| 1. |
- Duvefelt, Kenneth B. K., et al.
(författare)
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Towards simultaneous measurements of skin friction and contact area : Results and experiences
- 2015
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Ingår i: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology. - : Sage Publications. - 1350-6501 .- 2041-305X. ; 229:3, s. 230-242
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Tidskriftsartikel (refereegranskat)abstract
- This article investigates one of the important parameters when designing for feel, namely the friction coefficient. An experiment was performed to evaluate how fringe projection could be used to investigate the topography of the fingertip, especially while in contact and sliding on a smooth surface. By allowing this smooth surface to be a small sheet of glass, a topographic camera could take pictures through it. The glass was also connected to a universal force gauge to measure normal and tangential forces from which the coefficient of friction could be calculated. The intention was to get dependable data on the forces, coefficient of friction, apparent contact area and actual contact area. This set-up was tested using 66 students who used one and three fingers in both dry and wet conditions and with a rubber glove. In order to measure natural everyday friction, they were not given any particular instructions on how to clean or slide their fingers. This method resulted in a much higher variation in friction coefficients than has been found in previous research. In particular, many higher values were noticed. This illustrates that the friction coefficient is a very hard parameter to rely on when it comes to designing surfaces for feel.
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| 2. |
- Duvefelt, Kenneth, et al.
(författare)
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Model for contact between finger and sinusoidal plane to evaluate adhesion and deformation component of friction
- 2016
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Ingår i: Tribology International. - : Elsevier. - 0301-679X .- 1879-2464. ; 96, s. 389-394
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Tidskriftsartikel (refereegranskat)abstract
- One of the main parameters affecting finger friction, friction-induced vibrations in the finger, and consequently tactility is surface topography. Recently Skedung et al. performed finger friction measurements on fine controlled surfaces. These surfaces were sinusoidal with wavelengths from 0.27 to 8.8 mu m and amplitudes from 0.007 to 6 mu m. Building on those tests an analytical model for the contact was developed to explain the differences in friction coefficient. The contact was modelled as trapezoids in a circular pattern pressed against a sinusoidal plane. Results showed that the calculated contact area and therefore friction coefficient corresponded well with the measurements. This model can be used to see how the different surface parameters influence friction.
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| 3. |
- Johannesson, Carl Michael
(författare)
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How to train and teach students in design at a technical faculty where science and applied technology is seen as prime knowledge : an example
- 2012
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- For nine years, the goal of the educational track Industrial Design Engineering (IDE) at KTH has been to prepare students for their future work as engineers, in product design or any other profession where their creative ability will be used. During their studies at IDE, we not only introduce students to their future as engineers but also prepare them for a global labour market, where companies shift from national ownership to international, where they might have to move between countries, even continents. We teach the essential technical courses but also train them in public speaking, writing, making decisions, setting priorities, dealing with meetings, and working with people from different disciplines. This approach also breeds new opportunities for the students. Whilst remaining a national educational track, the international appearance gives the IDE at KTH an individual character. What is the profile of the students applying for IDE? Can one assume that they are future designers? That is rarely their main intent, although most of the students have a common desire to express their creative abilities, to create new products and influence the future. The students' ability to communicate will deepen both in visual communication through sketching, physical modelling, computer modelling and in computer graphics. Each project involves training in presentation and report writing: Literature studies are written up as summaries; Field trips, international internship and minor field studies result in travel descriptions and weekly work reports. In the project's final presentations, the students exhibit skill in expressing themselves clearly, with a good balance between the spoken word, image and text. Project cooperation with businesses is a long-held tradition in this field of studies. In some cases, this can start as early as the bachelor thesis work, but usually begins in the fourth year in the advanced course projects as well as in collaborations with foreign universities for workshops, and in international internships. For many years IDE has had a cooperation with a Chinese manufacturer and to date ten groups of students have had the opportunity to work there as design engineers for a five-week period. In addition, a large number of the IDE students take the advantage of studying abroad on student exchange. The project courses and field trips are the result of an active collaboration with global and local manufacturers, brand organizations and universities. Visits to manufacturers constitute a unique and popular training method. Institutions and businesses contribute towards the costs of national travel and, where appropriate, subsistence. Thus the educational budget remains intact. We follow the students and feel relatively up to date on where they end up after their exams. We can venture to say that a combination of the IDE education and their own ability has given them good, interesting jobs in well-known large companies as well as in lesser-known but equally interesting companies. The majority go on to gain experience in any of the multinational Swedish companies such as Ericsson, Scania, Volvo, Kinnevik, IKEA, Electrolux, Alfa Laval, H&M, ABB, Vattenfall, Atlas Copco, and others. Many work in design companies or major engineering consultancies. Ultimately, the future looks bright for those graduating the IDE!
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| 4. |
- Johannesson, Carl Michael
(författare)
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Knowledge through internship : an example of cooperation between a Chinese manufacturer and KTH, Royal Institute of Technology
- 2010
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Ingår i: ICERI2010 Proceedings. - Valencia : IATED-Int Assoc Technology Education A& Development. - 9788461424399 ; , s. 4589-4592
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Konferensbidrag (refereegranskat)abstract
- Since 2005, students from the Department of Machine Design at KTH Technical University in Stockholm have annually been offered internship with a Chinese manufacturing company, located in Shenzhen in Guangdong Province, one of the fastest growing and most important industrial regions in China. h engineering students with the opportunity to get close to Chinese industrial conditions, to get to know Chinese culture first hand and to give the students the opportunity to work with Chinese engineers and designers. On the other hand, it has given the Chinese manufacturer an insight into how Swedish engineering students work and achieve new design proposals. Among students who have previously undergone the internship, several have ended up in positions in Swedish or multinational companies where they cooperate with Chinese companies or European ones in China. The internship has been organized by KTH in cooperation with the Chinese company Ocean Power. The draft schedule was developed at KTH and approved by the Chinese company after a few adjustments.. The schedule now constitutes an agreement and a contract that ensures that the students' work supports the pedagogical and educational goals of the education at KTH. Students prepare for their visit by implementing either a visualization project associated with the products manufactured by the company, or a technical project based on a problem assigned earlier in the semester. During the internship, an account of each group's work is sent back to Stockholm in the form of a weekly diary. Each group will also present a final report of the completed project. Since its start in 2005, a total of nine groups of students have been given the opportunity to undertake internships and practice their experiences within Chinese industry. The Chinese company has from the very beginning shown great openness and understanding of the academic rules that have to dictate the collaboration with the University.
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| 5. |
- Johannesson, Kerstin, 1955, et al.
(författare)
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Ten years of marine evolutionary biology - challenges and achievements of a multidisciplinary research initiative
- 2023
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Ingår i: Evolutionary Applications. - : Wiley. - 1752-4571. ; 16:2, s. 530-41
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Tidskriftsartikel (refereegranskat)abstract
- The Centre for Marine Evolutionary Biology (CeMEB) at the University of Gothenburg, Sweden, was established in 2008 through a 10-year research grant of 8.7 m€ to a team of senior researchers. Today, CeMEB members have contributed >500 scientific publications, 30 PhD theses and have organised 75 meetings and courses, including 18 three-day meetings and four conferences. What are the footprints of CeMEB, and how will the centre continue to play a national and international role as an important node of marine evolutionary research? In this perspective arcticle we first look back over the 10 years of CeMEB activities and briefly survey some of the many achievements of CeMEB. We furthermore compare the initial goals, as formulated in the grant application, with what has been achieved, and discuss challenges and milestones along the way. Finally, we bring forward some general lessons that can be learnt from a research funding of this type, and we take also look ahead, discussing how CeMEB’s achievements and lessons can be used as a springboard to the future of marine evolutionary biology.
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| 6. |
- Knutsen, Halvor, et al.
(författare)
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Combining population genomics with demographic analyses highlights habitat patchiness and larval dispersal as determinants of connectivity in coastal fish species
- 2022
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 31:9, s. 2562-2577
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Tidskriftsartikel (refereegranskat)abstract
- Gene flow shapes spatial genetic structure and the potential for local adaptation. Among marine animals with non-migratory adults, the presence or absence of a pelagic larval stage is thought to be a key determinant in shaping gene flow and the genetic structure of populations. In addition, the spatial distribution of suitable habitats is expected to influence the distribution of biological populations and their connectivity patterns. We used whole genome sequencing to study demographic history and reduced representation (ddRAD) sequencing data to analyze spatial genetic structure in broadnosed pipefish (Syngnathus typhle). Its main habitat is eelgrass beds, which are patchily distributed along the study area in southern Norway. Demographic connectivity among populations was inferred from long-term (~30 year) population counts that uncovered a rapid decline in spatial correlations in abundance with distance as short as ~2 km. These findings were contrasted with data for two other fish species that have a pelagic larval stage (corkwing wrasse, Symphodus melops; black goby, Gobius niger). For these latter species, we found wider spatial scales of connectivity and weaker genetic isolation-by-distance patterns, except where both species experienced a strong barrier to gene flow, seemingly due to lack of suitable habitat. Our findings verify expectations that a fragmented habitat and absence of a pelagic larval stage promote genetic structure, while presence of a pelagic larvae stage increases demographic connectivity and gene flow, except perhaps over extensive habitat gaps.
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| 7. |
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| 8. |
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| 9. |
- Skedung, Lisa, et al.
(författare)
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Tactile perception : Finger friction, surface roughness and perceived coarseness
- 2011
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Ingår i: Tribology International. - : Elsevier BV. - 0301-679X .- 1879-2464. ; 44:5, s. 505-512
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Tidskriftsartikel (refereegranskat)abstract
- Finger friction measurements performed on a series of printing papers are evaluated to determine representativeness of a single individual. Results show occasionally large variations in friction coefficients. Noteworthy though is that the trends in friction coefficients are the same, where coated (smoother) papers display higher friction coefficients than uncoated (rougher) papers. The present study also examined the relationship between the measured friction coefficients and surface roughness to the perceived coarseness of the papers. It was found that both roughness and finger friction can be related to perceived coarseness, where group data show that perceived coarseness increases with increasing roughness.
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| 10. |
- Wang, Lixin, et al.
(författare)
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Effect of surface roughness on attachment ability of locust Locusta migratoria manilensis
- 2015
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Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 332, s. 694-701
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Tidskriftsartikel (refereegranskat)abstract
- To explore how surface roughness affects locust's attachment ability, friction force of locust Locusta migratoria manilensis on substrates with variable roughness was measured with an insect micro-force measurement system. Extensive values of the friction force were acquired, respectively exhibiting the trends of inverted parabola variation, linear pattern growth and saturation period with the increased surface roughness. Obviously small values of the friction force were generated by locusts on substrates possessing a particular roughness range. The morphology and structure of locust attachment organ were examined and quantitively analyzed with a scanning electron microscope. Based on the acquired structure information, a schematic was proposed to explain the interaction between the attachment organ and the surface irregularity, also a mechanical analysis was conducted to present the effect of surface asperity on locust's claw tip. Results demonstrated that surface roughness with appropriate values can considerably reduce locust's attachment ability via simultaneously restricting the generation of mechanical interlock and adhesive attachment. The achieved conclusion gives a further interpretation to friction behavior of insect on variable substrates, also provides theory for biomimetic designing a slippery plate utilized for trapping plague locusts.
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