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Accurate reactive load prediction can improve the accuracy and process of reactive power optimization for power grids and improve the control effect. The changes in the bus reactive load and active load are not synchronous, the base of the reactive load is small, nonlinear changes are abundant, and it is difficult to mine the inherent data trends. In view of the above problems, this paper proposes a method for predicting bus reactive loads based on deep learning. A bus reactive load prediction model is constructed based on a dual-input long short-term memory neural network to mine the detailed characteristics of active and reactive load data. Active and reactive loads are used as input and output data for the dynamic modeling of load time series data to form integrated forecasts of bus active and reactive loads. The experimental results show that this method can accurately predict the reactive power load of buses, and the prediction accuracy is better than that of time series and general long short-term memory neural network prediction models.

When large-scale wind power is connected to the power grid, the fluctuation and uncertainty in the wind power reduce the stability and accuracy of the grid's reactive voltage division results based on the electrical distance matrix and affect the grid's reactive power regulation. This paper proposes a grid reactive voltage partitioning method that considers the wind power stability and accuracy in a comprehensive manner. The wind power uncertainty and zoning results are characterized by the distribution of wind power forecast error intervals and changes in the zoning result nodes at different moments when the wind power is connected. Regarding volatility, according to the discretization of the probability distribution of the active power output at a certain time based on the wind power prediction, a calculation interval of the wind power output under a single cross-section is formed, and multiple sequential power flow sections within a long time scale are clustered and partitioned by an agglomeration hierarchical clustering method. Finally, an optimal zoning model of reactive voltage is established over a long time scale with the minimum comprehensive stability serving as the objective function. A simulation analysis of the improved IEEE39 node system shows that the partition combination can effectively increase the stability and accuracy of the reactive partitioning.

This paper describes recent advances in the effect of soil creep on the time-dependent deformation of deep braced excavation. The effect of soil creep is generally investigated using the observational method and the plain-strain numerical simulation method. The observational method is more applicable for deep braced excavations in soft clays constructed using the top-down method. The plain-strain numerical simulation method can be conveniently used for parametric analysis, but it is unable to capture the spatial characteristics of soil creep effect on lateral wall deflections and ground movements. The additional lateral wall deflections and ground movements that are generated due to the soil creep effect can account for as large as 30% of the total displacements, which highlights the importance of considering the effect of soil creep in deep braced excavations through soft clays. The magnitude of the displacements due to soil creep depends on various factors, such as excavation depth, elapsed period, unsupported length, and strut stiffness. Parametric analyses have indicated several effective measures that can be taken in practice to mitigate the detrimental effect of soil creep on the deformation of deep braced excavation. Based on the literature review, potential directions of the related future research work are discussed. This paper should be beneficial for both researchers and engineers focusing on mitigating the adverse effect of soil creep on the stability of deep braced excavations.

This paper presents a comparative analysis of two parallel hybrid magnet memory machines (PHMMMs) with different permanent magnet (PM) arrangements. The proposed machines are both geometrically characterized by a parallel U-shaped hybrid PM configuration and several q-axis magnetic barriers. The configurations and operating principles of the investigated machines are introduced firstly. The effect of magnet arrangements on the performance of the proposed machines is then evaluated with a simplified magnetic circuit model. Furthermore, the electromagnetic characteristics of the proposed machines are investigated and compared by the finite-element method (FEM). The experiments on one prototype are carried out to validate the FEM results.

The effect of temperature and bulking agents, namely sawdust (SD), wheat bran (WB), and wheat straw (WS), on bio-drying of high-solid anaerobically digested sludge (ADS) was evaluated. A mixture of...

When a large amount of wind power is connected to the power grid, certain control methods need to be taken for wind turbines (WTs) so that WTs can respond to system frequency changes and maintain system frequency stability. Based on the frequency control method of a single doubly fed induction generator, a deloading power coordinated distribution method for frequency regulation by wind farms considering wind speed differences is proposed to better utilize the wind farm frequency regulation ability. A reasonable distribution of the deloading power of a wind farm for participation in grid frequency regulation to better utilize the wind farm frequency regulation ability. A quantitative calculation formula for the wind speed, total deloading power and single WT deloading power is established by using a variable parameter deloading power coordinated distribution coefficient based on the wind speed. The deloading power is distributed according to the wind speed of the WT units to adapt to the wind speed distribution differences between WTs in cluster wind farms and fully utilize the wind farm frequency regulation ability. A typical doubly fed induction generator (DFIG) wind farm is used as a simulation case. The experimental results show that the control strategy can distribute the output of each WT, improve the frequency response of the wind farm and enhance the frequency stability of the system.

Hydraulic fracturing has been widely applied to stimulate the natural gas and oil production from unconventional reservoirs. To optimize the design of hydraulic fracturing in this application, an accurate estimation of the initiation and propagation of hydraulic fractures is indispensable. However, it still remains challenging as a result of the complex stress state and geological conditions. On account of their ability to complete control some significant factors and efficient observation of fracture geometry, laboratory-scale hydraulic fracturing experiments have received abundant research attention in recent years. This paper presents a review of the state of the art of laboratory-scale hydraulic fracturing experiments, focusing on the scaling analysis, experimental setup, fracturing fluids, and sample preparation. A discussion of the directions for future research is also provided with the intention of stimulating the development of the experimental technique for investigating hydraulic fracturing.

Geomaterials such as rock mass often have initial damage under the influence of long-term geological action and hydration corrosion environment. The initial damage affects the integrity and stability of the rock mass, resulting in a difference in the mechanical properties of jointed rock mass and intact one. Therefore, the study of the fracture and failure characteristics of the jointed rock mass is of great significance. Most of the previous researches into the fracture behavior of rock with initial damage are based on model testing, theoretical analysis, and numerical simulation of rock mass with preexisting flaws. This review concentrates on the theoretical, experimental, and numerical efforts that have been devoted to the fracture characteristics of rock or rock-like specimens with preexisting flaws under compression. Some suggestions on the future research work in this field are also given.

In the context of wind power connected to the grid, the uncertainty of wind power prediction will lead to inaccurate reactive partition based on voltage reactive sensitivity. A reactive-voltage partitioning method for wind power grid based on interval uncertainty clustering is proposed in this paper. Based on the Jacobian matrix, the full-dimensional sensitivity matrix is obtained by successive recursive method. The strength of electrical coupling relationship among all nodes of the system is reflected by establishing a full-dimensional spatial electrical distance matrix. The concept of interval number is introduced to establish the full-dimensional electrical distance matrix based on interval uncertainty, which replaces the electrical distance matrix with a single value. In order to improve the accuracy of the partitioning algorithm and reduce the computational complexity, the UIDK-means clustering algorithm based on interval uncertainty is used for reactive partitioning. The simulation results of the improved IEEE-39 node system show that compared with the traditional partitioning method, the partitioning method based on interval uncertainty can accurately obtain the reactive partitioning result considering wind power prediction uncertainty. It is conducive to improve the accuracy of day-ahead dispatch.

With the rapid increase of wind power grid-connected capacity, improving wind speed prediction accuracy is increasingly important to reduce wind power fluctuations and to the safe and stable operation of power systems. Due to the fluctuations and randomness of wind speed, traditional prediction methods are difficult to predict wind speed accurately. In this paper, a wind speed prediction model based on Gated Recurrent Unit network is built under the deep learning framework of Google-Tensorflow. The appropriate structure and other hyperparameter of the GRU network model are determined through experiments. The model has two hidden layers. The time series data of wind speed are modeled dynamically, and the network parameters are trained by time reverse error propagation algorithm. The experiment uses the measured wind speed data of a wind farm in Xinjiang Province to verify the simulation results. The results show that the proposed model has higher prediction accuracy than the ARMA model and the LSTM model.

This study was undertaken to research the effects of jute fiber content, fiber length, water content and dry density of reinforced and unreinforced soil on the strength influence mechanism by implementing a series of laboratory tests and analysis. The most efficient fiber reinforcement effects was achieved by means of adding jute fiber with content of 0.6 % and length of 6 mm into expansive soil specimen prepared at maximum dry density and optimum moisture content. The cohesion of reinforced specimens increased first with increasing fiber content and fiber length and then decreased with further increase in fiber content and fiber length. The internal friction angle of reinforced specimens were not affected significantly by fiber content and fiber length. Higher water content reduces the fiber reinforcement effects by means of acting as lubricant in the interface of fiber and soil particles. Fiber reinforcement effects is more prominent for specimens prepared at higher dry density by increasing the effective contact area of fiber/soil. The application prospect of soil reinforcement using natural fiber is impeded by the hydrophilic nature and biodegradability of natural fiber, thus, studies on using chemical additive to do surface treatment for natural fiber are needed to improve the interfacial interaction of fiber/soil so as to widen the application of natural fiber.

The household items delivery robot is a multi-functional robot mainly facing the delivery and handling of household goods. It can handle a variety of items while delivering them, such as cup cleaning and fruit cutting. It achieves the grabbing and delivery of various items through multi-degree of freedom robotic arms and claw-changing devices. Its versatile internal structure enables clean cups, cut fruit and transport items. The multi-functional robot as mainly household goods delivery service will make people living feeling standards having a greater improvement and bring great convenience to home living.

The permutation test is an often used test procedure in brain imaging. Unfortunately, generating every possible permutation for large-scale brain image datasets such as HCP and ADNI with hundreds images is not practical. Many previous attempts at speeding up the permutation test rely on various approximation strategies such as estimating the tail distribution with known parametric distributions. In this study, we show how to rapidly accelerate the permutation test without any type of approximate strategies by exploiting the underlying algebraic structure of the permutation group. The method is applied to large number of MRIs in two applications: (1) localizing the male and female differences and (2) localizing the regions of high genetic heritability in the sulcal and gyral pattern of the human cortical brain.

Shuttlecock ball is a popular sport in modern society which including entertainment, skills, mass, fitness, popularity and education. The current status artificial ball picking during the training and sports of the shuttlecock sports was reviewed in this paper. Based on the main structure and working principle of the picking robot, it was designed and presented here. It is designed by the three-dimensional CAD software. Through motion simulation analysis, the actual working process of the shuttlecock collection robot was shown. The structure design and motion simulation analysis of the whole machine were carried out and it verified the feasibility of the design. The shuttlecock collection robot is used of retrieving, sorting and placing the shuttlecock. It could effectively solve the inconvenience cause by the manual collecting in shuttlecock ball sports.

Manual sampling can easily lead to lack of representativeness and cause quality disputes. Combining with the actual situation of Rizhao Port, the paper discussed the necessity and advantages of removable mechanical sampling equipment for iron ore sampling.the deviation and water loss of the system are compared experimentally and the sampling equipment meets the standard requirements.

Rock engineering especially deep rock engineering undergoing long-term effects of external loading and gravity all or most may gradually damage deformation or creep deformation accumulation, leading rock structures to damage, crack, such as severe plastic deformation or even progressive failure. In this paper, based on the nonlinear damage creep characteristics of rock and damage variable, a new nonlinear damage creep constitutive model of high-stress soft rock is defined in series with the improved Burgers model, Hooke model and St. Venant model. This new nonlinear damage creep constitutive model can work out fairly reasonably explanations for the soft rock creep deformation. A series of uniaxial compression creep tests were performed to study the creep damage characteristics of typical soft rock in Jinchuan No.2 Mine in the northwest of China. Using the increment step loading and single-step loading, the results of creep experiments and nonlinear damage creep constitutive model results are very consistent in this study. The new model not only can reflect the whole course of creep deformation, but also can reasonably describe the soft rock under different initial creep stage, steady-state creep stage and accelerated creep stage. Therefore, the new nonlinear creep damage model is a reasonable reference model for the research of soft rock creep.

Five nearly E-W-trending alkali-rich igneous rock belts are distributed from north to south in northern Xinjiang, and they are composed mainly of riebeckite, K-feldspar granite and high-K and medium-K calc-alkaline volcanic rocks and shoshonite. They were mainly emplaced or erupted between the Carboniferous and Permian. The compositions of Sr, Nd, Pb, and O isotopes imply that their principal resource materials are derived from the upper mantle or juvenile crust, indicating obvious continental growth in the Phanerozoic. The trace element association implies that their tectonic settings are within plate and volcanic arc for alkali-rich granites, and post-collisional arc, late oceanic arc and continental arc for alkali-rich volcanic rocks. An archipelago model was suggested for the tectonic evolution in northern Xinjiang. It can be named the central-Asia-type orogeny, which is different from the so called circum-Pacific ocean-continent-type tectonics or the Alpine-Himalayan continent-continent-collisional orogeny.

In intermediate-acid magmatic rocks, alkaline magmatic rocks, gneisses and migmatitic rocks K-feldspar is a rock-forming rock in which the contents of Pb are highest, just 2 –10 times those of the whole rock,3–16 times those of mica minerals and 6–32 times those of quartz. The lowest contents of K-feldspar are recognized in Early Proterozoic and Achaean rocks, with Pb in the K-feldspar accounting for less than 10% of that in the whole rock; in post-Middle Proterozoic alkaline magmatic rocks, K-feldspar-rich granites and metamorphic rocks the contents of K-feldspar tend to increase, with the proportion of Pb over that in the whole rock being obviously increased. In the alkaline rocks in which K-feldspar accounts for 50% –70% of the total in the whole rock, the contents of Pb in K-feldspar account approximately for 70% –95% of the total lead in the whole rock. Being accessible to hydrothermal alteration in the late periods, K-feldspar was conversed to sericite, calcite, quartz, etc. In the process of such conversion the lead would be leached out and then find its way into fluid phase. This kind of transformation can provide sufficient ore-forming material for later Pb metallogenesis.

Based on the mineral and chemical compositions of spoils taken from the Shilu Cu-Mo deposit and Hetai gold deposit, the leaching and batch experiments were made on spoils taken from these two deposits using the leaching column designed by the authors. The experimental results showed that it is not always true that the mine drainage is acidic. Its acidity depends on acid-buffering capacity of gangue, host rock and its alteration mineral assemblage. The composition of the drainage water is related with the interaction between superficial or underground water and solid materials in the spoils, including minerals, hydroxides and amorphous substances. The leaching extent of the element is related with its occurrence form in the deposit. The preferential flow results in leaching-out of heavy metals in large amounts. So it is important to prevent the generating of preferential flow in the system. The results will provide very important grounds for the comprehensive management of land and ecological rehabilitation of the mine site.

Proterozoic granitoid rocks in Zhejiang Province were formed in the Shengongian period (1.8–1.9 Ga) and the Late Jinningian period (0.6–0.9 Ga), respectively. Petrogenetic problems are discussed based on chemical (major, trace elements and REEs) and Nd-Sr isotopic compositions. The Shengongian granites resulted from partial melting of the Badu Group and the Late Jinningian granites are of mantle derivation with or without contamination of crustal material. The crust in Zhejiang had undergone three major periods of growth during 2.6–2.7 Ga, 0.8–1.1 Ga and 0.10–0.12 Ga after it was generated in Archean time. Compositional fractionation in the process of crust evolution is not evident. The presence of Late Jinningian granites of mantle and mantle-crust-derivation along the Jiangshan-Shaoxing Fault is indicative of crust subduction at that time.

The Phanerozoic granitoid rocks include the Caledonian, Indosinian and Yenshanian granitoid rocks. The existence of Caledonian and Indosinian granites was evidenced by zircon U-Pb ages. The study of the characteristics of major, trace and rare-earth elements, isotopic composition and petrogenesis for the granitoid rocks has been made. The Caledonian and Indosinian granites were derived from partial melting of the Proterozoic basement rocks and the two tectonic activities were weak. The Yenshanian granitoid rocks were derived from mixing of mantle and crustal materials. It implies that the crustal accretion took place in Mesozoic time.

The crude alkaloid of Fritillaria ebeiensis G. D. Yu et G. Q. Ji, administrated orally at a given dose, showed strong antitumour activity in inhibiting the growth of the solid type of hepatoma in mice. Chemical studies revealed that the active principles in this crude drug were verticine, verticinone and ebeiedine obtained from this species for the first time. This paper deals with the isolation and activity of these principles.

Rare-earth elements in samples of geological interest were separated from other elements and concentrated onto ion-exchange membrane through ion-exchange procedures. The membrane was then used to determine the REE by X-ray fluorescence spectrography. In comparison with the traditional “thick-specimen” approach, the requirement of sample (REE oxides) in this method was reduced from 10 to 1 mg. Variable-internal-standard-quantification method was adopted to determine the relative concentrations of REE collected on the membrane. The area density of the sample was controlled at about 0.0003 g/cm2, so that the matrix effect could be eliminated to a satisfactory extent. Interference calibration between the spectro-lines and the background determination was also improved, with the detection limit reaching 2.5×10−6g.

REE contents in whole-rock samples and constituent minerals of the Qianlishan and Baerzhe granites from China were determined using three analytical methods (ICP-AES, ICP-MS, and ID-TIMS). The REE abundance patterns of the granites show the M-type tetrad effect and strong Eu depletion in both wholerock samples and in individual minerals samples. Fluid-melt interaction in the late stage of fractional crystallization is suggested to be the most important factor controlling the formation of REE tetrad effects in the granites.

Copyright © 2015 Bingxiang Yuan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., Two scale-model tests were separately conducted in standard Toyoura sand with relative density of 50% and 80%. The effect of sand relative density on pile-soil interaction was investigated through the response of a laterally loaded pile and the sand movement around the pile. At a displacement of 3.6 mm of the loading point, the applied loads in loose and dense sand were 4.775 N and 21.025 N, respectively, and the maximum moment and soil resistance of the pile in dense sand were over 4 times those in loose sand. However, the deflection of the pile in dense sand was less than that in loose sand; additionally, the depth of zero deflection in dense sand was also less than that in loose sand. At the same time, the maximum displacements of loose sand in the vertical profile and ground surface were over 1.5 times those of dense sand. These characteristics occurred because the relative stiffness ratio of soil and pile increased as the relative density increased, which caused the behavior of the pile in dense sand to be elastic rather than rigid. In addition, the compacted sand particles did not move as easily as the loose sand particles.