Mode Of Operation Research Articles

Barriers to Entry in China’s Consumer Goods E-Commerce Market

ABSTRACT Purpose Although economists and strategy theorists have extensively researched market entry barriers in the Western industrial market and post-entry barriers in the e-commerce market, few studies have focused on entry barriers in the context of the unique challenges in China’s business landscape. In this study, a survey was conducted with 139 Chinese marketing executives of consumer goods e-commerce firms to elucidate the dimensions and relative importance of market entry barriers in China. Specifically, this study aims to explore the barriers to entry that exist in the Chinese consumer goods e-commerce market, determine their importance, and identify potential dimensions through factor analysis. Methodology/approach This study employed an in-depth interview with nine marketing executives from China consumer goods e-commerce firms, and the instrument was revised accordingly. Then questionnaire adopted a simple random sampling method to select 300 enterprises as survey respondents. In total, 195 firms completed and returned the questionnaires by the deadline, resulting in 139 valid responses being collected. Findings This study explores 33 entry barriers and reveals seven dimensions of China’s consumer goods e-commerce market, highlighting incumbents with an absolute cost advantage barrier as the most significant barrier, and the cost of establishing a branch office as the least significant barrier, as perceived by Chinese business executives. Research implications Extant literature has mostly confirmed the value and practical significance of market entry barriers in Western markets or industrial markets. However, there are few studies on entry barriers in China’s e-commerce market, particularly in the consumer goods e-commerce market. Our research attempts to provide a theoretical basis for China’s consumer goods e-commerce market entry barriers. Practical implications Studying market entry barriers can help firms better adapt to market changes, optimize their operational modes according to market demands and norms, and enhance their competitiveness. The exploration of this research could be utilized by e-commerce businesses to become more successful or avoid failure. Originality/value/contribution This study complements the existing research on market entry barriers in China and the West. It complements barriers to entry into the consumer e-commerce market based on the Chinese economic context.

ЗБІЛЬШЕННЯ ПРОПУСКНОЇ СПРОМОЖНОСТІ МАГІСТРАЛЬНИХ МЕРЕЖ УКРАЇНИ

In connection with the projected significant increase in electricity demand by 2030, as well as for the purpose of devel-oping the electricity system and effective interaction of the IPS of Ukraine with the energy systems of the European Un-ion, the article considers the need and feasibility of converting the Ukrainian power grids from 330 kV to 400 kV, com-paring the technical characteristics of grids of different voltage classes in terms of reliability, stability and efficiency of such grids. The paper provides an applied analysis of the efficiency of switching 330 kV rated voltage networks to 400 kV voltage class by the criterion of increasing the capacity of electrical equipment and reducing total power losses in the network. On the example of the Dnipro region of the IPS of Ukraine, the complex of computer programs designed for the design of power grids of power systems " Thesaurus" was used to model and analyze the modes of operation of the power grid at 330 kV and 400 kV. As a result, it was found that an increase in the voltage level will lead to a de-crease in the load of certain line sections by 17 %, while the value of total network losses will decrease by 10.8 %. Ref. 4, fig. 3.

Disrupting deliberation? The impact of the pandemic on the social practice of deliberative engagement

The coronavirus pandemic disrupted established ways of doing democracy. This was particularly the case for citizens’ assemblies that have been increasingly commissioned by public authorities to help tackle complex policy problems. The social restrictions adopted in response to the coronavirus pandemic disrupted the ‘deliberative wave’, making the in-person participation of citizens’ assemblies unviable. It forced deliberative practitioners to rethink their standard mode of operation. In this paper, we adopt social practice theory to make sense of how the meanings, competencies and materials associated with the practice of deliberative mini-publics were challenged and, at times, reformulated as practitioners were forced to adapt to digital delivery. Our findings highlight that while aspects of deliberative practice such as inclusivity were rethought, the established identity and competencies of practitioners played a constraining role in the choices and applications of technology.

Innovative protection schemes through hardware-in-the-loop dynamic testing.

In microgrid environments, the behaviour of Distributed Generation (DG) during fault conditions varies significantly based on DG types and penetration levels. Conventional Overcurrent Relays (OCRs) with standard time-current characteristics may exhibit limitations during excessive fault scenarios, leading to OCR operating delays and mis-coordination within the microgrid. This study proposes a novel constraint on the maximum Current Multiplier Setting (CMS) and utilizes Water Cycle Algorithm (WCA) and Particle Swarm Optimization (PSO) techniques to optimize the Time Multiplier Setting (TMS). Comparative dynamic analysis through real-time validation shows that the non-standard OCR approach outperforms the standard IEC scheme across all grid operation modes with different type, size and location of DGs. For instance, under F1 conditions, the tripping time of OCR1 was reduced from 0.0226 seconds (IEC) to 0.000981 seconds (non-standard). HIL results further affirm the efficacy of the proposed scheme. The optimization process, implemented in MATLAB and validated using ATP/EMTP simulations and SIPROTEC 7SJ62 relays, demonstrates enhanced microgrid protection coordination, improving system reliability and performance.

Design and development of the machine protection system for HIAF

ABSTRACT The High Intensity Heavy-ion Accelerator Facility (HIAF), currently under construction, is a complex machine that couples a Continuous Wave (CW) superconducting ion Linear accelerator (iLinac) with a high-energy synchrotron to produce various stable and radioactive intense beams with energies from MeV/u to GeV/u. The machine has a versatile operation mode which requires a high flexibility and reliability to the Machine Protection System (MPS). A customized and robust MPS is designed and developed to give the readiness of the machine for operation, to mitigate and analyze faults related to the relative damage potential. To get a high speed and have a high level of reliability, all interlock signal processing is processed on radiation-tolerant Field-Programmable Gate Arrays (FPGA) with triple or dual redundancy, as well as with a fail-safe design. By implementing a multiprocessing platform system-on-chip FPGA, the HIAF MPS can be tightly integrated with other systems to maximize availability pinpoint failures for operations, and give the postmortem analysis. This paper will describe the architecture of the interlocks linking the protection systems, the strategies to manage the complexity, the detailed components, and the interlock logic of the customized HIAF MPS, as well as the test and verification of the prototype.

HYDROSAFE: A Hybrid Deterministic-Probabilistic Model for Synthetic Appliance Profiles Generation.

Realistic appliance power consumption data are essential for developing smart home energy management systems and the foundational algorithms that analyze such data. However, publicly available datasets are scarce and time-consuming to collect. To address this, we propose HYDROSAFE, a hybrid deterministic-probabilistic model designed to generate synthetic appliance power consumption profiles. HYDROSAFE employs the Median Difference Test (MDT) for profile characterization and the Density and Dynamic Time Warping based Spatial Clustering for appliance operation modes (DDTWSC) algorithm to cluster appliance usage according to the corresponding Appliance Operation Modes (AOMs). By integrating stochastic methods, such as white noise, switch-on surge, ripples, and edge position components, the model adds variability and realism to the generated profiles. Evaluation using a normalized DTW-distance matrix shows that HYDROSAFE achieves high fidelity, with an average DTW distance of ten samples at a 1Hz sampling frequency, demonstrating its effectiveness in producing synthetic datasets that closely mimic real-world data.

Performance of a Methanol-Fueled Direct-Injection Compression-Ignition Heavy-Duty Engine under Low-Temperature Combustion Conditions

Low-temperature combustion (LTC) concepts, such as homogeneous charge compression ignition (HCCI) and partially premixed combustion (PPC), aim to reduce in-cylinder temperatures in internal combustion engines, thereby lowering emissions of nitrogen oxides (NOx) and soot. These LTC concepts are particularly attractive for decarbonizing conventional diesel engines using renewable fuels such as methanol. This paper uses numerical simulations and a finite-rate chemistry model to investigate the combustion and emission processes in LTC engines operating with pure methanol. The aim is to gain a deeper understanding of the physical and chemical processes in the engine and to identify optimal engine operation in terms of efficiency and emissions. The simulations replicated the experimentally observed trends for CO, unburned hydrocarbons (UHCs), and NOx emissions, the required intake temperature to achieve consistent combustion phasing at different injection timings, and the distinctively different combustion heat release processes at various injection timings. It was found that the HCCI mode of engine operation required a higher intake temperature than PPC operation due to methanol’s low ignition temperature in fuel-richer mixtures. In the HCCI mode, the engine exhibited ultra-low NOx emissions but higher emissions of UHC and CO, along with lower combustion efficiency compared to the PPC mode. This was attributed to poor combustion efficiency in the near-wall regions and engine crevices. Low emissions and high combustion efficiency are achievable in PPC modes with a start of injection around a crank angle of 30° before the top dead center. The fundamental mechanism behind the engine performance is analyzed.

Distributed photovoltaic supportability consumption method considering energy storage configuration mode and random events

In order to improve the control capability of distributed photovoltaic support, a distributed photovoltaic support consumption method based on energy storage configuration mode and random events is proposed. A networked and constrained parameter analysis model for distributed photovoltaic power supply control was constructed. Based on the direct flexible mode of optical storage, an AC/DC voltage level control model for distributed solar power supply control was constructed. In the operation mode of DC hybrid distribution network, the demand response tracking identification method was used to analyze the uncertain characteristic parameters of distributed solar power supply load, and combined with the planned energy storage capacity parameters, the distributed solar power supply load and photovoltaic output were estimated. By configuring the optimal energy storage capacity, adjusting the power distribution of the microgrid, and integrating the analysis of uncertain factors and random events in the energy storage configuration mode, the design of distributed photovoltaic support consumption has been achieved. The experimental results show that the distributed photovoltaic absorption control using this method has lower load requirements, can effectively reduce the exchange power of the interconnection line, and improve the configuration scale, system reliability, and economy of the photovoltaic energy storage system.

Synchronous PIV measurements of a self-powered blood turbine and pump couple for right ventricle support

A blood turbine-pump system (iATVA), resembling a turbocharger was proposed as a mechanical right-heart assist device without external drive power. In this study, the iATVA system is investigated with particular emphasis on the blood turbine flow dynamics. A time-resolved 2D particle image velocimetry (PIV) set-up equipped with a beam splitter and two high speed cameras, allowed simultaneous recordings from both the turbine and pump impellers at 7 different phased-locked instances. The iATVA prototype is 3D printed using an optically clear resin following our earlier PIV protocols. Results showed that magnetically coupled impellers operated synchronously. As the turbine flow rate increased from 1.6 to 2.4 LPM, the rotational speed and relative inlet flow angle increase from 630 to 900 rpm, and 38 to 55% respectively. At the trailing edges, backflow region spanned 3/5 of the total passage outlet flow, and an extra leakage flow was observed at the leading edge. For this early turbine design, approximately, 75% of the turbine blade passage was not contributing to the impulse operation mode. The maximum non-wall shear rate was ~ 2288 s−1 near to the inlet exit, which is significantly lower than the commercial blood pumps, encouraging further research and blood experiments of this novel concept. Experimental results will improve the hydrodynamic design of the turbine impeller and volute regions and will be useful in computational fluid dynamics validation studies of similar passive devices.

Research on the Development of Agricultural Products Logistics under the Value Chain Optimization Concept of Logistics Management

The value chain of logistics management is the key to meeting the needs of circulation entities, improving logistics efficiency, optimizing logistics division of labor, and promoting the upgrading of logistics enterprises. It plays a positive role in promoting the development of agricultural product logistics. However, it is understood that there are still many problems in China's agricultural product logistics system, such as opaque information, multiple circulation links, high costs, high losses, and low profits. These will reduce the optimization of logistics management value chain, leading to low efficiency in agricultural product circulation and entering a low consumption cycle mode. Therefore, based on the concept of optimizing the value of logistics management, this article analyzes the development difficulties of the current agricultural product reverse logistics model, explores the design and operation mode of the agricultural product reverse logistics system, proposes corresponding countermeasures to maximize the value chain of agricultural product logistics management, in order to promote the stable and sustainable development of agricultural product logistics and improve the circulation efficiency of agricultural products.

Optimal operation of solid-oxide electrolysis cells considering long-term chemical degradation

Optimizing the performance of solid oxide electrolysis cells (SOECs) for long-term hydrogen (H2) production at high temperatures is crucial, as prolonged operation leads to efficiency losses and shorter cell lifespans due to chemical degradation. In this work, we adopt a quasi-steady state approach for dynamic optimization over extended operational periods to address the disparity in timescales between cell operation and degradation. Integrating a 2-D non-isothermal SOEC model with balance-of-plant (BOP) equipment, we explore three optimization objectives: minimizing terminal degradation, maximizing integral efficiency, and minimizing the levelized cost of H2 (LCOH). Our dynamic optimization algorithm reduces LCOH by 9.5% and 16% compared to strategies focusing solely on terminal degradation and integral efficiency, respectively. For electricity prices of 0.03 $/kWh and 0.3 $/kWh, optimal replacement schedules range from 5 to 2 years, depending on the operational mode. Furthermore, a flexible operational mode yields additional improvements in LCOH over traditional galvanostatic and potentiostatic modes.

Development of a Device for Primary Purification of Mung Bean Grain from Pods and Optimization of Its Main Design Dimensions and Operating Modes

Development of a Device for Primary Purification of Mung Bean Grain from Pods and Optimization of Its Main Design Dimensions and Operating Modes

Numerical study on heat restoration cycle performance of energy pile with backfilling PCM

The numerical analysis of energy pile backfilled with phase change material (PCM) was performed for the renewable geothermal energy utilization in building energy savings. Different operation modes and the melting temperature, latent heat, thermal conductivity of the PCMs within the energy piles were discussed to obtain the optimal parameters. Further, the restoration and heat transfer performance of energy piles were also analyzed for the prolonged operation. It was concluded that relatively higher latent heat and thermal conductivity were preferable to enhance the heat transfer rate per meter (Qm) of the PCM-backfilled energy pile. However, a relatively lower PCM latent heat may help to full utilization and restoration of PCMs during every cycle of cooling and heating when energy pile works. An ideal melting temperature of PCM is probably close to the initial soil temperature to achieve preferred restoration and heat transfer performance, rather than the inlet fluid temperature. In heating 12 h and cooling 12 h alternate mode, taking continuous operation as a reference, the Qm and the restoration rate of pile wall temperature of the PCM-backfilled energy pile were increased by 32.7 % and 52.5 % after operating 720 h.

How to choose mobile energy storage or fixed energy storage in high proportion renewable energy scenarios: Evidence in China

With the large-scale integration of renewable energy and changes in load characteristics, the power system is facing challenges of volatility and instability. Therefore, enhancing the safe and stable operation capability of the power system is an urgent problem that needs to be solved. Mobile energy storage can improve system flexibility, stability, and regional connectivity, and has the potential to serve as a supplement or even substitute for fixed energy storage in the future. However, there are few studies that comprehensively evaluate the operational performance and economy of fixed and mobile energy storage systems. To comprehensively evaluate the economic benefits of large-scale mobile energy storage systems, this paper constructs an overall horizontal cost model for energy storage systems that considers the power system and train transportation system. This model not only introduces the traditional concept of lifecycle cost of energy storage systems, but also considers the costs of traditional transmission lines and battery transportation. Secondly, to achieve simulation of large-scale mobile energy storage system planning and operation, this paper establishes a multi-region power planning and operation simulation (MPO) model and a battery transportation and logistics (BTL) model to accurately reflect the operation mode of fixed energy storage and mobile energy storage in the power system. Finally, taking the actual power grids and railway networks in Northeast and North China as case studies, this article provides an in-depth analysis of the technical, economic, and environmental performance of large fixed and mobile energy storage systems, and conducts a detailed comparison. The research results indicate that under high grid connection ratios (using 75% and 66% as examples), the overall cost of mobile energy storage systems continues to decrease to 1.42 CNY/kWh and 0.98 CNY/kWh. Compared to fixed energy storage at 5.45 CNY/kWh and 4.79 CNY/kWh, it has an absolute economic advantage and shows significant carbon reduction capabilities, reaching 241,800 to 1,394,600 tons. This discovery fully confirms the enormous potential and application value of mobile energy storage in high proportion renewable energy scenarios, providing strong technical support and economic analysis basis for the sustainable development of the power system.

Kinetic analysis of an optically pumped rare gas lasing medium with a nanosecond repetitively pulsed discharge in Ar-He mixture

A kinetic model of a lasing medium for an optically pumped rare gas laser (OPRGL) was developed that accounts for the production of excited argon atoms Ar* in a nanosecond repetitively pulsed discharge (NRPD). Analytical formulas were derived for the frequency of Ar* radiation losses, population of the energy levels involved in the laser cycle and specific powers for pump absorption and lasing in the limit of bleaching of pump and lasing transitions. The formulas use the kinetic constants of the model as parameters and Ar* number density as the independent variable. Periodic solutions for number density of plasma components, pump absorption and small signal gain, specific pump absorption and lasing were obtained numerically. Mean over the NRPD period values of Ar* number density, specific pump absorption and lasing were calculated as the functions of the preset peak values of the reduced electric field E/N. Triangular electric field pulses of 80 ns FWHM duration and 200 kHz frequency were considered. Optical pumping increases Ar* loss by more than a factor of 10, due to excess spontaneous emission from Ar* levels that populates the 1s4 state of argon, resulting in a reduced NRPD plasma ionization and Ar* production. As a result, without auxiliary optical pumping from the 1s4 state that compensates this loss, the averaged across the discharge period Ar* number density decreases by a factor of 30. Moreover, the average specific heat release in plasma becomes almost equal to the specific lasing power in the acceptable operating modes, making auxiliary optical pumping mandatory for scaling of an OPRGL. The sensitivity of the results to the values of kinetic constants in the model is analyzed.

Methane biohydroxylation into methanol by Methylosinus trichosporium OB3b: possible limitations and formate use during reaction.

Methane (CH4) hydroxylation into methanol (MeOH) by methanotrophic bacteria is an attractive and sustainable approach to producing MeOH. The model strain Methylosinus trichosporium OB3b has been reported to be an efficient hydroxylating biocatalyst. Previous works have shown that regardless of the bioreactor design or operation mode, MeOH concentration reaches a threshold after a few hours, but there are no investigations into the reasons behind this phenomenon. The present work entails monitoring both MeOH and formate concentrations during CH4 hydroxylation, where neither a gaseous substrate nor nutrient shortage was evidenced. Under the assayed reaction conditions, bacterial stress was shown to occur, but methanol was not responsible for this. Formate addition was necessary to start MeOH production. Nuclear magnetic resonance analyses with 13C-formate proved that the formate was instrumental in regenerating NADH; formate was exhausted during the reaction, but increased quantities of formate were unable to prevent MeOH production stop. The formate mass balance showed that the formate-to-methanol yield was around 50%, suggesting a cell regulation phenomenon. Hence, this study presents the possible physiological causes that need to be investigated further. Finally, to the best of our knowledge, this study shows that the reaction can be achieved in the native bacterial culture (i.e., culture medium containing added methanol dehydrogenase inhibitors) by avoiding the centrifugation steps while limiting the hands-on time and water consumption.

Thermodynamic performances of a power-to-X system based on solar concentrating photovoltaic/thermal hydrogen production

100% renewable power-to-X (fuel, power, and heat products) systems have great application potential for the achievement goal of carbon neutrality. However, the extensive chain of the power-to-X system could result in low energy utilization efficiency. A novel composite-parabolic-concentrating photovoltaic/thermal-collector-based power-to-X system utilizing 100% solar energy is proposed, which integrates proton exchange membrane electrolysis cells and proton exchange membrane fuel cells to provide heat, electricity, and hydrogen. Thermodynamic models for each subsystem are established, and energy and exergy efficiencies are assessed in the thermodynamic laws. Three operation modes are analyzed to adapt to the variations of solar radiation and a residential building is used as an application scenario to evaluate its thermodynamic and economic performances in dynamic variations of solar radiations and energy demands. The effects of key operating parameters, such as solar radiation intensity, photovoltaic coverage ratio, current density, and operating temperature, on the performances are investigated. The maximum exergy destruction of the concentrator photovoltaic/thermal collector is 93.20% at the rated operating conditions, and the system exergy and energy efficiencies are 9.11% and 48.97%, respectively. The economic results demonstrate that the levelized costs of solar power, hydrogen, and fuel cell power are 0.2936 $/kWh, 21.70 $/kg, and 2.1520 $/kWh, respectively.

Optimization Analysis of Comprehensive Budget Management from the Perspective of Digital Restructuring: Taking a Water Company as an Example

This article takes water enterprises as the research object, exploring the organic combination of comprehensive budget management under the trend of digitalization and digital technology in the new era, as well as the process of management system reform. Introduce the current status of its budget management work, comprehensively analyze the architecture and operation mode of the current comprehensive budget management system of water enterprises, and evaluate and analyze the overall situation and shortcomings of its budget management system based on financial data such as budget formulation and execution. From the perspective of digital restructuring and upgrading of comprehensive budget management work, corresponding countermeasures are proposed to make up for the shortcomings and suggestions for the future development of the enterprise’s comprehensive budget.

Analytical investigation of interleaved input/output parallel DAB converter for grid scale battery storage

With the surge of integration of intermittent renewable energy sources into the grid the installation of large scale battery energy storage is rising at a rapid rate to support the power system. The grid scale battery storage needs to be scalable with varying power system requirements. Parallel connected modular dual active bridge (DAB) converter with high frequency transformers interface can facilitate adjustable large power flow for grid scale battery storage. The high gain between LV and HV side can be achieved using isolated high frequency transformers and parallelism of the DAB converter with efficient and smooth bidirectional power transfer capability. In this paper, a generalized interleaving operation (ILO) on both input and output parallel connected DAB (IOPDAB) converter has been proposed for large energy storage capability and to enable improved quality of power flow. The generalized expressions of peak currents, average circulating current and active power flow, has been developed for the IOPDAB converter with n-parallel connected DAB modules. A detailed analytical investigation has been carried out to show the improved currents profile in both input and output sides in the interleaved mode. The operating performance of the IOPDAB converter has been shown using PSCAD/EMTDC software based simulation. The results are verified through laboratory experimental setup with two interleaved I/O parallel DAB using Spartan 3AN FPGA processor as controller. A performance comparison has been done with the non-interleaving operation (NILO) and interleaving operation (ILO) modes, and it is shown that the ILO mode has better performance in terms of efficiency, Input/output ripple current reduction, increased ripple frequency and circulating current minimization.

A hierarchical energy management strategy for DC microgrid hybrid energy storage systems based on fractional-order sliding mode controller

A hierarchical energy management strategy (EMS) for a fuel cell (FC)-supercapacitor (SC)‑lithium battery hybrid energy storage system (HESS), based on a fractional-order sliding mode controller (FOSMC), is proposed to address the nonlinear behavior of low-voltage direct current (DC) microgrid HESS. To fully exploit the energy of the SC, the system management layer divides the EMS into maximum power operation mode and state machine control algorithm operation mode. For the first time in equipment control layer, a FOSMC, more suitable for handling nonlinear characteristics, is employed, and its stability is evaluated using the Lyapunov method. Finally, a 48 V HESS experimental platform is constructed for validation, demonstrating that the proposed EMS enhances the stability, response speed, and robustness of the HESS. Compared to conventional sliding mode controller (SMC) and integral sliding mode controller (ISMC), the adoption of a FOSMC reduces the steady-state error of the bus voltage by at least 9.1 % and increases the response speed by at least 11.1 %, while exhibiting good robustness to external disturbances and uncertainties in controller parameters. This fills the current research gap in parameter robustness validation.