Eric K. Anderson

Conformal piezoelectric energy harvesting and storage from motions of the heart, lung, and diaphragm

Significance Heart rate monitors, pacemakers, cardioverter-defibrillators, and neural stimulators constitute broad classes of electronic implants that rely on battery power for operation. Means for harvesting power directly from natural processes of the body represent attractive alternatives for these and future types of biomedical devices. Here we demonstrate a complete, flexible, and integrated system that is capable of harvesting and storing energy from the natural contractile and relaxation motions of the heart, lung, and diaphragm at levels that meet requirements for practical applications. Systematic experimental evaluations in large animal models and quantitatively accurate computational models reveal the fundamental modes of operation and establish routes for further improvements. Here, we report advanced materials and devices that enable high-efficiency mechanical-to-electrical energy conversion from the natural contractile and relaxation motions of the heart, lung, and diaphragm, demonstrated in several different animal models, each of which has organs with sizes that approach human scales. A cointegrated collection of such energy-harvesting elements with rectifiers and microbatteries provides an entire flexible system, capable of viable integration with the beating heart via medical sutures and operation with efficiencies of ∼2%. Additional experiments, computational models, and results in multilayer configurations capture the key behaviors, illuminate essential design aspects, and offer sufficient power outputs for operation of pacemakers, with or without battery assist.

Growth and agronomy of miscanthus × giganteus for biomass production

Miscanthus x giganteus is a highly productive, sterile, rhizomatous, C4 perennial grass that should be considered as a feedstock for bioenergy production. Here, we review the current state of research and the future of M. x giganteus biomass production. Since the 1980s, the grass has been studied and used in Europe to produce heat and electricity via combustion. Since 2005, the US government has encouraged research using herbaceous feedstocks for conversion to ethanol for use as transportation fuel. M. x giganteus is being widely studied in the USA because of its potential to produce large quantities of biomass. This review examines the taxonomy and genetics, growth and development, physiology and agronomy, and modeled and potential ‘real-world’ yields of M. x giganteus in Europe and the USA. In addition, the invasiveness and the future perspective of M. x giganteus utility and research in the USA are also considered.

Miscanthus × giganteus Response to Preemergence and Postemergence Herbicides

Abstract Miscanthus is a perennial rhizomatous C4 grass being evaluated in the United States as a potential bioenergy feedstock. Weed control during the first two growing seasons is essential for successful establishment. No herbicides are currently labeled for use in Miscanthus grown for biomass, but herbicides used on field corn might be safe to Miscanthus. Greenhouse experiments were conducted in 2007 and 2008 to evaluate the response of Miscanthus to numerous preemergence (PRE) and postemergence (POST) herbicides. Herbicides with activity only on broadleaf species, whether PRE or POST, did not exhibit injury or reduce Miscanthus biomass. Several herbicides, particularly those with significant activity on grass species, exhibited injury ranging from 6 to 71% (scale of 0 to 100) and/or reduced Miscanthus dry mass by 33 to 78%, especially at the highest rates applied. Field experiments were conducted in 2008 and 2009 with a selection of the herbicides used in the greenhouse experiments to evaluate the response of Miscanthus to herbicides applied PRE, POST and PRE followed by POST. Results from the field experiments generally confirmed those from the greenhouse experiments. PRE herbicides and herbicides with broadleaf-specific activity generally did not produce significant injury or reduce aboveground biomass while herbicides with grass activity tended to cause injury ranging from 22 to 25% and/or reduce biomass by 69 to 78%. With some exceptions, results support prior suppositions that herbicides used in corn are safe to use on Miscanthus and may provide potential herbicide options that growers can use when establishing Miscanthus. Nomenclature: Miscanthus, Miscanthus × giganteus Greef and Deuter ex Hodkinson and Renvoize; corn, Zea mays L.

Agronomic factors in the establishment of tetraploid seeded Miscanthus × giganteus

To meet US renewable fuel mandates, perennial grasses have been identified as important potential feedstocks for processing into biofuels. Triploid Miscanthus × giganteus, a sterile, rhizomatous grass, has proven to be a high‐yielding biomass crop over the past few decades in the European Union and, more recently, in the United States. However, high establishment costs from rhizomes are a limitation to more widespread plantings without government subsidies. A recently developed tetraploid cultivar of M. × giganteus producing viable seeds (seeded miscanthus) shows promise in producing high yields with reduced establishment costs. Field experiments were conducted in Urbana, Illinois from 2011 to 2013 to optimize seeded miscanthus establishment by comparing seeding rates (10, 20, and 40 seeds m−2) and planting methods (drilling seeds at 38 and 76 cm row spacing vs. hydroseeding with and without premoistened seeds) under irrigated and rainfed conditions. Drought conditions in 2011 and 2012 coincided with stand establishment failure under rainfed conditions, suggesting that seeded miscanthus may not establish well in water‐stressed environments. In irrigated plots, hydroseeding without premoistening was significantly better than hydroseeding with premoistening, drilling at 38 cm and drilling at 76 cm with respect to plant number (18%, 54%, and 59% higher, respectively), plant frequency (13%, 30%, and 40% better, respectively), and the rate of canopy closure (18%, 33%, and 43% faster, respectively) when averaged across seeding rates. However, differences in second‐year biomass yields among treatments were less pronounced, as plant size partially compensated for plant density. Both hydroseeding and drilling at rates of 20 or 40 seeds m−2 appear to be viable planting options for establishing seeded miscanthus provided sufficient soil moisture, but additional strategies are required for this new biomass production system under rainfed conditions.

Growth responses and accumulation of cadmium in switchgrass (Panicumvirgatum L.) and prairie cordgrass (Spartinapectinata Link)

Phytoextraction could be an efficient technique to remediate heavy metals from contaminated soils. Identifying bioenergy crops that can be produced successfully on marginal lands, such as those polluted by heavy metals, also reduces the pressure to produce energy crops on land that would otherwise be used to produce food crops. The objective of this study was to determine the phytoremediation capability of two warm season perennials, prairie cordgrass (Spartinapectinata Link, ‘Savoy’) and switchgrass (Panicumvirgatum L., ‘Cave-In-Rock’ (CIR)) through their growth response to cadmium (Cd). Growth rate, Cd tolerance, accumulation and translocation were measured at concentrations of 0 (control), 5, 10, 30, and 50 mg L−1 of Cd mixed with Hoaglands solution in an aerated hydroponic system. Although a reduction of plant growth was observed when the Cd concentration was higher than 10 mg L−1 for both species, there were significant differences in Cd tolerance, translocation and accumulation between species. The tolerance index (Ti) was between 72.5 and 107.1 in Savoy and 48.7 and 75.7 in CIR under Cd concentrations of 50 mg L−1 and 5 mg L−1, respectively. The translocation factor (Tf) for both species was increased with increasing Cd concentration in solution, but the Tf of Savoy was higher than CIR. The highest bio-concentration factor (BCF) of the roots reached 325.7 for Savoy and 144.5 for CIR when the Cd concentration was 5 mg L−1 and the BCF of the shoots in both species was consistently low (13.7 to 16.8 and 4.1 to 6.0 for Savoy and CIR, respectively) indicating higher Cd retention in the roots than shoots. It was concluded that both species could be utilized in phytoremediation when the Cd concentration is less than 10 mg L−1, however Savoy has the higher tolerance, translocation and accumulation capabilities which makes it a better candidate for phytoremediation and biomass production on Cd polluted soils.

Biomass production of herbaceous energy crops in the United States: field trial results and yield potential maps from the multiyear regional feedstock partnership

Current knowledge of yield potential and best agronomic management practices for perennial bioenergy grasses is primarily derived from small‐scale and short‐term studies, yet these studies inform policy at the national scale. In an effort to learn more about how bioenergy grasses perform across multiple locations and years, the U.S. Department of Energy (US DOE)/Sun Grant Initiative Regional Feedstock Partnership was initiated in 2008. The objectives of the Feedstock Partnership were to (1) provide a wide range of information for feedstock selection (species choice) and management practice options for a variety of regions and (2) develop national maps of potential feedstock yield for each of the herbaceous species evaluated. The Feedstock Partnership expands our previous understanding of the bioenergy potential of switchgrass, Miscanthus, sorghum, energycane, and prairie mixtures on Conservation Reserve Program land by conducting long‐term, replicated trials of each species at diverse environments in the U.S. Trials were initiated between 2008 and 2010 and completed between 2012 and 2015 depending on species. Field‐scale plots were utilized for switchgrass and Conservation Reserve Program trials to use traditional agricultural machinery. This is important as we know that the smaller scale studies often overestimated yield potential of some of these species. Insufficient vegetative propagules of energycane and Miscanthus prohibited farm‐scale trials of these species. The Feedstock Partnership studies also confirmed that environmental differences across years and across sites had a large impact on biomass production. Nitrogen application had variable effects across feedstocks, but some nitrogen fertilizer generally had a positive effect. National yield potential maps were developed using PRISM‐ELM for each species in the Feedstock Partnership. This manuscript, with the accompanying supplemental data, will be useful in making decisions about feedstock selection as well as agronomic practices across a wide region of the country.

Impacts of management practices on bioenergy feedstock yield and economic feasibility on Conservation Reserve Program grasslands

Perennial grass mixtures planted on Conservation Reserve Program (CRP) land are a potential source of dedicated bioenergy feedstock. Long‐term nitrogen (N) and harvest management are critical factors for maximizing biomass yield while maintaining the longevity of grass stands. A six‐year farm‐scale study was conducted to understand the impact of weather variability on biomass yield, determine optimal N fertilization and harvest timing management practices for sustainable biomass production, and estimate economic viability at six CRP sites in the United States. Precipitation during the growing season was a critical factor for annual biomass production across all regions, and annual biomass production was severely reduced when growing season precipitation was below 50% of average. The N rate of 112 kg ha−1 produced the highest biomass yield at each location. Harvest timing resulting in the highest biomass yield was site‐specific and was a factor of predominant grass type, seasonal precipitation, and the number of harvests taken per year. The use of N fertilizer for yield enhancement unambiguously increased the cost of biomass regardless of the harvest timing for all six sites. The breakeven price of biomass at the farmgate ranged from

Switchgrass and Prairie Cordgrass Response to Foliar- and Soil-Applied Herbicides

37 to

Miscanthus × giganteus response to tillage and glyphosate.

311 Mg−1 depending on the rate of N application, timing of harvesting, and location when foregone opportunity costs were not considered. Breakeven prices ranged from

Assessment of the potential for gene flow from transgenic maize (Zea mays L.) to eastern gamagrass (Tripsacum dactyloides L.)

69 to