Nine phyto-ashes from the biomass combustion of birch (Betula), oak (Quercus), red oak (Quercus rubra), horbeam (Carpinus), pine (Pinus sylvestris), poplar (Populus), maple (Acer), oilseed rape straw (Brassica napus) and wheat straw (Triticum aestivum) were blended with a biogas digestate at 1:1 mass ratio to give nine organic-mineral soil improvers. The concept of the research was to outline an eco-friendly and low cost soil improver for remediating degraded lands. These (i.e. phyto-ashes, improvers and the biogas digestate) were applied (0, 5, 10, 20, 40 t·ha-1) to a soil metallurgically contaminated with Cu, Zn, Pb and Cd. Of several tested parameters, pH changes revealed that organic-mineral soil improvers may efficiently replace (linear R2>0.90****, P<0.001) phyto-ashes in soil remedial goals. Buffering properties expressed by the cation exchange capacity (CEC) improved progressively: 29, 52, 71, 100% (phyto-ash treatments) and: 18, 37, 44, 73% (improvers treatments) for the rates 5, 10, 20, 40 t·ha-1, respectively as referred to the control CEC. The Dynamic Remediation Efficiency (DRE) indices for Cu, Zn, Pb, Cd revealed metal-specific geochemical reactions initiated by phyto-ashes, improvers and biogas digestate. The rates 5.0–10.0 t·ha-1 for phyto-ashes and about 20 t·ha-1 for improvers [1:1, i.e. Phyto-ash:Biogas digestate] are recommended. For biogas digestate, the rates 10–20 t·ha-1 were found more efficient.
In the present theoretical analysis, the combined effects of slider curvature and non-Newtonian pseudoplastic and dilatant lubricants (lubricant blended with viscosity index improver) on the steady and dynamic characteristics of pivoted curved slider bearings have been investigated for Rabinowitsch fluid model. The modified Reynolds equations have been obtained for steady and damping states of bearing. To solve the modified Reynolds equations, perturbation theory has been adopted. The results for the steady state characteristics (steady state film pressure, load carrying capacity and centre of pressure) and dynamic characteristics (dynamic damping and dynamic stiffness) have been calculated numerically for various values of viscosity index improver using Mathematica. In comparison with the Newtonian lubricants, higher values of film pressure, load carrying capacity, dynamic damping and dynamic stiffness have been obtained for dilatant lubricants, while the case was reversed for pseudoplastic lubricants. Significant variations in the bearing characteristics have been observed for even small values of pseudoplastic parameter, that is, with the non-Newtonian dilatant and pseudoplastic behaviour of the fluid.
There is a general agreement that remembering depends not only on the memory processes as such but rather that encoding, storage and retrieval are under the constant influence of the overarching, metacognitive processes. Moreover, many interventions designed to improve memory refer in fact to metacognition. Most attempts to integrate the very different theoretical and experimental approaches in this domain focus on encoding, whereas there is relatively little integration of approaches that focus on retrieval. Therefore, we reviewed the studies that used new ideas to improve memory retrieval due to a “metacognitive intervention”. We concluded that whereas single experimental manipulations were not likely to increase metacognitive ability, more extensive interventions were. We proposed possible theoretical perspectives, namely the Source Monitoring Framework, as a means to integrate the two, so far separate, ways of thinking about the role of metacognition in retrieval: the model of strategic regulation of memory, and the research on appraisals in autobiographical memory. We identified venues for future research which could address, among other issues, integration of these perspectives.
A transformer is an important part of power transmission and transformation equipment. Once a fault occurs, it may cause a large-scale power outage. The safety of the transformer is related to the safe and stable operation of the power system. Aiming at the problem that the diagnosis result of transformer fault diagnosis method is not ideal and the model is unstable, a transformer fault diagnosis model based on improved particle swarm optimization online sequence extreme learning machine (IPSO-OS-ELM) algorithm is proposed. The improved particle swarmoptimization algorithm is applied to the transformer fault diagnosis model based on the OS-ELM, and the problems of randomly selecting parameters in the hidden layer of the OS-ELM and its network output not stable enough, are solved by optimization. Finally, the effectiveness of the improved fault diagnosis model in improving the accuracy is verified by simulation experiments.
The evolution of microstructured optical fibers with hexagonal array (H-MOFs) of air-holes rooted in the background of undoped silica has led to the realization of an ideal host for encouraging and technologically entitled optical properties. We focus to explore the divergence of radiation into free space from the end-facet of solid-core H-MOFs by using the improved theoretical model. Also, we investigated the wavelength dependence of beam divergence angle for principal core mode of H-MOFs under step-index fiber approximation (SIFA). Experimental results have been included for comparison.
Coordinate Measurement Machines (CMMs) have been extensively used in inspecting mechanical parts with higher accuracy. In order to enhance the efficiency and precision of the measurement of aviation engine blades, a sampling method of profile measurement of aviation engine blade based on the firefly algorithm is researched. Then, by comparing with the equal arc-length sampling algorithm (EAS) and the equi-parametric sampling algorithm (EPS) in one simulation, the proposed sampling algorithm shows its better sampling quality than the other two algorithms. Finally, the effectiveness of the algorithm is verified by an experimental example of blade profile. Both simulated and experimental results show that the method proposed in this paper can ensure the measurement accuracy by measuring a smaller number of points.
The article presents an analysis of the multi-operation hot die forging process, performed on a press, of producing a lever forging used in the motorcycles of a renowned producer by means of numerical simulations. The investigations were carried out in order to improve (perfect) the currently applied production technology, mainly due to the presence of forging defects during the industrial production process. The defects result mainly from the complicated shape of the forging (bent main axis, deep and thin protrusions, high surface diversity in the cross section along the length of the detail), which, during the filling of the die by the deformed material, causes the presence of laps, wraps and underfills on the forging. Through the determination of the key parameters/quantities during the forging process, which are difficult to establish directly during the industrial process or experimentally, a detailed and complex analysis was performed with the use of FEM as well as through microstructure examinations. The results of the performed numerical modelling made it possible to determine: the manner of the material flow and the correctness of the impression filling, as well as the distributions of temperature fields and plastic deformations in the forging, and also to detect the forging defects often observed in the industrial process. On this basis, changes into the process were introduced, making it possible to improve the currently realized technology and obtain forgings of the proper quality as well as shape and dimensions.
Scientists around the world agree that nowadays, science is facing severe challenges like poor peer-review system, replicability crisis, or locked science behind paywalls. The National Science Center addresses at least some of them by introducing procedures that promote integrity, ethics, social responsibility, transparency, and openness in science.
The smart grid concept is predicated upon the pervasive With the construction and development of distribution automation, distributed power supply needs to be comprehensively considered in reactive power optimization as a supplement to reactive power. The traditional reactive power optimization of a distribution network cannot meet the requirements of an active distribution network (ADN), so the Improved Grey Wolf Optimizer (IGWO) is proposed to solve the reactive power optimization problem of the ADN, which can improve the convergence speed of the conventional GWO by changing the level of exploration and development. In addition, a weighted distance strategy is employed in the proposed IGWO to overcome the shortcomings of the conventional GWO. Aiming at the problem that reactive power optimization of an ADN is non-linear and non-convex optimization, a convex model of reactive power optimization of the ADN is proposed, and tested on IEEE33 nodes and IEEE69 nodes, which verifies the effectiveness of the proposed model. Finally, the experimental results verify that the proposed IGWO runs faster and converges more accurately than the GWO.
[1] Liang X.D., Gao Y.F., Wang J.F. et al., Rapid development of silicone rubber composite insulators in China, High Voltage Engineering, vol. 42, no. 9, pp. 2888–2896 (2016), DOI: 10.13336/j.1003- 6520.hve.20160907025.
[2] Yuan Z.K., Degradation characteristics and mechanism of materials in composite insulator under high humidity, PhD Thesis, North China Electric Power University, Beijing (2019).
[3] Xoa Y.F., Song X.M., He J.Z. et al., Evaluation method of aging for silicone rubber of compos- ite insulator, Transactions of China Electrotechnical Society, vol. 34, no. S1, pp. 440–448 (2019), DOI: 10.19595/j.cnki.10006753.tces.L80647.
[4] Tang J., Liu Q.S., Liu J.W. et al., Evaluation of composite insulators based on fuzzy comprehen- sive evaluation, Engineering Journal of Wuhan University, vol. 52, no. 5, pp. 451–456 (2019), DOI: 10.14188/j.1671-8844.2019-05-012.
[5] Huang X., Wang L.Y., Wang Q. et al., Grey fuzzy comprehensive evaluation model of contamina- tion state for insulators based on IFAHP with bayesian modified method, Science Technology and Engineering, vol. 20, no. 13, pp. 5135–5141 (2020), DOI: CNKI:SUN:KXJS.0.2020-13-018.
[6] Liu Y.P., Xu Z.Q., Fu H.C. et al., Insulation Condition Assessment Method of Power Transformer Based on Improved Extension Cloud Theory With Optimal Cloud Entropy, High Voltage Engineering, vol. 46, no. 2, pp. 397–405 (2020), DOI: 10.13336/j.1003-6520.hve.20190215004.
[7] Fan L., Xia F., Su H.Y. et al., Risk assessment of high voltage insulator contamination condition by cloud theory, Power System Protection and Control, vol. 40, no. 15, pp. 57–62 (2012), DOI: CNKI: SUN:JDQW.0.2012-15-014.
[8] Wang S.H., Jing H., Study on method for predicting pollution Flashover insulators in contact network, Journal of the China Railway Society, vol. 40, no. 3, pp. 58–67 (2018), DOI: CNKI:SUN:TDXB.0.2018- 03-011.
[9] Huai M.Q., Research on prediction of contamination state of insulator on catenary based on fuzzy neural network, Master Thesis, Lanzhou Jiaotong University, Gansu (2018).
[10] Yang Z.C., Zhang C.L., Ge L. et al., Comprehensive fuzzy evaluation based on entropy weight method for insulator flashover pollution, Electric Power Automation Equipment, vol. 34, no. 4, pp. 90–94 (2014), DOI: CNKI:SUN:DLZS.0.2014-04-016.
[11] Zhou Y.M., Studies on the degradation depth of silicon composite insulator in service, Master Thesis, Wuhan University, Wuhan (2018).
[12] Chen X.C., Li L.Q., Wu Z.G. et al., Research on shed properties of network operating composite insulators, Guangdong Electric Power, vol. 29, no. 6, pp. 104–108 (2016), DOI: 10.3969/j.issn.1007- 290X.2016.06.019.
[13] Yang L.G., Florian Pauli, Kay Hameyer, Influence of thermal-mechanical stress on the insulation system of a low voltage electrical machine, Archives of Electrical Engineering, vol. 70, no. 1, pp. 233–244 (2021), DOI: 10.24425/aee.2021.136064.
[14] Liu Y., Wang J.G., Han F. et al., Electrical and mechanical properties of composite insulators af- ter different operation periods, High Voltage Engineering, vol. 34, no. 5, pp. 1017–1021 (2008), DOI: 10.13336/j.1003-6520.hve.2008.05.027.
[15] Yao L.N., Wu Y.H., Wang S.H. et al., Electrical and mechanical properties of on-line compos- ite insulators, Insulating Materials, vol. 48, no. 8, pp. 23–27 (2015), DOI: 10.16790/j.cnki.1009- 9239.im.2015.08.005.
[16] Jia Z.D., Yang C.X., Wang X.L. et al., Aging characteristics of composite insulators based on hydropho- bicity transfer test, High Voltage Engineering, vol. 41, no. 6, pp. 1907–1914 (2015), DOI: 10.13336/ j.1003-6520.hve.2015.06.019.
[17] Zhang M.M., Research on evaluation Method of Insulator pollution Status Assessment Based on UV Pulse Parameters, Master Thesis, Southwest Jiaotong University, Sichuan (2019).
[18] Mao Y.K., Guan Z.C., Wang L.M. et al., Evaluation of contamination levels of outdoor insulators based on the principal components analysis of leakage current Pulse, Transactions of China Electrotechnical Society, vol. 24, no. 8, pp. 39–45 (2009), DOI: 10.19595/j.cnki.10006753.tces.2009.08.007.
[19] Ning G.T., Fang B., Qin D. et al., Design and application of comprehensive evaluation index system of smart grid based on coordinated planning of major network and power distribution network, Archives of Electrical Engineering, vol. 70, no. 1, pp. 103–113 (2021), DOI: 10.24425/aee.2021.136055.
[20] Zhou L.L., Research of methods and their application of determining the weights of attributes in fuzzy comprehensive evaluation, Master Thesis, Northeastern University, Liaoning (2014).
[21] Li G., Li J.P., Sun X.L. et al., Research on a combined methods of subjective-objective weighting and its rationality, Management Review, vol. 29, no. 12, pp. 17–26+61 (2017), DOI: 10.14120/j.cnki. cn115057/f.2017.12.002.
[22] Chen Y.C., Dai J.Y., Xie D., Comprehensive evaluation of mine ventilation system based on combi- nation weighting cloud model, Systems Engineering, vol. 38, no. 6, pp. 35–42 (2020), DOI: 1001- 4098(2020)06-0035-08.
[23] Wang L.L., Research on cleaner production evaluation index system and grade comprehensive evalua- tion methodologies of wastewater treatment plants in cities and towns, PhD Thesis, Dalian University of Technology, Dalian (2015).