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Despite the growth of renewable energy, fossil fuels dominate the global energy matrix. Due to expanding proved reserves and energy demand, an increase in natural gas power generation is predicted for future decades. Oil reserves from the Brazilian offshore Pre-Salt basin have a high gas-to-oil ratio of CO2-rich associated gas. To deliver this gas to market, high-depth long-distance subsea pipelines are required, making Gas-to-Pipe costly. Since it is easier to transport electricity through long subsea distances, Gas-to-Wire instead of Gas-to-Pipe is a more convenient alternative. Aiming at making offshore Gas-to-Wire thermodynamically efficient without impacting CO2 emissions, this work explores a new concept of an environmentally friendly and thermodynamically efficient Gas-to-Wire process firing CO2-rich natural gas (CO2 > 40%mol) from high-depth offshore oil and gas fields. The proposed process prescribes a natural gas combined cycle, exhaust gas recycling (lowering flue gas flowrate and increasing flue gas CO2 content), CO2 post-combustion capture with aqueous monoethanolamine, and CO2 dehydration with triethylene glycol for enhanced oil recovery. The two main separation processes (post-combustion carbon capture and CO2 dehydration) have peculiarities that were addressed at the light shed by thermodynamic analysis. The overall process provides 534.4 MW of low-emission net power. Second law analysis shows that the thermodynamic efficiency of Gas-to-Wire with carbon capture attains 33.35%. Lost-Work analysis reveals that the natural gas combined cycle sub-system is the main power destruction sink (80.7% Lost-Work), followed by the post-combustion capture sub-system (14% Lost-Work). These units are identified as the ones that deserve to be upgraded to rapidly raise the thermodynamic efficiency of the low-emission Gas-to-Wire process.

Observation of the greenhouse effect prompts the consideration of every possibility of reducing anthropogenic carbon dioxide emissions. One of the key methods that has been the subject of much research is Carbon Dioxide Capture and Storage. The purpose of this study was to investigate the main technologies of CO2 capture, separation, and dehydration as well as methods of its transport and methodology of selecting a suitable geological storage site. An installation of dehydration and compression of carbon dioxide captured after the post-combustion was designed at a temperature of 35 °C, a pressure of 1.51 bar, and a mass flow rate of 2.449 million tons/year, assuming that the geological storage site is located at 30 km from the capture place. For the dehydration process, a multistage compression and cooling system were applied, combined with a triethylene glycol (TEG) dehydration unit. The mass flow rate of TEG was selected as 0.5 kg/s. H2O out of the TEG unit was 26.6 ppm. The amount of energy required to compress the gas was minimized by adopting a maximum post-compression gas temperature of 95 °C for each cycle, thereby reducing plant operating costs. The total power demand was 7047 kW, 15,990 kW, and 24,471 kW, and the total received heat input was 13,880.76 kW, 31,620.07 kW, and 47,035.66 kW for 25%, 60%, and 100% plant load, respectively. The use of more compressors reduces the gas temperature downstream through successive compression stages. It also decreases the total amount of energy required to power the entire plant and the amount of heat that must be collected during the gas stream cooling process. The integration of CO2 compression and cooling system to recover heat and increase the efficiency of power units should be considered.

The first generation of forest free‐air CO₂ enrichment (FACE) experiments has successfully provided deeper understanding about how forests respond to an increasing CO₂ concentration in the atmosphere. Located in aggrading stands in the temperate zone, they have provided a strong foundation for testing critical assumptions in terrestrial biosphere models that are being used to project future interactions between forest productivity and the atmosphere, despite the limited inference space of these experiments with regards to the range of global ecosystems. Now, a new generation of FACE experiments in mature forests in different biomes and over a wide range of climate space and biodiversity will significantly expand the inference space. These new experiments are: EucFACE in a mature Eucalyptus stand on highly weathered soil in subtropical Australia; AmazonFACE in a highly diverse, primary rainforest in Brazil; BIFoR‐FACE in a 150‐yr‐old deciduous woodland stand in central England; and SwedFACE proposed in a hemiboreal, Pinus sylvestris stand in Sweden. We now have a unique opportunity to initiate a model–data interaction as an integral part of experimental design and to address a set of cross‐site science questions on topics including responses of mature forests; interactions with temperature, water stress, and phosphorus limitation; and the influence of biodiversity.

Electrocatalysis provides a powerful means to selectively transform molecules, but a serious impediment in making rapid progress is the lack of a molecular-based understanding of the reactive mechanisms or intermediates at the electrode–electrolyte interface (EEI). Recent experimental techniques have been developed for operando identification of reaction intermediates using surface infrared (IR) and Raman spectroscopy. However, large noises in the experimental spectrum pose great challenges in resolving the atomistic structures of reactive intermediates. To provide an interpretation of these experimental studies and target for additional studies, we report the results from quantum mechanics molecular dynamics (QM-MD) with explicit consideration of solvent, electrode–electrolyte interface, and applied potential at 298 K, which conceptually resemble the operando experimental condition, leading to a prototype of operando QM-MD (o-QM-MD). With o-QM-MD, we characterize 22 possible reactive intermediates in carbon dioxide reduction reactions (CO₂RRs). Furthermore, we report the vibrational density of states (v-DoSs) of these intermediates from two-phase thermodynamic (2PT) analysis. Accordingly, we identify important intermediates such as chemisorbed CO₂ (b-CO₂), *HOC-COH, *C-CH, and *C-COH in our o-QM-MD likely to explain the experimental spectrum. Indeed,weassign the experimental peak at 1,191 cm−1 to the mode of C-O stretch in *HOC-COH predicted at 1,189 cm−1 and the experimental peak at 1,584 cm−1 to the mode of C-C stretch in *C-COD predicted at 1,581 cm−1. Interestingly, we find that surface ketene (*C=C=O), arising from *HOC-COH dehydration, also shows signals at around 1,584 cm−1, which indicates a nonelectrochemical pathway of hydrocarbon formation at low overpotential and high pH conditions.

Reassimilation of internal CO2 via woody tissue photosynthesis has a substantial effect on tree carbon income and wood production. However, little is known about its role in xylem vulnerability to cavitation and its implications in drought-driven tree mortality. Young trees of Populus nigra were subjected to light exclusion at the branch and stem levels. After 40 d, measurements of xylem water potential, diameter variation and acoustic emission (AE) were performed in detached branches to obtain acoustic vulnerability curves to cavitation following bench-top dehydration. Acoustic vulnerability curves and derived AE50 values (i.e. water potential at which 50% of cavitation-related acoustic emissions occur) differed significantly between light-excluded and control branches (AE50,light-excluded = −1.00 − 0.13 MPa; AE50,control = −1.45 − 0.09 MPa; P = 0.007) denoting higher vulnerability to cavitation in light-excluded trees. Woodytissue photosynthesis represents an alternative and immediate source of nonstructural carbohydrates (NSC) that confers lower xylem vulnerability to cavitation via sugar-mediated mechanisms. Embolism repair and xylem structural changes could not explain this observation as the amount of cumulative AE and basic wood density did not differ between treatments. We suggest that woody tissue assimilates might play a role in the synthesis of xylem surfactants for nanobubble stabilization under tension.

BACKGROUND: In contrast to C₃ photosynthesis, the response of C₄ photosynthesis to water stress has been less-well studied in spite of the significant contribution of C₄ plants to the global carbon budget and food security. The key feature of C₄ photosynthesis is the operation of a CO₂-concentrating mechanism in the leaves, which serves to saturate photosynthesis and suppress photorespiration in normal air. This article reviews the current state of understanding about the response of C₄ photosynthesis to water stress, including the interaction with elevated CO₂ concentration. Major gaps in our knowledge in this area are identified and further required research is suggested. SCOPE: Evidence indicates that C₄ photosynthesis is highly sensitive to water stress. With declining leaf water status, CO₂ assimilation rate and stomatal conductance decrease rapidly and photosynthesis goes through three successive phases. The initial, mainly stomatal phase, may or may not be detected as a decline in assimilation rates depending on environmental conditions. This is because the CO₂-concentrating mechanism is capable of saturating C₄ photosynthesis under relatively low intercellular CO₂ concentrations. In addition, photorespired CO₂ is likely to be refixed before escaping the bundle sheath. This is followed by a mixed stomatal and non-stomatal phase and, finally, a mainly non-stomatal phase. The main non-stomatal factors include reduced activity of photosynthetic enzymes; inhibition of nitrate assimilation, induction of early senescence, and changes to the leaf anatomy and ultrastructure. Results from the literature about CO₂ enrichment indicate that when C₄ plants experience drought in their natural environment, elevated CO₂ concentration alleviates the effect of water stress on plant productivity indirectly via improved soil moisture and plant water status as a result of decreased stomatal conductance and reduced leaf transpiration. CONCLUSIONS: It is suggested that there is a limited capacity for photorespiration or the Mehler reaction to act as significant alternative electron sinks under water stress in C₄ photosynthesis. This may explain why C₄ photosynthesis is equally or even more sensitive to water stress than its C₃ counterpart in spite of the greater capacity and water use efficiency of the C₄ photosynthetic pathway.

In this research, the process of drying thyme with Infrared- assisted Refractance Window (IR-RW) method was investigated as a new technology. The effect of water temperature (WT) and weight of samples (SW) on kinetics, energy, thermodynamic properties, qualitative characteristics, bioactive and essential oil were determined and optimized. Based on the response surface method (RSM-CCD), WT (70-90 °C) and SW (60-120 g) to achieve the best drying time, energy consumption (SEC), color (ΔE), bioactive properties and essential oil efficiency (EO) were optimized. The results showed that Midilli’s model evaluates the stages of drying of the thin layer of thyme more appropriately than other models. Also, the effective diffusivity (D eff ) and Activation Energy (Ea), enthalpy (ΔH), entropy (ΔS) and Gibbs free energy (ΔG) were obtained between 8.67×10 -9 - 3.02×10 -8 m 2 /s, 20.71- 31.17 kJ/mol, 17.69-28.31 kJ/mol, -0.1490- -0.118 kJ/mol K and 67.69-73.04 kJ/mol, respectively. Increasing the WT raises the DR, brightness, AA, D eff and ΔH and decreases the drying time, SEC, ΔH, ΔG, CO 2 , Chroma, a*, b* and ΔE. The highest value of total phenol content (TPC), rehydration ratio (RR), EO was recorded at the WT of 80 °C and the SW was 90 g. The optimal values of the process variables are 85.02 °C for water temperature (WT) and 86.10 g for sample weight (SW). In addition to these values, the optimal values for drying time, SEC, ΔE, AA, TPC, TFC and OE were 91.003 minutes, 8.37 kWh/kg, 1.42, 71.68%, 37.93 mg GAE/ 100 g d.m, 35.11 mg QE/100 g d.m and 2.04%, respectively, at the desirability value of 0.807. Thus, these findings provide valuable insights for producers regarding the drying characteristics and properties of thyme.

Carbon capture and utilization are promising for addressing climate change, reducing CO₂ emissions and converting captured CO₂ into valuable chemicals. In this study, we explored Ti-Zr, Ti-Ce, and Zr-Ce oxides as CO₂ adsorbents and reaction accelerators for ethylene urea (EU) synthesis, aiming to develop a cost-effective CO₂ capture and transformation method. Binary metal oxides (TiₓZr₍₁₋ₓ₎O₂, TiₓCe₍₁₋ₓ₎O₂, and ZrₓCe₍₁₋ₓ₎O₂,) were synthesized via sol–gel and solvothermal methods, with X-ray diffraction revealing amorphous TiₓZr₍₁₋ₓ₎O₂, distinct TiO₂ and CeO₂ peaks for TiₓCe₍₁₋ₓ₎O₂, and intermediate crystallinity for ZrₓCe₍₁₋ₓ₎O₂. BET analysis indicated that TiₓZr₍₁₋ₓ₎O₂ had the highest surface area (~ 150 m2/g), which contributed to its high CO₂ adsorption (0.85 mmol/g) at 30 °C and 100 kPa pressure, almost double that of TiO₂ (0.42 mmol/g). CO₂ adsorption followed the Langmuir and Freundlich models (R2 > 0.98). Upon heating the CO₂-loaded oxides at 160 ℃ for 24 h, CeO₂ and ZrO₂ enhanced EU production, with CeO₂ showing superior selectivity. The reaction mechanism involved CO₂ desorption and dehydration. Ti₀.₃Zr₀.₇O₂ yielded 12.2 × 10⁻4 mmol/m2 EU, owing to its high CO₂ adsorption and higher zirconium content. Conversely, TiₓCe₍₁₋ₓ₎O₂ produced less EU (6.99 × 10⁻4 mmol/m2) due to lower CO₂ availability. These findings highlight TiₓZr₍₁₋ₓ₎O₂, especially Ti₀.₃Zr₀.₇O₂, as a promising catalyst for CO₂ utilization and EU synthesis.

Poly(ethylene oxide) (PEO)-based copolymers are at the forefront of advanced membrane materials for selective CO2 separation. In this work, free-standing composite membranes were prepared by blending imidazolium-based ionic liquids (ILs) having different structural characteristics with a PEO-based copolymer previously developed by our group, targeting CO2 permeability improvement and effective CO2/gas separation. The effect of IL loading (30 and 40 wt%), alkyl chain length of the imidazolium cation (ethyl- and hexyl- chain) and the nature of the anion (TFSI-, C(CN)3-) on physicochemical and gas transport properties were studied. Among all composite membranes, PEO-based copolymer with 40 wt% IL3-[HMIM][TFSI] containing the longer alkyl chain of the cation and TFSI- as the anion exhibited the highest CO2 permeability of 46.1 Barrer and ideal CO2/H2 and CO2/CH4 selectivities of 5.6 and 39.0, respectively, at 30 °C. In addition, almost all composite membranes surpassed the upper bound limit for CO2/H2 separation. The above membrane showed the highest water vapor permeability value of 50,000 Barrer under both wet and dry conditions and a corresponding H2O/CO2 ideal selectivity value of 1080; values that are comparable with those reported for other highly water-selective PEO-based polymers. These results suggest the potential application of this membrane in hydrogen purification and dehydration of CO2 gas streams.