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The sedimentary evolution of distributive fluvial system in arid and low accommodation space sag: A case study of the lower fourth sub-member of Shahejie Formation from Bonan Sag in Zhanhua Depression, Bohai Bay Basin
The distributive fluvial system (DFS) mainly dominates sedimentary process of arid zones and is quite different from fans of mild climate zones. recent researchers focused on DFSs and try to reveal development law of DFSs in arid zones. However, different time scales of research from modern DFSs, ancient DFSs and physical simulation experiment induced debates on the sedimentary character and evolution of ancient DFSs. This paper constructs sedimentary model of ancient arid DFSs in constrain with sequence stratigraphy and sag structure for providing a new way to understand the ancient DFSs in arid zones. During the period of lower fourth sub-member of Shahejie Formation (Es4 x ), arid climate and low accommodation space developed in Bonan Sag. That provide well natural conditions for investigating the ancient DFSs in arid zones. The unique evolution of sequence stratigraphy and distinctive sag structure constructed two type distributive fluvial system in different topography in Bonan Sag during the period of Es4 x . In the gentle slope belt, the DFS transported sediments in a long distance and wide range. The DFS developed in large scale and thin sand body during the transgressive system tract (TST). As the sediment supply decreased, retrogradation and distal fan developed in the DFS during the regressive system tract (RST). The DFS of gentle slope belts shortened and narrowed during the RST stage. In the steep slope belt, more accommodation spaces generated with the high gradient. The concentration of accommodation constructed thick DFS with restricted distribution during the TST stage. During the RST stage, the sediment supply decreased and accommodation spaces became low and migrated with the evolution of sequence stratigraphy and sag structure. In response to the evolution of sediment supply and accommodation spaces, the DFS developed progradation in space with thinner sand body.
Journal Article
Drawing home
\"Summer has started in idyllic Sag Harbor, and for Emma Mapson that means greeting guests at the front desk of The American Hotel. But when one of the town's most famous residents, artist Henry Wyatt, dies suddenly, Emma learns he has mysteriously left his waterfront home - a self-designed masterpiece filled with his work - to her teenage daughter, Penny. Back in Manhattan, legendary art patron Bea Winstead's grief at her lifelong friend and former business partner Henry's passing turns to outrage at the news of his shocking bequest. How did these unknown locals get their hands on the estate? Bea, with her devoted assistant Kyle in tow, descends on Sag Harbor determined to reclaim the house and preserve Henry's legacy. While Emma fights to defend her daughter's inheritance, Bea discovers that Henry left a treasure trove of sketches scattered around town. With Penny's reluctant help, Bea pieces them together to find a story hidden in plain sight: an illustration of their shared history with an unexpected twist that will change all of their lives. Drawn together in their battle for the house, Emma and Bea are forced to confront the past while facing a future that challenges everything they believe about love, fate, and family.\"--Provided by publisher.
Book
Characteristics and evolution of faults in the north-central Yin'e Basin and the effects on the coal-seam in the Cretaceous strata
Research on the characteristics of faults and their evolutionary history since the Cretaceous in the Suhongtu-Dagu depressions can provide a theoretical basis for geological evaluation of the coal seams in the Suhongtu Formation in the northern-central region of the Yin'e Basin. Using 3-D seismic-logging inversion techniques, seismic stratigraphic calibration, stratigraphic sequence delineation, and thickness calculations on the Suhongtu-Dagu depressions were carried out to clarify the planar and profile distributions of the faults, as well as the evolutionary history of these faults and the tectonic history of the depressions. The results of this study revealed that the distribution of the faults in the Suhongtu-Dagu depressions in the northern part of the Yin'e Basin varies with region, and the fault system was multi-period, orthotropic, north-east-trending, and north-north-east-trending, with a certain degree of inheritance in terms of the geological setting. Three types of faults were identified: Y-shaped fractures, reverse Y-shaped fractures, and parallel fractures, which can be classified as Paleozoic-Cenozoic continuous syncline faults and intra-depression faults from the top of the Permian to the Upper Cretaceous series and inter-stratigraphic adjustment faults within the Cretaceous System, respectively. The evolution of these faults can be divided into three phases: the controlling faults were the faults that existed before the Early Cretaceous and had been active since then; synclinal faults that formed during the Early Cretaceous; and modified faults that formed since the Early Cretaceous. The development and modification of the coal seams in the Cretaceous Suhongtu Formation in the Hari, Kuanzihu, and Babei sags were strongly controlled and influenced by a multi-phase complex fault system.
Journal Article
A systematic review of real-time detection and classification of power quality disturbances
This paper offers a systematic literature review of real-time detection and classification of Power Quality Disturbances (PQDs). A particular focus is given to voltage sags and notches, as voltage sags cause huge economic losses while research on voltage notches is still very incipient. A systematic method based on scientometrics, text similarity and the analytic hierarchy process is proposed to structure the review and select the most relevant literature. A bibliometric analysis is then performed on the bibliographic data of the literature to identify relevant statistics such as the evolution of publications over time, top publishing countries, and the distribution by relevant topics. A set of articles is subsequently selected to be critically analyzed. The critical review is structured in steps for real-time detection and classification of PQDs, namely, input data preparation, preprocessing, transformation, feature extraction, feature selection, detection, classification, and characterization. Aspects associated with the type of disturbance(s) addressed in the literature are also explored throughout the review, including the perspectives of those studies aimed at multiple PQDs, or specifically focused on voltage sags or voltage notches. The real-time performance of the reviewed tools is also examined. Finally, unsolved issues are discussed, and prospects are highlighted.
Journal Article
Research on Improved Sag Control-based Microgrid Controller Strategy
Firstly, the basic equivalent model of inverter parallel connection is briefly introduced, and then the basic working principle of sag control is described. The sag control has a certain effect on the regulation of reactive power and active power, but when the line impedance is not equal, the reactive power distribution among the inverters cannot be reasonably dispatched and distributed. The robustness of the system is verified.
Journal Article
Meso-Cenozoic negative inversion model for the Linhe Depression of Hetao Basin, China
The Linhe Depression is the largest tectonic unit in the Hetao Basin. The recently discovered commercial oil flow in the structural trap of wells JH2X and S5 has proved that the Meso-Cenozoic strata in the Linhe Depression have great exploration potential. Research on the kinematic model for the Mesozoic–Cenozoic Linhe Depression is important for analysing the geological conditions of hydrocarbon accumulation. In this study, field observations, seismic interpretation and scaled analogue modelling are performed. The results prove that the Linhe Depression experienced different stages of tectonic evolution, such as compressional depression (K1l), conversion from contraction to uniform subsidence (K1g), extensional rifting (E2–N2) and strike-slip deformation (Q), during the Mesozoic–Cenozoic eras. The kinematic model of negative inverted basins was first established with the early differential compression superimposed by the late extension. The seismic interpretation and analogue modelling results show that Jilantai Sag in the southern part of the Linhe Depression was subjected to compression from the Bayanwulashan fold–thrust belt on the NW side and the Helanshan fold–thrust belt on the SE side during Early Cretaceous time. Meanwhile, the Hanghou Sag in the northern part of the Linhe Depression was only compressed by the Langshan fold–thrust belt from the NW direction. The rifted structure generated by the extension from the SE direction during the Cenozoic Era resulted in the negative inversion of the pre-existing thrusts in different patterns. The intensity of negative inversion is controlled by several key factors, such as dip angle and the patterns of thrust faults, along with different basement textures. The morphological changes in the forebulge zone developed during Early Cretaceous time are responsible for the development of the segmented Central fault zones in the Hanghou Sag.
Journal Article
Minimizing finite sums with the stochastic average gradient
We analyze the stochastic average gradient (SAG) method for optimizing the sum of a finite number of smooth convex functions. Like stochastic gradient (SG) methods, the SAG method’s iteration cost is independent of the number of terms in the sum. However, by incorporating a memory of previous gradient values the SAG method achieves a faster convergence rate than black-box SG methods. The convergence rate is improved from
O
(
1
/
k
)
to
O
(1 /
k
) in general, and when the sum is strongly-convex the convergence rate is improved from the sub-linear
O
(1 /
k
) to a linear convergence rate of the form
O
(
ρ
k
)
for
ρ
<
1
. Further, in many cases the convergence rate of the new method is also faster than black-box deterministic gradient methods, in terms of the number of gradient evaluations. This extends our earlier work Le Roux et al. (Adv Neural Inf Process Syst,
2012
), which only lead to a faster rate for well-conditioned strongly-convex problems. Numerical experiments indicate that the new algorithm often dramatically outperforms existing SG and deterministic gradient methods, and that the performance may be further improved through the use of non-uniform sampling strategies.
Journal Article
Detection of Three-Phase Voltage Sag under Multiple Power Quality Disturbances
Voltage sag is an unavoidable short-term power quality disturbance problem in the power system. Rapid and accurate detection of voltage sag characteristic quantities is the premise of dealing with the sag problem. Based on the principle of d-q transformation and ISOGI-QSG structure, this paper proposes a method for fast detection and identification of three-phase voltage sag. It describes the working principle of the improved SOGI in detail. In addition, the structure of three-phase voltage sag independent detection is analyzed, and a fast determination method for sag fault types is proposed. The advantages of this method compared with traditional three-phase voltage detection are verified by simulation comparison, and it still has good anti-interference ability and better dynamic performance under various power quality disturbances. Moreover, the detection speed can meet the time requirements of sensitive loads for dual power switching.
Journal Article
Aluminum Conductor Steel-Supported Conductors for the Sustainable Growth of Power Line Capacity: A Review and Discussion
Industrial development and population growth have increased the need for higher-capacity power transmission lines. Aluminum conductor steel-supported (ACSS) conductors, a type of high-temperature low-sag (HTLS) conductor, are now widely used in new designs and reconductoring applications. ACSS conductors are preferred over traditional aluminum conductor steel-reinforced (ACSR) conductors due to their high strength, low sag, and excellent thermal stability. These attributes have garnered significant interest from researchers, engineers, and manufacturers. This paper provides a comprehensive review of the structure, properties, testing methods, and environmental behavior of ACSS conductors.
Journal Article