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- Solem, C., et al.
(författare)
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Phosphoglycerate Mutase Is a Highly Efficient Enzyme without Flux Control in Lactococcus lactis
- 2010
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Ingår i: Journal of Molecular Microbiology and Biotechnology. - : S. Karger AG. - 1464-1801 .- 1475-3774. ; 18:3, s. 174-180
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Tidskriftsartikel (refereegranskat)abstract
- The glycolytic enzyme phosphoglycerate mutase (PGM), which catalyzes the conversion of 3-phosphoglycerate to 2-phosphoglycerate, was examined in Lactococcus lactis with respect to its function, kinetics and glycolytic flux control. A library of strains with PGM activities ranging between 15-465% of the wild-type level was constructed by replacing the native promoter of pgm with synthetic promoters of varying strengths. The specific growth rate and glucose flux were found to be maximal at the wild-type level at which PGM had no flux control. Low flux control of PGM was found on mixed acid fluxes at highly reduced PGM activities. At the wild-type level PGM operated very far from V-max. Consequently, in a strain with only 15% PGM activity, the catalytic rate of PGM was almost six times higher than in the wildtype. K-m of PGM for 3-phosphoglycerate was 1.0 m M and k(cat) was 3,200 s(-1). The L. lactis PGM was dependent on 2,3-bisphosphoglyceric acid for activity, which showed that the enzyme is of the dPGM type in accordance with its predicted homology to dPGM enzymes from other organisms. In conclusion, PGM from L. lactis is a highly efficient catalyst, which partially explains why this enzyme has limited control in wild-type L. lactis. Copyright (C) 2010 S. Karger AG, Basel
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| 2. |
- Song, Lin, et al.
(författare)
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In situ study of spray deposited titania photoanodes for scalable fabrication of solid-state dye-sensitized solar cells
- 2017
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Ingår i: Nano Energy. - : ELSEVIER SCIENCE BV. - 2211-2855 .- 2211-3282. ; 40, s. 317-326
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Tidskriftsartikel (refereegranskat)abstract
- Spray coating, a cost-effective and scalable technique, has been employed for fabricating titania films for solidstate dye-sensitized solar cells (ssDSSCs). The spray deposition of films is inherently based on kinetic processes with great complexity, which poses great challenges in its understanding. In the present work, the kinetics of the structure evolution of deposited films are investigated by in situ grazing-incidence small-angle x-ray scattering during spray deposition. The spray-solution is prepared via a polystyrene-block-polyethylene oxide (PS-b-PEO) template assisted sol-gel synthesis. It is turned into nanostructured titania/PS-b-PEO composite films via spray deposition. The information about nanostructure length scales of the composite film is obtained in real-time and in situ, revealing the morphological evolution during the spray deposition. The resulting mesoporous titania films serve as photoanodes of ssDSSCs, which couple with the solution-cast hole transport layer to form the active layers. The well working ssDSSCs demonstrate the successful use of spray deposition as a large-scale manufacturing process for photoanodes.
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| 5. |
- McGurk, C., et al.
(författare)
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A comparative analysis of moving average filter and Kalman filter for large diesel engine test cell back-pressure control
- 2023
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Ingår i: International Journal of Engine Research. - : Sage Publications. - 1468-0874 .- 2041-3149. ; 24:7, s. 3186-3196
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Tidskriftsartikel (refereegranskat)abstract
- Diesel engine combustion releases many harmful components, thus there are continuous efforts into improving the efficiency of these engines and reducing the harmful gasses and particulates to meet the emission authorities targets. To develop and sell new engine-related products, these engines are required to run and to be audited in diesel engine test cells. A critical measurement for benchmark testing is the exhaust back-pressure, which is the resultant exhaust flow from the engine and a product of the air and fuel consumed. The back-pressure is controlled by restricting the flow of the exhaust using a butterfly valve and this pressure must be set to the defined limits to ensure engine compliance. Setting this limit takes time and consumes large volumes of fuel, which causes additional emissions. Therefore, a feedback control solution to regulate this back-pressure is desirable. In current practice, a moving average filter is used on two commercial standard engine softwares – SGS CyFlex® and AVL Puma 2® Data Acquisition and Control Systems to provide a useful signal for feedback control. Considering the presence of erratic noise associated with the back-pressure measurement, a Kalman Filter with tunable measurement uncertainty and process noise gains is also considered. By modifying the script in SGS CyFlex® and AVL PUMA 2®, a Kalman Filter is implemented for the first time on diesel engine test cells and a comparative analysis between the performance of the two filters is provided. Both filters effectively reduce the noise of the system, with the Kalman Filter showing a closer tracking to the desired system response. This demonstrates the potential of applying the Kalman Filter to provide the feedback signal for improved back-pressure control that could reduce the fuel consumption during testing, thereby makes testing process more economical and environment friendly. The script and results presented in this work will open up the opportunities of applying Kalman filtering method’s in various engine testing functions, which will have broader impact in the current industrial practice.
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