| 1. |
- Dahl, Martin, 1984-, et al.
(författare)
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A 2,000-Year Record of Eelgrass (Zostera marina L.) : Colonization Shows Substantial Gains in Blue Carbon Storage and Nutrient Retention
- 2024
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Ingår i: Global Biogeochemical Cycles. - : John Wiley & Sons. - 0886-6236 .- 1944-9224. ; 38:3
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Tidskriftsartikel (refereegranskat)abstract
- Assessing historical environmental conditions linked to habitat colonization is important for understanding long-term resilience and improving conservation and restoration efforts. Such information is lacking for the seagrass Zostera marina, an important foundation species across cold-temperate coastal areas of the Northern Hemisphere. Here, we reconstructed environmental conditions during the last 14,000 years from sediment cores in two eelgrass (Z. marina) meadows along the Swedish west coast, with the main aims to identify the time frame of seagrass colonization and describe subsequent biogeochemical changes following establishment. Based on vegetation proxies (lipid biomarkers), eelgrass colonization occurred about 2,000 years ago after geomorphological changes that resulted in a shallow, sheltered environment favoring seagrass growth. Seagrass establishment led to up to 20- and 24-fold increases in sedimentary carbon and nitrogen accumulation rates, respectively. This demonstrates the capacity of seagrasses as efficient ecosystem engineers and their role in global change mitigation and adaptation through CO2 removal, and nutrient and sediment retention. By combining regional climate projections and landscape models, we assessed potential climate change effects on seagrass growth, productivity and distribution until 2100. These predictions showed that seagrass meadows are mostly at risk from increased sedimentation and hydrodynamic changes, while the impact from sea level rise alone might be of less importance in the studied area. This study showcases the positive feedback between seagrass colonization and environmental conditions, which holds promise for successful conservation and restoration efforts aimed at supporting climate change mitigation and adaptation, and the provision of several other crucial ecosystem services. © 2024. The Authors.
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| 2. |
- Gåård, Anders, et al.
(författare)
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Införandet av Computer Based Mathematics (CBM) i ingenjörsutbildningar
- 2017
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Konferensbidrag (populärvet., debatt m.m.)abstract
- CBM är ett koncept som innebär användning av datorn och matematikprogramvaror som huvudverktyg i under-visningen. Istället för att som i traditionell undervisning kombinera handräkning med datorlabbar ligger tyngdpunkten i en CBM-kurs på datoriserade beräkningsverktyg. Härav för-flyttas fokus mot konceptförtåelse, modellering och tolkning av resultat. Vid Högskolan i Halmstad och Karlstads Universitet finns idag flera kurser baserat på CBM. Kvantitativt har införandet lett till ökad studentgenomströmning samtidigt som innehållet i kurser har ökat. Kvalitativa markörer, såsom studentens egen uppfattning om konceptuell förståelse och nyfikenhet inom ämnet, har baserat på kursvärderingar också ökat.
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| 3. |
- Ljung-Baruth, Annika, 1968-
(författare)
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A steady flameless light : the phenomenology of realness in Dorothy Canfield Fisher's The brimming cup, Her son's wife and Rough-hewn
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This study investigates the way in which experience comes to givenness in three novels by the early twentieth century American writer Dorothy Canfield Fisher (1879-1958). By utilizing a model of affectivity set up by the French phenomenologist Michel Henry, the investigation uncovers unthematized strata in The Brimming Cup (1921), Rough-Hewn (1922), and Her Son’s Wife (1926) in which subjectivity is phenomenalized as auto-affective and immanent. These strata are phenomenologically distinguished from those in which subjectivity comes to givenness as conditioned by transcendent, hyper-presentational presence. The investigation shows that in these novels, objectified presence is predominantly favored as real. Michel Henry’s distinction between affectivity and sensibility helps delineate the asymmetrical way in which affectivity as the primary, pre-self-conscious phenomenalization of subjectivity can be understood in relation to sensibility as the self-reflective, horizon-oriented phenomenalization of subjectivity. Methodologically, the study remains faithful to Edmund Husserl’s phenomenological reduction which excludes transcendent considerations of the texts.Michel Henry’s model of affectivity refutes Martin Heidegger’s understanding of subjectivity as always already thrown into a transcendent world. Nevertheless, Heidegger’s distinction between zuhanden and vorhanden is utilized in the study to clarify the integrity of a presence that cannot be posited in front of a presentational gaze. Canfieldian subjectivity is troubled by an inability to disentangle itself from this objective gaze and by its disbelief in the possibility of nonobjectified, yet real, experience. Instead subjectivity comes to validate realness as presentational vitality. Paradoxically, however, relief from suffering occurs primarily in instants that are free from phenomenalizations of life as vitalism. In such moments, subjectivity is phenomenalized as presentationally empty, existing in a nonpresentational space untouched by presentational meaning.
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| 4. |
- Löfgren, Hans, 1968-
(författare)
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A first order friction model for lubricated sheet metal forming
- 2018
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Ingår i: Theoretical and Applied Mechanics Letters. - Melville, NY : American Institute of Physics (AIP). - 2095-0349. ; 8:1, s. 57-61
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the derivation of a first order friction model for lubricated sheet metal forming. Assuming purely plastic real contacts, Newton's law of viscosity, and a square root behavior of the hydrodynamic coefficient of friction with respect to the hydrodynamic Hersey parameter an analytic model is found. The model predicts the coefficient of friction as a function of the relative pressure, the relative Hersey parameter and the real contact coefficient of friction. Questions about local and global friction are raised in the validation of the model against flat tool sheet experiments. For some flat tool sheet experiments reasonable agreements are obtained assuming a rigid punch pressure distribution. The restricted number of user inputs makes the model useful in early tool design simulations. © 2018 The Authors. Published by Elsevier Ltd on behalf of The Chinese Society of Theoretical and Applied Mechanics
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| 5. |
- Löfgren, Hans Bertil, 1968-
(författare)
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A solution to the hydrodynamic lubrication of a circular point contact sliding over a flat surface with cavitation
- 2012
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Ingår i: Theoretical and Applied Mechanics Letters. - Melville, NY : American Institute of Physics (AIP). - 2095-0349. ; 2:3
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Tidskriftsartikel (refereegranskat)abstract
- This letter presents an analytical solution to the hydrodynamic lubrication of a circular point contact sliding over a flat surface with cavitation. The solution is found by solving the Reynolds equation with Reynolds boundary condition for cavitation. The cavitation boundary is shown to be straight lines directed 108.4° against the sliding direction. The result is experimentally verified in the limit of large values of viscosity, sliding velocity and radius of a spherical ball. The solution raises questions about the coupling between cavitation and film rupture and can be used as an independent check on the validity of numerical solutions.
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| 6. |
- Philip, Rony, et al.
(författare)
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Experimental Verification of an Instrument to Test Flooring Materials
- 2018
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Ingår i: IOP Conference Series. - Bristol : Institute of Physics Publishing (IOPP).
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Konferensbidrag (refereegranskat)abstract
- The focus of this work is to validate the fluid model with different flooring materials and the measurements of an instrument to test flooring materials and its force attenuating capabilities using mathematical models to describe the signature and coefficients of the floor. The main contribution of the present work focus on the development of a mathematical fluid model for floors. The aim of the thesis was to analyze, compare different floor materials and to study the linear dynamics of falling impacts on floors. The impact of the hammer during a fall is captured by an accelerometer and response is collected using a picoscope. The collected data was analyzed using matlab least square method which is coded as per the fluid model. The finding from this thesis showed that the fluid model works with more elastic model but it doesn't work for rigid materials like wood. The importance of parameters like velocity, mass, energy loss and other coefficients of floor which influences the model during the impact of falling on floors were identified and a standardized testing method was set. © Published under licence by IOP Publishing Ltd.
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| 7. |
- Sjödén, Björn, 1977-, et al.
(författare)
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Concept-Based Modeling as a Method Combining Digital and Analogue Means for Problem-Solving
- 2023
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Ingår i: Design, Learning, and Innovation. - Cham : Springer. - 9783031313912 - 9783031313929 ; , s. 22-37
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Konferensbidrag (refereegranskat)abstract
- In this paper we present Concept-Based Modeling (CBM), an innovative pedagogical method for problem-solving in engineering education, which combines analogue and digital tools. We outline the scientific rationale for CBM and discuss how it compares to traditional teaching with respect to optimizing the pedagogical value of both analogue and digital means. CBM is based on conceptual modeling of quantities derived directly from first principles and streamlined for the use of computer algebra systems (CAS). The method was evaluated in a pilot survey in a statics course for engineering students in their freshman year at Halmstad University. We conclude that CBM improves students’ problem-solving skills by the reciprocal action between conceptual understanding and modeling of a problem. Student evaluations suggest that CBM enables students to handle more realistic problems and that CAS as a professional tool prepares them for their future working life. Future studies will address CBM for more advanced courses, as the students’ knowledge develops over time. © 2022 The Authors.
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