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At least 1,549 records · Page 86

All sources NASA NTRS DOE OSTI

NASA NTRS1996

Design Methodology for Multi-Element High-Lift Systems on Subsonic Civil Transport Aircraft

The choice of a high-lift system is crucial in the preliminary design process of a subsonic civil transport aircraft. Its purpose is to increase the allowable aircraft weight or decrease the aircraft's wing area for a given takeoff and landing performance. However, the implementation of a high-lift system into a design must be done carefully, for it can improve the aerodynamic performance of an aircraft but may also drastically increase the aircraft empty weight. If designed properly, a high-lift system can improve the cost effectiveness of an aircraft by increasing the payload weight for a given takeoff and landing performance. This is why the design methodology for a high-lift system should incorporate aerodynamic performance, weight, and cost. The airframe industry has experienced rapid technological growth in recent years which has led to significant advances in high-lift systems. For this reason many existing design methodologies have become obsolete since they are based on outdated low Reynolds number wind-tunnel data and can no longer accurately predict the aerodynamic characteristics or weight of current multi-element wings. Therefore, a new design methodology has been created that reflects current aerodynamic, weight, and cost data and provides enough flexibility to allow incorporation of new data when it becomes available.

Pepper, R. S.↗

NASA NTRS1999

NCC: A Multidisciplinary Design/Analysis Tool for Combustion Systems

Liu, Nan-Suey↗

NASA NTRS2000

A Primer In Advanced Fatigue Life Prediction Methods

Metal fatigue has plagued structural components for centuries, and it remains a critical durability issue in today's aerospace hardware. This is true despite vastly improved and advanced materials, increased mechanistic understanding, and development of accurate structural analysis and advanced fatigue life prediction tools. Each advance is quickly taken advantage of to produce safer, more reliable more cost effective, and better performing products. In other words, as the envelop is expanded, components are then designed to operate just as close to the newly expanded envelop as they were to the initial one. The problem is perennial. The economic importance of addressing structural durability issues early in the design process is emphasized. Tradeoffs with performance, cost, and legislated restrictions are pointed out. Several aspects of structural durability of advanced systems, advanced materials and advanced fatigue life prediction methods are presented. Specific items include the basic elements of durability analysis, conventional designs, barriers to be overcome for advanced systems, high-temperature life prediction for both creep-fatigue and thermomechanical fatigue, mean stress effects, multiaxial stress-strain states, and cumulative fatigue damage accumulation assessment.

Halford, Gary R.↗

NASA NTRS2002

NASA GRC Fatigue Crack Initiation Life Prediction Models

Metal fatigue has plagued structural components for centuries, and it remains a critical durability issue in today's aerospace hardware. This is true despite vastly improved and advanced materials, increased mechanistic understanding, and development of accurate structural analysis and advanced fatigue life prediction tools. Each advance is quickly taken advantage of to produce safer, more reliable, more cost effective, and better performing products. In other words, as the envelope is expanded, components are then designed to operate just as close to the newly expanded envelope as they were to the initial one. The problem is perennial. The economic importance of addressing structural durability issues early in the design process is emphasized. Tradeoffs with performance, cost, and legislated restrictions are pointed out. Several aspects of structural durability of advanced systems, advanced materials and advanced fatigue life prediction methods are presented. Specific items include the basic elements of durability analysis, conventional designs, barriers to be overcome for advanced systems, high-temperature life prediction for both creep-fatigue and thermomechanical fatigue, mean stress effects, multiaxial stress-strain states, and cumulative fatigue damage accumulation assessment.

Arya, Vinod K.↗

NASA NTRS2021

Equuleus Launch Window Analysis and Mission Design

This paper presents the trajectory design process for EQUULEUS, a 6U CubeSat developed by JAXA and the University of Tokyo that is scheduled to launch as a piggyback of NASA’s Artemis 1. After separation from the upper stage of the Space Launch System, EQUULEUS will maneuver along a low-energy transfer to an Earth–Moon quasi-rectilinear halo orbit in 1-to-4 resonance with the lunar synodic period. As a secondary payload, the trajectory of EQUULEUS needs to be compatible with the requirements of the primary mission, but also robust against disturbances and potential changes in the deployment state. Realistic initial conditions spanning two years of potential launch windows are processed and the solution structure for optimal lunar transfers is analyzed. A host of candidate solutions is presented, compatibly with the fuel and power limitations of EQUULEUS. The global understanding of the solution space is shown to be insightful for the design of robust trajectories for limited control-authority spacecraft.

Kawakatsu, Yasuhiro↗

DOE OSTI2019

Recent Regulatory Challenges Associated with Managing NORM and TENORM Waste Streams in the United States - 19609

Recent regulatory changes in several states in the United States (U.S.) have introduced new challenges to industries impacted with naturally occurring radioactive materials (NORM) and/or technologically enhanced NORM (TENORM) requiring innovative solutions. Because NORM and TENORM are specifically exempt from U.S. Nuclear Regulatory Commission (NRC) regulations, the onus falls on the 50 states to regulate their use and disposal. Over the past 10 years, regulations applying to NORM and TENORM have been drafted, passed, or updated in multiple states, including North Dakota, Pennsylvania, Illinois, and West Virginia to name a few. Solutions and lessons learned before and during the recent regulatory changes for a variety of clients, including specialty metals, mining, and oil and gas (O and G), are presented. In addition, the design and implementation of the comprehensive study of NORM/TENORM associated with conventional and unconventional O and G production activities in Pennsylvania on behalf of the Pennsylvania Department of Environmental Protection (PADEP) is presented, and the development of analytical solutions and waste processes designed to minimize the impact of the new regulations while maintaining compliance is discussed. (author)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2020

Scale-free, programmable design of morphable chain loops of kilobots and colloidal motors

Micron-scale robots require systems that can morph into arbitrary target configurations controlled by external agents such as heat, light, electricity, and chemical environment. Achieving this behavior using conventional approaches is challenging because the available materials at these scales are not programmable like their macroscopic counterparts. To overcome this challenge, we propose a design strategy to make a robotic machine that is both programmable and compatible with colloidal-scale physics. Our strategy uses motors in the form of active colloidal particles that constantly propel forward. We sequence these motors end-to-end in a closed chain forming a two-dimensional loop that folds under its mechanical constraints. We encode the target loop shape and its motion by regulating six design parameters, each scale-invariant and achievable at the colloidal scale. We demonstrate the plausibility of our design strategy using centimeter-scale robots called kilobots . We use Brownian dynamics simulation to explore the large design space beyond that possible with kilobots, and present an analytical theory to aid the design process. Multiple loops can also be fused together to achieve several complex shapes and robotic behaviors, demonstrated by folding a letter shape “M,” a dynamic gripper , and a dynamic pacman . The material-agnostic, scale-free, and programmable nature of our design enables building a variety of reconfigurable and autonomous robots at both colloidal scales and macroscales.

36 MATERIALS SCIENCE↗

NASA NTRS1987

A structural model for composite rotor blades and lifting surfaces

Composite material systems are currently candidates for aerospace structures, primarily for the design flexibiity they offer i.e., it is possible to tailor the material and manufacturing approach to the application. Two notable examples are the wing of the Grumman/USAF/DARPA X-29 and rotor blades under development by the U.S.A. Aerostructures Directorate (AVSCOM), Langley Research Center. A working definition of elastic or structural tailoring is the use of structural concept, fiber orientation, ply stacking sequence, and a blend of materials to achieve specific performance goals. In the design process, choices of materials and dimensions are made which produce specific response characteristics which permit the selected goals to be achieved. Common choices for tailoring goals are preventing instabilities or vibration resonances or enhancing damage tolerance. An essential, enabling factor in the design of tailored composite structures is structural modeling that accurately, but simply, characterizes response. The objective of this paper is to improve the single-cell beam model for composite rotor blades or lifting surfaces and to demonstrate its usefullness in applications.

Rehfield, Lawrence W.↗

NASA NTRS1991

Proximity operations considerations affecting spacecraft design

Experience from several recent spacecraft development programs, such as Space Station Freedom (SSF) and the Orbital Maneuvering Vehicle (OMV) has shown the need for factoring proximity operations considerations into the vehicle design process. Proximity operations, those orbital maneuvers and procedures which involve operation of two or more spacecraft at ranges of less than one nautical mile, are essential to the construction, servicing, and operation of complex spacecraft. Typical proximity operations considerations which drive spacecraft design may be broken into two broad categories; flight profile characteristics and concerns, and use of various spacecraft systems during proximity operations. Proximity operations flight profile concerns include the following: (1) relative approach/separation line; (2) relative orientation of the vehicles; (3) relative translational and rotational rates; (4) vehicle interaction, in the form of thruster plume impingement, mating or demating operations, or uncontrolled contact/collision; and (5) active vehicle piloting. Spacecraft systems used during proximity operations include the following: (1) sensors, such as radar, laser ranging devices, or optical ranging systems; (2) effector hardware, such as thrusters; (3) flight control software; and (4) mating hardware, needed for docking or berthing operations. A discussion of how these factors affect vehicle design follows, addressing both active and passive/cooperative vehicles.

Staas, Steven K.↗

NASA NTRS2001

Space Transportation Operations: Assessment of Methodologies and Models

The systems design process for future space transportation involves understanding multiple variables and their effect on lifecycle metrics. Variables such as technology readiness or potential environmental impact are qualitative, while variables such as reliability, operations costs or flight rates are quantitative. In deciding what new design concepts to fund, NASA needs a methodology that would assess the sum total of all relevant qualitative and quantitative lifecycle metrics resulting from each proposed concept. The objective of this research was to review the state of operations assessment methodologies and models used to evaluate proposed space transportation systems and to develop recommendations for improving them. It was found that, compared to the models available from other sources, the operations assessment methodology recently developed at Kennedy Space Center has the potential to produce a decision support tool that will serve as the industry standard. Towards that goal, a number of areas of improvement in the Kennedy Space Center's methodology are identified.

Joglekar, Prafulla↗

NASA NTRS2001

Overview of the NCC

A multi-disciplinary design/analysis tool for combustion systems is critical for optimizing the low-emission, high-performance combustor design process. Based on discussions between then NASA Lewis Research Center and the jet engine companies, an industry-government team was formed in early 1995 to develop the National Combustion Code (NCC), which is an integrated system of computer codes for the design and analysis of combustion systems. NCC has advanced features that address the need to meet designer's requirements such as "assured accuracy", "fast turnaround", and "acceptable cost". The NCC development team is comprised of Allison Engine Company (Allison), CFD Research Corporation (CFDRC), GE Aircraft Engines (GEAE), NASA Glenn Research Center (LeRC), and Pratt & Whitney (P&W). The "unstructured mesh" capability and "parallel computing" are fundamental features of NCC from its inception. The NCC system is composed of a set of "elements" which includes grid generator, main flow solver, turbulence module, turbulence and chemistry interaction module, chemistry module, spray module, radiation heat transfer module, data visualization module, and a post-processor for evaluating engine performance parameters. Each element may have contributions from several team members. Such a multi-source multi-element system needs to be integrated in a way that facilitates inter-module data communication, flexibility in module selection, and ease of integration. The development of the NCC beta version was essentially completed in June 1998. Technical details of the NCC elements are given in the Reference List. Elements such as the baseline flow solver, turbulence module, and the chemistry module, have been extensively validated; and their parallel performance on large-scale parallel systems has been evaluated and optimized. However the scalar PDF module and the Spray module, as well as their coupling with the baseline flow solver, were developed in a small-scale distributed computing environment. As a result, the validation of the NCC beta version as a whole was quite limited. Current effort has been focused on the validation of the integrated code and the evaluation/optimization of its overall performance on large-scale parallel systems.

Liu, Nan-Suey↗

NASA NTRS2002

Space Transportation Operations: Assessment of Methodologies and Models

Joglekar, Prafulla↗

NASA NTRS2010

Maximizing Launch Vehicle and Payload Design Via Early Communications

The United States? current fleet of launch vehicles is largely derived from decades-old designs originally made for payloads that no longer exist. They were built primarily for national security or human exploration missions. Today that fleet can be divided roughly into small-, medium-, and large-payload classes based on mass and volume capability. But no vehicle in the U.S. fleet is designed to accommodate modern payloads. It is usually the payloads that must accommodate the capabilities of the launch vehicles. This is perhaps most true of science payloads. It was this paradigm that the organizers of two weekend workshops in 2008 at NASA's Ames Research Center sought to alter. The workshops brought together designers of NASA's Ares V cargo launch vehicle (CLV) with scientists and payload designers in the astronomy and planetary sciences communities. Ares V was still in a pre-concept development phase as part of NASA?s Constellation Program for exploration beyond low Earth orbit (LEO). The space science community was early in a Decadal Survey that would determine future priorities for research areas, observations, and notional missions to make those observations. The primary purpose of the meetings in April and August of 2008, including the novel format, was to bring vehicle designers together with space scientists to discuss the feasibility of using a heavy lift capability to launch large observatories and explore the Solar System. A key question put to the science community was whether this heavy lift capability enabled or enhanced breakthrough science. The meetings also raised the question of whether some trade-off between mass/volume and technical complexity existed that could reduce technical and programmatic risk. By engaging the scientific community early in the vehicle design process, vehicle engineers sought to better understand potential limitations and requirements that could be added to the Ares V from the mission planning community. From the vehicle standpoint, while the human exploration mission could not be compromised to accommodate other payloads, the design might otherwise be tailored to not exclude other payload requirements. This paper summarizes the findings of the workshops and discusses the benefits of bringing together the vehicle design and science communities early in their concept phases

Morris, Bruce↗

NASA NTRS2014

Lunar Cube Transfer Trajectory Options

Contingent upon the modification of an initial condition of the injected or deployed orbit. Additionally, these designs can be restricted by the selection of the Cubesat subsystem design such as propulsion or communication. Nonetheless, many trajectory options can be designed with have a wide range of transfer durations, fuel requirements, and final destinations. Our investigation of potential trajectories highlights several design options including deployment into low Earth orbit (LEO), geostationary transfer orbits (GTO), and higher energy direct lunar transfer orbits. In addition to direct transfer options from these initial orbits, we also investigate the use of longer duration Earth-Moon dynamical systems. For missions with an intended lunar orbit, much of the design process is spent optimizing a ballistic capture while other science locations such as Sun-Earth libration or heliocentric orbits may simply require a reduced Delta-V imparted at a convenient location along the trajectory. In this article we examine several design options that meet the above limited deployment and subsystem drivers. We study ways that both impulsive and low-thrust Solar Electric Propulsion (SEP) engines can be used to place the Cubesat first into a highly eccentric Earth orbit, enter the Moon's Sphere of Influence, and finally achieve a highly eccentric lunar orbit. We show that such low-thrust transfers are feasible with a realistic micro-thruster model, assuming that the Cubesat can generate sufficient power for the SEP. Two examples are shown here: (1) A Cubestat injected by Exploration Mission 1 (EM-1) then employing low thrust; and (2) a CubSat deployed in a GTO, then employing impulsive maneuvers. For the EM-1 injected initial design, we increase the EM-1 targeted lunar flyby distance to reduce the energy of the lunar flyby to match that of a typical lMoon system heteroclinic manifold. Figure 1 presents an option that encompasses the similar dynamics as that of the ARTEMIS mission design. Low-thrust maneuvers are used along the manifold trajectory to raise perigee to that of a lunar orbit, adjust the timing with respect to the Moon, rotate the line of apsides, and target a ballistic lunar encounter. In this design a second flyby decreases the orbital energy with respect to the Moon, so that C3 -0.1 km2s2. Another design, shown in Figure 2 emanates from a GTO then uses impulsive maneuvers to phase onto a local Earth-Moon manifold, which then transfers the CubeSat to a lunar encounter.

Dynamical System↗

DOE OSTI2023

Phase-based design of CO 2 capture, transport, and storage infrastructure via SimCCS 3.0

The design of optimal infrastructure is essential for the deployment of commercial and large-scale carbon capture and storage (CCS) technology. During the design process, it is important to consider CO 2 capture and storage locations and CO 2 transportation pipelines to minimize the total project cost. SimCCS, first introduced in 2009, is an integrated open-source tool to optimize CCS infrastructure. The core CCS infrastructure design problem in SimCCS is structured as a mixed-integer linear programming problem by selecting the optimal pipeline routes, searching CO 2 source capture and storage locations, and determining the corresponding CO 2 amounts to meet desired capture targets. Multiple important and practical features have been developed to the latest version of SimCCS, SimCCS 3.0 . One of these features is phase-based modeling which enables users to dynamically design the CCS infrastructure. We demonstrate the phased-based modeling capability using two CCS infrastructure optimization case studies. The results from these case studies reveal that the phase-based modeling capability in SimCCS is particularly useful to optimize the dynamic deployment of CCS projects.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2018

Hardware Evaluation: Abstract Machine Models and Proxy Architectures for Exascale Computing

The strategic and economic impacts of high performance computing (HPC) systems, over the last several decades, have enabled dramatic improvements in manufacturing, design, development, and research, across almost every sector of the U.S. economy, including genetic analysis for agriculture and medicine, oil exploration, electronics, aircraft, and automotive design, and of course national defense technologies. HPC has repeatedly compounded reductions in time-to-solution and time-to-market in each of these areas. In recognition of these strategic and economic impacts, the Department of Energy (DOE) created the Exascale Computing Project (ECP) as a broad-based technology project focusing on simultaneously co-evolving high-performance computing architecture, system software, and application software. While many details of the exascale architectures are undefined, communicating the form and direction of this co-evolution of advances, in each of these three components, across the project, presents a need for a common language through which these advances can be shared. In this document we present a series of abstract representations designed to allow application developers to focus on the aspects of the machine that are important or relevant to performance and code structure. These abstract machine models (AMMs) describe the proposed architectures at the component and system level and are intended as communication aids between application developers and hardware architects during the co-design process. In addition to providing a common language for communication, the constraints of protecting the intellectual property of ECP’s vendor partners requires that the architectural advances be presented in an abstract sense, rather than exposing the specifics of an individual vendor’s designs, while still providing enough detail such that application developers will be able to reason about the performance trade-offs in the design space of their applications.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2012

High-Surface-Area Inorganic Membrane for Process Water Removal: Application to Ethanol Fuel Production

This report summarizes process research results about concept development of thin flat sheet water-selective molecular sieve membrane – a breakthrough membrane product technology for separation of water from ethanol-enriched process streams. The studies include 1) membrane separation performance testing with real-world feeds sampled from Pacific Ethanol Inc’s ethanol plant at Boardman, Oregon and 2) process design and simulation of membrane separation implementation into a corn ethanol plant. The separation tests were conducted on a laboratory-bench testing apparatus in a batch operation mode with small membrane samples (about 1-inch diameter) but under practical conditions, while the process simulation was performed using ASPEN and USDA models. A two-stage membrane separation system is proposed to conduct ethanol enrichment and purification by replacing respective distillation and adsorption process. More than 90% energy saving can be obtained using the membrane separation. It is estimated that the membrane unit for a 40 million gal/year of ethanol plant can be fairly compact - about the sizes of a plate heat exchanger due to high flux of the new membrane. The cost and lifetime of this new membrane product are critical factors to lower the capital cost. This membrane technology is promising for upgrading of existing corn ethanol plants and for building of new cellulosic ethanol plants in the future as well. The results obtained in this work warrant further development of membrane module prototypes and demonstration of their long-term operation stability with slip streams at ethanol plants, which is necessary to move the technology toward commercialization.

09 BIOMASS FUELS↗

DOE OSTI2024

Cost-optimal selection of pH control for mineral scaling prevention in high recovery reverse osmosis desalination

Conference proceedings for Foundations of Computer Aided Process Design (FOCAPD) 2024 that details a cost optimization model for pH control to prevent mineral scaling in high recovery reverse osmosis. This work applies a framework for incorporating detailed water chemistry predictions such as precipitation, pH change, and mineral scaling tendencies with process-scale optimization. It demonstrates that the acid choice for pH control can have a significant impact on pretreatment costs.

Amusat, Oluwamayowa↗