| 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. |
- Bader Eddin, Mohamad, et al.
(författare)
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A sound insulation prediction model for floor structures in wooden buildings using neural networks approach
- 2021
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Ingår i: Proceedings of INTER-NOISE 2021 - 2021 International Congress and Exposition of Noise Control Engineering. - 0736-2935. - 9781732598652
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Reliable prediction tools are yet to be developed for estimating the accurate acoustic performance of lightweight structures, which are vital especially in the design process. This paper presents a sound insulation prediction model based on artificial Neural Networks (NN) to estimate acoustic performance for airborne and impact sound insulation of floor structures. At an initial stage, the prediction model was developed and tested for a small amount of data, specifically 67 laboratory measurement curves in one third octave bands. The results indicate that the model can predict the weighted airborne reduction index Rw for various floors with a maximum error of 1 dB. The accuracy decreases with errors up to 9 dB for the weighted index for impact sound Ln,w, in cases of complex floor configurations due to large error deviations in high frequency bands between the real and estimated values. The model also shows a very good accuracy in predicting the airborne and impact sound insulation curves in the low frequencies, which are of higher interest usually in building acoustics.
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| 3. |
- Flodén, Ola, et al.
(författare)
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Robust prediction metrics for structure-borne noise in timber buildings
- 2021
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Ingår i: Proceedings of INTER-NOISE 2021 - 2021 International Congress and Exposition of Noise Control Engineering. - 0736-2935. - 9781732598652
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- An investigation of velocity-based vibration metrics for predicting structure-borne noise in timber buildings is presented in the paper. The purpose of the study is to derive a robust metric based solely on the vibration response and with a known correlation to the acoustic response in a room. Such a measure is useful for establishing simplified numerical prediction models and for making robust concept assessments. A set of 100 models, based on an example case of a massive-timber building, was generated as a statistical basis for evaluating the degree of correlation between noise and vibration metrics for sound transmission between storeys. The noise metric was calculated by spatial averaging of the sound pressure in the receiver room, while the vibration metric was calculated by spatial averaging of the normal-to-surface-direction velocity in the receiver room. The degree of correlation for linear regression between the noise and vibration metrics was evaluated for various frequency bands. Generally, a high degree of correlation was observed.
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