Advanced surface treatments for medium-velocity superconducting cavities for high-accelerating gradient continuous-wave operation
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McGee, K. (ORCID:0000000340572778)↗
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Results for “Michigan”
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Gamma-ray imaging of Np-237 metal using an organic glass imager
Neutron and gamma-ray imaging systems are deployed within the field of nuclear safeguards for the detection and localization of special nuclear materials and other materials of interest. 237 Np is one of these materials of interest due its presence in spent nuclear fuel and potential for use in nuclear weapons when purified. Here, for the first time, a 6 kg neptunium sphere (98.8 wt% 237 Np) was measured using a dual-particle imager, from the University of Michigan, consisting of organic glass and inorganic scintillators. The novel composition of organic glass scintillator was recently developed at Sandia National Labs and has been used in particle imaging systems due to its time resolution and particle discrimination capabilities. Gamma-ray energy spectra from single and coincident events were extracted and the sequencing of Compton scatter and photoelectric absorption gamma-ray events was used to generate images using simple backprojection. The emissions of interest in this work are the 312 keV and 416 keV gamma rays from 233 Pa, a daughter isotope from the neptunium decay series. The results of this work show that there is close agreement between the true source location in angular space and the converged location from the gamma ray images created using the system. The gamma spectroscopy from single and coincident events also identified the characteristic emission from the daughter isotope and could be used to assist with the identification of 237 Np. Furthermore, successful localization of the source with 5 s of data demonstrates the practical application of the imaging system for imaging and detection of material in weapons-useable quantities.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
3x3 array module of 8×8×32 mm 3 position-sensitive virtual frisch-grid CdZnTe detectors for imaging and spectroscopy of cosmic gamma-rays
Here, we evaluated the performance of the 3x3 array of 32-mm long position-sensitive virtual Frisch-grid (VFG) CdZnTe (CZT) detectors read out by the IDEAS GDS-100 data acquisition system. The array is a mechanically solid module designed for integration into a large effective area gamma-ray telescope proposed for imaging and spectroscopy of cosmic gamma-rays. The array employs the bar-shaped 8x8x32 mm 3 CZT crystals which recently became available from Redlen Technologies, Inc. and Kromek-eV Group PLC at affordable costs. The waveform sampling IDE3421 application-specific integrated circuit (ASIC), developed by the University of Michigan and IDEAS for CZT pixel detectors, was adapted to capture the signals from the array's VFG detectors. We showed good spectral performance of the Redlen detectors with an energy resolution of <1% FWHM at 662 keV and slightly poorer performance of the Kromek-eV detectors with a resolution of <2% measured at a reduced temperature of 13 °C. By testing the same detectors as single devices using hybrid charge-sensitive preamplifiers, we demonstrated improved energy resolutions at a normal temperature of ~25°C: <1% and 1.3-1.7%, respectively. However, the Kromek-eV detectors did not perform as well as the Redlen ones. We explained this by the space charge formation (polarization) decreasing the electric field and the electron drift times. The polarization was likely caused by the high injections of holes from the anode contacts. The absence of polarization in Redlen detectors suggested that the quality of the contacts might have played a role in this case.
47 OTHER INSTRUMENTATION↗
Commissioning of the Advanced Rare Isotope Separator ARIS at FRIB
The Facility for Rare Isotope Beams (FRIB) at Michigan State University (MSU) consists of a newly constructed linear accelerator and fragment separator that are designed for enhanced production rates of rare isotopes for use in research and other societal applications. Recent activities through to August 2022 took place to commission the Advanced Rare Isotope Separator (ARIS) and carry out the first experiments. This followed commissioning of the newly constructed linac that is designed to provide orders of magnitude higher beam power than the previously coupled cyclotrons. This required that more advanced target, beam dump, and collimation systems of the new separator be designed and constructed to sustain unprecedented conditions by heavy ion beams. Commissioning with ~1 kW beams began recently and results from activities that began in late 2021 are reported here. Comparisons between the previous and current facilities are provided.
43 PARTICLE ACCELERATORS↗
Gas stopping and reacceleration techniques at the Facility for Rare Isotope Beams (FRIB)
The Facility for Rare Isotope Beams (FRIB) at Michigan State University provides a wide range of beams and energies for science with fast, stopped and reaccelerated rare-isotope beams. FRIB was commissioned in 2022 with the science program beginning in May 2022. Here, the combination of fast beams followed by gas stopping of rare-isotope beams together with reacceleration is unique to FRIB. Stopping techniques and beam manipulation at very-low energies are important to slow down fast beams for use in either stopped-beam experimental devices, or subsequent injection in the reaccelerator for experiments at energies ranging from 0.3 MeV/u to 12 MeV/u, depending on the Q/A of the ion. Innovative stopped-beam techniques to optimize the stopping and extraction efficiencies across a wide range of atomic numbers, as well as to reduce contamination and increase extraction speed, were developed. Reacceleration of those beams involve cooling, bunching, charge breeding and acceleration by a state-of-the-art superconducting reaccelerator, ReA. In this contribution we present the latest results of various gas stoppers and techniques to eliminate contaminants after reacceleration by the ReA.
43 PARTICLE ACCELERATORS↗
The new Batch Mode Ion Source for stand-alone operation at the Facility for Rare Isotope Beams (FRIB)
Gas stoppers have been used for a long-standing successful science program at Michigan State University with stopped and rare-isotope beams produced by projectile fragmentation. The National Superconducting Cyclotron Laboratory’s Coupled Cyclotron Facility has recently transitioned into the Facility for Rare Isotope Beams (FRIB) laboratory to provide rare isotopes using a high-power superconducting linear accelerator and new production facilities. To allow the science program with stopped and reaccelerated beams to continue during the transition period, a stand-alone capability was added. The Batch Mode Ion Source (BMIS) was built and has been providing beams of long-lived and stable isotopes of a variety of elements for successful user experiments. Finally, the BMIS system is described and results from the production of various beams are presented.
47 OTHER INSTRUMENTATION↗
A dual dynamic shutter system for accelerating ion irradiation sample throughput via lateral gas implantation gradients
Ion irradiation for material performance testing is limited due to its serial nature, which allows for only one value of the implantation (appm) versus dose (dpa) parameter space to be explored for each ion and experiment at a time. While ion irradiation can accelerate the process by up to three orders of magnitude compared to neutron irradiation experiments, the sample throughput for ion irradiation remains relatively low. To address these limitations, a novel capability has been developed at the Michigan Ion Beam Laboratory (MIBL), enabling for the creation of single- and two-dimensional lateral ion implantation gradients using recently installed motorized-controlled ion-beam shutters. This advancement can generate a wide scope of the two-dimensional (H+, He2+) implantation parameter space within a single sample. Integration of this new capability now allows for dual- and triple-ion beam experiments to be performed with full user control over not only the ion implantation depth, but also laterally across the sample by imposing ion implantation concentration gradients, thus providing researchers with a high-throughput means for material testing under various irradiation conditions. Furthermore, recent improvements in MIBL's microbeam ion-beam analysis (IBA) target station now allow for probing these concentration gradients in irradiated alloys with exceptional spatial resolution, down to 10 µm. These two approaches promise to significantly improve ion irradiation capabilities and increase the sample throughput by several orders of magnitude. The application of the shutter technique plus the subsequent microbeam characterization of the imposed implantation gradients are showcased by two proof-of-principle ion-irradiated experiments, one performed on single-crystal Si and the other on the fusion-candidate alloy F82H-IEA. These advancements mark a substantial leap in ion-beam technology, offering researchers a robust, high-throughput method to efficiently investigate candidate alloys with high technological readiness for both advanced fission and fusion reactor applications, in a time- and cost-effective manner.
36 - MATERIALS SCIENCE↗
Total absorption spectroscopy measurement on neutron-rich 74,75 Cu isotopes
This paper reports on the first β-decay study of 74,75 Cu isotopes using the technique of total absorption spectroscopy (TAS). The experiment was performed at the National Superconducting Cyclotron Laboratory at Michigan State University using the Summing NaI(Tl) (SuN) detector. The Cu isotopes are good candidates to probe the single-particle structure in the region because they have one proton outside the Z = 28 shell. Comparing the β-decay intensity distributions in the daughter Zn isotopes to the theoretical predictions provides a stringent test of the calculations. The nuclei in this region are also identified as playing an important role in the astrophysical r-process. Furthermore, the measured β-decay intensity distributions provide essential nuclear physics inputs required to better understand heavy element nucleosynthesis.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Influence of turbulence intensity on vortex pattern for a rigid cylinder with turbulence stimulation in flow induced oscillations
The effect of ambient turbulence intensity on the flow induced oscillations of rigid circular cylinders with symmetric and asymmetric local turbulence stimulation is studied. Cylinders oscillate in one degree of freedom transversely to a steady uniform flow. Two-dimensional unsteady Reynolds-Average Navier-Stokes equations with the Spalart-Allmaras turbulence model are used to solve the problem numerically. Three freestream turbulence intensity values (0.2%, 1%, 5%) are used to study the influence of turbulence intensity on vortex pattern. Simulation results are compared with experimental data measured in the Marine Renewable Energy Laboratory of the University of Michigan in the range of 30,000 ≤ Re ≤ 110,000. The amplitude ratio, lift coefficient, vortex modes, and the interactions between vortices and cylinders are observed and discussed. In conclusion, major conclusions are: (a) Vortex patterns strongly depend on the freestream ambient turbulence intensity. (b) Low turbulence intensity can generate multi-vortex patterns at high Re. (c) High turbulence intensity results in fewer separations of a shed vortex into multiple vortices inducing emergence of elongated vortex patterns.
42 ENGINEERING↗
Secondary porosity prediction in complex carbonate reefs using 3D CT scan image analysis and machine learning
Development and preservation of carbonate porosity and permeability are critical to characterizing reservoirs. However, secondary porosity, such as vugs and fractures, are difficult to identify and require collection of expensive wireline tools or core sampling. Wireline logs and cores have traditionally been used to identify the presence of secondary porosity but fail to quantify the contribution to total reservoir porosity. Additionally, advanced wireline logs and core are not readily available for most wells. Dual energy CT scans were collected on whole core from the A-1 Carbonate and Brown Niagaran formations drawn from six wells in northern Michigan. 3D analysis techniques were applied to identify and isolate secondary porosity features. A series of machine learning and data analytics techniques were applied to the dataset to predict secondary porosity features on basic wireline logs. The predictive model successfully predicted secondary porosity with high confidence.
02 PETROLEUM↗
Hydrokinetic energy harvesting from slow currents using flow-induced oscillations
To harness marine hydrokinetic energy from slow flows, which constitute the majority of currents, tides, and rivers, new Passive Turbulence Control (PTC), consisting of large turbulence stimulators, is tested experimentally on circular cylinders on springs. Here, this study experimentally investigates the effect of PTC on the onset of Flow-Induced Oscillations (FIO) and particularly the relative onset of Vortex-Induced Vibrations (VIV) and galloping. Experiments are conducted in the Low Turbulence Free Surface Water Channel, University of Michigan. Fixed are: mass ratio m* = 1.48, aspect ratio l/D = 10.29, and total damping ratio ζ = 0.04. Parameters are: cylinder diameter D, spring stiffness K, PTC location and height, and flow speed U$\in$[0.36 m/s-1.45 m/s]. Placing the leading edge of PTC at 40–60° induces high amplitude FIO while placement at 10–20° suppresses FIO. As PTC height increases, VIV and galloping initiate earlier and exhibit higher amplitude with a steeper slope. Lower spring stiffness initiates VIV earlier by reducing the oscillator natural frequency in water. Even though large PTC maintained its effectiveness in initiating galloping early, it has no effect on the earlier initiation of VIV, which starts at a nearly fixed reduced velocity. Lower spring stiffness and large PTC enable power generation at low current speed (0.2 m/s).
16 TIDAL AND WAVE POWER↗
COVID-19 pandemic underscores role of green space in urban carbon dynamics
For Detroit Michigan the arrival of COVID-19 led to intensive measures to prevent further spread of the virus resulting in consequent changes in traffic and energy use. Here, we take advantage of these different emission scenarios to explore CO 2 dynamics in a postindustrial city with a declining population and increasing green space. We present atmospheric CO 2 concentration and net urban ecosystem exchange of CO 2 (NUE) from a typical eddy covariance system and canopy greenness from a field camera on the Wayne State University campus in midtown Detroit. We categorized our study period (January 18, 2020–July 31, 2020) into three subperiods associated with the state-wide shelter-in-place order. Our results support that the city was a net carbon source throughout the period, particularly during the shelter-in-place period, although reduced traffic lowered CO 2 concentrations and NUE. However, during the post-order period when traffic was highest, atmospheric CO 2 concentrations and NUE were lowest, suggesting that the greening of urban vegetation may have greater carbon mitigation potential than lowering anthropogenic carbon emissions through traffic reductions.
54 ENVIRONMENTAL SCIENCES↗
Root exudates shift how N mineralization and N fixation contribute to the plant-available N supply in low fertility soils
Nitrogen (N) availability is a primary constraint to plant productivity, especially in marginal lands with inherently low fertility. Root exudates change with plant nutrient status, and are expected to affect the microbially-mediated N transformations (gross N mineralization vs N fixation) in low fertility soil (low soil organic matter). To explore this possibility, we sampled soils from two monoculture switchgrass (var. Cave-In-Rock) plot with and without N addition at two marginal land sites in Michigan, USA. In a two-week lab incubation, we quantified the effect of different root exudates on gross N mineralization and N fixation by adding simulated root exudates (carbohydrates, organic acids) at a rate of 100 μg C g –1 day –1 . On average, adding carbohydrates to low fertility soil increased the soil respiration by 254%, the dissolved organic carbon (DOC) by 366% and reduced dissolved organic N (DON) by 40%. In contrast, soils receiving organic acids had 159% more soil respiration, 163% higher DOC concentration and the DON concentration increased by 49%. Analysis of the C recovery in measured pools revealed that root exudates C inputs were nearly equivalent to the DOC, microbial biomass carbon (MBC), and soil respiration in sandy soil, but only 45–74% of the root exudate C was recovered in these pools in the sandy loam soil. This suggests that root exudate C may be adsorbed to mineral particles in the sandy loam soil. Soil treated with organic acids had higher gross N mineralization and N immobilization rates than soil with carbohydrates addition. Adding carbohydrates significantly increased the free-living N fixation rates, compared to organic acid addition. Changes in soil pH, and DON induced by root exudate addition had strong association with N transformation rates and N availability. Gross N mineralization produced more plant-available N than N fixation, as evidenced by higher inorganic N concentration in soils receiving organic acids than carbohydrates. Here, by quantifying how different root exudates affect the contribution of N mineralization and N fixation to the plant-available N pool in low fertility soils, this study enhances our understanding of the “C for N” exchange in the plant rhizosphere.
54 ENVIRONMENTAL SCIENCES↗
Chemical identity of carbon substrates drives differences in denitrification and N 2 O reduction within agricultural soils
Rates of nitrous oxide (N 2 O) production from agricultural soils are highly variable across space and time. Improving predictions of N 2 O emissions will require improving our understanding of the drivers of denitrification and the sources of variability in the rates of N 2 O production between soils and over time. While the amount of available carbon (C) is a known control on denitrification and N 2 O reduction, relatively little attention has been paid to the effect of the chemical identity of C substrates on rates of denitrification and N 2 O reduction. We investigated the effects of twelve different C-substrate additions on the production and reduction of N 2 O in five soils taken from two distinct agricultural locations in Michigan under multiple land uses. We provided additions of glucose, cellulose, N-acetyl-glucosamine, chitin, amino acids, protein, vanillyl alcohol, lignin, citrate, succinate, methanol, and water in laboratory denitrification potential assays to determine the effects of denitrifier C preference on denitrification rates. We found that amino acids, protein, and organic acids stimulated the greatest rates of denitrification potential across all land uses. Similarly, we found these same substrates caused the most N 2 O reduction, resulting in the lowest net concentrations of N 2 O. Soils from agricultural rotations without cover crops had overall lower rates of denitrifier activity, leading to less net N 2 O production compared to soils from other land uses. In general, C-utilization patterns were similar among all soils, and C-substrate identity had a much stronger effect than land use. Here, we demonstrate that the chemical identity of available C gives rise to wide variability in rates of denitrification and N 2 O reduction.
60 APPLIED LIFE SCIENCES↗
Refueling infrastructure planning in intercity networks considering route choice and travel time delay for mixed fleet of electric and conventional vehicles
The range anxiety has been a major factor that affects the market acceptance of electric vehicles. Even with the recent development of battery technologies, a lack of charging stations and range anxiety are still significant concerns, specifically for intercity trips. This calls for more investments in building charging stations and advancing battery technologies to increase the market share of electric vehicles and improve sustainability. This study suggests a configuration for plug-in electric vehicle charging infrastructure to support long-distance intercity trips of electric vehicles at the network level. A model is proposed to minimize the total system cost including infrastructure investment (building charging stations/spots) and travel time delays (charging time, waiting time in the queue, and detour time to access charging stations). This study fills existing gaps in the literature by capturing realistic patterns of travel demand and considering flow-dependent charging delays at charging stations. Furthermore, the proposed model, which is formulated as a mixed-integer program with nonlinear constraints, solves the optimization problem at the network level. At the network level, impacts of charging station locations on the traffic assignment problem with a mixed fleet of electric and conventional vehicles need to be considered. To this end, a traffic assignment module is integrated with a simulated annealing algorithm. The numerical experiments show a satisfactory application of the model for a full-scale case study (intercity network in Michigan). The solution quality and efficiency of the proposed solution algorithm are evaluated against those of an enumeration approach for a small case study. The results suggest that even for the current market share and charging stations’ setting, a significant investment is needed to support intercity trips without range anxiety issues and with acceptable delays. Additionally, through sensitivity analyses, the required infrastructure and battery investments to support intercity trips with acceptable delays are established for hypothetical increased market shares and battery size in the future.
42 ENGINEERING↗
Contrasting effects of lake breeze and urbanization on heat stress in Chicago metropolitan area
This study used the latest Weather Research and Forecasting (WRF) model coupled with multi -layer urban canopy models to investigate contrasting effects from urbanization and lake breeze on summer heat stress over the Chicago metropolitan area (CMA). Comparisons between the model and in situ observations show that this coupled modeling system better captures urban locations' diurnal pattern of surface air temperature, skin temperature and relative humidity, with root mean square error reduced from 1.58 to 1.80 degrees C to 1.14-1.31 degrees C, 3.11-3.55 degrees C to 1.81-2.21 degrees C, and 10.73-11.35% to 7.84-8.60%, respectively, compared to WRF without coupling the urban canopy models. Two sensitivity experiments were conducted to isolate the influence of lake breeze and urbanization: one replaced the urban land use with cropland over the CMA, and the other filled all of Lake Michigan with cropland. Three different heat stress indices were computed to assess the uncertainties of heat stress response to changes in air temperature, relative humidity, and wind conditions. Results show that, when the lake has the largest cooling effect on air temperature, it also increases the relative humidity the most, and vice versa for urban warming and drying effects. Urbanization intensifies heat stress at night, and extends the heat caution period by up to 4 h over inland urban grids; the lake breeze relieves heat stress during afternoon (when the heat stress is the worst), and shortens the heat caution period by 1-3 h over inland urban grids and 3-4 h over coastal urban grids. In conclusion, the intensification of heat stress over the CMA due to urbanization is more than four times greater than the reduction from the lake breeze in the late afternoon and evening.
54 ENVIRONMENTAL SCIENCES↗
Biogeochemistry of the Antrim Shale Natural Gas Reservoir
The Antrim Shale, located in the Michigan Basin, United States (U.S.), is a major U.S. shale play having produced over 2.5 Trillion Cubic Feet (Tcf) of unconventional shale natural gas as of 2010. The shallow nature of this formation sets it apart from other, more characterized unconventional shale gas plays. The depth of gas production of the Antrim ranges from approximately 150 to 600 m and it is typically vertically drilled, contrary to deeper, horizontally drilled shales. A thorough understanding of the biogeochemistry and microbiology of this complex system will be advantageous for improving well performance, produced water management, and potential biocidal treatment as microbial community composition can vary substantially even among closely spaced wells. In this study, we analyzed produced water collected from nine different wells in the Antrim Shale by investigating the geochemical and microbial community composition of the produced water to gain greater insight into the overall biogeochemistry of this unique shale system. The majority of the wells from this study had high total dissolved solids (TDS) primarily composed of chloride and sodium, averaging 86,804 mg/L with a maximum 116,223 mg/L; however, three of the wells sampled along the northern margin of the basin exhibited significantly lower TDS ranging from 4932 to 6496 mg/L. Overall, our microbial community analysis revealed relatively low abundance within our samples and high variability of the microbial community among the sampled wells. The majority of bacterial sequences were identified within Proteobacteria, Firmicutes, and Actinobacteria phyla and metagenomic sequencing revealed the low presence of Methanobacteriaceae within each sample. We also investigated potential microbial community drivers and found that TDS, sodium, chloride, iodide, bromide, ammonium, potassium, and strontium were significantly correlated with the observed microbial community. The varying geochemical conditions between wells demonstrate different subsurface environmental niches, potentially driving the heterogeneous microbial communities we observed from well to well. This analysis suggests an important relationship between both well location and geochemistry and the observed microbial community that can persist in the reservoir. Continued studies of the Antrim Shale will improve our understanding of the complex interdependencies of this ecosystem.
03 NATURAL GAS↗
Quantifying the Contributions of Aerosol- and Snow-Produced ClNO 2 through Observations and 1D Modeling
Nitryl chloride (ClNO 2 ) is a radical reservoir that forms and accumulates in the nocturnal atmospheric boundary layer influenced by combustion emissions and chloride (e.g., sea salt and road salt). Upon sunrise, ClNO 2 rapidly photolyzes to generate highly reactive chlorine radicals (Cl • ) that affect the air quality by generating secondary air pollutants. Recent studies have shown road salt aerosols and saline snowpack to be sources of ClNO 2 in the wintertime urban environment; however, the quantitative contributions of each chloride source are not known. In this study, we examine the vertically resolved contributions of aerosol particles and saline snowpack as sources of ClNO 2 by using an observationally constrained snow–atmosphere coupled one-dimensional model applied to wintertime Kalamazoo, Michigan, U.S. Model simulations show that ClNO 2 emitted from urban snowpack can be vertically transported throughout the entire atmospheric boundary layer and can be a significant source of ClNO 2 , contributing up to ~60% of the ClNO 2 budget near the surface. Here, modeled snowpack ClNO 2 emission rates were 6 (±7) times higher than the observationally derived emission rates, suggesting that not all snow chloride is available for reaction. ClNO 2 production from both aerosol particles and snow emissions are required to best simulate the observed surface-level ClNO 2 . Using the traditional bulk parameterization for ClNO 2 produced from particles significantly overestimated ClNO 2 due to the assumption of having equivalent dinitrogen pentoxide (N 2 O 5 ) uptake and chloride availability for the entire particle population. In comparison, the chemically resolved surface area-based parameterization slightly underestimated the observations and had uncertainties deriving from ClNO 2 production from residential wood burning particles.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗