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Results for “Module Reliability”

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

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At least 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

In Situ Loading and Delivery of Short Single- and Double-Stranded DNA by Supramolecular Organic Frameworks

Short DNA represents an important class of biomacromolecules that are widely applied in gene therapy, editing, and modulation. However, the development of simple and reliable methods for their intracellular delivery remains a challenge. Herein, we describe that seven water-soluble, homogeneous supramolecular organic frameworks (SOFs) with a well-defined pore size and high stability in water that can accomplish in situ inclusion of single-stranded (ss) and double-stranded (ds) DNA (21, 23, and 58 nt) and effective intracellular delivery (including two noncancerous and six cancerous cell lines). Fluorescence quenching experiments for single and double end-labeled ss- and ds-DNA support that the DNA sequences can be completely enveloped by the SOFs. Confocal laser scanning microscopy and flow cytometry reveal that five of the SOFs exhibit excellent delivery efficiencies that, in most of the studied cases, outperform the commercial standard Lipo2000, even at low SOF–nucleic acid ratios. In addition to high delivery efficiencies, the water-soluble, self-assembled SOF carriers have a variety of advantages, including convenient preparation, high stability, and in situ DNA inclusion, which are all critical for practical applications in nucleic acid delivery.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1979

Contamination control in hybrid microcircuit modules

The influence of chemical and particulate contamination upon the reliability and service life of hybrid microelectronic systems is documented. Several coating systems used include the parylene and Dow Corning silicone (DC90-711). These passivating coatings have potential for decreasing the degradation caused by particulate contaminants in hybrid systems as well as the possible deleterious effect of trapping chemical contaminants which have long term degrading influences upon the performance of the system. The reliability of a representative hybrid microcircuit is enhanced by the coating process.

Kinser, D. L.↗
NASA NTRS1986

Orbit Transfer Rocket Engine Technology Program: Advanced engine study, task D.1/D.3

Concepts for space maintainability of OTV engines were examined. An engine design was developed which was driven by space maintenance requirements and by a failure mode and effects (FME) analysis. Modularity within the engine was shown to offer cost benefits and improved space maintenance capabilities. Space operable disconnects were conceptualized for both engine change-out and for module replacement. Through FME mitigation the modules were conceptualized to contain the least reliable and most often replaced engine components. A preliminary space maintenance plan was developed around a controls and condition monitoring system using advanced sensors, controls, and condition monitoring concepts. A complete engine layout was prepared satisfying current vehicle requirements and utilizing projected component advanced technologies. A technology plan for developing the required technology was assembled.

Martinez, A.↗
NASA NTRS1987

Optimal reconfiguration strategy for a degradable multimodule computing system

The present quantitative approach to the problem of reconfiguring a degradable multimode system assigns some modules to computation and arranges others for reliability. By using expected total reward as the optimal criterion, there emerges an active reconfiguration strategy based not only on the occurrence of failure but the progression of the given mission. This reconfiguration strategy requires specification of the times at which the system should undergo reconfiguration, and the configurations to which the system should change. The optimal reconfiguration problem is converted to integer nonlinear knapsack and fractional programming problems.

Lee, Yann-Hang↗
NASA NTRS2007

Foundation for Heavy Lift - Early Developments in the Ares V Launch Vehicle

The Ares V Cargo Launch Vehicle (CaLV) is NASA's primary vessel for safe, reliable delivery of the Lunar Surface Access Module (LSAM) and other resources into Earth orbit, as articulated in the U.S. Vision for Space Exploration. The Ares V launch concept is shown. The foundation for this heavy-lift companion to the Ares I Crew Launch Vehicle (CLV) is taking shape within NASA and with its government and industry partners. This paper will address accomplishments in the Ares V Launch Vehicle during 2006 and 2007 and offer a preview of future activities.

McArthur, J. Craig↗
NASA NTRS2007

Foundation for Heavy Lift: Early Developments in the Ares V Cargo Launch Vehicle

The Ares V Cargo Launch Vehicle (CaLV) is NASA's primary vessel for safe, reliable delivery of the Lunar Surface Access Module (LSAM) and other resources into Earth orbit, as articulated in the U.S. Vision for Space Exploration.' The Ares V launch concept is shown. The foundation for this heavy-lift companion to the Ares I Crew Launch Vehicle (CLV) is taking shape within NASA and with its government and industry partners. This paper will address accomplishments in the Ares V Launch Vehicle during 2006 and 2007 and offer a preview of future activities.

Sumrall, John P.↗
NASA NTRS2018

Estimating Software Reliability for Space Launch Vehicles in Probabilistic Risk Assessment (PRA)

It is acutely recognized in the Probabilistic Risk assessment (PRA) field that software plays a defining role in overall system reliability for all modern systems across a wide variety of industries. Regardless if the software is embedded firmware for working components or elements, part of a Human-Machine-Interface, or automated command and control logic, the success of the software to fulfill its function under nominal and off-nominal environments will be a dominant contributor to system reliability. It is also recognized that software reliability prediction and estimation is one of the more challenging and questionable aspects of any PRA or system analyses due to the nature of software and its integration with physics based systems. Irrespective of this dichotomy, any incorporation of software reliability methods requires that the contributions are accountable, quantitative, and tractable. This paper provides a brief overview of software reliability methods, establishes some minimum requirements that the methods should incorporate for completeness, and provides a logic structure for applying software reliability. Model resolution will be discussed that supports current testing plans and trade studies. We will provide initial recommendations for use in the NASA PRA and present a future dynamic option for software and PRA. Space Launch Vehicle Software is recognized to be reliable in static conditions, yet relatively vulnerable to a set of failure modes in changing environments/flight phases. Two quantitative methods were chosen to incorporate software reliability into a Space Launch Vehicle PRA accounting for phase adjustments. One method predicts latent software failure using statistical methods, and the second provides estimates of coding errors and software operating system failures based on test and historical data, respectively. Software uncertainty will also be discussed. We determined that recommendations for PRA software reliability should be modeled at the software module level where multiple software components compose a module and combinations of the software architecture can lead to a functional failure.

Novack, Steven↗
NASA NTRS2018

Estimating Software Reliability for Space Launch Vehicles in Probabilistic Risk Assessment (PRA)

It is acutely recognized in the Probabilistic Risk Assessment (PRA) field that software plays a defining role in overall system reliability for all modern systems across a wide variety of industries. Regardless of whether the software is embedded firmware for working components or elements, part of a Human-Machine-Interface, or automated command and control logic, the success of the software to fulfill its function under nominal and off-nominal environments will be a dominant contributor to system reliability. It is also recognized that software reliability prediction and estimation is one of the more challenging and questionable aspects of any PRA or system analyses due to the nature of software and its integration with physics based systems. Irrespective of this dichotomy, any incorporation of software reliability methods requires that the contributions are accountable, quantitative, and tractable. This paper provides a brief overview of software reliability methods, establishes some minimum requirements that the methods should incorporate for completeness, and provides a logic structure for applying software reliability. Model resolution will be discussed that supports current testing plans and trade studies. We will provide initial recommendations for use in the National Aeronautics and Space Administration (NASA) PRA and present a future dynamic option for software and PRA. Space Launch Vehicle software is recognized to be reliable in static conditions, yet relatively vulnerable to a set of failure modes in changing environments/flight phases. Two quantitative methods were chosen to incorporate software reliability into a Space Launch Vehicle PRA accounting for phase adjustments. One method predicts latent software failure using statistical methods, and the second provides estimates of coding errors and software operating system failures based on test and historical data. Software uncertainty will also be discussed. It is determined that recommendations for PRA software reliability should be modeled at the software module level where multiple software components compose a module and combinations of the software architecture can lead to a functional failure.

Steven D. Novack↗
NASA NTRSDate not supplied

Developing the CRTM Active Sensor Module

Active sensors provide vertically resolved atmospheric and cloud information, however the assimilation of such observations into NWP models has been limited for several reasons including lack of reliable forward model. We present the development of CRTM active sensor module including its adjoint and tangent linear by taking advantage of current CRTM modules for calculating atmospheric transmittance and cloud absorption and scattering. Current CRTM cloud coefficients lack cloud backscattering information, thus we have implemented a new cloud scattering database generated using the discrete dipole technique that include backscattering coefficients. The radar simulator is currently being tested within the JEDI/GEOS data assimilation framework to facilitate the assimilation of radar measurements such as CloudSat CPR and GPM DPR into the NASA GEOS model.

CRTM↗
DOE OSTI2021

Evaluating ZEBRA Battery Module under the Peak-Shaving Duty Cycles

With the recent rapid increase in demand for reliable, long-cycle life, and safe battery technologies for large-scale energy-storage applications, a battery module based on ZEBRA battery chemistry is extensively evaluated for its application in peak shaving duty cycles. First, this module is tested with a full capacity cycle consisting of a charging process (factory default) and a discharging process with a current of 40 A. The battery energy efficiency (discharge vs. charge) is about 90%, and the overall energy efficiency is 80.9%, which includes the auxiliary power used to run the battery management system electronics and self-heating to maintain the module operating temperature (265 °C). Generally, because of the increased self-heating during the holding times that exist for the peak shaving duty cycles, the overall module efficiency decreases slightly for the peak-shaving duty cycles (70.7–71.8%) compared to the full-capacity duty cycle. With a 6 h, peak-shaving duty cycle, the overall energy efficiency increases from 71.8% for 7.5 kWh energy utilization to 74.1% for 8.5 kWh. We conducted long-term cycling tests of the module at a 6 h, peak-shaving duty cycle with 7.5 kWh energy utilization, and the module exhibited a capacity degradation rate of 0.0046%/cycle over 150 cycles (>150 days).

25 ENERGY STORAGE↗
DOE OSTI2015

Moving Toward Quantifying Reliability - The Next Step in a Rapidly Maturing PV Industry: Preprint

Some may say that PV modules are moving toward being a simple commodity, but most major PV customers ask: 'How can I minimize chances of a module recall?' Or, 'How can I quantify the added value of a 'premium' module?' Or, 'How can I assess the value of an old PV system that I'm thinking of purchasing?' These are all questions that PVQAT (the International PV Quality Assurance Task Force) and partner organizations are working to answer. Defining standard methods for ensuring minimal acceptable quality of PV modules, differentiating modules that provide added value in the toughest of environments, and creating a process (e.g. through IECRE [1]) that can follow a PV system from design through installation and operation are tough tasks, but having standard approaches for these will increase confidence, reduce costs, and be a critical foundation of a mature PV industry. This paper summarizes current needs for new tests, some challenges for defining those tests, and some of the key efforts toward development of international standards, emphasizing that meaningful quantification of reliability (as in defining a service life prediction) must be done in the context of a specific product with design parameters defined through a quality management system.

14 SOLAR ENERGY↗
DOE OSTI2012

Development of an AC Module System: Final Technical Report

The GreenRay Inc. program focused on simplifying solar electricity and making it affordable and accessible to the mainstream population. This was accomplished by integrating a solar module, micro-inverter, mounting and monitoring into a reliable, 'plug and play' AC system for residential rooftops, offering the following advantages: (1) Reduced Cost: Reduction in installation labor with fewer components, faster mounting, faster wiring. (2) Maximized Energy Production: Each AC Module operates at its maximum, reducing overall losses from shading, mismatch, or module downtime. (3) Increased Safety. Electrical and fire safety experts agree that AC Modules have significant benefits, with no energized wiring or live connections during installation, maintenance or emergency conditions. (4) Simplified PV for a Broader Group of Installers. Dramatic simplification of design and installation of a solar power system, enabling faster and more efficient delivery of the product into the market through well-established, mainstream channels. This makes solar more accessible to the public. (5) Broadened the Rooftop Market: AC Modules enable solar for many homes that have shading, split roofs, or obstructions. In addition, due to the smaller building block size of 200W vs. 1000W, homeowners with budget limitations can start small and add to their systems over time. Through this DOE program GreenRay developed the all-in-one AC Module system with an integrated PV Module and microinverter, custom residential mounting and performance monitoring. Development efforts took the product from its initial concept, through prototypes, to a commercial product sold and deployed in the residential market. This pilot deployment has demonstrated the technical effectiveness of the AC Module system in meeting the needs and solving the problems of the residential market. While more expensive than the traditional central inverter systems at the pilot scale, the economics of AC Modules become more and more favorable as the product matures and is made in high volumes. GreenRay's early customers have been highly enthusiastic about the AC Module system benefits.

14 SOLAR ENERGY↗
DOE OSTI2022

Worldwide Physics-Based Lifetime Prediction of c-Si Modules Due to Solder-Bond Failure

Lifetime prediction of the fielded c-Si solar modules due to location-specific weather conditions has been an important topic of photovoltaic research and the economic viability of solar energy. Data analytic techniques such as the performance ratio method, Statistical clear sky model, and Suns-Vmp methods quantify the degradation from measured data of a solar farm, however, the nonlinear time-dependence and correlated degradations make it difficult to use the empirical degradation rates for ultimate lifetime projection. In this article, we propose a complementary physics-based model to predict the solder bond failure caused by mechanical stress associated with the variations of the temperature. Integrating the worldwide weather information from NASA/NSRDB databases, the model predicts the location-specific output-power degradation and the lifetime of a module due to solder bond failure. The model parameters are calibrated against qualification tests involving thermal cycling of specific batches of modules from a specific technology/manufacturer. The results may be summarized as: 1) Modules installed at higher latitudes show a longer lifetime due to reduced damage accumulation. 2) The reduction of temperature fluctuation close to large bodies of water, such as seashores, increases solder bond lifetime significantly. 3) Relatively speaking, modules installed close to the Tropic of Cancer/Capricorn (23.5 degrees North/South) suffer from a higher solder bond damage and have a shorter lifetime, suggesting a conservative design. This model should serve as a building block of a comprehensive reliability framework that can predict the lifetime of a module that experiences simultaneous and correlated degradation mechanisms involving yellowing, corrosion, and potential-induced degradation.

14 SOLAR ENERGY↗
DOE OSTI2018

Evaluating and predicting molecular mechanisms of adhesive degradation during field and accelerated aging of photovoltaic modules

Extending photovoltaic (PV) module lifetimes beyond 30 years is a goal of significant priority. A challenge that must first be addressed, however, is the development of a predictive reliability model that captures the synergy of terrestrial stressors on module degradation, particularly at encapsulant interfaces. Using a metrology designed specifically for PV modules, a comprehensive study of the widely used ethylene vinyl acetate encapsulant was performed in which encapsulant adhesion was evaluated as a function of environmental stressors (UV exposure, temperature, and humidity) for modules aged both under accelerated lab and internationally located field conditions for months to nearly 3 decades. Mechanical and chemical characterization methods are combined with fundamental polymer reaction engineering to unravel the degradation processes active at the molecular scale that lead to encapsulant delamination. An analytical and modular model framework is put forward enabling the prediction of long-term PV module durability, starting from fundamental principles at the molecular level and explicitly accounting for bond rupture events in the bulk encapsulant and at the encapsulant interfaces. Successful parameter tuning to adhesion data indicates a dominant occurrence of deacetylation, β-scission, and hydrolytic depolymerization, respectively. The model contributes to the longstanding challenge of predicting module lifetimes in any geographic location while minimizing time-consuming and costly aging studies.

14 SOLAR ENERGY↗
DOE OSTI2026

Advanced Power Electronics and Electric Machines

NLR's advanced power electronics and electric machines (APEEM) research group develops world-class experimental and modeling capabilities to design and evaluate efficient and reliable power electronics and electric machines, as well as innovative thermal management systems to maximize their performance. They also design, fabricate, and characterize advanced power electronics packaging and are developing state-of-health monitoring techniques.

25 ENERGY STORAGE↗
DOE OSTI2014

Passive Two-Phase Cooling of Automotive Power Electronics: Preprint

Experiments were conducted to evaluate the use of a passive two-phase cooling strategy as a means of cooling automotive power electronics. The proposed cooling approach utilizes an indirect cooling configuration to alleviate some reliability concerns and to allow the use of conventional power modules. An inverter-scale proof-of-concept cooling system was fabricated, and tests were conducted using the refrigerants hydrofluoroolefin HFO-1234yf and hydrofluorocarbon HFC-245fa. Results demonstrated that the system can dissipate at least 3.5 kW of heat with 250 cm3 of HFC-245fa. An advanced evaporator design that incorporates features to improve performance and reduce size was conceived. Simulation results indicate its thermal resistance can be 37% to 48% lower than automotive dual side cooled power modules. Tests were also conducted to measure the thermal performance of two air-cooled condensers--plain and rifled finned tube designs. The results combined with some analysis were then used to estimate the required condenser size per operating conditions and maximum allowable system (i.e., vapor and liquid) temperatures.

30 DIRECT ENERGY CONVERSION↗