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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Oscillatory instability development in extraction system of a negative ion source

Conditions of oscillatory instability development in the extraction system of a negative hydrogen ion source based on a volume-produced plasma are studied. Such an ion source is characterized by the presence of the parent gas in the extraction system due to the leakage from the gas-discharge chamber. The secondary electrons in the area of the ion-optical system become the reason of oscillation appearance and possible beam current modulation. Analytically the range of the stable beam propagation is found. The instability increment is shown to be rather small. Maximum increment of the oscillations corresponds to the beam velocity equal to the thermal velocity of plasma electrons. The group velocity of the oscillations is close to the beam velocity so the oscillations are convective. Simulation of the low energy beam propagation is performed in COMSOL Multiphysics, the beam current modulation being observed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

Monitoring of Photovoltaic (PV) Performance and Degradation: Integrated Renewable Energy Systems (IRES) - PV Monitoring Task

The Integrated Renewable Energy System (IRES) testbed demonstration at the Pacific Northwest National Laboratory (PNNL) Sequim campus includes development of a suite of capabilities for tracking the performance of photovoltaic (PV) renewable energy components located on a floating platform (floating PV) and on a shoreline building rooftop. The marine environment represents potentially harsh and corrosive conditions for PV modules. Compared to terrestrial PV, potential concerns for offshore PV arising from high humidity and occasional contact with saltwater, marine wildlife, and aquaculture. These environmental factors can reduce electricity generation efficiency and increase the risk of electrical faults, polymer insulation or jacketing degradation and hydrolysis of the PV cell encapsulant materials. Offshore PV modules may also be exposed to lower temperatures and buoyant and vibrating motions with a floating platform. It is not clear how the long-term performance of floating PV will be affected by these factors. To understand expected energy generation through solar cells on a floating platform, monitoring of the performance of PV modules in the marine environment is needed. This report outlines a plan for long-term testing of IRES PV components utilizing resources of the PNNL Material Aging and Detection (MAaD) Science team and the Marine and Coastal Research Laboratory (MCRL). Equipment applicable for onsite testing and real-time monitoring of the PV performance associated with environmental conditions including temperature, solar irradiance, shading and soiling is included. In case of performance loss, equipment for fault detection, failure analysis, material testing, and further troubleshooting are also available. Through establishment of this capabilities, the enabling IRES project sets the stage for future research to advance off-shore and near-shore energy options for businesses and communities.

14 SOLAR ENERGY↗
DOE OSTI2023

Synthesis of 2H/ fcc -Heterophase AuCu Nanostructures for Highly Efficient Electrochemical CO 2 Reduction at Industrial Current Densities

Structural engineering of nanomaterials offers a promising way for developing high-performance catalysts toward catalysis. However, the delicate modulation of thermodynamically unfavorable nanostructures with unconventional phases still remains a challenge. Here, in this study, the synthesis of hierarchical AuCu nanostructures is reported with hexagonal close-packed (2H-type)/face-centered cubic (fcc) heterophase, high-index facets, planar defects (e.g., stacking faults, twin boundaries, and grain boundaries), and tunable Cu content. The obtained 2H/fcc Au 99 Cu 1 hierarchical nanosheets exhibit excellent performance for the electrocatalytic CO 2 reduction to produce CO, outperforming the 2H/fcc Au 91 Cu 9 and fcc Au 99 Cu 1 . The experimental results, especially those obtained by in-situ differential electrochemical mass spectroscopy and attenuated total reflection Fourier-transform infrared spectroscopy, suggest that the enhanced catalytic performance of 2H/fcc Au 99 Cu 1 arises from the unconventional 2H/fcc heterophase, high-index facets, planar defects, and appropriate alloying of Cu. Impressively, the 2H/fcc Au 99 Cu 1 shows CO Faradaic efficiencies of 96.6% and 92.6% at industrial current densities of 300 and 500 mA cm -2 , respectively, as well as good durability, placing it among the best CO 2 reduction electrocatalysts for CO production. The atomically structural regulation based on phase engineering of nanomaterials (PEN) provides an avenue for the rational design and preparation of high-performance electrocatalysts for various catalytic applications.

36 MATERIALS SCIENCE↗
DOE OSTI2021

3-D Prismatic Packaging Methodologies for Wide Band Gap Power Electronics Modules

In a power module the parasitic inductance limits the dynamic high-frequency performance, and the area of the cooling surfaces limits the power capability. This paper presents a new 3D power electronic design methodology based on the concept of mutual inductance cancellation and multi-sided heat transfer. New 3D prismatic packaging concepts are proposed for Wide Band Gap (WBG) power devices, where the devices can be mounted at acute angles to adjacent interconnects or other devices. Discussion is given on electrical and thermal path optimization in a 3D space. To validate the 3D prismatic packaging methodology, a 1200V/50A SiC half-bridge power module is fabricated and tested for electrical and thermal performance and results are compared with simulations. The power density calculated for the module is 12 kW/in3 (including heatsink) and shows a 31.3% inductance reduction compared to a 2D planar module. Finally, design guidance suggested for utilizing prismatic structures is provided, together with suggested future work in the area. This paper presents the first reported true 3D power module.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2023

SFRC Measurement Control Summary - FY23 Q3/Q4

Measurements with the Spent Fuel Rod Counter (SFRC) to be performed bi annually include 3 He detector efficiency checks (in both modules) and ion chamber channel tests with a pocket pulser. These measurements will all be performed at TA-35, building 27 where the SFRC is stored. Refer to LA-UR-22-31737 and LA-CP-22-20079 SFRC measurement control documents for a description of additional tests. Note that during this measurement period, counts could not be confirmed for the Si detectors, as an analog pulse to TTL box necessary for the DAQs to communicate with the detectors was still under construction. For this reason, typical measurements at the Calibrated Dose Facility were not performed for the second half of FY23. When these components are finished by the NEN electrical shop, the Si detectors will be implemented into these measurement control checks.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2023

Carbonic anhydrase textile structured packing for efficient CO 2 absorption in methyldiethanolamine solvent

Carbonic anhydrase (CA) is an attractive biodegradable catalyst for CO 2 absorption in solvent–based CO 2 capture. However, maintaining the stability of CA as a homogeneous component of the solvents is a challenge. Solvent regeneration temperature typically exceeds the enzyme thermal tolerance, which leads to CA deactivation. To reduce the need for frequent CA replenishment and to avoid inactive CA accumulation in the solvent, this work shows the benefits of an immobilization strategy where CA is fixed in a second–generation design of textile structured packing (CATSP–2) modules. The enzyme–immobilized packing showed 1.5 times better performance in CO 2 separation compared with traditional structured packing with a corresponding increased CO 2 loading in the rich solvent. The modules exhibited good CA activity retention of ~80% during the tests without any CA replenishment. As a result, applying CATSP–2 could potentially decrease the packing height and absorber column size for a lower cost per amount of CO 2 captured.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Direction Modulated Brachytherapy for Treatment of Cervical Cancer. II: Comparative Planning Study With Intracavitary and Intracavitary–Interstitial Techniques

Purpose: To perform a comprehensive comparative planning study evaluating the utility of the proposed direction modulated brachytherapy (DMBT) tandem applicator against standard applicators, in the setting of image guided adaptive brachytherapy of cervical cancer. Methods and Materials: A detailed conceptual article was published in 2014. The proposed DMBT tandem applicator has 6 peripheral grooves of 1.3-mm width, along a 5.4-mm-thick nonmagnetic tungsten alloy rod of density 18.0 g/cm{sup 3}, capable of generating directional dose profiles. We performed a comparative planning study with 45 cervical cancer patients enrolled consecutively in the prospective observational EMBRACE study. In all patients, MRI-based planning was performed while utilizing various tandem-ring (27 patients) and tandem-ring-needles (18 patients) applicators, in accordance with the Groupe Européen de Curiethérapie–European Society for Radiotherapy and Oncology recommendations. For unbiased comparisons, all cases were replanned with an in-house–developed inverse optimization code while enforcing a uniform set of constraints that are reflective of the clinical practice. All plans were normalized to the same high-risk clinical target volume D90 values achieved in the original clinical plans. Results: In general, if the standard tandem was replaced with the DMBT tandem while maintaining all other planning conditions the same, there was consistent improvement in the plan quality. For example, among the 18 tandem-ring-needles cases, the average D2cm{sup 3} reductions achieved were −2.48% ± 11.03%, −4.45% ± 5.24%, and −5.66% ± 6.43% for the bladder, rectum, and sigmoid, respectively. An opportunity may also exist in avoiding use of needles altogether for when the total number of needles required is small (approximately 2 to 3 needles or less), if DMBT tandem is used. Conclusions: Integrating the novel DMBT tandem onto both intracavitary and intracavitary–interstitial applicator assembly enabled consistent improvement in the sparing of the OARs, over a standard “single-channel” tandem, though individual variations in benefit were considerable. Although at an early stage of development, the DMBT concept design is demonstrated to be useful and pragmatic for potential clinical translation.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

Effect of packaging and cooling plates on mechanical response and failure characteristics of automotive Li-ion battery modules

When a battery pack is subjected to external mechanical load, i.e. as in the case of crash, the individual cells experience significant deformations leading to the internal short circuit and possibly fire. The current investigation looks into effects of the inactive components (i.e. cooling plates and module protective enclosure) on deformation and failure of individual pouch cells. Experiments on large spherical indentation of electric vehicle battery module with and without such components have been performed. The results show that the presence of cooling plates overall reduces the force under out-of-plane indentation by approximately a factor of 1.5. It was established however that the failure in cells occurs at the same displacement of the indenter, regardless of the presence of the inactive elements in battery module structure. This underlines the necessity for formulation of the failure criterion based on critical strain, rather than critical stress measure. The findings suggest possibility of utilizing such battery modules in impact energy absorption scenarios, due to reduction in force by the cooling components. X-Ray computed tomography (XCT) has been performed on the cells as a non-destructive analysis of internal failure and the differences of failure mode induced by introduction of structural components are discussed.

25 ENERGY STORAGE↗
DOE OSTI2020

Parametric study of optical transmission through plasmonic hole arrays modulated by the phase transition of vanadium dioxide

We have performed comprehensive electromagnetic simulations and preliminary experiments to explore the effects of geometrical and material parameters on the extraordinary optical transmission (EOT) through periodic arrays of subwavelength holes in a bilayer stack consisting of a gold or silver film atop a vanadium dioxide film (Au/Ag + VO 2 ), where the latter undergoes a semiconductor-to-metal phase transition. Using the finite-difference time-domain (FDTD) and finite-element methods (FEM), we vary iteratively the array periodicity, VO 2 film thickness and hole diameters, as well as the refractive index inside the VO 2 -layer holes and the VO 2 optical constants. For each variation, we compare the metallic-to-semiconducting ratios of the zero-order transmission ( T 00 ) peaks and find sharp maxima in these ratios within narrow parameter ranges. The maxima arise from Fabry-Perot and Fano-type resonances that minimize T 00 in the semiconducting phase of the perforated bilayers. At a fixed array period, the primary factors controlling the VO 2 -enabled EOT modulation are the VO 2 thickness, diameter of the VO 2 -layer holes, and absorption in the two VO 2 phases. Besides uncovering the origins of the higher metallic-phase T 00 , this study provides a protocol for optimizing the performance of the bilayer hole arrays for potential uses as dynamically tunable nano-optical devices.

Donev, Eugenii U. (ORCID:000000030555219X)↗
DOE OSTI2017

Characterizing Density and Complexity of Imported Cargos

X-ray inspection systems are used to detect radiological and nuclear threats in imported cargo. In order to better understand performance of these systems, system imaging capabilities and the characteristics of imported cargo need to be determined. This project involved calculation of the modulation transfer function as a metric of system imaging performance and a study of the density and inhomogeneity of imported cargos, which have been shown to correlate with human analysts, threat detection performance.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2015

Characterization of 750 Large Area Photomultipliers for the KM3NeT-Italia towers

The KM3NeT European experiment aims to construct a large volume underwater neutrino telescope, in the depths of the Mediterranean Sea. Thanks to a dedicated funding by the Italian Ministry of Education, University and Research, in its first phase named KM3NeT-Italia, an 8-towers detector is under construction, equipped with 672 optical sensors. The detection element of the telescope, the 'optical module', is composed by a 13-inch high-pressure glass-vessel that contains a single 10-inch photomultiplier. As the key sensor, all the characteristics of the photomultiplier have a severe impact on the performance of the whole detector. The selected photomultiplier was the 10-inch R7081 PMT produced by Hamamatsu. In the frame of the optical modules mass production, performed in the INFN-LNS site of Catania, 750 photomultipliers have been tested by means of a dedicated test bench. The paper deals with the main results obtained from the massive photomultipliers measurements, which exhibited that such kind of devices comply with the general requirements imposed by the project. (authors)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

A method for evaluating image quality of monochrome and color displays based on luminance by use of a commercially available color digital camera

Purpose: The aim of this study is to propose a method for the quantitative evaluation of image quality of both monochrome and color liquid-crystal displays (LCDs) using a commercially available color digital camera. Methods: The intensities of the unprocessed red (R), green (G), and blue (B) signals of a camera vary depending on the spectral sensitivity of the image sensor used in the camera. For consistent evaluation of image quality for both monochrome and color LCDs, the unprocessed RGB signals of the camera were converted into gray scale signals that corresponded to the luminance of the LCD. Gray scale signals for the monochrome LCD were evaluated by using only the green channel signals of the camera. For the color LCD, the RGB signals of the camera were converted into gray scale signals by employing weighting factors (WFs) for each RGB channel. A line image displayed on the color LCD was simulated on the monochrome LCD by using a software application for subpixel driving in order to verify the WF-based conversion method. Furthermore, the results obtained by different types of commercially available color cameras and a photometric camera were compared to examine the consistency of the authors’ method. Finally, image quality for both the monochrome and color LCDs was assessed by measuring modulation transfer functions (MTFs) and Wiener spectra (WS). Results: The authors’ results demonstrated that the proposed method for calibrating the spectral sensitivity of the camera resulted in a consistent and reliable evaluation of the luminance of monochrome and color LCDs. The MTFs and WS showed different characteristics for the two LCD types owing to difference in the subpixel structure. The MTF in the vertical direction of the color LCD was superior to that of the monochrome LCD, although the WS in the vertical direction of the color LCD was inferior to that of the monochrome LCD as a result of luminance fluctuations in RGB subpixels. Conclusions: The authors’ method based on the use of a commercially available color camera is useful to evaluate and understand the display performances of both monochrome and color LCDs in radiology departments.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Coupling the System Analysis Module with SAS4A/SASSYS-1

SAS4A/SASSYS-1 is a simulation tool used to perform deterministic analysis of anticipated events as well as design basis and beyond design basis accidents for advanced reactors, with an emphasis on sodium fast reactors. SAS4A/SASSYS-1 has been under development and in active use for nearly forty-five years, and is currently maintained by the U.S. Department of Energy under the Office of Advanced Reactor Technology. Although SAS4A/SASSYS-1 contains a very capable primary and intermediate system modeling component, PRIMAR-4, it also has some shortcomings: outdated data management and code structure makes extension of the PRIMAR-4 module somewhat difficult. The user input format for PRIMAR-4 also limits the number of volumes and segments that can be used to describe a given system. The System Analysis Module (SAM) is a fairly new code development effort being carried out under the U.S. DOE Nuclear Energy Advanced Modeling and Simulation (NEAMS) program. SAM is being developed with advanced physical models, numerical methods, and software engineering practices; however, it is currently somewhat limited in the system components and phenomena that can be represented. For example, component models for electromagnetic pumps and multi-layer stratified volumes have not yet been developed. Nor is there support for a balance of plant model. Similarly, system-level phenomena such as control-rod driveline expansion and vessel elongation are not represented. This report documents fiscal year 2016 work that was carried out to couple the transient safety analysis capabilities of SAS4A/SASSYS-1 with the system modeling capabilities of SAM under the joint support of the ART and NEAMS programs. The coupling effort was successful and is demonstrated by evaluating an unprotected loss of flow transient for the Advanced Burner Test Reactor (ABTR) design. There are differences between the stand-alone SAS4A/SASSYS-1 simulations and the coupled SAS/SAM simulations, but these are mainly attributed to the limited maturity of the SAM development effort. The severe accident modeling capabilities in SAS4A/SASSYS-1 (sodium boiling, fuel melting and relocation) will continue to play a vital role for a long time. Therefore, the SAS4A/SASSYS-1 modernization effort should remain a high priority task under the ART program to ensure continued participation in domestic and international SFR safety collaborations and design optimizations. On the other hand, SAM provides an advanced system analysis tool, with improved numerical solution schemes, data management, code flexibility, and accuracy. SAM is still in early stages of development and will require continued support from NEAMS to fulfill its potential and to mature into a production tool for advanced reactor safety analysis. The effort to couple SAS4A/SASSYS-1 and SAM is the first step on the integration of these modeling capabilities.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2016

GFDM performance in terms of BER, PAPR and OOB and comparison to OFDM system

Generalized frequency division multiplexing is a multicarrier modulation technique which can be foreseen as a potential alternative for upcoming wireless networks. GFDM attractive features include reduced out-of-band radiation(OOB) and low peak-to-average ratio(PAPR), which are the crucial shortcomings of OFDM used in present day wireless communication networks. This paper gives detailed description of GFDM system model and further studies and validates through simulations, the performance of GFDM in terms of OOB, PAPR and Bit Error Rate (BER) and compares the results obtained with OFDM system.

42 ENGINEERING↗
DOE OSTI2023

Luminescence and Thermal Imaging Applied to Half-Cut-Cell and Emitter-Wrap-Through-Cell Modules

Imaging techniques provide spatial details and visualization of module defects and degradation mechanisms that affect energy conversion efficiency and performance. We apply photoluminescence, electroluminescence, and dark lock-in thermography imaging techniques to evaluate new modules in their initial state and after applying stresses of damp heat, light-induced-degradation regeneration parameters, thermal cycling, and humidity-freeze cycles. One module uses emitter-wrap-through cells with back contacts connected to a metal-foil backplane, and the other is composed of half-cut cells. Imaging shows examples on non-uniform degradation and damage such as cells that degrade and recover under the applied conditions, cells with cracks and handling damage, and cells with increasing series resistance.

degradation↗
DOE OSTI2021

Techno-economic Analysis of Novel PV Plant Designs for Extreme Cost Reductions

A techno-economic analysis is underway examining the cost and performance of future large-scale photovoltaic (PV) plant components, including bifacial modules, tandem modules, increased plant voltage architectures, and module-level power electronics. Integration of these components into PV plant designs is compared with current PV technologies based on levelized cost of electricity (LCOE). Baseline models are developed and validated against recorded PV plant performance data. Expected cost and performance data of future PV technologies are incorporated into the baseline models. An evolutionary algorithm is utilized to optimize PV plant configuration, technology combination, and LCOE. Furthermore, this paper focuses on the bifacial module analysis.

14 SOLAR ENERGY↗
DOE OSTI2016

Comparison of Hybrid K-Edge Densitometer (HKED) Performance Operating with the Canberra Lynx MCA and the Canberra ICB-NIM Electronics

From the 1991 until 2008 the Canberra Hybrid K-Edge Densitometer systems were provided with ICB-NIM (Integrated Control Bus – Nuclear Instrument Module) acquisition electronics. Newer electronics modules, such as the Lynx, were not supported under the VMS based operating system. The LYNX module was provided as the standard acquisition electronics following the release of the Windows based CHKED software. This report compares the electronics dead-time, gain shifts, detector resolution and measurement performance of the HKED system operated with the two types of acquisition modules. The comparison was performed using measurements obtained with the ORNL HKED system. The original intent of this study was to take advantage of both the timing and energy outputs from the HPGE detector to acquire data with both sets of electronics in parallel. Although this approach has been applied successfully with other systems, in this case we found the timing output produced a significant amount of noise such that a comparison between the electronics would be invalid. So the comparative measurements were performed sequentially. The ICB-NIM data was acquired over the course of 12 months with 255 measurements while the LYNX data was acquired over a period of 10 months with 75 measurements. To simplify the comparison, all data used in this study was acquired using the Canberra CHKED (V1.0) software package. The performance analysis was based primarily on the peak locations, peak widths and concentration values reported by the CHKED software. The raw spectra from the XRF measurements were also examined to extract additional 109Cd peak location and width data for the hybrid measurements (the standard hybrid report template does not report these values).

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2020

Learning from existing photovoltaic technologies to identify alternative perovskite module designs

Perovskite solar cells have now become the most efficient of all multicrystalline thin film photovoltaic technologies, reaching 25.2% in 2019. This outstanding figure of merit has only been achieved on small lab-scale devices, with significantly lower performance when processed on larger more industrially relevant substrate sizes. Perovskite modules, connecting several smaller area cells together, are commonly demonstrated with a superstrate monolithic interconnection method. However, several other module designs exist and remain largely unexplored by the perovskite community. In this work, we review and highlight those alternatives and discuss their advantages and limitations. We propose that a singulated substrate-oriented module design, using metallic substrates, could provide a quicker path to seeing highly efficient, lightweight, and flexible perovskite modules on the market, while mitigating near-term technical risks. Finally, as an experimental starting-point towards this design, we demonstrate a substrate-oriented all-perovskite 2-terminal tandem with 18% efficiency.

14 SOLAR ENERGY↗