| 1. |
- Ainegren, Mats, 1963-, et al.
(författare)
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Effects of Aerodynamic Drag and Drafting on Propulsive Force and Oxygen Consumption in Double Poling Cross-Country Skiing
- 2022
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 54:7, s. 1058-1065
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Tidskriftsartikel (refereegranskat)abstract
- Purpose This study aimed to investigate the effects of aerodynamic drag and drafting on propulsive force (FPROP), drag area (CDA), oxygen cost (V˙O2), metabolic rate (Ė), and heart rate (HR) during roller skiing on a treadmill in a wind tunnel using the double poling technique. A secondary aim was to investigate the effects of wind versus no-wind test conditions on the same physiological parameters. Methods Ten subjects of each gender participated in the experiments. One pair of skiers of the same gender roller skied simultaneously in line with the air flow; the distance between the skiers was 2.05 m. Each pair was tested as follows: I) with wind, leading; II) with wind, drafting; and III) without wind. The treadmill inclination was 0° throughout the tests. For the wind conditions, the air velocity was similar to the treadmill belt speed: 3 to 7 m·s-1 for men and 3 to 6 m·s-1 for women. Results Drafting resulted in significantly (P < 0.05) lower FPROP,CDA, V˙O2, and Ė, compared with leading, for both genders at racing speed but not at lower speeds, whereas HR was only affected for the male skiers at racing speed. The test without wind resulted in significantly lower FPROP, V˙O2, and Ė at all tested speeds compared with the tests with wind present, whereas HR was lower only at higher speeds. Conclusions At racing speed, but not at lower speeds, the positive effects of drafting behind a skier during double poling were obvious and resulted in a lower FPROP, CDA, V˙O2, Ė, and HR. Tests without wind present put even lower demands on the skiers' physiology, which was also evident at lower speeds.
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| 2. |
- Clancy, Gunilla, 1968, et al.
(författare)
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Actionable knowledge to develop more sustainable products
- 2013
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Ingår i: 6th International Conference on Life Cycle Management, Göteborg, 25-28 August.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Companies need to develop more sustainable products to fit into more sustainable future markets, and there is need for ways to guide towards and compare sustainability already early in material or product development. How this can be handled has been studied through action research in a material development project aiming to develop wood-based materials to replace petroleum-based materials while ensuring a more sustainable product. A specific focus was put on creating actionable knowledge to facilitate innovation towards more sustainable products by translating and integrating significant product sustainability characteristics into each team member’s specific area of expertise and everyday work. The insights are now used in different other on-going projects in a textile industry setting and in relation to companies’ management systems.
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| 3. |
- Clancy, Gunilla, 1968, et al.
(författare)
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Changing from petroleum to wood-based materials: critical review of how product sustainability characteristics can be assessed and compared
- 2013
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 39, s. 372-385
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Forskningsöversikt (refereegranskat)abstract
- This paper reports on a literature survey on available approaches for the assessment of product sustainability, with a specific focus on assessing the replacement of non-renewable petroleum-based materials with renewable wood-based materials in absorbent hygiene products. The results are contrasted to needs in a specific material development project. A diverse number of methods exist that can help in assessing different product sustainability characteristics for parts of or whole product lifecycles. None of the assessment methods found include guidelines for how to make a case-specific interpretation of sustainability and there is a general lack of assessment parameters that can describe considerations in the comparison between the use of wood or petroleum as main raw material. One reason for this is lack of knowledge and/or consensus on how to describe and assess impacts of land and water use, e.g. on ecosystem services, different types of resource depletion and social impacts.
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| 4. |
- Dahlström, Christina, 1977-, et al.
(författare)
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Coating Microstructures : Binder Distributions
- 2012
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Ingår i: 12th TAPPI Advanced Coating Fundamentals Symposium Proceedings, Co-located with the 16th International Coating Science and Technology Symposium, ISCST 2012. - : Tappi. - 9781595102201 ; , s. 250-257
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Non-uniformities within the coating layer, such as porosity variations and binder distributions, are known to affect print uniformity and barrier properties. However, in the literature the results on coating microstructures are rather limited or sometimes conflicting.We obtained high quality images of coated paper cross sections using field emission scanning electron microscopy in combination with a new argon ion beam milling technique to directly observe and analyse the binder and pore distribution. This technique produces high quality images that allow microstructure characterisation of the coating layer.The binder distribution measurements showed that the binder is almost exclusively filling up the small pores, whereas the larger pores are mainly empty and depleted of binder.
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| 5. |
- Dahlström, Christina, 1977-, et al.
(författare)
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Surface Evolution of Pigment Coating
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We studied the surface evolution of coating by using a random deposition model of particles. In order to capture the real coating structure development, we included a volume exclusion effect to represent particle-particle interaction, and a levelling effect to represent surface tension effect. In this study we investigated three cases: (1) random deposition on a flat surface, (2) random deposition on a flat surface with levelling, and (3) random deposition on a rough surface with levelling.When plotting in logarithmic scale, the roughness initially increased linearly with average number of particles deposited for all three cases but reached saturation after a certain amount of deposited particles. The result resembles a ballistic deposition process where agglomerates are developed over the surface due to lateral growth. Even a flat, uniform surface creates roughness during random deposition of particles.Autocorrelation analysis showed that the correlation length continues to increase with the number of particles deposited. The aggregated structures were easily seen in the autocorrelation function.Experimental and simulated data on the rough surface were compared and they were in agreement, confirming that the coating process is essentially a random process with some local correlation in the length scale of a typical fibre width.
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| 6. |
- Hartman, Steven, 1965-
(författare)
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Unpacking the Black Box : the need for Integrated Environmental Humanities (IEH)
- 2015
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Annan publikation (populärvet., debatt m.m.)abstract
- The circumstances that have given rise to the Anthropocene concept require that we reassess our assumptions about human agency and human effects on the earth system. Human activities, and thus human choices, clearly lie at the root of the great environmental predicament of our age, which is not primarily an ecological crisis, though its ramifications are far reaching within ecological systems. Rather, it is a crisis of culture. If the humanities "are a unique repository of knowledge and insight into the rich diversity of the human experience" from which we learn to make sense of our "responses, motivations and actions" in the face of challenges, then it is risky to omit humanities knowledge from scientific assessment and consultation processes informing environmental policy.The complete article is available for free viewing on the Future Earth site: bit.ly/1QoHPeC .
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| 7. |
- Holmberg, Hans-Christer, et al.
(författare)
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Contribution of the legs to double-poling performance in elite cross-country skiers.
- 2006
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Ingår i: Medicine and science in sports and exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131 .- 1530-0315. ; 38:10, s. 1853-60
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Tidskriftsartikel (refereegranskat)abstract
- In the classical style of cross-country skiing, the double-poling (DP) technique, which is regarded as an upper-body exercise, is used on the flatter parts of a course. Limited biomechanical and physiological data are available about DP compared with other cross-country skiing techniques. The purpose of the present study was to evaluate the possible role of the lower body during DP.Eleven elite cross-country skiers performed two incremental tests using DP roller skiing at 1 degree inclination on a treadmill with or without locking the knee and ankle joints (DPLOCKED and DPFREE). Maximal and peak oxygen uptake (VO2max and VO2peak) during classic diagonal skiing and DP, respectively, were measured. In addition, heart rate, blood lactate concentration, and maximal DP velocity (Vmax) were determined. Pole-ground reaction forces and joint angles (elbow, hip, knee, and ankle) were analyzed.The skiers obtained 7.7% higher VO2peak, 9.4% higher Vmax, and 11.7% longer time to exhaustion during DPFREE compared with DPLOCKED (all P < 0.05). There was a higher heart rate and blood lactate concentration in DPLOCKED at submaximal stages (all P < 0.05), with no difference in oxygen consumption. At 85% Vmax, corresponding to approximately 81% VO2peak FREE, the differences in physiological variables were accompanied by a 13.6% higher poling frequency, a 4.9% shorter poling phase, 13.3% shorter recovery phase, and 10.9% lower relative pole force in DPLOCKED (all P < 0.05).Movements of the knee and ankle joints are an integrative part in the skillful use of the DP technique, and restriction of the motion in these joints markedly affects both biomechanical and physiological variables, impairing DP performance.
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| 8. |
- Jidesjö, Anders, 1972-, et al.
(författare)
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Trends and developments in student’s interest in Science and technology: Results from the Relevance of science education second (ROSES) study in Sweden
- 2021
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Ingår i: Science education in the light of Global Sustainable Development: Trends and Possibilities.. - Aarhus, Denmark. - 9788799592043 ; , s. 148-156
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Konferensbidrag (refereegranskat)abstract
- This paper report Swedish results from a large-scale research project called “The Relevance of Science Education Second (ROSES)” which builds on a previous study called Relevance of Science education (ROSE). The studies are concerned with student’s interest in and attitudes towards science and technology (S&T) in and outside education from a student’s perspective. ROSES builds on collaboration between researchers in countries all around the world from a notion where education is apprehended as culturally embedded, and countries face different challenges but can also share some common. In this connection, research literature points out the importance of a science literate population together with the need of the recruitment of future expertise as educational goals for S&T. As many students have problems of perceiving the relevance of S&T in school there is an international concern and research interest to investigate trends and developments. In this paper preliminary Swedish results from ROSES are presented concerned with student’s experiences of S&T lessons and what they want to learn about. Data were collected in 2020. The results indicate that there are some changes in motion but at the same time student’s interest for critical content areas seem to be robust. The results are discussed and connected with the development of theoretical perspectives concerned with science identity, modernity and science capital. The reporting is framed in a Nordic perspective.
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| 9. |
- Johansson, Helena, 1971-, et al.
(författare)
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Glömska eller ytliga fysikkunskaper : Fördjupad analys av svenska elevers sjunkande fysikresultat i TIMSS Advanced 2015
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- TIMSS Advanced (Trends in Mathematics and Science Study ) är en internationell studie som undersöker gymnasieelevers kunskaper i avancerad matematik och fysik. TIMSS Advanced har genomförts tre gånger, 1995, 2008 och 2015, och Sverige har deltagit varje gång. I 2015 års studie deltog svenska elever i årskurs 3 på naturvetenskaps-och teknikprogrammet som slutfört eller håller på att slutföra kursen matematik 4 respektive fysik 2. Resultaten visade att Sverige förbättrat sina resultat i matematik medan resultaten i fysik försämrats. Dessa resultat brukar normalt följas åt och denna rapport undersöker möjliga orsaker till de sjunkande fysikresultaten i TIMSS Advanced.
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| 10. |
- Johansson, Niklas, et al.
(författare)
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Influence of finite-sized detection solid angle on bidirectional reflectance distribution function measurements
- 2014
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Ingår i: Applied Optics. - : Optical Society of America. - 1559-128X .- 2155-3165. ; 53:6, s. 1212-1220
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Tidskriftsartikel (refereegranskat)abstract
- This paper deals with limitations and often overlooked sources of error introduced in compact double-beam goniophotometers. It is shown that relative errors in measured radiance factor, comparable to the total measurement uncertainty, can be introduced if recommended corrections are not carried out. Two different error sources are investigated, both related to the size of the detection solid angle. The first is a geometrical error that occurs when the size of the illuminated area and detector aperture are comparable to the distance between them. The second is a convolution error due to variations in radiant flux over the detector aperture, which is quantified by simulating the full 3D bidirectional reflectance distribution function (BRDF) of a set of samples with different degrees of anisotropic reflectance. The evaluation is performed for a compact double-beam goniophotometer using different detection solid angles, and it is shown that both error sources introduce relative errors of 1%–3%, depending on viewing angle and optical properties of the sample. Commercially available compact goniophotometers, capable of absolute measurements, are becoming more and more common, and the findings in this paper are therefore important for anyone using or planning to use this type of instrument.
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