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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 271 records · Page 15

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DOE OSTI2016

SU-F-R-01: Preclinical Radioimmunogenomics Study to Design Personalized Radiotherapy

Purpose: Radiogenomics is an active area of research to find clinical correlation between genomics and radiotherapy outcomes. In this era, many different biological issues should be taken into account. In this study we aimed to introduce “Radioimmunogenomics” as a new approach to study immunogetics issue regard to radiotherapy induced clinical manifestations. Methods: We studied different immunological pathways and signaling molecules which underling radiation response of normal and malignant tissues. In the other hand, we found many genes and proteins are responsible to radiation effects on biological tissues. We defined a theoretical framework to correlate these genes with radiotherapy outcomes as TCP and NTCP biological dose tools. Results: Our theoretical results showed, high-throughput immunogenomics biomarkers can be correlated with radiotherapy outcomes. Genes regarding to inflammation, apoptosis, repair molecules and many other immunological markers can be defined as radioimmune markers to predict radiotherapy response. Conclusion: Radioimmunogenomics can be used as a new personalized radiotherapy research area to enhance treatment outcome as well as quality of life.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2025

Exponential Backoff and Its Security Implications for Safety-Critical OT Protocols over TCP/IP Networks

The convergence of Operational Technology (OT) and Information Technology (IT) networks has become increasingly prevalent with the growth of Industrial Internet of Things (IIoT) applications. This shift, while enabling enhanced automation, remote monitoring, and data sharing, also introduces new challenges related to communication latency and cybersecurity. Oftentimes, legacy OT protocols were adapted to the TCP/IP stack without an extensive review of the ramifications to their robustness, performance, or safety objectives. To further accommodate the IT/OT convergence, protocol gateways were introduced to facilitate the migration from serial protocols to TCP/IP protocol stacks within modern IT/OT infrastructure. However, they often introduce additional vulnerabilities by exposing traditionally isolated protocols to external threats. This study investigates the security and reliability implications of migrating serial protocols to TCP/IP stacks and the impact of protocol gateways, utilizing two widely used OT protocols: Modbus TCP and DNP3. Our protocol analysis finds a significant safety-critical vulnerability resulting from this migration, and our subsequent tests clearly demonstrate its presence and impact. A multi-tiered testbed, consisting of both physical and emulated components, is used to evaluate protocol performance and the effects of device-specific implementation flaws. Through this analysis of specifications and behaviors during communication interruptions, we identify critical differences in fault handling and the impact on time-sensitive data delivery. The findings highlight how reliance on lower-level IT protocols can undermine OT system resilience, and they inform the development of mitigation strategies to enhance the robustness of industrial communication networks.

DNP3↗

DOE OSTI2016

Measurements of file transfer rates over dedicated long-haul connections

Wide-area file transfers are an integral part of several High-Performance Computing (HPC) scenarios. Dedicated network connections with high capacity, low loss rate and low competing traffic, are increasingly being provisioned over current HPC infrastructures to support such transfers. To gain insights into these file transfers, we collected transfer rate measurements for Lustre and xfs file systems between dedicated multi-core servers over emulated 10 Gbps connections with round trip times (rtt) in 0-366 ms range. Memory transfer throughput over these connections is measured using iperf, and file IO throughput on host systems is measured using xddprof. We consider two file system configurations: Lustre over IB network and xfs over SSD connected to PCI bus. Files are transferred using xdd across these connections, and the transfer rates are measured, which indicate the need to jointly optimize the connection and host file IO parameters to achieve peak transfer rates. In particular, these measurements indicate that (i) peak file transfer rate is lower than peak connection and host IO throughput, in some cases by as much as 50% or lower, (ii) xdd request sizes that achieve peak throughput for host file IO do not necessarily lead to peak file transfer rates, and (iii) parallelism in host IO and TCP transport does not always improve the file transfer rates.

log-haul connections↗

DOE OSTI2019

Throughput Analytics of Data Transfer Infrastructures

To support increasingly distributed scientific and big-data applications, powerful data transfer infrastructures are being built with dedicated networks and software frameworks customized to distributed file systems and data transfer nodes. The data transfer performance of such infrastructures critically depends on the combined choices of file, disk, and host systems as well as network protocols and file transfer software, all of which may vary across sites. The randomness of throughput measurements makes it challenging to assess the impact of these choices on the performance of infrastructure or its parts. We propose regression-based throughput profiles by aggregating measurements from sites of the infrastructure, with RTT as the independent variable. The peak values and convex-concave shape of a profile together determine the overall throughput performance of memory and file transfers, and its variations show the performance differences among the sites. We then present projection and difference operators, and coefficients of throughput profiles to characterize the performance of infrastructure and its parts, including sites and file transfer tools. In particular, the utilization-concavity coefficient provides a value in the range [0, 1] that reflects overall transfer effectiveness. We present results of measurements collected using (i) testbed experiments over dedicated 0–366 ms 10 Gbps connections with combinations of TCP versions, file systems, host systems and transfer tools, and (ii) Globus GridFTP transfers over production infrastructure with varying site configurations.

Rao, Nageswara S.↗

DOE OSTI2020

Computational Methods to Accelerate Development of Corrosion Resistant Coatings for Industrial Gas Turbines

Oxidation resistant overlay coatings protect the underlying superalloy component in industrial gas turbines from oxidation attack. Rate of depletion of the Al-rich β-phase in the bond coat governs the lifetime of these coatings. The applicability of a computational method in accelerating the development of corrosion resistant coatings and significantly reducing the extensive experimental effort to predict coating lifetimes and microstructural changes in three-coated Ni-based superalloys for real operational durations (20–40 kh) was undertaken in the present study. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and electron microprobe analysis (EPMA) were employed to characterize MCrAlY-coated superalloy substrates (1483, 247 and X4) after exposure at 900 °C in air + 10% H 2 O for up to 20,000 h. The model predicted the longest coating lifetime for the coating on X4 substrate. Precipitation of γ' in the coatings was correctly predicted for all three coating systems. Additionally, the model was able to predict the formation of topologically close packed (TCP)-phases in the investigated coating systems.

Pillai, Rishi R.↗

DOE OSTI2018

Red and Yellow Luminescence of Eu{sup 3+}/Dy{sup 3+} Co-Doped Hydroxyapatite/β-Tricalcium Phosphate Single Phosphors Synthesized Using Coprecipitation Method

This paper reports the first attempt at the synthesis of single phosphors of europium (Eu{sup 3+}) and dysprosium (Dy{sup 3+}) co-doped hydroxyapatite (HA)/β-tricalcium phosphate (TCP) nanostructures providing strong red and yellow luminescence depending on annealing temperature and holding time. The morphology of the phosphors was observed to have a nanowire structure. The photoluminescence (PL) intensity of the phosphors increases with annealing temperature and time. The luminescent phosphors also showed the typical luminescence of Eu{sup 3+} centered at 610 nm and Dy{sup 3+} centered at 572 nm, which was more efficient for the annealed Eu{sup 3+}/Dy{sup 3+} co-doped HA/TCP phosphors than for as-synthesized ones. These results suggest that the Eu{sup 3+} and Dy{sup 3+} co-doped HA/TCP nanostructures can find potential application in plant cultivation as environment friendly phosphors.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

DOE OSTI2018

Creep Properties of Directionally Solidified Nb-Modified Ni-Base Superalloy, Mar-M247

The Ni-base superalloy Mar-M247 is widely used for elevated-temperature applications in both equiaxed and directionally solidified forms. The alloy contains about 3 wt.% Ta. Due to the cost and density of Ta, an atom-for-atom substitution of Nb for Ta was investigated. The creep properties in the temperature range of 750-950 °C and stresses ranging from 200 to 1000 MPa were determined. In general, the creep properties of the Nb-modified Mar-M247 material were very similar to those of Mar-M247 samples at 750 and 850 °C. However, the Mar-M247 samples exhibited superior creep properties at 950 °C. The lower creep properties of the Nb-modified Mar-M247 are likely due to the finer starting microstructure, more rapid coarsening rate of the γ′ and reduced γ′ strengthening effect (i.e., APB energy) of Nb, compared to Ta. No evidence of TCP phases was observed in either alloy.

36 MATERIALS SCIENCE↗

DOE OSTI2014

Combined Recipe for Clinical Target Volume and Planning Target Volume Margins

Purpose: To develop a combined recipe for clinical target volume (CTV) and planning target volume (PTV) margins. Methods and Materials: A widely accepted PTV margin recipe is M{sub geo} = aΣ{sub geo} + bσ{sub geo}, with Σ{sub geo} and σ{sub geo} standard deviations (SDs) representing systematic and random geometric uncertainties, respectively. On the basis of histopathology data of breast and lung tumors, we suggest describing the distribution of microscopic islets around the gross tumor volume (GTV) by a half-Gaussian with SD Σ{sub micro}, yielding as possible CTV margin recipe: M{sub micro} = ƒ(N{sub i}) × Σ{sub micro}, with N{sub i} the average number of microscopic islets per patient. To determine ƒ(N{sub i}), a computer model was developed that simulated radiation therapy of a spherical GTV with isotropic distribution of microscopic disease in a large group of virtual patients. The minimal margin that yielded D{sub min} <95% in maximally 10% of patients was calculated for various Σ{sub micro} and N{sub i}. Because Σ{sub micro} is independent of Σ{sub geo}, we propose they should be added quadratically, yielding for a combined GTV-to-PTV margin recipe: M{sub GTV-PTV} = √([aΣ{sub geo}]{sup 2} + [ƒ(N{sub i})Σ{sub micro}]{sup 2}) + bσ{sub geo}. This was validated by the computer model through numerous simultaneous simulations of microscopic and geometric uncertainties. Results: The margin factor ƒ(N{sub i}) in a relevant range of Σ{sub micro} and N{sub i} can be given by: ƒ(N{sub i}) = 1.4 + 0.8log(N{sub i}). Filling in the other factors found in our simulations (a = 2.1 and b = 0.8) yields for the combined recipe: M{sub GTV-PTV} = √((2.1Σ{sub geo}){sup 2} + ([1.4 + 0.8log(N{sub i})] × Σ{sub micro}){sup 2}) + 0.8σ{sub geo}. The average margin difference between the simultaneous simulations and the above recipe was 0.2 ± 0.8 mm (1 SD). Calculating M{sub geo} and M{sub micro} separately and adding them linearly overestimated PTVs by on average 5 mm. Margin recipes based on tumor control probability (TCP) instead of D{sub min} criteria yielded similar results. Conclusions: A general recipe for GTV-to-PTV margins is proposed, which shows that CTV and PTV margins should be added in quadrature instead of linearly.