Design and Experimental Analysis of Charge Recovery for Piezoelectric Fan

The piezoelectric (PE) fan is widely adopted in the field of microelectronics cooling due to its advantages of high reliability and good heat dissipation characteristics. However, PE fans driven by conventional circuits suffer from plenty of energy loss. To save energy, we propose an inductor-based charge recovery method and apply it to the driving circuit for the PE fan. Two inductor-based driving circuits, a single inductor-based driving (SID) circuit and a double inductor-based driving (DID) circuit are compared. The SID circuit has a simple structure and a slightly higher energy-saving rate, while the DID circuit introduces no additional oscillations and is more stable. The experimental results show that when the supply voltage changes, both circuits have a relatively stable energy-saving rate, which is about 30% for the SID circuit and 28% for the DID circuit. Moreover, the proposed circuits enjoy the same driving capacity as the conventional circuit, and the driven fan has the same cooling performance.

A Smart Energy Recovery System to Avoid Preheating in Gas Grid Pressure Reduction Stations

Preheating is often required to prevent hydrate formation during the pressure reduction process in a natural gas distribution network’s pressure reduction station. This paper examines an energy recovery method to avoid the cost and energy consumption of this preheating. The primary aim is to assess the techno-economic feasibility of an energy recovery system based on the Ranque–Hilsch vortex tube coupled to a heat exchanger for large-scale application to the gas grid. To this end, a techno-economic model of the entire energy recovery system was included in an optimisation procedure. The resulting design minimises the payback period (PP) when the system is applied to the pressure reduction stations belonging to a particular gas grid. The pressure reduction stations always operate at an outlet pressure above atmospheric pressure. However, available performance models for the Ranque–Hilsch vortex tube do not permit prediction at backpressure operation. Therefore, a novel empirical model of the device is proposed, and a cost function derived from several manufacturer quotations is introduced for the first time, to evaluate the price of the Ranque–Hilsch vortex tubes. Finally, a nearly complete set of pressure reduction stations belonging to the Italian natural gas grid was chosen as a case study using actual operating parameters collected by each station’s grid manager. The results indicate that the environmental temperature strongly affects the technical and economic feasibility of the proposed energy recovery system. In general, pressure reduction stations operating at an ambient temperature above 0 °C are economically desirable candidates. In addition, the higher the energy recovery system convenience, the higher the flow rate and pressure drop managed by the station. In the Italian case study, 95% of preheating costs could be eliminated with a PP of fewer than 20 years. A 40% preheating cost saving is still possible if the maximum PP is limited to 10 years, and a small but non-negligible 3% of preheating costs could be eliminated with a PP of fewer than 4.5 years.

Study of modern options for using combinations of gasflooding and traditional waterflooding (water-gas influence and its alternative)

Water-gas influence (WGI) is an oil recovery method improving displacement ratio, sweep efficiency and adjusting the alignment of displacement. This study is a review of the traditional WAG methods (Immiscible WAG, Hybrid WAG, Simultaneous WAG and Selective Simultaneous WAG), including with stabilizing surfactants, WAG. We also consider such sparsely used methods as: SSWAG, FAWAG, CWAG, TWAG, VR-WAG, Up- and Down-dip WAG, HC-WAG, PAG, SAG, WASP, LSW WAG, LSASF, SMSW-AGF and others. The advantages and disadvantages of these tools are considered. Keywords: water-gas influence (WGI); WAG; SWAG; enhanced oil recovery; APG

Optimized Design of 3D Spatial Images Based on Kalman Filter Equation

This paper takes the advantageous ability of Kalman filter equation as a means to jointly realize the accurate and reliable extraction of 3D spatial information and carries out the research work from the extraction of 3D spatial position information from multisource remote sensing optical stereo image pairs, recovery of 3D spatial structure information, and joint extraction of 3D spatial information with optimal topological structure constraints, respectively. Taking advantage of the stronger effect capability of Wiener recovery and shorter computation time of Kalman filter recovery, Wiener recovery is combined with Kalman filter recovery (referred to as Wiener-Kalman filter recovery method), and the mean square error and peak signal-to-noise ratio of the recovered image of this method are comparable to those of Wiener recovery, but the subjective evaluation concludes that the recovered image obtained by the Wiener-Kalman filter recovery method is clearer. To address the problem that the Kalman filter recovery method has the advantage of short computation time but the recovery effect is not as good as the Wiener recovery method, an improved Kalman filter recovery algorithm is proposed, which overcomes the fact that the Kalman filter recovery only targets the rows and columns of the image matrix for noise reduction and cannot utilize the pixel point information among the neighboring rows and columns. The algorithm takes the first row of the matrix image as the initial parameter of the Kalman filter prediction equation and then takes the first row of the recovered image as the initial parameter of the second Kalman filter prediction equation. The algorithm does not need to estimate the degradation function of the degradation system based on the degraded image, and the recovered image presents the image edge detail information more clearly, while the recovery effect is comparable to that of the Wiener recovery and Wiener-Kalman filter recovery method, and the improved Kalman filter recovery method has stronger noise reduction ability compared with the Kalman filter recovery method. The problem that the remote sensing optical images are seriously affected by shadows and complex environment detail information when 3D spatial structure information is extracted and the data extraction feature edge is not precise enough and the structure information extraction is not stable enough is addressed. A global optimal planar segmentation method with graded energy minimization is proposed, which can realize the accurate and stable extraction of the topological structure of the top surface by combining the edge information of remote sensing optical images and ensure the accuracy and stability of the final extracted 3D spatial information.

Recovery of continuous functions of two variables from their Fourier coefficients known with error

In this paper, we continue to study the classical problem of optimal recovery for the classes of continuous functions. The investigated classes $W^{\psi}_{2,p}$, $1 \leq p < \infty$, consist of functions that are given in terms of generalized smoothness $\psi$. Namely, we consider the two-dimensional case which complements the recent results from [Res. Math. 2020, 28 (2), 24-34] for the classes $W^{\psi}_p$ of univariate functions. As to available information, we are given the noisy Fourier coefficients $y^{\delta}_{i,j} = y_{i,j} + \delta \xi_{i,j}$, $\delta \in (0,1)$, $i,j = 1,2, \dots$, of functions with respect to certain orthonormal system $\{ \varphi_{i,j} \}_{i,j=1}^{\infty}$, where the noise level is small in the sense of the norm of the space $l_p$, $1 \leq p < \infty$, of double sequences $\xi=( \xi_{i,j} )_{i,j=1}^{\infty}$ of real numbers. As a recovery method, we use the so-called $\Lambda$-method of summation given by certain two-dimensional triangular numerical matrix $\Lambda = \{ \lambda_{i,j}^n \}_{i,j=1}^n$, where $n$ is a natural number associated with the sequence $\psi$ that define smoothness of the investigated functions. The recovery error is estimated in the norm of the space $C ([0,1]^2)$ of continuous on $[0,1]^2$ functions. We showed, that for $1\leq p < \infty$, under the respective assumptions on the smoothness parameter $\psi$ and the elements of the matrix $\Lambda$, it holds \[ \Delta( W^{\psi}_{2,p}, \Lambda, l_p)= \sup\limits_{ y \in W^{\psi}_{2,p} } \sup\limits_{\| \xi \|_{l_p} \leq 1} \Big\| y - \sum\limits_{i=1}^{n} \sum\limits_{j=1}^{n} \lambda_{i,j}^n ( y_{i,j} + \delta \xi_{i,j}) \varphi_{i,j} \Big\|_{C ([0,1]^2)} \ll \frac{ n^{\beta + 1 - 1/{p}}}{\psi(n)}.\]

Application of the train congestion recovery method for constructing an instantaneous direct current railway section

Improving the energy efficiency of the transportation process is one of the key tasks, the solution of which is one of the priority areas of the holding JSC «RZD» research. The successful solution of this problem depends, among other things, on the effectiveness of measures taken to reduce energy losses arising from electricity transmission to the consumer, which is the rolling stock of electrified railways. To develop a set of organizational and technical measures aimed at minimizing electricity consumption, an effective apparatus that provides determination of energy losses amount of in the electric-traction netware in real time is needed. The article proposes a method for hardware-analytical calculation of energy losses, which is based on an algorithm for processing the results of direct measurements. It is proposed to calculate power losses using laws and relationships known from the course of electrical engineering. A distinctive feature of the proposed method is the function of recreating the instantaneous circuit based on the data of currents and voltages measurements at the control points of a given section. The proposed method is suitable for use exclusively on DC electrified railways. Also, the paper presents the methods for determining energy losses used today in Russia, and gives their brief characteristics. The logical and mathematical apparatus of the method is described in detail, indicating the possible reasons that, in the process of synthesizing instantaneous circuits, can affect the occurrence of errors. An assessment of the study results of this method application in the electric-traction netware of railways is given.

A Dual-Directional Flow Control Device for Cyclic Steam Stimulation Applications

Summary Cyclic steam stimulation (CSS) is one the most effective thermal recovery methods. It is widely used as the primary thermal recovery method to recover heavy oil fields in the Middle East, the Asia-Pacific region, and North and South America. In this paper, a novel dual-directional flow control device (FCD) will be introduced. This FCD technology can allocate accurate steam outflow into the reservoir formation and improve steam quality during the steam injection period and can mitigate steam breakthrough from the neighboring wells during the production period. In the first section, we give a brief introduction on CSS and the main issues encountered in the field operation. A multidirectional flow control nozzle specifically designed for CSS application will be presented. Design philosophy in thermodynamics and hydrodynamics of the nozzle will be discussed in detail. Field performance results, computational fluid dynamics (CFD), and flow loop testing data will be shown to evaluate the performance of the technology. The application of the technology in steam-assisted thermal applications will be introduced. Well-known issues such as erosion and scaling on the FCD tools will be studied in the end.