Experimental research on the effect caused by effective stress change in injection production capacity of carbonate reservoir

The effective stress of the reservoir rock in the underground gas storage (UGS) changes with the multi cycle injection and production, which changes the physical characteristics of the reservoir and affects the injection production capacity of the UGS. Taking carbonate fracture-pore type gas storage as the research object, combined with the actual production of UGS, establish a set of experimental evaluation methods based on production characteristics; Core damage evaluator, overburden pressure porosimeter and scanning electron microscope are used to carry out experimental research on the impact of effective stress change on injection production capacity, quantitative analysis of reservoir internal characteristics, multi cycle injection and production and effect of effective stress action time on injection-production capacity. The results show, the experimental method established based on the actual production characteristics of the UGS, simulation of multi cycle injection and production by forward and reverse displacement, simulation of effective stress change under constant confining pressure and variable internal pressure, the experimental evaluation of the injection production capacity of the simulation multi cycle injection and production of the UGS is realized; The change of effective stress makes the reservoir seepage characteristics worse and the reservoir space smaller, injection-production coefficient (Szc) is positively correlated with the internal characteristic value of the reservoir, the larger the internal characteristic value of the reservoir, the higher Szc, and the better the injection production capacity; The injection production capacity of the UGS reservoir deteriorates with the increase of the injection production cycle, in the 4th injection production cycle, the injection production capacity of the UGS changes from moderately strong to moderately weak; The damage of effective stress to the injection production capacity of UGS mainly occurs in the initial stage of injection production, and the damage tends to be stable with the progress of injection production. The conclusion is that the change of effective stress in carbonate fracture-pore type gas storage makes the injection-production capacity of the reservoir worse, it is proposed to carry out reservoir reconstruction before the UGS is put into operation, and expand the capacity of the gas storage after the completion of the 3rd injection and production cycle, which can effectively offset the impact of the decline of injection production capacity of the UGS and play the role of reservoir protection, it provides a constructive idea for improving the operation efficiency of the UGS

Domain Adaptive Attention Model for Unsupervised Cross-Domain Person Re-Identification

Person re-identification (Re-ID) across multiple datasets is a challenging yet important task due to the possibly large distinctions between different datasets and the lack of training samples in practical applications. This work proposes a novel unsupervised domain adaption framework which transfers discriminative representations from the labeled source domain (dataset) to the unlabeled target domain (dataset). We propose to formulate the domain adaption task as an one-class classification problem with a novel domain similarity loss. Given the feature map of any image from a backbone network, a novel domain adaptive attention model (DAAM) first automatically learns to separate the feature map of an image to a domain-shared feature (DSH) map and a domain-specific feature (DSP) map simultaneously. Specially, the residual attention mechanism is designed to model DSP feature map for avoiding negative transfer. Then, a DSH branch and a DSP branch are introduced to learn DSH and DSP feature maps respectively. To reduce domain divergence caused by that the source and target datasets are collected from different environments, we force to project the DSH feature maps from different domains to a new nominal domain, and a novel domain similarity loss is proposed based on one-class classification. In addition, a novel unsupervised person Re-ID loss is proposed to take full use of unlabeled target data. Extensive experiments on the Market-1501 and DukeMTMC-reID benchmarks demonstrate state-of-the-art performance of the proposed method. Code will be released to facilitate further studies on the cross-domain person re-identification task

Occurrence Regularity of Methane Gas Molecules in Composite Nanopores: A Molecular Simulation Study

AbstractTo understand the occurrence regularity of methane gas molecules in composite nanopores, the effects of temperature, pressure, size of nanopore, and burial depth on the occurrence state of methane were studied theoretically by using the grand canonical Monte Carlo and molecular dynamic simulation methods. By comparing the results available in the literature, the reasons for the difference in the occurrence states of methane molecules in nanopores were analyzed, and a reasonable occurrence regularity of methane was proposed, which provides corresponding suggestions for the actual exploitation of shale gas. The results indicated that the methane gas molecules existed in nanopore only in the adsorption and transition states under different environmental conditions. They were preferentially adsorbed at the strong adsorption sites on the nanopore surface to form a stable adsorption layer. After the adsorption layer reached saturation, a transition layer with higher density than that of bulk methane was formed at the nanopore center. The total adsorption capacity of methane decreased gradually with an increase in the internal temperature of shale reservoirs and increased with an increase in nanopore size. In addition, the average amount of methane stored in the nanopore increased at a deeper burial depth. The occurrence state of methane under different pressure ranges was controlled under different action mechanisms. Under low pressure (P<20 MPa), the adsorption of methane molecules was controlled by the number of strong adsorption sites on the nanopore surface, where the density peak intensity of the adsorption layer increased with the pressure. However, under high pressure (P>20 MPa), the adsorption was controlled by the diffusion process of methane molecules in the organic matter layer, where both the adsorption and transition layers reached the saturation state, and excessive methane molecules diffused deeper into the kerogen layer. The approach to effectively improve the recovery efficiency was to inject water or carbon dioxide into the shale reservoir where the water or carbon dioxide molecules occupy strong adsorption positions than the methane molecules adsorbed originally under the competitive adsorption effect, and the adsorbed methane molecules were transformed to a free state

First detection of Cryptosporidium spp. in red-bellied tree squirrels (Callosciurus erythraeus) in China

Cryptosporidium spp. are opportunistic pathogens that cause diarrhea in a variety of animal hosts. Although they have been reported in many animals, no information has been published on the occurrence of Cryptosporidium spp. in red-bellied tree squirrels (Callosciurus erythraeus). A total of 287 fecal specimens were collected from Sichuan province in China; the prevalence of Cryptosporidium spp., measured by nested-PCR amplification of the partial small-subunit (SSU) rRNA gene, was 1.4% (4/287). Three different Cryptosporidium species or genotypes were identified: Cryptosporidium parvum (n = 1), Cryptosporidium wrairi (n = 1), and Cryptosporidium rat genotype II (n = 2). The present study is the first report of Cryptosporidium infection in red-bellied tree squirrels in China. Although there is a relatively low occurrence of Cryptosporidium, the presence of C. parvum and C. wrairi, which were previously reported in humans, indicates that red-bellied tree squirrels may be a source of zoonotic cryptosporidiosis in China

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Phosphine-Catalyzed Asymmetric Synthesis of α‑Quaternary Amine via Umpolung γ‑Addition of Ketimines to Allenoates

A first phosphine-catalyzed enantioselective umpolung γ-addition of ketimines to allenoates has been developed that provides efficient access to optically active γ,δ-unsaturated α-amino esters and δ-amino esters with a chiral tertiary stereocenter under mild conditions. The salient features of this reaction include general substrate scope, mild conditions, good yields, high enantioselectivity, ease of scale-up to gram scale, and further transformations

The Complex Alarming Event Detecting and Disposal Processing Approach for Coal Mine Safety Using Wireless Sensor Network

Due to the complex environment of the coal mine, the accidents can occur at any time and often result in partial or total evacuation of mine personnel and could result in the loss of lives. Therefore, it is important and necessary to detect the accidents and generate a corresponding alarming disposal in time. This paper proposed a real-time complex alarming event detecting and disposal processing approach for coal mine safety using wireless sensor network. Firstly, we introduce the event and complex events model, offer fully customizable policies for event selection and consumption, and also describe the state-automata-based complex event detection algorithm. Then, we describe an event-driven service coordination pattern for the behavioral model, which is based on event-condition-action triggering with BPEL control flow realized using decoupled publish/subscribe semantics. Finally, the system implementation is presented and deployed in the coal mine, showing the effectiveness of the proposed approach

Curcumin Inhibits Heat-Induced Apoptosis by Suppressing NADPH Oxidase 2 and Activating the Akt/mTOR Signaling Pathway in Bronchial Epithelial Cells

Background: Heat causes bronchial epithelial cell apoptosis, which is a known factor contributing to airway damage during inhalation injury. Accumulating evidence has shown the effect of curcumin on inhibiting apoptosis. In this study, we investigated whether curcumin suppresses heat-induced apoptosis in bronchial epithelial cells and the underlying mechanism. Methods: Bronchial epithelial cell line 16HBE140 cells were incubated at either 42 °C, 47 °C, 52 °C, or 57 °C for 5 min in a cell incubator and then returned back to normal culture conditions (37 °C). An in vivo thermal inhalation injury rat model was established with a heat gun blowing hot air into the airway of rats. 16HBE140 cells and lung tissue were obtained for further study with or without curcumin treatment. Cell viability was determined by measuring the absorbance of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). 2',7'-dichlorofluorescein diacetate fluorescence was used as a measure of reactive oxygen species (ROS) production. Levels of Bcl2, Bax, α-ATP, cleaved Poly (ADP-ribose) polymerase (PARP), cleaved caspase-3, gp91phox, p47phox, p67phox, p22phox, p40phox, and Rac were determined by Western blotting. TUNEL staining was used to determine apoptosis. Results: Heat treatment triggered the apoptosis of 16HBE140 cells as shown by the increase in apoptosis molecular markers, including Bcl-2, Bax, cleaved PARP, and cleaved caspase-3. Administration of curcumin significantly inhibited apoptosis of 16HBE140 cells and suppressed the membrane translocation of NADPH oxidase 2 cytosolic components, as well as ROS production. Downregulation of Akt and mTOR phosphorylation induced by heat was also reversed by curcumin. Furthermore, we demonstrated that NADPH oxidase 2 is upstream of Akt/mTOR in heat-induced apoptosis. The protective role of curcumin on bronchial epithelia apoptosis was also confirmed in vivo by a rat inhalation injury model. Conclusion: This study demonstrates that one of the critical mechanisms underlying curcumin inhibiting heat-induced apoptosis is through suppressing NADPH Oxidase 2 and activating the Akt/mTOR signaling pathway in bronchial epithelial cells

Domain Adaptive Attention Learning for Unsupervised Person Re-Identification

Person re-identification (Re-ID) across multiple datasets is a challenging task due to two main reasons: the presence of large cross-dataset distinctions and the absence of annotated target instances. To address these two issues, this paper proposes a domain adaptive attention learning approach to reliably transfer discriminative representation from the labeled source domain to the unlabeled target domain. In this approach, a domain adaptive attention model is learned to separate the feature map into domain-shared part and domain-specific part. In this manner, the domain-shared part is used to capture transferable cues that can compensate cross-dataset distinctions and give positive contributions to the target task, while the domain-specific part aims to model the noisy information to avoid the negative transfer caused by domain diversity. A soft label loss is further employed to take full use of unlabeled target data by estimating pseudo labels. Extensive experiments on the Market-1501, DukeMTMC-reID and MSMT17 benchmarks demonstrate the proposed approach outperforms the state-of-the-arts