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At least 433 records · Page 24

Capabilities of the Materials Contamination Team at Marshall Space Flight Center

The Materials Contamination Team at the Marshall Space Flight Center (MSFC) has been recognized for its contributions supporting the National Aeronautics and Space Administration (NASA) spacecraft development programs. These programs include the Reusable Solid Rocket Motor (RSRM), Chandra X-Ray Observatory, and the International Space Station (ISS). The Environmental Effects Group, with the Materials Contamination Team and the Space Environmental Effects Team has been an integral part of NASA's success by the testing, evaluation, and qualification of materials, hardware, and processes. This paper focuses on the capabilities of the Materials Contamination Team. The Materials Contamination Team's realm of responsibility includes establishing contamination control during all phases of hardware development, including design, manufacturing, assembly, test, transportation, launch site processing, on-orbit exposure, return, and refurbishment. The team continues its mission of reducing the risk of equipment failure due to molecular or particulate contamination. Contamination is a concern in the Space Shuttle with sensitive bond-lines and reactive fluid (liquid oxygen) compatibility as well as for spacecraft with sensitive optics, such as Hubble Space Telescope and Chandra X-ray Observatory. The Materials Contamination Team has a variety of facilities and instrumentation capable of contaminant detection, identification, and monitoring. The team addresses material applications dealing with environments, including production facilities, clean rooms, and on-orbit exposure. The optically stimulated electron emission (OSEE) system, the Ultraviolet (UV) fluorescence (UVF) surface contamination detection, and the Surface Optics Corporation 400 (SOC 400) portable hand-held Fourier Transform Infrared (FTIR) spectrometer are state-of-the-art tools for in-process molecular contamination detection. The team of engineers and technicians also develop contamination calibration standards and evaluate new surface cleanliness inspection technologies. The team utilizes facilities for on-orbit simulation testing of materials for outgassing and molecular film deposition characteristics in the presence of space environmental effects, such as Atomic Oxygen (AO) and UV radiation exposure. The Materials Contamination Team maintains databases for process materials as well as outgassing and optical compatibility test results for specific environments.

Burns, Howard↗

Solid Freeform Fabrication of Composite-Material Objects

Composite solid freeform fabrication (C-SFF) or composite layer manufacturing (CLM) is an automated process in which an advanced composite material (a matrix reinforced with continuous fibers) is formed into a freestanding, possibly complex, three-dimensional object. In CLM, there is no need for molds, dies, or other expensive tooling, and there is usually no need for machining to ensure that the object is formed to the desired net size and shape. CLM is a variant of extrusion-type rapid prototyping, in which a model or prototype of a solid object is built up by controlled extrusion of a polymeric or other material through an orifice that is translated to form patterned layers. The second layer is deposited on top of the first layer, the third layer is deposited on top of the second layer, and so forth, until the stack of layers reaches the desired final thickness and shape. The elements of CLM include (1) preparing a matrix resin in a form in which it will solidify subsequently, (2) mixing the fibers and matrix material to form a continuous pre-impregnated tow (also called "towpreg"), and (3) dispensing the pre-impregnated tow from a nozzle onto a base while moving the nozzle to form the dispensed material into a patterned layer of controlled thickness. When the material deposited into a given layer has solidified, the material for the next layer is deposited and patterned similarly, and so forth, until the desired overall object has been built up as a stack of patterned layers. Preferably, the deposition apparatus is controlled by a computer-aided design (CAD) system. The basic CLM concept can be adapted to the fabrication of parts from a variety of matrix materials. It is conceivable that a CLM apparatus could be placed at a remote location on Earth or in outer space where (1) spare parts are expected to be needed but (2) it would be uneconomical or impractical to store a full inventory of spare parts. A wide variety of towpregs could be prepared and stored on spools until needed. Long-shelf-life towpreg materials suitable for such use could include thermoplastic-coated carbon fibers and metal-coated SiC fibers. When a spare part was needed, the part could be fabricated by CLM under control by a CAD data file; thus, the part could be built automatically, at the scene, within hours or minutes.

Wang, C. Jeff↗

Local Analysis-Test Correlation Of Tow-Steered Composite Shells With Small Cutouts

The prebuckling and postbuckling behavior of two composite tow-steered shells with small cutouts is assessed using nonlinear dynamic finite element analyses and compared in detail with experimental measurements. The cylindrical shells were manufactured without cutouts using an automated fiber placement system, where the shells’ fiber orientation angles vary continuously around the shell circumference from ±10 degrees on the axially stiff crown and keel, to ±45 degrees on the shear-stiff sides. The first shell with overlaps has laminate thickness variations on the crown and keel that result from application of all 24 tows during each pass of the fiber placement system. The second shell without overlaps uses the fiber placement system’s tow drop/add capability to achieve a more uniform shell wall thickness. An unreinforced cutout representing a passenger door on a commercial aircraft fuselage is machined into the side of each of the two shells. These shells with cutouts were tested in axial compression and buckled elastically in previous work. Detailed nonlinear finite element analysis results are compared with their corresponding measured local load-displacement and load-strain responses in prebuckling, at global buckling, and into a stable postbuckled state. Test data from displacement transducers, strain gages, and digital image correlation are extracted at the centers of the crown and keel, and at the middles of the top and left edges of the cutout. The overall agreement between these measured and analytical responses is excellent in prebuckling through global buckling, and very good from global buckling through postbuckling. As such, the excellent correlation observed here increases confidence in applying tow-steered composites in operational vehicles.

Composites↗

Local Analysis-Test Correlation Of Tow-Steered Composite Shells With Small Cutouts

The prebuckling and postbuckling behavior of two composite tow-steered shells with small cutouts is assessed using nonlinear dynamic finite element analyses and compared in detail with experimental measurements. The cylindrical shells were manufactured without cutouts using an automated fiber placement system, where the shells’ fiber orientation angles vary continuously around the shell circumference from ±10 degrees on the axially stiff crown and keel, to ±45 degrees on the shear-stiff sides. The first shell with overlaps has laminate thickness variations on the crown and keel that result from application of all 24 tows during each pass of the fiber placement system. The second shell without overlaps uses the fiber placement system’s tow drop/add capability to achieve a more uniform shell wall thickness. An unreinforced cutout representing a passenger door on a commercial aircraft fuselage is machined into the side of each of the two shells. These shells with cutouts were tested in axial compression and buckled elastically in previous work. Detailed nonlinear finite element analysis results are compared with their corresponding measured local load-displacement and load-strain responses in prebuckling, at global buckling, and into a stable postbuckled state. Test data from displacement transducers, strain gages, and digital image correlation are extracted at the centers of the crown and keel, and at the middles of the top and left edges of the cutout. The overall agreement between these measured and analytical responses is excellent in prebuckling through global buckling, and very good from global buckling through postbuckling. As such, the excellent correlation observed here increases confidence in applying tow-steered composites in operational vehicles.

Composites↗

ISM In-Space Manufacturing

In-Space Manufacturing (ISM), managed out of the Marshall Space Flight Center, is working to provide capabilities for on-demand sustainable manufacturing of mechanical and electrical components during NASA Exploration Missions (transit and on-surface). ISM continues to pursue the development and evaluation of new technologies that will be applied in space for years to come.

Zach Courtright↗

Testing and Analyses of Advanced Composite Tow-Steered Shells with Cutouts

The structural response of two composite tow-steered shells with small cutouts in end compression is assessed using analyses and experimental measurements. The cylindrical shells were manufactured without cutouts using an automated fiber placement system, where the shells’ fiber orientation angles vary continuously around the shell circumference from ±10 degrees on the axially stiff crown and keel, to ±45 degrees on the shear-stiff sides. The first shell with overlaps has laminate thickness variations on the crown and keel that result from application of all 24 tows during each pass of the fiber placement system. The second shell without overlaps uses the fiber placement system’s tow drop/add capability to achieve a more uniform shell wall thickness. These shells without cutouts were tested in axial compression and buckled elastically. An unreinforced cutout representative of a passenger door on a commercial aircraft fuselage is machined into one side of each shell. Results from nonlinear finite element analysis are compared with their corresponding load, displacement, and strain measurements in prebuckling through stable postbuckling. Results from tests and analyses of shells with large cutouts are also discussed. The very good agreement observed in this study increases confidence in applying tow-steered composites to operational vehicles.

Tow-Steered↗

Continuous Liquid–Liquid Extraction and in-Situ Membrane Separation of Miscible Liquid Mixtures

Separation operations are critical across a wide variety of manufacturing industries and account for about one quarter of all in-plant energy consumption in the United States. Conventional liquid-liquid separation operations require either thermal or chemical treatment, both of which have a large environmental impact and carbon footprint. Consequently, there is a great need to develop sustainable, clean methodologies for separation of miscible liquid mixtures. The greatest opportunities to achieve this lie in replacing high-energy separation operations (e.g., distillation) with low-energy alternatives such as liquid-liquid extraction. One of the primary design challenges in liquid-liquid extraction is to maximize the interfacial area between two immiscible (e.g., polar and non-polar) liquids for efficient mass transfer. However, this often involves energy-intensive methods including ultrasonication, pumping the feed and the extractant through packed columns with high tortuosity, or using a supercritical fluid as an extractant. Emulsifying the feed and the extractant, especially with a surfactant, offers a large interfacial area, but subsequent separation of emulsions can be energy-intensive and expensive. Thus, emulsions are typically avoided in conventional extraction operations. Herein, we discuss a novel, easily scalable, platform separation methodology termed CLEANS (Continuous Liquid-liquid Extraction And iN-situ membrane Separation). CLEANS integrates emulsion-enhanced extraction with continuous, gravity-driven, membrane-based separation of emulsions into a single unit operation. Furthermore, our results demonstrate that the addition of a surfactant and emulsification significantly enhance extraction (by > 250% in certain cases), even for systems where the best extractants for miscible liquid mixtures are known. Utilizing the CLEANS methodology, we demonstrate continuous separation of a wide range of miscible liquid mixtures, including soluble organic molecules from oils, alcohols from esters, and even azeotropes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Enabling Deformable and Stretchable Batteries

Abstract Deformable energy storage devices are needed to power next‐generation wearable electronics that interface intimately with human skin. Currently, deformable energy storage devices demonstrate poor performance compared to their rigid lithium‐ion counterparts, forcing wearable manufacturers to design their devices around bulky battery compartments. However, technological advances to create deformable batteries at the component and device level have yielded continuous improvement in stretchable batteries over the last five years. In this Essay, the major strategies at the component and device level that have been successfully employed to create stretchable batteries are reviewed. The outstanding challenges facing deformable energy storage are also discussed, namely, energy density, packaging, delamination, device integration, and manufacturing. This Essay will give researchers who are interested in contributing to the development of deformable batteries a cursory understanding of the most successful strategies to date, and provide insights into the most important directions to pursue in the future.

Mackanic, David G.↗

Design Analysis and Thermo-Mechanical Fatigue of a Polyimide Composite for Combustion Chamber Support

Polyimide composites are being evaluated for use in lightweight support structures designed to preserve the ideal flow geometry within thin shell combustion chambers of future space launch propulsion systems. Principles of lightweight design and innovative manufacturing techniques have yielded a sandwich structure with an outer face sheet of carbon fiber polyimide matrix composite. While the continuous carbon fiber enables laminated skin of high specific stiffness; the polyimide matrix materials ensure that the rigidity and durability is maintained at operation temperatures of 316 C. Significant weight savings over all metal support structures are expected. The protypical structure is the result of ongoing collaboration, between Boeing and NASA-GRC seeking to introduce polyimide composites to the harsh environmental and loads familiar to space launch propulsion systems. Design trade analyses were carried out using relevant closed form solutions, approximations for sandwich beams/panels and finite element analysis. Analyses confirm the significant thermal stresses exist when combining materials whose coefficients of thermal expansion (CTEs) differ by a factor of about 10 for materials such as a polymer composite and metallic structures. The ramifications on design and manufacturing alternatives are reviewed and discussed. Due to stringent durability and safety requirements, serious consideration is being given to the synergistic effects of temperature and mechanical loads. The candidate structure operates at 316 C, about 80% of the glass transition temperature T(sub g). Earlier thermomechanical fatigue (TMF) investigations of chopped fiber polyimide composites made this near to T(sub g), showed that cyclic temperature and stress promoted excessive creep damage and strain accumulation. Here it is important to verify that such response is limited in continuous fiber laminates.

Thesken, J. C.↗

Solid Freeform Fabrication of Continuous Fiber Reinforced Composites for Propulsion Applications

For propulsion related applications, materials must be able to demonstrate excellent ablation and oxidation resistance at temperature approaching 3500'C, adequate load bearing capabilities, non-catastrophic failure modes, and ability to withstand transient thermal shock. A potential list of propulsion-material property requirements includes, low density, high elastic modulus, low thermal-expansion coefficient, high thermal conductivity, excellent erosion and oxidation/corrosion resistance, and flaw-insensitivity. In many cases, they will also need to be able to be joined, survive thermal cycling and multi-axial stress states, and for reusable applications, the materials must maintain the above attributes after prolonged exposure to extremely harsh chemical environments. The final and possibly most important attribute for these materials are the need to be lower cost and readily available in large quantities. Recently, Advanced Ceramics Research, Inc. (ACR) has developed low cost, flexible- manufacturing processes for Zr & Hf-based carbon fiber reinforced composites, materials with good oxidation and ablation resistance up to 3500 C. This process, called Continuous Composite Co-extrusion (C(sup 3)), incorporates carbon fibers to fabricate 'in-situ' carbide and boride-matrix/carbon fiber composites. This is a variation of ACR's manufacturing process for low-cost structural ceramic materials called Fibrous Monoliths With carbon fiber reinforcements. Fibrous Monolithic materials have a distinct fibrous texture, consist of intertwined cells of a primary phase, separated by cell boundaries of a tailored secondary phase and show very high fracture energies, damage tolerance, and graceful failure. Since they are monolithic powder based composites-, they can be manufactured by conventional powder processing techniques using inexpensive raw materials. This combination of high performance and low cost is a breakthrough that could enable wider application of ceramics in high temperature applications. Typical volume fractions of the two phases are 80 to 95% for the cell phase and 5 to 20% for the interpenetrating cell boundary phase. ACR is currently developing an innovative solid freeform form fabrication (SFF) approach to produce Hf and Zr based ceramic composite components reinforced with continuous carbon fiber tows for critical structural components such as tubes and blisks. The process is simple, robust and will be widely applicable to a number of material systems. This technique was originally developed at the University of Delaware Center for Composite Materials (UD-CCM) for rapid fabrication of polymer matrix composites by a technique called automated tow placement or ATP. The current process is being developed in collaboration with UD-CCM. The paper will detail the freeform fabrication process to create low-cost ceramic fiber reinforced composites for high-temperature applications. The results of mechanical properties and microstructural characterization will be presented, together with examples of complex shapes and parts. It is believed that the process will be able to create complex shaped parts for propulsion applications at an order of magnitude lower cost than current CVI and PIP process.

Vaidyanathan, R.↗

Solid Free-Form Fabrication of Continuous Fiber Reinforced Composites for Propulsion Application

For propulsion related applications, materials must be able to demonstrate excellent ablation and oxidation resistance at temperature approaching 3500 C, adequate load bearing capabilities, non-catastrophic failure modes, and ability to withstand transient thermal shock. A potential list of propulsion-material property requirements includes, low density, high elastic modulus, low thermal-expansion coefficient, high thermal conductivity, excellent erosion and oxidation/corrosion resistance, and flaw-insensitivity. In many cases, they will also need to be able to be joined, survive thermal cycling and multi-axial stress states, and for reusable applications, the materials must maintain the above attributes after prolonged exposure to extremely harsh chemical environments. The final and possibly most important attribute for these materials are the need to be lower cost and readily available in large quantities. Recently, Advanced Ceramics Research, Inc. (ACR) has developed low cost, flexible-manufacturing processes for Zr & Hf-based carbon fiber reinforced composites, materials with good oxidation and ablation resistance up to 3500 C. This process, called Continuous Composite Co-extrusion (C(sup 3)), incorporates carbon fibers to fabricate 'in-situ' carbide and boride-matrix/carbon fiber composites. M is a variation of ACR's manufacturing process for low-cost structural ceramic materials called Fibrous Monoliths with carbon fiber reinforcements. Fibrous Monolithic materials have a distinct fibrous texture, consist of intertwined cells of a primary phase, separated by cell boundaries of a tailored secondary phase and show very high fracture energies, damage tolerance, and graceful failure. Since they are monolithic powder based composites; they can be manufactured by conventional powder processing techniques using inexpensive raw materials. This combination of high performance and low cost is a breakthrough that could enable wider application of ceramics in high temperature applications. Typical volume fractions of the two phases are 80 to 95% for the cell phase and 5 to 20% for the interpenetrating cell boundary phase. ACR is currently developing an innovative solid freeform form fabrication (SFF) approach to produce Hf and Zr based ceramic composite components reinforced with continuous carbon fiber tows for critical structural components such as tubes and blisks. The process is simple, robust and will be widely applicable to a number of material systems. This technique was originally developed at the University of Delaware Center for Composite Materials (UD-CCM) for rapid fabrication of polymer matrix composites by a technique called automated tow placement or ATP. The current process is being developed in collaboration with UD-CCM. The paper will detail the freeform fabrication process to create low-cost ceramic fiber reinforced composites for high-temperature applications. The results of mechanical properties and microstructural characterization will be presented, together with examples of complex shapes and parts. It is believed that the process will be able to create complex shaped parts for propulsion applications at an order of magnitude lower cost than current CVI and PIP processes.

Vaidyanathan, R.↗

Rapid Bacterial Testing for Spacecraft Water

Evaluations of the fluorogenic stains and probes will continue. E. coli 0157:H7 will be used as the reference strain for optimizing protocols. We anticipate the continued use of the fluorescent antibodies (TRITC and FITC labeled) in conjunction with CTC, Rhl23, DiBAC4(3), DAPI and acridine orange. Chemunex, the manufacturer of the ChemScan analyzer system, also makes a fluorogenic probe, Chemchrome B, which will be incorporated into the suite of probes to evaluate once their system is on site. Regardless of the combination of stains and probes all will be evaluated on membrane filters. Development of a FISH protocol that will be applicable to our conditions will be continued. Complimentary 16s rRNA probes to Ps. aeruginosa and currently in our laboratory will be evaluated first. Once this protocol has been adequately optimized other probes will be ordered for u a select number of other species. Currently, protocols to evaluate the effects of disinfection and the resulting lethality, injury on stain and/or probe specificity and reliability are being developed. E. coli 0157:H7 is the reference strain and chlorine the disinfectant the reference protocol is being developed around. Upon completion of this work, the resulting protocol will be extended to other species and disinfectants (e.g., iodine). Similar disinfectant experiments will then be conducted on the same species after starvation to evaluate the effects of starvation on disinfection resistance and the applicability of the stains and probes. Development of the immunomagnetic separation system will continue. Combined with the rapid methods described above, with enumeration by the ChemScan, we anticipate that this will provide a highly sensitive technique for the detection of specific, active bacteria.

Lisle, John T.↗

Tracking Volumetric Units in Modular Factories for Automated Progress Monitoring Using Computer Vision

The construction industry is increasingly adopting off-site and prefabricated methods due to advantages offered in safety, quality, and lead time. Applying industrialized methods for plant management in offsite construction factories requires the collection of large volumes of production process data, which is a tedious task when performed manually. Recent attempts to automate this process have relied on sensor-based data collection methods which are susceptible to noise, expensive, and difficult to validate. Computer vision methods, however, enable process data collection from videos without the limitations of the other sensor-based methods. This technology has not been applied for offsite construction except in very few instances and therefore, this study proposes a novel method to reliably collect the production process data using computer vision method in near real-time from widely used surveillance cameras in offsite construction. The proposed method allows the user to annotate the workstations of interest on the video as ground truths and process these areas throughout the entire video to track the units entering and leaving stations, while continuously updating a near real-time schedule of the production line. This framework was validated by implementing on the surveillance videos of the production process of modular home manufacturing in a factory. The results consistently provided 100% accuracy, after denoising, for all the videos processed including 60 h of work for a station. The developed method enables real-time tracking of station performance, which can enable continuous improvement methods for factory management and resource allocation.

computer vision↗

Roll-to-Roll Advanced Materials Manufacturing DOE Laboratory Collaboration - Early Stage R&D: Phase 2 and FY21 (Final Report)

R2R processing is used to manufacture a wide range of products for various applications which span many industrial business sectors. The overall R2R methodology has been in use for decades and this continuous technique traditionally involves deposition of material(s) onto substrates or membranes that are on moving webs, carriers or other continuous belt-fed or conveyor-based processes that enable successive steps to build a final product. Established methods that typify R2R processing include tape casting, silk-screen printing, reel-to-reel vacuum deposition/coating, and R2R lithography. Products supported by R2R manufacturing include micro-electronics, electro-chromic window films, PVs, fuel cells for energy conversion, battery electrodes and electrolytes for energy storage, and barrier and membrane materials for decarbonization and air and water filtration. Due to innovation in materials and process equipment, high-quality yet very low-cost multilayer technologies have the potential to be manufactured on a very cost-competitive basis. To move energy-related products from high-cost niche applications to the commercial sector, the means must be available to enable manufacture of these products in a cost-competitive manner. Fortunately, products such as fuel cells, thin- and mid-film PVs, batteries, electrochromic and piezoelectric films, water separation membranes, and other energy saving technologies readily lend themselves to manufacture using R2R approaches. However, more early-stage research is needed to solve the challenge of linking the materials (particles, polymers, solvents, additives) used in ink and slurry formulations and the coating and heated drying processes to the ultimate performance of the final R2R product, especially for a process that uses multiple layers of deposition to achieve the end product.

36 MATERIALS SCIENCE↗

Operation, Manufacturing, and Supply Chain of Lithium-ion Batteries for Electric Vehicles

The US Department of Energy (DOE) has a rich history of funding key innovations in batteries through multiple programs, including the Energy Efficiency and Renewable Energy programs sponsored by the Vehicle Technologies Office and Advanced Manufacturing Office. These DOE-sponsored innovations have been critical in lowering the cost of lithium-ion batteries to less than $160/kWh and increasing their energy density to more than 250 Wh/kg, enhancing the nation’s electrification system and achieving higher degrees of decarbonization. These investments continue to be crucial for positioning the United States as the hub for the most cumulative battery R&D programs worldwide. However, major breakthroughs in battery manufacturing are still needed to enable an electrified future evolving to predominantly incorporate rechargeable lithium-ion batteries. This will require a strong battery manufacturing base that will not only enable cutting-edge advancements in materials and manufacturing sciences but will also allow the United States to become a world leader in this fast-growing area. This review aims at supporting DOE’s Advanced Technology Vehicle Manufacturing Loan Program to give technology background and information that can be used to develop the basis for loan topics and evaluate battery applications. Such a program can represent a significant stride toward reinforcing the US position in advanced manufacturing by introducing artificial intelligence, machine learning, and sensing and smart controls to facilitate, expedite, and lead the battery industry by 2030.

25 ENERGY STORAGE↗

Optimized Carbon Fiber Composites in Wind Turbine Blade Design: Follow-On Studies

This project has identified opportunities to bring further reductions in the mass and cost of modern wind turbine blades through the use of alternative material systems and manufacturing processes. The fiber reinforced polymer material systems currently used by the wind industry have stagnated as the technology continues to mature and as a means to reduce risk while introducing new products with continually increasing blade lengths. However, as blade lengths continue to increase, the challenge of controlling blade mass becomes even more critical to enabling the associated levelized cost of energy reductions. Stiffer and stronger reinforcement fibers can help to resolve the challenges of meeting the loading demands while limiting the increase in weight, but these materials are substantially more expensive than the traditional E-glass fiber systems. One goal of this project and associated work is to identify pathways that improve the cost-effectiveness of carbon fiber such that it is the reinforcement of choice in the primary structural elements of wind blades. The use of heavy-tow textile carbon fiber material systems has been shown to reduce the blade mass by 30-31% when used in the spar cap and by up to 7% when used in edgewise reinforcement. A pultrusion cost model was developed to enable a material cost comparison that includes an accurate estimate of the intermediate manufacturing step of pultrusion for the carbon fiber composite. Material cost reductions were revealed in most cases for the heavy-tow textile carbon fiber compared to infused fiberglass. The use of carbon fiber in the edgewise reinforcement produced the most notable material cost reduction of 33% for the heavy-tow textile carbon fiber. The mass and cost savings observed when using carbon fiber in edgewise reinforcement demonstrate a clear opportunity of this design approach. A carbon fiber conversion cost model was expanded to include a characterization of manufacturing costs when using advanced conversion processes with atmospheric plasma oxidation. This manufacturing approach was estimated to reduce the cost of carbon fiber material systems by greater than 10% and can be used with textile carbon systems or traditional carbon fiber precursors. The pultrusion cost model was also used to assess the opportunity for using pultruded fiberglass in wind blades, studying conventional E-glass fiber reinforcement. When using pultruded fiberglass as the spar cap material for two design classifications, the blade weight was reduced by 6% and 9% compared to infused fiberglass. However, due to the relatively large share of the pultrusion manufacturing cost compared to fiber cost, the spar cap material cost increased by 12% and 7%. When considering the system benefits of reduced blade mass and potentially lower blade manufacturing costs for pultruded composites, there may be opportunity for pultruded E-glass in wind blade spar caps, but further studies are needed. There is a clearer outcome for using pultruded fiberglass in the edgewise reinforcement where it resulted in a blade mass reduction of 2% and associated reinforcement material cost reduction of 1% compared to infused E-glass. The use of higher performing glass fibers, such as S-glass and H-glass systems, will produce greater mass savings but a study is needed to assess the cost implications for these more expensive systems. The most likely opportunity for these high-performance glass fibers is in the edgewise reinforcement, where the increased strength will reduce the damage accumulation of this fatigue-driven component. The blade design assessments in this project characterize the controlling material properties for the primary structural components in the flapwise and edgewise directions for modern wind blades. The observed trends with low and high wind speed turbine classifications for carbon and glass fiber reinforced polymer systems help to identify where cost reductions are needed, and where improvements in mechanical properties would help to reduce the material demands.

17 WIND ENERGY↗

Proton Exchange Membrane Fuel Cell Engineering Model Powerplant. Test Report: Benchmark Tests in Three Spatial Orientations

Proton exchange membrane (PEM) fuel cell technology is the leading candidate to replace the aging alkaline fuel cell technology, currently used on the Shuttle, for future space missions. This test effort marks the final phase of a 5-yr development program that began under the Second Generation Reusable Launch Vehicle (RLV) Program, transitioned into the Next Generation Launch Technologies (NGLT) Program, and continued under Constellation Systems in the Exploration Technology Development Program. Initially, the engineering model (EM) powerplant was evaluated with respect to its performance as compared to acceptance tests carried out at the manufacturer. This was to determine the sensitivity of the powerplant performance to changes in test environment. In addition, a series of tests were performed with the powerplant in the original standard orientation. This report details the continuing EM benchmark test results in three spatial orientations as well as extended duration testing in the mission profile test. The results from these tests verify the applicability of PEM fuel cells for future NASA missions. The specifics of these different tests are described in the following sections.

Loyselle, Patricia↗

Enhanced Catalyst Durability and Sulfur Tolerance by Atomic Layer Deposition (CRADA Final Report)

This CRADA advanced the use of atomic layer deposition (ALD) catalyst coatings to improve sulfur tolerance and demonstrate improved catalyst durability for biomass conversion chemistries. This project leveraged National Laboratory and industry expertise for ALD catalyst coating development between NREL, ALD NanoSolutions, Inc. ("ALD NanoSolutions"), and Johnson Matthey PLC ("Johnson Matthey"). To better understand the role of ALD coatings on catalyst activity and durability, a joint experimental and computational effort combined bench-scale ALD catalyst synthesis, material characterization, catalyst testing, and modeling of catalyst surface energetics. In addition, to demonstrate the commercial relevance of this technology, scaled ALD coated catalysts were subjected to continuous testing and accelerated aging to validate performance gains. Results were used to inform ALD catalyst coating manufacturing cost models, as well as biobased chemical process cost models.

09 BIOMASS FUELS↗