| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Kristan, Matej, et al.
(författare)
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The Sixth Visual Object Tracking VOT2018 Challenge Results
- 2019
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Ingår i: Computer Vision – ECCV 2018 Workshops. - Cham : Springer Publishing Company. - 9783030110086 - 9783030110093 ; , s. 3-53
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge VOT2018 is the sixth annual tracker benchmarking activity organized by the VOT initiative. Results of over eighty trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in the recent years. The evaluation included the standard VOT and other popular methodologies for short-term tracking analysis and a “real-time” experiment simulating a situation where a tracker processes images as if provided by a continuously running sensor. A long-term tracking subchallenge has been introduced to the set of standard VOT sub-challenges. The new subchallenge focuses on long-term tracking properties, namely coping with target disappearance and reappearance. A new dataset has been compiled and a performance evaluation methodology that focuses on long-term tracking capabilities has been adopted. The VOT toolkit has been updated to support both standard short-term and the new long-term tracking subchallenges. Performance of the tested trackers typically by far exceeds standard baselines. The source code for most of the trackers is publicly available from the VOT page. The dataset, the evaluation kit and the results are publicly available at the challenge website (http://votchallenge.net).
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| 4. |
- Fang, Cheng, et al.
(författare)
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Closed-loop combustion phase control for multiple combustion modes by multiple injections in a compression ignition engine fueled by gasoline-diesel mixture
- 2018
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619. ; 231, s. 816-825
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Tidskriftsartikel (refereegranskat)abstract
- Partially premixed combustion with low octane fuel aims to reduce NOx and soot emission simultaneously without fuel consumption penalty. Cylinder pressure based combustion phase control is an essential technology for partially premixed combustion. A novel closed-loop combustion phase control strategy for multiple combustion modes is proposed in the current study. The combustion modes are classified into three basic categories based on injection patterns and heat release stages: (1) with only one heat release stage; (2) with two separated heat release stages; (3) with two overlapped heat release stages. Crank angle when 50% fuel is consumed (CA50) is chosen as the combustion phase indicator for the first case. Start of combustion (SOC) of each heat release stage is the combustion phase indicator for the second case. Both SOC and CA50 are the combustion phase indicators for the third case. Each combustion phase is closed-loop controlled by a proportional–integral (PI) controller with the timing adjustments of the corresponding injection. The control strategy is verified under different operating conditions in a 1.9 L light duty diesel engine fueled by gasoline-diesel mixture (volumetric 70% gasoline, 30% diesel). The experimental results show that the control strategy is able to control the combustion phase, reduce cylinder to cylinder variations as well as cycle to cycle variations under the operating conditions with exhaust gas circulation (EGR) rates of 10% and 15%.
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| 5. |
- Fang, Cheng, et al.
(författare)
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Start of low temperature reactions detection based on motoring pressure prediction for partially premixed combustion
- 2018
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Ingår i: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311. ; 141, s. 1101-1109
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Tidskriftsartikel (refereegranskat)abstract
- Partially premixed combustion aims to reduce NOx and particulate matter emission without fuel consumption penalty. Low temperature reactions are important for the partially premixed combustion. In the current study, a self-adaptive strategy is introduced to predict the motoring pressure by means of an equivalent isentropic index. The start of the low temperature reactions is detected when the pressure difference between the measured pressure and the predicted pressure is higher than a threshold value. Experimental results show that the maximum variation between the measured and the predicted motoring pressure before the top dead center is less than 0.02 bar. It is also demonstrated that the presented detection method is able to detect the start of the low temperature reactions under different engine operating conditions with varying injection timing, injection duration, number of injections and exhaust gas recirculation rate.
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| 6. |
- Fang, Cheng, et al.
(författare)
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Study on low temperature heat release of partially premixed combustion in a heavy duty engine for real-time applications
- 2019
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Ingår i: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311. ; 148, s. 219-228
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Tidskriftsartikel (refereegranskat)abstract
- Partially premixed combustion aims to reduce NOx and particulate matter emission without fuel consumption penalty. Low temperature heat release (LTHR) is an important process to be investigated. A novel motoring pressure prediction algorithm based on variable polytropic exponents was introduced and utilized to estimate average heat transfer coefficient as well as heat dissipation for real-time applications. A series of parameters, such as start of combustion (SOC) of LTHR, crank angle of 50% heat released (CA50) during LTHR, duration of LTHR and heat amount of LTHR, were further analyzed under different engine operation conditions. The results demonstrated that: (1) the absolute motoring pressure prediction error was below 0.5 bar with a relative error below 4%; (2) the average heat released during LTHR was about 40–65 J, and the mass burned was about 1–3% of the total mass burned; (3) CA50 of LTHR was more stable than SOC of LTHR, and was a better indicator for real-time combustion phase control; (4) similar combustion phase and heat amount of LTHR could be reached by adjusting the timing of the third injection regardless the difference in timing of the second injection; (5) the combustion phase and heat amount of LTHR could be controlled by the duration of the second injection.
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