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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

All the light we cannot see: Climate manipulations leave short and long‐term imprints in spectral reflectance of trees

Abstract Anthropogenic climate change, particularly changes in temperature and precipitation, affects plants in multiple ways. Because plants respond dynamically to stress and acclimate to changes in growing conditions, diagnosing quantitative plant‐environment relationships is a major challenge. One approach to this problem is to quantify leaf responses using spectral reflectance, which provides rapid, inexpensive, and nondestructive measurements that capture a wealth of information about genotype as well as phenotypic responses to the environment. However, it is unclear how warming and drought affect spectra. To address this gap, we used an open‐air field experiment that manipulates temperature and rainfall in 36 plots at two sites in the boreal‐temperate ecotone of northern Minnesota, USA. We collected leaf spectral reflectance (400–2400 nm) at the peak of the growing season for three consecutive years on juveniles (two to six years old) of five tree species planted within the experiment. We hypothesized that these mid‐season measurements of spectral reflectance capture a snapshot of the leaf phenotype encompassing a suite of physiological, structural, and biochemical responses to both long‐ and short‐time scale environmental conditions. We show that the imprint of environmental conditions experienced by plants hours to weeks before spectral measurements is linked to regions in the spectrum associated with stress, namely the water absorption regions of the near‐infrared and short‐wave infrared. In contrast, the environmental conditions plants experience during leaf development leave lasting imprints on the spectral profiles of leaves, attributable to leaf structure and chemistry (e.g., pigment content and associated ratios). Our analyses show that after accounting for baseline species spectral differences, spectral responses to the environment do not differ among the species. This suggests that building a general framework for understanding forest responses to climate change through spectral metrics may be possible, likely having broader implications if the common responses among species detected here represent a widespread phenomenon. Consequently, these results demonstrate that examining the entire spectrum of leaf reflectance for environmental imprints in contrast to single features (e.g., indices and traits) improves inferences about plant‐environment relationships, which is particularly important in times of unprecedented climate change.

Stefanski, Artur [Department of Forest Resources U↗
DOE OSTI2026

Modeling the Effect of the Heliospheric Magnetic Field on Cosmic Ray Muon Shadows

Shadows cast in the cosmic ray (CR) muon sky by the Sun were located using muon data from the MINOS far detector in Northern Minnesota. The shadows were observed independently across three time periods; near solar minimum, near solar maximum, and over the entire 13 year span of the data. A distribution of muon positions for each shadow was then sampled to simulate CR motions near the Sun using the Parker spiral model of the Heliospheric Magnetic Field (HMF) and a dipole model of the Geomagnetic Field (GMF). The resulting particle distributions were then compared to their position with respect to the Sun. Results show that the Parker spiral model is most consistent with the solar minimum shadow and least consistent with the solar maximum shadow, as expected. The simple Parker spiral is more consistent with the data for a harder CR spectrum than is actually present, indicating the need for a more detailed HMF model. Plausible modifications to the Parker spiral model which would affect the overall shift of the Sun's CR shadow are discussed.

Adamson, P. [Fermilab]↗
DOE OSTI2025

A Novel Sediment Passage Module Design in Support of Standard Modular Hydropower

This document is the Final Technical Report (FTR) for University of Minnesota (UMN) project on the development of a novel sediment (e.g., sand) bypass technology for new stream reach development (NSD). The project duration was slightly over four years and organized over two budget periods (BPs), i.e., BP1 and BP2, with a Go/No-Go review at the end of BP1. The initial technology had a Technology Readiness Level (TRL) of two (2) and, over the life of the project, advanced substantially to TRL 3 or 4.

13 HYDRO ENERGY↗
DOE OSTI2021

The stable isotopes of natural waters at the Marcell Experimental Forest

Here, we present a new data set from the Marcell Experimental Forest (MEF) that compiles water isotope measurements from multiple research catchments, some of which have been studied since the 1960s. The MEF is located in northern Minnesota, USA, and is home to heavily studied and monitored forests, streams, bogs, and fens. Peat-forming systems (bogs and fens) are an important component of the MEF landscape and have a profound impact on the water cycle in these catchments. Within the last decade, analysis of stable isotopes of water (expressed as δD and δ 18 O) has been implemented to characterize the different components of the water budget, and to allow researchers to look at catchment and peatland-specific hydrologic effects in the watershed. This δD and δ 18 O data set of natural waters from MEF catchments is primarily composed of measurements from three peatlands (S1, S2, S6) during an 11-year period. More recently collection and analysis were expanded to also include samples from the Spruce and Peatland Responses Under Changing Environments (SPRUCE) project in the S1 bog, peatlands S3, S4, S5, as well as nearby lakes. We establish a local meteoric water line by analyzing the isotopic composition of precipitation, which fills a void in regional meteoric water lines for Minnesota. Furthermore, we establish baseline isotopic composition for bog outlet streams, bog porewater, aquifer groundwater, overland flow, subsurface stormflow, and snowpack, as well as runoff from the SPRUCE experimental chambers. These data are publicly available and will be expanded upon in the future.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Measuring and modeling soil moisture and runoff at solar farms using a disconnected impervious surface approach

Abstract Ground‐mounted photovoltaic sites are often treated as impervious surfaces in stormwater permits. This ignores the pervious soils beneath and between solar arrays and leads to an overestimation of runoff. Our objective was to improve solar farm stormwater hydrology models by explicitly considering the disconnected impervious nature of solar design and site characteristics. Experimental sites established on utility scale solar farms in Colorado, Georgia, Minnesota, New York, and Oregon had perennial vegetative plantings with mean precipitation ranging from 40.6 to 124.5 cm, and soil texture ranging from loamy sand to clay. Soil moisture measurements were collected beneath arrays, under drip edges, and in the vegetated area between arrays at each site. Hydrus‐3D models for soil moisture and stormwater hydrology were developed that accounted for precipitation falling on solar panels, drip edge redistribution of rainfall, infiltration, and runoff in the pervious areas between solar arrays and beneath panels. Drip edge runoff averaged 3‐ to 10‐times incident precipitation at the New York and Minnesota sites, respectively. Root mean square error values between measured sub‐hourly soil moisture and predicted moisture for large measured single storm events averaged 0.029 across all five sites. Predicted runoff depths were strongly affected by precipitation depth, soil texture, soil profile depth, and soil bulk density. Runoff depths across the five experimental sites averaged 13%, 25%, and 45% of the 2‐, 10‐, and 100‐year design storm depths, clearly showing that these solar farms do not behave like impervious surfaces, but rather as disconnected impervious surfaces with substantial infiltration of runoff in the vegetated areas between and beneath solar arrays.

Agriculture↗
DOE OSTI2021

Nitrogen and phosphorus cycling in an ombrotrophic peatland: a benchmark for assessing change

Aims Slow decomposition and isolation from groundwater mean that ombrotrophic peatlands store a large amount of soil carbon (C) but have low availability of nitrogen (N) and phosphorus (P). To better understand the role these limiting nutrients play in determining the C balance of peatland ecosystems, we compile comprehensive N and P budgets for a forested bog in northern Minnesota, USA. Methods N and P within plants, soils, and water are quantified based on field measurements. The resulting empirical dataset are then compared to modern-day, site-level simulations from the peatland land surface version of the Energy Exascale Earth System Model (ELM-SPRUCE).

Salmon, Verity G.↗
DOE OSTI2020

Biomass Production of Prairie Cordgrass (Spartina pectinata Link.) Using Urea and Kura Clover (Trifolium ambiguum Bieb.) as a Source of Nitrogen

Abstract Optimizing nitrogen (N) management is an important factor for sustainable perennial biomass systems. However, N application is costly, both financially and environmentally. Our objectives were to determine: (1) N rate and plant spacing effects on yield and yield components of prairie cordgrass swards and (2) fertilizer N replacement value (FNRV) of kura clover in prairie cordgrass-kura clover binary mixtures. Plots were established in Illinois, Minnesota, South Dakota, and Wisconsin, USA, in 2010. Kura clover was transplanted on 30-cm centers in all treatments in which it was a component; prairie cordgrass seedlings were transplanted within the kura clover on 60- and 90-cm centers. Monoculture prairie cordgrass stands were established at the same population densities of mixed stands and fertilized with 0, 75, 150, or 225 kg N ha -1 . Biomass was harvested in the autumn from 2011 to 2013. N (urea), year, plant spacing, and year × plant spacing affected prairie cordgrass production at all locations. Prairie cordgrass yield increased with N application, but the response varied by location. N application tended to increase prairie cordgrass tiller density and consistently increased tiller mass. Prairie cordgrass yield with 0 N was equal to or less than the yield of prairie cordgrass/kura clover mixtures at all locations in 2011 and 2012; however, kura clover provided a FNRV of 25–82 kg N ha -1 to prairie cordgrass in 2013. Kura clover has potential to provide N to prairie cordgrass in binary mixtures of these two species and on land that may not be easily farmed due to wetness.

Energy & Fuels↗
DOE OSTI2021

The nth-plant scenario for blended feedstock conversion and preprocessing nationwide: biorefineries and depots

The sustainability of the biofuel industry depends on the development of a mature conversion technology on a national level that can take advantage of the economies of scale: the nth-plant. Defining the future location and supply logistics of conversion plants is imperative to ultimately transform the nation’s renewable biomass resources into cost-competitive, high-performance feedstock for production of biofuels and bioproducts. Since the US has put restrictions on production levels of conventional biofuels from edible resources, the nation needs to plan for the widespread accessibility and development of the cellulosic biofuel scenario. Conventional feedstock supply systems will be unable to handle cellulosic biomass nationwide, making it essential to expand the industry with an advanced feedstock supply system incorporating a distributed network of preprocessing depots and conversion plants, or biorefineries. Current studies are mostly limited to designing supply systems for specific regions of the country. We developed a national database with potential locations for depots and biorefineries to meet the nation’s target demand of cellulosic biofuel. Blended feedstock with switchgrass and corn stover (harvested by either a two- or three-pass method) are considered in a Mixed Integer Linear Programming model to deliver on-spec biomass that considers both, a desired quantity and quality at the biorefinery. A total delivered feedstock cost that is less than $79.07/dt (2016$) is evaluated for years 2022, 2030, and 2040. In 2022, 124 depots and 59 biorefineries could be supplied with 42.8 million dt of corn stover and switchgrass. In 2030 and 2040, the total accessible biomass could increase to 215% and 393% respectively when compared to 2022. However, an $8/dry tons reduction in targeted delivery cost could reduce total accessible biomass by 67%. Kansas, Nebraska, South Dakota and Texas were identified as potential states with a strong biofuel economy given that they had six or more biorefineries located in all scenarios. In some scenarios, Colorado, Alabama, Georgia, Minnesota, Mississippi and South Carolina would greatly benefit from a depot network as these could only deliver to a biorefinery in a nearby state. To elaborate the impact of a nationwide consideration, the findings were compared with existing literature for different US regions. We also present results for biorefinery capacities that are double, triple, and quadruple in size.

09 BIOMASS FUELS↗
DOE OSTI2019

Study of optimal sizing for residential sorption heat pump system

Gas-driven sorption heat pumps (GDSHP) show significant potential to reduce primary energy use, associated emissions and energy costs for space heating and domestic hot water production in residential applications. This study considered a bivalent heating system consisting of a sorption heat pump and a condensing boiler, and focuses on the optimal heating capacity of each of these components relative to each other. Two bivalent systems were considered: one based on a solid chemisorption cycle (GDSHPA), and one based on a resorption cycle (GDSHPB). Simulations of year-round space heating loads for two single-family houses, one in New York and the other Minnesota, were carried out and the seasonal gas coefficient of performance (SGCOP) calculated. The sorption heat pump’s design heating capacity as a fraction of the bivalent system’s total heating capacity was varied from 0 to 100%. Results show that SGCOP was effectively constant for sorption heat pump design capacity greater than 41% of the peak bivalent GDSHPA design capacity in Minnesota, and 32% for GDSHPB. In New York, these values were 42% and 34% for GDSHPA and GDSHPB respectively. The payback period was also evaluated based on postulated sorption heat pump component costs. The fastest payback was achieved with sorption heat pump design capacity between 22 and 44%.

42 ENGINEERING↗
DOE OSTI2018

Growth performance and stability of hybrid poplar clones in simultaneous tests on six sites

Growth, stability, and genotype x environment (GxE) interaction were investigated for 69 clones after five years at six sites in Minnesota. Fifty-three clones were Populus deltoides x Populus nigra (DxN) crosses, nine were P. deltoides x P. maximowiczi, ten other crosses. Most clones were previously screened for growth and disease resistance in Minnesota. Five-year diameter (DBH) and basal area (BA) at 1.38 m averaged 93.5 mm and 72.11 cm 2 , respectively, over the six sites. DBH site means varied from 109.0 to 79.4 mm. The fastest-growing clone BA was 64% and 49% larger than the mean of the two commercial standards and the mean of the population, respectively. Site, clone, and clone x site effects were highly significant in the ANOVA. The variance component for clone was over twice that of clone x site (GxE), indicating a relatively small reduction in genetic gain due to GxE. Clonal rank did not change between sites. GxE interaction was dominated by relative performance differences of clones on the different sites. Twenty-six percent of clones were stable (little change in growth between sites), 74% unstable. Stability coefficients of the unstable clones varied over a 99% range, indicating the population had high and variable phenotypic plasticity. Only 15% of clones were both stable and fast growing. Seven putatively superior clones, all DxN, were selected for future testing under near-commercial conditions. The results, if representative of other inter-specific Populus populations, indicate it will be difficult, and probably impractical, to reduce GxE with standard quantitative genetics methods in hybrid poplar tree improvement programs without sacrificing productivity gains.

09 BIOMASS FUELS↗
DOE OSTI2011

Status of NOvA

NOvA is a long-baseline neutrino oscillation experiment looking for the appearance of electron neutrinos and antineutrinos in the NuMI neutrino beam. It is comprised of a near detector located on-site at Fermilab, approximately 1 km from the neutrino source and a far detector located 810 km from the source in northern Minnesota. Both detectors are positioned 14 mrad off the beam axis to observe a narrow range of neutrino energies peaked at 2.2 GeV. Construction of the NOvA experiment has begun and the details are outlined below.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2013

Assessment of risk for asthma initiation and cancer and heart disease deaths among patrons and servers due to secondhand smoke exposure in restaurants and bars

Background: Despite efforts to reduce exposure to secondhand smoke (SHS), only 5% of the world’s population enjoy smoke-free restaurants and bars. Methods: Lifetime excess risk (LER) of cancer death, ischaemic heart disease (IHD) death and asthma initiation among non-smoking restaurant and bar servers and patrons in Minnesota and the US were estimated using weighted field measurements of SHS constituents in Minnesota, existing data on tobacco use and multiple dose-response models. Results: A continuous approach estimated a LER of lung cancer death (LCD) of 18×10 –6 (95% CI 13 to 23×10 –6 ) for patrons visiting only designated nonsmoking sections, 80×10 –6 (95% CI 66 to 95×10 –6 ) for patrons visiting only smoking venues/sections and 802×10 –6 (95% CI 658 to 936×10 –6 ) for servers in smoking-permitted venues. An attributable-risk (exposed/ non-exposed) approach estimated a similar LER of LCD, a LER of IHD death about 10 –2 for non-smokers with average SHS exposure from all sources and a LER of asthma initiation about 5% for servers with SHS exposure at work only. These risks correspond to 214 LCDs and 3001 IHD deaths among the general nonsmoking population and 1420 new asthma cases among non-smoking servers in the US each year due to SHS exposure in restaurants and bars alone. Conclusions: Health risks for patrons and servers from SHS exposure in restaurants and bars alone are well above the acceptable level. Restaurants and bars should be a priority for governments’ effort to create smoke-free environments and should not be exempt from smoking bans.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

Assessing Foundation Insulation Strategies for the 2012 International Energy Conservation Code in Cold Climate New Home Construction

Even though the International Energy Conservation Code 2012 (International Code Council 2012) is a model code now available for adoption by individual states, only two cold-climate states have adopted it as their new home energy code. Understanding the resistance to adoption is important in assisting more states to accept the code and engage in deep energy strategies nationwide. This three-part assessment by the NorthernSTAR Building America Partnership was focused on foundation insulation R-values for cold climates and the design, construction, and performance implications. In Section 1, a literature review and attendance at stakeholder meetings held in Minnesota were used to assess general stakeholder interest and concerns about proposed code changes. Section 2 includes drawings of robust foundation insulation systems that were presented at one Minnesota stakeholder meeting to address critical issues and concerns for adopting best practice strategies. In Section 3, a sampling of builders participated in a telephone interview to gain baseline knowledge on insulation systems used to meet the current energy code and how the same builders intend to meet the new proposed code. In general, most builders expressed interest in being able to deliver greater energy efficiency to their customers. Concerns were voiced, however, about the costs compared to the energy savings, constructability, and durability risk resulting from increased foundation insulation R-values. When solutions for building robust foundation wall systems were presented to stakeholders, they did express interest in learning the details of the strategies. There was, however, continued interest in proof of cost, payback, and hygrothermal performance. Builders who participated in the interview were more confident in being able to meet the new requirements. This might have been a result of these respondents already using more advanced techniques for foundation insulation. This insight gives Building America an opportunity to engage the industry with existing research and practice measures that can address constructability and durability concerns at the proposed code levels. It also indicates that builders are interested in more specific information on cost, energy savings, and overall hygrothermal performance. Filling these voids could yield the supportive data needed to enhance building industry confidence and engage more states in the adoption of 2012 International Energy Conservation Code for new homes.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

Expert Meeting Report: Windows Options for New and Existing Homes

The NorthernSTAR Building America Partnership held an Expert Meeting on Windows Options for New and Existing Homes on November 14, 2011 at the Nolte Building on the campus of the University of Minnesota in Minneapolis, MN. Featured speakers included John Carmody and Pat Huelman of the University of Minnesota, Charlie Curcija of Lawrence Berkeley National Laboratory, Jim Larson of Cardinal Glass Industries, Peter Yost of Building Green, Peter Baker of Building Science Corporation, and Theresa Weston of Du Pont Innovations. Audience participation was actively encouraged during each presentation to uncover need and promote dialog among researchers and industry professionals.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

Determining Optimal Performance in Adapting Onsite Electrical Generation Platforms to Operate on Producer Gas from Fuels of Opportunity

The University of Minnesota is pleased to submit the final report for “Determining the Optimal Performance in Adapting Onsite Electrical Generation Platforms to Operate on producer Gas from Fuels of Opportunity, Concept Definition through Technology Development.” The University of Minnesota Morris campus was selected for this study primarily due to the advanced work the Morris campus has done in developing local fuels as a replacement for conventional fossil fuel supplies. Morris collaborated within the U of MN organization to bring the best research capabilities to the project. In addition, a core group of leading private partners was brought into the project based on their knowledge and expertise in portable energy platforms. The following report will illustrate the design and development process of comparing a nonconventional stationary biofueled combined heat and power plant with the state of the art biofueled portable internal combustion generator. The common denominator in this comparison is the focus on fuels of opportunity, which in this case is locally grown corn cobs. Both platforms used local sustainable fuel supplies to conduct the research and measure the outcomes.

09 BIOMASS FUELS↗
DOE OSTI2014

Charging and Heating Dynamics of Nanoparticles in Nonthermal Plasmas

The focus of this award was to understand the interactions of nanometer-sized particles with ionized gases, also called plasmas. Plasmas are widely used in the fabrication of electronic circuits such as microprocessors and memory devices, in plasma display panels, as well as in medical applications. Recently, these ionized gases are finding applications in the synthesis of advanced nanomaterials with novel properties, which are based on nanometer-sized particulate (nanoparticles) building blocks. As these nanoparticles grow in the plasma environment, they interact with the plasmas species such as electrons and ions which critically determines the nanoparticle properties. The University of Minnesota researchers conducting this project performed numerical simulations and developed analytical models that described the interaction of plasma-bound nanoparticles with the plasma ions. The plasma ions bombard the nanoparticle surface with substantial energy, which can result in the rearrangement of the nanoparticles’ atoms, giving them often desirable structures at the atomic scale. Being able to tune the ion energies allows to control the properties of nanoparticles produced in order to tailor their attributes for certain applications. For instance, when used in high efficiency light emitting devices, nanoparticles produced under high fluxes of highly energetic ions may show superior light emission to particles produced under low fluxes of less energetic ions. The analytical models developed by the University of Minnesota researchers enable the research community to easily determine the energy of ions bombarding the nanoparticles. The researchers extensively tested the validity of the analytical models by comparing them to sophisticated computer simulations based on stochastic particle modeling, also called Monte Carlo modeling, which simulated the motion of hundreds of thousands of ions and their interaction with the nanoparticle surfaces. Beyond the scientific intellectual merits, this award had significant broader impacts. Two graduate students received their doctoral degrees and both have joined a U.S. manufacturer of plasma-based semiconductor processing equipment. Four undergraduate students participated in research conducted under this grant and gained valuable hands-on laboratory experience. A middle school science teacher observed research conducted under this grant and developed three new course modules that introduce middle school students to the concepts of nanometer scale, the atomic structure of matter, and the composition of matter of different chemical elements.

42 ENGINEERING↗
DOE OSTI2013

Assessing Foundation Insulation Strategies for the 2012 International Energy Conservation Code in Cold Climate New Home Construction

While the International Energy Conservation Code 2012 (IECC 2012) has been adopted at a national level, only two cold climate states have adopted it as their new home energy code. Understanding the resistance to adoption is important in assisting more states accept the code and engage deep energy strategies nationwide. This three-part assessment by the NorthernSTAR Building America Partnership was focused on foundation insulation R-values for cold climates and the design, construction, and performance implications. In Part 1 a literature review and attendance at stakeholder meetings held in Minnesota were used to assess general stakeholder interest and concerns regarding proposed code changes. Part 2 includes drawings of robust foundation insulation systems that were presented at one Minnesota stakeholder meeting to address critical issues and concerns for adopting best practice strategies. In Part 3 a sampling of builders participated in a telephone interview to gain baseline knowledge on insulation systems used to meet the current energy code and how the same builders propose to meet the new proposed code.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

Expert Meeting Report: Windows Options for New and Existing Homes

The NorthernSTAR Building America Partnership held an Expert Meeting on Windows Options for New and Existing Homes on November 14, 2011, at the Nolte Building on the campus of the University of Minnesota in Minneapolis, MN. Featured speakers included John Carmody and Pat Huelman of the University of Minnesota, Charlie Curcija of Lawrence Berkeley National Laboratory, Jim Larson of Cardinal Glass Industries, Peter Yost of Building Green, Peter Baker of Building Science Corporation, and Theresa Weston of Du Pont Innovations. Audience participation was actively encouraged during each presentation to uncover need and promote dialog among researchers and industry professionals.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗