Periodic Mode Research Articles

Вывихи бедра после тотального эндопротезирования тазобедренного сустава

Цель исследования — анализ собственных наблюдений вывихов бедра после первичной тотальной артропластики тазобедренного сустава, идентификация предрасполагающих факторов и оптимизация программы реабилитации пациентов. Идентификация предрасполагающих факторов проведена на основании данных дооперационного клинико-рентгенологического обследования, интраоперационных наблюдений и анализа особенностей реабилитационного периода 844 пациентов, перенесших тотальную артропластику тазобедренных суставов. Вывихи после операции отмечены у 69 пациентов (7,56 %). Выделены следующие факторы: нарушение двигательного режима в раннем послеоперационном периоде; осевые деформации на уровне бедра, коленного сустава, голени и стопы, нарушающие двигательную и опорную функцию оперированной конечности. Необходимость в ревизионных вмешательствах на тазобедренном суставе по поводу повторяющихся вывихов была обусловлена недостаточной антеверзией ацетабулярного компонента. Планирование первичной артропластики, включая выбор имплантата и хирургического доступа, должно осуществляться с учетом общесоматического и психоэмоционального состояния пациента, локальных и системных биомеханических нарушений. В реабилитационном периоде необходим индивидуальный выбор программы восстановительного лечения.

MODELING OF DYNAMICS OF ELECTRODYNAMIC SPEAKER

This article discusses an electromechanical system in the form of an electrodynamic loudspeaker. To describe the dynamics of a loudspeaker, a finite-dimensional model with a given number of a finite number of independent mechanical and electrical parameters is used. Using the electromechanical analogy force - voltage and using the Lagrange-Maxwell equations, a closed system of two nonlinear differential equations of the second order of motion of the system is compiled. Using modern advances in computer technology, a number of numerical experiments were performed in the Mathcad system with varying values of the input parameters of the system, such as the mass of the moving coil, inductance, ohmic resistance, and graphs of the time variation of the coil movement and current strength were plotted. Phase portraits were also built. The movement of the system has the character of damped oscillations, and the phase portraits have a stable focus. The influence of the varied parameters on the period of damped oscillations and the transition of the system to the state of equilibrium is shown. The study was carried out for a nonlinear model without the use of asymptotic methods, which made it possible to exclude the methodological error of the solution. The model can exhibit complex dynamics. Having a mathematical model and a calculation program, it is possible to carry out further studies of the system under consideration, identifying the positions of stable and unstable equilibrium, modes of self-oscillations, defining areas of periodic and chaotic modes of different nature. The results obtained can be used in the development of technical devices capable of demonstrating complex behavior. Methodologically, the proposed material is interesting for undergraduate and graduate students specializing in electromechanics, in terms of teaching the principles of constructing and analyzing electromechanical systems.

Periodic modes in an automatic control system with a three-position hysteresis relay

We consider an automatic control system with a three-position hysteresis relay and a continuous periodic external perturbation. The existence theorem is established that provide domains in the space of system parameters, including the parameters of the relay and perturbation, to which periodic modes having a pass to saturation zones with given periods and a specified configuration of phase trajectories correspond.

Numerical Simulation of a Porous Plate Water Sublimator Working in the Periodic Mode and Theoretical Analysis of its Evaporation Process

Numerical Simulation of a Porous Plate Water Sublimator Working in the Periodic Mode and Theoretical Analysis of its Evaporation Process

The Energy Transition's Impact on the Accumulated Average Efficiency of Large Hydrogenerators

The energy transition is aimed to take advantage of the operational flexibility of hydropower to extend the integration of intermittent renewable sources. Consequently, the hydrogenerators will have to operate in regimes far away from their designed best-point operation. In order to accurately assess the impact, this paper presents a useful approach to determine the overall operating efficiency of synchronous generators under intermittent operation. An accumulated average efficiency (AAE) model is proposed and compared against an alternative approach; the weighted average efficiency (WAE) model. It is found that the WAE approach produces unrealistic low efficiencies when the generator operates in synchronous condenser mode (SCM) for long periods. In general, the AAE supersedes the WAE for all the different load distributions that were investigated. This was further illustrated by a worked example and by constructing more complex load distributions. A load distribution dominated by SCM yields a difference as high as 33.18 %, while an even distribution deviates 1.43 % in their respective efficiencies. Finally, a yearly on-site measurement of our studied 103 MVA generator's concentrated load distribution revealed a discrepancy of 0.67 %, which is a significant deviation considering what the operating regime would mean in terms of economic implications.

Distance education in the context of the COVID-19 pandemic Case of the Faculty of Sciences Ben M’Sick

In order to escape the spread of the coronavirus (COVID-19), qualified as a pandemic by the OMS, the suspension until further notice of courses in all schools and universities from Monday March 16, 2020. In this context and in order to ensure educational continuity and to diversify the possible alternatives, the Ministry of National Education, Vocational Training, Higher Education and Scientific Research to decide to switch from face-to-face teaching to distance by allowing teachers to communicate directly with their students and to organize distance learning courses (Platforms, Video clips, Live, Classroom, etc.). This article describes the experience of the faculty of sciences Ben M’Sick, in education remotely in the age of pandemic Covid-19. Our interest is to assess the quality of distance education within the Faculty of Sciences Ben M’sick to ensure the continuity of educational activities and the necessary teaching and to complete the academic year. In this context, our contribution aims to show the different approaches adopted by the Faculty of Science Ben M’Sick and know the impressions and the opinions of teacher-researchers on this distance education mode in this pandemic period.

不同水分条件下杨树-玉米复合系统凋落物分解特性

PDF HTML阅读 XML下载 导出引用 引用提醒 不同水分条件下杨树-玉米复合系统凋落物分解特性 DOI: 10.5846/stxb202104060884 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31960245）；甘肃农业大学公招博士科研启动基金项目（GAU-KYQD-2018-07）；甘肃农业大学学科建设基金项目（GAU-XKJS-2018-108，GAU-XKJS-2018-104） Litter decomposition characteristics of poplar-maize agroforestry system under different water conditions Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探讨水分变化对农林复合生态系统凋落物分解特性的影响，以河西走廊杨树（Populus）-玉米（Zea mays）凋落物为研究对象，设置正常水分（9200 m3/hm2，对照），轻度干旱胁迫（减少15%，7800 m3/hm2），中度干旱胁迫（减少30%，6400 m3/hm2）3种不同水分处理条件，采用分解袋法研究了不同水分条件下杨树叶和玉米秸秆的质量残留率、分解速率和养分含量变化特征。结果表明：（1）随着干旱胁迫的加剧，两种凋落物的质量残留率均增加，而分解速率降低。经过164 d的分解后，杨树叶和玉米秸秆的质量残留率分别为70.43%-77.49%、63.55%-68.29%。分析表明：水分和时间对各类型凋落物的质量残留率均有极显著的影响（P<0.001），但二者的交互作用不显著（P>0.05）；干旱胁迫显著降低了玉米秸秆的分解速率，但杨树叶的分解速率却只是在中度干旱胁迫下显著降低（P<0.05）。对于不同类型凋落物而言，分解速率表现为玉米秸秆>杨树叶。（2）两种类型凋落物的氮（N）残留率在分解过程中表现为降低的趋势，但随着干旱程度的加大，N的残留率增加，表明水分抑制了N的释放过程。分解164d后，同一类型凋落物不同水分条件下的N残留率均存在显著差异。对于同一水分条件下不同凋落物而言，玉米秸秆的N残留率最低，而杨树叶最高。总的来说，水分降低对干旱区农林复合系统内凋落物的分解和氮元素含量具有显著的抑制作用。 Abstract:Litter decomposition plays an important role in the carbon budget and nutrient cycling in terrestrial ecosystems, but the decomposition process and decomposition rate of litters were affected by environmental factors, especially the water condition. However, little attention has been paid to the effect of changing water condition at litter decomposition for the maize-poplar system in arid regions. Here the litters of poplar leaves and maize straws in the Hexi Corridor were selected as research objects, and there were three water treatments including normal water (9200 m3/hm2, CK), mild drought stress (irrigation reduced by 15%, 7800 m3/hm2), moderate drought stress(irrigation reduced by 30%, 6400 m3/hm2), which were designed in our experiment. The mass remaining, decomposition rate and nitrogen content for poplar leaves and maize straws were measured and analyzed under different water conditions using decomposing bag method, meanwhile the effects of water changes on the decomposition characteristics of two litter types were analyzed. The results showed that:(1) the mass remaining for two litter types were increasing with increasing drought stress, but the decomposition rates were decreasing. After 164 days of decomposition, the mass remaining for poplar leaves and maize straws litter were 70.43%-77.49%, 63.55%-68.29% under three water conditions, respectively. The analysis indicated that water and time extremely significant affected the mass remaining (P<0.001), but their interactive effects on mass remaining were not significant (P>0.05). Drought stress significantly reduced the decompoation rate of maize straws, but it was only significantly decreased under moderate drought stress for poplar leaves. For the different litter types, the decomposition rate of maize straw was higher than that of poplar leaf. (2) The N remaining of two litter types was decreasing trends in the decomposition process under three water conditions, this showed that the N remaining presented releasing mode in the study period, but the N remaining was increasing with increasing drought stress, it indicated that water reducing significantly inhibited the release process of N for the two litter types. After 164 days of decomposition, the N remaining had significant difference under three water conditions for the same litter, and the decomposition time also extremely significant affected N remaining, but the two interaction has no significant effect on N remaining. For the different litter types, the N remaining for maize straws was minimum and it was maximum for poplar leaves in the same water condition, this showed the N release of poplar leaf was greater than that of maize straw. As a whole, water reducing significantly inhibited the litter decomposition and N release for the two litter types in the agroforestry system in the arid region. 参考文献 相似文献 引证文献

An Advanced Satisfaction-Based Home Energy Management System Using Deep Reinforcement Learning

Home energy management (HEM) systems optimize electricity demand of appliances according to the price-based demand response (DR) programs. Undoubtedly, customer satisfaction is of such importance that if not taken into consideration, it prevents customers from participating in the DR. HEM systems suffer from high nonlinearity due to the variety of smart appliances and different criteria for customer satisfaction. In this paper, an advanced satisfaction-based HEM system using deep reinforcement learning is proposed to hourly schedule the controllable and time-shiftable appliances, including electric vehicle, air conditioner, and lighting system as controllable loads and washing machine, and dishwasher as time-shiftable loads. The proposed framework deploys a Deep Q-Network (DQN) method. Regarding customer dissatisfaction, this paper takes into consideration nonlinear precise functions. The Kano model for EV departure SoC, charging duration and lighting system satisfaction, desired temperature span for air conditioner, and the desirable operation period, waiting time, and consecutive mode of dishwasher and washing machine are taken into account. The proposed HEM system is applied to a smart home, and the results are compared with those of the Q-Learning algorithm. Numerical results prove the effectiveness of the proposed HEM system in reducing electricity cost and customer dissatisfaction, as well as the superiority of DQN over Q-Learning as well.

Investigation of the spatial motion of a body with distributed mass connected by an inextensible cable to a moving trolley

The article considers the spatial motion of a mechanical system where a heavy beam of a given mass and dimensions is suspended at one end by a weightless inextensible cable to a trolley, which can move along horizontal guides without resistance. The system has five degrees of freedom. Based on the apparatus of analytical mechanics and Lagrange equations, a mathematical model of the considered mechanical system in the form of a system of five nonlinear differential equations of the second order is obtained. The mathematical model is implemented in the form of a computer program that allows you to determine the coordinates (positions) of the beam at any time, build the trajectory of the center of mass, determine the kinematic characteristics of the movement, calculate the cable tension and determine its extreme value. Based on the numerical experiment, graphs and phase trajectories of these parameters are constructed, including the 3D trajectory of the center of mass of the beam. The system can show quite complex dynamics depending on the initial conditions, as evidenced by the results of numerical calculations. Under certain conditions, chaotic behavior of the system is possible. Having a mathematical model and a calculation program, it is possible to conduct further studies of the system under consideration, revealing the positions of stable and unstable equilibrium, modes of self-oscillations, revealing areas of periodic and chaotic modes, bifurcations, and so on.

Self-Trapping Phenomenon in an Exciton-Polariton System When the Lower Polariton Branch is Pumped by Two Laser Pulses with Close Frequencies

The dynamics of exciton-polariton states in a semiconductor microcavity is studied under pumping of the state corresponding to the lower polariton branch, taking into account single-mode and intermode elastic polariton-polariton interactions. In this case, pumping is carried out by two laser pulses with close frequencies. It is shown that at the initial phase difference equal to theta0=π/2, the regime of quantum self-trapping of exciton-polaritons is observed. Periodic and aperiodic modes of evolution of a system of quasiparticles are obtained. Keywords: exciton-polariton states, quantum self-trapping, periodic and apeiodic regimes.

Dynamic analysis of a new aquatic ecological model based on physical and ecological integrated control.

Within the framework of physical and ecological integrated control of cyanobacteria bloom, because the outbreak of cyanobacteria bloom can form cyanobacteria clustering phenomenon, so a new aquatic ecological model with clustering behavior is proposed to describe the dynamic relationship between cyanobacteria and potential grazers. The biggest advantage of the model is that it depicts physical spraying treatment technology into the existence pattern of cyanobacteria, then integrates the physical and ecological integrated control with the aggregation of cyanobacteria. Mathematical theory works mainly investigate some key threshold conditions to induce Transcritical bifurcation and Hopf bifurcation of the model (2.1), which can force cyanobacteria and potential grazers to form steady-state coexistence mode and periodic oscillation coexistence mode respectively. Numerical simulation works not only explore the influence of clustering on the dynamic relationship between cyanobacteria and potential grazers, but also dynamically show the evolution process of Transcritical bifurcation and Hopf bifurcation, which can be clearly seen that the density of cyanobacteria decreases gradually with the evolution of bifurcation dynamics. Furthermore, it should be worth explaining that the most important role of physical spraying treatment technology can break up clumps of cyanobacteria in the process of controlling cyanobacteria bloom, but cannot change the dynamic essential characteristics of cyanobacteria and potential grazers represented by the model (2.1), this result implies that the physical spraying treatment technology cannot fundamentally eliminate cyanobacteria bloom. In a word, it is hoped that the results of this paper can provide some theoretical support for the physical and ecological integrated control of cyanobacteria bloom.

Явление самозахвата в системе экситон-поляритонов при накачке нижней поляритонной ветви двумя лазерными импульсами с близкими частотами

The dynamics of exciton-polariton states in a semiconductor microcavity is studied under pumping of the state corresponding to the lower polariton branch, taking into account single-mode and intermode elastic polariton-polariton interactions. In this case, pumping is carried out by two laser pulses with close frequencies. It is shown that at the initial phase difference equal to θ_0=π⁄2, the regime of quantum self-trapping of exciton-polaritons is observed. Periodic and aperiodic modes of evolution of a system of quasiparticles are obtained.

ОСОБЛИВОСТІ ГЕНЕРАЦІЇ ВЕЛИКОМАСШТАБНИХ ЗБУРЕНЬ В ІОНОСФЕРІ ПІД ДІЄЮ МОНОІМПУЛЬСНОГО ТА ПЕРІОДИЧНОГО РАДІОВИПРОМІНЮВАННЯ НАГРІВНОГО СТЕНДА

Subject and Purpose. Considerable attention has traditionally been given to the interaction of high-power radio-frequency emissions with the ionosphere. The great many physical effects taking place within the limits of a powerful (heating) facility’s antenna pattern are subjected here to a thorough and detailed analysis. Also, the application of high-power radio emissions provides a convenient means for studying subsystem coupling in the Earth-atmosphere-ionosphere-magnetosphere system, as well as of generation and propagation of disturbances well beyond the antenna pattern of the transmitter. The present paper has been aimed at analyzing the features revealed by the large-scale ionospheric disturbances as these are generated under the impact of either monopulse or periodic radio-frequency emissions from an HF heating facility. Methods and Methodology. In the course of the experiments, the ionosphere was affected with high power radio frequency emission from the heating facility Sura. The disturbances were diagnosed at a distance of 960 km from the heater, with the aid of a vertical incidence Doppler radar. Results. It has been found that through the period of minimal solar activity the ionospheric disturbances observable at a range about 103 km from the heater did arise as the effective radiated power of the latter approached to 25 MW. The duration of the ionospheric response to the impact of an incident monopulse was equal to the length of that latter, while the quasi-periodic variations shown by the Doppler frequency shift just started to appear. The apparent horizontal speed of the propagating disturbances was found to vary from about 300 m/s to 420 m/s. Note that speed to increase at higher altitudes. The periodic mode of heater operation was accompanied by generation of quasi-periodic disturbances in the electron density, of relative amplitudes about 1% and periods close to the Brunt–Väisälä period. Conclusions. The basic features of Doppler spectrum variations, contained in the signals from a diagnostic radar, have been identified in connection with high-power HF radiation incident on the ionosphere

Capturing Individual Hydrogen Bond Strengths in Ices via Periodic Local Vibrational Mode Theory: Beyond the Lattice Energy Picture.

Local stretching force constants derived from periodic local vibrational modes at the vdW-DF2 density functional level have been employed to quantify the intrinsic hydrogen bond strength of 16 ice polymorphs, ices Ih, II, III, IV, V, VI, VII, VIII, IX, XI, XII, XIII, XIV, XV, XVII, and XIX, that are stable under ambient to elevated pressures. Based on this characterization on 1820 hydrogen bonds, relationships between local stretching force constants and structural parameters such as hydrogen bond length and angle were identified. Moreover, different bond strength distributions, from uniform to inhomogeneous, were observed for the 16 ices and could be explained in relation to different local structural elements within ices, that is, rings, that consist of different hydrogen bond types. In addition, criteria for the classification of hydrogen bonds as strong, intermediate, and weak were introduced. The latter was used to explore a different dimension of the water-ice phase diagram. These findings will provide important guidelines for assessing the credibility of new ice structures.

Toward robust and practical interband cascade laser frequency combs: A perspective

Multimode emission from a semiconductor laser can sometimes take the form of a low-noise frequency comb with equidistant separation between the modes. Two general types of “passive” comb operation have been explored experimentally: (1) the periodic short-pulse mode achieved by intracavity mode locking, usually obtained by incorporating a saturable absorber section into the cavity, and (2) the so-called frequency-modulated (FM) mode in which the output intensity can vary within wide bounds but does not completely turn off between pulses, and the instantaneous frequency is linearly chirped over a round trip. The FM mode sometimes manifests as a “sparse” harmonic state, with individual modes spaced by multiples of the cavity free spectral range. This Perspective reviews the current understanding of these modes, along with the conditions under which they may arise in practical devices. We then consider in detail the case of type-II mid-infrared interband cascade laser (ICL) frequency combs. Our simulations clarify the roles of carrier dynamics and group velocity dispersion and identify design modifications that may substantially improve the device performance. We find no fundamental roadblocks to the development of practical mode-locked ICL frequency combs that emit short pulses with broad spectral bandwidth for dual comb spectroscopy and other applications, alongside the FM combs that have already been demonstrated experimentally.

Construction of mathematical modelling of a population of microalgae

This article devoted to the development of the mathematic model of the technological process of the chlorella cultivation process, its features and solving of this mathematic model. The Exponential growth of microalgae population under conditions of unlimited nutrient resources and population space proceeds at a rate proportional to the number of species of predominant cells and is described by the differential equation. In the presence of several inhibitors, specific velocity equations with the number of inhibitors can be used, but, as a rule, there are practically no elements acting as inhibitors in the cultivation of Chlorella microalgae. The modeling of this particular class of objects did not take into account the effect of inhibitors on the growth of microalgae. The consumption of nutrients to support the life of microalgae is described by the differential equation. In the course of this work, the processes of cultivation of microalgae were brought together into a system of equations. As a result, a system of differential equations of the technological process of Chlorella cultivation was obtained. Thus, the obtained system of equations describes the process of cultivation of microalgae and its technological process, implemented in a periodic mode.

Mode transformations of vortex shedding behind a sphere with the effect of Lorentz force

In this paper, the modes of vortex shedding in the wake of a stationary sphere with the Lorentz force, which can be generated by the actuators in weakly conductive fluids and is parallel to the sphere surface, are numerically investigated at Re = 300. The relations among the wake structures, the vorticity distribution, and the motions of the rear stagnation point and the separation point are discussed before and after the application of Lorentz force. From this, the mechanism of mode transformations in the sphere wake is revealed. The results indicate that the fluid near the sphere surface is accelerated with the application of Lorentz force. The rear stagnation point and the separation point move rearward and become steady. Therefore, the vorticity on the rear surface of the sphere gradually decays and becomes steady, which leads to the periodic shedding mode of hairpin vortex replaced by the steady double-thread wake structure. Moreover, the wake structure varies with the interaction parameter N of the Lorentz force. When the Lorentz force is relatively small (N = 0.04), the vibration amplitude of hairpin vortex is weakened, and the vortex heads disappear with vortex legs and necks left. The wake is still periodic due to the hairpin vortex shedding. As N increases to 0.08, the hairpin vortex is suppressed completely, while the double-thread wake appears. The wake is steady due to the suppression of the hairpin vortex shedding. As N further increases to 0.20, a spanwise vortex ring is formed around the double-thread wake.

Determination of the effective operating hours of the intermittent lighting system for growing vegetables

Around the world, one of the key challenges is the provision of food for a growing urbanized population. A vertical farming system will help solve this problem. Vertical farming in a controlled environment provides 4-6 times higher yields per unit area, but requires more electricity. The most economical light sources are light-emitting diodes but it is important to determine the rational operating mode of the lighting system. The aim of the study was to determine the specific operating hours of the intermittent lighting system to reduce the cost of electricity consumption when growing vegetables in vertical farming in a controlled environment. Continuous and periodic modes of operation of the lighting system with a total operating time of 16 hours per day were considered. In Russia, there are six price categories for consumed electricity. Research has shown that price level II is economically viable. and a rational operating mode: 8 hours of light/4 hours of darkness, etc. Thus, the intervals of operation of the lighting system are 11.00-19.00 and 23.00-7.00. The study of this regime for microgreening of Mitsun head cabbage showed that the productivity of the plants was preserved, since the length of the leaves did not change.

Using Ecological Momentary Assessments and Fitbit Data to Examine Daily Associations Between Physical Activity, Affect and Alcohol Cravings in Patients with Alcohol Use Disorder.

Preliminary studies show that structured physical activity (PA) interventions can reduce negative affect and alcohol use in patients recovering from alcohol use disorder (AUD). The current study tested whether the association between PA, affect, and alcohol cravings can be observed in patients' natural environments (i.e., without a structured intervention) as well. Twenty-five participants with AUD completed 3weeks of ecological momentary assessment (EMA) monitoring and wore Fitbit devices to measure physical activity directly after discharge from partial hospitalization treatment for AUD. PA was operationalized as total steps and consecutive 10-min bouts of moderate-intensity exercise (100 steps/minute). Only 56% of participants engaged in any bouts of moderate-intensity physical activity throughout the 3-week study period (mode = 1 bout), and participants logged an average of 8183 steps/day (SD = 5560). Daily steps were associated with a higher positive affect and lower alcohol cravings, and with higher positive affect the next day, but the effects were very small. No relationships were observed between PA and affect or alcohol cravings at the hourly level except a random effect signifying that bouts of PA were either positively associated or not associated with negative affect in the next hour for different participants. Overall, results suggest that naturalistic PA may be beneficial for a small subset of patients in recovery from AUD, but the majority did not engage in regular exercise or experience improvements in affect and cravings as a result of PA.

Impact of Periodic Polarization on Groundwater Denitrification in Bioelectrochemical Systems.

Nitrate contamination is a common problem in groundwater around the world. Nitrate can be cathodically reduced in bioelectrochemical systems using autotrophic denitrifiers with low energy investment and without chemical addition. Successful denitrification was demonstrated in previous studies in both microbial fuel cells and microbial electrolysis cells (MECs) with continuous current flow, whereas the impact of intermittent current supply (e.g., in a fluidized-bed system) on denitrification and particularly the electron-storing capacity of the denitrifying electroactive biofilms (EABs) on the cathodes have not been studied in depth. In this study, two continuously fed MECs were operated in parallel under continuous and periodic polarization modes over 280 days, respectively. Under continuous polarization, the maximum denitrification rate reached 233 g NO3--N/m3/d with 98% nitrate removal (0.6 mg NO3--N/L in the effluent) with negligible intermediate production, while under a 30 s open-circuit/30 s polarization mode, 86% of nitrate was removed at a maximum rate of 205 g NO3--N/m3/d (4.5 mg NO3--N/L in the effluent) with higher N2O production (6.6-9.3 mg N/L in the effluent). Conversely, periodic polarization could be an interesting approach in other bioelectrochemical processes if the generation of chemical intermediates (partially reduced or oxidized) should be favored. Similar microbial communities dominated byGallionellaceaewere found in both MECs; however, swapping the polarization modes and the electrochemical analyses suggested that the periodically polarized EABs probably developed a higher ability for electron storage and transfer, which supported the direct electron transfer pathway in discontinuous operation or fluidized biocathodes.