Optimization of Historic Building Survey Technology under Artificial Intelligence Wireless Network Technology Environment

In order to optimize the technology of the building, the damage identification of the building structure is studied. Firstly, back propagation neural network (BPNN) and information fusion technology are used to build neural network models. Secondly, the established model is trained. Finally, the displacement mode, natural frequency, Modal Assurance Criterion (MAC), and three kinds of information fusion with only one characteristic information are used as input data to analyse the results of BPNN identification damage. The results show that when the natural frequency is used as the sensitive feature of damage, the accuracy is the highest. The difference between the network output value and the expected value is the smallest, the network output is the most stable, and the network recognition effect is the best. The network output of a mixture of two damage depths is compared with the output of a single damage depth. The data of the network training set composed of the feature data with damage depth of 20 mm and 5 mm has higher accuracy and more accurate damage recognition. This research provides a reference for the optimization of building survey technology and has certain practical value.

Theoretical and experimental investigation of MWCNT dispersion effect on the elastic modulus of flexible PDMS/MWCNT nanocomposites

In this article, Young’s modulus of a flexible piezoresistive nanocomposite made of a certain amount of multiwalled carbon nanotube (MWCNT) contents dispersed in polydimethylsiloxane (PDMS) has been investigated using theoretical and experimental approaches. The PDMS/MWCNT nanocomposites with the governing factor of MWCNT weight fraction (e.g., 0.1, 0.25, and 0.5 wt%) were synthesized by the solution casting fabrication method. The nanocomposite samples were subjected to a standard compression test to measure their elastic modulus using Instron Universal testing machine under force control displacement mode. Due to the costs and limitations of experimental tests, theoretical predictions on the elasticity modulus of such flexible nanocomposites have also been performed using Eshelby–Mori–Tanaka (EMT) and Halpin–Tsai (HT) approaches. The theoretical results showed that HT’s approach at lower MWCNT contents and EMT’s approach at higher MWCNT contents have a better agreement to experimental results in predicting the elastic modulus of PDMS/MWCNT nanocomposites. The experimental results indicated that the inclusion of MWCNT in the PDMS matrix resulted in a noticeable improvement in Young’s modulus of PDMS/MWCNT nanocomposite at small values of MWCNT contents (up to w f = 0.25%); however, exceeding this nanofiller content did not elevate Young’s modulus due to the emergence of MWCNT agglomerations in the nanocomposite structure.

Two-wave laser displacement meter

A two-wave laser displacement meter based on Michelson interferometer has been developed for measurements at an unknown temperature profile at the measurement trace. The requirements for meteorological parameters support during displacement measurements using the offered laser interferometer are less strict compared to using an one-wave interferometer. The article describes the optical schematic of the device. The results for the measurements of the developed laser interferometer for realization of the displacement unit within the limits of 60 m are presented. The weather condition influence on measurements was estimated. The application of pseudorandom displacement of the interferometer’s reference arm with accumulation made possible the reflector position resolution down to 0.01 μm the stoped-displacement mode, and down to 0.05 μm at the displacement mode. It was shown that such resolution allows to measure displacements at trace up to 60 m with inaccuracies less than 10 μm at the temperature profile amplitude up to 1 °C.

Water denitrification by displacement biofiltration

This work was aimed creating a simple and reliable submersed biofilter for the decentralized treatment of nitrate-contaminated water. Denitrification of water was studied by the method of displacement (piston) bio-filtration in specially designed devices intended for home application. At certain sizes of grains of bio-filtration bed and filtration flow directions in it, the change in operating mode of denitrifying biofilter from direct flow to displacement mode offers the following advantages. There is no need to maintain a continuous and slow flow of water through the biofilter. The consumers have the opportunity to feed big portions of water into the bio-filter in one gulp (pulse) and nevertheless get the same quantity of denitrified water. The design of created biofilters is simple. Assembling these bio-filters implies the use of materials with a minimum carbon footprint.

Analysis of Earth Pressure Variation for Partial Displacement of Retaining Wall

Parts of the retaining wall might produce displacement under different load conditions. The moveable wall could impact the adjacent fixed wall, mainly reflecting on the variation of earth pressure and formation of the soil arching effect. This paper conducted the horizontal trap-door test to explore the variation of active earth pressure caused by partial displacement of the retaining wall. Different trap-door width and three displacement modes were addressed as the influence factors. The results indicated that the horizontal soil arching effect was generated after the active displacement of the trap-door and the soil pressure was redistributed. The distribution of lateral soil pressure was approximately an “inverted bell” curve. For trap-door widths of 20 cm, 30 cm, and 40 cm, a secondary soil arching effect appeared in the test. The relationship between lateral earth pressure and displacement was different with the traditional limited theory due to the influence of the soil arching effect. The variation curve of earth pressure corresponding to displacement could be divided into three stages. In addition, the distribution of earth pressure along the trap-door height was non-linear. Trap-door width can significantly influence the maximum earth pressure on the fixed wall and the range where pressure changes. Finally, the effect of load sharing was explored and found to be related with displacement and width of trap-door as well as the displacement mode.

Vertex Displacement-Based Discontinuous Deformation Analysis Using Virtual Element Method

To avoid disadvantages caused by rotational degrees of freedom in the original Discontinuous Deformation Analysis (DDA), a new block displacement mode is defined within a time step, where displacements of all the block vertices are taken as the degrees of freedom. An individual virtual element space V1(Ω) is defined for a block to illustrate displacement of the block using the Virtual Element Method (VEM). Based on VEM theory, the total potential energy of the block system in DDA is formulated and minimized to obtain the global equilibrium equations. At the end of a time step, the vertex coordinates are updated by adding their incremental displacement to their previous coordinates. In the new method, no explicit expression for the displacement u is required, and all numerical integrations can be easily computed. Four numerical examples originally designed by Shi are analyzed, verifying the effectiveness and precision of the proposed method.

Analysis of Mechanical Behaviors of Waterbomb Thin-Shell Structures Under Quasi-Static Load

Waterbomb structures are origami-inspired deformable structural components used in new types of robots. They have a unique radially deployable ability that enables robots to better adapt to their environment. In this paper, we propose a series of new waterbomb structures with square, rectangle, and parallelogram base units. Through quasi-static axial and radial compression experiments and numerical simulations, we prove that the parallelogram waterbomb structure has a twist displacement mode along the axial direction. Compared with the square waterbomb structure, the proposed optimal design of the parallelogram waterbomb structure reduces the critical axial buckling load-to-weight ratio by 55.4% and increases the radial stiffness-to-weight ratio by 67.6%. The significant increase in the radial stiffness-to-weight ratio of the waterbomb structure and decrease in the critical axial buckling load-to-weight ratio make the proposed origami pattern attractive for practical robotics applications.

ESTIMATION OF HETEROGENEITY OF THE ATMOSPHERIC AIR VELOCITY FIELD IN ADSORBERS OF FRONT-END PURIFICATION UNITS FOR AIR SEPARATION PLANTS

Assuming unidirectional motion of compressed atmospheric air through a vertical cylindrical adsorbent with a fixed granular layer of the front-end purification unit adsorbent, the mathematical model for estimating the heterogeneity of a hydrodynamic velocity field in the radial and axial directions in a turbulent regime is proposed. The model is based on the boundary layer approximation of the Darcy – Brinkman – Forchheimer phenomenological equation. The steady-state flow at low permeability of the granular layer is identified using the collocation method, and the approximate analytical solution is obtained which justifies the applicability of an ideal displacement mode when describing the carrier medium motion. Numerical integration of a boundary value problem of the model equation using the finite-difference method with Richardson extrapolation confirms the conclusion validity. The structure of an accelerated turbulent flow having constant flow velocity in the input section shows that for small Forchheimer coefficients, the Darcy – Brinkman equation is used to obtain the analytical ratio for calculating the length of the initial hydrodynamic section. The proposed mathematical model for estimating the heterogeneity of the velocity field in adsorbers with a stationary dispersed layer is applicable for a laminar flow regime. Testing of this approach by assessing velocity field uniformity for a mass-produced front-end purification unit of air separation plants has shown its efficiency.

Laboratory Results of the Influence of Carbon Dioxide on the Development of the Permo-Carboniferous Reservoir of the Usinskoe Deposit

As an option for enhancing oil recovery of a high-viscosity Permo-Carboniferous reservoir associated with the Usinskoye field, the use of technology based on technogenic carbon dioxide as an injection agent is considered. In the world practice, several fields are known as close in their parameters to the parameters of the Permo-Carboniferous reservoir, and in which CO2 injection was accepted as successful. Based on this, CO2 injection can potentially be applicable in the conditions of a Permo-Carboniferous reservoir. At present, as a result of the various development technologies implementation, reservoir zones are distinguished, characterized by different thermobaric properties. Depending on reservoir conditions, when displacing oil with gases, various modes of oil displacement can be realized. This article describes the results of studies carried out to study the effect of the concentration of carbon dioxide on the properties of high-viscosity oil in the Permo-Carboniferous Reservoir of the Usinskoye field, as well as the results of filtration experiments on slim models performed to assess the oil displacement regime under various temperature and pressure conditions of the Permo-Carboniferous Reservoir. The study of the influence of CO2 concentration on oil properties was carried out using the standard PVT research technique. The displacement mode was assessed using the slim-tube technique. Based on the performed experiments, it was established that an increase in the concentration of CO2 in high-viscosity oil led to a noticeable change in its properties; for the conditions of a Permo-Carboniferous Reservoir, the most probable mode of oil displacement by carbon dioxide was established. Difficulties associated with the preparation of the CO2-heavy oil system were described separately. Based on a literature review, it was shown that the rate of mixing of oil with carbon dioxide depended on certain conditions.