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- Axelsson, Håkan, et al.
(författare)
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Mätning av aromatiska kolväten med DOAS. En studie av tillförlitlighets- och interferensproblem.
- 1990
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- DOAS-tekniken är en optisk fjärranalysmetod för mätning av luftföroreningar. I det projekt som här avrapporterats har tekniken utvärderats m a p mätning av lätta aromatiska kolväten. Projektet har omfattat såväl litteratur, labb och fältstudier av absorptionsegenskaper som interferenseffekter. Resultaten visar att de lätta aromatiska kolväten har ett gemensamt absorptionsband i nära UV (250-280 mm ) som med fördel kan användas i en DOAS-tillämpning. Utnyttjande detta band, kan flera av aromaterna mätas med en detektionsgräns på några µg/m3. Dock föreligger kraftiga interferenseffekter mellan i synnerhet komponenter med likartad kemisk struktur. Detta problem kan i vissa fall hanteras m h a multipel regressions analys. En förutsättning för detta är dock att inga 'okända' interferande ämnen (lös aromater) förekommer i mätsituationen.
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| 3. |
- Axelsson, Jan Peter, et al.
(författare)
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Control Design for a Bilinear System. Reachable Sets and Exact Linearization
- 1990
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Konferensbidrag (refereegranskat)abstract
- A bilinear system model of a continuous tank reactor from a biotechnology application (F. Mandenius et al., 1987) is studied. The concentrations of the substrate sugar and the product ethanol were measured on-line and utilized to control the flow-rate through the fermenter. The system can be integrated analytically making it possible to describe the reachable sets. Limited controllability is found on a line in the state space. These reachable set expressions are used to obtain a time-optimal controller that for large disturbances implies reversed control action as compared to linear control. Transformations used when applying exact linearization are described. The lack of controllability, also obtained using the Lie brackets of differential geometry, shows up as singularities in the transformations.
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| 4. |
- Axelsson, Jan Peter, et al.
(författare)
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Substrate Control of Biotechnical Fedbatch Processes. Robustness and the Role of Adaptivity
- 1990
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Konferensbidrag (refereegranskat)abstract
- Results from experiments on laboratory scale fedbatch processes are presented as well as analysis and design of the control system. The main reason for control is to track the drastic growth in feed demand during a cultivation. Variations in the amount and quality of the inocculum makes precalculated dosage schemes of limited value to obtain reproducible cultivation conditions. Two processes have been studied on a laboratory scale, production of bakers' yeast, and production of the enzyme salicylate hydroxylase using a strain of bacteria. Direct measurement was used to monitor the feed demand. A regulator structure is proposed based on an observer for the exponentially growing feed demand. It can be viewed as a modified PID regulator around a dosage scheme, but it is less sensitive to errors in the dosage scheme than conventional PID control. The a priori knowledge of the feed profile is further relaxed by introduction of adaptation of the growth rate parameter. The obtained non-linear control system has a simple structure and stability is garanteed for a wide range of initial values using the technique of Liapunov function. The linearized system is analysed in the frequency domain and the adaptation is shown to have negligible influence on the loop phase margin. The adaptive regulator is tested in simulation against real feed profiles and shows good results.
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| 7. |
- Sandman, Per-Olof, et al.
(författare)
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Morgentoilette bei dementen Alzheimer-Patienten : ein auf direkter Beobachtung beruhendes theoretisches Modell
- 1994
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Ingår i: Pflege, Die wissenschaftliche Zeitschrift für Pflegeberufe. - 1012-5302 .- 1664-283X. ; 7:4, s. 280-290
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Five hospitalized patients in different stages of Alzheimer-type dementia were monitored by unstructured, direct observations during morning care. Orem's model of nursing as a compensation for the patient's lack of self-care capabilities was used as a frame of reference for an analysis of the behaviours of patients and nurses during morning care. A 12-step classification system was developed to be used as a guide to understand and determine abilities essential for performance of morning care for demented patients. The quantitative assessment showed that none of the patients was able to manage morning care independently, but there was a wide variation in their highest level of performance
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