| 1. |
- Abolhasani, Hasanali, et al.
(författare)
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Development of self-healable acrylic water-based environmental-friendly coating as an alternative to chromates coatings
- 2023
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Ingår i: Progress in organic coatings. - : Elsevier B.V.. - 0300-9440 .- 1873-331X. ; 176
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Tidskriftsartikel (refereegranskat)abstract
- In this study, different coating systems, including solvent-based epoxy and water-based acrylic resins, were evaluated for their potential as an alternative to chromate coatings in order to avoid Cr(VI) toxic hazards. The resins were used as either pigment-free coatings or were formulated with 20-wt% zinc/aluminum pigments. The coatings were subsequently applied on galvanized ST12 steel plates and their corrosion resistance was investigated by electrochemical impedance spectroscopy (EIS) evaluations. The effect of the binder and pigment type on the impact resistance of two different polymeric coatings was also evaluated. The results of impact tests revealed completely peeled film from the substrate for epoxy coatings. However, under the same experimental conditions, very few small cracks were created in water-based acrylic coatings for both pigmented and pigment-free cases. In addition, some other parameters such as drying time and coating cost were taken into account to select a good alternative to chromate coatings. The results of this work can facilitate the introduction of an inexpensive environmentally friendly acrylic coating as a promising self-healing alternative to chromate coating.
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| 2. |
- Davoodi, Ali, 1984
(författare)
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DEM Modelling of Vibratory Screens
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In Sweden, about 100 million tons of aggregate is used for road, railway, and concrete every year. Crushing is the main process for producing aggregate material in different fractions. The production process is divided into two sub-processes: comminution or size reduction and classification. The vibratory screen is one of the separation machines used to make a final separation to produce the products based on a grade or a size range. In an industry where logistics plays an important role, the transport of unnecessary materials can be costly and it is therefore critical to screen these materials before transporting them. Industrial vibratory screens are costly and also have a substantial effect on the quality of the final product. Therefore, selecting the correct vibratory screen for the crushing plant at the outset results in a better return on investment and better quality products. The main aim of this research is to understand the screening process in different conditions such as different particle size distribution (PSD) and different feed rates. The first step towards achieving the screening model is to understand the influence of different machine parameters and material properties in the screening performance. Some of these parameters have been studied in this research, such as the motion type, the material of the screen media, and the aperture shape. The Discrete Element Method (DEM) has been used to study these parameters with the idea that by using DEM simulation the particle-to-particle and particle-to-geometry interaction can be studied in a way that is impossible to achieve by real experiments. The study results show that some of the factors have a greater influence on screening, such as the effect of the motion type for the different slope of the deck. Elliptical motion is more efficient compared to linear motion. Also, the aperture shape in different parts of the screen deck has a different effect when using a single-layer or multi-layer material in the feeding point. The result of this research needs further investigation to study the effect of the interaction between different factors before achieving the complete screen model. Another achievement of this research work is to investigate the validation of DEM modelling in screening performance by using a laboratory-scale vibratory screen.
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| 3. |
- Davoodi, Ali, 1984, et al.
(författare)
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Investigating the effect of the feeding arrangement on screen media wear and screening efficiency by using DEM
- 2021
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Ingår i: Minerals Engineering. - 0892-6875. ; in press
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Tidskriftsartikel (refereegranskat)abstract
- The discrete element method (DEM) is an effective tool for studying particles and equipment interactions in comminution and classification processes. Comminution and classification process performances are dependent on the operational conditions of different units. For screens, the performance of the particle separation is affected by the wear on the screening media. This work aims to study how screening performance, along the deck, is affected by different feeding arrangements, and how it influences screen media wear. A series of DEM simulations were configured to different feeding arrangements and validated with data from a crushing plant. The simulation results and process data show how screen media wear patterns can appear in a different section of the screen and how significant their effect is on the screening performance along the deck.
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| 4. |
- Davoodi, Ali, 1984, et al.
(författare)
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Validation of a DEM model of screening performance
- 2021
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Ingår i: Minerals Engineering. - 0892-6875. ; in press
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Tidskriftsartikel (refereegranskat)abstract
- The discrete element method (DEM) is particularly suited to modelling screening processes in the minerals processing industry, since the control and optimisation of screen processes are still limited due to a lack of their fundamental understanding and the number of different design variables and machine parameters that affect the processes. The advantage of using DEM for assessing screening performance is the possibility of visualising particle behaviour in three dimensions along with the screen media. This study shows how the DEM can be used to analyse different screen machine parameters and material properties for further development. The effects of operational conditions and geometry on the screen performance are studied by a series of DEM simulations and experimental tests using a special laboratory screen. The simulations of screen performance are implemented over a variety of structural parameters, including screen width, aperture size, inclination angle and motion type. The results are analysed by distributions of percentage passing and other flow information, such as particle volume and velocities along the screen deck and the particle size distribution. The simulation results are useful for the development of a better understanding of the process and the control of the screen to create a predictive simulation model that can be used in dynamic process simulations of crushing and screening plants.
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| 5. |
- Klauson, Artur, et al.
(författare)
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A case study of printed circuit boards recycling by disintegrator technology
- 2024
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Ingår i: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 2989:1
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Konferensbidrag (refereegranskat)abstract
- The constant accumulation of Waste Electric and Electronic Equipment (WEEE) at an accelerating pace pose a threat to the environment and people. On the other hand, the WEEE and specifically their component Waste Printed Circuit Boards (WPCBs) are rich in Precious Metals (PMs) and Base Metals (BMs), more than ten times their content in natural ores. Such an opportunity has already attracted the minerals processing industry (e.g., metallurgical companies) to the WEEE recycling problem solving. However, analogically to virgin mining, the presently more or less worthless parts of WPCBs also pose a health threat since they contain toxic pollutants. The key to efficient metal recovery from WPCBs is selective processes for fragmentation and separation which are accurate for both metals and non-metals. Fragmentation is a prerequisite for accurate separation. The closed-circuit grinding (size reduction) method is preferred in the case of WPCB processing, and a prospective technology for carrying it out is High Intensity Impact Milling (HIIM). In this paper, the HIIM (disintegrator) technology is compared with commonly known technologies for selective WPCB size reduction. The HIIM demonstrated possibility to adjust the size reduction process to different materials and replication of the initial results obtained under laboratory conditions.
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| 6. |
- Zhu, Yangzhi, et al.
(författare)
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A Microfluidic Contact Lens to Address Contact Lens-Induced Dry Eye
- 2023
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 19:11
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Tidskriftsartikel (refereegranskat)abstract
- The contact lens (CL) industry has made great strides in improving CL-wearing experiences. However, a large amount of CL wearers continue to experience ocular dryness, known as contact lens-induced dry eye (CLIDE), stemming from the reduction in tear volume, tear film instability, increased tear osmolarity followed by inflammation and resulting in ocular discomfort and visual disturbances. In this article, to address tear film thinning between the CL and the ocular surface, the concept of using a CL with microchannels to deliver the tears from the pre-lens tear film (PrLTF) to the post-lens ocular surface using in vitro eye-blink motion is investigated. This study reports an eye-blink mimicking system with microfluidic poly(2-hydroxyethyl methacrylate) (poly(HEMA)) hydrogel with integrated microchannels to demonstrate eye-blink assisted flow through microchannels. This in vitro experimental study provides a proof-of-concept result that tear transport from PrLTF to post-lens tear film can be enhanced by an artificial eyelid motion in a pressure range of 0.1–5 kPa (similar to human eyelid pressure) through poly(HEMA) microchannels. Simulation is conducted to support the hypothesis. This work demonstrates the feasibility of developing microfluidic CLs with the potential to help prevent or minimize CLIDE and discomfort by the enhanced transport of pre-lens tears to the post-lens ocular surface.
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