Harvesting Structures Research Articles

Bioinspired Moisture‐Driven Soft Robotic Actuator

Multifunctional materials in nature, utilizing atmospheric water content, offer solutions to challenges in soft‐actuating materials research. The leaf of Arundo donax, an invasive plant, showcases exceptional properties: structural integrity, passive actuation, tunability, load‐bearing capacity, longevity, and an integrated battery‐free fluid generation and distribution mechanism. These functions coexist within a thin (≈130 μm) and lightweight structure with simple compositions. The study investigates material composition, passive fluid transport, water harvesting structures, and mechanical properties, revealing unexpected correlations between surface and internal structures. Additionally, tunable actuation, suitable for origami‐based mechanisms, is explored. Testing an energy‐free, moisture‐triggered soft robotic gripper, its ability to lift over 50 times its weight while maintaining sufficient softness for delicate tasks is demonstrated. This unit‐wise structure‐based actuation offers promise for soft robotics, with favorable fabrication possibilities and motion manipulation.

Determining food intake, the requirement, and weighing the relative risk between food secure and insecure households in rural areas of Ethiopia: The case of West Hararghe zone

The severity of food insecurity in Ethiopia is among the worst globally, with record-breaking food assistance needs by various factors. This study tries to uncover various aspects of food security related to food availability, food access, food utilization and food stability dimensions of food security. The study was executed in the west Hararghe zone of the Oromia region of Ethiopia. Its main objective was to determine the food security status of households, with specific objectives aiming at computing individual daily kilo calorie intake, determining the average food requirement, comparing the relative risk between food secure and insecure households and identifying factors that affect household food security status. A multi-stage sampling procedure, involving the purposive selection of; the Zone and Woreda, and a simple random selection of households, to draw the required number of representative sample respondents, was adopted. Hence, from 4163 total households, 134 were selected for collecting primary data. Data were analyzed using descriptive statistics, relative risk analysis using Cohorts and independent tests using ANOVA. Food security status was measured using the Household Food Balance Model (HFBM). Using this model, the study obtained 1973 kilo calories per individual per day intake and 2108 kilo calorie as their requirement, which indicated households were energy deficient by 135 kilo calorie with 2-sided-value < 0.1 critical level (t= -1.747, df =133 & sig2-sided. 0.083). Independent test results showed that farm income (at p-value < 0.1), gross product (at p-value < 0.05), age of household head (at p-value < 0.1), years of owning land (at p < 0.1) and family size (at p-value < 0.1) contributed significantly to food security status. Cross-tabulation showed a linear relationship between food security and higher education level (at p-value < 0.05), which urges a concern in improving farming societies’ literacy to the desired level. In the study areas, about 91.8% of the population produces crops depending on the seasonal rainfall and their daily kilo calorie consumed depends on it; this is statistically correlated with the food insecurity problem at p-value < 0.1 critical level (lambada = 1.75 & sig. = 0.08). Therefore, to tackle the food insecurity problem, alternative method of crop production should be devised such as the establishment of irrigation schemes, water harvesting structures, and water conservation practices, among others. Key words: food security, calorie requirement, food availability, relative risk

A Kelp Inspired High‐Power Density Triboelectric Nanogenerator with Stacking Structure for Multiple Directional Ocean Wave Energy Harvesting

AbstractOcean wave energy is one of the most promising green energies in the wild. However, it is still challenging to effectively collect wave energy due to its randomness and irregularity. In this work, a kelp inspired high‐power density triboelectric nanogenerator (K‐TENG) is presented for harvesting wave energy with characteristics in multiple directions. The proposed K‐TENG consists of a series of stacked leaf‐like units. The influence of configuration parameters, including pellet diameters, pellet numbers, unit sizes, oscillation frequency, swing amplitude, and wave directions on output performances of leaf‐like units, are extensively investigated. Experimental data indicates that a single leaf‐like unit can achieve a maximum output voltage of 623.14 V as well as a maximum current of 1.48 µA and realize energy harvesting from different wave directions. A K‐TENG composed of 15 leaf‐like units demonstrates a high‐power density of 18.77 W m−3 at a wave frequency of 2.5 Hz, which successfully powers a digital watch and 414 light‐emitting diodes (LEDs). This work is hoped to provide a simple and reliable route to effectively harvest ocean wave energy.

Assessment of Constraints and Suggestion Insights from Beneficiaries of Centrally Sponsored Agricultural Schemes: A study of PKVY, PMKSY and SHC in Vidarbha Region of Maharashtra, India

The present study focused on assessing the constraints faced by the beneficiaries of centrally sponsored agricultural schemes namely Paramparagat Krishi Vikas Yojana (PKVY), Pradhan Mantri Krishi Sinchayee Yojana (PMKSY), and the Soil Health Card Scheme (SHC) and invited suggestions from them to overcome the constraints. For the proposed study, 60 beneficiary farmers were selected from Amravati districts and 60 beneficiary farmers were selected from Buldhana districts in Vidarbha region of Maharashtra for each scheme. Thus, for the three schemes, a total of 360 beneficiary farmers were selected. In the case of PKVY beneficiaries, the major constraints faced were lack of proper marketing channel for organic produce, lack of sustainability in the reduction of cost of organic cultivation and reduced productivity of organic farm produce even after conversion period. Whereas, in the case of constraint faced by PMKSY beneficiaries, the first constraint faced by the beneficiary was longer time for getting the subsidy credited, followed by lack of increase in the sources of irrigation and load shedding of electricity. In the case SHC beneficiaries, the major constraint faced were long time gap between soil sample collection and issuing SHC, difficulty to comprehend the information and follow the recommendations provided in SHC and lack of effective training and demonstrations provided to farmers about soil health. In the case of PKVY beneficiaries, majority of them (74.17%) gave the suggestion for establishment of proper marketing channel for organic produce, followed by 34.17 per cent of them suggested the strengthening of farmer groups and developing them into Farmer Producer Organizations (FPOs). Whereas in the case of PMKSY beneficiaries, 84.17 per cent of them suggested to ensure timely crediting of subsidies, followed by expansion of irrigation infrastructure through the construction of water harvesting structures such as check dams, farm ponds, tanks and bore wells (59.16%). In the case of SHC beneficiaries, majority of them (85.83%) gave the suggestion to speed up the process of issuing Soil Health Cards and 71.66 per cent suggested for training programs and field level demonstrations focused on soil health and the practical application of SHC recommendations to improve farmers' knowledge and skills.

Efficient Fog-Harvesting Origami Fan.

Fog harvesting represents a promising strategy to address the global freshwater shortage. To enhance the water collection efficiency, diverse geometric structures that can effectively drive water droplet movement are essential. Inspired by the Livistona chinensis leaf, which naturally facilitates directional droplet motion through its unique gradually varying V-groove structure, we have developed a novel origami fan structure for fog harvesting through theoretical analysis. A key feature is that we can modulate the speed of droplet transport by adjusting the opening angle of the V-shaped grooves positioned at the outer circumference. Interestingly, the water collection efficiency exhibits a linear correlation with the opening angle. The highest efficiency of the origami fan can reach 5.75 times that of the control group calculated by the projected area and 3.76 times that of the control group calculated by the real area, showcasing its significant potential for enhancing water collection from fog. The simulations demonstrate that the hollow structure enhances the condensation rate of droplets, the geometric gradient of the gradual-variation V-groove drives the condensed droplets to move rapidly on the surface, and the Janus membrane permits the aggregated droplets to transit to the fan's rear side. The synergistic action of these three components ensures a clean surface for the subsequent water-collecting cycle, contributing to the high fog-harvesting efficiency. Given its simple fabrication and superior water transfer efficiency, the origami fan holds substantial promise for widespread application in the field of droplet manipulation.

Identification of groundwater potential zone and Water harvesting Structures using remote sensing and GIS technique in Chilapura Watershed, Davangere district, Karnataka state.

Identification of groundwater potential zone and Water harvesting Structures using remote sensing and GIS technique in Chilapura Watershed, Davangere district, Karnataka state.

Design and experimentation of width tapered meandered array structure for low frequency broadband vibration energy harvesting

A novel 6DoF Tapered beam energy harvester, capable of operating across a broad and low frequency range, is proposed in this work. The hybrid structure incorporates regular beam array and zig-zag sections, enhancing deformation and bending. Width tapering with constant thickness optimizes the structural performance and energy harvesting capabilities of the beam. Tapering ensures even strain distribution, reducing the risk of structural failure. The proposed structure demonstrates wide band characteristics at low frequencies, delivering higher power output compared to an array of cantilevers for a given area. FEM analysis is conducted to optimize proof mass, aiming for closely spaced resonance frequencies and high-power output. Experimental validation on a prototype confirms the accuracy of the frequency response predicted by the models. Under harmonic base excitation of 0.4 g, the harvester yields an average DC power of 2497 μW, accounting for signal conditioning losses, within the frequency range of 9–20 Hz. The suggested structure offers excellent design flexibility, allowing adjustment of resonant frequencies by varying the number of beams, the slope and the proof mass of individual beams. The geometry of the proposed structure provides versatility, mechanical resilience, uniform strain distribution make it suitable for developing MEMS energy harvesters.

Nonlinear effect on stable state and snap-through bistability of square composite laminate

Bistable structures with the elastic instability caused by buckling are confirmed to perform significantly in micro-electromechanical systems, metamaterials, energy harvester, vibration isolation and morphing structures. The target of this paper is to explore the dynamic responses of cross-ply bistable composite laminate, focusing on the nonlinear effect of the single- and double-well vibration. Both theoretical and finite element (FE) methods are employed to simulate the nonlinear vibration and dynamic snap-through of bistable composite laminate under the foundation excitation at the center. In the theoretical model, the governing equations are established via Lagrange's equation based on the first-order shear deformation theory, von Karman nonlinear strain-displacement relation and Rayleigh-Ritz method. The fourth-order Runge-Kutta method is adopted to solve the governing equations, and the numerical results are validated by FE model. Subsequently, the details of the dynamic responses are analyzed to identify the nonlinear effects in the form of bifurcation diagram, phase portrait, time history, Poincare maps and amplitude spectrum. The dynamic responses are examined for a series of excitation parameters in both time and frequency domain. Through fixed frequency and frequency sweep tests, the nonlinear phenomenon of the single- and double-well vibrations are analyzed including superharmonic resonance, stiffness softening, hysteresis phenomenon, various periodic and chaotic vibration. The diverse responses to external inputs contribute significantly to efficiently predicting mechanical behaviors in real-world conditions, thereby offering indispensable theoretical support for structural design applications.

Optimizing radiation capture in machine-harvested cotton: A functional-structural plant modelling approach to chemical vs. manual topping strategies

Topping and planting density are key agronomic management practices to optimize cotton plant structure for machine harvesting and light capture. However, modelling the effects of these practices on canopy light utilization in the field, in order to improve cotton management, remains challenging. Functional-structural plant modelling is a computational approach to explore the effects of agronomic practices on shaping plant architecture and thus light interception. This study, for the first time, utilizes the CottonXL model to quantify the significant impact of chemical topping compared to manual topping on radiation interception on machine-harvested cotton in China at different planting densities, providing new management strategies for cotton production. A more compact plant structure is shaped by chemical topping through inhibiting leaf expansion and shortening internodes of both the main stem and fruiting branches, thereby allowing more PAR interception by middle and lower leaves. Simulation results showed that the total PAR intercepted by the canopy over entire growth season was increased by 11.3 % under chemical topping compared to manual topping. This positive effect became even more pronounced with increasing plant density. These results indicate that chemical topping could be beneficial for optimizing canopy structure, enhancing light interception and lint yield, especially at higher plant densities. The results illustrate the importance of shaping plant structure for improving radiation resource capture and exemplify the potential of optimizing topping strategy and plant density to enhance crop performance. They also demonstrate the utility of a functional-structural plant model for guiding crop management.

Modern Methods and Solutions for Water Resources Management in the Wadi-Watir Region (Egypt)

The main problem of water resources in Egypt is the increasing demand and decreasing supply, especially after the construction of the Ethiopian Renaissance Great Dam. One of the best solutions is the use of unusual alternative management techniques, including as a major one, rainwater harvesting and distribution. This paper examines the use of unconventional approaches to water management in arid regions based on rainfall accumulation. Using Geographic Information Systems (GIS) and hydrological modelling, the suitability of the Wadi-Watir catchment (Egypt) for rainwater storage was assessed and optimal locations for the construction of storage structures were identified. The results of the study showed that 19% (666 km2) of the study area is highly suitable for the aims and objectives; 16% (573 km2) of the catchment area has limited realisability. Twelve sites were found to be suitable for the construction of storage dams. Fourteen sites are identified as optimal for the placement of percolation (filtration) reservoirs along watercourses. The area considered ideal for above-ground percolation (filtration) tanks is 25.9 km2. The optimum area for farm ponds is 1.34 km2. As a result, the construction of water storage structures is proposed to improve water management in the Wadi-Watir region. The implementation of the rainwater harvesting structures (SRF) was divided into three phases depending on the severity of the flash flood hazard. The first, second and third phases can meet 62.24% (34.24 mil m3) of the water demand. This approach is a new and modern solution to the problem of water scarcity under socio-economic and environmental pressures while achieving the goals of sustainable development in Egypt. The article is based on the dissertation research of Mohamed Mostafa Ezzeldin Abdelrahim (MGSU, dissertation council № 24.2.339.07, March 2024).

Addressing water security challenges through groundwater recharge for revival of Kanari River using AHP and geospatial techniques

Artificial recharge of groundwater has been recognized as a promising option for sustaining groundwater supplies and ensure water security for the ever rising population. With the aid of geospatial and multi-criteria decision analysis methodologies, the current study's scope aids in evaluating groundwater potential zones and locating suitable zones and sites for groundwater recharge for the revival of the Kanari River. A pragmatic methodology was suggested in this study for implementing water harvesting structures for river revival and estimation of water demand, pumping, and recharge. The geometric mean and the normalized weight for individual features were specified using the AHP in a GIS environment. All the different features/datasets were overlaid, and possible groundwater zones were revealed using AHP. Integrated maps were used to identify the groundwater recharge zone and locations for establishing artificial recharge structures within the Kanari River system. Ultimately, the domestic water demand, agriculture water use, pumping, and livestock water demand were estimated for water budgeting, and based on this data, the water availability was calculated. Based on the study results, the water demand of the Kanari River watershed was estimated to be 732 MCM. Taking into consideration the supply and demand scenarios, the pumping overdraft of the Kanari River watershed was found to be 423 MCM, and the proposed additional recharge through the planned conservation structures was estimated to be 859 MCM. So, even if pumping overdraft is considered, this additional groundwater recharge can fulfill the local demand, help maintain the river flow, and ensure water availability and security in the region.

Impacts of Climate Change on Streamflow on Dawa Sub-watershed, Genale-Dawa River Basin, Southern Ethiopia

<i>Climate change is statistical variations over an extended period in the features of the climate system, such as variations in global temperatures and precipitation, caused by human and natural sources.</i> In this study aimed to measure and examine how streamflow in the Dawa sub-basin, Genale Dawa River basin was affected by climate change. It used the average of five regional climate models from the Coordinated Regional Climate Downscaling Experiment (CORDEX) Africa, under two different scenarios of Representative Concentration Pathways: RCP4.5 and RCP8.5. The baseline scenario was based on the data from 1975 to 2005, while the future scenarios were based on the data from 2020s (2025–2054) and 2050s (2055–2084). The HBV hydrological model used to assess the impact on streamflow. The HBV model showed good statistical performance in simulating the impact of climate change on streamflow, with a coefficient of determination (R<sup>2</sup>) of 0.88 and Nash-Sutcliffe Efficiency (NSE) of 0.77 for monthly calibration, and R<sup>2</sup> of 0.86 and NSE of 0.83 for monthly validation. The impacts quantified using the mean monthly changes in precipitation, maximum and minimum temperatures. The bias-corrected precipitation and temperature showed a reasonable increase in both future periods for both RCP 4.5 and RCP 8.5 scenarios. These changes in climate variables resulted in a decrease in mean annual streamflow by 1.6 and 3.5% for RCP 4.5 and by 4.6 and 4.9% for RCP 8.5 scenarios of the 2020s and 2050s, respectively. Based on the analysis that predicted a drop in precipitation during the months, and seasons and an increase in precipitation during the <i>Belg</i> season, with a corresponding decrease and rise in stream flow throughout the watershed. So to offset the variation in the watershed, community should adopt various; Soil and water conservation technologies, Using drought tolerant crops, Implementing various trees and appropriate design and applying a water harvesting structure like in-situ, internal or micro catchment, external or macro catchment water harvesting and Surface runoff harvesting. This result offers useful information for current and future water resource management in the basin and similar other watershed in the country.

Identifying managed aquifer recharge and rain water harvesting sites and structures for storing non-conventional water using GIS-based multi-criteria decision analysis approach

In arid climates, conventional water resources are severely limited and stressed in the face of rapid population growth and future climate change. So, it is necessary to find alternative non-conventional water resources for use in drought situations. Additionally, the non-conventional water resources in these areas are not sufficient to meet future water demand. Therefore, non-conventional water resources can be adopted as a strategic reserve to bridge the gap between water supply and demand in case of emergency and drought events. These resources might include rainwater harvesting, treated wastewater, and desalinated seawater. Managed aquifer recharge (MAR) can be applied to store these resources in the hydrogeological system using Geo information System—Multi Criteria Decision Analysis (GIS-MCDA) approach for determining the suitable MAR location for storage. North-west Kingdom of Saudi Arabia area was chosen for this study because it is extremely arid, has high potential for social and economic development, and it has newly constructed non-conventional water infrastructures distributed throughout the area including water desalination plants, Tertiary Sewage Effluent (TSE) waste water plants, and flash-flood storage dams. To identify the suitable MAR site location and structure, different data related to aquifer hydrogeology, surface hydrology, hydrometeorology, and water quality were applied. Then, GIS-MCDA holistic approach was applied with aid of ordered weighting average (OWA) technique. Finally, two maps were created to show the MAR location and structure type. Potential map indicates that ~ 18.85% of the area is suitable for MAR installations. About 0.17% of the total area exhibited very high potential, where infiltration ponds can be applied, 1.86% had high potential for construction of check dams with diversion channels, and 16.82% had moderate potential for installation of recharge wells. Additionally, 56 MAR structures were proposed and a map showing their locations has been created. Thus, results indicated that the study area is promising for MAR installation. These maps could aid the decision makers to propose a sustainable development plan for the future water resources of the area.

Theoretical and experiment optimization research of a frequency up-converted piezoelectric energy harvester based on impact and magnetic force

Harvesting environmental vibrations to power electronic components is an essential approach for addressing the power supply challenge in MEMS. However, conventional vibration energy harvesting systems frequently suffer from limited frequency bandwidth and high-frequency deficiencies. This paper proposes a novel up-frequency structure for piezoelectric vibration energy harvesting (VEH) that relies on both nonlinear magnetic force and piecewise linear force. The proposed VEH’s nonlinear dynamic characteristics are analyzed theoretically, and an experimental prototype machining and vibration test platform are constructed. Theoretical and experimental results are compared and analyzed by conducting basic experiments and key parameter optimization experiments. The research results demonstrate that the proposed VEH can efficiently harvest vibration energy in low-frequency and wide-band environments. Regarding the system parameters, higher vibration acceleration results in increased output voltage and wider working frequency bandwidth. Reducing the gap distance enhances piecewise linear vibration, which broadens the working frequency bandwidth. Furthermore, the proposed VEH’s ability to harvest low-frequency vibrations can be enhanced by reducing the magnet distance, thereby reducing the linear resonance frequency of the system. The findings of this study offer valuable insights for advancing the engineering application of MEMS self-power supply technology.

Geospatial identification of possible rainwater harvesting locations within a high-altitude Gilgit River basin, Pakistan

The management of water resources is no longer an option but a necessity especially in countries with a high rate of population growth like Pakistan. Pakistan has a high-water scarcity, an extremely varying topography, and is also one of the countries encountering the problem of climate change. Therefore, prudent utilization of available water resources is a matter in the plains of Pakistan as in its high-altitude regions. Instead of wasting water which is a valuable resource, rainwater harvesting is a way of saving rainwater as an alternative source of fresh water for better use. The aim of this study was to search for potential rainwater-harvesting areas in a high-altitude Gilgit River basin. This research employed the SCS-CN technique in estimating surface runoff in the GIS environment. The geospatial study used four input parameters: slope of the land, land covers, surface runoff and drainage density. The research concluded that some lands, especially those that are deserted in dry area and agricultural lands, can serve as the sites of rainwater harvesting, with only 4% of area that was highly suitable for the purpose. Nevertheless, 37% of the investigated area was shown as totally unviable for rainwater collection installations because of steep slopes and substantial volume of snow. Simultaneously, the rainwater storage design solutions suggested were check dam, percolation tank, and agricultural ponds with the area of 3.5%, 1%, and 0.75% of the given land area, respectively, for rainwater harvesting. The locations of potential catchment and planned rainwater harvesting structures would assist the local authorities and the policy makers to provide plans and design on the construction of water storages and also the optimization of water use.

Case study: Design and properties of acoustic energy harvester

Converting acoustic energy into electric energy can not only suppress environmental noise but also provide energy supply, which is a potential way to solve the bottleneck problem of energy supply in wireless sensor networks (WSNs). An acoustic energy harvester structure and circuit system combining Helmholtz resonance effect with piezoelectric effect are proposed in this article. The band gap characteristics of the designed acoustic energy harvester are analyzed by plane wave expansion (PWE) theory and experiment. The substrate of Helmholtz resonator is made from piezoelectric sheet, and the acoustic energy harvester structure is arranged periodically. When the incident noise frequency keeps coincidence with the resonant frequency, the conversion efficiency goes high up to 21.3%. The influence of series and parallel connection of piezoelectric elements on the acoustic to electric energy is observed. The AC-DC conversion circuit is designed with rectifier bridge, and the energy storage circuit is designed with supercapacitor. The power obtained from the acoustic to electric energy conversion system is 1523 mW. Application tests indicate that the noise suppresses, energy conversion, and energy storage can be realized at the same time by the proposed acoustic energy harvester system.

Design of Rain Water Harvesting System for Efficient Water Scarcity and Flood Management in India

Areas experiencing extensive floods during the rainy season and water scarcity in winter require efficient water resource management. Economical water-harvesting structures such as drystone masonry and upstream-wall cement masonry, with heights ranging from 1 to 2.5 meters, are constructed for catchments smaller than 10, 10 to 20, and 20 to 30 hectares, respectively, utilizing locally sourced materials. These constructions offer significant cost-effectiveness for the location, boasting a B:C ratio of 3.5:1. In certain areas of Assam, Garh structures are constructed, featuring large and lengthy embankments on both sides with an open central section for water flow. Within paddy fields, the entire area is partitioned into small square segments, creating small embankments known as "Dara." which store rainwater for cultivation. Across the entire Western Himalayan region, encompassing Jammu, Himachal Pradesh, and Northern Uttaranchal, Guhl serves as a standardized water harvesting technique. Notably, in Akola and Chittoor districts, the establishment of farm ponds has significantly boosted crop and livestock productivity, along with farm income. Additional irrigation has notably enhanced the yield of various rainfed crops such as pigeon pea, chickpea, groundnut, cotton, and vegetables, as well as mango and coconut plants, with improvements ranging from 5 to 72%. With the availability of harvested rainwater for supplemental irrigation, farmers have also planted additional fruit trees, resulting in increased productivity of existing fruit trees, such as mango (39%) in Chittoor district and coconut (51%) in Vellore district. Expanding the number of rainwater harvesting structures could potentially reduce runoff within the basin by up to 60%. The implementation of Doha Models, involving percolation tanks dug along the length of lower-order seasonal streams in Jalna district of Maharashtra, has increased cropping intensity from 129% to 132%. Remarkably, five out of seven crops have demonstrated a relatively higher percentage increase in yields. The optimal productivity of harvested water is achieved when efficient application methods such as micro-irrigation are employed, targeting high-value crops.

Advanced 3D-printed PVDF/BT piezoelectric energy harvester with a bio-inspired 3D structure for a self-powered smart mouse

Piezoelectric polymers such as poly(vinylidene fluoride) (PVDF) exhibit remarkable flexibility, lightweight, durability, and biocompatibility compared to their ceramic counterparts. This unique characteristic makes them highly suitable for harvesting mechanical vibrations. However, conventional manufacturing methods mainly result in two-dimensional (2D) piezoelectric energy harvester (PEHs) structures. This confines the internal stress and, as a result, limits their potential voltage output. This study introduces an innovative bio-inspired three-dimensional (3D) structure crafted through fused deposition modeling (FDM). Barium titanate (BT) nanoparticles were added as piezoelectric fillers to improve the performance of the PEH. The obtained nanocomposite was poled under optimal poling conditions, achieving a β-phase fraction of 95,72 %, a piezoelectric charge coefficient (d33) of 28 pC/N, and a permittivity of 24.2 at 100 Hz. A parametric study was performed through numerical analysis, resulting in an effective and optimized structural configuration. The combined excellent piezoelectric properties of the nanocomposite with the optimized structure enabled the PEH to generate an open-circuit voltage of 30.8 V, enabling it to charge a commercial 1 μF capacitor to 25 V in just 260 s. The bioinspired PEH demonstrates its practical application by powering an innovative device known as the "smart mouse," showcasing its utility and potential in real-world applications.

A piezoelectric and electromagnetic hybrid energy harvester based on two-stage magnetic coupling

Traditional piezoelectric energy harvesters cannot adapt to environmental energy with low frequency, wideband, and randomness because of the narrow working bandwidth. The introduction of magnetic coupling can improve the narrow-band characteristics of piezoelectric energy harvesting structures. To explore more efficient broadband methods, this paper designs a piezoelectric and electromagnetic hybrid energy harvester (PEEH) based on two-stage magnetic coupling to realize the expansion of piezoelectric energy harvesting bandwidth. In this paper, the magnetic pole alternating frequency is changed and the output of the structure is tested, and the operating frequency bands under different alternating frequencies are compared according to the test results. It can be seen from the experimental results that the output performance of the structure is obviously improved by increasing the AC frequency of the magnetic pole while reducing the optimal frequency point of the structure. When the number of magnets in the rotor magnet array is 6, increasing the pole alternating frequency can effectively improve the output performance of the electromagnetic unit when the rotor speed is low, and can also increase the maximum output voltage and energy harvest bandwidth of the piezoelectric unit by 189% and 150%, respectively. Therefore, by increasing the alternating frequency of magnetic poles, the output voltage of the structure can be improved, and the bandwidth of the structure can be broadened.

The Latest Advances in Ink-Based Nanogenerators: From Materials to Applications.

Nanogenerators possess the capability to harvest faint energy from the environment. Among them, thermoelectric (TE), triboelectric, piezoelectric (PE), and moisture-enabled nanogenerators represent promising approaches to micro-nano energy collection. These nanogenerators have seen considerable progress in material optimization and structural design. Printing technology has facilitated the large-scale manufacturing of nanogenerators. Although inks can be compatible with most traditional functional materials, this inevitably leads to a decrease in the electrical performance of the materials, necessitating control over the rheological properties of the inks. Furthermore, printing technology offers increased structural design flexibility. This review provides a comprehensive framework for ink-based nanogenerators, encompassing ink material optimization and device structural design, including improvements in ink performance, control of rheological properties, and efficient energy harvesting structures. Additionally, it highlights ink-based nanogenerators that incorporate textile technology and hybrid energy technologies, reviewing their latest advancements in energy collection and self-powered sensing. The discussion also addresses the main challenges faced and future directions for development.