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All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Aerosol Influences on Cloud Water: Insights From ARM EPCAPE Observations With Explainable Machine Learning

This study employs an explainable machine learning (ML) framework (XGBoost-SHapley Additive exPlanations analysis) to investigate controlling factors on cloud liquid water path (LWP) using EPCAPE observations near the California coast. Aerosols are found to be the dominant factor explaining LWP variability, surpassing meteorological factors (MFs). By isolating aerosol effects from meteorological influences, the ML reveals a negative linear relationship between LWP and cloud droplet number concentration (Nd) in log space, likely driven by entrainment drying via evaporation-entrainment feedback. This aligns with the negative regime of the inverted-V relationship reported in previous studies, while no positive LWP responses are found due to a limited number of precipitating cases in EPCAPE. Furthermore, the sensitivity of LWP to Nd shows a non-linear dependence on MFs like moisture contrast between surface and free troposphere and lower-tropospheric stability. This occurs due to the interplay between the MFs' direct effects on entrainment drying and indirect effects through LWP adjustments.

EPCAPE observations↗
DOE OSTI2023

Finalizing Transition to the New Data Center at BNL

Computational science, data management and analysis have been key factors in the success of Brookhaven National Laboratory's scientific programs at the Relativistic Heavy Ion Collider (RHIC), the National Synchrotron Light Source (NSLS-II), the Center for Functional Nanomaterials (CFN), and in biological, atmospheric, and energy systems science, Lattice Quantum Chromodynamics (LQCD) and Materials Science, as well as our participation in international research collaborations, such as the ATLAS Experiment at Europe's Large Hadron Collider (LHC) at CERN (Switzerland) and the Belle II Experiment at KEK (Japan). The construction of a new data center is an acknowledgement of the increasing demand for computing and storage services at BNL in the near term and enable the Lab to address the needs of the future experiments at the High-Luminosity LHC at CERN and the Electron-Ion Collider (EIC) at BNL in the long term. The Computing Facility Revitalization (CFR) project is aimed at repurposing the former National Synchrotron Light Source (NSLS-I) building as the new data center for BNL. The construction of the new data center was finished in 2021Q3, and it was delivered for production in early FY2022 for all collaborations supported by the Scientific Data and Computing Center (SDCC), including STAR, PHENIX and sPHENIX experiments at RHIC collider at BNL, the Belle II Experiment at KEK (Japan), and the Computational Science Initiative at BNL (CSI). This paper highlights the key mechanical, electrical, and networking components of the new data center in its final configuration as used in production since 2021Q4 and gives an overview for the extension of the central network systems into the new data center and the migration of a significant portion of IT load and services from the old data center to the new data center carried out in 20212023, with expected completion of the main phase of the gradual IT equipment replacement and migration from the old data center into the new one set to the end of FY2023 (Sep 30, 2023).

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2019

Residual Stress and Opening-Mode Fracture Analysis of Multilayered Structures Subjected to Thermal Loading

Temperature change after formation commonly results in thermal residual stress in multilayered structures due to the different thermal and mechanical properties of each layer. In this paper, a three-dimensional (3D) elastic model is developed to study the residual stress and opening-mode fractures (OMFs) in a multilayered structure consisting of arbitrary number of layers under temperature change. The general solution of displacement field in the multilayered structure is derived by solving the elastic boundary value problem. In order to verify the proposed model, the elastic field in the advanced polymeric solar reflectors that consist of four layers is solved by applying the present model and compared with the finite-element (FE) simulation. In addition, parametric studies are conducted to investigate the effect of the thickness ratio between each layer on the accuracy of the developed model. As a result, based on the obtained elastic field, the fracture energy release rate (ERR) in the surface layer of the advanced polymeric reflector is obtained and used to study the fracture initiation, infilling, and saturation successfully.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Conductivity space isotherm behavior in quantum anomalous Hall devices

The quantum Hall effect (QHE) has enhanced accessibility to measure and disseminate electrical units, owed in part to the recently redefined International System of Units in 2019. Graphene remains one of the preferred options to realize the ohm despite the limitations of high magnetic fields to produce a robust QHE. Topological insulators, on the other hand, show promise in providing quantized resistance via the quantum anomalous Hall effect, a phenomenon that removes the need for magnetic fields during operation. To optimize future devices for metrological applications, it is important to gain a better understanding of magnetically doped topological insulators like Cr-doped bismuth antimony telluride. The application of differential conductivity space analyses offers a more sensitive way to analyze the data and distinguish between 2D and 3D transport behaviors. This is particularly important in thin films, where the transition between 2D and 3D behavior can be subtle. The ability to confidently determine the dimensionality of the transport is crucial for selecting appropriate theoretical models for future device optimization. Furthermore, this work identifies variable range hopping as the dominant transport mechanism in the 2D regime using a rigorous statistical analysis (via the Bayes factor). These elements assist in the understanding of microscopic processes that govern charge transport in these materials.

Tran, N. T. M. [National Inst. of Standards and Te↗
DOE OSTI2024

Insights on seasonal solifluction processes in warm permafrost Arctic landscape using a dense monitoring approach across adjacent hillslopes

Solifluction processes in the Arctic are highly complex, introducing uncertainties in estimating current and future soil carbon storage and fluxes, and assessment of hillslope and infrastructure stability. This study aims to enhance our understanding of triggers and drivers of soil movement of permafrost-affected hillslopes in the Arctic. To achieve this, we established an extensive soil deformation and temperature sensor network, covering 48 locations across multiple hillslopes within a 1 km² watershed on the Seward Peninsula, AK. We report depth-resolved measurements down to 1.8 m depth for May to September 2022, a period conducive to soil movement due to deepening thaw layers and frequent rain events. Over this period, surface movements of up to 334 mm were recorded. In general, these movements occur close to the thawing front, and are initiated as thawing reaches depths of 0.4 to 0.75 m. The largest movements were observed at the top of the south-east facing slope, where soil temperatures are cold (mean annual soil temperatures averaging -1.13°C) and slopes are steeper than 15°. Our analysis highlights three primary factors influencing movements: slope angle, soil thermal conditions, and thaw depth. The latter two significantly impact the generation of pore water pressures at the thaw–freeze interface. Specifically, soil thermal conditions govern the liquid water content, while thaw depth influences both the height of the water column and, consequently, the pressure at the thawing front. These factors affect soil properties, such as cohesion and internal friction angle, which are crucial determinants of slope stability. This underscores the significance of a precise understanding of subsurface thermal conditions, including spatial and temporal variability in soil temperature and thaw depth, when assessing and predicting slope instabilities. Based on our observations, we developed a Factor of Safety proxy that consistently falls below the triggering threshold for all probes exhibiting displacements exceeding 50 mm. This study offers novel insights into patterns and triggers of hillslope movements in the Arctic and provides a venue to evaluate their impact on soil redistribution.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Rubisco regulation in response to altered carbon status in the cyanobacterium Synechococcus elongatus PCC 7942

Abstract Photosynthetic organisms possess a variety of mechanisms to achieve balance between absorbed light (source) and the capacity to metabolically utilize or dissipate this energy (sink). While regulatory processes that detect changes in metabolic status/balance are relatively well studied in plants, analogous pathways remain poorly characterized in photosynthetic microbes. Here, we explored systemic changes that result from alterations in carbon availability in the model cyanobacterium Synechococcus elongatus PCC 7942 by taking advantage of an engineered strain where influx/efflux of a central carbon metabolite, sucrose, can be regulated experimentally. We observed that induction of a high-flux sucrose export pathway leads to depletion of internal carbon storage pools (glycogen) and concurrent increases in estimates of photosynthetic activity. Further, a proteome-wide analysis and fluorescence reporter-based analysis revealed that upregulated factors following the activation of the metabolic sink are concentrated on ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco) and auxiliary modules involved in Rubisco maturation. Carboxysome number and Rubisco activity also increased following engagement of sucrose secretion. Conversely, reversing the flux of sucrose by feeding exogenous sucrose through the heterologous transporter resulted in increased glycogen pools, decreased Rubisco abundance, and carboxysome reorganization. Our data suggest that Rubisco activity and organization are key variables connected to regulatory pathways involved in metabolic balancing in cyanobacteria.

Plant Sciences↗
DOE OSTI2021

Cross-scale dynamics and the evolutionary emergence of infectious diseases

When emerging pathogens encounter new host species for which they are poorly adapted, they must evolve to escape extinction. Pathogens experience selection on traits at multiple scales, including replication rates within host individuals and transmissibility between hosts. We analyze a stochastic model linking pathogen growth and competition within individuals to transmission between individuals. Our analysis reveals a new factor, the cross-scale reproductive number of a mutant virion, that quantifies how quickly mutant strains increase in frequency when they initially appear in the infected host population. This cross-scale reproductive number combines with viral mutation rates, single-strain reproductive numbers, and transmission bottleneck width to determine the likelihood of evolutionary emergence, and whether evolution occurs swiftly or gradually within chains of transmission. We find that wider transmission bottlenecks facilitate emergence of pathogens with short-term infections, but hinder emergence of pathogens exhibiting cross-scale selective conflict and long-term infections. Furthermore, our results provide a framework to advance the integration of laboratory, clinical, and field data in the context of evolutionary theory, laying the foundation for a new generation of evidence-based risk assessment of emergence threats.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Transverse energy-energy correlators in the color-glass condensate at the electron-ion collider

We investigate the transverse energy-energy correlators (TEEC) in the small- x regime at the upcoming Electron-Ion Collider (EIC). Focusing on the back-to-back production of electron-hadron pairs in both e p and e A collisions, we establish a factorization formula given in terms of the hard function, quark distributions, soft functions, and TEEC jet functions, where the gluon saturation effect is incorporated. Numerical results for TEEC in both e p and e A collisions are presented, together with the nuclear modification factor R A . Our analysis reveals that TEEC observables in deep inelastic scattering provide a valuable approach for probing gluon saturation phenomena. Our findings underscore the significance of measuring TEEC at the EIC, emphasizing its efficacy in advancing our understanding of gluon saturation and nuclear modifications in high-energy collisions. Published by the American Physical Society 2024

Astronomy & Astrophysics↗
DOE OSTI2017

ECCI, EBSD and EPSC characterization of rhombohedral twinning in polycrystalline α-alumina deformed in a D-DIA apparatus

Rhombohedral twinning in alumina (aluminium oxide, α-Al 2 O 3 ) is an important mechanism for plastic deformation under high-temperature–pressure conditions. Rhombohedral twins in a polycrystalline alumina sample deformed in a D-DIA apparatus at 965 K and 4.48 GPa have been characterized. Three classes of grains were imaged, containing single, double and mosaic twins, using electron channeling contrast imaging (ECCI) in a field emission scanning electron microscope. These twinned grains were analyzed using electron backscatter diffraction (EBSD). The methodology for twin identification presented here is based on comparison of theoretical pole figures for a rhombohedral twin with experimental pole figures obtained with EBSD crystal orientation mapping. An 85°(02{\overline 2}1) angle–axis pair of misorientation was identified for rhombohedral twin boundaries in alumina, which can be readily used in EBSD post-processing software to identify the twin boundaries in EBSD maps and distinguish the rhombohedral twins from basal twins. Elastic plastic self-consistent (EPSC) modeling was then used to model the synchrotron X-ray diffraction data from the D-DIA experiments utilizing the rhombohedral twinning law. From these EPSC models, a critical resolved shear stress of 0.25 GPa was obtained for rhombohedral twinning under the above experimental conditions, which is internally consistent with the value estimated from the applied load and Schmid factors determined by EBSD analysis.

Kaboli, Shirin (ORCID:0000000307447764)↗
DOE OSTI2016

Comparison of CIGS solar cells made with different structures and fabrication techniques

Cu(In, Ga)Se2 (CIGS)-based solar cells from six fabricators were characterized and compared. The devices had differing substrates, absorber deposition processes, buffer materials, and contact materials. The effective bandgaps of devices varied from 1.05 to 1.22 eV, with the lowest optical bandgaps occurring in those with metal-precursor absorber processes. Devices with Zn(O, S) or thin CdS buffers had quantum efficiencies above 90% down to 400 nm. Most voltages were 250-300 mV below the Shockley-Queisser limit for their bandgap. Electroluminescence intensity tracked well with the respective voltage deficits. Fill factor (FF) was as high as 95% of the maximum for each device's respective current and voltage, with higher FF corresponding to lower diode quality factors (~1.3). An in-depth analysis of FF losses determined that diode quality reflected in the quality factor, voltage-dependent photocurrent, and, to a lesser extent, the parasitic resistances are the limiting factors. As a result, different absorber processes and device structures led to a range of electrical and physical characteristics, yet this investigation showed that multiple fabrication pathways could lead to high-quality and high-efficiency solar cells.

14 SOLAR ENERGY↗
DOE OSTI2023

Considering the Variability of Soiling in Long-Term PV Performance Forecasting

This study presents the development of a methodology for evaluating the variability associated with soiling on long-term photovoltaic (PV) forecasting. Independent engineering firms typically build forecasts for large PV plants through the use of the PVsyst software, where monthly soiling losses are one of many inputs to the P50 model. Subsequently, long-term performance distributions are constructed through a Monte Carlo analysis that includes various factors, such as satellite irradiance modeling uncertainty, uncertainty in the PVsyst model, and long-term irradiance variability. Often the PVsyst model uncertainty is increased to account for sites with significant soiling concerns but no systematic method has been presented in the literature to specifically include soiling variability within long-term performance uncertainty. In this work soiling information from 16 sites in the U.S. Southwest are combined with 24 years of rainfall data to generate 24 years of energy production with soiling losses and then subsequently generate probability of exceedance values (e.g., P50, P90, P95…). The results show that the size of the 90% confidence interval (P5–P95) can increase from –0.7% to 10.1% when interannual soiling variability and soiling rate uncertainty is included.

14 SOLAR ENERGY↗
DOE OSTI2018

Tree mycorrhizal type predicts within‐site variability in the storage and distribution of soil organic matter

Abstract Forest soils store large amounts of carbon (C) and nitrogen (N), yet how predicted shifts in forest composition will impact long‐term C and N persistence remains poorly understood. A recent hypothesis predicts that soils under trees associated with arbuscular mycorrhizas ( AM ) store less C than soils dominated by trees associated with ectomycorrhizas ( ECM ), due to slower decomposition in ECM ‐dominated forests. However, an incipient hypothesis predicts that systems with rapid decomposition—e.g. most AM ‐dominated forests—enhance soil organic matter ( SOM ) stabilization by accelerating the production of microbial residues. To address these contrasting predictions, we quantified soil C and N to 1 m depth across gradients of ECM ‐dominance in three temperate forests. By focusing on sites where AM ‐ and ECM ‐plants co‐occur, our analysis controls for climatic factors that covary with mycorrhizal dominance across broad scales. We found that while ECM stands contain more SOM in topsoil, AM stands contain more SOM when subsoil to 1 m depth is included. Biomarkers and soil fractionations reveal that these patterns are driven by an accumulation of microbial residues in AM ‐dominated soils. Collectively, our results support emerging theory on SOM formation, demonstrate the importance of subsurface soils in mediating plant effects on soil C and N, and indicate that shifts in the mycorrhizal composition of temperate forests may alter the stabilization of SOM .

Craig, Matthew E.↗
DOE OSTI2019

Experimental Investigation on Additively Manufactured Transpiration and Film Cooling Structures

The last 50 years has witnessed significant improvement in film cooling technologies while transpiration cooling is still not implemented in turbine airfoil cooling. Although transpiration cooling could provide higher cooling efficiency with less coolant consumption compared to film cooling, the fine pore structure and high porosity in transpiration cooling metal media always raised difficulties in conventional manufacturing. Recently, the rapid development of additive manufacturing (AM) has provided a new perspective to address such challenge. With the capability of the innovative powder bed selective laser metal sintering (SLMS) AM technology, the complex geometries of transpiration cooling part could be precisely fabricated and endued with improved mechanical strength. This study utilized the SLMS AM technology to fabricate the transpiration cooling and film cooling structures with Inconel 718 superalloy. Five different types of porous media including two perforated plates with different hole pitches, metal sphere packing, metal wire mesh, and blood vessel shaped passages for transpiration cooling were fabricated by EOS M290 system. One laidback fan-shaped film cooling coupon was also fabricated with the same printing process as the control group. Heat transfer tests under three different coolant mass flow rates and four different mainstream temperatures were conducted to evaluate the cooling performance of the printed coupons. The effects of geometry parameters including porosity, surface outlet area ratio, and internal solid–fluid interface area ratio were investigated as well. The results showed that the transpiration cooling structures generally had higher cooling effectiveness than film cooling structure. The overall average cooling effectiveness of blood vessel-shaped transpiration cooling reached 0.35, 0.5, and 0.57, respectively, with low (1.2%), medium (2.4%), and high (3.6%) coolant injection ratios. The morphological parameters analysis showed the major factor that affected the cooling effectiveness most was the internal solid–fluid interface area ratio for transpiration cooling. This study showed that additive manufactured transpiration cooling could be a promising alternative method for turbine blade cooling and worthwhile for further investigations.

Engineering↗
DOE OSTI2016

WE-H-BRC-04: Implement Lean Methodology to Make Our Current Process of CT Simulation to Treatment More Efficient

Purpose: Our goal is to implement lean methodology to make our current process of CT simulation to treatment more efficient. Methods: In this study, we implemented lean methodology and tools and employed flowchart in excel for process-mapping. We formed a group of physicians, physicists, dosimetrists, therapists and a clinical physics assistant and huddled bi-weekly to map current value streams. We performed GEMBA walks and observed current processes from scheduling patient CT Simulations to treatment plan approval. From this, the entire workflow was categorized into processes, sub-processes, and tasks. For each process we gathered data on touch time, first time quality, undesirable effects (UDEs), and wait-times from relevant members of each task. UDEs were binned per frequency of their occurrence. We huddled to map future state and to find solutions to high frequency UDEs. We implemented visual controls, hard stops, and documented issues found during chart checks prior to treatment plan approval. Results: We have identified approximately 64 UDEs in our current workflow that could cause delays, re-work, compromise the quality and safety of patient treatments, or cause wait times between 1 – 6 days. While some UDEs are unavoidable, such as re-planning due to patient weight loss, eliminating avoidable UDEs is our goal. In 2015, we found 399 issues with patient treatment plans, of which 261, 95 and 43 were low, medium and high severity, respectively. We also mapped patient-specific QA processes for IMRT/Rapid Arc and SRS/SBRT, involving 10 and 18 steps, respectively. From these, 13 UDEs were found and 5 were addressed that solved 20% of issues. Conclusion: We have successfully implemented lean methodology and tools. We are further mapping treatment site specific workflows to identify bottlenecks, potential breakdowns and personnel allocation and employ tools like failure mode effects analysis to mitigate risk factors to make this process efficient.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

USE OF COGNITIVE WORK ANALYSIS IN DEVELOPING A NUCLEAR POWER PLANT NEW STATE VISION

The United States nuclear industry is in need of identifying and implementing a new strategy that will lower operating and maintenance costs while maintaining safety for existing plants. The industry must also have a clear and strategic vision of their transformative new state that focuses on ways in which technologies can be integrated to maximize the benefits of technology and people. While there are ongoing efforts in this area, this work discusses how the use of cognitive work analysis may further support these current efforts. This paper provides an overview of cognitive work analysis, as well as the state of current new state development efforts. The use of cognitive work analysis, as a tool to enhance existing practices, is presented in ensuring that the development of a new state vision is systematic and complete.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2019

Cholangiographic Tumor Classification for Simple Patient Selection Prior to Hepatopancreatoduodenectomy for Cholangiocarcinoma

Background: Hepatopancreatoduodenectomy (HPD) is employed for patients with laterally advanced cholangiocarcinoma. However, the survival benefit of this extended approach remains controversial. The aim of this study is to identify a tumor feature benefiting from HPD from the standpoint of long-term survival. Patients and Methods: Patients with cholangiocarcinoma who underwent HPD with curative intent between 2001 and 2017 were retrospectively analyzed. Tumors were radiologically classified by preoperative cholangiogram. Diffuse type was defined as significant tumor/stricture located from the hilar to intrapancreatic duct; localized type was defined as tumor otherwise. Univariable and multivariable analyses were performed to identify prognostic indicators. Results: Of 100 study patients, 28 (28%) patients had diffuse tumor type, while the remaining 72 (72%) patients had localized tumors. The former group showed significantly longer lateral length (43 versus 22 mm, P < 0.001) and more frequent pancreatic invasion (50% versus 32%, P = 0.110), advanced T classification (64% versus 49%, P = 0.185), and nodal metastasis (57% versus 47%, P = 0.504), compared with the latter group. The survival for patients with diffuse tumor type was significantly worse than that for patients with localized tumor type, with 5-year survival rates of 59.0% versus 26.3%, respectively (P = 0.003). Multivariable analysis identified four independent factors deteriorating long-term survival: cholangiographic diffuse tumor (P = 0.021), higher age (P = 0.020), percutaneous biliary drainage (P = 0.007), and portal vein resection (P = 0.007). Conclusions: Presurgical cholangiographic classification, diffuse or localized type, is a tumor-related factor closely associated with survival probability; therefore, it may be a useful feature for patient selection prior to HPD for cholangiocarcinoma.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2025

Animal movement estimation and network-based epidemic modeling: Illustration for the swine industry in Iowa (US)

Animal movement plays a critical role in disease transmission between farms. However, in the United States, the lack of available animal shipment data, sometimes coupled with a lack of detailed information about farm demographics and characteristics, presents great challenges for epidemic modeling and prediction. In this study, we proposed a new method based on the maximum entropy to generate “synthetic” animal movement networks, considering available statistics about the premises operation type, operation size, and the distance between premises. We illustrated our method for the swine movement networks in Iowa and performed network analyses to gain insights into the swine industry. We then applied the generated networks to a network-based epidemic model to identify potential system vulnerabilities in terms of disease transmission. The model was parameterized for African Swine Fever (ASF) as the US swine industry is quite concerned about this disease. Results show that premises with a central role in the network are more vulnerable to disease outbreaks and play an important role in disease spread. Simulations with outbreaks starting from random farms reveal no significant large outbreaks, indicating the system’s relative robustness against arbitrary disease introductions. However, outbreaks originating from high out-degree farms can lead to large epidemic sizes. This underscores the importance for stakeholders and policymakers to continue improving animal movement records and traceability programs in the US and the value of making that data available to epidemiologists and modelers to better understand risk and inform strategies aimed to cost-effectively prevent and control disease transmission. Our approach could be easily adapted to estimate movement networks in other animal production systems and to inform disease spread models for various infectious diseases.

60 APPLIED LIFE SCIENCES↗