Long-term Power Research Articles

The case study of a Luxury Street-wear Fashion Brand Off-White

Fashion has always been a controversial topic. In recent years, there has been an increasing number of fashion brands, but it seems that Off-White stands out as the leader in the whole luxury fashion industry. So this research paper not only qualitatively summarizes the reasons the famous luxury streetwear fashion brand, Off-White rapidly gained such popularity these years, but also reveals what makes Off-White blow out. This case study utilizes a SWOT structure throughout the article, which can be basically categorized into five different sections: the strengths, weaknesses, opportunities, threats, and potential survival plans or expansion for the future. It is noticeable that one of Off-White’s biggest strengths is that it has built a long-term collaborative power with varied competitors and several celebrity endorsements. As a result, it only takes Off-White approximately five years to become the most prestigious luxury streetwear fashion brand all over the globe. While it is true that Off-White has faced much more difficulties, especially after the sudden death of its designer Virgil Abloh; living in such an era of digital media, in order to survive or broaden its reputation in the future, all they need to do is to seize this opportunity and utilize lawsuits to defend its legalized equities and keep collaborative partnerships with those rivals and superstars.

How Fast to Avoid Carbon Emissions: A Holistic View on the RES, Storage and Non-RES Replacement in Romania

The European Union targets aim to replace the non-renewable energy sources (non-RES) of coal, oil and gas (COG) generation with RES and storage (RES-S). The replacement of COG-generating units will lead to a decrease in CO2 emissions and a better living environment. Starting from this desideratum, in this paper, we create several scenarios to replace COG in Romania with RES-S, reconsider future energy mixes and engage with a more creative planning in order to meet the clean energy transition path. The energy shortages, especially in European countries after the Russian invasion of Ukraine, led many governments (including the Romanian, Polish, etc.) to think more about short-term supply issues and less about medium- and long-term power system planning. However, the decision makers of the European power systems have to decide how fast to avoid firing coal, how fast to adopt RES and how fast to invest in flexibility sources, including storage stations to enable a higher integration of RES. Therefore, in this paper, a holistic view to envision the RES and non-RES contribution to the load coverage in Romania for a smooth transition to a low-carbon economy is provided. The results show that an initial mix of wind, photovoltaic (PV) and storage systems is preferable to substitute 600 MW of installed power in coal-based power plants. Furthermore, the case of Poland-the European country with over 70% coal in its generation portfolio-is also presented as it can serve as a good example.

ACCIDENT LESSONS AT THE FUKUSHIMA-DAIICHI NPP FOR THE SAFETY OF THE NUCLEAR POWER INDUSTRY IN UKRAINE

The main causes of destructive steam and gas explosions with catastrophic environmental consequences during the accidents at Fukushima-Daiichi NPP were the loss of tightness of the passive safety systems of the reactor residual fuel removal safety system and the critical residual heat removal function in the spent nuclear fuel holding tank . The main lesson of the Fukushima accident for the environmental safety of Ukraine's nuclear power industry is the need to anticipate the possibility of unlikely emergency events with catastrophic environmental consequences. Such unlikely events include: flooding of the nuclear power plant site, complete long-term blackout, steam-gas destructive explosions, joint action of external extreme phenomena. Based on this, the following lessons of the Fukushima accident were formulated for the nuclear power industry of Ukraine regarding unlikely emergency events with catastrophic environmental consequences: lesson 1 - the need for reliable isolation of diesel generator rooms from external extreme events; lesson 2 - the need to improve strategies and methods of managing accidents with complete long-term blackout and lesson 3 - the need to determine the conditions of steam-gas explosions. The lessons of the Fukushima accident and the known results of the analysis of explosive conditions in nuclear power plants with WWER determine the need to improve methods for modeling the conditions and consequences of steam and gas explosions at the dynamic stages of emergency processes.The lessons of the Fukushima accident and the results of the calculated modeling of accidents with complete long-term power outages of nuclear power plants with WWER determine the need to improve strategies and ways to prevent and manage accidents with complete long-term power outages.A promising approach is the integrated use of additional passive safety systems to ensure the function of feeding steam generators with turbopumps (area for high pressures) and natural circulation (area for low pressures).

Efficient Distributed Wireless Power Transfer System for Multiple Wearable Sensors through Textile Coil Array

When it is necessary to detect various physiological signals of the human body, clothing embroidered with near-field effect patterns can be used as a long-term power supply medium to supply power to long-distance transmitters and receivers to form a wireless power supply system. The proposed system uses an optimized parallel circuit to achieve a power transfer efficiency of more than five times higher than that of the existing series circuit. The power transfer efficiency of simultaneously supplying energy to multiple sensors is increased higher than five times and even more when only one sensor is coupled. When powering eight sensors at the same time, the power transmission efficiency can reach 25.1%. Even when eight sensors powered by the coupled textile coils are reduced to one, the power transfer efficiency of the whole system can reach 13.21%. Additionally, the proposed system is also applicable when the number of sensors ranges from 2 to 12.

Optimal Design Towards High Performance of Sandwich Flexible Piezoelectric Energy Harvesters

AbstractThe flexible piezoelectric energy harvester (FPEH), as an effective strategy for long-term power supply of implantable and wearable electronics, requires high areal output energy density, low mechanical stiffness, and high energy efficiency, simultaneously. The widely adopted sandwich FPEH, consisting of one relatively hard substrate sandwiched between two piezoelectric films, can provide a high areal output energy density, but also high mechanical stiffness and low energy efficiency due to its energy-wasting deformation of the hard substrate. Here, we propose a novel optimal soft-substrate sandwich FPEH with designs of sufficient length and optimized Young’s modulus of the substrate, which is much smaller than that of the piezoelectric film. A sandwich beam model considering both the bending and shearing of the soft substrate and the one-way coupling of the piezoelectric effect was adopted for the theoretical analysis and optimal design. The optimal soft-substrate sandwich FPEH exhibits greatly improved overall performance with a 33% increase in areal output energy density, a 51% reduction in mechanical stiffness, and a 177% increase in energy efficiency, simultaneously. Systematic theoretical analysis is performed to illustrate the mechanism and guide the optimal design. The novel optimal soft-substrate sandwich FPEH is then applied to harvesting energy from various living subjects. This optimal design can be extended to other types of mechanical energy harvesters with a similar laminated structure.

Load Forecasting Research of Markov Chain based on Data Modeling

The introduction of the electricity market plays an irreplaceable role in assisting the power industry to achieve stable operation and planning of the power grid, promoting the effective use and dispatch of electric energy, and avoiding the waste of resources. The role of load forecasting for the electricity market is self-evident, in the context of big data, by building a load forecasting model based on the Markov chain, and using the actual data of a certain region for simulation calculation. The results show that the Markov forecasting method can play a good role in medium and long-term power load forecasting, and can be used as a supplement to conventional load forecasting.

Cross-Layer Resource Allocation in HetNet NOMA Systems With Dynamic Traffic Arrivals

Non-orthogonal multiple access (NOMA) has become a promising candidate aiming to enhance the system performance in the fifth generation of wireless communication. However, most existing studies on the resource allocation of NOMA systems only consider the short-term performance improvement but ignore the problems caused by the imperfect time-varying channels and the dynamic traffic arrivals, which will result in unsuccessful transmission issues. Different from the existing approaches, we propose a long-term cross-layer resource allocation model with dynamic traffic arrivals and limited channel information. With the low-overhead one-bit feedback, the optimal decoding order, user scheduling, and power allocation are analyzed. Specifically, the problem is formulated as a stochastic optimization framework to minimize long-term power consumption. By applying the Lyapunov optimization framework, the problem can be transformed into a joint traffic rate control and mixed-integer programming resource allocation problem. This NP-hard problem is difficult to be solved directly. Therefore, we devise an efficient sub-optimal algorithm with the dynamic penalty factor. In our theoretical analysis, we prove that the delay-power tradeoff can be achieved by tuning a control parameter. The simulation results confirm that our proposed algorithms can efficiently reduce the power consumption compared with the baseline algorithms while satisfying the QoS requirements.

Individual cultural values as determinants of the attitudinal process in the restaurant: a different perspective for understanding brand equity formation

In an increasingly innovative competitive environment, it is necessary to know the customer in depth and to understand the intrinsic determinants of customer loyalty to the restaurant and brand equity. Culture is a fundamental factor in understanding behaviour, which has often attracted interest because of its moderating rather than determining role. The objective of this research is to examine the determinant role of customers' cultural values (long-term orientation, power distance, and uncertainty avoidance) on the customer's attitudinal process in the restaurant (satisfaction and loyalty) in order to understand how it indirectly affects through the attitudinal process the formation of a restaurant's brand equity. A sample of 540 customers was used, and a SEM model was estimated. The results indicate that cultural values, except for power distance, strongly determine the attitudinal process. Therefore, culture indirectly affects the formation of the restaurant's brand equity.

The impact of carbon emission reduction inputs of power generation enterprises on the cost of equity capital.

This paper aims to encourage power generation enterprises to actively carry out emission reduction activities by studying the impact of carbon emission reduction investment on long-term development. The existing literature mainly studies the interaction between national economic development and energy consumption at the macro level, and the impact of environmental protection investment by enterprises at the micro level on the short- and long-term economic consequences. However, there is still a large space for research on how specific emission reduction measures lead the long-term development of enterprises. Therefore, this paper chooses to introduce enterprise competitiveness, government subsidy, and management shareholding ratio respectively to conduct intermediary test and grouping regression, and empirically studies the mechanism of carbon emission reduction input of Chinese power generation enterprises on the cost of equity capital from 2013 to 2020. The results show that management shareholding can enhance the initiative of enterprises to reduce emissions. At the same time, carbon emission reduction investment can effectively reduce the cost of equity capital by improving the competitiveness of enterprises and forming a reputation mechanism faster. This study reveals the significance of carbon emission reduction investment as an important part of enterprise environmental protection investment, and emphasizes that the government and enterprises can effectively avoid the short-sighted tendency of enterprises and improve the long-term development power of enterprises by adjusting government subsidies, management shareholding ratio and other policies.

Optimizing Hybrid Power for Manpura Island: A Case Study in Bangladesh

In the remote and isolated island Manpura in southern Bangladesh, located within the Bhola district and surrounded by the Meghna River, most communities rely on farming and fishing for their livelihoods. Due to its isolation, the island is not connected to the mainland's electrical grid. In this study, a freestanding green hybrid energy system was proposed for the Manpura island using HOMER software to meet the electricity needs of its 17,016 households. The average load for the system is 9,149.87 kWh per day, with an annual peak load of 2,112.6 kW. The system would utilize PV panels, hydrokinetic energy, biogas, wind turbines, storage, and a converter, with a total Net Present Cost (NPC) of 23,796,260.00 and a Cost of Energy (COE) of $0.5515. This hybrid energy systems would provide a sustainable and cost-effective long-term power solution for the island while preserving its natural beauty.

A Hybrid Piezoelectric and Electromagnetic Broadband Harvester with Double Cantilever Beams

Vibration-energy harvesting is an effective strategy for replacing batteries and provides a long-term power supply to microelectronic devices. Harvesting vibration energy from human motions has attracted research attention in recent years. Here, a novel low-frequency hybrid piezoelectric and electromagnetic broadband harvester is proposed. Two parallel piezoelectric cantilever beams support the harvester and capture environmental vibration energy based on the piezoelectric effect. A permanent magnet is connected by springs to the two beams, and a fixed coil surrounds the moving permanent magnet, enabling energy conversion via the electromagnetic effect and the proof mass. The parameters influencing the output power of the harvester are optimized numerically to boost the harvester's performance. The output power of the proposed hybrid harvester is compared with that of a piezoelectric harvester and an electromagnetic harvester. The simulation results show that the output power is significantly higher for the hybrid harvester than for the piezoelectric and electromagnetic harvesters, and the bandwidth is broader owing to the double cantilevers. An experiment is conducted using a prototype of the hybrid harvester to evaluate its output power. The results show multiple resonant peaks, an extended bandwidth, and a maximum power of 6.28 mW. In contrast, the maximum harvested power of the piezoelectric harvester is only 5.15 mW at 9.6 Hz.

Spotlight on the spot market: A review of the indian wholesale electricity market

The Indian Power Exchanges that started in 2008 have remained highly illiquid with less than 10 % liquidity in the day ahead market and short-term contracts after 14 years of operation. The dominance of long-term (25 year) Power Purchase Agreements (PPA) with coal power plants have stifled the wholesale spot market development and may jeopardize the successful integration of 450 GW renewables being targeted for 2030. The coal PPAs are inflexible with a significant take-or-pay provisions and are also more expensive than renewable generation in many cases. Although there has been a recent effort to bring in renewables in the spot market, it took the form of a separate “green” day ahead market rendering the market fragmented. The focus needs to be brought back to a layered integrated spot market which needs to be the fulcrum of all trade be it renewables, cross border trade and eventually frequency control ancillary services products. While contracts are an essential part of any market, their volume, tenure and prices, however, must be informed by spot prices. If India needs to achieve its 450 GW RE target (by 2030), there must be a reform of the thermal PPA regime to bring this generation into the day ahead and real-time spot markets to form a liquid and efficient marketplace.

Advances in high-voltage supercapacitors for energy storage systems: materials and electrolyte tailoring to implementation.

To achieve a zero-carbon-emission society, it is essential to increase the use of clean and renewable energy. Yet, renewable energy resources present constraints in terms of geographical locations and limited time intervals for energy generation. Therefore, there is a surging demand for developing high-performance energy storage systems (ESSs) to effectively store the energy during the peak time and use the energy during the trough period. To this end, supercapacitors hold great promise as short-term ESSs for rapid power recovery or frequency regulation to improve the quality and reliability of power supply. In particular, the electrical double layer capacitor (EDLC) which offers long and stable cycle retention, high power densities, and fast charge/discharge characteristics with a moderate operating voltage window, is a suitable candidate. Yet, for implementation of the EDLC in ESSs, further research effort is required in terms of increasing the operating voltage and energy densities while maintaining the long-term cycle stability and power densities which are desirable aspects for ESS operation. Here, we examine the advances in EDLC research to achieve a high operating voltage window along with high energy densities, covering from materials and electrolytes to long-term device perspectives for next-generation supercapacitor-based ESSs.

Control strategy of DFIG and SVG cooperating to regulate grid voltage of wind power integration point

To better solve doubly-fed wind farms' voltage stability control problem with static var generator (SVG), this paper proposes and designs a reactive power regulation strategy based on SVG and doubly-fed wind turbines. To stabilize the voltage of the wind farm, SVG is preferred for reactive power compensation when the voltage fluctuates. After the voltage is stable, the reactive power output of SVG and the doubly-fed induction generator (DFIG) is adjusted according to the system state. The DFIG can output enough reactive power and meet the specified power factor conditions. The control mode adopts a real-time tracking mode to monitor the voltage of the control bus. In the model, comprehensive optimization indexes consider the maximum voltage offset, the time-consuming voltage to enter the stable range, the steady-state voltage deviation, and the average voltage offset in voltage fluctuation. The genetic algorithm optimizes the proportional-integral (PI) controller parameters of DFIG and SVG reactive reference values. DFIG and SVG have better response effects to voltage fluctuation than before optimization. Finally, the grid model of DFIG is built, and the simulation results verify the effectiveness and correctness of the proposed method. The cooperative control strategy of SVG and DFIG can adjust the voltage quickly and avoid the long-term reactive power flow between them.

Wave-to-wire modelling of a vibro-impact wave energy converter for ocean data buoys

In this study, a wave-to-wire (W2W) model of a vibro-impact wave energy converter (VIWEC) is proposed for powering ocean data buoys. A battery and a supercapacitor are integrated to the VIWEC to form a hybrid energy storage system (HESS), in order to provide continuous and long-term DC power for the payloads of ocean data buoys. Based on the W2W model, controllers for maximising wave energy capture and managing the HESS are integrated, and then implemented by fully controllable AC/DC and DC/DC converters. On the basis of irregular waves, preliminary results show that the proposed W2W model with control can provide stable and continuous DC power. Thus, the proposed W2W model, integrated with HESS and control, can be used to investigate its feasibility and to assess its performance for ocean data buoys.

Medium- and long-term power load forecasting model

Power load is an important part of power system, and power load forecasting has an important impact on power system analysis, design and control. With the development of smart micro grid, load forecasting has gradually become an important module in the energy management system, It is “source, network, load and storage” “An important link in energy flow matching. The staged combined demand forecasting model of power grid based on neural network and polynomial regression is adopted, and judgment conditions are added to the neural network. If the training sample data does not converge in the neural network training process, the neural network forecasting is terminated, and the data is automatically transferred to the polynomial regression model to obtain the forecasting results. This method can be initially used for annual and monthly load forecasting. It is an intelligent micro grid The planning of has laid a certain technical foundation.

Development of an agent model to investigate the impact of wholesale power trading on the long-term power source selection

Development of an agent model to investigate the impact of wholesale power trading on the long-term power source selection

Joint Decision-Making Model of Power Manufacturer Participation in Green Certificate Market and Medium - and Long-Term Power Market

To effectively guide power manufacturers in the medium and long-term market and green certificate market trading behavior. This paper firstly constructs the model of power manufacturers' participation in the green certificate market and the model of participating in the medium and long-term market of power, and establishes the coupling constraint of power manufacturers' participation in the power market and the green certificate market. Secondly, considering the speculative behavior of power manufacturers and using conditional value-at-risk to depict the profit risk of electricity generation due to the uncertainty of market price, the optimal comprehensive benefit considering the annual expected profit and risk of power manufacturers is taken as the decision-making objective, and the joint decision-making model of power manufacturers participating in the green certificate market and the medium and long term power market is established. It is helpful for power manufacturers to make trading decisions in medium and longterm market and green certificate market.

Thulium-doped all-PM fiber chirped pulse amplifier delivering 314 W average power

Abstract A high-power all polarization-maintaining (PM) chirped pulse amplification (CPA) system operating in the 2.0 μm range is experimentally demonstrated. Large mode area (LMA) thulium-doped fiber (TDF) with a core/cladding diameter of 25/400 μm is employed to construct the main amplifier. Through dedicated coiling and cooling of the LMA-TDF to manage the loss of the higher order mode and thermal effect, a maximum average power of 314 W with a slope efficiency of 52% and polarization extinction ratio of 20 dB is realized. The pulse duration is compressed to 283 fs with a grating pair, corresponding to a calculated peak power of 10.8 MW, considering the compression efficiency of 88% and the estimated Strehl ratio of 89%. Moreover, through characterizing the noise properties of the laser, an integrated relative intensity noise of 0.11% at 100 Hz−1 MHz is obtained at the maximum output power, whereas the laser timing jitter is degraded by the final amplifier from 318 to 410 fs at an integration frequency of 5 kHz to 1 MHz, owing to the self-phase modulation effect-induced spectrum broadening. The root-mean-square of long-term power fluctuation is tested to be 0.6%, verifying the good stability of the laser operation. To the best of our knowledge, this is the highest average power of an ultrafast laser realized from an all-PM-fiber TDF-CPA system ever reported.

Lagrange tracking-based long-term drift trajectory prediction method for Autonomous Underwater Vehicle.

Autonomous Underwater Vehicle (AUV) works autonomously in complex marine environments. After a severe accident, an AUV will lose its power and rely on its small buoyancy to ascend at a slow speed. If the reserved buoyancy is insufficient, when reaching the thermocline, the buoyancy will rapidly decrease to zero. Consequently, the AUV will experience prolonged lateral drift within the thermocline. This study focuses on developing a prediction method for the drift trajectory of an AUV after a long-term power loss accident. The aim is to forecast the potential resurfacing location, providing technical support for surface search and salvage operations of the disabled AUV. To the best of our knowledge, currently, there is no mature and effective method for predicting long-term AUV underwater drift trajectories. In response to this issue, based on real AUV catastrophes, this paper studies the prediction of long-term AUV underwater drift trajectories in the cases of power loss. We propose a three-dimensional trajectory prediction method based on the Lagrange tracking approach. This method takes the AUV's longitudinal velocity, the time taken to reach different depths, and ocean current data at various depths into account. The reason for the AUV's failure to ascend to sea surface lies that the remaining buoyancy is too small to overcome the thermocline. As a result, AUV drifts long time within the thermocline. To address this issue, a method for estimating thermocline currents is proposed, which can be used to predict the lateral drift trajectory of the AUV within the thermocline. Simulation is conducted to compare the results obtained by the proposed method and that in a real accident. The results demonstrate that the proposed approach exhibits small directional and positional errors. This validates the effectiveness of the proposed method.