Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Integrated Applications”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,081 records · Page 60
All sourcesNASA NTRSDOE OSTI
NASA NTRS2010

Ka-Band SiGe Receiver Front-End MMIC for Transponder Applications

A fully integrated, front-end Ka-band monolithic microwave integrated circuit (MMIC) was developed that houses an LNA (low noise amplifier) stage, a down-conversion stage, and output buffer amplifiers. The MMIC design employs a two-step quadrature down-conversion architecture, illustrated in the figure, which results in improved quality of the down-converted IF quadrature signals. This is due to the improved sensitivity of this architecture to amplitude and phase mismatches in the quadrature down-conversion process. Current sharing results in reduced power consumption, while 3D-coupled inductors reduce the chip area. Improved noise figure is expected over previous SiGe-based, frontend designs

Venkatesan, Jaikrishna↗
NASA NTRS1989

The tapered slot antenna - A new integrated element for millimeter-wave applications

Tapered slot antennas (TSAs) with a number of potential applications as single elements and focal-plane arrays are discussed. TSAs are fabricated with photolithographic techniques and integrated in either hybrid or MMIC circuits with receiver or transmitter components. They offer considerably narrower beams than other integrated antenna elements and have high aperture efficiency and packing density as array elements. Both the circuit and radiation properties of TSAs are reviewed. Topics covered include: antenna beamwidth, directivity, and gain of single-element TSAs; their beam shape and the effect of different taper shapes; and the input impedance and the effects of using thick dielectrics. These characteristics are also given for TSA arrays, as are the circuit properties of the array elements. Different array structures and their applications are also described.

Yngvesson, K. Sigfrid↗
DOE OSTI2020

Hierarchical and scalable integration of nanostructures for energy and environmental applications: a review of processing, devices, and economic analyses

Hierarchical nanostructure, an engineered nanostructure with a higher assembly-level of constituents by low dimensional nano-building blocks, has received extensive attentions in the latest advancements in nanomaterial science and nanotechnology development. The ordered hierarchical nanostructures could offer merits such as more active sites, synergistic properties owing to their geometric complexity and building blocks variation, as well as the resultant multi-functional capabilities. In this review, we specifically focus on the integration approaches that may be feasible for large-scale production and manufacturing of engineered nanomaterials for various industrial applications, and the design criteria of hierarchical nanostructures targeted at various sustainable energy and environmental applications. In addition to chemical synthesis and integration methods, the development and application of hierarchical nanostructures are surveyed in energy conversion, generation, storage, utilization, and sensing devices. Meanwhile, a much-needed survey is also touched upon the techno-economic analyses of engineered nanomaterials, proposing the need of establishing various standard protocols on various factors and parameters that could be envisaged as a guide toward the viable transition to the practices in the future nano-industries.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2013

Architectures and Control of Submodule Integrated DC-DC Converters for Photovoltaic Applications

This paper describes photovoltaic (PV) module architectures with parallel-connected submodule-integrated dc-dc converters (subMICs) that improve efficiency of energy capture in the presence of partial shading or other mismatch conditions. The subMICs are bidirectional isolated dc-dc converters capable of injecting or subtracting currents to balance the module substring voltages. When no mismatches are present, the subMICs are simply shut down, resulting in zero insertion losses. It is shown that the objective of minimum subMIC power processing can be solved as a linear programming problem. A simple close-to-optimal distributed control approach is presented that allows autonomous subMIC control without the need for a central controller or any communication among the subMICs. Furthermore, the proposed control approach is well suited for an isolated-port architecture, which yields additional practical advantages including reduced subMIC power and voltage ratings. The architectures and the control approach are validated by simulations and experimental results using three bidirectional flyback subMICs attached to a standard 180-W, 72-cell PV module, yielding greater than 98% module-level power processing efficiency for a mismatch less than 25%.

Olalla, C↗
NASA NTRS1974

The nu sub 9 fundamental of ethane - Integrated intensity and band absorption measurements with application to the atmospheres of the major planets

Measurements of the absolute intensity and integrated band absorption have been performed for the nu sub 9 fundamental band of ethane. The intensity is found to be about 34 per sq cm per atm at STP, and this is significantly higher than previous estimates. It is shown that a Gaussian profile provides an empirical representation of the apparent spectral absorption coefficient. Employing this empirical profile, a simple expression is derived for the integrated band absorption, which is in excellent agreement with experimental values. The band model is then employed to investigate the possible role of ethane as a source of thermal infrared opacity within the atmospheres of Jupiter and Saturn, and to interpret qualitatively observed brightness temperatures for Saturn.

Varanasi, P.↗
NASA NTRS1987

Monolithic Microwave Integrated Circuit (MMIC) technology for space communications applications

Future communications satellites are likely to use gallium arsenide (GaAs) monolithic microwave integrated-circuit (MMIC) technology in most, if not all, communications payload subsystems. Multiple-scanning-beam antenna systems are expected to use GaAs MMICs to increase functional capability, to reduce volume, weight, and cost, and to greatly improve system reliability. RF and IF matrix switch technology based on GaAs MMICs is also being developed for these reasons. MMIC technology, including gigabit-rate GaAs digital integrated circuits, offers substantial advantages in power consumption and weight over silicon technologies for high-throughput, on-board baseband processor systems. For the more distant future pseudomorphic indium gallium arsenide (InGaAs) and other advanced III-V materials offer the possibility of MMIC subsystems well up into the millimeter wavelength region. All of these technology elements are in NASA's MMIC program. Their status is reviewed.

Connolly, Denis J.↗
NASA NTRS1987

Monolithic Microwave Integrated Circuit (MMIC) technology for space communications applications

Future communications satellites are likely to use gallium arsenide (GaAs) monolithic microwave integrated-circuit (MMIC) technology in most, if not all, communications payload subsystems. Multiple-scanning-beam antenna systems are expected to use GaAs MMIC's to increase functional capability, to reduce volume, weight, and cost, and to greatly improve system reliability. RF and IF matrix switch technology based on GaAs MMIC's is also being developed for these reasons. MMIC technology, including gigabit-rate GaAs digital integrated circuits, offers substantial advantages in power consumption and weight over silicon technologies for high-throughput, on-board baseband processor systems. For the more distant future pseudomorphic indium gallium arsenide (InGaAs) and other advanced III-V materials offer the possibility of MMIC subsystems well up into the millimeter wavelength region. All of these technology elements are in NASA's MMIC program. Their status is reviewed.

Connolly, Denis J.↗
DOE OSTI2014

SU-E-T-27: A Tool for Routine Quality Assurance of Radiotherapy Dose Calculation Software

Purpose: Dose calculation software is thoroughly evaluated when it is commissioned; however, evaluation of periodic software updates is typically limited in scope due to staffing constraints and the need to quickly return the treatment planning system to clinical service. We developed a tool for quickly and comprehensively testing and documenting dose calculation software against measured data. Methods: A tool was developed using MatLab (The MathWorks, Natick, MA) for evaluation of dose calculation algorithms against measured data. Inputs to the tool are measured data, reference DICOM RT PLAN files describing the measurements, and dose calculations in DICOM format. The tool consists of a collection of extensible modules that can perform analysis of point dose, depth dose curves, and profiles using dose difference, distance-to-agreement, and the gamma-index. Each module generates a report subsection that is incorporated into a master template, which is converted to final form in portable document format (PDF). Results: After each change to the treatment planning system, a report can be generated in approximately 90 minutes. The tool has been in use for more than 5 years, spanning 5 versions of the eMC and 4 versions of the AAA. We have detected changes to the algorithms that affected clinical practice once during this period. Conclusion: Our tool provides an efficient method for quality assurance of dose calculation software, providing a complete set of tests for an update. Future work includes the addition of plan level tests, allowing incorporation of, for example, the TG-119 test suite for IMRT, and integration with the treatment planning system via an application programming interface. Integration with the planning system will permit fully-automated testing and reporting at scheduled intervals.

07 ISOTOPE AND RADIATION SOURCES↗
NASA NTRS1993

Application of controller partitioning optimization procedure to integrated flight/propulsion control design for a STOVL aircraft

A parameter optimization framework has earlier been developed to solve the problem of partitioning a centralized controller into a decentralized, hierarchical structure suitable for integrated flight/propulsion control implementation. This paper presents results from the application of the controller partitioning optimization procedure to IFPC design for a Short Take-Off and Vertical Landing (STOVL) aircraft in transition flight. The controller partitioning problem and the parameter optimization algorithm are briefly described. Insight is provided into choosing various 'user' selected parameters in the optimization cost function such that the resulting optimized subcontrollers will meet the characteristics of the centralized controller that are crucial to achieving the desired closed-loop performance and robustness, while maintaining the desired subcontroller structure constraints that are crucial for IFPC implementation. The optimization procedure is shown to improve upon the initial partitioned subcontrollers and lead to performance comparable to that achieved with the centralized controller. This application also provides insight into the issues that should be addressed at the centralized control design level in order to obtain implementable partitioned subcontrollers.

Garg, Sanjay↗
NASA NTRS1993

Application of controller partitioning optimization procedure to integrated flight/propulsion control design for a STOVL aircraft

A parameter optimization framework has earlier been developed to solve the problem of partitioning a centralized controller into a decentralized, hierarchical structure suitable for integrated flight/propulsion control implementation. This paper presents results from the application of the controller partitioning optimization procedure to IFPC design for a Short Take-Off and Vertical Landing (STOVL) aircraft in transition flight. The controller partitioning problem and the parameter optimization algorithm are briefly described. Insight is provided into choosing various 'user' selected parameters in the optimization cost function such that the resulting optimized subcontrollers will meet the characteristics of the centralized controller that are crucial to achieving the desired closed-loop performance and robustness, while maintaining the desired subcontroller structure constraints that are crucial for IFPC implementation. The optimization procedure is shown to improve upon the initial partitioned subcontrollers and lead to performance comparable to that achieved with the centralized controller. This application also provides insight into the issues that should be addressed at the centralized control design level in order to obtain implementable partitioned subcontrollers.

Garg, Sanjay↗
DOE OSTI2019

High-Q microsphere integrated with a tapered fiber suitable for biosensing applications

We propose a novel whispering gallery mode (WGM) microsphere resonator integrated with a tapered optical fiber. In the proposed structure, the surface of the silica microsphere is coated with a thin layer of Hafnia (Hafnium dioxide). The results from analytical and numerical simulations indicated that the WGMs can be efficiently excited with quality factors, Q, up to 1.9 × 10{sup 5} in a silica-coated microsphere with a diameter of 24.08 μm, coupled to a tapered silica fiber with 1 μm core radius. The sensitivity, S, and figure of merit, FOM, of the proposed structure were 69 nm/R.I.U (nanometers per refractive index unit) and 1.3 × 10{sup 7}, respectively. Integration of microspheres and coupling system with High-Q and Ultra-High-S can be used for various applications such as detection and biosensing.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1975

A new methodology to integrate planetary quarantine requirements into mission planning, with application to a Jupiter orbiter

A new methodology is proposed for integrating planetary quarantine objectives into space exploration planning. This methodology is designed to remedy the major weaknesses inherent in the current formulation of planetary quarantine requirements. Application of the methodology is illustrated by a tutorial analysis of a proposed Jupiter Orbiter mission. The proposed methodology reformulates planetary quarantine planning as a sequential decision problem. Rather than concentrating on a nominal plan, all decision alternatives and possible consequences are laid out in a decision tree. Probabilities and values are associated with the outcomes, including the outcome of contamination. The process of allocating probabilities, which could not be made perfectly unambiguous and systematic, is replaced by decomposition and optimization techniques based on principles of dynamic programming. Thus, the new methodology provides logical integration of all available information and allows selection of the best strategy consistent with quarantine and other space exploration goals.

Howard, R. A.↗
DOE OSTI2018

Integrated Semigroups and C-Semigroups and their Applications

In this survey, some interesting generalizations of the theory of C{sub 0}-semigroups and their applications are presented. The survey is divided into three parts: “Integrated semigroups,” “C-semigroups,” and “Applications.” Different approaches to the theory are discussed. The content presented is taken from articles of the last 20 years and also contains some results of the authors. Various applications are presented; most of them concern ill-posed Cauchy problems.

97 MATHEMATICS AND COMPUTING↗