| 1. |
- Hallquist, Mattias, 1969, et al.
(författare)
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Photochemical smog in China: scientific challenges and implications for air-quality policies
- 2016
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Ingår i: National Science Review. - : Oxford University Press (OUP). - 2095-5138 .- 2053-714X. ; 3:4, s. 401-403
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Tidskriftsartikel (refereegranskat)abstract
- In large areas of China severe air pollution events pose a significant threat to human health, ecosystems and climate. Current reduction of primary emissions will also affect secondary pollutants such as ozone (O3) and particulate matter (PM), but the magnitude of the effects is uncertain. Major scientific challenges are related to the formation of O3 and secondary particulate matter including Secondary Organic Aerosols (SOA). Large uncertainties also remain regarding the interactions of soot, SOA and O3 under the influence of different SO2, NOX and VOC concentrations. To improve the understanding of these secondary atmospheric interactions in China, scientific areas of central importance for photochemically induced air pollutants have been identified. In addition to the scientific challenges, results from research need to be synthesized across several disciplines and communicated to stakeholders affected by air pollution and to policy makers responsible for developing abatement strategies. Development of these science-policy interactions can benefit from experience gained under the UN ECE Convention on Long Range Transboundary Air Pollution (LRTAP)
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| 2. |
- Havenhand, Jonathan N., 1959, et al.
(författare)
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Ecological and functional consequences of coastal ocean acidification : Perspectives from the Baltic-Skagerrak System
- 2019
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 48:8, s. 831-854
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Forskningsöversikt (refereegranskat)abstract
- Ocean temperatures are rising; species are shifting poleward, and pH is falling (ocean acidification, OA). We summarise current understanding of OA in the brackish Baltic-Skagerrak System, focussing on the direct, indirect and interactive effects of OA with other anthropogenic drivers on marine biogeochemistry, organisms and ecosystems. Substantial recent advances reveal a pattern of stronger responses (positive or negative) of species than ecosystems, more positive responses at lower trophic levels and strong indirect interactions in food-webs. Common emergent themes were as follows: OA drives planktonic systems toward the microbial loop, reducing energy transfer to zooplankton and fish; and nutrient/food availability ameliorates negative impacts of OA. We identify several key areas for further research, notably the need for OA-relevant biogeochemical and ecosystem models, and understanding the ecological and evolutionary capacity of Baltic-Skagerrak ecosystems to respond to OA and other anthropogenic drivers.
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| 3. |
- Peters, Gregory, 1970, et al.
(författare)
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Environmental Sustainability for Engineers and Applied Scientists
- 2019
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This textbook presents key theoretical approaches to understanding issues of sustainability and environmental management, perfectly bridging the gap between engineering and environmental science. It begins with the fundamentals of environmental modelling and toxicology, which are then used to discuss qualitative and quantitative risk assessment methods, and environmental assessments of product design. It discusses how business and government can work towards sustainability, focusing on managerial and legal tools, before considering ethics and how decisions on environmental management can be made. Students will learn quantitative methods while also gaining an understanding of qualitative, legal, and ethical aspects of sustainability. Practical applications are included throughout, and there are study questions at the end of each chapter. PowerPoint slides and jpegs of all the figures in the book are provided online. This is the perfect textbook on environmental studies for engineering and applied science students.
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| 4. |
- Angelin, Marcus, et al.
(författare)
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Rocket scientist for a day : Investigating alternatives for chemical propulsion
- 2012
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Ingår i: Journal of Chemical Education. - : American Chemical Society (ACS). - 0021-9584 .- 1938-1328. ; 89:10, s. 1301-1304
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Tidskriftsartikel (refereegranskat)abstract
- This laboratory experiment introduces rocket science from a chemistry perspective. The focus is set on chemical propulsion, including its environmental impact and future development. By combining lecture-based teaching with practical, theoretical, and computational exercises, the students get to evaluate different propellant alternatives. To complete the task, they need to use several important curricular concepts, such as the breaking and formation of bonds, redox reactions, and thermodynamics. They also apply basic computational electronic structure calculations to investigate the energetic content of hitherto nonexisting alternatives. Finally, actual chemical rocket propulsion is demonstrated through the assembly and testing of a model rocket motor, employing a commercially available kit. The full experiment was developed for upper-level high school classes and is completed in a 3-h lab period. The experiment, or parts of it, has also been successfully used both in undergraduate programs and continuing education for teachers.
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| 5. |
- Skedung, Lisa, 1980-
(författare)
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Tactile Perception : Role of Friction and Texture
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Tactile perception is considered an important contributor to the overall consumer experience of a product. However, what physical properties that create the specifics of tactile perception, are still not completely understood. This thesis has researched how many dimensions that are required to differentiate the surfaces perceptually, and then tried to explain these dimensions in terms of physical properties, by interconnecting human perception measurements with various physical measurements. The tactile perception was assessed by multidimensional scaling or magnitude estimation, in which methods human participants assign numbers to how similar pairs of surfaces are perceived or to the relative quantity of a specified perceptual attribute, such as softness, smoothness, coarseness and coolness. The role of friction and surface texture in tactile perception was investigated in particular detail, because typically tactile exploration involves moving (at least) one finger over a textured surface. A tactile approach for measuring friction was developed by means of moving a finger over the surfaces, mounted on a force sensor. The contribution of finger friction to tactile perception was investigated for surfaces of printing papers and tissue papers, as well as for model surfaces with controlled topography. The overarching research goal of this thesis was to study, systematically, the role of texture in tactile perception of surfaces.The model surfaces displayed a sinusoidal texture with a characteristic wavelength and amplitude, fabricated by surface wrinkling and replica molding techniques. A library of surfaces was manufactured, ranging in wavelengths from 270 nm up to 100 µm and in amplitudes from 7 nm up to 6 µm. These surfaces were rigid and cleanable and could therefore be reused among the participants. To my knowledge, this is the first time in a psychophysical experiment, that the surface texture has been controlled over several orders of magnitude in length scale, without simultaneously changing other material properties of the stimuli.The finger friction coefficient was found to decrease with increasing aspect ratio (amplitude/wavelength) of the model surfaces and also with increasing average surface roughness of the printing papers. Analytical modeling of the finger’s interaction with the model surfaces shows how the friction coefficient increases with the real contact area, and that the friction mechanism is the same on both the nanoscale and microscale. The same interaction mechanism also explains the friction characteristics of tissue paper. Furthermore, it was found that the perceptions of smoothness, coarseness, coolness and dryness are satisfactorily related to the real contact area at the finger-surface interface. It is shown that it is possible to discern perceptually among both printing papers and tissue papers, and this differentiation is based on either two or three underlying dimensions. Rough/smooth and thin/thick were the two main dimensions of surface feel found for the printing papers, whereas friction and wavelength were strongly related to the perceptual cues employed in scaling the model surfaces. These experimental results support the duplex theory of texture perception, which holds that both a “spatial sense”; used to discriminate the roughest textures from the others, and a “vibration sense”; used to discriminate among the smoother textures, are involved. The perception of what is considered rough and smooth depends on the experimental stimulus context. It is concluded that friction is important for human differentiation of surface textures below about 10 µm in surface roughness, and for larger surface textures, friction is less important or can even be neglected.The finger friction experiments also allowed the following conclusions to be drawn: (i) The interindividual variation in friction coefficients is too large to allow direct comparison; however, the trends in relative friction coefficients for a group of participants are the same. (ii) Lipids are transferred to the test surface of study, and this lowers the friction. (iii) Many of the studies point to a characteristic frequency during sliding of about 30 Hz, which is both characteristic of the resonance frequency of skin and the expected frequency associated with the fingerprints. (iv) The applied load in surface interrogation is in fact regulated in response to the friction force.The limits in tactile perception were indirectly researched by similarity scaling experiments on the model surfaces. Wrinkle wavelengths of 760 nm and 870 nm could be discriminated from untextured reference surfaces, whereas 270 nm could not. The amplitude of the wrinkles so discriminated was approximately 10 nm, suggesting that nanotechnology may well have a role to play in haptics and tactile perception.
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| 6. |
- Nimmermark, Anders, 1971
(författare)
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Facets of chemical bonding that enhance or encumber conceptual understanding
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Chemical bonding is a vast subject, rich in abstract concepts and advanced and less-advanced explanatory models that the learner has to master. In this context, the teaching of chemical bonding at the secondary school level is extremely important, as it has the potential to increase or hinder students’ further understanding of bonding.In the absence of firm knowledge and effective mental models of chemical bonding, it almost impossible to achieve significant results in any chemical field or application. In this work, which combines the pure chemistry of bonding with didactical studies, I have used database searches, questionnaires, interviews, and textbook analyses to investigate some of the more important aspect of chemical bonding.In the field of pure Science, bond length data have been analysed to ascertain the differences in bond strength between neutral and charged ligands in coordination compounds. While the bond strengths differ, the difference is not sufficiently large for the bonds to be classified as different types.In the didactical field, the conceptual models of students in South Africa and Sweden and underlying causes for these mind-sets, have been investigated. The results show that the different curricula and points of emphasis foster different patterns of understanding of the topic. One finding is that 55%–60% of the students exposed to any of the curricula have a molecular view of a salt that can be traced to visual representations of single ions or formula units of a salt. Therefore, it is important to understand how, when, and which models to use, in order to help students build a more advanced understanding of chemical bonding.
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| 7. |
- Vidal Carulla, Clara, 1985-, et al.
(författare)
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Development of Preschool Children's Executive Functions throughout a Play-Based Learning Approach That Embeds Science Concepts
- 2021
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 18:2
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Tidskriftsartikel (refereegranskat)abstract
- This study focuses on the development of executive functions in preschool children during a series of science activities. A longitudinal play-based learning intervention was designed and implemented following the design of an educational experiment. Data were collected through visual ethnography in hot situations with adult supervision. Results show how entwined the concepts of inhibitory control and cognitive flexibility are within young children's development. The development of cognitive flexibility or attention shifting readily occurred when there were fictive characters (such as the king and his royal family), but changing perspective toward a nonfictive environment (i.e., taking other children's perspectives) was a more difficult and time-consuming process. This process began in an individual perspective and expanded to acknowledging others' perspectives, then moved toward creating common perspectives or alternative narratives. Results show that science activities can be a bridge for preschool children to transfer their use of executive functions, from fairytales and games toward everyday tasks.
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| 8. |
- Carney Almroth, Bethanie, 1974, et al.
(författare)
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Circular economy could expose children to hazardous phthalates and chlorinated paraffins via old toys and childcare articles
- 2022
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Ingår i: Journal of Hazardous Materials. - : Elsevier BV. - 0304-3894 .- 2772-4166. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- The European waste framework directive encourages reuse, refurbishment and recycling of products and materials in order to reduce plastic waste. However, thousands of chemicals are used in plastic materials. Many of these are potentially toxic, and may cause hormonal and developmental disruption in children. This includes phthalates and short chain chlorinated paraffins, which are used as plasticizers and flame-retardants. European legal frameworks regulate the amounts of these substances in toys in an effort to protect children's health and safety. Currently, limits are set to 0.1% for phthalates and 0.15% for SCCPs. Here, we have investigated levels of these compounds in toys and childcare products that were purchased prior to and after legislation on stricter exposure levels was implemented (total of 157 items, 54 and 103 new and old, respectively). We found that a larger portion of older toys and items (83.5%) contained amounts that exceed legal limits, compared to newer toys and items (29.6%). Concentrations of DEHP, BBP, DIDP, and SCCPs were significantly higher in old items, and both DEHP and DINP were found at concentrations exceeding 400,000 mg/kg in several old balls, which is approximately 40% of the weight of the toy, and 400 times above the legal limit. These findings indicate that old toys have the potential to pose a greater risk to children, and that regulations can be useful tools to protect children from exposure to toxic chemicals. We also stress that the waste framework directive, which urges reuse and repurposing of objects such as second hand items used for dress-up play, can lead to continued exposure via chemicals in older items. We conclude that movement towards circular economy threatens to expose children from legacy compounds already restricted on the market if efforts are not made to remove these items from circulation.
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| 9. |
- Slunge, Daniel, 1968, et al.
(författare)
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REACH authorisation and the substitution of hazardous chemicals: The case of trichloroethylene
- 2022
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 364
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Tidskriftsartikel (refereegranskat)abstract
- Through a survey with European companies and expert interviews we study how REACH authorisation affects the phase-out of hazardous chemicals focusing on trichloroethylene, a well-studied solvent used in metal parts cleaning. We find that most of the firms have substituted trichloroethylene by perchloroethylene, which has similar chemical characteristics. This allows them to continue to use the same machines and routines at low costs. Although perchloroethylene is only classified as a suspected rather than a proven carcinogenic substance in Europe, the “improvement” as the result of much regulatory effort must be considered fairly limited, particularly in the light of less hazardous alternatives being used on the market for a long time. Our survey shows that the REACH authorisation process has some effect. Many firms cited as their main reason for substitution that they wanted to avoid the renewed application process. Still, the fact that many firms report using old machines reinforces the impression that some firms are not feeling enough pressure to modify routines and engage in a more fundamental substitution process. The results illustrate the limited effectiveness of a substance by substance approach in chemical risk management. When companies can substitute chemicals of concern to substances with similar chemical characteristics, the health and environmental objectives of chemical regulation are not achieved. An important policy conclusion is that additional incentives need to be introduced in order to realize the ambition of a non-toxic environment in the European Chemicals Strategy for Sustainability. Increased use of measures targeting broader groups of structurally similar hazardous chemicals, in combination with fees that incentivize substitution, are promising avenues for a more sustainable European chemicals strategy.
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| 10. |
- Skedung, Lisa, et al.
(författare)
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Feeling small : Exploring the Tactile Perception Limits
- 2013
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 3, s. 2617-
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Tidskriftsartikel (refereegranskat)abstract
- The human finger is exquisitely sensitive in perceiving different materials, but the question remains as to what length scales are capable of being distinguished in active touch. We combine material science with psychophysics to manufacture and haptically explore a series of topographically patterned surfaces of controlled wavelength, but identical chemistry. Strain-induced surface wrinkling and subsequent templating produced 16 surfaces with wrinkle wavelengths ranging from 300 nm to 90 mu m and amplitudes between 7 nm and 4.5 mu m. Perceived similarities of these surfaces (and two blanks) were pairwise scaled by participants, and interdistances among all stimuli were determined by individual differences scaling (INDSCAL). The tactile space thus generated and its two perceptual dimensions were directly linked to surface physical properties - the finger friction coefficient and the wrinkle wavelength. Finally, the lowest amplitude of the wrinkles so distinguished was approximately 10 nm, demonstrating that human tactile discrimination extends to the nanoscale.
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