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[en] In this research, an export coefficient based dual inexact two-stage stochastic credibility constrained programming (ECDITSCCP) model was developed through integrating an improved export coefficient model (ECM), interval linear programming (ILP), fuzzy credibility constrained programming (FCCP) and a fuzzy expected value equation within a general two stage programming (TSP) framework. The proposed ECDITSCCP model can effectively address multiple uncertainties expressed as random variables, fuzzy numbers, pure and dual intervals. Also, the model can provide a direct linkage between pre-regulated management policies and the associated economic implications. Moreover, the solutions under multiple credibility levels can be obtained for providing potential decision alternatives for decision makers. The proposed model was then applied to identify optimal land use structures for agricultural NPS pollution mitigation in a representative upstream subcatchment of the Miyun Reservoir watershed in north China. Optimal solutions of the model were successfully obtained, indicating desired land use patterns and nutrient discharge schemes to get a maximum agricultural system benefits under a limited discharge permit. Also, numerous results under multiple credibility levels could provide policy makers with several options, which could help get an appropriate balance between system benefits and pollution mitigation. The developed ECDITSCCP model can be effectively applied to addressing the uncertain information in agricultural systems and shows great applicability to the land use adjustment for agricultural NPS pollution mitigation. - Highlights: • An export coefficient based optimization model was developed in this research. • The model can deal with uncertainties associated with agricultural system. • The model can be utilized to support agricultural NPS pollution mitigation. • Desired land use patterns and nutrient discharge schemes can be obtained.
[en] Highlights: • The first effort to forecast potential sensor applications of TENGs through Tech Mining methods. • Sensor applications of TENGs were identified on 4 levels: usage scenarios, sub-technology, technology and industry. • Researchers should widen interdisciplinary collaboration, pursue connections with industry, and file more patents. The Triboelectric Nanogenerator (TENG), invented in 2012, is an emerging energy harvesting technology that efficiently converts ambient mechanical energy into electricity. Much work has been done to develop this device and improve its performance. However, no systematic report about its applications through large-scale publication and patent data analysis is available. In this study, we use “Tech Mining,” a systematic analytical method based on structured texts applied to publication and patent abstract data, to analyze potential applications of TENGs. A series of applications from product scale to industry scale are identified. The findings show that when used as sensors, TENGs are mostly applicable in automation and energy-intensive industries such as automotive, medical or surgical devices, consumer electronics and household appliances. TENGs in the form of sensors can also be integrated with future-oriented and exponentially growing technologies such as robotics, drones, nanotechnology, and bioinformatics that will create enormous value for future economies. Moreover, applications of TENGs as sensors are also in line with current global trends of science and technology development, including the “Internet of Things,” big data, clean energy, and smart cities. Combined with those technologies and industries, TENGs can help in tackling challenges of global warming, environmental pollution and security systems. We suggest the TENG research community to widen interdisciplinary collaboration, pursue connections with industry, and file more patents as R&D progresses. In addition, research limitations and future development directions of TENG are pointed out.
[en] Highlights: • High-density TENG units integrated in the device for water wave energy harvesting. • Air-driven membrane structures for effectively transferring and distributing harvested energy. • Tunable resonate state achieved with a spring-levitated oscillator structure. • Demonstrating excellent output performance and extraordinary scalability. Water wave energy is considered a promising renewable energy source, while currently little has been exploited due to a number of unsolved challenges for present technologies. The triboelectric nanogenerator (TENG), as an emerging energy harvesting technology, shows particular advantages in transforming low frequency mechanical energy into electricity, providing new opportunities for harvesting water wave energy. In this work, an integrated triboelectric nanogenerator array device based on air-driven membrane structures is demonstrated. With novel designs of a spring-levitated oscillator structure and a mechanism to use air pressure to transfer and distribute harvested water wave energy, the device can drive a series of integrated TENG units effectively and simultaneously. While operating at low frequency near the resonant frequency of about 2.9 Hz, the device integrating 38 TENG units shows high output of transferred charges per cycle of 15 μC, short-circuit current of 187 μA and optimized peak power density of 13.23 W m−3. The device can easily integrates large-scale high-density TENG arrays in one package, as can greatly augment the output, providing a promising route to effectively harvest water wave energy for various practical applications.
[en] We study the structure of locational marginal prices in day-ahead and real-time wholesale electricity markets. In particular, we consider the case of two North American markets and show that the price correlations contain information on the locational structure of the grid. We study various clustering methods and introduce a type of correlation function based on event synchronization for spiky time series, and another based on string correlations of location names provided by the markets. As a result, this allows us to reconstruct aspects of the locational structure of the grid.
[en] Highlights: • Recent progress in blue energy harvesting with TENG technology is reviewed. • The fundamental physics mechanism of nanogenerators is the Maxwell's displacement current. • The TENG network is proposed for large-scale blue energy harvesting. Widely distributed across the globe, water wave energy is one of the most promising renewable energy sources, while little has been exploited due to various limitations of current technologies mainly relying on electromagnetic generator (EMG), especially its operation in irregular environment and low frequency (the energy for the new era – the era of internet of things.
[en] Highlights: • The hybrid nanogenerator can obtain both mechanical and heat energy from the same energy source. • It realizes advantage complementary by combining high voltage of TENG and high current of TEG. • The hybridized nanogenerator can act as sustainable power source to drive commercial electronics. • The system exhibits high removal efficiency of 92.1% for PM2.5 and implements real-time gas quality monitoring. Rapid urbanization and industrialization causes huge energy consumption, bringing about a variety of air pollution issue due to the massive exhaust gas emitted from factories, power plants, traffic, etc. While normal supply of fossil fuels is ensured, the task of achieving energy saving and emission reduction is very taxing. It's an optimal option to further control exhaust gas through effectively recycling industrial exhaust gas energy. Here, a hybrid nanogenerator composed of a triboelectric nanogenerator (TENG) and thermoelectric generator (TEG) has been proposed for gas energy recycle and purification. Both mechanical and heat energy of exhaust gas can be recycled by combining the merits of TENG and TEG which achieves advantage complementary. It delivers an regulated power of 147.6 W m−3, which is capable of powering electronic devices and being stored up. Moreover, exhaust gas purification is implemented through reclaiming exhaust gas energy with no external power. It obtains high removal efficiency of 92.1% for PM2.5 and realizes real-time gas quality monitoring. This work has potential application prospect to serve for large-scale industrial exhuast gas recycle and treatment equipments which help reduce resource consumption and relax environmental problems.
[en] Existing literature in people’s attitude toward nanotechnology and acceptance of nanotechnology applications has generally investigated the impact of factors at the individual or context levels. While this vast body of research is very informative, a comprehensive understanding of how attitude toward nanotechnology are formed and factors influencing the acceptance of nanotechnology are elusive. This paper proposes an exploratory nanotechnology perception-attitude-acceptance framework (Nano-PAAF) to build a systematic understanding of the phenomenon. The framework proposes that perceptions of risks and benefits of nanotechnology are influenced by cognitive, affective, and sociocultural factors. The sociodemographic factors of consumers and contextual factors mitigate the influence of cognitive, affective, and sociocultural factors on the perception of risks and benefits. The perceived risks and benefits in turn influence people’s attitude toward nanotechnology, which then influences acceptance of nanotechnology products. This framework will need further development over time to incorporate emerging knowledge and is expected to be useful for researchers, decision and policy makers, industry, and business entities.
[en] Emission reduction is one of the most efficient control measures in fuel-powered locomotives. The purpose of this study was to determine the reduction in particulate matter (PM) and black carbon (BC) emissions following the installation of a fuel activation device (FAD). The FAD was developed to enhance fuel combustion by atomizing fuel and to increase the surface area per unit volume of injected fuel. Emission reduction by the FAD was evaluated by installing a FAD in an operating diesel locomotive in Mongolia. The test was conducted on a train operating on a round-trip 238-km route between Ulaanbaatar and Choir stations in Mongolia. The fuel consumption rate was slightly reduced following the FAD installation. The FAD installation decreased PM and BC emissions in the diesel locomotive, especially coarse PM. The PM10 reductions achieved after FAD installation were 58.0, 69.7, and 34.2% for the constant velocity, stopping, and acceleration stages of the train's operation, respectively. The BC reduction rates were 29.5, 52.8, and 27.4% for the constant velocity, stopping, and acceleration stages, respectively. - Highlights: • The FAD was developed to enhance fuel combustion by increasing the surface area per unit volume of injected fuel. • Emission reduction by the FAD was evaluated by installing a FAD in an operating diesel locomotive in Mongolia. • Under all operating conditions, the reduction efficiency increased as the particle diameter increased. • The FAD installation decreased PM and BC emissions from the diesel locomotives, especially for coarse PM.
[en] Life Cycle Assessment (LCA) has been used to assess the environmental sustainability of the chlor-alkali production in Europe. The three current technologies applied nowadays are mercury, diaphragm, and membrane cell technology. Despite, having achieved higher energy efficiencies since the introduction of membrane technology, energy consumption is still one of the most important issues in this sector. An emerging technology namely oxygen-depolarised cathodes (ODC) is suggested as a promising approach for reducing the electrolysis energy demand. However, its requirement of pure oxygen and the lack of production of hydrogen, which could otherwise be valorised, are controversial features for greener chlorine production. The aim of this work is to evaluate and compare the environmental profiles of the current and emerging technologies for chlorine production and to identify the main hot spots of the process. Salt mining, brine preparation, electrolysis technology and products treatment are included inside the system boundaries. Twelve environmental impact categories grouped into natural resources usage and environmental burdens are assessed from cradle to gate and further normalised and weighted. Furthermore, hydrogen valorisation, current density and allocation procedure are subjected to sensitivity analysis. Results show that the electrolysis stage is the main contributor to the environmental impacts due to energy consumption, causing 99.5–72% of these impacts. Mercury is the less environmentally sustainable technology, closely followed by diaphragm. This difference becomes bigger after normalisation, owing to hazardous waste generated by mercury technique. Conversely, best results are obtained for ODC instead of membrane scenario, although the reduction in energy requirements is lesser than expected (7%). - Highlights: • Environmental profile of emerging vs current chlor-akali technologies • LCA approach based on natural resources and environmental burdens methodology • Majority of impacts due to energy consumption in electrolysis stage • Hydrogen valorisation through electricity generation to tackle energy dependency • Expected results for emergent technology worsen due to lack of hydrogen production.
[en] Highlights: • A spring is introduced into the TENG for harvesting water wave energy. • The spring can translate the low frequency motion into a high frequency motion. • By using the spring, the energy conversion efficiency can be enhanced by 150.3%. Ocean waves are one of the most promising renewable energy sources for large-scope applications. Triboelectric nanogenerator (TENG) has been demonstrated to effectively harvest water wave energy possibly toward large-scale blue energy. In this work, a kind of spring-assisted TENG was designed and investigated for harvesting water wave energy. The idea of introducing spring is to store the potential energy built during mechanical triggering for multiple cycles of conversion into electricity afterward, and transform a low frequency motion into a high frequency oscillation for improving the energy harvesting efficiency. The output performance of the basic unit was optimized by adjusting the motor acceleration and spring parameters including the rigidity and length. There exists an optimized spring rigidity or spring length to produce the highest performance. By using the spring, the accumulated charge of the TENG can be increased by 113.0%, and the translated electric energy or efficiency can be improved by 150.3%. Then four optimized basic units were connected in parallel and packaged into a sealed box to harvest the water wave energy. The present work could provide an approach to improving the output performance and efficiency of TENGs in harvesting low-frequency water wave energy.