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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 613 records · Page 34

All sources NASA NTRS DOE OSTI

DOE OSTI2018

Developmental dynamics of stem starch accumulation in Sorghum bicolor

Sweet sorghums were identified that accumulate up to ~9% of their total stem dry weight as starch. Starch accumulated preferentially in stem pith parenchyma in close proximity to vascular bundles. Stem starch accumulated slowly between floral initiation and anthesis and more rapidly between anthesis and 43 days post-anthesis before declining in parallel with tiller outgrowth. Genes involved in stem starch metabolism were identified through phylogenetic approaches and RNA-seq analysis of Della stem gene expression during the starch accumulation phase of development. Genes differentially expressed in stems were identified that are involved in starch biosynthesis (i.e., AGPase SS/LS, starch synthases, starch-branching enzymes), degradation (i.e., glucan-water dikinase, β-amylase, disproportionating enzyme, alpha-glucan phosphorylase) and amyloplast sugar transport (glucose-6-P translocator). Transcripts encoding AGPase SS and LS subunits with plastid localization were differentially induced during stem starch accumulation indicating that ADP-glucose for starch biosynthesis is primarily generated in stem plastids. Cytosolic heteroglucan metabolism may play a role in stem sucrose/starch accumulation because genes encoding cytosolic forms of the disproportionating enzyme and alpha-glucan phosphorylase were induced in parallel with stem sucrose/starch accumulation. Information on the stem starch pathway obtained in this study will be useful for engineering sorghum stems with elevated starch thereby improving forage quality and the efficiency of biomass conversion to biofuels and bio-products.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2018

An anaerobic-aerobic sequential batch process with simultaneous methanogenesis and short-cut denitrification for the treatment of marine biofoulings

Highlights: • Combined denitritation–methanogenesis was examined to treat intermittent wastes. • Achieved high NO{sub 2}{sup −} accumulation of 96.4% on average in nitritation. • Achieved high substrate COD removal of 96% in denitritation–methanogenesis. • Intensive effluent exchange enhanced nitrogen removal and decreased CH{sub 4} content. • Daily effluent exchange of 80% could maintain both effluent and biogas qualities. - Abstract: Although combination of denitritation and methanogenesis for wastewater treatment has been widely investigated, an application of this technology to solid waste treatment has been rarely studied. This study investigated an anaerobic-aerobic batch system with simultaneous denitritation-methanogenesis as an effective treatment for marine biofoulings, which is a major source of intermittently discharged organic solid wastes. Preliminary NO{sub 2}{sup −}-exposed sludge was inoculated to achieve stable methanogenesis process without NO{sub 2}{sup −} inhibition. Both high NH{sub 4}{sup +}-N removal of 99.5% and high NO{sub 2}{sup −}-N accumulation of 96.4% were achieved on average during the nitritation step. Sufficient CH{sub 4} recovery of 101 L-CH{sub 4} kg-COD{sup −1} was achieved, indicating that the use of NO{sub 2}{sup −}-exposed sludge is effective to avoid NO{sub 2}{sup −} inhibition on methanogenesis. Methanogenesis was the main COD utilization pathway when the substrate solubilization occurred actively, while denitritation was the main when solubilization was limited because of substrate shortage. The results showed a high COD removal efficiency of 96.0% and a relatively low nitrogen removal efficiency of 64.4%. Fitting equations were developed to optimize the effluent exchange ratio. The estimated results showed that the increase of effluent exchange ratio during the active solubilization period increased the nitrogen removal efficiency but decreased CH{sub 4} content in biogas. An appropriate effluent exchange ratio with high anaerobic effluent quality below approximately 120 mg-N L{sup −1} as well as sufficient CH{sub 4} gas quality which can be used as fuel for gas engine generator was achieved by daily effluent exchange of 80% during the first week and 5% during the subsequent 8 days.

09 BIOMASS FUELS↗

DOE OSTI2013

Lithium implantation at low temperature in silicon for sharp buried amorphous layer formation and defect engineering

The crystalline-to-amorphous transformation induced by lithium ion implantation at low temperature has been investigated. The resulting damage structure and its thermal evolution have been studied by a combination of Rutherford backscattering spectroscopy channelling (RBS/C) and cross sectional transmission electron microscopy (XTEM). Lithium low-fluence implantation at liquid nitrogen temperature is shown to produce a three layers structure: an amorphous layer surrounded by two highly damaged layers. A thermal treatment at 400 Degree-Sign C leads to the formation of a sharp amorphous/crystalline interfacial transition and defect annihilation of the front heavily damaged layer. After 600 Degree-Sign C annealing, complete recrystallization takes place and no extended defects are left. Anomalous recrystallization rate is observed with different motion velocities of the a/c interfaces and is ascribed to lithium acting as a surfactant. Moreover, the sharp buried amorphous layer is shown to be an efficient sink for interstitials impeding interstitial supersaturation and {l_brace}311{r_brace} defect formation in case of subsequent neon implantation. This study shows that lithium implantation at liquid nitrogen temperature can be suitable to form a sharp buried amorphous layer with a well-defined crystalline front layer, thus having potential applications for defects engineering in the improvement of post-implantation layers quality and for shallow junction formation.

36 MATERIALS SCIENCE↗

DOE OSTI2019

Machine-Learning Analysis of Moisture Carryover in Boiling Water Reactors

Moisture carryover (MCO) is modeled in the General Electric Type-4 boiling water reactor (BWR) using machine-learning methods and data from operating plants. Understanding MCO and the conditions that give rise to an elevated value is important since excessive MCO can damage critical turbine components, can result in elevated dose levels to on-site personnel, and can interfere with late-cycle power management. The analysis of MCO takes into account simplifying reactor symmetries and important geometric dependencies. The plant data are taken from several reactors and were collected over multiple years and multiple fuel cycles. A brief description of the origin of MCO in U.S. BWR plants is given. A machine-learning model is constructed from the data using applicable algorithms and data-reduction techniques. Matching model complexity with available data is one of the more challenging machine-learning tasks. Too many features and too little data will lead to overfitting. The data for each fuel cycle included over 6876 original features, 9 for each fuel bundle. Two approaches are used to reduce the data set into a manageable number of features. The first was an engineering analysis that resulted in the selection of steam quality Q and steam liquid phase velocity V L as the main features driving MCO. Using a Q and a V L for each fuel bundle gives 1528 Q and a V L feature describing the reactor behavior. An analysis of different functional forms of these two variables led to the actual inputs to the neural network model. The second approach involved the use of statistical techniques such as Pearson’s correlation and k-means analysis. The identified groupings of bundles behaved similarly. Treating each grouping as a single feature further reduced the input variable set to a manageable number. Here, a model selection criterion is proposed, and results are presented along with a discussion of related issues.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2016

Adaptive QoS for Data Transfers using Software-Defined Networking

Software-defined networking (SDN) has demonstrated tremendous potential for altering the networking landscape in both academia andindustry. While traffic engineering as network intelligence in classic technologies have received considerable attention from the researchcommunity, traffic engineering in the SDN space, particularly in regards to quality of service (QoS), remains relatively unexplored.While recent efforts have begun to show how SDN might be leverage to meet the complex traffic-shaping needs of modern networks, there is still much that can be done to illustrate its potential, and in particular how it could prevent degradation of service for all QoStraffic. We propose methods to allow other flows to use bandwidth unused by high-priority transfers, while ensuring that bandwidthassigned to those high-priority transfers is available when needed. We present fine-tuned control over bandwidth allocation that achieves an efficient combination of both the differentiated service (DiffServ)-style classification and the integrated service (IntServ)-style perflowconsiderations. We also show how this method may be used over a wide area network (WAN) to optimally adjust bandwidth allocations when high-priority data transfers are not using their allocated bandwidth.

Boley, Josh↗

DOE OSTI2015

Low-cost, highly transparent flexible low-e coating film to enable electrochromic windows with increased energy savings

Five Quads of energy are lost through windows annually in the U.S. Low-e coatings are increasingly employed to reduce the wasted energy. Most commonly, the low-e coating is an oxide material applied directly to the glass at high temperature. With over 100,000,000 existing homes, a retrofit product is crucial to achieve widespread energy savings. Low-e films, i.e. coatings on polymeric substrates, are now also available to meet this need. However, the traditional oxide materials and process is incompatible with low temperature plastics. Alternate high performing low-e films typically incorporate materials that limit visible transmission to 35% or less. Further, the cost is high. The objective of this award was to develop a retrofit, integrated low-e/electrochromic window film to dramatically reduce energy lost through windows. While field testing of state-of-the-art electrochromic (EC) windows show the energy savings are maximized if a low-e coating is used in conjunction with the EC, available low-e films have a low visible transmission (~70% or less) that limits the achievable clear state and therefore, appearance and energy savings potential. Comprehensive energy savings models were completed at Lawrence Berkeley National Lab (LBNL). A parametric approach was used to project energy usage for windows with a large range of low-e properties across all U.S. climate zones, without limiting the study to materials that had already been produced commercially or made in a lab. The model enables projection of energy savings for low-e films as well as integrated low-e/EC products. This project developed a novel low-e film, optimized for compatibility with EC windows, using low temperature, high deposition rate processes for the growth of low-e coatings on plastic films by microwave plasma enhanced chemical vapor deposition. Silica films with good density and optical properties were demonstrated at deposition rates as high as 130Å/sec. A simple bi-layer low-e stack of silica and a transparent conductive oxide demonstrated 90% visible transmission with high thermal infrared reflectivity characteristic of conventional low-e coatings. A slightly more complex stack provided high solar infrared reflection without sacrificing visible transmission or thermal infrared reflection. Successful completion of the effort produced a prototype integrated low-e, dynamic window film with characterized energy saving potential. Cost modeling for the passive bi-layer, low-e film projects a manufacturing cost of ~$0.50/ft2 for a plant with 10M ft2/yr capacity. The novel thin film processes developed here enable high deposition rate (low cost), optical quality oxide coatings at low temperatures. When combined with engineered materials, ITN’s coating will result in low-cost, low-e films that reflect a high degree of infrared radiation without substantially reducing the visible transmission. The resultant window film will improve the U-value and achieve SHGC improvements over bare glass. The new low-e coating will be particularly attractive when combined with an electrochromic film. Low-e coating design guided by energy savings modeling allows customization of the product for different climate zones.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2020

Arroyo Seco Improvement Program ( 2019 Annual Report)

The Arroyo Seco Improvement Program is being carried out at Sandia National Laboratories, California in order to address erosion and other streambed instability issues in the Arroyo Seco as it crosses the Sandia National Laboratories, California. The work involves both repair of existing eroded areas, and habitat enhancement. This work is being carried out under the requirements of Army Corps of Engineers permit 2006-400195S and California Regional Water Quality Control Board, San Francisco Bay Region Water Quality Certification Site No. 02-01-00987.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2020

Low Size, Weight, and Power Space-Based Imaging System

The proposed low-SWAP solution is a FPA focus mechanism which is composed of an actuator motor, attached to a flexure that holds the camera sensor while imaging. The mechanism, while moderately complex, allows for large changes in the focal plane while also maintaining the ability to make small adjustments to produce the best possible data. This solution does the best job at accounting for thermal gradients within the optical components that tend to degrade the image quality.

42 ENGINEERING↗

DOE OSTI2021

Arroyo Seco Improvement Program Annual Report for 2020

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2023

Laser Welded Burst Disk Weld Tooling

A production run of 5550 hermetically sealed cylinder assemblies with precision pressure relief burst discs will be assembled and laser welded at a manufacturing lab at Sandia National Labs. Production of these cylinder assemblies requires many steps, including piece part machining, geometric inspection, cleaning, subassembly, complete assembly via laser welding, and finally leak checking. While this production run is large enough to invest in process optimization and specialized tooling, it is not quite large enough to dedicate new lab space and specify equipment specifically for this job. This study will investigate process parameters and their effects on quality and process flow time, as well as a fixturing design study with the goal of reducing process time while maintaining quality requirements.

42 ENGINEERING↗

DOE OSTI2025

Evaluation of a 5kW Solid Oxide Electrolysis Cell Stack

Solid oxide electrolysis cells (SOECs) are a developing technology for hydrogen production. They are promising due to their utilization of thermal energy to reduce their electricity consumption. The Department of Energy (DOE) has set goals to reduce the price per kilogram of hydrogen, and Idaho National Laboratory (INL) is conducting research to develop and demonstrate advanced methods and technologies to achieve making hydrogen a more affordable, efficient, and sustainable energy source. In this project, INL is collaborating with a vendor to evaluate and validate the design of a 5kW SOEC stack. The test aims to demonstrate a safe startup, operation, and shutdown on INL’s 5kW test stand, providing third-party validation in a different environment. A successful 50-hour test with stable hydrogen production will pave the way for a subsequent 1000-hour test. This project emphasized learning about electrolysis and the various support systems, referred to as balance of plant (BOP) equipment. These systems required modification while swapping to the vendor 5kW SOEC stack, most prominently the furnace door design and the controls system. It also included gaining skills in creating computer-aided design (CAD) drawings for the new door while using available materials and ensuring it met high-temperature requirements. Upon completion of modifications to the test stand, the SOEC will be test-fitted with respective wiring and piping. Instrumentation and piping will be checked for leaks and quality. This must be completed before the vendor’s engineers arrive to observe the test plan, startup, and a collection of 50 hours of data. The vendor’s engineers will ensure their stack performed sufficiently in the 50-hour test to enable the progression to a 1000-hour test.

08 - HYDROGEN↗

NASA NTRS1968

Investigation of electron beam welds in a sensor tube

Weld quality of electron beam welded sensor tube for LOX engine cutoff sensor

Ceasar, T.↗

NASA NTRS1972

Portable life support for instrumentation of an offshore platform

A compressor was used to supply air through a nylon hose to the offshore platform field engineer working at the bottom of the piling. Air quality in the pile was sampled periodically for carbon dioxide, carbon monoxide, hydrogen sulfide, and combustible gases by an universal tester and an explosion meter.

Mull, M. M.↗

NASA NTRS1973

Cartographic quality of ERTS-1 images

Analyses of simulated and operational ERTS images have provided initial estimates of resolution, ground resolution, detectability thresholds and other measures of image quality of interest to earth scientists and cartographers. Based on these values, including an approximate ground resolution of 250 meters for both RBV and MSS systems, the ERTS-1 images appear suited to the production and/or revision of planimetric and photo maps of 1:500,000 scale and smaller for which map accuracy standards are compatible with the imaged detail. Thematic mapping, although less constrained by map accuracy standards, will be influenced by measurement thresholds and errors which have yet to be accurately determined for ERTS images. This study also indicates the desirability of establishing a quantitative relationship between image quality values and map products which will permit both engineers and cartographers/earth scientists to contribute to the design requirements of future satellite imaging systems.

Welch, R. I.↗

NASA NTRS1976

Model investigation of inlet plenum flow straightening techniques for altitude test facility

An investigation was conducted to evaluate and improve the quality of the airflow to be supplied to the engine in altitude test chambers 3 and 4 of the Propulsion Systems Laboratory at the Lewis Research Center. One-twentieth-scale models of the inlet plenum chamber of the two test chambers were used in the investigation to minimize time and cost. It was possible to reduce the velocity spread in the inlet plenum from approximately 100 m/sec (330 ft/sec) to approximately 10 m/sec (30 ft/sec) through the combined use of flow diverters, multiple spaced screens, flow straighteners, and turning vanes.

Riddlebaugh, S. M.↗

NASA NTRS1976

Development of EPA aircraft piston engine emission standards

Piston engine light aircraft are significant sources of carbon monoxide in the vicinity of high activity general aviation airports. Substantial reductions in carbon monoxide were achieved by fuel mixture leaning using improved fuel management systems. The air quality impact of the hydrocarbon and oxides of nitrogen emissions from piston engine light aircraft were insufficient to justify the design constraints being confronted in present control system developments.

Houtman, W.↗

NASA NTRS1980

Propulsion system research and development for electric and hybrid vehicles

An approach to propulsion subsystem technology is presented. Various tests of component reliability are described to aid in the production of better quality vehicles. component characterization work is described to provide engineering data to manufacturers on component performance and on important component propulsion system interactions.

Schwartz, H. J.↗

NASA NTRS1982

Metal honeycomb to porous wireform substrate diffusion bond evaluation

Two nondestructive techniques were used to evaluate diffusion bond quality between a metal foil honeycomb and porous wireform substrate. The two techniques, cryographics and acousto-ultrasonics, are complementary in revealing variations of bond integrity and quality in shroud segments from an experimental aircraft turbine engine.

Vary, A.↗