mlsa-iai-msu-lab/ru_sci_bench_zho_cite_reranking huggingface dataset:
Geotechnical characterization of red shale and its indication for ground control in deep underground mining

Geotechnical properties of red shale encountered in deep underground mining were characterized on both laboratory and field scale to reveal its unfavorably in geoenvironment. Its constituents, microstructure, strength properties and water-weakening properties were investigated. In situ stress environment and mining-induced fractured damage zone after excavation were studied to reveal the instability mechanism. The results show that red shale contains swelling and loose clayey minerals as interstitial filling material, producing low shear strength of microstructure and making it vulnerable to water. Macroscopically, a U-shaped curve of uniaxial compressive strength (UCS) exists with the increase of the angle between macro weakness plane and the horizon. However, its tensile strength reduced monotonically with this angle. While immersed in water for 72 h, its UCS reduced by 91.9% comparing to the natural state. Field sonic tests reveal that an asymmetrical geometrical profile of fractured damage zone of gateroad was identified due to geological bedding plane and detailed gateroad layout with regards to the direction of major principle stress. Therefore, red shale is a kind of engineering soft rock. For ground control in underground mining or similar applications, water inflow within several hours of excavation must strictly be prevented and energy adsorbing rock bolt is recommended, especially in large deformation part of gateroad.
A new procedure for determining dry density of mixed soil containing oversize gravel

This paper presents a novel computational procedure for the maximum dry density of mixed soils containing oversize particles. At first, the large-scale compaction test data for mixed soils are analyzed by an artificial neural network to determine the main factors affecting the compaction. These factors are then imposed on a genetic programming method and a new mathematical equation emerges. The new equation has more conformity with the experimental data in comparison with the previous correction methods. Besides, the mixed soil dry density is associated with most base soil and oversize fraction specifications. With regard to the sensitivity analyses, if the mixed soil contains high percentages of oversize fraction, the mixed soil composition is governed by the specification of oversized grains, such as specific gravity and the maximum grain size and by increasing these factors, the mixed soil dry density is increased. In mixed soil with a low content of oversize, the base soil specification mainly controls the compaction behavior of mixed soil. Furthermore, if the base soil is inherently compacted with greater dry density, adding the oversize slightly improves the mixed soil dry density. In contrast, adding oversized grains to the base soil with a lower dry density produces a mixed soil with greater dry density. By increasing the maximum grain size difference between the oversize fraction and base soil, the dry density of mixed soil is enhanced.
Bidirectional secondary transmissions with energy harvesting in cognitive wireless sensor networks

To the existing spectrum sharing schemes in wireless-powered cognitive wireless sensor networks, the protocols are limited to either separate the primary and the secondary transmission or allow the secondary user to transmit signals in a time slot when it forwards the primary signal. In order to address this limitation, a novel cooperative spectrum sharing scheme is proposed, where the secondary transmission is multiplexed with both the primary transmission and the relay transmission. Specifically, the process of transmission is on a three-phase time-switching relaying basis. In the first phase, a cognitive sensor node SU_1 scavenges energy from the primary transmission. In the second phase, another sensor node SU_2 and primary transmitter simultaneously transmit signals to the SU_1. In the third phase, the node SU_1 can assist the primary transmission to acquire the opportunity of spectrum sharing. Joint decoding and interference cancellation technique is adopted at the receivers to retrieve the desired signals. We further derive the closed-form expressions for the outage probabilities of both the primary and secondary systems. Moreover, we address optimization of energy harvesting duration and power allocation coefficient strategy under performance criteria. An effective algorithm is then presented to solve the optimization problem. Simulation results demonstrate that with the optimized solutions, the sensor nodes with the proposed cooperative spectrum sharing scheme can utilize the spectrum in a more efficient manner without deteriorating the performance of the primary transmission, as compared with the existing one-directional scheme in the literature.
Thermal damage constitutive model for rock considering damage threshold and residual strength

With the gradual depletion of mineral resources in the shallow part of the earth, resource exploitation continues to move deeper into the earth, it becomes a hot topic to simulate the whole process of rock strain softening, deformation and failure in deep environment, especially under high temperature and high pressure. On the basis of Lemaitre’s strain-equivalent principle, combined with statistics and damage theory, a statistical constitutive model of rock thermal damage under triaxial compression condition is established. At the same time, taking into account the existing damage model is difficult to reflect residual strength after rock failure, the residual strength is considered in this paper by introducing correction factor of damage variable, the model rationality is also verified by experiments. Analysis of results indicates that the damage evolution curve reflects the whole process of rock micro-cracks enclosure, initiation, expansion, penetration, and the formation of macro-cracks under coupled effect of temperature and confining pressure. Rock thermal damage shows logistic growth function with the increase of temperature. Under the same strain condition, rock total damage decreases with the rise of confining pressure. By studying the electron microscope images (SEM) of rock fracture, it is inferred that 35.40 MPa is the critical confining pressure of brittle to plastic transition for this granite. The model parameter F reflects the average strength of rock, and M reflects the morphological characteristics of rock stress–strain curves. The physical meanings of model parameters are clear and the model is suitable for complex stress states, which provides valuable references for the study of rock deformation and stability in deep engineering.
Effect of capacitance on ZnO-Bi_2O_3-Yb_2O_3 based varistor for nanosecond transients

The microstructure and electrical properties of ZnO-Bi_2O_3-Yb_2O_3 based varistor ceramics were investigated with various temperature effects from 900 °C to 1050 °C. From the results, it was observed that the increase of sintering temperature offers a reduced capacitive effect from 0.460 nF to 0.321 nF. Furthermore, the grain sizes of varistors were varied from 6.8 μm to 9.8 μm. The consequence of such smaller grain sizes provided a better voltage gradient of about 895 V/mm for the disc sintered at 900 °C and fallen drastically to 410 V/mm for the sample sintered at 1050 °C. In addition, there was an increase of non-linearity index to a maximum value of 36.0 and reduced leakage current of 0.026 mA/cm~2. However, the density of the varistor decreased with an increase of temperature from 5.41 g/cm~3 to 5.24 g/cm~3. With this base, the influence of varistor capacitance and high voltage gradient were scrutinized and it led an improved transition speed of the varistor assembly from non-conduction to conduction mode during intruding nanosecond transients.
Upper bound analysis of ultimate pullout capacity of shallow 3-D circular plate anchors based on nonlinear Mohr-Coulomb failure criterion

Based on the nonlinear Mohr-Coulomb failure criterion and the associated flow rules, the three-dimensional (3-D) axisymmetric failure mechanism of shallow horizontal circular plate anchors that are subjected to the ultimate pullout capacity (UPC) is determined. A derivative function of the projection function for projecting the 3-D axisymmetric failure surface on plane is deduced using the variation theory. By using difference principle, the primitive function of failure surface satisfying boundary condition and numerical solution to its corresponding ultimate pullout capacity function are obtained. The influences of nonlinear Mohr-Coulomb parameters on UPC and failure mechanism are studied. The result shows that UPC decreases with dimensionless parameter m and uniaxial tensile strength increases but increases when depth and radius of plate anchor, surface overload, initial cohesion, geomaterial density and friction angle increase. The failure surface is similar to a symmetrical spatial funnel, and its shape is mainly determined by dimensionless parameter m; the surface damage range expands with the increase of radius and depth of the plate anchor as well as initial cohesion but decreases with the increase of dimensionless parameter m and uniaxial tensile strength as well as geomaterial density. As the dimensionless parameter m=2.0, the numerical solution of UPC based on the difference principle is proved to be feasible and effective through the comparison with the exact solution. In addition, the comparison between solutions of UPC computed by variation method and those computed by upper bound method indicate that variation method outperforms upper bound method.
Benzohydroxamic acid to improve iron removal from potash feldspar ores

The technological mineralogy of the potash feldspar was investigated and a new collector named Yb105 was adopted to remove iron from potash feldspar ores. The technological mineralogy results indicate that the main components of the ore were feldspar, sericite, quartz and kaolinite, and iron mainly existed in limonite and hematite, most of which can be removed by beneficiation. The results show the benzohydroxamic acid can not only increase the recovery of iron and reduce the consumption of oleic acid collector, but also enhance the collecting performance of oleic acid at low temperature, which can realize the flotation of the ores at a low temperature and play an important role in saving energy to some extent. Compared with oleic oil, the benzohydroxamic acid had a great advantage in removing iron from potash feldspar, a potash feldspar concentrate with Fe grade of 0.23%, K_2O grade of 12.59% and Na_2O grade of 0.26% was obtained by flotation with Yb105 as collector, and the yield of the concentrate was 82.55%.
Cooperative driving model for non-signalized intersections with cooperative games

Cooperative driving around intersections has aroused increasing interest in the last five years. Meanwhile, driving safety in non-signalized intersections has become an issue that has attracted attention globally. In view of the potential collision risk when more than three vehicles approach a non-signalized intersection from different directions, we propose a driving model using cooperative game theory. First, the characteristic functions of this model are primarily established on each vehicle’s profit function and include safety, rapidity and comfort indicators. Second, the Shapley theorem is adopted, and its group rationality, individual rationality, and uniqueness are proved to be suitable for the characteristic functions of the model. Following this, different drivers’ characteristics are considered. In order to simplify the calculation process, a zero-mean normalization method is introduced. In addition, a genetic algorithm method is adopted to search an optimal strategy set in the constrained multi-objective optimization problem. Finally, the model is confirmed as valid after simulation with a series of initial conditions.
Numerical and experimental investigation of rock breaking method under free surface by TBM disc cutter

To study the rock breaking method under the free surface induced by disc cutter, the rock breaking simulations were first conducted based on the discrete element method, and the dynamic process of rock breaking under the free surface was studied including stressed zone, crush zone, crack initiation and propagation. Then the crack propagation conditions, specific energy, etc. under different free surface distance (S) were also investigated combined with linear cutting experiments. The results show that the rock breaking process under the free surface induced by disc cutter is dominated by tension failure mode. There exists a critical S to promote crack propagation to free surface effectively. And this rock breaking method can improve the rock breaking force and breaking efficiency significantly when proper.
Study of road tunnel threshold zone lighting reduction coefficient

The luminance in the road tunnel threshold zone attracts broad attention due to its enormous energy consumption and direct influence on tunnel transportation security. Current lighting design methods in threshold zones mostly adopt the reduction coefficient method. However, the determination of reduction coefficient k simply considers tunnel design speed and flow rate, while excluding outside tunnel luminance and threshold zone color temperature and luminance, which have a major impact on driver visual adaptation. Existing problems in the determination of k value are analyzed; a visual performance experiment is utilized; and the reaction time of drivers in changeable outside tunnel luminance and threshold zone color temperature and luminance conditions is obtained; thus, the equations concerning reduction coefficient variation law are derived. In the end, a comparative analysis is made of the k values of the reduction coefficient stipulated by various norms under different color temperature conditions.
Determination of trace impurity elements in MnZn ferrite powder by direct current glow discharge mass spectrometry

An analytical method for the determination of 26 impurity elements (such as Li, Be, Na, Mg, Al, Si, P, S, K, Ca, Sc, Ti, V, Cr, Co, Ni, Ga, Ge, Y, Nb, Mo, Ag, Cd, Sb, W and Pb) in MnZn ferrite powder by direct current glow discharge mass spectrometry (GD-MS) was established. MnZn ferrite powder was mixed with copper powder, used as a conductor, and pressed. The effects of MnZn ferrite powder preparation conditions and glow discharge parameters for the sensitivity and stability of signal analysis were investigated. By determining the choice of isotope and the application of the mass resolutions of 4000 (MR, medium resolution) and 10000 (HR, high resolution), mass spectral interference was eliminated. The contents of impurity elements in MnZn ferrite powder was calculated by subtraction after normalizing the total signal of Mn, Zn, Fe, O and Cu. The results showed that the detection limit of 26 kinds of impurity elements was between 0.002 and 0.57 μg/g, and the relative standard deviation (RSD) was between 3.33% and 32.35%. The accuracy of this method was verified by the ICP-MS. The method was simple and practical, which is applied to the determination of impurity elements in MnZn ferrite powder.
Optimized algorithm in mine production planning,mined material destination,and ultimate pit limit

An integral connection exists among the mine production planning,the mined material destination,and the ultimate pit limit (UPL) in the mining engineering economy.This relation is reinforced by real information and the benefits it engenders in the mining economy.Hence,it is important to create optimizing algorithms to reduce the errors of economic calculations.In this work,a logical mathematical algorithm that considers the important designing parameters and the mining economy is proposed.This algorithm creates an optimizing repetitive process among different designing constituents and directs them into the maximum amount of the mine economical parameters.This process will produce the highest amount of ores and the highest degree of safety.The modeling produces a new relation between the concept of the cutoff grade,mine designing,and mine planning,and it provides the maximum benefit by calculating the destination of the ores.The proposed algorithm is evaluated in a real case study.The results show that the net present value of the mine production is increased by 3% compared to previous methods of production design and UPL.
Ground stability of underground gateroad with 1 km burial depth:A case study from Xingdong coal mine,China

This paper presents an integrated investigation of the ground stability of a deep gateroad with a 1 km burial depth based on a field test,case studies,and numerical modelling.In situ stress measurements and mechanical properties tests were first conducted in the test site.Then,the deformation behavior,stress and yield zone distributions,as well as the bolts load of the gateroad,were simulated using FLAC~(3D) software.The model results demonstrated that the soft rock properties and high in situ stress were the main factors for the deep gateroad instability,and the shear slip failure induced by the high stress was the primary failure model for the deep rock mass.In addition,the unsuitable support patterns,especially the relatively short bolts/cables with low pre-tensions,the lack of high-strengthen secondary supports and the unsupported floor strata,also contributed to the gateroad instability.Subsequently,a new combined supporting strategy,incorporating longer bolts/cables,yielding ring supports,and grouting measures,was proposed for the deep gateroad,and its validity was verified via field monitoring.All these could be a reference for understanding the failure mechanism of the gateroad with 1 km burial depth.
Hydration film measurement on mica and coal surfaces using atomic force microscopy and interfacial interactions

The hydration film on particle surface plays an important role in bubble-particle adhesion in mineral flotation process.The thicknesses of the hydration films on natural hydrophobic coal and hydrophilic mica surfaces were measured directly by atomic force microscopy (AFM) based on the bending mode of the nominal constant compliance regime in AFM force curve in the present study.Surface and solid–liquid interfacial energies were calculated to explain the forming mechanism of the hydration film and atomic force microscopy data.The results show that there are significant differences in the structure and thickness of hydration films on coal and mica surfaces.Hydration film formed on mica surface with the thickness of 22.5 nm.In contrast,the bend was not detected in the nominal constant compliance regime.The van der Waals and polar interactions between both mica and coal and water molecules are characterized by an attractive effect,while the polar attractive free energy between water and mica (-87.36 mN/m) is significantly larger than that between water and coal (-32.89 mN/m),which leads to a thicker and firmer hydration layer on the mica surface.The interfacial interaction free energy of the coal/water/bubble is greater than that of mica.The polar attractive force is large enough to overcome the repulsive van der Waals force and the low energy barrier of film rupture,achieving coal particle bubble adhesion with a total interfacial free energy of -56.30 mN/m.
Simulation and analysis of humid air turbine cycle based on aeroderivative three-shaft gas turbine

Due to the fact that the turbine outlet temperature of aeroderivative three-shaft gas turbine is low, the conventional combined cycle is not suitable for three-shaft gas turbines. However, the humid air turbine (HAT) cycle provides a new choice for aeroderivative gas turbine because the humidification process does not require high temperature. Existing HAT cycle plants are all based on single-shaft gas turbines due to their simple structures, therefore converting aeroderivative three-shaft gas turbine into HAT cycle still lacks sufficient research. This paper proposes a HAT cycle model on a basis of an aeroderivative three-shaft gas turbine. Detailed HAT cycle modelling of saturator, gas turbine and heat exchanger are carried out based on the modular modeling method. The models are verified by simulations on the aeroderivative three-shaft gas turbine. Simulation results show that the studied gas turbine with original size and characteristics could not reach the original turbine inlet temperature because of the introduction of water. However, the efficiency still increases by 0.16% when the HAT cycle runs at the designed power of the simple cycle. Furthermore, simulations considering turbine modifications show that the efficiency could be significantly improved. The results obtained in the paper can provide reference for design and analysis of HAT cycle based on multi-shaft gas turbine especially the aeroderivative gas turbine.
A compound objective reconfiguration of distribution networks using hierarchical encoded particle swarm optimization

With the development of automation in smart grids, network reconfiguration is becoming a feasible approach for improving the operation of distribution systems. A novel reconfiguration strategy was presented to get the optimal configuration of improving economy of the system, and then identifying the important nodes. In this strategy, the objectives increase the node importance degree and decrease the active power loss subjected to operational constraints. A compound objective function with weight coefficients is formulated to balance the conflict of the objectives. Then a novel quantum particle swarm optimization based on loop switches hierarchical encoded was employed to address the compound objective reconfiguration problem. Its main contribution is the presentation of the hierarchical encoded scheme which is used to generate the population swarm particles of representing only radial connected solutions. Because the candidate solutions are feasible, the search efficiency would improve dramatically during the optimization process without tedious topology verification. To validate the proposed strategy, simulations are carried out on the test systems. The results are compared with other techniques in order to evaluate the performance of the proposed method.
A hybrid algorithm based on tabu search and large neighbourhood search for car sequencing problem

The car sequencing problem (CSP) concerns a production sequence of different types of cars in the mixed-model assembly line. A hybrid algorithm is proposed to find an assembly sequence of CSP with minimum violations. Firstly, the hybrid algorithm is based on the tabu search and large neighborhood search (TLNS), servicing as the framework. Moreover, two components are incorporated into the hybrid algorithm. One is the parallel constructive heuristic (PCH) that is used to construct a set of initial solutions and find some high quality solutions, and the other is the small neighborhood search (SNS) which is designed to improve the new constructed solutions. The computational results show that the proposed hybrid algorithm (PCH+TLNS+SNS) obtains 100 best known values out of 109 public instances, among these 89 instances get their best known values with 100% success rate. By comparing with the well-known related algorithms, computational results demonstrate the effectiveness, efficiency and robustness of the proposed algorithm.
早竹林拉步甲成虫种群动态和对金针虫的捕食作用

【目的】为了明确3种不同类型早竹Phyllostachys praecox林地拉步甲Carabus lafossei成虫的种群动态和对金针虫的捕食作用。【方法】采用陷阱法诱捕步甲成虫,采用形态学结合DNA条码法进行物种鉴定;分析拉步甲数量与土壤化学性质和林下植被盖度之间的相关性;质量测定法计算拉步甲对竹林金针虫的捕食量。【结果】 3种类型早竹林中共捕捉到拉步甲成虫188头,其中撂荒地136头,中等强度经营样地34头,高强度经营样地18头。早竹林拉步甲成虫在4-10月份均有分布,其中以4-5月份种群数量最大。拉步甲个体数量与林下植被盖度极显著的正相关,与全磷和水解性氮极显著性的负相关,与有效磷显著的负相关。捕食量分析表明,单头的最大捕食量为0.734 g,最小捕食量为0.390 g,平均捕食量为0.540 g。【结论】早竹林拉步甲成虫的种群数量大、存活时间长,其种群数量在不同经营方式样地之间存在极显著差异;拉步甲能够捕食竹林金针虫,是竹林金针虫的捕食性天敌昆虫。