Production Rate Research Articles

Loss characteristics and optimization method of a compressed air energy storage radial turbine with nozzle governing

During the operation of the compressed air energy storage (CAES) system, a discrepancy exists between the air storage pressure and the turbine inlet pressure. At the same time, to ensure that the turbine operates efficiently when the system load varies, the turbine needs to be regulated reasonably. In this paper, the influence of three nozzle governing (NG) parameters on turbine performance during the NG process is investigated: the inlet pressure of the NG region, the area of the NG region, and the base pressure. The flow characteristics and loss mechanisms under partial admission conditions and NG conditions are also analyzed. Furthermore, the NG process is optimized by using a transition section. The results show that the loss under the NG condition with low inlet pressure at the NG region is similar to the partial admission loss, both of which are mainly affected by the area of the NG region. In both working conditions, vortex structures appear at the stator outlet of the NG region. At the same time, the mixing of different airflows and the flow separation phenomenon within the rotor leads to a significant increase in entropy production rate. The transition section can attenuate the leakage and reduce the entropy production rate in the radial gap between the stator and rotor, increasing turbine efficiency by up to 1.1 % at maximum when using the transition section.

Water/oil interfacial photocatalysis of amphiphilic CdS/Bi2WO6 S-scheme heterojunctions for efficient production and spontaneous separation of H2O2 and value-added organics

The photocatalytic co-production of H2O2 and value-added organics in a suitable water/oil biphasic system offers an intriguing strategy to address the challenges encountered in a single liquid-phase solution, including the efficient separation of H2O2 and organic products as well as the mitigation of undesirable secondary reactions. For this, exploring amphiphilic photocatalysts with high performance is highly required. Herein, an amphiphilic CdS/Bi2WO6 S-scheme heterojunction photocatalyst is designedly synthesized through a two-step solvothermal process, aiming to achieve efficient interfacial photocatalytic reactions at the water/oil interface for simultaneous generation and selective separation of H2O2 and organic products. The CdS/Bi2WO6 heterojunction photocatalyst exhibits enhanced light absorption in UV-visible region, increased electron-hole separation efficiency, and powerful charge carriers with high redox abilities. Moreover, the formation of S-scheme heterojunction improves the catalyst stability by preventing CdS from photocorrosion. As a result, the production rate of H2O2 reaches up to 216.76mmolg-1 h-1, accompanied by the generation of organic products (benzaldehyde: 104.91mmolg-1 h-1, benzoic acid: 49.88mmolg-1 h-1, and benzyl benzoate: 38.01mmolg-1 h-1), in a water/benzyl-alcohol biphasic system under simulated sunlight irradiation. The photocatalytic mechanism is elucidated based on the results of comprehensive experiments and characterizations. This study highlights a rational construction of amphiphilic photocatalysts and their application in organic/water interfacial photocatalytic reactions.

Cu nanoparticles immobilized in mesopores generated in zeolite for high-performing CO2 hydrogenation to methanol

Copper nanoparticles (Cu NPs) are commonly used as catalyst active components in CO2 hydrogenation reactions. However, they often lose their catalytic activity due to sintering in most reaction environments. This study explores a solution for Cu-supported catalysts used for methanol production from CO2 hydrogenation by fixing Cu NPs in the mesopores generated in zeolite. Mesopores were generated in NaY zeolite by partially dealuminating its framework. High-resolution (scanning) transmission electron microscopy (HR(S)TEM) and CO adsorption measurements confirm that the synthesized mesoporous zeolite-supported Cu NPs are highly dispersed and fixed within the mesopores. In comparison with conventional microporous zeolite-supported Cu NPs (2 wt%), Cu NPs (2 wt%, average size of 2.2 nm) in mesoporous zeolite increased methanol production from ∼26 mmolgCu−1h−1 to approximately 56 mmolgCu−1h−1 at 250 °C. By further modifying the mesoporous zeolite with Zr (2 wt%), Cu NPs increased in size, and the methanol production rate increased approximately 2.2 folds to 125 mmolgCu−1h−1 under similar conditions due to zeolite electronic modification and the newly formed Zr-zeolite/Cu interface. However, the addition of Zr significantly increased the Cu NP size and moved part of them out of the mesopores, lowering their stability. In situ DRIFTS experiments reveal CO2 hydrogenation proceeds through the formate route via a direct formation of dominantly carbonate (*CO3), which hydrogenates to formate (*HCOO) and traces of methoxy (*H3CO), and subsequently methanol (CH3OH). This study reports the design of active and stable catalysts for CO2 hydrogenation to methanol by engineering Cu NPs in zeolite pores

Lower NO emission conditions of NH3–H2 mixtures under the oxygen-enriched premixed combustion mode

Compared with pure NH3 fuel, the lower NO emission conditions of NH3–H2 mixtures under the oxygen-enriched combustion mode have been identified quantitatively. Furthermore, the effects of the H2 addition on the NO productions of premixed oxygen-enriched NH3–H2 flames are studied numerically, while the major reactions responsible for the variation of total NO are identified. Results show that the H2 addition is eligible to reduce the NO emissions of the oxygen-enriched NH3 combustion if the laminar burning velocity is fixed to a larger value (>23 cm/s). The quantitative equations are obtained to determine the optimum oxygen-enriched conditions of the NH3–H2 mixture, aiming to achieve lower NO emission and similar or improved combustion stability compared to pure NH3 fuel by restricting the minimum and maximum O2 percentages for the NH3–H2 mixtures. Based on the rate of production (ROP) analysis, for the oxygen-enriched NH3–H2 combustion, R144 (HNO + H<=>H2+NO) is consistently the most significant NO production reaction, while R85 (NH + NO<=>N2O + H) and R91 (N + NO<=>O + N2) play significant roles in the NO consumption. When the laminar burning velocity (SL) is kept to a lower value, the increased total NO of the oxygen-enriched NH3 flames with the H2 addition is ascribed to more efficient suppressions on the NO consumption reactions of R85, R91 and R77 (NH2+NO<=>NNH + OH). In contrast, thanks to the extra impact of the higher O2 percentage on the H/O/OH radical pool at larger SL, the NO production reactions begin to suffer stronger suppressions of the H2 addition, resulting in the reduced total NO of NH3–H2 mixtures. Furthermore, R144 is identified as the key reaction influencing the variation trend of total NO at both lower and higher SL values.

Nano-encapsulation of essential amino acids: ruminal methane, carbon monoxide, hydrogen sulfide and fermentation

This study aimed to evaluate the effect of nano-encapsulation of four essential amino acids (AA), threonine, methionine, tryptophan, and lysine on in vitro ruminal total gas, methane, carbon monoxide, and hydrogen sulfide production as well as the rumen fermentation profile in cattle. The highest (P < 0.001) rate and asymptotic gas production after 48 h of incubation was observed in the diets that had threonine, followed by lysine, methionine, and tryptophan. Asymptotic methane gas production decreased in the following order: threonine > lysine > tryptophan > methionine (P < 0.0001) and the rate of production per hour followed the same trend (P = 0.0259). CH4 parameters showed that in 4 h, 24 h, and 48 h of incubation the lowest methane production was obtained in the diet with methionine (P < 0.05) and the highest one in diet supplemented with threonine. Methane fractions showed that methionine-containing diets resulted in more (P < 0.05) metabolizable energy versus methane, followed by tryptophan-containing, and then lysine-containing diets. Methionine-fortified diets seem to be the most eco-friendly among those studied regarding methane output. However, based on methane, CO, and H2S output as well as the rumen fermentation profile nano-encapsulated lysine is recommended for use in ruminant nutrition.

Analytical and descriptive study of the production behavior for pilot multi-stages hydraulic fracturing wells in southeast Iraq

The hydraulic fracturing technique is a widely used technique worldwide, making it interesting to study. This technique was applied for the first time in Iraq on a tight carbonate reservoir in the Halfaya oil field. In this field, the oil production rates, and flowing pressure were low during production periods reflecting a problem for the development plan designed to increase production using a hydraulic fracture technique. Initially, the hydraulic fracture well showed high oil-producing rates, but then, quickly experienced a high decline failing to keep a stable production rate. To address this problem, it is important to describe and analyze the behavior of pilot hydraulic fracturing wells during their production period, study the inflow performance relationship (IPR), and determine the optimum wellhead pressure above the bubble point pressure (Pb) to avoid loss of lifting energy. Furthermore, it identifies the allowable flow rate to keep stable production, investigates the effect of selecting internal tubing size, and reveals a future production procedure for hydraulic fracture wells. This study reveals that the transient inflow performance relationship observed in the production history of hydraulic fracture well in the tight carbonate reservoir and traditional inflow performance relationship concepts are not applicable. The optimum wellhead pressure for stability in production for Wells w-5 and w-55 is determined to be 750 and 580 psi with optimum rates of 800 and 450 Bbl/D, respectively. The results also showed that producing at a high flow rate may cause a depletion in the fracture potential storage without giving an opportunity for a reservoir to compensate for the produced fluid into fracturing potential storage. The internal tubing size has a passive effect on the hydraulic fracture well, as an increase in size causes an unstable flow zone. Lastly, future production procedures emphasize keeping wellhead pressures stable or increasing them if they drop. This can be accomplished by re-adjusting the choke size according to any changes observed.

Effect of cold beverages on whole-body heat exchange in young and older males during intermittent exercise in the heat.

To mitigate health risks associated with occupational heat stress, workers are advised to adhere to a work-rest regimen, and hydrate regularly. However, it remains unclear if beverage temperature influences whole-body heat exchange during work-rest cycles, and if responses differ in older workers who have a blunted heat loss capacity. Ten young (mean [SD]: 22 [3] years) and 10 older (60 [4] years) males performed four 15-min bouts of moderate-intensity cycling at a fixed rate of metabolic heat production (200 W·m-2), each interspersed by 15-min rest in dry heat (40°C, ~12% relative humidity). On separate days, participants consumed either ice-slurry (~0°C), standardized to provide a heat transfer capacity of 75 kJ·m-2, or an identical mass of warm fluid (37.5°C) before the first and third exercise bouts. Evaporative and dry heat exchange (direct calorimetry) and metabolic heat production (indirect calorimetry) were measured continuously to determine cumulative heat storage (summation of heat loss and heat gain) over the entire protocol. Rectal temperature was also measured continuously. Relative to warm fluid, ice-slurry ingestion reduced cumulative heat storage in young (69 [181] vs. 216 [94] kJ) and older males (90 [104] vs. 254 [140] kJ, main effect: p < 0.01), but was unaffected by age (p = 0.49). However, rectal temperature was unaffected by beverage temperature in both groups (all p ≥ 0.15). We show that cold fluid ingestion is an appropriate administrative control for both young and older males as it can mitigate increases in body heat content during moderate-intensity work-rest cycles in dry heat.

A tailored cytochrome P450 monooxygenase from Gordonia rubripertincta CWB2 for selective aliphatic monooxygenation.

Cytochrome P450 monooxygenases are recognized as versatile biocatalysts due to their broad reaction capabilities. One important reaction is the hydroxylation of non-activated C-H bonds. The subfamily CYP153A is known for terminal hydroxylation reactions, giving access to functionalized aliphatics. Whilst fatty derivatives may be converted by numerous enzyme classes, midchain aliphatics are seldomly accepted, a prime property of CYP153As. We report here on a new CYP153A member from the genome ofthe mesophilic actinobacterium Gordonia rubripertincta CWB2 as an efficient biocatalyst. The gene was overexpressed inEscherichia coli and fused with a surrogate electron transport system from Acinetobacter sp. OC4. This chimeric self-sufficient whole-cell system could perform hydroxylation and epoxidation reactions: conversions of C6-C14 alkanes, alkenes, alcohols and of cyclic compounds were observed, yielding production rates of, e.g., 2.69 mM h-1 for 1-hexanol and 4.97 mM h-1 for 1,2-epoxyhexane. Optimizing the linker compositions between the protein units led to significantly altered activity. Balancing linker length and flexibility with glycine-rich and helix-forming linker units increased 1-hexanol production activity to 350 % compared to the initial linker setup with entirely helical linkers. The study shows that strategic coupling of efficient electron supply and a selective enzyme enables previously challenging monooxygenation reactions of midchain aliphatics.

Synthesis of Doped g‐C3N4 Photonic Crystals for Enhanced Light‐Driven Hydrogen Production from Catalytic Water‐Splitting

Dopants are frequently used to improve graphitic carbon nitride (gCN) photoactivity. As a doping source, phosphomolybdic acid (PMA) can activate doping sites inside the gCN lattice, resulting in 2D Mo:P‐gCN porous material. However, the gradual loading of the PMA fraction has no systematic improvement in the Mo:P‐gCN photoactivity. For improving the optoelectronic properties of Mo:P‐gCN, its textural geometry is a controllable parameter that can provide enhanced photonic properties, achievable by shaping its morphology through a crystalline template structure, namely, photonic crystals (PCs). Herein, a doped PC material is made of Mo:P‐gCN and PCs and labeled as Mo:P‐gCN/PCs. The impact of PCs is highlighted in the structural, electronic, and optical performances of Mo:P‐gCN. A well‐defined 3D crystalline network is evidenced by microscopic measurements (scanning electron microscopy, AFM, focused ion beam). Mo:P‐gCN/PCs shows a hydrogen production rate (750 μmol g−1 h−1) one time higher than Mo:P‐gCN and 6 times higher than pure gCN. The synthesis strategy proposed in this work leads simultaneously to the Mo:P codoping effect provided by PMA and the slow photon effect due to the PC structure, offering a novel strategy to improve the gCN photoactivity by simultaneously applying polyoxometalates as modifiers and polystyrene opals as templates.

The Effect of Water Quality on the Performance Growth of Vannamei Shrimp (Litopenaeus vannamei) at the Center for Brackish Aquaculture Fisheries

Vaname shrimp is one of the leading commodities of the aquaculture sector, with high production rates influenced by the rapid growth period and relatively short maintenance time, high stocking density production system, has a high appetite for food and has good resistance to disease. This study aims to assess the effect of water quality on the growth of vaname shrimp (Litopenaeus vannamei) in ponds. Water quality measured includes temperature, salinity, dissolved oxygen (DO), and pH, all of which play an important role in the growth and health of shrimp. The methods used in this study included periodic measurements of water quality parameters in the morning and evening in four ponds (A5.1, A5.2, A6.1, and A6.2), as well as observations of Average Body Weight (ABW), Average Daily Growth (ADG), and Survival Rate (SR) of shrimp. The results showed that ponds A5.1, A5.2, and A6.1 showed an increase in SR and biomass values, while A6.2 experienced a decrease in SR and biomass values caused by the outbreak of White Feces Disease. This is influenced by temperature, salinity, and DO parameters that are not in the optimal range for shrimp growth. Fluctuations in water quality parameters can significantly affect shrimp metabolism and health. Therefore, good water quality management, including water change cycles and sterilisation, is essential to prevent health problems and improve the growth of vaname shrimp. This study emphasises the need for attention to water quality in vaname shrimp farming to achieve optimal results.

Stand age-related effects of mangrove on archaeal methanogenesis in sediments: Community assembly and co-occurrence patterns

Mangrove sediment is a key source of methane emissions; however, archaea community structure dynamics and methanogenesis activities during long-term mangrove restoration remain unclear. In this study, microcosm incubations revealed a substantial reduction in microbial-mediated methane production potential from mangrove sediments with increasing stand age; methane production rates decreased from 0.42 ng g−1 d−1 in 6-year-old stands to 0.23 ng g−1 d−1 in 64-year-old stands. High-throughput sequencing revealed a reduction in community diversity because of specific microorganism colonization and species loss, notably a decline in the relative abundance of Bathyarchaeia in sediments of 64-year-old stands. In addition, mangrove sediments, especially those in older stands (20- and 64-year-old), had more complex and stable co-occurrence microbial networks than mudflats. Furthermore, archaea community assembly in older stands was dominated by stochastic processes wherein dispersal limitation was prominent, and that in younger stands (6- and 12-year-old) was driven by deterministic processes. The proportion of dispersal limitation of Bathyarchaeia and traditional methanogens in sediment decreased with an increase in stand age. Quantitative polymerase chain reaction analysis confirmed a decrease in Bathyarchaeia (from 3.50 to 0.54 copies g−1) and mcrA gene (from 3.83 to 0.25 copies g−1) abundance in mangrove sediments with an increase in stand age. These findings demonstrate the critical role of Bathyarchaeia in methanogenesis; the decline in microbial interactions and abundance, and the reduced proportion of dispersal limitation of Bathyarchaeia and traditional methanogens collectively contributed to the mitigation of microbial-mediated methane production potential in older mangrove stands.

Antioxidant and Longevity-Related Properties of the Ethyl Acetate Fraction of Cnidium officinale Makino in Caenorhabditis elegans.

Reactive oxygen species (ROS) are produced from energy metabolism and may cause diseases or cell death. Antioxidation refers to the suppression of ROS production and is considered beneficial in preventing diseases. This study aimed to examine the antioxidative effects of Cnidium officinale Makino (COM) extracts and fractions using Caenorhabditis elegans as an experimental model. The COM ethanol extract was fractionated according to polarity. The results showed that the ethyl acetate fraction of COM showed powerful radical scavenging activities and increased the activities of superoxide dismutase (SOD) and catalase in C. elegans in a concentration-dependent manner. Moreover, the ethyl acetate fraction reduced the ROS production rate in C. elegans and increased the cell survival rate, suggesting oxidative and thermal stress resistance. In addition, the SOD-3::green fluorescent protein (GFP) expression level in the transformed cells of C. elegans (CF1553) increased, suggesting oxidative stress resistance. Similarly, the HSP-16.2::GFP expression level increased, suggesting thermal stress resistance. In conclusion, the ethyl acetate fraction of COM demonstrated the strongest antioxidative effects, indicating that it may help extend longevity.

Evaluating the efficacy of water alternating gas injection technique in the upper jurassic hydrocarbon reservoirs, considering saturation pressure

A tertiary method of enhanced oil recovery (EOR) based on the watergas alternating injection process (WG) is examined in this article based on the ratio between saturation pressure and reservoir pressure. A hydrodynamic simulation of the WAG process was carried out using TEMPEST MORE software (version 7,1). Many hydrocarbon fields worldwide are currently experiencing declining production rates. However, by utilizing advanced technologies like alternate injection of water and associated petroleum gas, the final oil recovery factor (RF) can be significantly increased. To ensure successful water injection experiments in real fields, it is crucial to consider the ratio of saturation and reservoir pressures during injection. Any negligence in this regard can lead to failure of the experiments aimed at enhancing oil recovery through WAG application. The research examines two variations of reservoir system models with certainty. In the initial model, the saturation pressure is lower than the reservoir pressure, signifying an under-saturated state of the reservoir system containing dissolved gas. Consequently, when accompanying petroleum gas is introduced, it mixes with oil at precise thermobaric conditions. According to the second model, the reservoir is saturated with gas at a saturation pressure equivalent to the formation pressure. A thorough assessment indicates that the success of water alternating gas injection (WAG) is heavily influenced by the initial state of the reservoir. In situations where the reservoir is already saturated with gas, implementing water-gas stimulation may be ineffective as gas breakthroughs may occur rapidly. However, implementing WAG in saturated reservoirs can lead to a 1 – 8% rise in overall oil production, observable within 3 – 4 years, depending on the timing after waterflooding. Simultaneously, in the case of reservoirs with a low saturation pressure, which exhibits an undersaturated reservoir system, the implementation of water alternating gas injection can be seen as a viable approach for enhancing oil recovery. WAG is a proven method that confidently increases oil recovery up to 10% in undersaturated reservoirs compared to conventional waterflooding.

Slab assignment to non-identical reheat furnaces running in parallel mode

This article analyses a slab assignment problem for non-identical reheat furnaces in the steelmaking industry. We tackle the problem of assigning slabs to different types of reheat furnaces, a walking beam and a pusher type furnace. Furthermore, we need to determine the feed-in as well as the residence time for each slab. The aim is to (i) reduce the energy consumption, (ii) increase the production rate and (iii) the heating quality of the slabs which depends on the assigned furnace and to what extent the slabs are overheated. Moreover, the subsequent production stage (Hot Rolling Mill), needs to be synchronized with the furnaces which is essential for a smooth production. We specify the problem as a mixed integer optimization formulation that is solved with iterative parameter adjustment. Rapid convergence leads to a novel two-phase solution method that yields furnace schedules that are optimal for the adjusted parameter values in reasonable time. The results show that our proposed method performs better than an industry benchmark by increasing the production rate and increasing the reheating quality. Furthermore, the new generic problem formulation allows using standard software and can be applied to identical or non-identical furnaces highlighting its broad applicability across steel-making companies.

Investigation of kinetic mechanisms of photocatalytic hydrogen generation from formic aside using metal-ceramic composites under visible-light irradiation

Processes of photocatalytic hydrogen generation from the formic acid water solution under vis-light irradiation with tantalum contained metal-ceramic silicon nitride-based composites were investigated depending on pH of the solution and hydrogen peroxide adding. These compounds were obtained by self-propagated high temperature (SHS) synthesis in the way of the ferrosilicoaluminum (FSA) and silicon-aluminum powders ignition in a nitrogen atmosphere with the tantalum addition. During the investigation it was found out that the reaction rate of the hydrogen production without hydrogen peroxide can be described within the Langmuir–Hinshelwood mechanism. There is the reaction mechanism changing simultaneously with a formic acid concentration increasing in the presence of H2O2. The most significant reaction rate of hydrogen production from HCOOH is observed with the Fe-contained composite synthesized from FSA in the solution system without H2O2 addition, the reaction turns of frequency (TOF) is 4.55 µmol/min.

Continuous flow synthesis of MOF UTSA-16(Zn), mixed-metal and magnetic composites for CO2 capture – toward scalable manufacture

UTSA-16(Zn) is a zinc and citrate-based metal-organic framework (MOF) which has shown highly promising performance for CO2 capture. However, the transition of this MOF to industrial application has been hindered as a scalable synthesis method has not yet been reported. Herein we report the first scalable continuous flow synthesis of UTSA-16(Zn), demonstrating a production rate of 173 g/h, which is a 77-fold increase compared to previously reported batch methods. Sustainability of the synthesis was maximised using low-cost non-toxic reagents and a low-energy flow reactor operating at atmospheric pressure. Chemical (reactant ratios, Zn/Mg mixed-metal) and process parameters (solvent ratio, flow rate, temperature) were optimised to continuously produce UTSA-16(Zn) which also demonstrated a high CO2 adsorption capacity up to 3.8 mmol/g and conversion yield of up to 66 %. Pristine MOFs are typically thermally insulating, thus thermal regeneration is challenging. To overcome this limitation, magnetic nanoparticles can be embedded within the MOF. This enables fast and energy efficient regeneration through magnetic induction heating. Here, citrate-coated Fe3O4 magnetic nanoparticles (MNP-CA) were successfully incorporated into the flow synthesis process of UTSA-16(Zn) to form UTSA-16(Zn)@MNP-CA magnetic framework composites (MFCs), representing the highest production rate reported of any MFC to date (152 g/h c.f. 13 g/h for MgFe2O4@UiO-66-NH2). UTSA-16(Zn)@MNP-CA MFCs demonstrate rapid heating under a magnetic field (26–150 °C in 60 s). The flow method developed herein is also widely applicable for scalable manufacture of other MOFs and MFCs, enabling their broader transition towards industrial applications.

Harnessing the Energy Potential and Value-Added Products from the Treatment of Sugarcane Vinasse: Maximizing Methane Production Through Co-Digestion with Sugarcane Molasses and Enhanced Organic Loading.

This study assessed the impact of organic loading rate (OLR) on methane (CH4) production in the anaerobic co-digestion (AcoD) of sugarcane vinasse and molasses (SVM) (1:1 ratio) within a thermophilic fluidized bed reactor (AFBR). The OLR ranged from 5 to 27.5kg COD.m-3.d-1, with a fixed hydraulic retention time (HRT) of 24h. Organic matter removal varied from 56 to 84%, peaking at an OLR of 5kg COD.m-3.d-1. Maximum CH4 yield (MY) (272.6 mL CH4.g-1CODrem) occurred at an OLR of 7.5kg COD.m-3.d-1, while the highest CH4 production rate (MPR) (4.0L CH4.L-1.d-1) and energy potential (E.P.) (250.5 kJ.d-1) were observed at an OLR of 20kg COD.m-3.d-1. The AFBR exhibited stability across all OLR. At 22.5kg COD.m-3.d-1, a decrease in MY indicated methanogenesis imbalance and inhibitory organic compound accumulation. OLR influenced microbial populations, with Firmicutes and Thermotogota constituting 43.9% at 7.5kg COD.m-3.d-1, and Firmicutes dominating (52.7%) at 27.5kg COD.m-3.d-1. Methanosarcina (38.9%) and hydrogenotrophic Methanothermobacter (37.6%) were the prevalent archaea at 7.5kg COD.m-3.d-1 and 27.5kg COD.m-3.d-1, respectively. Therefore, this study demonstrates that the organic loading rate significantly influences the efficiency of methane production and the stability of microbial communities during the anaerobic co-digestion of sugarcane vinasse and molasses, indicating that optimized conditions can maximize energy yield and maintain methanogenic balance.

Continuous augmentation of anaerobic digestion with electroactive microorganisms: Performance and stability

The performance and stability of a bioelectrochemical anaerobic digester (BeAD), continuously augmented with electroactive microorganisms (EAMs), were investigated. The BeAD showcased superior performance, sustaining the high COD removal efficiency and methane production rate of 76.5 % and 0.67 L/(L.d), respectively, in a stable state. Prominently, it exhibited remarkable resilience under hydraulic and organic shock loads, adeptly recuperating from disturbances up to 1000 % of its stable condition. This resilience of up to 300 % shock load was driven by increased levels of electron transport components such as quinones and riboflavins, which act as electron shuttles. However, after extreme shock exposures from 500 % to 1000 %, despite the spike in inhibitory by-products such as humic acids and ammonia, the upregulation of the mtr complex was pivotal in recovering and sustaining methane production. These insights emphasize the BeAD’s capability to bolster both performance and stability, thereby providing a potent strategy for practical application of bioelectrochemical systems.

Partial oxidation of Rh/Ru nanoparticles within carbon nanofibers for high-efficiency hydrazine oxidation-assisted hydrogen generation

Hydrazine oxidation reaction (HzOR), an alternative to oxygen evolution reaction, effectively mitigates hydrazine pollution while achieving energy-efficient hydrogen production. Herein, partially oxidized Ru/Rh nanoparticles embedded in carbon nanofibers (CNFs) are fabricated as a bifunctional electrocatalyst for hydrogen evolution reaction (HER) and HzOR. The presence of multiple components including metallic Ru and Rh and their oxides provides numerous electrochemically active sites and superior charge transfer properties, thus improving the electrocatalytic performance. Additionally, the confinement of the active components within CNFs further enhances structural stability. Consequently, the optimized electrocatalyst exhibits ultralow overpotentials of 16 mV at 10 mA cm−2 and 176 mV to reach an industry-level current density of 1 A cm−2 for HER, considerably outperforming the benchmark Pt/C catalyst. Furthermore, it shows an outstanding anodic HzOR activity, achieving a small potential of –0.019 V to generate 10 mAcm−2. A two-electrode overall hydrazine splitting (OHzS) cell prepared using the electrocatalyst operates at a compelling voltage that is 1.953 V lower than that of the overall water splitting (OWS) cell at 200 mA cm−2. Furthermore, the OHzS cell achieves a hydrogen production rate of 1.17 mmol h−1, which is 15-fold that of OWS. Additionally, Rh1Ru1Ox-CNFs-350 is used to construct a Zn-hydrazine battery with excellent performance. This study presents an effective system for achieving high-yielding green H2 production with low energy consumption while simultaneously addressing hydrazine pollution.

A multi-step calibration strategy for reliable parameter determination of salt rock mechanics constitutive models

The storage of renewable hydrogen in salt caverns requires fast injection and production rates to cope with the imbalance between energy production and consumption. This raises concerns about the mechanical stability of salt caverns under such operational conditions. The use of appropriate constitutive models for salt mechanics is an important step in investigating this issue, therefore many constitutive models with several parameters have been presented in the literature. However, a robust calibration strategy to reliably determine which model and parameter set represents the given rock, based on stress–strain data sets, remains an unsolved challenge. In this paper, for the first time in the community, we present a multi-step strategy to determine a single parameter set based on many deformation data sets for salt rocks. Towards this end, we first develop a comprehensive constitutive model able to capture all relevant nonlinear deformation physics of transient, reverse, and steady-state creep. The determination of the single set of representative material parameters is then achieved by framing the calibration process as an optimization problem, for which the global Particle Swarm Optimization algorithm is employed. To allow for dynamic data integration, a multi-step calibration strategy is developed for a situation where experiments are included one at a time, as they become available. Additionally, due to the existing mild heterogeneity in the experimental rock samples, our optimization strategy is made flexible to allow for this slight heterogeneity. The devised optimization strategy, based on the multi-physics comprehensive constitutive modeling framework, results in a single set of representative material properties of all the deformation data sets. As a rigorous mathematical analysis for the presented method and the lack of relevant experimental data sets, we consider a wide range of synthetic experimental data sets, inspired by the existing sparse relevant data in the literature. The results of our performance analyses show that the proposed calibration strategy is robust. Moreover, the results become increasingly more accurate as more data sets become available.