Lost Gas Mechanism and Quantitative Characterization during Injection and Production of Water-Flooded Sandstone Underground Gas Storage

A gas–water two-phase fluid is present in a reservoir before a water-flooded sandstone gas reservoir is rebuilt. Therefore, in the process of injection and production of the rebuilt underground gas storage, the injected gas is easily blocked by the water in the pores, and the efficiency is low, resulting in a significant loss of gas. The study completely utilizes the geological data and dynamic operation monitoring data of a water-flooded sandstone underground gas storage and clarifies the rule of the gas–water three-phase seepage in a high-intensity injection–production process. Moreover, the main control factors of the low efficiency of this type of underground gas storage are clarified. The lost gas generated in the injection–production process is described from two aspects: microcosmic experiment and macroscopic law analysis. The type, mechanism, and occurrence state of the loss gas are clearly defined, its main type is “water trapped gas”, it formed when the gas rushing into the water area under high pressure and surrounded by water, and its occurrence of this kind of lost gas is mainly sporadic or continuous free gas. A gas–water two-phase mathematical model that can simulate the high-intensity injection–production process is set up according to the experimental result, this model is used to simulate the operation process of the Ban 876 underground gas storage. Based on the simulation results, the gas–water macroscopic movement rule and macroscopic accumulation mode of the lost gas are defined, and then the collection area of the lost gas is predicted and quantitatively described. The calculation results show that the lost gas in one cycle is about 775 × 104 m3, which are mainly concentrated in the inner of the gas-water transition zone. According to the numerical simulation result, six new wells have been designed to develop its internal lost gas, they all have good predictions, can increase the working gas volume of 3000 × 104 m3 and reduce the single cycle lost gas by 50%, which is only 326 × 104 m3. This provides guidance for the expansion and exploitation of the same type of water-flooded sandstone underground gas storage

Edge Collaborative Online Task Offloading Method Based on Reinforcement Learning

With the vigorous development of industries such as self-driving, edge intelligence, and the industrial Internet of Things (IoT), the amount and type of data generated are unprecedentedly large, and users’ demand for high-quality services continues to increase. Edge computing has emerged as a new paradigm, providing storage, computing, and networking resources between traditional cloud data centers and end devices with solid timeliness. Therefore, the resource allocation problem in the online task offloading process is the main area of research. It is aimed at the task offloading problem of delay-sensitive customers under capacity constraints in the online task scenario. In this paper, a new edge collaborative online task offloading management algorithm based on the deep reinforcement learning method OTO-DRL is designed. Based on that, a large number of simulations are carried out on synthetic and real data sets, taking obstacle recognition and detection in unmanned driving as a specific task and experiment. Compared with other advanced methods, OTO-DRL can well realize the increase in the number of tasks requested by mobile terminal users in the field of edge collaboration while guaranteeing the service quality of task requests with higher priority

Fundamental researches on graphene/rubber nanocomposites

Graphene has exceptionally high surface area, mechanical properties, electrical conductivity, thermal conductivity, and gas-barrier performance, thus it is considered as an ideal multifunctional filler for rubbers. However, harnessing these properties in rubber nanocomposites requires us to carefully tailor the dispersion state of graphene, the vulcanization kinetics, the interfacial interaction and so on. This review summarized our recent works on how to disperse graphene homogeneously in rubber matrix, what influence of graphene or graphene oxide on the vulcanization behavior of the rubber nanocomposites, how to design a compact filler network in the rubber matrix, and how to engineer a strong interfacial interaction between graphene and rubber. These fundamental researches give us some thumb rules to develop graphene/rubber nanocomposites with significantly improved mechanical properties, gas-barrier performance, thermal stability, electric conductivity, antioxidation ability as well as some functionalities. Keywords: Graphene, Rubber, Nanocomposit

Annealing effect of micro-alloying on the microstructure and properties of Cu-10Zn alloy

The effect of Fe and P (Ni and Si) on the microstructure and properties of Cu-10Zn alloys has been investigated using hardness test, electrical conductivity measurement, optical microscopy and transmission electron microscopy. γ-Fe precipitates formed during the aging process, but there is almost no effect of precipitation strengthening on the Cu-Zn-Fe-P alloy and sparsely Fe3P precipitates existed in the matrix. After homogenization treatment at 900°C for 2h, hot rolling by 80%, cold rolling by 80%, and ageing treatment at 400°C for 30min, Cu-Zn-Ni-Si alloy obtained good combinations of hardness (219.8HV) and electrical conductivity(28.2%IACS). Ni2Si precipitates formed during aging process and the crystal orientation relationship between matrix and precipitates is:(200)α || (100)δ, [100]α || [010]δ,. Compared with Cu-Zn-Fe-P, Cu-Zn-Ni-Si has finer grains, and the precipitation strengthening effect is more obvious

Effect of Artificial Supplementary Lighting During Autumn and Winter on Leaf Senescence and Development of Winter Fruits of 'Shine Muscat' Grape

【Objective】In recent years, grape industry has developed rapidly in Guangdong Province, which has been a high-profit grape production region where two crops of grape berry can be harvested in a year. However, the short day photoperiod and chilling temperatures in autumn and winter induce systematic leaf senescence, which is unfavorable for over-winter berry development and quality formation in grape. In the study, the effect of artificial supplementary lighting on leaf senescence and berry development in 'Shine Muscat' grape were explored, with an aim to provide technical basis for maintaining leaf function and berry development in winter.【Method】From mid-October, 8-year-old 'Shine Muscat' plants on rootstock of '5BB' were treated with 3 μmol/m2·s red and blue LED light (5∶1) belts, which were placed above the leaves at the fruit cluster node. Light supplementary was carried out from 18:00 to 24:00 until the berries became mature. Changes in chlorophyll index (SPAD value), photosynthetic parameters (Pn) of the leaves at the fruit cluster node and horizontal and vertical diameters of berries were traced, and single berry weight, cluster weight and total soluble solid (TSS) content were collected at mature period.【Result】After 6 weeks of supplementary lighting treatment, leaves at the cluster node in the control plants became yellowing with decreasing SPAD value. While artificial lighting treatment was effective to suppress leaf chlorosis in winter, with significantly lower SPAD decreasing range. After 10 weeks of treatment, leaves at various nodes in supplementary lighting treatment were higher than those at corresponding nodes in the control plants, suggesting that artificial lighting suppressed systematic leaf senescence in winter. The Pn of both lighting treatment and the control plants decreased dramatically from mid-November to late December. However, the decreasing range of Pn was smaller in the lighting treatment. Pn had no significant correlation with stomatal conductance (Gs), but was extremely negatively correlated to mesophyll CO2 concentration (Ci), indicating the reduction of Pn during leaf senescence in winter was mainly caused by non-stomatal limitation. Supplementary lighting treatment maintained Pn via overcoming both stomatal and non-stomatal limitations. the supplementary lighting treatment, significantly increased single berry weight (10.8 g VS 8.8 g), promoted berry horizontal diameter, slightly increased single cluster weight, but significantly reduced total soluble solids (15.0% VS 16.7%).【Conclusion】The results show that supplementary lighting treatment is effective to delay systematic leaf senescence in winter and promote berry growth. It is recommended to use supplementary LED lighting during over-winter grape cultivation in Guangzhou or in regions with similar climate. However, measures should be taken to promote TSS accumulation in the berry

Cyclic di-adenosine monophosphate regulates the osteogenic and adipogenic differentiation of hPDLSCs via MAPK and NF-κB signaling

Cyclic di-adenosine monophosphate (c-di-AMP) is a bacterial second messenger that can be recognized by infected host cells and activate the immunoinflammatory response. The purpose of this study is to demonstrate the effect of c-di-AMP on the differentiation of human periodontal ligament stem cells (hPDLSCs) and its underlying mechanisms. In the present study, we find that the gingival crevicular fluid (GCF) of patients with chronic periodontitis has a higher expression level of c-di-AMP than that of healthy people. In vitro, c-di-AMP influences the differentiation of hPDLSCs by upregulating Toll-like receptors (TLRs); specifically, it inhibits osteogenic differentiation by activating NF-κB and ERK/MAPK and promotes adipogenic differentiation through the NF-κB and p38/MAPK signaling pathways. Inhibitors of TLRs or activated pathways reduce the changes induced by c-di-AMP. Our results establish the potential correlation among bacterial c-di-AMP, periodontal tissue homeostasis and chronic periodontitis pathogenesis

Comparison of nanovesicles derived from Panax notoginseng at different size: physical properties, composition, and bioactivity

AimPlant-derived nanovesicles have emerged as potential agents for combating tumors. In this study, we investigated the inhibitory effects of Panax notoginseng-derived nanovesicles (PnNVs) on the proliferation and migration of squamous cell carcinoma. Additionally, we explored the relationship between plant tuber size and the physical properties, composition and bioactivity of these nanovesicles.MethodsWe isolated PnNVs from Panax notoginseng tubers of varying sizes: small-sized (s_PnNVs), medium-sized (m_PnNVs) and large-sized (l_PnNVs), and evaluated for size, potential, and morphology. Cellular uptake efficiency was assessed using confocal microscopy and flow cytometry. The ability of different PnNVs to inhibit oral squamous cell carcinoma cells was evaluated using plate cloning, CCK8 assay, and scratch healing assay. Off-target metabolomics was used to compare metabolic compounds of different PnNVs.ResultsOur findings revealed that s_PnNVs exhibited lower potential but had the highest cellular uptake efficiency, whereas m_PnNVs were characterized by the smallest size and lowest cellular uptake efficiency. Notably, m_PnNVs demonstrated the most effective inhibition of squamous cell carcinoma growth and migration. Compositional analyses showed that PnNVs were rich in proteins and contained lower levels of RNA, with l_PnNVs having the highest protein content. Furthermore, untargeted metabolomics analysis revealed a significant increase in the expression of specific antitumour-related metabolites in m_PnNVs compared to s_PnNVs and l_PnNVs.ConclusionOverall, our results underscore the influence of plant tuber size on the bioactivity of the nanovesicles from which they are derived, emphasizing its importance for experimental design and study reproducibility

High‐Efficiency Broadband Achromatic Metadevice for Spin‐to‐Orbital Angular Momentum Conversion of Light in the Near‐Infrared

Spin‐orbital angular momentum conversion (SOC) of light has found applications in classical and quantum optics. However, the existing SOC elements suffer severe restrictions on broadband integrated applications at miniature scales, due to bulky configurations, single function, and failing to control the dispersion. Herein, a high‐efficiency broadband achromatic method for independently and elaborately engineering the dispersion and the SOC of light based on a cascaded metasurface device is proposed. The metadevice is capable of efficiently decoupling the SOC from the modulation of dispersion with high‐broadband focusing efficiency up to 75%. For the proof of concept, the generation of high‐efficiency achromatic‐focused and spin‐controlled optical vortices with switchable topological charge (lσ=+1=1 and lσ=−1=2) is successfully demonstrated. The presence of achromatically and highly concentrated optical vortices with tunable photonic angular momentum using spin as an optical knob makes the proposed ultracompact and multifunctional metadevice a promising platform for optical micromanipulation at nanoscale dimensions

Evaluating efficacy and safety of sub-anesthetic dose esketamine as an adjuvant to propofol/remifentanil analgosedation and spontaneous respiration for children flexible fibreoptic bronchoscopy: a prospective, double-blinded, randomized, and placebo-controlled clinical trial

Background: Flexible fiberoptic bronchoscopy (FFB) for children is widely performed under sedation. Currently, the optimal sedation regimen remains unclear. Esketamine is an N-methyl-D-aspartic acid (NMDA) receptor antagonist, which has stronger sedative and analgesic effects and exerts less cardiorespiratory depression than other sedatives. The purpose of this study was to evaluate whether a subanesthetic dose of esketamine as an adjuvant to propofol/remifentanil and spontaneous ventilation compared with control reduces the procedural and anesthesia-related complications of FFB in children.Materials and methods: Seventy-two children ≤ 12 years of age who were scheduled for FFB were randomly assigned, in a 1:1 ratio, to the esketamine-propofol/remifentanil (Group S, n = 36) or to the propofol/remifentanil group (Group C, n = 36). All children were retained spontaneous ventilation. The primary outcome was the incidence of oxygen desaturation (respiratory depression). Perioperative hemodynamic variables, blood oxygen saturation (SPO2), end-tidal partial pressure of carbon dioxide (PetCO2), respiratory rate (R), and the Bispectral index (BIS), induction time, procedural time, recovery time, the time to the ward from the recovery room, consumption of propofol and remifentanil during the procedure and the appearance of adverse events, including paradoxical agitation following midazolam administration, injection pain, laryngospasm, bronchospasm, PONV, vertigo, and hallucination were also compared.Results: The incidence of oxygen desaturation was significantly lower in Group S (8.3%) compared to Group C (36.1%, p = 0.005). The perioperative hemodynamic profile including SBP, DBP, and HR were more stable in Group S than that in Group C (p < 0.05). Consumption of propofol and remifentanil was lower in Group S than in Group C (p < 0.05). Furthermore, PAED scores, cough scores and injection pain were lower in the Group S than in Group C (p < 0.05). The recovery time of Group S was slightly longer than that of Group C (p < 0.05). Nobody happened paradoxical agitation following midazolam administration, PONV, vertigo, and hallucinations in both groups (p > 0.05).Conclusion: Our findings indicate that a subanesthetic dose of esketamine as an adjuvant to propofol/remifentanil and spontaneous respiration is an effective regimen for children undergoing FFB. Our findings will provide a reference for clinical sedation practice during these procedures in children.Clinical Trail Registration: Chinese clinicaltrials.gov registry (identifier: ChiCTR2100053302)

A brain stress test: Cerebral perfusion during memory encoding in mild cognitive impairment

Arterial spin labeled perfusion magnetic resonance imaging (ASL MRI) provides non-invasive quantification of cerebral blood flow, which can be used as a biomarker of brain function due to the tight coupling between cerebral blood flow (CBF) and brain metabolism. A growing body of literature suggests that regional CBF is altered in neurodegenerative diseases. Here we examined ASL MRI CBF in subjects with amnestic mild cognitive impairment (n = 65) and cognitively normal healthy controls (n = 62), both at rest and during performance of a memory-encoding task. As compared to rest, task-enhanced ASL MRI improved group discrimination, which supports the notion that physiologic measures during a cognitive challenge, or “stress test”, may increase the ability to detect subtle functional changes in early disease stages. Further, logistic regression analysis demonstrated that ASL MRI and concomitantly acquired structural MRI provide complementary information of disease status. The current findings support the potential utility of task-enhanced ASL MRI as a biomarker in early Alzheimer's disease