| 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. |
- Kristanl, Matej, et al.
(författare)
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The Seventh Visual Object Tracking VOT2019 Challenge Results
- 2019
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Ingår i: 2019 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW). - : IEEE COMPUTER SOC. - 9781728150239 ; , s. 2206-2241
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge VOT2019 is the seventh annual tracker benchmarking activity organized by the VOT initiative. Results of 81 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 as well as the standard VOT methodology for long-term tracking analysis. The VOT2019 challenge was composed of five challenges focusing on different tracking domains: (i) VOT-ST2019 challenge focused on short-term tracking in RGB, (ii) VOT-RT2019 challenge focused on "real-time" short-term tracking in RGB, (iii) VOT-LT2019 focused on long-term tracking namely coping with target disappearance and reappearance. Two new challenges have been introduced: (iv) VOT-RGBT2019 challenge focused on short-term tracking in RGB and thermal imagery and (v) VOT-RGBD2019 challenge focused on long-term tracking in RGB and depth imagery. The VOT-ST2019, VOT-RT2019 and VOT-LT2019 datasets were refreshed while new datasets were introduced for VOT-RGBT2019 and VOT-RGBD2019. The VOT toolkit has been updated to support both standard short-term, long-term tracking and tracking with multi-channel imagery. 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(1).
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| 3. |
- Bhat, Goutam, et al.
(författare)
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NTIRE 2022 Burst Super-Resolution Challenge
- 2022
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Ingår i: 2022 IEEE/CVF CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION WORKSHOPS (CVPRW 2022). - : IEEE. - 9781665487399 - 9781665487405 ; , s. 1040-1060
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Konferensbidrag (refereegranskat)abstract
- Burst super-resolution has received increased attention in recent years due to its applications in mobile photography. By merging information from multiple shifted images of a scene, burst super-resolution aims to recover details which otherwise cannot be obtained using a simple input image. This paper reviews the NTIRE 2022 challenge on burst super-resolution. In the challenge, the participants were tasked with generating a clean RGB image with 4x higher resolution, given a RAW noisy burst as input. That is, the methods need to perform joint denoising, demosaicking, and super-resolution. The challenge consisted of 2 tracks. Track 1 employed synthetic data, where pixel-accurate high-resolution ground truths are available. Track 2 on the other hand used real-world bursts captured from a handheld camera, along with approximately aligned reference images captured using a DSLR. 14 teams participated in the final testing phase. The top performing methods establish a new state-of-the-art on the burst super-resolution task.
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| 4. |
- Li, Bo, et al.
(författare)
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Experimental and numerical study of a conical turbulent partially premixed flame
- 2009
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Ingår i: Proceedings of the Combustion Institute. - : Elsevier BV. - 1540-7489. ; 32, s. 1811-1818
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Tidskriftsartikel (refereegranskat)abstract
- The structure and dynamics of a turbulent partially premixed methane/air flame in a conical burner were investigated using laser diagnostics and large-eddy simulations (LES). The flame structure inside the cone was charecterized in detail using LES based on a two-scalar flamelet model, with the mixture fraction for the mixing field and level-set G-function for the partially premixed flame front propagation. In addition, planar laser induced florescence (PLIF) of CH and chemiluminiscence imaging with high speed video were performed through a glass cone. CH and CH2O PLIF were also used to examine the flame structures above the cone. It is shown that in the entire flame the CH layer remains very thin, whereas the CH2O layer is rather thick. The flame is stabilized inside the cone a short distance above the nozzle. The stabilization of the flame can be simulated by the triple-flame model but not the flamelet-quenching model. The results show that flame stabilization in the cone is a result of premixed flame front propagation and flow reversal near the wall of the cone which is deemed to be dependent on the cone angle. Flamelet based LES is shown to capture the measured CH structures whereas the predicted CH2O structure is some-what thinner than the experiments.
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| 5. |
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| 6. |
- Li, Zhongshan, et al.
(författare)
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Turbulence and combustion interaction: High resolution local flame front structure visualization using simultaneous single-shot PLIF imaging of CH, OH, and CH2O in a piloted premixed jet flame
- 2010
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Ingår i: Combustion and Flame. - : Elsevier BV. - 0010-2180. ; 157:6, s. 1087-1096
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Tidskriftsartikel (refereegranskat)abstract
- High resolution planar laser-induced fluorescence (PLIF) was applied to investigate the local flame front structures of turbulent premixed methane/air jet flames in order to reveal details about turbulence and flame interaction. The targeted turbulent flames were generated on a specially designed coaxial jet burner, in which low speed stoichiometric gas mixture was fed through the outer large tube to provide a laminar pilot flame for stabilization of the high speed jet flame issued through the small inner tube. By varying the inner tube flow speed and keeping the mixture composition as that of the outer tube, different flames were obtained covering both the laminar and turbulent flame regimes with different turbulent intensities. Simultaneous CH/CH2O, and also OH PLIF images were recorded to characterize the influence of turbulence eddies on the reaction zone structure, with a spatial resolution of about 40 mu m and temporal resolution of around 10 ns. Under all experimental conditions, the CH radicals were found to exist only in a thin layer; the CH2O were found in the inner flame whereas the OH radicals were seen in the outer flame with the thin CH layer separating the OH and CH2O layers. The outer OH layer is thick and it corresponds to the oxidation zone and post-flame zone; the CH2O layer is thin in laminar flows; it becomes broad at high speed turbulent flow conditions. This phenomenon was analyzed using chemical kinetic calculations and eddy/flame interaction theory. It appears that under high turbulence intensity conditions, the small eddies in the preheat zone can transport species such as CH2O from the reaction zones to the preheat zone. The CH2O species are not consumed in the preheat zone due to the absence of H, O, and OH radicals by which CH2O is to be oxidized. The CH radicals cannot exist in the preheat zone due to the rapid reactions of this species with O-2 and CO2 in the inner-layer of the reaction zones. The local PLIF intensities were evaluated using an area integrated PLIF signal. Substantial increase of the CH2O signal and decrease of CH signal was observed as the jet velocity increases. These observations raise new challenges to the current flamelet type models. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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| 7. |
- Qi, Tian, et al.
(författare)
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Biomass steam gasification in bubbling fluidized bed for higher-H 2 syngas : CFD simulation with coarse grain model
- 2019
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Ingår i: International Journal of Hydrogen Energy. - : Elsevier BV. - 0360-3199. ; 44:13, s. 6448-6460
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Tidskriftsartikel (refereegranskat)abstract
- A comprehensive coarse grain model (CGM) is applied to simulation of biomass steam gasification in bubbling fluidized bed reactor. The CGM was evaluated by comparing the hydrodynamic behavior and heat transfer prediction with the results predicted using the discrete element method (DEM) and experimental data in a lab-scale fluidized bed furnace. CGM shows good performance and the computational time is significantly shorter than the DEM approach. The CGM is used to study the effects of different operating temperature and steam/biomass (S/B) ratio on the gasification process and product gas composition. The results show that higher temperature enhances the production of CO, and higher S/B ratio improves the production of H 2 , while it suppresses the production of CO. For the main product H 2 , the minimum relative error of CGM in comparison with experiment is 1%, the maximum relative error is less than 4%. For the total gas yield and H 2 gas yield, the maximum relative errors are less than 7%. The predicted concentration of different product gases is in good agreement with experimental data. CGM is shown to provide reliable prediction of the gasification process in fluidized bed furnace with considerably reduced computational time.
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| 8. |
- Qie, Zhiwei, et al.
(författare)
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Sensitive detection of atrazine in tap water using TELISA
- 2015
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Ingår i: Analyst. - : Royal Society of Chemistry (RSC). - 1364-5528. ; 140:15, s. 5220-5226
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Tidskriftsartikel (refereegranskat)abstract
- A highly sensitive flow injection analysis (FIA)-based thermal enzyme-linked immunoassay, TELISA, was developed for the rapid detection of atrazine (ATZ) in tap water. ATZ and beta-lactamase-labeled ATZ were employed in a competitive immunoassay using a monoclonal antibody (mAb). After the off-column liquid-phase competition, the mAb was captured on the Protein G Sepharose (TM) 4 Fast Flow (PGSFF) column support material. Injected beta-lactamase substrate ampicillin was degraded by the column-bound ATZ-beta-lactamase, generating a detectable heat signal. Several assay parameters were optimized, including substrate concentration, flow rates and regeneration conditions, as well as the mAb and ATZ-beta dilution ratios and concentrations. The assay linear range was 0.73-4.83 ng mL(-1) with a detection limit of 0.66 ng mL(-1). An entire heat signal requires 10 min for generation, and the cycle time is less than 40 min. The results were reproducible and stable. ATZ-spiked tap water samples exhibited a recovery rate of 103%-116%, which correlated with the UHPLC-MS/MS measurements. We attributed this significant increase in sensitivity over our previously published work to the following factors: (i) the capture of already-formed immune complexes on the column via immobilized Protein G, which eliminated chemical immobilization of the antibody; (ii) off-column preincubation allows the formation of immune complexes under nearly ideal conditions; and (iii) multiple buffers can be used to, in one case, enhance immune-complex formation and in the other to maximize enzymatic activity. Furthermore, the scheme creates a universal assay platform in which sensing is performed in the off-column incubation and detection after capture in the enzyme thermistor (ET) detector, which opens up the possibility of detecting any antigen for which antibodies were available.
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| 9. |
- Yan, Beibei, et al.
(författare)
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Structures and stabilization of low calorific value gas turbulent partially premixed flames in a conical burner
- 2010
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Ingår i: Experimental Thermal and Fluid Science. - : Elsevier BV. - 0894-1777 .- 1879-2286. ; 34:3, s. 412-419
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Konferensbidrag (refereegranskat)abstract
- Experiments are carried out on partially premixed turbulent flames stabilized in a conical burner. The investigated gaseous fuels are methane, methane diluted with nitrogen, and Mixtures of CH4, CO, CO2, H-2 and N-2, Simulating typical products from gasification of biomass, and co-firing of gasification gas with methane. The fuel and air are partially premixed in concentric tubes. Flame stabilization behavior is investigated and significantly different stabilization characteristics are observed in flames with and without the cone. Planar laser induced fluorescence (LIF) imaging of a fuel-tracer species, acetone, and OH radicals is carried out to characterize the flame structures. Large eddy simulations of the conical flames are carried out to gain further understanding of the flame/flow interaction in the cone. The data show that the flames with the cone are more stable than those without the cone. Without the cone (i.e. jet burner) the critical jet velocities for blowoff and liftoff of biomass derived gases are higher than that for methane/nitrogen mixture with the same heating values, indicating the enhanced flame stabilization by hydrogen in the mixture. With the cone the stability of flames is not sensitive to the compositions of the fuels, owing to the different flame stabilization mechanism in the conical flames than that in the jet flames. From the PLIF images it is shown that in the conical burner, the flame is stabilized by the cone at nearly the same position for different fuels. From large eddy simulations, the flames are shown to be controlled by the recirculation flows inside cone, which depends on the cone angle, but less sensitive to the fuel compositions and flow speed. The flames tend to be hold in the recirculation zones even at very high flow speed. Flame blowoff occurs when significant local extinction in the main body of the flame appears at high turbulence intensities. (C) 2009 Elsevier Inc. All rights reserved.
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| 10. |
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