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At least 433 records · Page 24

Integrated design and manufacturing for the high speed civil transport (a combined aerodynamics/propulsion optimization study)

This report documents the efforts of a Georgia Tech High Speed Civil Transport (HSCT) aerospace student design team in completing a design methodology demonstration under NASA's Advanced Design Program (ADP). Aerodynamic and propulsion analyses are integrated into the synthesis code FLOPS in order to improve its prediction accuracy. Executing the integrated product and process development (IPPD) methodology proposed at the Aerospace Systems Design Laboratory (ASDL), an improved sizing process is described followed by a combined aero-propulsion optimization, where the objective function, average yield per revenue passenger mile ($/RPM), is constrained by flight stability, noise, approach speed, and field length restrictions. Primary goals include successful demonstration of the application of the response surface methodolgy (RSM) to parameter design, introduction to higher fidelity disciplinary analysis than normally feasible at the conceptual and early preliminary level, and investigations of relationships between aerodynamic and propulsion design parameters and their effect on the objective function, $/RPM. A unique approach to aircraft synthesis is developed in which statistical methods, specifically design of experiments and the RSM, are used to more efficiently search the design space for optimum configurations. In particular, two uses of these techniques are demonstrated. First, response model equations are formed which represent complex analysis in the form of a regression polynomial. Next, a second regression equation is constructed, not for modeling purposes, but instead for the purpose of optimization at the system level. Such an optimization problem with the given tools normally would be difficult due to the need for hard connections between the various complex codes involved. The statistical methodology presents an alternative and is demonstrated via an example of aerodynamic modeling and planform optimization for a HSCT.

Baecher, Juergen↗

Regulation of Dynamical Systems to Optimal Solutions of Semidefinite Programs: Algorithms and Applications to AC Optimal Power Flow

This paper considers a collection of networked nonlinear dynamical systems, and addresses the synthesis of feedback controllers that seek optimal operating points corresponding to the solution of pertinent network-wide optimization problems. Particular emphasis is placed on the solution of semidefinite programs (SDPs). The design of the feedback controller is grounded on a dual e-subgradient approach, with the dual iterates utilized to dynamically update the dynamical-system reference signals. Global convergence is guaranteed for diminishing stepsize rules, even when the reference inputs are updated at a faster rate than the dynamical-system settling time. The application of the proposed framework to the control of power-electronic inverters in AC distribution systems is discussed. The objective is to bridge the time-scale separation between real-time inverter control and network-wide optimization. Optimization objectives assume the form of SDP relaxations of prototypical AC optimal power flow problems.

24 POWER TRANSMISSION AND DISTRIBUTION↗

The vehicle design evaluation program - A computer-aided design procedure for transport aircraft

The vehicle design evaluation program is described. This program is a computer-aided design procedure that provides a vehicle synthesis capability for vehicle sizing, external load analysis, structural analysis, and cost evaluation. The vehicle sizing subprogram provides geometry, weight, and balance data for aircraft using JP, hydrogen, or methane fuels. The structural synthesis subprogram uses a multistation analysis for aerodynamic surfaces and fuselages to develop theoretical weights and geometric dimensions. The parts definition subprogram uses the geometric data from the structural analysis and develops the predicted fabrication dimensions, parts material raw stock buy requirements, and predicted actual weights. The cost analysis subprogram uses detail part data in conjunction with standard hours, realization factors, labor rates, and material data to develop the manufacturing costs. The program is used to evaluate overall design effects on subsonic commercial type aircraft due to parameter variations.

Oman, B. H.↗

Universal Polarization Transformations: Spatial Programming of Polarization Scattering Matrices Using a Deep Learning‐Designed Diffractive Polarization Transformer

Abstract Controlled synthesis of optical fields having nonuniform polarization distributions presents a challenging task. Here, a universal polarization transformer is demonstrated that can synthesize a large set of arbitrarily‐selected, complex‐valued polarization scattering matrices between the polarization states at different positions within its input and output field‐of‐views (FOVs). This framework comprises 2D arrays of linear polarizers positioned between isotropic diffractive layers, each containing tens of thousands of diffractive features with optimizable transmission coefficients. After its deep learning‐based training, this diffractive polarization transformer can successfully implement N i N o = 10 000 different spatially‐encoded polarization scattering matrices with negligible error, where N i and N o represent the number of pixels in the input and output FOVs, respectively. This universal polarization transformation framework is experimentally validated in the terahertz spectrum by fabricating wire‐grid polarizers and integrating them with 3D‐printed diffractive layers to form a physical polarization transformer. Through this set‐up, an all‐optical polarization permutation operation of spatially‐varying polarization fields is demonstrated, and distinct spatially‐encoded polarization scattering matrices are simultaneously implemented between the input and output FOVs of a compact diffractive processor. This framework opens up new avenues for developing novel devices for universal polarization control and may find applications in, e.g., remote sensing, medical imaging, security, material inspection, and machine vision.

Optical neural networks↗

Adaptable structural synthesis using advanced analysis and optimization coupled by a computer operating system

A finite element program is linked with a general purpose optimization program in a 'programing system' which includes user supplied codes that contain problem dependent formulations of the design variables, objective function and constraints. The result is a system adaptable to a wide spectrum of structural optimization problems. In a sample of numerical examples, the design variables are the cross-sectional dimensions and the parameters of overall shape geometry, constraints are applied to stresses, displacements, buckling and vibration characteristics, and structural mass is the objective function. Thin-walled, built-up structures and frameworks are included in the sample. Details of the system organization and characteristics of the component programs are given.

Sobieszczanski-Sobieski, J.↗

A root locus based flutter synthesis procedure

An efficient generalized constraint is proposed in the context of a nonlinear mathematical programming approach for the minimum weight design of wing structures for flutter considerations. The approach is based on a root locus analysis procedure that is better suited for flutter redesign than the conventionally used V-g method. The proposed flutter constraint does not require an actual computation of the flutter speed, allows prescription of meaningful margins of safety in the optimized design and lends itself to elegant computation of sensitivity information. The approach is implemented and results presented for representative structural models.

Hajela, P.↗

A research program in active control/aeroelasticity in the JIAFS at NASA Langley Research Center

A control law synthesis methodology for multifunctional active control system to satisfy root-mean-square load and response constraints as well as to meet stability robustness requirements at plant input and output was developed. Modern control theory, singular value analysis and optimization techniques were utilized. All stability and response derivative expressions were derived analytically for sensitivity study. The software is incorporated as an update to the AB/LAD general control design software package PADLOCS.

Whitesides, J. L.↗

Atomically Precise Membranes for the Separation of Gases

Industrial separations require enormous amounts of energy, accounting for approximately half the industrial energy use and 10–15% of the total energy consumption. Distillation alone accounts for about half the energy demand for industrial separations. If these processes could be replaced by an energy-efficient membrane separation process, this energy demand could be reduced by 90%. However, although some membrane processes have made inroads into thermal distillation, for membrane-based separations to replace the distillation process to a far more significant and practical level, new membranes with higher robustness, selectivity, and flux still need be developed. In this membrane development program, we leveraged Temple University’s prior work in spiroligomers to develop robust membrane structures. These structures can be formed into atomically precise pores by controlling the chemical synthesis and the oligomer building blocks to first build precisely controlled macrocycles and then subsequently crosslinking these macrocycles to produce a membrane. Furthermore, through the highly controllable chemistry of our molecular building blocks, not only can we integrate pores with highly controllable and reproducible size and morphology, but we can also target internal functionalization. By using a range of scalable membrane synthesis approaches, combined with control of each and every pores internal chemistry and molecular conformation we can achieve membrane structures that can display the ultimate in high selectivity and permeance. The Mainstream-Temple University membranes can be designed to achieve ultra-selective separations based on the key factors of molecular size, shape, and functionality. In our approach to fabricate scalable atomically precise membranes, we used our molecular Lego nanostructures. We demonstrated an approach to create atomically precise pores within the membrane with pores that are the dimensions of the molecule we are trying to separate. Moreover, in addition to controlling the morphology of the membrane structure by controlling the size of every pore, we can also decorate every pore with precisely targeted and placed functional groups. These accurately placed functional groups can provide selective binding to molecules and provide enhanced selectivity via a facilitated transport mechanism. In Phase II, the Mainstream-Temple University team demonstrated the scalable synthesis of oligomers and the ability to control the pore internal and external functionality, or chemistry, to allow the fabrication of a thin-film membrane. The initial steps of the spiroligomer synthesis to produce the two key bis-amino enantiomer building blocks were scaled from the gram scale to the kilogram scale, obtaining 25 kg of the materials by transferring the procedure to a toll manufacturer. Finally, we successfully optimized the fabrication of these macrocycles into robust membranes. We successfully transitioned from a laboratory based, hard-to-scale Langmuir trough synthesis to a highly scalable, roll-to-roll applicable, interfacial polymerization process. During this Phase II program, we established a platform of atomically precise membranes where our highly controllable, atomically precise macrocycles served as a scaffold with precisely and uniformly controlled pores. Furthermore, this layer can be tailored to accommodate a diverse range of functional groups, which both further controlled the pore size to enhance the sieving effect as well as imparting precisely controlled targeted selectivity through biomimetic molecular interactions. In this Phase II, we established and scaled up a platform approach to both tune the pore size and chemistry as well as scale it to produce membranes that can be applied to a wide range of industries. In future development, the project team expects to scale up both the macrocycle building block production and interfacial polymerization process to produce the atomically precise membrane with targeted pore sizes and pore chemistries.

36 MATERIALS SCIENCE↗

Fuel Salt Synthesis for the Molten Chloride Reactor Experiment: Scale-up, Operations, and Production Update

Over the previous 5 years, Idaho National Laboratory (INL) has been working with Southern Co. and TerraPower on the Advanced Reactor Demonstration Program (ARDP) funded Molten Chloride Reactor Experiment (MCRE) project. As part of this effort, INL has developed a fuel synthesis process to produce the NaCl-UCl3 fuel salt that MCRE will need for operation. Dr. Phillips will present on process development and scale-up testing and results, as well as provide an update on the current status of fuel production for MCRE. To date, the fuel synthesis process has been demonstrated at full scale using depleted uranium, and the equipment necessary for production of the fuel for MCRE has been installed in the Fuel Manufacturing Facility (FMF) at the INL’s Materials and Fuels Complex (MFC). The NaCl-UCl3 produced to-date has been shown to be of 99.99% purity or greater, and be within tolerance for all relevant parameters. Overall process efficiency in terms of uranium utilization has been demonstrated to be above 90%. The synthesis operation has also been shortened to allow for completion of the reaction within a single 10 hour working shift. Consequently, the process developed is expected to be capable of meeting all project objectives for efficiency, purity, scale, and scheduling. Production of NaCl-UCl3 fuel salt for MCRE is projected to begin during the Summer of 2025.

11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Programmed cell death regulator BAP2 is required for IRE1-mediated unfolded protein response in Arabidopsis

Environmental and physiological situations can challenge the balance between protein synthesis and folding capacity of the endoplasmic reticulum (ER) and cause ER stress, a potentially lethal condition. The unfolded protein response (UPR) restores ER homeostasis or actuates programmed cell death (PCD) when ER stress is unresolved. The cell fate determination mechanisms of the UPR are not well understood, especially in plants. Here, we integrate genetics and ER stress profiling with natural variation and quantitative trait locus analysis of 350 natural accessions of the model species Arabidopsis thaliana . Our analyses implicate a single nucleotide polymorphism to the loss of function of the general PCD regulator BON-ASSOCIATED PROTEIN2 (BAP2) in UPR outcomes. We establish that ER stress-induced BAP2 expression is antagonistically regulated by the UPR master regulator, inositol-requiring enzyme 1 (IRE1), and that BAP2 controls adaptive UPR amplitude in ER stress and ignites pro-death mechanisms in conditions of UPR insufficiency.

59 BASIC BIOLOGICAL SCIENCES↗

An acceptable role for computers in the aircraft design process

Some of the reasons why the computerization trend is not wholly accepted are explored for two typical cases: computer use in the technical specialties and computer use in aircraft synthesis. The factors that limit acceptance are traced in part, to the large resources needed to understand the details of computer programs, the inability to include measured data as input to many of the theoretical programs, and the presentation of final results without supporting intermediate answers. Other factors are due solely to technical issues such as limited detail in aircraft synthesis and major simplifying assumptions in the technical specialties. These factors and others can be influenced by the technical specialist and aircraft designer. Some of these factors may become less significant as the computerization process evolves, but some issues, such as understanding large integrated systems, may remain issues in the future. Suggestions for improved acceptance include publishing computer programs so that they may be reviewed, edited, and read. Other mechanisms include extensive modularization of programs and ways to include measured information as part of the input to theoretical approaches.

Gregory, T. J.↗

Nature of Reactive Hydrogen for Ammonia Synthesis over a Ru/C12A7 Electride Catalyst

Recently, there have been renewed interests in exploring new catalysts for ammonia synthesis under mild conditions. Electride-based catalysts are among the emerging ones. Ruthenium particles supported on an electride composed of a mixture of calcium and aluminum oxides (C12A7) have attracted great attention for ammonia synthesis due to their facile ability in activating N2 under ambient pressure. However, the exact nature of the reactive hydrogen species and the role of electride support still remain elusive for this catalytic system. Here, we report for the first time that the surface-adsorbed hydrogen, rather than the hydride encaged in the C12A7 electride, plays a major role in ammonia synthesis over the Ru/C12A7 electride catalyst with the aid of in situ neutron scattering techniques. Combining in situ neutron diffraction, inelastic neutron spectroscopy, density functional theory (DFT) calculation, and temperature-programmed reactions, the results provide direct evidence for not only the presence of encaged hydrides during ammonia synthesis but also the strong thermal and chemical stability of the hydride species in the Ru/C12A7 electride. Steady state isotopic transient kinetic analysis (SSITKA) of ammonia synthesis showed that the coverage of reactive intermediates increased significantly when the Ru particles were promoted by the electride form (coverage up to 84%) of the C12A7 support rather than the oxide form (coverage up to 15%). Such a drastic change in the intermediate coverage on the Ru surface is attributed to the positive role of electride support where the H2 poisoning effect is absent during ammonia synthesis over Ru. The finding of this work has significant implications for understanding catalysis by electride-based materials for ammonia synthesis and hydrogenation reactions in general.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Development of Metal Boride/Carbide Precursors for MOCVD Applications (Office of Naval Research Research Performance Progress Report)

Annual Report for Office of Naval Research (ONR) program office. Highlights the synthetic and corresponding computational efforts surrounding the synthesis and processing of chemical precursors and their subsequent processing for formation of metal carbide products. Focus of this annual report is largely directed toward the computational effort as that manuscript is being finalized for submission.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Predicting Mission Success in Small Satellite Missions

In our global society with its increasing international competition and tighter financial resources, governments, commercial entities and other organizations are becoming critically aware of the need to ensure that space missions can be achieved on time and within budget. This has become particularly true for the National Aeronautics and Space Administration's (NASA's) Office of Space Science (OSS) which has developed their Discovery and Explorer programs to meet this need. As technologies advance, space missions are becoming smaller and more capable than their predecessors. The ability to predict the mission success of these small satellite missions is critical to the continued achievement of NASA science mission objectives. The NASA Office of Space Science, in cooperation with the NASA Langley Research Center, has implemented a process to predict the likely success of missions proposed to its Discovery and Explorer Programs. This process is becoming the basis for predicting mission success in many other NASA programs as well. This paper describes the process, methodology, tools and synthesis techniques used to predict mission success for this class of mission.

Saunders, Mark↗

Predicting Mission Success in Small Satellite Missions

In our global society with its increasing international competition and tighter financial resources, governments, commercial entities and other organizations are becoming critically aware of the need to ensure that space missions can be achieved on time and within budget. This has become particularly true for the National Aeronautics and Space Administration's (NASA) Office of Space Science (OSS) which has developed their Discovery and Explorer programs to meet this need. As technologies advance, space missions are becoming smaller and more capable than their predecessors. The ability to predict the mission success of these small satellite missions is critical to the continued achievement of NASA science mission objectives. The NASA Office of Space Science, in cooperation with the NASA Langley Research Center, has implemented a process to predict the likely success of missions proposed to its Discovery and Explorer Programs. This process is becoming the basis for predicting mission success in many other NASA programs as well. This paper describes the process, methodology, tools and synthesis techniques used to predict mission success for this class of mission.

Saunders, Mark↗

Synthesis and Single Crystals of Refractory Oxides of Lanthanides and Thorium

At the completion of this program, we can report that we developed a considerable degree of technical improvements in our ability to perform hydrothermal reactions at high temperatures and pressures. We can now routinely perform reactions at 700-750°C and 200 MPa. Currently we are in the process of exploiting this new technology synthesizing a range of exotic new materials investigating relatively poorly understood materials. Our initial efforts focused on the chemistry of rare earth oxides with tetravalent and pentavalent oxides. We recently published a study of the lanthanides with Nb 5+ and Ta 5+ ions, where we grew oxides such as RENdO 4 and RETaO 4 as high quality single crystals. These compounds were targeted as potential hosts for luminescent and scintillation materials, particularly given that they are among the densest oxide hosts and hence have good potential as absorbers for high energy radiation like X-rays and gamma rays. We also isolated a range of unusual new rare earth tantalates with very complex structures. indicating that the chemistry is very sensitive to conditions. We performed some fairly comprehensive examinations of the solid-state chemistry of rare earth ions with various tetravalent metal ions especially Si 4+ , Ge 4+ , Sn 4+ and Ti 4+ . Given the potential role of rare earth silicates in immobilizing radioactive waste elements in long-term storage, and the similarity of our hydrothermal fluids with known geological conditions, this chemistry continues to be relevant. We prepared an extensive series of new lanthanide germanates (e.g. RE 13 Ge 6 O 31 (OH), BaRE 10 (GeO 4 ) 4 O 8 ). and found that there is there is almost no overlap between the chemistry of the rare earth silicates. Stannic oxide (SnO 2 ) is much more refractory and requires higher temperatures and of mineralizer concentrations. One significant result is the growth of RE 2 Sn 2 O 7 pyrochlore single crystals. These are of interest because the rare earth stannate pyrochlores are known to display a wide range of magnetic frustration such as spin ice behavior. We grew high quality single crystals of rare earth germanate and stannate pyrochlores and this led to a collaboration with Professor Kate Ross at Colorado State. Preliminary measurements, indicate that the crystals contain no detectable defects or site disorder. Initial neutron diffraction on single crystals was performed at Oak Ridge, and more detailed experiments involving the Ross group are underway at both NIST and ORNL. This particular chemistry has turned out to be the most potentially significant work on this project and the collaborative effort with Prof. Ross is the topic of a DoE renewal project on quantum materials. Our initial foray into the hydrothermal chemistry of rare earth titanates has also been very promising and a range of cubic and polar ferroic phases of the light rare earths RE 2 Ti 2 O 7 (RE = La - Pr) in the P2 1 phase. We also discovered an interesting new phase Ce 2 Ti 4 O 11 that can have implications in heavy metal immobilization and storage. along with a series of new rare earth titanates (La 5 Ti 4 O 15 (OH) Sm 3 TiO 5 (OH) 3 and Lu 5 Ti 2 O 11 (OH) with exceptionally complex structures. One interesting sidelight has been high temperature hydrothermal chemistry terbium, including the growth of large crystals of TbO(OH). This is not a new compound but it is the first time it has been grown as large single crystals. The Tb atom density is almost as high as that in Tb 2 O 3 and has a very high Verdet constant (ca. 70), making it a very attractive candidate as a Faraday rotator. Unfortunately it is not in a cubic structure but he material is hard, stable, pure and inexpensive, so should still be an attractive Faraday oscillator. We recently received a patent on this material. We also synthesized K 2 Tb(Ge 2 O 7 ) containing stable octahedral Tb 4+ ions, which appears to be the first example of a well-characterized Tb 4+ complex. Given that Tb 4+ has been proposed as a benign surrogate for more treacherous tetravalent ions such as Cf 4+ and Bk 4+ , we think that Tb 4+ silicates can be a particularly useful study for actinide immobilization and related work. We also began reaction studies with rare earths and both ReO 2 and RuO 2 . These resulted in large single crystals of species like RE 5 Ru 2 O 12 , RE 4 Re 2 O 11 , REReO 4 and RE 2 ReO 5 . Several of these samples have already been sent to ORNL for magnetic and neutron diffraction studies.

36 MATERIALS SCIENCE↗

Thermochemical Conversion of Woody Biomass to Fuels and Chemicals Final Report

Maine and its industries identified more efficient utilization of biomass as a critical economic development issue. In Phase I of this implementation project, a research team was assembled, research equipment was implemented and expertise was demonstrated in pyrolysis, hydrodeoxygenation of pyrolysis oils, catalyst synthesis and characterization, and reaction engineering. Phase II built upon the infrastructure to innovate reaction pathways and process engineering, and integrate new approaches for fuels and chemical production within pulp and paper and other industries within the state. This research cluster brought together chemists, engineers, physicists and students from the University of Maine, Bates College, and Bowdoin College. The project developed collaborations with Oak Ridge National Laboratory and Brookhaven National Laboratory. The specific research projects within this proposal were of critical interest to the DoE - in particular the biomass program within EERE and the catalysis/chemical transformations program within BES. Scientific and Technical Merit highlights of this project included: (1) synthesis and physical characterization of novel size-selective catalyst/supports using engineered mesoporous (1-10 nm diameter pores) materials, (2) advances in fundamental knowledge of novel support/ metal catalyst systems tailored for pyrolysis oil upgrading, (3) a microcalorimetric sensing technique, (4) improved methods for pyrolysis oil characterization, (5) production and characterization of woody biomass-derived pyrolysis oils, (6) development of two new patented bio oil pathways: thermal deoxygenation (TDO) and formate assisted pyrolysis (FASP), and (7) technoeconomics of pyrolysis of Maine forest biomass. This research cluster has provided fundamental knowledge to enable and assess pathways to thermally convert biomass to hydrocarbon fuels and chemicals.

09 BIOMASS FUELS↗

Prenatal ethanol exposure-induced adrenal developmental abnormality of male offspring rats and its possible intrauterine programming mechanisms

Fetal adrenal developmental status is the major determinant of fetal tissue maturation and offspring growth. We have previously proposed that prenatal ethanol exposure (PEE) suppresses fetal adrenal corticosterone (CORT) synthesis. Here, we focused on PEE-induced adrenal developmental abnormalities of male offspring rats before and after birth, and aimed to explore its intrauterine programming mechanisms. A rat model of intrauterine growth retardation (IUGR) was established by PEE (4 g/kg·d). In PEE fetus, increased serum CORT concentration and decreased insulin-like growth factor 1 (IGF1) concentration, with lower bodyweight and structural abnormalities as well as a decreased Ki67 expression (proliferative marker), were observed in the male fetal adrenal cortex. Adrenal glucocorticoid (GC)-metabolic activation system was enhanced while gene expression of IGF1 signaling pathway with steroidogenic acute regulatory protein (StAR), 3β-hydroxysteroid dehydrogenase (3β-HSD) was decreased. Furthermore, in the male adult offspring of PEE, serum CORT level was decreased but IGF1 was increased with partial catch-up growth, and Ki67 expression demonstrated no obvious change. Adrenal GC-metabolic activation system was inhibited, while IGF1 signaling pathway and 3β-HSD was enhanced with the steroidogenic factor 1 (SF1), and StAR was down-regulated in the adult adrenal. Based on these findings, we propose a “two-programming” mechanism for PEE-induced adrenal developmental toxicity: “the first programming” is a lower functional programming of adrenal steroidogenesis, and “the second programming” is GC-metabolic activation system-related GC-IGF1 axis programming. - Highlights: • Prenatal ethanol exposure induces adrenal developmental abnormality in offspring rats. • Prenatal ethanol exposure induces intrauterine programming of adrenal steroidogenesis. • Intrauterine GC-IGF1 axis programming might mediate adrenal developmental abnormality.

60 APPLIED LIFE SCIENCES↗