Monitoring of the Variation in Pore Sizes of Woven Geotextiles with Uniaxial Tensile Strain

Characteristic pore-opening size O95 or O90 has been widely used in the filter design of woven geotextiles. These manufactured products have different pore size proportions of large pore diameters, medium pore diameters, and small pore diameters, respectively. Therefore, uncertainties still exist regarding the prediction of geotextile pore diameter variations under the uniaxial tensile strain. This paper investigates the variations in five characteristic pore-opening sizes O95, O80, O50, O30, and O10, with uniaxial tensile strain by using the image analysis method. The large pore diameters, medium pore diameters, and small pore diameters show different variation behaviors as the uniaxial tensile strain increases. Fifteen specific pores are selected and then their pore diameter variations are monitored under each tensile strain of 1%. The colorful pore size distribution diagram is a visual way to identify the variation of pores arranged in the tension direction (warp direction) and the direction perpendicular to tensile loads (weft direction). The various pore diameters are proved to agree well with the bell-shaped Gaussian distribution. The results exhibit an accurate prediction of the variation in large pore sizes, medium pore sizes, and small pore sizes, respectively, for all tested woven geotextiles with uniaxial tensile strain.

A locally Active Discrete Memristor Model and Its Application in a Hyperchaotic Map

The continuous memristor is a popular topic of research in recent years, however, there is rare discussion about the discrete memristor model, especially the locally active discrete memristor model. This paper proposes a locally active discrete memristor model for the first time and proves the three fingerprints characteristics of this model according to the definition of generalized memristor. A novel hyperchaotic map is constructed by coupling the discrete memristor with a two-dimensional generalized square map. The dynamical behaviors are analyzed with attractor phase diagram, bifurcation diagram, Lyapunov exponent spectrum, and dynamic behavior distribution diagram. Numerical simulation analysis shows that there is significant improvement in the hyperchaotic area, the quasi-periodic area and the chaotic complexity of the two-dimensional map when applying the locally active discrete memristor. In addition, antimonotonicity and transient chaos behaviors of system are reported. In particular, the coexisting attractors can be observed in this discrete memristive system, resulting from the different initial values of the memristor. Results of theoretical analysis are well verified with hardware experimental measurements. This paper lays a great foundation for future analysis and engineering application of the discrete memristor and relevant the study of other hyperchaotic maps.

The Influence of Reservoir Composition on the Pore Structure of Continental Shale: A Case Study from the Qingshankou Formation in the Sanzhao Sag of Northern Songliao Basin, NE China

Determining the pore structure characteristics and influencing factors of continental shale reservoir in the oil generation stage is of great significance for evaluating the shale oil reservoir space and analyzing shale oil enrichment mechanism. In this paper, shale from the first member of the Upper Cretaceous Qingshankou Formation (K2qn1) in the Songliao Basin was selected. X-ray diffraction (XRD), Rock-Eval pyrolysis, total organic carbon content (TOC), scanning electron microscopy (SEM), nitrogen gas adsorption (N2GA), and high-pressure mercury injection (HPMI) were used to clarify the composition characteristics of inorganic minerals and organic matter and determine the influencing factors of pore development in the K2qn1 shale. The results show that intergranular pores related to clay minerals and quartz, intragranular dissolution pores related to feldspar, and other mineral intragranular pores are developed. The organic matter pore is less developed, mainly composed of intragranular pores and crack pores of organic matter. Mesopores related to clay minerals are widely developed, rigid quartz particles can protect and support mesopores and macropores, and carbonate cementation can inhibit pore development. Although the TOC contents of shale are commonly less than 2.5%, it has a good positive correlation with porosity; TOC is greater than 2.5%, and the increase of residual oil fills part of the pores, leading to a decrease in porosity with the increase of TOC. Three types (types I, II, and III) of the reservoir space were classified by the combined pore size distribution diagram of N2GA and HPMI. By comparing the characteristics of pore structure parameters, it is found that Type I reservoir space is favorable for shale oil enrichment. It provides scientific guidance for shale oil exploration in the Songliao Basin.

Analytical Study of the Automatic Ventilation System for the Intake of Polluted Air from the Pigsty

The microclimate of a pigsty is determined by the combination of temperature, relative humidity, chemical and mechanical composition of the air, which have a significant impact on animal productivity and must be maintained within strict limits due to the physiological needs and capabilities of animals. An appropriate ventilation system has been created to ensure the removal of air from the pigsty. The purpose of the study is to establish the dependence of the operating parameters of the automatic ventilation system on the air quality in the pigsty, taking into account the permissible concentrations of gases. The developed automatic ventilation system for polluted air intake is located in the middle of the livestock house under the ceiling and consists of a central air duct, to which air intake pipes are connected. Air intake pipes are placed in the middle above each pen where animals are kept. Intake dampers with servomechanisms, temperature, humidity, and air quality sensors are installed at the inlet of the air intake pipes. The outlet of the central air intake duct is connected to the exhaust fan. Intake dampers with servomechanisms and sensors of temperature, humidity, and air quality are connected to the control unit by electrical wires. As a result of analytical studies of the automatic ventilation system for polluted air intake from a pigsty, the conditions for its effective operation have been mathematically substantiated. The developed technique and the algorithm implemented based on the Mathematica software package allows calculating the area of holes that form intake dampers with servomechanisms in the air intake pipes. The distribution of velocities in the air intake pipes and the distribution diagram of the area of holes that form intake dampers with servomechanisms in the air intake pipes are determined taking into account the design and technological parameters of the ventilation system and the distribution of the gas concentration (carbon dioxide, ammonia, and hydrogen sulphide) over the pens

Optical and Structural Characterization of Cd-Free Buffer Layers Fabricated by Chemical Bath Deposition

Chemical bath deposition (CBD) is a suitable, inexpensive, and versatile synthesis technique to fabricate different semiconductors under soft conditions. In this study, we deposited Zn(O;OH)S thin films by the CBD method to analyze the effect of the number of thin film layers on structural and optical properties of buffer layers. Thin films were characterized by X-ray diffraction (XRD) and UV-Vis transmittance measurements. Furthermore, we simulated a species distribution diagram for Zn(O;OH)S film generation during the deposition process. The optical results showed that the number of layers determined the optical transmittance of buffer layers, and that the transmittance reduced from 90% (with one layer) to 50% (with four layers) at the visible range of the electromagnetic spectrum. The structural characterization indicated that the coatings were polycrystalline (α-ZnS and β-Zn(OH)2 to four layers). Our results suggest that Zn(O;OH)S thin films could be used as buffer layers to replace CdS thin films as an optical window in thin-film solar cells.

Simulation of electrothermal characteristics of MEMS energy changer under different current excitation

The simulation model of MEMS energy changer is established by using the finite element analysis software ANSYS. The electrothermal performance of MEMS energy changer under the action of different currents was simulated and analyzed. The bridge area is made of NiCr, and the shape of the bridge area is two different chamfering rectangles. The temperature distribution diagram of MEMS energy changers, the temperature change curve and the phase transition distribution diagram of the bridge region were obtained when the four current values acted on each other. The simulation results are analyzed and discussed.

ELECTROCHEMICAL OBTAINING AND MORPHOLOGY OF ALLOYS’ NANOCOVERINGS IN SYSTEM Re-Сu-Se

Electrochemical obtaining of nano-coatings in the system Re-Cu-Se on platinum electrode during voltammetric cycling was studied. The research was carried out using sulphate solution containing selenium dioxide, potassium perrenate and copper chloride. For obtaining nano coatings in the Re-Cu-Se system, we used an electrolyte of the following composition (mol/l): 6.9 ∙ 10-4 – 6.9 ∙ 10-3 KReO4 + 9 ∙ 10-4 – 1.8 ∙ 10-2 SeO2 + 6 ∙ 10-4 – 1.2 ∙ 10-2 CuCl2 ∙ 2H2O +2 H2SO4, t = 80 ºC; V = 0.005VS-1; pH = 0.1, electrode - Pt. Based on the studying of the volt-ampere dependences during the joint electroreduction of rhenium (VII), selenium (IV) and copper (II) ions from sulfate electrolytes on a PT electrode, the conditions for the deposition of alloys nanocoatings in the Re-Cu-Se system were established. To study the morphology of films on platinum and copper substrates, the electrode surface was studied using a JEOL JSM7600F scanning electron microscope at various magnifications, and was accordingly subjected to elemental analysis using an Oxford X-MAX 50 detector. The sample has been scanned in the mode of secondary electrons at an accelerating voltage ~ 15 keV. It has been found that agglomerates are observed on the electrode surface, mainly consisting of sphere-shaped particles with an average size of ~ 20-25 nm. The spectrum of characteristic X-ray radiation indicates the presence of these components of the system, allows quantitative analysis of samples. Based on the presented distribution diagram by weight percent, the content of system components is represented by the following ratio: Re-12%, Cu-5%, Se-10%. The presence of characteristic peaks of carbon and oxygen in the spectrum is explained by residual phenomena during obtaining.

THE DYNAMIC FREQUENCIES AND SHAPES OF VIBRATIONS RESEARCH OF THE DAM OF THE CHIRKEYSKAYA HPP

The purpose of the research is to monitor the amplitude-frequency characteristics on the example of the Chirkeyskaya HPP dam for further assessment of the state of hydraulic structures and hydroelectric units of the HPP, as well as to develop an automated system for seismometric control of hydraulic structures of the Chirkeyskaya HPP. The article presents the results of modeling and calculations of dynamic test data of the Chirkeyskaya HPP dam using the primary processing of measurement results to identify the quality of information processing by existing methods. The paper presents the results of measurements to create a mathematical model of the dam of the Chirkeyskaya HPP. Methods were used based on the study of the statistical characteristics of vibrations arising under the infl uence of the dynamic effects of equipment and the external environment for the experimental determination of the frequencies and modes of natural vibrations of the hydraulic structures of the Chirkeyskaya HPP. Spatial-frequency diagrams of the vibration intensity distribution in the radial direction were constructed, an algorithm was implemented to use data for both reference points when identifying natural frequencies and dam shapes, a spatial-frequency distribution diagram was constructed, averaged over two reference points, smoothed interpolated along the dam with a uniform step the conversion factor at the ridge level.

Electromagnetic piezoelectric hybrid driven multi-DOF motor contact model considering drive and load state

This paper proposes a new research method in view of the rare research on the contact state of hybrid drive multi-degree-of-freedom motor. Firstly, the basic principle and structure of hybrid drive motor are introduced. The air gap magnetic field model and electromagnetic torque model of permanent magnet rotor are obtained by analytical method. Static analysis of piezoelectric stators are carried out by stress-strain relationship. According to the analytical method and the spatial geometric relationship, the piezoelectric driving torque under different driving conditions is obtained. Introducing Hertz contact theory and Mindlin theory, combined with piezoelectric driving torque, electromagnetic driving torque and load torque to analyze the friction situation. A friction interface model considering the dynamic nonlinearity of friction coefficient and the nonlinear change of friction force distribution is established. Finally, using Matlab software, the friction distribution diagram of the contact surface of the hybrid drive three-degree-of-freedom motor under different driving and motion states is obtained. The analysis results verify the rationality of the electromagnetic piezoelectric hybrid driven three-degree-of-freedom motor. It shows that the contact state of the three sets of piezoelectric stators are determined according to the driving condition and load, the relative speed of the piezoelectric stators and the spherical rotor is proportional to the frictional force. It provides an idea for the research of contact state of hybrid drive multi-degree-of-freedom motor, and also lays a basis for further optimizing the friction interface of this kind of motors or actuators.