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| 2. |
- Zhu, Xuefeng, et al.
(författare)
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Article Non-coding 7S RNA inhibits transcription via mitochondrial RNA polymerase dimerization
- 2022
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Ingår i: Cell. - : Elsevier BV. - 0092-8674 .- 1097-4172. ; 185:13
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Tidskriftsartikel (refereegranskat)abstract
- The mitochondrial genome encodes 13 components of the oxidative phosphorylation system, and altered mitochondrial transcription drives various human pathologies. A polyadenylated, non-coding RNA molecule known as 7S RNA is transcribed from a region immediately downstream of the light strand promoter in mammalian cells, and its levels change rapidly in response to physiological conditions. Here, we report that 7S RNA has a regulatory function, as it controls levels of mitochondrial transcription both in vitro and in cultured human cells. Using cryo-EM, we show that POLRMT dimerization is induced by interactions with 7S RNA. The resulting POLRMT dimer interface sequesters domains necessary for promoter recognition and unwinding, thereby preventing transcription initiation. We propose that the non-coding 7S RNA molecule is a component of a negative feedback loop that regulates mitochondrial transcription in mammalian cells.
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| 3. |
- Astafieva, M, et al.
(författare)
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Development of living organisms on the lava-water interface of Palaeoproterozoic Ongeluk lavas of South Africa
- 2008
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Ingår i: Proceedings of the International Society for Optical Engineering, conference on Instruments, methods, and missions for astrobiology XI: 12-14 August. - : SPIE. ; 7097
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Konferensbidrag (refereegranskat)abstract
- An investigation of the Early Proterozoic pillow lavas of South-Africa shows that the lava-water boundary is very interesting from the point of view of bacterial paleontology. In the pillow selvages corresponding to this boundary, forms such as bacteria (including cyanobacteria) developed. Cyanobacterial or bacterial mats formed and probably even such highly organized forms as eukaryotes existed.
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| 4. |
- Astaneh, Majid, 1990, et al.
(författare)
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Calibration Optimization Methodology for Lithium-Ion Battery Pack Model for Electric Vehicles in Mining Applications
- 2020
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Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 13:14
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Tidskriftsartikel (refereegranskat)abstract
- Large-scale introduction of electric vehicles (EVs) to the market sets outstanding requirements for battery performance to extend vehicle driving range, prolong battery service life, and reduce battery costs. There is a growing need to accurately and robustly model the performance of both individual cells and their aggregated behavior when integrated into battery packs. This paper presents a novel methodology for Lithium-ion (Li-ion) battery pack simulations under actual operating conditions of an electric mining vehicle. The validated electrochemical-thermal models of Li-ion battery cells are scaled up into battery modules to emulate cell-to-cell variations within the battery pack while considering the random variability of battery cells, as well as electrical topology and thermal management of the pack. The performance of the battery pack model is evaluated using transient experimental data for the pack operating conditions within the mining environment. The simulation results show that the relative root mean square error for the voltage prediction is 0.7–1.7% and for the battery pack temperature 2–12%. The proposed methodology is general and it can be applied to other battery chemistries and electric vehicle types to perform multi-objective optimization to predict the performance of large battery packs.
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| 5. |
- Astaneh, Majid, 1990, et al.
(författare)
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Finite-size effects on heat and mass transfer in porous electrodes
- 2022
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Ingår i: International Journal of Thermal Sciences. - : Elsevier BV. - 1290-0729. ; 179
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Tidskriftsartikel (refereegranskat)abstract
- In thin electrode applications, as the ratio of the obstacle size with respect to the system size increases, issues such as finite-size effects become more influential in the transport of heat and mass within a porous structure. This study presents a numerical approach to evaluate the finite-size effects on the heat and mass transfer in porous electrodes. In particular, numerical simulations based on the lattice Boltzmann method (LBM) are employed to analyze the pore-scale transport phenomena. Analyzing the results at both the electrode level and the pore level shows that the mass transfer performance is more influenced by the finite-size effects compared to the transfer of heat. The numerical simulations show that as the parameter m being the ratio of the electrode thickness to the particle diameter is halved, the effective diffusivity increases by 20% while the effective conductivity remains unchanged. We propose a novel analytical tortuosity–porosity (τ−ϕ) correlation as τ=[1−(1−ϕ)m+1]/ϕ where the finite-size effects are taken into account via the parameter m. Besides, particles of small size provide more uniform distributions of temperature and concentration within the porous structure with standard deviations of approximately half of the values obtained from the case made up of large particles. Our findings at the electrode level are compared with the commonly used macroscopic porosity-dependent correlations found in the literature. At the end, by performing a systematic assessment, we provide guidelines for efficient design of porous electrodes.
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| 6. |
- Astaneh, Majid, 1990, et al.
(författare)
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Lithium-Ion Battery Pack Modelling for Electric Vehicles in Mining Applications Using GT-AutoLion
- 2020
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Large traction battery packs play a pivotal role in electric vehicles (EVs) to fulfill the system demand for high voltage and capacity. Therefore, accurate and robust modeling of both individual battery cells and their aggregated behavior in battery packs is of crucial importance. This presentation proposes a novel approach to integrate the validated electrochemical-thermal models of the Lithium-ion (Li-ion) cells into battery pack simulations for electric vehicle applications. The approach employs the calibration optimization methodology that utilizes experimental measurements for battery cells and for the battery pack under realistic operating conditions in mining applications. The random variability of battery cells, as well as electrical topology and thermal management of the pack have been considered in the present study to mimic the actual behavior of the battery pack under consideration. The simulations were carried out in GT-AutoLion and the optimizations were performed using GT-SUITE direct optimizer. The experimental data were provided by Northvolt AB, a leading European manufacturer of the next-generation Li-ion battery cells and complete battery systems. The proposed methodology is general and can be applied to other battery chemistries and electric vehicle types to perform multi-objective optimization to predict the performance of large battery packs.
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