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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 649 records · Page 36

Wear and Why? How Ash Elements Can Help Define Wear Profiles of Biomass Feedstocks

Biomass feedstocks have been shown to cause high wear rates on biomass processing equipment, including grinders, pneumatic conveyance systems, and screw feeders. Previously, wear rates were positively correlated with ash concentrations. Physical and chemical properties, including ash content, vary across the anatomy of plants in biomass feedstocks. To better understand biomass tissues that cause the most wear, anatomical fractions of pine forest residues were tested for wear properties. Fractions were tested in the Accelerated Wear Testing Apparatus using steel coupon mass loss to evaluate wear rates. Extrinsic ash was extracted and characterized. Total ash content of the forest residue was 0.80wt%. Anatomical fractions showed varied amounts of ash with highest concentrations in bark and needles (2.33wt%, 3.52wt%, respectively). The wear rate of the forest residue was 2.36mg loss per kg biomass. Low ash fractions, including whitewood and cambium, caused little wear. Bark had lower ash than the needles but resulted in more wear (8.63 vs 5.57mg loss per kg biomass). Bark contained the most extrinsic ash and largest ash particle size, while needles contained the least extrinsic ash and smallest ash particle size. These findings indicate that total ash content (intrinsic plus extrinsic), soil contamination, and elemental analysis can provide information related to wear properties of biomass materials; however, these analyses do not fully explain the differences observed in the wear rates of bark and needles. Additional testing is to determine other parameters of importance.

Lacey, Jeffrey A.↗

SLAC National Accelerator Laboratory FACET & TEST BEAM FACILITIES PROPOSAL: Development of Electron Radiography for Material Science

The material science community is presently limited by diagnostics in both the fabrication of materials and measuring the resulting materials characteristics of these new fabrication techniques. Because of this limitation the community is forced into an empirical mode of material fabrication, where expert judgment is used to guide manufacturing processes and the resulting materials are inspected and tested for the desired characteristics. This development approach can be time consuming and costly. The solution to this problem is to improve our fundamental understanding of materials, which requires the development of new diagnostics capable of measurement at the micron length scale, during both processing and during testing. These new measurements will enable a fundamental understanding of material characteristics allowing the development of predictive models, which will in turn enable material engineering by design rather than today’s empirical approach. Solving this problem has become a grand challenge for the materials science community. Los Alamos plans to address this challenge through the development of new diagnostics capable of measurements at the smallest length scales through the Multi-Probe Diagnostic Hall (MPDH) at the planned MaRIE (Material and Radiation In Extremes) Facility. One of the probes will be a coherent photon beam generated by an FEL driven by a multi-GeV electron beam. The photons will be used for diffraction measurements as well as radiography of relatively thin samples (nearly single grains). The same multi-GeV electron beam can be used to directly radiograph thicker systems (many grains or “bulk” material), providing high resolution measurements of the density distribution of materials during both fabrication and dynamic testing. This technique, electron radiography or eRad, that has been identified by LANL as one of the probes required to meet this grand challenge has never been demonstrated with high energy electrons. We propose to begin development of this technique with the electron beam available at FACET.

47 OTHER INSTRUMENTATION↗

Implementation of a Biaxial Resonant Fatigue Test Method on a Large Wind Turbine Blade

A biaxial resonant test method was utilized to simultaneously fatigue test a wind turbine blade in the flap and edge (lead-lag) direction. Biaxial resonant blade fatigue testing is an accelerated life test method utilizing oscillating masses on the blade; each mass is independently oscillated at the respective flap and edge blade resonant frequency. The flap and edge resonant frequency were not controlled, nor were they constant for this demonstrated test method. This biaxial resonant test method presented surmountable challenges in test setup simulation, control and data processing. Biaxial resonant testing has the potential to complete test projects faster than single-axis testing. The load modulation during a biaxial resonant test may necessitate periodic load application above targets or higher applied test cycles.

17 WIND ENERGY↗

Theoretical and Computational Studies of Rare Earth Substitutes: A Test-bed for Accelerated Materials Development

Hard permanent magnets in wide use typically involve expensive Rare Earth elements. In this effort, we investigated candidate permanent magnet materials which contain no Rare Earths, while simultaneously exploring improvements in theoretical methodology which enable the better prediction of magnetic properties relevant for the future design and optimization of permanent magnets. This included a detailed study of magnetocrystalline anisotropy energies, and the use of advanced simulation tools to better describe magnetic properties at elevated temperatures.

36 MATERIALS SCIENCE↗

The Geothermal Entrepreneurship Organization (GEO) Accelerating Technology Transfer, Testing and Adoption of Cutting-edge Extreme Environment Drilling

The Geothermal Entrepreneurship Organization launched in 2019 with the goal of building a geothermal innovation ecosystem at the University of Texas at Austin (UT Austin), and in the State of Texas at large. The theses underlying the work of GEO were 1) that with targeted advocacy, recruitment, organization, and coalition building, research institutions with legacy excellence in petroleum and geosystems engineering could become engines of geothermal innovation, research and development; 2) that startups were the appropriate vehicle to speed these innovations from the lab into the field, and building a geothermal startup ecosystem in Texas would not only advance next generation geothermal concepts into the field, but also help spur oil and gas engagement in the space, and 3) that with targeted engagement, education, and recruitment across stakeholders in the oil and gas industry and the State of Texas generally, the oil and gas industry, and other legacy oil and gas entities in the State could become sources of large scale deployment of geothermal energy. The overall goal was to create a ‘snowball’ effect, where targeted impactful actions would catalyze self-sustaining, organic growth of a new geothermal ecosystem in the State of Texas. That goal was achieved through GEO’s work. To test its theses, GEO began work by interviewing and recruiting UT Austin faculty and alumni into geothermal. At the beginning of the GEO project, there was no geothermal activity ongoing within the UT Austin Petroleum and Geosystems Engineering Department, the Bureau of Economic Geology, or the Jackson School of Geoscience, and many faculty approached had not before considered how their skillsets might apply in the space. By the end of the project period, three major research consortia focused on geothermal were launched as a result of GEO’s work, one at the Bureau of Economic Geology, one within the Petroleum and Geosystems Engineering Department, and another organized by GEO across six research institutions across the State of Texas, called the Texas Geothermal Institute. Geothermal curricula was launched at UT Austin, and UT Austin began attracting new geothermal enthusiasts into its faculty, including Dr. Silviu Livescu, former Chief Scientist of Baker Hughes. Startups recruited and mentored by GEO launched, raised funding, and deployed (or are currently deploying) their concepts in the field. By the end of the project period, the GEO concept expanded to faculty beyond UT Austin to other institutions, like Texas A&M, the University of Houston, and Rice University, and geothermal engagement began at those institutions as well. Multiple faculty members and alumni across these institutions launched geothermal startup companies, launched geothermal research consortia, and/or began teaching geothermal courses. In 2020, GEO launched what was to become the largest geothermal conference in the world by its second year, ‘PIVOT – From Hydrocarbons to Heat’, and the resulting momentum catalyzed the Society of Petroleum Engineers to launch a geothermal technical section, drove more startups to launch out of the ecosystem, and drove actors in the State of Texas, NGOs, and stakeholders globally to become engaged. Riding this momentum, the Texas Geothermal Energy Alliance was launched, the first ever industry association dedicated to advancing geothermal energy in the State of Texas. The Texas geothermal ecosystem after only two years of building and support is now robust, quickly growing, and self-sustaining. By 2021, the Texas geothermal ecosystem had attracted the attention of philanthropists, funding entities, media, and influencers outside of Texas, and GEO’s executive director was invited to give a TED talk about oil and gas engagement in building the future of geothermal energy, which elevated the success of the ecosystem to a global audience.

15 GEOTHERMAL ENERGY↗

Laboratory Accelerated Cyclic Corrosion Testing and On-Road Corrosion Testing of AA6××× Coupled to Carbon Fiber-Reinforced Plastics

Structures made from a combination of aluminum alloy (AA) and carbon fiber-reinforced plastic (CFRP) are susceptible to galvanic corrosion of the AA in harsh atmospheric conditions, such as might exist for closure panels in automotive applications. It is important to understand the galvanic corrosion behavior of these materials under laboratory conditions as that might allow prediction of performance in real environments. This work tested specially designed AA6×××-CFRP coupons, including AA6111 and AA6022, connected to CFRP made from two different carbon fiber fabrics (twill and random) with the aim of understanding the corrosion behaviors in a laboratory cyclic exposure chamber and during on-road exposure. The extent of corrosion was assessed by galvanic current measurements, optical profilometry, cross-sectional area analysis, and microscopic analysis. Based on the results, it was determined that the corrosion susceptibilities and morphologies observed in CFRP/AA couples tested in an environmental chamber for 12 weeks were in correspondence with those of the coupons subjected to on-road testing for 1 y in Columbus, OH.

Materials Science↗

Mesoscale Modeling of the Effects of Accelerated Burnup on UO2 Microstructural Evolution

Accelerating the nuclear fuel qualification process will rely on some combination of advanced modeling and simulation techniques with accelerated irradiation testing and separate effects experiments to enable the development of new fuel concepts in a shorter time frame. One of the key challenges to successfully leveraging accelerated irradiation tests will be understanding the artifacts that may be introduced with accelerated accumulation of dose and/or burnup. This work presents phase field (MARMOT) simulations of the evolution of representative 2D UO2 microstructures up to 40 MWd/kgU. Simulations were performed under both commercial light water reactor fuel conditions as well as those that would be expected for highly accelerated (~10x) burnup conditions similar to those used in the MiniFuel irradiations in Oak Ridge National Laboratory’s High Flux Isotope Reactor. The phase field model was coupled with a discrete nucleation algorithm to model re- structuring at high burnup. The effect of the different fission rates in both microstructures was investigated at two temperatures: 650?C and 800?C. The lower temperature simulations both showed an onset of restructuring at nearly 60 MWd/kgU. More extensive restructuring was obtained in the MiniFuel microstructure compared with that of the PWR fuel. At 800?C, no restructuring was obtained as a result of the thermally activated diffusion of Xe atoms and U vacancies to fission gas bubbles, which reduces the nucleation driving force. These results highlight the importance of using modeling and simulation tools to inform the environmental conditions during targeted accelerated irradiation tests to extract the most useful fuel performance data.

accelerated fuel qualification, Phase Field, Restr↗

Performance and durability of electrically conductive tape for shingled Si heterojunction technology cells

We report electrically conductive tape (ECT) was characterized and used to assemble shingled cell strings at low temperature to achieve high reliability Pb- and Ag-free interconnections. The volume resistivity for two considered ECTs are 0.13 ± 0.06 mΩ·cm and 0.47 ± 0.20 mΩ·cm and specific contact resistances, 6.85± 2.00 mΩ·cm 2 and 6.30 ± 0.37 mΩ·cm 2 using the emerging IEC 62788-8-1 Technical Specification for assessment of electrically conductive adhesives (ECA). Durability and performance of the technology in glass–glass mini modules were evaluated with temperature cycling, damp heat testing, and combined-accelerated stress testing (CAST). Through temperature cycling (-40°C to 85°C) applying five times the mini module short-circuit current in forward bias and in the multi climate CAST protocol, there was negligible degradation of fill factor after replacing connectors at the modules' cable leads; however, CAST resulted in short circuit current loss attributed to degradation in light collection by the cells, not the ECT. The IEC 61215-2 85°C, 85% relative humidity damp heat testing showed susceptibility of the HJT cells to effects of humidity in the electroluminescence intensity around the module perimeter that degraded power performance by 4% (relative). Contrasting the IEC 61215-2 qualification testing-based damp heat testing with CAST, factors such as the optical stress of CAST may precipitate the degradation of the modules whereas the humidity levels and duration of IEC 61215-2 damp heat testing may lead to excessive levels of humidity diffused into the modules, potentially resulting in degradation that is unrepresentative of the field.

14 SOLAR ENERGY↗

Beam Diagnostic Challenges for FACET-II

FACET-II, the Facility for Advanced Accelerator Experimental Tests II, is a new accelerator R&D test facility to be constructed at SLAC. It will provide high-energy, high-density electron and positron beams to advance the development of beam driven plasma wakefield acceleration and support a broad range of experiments. The FACET-II beams are expected to have 10 GeV energy, contain 2 nC of charge, have a transverse normalized emittance of 7 microns, be compressed to about 1 micron long and focused to about 6 micron wide at the interaction point. Additionally, the nominal peak current is 20 kA and is expected to fluctuate up to 200 kA. Most experiments desire complete knowledge of the incoming beam parameters on a pulse-to-pulse basis. However, the extreme beam densities and strong fields of the beam current will destroy any diagnostics intercepting the beam in a single shot and impose unique challenges for beam diagnostics. Moreover, non-intercepting diagnostics are desirable to provide feedback for machine setup and characterization. Finally, we need to look beyond conventional diagnostics to seek new solutions for measurements of the high charge, small beam size, short bunch length, and low emittance.

43 PARTICLE ACCELERATORS↗

Chapter 9: Reliability

This chapter describes the accumulated knowledge on CPV reliability with its fundamentals and qualification. It explains the reliability of solar cells, modules (including optics) and plants. The chapter discusses the statistical distributions, namely exponential, normal and Weibull. The reliability of solar cells includes: namely the issues in accelerated aging tests in CPV solar cells, types of failure and failures in real time operation. The chapter explores the accelerated life tests, namely qualitative life tests (mainly HALT) and quantitative accelerated life tests (QALT). It examines other well proven and experienced PV cells and/or semiconductor devices, which share similar semiconductor materials, manufacturing techniques or operating conditions, namely, III-V space solar cells and light emitting diodes (LEDs). It addresses each of the identified reliability issues and presents the current state of the art knowledge for their testing and evaluation. Finally, the chapter summarizes the CPV qualification and reliability standards.

14 SOLAR ENERGY↗

Long term reliability study and life time model of quantum cascade lasers

Here, we present results of quantum cascade laser lifetime tests under various aging conditions including an accelerated life test. The total accumulated life time exceeds 1.5 × 106 device hours. The longest single device aging time was 46 500 hours without failure in the room temperature aging test. Four failures were found in a group of 19 devices subjected to the accelerated life test with a heat-sink temperature of 60 °C and a continuous-wave current of 1 A. Failure mode analyses revealed that thermally induced oxidation of InP in the semi-insulating layer is the cause of failure. An activation energy of 1.2 eV is derived from the dependence of the failure rate on laser core temperature. The mean time to failure of the quantum cascade lasers operating at a typical condition with the current density of 5 kA/cm2 and heat-sink temperature of 25 °C is expected to be 809 000 hours.

Xie, Feng↗

Use of indentation to study the degradation of photovoltaic backsheets

The ability of electrical insulating materials within a module to act as insulators is a key safety requirement for photovoltaic (PV) technology. Presently, however, the durability of backsheets may not be readily assessed. For example, the mechanical tensile test continues to be developed, and its use has not been validated such that a technically based pass/fail criteria may be established. This study examines the use of simple indentation methods, including durometer hardness and instrumented indentation, as a means to quantitively assess the degradation of PV backsheets. Characteristics including: hardness, modulus, load/displacement profile, creep hold response, and residual impression are explored in an empirical study. Glass/encapsulant/backsheet mini-modules constructed using backsheets including: polyamide (PA), poly(ethylene terephthalate) (PET), polyvinyl fluoride (PVF) laminate ('TPE'), and polyvinylidene fluoride (PVDF) were examined. An M-type durometer as well as Berkovich and cube-corner tips were used in the indentation experiments. Additional characterizations were performed to interpret the indentation measurements including: surface roughness measurements using atomic force microscopy (AFM), a chemical integrity study using Fourier-transform infrared spectroscopy (FTIR), and phase-transition measurements using differential scanning calorimetry (DSC). The results are analyzed in the context of the combined accelerated stress test (C-AST) also explored in this study. Instrumented indentation (i.e., using a Berkovich tip) was able to distinguish between backsheets and quantify the effects of accelerated testing (including up to 60%, 25%, and 20% change in hardness, modulus, and creep displacement, respectively). The embrittlement of the backsheets was not readily assessable using cube-corner indentation. Cracking of the known-bad polyamide backsheet was observed from the C-AST, which was not observed to result from steady state UV weathering.

14 SOLAR ENERGY↗