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- Ahlskog, Mats, 1970-
(författare)
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Supporting pre-development of new manufacturing technologies
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In today’s tough industrial environment, efficient development of new products and new manufacturing solutions is necessary to stay competitive on a global market. Manufacturing companies use substantial money and development resources to develop new products. However, the resources spent on finding and implementing emerging manufacturing technologies are much more limited. This is often the case even though it is well known that a way of competing on a global market is through the introduction of new manufacturing technologies that can improve product quality as well as contribute to reducing manufacturing time, resulting in reduced product price and in the end increased profit.When introducing new manufacturing technologies, different challenges arise such as lack of knowledge, involvement of an external equipment supplier, etc. In addition, time-to-volume is critical when introducing new manufacturing technologies in a manufacturing context. To be able to have a fast ramp-up, manufacturing technology needs to be mature enough and at the same time meet all requirements. Efficient introduction of new manufacturing technologies requires that pre-development activities have been performed in advance.Previous research in this area highlights a lack of knowledge and solutions regarding pre-development of new manufacturing technologies. Such pre-development is important in order to have a successful introduction, fast time-to-volume and production system development. Based on these challenges, the objective of the research presented in this thesis is to develop support for pre-development of new manufacturing technologies.The research is based on literature reviews and three empirical case studies, carried out over a two-year period of time. The first empirical case study was an exploratory case study in the manufacturing industry. The purpose of that research study was to identify critical factors forcing manufacturing companies to improve the development of manufacturing technologies.The second study was a longitudinal embedded case study in the manufacturing industry with the purpose of identifying factors that affect evaluation of new manufacturing technologies during new product development. Particular attention was given to the product development process and how it has affected the evaluation of new manufacturing technologies.Finally, the third study was a single case study in the manufacturing industry with the purpose of analysing and discussing the assessment of the maturity level of a manufacturing technology.
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| 2. |
- Werke, Mats
(författare)
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Principles for modelling of manufacturing sequences
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The manufacturing sequence influence, to a large extent, component properties like fatigue life, shape accuracy and manufacturability. By simulating the manufacturing sequence, using numerical or empirical models, and extracting important accumulated data, like residual stress, hardness and shape, the possibilities of early analysis of a design concept and the associated manufacturing sequence will increase. An established methodology has the potential of reducing physical testing and the time and costs of product design and process planning.This thesis proposes an algorithm to be used for setting up a framework of interconnected process step models. With support from the algorithm, it is possible to extract a virtual simulation sequence from a physical manufacturing sequence. Thereby, you can replicate the aggregated effects of process steps on part key features and manufacturing features. The algorithm will serve as a tool in process planning when establishing virtual manufacturing sequences. The virtual sequences should be used for virtual prediction of component properties, optimization of process parameters and evaluation of the effects of replacing, removing or adding process steps to a manufacturing sequenceThe algorithm is based on stepwise upstream selection of process steps, definition of interconnected models and selection of interconnected datasets using breadth first search. The algorithm completes existing procedures for data mapping and exchange of data between models into an overall approach for establishing virtual manufacturing sequences. Other scientific contributions are methods for modelling of deep rolling and blasting, a model material for validation of rolling and forging simulation and principles for integration of process simulation with CAD/CAM.
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| 3. |
- Andersson, Carin, 1972-
(författare)
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Evaluation of Biomarker Responses in Fish : with Special Emphasis on Gill EROD Activity
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Many chemicals present in the aquatic environment can interfere with physiological functions in fish. Exposure to chemicals can be revealed by the use of biomarkers. Induction of 7-ethoxyresorufin O-deethylase (EROD) activity is a commonly used biomarker for exposure to CYP1A inducers such as dioxins and polyaromatic hyrdrocarbons. Vitellogenin is a frequently used biomarker for estrogenic compounds in various fish species whereas a biomarker for androgens, spiggin, is only found in sticklebacks. The main objectives of this thesis were to evaluate gill EROD activity as a biomarker and the three-spined stickleback as a model species in ecotoxicological studies. EROD activities were measured in gill, liver and kidney in rainbow trout (Oncorhynchus mykiss) caged in urban areas in Sweden. EROD induction was most pronounced in the gill. Also in fish caged at reference sites, with an expected low level of known CYP1A inducers, a marked gill EROD induction was found. One suggested inducer in rural waters is humic substances (HS). To evaluate the EROD-inducing capacity of HS, three-spined sticklebacks (Gasterosteus aculeatus) were exposed to HS of natural or synthetic origin. Both kinds of HS caused significant EROD induction. Gill EROD activities were also induced in sticklebacks exposed to ethynylestradiol (EE2) and β-naphthoflavone (βNF), alone and in combinations. Production of vitellogenin was induced in sticklebacks exposed to ≥50 ng EE2/l and a significant decrease in spiggin production was observed in individuals exposed to 170 ng EE2/l. Results from this thesis further strengthen the contention that gill EROD activity is a very sensitive biomarker for CYP1A inducers and that the stickleback is a suitable biomonitoring species, especially for exposure to CYP1A inducers. The finding that not only classical CYP1A inducers but also HS and high EE2 concentrations stimulate gill EROD activity is of significance for the interpretation of biomonitoring data.
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| 4. |
- Malinovschi, Andrei, 1978-, et al.
(författare)
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Consequences of Using Post- or Prebronchodilator Reference Values in Interpreting Spirometry
- 2023
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Ingår i: American Journal of Respiratory and Critical Care Medicine. - : American Thoracic Society. - 1073-449X .- 1535-4970. ; 208:4, s. 461-471
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Tidskriftsartikel (refereegranskat)abstract
- RATIONALE: Post-bronchodilator (BD) spirometry is used for diagnosis of chronic obstructive pulmonary disease (COPD). However, pre-BD reference values are used for spirometry interpretation.OBJECTIVES: To compare the resulting prevalence rates of abnormal spirometry and study the consequences of using pre- or post-BD reference values generated within the Swedish CArdioPulmonary bioImage Study (SCAPIS) when interpreting post-BD spirometry in a general population.METHODS: SCAPIS reference values for post-BD and pre-BD spirometry were based on 10,156 and 1,498 never-smoking, healthy participants, respectively. We studied the associations of abnormal spirometry, defined by using pre- or post-BD reference values, with respiratory burden in the SCAPIS general population (28,851 individuals).MEASUREMENTS AND MAIN RESULTS: Bronchodilation resulted in higher predicted median and lower limit of normal (LLN) for FEV1/FVC ratio. The prevalence of post-BD FEV1/FVC < pre-bronchodilator LLN was 4.8% and that of post-BD FEV1/FVC < post-bronchodilator LLN was 9.9% for the general population. An additional 5.1% was identified as having an abnormal post-BD FEV1/FVC ratio and this group had more respiratory symptoms, emphysema (13.5% vs. 4.1%, p<0.001) and self-reported physician-diagnosed COPD (2.8% vs. 0.5%, p<0.001) than subjects with post-BD FEV1/FVC ratio > LLN for both pre- and post-bronchodilation).CONCLUSIONS: Pre- and post-bronchodilator spirometry reference values differ with regard to FEV1/FVC ratio. Use of post-bronchodilator reference values doubled the population prevalence of airflow obstruction; this was related to a higher respiratory burden. Using post-bronchodilator reference values when interpreting post-bronchodilator spirometry might enable identification of individuals with mild disease and be clinically relevant.
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| 5. |
- Myrelid, Andreas, 1982-
(författare)
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Essays on manufacturing-related management accounting
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In general companies continuously have to improve their operations to be able to survive in the global competition. They have to be better in utilizing their resources today compared to what they were yesterday. The production systems have changed during the 20th century and factories today do not look like they did hundred years ago. Focus has moved from mass production towards flexibility. The changes in production philosophy have not been followed by a corresponding change in different supporting functions. Research shows that many companies still use accounting methods that have not been developed since the 1930s.The purpose of this licentiate thesis is to provide perspectives on some aspects concerning the relationship between manufacturing operations management and management accounting. This will increase the knowledge and understanding of how management accounting information supports manufacturing decision making.This thesis reports findings from four studies designed to investigate the informational relationship between management accounting and operations management in companies. Results from this research shows that there are many factors to consider when choosing and designing an appropriate management accounting system. Contextual factors include market, manufacturing strategy, technology, and organization. This thesis also reports on the difficulties of making theoretically sound methods work in practice.This thesis contributes with some explanatory aspects on the practical problem and investigates some potential ways forward concerning manufacturing-related management accounting.
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