Solar Ring Mission: Building a Panorama of the Sun and Inner-heliosphere

Solar Ring (SOR) is a proposed space science mission to monitor and study the Sun and inner heliosphere from a full 360{\deg} perspective in the ecliptic plane. It will deploy three 120{\deg}-separated spacecraft on the 1-AU orbit. The first spacecraft, S1, locates 30{\deg} upstream of the Earth, the second, S2, 90{\deg} downstream, and the third, S3, completes the configuration. This design with necessary science instruments, e.g., the Doppler-velocity and vector magnetic field imager, wide-angle coronagraph, and in-situ instruments, will allow us to establish many unprecedented capabilities: (1) provide simultaneous Doppler-velocity observations of the whole solar surface to understand the deep interior, (2) provide vector magnetograms of the whole photosphere - the inner boundary of the solar atmosphere and heliosphere, (3) provide the information of the whole lifetime evolution of solar featured structures, and (4) provide the whole view of solar transients and space weather in the inner heliosphere. With these capabilities, Solar Ring mission aims to address outstanding questions about the origin of solar cycle, the origin of solar eruptions and the origin of extreme space weather events. The successful accomplishment of the mission will construct a panorama of the Sun and inner-heliosphere, and therefore advance our understanding of the star and the space environment that holds our life.Comment: 41 pages, 6 figures, 1 table, to be published in Advances in Space Researc

The dynamic evolution of multipoint interplanetary coronal mass ejections observed with BepiColombo, Tianwen-1, and MAVEN

We present two multipoint interplanetary coronal mass ejections (ICMEs) detected by the Tianwen-1 and Mars Atmosphere and Volatile Evolution spacecraft at Mars and the BepiColombo (0.56 au ∼0.67 au) upstream of Mars from 2021 December 5 to 31. This is the first time that BepiColombo is used as an upstream solar wind monitor ahead of Mars and that Tianwen-1 is used to investigate the magnetic field characteristics of ICMEs at Mars. The Heliospheric Upwind Extrapolation time model was used to connect the multiple in situ observations and the coronagraph observations from STEREO/SECCHI and SOHO/LASCO. The first fast coronal mass ejection event (∼761.2 km s−1), which erupted on December 4, impacted Mars centrally and grazed BepiColombo by its western flank. The ambient slow solar wind decelerated the west flank of the ICME, implying that the ICME event was significantly distorted by the solar wind structure. The second slow ICME event (∼390.7 km s−1) underwent an acceleration from its eruption to a distance within 0.69 au and then traveled with the constant velocity of the ambient solar wind. These findings highlight the importance of background solar wind in determining the interplanetary evolution and global morphology of ICMEs up to Mars distance. Observations from multiple locations are invaluable for space weather studies at Mars and merit more exploration in the future

Mature landfill leachate treatment using granular sludge-based reactor (GSR) via nitritation/denitritation: Process startup and optimization

Mature landfill leachate wastewater (LLW) was characterized by high ammonia, refractory chemical oxygen demand (COD) and heavy metal contents, which limits the nitrogen removal in conventional activated sludge systems. Granular sludge is known to be more resistant to toxic compounds because of its dense structure and diverse microbial community. Here, granular sludge-based reactor (GSR) was applied with nitritation/denitritation (Nit/DNit) process for effective ammonia-rich mature LLW treatment at 20 °C. After a short startup period, the efficiencies of ammonia removal and total inorganic nitrogen removal stabilized at 99 % and 93 %, respectively, under a hydraulic retention time (HRT) of 6 h. High ammonia oxidation rate (~ 0.64 g N/g VSS/d) was achieved, with ~93 % ammonia conversing to nitrite before being reduced to nitrogen gas. Microbial analysis results revealed that Nitrosomonas (ammonia oxidizing bacteria) and Thauera (denitrifiers) were the dominant bacteria with key functional genes involved in the Nit/DNit. With an increase in the LLW loading, increased ammonia oxidation rates and biomass retention were also observed. This study demonstrated that granular sludge-based technology is feasible for mature LLW treatment.</p

Discrimination of Fresh Tobacco Leaves with Different Maturity Levels by Near-Infrared (NIR) Spectroscopy and Deep Learning

The maturity affects the yield, quality, and economic value of tobacco leaves. Leaf maturity level discrimination is an important step in manual harvesting. However, the maturity judgment of fresh tobacco leaves by grower visual evaluation is subjective, which may lead to quality loss and low prices. Therefore, an objective and reliable discriminant technique for tobacco leaf maturity level based on near-infrared (NIR) spectroscopy combined with a deep learning approach of convolutional neural networks (CNNs) is proposed in this study. To assess the performance of the proposed maturity discriminant model, four conventional multiclass classification approaches—K-nearest neighbor (KNN), backpropagation neural network (BPNN), support vector machine (SVM), and extreme learning machine (ELM)—were employed for a comparative analysis of three categories (upper, middle, and lower position) of tobacco leaves. Experimental results showed that the CNN discriminant models were able to precisely classify the maturity level of tobacco leaves for the above three data sets with accuracies of 96.18%, 95.2%, and 97.31%, respectively. Moreover, the CNN models with strong feature extraction and learning ability were superior to the KNN, BPNN, SVM, and ELM models. Thus, NIR spectroscopy combined with CNN is a promising alternative to overcome the limitations of sensory assessment for tobacco leaf maturity level recognition. The development of a maturity-distinguishing model can provide an accurate, reliable, and scientific auxiliary means for tobacco leaf harvesting

Responses of various carbon to nitrogen ratios to microbial communities, kinetics, and nitrogen metabolic pathways in aerobic granular sludge reactor

The role of different ammonia concentrations (mg N/L) (of 100 (carbon to nitrogen ratio (C/N) = 12; Stage I), 200 (C/N = 6; Stage II), 400 (C/N = 3; Stage III) and 200 (C/N = 6; Stage IV)) in nitrogen metabolic pathways, microbial community, and specific microbial activity were investigated in an aerobic granular sludge reactor. Heterotrophic ammonia oxidizing bacteria (HAOB) showed higher ammonia oxidation rates (AORs) than autotrophic ammonia oxidizing bacteria (AAOB) at higher C/N conditions (Stages I and II). Paracoccus was the dominant HAOB. AAOB, with only 0.2–0.3 % in relative abundance, showed 2.7-fold higher AORs than HAOB at elevated ammonia and free ammonia (FA) concentrations with C/N at 3. Nitrosomonas and a genus in Nitrosomondaceae family were the major AAOB. This study proposed that FA inhibition on heterotrophic bacteria might be the mechanism that contributes to the development of the autotrophic ammonia oxidation pathway and enrichment of AAOB.</p

Effective N2O emission control during the nitritation/denitritation treatment of ammonia rich wastewater

Nitritation/denitritation (Nit/DNit) is widely applied as a cost-effective nitrogen reduction strategy for ammonia rich wastewater treatment compared to conventional nitrification/denitrification processes. However, Nit/DNit processes have often been reported to lead to high nitrous oxide (N2O) emission. Here, N2O emissions were effectively suppressed in a single stage Nit/DNit sequencing batch reactor (SBR) treating ammonia rich digester sludge thickening lagoon supernatant at room temperature (20 °C). The impacts of alternating frequencies of aerobic/anoxic phases on reactor performance and N2O emissions were investigated. With the same hydraulic retention time (HRT), N2O production from 2 subcycles of aerobic/anoxic phases was 9.73% of the removed total inorganic nitrogen (TIN), whereas 14 subcycles of aerobic/anoxic phases reduced the N2O production to 1.53% of the removed TIN. Aerobic phases accounted for > 83% of the total N2O emission, whereas anoxic phases accounted for 2O emission throughout the operation. Aerobic N2O emissions correlated positively with the nitrite accumulated, and anoxic N2O emissions correlated negatively with the nosZ/(nirK+nirS) gene ratio. Changes in the phase alternation frequency did not negatively impact the TIN removal efficiency, which was maintained at 98% throughout the reactor operation. Mechanisms associated with N2O emission suppression were also discussed in the present study.</p

Market clearing price forecast for power peak shaving auxiliary service

The use of new energy to generate electricity in the power system and the large-scale increase of new energy grid connection has led to increasingly insufficient power system regulation, in order to solve this problem, the peak shaving auxiliary service market came into being.This article comprehensively analyzes the factors those affect the market clearing price of power peak shaving auxiliary services: The macro factors include energy economic policies (renewable energy and electric energy substitution), technological innovation, market operation rules, etc., and the micro factors include the quotation and demand of thermal power plants and wind power generation.The power peak shaving auxiliary service market is an important part of the power market. Its appearance makes the grid operation safer and more reliable, and the reasonable fluctuation of clearing prices and total market costs reflects the market’s sensitivity to peak shaving resource demand.This paper uses the BP neural network model to select 31 consecutive days of peak shaving auxiliary service clearing price data in North China for prediction

Enhancing biological dissolved organic nitrogen removal in landfill leachate wastewater: The role of sodium acetate co-metabolism

Dissolved organic nitrogen (DON) comprises approximately 25% of dissolved nitrogen in landfill leachate wastewater (LLW), posing potential risks such as stimulating algal growth and forming disinfection by-products if not treated properly. While DON characterization and removal by physicochemical methods in wastewater treatment systems have been examined, biological strategies for effective DON removal remain less developed. This study explores the influence of sodium acetate addition during denitrification process on LLW DON removal. With sodium acetate addition (Stage I), we achieved 99% ammonia removal, 94% total inorganic nitrogen (TIN) removal, and 45% DON removal. Fourier-transform ion cyclotron resonance mass spectrometry (FTICR-MS) results suggested the majority of sulfur-containing DON molecules were eliminated in Stage I. Conversely, in the absence of sodium acetate (Stage II), while 99% ammonia removal was maintained, TIN removal dropped to around 10%, and DON concentrations (largely sulfur-containing DON) increased by approximately 22%. Cycle tests revealed similar DON reductions in the aerobic phase across both stages, whereas in the anoxic phase, DON concentrations decreased in Stage I but increased in Stage II. Functional gene prediction indicated higher expression of decarboxylase and deaminase genes in Stage I compared to Stage II. Consequently, this study posits that sodium acetate addition enhances DON removal, potentially via co-metabolism.</p

Enhancing anammox process with granular activated carbon: A study on Microbial Extracellular Secretions (MESs)

Granular activated carbon (GAC), a porous carbon-based material, provides increased attachment space for functional microorganisms and enhances nitrogen removal by facilitating extracellular electron transfer in the anammox process. This study investigates the effects of GAC on the biosynthesis of microbial extracellular secretions (MESs) and explores the roles of these secretions in anammox activities. Four lab-scale reactors were operated: two downstream UASB reactors (D1 and D2) receiving effluents from the upstream UASB reactors (U1: no-GAC, U2: yes-GAC). Our results indicate that MESs were enhanced with the addition of GAC. The effluent from U2 exhibited a 59.62 % higher amino acid content than that from U1. These secretions contributed to an increase in the nitrogen loading rate (NLR) in the downstream reactors. Specifically, NLR in D1 increased from 130.5 to 142.7 g N/m3/day, and in D2, it escalated from 137.5 to 202.8 g N/m3/day, likely through acting as cross-feeding substrates or vital nutrients. D2 also showed increased anammox bacterial activity, enriched Ca. Brocadia population and hao gene abundance. Furthermore, this study revealed that D2 sludge has significantly higher extracellular polymeric substances (EPS) (48.71 mg/g VSS) and a larger average granule size (1.201 ± 0.119 mm) compared to D1 sludge. Overall, GAC-stimulated MESs may have contributed to the enhanced performance of the anammox process.</p

Deciphering the role of granular activated carbon (GAC) in anammox: Effects on microbial succession and communication

Anaerobic ammonium oxidation (anammox) offered an energy-efficient option for nitrogen removal from wastewater. Granular activated carbon (GAC) addition has been reported that improved biomass immobilization, but the role of GAC in anammox reactors has not been sufficiently revealed. In this study, it was observed that GAC addition in an upflow anaerobic sludge blanket (UASB) reactor led to the significantly shortened anammox enrichment time (shortened by 45 days) than the reactor without GAC addition. The nitrogen removal rate was 0.83 kg N/m3/day versus 0.76 kg N/m3/day in GAC and non-GAC reactors, respectively after 255 days’ operation. Acyl-homoserine lactone (AHL) quorum sensing signal molecule C8-HSL had comparable concentrations in both anammox reactors, whereas the signal molecule C12-HSL was more pervasive in the reactor containing GAC than the reactor without GAC. Microbial analysis revealed distinct anammox development in both reactors, with Candidatus Brocadia predominant in the reactor that did not contain GAC, and Candidatus Kuenenia predominant in the reactor that contained GAC. Denitrification bacteria likely supported anammox metabolism in both reactors. The analyses of microbial functions suggested that AHL-dependent quorum sensing was enhanced with the addition of GAC, and that GAC possibly augmented the extracellular electron transfer (EET)-dependent anammox reaction.</p