The piezoelectric effect is used in sensing applications such as in force and displacement sensors.However,the brittleness and low performance of piezoceramic lead zirconate titanate(PZT) often impede its applicabilit...The piezoelectric effect is used in sensing applications such as in force and displacement sensors.However,the brittleness and low performance of piezoceramic lead zirconate titanate(PZT) often impede its applicability in civil structures which are subjected to large loads.The concept of a piezocomposite electricity generating element(PCGE) has been proposed for improving the electricity generation performance and overcoming the brittleness of piezoceramic wafers.The post-curing residual stress in the PZT layer constitutes a main reason for the PCGE's enhanced performance,and the outer epoxy-based composites protect the brittle PZT layer.A d33-mode PCGE designed for bridge monitoring application was inserted in a bridge bearing to provide a permanent and simple weigh-in-motion system.The designed PCGEs were tested through a series of tests including fatigue and dynamic tests to verify their applicability for monitoring purposes in a bridge structure.A simple beam example was presented to show the applicability of the proposed bridge bearing equipped with the PCGE for adequately measuring the traffic loads.展开更多
The transistor-inspired Droplet-based Electricity Generator(DEG)significantly enhances the energy collection efficiency from single-position droplets.However,the design of the DEG arrays combining high output performa...The transistor-inspired Droplet-based Electricity Generator(DEG)significantly enhances the energy collection efficiency from single-position droplets.However,the design of the DEG arrays combining high output performance and large-scale integration under multi-position droplet impacts remains a challenge.Inspired by the unique structure of the honeycomb,we developed an Independent-Cell Droplet-based Electricity Generator(IC-DEG)array that allows for high-efficiency and stable droplet energy harvesting under multi-position droplet impacts.Each independent cell is a transistor-inspired Tubular Droplet-based Electricity Generator(T-DEG),which ensures the high electrical output of the IC-DEG array.The honeycomb-like arrangement improves the space utilization,accelerates the detachment of droplets,and avoids electrical interference among independent cells,all of which further enhance the IC-DEG array performance.The average peak open-circuit voltage of the IC-DEG array is 265.2 V,and 96.6%of peak voltages exceed 200 V,almost double that of a traditional planar array.Moreover,the average droplet detachment time of the IC-DEG array is 44.8 ms,41.4%shorter than the traditional planar array.The enhanced performance of the IC-DEG array is further demonstrated by the high speed of charging capacitors and the capability of driving electronic devices.This study provides a promising design concept for large-scale droplet energy harvesting devices.展开更多
The contact electrification(CE)between DI water and SiO_(2)or fluorinated polymer has been proven to be mainly due to electron transfer,which is significantly influenced by ions in solution.However,how these ions in w...The contact electrification(CE)between DI water and SiO_(2)or fluorinated polymer has been proven to be mainly due to electron transfer,which is significantly influenced by ions in solution.However,how these ions in water affect the charge transfer at the liquid-solid(L-S)interface is still unresolved,especially for the already charged friction layer.Here,a direct current droplet-based electricity generator(DC-DEG)which is sensitive to the change of charge transfer at the L-S interface is adopted to detect the effects of ions in the neutral salt solution on the charged PTFE surface.The distribution of ions on the charged L-S interface(the change of electric potential on the solid surface)and its effects on the output of DC-DEGs have been studied.The results indicate that the charge transfer of droplets and then the output of DC-DEGs are closely related to the concentrations of salt solutions.Anions can enhance the surface potential of PTFE due to their adsorptions on PFTE while cations can reduce it due to their screen effect.At low ionic concentrations,the surface potential enhancement caused by anion adsorption is larger than that surface potential reduction caused by screen effect from cations.At high ionic concentrations,the electrostatic screen effect of cations increases a lot to weaken the surface potential and reducing the charge separation of droplets induced by electrostatic induction(EI).This work explains the redistribution process of ions at the L-S interface and also provides a clever solution for improving the electrical output performance of DEGs.展开更多
Improving the specific,technical,economic,and environmental characteristics of piston engines(ICE)operating on alternative gaseous fuels is a pressing task for the energy and mechanical engineering industries.The aim ...Improving the specific,technical,economic,and environmental characteristics of piston engines(ICE)operating on alternative gaseous fuels is a pressing task for the energy and mechanical engineering industries.The aim of the study was to optimize the parameters of the ICE working cycle after replacing the base fuel(propane-butane blend)with syngas from wood sawdust to improve its technical and economic performance based on mathematical modeling.The modeling results were verified through experimental studies(differences for key parameters did not exceed 4.0%).The object of the study was an electric generator based on a single-cylinder spark ignition engine with a power of 1 kW.The article describes the main approaches to creating a mathematical model of the engine working cycle,a test bench for modeling verification,physicochemical properties of the base fuel(propane-butane blend),and laboratory syngas.It was shown that replacing the fuel from a propane-butane blend to laboratory syngas caused a decrease in engine efficiency to 33%(the efficiency of the base ICE was 0.179 vs.the efficiency of 0.119 for the converted ICE for the 0.59 kW power mode).Engine efficiency was chosen as the key criterion for optimizing the working cycle.As a result of optimization,the efficiency of the converted syngas engine was 6.1%higher than that of the base engine running on the propane-butane blend,and the power drop did not exceed 8.0%.Thus,careful fine-tuning of the working cycle parameters allows increasing the technical and economic characteristics of the syngas engine to the level of ICEs running on traditional types of fuel.展开更多
Efficiently reducing carbon dioxide(CO_(2))into carbon chemicals and fuels is highly desirable due to the rapid growth of atmospheric CO_(2)ncentration.In prior work,we described a unique H/CO_(2)fuel cell driven by l...Efficiently reducing carbon dioxide(CO_(2))into carbon chemicals and fuels is highly desirable due to the rapid growth of atmospheric CO_(2)ncentration.In prior work,we described a unique H/CO_(2)fuel cell driven by low-valued waste heat,which not only CO_(2)nverts CO_(2)to methane(CH_(4))but also outputs electrical energy,yet the CO_(2)reduction rate needs to be urgently improved.Here,a novel Ru-RuOcatalyst with heterostructure was grafted on mesoporous carbon spheres by in situ partially reducing RuOinto ultrasmall Ru clusters(~1 nm),in which heteroatom-doped carbon spheres as a matrix with excellent CO_(2)nductivity and abundant pores can not only easily CO_(2)nfine the formation of Ru nanocluster but also are beneficial to the exposed active sites of Ru CO_(2)mplex and the mass transport.CO_(2)mpared to pure RuOnanoparticles supported on carbon spheres,our CO_(2)mposite catalyst boosts the CO_(2) nversion rate by more than 5-fold,reaching a value of 382.7μmol gcat.h-1at 170℃.Moreover,a decent output power density of 2.92 W mwas obtained from this H2/CO_(2)fuel cell using Ru-RuOembedded carbon spheres as a cathode catalyst.The Ru-RuOheterostructure can modify the adsorption energy of CO_(2)and induce the redistribution of charge density,thus boosting CO_(2)reduction significantly.This work not only offers an efficient catalyst for this novel H_(2)/CO_(2)fuel cell but also presents a facile method to prepare Ru nanoclusters.展开更多
Under the influence of the rapid development of modern industry, the market demand for energy is increasing day by day, which makes the existing energy reserves decrease day by day. At present, the world's power e...Under the influence of the rapid development of modern industry, the market demand for energy is increasing day by day, which makes the existing energy reserves decrease day by day. At present, the world's power energy is mostly dependent on thermal power generation. However, the polluted dust and gas released from it will directly affect human health and the natural environment, which is contrary to the concept of sustainable development. Under this background, wind energy has attracted the attention of the energy market due to its renewable and pollution-free advantages. Especially under the background of increasingly mature wind power generation technology, the application rate of wind turbines has been gradually increased, effectively easing the pressure on electricity consumption in the market. In this regard, this paper will analyze the principle of wind power generation and the key points of wind power generation technology, aiming at promoting the promotion of economic and social benefits of wind power generation by improving the control degree of wind power application.展开更多
As the material basis of economic development, energy has an important impact on human existence. As a renewable energy, biomass power generation technology is an important support to help realize peak carbon dioxide ...As the material basis of economic development, energy has an important impact on human existence. As a renewable energy, biomass power generation technology is an important support to help realize peak carbon dioxide emissions and carbon neutrality. At present, remarkable achievements have been made in various aspects and it has gradually become a mature new energy power generation technology. For example, the effect of biomass straw power generation technology in low emission and zero emission is very remarkable. In China, biomass resources represented by straw and weeds are abundant, so the construction of biomass power generation project has resource advantages which can reduce the environmental burden and promote the construction of ecological civilization and agricultural development in China.展开更多
Under the strategic goal of sustainable development of national economy and society, with the continuous improvement of peoples living standard and the rapid growth of population, the corresponding amount of municipal...Under the strategic goal of sustainable development of national economy and society, with the continuous improvement of peoples living standard and the rapid growth of population, the corresponding amount of municipal solid waste is also increasing, resulting in increasingly prominent contradiction with consumption. Simple landfill disposal can no longer meet the needs of social development and environmental protection, so it is very necessary and feasible to build a power generation project of municipal solid waste incineration. Based on the requirements of domestic waste incineration power generation project, taking Dandong municipal domestic waste as an example, this paper introduces the necessity of power generation project construction.展开更多
This paper focuses on the simulation and test of the switched reluctance starter/generator systems. Through the emulational analysis of the initial starting torque, the optimal turn-on section of the power switches is...This paper focuses on the simulation and test of the switched reluctance starter/generator systems. Through the emulational analysis of the initial starting torque, the optimal turn-on section of the power switches is discovered. The fundamental theory of the generating operation is analyzed with the linearity model, and a new method is presented based on voltage pulse width modulation for the generating mode control. Through the steady-state and optimized emulation of the output power and system efficiency, the optimizational control approach for the generating mode over a wide speed range is introduced. At last, the test of the 3KW prototype system shows that the dynamic and static performance of this system is fine.展开更多
Starting with Faraday’s law of electromagnetic induction in 1831,electric(electromagnetic)machines have been developed ever since as“assembles”of electric and magnetic coupled circuits that convert mechanical to el...Starting with Faraday’s law of electromagnetic induction in 1831,electric(electromagnetic)machines have been developed ever since as“assembles”of electric and magnetic coupled circuits that convert mechanical to electrical energy(in generators)and vice versa(in motors),via magnetic energy storage.Generators and motors are reversible.The Maxwell four equations(laws)later in 19th Century have prompted the rapid development of all basic(DC.brush and travelling field AC machines by 1900.Then by 1930 AC(alternating current)power(energy)systems evolved by connecting in parallel electric synchronous generators(with voltage boost and buck electric transformers for efficient AC power transmission lines)of rather constant frequency and voltage,driven by turbines(prime movers)that harness fossil(coal,gas or nuclear fuels),thermal or hydro energy.The last 50 years have witnessed a dramatic extension of generators power/unit,renewable energy generators and of variable speed AC motor drives in applications with variable output such as ventilators,pumps compressors,conveyors,orr-mills,electric transport(mobility),industrial automation,robotics,home appliances and info-gadgets.This formidable development,required by the need of more but cleaner energy,was mainly driven by power electronics,better materials,better modeling,design methodologies and digital control.This humble inaugural overview attempts to combine a brief history of electrical generators and motors with recent progress and trends in their design and control,for representative applications.展开更多
The thermoelectric energy conversion technique by employing the Disk-Magnet Electromagnetic Induction (DM-EMI) and improved DM-EMIs is shown, and possible applications to heat engines as one of the energy harvesting t...The thermoelectric energy conversion technique by employing the Disk-Magnet Electromagnetic Induction (DM-EMI) and improved DM-EMIs is shown, and possible applications to heat engines as one of the energy harvesting technologies are also discussed. The idea is induced by integrating irreversible thermodynamical mechanism of a water drinking bird with that of a Stirling engine, resulting in thermoelectric energy generation different from conventional heat engines. The current thermoelectric energy conversion with DM-EMI can be applied to wide ranges of temperature differences. The mechanism of DM-EMI energy converter is examined in terms of axial flux magnetic lines and categorized as the axial flux generator. It is useful for practical applications to macroscopic heat engines such as wind, geothermal, thermal and nuclear power turbines and heat-dissipation lines, for supporting thermoelectric energy conversions. The technique of DM-EMI will contribute to environmental problems to maintain clean and susceptible energy as one of the energy harvesting technologies.展开更多
This paper presents the coucept of general and sensitive dimension, and also proposes the calculation formula of the general dimension least squares method. By calculating and analyzing the power spectrum and general ...This paper presents the coucept of general and sensitive dimension, and also proposes the calculation formula of the general dimension least squares method. By calculating and analyzing the power spectrum and general dimension from the fault sample, the relationship is achieved between sample status and the general dimension from vibration signals of the equipment so as to provide reference to fault diagnosis. Furthermore, a correlation function of general dimension is proposed, and calculations are carried out for a monitor signal and samples signal. The diagnosis method based on fractal theory is effective through the concrete examples of the steam electric generating set fault diagnosis, and the correlation coefficient of general dimension between a monitor signal and samples signal can improve the accuracy for fault diagnosis.展开更多
For solving the operation problems of floating liquefied natural gas(FLNG)vessels in harsh sea areas,especially in the areas where typhoon happens frequently,the characteristics of cyclone(typhoon)in China sea areas w...For solving the operation problems of floating liquefied natural gas(FLNG)vessels in harsh sea areas,especially in the areas where typhoon happens frequently,the characteristics of cyclone(typhoon)in China sea areas were analyzed based on the environmental conditions of the South China Sea.Then,the FLNG vessel connection operation and the FLNG vessel disconnection and evacuation plans in the situation of cyclones were compared.And finally,a series of research was carried out on the technical difficulties related to the FLNG vessel connection operation plan,such as the temperature field of LNG cofferdam,the vapor treatment and diffusion during a cyclone,such as a typhoon,and the typhoon generator at the shallow-water platform.Based on these analysis and research,the following recommendations were proposed.First,it is recommended to adopt the FLNG vessel connection operation plan during a typhoon to guarantee convenient and safe operation and to improve oil and gas field benefits.Second,a ballast cabin can be set inside the vessel to ensure the safety of Grade E steel in FLNG vessel,especially during a typhoon.Third,BOG diffusion can be still safe in the most dangerous working condition when the vent pipe reaches a certain height during a typhoon.Fourth,four groups of mooring systems(five pieces in each group)can be designed to guarantee the mooring strength of FLNG vessel connection operation during a typhoon.And fifth,when a typhoon arrives,it is necessary to stop FLNG production,release the pressure and organize personnel evacuation in a planned way.After the typhoon leaves,personnel return and FLNG production starts again.In this way,efficiency can be increased effectively,and the operational convenience and safety of FLNG vessels can be ensured.展开更多
In the Research Article,“All-Biobased Hydrovoltaic-Photovoltaic Electricity Generators for All-Weather Energy Harvesting”[1],the publisher inadvertently introduced an error in Fig.2F.The power density on the y-axis ...In the Research Article,“All-Biobased Hydrovoltaic-Photovoltaic Electricity Generators for All-Weather Energy Harvesting”[1],the publisher inadvertently introduced an error in Fig.2F.The power density on the y-axis was incorrectly labeled as(mW/cm^(2))instead of the correct(mW/m^(2)).Figure 2F has now been corrected in the PDF and HTML(full text).The layout of the figure panels has also been updated for better readability.展开更多
Harvesting water energy in various forms of water motion,such as evaporation,raindrops,river flows,ocean waves,and other,is promising to relieve the global energy crisis and reach the aim of carbon neutrality.However,...Harvesting water energy in various forms of water motion,such as evaporation,raindrops,river flows,ocean waves,and other,is promising to relieve the global energy crisis and reach the aim of carbon neutrality.However,this highly decentralized and distributed water energy poses a challenge on conventional electromagnetic hydropower technologies that feature centralization and scalization.Recently,this problem has been gradually addressed by the emergence of a myriad of electricity generators that take inspiration from natural living organisms,which have the capability to efficiently process and manage water and energy for survival in the natural competition.Imitating the liquid-solid behaviors manifested in ubiquitous biological processes,these generators allow for the efficient energy conversion from water-solid interaction into the charge transfer or electrical output under natural driving,such as gravity and solar power.However,in spite of the rapid development of the field,a fundamental understanding of these generators and their ability to bridge the gap between the fundamentals and the practical applications remains elusive.In this review,we first introduce the latest progress in the fundamental understanding in bio-inspired electricity generators that allow for efficient harvesting water energy in various forms,ranging from water evaporation,droplet to wave or flow,and then summarize the development of the engineering design of the various bio-inspired electricity generator in the practical applications,including self-powered sensor and wearable electronics.Finally,the prospects and urgent problems,such as how to achieve large-scale electricity generation,are presented.展开更多
Droplet-based electricity generators (DEGs) leveraging triboelectric effects are simple and high-performance devices for harvesting energy from ubiquitous water droplets. Instantaneous power plays a vital role in wide...Droplet-based electricity generators (DEGs) leveraging triboelectric effects are simple and high-performance devices for harvesting energy from ubiquitous water droplets. Instantaneous power plays a vital role in wide applications of DEGs. However, the governing law of the maximum instantaneous power and matching resistance is lacking and their determination suffers from heavy repetitive experiments, hindering the development of DEGs. Herein, we propose a quick evaluation method for the internal droplet impedance, instantaneous peak power, maximum instantaneous power and matching resistance which exhibits broad universality and excellent accuracy. Moreover, effects of diverse factors pertaining to droplets and devices are fully investigated, highlighting that the maximum instantaneous power and matching resistance can be effectively regulated across multiple orders of magnitudes by controlling the salt concentration. Our findings shed insights into the understanding, evaluation, and regulation of instantaneous power for DEGs, and shall promote the renovation of the DEG technology.展开更多
Sustainable power sources for outdoor wearable electronics are essential for the continuous operation of wearable devices.However,the current lack of engineering design that can harvest energy regardless of weather co...Sustainable power sources for outdoor wearable electronics are essential for the continuous operation of wearable devices.However,the current lack of engineering design that can harvest energy regardless of weather conditions presents a significant challenge.In this regard,this study introduces a wearable,breathable all-weather usable dual energy harvester(AWuDEH)that can seamlessly generate electrical energy regardless of weather conditions.In this study,the AWuDEH integrated with the thermoelectric generator and the droplet-based electricity generator is demonstrated.The AWuDEH,especially engineered with a bi-functional top substrate for radiative cooling and electrification,achieves sustainable energy harvesting outdoors,thereby addressing the conventional challenge associated with the necessity for separate energy harvesters tailored to outdoor usage contingent on weather conditions.The device reaches a maximum power output of 14.6μW cm^(-2)under simulated sunny conditions and generates a much more enhanced thermoelectric power of 74.78μW cm^(-2)and a droplet-based electric power of 256.25 mW m^(-2)in rainy conditions.As proof,this study developed self-powered wearable electronics capable of acquiring physiological signals in simulated outdoor scenarios.This study presents a promising advancement in wearable technology,offering a potent solution for sustainable energy harvesting independent of weather conditions.展开更多
Smart generators that collect energy from the ambient environment are a new approach for meeting growing global energy needs.Moisture is one of the most abundant resources in the ambient environment,and using it to ge...Smart generators that collect energy from the ambient environment are a new approach for meeting growing global energy needs.Moisture is one of the most abundant resources in the ambient environment,and using it to generate electricity has aroused great interest in recent years.In this review,we first summarize the emerging design principles of moisture power generation,including ion diffusion,streaming potential,and charged surface potential.Then,based on these fundamental principles,we systematically summarize the materials thus far known to be suitable for moisture power generation.Finally,we highlight the application of moisture energy generators in various fields,such as thermoelectricity,solar thermal evaporation,capacitors,strain sensors,and information storage,and discuss current challenges and future prospects for the development of moisture energy generators.展开更多
A brushless electrically excited synchronous generator （BEESG） with a hybrid rotor is a novel electrically excited synchronous generator. The BEESG proposed in this paper is composed of a conventional stator with tw...A brushless electrically excited synchronous generator （BEESG） with a hybrid rotor is a novel electrically excited synchronous generator. The BEESG proposed in this paper is composed of a conventional stator with two different sets of windings with different pole numbers, and a hybrid rotor with powerful coupling capacity. The pole number of the rotor is different from those of the stator windings. Thus, an analysis method different from that applied to conventional generators should be applied to the BEESG. In view of this problem, the equivalent circuit and electromagnetic torque expression of the BEESG are derived on the basis of electromagnetic relation of the proposed generator. The generator is simulated and tested experimentally using the established equivalent circuit model. The experimental and simulation data are then analyzed and compared. Results show the validity of the equivalent circuit model.展开更多
An actively mode-locked laser with tunable repetition rate is proposed and experimentally demonstrated based on a programmable electrical pattern generator. By changing the repetition rate of the electrical patterns a...An actively mode-locked laser with tunable repetition rate is proposed and experimentally demonstrated based on a programmable electrical pattern generator. By changing the repetition rate of the electrical patterns applied on the in-cavity modulator, the repetition rate of the output optical pulse sequences changes accordingly while the pulse width of the optical pulse train remains almost constant. In other words, the output ultra-short pulse train has a tunable duty cycle. In a proof-of-principle experiment, optical pulses with repetition rates of 10, 5, 2.5 and 1.25 GHz are obtained by adjusting the electrical pattern applied on the in-cavity modulator while their pulse widths remain almost unchanged.展开更多
基金Project supported by Konkuk University,Korea,in 2014
文摘The piezoelectric effect is used in sensing applications such as in force and displacement sensors.However,the brittleness and low performance of piezoceramic lead zirconate titanate(PZT) often impede its applicability in civil structures which are subjected to large loads.The concept of a piezocomposite electricity generating element(PCGE) has been proposed for improving the electricity generation performance and overcoming the brittleness of piezoceramic wafers.The post-curing residual stress in the PZT layer constitutes a main reason for the PCGE's enhanced performance,and the outer epoxy-based composites protect the brittle PZT layer.A d33-mode PCGE designed for bridge monitoring application was inserted in a bridge bearing to provide a permanent and simple weigh-in-motion system.The designed PCGEs were tested through a series of tests including fatigue and dynamic tests to verify their applicability for monitoring purposes in a bridge structure.A simple beam example was presented to show the applicability of the proposed bridge bearing equipped with the PCGE for adequately measuring the traffic loads.
基金supported by the National Key R&D Program of China(2022YFB4602401)the National Natural Science Foundation of China(52075071).
文摘The transistor-inspired Droplet-based Electricity Generator(DEG)significantly enhances the energy collection efficiency from single-position droplets.However,the design of the DEG arrays combining high output performance and large-scale integration under multi-position droplet impacts remains a challenge.Inspired by the unique structure of the honeycomb,we developed an Independent-Cell Droplet-based Electricity Generator(IC-DEG)array that allows for high-efficiency and stable droplet energy harvesting under multi-position droplet impacts.Each independent cell is a transistor-inspired Tubular Droplet-based Electricity Generator(T-DEG),which ensures the high electrical output of the IC-DEG array.The honeycomb-like arrangement improves the space utilization,accelerates the detachment of droplets,and avoids electrical interference among independent cells,all of which further enhance the IC-DEG array performance.The average peak open-circuit voltage of the IC-DEG array is 265.2 V,and 96.6%of peak voltages exceed 200 V,almost double that of a traditional planar array.Moreover,the average droplet detachment time of the IC-DEG array is 44.8 ms,41.4%shorter than the traditional planar array.The enhanced performance of the IC-DEG array is further demonstrated by the high speed of charging capacitors and the capability of driving electronic devices.This study provides a promising design concept for large-scale droplet energy harvesting devices.
基金supported by the National Natural Science Foundation of China(Grant No.12074321).
文摘The contact electrification(CE)between DI water and SiO_(2)or fluorinated polymer has been proven to be mainly due to electron transfer,which is significantly influenced by ions in solution.However,how these ions in water affect the charge transfer at the liquid-solid(L-S)interface is still unresolved,especially for the already charged friction layer.Here,a direct current droplet-based electricity generator(DC-DEG)which is sensitive to the change of charge transfer at the L-S interface is adopted to detect the effects of ions in the neutral salt solution on the charged PTFE surface.The distribution of ions on the charged L-S interface(the change of electric potential on the solid surface)and its effects on the output of DC-DEGs have been studied.The results indicate that the charge transfer of droplets and then the output of DC-DEGs are closely related to the concentrations of salt solutions.Anions can enhance the surface potential of PTFE due to their adsorptions on PFTE while cations can reduce it due to their screen effect.At low ionic concentrations,the surface potential enhancement caused by anion adsorption is larger than that surface potential reduction caused by screen effect from cations.At high ionic concentrations,the electrostatic screen effect of cations increases a lot to weaken the surface potential and reducing the charge separation of droplets induced by electrostatic induction(EI).This work explains the redistribution process of ions at the L-S interface and also provides a clever solution for improving the electrical output performance of DEGs.
基金the Ministry of Science and Higher Education of the Russian Federation(Ural Federal University Program of Development within the Priority-2030 Program)is gratefully acknowledged.
文摘Improving the specific,technical,economic,and environmental characteristics of piston engines(ICE)operating on alternative gaseous fuels is a pressing task for the energy and mechanical engineering industries.The aim of the study was to optimize the parameters of the ICE working cycle after replacing the base fuel(propane-butane blend)with syngas from wood sawdust to improve its technical and economic performance based on mathematical modeling.The modeling results were verified through experimental studies(differences for key parameters did not exceed 4.0%).The object of the study was an electric generator based on a single-cylinder spark ignition engine with a power of 1 kW.The article describes the main approaches to creating a mathematical model of the engine working cycle,a test bench for modeling verification,physicochemical properties of the base fuel(propane-butane blend),and laboratory syngas.It was shown that replacing the fuel from a propane-butane blend to laboratory syngas caused a decrease in engine efficiency to 33%(the efficiency of the base ICE was 0.179 vs.the efficiency of 0.119 for the converted ICE for the 0.59 kW power mode).Engine efficiency was chosen as the key criterion for optimizing the working cycle.As a result of optimization,the efficiency of the converted syngas engine was 6.1%higher than that of the base engine running on the propane-butane blend,and the power drop did not exceed 8.0%.Thus,careful fine-tuning of the working cycle parameters allows increasing the technical and economic characteristics of the syngas engine to the level of ICEs running on traditional types of fuel.
基金financially supported by the Natural Science Foundation of Shaanxi Provincial(2021JQ-034)Chongqing University Key Laboratory of Micro/Nano Materials Engineering and Technology(KFJJ2012)by University Joint Project of Shaanxi Province(2021GXLH-Z-067)。
文摘Efficiently reducing carbon dioxide(CO_(2))into carbon chemicals and fuels is highly desirable due to the rapid growth of atmospheric CO_(2)ncentration.In prior work,we described a unique H/CO_(2)fuel cell driven by low-valued waste heat,which not only CO_(2)nverts CO_(2)to methane(CH_(4))but also outputs electrical energy,yet the CO_(2)reduction rate needs to be urgently improved.Here,a novel Ru-RuOcatalyst with heterostructure was grafted on mesoporous carbon spheres by in situ partially reducing RuOinto ultrasmall Ru clusters(~1 nm),in which heteroatom-doped carbon spheres as a matrix with excellent CO_(2)nductivity and abundant pores can not only easily CO_(2)nfine the formation of Ru nanocluster but also are beneficial to the exposed active sites of Ru CO_(2)mplex and the mass transport.CO_(2)mpared to pure RuOnanoparticles supported on carbon spheres,our CO_(2)mposite catalyst boosts the CO_(2) nversion rate by more than 5-fold,reaching a value of 382.7μmol gcat.h-1at 170℃.Moreover,a decent output power density of 2.92 W mwas obtained from this H2/CO_(2)fuel cell using Ru-RuOembedded carbon spheres as a cathode catalyst.The Ru-RuOheterostructure can modify the adsorption energy of CO_(2)and induce the redistribution of charge density,thus boosting CO_(2)reduction significantly.This work not only offers an efficient catalyst for this novel H_(2)/CO_(2)fuel cell but also presents a facile method to prepare Ru nanoclusters.
文摘Under the influence of the rapid development of modern industry, the market demand for energy is increasing day by day, which makes the existing energy reserves decrease day by day. At present, the world's power energy is mostly dependent on thermal power generation. However, the polluted dust and gas released from it will directly affect human health and the natural environment, which is contrary to the concept of sustainable development. Under this background, wind energy has attracted the attention of the energy market due to its renewable and pollution-free advantages. Especially under the background of increasingly mature wind power generation technology, the application rate of wind turbines has been gradually increased, effectively easing the pressure on electricity consumption in the market. In this regard, this paper will analyze the principle of wind power generation and the key points of wind power generation technology, aiming at promoting the promotion of economic and social benefits of wind power generation by improving the control degree of wind power application.
文摘As the material basis of economic development, energy has an important impact on human existence. As a renewable energy, biomass power generation technology is an important support to help realize peak carbon dioxide emissions and carbon neutrality. At present, remarkable achievements have been made in various aspects and it has gradually become a mature new energy power generation technology. For example, the effect of biomass straw power generation technology in low emission and zero emission is very remarkable. In China, biomass resources represented by straw and weeds are abundant, so the construction of biomass power generation project has resource advantages which can reduce the environmental burden and promote the construction of ecological civilization and agricultural development in China.
文摘Under the strategic goal of sustainable development of national economy and society, with the continuous improvement of peoples living standard and the rapid growth of population, the corresponding amount of municipal solid waste is also increasing, resulting in increasingly prominent contradiction with consumption. Simple landfill disposal can no longer meet the needs of social development and environmental protection, so it is very necessary and feasible to build a power generation project of municipal solid waste incineration. Based on the requirements of domestic waste incineration power generation project, taking Dandong municipal domestic waste as an example, this paper introduces the necessity of power generation project construction.
文摘This paper focuses on the simulation and test of the switched reluctance starter/generator systems. Through the emulational analysis of the initial starting torque, the optimal turn-on section of the power switches is discovered. The fundamental theory of the generating operation is analyzed with the linearity model, and a new method is presented based on voltage pulse width modulation for the generating mode control. Through the steady-state and optimized emulation of the output power and system efficiency, the optimizational control approach for the generating mode over a wide speed range is introduced. At last, the test of the 3KW prototype system shows that the dynamic and static performance of this system is fine.
文摘Starting with Faraday’s law of electromagnetic induction in 1831,electric(electromagnetic)machines have been developed ever since as“assembles”of electric and magnetic coupled circuits that convert mechanical to electrical energy(in generators)and vice versa(in motors),via magnetic energy storage.Generators and motors are reversible.The Maxwell four equations(laws)later in 19th Century have prompted the rapid development of all basic(DC.brush and travelling field AC machines by 1900.Then by 1930 AC(alternating current)power(energy)systems evolved by connecting in parallel electric synchronous generators(with voltage boost and buck electric transformers for efficient AC power transmission lines)of rather constant frequency and voltage,driven by turbines(prime movers)that harness fossil(coal,gas or nuclear fuels),thermal or hydro energy.The last 50 years have witnessed a dramatic extension of generators power/unit,renewable energy generators and of variable speed AC motor drives in applications with variable output such as ventilators,pumps compressors,conveyors,orr-mills,electric transport(mobility),industrial automation,robotics,home appliances and info-gadgets.This formidable development,required by the need of more but cleaner energy,was mainly driven by power electronics,better materials,better modeling,design methodologies and digital control.This humble inaugural overview attempts to combine a brief history of electrical generators and motors with recent progress and trends in their design and control,for representative applications.
文摘The thermoelectric energy conversion technique by employing the Disk-Magnet Electromagnetic Induction (DM-EMI) and improved DM-EMIs is shown, and possible applications to heat engines as one of the energy harvesting technologies are also discussed. The idea is induced by integrating irreversible thermodynamical mechanism of a water drinking bird with that of a Stirling engine, resulting in thermoelectric energy generation different from conventional heat engines. The current thermoelectric energy conversion with DM-EMI can be applied to wide ranges of temperature differences. The mechanism of DM-EMI energy converter is examined in terms of axial flux magnetic lines and categorized as the axial flux generator. It is useful for practical applications to macroscopic heat engines such as wind, geothermal, thermal and nuclear power turbines and heat-dissipation lines, for supporting thermoelectric energy conversions. The technique of DM-EMI will contribute to environmental problems to maintain clean and susceptible energy as one of the energy harvesting technologies.
文摘This paper presents the coucept of general and sensitive dimension, and also proposes the calculation formula of the general dimension least squares method. By calculating and analyzing the power spectrum and general dimension from the fault sample, the relationship is achieved between sample status and the general dimension from vibration signals of the equipment so as to provide reference to fault diagnosis. Furthermore, a correlation function of general dimension is proposed, and calculations are carried out for a monitor signal and samples signal. The diagnosis method based on fractal theory is effective through the concrete examples of the steam electric generating set fault diagnosis, and the correlation coefficient of general dimension between a monitor signal and samples signal can improve the accuracy for fault diagnosis.
文摘For solving the operation problems of floating liquefied natural gas(FLNG)vessels in harsh sea areas,especially in the areas where typhoon happens frequently,the characteristics of cyclone(typhoon)in China sea areas were analyzed based on the environmental conditions of the South China Sea.Then,the FLNG vessel connection operation and the FLNG vessel disconnection and evacuation plans in the situation of cyclones were compared.And finally,a series of research was carried out on the technical difficulties related to the FLNG vessel connection operation plan,such as the temperature field of LNG cofferdam,the vapor treatment and diffusion during a cyclone,such as a typhoon,and the typhoon generator at the shallow-water platform.Based on these analysis and research,the following recommendations were proposed.First,it is recommended to adopt the FLNG vessel connection operation plan during a typhoon to guarantee convenient and safe operation and to improve oil and gas field benefits.Second,a ballast cabin can be set inside the vessel to ensure the safety of Grade E steel in FLNG vessel,especially during a typhoon.Third,BOG diffusion can be still safe in the most dangerous working condition when the vent pipe reaches a certain height during a typhoon.Fourth,four groups of mooring systems(five pieces in each group)can be designed to guarantee the mooring strength of FLNG vessel connection operation during a typhoon.And fifth,when a typhoon arrives,it is necessary to stop FLNG production,release the pressure and organize personnel evacuation in a planned way.After the typhoon leaves,personnel return and FLNG production starts again.In this way,efficiency can be increased effectively,and the operational convenience and safety of FLNG vessels can be ensured.
文摘In the Research Article,“All-Biobased Hydrovoltaic-Photovoltaic Electricity Generators for All-Weather Energy Harvesting”[1],the publisher inadvertently introduced an error in Fig.2F.The power density on the y-axis was incorrectly labeled as(mW/cm^(2))instead of the correct(mW/m^(2)).Figure 2F has now been corrected in the PDF and HTML(full text).The layout of the figure panels has also been updated for better readability.
基金We acknowledge the financial support from the National Natural Science Foundation of China(No.51975502)Shenzhen Science and Technology Innovation Council(Nos.SGDX20201103093005028 and JCYJ20200109143206663)Research Grants Council of Hong Kong(Nos.C1006-20WF,11213320,and 11219219),and the Health@InnoHK(Hong Kong Centre for Cerebro-cardiovascular Health Engineering(COCHE)).
文摘Harvesting water energy in various forms of water motion,such as evaporation,raindrops,river flows,ocean waves,and other,is promising to relieve the global energy crisis and reach the aim of carbon neutrality.However,this highly decentralized and distributed water energy poses a challenge on conventional electromagnetic hydropower technologies that feature centralization and scalization.Recently,this problem has been gradually addressed by the emergence of a myriad of electricity generators that take inspiration from natural living organisms,which have the capability to efficiently process and manage water and energy for survival in the natural competition.Imitating the liquid-solid behaviors manifested in ubiquitous biological processes,these generators allow for the efficient energy conversion from water-solid interaction into the charge transfer or electrical output under natural driving,such as gravity and solar power.However,in spite of the rapid development of the field,a fundamental understanding of these generators and their ability to bridge the gap between the fundamentals and the practical applications remains elusive.In this review,we first introduce the latest progress in the fundamental understanding in bio-inspired electricity generators that allow for efficient harvesting water energy in various forms,ranging from water evaporation,droplet to wave or flow,and then summarize the development of the engineering design of the various bio-inspired electricity generator in the practical applications,including self-powered sensor and wearable electronics.Finally,the prospects and urgent problems,such as how to achieve large-scale electricity generation,are presented.
基金financial support from the China Postdoctoral Science Foundation(No.2023TQ0210)the Postdoctoral Fellowship Program of CPSF(No.GZB20230403)+1 种基金the Fundamental Research Funds for the Central Universities(Shanghai Jiao Tong University)the Innovative Research Groups of the National Natural Science Foundation of China(No.51521004)。
文摘Droplet-based electricity generators (DEGs) leveraging triboelectric effects are simple and high-performance devices for harvesting energy from ubiquitous water droplets. Instantaneous power plays a vital role in wide applications of DEGs. However, the governing law of the maximum instantaneous power and matching resistance is lacking and their determination suffers from heavy repetitive experiments, hindering the development of DEGs. Herein, we propose a quick evaluation method for the internal droplet impedance, instantaneous peak power, maximum instantaneous power and matching resistance which exhibits broad universality and excellent accuracy. Moreover, effects of diverse factors pertaining to droplets and devices are fully investigated, highlighting that the maximum instantaneous power and matching resistance can be effectively regulated across multiple orders of magnitudes by controlling the salt concentration. Our findings shed insights into the understanding, evaluation, and regulation of instantaneous power for DEGs, and shall promote the renovation of the DEG technology.
基金supported by the National Research Foundation of Korea(NRF)(RS-2024-00343512,RS-2024-00416938).
文摘Sustainable power sources for outdoor wearable electronics are essential for the continuous operation of wearable devices.However,the current lack of engineering design that can harvest energy regardless of weather conditions presents a significant challenge.In this regard,this study introduces a wearable,breathable all-weather usable dual energy harvester(AWuDEH)that can seamlessly generate electrical energy regardless of weather conditions.In this study,the AWuDEH integrated with the thermoelectric generator and the droplet-based electricity generator is demonstrated.The AWuDEH,especially engineered with a bi-functional top substrate for radiative cooling and electrification,achieves sustainable energy harvesting outdoors,thereby addressing the conventional challenge associated with the necessity for separate energy harvesters tailored to outdoor usage contingent on weather conditions.The device reaches a maximum power output of 14.6μW cm^(-2)under simulated sunny conditions and generates a much more enhanced thermoelectric power of 74.78μW cm^(-2)and a droplet-based electric power of 256.25 mW m^(-2)in rainy conditions.As proof,this study developed self-powered wearable electronics capable of acquiring physiological signals in simulated outdoor scenarios.This study presents a promising advancement in wearable technology,offering a potent solution for sustainable energy harvesting independent of weather conditions.
基金This work has been supported by the Chang Jiang Scholars Program and the Innovation Program of Shanghai Municipal Education Commission(2019-01-07-00-03-E00023)to Prof.Xiaohong QinYoung Elite Scientists Sponsorship Program by CAST to Prof.Liming Wang+1 种基金Shanghai Pujiang Program(21PJ1400200)to Prof.Dongxiao JiDHU Distinguished Young Professor Program to Prof.Liming Wang and Prof.Dongxiao Ji.
文摘Smart generators that collect energy from the ambient environment are a new approach for meeting growing global energy needs.Moisture is one of the most abundant resources in the ambient environment,and using it to generate electricity has aroused great interest in recent years.In this review,we first summarize the emerging design principles of moisture power generation,including ion diffusion,streaming potential,and charged surface potential.Then,based on these fundamental principles,we systematically summarize the materials thus far known to be suitable for moisture power generation.Finally,we highlight the application of moisture energy generators in various fields,such as thermoelectricity,solar thermal evaporation,capacitors,strain sensors,and information storage,and discuss current challenges and future prospects for the development of moisture energy generators.
基金This work was supported by the Key Projects of the National Natural Science Foundation of China （Grant No. 51537007） and the National Natural Science Foundation of China （Grant No. 51277125）.
文摘A brushless electrically excited synchronous generator （BEESG） with a hybrid rotor is a novel electrically excited synchronous generator. The BEESG proposed in this paper is composed of a conventional stator with two different sets of windings with different pole numbers, and a hybrid rotor with powerful coupling capacity. The pole number of the rotor is different from those of the stator windings. Thus, an analysis method different from that applied to conventional generators should be applied to the BEESG. In view of this problem, the equivalent circuit and electromagnetic torque expression of the BEESG are derived on the basis of electromagnetic relation of the proposed generator. The generator is simulated and tested experimentally using the established equivalent circuit model. The experimental and simulation data are then analyzed and compared. Results show the validity of the equivalent circuit model.
基金supported by the National Natural Science Foundation of China (No.60607008)the National "863" Program of China (No.2007AA01Z271)
文摘An actively mode-locked laser with tunable repetition rate is proposed and experimentally demonstrated based on a programmable electrical pattern generator. By changing the repetition rate of the electrical patterns applied on the in-cavity modulator, the repetition rate of the output optical pulse sequences changes accordingly while the pulse width of the optical pulse train remains almost constant. In other words, the output ultra-short pulse train has a tunable duty cycle. In a proof-of-principle experiment, optical pulses with repetition rates of 10, 5, 2.5 and 1.25 GHz are obtained by adjusting the electrical pattern applied on the in-cavity modulator while their pulse widths remain almost unchanged.
