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At least 163 records · Page 9

Roadmap on energy harvesting materials

Ambient energy harvesting has great potential to contribute to sustainable development and address growing environmental challenges. Converting waste energy from energy-intensive processes and systems (e.g. combustion engines and furnaces) is crucial to reducing their environmental impact and achieving net-zero emissions. Compact energy harvesters will also be key to powering the exponentially growing smart devices ecosystem that is part of the Internet of Things, thus enabling futuristic applications that can improve our quality of life (e.g. smart homes, smart cities, smart manufacturing, and smart healthcare). To achieve these goals, innovative materials are needed to efficiently convert ambient energy into electricity through various physical mechanisms, such as the photovoltaic effect, thermoelectricity, piezoelectricity, triboelectricity, and radiofrequency wireless power transfer. By bringing together the perspectives of experts in various types of energy harvesting materials, this Roadmap provides extensive insights into recent advances and present challenges in the field. Additionally, the Roadmap analyses the key performance metrics of these technologies in relation to their ultimate energy conversion limits. Building on these insights, the Roadmap outlines promising directions for future research to fully harness the potential of energy harvesting materials for green energy anytime, anywhere.

14 SOLAR ENERGY↗

Biomass, spacing and planting design influence cut-and-chip harvesting in hybrid poplar

Hybrid poplar is a woody crop grown for the production of bioenergy, biofuels and bioproducts. Harvesting is often the largest single cost in the production system and the development and optimization of equipment is evolving. Here, the objective of this study was to evaluate the performance of a single-pass, cut-and-chip harvesting operation in commercial plantings that included four cultivars, two spacing treatments, and two coppice planting designs (dedicated, and interplanted with sawtimber). Approximately 15 h of harvesting using a New Holland 9080 forage harvester equipped with a purpose-built coppice header was monitored over four days. Stand biomass ranged between 34 and 78 Mg ha –1 of fresh biomass and effective material capacity (C m ) of the harvester ranged from 10 to 78 Mg h –1 of fresh biomass excluding headland activities. Tree spacing had a significant effect on C m but cultivar and planting design did not. The treatments did not have discernible effects on machine fuel consumption (mean 83 L h –1 ; σ 16.4) or crop-specific fuel consumption for fresh biomass (mean 1.34 L Mg –1 ; σ 0.31). Crop-specific fuel consumption was positively correlated with engine load, and negatively correlated with standing biomass; this result was statistically significant but negligible (<1%) in terms of liters of fuel used for each additional Mg ha –1 of stand biomass for engine loads ranging between 30% and 110%.

59 BASIC BIOLOGICAL SCIENCES↗

Systematic parameter study of a nonlinear electromagnetic energy harvester with matched magnetic orientation: Numerical simulation and experimental investigation

Here, this paper reports the systematic parameter study of a tristable nonlinear electromagnetic energy harvester for ambient low-frequency vibration. Numerical simulations and experimental investigations are performed on the harvester which consists of a cantilever beam, a tip coil, two tip magnets and two external side magnets. The external side magnets are deployed symmetrically along a concave surface parallel to the trajectory of the cantilever tip with a controllable distance so that the magnetic orientation of the tip magnets are matched with that of the side magnets. Therefore, instead of the ternary position parameters (d, h, α), a binary parameters pair (d 0 , d) is used to characterize the position of the side magnets and the performance of the energy harvester. The magnetic force and magnetic field on the cantilever tip therefore depend on the relative distance in the tip displacement direction between the tip magnets and side magnets, but is independent of the position of the side magnets on the concave surface. The magnetic force (field)-distance relationship is measured experimentally and curve fitted to obtain explicit expressions, in order to characterize the magnetic force (field) when the side magnets are placed at varied positions along the concave surface. Numerical simulation is, then, performed to predict the electromagnetic voltage output and the bandwidth of the energy harvester. The simulation results coincided with the measured data. Significant broadband response is obtained experimentally and the maximum RMS power output is 40.2 mW at 0.45 g of excitation. Furthermore, the proposed structure showcasing the matched magnetic orientation is characterized by the binary parameters pair (d 0 , d) and the systematic parametric approach could contribute to the design and study of nonlinear broadband energy harvesters.

30 DIRECT ENERGY CONVERSION↗

Harvesting Mechanical and Thermal Energy by Combining ZnO Nanowires and NiTi Shape Memory Alloy

In the expanding world of small scale energy harvesting, the ability to combine thermal and mechanical harvesting is growing ever more important. Here, we demonstrate the feasibility of using ZnO nanowires to harvest both mechanical and low-quality thermal energy in simple, scalable devices. These devices were fabricated on kapton films and used ZnO nanowires with the same growth direction to assure alignment of the piezoelectric potentials of all of the wires. Mechanical harvesting from these devices was demonstrated using a periodic application of force, modeling the motion of the human body. Tapping the device from the top of the device with a wood stick, for example yielded an Open Circuit Voltage (OCV) of 0.2 - 4 V, which is in an ideal range for device applications. In order to demonstrate thermal harvesting from low quality heat sources, a commercially available Nitinol (Ni-Ti alloy) foil was attached to the nanowire piezoelectric device to create a compound thermoelectric. When bent at room temperature and then heated to 50°C, the Nitinol foil was restored to its original flat shape, which yielded an output voltage of nearly 1 V from the ZnO nanowire device.

36 MATERIALS SCIENCE↗

Renewal of Collaborative Research: Economically viable Forest Harvesting Practices that Increase Carbon Sequestration

This technical report covers a 3-year cooperative agreement between the University of Maine and the Northeastern Forest Experiment Station that focused on the characterization of forest stands and the assessment of forest carbon storage (see attached for detailed description of the project). The goal of this work was to compare estimates of forest C storage made via remeasurement of FIA-type plots with eddy flux measurements. In addition to relating whole ecosystem estimates of carbon storage to changes in aboveground biomass, we explored methodologies by partitioning growth estimates from periodic inventory measurements into annual estimates. In the final year, we remeasured plots that were subject to a shelterwood harvest over the winter of 2001-02 to assess the production of coarse woody debris by this harvest, to remeasure trees in a long-term stand first established by NASA, to carry out other field activities at Howland, and, to assess the importance of downed and decaying wood as well as standing dead trees to the C inputs to harvested and non harvested plots.

54 ENVIRONMENTAL SCIENCES↗

Biocompatible and Flexible Hydrogel Diode‐Based Mechanical Energy Harvesting

Energy harvesting devices which convert low frequency mechanical energy sources such as human motions and ocean waves into electricity are attractive for powering portable devices and for green‐energy generation. To date the state‐of‐the‐art mechanical energy harvesting devices can only work efficiently at high vibration frequencies. Here, a biocompatible and flexible mechanical energy harvesting device is reported utilizing ionic diode as the transducer. This device utilizes the redistribution of cations and anions at the two hydrogel electrodes under stress to convert mechanical energy to electricity. It is shown that the device can be operated at low frequencies with high output current, e.g., 13.5 µA cm −2 , owing to the high ion concentration and unique working mechanism of the device. Moreover, the output current density and power density can be improved further by employing a multilayer configuration. By stacking five units with parallel structure, the hydrogel diode device can generate an output current of 64.3 µA cm −2 and power density of 0.48 µW cm −2 . Considering the very high electric energy density of ionic devices, the hydrogel energy harvesting device demonstrated herein paves a way for efficient mechanical energy harvesting from many common low frequency sources.

Zhou, Yue↗

A Membrane-Associated Light-Harvesting Model is Enabled by Functionalized Assemblies of Gene-Doubled TMV Proteins

Photosynthetic light harvesting requires efficient energy transfer within dynamic networks of light-harvesting complexes embedded within phospholipid membranes. Artificial light-harvesting models are valuable tools for understanding the structural features underpinning energy absorption and transfer within chromophore arrays. Here, a method for attaching a protein-based light-harvesting model to a planar, fluid supported lipid bilayer (SLB) is developed. The protein model consists of the tobacco mosaic viral capsid proteins that are gene-doubled to create a tandem dimer (dTMV). Assemblies of dTMV break the facial symmetry of the double disk to allow for differentiation between the disk faces. A single reactive lysine residue is incorporated into the dTMV assemblies for the site-selective attachment of chromophores for light absorption. Further, on the opposing dTMV face, a cysteine residue is incorporated for the bioconjugation of a peptide containing a polyhistidine tag for association with SLBs. The dual-modified dTMV complexes show significant association with SLBs and exhibit mobility on the bilayer. The techniques used herein offer a new method for protein-surface attachment and provide a platform for evaluating excited state energy transfer events in a dynamic, fully synthetic artificial light-harvesting system.

59 BASIC BIOLOGICAL SCIENCES↗

Life cycle assessment of novel technologies for algae harvesting and oil extraction in the renewable diesel pathway

There are many challenges and technical barriers to implementation of a viable commercial process to produce algae-based biofuels. Biofuels made from algae must typically go through a complicated series of unit processes for algae cultivation, harvesting, dewatering, oil extraction, conversion, and other logistical steps. The National Alliance for Advanced Biofuels and Bioproducts (NAABB) was developed to produce new technologies to be implemented by the algal biofuel industry in an effort to improve the process economics and environmental benefits associated with algae fuels. This LCA study investigated the environmental impacts associated with four harvesting and two extraction technologies developed by NAABB researchers. Gate-to-gate LCA results show that all novel technologies appear to have the potential to provide at least modest decreases in greenhouse gas (GHG) emissions compared to current default algae process technologies. 14 scenarios of different combinations of harvesting and extraction unit operations were further evaluated in the context of the full life cycle for producing algae-based renewable diesel. Results indicate that selection of a particular technology for a unit operation can have consequences that affect other stages of the full biofuels life cycle, both upstream and downstream from the unit operation in question. Considering material and energy inputs, operation efficiency, impacts on on-site recycled energy, and co-products credits, acoustic harvesting followed by acoustic oil extraction give the best performance on the overall lifecycle, which reduce the GHG emissions by roughly 45% compared to the base case. LCA modeling also demonstrates that co-products produced at various points of the value chain, for use within or outside the algae biofuels system boundary, considerably affect the LCA results beyond harvesting and extraction unit processes.

59 BASIC BIOLOGICAL SCIENCES↗

Solid-phase isotope harvesting of 88 Zr from a radioactive ion beam facility

During routine operation of the Facility for Rare Isotope Beams (FRIB), radionuclides will accumulate in both the aqueous beam dump and along the beamline in the process of beam purification. These byproduct radionuclides, many of which are far from stability, can be collected and purified for use in other scientific applications in a process called isotope harvesting. In this work, the viability of 88 Zr harvesting from solid components was investigated at the National Superconducting Cyclotron Laboratory. A secondary 88 Zr beam was stopped in a series of collectors comprised of Al, Cu, W, and Au foils. Here, this work details irradiation of the collector foils and the subsequent radiochemical processing to isolate the deposited 88 Zr (and its daughter 88 Y) from them. Total average recovery from the Al, Cu, and Au collector foils was (91.3 ± 8.9) % for 88 Zr and (95.0 ± 5.8) % for 88 Y, respectively, which is over three times higher recovery than in a previous aqueous-phase harvesting experiment. The utility of solid-phase isotope harvesting to access elements such as Zr that readily hydrolyze in near-neutral pH aqueous conditions has been demonstrated for application to harvesting from solid components at FRIB.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗

An assessment of nonindustrial private forest landowner willingness to harvest woody biomass in support of bioenergy production in Mississippi: A contingent rating approach

Abstract: The economic feasibility of utilizing woody biomass to produce biofuel lies in the willingness to harvest by non-industrial private forest (NIPF) landowners, who control 71% of forestland in the southern United States. A mail survey was distributed to NIPF landowners throughout Mississippi to elicit their preferences concerning the utilization of logging residues from harvesting operations to produce bioenergy. When presented with hypothetical situations that compared the bioenergy utilization harvesting attributes along with those of standard clearcutting in pine plantations, more landowners preferred those associated with the bioenergy utilization scenarios, even when more money was offered for the standard clearcutting option. Older landowners with larger landholdings were less likely to prefer the bioenergy scenarios. Landowners with more formal education who were financially motivated, considered habitat management an important goal, and thought global climate change was an important issue, were more likely to prefer the bioenergy utilization scenario over the standard clearcut. This indicates that a market for logging residues, in the form of wood-based bioenergy, could increase NIPF landowner harvest rates based solely on the different harvesting attributes, and that most woody biomass feedstocks from pine plantations would be available for the production of bioenergy in Mississippi.

Bioenergy↗

Light-harvesting antenna complexes in the moss Physcomitrella patens: implications for the evolutionary transition from green algae to land plants

Plants have successfully adapted to a large range of terrestrial environments during their evolution. To elucidate the evolutionary transition of light-harvesting antenna proteins from green algae to land plants, the moss Physcomitrella patens is ideally placed basally among land plants. Compared to the genomes of green algae and land plants, the P. patens genome codes for more diverse and redundant light-harvesting antenna proteins. It also encodes Lhcb9, which has characteristics not found in other light-harvesting antenna proteins. The unique complement of light-harvesting antenna proteins in P. patens appears to facilitate protein interactions that include those lost in both green algae and land plants with regard to stromal electron transport pathways and photoprotection mechanisms. This review will highlight unique characteristics of the P. patens light-harvesting antenna system and the resulting implications about the evolutionary transition during plant terrestrialization.

59 BASIC BIOLOGICAL SCIENCES↗

Efficient Light Harvesting Biotic–Abiotic Nanohybrid System Incorporating Atomically Thin van der Waals Transition Metal Dichalcogenides

Inspired by nature’s light harvesting complex architectures, which bring together, in one unit, several active nanocomponents to harvest light and to flow the harvested energy in precise directions and places, we designed and assembled a biotic/abiotic stepwise energy transfer nanohybrid system that is based on an atomically thin, two-dimensional (2D) van der Waals semiconductor, colloidal quantum dots, and a light harvesting protein. We utilized the van der Waals semiconductor as a 2D platform for bottom-up assembly, connecting nanocomponents via electrostatic self-assembly and layer-by-layer polyelectrolyte deposition. Through bandgap engineering of the self-assembled active components, we created conditions for efficient directional stepwise energy transfer, from optically excited quantum dots, to proteins and finally to the 2D van der Waals semiconductor, here molybdenum diselenide (MoSe 2 ). A field effect transistor incorporating the biotic/abiotic nanohybrid was demonstrated to exhibit enhanced spectral responsivity when compared to the pristine device (2D van der Waals semiconductor only). Furthermore, this is because the biotic/abiotic nanohybrid exhibits enhanced absorption cross section and enhanced light harvesting through the addition of quantum dots and proteins next to MoSe 2 , which in turn leads to enhanced exciton generation in MoSe 2 via energy transfer from quantum dots to proteins and finally to MoSe 2 .

77 NANOSCIENCE AND NANOTECHNOLOGY↗

Structures of a phycobilisome in light-harvesting and photoprotected states

Phycobilisome (PBS) structures are elaborate antennae in cyanobacteria and red algae 1,2 . These large protein complexes capture incident sunlight and transfer the energy through a network of embedded pigment molecules called bilins to the photosynthetic reaction centres. However, light harvesting must also be balanced against the risks of photodamage. A known mode of photoprotection is mediated by orange carotenoid protein (OCP), which binds to PBS when light intensities are high to mediate photoprotective, non-photochemical quenching 3-6 . Here we use cryogenic electron microscopy to solve four structures of the 6.2 MDa PBS, with and without OCP bound, from the model cyanobacterium Synechocystis sp. PCC 6803. The structures contain a previously undescribed linker protein that binds to the membrane-facing side of PBS. For the unquenched PBS, the structures also reveal three different conformational states of the antenna, two previously unknown. The conformational states result from positional switching of two of the rods and may constitute a new mode of regulation of light harvesting. Further, only one of the three PBS conformations can bind to OCP, which suggests that not every PBS is equally susceptible to non-photochemical quenching. In the OCP-PBS complex, quenching is achieved through the binding of four 34kDa OCPs organized as two dimers. The complex reveals the structure of the active form of OCP, in which an approximately 60Å displacement of its regulatory carboxy terminal domain occurs. Finally, by combining our structure with spectroscopic properties 7 , we elucidate energy transfer pathways within PBS in both the quenched and light-harvesting states. Collectively, our results provide detailed insights into the biophysical underpinnings of the control of cyanobacterial light harvesting. The data also have implications for bioengineering PBS regulation in natural and artificial light-harvesting systems.

59 BASIC BIOLOGICAL SCIENCES↗

Structure–performance relationships for cantilever-type piezoelectric energy harvesters

This study provides comprehensive analysis of the structure–performance relationships in cantilever-type piezoelectric energy harvesters. It provides full understanding of the effect of all the practical global control variables on the harvester performance. The control variables considered for the analysis were material parameters, areal and volumetric dimensions, and configuration of the inactive and active layers. Experimentally, the output power density of the harvester was maximum when the shape of the beam was close to a square for a constant bending stiffness and a fixed beam area. Through analytical modeling of the effective stiffness for the piezoelectric bimorph, the conditions for enhancing the bending stiffness within the same beam volume as that of a conventional bimorph were identified. The harvester configuration with beam aspect ratio of 0.86 utilizing distributed inactive layers exhibited an giant output power of 52.5 mW and power density of 28.5 mW cm{sup −3} at 30 Hz under 6.9 m s{sup −2} excitation. The analysis further indicates that the trend in the output power with varying damping ratio is dissimilar to that of the efficiency. In order to realize best performance, the harvester should be designed with respect to maximizing the magnitude of output power.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

A small-form-factor piezoelectric vibration energy harvester using a resonant frequency-down conversion

While environmental vibrations are usually in the range of a few hundred Hertz, small-form-factor piezoelectric vibration energy harvesters will have higher resonant frequencies due to the structural size effect. To address this issue, we propose a resonant frequency-down conversion based on the theory of dynamic vibration absorber for the design of a small-form-factor piezoelectric vibration energy harvester. The proposed energy harvester consists of two frequency-tuned elastic components for lowering the first resonant frequency of an integrated system but is so configured that an energy harvesting beam component is inverted with respect to the other supporting beam component for a small form factor. Furthermore, in order to change the unwanted modal characteristic of small separation of resonant frequencies, as is the case with an inverted configuration, a proof mass on the supporting beam component is slightly shifted toward a second proof mass on the tip of the energy harvesting beam component. The proposed small-form-factor design capability was experimentally verified using a fabricated prototype with an occupation volume of 20 × 39 × 6.9 mm{sup 3}, which was designed for a target frequency of as low as 100 Hz.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

A nonlinear piezoelectric energy harvester for various mechanical motions

This study presents a nonlinear piezoelectric energy harvester with intent to scavenge energy from diverse mechanical motions. The harvester consists of four piezoelectric cantilever beams, a cylindrical track, and a ferromagnetic ball, with magnets integrated to introduce the magnetic coupling between the ball and the beams. The experimental results demonstrate that the harvester is able to collect energy from various directions of vibrations. For the vibrations perpendicular to the ground, the maximum peak voltage is increased by 3.2 V and the bandwidth of the voltage above 4 V is increased by more than 4 Hz compared to the results obtained when using a conventional design. For the vibrations along the horizontal direction, the frequency up-conversion is realized through the magnetic coupling. Moreover, the proposed design can harvest energy from the sway motion around different directions on the horizontal plane. Harvesting energy from the rotation motion is also achieved with an operating bandwidth of approximately 6 Hz.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Design and fabrication of non silicon substrate based MEMS energy harvester for arbitrary surface applications

Internet of Things (IoT) uses MEMS sensor nodes and actuators to sense and control objects through Internet. IOT deploys millions of chemical battery driven sensors at different locations which are not reliable many times because of frequent requirement of charging & battery replacement in case of underground laying, placement at harsh environmental conditions, huge count and difference between demand (24 % per year) and availability (energy density growing rate 8% per year). Energy harvester fabricated on silicon wafers have been widely used in manufacturing MEMS structures. These devices require complex fabrication processes, costly chemicals & clean room. In addition to this silicon wafer based devices are not suitable for curved surfaces like pipes, human bodies, organisms, or other arbitrary surface like clothes, structure surfaces which does not have flat and smooth surface always. Therefore, devices based on rigid silicon wafers are not suitable for these applications. Flexible structures are the key solution for this problems. Energy transduction mechanism generates power from free surrounding vibrations or impact. Sensor nodes application has been purposefully selected due to discrete power requirement at low duty cycle. Such nodes require an average power budget in the range of about 0.1 microwatt to 1 mW over a period of 3-5 seconds. Energy harvester is the best alternate source in contrast with battery for sensor node application. Novel design of Energy Harvester based on cheapest flexible non silicon substrate i.e. cellulose acetate substrate have been modeled, simulated and analyzed on COMSOL multiphysics and fabricated using sol-gel spin coating setup. Single cantilever based harvester generates 60-75 mV peak electric potential at 22Hz frequency and approximately 22 µW power at 1K-Ohm load. Cantilever array can be employed for generating higher voltage by replicating this structure. This work covers design, optimization, fabrication of harvester and schottky diodes based voltage multiplier.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

A bottom-up perspective on photodynamics and photoprotection in light-harvesting complexes using anti-Brownian trapping

Single-molecule fluorescence spectroscopy allows direct, real-time observation of dynamic photophysical changes in light harvesting complexes. The Anti-Brownian ELectrokinetic (ABEL) trap is one such single-molecule method with useful advantages. This approach is particularly well-suited to make detailed spectroscopic measurements of pigment-protein complexes in solution phase because it enables extended-duration single-molecule observation by counteracting Brownian motion. This Perspective summarizes recent contributions by the authors and others that have utilized the unique capabilities of the ABEL trap to advance our understanding of phycobiliproteins and the phycobilisome complex, the primary light-harvesting apparatus of cyanobacteria. Monitoring the rich spectroscopic data from these measurements, which include brightness, fluorescence lifetime, polarization, and emission spectra, among other measurable parameters, has provided direct characterization of pigments and energy transfer pathways in the phycobilisome, spanning scales from single pigments and monomeric phycobiliproteins to higher order oligomers and protein-protein interactions of the phycobilisome complex. Importantly, new photophysical states and photodynamics were observed to modulate the flow of energy through the phycobilisome and suggest a previously unknown complexity in phycobilisome light harvesting and energy transport with a possible link to photoadaptive or photoprotective functions in cyanobacteria. Here, beyond deepening our collective understanding of natural light-harvesting systems, these and future discoveries may serve as inspiration for engineering improved artificial light-harvesting technologies.

14 SOLAR ENERGY↗