This work presents a novel integrated MSF–MED thermal desalination technology and its techno-economics as compared to conventional systems such as MSF-BR, MED-TVC, MSF-OT-LT and plain MED. The new ...integrated MSF–MED benefits from (i) high top brine temperature (TBT) of natural dilution seawater feed of the once through (MSF-OT), (ii) lower pumping power of long tube MSF-LT, and (iii) the low heating steam quality and cost of MED.
The process calculation showed that the pumping power of the integrated MSF–MED is 58% lower than that of the traditional MSF-BR while it is 16%, lower than that of MED-TVC. The cost analysis showed that at subsidized oil price of 12$/bbl, the unit water cost of the integrated MSF–MED is 32% lower than that of MSF-BR and 21% lower than that of MED-TVC. The unit water cost of the integrated MSF–MED is the lowest value when the oil price is lower than 40$/bbl. This result showed the superiority of the integrated MSF–MED configuration for GCC countries since the oil price is generally subsidized. It also has a chance to utilize a diverse available energy such as waste heat and steam from backpressure or condensing turbine.
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•A novel integrated MSF-MED thermal desalination technology is developed.•Pumping power of the MSF-MED is 58 % lower than that of MSF-BR while it is 16 % lower than that of MED-TVC.•The unit water cost of the MSF-MED is 32 % lower than that of MSF-BR and 21 % lower than that of MED-TVC.•The MSF-MED is superior thermal process for GCC countries since the oil price is generally subsidized.•The MSF-MED has features to utilize a diverse of different types and different qaulity energy.
Photosynthetic water oxidation is catalyzed by a manganese–calcium oxide cluster, which experiences five “S-states” during a light-driven reaction cycle. The unique “distorted chair”-like geometry of ...the Mn4CaO5(6) cluster shows structural flexibility that has been frequently proposed to involve “open” and “closed”-cubane forms from the S1 to S3 states. The isomers are interconvertible in the S1 and S2 states, while in the S3 state, the open-cubane structure is observed to dominate inThermosynechococcus elongatus (cyanobacteria) samples. In this work, using density functional theory calculations, we go beyond the S3 +Y z state to the S3 n Y z • → S4 +Y z step, and report for the first time that the reversible isomerism, which is suppressed in the S3 +Y z state, is fully recovered in the ensuing S3 n Y z • state due to the proton release from a manganese-bound water ligand. The altered coordination strength of the manganese–ligand facilitates formation of the closed-cubane form, in a dynamic equilibrium with the open-cubane form. This tautomerism immediately preceding dioxygen formation may constitute the rate limiting step for O2 formation, and exert a significant influence on the water oxidation mechanism in photosystem II.
Rapid processing of tactile information is essential to human haptic exploration and dexterous object manipulation. Conventional electronic skins generate frames of tactile signals upon interaction ...with objects. Unfortunately, they are generally ill-suited for efficient coding of temporal information and rapid feature extraction. In this work, we report a neuromorphic tactile system that uses spike timing, especially the first-spike timing, to code dynamic tactile information about touch and grasp. This strategy enables the system to seamlessly code highly dynamic information with millisecond temporal resolution on par with the biological nervous system, yielding dynamic extraction of tactile features. Upon interaction with objects, the system rapidly classifies them in the initial phase of touch and grasp, thus paving the way to fast tactile feedback desired for neuro-robotics and neuro-prosthetics.
Ever since the discovery that Mn was required for oxygen evolution in plants by Pirson in 1937 and the period‐four oscillation in flash‐induced oxygen evolution by Joliot and Kok in the 1970s, ...understanding of this process has advanced enormously using state‐of‐the‐art methods. The most recent in this series of innovative techniques was the introduction of X‐ray free‐electron lasers (XFELs) a decade ago, which led to another quantum leap in the understanding in this field, by enabling operando X‐ray structural and X‐ray spectroscopy studies at room temperature. This review summarizes the current understanding of the structure of Photosystem II (PS II) and its catalytic centre, the Mn4CaO5 complex, in the intermediate Si (i = 0–4)‐states of the Kok cycle, obtained using XFELs.
Water oxidation reaction in nature is catalysed by the Mn4CaO5 cluster in Photosystem II. We have developed operando X‐ray crystallography and X‐ray spectroscopy methods at the X‐ray free‐electron laser facilities and applied them to understand the catalytic mechanism and associated protein dynamics in Photosystem II.
The myelination of axons by oligodendrocytes has been suggested to be modulated by experience, which could mediate neural plasticity by optimizing the performance of the circuitry. We have assessed ...the dynamics of oligodendrocyte generation and myelination in the human brain. The number of oligodendrocytes in the corpus callosum is established in childhood and remains stable after that. Analysis of the integration of nuclear bomb test-derived (14)C revealed that myelin is exchanged at a high rate, whereas the oligodendrocyte population in white matter is remarkably stable in humans, with an annual exchange of 1/300 oligodendrocytes. We conclude that oligodendrocyte turnover contributes minimally to myelin modulation in human white matter and that this instead may be carried out by mature oligodendrocytes, which may facilitate rapid neural plasticity.
The advent of machine learning‐based structure prediction algorithms such as AlphaFold2 (AF2) and RoseTTa Fold have moved the generation of accurate structural models for the entire cellular protein ...machinery into the reach of the scientific community. However, structure predictions of protein complexes are based on user‐provided input and may require experimental validation. Mass spectrometry (MS) is a versatile, time‐effective tool that provides information on post‐translational modifications, ligand interactions, conformational changes, and higher‐order oligomerization. Using three protein systems, we show that native MS experiments can uncover structural features of ligand interactions, homology models, and point mutations that are undetectable by AF2 alone. We conclude that machine learning can be complemented with MS to yield more accurate structural models on a small and large scale.
Nucleation is a fundamental part in most syntheses of ceramic materials. Yet, few techniques enable control of this step, which would offer possibilities to attain full-scale kinetic selectivity of ...the syntheses to reach novel compounds with unique properties. Herein, we present a nucleation-controlled crystallization pathway to synthesize coatings of aluminum titanate (Al 2 TiO 5 )─renowned for its low-to-negative thermal expansion─at significantly reduced temperatures than conventional solid-state techniques. Based on a kinetic study using in situ X-ray diffraction, detailed mechanistic insights into the crystallization process and phase evolutions within the Al–Ti–O system are obtained. The lowest activation energies for crystallization are given when the Al–Ti ratio is close-to-stoichiometric or Ti-enriched. Along with these compositions’ similar kinetics at the earliest stages of the transformation, a joint nucleation behavior is discovered, revealing the elemental role of titanium in nucleating the main Al 2 TiO 5 phase. Based on classical nucleation theory, we deduce the significant influence of the configurational entropy ( S config ) when crystallization occurs in the nucleation-controlled domain. Finally, peculiar transition features are observed in the Al-enriched regime during annealing at intermediate temperatures, whose causes are ascribed to the presence of secondary nucleation events and possibilities of structural relaxations in the amorphous matrixes when crystallizing.
Integrating variable and non-dispatchable renewable power generation into existing power systems will have consequences for their operation and future expansion. These impacts will depend on two ...factors: (1) the variability of the total renewable power generation on different time scales and (2) the possibilities of accurately forecasting these fluctuations. In this paper, previous research on variability assessment and forecasting of solar, wind, wave and tidal energy resources is reviewed. The aim is to summarize the state of knowledge in each area and to compare the approaches used for the respective resources. For temporal variability, methods and models used for assessing the variability are surveyed, as well as what is known about the variability at individual sites and for larger aggregates of sites. For forecasting, an overview of forecasting methods for the different resources is made, and selected forecasting methods are compared over different time horizons. An important finding is that it is hard to draw strong conclusions from the existing studies due to differences in approaches and presentation of results. There is a need for further, more coherent studies that analyze the variability for the different resources in comparable ways, using data with the same resolution, and for studies that evaluate the smoothing effect and complementarity of combinations of several renewable energy resources. For forecasting, future research should suggest ways to evaluate forecasts from different renewable energy sources in easily comparable ways, using data from the same locations or regions, with the same temporal and spatial resolution, and with comparable metrics for the forecasting errors.
Dans les années 80, Abdoulaye Mamani et Med Hondo se sont inspirés des récits oraux pour transformer Sarraounia Mangou, figure historique, en un mythe littéraire et cinématographique. Depuis lors, ...plusieurs autres types de média – chanson populaire, bande dessinée, peinture architecturale, sculpture joaillière, réseaux sociaux – reprennent à leur manière et réinscrivent dans l’imaginaire négro-africain l’épopée anti-impériale de cette monarque nigériènne. Face à cette prolifération des modes de narration, quel serait le rapport de l’oralité à l’historiographie quand le récit navigue entre plusieurs supports médiatiques, en l’occurrence scripturels, sonores, visuels, numériques? Quel rôle est assigné au griot dans ce contexte? Le présent article affirme que loin d’être de simples transcriptions de la parole du griot, les divers récits de Sarraounia s’appuient sur l’oralité non seulement comme instance achéologique de l’historiographie, mais surtout comme indice sémiologique d’interférence, d’hybridation et de différenciation.
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