Medium Temperature Conditions Research Articles

Three-stage, 70 Myr exhumation of HP/LT rocks on Margarita, Venezuela: Caribbean intra-forearc shear, Grenada Basin rifting, and continental obduction

The La Rinconada Terrane comprises the core of Margarita Island, Venezuela; it is a composite unit composed of rocks of both continental and oceanic affinity that were brought together and metamorphosed at high-pressure and low- to medium-temperature conditions in a collision zone along NW South America in Albian to Cenomanian time. Details of the ensuing three-stage exhumation path and concomitant eastward translation until Miocene oblique collision of Margarita with central and eastern Venezuela have remained the subject of discussion. In this paper we integrate the results of published age dating and the details of extensive Rb-Sr, K-Ar, 40Ar/39Ar and fission track dating that have been only superficially presented to date. Initial exhumation from high-pressure conditions into ductile mid-crustal levels occurred at 90-80 Ma, followed by essentially isobaric, isothermal conditions for ca. 30 Myr during which the La Rinconada Terrane was subjected to continual ductile penetrative shearing and recrystallization. Partial to total recrystallization with concomitant partial to total isotopic re-equilibration, especially of quartz-rich rocks, was widespread during this time interval. The youngest Rb-Sr, K-Ar and 40Ar/39Ar ages cluster at ca. 50 Ma. Zircon fission track ages of 50–40 Ma corroborate exhumation into brittle levels of the crust at this time. An apatite fission track age of 23 Ma indicates the attainment of shallow depths in Miocene time. This discontinuous history of exhumation fits tectonic models of the Caribbean well. As the Caribbean Plate led by the Antilles Arc entered the gap between the Americas, strongly dextral, transpressive subduction in the SE Caribbean drove shear deep within the forearc. The La Rinconada Terrane of Margarita was exhumed to mid-crustal depths in the Late Cretaceous and is suggested to have occupied high-angle forearc shear zones above the primary Benioff Plane. As the arc migrated past the Guajira promontory and became extensional due to roll-back of Proto-Caribbean oceanic crust north of the Falcón re-entrant of the South American margin, the La Rinconada Terrane formed the footwall of an Eocene lithospheric rift that opened by late Eocene into the Grenada (oceanic intra-arc) Basin, effecting exhumation into the brittle crust. The progressive obduction of the SE Caribbean Plate onto the South American continental margin during prolonged dextral oblique collision completed most of Margarita's exhumation history by middle Miocene time (17–12 Ma).

Ethanol Inhomogeneous Lean Combustion Under Different Ambient Temperatures and Pressures with Hydrogen Enrichment

ABSTRACT The effects of different ambient temperatures and pressures on the combustion of hydrogen-enriched liquid ethanol spray were studied in a constant-volume vessel, using experimental and numerical methods. The inhomogeneous combustion experiment was conducted under ultra-lean conditions at an overall equivalence ratio of 0.3 (33% spray ethanol/67% premixed hydrogen). The spray and flame images and combustion pressures were obtained. The spray simulation models used were the RANS k-ε turbulence model, KH-RT model, and wall film interaction model. The experimental results showed that the inhomogeneous combustion of the liquid ethanol spray can be divided into two stages: a rapid-burning and a slow-burning stage. The slow-burning stage was sensitive to changes in ambient temperature and pressure. Combustion duration decreased with elevated pressure and declined temperature. Under low pressure and medium temperature conditions, the flame reached its fastest propagation speed. The simulation results showed that the fuel concentration and concentration gradient around the ignition position are the key factors that affect inhomogeneous lean combustion. When the equivalence ratio was over 0.8 around the ignition position and the gradient of the equivalence ratio increased no less than 0.1/mm, the optimal combustion characteristics were achieved.

Ecological responses of epigaeic beetle composition to a volcanic eruption across temperate mountains featuring a forest‐steppe transition

Abstract Monitoring changes in species composition near active volcanoes is important to identify environmental factors that maintain biological diversity after major disturbances. We investigated the taxonomic composition of epigaeic beetles' assemblages in five mountains in north‐western Patagonia (Argentina) in the aftermath of the 2011 Puyehue Cordón‐Caulle Volcanic Complex eruption. The associations of beetle composition with the thermal environment, vegetation structure and soil characteristics were analysed using 10 m × 10 m plots with nine pitfall traps each, established 100 m apart in altitude on each mountain in 2005, 2006 (pre‐eruption) and 2012, 2015 and 2016 (post‐eruption). We found significant differences in beetle composition between forests and high‐Andean steppes before and after the eruption. The beetle composition of forests and high‐Andean steppes differed due to higher plant cover and lower pH and herb richness in forests. Six months after the eruption, the herbs almost disappeared and forests showed high ash accumulation and lower temperature than the high‐Andean steppes. In the medium term, plant cover, temperature and soil conditions—but not ash accumulation—remained as important correlates of beetle composition. Before the eruption, forest assemblages showed higher beetle diversity and Leiodidae indicator species, but Curculionidae predominated post‐eruption. Tenebrionidae and Carabidae were high Andean steppes indicators. Post‐eruption, the beetle composition in high‐Andean steppes did not change significantly except for an increase in Tenebrionidae indicator species. We concluded that the conservation of landscape diversity and environmental gradients maintaining the differentiation between ecoregions is essential to protect epigaeic beetle composition and for species survival after volcanic disturbances.

Versatile closed-cell SiC/C foam for microwave absorption under medium temperature, icing and mechanical conditions

Microwave-absorbing materials (MAMs) for applications such as aircraft protective layers and ship side panels often need to take into account the actual working conditions. Conventional MAMs are often difficult to take into account special functional requirements such as mechanics, high temperature, de-icing, etc. Therefore, there is an urgent need to develop MAMs with harsh environmental adaptability and multifunctional requirements.Here, we utilize SiO2 microspheres and phenolic resin to prepare precursor foams, and through calcination, we have prepared closed-cell SiC/C foam composites with both microwave absorption properties, mechanical properties and thermal properties. The effective absorption bandwidth (EAB) of the samples is up to 6.9 GHz at a thickness of 7.3 mm, which can satisfy the perfect coverage of the C-band, and can be further broadened by structural design. The samples can satisfy the full coverage of the X-band at 200 °C. The samples have loaded properties, and the maximum compressive strength of the samples is up to 10.5 mm. The samples are loaded with a maximum compression strength of 8 MPa, support repeated medium-temperature heating, and maintain a compression performance of 5.7 MPa after heating. The samples have good thermal conductivity and Joule thermal properties, and the surface temperature can be rapidly increased under the condition of applying a heat source or applying a low pressure to cope with the cold and humid working conditions. The composites in this paper are simple to prepare and have the potential for mass production.

Early Paleozoic ductile deformation of the South China Block: the polyphase shear zones in the eastern Jiangnan belt

Three parallel east–west-trending shear zones are components of the polyphase shear zones in the eastern Jiangnan belt. The meso- and microstructural characteristics and the estimates of deformation temperatures, vorticities and geochronology of these shear zones provide significant information regarding the tectonic evolution of the South China Block (SCB) during the early Paleozoic. Most shear sense indicators (e.g. asymmetric folds, S-C fabrics and rotating porphyroclasts) reveal that the kinematics were characterized by east–west dextral shear. Finite strain measurements indicate an oblate strain ellipsoid shape with S-type and SL-type tectonites. The rotated rigid porphyroclasts and Mohr circle methods yield vorticity ( Wk ) values of 0.58–0.80 and 0.66–0.89, respectively, indicating that the flow was generally shear-dominated with almost equal proportions of simple and pure shear. Both mineral deformation thermometers and quartz c -axis fabrics indicate that the deformation occurred at medium temperature conditions of 400–550°C. Combined with our new age and regional geological data, the east–west-trending shear zones might represent an increment of deformation during the last period of the early Paleozoic orogeny in the SCB.

High yield of heat-resistant spores of Bacillus megaterium in bioreactors

Microbial inoculants have been proposed as a sustainable and cost-effective alternative to conventional agricultural practices. However, the effectiveness of these bio-based products can be negatively impacted by reduced cell viability during product development, storage, and commercialization. To address these limitations, it is critical to identify and optimize the cultivation conditions that can lead to the production of highly resistant spores for use as inoculants. In this study, optimal cultivation conditions for obtaining Bacillus megaterium B119 spores in bioreactors were reached, with increases in the sporulation efficiency and heat resistance. The best nutrient medium and optimal temperature and initial pH conditions were obtained on shake flask experiments and subsequently validated in two bench-scale bioreactor models (stirred and aerated tank and the bubble column). The optimized temperature and initial pH were found to be 37 °C and 5.6. The highest concentration of heat-resistant Bacillus spores of 1.31·1012 CFU/mL was obtained in the bubble column bioreactor with a sporulation efficiency of 100.0%, a heat resistance of 78.4%, and an energetic efficiency on spores production of 4.83·1010 CFU/J. The production of highly resistant spores can significantly improve the survival rate of microorganisms during inoculant production and application, thereby enhancing their effectiveness in the field.

A Framework for Algae Modeling in Regulatory Risk Assessment.

The use of toxicokinetic-toxicodynamic (TKTD) modeling in regulatory risk assessment of plant protection products is increasingly popular, especially since the 2018 European Food Safety Authority (EFSA) opinion on TKTD modeling announced that several established models are ready for use in risk assessment. With careful adherence to the guidelines laid out by EFSA, we present a stepwise approach to validation and use of the Simple Algae Model Extended (SAM-X) for regulatory submission in Tier 2C. We demonstrate how the use of moving time windows across time-variable exposure profiles can generate thousands of virtual laboratory mimic simulations that seamlessly predict the effects of time-variable exposures across a full exposure profile while maintaining the laboratory conditions of the standard Organisation for Economic Co-operation and Development (OECD) growth inhibition test. Thus, every virtual laboratory test has a duration of 72 h, with OECD medium and constant light and temperature conditions. The only deviation from the standard test setup is the replacement of constant exposure conditions for time-variable concentrations. The present study demonstrates that for simulation of 72-h toxicity tests, the nutrient dynamics in the SAM-X model are not required, and we propose the alternative use of a simplified model version. For risk assessment, in accordance with the EFSA guidelines we use a median exposure profile of 10 as a threshold, meaning that if a time window within the exposure profile causes 50% growth inhibition when magnified by a factor of 10, the threshold will have been exceeded. We present a simplified example for chlorotoluron and isoproturon. The present case study brings to life our proposed framework for TKTD modeling of algae to establish whether a given exposure can be considered to be of low risk. Environ Toxicol Chem 2023;42:1823-1838. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Removal of oxytetracycline from wastewater by biochar modified with biosynthesized iron oxide nanoparticles and carbon nanotubes: Modification performance and adsorption mechanism

The pollution problem of oxytetracycline (OTC) from wastewater becomes more serious, so an efficient, economical, and green adsorption material is urgently explored. In this study, the multilayer porous biochar (OBC) was prepared by coupling carbon nanotubes with iron oxide nanoparticles synthesized by Aquabacterium sp. XL4 to modify corncobs under medium temperature (600 °C) conditions. The adsorption capacity of OBC could reach 72.59 mg g−1 after preparation and operation parameters were optimized. In addition, various adsorption models suggested that OTC removal resulted from the combined effect of chemisorption, multilayer interaction, and disordered diffusion. Meanwhile, the OBC was fully characterized and exhibited a large specific surface area (237.51 m2 g−1), abundant functional groups, stable crystal structure, high graphitization, and mild magnetic properties (0.8 emu g−1). The OTC removal mechanisms mainly included electrostatic interactions, ligand exchange, π-π bonding reactions, hydrogen bonds, and complexation. pH and coexistence substance experiments revealed that the OBC possesses a wide pH adaptation range and excellent anti-interference ability. Finally, the safety and reusability of OBC were confirmed by repeated experiments. In summary, OBC as a biosynthetic material shows considerable potential for application in the field of purifying new pollution from wastewater.

The ephemeral fumarolic mineralization of the 2021 Tajogaite volcanic eruption (La Palma, Canary Islands, Spain)

The present work aims to characterize the ephemeral mineral assemblage related to the fumarolic fields of the Tajogaite volcano, formed in 2021 in La Palma Island (Canary Islands, Spain). A set of 73 samples was obtained after two sampling campaigns in different fumarole sectors of the studied area. Mineralization related to these fumaroles formed efflorescent patches located at variable distance from the main volcanic craters. Distal patches are predominantly whitish, while in the vicinities they typically show yellowish to orange colours. Field observations also revealed that fumaroles usually occur in elevated topographic areas as well as over fractured and porous volcanic pyroclastic materials. The mineralogical and textural characterisation of the Tajogaite fumaroles unfolds a complex mineral assemblage, comprising cryptocrystalline phases related to low (< 200 °C) and medium temperature (200–400 °C) conditions. In Tajogaite, we propose a classification of three different fumarolic mineralization types: (1) fluorides and chlorides located in proximal fumarolic areas (~ 300–180 °C); (2) native sulphur associated with gypsum, mascagnite and salammoniac (~ 120–100 °C) and (3) sulphates and alkaline carbonates typically occurred in distal fumarolic areas (< 100 °C). Finally, we present a schematic model of the formation of Tajogaite fumarolic mineralization and their compositional evolution developed during the cooling of the volcanic system.

Thermodynamic simulation and experimental investigation of manganese oxide (MnOx) for integrated CO2 capture and conversion via chemical looping route

Due to its high energy conversion efficiency, low economic cost and collaborative pollution control, chemical looping is emerging as a promising technology to deal with CO2 emissions in energy and environmental fields. Based on the dual property of being carbonated and oxidized of MnO, the integrated CO2 capture and conversion performance of manganese oxide is analyzed via chemical looping CH4-O2-CO2 route. Thermodynamic calculation and process simulation indicate the equilibrium reduced solid is MnO instead of metallic Mn, which is consistent with material characterization. The gaseous oxygen released by MnO2 is the prerequisite for its reactivity from thermodynamic analysis and is the effective step for MnO2-CH4 reforming experiments. The CH4 reforming performance of Mn2O3 is limited from thermodynamic hierarchy and the lattice oxygen capacity of Mn3O4 affects its reactivity with CH4. Mn2O3 obtains the best partial oxidation reforming selectivity under higher operating temperature. The lattice oxygen is replenished with an obtained mole ratio of MnO2:Mn2O3 as 0.12:0.03 through air oxidation under medium temperature conditions. The weight increment at CO2 atmosphere indicates the 41.6 mol.% CO2 capture ability of MnO. The CH4-O2-CO2 cycle experiment proves the achievement in realizing the integrated CO2 capture and utilization with one material via chemical looping route.

A predictive model for ammonium removal in polishing ponds operated in sequential bath mode.

The magnitude of pH changes in polishing ponds can be predicted by simple stoichiometric rules if the extent of processes affecting this parameter is known. Thus, the objective of this article was to develop a model that predicts pH variation and ammonia desorption in polishing ponds in sequential batches, depending on the rates of processes that affect pH in ponds and to evaluate the influence of temperature and depth on these processes. As the temperature conditions change during the year, for model validation, tests were carried out under two medium temperature conditions (hot period and cold period) and four lakes with depths between 0.2 and 1.0 m. The proposed model is validated by the good correspondence between the simulated and experimentally obtained values for the two temperature conditions and for both periods. For the hot period, the model excelled, presenting a high linear correlation, always with R 2 above 0.90 for all ponds. For the cold period, the lowest R 2 obtained was 0.74 for the four lakes. Thus, the proposed model is suitable to describe the pH variation and ammonia desorption in polishing ponds in sequential batches, at all analyzed depths and under both temperature conditions.

Corrigendum to “Coupled heat transfer analysis of internal and film cooling of turbine blade under medium temperature conditions” [Appl. Therm. Eng. 214 (2022) 118792

Corrigendum to “Coupled heat transfer analysis of internal and film cooling of turbine blade under medium temperature conditions” [Appl. Therm. Eng. 214 (2022) 118792

Coupled heat transfer analysis of internal and film cooling of turbine blade under medium temperature conditions

• The coupled heat transfer of the internal cooling and film cooling are studied. • The effect of the heat conduction of solid regions on the heat transfer is checked. • The film hole enhances the flow and heat transfer of the internal channel. • The ribs increase the overall cooling effectiveness near the downstream of film hole. • The coupled heat transfer analysis contributed to find the fine design of blade. Increasing turbine inlet gas temperature is a main approach to meet the demands for high efficiency and thrust of advanced gas turbine engines. Both of internal and film cooling are often used at the same time for the turbine blade’s cooling to enhance the overall cooling performance and ensure the blade temperature below to the heat resistance temperature of blade material. Most of open studies focused on the individual cooling effect of either internal cooling or film cooling under normal temperature conditions. However, the actual working conditions of blade cooling is that internal cooling and film cooling affect each other because of the coolant flow through film hole and the heat conduction inside the blade solid regions (including the internal disturbing elements). In addition, the temperature difference between turbine inlet gas and coolant is much high. It is found that there are few studies on the coupled heat transfer characteristics of turbine blade cooling. To establish a numerical method for coupled heat transfer analysis of the turbine blade cooling, the coupled heat transfer in two perpendicular channels which are connected by a dividing wall and a film hole through the dividing wall is numerically investigated by simultaneously solving the air flow and convective heat transfer equations in the two passages. The heat conduction through the dividing wall (including the ribs equipped in the internal channel) and the flow through the film hole are also taken into consideration. The interaction between internal and film cooling can thus be explored. The mainstream inlet temperature is set to be 709 K to consider a medium temperature condition of turbine blade, and Reynolds number is 1.08 × 10 5 . The large-eddy simulation (LES) and SST κ-ω are employed to verify the applicability of turbulence models for the simultaneous simulation of internal and film cooling by comparing the numerical consequence with experiment from the published literature. It is indicated that LES can capture the fine structure of the flow field and has high accuracy in predicting the cooling effect. It is discovered that the heat conduction through the dividing wall of the two channels increases both of the internal convective cooling and the film cooling of the mainstream channel in comparison to the adiabatic cooling effect without considering the heat conduction inside the solid regions. In addition, the outflow through the film hole improves Nusselt number of internal channel, and the ribs bring about a slight increase of overall cooling effectiveness near the behind zone of the film hole, but decrease in the downstream a little far from the film hole. Besides, adjusting the blowing ratio could achieve higher blade cooling performance. It is suggested that we should not stay in the stage of studying internal or film cooling separately, but carry out more coupled heat transfer analysis of turbine blade cooling to find the appropriate geometric parameter/configuration of internal and film cooling for the fine design of gas turbine blade cooling, especially today when large-scale numerical calculation has become a reality.

Evaluation of the Rheological Properties of Virgin and Aged Asphalt Blends.

To evaluate the effects of the source and admixture of aged asphalt on the rheological properties of reclaimed asphalt binders, the relative viscosity (Δη), relative rutting factor (ΔG*/sinδ), and relative fatigue factor (ΔG*sinδ) were selected as evaluation indicators based on the Strategic Highway Research Program (SHRP) tests to characterize the rheological properties of a reclaimed asphalt binder under medium- and high-temperature conditions. The results of the study showed that the viscosity, rutting factor, and fatigue factor of the reclaimed asphalt binder increased with the addition of aged asphalt; however, the effect of the source and admixture of aged asphalt could not be assessed. The relative viscosity, relative rutting factor, and relative fatigue factor are sensitive to the source, admixture, temperature, and aging conditions, which shows the superiority of these indicators. Moreover, the relative viscosity and relative rutting factor decreased linearly with increasing temperature under high-temperature conditions, while the relative fatigue factor increased linearly with increasing temperature under medium-temperature conditions. In addition, the linear trends of the three indicators were independent of the source and admixture of aged asphalt. These results indicate that the evaluation method used in this study can be used to assess the effects of virgin asphalt and aged asphalt on the rheological properties of reclaimed asphalt binders, and has the potential for application. The viscosity of recycled asphalt increases, and the rutting factor and fatigue factor both increase. The high-temperature stability of reclaimed asphalt is improved, and the fatigue crack resistance is weakened.

Enhanced anaerobic digestion under medium temperature conditions: Augmentation effect of magnetic field and composites formed by titanium dioxide on the foamed nickel

There is global interest in developing clean energy, especially using green production strategies. Increasing the production of methane by anaerobic digestion (AD) is a green strategy that greatly benefits agricultural waste management. This study investigated the effects of combining a static magnetic field (SMF) with a novel porous conductive compound (TiO2-FNi) with bioaffinity as an additive in the anaerobic digestion and methanation of corn stover. Total experimental methane production with an optimized TiO2-FNi concentration (2.82 g L−1) in an 11.4 mT SMF was 44.71% greater than the control. Analysis of the composition of the microbial community showed the greatest relative abundance of the electroactive microorganisms Bacteroidota and Sytrophomonas spp. (phylum Firmicutes), 52.06%, in TiO2-FNi colonies. These microorganisms increase electron exchange through direct interspecies electron transfer with methanogens to increase methane yield. We propose a possible mechanism for the increased methane production due to the TiO2-FNi –SMF combination, which promotes microbial growth and reproduction and increases direct interspecies electron transfer (DIET) between microorganisms. Recovery of the TiO2-FNi composite reached 99.29%, which indicates great potential for recycling the material. The energy conversion efficiency of AD using the TiO2-FNi –SMF combination was 43.68%, which was 13.20% greater than the control.

Evolution and comprehensive evaluation of viscoelastic characteristics of road asphalt in medium temperature region

PurposeIn order to determine the range of medium temperature zone of road asphalt, it is hoped that the evolution of viscoelastic characteristics of road asphalt under medium temperature state can be deeply explored.Design/methodology/approachIn this paper, the needle penetration test and temperature scanning test were designed for 90# and 70# bitumen as test materials, and the boundary of medium temperature zone of 90# and 70# bitumen was accurately determined by data analysis method. A mathematical model was established based on principal component analysis, and a comprehensive evaluation index was proposed to evaluate the evolution of temperature viscoelastic characteristics of road asphalt by means of standardization and rotational dimensionality reduction.FindingsThe test results show that the medium temperature zone of 90# asphalt is [−5 ± 1°C, 38 ± 1°C], and the medium temperature zone of 70# asphalt is [0 ± 1°C, 51 ± 1°C]. According to the viscoelastic response of road asphalt in the medium temperature zone, the medium temperature zone can be divided into three evolution stages: weak viscoelastic stage, viscoelastic equilibrium stage, strong viscoelastic weak stage. Analysis based on the intrinsic viscosity fillip target describing the various intrinsic viscoelastic index represents the viscoelastic properties of bitumen from different angles, and limitations inherent stick fillip for target put forward the integrated the inherent stick fillip mark information, as well as targeted and accurate evaluation of road asphalt temperature comprehensive evaluation indexes in the evolution of the viscoelastic properties of IM-T. Finally, the temperature data of asphalt pavement in several representative regions of China are compared with the determined medium temperature region, and it is proved that the research on the evolution of viscoelastic characteristics of asphalt pavement under the medium temperature condition has important practical significance.Originality/valueThe boundary of medium temperature zone of 90# and 70# base asphalt was determined, and the viscoelastic characteristic evolution of road asphalt under medium temperature state was studied deeply. Aiming at the limitation of intrinsic viscoelastic index, a comprehensive evaluation index IM-T which not only integrates the information of intrinsic viscoelastic index but also can accurately evaluate the evolution of temperature viscoelastic characteristics in road asphalt is proposed.

Deformation, thermochronology and tectonic significance of the crustal-scale Cubatão Shear Zone, Ribeira Belt, Brazil

Crustal-scale shear zones are key structures in orogenic belts linked to the assembly of West Gondwana. The Cubatão Shear Zone (CSZ) represents a significant segment of a crustal-scale transcurrent shear zone system that cuts Paleoproterozoic to Neoproterozoic units in the Ribeira Belt (SE Brazil). Despite its tectonic importance, the relationship between transcurrent deformation and orogenesis is still controversial. This work aims to understand this relationship by integrating the transcurrent deformation history of the CSZ with regional orogenic processes through structural analyses, phase-equilibria modelling, and zircon and apatite U-Pb-REE analyses. The results indicate that the CSZ developed within a transpressional setting with a dominant subhorizontal stretching lineation at medium-temperature conditions of 460–520 °C and 4.5–9.5 kbar, consistent with quartz recrystallisation microstructures indicative of subgrain rotation recrystallisation. Igneous-type apatite from the mylonites of the CSZ record ages of ca. 610–570 Ma, which are interpreted as reset ages due to ductile deformation at medium-temperature conditions. Zircon U-Pb geochronology indicates that mylonites are sourced from the Juquiá Granite and the Atuba Complex. The CSZ activity is coeval with the main period of activity of other ductile shear zones from the Ribeira Belt, as indicated by available geochronological data. This age interval coincides with the main period of other regional shear zones activity, voluminous granitic magmatism, regional metamorphism and convergence of the cratons surrounding the Ribeira Belt, indicating active participation of the transcurrent shear zones in the orogenic processes that built up West Gondwana.

Graphene oxide-doped stearate-intercalated layered double oxide nanocomposites as high-performance CO2 adsorbents

The nanocomposites of graphene oxide (GO)-doped stearate-intercalated layered double oxides (LDO) as a new type of CO2 adsorbents at medium temperatures (200–400 °C) are reported for the first time. The doping of GO could improve stability of the composite material. The CO2 adsorption uptake (0.52 mmol/g) of LDO-Stearate (LDO-SA) was significantly increased by intercalating the long carbon chain organic anion of stearate. The 6 wt% GO − LDO-SA (6GO − LDO-SA) nanocomposite possessed the largest CO2 adsorption uptake (0.83 mmol/g), which was much larger than that (0.35 mmol/g) of the conventional LDO adsorbent. Such a high performance of 6GO − LDO-SA was associated with its increase in surface area and basic site amount. The adsorption process of CO2 on the nanocomposite was dominated by the chemical adsorption, and the adsorbed CO2 was mainly stored in the form of carbonate. The regeneration efficiency of 6GO − LDO-SA was>88% after 10 adsorption and desorption recycling tests, which was much higher than that of LDO. Simultaneously, the 6GO − LDO-SA adsorbent exhibited a fast kinetics (0.863 mmol/(g·min)) under the medium-temperature conditions. We are sure that the new nanocomposite materials fabricated in the present study are promising in the applications of carbon dioxide capture.

Effect of exogenous K+ addition on the denitrification efficiency of high salinity wastewater treatment by anammox process at medium and low temperature: In-depth study

In this study, high-salinity wastewater was treated by the anaerobic ammonia oxidation (anammox) process at medium and low temperature. Under the dual stress of salinity and low temperature, the anammox process was strengthened by exogenous addition of K+. Fast start-up of the anammox reactor was performed in 90 days. MLSS and MLVSS was 8388 mg/L and 7511 mg/L, respectively. The MLSS/MLVSS ratio was as high as 0.90 after the successful start-up of the reactor. The effects of sludge particle characteristics and denitrification efficiency with respect to gradual salinity gradient domestication at medium temperature (30 °C) was done. 30 g/L salinity stress inhibited the denitrification efficiency of the reactor. With the increase of salinity, the content of soluble extracellular polymeric substance (EPS) gradually increased and there was a sharp increase at 20 g/L salinity. The total nitrogen (TN) removal load was 0.64 kg/(m3·d) at low temperature (15 °C) and salinity 20 g/L with TN removal efficiency 88.81%. Under low temperature conditions, biomass and nitrite significantly inhibit the denitrification efficiency. Also, PS/PN ratio increases by 0.39 and the sludge granularity becomes worse. Static batch and continuous flow tests were performed to explore the effect of exogenous addition of K+ on the denitrification performance under anammox resistance salinity in the short-term and long-term experiments. Under the salinity stress of 6 g/L, X (compared to anammox activity) can be increased by 35.76%. With the increase of K+ concentration under medium and low temperature and high salinity, the denitrification efficiency first increased and then decreased. 5 mmol/L K+ was the best promotion point under medium temperature (30 °C) and high salinity (30 g/L), the TN removal efficiency was 86.22%, which was 10.88% higher than that of 0 mmol/L K+ intervention. The nitrogen removal rate (NRR) was increased from 0.83 kg/(m3·d) to 0.95 kg/(m3·d) increased by 10.87%. Under the optimal promotion point, 10 mmol/L K+ for low temperature (15 °C) and high salinity (20 g/L) the TN removal efficiency was 92.60% increased by 3.94%. Inhibition phenomenon appeared in 20 mmol/L K+ under medium and low temperature conditions.

Full recycling of high-value resources from cabbage waste by multi-stage utilization

Cabbage waste (CW) was recycled for generating some potential high-value products by a multi-stage treatment technology. A novel multi-stage utilization process was successfully proposed which consisted of low-temperature extraction, medium-temperature thermolysis, and high-temperature activation. Plant extracts that contain fatty acids, alcohol, furan, and esters were first extracted from raw cabbage waste by ethanol at 70 °C. Pyrolytic oil was obtained by cabbage waste pyrolysis at different medium temperature conditions. The produced carbon residue was further activated at high temperature for environmental purification such as VOCs removal. The performance of this process was characterized by N2 isothermal adsorption, Fourier transform infrared spectrometer (FTIR), thermogravimetric analysis (TG) and gas chromatography–mass spectrometry (GC–MS). Experimental results showed that the optimum temperatures for extraction, pyrolysis, and activation were 70 °C, 520 °C and 700 °C, respectively. Phenolic-rich pyrolysis solution with 50% phenolic contents could be obtained with the potential application of botanical pesticide. The produced biochar had a BET surface area of as high as 891.12 m2/g. The yields of biochar, pyrolytic liquid, and pyrolytic gas were 43.86%, 17.47%, 38.67%, respectively, and the process energy efficiency was over 42.7%. Applicability and feasibility of this process were also discussed in the aspects of energy quality balance, economy, and environment. The proposed multi-stage thermal-chemical process could be used as a full recycling method for biomass waste.