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At least 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Addition of terpenoids to pear ester plus acetic acid increases catches of codling moth (Lepidoptera: Tortricidae)

Abstract Field studies were conducted to evaluate new kairomone blends in combination with pear ester ( E,Z )‐2,4‐ethyl decadienoate (PE) and acetic acid (AA) for their attraction of male and female codling moth, Cydia pomonella (L.), in apple, Malus domestica Borkhausen. The addition of decanal to either AA or PE alone significantly increased total and female moth catches. However, the addition of decanal did not improve the attraction of PE + AA. The addition of either the pyranoid (PyrLOX) or furanoid (FurLOX) linalool oxide but not linalool (LOL) increased moth catches with PE but did not increase catches with PE + AA. Similarly, the addition of PyrLOX plus decanal did not improve PE + AA. The addition of ( E )‐4,8‐dimethyl‐1,3,7‐nonatriene (DMNT) to either AA, PE + AA or PE + AA+decanal did not significantly increase moth catches. However, the addition of PyrLOX to traps with PE + AA and DMNT (4‐component lure) significantly increased moth catches compared with PE + AA alone or any of the ternary blends of these volatiles. Females accounted for 60%–80% of the total catch with this 4‐component lure. The 4‐component blend with PyrLOX was a more attractive lure than similar blends that substituted LOL, or a binary blend of LOL and FurLOX for PyrLOX. The 4‐component blend caught nearly fourfold more total and female moths than the purported attractant N‐butyl sulphide when it was used in combination with PE + AA. These results indicate that significant improvements in monitoring, mating disruption and mass trapping of codling moth are possible. Further studies are needed to assess the new attractive blend's effectiveness in combination with sex pheromone lures and to evaluate whether other host plant volatiles can be added or substitute for DMNT or LOX when used in combination with PE + AA.

Knight, Alan L.↗
DOE OSTI2021

Microbial Community Shifts Reflect Losses of Native Soil Carbon with Pyrogenic and Fresh Organic Matter Additions and Are Greatest in Low-Carbon Soils

ABSTRACT Soil organic carbon (SOC) plays an important role in regulating global climate change, carbon and nutrient cycling in soils, and soil moisture. Organic matter (OM) additions to soils can affect the rate at which SOC is mineralized by microbes, with potentially important effects on SOC stocks. Understanding how pyrogenic organic matter (PyOM) affects the cycling of native SOC (nSOC) and the soil microbes responsible for these effects is important for fire-affected ecosystems as well as for biochar-amended systems. We used an incubation trial with five different soils from National Ecological Observatory Network sites across the United States and 13 C-labeled 350°C corn stover PyOM and fresh corn stover OM to trace nSOC-derived CO 2 emissions with and without PyOM and OM amendments. We used high-throughput sequencing of rRNA genes to characterize bacterial, archaeal, and fungal communities and their responses to PyOM and OM in soils that were previously stored at −80°C. We found that the effects of amendments on nSOC-derived CO 2 reflected the unamended soil C status, where relative increases in C mineralization were greatest in low-C soils. OM additions produced much greater effects on nSOC-CO 2 emissions than PyOM additions. Furthermore, the magnitude of the microbial community composition change mirrored the magnitude of increases in nSOC-CO 2 , indicating that a specific subset of microbes was likely responsible for the observed changes in nSOC mineralization. However, PyOM responders differed across soils and did not necessarily reflect a common “charosphere.” Overall, this study suggests that soils that already have low SOC may be particularly vulnerable to short-term increases in SOC loss with OM or PyOM additions. IMPORTANCE Soil organic matter (SOM) has an important role in global climate change, carbon and nutrient cycling in soils, and soil moisture dynamics. Understanding the processes that affect SOM stocks is important for managing these functions. Recently, understanding how fire-affected organic matter (or “pyrogenic” organic matter [PyOM]) affects existing SOM stocks has become increasingly important, due to both changing fire regimes and interest in “biochar,” pyrogenic organic matter that is produced intentionally for carbon management or as an agricultural soil amendment. We found that soils with less SOM were more prone to increased losses with PyOM (and fresh organic matter) additions and that soil microbial communities changed more in soils that also had greater SOM losses with PyOM additions. This suggests that soils that already have low SOM content may be particularly vulnerable to short-term increases in SOM loss and that a subset of the soil microbial community is likely responsible for these effects.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Additive-Mixing Fuel Injection (AMFI): A device for robust control and improved performance of high-efficiency LTGC engines

Low-temperature gasoline combustion (LTGC) engines can provide high efficiencies with very low NOx and particulate emissions. Despite these major advantages, methods for controlling LTGC combustion timing, achieving robust autoignition, and good low-load performance have challenged the development of practical LTGC engines. A key reason is that the ideal reactivity of the fuel varies with operating conditions, with low-reactivity fuels working well at high loads and higher-reactivity fuels working better at low loads. This article introduces a new technique called Additive Mixing Fuel Injection (AMFI) that adjusts the reactivity of the gasoline to obtain good performance over the operating map. Moreover, AMFI can provide robust combustion-timing control because it precisely meters very small amounts (0.01–0.6 mm 3 ) of an ignition-enhancing additive into the fuel each engine cycle. The additive used was 2-ethylhexyl nitrate (EHN), a common, inexpensive diesel-fuel ignition improver, but other additives could be used. Because additive amounts are so small, a 2-gal reservoir would be sufficient for medium-duty applications with refilling only at service intervals of about 8000 mi. The AMFI system has been installed on a single-cylinder LTGC research engine and demonstrated to provide robust combustion-timing control over wide ranges of combustion phasing, fueling rate, intake boost, engine speed, and intake temperature. AMFI also increases the fuel’s reactivity sufficiently to greatly reduce or eliminate the need for charge heating, simplifying engine design and significantly increasing thermal efficiency and the maximum load at low-boost conditions. The nitrogen in the EHN produced a modest increase in NOx, but it was mitigated by lower intake temperatures, and NOx emissions remained very low. Finally, the additive increases the sensitivity of autoignition reactions to variations in the local fuel/air mixture within the charge. This allows the use of controlled fuel stratification for improved LTGC-engine performance, and its potential to improve low-load operation was demonstrated.

Dec, John E.↗
DOE OSTI2016

2015 Summer Design Challenge: Team A&E (2241) Additively Manufactured Discriminator.

Current discriminator designs are based on historical designs and traditional manufacturing methods. The goal of this project was to form non-traditional groups to create novel discriminator designs by taking advantage of additive manufacturing. These designs would expand current discriminator designs and provide insight on the applicability of additive manufacturing for future projects. Our design stretched the current abilities of additive manufacturing and noted desired improvements for the future. Through collaboration with NSC, we noted several additional technologies which work well with additive manufacturing such as topology optimization and CT scanning and determined how these technologies could be improved to better combine with additive manufacturing.

42 ENGINEERING↗
DOE OSTI2017

Additively Manufactured, Net Shape Powder Metallurgy Cans for Valves Used in Energy Production

Additive manufacturing (AM) has the potential to enable a paradigm shift in fabricating complex net shape components with yields over 90%, significantly increasing productivity, decreasing energy consumption during manufacturing and improving downstream energy efficiency. ORNL has developed a technology for producing large-scale additively manufactured polymer matrix composite components at deposition rates on the order of 100 lbs. per hour. This project utilized tools, dies and molds made from this technology to enable the net shape forming of cans for the powder metallurgy (PM) manufacturing of valves used in energy production plants. This approach has the potential to develop affordable valves with superior performance to castings. It will also lead to increased strength values, decreased wall thickness size, and the potential for higher yields (less machining). This project is critical for evaluating new methodologies for the fabrication of additively manufactured tooling, molds and dies that could be used across multiple industries. In the first phase of this project, a new methodology of creating a Powder Metallurgy and Hot Isostatic Pressing (PM-HIP) container by hydroforming sheet metal over additively manufactured (AM) dies was evaluated. The goal in this stage of development was to evaluate some of the new polymer matrix composite materials designed for deposition on large scale additive manufacturing systems as candidates for hydroforming steel and aluminum sheet to make thin gauge net shape components. In order to meet this objective, most research was performed on subscale tools in order to evaluate the processing pressures, material options, and gauge thicknesses most relevant to this approach. In addition, full scale AM tools (30% over final component geometry) were produced to demonstrate scalability, but were not used in testing. The first phase of this project has proven this concept has merit, but future studies are required to address minor tool failures that occurred in phase one due to geometry, cost of the process over other techniques, and demonstration of a full-scale tool that could then be used in (HIP). Lastly, this project provides the PM community a new approach in using hydroforming for the manufacturing of cans, a process that was not highly utilized for this purpose previously.

42 ENGINEERING↗
DOE OSTI2022

Additive Manufacturing Design Guidelines for Wind Industry

The purpose of this report is to equip wind industry professionals with the fundamental information needed to best leverage additive manufacturing techniques in their design and manufacturing decisions. Herein an overview of each of the seven families of additive manufacturing is provided, along with typical materials used in each process, current ranges on process speeds, materials and system costs, and examples of systems on the market today. Using the lens of large-scale additive to suit the needs of the wind industry, the processes that are well-suited to large-scale production are down selected from the seven families and additional information with design guidelines specific to each process are detailed. A companion document titled “Relevant Additive Manufacturing Materials for Wind Industry” elaborates on the specifics of relevant material properties and test methods for additive manufacturing materials.

17 WIND ENERGY↗
DOE OSTI2022

Additives in Localized High Concentration Electrolytes for Safe Lithium-Ion Batteries

In this work, the effects of various additives in a localized high concentration electrolyte (LHCE) on the cycling performance of lithium (Li)-ion batteries were studied. The LHCEs utilize trimethyl phosphate as a flame-retarding solvent and 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether as a medium-high flash point diluent, for the purpose to reduce the electrolyte flammability and improve the battery safety, which are not possessed by the conventional electrolytes of LiPF 6 in organic carbonates due to their high flammability. The LHCEs have unique solvation structure which enables the use of flame-retardant solvents to greatly decrease the electrolyte flammability as well as enhance the battery cycling stability. However, the additives added in the LHCEs result in different battery performances. The organic carbonate additives largely reduce the initial capacities although the cell capacity can be partially recovered with cycling. The two phosphate salt additives behave better than the organic carbonate additives in terms of cell capacity and cycling stability. More cell performance evaluation will be conducted and the detailed characterization will be performed to investigate the root causes of different behaviors of additives in the LHCEs on battery performances.

25 ENERGY STORAGE↗
DOE OSTI2019

Additive Technology in Optimal Synthesis of Individual Vehicle Components and Mechanisms

Experience in optimal synthesis of individual vehicle components and mechanisms on the basis of additive technology is analyzed. A list of basic additive technologies is presented. The benefits of additive technology in combination with three-dimensional computer simulation are noted. The possibility of visualizing CAE calculations by means of additive technology is considered. In addition, the role of additive technology in the manufacture of individual vehicle components and mechanisms is discussed.

42 ENGINEERING↗
NASA NTRS1973

Effect of lubricant extreme pressure additives on rolling element fatigue life

The effects of surface active additives on rolling-element fatigue life were investigated with the five-ball fatigue tester at conditions where classical subsurface initiated rolling-element fatigue is the sole mode of failure. Test balls of AISI 52100, AISI M-50, and AISI 1018 were run with an acid-treated white oil containing either 2.5 percent sulfurized terpene, 1 percent didodecyl phosphite, or 5 percent chlorinated wax. In general, it was found that the influence of surface active additives was detrimental to rolling-element fatigue life. The chlorinated-wax additive significantly reduced fatigue life by a factor of 7. The base oil with the 2.5 percent sulfurized-terpene additive can reduce fatigue life by as much as 50 percent. No statistical change in fatigue life occurred with the base oil having the 1 percent didodecyl-phosphite additive. The additives used with the base oil did not change the ranking of the bearing steels where rolling-element fatigue life was of subsurface origin.

Parker, R. J.↗
NASA NTRS1980

Drag reduction - Jet breakup correlation with kerosene-based additives

The drag-reduction effectiveness of a number of high-polymer additives dissolved in aircraft fuel has been measured in a turbulent-flow rheometer. These solutions were further subjected to high elongational stress and breakup forces in a jet discharging in air. The jet was photographed using a high-resolution camera with special lighting. The object of the work was to study the possible spray-suppression ability of high-polymer additives to aircraft fuel and to correlate this with the drag-reducing properties of the additives. It was found, in fact, that the rheometer results indicate the most effective spray-suppressing additives. Using as a measure the minimum polymer concentration to give a maximum friction-reducing effect, the order of effectiveness of eight different polymer additives as spray-suppressing agents was predicted. These results may find application in the development of antimisting additives for aircraft fuel which may increase fire safety in case of crash or accident.

Hoyt, J. W.↗
NASA NTRS1983

Evaluation of fuel additives for reduction of material imcompatibilities in methanol-gasoline blends

Screening tests determined the efficacy of six commercially available additives as modifiers of methanol's corrosivity toward metals and its weakening of tensile properties of nonmetals in automotive fuel systems. From the screening phase, three additives which seemed to protect some of the metals were tested in higher concentrations and binary combinations in search of optimal application conditions. Results indicate that two of the additives have protective properties and combining them increases the protection of the metals corroded by methanol-gasoline blends. Half of the metals in the tests were not corroded. Testing at recommended concentrations and then at higher concentrations and in combinations shows that the additives would have no protective or harmful effects on the nonmetals. Two additives emerged as candidates for application to the protection of metals in automotive methanol-gasoline fuel systems. The additives tested were assigned letter codes to protect their proprietary nature.

Rodriguez, C. F.↗
NASA NTRS1985

Lubricant and additive effects on spur gear fatigue life

Spur gear endurance tests were conducted with six lubricants using a single lot of consumable-electrode vacuum melted (CVM) AISI 9310 spur gears. The sixth lubricant was divided into four batches each of which had a different additive content. Lubricants tested with a phosphorus-type load carrying additive showed a statistically significant improvement in life over lubricants without this type of additive. The presence of sulfur type antiwear additives in the lubricant did not appear to affect the surface fatigue life of the gears. No statistical difference in life was produced with those lubricants of different base stocks but with similar viscosity, pressure-viscosity coefficients and antiwear additives. Gears tested with a 0.1 wt % sulfur and 0.1 wt % phosphorus EP additives in the lubricant had reactive films that were 200 to 400 (0.8 to 1.6 microns) thick.

Townsend, D. P.↗
NASA NTRS1986

Lubricant and additive effects on spur gear fatigue life

Spur gear endurance tests were conducted with six lubricants using a single lot of consumable-electrode vacuum melted (CVM) AISI 9310 spur gears. The sixth lubricants was divided into four batches each of which had a different additive content. Lubricant tested with a phosphorus-type load carrying additive showed a statistically significant improvement in life over lubricants without this type of additive. The presence of sulfur type antiwear additives in the lubricant did not appear to affect the surface fatigue life of the gears. No statistical difference in life was produced with those lubricants of different base stocks but with similar viscosity, pressure-viscosity coefficients and antiwar additives. Gears tested with a 0.1 wt pct sulfur and 0.1 wt pct phosphorus EP additives in the lubricant had reactive films that were 200 to 400 (0.8 to 1.6 microns) thick.

Townsend, D. P.↗
NASA NTRS2018

Systems and Methods for Additive Manufacturing Processes that Strategically Buildup Objects

Systems and methods in accordance with embodiments of the invention implement additive manufacturing techniques that employ different sets of deposition characteristics and/or material formation characteristics during the additive manufacture of an object so as to strategically build up the object. In many embodiments, material used to build up an object is deposited at different deposition rates during the additive manufacture of the object, and the object is thereby strategically built up. In one embodiment, a method of additively manufacturing an object includes: depositing material onto a surface at a first deposition rate so as to define a first region of the object to be additively manufactured; and depositing material onto a surface at a second deposition rate so as to define a second region of the object to be additively manufactured; where the second deposition rate is different from the first deposition rate.

Hofmann, Douglas C.↗
NASA NTRS2015

A Decision-Support Model for Selecting Additive Manufacturing Versus Subtractive Manufacturing Based on Energy Consumption

This paper presents a simple computational model for determining whether additive manufacturing or subtractive manufacturing is more energy efficient for production of a given metallic part. The key discriminating variable is the fraction of the bounding envelope that contains material – i.e. the volume fraction of solid material. For both the additive process and the subtractive process, the total energy associated with the production of a part is defined in terms of the volume fraction of that part. The critical volume fraction is that for which the energy consumed by subtractive manufacturing equals the energy consumed by additive manufacturing. For volume fractions less than the critical value, additive manufacturing is more energy efficient. For volume fractions greater than the critical value, subtractive manufacturing is more efficient. The model considers the entire manufacturing lifecycle – from production and transport of feedstock material through processing to return of post-production scrap for recycling. Energy consumed by processing equipment while idle is also accounted for in the model. Although the individual energy components in the model are identified and accounted for in the expressions for additive and subtractive manufacturing, values for many of these components may not be currently available. Energy values for some materials’ production and subtractive and additive manufacturing processes can be found in the literature. However, since many of these data are reported for a very specific application, it may be difficult, if not impossible, to reliably apply these data to new process-material manufacturing scenarios since, very often, insufficient information is provided to enable extrapolation to broader use. Consequently, this paper also highlights the need to develop improved knowledge of the energy embodied in each phase of the manufacturing process. To be most valuable, users of the model should determine the energy consumed by their manufacturing process equipment on the basis of energy-per-unit-volume of production for each material of interest – considering both alloy composition and form. Energy consumed during machine idle per unit time should also be determined by the user then scaled to specific processing scenarios. Energy required to generate feedstock material (billet, plate, bar, wire, powder) must be obtained from suppliers.

J K Watson↗
NASA NTRS2024

Effects of Oxide Dispersion on Failure Modes in an Additively Manufactured Superalloy

Additive manufacturing opens new paths for introducing oxide particles into superalloys, to potentially provide oxide dispersion strengthening (ODS) at high temperatures. This provides opportunities to study how such dispersions can influence failure modes for a given superalloy, after nearly identical material processing paths. The objective of this study was to compare monotonic failure modes for additively manufactured superalloys with versus without an introduced oxide dispersion. The superalloy for each case was produced by laser powder bed fusion additive manufacturing. Specimens were subsequently given consistent thermal treatment paths and then tested in tensile and creep tests at varied temperatures. Failure modes were then compared. Additively manufactured NiCrAl without ODS had randomly oriented equiaxed grains while this alloy with 0.25 wt% Y 2 O 3 ODS additions had elongated [001] oriented grains in the build direction. Material made without ODS (“No-ODS”) was nearly completely single phase gamma, while ODS additions resulted in gamma, chromium carbide, and Y-Al-Cr oxide phases, with carbide and oxide phases contents estimated at no more than 13 and 1 vol%, respectively. Compared to No-ODS, material made with ODS had higher tensile strengths at room, 760 and 1093 °C. The elongation of ODS material was lower than No-ODS at room temperature, but higher at 760 °C. At 1093 °C ODS material had higher elongation than No-ODS when tested in the build direction, however elongation was lower for ODS material in the transverse direction at 1093 °C. Creep rupture strain, life, and area reduction at 760 and 1093 °C were all much higher for ODS material compared to No-ODS; 760 °C rupture life was nearly 100 times longer for ODS material. The presence of Y in the ODS material significantly improved oxidation resistance.

supperalloys↗
DOE OSTI2019

Additive-mixing fuel-injection system for internal combustion engines

A system and method for fast control of the timing of combustion in an internal combustion engine, comprising actuating a fast-acting fuel-additive supply valve to meter a variable amount of fuel additive into a fuel stream, thereby forming an additive-enhanced fuel with an additive concentration that can be dynamically adjusted as fast as each engine cycle; injecting the additive-enhanced fuel directly or indirectly into a combustion chamber or into an intake port; and combusting the additive-enhanced fuel.

42 ENGINEERING↗
DOE OSTI2021

Methods and apparatus for embedding heating circuits into articles made by additive manufacturing and articles made therefrom

Methods of embedding a heating circuit in an article fabricated by additive manufacturing. The methods describe techniques such as co-extruding a wire, capable of being heated, along with print material in additive manufacturing of the article, and placing a pre-shaped wire capable of being heated between adjacent layers of the article. A third method includes dispensing a wire, capable of being heated, during the additive manufacturing of the article, and compacting the wire into the printed material. An apparatus for embedding a heating circuit in an article fabricated by additive manufacturing. The apparatus contains a wire dispenser, a cutter to control the length of the wire dispensed, and a compactor capable of embedding the wire capable of being heated into the printed material. An article made by additive manufacturing is disclosed. The article contains at least one heating element embedded in the article during the additive manufacturing process.

Barocio, Eduardo↗