Dynamic Sealing Behavior of Sand Self-Juxtaposition Windows on a Trap-Bounding Fault in a Natural Gas Storage Site

AbstractAn understanding of across-fault seals is essential for planning an injection/production strategy for a fault-bounded gas storage site. In addition, it is more likely to permit lateral leakage for a fault with sand self-juxtaposition windows. This paper is aimed at identifying the dynamic sealing behaviors of a sand self-juxtaposition fault on the geological and gas injection timescales. Banzhongbei gas storage site, China, was taken as a target area, and fault seals and hydrocarbon distributions within the original reservoirs were studied. The results showed that across-fault pressure differences of 0.085~0.146 MPa (equivalent to 41.6~71.5 m oil-column and 27.0~46.4 m gas-column heights) were supported by sand self-juxtaposition windows on the B816 fault, and the resultant absolute permeability (5.97×10−2~5.69×10−1 mD) of the fault was nearly 3~4 orders of magnitude lower than the average absolute permeability of reservoirs (1.16×102 mD). Gas composition contrasts, between the original and injection gas coupled with dynamic pressure monitoring data, indicated that lateral leakage occurred across sand self-juxtaposition windows under the condition of high across-fault pressure difference. However, the low-permeability fault showed strong negative influence on the efficiency of fluid flow in the model calculations and prolongs the timescales of pressure-difference decayed as much as 5 orders of magnitude relative to those of nonfault model calculations. These modeled dynamic sealing behaviors of sand self-juxtaposition windows may lead to a better understanding of the relative retardation of across-fault gas flow by weak sealing faults on the gas injection/production timescale

Machining of Aluminum Alloy

Import 23/07/2015Diplomová práce se zabývá kvalitou opracované hliníkové slitiny EN AW-6082, speciálně drsností povrchu a měřením a vyhodnocením složek řezných sil. Teoretická část objasňuje základní pojmy věnované čelnímu frézování, obrobitelnosti hliníku, obráběným materiálům, řezným podmínkám a geometrii obrábění. V návrhu experimentální části práce je popsáno použití stroje, nástroje a vyměnitelných břitových destiček, přístrojů na měření drsnosti, velikosti řezných sil a navržené řezné podmínky. V experimentální části práce jsou změřeny drsnosti povrchu a presentovány výsledky naměřených hodnot drsnosti Ra a Rz. Řezné síly byly měřeny na piezoelektrickém dynamometru.This master thesis is concerned with the quality of machined aluminium alloy EN AW-6082, especially surface roughness and the measurement and evaluation components of the cutting forces. The theoretical part explains the basic concepts of frontal milling, machinability aluminium, machined material, cutting conditions and geometry processing. In the proposal of the experimental part is described the using of machine, tool and indexable inserts, devices for measuring roughness, cutting forces and proposed cutting conditions. In the experimental part of the work are measured surface roughnesses and presented the results of the measured values of roughness Ra and Rz. Cutting forces were measured on the piezoelectric dynamometer.346 - Katedra obrábění, montáže a strojírenské metrologievelmi dobř

SQL Query Disassembler An Approach to Managing the Execution of Large SQL Queries

Current database workloads often consist of a mixture of short online transaction processing (OLTP) queries and large complex queries such as those typical of online analytical processing (OLAP). OLAP queries usually involve multiple joins, arithmetic operations, nested sub-queries, and other system or user-defined functions and they typically operate on large data sets. These resource intensive queries can monopolize the database system resources and negatively impact the performance of smaller, possibly more important, queries. In this thesis, we present an approach to managing the execution of large queries that involves the decomposition of large queries into an equivalent set of smaller queries and then scheduling the smaller queries so that the work is accomplished with less impact on other queries. We describe a prototype implementation of our approach for IBM DB2 ™ and present a set of experiments to evaluate the effectiveness of the approach. ii Acknowledgment

Feature-guided dynamic graph convolutional network for wetland hyperspectral image classification

Recently, graph convolutional networks (GCNs) has attracted wide attention on the wetland classification with limited samples. However, traditional approaches of superpixel generation rely on artificial experience and the spatial information is ignored during the construction of graph structure, which limits the classification performance. To address these problems, a feature-guided dynamic graph convolutional network (FG-DGCN) is proposed for wetland classification. First, a learnable superpixel generation module is proposed to generate adaptive superpixel boundaries, which composed of a pixel-wise feature enhancement block and a superpixel generation block. The former is utilized to improve the discrimination of features and the latter is applied to adjust the representation of superpixels by training. Second, a feature-guided adjacency matrix update mechanism is designed to dynamically capture and fuse the spectral and spatial correlations of graph nodes, promoting the aggregation of neighborhood information. Finally, the features are differentially projected back to the pixel space for wetland classification. Experiments on three wetland datasets demonstrate the superiority of FG-DGCN over state-of-the-art methods

Microstructures and mechanical properties of micro friction stir welding (μFSW) of 6061-T4 aluminum alloy

Micro friction stir welding (μFSW) was successfully performed to join the ultra-thin 6061-T4 sheet with the thickness of 0.5 mm. The optimum plunging depth of 0.05 mm was obtained and reduction ratio was lower than 0.2%. Based on better dynamic flow induced by the triflat pin, the good surface appearance at the wider process window was obtained, while the grain size at the nugget zone was finer than that by the taper pin. Increasing welding speed caused that tensile property increased firstly and then decreased with high welding speed than 500 mm/min. The maximum values of tensile strength and elongation of the μFSW joint using the triflat pin reached 220.3 MPa and 11.7%, which were 91.9% and 54.4% of base material, respectively. Keywords: Micro friction stir welding, Ultra-thin sheet, 6061-T4 alloy, Microstructure, Mechanical propert

Association of preterm outcome with maternal systemic lupus erythematosus: a retrospective cohort study

Abstract Background Maternal systemic lupus erythematosus (SLE) is at greater risk of pregnancy complications and is associated with increased risk of preterm delivery. However hardly any study has looked at the influence of SLE on the outcomes of preterm infants. This study aimed to explore the influence of SLE on the outcomes of preterm infants. Methods In this retrospective cohort study, preterm infants born to mothers with SLE from Shanghai Children’s Medical Center during 2012 to 2021 were enrolled. Infants were excluded if they were died during hospitalization or has major congenital anomalies and neonatal lupus. Exposure was defined as mother diagnosed SLE before or during pregnancy. Maternal SLE group was matched with Non-SLE group by gestational age, birth weight and gender. Clinical data has been extracted from patients’ records and registered. Major morbidities of premature and biochemical parameters in the two groups were compared using multiple logistic regression. Results One hundred preterm infants born to 95 mothers with SLE were finally enrolled. The mean (standard deviation) of gestational age and birth weight were 33.09 (7.28) weeks and 1768.50 (423.56) g respectively. There was no significant difference in major morbidities between SLE group and non-SLE group. Compared with non-SLE group, SLE off-spring had significantly lower leukocytes, neutrophiles after birth, neutrophils and platlet in one week (mean difference: -2.825, -2.001, -0.842, -45.469, respectively). Among SLE group, lower birth weight and smaller gestational age were observed in SLE mothers with disease active during pregnancy, kidney involved, blood system involved and not taking Aspirin during pregnancy. In the multivariable logistic regression analysis, exposure to aspirin during pregnancy reduced the risk of very preterm birth and increased the incidence of survive without major morbidities among preterm infants born to SLE mothers. Conclusion Born to mothers with SLE may not increase the risk of major premature morbidities, but the hematologic profile of SLE preterm infants may be different from preterm infants born to women without SLE. The outcome of SLE preterm infants is associated with maternal SLE status and may benefit from maternal aspirin administration

In Vitro and In Vivo Metabolomic Profiling after Infection with Virulent Newcastle Disease Virus

Newcastle disease (ND) is an acute, febrile, highly contagious disease caused by the virulent Newcastle disease virus (vNDV). The disease causes serious economic losses to the poultry industry. However, the metabolic changes caused by vNDV infection remain unclear. The objective of this study was to determine the metabolomic profiling after infection with vNDV. DF-1 cells infected with the vNDV strain Herts/33 and the lungs from Herts/33-infected specific pathogen-free (SPF) chickens were analyzed via ultra-high-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF-MS) in combination with multivariate statistical analysis. A total of 305 metabolites were found to have changed significantly after Herts/33 infection, and most of them belong to the amino acid and nucleotide metabolic pathway. It is suggested that the increased pools of amino acids and nucleotides may benefit viral protein synthesis and genome amplification to promote NDV infection. Similar results were also confirmed in vivo. Identification of these metabolites will provide information to further understand the mechanism of vNDV replication and pathogenesis