Pumping Strategy Research Articles

A Reduced Order Model for Sea Water Intrusion Simulation Using Proper Orthogonal Decomposition.

Sea water intrusion (SWI) simulators are essential tools to assist the sustainable management of coastal aquifers. These simulators require the solution of coupled variable-density partial differential equations (PDEs), which reproduce the processes of groundwater flow and dissolved salt transport. The solution of these PDEs is typically addressed numerically with the use of density-dependent flow simulators, which are computationally intensive in most practical applications. To this end, model surrogates are generally developed as substitutes for full-scale aquifer models to trade off accuracy in exchange for computational efficiency. Surrogates represent an attractive option to support groundwater management situations in which fast simulators are required to evaluate large sets of alternative pumping strategies. Reduced-order models, a sub-category of surrogate models, are based on the original model equations and may provide quite accurate results at a small fraction of computational cost. In this study, a variable-density flow reduced-order model based on proper orthogonal decomposition (POD) and utilizing a fully coupled flow and solute-transport model is implemented with a finite-difference (FD) approach for simulating SWI in coastal aquifers. The accuracy and computational efficiency of the FD-POD approach for both homogeneous and-more realistic-heterogeneous systems are investigated using test cases based on the classic Henry's problem (Henry 1964). The findings demonstrate that the combined FD-POD approach is effective in terms of both accuracy and computational gain and can accommodate the output of the most popular variable-density flow models, such as those from USGS's MODFLOW family.

Ultrabroadband chromaticity-programmable random lasing based on waveguide-assisted pumping strategy

Chromaticity-tunable random lasers (RLs) have wide applications in laser display and imaging. However, the achievable chromaticity range poses challenges due to their inherent randomness and the inevitable loss. Here, an ultrabroadband chromaticity-programmable RL has been demonstrated via waveguide-assisted pumping strategy. The unique configuration with destroyed waveguide supplies an excellent platform for achieving full color random lasing through the cascade pumping process. Random lasing with tunable wavelengths spanning the entire visible range is achieved via side-pumping schemes. The eight acceptor RLs can be simultaneously pumped to obtain chromaticity-programmable random lasing, showcasing a Commission Internationale de l'Eclairage (CIE) color map with 155% more perceptible colors than the standard red-green-blue space. This opens the possibilities for programmable RLs with potential applications in biological imaging and smart sensing.

Charge pumping triboelectric nanogenerator with dust clearance and elastic support for wind energy harvesting

Triboelectric nanogenerator (TENG) as an energy harvester faces the challenges of low surface charge density, dust generation in friction and soft contact within dielectrics. Accordingly, a charge pumping triboelectric nanogenerator with a tubular-plate coupled structure is proposed to address the above challenges and is used to harvest wind energy. It mainly consists of a top tubular TENG and a bottom plate TENG, synchronously driven by an unidirectionally open-closed fan blade through a shared shaft. The unidirectionally open-closed fan blades produce an eccentric torque with the different open-closed states, which is used as the impetus for the unidirectional rotation of the fan structure and the rotor of TENG. Charge pumping technology is applied in top TENG to enhance surface charge density and outputting electricity in way of noncontact electrostatic induction. The COMSOL software is applied to obtain the distribution of electric field and potential during the relative motion of two tubular electrodes. Lint blades and steel sheets are utilized in bottom TENG for the dust clearance and the elastic support, respectively. Consequently, the voltage is increased by 15.5 times and the current about 3.0 times with the charge pumping strategy. The dust clearance and elastic support can improve the output current. The total output voltage is up to 2.8 kV and the current is 103.0 μA at 200 rpm, generating a peak power of 184.9 mW and an average power of 6.4 mW. A buck circuit is used in the output circuit to lower and stabilize the output voltage for the electronics. The output electricity can support the work of a thermo-hygrometer, two linear lamps (10 W), two circular LED lamps (18 W), and light 417 big LEDs with a diameter of 10 mm, serving as a continuous energy source in wilds.

A Coupled Human and Natural Systems (CHANS) framework integrated with reinforcement learning for urban flood mitigation

To address the challenge of escalating urban flood risk and the deficiency in effective flood emergency management, this study introduces a novel Coupled Human and Natural Systems (CHANS) modelling framework that employs hierarchical reinforcement learning to optimise mobile pump scheduling and placement for urban flood risk mitigation. The CHANS framework integrates hydrodynamic and agent-based models within a multi-GPU computing environment for high-resolution, real-time flood inundation modelling and risk assessment to enrich Reinforcement Learning (RL) training. In the application to Ninh Kieu District in Can Tho City, Vietnam, the new RL-enabled modelling framework is used to evaluate optimal mobile pumping strategies for concurrent pluvial flooding and post-flooding events against the traditional deployment approaches. Results demonstrate that RL-based strategies can significantly enhance flood risk reduction, outperforming traditional methods by achieving 2× and 4× improvements in the concurrent and post-flooding periods/events, respectively. Incorporating human factors and adapting to local conditions, the RL agent provides valuable insights into mobile pump scheduling and deployment strategies. Sensitivity analysis confirms the robustness of the CHANS modelling framework and underscores the role of RL in optimising mobile pump scheduling and placement where traditional rule-based strategies are challenging.

Numerical Analysis of Flood Invasion Path and Mass Flow Rate in Subway Stations under Heavy Rainfall Conditions

The occurrence of extreme weather, such as heavy rainfall and sudden increases in precipitation, has led to a notable rise in the frequency of flooding in subway stations. By conducting numerical simulations of flood disasters in subway stations under heavy rainfall conditions and gaining insights into the patterns of flood invasion inside the stations, it is possible to develop practical and feasible drainage designs for the stations. This paper employs the computational fluid dynamics (CFD) method, utilising the volume of fluid function (VOF) method and the renormalization k-ε group model within the vortex viscosity model. The complete process of flood invasion into subway stations with varying water levels (1500 mm, 2000 mm, and 2450 mm) is modelled, and the distribution of floods at different times under varying operational conditions is analysed to identify the evolutionary patterns of station flood history. The simulation calculations yielded the mass flow rate time history curve at the tunnel entrance and exit, which was then subjected to an analysis of its development trend over time. The total accumulated water in the subway station is calculated by integrating the difference in mass flow rate between the entrance and the tunnel exit, using the mass flow rate curve. In conclusion, the paper proposes drainage measures that provide valuable insights into pumping strategies when floodwaters infiltrate subway stations. The results indicate that the speed of flood spreading in subway stations increases with higher groundwater levels, and that the mass flow rate of floodwater entering the tunnels increases over time, eventually reaching a stable state. It was observed that, at certain times, the mass flow rate of floodwater into the tunnels exhibited a linear relationship with time.

Rising damp in heritage sites under urban expansion: A comprehensive case study of the Jinsha Earthen Site

Rising damp poses a significant threat to cultural heritage, yet its dynamics within actual heritage sites remain inadequately understood, particularly regarding its evolution and the impact of urbanization. The Jinsha Site, an earthen site from the Shang periods, is primarily composed of silt, with a layer of sand beneath and pebbles at the bottom, making it susceptible to rising damp. This study investigates the Jinsha Site as a case, monitoring soil water content and electrical conductivity, tracking changes in groundwater, precipitation, and river water levels, and investigating the relationship between urbanization and rising damp. The study aims to understand the process, causes, and influencing factors of rising damp and evaluate previous preservation strategies. The findings indicate that groundwater level in the sand layer trigger dampness, whereas the pebble layer exhibits dryness. Urban construction from 2006 to 2013 and 2014–2017 caused fluctuating groundwater levels, leading to repeated transitions between dryness and dampness at the site. Rainfall and river levels have negligible effect; even rainfall exceeding 100 mm (frequency <0.0056) only raises groundwater levels by approximately 1 m and increases water content by less than 2 % for a brief duration, typically less than half a month. The 2022 groundwater pumping strategy effectively maintained levels beneath the pebble layer (506 m), decreasing moisture by 12.71 % and conductivity by 0.27 dS/m. This study reflects on previous protection effortsand offers evidence-based strategies for heritage conservation amidst urban expansion.

High-performance coaxial reversal rotational triboelectric nanogenerator based on charge pumping strategy driving tip high voltage breakdown

Triboelectric nanogenerator (TENG) serves as an effective method for harvesting mechanical energy from the surrounding environment. Nonetheless, its practical application is hindered by issues such as inadequate charge density and wear of friction surface materials. Here, a high-performance self-supplementing coaxial inverse triboelectric nanogenerator (HSCI-TENG) based on charge pumping supplementary strategy is presented, which operates in non-contact mode and increases surface charge density with almost no friction loss. The coaxial reversal design facilitates dual-speed rotation, resulting in a significant enhancement of the output current. Furthermore, an innovative approach was employed by affixing four layers of 0.06 mm thick PET film to the storage electrode, thereby augmenting the threshold of electrode charge storage and effectively mitigating the risk of electrode breakdown. At a rotation speed of 300 rpm, the peak-to-peak voltage, peak-to-peak current, and charge transfer of HSCI-TENG are 3340 V, 360 μA and 0.97 μC, respectively. Excellent stability is demonstrated through 10000 cycle tests on the output of HSCI-TENG. In particular, the maximum output power is 770 mW at a load resistance of 8×106 Ω. The high-performance HSCI-TENG has been proven to be a stable energy source driving high voltage breakdown sensor system. The tip high voltage breakdown exhibits high frequency and continuity, with 14 breakdowns occurring within 10 seconds. Besides, HSCI-TENG has potential to serve as an energy source for high-pressure sterilization, high-pressure dust removal, and water electrolysis systems.

OpSAVE: Eviction Based Scheme for Efficient Optical Network-on-Chip

For on-chip networks, nanophotonics has been considered a strong alternative owing to its high speed (due to low latency) and high bandwidth (due to wavelength division multiplexing). However, the major hurdle in the adoption of nanophotonic-based on-chip networks is their high static power consumption. Various proposals are there in the literature which try to reduce the static power consumption either by modulating the laser or by allowing the on-chip stations to share the photonic channels. In this paper, we propose OpSAVE— an optical NoC that combines the above two strategies to effectively reduce static power consumption. It proposes a superior prediction mechanism based on the eviction details from the private caches. It explains how shared channels can be used to dynamically balance the load and at the same time handle mispredictions. It allows the optical stations to share both the power and the available bandwidth to increase their utilization. Moreover, OpSAVE proposes to use a double pumping strategy to improve the system performance. We compared our scheme with the state-of-the-art proposals in this domain and the results show that our scheme consumes 4.4X less optical power and at the same time improves the performance by nearly 28%. In the evaluation, we have considered the multicore benchmarks from the Splash and Parsec benchmark suites.

Self‐Boosting Energy Generation via Triboelectric Nanogenerator–Capacitor Coupling

AbstractWith the development of wearable and wireless electronic devices, the triboelectric nanogenerator (TENG) is attracting interest as a candidate for portable power. Many studies are conducted to increase the surface charge density of the TENG, such as external charge pumping or external electron excitation strategies. However, there are limitations in that another additional external energy source is required. Here, a TENG–capacitor (TC) coupling system that can maximize energy generation and storage efficiency within a limited volume is proposed. Density functional theory calculations indicate that the electric field induced on capacitor increases the fermi energy of positive triboelectric material, resulting in more charge transfer between two triboelectric materials. TC coupling system enhances TENG output performance and the capacitor charging rate in a virtuous cycle. This study provides new insights into TENG structural design and an important guideline for the use of TENG as a portable power source for wearable and wireless applications.

Assessing the feasibility of sprinkler irrigation schemes and their adaptation to future climate change in groundwater over-exploitation regions

Promoting appropriate water-saving irrigation is an important pathway to alleviate groundwater overexploitation in irrigated agriculture. Whether an alternative irrigation method is feasible relies on quantitative assessments of its impacts on crop yield and hydrological cycle, especially in the groundwater overdraft area that faces a dilemma between water scarcity and food security. Using a groundwater-module-improved SWAT (Soil & Water Assessment Tool) model, five GCMs (General Circulation Models) projections of CMIP6 (Coupled Model Intercomparison Project 6), and a linear programming algorithm, sprinkler irrigation was simulated, evaluated, and optimized in a representative global groundwater mining location, the piedmont plain of the North China Plain. During the historical period (1993–2012), the results showed that, in general, sprinkler irrigation had advantages in benefiting crop transpiration of winter wheat and reducing percolation, hence improving water use efficiency with reference to traditional surface irrigation. Specifically, compared to traditional surface irrigation schemes, winter wheat yields increased by 12%− 14% with a 225 mm irrigation quota; they were stable with a 150 mm irrigation quota; but they decreased by 4% with a 75 mm irrigation quota. The shallow groundwater tables would decline at an average rate of 1.29 m/yr, 0.83 m/yr, and 0.35 m/yr, respectively, under sprinkler irrigation with 225 mm, 150 mm, and 75 mm irrigation quotas. Future climate changes (increased precipitation, air temperatures, and CO2 concentration) would bring effects of improving wheat yield by 6%− 7% and increasing groundwater vertical recharge by 58%− 122% in 2030–2049. The variations of predicted future shallow groundwater tables were − 0.37 m/yr, 0.01 m/yr, and 0.40 m/yr with the 225 mm, 150 mm, and 75 mm irrigation quotas, respectively, in the SSP2–4.5 scenario; and the corresponding results were − 0.45 m/yr, − 0.05 m/yr, and 0.34 m/yr in the SSP5–8.5 scenario. The optimization results showed that sprinkler irrigation could be implemented in approximately 50% of the study area to achieve shallow groundwater equilibrium and stable wheat production simultaneously in the near future. And the dominant sprinkler irrigation schedule after optimization was found to be scheme S3 (irrigation frequency for wheat was 5 times) with a limited irrigation quota of 150 mm. This study provides detailed data for planning sprinkler water-saving irrigation regimes and groundwater pumping strategies in China’s breadbasket, as well as a reference for global irrigated agriculture with over-drafted aquifers to balance groundwater conservation and grain production.

Directed Dual Charge Pumping Tunes the d-Orbital Configuration of Pt Cluster Boosting Hydrogen Evolution Kinetic.

Achieving high catalytic activity with a minimum amount of platinum (Pt) is crucial for accelerating the cathodic hydrogen evolution reaction (HER) in proton exchange membrane (PEM) water electrolysis, yet it remains a significant challenge. Herein, a directed dual-charge pumping strategy to tune the d-orbital electronic distribution of Pt nanoclusters for efficient HER catalysis is proposed. Theoretical analysis reveals that the ligand effect and electronic metal-support interactions (EMSI) create an effective directional electron transfer channel for the d-orbital electrons of Pt, which in turn optimizes the binding strength to H*, thereby significantly enhancing HER efficiency of the Pt site. Experimentally, this directed dual-charge pumping strategy is validated by elaborating Sb-doped SnO2 (ATO) supported Fe-doped PtSn heterostructure catalysts (Fe-PtSn/ATO). The synthesized 3%Fe-PtSn/ATO catalysts exhibit lower overpotential (requiring only 10.5mV to reach a current density of 10mAcm- 2), higher mass activity (28.6 times higher than commercial 20wt.% Pt/C), and stability in the HER process in acidic media. This innovative strategy presents a promising pathway for the development of highly efficient HER catalysts with low Pt loading.

High-power 970 nm semiconductor disk laser.

Semiconductor disk lasers (SDLs) have emerged at the frontier of laser technologies. Here, the chip design, packaging process, resonator, pumping strategy, etc. are optimized for the performance improvement of a 970 nm SDL. After optimization, a power of 70.3 W is attained under continuous wave (CW) operation, and the corresponding thermal resistance is around 0.49 K/W. The laser is highly efficient with a maximum slope efficiency of 58.2% and the pump threshold is only around 1.83 kW/cm2. Furthermore, the emission performances under quasi-continuous wave (QCW) pumping are also explored. Setting the duty cycle to about 11%, the chips can output a peak power of 138 W without thermal rollover, and the single pulse energy can reach about 13.6 mJ. As far as we know, they are the best results in terms of power/energy in this wavelength SDL. These explorations may help to understand the thermal characteristics in high-power SDLs and may also be regarded as an extension and enrichment of the earlier works on this topic.

Optimizing groundwater pumping in small island groundwater lenses: An analytical approach

For residents living on small islands, groundwater serves as their primary source of freshwater, which exists in the form of a freshwater lens floating above denser seawater. Previous research on optimizing pumping strategies in freshwater lenses focused on pumping from fixed wells using numerical models, and optimal well locations have not been explored. In this study, we analyze pumping optimization for both fixed well cases and moving well cases in a rectangular island using an analytical approach. This approach allows for a clear understanding of the relationship between hydrogeological parameters and optimization results. For fixed well cases, we provide an analytical solution for the critical pumping rate of each well. For moving well cases, Bayesian optimization is employed to efficiently search the extensive space of possible well locations and identify the critical pumping rate. Our results reveal that the well location has a substantial impact on the critical pumping rate in the fixed well cases, indicating that investigating the optimization of well placement is essential. In the discussion of the moving well cases, the maximum total pumping rate of a pumping well network is independent of hydraulic conductivity, and the critical pumping percentage relative to total recharge is independent of both hydraulic conductivity and recharge. The distribution of optimized well locations for islands with a fixed aspect ratio but different sizes follows the same pattern. In the moving well cases, different solutions can achieve the same maximum pumping rate, especially when multiple wells are involved. In addition, our approach is applicable to scenarios where new wells are added to an existing well system. Our solutions and findings significantly contribute to a deeper understanding of the hydraulic performance of pumping activities from freshwater lenses and offer valuable insights for developing more sustainable and robust groundwater management strategies in small islands.

The hydrodynamics and kinematics of the appendicularian tail underpin peristaltic pumping.

Planktonic organisms feed while suspended in water using various hydrodynamic pumping strategies. Appendicularians are a unique group of plankton that use their tail to pump water over mucous mesh filters to concentrate food particles. As ubiquitous and often abundant members of planktonic ecosystems, they play a major role in oceanic food webs. Yet, we lack a complete understanding of the fluid flow that underpins their filtration. Using high-speed, high-resolution video and micro particle image velocimetry, we describe the kinematics and hydrodynamics of the tail in Oikopleura dioica in filtering and free-swimming postures. We show that sinusoidal waves of the tail generate peristaltic pumping within the tail chamber with fluid moving parallel to the tail when filtering. We find that the tail contacts attachment points along the tail chamber during each beat cycle, serving to seal the tail chamber and drive pumping. When we tested how the pump performs across environmentally relevant temperatures, we found that the amplitude of the tail was invariant but tail beat frequency increased threefold across three temperature treatments (5°C, 15°C and 25°C). Investigation into this unique pumping mechanism gives insight into the ecological success of appendicularians and provides inspiration for novel pump designs.

Comparison of Two Pumping Strategies to Improve Exclusive Breastfeeding at Discharge in Mothers of VLBW Infants with Low Milk Output - A Pilot Randomized Controlled Trial.

To compare the effect of two strategies of breast pumping-power pumping (PP) vs. routine pumping (RP) over one week in mothers of very low birth weight (VLBW) infants with low milk output to improve breastfeeding rates at discharge. Mothers with low milk output, defined as inability to express sufficient breastmilk to meet the feeding requirements of their infant on or after post-natal day 14, were randomized to receive power pumping vs. routine pumping - once daily for 7 d coupled with routine lactation support and hand expression 3 hourly in both groups. The primary outcome was exclusive breastfeeding at discharge. There was no difference in the two pumping strategies with respect to exclusive breastfeeding rates [61.1% in PP vs. 50% in RP group; (p = 0.477, RR 1.2; 95%CI 0.76 to 2.17)]. Median milk volume pumped in the individual power pumping session on 7th day of intervention was significantly higher than that in the individual routine pumping session on the 7th day (50 mL vs. 27 mL, p = 0.014). The cumulative median milk volume expressed per individual pumping session over the 7 sessions of power pumping was also higher than that with routine pumping (305 mL vs. 213 mL, p = 0.054). In this pilot trial, expressed milk volume was significantly higher after each individual power pumping session compared to routine pumping. However, the exclusive breastfeeding rates at discharge were similar in the two groups.

Investigating the Impact of Seawater Intrusion on the Operation Cost of Groundwater Supply in Island Aquifers

AbstractManaging fragile island freshwater resources requires identifying pumping strategies that trade off the financial cost of groundwater supply against controlling the seawater intrusion (SWI) associated with aquifer pumping. In this work, these tradeoffs are investigated through a sensitivity analysis conducted in the context of an optimization formulation of the groundwater management problem, which aims at minimizing the groundwater supply operation cost associated with groundwater pumping and desalination treatment, subject to constraints on SWI control, as quantified by the water table drawdown over the well (∆s), the reduction in freshwater volume (∆FV) in the aquifer, or the salt mass increase (∆SM) in the aquifer. This study focuses on a simplified two‐dimensional model of the San Salvador Island aquifer (Bahamas). Pumping strategies are characterized by the distance of the pumping system from the shoreline (WL), the abstraction screen depth (D) and overall pumping rate (Q), constituting the decision variables of the optimization problem. We investigate the impacts of pumping strategies on the operation cost, ∆s, ∆FV and ∆SM. Findings indicate increasing D or decreasing WL reduces ∆s, ∆FV and ∆SM, thus preserving the aquifer hydrogeologic stability, but also leads to extracting saltier groundwater, thus increasing the water treatment requirements, which have a strong impact on the overall groundwater supply cost. From a financial perspective, groundwater abstraction near the island center and at shallow depths seems the most convenient strategy. However, the analysis of the optimization constraints reveals that strategies where the pumping system approaches the island center tend to cause more severe SWI, highlighting the need to trade off groundwater supply cost against SWI control.

Importance of Aquitard Response Time for Groundwater Management in Multi-Aquifer Systems Subject to Land Subsidence

Groundwater management models have been widely applied to obtain optimal pumping strategies for land subsidence control, but most of them do not explicitly incorporate land subsidence variables (such as cumulative settlement and land subsidence rates) within the model constraints and neglect the transient effect due to aquitard storage. Here, three operating scenarios of a hypothetical multi-aquifer system, which include a highly compressible aquitard, were implemented with the aim of evaluating land subsidence and identifying management schemes with the support of an optimization model for groundwater management. In a 50-year management period, maximizing pumping while restricting drawdown to 10 m after year 25 stabilizes groundwater levels within the aquifer, but land subsidence continues to reach 4.8 m at year 50. The effect of reducing pumping rates and how early in the management period this is implemented is also analyzed. Restricting the pumping rate as early as year 6 leads to reduced land subsidence at year 50 by 17%. If pumping reduction is delayed, larger land subsidence rates occurred in the system (7.9, 8.3 and 9.6 cm/year in the tested cases); however, if the total settlement is evaluated as a proportion of the thickness of the aquitard, values of the order of 10% are presented. Our results highlight the importance of timely decisions for groundwater management based on the response time of the aquitards in multi-aquifer systems.

On the correlation between proppant addition strategy and distribution

The proppant pumping schedule is critical in hydrofracking because it affects both fluid flow and proppant transport. In the study reported here, a validated CFD-DEM model was employed to study the impact of proppant pumping strategy on proppant transport in a rough rock fracture. Three injection sequences of multi-sized proppants were applied while varying other pumping parameters including injection velocity, the size of large proppants, and the concentration of large proppants. Both vertically and horizontally sheared rough, joint rough, and smooth fractures were adopted to enable a better understanding of the impact caused by fracture geometry. The results reveal that the variation in proppant distribution caused by adjusting the pumping sequence or a single pumping parameter is not absolute. Rather than pumping parameters, the final proppant distribution is governed directly by two competing effects caused by the alteration of proppant bridging effect. It was also found that the proppant volume retained in fractures is under-estimated if the CFD mesh size is too small to reach three times the particle size. The lateral conveyance of proppant could be enhanced by considering the Saffman lift force in CFD-DEM modeling. The results of this study shed light on proppant transport in hydraulic fractures under various addition strategies, which will assist the optimization of fracturing treatments in unconventional reservoirs.

A piezo-triboelectric hybrid nanogenerator based on charge pumping strategy

The rapid progress in the Internet of Things speeds up the construction of wireless sensor network. The hybrid nanogenerator combining the triboelectric nanogenerator (TENG) and piezoelectric nanogenerator (PENG) is expected to solve the problem of the continuous power supply of sensor nodes. However, the current hybrid nanogenerator suffers from low power integration efficiency and complex impedance matching circuits. This paper proposes a piezo-triboelectric nanogenerator (PE-TENG) that integrates TENG and PENG via charge pumping strategy. The excitation-PENG working in resonant mode rapidly accumulates charge of the synchronously rotating triboelectric-layer, which increases the surface charge density of TENG. This strategy achieves direct coupling of the outputs from two different types of nanogenerators, significantly improves the power integration efficiency and reduces the establishing time of PE-TENG to the millisecond level (50 ms). The peak power is increased by 222.5% and the average power is boosted by 706.6% compared with the traditional optimal output. A maximum peak power of 5.9 mW and an average power of 2.1 mW are achieved at a low drive frequency of 2.5 Hz. The PE-TENG can successfully power some electronic devices. This study provides a useful reference for hybrid nanogenerators.

Industrial processes and the smart grid: overcoming the variability of renewables by using built-in process storage and intelligent control strategies

Manufacturers are facing pressure to reduce electricity costs. Onsite renewable energy generation may be a solution, but its high capital cost and intermittent power generation limit its use. Grid-responsive smart manufacturing could effectively incorporate renewables in industrial processes. This study integrates grid-responsive smart manufacturing with renewables on an industrial plant scale and demonstrates both a favourable economic and environmental outcome. A user-friendly decision-aid model for energy management is provided to manufacturers. A case study shows how solar panels, industrial batteries, smart pumping strategies, and various combinations of those elements can save on electricity costs. Dynamic simulation results demonstrate that grid-responsive smart manufacturing can effectively lower peak demand. The economic results show that grid-responsive smart manufacturing and renewables synergistically optimise cost reductions. The solar coupled with smart pumping scenario shows annual cost savings of $755,200, accounting for 4.6% of the total electricity cost. Smart pumping alone saves $371,900 annually with a 0.7-year payback period, demonstrating how the manufacturing sector can utilise its own processes in load shifting. This study supports that incorporating grid-responsive smart manufacturing with renewables can effectively reduce electricity costs and emissions for industry. Abbreviations: e: Equivalent; GHG: Greenhouse gas; PBP: Payback period; PV: Photovoltaics; SP: Setpoint; VFD: Variable speed drives