The consumer electronics (CE) industry has high turnovers and a growing demand, such as on the home entertainment segment. At the same time, it generates e-waste of the order of a dozen million tons, about one quarter of the world's total. With the purpose of improving the environmental performance of businesses, the Waste Electrical and Electronic Equipment (WEEE) Directive was put in place in Europe. Given the high competitive environment of this industry, WEEE could be a clue for competitive edge. To create an environmental and economic win-win situation, however, companies have to master reverse logistics (RL). This is particularly challenging in fast clockspeed environments, as it is the case for the CE industry. In this paper, we develop a theoretically and empirically grounded diagnostic tool for assessing a CE company's RL practices and identifying potential for RL improvement, from a business perspective. To theoretically ground the tool, we combine specific CE literature with general theory on reverse logistics management and performance improvement. To empirically ground the tool, we collect field data by combining quantitative (a multiactor survey) with qualitative (interviews and company visits) methods. We demonstrate how our tool can be used to create awareness at senior management about the reverse logistics maturity state.
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Inkjet printing is a rapidly growing technology for depositing functional materials in the production of organic electronics. Challenges lie among others in the printing of high resolution patterns with high aspect ratio of functional materials to obtain the needed functionality like e.g. conductivity. μPlasma printing is a technology which combines atmospheric plasma treatment with the versatility of digital on demand printing technology to selectively change the wetting behaviour of materials. In earlier research it was shown that with μPlasma printing it is possible to selectively improve the wetting behaviour of functional inks on polymer substrates using atmospheric air plasma. In this investigation we show it is possible to selectively change the substrate wetting behaviour using combinations of different plasmas and patterned printing. For air and nitrogen plasmas, increased wetting of printed materials could be achieved on both polycarbonate and glass substrates. A minimal track width of 320 μm for a 200 μm wide plasma needle was achieved. A combination of N2 with HMDSO plasma increases the contact angle for water up from <100 to 1050 and from 320 to 460 for DEGDMA making the substrate more hydrophobic. Furthermore using N2-plasma in combination with a N2/HMDSO plasma, hydrophobic tracks could be printed with similar minimal track width. Combining both N2 -plasma and N2/HMDSO plasma treatments show promising results to further decrease the track width to even smaller values.
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We report the detection of tryptophan at sub-ppb levels for a fluorometer based on Fresnel lenses and low-cost electronics. These fluorometers can be used to detect fecal contamination in drinking water, indicated by tryptophan-like fluorescence.
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In this article we investigate the change in wetting behavior of inkjet printed materials on either hydrophilic or hydrophobic plasma treated patterns, to determine the minimum obtainable track width using selective patterned μPlasma printing. For Hexamethyl-Disiloxane (HMDSO)/N2 plasma, a decrease in surface energy of approx. 44 mN/m was measured. This resulted in a change in contact angle for water from <10 up to 105 degrees, and from 32 up to 46 degrees for Diethyleneglycol-Dimethaclylate (DEGDMA). For both the nitrogen, air and HMDSO/N2 plasma single pixel wide track widths of approx. 320 μm were measured at a plasma print height of 50 μm. Combining hydrophilic pretreatment of the glass substrate, by UV/Ozone or air μPlasma printing, with hydrophobic HMDSO/N2 plasma, the smallest hydrophilic area found was in the order of 300 μm as well.
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In order to make exoskeletons more useful for a larger variety of users, especially within healthcare, it is of utmost importance to improve its wear ability. The scope of the XoSoft project is to develop a soft, wearable and comfortable soft exoskeleton. Here we describe the partial research on the integration of textile sensors for the XoSoft soft exoskeleton. Various resistive textile sensors for knee-sensing were made. All sensors show repeatable results however, their accuracy and usability for this project are questionable.
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Covid-19 made us realize that educational practices in higher education must change AND can change. A possible solution for practicing lab work is working in a remote lab: a real lab in which students and the equipment/instruments are physically apart. The concept of printed touchless electronics was taken as the leading principle for students in the Department of Electrical Engineering of a university of applied sciences. They got the assignment to write a programming code, with which they could control a robot. This robot was supposed to draw, with conductive ink, a pattern, that could function as a printed (light) sensor. The robot was situated in the lab, the students uploaded their code from home. Via a live stream, the students could follow the movements of the robot and the pen. From a didactical perspective, the goal was to find out if the selected didactical methods: teamwork and feedback via an internet platform and working with consultation hours, had the estimated effect. An interdisciplinary team of three lecturers was composed to guide the students. Students thought that the consultation hours were very helpful. The online teamwork between the students did not work so well. In the future, students would like to have more opportunities for testing and working with the remote lab.
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Greenhouses are in need of new monitoring tools, as they size grow bigger and bigger but still using old labour intensive methods ways of caring for the crop. HiPerGreen is set out to create a new tool, which can drive onto the pre-existing heating pipes to provide a birds eye perspective for image analysis purposes. However, clear images are necessary for consistent usable data. This presentation resumes the steps taken during the reporting: the optimisation of a rail based system towards clear images. This is done through analysis of resulting images, understanding vibrations and oscillations, and finally presents results based on prototyping. Moreover, a re-design of the electronics and hardware was also introduce to facilitate prototyping. The results are promising, laying within the requirements.
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In manufacturing of organic electronics, inkjet printing as an alternative technique for depositing materials is becoming increasingly important. Aside to the ink formulations challenges, improving the resolution of the printed patterns is a major goal. In this study we will discuss a newly developed technique to selectively modify the substrate surface energy using plasma treatment as a means to achieve this goal. First, we look at the effects of the μPlasma treatment on the surface energy for a selection of plastic films. Second, we investigated the effects of the μPlasma treatment on the wetting behaviour of inkjet printed droplets to determine the resolution of the μPlasma printing technique. We found that the surface energy for all tested films increased significantly reaching a maximum after 3-5 repetitions. Subsequently the surface energy decreased in the following 8-10 days after treatment, finally stabilizing at a surface energy roughly halfway between the surface energy of the untreated film and the maximum obtained surface energy. When μPlasma printing lines, an improved wetting abillity of inkjet printed materials on the plasma treated areas was found. The minimal achieved μPlasma printed line was found to be 1 mm wide. For future application it is important to increase the resolution of the plasma print process. This is crucial for combining plasma treatment with inkjet print technology as a means to obtain higher print resolutions.
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