bluuebunny/crossref_metadata_2025 huggingface dataset:
Empirical Evaluation of Computer-Adaptive Alternate Short Forms for the Assessment of Anomia Severity
Authors: Hula William D. , Fergadiotis Gerasimos , Swiderski Alexander M. , Silkes JoAnn P. , Kellough Stacey
Published: December 2019

Purpose

The purpose of this study was to verify the equivalence of 2 alternate test forms with nonoverlapping content generated by an item response theory (IRT)–based computer-adaptive test (CAT). The Philadelphia Naming Test (PNT; Roach, Schwartz, Martin, Grewal, & Brecher, 1996)was utilized as an item bank in a prospective, independent sample of persons with aphasia.

Method

Two alternate CAT short forms of the PNT were administered to a sample of 25 persons with aphasia who were at least 6 months postonset and received no treatment for 2 weeks before or during the study. The 1st session included administration of a 30-item PNT-CAT, and the 2nd session, conducted approximately 2 weeks later, included a variable-length PNT-CAT that excluded items administered in the 1st session and terminated when the modeled precision of the ability estimate was equal to or greater than the value obtained in the 1st session. The ability estimates were analyzed in a Bayesian framework.

Results

The 2 test versions correlated highly (
r
= .89) and obtained means and standard deviations that were not credibly different from one another. The correlation and error variance between the 2 test versions were well predicted by the IRT measurement model.

Discussion

The results suggest that IRT-based CAT alternate forms may be productively used in the assessment of anomia. IRT methods offer advantages for the efficient and sensitive measurement of change over time. Future work should consider the potential impact of differential item functioning due to person factors and intervention-specific effects, as well as expanding the item bank to maximize the clinical utility of the test.

Supplemental Material

https://doi.org/10.23641/asha.11368040
Spectral efficiency analysis of multi‐cell multi‐user massive MIMO over channel aging
Authors: Xin Yuanxue , Shi Pengfei , Xia Xinjiang , Fan Xinnan
Published: December 2019

To achieve the expected attractive potential of massive multiple‐input multiple‐output (MIMO), accurate match between the receiver and the actual channel is necessary. Due to the channel aging, this kind of mismatch appears in the vast majority of practical propagations. Consequently, the impact of channel aging for massive MIMO is investigated in this study. The authors first propose an equivalent estimated channel model by considering the inevitable time‐varying nature of channels in realistic mobile communications. Then, they obtain the achievable uplink rate based on the proposed equivalent channel models. In particular, the closed‐form expression of the asymptotic uplink rate is derived. Different from the existing works, this study considers the joint multi‐cell minimum‐mean‐squared‐error (MMSE) channel estimator and MMSE receiver for massive MIMO systems over aging channels. Through the simulation, it demonstrates that adopting massive MIMO can compensate for the performance loss caused by channel aging. In addition, this pstudy gives some insights into the system design: to achieve the best performance, system with higher‐mobility terminals should be operated with more pilot resources, and it can support more users, moreover, the optimal number of users supported in a cell is less than half of the coherence time interval.
Robust design for reducing cogging torque in surface‐mounted permanent magnet synchronous motor considering tolerances of sub‐components
Authors: Lee Byeong‐Hwa , Jung Jae‐Woo
Published: December 2019

This study deals with a robust design for cogging torque reduction considering the production tolerances of motor sub‐components, which is related to the dimensions of the permanent magnet and stator core shape. A 14‐pole and 12‐slot fractional slot concentrated winding motor is employed as the design model. Prior to a robust design, an initial model was implemented to satisfy the torque demand within some constraints. In the robust design, the main design variables were first selected for the design of experiment (DOE). The interaction effects were investigated using the full factorial design, which is one of the DOE techniques. Next, the direction of design variables to minimise the cogging torque and improve the signal‐to‐noise ratio were confirmed using the Taguchi method. Then, the response surface methodology was implemented based on the result from the Taguchi method to yield an optimum value of the design variables and approximate equivalent polynomial equation. Finally, the normal distribution curve of the cogging torque was simply determined by the equivalent polynomial equation using the Monte‐Carlo method taking production tolerances based on the process capability of the sub‐components into consideration.
Converter‐level reliability prediction and analysis in switched reluctance motor drive
Authors: Xu Shuai , Chen Hao , Dong Feng
Published: December 2019

Reliability has been a dominant factor in the performance of power converters. In this study, an enhanced k‐out‐of‐n:G model is presented to predict and analyse the reliability of typical asymmetric half‐bridge power converter in switched reluctance motor drive. First, the reliability estimation procedure is introduced including electrothermal model, failure rate model, and reliability model, during which the electrothermal model is critical to accelerate the process of reliability prediction. Next, the enhanced k‐out‐of‐n:G model can be built, and corresponding solving process is derived. Meanwhile, the reliability comparison is quantitatively illustrated between conventional k‐out‐of‐n:G models, generally accepted Markov model, and enhanced k‐out‐of‐n:G model, indicating the result with the proposed model is consistent with Markov model. Moreover, the modelling and solving processes are simpler. Then, the reliability is optimised in respect to turn‐on angle, turn‐off angle, and fault‐tolerance strategies with the enhanced k‐out‐of‐n:G model, providing a guideline to select the most effective control parameters and strategies for reliability improvement. Finally, the fault experiments and thermal stress measurement are carried out to indirectly validate the reliability analysis.
New finite element based method for thermal analysis of axial flux interior rotor permanent magnet synchronous machine
Authors: Habibinia Davod , Rostami Naghi , Feyzi Mohammad Reza , Soltanipour Hossein , Pyrhönen Juha
Published: December 2019

A new method for computing convection heat transfer coefficients in axial flux permanent magnet synchronous machines (AF‐PMSMs) is introduced. The method is based on a two‐step finite element analysis (FEA). In the first step, a simple 2D model is introduced and fluid flow and temperature fields are studied using computational fluid dynamic (CFD) technique. Convective heat transfer coefficients for all heat transfer surfaces of the model are extracted from CFD analysis and are then used as inputs to a 3D thermal finite element model. Two case studies are considered to check the accuracy of the abovementioned two‐step method. One of the case studies is an air‐cooled AF‐PMSM that has air inlet and outlet on its enclosure and the other case is a totally enclosed AF‐PMSM. The correctness of the mentioned method is verified by practical measurements on the second case. In addition, an experimental set‐up is conducted to measure the temperature of different parts of the second case. It is observed that the results of the two‐step CFD‐FEA model are in good agreement with the experimental data. In the other case, the effect of inlet air velocity on heat transfer coefficients, as well as the thermal behaviour of the machine are explored.
Fast calculation method of optimal flux‐barrier‐end position for torque ripple minimisation in SynRMs with and without PMs
Authors: Xu Meimei , Liu Guohai , Chen Qian , Zhao Wenxiang
Published: December 2019

This study presents a simplified analytical model for synchronous reluctance machines (SynRMs) with and without permanent magnets (PMs) to rapidly investigate the influences of flux‐barrier‐end angles or salient poles angles on the torque ripple. With the proposed method, the optimal flux‐barrier‐end angles or salient poles angles can be computed directly to eliminate a specific torque harmonic. To further minimise two main low‐order torque harmonics, a compensation strategy is adopted by choosing different optimised flux‐barrier‐end angles or salient poles angles in rotor adjacent poles. Moreover, two types of optimal combinations are evaluated and compared with transient finite element analysis. The results show the torque ripple can be significantly reduced in the optimised SynRMs with and without PMs and the average torque loss is acceptable. Finally, the prototype motor of five‐phase SynRMs without PM is built and tested to validate the analyses.
Simultaneous radial deformation and partial discharge detection of high‐voltage winding of power transformer
Authors: Karami Hossein , Gharehpetian Gevork B. , Norouzi Yaser , Akhavan‐Hejazi Maryam
Published: December 2019

Condition monitoring of power transformers has attracted a lot of attention due to their important roles in determining power system reliability. Radial deformation of power transformer winding should be monitored online to prevent more damages to winding and possible transformer outage. The ultra‐high‐frequency (UHF) stepped‐frequency synthetic‐aperture radar imaging method has recently been proposed as an online method for high‐voltage winding radial deformation detection. On the other hand, partial discharge (PD) as another defect of the transformer winding propagates UHF signals in the transformer environment, which should be detected online. In this study, the practical application of a designed monitoring system is investigated for simultaneous online detection of both PD and radial deformation defects in a real three‐phase power transformer. In addition, radial deformation is localised through a monitoring system designed based on the proposed method. Using this system, only one set of antennas is needed to detect both defects which lead to reducing the number of installed antennas and economic application of the monitoring system.
High‐precision non‐linear modelling method for a switched reluctance linear machine by interpolation with using variant sigmoid function
Authors: Nie Rui , Chen Hao , Wang Haiying , Zhao Shuyan , Wang Xing , Pires Vitor , Martins João , Gorbounov Yassen
Published: December 2019

This study presents a non‐linear modelling method for a switched reluctance linear machine (SRLM), which achieves high modelling precision while requiring no prior knowledge regarding the specific structural dimensions of an SRLM. The proposed modelling method provides accurate flux linkage data based on limited experimental measurements through an interpolation process using a variant sigmoid function. The accuracy of the interpolation process is further increased by considering mutual coupling among the three phases. The performance of the proposed method is validated experimentally by comparing it with the performances of the Fourier series method and the two‐dimensional finite element method. The results demonstrate that the proposed method achieves greater modelling precision than the other methods considered in modelling an SRLM.
Torque ripple error compensation of high‐dynamic coil array commutation algorithm for magnetic levitation planar motor
Authors: Sun Haobo , Cheng Rong , Yang Kaiming , Zhu Yu , Lu Sen
Published: December 2019

In the magnetic levitation planar motor which can achieve six degrees‐of‐freedom motion, decoupling control is realised by coil array commutation algorithm, due to the limitation of the sampling period of the real‐time system, a high‐dynamic coil array commutation algorithm is needed to achieve higher computational efficiency, but this will lead to the coil array not accurately providing the force/torque required for the trajectory movement, and generate a certain torque ripple error. In this study, the cause of this torque ripple error is analysed, and a feedforward compensation method is proposed. The results of simulation and experiment show that the proposed feedforward compensation method of high‐dynamic coil array commutation algorithm can reduce torque ripple error by 88%, and achieve higher trajectory tracking accuracy while satisfying high computational efficiency.
Scheme for synchronous machine stator turn‐to‐turn protection
Authors: Platero Carlos A. , Gyftakis Konstantinos N. , Panagiotou Panagiotis A. , Fernandez Alba
Published: December 2019

This study presents a new protection scheme for turn‐to‐turn fault protection in the stator windings of synchronous machines. The main difference with other methods is the calculation of voltage of the winding from the phase to ground and neutral to ground voltages, which can be obtained from the monitoring provided by any commercial generator multifunction protection relay. This new method allows the employment of the protection transformers already installed in the protection scheme, simplifying and reducing the cost of the protection function. To validate this new technique, finite element method simulations and numerous tests have been performed in a specially built synchronous generator with taps in one of the stator windings. In this way, several turn‐to‐turn faults have been created at different fault severity levels.
High‐performance speed estimation of induction machines based on adaptive filtering
Authors: Petrić Ivan , Vukosavić Slobodan
Published: December 2019

This paper presents a novel algorithm for sensorless detection of the rotor speed applied to induction machines, which relies on rotor slot harmonics (RSHs). The estimator structure is proposed, for extracting and tracking the RSH found in the stator line current, which offers improved results compared with previously published methods. The proposed method reduces delays, output jitter, and steady‐state error. A stability analysis is provided and used in the design procedure to ensure system reliability. The capability of using the estimated signal as speed feedback in a sensorless drive is tested and confirmed. The system employs a bandpass filter with a centre frequency that is adapted according to the estimated speed, a high bandwidth phase‐locked loop, and an observer. Tracking limits and parameter design are explained analytically; the method is verified in simulations and confirmed experimentally. Experimental verification is performed on a standard three‐phase induction motor, using a three‐phase pulse‐width modulation inverter.
Quasi‐Z source indirect matrix converter‐fed induction motor drive
Authors: Guo Mingzhu , Liu Yushan , Ge Baoming , Liu Shuo , Li Xiao , Ferreira Fernando J.T.E. , de Almeida Anibal T.
Published: December 2019

This study proposes an induction motor drive system based on the LC filter integrated quasi‐Z source indirect matrix converter (QZS‐IMC). The proposed drive system shows the following features: (i) variable voltage control of inductor motor is achieved by the rectifier stage and variable frequency control is achieved by the inverter stage; (ii) automatic low voltage ride through ability enhances capability of the proposed drive against grid voltage sag; (iii) wide voltage gain range ensures the drive system with high performance in wide speed range; (iv) there is no additional input filter. The voltage control implementation in the rectifier stage is proposed to benefit low voltage stress and low converter loss. The control method combines motor vector control, minimum shoot‐through duty cycle and maximum modulation indexes. As a result, the input power supply voltage and dc‐link voltage are maximally utilised and the power loss is reduced. Simulation and experimental results verify the proposed QZS‐IMC motor drive system.
Analytical modelling and optimisation of line start LSPM synchronous motors
Authors: Ghahfarokhi Mohammadreza M. , Aliabad Aliakbar Damaki , Boroujeni Samad Taghipour , Amiri Ebrahim , Faradonbeh Vahid Zamani
Published: December 2019

This study presents a comprehensive analytical analysis of line start permanent magnet (LSPM) synchronous motors in both steady‐state and transient domains. The PM flux, the back‐EMF and the winding inductances are first calculated in the steady‐state based on the hybrid solution of magnetic circuit and the magnetic islands. Next, the motor voltage relations are mapped into an arbitrary d‐q reference frame to dynamically assess the transient speed response as well as the individual motor torque components. Based on the presented analytical modelling, the parameters of the motor are optimised via genetic algorithm to maximise the back‐EMF voltage and the overall steady‐state performance. Given the parabolic relation between the back‐EMF and the braking torque, the starting capability of the motor is defined as the optimisation constraint. Finally, the analytical results are verified by using a finite element analysis software package.
Bidirectional multiport solar‐assisted SRM drive for pure electric vehicle applications with versatile driving and autonomous charging capabilities
Authors: Thankachan Jose , Singh Sajjan Pal
Published: December 2019

Pure electric vehicles (PEVs) offer a solution for achieving a zero‐emission transport system. This study presents the work towards the development of a bi‐directional multiport solar‐assisted switched reluctance motor (SRM) drive for PEV applications having battery‐to‐vehicle (B2V), photovoltaic (PV)‐to‐vehicle (PV2V), PV assisted B2V, grid‐to‐vehicle battery charging and PV2V battery charging functions. The power circuit is formed by the combination of a front‐end circuit and a modified‐Miller SRM converter. Battery, PV panel, grid and SRM form the four ports of this multiport drive, which with proper control, provide motoring, braking and charging functions. The dc‐link voltage is fully controllable which improves the machine performance both at higher and lower speeds. During stand‐still conditions, the battery is charged either from the grid at unity power factor or through the PV panel by incorporating the drive components to form an on‐board battery charger, thereby reducing the reliance on charging stations. A fault‐tolerant control is developed to operate the system with desired performance under single and double phase open‐circuit faults. An 8/6 SRM is used for proof of concept and the experimental results confirm the effectiveness of the proposed drive and control strategy.
MPTC of NP‐clamped three‐level inverter‐fed permanent‐magnet synchronous motor system for NP potential imbalance suppression
Authors: Peng Shihao , Zhang Guozheng , Zhou Zhanqing , Gu Xin , Xia Changliang
Published: December 2019

For neutral point (NP)‐clamped three‐level inverter‐fed permanent‐magnet synchronous motor system, the tuning process of weighting factors in the cost function of conventional model‐predictive torque control (MPTC) is complex. Also, large imbalance of NP potential can cause the deteriorated performance of flux and torque. To solve these problems, an improved MPTC is proposed. This algorithm first uses the deadbeat principle to unify the dimension of torque and flux. Then, the NP potential term in the conventional cost function can be eliminated by introducing the partition control of NP potential imbalance, which also eliminates the whole process of tuning weighting factors. After that, under the large NP potential imbalance, sectors are dynamically divided by modifying the magnitude and phase angle of medium and small vectors to improve the performance of torque and flux linkage. The experimental results show that compared with conventional MPTC, the improved MPTC can achieve fast suppression of NP potential imbalance with reducing the fluctuation of torque, flux linkage and current when NP potential imbalance is large.
Research on a hybrid excitation PM synchronous generator with stator third harmonic winding excitation
Authors: Xia Yonghong , Wen Zijian , Zhu Ziqiang , Zhong Shihua , Chen Ying , Zhang Jingming
Published: December 2019

This study presents a hybrid excitation permanent magnet synchronous generator (HEPMSG) with a stator third harmonic winding to solve the problems of adjusting the air‐gap magnetic field of the permanent magnet synchronous machine (PMSM) and simplify the excitation system structure. The electromotive force (EMF) of the stator third harmonic winding, induced by the inherent third harmonic magnetic field in the air gap, provides the adjustable field current for the rotor field winding via the controllable rectification. The proposed machine structure is described, and the generation mechanism and the excitation principle of the stator third harmonic EMF are analysed. The conditions for maximum excitation current output are discussed, and the integrated design methods of the stator third harmonic winding and the rotor excitation winding are described. Based on the finite element method, the performances of the third harmonic excitation system are numerically compared for different stator third harmonic windings, and the open‐circuit voltage regulation characteristics under different control angles are analysed. A 2.5 kW HEPMSG prototype with a stator third harmonic winding is manufactured and tested. The predicted and experimental results are in good agreement, which verifies the correctness of the excitation principle of the proposed HEPMSG.
Decoupling control of a dual‐stator linear and rotary permanent magnet generator for offshore joint wind and wave energy conversion system
Authors: Xu Lei , Zhang Chao , Zhu Xiaoyong
Published: December 2019

Wind and wave energy are the main forms of offshore energy. In this study, a new joint wind and wave energy (JWWE) power conversion system, which simultaneously features wind power generation and wave power generation, is investigated. In the JWWE power generation system, a dual‐stator linear and rotary permanent magnet generator (DSLRPMG) is employed to directly convert the wind and wave energy. The topology and operating principles of the power generation system are analysed, and the rectifier topology with two three‐phase bridge converter is introduced for the JWWE power generation system. On the basis of the vector control method, the mathematical model of the DSLRPMG is deduced. The virtual flux direct power control method without any AC voltage sensors is applied for the power generation system. A new decoupling control method including flux decoupling and power decoupling is proposed and analysed. Meanwhile, an experimental setup is constructed, and the experiments are done. Both the simulation and experimental results show the validity and correctness of the control strategy.
Performance of a superconducting breaker for the protection of HVDC grids
Authors: Etxegarai Agurtzane , Larruskain Dunixe Marene , Iturregi Araitz , Saldaña Gaizka , Apiñaniz Susana
Published: December 2019

Future multi‐terminal high‐voltage direct current (HVDC) grids will be essential for the electric power system expansion. However, there are still several technical, economic and legal obstacles that interfere with the construction of those grids. One of the main technical issues is the interruption of DC currents when a fault occurs, due to the high values of DC fault currents that can exceed the DC circuit breakeŕs (DCCB) interruption capability in few milliseconds. In order to overcome that limitation, a superconducting DCCB (S‐DCCB) is presented in this study. The proposed S‐DCCB is based on the combination of a superconducting fault current limiter, a mechanical DC circuit breaker and a current limiter reactor. The presented S‐DCCB is modelled and simulated by PSCAD/EMTDC software on a four‐terminal HVDC system. Its behaviour is proven to be satisfactory for several fault scenarios. DC fault currents are initially limited and afterwards interrupted by the S‐DCCB in an operation time that fulfils DC grids' protection requirements.
Compact on‐chip millimetre wave bandpass filters with meandered grounding resonator in 0.13‐μm (Bi)‐CMOS technology
Authors: Luo Cong , Wong Sai‐Wai , Chen Rui‐Sen , Zhu Xi , Yang Yang , Lin Jing‐Yu , Tu Zhi‐Hong , Xue Quan
Published: December 2019

In this study, an ultra‐compact meandered grounding resonator is proposed to design two millimetre wave bandpass filters (BPFs) in a standard 0.13‐µm silicon‐germanium (Bi)‐complementary metal oxide semiconductor (CMOS) technology. The fundamental second‐order prototype, namely BPF‐I, consists of a pair of proposed resonators and a pair of grounded metal‐insulator‐metal (MIM) capacitors. To better understand the principle of the second‐order BPF‐I, an equivalent LC‐circuit model and theoretical analysis method are presented in this study. Based on BPF‐I, the second‐order BPF‐II is proposed by adding the additional two pairs of MIM capacitors to improve the frequency selectivity, by means of introducing a transmission zero at lower stopband. Finally, both of the two second‐order BPFs are fabricated. The measured results show a good agreement with the full‐wave simulation results. The insertion loss of the first BPF‐I is 1.79 dB at the centre frequency of 46.6 GHz, and the fractional bandwidth is up to 96.5%. The second BPF‐II has a centre frequency at 46.8 GHz with a fractional bandwidth of 94.1%. The minimum insertion loss is 2.08 dB and the lower stopband attenuation is up to 42.7 dB. Moreover, the die sizes of the two compact BPFs, excluding the test pads, are only 0.0197 mm2 (0.104 × 0.190 mm2).
TSV‐based antenna for on‐chip wireless communication
Authors: Pano Vasil , Tekin Ibrahim , Liu Yuqiao , Dandekar Kapil R. , Taskin Baris
Published: December 2019

On‐chip wireless interconnects provide signal broadcasting and link shortcuts for improved latency and throughput, useful considering the increase of the number of processing elements on a chip. In this work, a through‐silicon via antenna (TSV_A) for on‐chip wireless communication is proposed. TSV_A significantly improves the wireless interconnect performance over current solutions of on‐chip antennas, which occupy a large area of the chip and are not capable of far‐reaching transmission. Printed circuit board (PCB) prototypes are designed and fabricated to validate the proposed TSV_A. The PCB prototype of the TSV_A has an insertion loss of 5–10 dB at a distance of ≃20 mm, measured in PCB and validated with high fidelity 3D finite element method simulation results. TSV_A has improved path loss, smaller size, and lower manufacturing costs due to the well‐established TSV fabrication process for 3D‐ICs. Projections for an on‐chip 3D‐IC operation indicate up to 40 dB improved signal strength compared to other on‐chip antennas, with an insertion loss of ≃3–5 dB up to a 30 mm distance.
Comparative analysis of IoT based products, technology and integration of IoT with cloud computing
Authors: Sharma Bhisham , Obaidat Mohammad S.
Published: December 2019

The advanced technology Internet of Things (IoT), a recent development in wireless sensor networks, provides a way to connect surrounding physical objects to the Internet in a dynamic way. There is an advantage of using IoT technology protocols as it requires less network bandwidth, minimum code space and hence reduces access time. Major IoT provider companies have several IoT products in the gadget market to make consumers’ life effortlessly easy. Several research gaps regarding the scalability of IoT with other platforms have been identified by reviewing the existing literature and also explained essential information about the integration of IoT with cloud computing. Major technology big giants Apple, Google, and Amazon's products are differentiated on the basis of measurement parameters such as their prices, streaming options, customisable appearance methods, major partnership companies related information appearing. A prototype of Apple's Home Kit and Samsung SmartThings is developed to show the characteristics of smart home products for the user, which helps in better decision making of IoT platform providers.
Spatial–temporal waveform design for MIMO radar without approximating the covariance matrix
Authors: Zhang Bo , Dai Fengzhou
Published: December 2019

In this study, a transmit waveform design method based on spatial–temporal optimisation for multiple‐input multiple‐output (MIMO) radar is proposed. The goal is not only to design the waveforms for beampattern matching, but also to minimise the autocorrelation sidelobes of the spatial synthesis signals of interested direction. Especially, to synthesise the constant envelope waveform directly, an improved sequential convex algorithm is proposed to tackle the non‐convex problem in spatial optimisation. Then the autocorrelation sidelobes are reduced by using the steepest descent algorithm in temporal optimisation. Finally, the authors assess the effectiveness of the proposed technique through numerical simulations in comparison with the traditional and the alternating direction method of multipliers method.
High-temperature processing of municipal solid waste
Authors: Barysheva Olga , Khabibullin Yuri , Mukhametzianova Aida
Published: December 2019

At present, processing and recycling of municipal solid waste (MSW) has become more relevant in our country and the world at large. This problem concerns large towns and cities, where every year millions of tons of all kinds of fractions of household waste are produced. Disposal or recycling of solid waste is an environmental issue, but it is associated with the solution of complex technical, energy and economic challenges. The purpose of this study is to identify the advantages and disadvantages of modern methods of processing and disposal of MSW with the prospect of developing and creating a device for recycling MSW taking into account modern approaches to energy saving and environmental protection. The main results of the study are to create a simple, reliable and technically sound method of MSW disposal to obtain additional energy. The significance of the results obtained for the construction industry is the design of a device for the disposal of solid waste with the production of solid combustion products and further their use as building materials and products for various purposes. Because of the technological process of MSW processing, it becomes possible to generate some returns through use of resulting thermal energy for electricity production.
Energy Complex of a Municipality on the Example of Luleå (Sweden)
Authors: Stoyanov Alexander
Published: December 2019

The following work focuses on the study of the energy complex in a particular country (Sweden) and in specific conditions (Luleå municipality in the first and second decades of the 21st century). The conclusions and results obtained during the work might be interesting from the point of view of applicability of practice in other countries, as an example of successful experience in implementing an effective fuel and energy complex, which allows each of the parties (producers and consumers) to derive the maximum mutual benefit. The main features of the energy economy of Sweden as a whole have also been considered, which may contribute to the deepening of research in this vein, in order to allow other municipalities to be considered, which in turn will make it possible to assess the efficiency and prospects of the fuel and energy complex in the country as a whole. The work also proposes and considers possible points of intensification of the production cycle in order to increase production capacities and improve the conditions for consumers who, due to the geographical features of the country’s location, are forced to spend large amounts of money on innovative technologies, illustrated in consumer prices for electricity and heat supply (especially other municipalities in Sweden, for example, the difference between Luleå and them in terms of consumer prices can reach 30-40%).
The assessment of the series active filter efficiency in power supply systems of oil production enterprises
Authors: Sychev Yuriy , Zimin Roman , Aladin Maxim
Published: December 2019

This paper deals with the problem of the efficient application of the series active filter in conditions of power supply systems of oil production enterprises with non-linear load and voltage dips. The mathematical model of the power supply system of oil production enterprise with the connected series active filter is developed. The control system for the series active filter with usage of the phase transformations, symmetrical components and frequency-controlled pulse-width modulation of IGBT control pulses is developed and proved. Based on the modelling results, the analysis of the efficiency of power quality indicators’ correction by means of the series active filter is carried out. The dependence of the voltage total harmonic distortion factor from the rated power of the output transformer of the series active filter is obtained.
Identification of interturn faults in power transformers by means of generalized symmetrical components analysis
Authors: Ivanchenko Daniil , Smirnov Artem
Published: December 2019

The paper deals with experimental identification of transformer internal faults, an important factor in reliability and sustainability of power supply systems. Task of identification of transformer internal faults requires increasing sensitivity of relay protection by calculation of components most sensitive to interwire faults from transformer current. In order to study internal faults in transformer, the model in Simulink MATLAB was developed on the basis of transformer constitutive equations. Transformer with short circuited wires was simulated as a multiwinding transformer. We provide the calculation of transformer parameters. Model was applied for analysis of transients in power transformers, such as interwire fault, transformer inrush, and fault in transformer connections. Analysis of power transformer internal faults by means of time-dependent symmetrical components of currents is provided. These symmetrical components were calculated for the first harmonic of current by means of discrimination of firs harmonic by low-pass filter and compensating elements implementing phase shift. Described method allows calculation of symmetrical components during transient and under non-sinusoidal conditions. Simulation results showed the advantage of instantaneous symmetrical components of other direct values. Those components were implemented in relay protection algorithms for identification of internal faults in transformers.
The impact of innovative technologies on consumers in the power supply market
Authors: Karuseva Nadezhda , Livshits Semen , Kotsubinski Andrew , Yudina Natalya , Novikova Olga , Tabakova Anastasiia
Published: December 2019

Service of supplying electricity to consumers in the Russian Federation (RF) is carried out based on power supply contract. Utilization of innovative technologies will allow to change the power supply service in the power-supply market. There is an opportunity to create unique powersuppling market approach. With implementation of “Smart meters” technology and Blockchains with “Smart Contract” functionality. The article describes innovative technologies and examines examples of their successful implementation in foreign countries. Article will also talk about tools that are required to replace old service with a new power supply system, based on innovative technologies that include small-scale renewable energy generation.
Increasing the energy efficiency of an enterprise by point compensating of power quality distortions
Authors: Zamyatin Egor , Voytyuk Irina , Zamyatina Elena
Published: December 2019

The cost of any product includes the cost of electrical energy in its production. Enterprises use various methods to reduce the cost of electric energy. One of the most common methods is to reduce the loss of active power in the distribution network of an enterprise. This is achieved by compensating for distortions in the power quality of electrical energy using compensating devices. The method presented in the article offers point compensation of distortions in the power quality indicators of electric energy. Point connection of compensating devices allows their small number to be used. But, at the same time, a greater effect is achieved. The connection points of compensating devices are determined by the developed method. The method includes three stages: collecting data on consumers of electric energy at an enterprise and on the topology of the distribution electric network, analyzing the results obtained using the developed algorithm, and determining connection points using the Pareto method. Also, the developed method was compared with the classical ones according to the criterion of the ratio of implementation costs to the effect of its application.
On possibility of replacement of saturated steam with hot water at circulating heating of fuel oil
Authors: Petrushchenkov Valery , Shcheglov Michail
Published: December 2019

Circulating heating of fuel oil in railway tanks is performed, as a rule, with the help of saturated steam by preparing a heating flow of fuel oil with a temperature of about 80...90°C. For the operation services of fuel oil storages, it is interesting to consider replacing steam with hot water. The behavior of the existing system of circulating heating of fuel oil of M100 brand when changing the heating medium for the heater of fuel oil flow in the form of a plate heat exchanger is considered. The initial temperature of hot water is assumed to be equal to the design temperature of 115°C in the steam-fuel heat exchanger. The values of the thermal capacity of the heater flow of fuel oil, fuel oil consumption, flow rate and the temperature of the heating water flow at the outlet of the heat exchanger are defined depending on the temperature of the heated fuel oil in the range of 80...90°C. Reducing the temperature of fuel oil at the outlet of the heat exchanger from 90 to 80°C allows to increase its capacity by 30.1%, that is, to accelerate the heating of fuel oil in the tank and reduce the time of its discharge.
High-temperature service life tests of full-size thermosyphons
Authors: Balunov Boris , Egorov Mikle
Published: December 2019

During past two decades, at temperature 240-265°C, resource tests were carried out on 19 thermosyphons of full-scale sizes: 45х4 mm in diameter, 4.92 m in length. The thermosyphons were prepared with varying preliminary surface treatment methods, composition of the aqueous solution to be poured into the thermosyphons, location of titanium chips in the perforated capsules under the lid of the thermosyphons. With a period of 1 to 3 years, thermosyphons were removed from testing system for 30 hours to control the vacuum by thermal method that does not require depressurization. At the last control experiment, four thermosyphons are depressurized for the following purposes: to check the condition of their internal surface in different zones along the length; for the chemical analysis of the aqueous solution poured from them; to determine the structure and characteristics of the mechanical properties of the thermosyphon metal. The main aim of the tests is to justify maintaining the structure and mechanical properties of the metal for a long time, keeping a vacuum of 90-95% inside the thermosyphon, ensuring high heat transfer characteristics of the boiling operating mode of thermosyphons.
The hydro-seeding and concrete anchors as a method for preventing damage to district heating network by local landslides
Authors: Chicherin Stanislav , Junussova Lyazzat , Junussov Timur
Published: December 2019

To prevent rain from eroding the sides of the trench we have developed a method of spraying them with hydro-seed. The homemade solution contains water, soil, mulch and a special blend of local grass seed. The mixture containing the blend of seeds enhances the soil to give it some strength and minimize the erosion. Another option is using concrete anchors instead of steel ones, which are supposed to increase the rigidity of a district heating (DH) network. The paper further visualizes the process with the materials required for each step. We constructed the equation in order to estimate net present value depending on the capital costs of the construction, the time of the cash flow, and the discount rate. In case of concrete anchors, the NPV of the project is negative. However, in case of hydro-seeding, the income provided by avoiding penalties becomes bigger than initial costs in the very first year of the project life span. From the comparison of two NPV profiles, the model combining the concrete anchors and the hydro-seeding can save up to 20% of investments compared to the conventional DH line. Results show that although then capital costs are increased by up to 24%, investment payback for DH network can be reduced to 12 years while life span can be increased by up to 30 years.
Development of mathematical model of Universal modeling method for centrifugal compressors calculation
Authors: Galerkin Yuri , Drozdov Aleksandr , Solovyeva Olga , Kabalyk Kirill
Published: December 2019

The heart of the Universal modeling engineering method is the physical model that is based on flow visualization and measurements inside rotating impellers. The experience of its application allowed finding ways of mathematical model development. The loss of a head is a function of flow gradients along a surface and along a normal to it. Necessary calculations were 1-D in the previous models. Quasi-three-dimensional approach is applied in the new model. A new loading factor model was applied. It determines characteristics by the angle of inclination and the value of the loading factor at zero flow rate. This made it possible to abandon the choice of empirical coefficients. A new loss of head model in a vaneless diffuser based on the results of CFD calculations generalization is used. The new model allowed abandoning a number of empirical coefficients of the mathematical models. Identification of the new mathematical model by the characteristics of model tests of centrifugal compressor stages was made. The efficiency calculation accuracy was sufficient for the engineering method.
Issues of gas dynamic characteristics modeling: a study on a centrifugal compressor model stage
Authors: Borovkov Aleksey , Voinov Igor , Galerkin Yuri , Nikiforov Aleksandr , Nikitin Maksim , Solovyeva Olga , Kabalyk Kirill
Published: December 2019

The paper presents the results of CFD-calculations of a centrifugal compressor stage with a high-pressure 3D impeller and a vaneless diffuser. The stage was designed by Prof. A. M. Simonov in the Problem Laboratory of Compressor LPI according to the following design parameters: flow rate coefficient 0.080, loading factor 0.74, and the relative Mach number 0.78. Two design grids were used: 2.4 and 4.4 million cells for the sector with one blade. The entire stage was calculated with a sparser grid. Special “Stage” interface conditions are used to interface the gas-dynamic parameters at the boundary regions. The SST turbulence model was used in the calculations. The results of efficiency characteristics and work coefficient comparison showed the following: in design flow rate all three variants of the calculation overstate the loading factor by 14.3%; the calculated characteristics of polytrophic work coefficient in the staging of 360 degrees are closest to the experimental characteristics, but the absolute value is greater than 12% at a flow rate coefficient of 0.085; the maximum calculated efficiency of a stage (the circle of 360 degrees) is almost equal to the measured maximum efficiency.
Method for measuring locomotive diesels characteristics for environmental monitoring tasks
Authors: Chernov Andrey , Chupiy Dmitry , Butakova Maria
Published: December 2019

A method for measuring diesel engines characteristics based on recording the irregularities of time parameters of the crankshaft rotation is proposed. We demonstrate that the change of diesel engines characteristics significantly affects the established norms and limit values of engine emissions of pollutants and harmful substances. The ways of improving the environmental characteristics of diesel engines, including change of fuel composition by adding mixtures are considered. A method of control of the diesel engine parameters consisting in measuring the instantaneous values of the speed of the crankshaft rotation and assessing the deviations of these parameters from normal values has been proposed. The method is implemented in the form of procedures including data collection from sensors installed on the engine, data filtering, and their characteristic analysis. An autonomous measuring device based on the microcontroller has been developed with the help of which data has been collected from the sensors of the 16-cylinder turbocharged engine. We have carried out experiments on process data that determine possibly faulty engine elements that worsen its environmental parameters.
Contamination effects study in the centrifugal compressor flow stage by means of numerical simulation methods
Authors: Aksenov A.A. , Kozhukhov Yu.V. , Lebedev A.A. , Petrov A. Yu. , Nguyen Minh Hai
Published: December 2019

At the moment there is no effective way to clean the flow of the turbine unit, which is justified from an economic point of view. It is important to understand how deposits affect compressor performance and the need to clean out contaminants. In the available literature, such studies are not described. The computational model of a stage domain for the study includes the following elements: inlet pipe, impeller, bladeless diffuser, swivel elbow, backward guide apparatus, outlet pipe. For calculations, the computational fluid dynamics methods in the Ansys software package were used. A numerical experiment was carried out in six mass flow rate variants, two impeller revolutions variants, and three different sediment thicknesses in the flow part variants. Based on the numerical experiment results, the calculated machine operating modes characteristics are constructed. The analysis revealed that the studied deposits cause a drop in the stage characteristics by 1.5-2%. Losses in the stage increase proportionately to the thickness of deposits in the compressor flow part.
Analysis of the statistical correlation between the estimated value of individual risk and the hazard class of a hazardous production facility in the Russian Federation
Authors: Byzov Anton , Pak Anastasia , Kuznetsova Darya , Ostapenko Galina
Published: December 2019

This article describes industrial safety procedures that take into account a risk-based approach to industrial safety in the Russian Federation, and the specifics of their application. The analysis of 189 objects of I-IV hazard classes of LLC “Technical Environmental Consulting” (LLC “TEC”) was carried out and the statistical correlation between the estimated value of individual risk and the hazard class of a hazardous production facility was identified.