Operation Mode Changes Research Articles

Structural Modifications for Tuning Performance and Operational Modes in n-Type Organic Electrochemical Transistors.

Organic mixed ionic-electronic conductors (OMIECs) are crucial in defining the operational modes and performance of organic electrochemical transistors (OECTs). However, studies on the design and structure-performance correlations of small-molecule n-type OMIECs remain scarce. Herein, we designed and synthesized a series of naphthalene diimide (NDI)-based n-type small molecules by extending π-conjugation and increasing the number of electron-withdrawing groups, achieving performance optimization and even changes in operational modes through structural regulations. OECTs based on 4Br-NDI-3EG exhibit a low threshold voltage of -0.022 V, which is the lowest reported for n-type channel materials to date. NDI-DTYA-3EG, synthesized through π-expansion of 4Br-NDI-3EG, maintains a low threshold voltage of -0.041 V and achieves 2 orders of magnitude improvement in electron mobility (1.04 × 10-2 cm2 V-1 s-1) owing to its mixed edge-on and face-on orientation. Specifically, by further increasing the number of electron-withdrawing groups, NDI-DTYM-3EG attains a sufficiently low LUMO energy level (-4.51 eV), enabling a spontaneous reduction in 0.1 M NaCl solution without external bias, thereby achieving self-doping. Consequently, it exhibits n-depletion-mode characteristics with a transconductance value of 287 μS. Moreover, devices made with NDI-DTYM-3EG show exceptional stability, retaining 98% of the initial drain current after 150 min operation. These results provide insights into the understanding and design of n-type mixed ionic-electronic conductor materials.

Cell clone selection-impact of operation modes and medium exchange strategies on clone ranking.

Bioprocessing has been transitioning from batch to continuous processes. As a result, a considerable amount of resource was dedicated to optimising strategies for continuous production. However, the focus has been on developing a suitable and scalable perfusion strategy with little attention given to the selection of optimal cell clones. Cell line development and lead clone selection are critical to bioprocess development. The screening and selection process is typically performed in stages. Microwell plates (MWP) are used to narrow down the number of clone candidates, which will undergo further selective screening in progressively larger small-scale bioreactors (12mL-3L) to identify the top clone for GMP production. Perfusion mode is typically applied at bench-scale for optimisation purposes, while process development and cell clone screening studies at mL-scale still commonly use fed-batch methods. The change of operation mode from bolus feeding to perfusion with a regular exchange of medium, leads to questions regarding the reliability and fit of initial clone selection. Is the early-stage clone ranking impacted by the discrepancy in the operation mode, and does this potentially result in the exclusion of cell clones suitable for perfusion processes? To address this question, we evaluated various CHO cell clones expressing two antibody products using MWP methodologies in fed-batch and semi-perfusion mode. We assessed growth, metabolic, and productivity performance, and ranked cell clones using two different strategies. The first strategy evaluated clones based on a single parameter: the cell-specific productivity (qP). The second considered a collection of multiple parameters using the metric of the Manufacturability index (MICL). Both ranking strategies showed an impact of operation mode and perfusion rate on the clone ranking. Notably, depending on the chosen operation mode, different sets of candidate clones might have been selected for further, more extensive screening. Additionally, we evaluated the reproducibility of our results demonstrating consistency in cell clone growth performance and ranking.

A new approach to instantaneous power based control of DFIG using active disturbance rejection control

A new approach to instantaneous power based control of DFIG using active disturbance rejection control

КОНЦЕПЦІЯ ПОБУДОВИ ГІБРИДНОЇ СИСТЕМИ КЕРУВАННЯ МІКРОГІДРОЕЛЕКТРОСТАНЦІЄЮ

Methods of increasing the energy efficiency of micro-hydroelectric power plants are considered in the work. A new hy-brid concept of building a control system is proposed, which combines classical control laws and fuzzy logic. This makes it possible to improve the quality of the regulation of the parameters of the generated electricity regardless of changes in network operation modes and external conditions. It is shown that the use of hybrid filters will allow to in-crease the electromagnetic compatibility and, as a result, the energy efficiency of the system as a whole. References 12, figures 3.

Minimization of noise of the precision cooling system in the dynamic mode of the electronic apparatus

The design of a floor-standing telecommunication cabinet is considered. Air movement inside the cabinet is carried out in the vertical direction due to the simultaneous operation of supply and exhaust ventilation units. The reasons for the increased noise in the dynamic mode of operation are analyzed. The cabinet design is regarded as a mechanical and acoustic resonator with a heat-sensitive element that requires precision cooling. Constant airflow ensures constant element temperature. When the thermal power changes in a dynamic mode of operation, a change in the performance of ventilation units is required. This explains the occurrence of various resonances in the structure and, as a result, increased noise. Airflow consistency can be achieved using alternative operating modes of the supply and exhaust ventilation units. Analytically, families of isothermal supply voltage curves of ventilation units for laminar air movement have been constructed. The noise level's mathematical dependence on the fans' supply voltage is compiled, considering the resonances in the cabinet structure. Noise characteristics corresponding to isothermal voltage curves have characteristic minima. The transition between the isothermal supply voltage curves along the minimum noise trajectory controls the ventilation units. This method's possibility of minimizing noise has been confirmed analytically and experimentally. Keywords: electronic device, heat-sensitive element, ventilation unit, air flow, dynamic mode, isothermal stress curve, resonance, minimization, trajectory, noise.

Research on solar-assisted ejector-enhanced air source heat pump cycle with dual-pressure condensation

ABSTRACT A novel solar-assisted ejector-enhanced air source heat pump cycle with dual-temperature condensation (SEASHP-DC) is proposed in this study. Two types of hot water with different temperatures can be supplied for heating. By using solar energy and ejector, the COP of the system can be improved in cold regions. The cycle can change operation mode according to the solar radiation intensity, which can turn into a conventional heat pump cycle with dual-pressure condensation (CHP-DC) when the solar radiation intensity is low or at night. The performance of the proposed cycle is simulated with different refrigerants (R134a, R1234yf, and R1234ze(E)). Results show that the R1234ze(E) is an ideal substitute for the R134a. The performance of the SEASHP-DC is investigated and compared with that of the CHP-DC under the given condition. Compared with the CHP-DC, a considerable improvement of 55.9% in COP at a heating capacity ratio equal to 1.5 is reached by the SEASHP-DC. The largest exergy destruction occurs at the solar collector due to the huge temperature difference between the solar collector and the environment. The feasibility of applying this system during the heating season is confirmed, with daily working hours ranging from 6 to 8 h.

Digital Operational Strategies in The Post-Pandemic Era for Travel Companies: A Case Study of Ctrip

The epidemic’s impact has caused the tourism industry to face major challenges and changes in the post-epidemic era, in which the digital operation model has become the key to driving recovery and innovation. Taking Ctrip as an example, this study provides an in-depth analysis of the changes in the digital operation mode of tourism enterprises in the post-epidemic era. Firstly, the context and situation of Ctrip’s activities have changed in the digital environment, expanding the online business space and strengthening the interaction between the company and consumers. Second, the digital environment has changed corporate and consumer behavior from competition to cooperative symbiosis while triggering the socialization and personalization of consumer behavior. In addition, Ctrip’s travel products have changed in the digital environment, with data analysis to tailor travel products for consumers. Practical applications of Ctrip’s digital operations, including user demand forecasting and product design optimization, are further discussed. It is concluded that digital operations are important in improving management efficiency, meeting consumer demand, pricing strategy, and risk control. However, digital operations face legal, protection, and risk issues that require further research and solutions. This study provides useful experiences and insights for developing digital operation modes in tourism enterprises.

ISOLATION OF HIGH PURITY PIPERYLENE

Piperylene is a valuable raw material component for petrochemical synthesis, perfumery and cosmetic products, and is used as a solvent for petroleum products in the production of synthetic rubbers and latexes, and in the paint and varnish industry. Piperylene in the form of a fraction is produced in the production of isoprene by the two-stage dehydrogenation of isopentane, where it is a secondary product of the main synthesis. Isolation of commercial piperylene of high purity will allow the production of a value-added product and expand the sales market. Currently, restrictions on the production of commercial piperylene are associated with the high content of an impurity – cyclopentadiene. Previous studies by the author showed the feasibility of extracting cyclopentadiene at the stage of obtaining the catalyzate of the second stage of isoprene dehydrogenation. Simulation of the technological scheme in the application program showed that, together, the extraction of cyclopentadiene by a chemical method and a change in the technological operating mode makes it possible to isolate piperylene with a content of 99.45 % wt and CPD equal to 0.0046 % wt.

Design and Application of Station Power Supply System for Lithium Iron Phosphate Battery Based on Power Exchange Operation

Based on the engineering application design and development of the power supply system of lithium iron phosphate battery pack in the operation and maintenance mode, this paper conducts the application research from four aspects of battery quantity selection, capacity calculation selection, battery management system design, battery pack modular design, etc. The design scheme of the lithium iron phosphate power supply system is formulated, and the matching battery management system is designed. A universal lithium iron phosphate battery module with an “N+1” redundant configuration is developed to improve the maintenance efficiency of the battery pack. It reliably supports the substation power changing operation and maintenance mode and ensures the reliability and operation safety of the substation power supply system.

Evaluation Method for Reverse Recovery Characteristics of Thyristors Based on Charge Measurement

The change of operation mode of the HVDC project causes a change of the external characteristic of the converter valve, and the reverse recovery characteristic of the thyristor inside the converter valve changes accordingly. Therefore, the reverse recovery charge measurement values of thyristors under different operating conditions cannot be directly compared, and the status of thyristors cannot be evaluated online. Therefore, a method of measuring the reverse recovery charge of series thyristor based on the turn-off voltage is presented in this paper. Then, the operation mode of the HVDC project is analyzed, and the external characteristics of the converter valve under different operation modes are discussed. Secondly, the external factors that affect the reverse recovery characteristics of thyristors are analyzed essentially, and the relationship between the external factors and the external characteristics of the converter valve is discussed. A reverse recovery charge model considering external factors is established, and a method to reduce the error is proposed. Finally, the reverse-recovery charge normalization coefficient is derived for the normalization of the measured values in different working conditions. Based on the charge online measurement method and the normalization method proposed in this paper, the reverse-recovery characteristic evaluation method of the thyristor is proposed, and the evaluation steps are introduced.

NOx emissions prediction for MSWI process based on dynamic modular neural network

NOx emissions prediction for MSWI process based on dynamic modular neural network

Emulation of Integrated Starter/Generator Using Power Electronic Devices

Integrated starter/generator (ISG) is an important facility in transportation power systems. Using power electronics based motor emulator (ME) to test the motor controller is an emerging technique to optimize the design process of the motor drive system. In this paper, an ME is designed to test the control system of ISG in the full operation process. Facing the challenge of dual-mode emulation, a voltage-in-voltage-out interface is proposed to handle the causality problem caused by operation mode change during the starting/generating process. The LCL interface with predictive voltage closed-loop control is proposed to ensure emulation accuracy. A prototype of ME has been developed. The experiment has been done to validate the performance of the emulator, showing that the proposed method can be used to test the ISG controller in full operational mode with accuracy and fast dynamics.

Clinical effects of robot-assisted esophageal hiatal hernia repair and laparoscopic esophageal hiatal hernia repair: a retrospective comparative study

Objective: To analyze the short-term clinical effects of robot-assisted and laparoscopic repair of the hiatal hernia. Methods: The clinical data of 56 patients underwent minimally invasive hiatal hernia repair from January 2021 to January 2022 in the Department of Minimally Invasive Surgery, Hernias and Abdominal Wall Surgery, People's Hospital of Xinjiang Uygur Autonomous Region were retrospectively analyzed. There were 32 males and 24 females, aging (59.7±10.7) years (range: 28 to 75 years). All patients were divided into laparoscopy group (n=27) and robot group (n=29) according to surgical procedures. Perioperative conditions, hospital stay, and improvement in symptoms before and after surgery were compared between the two groups by the t test, Wilcoxon rank-sum test and χ2 test. Results: All surgical procedures were successfully completed, without conversion to laparotomy or change in operation mode. There were no serious complications related to the operation. The intraoperative blood loss of the robot group was less than that of the laparoscopic group (M (IQR)): (20 (110) ml vs. 40 (80) ml, Z=-4.098, P<0.01). The operation time ((111.7±33.6) minutes vs. (120.4±35.0) minutes, t=-0.943, P=0.350) and hospitalization time ((3.9±1.4) days vs. (4.7±1.9) days, t=-1.980, P=0.053) of the robot group and the laparoscopic group were similar. Follow-up for 12 months after the operation showed no postoperative complications and recurrence. The score of the health-related quality of life questionnaire for gastroesophageal reflux disease in the robot group decreased from 10.8±2.8 before the operation to 6.5±0.6 after the operation, and that in the laparoscopic group decreased from 10.6±2.1 before the operation to 6.3±0.6 after the operation. There was no difference in the influence of different surgical methods on the change in score (t=0.030,P=0.976). Conclusion: Compared with laparoscopic repair of the hiatal hernia, robot-assisted hiatal hernia repair has the advantages of less bleeding, rapid postoperative recovery and good short-term effect.

A statistics-based review on island detection methods in microgrids: Overall investigation and state-of-the-art

AbstractIn this paper, a comprehensive statistics-based review of islanding detection methods (IDMs) in microgrids (MGs) is presented. Islanding detection is the situation of isolating the MG from the main grid whether programmed as a result of load managing purposes or un-programmed due to the occurrence of faults. Islanding detection is a vital issue in MG's analyses due to the prevention of subsequent protection problems in the power system. In other words, when the MG's operation mode changes, the current passing through the protective devices changes subsequently and the protection system should be able to adapt the new settings to the protective devices. So, IDMs are vital for electrical engineers to overcome the abovementioned protection issue. This review paper surveys the existing literature in IDMs by concentration on total publications, type of publications (journal, conference paper, or book), five authors with the highest number of publications (including the affiliations), and five most published sources. Also, the five most cited publications and state-of-the-art IDMs are investigated in detail, utilizing some known and novel categorizations. This paper will be useful for the MG's researchers to know the most desirable IDMs, especially in recent years, and provides an insightful overview for future studies.

Adaptive additional current-based line differential protection in the presence of converter- interfaced sources with four quadrant operation capability

Adaptive additional current-based line differential protection in the presence of converter- interfaced sources with four quadrant operation capability

Taking the long view of the multinational

PurposeThis paper argues for the benefits to international business (IB) of taking a much longer view at the engagement by multinational enterprises (MNEs) with host locations.Design/methodology/approachThe authors showcase a project tracking the engagement by MNEs with Australia over the past two centuries. Extensive archival work has been undertaken to identify and document modes of entry, home countries, industries, operational modes and company types among the MNEs operating in Australia. The authors also describe the shifting nature of Australia as a host location.FindingsThe authors demonstrate the historical and ongoing diversity of ways in which MNEs interact with a host. They show that different organisational forms have prevailed over time, and that considerable operational mode changes can best be observed when a long lens is adopted. The authors show how these mode changes interact with host country dynamics, and also the broader context of the MNE and its altering strategies.Research limitations/implicationsThe authors urge IB scholars to embrace longer timeframes to capture the complexity of MNEs’ growth and adaptation more meaningfully.Originality/valueBy taking such a long-run perspective, the authors shed new light on the importance of moving beyond simple snapshots to analyse key IB constructs and phenomenon.

Effects of the host-country institutional environment on the operation mode change of international construction enterprises

PurposeThe operation mode of enterprises will affect its resource commitment in the host country, involving different costs and time, as well as risks. Yet, the current state of knowledge about how the institutional environment affects the operation mode change of international construction enterprises is equivocal. This study aims to explore the impact of a host country's institutional environment on the operation mode change of international construction enterprises.Design/methodology/approachFirst, this study proposes a model on the impact of the institutional environment on the operation mode change of international construction enterprises. Second, this study used the Worldwide Governance Indicators (WGI) published by the World Bank and a questionnaire survey to collect data. Finally, the study employs a multiple regression methodology to test the hypothesis and discusses the results.FindingsResults highlight that the important impact of the institutional environment on the operation mode change of international construction enterprises. The results showed that enterprises are more willing to increase resource commitments under the condition of stable institutional environment. In addition, enterprises' market-specific experience and general international experience, as moderating variables, weaken the impact of the institutional environment on the operation mode change. However, general international experience has no significant moderating effect.Practical implicationsThe findings of this study provide practical implications for the investment risk assessment of international construction enterprises. Enterprises need to consider the change in institutional quality and institutional instability of the host country, as well as their own international experience when changing operation mode.Originality/valueThis study extends internationalization theory to the international construction field and provided theoretical guidance for the mechanism of operation mode change of international construction enterprises.

Resilience analysis for tightly coupled constellations of teams

Due to the unrealistic of on-orbit maintenance in space, it is essential to enhance the constellation system&apos;s resilience, i.e., the ability of the system to withstand disruptions and return to a normal state quickly. In this paper, we propose a resilience analysis framework for tightly coupled constellations of teams. The maximum revisit interval is used as the key performance parameter of the system in the resilience measure. We first analyze the probability and the effects of the system&apos;s operation mode change, and then provide a Monte Carlo method for the system resilience quantification. Finally, a tri-satellite constellation of four teams is used as a case to verify the effectiveness of this method.

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Purpose. Increasing the efficiency of the use of pesticides thanks to the substantiation of the parameters of the working bodies and modes of the technological process of layer-by-layer seed treatment, which will ensure an increase in the quality of seed treatment and ecological safety of the environment. Methods. The study used an experimental method using Microsoft Office software environments. Results. The experimental dependences of the height of the seed intensifiers on the angular speed of the rotor and the mass of the seed portion and the dependences of the completeness of seed processing on the mixing time and the mass of the seed portion were obtained. The ranges of changes in rational parameters and modes of operation of working bodies, which ensure the implementation of the technological process of applying protective-stimulating-nutritive preparations to seeds with the required quality of seed processing, is determined. Conclusions. Experimental dependences of the height of the seed intensifiers on the angular speed of the rotor and the mass of the seed portion were obtained and it was established that to ensure the work process of applying preparations to the seeds in the range of angular velocities of the rotor from 15 rad/s to 40 rad/s and the mass of the seed portion from 2.5 kg up to 12.5 kg, the height of the intensifiers should be from 40 mm to 185 mm. Experimental dependences of the completeness of seed treatment on the time of mixing and the weight of the seed portion were obtained and it was established that the completeness of the layer-by-layer treatment of the seeds increases intensively in the first 20 s of mixing, reaching the required value of 80%, and decreases with the increase in the weight of the seed portion. The range of changes in rational parameters and modes of operation of working bodies, which ensure the implementation of the technological process of applying protective-stimulating-nutritive preparations to seeds with the required quality of seed treatment, is determined: the angular speed of the rotor – from 20 rad/s to 40 rad/s, the weight of a portion of seed – from 2.5 kg to 7 kg, supply of working liquid – 4 ml/kg of seeds, temperature of drying agent – up to 100 ºС, supply of drying agent – 0.45 m3/min, mixing time – up to 20 s, drying time – up to 30 s/. Keywords: portion of seeds, seed treater, layer-by-layer processing, protective-stimulating-nutritious preparations.

Justification of the parameters and operating modes of the rotary treated for layer-by-layer processing of seeds

Purpose. Increasing the efficiency of the use of pesticides thanks to the substantiation of the parameters of the working bodies and modes of the technological process of layer-by-layer seed treatment, which will ensure an increase in the quality of seed treatment and ecological safety of the environment. Methods. The study used an experimental method Microsoft Office using software environments. Results. The experimental dependences of the height of the seed intensifiers on the angular speed of the rotor and the mass of the seed portion and the dependences of the completeness of seed processing on the mixing time and the mass of the seed portion were obtained. The ranges of changes in rational parameters and modes of operation of working bodies, which ensure the implementation of the technological process of applying protective- stimulating-nutritive preparations to seeds with the required quality of seed processing, is determined. Conclusions. Experimental dependences of the height of the seed intensifiers on the angular speed of the rotor and the mass of the seed portion were obtained and it was established that to ensure the work process of applying preparations to the seeds in the range of angular velocities of the rotor from 15 rad/s to 40 rad/s and the mass of the seed portion from 2.5 kg up to 12.5 kg, the height of the intensifiers should be from 40 mm to 185 mm. Experimental dependences of the completeness of seed treatment on the time of mixing and the weight of the seed portion were obtained and it was established that the completeness of the layer-by-layer treatment of the seeds increases intensively in the first 20 s of mixing, reaching the required value of 80%, and decreases with the increase in the weight of the seed portion. The range of changes in rational parameters and modes of operation of working bodies, which ensure the implementation of the technological process of applying protective-stimulating-nutritive preparations to seeds with the required quality of seed treatment, is determined: the angular speed of the rotor – from 20 rad/s to 40 rad/s, the weight of a portion of seed – from 2.5 kg to 7 kg, supply of working liquid – 4 ml/kg of seeds, temperature of drying agent – up to 100 ºС, supply of drying agent – 0.45 m /min, mixing time – up to 20 s, drying time – up to 30 s/. Keywords: portion of seeds, seed treater, layer-by-layer processing, protective-stimulating- nutritious preparations.