| 1. |
- Ludwig, Frank, et al.
(författare)
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Magnetic, Structural, and Particle Size Analysis of Single- and Multi-Core Magnetic Nanoparticles
- 2014
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Ingår i: IEEE Transactions on Magnetics. - 0018-9464 .- 1941-0069. ; 50:11
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Tidskriftsartikel (refereegranskat)abstract
- We have measured and analyzed three different commercial magnetic nanoparticle systems, both multi-core and single-core in nature, with the particle (core) size ranging from 20 to 100 nm. Complementary analysis methods and same characterization techniques were carried out in different labs and the results are compared with each other. The presented results primarily focus on determining the particle size-both the hydrodynamic size and the individual magnetic core size-as well as magnetic and structural properties. The used analysis methods include transmission electron microscopy, static and dynamic magnetization measurements, and Mossbauer spectroscopy. We show that particle (hydrodynamic and core) size parameters can be determined from different analysis techniques and the individual analysis results agree reasonably well. However, in order to compare size parameters precisely determined from different methods and models, it is crucial to establish standardized analysis methods and models to extract reliable parameters from the data.
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| 2. |
- Soerensen, Anne. L., et al.
(författare)
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Eutrophication Increases Phytoplankton Methylmercury Concentrations in a Coastal Sea-A Baltic Sea Case Study
- 2016
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 50:21, s. 11787-11796
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Tidskriftsartikel (refereegranskat)abstract
- Eutrophication is expanding worldwide, but its implication for production and bioaccumulation of neurotoxic monomethylmercury (MeHg) is unknown. We developed a mercury (Hg) biogeochemical model for the Baltic Sea and used it to investigate the impact of eutrophication on phytoplankton MeHg concentrations. For model evaluation, we measured total methylated Hg (MeHgT) in the Baltic Sea and found low concentrations (39 +/- 16 fM) above the halocline and high concentrations in anoxic waters (1249 +/- 369 fM). To close the Baltic Sea MeHgT budget, we inferred an average normoxic water column HgII methylation rate constant of 2 x 10-4 d-1. We used the model to compare Baltic Seas present-day (2005-2014) eutrophic state to an oligo/mesotrophic scenario. Eutrophication increases primary production and export of organic matter and associated Hg to the sediment effectively removing Hg from the active biogeochemical cycle; this results in a 27% lower present-day water column Hg reservoir. However, increase in organic matter production and remineralization stimulates microbial Hg methylation resulting in a seasonal increase in both water and phytoplankton MeHg reservoirs above the halocline. Previous studies of systems dominated by external MeHg sources or benthic production found eutrophication to decrease MeHg levels in plankton. This Baltic Sea study shows that in systems with MeHg production in the normoxic water column eutrophication can increase phytoplankton MeHg content.
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| 3. |
- Nyholm, Tufve, et al.
(författare)
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A national approach for automated collection of standardized and population-based radiation therapy data in Sweden
- 2016
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Ingår i: Radiotherapy and Oncology. - : Elsevier BV. - 0167-8140 .- 1879-0887. ; 119:2, s. 344-350
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To develop an infrastructure for structured and automated collection of interoperable radiation therapy (RT) data into a national clinical quality registry. Materials and methods: The present study was initiated in 2012 with the participation of seven of the 15 hospital departments delivering RT in Sweden. A national RT nomenclature and a database for structured unified storage of RT data at each site (Medical Information Quality Archive, MIQA) have been developed. Aggregated data from the MIQA databases are sent to a national RT registry located on the same IT platform (INCA) as the national clinical cancer registries. Results: The suggested naming convention has to date been integrated into the clinical workflow at 12 of 15 sites, and MIQA is installed at six of these. Involvement of the remaining 3/15 RT departments is ongoing, and they are expected to be part of the infrastructure by 2016. RT data collection from ARIA (R), Mosaiq (R), Eclipse (TM), and Oncentra (R) is supported. Manual curation of RT-structure information is needed for approximately 10% of target volumes, but rarely for normal tissue structures, demonstrating a good compliance to the RT nomenclature. Aggregated dose/volume descriptors are calculated based on the information in MIQA and sent to INCA using a dedicated service (MIQA2INCA). Correct linkage of data for each patient to the clinical cancer registries on the INCA platform is assured by the unique Swedish personal identity number. Conclusions: An infrastructure for structured and automated prospective collection of syntactically inter operable RT data into a national clinical quality registry for RT data is under implementation. Future developments include adapting MIQA to other treatment modalities (e.g. proton therapy and brachytherapy) and finding strategies to harmonize structure delineations. How the RT registry should comply with domain-specific ontologies such as the Radiation Oncology Ontology (ROO) is under discussion.
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| 4. |
- Ström, Mikael, 1959, et al.
(författare)
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Transformation to Lean Product Development – Approaches at Two Automotive Suppliers
- 2012
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Ingår i: 12th International Design Conference, DESIGN 2012; Dubrovnik; Croatia; 21 May 2012 through 24 May 2012. - 1847-9162. ; , s. 113-122, s. 113-122
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Konferensbidrag (refereegranskat)abstract
- The transformation to a lean product development system was studied at two automotive suppliers. The study covers the transformation approach, the problems along the way, some early results of the transformation and a comparison between the two firms in this respect. Both strive to change their operations to add more value in their delivery to the OEM (Original Equipment Manufacturer). The results show that the transformations are experienced as positive in both firms. It is demonstrated that this success is due to methods and principles included in the lean product development framework.
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| 5. |
- Berglund, Fredrik, 1974, et al.
(författare)
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Multidisciplinary Project-based Product Development Learning in Collaboration with Industry
- 2007
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Ingår i: The 3rd International CDIO Conference, MIT, Cambridge, Massachusetts, June 11-14.
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Konferensbidrag (refereegranskat)abstract
- Developing products is a multi-disciplinary process of identifying and envisaging user needs and realizing a product offer that meets these needs. This has to be done in a cost-efficient manner, while ensuring that the developed products exceed customer expectations concerning functionality and quality, and that they stand out from competition. Running project-based education in collaboration with industry allows students to gain experiences in addressing “real” problems and skills in applying industrial working practices in an industrial context. Consequently, product development organizations deliver not just the technical design of the product but a complete product offer. This involves activities such as market analysis, product planning, industrial design and development of after-market services.Some ten years ago, Chalmers University of Technology changed its Product Development project course, which addresses these needs, in order to increase the industrial collaboration and to facilitate a more multidisciplinary project composition. The course is now open for 4th year students from many disciplines including Mechanical Engineering, Automation Engineering, Industrial Management and Industrial Design. Thus, the student teams are multidisciplinary, which enables them to take on a multi-faceted, industry-sponsored product development task. The task requires that all the phases in a product development process are carried out. The students get the opportunity to appreciate that skills possessed by other disciplines are necessary to solve a complex problem, as well as the challenges involved including differences with respect to goals, culture, and disciplinary terminology.
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| 6. |
- Crocetti, R., et al.
(författare)
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Nailed Steel Plate Connections : Strength and Ductile Failure Modes
- 2016
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Ingår i: Structures. - : Elsevier BV. - 2352-0124. ; 8, s. 44-52
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Tidskriftsartikel (refereegranskat)abstract
- This paper deals with theoretical and experimental investigations of nailed steel plate connections. For the experimental part, a total of 99 laboratory tests have been carried out in order to study failure mechanism and shear capacity of nailed steel plate connections. The testing programme comprised two nail lengths, two steel plate thicknesses and five nailing patterns. All tests related to loading of the plate in the direction of the grain of the wood. The nail patterns were designed to give ductile joint failure by yielding of the nails and/or bearing failure of the wood. The failure load was recorded and the mode and course of failure noted. For some of the specimens, deformation of the nails during loading was studied by means of an X-ray equipment. Deviations between the test results and contemporary consensus as manifested in the SS-EN 1995-1-1:2004 and the Johansen theory for ductile failure were found in several respects: development of the plastic hinges in the nails, influence of nail length, steel plate thickness and nail-to-nail and edge distances. The paper also presents an empirical equation based on multiple regression analysis of the test results was proposed as an attempt to predict the load-carrying capacity of nailed connections in shear.
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| 7. |
- Albers, E, et al.
(författare)
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Continuous estimation of product concentration with calorimetry and gas analysis during anaerobic fermentations of Saccharomyces cerevisiae
- 2002
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Ingår i: Thermochimica Acta. - 0040-6031. ; 394:1-2, s. 185-190
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Tidskriftsartikel (refereegranskat)abstract
- Product concentrations may be estimated from gas analysis or calorimetric measurements. These techniques of analysis are fast, simple, and provide a continuous output. To check the accuracy of these estimations, the anaerobic ethanol formation of an industrial strain of the yeast Saccharomyces cerevisiae was selected as a test system. Cultivations were carried out as batch cultures with different nitrogen sources (ammonium, glutamate and a mixture of amino acids) and 20 g/l of glucose as the carbon and energy source. The results showed that there was a good agreement between measured and calculated ethanol values. However, especially when using heat data the results are very sensitive to small changes in the stoichiometry of the catabolic reaction, i.e. ethanol is not the only product but there are also minor amounts of glycerol and acetate. The problems generated by these products when using heat data to calculate ethanol concentrations are discussed in detail. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 8. |
- Brandberg, T., et al.
(författare)
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Continuous fermentation of wheat-supplemented lignocellulose hydrolysate with different types of cell retention
- 2007
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Ingår i: Biotechnology and Bioengineering. - : John Wiley & Sons, Inc.. - 0006-3592 .- 1097-0290. ; 98:1, s. 80-
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Tidskriftsartikel (refereegranskat)abstract
- Medium supplementation and process alternatives for fuel ethanol production from dilute acid lignocellulose hydrolysate were investigated. Dilute acid lignocellulose hydrolysate supplemented with enzymatically hydrolysed wheat flour could sustain continuous anaerobic cultivation of Saccharomyces cerevisiae ATCC 96581 if further supplemented with ammonium sulphate and biotin. This medium composition allowed for a hexose utilisation of 73% and an ethanol production of 36 mmol l-1 h-1 in chemostat cultivation at dilution rate 0.10 h-1. Three different methods for cell retention were compared for improved fermentation of supplemented lignocellulose hydrolysate: cell recirculation by filtration, cell recirculation by sedimentation and cell immobilisation in calcium alginate. All three cell retention methods improved the hexose conversion and increased the volumetric ethanol production rate. Recirculation of 75% of the bioreactor outlet flow by filtration improved the hexose utilisation from 76% to 94%. Sedimentation turned out to be an efficient method for cell separation; the cell concentration in the reactor was 32 times higher than in the outflow after 60 h of substrate feeding. However, chemostat and continuous cell recirculation cultures became severely inhibited when the dilution rate was increased to 0.20 h-1. In contrast, an immobilised system kept producing ethanol at a stable level also at dilution rate 0.30 h-1. Biotechnol. Bioeng. 2007; 98: 80-90. © 2007 Wiley Periodicals, Inc.
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| 9. |
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| 10. |
- Coureau, J. L., et al.
(författare)
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Elastic layer model for application to crack propagation problems in timber engineering
- 2006
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Ingår i: Wood Science and Technology. - : Springer Science and Business Media LLC. - 1432-5225 .- 0043-7719. ; 40:4, s. 275-290
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Tidskriftsartikel (refereegranskat)abstract
- A fracture mechanics model for analysis of crack initiation and propagation in wood is defined and applied. The model has the advantage of being simple, yet it enables reasonably general and accurate analysis commonly associated with more complex models. The present applied calculations are made by means of the finite element method and relate to progressive cleavage fracture along grain. The calculations concern a tapered double cantilever beam specimen and an end-notched beam. Comparisons are made of experimental test results. The fracture properties of the wood are modelled by means of a very thin linear elastic layer located along the crack propagation path. The properties of the layer are such that the strength and fracture energy of the wood are represented correctly. This makes a single linear elastic calculation sufficient for strength prediction. Both crack development and pre-existing cracks can be analyzed. Both material strength and fracture energy and stiffness are taken into account, their relative influence on structural strength being different for different elements. The fracture layer is in the finite element context represented by joint elements. Propagation of a crack can be analyzed either by a series of elastic calculations corresponding to different crack lengths or by use of a finite element code for non-linear analysis. The computational results include sensitivity analysis with respect to the influence of the various material parameters on structural strength.
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