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| 2. |
- Arapan, Lilia, et al.
(författare)
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Highly Mass-Sensitive Thin Film Plate Acoustic Resonators (FPAR)
- 2011
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Ingår i: Sensors. - : MDPI AG. - 1424-8220. ; 11:7, s. 6942-6953
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Tidskriftsartikel (refereegranskat)abstract
- The mass sensitivity of thin aluminum nitride (AlN) film S0 Lamb wave resonators is theoretically and experimentally studied. Theoretical predictions based on modal and finite elements method analysis are experimentally verified. Here, two-port 888 MHz synchronous FPARs are micromachined and subsequently coated with hexamethyl-disiloxane(HMDSO)-plasma-polymerized thin films of various thicknesses. Systematic data on frequency shift and insertion loss versus film thickness are presented. FPARs demonstrate high mass-loading sensitivity as well as good tolerance towards the HMDSO viscous losses. Initial measurements in gas phase environment are further presented.
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| 3. |
- de Lichtenberg, Casper, et al.
(författare)
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The D1-V185N mutation alters substrate water exchange by stabilizing alternative structures of the Mn4Ca-cluster in photosystem II
- 2021
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Ingår i: Biochimica et Biophysica Acta - Bioenergetics. - : Elsevier. - 0005-2728 .- 1879-2650. ; 1862:1
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Tidskriftsartikel (refereegranskat)abstract
- In photosynthesis, the oxygen-evolving complex (OEC) of the pigment-protein complex photosystem II (PSII) orchestrates the oxidation of water. Introduction of the V185N mutation into the D1 protein was previously reported to drastically slow O2-release and strongly perturb the water network surrounding the Mn4Ca cluster. Employing time-resolved membrane inlet mass spectrometry, we measured here the H218O/H216O-exchange kinetics of the fast (Wf) and slow (Ws) exchanging substrate waters bound in the S1, S2 and S3 states to the Mn4Ca cluster of PSII core complexes isolated from wild type and D1-V185N strains of Synechocystis sp. PCC 6803. We found that the rate of exchange for Ws was increased in the S1 and S2 states, while both Wf and Ws exchange rates were decreased in the S3 state. Additionally, we used EPR spectroscopy to characterize the Mn4Ca cluster and its interaction with the redox active D1-Tyr161 (YZ). In the S2 state, we observed a greatly diminished multiline signal in the V185N-PSII that could be recovered by addition of ammonia. The split signal in the S1 state was not affected, while the split signal in the S3 state was absent in the D1-V185N mutant. These findings are rationalized by the proposal that the N185 residue stabilizes the binding of an additional water-derived ligand at the Mn1 site of the Mn4Ca cluster via hydrogen bonding. Implications for the sites of substrate water binding are discussed.
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| 4. |
- Ovchinnikov, Mikhail, et al.
(författare)
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Intercomparison of large-eddy simulations of Arctic mixed-phase clouds : Importance of ice size distribution assumptions
- 2014
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Ingår i: Journal of Advances in Modeling Earth Systems. - 1942-2466. ; 6:1, s. 223-248
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Tidskriftsartikel (refereegranskat)abstract
- Large-eddy simulations of mixed-phase Arctic clouds by 11 different models are analyzed with the goal of improving understanding and model representation of processes controlling the evolution of these clouds. In a case based on observations from the Indirect and Semi-Direct Aerosol Campaign (ISDAC), it is found that ice number concentration, N-i, exerts significant influence on the cloud structure. Increasing N-i leads to a substantial reduction in liquid water path (LWP), in agreement with earlier studies. In contrast to previous intercomparison studies, all models here use the same ice particle properties (i.e., mass-size, mass-fall speed, and mass-capacitance relationships) and a common radiation parameterization. The constrained setup exposes the importance of ice particle size distributions (PSDs) in influencing cloud evolution. A clear separation in LWP and IWP predicted by models with bin and bulk microphysical treatments is documented and attributed primarily to the assumed shape of ice PSD used in bulk schemes. Compared to the bin schemes that explicitly predict the PSD, schemes assuming exponential ice PSD underestimate ice growth by vapor deposition and overestimate mass-weighted fall speed leading to an underprediction of IWP by a factor of two in the considered case. Sensitivity tests indicate LWP and IWP are much closer to the bin model simulations when a modified shape factor which is similar to that predicted by bin model simulation is used in bulk scheme. These results demonstrate the importance of representation of ice PSD in determining the partitioning of liquid and ice and the longevity of mixed-phase clouds.
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| 5. |
- Zou, Yang, et al.
(författare)
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Assessment of stability graph method through numerical modelling of structurally controlled failure of open stopes
- 2024
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Ingår i: New Challenges in Rock Mechanics and Rock Engineering - Proceedings of the ISRM Rock Mechanics Symposium, EUROCK 2024. - : Taylor & Francis. ; , s. 1078-1084
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Konferensbidrag (refereegranskat)abstract
- The stability graph method is a widely used empirical method for dimensioning open rooms/stopes and support design based on stope geometry and stability number. This paper presents a rigorous investigation employing numerical models featuring multiple joint sets to replicate the structurally controlled failure of open stopes. The equivalent linear overbreak/slough (ELOS) in the model is calculated based on the volume of the detached blocks identified by defining thresholds for normal and shear displacements on joint planes. Modified Factor B values are proposed based on analyses of numerical models with varying critical joint set angles. It is found that the numerical simulation results align well with stability graph outcomes when using modified Factors A and B. This research has improved the understanding of the empirical stability graph method and promotes its reliability in predicting the stability state and unplanned dilution in open stopes.
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