Constraints on jet formation mechanisms with the most energetic giant outbursts in MS 0735+7421

Giant X-ray cavities lie in some active galactic nuclei (AGNs) locating in central galaxies of clusters, most of these cavities are thought to be inflated by jets of AGNs. The jets can be either powered by rotating black holes or the accretion disks surrounding black holes, or both. In this work, we choose the most energetic cavity, MS 0735+7421, with stored energy ~ 10^62 erg, to constrain the jet formation mechanisms and the evolution of the central massive black hole in this source. The bolometric luminosity of the AGN in this cavity is ~ 10^(-5) L_Edd, however, the mean power of the jet required to inflate the cavity is estimated as ~ 0.02 L_Edd, which implies that the source has experienced strong outbursts previously. During outbursts, the jet power and the mass accretion rate should be significantly higher than its present values. We construct an accretion disk model, in which the angular momentum and energy carried away by jets is properly included, to calculate the spin and mass evolution of the massive black hole. In our calculations, different jet formation mechanisms are employed, and we find that the jets generated with the Blandford-Znajek (BZ) mechanism are unable to produce the giant cavity with ~ 10^62 erg in this source. Only the jets accelerated with the combination of the Blandford-Payne (BP) and BZ mechanisms can successfully inflate such a giant cavity, if the magnetic pressure is close to equipartition with the total (radiation+gas) pressure of the accretion disk. For dynamo generated magnetic field in the disk, such an energetic giant cavity can be inflated by the magnetically driven jets only if the initial black hole spin parameter a_0 > 0.95. Our calculations show that the final spin parameter a of the black hole is always ~ 0:9 - 0.998 for all the computational examples which can provide sufficient energy for the cavity of MS 0735+7421.Comment: 25 pages, 8 figures, accepted by Ap

Microfluidic Pore Model Study on Physical and Geomechanical Factors Influencing Fluid Flow Behavior in Porous Media

Fluid flow in porous media is a subject of fundamental importance and relevant to numerous engineering applications. The comprehensive description of fluid interaction parameters containing wetting properties, fluid-fluid displacement ratio, and capillary pressure, are inevitably needed. Moreover, the fine-grained sediments’ response to various pore fluids and migration in porous media influences reservoir geomechanical properties and pore clogging is essential to a better understanding of fluids flow behavior. This dissertation provides a detailed study of physical and geomechanical factors influencing fluids flow behavior in porous media. The two-dimensional micromodel tests have been conducted under a wide selection of fluids flow conditions. The experiments combined with pore network modeling are added to predict the fluid-fluid displacement ratio and capillary curves regarding different fluids. The fines’ geomechanical properties such as electrical sensitivity, compressibility, and hydraulic conductivity, together with pore plugging criteria are measured through various experiments including sedimentation, electrical sensitivity, and consolidation tests. Results of this research show that increase in injection fluid velocity, viscosity, contact angle, and a decrease in fluid’s interfacial tension can result in higher viscosity and capillary numbers, which leads to an improvement of the fluid-fluid displacement ratio in porous media. Experiments with the subsequently conducted simulation corroborate a higher capillary pressure is expected with a decrease in contact angle and an increase in interfacial tension. Meanwhile, estimation of capillary pressure can be achieved with measured fluids’ wetting properties at different stress levels. Besides, the findings indicate that fine sediments’ geomechanical properties and clogging criteria can be altered due to fines’ response to distinct pore fluids. The geomechanical properties of the different fine sediments also vary with pore fluid chemistry changes. And, fines clogging in porous media is observed under conditions of a lower pore throat width/fine size ratio, a higher fine concentration, a relatively higher flow rate, and the changed pore fluids. Additionally, the presence of a moving gas/liquid meniscus increases the fines clogging potential. In summary, an understanding of fluids’ physical and geomechanical properties, in addition to an identification of fines influences, can help to evaluate the performance of fluids flow in porous media

Subsurface discontinuity analysis & modeling for the federal waste disposal facility and compact waste disposal facility landfills

This research considers discontinuities mapped by Waste Control Specialists LLC to support the site conditions and performance analysis of the Compact Waste Disposal Facility and the Federal Waste Disposal Facility excavations constructed near Andrews, Texas. Discontinuities observed in excavation walls contain a limited number of discontinuities shoevidence of previous fluid movement. While no networks of such discontinuities were observed in the field, the potential for such networks may exist. This research is significant in understanding the performance of these waste facilities by modeling multiple realizations of possible fracture configurations in three-dimensional spatial models of the type of discontinuities observed in the field. The results show the low-angle discontinuities vastly outnumber the near-vertical discontinuities and most hydraulically significant discontinuities are shown with near-vertical orientation. Relatively few hydraulically significant discontinuities were observed across all mapped faces within the set of low-angle discontinuities. Furthermore, the proportion of vertical to horizontal discontinuities decreases with decreasing grain size, and most Genetic units had discontinuities in the upper half of a Genetic unit that were roughly horizontal and very few shoevidence of hydraulic significance. Three-dimensional models were created of the discontinuities in each of the geologic lagers surrounding both facilities using DFNModeler. These models were created using a statistical representation of the hydraulically significant discontinuities observed in each of the geologic units observed in the mapped areas of both facilities. In general, the variation in discontinuity properties do not show significant trends beyond the consistency with the geologic characteristics of each bed or layer, supporting a bedded but otherwise statistically consistent spatial model of the units. The model results shoa mean of maximum fracture network volume or compartment hull volume of 95.72 m3 and 188.59 m3 for the CWF and FWF, respectively. The maximum effective diameter or one-dimensional span of such hulls is small (3.57 m to 6.82 m) relative to the height of width of the excavation walls. The largest proportion of compartment hulls had a volume smaller than 8 m3 and a few hulls were larger than 18 m3. There is no evidence found in models of either the CWF or FWF that there is any credible potential for fluid flow within possible networks of discontinuities within these units in either the vertical direction or horizontal direction

Application of Sigma metrics in assessing the clinical performance of verified versus non-verified reagents for routine biochemical analytes

Introduction: Sigma metrics analysis is considered an objective method to evaluate the performance of a new measurement system. This study was designed to assess the analytical performance of verified versus non-verified reagents for routine biochemical analytes in terms of Sigma metrics. Materials and methods: The coefficient of variation (CV) was calculated according to the mean and standard deviation (SD) derived from the internal quality control for 20 consecutive days. The data were measured on an Architect c16000 analyser with reagents from four manufacturers. Commercial reference materials were used to estimate the bias. Total allowable error (TEa) was based on the CLIA 1988 guidelines. Sigma metrics were calculated in terms of CV, percent bias and TEa. Normalized method decisions charts were built by plotting the normalized bias (biasa: bias%/ TEa) on the Y-axis and the normalized imprecision (CVa: mean CV%/TEa) on the X-axis. Results: The reagents were compared between different manufacturers in terms of the Sigma metrics for relevant analytes. Abbott and Leadman’s verified reagents provided better Sigma metrics for the alanine aminotransferase assay than non-verified reagents (Mindray and Zybio). All reagents performed well for the aspartate aminotransferase and uric acid assays with a sigma of 5 or higher. Abbott achieved the best performance for the urea assay, evidenced by the sigma of 2.83 higher than all reagents, which were below 1-sigma. Conclusion: Sigma metrics analysis system is helpful for clarifying the performance of candidate non-verified reagents in clinical laboratory. Our study suggests that the quality of non-verified reagents should be assessed strictly

Audit research of large engineering projects based on blockchain technology

Large-scale projects have the characteristics of huge investment, long construction period, resource consumption and many project participants. The audit work is very important but the diffi culty is often very high. Blockchain technology has gradually entered the mainstream application with its characteristics of decentralization, openness and transparency, and data is diffi cult to tamper, which also brings new opportunities to engineering audit. This paper studies the application of blockchain technology in large-scale engineering audit, and explores the implementation method of large-scale engineering audit based on blockchain technology from the aspects of blockchain technology selection, platform framework construction, smart contract design, etc., to solve the problems of diffi culty in obtaining evidence, poor reliability of evidence and low effi ciency

Application of the disk instability model to all Quasi-Periodic Eruptions

After the first quasi-periodic eruptions (QPEs, GSN069) was reported in 2019, four other sources have been identified as QPEs or its candidate. However, the physics behind QPEs is still unclear so far, though several models have been proposed. Pan et al. (2022) proposed an instability model for the accretion disk with magnetically driven outflows in the first QPEs GSN 069, which is able to reproduce both the light curve and the evolution of spectrum fairly well. In this work, we exploit this model to all the QPEs. We imporve the calculations of the spectrum of disk by introducing a hardening factor, which is caused by the deviation of opacity from the blackbody. We find that the light curves and evolution of the spectra of the four QPEs or candidate can all be well reproduced by our model calculations.Comment: 8 pages, 7 figures, accepted for publication in Ap