scientific World Journal. - : Hindawi Limited. - 2356-6140 .- 1537-744X. ; 2015
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Tidskriftsartikel (refereegranskat)abstract
- Metal oxide varistors (MOVs) are a type of resistor with significantly nonlinear current-voltage characteristics commonly used in power lines to protect against overvoltages. If a proper recycling plan is developed MOVs can be an excellent source of secondary zinc because they contain over 90 weight percent zinc oxide. The oxides of antimony, bismuth, and to a lesser degree cobalt, manganese, and nickel are also present in varistors. Characterization of the MOV showed that cobalt, nickel, and manganese were not present in the varistor material at concentrations greater than one weight percent. This investigation determined whether a pH selective dissolution (leaching) process can be utilized as a starting point for hydrometallurgical recycling of the zinc in MOVs. This investigation showed it was possible to selectively leach zinc from the MOV without coleaching of bismuth and antimony by selecting a suitable pH, mainly higher than 3 for acids investigated. It was not possible to leach zinc without coleaching of manganese, cobalt, and nickel. It can be concluded from results obtained with the acids used, acetic, hydrochloric, nitric, and sulfuric, that sulfate leaching produced the most desirable results with respect to zinc leaching and it is also used extensively in industrial zinc production.
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| 6. |
- Vilhav, Caroline, et al.
(författare)
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Fractional uptake of circulating tumor cells into liver-lung compartments during curative resection of periampullary cancer.
- 2018
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Ingår i: Oncology letters. - : Spandidos Publications. - 1792-1074 .- 1792-1082. ; 16:5, s. 6331-6338
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Tidskriftsartikel (refereegranskat)abstract
- Circulating tumor cells (CTCs) are able to predict outcome in patients with breast, colon and prostate cancer and appear to be promising biomarkers of pancreatic carcinoma. The aim of the present study was to demonstrate a statistically significant portal-arterial difference of CTCs during curative resection of periampullary cancer. A commercially available instrument (IsofluxR) was used to quantify blood content of CTC in 10 patients with periampullary cancer according to preoperative diagnostics. Portal and arterial blood samples (~8 ml each) were simultaneously collected intra-operatively following surgical dissection prior to division of the pancreas for tumor removal. Quantitative CTC analyses were performed according to standardized protocols for immune-magnetic enrichment of CTC. Flow cytometry was applied for qualitative evaluations of various CTC markers in 7 patients. There was a statistically significant difference in the number of CTCs collected in the portal blood [58±14 cells per 100 ml; mean ± standard error (SE)] vs. arterial blood [24±7 cells per 100 ml (SE), P<0.025]. A fractional uptake of ≥40% across liver and lung compartments of assumed malignant CTC was estimated to correspond to the appearance of ~410 tumor cells per minute during pancreatic resections based on estimated hepatic blood flow, measured tumor cell mass and tumor cell proliferation activity. Complications in the collection of portal blood were not observed. A significant uptake across liver or lung compartments of potentially malignant tumor CTCs from periampullary carcinoma may represent a model to capture, define and characterize cell clones with metastatic potential in liver and lung tissues following surgical resection.
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| 7. |
- Ylmén, Rikard E, 1982, et al.
(författare)
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Recovery of phosphorous from industrial waste water by oxidation and precipitation
- 2018
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Ingår i: Environmental Technology (United Kingdom). - : Informa UK Limited. - 1479-487X .- 0959-3330. ; 39:15, s. 1886-1897
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the development of a method for recovery of phosphorous from one of the waste waters at an Akzo Nobel chemical plant in Ale close to Göteborg. It was found that it is possible to transform the phosphorous in the waste water to a saleable product, i.e. a slowly dissolving fertilizer. The developed process includes oxidation of phosphite to phosphate with hydrogen peroxide and heat. The phosphate is then precipitated as crystalline struvite (ammonium magnesium phosphate) by the addition of magnesium chloride. The environmental impacts of the new method were compared with those of the current method using life cycle assessment. It was found that the methodology developed in this project was an improvement compared with the current practice regarding element resource depletion and eutrophication. However, the effect on global warming would be greater with the new method. There could however be several ways to decrease the global warming effect. Since most of the carbon dioxide emissions come from the production of magnesium chloride from carbonates, changing to utilization of a magnesium chloride from desalination of seawater or from recycling of PVC would decrease the carbon footprint significantly.
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